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Selection Principle (selection + principle)
Selected AbstractsInconsistent use of host plants by the Alaskan swallowtail butterfly: adult preference experiments suggest labile oviposition strategyECOLOGICAL ENTOMOLOGY, Issue 2 2007SHANNON M. MURPHY Abstract 1.,The Alaskan swallowtail butterfly (Papilio machaon aliaska) uses three unrelated plant species as hosts: Cnidium cnidiifolium (Apiaceae), Artemisia arctica (Asteraceae), and Petasites frigidus (Asteraceae). The research presented here investigated whether there are any consistent patterns in host choice by P. m. aliaska females. 2.,The first two experiments were designed to test if P. m. aliaska host preference is constant or if it changes from day to day. If host preference is labile, the experiments were designed to also test whether a female's diet breadth narrows or expands over time. 3.,The third experiment tested the host preferences of female offspring from several wild-caught P. m. aliaska females. If P. m. aliaska individuals are specialised in their host use, then all of the offspring from a single female would likely prefer the same host-plant species. This experiment was also designed to test the Hopkins' host selection principle; does the food plant on which a female is reared as a larva influence her future choices when she is searching for host plants for her own offspring? 4.,The results from all of these experiments indicate that P. m. aliaska females vary greatly in their oviposition behaviour and in their preferences for the three host plants. Most populations appear to consist of generalists with labile oviposition behaviour. There is no evidence to support the Hopkins' host selection principle. 5.,It is suggested that the generalised selection of host plants by P. m. aliaska females may be a ,bet-hedging' strategy and that this strategy may maximise reproductive fitness in an unpredictable environment. [source] Amplitude-only pattern nulling of linear antenna arrays with the use of an immune algorithmINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2008Kerim Guney Abstract This article presents an optimization immune algorithm (opt-IA) for null steering of linear antenna arrays by controlling only the element amplitudes. Nulling of the pattern is also achieved by controlling the phase-only and the complex weights (both the amplitude and phase) of the array elements. The opt-IA is a new evolutionary computing algorithm based on the clonal selection principle of immune system. To show the accuracy and flexibility of the proposed opt-IA, several examples of Chebyshev array pattern with the imposed single, multiple, and broad nulls are given. It is found that the nulling technique based on opt-IA is capable of steering the array nulls precisely to the undesired interference directions. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008. [source] Multispecies conservation planning: identifying landscapes for the conservation of viable populations using local and continental species prioritiesJOURNAL OF APPLIED ECOLOGY, Issue 2 2007REGAN EARLY Summary 1Faced with unpredictable environmental change, conservation managers face the dual challenges of protecting species throughout their ranges and protecting areas where populations are most likely to persist in the long term. The former can be achieved by protecting locally rare species, to the potential detriment of protecting species where they are least endangered and most likely to survive in the long term. 2Using British butterflies as a model system, we compared the efficacy of two methods of identifying persistent areas of species' distributions: a single-species approach and a new multispecies prioritization tool called ZONATION. This tool identifies priority areas using population dynamic principles (prioritizing areas that contain concentrations of populations of each species) and the reserve selection principle of complementarity. 3ZONATION was generally able to identify the best landscapes for target (i.e. conservation priority) species. This ability was improved by assigning higher numerical weights to target species and implementing a clustering procedure to identify coherent biological management units. 4Weighting British species according to their European rather than UK status substantially increased the protection offered to species at risk throughout Europe. The representation of species that are rare or at risk in the UK, but not in Europe, was not greatly reduced when European weights were used, although some species of UK-only concern were no longer assigned protection inside their best landscapes. The analysis highlights potential consequences of implementing parochial vs. wider-world priorities within a region. 5Synthesis and applications. Wherever possible, reserve planning should incorporate an understanding of population processes to identify areas that are likely to support persistent populations. While the multispecies prioritization tool ZONATION compared favourably to the selection of ,best' areas for individual species, a user-defined input of species weights was required to produce satisfactory solutions for long-term conservation. Weighting species can allow international conservation priorities to be incorporated into regional action plans but the potential consequences of any putative solution should always be assessed to ensure that no individual species of local concern will be threatened. [source] ,An important obligation of citizenship': language, citizenship and jury serviceLEGAL STUDIES, Issue 2 2007R Gwynedd Parry This paper considers whether there should be the power to summon bilingual juries in criminal trials in Ireland and Wales. It will examine the relationship between jury service as an obligation and privilege of citizenship, and the eligibility for jury service of Irish and Welsh speakers as a linguistic group. It will also demonstrate the relationship between the citizenship argument in its collective context and the rights and interests of individual speakers of these languages within the criminal jury trial process. In doing so, it seeks to emphasise that this is a multidimensional issue which requires an evaluation from a combination of perspectives, both collective and individual. It is this combination of perspectives, taken conjunctively, that supports the case for bilingual juries. Moreover, this particular debate has a particular relevance to the wider debate on European citizenship and how Europe views the concept of multilingual citizenship within its constitutional framework. Indeed, it raises fundamental questions about how Europe manages its diverse cultural and linguistic heritage and how speakers of minority languages are integrated on a basis of equality and respect towards their cultural and linguistic autonomy. The paper also addresses the objections to bilingual juries and will explore how the advent of bilingual juries could continue to preserve the random selection principle (the primary objection to bilingual juries) sufficiently to bring about fair, impartial and competent tribunals. [source] | ||||||||||