943 research outputs found
Animal welfare and the harp seal hunt in Atlantic Canada
No full textMuch attention has been given over the years to animal welfare issues surrounding the seal hunt in Atlantic Canada. However, very little information is available on this subject in the scientific literature. This article reports the results of observations made by representatives of the Canadian Veterinary Medical Association at the hunt in recent years and compares them with observations made by members of the International Fund for Animal Welfare. The conclusion is that the large majority of seals taken during this hunt (at best, 98% in work reported here) are killed in an acceptably humane manner. However, the small proportion of animals that are not killed effectively justifies continued attention to this hunt on the part of the veterinary profession.LR: 20070221; PUBM: Print; JID: 0004653; ppublishSource type: Electronic(1
Conservação de esporos, germinação e desenvolvimento gametofítico de Pleopeltis lepidopteris: análises morfofisiológicas e ultraestruturais
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Biologia de Fungos, Algas e Plantas, Florianópolis, 2015.Pleopeltis lepidopteris (Langsd. & Fisch) de la Sota (Polypodiaceae) é uma samambaia endêmica importante da vegetação de restingas do sul do Brasil. A vegetação de restinga vem sofrendo fortes ameaças com o aumento da especulação imobiliária, ocupação humana, a poluição e a extração. Esporos de P. lepidopteris foram coletados em setembro de 2013 e março de 2014 nas Dunas da Praia da Joaquina, Florianópolis, SC, Brasil. Para preservar eficazmente esporos de P. lepidopteris foram avaliados os efeitos de diferentes tratamentos na viabilidade dos esporos e desenvolvimento gametofítico. Foi analisada a viabilidade de esporos recém coletados em setembro de 2013. Os esporos foram armazenados: por um e oito meses nas frondes à temperatura ambiente; sob-refrigeração 7±1ºC; imersos em nitrogênio líquido (-196ºC) não esterilizados e esterilizados superficialmente após degelo. Foram realizadas análises morfológicas de esporos e gametófitos por meio de microscopia de luz (ML), microscopia confocal de varredura a laser (MCVL), microscopia eletrônica de varredura (MEV) e microscopia eletrônica de transmissão (MET). Análises de conteúdo de pigmentos fotossintetizantes e fluorescência da clorofila a foram realizadas em gametófitos de 150 dias. Esporos de P. lepidopteris perdem rapidamente a viabilidade dentro de um mês e morrem após oito meses, quando armazenados à temperatura ambiente. Houve grande redução da viabilidade quando os esporos foram armazenados a 7±1ºC após oito meses. Em contraste, esporos sobreviveram e apresentaram as mais altas porcentagens de germinação quando armazenados em nitrogênio líquido indiferentemente da época de coleta. Esporos criopreservados analisados em MEV apresentaram a superfície e as ornamentações mais ásperas do que os esporos controles. A criopreservação aparentemente escarificou a superfície dos esporos. Houve aceleração e desenvolvimento normal de gametófitos oriundos de esporos criopreservados e surgimento antecipado de estruturas reprodutivas. Não houve diferença na ultraestrutura de esporos e gametófitos de ambos os tratamentos e nem nos conteúdos de pigmentos fotossintetizantes e nos parâmetros fotossintéticos obtidos a partir da análise da fluorescência da clorofila a. A criopreservação mostrou-se eficaz para a conservação ex situ em bancos de germoplasma de esporos de Pleopeltis lepidopteris, mantendo sua viabilidade e integridade fisiológica.Abstract : Pleopeltis lepidopteris (Langsd. & Fisch) de la Sota (Polypodiaceae) is an important endemic fern of the dunes vegetation of southern Brazil. The ?restinga? vegetation has been suffering strong threats with the human occupation, pollution and extraction. Spores of P. lepidopteris were collected in September 2013 and March 2014 in the dunes of Joaquina Beach, Florianópolis, SC, Brazil. To effectively preserve P. lepidopteris spores the effects of different treatments of conservation were analised. The viability of spores collected in September 2013 were analised and compared to different methods of conservation: spores stored for eight months in the fronds at room temperature, spores stored under refrigeration at 7±1ºC, spores immersed in liquid nitrogen (-196ºC) non-sterile or surface steriled after thaw. Morphological analysis of spores and gametophytes were performed by light microscopy (ML), confocal laser scanning microscopy (CLSM), scanning electronic microscopy (SEM) and transmission electronic microscopy (MET). Analisys of photosynthetic pigmens and fluorescence of chlorophyll a were performed in gametophytes of 150 days. Spores of P. lepidopteris rapidly lose viability within a month and die after eight months when stored at room temperature. There was a great reduction of viability when the spores were stored at 7±1ºC after eight months. In contrast, spores survived and presented the highest percentage of germination when stored in liquid nitrogen regardless the period of collection. The surface of the cryopreserved spores analyzed by SEM was rougher than that of controls. Cryopreservation apparently scarified spore surface. There was acceleration of development of gametophyte grown from criopreserved spores and early onset of reproductive structures. There were no differences in the ultrastructure of spores and gametophytes of both treatments or in the photosynthetic pigment content and the photosynthetic parameters obtained from the analysis of chlorophyll a fluorescence. Cryopreservation was effective for the ?ex situ? conservation in germplasm banks of spores of Pleopeltis lepidopteris spores, maintaining their viability and physiological integrity
Mechanics of inhomogeneous turbulence and interfacial layers
No full textThe mechanics of inhomogeneous turbulence in and adjacent to interfacial layers bounding turbulent and non-turbulent regions are analysed. Different mechanisms are identified according to the straining by the turbulent eddies in relation to the strength of the mean shear adjacent to, or across, the interfacial layer. How the turbulence is initiated and the topology of the region of turbulence are also significant factors. Specifically the cases of a layer of turbulence bounded on one, or two, sides by a uniform and/or shearing flow, and a circular region of a rotating turbulent vortex are considered and discussed.
The entrainment processes at fluctuating interfaces occur both at the outer edges of turbulent shear layers, with and without free-stream turbulence (e.g. jets, wakes and boundary layers), at internal boundaries such as those at the outside of the non-turbulent core of swirling flows (e.g. the ‘eye-wall’ of a hurricane) or at the top of the viscous sublayer and roughness elements in turbulent boundary layers. Conditionally sampled data enables these concepts to be tested. These concepts lead to physically based estimates for critical modelling parameters such as eddy viscosity near interfaces, entrainment rates, maximum velocity and displacement heights
The Canadian harp seal hunt: observations on the effectiveness of procedures to avoid poor animal welfare outcomes
No full textThe Canadian harp seal (Pagophilus groenlandicus) hunt has, for several decades, raised public concerns related to animal welfare. The field conditions under which this hunt is carried out do not lend themselves easily to detailed observations and analyses of its killing practices. This article reports observations carried out over several seasons that aimed at obtaining more specific information about the conditions under which seals are killed, in order to assess potential welfare issues and explore avenues for possible improvements in its practice. A standardised three-step process for killing seals (ie stunning, checking by palpation of the skull, and bleeding) was recently implemented to maximise the proportion of animals that are killed rapidly with minimum pain. Based on field observations, the rifle and the hakapik, when used properly, appeared to be efficient tools for stunning and/or killing young harp seals. All carcases of seals observed to be killed with a rifle, either on the ice or in the water, could be recovered. However, shooting seals in water rather than on ice carried a higher risk of poor welfare outcome because of the limited opportunities to shoot the animals again if not stunned with the first shot. Based on current practices, there is no reliable evidence that the Canadian harp seal hunt differs from other forms of exploitation of wildlife resources from the perspective of animal welfare. Although opportunistic field observations may be less amenable to generalisation than structured studies, we believe that they reflect the reality of the hunt and provide valuable information to direct the evolution of its practice.P.-Y. Daoust and C. Carague
CFD modelling of natural ventilation: combined wind and buoyancy forces
No full textThis paper builds on Cook’s PhD research and represents some of the work undertaken as part of his EPSRC First Grant, which was rated by referees as Tending to Internationally Leading for both its Research Quality and Scientific Impact. Other output related to this project is listed under Ji, who was the PhD student on that project.
Cook was the lead author of this paper and the co-author Hunt (Imperial) was responsible for the experimental work. Ji, now an ECR, undertook most of the simulation work. A precursor to this journal paper won the CIBSE National Conference 2004 Best Poster Prize
Conheça a Pesquisadora: Mary E. Hunt
No full textThis article presents the talk given by the author during the “Meet the Researcher” event, organized by the Research Group indecencies – Religion, Gender, and Sexuality (ReGeSex – PPCIR/UFJF). It offers reflections on: (1) how she came to Latin America and how that changed her life; (2) what WATER is and what it does; (3) some trends and developments in feminist studies in religion over the forty years of her work; and (4) what we can reasonably expect for the future. Narrating her journey in the first person and from her own experience, the author invites readers to reflect on important and profound questions related to the trajectory of feminist and queer theologies, the current context, and the challenges and possibilities ahead.Este artículo presenta la exposición realizada por la autora en la actividad “Conozca a la Investigadora”, promovida por el Grupo de Investigación indecencias – Religión, Género y Sexualidad (ReGeSex – PPCIR/UFJF). Ofrece reflexiones sobre: (1) cómo llegó a América Latina y cómo eso cambió su vida; (2) qué es WATER y qué hace; (3) algunas tendencias y desarrollos en los estudios feministas en religión a lo largo de cuarenta años de trabajo; y (4) qué podemos esperar razonablemente para el futuro. Narrando su trayectoria en primera persona y desde su propia experiencia, la autora invita a reflexionar sobre cuestiones importantes y profundas relacionadas con el recorrido de las teologías feministas y queer, el contexto actual y los desafíos y posibilidades que se presentan.Este artigo traz a apresentação feita pela autora na atividade “Conheça a Pesquisadora”, promovida pelo Grupo de Pesquisa indecências – Religião, Gênero e Sexualidade (ReGeSex – PPCIR/UFJF). Oferece reflexões sobre (1) como ela chegou à América Latina e como isso mudou sua vida; (2) WATER e o que faz; (3) algumas tendências e desenvolvimentos nos estudos feministas em religião ao longo dos quarenta anos desse trabalho; (4) o que nós podemos razoavelmente esperar no futuro. Narrando sua trajetória em primeira pessoa e desde a sua própria experiência, a autora convida a reflexões sobre questões importantes e profundas relacionadas à trajetória das teologias feministas e queer, o contexto atual e desafios e possibilidades para o futuro
The Structure of Optimal and Near Optimal Target Sets in Consensus Models
No full textWe consider the problem of identifying a subset of nodes in a network that will enable the fastest spread of information in a decentralized environment.In a model of communication based on a random walk on an undirected graph, the optimal set over all sets of the same or smaller cardinality minimizes the sum of the mean first arrival times to the set by walkers starting at nodes outside the set. The problem originates from the study of the spread of information or consensus in a network and was introduced in this form by V.Borkar et al. in 2010. More generally, the work of A. Clark et al. in 2012 showed that estimating the fastest rate of convergence to consensus of so-called leader follower systems leads to a consideration of the same optimization problem. The set function F to be minimized is supermodular and therefore the greedy algorithm is commonly used to construct optimal sets or their approximations. In this paper, the problem is reformulated so that the search for solutions is restricted to optimal and near optimal subsets of the graph. We prove sufficient conditions for the existence of a greedoid structure that contains feasible optimal and near optimal sets. It is therefore possible we conjecture, to search for optimal or near optimal sets by local moves in a stepwise manner to obtain near optimal sets that are better approximations than the factor (1−1/e) degree of optimality guaranteed by the use of the greedy algorithm. A simple example illustrates aspects of the method. 1 Random Walk Consensus Model Given a connected graph G = (V,E), with vertices or nodes V and edges E, we imagine a random walker situated at a node i ∈ V, moving to another node j ∈ V in a single discrete time step. The choice of j is random and has probability, Prob{i → j} = pij> 0, if (i, j) ∈ E pij = 0 otherwise. (1) The matrix P = (pij)i,j=1···N is the transition matrix of a Markov chain which in this paper, is assumed to be irreducible and aperiodic ([7]). N is the number of nodes and as in [1] the spread of information is described in terms of a process that is dual to the movement from informed to uninformed nodes. A random walk begins outside a pre-determined set A of informed target nodes 1 ar X i
Structure of unsteady stably stratified turbulence with mean shear.
No full textThe statistics of unsteady turbulence with uniform stratification N (Brunt–Väisälä frequency) and shear α(=dU1/dx3) are analysed over the entire time range (00 and \it Ri>0.25 respectively, oscillatory momentum and positive and negative density fluxes develop. Above a critical value of \it Ri\scriptsize\it crit(∼0.3), their average values are persistently countergradient. This structural change in the turbulence is the primary mechanism whereby stable stratification reduces the fluxes and the production of variances. It is quite universal and differs from the energy and stability mechanisms of Richardson (1926) and Taylor (1931). The long-time asymptotics of the energy ratio ER(=\it PE/VKE) of the potential energy to the vertical kinetic energy generally decreases with \it Ri(≥0.25), reaching the smallest value of 3/2 when there is no shear (\it Ri→∞). For strong mean shear (\it Ri<0.25), RDT significantly overestimates ER since (as in unstratified shear flow) it underestimates the vertical kinetic energy VKE. The RDT results show that the asymptotic values of the energy ratio ER and the normalized vertical density flux are independent of the initial value of ER, in agreement with DNS. This independence of the initial condition occurs because the ratios of the contributions from the initial values PE0 and KE0 are the same for PE and VKE and can be explained by the linear processes. Stable stratification generates buoyancy oscillations in the direction of the energy propagation of the internal gravity wave and suppresses the generation of turbulence by mean shear. Because the shear distorts the wavenumber fluctuations, the low-wavenumber spectrum of the vertical kinetic energy has the general form E33(k)∝(αtk)−1, where (LXαt)−1≪k≪L−1X (LX: integral scale). The viscous decay is controlled by the shear, so that the components of larger streamwise wavenumber k1 decay faster. Then, combined with the spectrum distortion by the shear, the energy and the flux are increasingly dominated by the small-k1 components as time elapses. They oscillate at the buoyancy period π/N because even in a shear flow the components as k1→0 are weakly affected by the shear. The effects of stratification N and shear α at small scales are to reduce both VKE and PE. Even for the same \it Ri, larger N and α reduce the high-wavenumber components of VKE and PE. This supports the applicability of the linear assumption for large N and α. At large scales, the stratification and shear effects oppose each other, i.e. both VKE and PE decrease due to the stratification but they increase due to the shear. We conclude that certain of these unsteady results can be applied directly to estimate the properties of sheared turbulence in a statistically steady state, but others can only be applied qualitatively
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