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Declining
Terms modified by Declining Selected AbstractsPopulation Size, Genetic Variation, and Reproductive Success in a Rapidly Declining, Self-Incompatible Perennial (Arnica montana) in The NetherlandsCONSERVATION BIOLOGY, Issue 6 2000Sheila H. Luijten In 26 populations in The Netherlands we investigated the relationship between population size and genetic variation using allozyme markers. Genetic variation was low in A. montana ( He = 0.088). There were positive correlations between population size and the proportion of polymorphic loci, the number of effective alleles, and expected heterozygosity, but not with observed heterozygosity. There was a significantly positive correlation between population size and the inbreeding coefficient. Generally, small populations showed heterozygote excess, which decreased with increasing population size. Possibly, the heterozygous individuals in small populations are survivors from the formerly larger populations with relatively high fitness. The F statistics showed a moderately high level of differentiation among populations ( FST = 0.140 ± 0.02), implying a low level of gene flow. For three out of four allozyme loci, we found significant inbreeding ( FIS = 0.104 ± 0.03). Only 14 of 26 populations were in Hardy-Weinberg equilibrium at all four polymorphic loci. In a subset of 14 populations of various size, we investigated natural seed production and offspring fitness. Population size was positively correlated with seed set, seedling size, number of flowering stems and flowerheads, adult survival, and total relative fitness, but not with the number of florets per flowerhead, germination rate, or the proportion of germination. Offspring performance in the greenhouse was not associated with genetic diversity measured on their mothers in the field. We conclude that the fitness of small populations is significantly reduced, but that there is as yet no evidence that this was caused by inbreeding. Possibly, the self-incompatibility system of A. montana has been effective in reducing selfing rates and inbreeding depression. Resumen:Arnica montana es una especie de planta rara, en declinación rápida y autoincompatible. En 26 poblaciones de los Países Bajos investigamos la relación entre el tamaño poblacional y la variación genética mediante el uso de alozimas marcadoras. La variación genética fue baja en A. montana ( He = 0.088). Existió una correlación positiva entre el tamaño poblacional y la proporción de emplazamientos polimórficos, el número de alelos efectivos y la heterocigocidad esperada, pero no con la heterocigocidad observada. Existió una correlación positiva significativa entre el tamaño poblacional y el coeficiente de endogamia. Generalmente, las poblaciones pequeñas mostraron una heterocigocidad excesiva con disminuciones en el tamaño poblacional. Posiblemente, los individuos heterocigóticos de poblaciones pequeñas son sobrevivientes de poblaciones anteriormente grandes con una adaptabilidad relativamente alta. Las pruebas de F mostraron un nivel de diferenciación moderadamente alto entre poblaciones ( FST = 0.140 ± 0.02) lo que implica un nivel bajo de flujo de genes. Para tres de cuatro de los emplazamientos de alozimas encontramos una endogamia significativa ( FIS = 0.104 ± 0.03). Solamente 14 de las 26 poblaciones estuvieron en equilibrio Hardy-Weinberg para los cuatro emplazamientos polimórficos. En un subconjunto de 14 poblaciones de varios tamaños, investigamos la producción natural de semillas y la adaptabilidad de la descendencia. El tamaño poblacional estuvo positivamente correlacionado con el juego de semillas, el tamaño del almácigo, el número de tallos en flor y de inflorescencias, la supervivencia de adultos y la adaptabilidad total relativa, pero no con el número de flores por inflorescencia, la tasa de germinación ni la proporción de la germinación. El rendimiento de la descendencia en invernaderos no estuvo asociado con la diversidad genética medida en sus madres en el campo. Concluimos que la adaptabilidad de poblaciones pequeñas está significativamente reducida, pero no existe aún evidencia de que esto sea ocasionado por endogamia. Es posible que el sistema de autoincompatibilidad de A. montana haya sido efectivo en la reducción de tasas de autofecundación y depresión de la endogamia. [source] Youth Smoking Declining; Much Work RemainsNURSING FOR WOMENS HEALTH, Issue 3 2002Carolyn Davis Cockey No abstract is available for this article. [source] Why Is Late-Life Disability Declining?THE MILBANK QUARTERLY, Issue 1 2008ROBERT F. SCHOENI Context: Late-life disability has been declining in the United States since the 1980s. This study provides the first comprehensive investigation into the reasons for this trend. Methods: The study draws on evidence from two sources: original data analyses and reviews of existing studies. The original analyses include trend models of data on the need for help with daily activities and self-reported causes of such limitations for the population aged seventy and older, based on the National Health Interview Surveys from 1982 to 2005. Findings: Increases in the use of assistive and mainstream technologies likely have been important, as have declines in heart and circulatory conditions, vision, and musculoskeletal conditions as reported causes of disability. The timing of the improvements in these conditions corresponds to the expansion in medical procedures and pharmacologic treatment for cardiovascular disease, increases in cataract surgery, increases in knee and joint replacements, and expansion of medications for arthritic and rheumatic conditions. Greater educational attainment, declines in poverty, and declines in widowhood also appear to have contributed. Changes in smoking behavior, the population's racial/ethnic composition, the proportion of foreign born, and several specific conditions were eliminated as probable causes. Conclusions: The substantial reductions in old-age disability between the early 1980s and early 2000s are likely due to advances in medical care as well as changes in socioeconomic factors. More research is needed on the influence of health behaviors, the environment, and early- and midlife factors on trends in late-life disability. [source] Declining and low fecal corticoids are associated with distress, not acclimation to stress, during the translocation of African rhinocerosANIMAL CONSERVATION, Issue 1 2010W. L. Linklater Abstract Concentrations of adrenal steroid metabolites in feces are routinely used to assess the welfare of animals that are the subject of conservation efforts. The assumption that low and declining corticoid concentrations indicate the absence of stress and acclimation, respectively, is often made without experimental support or wild-animal comparisons, although intrinsic control of adrenal steroids might occur even under ongoing stress and distress. We adopted the capture and 11-week captivity of 18 black (Diceros bicornis: 11 males, seven females) and 52 white (Ceratotherium simum: 22 males, 30 females) rhinoceros as an experimental test of the relationship between corticoid concentrations and stress (translocation) and measured for suppressed gonad function as an indicator of distress , the biological cost of cumulative stressors. Fecal samples collected from the rectum at capture and during captivity were stored frozen and their corticoid, and androgen (in males) or progestin (in females), concentrations determined by radioimmunoassay. Corticoid profiles followed the expected pattern of being two to five times pre-capture levels (ng g,1: black rhino: female 24.5±3.7, male 23.9±2.2; white rhino: female 16.3±1.6, male 12.3±2.4) for up to 17 days after capture and declined with time in captivity. Black rhinoceros and male white rhinoceros corticoids declined below pre-capture values and were associated with suppressed levels of androgens and progestins with increased time in captivity. Declining corticoids could not be interpreted as acclimation or the absence of stressors, without also measuring for distress in African rhinoceros. White rhinoceros female corticoid values remained elevated, although their gonad steroid levels were also suppressed. We discuss our findings for the management of rhinoceros in the wild and captivity. [source] Patch Occupancy and Potential Metapopulation Dynamics of Three Forest Mammals in Fragmented Afromontane Forest in South AfricaCONSERVATION BIOLOGY, Issue 4 2000Michael J. Lawes We recorded patch occupancy of blue duiker ( Philantomba monticola), tree hyrax ( Dendrohyrax arboreus), and samango monkey (Cercopithecus mitis labiatus) in 199 forest patches. Their rarity is ascribed to the fragmentation and destruction of their forest habitat. Incidence functions, derived from presence and absence data, were formulated as generalized linear models, and environmental effects were included in the fitted logistic models. The small and mostly solitary hyrax and duiker persisted in smaller patches than the large and social monkey. Although this result follows expectations based on relative home-range sizes of each species, the incidence probability of the samango monkey was invariant with increasing isolation, whereas a gradual decrease with increasing isolation was observed for the hyrax and duiker. Group dynamics may inhibit dispersal and increase the isolation effect in social species such as samango monkeys. A mainland-island metapopulation model adequately describes patterns of patch occupancy by the hyrax and duiker, but the monkeys' poor dispersal ability and obvious area-dependent extirpation suggest that they exist in transient, nonequilibrium (declining) metapopulations. Through identification of large forest patches for careful protection and management, the survival of all three species,especially the monkey,could be prolonged. Because no functional metapopulation may exist for the monkey, however, this is an emergency measure. For the duiker and hyrax, larger patches should form part of a network of smaller and closer patches in a natural matrix. Resumen: Investigamos la persistencia de tres mamíferos forestales raros de tamaño mediano (2,9 kg) en los bosques fragmentados de cinturón de niebla Podocarpus en la región central de la provincia KwaZulu-Natal, Sudáfrica. Registramos la ocupación del duiker azul ( Philantomba monticola), el hyrax arborícola ( Dendrohyrax arboreus) y el mono samango (Cercopithecus mitis labiatus) en 199 parches forestales. Su rareza se atribuye a la fragmentación y destrucción de su hábitat forestal. Las funciones de incidencia, derivadas de datos de presencia y ausencia, fueron formuladas como modelos lineales generalizados, y los efectos ambientales fueron incluidos en los modelos logísticos ajustados. Los pequeños y mayormente solitarios hyrax y duiker persistieron en parches más pequeños que los monos, que son más grandes y más sociables. A pesar de que este resultado obedece a expectativas basadas en tamaños de rango de hogar relativos de cada especie, la probabilidad de incidencia del mono samango no cambió con un incremento en el aislamiento, mientras que una disminución gradual al crecer el aislamiento se observó en hyrax y duiker. Las dinámicas de grupos podrían inhibir la dispersión e incrementar el efecto de aislamiento en especies sociables como lo es el mono samango. Un modelo de metapoblación continente-isla describe adecuadamente los patrones de la ocupación de parches por hyrax y duiker; sin embargo, la pobre capacidad de dispersión de los monos y la obvia extirpación área-dependente sugiere que estos existen en metapoblaciones transitorias, desequilibradas (en disminución). Mediante la identificación de parches forestales grandes para la protección y manejo cuidadosos, la supervivencia de las tres especies ( pero especialmente la de los monos) podría ser prolongada. Sin embargo, debido a que no existen metapoblaciones funcionales de monos, esta es una medida de emergencia. Para el duiker y el hyrax, los parches grandes deberán formar parte de una red de parches más pequeños y más cercanos en una matriz natural. [source] Risk factors and outcome in ambulatory assault victims presenting to the acute emergency department setting: Implications for secondary prevention studies in PTSDDEPRESSION AND ANXIETY, Issue 2 2004Peter P. Roy-Byrne M.D. Abstract Prevention of post-traumatic stress disorder (PTSD) in trauma victims is an important public health goal. Planning for the studies required to validate prevention strategies requires identification of subjects at high risk and recruitment of unbiased samples that represent the larger high-risk population (difficult because of the avoidance of many trauma victims). This study recruited high-risk victims of interpersonal violence (sexual or physical assault) presenting to an urban emergency department for prospective 1- and 3-month follow-up. Of 546 victims who were approached about participating, only 56 agreed to be contacted and only 46 participated in either the 1- or 3-month interviews. Of the 46, 43 had been previously victimized with a mean of over six traumas in the group; 21% had prior PTSD, 85% had prior psychiatric illness, and 37% had prior substance abuse. Sixty-seven percent had positive urine for alcohol or drugs on presentation. Fifty-six percent developed PTSD at 1 or 3 months with the rate declining between 1 and 3 months. There was high use of medical and psychiatric services. These findings document both the difficulty of recruiting large samples of high-risk assault victims to participate in research, and the high rate of prior traumatization, PTSD, substance use, and psychiatric morbidity in these subjects which, if still active at the time of victimization, may complicate efforts to document preventive treatment effects. Depression and Anxiety 19:77,84, 2004. © 2004 Wiley-Liss, Inc. [source] More power to the European Parliament?ECONOMIC POLICY, Issue 35 2002Abdul G. Noury SUMMARY Many observers have expressed scepticism about granting more power to the European Parliament. The sceptics believe that Members of the European Parliament (MEPs) do not vote in a disciplined way and that they vote more often with their country group than with their European Party. Using a unique database consisting of all roll call votes by each individual MEP between 1989 and 1999 (over 6000 votes by over 1000 different MEPs), we show that the sceptics are wrong. Our data shows clearly that MEPs vote more along party lines than along country lines. Party cohesion is comparable to that of the US Congress and is increasing over time whereas country cohesion is low and declining. In short, politics in the European Parliament generally follows the traditional left,right divide that one finds in all European nations. These findings are valid across issues, even on issues like the structural and cohesion funds where one would expect country rather than party cohesion. In votes where the EP has the most power , those held under the so-called co-decision procedure , MEPs participate more and are more party-cohesive. In our opinion, this unique empirical analysis provides grounds for justifying a generalization of the co-decision procedure. [source] Coordinated Development of Yeast Colonies: An Experimental Analysis of the Adaptation to Different Nutrient Concentrations , Part 1ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 2 2005T. Walther Abstract The development of yeast colonies on solid agar substrates served as a model system to investigate the growth of higher fungi in a heterogeneous environment. Applying a new analytical technique , which was based on the estimation of the intensity of transmitted light from microscopic images taken along the colony radius , cell-density distributions inside fungal mycelia were measured at an extremely high spatial resolution. Using this method, the adaptation of yeast colonies to the limitation of different nutrients was investigated. Under conditions of carbon or nitrogen limitation, populations of the dimorphic model yeasts Yarrowia lipolytica and Candida boidinii underwent a transition in their morphology from solid colony to mycelial colony patterns. When grown under conditions that induced the mycelial morphology, colonies extended linearly at a constant rate irrespective of the initial nutrient concentration. In general, the cell density within the population declined at higher degrees of limitation. Nitrogen-limited colonies of both model yeasts, as well as carbon-limited Y.,lipolytica colonies proceeded to extend until the growth field was finally covered by the population. Under these conditions, areas of fairly constant cell densities were formed during the growth process. Only carbon-limited C.,boidinii colonies stopped extending at a final diameter which was small when compared to the size of the growth field, and formed a cell-density profile which was monotonically declining. The observed differences in the final colony diameter, and in the cell-density profile morphology indicated the presence of different regulatory mechanisms that ruled the colony development of the model yeasts. The presented monitoring technique for the biomass distribution inside fungal populations provided the basis for a quantitative and non-invasive description of mycelial development. [source] A high frequency kriging approach for non-stationary environmental processesENVIRONMETRICS, Issue 5 2001Montserrat Fuentes Abstract Emission reductions were mandated in the Clean Air Act Amendments of 1990 with the expectation that they would result in major reductions in the concentrations of atmospherically transported pollutants. The emission reductions are intended to reduce public health risks and to protect sensitive ecosystems. To determine whether the emission reductions are having the intended effect on atmospheric concentrations, monitoring data must be analyzed taking into consideration the spatial structure shown by the data. Maps of pollutant concentrations and fluxes are useful over different geopolitical boundaries, to discover when, where, and to what extent the U.S. Nation's air quality is improving or declining. Since the spatial covariance structure shown by the data changes with location, the standard kriging methodology for spatial interpolation cannot be used because it assumes stationarity of the process. We present a new methodology for spatial interpolation of non-stationary processes. In this method the field is represented locally as a stationary isotropic random field, but the parameters of the stationary random field are allowed to vary across space. A procedure for interpolation is presented that uses an expression for the spectral density at high frequencies. New fitting algorithms are developed using spectral approaches. In cases where the data are distributed exactly or approximately on a lattice, it is argued that spectral approaches have potentially enormous computational benefits compared with maximum likelihood. The methods are extended to interpolation questions using approximate Bayesian approaches to account for parameter uncertainty. We develop applications to obtain the total loading of pollutant concentrations and fluxes over different geo-political boundaries. Copyright © 2001 John Wiley & Sons, Ltd. [source] Is Parkinson's disease-related mortality declining?EUROPEAN JOURNAL OF NEUROLOGY, Issue 9 2009E. Haberfeld No abstract is available for this article. [source] Worldwide status of burbot and conservation measuresFISH AND FISHERIES, Issue 1 2010Martin A Stapanian Abstract Although burbot (Lota lota Gadidae) are widespread and abundant throughout much of their natural range, there are many populations that have been extirpated, endangered or are in serious decline. Due in part to the species' lack of popularity as a game and commercial fish, few regions consider burbot in management plans. We review the worldwide population status of burbot and synthesize reasons why some burbot populations are endangered or declining, some burbot populations have recovered and some burbot populations do not recover despite management measures. Burbot have been extirpated in much of Western Europe and the United Kingdom and are threatened or endangered in much of North America and Eurasia. Pollution and habitat change, particularly the effects of dams, appear to be the main causes for declines in riverine burbot populations. Pollution and the adverse effects of invasive species appear to be the main reasons for declines in lacustrine populations. Warmer water temperatures, due either to discharge from dams or climate change, have been noted in declining burbot populations at the southern extent of their range. Currently, fishing pressure does not appear to be limiting burbot populations world-wide. We suggest mitigation measures for burbot population recovery, particularly those impacted by dams and invasive species. [source] An individual-based model of the early life history of mackerel (Scomber scombrus) in the eastern North Atlantic, simulating transport, growth and mortalityFISHERIES OCEANOGRAPHY, Issue 6 2004J. Bartsch Abstract The main purpose of this paper is to provide the core description of the modelling exercise within the Shelf Edge Advection Mortality And Recruitment (SEAMAR) programme. An individual-based model (IBM) was developed for the prediction of year-to-year survival of the early life-history stages of mackerel (Scomber scombrus) in the eastern North Atlantic. The IBM is one of two components of the model system. The first component is a circulation model to provide physical input data for the IBM. The circulation model is a geographical variant of the HAMburg Shelf Ocean Model (HAMSOM). The second component is the IBM, which is an i-space configuration model in which large numbers of individuals are followed as discrete entities to simulate the transport, growth and mortality of mackerel eggs, larvae and post-larvae. Larval and post-larval growth is modelled as a function of length, temperature and food distribution; mortality is modelled as a function of length and absolute growth rate. Each particle is considered as a super-individual representing 106 eggs at the outset of the simulation, and then declining according to the mortality function. Simulations were carried out for the years 1998,2000. Results showed concentrations of particles at Porcupine Bank and the adjacent Irish shelf, along the Celtic Sea shelf-edge, and in the southern Bay of Biscay. High survival was observed only at Porcupine and the adjacent shelf areas, and, more patchily, around the coastal margin of Biscay. The low survival along the shelf-edge of the Celtic Sea was due to the consistently low estimates of food availability in that area. [source] Trends in water quality and discharge confound long-term warming effects on river macroinvertebratesFRESHWATER BIOLOGY, Issue 2 2009ISABELLE DURANCE Summary 1.,Climate-change effects on rivers and streams might interact with other pressures, such as pollution, but long-term investigations are scarce. We assessed trends among macroinvertebrates in 50 southern English streams in relation to temperature, discharge and water quality over 18 years (1989,2007). 2.,Long-term records, coupled with estimates from inter-site calibrations of 3,4 years, showed that mean stream temperatures in the study area had increased by 2.1,2.9 °C in winter and 1.1,1.5 °C in summer over the 26 year period from 1980 to 2006, with trends in winter strongest. 3.,While invertebrate assemblages in surface-fed streams were constant, those in chalk-streams changed significantly during 1989,2007. Invertebrate trends correlated significantly with temperature, but effects were spurious because (i) assemblages gained taxa typical of faster flow or well-oxygenated conditions, contrary to expectations from warming; (ii) more invertebrate families increased in abundance than declined and (iii) concomitant changes in water quality (e.g. declining orthophosphate, ammonia and biochemical oxygen demand), or at some sites changes in discharge, explained more variation in invertebrate abundance and composition than did temperature. 4.,These patterns were reconfirmed in both group- and site-specific analyses. 5.,We conclude that recent winter-biased warming in southern English chalk-streams has been insufficient to affect invertebrates negatively over a period of improving water quality. This implies that positive management can minimize some climate-change impacts on stream ecosystems. Chalk-stream invertebrates are sensitive, nevertheless, to variations in discharge, and detectable changes could occur if climate change alters flow pattern. 6.,Because climatic trends now characterize many inter-annual time-series, we caution other investigators to examine whether putative effects on ecological systems are real or linked spuriously to other causes of change. [source] Occupational Segregation and the Tipping Phenomenon: The Contrary Case of Court Reporting in the USAGENDER, WORK & ORGANISATION, Issue 2 2007Joyce P. Jacobsen The ,tipping' phenomenon, whereby an occupation switches from dominance by one demographic group to dominance by another, has occurred in various occupations. Multiple causes have been suggested for such switches, including several related to technological change, both through effects on the performance of the work and through the effect of changing demand for different occupations. The court reporting occupation provides a novel setting for testing the relevance of various proposed causes for the increased feminization of many occupations. In this case, many of the general correlates, including declining wages, are not found; rather the phenomenon is related to the earlier feminization of the clerical workforce and the increased identification of court reporting with clerical work. [source] The regional variation of aboveground live biomass in old-growth Amazonian forestsGLOBAL CHANGE BIOLOGY, Issue 7 2006YADVINDER MALHI Abstract The biomass of tropical forests plays an important role in the global carbon cycle, both as a dynamic reservoir of carbon, and as a source of carbon dioxide to the atmosphere in areas undergoing deforestation. However, the absolute magnitude and environmental determinants of tropical forest biomass are still poorly understood. Here, we present a new synthesis and interpolation of the basal area and aboveground live biomass of old-growth lowland tropical forests across South America, based on data from 227 forest plots, many previously unpublished. Forest biomass was analyzed in terms of two uncorrelated factors: basal area and mean wood density. Basal area is strongly affected by local landscape factors, but is relatively invariant at regional scale in moist tropical forests, and declines significantly at the dry periphery of the forest zone. Mean wood density is inversely correlated with forest dynamics, being lower in the dynamic forests of western Amazonia and high in the slow-growing forests of eastern Amazonia. The combination of these two factors results in biomass being highest in the moderately seasonal, slow growing forests of central Amazonia and the Guyanas (up to 350 Mg dry weight ha,1) and declining to 200,250 Mg dry weight ha,1 at the western, southern and eastern margins. Overall, we estimate the total aboveground live biomass of intact Amazonian rainforests (area 5.76 × 106 km2 in 2000) to be 93±23 Pg C, taking into account lianas and small trees. Including dead biomass and belowground biomass would increase this value by approximately 10% and 21%, respectively, but the spatial variation of these additional terms still needs to be quantified. [source] The recent declines of farmland bird populations in Britain: an appraisal of causal factors and conservation actionsIBIS, Issue 4 2004Ian Newton In this paper, the main aspects of agricultural intensification that have led to population declines in farmland birds over the past 50 years are reviewed, together with the current state of knowledge, and the effects of recent conservation actions. For each of 30 declining species, attention is focused on: (1) the external causes of population declines, (2) the demographic mechanisms and (3) experimental tests of proposed external causal factors, together with the outcome of (4) specific conservation measures and (5) agri-environment schemes. Although each species has responded individually to particular aspects of agricultural change, certain groups of species share common causal factors. For example, declines in the population levels of seed-eating birds have been driven primarily by herbicide use and the switch from spring-sown to autumn-sown cereals, both of which have massively reduced the food supplies of these birds. Their population declines have been associated with reduced survival rates and, in some species, also with reduced reproductive rates. In waders of damp grassland, population declines have been driven mainly by land drainage and the associated intensification of grassland management. This has led to reduced reproductive success, as a result of lowered food availability, together with increased disturbance and trampling by farm stock, and in some localities increased nest predation. The external causal factors of population decline are known (with varying degrees of certainty) for all 30 species considered, and the demographic causal factors are known (again with varying degrees of certainty) for 24 such species. In at least 19 species, proposed causal factors have been tested and confirmed by experiment or by local conservation action, and 12 species have been shown to benefit (in terms of locally increased breeding density) from options available in one or more agri-environment schemes. Four aspects of agricultural change have been the main drivers of bird population declines, each affecting a wide range of species, namely: (1) weed-control, mainly through herbicide use; (2) the change from spring-sown to autumn-sown cereal varieties, and the associated earlier ploughing of stubbles and earlier crop growth; (3) land drainage and associated intensification of grassland management; and (4) increased stocking densities, mainly of cattle in the lowlands and sheep in the uplands. These changes have reduced the amounts of habitat and/or food available to many species. Other changes, such as the removal of hedgerows and ,rough patches', have affected smaller numbers of species, as have changes in the timings of cultivations and harvests. Although at least eight species have shown recent increases in their national population levels, many others seem set to continue declining, or to remain at a much reduced level, unless some relevant aspect of agricultural practice is changed. [source] National review of state wildlife action plans for Odonata species of greatest conservation needINSECT CONSERVATION AND DIVERSITY, Issue 2 2010JASON T. BRIED Abstract., 1.,The overarching goal of United States wildlife action plans is to prevent wildlife from becoming endangered or declining to levels where recovery becomes unlikely. Effective plan implementation depends on establishing Species of Greatest Conservation Need (SGCN), defined as wildlife species with small or declining populations or other characteristics that make them vulnerable. 2.,Although nearly two-thirds of distinct Odonata species known from the U.S. (441 species as of 2005) were appointed as SGCN, over half the states neglected to assign dragonfly SGCN, damselfly SGCN, or both. Western and southern states listed proportionately fewer odonate SGCN than states of the Great Lakes, Mid-Atlantic, and New England regions, apparently reflecting geographic patterns of legal authority, available information, and involvement by Odonata specialists. 3.,Greater consultation of Odonata specialists is encouraged in any revision of state wildlife action plans, along with increased: (i) use of existing conservation lists, (ii) inferences from field guides and major faunal synopses, (iii) recognition of patterns of endemism, and (iv) application of empirical species distribution modelling. 4.,Legal and management restrictions aside, insects and other invertebrates are often neglected in mainstream conservation efforts because they are perceived as understudied. It is erroneous to assume ,not enough information' exists for well-studied microfauna such as Odonata and doing so further undermines the conservation of less conspicuous and charismatic taxa. [source] No experimental evidence for local competition in the nestling phase as a driving force for density-dependent avian clutch sizeJOURNAL OF ANIMAL ECOLOGY, Issue 4 2009Marion Nicolaus Summary 1In birds, local competition for food between pairs during the nestling phase may affect nestling growth and survival. A decrease in clutch size with an increase in breeding density could be an adaptive response to this competition. To investigate whether breeding density causally affected the clutch size of great tits (Parus major), we manipulated breeding density in three out of eight study plots by increasing nest-box densities. We expected clutch size in these plots to be reduced compared to that in control plots. 2We analysed both the effects of variation in annual mean density (between-year comparisons) and experimental density (within-year comparison between plots) on clutch size variation, the occurrence of second broods and nestling growth. We examined within-female variation in clutch size to determine whether individual responses explain the variation over years. 3Over the 11 years, population breeding density increased (from 0·33 to 0·50 pairs ha,1) while clutch size and the occurrence of second broods decreased (respectively from 10·0 to 8·5 eggs and from 0·39 to 0·05), consistent with a negative density-dependent effect for the whole population. Nestling growth showed a declining but nonsignificant trend over years. 4The decline in population clutch size over years was primarily explained by changes occurring within individuals rather than selective disappearance of individuals laying large clutches. 5Within years, breeding density differed significantly between manipulated plots (0·16 pairs ha,1 vs. 0·77 pairs ha,1) but clutch size, occurrence of second broods and nestling growth were not affected by the experimental treatment, resulting in a discrepancy between the effects of experimental and annual variation in density on reproduction. 6We discuss two hypotheses that could explain this discrepancy: (i) the decline in breeding performance over time was not due to density, but resulted from other, unknown factors. (ii) Density did cause the decline in breeding performance, but this was not due to local competition in the nestling phase. Instead, we suggest that competition acting in a different phase (e.g. before egg laying or after fledgling) was responsible for the density effect on clutch size among years. [source] Comparative changes in adult vs. juvenile survival affecting population trends of African ungulatesJOURNAL OF ANIMAL ECOLOGY, Issue 4 2005NORMAN OWEN-SMITH Summary 1Among large mammalian herbivores, juvenile survival tends to vary widely and may thus have a greater influence on population dynamics than the relatively constant survival rates typical of adults. However, previous studies yielding stage-specific survival rates have been mostly on temperate zone ungulates and in environments lacking large predators. 2Annual censuses coupled with assessments of population structure enabled annual survival rates to be estimated for the juvenile, yearling and adult segments of nine ungulate species in South Africa's Kruger National Park. Four of these populations persisted at high abundance after initial increases (zebra, wildebeest, impala and giraffe), while five showed progressive declines during the latter part of the study period (kudu, waterbuck, warthog, sable antelope and tsessebe). 3The magnitude of the reduction in adult survival between periods showing contrasting population trends was similar to or greater than the corresponding change in juvenile survival for five of the nine species. Accordingly alterations in population phase, from increasing to stable or stable to declining, were brought about mostly through reduced survival within the adult segment. Elevated predation risk may have been responsible. 4Estimates were derived of the relative survival rates of juveniles, yearlings and adult segments associated with zero population growth, and the survival differential between adult males and females, for all nine species. Stage-specific survival rates appeared dependent on body mass, but with some anomalies. The sex difference in adult survival showed no obvious relation with sexual size dimorphism. 5For large mammalian herbivores, assessments of relative elasticities of stage-specific survival rates on population growth are problematic for several reasons. Sensitivity to corresponding increments in either survival or mortality rates provides a better basis for ecological or adaptive interpretation. Survival rates of adults seem to vary more over multiyear periods compared with mainly annual fluctuations in juvenile survival. More studies are needed on tropical species and in environments retaining large predators to support generalizations about factors influencing ungulate life-history patterns. [source] To go or not to go: Migration of human mesenchymal progenitor cells stimulated by isoforms of PDGFJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 5 2004Jörg Fiedler Abstract The recruitment of mesenchymal progenitor cells (MPCs) and their subsequent differentiation to osteoblasts is mandatory for bone development, remodeling, and repair. To study the possible involvement of platelet-derived growth factor (PDGF) isoforms, primary human MPCs and osteogenic differentiated progenitor cells (dOB) were examined for chemotaxic response to homodimeric human platelet-derived growth factor AA, -BB, and heterodimeric PDGF-AB. The role of PDGF receptors was addressed by preincubation with PDGF receptor alpha and beta chain specific antibodies. Migration of MPCs, dOB, and primary osteoblasts (OB) was stimulated by the addition of rhPDGF-AA, rhPDGF-BB, and rhPDGF-AB. The effect was highest in MPCs and for rhPDGF-BB, and declining with osteogenic differentiation. Preincubation with the receptor alpha specific antibody decreased the CI to borderline values while pretreatment with the receptor beta specific antibody led to a complete loss of chemotactic response to PDGF isoforms. In control experiments, basal migration values and rhBMP-2 as well as rxBMP-4 induced chemotaxis of MPC were not influenced by the addition of receptor alpha or beta antibodies. Interestingly, without preincubation the parallel exposure of MPC to rhTGF-,1 instantaneously leads to a selective loss of migratory stimulation by rhPDGF-AA. The chemotactic effect of PDGF isoforms for primary human MPCs and the influence of osteogenic differentiation suggest a functional role for recruitment of MPCs during bone development and remodeling. Moreover, these observations may be useful for novel approaches towards guided tissue regeneration or tissue engineering of bone. © 2004 Wiley-Liss, Inc. [source] Food Security in China and Contingency Planning: the Significance of Grain ReservesJOURNAL OF CONTINGENCIES AND CRISIS MANAGEMENT, Issue 3 2006Hendrik J. Bruins China is inhabited by ca 20 percent of the world population, but has only 7 percent of global arable land and only 6.6 percent of global freshwater resources. These unfavourable relationships between population size and the basic resources for food production , soil and water , require careful food security and contingency planning by the Chinese authorities. The country has been remarkably successful in raising its food production since 1949 at a faster rate (400 percent) than the increase in its population (240 percent). This has basically been achieved by increasing the yields per unit area with enhanced fertilizer use, as the total size of arable land has been decreasing in recent years. Though China attempts to be largely self-sufficient in food grain production, two possible contingency scenarios are suggested that might cause grave problems: (1) severe multi-annual drought; (2) reduced chemical fertilizer manufacturing. If Chinese food production would drop as a result by, say, 33 percent, famine, the dreaded scourge throughout Chinese history, might recur. A shortage of ca 150 million tons of food grains cannot easily be buffered by the volume of food grains annually traded on the world market, ca 240 million tons. Much of this amount tends to be committed already to traditional buyers, as most countries in the world have to import food grains. Cash reserves, therefore, may not guarantee food purchases, because global grain reserves are limited and declining. The formation and maintenance of large internal food grain reserves in China, common in its tradition and ancient history, seem the only realistic contingency planning strategy to avert famine in case of a severe decline in its food production in future crisis years. [source] Morphological features and clinical feasibility of thoracic duct: Detection with nonenhanced magnetic resonance imaging at 3.0 TJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2010Yu De-xin MD Abstract Purpose: To evaluate the detection of the thoracic duct using nonenhanced magnetic resonance imaging (MRI) and to determine the influence of some related disorders on the lymphatic duct. Materials and Methods: Highly fluid-sensitive sequence and fat-suppressed T2-weighted imaging (FS-T2WI) were performed in a total of 139 cases. The axial and coronal images were used to locate the thoracic duct and the measurement and evaluation of its dimensions were performed using a 3D maximum intensity projection (MIP) reconstruction image. The differences in the dimensions among control, portal hypertension, and common bile duct obstruction groups were compared using one-way analysis of variance. Results: The cisterna chyli was shown in 91% of cases on FS-T2WI, while the thoracic duct appeared in 70% of the MIP images. The common configuration of the cisterna chyli was tubular or saccular in 73%. Eighty thoracic ducts had a slight turn declining to the left at the level of T8,10. There was a significant difference in the transverse diameter of the thoracic duct between the portal hypertension group and other groups (F = 5.638, P = 0.005). Conclusion: Nonenhanced MRI is feasible for locating and depicting the morphological features of the thoracic duct. Portal hypertension may influence the dimension of the thoracic duct. J. Magn. Reson. Imaging 2010;32:94,100. © 2010 Wiley-Liss, Inc. [source] Characterization of viral kinetics in patients with hepatitis B e antigen-positive chronic hepatitis BJOURNAL OF MEDICAL VIROLOGY, Issue 6 2007I-Chin Wu Abstract A study was conducted during a 1 year follow-up to characterize the viral kinetics in hepatitis B e antigen (HBeAg)-positive chronic hepatitis B and to develop a model of predicting the probability of spontaneous HBeAg seroconversion. Fifty-seven patients with HBeAg-positive chronic hepatitis B were enrolled with monthly follow-ups from three Phase III clinical trial placebo groups. According to serial viral loads, 30 patients (52.6%) with the stationary pattern maintained stable HBV DNA levels with fluctuations of less than 1.5 log copies/ml. Twenty patients (35.1%) with the declining pattern exhibited a spontaneous decline of more than 1.5 log copies/ml without a following rebound of at least 1.5 log copies/ml. The remaining seven patients (12.3%) had the wavering pattern. Both declining and wavering patterns, when compared with the stationary pattern, had significantly higher hepatic necroinflammation in terms of ALT and Knodell scores at the baseline and peak ALT levels during the follow-up period. The declining pattern had a significantly better clinical outcome in terms of the lowest final HBV DNA and a reduction in the necroinflammatory score after 1 year. Furthermore, the declining pattern had a favorable HBeAg seroconversion rate (40%) compared with the wavering (14.3%) and stationary patterns (0%). A regression equation, incorporating simultaneous serum bilirubin, ALT, and HBV DNA levels, predicted the probability of HBeAg seroconversion with a sensitivity of 76.8% and a specificity of 74.7%. In conclusion, different viral kinetic patterns in patients with chronic hepatitis B implicate distinct clinical significance and immunologic perspective. J. Med. Virol. 79: 663,669, 2007. © 2007 Wiley-Liss, Inc. [source] Aging-dependent changes of microglial cells and their relevance for neurodegenerative disordersJOURNAL OF NEUROCHEMISTRY, Issue 5 2010Rommy Von Bernhardi J. Neurochem. (2010) 112, 1099,1114. Abstract Among multiple structural and functional brain changes, aging is accompanied by an increase of inflammatory signaling in the nervous system as well as a dysfunction of the immune system elsewhere. Although the long-held view that aging involves neurocognitive impairment is now dismissed, aging is a major risk factor for neurodegenerative diseases such as Alzheimer`s disease, Parkinson`s disease and Huntington's disease, among others. There are many age-related changes affecting the brain, contributing both to certain declining in function and increased frailty, which could singly and collectively affect neuronal viability and vulnerability. Among those changes, both inflammatory responses in aged brains and the altered regulation of toll like receptors, which appears to be relevant for understanding susceptibility to neurodegenerative processes, are linked to pathogenic mechanisms of several diseases. Here, we review how aging and pro-inflammatory environment could modulate microglial phenotype and its reactivity and contribute to the genesis of neurodegenerative processes. Data support our idea that age-related microglial cell changes, by inducing cytotoxicity in contrast to neuroprotection, could contribute to the onset of neurodegenerative changes. This view can have important implications for the development of new therapeutic approaches. [source] Trajectories of Prosocial Behavior and Physical Aggression in Middle Childhood: Links to Adolescent School Dropout and Physical ViolenceJOURNAL OF RESEARCH ON ADOLESCENCE, Issue 3 2006Katja Kokko Trajectories of prosocial behavior and physical aggression between 6 and 12 years of age were identified for a sample (N=1,025) of males. The trajectories were then used to predict school dropout and physical violence at age 17. Using a group-based semi-parametric method, two trajectories of prosociality (low and moderate declining) and three trajectories of physical aggression (low, moderate, and high declining) were obtained. Only a small minority (3.4%) of the boys were characterized by both high aggression and moderate prosociality. Physical aggression predicted both school dropout and physical violence, but contrary to expectations, prosocial behavior did not have additive or protective effects. [source] The development of early psychology of religion: A Dutch falsification of the received viewJOURNAL OF THE HISTORY OF THE BEHAVIORAL SCIENCES, Issue 3 2008Jacob A. Belzen This article takes issue with the received view of the history of the psychology of religion. Contrary to the presentation of "the" psychology of religion by Beit-Hallahmi in JHBS (1974) as declining after 1913, this article (1) states that the psychology of religion has never been a homogeneous enterprise, but rather a multiform one, with very different developments in different countries, and (2) presents the history of the Dutch Godsdienstpsychologische Studievereeniging [Study Association for the Psychology of Religion; GPSV] as one of the falsifications of the received view. The GPSV existed in the 1920s and as one of its most notable activities, it organized in 1926 the first international conference for the psychology of religion, an event described in some detail. © 2008 Wiley Periodicals, Inc. [source] Evaluation of residual values of different fertilisers at various rates used in phosphorus recapitalisation of an acid tropical soilJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2006Esther W Gikonyo Abstract The success of ,phosphorus (P) recapitalisation' depends on the changes in residual value (RV) over time. RVs of triple superphosphate (TSP), Gafsa phosphate rock (GPR) and Christmas Island phosphate rock (CIPR) were determined with and without manure bimonthly for 14 months. RV was calculated as the amount of previously applied fertiliser required to produce yield X divided by the amount of freshly applied TSP required to produce the same yield. Dry matter yield (DMY) response curves were curvilinear, with maximum DMY (11 t ha,1) occurring between 150 and 200 kg P ha,1 at 6 months and declining with time to 2,4 t ha,1 (14 months). Manure/fertiliser combinations increased DMY for CIPR but depressed DMY for TSP and GPR in all harvests except the first one. This can be attributed to nutrient imbalance caused by high P levels. RVs declined with time for fertilisers alone from 100,140% to 10,20% (14 months), while for fertiliser/manure combinations they declined from 110,180% to 10,20% (14 months). Increasing P rates from 100 to 300 kg P ha,1 resulted in the depression of initial RVs (100,140%) to 20,60% and later to 10,20% (14 months). Therefore P recapitalisation was not beneficial and hence annual P application would be recommended at 100,150 kg P ha,1. The phosphate rocks could effectively substitute for TSP. Copyright © 2006 Society of Chemical Industry [source] Feeding success of African wild dogs (Lycaon pictus) in the Serengeti: the effects of group size and kleptoparasitismJOURNAL OF ZOOLOGY, Issue 2 2005C. Carbone Abstract Longer-term ecosystem level dynamics are often neglected in conservation studies involving single species. In this study, a retrospective analysis is presented on the feeding performance of African wild dogs Lycaon pictus in the Serengeti in relation to a competing species, the spotted hyena Crocuta crocuta, to test whether hyenas had an effect on feeding performance of wild dogs in this ecosystem. Our analysis is based on observations of over 700 wild dog kills recorded over a 20-year period (from 1964 to 1987) during which time there was a decline in wild dog numbers (ending with their local extinction in 1991) and a twofold increase in hyena density. Overall, the amount of time that dogs had access to the kill (access time) decreased with increasing numbers of hyenas attending kills, but access time increased with increasing hunting-group size of dogs and carcass mass. In addition, in the 1980s, dogs spent longer at kills than in the 1970s for a given set of conditions, including when hyenas were absent. Our analysis demonstrates a greater potential for group benefits than was found in a previous study (Carbone, Du Toit et al., 1997). Hunting-group sizes of between two and six dogs performed best when hyenas attended dog kills because the benefits of increased defence outweighed the costs of having to share the carcass with more dogs. Hunting-group sizes of wild dog and levels of hyena attendance at the kill broadly paralleled the population trends in these species, with hunting-group sizes of wild dog declining, followed by hyena attendance increasing. Despite the combined effects of increased hyena attendance and reduced hunting-group size, dogs in the 1980s typically spent longer feeding and consumed more of the carcass including the poorest sections. This suggests that dogs in the 1980s may have been under greater energetic stress. [source] Forests, marketization, livelihoods and the poor in the Lao PDRLAND DEGRADATION AND DEVELOPMENT, Issue 2 2006J. D. Rigg Abstract The Lao PDR is making the transition from subsistence to cash, and command to market. Rural communities are being drawn ever more tightly into the embrace of the market economy and of the central state. The construction of roads, schools and health centres, the provision of credit and new crops and technologies, and the arrival of traders and the panoply of the consumer economy are all, in their different ways, remoulding rural economy and society. This paper looks at one aspect of this multi-stranded process of agrarian transformation: the role and place of forests and, in particular, non-timber forest products, in rural people's lives and livelihoods. The paper highlights the contradictory and uneven livelihood-eroding/enhancing effects of these transformations. In many upland areas of Laos livelihoods are being squeezed from ,below' by environmental degradation and from ,above' by the operation of government policies and, more generally, by evolving market relations. While market pessimists see market integration as a largely destructive process, the paper highlights the opportunities that market integration can provide through diversification and livelihood reorientation. The challenge is that these opportunities are unequally available and are likely to promote social differentiation. Some households find themselves in a position to embrace new opportunities while others are forced to continue to rely on a declining and degrading forest resource. Copyright © 2006 John Wiley & Sons, Ltd. [source] Is the prevalence of asthma declining?ALLERGY, Issue 2 2010Systematic review of epidemiological studies To cite this article: Anandan C, Nurmatov U, van Schayck OCP, Sheikh A. Is the prevalence of asthma declining? Systematic review of epidemiological studies. Allergy 2010; 65: 152,167. Abstract Asthma prevalence has increased very considerably in recent decades such that it is now one of the commonest chronic disorders in the world. Recent evidence from epidemiological studies, however, suggests that the prevalence of asthma may now be declining in many parts of the world, which, if true is important for health service planning and also because this offers the possibility of generating and testing new aetiological hypotheses. Our objective was to determine whether the prevalence of asthma is declining worldwide. We undertook a systematic search of EMBASE, Medline, Web of Science and Google Scholar, for high quality reports of cohort studies, repeat cross-sectional studies and analyses of routine healthcare datasets to examine international trends in asthma prevalence in children and adults for the period 1990,2008. There were 48 full reports of studies that satisfied our inclusion criteria. The large volume of data identified clearly indicate that there are, at present, no overall signs of a declining trend in asthma prevalence; on the contrary, asthma prevalence is in many parts of the world still increasing. The reductions in emergency healthcare utilization being reported in some economically developed countries most probably reflect improvements in quality of care. There remain major gaps in the literature on asthma trends in relation to Africa and parts of Asia. There is no overall global downward trend in the prevalence of asthma. Healthcare planners will for the foreseeable future, therefore, need to continue with high levels of anticipated expenditure in relation to provision of asthma care. [source] | |||||||||||||||||||||||||||||||||||||||||||