Home About us Contact
|
Home About us Contact | ||
|
|
||
Clear Picture (clear + picture)
Selected AbstractsThe Contribution of Long-Term Research at Gombe National Park to Chimpanzee ConservationCONSERVATION BIOLOGY, Issue 3 2007ANNE E. PUSEY chimpancé; conservación de simios mayores; Parque Nacional Gombe; Tanzania Abstract:,Long-term research projects can provide important conservation benefits, not only through research specifically focused on conservation problems, but also from various incidental benefits, such as increased intensity of monitoring and building support for the protection of an area. At Gombe National Park, Tanzania, long-term research has provided at least four distinct benefits to wildlife conservation. (1) Jane Goodall's groundbreaking discoveries of chimpanzee (Pan troglodytes) tool use, hunting, and complex social relationships in what was then a game reserve drew attention to the area and created support for upgrading Gombe to national park status in 1968. (2) The highly publicized findings have earned Gombe and Tanzania the attention of a worldwide public that includes tourists and donors that provide financial support for Gombe, other parks in Tanzania, and chimpanzee conservation in general. (3) Crucial information on social structure and habitat use has been gathered that is essential for effective conservation of chimpanzees at Gombe and elsewhere. (4) A clear picture of Gombe's chimpanzee population over the past 40 years has been determined, and this has helped identify the greatest threats to the viability of this population, namely disease and habita loss outside the park. These threats are severe and because of the small size of the population it is extremely vulnerable. Research at Gombe has led to the establishment of conservation education and development projects around Gombe, which are needed to build local support for the park and its chimpanzees, but saving these famous chimpanzees will take a larger integrated effort on the part of park managers, researchers, and the local community with financial help from international donors. Resumen:,Los proyectos de investigación de largo plazo pueden proporcionar beneficios importantes a la conservación, no solo a través de investigación enfocada específicamente a problemas de conservación, sino también a través de varios beneficios incidentales, como una mayor intensidad de monitoreo y construcción de soporte para la protección de un área. En el Parque Nacional Gombe, Tanzania, la investigación a largo plazo ha proporcionado por lo menos cuatro beneficios a la conservación de vida silvestre. (1) Los descubrimientos innovadores de Jane Goodall sobre el uso de herramientas, la cacería y las complejas relaciones sociales de chimpancés en lo que entonces era una reserva de caza atrajeron la atención al área y crearon el soporte para cambiar a Gombe a estatus de parque nacional en 1968. (2) Los hallazgos muy publicitados han ganado para Gombe y Tanzania la atención del público en todo el mundo incluyendo turistas y donadores que proporcionan soporte financiero a Gombe, otros parques en Tanzania y a la conservación de chimpancés en general. (3) Se ha reunido información crucial sobre la estructura social y el uso del hábitat que ha sido esencial para la conservación efectiva de chimpancés en Gombe y otros sitios. (4) Se ha determinado un panorama claro de la población de chimpancés en Gombe durante los últimos 40 años, y esto a ayudado a identificar las mayores amenazas a la viabilidad de esta población, a saber enfermedades y pérdida de hábitat fuera del parque. Estas amenazas son severas y la población es extremadamente vulnerable por su tamaño pequeño. La investigación en Gombe ha llevado al establecimiento de proyectos de desarrollo y de educación para la conservación en los alrededores del parque, lo cual es necesario para encontrar soporte local para el parque y sus chimpancés, pero el rescate de estos famosos chimpancés requerirá de un esfuerzo más integrado de parte de los manejadores del parque, investigadores y la comunidad local con la ayuda financiera de donadores internacionales. [source] Density-dependent dispersal in birds and mammalsECOGRAPHY, Issue 3 2005Erik Matthysen Density-dependent dispersal can be caused by various mechanisms, from competition inducing individuals to emigrate (positive density-dependence) to social crowding effects impeding free movement (negative density-dependence). Various spatial population models have incorporated positively density-dependent dispersal algorithms, and recent theoretical models have explored the conditions for density-dependent dispersal (DD) to evolve. However, while the existence of DD is well documented in some taxa such as insects, there is no clear picture on its generality in vertebrates. Here I review the available empirical data on DD in birds and mammals, focusing mainly on variation in dispersal between years and on experimental density manipulations. Surprisingly few studies have explicitly focused on DD, and interpretation of the available data is often hampered by differences in approach, small sample sizes and/or statistical shortcomings. Positive DD was reported in 50 and 33% of the selected mammal and bird studies, respectively, while two studies on mammals (out of eight) reported negative DD. Among bird studies, DD was more often reported for emigration rates or long-distance recoveries than for average distances within finite study areas. Experimental studies manipulating densities (mainly on mammals) have consistently generated positive DD, typically showing reduced emigration in response to partial population removal. Studies that examined dispersal in relation to seasonal changes in density (small mammals only) have more often reported negative DD. Studies that compared dispersal between sites differing in density, also show a mixture of positive and negative DD. This suggests that dispersal changes in a more complex way with seasonal and spatial density variation than with annual densities, and/or that these results are confounded by other factors differing between seasons and sites, such as habitat quality. I conclude that both correlational and experimental studies support the existence of positive, rather than negative, density-dependent dispersal in birds and mammals. [source] High Quality Factor Metallodielectric Hybrid Plasmonic,Photonic CrystalsADVANCED FUNCTIONAL MATERIALS, Issue 12 2010Xindi Yu Abstract A 2D polystyrene colloidal crystal self-assembled on a flat gold surface supports multiple photonic and plasmonic propagating resonance modes. For both classes of modes, the quality factors can exceed 100, higher than the quality factor of surface plasmons (SP) at a polymer,gold interface. The spatial energy distribution of those resonance modes are carefully studied by measuring the optical response of the hybrid plasmonic,photonic crystal after coating with dielectric materials under different coating profiles. Computer simulations with results closely matching those of experiments provide a clear picture of the field distribution of each resonance mode. For the SP modes, there is strong confinement of electromagnetic energy near the metal surface, while for optical modes, the field is confined inside the spherical particles, far away from the metal. Coating of dielectric material on the crystal results in a large shift in optical features. A surface sensor based on the hybrid plasmonic,photonic crystal is proposed, and it is shown to have atomic layer sensitivity. An example of ethanol vapor sensing based on physisorption of ethanol onto the sensor surface is demonstrated. [source] Perceiving Rogue States: The Use of the "Rogue State" Concept by U.S. Foreign Policy ElitesFOREIGN POLICY ANALYSIS, Issue 4 2007K. P. O'Reilly In the aftermath of the Cold War, U.S. foreign policy dialogue has shifted from its half century focus dominated by the superpower struggle with the Soviet Union to the challenges presented by so-called "rogue states." For many observers, however, the term "rogue state" is viewed as problematic failing to providing either a clear picture of who and what constitutes a rogues state, or, perhaps more importantly, the ramification of this term on U.S. policy action. In examining the public statements of key U.S. foreign policy decision makers over the course of 1993 to 2004, this paper offers insights as to the perceptions which manifest the "rogue" stereotype as exhibited by statements on the policies and behaviors associated with rogue states. What is revealed is a relatively fixed and stable image over time as held by key decisions-makers with similar unity expressed as to policy prescriptions. Combining perceptions of power capabilities and cultural judgments unique to this rogue stereotype, the rogue image presents a challenge to U.S. strategy demanding attention to the future threat posed by these states while also constraining policy options. [source] X-ray diffraction analysis of GaInNAs double-quantum-well structuresJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2004Kiichi Nakashima The structures of GaInNAs/GaAs double-quantum-well (DQW) samples with various well-layer thicknesses were analysed by X-ray diffraction measurements. Two types of rocking-curve analysis were applied with different scanning configurations: a conventional configuration without a receiving slit and one with an analyser crystal placed in front of the receiving detector (the latter is the same as that usually used in reciprocal-space mapping measurements). It was found that systematic combination of both types of analysis is essential for the characterization of the sample structures. The two types of X-ray profiles obtained using the different scanning configurations exhibit a considerable difference in intensity as the thickness of the well layers increases. The increasing difference clearly indicates deterioration of the DQW structures. The two profiles exhibit little difference in terms of shape, merely showing that the DQW layers are coherently strained relative to the substrate. This implies that measurement in only one of the configurations is insensitive to the deterioration and leads to the wrong conclusion that a sample has a perfect structure without dislocations and defects. Photoluminescence and transmission electron microscope analyses both reveal that defects really do exist in the DQW structures, which is consistent with the difference in intensity observed in the X-ray measurements. From these results, a clear picture that consistently explains the sensitivity of X-ray diffraction analysis to the deterioration of samples is presented. In addition, based on this picture, it is proposed that the procedure of comparing the two types of profiles represents a new type of analysis method for the precise characterization of samples. [source] Is Leptin the Link Between Fat and Bone Mass?,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2002Thierry Thomas Ph.D. Abstract Recently, leptin has emerged as a potential candidate responsible for protective effects of fat on bone tissue. However, it remains difficult to draw a clear picture of leptin effects on bone metabolism because published data are sometimes conflicting or apparently contradictory. Beyond differences in models or experimental procedures, it is tempting to hypothesize that leptin exerts dual effects depending on bone tissue, skeletal maturity, and/or signaling pathway. Early in life, leptin could stimulate bone growth and bone size through direct angiogenic and osteogenic effects on stromal precursor cells. Later, it may decrease bone remodeling in the mature skeleton, when trabecular bone turnover is high, by stimulating osteoprotegerin (OPG) expression. Leptin negative effects on bone formation effected through central nervous system pathway could counterbalance these peripheral and positive effects, the latter being predominant when the blood-brain barrier permeability decreases or the serum leptin level rises above a certain threshold. Thus, the sex-dependent specificity of the relationship between leptin and bone mineral density (BMD) in human studies could be, at least in part, caused by serum leptin levels that are two- to threefold higher in women than in men, independent of adiposity. Although these hypotheses remain highly speculative and require further investigations, existing studies consistently support the role of leptin as a link between fat and bone. [source] The characteristics, qualities and skills of practice developersJOURNAL OF CLINICAL NURSING, Issue 3 2003Brendan Mccormack BSc, DPhil, PGCEA Summary ,,There is a growing interest in practice development as a systematic process for the development of quality patient care. ,,Whilst there is a range of accounts of practice development in the literature, little work has been undertaken to develop an understanding of the systems and processes involved and there is even less on the roles involved in practice development. ,,This paper explores in particular the characteristics, qualities and skills of practice developers, i.e. professionals who have formal responsibility for developing practice in organizations. ,,The paper represents part of a larger study exploring the conceptual basis of the term ,practice development'. ,,Data for this part of the project were collected through literature analysis, seven focus groups involving 60 practice developers and telephone interviews with 25 practising nurses with experience of working with practice developers. The data were analysed using cognitive mapping processes. ,,Four role functions are presented in the paper, as well as qualities and skills needed to operationalize the identified role functions. ,,A clear picture of the skills and qualities required by practice developers emerges from the data. [source] Original brands and counterfeit brands,do they have anything in common?JOURNAL OF CONSUMER BEHAVIOUR, Issue 2 2008Elfriede Penz Consumer decisions to purchase fakes instead of originals has developed into a major concern for brand manufacturers worldwide. This research looks at the customers' understanding of the key concepts "original brand" and "counterfeit brand." Using the theory of social representations helped to gain rich insight into the consumers' perception of counterfeit brands in the light of their counterpart original brands, to determine the main differences and similarities, and to identify core aspects and relative evaluations of these two concepts. Taken collectively, the results indicate that, based on single associations, respondents' mental maps of the two concepts do not overlap. It seems that they have a clear picture of what they get with the purchase of original brands versus counterfeits. Although similar attributes to evaluate "original brand" and "counterfeit brand" were used (quality and price), they contribute differently to the nature of the concepts. The benefits of both categories are strongly related to consumers' norms prevalent in their social environment. Copyright © 2008 John Wiley & Sons, Ltd. [source] Financial audits: Taking an operational viewJOURNAL OF CORPORATE ACCOUNTING & FINANCE, Issue 4 2007Rob Reider It's not just accounting for the numbers. It's accounting for the functions and activities that produce the numbers. That's why simply doing a financial audit may not give you a clear picture of the company's operations. © 2007 Wiley Periodicals, Inc. [source] The validation of a rating scale to assess dietitians' use of behaviour change skillsJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 4 2008G. Bonner Background:, Evidence suggests that education alone is unlikely to elicit dietary-behavioural change (Contento, 1995). Consequently, many dietitians are moving from a traditional advice-giving role to one which utilises ,behaviour change skills' (BCS) in dietary counselling. BCS is an umbrella term used to cover a wide range of skills and techniques drawn from the fields of counselling, motivational interviewing (MI) and cognitive behavioural therapy (CBT). In order to assess the efficacy of this approach, a means of quantifying BCS-use is required. This two-stage study aimed to validate a newly-devised scale to assess dietitians' BCS-use in one-to-one dietary counselling. Methods:, Items for the scale were generated by drawing on the literature, syllabi for training in BCS and its parent disciplines (counselling, MI and CBT), and specialist dietitians. The resulting scale and manual were revised following assessment of content validity by expert panel and piloting. In stage one, 21 dietetic consultations were audiotaped and rated for BCS-use by three BCS-trained dietitians. Inter-rater agreement was calculated using the kappa statistic and intra-class correlation (ICC), to give a ,chance corrected' measure of agreement. Validity was tested using a psychologist's subjective assessment of BCS-use as a proxy ,gold-standard' compared with the dietitians' ratings, again using kappa and ICC. In stage two the scale was further revised before an additional 20 audiotaped consultations were analysed using the same procedure. Ethical approval for the study was given by the appropriate NHS and university research ethics committees. Results:, At stage one, although kappas were fairly poor for agreement on individual criteria, the ICC for overall scores indicated a ,fair' level of agreement, according to Shrout's (1998) classifications: ICC = 0.584 (CI 0.339,0.784). Results for validity were poor with the psychologist frequently rating higher than the dietitians. At stage two, following scale revision, results for inter-rater agreement improved with more criteria showing ,moderate' or ,substantial' agreement. Ten out of the 21 criteria achieved levels of agreement classified as ,fair' or higher for all three rater pairs. The ICC for overall scores improved to indicate ,moderate' agreement: ICC = 0.640 (CI 0.404,0.821). Validity results remained poor. Discussion:, The moderate level of overall inter-rater agreement observed in the revised scale is considered acceptable (Jones, 2006) and indicates this tool is useful. This measure is more relevant to the purpose of the tool than agreement on individual criteria given it is intended to classify consultations overall as low/medium/high use of BCS rather than to examine individual skills. However, in terms of validity, the discrepancy between dietitian and psychologist ratings requires further investigation. It is hypothesized that the dietitians had higher expectations of what a dietitian could achieve in terms of proficiency in BCS and, as such, rated more stringently than the psychologist. Achieving a clear picture of validity usually necessitates a series of assessments (Murphy & Davidshofer, 2005); the BCS rating scale is no exception with further testing required. Conclusions:, The revised scale shows acceptable inter-rater reliability and robust content validity in our study sample. However, quantitative examination of validity gave poor results and further assessment is required to provide a tool with which we can confidently assess dietitians' use of BCS. References, Contento, I., Balch, G.I., Bronner, Y.L. et al. (1995) The effectiveness of nutrition education and implications for nutrition education policy, programs, and research: a review of the research. J. Nutr. Educ.27, 355,364. Jones, J.M. (2006) Nutritional Screening and Assessment Tools. New York: Nova Science Publishers. Murphy, K.R. & Davidshofer, C.O. (2005) Psychological Testing , Principles and Applications, 6th edn. New Jersey: Pearson Education Inc. Shrout, P. (1998) Measurement reliability and agreement in psychiatry. Stat. Methods Med. Res. 7, 301,317. [source] Water Consumption Based on a Disaggregated Social Accounting Matrix of Huesca (Spain)JOURNAL OF INDUSTRIAL ECOLOGY, Issue 3 2010Ignacio Cazcarro Summary Making use of the social accounting matrix (SAM) of the Spanish province of Huesca in 2002, updated following Junius and Oosterhaven's GRAS method and work by Lenzen and colleagues, we have estimated the water footprint of the region. The water footprint is defined as the volume of water needed for the production of the goods and services consumed by the inhabitants plus the direct consumption in the households. We built an open Leontief model, which gives us the water embodied in the production of goods. The valuations concern the industrial, service, and domestic sectors' water consumption, the embodied water imported from and exported to other countries, and the agrarian water use. This agrarian sector, clearly the sector that shows the greatest water consumption, is carefully examined, so it is disaggregated for the calculations into 31 irrigation land products, dry land, and 9 livestock classifications. As a consequence, the framework enables the observation of the relationships and flows of water taking place among all the sectors and activities in the economy. Finally, we also make use of the per capita water footprint estimations to get a clear picture of how the responsibility for water use is distributed once foreign trade is taken into account. [source] Skills under threat: the case of HIV/AIDS in the mining industry in ZimbabweJOURNAL OF INTERNATIONAL DEVELOPMENT, Issue 5 2006Caroline N. Matangi Abstract The Zimbabwe mining industry is currently battling to arrest further spread of the HIV/AIDS crisis in workplaces, especially its impact on labour productivity. Labour in the closed community of mines has been greatly susceptible to HIV/AIDS infection. The current AIDS incidence in the mine sites is estimated at a weighted average of 15,per,cent amongst miners, with the largest category of workers,the 30,39 years age group,also constituting the worst affected category. Given the current state of the country's economy and consequently its adverse impact on the lifestyle of miners, the pandemic is expected to increase. This paper builds on the work of the ILO (1995) involving a survey of 18 various firms/institutions. The survey was carried out in Zambia in order to assess the impact of HIV/AIDS on the productive labour force. The survey revealed that many of the firms are experiencing irregular work attendance, ,wasted' training as some of the trained workers are constantly ill or die, high medical bills, funeral costs and reduced productivity and profits. An analysis of data on the main causes of death in 1993 shows that at least 61.8,per,cent of deaths could be attributed to causes that are very closely related to HIV/AIDS complications. Based on points highlighted by respondents and analysis of symptoms suffered, it was observed that HIV/AIDS tended to affect most general workers (36.8,per,cent), followed by the lower management (30.9,per,cent) and the middle management (20.6,per,cent). Comparatively, 11.8,per,cent of the deaths in 1993 belonged to the top management. Although it is hard to appreciate the meaning of the figures without knowledge of the number of people in each category, it nevertheless helps to form a clear picture of the impact of HIV/AIDS on industry. This paper seeks to further investigate the impact of HIV/AIDS on the productive labour force, by focusing on one particular industry,mining,using a blend of research methods to collect the data. This paper examines the impact of HIV/AIDS on the productive labour force and management responses. It forms part of the findings of data gathered in 2001 in the mining industry in Zimbabwe, to examine factors affecting management responses to HIV/AIDS in the mine sites. Zimbabwe is a country with a complex historical legacy of mine labour. This phenomenon can largely be attributed to the production oriented nature of the mining industry. Mines focus mainly on mineral extraction and as a result the bulk of mine workers tend to be production workers whose skills have developed over long periods of time. Production workers on mines have a tradition of long-term employment. This phenomenon has meant that labour in the mines is hard to replace as a result of skills, especially tacit knowledge, acquired over many years. Thus while the recent closure of some gold mines, largely due to low commodity prices, has meant that more miners are available in the labour market, this situation has not necessarily eased the process of replacing labour lost to the HIV/AIDS epidemic, as certain skills are firm specific. Production workers are predominantly male with the bulk falling in the 35,39 years age group. Most mine workers reside in mine villages, a colonial legacy that ensured miners were close to the workplace. The village system is a system of housing labourers, which demonstrates capitalistic methods of controlling labour and minimising costs. Of significance in this study's background is how the village system has come to be viewed as a factor in the spread of HIV/AIDS in the mining communities, because of its ,closed' nature. It is against this complex historical backdrop that the paper turns to examine the impact of the HIV/AIDS pandemic on production workers and management responses to the crisis using the Resource Based View of the Firm model (RBV), one of the theories in the Strategic Human Resource Management (SHRM) tradition. RBV was chosen for this study out of many HRM models that exist, because this theory, in particular, explains why it is advantageous for sites to use their ,unique' firm based resources in order to achieve sustainable competitive advantage. Given this rationale it was, therefore, presumed that this theory would best apply in mines battling with the adverse impact of HIV/AIDS on productivity, especially in the light of the harsh national economic climate, which would likely place limitations on response mechanisms. Further, the issue of firm-specific skills was also taken into consideration as an important factor in the mines, limiting their ability to resort to external solutions. Thus, given these factors, RBV was deemed the most appropriate model. The study finds that the pandemic depresses labour productivity through a number of significant ways: increased rate of HIV/AIDS induced absenteeism gradual labour turnover as a result of AIDS induced morbidity; and consequently declining skills availability, particularly firm-specific skills. Maintaining labour productivity in the face of gradually diminishing skills and indisposed labour will be key to softening the adverse economic consequences of the pandemic in the mines. To reduce the threat to labour productivity, mines must find ways of utilising, to the maximum extent practicable, existing skills. Results indicate that a move towards the utilisation of existing miners is the most favoured response mechanism in most mines. Utilising existing miners enables mines from spending financial resources on avoidable recruitment and training and quite often mechanisation, which may not necessarily be compatible with the old infrastructure in certain mines. Copyright © 2006 John Wiley & Sons, Ltd. [source] Microwave Dielectric Ceramics for Resonators and Filters in Mobile Phone NetworksJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2006Ian M. Reaney Temperature-stable, medium-permittivity dielectric ceramics have been used as resonators in filters for microwave (MW) communications for several decades. The growth of the mobile phone market in the 1990s led to extensive research and development in this area. The main driving forces were the greater utilization of available bandwidth, that necessitates extremely low dielectric loss (high-quality factor), an increase in permittivity so that smaller components could be fabricated, and, as ever in the commercial world, cost reduction. Over the last decade, a clear picture has emerged of the principal factors, that influence MW properties. This article reviews these basic principles and gives examples of where they have been used to control microwave properties and ultimately develop new materials. [source] Data fusion according to the principle of polyrepresentationJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 4 2009Birger Larsen We report data fusion experiments carried out on the four best-performing retrieval models from TREC 5. Three were conceptually/algorithmically very different from one another; one was algorithmically similar to one of the former. The objective of the test was to observe the performance of the 11 logical data fusion combinations compared to the performance of the four individual models and their intermediate fusions when following the principle of polyrepresentation. This principle is based on cognitive IR perspective (Ingwersen & Järvelin, 2005) and implies that each retrieval model is regarded as a representation of a unique interpretation of information retrieval (IR). It predicts that only fusions of very different, but equally good, IR models may outperform each constituent as well as their intermediate fusions. Two kinds of experiments were carried out. One tested restricted fusions, which entails that only the inner disjoint overlap documents between fused models are ranked. The second set of experiments was based on traditional data fusion methods. The experiments involved the 30 TREC 5 topics that contain more than 44 relevant documents. In all tests, the Borda and CombSUM scoring methods were used. Performance was measured by precision and recall, with document cutoff values (DCVs) at 100 and 15 documents, respectively. Results show that restricted fusions made of two, three, or four cognitively/algorithmically very different retrieval models perform significantly better than do the individual models at DCV100. At DCV15, however, the results of polyrepresentative fusion were less predictable. The traditional fusion method based on polyrepresentation principles demonstrates a clear picture of performance at both DCV levels and verifies the polyrepresentation predictions for data fusion in IR. Data fusion improves retrieval performance over their constituent IR models only if the models all are quite conceptually/algorithmically dissimilar and equally and well performing, in that order of importance. [source] An NMR study of cyclodextrin complexes of the steroidal neuromuscular blocker drug Rocuronium BromideMAGNETIC RESONANCE IN CHEMISTRY, Issue 4 2002Kenneth S. Cameron Abstract The interaction of Rocuronium Bromide, and a model steroid Org 7402, with three cyclodextrins (,-cyclodextrin, ,-cyclodextrin and Org 25969) was studied by solution state NMR experiments. Stoichiometries and binding constants were determined from 1H chemical shift titrations. All of the systems formed 1 : 1 complexes. Most of the complexes were in fast exchange with unbound species on the NMR time scale, but the most tightly bound complex (Rocuronium Bromide,Org 25969) was in the slow exchange regime. The geometry of the complexes was inferred from 1H and 13C NMR shift changes upon complexation and from intramolecular NOE correlations. Rocuronium Bromide forms a weak complex with ,-cyclodextrin (Ka = 3.3 ± 0.5 × 103M,1) and no clear picture of the structure of the complex emerges. The complexes with ,-cyclodextrin (Ka = 1.8 ± 0.2 × 104M,1) and Org 25969 (Ka > 105M,1) are true inclusion complexes with the steroid located inside the central void of the cyclodextrin. Copyright © 2002 John Wiley & Sons, Ltd. [source] Mitochondrial phylogeography of the Woodmouse (Apodemus sylvaticus) in the Western Palearctic regionMOLECULAR ECOLOGY, Issue 3 2003J. R. Michaux Abstract We sequenced 965 base pairs of the mitochondrial DNA cytochrome b from 102 woodmice (Apodemus sylvaticus) collected from 40 European localities. The aims of the study were to answer the following questions. (i) Did the Mediterranean peninsulas play a role as refuge for woodmice? (ii) Is genetic variability of A. sylvaticus higher in the Mediterranean region compared with northern Europe? (iii) Are the patterns of the postglacial colonization of Europe by woodmice similar to those presently recognized for other European species? The results provide a clear picture of the impact of the Quaternary glaciations on the genetic and geographical structure of the woodmouse. Our analyses indicate a higher genetic variability of woodmice in the Mediterranean peninsulas compared to northern Europe, suggesting a role of the former as refuge regions for this small mammal. An original pattern of postglacial colonization is proposed where the Iberian and southern France refuge populations colonized almost all European regions. The Sicilian population appears to be very differentiated and highly variable. This emphasizes the importance of this island as a ,hot spot' for the intraspecific genetic diversity of the woodmouse. Finally, woodmice in North Africa originated from southwestern Europe, most probably as a result of a recent anthropogenic introduction. [source] Effects of altered water regimes on forest root systemsNEW PHYTOLOGIST, Issue 1 2000J. D. JOSLIN How ecosystems adapt to climate changes depends in part on how individual trees allocate resources to their components. A review of research using tree seedlings provides some support for the hypothesis that some tree species respond to exposure to drought with increases in root,shoot ratios but little change in total root biomass. Limited research on mature trees over moderately long time periods (2,10 yr), has given mixed results with some studies also providing evidence for increases in root: shoot ratios. The Throughfall Displacement Experiment (TDE) was designed to simulate both an increase and a decrease of 33% in water inputs to a mature deciduous forest over a number of years. Belowground research on TDE was designed to examine four hypothesized responses to long-term decreases in water availability; (1) increases in fine-root biomass, (2) increases in fine root,foliage ratio, (3) altered rates of fine-root turnover (FRT), and (4) depth of rooting. Minirhizotron root elongation data from 1994 to 1998 were examined to evaluate the first three hypotheses. Differences across treatments in net fine-root production (using minirhizotron root elongation observations as indices of biomass production) were small and not significant. Periods of lower root production in the dry treatment were compensated for by higher growth during favorable periods. Although not statistically significant, both the highest production (20 to 60% higher) and mortality (18 to 34% higher) rates were found in the wet treatment, resulting in the highest index of FRT. After 5 yr, a clear picture of stand fine-root-system response to drought exposure has yet to emerge in this forest ecosystem. Our results provide little support for either an increase in net fine-root production or a shift towards an increasing root,shoot ratio with long-term drought exposure. One possible explanation for higher FRT rates in the wet treatment could be a positive relationship between FRT and nitrogen and other nutrient availability, as treatments have apparently resulted in increased immobilization of nutrients in the forest floor litter under drier conditions. Such hypotheses point to the continued need to study the interactions of water stress, nutrient availability and carbon-fixation efficiency in future long-term studies. [source] Signal Transfer in Haloarchaeal Sensory Rhodopsin, Transducer Complexes,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2008Jun Sasaki Membrane-inserted complexes consisting of two photochemically reactive sensory rhodopsin (SR) subunits flanking a homodimer of a transducing protein subunit (Htr) are used by halophilic archaea for sensing light gradients to modulate their swimming behavior (phototaxis). The SR,Htr complexes extend into the cytoplasm where the Htr subunits bind a his-kinase that controls a phosphorylation system that regulates the flagellar motors. This review focuses on current progress primarily on the mechanism of signal relay within the SRII,HtrII complexes from Natronomonas pharaonis and Halobacterium salinarum. The recent elucidation of a photoactive site steric trigger crucial for signal relay, advances in understanding the role of proton transfer from the chromophore to the protein in SRII activation, and the localization of signal relay to the membrane-embedded portion of the SRII,HtrII interface, are beginning to produce a clear picture of the signal transfer process. The SR,Htr complexes offer unprecedented opportunities to resolve first examples of the chemistry of signal relay between membrane proteins at the atomic level, which would provide a major contribution to the general understanding of dynamic interactions between integral membrane proteins. [source] New magnetic field measurements of , Cephei stars and slowly pulsating B stars,ASTRONOMISCHE NACHRICHTEN, Issue 4 2009S. Hubrig Abstract We present the results of the continuation of our magnetic survey with FORS 1 at the VLT of a sample of B-type stars consisting of confirmed or candidate , Cephei stars and Slowly Pulsating B (hereafter SPB) stars, along with a small number of normal B-type stars. A weak mean longitudinal magnetic field of the order of a few hundred Gauss was detected in three , Cephei stars and two stars suspected to be , Cephei stars, in five SPB stars and eight stars suspected to be SPB stars. Additionally, a longitudinal magnetic field at a level larger than 3, has been diagnosed in two normal B-type stars, the nitrogen-rich early B-type star HD 52089 and in the B5 IV star HD 153716. Roughly one third of , Cephei stars have detected magnetic fields: Out of 13 , Cephei stars studied to date with FORS 1, four stars possess weak magnetic fields, and out of the sample of six suspected , Cephei stars two show a weak magnetic field. The fraction of magnetic SPBs and candidate SPBs is found to be higher: Roughly half of the 34 SPB stars have been found to be magnetic and among the 16 candidate SPBs eight stars possess magnetic fields. In an attempt to understand why only a fraction of pulsating stars exhibit magnetic fields, we studied the position of magnetic and non-magnetic pulsating stars in the H-R diagram. We find that their domains in the H-R diagram largely overlap, and no clear picture emerges as to the possible evolution of the magnetic field across the main sequence. It is possible that stronger fields tend to be found in stars with lower pulsating frequencies and smaller pulsating amplitudes. A somewhat similar trend is found if we consider a correlation between the field strength and the v sin i -values, i.e. stronger magnetic fields tend to be found in more slowly rotating stars (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Re-Formulating Non-inferiority Trials as Superiority Trials: The Case of Binary OutcomesBIOMETRICAL JOURNAL, Issue 1 2009Valerie L. Durkalski Abstract Non-inferiority trials are conducted for a variety of reasons including to show that a new treatment has a negligible reduction in efficacy or safety when compared to the current standard treatment, or a more complex setting of showing that a new treatment has a negligible reduction in efficacy when compared to the current standard yet is superior in terms of other treatment characteristics. The latter reason for conducting a non-inferiority trial presents the challenge of deciding on a balance between a suitable reduction in efficacy, known as the non-inferiority margin, in return for a gain in other important treatment characteristics/findings. It would be ideal to alleviate the dilemma on the choice of margin in this setting by reverting to a traditional superiority trial design where a single p -value for superiority of both the most important endpoint (efficacy) and the most important finding (treatment characteristic) is provided. We discuss how this can be done using the information-preserving composite endpoint (IPCE) approach and consider binary outcome cases in which the combination of efficacy and treatment characteristics, but not one itself, paints a clear picture that the novel treatment is superior to the active control (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Comprehensive Study on the Solids Acceleration Length in a Long CFB RiserCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 10 2006W-X. Huang Abstract Systematic experimental work was conducted to investigate the solids acceleration length in a 0.10,m i. d., 16,m long circulating fluidized bed (CFB) riser with fluid catalytic cracking (FCC) particles over a wide range of operating conditions. A more feasible method is proposed to determine the acceleration length from the measured axial profiles of pressure gradient (or apparent solids holdup). With this new method and large amounts of experimental results, a clear picture of the variation of the acceleration length with both solids circulating rate and superficial gas velocity is obtained. It is found that the acceleration length increases generally with increasing solids flow rate and/or decreasing gas velocity. However, the particular variation patterns of the acceleration length with operating conditions are quite different in different operation ranges. Especially under the conditions near or at the accumulative choking, the acceleration length extends rapidly with increasing solids flow rate and/or decreasing gas velocity, and sometimes takes up the whole riser height. Reasonable explanations are provided for the observed variation patterns of the acceleration length. [source] Solid,Solid Phase Transitions: Interface Controlled Reactivity and Formation of Intermediate StructuresCHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2007Stefano Leoni Dr. Abstract Finding new pathways to novel materials is an open challenge in modern solid-state chemistry. Among the reasons that still prevent a rational planning of synthetic routes is the lack of an atomistic understanding at the moment of phase formation. Metastable phases are, in this respect, powerful points of access to new materials. For the synthetic efforts to fully take advantage of such peculiar intermediates, a precise atomistic understanding of critical processes in the solid state in its many facets, that is, nucleation patterns, formation and propagation of interfaces, intermediate structures, and phase growth, is mandatory. Recently we have started a systematic theoretical study of phase transitions, especially of processes with first-order thermodynamics, to reach a firm understanding of the atomistic mechanisms governing polymorphism in the solid state. A clear picture is emerging of the interplay between nucleation patterns, the evolution of domain interfaces and final material morphology. Therein intermediate metastable structural motifs with distinct atomic patterns are identified, which become exciting targets for chemical synthesis. Accordingly, a new way of implementing simulation strategies as a powerful support to the chemical intuition is emerging. Simulations of real materials under conditions corresponding to the experiments are shedding light onto yet elusive aspects of solid,solid transformations. Particularly, sharp insights into local nucleation and growth events allow the formulation of new concepts for rationalizing interfaces formed during phase nucleation and growth. Structurally different and confined in space, metastable interfaces occurring during polymorph transformations bring about distinct diffusion behavior of the chemical species involved. More generally, stable structures emerge as a result of the concurrence of the transformation mechanism and of chemical reactions within the phase-growth fronts. [source] Structural Analysis of Chiral Complexes of Palladium(0) with 15-Membered Triolefinic Macrocyclic LigandsCHEMISTRY - A EUROPEAN JOURNAL, Issue 9 2005Anna Pla-Quintana Abstract The complete structural analysis of the palladium complexes of the triolefinic macrocycles (E,E,E)-1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-trienes, which featured from three identical to three different aryl groups, was achieved by performing X-ray diffraction studies, NMR spectroscopy, and other calculations. The stereochemical complexity is determined by the different isomers formed through complexation of the metal to one or other face of each of the three olefins involved. The palladacyclopropane formulation of the palladium,olefin interaction offers a clear picture of the stereogenicity of the olefin carbon atoms that are complexed to the metal. The energetically favorable isomers were identified in the solid-state and in solution by performing X-ray diffraction and NMR spectroscopic analysis, respectively. Els complexos de pal,ladi de macrocicles triolefínics de tipus (E,E,E)-1,6,11-tris(arilsulfonil)-1,6,11-triazaciclopentadeca-3,8,13-triè, contenint des de tres unitats aríliques iguals fins a tres de diferents han estat estudiats mitjançant difracció de Raigs-X, espectroscòpia de RMN i càlculs teòrics. La complexitat estereoquímica deriva dels diferents isomers que es poden formar degut a la complexació del metall amb cadascuna de les dues cares de les tres olefines. La representació dels enllaços metall-olefina com a pal,ladaciclopropans permet una visualització més senzilla de l,estereoquímica dels àtoms de carboni olefínics després de la complexació. Els isomers energèticament possibles han estat determinats en l,estat sòlid i en solució mitjançant difracció de Raigs-X i espectroscòpia de RMN respectivament. [source] Fatty acid composition abnormalities in atopic disease: evidence explored and role in the disease process examinedCLINICAL & EXPERIMENTAL ALLERGY, Issue 9 2008A. Sala-Vila Summary There is a hypothesis causally linking excess intake of n-6 polyunsaturated fatty acids (PUFAs) to atopic disease. Under most dietary conditions, the main precursor of eicosanoids is the n-6 PUFA arachidonic acid (AA). AA-derived eicosanoids play many roles in sensitization to allergens and in allergic inflammation. Long chain n-3 PUFAs inhibit AA incorporation into cell membranes and inhibit AA metabolism to eicosanoids. It is hypothesized that atopy is associated with a higher n-6 PUFA status and with a low n-3 PUFA status. However, measurements of fatty acid composition do not provide a clear picture that such fatty acid abnormalities exist in atopy with no really clear pattern of altered status of a particular fatty acid or a particular fatty acid family. There are few reports of elevated linoleic acid in atopy. Some studies report lower amounts of the n-6 PUFAs, including AA, and of long chain n-3 PUFAs in atopy, although observations on this are not consistent. Taken together these data clearly do not support the hypothesis that atopy is somehow associated with a high exposure to, and status of, n-6 PUFAs. Intervention studies with n-3 PUFAs in pregnant women, infants and children suggest some clinical benefits, although how long lasting these are remains to be determined. The observation that there may be low AA status in atopy suggests that fish oil intervention, which targets AA status and metabolism, may not be ideal and that a combination of fish oil with some longer chain n-6 PUFAs may be more efficacious. [source] Surveillance of antibiotic use in hospitals: methods, trends and targetsCLINICAL MICROBIOLOGY AND INFECTION, Issue 8 2006E. I. Kritsotakis Abstract A standardised antibiotic surveillance system is an essential requirement of all antibiotic control strategies. Antibiotic use can be quantified accurately using patient-level surveillance, although this is not feasible for most hospitals. Instead, population-level surveillance is a more realistic alternative for ongoing and systematic monitoring of antibiotic use. Monitoring of aggregate, ward-supply data on a monthly basis, stratification by patient care area, and analysis by the anatomical therapeutic chemical/defined daily dose (ATC/DDD) system, adjusting for bed-occupancy, provides a clear picture of antibiotic consumption density and time-trends within a hospital. When usage rates are supplemented and interpreted according to changes in hospital resource indicators, benchmarking is facilitated. This provides an efficient tool for triggering and targeting antibiotic control interventions. [source] Parental rearing styles and personality disorders in prisoners and forensic patientsCLINICAL PSYCHOLOGY AND PSYCHOTHERAPY (AN INTERNATIONAL JOURNAL OF THEORY & PRACTICE), Issue 3 2005Irma G. H. Timmerman In the present study it was hypothesized that men with a criminal status (forensic inpatients and prisoners) would report more pathological rearing styles of their parents than men from the general population, after accounting for the influence of personality pathology. The results showed that forensic inpatients reported significantly less care from their mothers and more protection from both parents. No differences on paternal care were found though. The prisoners were less clearly distinguished from normal controls with respect to parental rearing. They perceived their fathers as more protective, however, only when the influence of the personality disorder category was controlled for and not when the influence of personality disorder features was controlled for. Further, prisoners perceived their mothers as significantly more caring. The results with respect to criminal and patient status stayed the same after controlling for the influence of personality pathology. The analyses further showed that cluster B pathology when measured as one construct was significantly associated with all parental rearing variables: less care and more protection. Also, cluster A and cluster C pathology, criminal status and inpatients status did not influence these results. When the cluster B disorders were examined separately though, a less clear picture emerged. The categorical defined borderline personality disorder was significantly related to all four rearing variables: less care and more protection. For cluster C pathology the opposite was found: when measured categorically no significant relations with rearing were found and when measured dimensionally all relations were significant. When measured dimensionally, antisocial personality features were significantly associated with less care from both parents and with more protection from the mother. When measured categorically, only the relationship with care of father remained significant. Finally, cluster A pathology was related significantly only to (low) maternal care.,Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||