Negative Relationships (negative + relationships)

Distribution by Scientific Domains


Selected Abstracts


Effects of land use on aquatic macrophyte diversity and water quality of ponds

FRESHWATER BIOLOGY, Issue 4 2010
MUNEMITSU AKASAKA
Summary 1. Aquatic macrophyte diversity and water quality of 55 ponds in western Japan were related to land use and morphometric variables to identify the environmental factors that sustain biodiversity and the spatial extent at which these factors operate. 2. The relevant spatial extent for floating-leaved macrophyte richness (500 m from pond edge) was larger than that for submerged macrophyte occurrence (10, 75 and 100 m), whereas emergent macrophyte richness was best explained at much larger extents (1000 m). Total macrophyte richness was explained at the extent of 500, 750 and 1000 m. The extents relevant for explaining the physicochemical condition of pond water (100 and 250 m) were similar to those for submerged and floating-leaved macrophytes, suggesting that these two growth forms are more sensitive to water quality compared to emergent macrophytes. 3. Diversity of all three growth forms and that of total macrophytes collectively were inversely related to turbidity and nutrient concentration; among the three growth forms, submerged macrophytes were most affected by water quality. 4. Negative relationships were found between the proportion of urban area and the diversity of the three growth forms and that of total macrophytes and water quality. Species richness of emergent, floating-leaved and total macrophytes decreased with depth and increased with surface area up to about 5000 m2, above which it declined. 5. Urbanisation and enlargement of ponds were the two main factors that decreased aquatic macrophyte diversity in irrigation ponds. To alleviate the adverse effects of urban areas on aquatic macrophyte diversity, our results suggest that management efforts should focus on the creation of buffer zones within the relevant spatial extent from the pond edge. [source]


Latitudinal patterns in the phenological responses of leaf colouring and leaf fall to climate change in Japan

GLOBAL ECOLOGY, Issue 4 2008
Hideyuki Doi
ABSTRACT Aim, To estimate the potential effect of global climate change on the phenological responses of plants it is necessary to estimate spatial variations at larger scales. However, previous studies have not estimated latitudinal patterns in the phenological response directly. We hypothesized that the phenological response of plants varies with latitude, and estimated the phenological response to long-term climate change using autumn phenological events that have been delayed by recent climate change. Location, Japan. Methods, We used a 53-year data set to document the latitudinal patterns in the climate responses of the timing of autumn leaf colouring and fall for two tree species over a wide range of latitudes in Japan (31 to 44° N). We calculated single regression slopes for leaf phenological timing and air temperature across Japan and tested their latitudinal patterns using regression models. The effects of latitude, time and their interaction on the responses of the phenological timings were also estimated using generalized linear mixed models. Results, Our results showed that single regression slopes of leaf phenological timing and air temperature in autumn were positive at most stations. Higher temperatures can delay the timing of leaf phenology. Negative relationships were found between the phenological response of leaves to temperature and latitude. Single regression slopes of the phenological responses at lower latitudes were larger than those at higher latitudes. Main conclusions, We found negative relationships between leaf phenological responsiveness and latitude. These findings will be important for predicting phenological timing with global climate change. [source]


Relationship between soil nutrient availability and plant species richness in a tropical semi-arid environment

JOURNAL OF VEGETATION SCIENCE, Issue 6 2006
Yareni Perroni-Ventura
Abstract Question: What is the relationship between soil fertility and plant species richness in the ,fertile islands' occurring beneath two species of legume (Cercidium praecox and Prosopis laevigata)? Location: Tehuacán-Cuicatlán region, central Mexico. Methods: Plant richness was measured in three micro-environments (below canopies of C. praecox, below canopies of P. laevigata and in areas without canopies). The concentration of soil nutrients (C, N and P), C and N in the microbiota, and processes of ecosystem functioning (net C mineralization rate and N mineralization) were measured. The relationship between soil variables and plant richness were assessed with ANCOVAs. Results: Soil nutrients and species richness increases markedly under fertility islands. There were higher concentrations of C and N in the soil, faster rates of C mineralization, and higher species richness under P. laevigata canopies. The relationship between soil fertility and species richness was always positive except for total N, ammonium and net C mineralization rate under C. praecox, and for available P under P. laevigata. Conclusions: The sign of the relationship between soil fertility and species richness varies according to the nutrient and the micro-environment. Positive relationships could result from between species complementarity and facilitation. Negative relationships could be explained by a specific limitation threshold for some soil resources (P and N for plants and C for the soil microbiota) which eliminate the possibilities of between species complementarity and facilitation above that threshold. As in all observational studies, these relationships should be considered only correlational. [source]


Cytotoxic effects induced by hexachlorobenzene in Squilla mantis (L.) (Crustacea, Stomatopoda)

ENVIRONMENTAL TOXICOLOGY, Issue 1 2008
Antonio Dell'Anno
Abstract Contamination of marine environments by hexachlorobenzene (HCB) represents a serious concern for potential consequences on ecosystem and human health. Despite this, information on cytotoxic effects on marine organisms is still largely lacking. In this study, we investigated cytotoxic effects induced by HCB on gonads and muscular tissue of Squilla mantis by analysing Na+/K+ -ATPase activity and plasma membrane fluidity. This crustacean species was selected as a model for its habitat, trophic level, feeding behavior, and commercial exploitation for human consumption. Time course experiments revealed that low concentrations of HCB (i.e. 50 nM) determine an exponentially decrease of Na+/K+ -ATPase activity and a significant modification of cellular membrane fluidity. Significant negative relationships between Na+/K+ -ATPase activity and membrane fluidity were observed, suggesting that changes in the structure and packing of cellular membranes induced by HCB may be the primary factor affecting the activity of essential bilayer-associated enzymes. Overall these findings suggest that even small concentrations of HCB may determine important changes on cell metabolism with potential cascade effects on recruitment of this commercial species. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source]


Effects of floods versus low flows on invertebrates in a New Zealand gravel-bed river

FRESHWATER BIOLOGY, Issue 12 2006
ALASTAIR M. SUREN
Summary 1. Floods and low flows are hydrological events that influence river ecosystems, but few studies have compared their relative importance in structuring invertebrate communities. Invertebrates were sampled in riffles and runs at eight sites along 40 km of a New Zealand gravel-bed river every 1,3 months over 2.5 years, during which time a number of large flood and low flow events occurred. Flows were high in winter and spring, and low in summer and autumn. Four flow-related variables were calculated from hydrological data: flow on the day of sampling (Qsample), maximum and minimum flow between successive samples (Qmax and Qmin, respectively), and the number of days since the last bed-moving flood (Ndays). 2. The invertebrate community was summarised by relative densities of the 19 most abundant taxa and four biotic metrics [total abundance, taxon richness, the number of Ephemeroptera, Plecoptera and Trichoptera taxa (i.e. EPT richness), and per cent EPT]. Invertebrate density fluctuated greatly, and was high in summer and autumn, and low during winter and spring. Stepwise multiple regression (SMR) analysis was used to investigate relationships between the invertebrate community and season, flow, habitat and water temperature. 3. Seasonal variables were included in almost 50% of the SMR models, while flow-related variables were included in >75% of models. Densities of many taxa were negatively correlated to Qmin and Qmax, and positively correlated to Ndays, suggesting that while high flows reduced invertebrate densities, densities recovered with increasing time following a flood. Although season and flow were confounded in this study, many of the taxa analysed display little seasonal variation in abundance, suggesting that flow-related variables were more important in structuring communities than seasonal changes in density associated with life-cycles. 4. Five discrete flood and low flow events were identified and changes to invertebrate communities before and after these events examined. Invertebrate densities decreased more commonly after floods than after low flows, and there was a significant positive relationship between the number of taxa showing reductions in density and flood magnitude. Densities of most invertebrates either remained unchanged, or increased after low flow events, except for four taxa whose densities declined after a very long period (up to 9 months) of low flow. This decline was attributed to autogenic sloughing of thick periphyton communities and subsequent loss of habitat for these taxa. 5. Invertebrate communities changed more after floods and the degree of change was proportional to flood magnitude. Community similarity increased with increasing time since the last disturbance, suggesting that the longer stable flows lasted, the less the community changed. These results suggest that invertebrate communities in the Waipara River were controlled by both floods and low flows, but that the relative effects of floods were greater than even extended periods of extreme low flow. 6. Hydraulic conditions in riffles and runs were measured throughout the study. Riffles had consistently faster velocities, but were shallower and narrower than runs at all measured flows. Invertebrate density in riffles was expressed as a percentage of total density and regressed against the flow-related variables to see whether invertebrate locations changed according to flow. Significant negative relationships were observed between the per cent density of common taxa in riffles and Qsample, Qmax and Qmin. This result suggests either that these animals actively drifted into areas of faster velocity during low flows, or that their densities within riffles increased as the width of these habitats declined. [source]


Factors influencing the temporal coherence of five lakes in the English Lake District

FRESHWATER BIOLOGY, Issue 3 2000
D. G. George
1. The lakes in the Windermere catchment are all deep, glacial lakes but they differ in size, shape and general productivity. Here, we examine the extent to which year-to-year variations in the physical, chemical and biological characteristics of these lakes varied synchronously over a 30,40-year period. 2. Coherence was estimated by correlating time-series of the spring, summer, autumn and winter characteristics of five lakes: Esthwaite Water, Blelham Tarn, Grasmere and the North and South Basins of Windermere. Three physical, four chemical and two biological time-series were analysed and related to year-to-year variations in a number of key driving variables. 3. The highest levels of coherence were recorded for the physical and chemical variables where the average coherence was 0.81. The average coherence for the biological variables was 0.11 and there were a number of significant negative relationships. The average coherence between all possible lake pairs was 0.59 and average values ranged from 0.50 to 0.74. A graphical analysis of these results demonstrated that the coherence between individual lake pairs was influenced by the relative size of the basins as well as their trophic status. 4. A series of examples is presented to demonstrate how a small number of driving variables influenced the observed levels of coherence. These range from a simple example where the winter temperature of the lakes was correlated with the climatic index known as the North Atlantic Oscillation, to a more complex example where the summer abundance of zooplankton was correlated with wind-mixing. 5. The implications of these findings are discussed and a conceptual model developed to illustrate the principal factors influencing temporal coherence in lake systems. The model suggests that our ability to detect temporal coherence depends on the relative magnitude of three factors: (a) the amplitude of the year-to-year variations; (b) the spatial heterogeneity of the driving variables and (c) the error terms associated with any particular measurement. [source]


Latitudinal patterns in the phenological responses of leaf colouring and leaf fall to climate change in Japan

GLOBAL ECOLOGY, Issue 4 2008
Hideyuki Doi
ABSTRACT Aim, To estimate the potential effect of global climate change on the phenological responses of plants it is necessary to estimate spatial variations at larger scales. However, previous studies have not estimated latitudinal patterns in the phenological response directly. We hypothesized that the phenological response of plants varies with latitude, and estimated the phenological response to long-term climate change using autumn phenological events that have been delayed by recent climate change. Location, Japan. Methods, We used a 53-year data set to document the latitudinal patterns in the climate responses of the timing of autumn leaf colouring and fall for two tree species over a wide range of latitudes in Japan (31 to 44° N). We calculated single regression slopes for leaf phenological timing and air temperature across Japan and tested their latitudinal patterns using regression models. The effects of latitude, time and their interaction on the responses of the phenological timings were also estimated using generalized linear mixed models. Results, Our results showed that single regression slopes of leaf phenological timing and air temperature in autumn were positive at most stations. Higher temperatures can delay the timing of leaf phenology. Negative relationships were found between the phenological response of leaves to temperature and latitude. Single regression slopes of the phenological responses at lower latitudes were larger than those at higher latitudes. Main conclusions, We found negative relationships between leaf phenological responsiveness and latitude. These findings will be important for predicting phenological timing with global climate change. [source]


Hydrochemical behaviour of dissolved nitrogen and carbon in a headwater stream of the Canadian Shield: relevance of antecedent soil moisture conditions

HYDROLOGICAL PROCESSES, Issue 3 2008
Julie M. L. Turgeon
Abstract This paper examines the impact of contrasting antecedent soil moisture conditions on the hydrochemical response, here the changes in dissolved nitrogen (NO3,, NH4+ and dissolved organic nitrogen (DON)) and dissolved organic carbon (DOC) concentrations, of a first-order stream during hydrological events. The study was performed in the Hermine, a 5 ha forested watershed of the Canadian Shield. It focused on a series of eight precipitation events (spring, summer and fall) sampled every 2 or 3 h and showing contrasted antecedent moisture conditions. The partition of the eight events between two groups (dry or wet) of antecedent moisture conditions was conducted using a principal component analysis (PCA). The partition was controlled (first axis explained 86% of the variability) by the antecedent streamflow, the streamflow to precipitation ratio Q/P and by the antecedent groundwater depth. The mean H+, NO3,, NH4+, total dissolved nitrogen and DOC concentrations and electrical conductivity values in the stream were significantly higher following dry antecedent conditions than after wetter conditions had prevailed in the Hermine, although the temporal variability was high (17 to 138%). At the event scale, a significantly higher proportion of the changes in DON, NO3,, and DOC concentrations in the stream was explained by temporal variations in discharge compared with the seasonal and annual scales. Two of the key hydrochemical features of the dry events were the synchronous changes in DOC and flow and the frequent negative relationships between discharge and NO3,. The DON concentrations were much less responsive than DOC to changes in discharge, whereas NH was not in phase with streamflow. During wet events, the synchronicity between streamflow and DON or NO3, was higher than during dry events and discharge and NO3, were generally positively linked. Based on these observations, the hydrological behaviour of the Hermine is conceptually compatible with a two-component model of shallow (DON and DOC rich; variable NO3,) and deep (DON and DOC poor; variable NO3,) subsurface flow. The high NO3, and DOC levels measured at the early stages of dry events reflected the contribution from NO3, -rich groundwaters. The contribution of rapid surface flow on water-repellent soil materials located close to the stream channel is hypothesized to explain the DOC levels. An understanding of the complex interactions between antecedent soil moisture conditions, the presence of soil nutrients available for leaching and the dynamics of soil water flow paths during storms is essential to explain the fluxes of dissolved nitrogen and carbon in streams of forested watersheds. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Audit Quality, Corporate Governance, and Earnings Management: A Meta-Analysis

INTERNATIONAL JOURNAL OF AUDITING, Issue 1 2010
Jerry W. Lin
Earnings management is of great concern to corporate stakeholders. While numerous studies have investigated the effects of various corporate governance and audit quality variables on earnings management, empirical evidence is rather inconsistent. This meta-analysis identifies 12 significant relationships by integrating results from 48 prior studies. For corporate governance, the independence of the board of directors and its expertise have a negative relationship with earnings management. Similar negative relationships exist between earnings management and the audit committee's independence, its size, expertise, and the number of meetings. The audit committee's share ownership has a positive effect on earnings management. For audit quality, auditor tenure, auditor size, and specialization have a negative relationship with earnings management. Auditor independence, as measured by fee ratio and total fee, is also a deterrent to earnings management. [source]


Demands of immigration among Chinese immigrant nurses

INTERNATIONAL JOURNAL OF NURSING PRACTICE, Issue 5 2010
Amy X Ma DNP APRN-BC FNP
Ma AX, Quinn Griffin MT, Capitulo KL, Fitzpatrick JJ. International Journal of Nursing Practice 2010; 16: 443,453 Demands of immigration among Chinese immigrant nurses The purpose of this study was to identify the demands of immigration among Chinese nurses that have immigrated to the USA. The relationship between the demands of immigration and length of stay in the USA was investigated also. A descriptive correlational study design was used. A convenience sample of 128 nurses was recruited. A self-administered survey was conducted using the demands of immigration scale developed by Aroian, along with a demographic questionnaire. The results showed Chinese immigrant nurses have high demands of immigration. There were significant negative relationships between the demands of immigration and length of stay in the USA. Immigration demands decreased as length of stay increased but remained high even for those who had been in the USA for > 5 years. This information is vital to health-care agencies designing and implementing adaptation programmes targeting these demands to facilitate Chinese nurses' adaptation process. [source]


Importance of Perceived Personnel Selection System Fairness Determinants: Relations with Demographic, Personality, and Job Characteristics

INTERNATIONAL JOURNAL OF SELECTION AND ASSESSMENT, Issue 1-2 2004
Chockalingam Viswesvaran
This study explored the relative importance attached to various perceived personnel selection fairness determinants (e.g., selection system content-based variables, features of selection system administration). We investigated how demographic variables (ethnicity and gender), individual differences characteristics (the Big Five and cognitive ability) and job characteristics (job complexity and domestic/expatriate assignment status) relate to the importance of ratings of perceived personnel selection system determinants. The results, especially for race/ethnicity analyses indicated that there might be differences across demographic groups in importance placed on different aspects of selection system characteristics. The magnitudes of the relationships were small to moderate for Asian,White and Hispanic,White comparisons. Asian,Hispanic and gender differences in importance assessments were small. Few individual differences variables (i.e., personality and cognitive ability) were associated with importance placed on various aspects of selection system characteristics. Notable exceptions were moderate positive relationships between general mental ability and importance of content-based selection system characteristics, and moderate negative relationships between emotional stability, conscientiousness and cognitive ability, and importance of selection system context variables. The complexity levels of the jobs held by respondents did not appreciably affect the importance placed on the different selection system characteristics. There were few notable differences between importance assessments for domestic versus expatriate positions. Implications for practice, especially managing cultural diversity in organizations, and for theory development are discussed. [source]


Feeding ecology of wild migratory tunas revealed by archival tag records of visceral warming

JOURNAL OF ANIMAL ECOLOGY, Issue 6 2008
Sophie Bestley
Summary 1Seasonal long-distance migrations are often expected to be related to resource distribution, and foraging theory predicts that animals should spend more time in areas with relatively richer resources. Yet for highly migratory marine species, data on feeding success are difficult to obtain. We analysed the temporal feeding patterns of wild juvenile southern bluefin tuna from visceral warming patterns recorded by archival tags implanted within the body cavity. 2Data collected during 1998,2000 totalled 6221 days, with individual time series (n = 19) varying from 141 to 496 days. These data span an annual migration circuit including a coastal summer residency within Australian waters and subsequent migration into the temperate south Indian Ocean. 3Individual fish recommenced feeding between 5 and 38 days after tagging, and feeding events (n = 5194) were subsequently identified on 76·3 ± 5·8% of days giving a mean estimated daily intake of 0·75 ± 0·05 kg. 4The number of feeding events varied significantly with time of day with the greatest number occurring around dawn (58·2 ± 8·0%). Night feeding, although rare (5·7 ± 1·3%), was linked to the full moon quarter. Southern bluefin tuna foraged in ambient water temperatures ranging from 4·9 °C to 22·9 °C and depths ranging from the surface to 672 m, with different targeting strategies evident between seasons. 5No clear relationship was found between feeding success and time spent within an area. This was primarily due to high individual variability, with both positive and negative relationships observed at all spatial scales examined (grid ranges of 2 × 2° to 10 × 10°). Assuming feeding success is proportional to forage density, our data do not support the hypothesis that these predators concentrate their activity in areas of higher resource availability. 6Multiple-day fasting periods were recorded by most individuals. The majority of these (87·8%) occurred during periods of apparent residency within warmer waters (sea surface temperature > 15 °C) at the northern edge of the observed migratory range. These previously undocumented nonfeeding periods may indicate alternative motivations for residency. 7Our results demonstrate the importance of obtaining information on feeding when interpreting habitat utilization from individual animal tracks. [source]


Host sex and ectoparasites choice: preference for, and higher survival on female hosts

JOURNAL OF ANIMAL ECOLOGY, Issue 4 2007
PHILIPPE CHRISTE
Summary 1Sex differences in levels of parasite infection are a common rule in a wide range of mammals, with males usually more susceptible than females. Sex-specific exposure to parasites, e.g. mediated through distinct modes of social aggregation between and within genders, as well as negative relationships between androgen levels and immune defences are thought to play a major role in this pattern. 2Reproductive female bats live in close association within clusters at maternity roosts, whereas nonbreeding females and males generally occupy solitary roosts. Bats represent therefore an ideal model to study the consequences of sex-specific social and spatial aggregation on parasites' infection strategies. 3We first compared prevalence and parasite intensities in a host,parasite system comprising closely related species of ectoparasitic mites (Spinturnix spp.) and their hosts, five European bat species. We then compared the level of parasitism between juvenile males and females in mixed colonies of greater and lesser mouse-eared bats Myotis myotis and M. blythii. Prevalence was higher in adult females than in adult males stemming from colonial aggregations in all five studied species. Parasite intensity was significantly higher in females in three of the five species studied. No difference in prevalence and mite numbers was found between male and female juveniles in colonial roosts. 4To assess whether observed sex-biased parasitism results from differences in host exposure only, or, alternatively, from an active, selected choice made by the parasite, we performed lab experiments on short-term preferences and long-term survival of parasites on male and female Myotis daubentoni. When confronted with adult males and females, parasites preferentially selected female hosts, whereas no choice differences were observed between adult females and subadult males. Finally, we found significantly higher parasite survival on adult females compared with adult males. 5Our study shows that social and spatial aggregation favours sex-biased parasitism that could be a mere consequence of an active and adaptive parasite choice for the more profitable host. [source]


Evidence that dingoes limit abundance of a mesopredator in eastern Australian forests

JOURNAL OF APPLIED ECOLOGY, Issue 3 2009
Chris N. Johnson
Summary 1Aggressive behaviour of top predators may have strong effects on the distribution and abundance of mesopredator species. Such interactions between predator species can reduce the intensity of predation on vulnerable prey. Suppression of mesopredators by top predators is a potentially important process that could protect small prey species from unsustainable predation. 2There is some evidence that in Australia, the dingo Canis lupus suppresses populations of the red fox Vulpes vulpes. This interaction could be significant to biodiversity conservation because while dingoes have been in Australia for several thousand years and coexist with a wide range of small mammals, the fox is a recent arrival which has caused declines and extinctions, and continues to threaten many prey species. 3However the strength of the effect of dingoes on foxes is unclear, and some published data have been interpreted as demonstrating no relationship between abundance of the two species. These data come from forested habitats in eastern Australia, and may suggest that negative relationships of dingoes and foxes do not occur in complex habitats. 4We re-analyse published data on fox vs. wild dog (i.e. dingoes plus, potentially, feral dogs and hybrids) abundance in eastern forests. These data reveal a triangular relationship of fox to wild dog density: when wild dogs are abundant, foxes are consistently rare, while when wild dogs are rare, foxes may be abundant but are not always so. This suggests that the abundance of wild dogs sets an upper limit on the abundance of foxes, but does not fully determine fox abundance. 5Standard regression and correlation methods are not appropriate for analysing such triangular relationships. We apply two statistical methods that can be used to characterize the edges of data distributions, and use these to demonstrate a negative relationship of maximum fox abundance to the abundance of wild dogs. 6Synthesis and applications. Our analysis adds to evidence that dingoes may have negative effects on red foxes in a wide range of habitats, and therefore, that dingoes may be significant to conservation of mammal biodiversity in Australia. It also illustrates problems and solutions in the statistical analysis of abundance of one species as a function of the abundance of another species with which it has a strong interaction. [source]


Eucalyptus infestation by Leptocybe invasa in Uganda

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2009
Philip Nyeko
Abstract Very little is known about Leptocybe invasa Fisher & LaSalle, a new fast-spreading alien pest infesting Eucalyptus in several countries. This study examined L. invasa infestation on Eucalyptus germplasms in different agroecological zones of Uganda. The incidence and severity of the pest infestation were higher in hotter and drier agroecological zones than in cooler and wetter zones. There were direct negative relationships between altitude and L. invasa infestation on Eucalyptus species. No infestation was observed on any Eucalyptus species in stands at altitudes ranging from 1938 to 2452 (the maximum encountered) m above sea level. Leptocybe invasa infestation occurred on all Eucalyptus species encountered (Eucalyptus grandis, Eucalyptus camaldulensis, Eucalyptus saligna, Eucalyptus robusta), except Eucalyptus maidenii that escaped attack because it was located outside the ecological range of the insect. The incidence and severity of L. invasa infestation was generally higher on clonal hybrids E. grandis × E. camaldulensis than on E. grandis × Eucalyptus urophylla. Research on host germplasms, L. invasa biology and ecology, impact of the pest infestation and possible control strategies are suggested to facilitate the development of sustainable management strategies. Résumé On sait très peu de choses sur Leptocybe invasa Fisher & LaSalle, une nouvelle espèce nuisible très invasive qui infeste les Eucalyptus dans plusieurs pays. Cette étude a examiné l'infestation par L. invasa des germoplasmes d'Eucalyptus dans différentes zones agroécologiques d'Ouganda. L'occurrence et la gravité de l'infestation par cette espèce nuisible étaient plus élevées dans les zones agroécologiques plus chaudes et plus sèches que dans les zones plus fraîches et plus humides. Il y avait des relations négatives directes entre l'altitude et l'infestation des espèces d'eucalyptus par L. invasa. On n'a observé aucune infestation de quelque espèce d'eucalyptus que ce soit dans les plantations allant de 1938 à 2452 mètres d'altitude (la plus haute altitude à cet endroit). L'infestation par Leptocybe invasa touchait toutes les espèces d'eucalyptus rencontrées (Eucalyptus grandis, E. camaldulensis, E. saligna et E. robusta) à l'exception d'E. maidenii qui a échappéà cette attaque parce qu'il était situé en dehors de l'aire de dispersion écologique de cet insecte. L'occurrence et la gravité de l'infestation par cette espèce nuisible étaient plus élevées chez les hybrides clonés d'Eucalyptus grandis ×E. camaldulensis que chez les hybrides E. grandis × E. urophylla. Des recherches sur les germoplasmes hôtes, sur la biologie et l'écologie de L. invasa, sur l'impact de l'infestation par cette espèce nuisible et sur d'éventuelles stratégies de contrôle sont suggérées ici pour faciliter le développement de stratégies de gestion durables. [source]


The Application of Geographic Information Systems and Spatial Analysis to Assess Dumped and Subsequently Scattered Human Remains,

JOURNAL OF FORENSIC SCIENCES, Issue 3 2006
Mary H. Manhein M.A.
ABSTRACT: This study utilizes geographic information systems (GIS) and spatial analysis (SA) technology to address the problems associated with prediction of location and effective recovery of dumped and scattered human remains in Louisiana. The goals are to determine if a selective bias exists in Louisiana as to where and when human remains are dumped and to assess whether or not geographically specific patterns exist in the dispersal of human remains. We hypothesized that a positive relationship exists between postmortem interval (PMI) and dispersal distance, and that there are negative relationships between PMI and dispersal direction and between dispersal direction and distance. Our results indicate that, in Louisiana, remains are more often dumped in rural areas away from a structure, and are found within ¼ mile of the nearest road. For Louisiana, no seasonal bias was found in the analysis of when remains are dumped. Furthermore, with the exception of the relationship between PMI and the shortest distance remains were dispersed, no geographically specific patterns were detected in the analyses of dispersal distance, dispersal direction, and PMI. [source]


Narcissistic Subtypes and Contingent Self-Esteem: Do All Narcissists Base Their Self-Esteem on the Same Domains?

JOURNAL OF PERSONALITY, Issue 4 2008
Virgil Zeigler-Hill
ABSTRACT It has been suggested that there are two forms of narcissism: a grandiose subtype and a vulnerable subtype. Although these forms of narcissism share certain similarities, it is believed that these subtypes may differ in the domains upon which their self-esteem is based. To explore this possibility, the present study examined the associations between these narcissistic subtypes and domain-specific contingencies of self-worth. The results show that vulnerable narcissism was positively associated with contingencies of self-worth across a variety of domains. In contrast, the associations between grandiose narcissism and domain-specific contingencies of self-worth were more complex and included both positive and negative relationships. These results provide additional support for the distinction between grandiose and vulnerable narcissism by showing that the domains of contingent self-esteem associated with grandiose narcissism may be more limited in scope than those associated with vulnerable narcissism. [source]


The development of nurse-led suicide prevention training for multidisciplinary staff in a North Wales NHS Trust

JOURNAL OF PSYCHIATRIC & MENTAL HEALTH NURSING, Issue 2 2010
R. JONES rmn bsc msc
Accessible summary ,,Suicide and suicidal behaviour evoke strong feelings. That is so not only for those directly affected , the individual, family and friends, but for professional staff and the community at large. ,,Assessing the risk of suicide demands staff having the ability to connect and maintain rapport with people in varying degrees of distress. ,,Multidisciplinary training groups allow staff the opportunity to share their experiences and learn from one another. ,,Suicide awareness training for non mental health staff in the UK is variable and should be more of a priority. Abstract There are 300 deaths in Wales each year as a result of suicide. Though the rate in England and Wales has fallen in recent years, it is still the second most common cause of death in men aged 15,44 behind accidental death. The majority of those who die by suicide make contact with health professionals within a relatively short time before their death. For those with mental ill health, relationships with professionals appear particularly important; indeed negative relationships have been cited as a key factor precipitating death by suicide. This paper outlines a suicide awareness programme which aims to restate the values of empathy and relationship building in everyday interaction. It acknowledges risk factors and risk assessment tools, but more than anything strives to demonstrate the value of encouraging personal expression in patients. [source]


Parent , Adolescent Relationships and Girls' Unhealthy Eating: Testing Reciprocal Effects

JOURNAL OF RESEARCH ON ADOLESCENCE, Issue 4 2002
Andrea Bastiani Archibald
This longitudinal study tested the direction of associations between parent ,adolescent relationships and adolescent girls' unhealthy eating. Girls (N= 184) were seen at Time 1 (M age = 14.30 years), and then again 2 years later (Time 2; M age = 16.04 years). At both assessment periods, they completed measures that assessed their eating attitudes and behaviors, relationships with their parents, height, weight, and age of menarche. Whereas unhealthy family relationships have been hypothesized as a precursor to unhealthy eating attitudes and behaviors, it is also possible that increases in these behaviors contribute to more negative relationships within the family. Structural equation modeling was employed to simultaneously investigate the longitudinal influence of parent , adolescent relationships on girls' unhealthy eating, and girls' unhealthy eating on parent , adolescent relationships. The model was tested with the following controls: body mass (kg/m2), pubertal timing and age. A longitudinal direct effect was found for unhealthy eating on parent, adolescent relationships; however, no direct effect was found for parent, adolescent relationships on unhealthy eating over time. For middle, and late,adolescent girls, it appears that unhealthy eating behaviors and attitudes are predictive of less positive parent , adolescent relationships over time. [source]


Reliability and validity of the sexual pressure scale,

RESEARCH IN NURSING & HEALTH, Issue 4 2006
Rachel Jones
Abstract The purpose of this study was to develop the Sexual Pressure Scale (SPS) as a valid and reliable measure of gender stereotypical expectations to engage in sexual behavior. Data were collected using audio computer-assisted self-interview in 306 urban women, aged 18 to 29. Exploratory principal components analysis with varimax rotation yielded 19 items consisting of five factors: Condom Fear, Sexual Coercion, Women's Sex Role, Men Expect Sex, and Show Trust, accounting for 62% of the variance. Divergent and convergent validity were supported, respectively, by negative relationships of SPS factors with dyadic trust and positive relationships with sexual victimization and sexual risk behavior. Alpha reliability was .81; factor reliabilities ranged from .63 to .82. A valid assessment of sexual pressure can suggest the extent to which stereotypical gender expectations structure women's freedom to explore partner and condom use choices. © 2006 Wiley Periodicals, Inc. Res Nurs Health 29: 281,293, 2006. [source]


Management history and climate as key factors driving natterjack toad population trends in Britain

ANIMAL CONSERVATION, Issue 5 2010
A. L. McGrath
Abstract Along with other amphibian populations in Europe and elsewhere, natterjack toad Bufo calamita populations in Britain have declined since at least 1960. Conservation management since the 1970s has aimed to halt the decline and maintain viable populations at key sites throughout the species' recent historical range. Here, we assess population trends from 1985 to 2006 at 20 British B. calamita sites and evaluate the role of active management in maintaining good conservation status. We investigated the effects of 25 climatic, site-characteristic and conservation management variables on population trends using general linear models. In single-variable analyses, rainfall variables showed negative relationships with population trends. Among the site characteristics, being located at the very edge of the species' range (northern Irish Sea coast) and occurrence of common toad (B. bufo) were negatively related to B. calamita population trends. Management history (populations established via translocation as opposed to native populations) had a significant positive effect; as had sites that received greater translocation releases, undergone Species Recovery Programme management, and where common toad was absent. In multiple-variable analyses, the combined effects of management history and average pre-breeding season rainfall accounted for inter-site variation in population trends. The rainfall effects in single- and multiple-variable analyses were strongly influenced by three sites with very high rainfall whilst no clear effect was apparent for the remaining sites. This study highlights the role of climatic factors in population decline, and the importance of conservation management in stabilizing population trends. Climate change over the next 50,100 years is predicted to have limited impacts on most B. calamita populations in Britain, but strongly positive impacts on the most threatened populations located at the very edge of species' range that will benefit from reduced precipitation. A need for active conservation management will remain for the foreseeable future. [source]