Spearman's Partial Rank Correlation Research Articles

Pregnancy-induced changes in serum concentrations of perfluoroalkyl substances and the influence of kidney function

BackgroundEpidemiological associations between maternal concentrations of perfluoroalkyl substances (PFAS) and birth weight are inconsistent. There is concern that studies based on samples collected in late pregnancy may be confounded by kidney function but studies of the relation between pregnancy-induced changes in PFAS and kidney function are lacking. Our aims were to investigate changes in serum concentrations of perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) from early to late pregnancy and to explore relations to changes in glomerular filtration rate (GFR) and glomerular pore size.MethodsWe conducted the study in a cohort of 73 pregnancies of normal-weight Swedish women without gestational diabetes and preeclampsia, enrolled 2009–2014. Blood was collected in median weeks 11 and 36, respectively, and analysed PFAS using liquid chromatography-tandem-mass-spectrometry. We estimated GFR based on creatinine and cystatin C and used the ratio eGFRcystatin C/eGFRcreatinine to indicate glomerular pore size. We used Wilcoxon signed-rank test to compare early and late measures and partial Spearman rank correlations to explore relations between changes in PFAS and kidney function.ResultsMedian concentrations of PFNA, PFOA and PFOS decreased by 15–21% but changes were uncorrelated to changes in kidney function (partial R = − 0.06–0.11). The observed increase in median PFHxS concentration of 69% was likely an artefact of systematic measurement error caused by coeluting endogenous inferences.ConclusionsSerum concentrations of PFNA, PFOA and PFOS decrease during pregnancy but the magnitudes of change are unrelated to parallel changes in eGFR and glomerular pore size, suggesting that changes in these indicators of kidney function are not important confounders in studies of PFAS and birth weight in pregnancies without gestational diabetes and preeclampsia.

The Impact of Global Transcriptional Regulation on Bacterial Gene Order.

SummaryBacterial gene expression depends on the allocation of limited transcriptional resources provided a particular growth rate and growth condition. Early studies in a few genes suggested this global regulation to generate a unifying hyperbolic expression pattern. Here, we developed a large-scale method that generalizes these experiments to quantify the response to growth of over 700 genes that a priori do not exhibit any specific control. We distinguish a core subset following a promoter-specific hyperbolic response. Within this group, we sort genes with regard to their responsiveness to the global regulatory program to show that those with a particularly sensitive linear response are located near the origin of replication. We then find evidence that this genomic architecture is biologically significant by examining position conservation of E. coli genes in 100 bacteria. The response to the transcriptional resources of the cell results in an additional feature contributing to bacterial genome organization.

Independent prognostic implications of RRM2 in lung adenocarcinoma.

Background: Ribonucleoside-diphosphate reductase subunit M2 (RRM2) is the catalytic subunit of ribonucleotide reductase and modulates the enzymatic activity, which is essential for DNA replication and repair. However, the role of RRM2 in lung adenocarcinoma (LUAD) remains unclear.Methods: In this study, we explored the expression pattern and prognostic value of RRM2 in LUAD across TCGA, GEO, Oncomine, UALCAN, PrognoScan, and Kaplan-Meier Plotter, and confirmed its independent prognostic value via Cox analyses. LinkedOmics and GEPIA2 were applied to investigate co-expression and functional networks associated with RRM2. Besides, we used TIMER to assess the correlation between RRM2 and the main six types of tumor-infiltrating immune cells. Lastly, the correlations between immune signatures of immunomodulators, chemokines, and 28 tumor-infiltrating lymphocytes (TILs) and RRM2 were examined by tumor purity-corrected partial Spearman's rank correlation coefficient through TIMER portal.Results: RRM2 was found upregulated in tumor tissues in TCGA-LUAD, and validated in multiple independent cohorts. Moreover, whether in TCGA or other cohorts, high RRM2 expression was found to be associated with poor survival. Cox analyses showed that high RRM2 expression was an independent risk factor for overall survival, disease-specific survival, and progression-free survival of LUAD. Functional network analysis suggested that RRM2 regulates RNA transport, oocyte meiosis, spliceosome, ribosome biogenesis in eukaryotes, and cellular senescence signaling through pathways involving multiple cancer-related kinases and E2F family. Also, RRM2 expression correlated with infiltrating levels of B cells, CD4+ T cells, and neutrophils. Subsequent analysis found that B cells and dendritic cells could predict the outcome of LUAD. B cells were identified as an independent risk factor among six types of immune cells through Cox analyses. At last, the correlation analysis showed RRM2 correlated with 67.68% (624/922) of the immune signatures we performed.Conclusion: Our research showed that RRM2 could independently predict the prognosis of LUAD and was associated with immune infiltration. In particular, the tight relationship between RRM2 and B cell marker genes are the potential epicenter of the immune response and one of the critical factors affecting the prognosis. Our findings laid the foundation for further research on the immunomodulatory role of RRM2 in LUAD.

Behavioral inhibition/approach systems constitute risk/protective pathways from ADHD symptoms to depression and anxiety in undergraduate students

Despite the strong positive association between attention-deficit/hyperactivity disorder (ADHD) and depression or anxiety, little is known about the underlying mechanism that links ADHD symptoms to internalizing problems. We aimed to examine the contribution of behavioral inhibition/approach systems (BIS/BAS) in explaining ADHD symptoms, depression, anxiety, and their relationships. A sample of Japanese non-clinical undergraduate students (N = 419) completed the BIS/BAS Scales, Adult ADHD Self-Report Scale, Patient Health Questionnaire-9, and the Generalized Anxiety Disorder-7 Scale. Spearman's partial rank correlation coefficients were calculated to describe the direct association between each of the measured variables. Mann-Whitney's U tests were conducted to compare ADHD symptoms and internalizing problems according to BIS and BAS activation. The results indicated that, although the simple correlation between inattention and anxiety was positive, it turned negative when the BIS was controlled for. Hyperactivity/impulsivity showed a simple positive correlation with all three BAS components: reward responsiveness (RR), drive, and fun seeking (FS). The RR showed negative partial correlation with anxiety. Furthermore, Mann-Whitney's U tests in the high-BIS group indicated that the high-BAS RR group exhibited less depressive symptoms compared with the low-BAS RR group. Further research focusing on interaction of environmental-social factors and neuro-biological factors are required.

Nestedness of waterbird assemblages in the subsidence wetlands recently created by underground coal mining.

Nestedness has been a research focus in fields of island biogeography and community ecology in recent decades. Although nestedness of faunal assemblages has been investigated in natural wetlands, it remains largely unknown whether and why waterbird communities in artificial wetlands follow nested patterns. We examined the existence of nestedness and underlying drivers in waterbird communities in subsidence wetlands that are recently created by large-scale underground coal mining in the North China Plain. Twelve point-count surveys for waterbirds were undertaken approximately every 2 weeks in 55 subsidence wetlands from September 2016 to April 2017. We used the metric WNODF to estimate nestedness of the assemblages. Partial Spearman rank correlations were performed to examine the association between the nestedness and habitat variables (wetland area, landscape connectivity, wetland age, and habitat diversity) as well as life-history traits (body size, clutch size, dispersal ratio, geographical range size, and migrant status) related to species extinction risk and colonization rate. Waterbird assemblages in the subsidence wetlands were significantly nested. After controlling for other independent variables, the magnitude of nestedness was significantly and negatively correlated with wetland area and species trait linked to extinction risk (i.e., geographical range size). Our results indicate that selective extinction may be the main driver of the nestedness of waterbird assemblages in our study system. However, the nestedness was not due to passive sampling, selective colonization, or habitat diversity. From a conservation viewpoint, both large wetlands and waterbirds with a small geographic range should be protected to maximize the preserved species richness.

Comprehensive study on AOD trends over the Indian subcontinent: a statistical approach

ABSTRACTAerosol optical depth (AOD) trend analysis has been carried out using various statistical techniques over Indian sub-regions. AOD data acquired from Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra and Aqua satellites from January 2003 to December 2015 have been utilized in the present study. Mann–Kendall test, Spearman partial rank correlation (SPRC) test, Pearson test, t-test, linear regression analysis, and Sen’s slope estimate are performed on 13 years of AOD data to observe the trend over different Indian sub-regions. AOD trend is found to be positive (0.0035–0.0154 per year) over different Indian sub-regions indicating the enhanced level of suspended particles over the Indian subcontinent. All six methods are evaluated for trend detection using both satellite data. Linear regression and Sen’s slope test provide good estimate of slope values to observe the magnitude of AOD change per year. Mann–Kendall test, SPRC test, and Pearson test support the trends results obtained from linear regression and Sen’s slope estimate. So, these tests are preferable for the trend analyses.

Magnetic resonance imaging based correlation analysis between calcarine sulcus development and isolated fetal ventriculomegaly.

Fetal ventriculomegaly development leads to neurological, motor, and/or cognitive impairment, and is presently diagnosed based on the width of the atrium in the lateral ventricle. But in this study, we have tried to assess the relationship between the development of calcarine sulcus and width of fetal lateral ventricles, to assess if calcarine sulcus can also be used for fetal ventriculomegaly diagnosis. We conducted a retrospective analysis of the magnetic resonance imaging (MRI) data from 45 subjects with isolated mild fetal ventriculomegaly (IMVM). The calcarine sulcus development was divided into three categories based on the depth; Grade 1 (undeveloped), Grade 2 (underdeveloped), and Grade 3 (fully developed), and its correlation with fetal ventriculomegaly was analyzed based on Spearman's partial rank correlation test. Based on this analysis, the width of left and right lateral ventricles showed significant downward trend with the calcarine sulcus maturation [undeveloped (Left 13.88±2.70mm, Right 14.27±3.13mm)→underdeveloped (Left 12.95±1.93mm, Right 11.93±2.24mm)→fully developed (Left 11.06±2.10mm, Right 10.42±2.10mm)] (FLeft =5.12, P=0.01; FRight =10.72, P=1.73×10-4 ). In addition, significant correlations were also observed between the width of the lateral ventricles and the maturity of the calcarine sulcus (Spearman's rank correlation coefficient; -0.47 for the left lateral ventricles and -0.56 for the right, both P<0.001). Overall, our data indicated a negative correlation between the fetal morphological development of calcarine sulcus and the width of lateral ventricles in subjects having isolated fetal ventriculomegaly.

Nestedness of butterfly assemblages in the Zhoushan Archipelago, China: area effects, life-history traits and conservation implications

The nested subset pattern (nestedness) of faunal assemblages has been a research focus in the fields of island biogeography and conservation biology in recent decades. However, relatively few studies have described nestedness in butterfly assemblages in oceanic archipelago systems. Moreover, previous studies often quantified nestedness using inappropriate nestedness metrics and random fill algorithms with high Type I errors. The aims of this study are to examine the existence of nestedness and underlying causal mechanisms of butterfly assemblages in the Zhoushan Archipelago, China. We used the line-transect method to determine butterfly occupancy and abundance on 42 study islands from July to August 2014. We obtained butterfly life-history traits (wingspan, body weight and minimum area requirement) by field work and island geographical features (area and isolation) from the literature. We used the recently developed metric WNODF to estimate nestedness. Partial Spearman rank correlation was used to evaluate the associations of nestedness and island geographical features as well as butterfly life-history traits related to species extinction risk and colonization ability. The butterfly assemblages were significantly nested. Island area and minimum area requirement of butterflies were significantly correlated with nestedness after controlling for other independent variables. In contrast, the nestedness of butterflies did not appear to result from passive sampling or selective colonization. However, multi-year studies are needed to confirm that target effects are not muddling these results. Our results indicate that selective extinction may be the main driver of nestedness of butterfly assemblages in our study system. From a conservation viewpoint, we should protect both large islands and species with large area requirement to maximize the number of species preserved.

Does the National Resident Match Program Rank List Predict Success in Emergency Medicine Residency Programs?

BackgroundEmergency medicine (EM) residency programs use nonstandardized criteria to create applicant rank lists. One implicit assumption is that predictive associations exist between an applicant's rank and their future performance as a resident. To date, these associations have not been sufficiently demonstrated. ObjectivesWe hypothesized that a strong positive correlation exists between the National Resident Match Program (NRMP) match-list applicant rank, the United States Medical Licensing Examination (USMLE) Step 1 and In-Training Examination (ITE) scores, and the graduating resident rank. MethodsA total of 286 residents from five EM programs over a 5-year period were studied. The applicant rank (AR) was derived from the applicant's relative rank list position on each programs' submitted NRMP rank list. The graduation rank (GR) was determined by a faculty consensus committee. GR was then correlated to AR using a Spearman's partial rank correlation. Additional correlations were sought with a ranking of the USMLE Step Score (UR) and the ITE Score (IR). ResultsCombining data for all five programs, weak positive correlations existed between GR and AR, UR, and IR. The majority of correlations ranged between. When comparing GR and AR, there was a weak correlation of 0.13 (p = 0.03). ConclusionOur study found only weak correlations between GR and AR, UR, and IR, suggesting that those variables may not be strong predictors of resident performance. This has important implications for EM programs considering the resources devoted to applicant evaluation and ranking.

Influencing factors of the nested distribution of butterfly assemblages in the Zhoushan Archipelago, China

In natural ecosystem, species assemblages in fragmented habitats frequently exhibit a nested sub- set pattern. Although nestedness has been documented for a wide range of taxa, it is rarely tested in butterfly assemblages in oceanic archipelago ecosystems. We surveyed the butterfly occupancy and abundance on 28 islands using a line-transect method in the Zhoushan Archipelago, China from July to August 2013. We de- termined island geographical factors (area, isolation) based on the literature and obtained species life-history traits (area requirement, wingspan and body weight) in the laboratory. The recently developed metric WNODF was used to examine the nestedness. Partial Spearman rank correlation was used to evaluate the as- sociations of nestedness and island geographical factors as well as life-history traits related to species extinc- tion and immigration tendencies. We found that the community composition of butterflies in the Zhoushan Archipelago was significantly nested. Island area and species' area requirements were significantly correlated with nestedness after synthesis for all independent variables. In contrast, according to the null-model random test, nestedness of butterflies might not result from passive sampling or selective colonization. Our results in- dicate that selective extinction is the main driver of nestedness of butterflies in our system. From a conserva- tion perspective, we suggest that large islands and species with large area requirements should be paid more attention in order to maximize the total number of species preserved.

Associations between intake of fish and n-3 long-chain polyunsaturated fatty acids and plasma metabolites related to the kynurenine pathway in patients with coronary artery disease.

Enhanced tryptophan degradation via the kynurenine pathway has been related to several pathological conditions. However, little is known about the effect of diet on individual metabolites of this pathway. We investigated cross-sectional associations between reported intake of fish and omega-3 (n-3) long-chain PUFA (LC-PUFA) and plasma metabolites related to the kynurenine pathway. Participants were 2324 individuals with coronary artery disease from the Western Norway B Vitamin Intervention Trial. Fish and n-3 LC-PUFA intakes were assessed using a food frequency questionnaire. Plasma concentrations of tryptophan, kynurenine, kynurenic acid, anthranilic acid, 3-hydroxykynurenine, xanthurenic acid, 3-hydroxyanthranilic acid, neopterin, and kynurenine-to-tryptophan ratio (KTR) were analyzed. Associations were investigated using partial Spearman's rank correlations and multiple linear regressions. Median age at inclusion was 62years (80% males), and 84% had stable angina pectoris. Intake of fatty fish and n-3 LC-PUFA was inversely associated with plasma 3-hydroxykynurenine. Consumption of total fish, lean fish, and n-3 LC-PUFA was inversely associated with plasma neopterin. Intake of total fish, fatty fish, and n-3 LC-PUFA was inversely associated with KTR. All these correlations were weak (ρ between -0.12 and -0.06, P<0.01). In 306 patients with diabetes, lean fish intake was positively associated with plasma 3-hydroxyanthranilic acid (ρ=0.22, P<0.001, P for interaction=0.01), and total fish intake was inversely associated with KTR (ρ=-0.17, P<0.01, P for interaction=0.02). Fish intake was not an important determinant of individual metabolites in the kynurenine pathway. However, some correlations were stronger in patients with diabetes. The inverse associations of fish or n-3 LC-PUFA with neopterin and KTR may suggest a slightly lower IFN-γ-mediated immune activation with a higher intake.

Retinal Nerve Fiber Layer Thickness, Brain Atrophy, and Disability in Multiple Sclerosis Patients

To study the relationship between retinal nerve fiber layer (RNFL) thickness and brain atrophy using magnetic resonance imaging (MRI) with bicaudate ratio (BCR) in patients with multiple sclerosis (MS) with different levels of disease severity. We also assessed whether RNFL thickness correlated with Expanded Disability Status Scale (EDSS) score. The participants consisted of 88 patients with MS and 59 age- and sex-matched healthy control subjects. Eleven patients had clinically isolated syndrome (CIS), 68 patients had relapsing-remitting MS (RR-MS), and 9 patients had secondary progressive MS. Patients and controls were evaluated using optical coherence tomography (OCT, Cirrus) and scanning laser polarimetry with variable corneal compensation (GDx VCC). Patients underwent the same brain MRI scanning protocol. Disability was evaluated according to the EDSS. The BCR was calculated by dividing the minimum intercaudate distance by brain width along the same level. The BCR was higher in patients with MS (0.12 ± 0.03) than in controls (0.08 ± 0.009) (P < 0.001). OCT average RNFL thickness in patients with MS was significantly lower (84.51 ± 14.27 μm) than in control subjects (98.44 ± 6.83 μm). BCR was correlated with OCT average RNFL thickness (r = -0.48, P = 0.002) in patients with MS without optic neuritis. Significant correlations were found between average RNFL thickness and EDSS (r = -0.43, P = 0.003). Additionally, there were correlations between BCR with GDx parameters in patients with MS without optic neuritis. This study shows that RNFL thickness correlates with BCR and with MS subtypes. Additionally, our study indicates that OCT is better suited for MS assessment than GDx. We conclude that the damage of retinal axons appears related to brain damage in patients with MS.

Ties Adjusted Rank Correlation Coefficient

This paper proposes, develops and presents a method that may be used to adjust and correct sample estimates of the usual spearman rank correlation coefficient for the possible presence of tied observation in the sampled populations. Without these adjustments the sums of squares of ranks in the denominator of the usual expression for the estimation of spearman rank correlation coefficients are often over estimated if there are ties in the populations and no effort is made to correct and adjust for them especially if these ties are not few, resulting in inefficient, unreliable and often misleading estimates. The proposed method is shows to be easily modified and applied to estimate ties adjusted spearman partial rank correlation coefficient between any two populations holding observations from a third population at constant levels with all the populations adjusted for the possible presence of tied observations. The usual statistical tests for significance are also easily modified using the ties adjusted rank correlation coefficients in place of the unadjusted and usual rank correlation coefficients. The proposed method is illustrated with some sample data and shows to produce more efficient estimates than the usual ties unadjusted uncorrected spearman rank correlation coefficients.

Prostate-Specific Membrane Antigen Protein Expression in Tumor Tissue and Risk of Lethal Prostate Cancer

Overexpression of prostate-specific membrane antigen (PSMA) in tumor tissue and serum has been linked to increased risk of biochemical recurrence in surgically treated prostate cancer patients, but none of the studies have assessed its association with disease-specific mortality. We examined whether high PSMA protein expression in prostate tumor tissue was associated with lethal disease, and with tumor biomarkers of progression, among participants of two U.S.-based cohorts (n = 902, diagnosed 1983-2004). We used Cox proportional hazards regression to calculate multivariable HRs and 95% confidence intervals (CI) of lethal prostate cancer, defined as disease-specific death or development of distant metastases (n = 95). Partial Spearman rank correlation coefficients were used to correlate PSMA with tumor biomarkers. During an average 13 years of follow-up, higher PSMA expression at prostatectomy was significantly associated with lethal prostate cancer (age-adjusted HRQuartile(Q)4vs.Q1 = 2.42; Ptrend < 0.01). This association was attenuated and nonsignificant (multivariable-adjusted HRQ4vs.Q1 = 1.01; Ptrend = 0.52) after further adjusting for Gleason score and prostate-specific antigen (PSA) at diagnosis. High PSMA expression was significantly (P < 0.05) correlated with higher Gleason score and PSA at diagnosis, increased tumor angiogenesis, lower vitamin D receptor and androgen receptor expression, and absence of ets-related gene (ERG) expression. High tumor PSMA expression was not an independent predictor of lethal prostate cancer in the current study. PSMA expression likely captures, in part, malignant features of Gleason grade and tumor angiogenesis. PSMA is not a strong candidate biomarker for predicting prostate cancer-specific mortality in surgically treated patients.

AB0847 Comparison of treatment responses to TNF-blockers in axial spondyloarthritis patients with short vs long symptom duration

ObjectivesTo investigate the influence of disease duration on treatment response and on the correlation between improvement of patients’ symptoms and improvement in objective measures of inflammation in patients with axial...

Age and gender differences in correlations of leisure‐time, household, and work‐related physical activity with physical performance in older Japanese adults

This study aimed to compare relationships of leisure-time, household, and work-related physical activity (PA) with physical performance by age and gender in older Japanese adults. This cross-sectional study included 525 community-dwelling older adults (73.3 ± 5.2 years) recruited in 2009-2011 in Kasama City, rural Japan. We used the Physical Activity Scale for the Elderly to assess PA variables. Physical performance was evaluated by 11 performance tests: grip strength, single-leg balance, functional reach, sit-and-reach, standing time from long sitting position, sit-to-stand, timed up and go, habitual walk, hand working, and simple and choice reaction times. After adjusting for potential confounders, leisure-time PA in young-old (≤ 74 years) men correlated significantly with eight performance tests (absolute value of Spearman's partial rank correlation coefficient: r = 0.18-0.39), whereas in old-old (≥ 75 years) men it correlated with three performance tests (r = 0.20-0.23). Although leisure-time PA correlated with six performance tests (r = 0.19-0.22) in young-old women, there were no significant correlations between leisure-time PA and performance tests in old-old women. Household PA of young-old men (r = 0.20-0.23) and old-old women (r = 0.26-0.34) correlated with four performance tests. In old-old men and young-old women, no significant correlation was found between household PA and performance tests. Work-related PA did not relate significantly to any performance tests in any groups. This study showed that leisure-time PA is related to physical performance, especially in young-old men and women, and household PA is especially related in young-old men and old-old women. Our findings suggest that supporting strategies for maintaining physical functions would differ by gender and age.

Nestedness of bird assemblages on urban woodlots: Implications for conservation

Nestedness is a pattern frequently observed in fragmented systems and has important implications for conservation. The few existing nestedness studies in urban landscapes have focused on the resident and breeding birds, while little attention has been paid to the wintering birds. Using distribution data of 60 bird species collected on 20 urban woodlots in Hangzhou, China, we tested for the existence of the nestedness and the underlying mechanisms for breeding birds and wintering species separately. We used the line-transect method to survey bird occupancy and abundance on 20 woodlots. We used two recently developed metrics, WNODF and NODF, to estimate nestedness. We used partial Spearman rank correlations to examine the associations of nestedness and habitat variables (area, isolation, habitat richness and human disturbance). We also used information-theoretic methods based on Akaike Information Criterion (AIC) to determine ecological processes underlying nestedness. The community compositions of breeding birds and wintering species were all significantly nested. Habitat nestedness is the main driver of species nestedness for all the bird assemblages. Human disturbance played an important role in the development of species nestedness for breeding birds, but not for wintering species. Nestedness of all the bird assemblages was not due to passive sampling, selective extinction or selective colonization. From a conservation viewpoint, our results indicate that we should protect woodlots with diverse habitats priorly and refrain from using breeding birds and wintering species as surrogates for each other in developing conservation planning.

A Head View-Invariant Representation of Gaze Direction in Anterior Superior Temporal Sulcus

SummaryHumans show a remarkable ability to discriminate others' gaze direction, even though a given direction can be conveyed by many physically dissimilar configurations of different eye positions and head views. For example, eye contact can be signaled by a rightward glance in a left-turned head or by direct gaze in a front-facing head. Such acute gaze discrimination implies considerable perceptual invariance. Previous human research found that superior temporal sulcus (STS) responds preferentially to gaze shifts [1], but the underlying representation that supports such general responsiveness remains poorly understood. Using multivariate pattern analysis (MVPA) of human functional magnetic resonance imaging (fMRI) data, we tested whether STS contains a higher-order, head view-invariant code for gaze direction. The results revealed a finely graded gaze direction code in right anterior STS that was invariant to head view and physical image features. Further analyses revealed similar gaze effects in left anterior STS and precuneus. Our results suggest that anterior STS codes the direction of another's attention regardless of how this information is conveyed and demonstrate how high-level face areas carry out fine-grained, perceptually relevant discrimination through invariance to other face features.

Perceived Physical and Psychosocial Exposure and Health Symptoms of Dairy Farm Staff and Possible Associations with Dairy Cow Health

The aim of this study was to gain a deeper understanding of work-related physical and psychosocial exposure and health symptoms of farm staff working in indoor loose-housing dairy systems in Sweden, and to examine possible associations between exposure and health symptoms of farm staff and disease incidence in their dairy herds. A sample of 41 farm owners or managers and 20 directly employed farm workers participated, each from a Swedish dairy farm with loose-housed cows. Mailed questionnaires comprising 29 questions were used to create four separate indices representing physical exposure, psychosocial exposure, physical symptoms, and psychosocial symptoms. Cow herd incidence rates of common veterinary-reported clinical diseases were calculated based on official records. Partial Spearman rank correlation was used to analyze associations. The study confirmed that physical and psychosocial exposure and health symptoms are not uncommon among owners/managers and employed workers. The study also found that farm owners/managers experience more physical symptoms in dairy herds with lower cow disease incidence rates, while more frequent or intensive exposure to negative psychosocial work environment factors among employed dairy workers is associated with a high herd disease incidence rate.

BIODIVERSITY RESEARCH: Nestedness for different reasons: the distributions of birds, lizards and small mammals on islands of an inundated lake

AbstractAim We examined whether the community compositions of birds, lizards and small mammals were nested in a fragmented landscape in the Thousand Island Lake, China. We also assessed whether the mechanisms influencing nestedness differed among these taxonomic groups.Location Thousand Island Lake, China.Methods Presence/absence matrices were compiled for birds (42 islands) and lizards (42 islands) using line‐transect methods, and for small mammals (14 islands) using live‐trapping methods from 2006 to 2009. Nestedness was analysed using BINMATNEST, and statistical significance was assessed using the conservative null model 3. We used Spearman rank correlations and partial Spearman rank correlations to examine associations of nestedness and habitat variables (area, isolation, habitat diversity and plant richness) as well as life‐history traits (body size, habitat specificity, geographical range size and area requirement) related to species extinction and immigration tendencies.Results The community compositions of birds, lizards and small mammals were all significantly nested, but the causal factors underlying nestedness differed among taxonomic groups. For birds, island area, habitat specificity and area requirement were significantly correlated with nestedness after controlling for other independent variables. For lizards, habitat heterogeneity was the single best correlate of nestedness. For small mammals, island area, habitat heterogeneity and habitat specificity were significantly correlated with nestedness. The nested patterns of birds, lizards and small mammals were not attributable to passive sampling or selective colonization.Main conclusions The processes influencing nested patterns differed among taxonomic groups. Nestedness of bird assemblages was driven by selective extinction, and lizard assemblage was caused by habitat nestedness, while nestedness of small mammals resulted from both selective extinction and habitat nestedness. Therefore, we should take taxonomic differences into account when analysing nestedness to develop conservation guidelines and refrain from using single taxa as surrogates for others.