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Separate Analyses (separate + analysis)
Selected AbstractsSpecies richness patterns and metapopulation processes , evidence from epiphyte communities in boreo-nemoral forestsECOGRAPHY, Issue 2 2006Swantje Löbel For several epiphyte species, dispersal limitation and metapopulation dynamics have been suggested. We studied the relative importance of local environmental conditions and spatial aggregation of species richness of facultative and obligate epiphytic bryophytes and lichens within two old-growth forests in eastern Sweden. The effect of the local environment was analyzed using generalized linear models (GLM). We tested whether species richness was spatially structured by fitting variogram models to the residuals of the GLM. In addition, we analyzed the species-area relationship (area=tree diameter). Different environmental variables explained the richness of different species groups (bryophytes vs lichens, specialists vs generalists, sexual vs asexual dispersal). In most groups, the total variation explained by environmental variables was higher than the variation explained by the spatial model. Spatial aggregation was more pronounced in asexually than in sexually dispersed species. Bryophyte species richness was only poorly predicted by area, and lichen species richness was not explained by area at all. Spatial aggregation may indicate effects of dispersal limitation and metapopulation dynamics on community species richness. Our results suggest that species groups differ in habitat requirements and dispersal abilities; there were indications that presence of species with different dispersal strategies is linked to the age of the host tree. Separate analyses of the species richness of species groups that differ in the degree of habitat specialization and dispersal ability give insights into the processes determining community species richness. The poor species-area relationship, especially in lichens, may indicate species turnover rather than accumulation during the lifetime of the host tree. Epiphyte species extinctions may be mainly caused by deterministic processes, e.g. changes in habitat conditions as the host tree grows, ages and dies, rather than by stochastic population processes. [source] Cytogenetic status in newborns and their parents in Madrid: The BioMadrid studyENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 4 2010Virginia Lope Abstract Monitoring cytogenetic damage is frequently used to assess population exposure to environmental mutagens. The cytokinesis-block micronucleus assay is one of the most widely used methods employed in these studies. In the present study we used this assay to assess the baseline frequency of micronuclei in a healthy population of father-pregnant woman-newborn trios drawn from two Madrid areas. We also investigated the association between micronucleus frequency and specific socioeconomic, environmental, and demographic factors collected by questionnaire. Mercury, arsenic, lead, and cadmium blood levels were measured by atomic absorption spectrometry. The association between micronucleated cell frequency and the variables collected by questionnaire, as well as, the risk associated with the presence of elevated levels of metals in blood, was estimated using Poisson models, taking the number of micronucleated cells in 1,000 binucleated cells (MNBCs) as the dependent variable. Separate analyses were conducted for the 110 newborns, 136 pregnant women, and 134 fathers in whom micronuclei could be assessed. The mean number of micronucleated cells per 1,000 binucleated cells was 3.9, 6.5, and 6.1 respectively. Our results show a statistically significant correlation in MNBC frequency between fathers and mothers, and between parents and newborns. Elevated blood mercury levels in fathers were associated with significantly higher MNBC frequency, compared with fathers who had normal mercury levels (RR:1.21; 95%CI:1.02,1.43). This last result suggests the need to implement greater control over populations which, by reason of their occupation or life style, are among those most exposed to this metal. Environ. Mol. Mutagen., 2010. © 2009 Wiley-Liss, Inc. [source] Comparing United States versus International Medical School Graduate Physicians Who Serve African- American and White ElderlyHEALTH SERVICES RESEARCH, Issue 6 2006Daniel L. Howard Objective. To examine the relationship that international medical school graduates (IMGs) in comparison with United States medical school graduates (USMGs) have on health care-seeking behavior and satisfaction with medical care among African-American and white elderly. Data Sources. Secondary data analysis of the 1986,1998 Piedmont Health Survey of the Elderly, Established Populations for the Epidemiological Study of the Elderly, a racially oversampled urban and rural cohort of elders in five North Carolina counties. Study Design. Primary focus of analyses examined the impact of the combination of elder race and physician graduate status across time using a linear model for repeated measures analyses and ,2 tests. Separate analyses using generalized estimating equations were conducted for each measure of elder characteristic and health behavior. The analytic cohort included 341 physicians and 3,250 elders (65 years old and older) in 1986; by 1998, 211 physicians and 1,222 elders. Data Collection/Extraction Methods. Trained personnel collected baseline measures on 4,162 elders (about 80 percent responses) through 90-minute in-home interviews. Principal Findings. Over time, IMGs treated more African-American elders, and those who had less education, lower incomes, less insurance, were in poorer health, and who lived in rural areas. White elders with IMGs delayed care more than those with USMGs. Both races indicated being unsure about where to go for medical care. White elders with IMGs were less satisfied than those with USMGs. Both races had perceptions of IMGs that relate to issues of communication, cultural competency, ageism, and unnecessary expenses. Conclusion. IMGs do provide necessary and needed access to medical care for underserved African Americans and rural populations. However, it is unclear whether concerns regarding cultural competency, communication and the quality of care undermine the contribution IMGs make to these populations. [source] The impact of the Occupation of Guernsey 1940,1945 on breast cancer risk factors and incidenceINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 6 2007I. S. Fentiman Summary To examine the impact of the German Occupation of Guernsey (1940,1945) on breast cancer risk factors and incidence. Under study were 1019 women who stayed, or whose mothers had stayed, in Guernsey, and 1358 women evacuated or born to evacuated mothers. Amongst those born 1926,1934 who remained in Guernsey, the secular trend of earlier menarche disappeared: menarche was delayed by 12 months for those born in 1930. By March 2006, 97 breast cancers had been diagnosed, 37 in the occupied group. Unusually, higher age at menarche appeared to be associated with increased risk of breast cancer (,14 years vs. ,13 years: HR = 1.52, 95% CI = 0.80,2.92). Separate analyses by birth cohort revealed a non-significantly higher incidence in the subgroup born from 1926 to 1934 (HR = 1.30, 95% CI = 0.62,2.76). Delay in menarche among women remaining in Guernsey during the Occupation, rather than being protective, was associated with an increased risk of breast cancer. [source] Factors associated with antidepressant use in depressed and non-depressed community-dwelling elderly: the three-city studyINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 3 2008Agnès Soudry Abstract Objectives The aim of this study was to identify factors associated with antidepressant use in non-depressed and depressed elderly persons, assuming that they varied according to clinical status. Methods We studied 7,868 French community-dwelling subjects aged 65 years and over. The Center for Epidemiological Studies-Depression scale and the Mini International Neuropsychiatric Interview were used to define three groups: non-depressed, high depressive symptoms and current major depressive disorder. Separate analyses were performed to identify the factors which were associated with antidepressant use in each group. Results Antidepressant use (55% selective serotonin re-uptake inhibitors, 25% tricyclic antidepressants, 20% other types) increased from 4.9% in non-depressed subjects to 17.3% in subjects with high depressive symptoms (HDS) and 33.6% of in those with current major depressive disorder (MDD). The factors associated with antidepressant use varied according to depression status. In particular, men with current MDD were more often treated with antidepressants than women whereas, in both the HDS and the non-depressed groups, antidepressant use was, as has been observed elsewhere, more frequent in women. Gender also had a strong modifying effect on the relationship between antidepressant use and history of major depression. Finally, the direction of the association between antidepressant use and cognitive performance varied according to depression status. Conclusions This study showed that the direction and strength of the association between antidepressant use and demographic and health-related factors varied according to the severity of depression symptoms. Further studies are needed to clarify the relationship between gender and cognition and antidepressant use. Copyright © 2007 John Wiley & Sons, Ltd. [source] Patterns in marine hydrozoan richness and biogeography around southern Africa: implications of life cycle strategyJOURNAL OF BIOGEOGRAPHY, Issue 4 2010Mark J. Gibbons Abstract Aim, To examine patterns of marine hydrozoan richness around southern Africa and to test the hypothesis that patterns of biogeography become weaker with increasing dispersal ability. Location, The coastline of southern Africa from 21° S, 14° E to 28° S, 33° E, extending from the intertidal zone seawards a distance of 200 nautical miles. Methods, Published and unpublished information on the distribution of marine Hydrozoa was entered as presence/absence data onto a gridded coastline of the region. A similarity matrix between the species composition of grid squares was constructed using the Bray,Curtis index and visualized using non-metric multidimensional scaling ordinations. Separate analyses were conducted, and compared, on the three major life cycle groupings: holoplanktic, meroplanktic and benthic. Results, Over 450 species of marine Hydrozoa have been reported from the region, and species richness increases eastwards, in a manner at odds with the distribution of sampling effort. There was a significant correlation between the geographic structures of the resemblance matrices generated for the three life cycle groupings. In other words, all three groups showed similar patterns of biogeography around the region, and these were broadly similar to those reported by others. However, there were differences between them that reflect the resolution at which the data were examined. At a level of 40% similarity, there was no biogeographic structure to the holoplanktic fauna, the meroplanktic taxa were simply sub-divided into cool- and warm-temperate/subtropical elements, and in the case of benthic taxa, the cool-water fauna was further split into a southern Namaqua and a depauperate northern Namib component. Even at a resolution of 70% similarity, the holopelagic taxa could be separated only into cool-temperate and warm-temperate/subtropical faunas. Main conclusions, Holoplanktic taxa show comparatively less biogeographic structure than meroplanktic taxa, which in turn show less clearly defined biogeographic structure than benthic taxa. It is suggested that this is related to the interaction between oceanography and dispersive-stage duration. The role that the Agulhas Current plays in influencing the Benguela Current fauna is highlighted. This study has implications for conservation planning exercises based on protecting representative biotopes in different biogeographic regions. [source] Abiotic and biotic drivers of seedling survival in a hurricane-impacted tropical forestJOURNAL OF ECOLOGY, Issue 6 2009Liza S. Comita Summary 1. ,Many forests experience periodic, large-scale disturbances, such as hurricanes and cyclones, which open the forest canopy, causing dramatic changes in understorey light conditions and seedling densities. Thus, in hurricane-impacted forests, large variations in abiotic and biotic conditions likely shape seedling dynamics, which in turn will contribute to patterns of forest recovery. 2. ,We monitored 13 836 seedlings of 82 tree and shrub species over 10 years following Hurricane Georges in 1998 in a subtropical, montane forest in Puerto Rico. We quantified changes in the biotic and abiotic environment of the understorey and linked seedling dynamics to changes in canopy openness and seedling density, and to spatial variation in soil type, topography and tree density. 3. ,Canopy openness was highest when first measured after Hurricane Georges and dropped significantly within c. 3 years, while seedling densities remained high for c. 5 years post-hurricane. When all species and census intervals were analysed together, generalized linear mixed effects models revealed that canopy openness, seedling and adult tree densities were significant drivers of seedling survival. 4. ,The relative importance of abiotic and biotic factors changed over time. Separate analyses for each census interval revealed that canopy openness was a significant predictor of survival only for the first census interval, with lower survival at the highest levels of canopy openness. The effect of conspecific seedling density was significant in all intervals except the first, and soil type only in the final census interval. 5. ,When grouping species into life-history guilds based on adult tree susceptibility to hurricane damage, we found clear differences among guilds in the effects of biotic and abiotic factors on seedling survival. Seedlings of hurricane-susceptible and intermediate guilds were more strongly influenced by canopy openness, while seedlings of the hurricane-resistant group were less affected by conspecific seedling density. Individual species-level analyses for 12 common species, however, showed considerable variation among species within guilds. 6. ,Synthesis. Our results suggest that hurricanes shape species composition by altering understorey conditions that differentially influence the success of seedlings. Thus, predicted increases in the intensity and frequency of hurricanes in the Caribbean will likely alter seedling dynamics and ultimately the species composition in hurricane-impacted forests. [source] Seasonal Variation in Fluoride Intake: the Iowa Fluoride StudyJOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 4 2004Barbara Broffitt MS; ABSTRACT Objectives: Although patterns of fluid intake change seasonally, little is known about how fluoride intake varies by season. Since even short-term increases in fluoride intake could potentially lead to more dental fluorosis, it is valuable to assess the degree of seasonal variation to determine if it increases fluoride intake to levels that could be considered a concern in young children. Methods: Questionnaires were mailed periodically to participants in the Iowa Fluoride Study beginning at 6 weeks of age and continuing for a number of years. Parents recorded the date; child's weight; estimates of the amounts of water and other beverages that their child consumed per week; the type and amount of any fluoride supplements used; and the type, amount, and frequency of dentifrice used, with an estimate of the proportion of dentifrice that was swallowed. Documented water fluoride levels from municipal sources and assay of individual sources were linked to water intake amounts. Total fluoride intake per kg body weight was estimated from water, other beverages, fluoride supplements, and ingested dentifrice. Generalized linear models compared temperature-related and seasonal effects after adjusting for the child's age. Results: Separate analyses for ages 0,12 months and 12,72 months showed different results. Children younger than 12 months of age did not exhibit significant seasonal or temperature-related variation in any of the components of fluoride intake. Children aged 12,72 months had higher fluoride intake (mg F/kg bw) from beverages in summer (P <.05), and fluoride intake from beverages increased with monthly temperature (P <.001). Conclusions: Fluoride intake from beverages for children aged 12,72 months is slightly higher in the summer and increases with mean monthly temperature. Fluoride intake from supplements and dentifrice did not change significantly with either season or temperature. [source] Direct measurement of spatial autocorrelation at the community level in four plant communitiesJOURNAL OF VEGETATION SCIENCE, Issue 6 2000Maia Mistral Abstract. Four sites were sampled to determine spatial autocorrelation in vegetation at the community level. All were in western New Zealand, but on different substrates and of different physiognomy: a terrace forest, a floodplain forest, a mire and the middle of a logging road. In ,dissimograms'the four communities all showed steady increases in dissimilarity with distance, but with shoulders in the curve for some sites, which could be related to plant morphology. Most of the increase in dissimilarity occurred over very short distances: less than 0.5 m in the forests, less than 1 m in the mire and less than 2 m in the road. Separate analyses of the woody and herbaceous guilds in the floodplain forest showed that herbaceous dissimilarities remained low at distances up to 20 m, probably because of clonal structure in some species. The mire showed low overall dissimilarity, which is attributed to the uniform substrate and the small species pool. Simulations showed that the approach is capable of indicating structure when it is present. Although the dissimogram was clearest when analysing a simulated grid of patches, other types of simulated patchiness showed dissimograms that were clearly distinguishable from those obtained from the vegetation studied. The almost continuous rise in dissimilarity with distance found in the four sites offers no support to the Hierarchy theory, fitting much more closely the alternative Continuum theory. [source] Monophyletic groups within ,higher land birds', comparison of morphological and molecular dataJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 4 2003G. Mayr Abstract The relationships within the ,higher land birds' and putatively related taxa are analysed in a study using 89 morphological characters and DNA sequences of three nuclear, protein-coding genes, c- myc, RAG-1, and myoglobin intron II. Separate analyses of the different data sets and a ,total evidence' analysis in which the data sets of the morphological and molecular analyses were combined are compared. All three analyses support the hitherto disputed sister group relationship between Pici (Ramphastidae, Indicatoridae and Picidae) and Galbulae (Galbulidae and Bucconidae). Previously unrecognized osteological synapomorphies of this clade are presented. All analyses further resulted in monophyly of the taxon [Aegothelidae + (Apodidae/Hemiprocnidae + Trochilidae)]. Analysis of the morphological data and of the combined data set also supported monophyly of the taxon [Strigiformes + (Falconidae + Accipitridae)]. The morphological data further support monophyly of the taxon (Upupidae + Bucerotidae). Other placements in the three analyses received either no or only weak bootstrap support. [source] Human leukocyte antigen and adult living-donor liver transplantation outcomes: An analysis of the organ procurement and transplantation network database,LIVER TRANSPLANTATION, Issue 10 2007S. Simona Jakab Human leukocyte antigen (HLA) compatibility has no clinically significant impact in cadaveric liver transplantation. Less is known regarding living-donor liver transplantation (LDLT). Our prior analysis of the Organ Procurement and Transplantation Network (OPTN) database suggested a higher graft failure rate in patients who underwent LDLT from donors with close HLA match. We further investigated the effect of HLA-A, -B, and -DR matching on 5-yr graft survival in adult LDLT by analyzing OPTN data regarding adult LDLT performed between 1998 and 2005. We evaluated associations between 5-yr graft survival and total, locus-specific, and haplotype match levels. Separate analyses were conducted for recipients with autoimmune (fulminant autoimmune hepatitis, cirrhosis secondary to autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis) or nonautoimmune liver disease. Multivariable Cox proportional hazard models were used to evaluate interactions and adjust for potential confounders. Among 631 patients with available donor/recipient HLA data, the degree of HLA match had no significant effect on 5-yr graft survival, even when analyzed separately in recipients with autoimmune vs. nonautoimmune liver disease. To be able to include all 1,838 adult LDLTs, we considered a first-degree related donor as substitute for a close HLA match. We found no difference in graft survival in related vs. unrelated pairs. In conclusion, our results show no detrimental impact of close HLA matching on graft survival in adult LDLT, including in recipients with underlying autoimmune liver disease. Liver Transpl 13:1405,1413, 2007. © 2007 AASLD. [source] The Stability of General Foreign Language Classroom Anxiety across English and FrenchMODERN LANGUAGE JOURNAL, Issue 3 2003M´ximo Rodríguez The present study examined the stability of the general foreign language classroom anxiety construct across English and French. Preservice teachers from two western universities in Venezuela, who were majoring simultaneously in these two foreign languages, participated in the study. The students represented a variety of levels within each language. They completed two Spanish versions (one for each language) of the Foreign Language Classroom Anxiety Scale (FLCAS; Horwitz, Horwitz, & Cope, 1986). Separate analyses were performed on the full sample and on a restricted sample that included only those students who were at the same level in both languages. The results supported the indirect findings reported by Saito, Horwitz, and Garza (1999) while providing direct evidence suggesting the stability of the construct across English and French. Evidence obtained for overall, within-institution, and within-level comparisons. Furthermore, analysis of psychometric technical aspects of the FLCAS indicated that the scale exhibited high reliability but moderate construct validity. [source] Prevalence of risk factors for suicide in patients prescribed venlafaxine, fluoxetine, and citalopram,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 6 2005Daniel Mines MD Abstract Purpose Three recent observational studies reported that the risk of fatal overdose is greater with venlafaxine than SSRI use. It is not clear whether patient factors could account for this finding. We evaluated whether risk factors for suicide are more prevalent among patients prescribed venlafaxine than patients prescribed fluoxetine or citalopram. Methods Using data from the UK General Practice Research Database (GPRD), we identified patients who were first prescribed any of the three drugs between January 1995 and April 2002. We ascertained risk factors for suicide documented in the 1 year before that first prescription. Separate analyses compared venlafaxine (N,=,27,096) and fluoxetine (N,=,134,996) cohorts, and venlafaxine and citalopram (N,=,52,035) cohorts. Results Previous suicidal behaviors were documented for 1.0% of the venlafaxine cohort compared to 0.4% of the fluoxetine cohort (OR 2.8, 95%CI: 2.4, 3.2) and 0.4% citalopram cohorts (OR 2.4, 95%CI: 2.0, 2.9). 72.5% of venlafaxine patients had been prescribed at least one other antidepressant compared to 27.6% of fluoxetine (OR 6.9, 95%CI: 6.7, 7.1) and 39.5% of citalopram (OR 4.0, 95%CI: 3.9, 4.2) patients. Venlafaxine patients were also four to six times as likely to have been previously hospitalized for depression. Conclusion In the UK, venlafaxine has been selectively prescribed to a patient population with a higher burden of suicide risk factors than patients prescribed fluoxetine and citalopram. Unless baseline population differences are accounted for, observational studies that compare the risk of suicide in patients receiving these agents may produce biased results. Copyright © 2005 John Wiley & Sons, Ltd. [source] Sex Differentials in Childhood Feeding, Health Care, and Nutritional Status in IndiaPOPULATION AND DEVELOPMENT REVIEW, Issue 2 2004Vinod Mishra Strong preference for sons in South Asia is well documented, but evidence on female disadvantage in childhood feeding, health care, and nutritional status is inconclusive. This article examines sex differentials in indicators of childhood feeding, health care, and nutritional status of children under age 3 by birth order and sex composition of older living siblings. Data are from India's 1992,93 and 1998,99 National Family Health Surveys. The analysis finds three reasons for inconclusive evidence on female disadvantage in aggregate analyses. First, discrimination against girls is limited to the relatively small fraction of children of certain birth orders and sex compositions of older siblings. Second, discrimination against girls when boys are in short supply and discrimination against boys when girls are in short supply cancel each other to some extent. Third, some discrimination against girls (e.g., in exclusive breastfeeding at 6,9 months) is nutritionally beneficial to girls. Separate analyses for North and South India find that gender discrimination is as common in the South as in the North, where son preference is generally much stronger. [source] Risk and Promotive Factors Related to Depressive Symptoms Among Japanese YouthAMERICAN JOURNAL OF ORTHOPSYCHIATRY, Issue 4 2007Julie Laser Symptoms of depression include feelings of sadness, loneliness, suicidal ideation, and self-dislike. Adolescent depression is viewed as a problem in Japan, but there is little research on the correlates of depression in Japanese youth. Therefore, the purpose of this study was to investigate the prevalence of depression in Japanese youth and to examine correlates of depression using a risk and promotive factor framework. This study examined the symptoms of depression among 802 Japanese youth attending postsecondary schools in the Sapporo area. Separate analyses were conducted for males and females to determine whether the importance of risk and promotive factors varied by gender. The results showed that many factors that had been linked to depressive symptoms in Western samples were predictive of depressive symptoms in Japanese youth. The risk and promotive factors accounted for 50% and 59% of the variance in depressive symptoms for the female and male subsamples, respectively. [source] The effect of implementation intentions on prospective memory performance across the lifespanAPPLIED COGNITIVE PSYCHOLOGY, Issue 5 2010Thomas D. Zimmermann Differences in the amount and availability of cognitive resources may be responsible for age-related differences in event-based prospective memory tasks. We hypothesised that a manipulation which reduces resource requirements by enhancing automatic processing will reduce age differences. Implementation intentions are assumed to satisfy this requirement. We tested a total of 563 participants, 185 adolescents, 193 young adults and 185 older adults in order to investigate whether providing participants with implementation intention instructions would improve performance, whether any improvement would vary with age, and whether it would affect the prospective component or the retrospective component. The results showed a benefit of implementation intentions for older adults, but not for adolescents and for young adults. Separate analyses for the prospective and the retrospective components revealed that this effect was based mainly on a performance facilitation of the prospective component. These results suggest that implementation intentions provide a means to reduce age differences in prospective memory. Copyright © 2009 John Wiley & Sons, Ltd. [source] The protective effect of antimalarial drugs on thrombovascular events in systemic lupus erythematosusARTHRITIS & RHEUMATISM, Issue 3 2010Hyejung Jung Objective The antimalarial medication hydroxychloroquine has been proposed as a thromboprotective agent in systemic lupus erythematosus (SLE), but studies thus far have been limited by the possibility of confounding by indication. This study was conducted to assess whether exposure to antimalarial drugs is associated with a decrease in thrombovascular events (TEs) in patients with SLE. Methods The study was designed as a nested case,control study embedded in an inception cohort of patients with SLE, which allowed adjustments for possible confounding by calendar year, duration of disease, duration of observation, and severity of lupus. After controlling for the possible confounding variables in conditional logistic regression models, the use of antimalarial drugs was assessed for its effects on the development of TEs in lupus patients. Results Fifty-four cases of TE were identified, and these were matched with 108 control subjects (lupus patients without TEs). Univariate analyses identified older age (odds ratio [OR] 1.04, 95% confidence interval [95%CI] 1.01,1.07) or being older than age 50 years (OR 3.5, 95% CI 1.4,8.6) and ever having hypertension (OR 2.5, 95% CI 1.0,5.8) as being associated with an increased risk of TEs, whereas use of antimalarial drugs (OR 0.31, 95% CI 0.13,0.71) was associated with a decreased risk of TEs. Separate analyses were done for arterial and venous TEs, which yielded similar results. In multivariate analyses, use of antimalarial drugs (OR 0.32, 95% CI 0.14,0.74) and older age (OR 1.04, 95% CI 1.01,1.07) were the only 2 variables that remained significant. Conclusion The results from this nested case,control study demonstrate that, after accounting for the effects of disease severity, disease duration, and calendar year, antimalarial drugs were found to be thromboprotective, being associated with a 68% reduction in the risk of all TEs, with a range of risk reduction of at least 26% up to as high as 86%. [source] Sources of character conflict in a clade of water striders (Heteroptera: Gerridae)CLADISTICS, Issue 6 2003Jakob Damgaard Incongruence among trees reconstructed with different data may stem from historical (gene tree-species tree conflict) or process (character change biases) phenomena. Regardless of the source, incongruent data, as determined with "global" measures of homoplasy, have often been excluded from parsimony analysis of the combined data. Recent studies suggest that these homoplasy measures do not predict the contribution of each character to overall tree structure. Branch support measures identify, on a character to node basis, sources of support and conflict resulting from a simultaneous analysis of the data. We implement these branch support measures to identify sources of character conflict in a clade of water striders consisting of Gerris Fabricius, Aquarius Schellenberg, and Limnoporus Stål species. Separate analyses of morphology, mitochondrial cytochrome oxidase I (COI), large mitochondrial ribosomal subunit (16SrRNA), and elongation factor-1, (EF-1,) data resulted in cladograms that varied in resolution and topological concordance. Simultaneous analysis of the data resulted in two trees that were unresolved for one node in a strict consensus. The topology agreed with current classification except for the placements of Aquarius chilensis and the Aquarius remigis species group closer to Gerris than to congeneric species. Branch support measures indicated that support derived from each data set varied among nodes, but COI had an overall negative effect on branch support. However, Spearman rank correlation of partitioned branch support values indicated no negative associations of branch support between any data sets and a positive association between EF-1, and 16SrRNA. Thus incongruence among data sets was not drastic and the gene-tree versus species tree phenomenon was not implicated. Biases in character change were a more likely reason for incongruence, although saturation curves and incongruence length difference for COI indicated little potential for homoplasy. However, a posteriori inspection of COI nucleotide change with reference to the simultaneous analysis tree revealed AT and codon biases. These biases were not associated with branch support measures. Therefore, it is difficult to predict incongruence or identify its cause. Exclusion of data is ill advised because every character is potentially parsimony informative. [source] Rural nonfarm activities and agricultural crop production in NigeriaAGRICULTURAL ECONOMICS, Issue 2 2009Gbemisola Oseni Nigeria; Rural nonfarm activities; Agricultural crop expenditures; Credit constraints Abstract Although most rural households are involved in the farm sector, the nonfarm sector has grown significantly in recent decades, and its role in rural development has become increasingly important. This article examines the effect of participation in nonfarm activities on crop expenses of farm households in Nigeria. The relationship is modeled using a nonseparable agricultural household model that suggests that participating in nonfarm activities can relax the credit constraints facing farm households and reduce risk thereby helping households improve farm production and smooth consumption over time. The results show that participation in nonfarm activities by Nigerian farmers has a positive and significant effect on crop expenses and in particular on payments for hired labor and inorganic fertilizers. Separate analysis of the six geopolitical zones in Nigeria indicates that it is in the South-South and South-East zones where nonfarm participation appears to induce more hiring of labor. The results support the hypothesis that nonfarm participation helps relax liquidity constraints but suggests how that liquidity is used is zone-specific. In general, the results also indicate that liquidity is used more to pay for inputs into staple production as opposed to cash crops. [source] Economic Relationship Between Alcohol and Cannabis RevisitedTHE ECONOMIC RECORD, Issue 248 2004Jenny Williams Consuming cannabis in combination with alcohol is common among Australian cannabis users. This paper investigates whether the economic relationship between cannabis and alcohol is affected by the manner in which these two substances are used. Our results indicate that cannabis and alcohol are economic complements for all cannabis users, but this relationship is stronger for cannabis users who tend to use alcohol and cannabis together, whom we refer to as polysubstance users. Separate analysis by gender suggests that cannabis consumption by polysubstance and non-polysubstance using males is more responsive to changes in the full price of alcohol than their female counterparts. [source] Kinetics of both synchronous and asynchronous quantal release during trains of action potential-evoked EPSCs at the rat calyx of HeldTHE JOURNAL OF PHYSIOLOGY, Issue 2 2007V. Scheuss We studied the kinetics of transmitter release during trains of action potential (AP)-evoked excitatory postsynaptic currents (EPSCs) at the calyx of Held synapse of juvenile rats. Using a new quantitative method based on a combination of ensemble fluctuation analysis and deconvolution, we were able to analyse mean quantal size (q) and release rate (,) continuously in a time-resolved manner. Estimates derived this way agreed well with values of q and quantal content (M) calculated for each EPSC within the train from ensemble means of peak amplitudes and their variances. Separate analysis of synchronous and asynchronous quantal release during long stimulus trains (200 ms, 100 Hz) revealed that the latter component was highly variable among different synapses but it was unequivocally identified in 18 out of 37 synapses analysed. Peak rates of asynchronous release ranged from 0.2 to 15.2 vesicles ms,1 (ves ms,1) with a mean of 2.3 ± 0.6 ves ms,1. On average, asynchronous release accounted for less than 14% of the total number of about 3670 ± 350 vesicles released during 200 ms trains. Following such trains, asynchronous release decayed with several time constants, the fastest one being in the order of 15 ms. The short duration of asynchronous release at the calyx of Held synapse may aid in generating brief postsynaptic depolarizations, avoiding temporal summation and preserving action potential timing during high frequency bursts. [source] Getting better byte by byte: a pilot randomised controlled trial of email therapy for bulimia nervosa and binge eating disorder,EUROPEAN EATING DISORDERS REVIEW, Issue 2 2008Paul Robinson Abstract One hundred and ten people in an university population responded to emailed eating disorder questionnaires. Ninty-seven fulfilling criteria for eating disorders (bulimia nervosa (BN), binge eating disorder (BED), EDNOS) were randomised to therapist administered email bulimia therapy (eBT), unsupported Self directed writing (SDW) or Waiting list control (WLC). Measures were repeated at 3 months. Diagnosis, Beck depression inventory (BDI) and Bulimia investigatory test (BITE) scores were recorded. Follow-up rate was 63% and results must be interpreted cautiously. However significantly fewer participants who had received eBT or SDW fulfilled criteria for eating disorders at follow up compared to WLC. There was no significant difference between eBT and SDW in the analysis of variance (ANOVA), although in separate analyses, eBT was significantly superior to WLC (p,<,0.02) and the difference for SDW approached significance (p,=,0.06). BDI and BITE scores showed no significant change. For eBT participants there was a significant positive correlation between words written and improvement in BITE severity score. BN, BED and EDNOS can be treated via email. Copyright © 2007 John Wiley & Sons, Ltd and Eating Disorders Association. [source] Meta-analysis of standardized incidence and mortality rates of childhood leukaemia in proximity to nuclear facilitiesEUROPEAN JOURNAL OF CANCER CARE, Issue 4 2007P.J. BAKER phd The meta-analysis combined and statistically analysed studies of childhood leukaemia and nuclear facilities. Focus was on studies that calculated standardized rates for individual facilities. Due to variability between study designs, eight separate analyses were performed stratified by age and zone. One hundred and thirty-six sites were used in at least one analysis. Unadjusted, fixed effects and random effects models were used. Meta-rates greater than one were found in all models at all stratification levels often achieving statistical significance. Caution must be used when interpreting these results. The meta-analysis was able to show an increase in childhood leukaemia near nuclear facilities, but does not support a hypothesis to explain the excess. Each type of model utilized has limitations. Fixed effects models give greater weight to larger studies; however, population density may be a risk factor. Random effects models give greater weight to smaller studies that may be more likely to be affected by publication bias. A limitation of the overall study design is that standardized rates must be available for individual sites which led to exclusion of studies that only calculated rates for multiple sites and those that presented other statistical methods. Further, dose-response studies do not support excess rates found near nuclear facilities. However, it cannot be ignored that the majority of studies have found elevated rates, although not usually statistically significant. [source] Are stock assessment methods too complicated?FISH AND FISHERIES, Issue 3 2004A J R Cotter Abstract This critical review argues that several methods for the estimation and prediction of numbers-at-age, fishing mortality coefficients F, and recruitment for a stock of fish are too hard to explain to customers (the fishing industry, managers, etc.) and do not pay enough attention to weaknesses in the supporting data, assumptions and theory. The review is linked to North Sea demersal stocks. First, weaknesses in the various types of data used in North Sea assessments are summarized, i.e. total landings, discards, commercial and research vessel abundance indices, age-length keys and natural mortality (M). A list of features that an ideal assessment should have is put forward as a basis for comparing different methods. The importance of independence and weighting when combining different types of data in an assessment is stressed. Assessment methods considered are Virtual Population Analysis, ad hoc tuning, extended survivors analysis (XSA), year-class curves, catch-at-age modelling, and state-space models fitted by Kalman filter or Bayesian methods. Year-class curves (not to be confused with ,catch-curves') are the favoured method because of their applicability to data sets separately, their visual appeal, simple statistical basis, minimal assumptions, the availability of confidence limits, and the ease with which estimates can be combined from different data sets after separate analyses. They do not estimate absolute stock numbers or F but neither do other methods unless M is accurately known, as is seldom true. [source] Global analysis of reptile elevational diversityGLOBAL ECOLOGY, Issue 4 2010Christy M. McCain ABSTRACT Aim, Latitudinal- and regional-scale studies of reptile diversity suggest a predominant temperature effect, unlike many other vertebrate richness patterns which tend to be highly correlated with both temperature and water variables. Here I examine montane gradients in reptile species richness with separate analyses of snakes and lizards from mountains around the world to assess a predominant temperature effect and three additional theories of diversity, including a temperature,water effect, the species,area effect and the mid-domain effect (MDE). Location, Twenty-five elevational gradients of reptile diversity from temperate, tropical and desert mountains in both hemispheres, spanning 10.3° N to 46.1° N. Methods, Elevational gradients in reptile diversity are based on data from the literature. Of the 63 data sets found or compiled, only those with a high, unbiased sampling effort were used in analyses. Twelve predictions and three interactions of diversity theory were tested using nonparametric statistics, linear regressions and multiple regression with the Akaike information criterion (AIC). Results, Reptile richness and, individually, snake and lizard richness on mountains followed four distinct patterns: decreasing, low-elevation plateaus, low-elevation plateaus with mid-elevation peaks, and mid-elevation peaks. Elevational reptile richness was most strongly correlated with temperature. The temperature effect was mediated by precipitation; reptile richness was more strongly tied to temperature on wet gradients than on arid gradients. Area was a secondary factor of importance, whereas the MDE was not strongly associated with reptile diversity on mountains. Main conclusions, Reptile diversity patterns on mountains did not follow the predicted temperature,water effect, as all diversity patterns were found on both wet and dry mountains. But the influence of precipitation on the temperature effect most likely reflects reptiles' use of radiant heat sources (sunning opportunities) that are more widespread on arid mountains than wet mountains due to lower humidity, sparser vegetation and less cloud cover across low and intermediate elevations. [source] Factors Associated with the Income Distribution of Full-Time Physicians: A Quantile Regression ApproachHEALTH SERVICES RESEARCH, Issue 5 2007Ya-Chen Tina Shih Objective. Physician income is generally high, but quite variable; hence, physicians have divergent perspectives regarding health policy initiatives and market reforms that could affect their incomes. We investigated factors underlying the distribution of income within the physician population. Data Sources. Full-time physicians (N=10,777) from the restricted version of the 1996,1997 Community Tracking Study Physician Survey (CTS-PS), 1996 Area Resource File, and 1996 health maintenance organization penetration data. Study Design. We conducted separate analyses for primary care physicians (PCPs) and specialists. We employed least square and quantile regression models to examine factors associated with physician incomes at the mean and at various points of the income distribution, respectively. We accounted for the complex survey design for the CTS-PS data using appropriate weighted procedures and explored endogeneity using an instrumental variables method. Principal Findings. We detected widespread and subtle effects of many variables on physician incomes at different points (10th, 25th, 75th, and 90th percentiles) in the distribution that were undetected when employing regression estimations focusing on only the means or medians. Our findings show that the effects of managed care penetration are demonstrable at the mean of specialist incomes, but are more pronounced at higher levels. Conversely, a gender gap in earnings occurs at all levels of income of both PCPs and specialists, but is more pronounced at lower income levels. Conclusions. The quantile regression technique offers an analytical tool to evaluate policy effects beyond the means. A longitudinal application of this approach may enable health policy makers to identify winners and losers among segments of the physician workforce and assess how market dynamics and health policy initiatives affect the overall physician income distribution over various time intervals. [source] Caffeine, cognitive failures and health in a non-working community sampleHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 1 2009Andrew P Smith Abstract Rationale Most studies of the effects of caffeine on performance have been conducted in the laboratory and further information is required on the real-life effects of caffeine consumption on cognition. In addition, possible effects of caffeine consumption on a range of health outcomes should also be assessed in these studies to enable cost-benefit analyses to be conducted. Objectives Secondary analyses of a large epidemiological database (N,=,3223 non-working participants, 57% female, with a mean age of 49.6 years, range 17,92 years) were conducted to examine associations between caffeine consumption (mean caffeine consumption was 140,mg/day, range 0,1800,mg) and cognitive failures (errors of memory, attention and action) in a non-working sample. Associations between caffeine consumption and physical and mental health problems were also examined. Methods The study involved secondary analyses of a database formed by combining the Bristol Stress and Health at Work and Cardiff Health and Safety at Work studies. Associations between caffeine consumption and frequency of cognitive failures and health outcomes were examined in a sample of non-workers. Results After controlling for possible confounding factors significant associations between caffeine consumption and fewer cognitive failures were observed. Initial analyses suggested that many health variables were associated with regular level of caffeine consumption. However, most of the significant effects of caffeine disappeared when demographic and lifestyle factors were controlled for. Consumption of caffeine was, however, associated with a reduced risk of depression. These effects were also observed in separate analyses examining the source of the caffeine (coffee and tea). Conclusions Overall, the results show that caffeine consumption may benefit cognitive functioning in a non-working population. This confirms earlier findings from working samples. This beneficial effect of caffeine was not associated with negative health consequences. Indeed, consumption of caffeine was found to be associated with a reduced risk of depression. Copyright © 2008 John Wiley & Sons, Ltd. [source] Circulating enterolactone and prostate cancer risk: A Nordic nested case-control studyINTERNATIONAL JOURNAL OF CANCER, Issue 1 2002Pär Stattin Abstract Enterolactone, a phytoestrogen belonging to the class of lignans, is produced by the intestinal microflora from precursors in plant foods and has been implicated in protection against cancer. We study the effect of enterolactone on the risk of a subsequent diagnosis of prostate cancer. We conducted a longitudinal, nested case-control study by linkage of 3 biobanks to the cancer registries in Finland, Norway and Sweden, respectively. Enterolactone concentrations were measured by time-resolved fluoroimmunoassay in serum from 794 men who had a diagnosis of prostate cancer at a mean follow-up time of 14.2 years after blood collection and among 2,550 control men matched within each cohort for age (±2 years), date of blood collection (±2 months) and county. The median enterolactone concentrations did not differ between case and control subjects in the full study group (8.4 nmol/L [25th,75th percentile = 4.5,15.0] vs. 8.5 nmol/L [25th,75th percentile = 4.3,15.9]), nor in the national groups. Odds ratios of prostate cancer risk estimated by conditional logistic regression for increasing concentrations of enterolactone in quartiles in the full study group were 1.00 (referent), 1.21 (95% confidence interval [CI] = 0.96,1.52), 1.16 (95% CI = 0.91,1.47) and 1.08 (95% CI = 0.83,1.39). The OR estimate for the highest vs. the lowest quartile of enterolactone in separate analyses of the Norwegian, Finnish and Swedish cohort was 1.21 (95% CI = 0.91,1.60), 1.02 (95% CI = 0.59,1.76) and 0.87 (95% CI = 0.45,1.67), respectively. No support for the hypothesis that high circulating enterolactone is protective against prostate cancer was found. © 2002 Wiley-Liss, Inc. [source] Are Aggressive Treatment Strategies Less Cost-Effective for Older Patients?JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 4 2001Aggressive Care for Patients with Acute Respiratory Failure, The Case of Ventilator Support OBJECTIVES: A common assumption is that life-sustaining treatments are much less cost-effective for older patients than for younger patients. We estimated the incremental cost-effectiveness of providing mechanical ventilation and intensive care for patients of various ages who had acute respiratory failure. DESIGN: Retrospective analysis of data on acute respiratory failure from Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT). SETTING: Acute hospital. PARTICIPANTS: 1,005 with acute respiratory failure; 963 received ventilator support and 42 had ventilator support withheld. MEASUREMENTS: We studied 1,005 patients enrolled in a five-center study of seriously ill patients (SUPPORT) with acute respiratory failure (pneumonia or acute respiratory distress syndrome and an Acute Physiology Score ,10) requiring ventilator support. For cost-effectiveness analyses, we estimated life expectancy based on long-term follow-up of SUPPORT patients and estimated utilities (quality-of-life weights) using time-tradeoff questions. We used hospital fiscal data and Medicare data to estimate healthcare costs. We divided patients into three age groups (<65, 65,74, and ,75 years); for each age group, we performed separate analyses for patients with a ,50% probability of surviving at least 2 months (high-risk group) and those with a> 50% probability of surviving at least 2 months (low-risk group). RESULTS: Of the 963 patients who received ventilator support, 44% were female; 48% survived 6 months; and the median (25th, 75th percentile) age was 63 (46, 75) years. For the 42 patients for whom ventilator support was withheld, the median survival was 3 days. For low-risk patients (>50% estimated 2-month survival), the incremental cost (1998 dollars) per quality-adjusted life-year (QALY) saved by providing ventilator support and aggressive care increased across the three age groups ($32,000 for patients age <65, $44,000 for those age 65,74, and $46,000 for those age ,75). For high-risk patients, the incremental cost-effectiveness was much less favorable and was least favorable for younger patients ($130,000 for patients age <65, $100,000 for those age 65,74, and $96,000 for those age ,75). When we varied our assumptions from 50% to 200% of our baseline estimates in sensitivity analyses, results were most sensitive to the costs of the index hospitalization. CONCLUSIONS: For patients with relatively good short-term prognoses, we found that ventilator support and aggressive care were economically worthwhile, even for patients 75 years and older. For patients with poor short-term prognoses, ventilator support and aggressive care were much less cost-effective for adults of all ages. [source] Estimation of immigration rate using integrated population modelsJOURNAL OF APPLIED ECOLOGY, Issue 2 2010Fitsum Abadi Summary 1.,The dynamics of many populations is strongly affected by immigrants. However, estimating and modelling immigration is a real challenge. In the past, several methods have been developed to estimate immigration rate but they either require strong assumptions or combine in a piecewise manner the results from separate analyses. In most methods the effects of covariates cannot be modelled formally. 2.,We developed a Bayesian integrated population model which combines capture,recapture data, population counts and information on reproductive success into a single model that estimates and models immigration rate, while directly assessing the impact of environmental covariates. 3.,We assessed parameter identifiability by comparing posterior distributions of immigration rates under varying priors, and illustrated the application of the model with long term demographic data of a little owl Athene noctua population from Southern Germany. We further assessed the impact of environmental covariates on immigration. 4.,The resulting posterior distributions were insensitive to different prior distributions and dominated by the observed data, indicating that the immigration rate was identifiable. Average yearly immigration into the little owl population was 0·293 (95% credible interval 0·183,0·418), which means that ca 0·3 female per resident female entered the population every year. Immigration rate tended to increase with increasing abundance of voles, the main prey of little owls. 5.Synthesis and applications. The means to estimate and model immigration is an important step towards a better understanding of the dynamics of geographically open populations. The demographic estimates obtained from the developed integrated population model facilitate population diagnoses and can be used to assess population viability. The structural flexibility of the model should constitute a useful tool for wildlife managers and conservation ecologists. [source] | |||||||||||||||||||||||||||||||||||||||||||