Hasil untuk "Physical anthropology. Somatology"

Yoichi Tanaka, Nao Uchima, Wakana Ebisu et al.

Abstract Background This study examines whether acute psychosocial stress induced by the Trier Social Stress Test (TSST) alters pressure pain threshold (PPT) in healthy university students. Furthermore, we investigated how overall social skills and its subscales relate to stress-induced changes in PPT and whether trait anxiety moderates these relationships. Methods A total of 34 healthy university students (14 males, 20 females; mean age = 21.2 ± 1.0 years) participated in the study. TSST was used to induce acute psychosocial stress. PPT, subjective stress, and autonomic activity (pulse wave amplitude and length) were assessed at three time points: pre, post, and 10-min recovery. Social skills were measured using the Adult Social Skills Scale, and trait anxiety was assessed using the STAI. Linear mixed-effects and regression models were applied to examine time effects and anxiety’s moderating role. Results Subjective stress increased significantly immediately after TSST and returned to near baseline at the 10-min recovery. No significant changes were observed in pulse wave amplitude or length. A linear mixed-effects model revealed no significant main effect of time (F(2, 64) = 0.01, p = .99) or interaction between time and total social skills (F(2, 64) = 0.03, p = .97). A trend-level main effect of total social skills was observed (F(1, 31) = 3.28, p = .08), indicating that higher social skills were associated with greater PPT overall. Regression analyses of subscales revealed that only encoding skill exhibited a trend-level association with pre-to-post PPT change. A subsequent interaction model established a significant moderation by trait anxiety: the protective association of encoding skill with increased PPT was significant among low to average anxiety participants but not among high-anxiety participants. Conclusions Individuals with higher social skills, particularly those with effective encoding abilities and lower trait anxiety, exhibited greater pain tolerance under stress, although acute social stress did not produce an overall change in PPT. These findings suggest that social communication competence may serve as a resilience factor in stress-related pain modulation, although elevated anxiety levels may attenuate such benefits.

Yuzheng Ke, Fenglu Han, Walter G. Joyce

Pan-trionychids are a group of aquatic turtles with a geological occurrence from the Early Cretaceous to the present. Here, we report a small pan-trionychid specimen from the Upper Cretaceous Zhoutian Formation of the Ganzhou Basin of Jiangxi Province, China, which consists of a nearly complete carapace and several associated fragments. The specimen is the first definitive pan-trionychid record from the Upper Cretaceous of southern China. Its general skeletal features are comparable with those of other pan-trionychids from the mid Cretaceous of Asia. However, because the specimen appears to be a juvenile and lacks sufficient anatomical details, we refrain from naming a new species or hypothesizing phylogenetic relationships. Upper Cretaceous sediments in the Ganzhou Basin document a succession of turtle faunas ranging from aquatic pan-trionychids to semi-aquatic lindholmemydids to possibly terrestrial nanhsiungchelyids, but the relationship between this succession and paleoclimate remains ambiguous.

Daniela Peña Aguilera, Emma Alfaro Gómez

Se presenta un análisis descriptivo del comportamiento demográfico de Cochinoca, población ubicada en la zona central de la Puna de Jujuy, República Argentina, realizado a partir de fuentes de recuento que van desde 1654 a 2010, divididas en tres períodos: colonial, histórico y actual. Se analizó la composición general, evaluando el tamaño poblacional, la estructura sexual y la estructura etaria, relacionando lo observado con el contexto sociopolítico de cada período. Se registró una población en crecimiento, joven considerando la gran cantidad de infantes durante todo el lapso observado, y con una fuerza de trabajo robusta representada por los adultos y jóvenes de ambos sexos. También se observó una porción envejecida considerable, con mayor representación femenina en los tres períodos. Inicialmente la conformación sexual fue equilibrada, para luego presentar un desequilibrio marcado, situación relacionada posiblemente a migraciones laborales masculinas y a eventos bélicos ocurridos durante el siglo XIX. Las fuentes consultadas resultaron adecuadas para evaluar aspectos demográficos generales recorriendo al menos tres siglos, observando fenómenos de larga duración en una población en constante cambio y adecuándose a la coyuntura de cada fase analizada.

Heather F. Smith, Brent Adrian, Patrick Kline

Abstract The marine turtle family Ctenochelyidae was a Late Cretaceous North American radiation of Pan-Chelonioidea, broadly distributed along the coastlines of the Atlantic Coastal Plain and Mississippi Embayment. Here, we describe a large, mostly articulated carapace representing a novel species of the ctenochelyid genus Asmodochelys from the Maastrichtian Neylandville Marl Formation in north central Texas. The specimen is diagnosed as a ctenochelyid by its large cordiform carapace with a broad nuchal embayment, prominent neural keel with epineural ossifications, and costoperipheral fontanelles. It has a unique combination of characters: large size (~ 120 cm); epineurals dorsal to N1/2, N3/4, N5/6, and N7/8; robust articulation between costal 1 and peripherals 1–2; lack of postnuchal fontanelles; pronounced anterior horn-like projection of peripheral 1; weakly scalloped posterior peripherals. Maximum parsimony phylogenetic analyses were conducted in TNT v1.6, and in the resulting majority-rule consensus trees, the specimen was positioned at the base of Ctenochelyidae in an unresolved polytomy with Asmodochelys parhami and the unresolved clade of (Peritresius ornatus + Prionochelys matutina + Ctenochelys acris + Ctenochelys stenoporus). The Neylandville Marl lies within the faunal zone of the marine oyster Exogyra cancellata, providing a particular marine ecological context that extends from Mexico to New Jersey. The new species extends the stratigraphic range of Asmodochelys into the Maastrichtian of the Gulfian Series, and geographically further west of the Mississippi Embayment to north-central Texas. It is one of the latest surviving members of the Ctenochelyidae persisting into the Maastrichtian, a time of global climatic cooling when other major Campanian marine turtle lineages, such as protostegids and Toxochelys-like early stem-chelonioids faced extinction.

Giuseppe Vecchio, Adrien Kaiser, Rouffet Romain et al.

Foundation models have emerged as effective backbones for many vision tasks. However, current self-supervised features entangle high-level semantics with low-level physical factors, such as geometry and illumination, hindering their use in tasks requiring explicit physical reasoning. In this paper, we introduce $Φ$eat, a novel physically-grounded visual backbone that encourages a representation sensitive to material identity, including reflectance cues and geometric mesostructure. Our key idea is to employ a pretraining strategy that contrasts spatial crops and physical augmentations of the same material under varying shapes and lighting conditions. While similar data have been used in high-end supervised tasks such as intrinsic decomposition or material estimation, we demonstrate that a pure self-supervised training strategy, without explicit labels, already provides a strong prior for tasks requiring robust features invariant to external physical factors. We evaluate the learned representations through feature similarity analysis and material selection, showing that $Φ$eat captures physically-grounded structure beyond semantic grouping. These findings highlight the promise of unsupervised physical feature learning as a foundation for physics-aware perception in vision and graphics. These findings highlight the promise of unsupervised physical feature learning as a foundation for physics-aware perception in vision and graphics.

Congyue Deng, Brandon Y. Feng, Cecilia Garraffo et al.

Machine learning frameworks for physical problems must capture and enforce physical constraints that preserve the structure of dynamical systems. Many existing approaches achieve this by integrating physical operators into neural networks. While these methods offer theoretical guarantees, they face two key limitations: (i) they primarily model local relations between adjacent time steps, overlooking longer-range or higher-level physical interactions, and (ii) they focus on forward simulation while neglecting broader physical reasoning tasks. We propose the Denoising Hamiltonian Network (DHN), a novel framework that generalizes Hamiltonian mechanics operators into more flexible neural operators. DHN captures non-local temporal relationships and mitigates numerical integration errors through a denoising mechanism. DHN also supports multi-system modeling with a global conditioning mechanism. We demonstrate its effectiveness and flexibility across three diverse physical reasoning tasks with distinct inputs and outputs.

Hyunmin Cheong, Adrian Butscher

The current work presents an ontology developed for physics-based simulation in engineering design, called Physics-based Simulation Ontology (PSO). The purpose of the ontology is to assist in modelling the physical phenomenon of interest in a veridical manner, while capturing the necessary and reusable information for physics-based simulation solvers. The development involved extending an existing upper ontology, Basic Formal Ontology (BFO), to define lower-level terms of PSO. PSO has two parts: PSO-Physics, which consists of terms and relations used to model physical phenomena based on the perspective of classical mechanics involving partial differential equations, and PSO-Sim, which consists of terms used to represent the information artefacts that are about the physical phenomena modelled with PSO-Physics. The former terms are used to model the physical phenomenon of interest independent of solver-specific interpretations, which can be reused across different solvers, while the latter terms are used to instantiate solver-specific input data. A case study involving two simulation solvers was conducted to demonstrate this capability of PSO. Discussion around the benefits and limitations of using BFO for the current work is also provided, which should be valuable for any future work that extends an existing upper ontology to develop ontologies for engineering applications.

Rio Alexa Fear, Payel Mukhopadhyay, Michael McCabe et al.

Recent advances in mechanistic interpretability have revealed that large language models (LLMs) develop internal representations corresponding not only to concrete entities but also distinct, human-understandable abstract concepts and behaviour. Moreover, these hidden features can be directly manipulated to steer model behaviour. However, it remains an open question whether this phenomenon is unique to models trained on inherently structured data (ie. language, images) or if it is a general property of foundation models. In this work, we investigate the internal representations of a large physics-focused foundation model. Inspired by recent work identifying single directions in activation space for complex behaviours in LLMs, we extract activation vectors from the model during forward passes over simulation datasets for different physical regimes. We then compute "delta" representations between the two regimes. These delta tensors act as concept directions in activation space, encoding specific physical features. By injecting these concept directions back into the model during inference, we can steer its predictions, demonstrating causal control over physical behaviours, such as inducing or removing some particular physical feature from a simulation. These results suggest that scientific foundation models learn generalised representations of physical principles. They do not merely rely on superficial correlations and patterns in the simulations. Our findings open new avenues for understanding and controlling scientific foundation models and has implications for AI-enabled scientific discovery.

Wen Yin, Jian Lou, Pan Zhou et al.

Backdoor attacks have been well-studied in visible light object detection (VLOD) in recent years. However, VLOD can not effectively work in dark and temperature-sensitive scenarios. Instead, thermal infrared object detection (TIOD) is the most accessible and practical in such environments. In this paper, our team is the first to investigate the security vulnerabilities associated with TIOD in the context of backdoor attacks, spanning both the digital and physical realms. We introduce two novel types of backdoor attacks on TIOD, each offering unique capabilities: Object-affecting Attack and Range-affecting Attack. We conduct a comprehensive analysis of key factors influencing trigger design, which include temperature, size, material, and concealment. These factors, especially temperature, significantly impact the efficacy of backdoor attacks on TIOD. A thorough understanding of these factors will serve as a foundation for designing physical triggers and temperature controlling experiments. Our study includes extensive experiments conducted in both digital and physical environments. In the digital realm, we evaluate our approach using benchmark datasets for TIOD, achieving an Attack Success Rate (ASR) of up to 98.21%. In the physical realm, we test our approach in two real-world settings: a traffic intersection and a parking lot, using a thermal infrared camera. Here, we attain an ASR of up to 98.38%.

Floyd W. Stecker

This book chapter presents an overview of the historical experimental and theoretical developments in neutrino physics and astrophysics and also the physical properties of neutrinos, as well as the physical processes involving neutrinos. It also discusses the role of neutrinos in astrophysics and cosmology. Correction to tex file made.

Gonzalo Garizoain, Marcos Plischuk, Susana Alicia Salceda et al.

La edad cronológica es una de las características que puede estimarse mediante el análisis de los dientes. Algunos de los métodos más utilizados para su estimación, tal como el basado en la translucidez de la dentina, emplean variables continuas, por lo que suelen aplicar regresiones lineales. Sin embargo, es conocido que muchos indicadores morfológicos varían de manera no lineal con respecto a la edad. En este sentido ha sido demostrado que en ciertos segmentos de la distribución de datos la edad no se ajusta de manera precisa a la recta de la regresión. A raíz de la problemática suscitada, se analizarán en este trabajo dos modelos de estimación de la edad basados en regresiones, una lineal y otra logarítmica. En primer lugar, se generaron los modelos a partir de medidas de translucidez de la raíz en caninos inferiores permanentes a partir del método propuesto por Lamendin, para lo cual se tomó una muestra de dientes pertenecientes a restos esqueléticos de la colección Lambre (La Plata, Argentina). Posteriormente dichos modelos se evaluaron en una muestra independiente (colección Museo Anatómico, Valladolid, España). La edad resultó ser un factor de incidencia en las estimaciones, aumentando el error en los individuos de edades avanzadas. Por otro lado, el modelo logarítmico presentó menores errores en las estimaciones aplicado a la muestra general.

AUBREY JANE ROBERTS, VICTORIA SJØHOLT ENGELSCHIØN, JØRN HARALD HURUM

The marine Middle Triassic sediments of Svalbard are rich in fossiliferous material and are particularly well-known for marine reptile fossils. Here, we present a new specimen of the small-bodied mixosaurid ichthyosaur Phalarodon fraasi from the Botneheia Formation. PMO 235.393 is unusual in being the first three-dimensional mixosaurid skull recovered from this formation, allowing us to use computed tomography to reconstruct the obscured right side of the cranium, resulting in the first 3D model available for a mixosaurid ichthyosaur. Although separated into different slabs, the specimen preserves most of the dermatocranium as well as some partial post-cranial elements. In particular, the rostrum, external naris, dentition, quadrate and sclerotic ring are well-preserved. This methodology gave new insights into the adaptations this taxon has to durophagy, as well as a detailed look at the heterodont dentition present in PMO 235.393. After comparing with other Phalarodon specimens, it was clear that the maxillary heterodonty of this genus is a synapomorphy. As such this was added as a new character in our phylogenetic analysis, supporting the separation of Phalarodon and Mixosaurus.

Shiqian Li, Kewen Wu, Chi Zhang et al.

Is dynamics prediction indispensable for physical reasoning? If so, what kind of roles do the dynamics prediction modules play during the physical reasoning process? Most studies focus on designing dynamics prediction networks and treating physical reasoning as a downstream task without investigating the questions above, taking for granted that the designed dynamics prediction would undoubtedly help the reasoning process. In this work, we take a closer look at this assumption, exploring this fundamental hypothesis by comparing two learning mechanisms: Learning from Dynamics (LfD) and Learning from Intuition (LfI). In the first experiment, we directly examine and compare these two mechanisms. Results show a surprising finding: Simple LfI is better than or on par with state-of-the-art LfD. This observation leads to the second experiment with Ground-truth Dynamics, the ideal case of LfD wherein dynamics are obtained directly from a simulator. Results show that dynamics, if directly given instead of approximated, would achieve much higher performance than LfI alone on physical reasoning; this essentially serves as the performance upper bound. Yet practically, LfD mechanism can only predict Approximate Dynamics using dynamics learning modules that mimic the physical laws, making the following downstream physical reasoning modules degenerate into the LfI paradigm; see the third experiment. We note that this issue is hard to mitigate, as dynamics prediction errors inevitably accumulate in the long horizon. Finally, in the fourth experiment, we note that LfI, the extremely simpler strategy when done right, is more effective in learning to solve physical reasoning problems. Taken together, the results on the challenging benchmark of PHYRE show that LfI is, if not better, as good as LfD for dynamics prediction. However, the potential improvement from LfD, though challenging, remains lucrative.

Eric Capo, Charline Giguet-Covex, Alexandra Rouillard et al.

The use of lake sedimentary DNA to track the long-term changes in both terrestrial and aquatic biota is a rapidly advancing field in paleoecological research. Although largely applied nowadays, knowledge gaps remain in this field and there is therefore still research to be conducted to ensure the reliability of the sedimentary DNA signal. Building on the most recent literature and seven original case studies, we synthesize the state-of-the-art analytical procedures for effective sampling, extraction, amplification, quantification and/or generation of DNA inventories from sedimentary ancient DNA (sedaDNA) via high-throughput sequencing technologies. We provide recommendations based on current knowledge and best practises.

Karalee Miller

This article by no means serves to account for theories on virtual technologies or virtual design but, rather, offers a distinct exploration on the role of the body in virtual experiences and spaces. Selected works account for embodiment literature and emergent considerations of the body in what may be considered a post-body, or post-human, era of technology, connectivity, and communications. This list includes work that researches, discusses, or questions notions of virtual with regard to landscapes of experience and that looks to discourses on the role of the body in human perception. With implications for larger questions regarding the human mind, and apart from dualistic conversations on mind-body connections, embodiment theories view the body as a tool for participation in lifeworlds. Embodiment is inherently a social concept, and one that rests on foundational understandings of human evolution and adaptation as well as human sociability and socialization, sometimes explored as ecosocial phenomena. Conjuring many inquiries in biology, cognition, psychology, ethics, philosophy, religion, and ecology, this collection is composed mostly of work in the humanities and social sciences and is skewed by traditions in anthropology. It is generally well accepted that cultural perspectives inform human knowledge, but theories in embodiment ask how social and cultural conditions inform not only perspectives, but also experiences or felt senses (or both). Questions of materiality give way to attention on the physical, earthly environment to which humans have evolved and with which humans have coadapted. Scholars have referred to this era as the Anthropocene, which ultimately points to human dilemma, since human behavior is defined by progressively more destructive behavior that yields an earth on which humans cannot rely for resources. Simultaneously, media, entertainment, and design technology have moved into virtual reality and augmented experiences that either transcend, mimic, or escape earthly realms or physical limitations. Simulated or virtual experiences make use of what we know about human perception to create new forms of reality. Theories of being and knowing, inherent to the anthropological canon, pose examination of bodily knowledge and bring about inquiry in medicine, disability studies, cognition, and health, to name a few. Mediated and augmented experiences have all manner of applications and implications, including overriding biology and genetics, posing questions for the future of the human condition. This article includes new work from science journals and popular media to illustrate how new human adaptations, ecologies, and virtual perceptions interface with embodiment.

Laia Comas-Bru, Sandy P. Harrison

Isotopic records from speleothems are an important source of information about past climates and, given the increase in the number of isotope-enabled climate models, are likely to become an important tool for climate model evaluation. SISAL (Speleothem Isotopes Synthesis and Analysis) have created a global database of isotopic records from speleothems in order to facilitate regional analyses and data-model comparison. The papers in this Special Issue showcase the use of the database for regional analyses. In this paper, we discuss some of the important issues underpinning the use of speleothems and how the existence of this database assists palaeoclimate research. We also highlight some of the lessons learned in the creation of the SISAL database and outline potential research going forward.

Thomas Schubnel, Andre Nel

Mantodea are rather scarce in the fossil record, especially those belonging to the mantise crown group. Four fossil mantids are described from the lowermost Eocene amber of Oise (France), two Chaeteessidae considered as “genus and species incertae sedis”, and two Mantoididae, described as a new genus and species Pseudomantoida extendidera. We also describe a new specimen of Arvernineura insignis from the Paleocene of Menat (France), confirming the attribution of this taxon to the Chaeteessidae. These fossils are of great interest for future dating of the crown group Mantodea, being the oldest Chaeteessidae and Mantoididae. We propose a new genus name Louispitonia nom. nov. in replacement of Archaeophlebia Piton, 1940 preoccupied by Archaeophlebia Ris, 1909 (Odonata) with Archaeophlebia enigmatica as its type species.

Craig Lage

Removing systematic effects from astronomical images taken with CCDs requires a detailed understanding of the physics of the imaging process. To aid in this understanding, we have built detailed electrostatic simulations of the LSST CCDs. In order to build an electrostatic model of the LSST CCDs, physical information about the CCDs is required. These details include things such as the physical dimensions of the components of the CCD, dopant profiles, and in some cases, electrical measurements of the CCD. This work documents the results of these physical and electrical measurements on LSST CCDs.

Maxim Yu. Khlopov

The lack of experimental evidence at the LHC for physics beyond the Standard model (BSM) of elementary particles together with necessity of its existence to provide solutions of internal problems of the Standard model (SM) as well as of physical nature of the basic elements of the modern cosmology demonstrates the conspiracy of BSM physics. Simultaneously the data of precision cosmology only tighten the constraints on the deviations from the now standard LambdaCDM model and thus exhibit conspiracy of the nonstandard cosmological scenarios. We show that studying new physics in combination of its physical, astrophysical and cosmological probes, can not only unveil the conspiracy of BSM physics but will also inevitably reveal nonstandard features in the cosmological scenario.

Robert Geroch, James B. Hartle

The familiar theories of physics have the feature that the application of the theory to make predictions in specific circumstances can be done by means of an algorithm. We propose a more precise formulation of this feature --- one based on the issue of whether or not the physically measurable numbers predicted by the theory are computable in the mathematical sense. Applying this formulation to one approach to a quantum theory of gravity, there are found indications that there may exist no such algorithms in this case. Finally, we discuss the issue of whether the existence of an algorithm to implement a theory should be adopted as a criterion for acceptable physical theories.