866 research outputs found

    Killing for Trophies: An Analysis of Global Trophy Hunting Trade

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    As the trophy hunting industry has grown over the last few decades, governments, conservationists, and animal welfare advocates are keen to understand its global economic and conservation impacts with data as supporting evidence. Unfortunately, little credible research had been done to understand the global trophy industry's extent and impact..This report is a result of a comprehensive analysis of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Trade Database. This analysis can serve as a baseline for more study on how trophy hunting is changing and how the global industry ultimately affects animals and their populations, both regionally and globally

    Decision-making by children

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    In this paper, we examine the determinants of decision-making power by children and young adolescents. Moving beyond previous economic models that treat children as goods consumed by adults rather than agents, we develop a noncooperative model of parental control of child behavior and child resistance. Using child reports of decision-making and psychological and cognitive measures from the NLSY79 Child Supplement, we examine the determinants of shared and sole decision-making in seven domains of child activity. We find that the determinants of sole decision-making by the child and shared decision-making with parents are quite distinct: sharing decisions appears to be a form of parental investment in child development rather than a simple stage in the transfer of authority. In addition, we find that indicators of child capability and preferences affect reports of decision-making authority in ways that suggest child demand for autonomy as well as parental discretion in determining these outcomes

    Three-dimensional photolithographic micropatterning: a novel tool to probe the complexities of cell migration

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    In order to independently study the numerous variables that influence cell movement, it will be necessary to employ novel tools and materials that allow for exquisite control of the cellular microenvironment. In this work, we have applied advanced 3D micropatterning technology, known as two-photon laser scanning lithography (TP-LSL), to poly(ethylene glycol) (PEG) hydrogels modified with bioactive peptides in order to fabricate precisely designed microenvironments to guide and quantitatively investigate cell migration. Specifically, TP-LSL was used to fabricate cell adhesive PEGRGDS micropatterns on the surface of non-degradable PEG-based hydrogels (2D) and in the interior of proteolytically degradable PEG-based hydrogels (3D). HT1080 cell migration was guided down these adhesive micropatterns in both 2D and 3D, as observed via time-lapse microscopy. Differences in cell speed, cell persistence, and cell shape were observed based on variation of adhesive ligand, hydrogel composition, and patterned area for both 2D and 3D migration. Results indicated that HT1080s migrate faster and with lower persistence on 2D surfaces, while HT1080s migrating in 3D were smaller and more elongated. Further, cell migration was shown to have a biphasic dependence on PEG-RGDS concentration and cells moving within PEG-RGDS micropatterns were seen to move faster and with more persistence over time. Importantly, the work presented here begins to elucidate the multiple complex factors involved in cell migration, with typical confounding factors being independently controlled. The development of this unique platform will allow researchers to probe how cells behave within increasingly complex 3D microenvironments that begin to mimic specifically chosen aspects of the in vivo landscape

    Reforming rural education : understanding teacher expectations for rural youth

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    The Chinese state\u27s commitment to improve teaching quality in rural regions is a key component of national efforts to close the rural–urban education gap. In this paper, we investigate an understudied but critical dimension of quality teaching: teacher expectations. We employ longitudinal data gathered in Gansu Province in 2000 and 2007 to first examine whether teacher expectations for rural youth are conditioned by students’ social origin and teacher background characteristics. Next, we determine the predictive accuracy of their expectations. Our results highlight the ways in which teacher expectations condition the sorting of rural children among different schooling tracks with distinct life trajectories. Significantly, teachers are more likely to hold lower expectations for students from disadvantaged backgrounds. In addition, non-local teachers hold lower expectations for rural children compared to local teachers. Finally, a low percentage of teachers expect students to enroll in post-compulsory vocational education. We consider the implications of these results for both educational policy and social inequality

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
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