789 resultados para Life style distribution


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An investigation into predicting failure of pneumatic conveyor pipe bends due to hard solid particle impact erosion has been carried out on an industrial scale test rig. The bend puncture point locations may vary with many factors. However, bend orientation was suspected of being a main factor due to the biased particle distribution pattern of a high concentration flow. In this paper, puncture point locations have been studied with different pipe bend orientations and geometry (a solids loading ratio of 10 being used for the high concentration flow). Test results confirmed that the puncture point location is indeed most significantly influenced by the bend orientation (especially for a high concentration flow) due to the biased particle distribution and biased particle flux distribution.

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On the theatricality of dining room design between the wars

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The main purpose of this paper is to provide the core description of the modelling exercise within the Shelf Edge Advection Mortality And Recruitment (SEAMAR) programme. An individual-based model (IBM) was developed for the prediction of year-to-year survival of the early life-history stages of mackerel (Scomber scombrus) in the eastern North Atlantic. The IBM is one of two components of the model system. The first component is a circulation model to provide physical input data for the IBM. The circulation model is a geographical variant of the HAMburg Shelf Ocean Model (HAMSOM). The second component is the IBM, which is an i-space configuration model in which large numbers of individuals are followed as discrete entities to simulate the transport, growth and mortality of mackerel eggs, larvae and post-larvae. Larval and post-larval growth is modelled as a function of length, temperature and food distribution; mortality is modelled as a function of length and absolute growth rate. Each particle is considered as a super-individual representing 10 super(6) eggs at the outset of the simulation, and then declining according to the mortality function. Simulations were carried out for the years 1998-2000. Results showed concentrations of particles at Porcupine Bank and the adjacent Irish shelf, along the Celtic Sea shelf-edge, and in the southern Bay of Biscay. High survival was observed only at Porcupine and the adjacent shelf areas, and, more patchily, around the coastal margin of Biscay. The low survival along the shelf-edge of the Celtic Sea was due to the consistently low estimates of food availability in that area.

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The spawning stock of blue whiting (Micromesistius poutassou), an economically important pelagic gadoid in the North Atlantic Ocean, increased threefold after 1995. The reproductive success of the stock is largely determined during the very early stages of life, but little is known about the spawning dynamics of this species. Here we show that the spawning distribution of blue whiting is variable, regulated by the hydrography west of the British Isles. When the North Atlantic subpolar gyre is strong and spreads its cold, fresh water masses east over Rockall Plateau, the spawning is constrained along the European continental slope and in a southerly position near Porcupine Bank. When the gyre is weak and conditions are relatively saline and warm, the spawning distribution moves northwards along the slope and especially westwards covering Rockall Plateau. The apparent link between the spawning distribution and the subpolar gyre is the first step towards understanding the reproduction variability, which currently is the main challenge for appropriate management of the blue whiting stock.

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Increasing availability and extent of biological ocean time series (from both in situ and satellite data) have helped reveal significant phenological variability of marine plankton. The extent to which the range of this variability is modified as a result of climate change is of obvious importance. Here we summarize recent research results on phenology of both phytoplankton and zooplankton. We suggest directions to better quantify and monitor future plankton phenology shifts, including (i) examining the main mode of expected future changes (ecological shifts in timing and spatial distribution to accommodate fixed environmental niches vs. evolutionary adaptation of timing controls to maintain fixed biogeography and seasonality), (ii) broader understanding of phenology at the species and community level (e.g. for zooplankton beyond Calanus and for phytoplankton beyond chlorophyll), (iii) improving and diversifying statistical metrics for indexing timing and trophic synchrony and (iv) improved consideration of spatio-temporal scales and the Lagrangian nature of plankton assemblages to separate time from space changes.

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Addressing the multitude of challenges in marine policy requires an integrated approach that considers the multitude of drivers, pressures, and interests, from several disciplinary angles. Scenarios are needed to harmonise the analyses of different components of the marine system, and to deal with the uncertainty and complexity of the societal and biogeophysical dynamics in the system. This study considers a set of socio-economic scenarios to (1) explore possible futures in relation to marine invasive species, outbreak forming species, and gradual changes in species distribution and productivity; and (2) harmonise the projection modelling performed within associated studies. The exercise demonstrates that developing interdisciplinary scenarios as developed in this study is particularly complicated due to (1) the wide variety in endogeneity or exogeneity of variables in the different analyses involved; (2) the dual role of policy decisions as variables in a scenario or decisions to be evaluated and compared to other decisions; and (3) the substantial difference in time scale between societal and physical drivers.

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A group of children identified as non-organic failure-to-thrive between 1977 and 1980 were investigated, assessed and provided with social work intervention and treatment. Those children and their families have been followed up for the last 20 years. The current paper examines the stability of an internal working model in a sample of individuals who had failed to thrive as children, by comparing each individual's adult attachment style with their childhood attachment to their mother. In this sample, several cases showed changes from insecure to secure attachment styles. Possible reasons are discussed for positive and negative changes, as well as cases when there was no change in attachment style. These include the effectiveness of intervention in addition to changes in life circumstances. The findings suggest that when appropriate support and intervention is provided, or when different circumstances or relationships are experienced, internal working models can change.

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Conceptual art and communicator role has influenced the work of Chilean architect Alfredo Jaar, which has been proposed report, with other codes [verbal and nonverbal], global events influencing contemporary society. His early training as an architect has driven innovation in the design of artistic space , using the message to convey to the viewer the reason for his work for more than three decades, highlights the artistic composition with various material resources whose purpose lies in conceptualizing various topics relevant in considering the role of artistic communication. Jaar’s style is the sum of his own life experience in relation to the contradictions of the world today, which is exposed and from the perspective of postmodernism from the exploitation of the notion of space as an open stage for visual and expressiveness beyond national borders, societies and cultures of the world.

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Actualmente Ai Weiwei es el creador con mayor proyección dentro y fuera de China, destacando especialmente por su prolífica, heterogénea, comprometida y polémica producción artística. Sus propuestas suscitan un gran interés y obtienen una destacada repercusión tanto en China como en un escenario internacional. Precisamente, es uno de los artistas contemporáneos chinos que ha logrado una mayor presencia en los medios de comunicación y en los espacios expositivos españoles, siendo un ejemplo de ello la organización de la primera exposición museística de su obra en el Centro Andaluz de Arte Contemporáneo (2013) y el estreno de la película documental sobre su vida y su obra Never Sorry (2013), dirigida por Alison Klayman. Ai Weiwei es un autor mediático y su visibilidad deviene una plataforma desde donde articular proyectos artísticos que enfocan determinadas problemáticas sociales. A la vez, la crítica política de Ai Weiwei resulta especialmente atractiva en un contexto euroamericano que subraya su papel de disidente y agitador. Dentro de tales parámetros se ahondará en la recepción de la producción artística de Ai Weiwei en el marco internacional y en el contexto español, analizando la aproximación que la prensa esboza sobre dicho autor.

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1. We collated information from the literature on life history traits of the roach (a generalist freshwater fish), and analysed variation in absolute fecundity, von Bertalanffy parameters, and reproductive lifespan in relation to latitude, using both linear and non-linear regression models. We hypothesized that because most life history traits are dependent on growth rate, and growth rate is non-linearly related with temperature, it was likely that when analysed over the whole distribution range of roach, variation in key life history traits would show non-linear patterns with latitude.

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A single thallus of the rare red seaweed Tsengia bairdii (Farlow) K. Fan et Y.Fan( Platoma bairdii (Farlow) Kuckuck) (Nemastomataceae) was collected on a subtidal pebble on the west coast of Scotland. The terete gelatinous axes, which were only 7 mm high, were monoecious. They bore numerous cystocarps and a few spermatangia, which represent the first observation of male structures in this genus. Released carpospores grew into expanded basal discs that gave rise to erect axes bearing irregularly cruciate tetrasporangia. irregularly cruciate to zonate tetrasporangia were also formed on these basal discs. Karyological studies on dividing tetrasporocytes showed about 25 bodies, identified as paired meiotic chromosomes on the basis of their size in comparison to mitotic and meiotic chromosomes in other red algal species. These observations confirm the isomorphic life history inferred from early field collections and show that this species is monoecious. Tsengia bairdii is an extremely rare seaweed in Europe - it seems to be confined to sublittoral cobbles and has a temporally patchy distribution.

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In this paper we seek to contribute to recent efforts to develop and implement multi-dimensional approaches to social exclusion by applying self-organising maps (SOMs) to a set of material deprivation indicators from the Irish component of EU-SILC. The first stage of our analysis involves the identification of sixteen clusters that confirm the multi-dimensional nature of deprivation in contemporary Ireland and the limitations of focusing solely on income. In going beyond this mapping stage, we consider both patterns of socio-economic differentiation in relation to cluster membership and the extent to which such membership contributes to our understanding of economic stress. Our analysis makes clear the continuing importance of traditional forms of stratification relating to factors such as income, social class and housing tenure in accounting for patterns of multiple deprivation. However, it also confirms the role of acute life events and life cycle and location influences. Most importantly, it demonstrates that conclusions relating to the relative impact of different kinds of socio-economic influences are highly dependent on the form of deprivation being considered. Our analysis suggests that debates relating to the extent to which poverty and social exclusion have become individualized should take particular care to distinguish between different kinds of outcomes. Further analysis demonstrates that the SOM approach is considerably more successful than a comparable latent class analysis in identifying those exposed to subjective economic stress. (C) 2010 International Sociological Association Research Committee 28 on Social Stratification and Mobility. Published by Elsevier Ltd. All rights reserved.

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In the presence of anthropogenic climate change, gross environmental degradation, and mass abject poverty, many political theorists currently debate issues such as people's right to water, the right to food, and the distribution of rights to natural resources more generally. However, thus far many theorists either focus (somewhat arbitrarily) only on one particular resource (e.g. water) or they treat all natural resources alike, meaning that many relevant distinctions within the group of natural resources are overlooked. Hence, the paper will start with an analysis of the various forms which natural resources can take and how this might influence one's conception of resource rights. In so doing, the paper argues that we have to carefully distinguish between the actual physical resources people might control and how we distribute these, and the life-sustaining benefits each and every person draws from sustainable and functioning ecosystems. Based on this distinction, the paper will argue for a right to the benefits of life-sustaining ecosystem services as a universal basic right every person has. Further distributive claims with respect to particular physical resources would thus be limited by the requirements of such a basic right.

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Knowledge on the life span of the riveting dies used in the automotive industry is sparse. It is often the case that only when faulty products are produced are workers aware that their tool needs to be changed. This is of course costly both in terms of time and money. Responding to this challenge, this paper proposes a methodology which integrates wear and stress analysis to quantify the life of a riveting die. Experiments are carried out to measure the applied load required to split a rivet. The obtained results (i.e. force curves) are used to validate the wear mechanisms of the die observed using scanning electron microscopy. Sliding, impact, and adhesive wears are observed on the riveting die after a certain number of riveting cycles. The stress distribution on the die during riveting is simulated using a finite element (FE) approach. In order to confirm the accuracy of the FE model, the experimental force results are compared with the ones produced from FE simulation. The maximum and minimum von Mises' stresses generated from the FE model are input into a Goodman diagram and an S-N curve to compute the life of the riveting die. It is found that the riveting die is predicted to run for 4 980 000 cycles before failure.

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The accurate definition of the extreme wave loads which act on offshore structures represents a significant challenge for design engineers and even with decades of empirical data to base designs upon there are still failures attributed to wave loading. The environmental conditions which cause these loads are infrequent and highly non-linear which means that they are not well understood or simple to describe. If the structure is large enough to affect the incident wave significantly further non-linear effects can influence the loading. Moreover if the structure is floating and excited by the wave field then its responses, which are also likely to be highly non-linear, must be included in the analysis. This makes the description of the loading on such a structure difficult to determine and the design codes will often suggest employing various tools including small scale experiments, numerical and analytical methods, as well as empirical data if available.
Wave Energy Converters (WECs) are a new class of offshore structure which pose new design challenges, lacking the design codes and empirical data found in other industries. These machines are located in highly exposed and energetic sites, designed to be excited by the waves and will be expected to withstand extreme conditions over their 25 year design life. One such WEC is being developed by Aquamarine Power Ltd and is called Oyster. Oyster is a buoyant flap which is hinged close to the seabed, in water depths of 10 to 15m, piercing the water surface. The flap is driven back and forth by the action of the waves and this mechanical energy is then converted to electricity.
It has been identified in previous experiments that Oyster is not only subject to wave impacts but it occasionally slams into the water surface with high angular velocity. This slamming effect has been identified as an extreme load case and work is ongoing to describe it in terms of the pressure exerted on the outer skin and the transfer of this short duration impulsive load through various parts of the structure.
This paper describes a series of 40th scale experiments undertaken to investigate the pressure on the face of the flap during the slamming event. A vertical array of pressure sensors are used to measure the pressure exerted on the flap. Characteristics of the slam pressure such as the rise time, magnitude, spatial distribution and temporal evolution are revealed. Similarities are drawn between this slamming phenomenon and the classical water entry problems, such as ship hull slamming. With this similitude identified, common analytical tools are used to predict the slam pressure which is compared to that measured in the experiment.