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101.
Having been adopted by legislatures in over a dozen states, postsecondary merit aid programs are largely concentrated in the southeastern United States. The observed clustering pattern seems to support previous evidence that policies spread between proximate states, a phenomenon referred to by political scientists as policy diffusion. Often, however, policy diffusion is not complete, and one or more states in a region fail to adopt. By interviewing policymakers throughout the southeastern United States—including actors in the three states in the region without merit aid—the study addresses the following question: Why do diffusion pressures lead to adoption in some states but not in others? Studying state “hold‐outs” promises not only to uncover the reasons for failed legislation in specific state contexts but also to better our understanding of the limits of diffusion theory. 相似文献
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L. Martin‐Francs M. Martinon‐Torres A. Gracia‐Tllez J. M. Bermúdez de Castro 《International Journal of Osteoarchaeology》2015,25(4):564-573
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
108.
M. Ma G. Dong X. Liu E. Lightfoot F. Chen H. Wang H. Li M. K. Jones 《International Journal of Osteoarchaeology》2015,25(6):923-934
Intercontinental exchanges between communities living in different parts of Eurasia during the late prehistoric period have become increasingly popular as a topic of archaeological research. The Qijia culture, found in northwest China, is one of the key archaeological cultures that can shed light on trans‐Eurasian exchange because a variety of imports are found in this cultural context. These imports include new cereals and animals, which suggest that human diets may also have changed compared with previous periods. To understand human and animal diets of the Qijia culture, carbon and nitrogen isotope ratios from human and animal skeletal remains were analysed from the type site of the Qijia culture at Qijiaping. The results demonstrate that human diet at the site mainly consisted of millet and animals fed on millet. C3 cereals, such as wheat and barley, did not contribute significantly to human diet, and no isotopic differences were found between adult and subadult diets. Furthermore, three outlying human results raise the possibility of exogenous individuals, perhaps in relation to the parallel movement of animals, crops and goods. This study provides human and animal dietary information for evaluating the nature of exchange and diffusion in eastern Eurasia at this time. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
109.
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
110.
Colgi, Cajal and the Neuron Doctrine 总被引:1,自引:0,他引:1
Jones EG 《Journal of the history of the neurosciences》1999,8(2):170-178
Camillo Golgi and Santiago Ramon y Cajal shared the Nobel Prize in 1906 for their work on the histology of the nerve cell, but both held diametrically opposed views about the Neuron Doctrine which emphasizes the structural, functional and developmental singularity of the nerve cell. Golgi's reticularist views remained entrenched and his work on the nervous system did not venture greatly into new territories after its original flowering, which had greater impact than is now commonly credited. Cajal, by contrast, by the time he was awarded the Nobel Prize, was already breaking new ground with a new staining technique in the field of peripheral nerve regeneration, seeing the reconstruction of a severed nerve by sprouting from the proximal stump as another manifestation of the Neuron Doctrine. Paradoxically, identical studies were going on simultaneously in Golgi's laboratory in the hands of Aldo Perroncito, but the findings did not seem to influence Golgi's thinking on the Neuron Doctrine. 相似文献