Home About us Contact
|
Home About us Contact | ||
|
|
||
Current Context (current + context)
Selected AbstractsNiche breadth, competitive strength and range size of tree species: a trade-off based framework to understand species distributionECOLOGY LETTERS, Issue 2 2006Xavier Morin Abstract Understanding the mechanisms causing latitudinal gradients in species richness and species range size is a central issue in ecology, particularly in the current context of global climate change. Different hypotheses have been put forward to explain these patterns, emphasizing climatic variability, energy availability and competition. Here we show, using a comparative analysis controlling for phylogeny on 234 temperate/boreal tree species, that these hypotheses can be included into a single framework in an attempt to explain latitudinal gradients in species range size. We find that species tend to have larger ranges when (i) closer to the poles, (ii) successionally seral, (iii) having small and light seeds, and (iv) having short generations. The patterns can simply be explained by energy constraints associated with different life-history strategies. Overall, these findings shed a new light on our understanding of species distribution and biodiversity patterns, bringing new insights into underlying large-scale evolutionary processes. [source] From Milah (Circumcision) to Milah (Word): Male Identity and Rituals of Childhood in the Jewish Ultraorthodox CommunityETHOS, Issue 2 2003Professor Yoram Bilu In contemporary Jewish ultraorthodox communities, most three-year-old male children undergo a twofold ritual sequence in which the first haircut is associated with entering the world of study. Focusing on the paramount value of holy Torah study and its prerequisites, I seek to decode the psychocultural meanings of the haircutting and school initiation ceremonies and their ceremonial antecedent, circumcision, as markers on the male trajectory from milah (circumcision) to milah (word). The ritual sequence is evaluated comparatively against the widespread conception of manhood as a special-status category of achievement that requires indoctrination and testing. In order to account for the recent proliferation of the rituals, an attempt is made to situate them historically in the current context of contemporary ultraorthodox and Israeli society. [source] Constitutionalism and Dissonances: Has Europe Paid Off Its Debt to Functionalism?EUROPEAN LAW JOURNAL, Issue 3 2009Marco Dani This impression seems confirmed by the recent Presidency Conclusions of the European Council which, although salvaging many important solutions contained in the Constitutional Treaty, explicitly sanction that ,the constitutional concept . . . is abandoned'. In the light of this context, what role could the constitutional scholarship play? How to make sense of a polity in which the claims of constitutionalism as a form of power are politically unappealing though legally plausible? This article tries to respond to these questions by reaffirming functionalism as a valid analytical and normative perspective in facing the current constitutional reality of European integration. The analytical value associated with functionalism is evidenced by testing against the current context of the EU legal framework the accounts for EU constitutionalism which postulate functional equivalence between the EU and the Member States. The normative potential of functionalism, then, is discussed by arguing that there may be a value worth preserving in a degree of functional discrepancy between the EU and state constitutionalism and, notably, that the transformative and civilising dividend inherent in functionalism could still be exploited, at least in certain areas of EU policy making. Finally, the article suggests that the difficulties in accounting for EU constitutionalism in the light of state-centred constitutional theory could be regarded as symptoms of European integration marking a moment in the theoretical evolution of constitutionalism. [source] On the (In)Compatibility of Guilt and Suffering in German Memory1GERMAN LIFE AND LETTERS, Issue 2 2006Aleida Assmann This article analyses the current shift in German memory concerning the issue of German suffering at the end of the Second World War. Contrary to widely held belief, these themes are not novel: German suffering was a topic of discourse immediately after the war in the private and political sphere. What is new in the current context, however, is the intensity of the unexpected return of these issues and their wide social resonance among different classes and generations. With this shift in focus, new memory contests arise. One paradigmatic case is the polarity created between a memory of German guilt and a memory of German suffering as represented by the two popular historians Hannes Heer and Jörg Friedrich; another concerns the (still ongoing) debate around a new centre for flight and expulsion. It is argued that the impasse of recent cultural memory debate typified by Heer and Friedrich can be surpassed by a more complex understanding of the structure of memory. According to this view, various levels of heterogeneous memory can exist side by side if they are contained within a normative frame of generally accepted validity. [source] Research and theory on high-performance work systems: progressing the high-involvement streamHUMAN RESOURCE MANAGEMENT JOURNAL, Issue 1 2009Peter Boxall The notion of a high-performance work system (HPWS) constitutes a claim that there exists a system of work practices for core workers in an organisation that leads in some way to superior performance. In this article, we dissect this fuzzy notion and examine its companion terminology: high-involvement work systems and high-commitment management. We argue that a focus on the high-involvement stream usefully grounds HPWS studies in an important area of workplace change in the current context and takes us away from eclectic and contentious selections of ,best practices'. We review research models and findings in this stream. The path to better research lies in examining the underpinning processes experienced by workers when management seeks to pursue high-involvement systems, and charting their links to employee and operational outcomes. [source] Art & Design:The Rhetoric and the PracticeINTERNATIONAL JOURNAL OF ART & DESIGN EDUCATION, Issue 1 2000John Bowden In this paper I will outline what I perceive to be the current context in which Art and Design activities operate in Primary and Secondary Schools in England. I will argue that significant advances in the teaching of the subject in the last two decades are being threatened, particularly in the primary sector, due to the impact of a number of factors, including the new ,standards' agenda, and constraints arising from limitations in resources, teaching expertise and deployment, and the effects of assessment. The under achievement of boys will be considered in relation to some observations on differentiation in the subject at Secondary level. The paper will suggest that the attempts by teachers to offer an art curriculum that covers all aspects of artistic activity has led to a superficiality of experience for pupils, and therefore a ,depth' rather than a breadth approach to art curriculum planning is now necessary. The variable impact of Critical Studies activities will be considered, including that of Artists in Schools, and I will suggest that there is an opportunity to extend current art practice encouraging greater risk-taking, through an open-ended problem-solving approach, and a development of work which celebrates pupils' own cultures and interests. [source] Value-centric framework and pareto optimality for design and acquisition of communication satellitesINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 6 2009Joy Brathwaite Abstract Investments in space systems are substantial, indivisible, and irreversible, characteristics of high-risk investments. Traditional approaches to system design, acquisition, and risk mitigation are derived from a cost-centric mindset, and as such they incorporate little information about the value of the spacecraft to its stakeholders. These traditional approaches are appropriate in stable environments. However, the current technical and economic conditions are distinctly uncertain and rapidly changing. Consequently, these traditional approaches have to be revisited and adapted to the current context. We propose that in uncertain environments, decision-making with respect to design and acquisition choices should be value-based. We develop a value-centric framework, analytical tools, and an illustrative numerical example for communication satellites. Our two proposed metrics for decision-making are the system's expected value and value uncertainty. Expected value is calculated as the expected NPV of the satellite. The cash inflow is calculated as a function of the satellite loading, its transponder pricing, and market demand. The cash outflows are the various costs for owning and operating the satellite. Value uncertainty emerges due to uncertainties in the various cash flow streams, in particular because of market conditions. We propagate market uncertainty through Monte Carlo simulation, and translate it into value uncertainty for the satellite. The end result is a portfolio of Pareto-optimal satellite design alternatives. By using value and value uncertainty as decision metrics in the down-selection process, decision-makers draw on more information about the system in its environment, and in making value-based design and acquisition choices, they ultimately make more informed and better choices. Copyright © 2009 John Wiley & Sons, Ltd. [source] Matching Technologies with Potential End Users: A Knowledge Engineering Approach for Agricultural Research ManagementJOURNAL OF AGRICULTURAL ECONOMICS, Issue 1 2004J. David Reece This paper addresses the problem of priority setting that faces developing country agricultural research, a problem whose relevance has been sharpened by the current context of demands for greater efficiency and targeted impact. A new method for ex ante estimation of the impact of developing each of several alternative proposed technologies is described and illustrated through an example from West Africa. This method is based on the notion of market segmentation, which normally makes intensive use of secondary data-sets that are simply not available for rural areas of developing countries. To circumvent this lack of secondary data, the method adopts a knowledge engineering approach based on the views of an expert panel familiar with the region to be served. Descriptions of proposed technologies are matched with the interests and resources of identified market segments, together with the characteristics of their farming systems and locations, to identify those segments whose members are likely to use the proposed technology. Further development of the method is discussed. [source] REVIEW: The identification of priority policy options for UK nature conservationJOURNAL OF APPLIED ECOLOGY, Issue 5 2010William J. Sutherland Summary 1.,The conservation of biodiversity depends upon both policy and regulatory frameworks. Here, we identify priority policy developments that would support conservation in the UK in the light of technological developments, changes in knowledge or environmental change. 2.,A team of seven representatives from governmental organizations, 17 from non-governmental organizations and six academics provided an assessment of the priority issues. The representatives consulted widely and identified a long-list of 117 issues. 3.,Following voting and discussion during a 2-day meeting, these were reduced to a final list of 25 issues and their potential policy options and research needs were identified. Many of the policies related to recent changes in approaches to conservation, such as increased interest in ecosystem services, adaptation to climate change and landscape ecology. 4.,We anticipate that this paper will be useful for policy makers, nature conservation delivery agencies, the research community and conservation policy advocates. 5.,Although many of the options have global significance, we suggest that other countries consider an equivalent exercise. We recommend that such an exercise be carried out in the UK at regular intervals, say every 5 years, to explore how biodiversity conservation can best be supported by linked policy development and research in a changing world. 6.,Synthesis and applications. Opportunities for policy development were prioritized and for each of the top 25 we identified the current context, policy options and research questions. These largely addressed new issues relating to developing topics such as ecosystem services, landscape planning and nanotechnology. We envisage that this will largely be used by researchers wishing to make a contribution to potential policy debates. [source] Where do the feral oilseed rape populations come from?JOURNAL OF APPLIED ECOLOGY, Issue 2 2008A large-scale study of their possible origin in a farmland area Summary 1Many cultivated species can escape from fields and colonize seminatural habitats as feral populations. Of these, feral oilseed rape is a widespread feature of field margins and roadside verges. Although considered in several studies, the general processes leading to the escape and persistence of feral oilseed rape are still poorly known. Notably, it remains unclear whether these annuals form transient populations resulting mainly from seed immigration (either from neighbouring fields or during seed transport), or whether they show real ability to persist (either through self-recruitment or seed banks). 2We conducted a 4-year large-scale study of factors involved in the presence of feral oilseed rape populations in a typical open-field area of France. The results were subjected to statistical methods suitable for analysing large data sets, based on a regression approach. We subsequently addressed the relative contribution of the ecological processes identified as being involved in the presence of feral populations. 3Many feral oilseed rape populations resulted from seed immigration from neighbouring fields (about 35,40% of the observed feral populations). Immigration occurred at harvest time rather than at sowing. Around 15% of such populations were attributed to immigration through seed transport. 4The other half resulted from processes of persistence, mainly through persistent seed banks (35,40% of the observed feral populations). This was all the more unexpected because seed banks have not yet been documented on road verges (despite being frequent within fields). Local recruitment was rare, accounting for no more than 10% of the feral populations. 5Synthesis and applications. Understanding the dynamics of feral oilseed rape populations is crucial for evaluating gene flow over an agro-ecosystem. Our results show that, while many feral populations do come from annual seed dispersal, a significant number also result from seeds stored in the soil for several years. In the current context of coexistence and management of transgenic with non-transgenic crops, feral persistence and, especially, the seed bank contribution to the dynamics of feral populations need to be considered seriously. The latter, combined with self-recruitment, indicates a high potential for the persistence of transgenes and the possible emergence of gene-stacking. [source] Current issues with fish and fisheries: editor's overview and introductionJOURNAL OF APPLIED ECOLOGY, Issue 2 2003S. J. Ormerod Summary 1.,By any measure, fishes are among the world's most important natural resources. Annual exploitation from wild populations exceeds 90 million tonnes, and fish supply over 15% of global protein needs as part of total annual trade exceeding $US 55 billion. Additionally, with over 25 000 known species, the biodiversity and ecological roles of fishes are being increasingly recognised in aquatic conservation, ecosystem management, restoration and aquatic environmental regulation. 2.,At the same time, substantial management problems now affect the production, exploitable stocks, global diversity, trophic structure, habitat quality and local composition of fish communities. 3.,In marine systems, key issues include the direct effects of exploitation on fish, habitats and other organisms, while habitat or water quality problems arise also from the atmospheric, terrestrial and coastal environments to which marine systems are linked. In freshwaters, flow regulation and obstruction by dams, fragmentation, catchment management, pollution, habitat alterations, exotic fish introductions and nursery-reared fish are widespread issues. 4.,Management responses to the problems of fish and fisheries include aquatic reserves in both marine and freshwater habitats, and their effectiveness is now being evaluated. Policies on marine exploitation increasingly emphasise fishes as integral components of aquatic ecosystems rather than individually exploitable stocks, but the rationalisation of fishing pressures presents many challenges. In Europe, North America and elsewhere, policies on freshwaters encourage habitat protection, integrated watershed management and restoration, but pressures on water resources will cause continued change. All these management approaches require development and evaluation, and will benefit from a perspective of ecological understanding with ecologists fully involved. 5.,Synthesis and applications. Although making a small contribution to the Journal of Applied Ecology in the past, leading work on aquatic problems and fish-related themes appear increasingly in this and other mainstream ecology journals. As this special profile of five papers shows, significant contributions arise on diverse issues that here include the benefit of aquatic reserves, river restoration for fish, the accumulation of contaminants, interactions with predators, and the fitness of salmonids from nurseries. This overview outlines the current context in which papers on the applied ecology of fish and fisheries are emerging, and it identifies scope for further contributions. [source] The end of regressive evolution: examining and interpreting the evidence from cave fishesJOURNAL OF FISH BIOLOGY, Issue 1 2005A. Romero The evolution of hypogean fauna in general and hypogean fishes in particular has been controversial. Explanations regarding the reduction or loss of phenotypic characters such as eyes and pigmentation range from neo-Lamarckism to neutral mutations, with ,regressive evolution' being a catch-all characterization for such processes. The assumptions required for special evolutionary mechanisms underlying the evolution of cave dwellers have been based on generalizations about the animals and their environments drawn from relatively few observations. The evidence offered for notions such as pre-adaptation of colonizing fauna and the purported impoverished nutrients in all caves is examined and it appears that the generalizations cannot be supported. Some major accomplishments in field and laboratory studies of hypogean fishes are summarized, including work highlighting developmental phenotypic plasticity. At the end, it is argued that evolution of hypogean fauna can be explained by well-known mechanisms within the current context of evolutionary biology. [source] The Language That Came Down the Hill: Slang, Crime, and Citizenship in Rio de JaneiroAMERICAN ANTHROPOLOGIST, Issue 1 2009Jennifer Roth-Gordon ABSTRACT, In Rio de Janeiro, Brazil, the register of slang has historically been embraced to forge salient social and spatial distinctions, demarcating the physical space of the favela (shantytown) and naturalizing the exclusion of its residents. In this article, I examine the ongoing enregisterment of slang in Rio's current context of profound social inequality, democratic instability, heightened urban violence, and geographic proximity. Within this climate of fear and insecurity, newly vulnerable and newly marginalized city residents draw on and reify salient speech repertoires to negotiate rights to the city and to the nation-state that have become increasingly threatened along socioeconomic, racial, and residential lines. I argue that the enregisterment of slang constructs newly emergent citizenship categories that both challenge and reinforce Brazil's entrenched regime of differentiated citizenship, illuminating the productive role of linguistic differentiation in the modern nation-state. [Keywords: slang, crime, citizenship, marginality, Brazil] [source] EVOLUTION OF BIRD SONG AFFECTS SIGNAL EFFICACY: AN EXPERIMENTAL TEST USING HISTORICAL AND CURRENT SIGNALSEVOLUTION, Issue 8 2007Elizabeth P. Derryberry Mating signals act as behavioral barriers to gene flow in many animal taxa, yet little is known about how signal evolution within populations contributes to the formation of these barriers. Although variation in mating signals among populations is known to affect mating behavior, there is no direct evidence that the evolution of mating signals changes signal effectiveness within a natural population. Making use of historical recordings of bird song, I found that both male and female white-crowned sparrows (Zonotrichia leucophrys) respond more strongly to current than to historical songs, indicating that historical songs are less effective as signals in the current contexts of both mate choice and male,male competition. Finding that historical signals are less effective suggests that signal evolution within populations may ultimately contribute to the formation of behavioral barriers to gene flow between populations. [source] | ||||||||||||||||