267 research outputs found
The relationship between the fat content of Svalbard reindeer in autumn and their death from starvation in winter
The relationship between body fat reserves in autumn and age-specific mortality in winter were examined in Svalbard reindeer (Rangifer tarandus platyrhynchus Vrolik). Total dissectible fat (TDF) was measured in 17 females, 1-12 years of age, shot on Spitsbergen (78°N lat.) in autumn 1980-1981. TDF declined with age in reindeer 2 years and older. The youngest females which died in winter, with the exception of calves, were aged 7 years old. A direct causal link between low autumn TDF and mortality in winter seemed unlikely. Mortality was clearly associated with the degree of wear of molariform teeth. Perhaps severe tooth wear results in inefficient mastication of low quality forage and a decline in the rate of passage of digesta, thereby restricting the amount of food that reindeer can eat. A simple model of the energy balance of female Svalbard reindeer in winter shows that they must obtaine not less than about 74% of their total energy requirements from forage. Consequently, differences in the ability of individual reindeer to feed in winter are potentially more important for survival than differences in their fat content in autumn
Faeces is a reliable source of body water for measuring tritium in reindeer in summer and in winter
Rates of equilibration and subsequent wash-out of tritium were measured in parallel samples of blood, rumen fluid and faeces collected from two adult female Norwegian reindeer in summer and in winter. The tritium-concentration was the same in all three body water compartments after no more than 9 h following both intravenous and intra-ruminal injection of isotope in summer and following intravenous injection of isotope in winter. The biological half-life of the tritium increased from approximately 3 days in summer to approximately 10 days in winter, probably as a consequence of a decrease in water intake. There were no significant differences in disappearance rates of tritium from blood, rumen fluid and faeces within any of the six experiments. Fresh faeces is therefore a reliable source of body water that can be used in place of blood in studies of body water kinetics in reindeer, thus making it potentially possible to conduct such studies on truly free-living and undisturbed animals
Otolith evidence concerning interrelationships of caproid, zeiform and tetraodontiform fishes
Otolith features are used to test osteology-based hypotheses about interrelationships among caproid, zeiform and tetraodontiform fishes and intrarelationships of the taxa within each concerned group. Otolith morphology suggests that caproids are the plesiomorphic sister group of [zeiforms + tetraodontiforms]. In zeiforms, otolith data are in reasonable agreement with the homogeneity of the families defined upon osteology, but they are of little use in supporting interrelationships among these families. Problematic cases are the plesiomorphic otoliths of Parazen and Zenion, which would group these two taxa as a plesiomorphic sister group of all other zeiforms. The placement of Parazen as sister to [Cyttopsis + Stethopristes] in parazenids and Zenion as sister to [Capromimus + Cytomimus] in zeniontids, however, is logically consistent within both families. In tetraodontiforms. otoliths exhibit a broad range of very different morphologies, but there are no apparent contradictions with the osteology-based phylogenetic hypotheses. The main interest of otolith morphologies among tetraodontiforms is the evidencc that strongly supports the recognition of three clades within balistids, and the confirmation of tetraodontids and diodontids as, respectively, plesiomorphic and apomorphic sister groups
When is policing fair? Groups, identity and judgements of the procedural justice of coercive crowd policing
Procedural justice theory (PJT) is now a widely utilised theoretical perspective in policing research that acknowledges the centrality of police âfairnessâ. Despite its widespread acceptance this paper asserts that there are conceptual limitations that emerge when applying the theory to the policing of crowd events. This paper contends that this problem with PJT is a result of specific assumptions that are highlighted by two studies using a novel experimental approach. Study 1 systematically manipulated the social categories used to describe crowd participants subjected to police coercion. The experiment demonstrates how these social categories dramatically affected participantsâ perceptions of the same police action and that it was participantsâ relational identification with the police, rather than a superordinate category, that mediated the association between judgements of procedural fairness and intentions to cooperate. In Study 2, using a quasi-experimental design, we then replicated and extended these findings by demonstrating how perceptions of procedural fairness are also influenced by levels of in-group identification. The paper concludes by exploring the implications of the data for reconceptualising the social psychological processes mediating these judgements and impacts of police legitimacy
NONLINEAR EFFECTS OF CLIMATE AND DENSITY IN THE DYNAMICS OF A FLUCTUATING POPULATION OF REINDEER
Nonlinear and irregular population dynamics may arise as a result of phase dependence and coexistence of multiple attractors. Here we explore effects of climate and density in the dynamics of a highly fluctuating population of wild reindeer (Rangifer tarandus platyrhynchus) on Svalbard observed over a period of 29 years. Time series analyses revealed that density dependence and the effects of local climate (measured as the degree of ablation [melting] of snow during winter) on numbers were both highly nonlinear: direct negative density dependence was found when the population was growing (Rt . 0) and during phases of the North Atlantic Oscillation (NAO) characterized by winters with generally high (1979â 1995) and low (1996â2007) indices, respectively. A growth-phase-dependent model explained the dynamics of the population best and revealed the influence of density-independent processes on numbers that a linear autoregressive model missed altogether. In particular, the abundance of reindeer was enhanced by ablation during phases of growth (Rt . 0), an observation that contrasts with the view that periods of mild weather in winter are normally deleterious for reindeer owing to icing of the snowpack. Analyses of vital rates corroborated the nonlinearity described in the population time series and showed that both starvation mortality in winter and fecundity were nonlinearly related to fluctuations in density and the level of ablation. The erratic pattern of growth of the population of reindeer in Adventdalen seems, therefore, to result from a combination of the effects of nonlinear density dependence, strong density-dependent mortality, and variable density independence related to ablation in winter. Key words: Arctic; attractors; climate; density dependence; mortality; nonlinear population dynamics; North Atlantic Oscillation (NAO); phase dependence; phaseâspace geometry; Rangifer tarandus platyrhynchus; reindeer; Svalbard
Understanding the UK hospital supply chain in an era of patient choice
Author Posting © Westburn Publishers Ltd, 2011. This is a post-peer-review, pre-copy-edit version of an article which has been published in its definitive form in the Journal of Marketing Management, and has been posted by permission of Westburn Publishers Ltd for personal use, not for redistribution. The article was published in Journal of Marketing Management, 27(3-4), 401 - 423, doi:10.1080/0267257X.2011.547084 http://dx.doi.org/10.1080/0267257X.2011.547084The purpose of this paper is to investigate the UK hospital supply chain in light of recent government policy reform where patients will have, inter alia, greater choice of hospital for elective surgery. Subsequently, the hospital system should become far more competitive with supply chains having to react to these changes as patient demand becomes less predictable. Using a qualitative case study methodology, hospital managers are interviewed on a range of issues. Views on the development of the hospital supply chain in different phases are derived, and are used to develop a map of the current hospital chain. The findings show hospital managers anticipating some significant changes to the hospital supply chain and its workings as Patient Choice expands. The research also maps the various aspects of the hospital supply chain as it moves through different operational phases and highlights underlying challenges and complexities. The hospital supply chain, as discussed and mapped in this research, is original work given there are no examples in the literature that provide holistic representations of hospital activity. At the end, specific recommendations are provided that will be of interest to service to managers, researchers, and policymakers
High-Dimensional Menger-Type Curvatures-Part II: d-Separation and a Menagerie of Curvatures
This is the second of two papers wherein we estimate multiscale least squares
approximations of certain measures by Menger-type curvatures. More
specifically, we study an arbitrary d-regular measure on a real separable
Hilbert space. The main result of the paper bounds the least squares error of
approximation at any ball by an average of the discrete Menger-type curvature
over certain simplices in in the ball. A consequent result bounds the
Jones-type flatness by an integral of the discrete curvature over all
simplices. The preceding paper provided the opposite inequalities. Furthermore,
we demonstrate some other discrete curvatures for characterizing uniform
rectifiability and additional continuous curvatures for characterizing special
instances of the (p, q)-geometric property. We also show that a curvature
suggested by Leger (Annals of Math, 149(3), p. 831-869, 1999) does not fit
within our framework.Comment: 32 pages, no figure
Adsorption of Cd, Cu, Ni and Zn in tropical soils under competitive and non-competitive systems
The adsorption of heavy metals in soils affects their behavior in the environment and their bioavailability to plants. The knowledge of the adsorption mechanisms in competitive systems allows a more realistic evaluation of the metals' behavior in the soil than the single metal adsorption. The objectives of this study were (i) to evaluate Cd, Cu, Ni, and Zn adsorption in 14 surface samples (0-0.2 m) of representative soils of the Brazilian humid-tropical region, in competitive and non-competitive systems, and (ii) to establish metal affinity sequences for each soil, based in the maximum adsorption capacity (MAC) estimated by the Langmuir model. The Rhodic Eutrudox, the Kandiudalf Eutrudox, the Arenic Hapludalf, the Arenic Hapludult and the Typic Argiudoll had the highest metals' adsorption capacity, whereas the Typic Quartzipsamment and the sandy-textured Arenic Hapludult had the lowest values. In general, the MAC values for metals were lower in the competitive than in the non-competitive system. In the non-competitive system, the most common affinity sequence was Cu > Zn > Ni > Cd, whereas the most common sequence was Cu > Cd > Zn > Ni in the competitive system. In general, the Langmuir model fitted well the adsorption data of metals on the studied soils.A adsorção de metais pesados em solos afeta seu comportamento e biodisponibilidade Ă s plantas. O conhecimento dos mecanismos de adsorção em sistemas competitivos permite uma avaliação mais realista do comportamento dos metais no solo do que estudos com adsorção de cada metal, isoladamente. Os objetivos desse trabalho foram: (i) avaliar a adsorção de Cd, Cu, Ni e Zn em amostras superficiais (0-0,2 m) de 14 solos representativos da regiĂŁo tropical Ășmida, em sistema competitivo e nĂŁo-competitivo, e (ii) estabelecer sequĂȘncias de afinidade metĂĄlica para cada solo, com base nos valores de capacidade mĂĄxima de adsorção (CMA) dos metais estimados por meio do modelo de Langmuir. O Rhodic Eutrudox, o Kandiudalfic Eutrudox, o Arenic Hapludalf (Alf2), o Arenic Hapludult (Ult2) e o Typic Argiudoll apresentaram elevadas capacidades de adsorção dos metais, ocorrendo o inverso para o Typic Quartzipsamment e para o Arenic Hapludult textura arenosa. No geral, a CMA dos metais aos solos foi menor no sistema competitivo. A sequĂȘncia de afinidade mais comumente encontrada no sistema nĂŁo-competitivo foi Cu > Zn > Ni > Cd. No sistema competitivo, a sequĂȘncia foi Cu > Cd > Zn > Ni. Em geral, o modelo de Langmuir simulou de maneira satisfatĂłria a adsorção dos metais nas amostras de solo
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