Dissociable contribution of prefrontal and striatal dopaminergic genes to learning in economic games

PubMed Central

Set, Eric; Saez, Ignacio; Zhu, Lusha; Houser, Daniel E.; Myung, Noah; Zhong, Songfa; Ebstein, Richard P.; Chew, Soo Hong; Hsu, Ming

2014-01-01

Game theory describes strategic interactions where success of players’ actions depends on those of coplayers. In humans, substantial progress has been made at the neural level in characterizing the dopaminergic and frontostriatal mechanisms mediating such behavior. Here we combined computational modeling of strategic learning with a pathway approach to characterize association of strategic behavior with variations in the dopamine pathway. Specifically, using gene-set analysis, we systematically examined contribution of different dopamine genes to variation in a multistrategy competitive game captured by (i) the degree players anticipate and respond to actions of others (belief learning) and (ii) the speed with which such adaptations take place (learning rate). We found that variation in genes that primarily regulate prefrontal dopamine clearance—catechol-O-methyl transferase (COMT) and two isoforms of monoamine oxidase—modulated degree of belief learning across individuals. In contrast, we did not find significant association for other genes in the dopamine pathway. Furthermore, variation in genes that primarily regulate striatal dopamine function—dopamine transporter and D2 receptors—was significantly associated with the learning rate. We found that this was also the case with COMT, but not for other dopaminergic genes. Together, these findings highlight dissociable roles of frontostriatal systems in strategic learning and support the notion that genetic variation, organized along specific pathways, forms an important source of variation in complex phenotypes such as strategic behavior. PMID:24979760

Dissociable contribution of prefrontal and striatal dopaminergic genes to learning in economic games.

PubMed

Set, Eric; Saez, Ignacio; Zhu, Lusha; Houser, Daniel E; Myung, Noah; Zhong, Songfa; Ebstein, Richard P; Chew, Soo Hong; Hsu, Ming

2014-07-01

Game theory describes strategic interactions where success of players' actions depends on those of coplayers. In humans, substantial progress has been made at the neural level in characterizing the dopaminergic and frontostriatal mechanisms mediating such behavior. Here we combined computational modeling of strategic learning with a pathway approach to characterize association of strategic behavior with variations in the dopamine pathway. Specifically, using gene-set analysis, we systematically examined contribution of different dopamine genes to variation in a multistrategy competitive game captured by (i) the degree players anticipate and respond to actions of others (belief learning) and (ii) the speed with which such adaptations take place (learning rate). We found that variation in genes that primarily regulate prefrontal dopamine clearance--catechol-O-methyl transferase (COMT) and two isoforms of monoamine oxidase--modulated degree of belief learning across individuals. In contrast, we did not find significant association for other genes in the dopamine pathway. Furthermore, variation in genes that primarily regulate striatal dopamine function--dopamine transporter and D2 receptors--was significantly associated with the learning rate. We found that this was also the case with COMT, but not for other dopaminergic genes. Together, these findings highlight dissociable roles of frontostriatal systems in strategic learning and support the notion that genetic variation, organized along specific pathways, forms an important source of variation in complex phenotypes such as strategic behavior.

Linking lowermost mantle structure, core-mantle boundary heat flux and mantle plume formation

NASA Astrophysics Data System (ADS)

Li, Mingming; Zhong, Shijie; Olson, Peter

2018-04-01

The dynamics of Earth's lowermost mantle exert significant control on the formation of mantle plumes and the core-mantle boundary (CMB) heat flux. However, it is not clear if and how the variation of CMB heat flux and mantle plume activity are related. Here, we perform geodynamic model experiments that show how temporal variations in CMB heat flux and pulses of mantle plumes are related to morphologic changes of the thermochemical piles of large-scale compositional heterogeneities in Earth's lowermost mantle, represented by the large low shear velocity provinces (LLSVPs). We find good correlation between the morphologic changes of the thermochemical piles and the time variation of CMB heat flux. The morphology of the thermochemical piles is significantly altered during the initiation and ascent of strong mantle plumes, and the changes in pile morphology cause variations in the local and the total CMB heat flux. Our modeling results indicate that plume-induced episodic variations of CMB heat flux link geomagnetic superchrons to pulses of surface volcanism, although the relative timing of these two phenomena remains problematic. We also find that the density distribution in thermochemical piles is heterogeneous, and that the piles are denser on average than the surrounding mantle when both thermal and chemical effects are included.

Variation in Chemotherapy Utilization in Ovarian Cancer: The Relative Contribution of Geography

PubMed Central

Polsky, Daniel; Armstrong, Katrina A; Randall, Thomas C; Ross, Richard N; Even-Shoshan, Orit; Rosenbaum, Paul R; Silber, Jeffrey H

2006-01-01

Objective This study investigates geographic variation in chemotherapy utilization for ovarian cancer in both absolute and relative terms and examines area characteristics associated with this variation. Data Sources Surveillance, Epidemiology, and End Results (SEER) Medicare data from 1990 to 2001 for Medicare patients over 65 with a diagnosis of ovarian cancer between 1990 and 1999. Chemotherapy within a year of diagnosis was identified by Medicare billing codes. The hospital referral region (HRR) represents the geographic unit of analysis. Study Design A logit model predicting the probability of receiving chemotherapy by each of the 39 HRRs. Control variables included medical characteristics (patient age, stage, year of diagnosis, and comorbidities) and socioeconomic characteristics (race, income, and education). The variation among HRRs was tested by the χ2 statistic, and the relative contribution was measured by the ω statistic. HHR market characteristic are then used to explain HRR-level variation. Principal Findings The average chemotherapy rate was 56.6 percent, with a range by HRR from 33 percent to 67 percent. There were large and significant differences in chemotherapy use between HRRs, reflected by a χ2 for HRR of 146 (df=38, p<.001). HRR-level variation in chemotherapy use can be partially explained by higher chemotherapy rates in HRRs with a higher percentage of hospitals with oncology services. However, an ω analysis indicates that, by about 15 to one, the variation between patients in use of chemotherapy reflects variations in patient characteristics rather than unexplained variation among HRRs. Conclusions While absolute levels of chemotherapy variation between geographic areas are large and statistically significant, this analysis suggests that the role of geography in determining who gets chemotherapy is small relative to individual medical characteristics. Nevertheless, while variation by medical characteristics can be medically justified, the same cannot be said for geographic variation. Our finding that density of oncology hospitals predicts chemotherapy use suggests that provider supply is positively correlated with geographic variation. PMID:17116116

Implications of temporal variation in maternal care for the prediction of neurobiological and behavioral outcomes in offspring

PubMed Central

Peña, Catherine Jensen; Champagne, Frances A.

2014-01-01

Previous studies in Long-Evans rats demonstrated a significant relationship between variation in pup licking/grooming and arched-back nursing (LG-ABN) and offspring development. However, maternal care is dynamic and exhibits significant temporal variation. In the current study, we assessed temporal variation in LG and ABN in lactating rats across the circadian cycle and determined the impact of these behaviors for the prediction of offspring hypothalamic gene expression, anxiety-like behavior, and responsiveness to high fat diet (HFD). We find that distinguishing between dams that engage in stable individual differences in maternal behavior (Low, Mid, High) requires assessment across the light-dark phases of the light cycle and across multiple postpartum days. Amongst juvenile female offspring, we find a positive correlation between maternal LG and mRNA levels of estrogen receptor alpha and beta and the oxytocin receptor (when LG is assessed across the light-dark cycle or in the dark phase). In young adults, we find sex-specific effects, with female High LG offspring exhibiting increased exploration of a novel environment and increased latency to approach HFD and male High LG offspring displaying increased activity in a novel environment and reduced HFD consumption. Importantly, these effects on behavior were primarily evident when LG was assessed across the light-dark cycle and ABN was not associated with these measures. Overall, our findings illustrate the dissociation between the effects of LG and ABN on offspring development and provide critical insights into the temporal characteristics of maternal behavior that have methodological implications for the study of maternal effects. PMID:23398440

Influence of Stuttering Variation on Talker Group Classification in Preschool Children: Preliminary Findings

ERIC Educational Resources Information Center

Johnson, Kia N.; Karrass, Jan; Conture, Edward G.; Walden, Tedra

2009-01-01

The purpose of this study was to investigate whether variations in disfluencies of young children who do (CWS) and do not stutter (CWNS) significantly change their talker group classification or diagnosis from stutterer to nonstutterer, and vice versa. Participants consisted of seventeen 3- to 5-year-old CWS and nine 3- to 5-year-old CWNS, with no…

Age- and gender-related regional variations of human brain cortical thickness, complexity, and gradient in the third decade.

PubMed

Creze, Maud; Versheure, Leslie; Besson, Pierre; Sauvage, Chloe; Leclerc, Xavier; Jissendi-Tchofo, Patrice

2014-06-01

Brain functional and cytoarchitectural maturation continue until adulthood, but little is known about the evolution of the regional pattern of cortical thickness (CT), complexity (CC), and intensity or gradient (CG) in young adults. We attempted to detect global and regional age- and gender-related variations of brain CT, CC, and CG, in 28 healthy young adults (19-33 years) using a three-dimensional T1 -weighted magnetic resonance imaging sequence and surface-based methods. Whole brain interindividual variations of CT and CG were similar to that in the literature. As a new finding, age- and gender-related variations significantly affected brain complexity (P < 0.01) on posterior cingulate and middle temporal cortices (age), and the fronto-orbital cortex (gender), all in the right hemisphere. Regions of interest analyses showed age and gender significant interaction (P < 0.05) on the temporopolar, inferior, and middle temporal-entorrhinal cortices bilaterally, as well as left inferior parietal. In addition, we found significant inverse correlations between CT and CC and between CT and CG over the whole brain and markedly in precentral and occipital areas. Our findings differ in details from previous reports and may correlate with late brain maturation and learning plasticity in young adults' brain in the third decade. Copyright © 2013 Wiley Periodicals, Inc.

Multivariate relationships between microbial communities and environmental variables during co-composting of sewage sludge and agricultural waste in the presence of PVP-AgNPs.

PubMed

Zhang, Lihua; Zhang, Jiachao; Zeng, Guangming; Dong, Haoran; Chen, Yaoning; Huang, Chao; Zhu, Yuan; Xu, Rui; Cheng, Yujun; Hou, Kunjie; Cao, Weicheng; Fang, Wei

2018-08-01

This study evaluated the contributions of environmental variables to the variations in bacterial 16S rDNA, nitrifying and denitrifying genes abundances during composting in the presence of polyvinylpyrrolidone coated silver nanoparticles (PVP-AgNPs). Manual forward selection in redundancy analysis (RDA) indicated that the variation in 16S rDNA was significantly explained by NO 3 - -N, while nitrifying genes were significantly related with pH, and denitrifying genes were driven by NO 3 - -N and TN. Partial RDA further revealed that NO 3 - -N solely explained 28.8% of the variation in 16S rDNA abundance, and pH accounted for 61.8% of the variation in nitrifying genes. NO 3 - -N and TN accounted for 34.2% and 9.2% of denitrifying genes variation, respectively. The RDA triplots showed that different genes shared different relationships with environmental parameters. Based on these findings, a composting with high efficiency and quality may be conducted in the future work by adjusting the significant environmental variables. Copyright © 2018 Elsevier Ltd. All rights reserved.

Genome-Wide Copy Number Variation Association Analyses for Age at Menarche

PubMed Central

Li, Jian; Pan, Rong; Shen, Hui; Tian, Qing; Zhou, Yu; Liu, Yong-Jun

2012-01-01

Context: Menarche is a significant physiological event for women. Age at menarche (AAM) is a heritable trait associated with many common female diseases. The genetic basis and the mechanism for AAM are largely unknown. Copy number variation (CNV) is a common type of genetic variation underlying human complex traits. The importance of CNV to AAM variation is unclear. Objective: The objective of the study was to identify CNV important to AAM variation. Design: We performed the first genome-wide CNV study of AAM in 1654 Caucasian females using Affymetrix human single-nucleotide polymorphism 6.0 array. We also replicated our findings in another Chinese cohort containing 752 women. Results: We identified a CNV, variation_38399, in the 2q14.2 region, for association with AAM (P = 1.03 × 10−3). The CNV has two variants (one copy and two copy), with a mean AAM of 14.00 yr and 12.90 yr, respectively. Interestingly, in a Chinese sample containing 752 women, this CNV has been replicated both with a marginally significant P = 0.090 and with a same direction of effect (a lower copy number for a later AAM). The CNV is located approximately 75 kb upstream of the diazepam binding inhibitor (DBI), a gene known to regulate estrogen levels, a key factor for menarche. Conclusion: Our findings for the first time identified a novel CNV and suggested the DBI-mediated endocrinological pathway as a potential mechanism for AAM regulation. PMID:22904172

Regional differences in prescribing quality among elder veterans and the impact of rural residence

PubMed Central

Lund, BC; Charlton, ME; Steinman, MA; Kaboli, PJ

2014-01-01

Purpose Medication safety is a critical concern for older adults. Regional variation in potentially inappropriate prescribing practices may reflect important differences in health care quality. Therefore, the objectives of this study were to characterize prescribing quality variation among older adults across geographic region, and to compare prescribing quality across rural versus urban residence. Methods Cross-sectional study of 1,549,824 older adult veterans with regular Veterans Affairs (VA) primary care and medication use during fiscal year 2007. Prescribing quality was measured by 4 indicators of potentially inappropriate prescribing: Zhan criteria drugs to avoid, Fick criteria drugs to avoid, therapeutic duplication, and drug-drug interactions. Frequency differences across region and rural-urban residence were compared using adjusted odds-ratios. Findings Significant regional variation was observed for all indicators. Zhan criteria frequencies ranged from 13.2% in the Northeast to 21.2% in the South. Nationally, rural veterans had a significantly increased risk for inappropriate prescribing according to all quality indicators. However, regional analyses revealed this effect was limited to the South and Northeast, whereas rural residence was neutral in the Midwest and protective in the West. Conclusions Significant regional variation in prescribing quality was observed among older adult veterans, mirroring recent findings among Medicare beneficiaries. The association between rurality and prescribing quality is heterogeneous, and relying solely on national estimates may yield misleading conclusions. While we documented important variations in prescribing quality, the underlying factors driving these trends remain unknown, and they are a vital area for future research affecting older adults in both VA and non-VA health systems. PMID:23551647

Temporal variation of out-of-hospital cardiac arrests in an equatorial climate.

PubMed

Ong, Marcus Eh; Ng, Faith Sp; Yap, Susan; Yong, Kok Leong; Peberdy, Mary A; Ornato, Joseph P

2010-01-01

We aimed to determine whether there is a seasonal variation of out-of-hospital cardiac arrests (OHCA) in an equatorial climate, which does not experience seasonal environmental change. We conducted an observational prospective study looking at the occurrence of OHCA in Singapore. Included were all patients with OHCA presented to Emergency Departments across the country. We examined the monthly, daily, and hourly number of cases over a three-year period. Data was analyzed using analysis of variance (ANOVA). From October, 1st 2001 to October, 14th 2004, 2428 patients were enrolled in the study. Mean age for cardiac arrests was 60.6 years with 68.0% male. Ethnic distribution was 69.5% Chinese, 15.0% Malay, 11.0% Indian, and 4.4% Others. There was no significant seasonal variation (spring/summer/fall/winter) of events (ANOVA P = 0.71), monthly variation (P = 0.88) or yearly variation (P = 0.26). We did find weekly peaks on Mondays and a circadian pattern with daily peaks from 9-10 am. We did not find any discernable seasonal pattern of cardiac arrests. This contrasts with findings from temperate countries and suggests a climatic influence on cardiac arrest occurrence. We also found that sudden cardiac arrests follow a circadian pattern.

Variations in Vietnamese marriages, births and infant deaths by months of the Julian calendar and years of the Vietnamese and Chinese astrological calendars.

PubMed

Nguyen, M T; Swenson, I

1996-07-01

The timing of births and marriages in Vietnam appears to have some statistically significant relationships with the signs of the Chinese and Vietnamese astrological calendars. Years considered to be good years have significantly more births and marriages than years that are not considered as desirable. Births and marriages also have some significant variations with seasons of the year. Infant deaths do not appear to have any significant relationships with the astrological signs although infant mortality has some significant relationships with seasons of the year. The findings indicate that there is some purposeful planning for marriages and births to coincide with optimal times defined in the astrological calendars.

The genetic diversity and epizootiology of infectious hematopoietic necrosis virus

USGS Publications Warehouse

Oshima, Kevin H.; Arakawa, Cindy K.; Higman, Keith H.; Landolt, Marsha L.; Nichol, Stuart T.; Winton, James R.

1994-01-01

Infectious hematopoietic necrosis virus (IHNV) is a rhabdovirus which causes a serious disease in salmondd fish. The T1 ribonuclease fingerprinttin method was used to compare the RNA genomes of 26 isolates of IHNV recovered from sockeye salmon (Oncorhynchus nerka), chinook salmon (O. tshawytscha), and steelhead trout (O. mykiss) throughout the enzootic portion of western North America. Most of the isolates as a source of genetic variation. In from a single year (1987) to limit time of isolation as a source of genetic variation. In addition, isolates from different years collected at three sites were analyzed to investigate genetic drift or evolution of IHNV within specific locations. All of the isolates examined by T1 fingerprint analysis contained less than a 50% variation in spot location and were represented by a single fingerprint group. The observed variation was estimated to correspond to less than 5% variation in the nucleic acid sequence. However, sufficient variation was detected to separate the isolates into four subgroups which appeared to correlate to different geographic regions. Host species appeared not to be a significant source of variation. The evolutionary and epizootiologic significance of these findings and their relationship to other evidence of genetic variation in IHNV isolates are discussed.

The Effect of Marital Breakup on the Income Distribution of Women with Children

ERIC Educational Resources Information Center

Ananat, Elizabeth O.; Michaels, Guy

2008-01-01

Having a female first-born child significantly increases the probability that a woman's first marriage breaks up. Using this exogenous variation, recent work finds that divorce has little effect on women's mean household income. We further investigate the effect of divorce using Quantile Treatment Effect methodology and find that it increases…

Genetic interactions contribute less than additive effects to quantitative trait variation in yeast

PubMed Central

Bloom, Joshua S.; Kotenko, Iulia; Sadhu, Meru J.; Treusch, Sebastian; Albert, Frank W.; Kruglyak, Leonid

2015-01-01

Genetic mapping studies of quantitative traits typically focus on detecting loci that contribute additively to trait variation. Genetic interactions are often proposed as a contributing factor to trait variation, but the relative contribution of interactions to trait variation is a subject of debate. Here we use a very large cross between two yeast strains to accurately estimate the fraction of phenotypic variance due to pairwise QTL–QTL interactions for 20 quantitative traits. We find that this fraction is 9% on average, substantially less than the contribution of additive QTL (43%). Statistically significant QTL–QTL pairs typically have small individual effect sizes, but collectively explain 40% of the pairwise interaction variance. We show that pairwise interaction variance is largely explained by pairs of loci at least one of which has a significant additive effect. These results refine our understanding of the genetic architecture of quantitative traits and help guide future mapping studies. PMID:26537231

Anatomic variation of depth-dependent mechanical properties in neonatal bovine articular cartilage.

PubMed

Silverberg, Jesse L; Dillavou, Sam; Bonassar, Lawrence; Cohen, Itai

2013-05-01

Articular cartilage has well known depth-dependent structure and has recently been shown to have similarly non-uniform depth-dependent mechanical properties. Here, we study anatomic variation of the depth-dependent shear modulus and energy dissipation rate in neonatal bovine knees. The regions we specifically focus on are the patellofemoral groove, trochlea, femoral condyle, and tibial plateau. In every sample, we find a highly compliant region within the first 500 µm of tissue measured from the articular surface, where the local shear modulus is reduced by up to two orders of magnitude. Comparing measurements taken from different anatomic sites, we find statistically significant differences localized within the first 50 µm. Histological images reveal these anatomic variations are associated with differences in collagen density and fiber organization. Copyright © 2012 Orthopaedic Research Society.

A Sustained Dietary Change Increases Epigenetic Variation in Isogenic Mice

PubMed Central

Cowley, Mark J.; Preiss, Thomas; Martin, David I. K.; Suter, Catherine M.

2011-01-01

Epigenetic changes can be induced by adverse environmental exposures, such as nutritional imbalance, but little is known about the nature or extent of these changes. Here we have explored the epigenomic effects of a sustained nutritional change, excess dietary methyl donors, by assessing genomic CpG methylation patterns in isogenic mice exposed for one or six generations. We find stochastic variation in methylation levels at many loci; exposure to methyl donors increases the magnitude of this variation and the number of variable loci. Several gene ontology categories are significantly overrepresented in genes proximal to these methylation-variable loci, suggesting that certain pathways are susceptible to environmental influence on their epigenetic states. Long-term exposure to the diet (six generations) results in a larger number of loci exhibiting epigenetic variability, suggesting that some of the induced changes are heritable. This finding presents the possibility that epigenetic variation within populations can be induced by environmental change, providing a vehicle for disease predisposition and possibly a substrate for natural selection. PMID:21541011

Female guppies agree to differ: phenotypic and genetic variation in mate-choice behavior and the consequences for sexual selection.

PubMed

Brooks, R; Endler, J A

2001-08-01

Variation among females in mate choice may influence evolution by sexual selection. The genetic basis of this variation is of interest because the elaboration of mating preferences requires additive genetic variation in these traits. Here we measure the repeatability and heritability of two components of female choosiness (responsiveness and discrimination) and of female preference functions for the multiple ornaments borne by male guppies (Poecilia reticulata). We show that there is significant repeatable variation in both components of choosiness and in some preference functions but not in others. There appear to be several male ornaments that females find uniformly attractive and others for which females differ in preference. One consequence is that there is no universally attractive male phenotype. Only responsiveness shows significant additive genetic variation. Variation in responsiveness appears to mask variation in discrimination and some preference functions and may be the most biologically relevant source of phenotypic and genetic variation in mate-choice behavior. To test the potential evolutionary importance of the phenotypic variation in mate choice that we report, we estimated the opportunity for and the intensity of sexual selection under models of mate choice that excluded and that incorporated individual female variation. We then compared these estimates with estimates based on measured mating success. Incorporating individual variation in mate choice generally did not predict the outcome of sexual selection any better than models that ignored such variation.

Large-scale Observations of a Subauroral Polarization Stream by Midlatitude SuperDARN Radars: Instantaneous Longitudinal Velocity Variations

NASA Technical Reports Server (NTRS)

Clausen, L. B. N.; Baker, J. B. H.; Sazykin, S.; Ruohoniemi, J. M.; Greenwald, R. A.; Thomas, E. J.; Shepherd, S. G.; Talaat, E. R.; Bristow, W. A.; Zheng, Y.;

Genome-wide variation in recombination rate in Eucalyptus.

PubMed

Gion, Jean-Marc; Hudson, Corey J; Lesur, Isabelle; Vaillancourt, René E; Potts, Brad M; Freeman, Jules S

2016-08-09

Meiotic recombination is a fundamental evolutionary process. It not only generates diversity, but influences the efficacy of natural selection and genome evolution. There can be significant heterogeneity in recombination rates within and between species, however this variation is not well understood outside of a few model taxa, particularly in forest trees. Eucalypts are forest trees of global economic importance, and dominate many Australian ecosystems. We studied recombination rate in Eucalyptus globulus using genetic linkage maps constructed in 10 unrelated individuals, and markers anchored to the Eucalyptus reference genome. This experimental design provided the replication to study whether recombination rate varied between individuals and chromosomes, and allowed us to study the genomic attributes and population genetic parameters correlated with this variation. Recombination rate varied significantly between individuals (range = 2.71 to 3.51 centimorgans/megabase [cM/Mb]), but was not significantly influenced by sex or cross type (F1 vs. F2). Significant differences in recombination rate between chromosomes were also evident (range = 1.98 to 3.81 cM/Mb), beyond those which were due to variation in chromosome size. Variation in chromosomal recombination rate was significantly correlated with gene density (r = 0.94), GC content (r = 0.90), and the number of tandem duplicated genes (r = -0.72) per chromosome. Notably, chromosome level recombination rate was also negatively correlated with the average genetic diversity across six species from an independent set of samples (r = -0.75). The correlations with genomic attributes are consistent with findings in other taxa, however, the direction of the correlation between diversity and recombination rate is opposite to that commonly observed. We argue this is likely to reflect the interaction of selection and specific genome architecture of Eucalyptus. Interestingly, the differences amongst chromosomes in recombination rates appear stable across Eucalyptus species. Together with the strong correlations between recombination rate and features of the Eucalyptus reference genome, we maintain these findings provide further evidence for a broad conservation of genome architecture across the globally significant lineages of Eucalyptus.

An X-ray method for detecting substructure in galaxy clusters - Application to Perseus, A2256, Centaurus, Coma, and Sersic 40/6

NASA Technical Reports Server (NTRS)

Mohr, Joseph J.; Fabricant, Daniel G.; Geller, Margaret J.

1993-01-01

We use the moments of the X-ray surface brightness distribution to constrain the dynamical state of a galaxy cluster. Using X-ray observations from the Einstein Observatory IPC, we measure the first moment FM, the ellipsoidal orientation angle, and the axial ratio at a sequence of radii in the cluster. We argue that a significant variation in the image centroid FM as a function of radius is evidence for a nonequilibrium feature in the intracluster medium (ICM) density distribution. In simple terms, centroid shifts indicate that the center of mass of the ICM varies with radius. This variation is a tracer of continuing dynamical evolution. For each cluster, we evaluate the significance of variations in the centroid of the IPC image by computing the same statistics on an ensemble of simulated cluster images. In producing these simulated images we include X-ray point source emission, telescope vignetting, Poisson noise, and characteristics of the IPC. Application of this new method to five Abell clusters reveals that the core of each one has significant substructure. In addition, we find significant variations in the orientation angle and the axial ratio for several of the clusters.

Developmental Change and Time-Specific Variation in Global and Specific Aspects of Self-Concept in Adolescence and Association with Depressive Symptoms

PubMed Central

Kuzucu, Yasar; Bontempo, Daniel E.; Hofer, Scott M.; Stallings, Michael C.; Piccinin, Andrea M.

2014-01-01

Previous research has demonstrated that adolescents make differential self-evaluations in multiple domains that include physical appearance, academic competence, and peer acceptance. We report growth curve analyses over a seven year period from age 9 to age 16 on the six domains of the Harter Self-Perception Profile for Children. In general, we find little change in self-concept, on average, but do find substantial individual differences in level, rate of change, and time-specific variation in these self- evaluations. The results suggest that sex differences and adoptive status were related to only certain aspects of the participants’ self-concept. Depressive symptoms were found to have significant effects on individual differences in rate of change and on time-specific variation in general self-concept, as well as on some of the specific domains of self-concept. PMID:25143664

Variations in 30-day readmissions and length of stay among spine surgeons: a national study of elective spine surgery among US Medicare beneficiaries.

PubMed

Singh, Siddhartha; Sparapani, Rodney; Wang, Marjorie C

2018-06-01

OBJECTIVE Pay-for-performance programs are targeting hospital readmissions. These programs have an underlying assumption that readmissions are due to provider practice patterns that can be modified by a reduction in reimbursement. However, there are limited data to support the role of providers in influencing readmissions. To study this, the authors examined variations in readmission rates by spine surgeon within 30 days among Medicare beneficiaries undergoing elective lumbar spine surgery for degenerative conditions. METHODS The authors applied validated ICD-9-CM algorithms to 2003-2007 Medicare data to select beneficiaries undergoing elective inpatient lumbar spine surgery for degenerative conditions. Mixed models, adjusting for patient demographics, comorbidities, and surgery type, were used to estimate risk of 30-day readmission by the surgeon. Length of stay (LOS) was also studied using these same models. RESULTS A total of 39,884 beneficiaries were operated on by 3987 spine surgeons. The mean readmission rate was 7.2%. The mean LOS was 3.1 days. After adjusting for patient characteristics and surgery type, 1 surgeon had readmission rates significantly below the mean, and only 5 surgeons had readmission rates significantly above the mean. In contrast, for LOS, the patients of 288 surgeons (7.2%) had LOS significantly lower than the mean, and the patients of 397 surgeons (10.0%) had LOS significantly above the mean. These findings were robust to adjustments for surgeon characteristics and clustering by hospital. Similarly, hospital characteristics were not significantly associated with readmission rates, but LOS was associated with hospital for-profit status and size. CONCLUSIONS The authors found almost no variations in readmission rates by surgeon. These findings suggest that surgeon practice patterns do not affect the risk of readmission. Likewise, no significant variation in readmission rates by hospital characteristics were found. Strategies to reduce readmissions would be better targeted at factors other than providers.

Morphometric variations of the 7th cervical vertebrae of Zulu, White, and Colored South Africans.

PubMed

Kibii, Job M; Pan, Rualing; Tobias, Phillip V

2010-05-01

The 7th cervical vertebrae of 240 cadavers of South African Zulu, White, and Colored population groups were examined to determine morphometric variation. White and Colored females had statistically significant narrower cervical anteroposterior diameters than their male counterparts, whereas no statistically significant difference between sexes of the Zulu population group was observed in this variable. In addition, although Zulu and Colored females had statistically significant narrower cervical transverse diameters than their male counterparts, there was no statistically significant variation between South African white males and females in this respect. The findings indicate that sexual dimorphism is more apparent in the vertebral centrum, across the three population groups, where males had significantly larger dimensions in centrum anteroposterior diameter, height, and width than their female counterparts. The study further reveals that sexual dimorphism is more apparent when one compares aspects of the 7th cervical vertebra between sexes within the same population group. Overall, the dimensions of the various variates of the vertebra are substantially smaller in women than in men. The smaller dimensions, particularly of the centrum, may be the result of lower skeletal mass in women and render them more vulnerable to fractures resulting from compression forces. 2010 Wiley-Liss, Inc.

Optimizing Experimental Designs: Finding Hidden Treasure.

USDA-ARS?s Scientific Manuscript database

Classical experimental design theory, the predominant treatment in most textbooks, promotes the use of blocking designs for control of spatial variability in field studies and other situations in which there is significant variation among heterogeneity among experimental units. Many blocking design...

Limits on Line Bisector Variability for Stars with Extrasolar Planets

NASA Technical Reports Server (NTRS)

Povich, M. S.; Giampapa, M. S.; Valenti, J. A.; Tilleman, T.; Barden, S.; Deming, D.; Livingston, W. C.; Pilachowski, C.

2000-01-01

We present an analysis of high-resolution synoptic spectra of ten F- and G-type stars, seven of which exhibit periodic radial velocity variations due to the presence of one or more substellar companions. We searched for subtle periodic variations in photospheric line asymmetry, as characterized by line bisectors. In principle, periodic variations in line asymmetry observed at lower spectral resolution could mimic the radial velocity signature of a companion, but we find no significant evidence of such behavior in our data. Observations were obtained from 1998 March to 1999 February using the National Solar Observatory (NSO) 1.52-m McMath-Pierce Solar Telescope Facility on Kitt Peak in conjunction with the solar-stellar spectrograph, achieving a resolving power of 1.2x10(exp5). To characterize line asymmetry, we first measured line bisectors for the unblended Fe I photospheric line at 625.26 nm. To improve sensitivity to small fluctuations, we then combined points in each bisector to form a velocity displacement with respect to the line core. We searched for periodic variations in this displacement, finding no substantial difference between stars with substellar companions and those without reported companions. We find no correlation between bisector velocity displacement and the known orbital phase of substellar companions around our target stars. Simulations of a periodic signal with noise levels that mimic our measurement errors suggest that we can exclude bisector variations with amplitudes greater than about 20 m/s. These results support the conclusion that extrasolar planets best explain the observed periodic variations in radial velocity.

Neighborhood influences on the association between maternal age and birthweight: a multilevel investigation of age-related disparities in health.

PubMed

Cerdá, Magdalena; Buka, Stephen L; Rich-Edwards, Janet W

2008-05-01

It was hypothesized that the relationship between maternal age and infant birthweight varies significantly across neighborhoods and that such variation can be predicted by neighborhood characteristics. We analyzed 229,613 singleton births of mothers aged 20-45 years from Chicago, USA in 1997-2002. Random coefficient models were used to estimate the between-neighborhood variation in age-birthweight slopes, and both intercepts- and-slopes-as-outcomes models were used to evaluate area-level predictors of such variation. The crude maternal age-birthweight slopes for neighborhoods ranged from a decrease of 17 g to an increase of 10 g per year of maternal age. Adjustment for individual-level covariates reduced but did not eliminate this between-neighborhood variation. Concentrated poverty was a significant neighborhood-level predictor of the age-birthweight slope, explaining 44.4% of the between-neighborhood variation in slopes. Neighborhoods of higher economic disadvantage showed a more negative age-birthweight slope. The findings support the hypothesis that the relationship between maternal age and birthweight varies between neighborhoods. Indicators of neighborhood disadvantage help to explain such differences.

Genetic and Environmental Influences on Individual Differences in Attitudes Toward Homosexuality: An Australian Twin Study

PubMed Central

Shekar, Sri N.; Zietsch, Brendan P.; Eaves, Lindon J.; Bailey, J. Michael; Boomsma, Dorret I.; Martin, Nicholas G.

2008-01-01

Previous research has shown that many heterosexuals hold negative attitudes toward homosexuals and homosexuality (homophobia). Although a great deal of research has focused on the profile of homophobic individuals, this research provides little theoretical insight into the aetiology of homophobia. To examine genetic and environmental influences on variation in attitudes toward homophobia, we analysed data from 4,688 twins who completed a questionnaire concerning sexual behaviour and attitudes, including attitudes toward homosexuality. Results show that, in accordance with literature, males have significantly more negative attitudes toward homosexuality than females and non-heterosexuals are less homophobic than heterosexuals. In contrast with some earlier findings, age had no significant effect on the homophobia scores in this study. Genetic modelling showed that variation in homophobia scores could be explained by additive genetic (36%), shared environmental (18%) and unique environmental factors (46%). However, corrections based on previous findings show that the shared environmental estimate may be almost entirely accounted for as extra additive genetic variance arising from assortative mating for homophobic attitudes. The results suggest that variation in attitudes toward homosexuality is substantially inherited, and that social environmental influences are relatively minor. PMID:18347968

Quantitative descriptive analysis and principal component analysis for sensory characterization of Indian milk product cham-cham.

PubMed

Puri, Ritika; Khamrui, Kaushik; Khetra, Yogesh; Malhotra, Ravinder; Devraja, H C

2016-02-01

Promising development and expansion in the market of cham-cham, a traditional Indian dairy product is expected in the coming future with the organized production of this milk product by some large dairies. The objective of this study was to document the extent of variation in sensory properties of market samples of cham-cham collected from four different locations known for their excellence in cham-cham production and to find out the attributes that govern much of variation in sensory scores of this product using quantitative descriptive analysis (QDA) and principal component analysis (PCA). QDA revealed significant (p < 0.05) difference in sensory attributes of cham-cham among the market samples. PCA identified four significant principal components that accounted for 72.4 % of the variation in the sensory data. Factor scores of each of the four principal components which primarily correspond to sweetness/shape/dryness of interior, surface appearance/surface dryness, rancid and firmness attributes specify the location of each market sample along each of the axes in 3-D graphs. These findings demonstrate the utility of quantitative descriptive analysis for identifying and measuring attributes of cham-cham that contribute most to its sensory acceptability.

ULTRAVIOLET EXTINCTION AT HIGH GALACTIC LATITUDES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peek, J. E. G.; Schiminovich, David, E-mail: jegpeek@gmail.com

In order to study the properties and effects of high Galactic latitude dust, we present an analysis of 373,303 galaxies selected from the Galaxy Evolution Explorer All-Sky Survey and Wide-field Infrared Explorer All-Sky Data Release. By examining the variation in aggregate ultraviolet colors and number density of these galaxies, we measure the extinction curve at high latitude. We additionally consider a population of spectroscopically selected galaxies from the Sloan Digital Sky Survey to measure extinction in the optical. We find that dust at high latitude is neither quantitatively nor qualitatively consistent with standard reddening laws. Extinction in the FUV andmore » NUV is {approx}10% and {approx}35% higher than expected, with significant variation across the sky. We find that no single R{sub V} parameter fits both the optical and ultraviolet extinction at high latitude, and that while both show detectable variation across the sky, these variations are not related. We propose that the overall trends we detect likely stem from an increase in very small silicate grains in the interstellar medium.« less

Multiple variations of the coeliac axis, hepatic and renal vasculature as incidental findings illustrated by MDCTA.

PubMed

Rafailidis, Vasileios; Papadopoulos, Georgios; Kouskouras, Konstantinos; Chryssogonidis, Ioannis; Velnidou, Anastasia; Kalogera-Fountzila, Anna

2016-08-01

Vascular anatomical variations are not uncommon and may affect any organ's arterial or venous vasculature. The coexistence of variations in different organic systems is less commonly found, but of great clinical significance in a series of clinical conditions like organ transplantation and surgical preoperative planning. Multidetector computed tomography angiography (MDCTA) has emerged as a valuable alternative to the conventional angiography for accurate evaluation of vascular anatomy and pathology. Radiologists should be familiar with each organ's vascular variations and always report them to the clinician, even if they represent an incidental finding. This case report presents a 52-year-old female patient undergoing abdominal MDCTA for characterization of a renal lesion. This examination revealed the presence of three hilar arteries on the left kidney, a main renal vein in combination with an additional renal vein in both sides along with a replaced right hepatic artery originating from the superior mesenteric artery. Moreover, both inferior phrenic arteries were found originating from the coeliac axis. 3D volume rendering technique images were used in the evaluation of vascular anatomy as illustrated in this case report.

Seasonal variation in blood and muscle oxygen stores attributed to diving behavior, environmental temperature and pregnancy in a marine predator, the California sea lion.

PubMed

Villegas-Amtmann, Stella; Atkinson, Shannon; Paras-Garcia, Alberto; Costa, Daniel P

2012-08-01

Survival depends on an animal's ability to find and acquire prey. In diving vertebrates, this ability is directly related to their physiological capability (e.g. oxygen stores). We studied the seasonal variation in oxygen stores, body temperature and body condition in California sea lions (Zalophus californianus) (CSL) as a function of seasonal variation in temperature, primary productivity, diving behavior and reproductive stage. During summer, blood oxygen stores were significantly greater and muscle oxygen stores were significantly lower than in winter. Total oxygen stores, body condition and body temperature did not change between seasons but variations in body temperature were greater during summer. Changes in oxygen stores are partly attributed to diving behavior, temperature and pregnancy that could increase oxygen consumption. Blood and muscle oxygen stores appear to be influenced by reproductive state. Blood oxygen stores are more likely influenced by diving behavior and temperature than muscle oxygen stores. Copyright © 2012 Elsevier Inc. All rights reserved.

Cortical Folding of the Primate Brain: An Interdisciplinary Examination of the Genetic Architecture, Modularity, and Evolvability of a Significant Neurological Trait in Pedigreed Baboons (Genus Papio)

PubMed Central

Atkinson, Elizabeth G.; Rogers, Jeffrey; Mahaney, Michael C.; Cox, Laura A.; Cheverud, James M.

2015-01-01

Folding of the primate brain cortex allows for improved neural processing power by increasing cortical surface area for the allocation of neurons. The arrangement of folds (sulci) and ridges (gyri) across the cerebral cortex is thought to reflect the underlying neural network. Gyrification, an adaptive trait with a unique evolutionary history, is affected by genetic factors different from those affecting brain volume. Using a large pedigreed population of ∼1000 Papio baboons, we address critical questions about the genetic architecture of primate brain folding, the interplay between genetics, brain anatomy, development, patterns of cortical–cortical connectivity, and gyrification’s potential for future evolution. Through Mantel testing and cluster analyses, we find that the baboon cortex is quite evolvable, with high integration between the genotype and phenotype. We further find significantly similar partitioning of variation between cortical development, anatomy, and connectivity, supporting the predictions of tension-based models for sulcal development. We identify a significant, moderate degree of genetic control over variation in sulcal length, with gyrus-shape features being more susceptible to environmental effects. Finally, through QTL mapping, we identify novel chromosomal regions affecting variation in brain folding. The most significant QTL contain compelling candidate genes, including gene clusters associated with Williams and Down syndromes. The QTL distribution suggests a complex genetic architecture for gyrification with both polygeny and pleiotropy. Our results provide a solid preliminary characterization of the genetic basis of primate brain folding, a unique and biomedically relevant phenotype with significant implications in primate brain evolution. PMID:25873632

Intraspecific variation in flight metabolic rate in the bumblebee Bombus impatiens: repeatability and functional determinants in workers and drones.

PubMed

Darveau, Charles-A; Billardon, Fannie; Bélanger, Kasandra

2014-02-15

The evolution of flight energetics requires that phenotypes be variable, repeatable and heritable. We studied intraspecific variation in flight energetics in order to assess the repeatability of flight metabolic rate and wingbeat frequency, as well as the functional basis of phenotypic variation in workers and drones of the bumblebee species Bombus impatiens. We showed that flight metabolic rate and wingbeat frequency were highly repeatable in workers, even when controlling for body mass variation using residual analysis. We did not detect significant repeatability in drones, but a smaller range of variation might have prevented us from finding significant values in our sample. Based on our results and previous findings, we associated the high repeatability of flight phenotypes in workers to the functional links between body mass, thorax mass, wing size, wingbeat frequency and metabolic rate. Moreover, differences between workers and drones were as predicted from these functional associations, where drones had larger wings for their size, lower wingbeat frequency and lower flight metabolic rate. We also investigated thoracic muscle metabolic phenotypes by measuring the activity of carbohydrate metabolism enzymes, and we found positive correlations between mass-independent metabolic rate and the activity of all enzymes measured, but in workers only. When comparing workers and drones that differ in flight metabolic rate, only the activity of the enzymes hexokinase and trehalase showed the predicted differences. Overall, our study indicates that there should be correlated evolution among physiological phenotypes at multiple levels of organization and morphological traits associated with flight.

Seasonal variation and meteotropism in various self-rated psychological and physiological features of a normal couple

NASA Astrophysics Data System (ADS)

Maes, Michael; de Meyer, Frans; Peeters, Dirk; Meltzer, Herbert; Cosyns, Paul; Schotte, Chris

1992-12-01

Recently, true seasonal variation with significant periodicities (circannual, semiannual, circatrimensual, circabimensual) and a significant meteotropism have been observed in a number of self-rated characteristics of normal man (arousal, mood, physiology and social behaviour). In order to replicate these findings, two normal controls (a married couple) were asked daily to complete a self-rating scale concerned with the characteristics mentioned above during one calendar year. By means of time series analysis, significant rhythmicities with recurrent cycles in the autorhythmometric data of all of the above characteristics were found. An important part of the variance in these characteristics was found, using multiple regression, to be related to various weather variables, such as mean atmospheric pressure, temperature, relative humidity, wind speed, minutes of sunlight/day and precipitation/day. These results support the hypothesis that temporal variations in human psychological and physiological characteristics may be dictated by the composite effects of past and present atmospheric activity.

Spatial distribution of SPAD value and determination of the suitable leaf for N diagnosis in cucumber

NASA Astrophysics Data System (ADS)

Hu, Jing; Li, Chenxiao; Wen, Yifang; Gao, Xinhao; Shi, Feifei; Han, Luhua

2018-01-01

To determine the best leaf position for nitrogen diagnosis in cucumber with SPAD meter, greenhouse experiments were carried out to study spatial distribution of SPAD value of different position of the 3rd fully expanded cucumber leaf in the effect of different nitrogen levels, and the correlations between SPAD values and nitrogen concentration of chlorophyll. The results show that there is remarkable different SPAD value in different positions of the 3rd fully expanded leaf in the flowering and fruiting stage. Comparing the coefficients of SPAD value variation, we find that the coefficient of variation of leaf edge was significantly higher than the edge of the main vein, and the coefficient of variation of triangular area of leaf tip is significantly higher than any other leaf area. There is a significant correlation between SPAD values and leaf nitrogen content. Preliminary study shows that triangular area of leaf tip from the 20% leaf tip to leaf edge is the best position for nitrogen diagnosis.

On the colour variations of negative superhumps

NASA Astrophysics Data System (ADS)

Imada, Akira; Yanagisawa, Kenshi; Kawai, Nobuyuki

2018-06-01

We present simultaneous g΄, Rc, and Ic photometry of the notable dwarf nova ER UMa during the 2011 season. Our photometry revealed that the brightness maxima of negative superhumps coincide with the bluest peaks in g΄ - Ic colour variations. We also found that the amplitudes of negative superhumps are the largest in the g΄ band. These observed properties are significantly different from those observed in early and positive superhumps. Our findings are consistent with a tilted disk model as the light source of negative superhumps.

Norms and Construct Validity of the Rosenberg Self-Esteem Scale in Canadian High School Populations: Implications for Counselling.

ERIC Educational Resources Information Center

Bagley, Christopher; Bolitho, Floyd; Bertrand, Lorne

1997-01-01

Reports on instrument validity regarding self-esteem among high school students (N=2,108) in the Province of Alberta. Results indicate significant variation of mean scores across age-groups within female students even though females had significantly lower self-esteem than males. Findings support the reliability of the self-esteem instrument. (RJM)

Genetic Variation in the Nuclear and Organellar Genomes Modulates Stochastic Variation in the Metabolome, Growth, and Defense

PubMed Central

Joseph, Bindu; Corwin, Jason A.; Kliebenstein, Daniel J.

2015-01-01

Recent studies are starting to show that genetic control over stochastic variation is a key evolutionary solution of single celled organisms in the face of unpredictable environments. This has been expanded to show that genetic variation can alter stochastic variation in transcriptional processes within multi-cellular eukaryotes. However, little is known about how genetic diversity can control stochastic variation within more non-cell autonomous phenotypes. Using an Arabidopsis reciprocal RIL population, we showed that there is significant genetic diversity influencing stochastic variation in the plant metabolome, defense chemistry, and growth. This genetic diversity included loci specific for the stochastic variation of each phenotypic class that did not affect the other phenotypic classes or the average phenotype. This suggests that the organism's networks are established so that noise can exist in one phenotypic level like metabolism and not permeate up or down to different phenotypic levels. Further, the genomic variation within the plastid and mitochondria also had significant effects on the stochastic variation of all phenotypic classes. The genetic influence over stochastic variation within the metabolome was highly metabolite specific, with neighboring metabolites in the same metabolic pathway frequently showing different levels of noise. As expected from bet-hedging theory, there was more genetic diversity and a wider range of stochastic variation for defense chemistry than found for primary metabolism. Thus, it is possible to begin dissecting the stochastic variation of whole organismal phenotypes in multi-cellular organisms. Further, there are loci that modulate stochastic variation at different phenotypic levels. Finding the identity of these genes will be key to developing complete models linking genotype to phenotype. PMID:25569687

Genetic variation in the nuclear and organellar genomes modulates stochastic variation in the metabolome, growth, and defense.

PubMed

Joseph, Bindu; Corwin, Jason A; Kliebenstein, Daniel J

2015-01-01

Recent studies are starting to show that genetic control over stochastic variation is a key evolutionary solution of single celled organisms in the face of unpredictable environments. This has been expanded to show that genetic variation can alter stochastic variation in transcriptional processes within multi-cellular eukaryotes. However, little is known about how genetic diversity can control stochastic variation within more non-cell autonomous phenotypes. Using an Arabidopsis reciprocal RIL population, we showed that there is significant genetic diversity influencing stochastic variation in the plant metabolome, defense chemistry, and growth. This genetic diversity included loci specific for the stochastic variation of each phenotypic class that did not affect the other phenotypic classes or the average phenotype. This suggests that the organism's networks are established so that noise can exist in one phenotypic level like metabolism and not permeate up or down to different phenotypic levels. Further, the genomic variation within the plastid and mitochondria also had significant effects on the stochastic variation of all phenotypic classes. The genetic influence over stochastic variation within the metabolome was highly metabolite specific, with neighboring metabolites in the same metabolic pathway frequently showing different levels of noise. As expected from bet-hedging theory, there was more genetic diversity and a wider range of stochastic variation for defense chemistry than found for primary metabolism. Thus, it is possible to begin dissecting the stochastic variation of whole organismal phenotypes in multi-cellular organisms. Further, there are loci that modulate stochastic variation at different phenotypic levels. Finding the identity of these genes will be key to developing complete models linking genotype to phenotype.

Schizophrenia and season of birth: relationship to geomagnetic storms.

PubMed

Kay, Ronald W

2004-01-01

An excess pattern of winter and spring birth, of those later diagnosed as schizophrenic, has been clearly identified in most Northern Hemisphere samples with none or lesser variation in Equatorial or Southern Hemisphere samples. Pregnancy and birth complications, seasonal variations in light, weather, temperature, nutrition, toxins, body chemistry and gene expression have all been hypothesized as possible causes. In this study, the hypothesis was tested that seasonal variation in the geomagnetic field of the earth primarily as a result of geomagnetic storms (GMS) at crucial periods in intrauterine brain development, during months 2 to 7 of gestation could affect the later rate of development of schizophrenia. The biological plausibility of this hypothesis is also briefly reviewed. A sample of eight representative published studies of schizophrenic monthly birth variation were compared with averaged geomagnetic disturbance using two global indices (AA*) and (aa). Three samples showed a significant negative correlation to both geomagnetic indices, a further three a significant negative correlation to one of the geomagnetic indices, one showed no significant correlation to either index and one showed a significant positive correlation to one index. It is suggested that these findings are all consistent with the hypothesis and that geomagnetic disturbance or factors associated with this disturbance should be further investigated in birth seasonality studies.

Genetic and Epigenetic Variations Induced by Wheat-Rye 2R and 5R Monosomic Addition Lines

PubMed Central

Fu, Shulan; Sun, Chuanfei; Yang, Manyu; Fei, Yunyan; Tan, Feiqun; Yan, Benju; Ren, Zhenglong; Tang, Zongxiang

2013-01-01

Background Monosomic alien addition lines (MAALs) can easily induce structural variation of chromosomes and have been used in crop breeding; however, it is unclear whether MAALs will induce drastic genetic and epigenetic alterations. Methodology/Principal Findings In the present study, wheat-rye 2R and 5R MAALs together with their selfed progeny and parental common wheat were investigated through amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP) analyses. The MAALs in different generations displayed different genetic variations. Some progeny that only contained 42 wheat chromosomes showed great genetic/epigenetic alterations. Cryptic rye chromatin has introgressed into the wheat genome. However, one of the progeny that contained cryptic rye chromatin did not display outstanding genetic/epigenetic variation. 78 and 49 sequences were cloned from changed AFLP and MSAP bands, respectively. Blastn search indicated that almost half of them showed no significant similarity to known sequences. Retrotransposons were mainly involved in genetic and epigenetic variations. Genetic variations basically affected Gypsy-like retrotransposons, whereas epigenetic alterations affected Copia-like and Gypsy-like retrotransposons equally. Genetic and epigenetic variations seldom affected low-copy coding DNA sequences. Conclusions/Significance The results in the present study provided direct evidence to illustrate that monosomic wheat-rye addition lines could induce different and drastic genetic/epigenetic variations and these variations might not be caused by introgression of rye chromatins into wheat. Therefore, MAALs may be directly used as an effective means to broaden the genetic diversity of common wheat. PMID:23342073

Non-codingRNA sequence variations in human chronic lymphocytic leukemia and colorectal cancer.

PubMed

Wojcik, Sylwia E; Rossi, Simona; Shimizu, Masayoshi; Nicoloso, Milena S; Cimmino, Amelia; Alder, Hansjuerg; Herlea, Vlad; Rassenti, Laura Z; Rai, Kanti R; Kipps, Thomas J; Keating, Michael J; Croce, Carlo M; Calin, George A

2010-02-01

Cancer is a genetic disease in which the interplay between alterations in protein-coding genes and non-coding RNAs (ncRNAs) plays a fundamental role. In recent years, the full coding component of the human genome was sequenced in various cancers, whereas such attempts related to ncRNAs are still fragmentary. We screened genomic DNAs for sequence variations in 148 microRNAs (miRNAs) and ultraconserved regions (UCRs) loci in patients with chronic lymphocytic leukemia (CLL) or colorectal cancer (CRC) by Sanger technique and further tried to elucidate the functional consequences of some of these variations. We found sequence variations in miRNAs in both sporadic and familial CLL cases, mutations of UCRs in CLLs and CRCs and, in certain instances, detected functional effects of these variations. Furthermore, by integrating our data with previously published data on miRNA sequence variations, we have created a catalog of DNA sequence variations in miRNAs/ultraconserved genes in human cancers. These findings argue that ncRNAs are targeted by both germ line and somatic mutations as well as by single-nucleotide polymorphisms with functional significance for human tumorigenesis. Sequence variations in ncRNA loci are frequent and some have functional and biological significance. Such information can be exploited to further investigate on a genome-wide scale the frequency of genetic variations in ncRNAs and their functional meaning, as well as for the development of new diagnostic and prognostic markers for leukemias and carcinomas.

Non-codingRNA sequence variations in human chronic lymphocytic leukemia and colorectal cancer

PubMed Central

Wojcik, Sylwia E.; Rossi, Simona; Shimizu, Masayoshi; Nicoloso, Milena S.; Cimmino, Amelia; Alder, Hansjuerg; Herlea, Vlad; Rassenti, Laura Z.; Rai, Kanti R.; Kipps, Thomas J.; Keating, Michael J.

2010-01-01

Cancer is a genetic disease in which the interplay between alterations in protein-coding genes and non-coding RNAs (ncRNAs) plays a fundamental role. In recent years, the full coding component of the human genome was sequenced in various cancers, whereas such attempts related to ncRNAs are still fragmentary. We screened genomic DNAs for sequence variations in 148 microRNAs (miRNAs) and ultraconserved regions (UCRs) loci in patients with chronic lymphocytic leukemia (CLL) or colorectal cancer (CRC) by Sanger technique and further tried to elucidate the functional consequences of some of these variations. We found sequence variations in miRNAs in both sporadic and familial CLL cases, mutations of UCRs in CLLs and CRCs and, in certain instances, detected functional effects of these variations. Furthermore, by integrating our data with previously published data on miRNA sequence variations, we have created a catalog of DNA sequence variations in miRNAs/ultraconserved genes in human cancers. These findings argue that ncRNAs are targeted by both germ line and somatic mutations as well as by single-nucleotide polymorphisms with functional significance for human tumorigenesis. Sequence variations in ncRNA loci are frequent and some have functional and biological significance. Such information can be exploited to further investigate on a genome-wide scale the frequency of genetic variations in ncRNAs and their functional meaning, as well as for the development of new diagnostic and prognostic markers for leukemias and carcinomas. PMID:19926640

Chimpanzee sociability is associated with vasopressin (Avpr1a) but not oxytocin receptor gene (OXTR) variation.

PubMed

Staes, Nicky; Koski, Sonja E; Helsen, Philippe; Fransen, Erik; Eens, Marcel; Stevens, Jeroen M G

2015-09-01

The importance of genes in regulating phenotypic variation of personality traits in humans and animals is becoming increasingly apparent in recent studies. Here we focus on variation in the vasopressin receptor gene 1a (Avpr1a) and oxytocin receptor gene (OXTR) and their effects on social personality traits in chimpanzees. We combine newly available genetic data on Avpr1a and OXTR allelic variation of 62 captive chimpanzees with individual variation in personality, based on behavioral assessments. Our study provides support for the positive association of the Avpr1a promoter region, in particular the presence of DupB, and sociability in chimpanzees. This complements findings of previous studies on adolescent chimpanzees and studies that assessed personality using questionnaire data. In contrast, no significant associations were found for the single nucleotide polymorphism (SNP) ss1388116472 of the OXTR and any of the personality components. Most importantly, our study provides additional evidence for the regulatory function of the 5' promoter region of Avpr1a on social behavior and its evolutionary stable effect across species, including rodents, chimpanzees and humans. Although it is generally accepted that complex social behavior is regulated by a combination of genes, the environment and their interaction, our findings highlight the importance of candidate genes with large effects on behavioral variation. Copyright © 2015 Elsevier Inc. All rights reserved.

Random matrix approach to the dynamics of stock inventory variations

NASA Astrophysics Data System (ADS)

Zhou, Wei-Xing; Mu, Guo-Hua; Kertész, János

2012-09-01

It is well accepted that investors can be classified into groups owing to distinct trading strategies, which forms the basic assumption of many agent-based models for financial markets when agents are not zero-intelligent. However, empirical tests of these assumptions are still very rare due to the lack of order flow data. Here we adopt the order flow data of Chinese stocks to tackle this problem by investigating the dynamics of inventory variations for individual and institutional investors that contain rich information about the trading behavior of investors and have a crucial influence on price fluctuations. We find that the distributions of cross-correlation coefficient Cij have power-law forms in the bulk that are followed by exponential tails, and there are more positive coefficients than negative ones. In addition, it is more likely that two individuals or two institutions have a stronger inventory variation correlation than one individual and one institution. We find that the largest and the second largest eigenvalues (λ1 and λ2) of the correlation matrix cannot be explained by random matrix theory and the projections of investors' inventory variations on the first eigenvector u(λ1) are linearly correlated with stock returns, where individual investors play a dominating role. The investors are classified into three categories based on the cross-correlation coefficients CV R between inventory variations and stock returns. A strong Granger causality is unveiled from stock returns to inventory variations, which means that a large proportion of individuals hold the reversing trading strategy and a small part of individuals hold the trending strategy. Our empirical findings have scientific significance in the understanding of investors' trading behavior and in the construction of agent-based models for emerging stock markets.

Effects of gender and regional dialect on prosodic patterns in American English

PubMed Central

Clopper, Cynthia G.; Smiljanic, Rajka

2011-01-01

While cross-dialect prosodic variation has been well established for many languages, most variationist research on regional dialects of American English has focused on the vowel system. The current study was designed to explore prosodic variation in read speech in two regional varieties of American English: Southern and Midland. Prosodic dialect variation was analyzed in two domains: speaking rate and the phonetic expression of pitch movements associated with accented and phrase-final syllables. The results revealed significant effects of regional dialect on the distributions of pauses, pitch accents, and phrasal-boundary tone combinations. Significant effects of talker gender were also observed on the distributions of pitch accents and phrasal-boundary tone combinations. The findings from this study demonstrate that regional and gender identity features are encoded in part through prosody, and provide further motivation for the close examination of prosodic patterns across regional and social varieties of American English. PMID:21686317

Regional variation in smoking among African Americans.

PubMed

King, G; Polednak, A P; Bendel, R

1999-08-01

The impact of geographic region and metropolitan residence on smoking prevalence among African Americans has not been adequately examined. This study analyzed 5 years of data from the National Health Interview Survey (1990-1994) on current smoking and regional variation among 16,738 African Americans. Results. Respondents in the West had the lowest unadjusted smoking prevalence rates and Midwest residents had the highest. Current smoking was lower among African Americans living in non-central cities than in central cities even after adjusting for several sociodemographic covariates. Multivariate logistic regression analysis revealed that black women in the South were significantly less likely to be smokers compared with any other gender/region group. These findings suggest the significance of gender and regional factors such as the social history of migration, social stress and racism, exposure to tobacco advertisement, variations in cultural influences, community structures, and coping strategies in under standing African American smoking behavior. Copyright 1999 American Health Foundation and Academic Press.

Brightness Variations in the Solar Atmosphere as Seen by SOHO

NASA Astrophysics Data System (ADS)

Brkovic, A.; Rüedi, I.; Solanki, S. K.; Huber, M. C. E.; Stenflo, J. O.; Stucki, K.; Harrison, R.; Fludra, A.

We present preliminary results of a statistical analysis of the brightness variations of solar features at different levels in the solar atmosphere. We observed quiet Sun regions at disc centre using the Coronal Diagnostic Spectrometer (CDS) onboard the Solar and Heliospheric Observatory (SOHO). We find significant variability at all time scales in all parts of the quiet Sun, from darkest intranetwork to brightest network. Such variations are observed simultaneously in the chromospheric He I 584.33 Angstroms (2 \\cdot 10^4 K) line, the transition region O V 629.74 Angstroms (2.5 \\cdot 10^5 K) and coronal Mg IX 368.06 Angstroms (10^6 K) line. The relative variability is independent of brightness and most of the variability appears to take place on time scales longer than 5 minutes for all 3 spectral lines. No significant differences are observed between the different data sets.

Environmental Effects on Affect: Density, Noise and Personality.

ERIC Educational Resources Information Center

Bharucha-Reid, Rodabe; Kivak, H. Asuman

1982-01-01

Research findings are reported of a study (N=88 undergraduate males) of molar crowding in urban centers which involved the simultaneous variation of social density, spatial density, noise, and personality as they effect room affect (physical and psychological). Several main effects proved significant. (Author/DC)

Lack of association between temporal lobe epilepsy and a novel polymorphism in the alpha 2 subunit gene (ATP1A2) of the sodium potassium transporting ATPase.

PubMed

Buono, R J; Ferraro, T N; O'Connor, M J; Sperling, M R; Abbey, M; Finanger, E; Lohoff, F; Mulholland, N; Berrettini, W H

2000-02-07

Genetic linkage studies in rodents and humans have identified specific chromosomal regions harboring seizure susceptibility genes. We have identified a novel polymorphism in the human alpha 2 subunit gene (ATP1A2) of the sodium potassium transporting ATPase (NaK-pump), a candidate gene for human temporal lobe epilepsy (TLE) based on its chromosomal location and function in ion homeostasis. The polymorphism consists of a four base pair insertion 12 base pairs upstream of the start of exon 2. We performed an association study between this polymorphism and TLE. Our study did not find a significant difference in the frequency of this polymorphism between TLE patients and controls, indicating that this variation is not a major susceptibility factor. However, since the number of patients studied so far is small and the functional consequence of the polymorphism is unknown, the variation may yet be found to play a minor role in increased risk for seizure susceptibility. In contrast to the findings in TLE patients and controls, we did find a significant difference in the frequency of the variation between African Americans and persons of European descent. This finding demonstrates the potential effect of population stratification on studies of this type and supports the growing use of parental and familial samples for controls in association studies. Further study of this polymorphism is warranted as it may be involved in other disease processes for which there are known ethnic-specific susceptibilities. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:79-83, 2000. Copyright 2000 Wiley-Liss, Inc.

Soil respiration across a permafrost transition zone: spatial structure and environmental correlates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stegen, James C.; Anderson, Carolyn G.; Bond-Lamberty, Ben

Soil respiration is a key ecosystem function whereby shifts in respiration rates can shift systems from carbon sinks to sources. Soil respiration in permafrost-associated systems is particularly important given climate change driven permafrost thaw that leads to significant uncertainty in resulting ecosystem carbon dynamics. Here we characterize the spatial structure and environmental drivers of soil respiration across a permafrost transition zone. We find that soil respiration is characterized by a non-linear threshold that occurs at active-layer depths greater than 140 cm. We also find that within each season, tree basal area is a dominant driver of soil respiration regardless of spatial scale, but onlymore » in spatial domains with significant spatial variability in basal area. Our analyses further show that spatial variation (the coefficient of variation) and mean-variance power-law scaling of soil respiration in our boreal system are consistent with previous work in other ecosystems (e.g., tropical forests) and in population ecology, respectively. Comparing our results to those in other ecosystems suggests that temporally stable features such as tree-stand structure are often primary drivers of spatial variation in soil respiration. If so, this provides an opportunity to better estimate the magnitude and spatial variation in soil respiration through remote sensing. Finally, combining such an approach with broader knowledge of thresholding behavior – here related to active layer depth – would provide empirical constraints on models aimed at predicting ecosystem responses to ongoing permafrost thaw.« less

Soil respiration across a permafrost transition zone: spatial structure and environmental correlates

DOE PAGES

Stegen, James C.; Anderson, Carolyn G.; Bond-Lamberty, Ben; ...

2017-09-28

Soil respiration is a key ecosystem function whereby shifts in respiration rates can shift systems from carbon sinks to sources. Soil respiration in permafrost-associated systems is particularly important given climate change driven permafrost thaw that leads to significant uncertainty in resulting ecosystem carbon dynamics. Here we characterize the spatial structure and environmental drivers of soil respiration across a permafrost transition zone. We find that soil respiration is characterized by a non-linear threshold that occurs at active-layer depths greater than 140 cm. We also find that within each season, tree basal area is a dominant driver of soil respiration regardless of spatial scale, but onlymore » in spatial domains with significant spatial variability in basal area. Our analyses further show that spatial variation (the coefficient of variation) and mean-variance power-law scaling of soil respiration in our boreal system are consistent with previous work in other ecosystems (e.g., tropical forests) and in population ecology, respectively. Comparing our results to those in other ecosystems suggests that temporally stable features such as tree-stand structure are often primary drivers of spatial variation in soil respiration. If so, this provides an opportunity to better estimate the magnitude and spatial variation in soil respiration through remote sensing. Finally, combining such an approach with broader knowledge of thresholding behavior – here related to active layer depth – would provide empirical constraints on models aimed at predicting ecosystem responses to ongoing permafrost thaw.« less

Nonlinear permanent migration response to climatic variations but minimal response to disasters

PubMed Central

Bohra-Mishra, Pratikshya; Oppenheimer, Michael; Hsiang, Solomon M.

2014-01-01

We present a microlevel study to simultaneously investigate the effects of variations in temperature and precipitation along with sudden natural disasters to infer their relative influence on migration that is likely permanent. The study is made possible by the availability of household panel data from Indonesia with an exceptional tracking rate combined with frequent occurrence of natural disasters and significant climatic variations, thus providing a quasi-experiment to examine the influence of environment on migration. Using data on 7,185 households followed over 15 y, we analyze whole-household, province-to-province migration, which allows us to understand the effects of environmental factors on permanent moves that may differ from temporary migration. The results suggest that permanent migration is influenced by climatic variations, whereas episodic disasters tend to have much smaller or no impact on such migration. In particular, temperature has a nonlinear effect on migration such that above 25 °C, a rise in temperature is related to an increase in outmigration, potentially through its impact on economic conditions. We use these results to estimate the impact of projected temperature increases on future permanent migration. Though precipitation also has a similar nonlinear effect on migration, the effect is smaller than that of temperature, underscoring the importance of using an expanded set of climatic factors as predictors of migration. These findings on the minimal influence of natural disasters and precipitation on permanent moves supplement previous findings on the significant role of these variables in promoting temporary migration. PMID:24958887

Soil respiration across a permafrost transition zone: spatial structure and environmental correlates

NASA Astrophysics Data System (ADS)

Stegen, James C.; Anderson, Carolyn G.; Bond-Lamberty, Ben; Crump, Alex R.; Chen, Xingyuan; Hess, Nancy

2017-09-01

Soil respiration is a key ecosystem function whereby shifts in respiration rates can shift systems from carbon sinks to sources. Soil respiration in permafrost-associated systems is particularly important given climate change driven permafrost thaw that leads to significant uncertainty in resulting ecosystem carbon dynamics. Here we characterize the spatial structure and environmental drivers of soil respiration across a permafrost transition zone. We find that soil respiration is characterized by a non-linear threshold that occurs at active-layer depths greater than 140 cm. We also find that within each season, tree basal area is a dominant driver of soil respiration regardless of spatial scale, but only in spatial domains with significant spatial variability in basal area. Our analyses further show that spatial variation (the coefficient of variation) and mean-variance power-law scaling of soil respiration in our boreal system are consistent with previous work in other ecosystems (e.g., tropical forests) and in population ecology, respectively. Comparing our results to those in other ecosystems suggests that temporally stable features such as tree-stand structure are often primary drivers of spatial variation in soil respiration. If so, this provides an opportunity to better estimate the magnitude and spatial variation in soil respiration through remote sensing. Combining such an approach with broader knowledge of thresholding behavior - here related to active layer depth - would provide empirical constraints on models aimed at predicting ecosystem responses to ongoing permafrost thaw.

Nonlinear permanent migration response to climatic variations but minimal response to disasters.

PubMed

Bohra-Mishra, Pratikshya; Oppenheimer, Michael; Hsiang, Solomon M

2014-07-08

We present a microlevel study to simultaneously investigate the effects of variations in temperature and precipitation along with sudden natural disasters to infer their relative influence on migration that is likely permanent. The study is made possible by the availability of household panel data from Indonesia with an exceptional tracking rate combined with frequent occurrence of natural disasters and significant climatic variations, thus providing a quasi-experiment to examine the influence of environment on migration. Using data on 7,185 households followed over 15 y, we analyze whole-household, province-to-province migration, which allows us to understand the effects of environmental factors on permanent moves that may differ from temporary migration. The results suggest that permanent migration is influenced by climatic variations, whereas episodic disasters tend to have much smaller or no impact on such migration. In particular, temperature has a nonlinear effect on migration such that above 25 °C, a rise in temperature is related to an increase in outmigration, potentially through its impact on economic conditions. We use these results to estimate the impact of projected temperature increases on future permanent migration. Though precipitation also has a similar nonlinear effect on migration, the effect is smaller than that of temperature, underscoring the importance of using an expanded set of climatic factors as predictors of migration. These findings on the minimal influence of natural disasters and precipitation on permanent moves supplement previous findings on the significant role of these variables in promoting temporary migration.

Genetic variation in adaptability and pleiotropy in budding yeast

PubMed Central

Mitchell, James Kameron; Bloom, Joshua S; Kruglyak, Leonid

2017-01-01

Evolution can favor organisms that are more adaptable, provided that genetic variation in adaptability exists. Here, we quantify this variation among 230 offspring of a cross between diverged yeast strains. We measure the adaptability of each offspring genotype, defined as its average rate of adaptation in a specific environmental condition, and analyze the heritability, predictability, and genetic basis of this trait. We find that initial genotype strongly affects adaptability and can alter the genetic basis of future evolution. Initial genotype also affects the pleiotropic consequences of adaptation for fitness in a different environment. This genetic variation in adaptability and pleiotropy is largely determined by initial fitness, according to a rule of declining adaptability with increasing initial fitness, but several individual QTLs also have a significant idiosyncratic role. Our results demonstrate that both adaptability and pleiotropy are complex traits, with extensive heritable differences arising from naturally occurring variation. PMID:28826486

Predictions of avian Plasmodium expansion under climate change.

PubMed

Loiseau, Claire; Harrigan, Ryan J; Bichet, Coraline; Julliard, Romain; Garnier, Stéphane; Lendvai, Adám Z; Chastel, Olivier; Sorci, Gabriele

2013-01-01

Vector-borne diseases are particularly responsive to changing environmental conditions. Diurnal temperature variation has been identified as a particularly important factor for the development of malaria parasites within vectors. Here, we conducted a survey across France, screening populations of the house sparrow (Passer domesticus) for malaria (Plasmodium relictum). We investigated whether variation in remotely-sensed environmental variables accounted for the spatial variation observed in prevalence and parasitemia. While prevalence was highly correlated to diurnal temperature range and other measures of temperature variation, environmental conditions could not predict spatial variation in parasitemia. Based on our empirical data, we mapped malaria distribution under climate change scenarios and predicted that Plasmodium occurrence will spread to regions in northern France, and that prevalence levels are likely to increase in locations where transmission already occurs. Our findings, based on remote sensing tools coupled with empirical data suggest that climatic change will significantly alter transmission of malaria parasites.

Genetic variation in adaptability and pleiotropy in budding yeast.

PubMed

Jerison, Elizabeth R; Kryazhimskiy, Sergey; Mitchell, James Kameron; Bloom, Joshua S; Kruglyak, Leonid; Desai, Michael M

2017-08-17

Evolution can favor organisms that are more adaptable, provided that genetic variation in adaptability exists. Here, we quantify this variation among 230 offspring of a cross between diverged yeast strains. We measure the adaptability of each offspring genotype, defined as its average rate of adaptation in a specific environmental condition, and analyze the heritability, predictability, and genetic basis of this trait. We find that initial genotype strongly affects adaptability and can alter the genetic basis of future evolution. Initial genotype also affects the pleiotropic consequences of adaptation for fitness in a different environment. This genetic variation in adaptability and pleiotropy is largely determined by initial fitness, according to a rule of declining adaptability with increasing initial fitness, but several individual QTLs also have a significant idiosyncratic role. Our results demonstrate that both adaptability and pleiotropy are complex traits, with extensive heritable differences arising from naturally occurring variation.

The Genetic Basis of Natural Variation in Caenorhabditis elegans Telomere Length

PubMed Central

Cook, Daniel E.; Zdraljevic, Stefan; Tanny, Robyn E.; Seo, Beomseok; Riccardi, David D.; Noble, Luke M.; Rockman, Matthew V.; Alkema, Mark J.; Braendle, Christian; Kammenga, Jan E.; Wang, John; Kruglyak, Leonid; Félix, Marie-Anne; Lee, Junho; Andersen, Erik C.

2016-01-01

Telomeres are involved in the maintenance of chromosomes and the prevention of genome instability. Despite this central importance, significant variation in telomere length has been observed in a variety of organisms. The genetic determinants of telomere-length variation and their effects on organismal fitness are largely unexplored. Here, we describe natural variation in telomere length across the Caenorhabditis elegans species. We identify a large-effect variant that contributes to differences in telomere length. The variant alters the conserved oligonucleotide/oligosaccharide-binding fold of protection of telomeres 2 (POT-2), a homolog of a human telomere-capping shelterin complex subunit. Mutations within this domain likely reduce the ability of POT-2 to bind telomeric DNA, thereby increasing telomere length. We find that telomere-length variation does not correlate with offspring production or longevity in C. elegans wild isolates, suggesting that naturally long telomeres play a limited role in modifying fitness phenotypes in C. elegans. PMID:27449056

Family-based association study of matrix metalloproteinase-3 and -9 haplotypes with susceptibility to ischemic white matter injury.

PubMed

Fornage, Myriam; Mosley, Thomas H; Jack, Clifford R; de Andrade, Mariza; Kardia, Sharon L R; Boerwinkle, Eric; Turner, Stephen T

2007-01-01

Susceptibility to ischemic damage to the subcortical white matter of the brain has a strong genetic basis. Dysregulation of matrix metalloproteinases (MMPs) contributes to loss of cerebrovascular integrity and white matter injury. We investigated whether sequence variation in the genes encoding MMP3 and MMP9 is associated with variation in leukoaraiosis volume, determined by magnetic resonance imaging, in non-Hispanic whites and African-Americans using family-based association tests. Seven hundred and fifty-six white and 671 African-American individuals from sibships ascertained through two or more siblings with hypertension were genotyped for 7 and 8 haplotype-tagging polymorphisms in the MMP3 and MMP9 genes, respectively. MMP3 sequence variation was significantly associated with variation in leukoaraiosis volume in Whites. Two common haplotypes with opposing relationships to leukoaraiosis volume were identified. MMP9 sequence variation was also significantly associated with variation in leukoaraiosis volume in both African-Americans and Whites. Different haplotypes contributed to these associations in the two racial groups. These findings add to the growing body of evidence from animal models and human clinical studies suggesting a role of MMPs in ischemic white matter injury. They provide the basis for further investigation of the role of these genes in susceptibility and/or progression to clinical disease.

Evidence of Dynamic Crustal Deformation in Tohoku, Japan, From Time-Varying Receiver Functions

NASA Astrophysics Data System (ADS)

Porritt, R. W.; Yoshioka, S.

2017-10-01

Temporal variation of crustal structure is key to our understanding of Earth processes on human timescales. Often, we expect that the most significant structural variations are caused by strong ground shaking associated with large earthquakes, and recent studies seem to confirm this. Here we test the possibility of using P receiver functions (PRF) to isolate structural variations over time. Synthetic receiver function tests indicate that structural variation could produce PRF changes on the same order of magnitude as random noise or contamination by local earthquakes. Nonetheless, we find significant variability in observed receiver functions over time at several stations located in northeastern Honshu. Immediately following the Tohoku-oki earthquake, we observe high PRF variation clustering spatially, especially in two regions near the beginning and end of the rupture plane. Due to the depth sensitivity of PRF and the timescales over which this variability is observed, we infer this effect is primarily due to fluid migration in volcanic regions and shear stress/strength reorganization. While the noise levels in PRF are high for this type of analysis, by sampling small data sets, the computational cost is lower than other methods, such as ambient noise, thereby making PRF a useful tool for estimating temporal variations in crustal structure.

Immunogenetic Variation and Differential Pathogen Exposure in Free-Ranging Cheetahs across Namibian Farmlands

PubMed Central

Castro-Prieto, Aines; Wachter, Bettina; Melzheimer, Joerg; Thalwitzer, Susanne; Hofer, Heribert; Sommer, Simone

2012-01-01

Background Genes under selection provide ecologically important information useful for conservation issues. Major histocompatibility complex (MHC) class I and II genes are essential for the immune defence against pathogens from intracellular (e.g. viruses) and extracellular (e.g. helminths) origins, respectively. Serosurvey studies in Namibian cheetahs (Acinonyx juabuts) revealed higher exposure to viral pathogens in individuals from north-central than east-central regions. Here we examined whether the observed differences in exposure to viruses influence the patterns of genetic variation and differentiation at MHC loci in 88 free-ranging Namibian cheetahs. Methodology/Principal Findings Genetic variation at MHC I and II loci was assessed through single-stranded conformation polymorphism (SSCP) analysis and sequencing. While the overall allelic diversity did not differ, we observed a high genetic differentiation at MHC class I loci between cheetahs from north-central and east-central Namibia. No such differentiation in MHC class II and neutral markers were found. Conclusions/Significance Our results suggest that MHC class I variation mirrors the variation in selection pressure imposed by viruses in free-ranging cheetahs across Namibian farmland. This is of high significance for future management and conservation programs of this species. PMID:23145096

Association between VDR and ESR1 gene polymorphisms with bone and obesity phenotypes in Chinese male nuclear families.

PubMed

Gu, Jie-mei; Xiao, Wen-jin; He, Jin-wei; Zhang, Hao; Hu, Wei-wei; Hu, Yun-qiu; Li, Miao; Liu, Yu-juan; Fu, Wen-zhen; Yu, Jin-bo; Gao, Gao; Yue, Hua; Ke, Yao-hua; Zhang, Zhen-lin

2009-12-01

The goal of this study was to determine whether polymorphisms in the vitamin D receptor (VDR) and estrogen receptor alpha (ESR1) genes are associated with variations of peak bone mineral density (BMD) and obesity phenotypes in young Chinese men. A total of 1215 subjects from 400 Chinese nuclear families were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele-specific multiple PCR (ASM-PCR) analysis at the ApaI, FokI, and CDX2 sites in the VDR gene and the PvuII and XbaI sites in the ESR1 gene. BMD at the lumbar spine and hip, total fat mass, and total lean mass were measured using dual energy X-ray absorptiometry. The associations between VDR and ESR1 gene polymorphisms with peak BMD, body mass index (BMI), total fat mass, total lean mass, and percentage fat mass (PFM) were determined using quantitative transmission disequilibrium tests (QTDTs). Using QTDTs, no significant within-family associations were obtained between genotypes or haplotypes of the VDR and ESR1 genes and peak BMD. For the obesity phenotypes, the within-family associations were significant between CDX2 genotypes and BMI (P=0.046), fat mass (P=0.004), and PFM (P=0.020). Further, PvuII was significantly associated with the variation of fat mass and PFM (P=0.002 and P=0.039, respectively). A subsequent 1000 permutations were in agreement with these within-family association results. Our findings showed that VDR and ESR1 polymorphisms were associated with total fat mass in young Chinese men, but we failed to find a significant association between VDR and ESR1 genotypes and peak BMD. These findings suggested that the VDR and ESR1 genes are quantitative trait loci (QTL) underlying fat mass variation in young Chinese men.

Bacterial and fungal communities and contribution of physicochemical factors during cattle farm waste composting.

PubMed

Huhe; Jiang, Chao; Wu, Yanpei; Cheng, Yunxiang

2017-12-01

During composting, the composition of microbial communities is subject to constant change owing to interactions with fluctuating physicochemical parameters. This study explored the changes in bacterial and fungal communities during cattle farm waste composting and aimed to identify and prioritize the contributing physicochemical factors. Microbial community compositions were determined by high-throughput sequencing. While the predominant phyla in the bacterial and fungal communities were largely consistent during the composting, differences in relative abundances were observed. Bacterial and fungal community diversity and relative abundance varied significantly, and inversely, over time. Relationships between physicochemical factors and microbial community compositions were evaluated by redundancy analysis. The variation in bacterial community composition was significantly related to water-soluble organic carbon (WSOC), and pile temperature and moisture (p < .05), while the largest portions of variation in fungal community composition were explained by pile temperature, WSOC, and C/N (p < .05). These findings indicated that those parameters are the most likely ones to influence, or be influenced by the bacterial and fungal communities. Variation partitioning analyses indicated that WSOC and pile temperature had predominant effects on bacterial and fungal community composition, respectively. Our findings will be useful for improving the quality of cattle farm waste composts. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

VARIATIONS IN SOLAR WIND FRACTIONATION AS SEEN BY ACE/SWICS AND THE IMPLICATIONS FOR GENESIS MISSION RESULTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pilleri, P.; Wiens, R. C.; Reisenfeld, D. B.

We use Advanced Composition Explorer (ACE)/Solar Wind Ion Composition Spectrometer (SWICS) elemental composition data to compare the variations in solar wind (SW) fractionation as measured by SWICS during the last solar maximum (1999–2001), the solar minimum (2006–2009), and the period in which the Genesis spacecraft was collecting SW (late 2001—early 2004). We differentiate our analysis in terms of SW regimes (i.e., originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-first ionization potential (low-FIP) ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that relative tomore » magnesium, the other low-FIP elements are measurably fractionated, but the degree of fractionation does not vary significantly over the solar cycle. For the high-FIP ions, variation in fractionation over the solar cycle is significant: greatest for Ne/Mg and C/Mg, less so for O/Mg, and the least for He/Mg. When abundance ratios are examined as a function of SW speed, we find a strong correlation, with the remarkable observation that the degree of fractionation follows a mass-dependent trend. We discuss the implications for correcting the Genesis sample return results to photospheric abundances.« less

Modelling level, trend and geographical variations in stigma and discrimination against people living with HIV/AIDS in Nigeria.

PubMed

Adebayo, Samson B; Fakolade, Richard; Anyanti, Jennifer; Ekweremadu, Bright; Ladipo, Olaronke; Ankomah, Augustine

2011-01-01

People living with HIV and AIDS (PLHA) often face stigma and discrimination. Stigma is a powerful tool for social control and PLHA are to varying degrees stigmatised against. Consequences of stigma and discrimination against PLHA may result in low turn-out for HIV counselling and testing, identity crises, isolation, loneliness, low self-esteem and lack of interest in containing the disease. To achieve the millennium development goal on HIV reduction, efforts should be targeted at measuring impact of HIV preventive interventions. In this paper, effort was made to explore geographical variations in addition to level and trend of accepting attitude towards PLHA using 2003 - 2007 population-based household survey data. Inferences are based on Markov Chain Monte Carlo techniques, while model selection was based on Deviance Information Criteria. Findings revealed significant positive trend and spatial variations on level of accepting attitude towards PLHA. Level of exposure to HIV prevention interventions and perceptions about social support received on HIV are significantly associated with accepting attitude towards PLHA. Findings provide policy makers with tools to discern states where prevention efforts on HIV-related stigma and discrimination should be intensified. This in turn, can enhance an effective utilization of scarce resources that is paramount in developing countries.

Partial diel migration: A facultative migration underpinned by long-term inter-individual variation.

PubMed

Harrison, Philip M; Gutowsky, Lee F G; Martins, Eduardo G; Patterson, David A; Cooke, Steven J; Power, Michael

2017-09-01

The variations in migration that comprise partial diel migrations, putatively occur entirely as a consequence of behavioural flexibility. However, seasonal partial migrations are increasingly recognised to be mediated by a combination of reversible plasticity in response to environmental variation and individual variation due to genetic and environmental effects. Here, we test the hypothesis that while partial diel migration heterogeneity occurs primarily due to short-term within-individual flexibility in behaviour, long-term individual differences in migratory behaviour also underpin this migration variation. Specifically, we use a hierarchical behavioural reaction norm approach to partition within- and among-individual variation in depth use and diel plasticity in depth use, across short- and long-term time-scales, in a group of 47 burbot (Lota lota) tagged with depth-sensing acoustic telemetry transmitters. We found that within-individual variation at the among-dates-within-seasons and among-seasons scale, explained the dominant proportion of phenotypic variation. However, individuals also repeatedly differed in their expression of migration behaviour over the 2 year study duration. These results reveal that diel migration variation occurs primarily due to short-term within-individual flexibility in depth use and diel migration behaviour. However, repeatable individual differences also played a key role in mediating partial diel migration. These findings represent a significant advancement of our understanding of the mechanisms generating the important, yet poorly understood phenomena of partial diel migration. Moreover, given the pervasive occurrence of diel migrations across aquatic taxa, these findings indicate that individual differences have an important, yet previously unacknowledged role in structuring the temporal and vertical dynamics of aquatic ecosystems. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Annual variation in the atmospheric radon concentration in Japan.

PubMed

Kobayashi, Yuka; Yasuoka, Yumi; Omori, Yasutaka; Nagahama, Hiroyuki; Sanada, Tetsuya; Muto, Jun; Suzuki, Toshiyuki; Homma, Yoshimi; Ihara, Hayato; Kubota, Kazuhito; Mukai, Takahiro

2015-08-01

Anomalous atmospheric variations in radon related to earthquakes have been observed in hourly exhaust-monitoring data from radioisotope institutes in Japan. The extraction of seismic anomalous radon variations would be greatly aided by understanding the normal pattern of variation in radon concentrations. Using atmospheric daily minimum radon concentration data from five sampling sites, we show that a sinusoidal regression curve can be fitted to the data. In addition, we identify areas where the atmospheric radon variation is significantly affected by the variation in atmospheric turbulence and the onshore-offshore pattern of Asian monsoons. Furthermore, by comparing the sinusoidal regression curve for the normal annual (seasonal) variations at the five sites to the sinusoidal regression curve for a previously published dataset of radon values at the five Japanese prefectures, we can estimate the normal annual variation pattern. By fitting sinusoidal regression curves to the previously published dataset containing sites in all Japanese prefectures, we find that 72% of the Japanese prefectures satisfy the requirements of the sinusoidal regression curve pattern. Using the normal annual variation pattern of atmospheric daily minimum radon concentration data, these prefectures are suitable areas for obtaining anomalous radon variations related to earthquakes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effectiveness of bomber deployed autonomous airborne vehicles in finding rail mobile SS-24s

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abey, A.E.; Erickson, S.A.; Norquist, P.D.

1990-08-01

Computer simulation predictions of the effectiveness of autonomous airborne vehicles in finding rail mobile SS-24s are presented. Effectiveness is discussed for several autonomous airborne vehicle endurances and survivabilities for the search area southwest of Moscow. The effect of where the Soviets place the SS-24s on the rail network was also investigated. The simulation predicts significant variations in the ability of a multi-autonomous airborne vehicle system to find SS-24s with these parameters. 12 figs., 1 tab.

Adolescent Self-Reported and Peer-Reported Self-Esteem.

ERIC Educational Resources Information Center

O'Donnell, William James

1979-01-01

The study is an examination of the relationship between adolescents' self-reported and peer-reported self-esteem and how this relationship is affected by sex, race, and age variables. Significant sex and race variations interacted with age. Explanatory hypotheses for these findings are given. (Author/KC)

Student Effort, Consistency, and Online Performance

ERIC Educational Resources Information Center

Patron, Hilde; Lopez, Salvador

2011-01-01

This paper examines how student effort, consistency, motivation, and marginal learning, influence student grades in an online course. We use data from eleven Microeconomics courses taught online for a total of 212 students. Our findings show that consistency, or less time variation, is a statistically significant explanatory variable, whereas…

Shape Variation in Aterian Tanged Tools and the Origins of Projectile Technology: A Morphometric Perspective on Stone Tool Function

PubMed Central

Iovita, Radu

2011-01-01

Background Recent findings suggest that the North African Middle Stone Age technocomplex known as the Aterian is both much older than previously assumed, and certainly associated with fossils exhibiting anatomically modern human morphology and behavior. The Aterian is defined by the presence of ‘tanged’ or ‘stemmed’ tools, which have been widely assumed to be among the earliest projectile weapon tips. The present study systematically investigates morphological variation in a large sample of Aterian tools to test the hypothesis that these tools were hafted and/or used as projectile weapons. Methodology/Principal Findings Both classical morphometrics and Elliptical Fourier Analysis of tool outlines are used to show that the shape variation in the sample exhibits size-dependent patterns consistent with a reduction of the tools from the tip down, with the tang remaining intact. Additionally, the process of reduction led to increasing side-to-side asymmetries as the tools got smaller. Finally, a comparison of shape-change trajectories between Aterian tools and Late Paleolithic arrowheads from the North German site of Stellmoor reveal significant differences in terms of the amount and location of the variation. Conclusions/Significance The patterns of size-dependent shape variation strongly support the functional hypothesis of Aterian tools as hafted knives or scrapers with alternating active edges, rather than as weapon tips. Nevertheless, the same morphological patterns are interpreted as one of the earliest evidences for a hafting modification, and for the successful combination of different raw materials (haft and stone tip) into one implement, in itself an important achievement in the evolution of hominin technologies. PMID:22216161

Faecal glucocorticoid metabolites and alarm calling in free-living yellow-bellied marmots.

PubMed

Blumstein, Daniel T; Patton, Marilyn L; Saltzman, Wendy

2006-03-22

When individuals of a variety of species encounter a potential predator, some, but not all, emit alarm calls. To explain the proximate basis of this variation, we compared faecal glucocorticoid metabolite concentrations in live-trapped yellow-bellied marmots (Marmota flaviventris) between occasions when they did and did not emit alarm calls. We found that marmots had significantly higher glucocorticoid levels when they called than when they did not call, suggesting that stress or arousal may play an important role in potentiating alarm calls. Marmots are sensitive to variation in the reliability of callers. The present finding provides one possible mechanism underlying caller variation: physiological arousal influences the propensity to emit alarm calls.

Faecal glucocorticoid metabolites and alarm calling in free-living yellow-bellied marmots

PubMed Central

Blumstein, Daniel T; Patton, Marilyn L; Saltzman, Wendy

2005-01-01

When individuals of a variety of species encounter a potential predator, some, but not all, emit alarm calls. To explain the proximate basis of this variation, we compared faecal glucocorticoid metabolite concentrations in live-trapped yellow-bellied marmots (Marmota flaviventris) between occasions when they did and did not emit alarm calls. We found that marmots had significantly higher glucocorticoid levels when they called than when they did not call, suggesting that stress or arousal may play an important role in potentiating alarm calls. Marmots are sensitive to variation in the reliability of callers. The present finding provides one possible mechanism underlying caller variation: physiological arousal influences the propensity to emit alarm calls. PMID:17148318

Simulated linear test applied to quantitative proteomics.

PubMed

Pham, T V; Jimenez, C R

2016-09-01

Omics studies aim to find significant changes due to biological or functional perturbation. However, gene and protein expression profiling experiments contain inherent technical variation. In discovery proteomics studies where the number of samples is typically small, technical variation plays an important role because it contributes considerably to the observed variation. Previous methods place both technical and biological variations in tightly integrated mathematical models that are difficult to adapt for different technological platforms. Our aim is to derive a statistical framework that allows the inclusion of a wide range of technical variability. We introduce a new method called the simulated linear test, or the s-test, that is easy to implement and easy to adapt for different models of technical variation. It generates virtual data points from the observed values according to a pre-defined technical distribution and subsequently employs linear modeling for significance analysis. We demonstrate the flexibility of the proposed approach by deriving a new significance test for quantitative discovery proteomics for which missing values have been a major issue for traditional methods such as the t-test. We evaluate the result on two label-free (phospho) proteomics datasets based on ion-intensity quantitation. Available at http://www.oncoproteomics.nl/software/stest.html : t.pham@vumc.nl. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Exo-Milankovitch Cycles. I. Orbits and Rotation States

NASA Astrophysics Data System (ADS)

Deitrick, Russell; Barnes, Rory; Quinn, Thomas R.; Armstrong, John; Charnay, Benjamin; Wilhelm, Caitlyn

2018-02-01

The obliquity of the Earth, which controls our seasons, varies by only ∼2.°5 over ∼40,000 years, and its eccentricity varies by only ∼0.05 over 100,000 years. Nonetheless, these small variations influence Earth’s ice ages. For exoplanets, however, variations can be significantly larger. Previous studies of the habitability of moonless Earth-like exoplanets have found that high obliquities, high eccentricities, and dynamical variations can extend the outer edge of the habitable zone by preventing runaway glaciation (snowball states). We expand upon these studies by exploring the orbital dynamics with a semianalytic model that allows us to map broad regions of parameter space. We find that, in general, the largest drivers of obliquity variations are secular spin–orbit resonances. We show how the obliquity varies in several test cases, including Kepler-62 f, across a wide range of orbital and spin parameters. These obliquity variations, alongside orbital variations, will have a dramatic impact on the climates of such planets.

Seasonal variation in sports participation.

PubMed

Schüttoff, Ute; Pawlowski, Tim

2018-02-01

This study explores indicators describing socio-demographics, sports participation characteristics and motives which are associated with variation in sports participation across seasons. Data were drawn from the German Socio-Economic Panel which contains detailed information on the sports behaviour of adults in Germany. Overall, two different measures of seasonal variation are developed and used as dependent variables in our regression models. The first variable measures the coefficient of (seasonal) variation in sport-related energy expenditure per week. The second variable measures whether activity drops below the threshold as defined by the World Health Organization (WHO). Results suggest that the organisational setting, the intensity and number of sports practised, and the motive for participation are strongly correlated with the variation measures used. For example, both, participation in a sports club and a commercial facility, are associated with reduced seasonal variation and a significantly higher probability of participating at a volume above the WHO threshold across all seasons. These findings give some impetus for policymaking and the planning of sports programmes as well as future research directions.

Gray and white matter correlates of the Big Five personality traits.

PubMed

Privado, Jesús; Román, Francisco J; Saénz-Urturi, Carlota; Burgaleta, Miguel; Colom, Roberto

2017-05-04

Personality neuroscience defines the scientific study of the neurobiological basis of personality. This field assumes that individual differences in personality traits are related with structural and functional variations of the human brain. Gray and white matters are structural properties considered separately in previous research. Available findings in this regard are largely disparate. Here we analyze the relationships between gray matter (cortical thickness (CT), cortical surface area (CSA), and cortical volume) and integrity scores obtained after several white matter tracts connecting different brain regions, with individual differences in the personality traits comprised by the Five-Factor Model (extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience). These psychological and biological data were obtained from young healthy women. The main findings showed statistically significant associations between occipital CSA variations and extraversion, as well as between parietal CT variations and neuroticism. Regarding white matter integrity, openness showed positive correlations with tracts connecting posterior and anterior brain regions. Therefore, variations in discrete gray matter clusters were associated with temperamental traits (extraversion and neuroticism), whereas long-distance structural connections were related with the dimension of personality that has been associated with high-level cognitive processes (openness). Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Population structure and cultural geography of a folktale in Europe

PubMed Central

Ross, Robert M.; Greenhill, Simon J.; Atkinson, Quentin D.

2013-01-01

Despite a burgeoning science of cultural evolution, relatively little work has focused on the population structure of human cultural variation. By contrast, studies in human population genetics use a suite of tools to quantify and analyse spatial and temporal patterns of genetic variation within and between populations. Human genetic diversity can be explained largely as a result of migration and drift giving rise to gradual genetic clines, together with some discontinuities arising from geographical and cultural barriers to gene flow. Here, we adapt theory and methods from population genetics to quantify the influence of geography and ethnolinguistic boundaries on the distribution of 700 variants of a folktale in 31 European ethnolinguistic populations. We find that geographical distance and ethnolinguistic affiliation exert significant independent effects on folktale diversity and that variation between populations supports a clustering concordant with European geography. This pattern of geographical clines and clusters parallels the pattern of human genetic diversity in Europe, although the effects of geographical distance and ethnolinguistic boundaries are stronger for folktales than genes. Our findings highlight the importance of geography and population boundaries in models of human cultural variation and point to key similarities and differences between evolutionary processes operating on human genes and culture. PMID:23390109

Body size and allometric variation in facial shape in children.

PubMed

Larson, Jacinda R; Manyama, Mange F; Cole, Joanne B; Gonzalez, Paula N; Percival, Christopher J; Liberton, Denise K; Ferrara, Tracey M; Riccardi, Sheri L; Kimwaga, Emmanuel A; Mathayo, Joshua; Spitzmacher, Jared A; Rolian, Campbell; Jamniczky, Heather A; Weinberg, Seth M; Roseman, Charles C; Klein, Ophir; Lukowiak, Ken; Spritz, Richard A; Hallgrimsson, Benedikt

2018-02-01

Morphological integration, or the tendency for covariation, is commonly seen in complex traits such as the human face. The effects of growth on shape, or allometry, represent a ubiquitous but poorly understood axis of integration. We address the question of to what extent age and measures of size converge on a single pattern of allometry for human facial shape. Our study is based on two large cross-sectional cohorts of children, one from Tanzania and the other from the United States (N = 7,173). We employ 3D facial imaging and geometric morphometrics to relate facial shape to age and anthropometric measures. The two populations differ significantly in facial shape, but the magnitude of this difference is small relative to the variation within each group. Allometric variation for facial shape is similar in both populations, representing a small but significant proportion of total variation in facial shape. Different measures of size are associated with overlapping but statistically distinct aspects of shape variation. Only half of the size-related variation in facial shape can be explained by the first principal component of four size measures and age while the remainder associates distinctly with individual measures. Allometric variation in the human face is complex and should not be regarded as a singular effect. This finding has important implications for how size is treated in studies of human facial shape and for the developmental basis for allometric variation more generally. © 2017 Wiley Periodicals, Inc.

Isolation and genetic diversity of endangered grey nurse shark (Carcharias taurus) populations.

PubMed

Stow, Adam; Zenger, Kyall; Briscoe, David; Gillings, Michael; Peddemors, Victor; Otway, Nicholas; Harcourt, Robert

2006-06-22

Anthropogenic impacts are believed to be the primary threats to the eastern Australian population of grey nurse sharks (Carcharias taurus), which is listed as critically endangered, and the most threatened population globally. Analyses of 235 polymorphic amplified fragment length polymorphisms (AFLP) loci and 700 base pairs of mitochondrial DNA control region provide the first account of genetic variation and geographical partitioning (east and west coasts of Australia, South Africa) in C. taurus. Assignment tests, analysis of relatedness and Fst values all indicate that the Australian populations are isolated from South Africa, with negligible migration between the east and west Australian coasts. There are significant differences in levels of genetic variation among regions. Australian C. taurus, particularly the eastern population, has significantly less AFLP variation than the other sampling localities. Further, the eastern Australian sharks possess only a single mitochondrial haplotype, also suggesting a small number of founding individuals. Therefore, historical, rather than anthropogenic processes most likely account for their depauperate genetic variation. These findings have implications for the viability of the eastern Australian population of grey nurse sharks.

Regional Hospital Input Price Indexes

PubMed Central

Freeland, Mark S.; Schendler, Carol Ellen; Anderson, Gerard

1981-01-01

This paper describes the development of regional hospital input price indexes that is consistent with the general methodology used for the National Hospital Input Price Index. The feasibility of developing regional indexes was investigated because individuals inquired whether different regions experienced different rates of increase in hospital input prices. The regional indexes incorporate variations in cost-share weights (the amount an expense category contributes to total spending) associated with hospital type and location, and variations in the rate of input price increases for various regions. We found that between 1972 and 1979 none of the regional price indexes increased at average annual rates significantly different from the national rate. For the more recent period 1977 through 1979, the increase in one Census Region was significantly below the national rate. Further analyses indicated that variations in cost-share weights for various types of hospitals produced no substantial variations in the regional price indexes relative to the national index. We consider these findings preliminary because of limitations in the availability of current, relevant, and reliable data, especially for local area wage rate increases. PMID:10309557

Family and Asian Students' Educational Performance: A Consideration of Diversity.

ERIC Educational Resources Information Center

Blair, Sampson Lee; Qian, Zhenchao

1998-01-01

Examines variation in educational performance among students of Chinese, Filipino, Korean, Southeast Asian, and Japanese ethnicities using a sample of Asian American students from the 1992 wave of the National Educational Longitudinal Study. Finds significant differences in educational performance across the five groups. Examines causes of these…

Mothers' Work Hours and Marital Quality: Variations by Family Structure and Family Size.

ERIC Educational Resources Information Center

Rogers, Stacy J.

1996-01-01

Investigated the association between married mothers' (n=1,502) employment and their reports of marital conflict and marital happiness in continuously married families with children and in mother-stepfather families. Found significant difference between types of families. Discusses findings and calls for additional research. (RB)

Public versus Private Schools in Qatar: Is There a Literacy Gap?

ERIC Educational Resources Information Center

Cheema, Jehanzeb R.

2016-01-01

Recent studies have suggested that performance-related differences between private and public schools disappear once student background characteristics are accounted for. However, given the sometimes significant variation in economic, social and cultural norms across countries these findings may not have universal relevance. The main purpose of…

Genomic Differentiation during Speciation-with-Gene-Flow: Comparing Geographic and Host-Related Variation in Divergent Life History Adaptation in Rhagoletis pomonella

PubMed Central

Hood, Glen R.; Meyers, Peter J.; Powell, Thomas H. Q.; Lazorchak, Peter; Glover, Mary M.; Tait, Cheyenne; Hahn, Daniel A.; Berlocher, Stewart H.; Smith, James J.; Nosil, Patrik; Feder, Jeffrey L.

2018-01-01

A major goal of evolutionary biology is to understand how variation within populations gets partitioned into differences between reproductively isolated species. Here, we examine the degree to which diapause life history timing, a critical adaptation promoting population divergence, explains geographic and host-related genetic variation in ancestral hawthorn and recently derived apple-infesting races of Rhagoletis pomonella. Our strategy involved combining experiments on two different aspects of diapause (initial diapause intensity and adult eclosion time) with a geographic survey of genomic variation across four sites where apple and hawthorn flies co-occur from north to south in the Midwestern USA. The results demonstrated that the majority of the genome showing significant geographic and host-related variation can be accounted for by initial diapause intensity and eclosion time. Local genomic differences between sympatric apple and hawthorn flies were subsumed within broader geographic clines; allele frequency differences within the races across the Midwest were two to three-fold greater than those between the races in sympatry. As a result, sympatric apple and hawthorn populations displayed more limited genomic clustering compared to geographic populations within the races. The findings suggest that with reduced gene flow and increased selection on diapause equivalent to that seen between geographic sites, the host races may be recognized as different genotypic entities in sympatry, and perhaps species, a hypothesis requiring future genomic analysis of related sibling species to R. pomonella to test. Our findings concerning the way selection and geography interplay could be of broad significance for many cases of earlier stages of divergence-with-gene flow, including (1) where only modest increases in geographic isolation and the strength of selection may greatly impact genetic coupling and (2) the dynamics of how spatial and temporal standing variation is extracted by selection to generate differences between new and discrete units of biodiversity. PMID:29783692

Genomic Differentiation during Speciation-with-Gene-Flow: Comparing Geographic and Host-Related Variation in Divergent Life History Adaptation in Rhagoletis pomonella.

PubMed

Doellman, Meredith M; Ragland, Gregory J; Hood, Glen R; Meyers, Peter J; Egan, Scott P; Powell, Thomas H Q; Lazorchak, Peter; Glover, Mary M; Tait, Cheyenne; Schuler, Hannes; Hahn, Daniel A; Berlocher, Stewart H; Smith, James J; Nosil, Patrik; Feder, Jeffrey L

2018-05-18

A major goal of evolutionary biology is to understand how variation within populations gets partitioned into differences between reproductively isolated species. Here, we examine the degree to which diapause life history timing, a critical adaptation promoting population divergence, explains geographic and host-related genetic variation in ancestral hawthorn and recently derived apple-infesting races of Rhagoletis pomonella . Our strategy involved combining experiments on two different aspects of diapause (initial diapause intensity and adult eclosion time) with a geographic survey of genomic variation across four sites where apple and hawthorn flies co-occur from north to south in the Midwestern USA. The results demonstrated that the majority of the genome showing significant geographic and host-related variation can be accounted for by initial diapause intensity and eclosion time. Local genomic differences between sympatric apple and hawthorn flies were subsumed within broader geographic clines; allele frequency differences within the races across the Midwest were two to three-fold greater than those between the races in sympatry. As a result, sympatric apple and hawthorn populations displayed more limited genomic clustering compared to geographic populations within the races. The findings suggest that with reduced gene flow and increased selection on diapause equivalent to that seen between geographic sites, the host races may be recognized as different genotypic entities in sympatry, and perhaps species, a hypothesis requiring future genomic analysis of related sibling species to R. pomonella to test. Our findings concerning the way selection and geography interplay could be of broad significance for many cases of earlier stages of divergence-with-gene flow, including (1) where only modest increases in geographic isolation and the strength of selection may greatly impact genetic coupling and (2) the dynamics of how spatial and temporal standing variation is extracted by selection to generate differences between new and discrete units of biodiversity.

Radial Artery Coursing Behind the Biceps Brachii Tendon: Significance for the Transradial Catheterization and a Clinically Oriented Classification of the Radial Artery Variations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jelev, L., E-mail: ljelev@abv.bg; Surchev, L.

2008-09-15

In routine clinical practice the variations of the radial artery are the main reason for technical failure during transradial catheterization. If these variations are well documented, however, they do not represent a problem in the transradial approach. Therefore, we report here a rare case of the radial artery which is very strange but potentially valuable for the clinical practice: it arises at a right angle from the brachial artery and passes behind the biceps brachii tendon. Based on our findings and on an extensive literature review, we propose for the first time a clinically oriented classification of the variations ofmore » the radial artery. This classification is related to the catheterization success at the usual access site of the radial artery at the wrist.« less

Association of common genetic variants with human skin color variation in Indian populations.

PubMed

Sarkar, Anujit; Nandineni, Madhusudan R

2018-01-01

Human skin color is one of the most conspicuously variable physical traits that has attracted the attention of physical anthropologists, social scientists and human geneticists. Although several studies have established the underlying genes and their variants affecting human skin color, they were mostly confined to Europeans and Africans and similar studies in Indian populations have been scanty. Studying the association between candidate genetic variants and skin color will help to validate previous findings and to better understand the molecular mechanism of skin color variation. In this study, 22 candidate SNPs from 12 genes were tested for association with skin color in 299 unrelated samples sourced from nine geographical locations in India. Our study establishes the association of 9 SNPs with the phenotype in Indian populations and could explain ∼31% of the variance in skin color. Haplotype analysis of chromosome 15 revealed a significant association of alleles G, A and C of SNPs rs1426654, rs11070627, and rs12913316, respectively, to the phenotype, and accounted for 17% of the variance. Latitude of the sampling location was also a significant factor, contributing to ∼19% of the variation observed in the samples. These observations support the findings that rs1426654 and rs4775730 located in SLC24A5, and rs11070627 and rs12913316 located in MYEF2 and CTXN2 genes respectively, are major contributors toward skin pigmentation and would aid in further unraveling the genotype-phenotype association in Indian populations. These findings can be utilized in forensic DNA applications for criminal investigations. © 2017 Wiley Periodicals, Inc.

The effects of different concentrations of cocoa in the chocolate intaken by the mother on fetal heart rate.

PubMed

Buscicchio, Giorgia; Lorenzi, Sara; Tranquilli, Andrea Luigi

2013-10-01

To analyze the effects of different concentrations (30% and 80%) of cocoa on fetal heart rate (FHR). One hundred pregnant women with uncomplicated gestation, matched for age and parity, underwent computerized FHR recording before and after the consumption of 30 g of 30% and 80% cocoa chocolate. After 1 week, those who had received 30% were shifted to 80% and vice versa to have a crossover. Computerized cardiotocography parameters (contractions, fetal movements, baseline FHR, accelerations greater than 15 bpm for 15 s, number of decelerations, minutes of high variability, short term variability in ms) were recorded and expressed as mean and SD. The differences were tested for statistical significance using the paired t test, with the significance at p < 0.05. The percent change after chocolate intake for accelerations and short-term FHR variation was calculated. The number of fetal movements, accelerations, the duration of episodes of high variation and the short-term FHR variation were significantly higher (p < 0.0001) after 80% cocoa intake. After 30% cocoa chocolate intake, only the number of accelerations was significantly increased. The percent change of the number of accelerations and the short-term FHR variation were significantly higher after 80% cocoa chocolate maternal intake. Maternal intake of dark chocolate has a stimulating action on fetal reactivity. The effect is more marked with high concentrations (80%) of cocoa. This finding is likely due to the pharmacological action of theobromine, a methilxanthine present in cocoa.

Sesquiterpene lactone stereochemistry influences herbivore resistance and plant fitness in the field

PubMed Central

Ahern, Jeffrey R.; Whitney, Kenneth D.

2014-01-01

Background and Aims Stereochemical variation is widely known to influence the bioactivity of compounds in the context of pharmacology and pesticide science, but our understanding of its importance in mediating plant–herbivore interactions is limited, particularly in field settings. Similarly, sesquiterpene lactones are a broadly distributed class of putative defensive compounds, but little is known about their activities in the field. Methods Natural variation in sesquiterpene lactones of the common cocklebur, Xanthium strumarium (Asteraceae), was used in conjunction with a series of common garden experiments to examine relationships between stereochemical variation, herbivore damage and plant fitness. Key Results The stereochemistry of sesquiterpene lactone ring junctions helped to explain variation in plant herbivore resistance. Plants producing cis-fused sesquiterpene lactones experienced significantly higher damage than plants producing trans-fused sesquiterpene lactones. Experiments manipulating herbivore damage above and below ambient levels found that herbivore damage was negatively correlated with plant fitness. This pattern translated into significant fitness differences between chemotypes under ambient levels of herbivore attack, but not when attack was experimentally reduced via pesticide. Conclusions To our knowledge, this work represents only the second study to examine sesquiterpene lactones as defensive compounds in the field, the first to document herbivore-mediated natural selection on sesquiterpene lactone variation and the first to investigate the ecological significance of the stereochemistry of the lactone ring junction. The results indicate that subtle differences in stereochemistry may be a major determinant of the protective role of secondary metabolites and thus of plant fitness. As stereochemical variation is widespread in many groups of secondary metabolites, these findings suggest the possibility of dynamic evolutionary histories within the Asteraceae and other plant families showing extensive stereochemical variation. PMID:24380844

Sesquiterpene lactone stereochemistry influences herbivore resistance and plant fitness in the field.

PubMed

Ahern, Jeffrey R; Whitney, Kenneth D

2014-03-01

Stereochemical variation is widely known to influence the bioactivity of compounds in the context of pharmacology and pesticide science, but our understanding of its importance in mediating plant-herbivore interactions is limited, particularly in field settings. Similarly, sesquiterpene lactones are a broadly distributed class of putative defensive compounds, but little is known about their activities in the field. Natural variation in sesquiterpene lactones of the common cocklebur, Xanthium strumarium (Asteraceae), was used in conjunction with a series of common garden experiments to examine relationships between stereochemical variation, herbivore damage and plant fitness. The stereochemistry of sesquiterpene lactone ring junctions helped to explain variation in plant herbivore resistance. Plants producing cis-fused sesquiterpene lactones experienced significantly higher damage than plants producing trans-fused sesquiterpene lactones. Experiments manipulating herbivore damage above and below ambient levels found that herbivore damage was negatively correlated with plant fitness. This pattern translated into significant fitness differences between chemotypes under ambient levels of herbivore attack, but not when attack was experimentally reduced via pesticide. To our knowledge, this work represents only the second study to examine sesquiterpene lactones as defensive compounds in the field, the first to document herbivore-mediated natural selection on sesquiterpene lactone variation and the first to investigate the ecological significance of the stereochemistry of the lactone ring junction. The results indicate that subtle differences in stereochemistry may be a major determinant of the protective role of secondary metabolites and thus of plant fitness. As stereochemical variation is widespread in many groups of secondary metabolites, these findings suggest the possibility of dynamic evolutionary histories within the Asteraceae and other plant families showing extensive stereochemical variation.

Allelic Variation of Risk for Anxiety Symptoms Moderates the Relation Between Adolescent Safety Behaviors and Social Anxiety Symptoms

PubMed Central

Thomas, Sarah A.; Weeks, Justin W.; Dougherty, Lea R.; Lipton, Melanie F.; Daruwala, Samantha E.; Kline, Kathryn

2015-01-01

Social anxiety often develops in adolescence, and precedes the onset of depression and substance use disorders. The link between social anxiety and use of behaviors to minimize distress in social situations (i.e., safety behaviors) is strong and for some patients, this link poses difficulty for engaging in, and benefiting from, exposure-based treatment. Yet, little is known about whether individual differences may moderate links between social anxiety and safety behaviors, namely variations in genetic alleles germane to anxiety. We examined the relation between adolescent social anxiety and expressions of safety behaviors, and whether allelic variation for anxiety moderates this relation. Adolescents (n=75; ages 14–17) were recruited from two larger studies investigating measurement of family relationships or adolescent social anxiety. Adolescents completed self-report measures about social anxiety symptoms and use of safety behaviors. They also provided saliva samples to assess allelic variations for anxiety from two genetic polymorphisms (BDNF rs6265; TAQ1A rs1800497). Controlling for adolescent age and gender, we observed a significant interaction between social anxiety symptoms and allelic variation (β=0.37, t=2.41, p=.02). Specifically, adolescents carrying allelic variations for anxiety evidenced a statistically significant and relatively strong positive relation between social anxiety symptoms and safety behaviors (β=0.73), whereas adolescents not carrying allelic variation evidenced a statistically non-significant and relatively weak relation (β=0.22). These findings have important implications for treating adolescent social anxiety, in that we identified an individual difference variable that can be used to identify people who evidence a particularly strong link between use of safety behaviors and expressing social anxiety. PMID:26692635

Comparative morphology among northern populations of breeding Cooper's Hawks

USGS Publications Warehouse

Rosenfield, Robert N.; Rosenfield, Laura J.; Bielefeldt, John; Murphy, Robert K.; Stewart, Andrew C.; Stout, William E.; Driscoll, Timothy G.; Bozek, Michael A.

2010-01-01

Few studies at a broad geographical scale have characterized intraspecific variation in morphology of woodland hawks in the genus Accipiter. From 1999 to 2007 we investigated morphological variation in large samples of live Cooper's Hawks (A. cooperii) nesting in four study areas: coniferous woodland around Victoria, British Columbia, Canada, isolated deciduous woodlands in short-grass prairies of northwestern North Dakota, towns and rural deciduous woodlands along the border of North Dakota and Minnesota, and urban and rural mixed deciduous and coniferous landscapes of Wisconsin. These sites span 2660 km across the northern part of the species' breeding range. We measured body mass (i.e., size), wing chord, tail length, tarsus diameter, hallux length, and culmen length of breeding adults, finding significant and clinal variation in body mass (or size). The smallest and most similar-sized birds occurred in British Columbia and western North Dakota, larger birds along the border between North Dakota and Minnesota, and the largest birds in Wisconsin. Several other characters varied significantly when mass was used as a covariate. Variation by study site in mean indices of sexual size dimorphism was negligible and not significant. We speculate that the morphological differences we found, in part, are the result of geographic isolation, where diets, migratory behavior, and structural characteristics of nesting habitats vary across landscape types.

Oceanographic variation influences spatial genomic structure in the sea scallop, Placopecten magellanicus.

PubMed

Van Wyngaarden, Mallory; Snelgrove, Paul V R; DiBacco, Claudio; Hamilton, Lorraine C; Rodríguez-Ezpeleta, Naiara; Zhan, Luyao; Beiko, Robert G; Bradbury, Ian R

2018-03-01

Environmental factors can influence diversity and population structure in marine species and accurate understanding of this influence can both improve fisheries management and help predict responses to environmental change. We used 7163 SNPs derived from restriction site-associated DNA sequencing genotyped in 245 individuals of the economically important sea scallop, Placopecten magellanicus , to evaluate the correlations between oceanographic variation and a previously identified latitudinal genomic cline. Sea scallops span a broad latitudinal area (>10 degrees), and we hypothesized that climatic variation significantly drives clinal trends in allele frequency. Using a large environmental dataset, including temperature, salinity, chlorophyll a, and nutrient concentrations, we identified a suite of SNPs (285-621, depending on analysis and environmental dataset) potentially under selection through correlations with environmental variation. Principal components analysis of different outlier SNPs and environmental datasets revealed similar northern and southern clusters, with significant associations between the first axes of each ( R 2 adj  = .66-.79). Multivariate redundancy analysis of outlier SNPs and the environmental principal components indicated that environmental factors explained more than 32% of the variance. Similarly, multiple linear regressions and random-forest analysis identified winter average and minimum ocean temperatures as significant parameters in the link between genetic and environmental variation. This work indicates that oceanographic variation is associated with the observed genomic cline in this species and that seasonal periods of extreme cold may restrict gene flow along a latitudinal gradient in this marine benthic bivalve. Incorporating this finding into management may improve accuracy of management strategies and future predictions.

Multiple Transcript Properties Related to Translation Affect mRNA Degradation Rates in Saccharomyces cerevisiae

PubMed Central

Neymotin, Benjamin; Ettorre, Victoria; Gresham, David

2016-01-01

Degradation of mRNA contributes to variation in transcript abundance. Studies of individual mRNAs have shown that both cis and trans factors affect mRNA degradation rates. However, the factors underlying transcriptome-wide variation in mRNA degradation rates are poorly understood. We investigated the contribution of different transcript properties to transcriptome-wide degradation rate variation in the budding yeast, Saccharomyces cerevisiae, using multiple regression analysis. We find that multiple transcript properties are significantly associated with variation in mRNA degradation rates, and that a model incorporating these properties explains ∼50% of the genome-wide variance. Predictors of mRNA degradation rates include transcript length, ribosome density, biased codon usage, and GC content of the third position in codons. To experimentally validate these factors, we studied individual transcripts expressed from identical promoters. We find that decreasing ribosome density by mutating the first translational start site of a transcript increases its degradation rate. Using coding sequence variants of green fluorescent protein (GFP) that differ only at synonymous sites, we show that increased GC content of the third position of codons results in decreased rates of mRNA degradation. Thus, in steady-state conditions, a large fraction of genome-wide variation in mRNA degradation rates is determined by inherent properties of transcripts, many of which are related to translation, rather than specific regulatory mechanisms. PMID:27633789

Common genetic variation in ETV6 is associated with colorectal cancer susceptibility

PubMed Central

Wang, Meilin; Gu, Dongying; Du, Mulong; Xu, Zhi; Zhang, Suzhan; Zhu, Lingjun; Lu, Jiachun; Zhang, Rui; Xing, Jinliang; Miao, Xiaoping; Chu, Haiyan; Hu, Zhibin; Yang, Lei; Tang, Cuiju; Pan, Lei; Du, Haina; Zhao, Jian; Du, Jiangbo; Tong, Na; Sun, Jielin; Shen, Hongbing; Xu, Jianfeng; Zhang, Zhengdong; Chen, Jinfei

2016-01-01

Genome-wide association studies (GWASs) have identified multiple susceptibility loci for colorectal cancer, but much of heritability remains unexplained. To identify additional susceptibility loci for colorectal cancer, here we perform a GWAS in 1,023 cases and 1,306 controls and replicate the findings in seven independent samples from China, comprising 5,317 cases and 6,887 controls. We find a variant at 12p13.2 associated with colorectal cancer risk (rs2238126 in ETV6, P=2.67 × 10−10). We replicate this association in an additional 1,046 cases and 1,076 controls of European ancestry (P=0.034). The G allele of rs2238126 confers earlier age at onset of colorectal cancer (P=1.98 × 10−6) and reduces the binding affinity of transcriptional enhancer MAX. The mRNA level of ETV6 is significantly lower in colorectal tumours than in paired normal tissues. Our findings highlight the potential importance of genetic variation in ETV6 conferring susceptibility to colorectal cancer. PMID:27145994

Use of spectral analogy to evaluate canopy reflectance sensitivity to leaf optical property

NASA Technical Reports Server (NTRS)

Baret, Frederic; Vanderbilt, Vern C.; Steven, Michael D.; Jacquemoud, Stephane

1993-01-01

The spectral variation of canopy reflectance is mostly governed by the absorption properties of the elements, hence the leaves, since their intrinsic scattering properties show very little spectral variation. The relationship between canopy reflectance and leaf reflectance measured at the red edge over sugar beet canopies was used to simulate canopy reflectance from leaf reflectance spectra measured over the whole spectral domain. The results show that the spectral analogies found allows accurate reconstruction of canopy reflectance spectra. Explicit assumptions about the very low spectral variation of leaf intrinsic scattering properties are thus indirectly justified. The sensitivity of canopy reflectance (rho(sub c)) to leaf optical properties can then be investigated from concurrent spectral variations of canopy (delta rho(sub c)/delta lambda) and leaf reflectance (delta rho(sub l)/delta lambda): (delta rho(sub c))/(delta rho(sub l)) = ((delta rho(sub c))/(delta lambda) ((delta rho( sub l))/(delta lambda))(sup -1)). This expression is strictly valid only when the optical properties of the soil background or the other vegetation elements such as bark are either spectrally flat or do not contribute significantly to canopy reflectance. Simulations using the SAIL and PROSPECT models demonstrate that the sensitivity of canopy reflectance to leaf reflectance is significant for large vegetation cover fractions in spectral domains where absorption is low. In these conditions, multiple, scattering enhances the leaf absorption features by a factor that can be greater than 2.0. To override the limitations of the SAIL model for the description of the canopy architecture, we tested the previous findings on experimental data. Concurrent canopy and leaf reflectance spectra were measured for a range of sugar beet canopies. The results show good agreement with the theoretical findings. Conclusions are drawn about the applicability of these findings, with particular attention to the potential detectability of leaf biochemical composition from canopy reflectance sensed from space.

Population genomics of Pacific lamprey: adaptive variation in a highly dispersive species.

PubMed

Hess, Jon E; Campbell, Nathan R; Close, David A; Docker, Margaret F; Narum, Shawn R

2013-06-01

Unlike most anadromous fishes that have evolved strict homing behaviour, Pacific lamprey (Entosphenus tridentatus) seem to lack philopatry as evidenced by minimal population structure across the species range. Yet unexplained findings of within-region population genetic heterogeneity coupled with the morphological and behavioural diversity described for the species suggest that adaptive genetic variation underlying fitness traits may be responsible. We employed restriction site-associated DNA sequencing to genotype 4439 quality filtered single nucleotide polymorphism (SNP) loci for 518 individuals collected across a broad geographical area including British Columbia, Washington, Oregon and California. A subset of putatively neutral markers (N = 4068) identified a significant amount of variation among three broad populations: northern British Columbia, Columbia River/southern coast and 'dwarf' adults (F(CT) = 0.02, P ≪ 0.001). Additionally, 162 SNPs were identified as adaptive through outlier tests, and inclusion of these markers revealed a signal of adaptive variation related to geography and life history. The majority of the 162 adaptive SNPs were not independent and formed four groups of linked loci. Analyses with matsam software found that 42 of these outlier SNPs were significantly associated with geography, run timing and dwarf life history, and 27 of these 42 SNPs aligned with known genes or highly conserved genomic regions using the genome browser available for sea lamprey. This study provides both neutral and adaptive context for observed genetic divergence among collections and thus reconciles previous findings of population genetic heterogeneity within a species that displays extensive gene flow. © 2012 John Wiley & Sons Ltd.

Azimuth cut-off model for significant wave height investigation along coastal water of Kuala Terengganu, Malaysia

NASA Astrophysics Data System (ADS)

Marghany, Maged; Ibrahim, Zelina; Van Genderen, Johan

2002-11-01

The present work is used to operationalize the azimuth cut-off concept in the study of significant wave height. Three ERS-1 images have been used along the coastal waters of Terengganu, Malaysia. The quasi-linear transform was applied to map the SAR wave spectra into real ocean wave spectra. The azimuth cut-off was then used to model the significant wave height. The results show that azimuth cut-off varied with the different period of the ERS-1 images. This is because of the fact that the azimuth cut-off is a function of wind speed and significant wave height. It is of interest to find that the significant wave height modeled from azimuth cut-off is in good relation with ground wave conditions. It can be concluded that ERS-1 can be used as a monitoring tool in detecting the significant wave height variation. The azimuth cut-off can be used to model the significant wave height. This means that the quasi-linear transform could be a good application to significant wave height variation during different seasons.

Epigenetic Variation in Mangrove Plants Occurring in Contrasting Natural Environment

PubMed Central

Lira-Medeiros, Catarina Fonseca; Parisod, Christian; Fernandes, Ricardo Avancini; Mata, Camila Souza; Cardoso, Monica Aires; Ferreira, Paulo Cavalcanti Gomes

2010-01-01

Background Epigenetic modifications, such as cytosine methylation, are inherited in plant species and may occur in response to biotic or abiotic stress, affecting gene expression without changing genome sequence. Laguncularia racemosa, a mangrove species, occurs in naturally contrasting habitats where it is subjected daily to salinity and nutrient variations leading to morphological differences. This work aims at unraveling how CpG-methylation variation is distributed among individuals from two nearby habitats, at a riverside (RS) or near a salt marsh (SM), with different environmental pressures and how this variation is correlated with the observed morphological variation. Principal Findings Significant differences were observed in morphological traits such as tree height, tree diameter, leaf width and leaf area between plants from RS and SM locations, resulting in smaller plants and smaller leaf size in SM plants. Methyl-Sensitive Amplified Polymorphism (MSAP) was used to assess genetic and epigenetic (CpG-methylation) variation in L. racemosa genomes from these populations. SM plants were hypomethylated (14.6% of loci had methylated samples) in comparison to RS (32.1% of loci had methylated samples). Within-population diversity was significantly greater for epigenetic than genetic data in both locations, but SM also had less epigenetic diversity than RS. Frequency-based (GST) and multivariate (βST) methods that estimate population structure showed significantly greater differentiation among locations for epigenetic than genetic data. Co-Inertia analysis, exploring jointly the genetic and epigenetic data, showed that individuals with similar genetic profiles presented divergent epigenetic profiles that were characteristic of the population in a particular environment, suggesting that CpG-methylation changes may be associated with environmental heterogeneity. Conclusions In spite of significant morphological dissimilarities, individuals of L. racemosa from salt marsh and riverside presented little genetic but abundant DNA methylation differentiation, suggesting that epigenetic variation in natural plant populations has an important role in helping individuals to cope with different environments. PMID:20436669

Lunar and Solar Torques on the Oceanic Tides

NASA Technical Reports Server (NTRS)

Ray, Richard D.; Bills, Bruce G.; Chao, Benjamin F.

1998-01-01

Brosche and Seiler recently suggested that direct lunar and solar tidal torques on the oceanic tides play a significant role in the earth's short-period angular momentum balance ("short-period" here meaning daily and sub-daily). We reexamine that suggestion here, concentrating on axial torques and hence on variations in rotation rate. Only those spherical harmonic components of the ocean tide having the same degree and order as the tidal potential induce nonzero torques. Prograde components (those moving in the same direction as the tide-generating body) produce the familiar secular braking of the earth's rotation. Retrograde components, however, produce rapid variations in UTI at twice the tidal frequency. There also exist interaction torques between tidal constituents, e.g. solar torques on lunar tides. They generate UTI variations at frequencies equal to the sums and differences of the original tidal frequencies. We give estimates of the torques and angular momentum variations for each of the important regimes, secular to quarter-diurnal. For the M(sub 2) potential acting on the M(sub 2) ocean tide, we find an associated angular momentum variation of amplitude 3 x 10(exp 19) N m. This is 5 to 6 orders of magnitude smaller than the angular momentum variations associated with tidal currents. We conclude that these torques do not play a significant role in the short-period angular momentum balance.

The Complex Contributions of Genetics and Nutrition to Immunity in Drosophila melanogaster

PubMed Central

Unckless, Robert L.; Rottschaefer, Susan M.; Lazzaro, Brian P.

2015-01-01

Both malnutrition and undernutrition can lead to compromised immune defense in a diversity of animals, and “nutritional immunology” has been suggested as a means of understanding immunity and determining strategies for fighting infection. The genetic basis for the effects of diet on immunity, however, has been largely unknown. In the present study, we have conducted genome-wide association mapping in Drosophila melanogaster to identify the genetic basis for individual variation in resistance, and for variation in immunological sensitivity to diet (genotype-by-environment interaction, or GxE). D. melanogaster were reared for several generations on either high-glucose or low-glucose diets and then infected with Providencia rettgeri, a natural bacterial pathogen of D. melanogaster. Systemic pathogen load was measured at the peak of infection intensity, and several indicators of nutritional status were taken from uninfected flies reared on each diet. We find that dietary glucose level significantly alters the quality of immune defense, with elevated dietary glucose resulting in higher pathogen loads. The quality of immune defense is genetically variable within the sampled population, and we find genetic variation for immunological sensitivity to dietary glucose (genotype-by-diet interaction). Immune defense was genetically correlated with indicators of metabolic status in flies reared on the high-glucose diet, and we identified multiple genes that explain variation in immune defense, including several that have not been previously implicated in immune response but which are confirmed to alter pathogen load after RNAi knockdown. Our findings emphasize the importance of dietary composition to immune defense and reveal genes outside the conventional “immune system” that can be important in determining susceptibility to infection. Functional variation in these genes is segregating in a natural population, providing the substrate for evolutionary response to pathogen pressure in the context of nutritional environment. PMID:25764027

The complex contributions of genetics and nutrition to immunity in Drosophila melanogaster.

PubMed

Unckless, Robert L; Rottschaefer, Susan M; Lazzaro, Brian P

2015-03-01

Both malnutrition and undernutrition can lead to compromised immune defense in a diversity of animals, and "nutritional immunology" has been suggested as a means of understanding immunity and determining strategies for fighting infection. The genetic basis for the effects of diet on immunity, however, has been largely unknown. In the present study, we have conducted genome-wide association mapping in Drosophila melanogaster to identify the genetic basis for individual variation in resistance, and for variation in immunological sensitivity to diet (genotype-by-environment interaction, or GxE). D. melanogaster were reared for several generations on either high-glucose or low-glucose diets and then infected with Providencia rettgeri, a natural bacterial pathogen of D. melanogaster. Systemic pathogen load was measured at the peak of infection intensity, and several indicators of nutritional status were taken from uninfected flies reared on each diet. We find that dietary glucose level significantly alters the quality of immune defense, with elevated dietary glucose resulting in higher pathogen loads. The quality of immune defense is genetically variable within the sampled population, and we find genetic variation for immunological sensitivity to dietary glucose (genotype-by-diet interaction). Immune defense was genetically correlated with indicators of metabolic status in flies reared on the high-glucose diet, and we identified multiple genes that explain variation in immune defense, including several that have not been previously implicated in immune response but which are confirmed to alter pathogen load after RNAi knockdown. Our findings emphasize the importance of dietary composition to immune defense and reveal genes outside the conventional "immune system" that can be important in determining susceptibility to infection. Functional variation in these genes is segregating in a natural population, providing the substrate for evolutionary response to pathogen pressure in the context of nutritional environment.

Country variations in depressive symptoms profile in Asian countries: Findings of the Research on Asia Psychotropic Prescription (REAP) studies.

PubMed

Chee, Kok-Yoon; Tripathi, Adarsh; Avasthi, Ajit; Chong, Mian-Yoon; Xiang, Yu-Tao; Sim, Kang; Si, Tian-Mei; Kanba, Shigenobu; He, Yan-Ling; Lee, Min-Soo; Fung-Kum Chiu, Helen; Yang, Shu-Yu; Kuga, Hironori; Udormatn, Pichet; Kallivayalil, Roy A; Tanra, Andi J; Maramis, Margarita; Grover, Sandeep; Chin, Loi-Fei; Dahlan, Rahima; Mohamad Isa, Mohd Fadzli; Ebenezer, Esther Gunaseli M; Nordin, Norhayati; Shen, Winston W; Shinfuku, Naotaka; Tan, Chay-Hoon; Sartorius, Norman

2015-09-01

This study was to assess differences in the symptom profile of depressive illness across various countries/territories in Asia. The study was a part of the Research on Asia Psychotropic Prescription project. The participating countries/territories include China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Singapore, Taiwan, and Thailand. The pattern of depressive symptoms in 1,400 subjects with depressive disorder from 42 psychiatric centers in 10 Asian countries/territories was assessed. We collected information on socio-demographic and clinical characteristics with a standardized protocol and data collection procedure. The most common presentations of depressive symptoms were persistent sadness, loss of interest, and insomnia. Similar findings were found regardless of the region, country, or its income level. Patients with depressive disorder from high-income countries presented significantly more with vegetative symptom cluster (P < 0.05), while those from the upper middle-income countries had significantly more with both mood (P < 0.001) and cognitive symptom clusters (P < 0.01). In lower middle-income countries, patients with depressive symptoms had significantly less mood symptom cluster (P < 0.001) but significantly more cognitive symptom cluster (P < 0.05). This study demonstrates that in Asia, despite variations in the initial symptom reported by the patients, across different countries/territories, core depressive symptoms remain the same. Variations have been found in presentation of depressive symptoms with regards to the level of income of countries. Physical or vegetative symptoms were reported more by centers in higher income countries, while depressive cognition and suicidal thoughts/acts were more frequently reported from lower income countries. © 2015 Wiley Publishing Asia Pty Ltd.

Influence of stuttering variation on talker group classification in preschool children: Preliminary findings

PubMed Central

Johnson, Kia N.; Karrass, Jan; Conture, Edward G.; Walden, Tedra

2010-01-01

The purpose of this study was to investigate whether variations in disfluencies of young children who do (CWS) and do not stutter (CWNS) significantly change their talker group classification or diagnosis from stutterer to nonstutterer, and vice versa. Participants consisted of 17 3- to 5-year-old CWS and 9 3- to 5-year-old CWNS, with no statistically significant between-group difference in chronological age (CWS: M = 45.53 months, SD = 8.32; CWNS: M = 47.67 months, SD = 6.69). All participants had speech, language, and hearing development within normal limits, with the exception of stuttering for CWS. Both talker groups participated in a series of speaking samples that varied by: (a) conversational partner [parent and clinician], (b) location [home and clinic], and (c) context [conversation and narrative]. The primary dependent measures for this study were the number of stuttering-like disfluencies (SLD) per total number of spoken words [%SLD] and the ratio of SLD to total disfluencies (TD) [SLD/TD]. Results indicated that significant variability of stuttering did not exist as a result of conversational partner or location. Changes in context, however, did impact the CWS, who demonstrated higher SLD/TD in the conversation sample versus a narrative sample. Consistent with hypotheses, CWS and CWNS were accurately identified as stutterers and nonstutterers, respectively, regardless of changes to conversational partner, location or context for the overall participant sample. Present findings were taken to suggest that during assessment, variations in stuttering frequency resulting from changes in conversational partner, location or context do not significantly influence the diagnosis of stuttering, especially for children not on the talker group classification borderline between CWS and CWNS. PMID:19167719

Developmental pathways from child maltreatment to adolescent marijuana dependence: Examining moderation by FKBP5

PubMed Central

Handley, Elizabeth D.; Rogosch, Fred A.; Cicchetti, Dante

2015-01-01

The current study examined the prospective association between child maltreatment and the development of substance use disorder (SUD) in adolescence with the aim of investigating pathways underlying this relation, as well as genetic moderation of these developmental mechanisms. Specifically, we tested whether youth who experienced maltreatment prior to age 8 were at risk for the development of marijuana dependence in adolescence by way of a childhood externalizing pathway and a childhood internalizing pathway. Moreover, we tested whether variation in FKBP5 CATT haplotype moderated these pathways. The participants were 326 children (n=179 maltreated; n=147 nonmaltreated) assessed across two waves of data collection (childhood: ages 7–9 and adolescence: ages 15–18). Results indicated that higher levels of child externalizing symptoms significantly mediated the effect of child maltreatment on adolescent marijuana dependence symptoms for individuals with 1–2 copies of the FKBP5 CATT haplotype only. We did not find support for an internalizing pathway from child maltreatment to adolescent marijuana dependence, nor did we find evidence of moderation of the internalizing pathway by FKBP5 haplotype variation. Findings extend previous research by demonstrating that whether a maltreated child will traverse an externalizing pathway toward SUD in adolescence is dependent on FKBP5 genetic variation. PMID:26535939

Inbreeding depression by environment interactions in a free-living mammal population

PubMed Central

Pemberton, J M; Ellis, P E; Pilkington, J G; Bérénos, C

2017-01-01

Experimental studies often find that inbreeding depression is more severe in harsh environments, but the few studies of in situ wild populations available to date rarely find strong support for this effect. We investigated evidence for inbreeding depression by environment interactions in nine traits in the individually monitored Soay sheep population of St Kilda, using genomic inbreeding coefficients based on 37 037 single-nucleotide polymorphism loci, and population density as an axis of environmental variation. All traits showed variation with population density and all traits showed some evidence for depression because of either an individual's own inbreeding or maternal inbreeding. However, only six traits showed evidence for an interaction in the expected direction, and only two interactions were statistically significant. We identify three possible reasons why wild population studies may generally fail to find strong support for interactions between inbreeding depression and environmental variation compared with experimental studies. First, for species with biparental inbreeding only, the amount of observed inbreeding in natural populations is generally low compared with that used in experimental studies. Second, it is possible that experimental studies sometimes actually impose higher levels of stress than organisms experience in the wild. Third, some purging of the deleterious recessive alleles that underpin interaction effects may occur in the wild. PMID:27876804

Inbreeding depression by environment interactions in a free-living mammal population.

PubMed

Pemberton, J M; Ellis, P E; Pilkington, J G; Bérénos, C

2017-01-01

Experimental studies often find that inbreeding depression is more severe in harsh environments, but the few studies of in situ wild populations available to date rarely find strong support for this effect. We investigated evidence for inbreeding depression by environment interactions in nine traits in the individually monitored Soay sheep population of St Kilda, using genomic inbreeding coefficients based on 37 037 single-nucleotide polymorphism loci, and population density as an axis of environmental variation. All traits showed variation with population density and all traits showed some evidence for depression because of either an individual's own inbreeding or maternal inbreeding. However, only six traits showed evidence for an interaction in the expected direction, and only two interactions were statistically significant. We identify three possible reasons why wild population studies may generally fail to find strong support for interactions between inbreeding depression and environmental variation compared with experimental studies. First, for species with biparental inbreeding only, the amount of observed inbreeding in natural populations is generally low compared with that used in experimental studies. Second, it is possible that experimental studies sometimes actually impose higher levels of stress than organisms experience in the wild. Third, some purging of the deleterious recessive alleles that underpin interaction effects may occur in the wild.

Theoretical studies of the work functions of Pd-based bimetallic surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Zhao-Bin; Wu, Feng; Wang, Yue-Chao

2015-06-07

Work functions of Pd-based bimetallic surfaces, including mainly M/Pd(111), Pd/M, and Pd/M/Pd(111) (M = 4d transition metals, Cu, Au, and Pt), are studied using density functional theory. We find that the work function of these bimetallic surfaces is significantly different from that of parent metals. Careful analysis based on Bader charges and electron density difference indicates that the variation of the work function in bimetallic surfaces can be mainly attributed to two factors: (1) charge transfer between the two different metals as a result of their different intrinsic electronegativity, and (2) the charge redistribution induced by chemical bonding between themore » top two layers. The first factor can be related to the contact potential, i.e., the work function difference between two metals in direct contact, and the second factor can be well characterized by the change in the charge spilling out into vacuum. We also find that the variation in the work functions of Pd/M/Pd(111) surfaces correlates very well with the variation of the d-band center of the surface Pd atom. The findings in this work can be used to provide general guidelines to design new bimetallic surfaces with desired electronic properties.« less

Racial Variation in the Effect of Incarceration on Neighborhood Attainment

PubMed Central

Massoglia, Michael; Firebaugh, Glenn; Warner, Cody

2013-01-01

Each year, more than 700,000 convicted offenders are released from prison and reenter neighborhoods across the country. Prior studies have found that minority ex-inmates tend to reside in more disadvantaged neighborhoods than do white ex-inmates. However, because these studies do not control for pre-prison neighborhood conditions, we do not know how much (if any) of this racial variation is due to arrest and incarceration, or if these observed findings simply reflect existing racial residential inequality. Using a nationally representative dataset that tracks individuals over time, we find that only whites live in significantly more disadvantaged neighborhoods after prison than prior to prison. Blacks and Hispanics do not, nor do all groups (whites, blacks, and Hispanics) as a whole live in worse neighborhoods after prison. We attribute this racial variation in the effect of incarceration to the high degree of racial neighborhood inequality in the United States: because white offenders generally come from much better neighborhoods, they have much more to lose from a prison spell. In addition to advancing our understanding of the social consequences of the expansion of the prison population, these findings demonstrate the importance of controlling for preprison characteristics when investigating the effects of incarceration on residential outcomes. PMID:24367134

Genomics of immune response to typhoid and cholera vaccines

PubMed Central

Majumder, Partha P.

2015-01-01

Considerable variation in antibody response (AR) was observed among recipients of an injectable typhoid vaccine and an oral cholera vaccine. We sought to find whether polymorphisms in genes of the immune system, both innate and adaptive, were associated with the observed variation in response. For both vaccines, we were able to discover and validate several polymorphisms that were significantly associated with immune response. For the typhoid vaccines, these polymorphisms were on genes that belonged to pathways of polysaccharide recognition, signal transduction, inhibition of T-cell proliferation, pro-inflammatory signalling and eventual production of antimicrobial peptides. For the cholera vaccine, the pathways included epithelial barrier integrity, intestinal homeostasis and leucocyte recruitment. Even though traditional wisdom indicates that both vaccines should act as T-cell-independent antigens, our findings reveal that the vaccines induce AR using different pathways. PMID:25964454

Gubernatorial Authority and Influence on Public Higher Education

ERIC Educational Resources Information Center

Christakis, Michael N.

2009-01-01

State governors have the potential to impact their states' public higher education systems in a variety of very significant ways. The findings for the 33 governors included in this study suggest a great deal of variation in the extent of their authority and influence. Governors' composite ratings of formal authority and informal influence are…

Reactions to Lexical, Syntactical, and Text Layout Variations of a Print Advertisement.

ERIC Educational Resources Information Center

Motes, William H.; And Others

1992-01-01

Assesses reader reactions to a broad range of lexical, syntactical, and text layout conditions, both in isolation and interactively. Finds that, although the role of these elements in affecting readers' perceptions is not as critical as was presumed, certain perceptions are significantly affected by specific lexical, syntactical, and layout…

Regional Variation in mtDNA of the Lesser Prairie-Chicken

USGS Publications Warehouse

Hagen, Christian A.; Pitman, James C.; Sandercock, Brett K.; Wolfe, Don H.; Robel, Robel J.; Applegate, Roger D.; Oyler-McCance, Sara J.

2010-01-01

Cumulative loss of habitat and long-term decline in the populations of the Lesser Prairie-Chicken (Tympanuchus pallidicinctus) have led to concerns for the species' viability throughout its range in the southern Great Plains. For more efficient conservation past and present distributions of genetic variation need to be understood. We examined the distribution of mitochondrial DNA (mtDNA) variation in the Lesser Prairie-Chicken across Kansas, Colorado, Oklahoma, and New Mexico. Throughout the range we found little genetic differentiation except for the population in New Mexico, which was significantly different from most other publications. We did, however, find significant isolation by distance at the rangewide scale (r=0.698). We found no relationship between haplotype phylogeny and geography, and our analyses provide evidence for a post-glacial population expansion within the species that is consistent with the idea that speciation within Tympanuchus is recent. Conservation actions that increase the likelihood of genetically viable populations in the future should be evaluated for implementation.

Identifying with fictive characters: structural brain correlates of the personality trait ‘fantasy’

PubMed Central

Hänggi, Jürgen; Jancke, Lutz

2014-01-01

The perception of oneself as absorbed in the thoughts, feelings and happenings of a fictive character (e.g. in a novel or film) as if the character’s experiences were one’s own is referred to as identification. We investigated whether individual variation in the personality trait of identification is associated with individual variation in the structure of specific brain regions, using surface and volume-based morphometry. The hypothesized regions of interest were selected on the basis of their functional role in subserving the cognitive processing domains considered important for identification (i.e. mental imagery, empathy, theory of mind and merging) and for the immersive experience called ‘presence’. Controlling for age, sex, whole-brain volume and other traits, identification covaried significantly with the left hippocampal volume, cortical thickness in the right anterior insula and the left dorsal medial prefrontal cortex, and with gray matter volume in the dorsolateral prefrontal cortex. These findings show that trait identification is associated with structural variation in specific brain regions. The findings are discussed in relation to the potential functional contribution of these regions to identification. PMID:24464847

The effect of a period of intensive exercise on the isoform test to detect growth hormone doping in sports.

PubMed

Voss, S C; Giraud, S; Alsayrafi, M; Bourdon, P C; Schumacher, Y O; Saugy, M; Robinson, N

2013-08-01

The major objective of this study was to investigate the effects of several days of intense exercise on growth hormone (hGH) testing using the World Anti-Doping Agencies hGH isoform differential immunoassays. Additionally the effects of circadian variation and exercise type on the isoform ratios were also investigated. 15 male athletes performed a simulated nine day cycling stage race. Blood samples were collected twice daily over a period of 15 days (stage race+three days before and after). hGH isoforms were analysed by the official WADA immunoassays (CMZ Assay GmbH). All measured isoform ratios were far below the WADA decision limits for an adverse analytical finding. Changes in the isoform ratios could not be clearly connected to circadian variation, exercise duration or intensity. The present study demonstrates that the hGH isoform ratios are not significantly affected by exercise or circadian variation. We demonstrated that heavy, long term exercise does not interfere with the decision limits for an adverse analytical finding. Copyright © 2013 Elsevier Ltd. All rights reserved.

Atlantic salmon eggs favour sperm in competition that have similar major histocompatibility alleles.

PubMed

Yeates, Sarah E; Einum, Sigurd; Fleming, Ian A; Megens, Hendrik-Jan; Stet, René J M; Hindar, Kjetil; Holt, William V; Van Look, Katrien J W; Gage, Matthew J G

2009-02-07

Polyandry and post-copulatory sexual selection provide opportunities for the evolution of female differential sperm selection. Here, we examined the influence of variation in major histocompatibility (MH) class I allelic composition upon sperm competition dynamics in Atlantic salmon. We ran in vitro fertilization competitions that mimicked the gametic microenvironment, and replicated a paired-male experimental design that allowed us to compare differences in sperm competition success among males when their sperm compete for eggs from females that were genetically either similar or dissimilar at the MH class I locus. Concurrently, we measured variation in spermatozoal traits that are known to influence relative fertilization success under these conditions. Contrary to the findings demonstrating mechanisms that promote MH complex heterozygosity, our results showed that males won significantly greater relative fertilization success when competing for eggs from genetically similar females at the MH class I. This result also showed covariation with the known influences of sperm velocity on relative fertilization success. We discuss these unexpected findings in relation to sperm-egg recognition and hybridization avoidance mechanisms based upon immunogenetic variation.

Characterizing relative humidity with respect to ice in midlatitude cirrus clouds as a function of atmospheric state

NASA Astrophysics Data System (ADS)

Dzambo, Andrew M.; Turner, David D.

2016-10-01

Midlatitude cirrus cloud macrophysical and microphysical properties have been shown in previous studies to vary seasonally and in various large-scale dynamical regimes, but relative humidity with respect to ice (RHI) within cirrus clouds has not been studied extensively in this context. Using a combination of radiosonde and millimeter-wavelength cloud radar data, we identify 1076 cirrus clouds spanning a 7 year period from 2004 to 2011. These data are separated into five classes using a previously published algorithm that is based largely on synoptic conditions. Using these data and classification scheme, we find that RHI in cirrus clouds varies seasonally. Variations in cirrus cloud RHI exist within the prescribed classifications; however, most of the variations are within the measurement uncertainty. Additionally, with the exception of nonsummer class cirrus, these variations are not statistically significant. We also find that cirrus cloud occurrence is not necessarily correlated with higher observed values of RHI. The structure of RHI in cirrus clouds varies more in thicker clouds, which follows previous studies showing that macrophysical and microphysical variability increases in thicker cirrus clouds.

The Genetic Basis of Natural Variation in Caenorhabditis elegans Telomere Length.

PubMed

Cook, Daniel E; Zdraljevic, Stefan; Tanny, Robyn E; Seo, Beomseok; Riccardi, David D; Noble, Luke M; Rockman, Matthew V; Alkema, Mark J; Braendle, Christian; Kammenga, Jan E; Wang, John; Kruglyak, Leonid; Félix, Marie-Anne; Lee, Junho; Andersen, Erik C

2016-09-01

Telomeres are involved in the maintenance of chromosomes and the prevention of genome instability. Despite this central importance, significant variation in telomere length has been observed in a variety of organisms. The genetic determinants of telomere-length variation and their effects on organismal fitness are largely unexplored. Here, we describe natural variation in telomere length across the Caenorhabditis elegans species. We identify a large-effect variant that contributes to differences in telomere length. The variant alters the conserved oligonucleotide/oligosaccharide-binding fold of protection of telomeres 2 (POT-2), a homolog of a human telomere-capping shelterin complex subunit. Mutations within this domain likely reduce the ability of POT-2 to bind telomeric DNA, thereby increasing telomere length. We find that telomere-length variation does not correlate with offspring production or longevity in C. elegans wild isolates, suggesting that naturally long telomeres play a limited role in modifying fitness phenotypes in C. elegans. Copyright © 2016 by the Genetics Society of America.

Limited common origins of multiple adult health-related behaviors: Evidence from U.S. twins.

PubMed

Sudharsanan, Nikkil; Behrman, Jere R; Kohler, Hans-Peter

2016-12-01

Health-related behaviors are significant contributors to morbidity and mortality in the United States, yet evidence on the underlying causes of the vast within-population variation in behaviors is mixed. While many potential causes of health-related behaviors have been identified-such as schooling, genetics, and environments-little is known on how much of the variation across multiple behaviors is due to a common set of causes. We use three separate datasets on U.S. twins to investigate the degree to which multiple health-related behaviors correlate and can be explained by a common set of factors. We find that aside from smoking and drinking, most behaviors are not strongly correlated among individuals. Based on the results of both within-identical-twins regressions and multivariate behavioral genetics models, we find some evidence that schooling may be related to smoking but not to the covariation between multiple behaviors. Similarly, we find that a large fraction of the variance in each of the behaviors is consistent with genetic factors; however, we do not find strong evidence that a single common set of genes explains variation in multiple behaviors. We find, however, that a large portion of the correlation between smoking and heavy drinking is consistent with common, mostly childhood, environments. This suggests that the initiation and patterns of these two behaviors might arise from a common childhood origin. Research and policy to identify and modify this source may provide a strong way to reduce the population health burden of smoking and heavy drinking. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ontogenetic and diel variation in stream habitat use by brook trout (Salvelinus fontinalis) in a headwater stream

USGS Publications Warehouse

Johnson, J. H.; Ross, R.M.; Dropkin, D.S.; Redell, L.A.

2011-01-01

Although considerable information exists on habitat use by stream salmonids, only a small portion has quantitatively examined diurnal and nocturnal habitat variation. We examined diel variation in habitat use by age-0 and age-1+ brook trout (Salvelinus fontinalis) during summer and autumn in a headwater stream in northern Pennsylvania. Habitat variables measured included cover, depth, substrate, and velocity. The most pronounced diel variation occurred in the use of cover during both seasons. Both age-0 brook trout and age-1+ trout were associated with less cover at night. Age-0 brook trout occupied swifter water during the day than at night during both seasons, but the difference was not significant. Increased cover, depth, and substrate size governed the habitat of age-1+ brook trout. Our findings support the need for a better understanding of diel differences in habitat use of stream salmonids when considering habitat enhancement and protection.

Solar luminosity variations in solar cycle 21

NASA Technical Reports Server (NTRS)

Willson, Richard C.; Hudson, H. S.

1988-01-01

Long-term variations in the solar total irradiance found in the ACRIM I experiment on the SMM satellite have revealed a downward trend during the declining phase of solar cycle 21 of the sunspot cycle, a flat period between mid-1095 and mid-1987, and an upturn in late 1987 which suggests a direct correlation of luminosity and solar active region population. If the upturn continues into the activity maximum of solar cycle 22, a relation between solar activity and luminosity of possible climatological significance could be ascertained. The best-fit relationship for the variation of total irradiance S with sunspot number Rz and 10-cm flux F(10) are S = 1366.82 + 7.71 x 10 to the -3rd Rz and S = 1366.27 + 8.98 x 10 to the -3rd F(10)(W/sq m). These findings could be used to approximate total irradiance variations over the periods for which these indices have been compiled.

Performance variation in motor imagery brain-computer interface: a brief review.

PubMed

Ahn, Minkyu; Jun, Sung Chan

2015-03-30

Brain-computer interface (BCI) technology has attracted significant attention over recent decades, and has made remarkable progress. However, BCI still faces a critical hurdle, in that performance varies greatly across and even within subjects, an obstacle that degrades the reliability of BCI systems. Understanding the causes of these problems is important if we are to create more stable systems. In this short review, we report the most recent studies and findings on performance variation, especially in motor imagery-based BCI, which has found that low-performance groups have a less-developed brain network that is incapable of motor imagery. Further, psychological and physiological states influence performance variation within subjects. We propose a possible strategic approach to deal with this variation, which may contribute to improving the reliability of BCI. In addition, the limitations of current work and opportunities for future studies are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Integrative analysis of RNA, translation, and protein levels reveals distinct regulatory variation across humans

PubMed Central

Cenik, Can; Cenik, Elif Sarinay; Byeon, Gun W.; Grubert, Fabian; Candille, Sophie I.; Spacek, Damek; Alsallakh, Bilal; Tilgner, Hagen; Araya, Carlos L.; Tang, Hua; Ricci, Emiliano; Snyder, Michael P.

2015-01-01

Elucidating the consequences of genetic differences between humans is essential for understanding phenotypic diversity and personalized medicine. Although variation in RNA levels, transcription factor binding, and chromatin have been explored, little is known about global variation in translation and its genetic determinants. We used ribosome profiling, RNA sequencing, and mass spectrometry to perform an integrated analysis in lymphoblastoid cell lines from a diverse group of individuals. We find significant differences in RNA, translation, and protein levels suggesting diverse mechanisms of personalized gene expression control. Combined analysis of RNA expression and ribosome occupancy improves the identification of individual protein level differences. Finally, we identify genetic differences that specifically modulate ribosome occupancy—many of these differences lie close to start codons and upstream ORFs. Our results reveal a new level of gene expression variation among humans and indicate that genetic variants can cause changes in protein levels through effects on translation. PMID:26297486

Evaluation of the Importance of VlsE Antigenic Variation for the Enzootic Cycle of Borrelia burgdorferi.

PubMed

Rogovskyy, Artem S; Casselli, Timothy; Tourand, Yvonne; Jones, Cami R; Owen, Jeb P; Mason, Kathleen L; Scoles, Glen A; Bankhead, Troy

2015-01-01

Efficient acquisition and transmission of Borrelia burgdorferi by the tick vector, and the ability to persistently infect both vector and host, are important elements for the life cycle of the Lyme disease pathogen. Previous work has provided strong evidence implicating the significance of the vls locus for B. burgdorferi persistence. However, studies involving vls mutant clones have thus far only utilized in vitro-grown or host-adapted spirochetes and laboratory strains of mice. Additionally, the effects of vls mutation on tick acquisition and transmission has not yet been tested. Thus, the importance of VlsE antigenic variation for persistent infection of the natural reservoir host, and for the B. burgdorferi enzootic life cycle in general, has not been examined to date. In the current work, Ixodes scapularis and Peromyscus maniculatus were infected with different vls mutant clones to study the importance of the vls locus for the enzootic cycle of the Lyme disease pathogen. The findings highlight the significance of the vls system for long-term infection of the natural reservoir host, and show that VlsE antigenic variability is advantageous for efficient tick acquisition of B. burgdorferi from the mammalian reservoir. The data also indicate that the adaptation state of infecting spirochetes influences B. burgdorferi avoidance from host antibodies, which may be in part due to its respective VlsE expression levels. Overall, the current findings provide the most direct evidence on the importance of VlsE for the enzootic cycle of Lyme disease spirochetes, and underscore the significance of VlsE antigenic variation for maintaining B. burgdorferi in nature.

Moral values are associated with individual differences in regional brain volume

PubMed Central

Lewis, G. J.; Kanai, R.; Bates, T. C.; Rees, G.

2012-01-01

Moral sentiment has been hypothesized to reflect evolved adaptations to social living. If so, individual differences in moral values may relate to regional variation in brain structure. We tested this hypothesis in a sample of 70 young, healthy adults examining whether differences on two major dimensions of moral values were significantly associated with regional gray matter volume. The two clusters of moral values assessed were “individualizing” (values of harm/care and fairness), and “binding” (deference to authority, in-group loyalty, and purity/sanctity). Individualizing was positively associated with left dorsomedial prefrontal cortex volume, and negatively associated with bilateral precuneus volume. For binding, a significant positive association was found for bilateral subcallosal gyrus and a trend to significance for the left anterior insula volume. These findings demonstrate that variation in moral sentiment reflects individual differences in brain structure and suggest a biological basis for moral sentiment, distributed across multiple brain regions. PMID:22571458

Moral values are associated with individual differences in regional brain volume.

PubMed

Lewis, Gary J; Kanai, Ryota; Bates, Timothy C; Rees, Geraint

2012-08-01

Moral sentiment has been hypothesized to reflect evolved adaptations to social living. If so, individual differences in moral values may relate to regional variation in brain structure. We tested this hypothesis in a sample of 70 young, healthy adults examining whether differences on two major dimensions of moral values were significantly associated with regional gray matter volume. The two clusters of moral values assessed were "individualizing" (values of harm/care and fairness) and "binding" (deference to authority, in-group loyalty, and purity/sanctity). Individualizing was positively associated with left dorsomedial pFC volume and negatively associated with bilateral precuneus volume. For binding, a significant positive association was found for bilateral subcallosal gyrus and a trend to significance for the left anterior insula volume. These findings demonstrate that variation in moral sentiment reflects individual differences in brain structure and suggest a biological basis for moral sentiment, distributed across multiple brain regions.

A radar survey of M- and X-class asteroids

NASA Astrophysics Data System (ADS)

Shepard, Michael K.; Clark, Beth Ellen; Nolan, Michael C.; Howell, Ellen S.; Magri, Christopher; Giorgini, Jon D.; Benner, Lance A. M.; Ostro, Steven J.; Harris, Alan W.; Warner, Brian; Pray, Donald; Pravec, Petr; Fauerbach, Michael; Bennett, Thomas; Klotz, Alain; Behrend, Raoul; Correia, Horacio; Coloma, Josep; Casulli, Silvano; Rivkin, Andrew

2008-05-01

We observed ten M- and X-class main-belt asteroids with the Arecibo Observatory's S-band (12.6 cm) radar. The X-class asteroids were targeted based on their albedos or other properties which suggested they might be M-class. This work brings the total number of main-belt M-class asteroids observed with radar to 14. We find that three of these asteroids have rotation rates significantly different from what was previously reported. Based on their high radar albedo, we find that only four of the fourteen—16 Psyche, 216 Kleopatra, 758 Mancunia, and 785 Zwetana—are almost certainly metallic. 129 Antigone has a moderately high radar albedo and we suggest it may be a CH/CB/Bencubbinite parent body. Three other asteroids, 97 Klotho, 224 Oceana, and 796 Sarita have radar albedos significantly higher than the average main belt asteroid and we cannot rule out a significant metal content for them. Five of our target asteroids, 16 Psyche, 129 Antigone, 135 Hertha, 758 Mancunia, and 785 Zwetana, show variations in their radar albedo with rotation. We can rule out shape and composition in most cases, leaving variations in thickness, porosity, or surface roughness of the regolith to be the most likely causes. With the exception of 129 Antigone, we find no hydrated M-class asteroids (W-class; Rivkin, A.S., Howell, E.S., Lebofsky, L.A., Clark, B.E., Britt, D.T., 2000. Icarus 145, 351-368) to have high radar albedos.

Design and Test of an Instrument for Measuring Microthermal Seeing on the Magdalena Ridge

NASA Astrophysics Data System (ADS)

Jorgensen, A. M.; Klinglesmith, D. A., III; Speights, J.; Clements, A.; Patel, J.

2009-05-01

We have constructed and operated an automated instrument for measuring ground-level microthermal seeing at the Magdalena Ridge Observatory (MRO). The MRO is located at an altitude of 10500' in the Cibola National Forest in New Mexico, USA. It is the planned site for the MRO Optical Interferometer (MROI) planned for up to 10 collecting elements, each with a diameter of 1.4 m, and baselines eventually up to approximately 400 m. As part of the preparation for construction we deployed a system to characterize the ground-level seeing across the observatory site. The instrument is built largely of off-the-shelf components, with only the sensor head and power supply requiring electronic board assembly. Even in those cases the board architecture is very simple. The first proof-of-concept system was deployed for several weeks in the autumn of 2004, and has since undergone several iterations. The latest configuration operates entirely off batteries, incorporates wireless data acquisition, and is thus able to operate in an area with no shelter, power, or communications. In this paper we present the design of the instrument, and show initial data. The microthermal tower has four sensor pairs at heights from 0.8 to 4.41 m, significantly lower than other microthermal experiments, because of the need to characterize the seeing near the ground. We find significant variation in the contribution of this range of heights to the seeing, contributing up to 0farcs3 of the seeing at some times and only 0farcs02 at other times. The individual sensor power spectra have a slope in the range of 1.4--1.5, which is lower than the 1.67 slope predicted by Kolmogorov turbulence theory. We measure the well known effect of improved seeing immediately around sunset. While we find significant variation in the microthermal seeing, we did not find a pattern of corresponding variations in weather conditions, suggesting that a complicated set of factors control microthermal turbulence.

Diversification rates and species richness across the Tree of Life.

PubMed

Scholl, Joshua P; Wiens, John J

2016-09-14

Species richness varies dramatically among clades across the Tree of Life, by over a million-fold in some cases (e.g. placozoans versus arthropods). Two major explanations for differences in richness among clades are the clade-age hypothesis (i.e. species-rich clades are older) and the diversification-rate hypothesis (i.e. species-rich clades diversify more rapidly, where diversification rate is the net balance of speciation and extinction over time). Here, we examine patterns of variation in diversification rates across the Tree of Life. We address how rates vary across higher taxa, whether rates within higher taxa are related to the subclades within them, and how diversification rates of clades are related to their species richness. We find substantial variation in diversification rates, with rates in plants nearly twice as high as in animals, and rates in some eukaryotes approximately 10-fold faster than prokaryotes. Rates for each kingdom-level clade are then significantly related to the subclades within them. Although caution is needed when interpreting relationships between diversification rates and richness, a positive relationship between the two is not inevitable. We find that variation in diversification rates seems to explain most variation in richness among clades across the Tree of Life, in contrast to the conclusions of previous studies. © 2016 The Author(s).

Diversification rates and species richness across the Tree of Life

PubMed Central

Scholl, Joshua P.

2016-01-01

Species richness varies dramatically among clades across the Tree of Life, by over a million-fold in some cases (e.g. placozoans versus arthropods). Two major explanations for differences in richness among clades are the clade-age hypothesis (i.e. species-rich clades are older) and the diversification-rate hypothesis (i.e. species-rich clades diversify more rapidly, where diversification rate is the net balance of speciation and extinction over time). Here, we examine patterns of variation in diversification rates across the Tree of Life. We address how rates vary across higher taxa, whether rates within higher taxa are related to the subclades within them, and how diversification rates of clades are related to their species richness. We find substantial variation in diversification rates, with rates in plants nearly twice as high as in animals, and rates in some eukaryotes approximately 10-fold faster than prokaryotes. Rates for each kingdom-level clade are then significantly related to the subclades within them. Although caution is needed when interpreting relationships between diversification rates and richness, a positive relationship between the two is not inevitable. We find that variation in diversification rates seems to explain most variation in richness among clades across the Tree of Life, in contrast to the conclusions of previous studies. PMID:27605507

Three-Year Change in the Wellbeing of Orphaned and Separated Children in Institutional and Family-Based Care Settings in Five Low- and Middle-Income Countries

PubMed Central

Whetten, Kathryn; Ostermann, Jan; Pence, Brian W.; Whetten, Rachel A.; Messer, Lynne C.; Ariely, Sumedha; O'Donnell, Karen; Wasonga, Augustine I.; Vann, Vanroth; Itemba, Dafrosa; Eticha, Misganaw; Madan, Ira; Thielman, Nathan M.

2014-01-01

Background With more than 2 million children living in group homes, or “institutions”, worldwide, the extent to which institution-based caregiving negatively affects development and wellbeing is a central question for international policymakers. Methods A two-stage random sampling methodology identified community representative samples of 1,357 institution-dwelling orphaned and separated children (OSC) and 1,480 family-dwelling OSC aged 6–12 from 5 low and middle income countries. Data were collected from children and their primary caregivers. Survey-analytic techniques and linear mixed effects models describe child wellbeing collected at baseline and at 36 months, including physical and emotional health, growth, cognitive development and memory, and the variation in outcomes between children, care settings, and study sites. Findings At 36-month follow-up, institution-dwelling OSC had statistically significantly higher height-for-age Z-scores and better caregiver-reported physical health; family-dwelling OSC had fewer caregiver-reported emotional difficulties. There were no statistically significant differences between the two groups on other measures. At both baseline and follow-up, the magnitude of the differences between the institution- and family-dwelling groups was small. Relatively little variation in outcomes was attributable to differences between sites (11–27% of total variation) or care settings within sites (8–14%), with most variation attributable to differences between children within settings (60–75%). The percent of variation in outcomes attributable to the care setting type, institution- versus family-based care, ranged from 0–4% at baseline, 0–3% at 36-month follow-up, and 0–4% for changes between baseline and 36 months. Interpretation These findings contradict the hypothesis that group home placement universally adversely affects child wellbeing. Without substantial improvements in and support for family settings, the removal of institutions, broadly defined, would not significantly improve child wellbeing and could worsen outcomes of children who are moved from a setting where they are doing relatively well to a more deprived setting. PMID:25162410

Accounting for magnetic diffusion in core flow inversions from geomagnetic secular variation

NASA Astrophysics Data System (ADS)

Amit, Hagay; Christensen, Ulrich R.

2008-12-01

We use numerical dynamos to investigate the possible role of magnetic diffusion at the top of the core. We find that the contribution of radial magnetic diffusion to the secular variation is correlated with that of tangential magnetic diffusion for a wide range of control parameters. The correlation between the two diffusive terms is interpreted in terms of the variation in the strength of poloidal flow along a columnar flow tube. The amplitude ratio of the two diffusive terms is used to estimate the probable contribution of radial magnetic diffusion to the secular variation at Earth-like conditions. We then apply a model where radial magnetic diffusion is proportional to tangential diffusion to core flow inversions of geomagnetic secular variation data. We find that including magnetic diffusion does not change dramatically the global flow but some significant local variations appear. In the non frozen-flux core flow models (termed `diffusive'), the hemispherical dichotomy between the active Atlantic and quiet Pacific is weaker, a cyclonic vortex below North America emerges and the vortex below Asia is stronger. Our results have several important geophysical implications. First, our diffusive flow models contain some flow activity at low latitudes in the Pacific, suggesting a local balance between magnetic field advection and diffusion in that region. Second, the cyclone below North America in our diffusive flows reconciles the difference between mantle-driven thermal wind predictions and frozen-flux core flow models, and is consistent with the prominent intense magnetic flux patch below North America in geomagnetic field models. Finally, we hypothesize that magnetic diffusion near the core surface plays a larger role in the geomagnetic secular variation than usually assumed.

Does Circadian Variation of Mothers Affect Macronutrients of Breast Milk?

PubMed

Çetinkaya, Aslihan Köse; Dizdar, Evrim Alyamaç; Yarcı, Erbu; Sari, Fatma Nur; Oguz, Serife Suna; Uras, Nurdan; Canpolat, Fuat Emre

2017-06-01

Objective  To determine the within-day variation of fat, protein, and carbohydrate content of breast milk. Methods  The study was conducted at Zekai Tahir Burak Maternity Teaching Hospital between April 2013 and January 2014. We obtained milk samples from lactating mothers of hospitalized infants through hand expression after breast-feeding or pumping three times a day. A mid-infrared human milk analyzer was used for measuring the macronutrient contents of breast milk samples. Results  Lactating mothers of 52 infants (30 preterm, 22 term) were recruited to the study. No significant difference was found in protein, fat, and carbohydrate content of milk samples throughout the day. We compared within-day variation of macronutrients of transitional and mature milk, milk samples from the mothers of preterm and term infants, and samples collected by either hand expression or pumping. We did not find a significant difference between the groups. Conclusion  Absence of circadian variations in lipid, carbohydrate, and protein content of breast milk in our study may be related to ethnic differences, maternal nutritional status, different milk content measurement technique, and population characteristics. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Genetic factors of age-related macular degeneration

PubMed Central

Tuo, Jingsheng; Bojanowski, Christine M.; Chan, Chi-Chao

2007-01-01

Age-related macular degeneration (AMD) is a leading cause of blindness in the United States and developed countries. Although the etiology and pathogenesis of AMD remain unknown, a complex interaction of genetic and environmental factors is thought to exist. The incidence and progression of all of the features of AMD are known to increase significantly with age. The tendency for familial aggregation and the findings of gene variation association studies implicate a significant genetic component in the development of AMD. This review summarizes in detail the AMD-related genes identified by studies on genetically engineered and spontaneously gene-mutated (naturally mutated) animals, AMD chromosomal loci identified by linkage studies, AMD-related genes identified through studies of monogenic degenerative retinal diseases, and AMD-related gene variation identified by association studies. PMID:15094132

Unusual arterial pattern of the gastrointestinal tract: inferior mesenteric artery arising from the iliac artery and corkscrew external iliac.

PubMed

Nassar, Lara; Atweh, Lamya Ann; Jurjus, Abdo; Al Kutoubi, Aghiad

2012-07-01

Anatomical variations of the digestive system arteries are important due to their clinical significance. However, anomalies in the inferior mesenteric artery (IMA) are the least common compared with the celiac trunk and superior mesenteric artery. This report describes the case of a 67-year-old man with an extremely rare variant in which the IMA arises from the left common iliac artery, and the ipsilateral external iliac artery has a corkscrew pattern. These findings were depicted during computed tomography angiography of the abdomen and pelvis. This case is the first report of such a variation associated with a left external iliac artery turning into a double loop before forming the femoral artery. The embryological and clinical significance of such an anomaly are discussed.

Blood lipid measurements. Variations and practical utility.

PubMed

Cooper, G R; Myers, G L; Smith, S J; Schlant, R C

1992-03-25

To describe the magnitude and impact of the major biological and analytical sources of variation in serum lipid and lipoprotein levels on risk of coronary heart disease; to present a way to qualitatively estimate the total intraindividual variation; and to demonstrate how to determine the number of specimens required to estimate, with 95% confidence, the "true" underlying total cholesterol value in the serum of a patient. Representative references on each source of variation were selected from more than 300 reviewed publications, most published within the past 5 years, to document current findings and concepts. Most articles reviewed were in English. Studies on biological sources of variation were selected using the following criteria: representative of published findings, clear statement of either significant or insignificant results, and acquisition of clinical and laboratory data under standardized conditions. Representative results for special populations such as women and children are reported when results differ from those of adult men. References were selected based on acceptable experimental design and use of standardized laboratory lipid measurements. The lipid levels considered representative for a selected source of variation arose from quantitative measurements by a suitably standardized laboratory. Statistical analysis of data was examined to assure reliability. The proposed method of estimating the biological coefficient of variation must be considered to give qualitative results, because only two or three serial specimens are collected in most cases for the estimation. Concern has arisen about the magnitude, impact, and interpretation of preanalytical as well as analytical sources of variation on reported results of lipid measurements of an individual. Preanalytical sources of variation from behavioral, clinical, and sampling sources constitute about 60% of the total variation in a reported lipid measurement of an individual. A technique is presented to allow physicians to qualitatively estimate the intraindividual biological variation of a patient from the results of two or more specimens reported from a standardized laboratory and to determine whether additional specimens are needed to meet the National Cholesterol Education Program recommendation that the intraindividual serum total cholesterol coefficient of variation not exceed 5.0. A National Reference Method Network has been established to help solve analytical problems.

Determinants of unwanted pregnancies in India using matched case-control designs

PubMed Central

2012-01-01

Background In India, while the total fertility rate has been declined from 3.39 in 1992–93 to 2.68 in 2005–06, the prevalence of unintended pregnancy is still stagnant over the same period. A review of existing literature shows that within the country, there are variations in fertility preferences between different regions. Also there is a strong argument that the availability of a health facility at the village level plays an important role in reshaping the fertility behavior of women. Keeping in mind the fact that there is no information at the village level (which is the lowest geographical boundary) in the recent round of National Family Health Survey (NFHS-3), the specific objective of this study is to examine the impact of individual and household level variables on unwanted pregnancies without controlling the village level variation. Further, once the village level variation (i.e. unobserved variation) has been controlled, it is necessary to study whether there has been any alteration in the contribution of factors from earlier results of without adjusting the village level variation. Methods This paper attempts to examine the associated factors of unwanted pregnancies, without matching the village and after matching the village, by using the matched case–control design. Nationwide data from India’s latest NFHS-3 conducted during 2005–06 was used for the present study. Frequency and pair wise matching has been applied in the present paper and conditional logistic regression analysis was used to work out the models and to find out the factors associated with unwanted pregnancies. Results A major finding of this study was that 1:3 case–control study (without matching the village) shows that women belonging to non Hindu/Muslim religion, Scheduled Tribe, women who have experienced child loss and if the previous birth interval is 24 through 36 months were significant predictors of unwanted pregnancy. However, this relationship did not hold significant after village wise matching. Other factors such as Muslim religion, women and their partners with high school education and above, women belonging to the richest wealth index and if the sex of the last child was female, emerge as significant predictors of unwanted pregnancies. Conclusions This study clearly underscores the importance of adjusting the village (PSU) level variation in explaining unwanted pregnancies. PMID:22883933

Determinants of unwanted pregnancies in India using matched case-control designs.

PubMed

Dixit, Priyanka; Ram, Faujdar; Dwivedi, Laxmi Kant

2012-08-11

In India, while the total fertility rate has been declined from 3.39 in 1992-93 to 2.68 in 2005-06, the prevalence of unintended pregnancy is still stagnant over the same period. A review of existing literature shows that within the country, there are variations in fertility preferences between different regions. Also there is a strong argument that the availability of a health facility at the village level plays an important role in reshaping the fertility behavior of women. Keeping in mind the fact that there is no information at the village level (which is the lowest geographical boundary) in the recent round of National Family Health Survey (NFHS-3), the specific objective of this study is to examine the impact of individual and household level variables on unwanted pregnancies without controlling the village level variation. Further, once the village level variation (i.e. unobserved variation) has been controlled, it is necessary to study whether there has been any alteration in the contribution of factors from earlier results of without adjusting the village level variation. This paper attempts to examine the associated factors of unwanted pregnancies, without matching the village and after matching the village, by using the matched case-control design. Nationwide data from India's latest NFHS-3 conducted during 2005-06 was used for the present study. Frequency and pair wise matching has been applied in the present paper and conditional logistic regression analysis was used to work out the models and to find out the factors associated with unwanted pregnancies. A major finding of this study was that 1:3 case-control study (without matching the village) shows that women belonging to non Hindu/Muslim religion, Scheduled Tribe, women who have experienced child loss and if the previous birth interval is 24 through 36 months were significant predictors of unwanted pregnancy. However, this relationship did not hold significant after village wise matching. Other factors such as Muslim religion, women and their partners with high school education and above, women belonging to the richest wealth index and if the sex of the last child was female, emerge as significant predictors of unwanted pregnancies. This study clearly underscores the importance of adjusting the village (PSU) level variation in explaining unwanted pregnancies.

Variational symmetries, conserved quantities and identities for several equations of mathematical physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donchev, Veliko, E-mail: velikod@ie.bas.bg

2014-03-15

We find variational symmetries, conserved quantities and identities for several equations: envelope equation, Böcher equation, the propagation of sound waves with losses, flow of a gas with losses, and the nonlinear Schrödinger equation with losses or gains, and an electro-magnetic interaction. Most of these equations do not have a variational description with the classical variational principle and we find such a description with the generalized variational principle of Herglotz.

Testing the Relationships between Diversification, Species Richness, and Trait Evolution.

PubMed

Kozak, Kenneth H; Wiens, John J

2016-11-01

Understanding which traits drive species diversification is essential for macroevolutionary studies and to understand patterns of species richness among clades. An important tool for testing if traits influence diversification is to estimate rates of net diversification for each clade, and then test for a relationship between traits and diversification rates among clades. However, this general approach has become very controversial. Numerous papers have now stated that it is inappropriate to analyze net diversification rates in groups in which clade richness is not positively correlated with clade age. Similarly, some have stated that variation in net diversification rates does not explain variation in species richness patterns among clades across the Tree of Life. Some authors have also suggested that strong correlations between richness and diversification rates are a statistical artifact and effectively inevitable. If this latter point is true, then correlations between richness and diversification rates would be uninformative (or even misleading) for identifying how much variation in species richness among clades is explained by variation in net diversification rates. Here, we use simulations (based on empirical data for plethodontid salamanders) to address three main questions. First, how is variation in net diversification rates among clades related to the relationship between clade age and species richness? Second, how accurate are these net diversification rate estimators, and does the age-richness relationship have any relevance to their accuracy? Third, is a relationship between species richness and diversification rates an inevitable, statistical artifact? Our simulations show that strong, positive age-richness relationships arise when diversification rates are invariant among clades, whereas realistic variation in diversification rates among clades frequently disrupts this relationship. Thus, a significant age-richness relationship should not be a requirement for utilizing net diversification rates in macroevolutionary studies. Moreover, we find no difference in the accuracy of net diversification rate estimators between conditions in which there are strong, positive relationships between clade age and richness and conditions in which these strong relationships are absent. We find that net diversification rate estimators are reasonably accurate under many conditions (true and estimated rates are strongly corrrelated, and typically differ by ∼10-20%), but become more accurate when clades are older and less accurate when using incorrect assumptions about extinction. We also find that significant relationships between richness and diversification rates fail to arise under many conditions, especially when there are faster rates in younger clades. Therefore, a significant relationship between richness and diversification rates is not inevitable. Given this latter result, we suggest that relationships between richness and diversification should be tested for when attempting to explain the causes of richness patterns, to avoid potential misinterpretations (e.g., high diversification rates associated with low-richness clades). Similarly, our results also provide some support for previous studies suggesting that variation in diversification rates might explain much of the variation in species richness among major clades, based on strong relationships between clade richness and diversification rates. © The Author(s) 2016. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Does the Clock Make the Poison? Circadian Variation in Response to Pesticides

PubMed Central

Hooven, Louisa A.; Sherman, Katherine A.; Butcher, Shawn; Giebultowicz, Jadwiga M.

2009-01-01

Background Circadian clocks govern daily physiological and molecular rhythms, and putative rhythms in expression of xenobiotic metabolizing (XM) genes have been described in both insects and mammals. Such rhythms could have important consequences for outcomes of chemical exposures at different times of day. To determine whether reported XM gene expression rhythms result in functional rhythms, we examined daily profiles of enzyme activity and dose responses to the pesticides propoxur, deltamethrin, fipronil, and malathion. Methodology/Principal Findings Published microarray expression data were examined for temporal patterns. Male Drosophila were collected for ethoxycoumarin-O-deethylase (ECOD), esterase, glutathione-S-transferase (GST), and, and uridine 5′-diphosphoglucosyltransferase (UGT) enzyme activity assays, or subjected to dose-response tests at four hour intervals throughout the day in both light/dark and constant light conditions. Peak expression of several XM genes cluster in late afternoon. Significant diurnal variation was observed in ECOD and UGT enzyme activity, however, no significant daily variation was observed in esterase or GST activity. Daily profiles of susceptibility to lethality after acute exposure to propoxur and fipronil showed significantly increased resistance in midday, while susceptibility to deltamethrin and malathion varied little. In constant light, which interferes with clock function, the daily variation in susceptibility to propoxur and in ECOD and UGT enzyme activity was depressed. Conclusions/Significance Expression and activities of specific XM enzymes fluctuate during the day, and for specific insecticides, the concentration resulting in 50% mortality varies significantly during the day. Time of day of chemical exposure should be an important consideration in experimental design, use of pesticides, and human risk assessment. PMID:19649249

Nonlinear spherical perturbations in quintessence models of dark energy

NASA Astrophysics Data System (ADS)

Pratap Rajvanshi, Manvendra; Bagla, J. S.

2018-06-01

Observations have confirmed the accelerated expansion of the universe. The accelerated expansion can be modelled by invoking a cosmological constant or a dynamical model of dark energy. A key difference between these models is that the equation of state parameter w for dark energy differs from ‑1 in dynamical dark energy (DDE) models. Further, the equation of state parameter is not constant for a general DDE model. Such differences can be probed using the variation of scale factor with time by measuring distances. Another significant difference between the cosmological constant and DDE models is that the latter must cluster. Linear perturbation analysis indicates that perturbations in quintessence models of dark energy do not grow to have a significant amplitude at small length scales. In this paper we study the response of quintessence dark energy to non-linear perturbations in dark matter. We use a fully relativistic model for spherically symmetric perturbations. In this study we focus on thawing models. We find that in response to non-linear perturbations in dark matter, dark energy perturbations grow at a faster rate than expected in linear perturbation theory. We find that dark energy perturbation remains localised and does not diffuse out to larger scales. The dominant drivers of the evolution of dark energy perturbations are the local Hubble flow and a supression of gradients of the scalar field. We also find that the equation of state parameter w changes in response to perturbations in dark matter such that it also becomes a function of position. The variation of w in space is correlated with density contrast for matter. Variation of w and perturbations in dark energy are more pronounced in response to large scale perturbations in matter while the dependence on the amplitude of matter perturbations is much weaker.

Global markets and the differential effects of climate and weather on conflict

NASA Astrophysics Data System (ADS)

Meng, K. C.; Hsiang, S. M.; Cane, M. A.

2011-12-01

Both climate and weather have been attributed historically as possible drivers for violence. Previous empirical studies have either focused on isolating local idiosyncratic weather variation or have conflated weather with spatially coherent climatic changes. This paper provides the first study of the differential impacts of climate and weather variation by employing methods developed in earlier work linking the El Nino Southern Oscillation (ENSO) with the onset of civil conflicts. By separating the effects of climate from local weather, we are able to test possible mechanisms by which atmospheric changes can cause violence. It is generally difficult to separate the effect of year-to-year climate variations from other global events that might drive conflict. We avoid this problem by examining the set of tropical countries that are strongly teleconnected to ENSO. For this region, the ENSO cycle parallels the common year-to-year pattern of violence. Using ENSO, we isolate the influence of climatic changes from other global determinants of violence and compare it with the effect of local weather variations. We find that while climate affects the onset of civil conflicts in teleconnected countries, local weather has no significant effect. Productivity overall as well as across major sectors is more affected by local weather than by climatic variation. This is particularly evident in the agricultural sector where total value and cereal yield decline much greater from a 1°C increase in local temperature than a 1°C increase in ENSO. However, when examining the effect on food prices, we find that ENSO is associated with a large and statistically significant increase in cereal prices but no effect from hotter local temperatures. Altogether, this evidence points toward the ability of global and regional commodity markets to insure against the effects of local weather variation and their limitations in containing losses from aggregate shocks such as El Nino events. We posit that conflict reacts to climate and not weather because climatic events trigger not only local agricultural losses but also increased food prices as a result of an aggregate decline in output. This is because in an open economy, idiosyncratic weather variation alone would not lead to higher prices. These results are informative in understanding the impacts of anthropogenic global change, which would yield variation exhibiting spatial coherence beyond the extent of existing markets.

Impaired skeletal growth in mice with haploinsufficiency of IGF-I: genetic evidence that differences in IGF-I expression could contribute to peak bone mineral density differences

PubMed Central

Mohan, S; Baylink, D J

2010-01-01

Although it is well established that there is considerable inter-individual variation in the circulating levels of IGF-I in normal, healthy individuals and that a genetic component contributes substantially to this variation, the direct evidence that inter-individual variation in IGF-I contributes to differences in peak bone mineral density (BMD) is lacking. To examine if differences in IGF-I expression could contribute to peak BMD differences, we measured skeletal changes at days 23 (prepubertal), 31 (pubertal) and 56 (postpubertal) in mice with haploinsufficiency of IGF-I (+/−) and corresponding control mice (+/+). Mice (MF1/DBA) heterozygous for the IGF-I knockout allele were bred to generate +/+ and +/− mice (n=18–20 per group). Serum IGF-I was decreased by 23% (P<0·001) in mice with IGF-I haploinsufficiency (+/−) group at day 56 compared with the control (+/+) group. Femoral bone mineral content and BMD, as determined by dual energy X-ray absorptiometry, were reduced by 20% (P<0·001) and 12% respectively in the IGF-I (+/−) group at day 56 compared with the control group. The peripheral quantitative computed tomography measurements at the femoral mid-diaphysis revealed that periosteal circumference (7%, P<0·01) and total volumetric BMD (5%, P<0·05) were decreased significantly in the +/− group compared with the +/+ group. Furthermore, serum IGF-I showed significant positive correlations with both areal BMD (r=0·55) and periosteal circumference (r=0·66) in the pooled data from the +/+ and +/− groups. Our findings that haploinsufficiency of IGF-I caused significant reductions in serum IGF-I level, BMD and bone size, together with the previous findings, are consistent with the notion that genetic variations in IGF-I expression could, in part, contribute to inter-individual differences in peak BMD among a normal population. PMID:15930167

The Role of Copy Number Variation in Susceptibility to Amyotrophic Lateral Sclerosis: Genome-Wide Association Study and Comparison with Published Loci

PubMed Central

Wain, Louise V.; Pedroso, Inti; Landers, John E.; Breen, Gerome; Shaw, Christopher E.; Leigh, P. Nigel; Brown, Robert H.

2009-01-01

Background The genetic contribution to sporadic amyotrophic lateral sclerosis (ALS) has not been fully elucidated. There are increasing efforts to characterise the role of copy number variants (CNVs) in human diseases; two previous studies concluded that CNVs may influence risk of sporadic ALS, with multiple rare CNVs more important than common CNVs. A little-explored issue surrounding genome-wide CNV association studies is that of post-calling filtering and merging of raw CNV calls. We undertook simulations to define filter thresholds and considered optimal ways of merging overlapping CNV calls for association testing, taking into consideration possibly overlapping or nested, but distinct, CNVs and boundary estimation uncertainty. Methodology and Principal Findings In this study we screened Illumina 300K SNP genotyping data from 730 ALS cases and 789 controls for copy number variation. Following quality control filters using thresholds defined by simulation, a total of 11321 CNV calls were made across 575 cases and 621 controls. Using region-based and gene-based association analyses, we identified several loci showing nominally significant association. However, the choice of criteria for combining calls for association testing has an impact on the ranking of the results by their significance. Several loci which were previously reported as being associated with ALS were identified here. However, of another 15 genes previously reported as exhibiting ALS-specific copy number variation, only four exhibited copy number variation in this study. Potentially interesting novel loci, including EEF1D, a translation elongation factor involved in the delivery of aminoacyl tRNAs to the ribosome (a process which has previously been implicated in genetic studies of spinal muscular atrophy) were identified but must be treated with caution due to concerns surrounding genomic location and platform suitability. Conclusions and Significance Interpretation of CNV association findings must take into account the effects of filtering and combining CNV calls when based on early genome-wide genotyping platforms and modest study sizes. PMID:19997636

Vanadium isotope heterogeneity of the early solar system

NASA Astrophysics Data System (ADS)

Nielsen, S.; Auro, M. E. E.; Magna, T.; Davis, D. M.; Mezger, K.; Sarafian, A. R.

2017-12-01

Vanadium (V) has two isotopes with masses 50 and 51 that have 51V/50V ratio of 410. This ratio can be modified by production of 50V through cosmic irradiation, heterogeneous distribution of anomalous nucleosynthetic material and stable isotope fractionation. Due to the existence of only two V isotopes in nature, these latter processes cannot directly be distinguished from irradiation processes. Previous data has suggested that Earth is characterized by 51V/50V that is significantly different to that of meteorites. These data are difficult to reconcile with a singular process that caused the V isotope variation in the early Solar System. Here we present new V isotope data for a large range of meteorites in order to investigate the ultimate origin of V isotope variation in the early Solar System. We find limited and non-systematic 51V/50V variation of 0.3‰ for 25 martian meteorites (depleted/intermediate/enriched shergottites, nakhlites, and chassignite and orthopyroxenite ALH 84001), which suggests that igneous processes on Mars did not induce significant V isotope shifts. Our best estimate for V isotope composition of the bulk silicate Mars can thus be approximated by the mean value of the entire Martian meteorite suite. This value is significantly lighter ( 0.4‰) than that measured for pristine terrestrial rocks. In contrast, meteorites from the HED parent body reveal significant 51V/50V variation that may be linked to magmatic processes such as fractional crystallization of Vestan magma ocean. The two data sets illustrate that several processes are likely to explain the V isotope variation found in meteorites. We will also present new V isotope data for carbonaceous and ordinary chondrites and put them in the context of the values found for Earth, Mars and the HED parent body.

Effective variations of peer instruction: The effects of peer discussions, committing to an answer, and reaching a consensus

NASA Astrophysics Data System (ADS)

Lasry, Nathaniel; Charles, Elizabeth; Whittaker, Chris

2016-08-01

Peer Instruction (PI) is a widely used student-centered pedagogy, but one that is used differently by different instructors. While all PI instructors survey their students with conceptual questions, some do not allow students to discuss with peers. We studied the effect of peer discussion by polling three groups of students (N = 86) twice on the same set of nine conceptual questions. The three groups differed in the tasks assigned between the first and second poll: the first group discussed, the second reflected in silence, and the third was distracted so they could neither reflect nor discuss. Comparing score changes between the first and second poll, we find minimal increases in the distraction condition (3%), sizable increases in the reflection condition (10%), and significantly larger increases in the peer discussion condition (21%). We also examined the effect of committing to an answer before peer discussion and reaching a consensus afterward. We compared a lecture-based control section to three variations of PI that differed in their requirement to commit to an answer or reach consensus (N = 108). We find that all PI groups achieve greater conceptual learning and traditional problem solving than lecture-based instruction. We find one difference between these groups: the absence of consensus building is related to a significant decrease in expert views and beliefs. Our findings can therefore be used to make two recommendations: always use peer discussions and consider asking students to reach a consensus before re-polling.

Performance monitoring and error significance in patients with obsessive-compulsive disorder.

PubMed

Endrass, Tanja; Schuermann, Beate; Kaufmann, Christan; Spielberg, Rüdiger; Kniesche, Rainer; Kathmann, Norbert

2010-05-01

Performance monitoring has been consistently found to be overactive in obsessive-compulsive disorder (OCD). The present study examines whether performance monitoring in OCD is adjusted with error significance. Therefore, errors in a flanker task were followed by neutral (standard condition) or punishment feedbacks (punishment condition). In the standard condition patients had significantly larger error-related negativity (ERN) and correct-related negativity (CRN) ampliudes than controls. But, in the punishment condition groups did not differ in ERN and CRN amplitudes. While healthy controls showed an amplitude enhancement between standard and punishment condition, OCD patients showed no variation. In contrast, group differences were not found for the error positivity (Pe): both groups had larger Pe amplitudes in the punishment condition. Results confirm earlier findings of overactive error monitoring in OCD. The absence of a variation with error significance might indicate that OCD patients are unable to down-regulate their monitoring activity according to external requirements. Copyright 2010 Elsevier B.V. All rights reserved.

Analysis of Skin Humidity Variation Between Sasang Types

PubMed Central

Jung, Soon-Oh; Park, Soo-Jin; Chae, Han; Park, Soo Hyun; Hwang, Minwoo; Kim, Sang-Hyuk

2009-01-01

The purpose of this study was to examine the relationship between variations in skin humidity (SH) induced by perspiration across Sasang types and to identify novel and effective Sasang classification factors. We also analyzed the responses of each Sasang type to sweating-related QSCC II items. The results revealed a significant difference in SH across gender and significant differences in SH before and after perspiration between Tae-Eum and So-Eum men. In addition, Tae-Eum women showed significant differences in SH compared with women classified as another Sasang type. Furthermore, evaluation of the items related to sweating in the QSCC II and their relationship to each constitution revealed a significant difference between Tae-Eum and other Sasang types. Overall, the results of this study indicate that there is a distinct SH difference following perspiration between Tae-Eum and other Sasang types. Such findings may aid in Sasang typology diagnostic testing with the support of further sophisticated clinical studies. PMID:19745016

NNLO corrections to top pair production at hadron colliders: the quark-gluon reaction

NASA Astrophysics Data System (ADS)

Czakon, Michal; Mitov, Alexander

2013-01-01

We compute the next-to-next-to-leading order QCD correction to the total inclusive top pair production cross-section in the reaction qgto toverline{t}+X . We find moderate {O} (1%) correction to central values at both Tevatron and LHC. The scale variation of the cross-section remains unchanged at the Tevatron and is significantly reduced at the LHC. We find that recently introduced approximation based on the high-energy limit of the top pair cross-section significantly deviates from the exact result. The results derived in the present work are included in version 1.4 of the program Top++. Work towards computing the reaction ggto toverline{t}+X is ongoing.

Individual Differences in AMY1 Gene Copy Number, Salivary α-Amylase Levels, and the Perception of Oral Starch

PubMed Central

Mandel, Abigail L.; Peyrot des Gachons, Catherine; Plank, Kimberly L.; Alarcon, Suzanne; Breslin, Paul A. S.

2010-01-01

Background The digestion of dietary starch in humans is initiated by salivary α-amylase, an endo-enzyme that hydrolyzes starch into maltose, maltotriose and larger oligosaccharides. Salivary amylase accounts for 40 to 50% of protein in human saliva and rapidly alters the physical properties of starch. Importantly, the quantity and enzymatic activity of salivary amylase show significant individual variation. However, linking variation in salivary amylase levels with the oral perception of starch has proven difficult. Furthermore, the relationship between copy number variations (CNVs) in the AMY1 gene, which influence salivary amylase levels, and starch viscosity perception has not been explored. Principal Findings Here we demonstrate that saliva containing high levels of amylase has sufficient activity to rapidly hydrolyze a viscous starch solution in vitro. Furthermore, we show with time-intensity ratings, which track the digestion of starch during oral manipulation, that individuals with high amylase levels report faster and more significant decreases in perceived starch viscosity than people with low salivary amylase levels. Finally, we demonstrate that AMY1 CNVs predict an individual's amount and activity of salivary amylase and thereby, ultimately determine their perceived rate of oral starch viscosity thinning. Conclusions By linking genetic variation and its consequent salivary enzymatic differences to the perceptual sequellae of these variations, we show that AMY1 copy number relates to salivary amylase concentration and enzymatic activity level, which, in turn, account for individual variation in the oral perception of starch viscosity. The profound individual differences in salivary amylase levels and salivary activity may contribute significantly to individual differences in dietary starch intake and, consequently, to overall nutritional status. PMID:20967220

Neocortex expansion is linked to size variations in gene families with chemotaxis, cell-cell signalling and immune response functions in mammals.

PubMed

Castillo-Morales, Atahualpa; Monzón-Sandoval, Jimena; de Sousa, Alexandra A; Urrutia, Araxi O; Gutierrez, Humberto

2016-10-01

Increased brain size is thought to have played an important role in the evolution of mammals and is a highly variable trait across lineages. Variations in brain size are closely linked to corresponding variations in the size of the neocortex, a distinct mammalian evolutionary innovation. The genomic features that explain and/or accompany variations in the relative size of the neocortex remain unknown. By comparing the genomes of 28 mammalian species, we show that neocortical expansion relative to the rest of the brain is associated with variations in gene family size (GFS) of gene families that are significantly enriched in biological functions associated with chemotaxis, cell-cell signalling and immune response. Importantly, we find that previously reported GFS variations associated with increased brain size are largely accounted for by the stronger link between neocortex expansion and variations in the size of gene families. Moreover, genes within these families are more prominently expressed in the human neocortex during early compared with adult development. These results suggest that changes in GFS underlie morphological adaptations during brain evolution in mammalian lineages. © 2016 The Authors.

Neocortex expansion is linked to size variations in gene families with chemotaxis, cell–cell signalling and immune response functions in mammals

PubMed Central

Castillo-Morales, Atahualpa; Monzón-Sandoval, Jimena; de Sousa, Alexandra A.

2016-01-01

Increased brain size is thought to have played an important role in the evolution of mammals and is a highly variable trait across lineages. Variations in brain size are closely linked to corresponding variations in the size of the neocortex, a distinct mammalian evolutionary innovation. The genomic features that explain and/or accompany variations in the relative size of the neocortex remain unknown. By comparing the genomes of 28 mammalian species, we show that neocortical expansion relative to the rest of the brain is associated with variations in gene family size (GFS) of gene families that are significantly enriched in biological functions associated with chemotaxis, cell–cell signalling and immune response. Importantly, we find that previously reported GFS variations associated with increased brain size are largely accounted for by the stronger link between neocortex expansion and variations in the size of gene families. Moreover, genes within these families are more prominently expressed in the human neocortex during early compared with adult development. These results suggest that changes in GFS underlie morphological adaptations during brain evolution in mammalian lineages. PMID:27707894

Adult preferences for infantile facial features: an ethological approach.

PubMed

Sternglanz, S H; Gray, J L; Murakami, M

1977-02-01

In 1943 Konrad Lorenz postulated that certain infantile cues served as releasers for caretaking behaviour in human adults. This study is an attempt to confirm this hypothesis and to identify relevant cues. The stimuli studied were variations in facial features, and the responses were ratings of the attractiveness of the resultant infant faces. Parametric variations of eye height, eye width, eye height and width, iris size, and vertical variations in feature position (all presented in full-face drawings) were tested for their effect on the ratings, and highly significant preferences for particular stimuli were found. In general these preferences are consistent across a wide variety of environmental factors such as social class and experience with children. These findings are consistent with an ethological interpretation of the data.

Spatio-temporal Patterns of Vegetation and Its Relationship with Precipitation and Temperature in the Yarlung Zangbo River Basin, China

NASA Astrophysics Data System (ADS)

LIU, X.; Xu, Z.; Peng, D.

2017-12-01

Vegetation growth plays a significant role on runoff variation at high altitude, and precipitation and temperature are both key factors affecting vegetation conditions. As one of the greatest international rivers in China, the Yarlung Zangbo River in the southern Qinghai-Tibetan Plateau was selected, and the spatio-temporal patterns of vegetation were analyzed by using NDVI (Normalized Difference Vegetation Index) during 1998 2014. The relationship between NDVI and precipitation as well as temperature was also investigated in this study. Results showed that the value of NDVI increases with the decrease of elevation and the largest value appears in the broadleaf forest cover. Almost all annual NDVI variations exhibit an increasing tendency, particularly for the broadleaf forest cover. On the viewpoint of statistics, only 29% pixels of NDVI with increasing tendency are of significance for the other cover, while for cultivated vegetation cover, around 82% pixels of NDVI were detected with significant increasing tendency. In addition, vegetation growth showed lagging response to precipitation, and the lag time is around one month. Moreover, in the region with elevation over 5000 m, negative relationship between NDVI and precipitation for alpine vegetation was found. Approximately 75% of NDVI variations are dominated by precipitation and temperature. These findings may provide a reference to investigate runoff variations and strengthen ecological protection for similar high-altitude areas in the future.

Microclimatic variation in UV perception and related disparity in tropane and quinolizidine alkaloid composition of Atropa acuminata, Lupinus polyphyllus and Hyoscyamus niger.

PubMed

Jan, Sumira; Kamili, Azra N; Parray, Javid A; Bedi, Yashbir S; Ahmad, Parvaiz

2016-08-01

The aim of current research was to evaluate the physiological adjustment in three medicinal herbs viz., Atropa acuminata, Lupinus polyphyllus and Hyoscyamus niger to the winter period characterised by intense UV flux in Kashmir valley across the North Western Himalaya. Quinolizidine (QA) and tropane alkaloid (TA) concentrations were analysed in these herbs thriving at two different altitudes via GC-MS and correlated by PCA analysis. This study investigated the hypothesis that UV reflectance and absorbance at low temperatures are directly related to disparity in alkaloid accumulation. Among QAs in L. polyphyllus, ammodendrine and lupanine accumulated at higher concentration and exhibited significant variation of 186.36% and 95.91% in ammodendrine and lupanine respectively in both sites. Tetrahydrohombifoline displayed non-significant variation of about 9.60% irrespective of sites. Among tropane alkaloid (TA), hyoscyamine was recorded as the most abundant constituent irrespective of the plant and site while apotropine accumulated in lesser quantity in A. acuminata than H. niger. However, apotropine demonstrated significant variation of 175% among both sites. The final concentration of quinolizidine (QA) and tropane alkaloid (TA) reflects the interplay between reflectance and absorbance of UV radiation response field. These findings suggest that spectral response of UV light contributes directly to alkaloid biosynthesis. Copyright © 2016 Elsevier B.V. All rights reserved.

Electromyography-based analysis of human upper limbs during 45-day head-down bed-rest

NASA Astrophysics Data System (ADS)

Fu, Anshuang; Wang, Chunhui; Qi, Hongzhi; Li, Fan; Wang, Zheng; He, Feng; Zhou, Peng; Chen, Shanguang; Ming, Dong

2016-03-01

Muscle deconditioning occurs in response to simulated or actual microgravity. In spaceflight, astronauts become monkey-like for mainly using their upper limbs to control the operating system and to complete corresponding tasks. The changes of upper limbs' athletic ability will directly affect astronauts' working performance. This study investigated the variation trend of surface electromyography (sEMG) during prolonged simulated microgravity. Eight healthy males participating in this study performed strict 45-day head-down bed-rest (HDBR). On the 5th day of pre-HDBR, and the 15th, the 30th and the 45th days of HDBR, the subjects performed maximum pushing task and maximum pulling task, and sEMG was collected from upper limbs synchronously. Each subject's maximum volunteer contractions of both the tasks during these days were compared, showing no significant change. However, changes were detected by sEMG-based analysis. It was found that integrated EMG, root mean square, mean frequency, fuzzy entropy of deltoid, and fuzzy entropy of triceps brachii changed significantly when comparing pre-HDBR with HDBR. The variation trend showed a recovery tendency after significant decline, which is inconsistent with the monotonic variation of lower limbs that was proved by previous research. These findings suggest that EMG changes in upper limbs during prolonged simulated microgravity, but has different variation trend from lower limbs.

Space-based Coronagraphic Imaging Polarimetry of the TW Hydrae Disk: Shedding New Light on Self-shadowing Effects

NASA Astrophysics Data System (ADS)

Poteet, Charles A.; Chen, Christine H.; Hines, Dean C.; Perrin, Marshall D.; Debes, John H.; Pueyo, Laurent; Schneider, Glenn; Mazoyer, Johan; Kolokolova, Ludmilla

2018-06-01

We present Hubble Space Telescope Near-Infrared Camera and Multi-Object Spectrometer coronagraphic imaging polarimetry of the TW Hydrae protoplanetary disk. These observations simultaneously measure the total and polarized intensity, allowing direct measurement of the polarization fraction across the disk. In accord with the self-shadowing hypothesis recently proposed by Debes et al., we find that the total and polarized intensity of the disk exhibits strong azimuthal asymmetries at projected distances consistent with the previously reported bright and dark ring-shaped structures (∼45–99 au). The sinusoidal-like variations possess a maximum brightness at position angles near ∼268°–300° and are up to ∼28% stronger in total intensity. Furthermore, significant radial and azimuthal variations are also detected in the polarization fraction of the disk. In particular, we find that regions of lower polarization fraction are associated with annuli of increased surface brightness, suggesting that the relative proportion of multiple-to-single scattering is greater along the ring and gap structures. Moreover, we find strong (∼20%) azimuthal variation in the polarization fraction along the shadowed region of the disk. Further investigation reveals that the azimuthal variation is not the result of disk flaring effects, but is instead from a decrease in the relative contribution of multiple-to-single scattering within the shadowed region. Employing a two-layer scattering surface, we hypothesize that the diminished contribution in multiple scattering may result from shadowing by an inclined inner disk, which prevents direct stellar light from reaching the optically thick underlying surface component.

The Association between Arithmetic and Reading Performance in School: A Meta-Analytic Study

ERIC Educational Resources Information Center

Singer, Vivian; Strasser, Kathernie

2017-01-01

Many studies of school achievement find a significant association between reading and arithmetic achievement. The magnitude of the association varies widely across the studies, but the sources of this variation have not been identified. The purpose of this paper is to examine the magnitude and determinants of the relation between arithmetic and…

The color of sea level: Importance of spatial variations in spectral shape for assessing the significance of trends

NASA Astrophysics Data System (ADS)

Hughes, Chris W.; Williams, Simon D. P.

2010-10-01

We investigate spatial variations in the shape of the spectrum of sea level variability based on a homogeneously sampled 12 year gridded altimeter data set. We present a method of plotting spectral information as color, focusing on periods between 2 and 24 weeks, which shows that significant spatial variations in the spectral shape exist and contain useful dynamical information. Using the Bayesian Information Criterion, we determine that, typically, a fifth-order autoregressive model is needed to capture the structure in the spectrum. Using this model, we show that statistical errors in fitted local trends range between less than 1 and more than 5 times of what would be calculated assuming "white" noise and that the time needed to detect a 1 mm/yr trend ranges between about 5 years and many decades. For global mean sea level, the statistical error reduces to 0.1 mm/yr over 12 years, with only 2 years needed to detect a 1 mm/yr trend. We find significant regional differences in trend from the global mean. The patterns of these regional differences are indicative of a sea level trend dominated by dynamical ocean processes over this period.

Associations between Dopamine D4 Receptor Gene Variation with Both Infidelity and Sexual Promiscuity

PubMed Central

Garcia, Justin R.; MacKillop, James; Aller, Edward L.; Merriwether, Ann M.; Wilson, David Sloan; Lum, J. Koji

2010-01-01

Background Human sexual behavior is highly variable both within and between populations. While sex-related characteristics and sexual behavior are central to evolutionary theory (sexual selection), little is known about the genetic bases of individual variation in sexual behavior. The variable number tandem repeats (VNTR) polymorphism in exon III of the human dopamine D4 receptor gene (DRD4) has been correlated with an array of behavioral phenotypes and may be predicatively responsible for variation in motivating some sexual behaviors, particularly promiscuity and infidelity. Methodology/Principal Findings We administered an anonymous survey on personal history of sexual behavior and intimate relationships to 181 young adults. We also collected buccal wash samples and genotyped the DRD4 VNTR. Here we show that individuals with at least one 7-repeat allele (7R+) report a greater categorical rate of promiscuous sexual behavior (i.e., having ever had a “one-night stand”) and report a more than 50% increase in instances of sexual infidelity. Conclusions/Significance DRD4 VNTR genotype varies considerably within and among populations and has been subject to relatively recent, local selective pressures. Individual differences in sexual behavior are likely partially mediated by individual genetic variation in genes coding for motivation and reward in the brain. Conceptualizing these findings in terms of r/K selection theory suggests a mechanism for selective pressure for and against the 7R+ genotype that may explain the considerable global allelic variation for this polymorphism. PMID:21152404

Human difference in the genomic era: Facilitating a socially responsible dialogue

PubMed Central

2010-01-01

Background The study of human genetic variation has been advanced by research such as genome-wide association studies, which aim to identify variants associated with common, complex diseases and traits. Significant strides have already been made in gleaning information on susceptibility, treatment, and prevention of a number of disorders. However, as genetic researchers continue to uncover underlying differences between individuals, there is growing concern that observed population-level differences will be inappropriately generalized as inherent to particular racial or ethnic groups and potentially perpetuate negative stereotypes. Discussion We caution that imprecision of language when conveying research conclusions, compounded by the potential distortion of findings by the media, can lead to the stigmatization of racial and ethnic groups. Summary It is essential that the scientific community and with those reporting and disseminating research findings continue to foster a socially responsible dialogue about genetic variation and human difference. PMID:20504336

Variations in wounding by relationship intimacy in homicide cases.

PubMed

Trojan, Carrie; Krull, Amy C

2012-09-01

There are numerous examples in the homicide literature of a presumed connection between the victim-offender relationship and the manner, extent, and body location of wounds inflicted in homicides. The current study examined variations in wounding patterns according to the intimacy of the victim-offender relationship in a sample of urban homicides to explore the investigative utility of this information in an average homicide event. The findings demonstrated that victims who had a current or former intimate relationship with their offender were more likely to receive wounds to the face and be injured with a weapon from the scene compared with all other relationship groups, whereas injury to the head and use of manual violence were more likely among intimates and family/friends compared with acquaintances or strangers. However, the groups did not significantly differ in terms of the overall amount of wounds inflicted. Implications of the findings and suggested areas of future research are discussed.

MHC variation sculpts individualized microbial communities that control susceptibility to enteric infection

PubMed Central

Kubinak, Jason L.; Stephens, W. Zac; Soto, Ray; Petersen, Charisse; Chiaro, Tyson; Gogokhia, Lasha; Bell, Rickesha; Ajami, Nadim J.; Petrosino, Joseph F.; Morrison, Linda; Potts, Wayne K.; Jensen, Peter E.; O'Connell, Ryan M.; Round, June L.

2015-01-01

The presentation of protein antigens on the cell surface by major histocompatibility complex (MHC) molecules coordinates vertebrate adaptive immune responses, thereby mediating susceptibility to a variety of autoimmune and infectious diseases. The composition of symbiotic microbial communities (the microbiota) is influenced by host immunity and can have a profound impact on host physiology. Here we use an MHC congenic mouse model to test the hypothesis that genetic variation at MHC genes among individuals mediates susceptibility to disease by controlling microbiota composition. We find that MHC genotype significantly influences antibody responses against commensals in the gut, and that these responses are correlated with the establishment of unique microbial communities. Transplantation experiments in germfree mice indicate that MHC-mediated differences in microbiota composition are sufficient to explain susceptibility to enteric infection. Our findings indicate that MHC polymorphisms contribute to defining an individual's unique microbial fingerprint that influences health. PMID:26494419

Further Constraints on Variations in the Initial Mass Function from Low-mass X-ray Binary Populations

NASA Astrophysics Data System (ADS)

Peacock, Mark B.; Zepf, Stephen E.; Kundu, Arunav; Maccarone, Thomas J.; Lehmer, Bret D.; Maraston, Claudia; Gonzalez, Anthony H.; Eufrasio, Rafael T.; Coulter, David A.

2017-05-01

We present constraints on variations in the initial mass function (IMF) of nine local early-type galaxies based on their low-mass X-ray binary (LMXB) populations. Comprised of accreting black holes and neutron stars, these LMXBs can be used to constrain the important high-mass end of the IMF. We consider LMXB populations beyond the cores of the galaxies (>0.2R e; covering 75%-90% of their stellar light) and find no evidence for systematic variations of the IMF with velocity dispersion (σ). We reject IMFs which become increasingly bottom-heavy with σ, up to steep power laws (exponent, α > 2.8) in massive galaxies (σ > 300 {km} {{{s}}}-1), for galactocentric radii >1/4 R e. Previously proposed IMFs that become increasingly bottom-heavy with σ are consistent with these data if only the number of low-mass stars (<0.5 M ⊙) varies. We note that our results are consistent with some recent work which proposes that extreme IMFs are only present in the central regions of these galaxies. We also consider IMFs that become increasingly top-heavy with σ, resulting in significantly more LMXBs. Such a model is consistent with these observations, but additional data are required to significantly distinguish between this and an invariant IMF. For six of these galaxies, we directly compare with published “IMF mismatch” parameters from the Atlas3D survey, α dyn. We find good agreement with the LMXB population if galaxies with higher α dyn have more top-heavy IMFs—although we caution that our sample is quite small. Future LMXB observations can provide further insights into the origin of α dyn variations.

Pan-Tropical Analysis of Climate Effects on Seasonal Tree Growth

PubMed Central

Wagner, Fabien; Rossi, Vivien; Aubry-Kientz, Mélaine; Bonal, Damien; Dalitz, Helmut; Gliniars, Robert; Stahl, Clément; Trabucco, Antonio; Hérault, Bruno

2014-01-01

Climate models predict a range of changes in tropical forest regions, including increased average temperatures, decreased total precipitation, reduced soil moisture and alterations in seasonal climate variations. These changes are directly related to the increase in anthropogenic greenhouse gas concentrations, primarily CO2. Assessing seasonal forest growth responses to climate is of utmost importance because woody tissues, produced by photosynthesis from atmospheric CO2, water and light, constitute the main component of carbon sequestration in the forest ecosystem. In this paper, we combine intra-annual tree growth measurements from published tree growth data and the corresponding monthly climate data for 25 pan-tropical forest sites. This meta-analysis is designed to find the shared climate drivers of tree growth and their relative importance across pan-tropical forests in order to improve carbon uptake models in a global change context. Tree growth reveals significant intra-annual seasonality at seasonally dry sites or in wet tropical forests. Of the overall variation in tree growth, 28.7% was explained by the site effect, i.e. the tree growth average per site. The best predictive model included four climate variables: precipitation, solar radiation (estimated with extrasolar radiation reaching the atmosphere), temperature amplitude and relative soil water content. This model explained more than 50% of the tree growth variations across tropical forests. Precipitation and solar radiation are the main seasonal drivers of tree growth, causing 19.8% and 16.3% of the tree growth variations. Both have a significant positive association with tree growth. These findings suggest that forest productivity due to tropical tree growth will be reduced in the future if climate extremes, such as droughts, become more frequent. PMID:24670981

Pan-tropical analysis of climate effects on seasonal tree growth.

PubMed

Wagner, Fabien; Rossi, Vivien; Aubry-Kientz, Mélaine; Bonal, Damien; Dalitz, Helmut; Gliniars, Robert; Stahl, Clément; Trabucco, Antonio; Hérault, Bruno

2014-01-01

Climate models predict a range of changes in tropical forest regions, including increased average temperatures, decreased total precipitation, reduced soil moisture and alterations in seasonal climate variations. These changes are directly related to the increase in anthropogenic greenhouse gas concentrations, primarily CO2. Assessing seasonal forest growth responses to climate is of utmost importance because woody tissues, produced by photosynthesis from atmospheric CO2, water and light, constitute the main component of carbon sequestration in the forest ecosystem. In this paper, we combine intra-annual tree growth measurements from published tree growth data and the corresponding monthly climate data for 25 pan-tropical forest sites. This meta-analysis is designed to find the shared climate drivers of tree growth and their relative importance across pan-tropical forests in order to improve carbon uptake models in a global change context. Tree growth reveals significant intra-annual seasonality at seasonally dry sites or in wet tropical forests. Of the overall variation in tree growth, 28.7% was explained by the site effect, i.e. the tree growth average per site. The best predictive model included four climate variables: precipitation, solar radiation (estimated with extrasolar radiation reaching the atmosphere), temperature amplitude and relative soil water content. This model explained more than 50% of the tree growth variations across tropical forests. Precipitation and solar radiation are the main seasonal drivers of tree growth, causing 19.8% and 16.3% of the tree growth variations. Both have a significant positive association with tree growth. These findings suggest that forest productivity due to tropical tree growth will be reduced in the future if climate extremes, such as droughts, become more frequent.

Variation of Greenness across China's Universities: Motivations and Resources

ERIC Educational Resources Information Center

Zhao, Wanxia; Zou, Yonghua

2018-01-01

Purpose: This study aims to examine the cross-institutional variation in university greenness and analyze its underlying dynamics. Design/methodology/approach: This study constructs a University Greenness Index (UGI) and conducts multivariate regression. Findings: This study finds variation within two dimensions; in the vertical dimension,…

Microevolutionary dynamics of a macroevolutionary key innovation in a Lepidopteran herbivore

PubMed Central

2010-01-01

Background A molecular population genetics understanding is central to the study of ecological and evolutionary functional genomics. Population genetics identifies genetic variation and its distribution within and among populations, it reveals the demographic history of the populations studied, and can provide indirect insights into historical selection dynamics. Here we use this approach to examine the demographic and selective dynamics acting of a candidate gene involved in plant-insect interactions. Previous work documents the macroevolutionary and historical ecological importance of the nitrile-specifier protein (Nsp), which facilitated the host shift of Pieridae butterflies onto Brassicales host plants ~80 Myr ago. Results Here we assess the microevolutionary dynamics of the Nsp gene by studying the within and among-population variation at Nsp and reference genes in the butterfly Pieris rapae (Small Cabbage White). Nsp exhibits unexpectedly high amounts of amino acid polymorphism, unequally distributed across the gene. The vast majority of genetic variation exists within populations, with little to no genetic differentiation among four populations on two continents. A comparison of synonymous and nonsynonymous substitutions in 70 randomly chosen genes among P. rapae and its close relative Pieris brassicae (Large Cabbage White) finds Nsp to have a significantly relaxed functional constraint compared to housekeeping genes. We find strong evidence for a recent population expansion and no role for strong purifying or directional selection upon the Nsp gene. Conclusions The microevolutionary dynamics of the Nsp gene in P. rapae are dominated by recent population expansion and variation in functional constraint across the repeated domains of the Nsp gene. While the high amounts of amino acid diversity suggest there may be significant functional differences among allelic variants segregating within populations, indirect tests of selection could not conclusively identify a signature of historical selection. The importance of using this information for planning future studies of potential performance and fitness consequences of the observed variation is discussed. PMID:20181249

A clumpy stellar wind and luminosity-dependent cyclotron line revealed by the first Suzaku observation of the high-mass X-ray binary 4U 1538–522

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hemphill, Paul B.; Rothschild, Richard E.; Markowitz, Alex

2014-09-01

We present results from the first Suzaku observation of the high-mass X-ray binary 4U 1538–522. The broadband spectral coverage of Suzaku allows for a detailed spectral analysis, characterizing the cyclotron resonance scattering feature at 23.0 ± 0.4 keV and the iron Kα line at 6.426 ± 0.008 keV, as well as placing limits on the strengths of the iron Kβ line and the iron K edge. We track the evolution of the spectral parameters both in time and in luminosity, notably finding a significant positive correlation between cyclotron line energy and luminosity. A dip and spike in the light curvemore » is shown to be associated with an order-of-magnitude increase in column density along the line of sight, as well as significant variation in the underlying continuum, implying the accretion of a overdense region of a clumpy stellar wind. We also present a phase-resolved analysis, with most spectral parameters of interest showing significant variation with phase. Notably, both the cyclotron line energy and the iron Kα line intensity vary significantly with phase, with the iron line intensity significantly out of phase with the pulse profile. We discuss the implications of these findings in the context of recent work in the areas of accretion column physics and cyclotron resonance scattering feature formation.« less

Are the traditional large-scale drought indices suitable for shallow water wetlands? An example in the Everglades.

PubMed

Zhao, Dehua; Wang, Penghe; Zuo, Jie; Zhang, Hui; An, Shuqing; Ramesh, Reddy K

2017-08-01

Numerous drought indices have been developed over the past several decades. However, few studies have focused on the suitability of indices for studies of ephemeral wetlands. The objective is to answer the following question: can the traditional large-scale drought indices characterize drought severity in shallow water wetlands such as the Everglades? The question was approached from two perspectives: the available water quantity and the response of wetland ecosystems to drought. The results showed the unsuitability of traditional large-scale drought indices for characterizing the actual available water quantity based on two findings. (1) Large spatial variations in precipitation (P), potential evapotranspiration (PE), water table depth (WTD) and the monthly water storage change (SC) were observed in the Everglades; notably, the spatial variation in SC, which reflects the monthly water balance, was 1.86 and 1.62 times larger than the temporal variation between seasons and between years, respectively. (2) The large-scale water balance measured based on the water storage variation had an average indicating efficiency (IE) of only 60.01% due to the redistribution of interior water. The spatial distribution of variations in the Normalized Different Vegetation Index (NDVI) in the 2011 dry season showed significantly positive, significantly negative and weak correlations with the minimum WTD in wet prairies, graminoid prairies and sawgrass wetlands, respectively. The significant and opposite correlations imply the unsuitability of the traditional large-scale drought indices in evaluating the effect of drought on shallow water wetlands. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sex-related shape dimorphism in the human radiocarpal and midcarpal joints.

PubMed

Kivell, Tracy L; Guimont, Isabelle; Wall, Christine E

2013-01-01

Previous research has revealed significant size differences between human male and female carpal bones but it is unknown if there are significant shape differences as well. This study investigated sex-related shape variation and allometric patterns in five carpal bones that make up the radiocarpal and midcarpal joints in modern humans. We found that many aspects of carpal shape (76% of all variables quantified) were similar between males and females, despite variation in size. However, 10 of the shape ratios were significantly different between males and females, with at least one significant shape difference observed in each carpal bone. Within-sex standard major axis regressions (SMA) of the numerator (i.e., the linear variables) on the denominator (i.e., the geometric mean) for each significantly different shape ratio indicated that most linear variables scaled with positive allometry in both males and females, and that for eight of the shape ratios, sex-related shape variation is associated with statistically similar sex-specific scaling relationships. Only the length of the scaphoid body and the height of the lunate triquetrum facet showed a significantly higher SMA slope in females compared with males. These findings indicate that the significant differences in the majority of the shape ratios are a function of subtle (i.e., not statistically significant) scaling differences between males and females. There are a number of potential developmental, functional, and evolutionary factors that may cause sex-related shape differences in the human carpus. The results highlight the potential for subtle differences in scaling to result in functionally significant differences in shape. Copyright © 2012 Wiley Periodicals, Inc.

Atmospheric Fossil Fuel CO2 Traced by Δ(14)C in Beijing and Xiamen, China: Temporal Variations, Inland/Coastal Differences and Influencing Factors.

PubMed

Niu, Zhenchuan; Zhou, Weijian; Wu, Shugang; Cheng, Peng; Lu, Xuefeng; Xiong, Xiaohu; Du, Hua; Fu, Yunchong; Wang, Gehui

2016-06-07

One year of atmospheric Δ(14)CO2 were observed in 2014 in the inland city of Beijing and coastal city of Xiamen, China, to trace temporal CO2ff variations and to determine the factors influencing them. The average CO2ff concentrations at the sampling sites in Beijing and Xiamen were 39.7 ± 36.1 ppm and 13.6 ± 12.3 ppm, respectively. These contributed 75.2 ± 14.6% and 59.1 ± 26.8% to their respective annual ΔCO2 offsets over background CO2 concentrations. Significantly (p < 0.05) high CO2ff values were observed in winter in Beijing. We did not find any significant differences in CO2ff values between weekdays and weekends. Diurnal CO2ff variations were plainly evident, with high values between midnight and 4:00, and during morning and afternoon rush hours. The sampling site in the inland city of Beijing displayed much higher CO2ff inputs and overall temporal variations than the site in the coastal city of Xiamen. The variations of CO2ff at both sites were controlled by a combination of emission sources, topography, and atmospheric dispersion. In particular, diurnal observations at the urban site in Beijing showed that CO2ff was easily accumulated under the southeast wind conditions.

Seasonal variation in myocardial infarction is limited to patients with ST-elevations on admission.

PubMed

Leibowitz, David; Planer, David; Weiss, Teddy; Rott, David

2007-01-01

Previous studies have demonstrated seasonal variation in the incidence of acute myocardial infarction (AMI) with an increase in cases during the winter months. However, they did not assess whether ST-elevation MI (STEMI) and non-ST-elevation MI (NSTEMI) exhibit similar changes. The object of this study was to compare the seasonal variation of STEMI and NSTEMI. All patients who presented with AMI and underwent coronary angiography within seven days of admission were identified via the institutional database. STEMI diagnosis required admission ECG demonstrating ST elevation in at least two continguous leads. All AMIs not meeting criteria for STEMI were defined as NSTEMI. Patients were divided into monthly and seasonal groups based on the date of admission with MI. A total of 784 patients were included: 549 patients with STEMI and 235 with NSTEMI. When STEMI patients were analyzed by season, there were 170 patients (31%) in the winter months, a statistically significant difference of excess MI (p<0.005). When NSTEMI patients were analyzed, there were 62 patients (26%) in the winter with no statistically significant difference in the seasonal variation. Our findings suggest that the previously noted seasonal variation in the incidence of AMI is limited to patients presenting with STEMI, and that there are important physiological differences between STEMI and NSTEMI, the nature of which remains to be elucidated.

Altitudinal variation in age and body size in Yunnan pond frog (Pelophylax pleuraden).

PubMed

Lou, Shang Ling; Jin, Long; Liu, Yan Hong; Mi, Zhi Ping; Tao, Gang; Tang, Yu Mei; Liao, Wen Bo

2012-08-01

Large-scale systematic patterns of body size are a basic concern of evolutionary biology. Identifying body size variation along altitudinal gradients may help us to understand the evolution of life history of animals. In this study, we investigated altitudinal variation in body size, age and growth rate in Chinese endemic frog, Pelophylax pleuraden. Data sampled from five populations covering an altitudinal span of 1413 to 1935 m in Sichuan province revealed that body size from five populations did not co-vary with altitudes, not following Bergmann's rule. Average adult SVL differed significantly among populations in males, but not in females. For both sexes, average adult age differed significantly among populations. Post-metamorphic growth rate did not co-vary with altitude, and females grew faster than males in all populations. When controlling the effect of age, body size did not differ among populations in both sexes, suggesting that age did not affect variation in body size among populations. For females, there may be other factors, such as the allocation of energy between growth and reproduction, that eliminated the effect of age on body size. To our minds, the major reason of body size variation among populations in male frogs may be related to individual longevity. Our findings also suggest that factors other than age and growth rate may contribute to size differences among populations.

Developmental pathways from child maltreatment to adolescent marijuana dependence: Examining moderation by FK506 binding protein 5 gene (FKBP5).

PubMed

Handley, Elizabeth D; Rogosch, Fred A; Cicchetti, Dante

2015-11-01

The current study examined the prospective association between child maltreatment and the development of substance use disorder in adolescence with the aim of investigating pathways underlying this relation, as well as genetic moderation of these developmental mechanisms. Specifically, we tested whether youth who experienced maltreatment prior to age 8 were at risk for the development of marijuana dependence in adolescence by way of a childhood externalizing pathway and a childhood internalizing pathway. Moreover, we tested whether variation in FK506 binding protein 5 gene (FKBP5) CATT haplotype moderated these pathways. The participants were 326 children (n =179 maltreated; n = 147 nonmaltreated) assessed across two waves of data collection (childhood: ages 7-9 and adolescence: ages 15-18). Results indicated that higher levels of child externalizing symptoms significantly mediated the effect of child maltreatment on adolescent marijuana dependence symptoms for individuals with one or two copies of the FKBP5 CATT haplotype only. We did not find support for an internalizing pathway from child maltreatment to adolescent marijuana dependence, nor did we find evidence of moderation of the internalizing pathway by FKBP5 haplotype variation. Findings extend previous research by demonstrating that whether a maltreated child will traverse an externalizing pathway toward substance use disorder in adolescence is dependent on FKBP5 genetic variation.

Solar Cycle Dependence of the Diurnal Anisotropy of 0.6 TeV Cosmic-ray Intensity Observed with the Matsushiro Underground Muon Detector

NASA Astrophysics Data System (ADS)

Munakata, K.; Mizoguchi, Y.; Kato, C.; Yasue, S.; Mori, S.; Takita, M.; Kóta, J.

2010-04-01

We analyze the temporal variation of the diurnal anisotropy of sub-TeV cosmic-ray intensity observed with the Matsushiro (Japan) underground muon detector over two full solar activity cycles in 1985-2008. We find an anisotropy component in the solar diurnal anisotropy superimposed on the Compton-Getting anisotropy due to Earth's orbital motion around the Sun. The phase of this additional anisotropy is almost constant at ~15:00 local solar time corresponding to the direction perpendicular to the average interplanetary magnetic field at Earth's orbit, while the amplitude varies between a maximum (0.043% ± 0.002%) and minimum (~0.008% ± 0.002%) in a clear correlation with the solar activity. We find a significant time lag between the temporal variations of the amplitude and the sunspot number (SSN) and obtain the best correlation coefficient of +0.74 with the SSN delayed for 26 months. We suggest that this anisotropy might be interpreted in terms of the energy change due to the solar-wind-induced electric field expected for galactic cosmic rays (GCRs) crossing the wavy neutral sheet. The average amplitude of the sidereal diurnal variation over the entire period is 0.034% ± 0.003%, which is roughly one-third of the amplitude reported from air shower and deep-underground muon experiments monitoring multi-TeV GCR intensity suggesting a significant attenuation of the anisotropy due to the solar modulation. We find, on the other hand, only a weak positive correlation between the sidereal diurnal anisotropy and the solar activity cycle in which the amplitude in the "active" solar activity epoch is about twice the amplitude in the "quiet" solar activity epoch. This implies that only one-fourth of the total attenuation varies in correlation with the solar activity cycle and/or the solar magnetic cycle. We finally examine the temporal variation of the "single-band valley depth" (SBVD) quoted by the Milagro experiment and, in contrast with recent Milagro's report, we find no steady increase in the Matsushiro observations in a seven-year period between 2000 and 2007. We suggest, therefore, that the steady increase of the SBVD reported by the Milagro experiment is not caused by the decreasing solar modulation in the declining phase of the 23rd solar activity cycle.

Individual Differences in Dynamic Functional Brain Connectivity across the Human Lifespan.

PubMed

Davison, Elizabeth N; Turner, Benjamin O; Schlesinger, Kimberly J; Miller, Michael B; Grafton, Scott T; Bassett, Danielle S; Carlson, Jean M

2016-11-01

Individual differences in brain functional networks may be related to complex personal identifiers, including health, age, and ability. Dynamic network theory has been used to identify properties of dynamic brain function from fMRI data, but the majority of analyses and findings remain at the level of the group. Here, we apply hypergraph analysis, a method from dynamic network theory, to quantify individual differences in brain functional dynamics. Using a summary metric derived from the hypergraph formalism-hypergraph cardinality-we investigate individual variations in two separate, complementary data sets. The first data set ("multi-task") consists of 77 individuals engaging in four consecutive cognitive tasks. We observe that hypergraph cardinality exhibits variation across individuals while remaining consistent within individuals between tasks; moreover, the analysis of one of the memory tasks revealed a marginally significant correspondence between hypergraph cardinality and age. This finding motivated a similar analysis of the second data set ("age-memory"), in which 95 individuals, aged 18-75, performed a memory task with a similar structure to the multi-task memory task. With the increased age range in the age-memory data set, the correlation between hypergraph cardinality and age correspondence becomes significant. We discuss these results in the context of the well-known finding linking age with network structure, and suggest that hypergraph analysis should serve as a useful tool in furthering our understanding of the dynamic network structure of the brain.

Evidence for Interannual to Decadal Variations in Hadley and Walker Circulations and Links to Water and Energy Fluxes

NASA Technical Reports Server (NTRS)

Robertson, Franklin; Bosilovich, Michael; Miller, Timothy

2007-01-01

Mass and energy transports associated with the Hadley and Walker circulations are important components of the earth s climate system and are strongly linked to hydrologic processes. Interannual to decadal variation in these flows likely signify a combination of natural climate noise as well as a response to anthropgenic forcing. There remains considerable uncertainty in quantifying variations in these flows. Evidence in the surface pressure record supports a weakening of the Walker circulation over the Pacific in recent decades. Conversely the NCEP / NCAR and ERA 40 reanalyses indicate that the Hadley circulation has increased in strength over the last two decades, though these analyses depict significantly different mass circulation changes. Interestingly, the NCEP - II / DOE reanalysis contains essentially no Hadley circulation changes. Most climate model integrations anticipate a weakening of both tropical circulations associated with stronger static stability. Clearly there is much uncertainty not only with the mass transports, but also how they are linked to water and energy balance of the planet through variations in turbulent heat and radiative fluxes and horizontal exports / imports of energy. Here we examine heat and water budget variations from a number of reanalysis products and focus on the linear and nonlinear response of ENSO warm and cold events as opportunities to study budget variations over the past 15-20 years. Our analysis addresses such questions as To what extent do Hadley and Walker Cell variations compensate each other on mass and energy transport? Do static stability adjustments appear to constrain fractional precipitation response vs. fractional water vapor response? We appeal to constraints offered by GPCP precipitation, SSWI ocean evaporation estimates, and ISCCP-FD radiative fluxes, and other satellite data sets to interpret and confirm reanalysis-based diagnostics. Using our findings we also attempt to place in context the recent findings that tropical ocean evaporation increased by order 5% or more during the 1990s, reconciling this with GPCP precipitation variations.

Fecundity and life table of different morphotypes of Phlebotomus argentipes (Diptera: Psychodidae).

PubMed

Dinesh, D S; Kumar, A J; Kumar, V; Ranjan, A; Das, P

2011-10-01

Phlebotomus argentipes Annandale and Brunetti (Diptera: Psychodidae), the established vector for Visceral Leishmaniasis (VL) have shown some morphological variations in India and its subcontinents. The variable egg laying capacity was found in different morphotypes of P. argentipes with maximum in type III followed by type I and II. The fecundity was enhanced by providing 25% glucose soaked filter paper surface in all types. However, significant increase was found in type-I (P < 0.05). The differences in fecundity indicate the biological variations among P. argentipes population. The findings will be helpful in searching out the sibling species among P. argentipes population.

Sex ratio variation shapes the ecological effects of a globally introduced freshwater fish

PubMed Central

Fryxell, David C.; Arnett, Heather A.; Apgar, Travis M.; Kinnison, Michael T.; Palkovacs, Eric P.

2015-01-01

Sex ratio and sexual dimorphism have long been of interest in population and evolutionary ecology, but consequences for communities and ecosystems remain untested. Sex ratio could influence ecological conditions whenever sexual dimorphism is associated with ecological dimorphism in species with strong ecological interactions. We tested for ecological implications of sex ratio variation in the sexually dimorphic western mosquitofish, Gambusia affinis. This species causes strong pelagic trophic cascades and exhibits substantial variation in adult sex ratios. We found that female-biased populations induced stronger pelagic trophic cascades compared with male-biased populations, causing larger changes to key community and ecosystem responses, including zooplankton abundance, phytoplankton abundance, productivity, pH and temperature. The magnitude of such effects indicates that sex ratio is important for mediating the ecological role of mosquitofish. Because both sex ratio variation and sexual dimorphism are common features of natural populations, our findings should encourage broader consideration of the ecological significance of sex ratio variation in nature, including the relative contributions of various sexually dimorphic traits to these effects. PMID:26490793

Natural variation in learning rate and memory dynamics in parasitoid wasps: opportunities for converging ecology and neuroscience

PubMed Central

Hoedjes, Katja M.; Kruidhof, H. Marjolein; Huigens, Martinus E.; Dicke, Marcel; Vet, Louise E. M.; Smid, Hans M.

2011-01-01

Although the neural and genetic pathways underlying learning and memory formation seem strikingly similar among species of distant animal phyla, several more subtle inter- and intraspecific differences become evident from studies on model organisms. The true significance of such variation can only be understood when integrating this with information on the ecological relevance. Here, we argue that parasitoid wasps provide an excellent opportunity for multi-disciplinary studies that integrate ultimate and proximate approaches. These insects display interspecific variation in learning rate and memory dynamics that reflects natural variation in a daunting foraging task that largely determines their fitness: finding the inconspicuous hosts to which they will assign their offspring to develop. We review bioassays used for oviposition learning, the ecological factors that are considered to underlie the observed differences in learning rate and memory dynamics, and the opportunities for convergence of ecology and neuroscience that are offered by using parasitoid wasps as model species. We advocate that variation in learning and memory traits has evolved to suit an insect's lifestyle within its ecological niche. PMID:21106587

Examining Variation in the Impact of School-Wide Positive Behavioral Interventions and Supports: Findings from a Randomized Controlled Effectiveness Trial

ERIC Educational Resources Information Center

Bradshaw, Catherine P.; Waasdorp, Tracy E.; Leaf, Philip J.

2015-01-01

School-Wide Positive Behavioral Interventions and Supports (SWPBIS; Sugai & Horner, 2006) is currently implemented in over 20,000 schools across the country with the goal of preventing disruptive behavior problems and enhancing the school climate. While previous studies have indicated significant main effects of SWPBIS on student outcomes, the…

Different Values, Different Skills? A Comparison of Essay Writing by Students from Arts and Science Backgrounds

ERIC Educational Resources Information Center

North, Sarah

2005-01-01

This article reports the findings of a 3 year research project which investigated disciplinary variation in student writing. Within an Open University course in the history of science, students from an arts background were found to achieve significantly higher grades than those from a science background. Textual and interview data suggest that…

Association Analyses of RANKL/RANK/OPG Gene Polymorphisms with Femoral Neck Compression Strength Index Variation in Caucasians

PubMed Central

Dong, Shan-Shan; Liu, Xiao-Gang; Chen, Yuan; Guo, Yan; Wang, Liang; Zhao, Jian; Xiong, Dong-Hai; Xu, Xiang-Hong; Recker, Robert R.

2010-01-01

Femoral neck compression strength index (fCSI), a novel phenotypic parameter that integrates bone density, bone size, and body size, has significant potential to improve hip fracture risk assessment. The genetic factors underlying variations in fCSI, however, remain largely unknown. Given the important roles of the receptor activator of the nuclear factor-κB ligand/receptor activator of the nuclear factor-κB/osteoprotegerin (RANKL/RANK/OPG) pathway in the regulation of bone remodeling, we tested the associations between RANKL/RANK/OPG polymorphisms and variations in fCSI as well as its components (femoral neck bone mineral density [fBMD], femoral neck width [FNW], and weight). This was accomplished with a sample comprising 1873 subjects from 405 Caucasian nuclear families. Of the 37 total SNPs studied in these three genes, 3 SNPs, namely, rs12585014, rs7988338, and rs2148073, of RANKL were significantly associated with fCSI (P = 0.0007, 0.0007, and 0.0005, respectively) after conservative Bonferroni correction. Moreover, the three SNPs were approximately in complete linkage disequilibrium. Haplotype-based association tests corroborated the single-SNP results since haplotype 1 of block 1 of the RANKL gene achieved an even more significant association with fCSI (P = 0.0003) than any of the individual SNPs. However, we did not detect any significant associations of these genes with fBMD, FNW, or weight. In summary, our findings suggest that the RANKL gene may play an important role in variation in fCSI, independent of fBMD and non-fBMD components. PMID:19458885

Association analyses of RANKL/RANK/OPG gene polymorphisms with femoral neck compression strength index variation in Caucasians.

PubMed

Dong, Shan-Shan; Liu, Xiao-Gang; Chen, Yuan; Guo, Yan; Wang, Liang; Zhao, Jian; Xiong, Dong-Hai; Xu, Xiang-Hong; Recker, Robert R; Deng, Hong-Wen

2009-08-01

Femoral neck compression strength index (fCSI), a novel phenotypic parameter that integrates bone density, bone size, and body size, has significant potential to improve hip fracture risk assessment. The genetic factors underlying variations in fCSI, however, remain largely unknown. Given the important roles of the receptor activator of the nuclear factor-kappaB ligand/receptor activator of the nuclear factor-kappaB/osteoprotegerin (RANKL/RANK/OPG) pathway in the regulation of bone remodeling, we tested the associations between RANKL/RANK/OPG polymorphisms and variations in fCSI as well as its components (femoral neck bone mineral density [fBMD], femoral neck width [FNW], and weight). This was accomplished with a sample comprising 1873 subjects from 405 Caucasian nuclear families. Of the 37 total SNPs studied in these three genes, 3 SNPs, namely, rs12585014, rs7988338, and rs2148073, of RANKL were significantly associated with fCSI (P = 0.0007, 0.0007, and 0.0005, respectively) after conservative Bonferroni correction. Moreover, the three SNPs were approximately in complete linkage disequilibrium. Haplotype-based association tests corroborated the single-SNP results since haplotype 1 of block 1 of the RANKL gene achieved an even more significant association with fCSI (P = 0.0003) than any of the individual SNPs. However, we did not detect any significant associations of these genes with fBMD, FNW, or weight. In summary, our findings suggest that the RANKL gene may play an important role in variation in fCSI, independent of fBMD and non-fBMD components.

Influence of Microphysical Variability on Stochastic Condensation in Turbulent Clouds

NASA Astrophysics Data System (ADS)

Desai, N.; Chandrakar, K. K.; Chang, K.; Glienke, S.; Cantrell, W. H.; Fugal, J. P.; Shaw, R. A.

2017-12-01

We investigate the influence of variability in droplet number concentration and radius on the evolution of cloud droplet size distributions. Measurements are made on the centimeter scale using digitial inline holography, both in a controlled laboratory setting and in the field using HOLODEC measurements from CSET. We created steady state cloud conditions in the laboratory Pi Chamber, in which a turbulent cloud can be sustained for long periods of time. Using holographic imaging, we directly observe the variations in local number concentration and droplet size distribution and, thereby, the integral radius. We interpret the measurements in the context of stochastic condensation theory to determine how fluctuations in integral radius contribute to droplet growth. We find that the variability in integral radius is primarily driven by variations in the droplet number concentration and not the droplet radius. This variability does not contribute significantly to the mean droplet growth rate, but contributes significantly to the rate of increase of the size distribution width. We compare these results with in-situ measurements and find evidence for microphysical signatures of stochastic condensation. The results suggest that supersaturation fluctuations lead to broader size distributions and allow droplets to reach the collision-coalescence stage.

Are effort-reward imbalance and social isolation mediating the association between education and depressiveness? Baseline findings from the lidA(§)-study.

PubMed

du Prel, Jean-Baptist; Iskenius, Mario; Peter, Richard

2014-12-01

To investigate multiple mediations of the association between education and depressive symptoms (BDI-V) by work-related stress (ERI) and social isolation, the regional variation of the first mediation and a potential moderating effect of regional unemployment rate. 6339 employees born in 1959 and 1965 were randomly recruited from 222 sample points in a German cohort study on work, age, health and work participation. A multilevel model of moderated lower-level mediation was used to investigate the confirmatory research question. Multiple mediations were tested corresponding to Baron and Kenny. These analyses were stratified for age and adjusted for sex, negative affectivity and overcommitment. In the association between education and depressive symptoms, indirect effects of work-related stress and social isolation were significant in both age cohorts whereas a direct association was observable in the younger cohort, only. The significant regional variation in the association between work-related stress and depressive symptoms was not statistically explained by regional unemployment rate. Our findings point out that work-related stress and social isolation play an intermediary role between education and depressive symptoms in middle-aged employees.

Post-Injection Induced Seismicity in EGS: Triggering Mechanisms and Mitigation.

NASA Astrophysics Data System (ADS)

De Simone, S.; Carrera, J.; Vilarrasa, V.

2017-12-01

Induced microseismicity is a controversial issue related to Enhanced Geothermal Systems (EGS) and in general with fluid injection into deep geological formations. The occurring of felt earthquakes after stopping injection especially generates concern, because the correlation between injection and seismic activity is unclear. The aim of this work is to advance in the understanding of the processes that may induce or trigger co- and post-injection seismicity. To this end we investigate the thermo-hydro-mechanical coupling by means of numerical simulations of hydraulic stimulation of deep geothermal systems. We find that preferential flow through conductive fractures or fault zones provokes pressure and temperature perturbations that result in not only heterogeneous variation of the stress field, but also highly anisotropic variations of the local stress tensor. Anisotropic variations tend to stabilize some fractures, but destabilize others. Moreover, activation of shear slip causes a significant variation of the stress field that enlarges the range of critical fracture orientations. We find that post-injection seismicity may occur on non-critically oriented faults that were originally stable. During injection, such faults become destabilized by thermal and shear slip stress changes, but remain static by the superposition of the stabilizing effect of pressure forces. However, these fractures become unstable and fail when the pressure forcing dissipates shortly after injection stops abruptly, which suggests that a slow reduction in injection rate may mitigate post-injection seismicity.

Identifying with fictive characters: structural brain correlates of the personality trait 'fantasy'.

PubMed

Cheetham, Marcus; Hänggi, Jürgen; Jancke, Lutz

2014-11-01

The perception of oneself as absorbed in the thoughts, feelings and happenings of a fictive character (e.g. in a novel or film) as if the character's experiences were one's own is referred to as identification. We investigated whether individual variation in the personality trait of identification is associated with individual variation in the structure of specific brain regions, using surface and volume-based morphometry. The hypothesized regions of interest were selected on the basis of their functional role in subserving the cognitive processing domains considered important for identification (i.e. mental imagery, empathy, theory of mind and merging) and for the immersive experience called 'presence'. Controlling for age, sex, whole-brain volume and other traits, identification covaried significantly with the left hippocampal volume, cortical thickness in the right anterior insula and the left dorsal medial prefrontal cortex, and with gray matter volume in the dorsolateral prefrontal cortex. These findings show that trait identification is associated with structural variation in specific brain regions. The findings are discussed in relation to the potential functional contribution of these regions to identification. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Poison frog colors are honest signals of toxicity, particularly for bird predators.

PubMed

Maan, Martine E; Cummings, Molly E

2012-01-01

Antipredator defenses and warning signals typically evolve in concert. However, the extensive variation across taxa in both these components of predator deterrence and the relationship between them are poorly understood. Here we test whether there is a predictive relationship between visual conspicuousness and toxicity levels across 10 populations of the color-polymorphic strawberry poison frog, Dendrobates pumilio. Using a mouse-based toxicity assay, we find extreme variation in toxicity between frog populations. This variation is significantly positively correlated with frog coloration brightness, a viewer-independent measure of visual conspicuousness (i.e., total reflectance flux). We also examine conspicuousness from the view of three potential predator taxa, as well as conspecific frogs, using taxon-specific visual detection models and three natural background substrates. We find very strong positive relationships between frog toxicity and conspicuousness for bird-specific perceptual models. Weaker but still positive correlations are found for crab and D. pumilio conspecific visual perception, while frog coloration as viewed by snakes is not related to toxicity. These results suggest that poison frog colors can be honest signals of prey unpalatability to predators and that birds in particular may exert selection on aposematic signal design. © 2011 by The University of Chicago.

Ethnic Variations in Prevalence of High-Risk Sexual Behaviors Among Asian and Pacific Islander Adolescents in Hawaii

PubMed Central

Kameoka, Velma A.

2009-01-01

Objectives. We examined ethnic variations in high-risk sexual behaviors among Asian and Pacific Islander (API) adolescents in comparison with White adolescents. Methods. We obtained data from the 2003 Hawaii Youth Risk Behavior Survey on 4953 students in grades 9 through 12. We conducted χ2 and logistic regression analyses on these data to examine the prevalence of high-risk sexual behaviors among Japanese, Filipino, Native Hawaiian, and White adolescents. Results. We found significant ethnic variation in prevalence of high-risk sexual behaviors among API adolescents. Relative to White adolescents, Native Hawaiian adolescents were most likely to engage in lifetime sexual intercourse, recent sexual intercourse, and sexual initiation before age 13 years; Japanese adolescents were least likely to engage in these behaviors. Filipino adolescents were least likely to use substances before last sexual intercourse and condoms during last sexual intercourse. Conclusions. Our findings suggest divergent patterns of risk among API ethnic groups, underscoring the heterogeneity of API subgroups and emphasizing the need for health disparities research on disaggregated API ethnic groups. The findings of such research should be used to design ethnically relevant interventions aimed at mitigating the negative health consequences of high-risk sexual behaviors. PMID:19106424

Does oxidative stress shorten telomeres?

PubMed

Boonekamp, Jelle J; Bauch, Christina; Mulder, Ellis; Verhulst, Simon

2017-05-01

Oxidative stress shortens telomeres in cell culture, but whether oxidative stress explains variation in telomere shortening in vivo at physiological oxidative stress levels is not well known. We therefore tested for correlations between six oxidative stress markers and telomere attrition in nestling birds (jackdaws Corvus monedula ) that show a high rate of telomere attrition in early life. Telomere attrition was measured between ages 5 and 30 days, and was highly variable (average telomere loss: 323 bp, CV = 45%). Oxidative stress markers were measured in blood at age 20 days and included markers of oxidative damage (TBARS, dROMs and GSSG) and markers of antioxidant protection (GSH, redox state, uric acid). Variation in telomere attrition was not significantly related to these oxidative stress markers (| r | ≤ 0.08, n = 87). This finding raises the question whether oxidative stress accelerates telomere attrition in vivo The accumulation of telomere attrition over time depends both on the number of cell divisions and on the number of base pairs lost per DNA replication and, based on our findings, we suggest that in a growing animal cell proliferation, dynamics may be more important for explaining variation in telomere attrition than oxidative stress. © 2017 The Author(s).

Genome-Wide Analysis of Polymorphisms Associated with Cytokine Responses in Smallpox Vaccine Recipients

PubMed Central

Kennedy, Richard B.; Ovsyannikova, Inna G.; Pankratz, V. Shane; Haralambieva, Iana H.; Vierkant, Robert A.; Poland, Gregory A.

2014-01-01

The role that genetics plays in response to infection or disease is becoming increasingly clear as we learn more about immunogenetics and host-pathogen interactions. Here we report a genome-wide analysis of the effects of host genetic variation on cytokine responses to vaccinia virus stimulation in smallpox vaccine recipients. Our data show that vaccinia stimulation of immune individuals results in secretion of inflammatory and Th1 cytokines. We identified multiple SNPs significantly associated with variations in cytokine secretion. These SNPs are found in genes with known immune function, as well as in genes encoding for proteins involved in signal transduction, cytoskeleton, membrane channels and ion transport, as well as others with no previously identified connection to immune responses. The large number of significant SNP associations implies that cytokine secretion in response to vaccinia virus is a complex process controlled by multiple genes and gene families. Follow-up studies to replicate these findings and then pursue mechanistic studies will provide a greater understanding of how genetic variation influences vaccine responses. PMID:22610502

Population and allelic variation of A-to-I RNA editing in human transcriptomes.

PubMed

Park, Eddie; Guo, Jiguang; Shen, Shihao; Demirdjian, Levon; Wu, Ying Nian; Lin, Lan; Xing, Yi

2017-07-28

A-to-I RNA editing is an important step in RNA processing in which specific adenosines in some RNA molecules are post-transcriptionally modified to inosines. RNA editing has emerged as a widespread mechanism for generating transcriptome diversity. However, there remain significant knowledge gaps about the variation and function of RNA editing. In order to determine the influence of genetic variation on A-to-I RNA editing, we integrate genomic and transcriptomic data from 445 human lymphoblastoid cell lines by combining an RNA editing QTL (edQTL) analysis with an allele-specific RNA editing (ASED) analysis. We identify 1054 RNA editing events associated with cis genetic polymorphisms. Additionally, we find that a subset of these polymorphisms is linked to genome-wide association study signals of complex traits or diseases. Finally, compared to random cis polymorphisms, polymorphisms associated with RNA editing variation are located closer spatially to their respective editing sites and have a more pronounced impact on RNA secondary structure. Our study reveals widespread cis variation in RNA editing among genetically distinct individuals and sheds light on possible phenotypic consequences of such variation on complex traits and diseases.

On the source of stochastic volatility: Evidence from CAC40 index options during the subprime crisis

NASA Astrophysics Data System (ADS)

Slim, Skander

2016-12-01

This paper investigates the performance of time-changed Lévy processes with distinct sources of return volatility variation for modeling cross-sectional option prices on the CAC40 index during the subprime crisis. Specifically, we propose a multi-factor stochastic volatility model: one factor captures the diffusion component dynamics and two factors capture positive and negative jump variations. In-sample and out-of-sample tests show that our full-fledged model significantly outperforms nested lower-dimensional specifications. We find that all three sources of return volatility variation, with different persistence, are needed to properly account for market pricing dynamics across moneyness, maturity and volatility level. Besides, the model estimation reveals negative risk premium for both diffusive volatility and downward jump intensity whereas a positive risk premium is found to be attributed to upward jump intensity.

On the X-Ray Variability of Magnetar 1RXS J170849.0-400910

NASA Technical Reports Server (NTRS)

Scholz, P.; Archibald, R. F.; Kaspi, V. M.; Ng, C.-Y.; Beardmore, A. P.; Gehrels, C.; Kennea, J. A.

2014-01-01

We present a long-term X-ray flux and spectral analysis for 1RXS J170849.0-400910 using Swift/XRT spanning over 8 years from 2005-2013. We also analyze two observations from Chandra and XMM in the period from 2003-2004. In this 10-yr period, 1RXS J170849.0-400910 displayed several rotational glitches. Previous studies have claimed variations in the X-ray emission associated with some of the glitches. From our analysis we find no evidence for significant X-ray flux variations and evidence for only low-level spectral variations. We also present an updated timing solution for 1RXS J170849.0-400910, from RXTE and Swift observations, which includes a previously unreported glitch at MJD 56019. We discuss the frequency and implications of radiatively quiet glitches in magnetars.

Sociodemographic and socioeconomic variations in leisure time physical activity in a sample of Hungarian youth.

PubMed

Piko, Bettina F; Keresztes, Noémi

2008-01-01

The main goal of the present study is to detect the relationship between youth's leisure time physical activity and a set of sociodemographic (age, gender, family stucture) and socioeconomic variables (SES and parental schooling). Data were collected among Hungarian youth (middle and high school students, N = 1662) aged between 10-20 years using a self-administered questionnaire. Our findings did not indicate gender differences during the years of middle school, whereas gender differences became significant during the years of high school. In multivariate analyses, parental schooling played a decisive role in youth's physical activity, wheres SES self-assessment did not remain significant. These findings provide some useful information on characteristics of the target groups for health education programs.

Integrative analysis of RNA, translation, and protein levels reveals distinct regulatory variation across humans.

PubMed

Cenik, Can; Cenik, Elif Sarinay; Byeon, Gun W; Grubert, Fabian; Candille, Sophie I; Spacek, Damek; Alsallakh, Bilal; Tilgner, Hagen; Araya, Carlos L; Tang, Hua; Ricci, Emiliano; Snyder, Michael P

2015-11-01

Elucidating the consequences of genetic differences between humans is essential for understanding phenotypic diversity and personalized medicine. Although variation in RNA levels, transcription factor binding, and chromatin have been explored, little is known about global variation in translation and its genetic determinants. We used ribosome profiling, RNA sequencing, and mass spectrometry to perform an integrated analysis in lymphoblastoid cell lines from a diverse group of individuals. We find significant differences in RNA, translation, and protein levels suggesting diverse mechanisms of personalized gene expression control. Combined analysis of RNA expression and ribosome occupancy improves the identification of individual protein level differences. Finally, we identify genetic differences that specifically modulate ribosome occupancy--many of these differences lie close to start codons and upstream ORFs. Our results reveal a new level of gene expression variation among humans and indicate that genetic variants can cause changes in protein levels through effects on translation. © 2015 Cenik et al.; Published by Cold Spring Harbor Laboratory Press.

Spatial variation of the Universal Thermal Climate Index in Lublin in specified weather scenarios / Zróżnicowanie przestrzenne wskaźnika UTCI w Lublinie w określonych scenariuszach pogodowych

NASA Astrophysics Data System (ADS)

Dobek, Mateusz; Demczuk, Piotr; Nowosad, Marek

2013-06-01

Due to the diversified land relief and presence of numerous gorge dissections intensively used by man largely for recreational purposes, Lublin is a valuable study area in terms of bioclimatology. The results of modelling of the variation of the bioclimatic conditions of Lublin provide information useful e.g. in the economy and spatial planning. The determined features of the city's bioclimate can be a significant element in the selection of locations for new residential and recreational investments. Knowledge on the spatial variation of biometeorological situations positively and negatively influencing the human organism can also find application in activities concerning the improvement of life quality and health protection, as well as in tourism and recreation. The objective of the paper is to present the spatial variation of biometeorological conditions in Lublin based on the example of specified weather scenarios.

Nebular and Stellar Dust Extinction Across the Disk of Emission-line Galaxies on Kiloparsec Scales

NASA Astrophysics Data System (ADS)

Hemmati, Shoubaneh; Mobasher, Bahram; Darvish, Behnam; Nayyeri, Hooshang; Sobral, David; Miller, Sarah

2015-11-01

We investigate the resolved kiloparsec-scale stellar and nebular dust distribution in eight star-forming galaxies at z ∼ 0.4 in the Great Observatories Origins Deep Survey fields. This is to get a better understanding of the effect of dust attenuation on measurements of physical properties and its variation with redshift. Constructing the observed spectral energy distributions (SEDs) per pixel, based on seven bands of photometric data from Hubble Space Telescope/Advanced Camera for Surveys and WFC3, we performed pixel-by-pixel SED fits to population synthesis models and estimated the small-scale distribution of stellar dust extinction. We use Hα/Hβ nebular emission line ratios from Keck/DEIMOS high-resolution spectra at each spatial resolution element to measure the amount of attenuation faced by ionized gas at different radii from the centers of galaxies. We find a good agreement between the integrated and median of resolved color excess measurements in our galaxies. The ratio of integrated nebular to stellar dust extinction is always greater than unity, but does not show any trend with stellar mass or star formation rate (SFR). We find that inclination plays an important role in the variation of the nebular to stellar excess ratio. The stellar color excess profiles are found to have higher values at the center compared to outer parts of the disk. However, for lower mass galaxies, a similar trend is not found for the nebular color excess. We find that the nebular color excess increases with stellar mass surface density. This explains the absence of radial trend in the nebular color excess in lower mass galaxies which lack a large radial variation of stellar mass surface density. Using standard conversions of SFR surface density to gas mass surface density, and the relation between dust mass surface density and color excess, we find no significant variation in the dust-to-gas ratio in regions with high gas mass surface densities over the scales probed in this study.

Influence of allelic variations in relation to norepinephrine and mineralocorticoid receptors on psychopathic traits: a pilot study

PubMed Central

2018-01-01

Background Past findings support a relationship between abnormalities in the amygdala and the presence of psychopathic traits. Among other genes and biomarkers relevant to the amygdala, norepinephrine and mineralocorticoid receptors might both play a role in psychopathy due to their association with traits peripheral to psychopathy. The purpose is to examine if allelic variations in single nucleotide polymorphisms related to norepinephrine and mineralocorticoid receptors play a role in the display of psychopathic traits and executive functions. Methods Fifty-seven healthy participants from the community provided a saliva sample for SNP sampling of rs5522 and rs5569. Participants then completed the Psychopathic Personality Inventory–Short Form (PPI-SF) and the Tower of Hanoi. Results Allelic variations of both rs5522 and rs5569 were significant when compared to PPI-SF total score and the fearless dominance component of the PPI-SF. A significant result was also obtained between rs5522 and the number of moves needed to complete the 5-disk Tower of Hanoi. Conclusion This pilot study offers preliminary results regarding the effect of allelic variations in SNPs related to norepinephrine and mineralocorticoid receptors on the presence of psychopathic traits. Suggestions are provided to enhance the reliability and validity of a larger-scale study. PMID:29576985

Seasonality of suicide behavior in Northwest Alaska: 1990-2009.

PubMed

Silveira, M L; Wexler, L; Chamberlain, J; Money, K; Spencer, R M C; Reich, N G; Bertone-Johnson, E R

2016-08-01

Suicide is a leading cause of death worldwide, and disproportionately affects Indigenous populations. Seasonal suicide patterns are variable in the literature, and could offer novel approaches to the timing and focus of prevention efforts if better understood. With a suicide surveillance system in place since 1989, this study offers an unprecedented opportunity to explore seasonal variations in both fatal and non-fatal suicide behavior in an Indigenous Arctic region. Cross-sectional. In this descriptive study, we analyzed data collected from 1990 to 2009 in the rural northwest region of Alaska, both graphically and using the chi-squared test for multinomials. We found a significant monthly variation for suicide attempts, with a peak in suicide behavior observed between April and August (P = 0.0002). Monthly variation was more pronounced among individuals ≤29 years of age, and was present in both males and females, although the seasonal pattern differed by sex. Our findings of a significant seasonal pattern in suicide behavior, with monthly variation (summer peak) in non-fatal suicide behavior among younger age groups, and among both males and females can assist planners in targeting subpopulations for prevention at different times of the year. Copyright © 2016 The Royal Society for Public Health. All rights reserved.

OXTR polymorphism predicts social relationships through its effects on social temperament

PubMed Central

Wright, Aidan G. C.; Troxel, Wendy M.; Ferrell, Robert E.; Flory, Janine D.; Manuck, Stephen B.

2015-01-01

Humans have a fundamental need for strong interpersonal bonds, yet individuals differ appreciably in their degree of social integration. That these differences are also substantially heritable has spurred interest in biological mechanisms underlying the quality and quantity of individuals’ social relationships. We propose that polymorphic variation in the oxytocin receptor gene (OXTR) associates with complex social behaviors and social network composition through intermediate effects on negative affectivity and the psychological processing of socially relevant information. We tested a hypothesized social cascade from the molecular level (OXTR variation) to the social environment, through negative affectivity and inhibited sociality, in a sample of 1295 men and women of European American (N = 1081) and African American (N = 214) ancestry. Compared to European Americans having any T allele of rs1042778, individuals homozygous for the alternate G allele reported significantly lower levels of negative affectivity and inhibited sociality, which in turn predicted significantly higher levels of social support and a larger/more diverse social network. Moreover, the effect of rs1042778 variation on social support was fully accounted for by associated differences in negative affectivity and inhibited sociality. Results replicated in the African American sample. Findings suggest that OXTR variation modulates levels of social support via proximal impacts on individual temperament. PMID:25326040

Variations between Dust and Gas in the Diffuse Interstellar Medium. III. Changes in Dust Properties

NASA Astrophysics Data System (ADS)

Reach, William T.; Bernard, Jean-Philippe; Jarrett, Thomas H.; Heiles, Carl

2017-12-01

We study infrared emission of 17 isolated, diffuse clouds with masses of order {10}2 {M}ȯ to test the hypothesis that grain property variations cause the apparently low gas-to-dust ratios that have been measured in those clouds. Maps of the clouds were constructed from Wide-field Infrared Survey Explorer (WISE) data and directly compared with the maps of dust optical depth from Planck. The mid-infrared emission per unit dust optical depth has a significant trend toward lower values at higher optical depths. The trend can be quantitatively explained by the extinction of starlight within the clouds. The relative amounts of polycyclic aromatic hydrocarbon and very small grains traced by WISE, compared with large grains tracked by Planck, are consistent with being constant. The temperature of the large grains significantly decreases for clouds with larger dust optical depth; this trend is partially due to dust property variations, but is primarily due to extinction of starlight. We updated the prediction for molecular hydrogen column density, taking into account variations in dust properties, and find it can explain the observed dust optical depth per unit gas column density. Thus, the low gas-to-dust ratios in the clouds are most likely due to “dark gas” that is molecular hydrogen.

ASSESSING THE INFLUENCE OF THE SOLAR ORBIT ON TERRESTRIAL BIODIVERSITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, F.; Bailer-Jones, C. A. L.

The terrestrial record shows a significant variation in the extinction and origination rates of species during the past half-billion years. Numerous studies have claimed an association between this variation and the motion of the Sun around the Galaxy, invoking the modulation of cosmic rays, gamma rays, and comet impact frequency as a cause of this biodiversity variation. However, some of these studies exhibit methodological problems, or were based on coarse assumptions (such as a strict periodicity of the solar orbit). Here we investigate this link in more detail, using a model of the Galaxy to reconstruct the solar orbit andmore » thus a predictive model of the temporal variation of the extinction rate due to astronomical mechanisms. We compare these predictions as well as those of various reference models with paleontological data. Our approach involves Bayesian model comparison, which takes into account the uncertainties in the paleontological data as well as the distribution of solar orbits consistent with the uncertainties in the astronomical data. We find that various versions of the orbital model are not favored beyond simpler reference models. In particular, the distribution of mass extinction events can be explained just as well by a uniform random distribution as by any other model tested. Although our negative results on the orbital model are robust to changes in the Galaxy model, the Sun's coordinates, and the errors in the data, we also find that it would be very difficult to positively identify the orbital model even if it were the true one. (In contrast, we do find evidence against simpler periodic models.) Thus, while we cannot rule out there being some connection between solar motion and biodiversity variations on the Earth, we conclude that it is difficult to give convincing positive conclusions of such a connection using current data.« less

Optimization image of magnetic resonance imaging (MRI) T2 fast spin echo (FSE) with variation echo train length (ETL) on the rupture tendon achilles case

NASA Astrophysics Data System (ADS)

Muzamil, Akhmad; Haries Firmansyah, Achmad

2017-05-01

The research was done the optimization image of Magnetic Resonance Imaging (MRI) T2 Fast Spin Echo (FSE) with variation Echo Train Length (ETL) on the Rupture Tendon Achilles case. This study aims to find the variations Echo Train Length (ETL) from the results of ankle’s MRI image and find out how the value of Echo Train Length (ETL) works on the MRI ankle to produce optimal image. In this research, the used ETL variations were 12 and 20 with the interval 2 on weighting T2 FSE sagittal. The study obtained the influence of Echo Train Length (ETL) on the quality of ankle MRI image sagittal using T2 FSE weighting and analyzed in 25 images of five patients. The data analysis has done quantitatively with the Region of Interest (ROI) directly on computer MRI image planes which conducted statistical tests Signal to Noise Ratio (SNR) and Contras to Noise Ratio (CNR). The Signal to Noise Ratio (SNR) was the highest finding on fat tissue, while the Contras to Noise Ratio (CNR) on the Tendon-Fat tissue with ETL 12 found in two patients. The statistics test showed the significant SNR value of the 0.007 (p<0.05) of Tendon tissue, 0.364 (p>0.05) of the Fat, 0.912 (p>0.05) of the Fibula, and 0.436 (p>0.05) of the Heel Bone. For the contrast to noise ratio (CNR) of the Tendon-FAT tissue was about 0.041 (p>0.05). The results of the study showed that ETL variation with T2 FSE sagittal weighting had difference at Tendon tissue and Tendon-Fat tissue for MRI imaging quality. SNR and CNR were an important aspect on imaging optimization process to give the diagnose information.

Identification of Vibrotactile Patterns Encoding Obstacle Distance Information.

PubMed

Kim, Yeongmi; Harders, Matthias; Gassert, Roger

2015-01-01

Delivering distance information of nearby obstacles from sensors embedded in a white cane-in addition to the intrinsic mechanical feedback from the cane-can aid the visually impaired in ambulating independently. Haptics is a common modality for conveying such information to cane users, typically in the form of vibrotactile signals. In this context, we investigated the effect of tactile rendering methods, tactile feedback configurations and directions of tactile flow on the identification of obstacle distance. Three tactile rendering methods with temporal variation only, spatio-temporal variation and spatial/temporal/intensity variation were investigated for two vibration feedback configurations. Results showed a significant interaction between tactile rendering method and feedback configuration. Spatio-temporal variation generally resulted in high correct identification rates for both feedback configurations. In the case of the four-finger vibration, tactile rendering with spatial/temporal/intensity variation also resulted in high distance identification rate. Further, participants expressed their preference for the four-finger vibration over the single-finger vibration in a survey. Both preferred rendering methods with spatio-temporal variation and spatial/temporal/intensity variation for the four-finger vibration could convey obstacle distance information with low workload. Overall, the presented findings provide valuable insights and guidance for the design of haptic displays for electronic travel aids for the visually impaired.

Whole genome survey of coding SNPs reveals a reproducible pathway determinant of Parkinson disease

PubMed Central

Srinivasan, Balaji S; Doostzadeh, Jaleh; Absalan, Farnaz; Mohandessi, Sharareh; Jalili, Roxana; Bigdeli, Saharnaz; Wang, Justin; Mahadevan, Jaydev; Lee, Caroline LG; Davis, Ronald W; William Langston, J; Ronaghi, Mostafa

2009-01-01

It is quickly becoming apparent that situating human variation in a pathway context is crucial to understanding its phenotypic significance. Toward this end, we have developed a general method for finding pathways associated with traits that control for pathway size. We have applied this method to a new whole genome survey of coding SNP variation in 187 patients afflicted with Parkinson disease (PD) and 187 controls. We show that our dataset provides an independent replication of the axon guidance association recently reported by Lesnick et al. [PLoS Genet 2007;3:e98], and also indicates that variation in the ubiquitin-mediated proteolysis and T-cell receptor signaling pathways may predict PD susceptibility. Given this result, it is reasonable to hypothesize that pathway associations are more replicable than individual SNP associations in whole genome association studies. However, this hypothesis is complicated by a detailed comparison of our dataset to the second recent PD association study by Fung et al. [Lancet Neurol 2006;5:911–916]. Surprisingly, we find that the axon guidance pathway does not rank at the very top of the Fung dataset after controlling for pathway size. More generally, in comparing the studies, we find that SNP frequencies replicate well despite technologically different assays, but that both SNP and pathway associations are globally uncorrelated across studies. We thus have a situation in which an association between axon guidance pathway variation and PD has been found in 2 out of 3 studies. We conclude by relating this seeming inconsistency to the molecular heterogeneity of PD, and suggest future analyses that may resolve such discrepancies. PMID:18853455

Which processes drive observed variations of HCHO columns over India?

NASA Astrophysics Data System (ADS)

Surl, Luke; Palmer, Paul I.; González Abad, Gonzalo

2018-04-01

We interpret HCHO column variations observed by the Ozone Monitoring Instrument (OMI), aboard the NASA Aura satellite, over India during 2014 using the GEOS-Chem atmospheric chemistry and transport model. We use a nested version of the model with a horizontal resolution of approximately 25 km. HCHO columns are related to local emissions of volatile organic compounds (VOCs) with a spatial smearing that increases with the VOC lifetime. Over India, HCHO has biogenic, pyrogenic, and anthropogenic VOC sources. Using a 0-D photochemistry model, we find that isoprene has the largest molar yield of HCHO which is typically realized within a few hours. We also find that forested regions that neighbour major urban conurbations are exposed to high levels of nitrogen oxides. This results in depleted hydroxyl radical concentrations and a delay in the production of HCHO from isoprene oxidation. We find that propene is the only anthropogenic VOC emitted in major Indian cities that produces HCHO at a comparable (but slower) rate to isoprene. The GEOS-Chem model reproduces the broad-scale annual mean HCHO column distribution observed by OMI (r = 0.6), which is dominated by a distinctive meridional gradient in the northern half of the country, and by localized regions of high columns that coincide with forests. Major discrepancies are noted over the Indo-Gangetic Plain (IGP) and Delhi. We find that the model has more skill at reproducing observations during winter (JF) and pre-monsoon (MAM) months with Pearson correlations r > 0.5 but with a positive model bias of x≃1×1015 molec cm-2. During the monsoon season (JJAS) we reproduce only a diffuse version of the observed meridional gradient (r = 0.4). We find that on a continental scale most of the HCHO column seasonal cycle is explained by monthly variations in surface temperature (r = 0.9), suggesting a role for biogenic VOCs, in agreement with the 0-D and GEOS-Chem model calculations. We also find that the seasonal cycle during 2014 is not significantly different from the 2008 to 2015 mean seasonal variation. There are two main loci for biomass burning (the states of Punjab and Haryana, and northeastern India), which we find makes a significant contribution (up to 1×1015 molec cm-2) to observed HCHO columns only during March and April over northeastern India. The slow production of HCHO from propene oxidation results in a smeared hotspot over Delhi that we resolve only on an annual mean timescale by using a temporal oversampling method. Using a linear regression model to relate GEOS-Chem isoprene emissions to HCHO columns we infer seasonal isoprene emissions over two key forest regions from the OMI HCHO column data. We find that the a posteriori emissions are typically lower than the a priori emissions, with a much stronger reduction of emissions during the monsoon season. We find that this reduction in emissions during monsoon months coincides with a large drop in satellite observations of leaf phenology that recovers in post monsoon months. This may signal a forest-scale response to monsoon conditions.

Secular Resonances In Planetary Satellites

NASA Astrophysics Data System (ADS)

Yokoyama, T.; Marinho, E. P.

1999-09-01

Due to the tides the orbits of Phobos and Triton are spiralling in towards their host planets. On the contrary, our Moon is being driven away from the Earth. Most probably, in the past many other particles experienced similar variations. During this evolution, the semimajor axis assumes several values which can cause significant resonances, involving the node, pericenter and the longitude of the Sun. Recently Touma and Wisdom showed the decisive effect played by evection and iviction resonances in the Earth-Moon system. In this work we derive the averaged equations of a satellite disturbed by the Sun and the oblateness of the planet. Neglecting higher order (third) in the ratio of the distances, all possible resonances are studied. In general we are used to small values of the ecliptic. However in the past, the obliquity of the inner planets could have attained very high values (Laskar et all). Then taking into account large values of the obliquity we find some significant variations in the inclinations, besides others in the eccentricities. If some empirical law of the variation of the semimajor axis is assumed, then with the averaged equations we can easily see the jumps in these elements when the satellite crosses some resonance. Finally we show the possible variations in the Phobos' eccentricity since it will cross the evection resonance in the future. We also show some possible and significant resonances faced by Triton in the past. For partial financial support we thank FAPESP.

Rare copy number variations in congenital heart disease patients identify unique genes in left-right patterning

PubMed Central

Fakhro, Khalid A.; Choi, Murim; Ware, Stephanie M.; Belmont, John W.; Towbin, Jeffrey A.; Lifton, Richard P.; Khokha, Mustafa K.; Brueckner, Martina

2011-01-01

Dominant human genetic diseases that impair reproductive fitness and have high locus heterogeneity constitute a problem for gene discovery because the usual criterion of finding more mutations in specific genes than expected by chance may require extremely large populations. Heterotaxy (Htx), a congenital heart disease resulting from abnormalities in left-right (LR) body patterning, has features suggesting that many cases fall into this category. In this setting, appropriate model systems may provide a means to support implication of specific genes. By high-resolution genotyping of 262 Htx subjects and 991 controls, we identify a twofold excess of subjects with rare genic copy number variations in Htx (14.5% vs. 7.4%, P = 1.5 × 10−4). Although 7 of 45 Htx copy number variations were large chromosomal abnormalities, 38 smaller copy number variations altered a total of 61 genes, 22 of which had Xenopus orthologs. In situ hybridization identified 7 of these 22 genes with expression in the ciliated LR organizer (gastrocoel roof plate), a marked enrichment compared with 40 of 845 previously studied genes (sevenfold enrichment, P < 10−6). Morpholino knockdown in Xenopus of Htx candidates demonstrated that five (NEK2, ROCK2, TGFBR2, GALNT11, and NUP188) strongly disrupted both morphological LR development and expression of pitx2, a molecular marker of LR patterning. These effects were specific, because 0 of 13 control genes from rare Htx or control copy number variations produced significant LR abnormalities (P = 0.001). These findings identify genes not previously implicated in LR patterning. PMID:21282601

Rare copy number variations in congenital heart disease patients identify unique genes in left-right patterning.

PubMed

Fakhro, Khalid A; Choi, Murim; Ware, Stephanie M; Belmont, John W; Towbin, Jeffrey A; Lifton, Richard P; Khokha, Mustafa K; Brueckner, Martina

2011-02-15

Dominant human genetic diseases that impair reproductive fitness and have high locus heterogeneity constitute a problem for gene discovery because the usual criterion of finding more mutations in specific genes than expected by chance may require extremely large populations. Heterotaxy (Htx), a congenital heart disease resulting from abnormalities in left-right (LR) body patterning, has features suggesting that many cases fall into this category. In this setting, appropriate model systems may provide a means to support implication of specific genes. By high-resolution genotyping of 262 Htx subjects and 991 controls, we identify a twofold excess of subjects with rare genic copy number variations in Htx (14.5% vs. 7.4%, P = 1.5 × 10(-4)). Although 7 of 45 Htx copy number variations were large chromosomal abnormalities, 38 smaller copy number variations altered a total of 61 genes, 22 of which had Xenopus orthologs. In situ hybridization identified 7 of these 22 genes with expression in the ciliated LR organizer (gastrocoel roof plate), a marked enrichment compared with 40 of 845 previously studied genes (sevenfold enrichment, P < 10(-6)). Morpholino knockdown in Xenopus of Htx candidates demonstrated that five (NEK2, ROCK2, TGFBR2, GALNT11, and NUP188) strongly disrupted both morphological LR development and expression of pitx2, a molecular marker of LR patterning. These effects were specific, because 0 of 13 control genes from rare Htx or control copy number variations produced significant LR abnormalities (P = 0.001). These findings identify genes not previously implicated in LR patterning.

A Quantitative Comparison of the Similarity between Genes and Geography in Worldwide Human Populations

PubMed Central

Wang, Chaolong; Zöllner, Sebastian; Rosenberg, Noah A.

2012-01-01

Multivariate statistical techniques such as principal components analysis (PCA) and multidimensional scaling (MDS) have been widely used to summarize the structure of human genetic variation, often in easily visualized two-dimensional maps. Many recent studies have reported similarity between geographic maps of population locations and MDS or PCA maps of genetic variation inferred from single-nucleotide polymorphisms (SNPs). However, this similarity has been evident primarily in a qualitative sense; and, because different multivariate techniques and marker sets have been used in different studies, it has not been possible to formally compare genetic variation datasets in terms of their levels of similarity with geography. In this study, using genome-wide SNP data from 128 populations worldwide, we perform a systematic analysis to quantitatively evaluate the similarity of genes and geography in different geographic regions. For each of a series of regions, we apply a Procrustes analysis approach to find an optimal transformation that maximizes the similarity between PCA maps of genetic variation and geographic maps of population locations. We consider examples in Europe, Sub-Saharan Africa, Asia, East Asia, and Central/South Asia, as well as in a worldwide sample, finding that significant similarity between genes and geography exists in general at different geographic levels. The similarity is highest in our examples for Asia and, once highly distinctive populations have been removed, Sub-Saharan Africa. Our results provide a quantitative assessment of the geographic structure of human genetic variation worldwide, supporting the view that geography plays a strong role in giving rise to human population structure. PMID:22927824

The Effect of Common Inversion Polymorphisms In(2L)t and In(3R)Mo on Patterns of Transcriptional Variation in Drosophila melanogaster.

PubMed

Lavington, Erik; Kern, Andrew D

2017-11-06

Chromosomal inversions are a ubiquitous feature of genetic variation. Theoretical models describe several mechanisms by which inversions can drive adaptation and be maintained as polymorphisms. While inversions have been shown previously to be under selection, or contain genetic variation under selection, the specific phenotypic consequences of inversions leading to their maintenance remain unclear. Here we use genomic sequence and expression data from the Drosophila Genetic Reference Panel (DGRP) to explore the effects of two cosmopolitan inversions, In ( 2L ) t and In ( 3R ) Mo , on patterns of transcriptional variation. We demonstrate that each inversion has a significant effect on transcript abundance for hundreds of genes across the genome. Inversion-affected loci (IAL) appear both within inversions as well as on unlinked chromosomes. Importantly, IAL do not appear to be influenced by the previously reported genome-wide expression correlation structure. We found that five genes involved with sterol uptake, four of which are Niemann-Pick Type 2 orthologs, are upregulated in flies with In ( 3R ) Mo but do not have SNPs in linkage disequilibrium (LD) with the inversion. We speculate that this upregulation is driven by genetic variation in mod ( mdg4 ) that is in LD with In ( 3R ) Mo We find that there is little evidence for a regional or position effect of inversions on gene expression at the chromosomal level, but do find evidence for the distal breakpoint of In ( 3R ) Mo interrupting one gene and possibly disassociating the two flanking genes from regulatory elements. Copyright © 2017 Lavington and Kern.

The Effect of Common Inversion Polymorphisms In(2L)t and In(3R)Mo on Patterns of Transcriptional Variation in Drosophila melanogaster

PubMed Central

Lavington, Erik; Kern, Andrew D.

2017-01-01

Chromosomal inversions are a ubiquitous feature of genetic variation. Theoretical models describe several mechanisms by which inversions can drive adaptation and be maintained as polymorphisms. While inversions have been shown previously to be under selection, or contain genetic variation under selection, the specific phenotypic consequences of inversions leading to their maintenance remain unclear. Here we use genomic sequence and expression data from the Drosophila Genetic Reference Panel (DGRP) to explore the effects of two cosmopolitan inversions, In(2L)t and In(3R)Mo, on patterns of transcriptional variation. We demonstrate that each inversion has a significant effect on transcript abundance for hundreds of genes across the genome. Inversion-affected loci (IAL) appear both within inversions as well as on unlinked chromosomes. Importantly, IAL do not appear to be influenced by the previously reported genome-wide expression correlation structure. We found that five genes involved with sterol uptake, four of which are Niemann-Pick Type 2 orthologs, are upregulated in flies with In(3R)Mo but do not have SNPs in linkage disequilibrium (LD) with the inversion. We speculate that this upregulation is driven by genetic variation in mod(mdg4) that is in LD with In(3R)Mo. We find that there is little evidence for a regional or position effect of inversions on gene expression at the chromosomal level, but do find evidence for the distal breakpoint of In(3R)Mo interrupting one gene and possibly disassociating the two flanking genes from regulatory elements. PMID:28916647

A quantitative comparison of the similarity between genes and geography in worldwide human populations.

PubMed

Wang, Chaolong; Zöllner, Sebastian; Rosenberg, Noah A

2012-08-01

Multivariate statistical techniques such as principal components analysis (PCA) and multidimensional scaling (MDS) have been widely used to summarize the structure of human genetic variation, often in easily visualized two-dimensional maps. Many recent studies have reported similarity between geographic maps of population locations and MDS or PCA maps of genetic variation inferred from single-nucleotide polymorphisms (SNPs). However, this similarity has been evident primarily in a qualitative sense; and, because different multivariate techniques and marker sets have been used in different studies, it has not been possible to formally compare genetic variation datasets in terms of their levels of similarity with geography. In this study, using genome-wide SNP data from 128 populations worldwide, we perform a systematic analysis to quantitatively evaluate the similarity of genes and geography in different geographic regions. For each of a series of regions, we apply a Procrustes analysis approach to find an optimal transformation that maximizes the similarity between PCA maps of genetic variation and geographic maps of population locations. We consider examples in Europe, Sub-Saharan Africa, Asia, East Asia, and Central/South Asia, as well as in a worldwide sample, finding that significant similarity between genes and geography exists in general at different geographic levels. The similarity is highest in our examples for Asia and, once highly distinctive populations have been removed, Sub-Saharan Africa. Our results provide a quantitative assessment of the geographic structure of human genetic variation worldwide, supporting the view that geography plays a strong role in giving rise to human population structure.

Antimicrobial proteins in human unstimulated whole saliva in relation to each other, and to measures of health status, dental plaque accumulation and composition.

PubMed

Rudney, J D; Krig, M A; Neuvar, E K; Soberay, A H; Iverson, L

1991-01-01

Saliva antimicrobial proteins may interact in a common system to influence the oral ecology. Clinical studies of antimicrobial protein action thus may require a multiple-protein approach. Multivariate statistical methods have been used to describe possible patterns of interaction for lysozyme, lactoferrin, salivary peroxidase and secretory IgA in stimulated parotid saliva. However, oral microbes are most likely to encounter antimicrobial proteins in mixed resting saliva. Relationships among levels of lysozyme, lactoferrin, salivary peroxidase, and secretory IgA therefore were investigated in whole saliva from 216 subjects, and an attempt made to relate interperson variation in those proteins to differences in health and status, and dental plaque accumulation and composition. All proteins were significantly (alpha = 0.05) correlated with each other (r = 0.38-0.52, p less than 0.001). There was only one axis of common variation among proteins, and that axis was significantly correlated (p less than 0.001) with total protein (r = 0.84) and flow rate (r = -0.56). That pattern deviated from the previous finding that proteins of acinar origin tended to vary independently from proteins of ductal origin in stimulated parotid saliva. The difference between parotid and whole saliva may reflect constitutive secretion of all proteins at low levels of stimulation. Common variation of unstimulated saliva proteins suggests that antimicrobial actions can be compared in subjects at population extremes. There were no significant associations between antimicrobial proteins in whole saliva and measures of health status or plaque accumulation. However, the proportions of Streptococcus sanguis were significantly correlated with lysozyme (r = -0.26), lactoferrin (r = -0.34), peroxidase (r = -0.30), total protein (r = -0.37), flow rate (r = 0.24) and principal-components scores (r = -0.33) in a subset of subjects (n = 85) where commercial biochemical tests were used to supplement species identification by colony morphology. Those findings may indicate that saliva antimicrobial proteins can affect the composition of dental plaque.

Postpollination discrimination between self and outcross pollen covaries with the mating system of a self-compatible flowering plant.

PubMed

Cruzan, Mitchell B; Barrett, Spencer C H

2016-03-01

Variation in the mating system of hermaphroditic plant populations is determined by interactions between genetic and environmental factors operating via both pre- and postmating processes. Models predicting the maintenance of intermediate outcrossing rates in animal-pollinated plants often assume that the mating system is primarily controlled by floral morphology and pollinator availability, but rarely has the influence of postpollination processes on variation in outcrossing been examined. We investigated the influence of stylar discrimination between illegitimate and legitimate pollen-tube growth and the pollen-load capacity of stigmas on mating-system variation in the annual, tristylous species Eichhornia paniculata using controlled crosses and genetic markers. This species exhibits an exceptionally broad range of outcrossing rates in natural populations. There was significant variation among populations in the pollen-load capacity of stigmas and the ability of styles to discriminate between illegitimate vs. legitimate pollen. There was strong correspondence between stylar-discrimination ability and variation in outcrossing rate among populations and style morphs. The combination of stigmatic pollen-load capacity and stylar discrimination explained more than 80% of the variation in outcrossing rates among populations. The finding that stigmatic pollen-load capacity and stylar-discrimination ability contributed significantly to explaining the wide range of outcrossing rates in E. paniculata suggests that postpollination mechanisms play an important role in governing mating patterns in this species. The difference in levels of stylar discrimination between outcrossing and selfing populations may reflect a trade-off between selection for increased outcrossing and greater reproductive assurance. © 2016 Botanical Society of America.

Magnetic resonance imaging of the calcaneus: preliminary assessment of trabecular bone-dependent regional variations in marrow relaxation time compared with dual X-ray absorptiometry

NASA Technical Reports Server (NTRS)

Guglielmi, G.; Selby, K.; Blunt, B. A.; Jergas, M.; Newitt, D. C.; Genant, H. K.; Majumdar, S.

1996-01-01

RATIONALE AND OBJECTIVES: Marrow transverse relaxation time (T2*) in magnetic resonance (MR) imaging may be related to the density and structure of the surrounding trabecular network. We investigated regional variations of T2* in the human calcaneus and compared the findings with bone mineral density (BMD), as measured by dual X-ray absorpiometry (DXA). Short- and long-term precisions were evaluated first to determine whether MR imaging would be useful for the clinical assessment of disease status and progression in osteoporosis. METHODS: Gradient-recalled echo MR images of the calcaneus were acquired at 1.5 T from six volunteers. Measurements of T2* were compared with BMD and (for one volunteer) conventional radiography. RESULTS: T2* values showed significant regional variation; they typically were shortest in the superior region of the calcaneus. There was a linear correlation between MR and DXA measurements (r = .66 for 1/T2* versus BMD). Differences in T2* attributable to variations in analysis region-of-interest placement were not significant for five of the six volunteers. Sagittal MR images had short- and long-term precision errors of 4.2% and 3.3%, respectively. For DXA, the precision was 1.3% (coefficient of variation). CONCLUSION: MR imaging may be useful for trabecular bone assessment in the calcaneus. However, given the large regional variations in bone density and structure, the choice of an ROI is likely to play a major role in the accuracy, precision, and overall clinical efficacy of T2* measurements.

TEMPORAL STABILITY OF SUNSPOT UMBRAL INTENSITIES: 1986-2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Toma, G.; Chapman, G. A.; Cookson, A. M.

2013-07-10

We examine the relative intensity of sunspot umbrae during the period from 1986 to 2012 using photometric images from the San Fernando Observatory. We confirm the presence of a relationship between the mean umbral core intensity and the mean sunspot area, as found in previous studies, and do not find a notable change in this relationship between cycles 22 and 23. We looked for a possible time variation in the sunspot umbral contrast during the 27 yr covering cycles 22, 23, and the rise of cycle 24, and we did not find a significant change. These findings do not indicatemore » that sunspots have become less dark during cycles 23 and 24.« less

Impact of seasonal variation, age and smoking status on human semen parameters: The Massachusetts General Hospital experience

PubMed Central

Chen, Zuying; Godfrey-Bailey, Linda; Schiff, Isaac; Hauser, Russ

2004-01-01

Background To investigate the relationship of human semen parameters with season, age and smoking status. Methods The present study used data from subjects recruited into an ongoing cross-sectional study on the relationship between environmental agents and semen characteristics. Our population consisted of 306 patients who presented to the Vincent Memorial Andrology Laboratory of Massachusetts General Hospital for semen evaluation. Sperm concentration and motility were measured with computer aided sperm analysis (CASA). Sperm morphology was scored using Tygerberg Kruger strict criteria. Regression analyses were used to investigate the relationships between semen parameters and season, age and smoking status, adjusting for abstinence interval. Results Sperm concentration in the spring was significantly higher than in winter, fall and summer (p < 0.05). There was suggestive evidence of higher sperm motility and percent of sperm with normal morphology in the spring than in the other seasons. There were no statistically significant relationships between semen parameters and smoking status, though current smokers tended to have lower sperm concentration. We also did not find a statistically significant relationship between age and semen parameters. Conclusions We found seasonal variations in sperm concentration and suggestive evidence of seasonal variation in sperm motility and percent sperm with normal morphology. Although smoking status was not a significant predictor of semen parameters, this may have been due to the small number of current smokers in the study. PMID:15507127

Racial variations in booking haemoglobin of primigravidae in Malaysia: a prospective study

PubMed Central

2013-01-01

Background Variations in racial haemoglobin had been previously described in multiple studies locally and abroad. This study was conducted to quantify the differences in haemoglobin of booking primigravidae amongst the three major races in Malaysia at the antenatal clinic of University Malaya Medical Centre, Kuala Lumpur. Findings One year prospective study of booking full blood count sample of primigravidae taken in one centre was conducted. Multiple comparative analyses of the booking haemoglobin were performed using the One-way ANOVA comparative mean test in each trimester. 622 primigravidae without any known history of haematological disorders were recruited into the study. The mean haemoglobin for the Indian race was the lowest compared to the two other races in the second and the third trimesters, and it was found to be statistically significant lower (p- value 0.001) than the Malay race in the second trimester. It was also found that the Indian race had a significantly higher incidence of moderate to severe anaemia (p- value: 0.029). The prevalence of anaemia in our study population is also significantly higher in the Indian population (p- value: 0.01). Conclusions The findings from this study have established that there is racial preponderance to anaemia in pregnancy. The Indian race is at a higher risk of having anaemia in pregnancy particularly in the second trimester. PMID:23634656

The use of biocultural data in interpreting sex differences in body proportions among rural Amazonians

PubMed Central

VERCELLOTTI, GIUSEPPE; PIPERATA, BARBARA A.

2012-01-01

Variation in height and body proportions is relatively well understood at the inter-population level, but less is known about intra-population variation. This study explores intra-population variation in body proportions among 172 (88 female; 84 male) adult rural Amazonians. We test the hypotheses that: 1) stunting is associated with changes in proportions and fatness; 2) the sexes express different proportions in response to similar environmental stress and 3) female growth is negatively affected by the costs of reproduction. We examined height, sitting height and total leg length in subsamples based on sex and nutritional status (stunted/non-stunted) in relation to biocultural factors including access to food and healthcare and female reproductive history parameters. Differences in proportions were examined using the Quick-Test (Tsutakawa and Hewett, 1977); correlation analyses were employed to detect associations between anthropometric data and body fatness, and female reproductive history parameters. We found significantly higher rates of stunting among females (X2=5.31; p=0.02; RR=1.4). Stunted individuals exhibited relatively shorter legs than non-stunted individuals (p=0.02), although this was not found in within-sex analyses. A significant negative correlation was found between leg length index and fatness (p<0.01). Lastly, females exhibited relatively shorter legs than males (p=0.0003) and, among females, height and leg length were significantly positively correlated with age-at-first-birth (p<0.02) suggesting that adolescent pregnancy may negatively affect growth in this population. Our findings provide insights for the study of intra-population variation in body proportions and highlight the importance of biocultural data in interpreting the pattern of variation observed in living and past populations. PMID:22120650

The use of biocultural data in interpreting sex differences in body proportions among rural Amazonians.

PubMed

Vercellotti, Giuseppe; Piperata, Barbara A

2012-01-01

Variation in height and body proportions is relatively well-understood at the inter-population level, but less is known about intra-population variation. This study explores intra-population variation in body proportions among 172 (88 female; 84 male) adult rural Amazonians. We test the hypotheses that: (1) stunting is associated with changes in proportions and fatness; (2) the sexes express different proportions in response to similar environmental stress; and (3) female growth is negatively affected by the costs of reproduction. We examined height, sitting height, and total leg length in subsamples based on sex and nutritional status (stunted/nonstunted) in relation to biocultural factors including access to food and healthcare and female reproductive history parameters. Differences in proportions were examined using the Quick-Test (Tsutakawa and Hewett: Biometrics 33 (1977) 215-219); correlation analyses were used to detect associations between anthropometric data and body fatness, and female reproductive history parameters. We found significantly higher rates of stunting among females (X(2) = 5.31; P = 0.02; RR = 1.4). Stunted individuals exhibited relatively shorter legs than nonstunted individuals (P = 0.02), although this was not found in within-sex analyses. A significant negative correlation was found between leg length index and fatness (P < 0.01). Lastly, females exhibited relatively shorter legs than males (P = 0.0003) and, among females, height and leg length were significantly positively correlated with age-at-first-birth (P < 0.02) suggesting that adolescent pregnancy may negatively affect growth in this population. Our findings provide insights for the study of intra-population variation in body proportions and highlight the importance of biocultural data in interpreting the pattern of variation observed in living and past populations. Copyright © 2011 Wiley Periodicals, Inc.

[Variation of CAG repeats in coding region of ATXN2 gene in different ethnic groups].

PubMed

Chen, Xiao-Chen; Sun, Hao; Mi, Dong-Qing; Huang, Xiao-Qin; Lin, Ke-Qin; Yi, Wen; Yu, Liang; Shi, Lei; Shi, Li; Yang, Zhao-Qing; Chu, Jia-You

2011-04-01

Toinvestigate CAG repeats variation of ATXN2 gene coding region in six ethnic groups that live in comparatively different environments, to evaluate whether these variations are under positive selection, and to find factors driving selection effects, 291 unrelated healthy individuals were collected from six ethnic groups and their STR geneotyping was performed. The frequencies of alleles and genotypes were counted and thereby Slatkin's linearized Fst values were calculated. The UPGMA tree against this gene was constructed. The MDS analysis among these groups was carried out as well. The results from the linearized Fst values indicated that there were significant evolutionary differences of the STR in ATXN2 gene between Hui and Yi groups, but not among the other 4 groups. Further analysis was performed by combining our data with published data obtained from other groups. These results indicated that there were significant differences between Japanese and other groups including Hui, Hani, Yunnan Mongolian, and Inner Mongolian. Both Hui and Mongolian from Inner Mongolia were significantly different from Han. In conclusion, the six ethnic groups had their own distribution characterizations of allelic frequencies of ATXN2 STR, and the potential cause of frequency changes in rare alleles could be the consequence of positive selection.

Shape and size variation on the wing of Drosophila mediopunctata: influence of chromosome inversions and genotype-environment interaction.

PubMed

Hatadani, Luciane Mendes; Klaczko, Louis Bernard

2008-07-01

The second chromosome of Drosophila mediopunctata is highly polymorphic for inversions. Previous work reported a significant interaction between these inversions and collecting date on wing size, suggesting the presence of genotype-environment interaction. We performed experiments in the laboratory to test for the joint effects of temperature and chromosome inversions on size and shape of the wing in D. mediopunctata. Size was measured as the centroid size, and shape was analyzed using the generalized least squares Procrustes superimposition followed by discriminant analysis and canonical variates analysis of partial warps and uniform components scores. Our findings show that wing size and shape are influenced by temperature, sex, and karyotype. We also found evidence suggestive of an interaction between the effects of karyotype and temperature on wing shape, indicating the existence of genotype-environment interaction for this trait in D. mediopunctata. In addition, the association between wing size and chromosome inversions is in agreement with previous results indicating that these inversions might be accumulating alleles adapted to different temperatures. However, no significant interaction between temperature and karyotype for size was found--in spite of the significant presence of temperature-genotype (cross) interaction. We suggest that other ecological factors--such as larval crowding--or seasonal variation of genetic content within inversions may explain the previous results.

Diurnal Variations in Global Joule Heating Morphology and Magnitude Due To Neutral Winds

NASA Astrophysics Data System (ADS)

Billett, D. D.; Grocott, A.; Wild, J. A.; Walach, M.-T.; Kosch, M. J.

2018-03-01

In the polar ionosphere, variations in Joule heating are significantly controlled by changes in plasma convection, such as that brought about by changes in the interplanetary magnetic field. However, another important consideration when calculating Joule heating is the velocity difference between this plasma and the neutral thermosphere colocated with the ionosphere. Neutral wind data are often difficult to obtain on a global scale; thus, Joule heating has often previously been calculated assuming that neutral velocities are small and can therefore be neglected. Previous work has shown the effect of neutral winds on Joule heating estimations to be more significant than originally thought; however, the diurnal variations of the neutrals due to changes in solar pressure gradients and Coriolis forces have yet to have their impact on Joule heating assessed. We show this universal time effect to be significant in calculating Joule heating and thus can differ significantly from that calculated by neglecting the neutrals. In this study, we use empirical models for the neutral wind, conductivities, and magnetic field to create Northern Hemispheric patterns of Joule heating for approximately 800,000 individual plasma convection patterns generated using data from the Super Dual Auroral Radar Network. From this, a statistical analysis of how Joule heating varies in morphology and magnitude with universal time is shown for differing seasons and levels of geomagnetic activity. We find that neutral winds do play a significant role in the morphology and total energy output of Joule heating.

A Comparative Analysis of a Game-Based Mobile Learning Model in Low-Socioeconomic Communities of India

ERIC Educational Resources Information Center

Kim, Paul; Buckner, Elizabeth; Kim, Hyunkyung; Makany, Tamas; Taleja, Neha; Parikh, Vallabhi

2012-01-01

This study explores the effectiveness of a game-based mobile learning model for children living in underdeveloped regions with significant contextual variations. Data for this study came from a total of 210 children between the ages of 6-14 years old from six marginalized communities in India. The findings reveal that children with little or no…

From Natural Variation to Optimal Policy? The Lucas Critique Meets Peer Effects. NBER Working Paper No. 16865

ERIC Educational Resources Information Center

Carrell, Scott E.; Sacerdote, Bruce I.; West, James E.

2011-01-01

We take cohorts of entering freshmen at the United States Air Force Academy and assign half to peer groups with the goal of maximizing the academic performance of the lowest ability students. Our assignment algorithm uses peer effects estimates from the observational data. We find a negative and significant treatment effect for the students we…

Y-Chromosome Variation in Hominids: Intraspecific Variation Is Limited to the Polygamous Chimpanzee

PubMed Central

Greve, Gabriele; Alechine, Evguenia; Pasantes, Juan J.; Hodler, Christine; Rietschel, Wolfram; Robinson, Terence J.; Schempp, Werner

2011-01-01

Background We have previously demonstrated that the Y-specific ampliconic fertility genes DAZ (deleted in azoospermia) and CDY (chromodomain protein Y) varied with respect to copy number and position among chimpanzees (Pan troglodytes). In comparison, seven Y-chromosomal lineages of the bonobo (Pan paniscus), the chimpanzee's closest living relative, showed no variation. We extend our earlier comparative investigation to include an analysis of the intraspecific variation of these genes in gorillas (Gorilla gorilla) and orangutans (Pongo pygmaeus), and examine the resulting patterns in the light of the species' markedly different social and mating behaviors. Methodology/Principal Findings Fluorescence in situ hybridization analysis (FISH) of DAZ and CDY in 12 Y-chromosomal lineages of western lowland gorilla (G. gorilla gorilla) and a single lineage of the eastern lowland gorilla (G. beringei graueri) showed no variation among lineages. Similar findings were noted for the 10 Y-chromosomal lineages examined in the Bornean orangutan (Pongo pygmaeus), and 11 Y-chromosomal lineages of the Sumatran orangutan (P. abelii). We validated the contrasting DAZ and CDY patterns using quantitative real-time polymerase chain reaction (qPCR) in chimpanzee and bonobo. Conclusion/Significance High intraspecific variation in copy number and position of the DAZ and CDY genes is seen only in the chimpanzee. We hypothesize that this is best explained by sperm competition that results in the variant DAZ and CDY haplotypes detected in this species. In contrast, bonobos, gorillas and orangutans—species that are not subject to sperm competition—showed no intraspecific variation in DAZ and CDY suggesting that monoandry in gorillas, and preferential female mate choice in bonobos and orangutans, probably permitted the fixation of a single Y variant in each taxon. These data support the notion that the evolutionary history of a primate Y chromosome is not simply encrypted in its DNA sequences, but is also shaped by the social and behavioral circumstances under which the specific species has evolved. PMID:22216243

Dental Care Utilization for Examination and Regional Deprivation

PubMed Central

Kim, Cheol-Sin; Han, Sun-Young; Lee, Seung Eun; Kang, Jeong-Hee; Kim, Chul-Woung

2015-01-01

Objectives: Receiving proper dental care plays a significant role in maintaining good oral health. We investigated the relationship between regional deprivation and dental care utilization. Methods: Multilevel logistic regression was used to identify the relationship between the regional deprivation level and dental care utilization purpose, adjusting for individual-level variables, in adults aged 19+ in the 2008 Korean Community Health Survey (n=220 258). Results: Among Korean adults, 12.8% used dental care to undergo examination and 21.0% visited a dentist for other reasons. In the final model, regional deprivation level was associated with significant variations in dental care utilization for examination (p<0.001). However, this relationship was not shown with dental care utilization for other reasons in the final model. Conclusions: This study’s findings suggest that policy interventions should be considered to reduce regional variations in rates of dental care utilization for examination. PMID:26265665

Genome-wide association and linkage identify modifier loci of lung disease severity in cystic fibrosis at 11p13 and 20q13.2

PubMed Central

Wright, Fred A.; Strug, Lisa J.; Doshi, Vishal K.; Commander, Clayton W.; Blackman, Scott M.; Sun, Lei; Berthiaume, Yves; Cutler, David; Cojocaru, Andreea; Collaco, J. Michael; Corey, Mary; Dorfman, Ruslan; Goddard, Katrina; Green, Deanna; Kent, Jack W.; Lange, Ethan M.; Lee, Seunggeun; Li, Weili; Luo, Jingchun; Mayhew, Gregory M.; Naughton, Kathleen M.; Pace, Rhonda G.; Paré, Peter; Rommens, Johanna M.; Sandford, Andrew; Stonebraker, Jaclyn R.; Sun, Wei; Taylor, Chelsea; Vanscoy, Lori L.; Zou, Fei; Blangero, John; Zielenski, Julian; O’Neal, Wanda K.; Drumm, Mitchell L.; Durie, Peter R.; Knowles, Michael R.; Cutting, Garry R.

2012-01-01

A combined genome-wide association and linkage study was used to identify loci causing variation in CF lung disease severity. A significant association (P=3. 34 × 10-8) near EHF and APIP (chr11p13) was identified in F508del homozygotes (n=1,978). The association replicated in F508del homozygotes (P=0.006) from a separate family-based study (n=557), with P=1.49 × 10-9 for the three-study joint meta-analysis. Linkage analysis of 486 sibling pairs from the family-based study identified a significant QTL on chromosome 20q13.2 (LOD=5.03). Our findings provide insight into the causes of variation in lung disease severity in CF and suggest new therapeutic targets for this life-limiting disorder. PMID:21602797

Measuring the mechanical properties of molecular conformers

NASA Astrophysics Data System (ADS)

Jarvis, S. P.; Taylor, S.; Baran, J. D.; Champness, N. R.; Larsson, J. A.; Moriarty, P.

2015-09-01

Scanning probe-actuated single molecule manipulation has proven to be an exceptionally powerful tool for the systematic atomic-scale interrogation of molecular adsorbates. To date, however, the extent to which molecular conformation affects the force required to push or pull a single molecule has not been explored. Here we probe the mechanochemical response of two tetra(4-bromophenyl)porphyrin conformers using non-contact atomic force microscopy where we find a large difference between the lateral forces required for manipulation. Remarkably, despite sharing very similar adsorption characteristics, variations in the potential energy surface are capable of prohibiting probe-induced positioning of one conformer, while simultaneously permitting manipulation of the alternative conformational form. Our results are interpreted in the context of dispersion-corrected density functional theory calculations which reveal significant differences in the diffusion barriers for each conformer. These results demonstrate that conformational variation significantly modifies the mechanical response of even simple porpyhrins, potentially affecting many other flexible molecules.

Parent Report of Community Psychiatric Comorbid Diagnoses in Autism Spectrum Disorders

PubMed Central

Rosenberg, Rebecca E.; Kaufmann, Walter E.; Law, J. Kiely; Law, Paul A.

2011-01-01

We used a national online registry to examine variation in cumulative prevalence of community diagnosis of psychiatric comorbidity in 4343 children with autism spectrum disorders (ASD). Adjusted multivariate logistic regression models compared influence of individual, family, and geographic factors on cumulative prevalence of parent-reported anxiety disorder, depression, bipolar disorder, and attention deficit/hyperactivity disorder or attention deficit disorder. Adjusted odds of community-assigned lifetime psychiatric comorbidity were significantly higher with each additional year of life, with increasing autism severity, and with Asperger syndrome and pervasive developmental disorder—not otherwise specified compared with autistic disorder. Overall, in this largest study of parent-reported community diagnoses of psychiatric comorbidity, gender, autistic regression, autism severity, and type of ASD all emerged as significant factors correlating with cumulative prevalence. These findings could suggest both underlying trends in actual comorbidity as well as variation in community interpretation and application of comorbid diagnoses in ASD. PMID:22937248

DESIGN AND TEST OF AN INSTRUMENT FOR MEASURING MICROTHERMAL SEEING ON THE MAGDALENA RIDGE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jorgensen, A. M.; Klinglesmith, D. A.; Speights, J.

2009-05-15

We have constructed and operated an automated instrument for measuring ground-level microthermal seeing at the Magdalena Ridge Observatory (MRO). The MRO is located at an altitude of 10500' in the Cibola National Forest in New Mexico, USA. It is the planned site for the MRO Optical Interferometer (MROI) planned for up to 10 collecting elements, each with a diameter of 1.4 m, and baselines eventually up to approximately 400 m. As part of the preparation for construction we deployed a system to characterize the ground-level seeing across the observatory site. The instrument is built largely of off-the-shelf components, with onlymore » the sensor head and power supply requiring electronic board assembly. Even in those cases the board architecture is very simple. The first proof-of-concept system was deployed for several weeks in the autumn of 2004, and has since undergone several iterations. The latest configuration operates entirely off batteries, incorporates wireless data acquisition, and is thus able to operate in an area with no shelter, power, or communications. In this paper we present the design of the instrument, and show initial data. The microthermal tower has four sensor pairs at heights from 0.8 to 4.41 m, significantly lower than other microthermal experiments, because of the need to characterize the seeing near the ground. We find significant variation in the contribution of this range of heights to the seeing, contributing up to 0.''3 of the seeing at some times and only 0.''02 at other times. The individual sensor power spectra have a slope in the range of 1.4--1.5, which is lower than the 1.67 slope predicted by Kolmogorov turbulence theory. We measure the well known effect of improved seeing immediately around sunset. While we find significant variation in the microthermal seeing, we did not find a pattern of corresponding variations in weather conditions, suggesting that a complicated set of factors control microthermal turbulence.« less

Contrasting effects of landscape features on genetic structure in different geographic regions in the ornate dragon lizard, Ctenophorus ornatus.

PubMed

Levy, Esther; Tomkins, Joseph L; Lebas, Natasha R; Kennington, W Jason

2013-08-01

Habitat fragmentation can have profound effects on the distribution of genetic variation within and between populations. Previously, we showed that in the ornate dragon lizard, Ctenophorus ornatus, lizards residing on outcrops that are separated by cleared agricultural land are significantly more isolated and hold less genetic variation than lizards residing on neighbouring outcrops connected by undisturbed native vegetation. Here, we extend the fine-scale study to examine the pattern of genetic variation and population structure across the species' range. Using a landscape genetics approach, we test whether land clearing for agricultural purposes has affected the population structure of the ornate dragon lizard. We found significant genetic differentiation between outcrop populations (FST  = 0.12), as well as isolation by distance within each geographic region. In support of our previous study, land clearing was associated with higher genetic divergences between outcrops and lower genetic variation within outcrops, but only in the region that had been exposed to intense agriculture for the longest period of time. No other landscape features influenced population structure in any geographic region. These results show that the effects of landscape features can vary across species' ranges and suggest there may be a temporal lag in response to contemporary changes in land use. These findings therefore highlight the need for caution when assessing the impact of contemporary land use practices on genetic variation and population structure. © 2013 John Wiley & Sons Ltd.

Temporal variations in a phytoplankton community in a subtropical reservoir: An interplay of extrinsic and intrinsic community effects.

PubMed

Yang, Wen; Zheng, Zhongming; Zheng, Cheng; Lu, Kaihong; Ding, Dewen; Zhu, Jinyong

2018-01-15

The phytoplankton community structure is potentially influenced by both extrinsic effects originating from the surrounding environment and intrinsic effects relying on interspecific interactions between two species. However, few studies have simultaneously considered both types of effects and assessed the relative importance of these factors. In this study, we used data collected over nine months (August 2012-May 2013) from a typical subtropical reservoir in southeast China to analyze the temporal variation of its phytoplankton community structure and develop a quantitative understanding of the extrinsic and intrinsic effects on phytoplankton community dynamics. Significant temporal variations were observed in environmental variables as well as the phytoplankton and zooplankton communities, whereas their variational trajectories and directions were entirely different. Variance partitioning analysis showed that extrinsic factors significantly explained only 31% of the variation in the phytoplankton community, thus suggesting that these factors were incomplete predictors of the community structure. Random forest-based models showed that 48% of qualified responsible phytoplankton species were more accurately predicted by phytoplankton-only models, which revealed clear effects of interspecific species-to-species interactions. Furthermore, we used association networks to model the interactions among phytoplankton, zooplankton and the environment. Network comparisons indicated that interspecific interactions were widely present in the phytoplankton community and dominated the network rather than those between phytoplankton and extrinsic factors. These findings expand the current understanding of the underlying mechanisms that govern phytoplankton community dynamics. Copyright © 2017 Elsevier B.V. All rights reserved.

Long-term persistence of solar activity. [Abstract only

NASA Technical Reports Server (NTRS)

Ruzmaikin, Alexander; Feynman, Joan; Robinson, Paul

1994-01-01

The solar irradiance has been found to change by 0.1% over the recent solar cycle. A change of irradiance of about 0.5% is required to effect the Earth's climate. How frequently can a variation of this size be expected? We examine the question of the persistence of non-periodic variations in solar activity. The Huerst exponent, which characterizes the persistence of a time series (Mandelbrot and Wallis, 1969), is evaluated for the series of C-14 data for the time interval from about 6000 BC to 1950 AD (Stuiver and Pearson, 1986). We find a constant Huerst exponent, suggesting that solar activity in the frequency range of from 100 to 3000 years includes an important continuum component in addition to the well-known periodic variations. The value we calculate, H approximately equal to 0.8, is significantly larger than the value of 0.5 that would correspond to variations produced by a white-noise process. This value is in good agreement with the results for the monthly sunspot data reported elsewhere, indicating that the physics that produces the continuum is a correlated random process (Ruzmaikin et al., 1992), and that is is the same type of process over a wide range of time interval lengths. We conclude that the time period over which an irradiance change of 0.5% can be expected to occur is significantly shorter than that which would be expected for variations produced by a white-noise process.

Simple Sequence Repeats Provide a Substrate for Phenotypic Variation in the Neurospora crassa Circadian Clock

PubMed Central

Michael, Todd P.; Park, Sohyun; Kim, Tae-Sung; Booth, Jim; Byer, Amanda; Sun, Qi; Chory, Joanne; Lee, Kwangwon

2007-01-01

Background WHITE COLLAR-1 (WC-1) mediates interactions between the circadian clock and the environment by acting as both a core clock component and as a blue light photoreceptor in Neurospora crassa. Loss of the amino-terminal polyglutamine (NpolyQ) domain in WC-1 results in an arrhythmic circadian clock; this data is consistent with this simple sequence repeat (SSR) being essential for clock function. Methodology/Principal Findings Since SSRs are often polymorphic in length across natural populations, we reasoned that investigating natural variation of the WC-1 NpolyQ may provide insight into its role in the circadian clock. We observed significant phenotypic variation in the period, phase and temperature compensation of circadian regulated asexual conidiation across 143 N. crassa accessions. In addition to the NpolyQ, we identified two other simple sequence repeats in WC-1. The sizes of all three WC-1 SSRs correlated with polymorphisms in other clock genes, latitude and circadian period length. Furthermore, in a cross between two N. crassa accessions, the WC-1 NpolyQ co-segregated with period length. Conclusions/Significance Natural variation of the WC-1 NpolyQ suggests a mechanism by which period length can be varied and selected for by the local environment that does not deleteriously affect WC-1 activity. Understanding natural variation in the N. crassa circadian clock will facilitate an understanding of how fungi exploit their environments. PMID:17726525

Body temperature variability (Part 2): masking influences of body temperature variability and a review of body temperature variability in disease.

PubMed

Kelly, Gregory S

2007-03-01

This is the second of a two-part review on body temperature variability. Part 1 discussed historical and modern findings on average body temperatures. It also discussed endogenous sources of temperature variability, including variations caused by site of measurement; circadian, menstrual, and annual biological rhythms; fitness; and aging. Part 2 reviews the effects of exogenous masking agents - external factors in the environment, diet, or lifestyle that can be a significant source of body temperature variability. Body temperature variability findings in disease states are also reviewed.

Arctic sea-ice variations from time-lapse passive microwave imagery

USGS Publications Warehouse

Campbell, W.J.; Ramseier, R.O.; Zwally, H.J.; Gloersen, P.

1980-01-01

This paper presents: (1) a short historical review of the passive microwave research on sea ice which established the observational and theoretical base permitting the interpretation of the first passive microwave images of Earth obtained by the Nimbus-5 ESMR; (2) the construction of a time-lapse motion picture film of a 16-month set of serial ESMR images to aid in the formidable data analysis task; and (3) a few of the most significant findings resulting from an early analysis of these data, using selected ESMR images to illustrate these findings. ?? 1980 D. Reidel Publishing Co.

Genetic variation in the myeloperoxidase gene and cognitive impairment in Multiple Sclerosis

PubMed Central

Manna, I; Valentino, P; La Russa, A; Condino, F; Nisticò, R; Liguori, M; Clodomiro, A; Andreoli, V; Pirritano, D; Cittadella, R; Quattrone, A

2006-01-01

There is evidence that multiple sclerosis (MS) may associated with cognitive impairment in 25 to 40% of cases. The gene encoding myeloperoxidase (MPO) is involved in molecular pathways leading to β-amyloid deposition. We investigated a functional biallelic (G/A) polymorphism in the promoter region (-463) of the MPO gene in 465 patients affected by MS, divided into 204 cognitively normal and 261 impaired. We did not find significant differences in allele or genotype distributions between impaired and preserved MS patients. Our findings suggest that MPO polymorphism is not a risk factor for cognitive impairment in MS. PMID:16504169

Genetic variation and gene expression across multiple tissues and developmental stages in a nonhuman primate.

PubMed

Jasinska, Anna J; Zelaya, Ivette; Service, Susan K; Peterson, Christine B; Cantor, Rita M; Choi, Oi-Wa; DeYoung, Joseph; Eskin, Eleazar; Fairbanks, Lynn A; Fears, Scott; Furterer, Allison E; Huang, Yu S; Ramensky, Vasily; Schmitt, Christopher A; Svardal, Hannes; Jorgensen, Matthew J; Kaplan, Jay R; Villar, Diego; Aken, Bronwen L; Flicek, Paul; Nag, Rishi; Wong, Emily S; Blangero, John; Dyer, Thomas D; Bogomolov, Marina; Benjamini, Yoav; Weinstock, George M; Dewar, Ken; Sabatti, Chiara; Wilson, Richard K; Jentsch, J David; Warren, Wesley; Coppola, Giovanni; Woods, Roger P; Freimer, Nelson B

2017-12-01

By analyzing multitissue gene expression and genome-wide genetic variation data in samples from a vervet monkey pedigree, we generated a transcriptome resource and produced the first catalog of expression quantitative trait loci (eQTLs) in a nonhuman primate model. This catalog contains more genome-wide significant eQTLs per sample than comparable human resources and identifies sex- and age-related expression patterns. Findings include a master regulatory locus that likely has a role in immune function and a locus regulating hippocampal long noncoding RNAs (lncRNAs), whose expression correlates with hippocampal volume. This resource will facilitate genetic investigation of quantitative traits, including brain and behavioral phenotypes relevant to neuropsychiatric disorders.

Evolution properties of online user preference diversity

NASA Astrophysics Data System (ADS)

Guo, Qiang; Ji, Lei; Liu, Jian-Guo; Han, Jingti

2017-02-01

Detecting the evolution properties of online user preference diversity is of significance for deeply understanding online collective behaviors. In this paper, we empirically explore the evolution patterns of online user rating preference, where the preference diversity is measured by the variation coefficient of the user rating sequence. The statistical results for four real systems show that, for movies and reviews, the user rating preference would become diverse and then get centralized finally. By introducing the empirical variation coefficient, we present a Markov model, which could regenerate the evolution properties of two online systems regarding to the stable variation coefficients. In addition, we investigate the evolution of the correlation between the user ratings and the object qualities, and find that the correlation would keep increasing as the user degree increases. This work could be helpful for understanding the anchoring bias and memory effects of the online user collective behaviors.

Variational Wavefunction for the Periodic Anderson Model with Onsite Correlation Factors

NASA Astrophysics Data System (ADS)

Kubo, Katsunori; Onishi, Hiroaki

2017-01-01

We propose a variational wavefunction containing parameters to tune the probabilities of all the possible onsite configurations for the periodic Anderson model. We call it the full onsite-correlation wavefunction (FOWF). This is a simple extension of the Gutzwiller wavefunction (GWF), in which one parameter is included to tune the double occupancy of the f electrons at the same site. We compare the energy of the GWF and the FOWF evaluated by the variational Monte Carlo method and that obtained with the density-matrix renormalization group method. We find that the energy is considerably improved in the FOWF. On the other hand, the physical quantities do not change significantly between these two wavefunctions as long as they describe the same phase, such as the paramagnetic phase. From these results, we not only demonstrate the improvement by the FOWF, but we also gain insights on the applicability and limitation of the GWF to the periodic Anderson model.

Long-term persistence of solar activity

NASA Technical Reports Server (NTRS)

Ruzmaikin, Alexander; Feynman, Joan; Robinson, Paul

1994-01-01

We examine the question of whether or not the non-periodic variations in solar activity are caused by a white-noise, random process. The Hurst exponent, which characterizes the persistence of a time series, is evaluated for the series of C-14 data for the time interval from about 6000 BC to 1950 AD. We find a constant Hurst exponent, suggesting that solar activity in the frequency range from 100 to 3000 years includes an important continuum component in addition to the well-known periodic variations. The value we calculate, H approximately 0.8, is significantly larger than the value of 0.5 that would correspond to variations produced by a white-noise process. This value is in good agreement with the results for the monthly sunspot data reported elsewhere, indicating that the physics that produces the continuum is a correlated random process and that it is the same type of process over a wide range of time interval lengths.

HIV-1 sequence variation between isolates from mother-infant transmission pairs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wike, C.M.; Daniels, M.R.; Furtado, M.

1991-12-31

To examine the sequence diversity of human immunodeficiency virus type 1 (HIV-1) between known transmission sets, sequences from the V3 and V4-V5 region of the env gene from 4 mother-infant pairs were analyzed. The mean interpatient sequence variation between isolates from linked mother-infant pairs was comparable to the sequence diversity found between isolates from other close contacts. The mean intrapatient variation was significantly less in the infants` isolates then the isolates from both their mothers and other characterized intrapatient sequence sets. In addition, a distinct and characteristic difference in the glycosylation pattern preceding the V3 loop was found between eachmore » linked transmission pair. These findings indicate that selection of specific genotypic variants, which may play a role in some direct transmission sets, and the duration of infection are important factors in the degree of diversity seen between the sequence sets.« less

Human leukocyte antigen and cytokine receptor gene polymorphisms associated with heterogeneous immune responses to mumps viral vaccine.

PubMed

Ovsyannikova, Inna G; Jacobson, Robert M; Dhiman, Neelam; Vierkant, Robert A; Pankratz, V Shane; Poland, Gregory A

2008-05-01

Mumps outbreaks continue to occur throughout the world, including in highly vaccinated populations. Vaccination against mumps has been successful; however, humoral and cellular immune responses to mumps vaccines vary significantly from person to person. We set out to assess whether HLA and cytokine gene polymorphisms are associated with variations in the immune response to mumps viral vaccine. To identify genetic factors that might contribute to variations in mumps vaccine-induced immune responses, we performed HLA genotyping in a group of 346 healthy schoolchildren (12-18 years of age) who previously received 2 doses of live mumps vaccine. Single-nucleotide polymorphisms (minor allele frequency of >5%) in cytokine and cytokine receptor genes were genotyped for a subset of 118 children. Median values for mumps-specific antibody titers and lymphoproliferative stimulation indices were 729 IU/mL and 4.8, respectively. Girls demonstrated significantly higher mumps antibody titers than boys, indicating gender-linked genetic differences in humoral immune response. Significant associations were found between the HLA-DQB1*0303 alleles and lower mumps-specific antibody titers. An interesting finding was the association of several HLA class II alleles with mumps-specific lymphoproliferation. Alleles of the DRB1 (*0101, *0301, *0801, *1001, *1201, and *1302), DQA1 (*0101, *0105, *0401, and *0501), and DQB1 (*0201, *0402, and *0501) loci were associated with significant variations in lymphoproliferative immune responses to mumps vaccine. Additional associations were observed with single-nucleotide polymorphisms in the interleukin-10RA, interleukin-12RB1, and interleukin-12RB2 cytokine receptor genes. Minor alleles for 4 single-nucleotide polymorphisms within interleukin-10RA and interleukin-12RB genes were associated with variations in humoral and cellular immune responses to mumps vaccination. These data suggest the important role of HLA and immunoregulatory cytokine receptor gene polymorphisms in explaining variations in mumps vaccine-induced immune responses.

Human Leukocyte Antigen and Cytokine Receptor Gene Polymorphisms Associated With Heterogeneous Immune Responses to Mumps Viral Vaccine

PubMed Central

Ovsyannikova, Inna G.; Jacobson, Robert M.; Dhiman, Neelam; Vierkant, Robert A.; Pankratz, V. Shane; Poland, Gregory A.

2009-01-01

OBJECTIVES Mumps outbreaks continue to occur throughout the world, including in highly vaccinated populations. Vaccination against mumps has been successful; however, humoral and cellular immune responses to mumps vaccines vary significantly from person to person. We set out to assess whether HLA and cytokine gene polymorphisms are associated with variations in the immune response to mumps viral vaccine. METHODS To identify genetic factors that might contribute to variations in mumps vaccine–induced immune responses, we performed HLA genotyping in a group of 346 healthy schoolchildren (12–18 years of age) who previously received 2 doses of live mumps vaccine. Single-nucleotide polymorphisms (minor allele frequency of >5%) in cytokine and cytokine receptor genes were genotyped for a subset of 118 children. RESULTS Median values for mumps-specific antibody titers and lymphoproliferative stimulation indices were 729 IU/mL and 4.8, respectively. Girls demonstrated significantly higher mumps antibody titers than boys, indicating gender-linked genetic differences in humoral immune response. Significant associations were found between the HLA-DQB1*0303 alleles and lower mumps-specific antibody titers. An interesting finding was the association of several HLA class II alleles with mumps-specific lymphoproliferation. Alleles of the DRB1 (*0101, *0301, *0801, *1001, *1201, and *1302), DQA1 (*0101, *0105, *0401, and *0501), and DQB1 (*0201, *0402, and *0501) loci were associated with significant variations in lymphoproliferative immune responses to mumps vaccine. Additional associations were observed with single-nucleotide polymorphisms in the interleukin-10RA, interleukin-12RB1, and interleukin-12RB2 cytokine receptor genes. Minor alleles for 4 single-nucleotide polymorphisms within interleukin-10RA and interleukin-12RB genes were associated with variations in humoral and cellular immune responses to mumps vaccination. CONCLUSIONS These data suggest the important role of HLA and immunoregulatory cytokine receptor gene polymorphisms in explaining variations in mumps vaccine–induced immune responses. PMID:18450852

Variation in the gonadotrophin-releasing hormone-1 and the song control system in the tropical breeding rufous-collared sparrow (Zonotrichia capensis) is dependent on sex and reproductive state.

PubMed

Stevenson, Tyler J; Small, Thomas W; Ball, Gregory F; Moore, Ignacio T

2012-08-01

Seasonal breeding in temperate zone vertebrates is characterised by pronounced variation in both central and peripheral reproductive physiology as well as behaviour. In contrast, many tropical species have a comparatively longer and less of a seasonal pattern of breeding than their temperate zone counterparts. These extended, more "flexible" reproductive periods may be associate with a lesser degree of annual variation in reproductive physiology. Here we investigated variation in the neuroendocrine control of reproduction in relation to the changes in the neural song control system in a tropical breeding songbird the rufous-collared sparrows (Zonotrichia capensis). Using in situ hybridization, we show that the optical density of GnRH1 mRNA expression is relatively constant across pre-breeding and breeding states. However, males were found to have significantly greater expression compared to females regardless of breeding state. Both males and females showed marked variation in measures of peripheral reproductive physiology with greater gonadal volumes and concentrations of sex steroids in the blood (i.e. testosterone in males; estrogen in females) during the breeding season as compared to the pre-breeding season. These findings suggest that the environmental cues regulating breeding in a tropical breeding bird ultimately exert their effects on physiology at the level of the median eminence and regulate the release of GnRH1. In addition, histological analysis of the song control system HVC, RA and Area X revealed that breeding males had significantly larger volumes of these brain nuclei as compared to non-breeding males, breeding females, and non-breeding females. Females did not exhibit a significant difference in the size of song control regions across breeding states. Together, these data show a marked sex difference in the extent to which there is breeding-associated variation in reproductive physiology and brain plasticity that is dependent on the reproductive state in a tropical breeding songbird. Copyright © 2012 Elsevier Inc. All rights reserved.

Hypothesis: discrepancy between intra- and interpopulation studies of the relationship between dietary salt and blood pressure: fact or fiction?

PubMed

Omvik, P

1984-01-01

It is a paradox that intra-population studies fail to show significant correlation between sodium excretion and blood pressure while a clear relationship exists in cross-cultural studies. Since daily variation of sodium excretion is high, the discrepancy between the two observations could be due to non-comparable data on sodium excretion. This is a discussion of the hypothesis that the finding of a significant correlation or not between sodium excretion and blood pressure depends on the statistical analysis of the data.

DIVERGENT HORIZONTAL SUB-SURFACE FLOWS WITHIN ACTIVE REGION 11158

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jain, Kiran; Tripathy, S. C.; Hill, F., E-mail: kjain@nso.edu, E-mail: stripathy@nso.edu, E-mail: fhill@nso.edu

We measure the horizontal subsurface flow in a fast emerging active region (AR; NOAA 11158) using the ring-diagram technique and the Helioseismic and Magnetic Imager high spatial resolution Dopplergrams. This AR had a complex magnetic structure and displayed significant changes in morphology during its disk passage. Over a period of six days from 2011 February 11 to 16, the temporal variation in the magnitude of the total velocity is found to follow the trend of magnetic field strength. We further analyze regions of individual magnetic polarity within AR 11158 and find that the horizontal velocity components in these sub-regions havemore » significant variation with time and depth. The leading and trailing polarity regions move faster than the mixed-polarity region. Furthermore, both zonal and meridional components have opposite signs for trailing and leading polarity regions at all depths showing divergent flows within the AR. We also find a sharp decrease in the magnitude of total horizontal velocity in deeper layers around major flares. It is suggested that the re-organization of magnetic fields during flares, combined with the sunspot rotation, decreases the magnitude of horizontal flows or that the flow kinetic energy has been converted into the energy released by flares. After the decline in flare activity and sunspot rotation, the flows tend to follow the pattern of magnetic activity. We also observe less variation in the velocity components near the surface but these tend to increase with depth, further demonstrating that the deeper layers are more affected by the topology of ARs.« less

Healthcare system and the wealth-health gradient: a comparative study of older populations in six countries.

PubMed

Maskileyson, Dina

2014-10-01

The present study provides a comparative analysis of the association between wealth and health in six healthcare systems (Sweden, the United Kingdom, Germany, the Czech Republic, Israel, the United States). National samples of individuals fifty years and over reveal considerable cross-country variations in health outcomes. In all six countries wealth and health are positively associated. The findings also show that state-based healthcare systems produce better population health outcomes than private-based healthcare systems. The results indicate that in five out of the six countries studied, the wealth-health gradients were remarkably similar, despite significant variations in healthcare system type. Only in the United States was the association between wealth and health substantially different from, and much greater than that in the other five countries. The findings suggest that private-based healthcare system in the U.S. is likely to promote stronger positive associations between wealth and health. Copyright © 2014 Elsevier Ltd. All rights reserved.

Leap motion evaluation for assessment of upper limb motor skills in Parkinson's disease.

PubMed

Butt, A H; Rovini, E; Dolciotti, C; Bongioanni, P; De Petris, G; Cavallo, F

2017-07-01

The main goal of this study is to investigate the potential of the Leap Motion Controller (LMC) for the objective assessment of motor dysfunctioning in patients with Parkinson's disease (PwPD). The most relevant clinical signs in Parkinson's Disease (PD), such as slowness of movements, frequency variation, amplitude variation, and speed, were extracted from the recorded LMC data. Data were clinically quantified using the LMC software development kit (SDK). In this study, 16 PwPD subjects and 12 control healthy subjects were involved. A neurologist assessed the subjects during the task execution, assigning them a score according to the MDS/UPDRS-Section III items. Features of motor performance from both subject groups (patients and healthy controls) were extracted with dedicated algorithms. Furthermore, to find out the significance of such features from the clinical point of view, machine learning based methods were used. Overall, our findings showed the moderate potential of LMC to extract the motor performance of PwPD.

Parallelism and Epistasis in Skeletal Evolution Identified through Use of Phylogenomic Mapping Strategies

PubMed Central

Daane, Jacob M.; Rohner, Nicolas; Konstantinidis, Peter; Djuranovic, Sergej; Harris, Matthew P.

2016-01-01

The identification of genetic mechanisms underlying evolutionary change is critical to our understanding of natural diversity, but is presently limited by the lack of genetic and genomic resources for most species. Here, we present a new comparative genomic approach that can be applied to a broad taxonomic sampling of nonmodel species to investigate the genetic basis of evolutionary change. Using our analysis pipeline, we show that duplication and divergence of fgfr1a is correlated with the reduction of scales within fishes of the genus Phoxinellus. As a parallel genetic mechanism is observed in scale-reduction within independent lineages of cypriniforms, our finding exposes significant developmental constraint guiding morphological evolution. In addition, we identified fixed variation in fgf20a within Phoxinellus and demonstrated that combinatorial loss-of-function of fgfr1a and fgf20a within zebrafish phenocopies the evolved scalation pattern. Together, these findings reveal epistatic interactions between fgfr1a and fgf20a as a developmental mechanism regulating skeletal variation among fishes. PMID:26452532

Computed tomographic morphometry of tympanic bulla shape and position in brachycephalic and mesaticephalic dog breeds.

PubMed

Mielke, Ben; Lam, Richard; Ter Haar, Gert

2017-09-01

Anatomic variations in skull morphology have been previously described for brachycephalic dogs; however there is little published information on interbreed variations in tympanic bulla morphology. This retrospective observational study aimed to (1) provide detailed descriptions of the computed tomographic (CT) morphology of tympanic bullae in a sample of dogs representing four brachycephalic breeds (Pugs, French Bulldogs, English Bulldog, and Cavalier King Charles Spaniels) versus two mesaticephalic breeds (Labrador retrievers and Jack Russell Terriers); and (2) test associations between tympanic bulla morphology and presence of middle ear effusion. Archived head CT scans for the above dog breeds were retrieved and a single observer measured tympanic bulla shape (width:height ratio), wall thickness, position relative to the temporomandibular joint, and relative volume (volume:body weight ratio). A total of 127 dogs were sampled. Cavalier King Charles Spaniels had significantly flatter tympanic bullae (greater width:height ratios) versus Pugs, English Bulldogs, Labrador retrievers, and Jack Russell terriers. French Bulldogs and Pugs had significantly more overlap between tympanic bullae and temporomandibular joints versus other breeds. All brachycephalic breeds had significantly lower tympanic bulla volume:weight ratios versus Labrador retrievers. Soft tissue attenuating material (middle ear effusion) was present in the middle ear of 48/100 (48%) of brachycephalic breeds, but no significant association was found between tympanic bulla CT measurements and presence of this material. Findings indicated that there are significant interbreed variations in tympanic bulla morphology, however no significant relationship between tympanic bulla morphology and presence of middle ear effusion could be identified. © 2017 American College of Veterinary Radiology.

Differential sensitivity of polyhydroxyalkanoate producing bacteria to fermentation inhibitors and comparison of polyhydroxybutyrate production from Burkholderia cepacia and Pseudomonas pseudoflava

PubMed Central

2013-01-01

Background The aim of this study is determine the relative sensitivity of a panel of seven polyhydroxyalkanoate producing bacteria to a panel of seven lignocellulosic-derived fermentation inhibitors representing aliphatic acids, furans and phenolics. A further aim was to measure the polyhydroxybutyrate production of select organisms on lignocellulosic-derived monosaccharides arabinose, xylose, glucose and mannose. Findings We examined the sensitivity of seven polyhydroxyalkanoate producing bacteria: Azohydromonas lata, Bacillus megaterium, Bacillus cereus, Burkholderia cepacia, Pseudomonas olevorans, Pseudomonas pseudoflava and Ralstonia eutropha, against seven fermentation inhibitors produced by the saccharification of lignocellulose: acetic acid, levulinic acid, coumaric acid, ferulic acid, syringaldehyde, furfural, and hyroxymethyfurfural. There was significant variation in the sensitivity of these microbes to representative phenolics ranging from 0.25-1.5 g/L coumaric and ferulic acid and between 0.5-6.0 g/L syringaldehyde. Inhibition ranged from 0.37-4 g/L and 0.75-6 g/L with acetic acid and levulinic acid, respectively. B. cepacia and P. pseudoflava were selected for further analysis of polyhydroxyalkanoate production. Conclusions We find significant differences in sensitivity to the fermentation inhibitors tested and find these variations to be over a relevant concentration range given the concentrations of inhibitors typically found in lignocellulosic hydrolysates. Of the seven bacteria tested, B. cepacia demonstrated the greatest inhibitor tolerance. Similarly, of two organisms examined for polyhydroxybutyrate production, B. cepacia was notably more efficient when fermenting pentose substrates. PMID:23734728

Individual Differences in Dynamic Functional Brain Connectivity across the Human Lifespan

PubMed Central

Davison, Elizabeth N.; Turner, Benjamin O.; Miller, Michael B.; Carlson, Jean M.

2016-01-01

Individual differences in brain functional networks may be related to complex personal identifiers, including health, age, and ability. Dynamic network theory has been used to identify properties of dynamic brain function from fMRI data, but the majority of analyses and findings remain at the level of the group. Here, we apply hypergraph analysis, a method from dynamic network theory, to quantify individual differences in brain functional dynamics. Using a summary metric derived from the hypergraph formalism—hypergraph cardinality—we investigate individual variations in two separate, complementary data sets. The first data set (“multi-task”) consists of 77 individuals engaging in four consecutive cognitive tasks. We observe that hypergraph cardinality exhibits variation across individuals while remaining consistent within individuals between tasks; moreover, the analysis of one of the memory tasks revealed a marginally significant correspondence between hypergraph cardinality and age. This finding motivated a similar analysis of the second data set (“age-memory”), in which 95 individuals, aged 18–75, performed a memory task with a similar structure to the multi-task memory task. With the increased age range in the age-memory data set, the correlation between hypergraph cardinality and age correspondence becomes significant. We discuss these results in the context of the well-known finding linking age with network structure, and suggest that hypergraph analysis should serve as a useful tool in furthering our understanding of the dynamic network structure of the brain. PMID:27880785

Finding a Needle in a Climate Haystack

NASA Astrophysics Data System (ADS)

Verosub, K. L.; Medrano, R.; Valentine, M.

2014-12-01

We are studying the regional impact of volcanic eruptions that might have caused global cooling using high-quality annual-resolution proxy records of natural phenomena, such as tree-ring widths, and cultural events, such as the dates of the beginning of grape and rye harvests. To do this we need to determine if the year following an eruption was significantly colder and wetter than preceding or subsequent years as measured by any given proxy and if that year is consistently cold and wet across different proxies. The problem is complicated by the fact that normal inter-annual variations in any given proxy can be quite large and can obscure any volcanological impact and by the fact that inter-annual variations for different proxies will have different means and standard deviations. We address the first problem by assuming that on a regional scale, the inter-annual variations of different proxies are at best only weakly correlated and that, in the absence of a volcanological signal, these variations will average out on a regional scale. We address the second problem by renormalizing each record so that it has the same mean and standard deviation over a given time interval. We then sum the re-normalized records on a year-by-year basis and look for years with significantly higher total scores. The method can also be used to assess the statistical significance of an anomalous value. Our initial analysis of records primarily from the Northern Hemisphere shows that the years 1601 and 1816 were significantly colder and wetter than any others in the past 500 years. These years followed the eruptions of Huayanaputina in Chile and Tambora in Indonesia, respectively, by one year. The years 1698 and 1837 also show up as being climatologically severe although they have not (yet) been associated with specific volcanic eruptions.

Vocal mechanics in Darwin's finches: correlation of beak gape and song frequency.

PubMed

Podos, Jeffrey; Southall, Joel A; Rossi-Santos, Marcos R

2004-02-01

Recent studies of vocal mechanics in songbirds have identified a functional role for the beak in sound production. The vocal tract (trachea and beak) filters harmonic overtones from sounds produced by the syrinx, and birds can fine-tune vocal tract resonance properties through changes in beak gape. In this study, we examine patterns of beak gape during song production in seven species of Darwin's finches of the Galápagos Islands. Our principal goals were to characterize the relationship between beak gape and vocal frequency during song production and to explore the possible influence therein of diversity in beak morphology and body size. Birds were audio and video recorded (at 30 frames s(-1)) as they sang in the field, and 164 song sequences were analyzed. We found that song frequency regressed significantly and positively on beak gape for 38 of 56 individuals and for all seven species examined. This finding provides broad support for a resonance model of vocal tract function in Darwin's finches. Comparison among species revealed significant variation in regression y-intercept values. Body size correlated negatively with y-intercept values, although not at a statistically significant level. We failed to detect variation in regression slopes among finch species, although the regression slopes of Darwin's finch and two North American sparrow species were found to differ. Analysis within one species (Geospiza fortis) revealed significant inter-individual variation in regression parameters; these parameters did not correlate with song frequency features or plumage scores. Our results suggest that patterns of beak use during song production were conserved during the Darwin's finch adaptive radiation, despite the evolution of substantial variation in beak morphology and body size.

Two unusual anatomic variations create a diagnostic dilemma in distal ulnar nerve compression.

PubMed

Kiehn, Mark W; Derrick, Allison J; Iskandar, Bermans J

2008-09-01

Diagnosis of peripheral neuropathies is based upon patterns of functional deficits and electrodiagnostic testing. However, anatomic variations can lead to confounding patterns of physical and electrodiagnostic findings. Authors present a case of ulnar nerve compression due to a rare combination of anatomic variations, aberrant branching pattern, and FCU insertion at the wrist, which posed a diagnostic and therapeutic dilemma. The literature related to isolated distal ulnar motor neuropathy and anatomic variations of the ulnar nerve and adjacent structures is also reviewed. This case demonstrates how anatomic variations can complicate the interpretation of clinical and electrodiagnostic findings and underscores the importance of thorough exploration of the nerve in consideration for possible variations. (c) 2008 Wiley-Liss, Inc.

Lower Lateral Cartilage Cephalic Malposition: An Over-Diagnosed Entity.

PubMed

Hafezi, Farhad; Naghibzadeh, Bijan; Kazemi Ashtiani, Abbas

2018-06-01

Lower lateral cartilage malposition is represented by anterior convexity of the lower lateral cartilage (LLC) dome with posterior pinch, as defined by Sheen and Constantian. This anatomic variation consists of cephalic, or upward and inward, rotation of lateral crura, particularly in bulbous tip patients. In most cases, "bulbous pinch" LLC is positioned toward the medial canthus, not laterally, so it is referred to as cephalic displacement. Accordingly, it is recommended to caudally displace cartilage in the majority of rhinoplasty cases in which variation is seen. The purpose of this paper is to measure the exact angle of lateral crura with fixed reference points on the face. We drew and marked LLC contours and vertical/horizontal lines in 40 consecutive rhinoplasty cases. We then divided them into two groups: (1) bulbous pinch and (2) flat LLCs. The right- and left-sided LLC angles to midline and horizontal lines were measured and compared to assess whether there was any significant difference between the two subgroups. There was no significant difference between the angles of LLC rotation in the bulbous and flat LLCs groups, measured both vertically and horizontally. Based on our findings, although cephalic malposition of LLCs may be present in some patients but in the majority of cases the etiology of nasal lateral wall pinching is not cephalic displacement of lateral crura but most probably is due, rather, to severe convexity of the posterior and lateral crura. According to our findings, cephalic malposition is an uncommon anatomic variation of LLCs that has been reported at high frequency (60-70% of their rhinoplasty cases). This finding may help to correct this deformity into a normal anatomic configuration. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A reanalysis of the SWP-HI IUE observations of Capella

NASA Technical Reports Server (NTRS)

Wood, Brian E.; Ayres, T. R.

1995-01-01

We have reanalyzed the numerous high-resolution, far-ultraviolet observations of Capella made by the International Ultraviolet Explorer (IUE) in its 16 yr lifetime. Our purpose was to search for long-term profile variations in Capella's ultraviolet emission lines and to complement the analysis of Goddard High Resolution Spectrograph (GHRS) observations of Capella, discussed in a companion paper (Linsky et al. 1995). We implemented a state-of-the-art photometric correction and spectral extraction procedure to improve S/N and control potential sources for systematic errors. Nevertheless, we were unable to find compelling evidence for any significant long-term profile variations. Previous work has shown that the G8 primary star is only a minor contributor to the high-excitation transition region lines but is a significant contributor to the low-excitation chromospheric lines. We have found exceptions to this rule, however. We find that the G8 star is responsible for a significant portion of Capella's N V lambda lambda 1239, 1243 emission, but is not a large contributor to the S I lambda 1296, Cl I lambda 1352, and O lambda 1356 lines. We suggest possible explanations for these behaviors. We also find evidence that the He II lambda 1640 emission from the G1 star is from the transition region, while the He II lambda 1640 emission from the G8 star is chromospheric, consistent with the findings of Linsky et al. (1994). The C II lambda 1336 line shows a weak central reversal. It is blueshifted by about 9 km/s with respect to the centroid of the emission from the G1 star. While the central reversal of the C II line is blueshifted by about 9 km/s with respect to the centroid of the emission from the G1 star. While the central reversal of the C II line is blueshifted, the central reversal of the Si III lambda 1207 line discussed by Linsky et al. (1994) is not.

Spectral models for early time SN 2011fe observations

NASA Astrophysics Data System (ADS)

Baron, E.; Hoeflich, P.; Friesen, Brian; Sullivan, M.; Hsiao, E.; Ellis, R. S.; Gal-Yam, A.; Howell, D. A.; Nugent, P. E.; Dominguez, I.; Krisciunas, K.; Phillips, M. M.; Suntzeff, N.; Wang, L.; Thomas, R. C.

2015-12-01

We use observed UV through near-IR spectra to examine whether SN 2011fe can be understood in the framework of Branch-normal Type Ia supernovae (SNe Ia) and to examine its individual peculiarities. As a benchmark, we use a delayed-detonation model with a progenitor metallicity of Z⊙/20. We study the sensitivity of features to variations in progenitor metallicity, the outer density profile, and the distribution of radioactive nickel. The effect of metallicity variations in the progenitor have a relatively small effect on the synthetic spectra. We also find that the abundance stratification of SN 2011fe resembles closely that of a delayed-detonation model with a transition density that has been fit to other Branch-normal SNe Ia. At early times, the model photosphere is formed in material with velocities that are too high, indicating that the photosphere recedes too slowly or that SN 2011fe has a lower specific energy in the outer ≈0.1 M⊙ than does the model. We discuss several explanations for the discrepancies. Finally, we examine variations in both the spectral energy distribution and in the colours due to variations in the progenitor metallicity, which suggests that colours are only weak indicators for the progenitor metallicity, in the particular explosion model that we have studied. We do find that the flux in the U band is significantly higher at maximum light in the solar metallicity model than in the lower metallicity model and the lower metallicity model much better matches the observed spectrum.

Relative Effects of Juvenile and Adult Environmental Factors on Mate Attraction and Recognition in the Cricket, Allonemobius socius

PubMed Central

Olvido, Alexander E.; Fernandes, Pearl R.; Mousseau, Timothy A.

2010-01-01

Finding a mate is a fundamental aspect of sexual reproduction. To this end, specific-mate recognition systems (SMRS) have evolved that facilitate copulation between producers of the mating signal and their opposite-sex responders. Environmental variation, however, may compromise the efficiency with which SMRS operate. In this study, the degree to which seasonal climate experienced during juvenile and adult life-cycle stages affects the SMRS of a cricket, Allonemobius socius (Scudder) (Orthoptera: Gryllidae) was assessed. Results from two-choice behavioral trials suggest that adult ambient temperature, along with population and family origins, mediate variation in male mating call, and to a lesser extent directional response of females for those calls. Restricted maximum-likelihood estimates of heritability for male mating call components and for female response to mating call appeared statistically nonsignificant. However, appreciable “maternal genetic effects” suggest that maternal egg provisioning and other indirect maternal determinants of the embryonic environment significantly contributed to variation in male mating call and female response to mating calls. Thus, environmental factors can generate substantial variation in A. socius mating call, and, more importantly, their marginal effect on female responses to either fast-chirp or long-chirp mating calls suggest negative fitness consequences to males producing alternative types of calls. Future studies of sexual selection and SMRS evolution, particularly those focused on hybrid zone dynamics, should take explicit account of the loose concordance between signal producers and responders suggested by the current findings. PMID:20673114

Low maternal melatonin level increases autism spectrum disorder risk in children.

PubMed

Braam, Wiebe; Ehrhart, Friederike; Maas, Anneke P H M; Smits, Marcel G; Curfs, Leopold

2018-02-28

It is assumed that autism spectrum disorder (ASD) is caused by a combination of de novo inherited variation and common variation as well as environmental factors. It often co-occurs with intellectual disability (ID). Almost eight hundred potential causative genetic variations have been found in ASD patients. However, not one of them is responsible for more than 1% of ASD cases. Low melatonin levels are a frequent finding in ASD patients. Melatonin levels are negatively correlated with severity of autistic impairments, it is important for normal neurodevelopment and is highly effective in protecting DNA from oxidative damage. Melatonin deficiency could be a major factor, and well a common heritable variation, that increases the susceptibility to environmental risk factors for ASD. ASD is already present at birth. As the fetus does not produce melatonin, low maternal melatonin levels may be involved. We measured 6-sulfatoxymelatonin in urine of 60 mothers of a child with ASD and controls. 6-sulfatoxymelatonin levels were significantly lower in mothers with an ASD child than in controls (p = 0.012). Low parental melatonin levels could be one of the contributors to ASD and possibly ID etiology. Our findings need to be duplicated on a larger scale. If our hypothesis is correct, this could lead to policies to detect future parents who are at risk and to treatment strategies to ASD and intellectual disability risk. Copyright © 2018 Elsevier Ltd. All rights reserved.

Possible solution to the riddle of HD 82943 multiplanet system: the three-planet resonance 1:2:5?

NASA Astrophysics Data System (ADS)

Baluev, Roman V.; Beaugé, Cristian

2014-03-01

We carry out a new analysis of the published radial velocity data for the planet-hosting star HD 82943. We include the recent Keck/HIRES measurements as well as the aged but much more numerous CORALIE data. We find that the CORALIE radial velocity measurements are polluted by a systematic annual variation which affected the robustness of many previous results. We show that after purging this variation, the residuals still contain a clear signature of an additional ˜1100 d periodicity. The latter variation leaves significant hints in all three independent radial velocity subsets that we analysed: the CORALIE data, the Keck data acquired prior to a hardware upgrade and the Keck data taken after the upgrade. We mainly treat this variation as a signature of a third planet in the system, although we cannot rule out other interpretations, such as long-term stellar activity. We find it easy to naturally obtain a stable three-planet radial velocity fit close to the three-planet mean-motion resonance 1:2:5, with the two main planets (those in the 1:2 resonance) in an aligned apsidal corotation. The dynamical status of the third planet is still uncertain: it may reside in as well as slightly out of the 5:2 resonance. We obtain the value of about 1075 d for its orbital period and ˜0.3MJup for its minimum mass, while the eccentric parameters are uncertain.

A small variation in diet influences the Lactobacillus strain composition in the crop of broiler chickens.

PubMed

Hammons, Susan; Oh, Phaik Lyn; Martínez, Inés; Clark, Kenzi; Schlegel, Vicki L; Sitorius, Emily; Scheideler, Sheila E; Walter, Jens

2010-08-01

Feed composition has the potential to influence the activities of bacteria that colonize the digestive tract of broiler chickens with important consequences for animal health, well being, and food safety. In this study, the gut microbiota of two groups of broiler chickens raised in immediate vicinity but fed either a standard corn/soybean meal ration (corn-soy, CS) or a ration high in wheat middlings (high wheat, HW) was characterized. The findings revealed that this small variation in feed composition did not influence the distribution of microbial species present in the microbial community throughout the digestive tract. However, diet variation markedly influenced the Lactobacillus strain composition in the crop. Most striking, the dominant type in birds on the CS diet (Lactobacillus agilis type R5), which comprised 25% of the isolates, was not detected in birds fed the HW diet. The latter birds harbored a different strain of L. agilis (type R1) in a significantly higher ratio than birds on the CS diet. Several other strains were also specific to the particular diet. In conclusion, this study showed that a small variation in the composition of chicken feed that does not result in detectable differences in species composition can still have an impact on which microbial strains become dominant in the digestive tract. This finding has relevance in the application of probiotics and other direct-fed microbials in poultry husbandry. Copyright 2010 Elsevier GmbH. All rights reserved.

Patterns of variation in clutch sizes in a guild of temperate-nesting dabbling ducks

USGS Publications Warehouse

Krapu, G.L.; Reynolds, R.E.; Sargeant, G.A.; Renner, R.W.

2004-01-01

Clutch sizes of temperate-nesting dabbling ducks vary widely within and between years. Biologists have long been interested in why such patterns exist but have had difficulty separating intrinsic effects from environmental influences. In an attempt to gain greater insight into the roles of intrinsic and environmental influences on clutch sizes of dabbling ducks, we compared clutch-size patterns of mallard, northern pintail, gadwall, northern shoveler, and blue-winged teal in North Dakota and South Dakota over a 3-year period. The study was conducted during 1993-1995 when wetland habitat conditions were exceptionally consistent within time intervals but varied widely from the onset to the end of the study. We found that clutch sizes of gadwall and blue-winged teal were significantly smaller at the onset of nesting in 1993, when water conditions remained relatively poor following a 5-year drought (1988-1992), and pintail clutch sizes were larger late in the breeding season in 1993 after wetland conditions became exceptionally productive following heavy rains in late May and June. These findings were associated with gadwall and teal relying primarily on nutrients acquired on the breeding grounds to produce early clutches, and pintails using an exceptionally high proportion of their body lipids to produce early clutches, making this species highly dependent on abundant local sources of lipids for clutches produced later. Mallard, pintail, and shoveler rely largely on endogenous lipids carried to the breeding grounds to produce early clutches, and at least in the years of study, clutch sizes exhibited minimal variation at the onset of nesting. Our findings, when examined in context with existing information, suggest that interspecific variation in clutch sizes results from innate differences in several traits -- including body size, diet, timing of lipid acquisition, and nesting-- that affect the amount of lipid available for egg production. Annual differences in clutch sizes of all five species were not significant when effects of annual variation in nest initiation dates was accounted for, reflecting the key role of environmental influences on intraspecific variation among years.

Aggregation of population‐based genetic variation over protein domain homologues and its potential use in genetic diagnostics

PubMed Central

Wiel, Laurens; Venselaar, Hanka; Veltman, Joris A.; Vriend, Gert

2017-01-01

Abstract Whole exomes of patients with a genetic disorder are nowadays routinely sequenced but interpretation of the identified genetic variants remains a major challenge. The increased availability of population‐based human genetic variation has given rise to measures of genetic tolerance that have been used, for example, to predict disease‐causing genes in neurodevelopmental disorders. Here, we investigated whether combining variant information from homologous protein domains can improve variant interpretation. For this purpose, we developed a framework that maps population variation and known pathogenic mutations onto 2,750 “meta‐domains.” These meta‐domains consist of 30,853 homologous Pfam protein domain instances that cover 36% of all human protein coding sequences. We find that genetic tolerance is consistent across protein domain homologues, and that patterns of genetic tolerance faithfully mimic patterns of evolutionary conservation. Furthermore, for a significant fraction (68%) of the meta‐domains high‐frequency population variation re‐occurs at the same positions across domain homologues more often than expected. In addition, we observe that the presence of pathogenic missense variants at an aligned homologous domain position is often paired with the absence of population variation and vice versa. The use of these meta‐domains can improve the interpretation of genetic variation. PMID:28815929

Blazhko modulation in the infrared

NASA Astrophysics Data System (ADS)

Jurcsik, J.; Hajdu, G.; Dékány, I.; Nuspl, J.; Catelan, M.; Grebel, E. K.

2018-04-01

We present first direct evidence of modulation in the K band of Blazhko-type RR Lyrae stars that are identified by their secular modulations in the I-band data of Optical Gravitational Lensing Experiment-IV. A method has been developed to decompose the K-band light variation into two parts originating from the temperature and the radius changes using synthetic data of atmosphere-model grids. The amplitudes of the temperature and the radius variations derived from the method for non-Blazhko RRab stars are in very good agreement with the results of the Baade-Wesselink analysis of RRab stars in the M3 globular cluster confirming the applicability and correctness of the method. It has been found that the Blazhko modulation is primarily driven by the change in the temperature variation. The radius variation plays a marginal part, moreover it has an opposite sign as if the Blazhko effect was caused by the radii variations. This result reinforces the previous finding based on the Baade-Wesselink analysis of M3 (NGC 5272) RR Lyrae, that significant modulation of the radius variations can only be detected in radial-velocity measurements, which relies on spectral lines that form in the uppermost atmospheric layers. Our result gives the first insight into the energetics and dynamics of the Blazhko phenomenon, hence it puts strong constraints on its possible physical explanations.

Association of parameter, software, and hardware variation with large-scale behavior across 57,000 climate models

PubMed Central

Knight, Christopher G.; Knight, Sylvia H. E.; Massey, Neil; Aina, Tolu; Christensen, Carl; Frame, Dave J.; Kettleborough, Jamie A.; Martin, Andrew; Pascoe, Stephen; Sanderson, Ben; Stainforth, David A.; Allen, Myles R.

2007-01-01

In complex spatial models, as used to predict the climate response to greenhouse gas emissions, parameter variation within plausible bounds has major effects on model behavior of interest. Here, we present an unprecedentedly large ensemble of >57,000 climate model runs in which 10 parameters, initial conditions, hardware, and software used to run the model all have been varied. We relate information about the model runs to large-scale model behavior (equilibrium sensitivity of global mean temperature to a doubling of carbon dioxide). We demonstrate that effects of parameter, hardware, and software variation are detectable, complex, and interacting. However, we find most of the effects of parameter variation are caused by a small subset of parameters. Notably, the entrainment coefficient in clouds is associated with 30% of the variation seen in climate sensitivity, although both low and high values can give high climate sensitivity. We demonstrate that the effect of hardware and software is small relative to the effect of parameter variation and, over the wide range of systems tested, may be treated as equivalent to that caused by changes in initial conditions. We discuss the significance of these results in relation to the design and interpretation of climate modeling experiments and large-scale modeling more generally. PMID:17640921

Within-species patterns challenge our understanding of the causes and consequences of trait variation with implications for trait-based models

NASA Astrophysics Data System (ADS)

Anderegg, L. D.; Berner, L. T.; Badgley, G.; Hillerislambers, J.; Law, B. E.

2017-12-01

Functional traits could facilitate ecological prediction by provide scale-free tools for modeling ecosystem function. Yet much of their utility lies in three key assumptions: 1) that global patterns of trait covariation are the result of universal trade-offs independent of taxonomic scale, so empirical trait-trait relationships can be used to constrain vegetation models 2) that traits respond predictably to environmental gradients and can therefore be reliably quantified to parameterize models and 3) that well sampled traits influence productivity. We use an extensive dataset of within-species leaf trait variation in North American conifers combined with global leaf trait datasets to test these assumptions. We examine traits central to the `leaf economics spectrum', and quantify patterns of trait variation at multiple taxonomic scales. We also test whether site environment explains geographic trait variation within conifers, and ask whether foliar traits explain geographic variation in relative growth rates. We find that most leaf traits vary primarily between rather than within species globally, but that a large fraction of within-PFT trait variation is within-species. We also find that some leaf economics spectrum relationships differ in sign within versus between species, particularly the relationship between leaf lifespan and LMA. In conifers, we find weak and inconsistent relationships between site environment and leaf traits, making it difficult capture within-species leaf trait variation for regional model parameterization. Finally, we find limited relationships between tree relative growth rate and any foliar trait other than leaf lifespan, with leaf traits jointly explaining 42% of within-species growth variation but environmental factors explaining 77% of variation. We suggest that additional traits, particularly whole plant allometry/allocation traits may be better than leaf traits for improving vegetation model performance at smaller taxonomic and spatial scales.

Multidecadal changes in winter circulation-climate relationship in Europe: frequency variations, within-type modifications, and long-term trends

NASA Astrophysics Data System (ADS)

Küttel, Marcel; Luterbacher, Jürg; Wanner, Heinz

2011-03-01

Using pressure fields classified by the SANDRA algorithm, this study investigates the changes in the relationship between North Atlantic/European sea level pressure (SLP) and gridded European winter (DJF) temperature and precipitation back to 1750. Important changes in the frequency of the SLP clusters are found, though none of them indicating significant long-term trends. However, for the majority of the SLP clusters a tendency toward overall warmer and partly wetter winter conditions is found, most pronounced over the last decades. This suggests important within-type variations, i.e. the temperature and precipitation fields related to a particular SLP pattern change their characteristics over time. Using a decomposition scheme we find for temperature and precipitation that within-type-related variations dominate over those due to changed frequencies of the SLP clusters: Approximately 70% (60%) of European winter temperature (precipitation) variations can be explained by within-type changes, most strongly expressed over Eastern Europe and Scandinavia. This indicates that the current European winter warming cannot be explained by changed frequencies of the SLP patterns alone, but to a larger degree by changed characteristics of the patterns themselves. Potential sources of within-type variations are discussed.

Variation of saturation effect in the ionospheric F2 critical frequency at low latitude

NASA Astrophysics Data System (ADS)

Ikubanni, S. O.; Adeniyi, J. O.

2013-08-01

Saturation in the dependence of foF2 on solar flux is a phenomenon more pronounced in the equatorial ionization anomaly region. The phenomenon was observed in the relationship between the F2 critical frequency (foF2) and any solar indices. Using a two-segmented regression fit on data from an African low latitude station (Geographical Latitude 12.4°N; Geomagnetic latitude 3.5°N), saturation features from the dependence of foF2 on solar radio flux (F10.7) was studied. Diurnal and seasonal variation were studied for the first time in this low latitude region of the African sector. Significant variations were observed, especially in the solstices. It was observed that saturation effect is closely related to the hourly F2 critical frequency and these results were compared with those from Asian, Australian and the American sectors. The diurnal and seasonal variations find their explanations in the photo-ionization process, the fountain effect, and the pre-reversal enhancement while the seasonal variation was attributed to both the ion drift and thermospheric circulation. Future work with larger volume of data is expected to validate the observations from this study.

Variations in hospitalization rates among nursing home residents: the role of facility and market attributes.

PubMed

Carter, Mary W; Porell, Frank W

2003-04-01

This study examined the contribution of facility-level and area market-level attributes to variations in hospitalization rates among nursing home residents. Three years (1991-1994) of state quarterly Medicaid case-mix reimbursement data from 527 nursing homes (NH) in Massachusetts were linked with Medicare Provider Analysis and Review hospital claims and nursing facility attribute data to produce a longitudinal, analytical file containing 72,319 person-quarter observations. Logistic regression models were used to estimate the influence of facility-level and market-level factors on hospital use, after controlling for individual-level resident attributes, including: NH diagnoses, resident-level quality of care indicators, and diagnostic cost grouping classification from previous hospital stays. Multivariate findings suggest that resident heterogeneity alone does not account for the wide variations in hospitalization rates across nursing homes. Instead, facility characteristics such as profit status, nurse staffing patterns, NH size, chain affiliation, and percentage of Medicaid and Medicare reimbursed days significantly influence NH residents' risk of hospitalization. Broader area market factors also appear to contribute to variations in hospitalization rates. Variations in hospitalization rates may reflect underutilization, as well as overutilization. Continued efforts toward identifying medically necessary hospitalizations are needed.

Tropical rainforests dominate multi-decadal variability of the global carbon cycle

NASA Astrophysics Data System (ADS)

Zhang, X.; Wang, Y. P.; Peng, S.; Rayner, P. J.; Silver, J.; Ciais, P.; Piao, S.; Zhu, Z.; Lu, X.; Zheng, X.

2017-12-01

Recent studies find that inter-annual variability of global atmosphere-to-land CO2 uptake (NBP) is dominated by semi-arid ecosystems. However, the NBP variations at decadal to multi-decadal timescales are still not known. By developing a basic theory for the role of net primary production (NPP) and heterotrophic respiration (Rh) on NBP and applying it to 100-year simulations of terrestrial ecosystem models forced by observational climate, we find that tropical rainforests dominate the multi-decadal variability of global NBP (48%) rather than the semi-arid lands (35%). The NBP variation at inter-annual timescales is almost 90% contributed by NPP, but across longer timescales is progressively controlled by Rh that constitutes the response from the NPP-derived soil carbon input (40%) and the response of soil carbon turnover rates to climate variability (60%). The NBP variations of tropical rainforests is modulated by the ENSO and the PDO through their significant influences on temperature and precipitation at timescales of 2.5-7 and 25-50 years, respectively. This study highlights the importance of tropical rainforests on the multi-decadal variability of global carbon cycle, suggesting that we need to carefully differentiate the effect of NBP long-term fluctuations associated with ocean-related climate modes on the long-term trend in land sink.

Does Litter Size Variation Affect Models of Terrestrial Carnivore Extinction Risk and Management?

PubMed Central

Devenish-Nelson, Eleanor S.; Stephens, Philip A.; Harris, Stephen; Soulsbury, Carl; Richards, Shane A.

2013-01-01

Background Individual variation in both survival and reproduction has the potential to influence extinction risk. Especially for rare or threatened species, reliable population models should adequately incorporate demographic uncertainty. Here, we focus on an important form of demographic stochasticity: variation in litter sizes. We use terrestrial carnivores as an example taxon, as they are frequently threatened or of economic importance. Since data on intraspecific litter size variation are often sparse, it is unclear what probability distribution should be used to describe the pattern of litter size variation for multiparous carnivores. Methodology/Principal Findings We used litter size data on 32 terrestrial carnivore species to test the fit of 12 probability distributions. The influence of these distributions on quasi-extinction probabilities and the probability of successful disease control was then examined for three canid species – the island fox Urocyon littoralis, the red fox Vulpes vulpes, and the African wild dog Lycaon pictus. Best fitting probability distributions differed among the carnivores examined. However, the discretised normal distribution provided the best fit for the majority of species, because variation among litter-sizes was often small. Importantly, however, the outcomes of demographic models were generally robust to the distribution used. Conclusion/Significance These results provide reassurance for those using demographic modelling for the management of less studied carnivores in which litter size variation is estimated using data from species with similar reproductive attributes. PMID:23469140

Major Variations in HIV-1 Capsid Assembly Morphologies Involve Minor Variations in Molecular Structures of Structurally Ordered Protein Segments*

PubMed Central

Lu, Jun-Xia; Bayro, Marvin J.; Tycko, Robert

2016-01-01

We present the results of solid state nuclear magnetic resonance (NMR) experiments on HIV-1 capsid protein (CA) assemblies with three different morphologies, namely wild-type CA (WT-CA) tubes with 35–60 nm diameters, planar sheets formed by the Arg18-Leu mutant (R18L-CA), and R18L-CA spheres with 20–100 nm diameters. The experiments are intended to elucidate molecular structural variations that underlie these variations in CA assembly morphology. We find that multidimensional solid state NMR spectra of 15N,13C-labeled CA assemblies are remarkably similar for the three morphologies, with only small differences in 15N and 13C chemical shifts, no significant differences in NMR line widths, and few differences in the number of detectable NMR cross-peaks. Thus, the pronounced differences in morphology do not involve major differences in the conformations and identities of structurally ordered protein segments. Instead, morphological variations are attributable to variations in conformational distributions within disordered segments, which do not contribute to the solid state NMR spectra. Variations in solid state NMR signals from certain amino acid side chains are also observed, suggesting differences in the intermolecular dimerization interface between curved and planar CA lattices, as well as possible differences in intramolecular helix-helix packing. PMID:27129282

The impact of family structure transitions on youth achievement: evidence from the children of the NLSY79.

PubMed

Aughinbaugh, Alison; Pierret, Charles R; Rothstein, Donna S

2005-08-01

We investigated the sensitivity of measures of cognitive ability and socioemotional development to changes in parents' marital status using data from the National Longitudinal Survey of Youth, 1979. We used several scores for each assessment, taken at different times relative to parents' marital transitions, which allowed us to trace the effects starting up to five years before a parent's change in marital status and continuing for up to six years afterward. It also allowed us to correct for the unobserved heterogeneity of the transition and nontransition samples by controlling for the child's fixed effect in estimating the time path of his or her response to the transition. We found that children from families with both biological parents scored significantly better on the BPI and the PIAT-math and PIAT-reading assessments than did children from nonintact families. However, much of the difference disappeared when we controlled for background variables. Furthermore, when we controlled for child fixed effects, we did not find significant longitudinal variation in these scores over long periods that encompass the marital transition. This finding suggests that most of the variation is due to cross-sectional differences and is not a result of marital transitions per se.

Measurements of Kepler Planet Masses and Eccentricities from Transit Timing Variations: Analytic and N-body Results

NASA Astrophysics Data System (ADS)

Hadden, Sam; Lithwick, Yoram

2015-12-01

Several Kepler planets reside in multi-planet systems where gravitational interactions result in transit timing variations (TTVs) that provide exquisitely sensitive probes of their masses of and orbits. Measuring these planets' masses and orbits constrains their bulk compositions and can provide clues about their formation. However, inverting TTV measurements in order to infer planet properties can be challenging: it involves fitting a nonlinear model with a large number of parameters to noisy data, often with significant degeneracies between parameters. I present results from two complementary approaches to TTV inversion: Markov chain Monte Carlo simulations that use N-body integrations to compute transit times and a simplified analytic model for computing the TTVs of planets near mean motion resonances. The analytic model allows for straightforward interpretations of N-body results and provides an independent estimate of parameter uncertainties that can be compared to MCMC results which may be sensitive to factors such as priors. We have conducted extensive MCMC simulations along with analytic fits to model the TTVs of dozens of Kepler multi-planet systems. We find that the bulk of these sub-Jovian planets have low densities that necessitate significant gaseous envelopes. We also find that the planets' eccentricities are generally small but often definitively non-zero.

Heritable Variation for Sex Ratio under Environmental Sex Determination in the Common Snapping Turtle (Chelydra Serpentina)

PubMed Central

Janzen, F. J.

1992-01-01

The magnitude of quantitative genetic variation for primary sex ratio was measured in families extracted from a natural population of the common snapping turtle (Chelydra serpentina), which possesses temperature-dependent sex determination (TSD). Eggs were incubated at three temperatures that produced mixed sex ratios. This experimental design provided estimates of the heritability of sex ratio in multiple environments and a test of the hypothesis that genotype X environment (G X E) interactions may be maintaining genetic variation for sex ratio in this population of C. serpentina. Substantial quantitative genetic variation for primary sex ratio was detected in all experimental treatments. These results in conjunction with the occurrence of TSD in this species provide support for three critical assumptions of Fisher's theory for the microevolution of sex ratio. There were statistically significant effects of family and incubation temperature on sex ratio, but no significant interaction was observed. Estimates of the genetic correlations of sex ratio across environments were highly positive and essentially indistinguishable from +1. These latter two findings suggest that G X E interaction is not the mechanism maintaining genetic variation for sex ratio in this system. Finally, although substantial heritable variation exists for primary sex ratio of C. serpentina under constant temperatures, estimates of the effective heritability of primary sex ratio in nature are approximately an order of magnitude smaller. Small effective heritability and a long generation time in C. serpentina imply that evolution of sex ratios would be slow even in response to strong selection by, among other potential agents, any rapid and/or substantial shifts in local temperatures, including those produced by changes in the global climate. PMID:1592234

Neural Activity Patterns in the Human Brain Reflect Tactile Stickiness Perception.

PubMed

Kim, Junsuk; Yeon, Jiwon; Ryu, Jaekyun; Park, Jang-Yeon; Chung, Soon-Cheol; Kim, Sung-Phil

2017-01-01

Our previous human fMRI study found brain activations correlated with tactile stickiness perception using the uni-variate general linear model (GLM) (Yeon et al., 2017). Here, we conducted an in-depth investigation on neural correlates of sticky sensations by employing a multivoxel pattern analysis (MVPA) on the same dataset. In particular, we statistically compared multi-variate neural activities in response to the three groups of sticky stimuli: A supra-threshold group including a set of sticky stimuli that evoked vivid sticky perception; an infra-threshold group including another set of sticky stimuli that barely evoked sticky perception; and a sham group including acrylic stimuli with no physically sticky property. Searchlight MVPAs were performed to search for local activity patterns carrying neural information of stickiness perception. Similar to the uni-variate GLM results, significant multi-variate neural activity patterns were identified in postcentral gyrus, subcortical (basal ganglia and thalamus), and insula areas (insula and adjacent areas). Moreover, MVPAs revealed that activity patterns in posterior parietal cortex discriminated the perceptual intensities of stickiness, which was not present in the uni-variate analysis. Next, we applied a principal component analysis (PCA) to the voxel response patterns within identified clusters so as to find low-dimensional neural representations of stickiness intensities. Follow-up clustering analyses clearly showed separate neural grouping configurations between the Supra- and Infra-threshold groups. Interestingly, this neural categorization was in line with the perceptual grouping pattern obtained from the psychophysical data. Our findings thus suggest that different stickiness intensities would elicit distinct neural activity patterns in the human brain and may provide a neural basis for the perception and categorization of tactile stickiness.

Patterns of seasonality and group membership characterize the gut microbiota in a longitudinal study of wild Verreaux's sifakas (Propithecus verreauxi).

PubMed

Springer, Andrea; Fichtel, Claudia; Al-Ghalith, Gabriel A; Koch, Flávia; Amato, Katherine R; Clayton, Jonathan B; Knights, Dan; Kappeler, Peter M

2017-08-01

The intestinal microbiota plays a major role in host development, metabolism, and health. To date, few longitudinal studies have investigated the causes and consequences of microbiota variation in wildlife, although such studies provide a comparative context for interpreting the adaptive significance of findings from studies on humans or captive animals. Here, we investigate the impact of seasonality, diet, group membership, sex, age, and reproductive state on gut microbiota composition in a wild population of group-living, frugi-folivorous primates, Verreaux's sifakas ( Propithecus verreauxi ). We repeatedly sampled 32 individually recognizable animals from eight adjacent groups over the course of two different climatic seasons. We used high-throughput sequencing of the 16S rRNA gene to determine the microbiota composition of 187 fecal samples. We demonstrate a clear pattern of seasonal variation in the intestinal microbiota, especially affecting the Firmicutes-Bacteroidetes ratio, which may be driven by seasonal differences in diet. The relative abundances of certain polysaccharide-fermenting taxa, for example, Lachnospiraceae, were correlated with fruit and fiber consumption. Additionally, group membership influenced microbiota composition independent of season, but further studies are needed to determine whether this pattern is driven by group divergences in diet, social contacts, or genetic factors. In accordance with findings in other wild mammals and primates with seasonally fluctuating food availability, we demonstrate seasonal variation in the microbiota of wild Verreaux's sifakas, which may be driven by food availability. This study adds to mounting evidence that variation in the intestinal microbiota may play an important role in the ability of primates to cope with seasonal variation in food availability.

Neural Activity Patterns in the Human Brain Reflect Tactile Stickiness Perception

PubMed Central

Kim, Junsuk; Yeon, Jiwon; Ryu, Jaekyun; Park, Jang-Yeon; Chung, Soon-Cheol; Kim, Sung-Phil

2017-01-01

Our previous human fMRI study found brain activations correlated with tactile stickiness perception using the uni-variate general linear model (GLM) (Yeon et al., 2017). Here, we conducted an in-depth investigation on neural correlates of sticky sensations by employing a multivoxel pattern analysis (MVPA) on the same dataset. In particular, we statistically compared multi-variate neural activities in response to the three groups of sticky stimuli: A supra-threshold group including a set of sticky stimuli that evoked vivid sticky perception; an infra-threshold group including another set of sticky stimuli that barely evoked sticky perception; and a sham group including acrylic stimuli with no physically sticky property. Searchlight MVPAs were performed to search for local activity patterns carrying neural information of stickiness perception. Similar to the uni-variate GLM results, significant multi-variate neural activity patterns were identified in postcentral gyrus, subcortical (basal ganglia and thalamus), and insula areas (insula and adjacent areas). Moreover, MVPAs revealed that activity patterns in posterior parietal cortex discriminated the perceptual intensities of stickiness, which was not present in the uni-variate analysis. Next, we applied a principal component analysis (PCA) to the voxel response patterns within identified clusters so as to find low-dimensional neural representations of stickiness intensities. Follow-up clustering analyses clearly showed separate neural grouping configurations between the Supra- and Infra-threshold groups. Interestingly, this neural categorization was in line with the perceptual grouping pattern obtained from the psychophysical data. Our findings thus suggest that different stickiness intensities would elicit distinct neural activity patterns in the human brain and may provide a neural basis for the perception and categorization of tactile stickiness. PMID:28936171

Mothers may shape the variations in social organization among gorillas

PubMed Central

Gray, Maryke; Breuer, Thomas; Manguette, Marie; Stokes, Emma J.; Uwingeli, Prosper; Mburanumwe, Innocent; Kagoda, Edwin; Robbins, Martha M.

2016-01-01

When mothers continue to support their offspring beyond infancy, they can influence the fitness of those offspring, the strength of social relationships within their groups, and the life-history traits of their species. Using up to 30 years of demographic data from 58 groups of gorillas in two study sites, this study extends such findings by showing that mothers may also contribute to differences in social organization between closely related species. Female mountain gorillas remained with their sons for significantly longer than western gorillas, which may explain why male philopatry and multimale groups are more common among mountain gorillas. The presence of the putative father and other familiar males did not vary significantly between species, and we found only limited support for the socio-ecological theory that the distribution of adult males is influenced by the distribution of females. Within each gorilla species, variations in those distributions may also reflect the different stages in the typical life cycle of a group. Collectively, our results highlight the potentially far-reaching consequences of maternal support that extends beyond infancy, and they illustrate the opportunity to incorporate additional factors into phylogenetic analyses of variations in social organization, including studies of human evolution. PMID:27853570

Regional seasonal warming anomalies and land-surface feedbacks

NASA Astrophysics Data System (ADS)

Coffel, E.; Horton, R. M.

2017-12-01

Significant seasonal variations in warming are projected in some regions, especially central Europe, the southeastern U.S., and central South America. Europe in particular may experience up to 2°C more warming during June, July, and August than in the annual mean, enhancing the risk of extreme summertime heat. Previous research has shown that heat waves in Europe and other regions are tied to seasonal soil moisture variations, and that in general land-surface feedbacks have a strong effect on seasonal temperature anomalies. In this study, we show that the seasonal anomalies in warming are also due in part to land-surface feedbacks. We find that in regions with amplified warming during the hot season, surface soil moisture levels generally decline and Bowen ratios increase as a result of a preferential partitioning of incoming energy into sensible vs. latent. The CMIP5 model suite shows significant variability in the strength of land-atmosphere coupling and in projections of future precipitation and soil moisture. Due to the dependence of seasonal warming on land-surface processes, these inter-model variations influence the projected summertime warming amplification and contribute to the uncertainty in projections of future extreme heat.

GxG epistasis in growth and condition and the maintenance of genetic polymorphism in Gambusia holbrooki.

PubMed

Culumber, Zachary W; Kraft, Brittany; Lemakos, Valerie; Hoffner, Erika; Travis, Joseph; Hughes, Kimberly A

2018-05-01

Theory on indirect genetic effects (IGEs) indicates that variation in the genetic composition of social groups can generate GxG epistasis that may promote the evolution of stable polymorphisms. Using a livebearing fish with a genetic polymorphism in coloration and associated behavioral differences, we tested whether genotypes of social partners interacted with focal individual genotypes to influence growth and condition over 16 weeks of development. We found that IGEs had a significant influence on patterns of feeding, regardless of focal fish genotype. There was no influence of social environment on juvenile length, but there was significant GxG epistasis for body condition. Each focal juvenile was in better condition when its own genotype was not present in adult social partners. These data are consistent with negative frequency-dependent selection in which each morph performs better when it is rare. Neither variation in feeding nor activity-related behaviors explained variation in body condition, suggesting that GxG epistasis for condition was caused by physiological differences between the two genotypes. These findings indicate that GxG epistasis in a given polymorphism can generate fitness landscapes that contribute to the maintenance of that polymorphism and to maintenance of genetic variation for additional fitness-related traits. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

OXTR polymorphism predicts social relationships through its effects on social temperament.

PubMed

Creswell, Kasey G; Wright, Aidan G C; Troxel, Wendy M; Ferrell, Robert E; Flory, Janine D; Manuck, Stephen B

2015-06-01

Humans have a fundamental need for strong interpersonal bonds, yet individuals differ appreciably in their degree of social integration. That these differences are also substantially heritable has spurred interest in biological mechanisms underlying the quality and quantity of individuals' social relationships. We propose that polymorphic variation in the oxytocin receptor gene (OXTR) associates with complex social behaviors and social network composition through intermediate effects on negative affectivity and the psychological processing of socially relevant information. We tested a hypothesized social cascade from the molecular level (OXTR variation) to the social environment, through negative affectivity and inhibited sociality, in a sample of 1295 men and women of European American (N = 1081) and African American (N = 214) ancestry. Compared to European Americans having any T allele of rs1042778, individuals homozygous for the alternate G allele reported significantly lower levels of negative affectivity and inhibited sociality, which in turn predicted significantly higher levels of social support and a larger/more diverse social network. Moreover, the effect of rs1042778 variation on social support was fully accounted for by associated differences in negative affectivity and inhibited sociality. Results replicated in the African American sample. Findings suggest that OXTR variation modulates levels of social support via proximal impacts on individual temperament. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Long term (1997-2014) spatial and temporal variations in nitrogen in Dongting Lake, China

PubMed Central

Tian, Zebin; Zheng, Binghui; Wang, Lijing; Li, Liqiang; Wang, Xing; Li, Hong; Norra, Stefan

2017-01-01

In order to protect the water quality of Dongting Lake, it is significant to find out its nitrogen pollution characteristics. Using long-term monthly to seasonally data (1997–2014), we investigated the spatial and temporal variations in nitrogen in Dongting Lake, the second largest freshwater lake in China. The average concentrations of total nitrogen (TN) in the eastern, southern, and western parts of the lake were 1.77, 1.56, and 1.35 mg/L, respectively, in 2014. TN pollution was generally worse in the southern area than in the western area. Concentrations showed temporal variation, and were significantly higher during the dry season than during the wet season. Based on the concentration and growth rate of TN, three different stages were identified in the long term lake data, from 1997 to 2002, from 2003 to 2008, and from 2009 to 2014, during which the concentrations and the growth rate ranged from 1.09–1.51 mg/L and 22.09%-40.03%, 1.05–1.57 mg/L and -9.05%-7.74%, and 1.68–2.02 mg/L and 57.99%-60.41%, respectively. The main controls on the lake water TN concentrations were the quality and quantity of the lake inflows, spatial and temporal variations in hydrodynamic conditions within the lake (flow velocity, flow direction), and point and nonpoint inputs from human activities. Diffuse nutrient losses from agricultural land are a significant contributor. As a priority, the local government should aim to control the pollutant inputs from upstream and non-point nutrient losses from land. PMID:28166245

Snow cover variations in Gansu, China, from 2002 to 2013

NASA Astrophysics Data System (ADS)

Liu, Xun; Ke, Chang-Qing; Shao, Zhu-De

2015-11-01

Gansu is an inland province located in the northwest of China with an arid to semi-arid climate and a developed animal husbandry. Snowmelt in Gansu is an important source of water for rivers and plays an important role in ecological environment and social-economic activities. In this study, Moderate Resolution Imaging Spectroradiometer (MODIS) 8-day composite snow products MOD10A2 and MYD10A2 are combined to analyse snow cover variations during the snow season (October to March) period from 2002 to 2013. We define the snow area percentage (SAP) and snow cover occurrence percentage (SCOP) to analyse the spatial and temporal characteristics of the snow cover variation in Gansu. In addition, we apply the Mann-Kendall test to verify the SAP inter-annual variation. The results indicate that the SAP in Gansu remained above 5 % with three peaks in November, December and January. SAP varies a lot in the four sub-regions of Gansu, with the highest in the Gannan Plateau sub-region and the lowest in the Longzhong Loess Plateau sub-region in most of the snow seasons examined. The SCOP is high in the southwest mountains and low in the northeast Gobi and desert. The SCOP is highly related to elevation in most of Gansu, with an exception in the high mountains. In the Hexi Desert and oasis region, the SAP significantly decreases during the snow season, particularly in February and March. We find that there are a significantly negative correlation between SCOP and temperature during the snow season and a significantly positive correlation between SCOP and precipitation in December.

Codiversification of gastrointestinal microbiota and phylogeny in passerines is not explained by ecological divergence.

PubMed

Kropáčková, Lucie; Těšický, Martin; Albrecht, Tomáš; Kubovčiak, Jan; Čížková, Dagmar; Tomášek, Oldřich; Martin, Jean-François; Bobek, Lukáš; Králová, Tereza; Procházka, Petr; Kreisinger, Jakub

2017-10-01

Vertebrate gut microbiota (GM) is comprised of a taxonomically diverse consortium of symbiotic and commensal microorganisms that have a pronounced effect on host physiology, immune system function and health status. Despite much research on interactions between hosts and their GM, the factors affecting inter- and intraspecific GM variation in wild populations are still poorly known. We analysed data on faecal microbiota composition in 51 passerine species (319 individuals) using Illumina MiSeq sequencing of bacterial 16S rRNA (V3-V4 variable region). Despite pronounced interindividual variation, GM composition exhibited significant differences at the interspecific level, accounting for approximately 20%-30% of total GM variation. We also observed a significant correlation between GM composition divergence and host's phylogenetic divergence, with strength of correlation higher than that of GM vs. ecological or life history traits and geographic variation. The effect of host's phylogeny on GM composition was significant, even after statistical control for these confounding factors. Hence, our data do not support codiversification of GM and passerine phylogeny solely as a by-product of their ecological divergence. Furthermore, our findings do not support that GM vs. host's phylogeny codiversification is driven primarily through trans-generational GM transfer as the GM vs. phylogeny correlation does not increase with higher sequence similarity used when delimiting operational taxonomic units. Instead, we hypothesize that the GM vs. phylogeny correlation may arise as a consequence of interspecific divergence of genes that directly or indirectly modulate composition of GM. © 2017 John Wiley & Sons Ltd.

Disparity in Dental Coverage Among Older Adult Populations: A Comparative Analysis Across Selected European Countries and the United States

PubMed Central

Manski, Richard; Moeller, John; Chen, Haiyan; Widström, Eeva; Lee, Jinkook; Listl, Stefan

2014-01-01

Background Insurance against the cost risks associated with prevention and treatment of oral diseases can reduce inequalities in dental care use and oral health. The purpose of this study was to examine the extent of variation in dental insurance coverage for older adult populations within and between the United States and various European countries. Method The analyses relied on 2006/2007 data from the Survey of Health, Ageing, and Retirement in Europe (SHARE) and 2004-2006 data from of the Health and Retirement Study (HRS) in the United States for respondents aged 51 years and older. A series of logistic regression models was estimated to identify disparities in dental coverage. Results The highest extent of significant insurance differences between various population subgroups was found for the United States. In comparison with countries belonging to the Eastern and Southern welfare state regimes, a lower number of significant coverage differences occurred for Scandinavian countries. Countries categorized as having comprehensive public insurance coverage showed a tendency towards less insurance variation within their populations than countries categorized as not having comprehensive public coverage, exceptions being Poland and Switzerland. Conclusions The findings of the present study suggest that significant variations in dental coverage exist within all elderly populations examined and the extent of inequalities also differs between countries. By and large, the observed variations corroborate the perception that population dental coverage is more equally distributed under public subsidy. This could be relevant information for decision makers who seek to improve policies towards more equitable dental coverage. PMID:25363376

Variation of the interphase heterochromatin in Artemia (Crustacea, Anostraca) of the Americas is related to changes in nuclear size and ionic composition of hipersaline habitats.

PubMed

Parraguez, M; Gajardo, G

2017-01-01

The populations of Artemia (or brine shrimp) from the Americas exhibit a wide variation in the amount of interphase heterochromatin. There is interest in understanding how this variation affects different parameters, from the cellular to the organismal levels. This should help to clarify the ability of this organism to tolerate brine habitats regularly subject to strong abiotic changes. In this study, we assessed the amount of interphase heterochromatin per nucleus based on chromocenter number (N-CHR) and relative area of chromocenter (R-CHR) in two species of Artemia, A. franciscana (Kellog, 1906) (n=9 populations) and A. persimilis (Piccinelli and Prosdocimi, 1968) (n=3 populations), to investigate the effect on nuclear size (S-NUC). The relationship of the R-CHR parameter with the ionic composition (IC) of brine habitats was also analysed. Our results indicate a significant variation in the amount of heterochromatin both within and between species (ANOVA, p<0.001). The heterochromatin varied from 0.81 ± 1.17 to 12.58 ± 3.78 and from 0.19 ± 0.34% to 11.78 ± 3.71% across all populations, for N-CHR and R-CHR parameters, respectively. N-CHR showed less variation than R-CHR (variation index 15.5-fold vs. 62-fold). At least five populations showed a significant association (p<0.05) between R-CHR and S-NUC, either with negative (four populations, r= from -0.643 to -0.443), or positive (one population, r= 0.367) values.Within each species, there were no significant associations between both parameters (p>0.05). The R-CHR and IC parameters were associated significantly for the magnesium ion (r= 0.496, p<0.05) and also for the chloride, sodium and calcium ions (r = from -0.705 to -0.478, p<0.05). At species level, a significant association between both parameters was also found in A. franciscana populations, for the sulphate and calcium ions, in contrast to A. persimilis. These findings suggest that the amount of interphase heterochromatin modifies the nuclear size in Artemia. Our data also indicate that change in the amount of interphase heterochromatin is in line with the ionic composition of brines. This would be a species-specific phenomenon, whose occurrence may be involved in the ability of this organism to survive in these environments.

Factors significantly related to science achievement of Malaysian middle school students: An analysis of TIMSS 1999 data

NASA Astrophysics Data System (ADS)

Mokshein, Siti Eshah

The importance of science and technology in the global economy has led to growing emphasis on math and science achievement all over the world. In this study, I seek to identify variables at the student-level and school-level that account for the variation in science achievement of the eighth graders in Malaysia. Using the Third International Math and Science Study (TIMSS) 1999 for Malaysia, a series of HLM analysis was performed. Results indicate that (1) variation in overall science achievement is greater between schools than within schools; (2) both the selected student-level and school-level factors are Important in explaining the variation in the eight graders' achievement In science; (3) the selected student-level variables explain about 13% of the variation in students' achievement within schools, but as an aggregate, they account for a much larger proportion of the between-school variance; (4) the selected school-level variables account for about 55% of the variation between schools; (5) within schools, the effects of self-concept In science, awareness of the social implications of science, gender, and home educational resources are significantly related to achievement; (6) the effects of self-concept in science and awareness of social implications of science are significant even after controlling for the effects of SES; (7) between schools, the effects of the mean of home educational resources, mean of parents' education, mean of awareness of the social implications of science, and emphasis on conducting experiments are significantly related to achievement; (8) the effects of SES variables explain about 50% of the variation in the school means achievement; and (9) the effects of emphasis on conducting experiments on achievement are significant even after controlling for the effects of SES. Since it is hard to change the society, it is recommended that efforts to Improve science achievement be focused more at the school-level, concentrating on variables that can be changed. This includes Increasing students' awareness of the social Implications of science and improving students' self-concepts In science, strengthening evaluation systems, and finding ways to compensate for the lack of home educational resources among disadvantaged students. The study further suggests that emphasis be given to proper implementation of science experiments. Besides, the prominent effects of SES variables on the school mean achievement is something worthwhile to be further researched.

Metatarsal Shape and Foot Type: A Geometric Morphometric Analysis.

PubMed

Telfer, Scott; Kindig, Matthew W; Sangeorzan, Bruce J; Ledoux, William R

2017-03-01

Planus and cavus foot types have been associated with an increased risk of pain and disability. Improving our understanding of the geometric differences between bones in different foot types may provide insights into injury risk profiles and have implications for the design of musculoskeletal and finite-element models. In this study, we performed a geometric morphometric analysis on the geometry of metatarsal bones from 65 feet, segmented from computed tomography (CT) scans. These were categorized into four foot types: pes cavus, neutrally aligned, asymptomatic pes planus, and symptomatic pes planus. Generalized procrustes analysis (GPA) followed by permutation tests was used to determine significant shape differences associated with foot type and sex, and principal component analysis was used to find the modes of variation for each metatarsal. Significant shape differences were found between foot types for all the metatarsals (p < 0.01), most notably in the case of the second metatarsal which showed significant pairwise differences across all the foot types. Analysis of the principal components of variation showed pes cavus bones to have reduced cross-sectional areas in the sagittal and frontal planes. The first (p = 0.02) and fourth metatarsals (p = 0.003) were found to have significant sex-based differences, with first metatarsals from females shown to have reduced width, and fourth metatarsals from females shown to have reduced frontal and sagittal plane cross-sectional areas. Overall, these findings suggest that metatarsal bones have distinct morphological characteristics that are associated with foot type and sex, with implications for our understanding of anatomy and numerical modeling of the foot.

Embracing heterothermic diversity: non-stationary waveform analysis of temperature variation in endotherms.

PubMed

Levesque, Danielle L; Menzies, Allyson K; Landry-Cuerrier, Manuelle; Larocque, Guillaume; Humphries, Murray M

2017-07-01

Recent research is revealing incredible diversity in the thermoregulatory patterns of wild and captive endotherms. As a result of these findings, classic thermoregulatory categories of 'homeothermy', 'daily heterothermy', and 'hibernation' are becoming harder to delineate, impeding our understanding of the physiological and evolutionary significance of variation within and around these categories. However, we lack a generalized analytical approach for evaluating and comparing the complex and diversified nature of the full breadth of heterothermy expressed by individuals, populations, and species. Here we propose a new approach that decomposes body temperature time series into three inherent properties-waveform, amplitude, and period-using a non-stationary technique that accommodates the temporal variability of body temperature patterns. This approach quantifies circadian and seasonal variation in thermoregulatory patterns, and uses the distribution of observed thermoregulatory patterns as a basis for intra- and inter-specific comparisons. We analyse body temperature time series from multiple species, including classical hibernators, tropical heterotherms, and homeotherms, to highlight the approach's general usefulness and the major axes of thermoregulatory variation that it reveals.

Fluctuations in food supply drive recruitment variation in a marine fish.

PubMed

Okamoto, Daniel K; Schmitt, Russell J; Holbrook, Sally J; Reed, Daniel C

2012-11-22

Reproductive rates and survival of young in animal populations figure centrally in generating management and conservation strategies. Model systems suggest that food supply can drive these often highly variable properties, yet for many wild species, quantifying such effects and assessing their implications have been challenging. We used spatially explicit time series of a well-studied marine reef fish (black surfperch Embiotoca jacksoni) and its known prey resources to evaluate the extent to which fluctuations in food supply influenced production of young by adults and survival of young to subadulthood. Our analyses reveal: (i) variable food available to both adults and to their offspring directly produced an order of magnitude variation in the number of young-of-year (YOY) produced per adult and (ii) food available to YOY produced a similar magnitude of variation in their subsequent survival. We also show that such large natural variation in vital rates can significantly alter decision thresholds (biological reference points) important for precautionary management. These findings reveal how knowledge of food resources can improve understanding of population dynamics and reduce risk of overharvest by more accurately identifying periods of low recruitment.

Molar intercuspal dimensions: genetic input to phenotypic variation.

PubMed

Townsend, G; Richards, L; Hughes, T

2003-05-01

Molecular studies indicate that epigenetic events are important in determining how the internal enamel epithelium folds during odontogenesis. Since this process of folding leads to the subsequent arrangement of cusps on molar teeth, we hypothesized that intercuspal distances of human molar teeth would display greater phenotypic variation but lower heritabilities than overall crown diameters. Intercuspal distances and maximum crown diameters were recorded from digitized images of dental casts in 100 monozygotic and 74 dizygotic twin pairs. Intercuspal distances displayed less sexual dimorphism in mean values but greater relative variability and fluctuating asymmetry than overall crown measures. Correlations between intercuspal distances and overall crown measures were low. Models incorporating only environmental effects accounted for observed variation in several intercuspal measures. For those intercuspal variables displaying significant additive genetic variance, estimates of heritability ranged from 43 to 79%, whereas those for overall crown size were higher generally, ranging from 60 to 82%. Our finding of high phenotypic variation in intercuspal distances with only moderate genetic contribution is consistent with substantial epigenetic influence on the progressive folding of the internal enamel epithelium, following formation of the primary and secondary enamel knots.

Seasonal and Geographical Variation of Dengue Vectors in Narathiwat, South Thailand

PubMed Central

Boonklong, Ornanong; Bhumiratana, Adisak

2016-01-01

Using GIS-based land use map for the urban-rural division (the relative ratio of population density adjusted to relatively Aedes-infested land area), we demonstrated significant independent observations of seasonal and geographical variation of Aedes aegypti and Aedes albopictus vectors between Muang Narathiwat district (urban setting) and neighbor districts (rural setting) of Narathiwat, Southern Thailand, based on binomial distribution of Aedes vectors in water-holding containers (water storage containers, discarded receptacles, miscellaneous containers, and natural containers). The distribution of Aedes vectors was influenced seasonally by breeding outdoors rather than indoors in all 4 containers. Accordingly, both urban and rural settings elicited significantly seasonal (wet versus dry) distributions of Ae. aegypti larvae observed in water storage containers (P = 0.001 and P = 0.002) and natural containers (P = 0.016 and P = 0.015), whereas, in rural setting, the significant difference was observed in discarded receptacles (P = 0.028) and miscellaneous containers (P < 0.001). Seasonal distribution of Ae. albopictus larvae in any containers in urban setting was not remarkably noticed, whereas, in rural setting, the significant difference was observed in water storage containers (P = 0.007) and discarded receptacles (P < 0.001). Moreover, the distributions of percentages of container index for Aedes-infested households in dry season were significantly lower than that in other wet seasons, P = 0.034 for urban setting and P = 0.001 for rural setting. Findings suggest that seasonal and geographical variation of Aedes vectors affect the infestation in those containers in human inhabitations and surroundings. PMID:27437001

High level of molecular and phenotypic biodiversity in Jatropha curcas from Central America compared to Africa, Asia and South America

PubMed Central

2014-01-01

Background The main bottleneck to elevate jatropha (Jatropha curcas L.) from a wild species to a profitable biodiesel crop is the low genetic and phenotypic variation found in different regions of the world, hampering efficient plant breeding for productivity traits. In this study, 182 accessions from Asia (91), Africa (35), South America (9) and Central America (47) were evaluated at genetic and phenotypic level to find genetic variation and important traits for oilseed production. Results Genetic variation was assessed with SSR (Simple Sequence Repeat), TRAP (Target Region Amplification Polymorphism) and AFLP (Amplified fragment length polymorphism) techniques. Phenotypic variation included seed morphological characteristics, seed oil content and fatty acid composition and early growth traits. Jaccard’s similarity and cluster analysis by UPGM (Unweighted Paired Group Method) with arithmetic mean and PCA (Principle Component Analysis) indicated higher variability in Central American accessions compared to Asian, African and South American accessions. Polymorphism Information Content (PIC) values ranged from 0 to 0.65. In the set of Central American accessions. PIC values were higher than in other regions. Accessions from the Central American population contain alleles that were not found in the accessions from other populations. Analysis of Molecular Variance (AMOVA; P < 0.0001) indicated high genetic variation within regions (81.7%) and low variation across regions (18.3%). A high level of genetic variation was found on early growth traits and on components of the relative growth rate (specific leaf area, leaf weight, leaf weight ratio and net assimilation rate) as indicated by significant differences between accessions and by the high heritability values (50–88%). The fatty acid composition of jatropha oil significantly differed (P < 0.05) between regions. Conclusions The pool of Central American accessions showed very large genetic variation as assessed by DNA-marker variation compared to accessions from other regions. Central American accessions also showed the highest phenotypic variation and should be considered as the most important source for plant breeding. Some variation in early growth traits was found within a group of accessions from Asia and Africa, while these accessions did not differ in a single DNA-marker, possibly indicating epigenetic variation. PMID:24666927

The Effects of Warming and Nitrogen Addition on Soil Nitrogen Cycling in a Temperate Grassland, Northeastern China

PubMed Central

Ma, Lin-Na; Lü, Xiao-Tao; Liu, Yang; Guo, Ji-Xun; Zhang, Nan-Yi; Yang, Jian-Qin; Wang, Ren-Zhong

2011-01-01

Background Both climate warming and atmospheric nitrogen (N) deposition are predicted to affect soil N cycling in terrestrial biomes over the next century. However, the interactive effects of warming and N deposition on soil N mineralization in temperate grasslands are poorly understood. Methodology/Principal Findings A field manipulation experiment was conducted to examine the effects of warming and N addition on soil N cycling in a temperate grassland of northeastern China from 2007 to 2009. Soil samples were incubated at a constant temperature and moisture, from samples collected in the field. The results showed that both warming and N addition significantly stimulated soil net N mineralization rate and net nitrification rate. Combined warming and N addition caused an interactive effect on N mineralization, which could be explained by the relative shift of soil microbial community structure because of fungal biomass increase and strong plant uptake of added N due to warming. Irrespective of strong intra- and inter-annual variations in soil N mineralization, the responses of N mineralization to warming and N addition did not change during the three growing seasons, suggesting independence of warming and N responses of N mineralization from precipitation variations in the temperate grassland. Conclusions/Significance Interactions between climate warming and N deposition on soil N cycling were significant. These findings will improve our understanding on the response of soil N cycling to the simultaneous climate change drivers in temperate grassland ecosystem. PMID:22096609

Where are the Binaries? Results of a Long-term Search for Radial Velocity Binaries in Proto-planetary Nebulae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hrivnak, Bruce J.; Lu, Wenxian; Steene, Griet Van de

We present the results of an expanded, long-term radial velocity search (25 years) for evidence of binarity in a sample of seven bright proto-planetary nebulae (PPNe). The goal is to investigate the widely held view that the bipolar or point-symmetric shapes of planetary nebulae (PNe) and PPNe are due to binary interactions. Observations from three observatories were combined from 2007 to 2015 to search for variations on the order of a few years and then combined with earlier observations from 1991 to 1995 to search for variations on the order of decades. All seven show velocity variations due to periodicmore » pulsation in the range of 35–135 days. However, in only one PPN, IRAS 22272+5435, did we find even marginal evidence for multi-year variations that might be due to a binary companion. This object shows marginally significant evidence of a two-year period of low semi-amplitude, which could be due to a low-mass companion, and it also displays some evidence of a much longer period of >30 years. The absence of evidence in the other six objects for long-period radial velocity variations due to a binary companion sets significant constraints on the properties of any undetected binary companions: they must be of low mass, ≤0.2 M {sub ⊙}, or long period, >30 years. Thus the present observations do not provide direct support for the binary hypothesis to explain the shapes of PNe and PPNe and severely constrains the properties of any such undetected companions.« less

Dynamics of Hierarchical Urban Green Space Patches and Implications for Management Policy.

PubMed

Yu, Zhoulu; Wang, Yaohui; Deng, Jinsong; Shen, Zhangquan; Wang, Ke; Zhu, Jinxia; Gan, Muye

2017-06-06

Accurately quantifying the variation of urban green space is the prerequisite for fully understanding its ecosystem services. However, knowledge about the spatiotemporal dynamics of urban green space is still insufficient due to multiple challenges that remain in mapping green spaces within heterogeneous urban environments. This paper uses the city of Hangzhou to demonstrate an analysis methodology that integrates sub-pixel mapping technology and landscape analysis to fully investigate the spatiotemporal pattern and variation of hierarchical urban green space patches. Firstly, multiple endmember spectral mixture analysis was applied to time series Landsat data to derive green space coverage at the sub-pixel level. Landscape metric analysis was then employed to characterize the variation pattern of urban green space patches. Results indicate that Hangzhou has experienced a significant loss of urban greenness, producing a more fragmented and isolated vegetation landscape. Additionally, a remarkable amelioration of urban greenness occurred in the city core from 2002 to 2013, characterized by the significant increase of small-sized green space patches. The green space network has been formed as a consequence of new urban greening strategies in Hangzhou. These strategies have greatly fragmented the built-up areas and enriched the diversity of the urban landscape. Gradient analysis further revealed a distinct pattern of urban green space landscape variation in the process of urbanization. By integrating both sub-pixel mapping technology and landscape analysis, our approach revealed the subtle variation of urban green space patches which are otherwise easy to overlook. Findings from this study will help us to refine our understanding of the evolution of heterogeneous urban environments.

Dynamics of Hierarchical Urban Green Space Patches and Implications for Management Policy

PubMed Central

Yu, Zhoulu; Wang, Yaohui; Deng, Jinsong; Shen, Zhangquan; Wang, Ke; Zhu, Jinxia; Gan, Muye

2017-01-01

Accurately quantifying the variation of urban green space is the prerequisite for fully understanding its ecosystem services. However, knowledge about the spatiotemporal dynamics of urban green space is still insufficient due to multiple challenges that remain in mapping green spaces within heterogeneous urban environments. This paper uses the city of Hangzhou to demonstrate an analysis methodology that integrates sub-pixel mapping technology and landscape analysis to fully investigate the spatiotemporal pattern and variation of hierarchical urban green space patches. Firstly, multiple endmember spectral mixture analysis was applied to time series Landsat data to derive green space coverage at the sub-pixel level. Landscape metric analysis was then employed to characterize the variation pattern of urban green space patches. Results indicate that Hangzhou has experienced a significant loss of urban greenness, producing a more fragmented and isolated vegetation landscape. Additionally, a remarkable amelioration of urban greenness occurred in the city core from 2002 to 2013, characterized by the significant increase of small-sized green space patches. The green space network has been formed as a consequence of new urban greening strategies in Hangzhou. These strategies have greatly fragmented the built-up areas and enriched the diversity of the urban landscape. Gradient analysis further revealed a distinct pattern of urban green space landscape variation in the process of urbanization. By integrating both sub-pixel mapping technology and landscape analysis, our approach revealed the subtle variation of urban green space patches which are otherwise easy to overlook. Findings from this study will help us to refine our understanding of the evolution of heterogeneous urban environments. PMID:28587309

Multilevel linear modelling of the response-contingent learning of young children with significant developmental delays.

PubMed

Raab, Melinda; Dunst, Carl J; Hamby, Deborah W

2018-02-27

The purpose of the study was to isolate the sources of variations in the rates of response-contingent learning among young children with multiple disabilities and significant developmental delays randomly assigned to contrasting types of early childhood intervention. Multilevel, hierarchical linear growth curve modelling was used to analyze four different measures of child response-contingent learning where repeated child learning measures were nested within individual children (Level-1), children were nested within practitioners (Level-2), and practitioners were nested within the contrasting types of intervention (Level-3). Findings showed that sources of variations in rates of child response-contingent learning were associated almost entirely with type of intervention after the variance associated with differences in practitioners nested within groups were accounted for. Rates of child learning were greater among children whose existing behaviour were used as the building blocks for promoting child competence (asset-based practices) compared to children for whom the focus of intervention was promoting child acquisition of missing skills (needs-based practices). The methods of analysis illustrate a practical approach to clustered data analysis and the presentation of results in ways that highlight sources of variations in the rates of response-contingent learning among young children with multiple developmental disabilities and significant developmental delays. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Geographic Variation of Amyotrophic Lateral Sclerosis Incidence in New Jersey, 2009–2011

PubMed Central

Henry, Kevin A.; Fagliano, Jerald; Jordan, Heather M.; Rechtman, Lindsay; Kaye, Wendy E.

2015-01-01

Few analyses in the United States have examined geographic variation and socioeconomic disparities in amyotrophic lateral sclerosis (ALS) incidence, because of lack of population-based incidence data. In this analysis, we used population-based ALS data to identify whether ALS incidence clusters geographically and to determine whether ALS risk varies by area-based socioeconomic status (SES). This study included 493 incident ALS cases diagnosed (via El Escorial criteria) in New Jersey between 2009 and 2011. Geographic variation and clustering of ALS incidence was assessed using a spatial scan statistic and Bayesian geoadditive models. Poisson regression was used to estimate the associations between ALS risk and SES based on census-tract median income while controlling for age, sex, and race. ALS incidence varied across and within counties, but there were no statistically significant geographic clusters. SES was associated with ALS incidence. After adjustment for age, sex, and race, the relative risk of ALS was significantly higher (relative risk (RR) = 1.37, 95% confidence interval (CI): 1.02, 1.82) in the highest income quartile than in the lowest. The relative risk of ALS was significantly lower among blacks (RR = 0.57, 95% CI: 0.39, 0.83) and Asians (RR = 0.63, 95% CI: 0.41, 0.97) than among whites. Our findings suggest that ALS incidence in New Jersey appears to be associated with SES and race. PMID:26041711

Purification and identification of 25-hydroxycholesterol in a reptile: Seasonal variation and hormonal regulation.

PubMed

Singh, Varsha; Priyam, Manisha; Tripathy, Mamta; Rai, Umesh

2017-06-01

The present in vitro study, for the first time, demonstrates the production of 25-hydroxycholestrol (25-HC) by testicular macrophages of a non-mammalian vertebrate. The ether extracts of testicular macrophage-conditioned medium (TMCM) were fractionated on a C18 reversed phase high-performance liquid chromatography (HPLC) column using methanol as the mobile phase. The mass spectrometry (MS) fragmentation pattern of HPLC-purified 25-HC was found to be identical to that of authentic 25-HC. Further, a significant seasonal variation in 25-HC concentration was observed with maximal level in regressed and minimal during breeding phase. To understand the hormonal control of 25-HC production, testicular macrophages from regressed phase testes were incubated with 0.5μg/ml of ovine follicle stimulating hormone (FSH) and 0.1, 1 and 10μg/ml of testosterone (T). FSH considerably enhanced 25-HC production by testicular macrophages. In contrast, T markedly inhibited 25-HC production in a dose-dependent manner. In addition, T significantly inhibited FSH-induced 25-HC production, though pre-treatment with T was more effective as compared to post-treatment with T to FSH. Our findings on production, seasonal variation and hormonal control of 25-HC suggest the functional significance of 25-HC in the testis of reptiles. Copyright © 2017 Elsevier Inc. All rights reserved.

Factors Associated with Variations in Population HIV Prevalence across West Africa: Findings from an Ecological Analysis

PubMed Central

Prudden, Holly J.; Beattie, Tara S.; Bobrova, Natalia; Panovska-Griffiths, Jasmina; Mukandavire, Zindoga; Gorgens, Marelize; Wilson, David; Watts, Charlotte H.

2015-01-01

Background Population HIV prevalence across West Africa varies substantially. We assess the national epidemiological and behavioural factors associated with this. Methods National, urban and rural data on HIV prevalence, the percentage of younger (15–24) and older (25–49) women and men reporting multiple (2+) partners in the past year, HIV prevalence among female sex workers (FSWs), men who have bought sex in the past year (clients), and ART coverage, were compiled for 13 countries. An Ecological analysis using linear regression assessed which factors are associated with national variations in population female and male HIV prevalence, and with each other. Findings National population HIV prevalence varies between 0 4–2 9% for men and 0 4–5.6% for women. ART coverage ranges from 6–23%. National variations in HIV prevalence are not shown to be associated with variations in HIV prevalence among FSWs or clients. Instead they are associated with variations in the percentage of younger and older males and females reporting multiple partners. HIV prevalence is weakly negatively associated with ART coverage, implying it is not increased survival that is the cause of variations in HIV prevalence. FSWs and younger female HIV prevalence are associated with client population sizes, especially older men. Younger female HIV prevalence is strongly associated with older male and female HIV prevalence. Interpretation In West Africa, population HIV prevalence is not significantly higher in countries with high FSW HIV prevalence. Our analysis suggests, higher prevalence occurs where more men buy sex, and where a higher percentage of younger women, and older men and women have multiple partnerships. If a sexual network between clients and young females exists, clients may potentially bridge infection to younger females. HIV prevention should focus both on commercial sex and transmission between clients and younger females with multiple partners. PMID:26698854

Spatiotemporal variations in litter mass and their relationships with climate in temperate grassland: A case study from Xilingol grassland, Inner Mongolia (China)

NASA Astrophysics Data System (ADS)

Ren, Hongrui; Zhang, Bei

2018-02-01

Clarifying spatiotemporal variations of litter mass and their relationships with climate factors will advance our understanding of ecosystem structure and functioning in grasslands. Our objective is to investigate the spatiotemporal variations of litter mass in the growing season and their relationships with precipitation and temperature in the Xilingol grassland using MOD09A1 data. With widely used STI (simple tillage index), we firstly estimated the litter mass of Xilingol grassland in the growing season from 2000 to 2014. Then we investigated the variations of litter mass in the growing season at regional and site scales. We further explored the spatiotemporal relationships between litter mass and precipitation and temperature at both scales. The litter mass increased with increasing mean annual precipitation and decreasing mean annual temperature at regional scale. The variations of litter mass at given sites followed quadratic function curves in the growing season, and litter mass generally attained maximums between August 1 and September 1. Positive spatial relationship was observed between litter mass variations and precipitation, and negative spatial relationship was found between litter mass variations and temperature in the growing season. There was no significant relationship between inter-annual variations of litter mass and precipitation and temperature at given sites. Results illustrate that precipitation and temperature are important drivers in shaping ecosystem functioning as reflected in litter mass at regional scale in the Xilingol grassland. Our findings also suggest the action of distinct mechanism in controlling litter mass variations at regional and sites scales.

Individualism, collectivism, and Chinese adolescents' aggression: intracultural variations.

PubMed

Li, Yan; Wang, Mo; Wang, Cixin; Shi, Junqi

2010-01-01

This study examined the relations between cultural values (i.e., individualism and collectivism) and aggression among 460 (234 girls) Chinese adolescents. Conflict level and social status insecurity were examined as potential explaining mechanisms for these relations. The results showed that adolescents' endorsement of collectivism was negatively related to their use of overt and relational aggression as reported by teachers and peers, whereas positive associations were found between the endorsement of individualism and adolescent aggression. Adolescents' conflict level and social status insecurity accounted for a significant part of these associations. Findings of this study demonstrate the importance of examining intracultural variations of cultural values in relation to adolescent aggression as well as the process variables in explaining the relations. (c) 2010 Wiley-Liss, Inc.

Could age modify the effect of genetic variants in IL6 and TNF-α genes in multiple myeloma?

PubMed

Martino, Alessandro; Buda, Gabriele; Maggini, Valentina; Lapi, Francesco; Lupia, Antonella; Di Bello, Domenica; Orciuolo, Enrico; Galimberti, Sara; Barale, Roberto; Petrini, Mario; Rossi, Anna Maria

2012-05-01

Cytokines play a central role in multiple myeloma (MM) pathogenesis thus genetic variations within cytokines coding genes could influence MM susceptibility and therapy outcome. We investigated the impact of 8 SNPs in these genes in 202 MM cases and 235 controls also evaluating their impact on therapy outcome in a subset of 91 patients. Despite the overall negative findings, we found a significant age-modified effect of IL6 and TNF-α SNPs, on MM risk and therapy outcome, respectively. Therefore, this observation suggests that genetic variation in inflammation-related genes could be an important mediator of the complex interplay between ageing and cancer. Copyright © 2012 Elsevier Ltd. All rights reserved.

The relationship between education and levels of trust and tolerance in Europe.

PubMed

Borgonovi, Francesca

2012-03-01

In this article we explore the relationship between education and levels of trust and tolerance in Europe. More specifically we assess whether the relationship between years of schooling and the extent to which individuals trust others in their communities and are tolerant towards immigrants varies across European countries and attempt to identify possible sources of these variations. Findings based on data from the first three rounds of the European Social Survey indicate that the association between education and levels of trust and tolerance varies significantly across countries and that a major source of this variation lies in the way in which individuals react to the level of diversity in the country where they live. © London School of Economics and Political Science 2012.

Genetic variation and gene expression across multiple tissues and developmental stages in a non-human primate

PubMed Central

Jasinska, Anna J.; Zelaya, Ivette; Service, Susan K.; Peterson, Christine B.; Cantor, Rita M.; Choi, Oi-Wa; DeYoung, Joseph; Eskin, Eleazar; Fairbanks, Lynn A.; Fears, Scott; Furterer, Allison E.; Huang, Yu S.; Ramensky, Vasily; Schmitt, Christopher A.; Svardal, Hannes; Jorgensen, Matthew J.; Kaplan, Jay R.; Villar, Diego; Aken, Bronwen L.; Flicek, Paul; Nag, Rishi; Wong, Emily S.; Blangero, John; Dyer, Thomas D.; Bogomolov, Marina; Benjamini, Yoav; Weinstock, George M.; Dewar, Ken; Sabatti, Chiara; Wilson, Richard K.; Jentsch, J. David; Warren, Wesley; Coppola, Giovanni; Woods, Roger P.; Freimer, Nelson B.

2017-01-01

By analyzing multi-tissue gene expression and genome-wide genetic variation data in samples from a vervet monkey pedigree, we generated a transcriptome resource and produced the first catalogue of expression quantitative trait loci (eQTLs) in a non-human primate model. This catalogue contains more genome-wide significant eQTLs, per sample, than comparable human resources, and reveals sex and age-related expression patterns. Findings include a master regulatory locus that likely plays a role in immune function, and a locus regulating hippocampal long non-coding RNAs (lncRNAs), whose expression correlates with hippocampal volume. This resource will facilitate genetic investigation of quantitative traits, including brain and behavioral phenotypes relevant to neuropsychiatric disorders. PMID:29083405

Buoyancy differences among two deepwater ciscoes from the Great Lakes and their putative ancestor

USGS Publications Warehouse

Krause, A.E.; Eshenroder, R.L.; Begnoche, L.J.

2002-01-01

We analyzed buoyancy in two deepwater ciscoes, Coregonus hoyi and C. kiyi, and in C. artedi, their putative ancestor, and also analyzed how variations in fish weight, water content, and lipid content affected buoyancy. Buoyancy was significantly different among the three species (p < 0.0001). Estimates of percent buoyancy (neutral buoyancy = 0.0%) were: kiyi, 3.8%; hoyi, 4.7%; and artedi, 5.7%. Buoyancy did not change with fish weight alone (p = 0.38). Fish weight was negatively related to water content for all three species (p = 0.037). Lipid content was not significantly different between hoyi and kiyi, but artedi had significantly fewer lipids than hoyi and kiyi (p < 0.10). When artedi was removed from the analysis, fish weight and lipids accounted for 48% of the variation in buoyancy (p = 0.003), fatter hoyi were less dense than leaner hoyi, but fatter and leaner kiyi were no different in density. Our findings provide additional evidence that buoyancy regulation was a speciating mechanism in deepwater ciscoes and that kiyi is more specialized than hoyi for diel-vertical migration in deep water.

Cross-country disparity in agricultural productivity: quantifying the role of modern seed adoption.

PubMed

O'Gorman, Melanie; Pandey, Manish

2010-01-01

Inequality of agricultural labour productivity across the developing world has increased substantially over the past 40 years. This article asks: to what extent did the diffusion of Green Revolution seed varieties contribute to increasing agricultural labour productivity disparity across the developing countries? We find that 22 per cent of cross-country variation in agricultural labour productivity can be attributed to the diffusion of high-yielding seed varieties across countries, and that the impact of such diffusion differed significantly across regions. We discuss the implications of these findings for policy directed at increasing agricultural labour productivity in the developing world.

Circadian pathway genetic variation and cancer risk: evidence from genome-wide association studies.

PubMed

Mocellin, Simone; Tropea, Saveria; Benna, Clara; Rossi, Carlo Riccardo

2018-02-19

Dysfunction of the circadian clock and single polymorphisms of some circadian genes have been linked to cancer susceptibility, although data are scarce and findings inconsistent. We aimed to investigate the association between circadian pathway genetic variation and risk of developing common cancers based on the findings of genome-wide association studies (GWASs). Single nucleotide polymorphisms (SNPs) of 17 circadian genes reported by three GWAS meta-analyses dedicated to breast (Discovery, Biology, and Risk of Inherited Variants in Breast Cancer (DRIVE) Consortium; cases, n = 15,748; controls, n = 18,084), prostate (Elucidating Loci Involved in Prostate Cancer Susceptibility (ELLIPSE) Consortium; cases, n = 14,160; controls, n = 12,724) and lung carcinoma (Transdisciplinary Research In Cancer of the Lung (TRICL) Consortium; cases, n = 12,160; controls, n = 16,838) in patients of European ancestry were utilized to perform pathway analysis by means of the adaptive rank truncated product (ARTP) method. Data were also available for the following subgroups: estrogen receptor negative breast cancer, aggressive prostate cancer, squamous lung carcinoma and lung adenocarcinoma. We found a highly significant statistical association between circadian pathway genetic variation and the risk of breast (pathway P value = 1.9 × 10 -6 ; top gene RORA, gene P value = 0.0003), prostate (pathway P value = 4.1 × 10 -6 ; top gene ARNTL, gene P value = 0.0002) and lung cancer (pathway P value = 6.9 × 10 -7 ; top gene RORA, gene P value = 2.0 × 10 -6 ), as well as all their subgroups. Out of 17 genes investigated, 15 were found to be significantly associated with the risk of cancer: four genes were shared by all three malignancies (ARNTL, CLOCK, RORA and RORB), two by breast and lung cancer (CRY1 and CRY2) and three by prostate and lung cancer (NPAS2, NR1D1 and PER3), whereas four genes were specific for lung cancer (ARNTL2, CSNK1E, NR1D2 and PER2) and two for breast cancer (PER1, RORC). Our findings, based on the largest series ever utilized for ARTP-based gene and pathway analysis, support the hypothesis that circadian pathway genetic variation is involved in cancer predisposition.

Examining for any impact of climate change on the association between seasonality and hospitalization for mania.

PubMed

Parker, Gordon B; Hadzi-Pavlovic, Dusan; Graham, Rebecca K

2017-01-15

Studies have established higher rates of hospitalization for mania in spring and summer and posit various explanatory climatic variables. As the earth's climate is changing, we pursue whether this is reflected in the yearly seasonal variation in hospitalizations for mania. This would be indicated by the presence of secular changes in both the hospitalization seasonal pattern and climatic variables, and associations between both variable sets. Data were obtained for 21,882 individuals hospitalized to psychiatric hospitals in the Australian state of New South Wales (NSW) over a 14-year period (2000-2014) with ICD-diagnosed mania - and with NSW population figures and salient climatic variables collected for the same period. Regression analyses were conducted to examine the predictive value of climate variables on hospital admissions. Data quantified a peak for manic admissions in spring of the southern hemisphere, in the months of October and November. There was a significant linear increase in manic admissions (0.5%/year) over the 14-year time period, with significant variation across years. In terms of climatic variables, there was a significant linear trend over the interval for solar radiation, although the trend indicated a decrease rather than an increase. Seasonal variation in admissions was most closely associated with two climate variables - evaporation in the current month and temperature in the previous month. Hospitalization rates do not necessarily provide an accurate estimate of the onset of manic episodes and findings may be limited to the southern hemisphere, or New South Wales. While overall findings do not support the hypothesis that climate change is leading to a higher seasonal impact for manic hospital admissions in the southern hemisphere, analyses identified two climate/weather variables - evaporation and temperature - that may account for the yearly spring excess. Copyright © 2016 Elsevier B.V. All rights reserved.

ALOX12 polymorphisms are associated with fat mass but not peak bone mineral density in Chinese nuclear families.

PubMed

Xiao, W-J; He, J-W; Zhang, H; Hu, W-W; Gu, J-M; Yue, H; Gao, G; Yu, J-B; Wang, C; Ke, Y-H; Fu, W-Z; Zhang, Z-L

2011-03-01

Arachidonate 12-lipoxygenase (ALOX12) is a member of the lipoxygenase superfamily, which catalyzes the incorporation of molecular oxygen into polyunsaturated fatty acids. The products of ALOX12 reactions serve as endogenous ligands for peroxisome proliferator-activated receptor γ (PPARG). The activation of the PPARG pathway in marrow-derived mesenchymal progenitors stimulates adipogenesis and inhibits osteoblastogenesis. Our objective was to determine whether polymorphisms in the ALOX12 gene were associated with variations in peak bone mineral density (BMD) and obesity phenotypes in young Chinese men. All six tagging single-nucleotide polymorphisms (SNPs) in the ALOX12 gene were genotyped in a total of 1215 subjects from 400 Chinese nuclear families by allele-specific polymerase chain reaction. The BMD at the lumbar spine and hip, total fat mass (TFM) and total lean mass (TLM) were measured using dual-energy X-ray absorptiometry. The pairwise linkage disequilibrium among SNPs was measured, and the haplotype blocks were inferred. Both the individual SNP markers and the haplotypes were tested for an association with the peak BMD, body mass index, TFM, TLM and percentage fat mass (PFM) using the quantitative transmission disequilibrium test (QTDT). Using the QTDT, significant within-family association was found between the rs2073438 polymorphism in the ALOX12 gene and the TFM and PFM (P=0.007 and 0.012, respectively). Haplotype analyses were combined with our individual SNP results and remained significant even after correction for multiple testing. However, we failed to find significant within-family associations between ALOX12 SNPs and the BMD at any bone site in young Chinese men. Our present results suggest that the rs2073438 polymorphism of ALOX12 contributes to the variation of obesity phenotypes in young Chinese men, although we failed to replicate the association with the peak BMD variation in this sample. Further independent studies are needed to confirm our findings.

Does quality control matter? Surface urban heat island intensity variations estimated by satellite-derived land surface temperature products

NASA Astrophysics Data System (ADS)

Lai, Jiameng; Zhan, Wenfeng; Huang, Fan; Quan, Jinling; Hu, Leiqiu; Gao, Lun; Ju, Weimin

2018-05-01

The temporally regular and spatially comprehensive monitoring of surface urban heat islands (SUHIs) have been extremely difficult, until the advent of satellite-based land surface temperature (LST) products. However, these LST products have relatively higher errors compared to in situ measurements. This has resulted in comparatively inaccurate estimations of SUHI indicators and, consequently, may have distorted interpretations of SUHIs. Although reports have shown that LST qualities are important for SUHI interpretations, systematic investigations of the response of SUHI indicators to LST qualities across cities with dissimilar bioclimates are rare. To address this issue, we chose eighty-six major cities across mainland China and analyzed SUHI intensity (SUHII) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) LST data. The LST-based SUHII differences due to inclusion or exclusion of MODIS quality control (QC) flags (i.e., ΔSUHII) were evaluated. Our major findings included, but are not limited to, the following four aspects: (1) SUHIIs can be significantly impacted by MODIS QC flags, and the associated QC-induced ΔSUHIIs generally accounted for 24.3% (29.9%) of the total SUHII value during the day (night); (2) the ΔSUHIIs differed between seasons, with considerable differences between transitional (spring and autumn) and extreme (summer and winter) seasons; (3) significant discrepancies also appeared among cities located in northern and southern regions, with northern cities often possessing higher annual mean ΔSUHIIs. The internal variations of ΔSUHIIs within individual cities also showed high heterogeneity, with ΔSUHII variations that generally exceeded 5.0 K (3.0 K) in northern (southern) cities; (4) ΔSUHIIs were negatively related to SUHIIs and cloud cover percentages (mostly in transitional seasons). No significant relationship was found in the extreme seasons. Our findings highlight the need to be extremely cautious when using LST product-based SUHIIs to interpret SUHIs.

The Heart´s rhythm 'n' blues: Sex differences in circadian variation patterns of vagal activity vary by depressive symptoms in predominantly healthy employees.

PubMed

Jarczok, Marc N; Aguilar-Raab, Corina; Koenig, Julian; Kaess, Michael; Borniger, Jeremy C; Nelson, Randy J; Hall, Martica; Ditzen, Beate; Thayer, Julian F; Fischer, Joachim E

2018-03-15

Successful regulation of emotional states is positively associated to mental health, while difficulties in regulating emotions are negatively associated to overall mental health and in particular associated with anxiety or depression symptoms. A key structure associated to socio-emotional regulatory processes is the central autonomic network. Activity in this structure is associated to vagal activity can be indexed noninvasively and simply by measures of peripheral cardiac autonomic modulations such as heart rate variability. Vagal activity exhibits a circadian variation pattern, with a maximum during nighttime. Depression is known to affect chronobiology. Also, depressive symptoms are known to be associated with decreased resting state vagal activity, but studies investigating the association between circadian variation pattern of vagal activity and depressive symptoms are scarce. We aim to examine these patterns in association to symptom severity of depression using chronobiologic methods. Data from the Manheim Industrial Cohort Studies (MICS) were used. A total of 3,030 predominantly healthy working adults underwent, among others, ambulatory 24-h hear rate-recordings, detailed health examination and online questionnaires and were available for this analysis. The root mean sum of successive differences (RMSSD) was used as an indicator of vagally mediated heart rate variability. Three individual-level cosine function parameters (MESOR, amplitude, acrophase) were estimated to quantify circadian variation pattern. Multivariate linear regression models including important covariates such as age, sex, and lifestyle factors as well as an interaction effect of sex with depressive symptoms were used to estimate the association of circadian variation pattern of vagal activity with depressive symptoms simultaneously. The analysis sample consisted of 20.2% females and an average age 41 with standard deviation of 11 years. Nonparametric bivariate analysis revealed significant MESOR and amplitude differences between the 90 th percentile split, but not on acrophase. Multivariate linear regression models estimated depressive symptoms to be negatively associated with the 24h mean (MESOR) and oscillation amplitude in men but positively associated in women. This pattern of findings indicates a blunted day-night rhythm of vagal activity in men with greater depressive symptoms as well as a moderation effect of sex in the association of CVP and depressive symptoms. This is the first study investigating circadian variation pattern by mild depressive symptoms in a large, rather healthy occupational sample. Depressive symptoms were associated with decreased circadian variation pattern of vagal activity in men but with increased circadian variation pattern in women. The possible underlying mechanism(s) are discussed using the neurovisceral integration model. These findings may have implications for the knowledge on etiology, diagnosis, course, and treatment of depressive symptoms and thus may be of significant public health relevance.

Elevated Proportions of Deleterious Genetic Variation in Domestic Animals and Plants

PubMed Central

Rubin, Carl-Johan; Carneiro, Miguel; Axelsson, Erik; Andersson, Leif

2018-01-01

Abstract A fraction of genetic variants segregating in any population are deleterious, which negatively impacts individual fitness. The domestication of animals and plants is associated with population bottlenecks and artificial selection, which are predicted to increase the proportion of deleterious variants. However, the extent to which this is a general feature of domestic species is unclear. Here, we examine the effects of domestication on the prevalence of deleterious variation using pooled whole-genome resequencing data from five domestic animal species (dog, pig, rabbit, chicken, and silkworm) and two domestic plant species (rice and soybean) compared with their wild ancestors. We find significantly reduced genetic variation and increased proportion of nonsynonymous amino acid changes in all but one of the domestic species. These differences are observable across a range of allele frequencies, both common and rare. We find proportionally more single nucleotide polymorphisms in highly conserved elements in domestic species and a tendency for domestic species to harbor a higher proportion of changes classified as damaging. Our findings most likely reflect an increased incidence of deleterious variants in domestic species, which is most likely attributable to population bottlenecks that lead to a reduction in the efficacy of selection. An exception to this pattern is displayed by European domestic pigs, which do not show traces of a strong population bottleneck and probably continued to exchange genes with wild boar populations after domestication. The results presented here indicate that an elevated proportion of deleterious variants is a common, but not ubiquitous, feature of domestic species. PMID:29325102

NEBULAR AND STELLAR DUST EXTINCTION ACROSS THE DISK OF EMISSION-LINE GALAXIES ON KILOPARSEC SCALES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hemmati, Shoubaneh; Mobasher, Bahram; Darvish, Behnam

We investigate the resolved kiloparsec-scale stellar and nebular dust distribution in eight star-forming galaxies at z ∼ 0.4 in the Great Observatories Origins Deep Survey fields. This is to get a better understanding of the effect of dust attenuation on measurements of physical properties and its variation with redshift. Constructing the observed spectral energy distributions (SEDs) per pixel, based on seven bands of photometric data from Hubble Space Telescope/Advanced Camera for Surveys and WFC3, we performed pixel-by-pixel SED fits to population synthesis models and estimated the small-scale distribution of stellar dust extinction. We use Hα/Hβ nebular emission line ratios from Keck/DEIMOS high-resolutionmore » spectra at each spatial resolution element to measure the amount of attenuation faced by ionized gas at different radii from the centers of galaxies. We find a good agreement between the integrated and median of resolved color excess measurements in our galaxies. The ratio of integrated nebular to stellar dust extinction is always greater than unity, but does not show any trend with stellar mass or star formation rate (SFR). We find that inclination plays an important role in the variation of the nebular to stellar excess ratio. The stellar color excess profiles are found to have higher values at the center compared to outer parts of the disk. However, for lower mass galaxies, a similar trend is not found for the nebular color excess. We find that the nebular color excess increases with stellar mass surface density. This explains the absence of radial trend in the nebular color excess in lower mass galaxies which lack a large radial variation of stellar mass surface density. Using standard conversions of SFR surface density to gas mass surface density, and the relation between dust mass surface density and color excess, we find no significant variation in the dust-to-gas ratio in regions with high gas mass surface densities over the scales probed in this study.« less

Temporal shifts and temperature sensitivity of avian spring migratory phenology: a phylogenetic meta-analysis.

PubMed

Usui, Takuji; Butchart, Stuart H M; Phillimore, Albert B

2017-03-01

There are wide reports of advances in the timing of spring migration of birds over time and in relation to rising temperatures, though phenological responses vary substantially within and among species. An understanding of the ecological, life-history and geographic variables that predict this intra- and interspecific variation can guide our projections of how populations and species are likely to respond to future climate change. Here, we conduct phylogenetic meta-analyses addressing slope estimates of the timing of avian spring migration regressed on (i) year and (ii) temperature, representing a total of 413 species across five continents. We take into account slope estimation error and examine phylogenetic, ecological and geographic predictors of intra- and interspecific variation. We confirm earlier findings that on average birds have significantly advanced their spring migration time by 2·1 days per decade and 1·2 days °C -1 . We find that over time and in response to warmer spring conditions, short-distance migrants have advanced spring migratory phenology by more than long-distance migrants. We also find that larger bodied species show greater advance over time compared to smaller bodied species. Our results did not reveal any evidence that interspecific variation in migration response is predictable on the basis of species' habitat or diet. We detected a substantial phylogenetic signal in migration time in response to both year and temperature, suggesting that some of the shifts in migratory phenological response to climate are predictable on the basis of phylogeny. However, we estimate high levels of species and spatial variance relative to phylogenetic variance, which is consistent with plasticity in response to climate evolving fairly rapidly and being more influenced by adaptation to current local climate than by common descent. On average, avian spring migration times have advanced over time and as spring has become warmer. While we are able to identify predictors that explain some of the true among-species variation in response, substantial intra- and interspecific variation in migratory response remains to be explained. © 2016 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Quantifying Neonatal Sucking Performance: Promise of New Methods

PubMed Central

Capilouto, Gilson J.; Cunningham, Tommy J.; Mullineaux, David R.; Tamilia, Eleonora; Papadelis, Christos; Giannone, Peter J.

2017-01-01

Neonatal feeding has been traditionally understudied so guidelines and evidence-based support for common feeding practices are limited. A major contributing factor to the paucity of evidence-based practice in this area has been the lack of simple-to-use, low-cost tools for monitoring sucking performance. We describe new methods for quantifying neonatal sucking performance that hold significant clinical and research promise. We present early results from an ongoing study investigating neonatal sucking as a marker of risk for adverse neurodevelopmental outcomes. We include quantitative measures of sucking performance to better understand how movement variability evolves during skill acquisition. Results showed the coefficient of variation of suck duration was significantly different between preterm neonates at high risk for developmental concerns (HRPT) and preterm neonates at low risk for developmental concerns (LRPT). For HRPT, results indicated the coefficient of variation of suck smoothness increased from initial feeding to discharge and remained significantly greater than healthy full-term newborns (FT) at discharge. There was no significant difference in our measures between FT and LRPT at discharge. Our findings highlight the need to include neonatal sucking assessment as part of routine clinical care in order to capture the relative risk of adverse neurodevelopmental outcomes at discharge. PMID:28324904

Regional and temporal differences in gene expression of LH(BETA)T(AG) retinoblastoma tumors.

PubMed

Houston, Samuel K; Pina, Yolanda; Clarke, Jennifer; Koru-Sengul, Tulay; Scott, William K; Nathanson, Lubov; Schefler, Amy C; Murray, Timothy G

2011-07-23

The purpose of this study was to evaluate by microarray the hypothesis that LH(BETA)T(AG) retinoblastoma tumors exhibit regional and temporal variations in gene expression. LH(BETA)T(AG) mice aged 12, 16, and 20 weeks were euthanatized (n = 9). Specimens were taken from five tumor areas (apex, anterior lateral, center, base, and posterior lateral). Samples were hybridized to gene microarrays. The data were preprocessed and analyzed, and genes with a P < 0.01, according to the ANOVA models, and a log(2)-fold change >2.5 were considered to be differentially expressed. Differentially expressed genes were analyzed for overlap with known networks by using pathway analysis tools. There were significant temporal (P < 10(-8)) and regional differences in gene expression for LH(BETA)T(AG) retinoblastoma tumors. At P < 0.01 and log(2)-fold change >2.5, there were significant changes in gene expression of 190 genes apically, 84 genes anterolaterally, 126 genes posteriorly, 56 genes centrally, and 134 genes at the base. Differentially expressed genes overlapped with known networks, with significant involvement in regulation of cellular proliferation and growth, response to oxygen levels and hypoxia, regulation of cellular processes, cellular signaling cascades, and angiogenesis. There are significant temporal and regional variations in the LH(BETA)T(AG) retinoblastoma model. Differentially expressed genes overlap with key pathways that may play pivotal roles in murine retinoblastoma development. These findings suggest the mechanisms involved in tumor growth and progression in murine retinoblastoma tumors and identify pathways for analysis at a functional level, to determine significance in human retinoblastoma. Microarray analysis of LH(BETA)T(AG) retinal tumors showed significant regional and temporal variations in gene expression, including dysregulation of genes involved in hypoxic responses and angiogenesis.

Genetics of schizophrenia and smoking: an approach to studying their comorbidity based on epidemiological findings

PubMed Central

de Leon, Jose; Diaz, Francisco J.

2012-01-01

The association between schizophrenia and tobacco smoking has been described in more than 1,000 articles, many with inadequate methodology. The studies on this association can focus on: (1) current smoking, ever smoking or smoking cessation; (2) non-psychiatric controls or controls with severe mental illness (e.g., bipolar disorder); and (3) higher smoking frequency or greater usage in smokers. The association with the most potential for genetic studies is that between ever daily smoking and schizophrenia; it may reflect a shared genetic vulnerability. To reduce the number of false-positive genes, we propose a three-stage approach derived from epidemiological knowledge. In the first stage, only genetic variations associated with ever daily smoking that are simultaneously significant within the non-psychiatric controls, the bipolar disorder controls and the schizophrenia cases will be selected. Only those genetic variations that are simultaneously significant in the three hypothesis tests will be tested in the second stage, where the prevalence of the genes must be significantly higher in schizophrenia than in bipolar disorder, and significantly higher in bipolar disorder than in controls. The genes simultaneously significant in the second stage will be included in a third stage where the gene variations must be significantly more frequent in schizophrenia patients who did not start smoking daily until their 20s (late start) versus those who had an early start. Any genetic approach to psychiatric disorders may fail if attention is not given to comorbidity and epidemiological studies that suggest which comorbidities are likely to be explained by genetics and which are not. Our approach, which examines the results of epidemiological studies on comorbidities and then looks for genes that simultaneously satisfy epidemiologically suggested sets of hypotheses, may also apply to the study of other major illnesses. PMID:22190153

Quantification of the tissue-culture induced variation in barley (Hordeum vulgare L.)

PubMed Central

Bednarek, Piotr T; Orłowska, Renata; Koebner, Robert MD; Zimny, Janusz

2007-01-01

Background When plant tissue is passaged through in vitro culture, many regenerated plants appear to be no longer clonal copies of their donor genotype. Among the factors that affect this so-called tissue culture induced variation are explant genotype, explant tissue origin, medium composition, and the length of time in culture. Variation is understood to be generated via a combination of genetic and/or epigenetic changes. A lack of any phenotypic variation between regenerants does not necessarily imply a concomitant lack of genetic (or epigenetic) change, and it is therefore of interest to assay the outcomes of tissue culture at the genotypic level. Results A variant of methylation sensitive AFLP, based on the isoschizomeric combinations Acc65I/MseI and KpnI/MseI was applied to analyze, at both the sequence and methylation levels, the outcomes of regeneration from tissue culture in barley. Both sequence mutation and alteration in methylation pattern were detected. Two sets of regenerants from each of five DH donor lines were compared. One set was derived via androgenesis, and the other via somatic embryogenesis, developed from immature embryos. These comparisons delivered a quantitative assessment of the various types of somaclonal variation induced. The average level of variation was 6%, of which almost 1.7% could be accounted for by nucleotide mutation, and the remainder by changes in methylation state. The nucleotide mutation rates and the rate of epimutations were substantially similar between the andro- and embryo-derived sets of regenerants across all the donors. Conclusion We have developed an AFLP based approach that is capable of describing the qualitative and quantitative characteristics of the tissue culture-induced variation. We believe that this approach will find particular value in the study of patterns of inheritance of somaclonal variation, since non-heritable variation is of little interest for the improvement of plant species which are sexually propagated. Of significant biological interest is the conclusion that the mode of regeneration has no significant effect on the balance between sequence and methylation state change induced by the tissue culture process. PMID:17335560

Diagnostic Challenges in Retinitis Pigmentosa: Genotypic Multiplicity and Phenotypic Variability

PubMed Central

Chang, Susie; Vaccarella, Leah; Olatunji, Sunday; Cebulla, Colleen; Christoforidis, John

2011-01-01

Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal disorders. Diagnosis can be challenging as more than 40 genes are known to cause non-syndromic RP and phenotypic expression can differ significantly resulting in variations in disease severity, age of onset, rate of progression, and clinical findings. We describe the clinical manifestations of RP, the more commonly known causative gene mutations, and the genotypic-phenotypic correlation of RP. PMID:22131872

A Comprehensive Analysis of Common Genetic Variation Around Six Candidate Loci for Intrahepatic Cholestasis of Pregnancy

PubMed Central

Dixon, Peter H; Wadsworth, Christopher A; Chambers, Jennifer; Donnelly, Jennifer; Cooley, Sharon; Buckley, Rebecca; Mannino, Ramona; Jarvis, Sheba; Syngelaki, Argyro; Geenes, Victoria; Paul, Priyadarshini; Sothinathan, Meera; Kubitz, Ralf; Lammert, Frank; Tribe, Rachel M; Ch'ng, Chin Lye; Marschall, Hanns-Ulrich; Glantz, Anna; Khan, Shahid A; Nicolaides, Kypros; Whittaker, John; Geary, Michael; Williamson, Catherine

2014-01-01

OBJECTIVES: Intrahepatic cholestasis of pregnancy (ICP) has a complex etiology with a significant genetic component. Heterozygous mutations of canalicular transporters occur in a subset of ICP cases and a population susceptibility allele (p.444A) has been identified in ABCB11. We sought to expand our knowledge of the detailed genetic contribution to ICP by investigation of common variation around candidate loci with biological plausibility for a role in ICP (ABCB4, ABCB11, ABCC2, ATP8B1, NR1H4, and FGF19). METHODS: ICP patients (n=563) of white western European origin and controls (n=642) were analyzed in a case–control design. Single-nucleotide polymorphism (SNP) markers (n=83) were selected from the HapMap data set (Tagger, Haploview 4.1 (build 22)). Genotyping was performed by allelic discrimination assay on a robotic platform. Following quality control, SNP data were analyzed by Armitage's trend test. RESULTS: Cochran–Armitage trend testing identified six SNPs in ABCB11 together with six SNPs in ABCB4 that showed significant evidence of association. The minimum Bonferroni corrected P value for trend testing ABCB11 was 5.81×10−4 (rs3815676) and for ABCB4 it was 4.6×10−7(rs2109505). Conditional analysis of the two clusters of association signals suggested a single signal in ABCB4 but evidence for two independent signals in ABCB11. To confirm these findings, a second study was performed in a further 227 cases, which confirmed and strengthened the original findings. CONCLUSIONS: Our analysis of a large cohort of ICP cases has identified a key role for common variation around the ABCB4 and ABCB11 loci, identified the core associations, and expanded our knowledge of ICP susceptibility. PMID:24366234

Determinants of variations in initial treatment strategies for stable ischemic heart disease

PubMed Central

Bennell, Maria C.; Qiu, Feng; Kingsbury, Kori J.; Austin, Peter C.; Wijeysundera, Harindra C.

2015-01-01

Background: The ratio of revascularization to medical therapy (referred to herein as the revascularization ratio) for the initial treatment of stable ischemic heart disease varies considerably across hospitals. We conducted a comprehensive study to identify patient, physician and hospital factors associated with variations in the revascularization ratio across 18 cardiac centres in the province of Ontario. We also explored whether clinical outcomes differed between hospitals with high, medium and low ratios. Methods: We identified all patients in Ontario who had stable ischemic heart disease documented by index angiography performed between Oct. 1, 2008, and Sept. 30, 2011, at any of the 18 cardiac centres in the province. We classified patients by initial treatment strategy (medical therapy or revascularization). Hospitals were classified into equal tertiles based on their revascularization ratio. The primary outcome was all-cause mortality. Patient follow-up was until Dec. 31, 2012. Hierarchical logistic regression models identified predictors of revascularization. Multivariable Cox proportional hazards models, with a time-varying covariate for actual treatment received, were used to evaluate the impact of the revascularization ratio on clinical outcomes. Results: Variation in revascularization ratios was twofold across the hospitals. Patient factors accounted for 67.4% of the variation in revascularization ratios. Physician and hospital factors were not significantly associated with the variation. Significant patient-level predictors of revascularization were history of smoking, multivessel disease, high-risk findings on noninvasive stress testing and more severe symptoms of angina (v. no symptoms). Treatment at hospitals with a high revascularization ratio was associated with increased mortality compared with treatment at hospitals with a low ratio (hazard ratio 1.12, 95% confidence interval 1.03–1.21). Interpretation: Most of the variation in revascularization ratios across hospitals was warranted, in that it was driven by patient factors. Nonetheless, the variation was associated with potentially important differences in mortality. PMID:25991840

Spatial Distribution and Semiannual Variation of Cold-Dense Plasma Sheet

NASA Astrophysics Data System (ADS)

Bai, Shichen; Shi, Quanqi; Tian, Anmin; Nowada, Motoharu; Degeling, Alexander W.; Zhou, Xu-Zhi; Zong, Qiu-Gang; Rae, I. Jonathan; Fu, Suiyan; Zhang, Hui; Pu, Zuyin; Fazakerly, Andrew N.

2018-01-01

The cold-dense plasma sheet (CDPS) plays an important role in the entry process of the solar wind plasma into the magnetosphere. Investigating the seasonal variation of CDPS occurrences will help us better understand the long-term variation of plasma exchange between the solar wind and magnetosphere, but any seasonal variation of CDPS occurrences has not yet been reported in the literature. In this paper, we investigate the seasonal variation of the occurrence rate of CDPS using Geotail data from 1996 to 2015 and find a semiannual variation of the CDPS occurrences. Given the higher probability of solar wind entry under stronger northward interplanetary magnetic field (IMF) conditions, 20 years of IMF data (1996-2015) are used to investigate the seasonal variation of IMF Bz under northward IMF conditions. We find a semiannual variation of IMF Bz, which is consistent with the Russell-McPherron (R-M) effect. We therefore suggest that the semiannual variation of CDPS may be related to the R-M effect.

Examining variation in treatment costs: a cost function for outpatient methadone treatment programs.

PubMed

Dunlap, Laura J; Zarkin, Gary A; Cowell, Alexander J

2008-06-01

To estimate a hybrid cost function of the relationship between total annual cost for outpatient methadone treatment and output (annual patient days and selected services), input prices (wages and building space costs), and selected program and patient case-mix characteristics. Data are from a multistate study of 159 methadone treatment programs that participated in the Center for Substance Abuse Treatment's Evaluation of the Methadone/LAAM Treatment Program Accreditation Project between 1998 and 2000. Using least squares regression for weighted data, we estimate the relationship between total annual costs and selected output measures, wages, building space costs, and selected program and patient case-mix characteristics. Findings indicate that total annual cost is positively associated with program's annual patient days, with a 10 percent increase in patient days associated with an 8.2 percent increase in total cost. Total annual cost also increases with counselor wages (p<.01), but no significant association is found for nurse wages or monthly building costs. Surprisingly, program characteristics and patient case mix variables do not appear to explain variations in methadone treatment costs. Similar results are found for a model with services as outputs. This study provides important new insights into the determinants of methadone treatment costs. Our findings concur with economic theory in that total annual cost is positively related to counselor wages. However, among our factor inputs, counselor wages are the only significant driver of these costs. Furthermore, our findings suggest that methadone programs may realize economies of scale; however, other important factors, such as patient access, should be considered.

Crustal uplift in the south central Alaska subduction zone: New analysis and interpretation of tide gauge observations

NASA Astrophysics Data System (ADS)

Cohen, Steven C.; Freymueller, Jeffrey T.

2001-06-01

We have examined tide gauge measurements of apparent sea level height in south central Alaska to determine the history of crustal uplift subsequent to the 1964 Prince William Sound earthquake. There are spatial and temporal variations in the uplift rate since the 1994 earthquake that depend on the location of the tide gauge relative to the coseismic rupture features. At Seward, on the eastern side of the Kenai Peninsula, we find slow uplift that is consistent with elastic strain accumulation at the locked North American-Pacific Plate boundary. Conversely, at Seldovia and Nikiski, on the western side of the Kenai Peninsula, we find persistent rapid uplift of ˜10 mm yr-1 that may be longterm transient response to the earthquake but that cannot be sustained over the entire several hundred year recurrence interval for a great earthquake. Farther to the southwest, at Kodiak, the rate of uplift is several millimeters per year but has slowed significantly over the past three and a half decades. To the east of the Kenai Peninsula we find subsidence at Cordova and an uncertain behavior at Valdez. At Cordova, and to a lesser extent Valdez, there is a mathematically significant time dependence, although the evidence for the time dependence is less compelling than at Kodiak. At Anchorage, there is little evidence of vertical motion since the earthquake. The along-strike spatial variability in the relaxation time of the rates of vertical motion since the 1964 earthquake may be related to variations in the updip coseismic slip during the megathrust event.

A wide extent of inter-strain diversity in virulent and vaccine strains of alphaherpesviruses.

PubMed

Szpara, Moriah L; Tafuri, Yolanda R; Parsons, Lance; Shamim, S Rafi; Verstrepen, Kevin J; Legendre, Matthieu; Enquist, L W

2011-10-01

Alphaherpesviruses are widespread in the human population, and include herpes simplex virus 1 (HSV-1) and 2, and varicella zoster virus (VZV). These viral pathogens cause epithelial lesions, and then infect the nervous system to cause lifelong latency, reactivation, and spread. A related veterinary herpesvirus, pseudorabies (PRV), causes similar disease in livestock that result in significant economic losses. Vaccines developed for VZV and PRV serve as useful models for the development of an HSV-1 vaccine. We present full genome sequence comparisons of the PRV vaccine strain Bartha, and two virulent PRV isolates, Kaplan and Becker. These genome sequences were determined by high-throughput sequencing and assembly, and present new insights into the attenuation of a mammalian alphaherpesvirus vaccine strain. We find many previously unknown coding differences between PRV Bartha and the virulent strains, including changes to the fusion proteins gH and gB, and over forty other viral proteins. Inter-strain variation in PRV protein sequences is much closer to levels previously observed for HSV-1 than for the highly stable VZV proteome. Almost 20% of the PRV genome contains tandem short sequence repeats (SSRs), a class of nucleic acids motifs whose length-variation has been associated with changes in DNA binding site efficiency, transcriptional regulation, and protein interactions. We find SSRs throughout the herpesvirus family, and provide the first global characterization of SSRs in viruses, both within and between strains. We find SSR length variation between different isolates of PRV and HSV-1, which may provide a new mechanism for phenotypic variation between strains. Finally, we detected a small number of polymorphic bases within each plaque-purified PRV strain, and we characterize the effect of passage and plaque-purification on these polymorphisms. These data add to growing evidence that even plaque-purified stocks of stable DNA viruses exhibit limited sequence heterogeneity, which likely seeds future strain evolution.

The brown anole dewlap revisited: do predation pressure, sexual selection, and species recognition shape among-population signal diversity?

PubMed Central

Van Damme, Raoul

2018-01-01

Animal signalling structures are amongst the most variable characteristics, as they are subjected to a diversity of selection pressures. A well-known example of a diverse signalling system in the animal kingdom is the dewlap of Anolis lizards. Dewlap characteristics can vary remarkably among and within species, and also between sexes. Although a considerable amount of studies have attempted to disentangle the functional significance of the staggering dewlap diversity in Anolis, the underlying evolutionary processes remain elusive. In this study, we focus on the contribution of biotic selective pressures in shaping geographic variation in dewlap design (size, colour, and pattern) and dewlap display behaviour at the intraspecific level. Notably, we have tried to replicate and extend previously reported results hereof in both sexes of the brown anole lizard (Anolis sagrei). To do this, we assembled a dataset consisting of 17 A. sagrei heterogeneous island populations from the Caribbean and specifically tested whether predation pressure, sexual selection, or species recognition could explain interpopulational variation in an array of dewlap characteristics. Our findings show that in neither males nor females estimates of predation pressure (island size, tail break frequency, model attack rate, presence of predatory Leiocephalus lizards) or sexual selection (sexual size dimorphism) could explain variation in dewlap design. We did find that A. sagrei males from larger islands showed higher dewlap display intensities than males from smaller islands, but the direct connection with predation pressure remains ambiguous and demands further investigation. Last, we could show indirect support for species recognition only in males, as they are more likely to have a ‘spotted’ dewlap pattern when co-occurring with a higher number of syntopic Anolis species. In conclusion, we found overall limited support for the idea that the extensive interpopulational variability in dewlap design and use in A. sagrei is mediated by variation in their biotic environment. We propose a variety of conceptual and methodological explanations for this unexpected finding. PMID:29761044

Ultrasonographic variations are present in the distal sesamoidean impar ligament of clinically sound horses.

PubMed

MacDonald, Jessica Lauren; Richter, Ruth-Anne; Wimer, Christine L

2018-05-11

Ultrasonography is an established diagnostic test for evaluating horses with foot pain due to suspected podotrochlear apparatus pathology. However, variations from the previously reported normal appearance of the distal sesamoidean impar ligament have not always coincided with lameness. The objective of this prospective, cross-sectional, descriptive study was to characterize variations in the ultrasonographic appearance of the distal sesamoidean impar ligament in sound horses using the transcuneal approach. Transcuneal ultrasonography of the distal sesamoidean impar ligament was performed on sound horses, and images were evaluated for fiber pattern, echogenicity, and thickness. Varying echogenicities of the distal sesamoidean impar ligament compared to the deep digital flexor tendon were found. Hypoechogenic or hyperechogenic focal areas were noted in the mid-body of the distal sesamoidean impar ligament or at its attachment to the navicular bone or the distal phalanx. In some of the sound horses, an anechoic linear area between the deep digital flexor tendon and distal sesamoidean impar ligament was observed as well as multifocal areas of hyperechogenicity or hypoechogenicity, irregular fiber pattern, and measurable thickening of the distal sesamoidean impar ligament. Several findings were bilaterally symmetrical, and no finding was always bilaterally symmetrical each time it was noted. This study supports transcuneal ultrasonography as an ancillary diagnostic tool for evaluating the equine distal sesamoidean impar ligament, describes sonographic variations in clinically sound horses, and suggests that the clinical significance of a lesion may not be determined by comparison of the distal sesamoidean impar ligament in the contralateral limb. © 2018 American College of Veterinary Radiology.

Spectral models for early time SN 2011fe observations

DOE PAGES

Baron, E.; Hoeflich, P.; Friesen, Brian; ...

2015-10-13

We use observed UV through near-IR spectra to examine whether SN 2011fe can be understood in the framework of Branch-normal Type Ia supernovae (SNe Ia) and to examine its individual peculiarities. As a benchmark, we use a delayed-detonationmodel with a progenitormetallicity of Z ⊙/20. We study the sensitivity of features to variations in progenitor metallicity, the outer density profile, and the distribution of radioactive nickel. The effect of metallicity variations in the progenitor have a relatively small effect on the synthetic spectra. We also find that the abundance stratification of SN 2011fe resembles closely that of a delayed-detonation model withmore » a transition density that has been fit to other Branch-normal SNe Ia. At early times, the model photosphere is formed in material with velocities that are too high, indicating that the photosphere recedes too slowly or that SN 2011fe has a lower specific energy in the outer ≈0.1 M ⊙ than does the model. We discuss several explanations for the discrepancies. Lastly, we examine variations in both the spectral energy distribution and in the colours due to variations in the progenitor metallicity, which suggests that colours are only weak indicators for the progenitor metallicity, in the particular explosion model that we have studied. Here we do find that the flux in the U band is significantly higher at maximum light in the solar metallicity model than in the lower metallicity model and the lower metallicity model much better matches the observed spectrum.« less

Is Customization in Antidepressant Prescribing Associated with Acute-Phase Treatment Adherence?

PubMed

Merrick, Elizabeth L; Hodgkin, Dominic; Panas, Lee; Soumerai, Stephen B; Ritter, Grant

2012-03-01

OBJECTIVES: The objective was to explore whether prescribing variation is associated with duration of antidepressant use during the acute phase of treatment. Improving quality of care and increasing the extent to which treatment is patient-centered and customized are interrelated goals. Prescribing variation may be considered a marker of customization, and could be associated with better antidepressant treatment adherence. METHODS: A cross-sectional secondary data analysis examining the association between providers' antidepressant prescribing variation and patient continuity of antidepressant treatment. The data source was two states' Medicaid claims for dual-eligible Medicaid/Medicare patients. The sample included 383 patients with new episodes of antidepressant treatment, representing 70 providers with at least four patients in the sample. We tested two alternate measures of prescribing concentration: 1) share of prescriber's initial antidepressant prescribing accounted for by the two most common regimens, and 2) Herfindahl index. The HEDIS performance measure of effective acute-phase treatment (at least 84 out of 114 days with antidepressant) was the dependent variable. KEY FINDINGS: In multivariate analyses, the concentration measure based on the top two regimens was significant and inversely related to duration adequacy (p <.05). The Herfindahl index measure showed a trend towards a similar inverse relationship (p<.10). CONCLUSIONS: The findings provide some support for the hypothesized relationship between prescribing variation and adequate antidepressant treatment duration during the acute phase of treatment. Future work with more detailed, clinical longitudinal data could extend this inquiry to better understand the causal mechanisms using a more direct measure of customized care.

Is Customization in Antidepressant Prescribing Associated with Acute-Phase Treatment Adherence?

PubMed Central

Merrick, Elizabeth L.; Hodgkin, Dominic; Panas, Lee; Soumerai, Stephen B.; Ritter, Grant

2012-01-01

Objectives The objective was to explore whether prescribing variation is associated with duration of antidepressant use during the acute phase of treatment. Improving quality of care and increasing the extent to which treatment is patient-centered and customized are interrelated goals. Prescribing variation may be considered a marker of customization, and could be associated with better antidepressant treatment adherence. Methods A cross-sectional secondary data analysis examining the association between providers' antidepressant prescribing variation and patient continuity of antidepressant treatment. The data source was two states' Medicaid claims for dual-eligible Medicaid/Medicare patients. The sample included 383 patients with new episodes of antidepressant treatment, representing 70 providers with at least four patients in the sample. We tested two alternate measures of prescribing concentration: 1) share of prescriber's initial antidepressant prescribing accounted for by the two most common regimens, and 2) Herfindahl index. The HEDIS performance measure of effective acute-phase treatment (at least 84 out of 114 days with antidepressant) was the dependent variable. Key Findings In multivariate analyses, the concentration measure based on the top two regimens was significant and inversely related to duration adequacy (p <.05). The Herfindahl index measure showed a trend towards a similar inverse relationship (p<.10). Conclusions The findings provide some support for the hypothesized relationship between prescribing variation and adequate antidepressant treatment duration during the acute phase of treatment. Future work with more detailed, clinical longitudinal data could extend this inquiry to better understand the causal mechanisms using a more direct measure of customized care. PMID:22707982

Running vacuum in the Universe and the time variation of the fundamental constants of Nature

NASA Astrophysics Data System (ADS)

Fritzsch, Harald; Solà, Joan; Nunes, Rafael C.

2017-03-01

We compute the time variation of the fundamental constants (such as the ratio of the proton mass to the electron mass, the strong coupling constant, the fine-structure constant and Newton's constant) within the context of the so-called running vacuum models (RVMs) of the cosmic evolution. Recently, compelling evidence has been provided that these models are able to fit the main cosmological data (SNIa+BAO+H(z)+LSS+BBN+CMB) significantly better than the concordance Λ CDM model. Specifically, the vacuum parameters of the RVM (i.e. those responsible for the dynamics of the vacuum energy) prove to be nonzero at a confidence level ≳ 3σ . Here we use such remarkable status of the RVMs to make definite predictions on the cosmic time variation of the fundamental constants. It turns out that the predicted variations are close to the present observational limits. Furthermore, we find that the time evolution of the dark matter particle masses should be crucially involved in the total mass variation of our Universe. A positive measurement of this kind of effects could be interpreted as strong support to the "micro-macro connection" (viz. the dynamical feedback between the evolution of the cosmological parameters and the time variation of the fundamental constants of the microscopic world), previously proposed by two of us (HF and JS).

Does stronger pollen competition improve offspring fitness when pollen load does not vary?

PubMed

Pélabon, Christophe; Hennet, Lauriane; Bolstad, Geir H; Albertsen, Elena; Opedal, Øystein H; Ekrem, Runa K; Armbruster, W Scott

2016-03-01

Competition among pollen grains from a single donor is expected to increase the quality of the offspring produced because of the recessive deleterious alleles expressed during pollen-tube growth. However, evidence for such an effect is inconclusive; a large number of studies suffer from confounding variation in pollen competition with variation in pollen load. In this study, we tested the effect of pollen competition on offspring performance independently of pollen-load variation. We compared seed mass and early seedling performance in Dalechampia scandens (Euphorbiaceae) between crosses in which variation in pollen competition was achieved, without variation in pollen load, by manipulating the dispersion of pollen grains on the stigmas. Despite a large sample size (211 crosses on 20 maternal plants), we failed to find an effect of pollen competition on seed characteristics or early seedling performance. Paternal effects were always limited, and pollen competition never reduced the within-father (residual) variance. These results suggest that limited within-donor variation in genetic quality of pollen grains reduces the potential benefits of pollen competition in the study population. The lack of paternal effects on early sporophyte performance further suggests that benefits of pollen competition among pollen from multiple donors should be limited as well, and it raises questions about the significance of pollen competition as a mechanism of sexual selection. © 2016 Botanical Society of America.

Ultraviolet continuum variability and visual flickering in the peculiar object MWC 560

NASA Technical Reports Server (NTRS)

Michalitsianos, A. G.; Perez, M.; Shore, S. N.; Maran, S. P.; Karovska, M.; Sonneborn, G.; Webb, J. R.; Barnes, Thomas G., III; Frueh, Marian L.; Oliversen, R. J.

1993-01-01

High-speed U-band photometry of the peculiar emission object MWC 560 obtained with the ground-based instrumentation, and V-band photometry obtained with the International Ultraviolet Explorer-Fine Error Sensor indicates irregular brightness variations are quasi-periodic. Multiple peaks of relative brightness power indicate statistically significant quasi periods existing in a range of 3-35 minutes, that are superposed on slower hourly varying components. We present a preliminary model that explains the minute and hourly time-scale variations in MWC 560 in terms of a velocity-shear instability that arises because a white dwarf magnetosphere impinges on an accretion disk. We also find evidence for Fe II multiplet pseudocontinuum absorption opacity in far-UV spectra of CH Cygni which is also present in MWC 560. Both CH Cyg and MWC 560 may be in an evolutionary stage that is characterized by strong UV continuum opacity which changes significantly during outburst, occurring before they permanently enter the symbiotic nebular emission phase.

Intelligence in Williams Syndrome Is Related to STX1A, Which Encodes a Component of the Presynaptic SNARE Complex

PubMed Central

Gao, Michael C.; Bellugi, Ursula; Dai, Li; Mills, Debra L.; Sobel, Eric M.; Lange, Kenneth; Korenberg, Julie R.

2010-01-01

Although genetics is the most significant known determinant of human intelligence, specific gene contributions remain largely unknown. To accelerate understanding in this area, we have taken a new approach by studying the relationship between quantitative gene expression and intelligence in a cohort of 65 patients with Williams Syndrome (WS), a neurodevelopmental disorder caused by a 1.5 Mb deletion on chromosome 7q11.23. We find that variation in the transcript levels of the brain gene STX1A correlates significantly with intelligence in WS patients measured by principal component analysis (PCA) of standardized WAIS-R subtests, r  = 0.40 (Pearson correlation, Bonferroni corrected p-value  = 0.007), accounting for 15.6% of the cognitive variation. These results suggest that syntaxin 1A, a neuronal regulator of presynaptic vesicle release, may play a role in WS and be a component of the cellular pathway determining human intelligence. PMID:20422020

Age and Race Differences in the Trajectories of Self-Esteem

PubMed Central

Shaw, Benjamin A.; Liang, Jersey; Krause, Neal

2010-01-01

The purpose of this research was to assess age- and race-based variation in within-persons changes in self-esteem over a 16-year period. We used hierarchical linear modeling with data from 3,617 adults aged 25 and older who were interviewed up to four times. Self-esteem increased, on average, over the course of the study period. At the same time, significant age variations around this trend were observed, with younger adults experiencing increases in self-esteem and older adults experiencing decreases. In general, race differences were not evident with respect to average levels or rates of change in self-esteem. However, a significant age by race interaction suggested that late life declines in self-esteem were steeper for blacks compared to whites. These findings suggest the presence of age- and race-based stratification with respect to self-esteem. Future work in this area should examine the health and well-being effects of declining self-esteem during old age. PMID:20230130

Vertex- and atlas-based comparisons in measures of cortical thickness, gyrification and white matter volume between humans and chimpanzees.

PubMed

Hopkins, William D; Li, Xiang; Crow, Tim; Roberts, Neil

2017-01-01

What changes in cortical organisation characterise global and localised variation between humans and chimpanzees remains a topic of considerable interest in evolutionary neuroscience. Here, we examined regional variation in cortical thickness, gyrification and white matter in samples of human and chimpanzee brains. Both species were MRI scanned on the same platform using identical procedures. The images were processed and segmented by FSL and FreeSurfer and the relative changes in cortical thickness, gyrification and white matter across the entire cortex were compared between species. In general, relative to chimpanzees, humans had significantly greater gyrification and significantly thinner cortex, particularly in the frontal lobe. Human brains also had disproportionately higher white matter volumes in the frontal lobe, particularly in prefrontal regions. Collectively, the findings suggest that after the split from the common ancestor, white matter expansion and subsequently increasing gyrification occurred in the frontal lobe possibly due to increased selection for human cognitive and motor specialisations.

Cull sow knife-separable lean content evaluation at harvest and lean mass content prediction equation development.

PubMed

Abell, Caitlyn E; Stalder, Kenneth J; Hendricks, Haven B; Fitzgerald, Robert F

2012-07-01

The objectives of this study were to develop a prediction equation for carcass knife-separable lean within and across USDA cull sow market weight classes (MWC) and to determine carcass and individual primal cut knife separable lean content from cull sows. There were significant percent lean and fat differences in the primal cuts across USDA MWC. The two lighter USDA MWC had a greater percent carcass lean and lower percent fat compared to the two heavier MWC. In general, hot carcass weight explained the majority of carcass lean variation. Additionally, backfat was a significant variation source when predicting cull sow carcass lean. The findings support using a single lean prediction equation across MWC to assist processors when making cull sow purchasing decisions and determine the mix of animals from various USDA MWC that will meet their needs when making pork products with defined lean:fat content. Copyright © 2012 Elsevier Ltd. All rights reserved.

Assessment of metals bioaccumulation and bioavailability in mussels Mytilus galloprovincialis exposed to outfalls pollution in coastal areas of Casablanca.

PubMed

Mejdoub, Zineb; Zaid, Younes; Hmimid, Fouzia; Kabine, Mostafa

2018-07-01

The present work aims to study the metallic contamination of four sampling sites located nearby major sewage outfalls of the Casablanca coast (Morocco), using indigenous mussels Mytilus galloprovincialis as bioindicators of pollution. This research offered the opportunity to study trace metals bioaccumulation mechanisms, which represent a major factor in assessment processes of the pollution effects in coastal ecosystem health. The bioavailability and the bioaccumulation of trace metals (Cu, Zn, Ni, Pb) were evaluated in order to compare the metallic contamination in mussels' tissues and find a possible correlation with physiological parameters of this filter feeding species. Our results showed a significant spatiotemporal variation of bioaccumulation, compared to control. A significant correlation coefficient between metals (Zn and Pb) bioavailability and physiological index (CI) was revealed in mussels from the most polluted location. The seasonal variation of trace metal accumulation was also raised; the highest values recorded during the dry period. Copyright © 2018 Elsevier GmbH. All rights reserved.

Thirty-day Readmission Rates and Associated Factors: A Multilevel Analysis of Practice Variations in French Public Psychiatry.

PubMed

Gandré, Coralie; Gervaix, Jeanne; Thillard, Julien; Macé, Jean-Marc; Roelandt, Jean-Luc; Chevreul, Karine

2018-03-01

Inpatient psychiatric readmissions are often used as an indicator of the quality of care and their reduction is in line with international recommendations for mental health care. Research on variations in inpatient readmission rates among mental health care providers is therefore of key importance as these variations can impact equity, quality and efficiency of care when they do not result from differences in patients' needs. Our objectives were first to describe variations in inpatient readmission rates between public mental health care providers in France on a nationwide scale, and second, to identify their association with patient, health care providers and environment characteristics. We carried out a study for the year 2012 using data from ten administrative national databases. 30-day readmissions in inpatient care were identified in the French national psychiatric discharge database. Variations were described numerically and graphically between French psychiatric sectors and factors associated with these variations were identified by carrying out a multi-level logistic regression accounting for the hierarchical structure of the data. Significant practice variations in 30-day inpatient readmission rates were observed with a coefficient of variation above 50%. While a majority of those variations was related to differences within sectors, individual patient characteristics explained a lower part of the variations resulting from differences between sectors than the characteristics of sectors and of their environment. In particular, an increase in the mortality rate and in the acute admission rate for somatic disorders in sectors' catchment area was associated with a decrease in the probability of 30-day readmission. Similarly, an increase in the number of psychiatric inpatient beds in private for-profit hospitals per 1,000 inhabitants in sectors' catchment area was associated with a decrease in this probability, which also varied with overall sectors' case-mix characteristics and with the level of urbanisation of the area. The extent of the variations and the factors associated with it question the adequacy of care and suggest that some of them may be unwarranted. Our findings should however be interpreted in consideration of several limits inherent to data quality and availability as we relied on information from administrative databases. While we considered a wide range of factors potentially associated with variations in 30-day readmissions, our model indeed only explained a limited part of the variations resulting from differences between sectors. Our findings underscored that practice variations in psychiatry are a reality that merits the full attention of decision makers as they can impact the quality, equity and efficiency of care. A specific data system should be established to monitor practice variations in routine to promote transparency and accountability. Few associations were found between variations in 30-day inpatient readmissions and the supply of care. The routine collection of detailed organizational characteristics of health care providers at a national level should be supported to facilitate additional research work, both in France and in other contexts.

An initial investigation of associations between dopamine-linked genetic variation and smoking motives in African Americans.

PubMed

Bidwell, L C; McGeary, J E; Gray, J C; Palmer, R H C; Knopik, V S; MacKillop, J

2015-11-01

Nicotine dependence (ND) is a heterogeneous phenotype with complex genetic influences that may vary across ethnicities. The use of intermediate phenotypes may clarify genetic influences and reveal specific etiological pathways. Prior work in European Americans has found that the four Primary Dependence Motives (PDM) subscales (Automaticity, Craving, Loss of Control, and Tolerance) of the Wisconsin Inventory of Smoking Motives represent core features of nicotine dependence and are promising intermediate phenotypes for understanding genetic pathways to ND. However, no studies have examined PDM as an intermediate phenotype in African American smokers, an ethnic population that displays unique patterns of smoking and genetic variation. In the current study, 268 African American daily smokers completed a phenotypic assessment and provided a sample of DNA. Associations among haplotypes in the NCAM1-TTC12-ANKK1-DRD2 gene cluster, a dopamine-related gene region associated with ND, PDM intermediate phenotypes, and ND were examined. Dopamine-related genetic variation in the DBH and COMT genes was also considered on an exploratory basis. Mediational analysis was used to test the indirect pathway from genetic variation to smoking motives to nicotine dependence. NCAM1-TTC12-ANKK1-DRD2 region variation was significantly associated with the Automaticity subscale and, further, Automaticity significantly mediated associations among NCAM1-TTC12-ANKK1-DRD2 cluster variants and ND. DBH was also significantly associated with Automaticity, Craving, and Tolerance; Automaticity and Tolerance also served as mediators of the DBH-ND relationship. These results suggest that PDM, Automaticity in particular, may be a viable intermediate phenotype for understanding dopamine-related genetic influences on ND in African American smokers. Findings support a model in which putatively dopaminergic variants exert influence on ND through an effect on patterns of automatic routinized smoking. Copyright © 2015 Elsevier Inc. All rights reserved.

Individual Variability in Reproductive Success Determines Winners and Losers under Ocean Acidification: A Case Study with Sea Urchins

PubMed Central

Schlegel, Peter; Havenhand, Jon N.; Gillings, Michael R.; Williamson, Jane E.

2012-01-01

Background Climate change will lead to intense selection on many organisms, particularly during susceptible early life stages. To date, most studies on the likely biotic effects of climate change have focused on the mean responses of pooled groups of animals. Consequently, the extent to which inter-individual variation mediates different selection responses has not been tested. Investigating this variation is important, since some individuals may be preadapted to future climate scenarios. Methodology/Principal Findings We examined the effect of CO2-induced pH changes (“ocean acidification”) in sperm swimming behaviour on the fertilization success of the Australasian sea urchin Heliocidaris erythrogramma, focusing on the responses of separate individuals and pairs. Acidification significantly decreased the proportion of motile sperm but had no effect on sperm swimming speed. Subsequent fertilization experiments showed strong inter-individual variation in responses to ocean acidification, ranging from a 44% decrease to a 14% increase in fertilization success. This was partly explained by the significant relationship between decreases in percent sperm motility and fertilization success at ΔpH = 0.3, but not at ΔpH = 0.5. Conclusions and Significance The effects of ocean acidification on reproductive success varied markedly between individuals. Our results suggest that some individuals will exhibit enhanced fertilization success in acidified oceans, supporting the concept of ‘winners’ and ‘losers’ of climate change at an individual level. If these differences are heritable it is likely that ocean acidification will lead to selection against susceptible phenotypes as well as to rapid fixation of alleles that allow reproduction under more acidic conditions. This selection may ameliorate the biotic effects of climate change if taxa have sufficient extant genetic variation upon which selection can act. PMID:23300876

Dietary variation and mechanical properties of articular cartilage in the temporomandibular joint: implications for the role of plasticity in mechanobiology and pathobiology.

PubMed

Ravosa, Matthew J; Kane, Robert J

2017-10-01

Due to their nature as tissue composites, skeletal joints pose an additional challenge in terms of evaluating the functional significance of morphological variation in their bony and cartilaginous components in response to altered loading conditions. Arguably, this complexity requires more direct means of investigating joint plasticity and performance than typically employed to analyze macro- and micro-anatomical phenomena. To address a significant gap in our understanding of the plasticity of the mammalian temporomandibular joint (TMJ), we investigated the histology and mechanical properties of condylar articular cartilage in rabbits subjected to long-term variation in diet-induced masticatory stresses, specifically cyclical loading. Three cohorts of male weanlings were raised for six months on different diets until adulthood. Following euthanasia, the TMJ condyles on one side were dissected away, fixed, decalcified, dehydrated, embedded and sectioned. Safranin O staining was employed to identify variation in proteoglycan content, which in turn was used to predict patterns of articular cartilage stiffness in contralateral condylar specimens for each treatment group. Hematoxylin and eosin staining was used to quantify diet-induced changes in chondrocyte hypertrophy and cellularity. Mechanical tests document significant decreases in articular cartilage stiffness corresponding to patterns of extracellular matrix relative protein abundance in rabbits subjected to greater cyclical loading. This indicates that TMJs routinely subjected to higher masticatory stresses due to a challenging diet eventually develop postnatal decreases in the ability to counter compressive loads during postcanine biting and chewing. These findings provide novel information regarding TMJ performance, with broader implications about the costs and benefits of phenotypic plasticity as well as implications for how such biological processes affect connective tissue mechanobiology and pathobiology. Copyright © 2017 Elsevier GmbH. All rights reserved.

Is standard deviation of daily PM2.5 concentration associated with respiratory mortality?

PubMed

Lin, Hualiang; Ma, Wenjun; Qiu, Hong; Vaughn, Michael G; Nelson, Erik J; Qian, Zhengmin; Tian, Linwei

2016-09-01

Studies on health effects of air pollution often use daily mean concentration to estimate exposure while ignoring daily variations. This study examined the health effects of daily variation of PM2.5. We calculated daily mean and standard deviations of PM2.5 in Hong Kong between 1998 and 2011. We used a generalized additive model to estimate the association between respiratory mortality and daily mean and variation of PM2.5, as well as their interaction. We controlled for potential confounders, including temporal trends, day of the week, meteorological factors, and gaseous air pollutants. Both daily mean and standard deviation of PM2.5 were significantly associated with mortalities from overall respiratory diseases and pneumonia. Each 10 μg/m(3) increment in daily mean concentration at lag 2 day was associated with a 0.61% (95% CI: 0.19%, 1.03%) increase in overall respiratory mortality and a 0.67% (95% CI: 0.14%, 1.21%) increase in pneumonia mortality. And a 10 μg/m(3) increase in standard deviation at lag 1 day corresponded to a 1.40% (95% CI: 0.35%, 2.46%) increase in overall respiratory mortality, and a 1.80% (95% CI: 0.46%, 3.16%) increase in pneumonia mortality. We also observed a positive but non-significant synergistic interaction between daily mean and variation on respiratory mortality and pneumonia mortality. However, we did not find any significant association with mortality from chronic obstructive pulmonary diseases. Our study suggests that, besides mean concentration, the standard deviation of PM2.5 might be one potential predictor of respiratory mortality in Hong Kong, and should be considered when assessing the respiratory effects of PM2.5. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ethnic variation in melanin content and composition in photoexposed and photoprotected human skin.

PubMed

Alaluf, Simon; Atkins, Derek; Barrett, Karen; Blount, Margaret; Carter, Nik; Heath, Alan

2002-04-01

We have examined the quantity and composition of melanin in both photoprotected (volar upper arm) and chronically photoexposed (dorsal forearm) skin from a range of different ethnic skin types including African, Indian, Mexican, Chinese and European. The most lightly pigmented (European, Chinese and Mexican) skin types have approximately half as much epidermal melanin as the most darkly pigmented (African and Indian) skin types. However, the composition of melanin in these lighter skin types is comparatively more enriched with lightly coloured, alkali-soluble melanin components (up to three-fold). Regardless of ethnicity, epidermal melanin content is significantly greater in chronically photoexposed skin than it is in corresponding photoprotected skin (up to two-fold). However, by comparison there is only a modest enrichment of lightly coloured, alkali soluble melanin components in photoprotected skin (up to 1.3-fold). Analysis of melanosomes extracted from the epidermis in these subjects indicates that the proportion of spheroidal melanosomes is low in all skin types examined (<10%). This suggests that in human skin, pheomelanin is a very minor component of epidermal melanin, even in the lightest (European) skin types. Analysis of melanosome size revealed a significant and progressive variation in size with ethnicity: African skin having the largest melanosomes followed in turn by Indian, Mexican, Chinese and European. On the basis of these findings, we propose that variation in skin pigmentation is strongly influenced by both the amount and the composition (or colour) of the melanin in the epidermis. Variation in melanosome size may also play a significant role. However, the data also suggest that in human skin there are subtle differences in the mechanisms associated with the maintenance of constitutive pigmentation and facultative hyperpigmentation, respectively.

Three-dimensional (3D) geometric morphometric analysis of human premolars to assess sexual dimorphism and biological ancestry in Australian populations.

PubMed

Yong, Robin; Ranjitkar, Sarbin; Lekkas, Dimitra; Halazonetis, Demetrios; Evans, Alistair; Brook, Alan; Townsend, Grant

2018-06-01

This study aimed to investigate size and shape variation of human premolars between Indigenous Australians and Australians of European ancestry, and to assess whether sex and ancestry could be differentiated between these groups using 3D geometric morphometrics. Seventy dental casts from each group, equally subdivided by sex, were scanned using a structured-light scanner. The 3D meshes of upper and lower premolars were processed using geometric morphometric methods. Seventy-two landmarks were recorded for upper premolars and 50 landmarks for lower premolars. For each tooth type, two-way ANOVA was used to assess group differences in centroid size. Shape variations were explored using principal component analysis and visualized using 3D morphing. Two-way Procrustes ANOVA was applied to test group differences for ancestry and sex, and a "leave-one-out" discriminant function was applied to assess group assignment. Centroid size and shape did not display significant difference between the sexes. Centroid size was larger in Indigenous Australians for upper premolars and lower second premolars compared to the Australians of European ancestry. Significant shape variation was noted between the two ancestral groups for upper premolars and the lower first premolar. Correct group assignment of individual teeth to their ancestral groups ranged between 80.0 and 92.8% for upper premolars and 60.0 and 75.7% for lower premolars. Our findings provide evidence of significant size and shape variation in human premolars between the two ancestral groups. High classification rates based on shape analysis of upper premolars highlight potential application of geometric morphometrics in anthropological, bioarcheological and forensic contexts. © 2018 Wiley Periodicals, Inc.

Schizotypal traits in a non-clinical sample from Hawai'i.

PubMed

Schiffman, Jason

2004-03-01

Most research investigating schizotypal traits, and linking schizotypal personality disorder (SPD) to later schizophrenia, has used Caucasian samples. The lack of cross-cultural comparisons on SPD trait scales inhibits confidence in generalizing the link between SPD and schizophrenia to non-Caucasian populations. The few studies investigating cross-cultural rates of schizotypal traits in non-clinical samples report mixed findings with respect to cultural variation. This study report rates of schizotypal traits in an ethnically and culturally diverse non-clinical sample (N = 353) in the state of Hawaii using the Schizotypai Personality Disorder Questionnaire-B (SPQ-B). Analyses did not detect significantly elevated rates between ethnic groups on the Cognitive/Perceptual, Disorganized, or Total SPQ Score Scales. Significant differences between Caucasians and Asians, as well as between Caucasians and Mixed Ethnicity on the SPQ-B Interpersonal Scale suggest relatively less shyness and more sociability in the Caucasian group. Generally, findings of no significant differences between ethnic groups on the SPQ-B suggest that rates of schizotypy are similar across ethnic groups in Hawaii.

The Sun's Seismic Radius as Measured from the Fundamental Modes of Oscillations and Its Implications for the TSI Variations

NASA Astrophysics Data System (ADS)

Jain, Kiran; Tripathy, S. C.; Hill, F.

2018-05-01

In this Letter we explore the relationship between the solar seismic radius and total solar irradiance (TSI) during the last two solar cycles using the uninterrupted data from space-borne instruments on board the Solar and Heliospheric Observatory (SoHO) and the Solar Dynamics Observatory (SDO). The seismic radius is calculated from the fundamental (f) modes of solar oscillations utilizing the observations from SoHO/Michelson Doppler Imager (MDI) and SDO/Helioseismic and Magnetic Imager (HMI), and the TSI measurements are obtained from SoHO/VIRGO. Our study suggests that the major contribution to the TSI variation arises from the changes in magnetic field, while the radius variation plays a secondary role. We find that the solar irradiance increases with decreasing seismic radius; however, the anti-correlation between them is moderately weak. The estimated maximum change in seismic radius during a solar cycle is about 5 km, and is consistent in both solar cycles 23 and 24. Previous studies ;suggest a radius change at the surface of the order of 0.06 arcsec to explain the 0.1% variation in the TSI values during the solar cycle; however, our inferred seismic radius change is significantly smaller, hence the TSI variations cannot be fully explained by the temporal changes in seismic radius.

Excess congenital non-synonymous variation in leukemia-associated genes in MLL− infant leukemia: a Children's Oncology Group report

PubMed Central

Valentine, M C; Linabery, A M; Chasnoff, S; Hughes, A E O; Mallaney, C; Sanchez, N; Giacalone, J; Heerema, N A; Hilden, J M; Spector, L G; Ross, J A; Druley, T E

2014-01-01

Infant leukemia (IL) is a rare sporadic cancer with a grim prognosis. Although most cases are accompanied by MLL rearrangements and harbor very few somatic mutations, less is known about the genetics of the cases without MLL translocations. We performed the largest exome-sequencing study to date on matched non-cancer DNA from pairs of mothers and IL patients to characterize congenital variation that may contribute to early leukemogenesis. Using the COSMIC database to define acute leukemia-associated candidate genes, we find a significant enrichment of rare, potentially functional congenital variation in IL patients compared with randomly selected genes within the same patients and unaffected pediatric controls. IL acute myeloid leukemia (AML) patients had more overall variation than IL acute lymphocytic leukemia (ALL) patients, but less of that variation was inherited from mothers. Of our candidate genes, we found that MLL3 was a compound heterozygote in every infant who developed AML and 50% of infants who developed ALL. These data suggest a model by which known genetic mechanisms for leukemogenesis could be disrupted without an abundance of somatic mutation or chromosomal rearrangements. This model would be consistent with existing models for the establishment of leukemia clones in utero and the high rate of IL concordance in monozygotic twins. PMID:24301523

Linking the serotonin transporter gene, family environments, hippocampal volume and depression onset: A prospective imaging gene × environment analysis.

PubMed

Little, Keriann; Olsson, Craig A; Youssef, George J; Whittle, Sarah; Simmons, Julian G; Yücel, Murat; Sheeber, Lisa B; Foley, Debra L; Allen, Nicholas B

2015-11-01

A single imaging gene-environment (IGxE) framework that is able to simultaneously model genetic, neurobiological, and environmental influences on psychopathology outcomes is needed to improve understanding of how complex interrelationships between allelic variation, differences in neuroanatomy or neuroactivity, and environmental experience affect risk for psychiatric disorder. In a longitudinal study of adolescent development we demonstrate the utility of such an IGxE framework by testing whether variation in parental behavior at age 12 altered the strength of an imaging genetics pathway, involving an indirect association between allelic variation in the serotonin transporter gene to variation in hippocampal volume and consequent onset of major depressive disorder by age 18. Results were consistent with the presence of an indirect effect of the serotonin transporter S-allele on depression onset via smaller left and right hippocampal volumes that was significant only in family environments involving either higher levels of parental aggression or lower levels of positive parenting. The previously reported finding of S-allele carriers' increased risk of depression in adverse environments may, therefore, be partly because of the effects of these environments on a neurobiological pathway from the serotonin transporter gene to depression onset that proceeds through variation in hippocampal volume. (c) 2015 APA, all rights reserved).

Genetics of hybrid male sterility among strains and species in the Drosophila pseudoobscura species group

PubMed Central

McDermott, Shannon R.; Noor, Mohamed A. F.

2011-01-01

Taxa in the early stages of speciation may bear intraspecific allelic variation at loci conferring barrier traits in hybrids such as hybrid sterility. Additionally, hybridization may spread alleles that confer barrier traits to other taxa. Historically, few studies examine within- and between-species variation at loci conferring reproductive isolation. Here, we test for allelic variation within Drosophila persimilis and within the Bogota subspecies of D. pseudoobscura at regions previously shown to contribute to hybrid male sterility. We also test whether D. persimilis and the USA subspecies of D. pseudoobscura share an allele conferring hybrid sterility in a D. pseudoobscura bogotana genetic background. All loci conferred similar hybrid sterility effects across all strains studied, though we detected some statistically significant quantitative effect variation among D. persimilis alleles of some hybrid incompatibility QTLs. We also detected allelism between D. persimilis and D. pseudoobscura USA at a 2nd chromosome hybrid sterility QTL. We hypothesize that either the QTL is ancestral in D. persimilis and D. pseudoobscura USA and lost in D. pseudoobscura bogotana, or gene flow transferred the QTL from D. persimilis to D. pseudoobscura USA. We discuss our findings in the context of population features that may contribute to variation in hybrid incompatibilities. PMID:21729052

Genetics of hybrid male sterility among strains and species in the Drosophila pseudoobscura species group.

PubMed

McDermott, Shannon R; Noor, Mohamed A F

2011-07-01

Taxa in the early stages of speciation may bear intraspecific allelic variation at loci conferring barrier traits in hybrids such as hybrid sterility. Additionally, hybridization may spread alleles that confer barrier traits to other taxa. Historically, few studies examine within- and between-species variation at loci conferring reproductive isolation. Here, we test for allelic variation within Drosophila persimilis and within the Bogota subspecies of D. pseudoobscura at regions previously shown to contribute to hybrid male sterility. We also test whether D. persimilis and the USA subspecies of D. pseudoobscura share an allele conferring hybrid sterility in a D. pseudoobscura bogotana genetic background. All loci conferred similar hybrid sterility effects across all strains studied, although we detected some statistically significant quantitative effect variation among D. persimilis alleles of some hybrid incompatibility QTLs. We also detected allelism between D. persimilis and D. pseudoobscura USA at a second chromosome hybrid sterility QTL. We hypothesize that either the QTL is ancestral in D. persimilis and D. pseudoobscura USA and lost in D. pseudoobscura bogotana, or gene flow transferred the QTL from D. persimilis to D. pseudoobscura USA. We discuss our findings in the context of population features that may contribute to variation in hybrid incompatibilities. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Genes, Economics, and Happiness *

PubMed Central

De Neve, Jan-Emmanuel; Christakis, Nicholas A.; Fowler, James H.; Frey, Bruno S.

2012-01-01

We explore the influence of genetic variation on subjective well-being by employing a twin design and genetic association study. In a nationally-representative twin sample, we first show that about 33% of the variation in life satisfaction is explained by genetic variation. Although previous studies have shown that baseline happiness is significantly heritable, little research has considered molecular genetic associations with subjective well-being. We study the relationship between a functional polymorphism on the serotonin transporter gene (5-HTTLPR) and life satisfaction. We initially find that individuals with the longer, transcriptionally more efficient variant of this genotype report greater life satisfaction (n=2,545, p=0.012). However, our replication attempts on independent samples produce mixed results indicating that more work needs to be done to better understand the relationship between this genotype and subjective well-being. This work has implications for how economists think about the determinants of utility, and the extent to which exogenous shocks might affect individual well-being. PMID:24349601

Nonlinear Network Description for Many-Body Quantum Systems in Continuous Space

NASA Astrophysics Data System (ADS)

Ruggeri, Michele; Moroni, Saverio; Holzmann, Markus

2018-05-01

We show that the recently introduced iterative backflow wave function can be interpreted as a general neural network in continuum space with nonlinear functions in the hidden units. Using this wave function in variational Monte Carlo simulations of liquid 4He in two and three dimensions, we typically find a tenfold increase in accuracy over currently used wave functions. Furthermore, subsequent stages of the iteration procedure define a set of increasingly good wave functions, each with its own variational energy and variance of the local energy: extrapolation to zero variance gives energies in close agreement with the exact values. For two dimensional 4He, we also show that the iterative backflow wave function can describe both the liquid and the solid phase with the same functional form—a feature shared with the shadow wave function, but now joined by much higher accuracy. We also achieve significant progress for liquid 3He in three dimensions, improving previous variational and fixed-node energies.

Mental health in American colleges and universities: variation across student subgroups and across campuses.

PubMed

Eisenberg, Daniel; Hunt, Justin; Speer, Nicole

2013-01-01

We estimated the prevalence and correlates of mental health problems among college students in the United States. In 2007 and 2009, we administered online surveys with brief mental health screens to random samples of students at 26 campuses nationwide. We used sample probability weights to adjust for survey nonresponse. A total of 14,175 students completed the survey, corresponding to a 44% participation rate. The prevalence of positive screens was 17.3% for depression, 4.1% for panic disorder, 7.0% for generalized anxiety, 6.3% for suicidal ideation, and 15.3% for nonsuicidal self-injury. Mental health problems were significantly associated with sex, race/ethnicity, religiosity, relationship status, living on campus, and financial situation. The prevalence of conditions varied substantially across the campuses, although campus-level variation was still a small proportion of overall variation in student mental health. The findings offer a starting point for identifying individual and contextual factors that may be useful to target in intervention strategies.

Productivity and sea surface temperature are correlated with the pelagic larval duration of damselfishes in the Red Sea.

PubMed

Robitzch, Vanessa S N; Lozano-Cortés, Diego; Kandler, Nora M; Salas, Eva; Berumen, Michael L

2016-04-30

We examined the variation of pelagic larval durations (PLDs) among three damselfishes, Dascyllus aruanus, D. marginatus, and D. trimaculatus, which live under the influence of an environmental gradient in the Red Sea. PLDs were significantly correlated with latitude, sea surface temperature (SST), and primary production (CHLA; chlorophyll a concentrations). We find a consistent decrease in PLDs with increasing SST and primary production (CHLA) towards the southern Red Sea among all species. This trend is likely related to higher food availability and increased metabolic rates in that region. We suggest that food availability is a potentially stronger driver of variation in PLD than temperature, especially in highly oligotrophic regions. Additionally, variations in PLDs were particularly high among specimens of D. marginatus, suggesting a stronger response to local environmental differences for endemic species. We also report the first average PLD for this species over a broad geographic range (19.82 ± 2.92 days). Copyright © 2015 Elsevier Ltd. All rights reserved.

Observations of hysteresis in solar cycle variations among seven solar activity indicators

NASA Technical Reports Server (NTRS)

Bachmann, Kurt T.; White, Oran R.

1994-01-01

We show that smoothed time series of 7 indices of solar activity exhibit significant solar cycle dependent differences in their relative variations during the past 20 years. In some cases these observed hysteresis patterns start to repeat over more than one solar cycle, giving evidence that this is a normal feature of solar variability. Among the indices we study, we find that the hysteresis effects are approximately simple phase shifts, and we quantify these phase shifts in terms of lag times behind the leading index, the International Sunspot Number. Our measured lag times range from less than one month to greater than four months and can be much larger than lag times estimated from short-term variations of these same activity indices during the emergence and decay of major active regions. We argue that hysteresis represents a real delay in the onset and decline of solar activity and is an important clue in the search for physical processes responsible for changing solar emission at various wavelengths.

An overview of maternal separation effects on behavioural outcomes in mice: Evidence from a four-stage methodological systematic review.

PubMed

Tractenberg, Saulo G; Levandowski, Mateus L; de Azeredo, Lucas Araújo; Orso, Rodrigo; Roithmann, Laura G; Hoffmann, Emerson S; Brenhouse, Heather; Grassi-Oliveira, Rodrigo

2016-09-01

Early life stress (ELS) developmental effects have been widely studied by preclinical researchers. Despite the growing body of evidence from ELS models, such as the maternal separation paradigm, the reported results have marked inconsistencies. The maternal separation model has several methodological pitfalls that could influence the reliability of its results. Here, we critically review 94 mice studies that addressed the effects of maternal separation on behavioural outcomes. We also discuss methodological issues related to the heterogeneity of separation protocols and the quality of reporting methods. Our findings indicate a lack of consistency in maternal separation effects: major studies of behavioural and biological phenotypes failed to find significant deleterious effects. Furthermore, we identified several specific variations in separation methodological procedures. These methodological variations could contribute to the inconsistency of maternal separation effects by producing different degrees of stress exposure in maternal separation-reared pups. These methodological problems, together with insufficient reporting, might lead to inaccurate and unreliable effect estimates in maternal separation studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Status and progress in coral reef disease research.

PubMed

Weil, Ernesto; Smith, Garriet; Gil-Agudelo, Diego L

2006-03-23

Recent findings on the ecology, etiology and pathology of coral pathogens, host resistance mechanisms, previously unknown disease/syndromes and the global nature of coral reef diseases have increased our concern about the health and future of coral reef communities. Much of what has been discovered in the past 4 years is presented in this special issue. Among the significant findings, the role that various Vibrio species play in coral disease and health, the composition of the 'normal microbiota' of corals, and the possible role of viruses in the disease process are important additions to our knowledge. New information concerning disease resistance and vectors, variation in pathogen composition for both fungal diseases of gorgonians and black band disease across oceans, environmental effects on disease susceptibility and resistance, and temporal and spatial disease variations among different coral species is presented in a number of papers. While the Caribbean may still be the 'disease hot spot' for coral reefs, it is now clear that diseases of coral reef organisms have become a global threat to coral reefs and a major cause of reef deterioration.

Lower body symmetry and running performance in elite Jamaican track and field athletes.

PubMed

Trivers, Robert; Fink, Bernhard; Russell, Mark; McCarty, Kristofor; James, Bruce; Palestis, Brian G

2014-01-01

In a study of degree of lower body symmetry in 73 elite Jamaican track and field athletes we show that both their knees and ankles (but not their feet) are-on average-significantly more symmetrical than those of 116 similarly aged controls from the rural Jamaican countryside. Within the elite athletes, events ranged from the 100 to the 800 m, and knee and ankle asymmetry was lower for those running the 100 m dashes than those running the longer events with turns. Nevertheless, across all events those with more symmetrical knees and ankles (but not feet) had better results compared to international standards. Regression models considering lower body symmetry combined with gender, age and weight explain 27 to 28% of the variation in performance among athletes, with symmetry related to about 5% of this variation. Within 100 m sprinters, the results suggest that those with more symmetrical knees and ankles ran faster. Altogether, our work confirms earlier findings that knee and probably ankle symmetry are positively associated with sprinting performance, while extending these findings to elite athletes.

Assessing variation in tolerance in 23 Muslim-majority and Western countries.

PubMed

Milligan, Scott; Andersen, Robert; Brym, Robert

2014-08-01

Scholars disagree over whether Islam hinders the development of liberal democracy in Muslim-majority countries. We contribute to this debate by assessing the influence of Islam at the individual and national levels on ethnic, racial, and religious tolerance in 23 countries. Our analyses are based on a set of multilevel models fitted to World Values Survey data and national-level contextual information from various sources. Our findings suggest that people living in Muslim-majority countries tend to be less tolerant than are those living in Western countries. Although a significant part of this difference is attributable to variation in level of economic development and income inequality, Muslim countries remain less tolerant even after controlling for these factors. On the other hand, controlling for other individual-level factors, nonpracticing Muslims in Western countries are more tolerant than are all others in both Muslim-majority and Western countries. This finding challenges common claims about the effects of Islam as a religion on tolerance, suggesting that it is Islamic political regimes--not Islam itself--that pose problems for social tolerance.

Lower Body Symmetry and Running Performance in Elite Jamaican Track and Field Athletes

PubMed Central

Trivers, Robert; Fink, Bernhard; Russell, Mark; McCarty, Kristofor; James, Bruce; Palestis, Brian G.

2014-01-01

In a study of degree of lower body symmetry in 73 elite Jamaican track and field athletes we show that both their knees and ankles (but not their feet) are–on average–significantly more symmetrical than those of 116 similarly aged controls from the rural Jamaican countryside. Within the elite athletes, events ranged from the 100 to the 800 m, and knee and ankle asymmetry was lower for those running the 100 m dashes than those running the longer events with turns. Nevertheless, across all events those with more symmetrical knees and ankles (but not feet) had better results compared to international standards. Regression models considering lower body symmetry combined with gender, age and weight explain 27 to 28% of the variation in performance among athletes, with symmetry related to about 5% of this variation. Within 100 m sprinters, the results suggest that those with more symmetrical knees and ankles ran faster. Altogether, our work confirms earlier findings that knee and probably ankle symmetry are positively associated with sprinting performance, while extending these findings to elite athletes. PMID:25401732

Individual variation in cone photoreceptor density in house sparrows: implications for between-individual differences in visual resolution and chromatic contrast.

PubMed

Ensminger, Amanda L; Fernández-Juricic, Esteban

2014-01-01

Between-individual variation has been documented in a wide variety of taxa, especially for behavioral characteristics; however, intra-population variation in sensory systems has not received similar attention in wild animals. We measured a key trait of the visual system, the density of retinal cone photoreceptors, in a wild population of house sparrows (Passer domesticus). We tested whether individuals differed from each other in cone densities given within-individual variation across the retina and across eyes. We further tested whether the existing variation could lead to individual differences in two aspects of perception: visual resolution and chromatic contrast. We found consistent between-individual variation in the densities of all five types of avian cones, involved in chromatic and achromatic vision. Using perceptual modeling, we found that this degree of variation translated into significant between-individual differences in visual resolution and the chromatic contrast of a plumage signal that has been associated with mate choice and agonistic interactions. However, there was no evidence for a relationship between individual visual resolution and chromatic contrast. The implication is that some birds may have the sensory potential to perform "better" in certain visual tasks, but not necessarily in both resolution and contrast simultaneously. Overall, our findings (a) highlight the need to consider multiple individuals when characterizing sensory traits of a species, and (b) provide some mechanistic basis for between-individual variation in different behaviors (i.e., animal personalities) and for testing the predictions of several widely accepted hypotheses (e.g., honest signaling).

Individual Variation in Cone Photoreceptor Density in House Sparrows: Implications for Between-Individual Differences in Visual Resolution and Chromatic Contrast

PubMed Central

Ensminger, Amanda L.; Fernández-Juricic, Esteban

2014-01-01

Between-individual variation has been documented in a wide variety of taxa, especially for behavioral characteristics; however, intra-population variation in sensory systems has not received similar attention in wild animals. We measured a key trait of the visual system, the density of retinal cone photoreceptors, in a wild population of house sparrows (Passer domesticus). We tested whether individuals differed from each other in cone densities given within-individual variation across the retina and across eyes. We further tested whether the existing variation could lead to individual differences in two aspects of perception: visual resolution and chromatic contrast. We found consistent between-individual variation in the densities of all five types of avian cones, involved in chromatic and achromatic vision. Using perceptual modeling, we found that this degree of variation translated into significant between-individual differences in visual resolution and the chromatic contrast of a plumage signal that has been associated with mate choice and agonistic interactions. However, there was no evidence for a relationship between individual visual resolution and chromatic contrast. The implication is that some birds may have the sensory potential to perform “better” in certain visual tasks, but not necessarily in both resolution and contrast simultaneously. Overall, our findings (a) highlight the need to consider multiple individuals when characterizing sensory traits of a species, and (b) provide some mechanistic basis for between-individual variation in different behaviors (i.e., animal personalities) and for testing the predictions of several widely accepted hypotheses (e.g., honest signaling). PMID:25372039

Spiders do not escape reproductive manipulations by Wolbachia

PubMed Central

2011-01-01

Background Maternally inherited bacteria that reside obligatorily or facultatively in arthropods can increase their prevalence in the population by altering their hosts' reproduction. Such reproductive manipulations have been reported from the major arthropod groups such as insects (in particular hymenopterans, butterflies, dipterans and beetles), crustaceans (isopods) and mites. Despite the observation that endosymbiont bacteria are frequently encountered in spiders and that the sex ratio of particular spider species is strongly female biased, a direct relationship between bacterial infection and sex ratio variation has not yet been demonstrated for this arthropod order. Results Females of the dwarf spider Oedothorax gibbosus exhibit considerable variation in the sex ratio of their clutches and were infected with at least three different endosymbiont bacteria capable of altering host reproduction i.e. Wolbachia, Rickettsia and Cardinium. Breeding experiments show that sex ratio variation in this species is primarily maternally inherited and that removal of the bacteria by antibiotics restores an unbiased sex ratio. Moreover, clutches of females infected with Wolbachia were significantly female biased while uninfected females showed an even sex ratio. As female biased clutches were of significantly smaller size compared to non-distorted clutches, killing of male embryos appears to be the most likely manipulative effect. Conclusions This represents to our knowledge the first direct evidence that endosymbiont bacteria, and in particular Wolbachia, might induce sex ratio variation in spiders. These findings are pivotal to further understand the diversity of reproductive phenotypes observed in this arthropod order. PMID:21235755

Genetic diversity and species diversity of stream fishes covary across a land-use gradient.

PubMed

Blum, Michael J; Bagley, Mark J; Walters, David M; Jackson, Suzanne A; Daniel, F Bernard; Chaloud, Deborah J; Cade, Brian S

2012-01-01

Genetic diversity and species diversity are expected to covary according to area and isolation, but may not always covary with environmental heterogeneity. In this study, we examined how patterns of genetic and species diversity in stream fishes correspond to local and regional environmental conditions. To do so, we compared population size, genetic diversity and divergence in central stonerollers (Campostoma anomalum) to measures of species diversity and turnover in stream fish assemblages among similarly sized watersheds across an agriculture-forest land-use gradient in the Little Miami River basin (Ohio, USA). Significant correlations were found in many, but not all, pair-wise comparisons. Allelic richness and species richness were strongly correlated, for example, but diversity measures based on allele frequencies and assemblage structure were not. In-stream conditions related to agricultural land use were identified as significant predictors of genetic diversity and species diversity. Comparisons to population size indicate, however, that genetic diversity and species diversity are not necessarily independent and that variation also corresponds to watershed location and glaciation history in the drainage basin. Our findings demonstrate that genetic diversity and species diversity can covary in stream fish assemblages, and illustrate the potential importance of scaling observations to capture responses to hierarchical environmental variation. More comparisons according to life history variation could further improve understanding of conditions that give rise to parallel variation in genetic diversity and species diversity, which in turn could improve diagnosis of anthropogenic influences on aquatic ecosystems.

Temporal variation in groundwater quality in the Permian Basin of Texas, a region of increasing unconventional oil and gas development.

PubMed

Hildenbrand, Zacariah L; Carlton, Doug D; Fontenot, Brian E; Meik, Jesse M; Walton, Jayme L; Thacker, Jonathan B; Korlie, Stephanie; Shelor, C Phillip; Kadjo, Akinde F; Clark, Adelaide; Usenko, Sascha; Hamilton, Jason S; Mach, Phillip M; Verbeck, Guido F; Hudak, Paul; Schug, Kevin A

2016-08-15

The recent expansion of natural gas and oil extraction using unconventional oil and gas development (UD) practices such as horizontal drilling and hydraulic fracturing has raised questions about the potential for environmental impacts. Prior research has focused on evaluations of air and water quality in particular regions without explicitly considering temporal variation; thus, little is known about the potential effects of UD activity on the environment over longer periods of time. Here, we present an assessment of private well water quality in an area of increasing UD activity over a period of 13months. We analyzed samples from 42 private water wells located in three contiguous counties on the Eastern Shelf of the Permian Basin in Texas. This area has experienced a rise in UD activity in the last few years, and we analyzed samples in four separate time points to assess variation in groundwater quality over time as UD activities increased. We monitored general water quality parameters as well as several compounds used in UD activities. We found that some constituents remained stable over time, but others experienced significant variation over the period of study. Notable findings include significant changes in total organic carbon and pH along with ephemeral detections of ethanol, bromide, and dichloromethane after the initial sampling phase. These data provide insight into the potentially transient nature of compounds associated with groundwater contamination in areas experiencing UD activity. Copyright © 2016 Elsevier B.V. All rights reserved.

State variations in women's socioeconomic status and use of modern contraceptives in Nigeria.

PubMed

Lamidi, Esther O

2015-01-01

According to the 2014 World Population Data Sheet, Nigeria has one of the highest fertility and lowest contraceptive prevalence rates around the world. However, research suggests that national contraceptive prevalence rate overshadows enormous spatial variations in reproductive behavior in the country. I examined the variations in women's socioeconomic status and modern contraceptive use across states in Nigeria. Using the 2013 Nigeria Demographic and Health Survey data (n = 18,910), I estimated the odds of modern contraceptive use among sexually active married and cohabiting women in a series of multilevel logistic regression models. The share of sexually active, married and cohabiting women using modern contraceptives widely varied, from less than one percent in Kano, Yobe, and Jigawa states, to 40 percent in Osun state. Most of the states with low contraceptive prevalence rates also ranked low on women's socioeconomic attributes. Results of multilevel logistic regression analyses showed that women residing in states with greater shares of women with secondary or higher education, higher female labor force participation rates, and more women with health care decision-making power, had significantly higher odds of using modern contraceptives. Differences in women's participation in health care decisions across states remained significantly associated with modern contraceptive use, net of individual-level socioeconomic status and other covariates of modern contraceptive use. Understanding of state variations in contraceptive use is crucial to the design and implementation of family planning programs. The findings reinforce the need for state-specific family planning programs in Nigeria.

Genetic diversity and species diversity of stream fishes covary across a land-use gradient

USGS Publications Warehouse

Blum, M.J.; Bagley, M.J.; Walters, D.M.; Jackson, S.A.; Daniel, F.B.; Chaloud, D.J.; Cade, B.S.

2012-01-01

Genetic diversity and species diversity are expected to covary according to area and isolation, but may not always covary with environmental heterogeneity. In this study, we examined how patterns of genetic and species diversity in stream fishes correspond to local and regional environmental conditions. To do so, we compared population size, genetic diversity and divergence in central stonerollers (Campostoma anomalum) to measures of species diversity and turnover in stream fish assemblages among similarly sized watersheds across an agriculture-forest land-use gradient in the Little Miami River basin (Ohio, USA). Significant correlations were found in many, but not all, pair-wise comparisons. Allelic richness and species richness were strongly correlated, for example, but diversity measures based on allele frequencies and assemblage structure were not. In-stream conditions related to agricultural land use were identified as significant predictors of genetic diversity and species diversity. Comparisons to population size indicate, however, that genetic diversity and species diversity are not necessarily independent and that variation also corresponds to watershed location and glaciation history in the drainage basin. Our findings demonstrate that genetic diversity and species diversity can covary in stream fish assemblages, and illustrate the potential importance of scaling observations to capture responses to hierarchical environmental variation. More comparisons according to life history variation could further improve understanding of conditions that give rise to parallel variation in genetic diversity and species diversity, which in turn could improve diagnosis of anthropogenic influences on aquatic ecosystems. ?? 2011 Springer-Verlag.

Weather and childbirth: a further search for relationships.

PubMed

Driscoll, D M

1995-03-01

Previous attempts to find relationships between weather and parturition (childbirth) and its onset (the beginning of labor pains) have revealed, firstly, limited but statistically significant relationships between weather conditions much colder than the day before, with high winds and low pressure, and increased onsets; and secondly, increased numbers of childbirths during periods of atmospheric pressure rise (highly statistically significant). To test these findings, this study examined weather data coincident childbirth data from a hospital at Bryan-College Station, Texas (for a period of 30 cool months from 1987 to 1992). Tests for (1) days of cold fronts, (2) a day before and a day after the cold front, (3) days with large temperature increases, and (4) decreases from the day before revealed no relationship with mean daily rate of onset. Cold days with high winds and low pressure had significantly fewer onsets, a result that is the opposite of previous findings. The postulated relationship between periods of pressure rise and increased birth frequency was negative, i.e., significantly fewer births occurred at those times--again, the opposite of the apparent occurrence in an earlier study. The coincidence of diurnal variations in both atmospheric pressure and frequency of childbirths, was shown to account for fairly strong negative associations between the two variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in dopamine levels and locomotor activity in response to selection on virgin lifespan in Drosophila melanogaster.

PubMed

Vermeulen, C J; Cremers, T I F H; Westerink, B H C; Van De Zande, L; Bijlsma, R

2006-07-01

Among various other mechanisms, genetic differences in the production of reactive oxygen species are thought to underlie genetic variation for longevity. Here we report on possible changes in ROS production related processes in response to selection for divergent virgin lifespan in Drosophila. The selection lines were observed to differ significantly in dopamine levels and melanin pigmentation, which is associated with dopamine levels at eclosion. These findings confirm that variation in dopamine levels is associated with genetic variation for longevity. Dopamine has previously been implied in ROS production and in the occurrence of age-related neurodegenerative diseases. In addition, we propose a possible proximate mechanism by which dopamine levels affect longevity in Drosophila: We tested if increased dopamine levels were associated with a "rate-of-living" syndrome of increased activity and respiration levels, thus aggravating the level of oxidative stress. Findings on locomotor activity and oxygen consumption of short-lived flies were in line with expectations. However, the relation is not straightforward, as flies of the long-lived lines did not show any consistent differences in pigmentation or dopamine levels with respect to the control lines. Moreover, long-lived flies also had increased locomotor activity, but showed no consistent differences in respiration rate. This strongly suggests that the response for increased and decreased lifespan may be obtained by different mechanisms.

RESPECT-ED: Rates of Pulmonary Emboli (PE) and Sub-Segmental PE with Modern Computed Tomographic Pulmonary Angiograms in Emergency Departments: A Multi-Center Observational Study Finds Significant Yield Variation, Uncorrelated with Use or Small PE Rates.

PubMed

Mountain, David; Keijzers, Gerben; Chu, Kevin; Joseph, Anthony; Read, Catherine; Blecher, Gabriel; Furyk, Jeremy; Bharat, Chrianna; Velusamy, Karthik; Munro, Andrew; Baker, Kylie; Kinnear, Frances; Mukherjee, Ahses; Watkins, Gina; Buntine, Paul; Livesay, Georgia; Fatovich, Daniel

2016-01-01

Overuse of CT Pulmonary Angiograms (CTPA) for diagnosing pulmonary embolism (PE), particularly in Emergency Departments (ED), is considered problematic. Marked variations in positive CTPA rates are reported, with American 4-10% yields driving most concerns. Higher resolution CTPA may increase sub-segmental PE (SSPE) diagnoses, which may be up to 40% false positive. Excessive use and false positives could increase harm vs. benefit. These issues have not been systematically examined outside America. To describe current yield variation and CTPA utilisation in Australasian ED, exploring potential factors correlated with variation. A retrospective multi-centre review of consecutive ED-ordered CTPA using standard radiology reports. ED CTPA report data were inputted onto preformatted data-sheets. The primary outcome was site level yield, analysed both intra-site and against a nominated 15.3% yield. Factors potentially associated with yield were assessed for correlation. Fourteen radiology departments (15 ED) provided 7077 CTPA data (94% ≥64-slice CT); PE were reported in 1028 (yield 14.6% (95%CI 13.8-15.4%; range 9.3-25.3%; site variation p <0.0001) with four sites significantly below and one above the 15.3% target. Admissions, CTPA usage, PE diagnosis rates and size of PE were uncorrelated with yield. Large PE (≥lobar) were 55% (CI: 52.1-58.2%) and SSPE 8.8% (CI: 7.1-10.5%) of positive scans. CTPA usage (0.2-1.5% adult attendances) was correlated (p<0.006) with PE diagnosis but not SSPE: large PE proportions. We found significant intra-site CTPA yield variation within Australasia. Yield was not clearly correlated with CTPA usage or increased small PE rates. Both SSPE and large PE rates were similar to higher yield historical cohorts. CTPA use was considerably below USA 2.5-3% rates. Higher CTPA utilisation was positively correlated with PE diagnoses, but without evidence of increased proportions of small PE. This suggests that increased diagnoses seem to be of clinically relevant sized PE.

Variations of deep soil moisture under different vegetation types and influencing factors in a watershed of the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Fang, Xuening; Zhao, Wenwu; Wang, Lixin; Feng, Qiang; Ding, Jingyi; Liu, Yuanxin; Zhang, Xiao

2016-08-01

Soil moisture in deep soil layers is a relatively stable water resource for vegetation growth in the semi-arid Loess Plateau of China. Characterizing the variations in deep soil moisture and its influencing factors at a moderate watershed scale is important to ensure the sustainability of vegetation restoration efforts. In this study, we focus on analyzing the variations and factors that influence the deep soil moisture (DSM) in 80-500 cm soil layers based on a soil moisture survey of the Ansai watershed in Yan'an in Shanxi Province. Our results can be divided into four main findings. (1) At the watershed scale, higher variations in the DSM occurred at 120-140 and 480-500 cm in the vertical direction. At the comparable depths, the variation in the DSM under native vegetation was much lower than that in human-managed vegetation and introduced vegetation. (2) The DSM in native vegetation and human-managed vegetation was significantly higher than that in introduced vegetation, and different degrees of soil desiccation occurred under all the introduced vegetation types. Caragana korshinskii and black locust caused the most serious desiccation. (3) Taking the DSM conditions of native vegetation as a reference, the DSM in this watershed could be divided into three layers: (i) a rainfall transpiration layer (80-220 cm); (ii) a transition layer (220-400 cm); and (iii) a stable layer (400-500 cm). (4) The factors influencing DSM at the watershed scale varied with vegetation types. The main local controls of the DSM variations were the soil particle composition and mean annual rainfall; human agricultural management measures can alter the soil bulk density, which contributes to higher DSM in farmland and apple orchards. The plant growth conditions, planting density, and litter water holding capacity of introduced vegetation showed significant relationships with the DSM. The results of this study are of practical significance for vegetation restoration strategies, especially for the choice of vegetation types, planting zones, and proper human management measures.

Gender Differences in Associations of Glutamate Decarboxylase 1 Gene (GAD1) Variants with Panic Disorder

PubMed Central

Weber, Heike; Scholz, Claus Jürgen; Domschke, Katharina; Baumann, Christian; Klauke, Benedikt; Jacob, Christian P.; Maier, Wolfgang; Fritze, Jürgen; Bandelow, Borwin; Zwanzger, Peter Michael; Lang, Thomas; Fehm, Lydia; Ströhle, Andreas; Hamm, Alfons; Gerlach, Alexander L.; Alpers, Georg W.; Kircher, Tilo; Wittchen, Hans-Ulrich; Arolt, Volker; Pauli, Paul; Deckert, Jürgen; Reif, Andreas

2012-01-01

Background Panic disorder is common (5% prevalence) and females are twice as likely to be affected as males. The heritable component of panic disorder is estimated at 48%. Glutamic acid dehydrogenase GAD1, the key enzyme for the synthesis of the inhibitory and anxiolytic neurotransmitter GABA, is supposed to influence various mental disorders, including mood and anxiety disorders. In a recent association study in depression, which is highly comorbid with panic disorder, GAD1 risk allele associations were restricted to females. Methodology/Principal Findings Nineteen single nucleotide polymorphisms (SNPs) tagging the common variation in GAD1 were genotyped in two independent gender and age matched case-control samples (discovery sample n = 478; replication sample n = 584). Thirteen SNPs passed quality control and were examined for gender-specific enrichment of risk alleles associated with panic disorder by using logistic regression including a genotype×gender interaction term. The latter was found to be nominally significant for four SNPs (rs1978340, rs3762555, rs3749034, rs2241165) in the discovery sample; of note, the respective minor/risk alleles were associated with panic disorder only in females. These findings were not confirmed in the replication sample; however, the genotype×gender interaction of rs3749034 remained significant in the combined sample. Furthermore, this polymorphism showed a nominally significant association with the Agoraphobic Cognitions Questionnaire sum score. Conclusions/Significance The present study represents the first systematic evaluation of gender-specific enrichment of risk alleles of the common SNP variation in the panic disorder candidate gene GAD1. Our tentative results provide a possible explanation for the higher susceptibility of females to panic disorder. PMID:22662185

The image variations in mastoid segment of facial nerve and sinus tympani in congenital aural atresia by HRCT and 3D VR CT.

PubMed

Wang, Zhen; Hou, Qian; Wang, Pu; Sun, Zhaoyong; Fan, Yue; Wang, Yun; Xue, Huadan; Jin, Zhengyu; Chen, Xiaowei

2015-09-01

To find the variations of middle ear structures including the spatial pattern of mastoid segment of facial nerve and the shapes of the sinus tympani in patients with congenital aural atresia (CAA) by using the high-resolution (HR) CT and 3D volume rendered (VR) CT images. HRCT was performed in 25 patients with congenital aural atresia including six bilateral atresia patients (n=25, 21 males, 4 females, mean age 13.8 years, range 6-19). Along the long axis of the posterior semicircular canal ampulla, the oblique axial multiplanar reconstruction (MPR) was set to view the depiction of the round window and the mastoid segment of facial nerve. Volumetric rending technique was used to demonstrate the morphologic features. HRCT and 3D VR findings in atresia ears were compared with those in 19 normal ears of the unilateral ears of atresia patients. On the basic plane, the horizontal line distances between the mastoid segment of the facial nerve and the round window (h-RF) in atresia ears significantly decreased compared to the control ears (P<0.05). There was a significant negative correlation between the sinus tympani area (a-ST) and the distance between the horizontal lines of FN and RW midpoint (h-RF) (P<0.05). The mean area of sinus tympani in atresia group is larger (P<0.05). The shapes of the sinus tympani were classified into three categories: the cup-shaped, the pear-shaped and the boot-shaped. Area measurement indicated that the boot-shaped sinus tympani was a special variation with a large area, which only appears in CAA group. There were a significant difference between the area of the boot-shaped group and the other two groups (P<0.05). The morphologic differences of ST and other middle ear structures can also be observed visually in 3D VR CT images. HRCT and 3D VR CT could help a better understanding of different kinds of variations in mastoid segment of facial nerve and sinus tympani in CAA ears. And it may further help surgeons to make the correct decision for hearing rehabilitation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Ethnic variations in incidence of asthma episodes in England & Wales: national study of 502,482 patients in primary care.

PubMed

Netuveli, Gopalakrishnan; Hurwitz, Brian; Sheikh, Aziz

2005-10-21

Recent studies have demonstrated marked international variations in the prevalence of asthma, but less is known about ethnic variations in asthma epidemiology within individual countries and in particular the impact of migration on risk of developing asthma. Recent within country comparisons have however revealed that despite originating from areas of the world with a low risk for developing asthma, South Asian and Afro-Caribbean people in the UK are significantly (3x and 2x respectively) more likely to be admitted to hospital for asthma related problems than Whites. Using data from the Fourth National Study of Morbidity Statistics in General Practice, a one-percent broadly representative prospective cohort study of consultations in general practice, we investigated ethnic variations in incident asthma consultations (defined as new or first consultations), and compared consultation rates between those born inside and outside the UK (migrant status). Logistic regression models were used to examine the combined effects of ethnicity and migration on asthma incident consultations. Results showed significantly lower new/first asthma consultation rates for Whites than for each of the ethnic minority groups studied (mean age-adjusted consultation rates per 1000 patient-years: Whites 26.4 (95%CI 26.4, 26.4); South Asians 30.4 (95%CI 30.3, 30.5); Afro-Caribbeans 35.1 (95%CI 34.9, 35.3); and Others 27.8 (27.7, 28.0). Within each of these ethnic groups, those born outside of the UK showed consistently lower rates of incident asthma consultations. Modelling the combined effects of ethnic and migrant status revealed that UK-born South Asians and Afro-Caribbeans experienced comparable risks for incident GP consultations for asthma to UK-born Whites. Non-UK born Whites however experienced reduced risks (adjusted OR 0.82, 95%CI 0.69, 0.97) whilst non-UK born South Asians experienced increased risks (adjusted OR 1.33, 95%CI 1.04, 1.70) compared to UK-born Whites. These findings strongly suggest that ethnicity and migration have significant and independent effects on asthma incidence. The known poorer asthma outcomes in UK South Asians and Afro-Caribbeans may in part be explained by the offspring of migrants experiencing an increased risk of developing asthma when compared to UK-born Whites. This is the first study to find heterogeneity for incident asthma consultations in Whites by migrant status.

Temporal Variation Analysis on Climate of Dry-Hot Valley Since 1950s in Upper Yangtze River Basin, China

NASA Astrophysics Data System (ADS)

Sun, L.; Cai, Y.

2017-12-01

Climate of dry-hot valley areas regarding their long term temporal changes are seldom studied. In this paper, climate change in lower reach of Yalongjiang River, a typical dry-hot valley area locating in upper Yangtze River Basin, was analyzed. Ten single meteorological factors were used to investigate basic climatic characteristics, and two integrated index (i.e. relative evapotranspiration(AET/P), standard precipitation evapotranspiration index(SPEI)) were selected to reflect changes from human activities and gauge climate drought regime. Mann-Kendall mutation test was applied to identify mutation year, and variation trends were diagnosed with linear regression and distance average analysis. Mean values were tested to find if there were significant changes resulting from a large artificial reservoir constructed in 1999. Results of mutation test showed that minimum temperature, relative humidity, and AET/P in two stations changed significantly in 2000s. Temperature increased since 1990s, and other single index fluctuated in recent 50 years. Precipitation decreased and temperature increased in autumn significantly, while precipitation in summer decreased slightly. The variation of SPEI implied that the area was humid from 1980s to 2000s, but drought in 2010s. The results of mean test indicated that 56% meteorological index changed significantly, which might be related to the construction of the large reservoir. This research not only reveals the climate change in a dry-hot valley, but also helps study concerning human activities especially the construction of cascade reservoirs in the future in this area.

Variations in the correlation between teleconnections and Taiwan's streamflow

NASA Astrophysics Data System (ADS)

Chen, Chia-Jeng; Lee, Tsung-Yu

2017-07-01

Interannual variations in catchment streamflow represent an integrated response to anomalies in regional moisture transport and atmospheric circulations and are ultimately linked to large-scale climate oscillations. This study conducts correlation analysis to calculate how summertime (July-September, JAS) streamflow data derived at 28 upstream and 13 downstream gauges in Taiwan correlate with 14 teleconnection indices in the current or preceding seasons. We find that the western Pacific (WP) and Pacific-Japan (PJ) patterns, both of which play a critical role in determining cyclonic activity in the western North Pacific basin, exhibit the highest concurrent correlations (most significant r = 0. 50) with the JAS flows in Taiwan. Alternatively, the Quasi-Biennial Oscillation (QBO) averaged over the period from the previous October to June of the current year is significantly correlated with the JAS flows (most significant r = -0. 66), indicating some forecasting utility. By further examining the correlation results using a 20-year moving window, peculiar temporal variations and possible climate regime shifts (CRSs) can be revealed. A CRS test is employed to identify suspicious and abrupt changes in the correlation. The late 1970s and 1990s are identified as two significant change points. During the intermediate period, Taiwan's streamflow and the PJ index exhibit a marked in-phase relationship (r > 0. 8). It is verified that the two shifts are in concordance with the alteration of large-scale circulations in the Pacific basin by investigating the changes in pattern correlation and composite maps before and after the change point. Our results suggest that empirical forecasting techniques should take into account the effect of CRSs on predictor screening.

Hematological variations at rest and during maximal and submaximal exercise in a cold (0°C) environment

NASA Astrophysics Data System (ADS)

Vogelaere, P.; Brasseur, M.; Quirion, A.; Leclercq, R.; Laurencelle, L.; Bekaert, S.

1990-03-01

The affect of negative thermal stress on hematological variables at rest, and during submaximal (sub ex) and maximal exercise (max ex) were observed for young males who volunteered in two experimental sessions, performed in cold (0°C) and in normal room temperature (20°C). At rest, hematological variables such as RBC and derivates Hb and Hct were significantly increased ( P<0.05) during cold stress exposure, while plasma volume decreased. The findings of this study suggest that the major factor inducing hypovolemia during low thermal stress can be imputed to local plasma water-shift mechanisms and especially to a transient shift of plasma water from intrato extravascular compartments. Rest values for WBC and platelets (Pla) were also slightly increased during cold stress exposure. However this increase can partly be related to hemoconcentration but also to the cold induced hyperventilation activating the lung circulation. Maximal exhaustive exercise induced, in both experimental temperatures, significant ( P<0.05) increments of RBC, Hb, Hct, and WBC while plasma volume decreased. However, Pla increase was less marked. On the other hand, cold stress raised slightly the observed variations of the different hematological variables. Submaximal exercise induced a similar, though non-significant, pattern for the different hematological variables in both experimental conditions. Observed plasma volume (Δ PV%) reduction appears during exercise. However cold stress induced resting plasma volume variations that are transferred at every exercise level. Neither exercise nor cold inducement significantly modified the hematological indices (MCH, MCV, MCHC). In conclusion hematological variables are affected by cold stress exposure, even when subjects perform a physical activity.

The association between male infertility and sperm disomy: Evidence for variation in disomy levels among individuals and a correlation between particular semen parameters and disomy of specific chromosome pairs

PubMed Central

Tempest, Helen G; Homa, Sheryl T; Dalakiouridou, Maria; Christopikou, Dimitra; Wright, David; Zhai, Xiao P; Griffin, Darren K

2004-01-01

Background The association between infertility and sperm disomy is well documented. Results vary but most report that men with severely compromised semen parameters have a significantly elevated proportion of disomic sperm. The relationship between individual semen parameters and segregation of specific chromosome pairs is however less well reported as is the variation of disomy levels in individual men. Methods In order to address these questions the technique of fluorescent in-situ hybridisation (FISH) was utilised to determine the disomy levels of chromosomes X, Y and 21 in 43 sperm samples from 19 infertile males. The results generated from this study were analysed using logistic regression. Results In this study we compared levels of sperm concentration, motility and morphology with levels of sperm disomy for chromosome 21 and the sex chromosomes. Our results suggest that there is considerable variation in disomy levels for certain men. They also suggest that oligozoospermic males have significantly elevated levels of sex chromosome disomy but not disomy 21; they suggest that severe asthenozoospermic males have significantly elevated levels of disomy 21 but not sex chromosome disomy. Surprisingly, severe teratozoopsermic males appeared to have significantly lower levels of sperm disomy for both the sex chromosomes and chromosome 21. Conclusion We suggest that the association between sex chromosome disomy and oligozoospermia may be due to reduced recombination in the XY pairing region and discuss the relevance of our findings for the correlations between sperm disomy and sperm motility and morphology. PMID:15598347

The association between male infertility and sperm disomy: evidence for variation in disomy levels among individuals and a correlation between particular semen parameters and disomy of specific chromosome pairs.

PubMed

Tempest, Helen G; Homa, Sheryl T; Dalakiouridou, Maria; Christopikou, Dimitra; Wright, David; Zhai, Xiao P; Griffin, Darren K

2004-12-14

The association between infertility and sperm disomy is well documented. Results vary but most report that men with severely compromised semen parameters have a significantly elevated proportion of disomic sperm. The relationship between individual semen parameters and segregation of specific chromosome pairs is however less well reported as is the variation of disomy levels in individual men. In order to address these questions the technique of fluorescent in-situ hybridisation (FISH) was utilised to determine the disomy levels of chromosomes X, Y and 21 in 43 sperm samples from 19 infertile males. The results generated from this study were analysed using logistic regression. In this study we compared levels of sperm concentration, motility and morphology with levels of sperm disomy for chromosome 21 and the sex chromosomes. Our results suggest that there is considerable variation in disomy levels for certain men. They also suggest that oligozoospermic males have significantly elevated levels of sex chromosome disomy but not disomy 21; they suggest that severe asthenozoospermic males have significantly elevated levels of disomy 21 but not sex chromosome disomy. Surprisingly, severe teratozoopsermic males appeared to have significantly lower levels of sperm disomy for both the sex chromosomes and chromosome 21. We suggest that the association between sex chromosome disomy and oligozoospermia may be due to reduced recombination in the XY pairing region and discuss the relevance of our findings for the correlations between sperm disomy and sperm motility and morphology.

Mental rotation task in a pilot during and after pregnancy.

PubMed

Piccardi, Laura; Verde, Paola; Bianchini, Filippo; Morgagni, Fabio; Guariglia, Cecilia; Strollo, Felice

2013-10-01

Discordant findings have been reported about the change in pregnant women's cognitive test performance. Visuo-spatial abilities, which are crucial in terrestrial/flight navigation, could be influenced by hormonal variations. A 32-yr-old Italian Air Force pilot underwent a 2-D Mental Rotation Task (MRT) and hormonal assessment in the second trimester of pregnancy and 1 yr after delivery. Her performance was compared with that of two nonpregnant groups of women: one with flying experience and the other without. Estradiol and progesterone were significantly higher in pregnancy compared with postpartum, while testosterone was almost unchanged. During pregnancy, we observed a significant difference in the subject's response time compared with pilots (she was slower) and nonpilots (she was faster). One year after delivery, her performance was still better than the nonpilot group and was almost the same as the pilot group. Our data are consistent with an effect of pregnancy on visuo-spatial ability that can last for some time after delivery, even with the early recovery of the hormonal levels. MRT smoothly changed in our subject, supporting previous findings that women who are experts in flight navigation are less sensitive to hormonal fluctuations. In this case, visuospatial ability requiring effortful processing underwent variations during pregnancy and postpartum. Further studies are needed in order to confirm our observations in a wider population.

Breakfast skipping in prepubertal obese children: hormonal, metabolic and cognitive consequences.

PubMed

Maffeis, C; Fornari, E; Surano, M G; Comencini, E; Corradi, M; Tommasi, M; Fasan, I; Cortese, S

2012-03-01

Skipping breakfast influences cognitive performance. The aim of our study was to investigate the relationship between the variation of hormonal and metabolic postprandial parameters induced by breakfast consumption or fasting and cognitive performance in obese children. Cross-sectional study for repeated measures. Memory and attention assessment tests, hormones and nutrient oxidation were measured before and after consuming breakfast vs fasting in 10 prepubertal obese children. Fasting induced a significant (P<0.05) increase of the Overall Index of the Continuous Performance Test II (a global index of inattention) and the Test of Memory and Learning Word Selective Reminding (a test of verbal memory), whereas no changes were found after breakfast. Fasting was associated with a reduction of insulin and an increase in glucagon, with no changes in glucose. The increase in inattention was associated with a reduction of carbohydrate oxidation (ρ=-0.66, P<0.05). We found no difference in the area under the curve of peptide YY and glucagon-like peptide-1 after breakfast or fasting, whereas Ghrelin was significantly lower. No association between postprandial hormone variation and cognitive performance was found. Attention and visual memory performance in the morning were reduced when the children skipped breakfast. No association was found with hormones or metabolic changes, but we did find an association with a reduction of carbohydrate oxidation. Nevertheless, these preliminary findings need confirmation in larger sample size.

Alpha-1-antichymotrypsin (ACT or SERPINA3) polymorphism may affect age-at-onset and disease duration of Alzheimer's disease.

PubMed

Kamboh, M Ilyas; Minster, Ryan L; Kenney, Margaret; Ozturk, Ayla; Desai, Purnima P; Kammerer, Candace M; DeKosky, Steven T

2006-10-01

In addition to genetic effects on disease risk, age-at-onset (AAO) of Alzheimer's disease (AD) is also genetically controlled. Using AAO as a covariate, a linkage signal for AD has been detected on chromosome 14q32 near the alpha1-antichymotrypsin (ACT) gene. Previously, a signal peptide polymorphism (codon -17A>T) in the ACT gene has been suggested to affect AD risk, but with inconsistent findings. Given that a linkage signal for AAO has been detected near ACT, we hypothesized that ACT genetic variation affects AAO rather than disease risk and this may explain the previous inconsistent findings between ACT genetic variation and AD risk. We examined the impact of the ACT signal peptide polymorphism on mean AAO in 909 AD cases. The ACT polymorphism was significantly associated with AAO and this effect was independent of the APOE polymorphism. Mean AAO among ACT/AA homozygotes was significantly lower than that in the combined AT+TT genotype group (p = 0.019) and this difference was confined to male AD patients (p = 0.002). Among male AD patients, the ACT/AA genotype was also associated with shorter disease duration before death as compared to the ACT/AT+TT genotypes (p = 0.012). These data suggest that the ACT gene may affect AAO and disease duration of AD.

Alpha-1-antichymotrypsin (ACT or SERPINA3) polymorphism may affect age-at-onset and disease duration of Alzheimer’s disease

PubMed Central

Kamboh, M. Ilyas; Minster, Ryan L.; Kenney, Margaret; Ozturk, Ayla; Desai, Purnima P.; Kammerer, Candace M.; DeKosky, Steven T.

2006-01-01

In addition to genetic effects on disease risk, age-at-onset (AAO) of Alzheimer’s disease (AD) is also genetically controlled. Using AAO as a covariate, a linkage signal for AD has been detected on chromosome 14q32 near the a1-antichymotrypsin (ACT) gene. Previously, a signal peptide polymorphism (codon -17A>T) in the ACT gene has been suggested to affect AD risk, but with inconsistent findings. Given that a linkage signal for AAO has been detected near ACT, we hypothesized that ACT genetic variation affects AAO rather than disease risk and this may explain the previous inconsistent findings between ACT genetic variation and AD risk. We examined the impact of the ACT signal peptide polymorphism on mean AAO in 909 AD cases. The ACT polymorphism was significantly associated with AAO and this effect was independent of the APOE polymorphism. Mean AAO among ACT/AA homozygotes was significantly lower than that in the combined AT+TT genotype group (p=0.019) and this difference was confined to male AD patients (p=0.002). Among male AD patients, the ACT/AA genotype was also associated with shorter disease duration before death as compared to the ACT/AT + TT genotypes (p=0.012). These data suggest that the ACT gene may affect AAO and disease duration of AD. PMID:16137793

Heterogeneity in the determinants of health and illness: the example of socioeconomic status and smoking.

PubMed

Birch, S; Jerrett, M; Eyles, J

2000-07-01

Systematic variations in health and illness among social groups have persisted and, in some cases increased, in many countries in spite of improvements in the availability of, and access to, health care services. Health policy makers have responded by showing increasing interest in non-clinical determinants of health as a way of explaining the observed systematic variations in health and illness. Yet health care and non-health care "factors" are often seen as competing for society's scarce resources in the production of health. The purpose of this paper is to augment this traditional approach to understanding the determinants of health in populations by exploring heterogeneity in the smoking-health relationship between social groups. Logistic regression analyses were performed using data from the 1992-93 Santé Quebéc survey, a weighted random sample of the non-institutionalized population of the province of Québec, Canada (N = 23,564). The findings suggest that the likelihood of reporting health as poor or fair was greater for smokers than non-smokers. However, the difference between smokers and non-smokers was significantly greater among groups of the population with low incomes and without employment, but significantly less among sub-groups with lower levels of education. These findings suggest that the identification, evaluation and implementation of health care programmes need to pay greater attention to the interface between social, behavioural and clinical determinants of health.

Natural variation in chemosensation: lessons from an island nematode

PubMed Central

McGaughran, Angela; Morgan, Katy; Sommer, Ralf J

2013-01-01

All organisms must interact with their environment, responding in behavioral, chemical, and other ways to various stimuli throughout their life cycles. Characterizing traits that directly represent an organism's ability to sense and react to their environment provides useful insight into the evolution of life-history strategies. One such trait for the nematode Pristionchus pacificus, chemosensation, is involved in navigation to beetle hosts. Essential for the survival of the nematode, chemosensory behavior may be subject to variation as nematodes discriminate among chemical cues to complete their life cycle. We examine this hypothesis using natural isolates of P. pacificus from La Réunion Island. We select strains from a variety of La Réunion beetle hosts and geographic locations and examine their chemoattraction response toward organic compounds, beetle washes, and live beetles. We find that nematodes show significant differences in their response to various chemicals and are able to chemotax to live beetles in a novel assay. Further, strains can discriminate among different cues, showing more similar responses toward beetle washes than to organic compounds in cluster analyses. However, we find that variance in chemoattraction response is not significantly associated with temperature, location, or beetle host. Rather, strains show a more concerted response toward compounds they most likely directly encounter in the wild. We suggest that divergence in odor-guided behavior in P. pacificus may therefore have an important ecological component. PMID:24455150

Roles of climate, vegetation and soil in regulating the spatial variations in ecosystem carbon dioxide fluxes in the Northern Hemisphere.

PubMed

Chen, Zhi; Yu, Guirui; Ge, Jianping; Wang, Qiufeng; Zhu, Xianjin; Xu, Zhiwei

2015-01-01

Climate, vegetation, and soil characteristics play important roles in regulating the spatial variation in carbon dioxide fluxes, but their relative influence is still uncertain. In this study, we compiled data from 241 eddy covariance flux sites in the Northern Hemisphere and used Classification and Regression Trees and Redundancy Analysis to assess how climate, vegetation, and soil affect the spatial variations in three carbon dioxide fluxes (annual gross primary production (AGPP), annual ecosystem respiration (ARE), and annual net ecosystem production (ANEP)). Our results showed that the spatial variations in AGPP, ARE, and ANEP were significantly related to the climate and vegetation factors (correlation coefficients, R = 0.22 to 0.69, P < 0.01) while they were not related to the soil factors (R = -0.11 to 0.14, P > 0.05) in the Northern Hemisphere. The climate and vegetation together explained 60% and 58% of the spatial variations in AGPP and ARE, respectively. Climate factors (mean annual temperature and precipitation) could account for 45-47% of the spatial variations in AGPP and ARE, but the climate constraint on the vegetation index explained approximately 75%. Our findings suggest that climate factors affect the spatial variations in AGPP and ARE mainly by regulating vegetation properties, while soil factors exert a minor effect. To more accurately assess global carbon balance and predict ecosystem responses to climate change, these discrepant roles of climate, vegetation, and soil are required to be fully considered in the future land surface models. Moreover, our results showed that climate and vegetation factors failed to capture the spatial variation in ANEP and suggest that to reveal the underlying mechanism for variation in ANEP, taking into account the effects of other factors (such as climate change and disturbances) is necessary.

Roles of Climate, Vegetation and Soil in Regulating the Spatial Variations in Ecosystem Carbon Dioxide Fluxes in the Northern Hemisphere

PubMed Central

Chen, Zhi; Yu, Guirui; Ge, Jianping; Wang, Qiufeng; Zhu, Xianjin; Xu, Zhiwei

2015-01-01

Climate, vegetation, and soil characteristics play important roles in regulating the spatial variation in carbon dioxide fluxes, but their relative influence is still uncertain. In this study, we compiled data from 241 eddy covariance flux sites in the Northern Hemisphere and used Classification and Regression Trees and Redundancy Analysis to assess how climate, vegetation, and soil affect the spatial variations in three carbon dioxide fluxes (annual gross primary production (AGPP), annual ecosystem respiration (ARE), and annual net ecosystem production (ANEP)). Our results showed that the spatial variations in AGPP, ARE, and ANEP were significantly related to the climate and vegetation factors (correlation coefficients, R = 0.22 to 0.69, P < 0.01) while they were not related to the soil factors (R = -0.11 to 0.14, P > 0.05) in the Northern Hemisphere. The climate and vegetation together explained 60 % and 58 % of the spatial variations in AGPP and ARE, respectively. Climate factors (mean annual temperature and precipitation) could account for 45 - 47 % of the spatial variations in AGPP and ARE, but the climate constraint on the vegetation index explained approximately 75 %. Our findings suggest that climate factors affect the spatial variations in AGPP and ARE mainly by regulating vegetation properties, while soil factors exert a minor effect. To more accurately assess global carbon balance and predict ecosystem responses to climate change, these discrepant roles of climate, vegetation, and soil are required to be fully considered in the future land surface models. Moreover, our results showed that climate and vegetation factors failed to capture the spatial variation in ANEP and suggest that to reveal the underlying mechanism for variation in ANEP, taking into account the effects of other factors (such as climate change and disturbances) is necessary. PMID:25928452

Extent and variations in mobile phone use among drivers of heavy vehicles in Denmark.

PubMed

Troglauer, Thomas; Hels, Tove; Christens, Peter Falck

2006-01-01

A substantial body of research has shown that use of mobile phones while driving can impair driving performance and increase the risk of being involved in accidents. Similarly, mobile phone use seems to be an increasing activity thus representing a relevant traffic safety issue. This paper investigates the extent and variations in mobile phone use among drivers of heavy vehicles in Denmark. The data was collected through written questionnaires and had a response rate of 58%. It was found that more than 99% of the drivers used mobile phones while driving. Despite a prohibition of hand-held mobile phone use while driving 31% of the drivers reported to do so. Analysis of the variations in usage found a positive significant relationship between driving hours and phone use. A negative linear effect was found between age and phone use. Similarly, a positive significant association was found between the number of stops and the amount of phone use. 0.5% reported that their use of mobile phones had contributed to an accident, while 6% had experienced their mobile phone use causing a dangerous situation. However, 66% reported experiencing dangerous situations because of others road users' mobile phone use. Various implications of the findings are discussed particularly in relation to the drivers with high exposure.

Intraspecific variation in growth of marsh macrophytes in response to salinity and soil type: Implications for wetland restoration

USGS Publications Warehouse

Howard, R.J.

2010-01-01

Genetic diversity within plant populations can influence plant community structure along environmental gradients. In wetland habitats, salinity and soil type are factors that can vary along gradients and therefore affect plant growth. To test for intraspecific growth variation in response to these factors, a greenhouse study was conducted using common plants that occur in northern Gulf of Mexico brackish and salt marshes. Individual plants of Distichlis spicata, Phragmites australis, Schoenoplectus californicus, and Schoenoplectus robustus were collected from several locations along the coast in Louisiana, USA. Plant identity, based on collection location, was used as a measure of intraspecific variability. Prepared soil mixtures were organic, silt, or clay, and salinity treatments were 0 or 18 psu. Significant intraspecific variation in stem number, total stem height, or biomass was found in all species. Within species, response to soil type varied, but increased salinity significantly decreased growth in all individuals. Findings indicate that inclusion of multiple genets within species is an important consideration for marsh restoration projects that include vegetation plantings. This strategy will facilitate establishment of plant communities that have the flexibility to adapt to changing environmental conditions and, therefore, are capable of persisting over time. ?? Coastal and Estuarine Research Federation 2009.

Transcriptomic and metabolomic profiles of Chinese citrus fly, Bactrocera minax (Diptera: Tephritidae), along with pupal development provide insight into diapause program

PubMed Central

Fan, Huan; Xiong, Ke-Cai; Liu, Ying-Hong

2017-01-01

The Chinese citrus fly, Bactrocera minax (Enderlein), is a devastating citrus pest in Asia. This univoltine insect enters obligatory pupal diapause in each generation, while little is known about the course and the molecular mechanisms of diapause. In this study, the course of diapause was determined by measuring the respiratory rate throughout the pupal stage. In addition, the variation of transcriptomic and metabolomic profiles of pupae at five developmental stages (pre-, early-, middle-, late-, and post-diapause) were evaluated by next-generation sequencing technology and 1H nuclear magnetic resonance spectroscopy (NMR), respectively. A total of 4,808 genes were significantly altered in ten pairwise comparisons, representing major shifts in metabolism and signal transduction as well as endocrine system and digestive system. Gene expression profiles were validated by qRT-PCR analysis. In addition, 48 metabolites were identified and quantified by 1H NMR. Nine of which significantly contributed to the variation in the metabolomic profiles, especially proline and trehalose. Moreover, the samples collected within diapause maintenance (early-, middle-, and late-diapause) only exhibited marginal transcriptomic and metabolomic variation with each other. These findings greatly improve our understanding of B. minax diapause and lay the foundation for further pertinent studies. PMID:28704500

Tolerance to environmental desiccation in moss sperm.

PubMed

Shortlidge, Erin E; Rosenstiel, Todd N; Eppley, Sarah M

2012-05-01

• Sexual reproduction in mosses requires that sperm be released freely into the environment before finding and fertilizing a receptive female. After release from the male plant, moss sperm may experience a range of abiotic stresses; however, few data are available examining stress tolerance of moss sperm and whether there is genetic variation for stress tolerance in this important life stage. • Here, we investigated the effects of environmental desiccation and recovery on the sperm cells of three moss species (Bryum argenteum, Campylopus introflexus, and Ceratodon purpureus). • We found that a fraction of sperm cells were tolerant to environmental desiccation for extended periods (d) and that tolerance did not vary among species. We found that this tolerance occurs irrespective of ambient dehydration conditions, and that the addition of sucrose during dry-down improved cell recovery. Although we observed no interspecific variation, significant variation among individuals within species in sperm cell tolerance to environmental desiccation was observed, suggesting selection could potentially act on this basic reproductive trait. • The observation of desiccation-tolerant sperm in multiple moss species has important implications for understanding bryophyte reproduction, suggesting the presence of a significant, uncharacterized complexity in the ecology of moss mating systems. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Marker-Based Estimates Reveal Significant Non-additive Effects in Clonally Propagated Cassava (Manihot esculenta): Implications for the Prediction of Total Genetic Value and the Selection of Varieties.

PubMed

Wolfe, Marnin D; Kulakow, Peter; Rabbi, Ismail Y; Jannink, Jean-Luc

2016-08-31

In clonally propagated crops, non-additive genetic effects can be effectively exploited by the identification of superior genetic individuals as varieties. Cassava (Manihot esculenta Crantz) is a clonally propagated staple food crop that feeds hundreds of millions. We quantified the amount and nature of non-additive genetic variation for three key traits in a breeding population of cassava from sub-Saharan Africa using additive and non-additive genome-wide marker-based relationship matrices. We then assessed the accuracy of genomic prediction for total (additive plus non-additive) genetic value. We confirmed previous findings based on diallel populations, that non-additive genetic variation is significant for key cassava traits. Specifically, we found that dominance is particularly important for root yield and epistasis contributes strongly to variation in CMD resistance. Further, we showed that total genetic value predicted observed phenotypes more accurately than additive only models for root yield but not for dry matter content, which is mostly additive or for CMD resistance, which has high narrow-sense heritability. We address the implication of these results for cassava breeding and put our work in the context of previous results in cassava, and other plant and animal species. Copyright © 2016 Author et al.

Natural Variation of Model Mutant Phenotypes in Ciona intestinalis

PubMed Central

Brown, Euan R.; Leccia, Nicola I.; Squarzoni, Paola; Tarallo, Raffaella; Alfano, Christian; Caputi, Luigi; D'Ambrosio, Palmira; Daniele, Paola; D'Aniello, Enrico; D'Aniello, Salvatore; Maiella, Sylvie; Miraglia, Valentina; Russo, Monia Teresa; Sorrenti, Gerarda; Branno, Margherita; Cariello, Lucio; Cirino, Paola; Locascio, Annamaria; Spagnuolo, Antonietta; Zanetti, Laura; Ristoratore, Filomena

2008-01-01

Background The study of ascidians (Chordata, Tunicata) has made a considerable contribution to our understanding of the origin and evolution of basal chordates. To provide further information to support forward genetics in Ciona intestinalis, we used a combination of natural variation and neutral population genetics as an approach for the systematic identification of new mutations. In addition to the significance of developmental variation for phenotype-driven studies, this approach can encompass important implications in evolutionary and population biology. Methodology/Principal Findings Here, we report a preliminary survey for naturally occurring mutations in three geographically interconnected populations of C. intestinalis. The influence of historical, geographical and environmental factors on the distribution of abnormal phenotypes was assessed by means of 12 microsatellites. We identified 37 possible mutant loci with stereotyped defects in embryonic development that segregate in a way typical of recessive alleles. Local populations were found to differ in genetic organization and frequency distribution of phenotypic classes. Conclusions/Significance Natural genetic polymorphism of C. intestinalis constitutes a valuable source of phenotypes for studying embryonic development in ascidians. Correlating genetic structure and the occurrence of abnormal phenotypes is a crucial focus for understanding the selective forces that shape natural finite populations, and may provide insights of great importance into the evolutionary mechanisms that generate animal diversity. PMID:18523552

Simultaneous Monitoring of X-ray and Radio Variability in Sagittarius A*

NASA Astrophysics Data System (ADS)

Haggard, Daryl; Capellupo, Daniel M.; Choux, Nicolas; Baganoff, Frederick K.; Bower, Geoffrey C.; Cotton, William D.; Degenaar, Nathalie; Dexter, Jason; Falcke, Heino; Fragile, P. Christopher Christopher; Heinke, Craig O.; Law, Casey J.; Markoff, Sera; Neilsen, Joseph; Ponti, Gabriele; Rea, Nanda; Yusef-Zadeh, Farhad

2017-08-01

We report on joint X-ray/radio campaigns targeting Sagittarius A*, including 9 contemporaneous Chandra and VLA observations. These campaigns are the most extensive of their kind and have allowed us to test whether the black hole’s variations in different parts of the electromagnetic spectrum are due to the same physical processes. We detect significant radio variability peaking >176 minutes after the brightest X-ray flare ever detected from Sgr A*. We also identify other potentially associated X-ray and radio variability, with radio peaks appearing <80 minutes after weaker X-ray flares. These results suggest that stronger X-ray flares lead to longer time lags in the radio. However, we also test the possibility that the variability at X-ray and at radio wavelengths are not temporally correlated, and show that the radio variations occurring around the time of X-ray flaring are not significantly greater than the overall radio flux variations. We also cross-correlate data from mismatched X-ray and radio epochs and obtain comparable correlations to the matched data. Hence, we find no overall statistical evidence that X-ray flares and radio variability are correlated, underscoring a need for more simultaneous, long duration X-ray-radio monitoring of Sgr A*.

Semiquantitative color profiling of soils over a land degradation gradient in Sakaerat, Thailand.

PubMed

Doi, Ryoichi; Wachrinrat, Chongrak; Teejuntuk, Sakhan; Sakurai, Katsutoshi; Sahunalu, Pongsak

2010-11-01

In this study, we attempted multivariate color profiling of soils over a land degradation gradient represented by dry evergreen forest (original vegetation), dry deciduous forest (moderately disturbed by fire), and bare ground (severely degraded) in Sakaerat, Thailand. The soils were sampled in a dry-to-wet seasonal transition. Values of the red-green-blue (RGB), cyan-magenta-yellow-key black (CMYK), L*a*b*, and hue-intensity-saturation (HIS) color models were determined using the digital software Adobe Photoshop. Land degradation produced significant variations (p<0.05) in R, C, Y, L*, a*, b*, S, and I values (p<0.05). The seasonal transition produced significant variations (p<0.05) in R, G, B, C, M, K, L*, b*, and I values. In discriminating the soils, the color models did not differ in discriminatory power, while discriminatory power was affected by seasonal changes. Most color variation patterns had nonlinear relationships with the intensity of the land degradation gradient, due to effects of fire that darkened the deciduous forest soil, masking the nature of the soil as the intermediate between the evergreen forest and the bare ground soils. Taking these findings into account, the utilization of color profiling of soils in land conservation and rehabilitation is discussed.

Some regional variations in dietary patterns in a random sample of British adults.

PubMed

Whichelow, M J; Erzinclioglu, S W; Cox, B D

1991-05-01

Comparison was made of the reported frequency of consumption or choice of 30 food items by 8860 adults in the 11 standard regions of Great Britain, with the use of log-linear analysis to allow for the age, sex, social class and smoking habit variations between the regions. The South-East was taken as the base region against which the others were compared. The number of food items for which there were significant differences from the South-East were Scotland 23, North 25, North-West and Yorkshire/Humberside 20, Wales 19, West Midlands 15, East Midlands 10, East Anglia 8, South-West 7 and Greater London 9. Overall the findings confirm a North/South trend in relation to eating habits, even when demographic and smoking-habit variations are taken into account, with the frequent consumption of many fruit and vegetable products being much less common and of several high-fat foods (chips, processed meats and fried food) more common in Scotland, Wales and the northern part of England. In most regions there was a significantly lower frequency of consumption of fresh fruit, fruit juice, 'brown' bread, pasta/rice, poultry, skimmed/semi-skimmed milk, light desserts and nuts, and a higher consumption of red meat, fish and fried food than in the South-East.

Polymorphisms in the Wilms Tumor Gene Are Associated With Interindividual Variations in Rubella Virus-Specific Cellular Immunity After Measles-Mumps-Rubella II Vaccination.

PubMed

Voigt, Emily A; Haralambieva, Iana H; Larrabee, Beth L; Kennedy, Richard B; Ovsyannikova, Inna G; Schaid, Daniel J; Poland, Gregory A

2018-01-30

Rubella vaccination induces widely variable immune responses in vaccine recipients. While rubella vaccination is effective at inducing immunity to rubella infection in most subjects, up to 5% of individuals do not achieve or maintain long-term protective immunity. To expand upon our previous work identifying genetic polymorphisms that are associated with these interindividual differences in humoral immunity to rubella virus, we performed a genome-wide association study in a large cohort of 1843 subjects to discover single-nucleotide polymorphisms (SNPs) associated with rubella virus-specific cellular immune responses. We identified SNPs in the Wilms tumor protein gene (WT1) that were significantly associated (P < 5 × 10-8) with interindividual variations in rubella-specific interleukin 6 secretion from subjects' peripheral blood mononuclear cells postvaccination. No SNPs were found to be significantly associated with variations in rubella-specific interferon-γ secretion. Our findings demonstrate that genetic polymorphisms in the WT1 gene in subjects of European ancestry are associated with interindividual differences in rubella virus-specific cellular immunity after measles-mumps-rubella II vaccination. © The Author(s) 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Effects of capillary heterogeneity on vapor-liquid counterflow in porous media

NASA Astrophysics Data System (ADS)

Stubos, A. K.; Satik, C.; Yortsos, Y. C.

1992-06-01

Based on a continuum description, the effect of capillary heterogeneity, induced by variation in permeability, on the steady state, countercurrent, vapor-liquid flow in porous media is analyzed. It is shown that the heterogeneity acts as a body force that may enhance or diminish gravity effects on heat pipes. Selection rules that determine the steady states reached in homogeneous, gravity-driven heat pipes are also formulated. It is shown that the 'infinite' two-phase zone may terminate by a substantial change in the permeability somewhere in the medium. The two possible sequences, liquid-liquid dominated-dry, or liquid-vapor dominated-dry find applications in geothermal systems. Finally, it is shown that although weak heterogeneity affects only gravity controlled flows, stronger variations in permeability can give rise to significant capillary effects.

Fluency variation in adolescents.

PubMed

Furquim de Andrade, Claudia Regina; de Oliveira Martins, Vanessa

2007-10-01

The Speech Fluency Profile of fluent adolescent speakers of Brazilian Portuguese, were examined with respect to gender and neurolinguistic variations. Speech samples of 130 male and female adolescents, aged between 12;0 and 17;11 years were gathered. They were analysed according to type of speech disruption; speech rate; and frequency of speech disruptions. Statistical analysis did not find significant differences between genders for the variables studied. However, regarding the phases of adolescence (early: 12;0-14;11 years; late: 15;0-17;11 years), statistical differences were observed for all of the variables. As for neurolinguistic maturation, a decrease in the number of speech disruptions and an increase in speech rate occurred during the final phase of adolescence, indicating that the maturation of the motor and linguistic processes exerted an influence over the fluency profile of speech.

Climate induces seasonality in pneumococcal transmission

PubMed Central

Numminen, Elina; Chewapreecha, Claire; Turner, Claudia; Goldblatt, David; Nosten, Francois; Bentley, Stephen D.; Turner, Paul; Corander, Jukka

2015-01-01

Streptococcus pneumoniae is a significant human pathogen and a leading cause of infant mortality in developing countries. Considerable global variation in the pneumococcal carriage prevalence has been observed and the ecological factors contributing to it are not yet fully understood. We use data from a cohort of infants in Asia to study the effects of climatic conditions on both acquisition and clearance rates of the bacterium, finding significantly higher transmissibility during the cooler and drier months. Conversely, the length of a colonization period is unaffected by the season. Independent carriage data from studies conducted on the African and North American continents suggest similar effects of the climate on the prevalence of this bacterium, which further validates the obtained results. Further studies could be important to replicate the findings and explain the mechanistic role of cooler and dry air in the physiological response to nasopharyngeal acquisition of the pneumococcus. PMID:26067932

The Future of Health Care Reform: What Is Driving Enrollment?

PubMed

Callaghan, Timothy H; Jacobs, Lawrence R

2017-04-01

Against a backdrop of ongoing operational challenges, insurance market turbulence, and the ever present pull of partisanship, enrollment in the ACA's programs has soared and significant variations have developed across states in terms of their pace of coverage expansion. Our article explores why ACA enrollment has varied so dramatically across states. We explore the potential influence of party control, presidential cueing, administrative capacity, the reverberating effects of ACA policy decisions, affluence, and unemployment on enrollment. Our multivariate analysis finds that party control dominated early state decision making, but that relative enrollment in insurance exchanges and the Medicaid expansion are driven by a changing mix of political and administrative factors. Health politics is entering a new era as Republicans replace the ACA and devolve significant discretion to states to administer Medicaid and other programs. Our findings offer insights into future directions in health reform and in learning and diffusion. Copyright © 2017 by Duke University Press.

Climate induces seasonality in pneumococcal transmission.

PubMed

Numminen, Elina; Chewapreecha, Claire; Turner, Claudia; Goldblatt, David; Nosten, Francois; Bentley, Stephen D; Turner, Paul; Corander, Jukka

2015-06-12

Streptococcus pneumoniae is a significant human pathogen and a leading cause of infant mortality in developing countries. Considerable global variation in the pneumococcal carriage prevalence has been observed and the ecological factors contributing to it are not yet fully understood. We use data from a cohort of infants in Asia to study the effects of climatic conditions on both acquisition and clearance rates of the bacterium, finding significantly higher transmissibility during the cooler and drier months. Conversely, the length of a colonization period is unaffected by the season. Independent carriage data from studies conducted on the African and North American continents suggest similar effects of the climate on the prevalence of this bacterium, which further validates the obtained results. Further studies could be important to replicate the findings and explain the mechanistic role of cooler and dry air in the physiological response to nasopharyngeal acquisition of the pneumococcus.

G-Protein Genomic Association With Normal Variation in Gray Matter Density

PubMed Central

Chen, Jiayu; Calhoun, Vince D.; Arias-Vasquez, Alejandro; Zwiers, Marcel P.; van Hulzen, Kimm; Fernández, Guillén; Fisher, Simon E.; Franke, Barbara; Turner, Jessica A.; Liu, Jingyu

2017-01-01

While detecting genetic variations underlying brain structures helps reveal mechanisms of neural disorders, high data dimensionality poses a major challenge for imaging genomic association studies. In this work, we present the application of a recently proposed approach, parallel independent component analysis with reference (pICA-R), to investigate genomic factors potentially regulating gray matter variation in a healthy population. This approach simultaneously assesses many variables for an aggregate effect and helps to elicit particular features in the data. We applied pICA-R to analyze gray matter density (GMD) images (274,131 voxels) in conjunction with single nucleotide polymorphism (SNP) data (666,019 markers) collected from 1,256 healthy individuals of the Brain Imaging Genetics (BIG) study. Guided by a genetic reference derived from the gene GNA14, pICA-R identified a significant SNP-GMD association (r = −0.16, P = 2.34 × 10−8), implying that subjects with specific genotypes have lower localized GMD. The identified components were then projected to an independent dataset from the Mind Clinical Imaging Consortium (MCIC) including 89 healthy individuals, and the obtained loadings again yielded a significant SNP-GMD association (r = −0.25, P = 0.02). The imaging component reflected GMD variations in frontal, precuneus, and cingulate regions. The SNP component was enriched in genes with neuronal functions, including synaptic plasticity, axon guidance, molecular signal transduction via PKA and CREB, highlighting the GRM1, PRKCH, GNA12, and CAMK2B genes. Collectively, our findings suggest that GNA12 and GNA14 play a key role in the genetic architecture underlying normal GMD variation in frontal and parietal regions. PMID:26248772

Genet-specific DNA methylation probabilities detected in a spatial epigenetic analysis of a clonal plant population.

PubMed

Araki, Kiwako S; Kubo, Takuya; Kudoh, Hiroshi

2017-01-01

In sessile organisms such as plants, spatial genetic structures of populations show long-lasting patterns. These structures have been analyzed across diverse taxa to understand the processes that determine the genetic makeup of organismal populations. For many sessile organisms that mainly propagate via clonal spread, epigenetic status can vary between clonal individuals in the absence of genetic changes. However, fewer previous studies have explored the epigenetic properties in comparison to the genetic properties of natural plant populations. Here, we report the simultaneous evaluation of the spatial structure of genetic and epigenetic variation in a natural population of the clonal plant Cardamine leucantha. We applied a hierarchical Bayesian model to evaluate the effects of membership of a genet (a group of individuals clonally derived from a single seed) and vegetation cover on the epigenetic variation between ramets (clonal plants that are physiologically independent individuals). We sampled 332 ramets in a 20 m × 20 m study plot that contained 137 genets (identified using eight SSR markers). We detected epigenetic variation in DNA methylation at 24 methylation-sensitive amplified fragment length polymorphism (MS-AFLP) loci. There were significant genet effects at all 24 MS-AFLP loci in the distribution of subepiloci. Vegetation cover had no statistically significant effect on variation in the majority of MS-AFLP loci. The spatial aggregation of epigenetic variation is therefore largely explained by the aggregation of ramets that belong to the same genets. By applying hierarchical Bayesian analyses, we successfully identified a number of genet-specific changes in epigenetic status within a natural plant population in a complex context, where genotypes and environmental factors are unevenly distributed. This finding suggests that it requires further studies on the spatial epigenetic structure of natural populations of diverse organisms, particularly for sessile clonal species.

Inter-Ethnic/Racial Facial Variations: A Systematic Review and Bayesian Meta-Analysis of Photogrammetric Studies

PubMed Central

Wen, Yi Feng; Wong, Hai Ming; Lin, Ruitao; Yin, Guosheng; McGrath, Colman

2015-01-01

Background Numerous facial photogrammetric studies have been published around the world. We aimed to critically review these studies so as to establish population norms for various angular and linear facial measurements; and to determine inter-ethnic/racial facial variations. Methods and Findings A comprehensive and systematic search of PubMed, ISI Web of Science, Embase, and Scopus was conducted to identify facial photogrammetric studies published before December, 2014. Subjects of eligible studies were either Africans, Asians or Caucasians. A Bayesian hierarchical random effects model was developed to estimate posterior means and 95% credible intervals (CrI) for each measurement by ethnicity/race. Linear contrasts were constructed to explore inter-ethnic/racial facial variations. We identified 38 eligible studies reporting 11 angular and 18 linear facial measurements. Risk of bias of the studies ranged from 0.06 to 0.66. At the significance level of 0.05, African males were found to have smaller nasofrontal angle (posterior mean difference: 8.1°, 95% CrI: 2.2°–13.5°) compared to Caucasian males and larger nasofacial angle (7.4°, 0.1°–13.2°) compared to Asian males. Nasolabial angle was more obtuse in Caucasian females than in African (17.4°, 0.2°–35.3°) and Asian (9.1°, 0.4°–17.3°) females. Additional inter-ethnic/racial variations were revealed when the level of statistical significance was set at 0.10. Conclusions A comprehensive database for angular and linear facial measurements was established from existing studies using the statistical model and inter-ethnic/racial variations of facial features were observed. The results have implications for clinical practice and highlight the need and value for high quality photogrammetric studies. PMID:26247212

Normal variation in sagittal spinal alignment parameters in adult patients: an EOS study using serial imaging.

PubMed

Hey, Hwee Weng Dennis; Tan, Kian Loong Melvin; Moorthy, Vikaesh; Lau, Eugene Tze-Chun; Lau, Leok-Lim; Liu, Gabriel; Wong, Hee-Kit

2018-03-01

To describe normal variations in sagittal spinal radiographic parameters over an interval period and establish physiological norms and guidelines for which these images should be interpreted. Data were prospectively collected from a continuous series of adult patients with first-episode mild low back pain presenting to a single institution. The sagittal parameters of two serial radiographic images taken 6-months apart were obtained with the EOS ® slot scanner. Measured parameters include CL, TK, TL, LL, PI, PT, SS, and end and apical vertebrae. Chi-squared test and Wilcoxon Signed Rank test were used to compare categorical and continuous variables, respectively. Sixty patients with a total of 120 whole-body sagittal X-rays were analysed. Mean age was 52.1 years (SD 21.2). Mean interval between the first and second X-rays was 126.2 days (SD 47.2). Small variations (< 1°) occur for all except PT (1.2°), CL (1.2°), and SVA (2.9 cm). Pelvic tilt showed significant difference between two images (p = 0.035). Subgroup analysis based on the time interval between X-rays, and between the first and second X-rays, did not show significant differences. Consistent findings were found for end and apical vertebrae of the thoracic and lumbar spine between the first and second X-rays for sagittal curve shapes. Radiographic sagittal parameters vary between serial images and reflect dynamism in spinal balancing. SVA and PT are predisposed to the widest variation. SVA has the largest variation between individuals of low pelvic tilt. Therefore, interpretation of these parameters should be patient specific and relies on trends rather than a one-time assessment.

Pedigree- and SNP-Associated Genetics and Recent Environment are the Major Contributors to Anthropometric and Cardiometabolic Trait Variation.

PubMed

Xia, Charley; Amador, Carmen; Huffman, Jennifer; Trochet, Holly; Campbell, Archie; Porteous, David; Hastie, Nicholas D; Hayward, Caroline; Vitart, Veronique; Navarro, Pau; Haley, Chris S

2016-02-01

Genome-wide association studies have successfully identified thousands of loci for a range of human complex traits and diseases. The proportion of phenotypic variance explained by significant associations is, however, limited. Given the same dense SNP panels, mixed model analyses capture a greater proportion of phenotypic variance than single SNP analyses but the total is generally still less than the genetic variance estimated from pedigree studies. Combining information from pedigree relationships and SNPs, we examined 16 complex anthropometric and cardiometabolic traits in a Scottish family-based cohort comprising up to 20,000 individuals genotyped for ~520,000 common autosomal SNPs. The inclusion of related individuals provides the opportunity to also estimate the genetic variance associated with pedigree as well as the effects of common family environment. Trait variation was partitioned into SNP-associated and pedigree-associated genetic variation, shared nuclear family environment, shared couple (partner) environment and shared full-sibling environment. Results demonstrate that trait heritabilities vary widely but, on average across traits, SNP-associated and pedigree-associated genetic effects each explain around half the genetic variance. For most traits the recently-shared environment of couples is also significant, accounting for ~11% of the phenotypic variance on average. On the other hand, the environment shared largely in the past by members of a nuclear family or by full-siblings, has a more limited impact. Our findings point to appropriate models to use in future studies as pedigree-associated genetic effects and couple environmental effects have seldom been taken into account in genotype-based analyses. Appropriate description of the trait variation could help understand causes of intra-individual variation and in the detection of contributing loci and environmental factors.

A multi-wavelength search for photometric variability in L dwarfs

NASA Astrophysics Data System (ADS)

Gelino, Christopher Ryan

Previous studies investigating L-dwarf variability have been conducted in the optical I filter. These studies have shown that some, but not all L dwarfs are variable in this filter. In this dissertation I increase the number of L dwarfs observed for variations in the I filter from 10 to 25, with another three from the original ten reexamined here. I find that at least 7 and possibly as many as 12 are variable. One of these variable objects has a puzzling saw-tooth pattern in part of its light curve and another displays a feature that could indicate the creation and dissipation of a large storm. There is no evidence for significant differences between the variable and non- variable objects in their colors, Hα emission, or Li I absorption. I argue that the lack of a correlation between Hα and variability, coupled with low magnetic Reynolds number and ionization fraction in the upper atmosphere, suggests a non-magnetic origin for the variations and favors non-uniform condensate coverage. Furthermore, the absence of significant periodicity in these objects could indicate that these clouds evolve rapidly on timescales of hours to days. In addition to the optical survey, I also present the first multi-wavelength near-infrared search for photometric variations in L dwarfs. I was unable to detect any definite variability in these eleven targets. The upper limits for the amplitude of possible variations suggest that L dwarfs display smaller variations in K than in J and H . The small number of objects on which this conclusion is based and the lack of variability detections underscores the importance of more work in this wavelength regime.

Effects of posted point-of-sale warnings on alcohol consumption during pregnancy and on birth outcomes.

PubMed

Cil, Gulcan

2017-05-01

In 23 states and Washington D.C., alcohol retailers are required by law to post alcohol warning signs (AWS) that warn against the risks of drinking during pregnancy. Using the variation in the adoption of these laws across states and within states over time, I find a statistically significant reduction in prenatal alcohol use associated with AWS. I then use this plausibly exogenous change in drinking behavior to establish a causal link between prenatal alcohol exposure and birth outcomes. I find that AWS laws are associated with decreases in the odds of very low birth weight and very pre-term birth. Copyright © 2017 Elsevier B.V. All rights reserved.

SNP-based heritability estimates of the personality dimensions and polygenic prediction of both neuroticism and major depression: findings from CONVERGE.

PubMed

Docherty, A R; Moscati, A; Peterson, R; Edwards, A C; Adkins, D E; Bacanu, S A; Bigdeli, T B; Webb, B T; Flint, J; Kendler, K S

2016-10-25

Biometrical genetic studies suggest that the personality dimensions, including neuroticism, are moderately heritable (~0.4 to 0.6). Quantitative analyses that aggregate the effects of many common variants have recently further informed genetic research on European samples. However, there has been limited research to date on non-European populations. This study examined the personality dimensions in a large sample of Han Chinese descent (N=10 064) from the China, Oxford, and VCU Experimental Research on Genetic Epidemiology study, aimed at identifying genetic risk factors for recurrent major depression among a rigorously ascertained cohort. Heritability of neuroticism as measured by the Eysenck Personality Questionnaire (EPQ) was estimated to be low but statistically significant at 10% (s.e.=0.03, P=0.0001). In addition to EPQ, neuroticism based on a three-factor model, data for the Big Five (BF) personality dimensions (neuroticism, openness, conscientiousness, extraversion and agreeableness) measured by the Big Five Inventory were available for controls (n=5596). Heritability estimates of the BF were not statistically significant despite high power (>0.85) to detect heritabilities of 0.10. Polygenic risk scores constructed by best linear unbiased prediction weights applied to split-half samples failed to significantly predict any of the personality traits, but polygenic risk for neuroticism, calculated with LDpred and based on predictive variants previously identified from European populations (N=171 911), significantly predicted major depressive disorder case-control status (P=0.0004) after false discovery rate correction. The scores also significantly predicted EPQ neuroticism (P=6.3 × 10 -6 ). Factor analytic results of the measures indicated that any differences in heritabilities across samples may be due to genetic variation or variation in haplotype structure between samples, rather than measurement non-invariance. Findings demonstrate that neuroticism can be significantly predicted across ancestry, and highlight the importance of studying polygenic contributions to personality in non-European populations.

Association between in vivo alcohol metabolism and genetic variation in pathways that metabolize the carbon skeleton of ethanol and NADH reoxidation in the Alcohol Challenge Twin Study

PubMed Central

Lind, Penelope A; Macgregor, Stuart; Heath, Andrew C; Madden, Pamela AF; Montgomery, Grant W; Martin, Nicholas G; Whitfield, John B

2013-01-01

Background Variation in alcohol metabolism affects the duration of intoxication and alcohol use. While the majority of genetic association studies investigating variation in alcohol metabolism have focused on polymorphisms in alcohol or aldehyde dehydrogenases, we have now tested for association with genes in alternative metabolic pathways that catalyze the carbon skeleton of ethanol and NADH reoxidation. Methods 950 single nucleotide polymorphisms (SNPs) spanning 14 genes (ACN9, ACSS1, ACSS2, ALDH1A1, CAT, CYP2E1, GOT1, GOT2, MDH1, MDH2, SLC25A10, SLC25A11, SLC25A12, SLC25A13) were genotyped in 352 young adults who participated in an alcohol challenge study. Traits tested were blood and breath alcohol concentration, peak alcohol concentration and rates of alcohol absorption and elimination. Allelic association was tested using quantitative univariate and multivariate methods. Results A CYP2E1 promoter SNP (rs4838767, minor allele frequency 0.008) exceeded the threshold for study-wide significance (4.01 × 10−5) for two early blood alcohol concentration (BAC), eight breath alcohol concentration (BrAC) measures and the peak BrAC. For each phenotype the minor C-allele was related to a lower alcohol concentration, most strongly for the fourth BrAC (P = 2.07 × 10−7) explaining ~8% of the phenotypic variance. We also observed suggestive patterns of association with variants in ALDH1A1 and on chromosome 17 near SLC25A11 for aspects of blood and breath alcohol metabolism. A SNP upstream of GOT1 (rs2490286) reached study-wide significance for multivariate BAC metabolism (P = 0.000040). Conclusions Overall, we did not find strong evidence that variation in genes coding for proteins that further metabolize the carbon backbone of acetaldehyde, or contribute to mechanisms for regenerating NAD from NADH, affects alcohol metabolism in our European-descent subjects. However, based on the breath alcohol data, variation in the promoter of CYP2E1 may play a role in pre-absorptive or early hepatic alcohol metabolism, but more samples are required to validate this finding. PMID:22577853

Association between in vivo alcohol metabolism and genetic variation in pathways that metabolize the carbon skeleton of ethanol and NADH reoxidation in the alcohol challenge twin study.

PubMed

Lind, Penelope A; Macgregor, Stuart; Heath, Andrew C; Madden, Pamela A F; Montgomery, Grant W; Martin, Nicholas G; Whitfield, John B

2012-12-01

Variation in alcohol metabolism affects the duration of intoxication and alcohol use. While the majority of genetic association studies investigating variation in alcohol metabolism have focused on polymorphisms in alcohol or aldehyde dehydrogenases, we have now tested for association with genes in alternative metabolic pathways that catalyze the carbon skeleton of ethanol (EtOH) and NADH reoxidation. Nine hundred fifty single nucleotide polymorphisms (SNPs) spanning 14 genes (ACN9, ACSS1, ACSS2, ALDH1A1, CAT, CYP2E1, GOT1, GOT2, MDH1, MDH2, SLC25A10, SLC25A11, SLC25A12, SLC25A13) were genotyped in 352 young adults who participated in an alcohol challenge study. Traits tested were blood alcohol concentration (BAC), breath alcohol concentration (BrAC), peak alcohol concentration, and rates of alcohol absorption and elimination. Allelic association was tested using quantitative univariate and multivariate methods. A CYP2E1 promoter SNP (rs4838767, minor allele frequency 0.008) exceeded the threshold for study-wide significance (4.01 × 10(-5) ) for 2 early BAC, 8 BrAC measures, and the peak BrAC. For each phenotype, the minor C allele was related to a lower alcohol concentration, most strongly for the fourth BrAC (p = 2.07 × 10(-7) ) explaining ~8% of the phenotypic variance. We also observed suggestive patterns of association with variants in ALDH1A1 and on chromosome 17 near SLC25A11 for aspects of blood and breath alcohol metabolism. An SNP upstream of GOT1 (rs2490286) reached study-wide significance for multivariate BAC metabolism (p = 0.000040). Overall, we did not find strong evidence that variation in genes coding for proteins that further metabolize the carbon backbone of acetaldehyde, or contribute to mechanisms for regenerating NAD from NADH, affects alcohol metabolism in our European-descent subjects. However, based on the breath alcohol data, variation in the promoter of CYP2E1 may play a role in preabsorptive or early hepatic alcohol metabolism, but more samples are required to validate this finding. Copyright © 2012 by the Research Society on Alcoholism.

Genetic Architecture of Natural Variation in Rice Nonphotochemical Quenching Capacity Revealed by Genome-Wide Association Study

PubMed Central

Wang, Quanxiu; Zhao, Hu; Jiang, Junpeng; Xu, Jiuyue; Xie, Weibo; Fu, Xiangkui; Liu, Chang; He, Yuqing; Wang, Gongwei

2017-01-01

The photoprotective processes conferred by nonphotochemical quenching (NPQ) serve fundamental roles in maintaining plant fitness and sustainable yield. So far, few loci have been reported to be involved in natural variation of NPQ capacity in rice (Oryza sativa), and the extents of variation explored are very limited. Here we conducted a genome-wide association study (GWAS) for NPQ capacity using a diverse worldwide collection of 529 O. sativa accessions. A total of 33 significant association loci were identified. To check the validity of the GWAS signals, three F2 mapping populations with parents selected from the association panel were constructed and assayed. All QTLs detected in mapping populations could correspond to at least one GWAS signal, indicating the GWAS results were quite reliable. OsPsbS1 was repeatedly detected and explained more than 40% of the variation in the whole association population in two years, and demonstrated to be a common major QTL in all three mapping populations derived from inter-group crosses. We revealed 43 single nucleotide polymorphisms (SNPs) and 7 insertions and deletions (InDels) within a 6,997-bp DNA fragment of OsPsbS1, but found no non-synonymous SNPs or InDels in the coding region, indicating the PsbS1 protein sequence is highly conserved. Haplotypes with the 2,674-bp insertion in the promoter region exhibited significantly higher NPQ values and higher expression levels of OsPsbS1. The OsPsbS1 RNAi plants and CRISPR/Cas9 mutants exhibited drastically decreased NPQ values. OsPsbS1 had specific and high-level expression in green tissues of rice. However, we didn't find significant function for OsPsbS2, the other rice PsbS homologue. Manipulation of the significant loci or candidate genes identified may enhance photoprotection and improve photosynthesis and yield in rice. PMID:29081789

Genetic Architecture of Natural Variation in Rice Nonphotochemical Quenching Capacity Revealed by Genome-Wide Association Study.

PubMed

Wang, Quanxiu; Zhao, Hu; Jiang, Junpeng; Xu, Jiuyue; Xie, Weibo; Fu, Xiangkui; Liu, Chang; He, Yuqing; Wang, Gongwei

2017-01-01

The photoprotective processes conferred by nonphotochemical quenching (NPQ) serve fundamental roles in maintaining plant fitness and sustainable yield. So far, few loci have been reported to be involved in natural variation of NPQ capacity in rice ( Oryza sativa ), and the extents of variation explored are very limited. Here we conducted a genome-wide association study (GWAS) for NPQ capacity using a diverse worldwide collection of 529 O. sativa accessions. A total of 33 significant association loci were identified. To check the validity of the GWAS signals, three F2 mapping populations with parents selected from the association panel were constructed and assayed. All QTLs detected in mapping populations could correspond to at least one GWAS signal, indicating the GWAS results were quite reliable. OsPsbS1 was repeatedly detected and explained more than 40% of the variation in the whole association population in two years, and demonstrated to be a common major QTL in all three mapping populations derived from inter-group crosses. We revealed 43 single nucleotide polymorphisms (SNPs) and 7 insertions and deletions (InDels) within a 6,997-bp DNA fragment of OsPsbS1 , but found no non-synonymous SNPs or InDels in the coding region, indicating the PsbS1 protein sequence is highly conserved. Haplotypes with the 2,674-bp insertion in the promoter region exhibited significantly higher NPQ values and higher expression levels of OsPsbS1 . The OsPsbS1 RNAi plants and CRISPR/Cas9 mutants exhibited drastically decreased NPQ values. OsPsbS1 had specific and high-level expression in green tissues of rice. However, we didn't find significant function for OsPsbS2 , the other rice PsbS homologue. Manipulation of the significant loci or candidate genes identified may enhance photoprotection and improve photosynthesis and yield in rice.

Inherited variation in circadian rhythm genes and risks of prostate cancer and three other cancer sites in combined cancer consortia.

PubMed

Gu, Fangyi; Zhang, Han; Hyland, Paula L; Berndt, Sonja; Gapstur, Susan M; Wheeler, William; Ellipse Consortium, The; Amos, Christopher I; Bezieau, Stephane; Bickeböller, Heike; Brenner, Hermann; Brennan, Paul; Chang-Claude, Jenny; Conti, David V; Doherty, Jennifer Anne; Gruber, Stephen B; Harrison, Tabitha A; Hayes, Richard B; Hoffmeister, Michael; Houlston, Richard S; Hung, Rayjean J; Jenkins, Mark A; Kraft, Peter; Lawrenson, Kate; McKay, James; Markt, Sarah; Mucci, Lorelei; Phelan, Catherine M; Qu, Conghui; Risch, Angela; Rossing, Mary Anne; Wichmann, H-Erich; Shi, Jianxin; Schernhammer, Eva; Yu, Kai; Landi, Maria Teresa; Caporaso, Neil E

2017-11-01

Circadian disruption has been linked to carcinogenesis in animal models, but the evidence in humans is inconclusive. Genetic variation in circadian rhythm genes provides a tool to investigate such associations. We examined associations of genetic variation in nine core circadian rhythm genes and six melatonin pathway genes with risk of colorectal, lung, ovarian and prostate cancers using data from the Genetic Associations and Mechanisms in Oncology (GAME-ON) network. The major results for prostate cancer were replicated in the Prostate, Lung, Colorectal and Ovarian (PLCO) cancer screening trial, and for colorectal cancer in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO). The total number of cancer cases and controls was 15,838/18,159 for colorectal, 14,818/14,227 for prostate, 12,537/17,285 for lung and 4,369/9,123 for ovary. For each cancer site, we conducted gene-based and pathway-based analyses by applying the summary-based Adaptive Rank Truncated Product method (sARTP) on the summary association statistics for each SNP within the candidate gene regions. Aggregate genetic variation in circadian rhythm and melatonin pathways were significantly associated with the risk of prostate cancer in data combining GAME-ON and PLCO, after Bonferroni correction (p pathway  < 0.00625). The two most significant genes were NPAS2 (p gene  = 0.0062) and AANAT (p gene  = 0.00078); the latter being significant after Bonferroni correction. For colorectal cancer, we observed a suggestive association with the circadian rhythm pathway in GAME-ON (p pathway  = 0.021); this association was not confirmed in GECCO (p pathway  = 0.76) or the combined data (p pathway  = 0.17). No significant association was observed for ovarian and lung cancer. These findings support a potential role for circadian rhythm and melatonin pathways in prostate carcinogenesis. Further functional studies are needed to better understand the underlying biologic mechanisms. © 2017 UICC.

Decomposing functional trait associations in a Chinese subtropical forest

PubMed Central

Pei, Kequan; Kéry, Marc; Niklaus, Pascal A.; Schmid, Bernhard

2017-01-01

Functional traits, properties of organisms correlated with ecological performance, play a central role in plant community assembly and functioning. To some extents, functional traits vary in concert, reflecting fundamental ecological strategies. While “trait syndromes” characteristic of e.g. fast-growing, early-successional vs. competitive, late-successional species are recognized in principle, less is known about the environmental and genetic factors at the source of trait variation and covariation within plant communities. We studied the three leaf traits leaf half-life (LHL), leaf mass per area (LMA) and nitrogen concentration in green leaves (Ngreen) and the wood trait wood density (WD) in 294 individuals belonging to 45 tree or shrub species in a Chinese subtropical forest from September 2006 to January 2009. Using multilevel ANOVA and decomposition of sums of products, we estimated the amount of trait variation and covariation among species (mainly genetic causes), i.e. plant functional type (deciduous vs. evergreen species), growth form (tree vs. shrub species), family/genus/species differences, and within species (mainly environmental causes), i.e. individual and season. For single traits, the variation between functional types and among species within functional types was large, but only LMA and Ngreen varied significantly among families and thus showed phylogenetic signal. Trait variation among individuals within species was small, but large temporal variation due to seasonal effects was found within individuals. We did not find any trait variation related to soil conditions underneath the measured individuals. For pairs of traits, variation between functional types and among species within functional types was large, reflecting a strong evolutionary coordination of the traits, with LMA, LHL and WD being positively correlated among each other and negatively with Ngreen. This integration of traits was consistent with a putative stem-leaf economics spectrum ranging from deciduous species with thin, high-nitrogen leaves and low-density wood to evergreen species with thick, low-nitrogen leaves and dense wood and was not influenced by phylogenetic history. Trait coordination within species was weak, allowing individual trees to deviate from the interspecific trait coordination and thus respond flexibly to environmental heterogeneity. Our findings suggest that within a single woody plant community variation and covariation in functional traits allows a large number of species to co-exist and cover a broad spectrum of multivariate niche space, which in turn may increase total resource extraction by the community and community functioning. PMID:28419169

Variations and determinants of carbon content in plants: a global synthesis

NASA Astrophysics Data System (ADS)

Ma, Suhui; He, Feng; Tian, Di; Zou, Dongting; Yan, Zhengbing; Yang, Yulong; Zhou, Tiancheng; Huang, Kaiyue; Shen, Haihua; Fang, Jingyun

2018-02-01

Plant carbon (C) content is one of the most important plant traits and is critical to the assessment of global C cycle and ecological stoichiometry; however, the global variations in plant C content remain poorly understood. In this study, we conducted a global analysis of the plant C content by synthesizing data from 4318 species to document specific values and their variation of the C content across plant organs and life forms. Plant organ C contents ranged from 45.0 % in reproductive organs to 47.9 % in stems at global scales, which were significantly lower than the widely employed canonical value of 50 %. Plant C content in leaves (global mean of 46.9 %) was higher than that in roots (45.6 %). Across life forms, woody plants exhibited higher C content than herbaceous plants. Conifers, relative to broad-leaved woody species, had higher C content in roots, leaves, and stems. Plant C content tended to show a decrease with increasing latitude. The life form explained more variation of the C content than climate. Our findings suggest that specific C content values of different organs and life forms developed in our study should be incorporated into the estimations of regional and global vegetation biomass C stocks.

Assessment of calcium and zinc accumulation in cultivated and wild apples.

PubMed

Liao, Liao; Fang, Ting; Ma, Baiquan; Deng, Xianbao; Zhao, Li; Han, Yuepeng

2017-09-01

Apple is one of the staple fruits worldwide which are a good source of mineral nutrients. However, little is known about genetic variation for mineral nutrition in apple germplasm. In this study, the calcium and zinc contents in mature fruits of 378 apple cultivars and 39 wild relatives were assessed. Mineral concentrations were quantified using flame atomic absorption spectroscopy (FAAS). Both calcium and zinc accumulation showed great variation among accessions tested. Overall, wild fruits were significantly richer in zinc than cultivated fruits, while the average concentration of calcium was similar between cultivated and wild fruits. The difference in zinc concentration between wild and cultivated fruits may be an indirect result of artificial selection on fruit characteristics during apple domestication. Moreover, calcium concentration in fruit showed a decreasing trend throughout fruit development of apple, while zinc concentration in fruit displayed a complex variation pattern in the late stages of fruit development. The finding of a wild genetic variation for fruit calcium and zinc accumulation in apple germplasm could be helpful for future research on genetic dissection and improvement of calcium and zinc accumulation in apple fruit. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Influence of ethnicity, geography and climate on the variation of stature among Indian populations.

PubMed

Bharati, Susmita; Mukherji, Dipak; Pal, Manoranjan; Som, Suparna; Kumar Adak, Dipak; Vasulu, T S; Bharati, Premananda

2010-12-01

This paper analyzes the variation in the mean stature of adult males of a variety of population groups in India and examines the influence of geographical, climatic and ethnic factors on it. A considerable variation in mean stature has been found with respect to these three attributes. Variation "between" ethnic groups compared with "within" ethnic groups was found to be much more than that of geographical and climatic zones. Scheduled Castes (SC) and Scheduled Tribes (ST) populations have much low average height than that of General Castes (GC). Climatically dry and semiarid zones have a tendency to have higher stature than in the Monsoon areas. The mean height has been found to be the highest in north India. It is closely followed by west India. An interesting feature is that as one goes towards east and south the mean height gradually decreases. It is the lowest in islands. The mean heights have been regressed on geographical, climatic and ethnic factors, after converting these factors into binary variables. The regression analysis has strengthened the findings, that there is a highly significant relationship between height and geographical, climatic and ethnic factors.

Investigating the Source of the Gender Gap in Introductory Physics

NASA Astrophysics Data System (ADS)

Kost, Lauren E.; Pollock, Steven J.; Finkelstein, Noah D.

2007-11-01

Our previous research showed that despite the use of interactive engagement (IE) techniques at our institution, the difference in performance between men and women on a conceptual learning survey persisted from pre to posttest. This paper reports on a three-part follow-up study that investigates what factors contribute to the gender gap. First, we analyze student grades in different components of the course and find that men and women's course grades are not significantly different (p>0.1), but men outscore women on exams and women outscore men on homework and participation. Second, we compare average posttest scores of men and women who score similarly on the pretest and find that there are no significant differences between men and women's average posttest scores. Finally, we analyze other factors in addition to the pretest score that could influence the posttest score and find that gender does not account for a meaningful portion of the variation in posttest scores when a measure of mathematics performance is included. These findings indicate that the gender gap exists in interactive physics classes, but may be due in large part to differences in preparation, background, and math skills as assessed by traditional survey instruments.

Multi-band, multi-epoch observations of the transiting warm Jupiter WASP-80b

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukui, Akihiko; Kuroda, Daisuke; Kawashima, Yui

WASP-80b is a warm Jupiter transiting a bright late-K/early-M dwarf, providing a good opportunity to extend the atmospheric study of hot Jupiters toward the lower temperature regime. We report multi-band, multi-epoch transit observations of WASP-80b by using three ground-based telescopes covering from optical (g', R{sub c}, and I{sub c} bands) to near-infrared (NIR; J, H, and K{sub s} bands) wavelengths. We observe 5 primary transits, each in 3 or 4 different bands simultaneously, obtaining 17 independent transit light curves. Combining them with results from previous works, we find that the observed transmission spectrum is largely consistent with both a solarmore » abundance and thick cloud atmospheric models at a 1.7σ discrepancy level. On the other hand, we find a marginal spectral rise in the optical region compared to the NIR region at the 2.9σ level, which possibly indicates the existence of haze in the atmosphere. We simulate theoretical transmission spectra for a solar abundance but hazy atmosphere, finding that a model with equilibrium temperature of 600 K can explain the observed data well, having a discrepancy level of 1.0σ. We also search for transit timing variations, but find no timing excess larger than 50 s from a linear ephemeris. In addition, we conduct 43 day long photometric monitoring of the host star in the optical bands, finding no significant variation in the stellar brightness. Combined with the fact that no spot-crossing event is observed in the five transits, our results confirm previous findings that the host star appears quiet for spot activities, despite the indications of strong chromospheric activities.« less

Understanding the importance of permanent and transitory shocks at business cycle horizons for the UK

NASA Astrophysics Data System (ADS)

Narayan, Paresh Kumar

2008-05-01

The goal of this paper is to examine the relative importance of permanent and transitory shocks in explaining variations in macroeconomic aggregates for the UK at business cycle horizons. Using the common trend-common cycle restrictions, we estimate a variance decomposition of shocks, and find that over short horizons the bulk of the variations in income and consumption were due to permanent shocks while transitory shocks explain the bulk of the variations in investment. Our findings for income and consumption are consistent with real business cycle models which emphasize the role of aggregate supply shocks, while our findings for investment are consistent with the Keynesian school of thought, which emphasizes the role of aggregate demand shocks in explaining business cycles.

Identification of human plasma metabolites exhibiting time-of-day variation using an untargeted liquid chromatography-mass spectrometry metabolomic approach.

PubMed

Ang, Joo Ern; Revell, Victoria; Mann, Anuska; Mäntele, Simone; Otway, Daniella T; Johnston, Jonathan D; Thumser, Alfred E; Skene, Debra J; Raynaud, Florence

2012-08-01

Although daily rhythms regulate multiple aspects of human physiology, rhythmic control of the metabolome remains poorly understood. The primary objective of this proof-of-concept study was identification of metabolites in human plasma that exhibit significant 24-h variation. This was assessed via an untargeted metabolomic approach using liquid chromatography-mass spectrometry (LC-MS). Eight lean, healthy, and unmedicated men, mean age 53.6 (SD ± 6.0) yrs, maintained a fixed sleep/wake schedule and dietary regime for 1 wk at home prior to an adaptation night and followed by a 25-h experimental session in the laboratory where the light/dark cycle, sleep/wake, posture, and calorific intake were strictly controlled. Plasma samples from each individual at selected time points were prepared using liquid-phase extraction followed by reverse-phase LC coupled to quadrupole time-of-flight MS analysis in positive ionization mode. Time-of-day variation in the metabolites was screened for using orthogonal partial least square discrimination between selected time points of 10:00 vs. 22:00 h, 16:00 vs. 04:00 h, and 07:00 (d 1) vs. 16:00 h, as well as repeated-measures analysis of variance with time as an independent variable. Subsequently, cosinor analysis was performed on all the sampled time points across the 24-h day to assess for significant daily variation. In this study, analytical variability, assessed using known internal standards, was low with coefficients of variation <10%. A total of 1069 metabolite features were detected and 203 (19%) showed significant time-of-day variation. Of these, 34 metabolites were identified using a combination of accurate mass, tandem MS, and online database searches. These metabolites include corticosteroids, bilirubin, amino acids, acylcarnitines, and phospholipids; of note, the magnitude of the 24-h variation of these identified metabolites was large, with the mean ratio of oscillation range over MESOR (24-h time series mean) of 65% (95% confidence interval [CI]: 49-81%). Importantly, several of these human plasma metabolites, including specific acylcarnitines and phospholipids, were hitherto not known to be 24-h variant. These findings represent an important baseline and will be useful in guiding the design and interpretation of future metabolite-based studies.

Variation in osteocyte lacunar morphology and density in the human femur - a synchrotron radiation micro-CT study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, Yasmin; Thomas, C David L.; Clement, John G

2013-04-09

In recent years there has been growing interest in the spatial properties of osteocytes (including density and morphology) and how these potentially relate to adaptation, disease and aging. This interest has, in part, arisen from the availability of increasingly high-resolution 3D imaging modalities such as synchrotron radiation (SR) micro-CT. As resolution increases, field of view generally decreases. Thus, while increasingly detailed spatial information is obtained, it is unclear how representative this information is of the skeleton or even the isolated bone. The purpose of this research was to describe the variation in osteocyte lacunar density, morphology and orientation within themore » femur from a healthy young male human. Multiple anterior, posterior, medial and lateral blocks (2 mm × 2 mm) were prepared from the proximal femoral shaft and SR micro-CT imaged at the Advanced Photon Source. Average lacunar densities (± standard deviation) from the anterior, posterior, medial and lateral regions were 27,169 ± 1935, 26,3643 ± 1262, 37,521 ± 6416 and 33,972 ± 2513 lacunae per mm 3 of bone tissue, respectively. These values were significantly different between the medial and both the anterior and posterior regions (p < 0.05). The density of the combined anterior and posterior regions was also significantly lower (p = 0.001) than the density of the combined medial and lateral regions. Although no difference was found in predominant orientation, shape differences were found; with the combined anterior and posterior regions having more elongated (p = 0.004) and flattened (p = 0.045) lacunae, than those of the medial and lateral regions. This study reveals variation in osteocyte lacunar density and morphology within the cross-section of a single bone and that this variation can be considerable (up to 30% difference in density between regions). The underlying functional significance of the observed variation in lacunar density likely relates to localized variations in loading conditions as the pattern corresponds well with mechanical axes. Lower density and more elongate shapes being associated with the antero-posterior oriented neutral axis. Our findings demonstrate that the functional and pathological interpretations that are increasingly being drawn from high resolution imaging of osteocyte lacunae need to be better situated within the broader context of normal variation, including that which occurs even within a single skeletal element.« less

Swallow Event Sequencing: Comparing Healthy Older and Younger Adults.

PubMed

Herzberg, Erica G; Lazarus, Cathy L; Steele, Catriona M; Molfenter, Sonja M

2018-04-23

Previous research has established that a great deal of variation exists in the temporal sequence of swallowing events for healthy adults. Yet, the impact of aging on swallow event sequence is not well understood. Kendall et al. (Dysphagia 18(2):85-91, 2003) suggested there are 4 obligatory paired-event sequences in swallowing. We directly compared adherence to these sequences, as well as event latencies, and quantified the percentage of unique sequences in two samples of healthy adults: young (< 45) and old (> 65). The 8 swallowing events that contribute to the sequences were reliably identified from videofluoroscopy in a sample of 23 healthy seniors (10 male, mean age 74.7) and 20 healthy young adults (10 male, mean age 31.5) with no evidence of penetration-aspiration or post-swallow residue. Chi-square analyses compared the proportions of obligatory pairs and unique sequences by age group. Compared to the older subjects, younger subjects had significantly lower adherence to two obligatory sequences: Upper Esophageal Sphincter (UES) opening occurs before (or simultaneous with) the bolus arriving at the UES and UES maximum distention occurs before maximum pharyngeal constriction. The associated latencies were significantly different between age groups as well. Further, significantly fewer unique swallow sequences were observed in the older group (61%) compared with the young (82%) (χ 2  = 31.8; p < 0.001). Our findings suggest that paired swallow event sequences may not be robust across the age continuum and that variation in swallow sequences appears to decrease with aging. These findings provide normative references for comparisons to older individuals with dysphagia.

Trace lithium is inversely associated with male suicide after adjustment of climatic factors.

PubMed

Shiotsuki, Ippei; Terao, Takeshi; Ishii, Nobuyoshi; Takeuchi, Shouhei; Kuroda, Yoshiki; Kohno, Kentaro; Mizokami, Yoshinori; Hatano, Koji; Tanabe, Sanshi; Kanehisa, Masayuki; Iwata, Noboru; Matusda, Shinya

2016-01-01

Previously, we showed the inverse association between lithium in drinking water and male suicide in Kyushu Island. The narrow variation in meteorological factors of Kyushu Island and a considerable amount of evidence regarding the role of the factors on suicide provoked the necessities of adjusting the association by the wide variation in sunshine, temperature, rain fall, and snow fall. To keep the wide variation in meteorological factors, we combined the data of Kyushu (the southernmost city is Itoman, 26°) and Hokkaido (the northernmost city is Wakkanai, 45°). Multiple regression analyses were used to predict suicide SMRs (total, male and female) by lithium levels in drinking water and meteorological factors. After adjustment of meteorological factors, lithium levels were significantly and inversely associated with male suicide SMRs, but not with total or female suicide SMRs, across the 153 cities of Hokkaido and Kyushu Islands. Moreover, annual total sunshine and annual mean temperature were significantly and inversely associated with male suicide SMRs whereas annual total rainfall was significantly and directly associated with male suicide SMRs. The limitations of the present study include the lack of data relevant to lithium levels in food and the proportion of the population who drank tap water and their consumption habits. The present findings suggest that trace lithium is inversely associated with male but not female suicide after adjustment of meteorological factors. Copyright © 2015 Elsevier B.V. All rights reserved.

Practice Variations in the Management of Inflammatory Bowel Disease Between Pediatric and Adult Gastroenterologists.

PubMed

Assa, Amit; Avni, Irit; Ben-Bassat, Ofer; Niv, Yaron; Shamir, Raanan

2016-03-01

Different practice guidelines and consensus statements for both pediatric- and adult-onset inflammatory bowel disease exist. Although variations in medical care among gastroenterologists are common, it is unknown whether there are fundamental differences between disciplines. The primary aim of the present study was to investigate differences in common practices across disciplines. This was a prospective, questionnaire-based survey of gastroenterologists attending gastroenterology meetings in Israel. The questionnaire covered attitudes to medical resources, diagnostic and follow-up measures as well as therapeutic approaches. Overall, 120 (60%) of the approached adult gastroenterologists (AGs) and 49 (75%) pediatric gastroenterologists (PGs) completed the questionnaire. The 2 groups differed significantly in various practice areas. Pediatric patients are seen more frequently and for longer appointments. PGs tend to assess thiopurine metabolites (96% vs 47%) more often during treatment. There is a significant variation in practice between groups concerning infectious serology status and vaccinations. Methotrexate in Crohn patients is used more commonly by PGs (55% vs 22%). Long-term combination therapy of thiopurines and anti-tumor necrosis factorα agents is used more often by AGs. In patients with ulcerative colitis AGs use oral 5-aminosalicylic acid once daily (51% vs 21%) and add rectal agents from the first day of treatment (72% vs 35%) more often as compared with PGs. This study demonstrates that common practices in inflammatory bowel disease patients differ significantly between adult and pediatric practitioners. These findings call for investigating the reasons for these differences and promoting strategies to diminish these gaps.

Variability at the FCGR locus: characterization in Black South Africans and evidence for ethnic variation in and out of Africa.

PubMed

Lassaunière, R; Tiemessen, C T

2016-03-01

This study set out to comprehensively investigate all known functional FcγR variants in South African Black and Caucasian individuals. Population diversity was further assessed using data from the 1000 Genomes Project. In our cohort, Black South Africans neither possessed the haplotypes previously associated with increased surface densities of FcγRIIb and FcγRIIIa nor the FCGR2C haplotype recently associated with increased vaccine efficacy in the RV144 HIV-1 vaccine trial (despite 48.7% bearing the c.134-96T tag allele). Moreover, Africans (South Africans, Luhya Kenyans and Yoruba Nigerians) lack the FCGR2C c.798+1G splice-site allele required for the expression of functional FcγRIIc. Although the presence or absence of surface FcγRIIc did not affect natural killer cell-mediated antibody-dependent cellular cytotoxicity capability, this may be significant for other FcγRIIc-mediated functions. Overall, allele distribution and linkage disequilibrium in Africans and Caucasians differed in a manner that would suggest a differentially maintained balance of FcγR-mediated cell activation in these populations. Finally, significant variation observed among different African populations precludes the use of any one African population as a proxy for FcγR diversity in Africans. In conclusion, the findings of this study highlight further ethnic variation at the FCGR gene locus, in particular for FCGR2C, a gene with increasingly recognized clinical significance.

[Variation of satellite-based spring vegetation phenology and the relationship with climate in the Northern Hemisphere over 1982 to 2009.

PubMed

Cong, Nan; Shen, Miao Gen

2016-09-01

In-depth understanding the variation of vegetation spring phenology is important and nece-ssary for estimation and prediction of ecosystem response to climate change. Satellite-based estimation is one of the important methods for detecting the vegetation spring phenology in Northern Hemisphere. However, there are still many uncertainties among different remote sensing models. In this study, we employed NDVI satellite product from 1982 to 2009 to estimate vegetation green-up onset dates in spring across Northern Hemisphere, and further analyzed the phenology spatio-temporal variation and the relationship with climate. Results showed that spatial mean spring phenology significantly advanced by (4.0±0.8) days during this period in the Northern Hemisphere, while spring phenology advanced much faster in Eurasia (0.22±0.04 d·a -1 ) than in North America (0.03±0.02 d·a -1 ). Moreover, phenology of different vegetation types changed inconstantly during the period. All five methods consistently indicated that grassland significantly advanced, while forests didn't advance robustly among methods. In addition, the interannual change of spring phenology was mainly driven by spring temperature. The spring phenology advanced (3.2±0.5) days with 1 ℃ increase in temperature. On the contrary, we did not find significant relationship between vegetation spring phenology and spring accumulative precipitation across the Northern Hemisphere (P>0.05) in this study.

The effect of flower position on variation and covariation in floral traits in a wild hermaphrodite plant

PubMed Central

2010-01-01

Background Floral traits within plants can vary with flower position or flowering time. Within an inflorescence, sexual allocation of early produced basal flowers is often female-biased while later produced distal flowers are male-biased. Such temporal adjustment of floral resource has been considered one of the potential advantages of modularity (regarding a flower as a module) in hermaphrodites. However, flowers are under constraints of independent evolution of a given trait. To understand flower diversification within inflorescences, here we examine variation and covariation in floral traits within racemes at the individual and the maternal family level respectively in an alpine herb Aconitum gymnandrum (Ranunculaceae). Results We found that floral traits varied significantly with flower position and among families, and position effects were family-specific. Most of the variance of floral traits was among individuals rather than among flowers within individuals or among families. Significant phenotypic correlations between traits were not affected by position, indicating trait integration under shared developmental regulation. In contrast, positive family-mean correlations in floral traits declined gradually from basal to distal flowers (nine significant correlations among floral traits in basal flowers and only three in distal flowers), showing position-specificity. Therefore, the pattern and magnitude of genetic correlations decreased with flower position. Conclusions This finding on covariation pattern in floral reproductive structures within racemes has not been revealed before, providing insights into temporal variation and position effects in floral traits within plants and the potential advantages of modularity in hermaphrodites. PMID:20482889

The effect of flower position on variation and covariation in floral traits in a wild hermaphrodite plant.

PubMed

Zhao, Zhi-Gang; Du, Guo-Zhen; Huang, Shuang-Quan

2010-05-20

Floral traits within plants can vary with flower position or flowering time. Within an inflorescence, sexual allocation of early produced basal flowers is often female-biased while later produced distal flowers are male-biased. Such temporal adjustment of floral resource has been considered one of the potential advantages of modularity (regarding a flower as a module) in hermaphrodites. However, flowers are under constraints of independent evolution of a given trait. To understand flower diversification within inflorescences, here we examine variation and covariation in floral traits within racemes at the individual and the maternal family level respectively in an alpine herb Aconitum gymnandrum (Ranunculaceae). We found that floral traits varied significantly with flower position and among families, and position effects were family-specific. Most of the variance of floral traits was among individuals rather than among flowers within individuals or among families. Significant phenotypic correlations between traits were not affected by position, indicating trait integration under shared developmental regulation. In contrast, positive family-mean correlations in floral traits declined gradually from basal to distal flowers (nine significant correlations among floral traits in basal flowers and only three in distal flowers), showing position-specificity. Therefore, the pattern and magnitude of genetic correlations decreased with flower position. This finding on covariation pattern in floral reproductive structures within racemes has not been revealed before, providing insights into temporal variation and position effects in floral traits within plants and the potential advantages of modularity in hermaphrodites.

Understanding the Gender Gap in Introductory Physics

NASA Astrophysics Data System (ADS)

Finkelstein, Noah; Kost, Lauren; Pollock, Steven

2008-04-01

While it has been suggested interactive engagement (IE) techniques can eliminate the gender gap (the difference in performance between men and women on measures of conceptual learning), we find that, at our institution, the gender gap persisted from pre to posttest in IE classes (Pollock, Physical Review: ST PER. 3, 010107, 2007). This talk reports on a three-part follow-up study that investigates what factors contribute to the gender gap. First, we analyze student grades in different components of the course and find that men and women's course grades are not significantly different (p>0.1), but men outscore women on exams and women outscore men on homework and participation. Second, we compare average posttest scores of men and women who score similarly on the pretest and find that there are no significant differences between men and women's average posttest scores. Finally, we analyze other factors in addition to the pretest score that could influence the posttest score and find that gender does not account for a majorportion of the variation in posttest scores when a measure of mathematics performance is included. These findings indicate that the gender gap exists in interactive physics classes, but may be due in large part to differences in preparation, background, and math skills as assessed by traditional survey instruments.

NoSOCS in SDSS - VI. The environmental dependence of AGN in clusters and field in the local Universe

NASA Astrophysics Data System (ADS)

Lopes, P. A. A.; Ribeiro, A. L. B.; Rembold, S. B.

2017-11-01

We investigated the variation in the fraction of optical active galactic nuclei (AGNs) hosts with stellar mass, as well as their local and global environments. Our sample is composed of cluster members and field galaxies at z ≤ 0.1 and we consider only strong AGN. We find a strong variation in the AGN fraction (FAGN) with stellar mass. The field population comprises a higher AGN fraction compared to the global cluster population, especially for objects with log M* > 10.6. Hence, we restricted our analysis to more massive objects. We detected a smooth variation in the FAGN with local stellar mass density for cluster objects, reaching a plateau in the field environment. As a function of cluster-centric distance we verify that FAGN is roughly constant for R > R200, but show a steep decline inwards. We have also verified the dependence of the AGN population on cluster velocity dispersion, finding a constant behaviour for low mass systems (σP ≲ 650-700 km s-1). However, there is a strong decline in FAGN for higher mass clusters (>700 km s-1). When comparing the FAGN in clusters with or without substructure, we only find different results for objects at large radii (R > R200), in the sense that clusters with substructure present some excess in the AGN fraction. Finally, we have found that the phase-space distribution of AGN cluster members is significantly different than other populations. Due to the environmental dependence of FAGN and their phase-space distribution, we interpret AGN to be the result of galaxy interactions, favoured in environments where the relative velocities are low, typical of the field, low mass groups or cluster outskirts.

Audit of radiology communication systems for critical, urgent, and unexpected significant findings.

PubMed

Duncan, K A; Drinkwater, K J; Dugar, N; Howlett, D C

2016-03-01

To determine the compliance of UK radiology departments and trusts/healthcare organisations with National Patient Safety Agency and Royal College of Radiologist's published guidance on the communication of critical, urgent, and unexpected significant radiological findings. A questionnaire was sent to all UK radiology department audit leads asking for details of their current departmental policy regarding the issuing of alerts; use of automated electronic alert systems; methods of notification of clinicians of critical, urgent, and unexpected significant radiological findings; monitoring of results receipt; and examples of the more common types of serious pathologies for which alerts were issued. One hundred and fifty-four of 229 departments (67%) responded. Eighty-eight percent indicated that they had a policy in place for the communication of critical, urgent, and unexpected significant radiological findings. Only 34% had an automated electronic alert system in place and only 17% had a facility for service-wide electronic tracking of radiology reports. In only 11 departments with an electronic acknowledgement system was someone regularly monitoring the read rate. There is wide variation in practice across the UK with regard to the communication and monitoring of reports with many departments/trusts not fully compliant with published UK guidance. Despite the widespread use of electronic systems, only a minority of departments/trusts have and use electronic tracking to ensure reports have been read and acted upon. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

An Experimental and Numerical Comparison of the Rupture Locations of an Abdominal Aortic Aneurysm

PubMed Central

Doyle, Barry J.; Corbett, Timothy J.; Callanan, Anthony; Walsh, Michael T.; Vorp, David A.; McGloughlin, Timothy M.

2009-01-01

Purpose: To identify the rupture locations of idealized physical models of abdominal aortic aneurysm (AAA) using an in-vitro setup and to compare the findings to those predicted numerically. Methods: Five idealized AAAs were manufactured using Sylgard 184 silicone rubber, which had been mechanically characterized from tensile tests, tear tests, and finite element analysis. The models were then inflated to the point of rupture and recorded using a high-speed camera. Numerical modeling attempted to confirm these rupture locations. Regional variations in wall thickness of the silicone models was also quantified and applied to numerical models. Results: Four of the 5 models tested ruptured at inflection points in the proximal and distal regions of the aneurysm sac and not at regions of maximum diameter. These findings agree with high stress regions computed numerically. Wall stress appears to be independent of wall thickness, with high stress occurring at regions of inflection regardless of wall thickness variations. Conclusion: According to these experimental and numerical findings, AAAs experience higher stresses at regions of inflection compared to regions of maximum diameter. Ruptures of the idealized silicone models occurred predominantly at the inflection points, as numerically predicted. Regions of inflection can be easily identified from basic 3-dimensional reconstruction; as ruptures appear to occur at inflection points, these findings may provide a useful insight into the clinical significance of inflection regions. This approach will be applied to patient-specific models in a future study. PMID:19642790

Suicide and general elections in Austria: do preceding regional suicide rate differentials foreshadow subsequent voting behavior swings?

PubMed

Voracek, Martin; Formann, Anton K; Fülöp, Gerhard; Sonneck, Gernot

2003-05-01

Suicide-epidemiological research on short-term effects of elections on national/regional suicide and parasuicide incidence has yielded contradictory evidence. Reversing the cause-effect relationship of this line of research we investigated whether preceding regional suicide rates are related to subsequent election results. For Austria's 121 districts, we regressed averaged standardized suicide rates for the preceding period (1988-1994) on political parties' subsequent electoral gains/losses (1999-to-1995) while controlling for a set of 12 domain-relevant psychosocial/economic indices. Stepwise weighted multiple regression led to a significant model. The 1999-to-1995 electoral gains/losses of two opposition parties, together with the population variation caused by migration balance and by births/deaths balance, accounted for a substantial part (30%) of the variability in preceding district-level suicide rates. Various other social indices failed to contribute further substantial increments to this model. This finding suggests that variations in preceding regional suicide incidence might be mirrored in subsequent changes in voting behavior. A speculative post hoc explanation for the finding is offered: on a community level, suicide's aftermath might produce socially and politically alienated survivors of suicide who co-shape swings towards opposition parties in subsequent general elections. The finding calls for more research on suicide's long-term aftermath. Within-country replicability and cross-national generalizability await further investigation. At present, the factor/mechanism accounting for this finding is neither well-established nor has been directly tested.

Investigating light curve modulation via kernel smoothing. I. Application to 53 fundamental mode and first-overtone Cepheids in the LMC

NASA Astrophysics Data System (ADS)

Süveges, Maria; Anderson, Richard I.

2018-03-01

Context. Recent studies have revealed a hitherto unknown complexity of Cepheid pulsations by discovering irregular modulated variability using photometry, radial velocities, and interferometry. Aim. We aim to perform a statistically rigorous search and characterization of such phenomena in continuous time, applying it to 53 classical Cepheids from the OGLE-III catalog. Methods: We have used local kernel regression to search for both period and amplitude modulations simultaneously in continuous time and to investigate their detectability. We determined confidence intervals using parametric and non-parametric bootstrap sampling to estimate significance, and investigated multi-periodicity using a modified pre-whitening approach that relies on time-dependent light curve parameters. Results: We find a wide variety of period and amplitude modulations and confirm that first overtone pulsators are less stable than fundamental mode Cepheids. Significant temporal variations in period are more frequently detected than those in amplitude. We find a range of modulation intensities, suggesting that both amplitude and period modulations are ubiquitous among Cepheids. Over the 12-year baseline offered by OGLE-III, we find that period changes are often nonlinear, sometimes cyclic, suggesting physical origins beyond secular evolution. Our method detects modulations (period and amplitude) more efficiently than conventional methods that are reliant on certain features in the Fourier spectrum, and pre-whitens time series more accurately than using constant light curve parameters, removing spurious secondary peaks effectively. Conclusions: Period and amplitude modulations appear to be ubiquitous among Cepheids. Current detectability is limited by observational cadence and photometric precision: detection of amplitude modulation below 3 mmag requires space-based facilities. Recent and ongoing space missions (K2, BRITE, MOST, CoRoT) as well as upcoming ones (TESS, PLATO) will significantly improve detectability of fast modulations, such as cycle-to-cycle variations, by providing high-cadence high-precision photometry. High-quality long-term ground-based photometric time series will remain crucial to study longer-term modulations and to disentangle random fluctuations from secular evolution.

Anomalous Origin of the Left Vertebral Artery from the Aortic Arch

PubMed Central

Einstein, Evan H.; Song, Linda H.; Villela, Natalia L. A.; Fasani-Feldberg, Gregory B.; Jacobs, Jonathan L.; Kim, Dolly O.; Nathawat, Akshay; Patel, Devika; Bender, Roger B.; Peters, Daniel F.

2016-01-01

Anatomic anomalies of the aortic arch have implications for clinical practice if their significance is understood. Our case study involves a cadaveric finding of the left vertebral artery originating directly from the aortic arch. Although this anatomical variation has been documented, the prevalence of this anomaly may be generally underestimated. After noting this anomaly, we analyzed 27 cases and found that four female cadavers had the left vertebral artery originating from the aortic arch rather than the left subclavian artery. With a prevalence rate of 14.8%, it would seem that this anomaly is more significant than previously thought, which could have implications for surgical practice. PMID:27757404

Anomalous Origin of the Left Vertebral Artery from the Aortic Arch.

PubMed

Einstein, Evan H; Song, Linda H; Villela, Natalia L A; Fasani-Feldberg, Gregory B; Jacobs, Jonathan L; Kim, Dolly O; Nathawat, Akshay; Patel, Devika; Bender, Roger B; Peters, Daniel F

2016-04-01

Anatomic anomalies of the aortic arch have implications for clinical practice if their significance is understood. Our case study involves a cadaveric finding of the left vertebral artery originating directly from the aortic arch. Although this anatomical variation has been documented, the prevalence of this anomaly may be generally underestimated. After noting this anomaly, we analyzed 27 cases and found that four female cadavers had the left vertebral artery originating from the aortic arch rather than the left subclavian artery. With a prevalence rate of 14.8%, it would seem that this anomaly is more significant than previously thought, which could have implications for surgical practice.

Exploring variation-aware contig graphs for (comparative) metagenomics using MaryGold

PubMed Central

Nijkamp, Jurgen F.; Pop, Mihai; Reinders, Marcel J. T.; de Ridder, Dick

2013-01-01

Motivation: Although many tools are available to study variation and its impact in single genomes, there is a lack of algorithms for finding such variation in metagenomes. This hampers the interpretation of metagenomics sequencing datasets, which are increasingly acquired in research on the (human) microbiome, in environmental studies and in the study of processes in the production of foods and beverages. Existing algorithms often depend on the use of reference genomes, which pose a problem when a metagenome of a priori unknown strain composition is studied. In this article, we develop a method to perform reference-free detection and visual exploration of genomic variation, both within a single metagenome and between metagenomes. Results: We present the MaryGold algorithm and its implementation, which efficiently detects bubble structures in contig graphs using graph decomposition. These bubbles represent variable genomic regions in closely related strains in metagenomic samples. The variation found is presented in a condensed Circos-based visualization, which allows for easy exploration and interpretation of the found variation. We validated the algorithm on two simulated datasets containing three respectively seven Escherichia coli genomes and showed that finding allelic variation in these genomes improves assemblies. Additionally, we applied MaryGold to publicly available real metagenomic datasets, enabling us to find within-sample genomic variation in the metagenomes of a kimchi fermentation process, the microbiome of a premature infant and in microbial communities living on acid mine drainage. Moreover, we used MaryGold for between-sample variation detection and exploration by comparing sequencing data sampled at different time points for both of these datasets. Availability: MaryGold has been written in C++ and Python and can be downloaded from http://bioinformatics.tudelft.nl/software Contact: d.deridder@tudelft.nl PMID:24058058

Identification of the variations in the CPT1B and CHKB genes along with the HLA-DQB1*06:02 allele in Turkish narcolepsy patients and healthy persons.

PubMed

Cingoz, Sultan; Agilkaya, Sinem; Oztura, Ibrahim; Eroglu, Secil; Karadeniz, Derya; Evlice, Ahmet; Altungoz, Oguz; Yilmaz, Hikmet; Baklan, Baris

2014-04-01

The HLA-DQB1*06:02 allele across all ethnic groups and the rs5770917 variation between CPT1B and CHKB genes in Japanese and Koreans are common genetic susceptibility factors for narcolepsy. This comprehensive genetic study sought to assess variations in CHKB and CPT1B susceptibility genes and HLA-DQB1*06:02 allele status in Turkish patients with narcolepsy and healthy persons. CHKB/CPT1B genes were sequenced in patients with narcolepsy (n=37) and healthy persons (n=100) to detect variations. The HLA-DQB1*06:02 allele status was determined by sequence specific polymerase chain reaction. The HLA-DQB1*06:02 allele was significantly more frequent in narcoleptic patients than in healthy persons (p=2×10(-7)) and in patients with narcolepsy and cataplexy than in those without (p=0.018). The mean of the multiple sleep latency test, sleep-onset rapid eye movement periods, and frequency of sleep paralysis significantly differed in the HLA-DQB1*06:02-positive patients. rs5770917, rs5770911, rs2269381, and rs2269382 were detected together as a haplotype in three patients and 11 healthy persons. In addition to this haplotype, the indel variation (rs144647670) was detected in the 5' upstream region of the human CHKB gene in the patients and healthy persons carrying four variants together. This study identified a novel haplotype consisting of the indel variation, which had not been detected in previous studies in Japanese and Korean populations, and observed four single-nucleotide polymorphisms in CHKB/CPT1B. The study confirmed the association of the HLA-DQB1*06:02 allele with narcolepsy and cataplexy susceptibility. The findings suggest that the presence of HLA-DQB1*06:02 may be a predictor of cataplexy in narcoleptic patients and could therefore be used as an additional diagnostic marker alongside hypocretin.

The Influence of Host Galaxies in Type Ia Supernova Cosmology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uddin, Syed A.; Mould, Jeremy; Lidman, Chris

We use a sample of 1338 spectroscopically confirmed and photometrically classified Type Ia supernovae (SNe Ia) sourced from Carnegie Supernova Project, Center for Astrophysics Supernova Survey, Sloan Digital Sky Survey-II, and SuperNova Legacy Survey SN samples to examine the relationships between SNe Ia and the galaxies that host them. Our results provide confirmation with improved statistical significance that SNe Ia, after standardization, are on average more luminous in massive hosts (significance >5 σ ), and decline more rapidly in massive hosts (significance >9 σ ) and in hosts with low specific star formation rates (significance >8 σ ). We studymore » the variation of these relationships with redshift and detect no evolution. We split SNe Ia into pairs of subsets that are based on the properties of the hosts and fit cosmological models to each subset. Including both systematic and statistical uncertainties, we do not find any significant shift in the best-fit cosmological parameters between the subsets. Among different SN Ia subsets, we find that SNe Ia in hosts with high specific star formation rates have the least intrinsic scatter ( σ {sub int} = 0.08 ± 0.01) in luminosity after standardization.« less

The Influence of Host Galaxies in Type Ia Supernova Cosmology

NASA Astrophysics Data System (ADS)

Uddin, Syed A.; Mould, Jeremy; Lidman, Chris; Ruhlmann-Kleider, Vanina; Zhang, Bonnie R.

2017-10-01

We use a sample of 1338 spectroscopically confirmed and photometrically classified Type Ia supernovae (SNe Ia) sourced from Carnegie Supernova Project, Center for Astrophysics Supernova Survey, Sloan Digital Sky Survey-II, and SuperNova Legacy Survey SN samples to examine the relationships between SNe Ia and the galaxies that host them. Our results provide confirmation with improved statistical significance that SNe Ia, after standardization, are on average more luminous in massive hosts (significance >5σ), and decline more rapidly in massive hosts (significance >9σ) and in hosts with low specific star formation rates (significance >8σ). We study the variation of these relationships with redshift and detect no evolution. We split SNe Ia into pairs of subsets that are based on the properties of the hosts and fit cosmological models to each subset. Including both systematic and statistical uncertainties, we do not find any significant shift in the best-fit cosmological parameters between the subsets. Among different SN Ia subsets, we find that SNe Ia in hosts with high specific star formation rates have the least intrinsic scatter (σ int = 0.08 ± 0.01) in luminosity after standardization.

Genotypic richness predicts phenotypic variation in an endangered clonal plant

PubMed Central

Sinclair, Elizabeth A.; Poore, Alistair G.B.; Bain, Keryn F.; Vergés, Adriana

2016-01-01

Declines in genetic diversity within a species can affect the stability and functioning of populations. The conservation of genetic diversity is thus a priority, especially for threatened or endangered species. The importance of genetic variation, however, is dependent on the degree to which it translates into phenotypic variation for traits that affect individual performance and ecological processes. This is especially important for predominantly clonal species, as no single clone is likely to maximise all aspects of performance. Here we show that intraspecific genotypic diversity as measured using microsatellites is a strong predictor of phenotypic variation in morphological traits and shoot productivity of the threatened, predominantly clonal seagrass Posidonia australis, on the east coast of Australia. Biomass and surface area variation was most strongly predicted by genotypic richness, while variation in leaf chemistry (phenolics and nitrogen) was unrelated to genotypic richness. Genotypic richness did not predict tissue loss to herbivores or epiphyte load, however we did find that increased herbivore damage was positively correlated with allelic richness. Although there was no clear relationship between higher primary productivity and genotypic richness, variation in shoot productivity within a meadow was significantly greater in more genotypically diverse meadows. The proportion of phenotypic variation explained by environmental conditions varied among different genotypes, and there was generally no variation in phenotypic traits among genotypes present in the same meadows. Our results show that genotypic richness as measured through the use of presumably neutral DNA markers does covary with phenotypic variation in functionally relevant traits such as leaf morphology and shoot productivity. The remarkably long lifespan of individual Posidonia plants suggests that plasticity within genotypes has played an important role in the longevity of the species. However, the strong link between genotypic and phenotypic variation suggests that a range of genotypes is still the best case scenario for adaptation to and recovery from predicted environmental change. PMID:26925313

A Multilevel Investigation of the Association between School Context and Adolescent Nonphysical Bullying

PubMed Central

GREEN, JENNIFER GREIF; DUNN, ERIN C.; JOHNSON, RENEE M.; MOLNAR, BETH E.

2011-01-01

Although researchers have identified individual-level predictors of nonphysical bullying among children and youth, school-level predictors (i.e., characteristics of the school environment that influence bullying exposure) remain largely unstudied. Using data from a survey of 1,838 students in 21 Boston public high schools, we used multilevel modeling techniques to estimate the level of variation across schools in student reports of nonphysical bully victimization and identify school-level predictors of bullying. We found significant between school variation in youth reports of nonphysical bullying, with estimates ranging from 25–58%. We tested school-level indicators of academic performance, emotional well-being, and school safety. After controlling for individual-level covariates and demographic controls, the percent of students in the school who met with a mental health counselor was significantly associated with bullying (OR = 1.03, 95% CI = 1.01, 1.06). There was no significant association between school-level academic performance and perceptions of school safety on individual reports of bullying. Findings suggest that prevention and intervention programs may benefit from attending to the emotional well-being of students and support the importance of understanding the role of the school environment in shaping student experiences with bullying. PMID:21532943

Variation of lifespan in multiple strains, and effects of dietary restriction and BmFoxO on lifespan in silkworm, Bombyx mori.

PubMed

Song, Jiangbo; Tang, Dongmei; Li, Zhiquan; Tong, Xiaoling; Zhang, Jianfei; Han, Minjin; Hu, Hai; Lu, Cheng; Dai, Fangyin

2017-01-31

Established animal models have accelerated our understanding of the mechanisms involved in lifespan determination. However, more experimental animals are required to clarify the complex mechanisms behind the phenomena of aging and lifespan. In this study, we reported the variation of lifespan in nine distinct silkworm strains. Lifespan correlated significantly with BmFoxO gene expression in the representative silkworm strains tested (Xiafang, Dazao-N, and N4). In general, the female silkworm was longer lived than the male of the same strain. Dietary restriction extended the silkworm lifespan compared with that of silkworms fed ad libitum. The expression of BmFoxO was significantly elevated in the dietary restriction group on day 3 of the 4th instar and day 3 of the 5th instar, suggesting that BmFoxO contributes to dietary restriction-mediated lifespan extension. The RNA interference and overexpression of the BmFoxO gene significantly shortened and extended the silkworm adulthood, respectively. In conclusion, our findings suggest that the silkworm might serve as a promising experimental animal to explore the complex biological mechanisms of lifespan determination.

Acrocentric chromosome associations in man.

PubMed Central

Jacobs, P A; Mayer, M; Morton, N E

1976-01-01

Heterogeneity among chromosomes was found to be a highly significant source of variation for association proportions, while culture, slide, and observer were negligible sources of variation for association proportions although important for numbers of associations. The consequences of these results for tests of group differences are discussed. It seems evident that each pair of acrocentric chromosomes has its own characteristic probability of entering into association. This is presumably a combination of the probability for each individual member of the pair, a proposition easily tested utilizing acrocentric chromosomes carrying polymorphisms which allow each member of the pair to be individually recognized. A mathematical theory for pairwise satellite association was developed and shown to fit observations on banded chromosomes. While we found very significant heterogeneity among individuals in the frequency with which different chromosomes entered into associations, there was no significant evidence for preferential association between any particular chromosomes, either heterologous or homologous. This finding in our material of apparently random associations between different chromosomes is contrary to claims made by other investigators and should be tested on other material. No correlation was found between the phenotype of the chromosome, as judged by cytogenetic polymorphisms, and its probability of association. PMID:795295

Variations in abundance, diversity and community composition of airborne fungi in swine houses across seasons

NASA Astrophysics Data System (ADS)

Kumari, Priyanka; Woo, Cheolwoon; Yamamoto, Naomichi; Choi, Hong-Lim

2016-11-01

We examined the abundance, diversity and community composition of airborne fungi in swine houses during winter and summer seasons by using quantitative PCR and Illumina HiSeq sequencing of ITS1 region. The abundance of airborne fungi varied significantly only between seasons, while fungal diversity varied significantly both within and between seasons, with both abundance and diversity peaked in winter. The fungal OTU composition was largely structured by the swine house unit and season as well as by their interactions. Of the measured microclimate variables, relative humidity, particulate matters (PMs), ammonia, and stocking density were significantly correlated with fungal OTU composition. The variation in beta diversity was higher within swine houses during summer, which indicates that the airborne fungal community composition was more heterogeneous in summer compared to winter. We also identified several potential allergen/pathogen related fungal genera in swine houses. The total relative abundance of potential allergen/pathogen related fungal genera varied between swine houses in both seasons, and showed positive correlation with PM2.5. Overall, our findings show that the abundance, diversity and composition of airborne fungi are highly variable in swine houses and to a large extent structured by indoor microclimate variables of swine houses.

Recent worldwide expansion of Nosema ceranae (Microsporidia) in Apis mellifera populations inferred from multilocus patterns of genetic variation.

PubMed

Gómez-Moracho, T; Bartolomé, C; Bello, X; Martín-Hernández, R; Higes, M; Maside, X

2015-04-01

Nosema ceranae has been found infecting Apismellifera colonies with increasing frequency and it now represents a major threat to the health and long-term survival of these honeybees worldwide. However, so far little is known about the population genetics of this parasite. Here, we describe the patterns of genetic variation at three genomic loci in a collection of isolates from all over the world. Our main findings are: (i) the levels of genetic polymorphism (πS≈1%) do not vary significantly across its distribution range, (ii) there is substantial evidence for recombination among haplotypes, (iii) the best part of the observed genetic variance corresponds to differences within bee colonies (up to 88% of the total variance), (iv) parasites collected from Asian honeybees (Apis cerana and Apis florea) display significant differentiation from those obtained from Apismellifera (8-16% of the total variance, p<0.01) and (v) there is a significant excess of low frequency variants over neutral expectations among samples obtained from A. mellifera, but not from Asian honeybees. Overall these results are consistent with a recent colonization and rapid expansion of N. ceranae throughout A. mellifera colonies. Copyright © 2015 Elsevier B.V. All rights reserved.

The Genetic Architecture of Natural Variation in Recombination Rate in Drosophila melanogaster.

PubMed

Hunter, Chad M; Huang, Wen; Mackay, Trudy F C; Singh, Nadia D

2016-04-01

Meiotic recombination ensures proper chromosome segregation in many sexually reproducing organisms. Despite this crucial function, rates of recombination are highly variable within and between taxa, and the genetic basis of this variation remains poorly understood. Here, we exploit natural variation in the inbred, sequenced lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) to map genetic variants affecting recombination rate. We used a two-step crossing scheme and visible markers to measure rates of recombination in a 33 cM interval on the X chromosome and in a 20.4 cM interval on chromosome 3R for 205 DGRP lines. Though we cannot exclude that some biases exist due to viability effects associated with the visible markers used in this study, we find ~2-fold variation in recombination rate among lines. Interestingly, we further find that recombination rates are uncorrelated between the two chromosomal intervals. We performed a genome-wide association study to identify genetic variants associated with recombination rate in each of the two intervals surveyed. We refined our list of candidate variants and genes associated with recombination rate variation and selected twenty genes for functional assessment. We present strong evidence that five genes are likely to contribute to natural variation in recombination rate in D. melanogaster; these genes lie outside the canonical meiotic recombination pathway. We also find a weak effect of Wolbachia infection on recombination rate and we confirm the interchromosomal effect. Our results highlight the magnitude of population variation in recombination rate present in D. melanogaster and implicate new genetic factors mediating natural variation in this quantitative trait.

The Genetic Architecture of Natural Variation in Recombination Rate in Drosophila melanogaster

PubMed Central

Hunter, Chad M.; Huang, Wen; Mackay, Trudy F. C.; Singh, Nadia D.

2016-01-01

Meiotic recombination ensures proper chromosome segregation in many sexually reproducing organisms. Despite this crucial function, rates of recombination are highly variable within and between taxa, and the genetic basis of this variation remains poorly understood. Here, we exploit natural variation in the inbred, sequenced lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) to map genetic variants affecting recombination rate. We used a two-step crossing scheme and visible markers to measure rates of recombination in a 33 cM interval on the X chromosome and in a 20.4 cM interval on chromosome 3R for 205 DGRP lines. Though we cannot exclude that some biases exist due to viability effects associated with the visible markers used in this study, we find ~2-fold variation in recombination rate among lines. Interestingly, we further find that recombination rates are uncorrelated between the two chromosomal intervals. We performed a genome-wide association study to identify genetic variants associated with recombination rate in each of the two intervals surveyed. We refined our list of candidate variants and genes associated with recombination rate variation and selected twenty genes for functional assessment. We present strong evidence that five genes are likely to contribute to natural variation in recombination rate in D. melanogaster; these genes lie outside the canonical meiotic recombination pathway. We also find a weak effect of Wolbachia infection on recombination rate and we confirm the interchromosomal effect. Our results highlight the magnitude of population variation in recombination rate present in D. melanogaster and implicate new genetic factors mediating natural variation in this quantitative trait. PMID:27035832

Compost Addition Enhanced Hyphal Growth and Sporulation of Arbuscular Mycorrhizal Fungi without Affecting Their Community Composition in the Soil

PubMed Central

Yang, Wei; Gu, Siyu; Xin, Ying; Bello, Ayodeji; Sun, Wenpeng; Xu, Xiuhong

2018-01-01

Arbuscular mycorrhizal (AM) fungi form symbiotic associations with most crop plant species in agricultural ecosystems, and are conspicuously influenced by various agricultural practices. To understand the impact of compost addition on AM fungi, we examined effect of four compost rates (0, 11.25, 22.5, and 45 Mg/ha) on the abundance and community composition of AM fungi in seedling, flowering, and mature stage of soybean in a 1-year compost addition experiment system in Northeast China. Soybean [Glycine max (L.) Merrill] was used as test plant. Moderate (22.5 Mg/ha) and high (45 Mg/ha) levels of compost addition significantly increased AM root colonization and extraradical hyphal (ERH) density compared with control, whereas low (11.5 Mg/ha) level of compost addition did not cause significant increase in AM root colonization and ERH density. AM fungal spore density was significantly enhanced by all the compost rates compared with control. The temporal variations analysis revealed that, AM root colonization in seedling stage was significantly lower than in flowering and mature stage. Although AM fungal operational taxonomic unit richness and community composition was unaffected by compost addition, some abundant AM fungal species showed significantly different response to compost addition. In mature stage, Rhizophagus fasciculatum showed increasing trend along with compost addition gradient, whereas the opposite was observed with Paraglomus sp. In addition, AM fungal community composition exhibited significant temporal variation during growing season. Further analysis indicated that the temporal variation in AM fungal community only occurred in control treatment, but not in low, moderate, and high level of compost addition treatments. Our findings highlighted the significant effects of compost addition on AM growth and sporulation, and emphasized that growth stage is a stronger determinant than 1-year compost addition in shaping AM fungal community in black soil of Northeast China. PMID:29467752

Compost Addition Enhanced Hyphal Growth and Sporulation of Arbuscular Mycorrhizal Fungi without Affecting Their Community Composition in the Soil.

PubMed

Yang, Wei; Gu, Siyu; Xin, Ying; Bello, Ayodeji; Sun, Wenpeng; Xu, Xiuhong

2018-01-01

Arbuscular mycorrhizal (AM) fungi form symbiotic associations with most crop plant species in agricultural ecosystems, and are conspicuously influenced by various agricultural practices. To understand the impact of compost addition on AM fungi, we examined effect of four compost rates (0, 11.25, 22.5, and 45 Mg/ha) on the abundance and community composition of AM fungi in seedling, flowering, and mature stage of soybean in a 1-year compost addition experiment system in Northeast China. Soybean [ Glycine max (L.) Merrill] was used as test plant. Moderate (22.5 Mg/ha) and high (45 Mg/ha) levels of compost addition significantly increased AM root colonization and extraradical hyphal (ERH) density compared with control, whereas low (11.5 Mg/ha) level of compost addition did not cause significant increase in AM root colonization and ERH density. AM fungal spore density was significantly enhanced by all the compost rates compared with control. The temporal variations analysis revealed that, AM root colonization in seedling stage was significantly lower than in flowering and mature stage. Although AM fungal operational taxonomic unit richness and community composition was unaffected by compost addition, some abundant AM fungal species showed significantly different response to compost addition. In mature stage, Rhizophagus fasciculatum showed increasing trend along with compost addition gradient, whereas the opposite was observed with Paraglomus sp. In addition, AM fungal community composition exhibited significant temporal variation during growing season. Further analysis indicated that the temporal variation in AM fungal community only occurred in control treatment, but not in low, moderate, and high level of compost addition treatments. Our findings highlighted the significant effects of compost addition on AM growth and sporulation, and emphasized that growth stage is a stronger determinant than 1-year compost addition in shaping AM fungal community in black soil of Northeast China.

The importance of dental aesthetics among dental students assessment of knowledge

PubMed Central

Manipal, Sunayana; Mohan, C. S. Anand; Kumar, D. Lokesh; Cholan, Priyanka K.; Ahmed, Adil; Adusumilli, Preethi

2014-01-01

Objective: The aim of this study is to assess the dental esthetics awareness among dental students in a private university in Chennai as none is available in Chennai, Tamil Nadu. Materials and Methods: The dental esthetics awareness questionnaire consisting of a battery of 19 questions under five aspects that is, physical, functional, social, knowledge, and psychological aspects was administered to a sample of 100 dental college students aged between 18 and 27 years in a private college in Chennai, India. Gender variations on the responses of their effects and the impact on dental esthetics awareness had been analyzed using a Chi-square test. Results: With respect to physical aspects, pigmentation shows more significance as students want to get treated for their pigmentation of lips and gums. With respect to functional aspects, eating shows more significance as students have difficulty while eating. In social aspects, habits show more significance as it affects their esthetics. With respect to psychological aspects, mental depression shows more significance as students feel more deprived due to their unesthetic appearance. Conclusion: This study shows a high level of self-consciousness and the findings of the studies prove that even the slightest of variations have a greater impact on the above-mentioned dimensions in particular to psychological, functional, and physical aspects. PMID:24818095

The importance of dental aesthetics among dental students assessment of knowledge.

PubMed

Manipal, Sunayana; Mohan, C S Anand; Kumar, D Lokesh; Cholan, Priyanka K; Ahmed, Adil; Adusumilli, Preethi

2014-01-01

The aim of this study is to assess the dental esthetics awareness among dental students in a private university in Chennai as none is available in Chennai, Tamil Nadu. The dental esthetics awareness questionnaire consisting of a battery of 19 questions under five aspects that is, physical, functional, social, knowledge, and psychological aspects was administered to a sample of 100 dental college students aged between 18 and 27 years in a private college in Chennai, India. Gender variations on the responses of their effects and the impact on dental esthetics awareness had been analyzed using a Chi-square test. With respect to physical aspects, pigmentation shows more significance as students want to get treated for their pigmentation of lips and gums. With respect to functional aspects, eating shows more significance as students have difficulty while eating. In social aspects, habits show more significance as it affects their esthetics. With respect to psychological aspects, mental depression shows more significance as students feel more deprived due to their unesthetic appearance. This study shows a high level of self-consciousness and the findings of the studies prove that even the slightest of variations have a greater impact on the above-mentioned dimensions in particular to psychological, functional, and physical aspects.

Trans-Ethnic Meta-Analysis Identifies Common and Rare Variants Associated with Hepatocyte Growth Factor Levels in the Multi-Ethnic Study of Atherosclerosis (MESA)

PubMed Central

Larson, Nicholas B.; Berardi, Cecilia; Decker, Paul A.; Wassel, Christina L.; Kirsch, Phillip S.; Pankow, James S.; Sale, Michele M.; de Andrade, Mariza; Sicotte, Hugues; Tang, Weihong; Hanson, Naomi Q.; Tsai, Michael Y.; Taylor, Kent D.; Bielinski, Suzette J.

2015-01-01

Summary Hepatocyte growth factor (HGF) is a mesenchyme-derived pleiotropic factor that regulates cell growth, motility, mitogenesis, and morphogenesis in a variety of cells, and increased serum levels of HGF have been linked to a number of clinical and subclinical cardiovascular disease phenotypes. However, little is currently known regarding what genetic factors influence HGF levels, despite evidence of substantial genetic contributions to HGF variation. Based upon ethnicity-stratified single-variant association analysis and trans-ethnic meta-analysis of 6201 participants of the Multi-Ethnic Study of Atherosclerosis (MESA), we discovered five statistically significant common and low-frequency variants: HGF missense polymorphism rs5745687 (p.E299K) as well as four variants (rs16844364, rs4690098, rs114303452, rs3748034) within or in proximity to HGFAC. We also identified two significant ethnicity-specific gene-level associations (A1BG in African Americans; FASN in Chinese Americans) based upon low-frequency/rare variants, while meta-analysis of gene-level results identified a significant association for HGFAC. However, identified single-variant associations explained modest proportions of the total trait variation and were not significantly associated with coronary artery calcium or coronary heart disease. Our findings indicate genetic factors influencing circulating HGF levels may be complex and ethnically diverse. PMID:25998175

Quantifying Neonatal Sucking Performance: Promise of New Methods.

PubMed

Capilouto, Gilson J; Cunningham, Tommy J; Mullineaux, David R; Tamilia, Eleonora; Papadelis, Christos; Giannone, Peter J

2017-04-01

Neonatal feeding has been traditionally understudied so guidelines and evidence-based support for common feeding practices are limited. A major contributing factor to the paucity of evidence-based practice in this area has been the lack of simple-to-use, low-cost tools for monitoring sucking performance. We describe new methods for quantifying neonatal sucking performance that hold significant clinical and research promise. We present early results from an ongoing study investigating neonatal sucking as a marker of risk for adverse neurodevelopmental outcomes. We include quantitative measures of sucking performance to better understand how movement variability evolves during skill acquisition. Results showed the coefficient of variation of suck duration was significantly different between preterm neonates at high risk for developmental concerns (HRPT) and preterm neonates at low risk for developmental concerns (LRPT). For HRPT, results indicated the coefficient of variation of suck smoothness increased from initial feeding to discharge and remained significantly greater than healthy full-term newborns (FT) at discharge. There was no significant difference in our measures between FT and LRPT at discharge. Our findings highlight the need to include neonatal sucking assessment as part of routine clinical care in order to capture the relative risk of adverse neurodevelopmental outcomes at discharge. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Clinical Interpretation and Implications of Whole-Genome Sequencing

PubMed Central

Dewey, Frederick E.; Grove, Megan E.; Pan, Cuiping; Goldstein, Benjamin A.; Bernstein, Jonathan A.; Chaib, Hassan; Merker, Jason D.; Goldfeder, Rachel L.; Enns, Gregory M.; David, Sean P.; Pakdaman, Neda; Ormond, Kelly E.; Caleshu, Colleen; Kingham, Kerry; Klein, Teri E.; Whirl-Carrillo, Michelle; Sakamoto, Kenneth; Wheeler, Matthew T.; Butte, Atul J.; Ford, James M.; Boxer, Linda; Ioannidis, John P. A.; Yeung, Alan C.; Altman, Russ B.; Assimes, Themistocles L.; Snyder, Michael; Ashley, Euan A.; Quertermous, Thomas

2014-01-01

IMPORTANCE Whole-genome sequencing (WGS) is increasingly applied in clinical medicine and is expected to uncover clinically significant findings regardless of sequencing indication. OBJECTIVES To examine coverage and concordance of clinically relevant genetic variation provided by WGS technologies; to quantitate inherited disease risk and pharmacogenomic findings in WGS data and resources required for their discovery and interpretation; and to evaluate clinical action prompted by WGS findings. DESIGN, SETTING, AND PARTICIPANTS An exploratory study of 12 adult participants recruited at Stanford University Medical Center who underwent WGS between November 2011 and March 2012. A multidisciplinary team reviewed all potentially reportable genetic findings. Five physicians proposed initial clinical follow-up based on the genetic findings. MAIN OUTCOMES AND MEASURES Genome coverage and sequencing platform concordance in different categories of genetic disease risk, person-hours spent curating candidate disease-risk variants, interpretation agreement between trained curators and disease genetics databases, burden of inherited disease risk and pharmacogenomic findings, and burden and interrater agreement of proposed clinical follow-up. RESULTS Depending on sequencing platform, 10% to 19% of inherited disease genes were not covered to accepted standards for single nucleotide variant discovery. Genotype concordance was high for previously described single nucleotide genetic variants (99%-100%) but low for small insertion/deletion variants (53%-59%). Curation of 90 to 127 genetic variants in each participant required a median of 54 minutes (range, 5-223 minutes) per genetic variant, resulted in moderate classification agreement between professionals (Gross κ, 0.52; 95%CI, 0.40-0.64), and reclassified 69%of genetic variants cataloged as disease causing in mutation databases to variants of uncertain or lesser significance. Two to 6 personal disease-risk findings were discovered in each participant, including 1 frameshift deletion in the BRCA1 gene implicated in hereditary breast and ovarian cancer. Physician review of sequencing findings prompted consideration of a median of 1 to 3 initial diagnostic tests and referrals per participant, with fair interrater agreement about the suitability of WGS findings for clinical follow-up (Fleiss κ, 0.24; P < 001). CONCLUSIONS AND RELEVANCE In this exploratory study of 12 volunteer adults, the use of WGS was associated with incomplete coverage of inherited disease genes, low reproducibility of detection of genetic variation with the highest potential clinical effects, and uncertainty about clinically reportable findings. In certain cases, WGS will identify clinically actionable genetic variants warranting early medical intervention. These issues should be considered when determining the role of WGS in clinical medicine. PMID:24618965

Differences in the thermal physiology of adult Yarrow's spiny lizards (Sceloporus jarrovii) in relation to sex and body size.

PubMed

Beal, Martin S; Lattanzio, Matthew S; Miles, Donald B

2014-11-01

Sexual size dimorphism (SSD) is often assumed to reflect the phenotypic consequences of differential selection operating on each sex. Species that exhibit SSD may also show intersexual differences in other traits, including field-active body temperatures, preferred temperatures, and locomotor performance. For these traits, differences may be correlated with differences in body size or reflect sex-specific trait optima. Male and female Yarrow's spiny lizards, Sceloporus jarrovii, in a population in southeastern Arizona exhibit a difference in body temperature that is unrelated to variation in body size. The observed sexual variation in body temperature may reflect divergence in thermal physiology between the sexes. To test this hypothesis, we measured the preferred body temperatures of male and female lizards when recently fed and fasted. We also estimated the thermal sensitivity of stamina at seven body temperatures. Variation in these traits provided an opportunity to determine whether body size or sex-specific variation unrelated to size shaped their thermal physiology. Female lizards, but not males, preferred a lower body temperature when fasted, and this pattern was unrelated to body size. Larger individuals exhibited greater stamina, but we detected no significant effect of sex on the shape or height of the thermal performance curves. The thermal preference of males and females in a thermal gradient exceeded the optimal temperature for performance in both sexes. Our findings suggest that differences in thermal physiology are both sex- and size-based and that peak performance at low body temperatures may be adaptive given the reproductive cycles of this viviparous species. We consider the implications of our findings for the persistence of S. jarrovii and other montane ectotherms in the face of climate warming.

Differences in the thermal physiology of adult Yarrow's spiny lizards (Sceloporus jarrovii) in relation to sex and body size

PubMed Central

Beal, Martin S; Lattanzio, Matthew S; Miles, Donald B

2014-01-01

Sexual size dimorphism (SSD) is often assumed to reflect the phenotypic consequences of differential selection operating on each sex. Species that exhibit SSD may also show intersexual differences in other traits, including field-active body temperatures, preferred temperatures, and locomotor performance. For these traits, differences may be correlated with differences in body size or reflect sex-specific trait optima. Male and female Yarrow's spiny lizards, Sceloporus jarrovii, in a population in southeastern Arizona exhibit a difference in body temperature that is unrelated to variation in body size. The observed sexual variation in body temperature may reflect divergence in thermal physiology between the sexes. To test this hypothesis, we measured the preferred body temperatures of male and female lizards when recently fed and fasted. We also estimated the thermal sensitivity of stamina at seven body temperatures. Variation in these traits provided an opportunity to determine whether body size or sex-specific variation unrelated to size shaped their thermal physiology. Female lizards, but not males, preferred a lower body temperature when fasted, and this pattern was unrelated to body size. Larger individuals exhibited greater stamina, but we detected no significant effect of sex on the shape or height of the thermal performance curves. The thermal preference of males and females in a thermal gradient exceeded the optimal temperature for performance in both sexes. Our findings suggest that differences in thermal physiology are both sex- and size-based and that peak performance at low body temperatures may be adaptive given the reproductive cycles of this viviparous species. We consider the implications of our findings for the persistence of S. jarrovii and other montane ectotherms in the face of climate warming. PMID:25540684

Cross-Cultural Patterns in Dynamic Ratings of Positive and Negative Natural Emotional Behaviour

PubMed Central

Sneddon, Ian; McKeown, Gary; McRorie, Margaret; Vukicevic, Tijana

2011-01-01

Background Studies of cross-cultural variations in the perception of emotion have typically compared rates of recognition of static posed stimulus photographs. That research has provided evidence for universality in the recognition of a range of emotions but also for some systematic cross-cultural variation in the interpretation of emotional expression. However, questions remain about how widely such findings can be generalised to real life emotional situations. The present study provides the first evidence that the previously reported interplay between universal and cultural influences extends to ratings of natural, dynamic emotional stimuli. Methodology/Principal Findings Participants from Northern Ireland, Serbia, Guatemala and Peru used a computer based tool to continuously rate the strength of positive and negative emotion being displayed in twelve short video sequences by people from the United Kingdom engaged in emotional conversations. Generalized additive mixed models were developed to assess the differences in perception of emotion between countries and sexes. Our results indicate that the temporal pattern of ratings is similar across cultures for a range of emotions and social contexts. However, there are systematic differences in intensity ratings between the countries, with participants from Northern Ireland making the most extreme ratings in the majority of the clips. Conclusions/Significance The results indicate that there is strong agreement across cultures in the valence and patterns of ratings of natural emotional situations but that participants from different cultures show systematic variation in the intensity with which they rate emotion. Results are discussed in terms of both ‘in-group advantage’ and ‘display rules’ approaches. This study indicates that examples of natural spontaneous emotional behaviour can be used to study cross-cultural variations in the perception of emotion. PMID:21364739

Appropriate threshold levels of cardiac beat-to-beat variation in semi-automatic analysis of equine ECG recordings.

PubMed

Flethøj, Mette; Kanters, Jørgen K; Pedersen, Philip J; Haugaard, Maria M; Carstensen, Helena; Olsen, Lisbeth H; Buhl, Rikke

2016-11-28

Although premature beats are a matter of concern in horses, the interpretation of equine ECG recordings is complicated by a lack of standardized analysis criteria and a limited knowledge of the normal beat-to-beat variation of equine cardiac rhythm. The purpose of this study was to determine the appropriate threshold levels of maximum acceptable deviation of RR intervals in equine ECG analysis, and to evaluate a novel two-step timing algorithm by quantifying the frequency of arrhythmias in a cohort of healthy adult endurance horses. Beat-to-beat variation differed considerably with heart rate (HR), and an adaptable model consisting of three different HR ranges with separate threshold levels of maximum acceptable RR deviation was consequently defined. For resting HRs <60 beats/min (bpm) the threshold level of RR deviation was set at 20%, for HRs in the intermediate range between 60 and 100 bpm the threshold was 10%, and for exercising HRs >100 bpm, the threshold level was 4%. Supraventricular premature beats represented the most prevalent arrhythmia category with varying frequencies in seven horses at rest (median 7, range 2-86) and six horses during exercise (median 2, range 1-24). Beat-to-beat variation of equine cardiac rhythm varies according to HR, and threshold levels in equine ECG analysis should be adjusted accordingly. Standardization of the analysis criteria will enable comparisons of studies and follow-up examinations of patients. A small number of supraventricular premature beats appears to be a normal finding in endurance horses. Further studies are required to validate the findings and determine the clinical significance of premature beats in horses.

Variance Function Regression in Hierarchical Age-Period-Cohort Models: Applications to the Study of Self-Reported Health

PubMed Central

Zheng, Hui; Yang, Yang; Land, Kenneth C.

2012-01-01

Two long-standing research problems of interest to sociologists are sources of variations in social inequalities and differential contributions of the temporal dimensions of age, time period, and cohort to variations in social phenomena. Recently, scholars have introduced a model called Variance Function Regression for the study of the former problem, and a model called Hierarchical Age-Period-Cohort regression has been developed for the study of the latter. This article presents an integration of these two models as a means to study the evolution of social inequalities along distinct temporal dimensions. We apply the integrated model to survey data on subjective health status. We find substantial age, period, and cohort effects, as well as gender differences, not only for the conditional mean of self-rated health (i.e., between-group disparities), but also for the variance in this mean (i.e., within-group disparities)—and it is detection of age, period, and cohort variations in the latter disparities that application of the integrated model permits. Net of effects of age and individual-level covariates, in recent decades, cohort differences in conditional means of self-rated health have been less important than period differences that cut across all cohorts. By contrast, cohort differences of variances in these conditional means have dominated period differences. In particular, post-baby boom birth cohorts show significant and increasing levels of within-group disparities. These findings illustrate how the integrated model provides a powerful framework through which to identify and study the evolution of variations in social inequalities across age, period, and cohort temporal dimensions. Accordingly, this model should be broadly applicable to the study of social inequality in many different substantive contexts. PMID:22904570

On the forces that drive and resist deformation of the south-central Mediterranean: a mechanical model study

NASA Astrophysics Data System (ADS)

Nijholt, Nicolai; Govers, Rob; Wortel, Rinus

2018-04-01

The geodynamics of the Mediterranean comprises a transitional setting in which slab rollback and plate convergence compete to shape the region. In the central Mediterranean, where the balance of driving and resisting forces changes continuously and rapidly since the Miocene, both kinematic and seismo-tectonic observations display a strong variation in deformation style and, therefore possibly, lithospheric forces. We aim to understand the current kinematics in southern Italy and Sicily in terms of lithospheric forces that cause them. The strong regional variation of geodetic velocities appears to prohibit such simple explanation. We use mechanical models to quantify the deformation resulting from large-scale Africa-Eurasia convergence, ESE retreat of the Calabrian subduction zone, pull by the Aegean slab, and regional variations in gravitational potential energy (topography). A key model element is the resistance to slip on major regional fault zones. We show that geodetic velocities, seismicity and sense of slip on regional faults can be understood to result from lithospheric forces. Our most important new finding is that regional variations in resistive tractions are required to fit the observations, with notably very low tractions on the Calabrian subduction contact, and a buildup towards a significant earthquake in the Calabrian fore-arc. We also find that the Calabrian net slab pull force is strongly reduced (compared to the value possible in view of the slab's dimensions) and that trench suction tractions are negligible. Such very small contributions to the present-day force balance in the south-central Mediterranean suggest that the Calabrian arc is now further transitioning towards a setting dominated by Africa-Eurasia plate convergence, whereas during the past 30 Myrs slab retreat continually was the dominant factor.

Particle-in-cell simulations for virtual cathode oscillator including foil ablation effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Gursharn; Chaturvedi, S.

2011-06-15

We have performed two- and three-dimensional, relativistic, electromagnetic, particle-in-cell simulations of an axially extracted virtual cathode oscillator (vircator). The simulations include, for the first time, self-consistent dynamics of the anode foil under the influence of the intense electron beam. This yields the variation of microwave output power as a function of time, including the role of anode ablation and anode-cathode gap closure. These simulations have been done using locally developed particle-in-cell (PIC) codes. The codes have been validated using two vircator designs available from the literature. The simulations reported in the present paper take account of foil ablation due tomore » the intense electron flux, the resulting plasma expansion and shorting of the anode-cathode gap. The variation in anode transparency due to plasma formation is automatically taken into account. We find that damage is generally higher near the axis. Also, at all radial positions, there is little damage in the early stages, followed by a period of rapid erosion, followed in turn by low damage rates. A physical explanation has been given for these trends. As a result of gap closure due to plasma formation from the foil, the output microwave power initially increases, reaches a near-flat-top and then decreases steadily, reaching a minimum around 230 ns. This is consistent with a typical plasma expansion velocity of {approx}2 cm/{mu}s reported in the literature. We also find a significant variation in the dominant output frequency, from 6.3 to 7.6 GHz. This variation is small as long as the plasma density is small, up to {approx}40 ns. As the AK gap starts filling with plasma, there is a steady increase in this frequency.« less