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Selected AbstractsThe role of quantitative and qualitative research in industrial studies of tourismINTERNATIONAL JOURNAL OF TOURISM RESEARCH, Issue 2 2003Brian Davies Abstract Many areas of research in tourism concentrate on quantitative or qualitative studies. Some even discuss the complementarity between the two types of studies. Hardly considered are the possibilities for combining such works within an integrated framework that also considers the business environment in which tourism operates. The purpose of this paper is to return to long neglected possibilities by reinvestigating areas of methodology and epistemology concerned with the generation of a framework that embraces both quantitative and qualitative research. A hypothetical example, in terms of industrial organisation and strategic decision making, is introduced discussing the possibilities for the triangulation of methods and paradigms and the role of the business environment. The conclusion is that an improved understanding of the tourism business requires a broader research methodology than presently exists. Both types of research and the dynamic context of tourism are important and need to be combined within an integrated framework. It has been concerned with the construction of integrating frameworks that embrace an alternative logic of inference and the context of the tourism business environment. This requires refinements of existing approaches together with a broader research methodology. Only by establishing such frameworks will an improved understanding of the tourism industry be achieved. The suggested framework presented here, with particular reference to industrial organisation and strategic decision making by tourism suppliers, is not offered as a panacea. For future work, the validity and choice of framework rest squarely on how the world and ,truth' are viewed. However, within this, the contribution of triangulated quantitative and qualitative research should help understanding by studying phenomena in their natural setting and in terms of the meanings people have of them. This should lead to a ,truer analysis' of business behaviour and hence a more purposeful investigation of hotels, tour operators, travel agents and the business of tourism in general. It is in seeking to produce this ,truer analysis' that future research activities need to concentrate. Copyright © 2003 John Wiley & Sons, Ltd. [source] On the nature and evolution of the neural bases of human languageAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue S35 2002Philip Lieberman Abstract The traditional theory equating the brain bases of language with Broca's and Wernicke's neocortical areas is wrong. Neural circuits linking activity in anatomically segregated populations of neurons in subcortical structures and the neocortex throughout the human brain regulate complex behaviors such as walking, talking, and comprehending the meaning of sentences. When we hear or read a word, neural structures involved in the perception or real-world associations of the word are activated as well as posterior cortical regions adjacent to Wernicke's area. Many areas of the neocortex and subcortical structures support the cortical-striatal-cortical circuits that confer complex syntactic ability, speech production, and a large vocabulary. However, many of these structures also form part of the neural circuits regulating other aspects of behavior. For example, the basal ganglia, which regulate motor control, are also crucial elements in the circuits that confer human linguistic ability andreasoning. The cerebellum, traditionally associated with motor control, is active in motor learning. The basal ganglia are also key elements in reward-based learning. Data from studies of Broca's aphasia, Parkinson's disease, hypoxia, focal brain damage, and a genetically transmitted brain anomaly (the putative "language gene," family KE), and from comparative studies of the brains and behavior of other species, demonstrate that the basal ganglia sequence the discrete elements that constitute a complete motor act, syntactic process, or thought process. Imaging studies of intact human subjects and electrophysiologic and tracer studies of the brains and behavior of other species confirm these findings. As Dobzansky put it, "Nothing in biology makes sense except in the light of evolution" (cited in Mayr, 1982). That applies with as much force to the human brain and the neural bases of language as it does to the human foot or jaw. The converse follows: the mark of evolution on the brains of human beings and other species provides insight into the evolution of the brain bases of human language. The neural substrate that regulated motor control in the common ancestor of apes and humans most likely was modified to enhance cognitive and linguistic ability. Speech communication played a central role in this process. However, the process that ultimately resulted in the human brain may have started when our earliest hominid ancestors began to walk. Yrbk Phys Anthropol 45:36,62, 2002. © 2002 Wiley-Liss, Inc. [source] A formalized approach for designing a P2P-based dynamic load balancing schemeCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 10 2010Hengheng Xie Abstract Quality of service (QoS) is attracting more and more attention in many areas, including entertainment, emergency services, transaction services, and so on. Therefore, the study of QoS-aware systems is becoming an important research topic in the area of distributed systems. In terms of load balancing, most of the existing QoS-related load balancing algorithms focus on Routing Mechanism and Traffic Engineering. However, research on QoS-aware task scheduling and service migration is very limited. In this paper, we propose a task scheduling algorithm using dynamic QoS properties, and we develop a Genetic Algorithm-based Services Migration scheme aiming to optimize the performance of our proposed QoS-aware distributed service-based system. In order to verify the efficiency of our scheme, we implement a prototype of our algorithm using a P2P-based JXTA technique, and do an emulation test and a simulation test in order to analyze our proposed solution. We compare our service-migration-based algorithm with non-migration and non-load-balancing approaches, and find that our solution is much better than the other two in terms of QoS success rate. Furthermore, in order to provide more solid proofs of our research, we use DEVS to validate our system design. Copyright © 2010 John Wiley & Sons, Ltd. [source] Design of a virtual environment aided by a model-based formal approach using DEVS,CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 11 2009Azzedine Boukerche Abstract Virtual environment (VE) is a modern computer technique that aims to provide an attracting and meaningful human,computer interacting platform, which can essentially help the human users to learn, to play or to be trained in a ,like-real' situation. Recent advances in VE techniques have resulted in their being widely used in many areas, in particular, the E-learning-based training applications. Many researchers have developed the techniques for designing and implementing the 3D virtual environment; however, the existing approaches cannot fully catch up the increasing complexity of modern VE applications. In this paper, we designed and implemented a very attracting web-based 3D virtual environment application that aims to help the training practice of personnel working in the radiology department of a hospital. Furthermore, we presented a model-based formal approach using discrete event system specification (DEVS) to help us in validating the X3D components' behavior. As a step further, DEVS also helps to optimize our design through simulating the design alternatives. Copyright © 2009 John Wiley & Sons, Ltd. [source] BUSINESS METHOD PATENTS AND U.S. FINANCIAL SERVICESCONTEMPORARY ECONOMIC POLICY, Issue 3 2010ROBERT M. HUNT A decade after the State Street decision, more than 1,000 business method patents are granted each year. Yet, only 1 in 10 is obtained by a financial institution. Most business method patents are also software patents. Have these patents increased innovation in financial services? To address this question, we construct new indicators of research and development intensity based on the occupational composition of financial industries. The financial sector appears more research intensive than official statistics would suggest but less than the private economy taken as a whole. There is considerable variation across industries but little apparent trend. There does not appear to be an obvious effect from business method patents on the sector's research intensity. Looking ahead, three factors suggest that the patent system may affect financial services as it has electronics: (1) the sector's heavy reliance on information technology, (2) the importance of standard setting, and (3) the strong network effects exhibited in many areas of finance. Even today litigation is not uncommon; we sketch a number of significant examples affecting financial exchanges and consumer payments. The legal environment is changing quickly. We review a number of important federal court decisions that will affect how business method patents are obtained and enforced. We also review a number of proposals under consideration in the U.S. Congress. (JEL O31, O34, G20) [source] Applying the Collective Causal Mapping Methodology to Operations Management Curriculum Development,DECISION SCIENCES JOURNAL OF INNOVATIVE EDUCATION, Issue 2 2007Julie M. Hays ABSTRACT Although the field of operations management has come a long way since its beginnings in scientific management, the field still appears somewhat amorphous and unstructured to many. Introductory operations management textbooks usually include a number of largely disjointed topics, which leave many students (and their instructors) without a coherent framework for understanding the field. As a result, the importance and sequencing of topics varies widely between courses and instructors, even within the same university. This article applies the newly developed Collective Causal Mapping Methodology to create a causal map for the entire field of operations management. The causal map is built on expert opinions collected from over 250 academics and practitioners representing many areas of expertise, schools, organizations, and countries. This collective causal map is then used to create a new framework for understanding and teaching operations management. This framework can aid instructors in determining which topics should be taught in an operations management course, how these topics might be grouped and sequenced, and the important interrelationships among the topics that should be stressed to students. [source] Role and therapeutic potential of microRNAs in diabetesDIABETES OBESITY & METABOLISM, Issue 2009I. G. M. Kolfschoten The discovery in mammalian cells of hundreds of small RNA molecules, called microRNAs, with the potential to modulate the expression of the majority of the protein-coding genes has revolutionized many areas of biomedical research, including the diabetes field. MicroRNAs function as translational repressors and are emerging as key regulators of most, if not all, physiological processes. Moreover, alterations in the level or function of microRNAs are associated with an increasing number of diseases. Here, we describe the mechanisms governing the biogenesis and activities of microRNAs. We present evidence for the involvement of microRNAs in diabetes mellitus, by outlining the contribution of these small RNA molecules in the control of pancreatic ,-cell functions and by reviewing recent studies reporting changes in microRNA expression in tissues isolated from diabetes animal models. MicroRNAs hold great potential as therapeutic targets. We describe the strategies developed for the delivery of molecules mimicking or blocking the function of these tiny regulators of gene expression in living animals. In addition, because changes in serum microRNA profiles have been shown to occur in association with different human diseases, we also discuss the potential use of microRNAs as blood biomarkers for prevention and management of diabetes. [source] Virtual microscopy: An educator's tool for the enhancement of cytotechnology students' locator skillsDIAGNOSTIC CYTOPATHOLOGY, Issue 6 2008Jimmie Stewart III M.D. Abstract Virtual microscopy (VM) is being utilized as an educational tool in many areas of pathology. The aim of this study is to analyze the locator and diagnostic skills of cytotechnology students by using the Aperio T3 ScanScope®, and examine VM's viability as an educational tool in cytotechnology. Ten validated cytology slides were digitized and reviewed by three senior cytotechnologist instructors. Each technologist made annotations indicating diagnostic areas on the virtual slide. A subset of the slides was used for locator skill evaluation. Cytotechnology students examined a pristine copy of the virtual slide and made annotations for comparison to those made by experienced instructors. Annotations of the subset were then scored based on the degree of correlation between students and cytotechnologists. A cytopathologist performed a final review of the students' marks; points were then added or subtracted based on this interpretation. Students were graded based on their correlation to senior cytotechnologists. A statistical analysis using modified interrater calculations ranked the students as to locator ability, producing illuminating results. This study shows that VM has promise as a cytotechnology educational tool by allowing the instructor to evaluate students' locator and diagnostic abilities. We have attempted to implement a simple scoring system for evaluation of locator skills where students are compared versus expert cytotechnologists. We anticipate further technological improvements as the products mature. Diagn. Cytopathol. 2008;36:363,368. © 2008 Wiley-Liss, Inc. [source] Conceptual Equivocation and Epistemic RelevanceDIALECTICA, Issue 2 2009Mikkel Gerken Much debate has surrounded "switching" scenarios in which a subject's reasoning is said to exhibit the fallacy of equivocation (Burge 1988; Boghossian 1992, 1994). Peter Ludlow has argued that such scenarios are "epistemically prevalent" and, therefore, epistemically relevant alternatives (Ludlow 1995a). Since a distinctive feature of the cases in question is that the subject blamelessly engages in conceptual equivocation, we may label them ,equivocational switching cases'. Ludlow's influential argument occurs in a discussion about compatibilism with regards to anti-individualism (or content externalism) and self-knowledge. However, the issue has wide-reaching consequences for many areas of epistemology. Arguably, the claim that equivocational switching cases are epistemically relevant may bear on the epistemology of inference, testimony, memory, group rationality and belief revision. Ludlow's argument proceeds from a now well-known "down to Earth" switching-case of a subject, Biff, who travels between the US and the UK. I argue that Ludlow's case-based argument fails to support the general claim that conceptual equivocational switching cases are prevalent and epistemically relevant. Thus, the discussion addresses the basis of some poorly understood issues regarding the epistemological consequences of anti-individualism. Simultaneously, the discussion is broadened from the narrow focus on self-knowledge. Finally, the critical discussion serves as the basis for some general reflections on epistemic relevance and the epistemic risks associated with conceptual equivocation. Specifically, I suggest that philosophy is an area where the risk of conceptual equivocation is extraordinarily high. [source] The causes, consequences and detection of publication bias in psychiatryACTA PSYCHIATRICA SCANDINAVICA, Issue 4 2000Simon M. Gilbody Objective: Publication bias threatens the validity of published research, although this topic has received little attention in psychiatry. The purpose of this article is to produce a systematic overview of the causes and consequences of publication bias and to summarize the available methods with which it is detected and corrected. Method: Empirical evidence for the existence of publication bias is reviewed and the following methods are applied to an illustrative case example from psychiatry: funnel plot analysis; the ,file drawer method'; linear regression techniques; rank correlation; ,trim and fill'. Results: Small studies are particularly susceptible to publication and related bias. All methods to detect publication bias depend upon the availability of a number of individual studies with a range of sample sizes. Unfortunately, large numbers of studies of varying sample size are not always available in many areas of psychiatric research. Conclusion: Where possible researchers should always test for the presence of publication bias. The problem of publication bias will not be solved by anything other than a prospective trials register. [source] Prey availability influences habitat tolerance: an explanation for the rarity of peregrine falcons in the tropicsECOGRAPHY, Issue 3 2001Andrew R. Jenkins The density and productivity of peregrine falconFalco peregrinus populations correlate positively with distance from the Equator, while habitat specificity increases with proximity to the Equator. Low peregrine densities in the tropics may he a result of competition with similar conveners (e.g. the lanner falcon F. biarmicus in Africa), which replace them in many areas. Alternatively, tropical peregrines may he limited by resource deficiencies that do not affect their close relatives. Data from peregrine and lanner populations in South Africa support the resource deficiency hypothesis, and there is no evidence to suggest direct competition between the two species. In areas where prey are not spatially or temporally concentrated, or otherwise particularly vulnerable to attack, morphological and behavioural specializations of peregrines probably restrict them to optimal foraging conditions. The relative dynamics of.Arctic and temperate vs tropical prey populations is suggested as an important factor determining peregrine distribution globally. Populations of other widespread hut particularly specialized avian predators (e.g. osprey Pandion haliaetus) may he similarly controlled. Food limitation (in terms of a dearth of particularly vulnerable prey) in the tropics has resulted in specialization and rarity in peregrines and generalization and relative abundance in similar congeners. [source] Prey availability influences habitat tolerance: an explanation for the rarity of peregrine falcons in the tropicsECOGRAPHY, Issue 3 2001Article first published online: 30 JUN 200 The density and productivity of peregrine falcon Falco peregrinus populations correlate positively with distance from the Equator, while habitat specificity increases with proximity to the Equator. Low peregrine densities in the tropics may be a result of competition with similar congeners (e.g. the lanner falcon F. biarmicus in Africa), which replace them in many areas. Alternatively, tropical peregrines may be limited by resource deficiencies that do not affect their close relatives. Data from peregrine and lanner populations in South Africa support the resource deficiency hypothesis, and there is no evidence to suggest direct competition between the two species. In areas where prey are not spatially or temporally concentrated, or otherwise particularly vulnerable to attack, morphological and behavioural specializations of peregrines probably restrict them to optimal foraging conditions. The relative dynamics of Arctic and temperate vs tropical prey populations is suggested as an important factor determining peregrine distribution globally. Populations of other widespread but particularly specialized avian predators (e.g. osprey Pandion haliaetus) may be similarly controlled. Food limitation (in terms of a dearth of particularly vulnerable prey) in the tropics has resulted in specialization and rarity in peregrines and generalization and relative abundance in similar congeners. [source] The costs and benefits of fast livingECOLOGY LETTERS, Issue 12 2009Karen E. Rose Abstract Growth rates play a fundamental role in many areas of biology (Q. Rev. Biol., 67, 1992, 283; Life History Invariants. Some Explorations of Symmetry in Evolutionary Biology, 1993; Philos. Trans. R. Soc. Lond. B Biol. Sci., 351, 1996, 1341; Plant Strategies, Vegetation Processes, and Ecosystem Properties, 2002; Trends Ecol. Evol., 18, 2003, 471; Q. Rev. Biol., 78, 2003, 23; J. Ecol., 95, 2007, 926.) but the cost and benefits of different growth rates are notoriously difficult to quantify (Q. Rev. Biol., 72, 1997, 149; Funct. Ecol., 17, 2003, 328). This is because (1) growth rate typically declines with size and yet the most widely used growth measure , relative growth rate or RGR (conventionally measured as the log of the ratio of successive sizes divided by the time interval) , is not size-corrected and so confounds growth and size, (2) organisms have access to different amounts of resource and (3) it is essential to allow for the long-term benefits of larger size. Here we experimentally demonstrate delayed costs and benefits of rapid growth in seven plant species using a novel method to calculate size-corrected RGR. In control treatments, fast-growing plants benefited from increased reproduction the following year; however, fast-growing plants subjected to an experimental stress treatment (defoliation) showed strongly reduced survival and reproduction the following year. Importantly, when growth was estimated using the classical RGR measure, no costs or benefits were found. These results support the idea that life-history trade-offs have a dominant role in life-history and ecological theory and that the widespread failure to detect them is partly due to methodological shortcomings. Ecology Letters (2009) 12: 1379,1384 [source] The ratification of ILO conventions: A hazard rate analysisECONOMICS & POLITICS, Issue 3 2001Bernhard Boockmann There are over 180 ILO conventions in many areas of labour law, industrial relations and social security, but they are not ratified universally: for the conventions adopted between 1975 and 1995, the cumulative probability of ratification is about 13 percent 10 years after their adoption. In this paper, the ratification decision is understood as a transition between two states. Using duration analysis, we identify circumstances which are favourable to this transition. For industrialized countries, the ratification of ILO conventions is shown to depend on internal political factors such as government preferences or the power of left-wing parties in parliament. For developing countries, economic costs of ratification have a significant impact. There is no evidence for external pressure in favour of ratification. Among industrialized member states, there is a clear downward trend in estimated ratification probabilities over the last two decades. [source] Indications for cell stress in response to adenoviral and baculoviral gene transfer observed by proteome profiling of human cancer cellsELECTROPHORESIS, Issue 11 2010Christopher Gerner Abstract Gene transfer to cultured cells is an important tool for functional studies in many areas of biomedical research and vector systems derived from adenoviruses and baculoviruses are frequently used for this purpose. In order to characterize how viral gene transfer vectors affect the functional state of transduced cells, we applied 2-D PAGE allowing quantitative determination of protein amounts and synthesis rates of metabolically labeled cells and shotgun proteomics. Using HepG2 human hepatoma cells we show that both vector types can achieve efficient expression of green fluorescent protein, which accounted for about 0.1% of total cellular protein synthesis 72,h after transduction. No evidence in contrast was found for expression of proteins from the viral backbones. With respect to the host cell response, both vectors induced a general increase in protein synthesis of about 50%, which was independent of green fluorescent protein expression. 2-D PAGE autoradiographs identified a 3.6-fold increase of ,-actin synthesis in adenovirus transduced cells. In addition shotgun proteomics of cytoplasmic and nuclear extract fractions identified a slight induction of several proteins related to inflammatory activation, cell survival and chromatin function by both virus types. These data demonstrate that commonly used gene transfer vectors induce a response reminiscent of stress activation in host cells, which needs to be taken into account when performing functional assays with transduced cells. [source] Ecotype diversity in the marine picoeukaryote Ostreococcus (Chlorophyta, Prasinophyceae)ENVIRONMENTAL MICROBIOLOGY, Issue 6 2005Francisco Rodríguez Summary The importance of the cyanobacteria Prochlorococcus and Synechococcus in marine ecosystems in terms of abundance and primary production can be partially explained by ecotypic differentiation. Despite the dominance of eukaryotes within photosynthetic picoplankton in many areas a similar differentiation has never been evidenced for these organisms. Here we report distinct genetic [rDNA 18S and internal transcribed spacer (ITS) sequencing], karyotypic (pulsed-field gel electrophoresis), phenotypic (pigment composition) and physiological (light-limited growth rates) traits in 12 Ostreococcus strains (Prasinophyceae) isolated from various marine environments and depths, which suggest that the concept of ecotype could also be valid for eukaryotes. Internal transcribed spacer phylogeny grouped together four deep strains isolated between 90 m and 120 m depth from different geographical origins. Three deep strains displayed larger chromosomal bands, different chromosome hybridization patterns, and an additional chlorophyll (chl) c -like pigment. Furthermore, growth rates of deep strains show severe photo-inhibition at high light intensities, while surface strains do not grow at the lowest light intensities. These features strongly suggest distinct adaptation to environmental conditions encountered at surface and the bottom of the oceanic euphotic zone, reminiscent of that described in prokaryotes. [source] The implementation of international nature conservation agreements in Europe: the case of the NetherlandsENVIRONMENTAL POLICY AND GOVERNANCE, Issue 3 2001Graham Bennett Nature conservation policy in European countries is increasingly determined by the requirements of a wide range of international agreements. The most important are two EU directives (the Birds Directive and the Habitats Directive) and four conventions (the Ramsar Convention, the Bern Convention, the Bonn Convention and the UN Convention on Biological Diversity). The main foci of these instruments are habitats and species that are of international importance or require international cooperation to secure their effective conservation. Despite the importance of these habitats and species, implementation of the instruments has been uneven. The Netherlands provides a interesting example of implementation issues. The legislation necessary to enable the government to legally designate areas that have to be protected under the Birds Directive was only adopted in 1998, 17 years after the deadline fixed by the directive. This legislation has enabled the government to nominate areas for designation under the Birds and Habitats Directive. However, not all the sites that fall under the criteria of the Directives have been included in the list, and the legislation does not include the required provision concerning compensation for areas that are protected under the Habitats Directive and then damaged by activities that are authorized in the public interest. In the case of the Ramsar Convention, the government is planning to increase the number of designated sites, but the total number of sites will still represent inadequately the types of wetland of international importance that are found in the Netherlands. Despite this uneven implementation, the instruments , particularly the EU Directives , are having far-reaching effects on nature conservation in Europe. The most important consequences are that ecological considerations are the sole and absolute criteria for determining whether a site should be protected under the EU Directives and that many areas that until now only enjoyed limited protection under the spatial planning system now have to be legally protected from virtually all forms of damage. However, in practice many development plans take only limited account of the biodiversity conservation requirements implied by international conventions. Copyright © 2001 John Wiley & Sons, Ltd. and ERP Environment [source] Clinical features associated with medically unexplained stroke-like symptoms presenting to an acute stroke unitEUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2005F. S. Nazir In many areas of secondary care, symptoms unexplained by disease account for around one-third of all patients seen. We sought to investigate patients presenting with medically unexplained stroke-like symptoms to identify distinguishing features which may help to identify a non-organic aetiology. Patients given a discharge diagnosis of medically unexplained stroke-like symptoms over the preceding 11 years were identified retrospectively from a prospectively completed stroke unit database. Age- and sex-matched controls with ischaemic or haemorrhagic stroke or transient ischaemic attack were also identified. Clinical features on presentation, ischaemic risk factors, alcohol history, marital status and history of depression or anxiety were examined. Previous or subsequent admissions with medically unexplained syndromes were also examined via record linkage with hospital discharge records. A medically unexplained syndrome was assumed to be present if an International Classification of Diseases 9 discharge code for one or more of the thirteen conditions forming recognized functional syndromes was given. Logistic regression was applied to determine predictors of non-organicity. One hundred and five patients and controls, 1.6% of all stroke unit admissions were identified, 62% (65 patients) were females. Mean age was 50.3 ± 14.9. Compared with age- and sex-matched controls patients with medically unexplained stroke-like symptoms were significantly more probable to have a headache at presentation (47% vs. 26%, P = 0.0004), have a diagnosis of one or more additional medically unexplained syndromes (24% vs. 11%, P = 0.007) but significantly less probable to present with symptoms of vertebrobasilar dysfunction (32% vs. 61%, P < 0.0001). A history of anxiety or depression, as recorded in the notes, was not found to be associated with a medically unexplained presentation. Medically unexplained stroke-like presentations are common (1.6% of all stroke presentations), they are most strongly predicted by the presence of other functional somatic syndromes, headache and the absence of symptoms of vertebrobasilar dysfunction. [source] TESTING THE ROLE OF INTERSPECIFIC COMPETITION IN THE EVOLUTIONARY ORIGIN OF ELEVATIONAL ZONATION: AN EXAMPLE WITH BUARREMON BRUSH-FINCHES (AVES, EMBERIZIDAE) IN THE NEOTROPICAL MOUNTAINSEVOLUTION, Issue 5 2007Carlos Daniel Cadena Interspecific competition might drive the evolution of ecological niches and result in pairs of formerly competing species segregating along ecological gradients following a process of character displacement. This mechanism has been proposed to account for replacement of related species along gradients of elevation in many areas of the world, but the fundamental issue of whether competition is responsible for the origin of elevational replacements has not been tested. To test hypotheses about the role of interspecific competition in the origin of complementary elevational ranges, I combined molecular phylogenetics, phylogeography, and population genetic analyses on Buarremon torquatus and B. brunneinucha (Aves, Emberizidae), whose patterns of elevational distribution suggest character displacement or ecological release. The hypothesis that elevational distributions in these species changed in opposite directions as a result of competition is untenable because: (1) a historical expansion of the range of B. brunneinucha into areas occupied by B. torquatus was not accompanied by a shift in the elevational range of the former species; (2) when B. brunneinucha colonized the range of B. torquatus, lineages of the latter distributions had already diverged; and (3) historical trends in effective population size do not suggest populations with elevational ranges abutting those of putative competitors have declined as would be expected if competition caused range contractions. However, owing to uncertainty in coalescent estimates of historical population sizes, the hypothesis that some populations of B. torquatus have declined cannot be confidently rejected, which suggests asymmetric character displacement might have occurred. I suggest that the main role of competition in elevational zonation may be to act as a sorting mechanism that allows the coexistence along mountain slopes only of ecologically similar species that differ in elevational distributions prior to attaining sympatry. The contrasting biogeographic histories of B. brunneinucha and B. torquatus illustrate how present-day ecological interactions can have recent origins, and highlights important challenges for testing the hypothesis of character displacement in the absence of data on population history and robust reconstructions of the evolution of traits and geographic ranges. [source] How best to fight that nasty itch , from new insights into the neuroimmunological, neuroendocrine, and neurophysiological bases of pruritus to novel therapeutic approachesEXPERIMENTAL DERMATOLOGY, Issue 3 2005T. Biró While the enormous clinical and psychosocial importance of pruritus in many areas of medicine and the detrimental effects of chronic ,itch' on the quality of life of an affected individual are widely appreciated, the complexity of this sensation is still often grossly underestimated. The current Controversies feature highlights this complexity by portraying pruritus as a truly interdisciplinary problem at the crossroads of neurophysiology, neuroimmunology, neuropharmacology, protease research, internal medicine, and dermatology, which is combated most successfully if one keeps the multilayered nature of ,itch' in mind and adopts a holistic treatment approach , beyond the customary, frequently frustrane monotherapy with histamine receptor antagonists. In view of the often unsatisfactory, unidimensional, and altogether rather crude standard instruments for pruritus management that we still tend to use in clinical practice today, an interdisciplinary team of pruritus experts here critically examines recent progress in pruritus research that future itch management must take into consideration. Focusing on new insights into the neuroimmunological, neuroendocrine, and neurophysiological bases of pruritus, and discussing available neuropharmacological tools, specific research avenues are highlighted, whose pursuit promises to lead to novel, and hopefully more effective, forms of pruritus management. [source] Effects of cryptic mortality and the hidden costs of using length limits in fishery managementFISH AND FISHERIES, Issue 3 2007Lewis G Coggins Jr Abstract Fishery collapses cause substantial economic and ecological harm, but common management actions often fail to prevent overfishing. Minimum length limits are perhaps the most common fishing regulation used in both commercial and recreational fisheries, but their conservation benefits can be influenced by discard mortality of fish caught and released below the legal length. We constructed a computer model to evaluate how discard mortality could influence the conservation utility of minimum length regulations. We evaluated policy performance across two disparate fish life-history types: short-lived high-productivity (SLHP) and long-lived low-productivity (LLLP) species. For the life-history types, fishing mortality rates and minimum length limits that we examined, length limits alone generally failed to achieve sustainability when discard mortality rate exceeded about 0.2 for SLHP species and 0.05 for LLLP species. At these levels of discard mortality, reductions in overall fishing mortality (e.g. lower fishing effort) were required to prevent recruitment overfishing if fishing mortality was high. Similarly, relatively low discard mortality rates (>0.05) rendered maximum yield unobtainable and caused a substantial shift in the shape of the yield response surfaces. An analysis of fishery efficiency showed that length limits caused the simulated fisheries to be much less efficient, potentially exposing the target species and ecosystem to increased negative effects of the fishing process. Our findings suggest that for overexploited fisheries with moderate-to-high discard mortality rates, reductions in fishing mortality will be required to meet management goals. Resource managers should carefully consider impacts of cryptic mortality sources (e.g. discard mortality) on fishery sustainability, especially in recreational fisheries where release rates are high and effort is increasing in many areas of the world. [source] Trouble on the reef: the imperative for managing vulnerable and valuable fisheriesFISH AND FISHERIES, Issue 3 2005Yvonne Sadovy Abstract Reef fishes are significant socially, nutritionally and economically, yet biologically they are vulnerable to both over-exploitation and degradation of their habitat. Their importance in the tropics for living conditions, human health, food security and economic development is enormous, with millions of people and hundreds of thousands of communities directly dependent, and many more indirectly so. Reef fish fisheries are also critical safety valves in times of economic or social hardship or disturbance, and are more efficient, less wasteful and support far more livelihoods per tonne produced than industrial scale fisheries. Yet, relative to other fisheries globally, those associated with coral reefs are under-managed, under-funded, under-monitored, and as a consequence, poorly understood or little regarded by national governments. Even among non-governmental organizations, which are increasingly active in tropical marine issues, there is typically little focus on reef-associated resources, the interest being more on biodiversity per se or protection of coral reef habitat. This essay explores the background and history to this situation, examines fishery trends over the last 30 years, and charts a possible way forward given the current realities of funding, capacity, development patterns and scientific understanding of coral reef ecosystems. The luxury live reef food-fish trade is used throughout as a case study because it exemplifies many of the problems and challenges of attaining sustainable use of coral reef-associated resources. The thesis developed is that sustaining reef fish fisheries and conserving biodiversity can be complementary, rather than contradictory, in terms of yield from reef systems. I identify changes in perspectives needed to move forward, suggest that we must be cautious of ,fashionable' solutions or apparent ,quick fixes', and argue that fundamental decisions must be made concerning the short and long-term values of coral reef-associated resources, particularly fish, for food and cash and regarding alternative sources of protein. Not to address the problems will inevitably lead to growing poverty, hardship and social unrest in many areas. [source] Organic Ligands Made Porous: Magnetic and Catalytic Properties of Transition Metals Coordinated to the Surfaces of Mesoporous OrganosilicaADVANCED FUNCTIONAL MATERIALS, Issue 7 2010Andreas Kuschel Abstract Inorganic solids with porosity on the mesoscale possess a high internal surface area and a well-accessible pore system. Therefore, it is a relevant task to equip the surfaces of such materials with a maximum density of various organic functional groups. Among these functions it is the capability of coordinating to metal species as a ligand that is of extraordinary importance in many areas, for example, in catalysis. This paper describes how prominent ligands containing donor functions such as carboxylic, thio, chelating, or amine groups can be obtained in the form of nanoporous organosilica materials. The coordination of metal centers such as CoII, MnII, VIV, or PtIV is studied in detail. The magnetic properties of the corresponding materials and some applications in catalysis are reported. A quantitative determination of the surface density of donor atoms by distance measurements using EPR spectroscopy is shown. [source] Surface Plasmonics: Plasmonic Crystals: A Platform to Catalog Resonances from Ultraviolet to Near-Infrared Wavelengths in a Plasmonic Library (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 4 2010Mater. Research in the field of surface plasmonics is finding application in many areas; for example, in data storage, nano-electronics, and biosensing. In their feature article on page 529, H. Gao et al. describe recent progress in manipulating surface plasmons from the ultraviolet to near-infrared wavelengths using nanostructured plasmonic crystals (shown in the cover image), and build a comprehensive library of plasmonic resonances, bringing together for the first time the resonance characteristics of key plasmonic materials. [source] A Computational Framework for Patient-Specific Analysis of Articular Cartilage Incorporating Structural Information from DT-MRIGAMM - MITTEILUNGEN, Issue 2 2009David M. Pierce Abstract Accurate techniques for simulating sof t biological tissue deformation are an increasingly valuable tool in many areas of biomechanical analysis and medical image computing. To model the morphology and the material response of human articular cartilage a phenomenological and patient-specific simulation approach incorporating the collagen fibre fabric is proposed. We then demonstrate a unique combination of ultra-high field Diffusion Tensor Magnetic Resonance Imaging (17.6T DT-MRI) and a novel numerical approach incorporating the empirical data to predict the collagen fibre fabric deformation for an indentation experiment (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] New perspectives on Holocene landscape development in the southern English chalklands: The upper Allen valley, Cranborne Chase, DorsetGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 2 2005C. French A combination of on- and off-site paleoenvironmental and archaeological investigations of the upper Allen valley of Dorset, conducted from 1998,2002, has begun to indicate a different model of prehistoric landscape development to those previously put forward for this part of the southern English chalk downlands. Woodland growth in the earlier Holocene appears to have been slower and patchier than the presumed model of full climax deciduous woodland rapidly attained in a warming environment. With open areas still strongly present in the Mesolithic, the area witnessed its first exploitation, thus slowing and altering soil development. Consequently, many areas perhaps never developed thick, well-structured, brown forest earths, but more probably thin brown earths. By the later Neolithic period, these soils had become thin rendzinas, largely as a consequence of human exploitation and the predominance of pastoral land use. The early presence of thinner and less well-developed soils over large areas of downland removes the necessity for envisaging extensive soil erosion and the accumulation of thick colluvial and alluvial deposits in the dry valleys and valley floor as often postulated. If there were major changes in the vegetation and soil complexes in this area of chalk downland, these had already occurred by the Neolithic rather than the Bronze Age as often suggested, and the area has remained relatively stable ever since. This has major implications for models of prehistoric land use in the southern chalkland region, such as a much greater degree of stability in prehistoric and historic times, variability within sub-regions, and differences between different parts of the chalk downlands than had previously been envisaged. © 2005 Wiley Periodicals, Inc. [source] GIS Methods in Time-Geographic Research: Geocomputation and Geovisualization of Human Activity PatternsGEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 4 2004Mei-Po Kwan Abstract Over the past 40 years or so, human activities and movements in space-time have attracted considerable research interest in geography. One of the earliest analytical perspectives for the analysis of human activity patterns and movements in space-time is time geography. Despite the usefulness of time geography in many areas of geographical research, there are very few studies that actually implemented its constructs as analytical methods up to the mid-1990s. With increasing availability of geo-referenced individual-level data and improvement in the geo-computational capabilities of Geographical Information Systems (GIS), it is now more feasible than ever before to operationalize and implement time-geographic constructs. This paper discusses recent applications of GIS-based geo-computation and three-dimensional (3-D) geo-visualization methods in time-geographic research. The usefulness of these methods is illustrated through examples drawn from the author's recent studies. The paper attempts to show that GIS provides an effective environment for implementing time-geographic constructs and for the future development of operational methods in time-geographic research. [source] Enigmatic sedimentary,volcanic successions in the central European Variscides: a Cambrian/Early Ordovician age for the Wojcieszów Limestone (Kaczawa Mountains, SW Poland) indicated by SHRIMP dating of volcanic zirconsGEOLOGICAL JOURNAL, Issue 4 2008Ryszard Kryza Abstract Metamorphosed volcanic and sedimentary successions in the central European Variscides are, in many areas, poorly biostratigraphically constrained, making palaeotectonic interpretations uncertain. In such instances, geochronological data are crucial. Sensitive high resolution ion microprobe (SHRIMP) dating of volcanic zircons from a quartz,white mica schist (interpreted as deformed metavolcaniclastic/epiclastic rock) within the stratigraphically controversial Wojcieszów Limestone of the Kaczawa Mountains (Sudetes, SW Poland), near to the eastern termination of the European Variscides, has yielded an age of 498,±,5,Ma (2, error), corresponding to late Cambrian to early Ordovician magmatism in that area and constraining the depositional age of the limestones. The new SHRIMP data are not consistent with the recent revision of the age of the Wojcieszów Limestone based on Foraminifera findings that ascribed them to a Late Ordovician,Silurian or even younger interval. They are though, consistent with sparse macrofossil data and strongly support earlier interpretations of the lower part of the Kaczawa Mountains succession as a Cambrian,Early Ordovician extensional basin-fill with associated initial rift volcanic rocks, likely emplaced during the breakup of Gondwana. Copyright © 2008 John Wiley & Sons, Ltd. [source] From clergymen to computers,the advent of virtual palaeontologyGEOLOGY TODAY, Issue 3 2010Russell J. Garwood Palaeontology was established as a science in the Victorian era, yet has roots that stretch deeper into the recesses of history. More than 2000 years ago, the Greek philosopher Aristotle deduced that fossil sea shells were once living organisms, and around 500 ad Xenophanes used fossils to argue that many areas of land must have previously been submarine. In 1027, the Persian scholar Avicenna suggested that organisms were fossilized by petrifying fluids; this theory was accepted by most natural philosophers up until the eighteenth century Enlightenment, and even beyond. The late 1700s were notable for the work of Georges Cuvier who established the reality of extinction. This, coupled with advances in the recognition of faunal successions made by the canal engineer William Smith, laid the framework for the discipline that would become known as palaeontology. As the nineteenth century progressed, the scientific community became increasingly well organized. Most fossil workers were gentleman scientists and members of the clergy, who self-funded their studies in a new and exciting field. Many of the techniques used to study fossils today were developed during this ,classical' period. Perhaps the most fundamental of these is to expose a fossil by splitting the rock housing it, and then conduct investigations based upon the exposed surface (Fig. 1). This approach has served the science well in the last two centuries, having been pivotal to innumerable advances in our understanding of the history of life. Nevertheless, there are many cases where splitting a rock in this way results in incomplete data recovery; those where the fossils are not flattened, but are preserved in three-dimensions. Even the ephemeral soft-tissues of organisms are occasionally preserved in a three-dimensional state, for example in the Herefordshire, La Voulte Sűr Rhone and Orsten ,Fossil Lagerstätten' (sites of exceptional fossil preservation). These rare and precious deposits provide a wealth of information about the history of life on Earth, and are perhaps our most important resource in the quest to understand the palaeobiology of extinct organisms. With the aid of twenty-first century technology, we can now make the most of these opportunities through the field of ,virtual palaeontology',computer-aided visualization of fossils. Figure 1. A split nodule showing the fossil within, in this case a cockroachoid insect. Fossil 4 cm long (From Garwood & Sutton, in press). [source] Self-Organized Single-Walled Carbon Nanotube Conducting Thin Films with Honeycomb Structures on Flexible Plastic FilmsADVANCED FUNCTIONAL MATERIALS, Issue 2 2009Nobuo Wakamatsu Abstract Complex 1, synthesized from anionic shortened single-walled carbon nanotubes and cationic ammonium lipid dissolved in organic solvents, is cast on pretreated transparent flexible poly(ethylene terephthalate) (PET) films under a higher relative humidity to form thin films with self-organized honeycomb structures. The cell sizes are controllable by changing the experimental conditions. The lipid, which is the cationic part of complex 1, is easily removed by a simple ion-exchange method, while maintaining the basic honeycomb structures. After the ion exchange, the nanotube honeycomb films on PET with thinner skeletons exhibit a dramatic decrease in the surface resistivity from insulating to conducting. Carbon nanotubes with honeycomb structures formed by the self-organization on flexible polymer films are useful in many areas of nanoscience and technology including nanomaterials, nanoelectronics, nanodevices, catalysts, sensors, and so on. [source] | |||||||||||||||||||||||||||||||||||||||||||