1,584 research outputs found

    Pheochromocytomas

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    Pheochromocytomas are rare catecholamine-secreting neuroendocrine tumors derived from chromaffin tissue of the adrenal medulla. Such tumors arising from the sympathetic ganglia of the thorax, abdomen, or pelvis are termed “paragangliomas” or “extra-adrenal pheochromocytomas.” The classic symptoms of these tumors are due to excess circulating levels of norepinephrine, epinephrine, or dopamine. Although 21% may be asymptomatic, the most common symptoms associated with pheochromocytomas include sweating, palpitations, and headaches in association with intermittent hypertension. If left untreated, excess catecholamines may result in hypertensive crisis leading to cardiac complications, cerebrovascular stroke, or ultimately sudden death. These catecholamine-secreting tumors are most commonly sporadic, but about 30% of patients have this disease as part of a familial disorder such as multiple endocrine neoplasia type 2 (MEN2) or von Hippel-Lindau (VHL) syndrome. Although most are benign, accurate recognition of pheochromocytomas with malignant potential and distant metastases remains a major diagnostic challenge. Advances in the field of molecular genetics have led to novel diagnostic and therapeutic strategies in an attempt to address this dilemma. Surgical excision of pheochromocytomas and paragangliomas is the mainstay of treatment and offers the only potential for cure. This chapter focuses on recent developments in the diagnosis of pheochromocytomas, encompassing biochemical, radiologic, histologic, and molecular analyzes. In addition, novel therapeutic strategies and advances in individualized targeted therapies for malignant pheochromocytomas will be discussed

    Taxing the Informal Economy: The Current State of Knowledge and Agendas for Future Research

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    This paper reviews the literature on taxation of the informal economy, taking stock of key debates and drawing attention to recent innovations. Conventionally, the debate on whether to tax has frequently focused on the limited revenue potential, high cost of collection, and potentially adverse impact on small firms. Recent arguments have increasingly emphasised the more indirect benefits of informal taxation in relation to economic growth, broader tax compliance, and governance. More research is needed, we argue, into the relevant costs and benefits for all, including quasi-voluntary compliance, political and administrative incentives for reform, and citizen-state bargaining over taxation

    Directly imaging spin polarons in a kinetically frustrated Hubbard system

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    The emergence of quasiparticles in quantum many-body systems underlies the rich phenomenology in many strongly interacting materials. In the context of doped Mott insulators, magnetic polarons are quasiparticles that usually arise from an interplay between the kinetic energy of doped charge carriers and superexchange spin interactions. However, in kinetically frustrated lattices, itinerant spin polarons - bound states of a dopant and a spin-flip - have been theoretically predicted even in the absence of superexchange coupling. Despite their important role in the theory of kinetic magnetism, a microscopic observation of these polarons is lacking. Here we directly image itinerant spin polarons in a triangular lattice Hubbard system realised with ultracold atoms, revealing enhanced antiferromagnetic correlations in the local environment of a hole dopant. In contrast, around a charge dopant, we find ferromagnetic correlations, a manifestation of the elusive Nagaoka effect. We study the evolution of these correlations with interactions and doping, and use higher-order correlation functions to further elucidate the relative contributions of superexchange and kinetic mechanisms. The robustness of itinerant spin polarons at high temperature paves the way for exploring potential mechanisms for hole pairing and superconductivity in frustrated systems. Furthermore, our work provides microscopic insights into related phenomena in triangular lattice moir\'{e} materials.Comment: 7 pages (4 figures) + 6 pages methods (7 figures

    Measuring Information Transfer

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    An information theoretic measure is derived that quantifies the statistical coherence between systems evolving in time. The standard time delayed mutual information fails to distinguish information that is actually exchanged from shared information due to common history and input signals. In our new approach, these influences are excluded by appropriate conditioning of transition probabilities. The resulting transfer entropy is able to distinguish driving and responding elements and to detect asymmetry in the coupling of subsystems.Comment: 4 pages, 4 Figures, Revte

    Fantasies of subjugation: a discourse theoretical account of British policy on the European Union

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    The decision by the UK government to hold a referendum on Britain’s membership of the European Union (EU) marks an important development in policy towards the EU. Policy changes of this kind must be understood in the historical and political context in which they occur. This includes the framing of the policy issues within public discourse. In the UK, policies are formed in a discursive environment which is overwhelmingly hostile towards the EU. Debates are structured by a predominantly Euroskeptic discourse which emphasizes the UK’s separation and heterogeneity from the rest of the EU. Drawing on the logics of critical explanation, this article examines the structure and affective power of Euroskeptic discourses which dictate the terms of the EU debate. It presents a case study of the recent EU treaty revision process, culminating in the Treaty of Lisbon. In so doing, it enables a deeper understanding of recent policy developments

    Test your surrogate data before you test for nonlinearity

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    The schemes for the generation of surrogate data in order to test the null hypothesis of linear stochastic process undergoing nonlinear static transform are investigated as to their consistency in representing the null hypothesis. In particular, we pinpoint some important caveats of the prominent algorithm of amplitude adjusted Fourier transform surrogates (AAFT) and compare it to the iterated AAFT (IAAFT), which is more consistent in representing the null hypothesis. It turns out that in many applications with real data the inferences of nonlinearity after marginal rejection of the null hypothesis were premature and have to be re-investigated taken into account the inaccuracies in the AAFT algorithm, mainly concerning the mismatching of the linear correlations. In order to deal with such inaccuracies we propose the use of linear together with nonlinear polynomials as discriminating statistics. The application of this setup to some well-known real data sets cautions against the use of the AAFT algorithm.Comment: 14 pages, 15 figures, submitted to Physical Review

    Distribution and Movements of the Teshekpuk Caribou Herd 1990–2005: Prior to Oil and Gas Development

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    Four caribou (Rangifer tarandus grantii) herds calve on the North Slope of Alaska, three of which have been exposed to little or no resource development. We present 15 years of baseline data on the distribution and movements of 72 satellite-collared and 10 GPS-collared caribou from the Teshekpuk caribou herd (TCH) that have had little to no exposure to oil and gas activities. Fixed-kernel home range analyses of collared caribou revealed that calving grounds were concentrated (i.e., 50% kernel utilization distribution) along the northeastern, eastern, and southeastern shores of Teshekpuk Lake. During the postcalving period, 51% and 35% of caribou moved through two constricted zones to the east and west of Teshekpuk Lake, respectively, and accessed insect-relief habitat along the Beaufort Sea coast. During late summer and early fall, TCH caribou were concentrated to the southeast and southwest of Teshekpuk Lake. Although 65% of the Teshekpuk caribou wintered in two areas on the central coastal plain around the village of Atqasuk and south of Teshekpuk Lake, other TCH animals wintered in a great variety of places, including the Seward Peninsula, the eastern and southern Brooks Range, and the Arctic National Wildlife Refuge. We detected an apparent emigration rate of 6.9%. One male and five female TCH caribou joined the breeding populations of the Western Arctic and Central Arctic herds. TCH caribou traveled an average distance of 2348 ± 190 km annually. Movement rates were at a maximum in midsummer, lowest in winter, and intermediate during spring and fall migrations. Restrictions on oil and gas leasing and surface occupancy have been in place to protect calving, migratory corridors, and insect-relief habitat for the TCH, but these protections are likely to be removed. These data will provide a good baseline that can be used to compare predevelopment distribution and movement patterns of TCH caribou to distribution and movement patterns during and after petroleum development.Quatre hardes de caribous (Rangifer tarandus grantii) vĂȘlent sur la cĂŽte nord de l’Alaska, dont trois de ces hardes ont Ă©tĂ© exposĂ©es Ă  peu ou pas d’amĂ©nagement des ressources. Nous prĂ©sentons des donnĂ©es de base Ă©chelonnĂ©es sur 15 ans relativement Ă  la rĂ©partition et aux dĂ©placements de 72 caribous dotĂ©s d’un collier Ă©metteur par satellite et de 10 caribous munis d’un collier Ă©metteur GPS de la harde de caribous de Teshekpuk (HCT), caribous qui ont Ă©tĂ© peu ou pas du tout frottĂ©s aux activitĂ©s pĂ©troliĂšres et gaziĂšres. L’analyse du noyau fixe des domaines vitaux des caribous Ă  collier a rĂ©vĂ©lĂ© que les lieux de vĂȘlage Ă©taient concentrĂ©s (c’est-Ă -dire 50 % de la rĂ©partition de l’utilisation du noyau) le long des cĂŽtes nord-est, est et sud-est du lac Teshekpuk. AprĂšs la pĂ©riode de vĂȘlage, 51 pour cent et 35 pour cent des caribous se dĂ©plaçaient au sein de deux zones de constriction Ă  l’est et Ă  l’ouest du lac Teshekpuk, respectivement, et accĂ©daient un habitat oĂč se trouvait moins d’insectes sur la cĂŽte de la mer de Beaufort. Vers la fin de l’étĂ© et le dĂ©but de l’automne, les caribous de la HCT Ă©taient concentrĂ©s au sud-est et au sud-ouest du lac Teshekpuk. Bien que 65 pour cent des caribous de Teshekpuk passaient l’hiver dans deux rĂ©gions de la plaine cĂŽtiĂšre centrale autour du village d’Atqasuk et au sud du lac Teshekpuk, les autres bĂȘtes de la HCT passaient l’hiver dans divers endroits, dont la pĂ©ninsule de Seward, les versants est et sud des montagnes de Brooks et la RĂ©serve faunique nationale de l’Arctique. Nous avons dĂ©tectĂ© un taux d’émigration apparent de 6,9 pour cent. Un caribou mĂąle et cinq caribous femelles de la HCT ont rejoint les populations de reproduction des hardes de l’ouest et du centre de l’Arctique. En moyenne, le caribou de la HCT parcourait une distance de 2348 ± 190 km annuellement. Les taux de dĂ©placement Ă©taient Ă  leur point le plus Ă©levĂ© au milieu de l’étĂ©, tandis qu’ils Ă©taient Ă  leur niveau le plus bas l’hiver et Ă  un niveau intermĂ©diaire pendant les migrations du printemps et de l’automne. Il existe des restrictions en matiĂšre de location et d’occupation en surface pour le pĂ©trole et le gaz afin de protĂ©ger le vĂȘlage, les corridors de migration et les habitats Ă  faible taux d’insectes pour la HCT, mais il est vraisemblable que ces restrictions soient Ă©liminĂ©es. Ces donnĂ©es fourniront une bonne base pour comparer la rĂ©partition et les dĂ©placements du caribou de la HCT avant la mise en valeur des ressources Ă  la rĂ©partition et aux dĂ©placements du caribou de la HCT pendant et aprĂšs la mise en valeur pĂ©troliĂšre

    Are Clean Eating Blogs a Source of Healthy Recipes? A Comparative Study of the Nutrient Composition of Foods with and without Clean Eating Claims

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    © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Food blogs are an increasingly popular source of information about food and nutrition. There is a perception that foods published on clean eating blogs, which promote unprocessed foods, are healthier than comparable foods without these claims. However, foods with these claims and their nutrient composition have not previously been evaluated. The purpose of the study was to describe the nutritional content of clean eating recipes compared to recipes without clean eating claims and the nutritional guidelines published by the World Health Organisation (WHO). Clean eating recipes were systematically selected from 13 popular clean eating blogs and were described and compared with control recipes without clean eating claims. The nutrient profiles from the included recipes were summarised and evaluated against criteria from WHO recommendations for chronic disease prevention and criteria from the U.K. Food Standards Agency. Data for 86 clean eating recipes were extracted that represented five food categories: breakfast, snacks, treats, desserts, and smoothies. These were matched with 86 control recipes without clean eating claims. The clean eating recipes, per portion, provide the equivalent of 15% of daily energy intake. The average serving sizes were not significantly different between clean eating and control recipes. Overall, the clean eating recipes contained significantly more protein (8.1 ± 7.3 g vs. 5.7 ± 4.1 g, p = 0.01), fat (15.8 ± 10.6 g vs. 12.4 ± 9.3 g, p = 0.03), and fibre (5.0 ± 4.3 g vs. 2.8 ± 2.9 g, p < 0.01) per serving than control recipes. There were no significant differences between clean eating and control recipes with respect to the energy (1280 ± 714 kJ vs. 1137 ± 600 kJ, p = 0.16), carbohydrate (31.5 ± 27.3 g vs. 33.9 ± 19.4 g, p = 0.51), sugar (21.1 ± 20.9 g vs. 23.2 ± 14.9 g, p = 0.46), and sodium content (196.7 ± 269 vs. 155.8 ± 160.8, p = 0.23). Less than 10% of clean eating and control recipes met the WHO constraints for proportions of energy from fat and sugar intake. A simulated nutrient profile of an average clean and control recipe shows that nutrients for both are similarly classified as moderate to high in fat, saturated fat, salt, and sugar. Foods with clean eating claims contained the same amount of energy, sugar, and sodium as foods without those claims. Clean eating claims are potentially misleading for consumers who may believe these foods are healthy alternatives, potentially undermining people’s efforts to eat a healthy die

    Use of satellite telemetry to evaluate movements of caribou within subsistence hunting areas in northern Alaska

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    Caribou from the Teshekpuk Herd (TH) are an important subsistence resource for residents of Inupiaq villages in northern Alaska. In recent years the use of satellite telemetry has increased the understanding of the herd's annual movements and interactions with other herds. Most caribou of the TH are within the National Petroleum Reserve&mdash;Alaska (NPRA) throughout the year. The northeastern portion of NPRA has undergone two lease sales for oil and gas exploration, and lease sales are tentatively scheduled for the central/northwest portion of the NPRA in 2004. During 1990&mdash;1999, the movements of 27 caribou from the TH were tracked using satellite collars. We evaluated the proportion of time caribou were available to Inupiaq hunters by incorporating maps depicting subsistence-use areas for each of seven Inupiaq villages, and then examining seasonal and annual movements of caribou relative to those areas. By combining caribou locations with subsistence hunting areas, we were able to explore spatial and temporal patterns in caribou availability to subsistence hunters. This information is useful for managers to set appropriate hunting regulations and for devising sensible alternatives and mitigation of likely petroleum development in NPRA

    Use of satellite telemetry data, GIS, and HTML to create an interactive display of caribou movements

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    The use of animation clearly reveals the large annual variation in wintering areas and large differences in daily movement rates for this herd. This interactive display can be adapted for school groups, subsistence hunters, the general public, or scientists
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