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Studies Demonstrating (studies + demonstrating)
Selected AbstractsIndividual Male Calling Pattern and Male Mating Success in the European Treefrog (Hyla arborea): Is there Evidence for Directional or Stabilizing Selection on Male Calling Behaviour?ETHOLOGY, Issue 2 2006Thomas W.P. Friedl In anurans, call properties are commonly classified based on within-male variability as being either static or dynamic. Numerous playback experiments in the laboratory have indicated that female preferences based on dynamic call properties are usually strongly directional, while female preferences based on static call properties are often stabilizing or weakly directional. However, there are only few studies demonstrating that female preferences for high values of dynamic call properties indeed exert directional selection on male calling behaviour in natural populations. Moreover, field studies investigating whether female preferences for values of static call properties around the mean of the population lead to currently operating stabilizing selection on male calling patterns in natural populations are completely lacking. Here I investigate for two consecutive breeding seasons male calling patterns and male mating success in a population of individually marked European treefrogs (Hyla arborea), a hylid frog with prolonged breeding season and a lek mating system. Individual male calling pattern as analysed in terms of seven temporal and spectral call properties did not differ between males that survived from one breeding season to the next and those not surviving. None of the seven call properties investigated differed significantly between mated and unmated males, indicating that there is no strong directional selection on male calling behaviour in the study population. However, in one study season males that produced calls with a number of pulses around the mean of the population were significantly more likely to obtain matings than males that produced calls with a number of pulses at the low or high end of the distribution. Thus, this study provides preliminary evidence for the operation of stabilizing selection on a static call property (i.e. the number of pulses per call) in a natural population of an anuran amphibian. [source] Open versus laparoscopic resection for liver tumoursHPB, Issue 6 2009Thomas Van Gulik Abstract Background:, The issue under debate is whether laparoscopic liver resections for malignant tumours produce outcomes which are comparable with conventional, open liver resections. Methods:, Literature review on liver resection and laparoscopy. Results:, There are no randomized controlled trials (RCTs) published that provide any evidence for the benefits of laparoscopic liver resections for liver tumours. In case,control series reporting short-term outcomes, laparoscopic liver resection has been shown to have the advantage of a reduced length of hospital stay. There are as yet, however, no adequate long-term survival studies demonstrating that laparoscopic liver resection is oncologically equivalent to open resection. Discussion:, The challenge for the near future is to test the oncological integrity of laparoscopic liver resection in controlled trials in the same way that we have learned from the RCTs carried out in laparoscopic resection for colorectal cancer. It is likely that laparoscopic liver resection will then have to compete with fast-track, open liver resection. Already, concerns have been raised regarding the learning curve required to master the techniques of laparoscopic liver resection. [source] In silico analysis of missense substitutions using sequence-alignment based methods,HUMAN MUTATION, Issue 11 2008Sean V. Tavtigian Abstract Genetic testing for mutations in high-risk cancer susceptibility genes often reveals missense substitutions that are not easily classified as pathogenic or neutral. Among the methods that can help in their classification are computational analyses. Predictions of pathogenic vs. neutral, or the probability that a variant is pathogenic, can be made based on: 1) inferences from evolutionary conservation using protein multiple sequence alignments (PMSAs) of the gene of interest for almost any missense sequence variant; and 2) for many variants, structural features of wild-type and variant proteins. These in silico methods have improved considerably in recent years. In this work, we review and/or make suggestions with respect to: 1) the rationale for using in silico methods to help predict the consequences of missense variants; 2) important aspects of creating PMSAs that are informative for classification; 3) specific features of algorithms that have been used for classification of clinically-observed variants; 4) validation studies demonstrating that computational analyses can have predictive values (PVs) of ,75 to 95%; 5) current limitations of data sets and algorithms that need to be addressed to improve the computational classifiers; and 6) how in silico algorithms can be a part of the "integrated analysis" of multiple lines of evidence to help classify variants. We conclude that carefully validated computational algorithms, in the context of other evidence, can be an important tool for classification of missense variants. Hum Mutat 29(11), 1327,1336, 2008. © 2008 Wiley-Liss, Inc. [source] Self,Other Agreement: Comparing its Relationship with Performance in the U.S. and EuropeINTERNATIONAL JOURNAL OF SELECTION AND ASSESSMENT, Issue 1 2005Leanne Atwater The use of multi-source feedback has proliferated in the United States in recent years; however, its usefulness in other countries is unknown. Using a large sample of American managers (n=3793), this study first replicated earlier studies demonstrating that simultaneous consideration of self and other ratings of leadership skills is important for managerial performance ratings. In addition, the impact of self,other agreement on performance was investigated among 2732 managers in five European countries (U.K., Germany, France, Denmark, Italy). Results indicated that the effect of self and other ratings in the prediction of performance differs between the U.S. and the European countries in that the simultaneous inclusion of both self and other ratings is generally less useful in those countries than in the U.S. Further, the effect of self,other agreement varies among the European countries. Implications for multi-source feedback interventions as well as multi-national personnel management are discussed. [source] The influence of parental behavior on vulnerability to nest predation in tropical thrushes of an Andean cloud forestJOURNAL OF AVIAN BIOLOGY, Issue 6 2009Konrad Halupka The Skutch hypothesis predicts that parental activity around the nest may attract the attention of predators and thus, in the tropics where predation pressure may be high, selection favors reduced parental activity. This hypothesis has been questioned by studies demonstrating that parents can decrease the risk of nest predation through nest defense. The link between parental activity and predation risk may be further confounded by nest site characteristics. We examined the effects of parental behavior and nest site on clutch survival in two sympatric tropical thrushes (Myadestes ralloides and Turdus leucops). We compared survival rates of clutches in three treatments: 1) natural nests at the incubation stage, 2) unattended nests (un-manipulated nests of the same species, with clutches unattended by parents), and 3) exposed clutches (eggs exposed in unconcealed positions, unprotected by the nest). Parental activity had a positive effect on clutch survival, which was revealed by significantly higher survival rate of clutches in attended nests compared to unattended nests. The effect of nest site was less clear: clutches in unattended natural nests survived better than clutches in exposed sites selected by humans, but results were insignificant. We propose that parent birds can exclude a group of opportunistic predators, that are able to destroy unattended clutches. Nest site characteristics may be less important in determining clutch survival in the tropics, where predator guilds are more diverse, making completely safe sites difficult to find. Our results challenge Skutch's hypothesis and point to the need for more data from tropical latitudes. [source] Applying wikis to managing knowledge,A socio-technical approachKNOWLEDGE AND PROCESS MANAGEMENT: THE JOURNAL OF CORPORATE TRANSFORMATION, Issue 1 2009Miia Kosonen As organizations are increasingly moving towards geographically dispersed and virtual forms of collaboration, knowledge sharing through social software such as wikis is widely acknowledged as an important area of research and practice. However, social software remains an under-investigated issue in the literature on knowledge management (KM), and there is a lack of studies demonstrating how organizations can successfully incorporate these technologies into their everyday operations. To bridge this gap, our paper examines a case of successful wiki implementation. We claim that understanding the implementation of wikis requires a socio-technical perspective focusing on the organizational context and activity system in which they are implemented rather than on their technological proficiency. Furthermore, we claim that their implementation brings about change in existing social systems, and results in new kinds of social constellations, interactions, and identities, which are manageable and controllable only to a limited extent. Copyright © 2009 John Wiley & Sons, Ltd. [source] How children and adults learn to use computers: A developmental approachNEW DIRECTIONS FOR CHILD & ADOLESCENT DEVELOPMENT, Issue 105 2004Zheng Yan How do children and adults learn to use computers? What developmental processes are involved in learning to use computers? This chapter reviews current understanding of these issues and presents empirical studies demonstrating how to advance that understanding. [source] Toxocara seropositivity in Sri Lankan children with asthmaPEDIATRICS INTERNATIONAL, Issue 2 2009Deepika Fernando Abstract Background:, Toxocariasis occurs in humans due to infection with Toxocara canis or T. cati, the nematode parasites of dogs and cats, respectively. The relationship between toxocariasis and asthma is complex, with some studies demonstrating that children with asthma were more likely to be Toxocara seropositive as compared to non-asthmatic children, and other studies indicating no such significant relationship. The aim of the present study was to investigate Toxocara seropositivity and its association with asthma in a selected group of Sri Lankan children. Methods:, Two groups of children were studied: group 1 included 100 children with confirmed bronchial asthma who were on regular inhaler steroid treatment for asthma; group 2 included 96 children who did not have physician-diagnosed asthma or upper respiratory tract infections, attending the same hospital. Diagnosis of Toxocara seropositivity was based on IgG Toxocara Microwell Serum Elisa Kits. Enzyme-linked immunosorbent assay was regarded as positive for a reading of 0.3 optical density units. Stool samples were examined for helminth ova. Results:,Toxocara seropositivity in children with asthma was 29% and this was significantly more than Toxocara seropositivity among non-asthmatic children (P < 0.001). Toxocara seropositivity was identified as a significant risk factor of asthma in a univariate model. Eosinophilia was seen in a significantly higher proportion of non-asthmatic and asthmatic children who were Toxocara seropositive. Toxocara seropositivity, however, was not identified as a significant risk factor in a multivariate model. Conclusions:, The analysis confirmed previously identified risk factors for asthma but there was no association between the helminth parasitic infection, toxocariasis and bronchial asthma in children. [source] Promoting evidence-based psychosocial care for cancer patients,PSYCHO-ONCOLOGY, Issue 1 2009Paul B. Jacobsen Abstract With numerous studies demonstrating that psychosocial care reduces distress and improves quality of life, practitioners have an obligation to treat cancer patients in a manner consistent with this evidence. Although the rationale is straightforward, major challenges exist in achieving the goal of translating research into clinical practice. One challenge has been the nature of the evidence, with many studies of psychosocial interventions characterized by poor methodological quality, absence of eligibility criteria specifying heightened distress, and minimal consideration of dissemination potential. A second challenge has been to make practitioners aware of relevant evidence. Targeted efforts at dissemination, such as the issuance of clinical practice guidelines and evidence-based recommendations and the distribution of intervention materials via the Internet, appear to be more effective than passive efforts in providing practitioners with useful information. Perhaps the most challenging aspect has been to persuade practitioners to change how they practice. One approach currently under development would allow practitioners and health-care organizations to perform self-evaluations of the quality of their psychosocial care based on review of medical records. Feedback showing quality of care to be less than optimal is likely to motivate change, especially if the quality indicators assessed are considered to be important and reliable and point to specific actions that can be taken. The use of evidence to promote changes in clinical practice represents one of the major ways in which the field of psycho-oncology can fully realize its potential to positively affect the lives of people with cancer. Copyright © 2008 John Wiley & Sons, Ltd. [source] The ,microflora hypothesis' of allergic diseasesCLINICAL & EXPERIMENTAL ALLERGY, Issue 12 2005M. C. Noverr Summary Increasingly, epidemiologic and clinical data support the hypothesis that perturbations in the gastrointestinal (GI) microbiota because of antibiotic use and dietary differences in ,industrialized' countries have disrupted the normal microbiota-mediated mechanisms of immunological tolerance in the mucosa, leading to an increase in the incidence of allergic airway disease. The data supporting this ,microflora hypothesis' includes correlations between allergic airway disease and (1) antibiotic use early in life, (2) altered fecal microbiota and (3) dietary changes over the past two decades. Our laboratory has recently demonstrated that mice can develop allergic airway responses to allergens if their endogenous microbiota is altered at the time of first allergen exposure. These experimental and clinical observations are consistent with other studies demonstrating that the endogenous microbiota plays a significant role in shaping the development of the immune system. Data are beginning to accumulate that a ,balanced' microbiota plays a positive role in maintaining mucosal immunologic tolerance long after post-natal development. Other studies have demonstrated that even small volumes delivered to the nasopharynx largely end up in the GI tract, suggesting that airway tolerance and oral tolerance may operate simultaneously. The mechanism of microbiota modulation of host immunity is not known; however, host and microbial oxylipins are one potential set of immunomodulatory molecules that may control mucosal tolerance. The cumulative data are beginning to support the notion that probiotic and prebiotic strategies be considered for patients coming off of antibiotic therapy. [source] | ||||||||||||||||