bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nurse supervisors' actions in relation to their decision‐making style and ethical approach to clinical supervision
Authors: Berggren Ingela , Severinsson Elisabeth 
Published: March 2003

Aim. The aim of the study was to explore the decision‐making style and ethical approach of nurse supervisors by focusing on their priorities and interventions in the supervision process. Background. Clinical supervision promotes ethical awareness and behaviour in the nursing profession. Methods. A focus group comprised of four clinical nurse supervisors with considerable experience was studied using qualitative hermeneutic content analysis. Findings. The essence of the nurse supervisors' decision‐making style is deliberations and priorities. The nurse supervisors' willingness, preparedness, knowledge and awareness constitute and form their way of creating a relationship. The nurse supervisors' ethical approach focused on patient situations and ethical principles. The core components of nursing supervision interventions, as demonstrated in supervision sessions, are: guilt, reconciliation, integrity, responsibility, conscience and challenge. The nurse supervisors' interventions involved sharing knowledge and values with the supervisees and recognizing them as nurses and human beings. Conclusion. Nurse supervisors frequently reflected upon the ethical principle of autonomy and the concept and substance of integrity. The nurse supervisors used an ethical approach that focused on caring situations in order to enhance the provision of patient care. They acted as role models, shared nursing knowledge and ethical codes, and focused on patient related situations. This type of decision‐making can strengthen the supervisees' professional identity. The clinical nurse supervisors in the study were experienced and used evaluation decisions as their form of clinical decision‐making activity. The findings underline the need for further research and greater knowledge in order to improve the understanding of the ethical approach to supervision.
An Experimental study of reduced parental effort and future reproductive success in the puffin, Fratercula arctica
Authors: Wernham Christine V. , Bryant David M. 
Published: March 2003

1.  The puffin, a long‐lived seabird, was studied on the Isle of May, East Scotland between 1990 and 1992. During two of these years, parental effort was experimentally decreased by supplementary feeding of young. This aimed to identify inter‐year reproductive costs, and show whether they took the form of reduced adult survival, reduced fledging success and/or a reduction in the ‘quality’ of offspring in the following year. 2.  The feeding treatment significantly reduced the daily number of feeds delivered by experimental parents by 67% in 1990 and 87% in 1991. 3.  The proportions of experimental and control parents returning to the colony in the year following manipulation did not differ significantly, although in 1991, 2·5 times as many controls (young unfed) as experimental birds (young fed) failed to return. 4.  The fledging success of experimental pairs in the year following manipulation (68%) was significantly higher than that of controls (24%). 5.  Experimental pairs raised young with significantly higher body condition (Residual Peak Mass) than that of controls in the year following manipulation (1992). 6.  Experimental parents did not differ from controls in their body condition (Lipid Reserve Mass) or rate of reserve depletion, either in the year of manipulation or in the following breeding season; hence there was no evidence for a role of the measured component of body condition in the cost mechanism. 7.  The study demonstrated inter‐year reproductive costs for puffins and supported the hypothesis that long‐lived species reduce the ‘quality’ of their offspring or abandon a breeding attempt rather than compromise their survival and future opportunities to reproduce.
Winter herbivory by voles during a population peak: the relative importance of local factors and landscape pattern
Authors: HAMBÄCK PETER A. , SCHNEIDER MICHAEL , OKSANEN TARJA 
Published: March 2003

1.  We studied the relative role of local habitat variables and landscape pattern on vole–plant interactions in a system with grey‐sided voles (Clethrionomys rufocanus (Sund.)) and their favourite winter food plant, bilberry (Vaccinium myrtillus L.). The study was conducted during a vole peak year (1992–93) in a tundra area in northern Norway. 2.  Using Mantel statistics we were able to separate the direct effects of the spatial patterning of habitats and the indirect effects due to spatial aggregations of similar habitats. 3.  Results indicate that knowledge about the explicit spatial patterning of patches does not improve our understanding of the system. Instead, two local factors, vegetation height and bilberry biomass, explained more than 50% of the variation in cutting intensity in winter (defined as the proportion of above‐ground shoots cut). Increasing vegetation height increased, and increasing bilberry biomass decreased, the cutting intensity. 4.  The conclusion that grey‐sided voles are able to distribute themselves relative to habitat quality was also partially supported by our estimated over‐winter persistence by voles in the various habitats. Vole persistence was uncorrelated with vegetation height, the important predictor of autumn vole density, but tended to correlate with the deviation from the relation between vegetation height and autumn vole density. This conforms to the expectations from the theory of ideal‐free habitat distribution. 5.  The cue for vole habitat choice, i.e. vegetation height, indicates that either predation or freezing risk is important for voles when selecting over‐wintering habitat.
A seasonal shift in egg‐laying behaviour in response to cues of future competition in a treehole mosquito
Authors: Edgerly J. S. , Mcfarland M. , Morgan P. , Livdahl T. 
Published: March 2003

1. We tested a set of hypotheses to predict egg‐laying behaviour in Aedes triseriatus in the field in Massachusetts. These hypotheses reflect three main themes: females avoid competitive or predatory threats to their larvae; females judge larvae or eggs as cues to future permanence or productivity within a treehole; and females are either opportunistic ovipositors, or hedge their bets by scattering their eggs in multiple habitats. We predicted that mosquitoes might vary in their response depending on whether their offspring will hatch immediately or enter diapause and hatch the next year. 2. We stocked artificial treeholes with larvae at four densities ranging from 0 to 90 larvae per habitat for four trials in 1992 and eight trials in 1994. In 1992, we added predatory Anopheles barberi larvae to half the replicates of each density level. In 1994, we tested for an interaction between egg and larval density by stocking additional traps with eggs in batches of 0, 20 and 200, and larvae in densities as in the previous trials. 3. The population revealed a significant interaction between time of year and larval density. More eggs accumulated in traps stocked with fewer larvae (0 or 15) early in the season, but females showed a slight positive response to higher densities (45 or 90) later on, after their offspring were all likely to enter diapause. These results suggest that potential ambiguities of larval cues, with indications of habitat permanence as well as adversity of future competition, are resolved by females. Females did not respond differentially to the predatory Anopheles barberi larvae. 4. The estimated batch size obtained in oviposition traps did not differ from the fecundity of field‐caught females allowed to oviposit under confinement in laboratory vials, suggesting that bet‐hedging by scattering of eggs among multiple habitats did not occur. 5. An unexpected result, a positive response to higher egg densities, is discussed in light of studies on other insects. This result conflicts with our predictions based on females choosing less competitive environments for their larvae and also conflicts with previously published accounts of avoidance of eggs in this species. Preference for habitats with conspecific eggs might be explained if eggs reflect habitat stability or if larvae gain an advantage from being in an aggregation. Neither hypothesis is resolved by the present study.
Exploring stable pattern formation in models of tussock moth populations
Authors: Wilson William G. , Harrison Susan P. , Hastings Alan , Mccann Kevin 
Published: March 2003

1. The western tussock moth (Orgyia vetusta) at the University of California Bodega Marine Reserve (Sonoma County, California, USA) exhibits dense, localized populations in the midst of extensive habitats where variation in host plant quality or predator abundance is unable to explain the restricted extent of the outbreaks. 2. Two primary features suggest that the host patterning is intrinsically generated: (i) female tussock moths are wingless, producing a low effective dispersal distance for the hosts; and (ii) the tussock moth population is attacked by several species of widely dispersing wasp and fly parasitoids. 3. We consider a set of spatially explicit host–parasitoid models to examine whether intrinsically generated patterns are possible within this system. These models include a spatially extended Nicholson–Bailey model to examine general features of pattern formation in host–parasitoid systems, and two system‐specific models, an individual‐based simulation and a population‐level analytic model, to examine the details of this empirical system. 4. Both stable patterning and rapid extinction of the host population are initial‐condition dependent outcomes of the general and specific models, implying that an intrinsically generated stable host pattern is feasible within the tussock moth system. 5. Stable patterning is enhanced by a large parasitoid‐to‐host dispersal ratio, local host resource limitation, and increased parasitism at the host patch's edge.
Associations between parasitism and host genotype in natural populations ofDaphnia(Crustacea: Cladocera)
Authors: Little Tom J. , Ebert Dieter 
Published: March 2003

1. Numerous models of parasite−host coevolution have shown that parasitism could play a key role in a wide range of biological phenomena. One critical assumption underlying models of parasite−host coevolution is that natural selection acts on genetic variation for host susceptibility, but this assumption has rarely been tested in the wild.2.Clonal hosts are particularly suitable for detecting associations between genotypes and parasitism, because multi‐locus gene complexes are preserved during reproduction, and following clonal selection, hosts which differ at resistance loci may also show differences at neutral marker loci. In this study, allozymes were used to search for associations between multi‐locus host genotypes (clones) and parasitism within 25 cyclically parthenogenetic populations ofDaphnia.3.Rates of parasitism were observed ranging from 0% to 48% of adult females, and infection by microparasites was found to significantly reduce host fecundity.4.Significant differences were detected between the clonal composition of parasitized and healthyDaphniain 12 populations, showing that the proportion of individuals infected varies among clones. Six populations were sampled repeatedly to determine whether this variation was associated with temporal changes in both host clonal frequencies and population genetic characteristics (Hardy−Weinberg equilibrium, genotypic linkage disequilibrium). Three of the six temporally sampled populations showed changes in genetic structure that were consistent with the expectations of parasite‐mediated selection, while the other three did not. These latter three populations all had low parasite prevalence (indicating low selection intensities) and/or comprised primarily rare clones, thus limiting the statistical power of the study to detect parasite‐mediated effects.5.The results show the presence of genetic variation for the likelihood of contracting disease withinDaphniapopulations. These associations between infection and host genotype could result from genetic variation for parasite resistance or within‐pond spatial arrangement of both host genotypes and parasite prevalences. Either factor would lead to parasite‐mediated selection and the modulation of gene frequecies within populations.
Coexistence mechanisms of mycophagous drosophilids on multispecies fungal hosts: aggregation and resource partitioning
Authors: Toda Masanori J. , Kimura Masahito T. , Tuno Nobuko 
Published: March 2003

1. In nature various mechanisms that provide some refuges for inferior species to escape from competition act together to promote the species coexistence in a local community. We propose a method to evaluate simultaneously the relative importance of different mechanisms for the species coexistence, focusing on a mycophagous drosophilid community depending on a multispecies fungal host system, where two mechanisms – aggregation over patches of single fungal species and resource partitioning at the fungal species level – can act together. The data are based on the numbers of adult insects emerging from naturally occurring fungi collected from a temperate forest in northern Japan.2.We confirm the finding ofSevenster & van Alphen (1996)that large patches are low‐density refuges despite the large absolute numbers of competitors on them, and therefore adopt new measures for intra‐ and interspecific aggregations and the species‐persistence criterion, which were developed bySevenster (1996)to take account of variable patch sizes in calculating the aggregation measures.3.The calculated measures are compared among three analyses for fungal resources: AR‐analysis (the original data‐set from multispecies fungal patches) in which both aggregation and resource partitioning can act together; R‐analysis (combining the data for all patches of each fungal species) in which only resource partitioning at the fungal species level can act; and A‐analysis (calculating the measures independently for each fungal species) in which only aggregation process can act as a coexistence mechanism.4.Intraspecific aggregation over multispecies fungal patches is strengthened by both aggregation and resource partitioning processes.5.We reconfirm the finding ofSevenster & van Alphen (1996)that interspecific associations are consistent over years, and support their claim that such consistent associations should be taken as real aspects of the community structure.6.Measures for the persistence criterion (T), the ‘relative effect of competitor aggregation’, are less than unity, satisfying the necessary and sufficient condition for the species persistence, in most drosophilid species concerned; these tend to be smaller in AR‐analysis than in R‐ or A‐analysis, suggesting facilitation of the species coexistence by both aggregation and resource partitioning in the mycophagous drosophilid community studied.7.Differences inT‐value between AR‐ and R‐analyses and between AR‐ and A‐analyses may indicate relative contributions of aggregation and resource partitioning, respectively, to the species coexistence. We propose a method to compare various communities in a multi‐dimensional space with regard to the relative importance of different coexistence mechanisms.
Effects of experimental habitat fragmentation and connectivity on root vole demography
Authors: Ims Rolf A. , Andreassen Harry P. 
Published: March 2003

Summary 1. We used a factorial experimental design to test whether habitat fragmentation (two different fragment sizes) and connectivity (presence and absence of corridors between small fragments) affected population growth rate and two conventional measures of the demographic structure (proportion of reproductive adults and sex ratio) in 12 enclosed populations of root voles. 2. Because the matriline has been suggested to be a functional entity affecting the demography of Microtus populations, we employed a study protocol (including laboratory‐raised founder animals and intensive live trapping combined with fluorescent powder techniques), which enabled us to track the matrilineal genealogy in the populations. Thus, the effect of habitat structure on the matrilineal structure of the populations, quantified by the Shannon–Wiener diversity index, could be tested for the first time. 3. Population growth rate was density dependent, but neither this population parameter nor sex ratio and proportion of reproductive adults differed between the habitat treatments. This was unexpected since the presumed determinants of Microtus demography, such as individual space use, dispersal distances and spatio‐social organization had earlier been found to differ between the treatments. 4. The matrilineal structure (diversity) of the populations changed in response to the experimental habitat manipulations. In corridor‐connected systems, some matrilines became numerically dominant, which lead to reduced matrilineal diversity compared to systems with isolated habitat fragments. We hypothesize that some matrilines were able to colonize and exploit corridor‐connected fragments better than other matrilines. Matrilineal diversity was not related to any other demographic attribute (growth rate, sex ratio and functional stage structure) at the population level. 5. Our results suggest that fragmentation‐induced changes of individual and matrilineal level attributes do not necessarily propagate into population level differences in vital rates. The notion that matrilines may be a functional entity in Microtus populations could not be supported. 6. Our experimental results suggest that population genetics, more than population demography, may be sensitive to habitat fragmentation and connectivity, within the specific temporal and spatial extent explored. In particular, the effect of corridors on matrilineal diversity imply that population genetic studies based on mtDNA markers should consider habitat connectivity when analysing genetic diversity.
Are incubation and fledging periods longer in the tropics?
Authors: Geffen Eli , Yom‐Tov Yoram 
Published: March 2003

Summary1. It is commonly believed that the smaller clutch size of tropical compared with temperate birds is a response to a high predation rate. If this is true, one would expect incubation and fledging periods in the tropics to be shorter than in temperate regions, but they are generally thought to be longer in the tropics than in northern temperate areas.2. In this paper we show that among passerines in both the Old and the New World, there is little or no difference in either incubation or fledging periods between temperate and tropical areas.3. We suggest that tropical birds differ from temperate ones in their clutch size and extended post‐fledging periods, which is necessary for juvenile survival, but probably not in other life history parameters.
A state‐dependent model of activity patterns in homing limpets: balancing energy returns and mortality risks under constraints on digestion
Authors: Burrows Michael T. , Santini Giacomo , Chelazzi Guido 
Published: March 2003

Summary1. Different species of limpets, and different populations of the same species, show an impressive variation in temporal organization of foraging activity. Field studies also reveal different patterns of activity among individuals of the same population.2. Many hypotheses have been proposed to explain the observed behavioural patterns, in terms of effects of several biotic and abiotic factors acting in different tidal phases, yet without taking into account possible interactions among environmental and internal factors. Moreover, the importance of energy reserves and food processing has rarely been considered in this context.3. The role of different environmental factors and functional traits in shaping the organization of foraging of limpets at different time scales was analysed by using a state‐dependent optimal foraging model, based on stochastic dynamic programming. The model includes interaction among mortality risks and energy costs incurred during the different tidal phases, the effect of different levels of energy reserves, gut fullness and changing food availability.4. The model is able to reproduce a variety of foraging patterns with reference to the tidal cycle when changing combinations of values assigned to the risk of mortality, energy costs and food availability. The model also shows that the level of energy reserves, gut volume and rate of food processing can be of major importance in determining the short‐term organization of activity within each foraging phase.
Contrasting interference functions and foraging dispersion in two species of shorebird (Charadrii)
Authors: Yates Michael G. , Stillman Richard A. , Goss‐Custard John D. 
Published: March 2003

Summary1. Above a threshold density of ≈ 100 birds ha‐1, strong interference occurred between redshankTringa totanus(Linnaeus) feeding by sight on the amphipod crustaceanCorophium volutator(Pallas). No aggressive interactions occurred between the birds and the probable cause was prey depression.2. Redshank fed in a square metre of mud that had recently been exploited by another redshank much less often than would be expected by chance. By avoiding areas where prey would have been recently exploited, the feeding rate of redshank was up to three times faster than it would have been had they not avoided other foraging redshank.3. Bar‐tailed godwit fed in a square metre of mud that had been recently exploited by another godwit much more often than would be expected by chance in randomly moving birds. They tended to flock while foraging and showed no tendency to avoid areas where prey would have been recently exploited.4. There was no evidence that interference occurred between bar‐tailed godwitLimosa lapponica(Linnaeus) feeding on the polychaete lugwormArenicola marina(Linnaeus) at densities below 300 birds ha‐1, even though aggressive interactions occurred between birds.