bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing biodiversity: historical ecology and biogeography of the Santa Catalina Island ground squirrel,
Otospermophilus beecheyi nesioticus
Authors: Rick Torben C. , Radde Hugh D. , Teeter Wendy G. , Elliott Smith Emma A. , Alvitre Cindi M. , Dagtas Nihan D. , Kennedy-Richardson Karimah O. , King Julie L. , Martinez Desireé R. , Schnorr Stephanie , Shirazi Sabrina , Maldonado Jesús E. , Hofman Courtney A.
Published: November 2024

People have influenced Earth’s biodiversity for millennia, including numerous introductions of domestic and wild species to islands. Here, we explore the origins and ecology of the Santa Catalina Island ground squirrel (SCIGS;
Otospermophilus beecheyi nesioticus
), one of only five endemic terrestrial mammals found on California’s Santa Catalina Island. We synthesized all records of archaeological/palaeontological SCIGS, conducted radiocarbon dating and stable isotope analysis of the potentially earliest SCIGS remains and performed genetic analysis of modern SCIGS. Squirrels were not identified in island palaeontological deposits, but at least 12 island archaeological sites contain SCIGS bones, including some that are butchered or burned. All directly dated SCIGS bones are Late Holocene in age and younger than approximately 1290 cal BP. The first mitochondrial genome for modern
Otospermophilus beecheyi
and 15 modern SCIGS mitogenomes document at least one introduction of squirrels. Stable isotope data indicate variable SCIGS diets and potential subsidies from marine environments to terrestrial plants consumed by some individuals. We cannot rule out a natural overwater dispersal, but the earliest SCIGS remains post-date the earliest evidence for people by several millennia and, along with other lines of evidence, support a human-assisted translocation of squirrels during the Late Holocene. These data illustrate the important role of Indigenous people in shaping and enhancing island biodiversity and ecology around the world.
The role of human hunters and natural predators in shaping the selection of behavioural types in male wild turkeys
Authors: Gulotta Nick A. , Wightman Patrick H. , Collier Bret A. , Chamberlain Michael J.
Published: November 2024

The expression of behaviour can vary both among (i.e. behavioural types (BTs)) and within individuals (i.e. plasticity), and investigating causes and consequences of variation has garnered significant attention. Conversely, studies quantifying harvest-induced selection (HIS) on behavioural traits have received significantly less attention, and work investigating HIS and natural selection simultaneously is rare. We studied sources of variation in three movement traits that represented risk-taking and one trait that represented exploration in male eastern wild turkeys (
Meleagris gallopavo silvestris
). We used data from 109 males in two hunted populations located in Georgia and South Carolina, USA. We assessed how both hunters and natural predators simultaneously influenced the selection of male turkey BTs. We found significant among-individual variation in all movement traits and adjustments in risk-taking and exploration relative to whether hunting was occurring. We observed that predators selected against similar BTs across both populations, whereas hunters selected for different BTs across populations. We also demonstrated that significant HIS acts on risk-taking behaviours in both populations, which could render wild turkeys more difficult to harvest if these traits are indeed heritable.
The roles of habitat isolation, landscape connectivity and host community in tick-borne pathogen ecology
Authors: Shaw Grace , Lilly Marie , Mai Vincent , Clark Jacoby , Summers Shannon , Slater Kimetha , Karpathy Sandor , Nakano Angie , Crews Arielle , Lawrence Alexandra , Salomon Jordan , Sambado Samantha Brianne , Swei Andrea
Published: November 2024

Habitat loss and forest fragmentation are often linked to increased pathogen transmission, but the extent to which habitat isolation and landscape connectivity affect disease dynamics through movement of disease vectors and reservoir hosts has not been well examined. Tick-borne diseases are the most prevalent vector-borne diseases in the United States and on the West Coast,
Ixodes pacificus
is one of the most epidemiologically important vectors. We investigated the impacts of habitat fragmentation on pathogens transmitted by
I. pacificus
and sought to disentangle the effects of wildlife communities and landscape metrics predictive of pathogen diversity, prevalence and distribution. We collected pathogen data for four co-occurring bacteria transmitted by
I. pacificus
and measured wildlife parameters. We also used spatial data and cost-distance analysis integrating expert opinions to assess landscape metrics of habitat fragmentation. We found that landscape metrics were significant predictors of tick density and pathogen prevalence. However, wildlife variables were essential when predicting the prevalence and distribution of pathogens reliant on wildlife reservoir hosts for maintenance. We found that landscape structure was an informative predictor of tick-borne pathogen richness in an urban matrix. Our work highlights the implications of large-scale land management on human disease risk.
Space as a mental toolbox in the representation of meaning
Authors: Zarzeczna Natalia , Bertlich Tisa , Rutjens Bastiaan T. , Gerstner Ida , von Hecker Ulrich
Published: November 2024

The experience of meaning has been found to be mapped onto spatial proximity whereby coherent—in contrast to incoherent—elements in a set are mentally represented as closer together in physical space. In a series of four experiments, we show that spatial representation of coherence is malleable and can employ other meaningful concrete dimensions of space that are made salient. When given task instructions cueing verticality, participants represented coherence in the upper vertical location when making judgements about the logical validity of realistic (Experiments 1 and 4) and unrealistic syllogistic scenarios (Experiment 3). When the task instruction made the spatial proximity between the stimuli materials and the participant salient (subjective proximity), participants represented coherence as spatially close to themselves (Experiment 2). We also found that being accurate in judging the validity of syllogisms was associated with representing coherence in the upper visual field or close to oneself. Overall, our findings show that identifying semantic links between an abstract concept and a given spatial dimension involves using that dimension to create spatial metaphoric mappings of the concept.
Heliconius
butterflies use wide-field landscape features, but not individual local landmarks, during spatial learning
Authors: Moura P. A. , Cardoso M. Z. , Montgomery S. H.
Published: November 2024

Spatial learning is vital in foraging ecology. Many hymenopteran insects are adept spatial foragers that rely on visual cues contained within broader wide-field scenes for central place foraging from a central nest. By contrast, for butterflies, which lack central nest sites, visual cue use during spatial foraging is less understood.
Heliconius
butterflies, however, exhibit stable nocturnal roosts, strong site fidelity and a sophisticated capacity for spatial navigation. This study furthers our understanding of
Heliconius
spatial learning by testing whether
H. erato
can associate a spatially informative visual cue with artificial feeders. We explored the relative importance of a visual local landmark compared with broader, wide-field visual cues, through experiments with (i) a fixed rewarded feeder with a local landmark; (ii) a mobile rewarded feeder with the landmark as the sole reliable cue; (iii) the same setup while blocking visual access to external landscape features. Our data suggest that
Heliconius
butterflies learn static feeder locations without relying on a local individual landmark. Instead, we suggest they integrate broader landscape and celestial cues. This suggests that
Heliconius
butterflies and central place foraging hymenopterans likely share similar visual navigation strategies, using wide-field, low-resolution views rather than focusing on specific individual landmarks.
Bifurcation analysis of pressure-induced detachment of a rod adhered to a plate
Authors: Turzi S. S. , Ambrosi D. , Zoppello M.
Published: November 2024

We study the lift of an elastica adhering to a flat rigid surface induced by a pressure difference. Adhesion is modelled by a cohesive force that decreases linearly with separation. Using a nonlinear local analysis, we determine the bifurcation diagram that governs the peeling process under quasi-static conditions. We show that the delamination emerges through a discontinuous transition: a normal form of the bifurcation diagram allows us to draw in a simple way the main physical mechanism, elucidating the local validity of the theory at the transition. We predict that the pressure, as a function of the detachment length, undergoes an initial drop followed by an approximately constant behaviour, while the detachment length at the transition is always finite and is roughly proportional to the elasto-adhesion length. This analysis can be the starting point to understand more complex-related problems that arise in fracture mechanics or in biology, such as testing of adhesives in a flowfield and the arterial dissection.
Detecting damage in composites using volume decomposition analysis of tomographic data
Authors: Middleton Ceri A. , Amjad Khurram , Christian William J. R. , Hilmas Ashley M. , Przybyla Craig , Patterson Eann A.
Published: November 2024

Detection of damage in a single tow ceramic matrix composite specimen has been achieved using orthogonal decomposition of volumetric tomographic datasets collected at four tensile loads. This decomposition approach has been applied at two different length scales: (i) individual fibres and (ii) bulk volumes containing fibres and matrix material. Volumes were first decomposed to feature vectors, orders of magnitude smaller than the original volume they describe, and then comparisons between datasets at different load levels were made in feature vector space. The results show quantitative measurements of damage location, damage morphology and the relative growth of this damage with increased load when compared with a dataset with less or no damage. No prior knowledge of the dataset or training of algorithms is required for damage to be detected, it is only necessary that at least two datasets are available for comparison, e.g. from
in situ
or repeated scanning measurements. Results are generated on significantly shorter timescales when compared with previous automated approaches to tomography data processing. This approach has the potential to be applied to damage detection in a range of materials through comparisons of volumetric datasets from a range of measurement or computational techniques.
Inbreeding avoidance and cost in a small, isolated trout population
Authors: Bell Donovan A. , Kovach Ryan P. , Whiteley Andrew R.
Published: November 2024

The persistence of small populations is influenced by the degree and cost of inbreeding, with the degree of inbreeding depending on whether close-kin mating is passively or actively avoided. Few studies have simultaneously studied these factors. We examined inbreeding in a small, isolated population of westslope cutthroat trout using extensive genetic and demographic data. Passive inbreeding avoidance was low, with predicted lifetime dispersal of approximately 36 and 74 m for females and males, respectively. Additionally, we found limited evidence for active inbreeding avoidance during reproduction. Relatives remained spatially clustered into adulthood, and observed relatedness among mate pairs was greater than expected under random mating by 0.09, suggesting that inbreeding is a concern in this population. Further, we examined sex-specific inbreeding depression throughout the life cycle and provide evidence for inbreeding depression in some fitness components, including family size, juvenile survival and reproductive success. Our results suggest that, in an at-risk trout population, limited passive and active inbreeding avoidance lead to a higher degree of inbreeding than expected under random mating. Observed inbreeding, along with evidence for fitness reduction due to inbreeding depression, could put the population at a heightened risk of decline or extirpation.
Microbiome transfer from native to invasive species may increase invasion risk
Authors: Martignoni Maria M. , Kolodny Oren
Published: November 2024

In a fast-changing world, understanding how organisms adapt to their environment is a pressing necessity. Research has focused on genetic adaptation, while our understanding of non-genetic modes is still in its infancy. The host-associated microbiome can be considered a non-genetic mode of adaptation, which can strongly influence an organism’s ability to cope with its environment. However, the role of the microbiome in host ecological dynamics is largely unexplored, particularly in animal communities. Here, we discuss the following hypothesis: invasive species may rapidly adapt to local conditions by adopting beneficial microbes from similar co-occurring native species. This occurs when the invader’s fitness is influenced by adaptation to local conditions that is facilitated by microbes acquired from native microbiomes. We present a minimal mathematical model to explore this hypothesis and show that a delayed acquisition of native microbes may explain the occurrence of an invasion lag. Overall, our results contribute to broadening the conceptualization of rapid adaptation via microbiome transfer and offer insights towards designing early intervention strategies for invasive species management.
Sharing sleeping sites disrupts sleep but catalyses social tolerance and coordination between groups
Authors: Loftus J. Carter , Harel Roi , Ashbury Alison M. , Núñez Chase L. , Omondi George P. , Muttinda Mathew , Matsumoto-Oda Akiko , Isbell Lynne A. , Crofoot Margaret C.
Published: November 2024

Sleeping refuges—like other important, scarce and shareable resources—can serve as hotspots for animal interaction, shaping patterns of attraction and avoidance. Where sleeping sites are shared, individuals balance the opportunity for interaction with new social partners against their need for sleep. By expanding the network of connections within animal populations, such night-time social interactions may have important, yet largely unexplored, impacts on critical behavioural and ecological processes. Here, using GPS and tri-axial accelerometry to track the movements and sleeping patterns of wild olive baboon groups (
Papio anubis
), we show that sharing sleeping sites disrupts sleep but appears to catalyse social tolerance and coordinated movement between groups. Individual baboons experienced shorter and more fragmented sleep when groups shared a sleeping site. After sharing sleeping sites, however, otherwise independent groups showed a strong pattern of spatial attraction, moving cohesively for up to 3 days. Our findings highlight the influence of night-time social interactions on daytime social relationships and demonstrate how a population’s reliance on, and need to share, limiting resources can drive the emergence of intergroup tolerance.
Greater plasticity in CTmax with increased climate variability among populations of tailed frogs
Authors: Cicchino Amanda S. , Ghalambor Cameron K. , Forester Brenna R. , Dunham Jason D. , Funk W. Chris
Published: November 2024

Temporally variable climates are expected to drive the evolution of thermal physiological traits that enable performance across a wider range of temperatures (i.e. climate variability hypothesis, CVH). Spatial thermal variability, however, may mediate this relationship by providing ectotherms with the opportunity to behaviourally select preferred temperatures (i.e. the Bogert effect). These antagonistic forces on thermal physiological traits may explain the mixed support for the CVH within species despite strong support among species at larger geographical scales. Here, we test the CVH as it relates to plasticity in physiological upper thermal limits (critical thermal maximum—CTmax) among populations of coastal tailed frogs (
Ascaphus truei
). We targeted populations that inhabit spatially homogeneous environments, reducing the potentially confounding effects of behavioural thermoregulation. We found that populations experiencing greater temporal thermal variability exhibited greater plasticity in CTmax, supporting the CVH. Interestingly, we identified only one site with spatial temperature variability and tadpoles from this site demonstrated greater plasticity than expected, suggesting the opportunity for behavioural thermoregulation can reduce support for the CVH. Overall, our results demonstrate one role of climate variability in shaping thermal plasticity among populations and provide a baseline understanding of the impact of the CVH in spatially homogeneous thermal landscapes.
Identifying signatures of the earliest benthic bulldozers in emergent subaerial conditions during the colonization of land by animals
Authors: Wang Zekun , Davies Neil S. , Liu Alexander G. , Minter Nicholas J. , Rahman Imran A.
Published: November 2024

The colonization of land by animals was a milestone in the history of life. Approximately 100 million years before full terrestrialization, early animals sporadically traversed emergent subaerial substrates, leaving behind trace fossils recording their activities. However, identifying temporarily emergent environments and determining the affinities, motility and subaerial endurance of the trace-makers, and the timing and magnitude of their impacts on marginal-marine environments, are challenging. Here, we used semi-resolved computational fluid dynamics–discrete element method coupling to simulate trace formation on non-cohesive sediments in submerged and emergent subaerial conditions. This revealed instability-induced morphological signatures that allow us to identify the earliest terrestrial trace fossils. Quantitative metrics enable us to infer that the putative earliest terrestrial trace-makers were molluscs, and dimensional analysis suggests that their subaerial excursions could last at least 15 min. These organisms navigated emergent environments from the early Cambrian (stage 2), tens of millions of years earlier than arthropods. This quantitative paradigm provides new insights into the palaeobiology of the earliest subaerial bulldozers and highlights that mollusc-like animals were among the first ecosystem engineers to enter marginal-marine settings. They may thus have contributed to the establishment of marginal-marine biogeochemical cycles, laying the groundwork for subsequent terrestrialization by other animals.
Cooling down is as important as warming up for a large-bodied tropical reptile
Authors: Barham Kaitlin E. , Dwyer Ross G. , Frere Celine H. , Bentley Lily K. , Baker Cameron J. , Campbell Hamish A. , Irwin Terri R. , Franklin Craig E.
Published: November 2024

An ectotherm’s performance and physiological function are strongly tied to environmental temperature, and many ectotherms thermoregulate behaviourally to reach optimum body temperatures. Tropical ectotherms are already living in environments matching their thermal tolerance range and may be expected to conform to environmental temperatures. We tracked the body temperatures (
T
b
) of 163 estuarine crocodiles across 13 years and compared
T
b
of 39 crocodiles to water temperature gathered using fish-borne sensors (
T
w
) across 3 years (2015–2018). While
T
b
largely conformed closely to
T
w
, we found inter- and intra-individual differences in relative body temperature (
T
b
–
T
w
) that depended on sex and body size as well as the time of day and year. Deviations from
T
w
, especially during the warm parts of the year, suggest that thermoregulatory behaviour was taking place: we found patterns of warming and cooling events that seemed to mediate this variation in
T
b
. Thermoregulatory behaviour was observed most frequently in larger individuals, with warming events common during winter and cooling events common during summer. By observing free-ranging animals across multiple years, we found that estuarine crocodiles show yearly patterns of active cooling and warming behaviours that modify their body temperature, highlighting their resilience in the face of recent climate warming. Our work also provides the first evidence for thermal type in large-bodied reptiles.
Preliminary evidence that Bunyamwera virus causes severe disease characterized by systemic vascular and multiorgan necrosis in an immunocompromised mouse model
Authors: Dutuze M. Fausta , Clark Samantha D. , Del Piero Fabio , Christofferson Rebecca C.
Published: November 2024

Bunyamwera virus (BUNV) is the prototypical member of the Bunyamwera serogroup within the Orthobunyvirus genus. BUNV is transmitted by mosquito vectors of the genera Culex, Aedes and Anopheles and has historically circulated in East Africa, though the transmission has been observed in Argentina. BUNV has been identified as an agent of human and animal disease and has also been misdiagnosed as other agents. BUNV is often thought to be an agent of mild febrile illness in humans, though it can cause abortions in ruminants and neurological disease in horses. Joint pain and gastritis have also been attributed to BUNV. There are limited data concerning the possible spectrum of disease and extent of pathogenesis of BUNV infection, and there are currently no therapeutics or vaccines available. Furthermore, options for animal models for Orthobunyaviruses in general – of which BUNV is the prototypical member – are limited. Eight mice deficient in the type I interferon response were infected with BUNV, and all developed overt disease. All mice developed detectable viraemia and clinical signs, including weight loss, hunched posture and lethargy. Three of the eight mice developed severe diseases, including vascular necrosis and necrosis in the liver, lungs, reproductive organs, bone marrow and spleen, as well as haemorrhages (n=1) and severe diffuse facial oedema (n=3), reminiscent of the pathology of Schmallenberg and the Arenaviruses Lassa and Lujo viruses. Thus, BUNV infection of IRF3/7 DKO mice could serve as a BSL-2 model for severe diseases of higher-risk group viruses, which often must be studied at BSL-4. Additionally, our results suggest that BUNV may have the ability to cause severe disease in immunocompromised hosts. Thus, further investigation into the potential spectrum of pathogenesis due to BUNV is important to prioritize for outbreak response, diagnostics and the development of countermeasures.
Multi-context seeds enable fast and high-accuracy read mapping
Authors: Tolstoganov Ivan , Martin Marcel , Sahlin Kristoffer
Published: November 2024

A key step in sequence similarity search is to identify seeds that are found in both the query and the reference sequence. A seed is a shorter substring (e.g., ak-mer) or pattern (e.g., a spacedk-mer) constructed from the sequences. A well-known trade-off in applications such as read mapping is that longer seeds offer fast searches through fewer spurious matches but lower sensitivity in variable regions as longer seeds are more likely to harbor mutations. Some recent developments on seed constructs have considered approximate (or fuzzy) seeds such ask-min-mers, strobemers, BLEND, SubSeqHash, TensorSketch, and more, that can match over smaller mutations and, thus, suffer less from sensitivity issues in variable regions. Nevertheless, the sensitivity-to-speed trade-off still exists for such constructs. In other applications, such as genome assembly, using multiple sizes ofk-mers is effective. While this can be achieved in read mapping through, e.g., MEM construction from an FM-index, such seed constructs are typically much slower than hash-based constructs.

To this end, we introduce multi-context seeds (MCS). In brief, MCS are strobemers where the hashes of individual strobes are partitioned in the hash value representing the seed. Such partitioning enables a cache-friendly approach to search for both full and partial matches of a subset of strobes. For example, both the full strobemer and the first strobe (ak-mer) can be queried. We demonstrate that MCS improves sequence matching statistics over standard strobemers andk-mers without compromising seed uniqueness. We demonstrate the practical applicability of MCS by implementing them in strobealign. Strobealign with MCS comes at no cost in memory and only little cost in runtime while offering increased mapping accuracy over default strobealign using simulated Illumina reads across genomes of various complexity. We also show that strobealign with MCS outperforms minimap2 in short-read mapping and is comparable to BWA-MEM in accuracy in high-variability sequences. MCS provides a fast seed alternative that addresses the trade-offs between seed length and alignment accuracy.
A unique malignant cell type per patient tumor is encoded in each cancer cell transcriptome.
Authors: Saurty-Seerunghen Mirca S , El-Habr Elias A , Eliaz Yossi , Bellenger Lea , Antoniewski Christophe , Chneiweiss Herve , Junier Marie-Pierre
Published: November 2024

Deciphering shared features between patients through unsupervised analyses of tumor single-cell transcriptomes is hindered by the predominant clustering of malignant cells based on the patient's tumor of origin. In contrast, cancer-associated non-malignant cells within tumors cluster according to their somatic cell type (e.g. macrophage, fibroblast, astrocyte), regardless of the individual patient. We investigated the origin of this contrasting clustering behavior using computational analyses and novel data sampling techniques across 160 tumors representing 9 distinct cancer types. This led to the unexpected disclosing of tumor-specific malignant cell types. We demonstrate that tumor-driven malignant cell clustering is independent from technical or computational biases, nor is it reducible to defined gene sets with tumor-specific expression across all examined cancers. On the opposite, we unveil redundant information dispersed across the transcriptome that encodes a unique identity shared by the malignant cells within each tumor. Additionally, we found a similar genomic encoding for the identity of normal cell types. Finally, we demonstrate that malignant cell identities are maintained across space and over time, as are the identities of normal somatic cells types. These findings suggest the establishment of a distinct type of malignant cells within each tumor, robustly and diffusively encoded across the entire transcribed genome.
COMPARISON OF UNIVARIATE AND MULTIVARIATE REFERENCE INTERVAL METHODS
Authors: Mergen Esra Kutsal , Karahan Sevilay
Published: November 2024

Background

In clinical practice, reference intervals play a pivotal role in interpreting laboratory test results. Yet, when several tests are taken into consideration simultaneously, the traditional univariate intervals might not suffice due to the elevated risk of Type 1 errors.

Methods

This study introduces and evaluates two multivariate reference interval techniques: one based on Mahalanobis distance and the other an adaptation of the multivariate confidence interval. Using Monte Carlo simulations, we focused our assessments on the interplay between “Serum Ferritin and Transferrin Saturation” values.

Results

Upon evaluation, it became evident that the multivariate methods significantly reduced false positives. They presented enhanced accuracy over traditional univariate intervals. Notably, the method involving Mahalanobis distance stood out in terms of efficacy.

Contributions

Beyond presenting novel techniques, our research underscores the importance and potential of using multivariate approaches in clinical lab settings. The findings can guide better medical decision-making, ensuring optimized allocation of healthcare resources.

Highlights

We present two alternative multivariate reference interval methods that consider the relationship between two analytes simultaneously.

Through comprehensive simulation studies, we compare the proposed methods with the conventional univariate reference interval method.

Our results show the superior performance of our proposed methods in terms of patient rate, sensitivity, specificity, and overall accuracy.

We discuss the practical relevance of these new methods.
Enhancing Ischemic Stroke Management: Leveraging Machine Learning Models for Predicting Patient Recovery After Alteplase Treatment
Authors: Khorsand Babak , Vaghf Atena , Salimi Vahide , Zand Maryam , Ghoreishi Seyed Abdolreza
Published: November 2024

Aim

Ischemic stroke remains a leading global cause of morbidity and mortality, emphasizing the need for timely treatment strategies. This study aimed to develop a machine learning model to predict clinical outcomes in ischemic stroke patients undergoing Alteplase therapy, thereby supporting more personalized care.

Methods

Data from 457 ischemic stroke patients were analyzed, including 50 demographic, clinical, laboratory, and imaging variables. Five machine learning algorithms—k-nearest neighbors (KNN), support vector machines (SVM), Naïve Bayes (NB), decision trees (DT), and random forest (RF)—were evaluated for predictive accuracy. The primary evaluation metrics were sensitivity and F-measure, with an additional feature importance analysis to identify high-impact predictors.

Results

The Random Forest model showed the highest predictive reliability, outperforming other algorithms in sensitivity and F-measure. Furthermore, by using only the top-ranked features identified from the feature importance analysis, the model maintained comparable performance, suggesting a streamlined yet effective predictive approach.

Conclusion

Our findings highlight the potential of machine learning in optimizing ischemic stroke treatment outcomes. Random Forest, in particular, proved effective as a decision-support tool, offering clinicians valuable insights for more tailored treatment approaches. This model’s use in clinical settings could significantly enhance patient outcomes by informing better treatment decisions.
Neural coding of choice and outcome are modulated by uncertainty in orbitofrontal but not secondary motor cortex
Authors: Romero-Sosa Juan Luis , Yeghikian Alex , Wikenheiser Andrew M. , Blair Hugh T. , Izquierdo Alicia
Published: November 2024

Orbitofrontal cortex (OFC) and secondary motor cortex (M2) are both implicated in flexible reward learning but the conditions that differentially recruit these regions are not fully understood. We imaged calcium activity from single neurons in OFC or M2 duringde novolearning of uncertain reward probability schedules. Predictions of choice were decoded from M2 neurons with high accuracy under all certainty conditions, but were more accurately decoded from OFC neurons under greater uncertainty. In M2, the proportion of outcome-selective neurons decreased with uncertainty whereas this proportion remained stable in OFC, due to an increased recruitment of reward-selective neurons across levels of uncertainty. Decoding accuracy of both choice and outcome were predicted by indices of flexible strategy like Win-Stay and Lose-Shift in OFC, but not M2. When schedules were experienced in increasing and then decreasing uncertainty, chemogenetic perturbation of M2 and OFC neurons resulted in opposing roles in certain and uncertain conditions, respectively. Our results indicate that M2 neurons are causally involved in learning of more certain conditions, whereas OFC neurons preferentially encode choices and outcomes that foster greater reliance on adaptive strategies under conditions of uncertainty. This reveals a novel functional heterogeneity within frontal cortex in support of flexible learning.
Classifying the molecular functions of transcription factors beyond activation and repression
Authors: Dong Jinhong , Guertin Michael J.
Published: November 2024

Notch signaling is a highly conserved pathway activated by dynamic cellular interactions that initiates a molecular cascade that ultimately drives changes in gene expression. The Notch transcriptional complex (NTC) regulates genes that influence development and homeostasis. In this issue ofGenes & Development, Rogers and colleagues (doi:10.1101/gad.352108.124) leverage a rapid Notch activation system combined with molecular genomic profiling to reveal that the NTC regulates the release of paused RNA polymerase to activate direct target genes. They also highlight the role of the SWI/SNF chromatin remodeling complex in establishing and maintaining chromatin accessibility to potentiate the activation of NTC target genes.
Buckling by disordered growth
Authors: Ramachandran Rahul G. , Alert Ricard , Haas Pierre A.
Published: November 2024

Buckling instabilities driven by tissue growth underpin key developmental events such as the folding of the brain. Tissue growth is disordered due to cell-to-cell variability, but the effects of this variability on buckling are unknown. Here, we analyze what is perhaps the simplest setup of this problem: the buckling of an elastic rod with fixed ends driven by spatially varying, yet highly symmetric growth. Combining analytical calculations for simple growth fields and numerical sampling of random growth fields, we show that variability can increase as well as decrease the growth threshold for buckling, even when growth variability does not cause any residual stresses. For random growth, we find numerically that the shift of the buckling threshold correlates with spatial moments of the growth field. Our results imply that biological systems can either trigger or avoid buckling by exploiting the spatial arrangement of growth variability.

Published by the American Physical Society
2024
Concept image framework for derivatives from contour graphs
Authors: Emigh Paul J. , Manogue Corinne A.
Published: November 2024

Physics experts and students commonly use a variety of representations when working with partial derivatives, including symbols, graphs, and words. One especially powerful representation is the contour graph. In open-ended problem-solving interviews with nine upper-division physics students, we asked students to determine derivatives from contour graphs with electrostatic and thermodynamic contexts. Students undertook three overarching actions: (i) orienting to the given graph, (ii) finding one or more derivatives, and (iii) reflecting on the task. In general, students tended to have more difficulty with the thermodynamic task than the electrostatic one. Students made use of a variety of representational features throughout the interviews, namely by annotating the provided contour graphs in ways that highlighted what is held constant. We use these results to generalize the existing concept image framework for ordinary derivatives to create a framework useful for understanding student ideas about multivariable derivatives. In particular, we add a new layer to the framework—the layer—that calls attention to how students do or do not attend to which variables are changing (or remaining constant) when finding a derivative. We view the change layer as a powerful central idea for both further research and the development of instructional tasks for physics students.

Published by the American Physical Society
2024
Stacking of charge-density waves in
2H−NbSe2
bilayers
Authors: Cossu F. , Nafday D. , Palotás K. , Biderang M. , Kim H.-S. , Akbari A. , Di Marco I.
Published: November 2024

We employ electronic-structure calculations to investigate the charge-density waves and periodic lattice distortions in bilayer 2H−NbSe2. We demonstrate that the vertical stacking can give rise to a variety of patterns that may lower the symmetry of the charge-density waves exhibited separately by the two composing 1H−NbSe2 monolayers. The general tendency to a spontaneous symmetry breaking observed in the ground state and the first excited states is shown to originate from a non-negligible interlayer coupling. Simulated images for scanning tunneling microscopy as well as geometric structure factors show signatures of the different stacking orders. This may not only be useful to reinterpret past experiments on surfaces and thin films, but it may also be exploited to devise ad hoc experiments for the investigation of the stacking order in 2H−NbSe2. We anticipate that our analysis not only applies to the 2H−NbSe2, but is also relevant for thin films and bulk, whose smallest centrosymmetric component is indeed the bilayer. Finally, our results illustrate clearly that the vertical stacking is not only important for 1T structures, as exemplified by the metal-to-insulator transition observed in 1T−TaS2, but seems to be a general feature of metallic layered transition metal dichalcogenides as well.

Published by the American Physical Society
2024
Anomalous Long-Ranged Influence of an Inclusion in Momentum-Conserving Active Fluids
Authors: Arnoulx de Pirey Thibaut , Kafri Yariv , Ramaswamy Sriram
Published: November 2024

We show that an inclusion placed inside a dilute Stokesian suspension of microswimmers induces power-law number-density modulations and flows. These take a different form depending on whether the inclusion is held fixed by an external force—for example, an optical tweezer—or if it is free. When the inclusion is held in place, the far-field fluid flow is a Stokeslet, while the microswimmer density decays as 1/r2+ε, with r the distance from the inclusion and ε an anomalous exponent which depends on the symmetry of the inclusion and varies continuously as a function of a dimensionless number characterizing the relative amplitudes of the convective and diffusive effects. The angular dependence takes a nontrivial form which depends on the same dimensionless number. When the inclusion is free to move, the far-field fluid flow is a stresslet, and the microswimmer density decays as 1/r2 with a simple angular dependence. These long-range modulations mediate long-range interactions between inclusions that we characterize.

Published by the American Physical Society
2024
Lifted TASEP: A Solvable Paradigm for Speeding up Many-Particle Markov Chains
Authors: Essler Fabian H. L. , Krauth Werner
Published: November 2024

Virtually all Markov-chain Monte Carlo algorithms used for sampling a given distribution are reversible, and they satisfy the detailed-balance condition. For local chains, this leads to a slow, diffusive exploration of sample space. Significant speedups can be achieved through nonreversible algorithms with the given distribution as a targeted steady state. However, nonreversible algorithms for sampling are difficult to set up and to analyze, and exact speedup results for interacting many-particle systems are very rare. Here, we introduce the “lifted” totally asymmetric simple exclusion process (TASEP) as an exactly solvable paradigm for nonreversible many-particle Markov chains. It samples the same hard-sphere distribution as the Metropolis algorithm for symmetrically diffusing hard-core particles on a one-dimensional lattice. We solve the lifted TASEP by an unusual kind of coordinate Bethe ansatz and show that it exhibits polynomial (in particle number) speedups in the relaxation time for the asymptotic approach of the steady state, as well as the nonasymptotic mixing time, compared to both Metropolis and Kardar-Parisi-Zhang-based dynamics. The lifted TASEP is the reduction onto the one-dimensional lattice of the successful hard-sphere event-chain Monte Carlo algorithm, and we discuss that it can likewise be generalized to soft interaction potentials.

Published by the American Physical Society
2024
2,4-Dichloro-6-{N-[2-(trifluoromethyl)phenyl]carboximidoyl}phenol
Authors: Xantini Zizipho , Muller Alfred , Lammertsma Koop
Published: November 2024

The title compound, C14H8Cl2F3NO, was synthesized by the condensation between trifluoromethylaniline and dichlorosalicylaldehyde by nucleophilic addition, forming a hemiaminal, followed by a dehydration to generate an imine. The compound crystallizes in an orthorhombic Pbca (Z = 8) space group with a dihedral angle of 44.70 (5)° between the two aromatic rings. In the crystal, the molecules pack together to form a zigzag pattern along the c axis.
Self-created or collaborative? The effects of virtual influencers' identity type and post type on purchase intentions
Authors: Jiang Kan , Zhou Dailan , Bao Xiaoning , Mo Silan
Published: November 2024

Purpose

Considering that when endorsing the same product, virtual influencers with different identity types (self-created, collaborative) can have different impacts on consumers' purchasing behaviors, this paper aims to explore how to maximize the impact effects of the VIs' respective identities. It provides companies with new perspectives on endorsement strategies.

Design/methodology/approach

The interaction between VI identity type and post type (informational, storytelling) on purchase intention was analyzed in four experiments (N = 1,007), considering informational and normative social influence as intermediate mechanisms and consumer self-construal as moderators.

Findings

The findings show that self-created VI is suited to informational posts and collaborative VI to storytelling posts. This identity-content match effectively triggers the social influence mechanism: informational posts of self-created VI significantly enhance informational social influence. In contrast, storytelling posts of collaborative VI primarily stimulate normative social influence. Consumer self-construal also moderates the process of influencing mechanisms.

Originality/value

Based on social influence theory and matching theory, this paper confirms the existence of an interaction between VI identity types, which influences consumers' purchase intention through informational and normative social influence. This finding fills the research gap in the field of VI endorsement strategy. It also emphasizes the importance of consumer self-construal and contributes new insights into the related field.
Living one’s calling independently: the role of online labor platforms for different dynamics of calling enactment
Authors: Affolter Lorenz , Straub Caroline , Spurk Daniel
Published: November 2024

Purpose

This study investigates the diverse career experiences of gig workers by looking at a sample of gig workers that are living a calling through online labor platforms (OLPs). Drawing from the systems informed positive psychology (SIPP) framework we examine the experiences and dynamics through which individuals can enact their calling through OLPs.

Design/methodology/approach

We conducted 34 semi-structured interviews with gig workers who are able to live their calling through OLPs. The interviews were analyzed by using a grounded theory approach.

Findings

Our findings reveal that gig workers sense of living a calling is rooted in the experience of being and feeling independent. Furthermore, we identify three dynamics of calling enactment through OLPs which are: (1) engaging in personal development, (2) constructing social fit and (3) stabilizing finances.

Originality/value

While many studies document the precarious nature of the gig economy, our paper offers rich insight into positive career experiences of gig workers. Through taking a systemic view on individuals’ ability to live a calling, we illustrate how individuals interact with different features of OLPs to enact their calling. Finally, we suggest that besides direct dynamics of calling enactment there are also indirect dynamics of calling enactment that play an important role in individuals’ ability to live a calling in the gig economy.
Investigating the mediating role of national governance bundles and institutional ownership on the relationship between risk governance disclosure and market valuation: evidence from Sub-Saharan Africa
Authors: Areneke Geofry , Tunyi Abongeh A. , Nakpodia Franklin
Published: November 2024

Purpose

The paper aims to comparatively examine the impact of risk governance disclosure (RGD) on the market valuation of firms in Sub-Saharan Africa (SSA) and the mediating role of institutional investment and national governance bundles (NGB).

Design/methodology/approach

Using a dynamic system generalized method of moments estimation to control for endogeneity, the data for this research is manually collected from the annual reports of small and large firms in Nigeria (80 firms) and South Africa (100 firms) for the period 2012–2017 (900 firm years).

Findings

The authors find that firm RGD directly impacts firm valuation positively, but this association is significantly mediated by national governance practices (bundles) and institutional investment. The authors also develop a conceptual framework that shows the direct and indirect impact of RGD on firm market valuation.

Originality/value

The paper contributes to the comparative corporate governance literature in three ways. First, the authors show that differences in country-level RGD are explained by the maturation of governance regulations and institutions in each country. Second, despite the differences in the level of maturity of governance institutions across countries, stock markets value risk governance information. Finally, the study develops a conceptual framework that addresses prior inconsistent findings by showing that firm-level NGB and institutional investment significantly mediate the association between RGD and market valuation.
The relation between perceived autonomy support and (in) formal learning when using a PDP: the mediating role of self-direction in learning
Authors: van der Baan Niels , Lejeune Christophe , Beausaert Simon , Raemdonck Isabel
Published: November 2024

Purpose

To keep up with their changing environment, organizations are investing in continuous skills development of their employees and therefore implement personal development plans (PDPs). However, to be effective, PDPs require employees to show self-direction in learning (SDL). Autonomy-supportive supervisors can foster employees’ SDL. Therefore, the purpose of this cross-sectional study is two-fold. First, this study explores the relationship between perceived autonomy support and learning at the workplace. Second, this study investigates the mediating role of SDL when using a PDP.

Design/methodology/approach

Based on data from a convenience sample from employees in various industries (n = 193), structural equation modelling was used to investigate the relationships between the different variables.

Findings

First, a positive relationship was found between perceived autonomy support and informal learning activities, but not with formal learning activities. Second, results indicated that SDL when using a PDP mediates the relation between perceived autonomy support and both formal and informal learning activities at the workplace. These results suggest that a supervisor who is perceived as autonomy supportive can foster employees’ SDL when using a PDP and, in turn, support learning at the workplace.

Practical implications

Also, these findings indicate that autonomy-supportive supervisors can encourage the undertaking of learning activities by stimulating SDL when using a PDP.

Originality/value

For a PDP to be effective, a degree of SDL is assumed. To the best of the authors’ knowledge, this is the first study to investigate SDL within a PDP setting.