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1.
The findings of psychiatrists working for the USAAF have long dominated scholarship on aerial combat stress during the Second World War, including explanations why the emotional casualty rate aboard American heavy bombers varied by crew position. Critical examination suggests that the answers put forward are unsatisfactory, opening the way for an alternate analytic approach. Comprehending the different forms and levels of sensory stress heavy bomber crews experienced during combat missions in combination with different degrees of individual agency yields a more nuanced and convincing way of comprehending why some jobs were more psychologically demanding than others, and hence why casualty rates varied.  相似文献   
2.
Accurate simulation of multiphase flow in fractured porous media remains a challenge. An important problem is the representation of the discontinuous or near discontinuous behaviour of saturation in real geological formations. In the classical continuum approach, a refined mesh is required at the interface between fracture and porous media to capture the steep gradients in saturation and saturation‐dependent transport properties. This dramatically increases the computational load when large numbers of fractures are present in the numerical model. A discontinuous finite element method is reported here to model flow in fractured porous media. The governing multiphase porous media flow equations are solved in the adaptive mesh computational fluid dynamics code IC‐FERST on unstructured meshes. The method is based on a mixed control volume – discontinuous finite element formulation. This is combined with the PN+1DG‐PNDG element pair, which has discontinuous (order N+1) representation for velocity and discontinuous (order N) representation for pressure. A number of test cases are used to evaluate the method's ability to model fracture flow. The first is used to verify the performance of the element pair on structured and unstructured meshes of different resolution. Multiphase flow is then modelled in a range of idealised and simple fracture patterns. Solutions with sharp saturation fronts and computational economy in terms of mesh size are illustrated.  相似文献   
3.
Environmental perturbations and social unrest are thought to have led to the reconstitution of traditional belief systems and hierarchical political relations on Peru’s North Coast during the Late Moche Period (550–800 AD). Ideological transformations are thus commonly interpreted as adaptive or reactive responses to social, political, and ecological disruptions. Nevertheless, religious practices directly shaped the formation of alternative power structures and ecological systems on the North Coast during the Late Moche Period. This is especially evident in Late Moche Jequetepeque, which witnessed the proliferation of non-elite ceremonial sites and small-scale agricultural facilities throughout the rural hinterland of the valley. Moche-inspired ritual performances orchestrated in the countryside created distinctive new forms of political order which structured economic activities and ecological behavior. In this article, the Jequetepeque case study is mobilized to reassess normative interpretations of the role of religious ideology in cultural adaptation and sociopolitical realignment.  相似文献   
4.
冯彩莉 《攀登》2007,26(6):176-178
文章在对青海省高校教师的职业压力进行调查的基础上,分析了这个群体的基本状况及他们所面临的问题,并提出缓解青海省高校中青年教师职业压力的建议。  相似文献   
5.
We present the palaeopathological analysis of a right fourth metatarsal (ATD6‐124) recovered from the Atapuerca–Gran Dolina site (Spain). This fossil, ca. 1 Ma, belongs to Homo antecessor, the earliest known European hominin species. The metatarsal exhibits a proliferative lesion on its medial periosteal surface. Periosteal reaction can be the bone response to a wide number of injurious processes. We describe a lesion on the basis of macroscopic and microscopic analyses, including microtomography and scanning electron microscopy. Externally, the osteoblastic lesion presents a highly porotic and disorganised morphology. Internally, we observe a series of micro‐fractures on the compact bone that do not affect the medullary canal. We provide a differential diagnosis and suggest that the ATD6‐124 lesion could correspond to a pedal stress fracture, also known as fatigue or march fracture. Stress fractures have been related to a load increase and muscular fatigue. This type of fracture has been widely reported in the foot of soldiers and athletes, which are usually engaged in strenuous, excessive or prolonged locomotive activities. Despite its high frequency in these groups, stress fractures have not been reported as such in fossil collections, with the exception of a metatarsal belonging to the Sima de los Huesos site (Atapuerca). Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
6.
In 1957, a new discovery inside Temple XVIII‐A was made in Palenque, the Mayan archaeological site in Chiapas Mexico, a royal tomb of an original design which proved to be the oldest at the site. Two skeletons were found, the principal (PAL‐44) was at the centre showing red pigmentation on the surface of some bones, personal adornments and offerings, which indicate that he was an early ruler of Palenque. The second (PAL‐45), deposited at the entrance, not in a special mortuary position, without offerings, suggests it was of a lower social status. This research presents a new bioarchaeological analysis with the following results: (i) The result of a direct radiocarbon dating of PAL‐44 by accelerator mass spectrometry is 250–420 cal AD (LTL12759A:1696 ± 30 BP). This means that the personage was buried long before the first designated ruler of Palenque, who, according to the epigraphic record was enthroned in ad 431. (ii) With X‐Ray Fluorescence, the red pigment was identified as cinnabar (HgS). (iii) PAL‐44 is a young adult male with a severe idiopathic scoliosis with a double curvature that affected the ribcage and lower limbs. Such a three‐dimensional deformity resulted in changes to his body mechanics and induced motion asymmetry. Consequently, his health and mobility must have been significantly affected by such a severe condition. (iv) PAL‐45 is an adult female with signs of nutritional problems in childhood and entheseal changes probably related to her activity. Three ante‐mortem traumas are registered: rib fracture, frontal depressed circular fracture and a nasal septal deviation. This traumatic event took place two weeks, approximately, prior to PAL‐45's death. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
7.
Legalized trauma     
In the past, criminals were executed by a variety of means, including beheading or hanging, and both these methods may leave signs on the skeleton. It is not difficult to recognize individuals who have been beheaded because one or other of the cervical vertebrae will show evidence of the fatal blow, and there may also be cut marks on the base of the skull or the back of the mandible. Death from hanging, however, often leaves no marks on the skeleton, especially when carried out with a running noose and no drop. With a drop, dislocation of the sutures at the base of the skull may be noted and the classic ‘hangman's fracture’, which is a fracture dislocation of the second cervical vertebra, may be present. When there is no evidence of trauma, death from hanging may have to be inferred in skeletons which are found with the hands tied or with other signs that are discussed here.  相似文献   
8.
This paper presents some of the basic principles of bone fracture physics and outlines characteristics used by forensic anthropologists to distinguish gunshot trauma from blunt trauma. The fracture pattern of a cranium from a historic cemetery in Memphis, Tennessee provides an example of how the mechanism of trauma could be misinterpreted. The pattern of the perimortem fractures is indicative of gunshot trauma with a bullet entering one side of the vault and impacting the opposite side. Identification of radiating fractures, concentric heaving fractures, and observation of the direction of bevel on the fractured surfaces are essential for interpretation of the mechanism that produced the injury.  相似文献   
9.
The biocultural effects of European contact varied considerably throughout the Americas. Some populations were decimated by colonialism, while others benefited from trade relationships and access to new technologies. It has been suggested that initial contact with European fur traders and explorers was economically favourable for Plains village populations, thereby facilitating a period of cultural florescence. In this study, we evaluate the hypothesis that Plains groups were better off than their predecessors during the initial contact period by comparing frequencies of enamel hypoplasia, cribra orbitalia, and porotic hyperostosis in pre‐ and post‐contact Arikara skeletal assemblages. We included both juveniles and adults in our sample to capture variation in the stress experience of different segments of the population. Our analysis revealed similarly low frequencies of cribra orbitalia in the pre‐ and post‐contact groups and no observed cases of porotic hyperostosis. Enamel hypoplasia, however, was significantly more prevalent among post‐contact Arikara villagers when compared to their pre‐contact counterparts, which suggests that stress levels were higher after European contact. Additionally, enamel hypoplasia was most common among post‐contact juveniles. The elevated frequency of enamel hypoplasia in the post‐contact sample combined with the low frequencies of cribra orbitalia and porotic hyperostosis suggests that disease stress, rather than nutritional deficiencies, was likely responsible for the decline in overall health following European contact. These results also suggest that juveniles are sensitive indicators of systemic stress within a population and should be included in bioarchaeological analyses of prehistoric health when available. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
10.
This paper presents a revised version of the Coimbra method for recording fibrocartilaginous entheses. The method itself is the only biologically appropriate recording method for fibrocartilaginous entheses that scores features separately, thereby ensuring that the aetiology of individual features can be studied. The method divides the enthesis into two zones, scoring the relevant features in each zone. These features represent either bone formation or bone destruction and include erosive lesions, fine and macro‐porosity, and cavitations. The revised method includes a new feature, textural change, which is scored as absent or present when it involves 50% or more of the surface. All other features are now scored as zero (absent), one or two with the higher score representing greater expression of the feature. This change in scoring has led to the reduction of inter‐observer error with approximately 80% agreement for overall feature scores for both the common extensor origin and subscapularis insertion. The simplification of the scores and the reduction in inter‐observer error mean that the method is now recommended for widespread use. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
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