On November the 10th departments and institutes of the Leibniz University Hannover offered visitors a comprehensive look into their current research efforts.

Together the research institute L3S (Leibniz University Hannover), ISU (the Institute for Sustainable Urbanism – TU Brunswig)  and 1KLANG®, (mobility brand – PROJEKTIONISTEN® GmbH), showcased their joint research project Data4UrbanMobility.

Interested visitors were able try out all of the apps and dashboards that are being developed as a part of the research project.

(for fruther details: https://data4urbanmobility.l3s.uni-hannover.de/index.php/en/results/).

One of the highlights was the new iOS version of the “MiC” app that now supports Apple Watch.

We’re grateful for all of the insightful discussions we were able to have with the attendees at the event and are looking forward to sharing our beta of the Citizen Science App „MiC – Move in the City“ with so many new volunteers.

• The accelerating digital transformation in manufacturing enhances automation and production efficiency, requiring employees to develop new skills to meet evolving demands. This case study examines how Siemens embeds a human-centric bottom-up approach to empower employee re- and upskilling through innovative digital learning. Aligned with Siemens’ actions, we present a four-phase model on leveraging information systems to address skill gaps, enhance adaptability and tackle re- and upskilling challenges. Moreover, we provide five recommendations for organizations fostering lifelong learning in dynamic manufacturing environments.
• SIREN: Scalable isotropic recursive column multimodal neural architecture. Truchan, Hubert; Farag, Alan; Ahmadi, Zahra (2026). 125 103500.
• Automated Code Annotation with LLMs for Establishing TEE Boundaries. Gadey, Varun; Götz, Melanie; Sendner, Christoph; Sovio, Sampo; Dmitrienko, Alexandra (2026).
• SIREN: Scalable isotropic recursive column multimodal neural architecture. Truchan, Hubert; Farag, Alan; Ahmadi, Zahra (2026). 125 103500.
• A Mathematical Model for XOR-Based Application Specific DRAM Address Mapping Schemes. Rotaru, Andrei; Bachtler, Oliver; Steiner, Lukas; Jung, Matthias; Krumke, Sven O.; Wehn, Norbert (2025). (Vol. 11)
• Topology in thermoelectric materials. He, Bin; Toriyama, Michael; Snyder, G. Jeffrey; Felser, Claudia; Pan, Yu (2025).

  The combination of thermoelectricity and electronic band topology has emerged as a frontier area of research, promising to provide new mechanisms for enhancing thermoelectric performance in various material systems. Topological materials, including topological insulators and Weyl/Dirac/nodal line topological semimetals, exhibit unique electronic properties such as band inversion, protected surface states, linear band dispersion, and nontrivial Berry curvature, all of which significantly influence thermoelectric transport phenomena. These features contribute to enhanced thermoelectric performance through mechanisms such as band inversion-driven warping and the anomalous Nernst effect. This article summarizes the current landscape of topological materials in thermoelectrics, emphasizing its potential to revolutionize energy technologies and outlining future research directions aimed at discovering new candidates.
• Performance and Power Analysis of LPDDR6. Christ, Derek; Steiner, Lukas; Zimmermann, Thomas; Mörz, Marco; Wilbert, Nils; Jung, Matthias; Wehn, Norbert (2025). (Vol. 1)
• Performance and Power Analysis of LPDDR6. Christ, Derek; Steiner, Lukas; Zimmermann, Thomas; Mörz, Marco; Wilbert, Nils; Jung, Matthias; Wehn, Norbert (2025). (Vol. 1)
• Protocol: Scoping review of the association between complementary feeding, growth, and immune health in infants and toddlers-An EAACI guideline paper. Venter, Carina; Alonso-Coello, Pablo; Beltran, Jessica; Bracchiglione, Javier; Fernandez-Saenz, Karina; Riera, Pau; Solà, Ivan; Arasi, Stefania; Berni Canani, Roberto; Fleischer, David; Eguíluz-Gracia, Ibon; Meyer, Rosan; Roberts, Graham; Roth-Walter, Franziska; Santos, Alexandra F; Skypala, Isabel; Smith, Peter K; Sokolowska, Milena; Torres, Maria J; Vassilopoulou, Emilia; Walter, Jens; O’Mahony, Liam (2025). 36(8) e70145-e70145.

  The European Academy of Allergy and Clinical Immunology (EAACI) is currently developing guidelines on immunomodulation and nutrition. To inform these recommendations, a scoping review will be conducted to synthesize and map the available empirical evidence on how complementary feeding affects immune health in infants and toddlers to explore the association between complementary feeding during the first year of life and immune health outcomes in children up to 3 years of age. The scoping review will be conducted using the Preferred Reporting Items for Systematic Reviews and Meta-analysis Scoping Review Extension for scoping reviews (PRISMA-ScR) guidelines. We have developed inclusion criteria using the PCC (Population, Concept and Context) format: the population will include healthy infants; the concept refers to specific factors related to introduction of complementary feeding; and the context will focus on studies conducted in settings representative of everyday nutrition and feeding practices for infants and toddlers. Evidence sources include systematic reviews. We will search in MEDLINE and Epistemonikos. Data will be extracted using a standardized form developed in REDCap, and the findings will be synthesized narratively. Only published literature will be included in this systematic review. Therefore, no ethical approval is required. The final review paper will be published in a peer-reviewed journal. OSF registration DOI: 10.17605/OSF.IO/T5F8.
• Demonstration of domain wall current in MgO-doped lithium niobate single crystals up to 400°C. Wulfmeier, Hendrik; Yakhnevych, Uliana; Boekhoff, Cornelius; Diima, Allan; Kunzner, Marlo; Verhoff, Leonard M.; Paul, Jonas; Ratzenberger, Julius; Beyreuther, Elke; Gössel, Joshua; Kiseleva, Iuliia; Rüsing, Michael; Sanna, Simone; Eng, Lukas M.; Fritze, Holger (2025). 429 116949-.

  Conductive ferroelectric domain walls (DWs) represent a promising topical system for the development of nanoelectronic components and device sensors to be operational at elevated temperatures. DWs show very different properties as compared to their hosting bulk crystal, in particular with respect to the high local electrical conductivity. The objective of this work is to demonstrate DW conductivity up to temperatures as high as 400°C which extends previous studies significantly. Experimental investigation of the DW conductivity of charged, inclined DWs is performed using 5mol% MgO-doped lithium niobate single crystals. Current–voltage (IV ) curves are determined by DC electrometer measurements and impedance spectroscopy and found to be identical. Moreover, impedance spectroscopy enables to recognize artifacts such as damaged electrodes. Temperature dependent measurements over repeated heating cycles reveal two distinct thermal activation energies for a given DW, with the higher of the activation energies only measured at higher temperatures. Depending on the specific sample, the higher activation energy is found above 160°C to 230°C. This suggests, in turn, that more than one type of defect/polaron is involved, and that the dominant transport mechanism changes with increasing temperature. First principles atomistic modeling suggests that the conductivity of inclined domain walls cannot be solely explained by the formation of a 2D carrier gas and must be supported by hopping processes. This holds true even at temperatures as high as 400°C. Our investigations underline the potential to extend DW current based nanoelectronic and sensor applications even into the so-far unexplored temperature range up to 400°C.
• Dynamical response theory of interacting Majorana fermions and its application to generic Kitaev quantum spin liquids in a field. Rao, Peng; Moessner, Roderich; Knolle, Johannes (2025). 112(2) 024440.
• Read my LIPSS: organic lasers on micromachined resonators. Dong, Tiange; Antrack, Tobias; Pietsch, Frithjof; Lindenthal, Jakob; Löffler, Markus; Rellinghaus, Bernd; Benduhn, Johannes; Sudzius, Markas; Leo, Karl (2025). 16(1) 7057.

  Thin-film lasers based on organic semiconductors offer significant potential for miniaturized sensing and optical memory. We present a new method for creating first-order distributed feedback (DFB) Bragg gratings using laser-induced periodic surface structures (LIPSS) as the optical resonator. These subwavelength structures, fabricated via femtosecond laser micromachining, exhibit stable periodicities and provide sufficient feedback for lasing in an Alq3:DCM film. The laser emission wavelength can be widely tuned by varying the LIPSS periodicity defined by the pulse spacing of the structuring laser. While lasing is limited by LIPSS imperfections, we demonstrate that individual LIPSS gratings optically couple into a coherent macroscopic supermode. This coupling dramatically increases lasing efficiency and reduces thresholds by two orders of magnitude compared to a single LIPSS element. This straightforward fabrication enables solid-state organic DFB lasers as integrated, on-chip coherent light sources, eliminating complex external coupling into photonic circuits.
• Exploiting LPDDR6 Metadata to Cache Byte-Addressable Non-Volatile Main Memories. Wilbert, Nils; Christ, Derek; Jung, Matthias (2025). (Vol. 1)
• Observation of resistive switching and diode effect in the conductivity of TiTe\($_\mathbf2$\) point contacts. Kvitnitskaya, O. E.; Harnagea, L.; Feia, O. D.; Efremov, D. V.; Büchner, B.; Naidyuk, Yu. G. (2025). 51(7) 856–860.

  We measured the I(V) and dV/dI(V) characteristics of TiTe2-based point contacts (PCs) from room to helium temperatures. Features indicating the emergence of charge density wave (CDW) were detected. They represent symmetrical relatively V = 0 maxima in dV/dI(V) around ±150 mV at liquid helium temperatures, which disappear above 150 K, similar to the case of sister CDW compound TiSe2. Applying higher voltages above 200 mV, we observed resistive switching in TiTe2 PCs from a metallic-like low-resistance state to a non-metallic type high-resistance state with a change of resistance by an order of magnitude. A unique diode-like effect was registered in “soft” TiTe2 PCs with hysteretic I(V) at the negative voltage on TiTe2. Discovering the resistive switching and diode effect adds TiTe2 to the transition-metal dichalcogenides, which could be useful in developing non-volatile ReRAM and other upcoming nanotechnologies.
• Collective nuclear excitation and pulse propagation in single-mode X-ray waveguides. Lohse, Leon M.; Andrejić, Petar; Velten, Sven; Vassholz, Malte; Neuhaus, Charlotte; Negi, Ankita; Panchwanee, Anjali; Sergeev, Ilya; Pálffy, Adriana; Salditt, Tim; Röhlsberger, Ralf (2025). 135(5) 053601.
• Hidden order and ℤ\($_\mathbf2$\) confinement transition in a fully packed monopole liquid. Szabó, Attila; Grigera, Santiago A.; Holdsworth, P. C. W.; Jaubert, Ludovic D. C.; Moessner, Roderich; Slobinsky, Demian G.; Sturla, Mauricio; Borzi, Rodolfo A. (2025). 112(1) 014452.
• Topological Weyl altermagnetism in CrSb. Li, Cong; Hu, Mengli; Li, Zhilin; Wang, Yang; Chen, Wanyu; Thiagarajan, Balasubramanian; Leandersson, Mats; Polley, Craig; Kim, Timur; Liu, Hui; Fulga, Cosma; Vergniory, Maia G.; Janson, Oleg; Tjernberg, Oscar; van den Brink, Jeroen (2025). 8(1) 311.

  Altermagnets constitute a novel, third fundamental class of collinear magnetic ordered materials, alongside with ferro- and antiferromagnets. They share with conventional antiferromagnets the feature of a vanishing net magnetization. At the same time they show a spin-splitting of electronic bands, just as in ferromagnets, caused by the atomic exchange interaction. On the other hand, topology has recently revolutionized our understanding of condensed matter physics, introducing new phases of matter classified by intrinsic topological order. Here we connect the worlds of altermagnetism and topology, showing that the electronic structure of the altermagnet CrSb is topological. Using high-resolution angle-resolved photoemission spectroscopy, we observe the large momentum-dependent spin-splitting in CrSb that induces altermagnetic Weyl nodes. We observe the related topological Fermi-arcs, which in electronic structure calculations are spin polarized. This indicates that in altermagnets the large energy scale intrinsic to their spin-splitting creates its own realm of robust electronic topology.
• Exploiting LPDDR6 Metadata to Cache Byte-Addressable Non-Volatile Main Memories. Wilbert, Nils; Christ, Derek; Jung, Matthias (2025). (Vol. 1)
• AI Is a Mass-Delusion Event. Warzel, Charlie (2025).

  Three years in, one of AI’s enduring impacts is to make people feel like they’re losing it.
• A Mathematical Model for XOR-Based Application Specific DRAM Address Mapping Schemes. Rotaru, Andrei; Bachtler, Oliver; Steiner, Lukas; Jung, Matthias; Krumke, Sven O.; Wehn, Norbert (2025). (Vol. 11)
• Learning Fluid-Structure Interaction Dynamics with Physics-Informed Neural Networks and Immersed Boundary Methods. Farea, Afrah; Khan, Saiful; Daryani, Reza; Ersan, Emre Cenk; Celebi, Mustafa Serdar (2025).

  We introduce neural network architectures that combine physics-informed neural networks (PINNs) with the immersed boundary method (IBM) to solve fluid-structure interaction (FSI) problems. Our approach features two distinct architectures: a Single-FSI network with a unified parameter space, and an innovative Eulerian-Lagrangian network that maintains separate parameter spaces for fluid and structure domains. We study each architecture using standard Tanh and adaptive B-spline activation functions. Empirical studies on a 2D cavity flow problem involving a moving solid structure show that the Eulerian-Lagrangian architecture performs significantly better. The adaptive B-spline activation further enhances accuracy by providing locality-aware representation near boundaries. While our methodology shows promising results in predicting the velocity field, pressure recovery remains challenging due to the absence of explicit force-coupling constraints in the current formulation. Our findings underscore the importance of domain-specific architectural design and adaptive activation functions for modeling FSI problems within the PINN framework.
• Platelets drive macrophage inflammatory activation in vitro. Rizakou, Anna; Rosa, Annabelle; Weiss, Lukas Johannes; Sakalli, Ecem T; Rizzo, Giuseppe; Burkard, Philipp; Arampatzi, Panagiota; Beck, Sarah; Gundel, Shanice; Klapproth, Kimberly; Bandi, Sourish Reddy; Piollet, Marie; Göb, Vanessa; Schulze, Harald; Stegner, David; Zernecke, Alma; Nieswandt, Bernhard; Cochain, Clement (2025).

  Macrophages have a dual role in tissue healing after injury as they perform tissue repair functions but can also precipitate tissue damage or promote fibrosis. Platelets, beyond their role in thrombosis and hemostasis, are crucial mediators of inflammation and interact with macrophages. Platelet-macrophage interactions have been proposed to modulate macrophage phenotype, including their profibrotic functions, but the full extent of the platelet impact on the macrophage transcriptome is unknown. Here, we aimed to investigate how platelets affect macrophage activation in vitro. Using experimental myocardial infarction (MI) in mice as a model of sterile tissue injury, we readily visualized the direct interaction of platelets with macrophages in the ischemic heart using fluorescence microscopy. Bulk RNA-sequencing of mouse bone marrow-derived macrophages co-cultured in vitro with thrombin-activated platelets showed a widespread pro-inflammatory activation, with up-regulation of genes associated with inflammation (Il1b, Trem1, Tlr2, Cd14), angiogenesis (Vegfa) and response to hypoxia (Hif1a). Resting platelets also led to activation of inflammatory gene expression by macrophages, albeit to a much lesser extent. Activated or resting platelets, or the platelet-derived chemokine CXCL4, had a limited impact on macrophage expression of pro-fibrotic genes (Spp1, Fn1). Using a transwell assay, we further demonstrate that the pro-inflammatory effects of platelets on the macrophage transcriptome was largely contact dependent. Altogether, our work shows that platelets interact with macrophages in the ischemic heart and polarize macrophages towards a pro-inflammatory phenotype in vitro, with potential implications for cardiac macrophage inflammatory activation after acute experimental MI.
• Junctional epithelial Plakoglobin facilitates intestinal inflammation by p38MAPK-dependent activation of the inflammasome. Kelm, Matthias; Burkard, Natalie; Hörner, Marius; Kollmann, Catherine; Otto, Christoph; Saravi, Babak; Seubert, Anna C.; Forchel, Friedrich; Kohler, Timo N.; Penner, Matthew; Hollfelder, Florian; Schmidt, Stefanie; Gerull, Brenda; Springer, Rebecca; Kampmeier, Stefanie; Rauschenberger, Vera; Deoghare, Nikita; Germer, Christoph-Thomas; Arampatzi, Panagiota; Kugelmann, Daniela; García-Ponce, Alexander; Waschke, Jens; Flemming, Sven; Kretzschmar, Kai; Schlegel, Nicolas (2025).

  Desmosomes play an underexplored role in intestinal homeostasis and are linked to the pathogenesis of inflammatory bowel diseases. We found a novel function of the desmosomal plaque protein Plakoglobin (JUP) in initiating the innate immune response to facilitate intestinal inflammation. Tissue samples from Crohn's disease (CD) patients revealed a loss of JUP, which was mirrored in a mouse model of dextran sodium sulfate-induced (DSS) colitis. Inducible intestinal epithelial-specific knock-out of Jup (iVilCreERT2Jupfl/fl) in mice resulted in increased submucosal infiltration of macrophages and neutrophils, along with activation of the inflammasome. This was paralleled by p38MAPK phosphorylation while loss intestinal epithelial barrier function was absent. In DSS-colitis, epithelial Jup-deficiency impaired recovery and enhanced IL23/IL17-signaling. Intestinal organoids lacking Jup demonstrated NLRP1 inflammasome activation, indicated by increased IL1β and IL18 levels, which was attenuated by p38MAPK inhibition. In silico analysis and co-immunoprecipitation confirmed a direct interaction between JUP and p38MAPK, revealing a regulatory mechanism where JUP limits inflammasome signaling in intestinal epithelial cells. These effects were blunted by NLRP1/3 inhibitor ADS032.. These findings identify JUP as a critical modulator of epithelial innate immunity in the gut. The loss of JUP in tissues from CD patients underscores its potential relevance in disease pathology.
• NGF stimulation alters the transcriptome and surface TrkB expression in axons of dorsal root ganglion neurons. Koch, Maximilian; Kshirsagar, Manas; Rawat, Ankita; Zare, Abdolhossein; Schlott, Felicitas; Bischler, Thorsten; Arampatzi, Panagiota; Briese, Michael; Sendtner, Michael (2025). 18 100194.

  Nerve growth factor (NGF) is released after injury from macrophages and other cell types and induces an inflammatory response in neurons, characterized by local subcellular reactions and transcriptomic modulation. NGF-induced axonal transcriptome modulation may be crucial for pain initiation and maintenance. To explore these acute modulations, we cultured dorsal root ganglion neurons in microfluidic chambers and stimulated the axons with NGF. We found that axonal levels of the Il7 transcript encoding interleukin-7 (IL-7) are increased after NGF stimulation, followed by IL-7 release from axons. In growth cones of sensory neurons, we also observed a reorganization of the ribosomal subunits 60S and 40S in response to NGF stimulation. In addition, a dynamic change in the spatio-temporal distribution of the Tropomyosin Kinase B (TrkB) receptor occurs at the plasma membrane of sensory neuron growth cones. TrkB is recruited from the endoplasmic reticulum (ER) leading to increased cell surface levels. De-novo synthesis of TrkB seems to be limited to somatic regions of sensory neurons. Thus, cytosolic mechanisms within distal regions of the sensory neurons may autonomously regulate signaling and translation in response to external NGF stimuli.
• Pollinator‐Promoting Interventions in European Urban Habitats—A Synthesis. Süle, Gabriella; Báldi, András; Kleijn, David; Steffan‐Dewenter, Ingolf; Venn, Stephen; Goulson, Dave; Dietzel, Simon; Muratet, Audrey; Cole, Lorna J.; Öckinger, Erik; Tzortzakaki, Olga; Banaszak‐Cibicka, Weronika; Betz, Oliver; Blackmore, Lorna M.; Dylewski, Łukasz; Fontaine, Benoît; Fournier, Bertrand; Geppert, Costanza; Griffiths‐Lee, Janine; Hawthorn, Catriona; Holzschuh, Andrea; Horák, Jakub; Horstmann, Svenja; Hoyle, Helen; Kati, Vassiliki; Kovács‐Hostyánszki, Anikó; Marini, Lorenzo; Michelot‐Antalik, Alice; Moretti, Marco; Norton, Briony A.; Phillips, Benjamin B.; Plećaš, Milan; Rada, Patrik; Sárospataki, Miklós; Schulze, Sonja; Shwartz, Assaf; Unterweger, Philipp; Szigeti, Viktor (2025). 28(8) e70189.
• Identifying the key components of a diet and lifestyle screener for people living with and beyond cancer: an e-Delphi study. Chaplin, Alice; Prohens, Lara; Wordsworth, Janna; Obrador-Hevia, Antònia; Guillot, Monica; Ricci-Cabello, Ignacio; Romaguera, Dora; Sesé, Albert (2025). 15(8) e097084-e097084.

  OBJECTIVES: There are currently no validated screeners that evaluate diet and lifestyle of people living with and beyond cancer (PLWBC). The purpose of this study was to reach a consensus among an international expert panel on the essential items to include in this type of instrument. DESIGN: A scientific committee developed the initial list of items, which were presented to an expert panel in a two-round-modified electronic Delphi. Panellists were asked to rate the adequacy, relevance and feasibility of self-reporting each item. Qualitative assessments were encouraged. SETTING: Four countries (Spain, UK, USA and Portugal). PARTICIPANTS: Experts working in a cancer-related health profession or cancer-related research were recruited. MAIN OUTCOME MEASURES: Items were initially categorised into seven domains (body composition, physical activity, diet, alcohol, smoking, sleep and psychosocial distress). A content validity index per item (CVI-i) and a scale-level CVI (S-CVI) were calculated (acceptable≥0.78). All items with a CVI-i≥0.78 were submitted to a final consensus meeting. RESULTS: A total of 108 items were proposed to the panel. In Round 1, 77 items were accepted, 10 items were excluded and 6 new items were proposed. During Round 2, 4 items were accepted and 19 were excluded. Diet and alcohol were merged into one domain. The final consensus meeting decided on 61 items categorised into six domains (S-CVI:0.94): body composition, physical activity, diet and alcohol, smoking, sleep and psychosocial distress. CONCLUSIONS: We identified the main items to be considered when developing a screener to evaluate diet and lifestyle in PLWBC in a clinical setting, and the results obtained will guide the content of the screener in the following validation study.
• Adversarial Training Improves Generalization Under Distribution Shifts in Bioacoustics. Heinrich, René; Rauch, Lukas; Sick, Bernhard; Scholz, Christoph (2025).
• Foundation Models for Bioacoustics -- a Comparative Review. Schwinger, Raphael; Zadeh, Paria Vali; Rauch, Lukas; Kurz, Mats; Hauschild, Tom; Lapp, Sam; Tomforde, Sven (2025).
• Common ground improves learning with conversational agents. Körner, Anita; Tolzin, Antonia; Janson, Andreas; Leimeister, Jan Marco; Rummer, Ralf (2025).

  Although conversational agents are successfully applied in teaching, it is largely unclear which communication principles should be employed to optimise learning. We examine the influence of common ground (i.e. shared knowledge on which to build during conversation) on learning. In an in-class experiment, students studied with one of two pedagogical conversational agents. The control version provided information without emphasising grounding, whereas the common ground version emphasised grounding, for example, by encouraging students to monitor and repair common ground. After the learning unit, students evaluated their learning experience and the pedagogical conversational agent, after which they were tested on the studied material. Students in the common ground (vs. the control) condition performed better in a post-study knowledge test and engaged longer with the pedagogical conversational agent. Thus, the common ground emphasis facilitated learning with a conversational agent, indicating that grounding principles should be incorporated when designing conversational agents.
• Nonastreda multimodal dataset for efficient tool wear state monitoring. Truchan, Hubert; Ahmadi, Zahra (2025). 62 111905.
• Nonastreda multimodal dataset for efficient tool wear state monitoring. Truchan, Hubert; Ahmadi, Zahra (2025). 62 111905.
• RLFuzz: Accelerating Hardware Fuzzing with Deep Reinforcement Learning. Götz, Raphael; Sendner, Christoph; Ruck, Nico; Rostami, Mohamadreza; Dmitrienko, Alexandra; Sadeghi, Ahmad-Reza (2025).

  Once hardware is manufactured, it becomes immutable, and any design flaws or vulnerabilities are permanent. Therefore, comprehensive testing of hardware designs is essential before production. However, the increasing complexity of modern processors makes static analysis and formal verification increasingly challenging. Fuzzing is a highly effective technique for detecting software vulnerabilities but adapting it to hardware presents unique challenges due to the fundamental differences between software and hardware. However, the current state-of-the-art in hardware fuzzing still has significant limitations, particularly in terms of performance, practicality, and the need for human intervention. To address these issues, we introduce RLFuzz, a novel hardware fuzzer that employs reinforcement learning to explore processors autonomously, achieving faster and more comprehensive coverage. Reinforcement learning enables the fuzzer to learn from its interactions with the processor without requiring labeled data, allowing it to more effectively select modifications for test cases and target previously unexplored areas. RLFuzz uses an asynchronous training mechanism that permits concurrent fuzzing and neural network training. To optimize RLFuzz, we performed an extensive evaluation of various deep Q-learning optimization techniques and hyper-parameters. We then tested the optimized fuzzer on three complex RISC-V cores-the Rocket core, CVA6, and BOOM-and compared its performance to a current hardware fuzzer, TheHuzz [20]. Our results show that RLFuzz achieved up to 1.77% higher coverage, and on average 2.35 times faster, and demonstrated a maximum speedup of up to 6.93 times. For branch coverage, the average speedup was 7.85 times, with a peak speedup of 92.98 times. Additionally, RLFuzz needed less time to complete 100,000 test cases and did not require any human intervention.
• The distribution of highly deleterious variants across human ancestry groups. Stolyarova, Anastasia; Coop, Graham; Przeworski, Molly (2025). 122(21) e2503857122.

  A major focus of human genetics is to identify severely pathogenic variants, both to help diagnose patients and as an entry point into understanding disease mechanisms. To that end, it is often argued that we should sequence large samples from every genetic ancestry group, to not miss variants at high frequency in one group but rare in another. Yet modeling predicts that highly deleterious alleles should be at similar frequencies across ancestry groups. Here, we show model predictions to be a good fit to the data for variants most likely to be highly deleterious, notably protein-coding disruptions. The implication is that we should expect such variants to occur at similarly low frequencies across ancestry groups. A major focus of human genetics is to map severe disease mutations. Increasingly, that goal is understood as requiring huge numbers of people to be sequenced from every broadly defined genetic ancestry group, so as not to miss “ancestry-specific variants.” Here, we consider whether this focus is warranted. We start from first principles considerations, based on models of mutation–drift-selection balance, which suggest that since severe disease mutations tend to be strongly deleterious, and thus evolutionarily young, they will be kept at relatively constant frequency through recurrent mutation. Therefore, highly pathogenic alleles should be shared identically by descent within extended families, not broad ancestry groups, and sequencing more people should yield similar numbers regardless of ancestry. We test the model predictions using gnomAD genetic ancestry groupings and show that they provide a good fit to the classes of variants most likely to be highly pathogenic, notably sets of loss of function alleles at strongly constrained genes. These findings clarify that strongly deleterious alleles will be found at comparable rates in people of all ancestries, and the information they provide about human biology is shared across ancestries.
• Nonlocality induces isometry and factorisation in holography. Banerjee, Souvik; Erdmenger, Johanna; Karl, Jonathan (2025). 112(2) L021902.
• Thermally robust and fragile surface states in the magnetic Weyl semimetal Co\($_\mathbf3$\)Sn\($_\mathbf2$\)S\($_\mathbf2$\). Lohani, Himanshu (2025). 112(4) 045140.
• Educational experiments with Particle Image Velocimetry in a small Prandtl water tunnel. Thielicke, William; Risius, Steffen (2025).

  A small water tunnel was designed as a table top experiment to visualize and measure basic fluid dynamic phenomena. The visualization of the flow by a laser light sheet and the measurement with Particle Image Velocimetry (PIV) proves to be very instructive for teaching high school and university students. Three basic fluid dynamic experiments are reported: the determination of the vortex shedding frequency of a cylinder (von-Karman vortex street), the measurement of circulation around a flat plate and the lift coefficient of a NACA profile. All three experiments show good agreement with theoretical expectations.
• Smoothed particle hydrodynamics for free-surface and multiphase flows: a review. Le Touzé, David; Colagrossi, Andrea (2025). 88(3) 037001.

  The smoothed particle hydrodynamics (SPH) method is expanding and is being applied to more and more fields, particularly in engineering. The majority of current SPH developments deal with free-surface and multiphase flows, especially for situations where geometrically complex interface configurations are involved. The present review article covers the last 25 years of development of the method to simulate such flows, discussing the related specific features of the method. A path is drawn to link the milestone articles on the topic, and the main related theoretical and numerical issues are investigated. In particular, several SPH schemes have been derived over the years, based on different assumptions. The main ones are presented and discussed in this review underlining the different contexts and the ways in which they were derived, resulting in similarities and differences. In addition, a summary is provided of the recent corrections proposed to increase the accuracy, stability and robustness of SPH schemes in the context of free-surface and multiphase flows. Future perspectives of development are identified, placing the method within the panorama of Computational Fluid Dynamics.
• 基于ConvLSTM与LiteFlowNet架构的粒子图像测速方法 Particle image velocimetry method based on ConvLSTM and LiteFlowNet architecture. LIU, Xin’ai; MENG, Juan; DU, Hai; LI, Zhiyuan (2025). 1023–1035.

  在粒子图像测速（Particle Image Velocimetry，PIV）中，神经网络方法在处理高速流动或复杂非线性流动时，常面临粒子位置变化迅速导致追踪匹配困难、提取的特征尺度单一、有效特征的提取能力不足等问题。针对这些问题，基于卷积长短期记忆网络（ConvLSTM）与LiteFlowNet结构提出了一种新的流场估计与动态粒子追踪增强模型LiteFlowNet-CL。所提方法首先通过强化的LiteFlowNet模型提升了对复杂流动模式的辨识与表征能力，随后结合ConvLSTM网络的时序建模优势，有效抑制了高速运动粒子在不同时间步长下的追踪误差，从而大幅度降低粒子图像特征丢失的几率。为验证所提模型的有效性，通过仿真粒子图像进行模型性能对比测试和消融实验。实验结果表明，改进后的速度场估计模型取得了0.100 4的均方根误差；相比LiteFlowNet经典光流估计模型，误差进一步降低了10.52%，与PIV领域广泛应用的LiteFlowNet-en高性能模型相比，误差进一步降低了1.463%。所提模型有效提升了粒子图像测速中复杂流场特征的捕捉能力，其误差精度可满足湍流分析的实验需求。本文为PIV算法优化提供了新的技术路径，对推动流体力学实验测量技术向更高时空分辨率发展具有应用价值。
• Exploring climate‐related gut microbiome variation in bumble bees: An experimental and observational perspective. Maihoff, Fabienne; Bofinger, Lukas; Brenzinger, Kristof; Keller, Alexander; Classen, Alice (2025). 106(3) e70066.
• Population-Based Evaluation for Dynamic Difficulty Adjustment in Repeated Rock-Paper-Scissors. Büttner, Johannes; Von Mammen, Sebastian (2025). 1–4.

  Dynamic Difficulty Adjustment (DDA) aims to personalize game challenge by adapting AI behavior to player skill, supporting engagement and sustained motivation. In this work, we present a population-based evaluation framework for DDA in Repeated Rock-Paper-Scissors. Agents are trained against a diverse population of rule-based bots to achieve a prescribed win-loss-draw distribution. Experimental results demonstrate that population-based RL enables agents to closely match target outcome distributions and generalize well to novel opponents, illustrating the promise of our approach for scalable, robust DDA.
• Designing for Flourishing: A Conceptual Model for Enhancing Older Adults’ Well-Being with Social Robots. Klier, Chantal; Lugrin, Birgit (2025). 12 1607373.
• Old Wine in New Bottles: Hard Euroscepticism in the 2024 European Parliament Elections. Hloušek, Vít; Havlík, Vratislav (2025). 32(2) 75–91.

  The article addresses the conceptualisation of hard Euroscepticism, which must reflect current crises and challenges facing European integration, such as the war in Ukraine. The conceptualisation of party-based Euroscepticism remains problematic, particularly in delineating a clear boundary between hard and soft variants. Szczerbiak and Taggart’s dichotomous typology is regarded as highly useful, offering two fundamental ideal types. However, its practical application proves more complex. Since Brexit, explicit calls to leave the EU have declined, supplanted by reformist narratives that blur traditional categories. Nonetheless, many political parties maintain fundamental objections to European integration, often concealed by strategic ambiguity. This article argues for the continued – but recontextualised – use of the ideal type of hard Euroscepticism, accounting for contextual and strategic variation and focusing not on the ‘essence’ of each type, but on the trajectory individual parties take in relation to the EU. It offers a theoretical and empirical framework for analysing manifestations of hard Euroscepticism in the 2024 European Parliament elections, drawing on both case studies and broader regional trends.
• Dedicated prostate DOI-TOF-PET based on the ProVision detection concept. Vo, Hong Phuc; Williams, Themistoklis; Doroud, Katayoun; Williams, Crispin; Rafecas, Magdalena (2025).
• Künstliche Intelligenz: Ein Netz aus systemischen Risiken. Kuhn, Johannes; Ketterer, Alexandra (2025).

  GPT-5 sorgt für Ernüchterung – und die Diskussionen über die Skalierbarkeit von KI und die hohen Investitionen in KI-Rechenzentren werden lauter. Was Expertinnen und Experten zum neuen Modell sagen und wo systemische Risiken des kreditfinanzierten KI-Infrastrukturbooms liegen.
• Towards sustainable insect pest management: A conceptual review using the example of pollen beetles in rapeseed. Fricke, Ute; Redlich, Sarah; Lucas-Barbosa, Dani; Steffan-Dewenter, Ingolf (2025). 197 107364.
• ‘I dropped a C-bomb into Tolstoy’: one man’s quest to translate War and Peace into ‘bogan Australian’ This article is more than 3 months old. Marsh, Walter (2025).
• Genealogical Analysis of Replicate Flower Colour Hybrid Zones in Antirrhinum. Pal, Arka; Shipilina, Daria; Le Moan, Alan; McNairn, Adrian J.; Grenier, Jennifer K.; Kucka, Marek; Coop, Graham; Chan, Yingguang Frank; Barton, Nicholas H.; Field, David L.; Stankowski, Sean (2025). n/a(n/a) e70067.

  ABSTRACT A major goal of speciation research is identifying loci that underpin barriers to gene flow. Population genomics takes a ‘bottom-up’ approach, scanning the genome for molecular signatures of processes that drive or maintain divergence. However, interpreting the ‘genomic landscape’ of speciation is complicated, because genome scans conflate multiple processes, most of which are not informative about gene flow. However, studying replicated population contrasts, including multiple incidences of secondary contact, can strengthen inferences. In this paper, we use linked-read sequencing (haplotagging), FST scans and genealogical methods to characterise the genomic landscape associated with replicate hybrid zone formation. We studied two flower colour varieties of the common snapdragon, Antirrhinum majus subspecies majus, that form secondary hybrid zones in multiple independent valleys in the Pyrenees. Consistent with past work, we found very low differentiation at one well-studied zone (Planoles). However, at a second zone (Avellanet), we found stronger differentiation and greater heterogeneity, which we argue is due to differences in the amount of introgression following secondary contact. Topology weighting of genealogical trees identified loci where haplotype diversity was associated with the two snapdragon varieties. Two of the strongest associations were at previously identified flower colour loci: Flavia, that affects yellow pigmentation, and Rosea/Eluta, two linked loci that affect magenta pigmentation. Preliminary analysis of coalescence times provides additional evidence for selective sweeps at these loci and barriers to gene flow. Our study highlights the impact of demographic history on the differentiation landscape, emphasising the need to distinguish between historical divergence and recent introgression.
• Performance of Multi-Hop FSO Systems Under Practical Conditions with Malaga Turbulence Channels and Pointing Errors. Trung, Ha Duyen (N. Meghanathan, ed.) (2025). 17(4) 41–57.

  Free Space Optical (FSO) communication offers a high-capacity solution for wireless networks, but its performance is severely degraded by atmospheric turbulence and pointing errors, particularly in multi-hop configurations. This paper investigates the performance of multi-hop FSO systems operating over Malaga fading channels, incorporating pointing errors and 32-QAM modulation under practical conditions. We derive analytical expressions and conduct Monte Carlo simulations to evaluate key performance metrics, including Bit Error Rate (BER), Symbol Error Rate (SER), and ergodic channel capacity, as functions of hop count and turbulence severity (weak, moderate, and strong). Simulation results show that BER and SER increase exponentially with hops, reaching 10−3 to 10−2 at 5 hops under strong turbulence, while capacity decreases, dropping below 3 bits/s/Hz under similar conditions. The study highlights the tradeoffs between hop count, turbulence conditions, and system reliability, offering design guidelines for optimizing multi-hop FSO networks. These findings underscore the importance of turbulence mitigation and pointing error compensation to achieve reliable high-capacity FSO communication in real-world deployments.
• August 2025 Top read articles in International Journal of Database Management Systems ( IJDMS ). ijdms (2025).

  The International Journal of Database Management Systems (IJDMS) is a bi monthly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the database management systems & its applications. The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on understanding Modern developments in this field, and establishing new collaborations in these areas.
• Specific Immersive Competence in VR-Based Assessments: Development, Psychometric Evaluation and Associations with Medical Performance. Schreiner, Verena; Joy, Backhaus; Marco, Lindner; Melina, Heinisch; Sarah, König; Sebastian, Oberdörfer; Tobias, Mühling (2025). 10/08/2025:82136

  Background: Virtual reality (VR) is increasingly used in medical education for training and examination purposes, yet learners' performance in VR-based assessments may be influenced by more than clinical competence alone. Immersive competence (IC) has been proposed as a relevant factor in VR-based performance assessment. While general IC captures application-independent VR interaction skills, domain-specific applications may require an additional construct - specific IC - reflecting situational interaction proficiency. Objective: This pilot study aimed (1) to examine the psychometric properties of a newly developed in situ checklist for assessing specific IC, (2) to investigate the relationship between specific and general IC as well as related human abilities and characteristics, and (3) to explore associations between both IC measures and medical performance in a VR-based OSCE station. Methods: This observational follow-up study was conducted with 21 final-year medical students who had previously completed a curricular OSCE including a VR-based emergency medicine station. General IC was assessed using the VR competence app, and specific IC using a checklist embedded in the original VR simulation. Additional measures included self-reported technological affinity, spatial ability, and OSCE performance scores. Item difficulty, item-total correlations, and internal consistency were calculated for the specific IC checklist. Pearson’s r was used to examine associations among variables. Results: The final 13-item specific IC checklist demonstrated acceptable internal consistency (Cronbach’s α = .79) and balanced item difficulty (mean P = 0.56). Specific IC showed a strong correlation with general IC (r = 0.56, p = .008) and with prior 3D application experience (r = 0.57, p = .007), but no relevant association with spatial ability. Both general and specific IC correlated moderately with VR-OSCE performance (r = 0.41, p = .06 and r = 0.37, p = .09, respectively), but neither was related to overall analog OSCE performance. Conclusions: Specific IC appears to be a psychometrically accessible and context-sensitive dimension of VR user readiness. The proposed in situ approach offers a feasible and scalable method to assess this construct within domain-specific VR applications. While correlations with medical performance were limited in this small sample, the findings underscore the importance of considering IC in VR-based high-stakes assessments to support fairness and validity.
• Solving Random Planted CSPs below the nk/2. Basu, Arpon; Hsieh, Jun-Ting; Lin, Andrew D.; Manohar, Peter (2025).
• Hair‐based minimally invasive barcoding of bumblebees. Rongstock, Lydia; Schardt, Leonie; Maihoff, Fabienne; Grünewald, Bernd; Bálint, Miklós (2024). 18(2) 127–139.
• Tuning Spatial Distributions of Selection Pressure to Suppress Emergence of Resistance. Tunstall, Thomas; Madgwick, Philip G.; Kanitz, Ricardo; Möbius, Wolfram (2024).

  Control measures such as insecticides or antimicrobials are used to contain biological agents such as pathogenic bacteria and vectors of human and plant diseases, respectively. Following control measure application, a resistant subpopulation may eventually rise to such frequency that the control measure will be rendered ineffective: The timescale over which this occurs is the textquotelefteffective lifetimetextquoteright of the control measure. Prolonging this timescale relaxes urgency at which novel control measure needs to be developed. Spatial heterogeneity in control measure application can influence the rate at which resistance to the control measure evolves; in the agricultural context, this fact is exploited by distributing insecticides in mosaics across cropping regions in order to slow the rate of resistance evolution.Contemporary and historical modeling practices, which aim to inform agricultural practices, often employ assumptions which squeeze out the impact of the spatio-temporal heterogeneity endemic to nature. In this paper, we present a minimal model of continuous dispersal and spatio-temporal heterogeneity in selection pressure distribution which exhibits a novel dynamic: The spatial distribution of selection pressure may be tuned in order to minimize the initial rate at which resistance evolves, thus increasing the effective lifetime of a pesticide.Author summary There are many contexts in which humans apply control measures to biological agents: pesticides are applied in fields to kill the pests that damage crops, mosquito nests are distributed to prevent the spread of malaria, and cancer drugs are applied to kill off tumors in humans. These control measures are examples of textquoteleftselection pressurestextquoteright, which select against strains which are susceptible to them. If a mutation occurs which confers resistance, the control agent will select for the resistant strain, thus reducing the efficacy of the control agent as the frequency of resistance increases in the population. This necessitates more of the control agent to be applied, or for a novel control agent to be developed. The former may have unintended consequences on the local environment, and the latter is expensive and time-intensive. It is preferable to carefully tune how the control agent is applied - perhaps instead of one massive compact region of control measure application, it is better to apply the control measure over multiple smaller regions? Here, we use a toy model of motile organisms to demonstrate that an optimal distribution exists for a variety of scenarios.Competing Interest StatementThe authors have declared no competing interest.
• Towards an Empirical Study on Transient Phases of Microservice Applications Rohwer, Ivo; Straesser, Martin; Lubas, Yannik; Kounev, Samuel (2024).
• Towards an Empirical Study on Transient Phases of Microservice Applications Rohwer, Ivo; Straesser, Martin; Lubas, Yannik; Kounev, Samuel (2024).
• Towards an Empirical Study on Transient Phases of Microservice Applications Rohwer, Ivo; Straesser, Martin; Lubas, Yannik; Kounev, Samuel (2024).
• Numerical modeling for mesh-independent simulations of spray atomization. Technical Report (PhD dissertation), Han, Austin; Desjardins, Olivier (2024).

  Multiphase flows involving fluid-fluid interfaces with surface tension underlie many processes of scientific and industrial importance. A major challenge associated with the numerical modeling of these flows comes from their multi-scale behavior, where coexisting drops, bubbles, and films can vary in size by several orders of magnitude, requiring computationally prohibitive mesh resolutions. Furthermore, current methods for representing fluid interfaces rely on mesh-size-dependent numerical errors to perform topology changes, such as breakup and coalescence. This dissertation presents various numerical methods to drastically increase the accuracy of large-scale interfacial flow simulations performed with relatively coarse mesh resolutions and presents several models to account for subgrid-scale interfacial physics. Focus will be directed towards applications in spray atomization, where a large liquid structure fragments into many smaller droplets. First, the accurate calculation of surface tension forces is addressed through advances in methods for the estimation of interfacial curvature. To decouple the breakup of liquid films from the underlying mesh size, a novel two-plane method for the representation of subgrid-thickness films is then discussed. Next, a modeling framework is proposed to predict the formation of small droplets from the breakup of these liquid films, including their diameters and initial velocities. Finally, the proposed framework is validated with a canonical drop breakup problem, where the models produce drop sizes and velocities in quantitative agreement with experimental results. The proposed methods will facilitate the efficient subgrid-scale modeling of spray formation for engineering applications.
• Towards an Empirical Study on Transient Phases of Microservice Applications Rohwer, Ivo; Straesser, Martin; Lubas, Yannik; Kounev, Samuel (2024).
• It’s about (taking up) space: Discreteness of individuals and the strength of spatial coexistence mechanisms. Ellner, Stephen P.; Snyder, Robin E.; Adler, Peter B.; Hernández, Christina M.; Hooker, Giles (2024). 105(11) e4404.

  Abstract One strand of modern coexistence theory (MCT) partitions invader growth rates (IGR) to quantify how different mechanisms contribute to species coexistence, highlighting fluctuation-dependent mechanisms. A general conclusion from the classical analytic MCT theory is that coexistence mechanisms relying on temporal variation (such as the temporal storage effect) are generally less effective at promoting coexistence than mechanisms relying on spatial or spatiotemporal variation (primarily growth-density covariance). However, the analytic theory assumes continuous population density, and IGRs are calculated for infinitesimally rare invaders that have infinite time to find their preferred habitat and regrow, without ever experiencing intraspecific competition. Here we ask if the disparity between spatial and temporal mechanisms persists when individuals are, instead, discrete and occupy finite amounts of space. We present a simulation-based approach to quantifying IGRs in this situation, building on our previous approach for spatially non-varying habitats. As expected, we found that spatial mechanisms are weakened; unexpectedly, the contribution to IGR from growth-density covariance could even become negative, opposing coexistence. We also found shifts in which demographic parameters had the largest effect on the strength of spatial coexistence mechanisms. Our substantive conclusions are statements about one model, across parameter ranges that we subjectively considered realistic. Using the methods developed here, effects of individual discreteness should be explored theoretically across a broader range of conditions, and in models parameterized from empirical data on real communities.
• Enhancement of PIV measurements via physics-informed neural networks. Hasanuzzaman, Gazi; Eivazi, Hamidreza; Merbold, Sebastian; Egbers, Christoph; Vinuesa, Ricardo (2023). 34(4) 044002.

  Physics-informed neural networks (PINN) are machine-learning methods that have been proved to be very successful and effective for solving governing equations of fluid flow. In this work we develop a robust and efficient model within this framework and apply it to a series of two-dimensional three-component stereo particle-image velocimetry (PIV) datasets, to reconstruct the mean velocity field and correct measurements errors in the data. Within this framework, the PINNs-based model solves the Reynolds-averaged-Navier–Stokes equations for zero-pressure-gradient turbulent boundary layer (ZPGTBL) without a prior assumption and only taking the data at the PIV domain boundaries. The turbulent boundary layer (TBL) data has different flow conditions upstream of the measurement location due to the effect of an applied flow control via uniform blowing. The developed PINN model is very robust, adaptable and independent of the upstream flow conditions due to different rates of wall-normal blowing while predicting the mean velocity quantities simultaneously. Hence, this approach enables improving the mean-flow quantities by reducing errors in the PIV data. For comparison, a similar analysis has been applied to numerical data obtained from a spatially-developing ZPGTBL and an adverse-pressure-gradient TBL over a NACA4412 airfoil geometry. The PINNs-predicted results have less than 1% error in the streamwise velocity and are in excellent agreement with the reference data. This shows that PINNs has potential applicability to shear-driven turbulent flows with different flow histories, which includes experiments and numerical simulations for predicting high-fidelity data.
• Genetic similarity versus genetic ancestry groups as sample descriptors in human genetics. Coop, Graham (2023).
• 粒子图像测速技术：从实验室到工业应用的进展（特邀）. Bilal Muhammad, Muhammad Bilal; TIAN Zhenyu 田振玉 (2023). 52(3) 0352103.

  粒子图像测速（PIV）已成为测量流体流动速度场的重要实验技术。该方法产生瞬时流型的定量表示，通常用于帮助构建复杂流动的现象学模型和数值模拟验证。PIV分析可广泛用于实验流体力学等多个研究领域。两步处理法，即自相关和互相关，已被用于检查时空流演化，可以实现作为空间分辨率函数的涡度测量和精度估计。PIV的发展与测量流场的复杂性和难度逐渐增加紧密相关。用于测量的PIV技术发展迅速，并呈现出新的趋势，主要体现在立体PIV、断层PIV、大型PIV、微型PIV、3D PIV、行人PIV以及使用高时间/空间分辨率设备。PIV在医学研究、能源燃料、燃烧、流场测量、实时过程监测、结构变形、灌溉、声学、地质学、海洋学、水资源、林业、人群监测和采矿矿物加工等各种研究领域有着广泛的应用。本文对实验室PIV发展进行全面概述，通过在工业过程和日常生活中采用PIV进行实时监控，讨论了PIV如何以精确的时间分辨率和特殊分辨率取代现有的分析成像技术。此外，还综合比较了数值模拟和目前可用的PIV分析技术。
• Das Büro als sozialer Ort: Zusammenarbeit in hybriden Arbeitswelten. Entgelmeier, Ines; Meyer, Sophie-Charlotte; Tisch, Anita; Backhaus, Nils (2023). 32(2) 111–132.

  Viele Bürobeschäftigte haben seit der Covid-19-Pandemie die Möglichkeit, hybrid, also im Wechsel zu Hause und im Büro, zu arbeiten. Die Zusammenarbeit mit Kolleginnen und Kollegen wird dadurch vermehrt ins Virtuelle verlagert. Hierdurch kann sich nicht nur die inhaltliche Zusammenarbeit, sondern können sich auch soziale Beziehungen zwischen Beschäftigten verändern. Auf Basis der BAuA-Arbeitszeitbefragung 2019 und 2021 wird untersucht, ob es einen Zusammenhang zwischen dem Anteil des Arbeitens von zu Hause und der Bewertung der kollegialen Zusammenarbeit gibt. Hierbei unterscheiden wir zwischen formeller, inhaltlicher Zusammenarbeit und informeller, persönlicher Zusammenarbeit. Die Ergebnisse zeigen, dass Bürobeschäftigte mit zunehmendem Anteil der Arbeit von zu Hause sowohl die formelle als auch die informelle Zusammenarbeit schlechter bewerten. Dabei wird insbesondere die formelle Zusammenarbeit 2021 jedoch besser bewertet als noch 2019. Erfahrungen während der Covid-19-Pandemie haben hier möglicherweise zu Lerneffekten in der virtuellen Zusammenarbeit geführt.
• ANALYSIS AND FORECASTING OF ELECTRICITY DEMAND IN DAVAO DEL SUR, PHILIPPINES. Technical Report (PhD dissertation), Parreño, Samuel John E. (2022, May).
• Numerical methods and modelling approaches. Michaelides, Efstathios E.; Sommerfeld, Martin; van Wachem, Berend (2022). (Third ) 239–338.

  The numerical calculation of single-phase flows may be broadly separated into three classes depending on their spatial resolution, as illustrated in Figure 8.1. An introduction to these methods may be found in Ferziger and Peric (2002) together with details about discretization schemes and solution procedures. The first approach, direct numerical simulations (DNS) in principle resolves all relevant flow scales down to the Kolmogorov scales (i.e. the turbulent dissipation scales). Consequently, the numerical grid should be smaller than these scales to ensure proper resolution. This, however, implies that the size of the computational domain is limited due to the limited number of numerical control volumes that can be handled by today’s computers. Consequently, DNS is not able to resolve the entire spectrum of vortex scales or wave numbers, and hence, there is a cutoff at larger scales. Moreover, the ratio of macro-scale vortices to the Kolmogorov scale is proportional to Re¾. As a result, the flow Reynolds number considered in DNS has a limitation too. Typically, the maximum Re is between 5,000 and 10,000. Therefore, the application of DNS is limited to simple flow conditions, such as homogeneous isotropic turbulence, shear flows, and channel flows. Nevertheless, the DNS method is very helpful in analyzing and understanding basic phenomena in turbulence research.
• lncRNAMalat1and miR-26 cooperate in the regulation of neuronal progenitor cell proliferation and differentiation. Was, Nina; Sauer, Mark; Fischer, Utz; Becker, Matthias (2022). 29(1) 69–81.
• Flow visualization: state-of-the-art development of micro-particle image velocimetry. Etminan, Amin; Muzychka, Yuri S; Pope, Kevin; Nyantekyi-Kwakye, Baafour (2022). 33(9) 092002.

  Experimental flow visualization is a valuable tool for analyzing microfluidics and nanofluidics in a wide variety of applications. Since the late 1990s, considerable advances in optical methods and image postprocessing techniques have improved direct optical measurements, resulting in an accurate qualitative and quantitative understanding of transport phenomena in lab-on-a-chip capillaries. In this study, a comparison of different optical measurement techniques is presented. The state-of-the-art development of particle image velocimetry (PIV) to date, particularly in microscale applications, is reviewed here in detail. This study reviews novel approaches for estimating velocity field measurements with high precision within interrogation windows. Different regularization terms are discussed to demonstrate their capability for particle displacement optimization. The discussion shows how single- and multi-camera optical techniques provide two-dimensional and three-component velocity fields. The performance of each method is compared by highlighting its advantages and limitations. Finally, the feasibility of micro resolution PIV in bioapplications is overviewed.
• Ratgeber berufsbegleitende Promotion : Eine Entscheidungshilfe Staab, Thomas; Matusiewicz, David in UTB (2022). (Vol. 5845) Budrich.
• A Review of the Recent PIV Studies <br/>—From the Basics to the Hybridization with CFD. Yamamoto, Fujio; Ishikawa, Masaaki (2022). 10(04) 117–147.

  The purpose of this article is to review recent PIV Studies from the basic to hybrid analysis, focusing on explaining epoch-making development of PIV. The overwhelming advantage of PIV over other velocity measurement methods is that it enables instantaneous and simultaneous velocity measurement of whole flow fields. We roughly classify PIV development and/or progress into the following five categories; A) Basics of PIV and post-processing. B) Simultaneous measurement of velocity and temperature, and 3D-PIV. C) Application to multiphase turbulent flows. D) Application to fluid machinery. E) Hybridization of PIV and CFD. This paper introduces the epoch-making research results from papers published in international journals as milestones related to (A) to (E), and concludes with additional forecast of future development of PIV research.
• Deep learning based on PINN for solving 2 D0F vortex induced vibration of cylinder with high Reynolds number. Cheng, Chen; Xu, Peng-Fei; Li, Yong-Zheng; Zhang, Guang-Tao (2021).

  Vortex-induced vibration (VIV) exists widely in natural and industrial fields. The main approaches for solving VIV problems are numerical simulations and experimental methods. However, experiment methods are difficult to obtain the whole flow field information and also high-cost while numerical simulation is extraordinary time-consuming and limited in low Reynolds number and simple geometric configuration. In addition, numerical simulations are difficult to handle the moving mesh technique. In this paper, physics informed neural network (PINN) is proposed to solve the VIV and wake-induced vibration (WIV) of cylinder with high Reynolds number. Compared to tradition data-driven neural network, the Reynolds Average Navier-Stokes (RANS) equation, by implanting an additional turbulent eddy viscosity, coupled with structure's dynamic motion equation are also embedded into the loss function. Training and validation data is obtained by computational fluid dynamic (CFD) technique. Three scenarios are proposed to validate the performance of PINN in solving VIV and WIV of cylinders. In the first place, the stiffness parameter and damping parameter are calculated via limited force data and displacement data; secondly, the flow field and lifting force/drag force are inferred by scattered velocity information; eventually, the displacement can be directly predicted only through lifting forces and drag forces based on LSTM. Results demonstrate that,compared with traditional neural network, PINN method is more effective in inferring and re-constructing the unknown parameters and flow field with high Reynolds number under VIV and WIV circumstances.
• A critical assessment of the potential and limitations of physicochemical analysis to advance knowledge on Levantine rock art. Domingo Sanz, Inés; Vendrell, Marius; Chieli, Annalisa (2021). 572 24–40.
• What is ancestry?. Mathieson, Iain; Scally, Aylwyn (2020). 16(3) 1–6.

  Ancestry connects genetics and society in fundamental ways. For many people it has cultural, religious or even political significance, and can play a key role in shaping personal and public identities. People’s desire to discover their own ancestry drives the multibillion-dollar genealogy industry, which has grown rapidly in the era of consumer genomics. Companies such as 23andMe and Ancestry now claim tens of millions of customers worldwide. In parallel, our scientific understanding of the human past is being transformed by studies of ancient and modern genetic data, which allow us to track changes in ancestry over space and time. Sophisticated methods have been developed to infer and visualise these relationships. Thus, it seems that both scientists and the wider public are learning more and more about ancestry, and there is an optimistic sense that genetic data provide an exhaustive repository of ancestral information. However, although frequently discussed, ancestry itself is rarely defined. We argue that this reflects widespread underlying confusion about what it means in different contexts and what genetic data can really tell us. This leads to miscommunication between researchers in different fields, and leaves customers open to spurious claims about consumer genomics products and overinterpretation of individual results. In wider usage, the terms ancestry and ancestors often indicate a general connection to people or things in the past. But in a genetic context they have a more specific meaning: your ancestors are the individuals from whom you are biologically descended and ancestry is information about them and their genetic relationship to you. Even here however, confusion arises from the way that ancestry is presented and discussed. Rather than emphasising its complex structure, results are often simplified in terms of discrete categories. While convenient and sometimes useful, ultimately this is misleading about the nature of ancestry. These labels can also impose contemporary political or cultural divisions which may be misrepresentative of ancestral relationships. Another source of confusion is that three distinct concepts–genealogical ancestry, genetic ancestry, and genetic similarity–are frequently conflated. We discuss them in turn, but note that only the first two are explicitly forms of ancestry, and that genetic data are surprisingly uninformative about either of them. Consequently, most statements about ancestry are really statements about genetic similarity, which has a complex relationship with ancestry, and can only be related to it by making assumptions about human demography whose validity is uncertain and difficult to test.
• Surface modification of ammonium nitrate by coating with surfactant materials to reduce hygroscopicity. Elzaki, Baha I.; Zhang, Yue Jun (2019). 15(4) 615–620.

  Ammonium nitrate (AN) is promising oxidizer in green propellants. In this work, the physical coating method was improved to modify the surface of ammonium nitrate particles with different surfactant materials to reduce hygroscopicity. Cetylalcohol, stearic acid, stearyl alcohol, palmic acid, lauric acid, stearsmide, tetradecylamine, dodecylamine, and tetradecanol were used as coating surfactant agents. The hygroscopicity was tested for ammonium nitrate with and without coating. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) were used to characterize the surface of coated and uncoated ammonium nitrate. The mass ratio of coating layer and decline of absorption rate of ammonium nitrate coated by cetylalcohol were 1.00%, and 28.40%, respectively. The results indicate that coating with cetylalcohol surfactant have advantages over the other surfactants in term of low mass ratio of coating layer, and high decline of moisture absorption rate. Thus, cetylalcohol would be a promising coating surfactant material for ammonium nitrate. The idea and approach presented in this study have potential to made hydrophobic layer on the surface of particles to reduce hygroscopicity of AN, and also help the researcher to improving anti-hygroscopicity of ammonium salts.
• Perry’s Chemical Engineers’ Handbook Green, Don W.; Southard, Marylee Z. (2019). (Ninth ) McGraw-Hill Education, New York.

  Up-to-Date Coverage of All Chemical Engineering Topics―from the Fundamentals to the State of the Art Now in its 85th Anniversary Edition, this industry-standard resource has equipped generations of engineers and chemists with vital information, data, and insights. Thoroughly revised to reflect the latest technological advances and processes, Perry's Chemical Engineers' Handbook, Ninth Edition, provides unsurpassed coverage of every aspect of chemical engineering. You will get comprehensive details on chemical processes, reactor modeling, biological processes, biochemical and membrane separation, process and chemical plant safety, and much more. This fully updated edition covers: Unit Conversion Factors and Symbols • Physical and Chemical Data including Prediction and Correlation of Physical Properties • Mathematics including Differential and Integral Calculus, Statistics , Optimization • Thermodynamics • Heat and Mass Transfer • Fluid and Particle Dynamics *Reaction Kinetics • Process Control and Instrumentation• Process Economics • Transport and Storage of Fluids • Heat Transfer Operations and Equipment • Psychrometry, Evaporative Cooling, and Solids Drying • Distillation • Gas Absorption and Gas-Liquid System Design • Liquid-Liquid Extraction Operations and Equipment • Adsorption and Ion Exchange • Gas-Solid Operations and Equipment • Liquid-Solid Operations and Equipment • Solid-Solid Operations and Equipment •Chemical Reactors • Bio-based Reactions and Processing • Waste Management including Air ,Wastewater and Solid Waste Management* Process Safety including Inherently Safer Design • Energy Resources, Conversion and Utilization* Materials of Construction
• Diplomatičke isprave Općine Lokva Rogoznica. Marušić, Bartul (2019). (5) 79–114.
• Atomization and Sprays Lefebvre, Arthur H.; McDonell, Vincent G. in Combustion (2017). Taylor & Francis, CRC Press, Boca Raton.

  The second edition of this long-time bestseller provides a framework for designing and understanding sprays for a wide array of engineering applications. The text contains correlations and design tools that can be easily understood and used in relating the design of atomizers to the resulting spray behavior. Written to be accessible to readers with a modest technical background, the emphasis is on application rather than in-depth theory. Numerous examples are provided to serve as starting points for using the information in the book. Overall, this is a thoroughly updated edition that still retains the practical focus and readability of the original work by Arthur Lefebvre.
• Die Bibliothek Fleischmann in Tübingen – die Tübinger Juristenfakultät auf Schnäppchenjagd?. Schneider, Sebastian (2016). 75 277–290.
• A method for calculating probabilities of fitness consequences for point mutations across the human genome. Gulko, Brad; Hubisz, Melissa J; Gronau, Ilan; Siepel, Adam (2015). 47(3) 276–283.

  We describe a new computational method for estimating the probability that a point mutation at each position in a genome will influence fitness. These 'fitness consequence' (fitCons) scores serve as evolution-based measures of potential genomic function. Our approach is to cluster genomic positions into groups exhibiting distinct 'fingerprints' on the basis of high-throughput functional genomic data, then to estimate a probability of fitness consequences for each group from associated patterns of genetic polymorphism and divergence. We have generated fitCons scores for three human cell types on the basis of public data from ENCODE. In comparison with conventional conservation scores, fitCons scores show considerably improved prediction power for cis regulatory elements. In addition, fitCons scores indicate that 4.2-7.5% of nucleotides in the human genome have influenced fitness since the human-chimpanzee divergence, and they suggest that recent evolutionary turnover has had limited impact on the functional content of the genome.
• The distribution of deleterious genetic variation in human populations. Lohmueller, Kirk E (2014). 29 139–146.

  Population genetic studies suggest that most amino-acid changing mutations are deleterious. Such mutations are of tremendous interest in human population genetics as they are important for the evolutionary process and may contribute risk to common disease. Genomic studies over the past 5 years have documented differences across populations in the number of heterozygous deleterious genotypes, number of homozygous derived deleterious genotypes, number of deleterious segregating sites and proportion of sites that are potentially deleterious. These differences have been attributed to population history affecting the ability of natural selection to remove deleterious variants from the population. However, recent studies have suggested that the genetic load is the same across populations and that the efficacy of natural selection has not differed across human populations. Here I show that these observations are not incompatible with each other and that the apparent differences are due to examining different features of the genetic data and differing definitions of terms.
• Improving the discovery of IXP peering links through passive BGP measurements. Giotsas, Vasileios; Zhou, Shi (2013). 3249–3254.
• Handbook of Atomization and Sprays : Theory and Applications Ashgriz, N. (2011). Springer, New York.

  Atomization and sprays are used in a wide range of industries: mechanical, chemical, aerospace, and civil engineering; material science and metallurgy; food; pharmaceutical, forestry, environmental protection; medicine; agriculture; meteorology and others. Some specific applications are spray combustion in furnaces, gas turbines and rockets, spray drying and cooling, air conditioning, powdered metallurgy, spray painting and coating, inhalation therapy, and many others. The Handbook of Atomization and Sprays will bring together the fundamental and applied material from all fields into one comprehensive source. Subject areas included in the reference are droplets, theoretical models and numerical simulations, phase Doppler particle analysis, applications, devices and more.
• Multiphase Flow Handbook Crowe, Clayton T. (2006). CRC, Boca Raton, Florida.
• How to extract BGP peering information from the internet routing registry. Battista, Giuseppe Di; Refice, Tiziana; Rimondini, Massimo in MineNet ’06 (2006). 317–322.

  We describe an on-line service, and its underlying methodology, designed to extract BGP peerings from the Internet Routing Registry. Both the method and the service are based on: a consistency manager for integrating information across different registries, an RPSL analyzer that extracts peering specifications from RPSL objects, and a peering classifier that aims at understanding to what extent such peering specifications actually contribute to fully determine a peering. A peering graph is built with different levels of confidence. We compare the effectiveness of our method with the state of the art. The comparison puts in evidence the quality of the proposed method.
• Comparison of CFD and PIV Data for the Airflow in an Aero-Engine Bearing Chamber. Lee, C. W.; Palma, P. C.; Simmons, K.; Pickering, S. J. (2004). (Vol. 2) 97–105.

  Investigations into the single-phase velocity field of a model aero-engine bearing chamber are presented. Adequately resolving the airflow field is important to subsequent computational modelling of two-phase fluid transport and heat transfer characteristics. A specially designed test rig, representing the features of a Rolls-Royce Trent series aero-engine bearing chamber, was constructed. Experimental data for the airflow field was obtained using particle image velocimetry (PIV). The results show a strong influence of shaft rotation and chamber geometry on the flow features within the bearing chamber. A computational fluid dynamics (CFD) simulation was carried out using the commercial CFD code FLUENT 6. Flow features were adequately modelled, showing the features of secondary velocities. Turbulence modelling using the differential Reynolds stress (RSM) model shows good agreement with the experimental data.
• Comparison of Computational Fluid Dynamics and Particle Image Velocimetry Data for the Airflow in an Aeroengine Bearing Chamber. Lee, C. W.; Palma, P. C.; Simmons, K.; Pickering, S. J. (2004). 127(4) 697–703.

  Investigations into the single-phase velocity field of a model aeroengine bearing chamber are presented. Adequately resolving the airflow field is important to subsequent computational modeling of two-phase fluid transport and heat transfer characteristics. A specially designed test rig, representing the features of a Rolls Royce Trent series aeroengine bearing chamber, was constructed. Experimental data for the airflow field was obtained using particle image velocimetry (PIV). The results show a strong influence of shaft rotation and chamber geometry on the flow features within the bearing chamber. A computational fluid dynamics (CFD) simulation was carried out using the commercial CFD code FLUENT 6. Flow features were adequately modeled, showing the features of secondary velocities. Turbulence modeling using the differential Reynolds stress (RSM) model shows good agreement with the experimental data.
• Breakup of Round Nonturbulent Liquid Jets in Gaseous Crossflow. Sallam, K. A.; Aalburg, C.; Faeth, G. M. (2004). 42(12) 2529–2540.
• Particle Image Velocimetry in Rotating Couette Flow: Oil and Air Flow in the HP-IP Bearing Chamber. Technical Report (UTC-FF03), Palma, P. C. (2003).
• Breakup of round nonturbulent liquid jets in gaseous crossflows. Sallam, Khaled; Aalburg, Christian; Faeth, Gerard in Aerospace Sciences Meetings (2003).
• Estimating Allele Age. Slatkin, Montgomery; Rannala, Bruce (2000). 1(Volume 1, 2000) 225–249.

  The age of an allele can be estimated both from genetic variation among different copies (intra-allelic variation) and from its frequency. Estimates based on intra-allelic variation follow from the exponential decay of linkage disequilibrium because of recombination and mutation. The confidence interval depends both on the uncertainty in recombination and mutation rates and on randomness of the genealogy of chromosomes that carry the allele (the intra-allelic genealogy). Several approximate methods to account for variation in the intra-allelic genealogy have been derived. Allele frequency alone also provides an estimate of age. Estimates based on frequency and on intra-allelic variability can be combined to provide a more accurate estimate or can be contrasted to show that an allele has been subject to natural selection. These methods have been applied to numerous cases, including alleles associated with cystic fibrosis, idiopathic torsion dystonia, and resistance to infection by HIV. We emphasize that estimates of allele age depend on assumptions about demographic history and natural selection.
• Simulating surface tension with smoothed particle hydrodynamics. Morris, Joseph P. (2000). 33(3) 333–353.

  A method for simulating two-phase flows including surface tension is presented. The approach is based upon smoothed particle hydrodynamics (SPH). The fully Lagrangian nature of SPH maintains sharp fluid?fluid interfaces without employing high-order advection schemes or explicit interface reconstruction. Several possible implementations of surface tension force are suggested and compared. The numerical stability of the method is investigated and optimal choices for numerical parameters are identified. Comparisons with a grid-based volume of fluid method for two-dimensional flows are excellent. The methods presented here apply to problems involving interfaces of arbitrary shape undergoing fragmentation and coalescence within a two-phase system and readily extend to three-dimensional problems. Boundary conditions at a solid surface, high viscosity and density ratios, and the simulation of free-surface flows are not addressed. Copyright ? 2000 John Wiley & Sons, Ltd.
• Primary breakup of nonturbulent round liquid jets in gas crossflows. Mazallon, J.; Dai, Z.; Faeth, G. M. (1999). 9(3) 291–312.

  An experimental investigation of primary breakup of nonturbulent round liquid jets in gas crossflows is described. Pulsed shadowgraph measurements of jet primary breakup regimes, jet deformation properties, time of onset of primary breakup, and liquid column and liquid surface disturbance wavelengths were obtained for air crossflows at normal temperature and pressure, the test range included crossflow Weber numbers of 0−200, liquid jet Weber numbers of 0−1,600,000, liquid jet Reynolds numbers of 0−800,000, liquid/gas momentum ratios of 100−8000, liquid/gas density ratios of 700−1100, and Ohnesorge numbers of 0.00006−0.3. The results suggest qualitative similarities between the primary breakup of nonturbulent round liquid jets in crossflows and the secondary breakup of drops, with relatively little effect of the liquid/gas momentum ratio over the present test range. Effects of liquid viscosity were also small for Ohnesorge numbers less than 0.1, but larger Ohnesorge numbers modified primary breakup because unusually long ligaments developed that also are seen during the secondary breakup of drops.
• Genealogies and Geography. Barton, N H; Wilson, I P. H. Harvey, A. J. Leigh Brown, J. Maynard Smith (eds.) (1995).
• Liquid Atomization Bayvel, L. P.; Orzechowski, Z. in Combustion: An International Series (1993). (First ) Taylor & Francis, Washington, DC.

  Covering the basics of liquid atomization, this book familiarizes readers with the physical processes of liquid atomization, the main types of atomizers and their design, measurements of spray characteristics, experimental investigations of atomizers, and application of atomizers. It demonstrates how to calculate and design atomizers and how to mea
• Adaptive protein evolution at the Adh locus in Drosophila. McDonald, John H.; Kreitman, Martin (1991). 351(6328) 652–654.

  PROTEINS often differ in amino-acid sequence across species. This difference has evolved by the accumulation of neutral mutations by random drift, the fixation of adaptive mutations by selection, or a mixture of the two. Here we propose a simple statistical test of the neutral protein evolution hypothesis based on a comparison of the number of amino-acid replacement substitutions to synonymous substitutions in the coding region of a locus. If the observed substitutions are neutral, the ratio of replacement to synonymous fixed differences between species should be the same as the ratio of replacement to synonymous polymorphisms within species. DNA sequence data on the Adh locus (encoding alcohol dehydrogenase, EC 1.1.1.1) in three species in the Drosophila melanogaster species subgroup do not fit this expectation; instead, there are more fixed replacement differences between species than expected. We suggest that these excess replacement substitutions result from adaptive fixation of selectively advantageous mutations.
• Liquid–Gas Systems. Fair, J. R.; Steinmeyer, D. E.; Penney, W. R.; Crocker, B. B. R. H. Perry, D. W. Green, J. O. Maloney (eds.) (1984). (Sixth )
• Si par une nuit d’hiver un voyageur : roman Calvino, Italo in Points (1981). (Vol. 81) Seuil, Paris.
• The age of a rare mutant gene in a large population. Maruyama, T (1974). 26(6) 669–673.

  The problems of estimating the time of extinction of a mutant allele and other re- lated quantities have been of considerable interest to population geneticists [1-4]. Nei and Li's work [2-4] are particularly relevant to human genetics, since they have estimated not only the number of individuals who will be affected in the future by presently known deleterious genes but also the time required for these genes to disappear from the population. It seems also interesting to ask a reverse question: Given that the present number of genes of a particular mutant allele occurring in a population is known, how long has the mutant persisted in the population? That is, what is the "age" of a mutant gene? This problem has been studied for selec- tively neutral genes by Kimura and Ohta [5] and Maruyama [6] independently. The topic of this note is to determine the average age of a rare mutant gene in large populations. There are many mutant genes, particularly deleterious ones, which appear to be very few in number and to be localized in a specific area of a human population. It is meaningless to assign them a gene frequency because such genes usually originate from a single mutant; they spread in a fairly restricted area and disappear in a few generations. Therefore the frequency varies depending upon the choice of reference population. For this type of situation, it is better to use a branching process model in which each gene reproduces independently of the other genes of the same mutant allele. This branching process model also assumes that there is no local density-dependent regulation of the population. Throughout this note, it is assumed that each mutant allele has unique origin and that there is no further mutation of the same type. An equivalent assumption is that the mutation rate multiplied by the number of the local population is much less than one. The mutant allele under consideration is denoted by A.
• The age of an allele in a finite population. Maruyama, T (1974). 23(2) 137–143.

  The age of an allele segregating in a finite population may be defined in two ways. They are (1) the age of a mutant gene that has never reached fixation in the population, and (2) the age including any fixation period in the past. Theoretical expressions for these are derived on the assumption that every mutant is unique.
• H. Corbin. L’homme de lumière dans le soufisme iranien. Jolivet, J. (1972). 182(2) 193–195.
• Origin and Differentiation of Human Races. Cavalli-Sforza, L. L. (1972). (1972) 15–25.

  EVOLUTION iS the transformation of species through time; but it is also the formation of differences among populations of the same species (or among species) that occupy differing environments. The two pheno- mena-differentiation in time and space-are naturally complementary aspects of the same process. Palaeont- ology has demonstrated that evolutionary trans- formations take place slowly; genetics has shown why this should be so. It is not at all surprising, therefore, that in human evolution long periods of time can elapse before substantial changes take place. Actually, some of the transformations characteristic of the evolution into Homo (such as the trebling in the capa- city of the hominid skull in a couple of million years) are among the fastest evolutionary changes observed. When we look at the variation between the human ethnic groups now living, we are amazed by the magnitude of such variation. In particular, skin colour inevitably impresses us very deeply, being a conspicuous, though in many respects superficial, difference. Other traits, mostly facial ones, are well- known aids in diagnosing the racial origin of an individual. Even a child learns soon to distinguish a white man from a black man or from an oriental. But when many more 'races' are distinguished, assign- ment of an individual to one of them on the basis of his external attributes is usually less successful. A test on this basis of the validity of taxonomies of human races has not been done. Probably, if one tried to allocate an individual, on the basis of his or her external appearance, to one of the thirty or so races which Garn (1961) distinguishes, for instance, the diagnosis would be in error relatively often. Most of the difficulties for taxonomy of human races arise from the fact that no matter how races are defined almost no measurable trait shows really sharp discontinuities from one 'race' to the next. On a map most traits-be they anthropometrics or gene frequencies-show gradual transitions or patterns of clinal variation. This suggests that during human evolution the extent of crossing must have been fairly large. Naturally, ethnic maps will show this clinal behaviour if in our analysis we concentrate on aboriginal populations and avoid those known or suspected major dis- placements over the last five hundred years or so. Otherwise we are confronted with extensive hetero- geneities. There are many communities of blacks and orientals and caucasians living side by side in many countries with very little, if any intermixture. Social barriers to interbreeding have in some cases survived over the short time elapsed since these migrations took place.