Hasil untuk "Physical anthropology. Somatology"

Arnaud Begat, Eduardo Villalobos-Segura, Manuel Amadori et al.

The majority of the fossil records of elasmobranch fishes (sharks, rays, skates) consists of isolated teeth and dermal denticles. Over their long and complex evolutionary history, dental remains are particularly indicative of the group’s plasticity and adaptability, which has hampered the classification of fossil species with highly specialised dental morphologies that deviate from those of extant species. One of such cases is †Synechodus prorogatus recovered from Middle and Late Jurassic deposits in Poland and Germany. Its original description and diagnosis were based on a single complete and two very incomplete teeth, which showed a very peculiar morphology with some features resembling several groups. These similarities resulted in its placement within synechodontiforms. However, subsequent findings showing numerous differences with the type species of the genus, †Synechodus dubrisiensis, cast doubt on its assignment within this group and this genus. Here, we describe new material from Upper Jurassic offshore deposits in SW Germany, which provides additional information about this species. We conducted a comprehensive morphological comparison between †S. prorogatus, various Jurassic selachian taxa and the type species of †Synechodus, †S. dubrisiensis (Late Cretaceous, England), confirming the taxonomic distinctiveness of this Jurassic species, which requires the establishment of a new genus, †Curvorudentis, with †C. prorogatus gen. et comb. nov. being type species. The discovery of this taxon in Late Jurassic deposits of Germany represents its stratigraphically youngest occurrence, extending its chronostratigraphic range and geographical distribution. †Curvorudentis prorogatus is considered here a galeomorph shark, rather than being a member of the stem clade †Synechodontiformes, although its precise systematic position within this group remains ambiguous.

Facundo Javier Riguetti, Sebastián Apesteguía, Juan Ignacio Canale et al.

South American Mesozoic vertebrate fossils are key in contrasting the classic North American and European views of clades evolution. During the last decades, several relevant findings of stegosaurian remains from Argentina show a greater diversity than previously thought. These include the early stegosaur Isaberrysaura from Los Molles Formation (Middle Jurassic) and indeterminate stegosaurian remains from the Cañadón Calcáreo (Upper Jurassic) and the La Amarga (Lower Cretaceous) formations, all from the Argentinian Patagonia. In addition to these scarce records, new remains from the Berriasian–Valanginian Bajada Colorada Formation of Neuquén Province (Argentina) are presented here. These consist of sacral vertebrae, dorsal ribs and several osteoderm types, including stegosaurian-like spines. The shape analysis of the sacral vertebrae, anatomic features (e.g., sacral vertebrae and ribs dorsoventrally compressed, and dorsal ribs with T-shaped proximal transversal section), and the morphologic disparity of the osteoderms, support an assignation to Thyreophora with affinities to Stegosauria. The finding of these remains in Bajada Colorada reinforces the presence of stegosaurs in Argentinian Patagonia during the Lower Cretaceous. Our explorations and research in Bajada Colorada also support that the historical absence of stegosaurian remains in Southern continents was an effect of searching and/or preservational biases, as other authors proposed. These new stegosaurian remains also support the presence of a transitional fauna in Bajada Colorada including both Jurassic and Cretaceous components.

Helen Qu, Rudy Morel, Michael McCabe et al.

Machine learning approaches to spatiotemporal physical systems have primarily focused on next-frame prediction, with the goal of learning an accurate emulator for the system's evolution in time. However, these emulators are computationally expensive to train and are subject to performance pitfalls, such as compounding errors during autoregressive rollout. In this work, we take a different perspective and look at scientific tasks further downstream of predicting the next frame, such as estimation of a system's governing physical parameters. Accuracy on these tasks offers a uniquely quantifiable glimpse into the physical relevance of the representations of these models. We evaluate the effectiveness of general-purpose self-supervised methods in learning physics-grounded representations that are useful for downstream scientific tasks. Surprisingly, we find that not all methods designed for physical modeling outperform generic self-supervised learning methods on these tasks, and methods that learn in the latent space (e.g., joint embedding predictive architectures, or JEPAs) outperform those optimizing pixel-level prediction objectives. Code is available at https://github.com/helenqu/physical-representation-learning.

Denis Theda, Darius Nau, René Dederichs et al.

Ornithomimosauria is a group of coelurosaurs primarily known from the Cretaceous of Asia and North America. The European record is comparatively sparse, with Pelecanimimus from the Lower Cretaceous of Spain being the only unequivocal representative. Here, we present a manual ungual and a distal metatarsal III from a Lower Cretaceous (Barremian to Aptian) karstic fissure fill in Balve, northwestern Germany, which we assign to Ornithomimosauria indet. We also review the literature regarding manual unguals of ornithomimosaurs and confirm previous reports of quite consistent positional variation within Ornithomimosauria, with manual ungual I being the most recurved and bearing the largest flexor tubercle, and the unguals of digits II and III being less recurved and possessing smaller tubercles. The manual ungual from Balve is closest in morphology to manual digit III. The metatarsal has a shaft with a strongly triangular cross-section, marking it as a sub- or fully developed arctometatarsal. This type of specialized third metatarsal occurs in a number of different clades of Coelurosauria (Alvarezsauroidea, Ornithomimosauria, Oviraptorosauria, Troodontidae, Tyrannosauridae). Based on its overall morphology and the rarity (Alvarezsauroidea, Troodontidae) or absence (Oviraptorosauria, Tyrannosauridae) of other clades with arctometatarsals from the fossil record of Europe, we regard it as ornithomimosaurian. This is only the second definitive record of European ornithomimosaurs, after the description of Pelecanimimus polyodon from Spain, and represents the first reported occurrence of this clade in Germany.

Jia-Xin Xiong, Xiuwen Zhang, Lin-Ding Yuan et al.

Materials with interesting physical properties are often designed based on our understanding of the target physical effects. The physical properties can be either explicitly observed ("apparent") or concealed by the perceived symmetry ("hidden") but still exist. Both are enabled by specific symmetries and induced by certain physical interactions. Using the underlying approach of condensed matter theory of real materials (rather than schematic model Hamiltonians), we discuss apparent and hidden physics in real materials focusing on the properties of spin splitting and spin polarization. Depending on the enabling symmetries and underlying physical interactions, we classify spin effects into four categories with each having two subtypes; representative materials are pointed out. We then discuss the electric tunability and switch of apparent and hidden spin splitting and polarization in antiferromagnets. Finally, we extend "hidden effects" to views that are farsighted in the sense of resolving the correct atomistic and reciprocal symmetry and replaced by the incorrect higher symmetry. This framework could guide and enable systematic discovery of such intriguing effects.

Yuqiu Liu, Huanqian Yan, Xiaopei Zhu et al.

Recently we have witnessed progress in hiding road vehicles against object detectors through adversarial camouflage in the digital world. The extension of this technique to the physical world is crucial for testing the robustness of autonomous driving systems. However, existing methods do not show good performances when applied to the physical world. This is partly due to insufficient photorealism in training examples, and lack of proper physical realization methods for camouflage. To generate a robust adversarial camouflage suitable for real vehicles, we propose a novel method called PAV-Camou. We propose to adjust the mapping from the coordinates in the 2D map to those of corresponding 3D model. This process is critical for mitigating texture distortion and ensuring the camouflage's effectiveness when applied in the real world. Then we combine two renderers with different characteristics to obtain adversarial examples that are photorealistic that closely mimic real-world lighting and texture properties. The method ensures that the generated textures remain effective under diverse environmental conditions. Our adversarial camouflage can be optimized and printed in the form of 2D patterns, allowing for direct application on real vehicles. Extensive experiments demonstrated that our proposed method achieved good performance in both the digital world and the physical world.

Ryan Nichols, Mathieu Charbonneau, Azita Chellappoo et al.

The rapid growth of cultural evolutionary science, its expansion into numerous fields, its use of diverse methods, and several conceptual problems have outpaced corollary developments in theory and philosophy of science. This has led to concern, exemplified in results from a recent survey conducted with members of the Cultural Evolution Society, that the field lacks ‘knowledge synthesis’, is poorly supported by ‘theory’, has an ambiguous relation to biological evolution and uses key terms (e.g. ‘culture’, ‘social learning’, ‘cumulative culture’) in ways that hamper operationalization in models, experiments and field studies. Although numerous review papers in the field represent and categorize its empirical findings, the field's theoretical challenges receive less critical attention even though challenges of a theoretical or conceptual nature underlie most of the problems identified by Cultural Evolution Society members. Guided by the heterogeneous ‘grand challenges’ emergent in this survey, this paper restates those challenges and adopts an organizational style requisite to discussion of them. The paper's goal is to contribute to increasing conceptual clarity and theoretical discernment around the most pressing challenges facing the field of cultural evolutionary science. It will be of most interest to cultural evolutionary scientists, theoreticians, philosophers of science and interdisciplinary researchers.

Ronald J. Planer, Ross Pain

Theorists of human evolution are interested in understanding major shifts in human behavioural capacities (e.g. the creation of a novel technological industry, such as the Acheulean). This task faces empirical challenges arising both from the complexity of these events and the time-depths involved. However, we also confront issues of a more philosophical nature, such as how to best think about causation and explanation. This article considers such fundamental questions from the perspective of a prominent theory of causation in the philosophy of science literature, namely, the interventionist theory of causation. A signature feature of this framework is its recognition of a family of distinct types of causes. We set out several of these causal notions and show how they can contribute to explaining transitions in human behavioural complexity. We do so, first, in a preliminary way, and then in a more detailed way, taking the origins of behavioural modernity as our extended case study. We conclude by suggesting some ways in which the approach developed here might be elaborated and extended.

Alessio Iannucci, Piroska Pazonyi, Krisztina Sebe

Abstract Sus arvernensis is a Pliocene species that occupies a key position in the evolution of suids (Suidae, Artiodactyla, Mammalia) in Eurasia, and besides, it is considered important for biochronological correlations and paleoecological inferences. However, our knowledge on S. arvernensis is largely based on fossil remains from southwestern Europe. Here, we present a revision of the Hungarian fossil record of S. arvernensis. Up to now, the species was known from only two localities of Hungary, Gödöllő (central Hungary) and Süttő (northwest Hungary), and the latter occurrence has even been questioned. After the comparison with other relevant samples of S. arvernensis, of the Early Pleistocene S. strozzii, and of the extant wild boar S. scrofa (motivated by previous attributions and the chronology of the localities), the presence of S. arvernensis from Gödöllő and Süttő is confirmed, and more material of the species is described from Beremend (southern Hungary) and Kisláng (western Hungary). Collectively, the results of the revision carried out herein reveal a relatively widespread distribution of S. arvernensis in Hungary, hence providing an important link from the eastern to western European fossil record of the species. The specimens from Gödöllő and Süttő are slightly larger than the other material of S. arvernensis from France and Italy included in the biometric comparison, although the paucity of the material precludes to evaluate whether these differences are significant and to relate them to a chronological and/or geographical context. The occurrence of S. arvernensis in the Hungarian localities considered in this work is a biochronological indication of an age older than at least 2.6 Ma, since the species is not recorded after the Pliocene–Pleistocene transition. This in agreement with the age estimates available so far for some of the localities or provides new insights. At Süttő, in particular, the identification of S. arvernensis reinforces the view that travertine deposition started already in the Pliocene.

Wen-Jie Tseng

Virtual Reality (VR) moves away from well-controlled laboratory environments into public and personal spaces. As users are visually disconnected from the physical environment, interacting in an uncontrolled space frequently leads to collisions and raises safety concerns. In my thesis, I investigate this phenomenon which I define as the physical breakdown in VR. The goal is to understand the reasons for physical breakdowns, provide solutions, and explore future mechanisms that could perpetuate safety risks. First, I explored the reasons for physical breakdowns by investigating how people interact with the current VR safety mechanism (e.g., Oculus Guardian). Results show one reason for breaking out of the safety boundary is when interacting with large motions (e.g., swinging arms), the user does not have enough time to react although they see the safety boundary. I proposed a solution, FingerMapper, that maps small-scale finger motions onto virtual arms and hands to enable whole-body virtual arm motions in VR to avoid physical breakdowns. To demonstrate future safety risks, I explored the malicious use of perceptual manipulations (e.g., redirection techniques) in VR, which could deliberately create physical breakdowns without users noticing. Results indicate further open challenges about the cognitive process of how users comprehend their physical environment when they are blindfolded in VR.

Taha Sochi

This is the first of a series of papers that we intend to publish about the epistemology of fundamental physics in its current state. One of the main objectives of these papers is to improve our understanding of fundamental physics (and modern physics in particular) from an epistemological and interpretative perspective (i.e. versus formal perspective). Another main objective is to investigate and assess the merit of searching for a unified physical theory (the so-called ``theory of everything'') considering the fact that contemporary physics is a collection of theories created and developed by different individuals and groups of scientists in different eras of history reflecting different levels of scientific, philosophical and epistemological development and dealing with largely separate physical phenomena and hence such unification may mean ``stitching together'' an inhomogeneous collection of theoretical structures which may be clumsy (if not impossible) at least from an epistemological viewpoint.

Slobodan B. Marković, Jef Vandenberghe, Zoran M. Perić et al.

Typical patterns of the Late Pleistocene loess–paleosol units are preserved in the Novo Orahovo brickyard, Northern Serbia. Presented preliminary luminescence chronology supports the chronostratigraphic interpretations of global isotopic marine climate reconstructions. Magnetic susceptibility and sedimentological evidence exhibit general similarities with the marine oxygen-isotope stratigraphy. These records provide new insights into the dust accumulation regimes over the eastern side of the Bačka loess plateau and offer new paleoenvironmental information for the region. They represent an important step forward towards the establishment of a catena from the thin loess-like sediments of the Banat foothills in the east towards the thicker and seemingly more complete loess sections of the southeastern and central Carpathian Basin. Grain-size data from the loess record of Nova Orahovo explain the regional differentiation in dust deposition.

Колясникова А.С. , Бужилова А.П.

Введение. Лобный внутренний гиперостоз (далее HFI), это патологическое состояние, характеризующееся разрастанием внутренней поверхности лобной кости. В настоящее время большинство исследователей описывают HFI как сопутствующий гормональным дисфункциям признак, который преобладает у современного населения. Также было отмечено, что лобный внутренний гиперостоз может быть ассоциирован с метаболическими нарушениями и иметь наследственный характер. Целью данной работы является оценка частоты встречаемости HFI на краниологическом материале представителей четырех адаптивных типов. Материалы и методы. Исследовано 2211 черепов представителей четырех адаптивных типов – арктического, тропического, умеренного и континентального (59 краниологических коллекций из фондов НИИ и Музея антропологии МГУ, Музея антропологии и этнографии имени Петра Великого РАН и фондов ФИЦ ТюмНЦ СО РАН). Анализировалась общая частота встречаемости признака и с учетом степени его развития (4-х балльная оценка), проведен сравнительный межгрупповой анализ. Результаты и обсуждение. Было обнаружено, что частота встречаемости HFI в группах представителей арктического, континентального и умеренного адаптивных типов варьирует от 2,3% до 4,3%, что значительно меньше, чем у современного населения (12-37%). У представителей тропического адаптивного типа HFI обнаружен не был. В исследованных выборках самым распространенным оказался тип А, реже был отмечен HFI тип B, а тип С зафиксирован только у одного индивидуума арктического адаптивного типа. На примере исследованных групп обсуждаются причины относительно низкого распространения HFI у представителей различных адаптивных типов. Заключение. Учитывая одинаково низкие значения HFI в группах всех изученных адаптивных типов, относительно современных групп, можно предположить, что адаптация к условиям окружающей среды и образу жизни несет больший вклад в развитие лобного внутреннего гиперостоза, нежели сугубо климатические и географические особенности.

R.I.M. Dunbar

Doctrinal religions that involve recognised gods, more formal theologies, moral codes, dedicated religious spaces and professional priesthoods emerged in two phases during the Neolithic. Almost all of these appeared in a narrow latitudinal band (the northern Subtropical Zone). I suggest that these developments were the result of a need to facilitate community bonding in response to scalar stresses that developed as community sizes increased dramatically beyond those typical of hunter–gatherer societies. Conditions for population growth (as indexed by rainfall patterns and the difference between pathogen load and the length of the growing season) were uniquely optimised in this zone, creating an environment of ecological release in which populations could grow unusually rapidly. The relationship between latitude, religion and language in contemporary societies suggests that the peculiar characteristics of the northern (but not the southern) Subtropical Zone were especially favourable for the evolution of large scale religions as a way of enforcing community cohesion.

Leonardo Salgado

Los museos e instituciones científicas de Río Negro jugaron un rol importante en el desarrollo de estudios paleoherpetológicos. Dichos estudios fueron mayormente conducidos por profesionales de instituciones de otras partes del país. No obstante, la mayoría de las instituciones rionegrinas constituyen un soporte importante, tanto como repositorios de los materiales recolectados como en su accionar como apoyo logístico en la organización de tareas de campo y asistencia a las investigaciones. Varias de las instituciones de Río Negro cuentan con su propio personal de investigación. Gran parte de los estudios realizados se centran mayormente en herpetofauna de edad cretácica, aunque también involucran algunos materiales del Cenozoico.

George F R Ellis

This is a comment on both Gruber et al (2022) and Bunamano and Rovelli (2022), which discuss the relation between physical time and human time. I claim here, contrary to many views discussed there, that there is no foundational conflict between the way physics views the passage of time and the way the mind/brain perceives it. The problem rather resides in a number of misconceptions leading to the representation of spacetime as a timeless Block Universe. The physical expanding universe is in fact an Evolving Block Universe with a time-dependent future boundary. This establishes a global direction of time that determines local arrows of time. Furthermore time passes when quantum wave function collapse takes place; during this process, information is lost. The mind/brain acts as an imperfect clock, which coarse-grains the physical passage of time along a world line to determine the experienced passage of time, because neuronal processes take time to occur. This happens in a contextual way, so experienced time is not linearly related to physical time in general. Finally I point out that the Universe is never infinitely old: its future endpoint always lies infinitely faraway in the future

Jiaqi Huang

Symmetry lies at the heart of todays theoretical study of particle physics. Our manuscript is a tutorial introducing foundational mathematics for understanding physical symmetries. We start from basic group theory and representation theory. We then introduce Lie Groups and Lie Algebra and their properties. We next discuss with detail two important Lie Groups in physics Special Unitary and Lorentz Group, with an emphasis on their applications to particle physics. Finally, we introduce field theory and its version of the Noether Theorem. We believe that the materials cover here will prepare undergraduates for future studies in mathematical physics.

Sien Thys, Maarten Van Daele, Nore Praet et al.

Snow avalanches cause many fatalities every year and damage local economies worldwide. The present-day climate change affects the snowpack and, thus, the properties and frequency of snow avalanches. Reconstructing snow avalanche records can help us understand past variations in avalanche frequency and their relationship to climate change. Previous avalanche records have primarily been reconstructed using dendrochronology. Here, we investigate the potential of lake sediments to record snow avalanches by studying 27 < 30-cm-long sediment cores from Kenai Lake, south-central Alaska. We use X-ray computed tomography (CT) to image post-1964 varves and to identify dropstones. We use two newly identified cryptotephras to update the existing varve chronology. Satellite imagery is used to understand the redistribution of sediments by ice floes over the lake, which helps to explain why some avalanches are not recorded. Finally, we compare the dropstone record with climate data to show that snow avalanche activity is related to high amounts of snowfall in periods of relatively warm or variable temperature conditions. We show, for the first time, a direct link between historical snow avalanches and dropstones preserved in lake sediments. Although the lacustrine varve record does not allow for the development of a complete annual reconstruction of the snow avalanche history in the Kenai Lake valley, our results suggest that it can be used for long-term decadal reconstructions of the snow-avalanche history, ideally in combination with similar records from lakes elsewhere in the region.

Martin Finné, Sakari Salonen, Norbert Frank et al.

Continental records with absolute dates of the timing and progression of climatic conditions during the Last Interglacial (LIG) from northern Europe are rare. Speleothems from northern Europe have a large potential as archives for LIG environmental conditions since they were formed in sheltered environments and may be preserved beneath ice sheets. Here, we present δ¹³C and δ¹⁸O values from speleothem Kf-21, from Korallgrottan in Jämtland (northwest Sweden). Kf-21 is dated with five MC-ICPMS U-Th dates with errors smaller than ~1 ka. Kf-21 started forming at ~130.2 ka and the main growth phase with relatively constant growth rates lasted from 127.3 ka to 124.4 ka, after which calcite formation ceased. Both δ¹³C and δ¹⁸O show rapid shifts but also trends, with a range of values within their Holocene counterparts from Korallgrottan. Our results indicate an early onset of the LIG in northern Europe with ice-free conditions at ~130 ka. Higher growth rates combined with more negative δ¹⁸O values between ~127.3 and 126.8 ka, interpreted here as warmer and more humid conditions, as well as indications of a millennial-scale cold spell centered at 126.2 ka, resemble findings from speleothem records from other parts of Europe, highlighting that these were regional scale climatic patterns.

Thierry Batard

In glaring contrast to its indisputable century-old experimental success, the ultimate objects and meaning of quantum physics remain a matter of vigorous debate among physicists and philosophers of science. This article attempts to shed new light on the debate. It relies upon two comments by Albert Einstein on his general approach to physical theories. I draw their consequences for the definition of a physical theory's ontology, and next for the ontology of quantum physics - i.e. what it may ultimately be about. The quantum ontology thus derived appears to be strictly limited to evolving experimental contexts and instantaneous measurement outcomes, which are to be understood, respectively, as mere potential measurement outcomes and actual ones. The notions of material body in particular and physical system in general are absent from this ontology, hence the vanishing of Schroedinger's cat and EPR paradoxes, as well as of the quantum measurement problem. Apart from its ability to clear up well-known conundrums, this ontology reveals what quantum physics may fundamentally be - i.e. its possible ultimate meaning - namely a theory of general relativity of experimental context. On this basis, I conclude with a new conception of objectivity in the sciences of nature.