1,481 research outputs found

    "Righteous Yang”: Pirate, Rebel, and Hero on the Sino-Vietnamese Water Frontier, 1644-1684

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    This article is a case study of a little-known but important historical figure, known variously as Yang Yandi (DÆ°ÆĄng NgáșĄn Địch), Yang Er, and, more colloquially, “Righteous Yang” (Yang Yi), who lived during the turbulent Ming-Qing transition (1644–1684). In that age of anarchy, it was easy for charismatic individuals like Yang to possess multiple identities and affiliations—in Yang’s case, pirate, rebel, and hero. Based on written historical documents and historical fieldwork, this article traces Yang’s life in the chaotic water frontier of the Gulf of Tonkin and argues that he was but one in a long line of pirates and dissidents who operated in this region. Keywords: Yang Yandi, DÆ°ÆĄng NgáșĄn Địch, Gulf of Tonkin, water frontier, piracy, Vietnam, South Chin

    HIV/AIDS and Agrarian Livelihoods in Zambia: a Test of the New Variant Famine Hypothesis.

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    1. Consistent with the New Variant Famine (NVF) hypothesis, the negative impact of drought on crop output and output per hectare is further exacerbated where HIV prevalence rates are relatively high, particularly in the low- and medium rainfall zones of the country (agro-ecological regions I and II). 2. HIV prevalence rates and AIDS-related mortality rates in Zambia are highest in the lowest rainfall and most drought-prone zone of the country (agro-ecological region I). 3. Only for districts in agro-ecological region I do we find evidence of a robust negative effect of HIV/AIDS on agrarian livelihood indicators. Relatively stable food production zones and/or areas with relatively low HIV prevalence rates appear to be less vulnerable to the adverse effects predicted by the NVF hypothesis, which suggests that HIV/AIDS exacerbates the effects of drought and other shocks on agrarian communities. 4. HIV/AIDS reduces the crop production gains associated with fertilizer subsidy increases in the highest rainfall areas. 5. Increases in the percentage of female-headed households in a district are related to declines in agricultural production indicators, but these effects do not appear to worsen when the HIV/AIDS epidemic is severe. 6. Only in districts whose borders encompass both agro-ecological regions II and III do we consistently find weak evidence that HIV/AIDS reduces the contribution of productive assets to crop output and output per unit of land as would be expected under the NVF hypothesis.food security, food policy, Zambia, HIV/AIDS, Food Security and Poverty, Health Economics and Policy, Q20,

    A major role for protein kinase C in calcium-activated exocytosis in permeabilised adrenal chromaffin cells

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    AbstractThe role of endogenously activated protein kinase C in calcium-activated exocytosis was examined in digitonin-permeabilised bovine adrenal chromaffin cells. Protein kinase C activity was reduced by down-regulation following long-term treatment with PMA or by using the inhibitor sphingosine. Both treatments resulted in a substantial reduction in catecholamine secretion elicited by micromolar calcium, indicating that endogenous activation of protein kinase C is a major requirement for calcium-activated exocytosis in chromaffin cells

    The dynamic Arctic

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    Research campaigns over the last decade have yielded a growing stream of data that highlight the dynamic nature of Arctic cryosphere and climate change over a range of time scales. As a consequence, rather than seeing the Arctic as a near static environment in which large scale changes occur slowly, we now view the Arctic as a system that is typified by frequent, large and abrupt changes. The traditional focus on end members in the system - glacial versus interglacial periods - has been replaced by a new interest in understanding the patterns and causes of such dynamic change. Instead of interpreting changes almost exclusively as near linear responses to external forcing (e.g. orbitally-forced climate change), research is now concentrated on the importance of strong feedback mechanisms that in our palaeo-archives often border on chaotic behaviour. The last decade of research has revealed the importance of on-off switching of ice streams, strong feedbacks between sea level and ice sheets, spatial and temporal changes in ice shelves and perennial sea ice, as well as alterations in ice sheet dynamics caused by shifting centres of mass in multi-dome ice sheets. Recent advances in dating techniques and modelling have improved our understanding of leads and lags that exist in different Arctic systems, on their interactions and the driving mechanisms of change. Future Arctic research challenges include further emphases on rapid transitions and untangling the feedback mechanisms as well as the time scales they operate on

    Complexity Equals Anything II

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    We expand on our results in arXiv:2111.02429 to present a broad new class of gravitational observables in asymptotically Anti-de Sitter space living on general codimension-zero regions of the bulk spacetime. By taking distinct limits, these observables can reduce to well-studied holographic complexity proposals, e.g., the volume of the maximal slice and the action or spacetime volume of the Wheeler-DeWitt patch. As with the codimension-one family found in arXiv:2111.02429, these new observables display two key universal features for the thermofield double state: they grow linearly in time at late times and reproduce the switchback effect. Hence we argue that any member of this new class of observables is an equally viable candidate as a gravitational dual of complexity. Moreover, using the Peierls construction, we show that variations of the codimension-zero and codimension-one observables are encoded in the gravitational symplectic form on the semi-classical phase-space, which can then be mapped to the CFT.Comment: 53 pages + 6 appendice

    Force transmission in a packing of pentagonal particles

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    We perform a detailed analysis of the contact force network in a dense confined packing of pentagonal particles simulated by means of the contact dynamics method. The effect of particle shape is evidenced by comparing the data from pentagon packing and from a packing with identical characteristics except for the circular shape of the particles. A counterintuitive finding of this work is that, under steady shearing, the pentagon packing develops a lower structural anisotropy than the disk packing. We show that this weakness is compensated by a higher force anisotropy, leading to enhanced shear strength of the pentagon packing. We revisit "strong" and "weak" force networks in the pentagon packing, but our simulation data provide also evidence for a large class of "very weak" forces carried mainly by vertex-to-edge contacts. The strong force chains are mostly composed of edge-to-edge contacts with a marked zig-zag aspect and a decreasing exponential probability distribution as in a disk packing

    Amphiphilic drug interactions with model cellular membranes are influenced by lipid chain-melting temperature.

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    Small-molecule amphiphilic species such as many drug molecules frequently exhibit low-to-negligible aqueous solubility, and generally have no identified transport proteins assisting their distribution, yet are able to rapidly penetrate significant distances into patient tissue and even cross the blood-brain barrier. Previous work has identified a mechanism of translocation driven by acid-catalysed lipid hydrolysis of biological membranes, a process which is catalysed by the presence of cationic amphiphilic drug molecules. In this study, the interactions of raclopride, a model amphiphilic drug, were investigated with mixtures of biologically relevant lipids across a range of compositions, revealing the influence of the chain-melting temperature of the lipids upon the rate of acyl hydrolysis

    Exogenous glucagon-like peptide-1 attenuates the glycaemic response to postpyloric nutrient infusion in critically ill patients with type-2 diabetes

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    Extent: 11p.Introduction: Glucagon-like peptide-1 (GLP-1) attenuates the glycaemic response to small intestinal nutrient infusion in stress-induced hyperglycaemia and reduces fasting glucose concentrations in critically ill patients with type-2 diabetes. The objective of this study was to evaluate the effects of acute administration of GLP-1 on the glycaemic response to small intestinal nutrient infusion in critically ill patients with pre-existing type-2 diabetes. Methods: Eleven critically ill mechanically-ventilated patients with known type-2 diabetes received intravenous infusions of GLP-1 (1.2 pmol/kg/minute) and placebo from t = 0 to 270 minutes on separate days in randomised double-blind fashion. Between t = 30 to 270 minutes a liquid nutrient was infused intraduodenally at a rate of 1 kcal/min via a naso-enteric catheter. Blood glucose, serum insulin and C-peptide, and plasma glucagon were measured. Data are mean ± SEM. Results: GLP-1 attenuated the overall glycaemic response to nutrient (blood glucose AUC30-270 min: GLP-1 2,244 ± 184 vs. placebo 2,679 ± 233 mmol/l/minute; P = 0.02). Blood glucose was maintained at < 10 mmol/l in 6/11 patients when receiving GLP-1 and 4/11 with placebo. GLP-1 increased serum insulin at 270 minutes (GLP-1: 23.4 ± 6.7 vs. placebo: 16.4 ± 5.5 mU/l; P < 0.05), but had no effect on the change in plasma glucagon. Conclusions: Exogenous GLP-1 in a dose of 1.2 pmol/kg/minute attenuates the glycaemic response to small intestinal nutrient in critically ill patients with type-2 diabetes. Given the modest magnitude of the reduction in glycaemia the effects of GLP-1 at higher doses and/or when administered in combination with insulin, warrant evaluation in this group.Adam M Deane, Matthew J Summers, Antony V Zaknic, Marianne J Chapman, Robert JL Fraser, Anna E Di Bartolomeo, Judith M Wishart, Michael Horowit
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