WorldWideScience

Sample records for causing natural variation

  1. Evidence that Natural Selection is the Primary Cause of the Guanine-cytosine Content Variation in Rice Genes

    Institute of Scientific and Technical Information of China (English)

    Xiaoli Shi; Xiyin Wang; Zhe Li; Qihui Zhu; Ji Yang; Song Ge; Jingchu Luo

    2007-01-01

    Cereal genes are classified into two distinct classes according to the guanine-cytosine (GC) content at the third codon sites (GC3). Natural selection and mutation bias have been proposed to affect the GC content. However, there has been controversy about the cause of GC variation. Here, we characterized the GC content of 1 092 paralogs and other single-copy genes in the duplicated chromosomal regions of the rice genome (ssp. indica) and classified the paralogs into GC3-rich and GC3-poor groups. By referring to out-group sequences from Arabidopsis and maize, we confirmed that the average synonymous substitution rate of the GC3-rich genes is significantly lower than that of the GC3-poor genes. Furthermore,we explored the other possible factors corresponding to the GC variation including the length of coding sequences, the number of exons in each gene, the number of genes in each family, the location of genes on chromosomes and the protein functions. Consequently, we propose that natural selection rather than mutation bias was the primary cause of the GC variation.

  2. Salinity variations in the water resources fed by the Etnean volcanic aquifers (Sicily, Italy): natural vs. anthropogenic causes.

    Science.gov (United States)

    D'Alessandro, Walter; Bellomo, Sergio; Bonfanti, Pietro; Brusca, Lorenzo; Longo, Manfredi

    2011-02-01

    In this paper, in an attempt to reveal possible changes connected to natural or anthropogenic causes, the main results of hydrogeochemical monitoring carried out at Mount Etna are evaluated. We report on the salinity contents of the groundwaters that flow in fractured volcanics, which make up the flanks of the volcano. These waters, analyzed for major ion chemistry, were sampled regularly from 1994 to 2004. Basing on nonparametric Sen's slope estimator, time series of groundwater composition reveal that the salinity of most of the Etnean aquifers increased by 0.5% to 3.5% each year during this period. This change in the water chemistry is clearly referable to the overexploitation of the aquifers. This increasing trend needs to be inverted urgently; otherwise, it will cause a shortage of water in the near future, because the maximum admissible concentration of salinity for drinking water will be exceeded.

  3. Genetic structure and natural variation associated with host of origin in Penicillium expansum strains causing blue mould.

    Science.gov (United States)

    Sanzani, S M; Montemurro, C; Di Rienzo, V; Solfrizzo, M; Ippolito, A

    2013-07-15

    Blue mould, caused by Penicillium expansum, is one of the most economically damaging postharvest diseases of pome fruits, although it may affect a wider host range, including sweet cherries and table grapes. Several reports on the role of mycotoxins in plant pathogenesis have been published, but few focussed on the influence of mycotoxins on the variation in host preference amongst producing fungi. In the present study the influence of the host on P. expansum pathogenicity/virulence was investigated, focussing mainly on the relationship with patulin production. Three P. expansum strain groups, originating from apples, sweet cherries, and table grapes (7 strains per host) were grown on their hosts of isolation and on artificial media derived from them. Strains within each P. expansum group proved to be more aggressive and produced more patulin than the other two groups under evaluation when grown on the host from which they originated. Table grape strains were the most aggressive (81% disease incidence) and strongest patulin producers (up to 554μg/g). The difference in aggressiveness amongst strains was appreciable only in the presence of a living host, suggesting that the complex pathogen-host interaction significantly influenced the ability of P. expansum to cause the disease. Incidence/severity of the disease and patulin production proved to be positively correlated, supporting the role of patulin as virulence/pathogenicity factor. The existence of genetic variation amongst isolates was confirmed by the High Resolution Melting method that was set up herein, which permitted discrimination of P. expansum from other species (P. chrysogenum and P. crustosum) and, within the same species, amongst the host of origin. Host effect on toxin production appeared to be exerted at a transcriptional level.

  4. Exploiting Natural Variation in Arabidopsis

    NARCIS (Netherlands)

    Molenaar, J.A.; Keurentjes, J.J.B.

    2014-01-01

    Natural variation for many traits is present within the species Arabidopsis thaliana . This chapter describes the use of natural variation to elucidate genes underlying the regulation of quantitative traits. It deals with the development and use of mapping populations, the detection and handling of

  5. Exploiting natural variation in Arabidopsis

    NARCIS (Netherlands)

    J.A. Molenaar; J.J.B. Keurentjes

    2014-01-01

    Natural variation for many traits is present within the species Arabidopsis thaliana. This chapter describes the use of natural variation to elucidate genes underlying the regulation of quantitative traits. It deals with the development and use of mapping populations, the detection and handling of g

  6. Causes for variation in pork quality

    NARCIS (Netherlands)

    Wal, van der P.; Engel, B.; Hulsegge, B.

    1997-01-01

    Research was carried out on 260 pigs that were slaughtered in 12 batches in the slaughter facilities of ID-DLO at Zeist. The practical circumstances were highly standardized. The 'animals' meat quality was good with only little variation; 46 animals showed a 'slightly' aberrant quality and 6 'slight

  7. Gene Tree Discordance Causes Apparent Substitution Rate Variation.

    Science.gov (United States)

    Mendes, Fábio K; Hahn, Matthew W

    2016-07-01

    Substitution rates are known to be variable among genes, chromosomes, species, and lineages due to multifarious biological processes. Here, we consider another source of substitution rate variation due to a technical bias associated with gene tree discordance. Discordance has been found to be rampant in genome-wide data sets, often due to incomplete lineage sorting (ILS). This apparent substitution rate variation is caused when substitutions that occur on discordant gene trees are analyzed in the context of a single, fixed species tree. Such substitutions have to be resolved by proposing multiple substitutions on the species tree, and we therefore refer to this phenomenon as Substitutions Produced by ILS (SPILS). We use simulations to demonstrate that SPILS has a larger effect with increasing levels of ILS, and on trees with larger numbers of taxa. Specific branches of the species trees are consistently, but erroneously, inferred to be longer or shorter, and we show that these branches can be predicted based on discordant tree topologies. Moreover, we observe that fixing a species tree topology when performing tests of positive selection increases the false positive rate, particularly for genes whose discordant topologies are most affected by SPILS. Finally, we use data from multiple Drosophila species to show that SPILS can be detected in nature. Although the effects of SPILS are modest per gene, it has the potential to affect substitution rate variation whenever high levels of ILS are present, particularly in rapid radiations. The problems outlined here have implications for character mapping of any type of trait, and for any biological process that causes discordance. We discuss possible solutions to these problems, and areas in which they are likely to have caused faulty inferences of convergence and accelerated evolution.

  8. Comprehensive profiling and natural variation of flavonoids in rice

    Institute of Scientific and Technical Information of China (English)

    Xuekui Dong; Wei Chen; Wensheng Wang; Hongyan Zhang; Xianqing Liu; Jie Luo

    2014-01-01

    Flavonoids constitute a major group of plant phenolic compounds. While extensively studied in Arabidopsis, profiling and natural y occurring variation of these compounds in rice (Oryza sativa), the monocot model plant, are less reported. Using a col ection of rice germplasm, comprehensive profiling and natural variation of flavonoids were presented in this report. Application of a widely targeted metabolomics method facilitat-ed the simultaneous identification and quantification of more than 90 flavonoids using liquid chromatography tandem mass spectrometry (LC-MS/MS). Comparing flavonoid contents in various tissues during different developmental stages revealed tissue-specific accumulation of most flavonoids. Further investi-gation indicated that flavone mono-C-glycosides, malonylated flavonoid O-hexosides, and some flavonoid O-glycosides accu-mulated at significantly higher levels in indica than in japonica, while the opposite was observed for aromatic acylated flavone C-hexosyl-O-hexosides. In contrast to the highly differential accumulation between the two subspecies, relatively smal variations within subspecies were detected for most flavonoids. Besides, an association analysis between flavonoid accumulation and its biosynthetic gene sequence polymorphisms disclosed that natural variation of flavonoids was probably caused by sequence polymorphisms in the coding region of flavonoid biosynthetic genes. Our work paves the way for future dissection of biosynthesis and regulation of flavonoid pathway in rice.

  9. River pollution caused by natural stone industry

    Science.gov (United States)

    Oktriani, Ani; Darmajanti, Linda; Soesilo, Tri Edhi Budhi

    2017-03-01

    The natural stone industry is classified as small industry. Current wastewater treatment still causes pollution in the river. This thesis aims to analyze the performance of wastewater treatment in natural stones industry. The data was collected from water quality test (parameters: temperature, pH, DO, and TSS). The wastewater treatment performance was in a slightly higher position compared to the 2nd class quality standards of Government Regulation No. 82/2001. The parameter that exceeded quality standards was the concentration of TSS, which was up to 240.8 mg/l. The high concentration of TSS was affected by the absence of sludge management schedule, which resulted in non-optimal precipitation. Besides that, the design of sedimentation basin was still not adapted with wastewater debit. Referring to the results, this study suggests the government of Cirebon District to provide wastewater treatment development through the village staff. Furthermore, the government also needs to give strict punishment to business owner who does not treat waste correctly and does not have a business license. Moreover, the sale value of sludge as byproduct of wastewater treatment needs to be increased.

  10. Genetic architecture of natural variation in Drosophila melanogaster aggressive behavior.

    Science.gov (United States)

    Shorter, John; Couch, Charlene; Huang, Wen; Carbone, Mary Anna; Peiffer, Jason; Anholt, Robert R H; Mackay, Trudy F C

    2015-07-07

    Aggression is an evolutionarily conserved complex behavior essential for survival and the organization of social hierarchies. With the exception of genetic variants associated with bioamine signaling, which have been implicated in aggression in many species, the genetic basis of natural variation in aggression is largely unknown. Drosophila melanogaster is a favorable model system for exploring the genetic basis of natural variation in aggression. Here, we performed genome-wide association analyses using the inbred, sequenced lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) and replicate advanced intercross populations derived from the most and least aggressive DGRP lines. We identified genes that have been previously implicated in aggressive behavior as well as many novel loci, including gustatory receptor 63a (Gr63a), which encodes a subunit of the receptor for CO2, and genes associated with development and function of the nervous system. Although genes from the two association analyses were largely nonoverlapping, they mapped onto a genetic interaction network inferred from an analysis of pairwise epistasis in the DGRP. We used mutations and RNAi knock-down alleles to functionally validate 79% of the candidate genes and 75% of the candidate epistatic interactions tested. Epistasis for aggressive behavior causes cryptic genetic variation in the DGRP that is revealed by changing allele frequencies in the outbred populations derived from extreme DGRP lines. This phenomenon may pertain to other fitness traits and species, with implications for evolution, applied breeding, and human genetics.

  11. Contextual dissonance effects: nature and causes.

    Science.gov (United States)

    Rosenberg, M

    1977-08-01

    Contextual consonance or dissonance refers to the concordance of, or the discrepancy between, the individual's social characteristics and those of the population by which he is surrounded. Although a number of advantageous consequences have been shown to issue from contextual dissonance, self-esteem is not one of them. This article seeks to account for the deleterious effect of contextual dissonance on self-esteem by examining the nature of dissonant communications environments, dissonant cultural environments, and dissonant comparison reference groups.

  12. [A brief history of the natural causes of human disease].

    Science.gov (United States)

    Lips-Castro, Walter

    2015-01-01

    In the study of the causes of disease that have arisen during the development of humankind, one can distinguish three major perspectives: the natural, the supernatural, and the artificial. In this paper we distinguish the rational natural causes of disease from the irrational natural causes. Within the natural and rational causal approaches of disease, we can highlight the Egyptian theory of putrid intestinal materials called "wechdu", the humoral theory, the atomistic theory, the contagious theory, the cellular theory, the molecular (genetic) theory, and the ecogenetic theory. Regarding the irrational, esoteric, and mystic causal approaches to disease, we highlight the astrological, the alchemical, the iatrochemical, the iatromechanical, and others (irritability, solidism, brownism, and mesmerism).

  13. Does natural variation in diversity affect biotic resistance?

    Science.gov (United States)

    Harrison, Susan; Cornell, Howard; Grace, James B.

    2015-01-01

    Theories linking diversity to ecosystem function have been challenged by the widespread observation of more exotic species in more diverse native communities. Few studies have addressed the key underlying process by dissecting how community diversity is shaped by the same environmental gradients that determine biotic and abiotic resistance to new invaders. In grasslands on highly heterogeneous soils, we used addition of a recent invader, competitor removal and structural equation modelling (SEM) to analyse soil influences on community diversity, biotic and abiotic resistance and invader success. Biotic resistance, measured by reduction in invader success in the presence of the resident community, was negatively correlated with species richness and functional diversity. However, in the multivariate SEM framework, biotic resistance was independent of all forms of diversity and was positively affected by soil fertility via community biomass. Abiotic resistance, measured by invader success in the absence of the resident community, peaked on infertile soils with low biomass and high community diversity. Net invader success was determined by biotic resistance, consistent with this invader's better performance on infertile soils in unmanipulated conditions. Seed predation added slightly to biotic resistance without qualitatively changing the results. Soil-related genotypic variation in the invader also did not affect the results. Synthesis. In natural systems, diversity may be correlated with invasibility and yet have no effect on either biotic or abiotic resistance to invasion. More generally, the environmental causes of variation in diversity should not be overlooked when considering the potential functional consequences of diversity.

  14. Causes of Forbush decreases and other cosmic ray variations

    Science.gov (United States)

    Barouch, E.; Burlaga, L. F.

    1975-01-01

    The relationship between neutron monitor variations and the intensity variations of the interplanetary magnetic field is studied by using Deep River data and Imp series satellite data. In over 80% of the cases studied in 1968, identifiable depressions of the cosmic ray intensity are associated with magnetic field enhancements of several hours duration and intensity above 10 gamma. Conversely, almost every magnetic field enhancement has an identifiable effect (though not necessarily a marked depression) on the cosmic ray intensity. Perpendicular gradient drifts are suggested as one possible mechanism producing the individual decreases, and some ideas on the recovery processes are presented. Long-lasting Forbush decreases are found to be the consequence of the action of several successive magnetic field enhancements. Evidence is presented that indicates that most of these enhancements are caused by the steepening of streams in interplanetary space.

  15. Causes of snow instability variations at the basin scale

    Science.gov (United States)

    Reuter, Benjamin; Richter, Bettina; Schweizer, Jürg

    2016-04-01

    The alpine snow cover accumulates layers during characteristic meteorological events. The so formed stratigraphic features of the snowpack are known to influence avalanche release processes, such as failure initiation or crack propagation. Synoptic scale meteorological processes are altered by the underlying terrain, which causes micro-meteorological differences at smaller scales, such as the basin scale, for instance. Such micro-meteorological effects of complex snow surfaces were successfully modeled suggesting that the time is ripe to investigate their influence on snow instability. In other words, we aim at identifying the causes of spatial snow instability variations at the scale of a small basin. Over the past years we have compiled several field data sets for a small basin above Davos (Eastern Swiss Alps) covering 400 m by 400 m and consisting of snow penetration resistance profiles collected with the snow micro-penetrometer, terrain data and terrestrial laser scans. Each dataset holds about 150 vertical profiles sampled semi-randomly in the basin and captures the situation of a specific day, hence a particular avalanche situation. At those 150 point measurements the criteria for failure initiation and crack propagation were calculated and their spatial structure was analyzed. Eventually, we were able to model the distribution of snow instability in the basin by external drift kriging. We based the regression models on terrain and snow depth data. Slope aspect was the most prominent driver, but the number of significant covariates depended on the situation. Our results further suggest that the observed differences were caused by external influences possibly due to meteorological forcing as their residual autocorrelation ranges were shorter than the ones of the terrain. Repeating the geostatistical analysis with snow cover model output as covariate data, we were able to identify the causes of the snow instability patterns observed at the basin scale. The most

  16. Cytoplasmic genetic variation and extensive cytonuclear interactions influence natural variation in the metabolome

    DEFF Research Database (Denmark)

    Joseph, Bindu; Corwin, Jason A.; Li, Baohua

    2013-01-01

    affects phenotypic variation. This showed that the cytoplasmic variation had effects similar to, if not larger than, the largest individual nuclear locus. Inclusion of cytoplasmic variation into the genetic model greatly increased the explained phenotypic variation. Cytoplasmic genetic variation...... was a central hub in the epistatic network controlling the plant metabolome. This epistatic influence manifested such that the cytoplasmic background could alter or hide pairwise epistasis between nuclear loci. Thus, cytoplasmic genetic variation plays a central role in controlling natural variation......Understanding genome to phenotype linkages has been greatly enabled by genomic sequencing. However, most genome analysis is typically confined to the nuclear genome. We conducted a metabolomic QTL analysis on a reciprocal RIL population structured to examine how variation in the organelle genomes...

  17. Extent, Causes, and Consequences of Small RNA Expression Variation in Human Adipose Tissue

    OpenAIRE

    Leopold Parts; Hedman, Åsa K.; Sarah Keildson; Knights, Andrew J.; Cei Abreu-Goodger; Martijn van de Bunt; José Afonso Guerra-Assunção; Nenad Bartonicek; Stijn van Dongen; Reedik Mägi; James Nisbet; Amy Barrett; Mattias Rantalainen; Nica, Alexandra C.; Quail, Michael A

    2012-01-01

    Small RNAs are functional molecules that modulate mRNA transcripts and have been implicated in the aetiology of several common diseases. However, little is known about the extent of their variability within the human population. Here, we characterise the extent, causes, and effects of naturally occurring variation in expression and sequence of small RNAs from adipose tissue in relation to genotype, gene expression, and metabolic traits in the MuTHER reference cohort. We profiled the expressio...

  18. The effect of variation in naturalness on phonetic perceptual identification

    Science.gov (United States)

    Remez, Robert E.; Yang, Cynthia Y.; Piorkowski, Rebecca L.; Wissig, Stephanie; Batchelder, Abigail; Nam, Heddy

    2002-05-01

    The relation between apparent naturalness and phonetic identification was assessed in six perceptual tests. A seven-step place-of-articulation series spanning [da] to [ga] was created with speech synthesis approximating the spectra of natural samples. The sensitivity of perceivers to this realization of a place contrast was assessed by estimating the cumulative d' across the series in identification tests. Four variants of this series differing in apparent naturalness were produced by altering the synthesis source function while preserving the center frequency and bandwidth of the formants, and by replicating the gross spectrotemporal patterns with time-varying sinusoids. In addition to calibrating perceivers' sensitivity to the place contrast over variation in naturalness, we conducted a naturalness tournament composed of items drawn from the five test series. A correlation of the findings of the naturalness tournament with the measures of phonetic sensitivity offers an index of the effect of variation in naturalness on phonetic perception. This study can resolve the dispute between the classic premise that intelligibility and naturalness are orthogonal attributes of speech perception, and the more recent premise entailed by episodically based accounts of perceptual categorization, that novel instances are identified by virtue of auditory similarity to prior exemplars. [Research supported by NIDCD.

  19. Seasonal and clonal variations in technological and thermal properties of raw Hevea natural rubber

    Science.gov (United States)

    This study was undertaken over a ten-month period, under the environmental conditions within the state of Mato Grosso, Brazil, to evaluate the causes of variation in technological and thermal properties of raw natural rubber from different clones of Hevea brasiliensis (GT 1, PR 255, FX 3864 and RRIM...

  20. Natural transformation and phase variation modulation in Neisseria meningitidis.

    Science.gov (United States)

    Alexander, Heather L; Richardson, Anthony R; Stojiljkovic, Igor

    2004-05-01

    Neisseria meningitidis has evolved the ability to control the expression-state of numerous genes by phase variation. It has been proposed that the process aids this human pathogen in coping with the diversity of microenvironments and host immune systems. Therefore, increased frequencies of phase variation may augment the organism's adaptability and virulence. In this study, we found that DNA derived from various neisserial co-colonizers of the human nasopharynx increased N. meningitidis switching frequencies, indicating that heterologous neisserial DNA modulates phase variation in a transformation-dependent manner. In order to determine whether the effect of heterologous DNA was specific to the Hb receptor, HmbR, we constructed a Universal Rates of Switching cassette (UROS). With this cassette, we demonstrated that heterologous DNA positively affects phase variation throughout the meningococcal genome, as UROS phase variation frequencies were also increased in the presence of neisserial DNA. Overexpressing components of the neisserial mismatch repair system partially alleviated DNA-induced changes in phase variation frequencies, thus implicating mismatch repair titration as a cause of these transformation-dependent increases in switching. The DNA-dependent effect on phase variation was transient and may serve as a mechanism for meningococcal genetic variability that avoids the fitness costs encountered by global mutators.

  1. Exploiting natural variation to identify insect-resistance genes.

    Science.gov (United States)

    Broekgaarden, Colette; Snoeren, Tjeerd A L; Dicke, Marcel; Vosman, Ben

    2011-10-01

    Herbivorous insects are widespread and often serious constraints to crop production. The use of insect-resistant crops is a very effective way to control insect pests in agriculture, and the development of such crops can be greatly enhanced by knowledge on plant resistance mechanisms and the genes involved. Plants have evolved diverse ways to cope with insect attack that has resulted in natural variation for resistance towards herbivorous insects. Studying the molecular genetics and transcriptional background of this variation has facilitated the identification of resistance genes and processes that lead to resistance against insects. With the development of new technologies, molecular studies are not restricted to model plants anymore. This review addresses the need to exploit natural variation in resistance towards insects to increase our knowledge on resistance mechanisms and the genes involved. We will discuss how this knowledge can be exploited in breeding programmes to provide sustainable crop protection against insect pests. Additionally, we discuss the current status of genetic research on insect-resistance genes. We conclude that insect-resistance mechanisms are still unclear at the molecular level and that exploiting natural variation with novel technologies will contribute greatly to the development of insect-resistant crop varieties.

  2. Genetic variation in natural honeybee populations, Apis mellifera capensis

    Science.gov (United States)

    Hepburn, Randall; Neumann, Peter; Radloff, Sarah E.

    2004-09-01

    Genetic variation in honeybee, Apis mellifera, populations can be considerably influenced by breeding and commercial introductions, especially in areas with abundant beekeeping. However, in southern Africa apiculture is based on the capture of wild swarms, and queen rearing is virtually absent. Moreover, the introduction of European subspecies constantly failed in the Cape region. We therefore hypothesize a low human impact on genetic variation in populations of Cape honeybees, Apis mellifera capensis. A novel solution to studying genetic variation in honeybee populations based on thelytokous worker reproduction is applied to test this hypothesis. Environmental effects on metrical morphological characters of the phenotype are separated to obtain a genetic residual component. The genetic residuals are then re-calculated as coefficients of genetic variation. Characters measured included hair length on the abdomen, width and length of wax plate, and three wing angles. The data show for the first time that genetic variation in Cape honeybee populations is independent of beekeeping density and probably reflects naturally occurring processes such as gene flow due to topographic and climatic variation on a microscale.

  3. Heterochrony underpins natural variation in Cardamine hirsuta leaf form

    Science.gov (United States)

    Cartolano, Maria; Pieper, Bjorn; Lempe, Janne; Tattersall, Alex; Huijser, Peter; Tresch, Achim; Darrah, Peter R.; Hay, Angela; Tsiantis, Miltos

    2015-01-01

    A key problem in biology is whether the same processes underlie morphological variation between and within species. Here, by using plant leaves as an example, we show that the causes of diversity at these two evolutionary scales can be divergent. Some species like the model plant Arabidopsis thaliana have simple leaves, whereas others like the A. thaliana relative Cardamine hirsuta bear complex leaves comprising leaflets. Previous work has shown that these interspecific differences result mostly from variation in local tissue growth and patterning. Now, by cloning and characterizing a quantitative trait locus (QTL) for C. hirsuta leaf shape, we find that a different process, age-dependent progression of leaf form, underlies variation in this trait within species. This QTL effect is caused by cis-regulatory variation in the floral repressor ChFLC, such that genotypes with low-expressing ChFLC alleles show both early flowering and accelerated age-dependent changes in leaf form, including faster leaflet production. We provide evidence that this mechanism coordinates leaf development with reproductive timing and may help to optimize resource allocation to the next generation. PMID:26243877

  4. Natural variation of model mutant phenotypes in Ciona intestinalis.

    Directory of Open Access Journals (Sweden)

    Paolo Sordino

    Full Text Available 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.

  5. Natural enemies drive geographic variation in plant defenses.

    Science.gov (United States)

    Züst, Tobias; Heichinger, Christian; Grossniklaus, Ueli; Harrington, Richard; Kliebenstein, Daniel J; Turnbull, Lindsay A

    2012-10-01

    Plants defend themselves against attack by natural enemies, and these defenses vary widely across populations. However, whether communities of natural enemies are a sufficiently potent force to maintain polymorphisms in defensive traits is largely unknown. Here, we exploit the genetic resources of Arabidopsis thaliana, coupled with 39 years of field data on aphid abundance, to (i) demonstrate that geographic patterns in a polymorphic defense locus (GS-ELONG) are strongly correlated with changes in the relative abundance of two specialist aphids; and (ii) demonstrate differential selection by the two aphids on GS-ELONG, using a multigeneration selection experiment. We thereby show a causal link between variation in abundance of the two specialist aphids and the geographic pattern at GS-ELONG, which highlights the potency of natural enemies as selective forces.

  6. The nature of quantitative genetic variation for Drosophila longevity.

    Science.gov (United States)

    Mackay, Trudy F C

    2002-01-01

    Longevity is a typical quantitative trait: the continuous variation in life span observed in natural populations is attributable to genetic variation at multiple quantitative trait loci (QTL), environmental sensitivity of QTL alleles, and truly continuous environmental variation. To begin to understand the genetic architecture of longevity at the level of individual QTL, we have mapped QTL for Drosophila life span that segregate between two inbred strains that were not selected for longevity. A mapping population of 98 recombinant inbred lines (RIL) was derived from these strains, and life span of virgin male and female flies measured under control culture conditions, chronic heat and cold stress, heat shock and starvation stress, and high and low density larval environments. The genotypes of the RIL were determined for polymorphic roo transposable element insertion sites, and life span QTL were mapped using composite interval mapping methods. A minimum of 19 life span QTL were detected by recombination mapping. The life span QTL exhibited strong genotype by sex, genotype by environment, and genotype by genotype (epistatic) interactions. These interactions complicate mapping efforts, but evolutionary theory predicts such properties of segregating QTL alleles. Quantitative deficiency mapping of four longevity QTL detected in the control environment by recombination mapping revealed a minimum of 11 QTL in these regions. Clearly, longevity is a complex quantitative trait. In the future, linkage disequilibrium mapping can be used to determine which candidate genes in a QTL region correspond to the genetic loci affecting variation in life span, and define the QTL alleles at the molecular level.

  7. Environmental and biomedical applications of natural metal stable isotope variations

    Science.gov (United States)

    Bullen, T.D.; Walczyk, T.

    2009-01-01

    etal stable isotopes are now being used to trace metal contaminants in the environment and as indicators of human systemic function where metals play a role. Stable isotope abundance variations provide information about metal sources and the processes affecting metals in complex natural systems, complementing information gained from surrogate tracers, such as metal abundance ratios or biochemical markers of metal metabolism. The science is still in its infancy, but the results of initial studies confirm that metal stable isotopes can provide a powerful tool for forensic and biomedical investigations.

  8. Nature, Nurture and Evolution of Intra-Species Variation in Mosquito Arbovirus Transmission Competence

    Directory of Open Access Journals (Sweden)

    Walter J. Tabachnick

    2013-01-01

    Full Text Available Mosquitoes vary in their competence or ability to transmit arthropod-borne viruses (arboviruses. Many arboviruses cause disease in humans and animals. Identifying the environmental and genetic causes of variation in mosquito competence for arboviruses is one of the great challenges in public health. Progress identifying genetic (nature and environmental (nurture factors influencing mosquito competence for arboviruses is reviewed. There is great complexity in the various traits that comprise mosquito competence. The complex interactions between environmental and genetic factors controlling these traits and the factors shaping variation in Nature are largely unknown. The norms of reaction of specific genes influencing competence, their distributions in natural populations and the effects of genetic polymorphism on phenotypic variation need to be determined. Mechanisms influencing competence are not likely due to natural selection because of the direct effects of the arbovirus on mosquito fitness. More likely the traits for mosquito competence for arboviruses are the effects of adaptations for other functions of these competence mechanisms. Determining these other functions is essential to understand the evolution and distributions of competence for arboviruses. This information is needed to assess risk from mosquito-borne disease, predict new mosquito-arbovirus systems, and provide novel strategies to mitigate mosquito-borne arbovirus transmission.

  9. Nature, nurture and evolution of intra-species variation in mosquito arbovirus transmission competence.

    Science.gov (United States)

    Tabachnick, Walter J

    2013-01-11

    Mosquitoes vary in their competence or ability to transmit arthropod-borne viruses (arboviruses). Many arboviruses cause disease in humans and animals. Identifying the environmental and genetic causes of variation in mosquito competence for arboviruses is one of the great challenges in public health. Progress identifying genetic (nature) and environmental (nurture) factors influencing mosquito competence for arboviruses is reviewed. There is great complexity in the various traits that comprise mosquito competence. The complex interactions between environmental and genetic factors controlling these traits and the factors shaping variation in Nature are largely unknown. The norms of reaction of specific genes influencing competence, their distributions in natural populations and the effects of genetic polymorphism on phenotypic variation need to be determined. Mechanisms influencing competence are not likely due to natural selection because of the direct effects of the arbovirus on mosquito fitness. More likely the traits for mosquito competence for arboviruses are the effects of adaptations for other functions of these competence mechanisms. Determining these other functions is essential to understand the evolution and distributions of competence for arboviruses. This information is needed to assess risk from mosquito-borne disease, predict new mosquito-arbovirus systems, and provide novel strategies to mitigate mosquito-borne arbovirus transmission.

  10. Responses of natural runoff to recent climatic variations in the Yellow River basin, China

    Science.gov (United States)

    Tang, Y.; Tang, Q.; Tian, F.; Zhang, Z.; Liu, G.

    2013-11-01

    The zero-flow phenomenon appeared frequently in the lower reaches of the Yellow River in China in the 1990s, whereas it has almost disappeared in recent years. The disappearance of the zero-flow phenomenon should be mainly attributed to the recent water management practices. However, little is known about the effects of recent climatic variations on natural runoff. In this study, we investigated the impacts of climatic variations on natural runoff above the Huayuankou station. The results indicate that there was little increase in precipitation, but substantial recovery of natural runoff in the recent period (2003-2011) compared with the low-flow period (1991-2002). The recent precipitation was slightly greater (∼2% of the baseline precipitation in 1960-1990) than precipitation in the low-flow period. However, the recent natural runoff was much larger (∼14% baseline runoff) than runoff in the low-flow period. The runoff reduction in the low-flow period was mainly caused by precipitation decrease. In the recent period, precipitation accounted for a runoff reduction (∼21% baseline runoff), whereas net radiation, wind speed, air temperature, and relative humidity accounted for a runoff increase (∼7.5% baseline runoff). The spatial pattern of the climatic variation is a factor influencing the response of runoff to climatic variations. The reduction in runoff induced by precipitation change was offset up to half by the impacts of changes in net radiation and wind speed at most sub-basins in the recent period.

  11. Gravity Variation in Siberia: GRACE Observation and Possible Causes

    Directory of Open Access Journals (Sweden)

    Benjamin Fong Chao

    2011-01-01

    Full Text Available We report the finding, from the GRACE observation, of an increasing trend in the gravity anomaly in Siberia at the rate of up to 0.5 ugal yr-1 during 2003/1 - 2009/12, in the backdrop of a negative anomaly of magnitude on the order of ~-10 mgal. In consideration of the non-uniqueness of the gravitational inverse problem, we examine in some detail the various possible geophysical causes to explain the increasing gravity signal. We find two geophysical mechanisms being the most plausible, namely the melting of permafrost and the GIA post-glacial rebound. We conclude that these two mechanisms cannot be ruled out as causes for the regional gravity increase in Siberia, based on gravity data and in want of ancillary geophysical data in the region. More definitive identification of the contributions of the various causes awaits further studies.

  12. Natural Variation of Molecular and Morphological Gibberellin Responses1[OPEN

    Science.gov (United States)

    Herman, Dorota; Kojima, Mikiko; Van Daele, Twiggy; Sakakibara, Hitoshi

    2017-01-01

    Although phytohormones such as gibberellins are essential for many conserved aspects of plant physiology and development, plants vary greatly in their responses to these regulatory compounds. Here, we use genetic perturbation of endogenous gibberellin levels to probe the extent of intraspecific variation in gibberellin responses in natural accessions of Arabidopsis (Arabidopsis thaliana). We find that these accessions vary greatly in their ability to buffer the effects of overexpression of GA20ox1, encoding a rate-limiting enzyme for gibberellin biosynthesis, with substantial differences in bioactive gibberellin concentrations as well as transcriptomes and growth trajectories. These findings demonstrate a surprising level of flexibility in the wiring of regulatory networks underlying hormone metabolism and signaling. PMID:27879393

  13. Independent natural genetic variation of punishment- versus relief-memory

    Science.gov (United States)

    Appel, Mirjam; Kocabey, Samet; Savage, Sinead; König, Christian

    2016-01-01

    A painful event establishes two opponent memories: cues that are associated with pain onset are remembered negatively, whereas cues that coincide with the relief at pain offset acquire positive valence. Such punishment- versus relief-memories are conserved across species, including humans, and the balance between them is critical for adaptive behaviour with respect to pain and trauma. In the fruit fly, Drosophila melanogaster as a study case, we found that both punishment- and relief-memories display natural variation across wild-derived inbred strains, but they do not covary, suggesting a considerable level of dissociation in their genetic effectors. This provokes the question whether there may be heritable inter-individual differences in the balance between these opponent memories in man, with potential psycho-clinical implications. PMID:28003518

  14. Extensive Natural Variation in Arabidopsis Seed Mucilage Structure

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    Cătălin eVoiniciuc

    2016-06-01

    Full Text Available Hydrated Arabidopsis thaliana seeds are coated by a gelatinous layer called mucilage, which is mainly composed of cell wall polysaccharides. Since mucilage is rich in pectin, its architecture can be visualized with the ruthenium red (RR dye. We screened the seeds of around 280 Arabidopsis natural accessions for variation in mucilage structure, and identified a large number of novel variants that differed from the Col-0 wild-type. Most of the accessions released smaller RR-stained capsules compared to the Col-0 reference. By biochemically characterizing the phenotypes of 25 of these accessions in greater detail, we discovered that distinct changes in polysaccharide structure resulted in gelatinous coatings with a deceptively similar appearance. Monosaccharide composition analysis of total mucilage extracts revealed a remarkable variation (from 50% to 200% of Col-0 levels in the content of galactose and mannose, which are important subunits of heteromannan. In addition, most of the natural variants had altered Pontamine Fast Scarlet 4B staining of cellulose and significantly reduced birefringence of crystalline structures. This indicates that the production or organization of cellulose may be affected by the presence of different amounts of hemicellulose. Although the accessions described in this study were primarily collected from Western Europe, they form five different phenotypic classes based on the combined results of our experiments. This suggests that polymorphisms at multiple loci are likely responsible for the observed mucilage structure. The transcription of MUCILAGE-RELATED10 (MUCI10, which encodes a key enzyme for galactoglucomannan synthesis, was severely reduced in multiple variants that phenocopied the muci10-1 insertion mutant. Although we could not pinpoint any causal polymorphisms in this gene, constitutive expression of fluorescently-tagged MUCI10 proteins complemented the mucilage defects of a muci10-like accession. This leads

  15. Dynamics and distribution of natural and human-caused hypoxia

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    N. N. Rabalais

    2010-02-01

    Full Text Available Water masses can become undersaturated with oxygen when natural processes alone or in combination with anthropogenic processes produce enough organic carbon that is aerobically decomposed faster than the rate of oxygen re-aeration. The dominant natural processes usually involved are photosynthetic carbon production and microbial respiration. The re-supply rate is indirectly related to its isolation from the surface layer. Hypoxic water masses (<2 mg L−1, or approximately 30% saturation can form, therefore, under "natural" conditions, and are more likely to occur in marine systems when the water residence time is extended, water exchange and ventilation are minimal, stratification occurs, and where carbon production and export to the bottom layer are relatively high. Hypoxia has occurred through geological time and naturally occurs in oxygen minimum zones, deep basins, eastern boundary upwelling systems, and fjords.

    Hypoxia development and continuation in many areas of the world's coastal ocean is accelerated by human activities, especially where nutrient loading increased in the Anthropocene. This higher loading set in motion a cascading set of events related to eutrophication. The formation of hypoxic areas has been exacerbated by any combination of interactions that increase primary production and accumulation of organic carbon leading to increased respiratory demand for oxygen below a seasonal or permanent pycnocline. Nutrient loading is likely to increase further as population growth and resource intensification rises, especially with increased dependency on crops using fertilizers, burning of fossil fuels, urbanization, and waste water generation. It is likely that the occurrence and persistence of hypoxia will be even more widespread and have more impacts than presently observed.

    Global climate change will further complicate the causative factors in both natural and human-caused hypoxia. The likelihood of

  16. Natural variation in abiotic stress responsive gene expression and local adaptation to climate in Arabidopsis thaliana.

    Science.gov (United States)

    Lasky, Jesse R; Des Marais, David L; Lowry, David B; Povolotskaya, Inna; McKay, John K; Richards, James H; Keitt, Timothy H; Juenger, Thomas E

    2014-09-01

    Gene expression varies widely in natural populations, yet the proximate and ultimate causes of this variation are poorly known. Understanding how variation in gene expression affects abiotic stress tolerance, fitness, and adaptation is central to the field of evolutionary genetics. We tested the hypothesis that genes with natural genetic variation in their expression responses to abiotic stress are likely to be involved in local adaptation to climate in Arabidopsis thaliana. Specifically, we compared genes with consistent expression responses to environmental stress (expression stress responsive, "eSR") to genes with genetically variable responses to abiotic stress (expression genotype-by-environment interaction, "eGEI"). We found that on average genes that exhibited eGEI in response to drought or cold had greater polymorphism in promoter regions and stronger associations with climate than those of eSR genes or genomic controls. We also found that transcription factor binding sites known to respond to environmental stressors, especially abscisic acid responsive elements, showed significantly higher polymorphism in drought eGEI genes in comparison to eSR genes. By contrast, eSR genes tended to exhibit relatively greater pairwise haplotype sharing, lower promoter diversity, and fewer nonsynonymous polymorphisms, suggesting purifying selection or selective sweeps. Our results indicate that cis-regulatory evolution and genetic variation in stress responsive gene expression may be important mechanisms of local adaptation to climatic selective gradients.

  17. THE MODEL OF IDENTIFICATION OF THE PROBLEM MAIN CAUSE SET OF VARIATION

    Directory of Open Access Journals (Sweden)

    Nenad Miric

    2008-06-01

    Full Text Available The term Lean has been widely used in today's product manufacturing and service delivery environments. In its fundamental nature the Lean Philosophy continuously strives for elimination of any kind of waste that exists in such environments. There are six basic strategies [1] related to the Lean Philosophy: Workplace Safety & Order & Cleanliness, JIT production, Six Sigma Quality, Empowered Teams, Visual Management and Pursuit of Perfection. On the journey of sustaining the lean supporting strategies there are many problems, or opportunities as Lean Practitioners call them. The value of some strategies highly depends on the efficiency of the problem solving techniques used to overcome the emerging issues. JIT production is difficult to imagine without a system that supports a high level of operational readiness with equipment uptime above 98%. Six Sigma level of quality, even when built into a product or system design, still undergoes the challenges of day to day operations and the variability brought with it. This variability is the source of waste and lean systems culture strives for continuous reduction of it. Empowered Teams properly trained to recognize the real cause of the problems and their Pursuit of Perfection culture are one of the corner stones of Lean Philosophy sustainability. Their ability to work with Problem Solvers and understand the difference between the "cure of the symptoms" approach versus "problem root cause identification" is one of the distinctions between Lean and Mass operations. Among the series of Statistical Engineering To ols this paper will show one of the techniques that proved to be powerful in the identification of the Set of Variation that contains the Main Cause of the new problems that arise in daily operations. This technique is called Multi - Vari. Multi - Vari is th e statistical engineering method used to analyze the set of data acquired in an organized manner. The set could be analyzed graphically or

  18. Causes of variation in fatty acid content and composition in grass and maize silages

    NARCIS (Netherlands)

    Khan, N.A.; Cone, J.W.; Fievez, V.; Hendriks, W.H.

    2012-01-01

    The aim of this study was to quantify the variation in fatty acid (FA) content and composition in grass and maize silages and to identify key management factors during plant growth and the ensiling process that cause this variation. Samples of grass (n = 101) and maize (n = 96) silages were randomly

  19. Small RNA-directed epigenetic natural variation in Arabidopsis thaliana.

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    Jixian Zhai

    2008-04-01

    Full Text Available Progress in epigenetics has revealed mechanisms that can heritably regulate gene function independent of genetic alterations. Nevertheless, little is known about the role of epigenetics in evolution. This is due in part to scant data on epigenetic variation among natural populations. In plants, small interfering RNA (siRNA is involved in both the initiation and maintenance of gene silencing by directing DNA methylation and/or histone methylation. Here, we report that, in the model plant Arabidopsis thaliana, a cluster of approximately 24 nt siRNAs found at high levels in the ecotype Landsberg erecta (Ler could direct DNA methylation and heterochromatinization at a hAT element adjacent to the promoter of FLOWERING LOCUS C (FLC, a major repressor of flowering, whereas the same hAT element in ecotype Columbia (Col with almost identical DNA sequence, generates a set of low abundance siRNAs that do not direct these activities. We have called this hAT element MPF for Methylated region near Promoter of FLC, although de novo methylation triggered by an inverted repeat transgene at this region in Col does not alter its FLC expression. DNA methylation of the Ler allele MPF is dependent on genes in known silencing pathways, and such methylation is transmissible to Col by genetic crosses, although with varying degrees of penetrance. A genome-wide comparison of Ler and Col small RNAs identified at least 68 loci matched by a significant level of approximately 24 nt siRNAs present specifically in Ler but not Col, where nearly half of the loci are related to repeat or TE sequences. Methylation analysis revealed that 88% of the examined loci (37 out of 42 were specifically methylated in Ler but not Col, suggesting that small RNA can direct epigenetic differences between two closely related Arabidopsis ecotypes.

  20. The Non-Homologous Nature of Solar Diameter Variations

    CERN Document Server

    Sofia, S; Demarque, P; Li, L; Thuillier, G; Sofia, Sabatino; Basu, Sarbani; Demarque, Pierre; Li, Linghuai; Thuillier, Gerard

    2005-01-01

    We show in this paper that the changes of the solar diameter in response to variations of large scale magnetic fields and turbulence are not homologous. For the best current model, the variation at the photospheric level is over 1000 times larger than the variation at a depth of 5 Mm, which is about the level at which f-mode solar oscillations determine diameter variations. This model is supported by observations that indicate larger diameter changes for high degree f-modes than for low degree f-modes, since energy of the former are concentrated at shallower layers than the latter.

  1. The causes of variation in learning and behavior: Why individual differences matter

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    Bruno eSauce

    2013-07-01

    Full Text Available In a seminal paper written five decades ago, Cronbach discussed the two highly distinct approaches to scientific psychology: experimental and correlational. Today, although these two approaches are fruitfully implemented and embraced across some fields of psychology, this synergy is largely absent from other areas, such as in the study of learning and behavior. Both Tolman and Hull, in a rare case of agreement, stated that the correlational approach held little promise for the understanding of behavior. Interestingly, this dismissal of the study of individual differences was absent in the biologically-oriented branches of behavior analysis, namely, behavioral genetics and ethology. Here we propose that the distinction between causation and causes of variation (with its origins in the field of genetics reveal the potential value of the correlational approach in understanding the full complexity of learning and behavior. Although the experimental approach can illuminate the causal variables that modulate learning, the analysis of individual differences can elucidate how much and in which way variables interact to support variations in learning in complex natural environments. For example, understanding that a past experience with a stimulus influences its associability provides little insight into how individual predispositions interact to modulate this influence on associability. In this new light, we discuss examples from studies of individual differences in animals’ performance in the Morris Water Maze and from our own work on individual differences in general intelligence in mice. These studies illustrate that, opposed to what Underwood famously suggested, studies of individual differences can do much more to psychology than merely providing preliminary indications of cause-effect relationships.

  2. Empirical Study of the Origins and Causes of Variation Orders in Building Projects

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    Dr. Simon Eigbe

    2016-10-01

    Full Text Available Variations or changes to construction plans have been identified as a major problem in construction projects. Variations have adverse impact on project delivery. Effective management of variations, therefore, is critical to accomplishing project objectives; and this commences with identifying the sources and causes of variations. This paper presents the results of a study of the origins and causes of variation orders in building projects within the Federal Government of Nigeria (FGN: Ministries, Departments, and Agencies (MDGs. Extensive review of relevant literature has been provided. The methodology adopted involved the use of structured questionnaires administered on the MDGs ensuring a fair representation of the geo-political zones of the country. Use was made of field assistants to facilitate the administration of questionnaires. An ex-post facto research design was also employed in the data gathering. Analysis of data was done using descriptive and inferential statistics. The results reveal that variation orders are common in building projects. The client was shown to be the most frequently involved origin agent of variation orders as a result of inadequate or unclear brief, and change in plan or scope. The study concludes with recommendations that project planning; and engagement of project officers are effective means of formulating clear project briefs in order to minimize variation orders and enhance project performance

  3. Extent, causes, and consequences of small RNA expression variation in human adipose tissue.

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    Leopold Parts

    Full Text Available Small RNAs are functional molecules that modulate mRNA transcripts and have been implicated in the aetiology of several common diseases. However, little is known about the extent of their variability within the human population. Here, we characterise the extent, causes, and effects of naturally occurring variation in expression and sequence of small RNAs from adipose tissue in relation to genotype, gene expression, and metabolic traits in the MuTHER reference cohort. We profiled the expression of 15 to 30 base pair RNA molecules in subcutaneous adipose tissue from 131 individuals using high-throughput sequencing, and quantified levels of 591 microRNAs and small nucleolar RNAs. We identified three genetic variants and three RNA editing events. Highly expressed small RNAs are more conserved within mammals than average, as are those with highly variable expression. We identified 14 genetic loci significantly associated with nearby small RNA expression levels, seven of which also regulate an mRNA transcript level in the same region. In addition, these loci are enriched for variants significant in genome-wide association studies for body mass index. Contrary to expectation, we found no evidence for negative correlation between expression level of a microRNA and its target mRNAs. Trunk fat mass, body mass index, and fasting insulin were associated with more than twenty small RNA expression levels each, while fasting glucose had no significant associations. This study highlights the similar genetic complexity and shared genetic control of small RNA and mRNA transcripts, and gives a quantitative picture of small RNA expression variation in the human population.

  4. Extent, Causes, and Consequences of Small RNA Expression Variation in Human Adipose Tissue

    Science.gov (United States)

    Knights, Andrew J.; Abreu-Goodger, Cei; van de Bunt, Martijn; Guerra-Assunção, José Afonso; Bartonicek, Nenad; van Dongen, Stijn; Mägi, Reedik; Nisbet, James; Barrett, Amy; Rantalainen, Mattias; Nica, Alexandra C.; Quail, Michael A.; Small, Kerrin S.; Glass, Daniel; Enright, Anton J.; Winn, John; Deloukas, Panos; Dermitzakis, Emmanouil T.; McCarthy, Mark I.; Spector, Timothy D.; Durbin, Richard; Lindgren, Cecilia M.

    2012-01-01

    Small RNAs are functional molecules that modulate mRNA transcripts and have been implicated in the aetiology of several common diseases. However, little is known about the extent of their variability within the human population. Here, we characterise the extent, causes, and effects of naturally occurring variation in expression and sequence of small RNAs from adipose tissue in relation to genotype, gene expression, and metabolic traits in the MuTHER reference cohort. We profiled the expression of 15 to 30 base pair RNA molecules in subcutaneous adipose tissue from 131 individuals using high-throughput sequencing, and quantified levels of 591 microRNAs and small nucleolar RNAs. We identified three genetic variants and three RNA editing events. Highly expressed small RNAs are more conserved within mammals than average, as are those with highly variable expression. We identified 14 genetic loci significantly associated with nearby small RNA expression levels, seven of which also regulate an mRNA transcript level in the same region. In addition, these loci are enriched for variants significant in genome-wide association studies for body mass index. Contrary to expectation, we found no evidence for negative correlation between expression level of a microRNA and its target mRNAs. Trunk fat mass, body mass index, and fasting insulin were associated with more than twenty small RNA expression levels each, while fasting glucose had no significant associations. This study highlights the similar genetic complexity and shared genetic control of small RNA and mRNA transcripts, and gives a quantitative picture of small RNA expression variation in the human population. PMID:22589741

  5. Natural variation in biomarkers indicating mastitis in healthy cows

    DEFF Research Database (Denmark)

    Åkerstedt, Maria; Forsbäck, Linda; Larsen, Torben

    2010-01-01

    Dairy herds are expanding and, with increasing numbers of animals in each herd, there is a need for automatic recording of indicators in milk in order to detect mastitis, inflammation of the udder. A number of biomarkers for mastitis have been suggested over the years. Mastitis usually occurs...... in one of the four udder quarters and since it is now possible to milk each udder quarter separately in automated milking systems, it is important to evaluate the normal variation in the biomarkers at udder quarter level. This study evaluated the normal variations between milkings for some biomarkers...... in clinically healthy cows, determined by repeated somatic cell count and bacteriological analysis. The biomarkers studied were serum amyloid A (SAA), haptoglobin (Hp), lactate dehydrogenase (LDH), N-acetyl-β-d-glucosaminidase (NAGase) and alkaline phosphatase (AP), parameters that have been suggested...

  6. Causes and consequences of variation in leaf mass per area (LMA): a meta-analysis

    NARCIS (Netherlands)

    Poorter, H.; Niinemets, U.; Poorter, L.; Wright, I.J.; Villar, H.

    2009-01-01

    Here, we analysed a wide range of literature data on the leaf dry mass per unit area (LMA). In nature, LMA varies more than 100-fold among species. Part of this variation (c. 35%) can be ascribed to differences between functional groups, with evergreen species having the highest LMA, but most of the

  7. Sensitivity Analysis on Variation of Vane Natural Frequency of a Typical Aero Engine Impeller

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    Selwyn Anbarasan

    2015-08-01

    Full Text Available Centrifugal compressors are widely used in small and medium class turbo shaft and turbo prop aero engines. Inevitably the variation in the manufacturing process will lead to variation in natural frequency of blade vanes in an impeller which usually termed as Mistuning. The variation in natural frequency will increase the forced frequency response of the vanes than the tuned vanes. In-service deterioration of vanes dimension due to erosion, corrosion and FOD also adds to further variation in natural frequency. The amplification factor of the response will lead to reduced HCF life of the vanes than the tuned vanes. It is important for the designer to envisage the variation of natural frequency of the vanes to estimate the life of the impeller to avoid premature failure. This also helps in monitoring the health of the impeller during service. This paper deals with prediction of the effects of manufacturing/geometry variation and variation in material properties on impeller vane natural frequency of a turbo shaft engine. FEM model is created to accommodate the geometry variation of the impeller. The parameters influencing the natural frequency are varied and its corresponding variation in frequency is predicted. Several conditions are also simulated and sensitivity analysis is carried out with the above result to predict the order of influencing parameters. Influencing parameters are ranked and the most influencing parameter is found to be the Young’s Modulus of the material for this case of impeller. Maximum influencing parameter Young’s modulus contributes to 5.8% variation and the least contributing factor density to 0.6% variation in natural frequency. This result enables the designer to forecast the possible range of natural frequencies in the design phase, so that he can limit the analysis to predict the response due to mistuning to the estimated range of frequencies.

  8. Natural variation in the thermotolerance of neural function and behavior due to a cGMP-dependent protein kinase.

    Directory of Open Access Journals (Sweden)

    Ken Dawson-Scully

    Full Text Available Although it is acknowledged that genetic variation contributes to individual differences in thermotolerance, the specific genes and pathways involved and how they are modulated by the environment remain poorly understood. We link natural variation in the thermotolerance of neural function and behavior in Drosophila melanogaster to the foraging gene (for, which encodes a cGMP-dependent protein kinase (PKG as well as to its downstream target, protein phosphatase 2A (PP2A. Genetic and pharmacological manipulations revealed that reduced PKG (or PP2A activity caused increased thermotolerance of synaptic transmission at the larval neuromuscular junction. Like synaptic transmission, feeding movements were preserved at higher temperatures in larvae with lower PKG levels. In a comparative assay, pharmacological manipulations altering thermotolerance in a central circuit of Locusta migratoria demonstrated conservation of this neuroprotective pathway. In this circuit, either the inhibition of PKG or PP2A induced robust thermotolerance of neural function. We suggest that PKG and therefore the polymorphism associated with the allelic variation in for may provide populations with natural variation in heat stress tolerance. for's function in behavior is conserved across most organisms, including ants, bees, nematodes, and mammals. PKG's role in thermotolerance may also apply to these and other species. Natural variation in thermotolerance arising from genes involved in the PKG pathway could impact the evolution of thermotolerance in natural populations.

  9. Natural Variation in the Thermotolerance of Neural Function and Behavior due to a cGMP-Dependent Protein Kinase

    Science.gov (United States)

    Dawson-Scully, Ken; Armstrong, Gary A.B.; Kent, Clement; Robertson, R. Meldrum; Sokolowski, Marla B.

    2007-01-01

    Although it is acknowledged that genetic variation contributes to individual differences in thermotolerance, the specific genes and pathways involved and how they are modulated by the environment remain poorly understood. We link natural variation in the thermotolerance of neural function and behavior in Drosophila melanogaster to the foraging gene (for, which encodes a cGMP-dependent protein kinase (PKG)) as well as to its downstream target, protein phosphatase 2A (PP2A). Genetic and pharmacological manipulations revealed that reduced PKG (or PP2A) activity caused increased thermotolerance of synaptic transmission at the larval neuromuscular junction. Like synaptic transmission, feeding movements were preserved at higher temperatures in larvae with lower PKG levels. In a comparative assay, pharmacological manipulations altering thermotolerance in a central circuit of Locusta migratoria demonstrated conservation of this neuroprotective pathway. In this circuit, either the inhibition of PKG or PP2A induced robust thermotolerance of neural function. We suggest that PKG and therefore the polymorphism associated with the allelic variation in for may provide populations with natural variation in heat stress tolerance. for's function in behavior is conserved across most organisms, including ants, bees, nematodes, and mammals. PKG's role in thermotolerance may also apply to these and other species. Natural variation in thermotolerance arising from genes involved in the PKG pathway could impact the evolution of thermotolerance in natural populations. PMID:17712421

  10. The second parity sow : causes and consequences of variation in reproductive performance

    NARCIS (Netherlands)

    Hoving, L.L.

    2012-01-01

    Many sows show reduced litter sizes in their second parity compared with their first parity. The aim of the current thesis was to describe causes and consequences of variation on second parity reproductive performance and to evaluate if feeding strategies during early gestation affect reproductive p

  11. A global health problem caused by arsenic from natural sources

    Energy Technology Data Exchange (ETDEWEB)

    Ng, J.C.; Wang, J.P.; Shraim, A. [University of Queensland, Brisbane, Qld. (Australia). National Research Center for Environmental Toxicology

    2003-09-01

    Arsenic is a carcinogen to both humans and animals. Arsenicals have been associated with cancers of the skin, lung, and bladder. Clinical manifestations of chronic arsenic poisoning include non-cancer end point of hyper- and hypo-pigmentation, keratosis, hypertension, cardiovascular diseases and diabetes. Epidemiological evidence indicates that arsenic concentration exceeding 50 {mu}g l{sup -1} in the drinking water is not public health protective. The current WHO recommended guideline value for arsenic in drinking water is 10 {mu}g l{sup -1}, whereas many developing countries are still having a value of 50 {mu}g 1{sup -1}. It has been estimated that tens of millions of people are at risk exposing to excessive levels of arsenic from both contaminated water and arsenic-bearing coal from natural sources. The global health implication and possible intervention strategies were also discussed in this review article.

  12. Natural variation in folate levels among tomato (Solanum lycopersicum) accessions.

    Science.gov (United States)

    Upadhyaya, Pallawi; Tyagi, Kamal; Sarma, Supriya; Tamboli, Vajir; Sreelakshmi, Yellamaraju; Sharma, Rameshwar

    2017-02-15

    Folate content was estimated in tomato (Solanum lycopersicum) accessions using microbiological assay (MA) and by LC-MS. The MA revealed that in red-ripe fruits folate levels ranged from 4 to 60μg/100g fresh weight. The LC-MS estimation of red-ripe fruits detected three folate forms, 5-CH3-THF, 5-CHO-THF, 5,10-CH(+)THF and folate levels ranged from 14 to 46μg/100g fresh weight. In mature green and red ripe fruit, 5-CH3-THF was the most abundant folate form. Comparison of LC-MS with MA revealed that MA inaccurately estimates folate levels. The accumulation of folate forms and their distribution varied among accessions. The single nucleotide polymorphism was examined in the key genes of the folate pathway to understand its linkage with folate levels. Despite the significant variation in folate levels among tomato accessions, little polymorphism was found in folate biosynthesis genes. Our results indicate that variation in folate level is governed by a more complex regulation at cellular homeostasis level.

  13. Rare cause of natural death in forensic setting: hemophagocytic syndrome.

    Science.gov (United States)

    Ondruschka, B; Habeck, J-O; Hädrich, C; Dreßler, J; Bayer, R

    2016-05-01

    We report about the case of a sudden unexpected death of a 25-year-old male suffering from infectious disease. An autopsy was ordered with no final premortem diagnosis. Microscopic and microbiological examination revealed a pneumococcal bronchopneumonia and hemophagocytic lesions in the bone marrow. After integrating clinical and autopsy reports as well as additional postmortem investigations, the cause of death was found to be infectious-triggered hemophagocytic syndrome (HPS) with a final cytokine storm. This seems to be the first reported fatal case of a reactive form of HPS associated to Streptococcus pneumoniae to the best of our knowledge. HPS is a dangerous hyperinflammation with highly characteristic, but nonspecific, laboratory findings and symptoms. Autopsies in such cases must be carefully performed and include systematic tissue sampling done by an experienced pathologist.

  14. Natural genetic variation in Arabidopsis for responsiveness to plant growth-promoting rhizobacteria.

    Science.gov (United States)

    Wintermans, Paul C A; Bakker, Peter A H M; Pieterse, Corné M J

    2016-04-01

    The plant growth-promoting rhizobacterium (PGPR) Pseudomonas simiae WCS417r stimulates lateral root formation and increases shoot growth in Arabidopsis thaliana (Arabidopsis). These plant growth-stimulating effects are partly caused by volatile organic compounds (VOCs) produced by the bacterium. Here, we performed a genome-wide association (GWA) study on natural genetic variation in Arabidopsis for the ability to profit from rhizobacteria-mediated plant growth-promotion. To this end, 302 Arabidopsis accessions were tested for root architecture characteristics and shoot fresh weight in response to exposure to WCS417r. Although virtually all Arabidopsis accessions tested responded positively to WCS417r, there was a large variation between accessions in the increase in shoot fresh weight, the extra number of lateral roots formed, and the effect on primary root length. Correlation analyses revealed that the bacterially-mediated increase in shoot fresh weight is related to alterations in root architecture. GWA mapping for WCS417r-stimulated changes in root and shoot growth characteristics revealed 10 genetic loci highly associated with the responsiveness of Arabidopsis to the plant growth-promoting activity of WCS417r. Several of the underlying candidate genes have been implicated in important plant growth-related processes. These results demonstrate that plants possess natural genetic variation for the capacity to profit from the plant growth-promoting function of a beneficial rhizobacterium in their rhizosphere. This knowledge is a promising starting point for sustainable breeding strategies for future crops that are better able to maximize profitable functions from their root microbiome.

  15. Natural variations in the rhenium isotopic composition of meteorites

    Science.gov (United States)

    Liu, R.; Hu, L.; Humayun, M.

    2017-03-01

    Rhenium is an important element with which to test hypotheses of isotope variation. Historically, it has been difficult to precisely correct the instrumental mass bias in thermal ionization mass spectrometry. We used W as an internal standard to correct mass bias on the MC-ICP-MS, and obtained the first precise δ187Re values ( ±0.02‰, 2SE) for iron meteorites and chondritic metal. Relative to metal from H chondrites, IVB irons are systematically higher in δ187Re by 0.14 ‰. δ187Re for other irons are similar to H chondritic metal, although some individual samples show significant isotope fractionation. Since 185Re has a high neutron capture cross section, the effect of galactic cosmic-ray (GCR) irradiation on δ187Re was examined using correlations with Pt isotopes. The pre-GCR irradiation δ187Re for IVB irons is lower, but the difference in δ187Re between IVB irons and other meteoritic metal remains. Nuclear volume-dependent fractionation for Re is about the right magnitude near the melting point of iron, but because of the refractory and compatible character of Re, a compelling explanation in terms of mass-dependent fractionation is elusive. The magnitude of a nucleosynthetic s-process deficit for Re estimated from Mo and Ru isotopes is essentially unresolvable. Since thermal processing reduced nucleosynthetic effects in Pd, it is conceivable that Re isotopic variations larger than those in Mo and Ru may be present in IVBs since Re is more refractory than Mo and Ru. Thus, the Re isotopic difference between IVBs and other irons or chondritic metal remains unexplained.

  16. Present day sea level changes: observation and causes; Les variations actuelles du niveau de la mer: observations et causes

    Energy Technology Data Exchange (ETDEWEB)

    Lombard, A

    2005-11-15

    Whereas sea level has changed little over the last 2000 years, it has risen at a rate of about 2 mm/year during the 20. century. This unexpected sea level rise has been attributed to the anthropogenic global warming, recorded over several decades. Sea level variations have been measured globally and precisely for about 12 years due to satellite altimeter missions Topex/Poseidon and Jason-1. These observations indicate a global mean sea level rise of about 3 mm/year since 1993, a value significantly larger than observed during previous decades. Recent observations have allowed us to quantify the various climatic factors contributing to observed sea level change: thermal expansion of sea water due to ocean warming, melting of mountain glaciers and ice sheets, and changes in the land water reservoirs. A water budget based on these new observations allows us to partly explain the observed sea level rise. In particular, we show that the thermal expansion explains only 25% of the secular sea level rise as recorded by tide-gauges over the last 50 years, while it contributes about 50% of sea level rise observed over the last decade. Meanwhile, recent studies show that glacier and ice sheet melting could contribute the equivalent of 1 mm/year in sea level rise over the last decade. In addition, the high regional variability of sea level trends revealed by satellite altimetry is mainly due to thermal expansion. There is also an important decadal spatio-temporal variability in the ocean thermal expansion over the last 50 years, which seems to be controlled by natural climate fluctuations. We question for the first time the link between the decadal fluctuations in the ocean thermal expansion and in the land reservoirs, and indeed their climatic contribution to sea level change. Finally a preliminary analysis of GRACE spatial gravimetric observations over the oceans allows us to estimate the seasonal variations in mean sea level due to ocean water mass balance variations

  17. Natural variation and genetic covariance in adult hippocampal neurogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Kempermann, Gerd [Center for Molecular Medicine, Berlin, Germany; Chesler, Elissa J [ORNL; Lu, Lu [University of Tennessee Health Science Center, Memphis; Williams, Robert [University of Tennessee Health Science Center, Memphis; Gage, Fred [Salk Institute for Biological Studies, The, San Diego, CA

    2006-01-01

    Adult hippocampal neurogenesis is highly variable and heritable among laboratory strains of mice. Adult neurogenesis is also remarkably plastic and can be modulated by environment and activity. Here, we provide a systematic quantitative analysis of adult hippocampal neurogenesis in two large genetic reference panels of recombinant inbred strains (BXD and AXB?BXA, n ? 52 strains). We combined data on variation in neurogenesis with a new transcriptome database to extract a set of 190 genes with expression patterns that are also highly variable and that covary with rates of (i) cell proliferation, (ii) cell survival, or the numbers of surviving (iii) new neurons, and (iv) astrocytes. Expression of a subset of these neurogenesis-associated transcripts was controlled in cis across the BXD set. These self-modulating genes are particularly interesting candidates to control neurogenesis. Among these were musashi (Msi1h) and prominin1?CD133 (Prom1), both of which are linked to stem-cell maintenance and division. Twelve neurogenesis-associated transcripts had significant cis-acting quantitative trait loci, and, of these, six had plausible biological association with adult neurogenesis (Prom1, Ssbp2, Kcnq2, Ndufs2, Camk4, and Kcnj9). Only one cis- cting candidate was linked to both neurogenesis and gliogenesis, Rapgef6, a downstream target of ras signaling. The use of genetic reference panels coupled with phenotyping and global transcriptome profiling thus allowed insight into the complexity of the genetic control of adult neurogenesis.

  18. Unused natural variation can lift yield barriers in plant breeding.

    Directory of Open Access Journals (Sweden)

    Amit Gur

    2004-10-01

    Full Text Available Natural biodiversity is an underexploited sustainable resource that can enrich the genetic basis of cultivated plants with novel alleles that improve productivity and adaptation. We evaluated the progress in breeding for increased tomato (Solanum lycopersicum yield using genotypes carrying a pyramid of three independent yield-promoting genomic regions introduced from the drought-tolerant green-fruited wild species Solanum pennellii. Yield of hybrids parented by the pyramided genotypes was more than 50% higher than that of a control market leader variety under both wet and dry field conditions that received 10% of the irrigation water. This demonstration of the breaking of agricultural yield barriers provides the rationale for implementing similar strategies for other agricultural organisms that are important for global food security.

  19. Responses of natural runoff to recent climatic variations in the Yellow River basin, China

    OpenAIRE

    Tang, Y.; Tang, Q.; Tian, F.; Zhang, Z.; G. Liu

    2013-01-01

    The zero-flow phenomenon appeared frequently in the lower reaches of the Yellow River in China in the 1990s, whereas it has almost disappeared in recent years. The disappearance of the zero-flow phenomenon should be mainly attributed to the recent water management practices. However, little is known about the effects of recent climatic variations on natural runoff. In this study, we investigated the impacts of climatic variations on natural runoff above the Huayuankou statio...

  20. Nucleotide variation at the dopa decarboxylase (Ddc) gene in natural populations of Drosophila melanogaster

    Indian Academy of Sciences (India)

    Andrey Tatarenkov; Francisco J. Ayala

    2007-08-01

    We studied nucleotide sequence variation at the gene coding for dopa decarboxylase (Ddc) in seven populations of Drosophila melanogaster. Strength and pattern of linkage disequilibrium are somewhat distinct in the extensively sampled Spanish and Raleigh populations. In the Spanish population, a few sites are in strong positive association, whereas a large number of sites in the Raleigh population are associated nonrandomly but the association is not strong. Linkage disequilibrium analysis shows presence of two groups of haplotypes in the populations, each of which is fairly diverged, suggesting epistasis or inversion polymorphism. There is evidence of two forms of natural selection acting on Ddc. The McDonald–Kreitman test indicates a deficit of fixed amino acid differences between D. melanogaster and D. simulans, which may be due to negative selection. An excess of derived alleles at high frequency, significant according to the -test, is consistent with the effect of hitchhiking. The hitchhiking may have been caused by directional selection downstream of the locus studied, as suggested by a gradual decrease of the polymorphism-to-divergence ratio. Altogether, the Ddc locus exhibits a complicated pattern of variation apparently due to several evolutionary forces. Such a complex pattern may be a result of an unusually high density of functionally important genes.

  1. Seasonal variation in natural recharge of coastal aquifers

    Science.gov (United States)

    Mollema, Pauline N.; Antonellini, Marco

    2013-06-01

    Many coastal zones around the world have irregular precipitation throughout the year. This results in discontinuous natural recharge of coastal aquifers, which affects the size of freshwater lenses present in sandy deposits. Temperature data for the period 1960-1990 from LocClim (local climate estimator) and those obtained from the Intergovernmental Panel on Climate Change (IPCC) SRES A1b scenario for 2070-2100, have been used to calculate the potential evapotranspiration with the Thornthwaite method. Potential recharge (difference between precipitation and potential evapotranspiration) was defined at 12 locations: Ameland (The Netherlands), Auckland and Wellington (New Zealand); Hong Kong (China); Ravenna (Italy), Mekong (Vietnam), Mumbai (India), New Jersey (USA), Nile Delta (Egypt), Kobe and Tokyo (Japan), and Singapore. The influence of variable/discontinuous recharge on the size of freshwater lenses was simulated with the SEAWAT model. The discrepancy between models with continuous and with discontinuous recharge is relatively small in areas where the total annual recharge is low (258-616 mm/year); but in places with Monsoon-dominated climate (e.g. Mumbai, with recharge up to 1,686 mm/year), the difference in freshwater-lens thickness between the discontinuous and the continuous model is larger (up to 5 m) and thus important to consider in numerical models that estimate freshwater availability.

  2. Natural strain variation and antibody neutralization of dengue serotype 3 viruses.

    Directory of Open Access Journals (Sweden)

    Wahala M P B Wahala

    2010-03-01

    Full Text Available Dengue viruses (DENVs are emerging, mosquito-borne flaviviruses which cause dengue fever and dengue hemorrhagic fever. The DENV complex consists of 4 serotypes designated DENV1-DENV4. Following natural infection with DENV, individuals develop serotype specific, neutralizing antibody responses. Monoclonal antibodies (MAbs have been used to map neutralizing epitopes on dengue and other flaviviruses. Most serotype-specific, neutralizing MAbs bind to the lateral ridge of domain III of E protein (EDIII. It has been widely assumed that the EDIII lateral ridge epitope is conserved within each DENV serotype and a good target for vaccines. Using phylogenetic methods, we compared the amino acid sequence of 175 E proteins representing the different genotypes of DENV3 and identified a panel of surface exposed amino acids, including residues in EDIII, that are highly variant across the four DENV3 genotypes. The variable amino acids include six residues at the lateral ridge of EDIII. We used a panel of DENV3 mouse MAbs to assess the functional significance of naturally occurring amino acid variation. From the panel of antibodies, we identified three neutralizing MAbs that bound to EDIII of DENV3. Recombinant proteins and naturally occurring variant viruses were used to map the binding sites of the three MAbs. The three MAbs bound to overlapping but distinct epitopes on EDIII. Our empirical studies clearly demonstrate that the antibody binding and neutralization capacity of two MAbs was strongly influenced by naturally occurring mutations in DENV3. Our data demonstrate that the lateral ridge "type specific" epitope is not conserved between strains of DENV3. This variability should be considered when designing and evaluating DENV vaccines, especially those targeting EDIII.

  3. Genomic instability is associated with natural life span variation in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Hong Qin

    Full Text Available Increasing genomic instability is associated with aging in eukaryotes, but the connection between genomic instability and natural variation in life span is unknown. We have quantified chronological life span and loss-of-heterozygosity (LOH in 11 natural isolates of Saccharomyces cerevisiae. We show that genomic instability increases and mitotic asymmetry breaks down during chronological aging. The age-dependent increase of genomic instability generally lags behind the drop of viability and this delay accounts for approximately 50% of the observed natural variation of replicative life span in these yeast isolates. We conclude that the abilities of yeast strains to tolerate genomic instability co-vary with their replicative life spans. To the best of our knowledge, this is the first quantitative evidence that demonstrates a link between genomic instability and natural variation in life span.

  4. Variations of iron flux and organic carbon remineralization in a subterranean estuary caused by interannual variations in recharge

    Science.gov (United States)

    Roy, Moutusi; Martin, Jonathan B.; Cable, Jaye E.; Smith, Christopher G.

    2013-01-01

    We determine the inter-annual variations in diagenetic reaction rates of sedimentary iron (Fe ) in an east Florida subterranean estuary and evaluate the connection between metal fluxes and recharge to the coastal aquifer. Over the three-year study period (from 2004 to 2007), the amount of Fe-oxides reduced at the study site decreased from 192 g/yr to 153 g/yr and associated organic carbon (OC) remineralization decreased from 48 g/yr to 38 g/yr. These reductions occurred although the Fe-oxide reduction rates remained constant around 1 mg/cm2/yr. These results suggest that changes in flow rates of submarine groundwater discharge (SGD) related to changes in precipitation may be important to fluxes of the diagenetic reaction products. Rainfall at a weather station approximately 5 km from the field area decreased from 12.6 cm/month to 8.4 cm/month from 2004 to 2007. Monthly potential evapotranspiration (PET) calculated from Thornthwaite’s method indicated potential evapotranspiration cycled from about 3 cm/month in the winter to about 15 cm/month in the summer so that net annual recharge to the aquifer decreased from 40 cm in 2004 to -10 cm in 2007. Simultaneously, with the decrease in recharge of groundwater, freshwater SGD decreased by around 20% and caused the originally 25 m wide freshwater seepage face to decrease in width by about 5 m. The smaller seepage face reduced the area under which Fe-oxides were undergoing reductive dissolution. Consequently, the observed decrease in Fe flux is controlled by hydrology of the subterranean estuary. These results point out the need to better understand linkages between temporal variations in diagenetic reactions and changes in flow within subterranean estuaries in order to accurately constrain their contribution to oceanic fluxes of solutes from subterranean estuaries.

  5. Natural variations in xenobiotic-metabolizing enzymes: developing tools for coral monitoring

    Science.gov (United States)

    Rougée, L. R. A.; Richmond, R. H.; Collier, A. C.

    2014-06-01

    The continued deterioration of coral reefs worldwide demonstrates the need to develop diagnostic tools for corals that go beyond general ecological monitoring and can identify specific stressors at sublethal levels. Cellular diagnostics present an approach to defining indicators (biomarkers) that have the potential to reflect the impact of stress at the cellular level, allowing for the detection of intracellular changes in corals prior to outright mortality. Detoxification enzymes, which may be readily induced or inhibited by environmental stressors, present such a set of indicators. However, in order to apply these diagnostic tools for the detection of stress, a detailed understanding of their normal, homeostatic levels within healthy corals must first be established. Herein, we present molecular and biochemical evidence for the expression and activity of major Phase I detoxification enzymes cytochrome P450 (CYP450), CYP2E1, and CYP450 reductase, as well as the Phase II enzymes UDP, glucuronosyltransferase (UGT), β-glucuronidase, glutathione- S-transferase (GST), and arylsulfatase C (ASC) in the coral Pocillopora damicornis. Additionally, we characterized enzyme expression and activity variations over a reproductive cycle within a coral's life history to determine natural endogenous changes devoid of stress exposure. Significant changes in enzyme activity over the coral's natural lunar reproductive cycle were observed for CYP2E1 and CYP450 reductase as well as UGT and GST, while β-glucuronidase and ASC did not fluctuate significantly. The data represent a baseline description of `health' for the expression and activity of these enzymes that can be used toward understanding the impact of environmental stressors on corals. Such knowledge can be applied to address causes of coral reef ecosystem decline and to monitor effectiveness of mitigation strategies. Achieving a better understanding of cause-and-effect relationships between putative stressors and biological

  6. A new insight into the nature of seasonal variations in coordinate time series of GPS sites located near active faults

    Science.gov (United States)

    Trofimenko, Sergey V.; Bykov, Victor G.; Shestakov, Nikolay V.; Grib, Nikolay N.; Takahashi, Hiroaki

    2016-09-01

    This study provides new insights into the nature of seasonal variations in coordinate time series of GPS sites located near active faults and methods of their modeling. Monthly averaged coordinate time series were analyzed for several pairs of collocated GPS sites situated near the active fault intersection area, in close proximity to the central part of the northern boundary of the Amurian plate and the vicinity of the San Andreas Fault zone. It is concluded that the observed seasonal variations are best described by a breather function which is one of the solutions of the well-known sine-Gordon equation. The obtained results suggest that, in this case, the source of seasonal variations may be caused by the appearance of solitary strain waves in the fault intersection system, which may be qualitatively treated as standing waves of compression-extension of the geological medium. Based on statistical testing, the limits of applicability of the suggested model have been established.

  7. Understanding natural cause: children's explanations of how objects and their properties originate.

    Science.gov (United States)

    Gelman, S A; Kremer, K E

    1991-04-01

    An understanding of natural cause includes the realization that events can occur independently of human activity or intentions. It also often entails realizing that causal mechanisms can be nonobservable or nonobvious. The present research investigated to what extent children ages 4-7 have developed a concept of natural cause. Study 1 examined children's understandings of object origins (e.g., how the sun began); Study 2 probed children's causal understandings of object behaviors and properties (e.g., why rabbits hop and have long ears). In both studies, children by age 4 were sensitive to the natural kind-artifact distinction in their explanations. They mentioned human intervention for human-made artifacts but rarely for naturally occurring things. Moreover, subjects at all ages were able to identify specific kinds of natural cause, including intrinsic causes (such as growth) and inborn nature. Finally, subjects understood the link between nonobvious, internal parts and self-generated activity (e.g., that bones are important for the flight of a bird). Altogether, these results suggest that even preschool children realize that natural causes exist. They contradict Piaget's characterization of young children as artificialistic (believing that naturally occurring things are created by people) and as focused on observable properties.

  8. Evolutionary Influenced Interaction Pattern as Indicator for the Investigation of Natural Variants Causing Nephrogenic Diabetes Insipidus.

    Science.gov (United States)

    Grunert, Steffen; Labudde, Dirk

    2015-01-01

    The importance of short membrane sequence motifs has been shown in many works and emphasizes the related sequence motif analysis. Together with specific transmembrane helix-helix interactions, the analysis of interacting sequence parts is helpful for understanding the process during membrane protein folding and in retaining the three-dimensional fold. Here we present a simple high-throughput analysis method for deriving mutational information of interacting sequence parts. Applied on aquaporin water channel proteins, our approach supports the analysis of mutational variants within different interacting subsequences and finally the investigation of natural variants which cause diseases like, for example, nephrogenic diabetes insipidus. In this work we demonstrate a simple method for massive membrane protein data analysis. As shown, the presented in silico analyses provide information about interacting sequence parts which are constrained by protein evolution. We present a simple graphical visualization medium for the representation of evolutionary influenced interaction pattern pairs (EIPPs) adapted to mutagen investigations of aquaporin-2, a protein whose mutants are involved in the rare endocrine disorder known as nephrogenic diabetes insipidus, and membrane proteins in general. Furthermore, we present a new method to derive new evolutionary variations within EIPPs which can be used for further mutagen laboratory investigations.

  9. Reaction wood – a key cause of variation in cell wall recalcitrance in willow

    Directory of Open Access Journals (Sweden)

    Brereton Nicholas JB

    2012-11-01

    the nature of RW variation, could provide novel targets for genetic modification for improved biofuel feedstocks.

  10. The causes of stemflow variation in three semi-arid growing species of northeastern Mexico

    Science.gov (United States)

    Návar, José

    1993-05-01

    This study was conducted to determine the role of some plant parameters on stemflow generation. Stemflow measurements in individual shrubs of three semi-arid growing species ( Diospyrus texana, Acacia farnesiana and Prosopis laevigata) were carried out under natural and simulated rainfall conditions in northeastern Mexico. Stemflow coefficients for individual shrubs were developed. The analysis of variance showed a significant difference among the species for both natural and simulated rainfall conditions. The multiple linear models suggested that the number of branches and position on the canopy, instead of total projected branch area, controls stemflow. There were also suggestions that bark roughness, leaf and twig position may also explain some of the interspecific stemflow variation. This contribution was suggested by an introduced funnelling ratio.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  13. Causes and consequences of variation in leaf mass per area (LMA): a meta-analysis.

    Science.gov (United States)

    Poorter, Hendrik; Niinemets, Ulo; Poorter, Lourens; Wright, Ian J; Villar, Rafael

    2009-01-01

    Here, we analysed a wide range of literature data on the leaf dry mass per unit area (LMA). In nature, LMA varies more than 100-fold among species. Part of this variation (c. 35%) can be ascribed to differences between functional groups, with evergreen species having the highest LMA, but most of the variation is within groups or biomes. When grown in the same controlled environment, leaf succulents and woody evergreen, perennial or slow-growing species have inherently high LMA. Within most of the functional groups studied, high-LMA species show higher leaf tissue densities. However, differences between evergreen and deciduous species result from larger volumes per area (thickness). Response curves constructed from experiments under controlled conditions showed that LMA varied strongly with light, temperature and submergence, moderately with CO2 concentration and nutrient and water stress, and marginally under most other conditions. Functional groups differed in the plasticity of LMA to these gradients. The physiological regulation is still unclear, but the consequences of variation in LMA and the suite of traits interconnected with it are strong. This trait complex is an important factor determining the fitness of species in their environment and affects various ecosystem processes.

  14. Natural selection and genital variation: a role for the environment, parasites and sperm ageing?

    Science.gov (United States)

    Reinhardt, Klaus

    2010-01-01

    Male genitalia are more variable between species (and populations) than other organs, and are more morphologically complex in polygamous compared to monogamous species. Therefore, sexual selection has been put forward as the major explanation of genital variation and complexity, in particular cryptic female choice for male copulatory courtship. As cryptic female choice is based on differences between males it is somewhat paradoxical that there is such low within-species variation in male genitalia that they are a prime morphological identification character for animal species. Processes other than sexual selection may also lead to genitalia variation but they have recently become neglected. Here I focus on pleiotropy and natural selection and provide examples how they link genitalia morphology with genital environments. Pleiotropy appears to be important because most studies that specifically tested for pleiotropic effects on genital morphology found them. Natural selection likely favours certain genital morphology over others in various environments, as well as by reducing re-infection with sexually transmitted diseases or reducing the likelihood of fertilisation with aged sperm. Both pleiotropy and natural selection differ locally and between species so may contribute to local variation in genitalia and sometimes variation between monogamous and polygamous species. Furthermore, the multitude of genital environments will lead to a multitude of genital functions via natural selection and pleiotropy, and may also contribute to explaining the complexity of genitalia.

  15. Physiological variation of retinal layer thickness is not caused by hydration: a randomised trial.

    Science.gov (United States)

    Balk, Lisanne J; Oberwahrenbrock, Timm; Uitdehaag, Bernard M J; Petzold, Axel

    2014-09-15

    There is evidence for physiological variation of retinal thicknesses as determined by optical coherence tomography (OCT). We tested if such changes could be explained by hydration and would exceed what may be expected from normal ageing. Subjects (n=26) of a previous study were re-assessed and were randomised to 3 groups of a hydration escalation trial (no hydration, 1× hydration, 2× hydration). Automated retinal layer segmentations were performed for the macular retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL) and outer nuclear layer (ONL). The averaged volumes were calculated for the central foveola, 3 mm and 6 mm circles of the ETDRS grid. Following oral hydration there were no significant differences of retinal layer thicknesses between the three randomised groups in any of the ETDRS regions at any time-point. Ageing related changes were significant over an 18 month period for the GCL. The negative outcome of this trial implies that, until the causes for the observed variation are resolved, investigators may need to accept, and include into trial power calculations, a small degree of variation (<1%) of quantitative SD-OCT imaging either due to human physiology or instrument/software related factors.

  16. Comparing Environmental Dose Rate Meters: A Method to Determine Natural and Non-natural Variations in External Radiation Levels

    Energy Technology Data Exchange (ETDEWEB)

    Reinen, A.J.M.; Slaper, H.; Overwater, R.M.W.; Stoop, P

    2000-07-01

    A method is described to determine low excess dose rates from a radiation source in the environment, which are small compared to the natural fluctuations of the background radiation. First a 'virtual reference dose rate meter' is constructed from data of the national monitoring network, to know the natural variations of the background radiation. Results from this virtual monitor are then compared to data of dose rate meters at sites of interest, to determine non-natural or very local natural variations and excess dose rates. Daily averaged excess dose rates down to 2 to 3 nSv.h{sup -1} can be identified. The method is applied successfully near nuclear installations in the Netherlands and can be used for all types of dose rate meters and sample frequencies. Finally, the calculations to derive the 'virtual reference dose rate meter' can also be used as a quality assessment tool for environmental radiation monitoring networks. (author)

  17. Can exploiting natural genetic variation in leaf photosynthesis contribute to increasing rice productivity? A simulation analysis.

    Science.gov (United States)

    Gu, Junfei; Yin, Xinyou; Stomph, Tjeerd-Jan; Struik, Paul C

    2014-01-01

    Rice productivity can be limited by available photosynthetic assimilates from leaves. However, the lack of significant correlation between crop yield and leaf photosynthetic rate (A) is noted frequently. Engineering for improved leaf photosynthesis has been argued to yield little increase in crop productivity because of complicated constraints and feedback mechanisms when moving up from leaf to crop level. Here we examined the extent to which natural genetic variation in A can contribute to increasing rice productivity. Using the mechanistic model GECROS, we analysed the impact of genetic variation in A on crop biomass production, based on the quantitative trait loci for various photosynthetic components within a rice introgression line population. We showed that genetic variation in A of 25% can be scaled up equally to crop level, resulting in an increase in biomass of 22-29% across different locations and years. This was probably because the genetic variation in A resulted not only from Rubisco (ribulose 1,5-bisphosphate carboxylase/oxygenase)-limited photosynthesis but also from electron transport-limited photosynthesis; as a result, photosynthetic rates could be improved for both light-saturated and light-limited leaves in the canopy. Rice productivity could be significantly improved by mining the natural variation in existing germ-plasm, especially the variation in parameters determining light-limited photosynthesis.

  18. Natural variation in flowering time among populations of the annual crucifer Arabidopsis thaliana

    NARCIS (Netherlands)

    Hammad, I.; Van Tienderen, P.H.

    1997-01-01

    Genetic variation in flowering time was studied in four natural populations of Arabidopsis thaliana, using greenhouse experiments. Two populations from ruderal sites flowered early, two others from river dykes late. However, the late flowering plants flowered almost as early as the others after cold

  19. Exploring and exploiting natural variation in the wings of a predatory ladybird beetle for biological control

    NARCIS (Netherlands)

    Lommen, Suzanne Theresia Esther

    2013-01-01

    The central theme of this PhD thesis is natural variation in the wing length of the predatory two-spot ladybird beetle, Adalia bipunctata. ‘Wingless’ individuals of this species occur occasionally. They possess truncated wing covers and flight wings and cannot fly, but the extent of the reduction is

  20. Seasonal variations of all-cause and cause-specific mortality by age, gender, and socioeconomic condition in urban and rural areas of Bangladesh

    Directory of Open Access Journals (Sweden)

    Burkart Katrin

    2011-08-01

    Full Text Available Abstract Background Mortality exhibits seasonal variations, which to a certain extent can be considered as mid-to long-term influences of meteorological conditions. In addition to atmospheric effects, the seasonal pattern of mortality is shaped by non-atmospheric determinants such as environmental conditions or socioeconomic status. Understanding the influence of season and other factors is essential when seeking to implement effective public health measures. The pressures of climate change make an understanding of the interdependencies between season, climate and health especially important. Methods This study investigated daily death counts collected within the Sample Vital Registration System (VSRS established by the Bangladesh Bureau of Statistics (BBS. The sample was stratified by location (urban vs. rural, gender and socioeconomic status. Furthermore, seasonality was analyzed for all-cause mortality, and several cause-specific mortalities. Daily deviation from average mortality was calculated and seasonal fluctuations were elaborated using non parametric spline smoothing. A seasonality index for each year of life was calculated in order to assess the age-dependency of seasonal effects. Results We found distinctive seasonal variations of mortality with generally higher levels during the cold season. To some extent, a rudimentary secondary summer maximum could be observed. The degree and shape of seasonality changed with the cause of death as well as with location, gender, and SES and was strongly age-dependent. Urban areas were seen to be facing an increased summer mortality peak, particularly in terms of cardiovascular mortality. Generally, children and the elderly faced stronger seasonal effects than youths and young adults. Conclusion This study clearly demonstrated the complex and dynamic nature of seasonal impacts on mortality. The modifying effect of spatial and population characteristics were highlighted. While tropical regions have

  1. Genomic analysis of QTLs and genes altering natural variation in stochastic noise.

    Science.gov (United States)

    Jimenez-Gomez, Jose M; Corwin, Jason A; Joseph, Bindu; Maloof, Julin N; Kliebenstein, Daniel J

    2011-09-01

    Quantitative genetic analysis has long been used to study how natural variation of genotype can influence an organism's phenotype. While most studies have focused on genetic determinants of phenotypic average, it is rapidly becoming understood that stochastic noise is genetically determined. However, it is not known how many traits display genetic control of stochastic noise nor how broadly these stochastic loci are distributed within the genome. Understanding these questions is critical to our understanding of quantitative traits and how they relate to the underlying causal loci, especially since stochastic noise may be directly influenced by underlying changes in the wiring of regulatory networks. We identified QTLs controlling natural variation in stochastic noise of glucosinolates, plant defense metabolites, as well as QTLs for stochastic noise of related transcripts. These loci included stochastic noise QTLs unique for either transcript or metabolite variation. Validation of these loci showed that genetic polymorphism within the regulatory network alters stochastic noise independent of effects on corresponding average levels. We examined this phenomenon more globally, using transcriptomic datasets, and found that the Arabidopsis transcriptome exhibits significant, heritable differences in stochastic noise. Further analysis allowed us to identify QTLs that control genomic stochastic noise. Some genomic QTL were in common with those altering average transcript abundance, while others were unique to stochastic noise. Using a single isogenic population, we confirmed that natural variation at ELF3 alters stochastic noise in the circadian clock and metabolism. Since polymorphisms controlling stochastic noise in genomic phenotypes exist within wild germplasm for naturally selected phenotypes, this suggests that analysis of Arabidopsis evolution should account for genetic control of stochastic variance and average phenotypes. It remains to be determined if natural

  2. Natural variation in the strength and direction of male mating preferences for female pheromones in Drosophila melanogaster.

    Science.gov (United States)

    Pischedda, Alison; Shahandeh, Michael P; Cochrane, Wesley G; Cochrane, Veronica A; Turner, Thomas L

    2014-01-01

    Many animal species communicate using chemical signals. In Drosophila, cuticular hydrocarbons (CHCs) are involved in species and sexual identification, and have long been thought to act as stimulatory pheromones as well. However, a previous study reported that D. melanogaster males were more attracted to females that were lacking CHCs. This surprising result is consistent with several evolutionary hypotheses but is at odds with other work demonstrating that female CHCs are attractive to males. Here, we investigated natural variation in male preferences for female pheromones using transgenic flies that cannot produce CHCs. By perfuming females with CHCs and performing mate choice tests, we found that some male genotypes prefer females with pheromones, some have no apparent preference, and at least one male genotype prefers females without pheromones. This variation provides an excellent opportunity to further investigate the mechanistic causes and evolutionary implications of divergent pheromone preferences in D. melanogaster males.

  3. An interpretation of induced electric currents in long pipelines caused by natural geomagnetic sources of the upper atmosphere

    Science.gov (United States)

    Campbell, W.H.

    1986-01-01

    Electric currents in long pipelines can contribute to corrosion effects that limit the pipe's lifetime. One cause of such electric currents is the geomagnetic field variations that have sources in the Earth's upper atmosphere. Knowledge of the general behavior of the sources allows a prediction of the occurrence times, favorable locations for the pipeline effects, and long-term projections of corrosion contributions. The source spectral characteristics, the Earth's conductivity profile, and a corrosion-frequency dependence limit the period range of the natural field changes that affect the pipe. The corrosion contribution by induced currents from geomagnetic sources should be evaluated for pipelines that are located at high and at equatorial latitudes. At midlatitude locations, the times of these natural current maxima should be avoided for the necessary accurate monitoring of the pipe-to-soil potential. ?? 1986 D. Reidel Publishing Company.

  4. Natural selection affects multiple aspects of genetic variation at putatively peutral sites across the human genome

    DEFF Research Database (Denmark)

    Lohmueller, Kirk E; Albrechtsen, Anders; Li, Yingrui;

    2011-01-01

    A major question in evolutionary biology is how natural selection has shaped patterns of genetic variation across the human genome. Previous work has documented a reduction in genetic diversity in regions of the genome with low recombination rates. However, it is unclear whether other summaries...... and that human diversity, human-chimp divergence, and average minor allele frequency are reduced near genes. Population genetic simulations show that either positive natural selection acting on favorable mutations or negative natural selection acting against deleterious mutations can explain these correlations...... of genetic variation, like allele frequencies, are also correlated with recombination rate and whether these correlations can be explained solely by negative selection against deleterious mutations or whether positive selection acting on favorable alleles is also required. Here we attempt to address...

  5. Variation in the Displacement of Base Isolation System Caused by an Uncertainty of Mechanical Properties

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Junghan; Kim, Minkyu; Choi, Inkil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    In this study, the variations of the displacement response of a simplified isolation system were evaluated. The variation of a horizontal translation displacement and the eccentricity of a system stiffness caused by the uncertainty of mechanical property of isolators are quantitatively calculated. These procedures can be used to estimate the probabilistic distribution of the responses of an isolation system efficiently. A performance-based approach was introduced in the seismic design criteria of nuclear power plants such as the ASCE 43-05. In this approach, a risk-based concept considering the probability of unacceptable performance was suggested. Therefore, it is indispensable that design variables are regarded as stochastic variables and their distributions should be estimated. In the design of a base isolation system, the displacement response of an isolator induced by an earthquake event is most important design variable. The displacement response is affected by mechanical properties of an isolator as well as an input ground motion. In this study, the several contribution factors to the displacement response of an isolation system using elastomeric lead rubber bearings (LRB) were evaluated by the simplified analysis methods.

  6. Potassium Retention under Salt Stress Is Associated with Natural Variation in Salinity Tolerance among Arabidopsis Accessions.

    Directory of Open Access Journals (Sweden)

    Yanling Sun

    Full Text Available Plants are exposed to various environmental stresses during their life cycle such as salt, drought and cold. Natural variation mediated plant growth adaptation has been employed as an effective approach in response to the diverse environmental cues such as salt stress. However, the molecular mechanism underlying this process is not well understood. In the present study, a collection of 82 Arabidopsis thaliana accessions (ecotypes was screened with a view to identify variation for salinity tolerance. Seven accessions showed a higher level of tolerance than Col-0. The young seedlings of the tolerant accessions demonstrated a higher K(+ content and a lower Na(+/K(+ ratio when exposed to salinity stress, but its Na(+ content was the same as that of Col-0. The K(+ transporter genes AtHAK5, AtCHX17 and AtKUP1 were up-regulated significantly in almost all the tolerant accessions, even in the absence of salinity stress. There was little genetic variation or positive transcriptional variation between the selections and Col-0 with respect to Na+-related transporter genes, as AtSOS genes, AtNHX1 and AtHKT1;1. In addition, under salinity stress, these selections accumulated higher compatible solutes and lower reactive oxygen species than did Col-0. Taken together, our results showed that natural variation in salinity tolerance of Arabidopsis seems to have been achieved by the strong capacity of K(+ retention.

  7. Seasonal variation in dust events and the causes of the variation in the Tarim Basin,China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    We analyzed dust event occurrence and its seasonal distribution at 16 sites in the Tarim Basin,China.Although the overall frequency of dust events was the highest in spring in this region,its variation in other seasons could be classified into three patterns:(1) frequency of dust events in autumn > that in summer > that in winter(at the Kashi and Kuche sites);(2) frequency in summer > that in winter > that in autumn(at the Ruoqiang site);and(3) frequency in summer > that in autumn > that in winter(at all other areas of the Tarim Basin).The frequency of dust events and their seasonal variations in the Tarim Basin were mainly controlled by wind speed and locally available dust sources;the former was the key control when dust sources did not differ significantly.The seasonal variation in evaporation had a smaller,but still significant effect on the frequency of dust events.

  8. Strong intensity variations of laser feedback interferometer caused by atmospheric turbulence

    Institute of Scientific and Technical Information of China (English)

    Yiyi Sun(孙毅义); Zhiping Li(李治平)

    2003-01-01

    The significant variation of the laser output can be caused by feedback of a small part of laser beam, whichis reflected or backscattered by a target at a long distance from laser source, into the laser cavity. Thispaper describes and analyzes theoretically and experimentally the influence of atmospheric turbulence oninterference caused by laser feedback. The influence depends upon both the energy of feedback into thelaser cavity and the strength of turbulence over a laser propagation path in the atmosphere. In the caseof stronger energy of feedback and weak turbulence variance of fluctuation of the laser output can beenhanced by hundreds to thousands times. From our measurements and theoretical analysis it shows thatthese significant enhancements can result from the change of laser-cavity-modes which can be stimulatedsimultaneously and from beat oscillations between a variety of frequencies of laser modes. This also canresult from optical chaos inside the laser resonator because a non-separable distorted external cavity canbecome a prerequisite for optical chaos.

  9. Magnetic field variation caused by rotational speed change in a magnetohydrodynamic dynamo.

    Science.gov (United States)

    Miyagoshi, Takehiro; Hamano, Yozo

    2013-09-20

    We have performed numerical magnetohydrodynamic dynamo simulations in a spherical shell with rotational speed or length-of-day (LOD) variation, which is motivated by correlations between geomagnetic field and climatic variations with ice and non-ice ages. The results show that LOD variation leads to magnetic field variation whose amplitude is considerably larger than that of LOD variation. The heat flux at the outer sphere and the zonal flow also change. The mechanism of the magnetic field variation due to LOD variation is also found. The keys are changes of dynamo activity and Joule heating.

  10. Intraseasonal variation in survival and probable causes of mortality in greater sage-grouse Centrocercus urophasianus

    Science.gov (United States)

    Blomberg, Erik J.; Gibson, Daniel; Sedinger, James S.; Casazza, Michael L.; Coates, Peter S.

    2013-01-01

    The mortality process is a key component of avian population dynamics, and understanding factors that affect mortality is central to grouse conservation. Populations of greater sage-grouse Centrocercus urophasianus have declined across their range in western North America. We studied cause-specific mortality of radio-marked sage-grouse in Eureka County, Nevada, USA, during two seasons, nesting (2008-2012) and fall (2008-2010), when survival was known to be lower compared to other times of the year. We used known-fate and cumulative incidence function models to estimate weekly survival rates and cumulative risk of cause-specific mortalities, respectively. These methods allowed us to account for temporal variation in sample size and staggered entry of marked individuals into the sample to obtain robust estimates of survival and cause-specific mortality. We monitored 376 individual sage-grouse during the course of our study, and investigated 87 deaths. Predation was the major source of mortality, and accounted for 90% of all mortalities during our study. During the nesting season (1 April - 31 May), the cumulative risk of predation by raptors (0.10; 95% CI: 0.05-0.16) and mammals (0.08; 95% CI: 0.03-013) was relatively equal. In the fall (15 August - 31 October), the cumulative risk of mammal predation was greater (M(mam) = 0.12; 95% CI: 0.04-0.19) than either predation by raptors (M(rap) = 0.05; 95% CI: 0.00-0.10) or hunting harvest (M(hunt) = 0.02; 95% CI: 0.0-0.06). During both seasons, we observed relatively few additional sources of mortality (e.g. collision) and observed no evidence of disease-related mortality (e.g. West Nile Virus). In general, we found little evidence for intraseasonal temporal variation in survival, suggesting that the nesting and fall seasons represent biologically meaningful time intervals with respect to sage-grouse survival.

  11. Natural selection affects multiple aspects of genetic variation at putatively peutral sites across the human genome

    DEFF Research Database (Denmark)

    Lohmueller, Kirk E; Albrechtsen, Anders; Li, Yingrui;

    2011-01-01

    throughout the genome. Further, we show that the widespread presence of weakly deleterious alleles, rather than a small number of strongly positively selected mutations, is responsible for the correlation between neutral genetic diversity and recombination rate. This work suggests that natural selection has......A major question in evolutionary biology is how natural selection has shaped patterns of genetic variation across the human genome. Previous work has documented a reduction in genetic diversity in regions of the genome with low recombination rates. However, it is unclear whether other summaries...... and that human diversity, human-chimp divergence, and average minor allele frequency are reduced near genes. Population genetic simulations show that either positive natural selection acting on favorable mutations or negative natural selection acting against deleterious mutations can explain these correlations...

  12. Effects of long-term exposure to air pollution on natural-cause mortality

    DEFF Research Database (Denmark)

    Beelen, Rob; Raaschou-Nielsen, Ole Lundsgaard; Stafoggia, Massimo

    2014-01-01

    Few studies on long-term exposure to air pollution and mortality have been reported from Europe. Within the multicentre European Study of Cohorts for Air Pollution Effects (ESCAPE), we aimed to investigate the association between natural-cause mortality and long-term exposure to several air...... pollutants....

  13. The nature and causes of unintended events reported at 10 internal medicine departments.

    NARCIS (Netherlands)

    Lubberding, S.; Zwaan, L.; Timmermans, D.R.M.; Wagner, C.

    2011-01-01

    Objective: This study aimed to examine the nature and causes of unintended events (UEs) at internal medicine departments (IMD). Methods: An observational study was conducted at 10 IMDs in 8 Dutch hospitals. The study period per participating department was 5 to 14 weeks. During this period, staff we

  14. Discriminating Natural Variation from Legacies of Disturbance in Semi-Arid Forests, Southwestern USA

    Science.gov (United States)

    Swetnam, T. L.; Lynch, A. M.; Falk, D. A.; Yool, S. R.; Guertin, D. P.

    2014-12-01

    Characterizing differences in existing vegetation driven by natural variation versus disturbance legacies could become a critical component of applied forest management practice with important implications for monitoring ecologic succession and eco-hydrological interactions within the critical zone. Here we characterize variations in aerial LiDAR derived forest structure at individual tree scale in Arizona and New Mexico. Differences in structure result from both topographic and climatological variations and from natural and human related disturbances. We chose a priori undisturbed and disturbed sites that included preservation, development, logging and wildfire as exemplars. We compare two topographic indices, the topographic position index (TPI) and topographic wetness index (TWI), to two local indicators of spatial association (LISA): the Getis-Ord Gi and Anselin's Moran I. We found TPI and TWI correlate well to positive z-scores (tall trees in tall neighborhoods) in undisturbed areas and that disturbed areas are clearly defined by negative z-scores, in some cases better than what is visible from traditional orthophotography and existing GIS maps. These LISA methods also serve as a robust technique for creating like-clustered stands, i.e. common stands used in forest inventory monitoring. This research provides a significant advancement in the ability to (1) quantity variation in forest structure across topographically complex landscapes, (2) identify and map previously unrecorded disturbance locations, and (3) quantify the different impacts of disturbance within the perimeter of a stand or event at ecologically relevant scale.

  15. Natural variation in Arabidopsis thaliana as a tool for highlighting differential drought responses.

    Directory of Open Access Journals (Sweden)

    Oumaya Bouchabke

    Full Text Available To test whether natural variation in Arabidopsis could be used to dissect out the genetic basis of responses to drought stress, we characterised a number of accessions. Most of the accessions belong to a core collection that was shown to maximise the genetic diversity captured for a given number of individual accessions in Arabidopsis thaliana. We measured total leaf area (TLA, Electrolyte Leakage (EL, Relative Water Content (RWC, and Cut Rosette Water Loss (CRWL in control and mild water deficit conditions. A Principal Component Analysis revealed which traits explain most of the variation and showed that some accessions behave differently compared to the others in drought conditions, these included Ita-0, Cvi-0 and Shahdara. This study relied on genetic variation found naturally within the species, in which populations are assumed to be adapted to their environment. Overall, Arabidopsis thaliana showed interesting phenotypic variations in response to mild water deficit that can be exploited to identify genes and alleles important for this complex trait.

  16. Natural variation in Arabidopsis thaliana as a tool for highlighting differential drought responses.

    Science.gov (United States)

    Bouchabke, Oumaya; Chang, Fengqi; Simon, Matthieu; Voisin, Roger; Pelletier, Georges; Durand-Tardif, Mylène

    2008-02-27

    To test whether natural variation in Arabidopsis could be used to dissect out the genetic basis of responses to drought stress, we characterised a number of accessions. Most of the accessions belong to a core collection that was shown to maximise the genetic diversity captured for a given number of individual accessions in Arabidopsis thaliana. We measured total leaf area (TLA), Electrolyte Leakage (EL), Relative Water Content (RWC), and Cut Rosette Water Loss (CRWL) in control and mild water deficit conditions. A Principal Component Analysis revealed which traits explain most of the variation and showed that some accessions behave differently compared to the others in drought conditions, these included Ita-0, Cvi-0 and Shahdara. This study relied on genetic variation found naturally within the species, in which populations are assumed to be adapted to their environment. Overall, Arabidopsis thaliana showed interesting phenotypic variations in response to mild water deficit that can be exploited to identify genes and alleles important for this complex trait.

  17. A genome-wide, fine-scale map of natural pigmentation variation in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Héloïse Bastide

    2013-06-01

    Full Text Available Various approaches can be applied to uncover the genetic basis of natural phenotypic variation, each with their specific strengths and limitations. Here, we use a replicated genome-wide association approach (Pool-GWAS to fine-scale map genomic regions contributing to natural variation in female abdominal pigmentation in Drosophila melanogaster, a trait that is highly variable in natural populations and highly heritable in the laboratory. We examined abdominal pigmentation phenotypes in approximately 8000 female European D. melanogaster, isolating 1000 individuals with extreme phenotypes. We then used whole-genome Illumina sequencing to identify single nucleotide polymorphisms (SNPs segregating in our sample, and tested these for associations with pigmentation by contrasting allele frequencies between replicate pools of light and dark individuals. We identify two small regions near the pigmentation genes tan and bric-à-brac 1, both corresponding to known cis-regulatory regions, which contain SNPs showing significant associations with pigmentation variation. While the Pool-GWAS approach suffers some limitations, its cost advantage facilitates replication and it can be applied to any non-model system with an available reference genome.

  18. Patient health causes substantial portion of geographic variation in Medicare costs.

    Science.gov (United States)

    Collado, Megan

    2013-10-01

    Key findings. (1) Substantial geographic variation exists in Medicare costs, but to determine the source and extent of this variation requires proper accounting for population health differences. (2) While physician practice patterns likely affect Medicare geographic cost variations, population health explains at least 75 to 85 percent of the variations—more than previously estimated. (3) Policy strategies should consider the magnitude of the impact of beneficiary health status on Medicare costs in order to address geographic variation.

  19. Variation in natural selection for growth and phlorotannins in the brown alga Fucus vesiculosus.

    Science.gov (United States)

    Jormalainen, V; Honkanen, T

    2004-07-01

    Directional selection for plant traits associated with resistance to herbivory tends to eliminate genetic variation in such traits. On the other hand, balancing selection arising from trade-offs between resistance and growth or spatially variable selection acts against the elimination of genetic variation. We explore both the amount of genetic variation and variability of natural selection for growth and concentration of phenolic secondary compounds, phlorotannins, in the brown alga Fucus vesiculosus. We measured variation in selection at two growing depths and two levels of nutrient availability in algae that had faced two kinds of past growing environments. Genetic variation was low for growth but high for phlorotannins. The form and strength of selection for both focal traits depended on the past growing environment of the algae. We found strong directional selection for growth rate in algae previously subjected to higher ultraviolet radiation, but not in algae previously subjected to higher nutrient availability. Stabilizing selection for growth occurred especially in the deep growing environment. Selection for phlorotannins was generally weak, but in some past-environment-current-environment combinations we detected either directional selection against phlorotannins or stabilizing selection. Thus, phlorotannins are not selectively neutral but affect the fitness of F. vesiculosus. In particular, there may be a fitness cost of producing phlorotannins, but the realization of such a cost varies from one environment to another. Genetic correlations between selective environments were high for growth but nonexistent for phlorotannins, emphasizing the high phenotypic plasticity of phlorotannin production. The highly heterogeneous selection, including directional, stabilizing, and spatially variable selection as well as temporal change in selection due to responses to past environmental conditions, probably maintains a high amount of genetic variation in phlorotannins

  20. Variation in infectivity and aggressiveness in space and time in wild host-pathogen systems: causes and consequences.

    Science.gov (United States)

    Tack, A J M; Thrall, P H; Barrett, L G; Burdon, J J; Laine, A-L

    2012-10-01

    Variation in host resistance and in the ability of pathogens to infect and grow (i.e. pathogenicity) is important as it provides the raw material for antagonistic (co)evolution and therefore underlies risks of disease spread, disease evolution and host shifts. Moreover, the distribution of this variation in space and time may inform us about the mode of coevolutionary selection (arms race vs. fluctuating selection dynamics) and the relative roles of G × G interactions, gene flow, selection and genetic drift in shaping coevolutionary processes. Although variation in host resistance has recently been reviewed, little is known about overall patterns in the frequency and scale of variation in pathogenicity, particularly in natural systems. Using 48 studies from 30 distinct host-pathogen systems, this review demonstrates that variation in pathogenicity is ubiquitous across multiple spatial and temporal scales. Quantitative analysis of a subset of extensively studied plant-pathogen systems shows that the magnitude of within-population variation in pathogenicity is large relative to among-population variation and that the distribution of pathogenicity partly mirrors the distribution of host resistance. At least part of the variation in pathogenicity found at a given spatial scale is adaptive, as evidenced by studies that have examined local adaptation at scales ranging from single hosts through metapopulations to entire continents and - to a lesser extent - by comparisons of pathogenicity with neutral genetic variation. Together, these results support coevolutionary selection through fluctuating selection dynamics. We end by outlining several promising directions for future research.

  1. Cyclic Combustion Variations in Dual Fuel Partially Premixed Pilot-Ignited Natural Gas Engines

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, K. K. [Mississippi State Univ., MS (United States). Dept. of Mechanical Engineering; Krishnan, S. R. [Mississippi State Univ., MS (United States). Dept. of Mechanical Engineering; Qi, Y. [Caterpillar, Inc., Peoria, IL (United States)

    2012-05-09

    Dual fuel pilot ignited natural gas engines are identified as an efficient and viable alternative to conventional diesel engines. This paper examines cyclic combustion fluctuations in conventional dual fuel and in dual fuel partially premixed low temperature combustion (LTC). Conventional dual fueling with 95% (energy basis) natural gas (NG) substitution reduces NOx emissions by almost 90%t relative to straight diesel operation; however, this is accompanied by 98% increase in HC emissions, 10 percentage points reduction in fuel conversion efficiency (FCE) and 12 percentage points increase in COVimep. Dual fuel LTC is achieved by injection of a small amount of diesel fuel (2-3 percent on an energy basis) to ignite a premixed natural gas₋air mixture to attain very low NOx emissions (less than 0.2 g/kWh). Cyclic variations in both combustion modes were analyzed by observing the cyclic fluctuations in start of combustion (SOC), peak cylinder pressures (Pmax), combustion phasing (Ca50), and the separation between the diesel injection event and Ca50 (termed "relative combustion phasing" ). For conventional dual fueling, as % NG increases, Pmax decreases, SOC and Ca50 are delayed, and cyclic variations increase. For dual fuel LTC, as diesel injection timing is advanced from 20° to 60° BTDC, the relative combustion phasing is identified as an important combustion parameter along with SoC, Pmax, and CaPmax. For both combustion modes, cyclic variations were characterized by alternating slow and fast burn cycles, especially at high %NG and advanced injection timings. Finally, heat release return maps were analyzed to demonstrate thermal management strategies as an effective tool to mitigate cyclic combustion variations, especially in dual fuel LTC.

  2. Dose variations caused by setup errors in intracranial stereotactic radiotherapy: A PRESAGE study

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Kieyin [School of Medical Sciences, RMIT University, Melbourne (Australia); Gagliardi, Frank [School of Medical Sciences, RMIT University, Melbourne (Australia); William Buckland Radiotherapy Centre, Melbourne (Australia); Alqathami, Mamdooh [School of Medical Sciences, RMIT University, Melbourne (Australia); Ackerly, Trevor [William Buckland Radiotherapy Centre, Melbourne (Australia); Geso, Moshi, E-mail: moshi.geso@rmit.edu.au [School of Medical Sciences, RMIT University, Melbourne (Australia)

    2014-01-01

    Stereotactic radiotherapy (SRT) requires tight margins around the tumor, thus producing a steep dose gradient between the tumor and the surrounding healthy tissue. Any setup errors might become clinically significant. To date, no study has been performed to evaluate the dosimetric variations caused by setup errors with a 3-dimensional dosimeter, the PRESAGE. This research aimed to evaluate the potential effect that setup errors have on the dose distribution of intracranial SRT. Computed tomography (CT) simulation of a CIRS radiosurgery head phantom was performed with 1.25-mm slice thickness. An ideal treatment plan was generated using Brainlab iPlan. A PRESAGE was made for every treatment with and without errors. A prescan using the optical CT scanner was carried out. Before treatment, the phantom was imaged using Brainlab ExacTrac. Actual radiotherapy treatments with and without errors were carried out with the Novalis treatment machine. Postscan was performed with an optical CT scanner to analyze the dose irradiation. The dose variation between treatments with and without errors was determined using a 3-dimensional gamma analysis. Errors are clinically insignificant when the passing ratio of the gamma analysis is 95% and above. Errors were clinically significant when the setup errors exceeded a 0.7-mm translation and a 0.5° rotation. The results showed that a 3-mm translation shift in the superior-inferior (SI), right-left (RL), and anterior-posterior (AP) directions and 2° couch rotation produced a passing ratio of 53.1%. Translational and rotational errors of 1.5 mm and 1°, respectively, generated a passing ratio of 62.2%. Translation shift of 0.7 mm in the directions of SI, RL, and AP and a 0.5° couch rotation produced a passing ratio of 96.2%. Preventing the occurrences of setup errors in intracranial SRT treatment is extremely important as errors greater than 0.7 mm and 0.5° alter the dose distribution. The geometrical displacements affect dose delivery

  3. Natural allelic variation of the IL-21 receptor modulates ischemic stroke infarct volume.

    Science.gov (United States)

    Lee, Han Kyu; Keum, Sehoon; Sheng, Huaxin; Warner, David S; Lo, Donald C; Marchuk, Douglas A

    2016-08-01

    Risk for ischemic stroke has a strong genetic basis, but heritable factors also contribute to the extent of damage after a stroke has occurred. We previously identified a locus on distal mouse chromosome 7 that contributes over 50% of the variation in postischemic cerebral infarct volume observed between inbred strains. Here, we used ancestral haplotype analysis to fine-map this locus to 12 candidate genes. The gene encoding the IL-21 receptor (Il21r) showed a marked difference in strain-specific transcription levels and coding variants in neonatal and adult cortical tissue. Collateral vessel connections were moderately reduced in Il21r-deficient mice, and cerebral infarct volume increased 2.3-fold, suggesting that Il21r modulates both collateral vessel anatomy and innate neuroprotection. In brain slice explants, oxygen deprivation (OD) activated apoptotic pathways and increased neuronal cell death in IL-21 receptor-deficient (IL-21R-deficient) mice compared with control animals. We determined that the neuroprotective effects of IL-21R arose from signaling through JAK/STAT pathways and upregulation of caspase 3. Thus, natural genetic variation in murine Il21r influences neuronal cell viability after ischemia by modulating receptor function and downstream signal transduction. The identification of neuroprotective genes based on naturally occurring allelic variations has the potential to inform the development of drug targets for ischemic stroke treatment.

  4. Genetic architecture of natural variation of telomere length in Arabidopsis thaliana.

    Science.gov (United States)

    Fulcher, Nick; Teubenbacher, Astrid; Kerdaffrec, Envel; Farlow, Ashley; Nordborg, Magnus; Riha, Karel

    2015-02-01

    Telomeres represent the repetitive sequences that cap chromosome ends and are essential for their protection. Telomere length is known to be highly heritable and is derived from a homeostatic balance between telomeric lengthening and shortening activities. Specific loci that form the genetic framework underlying telomere length homeostasis, however, are not well understood. To investigate the extent of natural variation of telomere length in Arabidopsis thaliana, we examined 229 worldwide accessions by terminal restriction fragment analysis. The results showed a wide range of telomere lengths that are specific to individual accessions. To identify loci that are responsible for this variation, we adopted a quantitative trait loci (QTL) mapping approach with multiple recombinant inbred line (RIL) populations. A doubled haploid RIL population was first produced using centromere-mediated genome elimination between accessions with long (Pro-0) and intermediate (Col-0) telomere lengths. Composite interval mapping analysis of this population along with two established RIL populations (Ler-2/Cvi-0 and Est-1/Col-0) revealed a number of shared and unique QTL. QTL detected in the Ler-2/Cvi-0 population were examined using near isogenic lines that confirmed causative regions on chromosomes 1 and 2. In conclusion, this work describes the extent of natural variation of telomere length in A. thaliana, identifies a network of QTL that influence telomere length homeostasis, examines telomere length dynamics in plants with hybrid backgrounds, and shows the effects of two identified regions on telomere length regulation.

  5. Measurement of isotope abundance variations in nature by gravimetric spiking isotope dilution analysis (GS-IDA).

    Science.gov (United States)

    Chew, Gina; Walczyk, Thomas

    2013-04-02

    Subtle variations in the isotopic composition of elements carry unique information about physical and chemical processes in nature and are now exploited widely in diverse areas of research. Reliable measurement of natural isotope abundance variations is among the biggest challenges in inorganic mass spectrometry as they are highly sensitive to methodological bias. For decades, double spiking of the sample with a mix of two stable isotopes has been considered the reference technique for measuring such variations both by multicollector-inductively coupled plasma mass spectrometry (MC-ICPMS) and multicollector-thermal ionization mass spectrometry (MC-TIMS). However, this technique can only be applied to elements having at least four stable isotopes. Here we present a novel approach that requires measurement of three isotope signals only and which is more robust than the conventional double spiking technique. This became possible by gravimetric mixing of the sample with an isotopic spike in different proportions and by applying principles of isotope dilution for data analysis (GS-IDA). The potential and principle use of the technique is demonstrated for Mg in human urine using MC-TIMS for isotopic analysis. Mg is an element inaccessible to double spiking methods as it consists of three stable isotopes only and shows great potential for metabolically induced isotope effects waiting to be explored.

  6. Through The Looking Glass: The Causes Of Variations In "Amorphous” Silicate Spectral Features.

    Science.gov (United States)

    Speck, Angela; Hofmeister, A. M.; Whittington, A. G.

    2009-05-01

    Silicate dust plays an essential role in many astrophysical environments. The "amorphous” silicate spectral features have been observed in our solar system, young stellar objects, star formation regions, novae, and the diffuse and dense interstellar medium as well as in extragalactic environments such as quasars and AGN. This dust contributes to the physical processes inherent in star formation processes, as well as to several aspects of interstellar processes such as gas heating and the formation of molecules. The discovery of this almost ubiquitous 10um silicate feature, led to many laboratory studies of potential cosmic dust analogs attempting to determine the exact nature of this dust. However, these various lab studies have produced inconsistent and often conflicting results. Studies of ostensibly the same material produce different spectra, which can be attributed to small differences in samples and techniques, but which leave astronomers at a loss as to interpretation of astrophysical data. We survey the compositional and structural factors that affect spectral features in "amorphous” silicates, illustrated with examples of new high-resolution spectra and previously published spectra of amorphous silicates nominally corresponding in composition to the mineral end-members forsterite (Mg2SiO4), enstatite (MgSiO3) and gehlenite (Ca2Al2SiO7). These examples highlight the sensitivity of such characteristics as peak shape, peak position, and the ratio of the 10µm and 18µm features, to subtle compositional / structural variations. By careful laboratory study, we can harness these effects on the spectral features of amorphous silicates to understand dust composition more precisely and provide a rich source of information on dust formation and processing.

  7. From Ends to Causes (and Back Again) by Metaphor: The Paradox of Natural Selection

    Science.gov (United States)

    Blancke, Stefaan; Schellens, Tammy; Soetaert, Ronald; Van Keer, Hilde; Braeckman, Johan

    2014-04-01

    Natural selection is one of the most famous metaphors in the history of science. Charles Darwin used the metaphor and the underlying analogy to frame his ideas about evolution and its main driving mechanism into a full-fledged theory. Because the metaphor turned out to be such a powerful epistemic tool, Darwin naturally assumed that he could also employ it as an educational tool to inform his contemporaries about his findings. Moreover, by using the metaphor Darwin was able to bring his theory in accordance with both the dominant philosophy of science in his time and the respected tradition of natural theology. However, as he introduced his theory of evolution by natural selection in On the origin of species in 1859, the metaphor also turned out to have a serious downside. Because of its intentional overtones, his contemporaries systematically misunderstood his metaphor not as a natural mechanism causing evolution to occur but as an agent who works towards particular ends. The difference in success between natural selection as an epistemic tool and its failure as an educational tool is labelled as a paradox. We explain the paradox from a cognitive perspective and discuss the implications for teaching evolution.

  8. Egg discrimination along a gradient of natural variation in eggshell coloration

    Science.gov (United States)

    Grim, Tomáš; Igic, Branislav; Samaš, Peter; López, Analía V.; Shawkey, Matthew D.; Hauber, Mark E.

    2017-01-01

    Accurate recognition of salient cues is critical for adaptive responses, but the underlying sensory and cognitive processes are often poorly understood. For example, hosts of avian brood parasites have long been assumed to reject foreign eggs from their nests based on the total degree of dissimilarity in colour to their own eggs, regardless of the foreign eggs' colours. We tested hosts' responses to gradients of natural (blue-green to brown) and artificial (green to purple) egg colours, and demonstrate that hosts base rejection decisions on both the direction and degree of colour dissimilarity along the natural, but not artificial, gradient of egg colours. Hosts rejected brown eggs and accepted blue-green eggs along the natural egg colour gradient, irrespective of the total perceived dissimilarity from their own egg's colour. By contrast, their responses did not vary along the artificial colour gradient. Our results demonstrate that egg recognition is specifically tuned to the natural gradient of avian eggshell colour and suggest a novel decision rule. These results highlight the importance of considering sensory reception and decision rules when studying perception, and illustrate that our understanding of recognition processes benefits from examining natural variation in phenotypes. PMID:28179521

  9. Natural variation of folate content and composition in spinach (Spinacia oleracea) germplasm.

    Science.gov (United States)

    Shohag, M J I; Wei, Yan-yan; Yu, Ning; Zhang, Jie; Wang, Kai; Patring, Johan; He, Zhen-li; Yang, Xiao-e

    2011-12-14

    Breeding to increase folate levels in edible parts of plants, termed folate biofortification, is an economical approach to fight against folate deficiency in humans, especially in the developing world. Germplasm with elevated folates are a useful genetic source for both breeding and direct use. Spinach is one of the well-know vegetables that contains a relatively high amount of folate. Currently, little is known about how much folate, and their composition varies in different spinach accessions. The aim of this study was to investigate natural variation in the folate content and composition of spinach genotypes grown under controlled environmental conditions. The folate content and composition in 67 spinach accessions were collected from the United States Department of Agriculture (USDA) and Asian Vegetable Research and Development Center (AVRDC) germplasm collections according to their origin, grown under control conditions to screen for natural diversity. Folates were extracted by a monoenzyme treatment and analyzed by a validated liquid chromatography (LC) method. The total folate content ranged from 54.1 to 173.2 μg/100 g of fresh weight, with 3.2-fold variation, and was accession-dependent. Four spinach accessions (PI 499372, NSL 6095, PI 261787, and TOT7337-B) have been identified as enriched folate content over 150 μg/100 g of fresh weight. The folate forms found were H(4)-folate, 5-CH(3)-H(4)-folate, and 5-HCO-H(4)-folate, and 10-CHO-folic acid also varied among different accessions and was responsible for variation in the total folate content. The major folate vitamer was represented by 5-CH(3)-H(4)-folate, which on average accounted for up to 52% of the total folate pool. The large variation in the total folate content and composition in diverse spinach accessions demonstrates the great genetic potential of diverse genotypes to be exploited by plant breeders.

  10. An investigation of the potential causes for the seasonal and annual variations in indoor radon concentrations.

    Science.gov (United States)

    Barazza, F; Gfeller, W; Palacios, M; Murith, C

    2015-11-01

    Indoor radon concentrations exhibit strong variations on short and long timescales. Besides human influences, meteorological factors significantly affect the radon concentrations indoors as well as outdoors. In this article, long-term measurements showing strong annual variations are presented, which take a very similar course in different buildings located in largely separated regions in Switzerland. Also, seasonal variations can be very significant. In general, variations in indoor radon levels can primarily be attributed to human influences. On the other hand, specific weather conditions can have a significant impact on indoor radon levels. In order to further investigate the connection between indoor radon levels and meteorological factors, a measuring campaign has been started in two buildings located in two different regions in Switzerland exhibiting different climatic characteristics. Preliminary results of these investigations are presented, which provide evidence for correlations between indoor radon levels and in particular outdoor temperatures, contributing to seasonal and annual as well as short-term variations in indoor radon concentrations.

  11. Neutron Moderation in the Oklo Natural Reactor and the Time Variation of alpha

    CERN Document Server

    Lamoreaux, S K

    2003-01-01

    In the analysis of the Oklo (gabon) natural reactor to test for a possible time variation of the fine structure constant alpha, a Maxwell-Boltzmann low energy neutron spectrum was assumed. We present here an analysis where a more realistic spectrum is employed and show that the most recent isotopic analysis of samples implies a non-zero change in alpha, over the last two billion years since the reactor was operating, of \\Delta\\alpha/\\alpha\\geq 2.2\\times 10^{-7} (6\\sigma confidence). Issues regarding the interpretation of the shifts of the low energy neutron resonances are discussed.

  12. Neutron moderation in the Oklo natural reactor and the time variation of α

    Science.gov (United States)

    Lamoreaux, S. K.; Torgerson, J. R.

    2004-06-01

    In previous analyses of the Oklo (Gabon) natural reactor to test for a possible time variation of the fine-structure constant α, a Maxwell-Boltzmann low energy neutron spectrum was assumed. We present here an analysis where a more realistic spectrum is employed and show that the most recent isotopic analysis of samples implies a decrease in α, over the last 2×109 years since the reactor was operating, of (αpast-αnow)/α⩾4.5×10-8 (6σ confidence). Issues regarding the interpretation of the shifts of the low energy neutron absorption resonances are discussed.

  13. Fast Oxidation Processes in a Naturally Reduced Aquifer Zone Caused by Dissolved Oxygen

    Science.gov (United States)

    Davis, J. A.; Jemison, N. E.; Williams, K. H.; Hobson, C.; Bush, R. P.

    2014-12-01

    The occurrence of naturally reduced zones is quite common in alluvial aquifers in the western U.S.A. due to the burial of woody debris in flood plains. The naturally reduced zones are heterogeneously dispersed in such aquifers and are characterized by high concentrations of organic carbon and reduced phases, including iron sulfides and reduced forms of metals, including uranium(IV). The persistence of high concentrations of dissolved uranium(VI) at uranium-contaminated aquifers on the Colorado Plateau has been attributed to slow oxidation of insoluble uranium(IV) mineral phases that are found in association with these natural reducing zones, although there is little understanding of the relative importance of various potential oxidants. Three field experiments were conducted within an alluvial aquifer adjacent to the Colorado River near Rifle, CO wherein groundwater associated with naturally reduced zones was pumped into a gas-impermeable tank, mixed with a conservative tracer (Br-), bubbled with a gas phase composed of 97% O2 and 3% CO2, and then returned to the subsurface in the same well from which it was withdrawn. Within minutes of re-injection of the oxygenated groundwater, dissolved uranium(VI) concentrations increased from less than 1 μM to greater than 2.5 μM, demonstrating that oxygen can be an important oxidant for uranium in these field systems if supplied to the naturally reduced zones. Small concentrations of nitrate were also observed in the previously nitrate-free groundwater, and Fe(II) decreased to the detection limit. These results contrast with other laboratory and field results in which oxygen was introduced to systems containing high concentrations of mackinawite (FeS) rather than the more crystalline iron sulfides found in aged, naturally reduced zones. The flux of oxygen to the naturally reduced zones in the alluvial aquifers occurs mainly through interactions between groundwater and gas phases at the water table, and seasonal variations

  14. Mechanisms causing variation in sexual size dimorphism in three sympatric, congeneric lizards.

    Science.gov (United States)

    Manicom, Carryn; Alford, Ross; Schoener, Thomas W; Schwarzkopf, Lin

    2014-06-01

    Sexual differences in adult body size (sexual size dimorphism, or SSD) ultimately can be favored by selection because larger males are more likely to be successful competitors for females, because larger females bear larger clutches, or because intersexual size differences reduce resource competition. Natural selection during juvenile development can influence sexual dimorphism of adults, and selection on adults and juveniles may differ. Studies that address the relative contributions of adult body shape dimorphism and sexually dimorphic patterns of growth and maturity are particularly useful in understanding the evolution of size dimorphism, yet they are rare. We investigated three sympatric, congeneric lizard species with different degrees and directions of adult sexual dimorphism and compared their growth patterns, survival probabilities, and intersexual trophic niche differences. Different mechanisms, even within these closely related, sympatric species, acted on juvenile lizards to produce species differences in adult SSD. Both degree and direction of dimorphism resulted from differences between the sexes in either the duration of growth or the rate of growth, but not from differences in rates of survival or selection on juvenile growth rate. Species- and sex-specific trade-offs in the allocation of energy to growth and reproduction, as well as differential timing of maturation, thus caused the growth patterns of the sexes to diverge, producing SSD. The differences that we observed in the direction of SSD among these species is consistent with their different social systems, suggesting that differential selection on adult body size has been responsible for the observed species-specific differences in juvenile growth rates and maturational timing.

  15. Sq and EEJ—A Review on the Daily Variation of the Geomagnetic Field Caused by Ionospheric Dynamo Currents

    Science.gov (United States)

    Yamazaki, Y.; Maute, A.

    2017-03-01

    A record of the geomagnetic field on the ground sometimes shows smooth daily variations on the order of a few tens of nano teslas. These daily variations, commonly known as Sq, are caused by electric currents of several μ A/m2 flowing on the sunlit side of the E-region ionosphere at about 90-150 km heights. We review advances in our understanding of the geomagnetic daily variation and its source ionospheric currents during the past 75 years. Observations and existing theories are first outlined as background knowledge for the non-specialist. Data analysis methods, such as spherical harmonic analysis, are then described in detail. Various aspects of the geomagnetic daily variation are discussed and interpreted using these results. Finally, remaining issues are highlighted to provide possible directions for future work.

  16. Sq and EEJ—A Review on the Daily Variation of the Geomagnetic Field Caused by Ionospheric Dynamo Currents

    Science.gov (United States)

    Yamazaki, Y.; Maute, A.

    2016-09-01

    A record of the geomagnetic field on the ground sometimes shows smooth daily variations on the order of a few tens of nano teslas. These daily variations, commonly known as Sq, are caused by electric currents of several μA/m2 flowing on the sunlit side of the E-region ionosphere at about 90-150 km heights. We review advances in our understanding of the geomagnetic daily variation and its source ionospheric currents during the past 75 years. Observations and existing theories are first outlined as background knowledge for the non-specialist. Data analysis methods, such as spherical harmonic analysis, are then described in detail. Various aspects of the geomagnetic daily variation are discussed and interpreted using these results. Finally, remaining issues are highlighted to provide possible directions for future work.

  17. The nature and causes of unintended events reported at ten emergency departments

    Directory of Open Access Journals (Sweden)

    van der Wal Gerrit

    2009-09-01

    Full Text Available Abstract Background Several studies on patient safety have shown that a substantial number of patients suffer from unintended harm caused by healthcare management in hospitals. Emergency departments (EDs are challenging hospital settings with regard to patient safety. There is an increased sense of urgency to take effective countermeasures in order to improve patient safety. This can only be achieved if interventions tackle the dominant underlying causes. The objectives of our study are to examine the nature and causes of unintended events in EDs and the relationship between type of event and causal factor structure. Methods Study at EDs of 10 hospitals in the Netherlands. The study period per ED was 8 to 14 weeks, in which staff were asked to report unintended events. Unintended events were broadly defined as all events, no matter how seemingly trivial or commonplace, that were unintended and could have harmed or did harm a patient. Reports were analysed with a Root Cause Analysis tool (PRISMA by an experienced researcher. Results 522 unintended events were reported. Of the events 25% was related to cooperation with other departments and 20% to problems with materials/equipment. More than half of the events had consequences for the patient, most often resulting in inconvenience or suboptimal care. Most root causes were human (60%, followed by organisational (25% and technical causes (11%. Nearly half of the root causes was external, i.e. attributable to other departments in or outside the hospital. Conclusion Event reporting gives insight into diverse unintended events. The information on unintended events may help target research and interventions to increase patient safety. It seems worthwhile to direct interventions on the collaboration between the ED and other hospital departments.

  18. A study on the nature and magnitude of variations in different traits in sugarcane

    Directory of Open Access Journals (Sweden)

    V.K. Tyagi, Satish Sharma and S.B. Bhardwaj

    2011-09-01

    Full Text Available Nature and magnitude of the variation for different agronomic traits in sugarcane under subtropical conditions of North-western Uttar Pradesh was studied. An estimation of heritability and genetic advance of these components under different environmental conditions was worked out. Fourteen sugarcane genotypes in three crop year experiment were analysed for 15 different characters and variance at phenotypic and genotypic levels, broad sense heritability, genetic advance and pooled analysis of variance were worked out. Coefficients of variation were high for the number of canes per plot, cane yield, cane weight, commercial cane sugar at 8 month stage and for sugar yield at harvesting. The highest heritability values were obtained for juice brix %, juice sucrose % and CCS % at 12 month stage, juice brix %, juice sucrose % at 8 month, cane weight, cane yield and sugar yield per plot. The lowest heritability values were observed for number of internodes, CCS % at 8 month stage, cane diameter and juice extraction % at 12 month stage. Genetic Advance was high for cane weight, cane height, number of canes per plot and cane yield. High magnitude of coefficient of variations, high heritability and maximum genetic gain for number of millable canes, cane weight and cane height showed emphatic role of these characters in clonal selection for improvement in cane and sugar yield. Variance analysis indicated significant genetic differences among the varieties for all characters.

  19. The genetic basis of natural variation in oenological traits in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Francisco Salinas

    Full Text Available Saccharomyces cerevisiae is the main microorganism responsible for wine alcoholic fermentation. The oenological phenotypes resulting from fermentation, such as the production of acetic acid, glycerol, and residual sugar concentration are regulated by multiple genes and vary quantitatively between different strain backgrounds. With the aim of identifying the quantitative trait loci (QTLs that regulate oenological phenotypes, we performed linkage analysis using three crosses between highly diverged S. cerevisiae strains. Segregants from each cross were used as starter cultures for 20-day fermentations, in synthetic wine must, to simulate actual winemaking conditions. Linkage analysis on phenotypes of primary industrial importance resulted in the mapping of 18 QTLs. We tested 18 candidate genes, by reciprocal hemizygosity, for their contribution to the observed phenotypic variation, and validated five genes and the chromosome II right subtelomeric region. We observed that genes involved in mitochondrial metabolism, sugar transport, nitrogen metabolism, and the uncharacterized ORF YJR030W explained most of the phenotypic variation in oenological traits. Furthermore, we experimentally validated an exceptionally strong epistatic interaction resulting in high level of succinic acid between the Sake FLX1 allele and the Wine/European MDH2 allele. Overall, our work demonstrates the complex genetic basis underlying wine traits, including natural allelic variation, antagonistic linked QTLs and complex epistatic interactions between alleles from strains with different evolutionary histories.

  20. Proximate causes of adaptive growth rates: growth efficiency variation among latitudinal populations of Rana temporaria.

    Science.gov (United States)

    Lindgren, B; Laurila, A

    2005-07-01

    In ectothermic organisms, declining season length and lower temperature towards higher latitudes often select for latitudinal variation in growth and development. However, the energetic mechanisms underlying this adaptive variation are largely unknown. We investigated growth, food intake and growth efficiency of Rana temporaria tadpoles from eight populations along a 1500 km latitudinal gradient across Sweden. To gain an insight into the mechanisms of adaptation at organ level, we also examined variation in tadpole gut length. The tadpoles were raised at two temperatures (16 and 20 degrees C) in a laboratory common garden experiment. We found increased growth rate towards higher latitudes, regardless of temperature treatment. This increase in growth was not because of a higher food intake rate, but populations from higher latitudes had higher growth efficiency, i.e. they were more efficient at converting ingested food into body mass. Low temperature reduced growth efficiency most strongly in southern populations. Relative gut length increased with latitude, and tadpoles at low temperature tended to have longer guts. However, variation in gut length was not the sole adaptive explanation for increased growth efficiency as latitude and body length still explained significant amounts of variation in growth efficiency. Hence, additional energetic adaptations are probably involved in growth efficiency variation along the latitudinal gradient.

  1. Natural variation of male ornamental traits of the guppy, Poecilia reticulata.

    Science.gov (United States)

    Tripathi, Namita; Hoffmann, Margarete; Dreyer, Christine

    2008-12-01

    Male ornamental traits of the guppy, Poecilia reticulata, provide an outstanding example of natural variation in sex-linked male-advantageous traits that are shaped by both sexual and environmental selection. A substantial fraction of the underlying genes is known to be genetically linked to the sex-determining region on the differentiating Y-chromosome. Intercrosses between parental populations originating from geographically distant locations in East Trinidad and Cumaná (Venezuela) were used to study segregation of ornamental traits in male progeny. In addition, we performed backcrosses to compare segregation of ornaments in presence or absence of prominent traits linked to the Y-chromosome. Another backcross strategy involving XY females from the laboratory strain zebrinus maculatus allowed studying additive and dominant effects of alleles on two different Y-chromosomes on pattern formation. For genetic mapping, we have previously developed nuclear SNP markers linked to expressed genes, including several genes known to be important for pattern formation in other species. Of these candidate genes 15 were placed on 11 different linkage groups. Our phenotypic and genotypic analysis of progeny from mapping crosses and backcrosses suggests several genetic mechanisms that enhance natural variation, namely, additive effects of codominant alleles, suppressive actions of dominant alleles, and a complex interplay between sex-linked and autosomal cofactors.

  2. Extensive natural variation for cellular hydrogen peroxide release is genetically controlled.

    Directory of Open Access Journals (Sweden)

    Homa Attar

    Full Text Available Natural variation in DNA sequence contributes to individual differences in quantitative traits. While multiple studies have shown genetic control over gene expression variation, few additional cellular traits have been investigated. Here, we investigated the natural variation of NADPH oxidase-dependent hydrogen peroxide (H(2O(2 release, which is the joint effect of reactive oxygen species (ROS production, superoxide metabolism and degradation, and is related to a number of human disorders. We assessed the normal variation of H(2O(2 release in lymphoblastoid cell lines (LCL in a family-based 3-generation cohort (CEPH-HapMap, and in 3 population-based cohorts (KORA, GenCord, HapMap. Substantial individual variation was observed, 45% of which were associated with heritability in the CEPH-HapMap cohort. We identified 2 genome-wide significant loci of Hsa12 and Hsa15 in genome-wide linkage analysis. Next, we performed genome-wide association study (GWAS for the combined KORA-GenCord cohorts (n = 279 using enhanced marker resolution by imputation (>1.4 million SNPs. We found 5 significant associations (p<5.00×10-8 and 54 suggestive associations (p<1.00×10-5, one of which confirmed the linked region on Hsa15. To replicate our findings, we performed GWAS using 58 HapMap individuals and ∼2.1 million SNPs. We identified 40 genome-wide significant and 302 suggestive SNPs, and confirmed genome signals on Hsa1, Hsa12, and Hsa15. Genetic loci within 900 kb from the known candidate gene p67phox on Hsa1 were identified in GWAS in both cohorts. We did not find replication of SNPs across all cohorts, but replication within the same genomic region. Finally, a highly significant decrease in H(2O(2 release was observed in Down Syndrome (DS individuals (p<2.88×10-12. Taken together, our results show strong evidence of genetic control of H(2O(2 in LCL of healthy and DS cohorts and suggest that cellular phenotypes, which themselves are also complex, may be

  3. Natural variation in expression of genes associated with carotenoid biosynthesis and accumulation in cassava (Manihot esculenta Crantz) storage root

    Science.gov (United States)

    Several groups have reported on massive accumulation of total carotenoids in cassava storage root (CSR). Naturally occurring color variation associated with carotenoid accumulation was observed in cassava (Manihot esculenta Crantz) storage root of landraces from Amazon. Here carotenoid profiles from...

  4. Natural variation in steroid hormone profiles of male Timber Rattlesnakes, Crotalus horridus, in northwest Arkansas.

    Science.gov (United States)

    Lind, Craig M; Beaupre, Steven J

    2014-09-15

    We describe the seasonal profile of circulating steroid hormones (testosterone and corticosterone) in relation to the breeding season in free ranging male Timber Rattlesnakes, Crotalus horridus, over the course of three active seasons. In addition, we examine variation in steroid concentrations across years and in relation to body condition. We found that seasonal profiles of plasma testosterone were different compared to other crotalines with similar mating patterns. Concentrations of testosterone were elevated above baseline in the three months leading up to the single late summer breeding season. Testosterone peaked in July at the onset of the breeding season and dropped to baseline during the peak months of breeding (August and September). Testosterone concentrations also varied annually. Although the exact cause of annual variation could not be established, our results indicate that weather patterns may have driven observed differences. Testosterone concentrations were positively related to body condition, indicating that testosterone production is modulated according to energetic status (particularly in the two months prior to the breeding season). Corticosterone did not vary seasonally or with any measured variable, a result similar to other studied crotalines. Our results highlight the importance of long-term descriptive studies of the regulatory mechanisms that underlie behavior and physiology in diverse taxa, as these mechanisms can vary greatly within and among populations and are valuable in elucidating the intrinsic and extrinsic sources of such variation.

  5. Evolutionary causes and consequences of diversified CRISPR immune profiles in natural populations.

    Science.gov (United States)

    England, Whitney E; Whitaker, Rachel J

    2013-12-01

    Host-pathogen co-evolution is a significant force which shapes the ecology and evolution of all types of organisms, and such interactions are driven by resistance and immunity mechanisms of the host. Diversity of resistance and immunity can affect the co-evolutionary trajectory of both host and pathogen. The microbial CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) system is one host immunity mechanism which offers a tractable model for examining the dynamics of diversity in an immune system. In the present article, we review CRISPR variation observed in a variety of natural populations, examine the forces which can push CRISPRs towards high or low diversity, and investigate the consequences of various levels of diversity on microbial populations.

  6. Seasonal Imbalances in Natural Gas Imports in Major Northeast Asian Countries: Variations, Reasons, Outlooks and Countermeasures

    Directory of Open Access Journals (Sweden)

    Zhaoyang Kong

    2015-02-01

    Full Text Available The seasonal imbalances and price premiums of natural gas imports (NGIs seriously affect the sustainability of these imports in major Northeast Asian countries, namely, China, Japan, and South Korea. Research on NGI seasonality might provide new insights that may help solve these issues. Unfortunately, little research has been conducted on this topic. Therefore, this paper examined the seasonalities of Chinese, Japanese, and South Korean NGIs using the X-12-ARIMA model to analyze monthly and quarterly data. The results suggest that Chinese NGIs lacks identifiable monthly or quarterly seasonality, while South Korea and Japan exhibit clearly identifiable seasonality. In Japan, NGIs exceed their average levels in January, February, July, August, September, and December; that is, Japan imports more natural gas during the winter and summer. In South Korea, NGIs exceed their average levels in January, February, March and December. In other words, South Korea typically imports more natural gas during the winter. The seasonal differences in NGIs among these countries might be explained by differences in natural gas consumption characteristics, domestic natural gas production capacity, NGI capacity, price sensitivity, and means of transportation. Based on seasonal differences and their probable causes, some suggestions are provided to promote the sustainable development of NGI.

  7. Multiple natural enemies cause distance-dependent mortality at the seed-to-seedling transition.

    Science.gov (United States)

    Fricke, Evan C; Tewksbury, Joshua J; Rogers, Haldre S

    2014-05-01

    Specialised natural enemies maintain forest diversity by reducing tree survival in a density- or distance-dependent manner. Fungal pathogens, insects and mammals are the enemy types most commonly hypothesised to cause this phenomenon. Still, their relative importance remains largely unknown, as robust manipulative experiments have generally targeted a single enemy type and life history stage. Here, we use fungicide, insecticide and physical exclosure treatments to isolate the impacts of each enemy type on two life history stages (germination and early seedling survival) in three tropical tree species. Distance dependence was evident for five of six species-stage combinations, with each enemy type causing distance dependence for at least one species stage and their importance varying widely between species and stages. Rather than implicating one enemy type as the primary agent of this phenomenon, our field experiments suggest that multiple agents acting at different life stages collectively contribute to this diversity-promoting mechanism.

  8. Natural variation in DNA methylation in ribosomal RNA genes of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Richards Eric J

    2008-09-01

    Full Text Available Abstract Background DNA methylation is an important biochemical mark that silences repetitive sequences, such as transposons, and reinforces epigenetic gene expression states. An important class of repetitive genes under epigenetic control in eukaryotic genomes encodes ribosomal RNA (rRNA transcripts. The ribosomal genes coding for the 45S rRNA precursor of the three largest eukaryotic ribosomal RNAs (18S, 5.8S, and 25–28S are found in nucleolus organizer regions (NORs, comprised of hundreds to thousands of repeats, only some of which are expressed in any given cell. An epigenetic switch, mediated by DNA methylation and histone modification, turns rRNA genes on and off. However, little is known about the mechanisms that specify and maintain the patterns of NOR DNA methylation. Results Here, we explored the extent of naturally-occurring variation in NOR DNA methylation among accessions of the flowering plant Arabidopsis thaliana. DNA methylation in coding regions of rRNA genes was positively correlated with copy number of 45S rRNA gene and DNA methylation in the intergenic spacer regions. We investigated the inheritance of NOR DNA methylation patterns in natural accessions with hypomethylated NORs in inter-strain crosses and defined three different categories of inheritance in F1 hybrids. In addition, subsequent analysis of F2 segregation for NOR DNA methylation patterns uncovered different patterns of inheritance. We also revealed that NOR DNA methylation in the Arabidopsis accession Bor-4 is influenced by the vim1-1 (variant in methylation 1-1 mutation, but the primary effect is specified by the NORs themselves. Conclusion Our results indicate that the NORs themselves are the most significant determinants of natural variation in NOR DNA methylation. However, the inheritance of NOR DNA methylation suggests the operation of a diverse set of mechanisms, including inheritance of parental methylation patterns, reconfiguration of parental NOR DNA

  9. Transcriptome-wide mining of the differentially expressed transcripts for natural variation of floral organ size in Physalis philadelphica.

    Science.gov (United States)

    Wang, Li; Li, Zhichao; He, Chaoying

    2012-11-01

    Natural phenotypic variation, a result of genetic variation, developed during evolution in response to environmental selections. Physalis philadelphica, known as tomatillo in the Solanaceae, is rich in floral and post-floral organ size diversity. However, its genetic variation is unknown. Here P. philadelphica was classified into three groups with large, intermediate, and small reproductive organ size, and a positive correlation was observed between floral organ and berry sizes. Through cDNA-amplified fragment length polymorphism (AFLP) analyses, 263 differentially expressed transcript-derived fragments (TDFs) were isolated from two accessions with different floral organ sizes. The genes encode various transcription factors, protein kinases, and enzymes, and they displayed multiple expression patterns during floral development, indicating a complexity in the genetic basis of phenotypic variation. Detailed expression analyses revealed that they were differentially expressed during floral and post-floral development, implying that they have roles in the development of flowers and fruits. Expression of three genes was further monitored in 26 accessions, and in particular the expression variation of Pp30, encoding an AP2-like transcription factor, correlates well with the observed phenotypic variations, which strongly supports an essential role for the gene in the natural variation of floral and post-floral organ size in Physalis. The results suggest that alteration in the expression pattern of a few key regulatory genes in the developmental process may be an important source of genetic variations that lead to natural variation in morphological traits.

  10. What causes the variations of the peak intensity of CIR accelerated energetic ion fluxes?

    Directory of Open Access Journals (Sweden)

    E. Keppler

    Full Text Available The variation of the peak intensity of energetic ions accelerated at CIR related shocks in the interplanetary medium as observed by instruments on board of ULYSSES during its pass towards the south polar region and from the north polar region back to its aphelium is discussed. From ULYSSES measurements alone it cannot be decided whether the observed variation is a function of latitude or of radial distance, as its orbit changes distance and latitude at the same time. Therefore ULYSSES data is compared with earlier observations by the PIONEER and VOYAGER spacecraft and concluded that the major part of the observed variation of the peak intensity seems to be due to a radial distance change, on to which, however, at higher latitudes a latitude dependent feature is superimposed.

    Key words. Interplanetary physics (Energetic particles; interplanetary shocks; general

  11. Natural variation and dosage of the HEI10 meiotic E3 ligase control Arabidopsis crossover recombination

    Science.gov (United States)

    Ziolkowski, Piotr A.; Underwood, Charles J.; Lambing, Christophe; Martinez-Garcia, Marina; Lawrence, Emma J.; Ziolkowska, Liliana; Griffin, Catherine; Choi, Kyuha; Franklin, F. Chris H.; Martienssen, Robert A.; Henderson, Ian R.

    2017-01-01

    During meiosis, homologous chromosomes undergo crossover recombination, which creates genetic diversity and balances homolog segregation. Despite these critical functions, crossover frequency varies extensively within and between species. Although natural crossover recombination modifier loci have been detected in plants, causal genes have remained elusive. Using natural Arabidopsis thaliana accessions, we identified two major recombination quantitative trait loci (rQTLs) that explain 56.9% of crossover variation in Col×Ler F2 populations. We mapped rQTL1 to semidominant polymorphisms in HEI10, which encodes a conserved ubiquitin E3 ligase that regulates crossovers. Null hei10 mutants are haploinsufficient, and, using genome-wide mapping and immunocytology, we show that transformation of additional HEI10 copies is sufficient to more than double euchromatic crossovers. However, heterochromatic centromeres remained recombination-suppressed. The strongest HEI10-mediated crossover increases occur in subtelomeric euchromatin, which is reminiscent of sex differences in Arabidopsis recombination. Our work reveals that HEI10 naturally limits Arabidopsis crossovers and has the potential to influence the response to selection. PMID:28223312

  12. Genetic variation of natural and cultured stocks of Paralichthys olivaceus by allozyme and RAPD

    Institute of Scientific and Technical Information of China (English)

    YOU Feng; ZHANG Peijun; WANG Keling; XIANG Jianhai

    2007-01-01

    Population genetics of the left-eyed flounder, Paralichthys olivaceus, including natural and cultured stocks distributed in the coastal waters near Qingdao of eastern maritime China, was analyzed in allozyme and RAPD. The results showed that among total 29 gene loci of 15 isozymes, 9 and 7 were polymorphic in natural and cultured stocks, respectively. The status of genetic diversity in P olivaceus is low in terms of polymorphic loci in chi-square test and genetic departure index of Hardy-Weinberg equilibrium. More alleles in IDHP, CAT, GDH and Ldh-C allozymes were found in the fish, which could be used as markers in assortive breeding and distinguishing stock, population or species evolution. Total 88 and 86 RAPD bands ranging from 200 to 2 500 bp were recognized individually in average of 7.8-8.0 bands per primer. The genetic diversity in cultured stock is lower than that in natural ones showing an obviously decreasing genetic divergence. Therefore, effective countermeasures must be taken to protect genetic resources of marine cultured fishes. The 2 markers have their own pros and cons. Combining the 2 markers to investigate the genetic variation of populations is suggested. The results provide basic data of this flounder and they are useful for studying genetic improvement and genetic resources of the fish.

  13. Super-emitters in natural gas infrastructure are caused by abnormal process conditions

    Science.gov (United States)

    Zavala-Araiza, Daniel; Alvarez, Ramón A; Lyon, David R.; Allen, David T.; Marchese, Anthony J.; Zimmerle, Daniel J.; Hamburg, Steven P.

    2017-01-01

    Effectively mitigating methane emissions from the natural gas supply chain requires addressing the disproportionate influence of high-emitting sources. Here we use a Monte Carlo simulation to aggregate methane emissions from all components on natural gas production sites in the Barnett Shale production region (Texas). Our total emission estimates are two-thirds of those derived from independent site-based measurements. Although some high-emitting operations occur by design (condensate flashing and liquid unloadings), they occur more than an order of magnitude less frequently than required to explain the reported frequency at which high site-based emissions are observed. We conclude that the occurrence of abnormal process conditions (for example, malfunctions upstream of the point of emissions; equipment issues) cause additional emissions that explain the gap between component-based and site-based emissions. Such abnormal conditions can cause a substantial proportion of a site's gas production to be emitted to the atmosphere and are the defining attribute of super-emitting sites. PMID:28091528

  14. Integral diagnostic in the failure causes of external corrosion of a natural gas transport pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Mora-Mendoza, J.L.; Saucedo-Robles, L.C.; Rodriguez-Clemente, H. [PEMEX Gas y Petroquimica Basica, Subdireccion de Ductos; Marina Nacional 329, Edificio B-1, Piso 8, Col. Huasteca, D.F., CP 11311 (Mexico); Gonzalez-Nunez, M.A. [Instituto de Investigaciones Electricas, Reforma 113, Col. Palmira, Cuernavaca, Morelos, CP 62490 (Mexico); Zavala-Olivares, G.; Hernandez-Gayosso, M.J. [Instituto Mexicano del Petroleo, Direccion de Exploracion y Produccion, Eje Central Lazaro Cardenas Norte 152, Col. San Bartolo Atepehuacan, D.F., CP 07730 (Mexico)

    2011-08-15

    The objective of this study consisted in investigating the possible causes which give rise to the presence of low wall pipe thicknesses on a 16'' natural gas transport pipeline, even though during the last 12-year period cathodic protection (CP) potentials were kept in the protection range at which external corrosion should not occur. Results from in-line inspection from a 16'' natural gas transport pipeline showed 46 indications with more than 80% wall thickness lost due to external corrosion in the second segment of the pipeline. Direct inspection at the indication locations, review of the CP system performance, pipeline maintenance programs and studies, allowed to make an integral diagnostic where it was found out that the main cause of external corrosion was an inappropriate coating application since the pipeline construction, this situation has originated the increase of CP shielding effects through time. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Duality-based domain decomposition with natural coarse-space for variational inequalities

    Science.gov (United States)

    Dostál, Zdenek; Neto, Francisco A. M. Gomes; Santos, Sandra A.

    2000-12-01

    An efficient non-overlapping domain decomposition algorithm of Neumann-Neumann type for solving variational inequalities arising from the elliptic boundary value problems with inequality boundary conditions has been presented. The discretized problem is first turned by the duality theory of convex programming into a quadratic programming problem with bound and equality constraints and the latter is further modified by means of orthogonal projectors to the natural coarse space introduced recently by Farhat and Roux. The resulting problem is then solved by an augmented Lagrangian type algorithm with an outer loop for the Lagrange multipliers for the equality constraints and an inner loop for the solution of the bound constrained quadratic programming problems. The projectors are shown to guarantee an optimal rate of convergence of iterative solution of auxiliary linear problems. Reported theoretical results and numerical experiments indicate high numerical and parallel scalability of the algorithm.

  16. Optimal fishery management accounting for variation in natural mortality: the Baltic sprat and herring case

    DEFF Research Database (Denmark)

    Voss, Rudi; Neuenfeldt, Stefan; Quaas, Martin F.

    2010-01-01

    possible, we adopt an economic objective function (present value of resource rents) and determine optimal management. In the Baltic Sea, mortality rates of sprat and young herring are strongly influenced by adult cod stock dynamics via predation. Furthermore, both clupeid stocks show temperature......–recruitment function. By applying the age‐structured ecological–economic model, we derive the optimal management strategy in terms of net present value of resource rents. We compare the relative importance of both processes (i.e. temperature increase via global change and variation in predation pressure via management......Economic–ecological modelling has received increasing attention in the effort to achieve sustainable fisheries. So far, mainly single‐species models have been used, which do not account for species interaction and/or climate change. However, both of these processes alter the associated natural...

  17. Micro-geographic variation of inversions in natural populations of Drosophila pseudoobscura

    Directory of Open Access Journals (Sweden)

    Salceda Víctor M.

    2006-01-01

    Full Text Available Chromosomal polymorphism for the third chromosome in Drosophila pseudoobscura has been widely studied for genetic variation in different environments or locations far apart. However, there is less information regarding sites geographically near one another. Targeting on possible micro-geographic variation in the species, a serial study was done on 12 Mexican populations grouped in four regions, including locations in Durango (DU, the border area of Guanajuato-San Luis Potosi states (GP, Chiapas (CH and Saldilo (SA. Flies were trapped in their natural habitats using fermenting bananas as bait. They were individually cultivated in the laboratory for larvae production. In a given population sample several flies were cultivated together but only one larva per culture provided salivary tissue to observe polytene chromosomes. Gene arrangements or inversions were identified and frequencies were calculated. A total of 767 third chromosomes were studied and 11 different inversions detected. The type and relative frequencies of the arrangements varied among regions. From the 11 inversions observed, 10 were found in Durango, five in Guanajuato-San Luis Potosi and Chiapas, and eight in Saltillo. The inversion frequencies in the Durango locations varied in four cases, but only one in Chiapas, three cases in Guanajuato-San Luis Potosi, and five in Saltillo. It was also observed that there were geographical gradients for inversions within regions as follows: four arrangements in Saltillo and Durango, three in Guanajuato-San Luis Potosí and one in Chiapas. Moreover, all four regions studied showed evidences for micro-geographical variation. Nevertheless, more studies are needed to elucidate the relevance of the inversion frequencies changes in neighboring populations and also any seasonal-annual frequencies observed in the locations studied here.

  18. Natural variation in genome architecture among 205 Drosophila melanogaster Genetic Reference Panel lines.

    Science.gov (United States)

    Huang, Wen; Massouras, Andreas; Inoue, Yutaka; Peiffer, Jason; Ràmia, Miquel; Tarone, Aaron M; Turlapati, Lavanya; Zichner, Thomas; Zhu, Dianhui; Lyman, Richard F; Magwire, Michael M; Blankenburg, Kerstin; Carbone, Mary Anna; Chang, Kyle; Ellis, Lisa L; Fernandez, Sonia; Han, Yi; Highnam, Gareth; Hjelmen, Carl E; Jack, John R; Javaid, Mehwish; Jayaseelan, Joy; Kalra, Divya; Lee, Sandy; Lewis, Lora; Munidasa, Mala; Ongeri, Fiona; Patel, Shohba; Perales, Lora; Perez, Agapito; Pu, LingLing; Rollmann, Stephanie M; Ruth, Robert; Saada, Nehad; Warner, Crystal; Williams, Aneisa; Wu, Yuan-Qing; Yamamoto, Akihiko; Zhang, Yiqing; Zhu, Yiming; Anholt, Robert R H; Korbel, Jan O; Mittelman, David; Muzny, Donna M; Gibbs, Richard A; Barbadilla, Antonio; Johnston, J Spencer; Stone, Eric A; Richards, Stephen; Deplancke, Bart; Mackay, Trudy F C

    2014-07-01

    The Drosophila melanogaster Genetic Reference Panel (DGRP) is a community resource of 205 sequenced inbred lines, derived to improve our understanding of the effects of naturally occurring genetic variation on molecular and organismal phenotypes. We used an integrated genotyping strategy to identify 4,853,802 single nucleotide polymorphisms (SNPs) and 1,296,080 non-SNP variants. Our molecular population genomic analyses show higher deletion than insertion mutation rates and stronger purifying selection on deletions. Weaker selection on insertions than deletions is consistent with our observed distribution of genome size determined by flow cytometry, which is skewed toward larger genomes. Insertion/deletion and single nucleotide polymorphisms are positively correlated with each other and with local recombination, suggesting that their nonrandom distributions are due to hitchhiking and background selection. Our cytogenetic analysis identified 16 polymorphic inversions in the DGRP. Common inverted and standard karyotypes are genetically divergent and account for most of the variation in relatedness among the DGRP lines. Intriguingly, variation in genome size and many quantitative traits are significantly associated with inversions. Approximately 50% of the DGRP lines are infected with Wolbachia, and four lines have germline insertions of Wolbachia sequences, but effects of Wolbachia infection on quantitative traits are rarely significant. The DGRP complements ongoing efforts to functionally annotate the Drosophila genome. Indeed, 15% of all D. melanogaster genes segregate for potentially damaged proteins in the DGRP, and genome-wide analyses of quantitative traits identify novel candidate genes. The DGRP lines, sequence data, genotypes, quality scores, phenotypes, and analysis and visualization tools are publicly available.

  19. Genetic variation detected by RAPD markers in natural populations of babassu palm (Attalea speciosa Mart.).

    Science.gov (United States)

    Santos, M F; Damasceno-Silva, K J; Carvalhaes, M A; Lima, P S C

    2015-06-10

    The purpose of this study was to analyze the effects of management on the genetic structure of natural populations of Attalea speciosa in the State of Piauí, Brazil, using random-amplified polymorphic DNA (RAPD) markers. Three babassu populations under different management systems were selected. Polymerase chain reactions were performed for 20 RAPD primers. A total of 146 bands were generated, 141 of which were polymorphic (96.58%), with a variation of 4 and 12 loci and an average of 7 bands per primer. A dendrogram revealed a clear separation between the three populations (0.57). Data reliability and node consistency were verified by bootstrap values and the cophenetic correlation coefficient (88.15%). Coefficients of similarity between pairs of genotypes ranged from 0.26 to 0.86, with a mean of 0.57. Nei's genetic diversity index (HE) value of the population sampled in Teresina was 0.212, of Esperantina it was 0.195, and of José de Freitas it was 0.207. After the HE was decomposed, the complete diversity was found to be 0.3213. Genetic differentiation between populations was 0.362, and the estimation of gene flow between populations was low (0.879). Analysis of molecular variance revealed that 59.52% of the variation was contained within populations, and 40.48% was between populations. RAPD markers were effective for genetic diversity analysis within and between natural babassu populations, and exhibited a high level of polymorphism. Genetic diversity was the highest within populations; variability was lower in the managed populations than in the undisturbed populations.

  20. Natural variation and gene regulatory basis for the responses of asparagus beans to soil drought

    Directory of Open Access Journals (Sweden)

    Pei eXu

    2015-10-01

    Full Text Available Asparagus bean (Vigna unguiculata ssp. sesquipedalis is the Asian subspecies of cowpea, a drought-resistant legume crop native to Africa. In order to explore the genetic variation of drought responses in asparagus bean, we conducted multi-year phenotyping of drought resistance traits across the Chinese asparagus bean mini-core. The phenotypic distribution indicated that the ssp. sesquipedalis subgene pool has maintained high natural variation in drought responses despite known domestic bottleneck. Thirty-nine SNP loci were found to show an association with drought resistance via a genome-wide association study (GWAS. Whole-plant water relations were compared among four genotypes by lysimetric assay. Apparent genotypic differences in transpiration patterns and the critical soil water threshold in relation to dehydration avoidance were observed, indicating a delicate adaptive mechanism for each genotype to its own climate. Microarray gene expression analyses revealed that known drought resistance pathways such as the ABA and phosphate lipid signaling pathways are conserved between genotypes, while differential regulation of certain aquaporin genes and hormonal genes may be important for the genotypic differences. Our results suggest that divergent sensitivity to soil water content is an important mechanism configuring the genotypic specific responses to water deficit. The SNP markers identified provide useful resources for marker-assisted breeding.

  1. WormQTL--public archive and analysis web portal for natural variation data in Caenorhabditis spp.

    Science.gov (United States)

    Snoek, L Basten; Van der Velde, K Joeri; Arends, Danny; Li, Yang; Beyer, Antje; Elvin, Mark; Fisher, Jasmin; Hajnal, Alex; Hengartner, Michael O; Poulin, Gino B; Rodriguez, Miriam; Schmid, Tobias; Schrimpf, Sabine; Xue, Feng; Jansen, Ritsert C; Kammenga, Jan E; Swertz, Morris A

    2013-01-01

    Here, we present WormQTL (http://www.wormqtl.org), an easily accessible database enabling search, comparative analysis and meta-analysis of all data on variation in Caenorhabditis spp. Over the past decade, Caenorhabditis elegans has become instrumental for molecular quantitative genetics and the systems biology of natural variation. These efforts have resulted in a valuable amount of phenotypic, high-throughput molecular and genotypic data across different developmental worm stages and environments in hundreds of C. elegans strains. WormQTL provides a workbench of analysis tools for genotype-phenotype linkage and association mapping based on but not limited to R/qtl (http://www.rqtl.org). All data can be uploaded and downloaded using simple delimited text or Excel formats and are accessible via a public web user interface for biologists and R statistic and web service interfaces for bioinformaticians, based on open source MOLGENIS and xQTL workbench software. WormQTL welcomes data submissions from other worm researchers.

  2. Effects of walls temperature variation on double diffusive natural convection of Al2O3-water nanofluid in an enclosure

    Science.gov (United States)

    Sheikhzadeh, G. A.; Dastmalchi, M.; Khorasanizadeh, H.

    2013-12-01

    The effect of wall temperature variations on double diffusive natural convection of Al2O3-water nanofluid in a differentially heated square enclosure with constant temperature hot and cold vertical walls is studied numerically. Transport mechanisms of nanoparticles including Brownian diffusion and thermophoresis that cause heterogeneity are considered in non-homogeneous model. The hot and cold wall temperatures are varied, but the temperature difference between them is always maintained 5 °C. The thermophysical properties such as thermal conductivity, viscosity and density and thermophoresis diffusion and Brownian motion coefficients are considered variable with temperature and volume fraction of nanoparticles. The governing equations are discretized using the control volume method. The results show that nanoparticle transport mechanisms affect buoyancy force and cause formation of small vortexes near the top and bottom walls of the cavity and reduce the heat transfer. By increasing the temperature of the walls the effect of transport mechanisms decreases and due to enhanced convection the heat transfer rate increases.

  3. Causes and consequences of range size variation: the influence of traits, speciation, and extinction

    Directory of Open Access Journals (Sweden)

    Steven M. Vamosi

    2012-12-01

    Full Text Available The tremendous variation in species richness observed among related clades across the tree of life has long caught the imagination of biologists. Recently, there has been growing attention paid to the possible contribution of range size variation, either alone or in combination with putative key innovations, to these patterns. Here, we review three related topics relevant to range size evolution, speciation, and extinction. First, we provide a brief overview of the debate surrounding patterns and mechanisms for phylogenetic signal in range size. Second, we discuss some recent findings regarding the joint influence of traits and range size on diversification. Finally, we present the preliminary results of a study investigating whether range size is negatively correlated with contemporary extinction risk in flowering plants.

  4. Metal accumulation in mosses across national boundaries: Uncovering and ranking causes of spatial variation

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Winfried [Landscape Ecology, University of Vechta, P.O. Box 1553, D-49364 Vechta (Germany)], E-mail: wschroeder@iuw.uni-vechta.de; Pesch, Roland [Landscape Ecology, University of Vechta, P.O. Box 1553, D-49364 Vechta (Germany)], E-mail: rpesch@iuw.uni-vechta.de; Englert, Cordula [Landscape Ecology, University of Vechta, P.O. Box 1553, D-49364 Vechta (Germany)], E-mail: cenglert@iuw.uni-vechta.de; Harmens, Harry [Centre for Ecology and Hydrology, Orton Building, Deiniol Road, Bangor, Gwynedd LL57 2UP (United Kingdom)], E-mail: hh@ceh.ac.uk; Suchara, Ivan [Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Kvetnove namesti 391, CZ 252 43 Pruhonice, Cz-252 43 Pruhonice (Czech Republic)], E-mail: suchara@vukoz.cz; Zechmeister, Harald G. [Department of Conservation Biology, Vegetation- and Landscape Ecology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna (Austria)], E-mail: harald.zechmeister@univie.ac.at; Thoeni, Lotti [FUB-Research Group for Environmental Monitoring, Untere Bahnhofstrasse 30, P.O. Box 1645, CH-8640 Rapperswil (Switzerland)], E-mail: lotti.thoeni@fub-ag.ch; Mankovska, Blanka [Institute of Landscape Ecology, Slovak Academy of Science, Stefanikova str. No. 3, P.O. Box 254, SK-814 99 Bratislava (Slovakia)], E-mail: bmankov@stonline.sk; Jeran, Zvonka [Department of Environmental Sciences, Institut Jozef Stefan, Jamova 39, 1000 Ljubljana (Slovenia)], E-mail: zvonka.jeran@ijs.si; Grodzinska, Krystyna [W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, PL-31512 Krakow (Poland)], E-mail: grodzin@ib-pan.krakow.pl; Alber, Renate [Environmental Agency of Bolzano, Via Sottomonte 2, 39055 Laives (Italy)], E-mail: renate.alber@provinz.bz.it

    2008-01-15

    This study aimed at cross-border mapping metal loads in mosses in eight European countries in 1990, 1995, and 2000 and at investigating confounding factors. Geostatistics was used for mapping, indicating high local variances but clear spatial autocorrelations. Inference statistics identified differences of metal concentrations in mosses on both sides of the national borders. However, geostatistical analyses did not ascertain discontinuities of metal concentrations in mosses at national borders due to sample analysis in different laboratories applying a range of analytical techniques. Applying Classification and Regression Trees (CART) to the German moss data as an example, the local variation in metal concentrations in mosses were proved to depend mostly on different moss species, potential local emission sources, canopy drip and precipitation. - Factors affecting the spatial variation in metal accumulation in mosses were mapped by geostatistics and ranked by CART.

  5. What constitutes a nesting attempt? Variation in criteria causes bias and hinders comparisons across studies

    Science.gov (United States)

    Garcia, V.; Conway, C.J.

    2009-01-01

    Because reliable estimates of nesting success are very important to avian studies, the definition of a "successful nest" and the use of different analytical methods to estimate success have received much attention. By contrast, variation in the criteria used to determine whether an occupied site that did not produce offspring contained a nesting attempt is a source of bias that has been largely ignored. This problem is especially severe in studies that deal with species whose nest contents are relatively inaccessible because observers cannot determine whether or not an egg was laid for a large proportion of occupied sites. Burrowing Owls (Athene cunicularia) often lay their eggs ???3 m below ground, so past Burrowing Owl studies have used a variety of criteria to determine whether a nesting attempt was initiated. We searched the literature to document the extent of that variation and examined how that variation influenced estimates of daily nest survival. We found 13 different sets of criteria used by previous authors and applied each criterion to our data set of 1,300 occupied burrows. We found significant variation in estimates of daily nest survival depending on the criteria used. Moreover, differences in daily nest survival among populations were apparent using some sets of criteria but not others. These inconsistencies may lead to incorrect conclusions and invalidate comparisons of the productivity and relative site quality among populations. We encourage future authors working on cavity-, canopy-, or burrow-nesting birds to provide specific details on the criteria they used to identify a nesting attempt. ?? 2009 by The American Ornithologists' Union. All rights reserved.

  6. Causes of Observed Long-Periodic Variations of the Polarization at Polar Regions of Jupiter

    CERN Document Server

    Shalygina, O S; Shalygin, E V; Marchenko, G P; Velikodsky, Y I; Akimov, L A; Starodubtseva, O M; Velikodsky, Yu. I.

    2006-01-01

    Data of 23-years of Jupiter polarimetric observations (1981- 2004) have been reprocessed using new improved technique. The data from other observers have been added to the analysis (1971-74). Anticorrelation between asymmetry of polarization and insolation has been found. The mechanism of influence of seasons changing (through temperature variations) on north-south asymmetry of polarization formation has been proposed. Also a possibility of existence of influence of solar cosmic rays flux on polarization value is noted.

  7. Long-term variation in the Sun's activity caused by magnetic Rossby waves in the tachocline

    CERN Document Server

    Zaqarashvili, T V; Hanslmeier, A; Carbonell, M; Ballester, J L; Gachechiladze, T; Usoskin, I G

    2015-01-01

    Long-term records of sunspot number and concentrations of cosmogenic radionuclides (10Be and 14C) on the Earth reveal the variation of the Sun's magnetic activity over hundreds and thousands of years. We identify several clear periods in sunspot, 10Be, and 14C data as 1000, 500, 350, 200 and 100 years. We found that the periods of the first five spherical harmonics of the slow magnetic Rossby mode in the presence of a steady toroidal magnetic field of 1200-1300 G in the lower tachocline are in perfect agreement with the time scales of observed variations. The steady toroidal magnetic field can be generated in the lower tachocline either due to the steady dynamo magnetic field for low magnetic diffusivity or due to the action of the latitudinal differential rotation on the weak poloidal primordial magnetic field, which penetrates from the radiative interior. The slow magnetic Rossby waves lead to variations of the steady toroidal magnetic field in the lower tachocline, which modulate the dynamo magnetic field ...

  8. The concept of crisis and denominations: types and causes of variations in the world economy crisis terminology

    Directory of Open Access Journals (Sweden)

    Manoel Messias Alves da Silva

    2016-06-01

    Full Text Available This paper aims at introducing the concept of crisis in the economic scope, its denominations in Brazilian Portuguese (BP and European Spanish (ES, concluding with its denominative variants in both languages, such as: economy crisis, 2008 crisis, major crisis and major globalization crisis; crisis económica, crisis de 2008, gran crisis e gran crisis de la globalización, respectively, searching to identify the types and causes of these variations. These variants, as fragments, already proposed by Freixa (2014, present the following types: morph syntax variations which are related to an inferior lexicon character, being either by alteration in its syntagmatic structure or by maintenance or change of gender or number; lexicon – may be considered the synonymy itself, since there is total change between both lexical units which will produce the same meaning. Among the causes already proposed by the author (Freixa, 2014, only the following causes will be considered: the functional one, which is constituted by different communicative registers; the stylist icon, which is related to the author’s communicative options and needs. The types and causes of variations will be in traduced, exemplified and analyzed according to the contexts collected from the Brazilian and Spanish corpora, which integrates the Project Valores culturais e didáticos na metáfora de especialidade: as múltiplas imagens da crise econômica mundial na imprensa escrita (Cultural and Didactic Values in the specialty metaphor: multiple images of the world economy crisis in the written midia – an integrated research Project by USP – University of São Paulo, UEM – State University of Maringa, Unesp and University of Vigo, funded by CAPES/DGPU. As a conclusion, it was observed that the search for denominative variants has been relevant to introduce an in vivo terminology because the case of economical crisis concept and its denominations shows that variations found

  9. Daily variations in ambulance calls for selected causes in Arkhangelsk, Russia: potential role of excessive alcohol consumption on weekends

    Directory of Open Access Journals (Sweden)

    Sergei N. Drachev

    2012-11-01

    Full Text Available Objectives. To assess daily variations in ambulance calls for cardiovascular diseases (CVDs, mental and behavioral disorders, and external causes in Arkhangelsk, Northwest Russia, in 2000–2008. Study design. A population-based study. Methods. Data about all ambulance calls during the years 2000–2008 were obtained from the Arkhangelsk ambulance station. Information about patient's gender, age, doctor's diagnosis according to International Classification of Diseases, 10th revision, and the date of call were recorded. Pearson's Chi-squared tests were used for comparing proportions of ambulance calls across the week for CVDs (I00-99, mental and behavioral disorders (F00-F99, and external causes (S00-T98, V01-Y98. The ratio of incidence of ambulance calls on Saturday, Sunday, and Monday versus the rest of week was also calculated. Results. There is a significant daily variation (p < 0.001 in calls for CVDs in men and women aged 18–59 and women aged 60 years and older, with increased numbers of calls on weekends and Mondays varying between 2 and 3% excess calls. For mental and behavioral disorders, a similar pattern was found in the age group of 18–59 year-olds. Ratios for the number of calls during weekends and Mondays vs. the rest of the week were 1.05 (95% CI: 1.02–1.08 among women and 1.02 (95% CI: 1.00–1.05 among men. For external causes, a significant variation and an increase in ambulance calls during Saturdays, Sundays, and Mondays from 4 to 17% excess calls was observed for both age and gender groups. Conclusions. The observed daily variations in ambulance calls with an increased number of calls on weekends and Mondays for CVDs, mental and behavioral disorders, and external causes may be associated with excessive alcohol consumption on the weekends. Further research using data on individual levels of alcohol consumption are warranted.

  10. Neutrons reveal how nature uses structural themes and variation in biological regulation

    Energy Technology Data Exchange (ETDEWEB)

    Trewhella, Jill [School of Molecular and Microbial Biosciences, University of Sydney, Sydney 2006 (Australia)]. E-mail: jtrewhella@usyd.edu.au

    2006-11-15

    Healthy cellular function requires tight regulation of a multitude of bio-molecular interactions and processes, often in response to external stimuli. In achieving this regulation, nature uses a number of 'second messengers' that are released inside cells in response to first messengers, such as hormones that bind to the cell surface. Divalent calcium and cyclic nucleotides, like cAMP, are among nature's second messengers that bind to receptor proteins inside cells order to regulate the activities of various targets, including many protein kinases. Kinases are enzymes that catalyze the attachment of phosphate groups to proteins in order to modulate their functions. We have been using neutron contrast variation and small-angle solution scattering to study the interactions of the second messenger receptor proteins and their regulatory targets in order to understand the structural basis for these complex processes that use a number of common structural motifs to accomplish highly regulated function. Our most recent work has focused on the different isoforms of the cAMP-dependent protein kinase and the muscle regulatory complex troponin.

  11. Variation in performance of surfactant loading and resulting nitrate removal among four selected natural zeolites.

    Science.gov (United States)

    Guan, Huade; Bestland, Erick; Zhu, Chuanyu; Zhu, Honglin; Albertsdottir, Dora; Hutson, John; Simmons, Craig T; Ginic-Markovic, Milena; Tao, Xian; Ellis, Amanda V

    2010-11-15

    Surfactant modified zeolites (SMZs) have the capacity to target various types of water contaminants at relatively low cost and thus are being increasingly considered for use in improving water quality. It is important to know the surfactant loading performance of a zeolite before it is put into application. In this work we compare the loading capacity of a surfactant, hexadecyltrimethylammonium bromide (HDTMA-Br), onto four natural zeolites obtained from specific locations in the USA, Croatia, China, and Australia. The surfactant loading is examined using thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, and Raman spectroscopy. We then compare the resulting SMZs performance in removing nitrate from water. Results show that TGA is useful to determine the HDTMA loading capacity on natural zeolites. It is also useful to distinguish between a HDTMA bi-layer and a HDTMA mono-layer on the SMZ surface, which has not been previously reported in the literature. TGA results infer that HDTMA (bi-layer) loading decreases in the order of US zeolite>Croatian zeolite>Chinese zeolite>Australian zeolite. This order of loading explains variation in performance of nitrate removal between the four SMZs. The SMZs remove 8-18 times more nitrate than the raw zeolites. SMZs prepared from the selected US and Croatian zeolites were more efficient in nitrate removal than the two zeolites commercially obtained from Australia and China.

  12. HIV-1 Tat and Viral Latency: What We Can Learn from Naturally Occurring Sequence Variations

    Science.gov (United States)

    Kamori, Doreen; Ueno, Takamasa

    2017-01-01

    Despite the effective use of antiretroviral therapy, the remainder of a latently HIV-1-infected reservoir mainly in the resting memory CD4+ T lymphocyte subset has provided a great setback toward viral eradication. While host transcriptional silencing machinery is thought to play a dominant role in HIV-1 latency, HIV-1 protein such as Tat, may affect both the establishment and the reversal of latency. Indeed, mutational studies have demonstrated that insufficient Tat transactivation activity can result in impaired transcription of viral genes and the establishment of latency in cell culture experiments. Because Tat protein is one of highly variable proteins within HIV-1 proteome, it is conceivable that naturally occurring Tat mutations may differentially modulate Tat functions, thereby influencing the establishment and/or the reversal of viral latency in vivo. In this mini review, we summarize the recent findings of Tat naturally occurring polymorphisms associating with host immune responses and we highlight the implication of Tat sequence variations in relation to HIV latency.

  13. The Expanding Family of Natural Anion Channelrhodopsins Reveals Large Variations in Kinetics, Conductance, and Spectral Sensitivity

    Science.gov (United States)

    Govorunova, Elena G.; Sineshchekov, Oleg A.; Rodarte, Elsa M.; Janz, Roger; Morelle, Olivier; Melkonian, Michael; Wong, Gane K.-S.; Spudich, John L.

    2017-01-01

    Natural anion channelrhodopsins (ACRs) discovered in the cryptophyte alga Guillardia theta generate large hyperpolarizing currents at membrane potentials above the Nernst equilibrium potential for Cl− and thus can be used as efficient inhibitory tools for optogenetics. We have identified and characterized new ACR homologs in different cryptophyte species, showing that all of them are anion-selective, and thus expanded this protein family to 20 functionally confirmed members. Sequence comparison of natural ACRs and engineered Cl−-conducting mutants of cation channelrhodopsins (CCRs) showed radical differences in their anion selectivity filters. In particular, the Glu90 residue in channelrhodopsin 2, which needed to be mutated to a neutral or alkaline residue to confer anion selectivity to CCRs, is nevertheless conserved in all of the ACRs identified. The new ACRs showed a large variation of the amplitude, kinetics, and spectral sensitivity of their photocurrents. A notable variant, designated “ZipACR”, is particularly promising for inhibitory optogenetics because of its combination of larger current amplitudes than those of previously reported ACRs and an unprecedentedly fast conductance cycle (current half-decay time 2–4 ms depending on voltage). ZipACR expressed in cultured mouse hippocampal neurons enabled precise photoinhibition of individual spikes in trains of up to 50 Hz frequency. PMID:28256618

  14. Natural variation in petal color in Lycoris longituba revealed by anthocyanin components.

    Directory of Open Access Journals (Sweden)

    Qiuling He

    Full Text Available Lycoris longituba is one of the species belonging to the Amaryllidaceae family. Despite its limited distribution, endemic to central eastern China, this species displays an exceptionally wide diversity of flower colors from purple, red, orange, to yellow, in nature. We study the natural variation of floral color in L. longituba by testing the components of water-soluble vacuolar pigments--anthocyanins--in its petals using high-performance liquid chromatography coupled with photodiode array detection and electrospray ionization mass spectrometry. Four anthocyanins were identified, cyanidin-3-sophoroside (Cy3So, cyanidin-3-xylosylglucoside (Cy3XyGlc, cyanidin-3-sambubioside (Cy3Sa, and pelargonidin-3-xylosylglucoside (Pg3XyGlc, which occur at various amounts in L. longituba petals of different colors. A multivariate analysis was used to explore the relationship between pigments and flower color. Anthocyanins have been thought to play a major role in acting as a UV screen that protects the plant's DNA from sunlight damage and attracting insects for the purpose of pollination. Thus, knowledge about the content and type of anthocyanins determining the petal coloration of Lycoris longituba will help to study the adaptive evolution of flowers and provide useful information for the ornamental breeding of this species.

  15. Natural variation in petal color in Lycoris longituba revealed by anthocyanin components.

    Science.gov (United States)

    He, Qiuling; Shen, Ye; Wang, Mingxiu; Huang, Minren; Yang, Ruizhen; Zhu, Shuijin; Wang, Liangsheng; Xu, Yanjun; Wu, Rongling

    2011-01-01

    Lycoris longituba is one of the species belonging to the Amaryllidaceae family. Despite its limited distribution, endemic to central eastern China, this species displays an exceptionally wide diversity of flower colors from purple, red, orange, to yellow, in nature. We study the natural variation of floral color in L. longituba by testing the components of water-soluble vacuolar pigments--anthocyanins--in its petals using high-performance liquid chromatography coupled with photodiode array detection and electrospray ionization mass spectrometry. Four anthocyanins were identified, cyanidin-3-sophoroside (Cy3So), cyanidin-3-xylosylglucoside (Cy3XyGlc), cyanidin-3-sambubioside (Cy3Sa), and pelargonidin-3-xylosylglucoside (Pg3XyGlc), which occur at various amounts in L. longituba petals of different colors. A multivariate analysis was used to explore the relationship between pigments and flower color. Anthocyanins have been thought to play a major role in acting as a UV screen that protects the plant's DNA from sunlight damage and attracting insects for the purpose of pollination. Thus, knowledge about the content and type of anthocyanins determining the petal coloration of Lycoris longituba will help to study the adaptive evolution of flowers and provide useful information for the ornamental breeding of this species.

  16. Natural-Cause Mortality and Long-Term Exposure to Particle Components

    DEFF Research Database (Denmark)

    Beelen, Rob; Hoek, Gerard; Raaschou-Nielsen, Ole;

    2015-01-01

    standardized protocol. Annual average concentrations of Copper (Cu), Iron (Fe), Potassium (K), Nickel (Ni), Sulfur (S), Silicon (Si), Vanadium (V) and Zinc (Zn) within PM size fractions 2.5 µm (PM2.5) and ...-up 14.3 years). Hazard ratios were positive for almost all elements and statistically significant for PM2.5 sulfur (1.14; 95% CI: 1.06, 1.23 per 200 ng/m3). In a two-pollutant model, the association with PM2.5 sulfur was robust to adjustment for PM2.5 mass, whereas the association with PM2.5 mass...... was reduced. CONCLUSIONS: Long-term exposure to PM2.5 sulfur was associated with natural cause mortality. This association was robust to adjustment for other pollutants and PM2.5....

  17. Inter-decadal variations,causes and future projection of the Asian summer monsoon

    Institute of Scientific and Technical Information of China (English)

    Ding Yihui; Si Dong; Sun Ying; Liu Yanju; Song Yafang

    2014-01-01

    The present paper presents a concise summary of our recent studies on the Asian summer monsoon, with highting decadal and inter-decadal scales. The studies on the long-term variations of the Asian summer monsoon and its impacts on the change in the summer precipitation in China are reviewed. Moreover,recent changes in the Asian summer monsoon and summer precipitation in East Asia (including Meiyu precipitation) are discussed. Finally,the future changes of the Asian summer monsoon are also pointed out in this paper.

  18. Hydrophilic fraction of natural organic matter causing irreversible fouling of microfiltration and ultrafiltration membranes.

    Science.gov (United States)

    Yamamura, Hiroshi; Okimoto, Kenji; Kimura, Katsuki; Watanabe, Yoshimasa

    2014-05-01

    Although membrane filtration is a promising technology in the field of drinking water treatment, persistent membrane fouling remains a major disadvantage. For more efficient operation, causative agents of membrane fouling need to be identified. Membrane fouling can be classified into physically reversible and irreversible fouling on basis of the removability of the foulants by physical cleaning. Four types of natural organic matter (NOM) in river water used as a source of drinking water were fractionated into hydrophobic and hydrophilic fractions, and their potential to develop irreversible membrane fouling was evaluated by a bench-scale filtration experiment together with spectroscopic and chromatographic analyses. In this study, only dissolved NOM was investigated without consideration of interactions of NOM fractions with particulate matter. Results demonstrated that despite identical total organic carbon (TOC), fouling development trends were significantly different between hydrophilic and hydrophobic fractions. The hydrophobic fractions did not increase membrane resistance, while the hydrophilic fractions caused severe loss of membrane permeability. These results were identical with the case when the calcium was added to hydrophobic and hydrophilic fractions. The largest difference in NOM characteristics between hydrophobic and hydrophilic fractions was the presence or absence of macromolecules; the primary constituent causing irreversible fouling was inferred to be "biopolymers", including carbohydrates and proteins. In addition, the results demonstrated that the extent of irreversible fouling was considerably different depending on the combination of membrane materials and NOM characteristics. Despite identical nominal pore size (0.1 μm), a polyvinylidene fluoride (PVDF) membrane was found to be more rapidly fouled than a PE membrane. This is probably explained by the generation of strong hydrogen bonding between hydroxyl groups of biopolymers and fluorine

  19. Variation at the transcriptional level among Chinese natural populations of Arabidopsis thaliana in response to cold stress

    Institute of Scientific and Technical Information of China (English)

    HE Fei; KANG JiuQing; ZHOU Xin; SU Zhen; QU LiJia; GU HongYa

    2008-01-01

    The Arabidopsis 25K GeneChip (ATH1, Affymetrix) was used to make a survey of the variation of the transcriptional profiles among 5 Chinese natural populations of Arabidopsis thaliana under cold treatment. In normal growth condition, the expression level of 2.26% (513 genes in the population from Jiujiang, Jiangxi, JXjjx)to 6.52% (1482 genes in the population from Tongliang, Chongqing, CQtlx) genes was 2-fold higher than that of Col ecotype. Under cold treatment, the expression of 12.84% (2920 genes in the population from Chenggu, Shaanxi, SXcgx) to 19.46% (4426 genes in the population from Qinghe, Xinjiang, XJqhx) genes was up- or down-regulated by at least two-fold that of their controls. In general, most of up-regulated genes might be the genes essential for plant surviving at low temperature, such as genes in CBF pathway and the genes responsible for synthesizing molecules accumulated for cold tolerance. However, each natural population had some specific genes induced under cold treat-ment. The data indicated that some of the cold-responding genes were differentiated among the popu-lations distributed in the natural habitats with different climate conditions. CBF3, one of the key tran-scription factor genes in cold responding pathway, showed significant differences in expression among populations. The sequence analysis indicated that the changes in its regulation region caused the dramatic difference in the expression pattern. Further studies on the correlation of the function of the differentially expressed genes and the cold tolerance in different populations may provide some new insight into the molecular mechanism of adaptation to local environment in Arabidopsis thaliana in China.

  20. Oscillations in the power spectra of motor unit signals caused by refractoriness variations

    Science.gov (United States)

    Hu, X. L.; Tong, K. Y.; Hung, L. K.

    2004-09-01

    The refractory period of a motor unit is an important mechanism that regulates the motor unit firing, and its variation has been found in many physiological cases. In this study, a new observation that an increase in the motor unit refractoriness results in an enhancement of oscillations, or ripple effects, in the motor unit output power density spectra (PDS) has been identified and studied. The effects of the refractoriness variation on the PDS of motor unit firing were investigated on three levels: theoretical modeling, simulation and electromyographic (EMG) experimentation on human subjects. Both theoretical modeling and simulation showed the enhanced oscillations, ripple effects, in MUAPT PDS, given the increase in the refractoriness. It was also found that the extent of the increment in output PDS oscillation could be related to the motor unit size and the mean firing rate of the stimulation. A needle EMG experiment on biceps brachii muscles of five healthy human subjects was carried out during isometric contraction at 20% maximum voluntary contraction (MVC) for 20 s with a fatigue effort proceeded by MVC. The increased oscillations in the PDS of the real MUAPTs were observed with the rising of the motor unit refractoriness due to fatigue. The study gives new information for EMG spectra interpretation, and also provides a potential method for accessing neuromuscular transmission failure (NTF) due to fatigue during voluntary contraction.

  1. WHAT CAUSES THE INTER-SOLAR-CYCLE VARIATION OF TOTAL SOLAR IRRADIANCE?

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, N. B.; Kong, D. F., E-mail: nanbin@ynao.ac.cn [National Astronomical Observatories/Yunnan Observatory, CAS, Kunming 650011 (China)

    2015-12-15

    The Physikalisch Meteorologisches Observatorium Davos total solar irradiance (TSI), Active Cavity Radiometer Irradiance Monitoring TSI, and Royal Meteorological Institute of Belgium TSI are three typical TSI composites. Magnetic Plage Strength Index (MPSI) and Mount Wilson Sunspot Index (MWSI) should indicate the weak and strong magnetic field activity on the solar full disk, respectively. Cross-correlation (CC) analysis of MWSI with three TSI composites shows that TSI should be weakly correlated with MWSI, and not be in phase with MWSI at timescales of solar cycles. The wavelet coherence (WTC) and partial wavelet coherence (PWC) of TSI with MWSI indicate that the inter-solar-cycle variation of TSI is also not related to solar strong magnetic field activity, which is represented by MWSI. However, CC analysis of MPSI with three TSI composites indicates that TSI should be moderately correlated and accurately in phase with MPSI at timescales of solar cycles, and that the statistical significance test indicates that the correlation coefficient of three TSI composites with MPSI is statistically significantly higher than that of three TSI composites with MWSI. Furthermore, the cross wavelet transform (XWT) and WTC of TSI with MPSI show that the TSI is highly related and actually in phase with MPSI at a timescale of a solar cycle as well. Consequently, the CC analysis, XWT, and WTC indicate that the solar weak magnetic activity on the full disk, which is represented by MPSI, dominates the inter-solar-cycle variation of TSI.

  2. Protective effect of natural flavonoids on rat peritoneal macrophages injury caused by asbestos fibers.

    Science.gov (United States)

    Kostyuk, V A; Potapovich, A I; Speransky, S D; Maslova, G T

    1996-01-01

    Exposure of macrophages to asbestos fibers resulted in enhancement of the production of oxygen radicals, determined by a lucigenin enhanced chemiluminescence (LEC) assay, a formation of thiobarbituric acid reactive substances (TBARS), a LDH release into the incubation mixture, and a rapid lysis of the cells. Rutin (Rut) and quercetin (Qr) were effective in inhibiting LEC, TBARS formation, and reducing peritoneal macrophages injury caused by asbestos. The concentrations pre-treatment of antioxidants that were required to prevent the injury of peritoneal macrophages caused by asbestos by 50% (IC50) were 90 microM and 290 microM for Qr and Rut, respectively. Both flavonoids were found to be oxidized during exposure of peritoneal macrophages to asbestos and the oxidation was SOD sensitive. The efficacy of flavonoids as antioxidant agents as well as superoxide ion scavengers was also evaluated using appropriate model systems, and both quercetin and rutin were found to be effective in scavenging O2.-. These findings indicate that flavonoids are able to prevent the respiratory burst in rat peritoneal macrophages exposed to asbestos at the stage of activated oxygen species generation, mainly as superoxide scavengers. On the basis of this study it was concluded that natural flavonoids quercetin and rutin would be promising drug candidates for a prophylactic asbestos-induced disease.

  3. Spatial variations in daily average CO2 concentrations above wetland surface of Xianghai National Nature Reserve, China

    Institute of Scientific and Technical Information of China (English)

    BAI Jun-hong; OUYANG Hua; WANG Qing-gai; ZHOU Cai-ping; XU Xiao-feng

    2005-01-01

    Horizontal and vertical variations of daily average CO2 concentration above the wetland surface were studied in Xianghai National Nature Reserve of China in August, 2000. The primary purpose was to study spatial distribution characteristics of CO2 concentration on the four levels of height(0. 1 m, 0.6 m, 1.2 m and 2 m) and compare the differences of CO2 concentration under different land covers. Results showed that daily average CO2 concentration above wetland surface in Xianghai National Natural Reserve was lower than that above other wetlands in northeast China as well as the worldwide average, suggesting that Xianghai wetland absorbed CO2 in August and acted as"sink" of CO2. The horizontal variations on the four levels of height along the latitude were distinct, and had the changing tendency of"decreasing after increasing" with the increase of height. The areas with obvious variations were consistent on different levels of height,and those with the highest variations appeared above surface of shore, sloping field, Typha wetland and Phragmites wetland; the vertical variations were greatly different, with the higher variations in Phragmites wetland and Typha wetland, and the lands near the shore and the sloping field with the lower variations. Spatial variations of daily average CO2 concentrations above wetland surface were affected by surface qualities and land covers.

  4. Perturbations of flows of incompressible nonlinearly viscous and viscoplastic fluids caused by variations in material functions

    Science.gov (United States)

    Georgievskii, D. V.

    2007-06-01

    Material functions are necessary element of the constitutive relations determining any model of continuum. These functions can be defined as a collection of objects from which the operator of constitutive relations can be reconstructed completely. The material functions are found in test experiments and show the differences between a given medium and other media in the framework of the same model [1]. The "test experiment theory" is an important part of modern experimental mechanics. Just as in any experiment, from determining the viscosity coefficient by using the rotational viscosimeters to constructing the yield surface by using machines combined loading, the material functions are determined with an unavoidable error. For example, experimenters know that, in experiments with arbitrary accuracy, the moduli of elasticity can only be measured with an unimprovable tolerance of about 7%. Starting already from [2], the investigators' attention has been repeatedly drawn to the fact that it is necessary to take into account this tolerance in determining the material constants, functions, and functionals in problems of mechanics and especially in analyzing the stability of deformation processes. Mathematically, this means that problems of stability under perturbations of the initial data, external constantly acting forces, domain boundaries, etc. should be supplemented with the assumption that the material functions have unknown perturbations of a certain class [3]. The variations of material functions in the framework of the linearized stability theory were considered in [2, 4, 5]. In what follows, we study isotropic tensor functions in the most general case of scalar and tensor nonlinearity. These functions are assigned the meaning of constitutive relations between the stress and strain rate tensors in continuum. These constitutive relations contain scalar material functions of invariants on which, as follows from the above, some variations proportional to a small

  5. [Pyrimidal syndrome and anatomical variations as a cause of insidious sciatic pain].

    Science.gov (United States)

    Ortiz Sánchez, V E; Charco Roca, L M; Soria Quiles, A; Zafrilla Disla, E; Hernandez Mira, F

    2014-11-01

    The case is presented of a 42 year old woman who had been suffering a loss of strength in her left leg for six years. After an extensive diagnostic study, the pain was classified as of functional origin by a diagnosis of exclusion. Since then, the patient has tried all kind of drug treatments and conservative techniques without improvement. After an exhaustive study with inconclusive results, the case was discussed with the Orthopaedics Department, who performed an exploratory surgery, in which compression of the sciatic nerve due to an anatomical variation of the piriformis muscle was observed. Part of the muscle was resected during surgery and the sciatic nerve was freed, after which the patient experienced a great improvement.

  6. Color variations of AR coatings caused by a leached layer on the substrate.

    Science.gov (United States)

    Guenther, K H

    1981-01-01

    Color differences of AR-coated prisms were found to be due to a surface layer with a refractive index of n = 1.46 and a geometrical thickness of ~41 nra on the glass substrate (BaK4, n = 1.5688). The existence of this layer is demonstrated by reflection spectroscopy measurements together with numerical calculations of the spectral reflectance of both the uncoated and coated substrates. Auger electron spectroscopy depth profiling analyses reveal that the Ba content of the glass had been leached out completely in the layer. The leaching process was caused by an improper cleaning agent used with the uncoated prisms in the optical shop. In addition to its inherent optical interference effect, the leached substrate surface seems to influence the condensation and growth of the first layer of AR coatings deposited onto it thus causing additional changes of the spectral characteristics of the coating.

  7. Some causes of inter-laboratory variation in the results of comet assay.

    Science.gov (United States)

    Sirota, Nikolai P; Zhanataev, Aliy K; Kuznetsova, Elena A; Khizhnyak, Eugenii P; Anisina, Elena A; Durnev, Andrei D

    2014-08-01

    We performed an inter-laboratory study to determine the variation of comet assay results and to identify its possible reasons. An exchange of slides between Labs in different stages of the comet assay protocol was performed. Because identical slides, durations of alkali treatment and electrophoresis, and similar electric field strengths (2.0 V/cm and 2.14 V/cm) were used, we concluded that the observed inter-laboratory difference in the results is directly associated with the electrophoresis step. In Lab 1, mouse bone marrow cells were exposed to methyl methanesulfonate at concentrations of 10, 25 and 50 μM for 3 h at 37 °C. In Lab 2, cells the same as in Lab 1 were immobilized in LMA on slides and exposed to X-rays at doses of 3-8 Gy. We found that the transportation of slides after lysis or electrophoresis step, as well as different dyes used for scoring did not produce any significant effect on the results. No substantial difference in the data was also revealed when various software packages were used for image analysis. The temperature of the alkaline solution was shown to increase during electrophoresis and, besides, the temperature heterogeneity of the solution took place in the area of the platform, with a maximum in the middle of the chamber. The temperature heterogeneity could affect the rate of conversion of alkali labile sites into single stranded breaks. Thus, it was clearly indicated that real temperature variations during the alkali treatment and electrophoresis were an essential factor in the variability of the results between our Labs.

  8. Propionic and Methylmalonic Acidemia: Antisense Therapeutics for Intronic Variations Causing Aberrantly Spliced Messenger RNA

    OpenAIRE

    Rincón, A. ; Aguado, C. ; Desviat, L. R. ; Sánchez-Alcudia, R. ; Ugarte, M. ; Pérez, B. 

    2007-01-01

    We describe the use of antisense morpholino oligonucleotides (AMOs) to restore normal splicing caused by intronic molecular defects identified in methylmalonic acidemia (MMA) and propionic acidemia (PA). The three new point mutations described in deep intronic regions increase the splicing scores of pseudoexons or generate consensus binding motifs for splicing factors, such as SRp40, which favor the intronic inclusions in MUT (r.1957ins76), PCCA (r.1284ins84), or PCCB (r.654ins72) messenger R...

  9. Natural variation in SAR11 marine bacterioplankton genomes inferred from metagenomic data

    Directory of Open Access Journals (Sweden)

    Wilhelm Larry J

    2007-11-01

    Full Text Available Abstract Background One objective of metagenomics is to reconstruct information about specific uncultured organisms from fragmentary environmental DNA sequences. We used the genome of an isolate of the marine alphaproteobacterium SAR11 ('Candidatus Pelagibacter ubique'; strain HTCC1062, obtained from the cold, productive Oregon coast, as a query sequence to study variation in SAR11 metagenome sequence data from the Sargasso Sea, a warm, oligotrophic ocean gyre. Results The average amino acid identity of SAR11 genes encoded by the metagenomic data to the query genome was only 71%, indicating significant evolutionary divergence between the coastal isolates and Sargasso Sea populations. However, an analysis of gene neighbors indicated that SAR11 genes in the Sargasso Sea metagenomic data match the gene order of the HTCC1062 genome in 96% of cases (> 85,000 observations, and that rearrangements are most frequent at predicted operon boundaries. There were no conserved examples of genes with known functions being found in the coastal isolates, but not the Sargasso Sea metagenomic data, or vice versa, suggesting that core regions of these diverse SAR11 genomes are relatively conserved in gene content. However, four hypervariable regions were observed, which may encode properties associated with variation in SAR11 ecotypes. The largest of these, HVR2, is a 48 kb region flanked by the sole 5S and 23S genes in the HTCC1062 genome, and mainly encodes genes that determine cell surface properties. A comparison of two closely related 'Candidatus Pelagibacter' genomes (HTCC1062 and HTCC1002 revealed a number of "gene indels" in core regions. Most of these were found to be polymorphic in the metagenomic data and showed evidence of purifying selection, suggesting that the same "polymorphic gene indels" are maintained in physically isolated SAR11 populations. Conclusion These findings suggest that natural selection has conserved many core features of SAR11

  10. Shifting patterns of natural variation in the nuclear genome of caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Okamoto Kazufusa

    2011-06-01

    Full Text Available Abstract Background Genome wide analysis of variation within a species can reveal the evolution of fundamental biological processes such as mutation, recombination, and natural selection. We compare genome wide sequence differences between two independent isolates of the nematode Caenorhabditis elegans (CB4856 and CB4858 and the reference genome (N2. Results The base substitution pattern when comparing N2 against CB4858 reveals a transition over transversion bias (1.32:1 that is not present in CB4856. In CB4856, there is a significant bias in the direction of base substitution. The frequency of A or T bases in N2 that are G or C bases in CB4856 outnumber the opposite frequencies for transitions as well as transversions. These differences were not observed in the N2/CB4858 comparison. Similarly, we observed a strong bias for deletions over insertions in CB4856 (1.44: 1 that is not present in CB4858. In both CB4856 and CB4858, there is a significant correlation between SNP rate and recombination rate on the autosomes but not on the X chromosome. Furthermore, we identified numerous significant hotspots of variation in the CB4856-N2 comparison. In both CB4856 and CB4858, based on a measure of the strength of selection (ka/ks, all the chromosomes are under negative selection and in CB4856, there is no difference in the strength of natural selection in either the autosomes versus X or between any of the chromosomes. By contrast, in CB4858, ka/ks values are smaller in the autosomes than in the X chromosome. In addition, in CB4858, ka/ks values differ between chromosomes. Conclusions The clear bias of deletions over insertions in CB4856 suggests that either the CB4856 genome is becoming smaller or the N2 genome is getting larger. We hypothesize the hotspots found represent alleles that are shared between CB4856 and CB4858 but not N2. Because the ka/ks ratio in the X chromosome is higher than the autosomes on average in CB4858, purifying selection is

  11. Does variability matter? Major histocompatibility complex (MHC) variation and its associations to parasitism in natural small mammal populations

    OpenAIRE

    Meyer-Lucht, Yvonne

    2009-01-01

    The adaptive evolutionary potential of a species or population to cope with omnipresent environmental challenges is based on its genetic variation. Variability at immune genes, such as the major histocompatibility complex (MHC) genes, is assumed to be a very powerful and effective tool to keep pace with diverse and rapidly evolving pathogens. In my thesis, I studied natural levels of variation at the MHC genes, which have a key role in immune defence, and parasite burden in different small ma...

  12. Mutations in CHD7 in patients with CHARGE syndrome cause T-B + natural killer cell + severe combined immune deficiency and may cause Omenn-like syndrome.

    NARCIS (Netherlands)

    Gennery, A.R.; Slatter, M.A.; Rice, J.; Hoefsloot, L.H.; Barge, D.; McLean-Tooke, A.; Montgomery, T.; Goodship, J.A.; Burt, A.D.; Flood, T.J.; Abinun, M.; Cant, A.J.; Johnson, D.

    2008-01-01

    More than 11 genetic causes of severe combined immunodeficiency (SCID) have been identified, affecting development and/or function of T lymphocytes, and sometimes B lymphocytes and natural killer (NK) cells. Deletion of 22q11.2 is associated with immunodeficiency, although less than 1% of cases are

  13. Natural variations in expression of regulatory and detoxification related genes under limiting phosphate and arsenate stress in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Tapsi eShukla

    2015-10-01

    Full Text Available Abiotic stress including nutrient deficiency and heavy metal toxicity severely affects plant growth, development, and productivity. Genetic variations within and in between species are one of the important factors in establishing interactions and responses of plants with the environment. In the recent past, natural variations in Arabidopsis thaliana have been used to understand plant development and response towards different stresses at genetic level. Phosphorus (Pi deficiency negatively affects plant growth and metabolism and modulates expression of the genes involved in Pi homeostasis. Arsenate, As(V, a chemical analogue of Pi, is taken up by the plants via phosphate transport system. Studies suggest that during Pi deficiency, enhanced As(V uptake leads to increased toxicity in plants. Here, the natural variations in Arabidopsis have been utilized to study the As(V stress response under limiting Pi condition. The primary root length was compared to identify differential response of three Arabidopsis accessions (Col-0, Sij-1 and Slavi-1 under limiting Pi and As(V stress. To study the molecular mechanisms responsible for the differential response, comprehensive expression profiling of the genes involved in uptake, detoxification and regulatory mechanisms was carried out. Analysis suggests genetic variation-dependent regulatory mechanisms may affect differential response of Arabidopsis natural variants towards As(V stress under limiting Pi condition. Therefore, it is hypothesized that detailed analysis of the natural variations under multiple stress conditions might help in the better understanding of the biological processes involved in stress tolerance and adaptation.

  14. Measuring gravity change caused by water storage variations: Performance assessment under controlled conditions

    DEFF Research Database (Denmark)

    Christiansen, Lars; Lund, Sanne; Andersen, Ole Baltazar;

    2011-01-01

    Subsurface water content is an important state variable in hydrological systems. Established methods to measure subsurface water content have a small support scale which causes scaling problems in many applications. Time-lapse relative gravimetry can give an integrated measure of soil water storage...... changes over tens to hundreds of cubic meters. The use of time-lapse gravimetry in hydrology has until recent years been limited by the large efforts required to obtain precise and accurate gravity data at the 1μGal (10−8ms−2) scale. A typical modern relative gravimeter, the Scintrex CG-5, has...

  15. Large-scale geographical variation confirms that climate change causes birds to lay earlier.

    Science.gov (United States)

    Both, Christiaan; Artemyev, Aleksandr V; Blaauw, Bert; Cowie, Richard J; Dekhuijzen, Aarnoud J; Eeva, Tapio; Enemar, Anders; Gustafsson, Lars; Ivankina, Elena V; Järvinen, Antero; Metcalfe, Neil B; Nyholm, N Erik I; Potti, Jaime; Ravussin, Pierre-Alain; Sanz, Juan Jose; Silverin, Bengt; Slater, Fred M; Sokolov, Leonid V; Török, János; Winkel, Wolfgang; Wright, Jonathan; Zang, Herwig; Visser, Marcel E

    2004-08-22

    Advances in the phenology of organisms are often attributed to climate change, but alternatively, may reflect a publication bias towards advances and may be caused by environmental factors unrelated to climate change. Both factors are investigated using the breeding dates of 25 long-term studied populations of Ficedula flycatchers across Europe. Trends in spring temperature varied markedly between study sites, and across populations the advancement of laying date was stronger in areas where the spring temperatures increased more, giving support to the theory that climate change causally affects breeding date advancement.

  16. Genetic and environmental causes of variation in perceived loneliness in young people.

    Science.gov (United States)

    Waaktaar, Trine; Torgersen, Svenn

    2012-07-01

    Loneliness is prevalent in adolescence, despite the widespread expectation directed to young people to start building close relationships beyond the nuclear family. The aim of the present study was to explore the causal genetic and environmental structure behind variability in adolescents' perceived loneliness. Seven national cohorts (ages 12-18 years) of Norwegian twins reared together (1,394 twin pairs) participated. Perceived loneliness was measured with five items from the UCLA Loneliness Scale. Data were collected from mothers, fathers, and twins' self ratings by means of a posted questionnaire. Biometric analyses were applied, testing the causal architecture of loneliness within a psychometric model with one common latent factor in addition to specific genetic and environmental sources influencing the scores of each informant. The results showed a heritability (h(2)) of 75% on the latent perceived loneliness factor, and nonshared environmental effects (e(2)) explaining the remaining 25% of the latent factor variance. There were also significant rater-specific genetic and nonshared environmental effects. No shared environmental effects were found in the model, and there were no sex differences in the estimates. This study showed that variation in perceived loneliness in adolescents is highly genetic. Additional genetic and nonshared environmental etiological sources are to some extent represented in the scores of the specific rater.

  17. Untangling the Nature of Spatial Variations of Cold Dust Properties in Star Forming Galaxies

    CERN Document Server

    Kirkpatrick, Allison; Kennicutt, Robert; Galametz, Maud; Gordon, Karl; Groves, Brent; Hunt, Leslie; Dale, Daniel; Hinz, Joannah; Tabatabaei, Fatemeh

    2014-01-01

    We investigate the far-infrared (IR) dust emission for 20 local star forming galaxies from the Key Insights on Nearby Galaxies: A Far-IR Survey with Herschel (KINGFISH) sample. We model the far-IR/submillimeter spectral energy distribution (SED) using images from Spitzer Space Telescope and Herschel Space Observatory. We calculate the cold dust temperature (T(cold)) and emissivity (beta) on a pixel by pixel basis (where each pixel ranges from 0.1-3 kpc^2) using a two temperature modified blackbody fitting routine. Our fitting method allows us to investigate the resolved nature of temperature and emissivity variations by modeling from the galaxy centers to the outskirts (physical scales of ~15-50 kpc, depending on the size of the galaxy). We fit each SED in two ways: (1) fit T(cold) and beta simultaneously, (2) hold beta constant and fit T(cold). We compare T(cold) and beta with star formation rates (calculated from L(Halpha) and L(24)), the luminosity of the old stellar population (traced through L(3.6), and ...

  18. Heterotaxy in Caenorhabditis: widespread natural variation in left-right arrangement of the major organs.

    Science.gov (United States)

    Alcorn, Melissa R; Callander, Davon C; López-Santos, Agustín; Torres Cleuren, Yamila N; Birsoy, Bilge; Joshi, Pradeep M; Santure, Anna W; Rothman, Joel H

    2016-12-19

    Although the arrangement of internal organs in most metazoans is profoundly left-right (L/R) asymmetric with a predominant handedness, rare individuals show full (mirror-symmetric) or partial (heterotaxy) reversals. While the nematode Caenorhabditis elegans is known for its highly determinate development, including stereotyped L/R organ handedness, we found that L/R asymmetry of the major organs, the gut and gonad, varies among natural isolates of the species in both males and hermaphrodites. In hermaphrodites, heterotaxy can involve one or both bilaterally asymmetric gonad arms. Male heterotaxy is probably not attributable to relaxed selection in this hermaphroditic species, as it is also seen in gonochoristic Caenorhabditis species. Heterotaxy increases in many isolates at elevated temperature, with one showing a pregastrulation temperature-sensitive period, suggesting a very early embryonic or germline effect on this much later developmental outcome. A genome-wide association study of 100 isolates showed that male heterotaxy is associated with three genomic regions. Analysis of recombinant inbred lines suggests that a small number of loci are responsible for the observed variation. These findings reveal that heterotaxy is a widely varying quantitative trait in an animal with an otherwise highly stereotyped anatomy, demonstrating unexpected plasticity in an L/R arrangement of the major organs even in a simple animal.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.

  19. Heterotaxy in Caenorhabditis: widespread natural variation in left–right arrangement of the major organs

    Science.gov (United States)

    Callander, Davon C.; López-Santos, Agustín; Torres Cleuren, Yamila N.; Santure, Anna W.

    2016-01-01

    Although the arrangement of internal organs in most metazoans is profoundly left–right (L/R) asymmetric with a predominant handedness, rare individuals show full (mirror-symmetric) or partial (heterotaxy) reversals. While the nematode Caenorhabditis elegans is known for its highly determinate development, including stereotyped L/R organ handedness, we found that L/R asymmetry of the major organs, the gut and gonad, varies among natural isolates of the species in both males and hermaphrodites. In hermaphrodites, heterotaxy can involve one or both bilaterally asymmetric gonad arms. Male heterotaxy is probably not attributable to relaxed selection in this hermaphroditic species, as it is also seen in gonochoristic Caenorhabditis species. Heterotaxy increases in many isolates at elevated temperature, with one showing a pregastrulation temperature-sensitive period, suggesting a very early embryonic or germline effect on this much later developmental outcome. A genome-wide association study of 100 isolates showed that male heterotaxy is associated with three genomic regions. Analysis of recombinant inbred lines suggests that a small number of loci are responsible for the observed variation. These findings reveal that heterotaxy is a widely varying quantitative trait in an animal with an otherwise highly stereotyped anatomy, demonstrating unexpected plasticity in an L/R arrangement of the major organs even in a simple animal. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’. PMID:27821534

  20. Multigenic natural variation underlies Caenorhabditis elegans olfactory preference for the bacterial pathogen Serratia marcescens.

    Science.gov (United States)

    Glater, Elizabeth E; Rockman, Matthew V; Bargmann, Cornelia I

    2014-02-19

    The nematode Caenorhabditis elegans can use olfaction to discriminate among different kinds of bacteria, its major food source. We asked how natural genetic variation contributes to choice behavior, focusing on differences in olfactory preference behavior between two wild-type C. elegans strains. The laboratory strain N2 strongly prefers the odor of Serratia marcescens, a soil bacterium that is pathogenic to C. elegans, to the odor of Escherichia coli, a commonly used laboratory food source. The divergent Hawaiian strain CB4856 has a weaker attraction to Serratia than the N2 strain, and this behavioral difference has a complex genetic basis. At least three quantitative trait loci (QTLs) from the CB4856 Hawaii strain (HW) with large effect sizes lead to reduced Serratia preference when introgressed into an N2 genetic background. These loci interact and have epistatic interactions with at least two antagonistic QTLs from HW that increase Serratia preference. The complex genetic architecture of this C. elegans trait is reminiscent of the architecture of mammalian metabolic and behavioral traits.

  1. Natural variation in gestational cortisol is associated with patterns of growth in marmoset monkeys (Callithrix geoffroyi).

    Science.gov (United States)

    Mustoe, Aaryn C; Birnie, Andrew K; Korgan, Austin C; Santo, Jonathan B; French, Jeffrey A

    2012-02-01

    High levels of prenatal cortisol have been previously reported to retard fetal growth. Although cortisol plays a pivotal role in prenatal maturation, heightened exposure to cortisol can result in lower body weights at birth, which have been shown to be associated with adult diseases like hypertension and cardiovascular disease. This study examines the relationship between natural variation in gestational cortisol and fetal and postnatal growth in marmoset monkeys. Urinary samples obtained during the mother's gestation were analyzed for cortisol. Marmoset body mass index (BMI) was measured from birth through 540 days in 30- or 60-day intervals. Multi-level modeling was used to test if marmoset growth over time was predicted by changes in gestational cortisol controlling for time, sex, litter, and litter size. The results show that offspring exposed to intra-uterine environments with elevated levels of cortisol had lower linear BMI rates of change shortly after birth than did offspring exposed to lower levels of cortisol, but exhibited a higher curvilinear growth rate during adolescence. Average daily change in gestational cortisol during the first trimester had a stronger relationship with postnatal growth than change during the third trimester. Higher exposure to cortisol during gestation does alter developmental trajectories, however there appears to be a catch-up period during later post-natal growth. These observations contribute to a larger discussion about the relationship of maternal glucocorticoids on offspring development and the possibility of an earlier vulnerable developmental window.

  2. Spinal Cord Injury Caused by Stab Wounds: Incidence, Natural History, and Relevance for Future Research.

    Science.gov (United States)

    McCaughey, Euan J; Purcell, Mariel; Barnett, Susan C; Allan, David B

    2016-08-01

    Spinal cord injury caused by stab wounds (SCISW) results from a partial or complete transection of the cord, and presents opportunities for interventional research. It is recognized that there is low incidence, but little is known about the natural history or the patient's suitability for long-term clinical outcome studies. This study aims to provide population-based evidence of the demographics of SCISW, and highlight the issues regarding the potential for future research. The database of the Queen Elizabeth National Spinal Injuries Unit (QENSIU), the sole center for treating SCI in Scotland, was reviewed between 1994 and 2013 to ascertain the incidence, demographics, functional recovery, and mortality rates for new SCISW. During this 20 year period, 35 patients with SCISW were admitted (97.1% male, mean age 30.0 years); 31.4% had a cervical injury, 60.0% had a thoracic injury, and 8.6% had a lumbar injury. All had a neurological examination, with 42.9% diagnosed as motor complete on admission and 77.1% discharged as motor incomplete. A total of 70.4% of patients with an American Spinal Injury Association Impairment Scale (AIS) level of A to C on admission had an improved AIS level on discharge. Nine (25.7%) patients have died since discharge, with mean life expectancy for these patients being 9.1 years after injury (20-65 years of age). Patients had higher levels of comorbidities, substance abuse, secondary events, and poor compliance compared with the general SCI population, which may have contributed to the high mortality rate observed post-discharge. The low incidence, heterogeneous nature, spontaneous recovery rate, and problematic follow-up makes those with penetrating stab injuries of the spinal cord a challenging patient group for SCI research.

  3. Natural variation in Vif: differential impact on APOBEC3G/3F and a potential role in HIV-1 diversification.

    Directory of Open Access Journals (Sweden)

    Viviana Simon

    2005-09-01

    Full Text Available The HIV-1 Vif protein counteracts the antiviral activity exhibited by the host cytidine deaminases APOBEC3G and APOBEC3F. Here, we show that defective vif alleles can readily be found in HIV-1 isolates and infected patients. Single residue changes in the Vif protein sequence are sufficient to cause the loss of Vif-induced APOBEC3 neutralization. Interestingly, not all the detected defects lead to a complete inactivation of Vif function since some mutants retained selective neutralizing activity against APOBEC3F but not APOBEC3G or vice versa. Concordantly, independently hypermutated proviruses with distinguishable patterns of G-to-A substitution attributable to cytidine deamination induced by APOBEC3G, APOBEC3F, or both enzymes were present in individuals carrying proviruses with completely or partly defective Vif variants. Natural variation in Vif function may result in selective and partial neutralization of cytidine deaminases and thereby promote viral sequence diversification within HIV-1 infected individuals.

  4. Natural Variation in Vif: Differential Impact on APOBEC3G/3F and a Potential Role in HIV-1 Diversification.

    Directory of Open Access Journals (Sweden)

    2005-09-01

    Full Text Available The HIV-1 Vif protein counteracts the antiviral activity exhibited by the host cytidine deaminases APOBEC3G and APOBEC3F. Here, we show that defective vif alleles can readily be found in HIV-1 isolates and infected patients. Single residue changes in the Vif protein sequence are sufficient to cause the loss of Vif-induced APOBEC3 neutralization. Interestingly, not all the detected defects lead to a complete inactivation of Vif function since some mutants retained selective neutralizing activity against APOBEC3F but not APOBEC3G or vice versa. Concordantly, independently hypermutated proviruses with distinguishable patterns of G-to-A substitution attributable to cytidine deamination induced by APOBEC3G, APOBEC3F, or both enzymes were present in individuals carrying proviruses with completely or partly defective Vif variants. Natural variation in Vif function may result in selective and partial neutralization of cytidine deaminases and thereby promote viral sequence diversification within HIV-1 infected individuals.

  5. Common TLR1 genetic variation is not associated with death from melioidosis, a common cause of sepsis in rural Thailand.

    Directory of Open Access Journals (Sweden)

    Narisara Chantratita

    Full Text Available Melioidosis, infection caused by the Gram-negative bacterium Burkholderia pseudomallei, is a common cause of sepsis in northeast Thailand. In white North Americans, common functional genetic variation in TLR1 is associated with organ failure and death from sepsis. We hypothesized that TLR1 variants would be associated with outcomes in Thais with melioidosis. We collated the global frequencies of three TLR1 variants that are common in white North American populations: rs5743551 (-7202A/G, rs4833095 (742A/G, and rs5743618 (1804G/T. We noted a reversal of the minor allele from white North American subjects to Asian populations that was particularly pronounced for rs5743618. In the Utah residents of European ancestry, the frequency of the rs5743618 T allele was 17% whereas in Vietnamese subjects the frequency was >99%. We conducted a genetic association study in 427 patients with melioidosis to determine the association of TLR1 variation with organ failure or death. We genotyped rs5743551 and rs4833095. The variants were in high linkage disequilibrium but neither variant was associated with organ failure or in-hospital death. In 300 healthy Thai individuals we further tested the association of TLR1 variation with ex vivo blood responses to Pam3CSK4, a TLR1 agonist. Neither variant was robustly associated with blood cytokine responses induced by Pam3CSK4. We identified additional common variation in TLR1 by searching public databases and the published literature and screened three additional TLR1 variants for associations with Pam3CSK4-induced responses but found none. We conclude that the genetic architecture of TLR1 variation differs substantially in southeast Asians compared to other populations and common variation in TLR1 in Thais is not associated with outcome from melioidosis or with altered blood responses to Pam3CSK4. Our findings highlight the need for additional studies of TLR1 and other innate immune genetic modulators of the inflammatory

  6. The Statistical Significance Test of Regional Climate Change Caused by Land Use and Land Cover Variation in West China

    Institute of Scientific and Technical Information of China (English)

    WANG Hanjie; SHI Weilai; CHEN Xiaohong

    2006-01-01

    The West Development Policy being implemented in China is causing significant land use and land cover (LULC) changes in West China. With the up-to-date satellite database of the Global Land Cover Characteristics Database (GLCCD) that characterizes the lower boundary conditions, the regional climate model RIEMS-TEA is used to simulate possible impacts of the significant LULC variation. The model was run for five continuous three-month periods from 1 June to 1 September of 1993, 1994, 1995, 1996, and 1997, and the results of the five groups are examined by means of a student t-test to identify the statistical significance of regional climate variation. The main results are: (1) The regional climate is affected by the LULC variation because the equilibrium of water and heat transfer in the air-vegetation interface is changed. (2) The integrated impact of the LULC variation on regional climate is not only limited to West China where the LULC varies, but also to some areas in the model domain where the LULC does not vary at all. (3) The East Asian monsoon system and its vertical structure are adjusted by the large scale LULC variation in western China, where the consequences are the enhancement of the westward water vapor transfer from the east oast and the relevant increase of wet-hydrostatic energy in the middle-upper atmospheric layers. (4) The ecological engineering in West China affects significantly the regional climate in Northwest China, North China and the middle-lower reaches of the Yangtze River; there are obvious effects in South, Northeast, and Southwest China, but minor effects in Tibet.

  7. Variation in reference crop evapotranspiration caused by the Ångström-Prescott coefficient

    DEFF Research Database (Denmark)

    Liu, Xiaoying; Mei, Xurong; Li, Yuzhong;

    2009-01-01

    the difference in ET0 between the FAO recommended and the locally calibrated. We found that the direct use of the FAO recommended coefficients significantly affected the estimation of ET0 at most sites, which differed from -3% to 15% at daily scale and from -4% to 16% at monthly scale from the locally calibrated...... ones. These differences are comparable with or larger than those caused by some alternatives of the FAO recommended algorithms for net irradiance or vapor pressure, which further highlights the importance of using the locally calibrated coefficients. The degree of difference in ET0 showed a significant...... of the FAO coefficients, especially in those high yield production areas with altitude

  8. Mutations in MAPT gene cause chromosome instability and introduce copy number variations widely in the genome.

    Science.gov (United States)

    Rossi, Giacomina; Conconi, Donatella; Panzeri, Elena; Redaelli, Serena; Piccoli, Elena; Paoletta, Laura; Dalprà, Leda; Tagliavini, Fabrizio

    2013-01-01

    In addition to the main function of promoting polymerization and stabilization of microtubules, other roles are being attributed to tau, now considered a multifunctional protein. In particular, previous studies suggest that tau is involved in chromosome stability and genome protection. We performed cytogenetic analysis, including molecular karyotyping, on lymphocytes and fibroblasts from patients affected by frontotemporal lobar degeneration carrying different mutations in the microtubule-associated protein tau gene, to investigate the effects of these mutations on genome stability. Furthermore, we analyzed the response of mutated lymphoblastoid cell lines to genotoxic agents to evaluate the participation of tau to DNA repair systems. We found a significantly higher level of chromosome aberrations in mutated than in control cells. Mutated lymphocytes showed higher percentages of stable lesions, clonal and total aneuploidy (medians: 2 versus 0, p $\\ll$ 0.01; 1.5 versus 0, p $\\ll$ 0.01; 16.5 versus 0, p $\\ll$ 0.01, respectively). Fibroblasts of patients showed higher percentages of stable lesions, structural aberrations and total aneuploidy (medians: 0 versus 0, p = 0.03; 5.8 versus 0, p = 0.02; 26.5 versus 12.6, p $\\ll$ 0.01, respectively). In addition, the in depth analysis of DNA copy number variations showed a higher tendency to non-allelic homologous recombination in mutated cells. Finally, while our analysis did not support an involvement of tau in DNA repair systems, it revealed its role in stabilization of chromatin. In summary, our findings indicate a role of tau in genome and chromosome stability that can be ascribed to its function as a microtubule-associated protein as well as a protein protecting chromatin integrity through interaction with DNA.

  9. Genetic and environmental causes of variation in gestation length of Jersey crossbred cattle

    Directory of Open Access Journals (Sweden)

    Anshuman Kumar

    2016-04-01

    Full Text Available Aim: The objective of this study was to investigate the effect of genetic and non-genetic factors and estimate the genetic parameter for gestation length (GL of Jersey crossbred cattle. Materials and Methods: The data included the 986 parturition records on Jersey crossbred cattle maintained at the Eastern Regional Station of ICAR-National Dairy Research Institute, Kalyani, West Bengal, India during 36 years (1978-2013. The data were analyzed applying mixed model least square technique considering the fixed effects of genetic group, season of calving, period of calving, parity of animal, birth weight, and sex of calf born from animal. The effect of sire was included as a random effect in the model. Results: The genetic group of animal, season of calving, parity of animal, and birth weight of calf born were found to be a significant source of variation in the GL, whereas the period of calving and sex of calf did not affect this trait. Cows with 62.5% Jersey inheritance had the shortest and longest GLs, respectively. Cows calved in summer and rainy season had shorter GL than those calved in the winter season. Older cows in 4th parity carried calves for longer days than the cows in 1st parity. The increase in calf birth weight significantly (p<0.01 contributed to a linear increase in GL value in this study. The heritability estimate of GL was 0.24±0.08. Conclusion: It can be concluded that selection for lower GL without distressing future growth of calf can be used to reduce calving difficulty, but a very small standard deviation of GL limits the benefit. Moreover, more accurate prediction of calving date will help in better management and health care of pregnant animals.

  10. Morphological variations caused by fixation techniques may lead to taxonomic confusion in Laeonereis (Polychaeta: Nereididae

    Directory of Open Access Journals (Sweden)

    Verônica M. Oliveira

    2010-02-01

    Full Text Available The nereidid polychaete Laeonereis acuta (Treadwell, 1923 is either considered to be a valid species, or a synonym of Laeonereis culveri (Webster, 1879. The species epithet, acuta, refers to the acuminate anterior region of the body followed by a widening that is visible up to the 10th setiger. The relative width of the anterior region of the body, however, has been reported in the taxonomic literature as variable for Laeonereis Hartman, 1945, a genus known from the eastern coast of North America to Patagonia (southern South America. To test whether variations in this character are real, or whether they correspond to an artifact, we analyzed morphological changes associated with different anesthesia and fixation techniques regularly used to prepare specimens of Laeonereis from southern Brazil (formerly reported as L. acuta. Six treatments, including combinations of anesthetics and fixative agents, and a control, were evaluated in groups of 25 adult animals. A simple model II regression analysis on living specimens showed that the growth is approximately isometric. One-way ANOVA was used to compare the treatment effect on the ratio of peristome width: setiger 6 width. This ratio was smaller in non-anesthetized individuals, especially when prepared in formalin and freshwater. When anesthetized with menthol and fixed in formalin with sea water, individuals retained a shape that was closest to their in vivo shape. Consequently, our results suggest that fixation without prior anesthesia is not recommended for morphological and taxonomical studies. Since morphology and morphometrics of the anterior region are consistently influenced by preparation techniques, it is likely that inadequate fixation routines have introduced several errors in the taxonomic and ecological literature of Laeonereis.

  11. Pathogenic variation in isolates of Pseudomonas causing the brown blotch of cultivated mushroom, Agaricus bisporus

    Directory of Open Access Journals (Sweden)

    Mohamed A. Abou-Zeid

    2012-09-01

    Full Text Available Twenty seven bacterial isolates were isolated from superficial brown discolorations on the caps of cultivated Agaricus bisporus. After White Line Assay (WLA and the assist of Biolog computer-identification system, isolates were divided into groups: (I comprised ninteen bacterial isolates that positively responded to a Pseudomonas "reactans" reference strain (NCPPB1311 in WLA and were identified as Pseudomonas tolaasii, (II comprised two isolates which were WLA+ towards the reference strain (JCM21583 of P. tolaasii and were proposed to be P. "reactans". The third group comprised six isolates, two of which weakly responded to the strain of P. tolaasii and were identified as P. gingeri whereas the other four were WLA- and identified as P. fluorescens (three isolates and P. marginalis (one isolate. Isolates of P. tolaasii showed high aggressiveness compared with those of P. "reactans" in pathogenicity tests. Cubes of 1 cm³ of A. bisporus turned brown and decreased in size when were inoculated with 10 µl of P. tolaasii suspension containing 10(8 CFU ml-1, whereas a similar concentration of P. "reactans" caused only light browning. Fifty µl of the same concentration of P. tolaasii isolates gave typical brown blotch symptoms on fresh mushroom sporophores whereas the two P. "reactans" isolates caused superficial light discoloration only after inoculation with 100 µl of the same concentration. Mixture from both bacterial suspensions increased the brown areas formed on the pileus. This is the first pathogenicity report of P. tolasii and P. "reactans" isolated from cultivated A. bisporus in Egypt.

  12. Tourist perceptions of degradation caused by coastal nature-based recreation.

    Science.gov (United States)

    Priskin, Julianna

    2003-08-01

    Tourist perceptions of environmental degradation caused by nature-based tourism activities in a coastal environment were determined in the Central Coast Region of Western Australia. Structured surveys were administered to 702 visitors over two peak seasons. Visitors were required to indicate their perceptions on a Likert-type scale. Activities assessed were swimming, boating, fishing, diving and snorkelling, (wind)surfing, sandboarding, four-wheel driving, (bush)walking, camping, horseriding and sightseeing. Tourists had significantly variable demographic characteristics over two seasons and participated in different activities. However, perception of environmental degradation of individual activities did not vary significantly between seasons, except for fishing, four-wheel driving and sandboarding. The age, origin and level of education of visitors had more effect on perceptions than gender or income group. Participation in an activity affected perceptions only for those who went fishing, sandboarding, four-wheel driving and sightseeing. Visitor perceptions were comparable to 'real' impacts documented in the recreation ecology literature. The results of this research indicate a need for improved visitor education and interpretation facilities.

  13. A mobile tool about causes and distribution of dramatic natural phenomena

    Science.gov (United States)

    Boppidi, Ravikanth Reddy

    Most Research suggests that tablet computers could aid the study of many scientific concepts that are difficult to grasp, such as places, time and statistics. These occur especially in the study of geology, chemistry, biology and so on. Tapping the technology will soon become critical career training for future generations. Teaching through mobile is more interactive and helps students to grasp quickly. In this thesis an interactive mobile tool is developed which explains about the causes and distribution of natural disasters like Earthquakes, Tsunami, Tropical Cyclones, Volcanic Eruptions and Tornadoes. The application shows the places of disasters on an interactive map and it also contains YouTube embedded videos, which explain the disasters visually. The advantage of this tool is, it can be deployed onto major mobile operating systems like Android and IOS. The application's user interface (UI) is made very responsive using D3 JavaScript, JQuery, Java Script, HTML, CSS so that it can adapt to mobiles, tablets, and desktop screens.

  14. Assessment of infrastructure functional damages caused by natural-technological disasters

    Science.gov (United States)

    Massabò, Marco; Trasforini, Eva; Traverso, Stefania; Rudari, Roberto; De Angeli, Silvia; Cecinati, Francesca; Cerruti, Valentina

    2013-04-01

    The assessment of infrastructure damages caused by technological disaster poses several challenges, from gathering needed information on the territorial system to the definition of functionality curves for infrastructures elements (such as, buildings, road school) that are exposed to both natural and technological event. Moreover, areas affected by natural or natech (technological disasters triggered by natural events) disasters have often very large extensions and a rapid survey of them to gather all the needed information is a very difficult task, for many reasons, not least the difficult access to the existing databases and resources. We use multispectral optical imagery with other geographical and unconventional data to identify and characterize exposed elements. Our efforts in the virtual survey and during the investigation steps have different aims: to identify the vulnerability of infrastructures, buildings or activities; to execute calculations of exposition to risk; to estimate physical and functional damages. Subsequently, we apply specific algorithms to estimate values of acting forces and physical and functional damages. The updated picture of target areas in terms of risk-prone people, infrastructures and their connections is very important. It is possible to develop algorithms providing values of systemic functionality for each network element. The methodology is here applied to a natech disaster, arising from the combination of a flood event (specifically, the January 2010 flooding of Drin and Buna rivers, with a worsening in the road safety levels in the Shkoder area) with and the subsequent overturning of a truck transporting hazardous material. The accident causes the loss of containment and the total material release. Once the release has taken place, the evolution will depend on the physical state of the substance spilled (liquid, gas or dust). As a specific case we consider the rupture of a trucks transporting liquid fuels such as gasoline

  15. Genetic variation in plant volatile emission does not result in differential attraction of natural enemies in the field.

    Science.gov (United States)

    Wason, Elizabeth L; Hunter, Mark D

    2014-02-01

    Volatile organic chemical (VOC) emission by plants may serve as an adaptive plant defense by attracting the natural enemies of herbivores. For plant VOC emission to evolve as an adaptive defense, plants must show genetic variability for the trait. To date, such variability has been investigated primarily in agricultural systems, yet relatively little is known about genetic variation in VOCs emitted by natural populations of native plants. Here, we investigate intraspecific variation in constitutive and herbivore-induced plant VOC emission using the native common milkweed plant (Asclepias syriaca) and its monarch caterpillar herbivore (Danaus plexippus) in complementary field and common garden greenhouse experiments. In addition, we used a common garden field experiment to gauge natural enemy attraction to milkweed VOCs induced by monarch damage. We found evidence of genetic variation in the total constitutive and induced concentrations of VOCs and the composition of VOC blends emitted by milkweed plants. However, all milkweed genotypes responded similarly to induction by monarchs in terms of their relative change in VOC concentration and blend. Natural enemies attacked decoy caterpillars more frequently on damaged than on undamaged milkweed, and natural enemy visitation was associated with higher total VOC concentrations and with VOC blend. Thus, we present evidence that induced VOCs emitted by milkweed may function as a defense against herbivores. However, plant genotypes were equally attractive to natural enemies. Although milkweed genotypes diverge phenotypically in their VOC concentrations and blends, they converge into similar phenotypes with regard to magnitude of induction and enemy attraction.

  16. Human-specific HERV-K insertion causes genomic variations in the human genome.

    Directory of Open Access Journals (Sweden)

    Wonseok Shin

    Full Text Available Human endogenous retroviruses (HERV sequences account for about 8% of the human genome. Through comparative genomics and literature mining, we identified a total of 29 human-specific HERV-K insertions. We characterized them focusing on their structure and flanking sequence. The results showed that four of the human-specific HERV-K insertions deleted human genomic sequences via non-classical insertion mechanisms. Interestingly, two of the human-specific HERV-K insertion loci contained two HERV-K internals and three LTR elements, a pattern which could be explained by LTR-LTR ectopic recombination or template switching. In addition, we conducted a polymorphic test and observed that twelve out of the 29 elements are polymorphic in the human population. In conclusion, human-specific HERV-K elements have inserted into human genome since the divergence of human and chimpanzee, causing human genomic changes. Thus, we believe that human-specific HERV-K activity has contributed to the genomic divergence between humans and chimpanzees, as well as within the human population.

  17. Variation in, and causes of, toxicity of cigarette butts to a cladoceran and microtox.

    Science.gov (United States)

    Micevska, T; Warne, M St J; Pablo, F; Patra, R

    2006-02-01

    Cigarette butts are the most numerically frequent form of litter in the world. In Australia alone, 24-32 billion cigarette butts are littered annually. Despite this littering, few studies have been undertaken to explore the toxicity of cigarette butts in aquatic ecosystems. The acute toxicity of 19 filtered cigarette types to Ceriodaphnia cf. dubia (48-hr EC50 (immobilization)) and Vibrio fischeri (30-min EC50 (bioluminescence)) was determined using leachates from artificially smoked cigarette butts. There was a 2.9- and 8-fold difference in toxicity between the least and most toxic cigarette butts to C. cf. dubia and V. fischeri, respectively. Overall, C. cf. dubia was more inherently sensitive than V. fischeri by a factor of approximately 15.4, and the interspecies relationship between C. cf. dubia and V. fischeri was poor (R(2) = 0.07). This poor relationship indicates that toxicity data for cigarette butts for one species could not predict or model the toxicity of cigarette butts to the other species. However, the order of the toxicity of leachates can be predicted. It was determined that organic compounds caused the majority of toxicity in the cigarette butt leachates. Of the 14 organic compounds identified, nicotine and ethylphenol were suspected to be the main causative toxicants. There was a strong relationship between toxicity and tar content and between toxicity and nicotine content for two of the three brands of cigarettes (R(2 )> 0.70) for C. cf. dubia and one brand for V. fischeri. However, when the cigarettes were pooled, the relationship was weak (R(2) < 0.40) for both test species. Brand affected the toxicity to both species but more so for V. fischeri.

  18. The genetics of phytate and phosphate accumulation in seeds and leaves of Arabidopsis thaliana, using natural variation

    NARCIS (Netherlands)

    Bentsink, L.; Yuan, K.; Koornneef, M.; Vreugdenhil, D.

    2003-01-01

    Phytate (myo-inositol-1,2,3,4,5,6-hexakisphosphate, InsP6) is the most abundant P-containing compound in plants, and an important anti-nutritional factor, due to its ability to complex essential micro-nutrients, e.g. iron and zinc. Analysis of natural variation for InsP6 and Pi accumulation in seeds

  19. Natural Variation of Leaf Thickness and Its Association to Yield Traits in indica Rice

    Institute of Scientific and Technical Information of China (English)

    LIU Chuan-guang; ZHOU Xin-qiao; CHEN Da-gang; LI Li-jun; LI Ju-chang; CHEN You-ding

    2014-01-01

    Leaf thickness is an important morphological trait in rice. Its association to the yield potential, as of now has not been documented because of the shortage of the equipment which could conveniently measure the leaf thickness in rice. In this study, the thickness of top three leaves of 208 cultivars had been determined by a nondestructive rice leaf thickness instrument for the research of the natural variation of leaves thickness and its association to yield traits inindica rice. The results showed that the lfag leaf was the thickest, and the 2nd leaf was thicker than the 3rd leaf. Analysis of variance indicated the existence of wide genetic diversity of leaf thickness among the investigatedindica rice genotypes. The tight correlation among the thicknesses of the top three leaves means that the leaf thickness traits share one genetic control system. Leaf thickness had a signiifcant positive correlation with leaf length and a positive correlation with leaf width, indicated that thicker leaf was beneifcial to increasing the single leaf area. The results of correlation analysis revealed that thicker leaf should be proiftable to the leaf erection, higher numbers of grains per panicle and higher grains weight per panicle. However, the signiifcantly negative correlation between leaf thickness and number of panicles per plant counteracted the proiftability from increased grains weight per panicle, so that the correlations of the thicknesses of the top three leaves to yield and biomass were positive but not signiifcantly. It has made great progress in the genetic improvement of leaves thickness in inbredindica rice breeding in Guangdong Province, China, since the 1990s.

  20. Toward Understanding The B[e] Phenomenon. VI. Nature and Spectral Variations of HD 85567.

    Science.gov (United States)

    Khokhlov, S. A.; Miroshnichenko, A. S.; Mennickent, R.; Cabezas, M.; Zhanabaev, Z. Zh.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; Nysewander, M. C.; LaCluyze, A. P.

    2017-01-01

    We report the results of high-resolution (R ∼ 80,000) spectroscopic observations of the emission-line object HD 85567, which has been classified as an FS CMa type object or a pre-main-sequence star. The main goal is to put more constraints on the object’s fundamental parameters, as well as on its nature and evolutionary state. Absorption lines in the spectrum of HD 85567 were found to be similar to those of mid-B-type dwarfs and correspond to the following fundamental parameters: Teff = 15,000 ± 500 K, v\\sin i=31+/- 3 km s‑1, and {log} g∼ 4.0. The interstellar extinction, AV = 0.50 ± 0.02 mag, was measured using the strengths of some diffuse interstellar bands. We also obtained UBV(RI)c images of a 10‧ × 10‧ region around the object. Photometry of projectionally close stars was used to derive an interstellar extinction law in this direction and resulted in a distance of 1300 ± 100 pc to the object and a luminosity of log L/L⊙ = 3.3 ± 0.2. We found no significant radial velocity variations of the absorption lines in the spectra of HD 85567 obtained during two-month-long periods of time in 2012 and 2015. Our analysis of the spectroscopic and photometric data available for the star led us to a conclusion that it cannot be a pre-main-sequence Herbig Ae/Be star. We argue that the circumstellar gas and dust were produced during the object’s evolution as most likely a binary system, which contains an undetected secondary component and is unlikely to be a merger product. This paper is partly based on observations obtained at the 1.5 m telescope of the Cerro Tololo Interamerican Observatory under CNTAC proposal 2012A–016.

  1. Naturally occurring variation in trophoblast invasion as a source of novel (epigenetic biomarkers

    Directory of Open Access Journals (Sweden)

    Marie eVan DIjk

    2012-02-01

    Full Text Available During the first trimester of pregnancy fetal trophoblasts invade the maternal decidua, thereby remodelling the maternal spiral arteries. This process of trophoblast invasion is very similar to cancer cell invasion, with multiple signaling pathways shared between the two. Pregnancy-related diseases, e.g. pre-eclampsia, and cancer metastasis start with a decrease or increase in cellular invasion, respectively. Here, we investigate if first trimester placental explants can be used to identify epigenetic factors associated with changes in cellular invasion and their potential use as biomarkers. We show that the outgrowth potential of first trimester explants significantly correlates with promoter methylation of PRKCDBP and MMP2, two genes known to be differentially methylated in both placenta and cancer. The increase in methylation percentage coincides with an increase in invasion potential. Subsequently, as a non-invasive marker must be detectable in blood, plasma samples of pregnant and non-pregnant women were analyzed. The MMP2 promoter showed high methylation levels in non-pregnant plasma samples, which decreased in pregnant plasma. The decrease in methylated plasma DNA during pregnancy is most likely due to the fractional increase in unmethylated placental DNA. This suggests that the level of unmethylated DNA has the potential to be used as an invasion marker, where higher levels of unmethylated DNA indicate a lower invasion potential of trophoblasts.These proof of principle data provide evidence that human first trimester placental explants are an excellent ex vivo model system to identify (epigenetic factors and thus potential biomarkers associated with changes in cellular invasion, e.g. to detect pregnancy-related diseases or cancer metastasis. To identify novel biomarkers the next step is to correlate naturally occurring variation in invasion potential to changes in (epigenetic factors by genome-wide approaches such as massively parallel

  2. Natural variations of copper and sulfur stable isotopes in blood of hepatocellular carcinoma patients.

    Science.gov (United States)

    Balter, Vincent; Nogueira da Costa, Andre; Bondanese, Victor Paky; Jaouen, Klervia; Lamboux, Aline; Sangrajrang, Suleeporn; Vincent, Nicolas; Fourel, François; Télouk, Philippe; Gigou, Michelle; Lécuyer, Christophe; Srivatanakul, Petcharin; Bréchot, Christian; Albarède, Francis; Hainaut, Pierre

    2015-01-27

    The widespread hypoxic conditions of the tumor microenvironment can impair the metabolism of bioessential elements such as copper and sulfur, notably by changing their redox state and, as a consequence, their ability to bind specific molecules. Because competing redox state is known to drive isotopic fractionation, we have used here the stable isotope compositions of copper ((65)Cu/(63)Cu) and sulfur ((34)S/(32)S) in the blood of patients with hepatocellular carcinoma (HCC) as a tool to explore the cancer-driven copper and sulfur imbalances. We report that copper is (63)Cu-enriched by ∼0.4‰ and sulfur is (32)S-enriched by ∼1.5‰ in the blood of patients compared with that of control subjects. As expected, HCC patients have more copper in red blood cells and serum compared with control subjects. However, the isotopic signature of this blood extra copper burden is not in favor of a dietary origin but rather suggests a reallocation in the body of copper bound to cysteine-rich proteins such as metallothioneins. The magnitude of the sulfur isotope effect is similar in red blood cells and serum of HCC patients, implying that sulfur fractionation is systemic. The (32)S-enrichment of sulfur in the blood of HCC patients is compatible with the notion that sulfur partly originates from tumor-derived sulfides. The measurement of natural variations of stable isotope compositions, using techniques developed in the field of Earth sciences, can provide new means to detect and quantify cancer metabolic changes and provide insights into underlying mechanisms.

  3. Linking dynamic phenotyping with metabolite analysis to study natural variation in drought responses of Brachypodium distachyon

    Directory of Open Access Journals (Sweden)

    Lorraine H.C. Fisher

    2016-11-01

    Full Text Available Drought is an important environmental stress limiting the productivity of major crops worldwide. Understanding drought tolerance and possible mechanisms for improving drought resistance is therefore a prerequisite to develop drought-tolerant crops that produce significant yields with reduced amounts of water. Brachypodium distachyon (Brachypodium is a key model species for cereals, forage grasses and energy grasses. In this study, initial screening of a Brachypodium germplasm collection consisting of 138 different ecotypes exposed to progressive drought, highlighted the natural variation in morphology, biomass accumulation and responses to drought stress. A core set of ten ecotypes, classified as being either tolerant, susceptible or intermediate, in response to drought stress, were exposed to mild or severe (respectively 15% and 0% soil water content drought stress and phenomic parameters linked to growth and colour changes were assessed. When exposed to severe drought stress, phenotypic data and metabolite profiling combined with multivariate analysis revealed a remarkable consistency in separating the selected ecotypes into their different pre-defined drought tolerance groups. Increases in several metabolites, including for the phytohormones jasmonic acid and salicylic acid, and TCA-cycle intermediates, were positively correlated with biomass yield and with reduced yellow pixel counts; suggestive of delayed senescence, both key target traits for crop improvement to drought stress. While metabolite analysis also separated ecotypes into the distinct tolerance groupings after exposure to mild drought stress, similar analysis of the phenotypic data failed to do so, confirming the value of metabolomics to investigate early responses to drought stress. The results highlight the potential of combining the analyses of phenotypic and metabolic responses to identify key mechanisms and markers associated with drought tolerance in both the Brachypodium

  4. Natural variations of copper and sulfur stable isotopes in blood of hepatocellular carcinoma patients

    Science.gov (United States)

    Balter, Vincent; Nogueira da Costa, Andre; Paky Bondanese, Victor; Jaouen, Klervia; Lamboux, Aline; Sangrajrang, Suleeporn; Vincent, Nicolas; Fourel, François; Télouk, Philippe; Gigou, Michelle; Lécuyer, Christophe; Srivatanakul, Petcharin; Bréchot, Christian; Albarède, Francis; Hainaut, Pierre

    2015-01-01

    The widespread hypoxic conditions of the tumor microenvironment can impair the metabolism of bioessential elements such as copper and sulfur, notably by changing their redox state and, as a consequence, their ability to bind specific molecules. Because competing redox state is known to drive isotopic fractionation, we have used here the stable isotope compositions of copper (65Cu/63Cu) and sulfur (34S/32S) in the blood of patients with hepatocellular carcinoma (HCC) as a tool to explore the cancer-driven copper and sulfur imbalances. We report that copper is 63Cu-enriched by ∼0.4‰ and sulfur is 32S-enriched by ∼1.5‰ in the blood of patients compared with that of control subjects. As expected, HCC patients have more copper in red blood cells and serum compared with control subjects. However, the isotopic signature of this blood extra copper burden is not in favor of a dietary origin but rather suggests a reallocation in the body of copper bound to cysteine-rich proteins such as metallothioneins. The magnitude of the sulfur isotope effect is similar in red blood cells and serum of HCC patients, implying that sulfur fractionation is systemic. The 32S-enrichment of sulfur in the blood of HCC patients is compatible with the notion that sulfur partly originates from tumor-derived sulfides. The measurement of natural variations of stable isotope compositions, using techniques developed in the field of Earth sciences, can provide new means to detect and quantify cancer metabolic changes and provide insights into underlying mechanisms.

  5. Natural variation of the RICE FLOWERING LOCUS T 1 contributes to flowering time divergence in rice.

    Directory of Open Access Journals (Sweden)

    Eri Ogiso-Tanaka

    Full Text Available In rice (Oryza sativa L., there is a diversity in flowering time that is strictly genetically regulated. Some indica cultivars show extremely late flowering under long-day conditions, but little is known about the gene(s involved. Here, we demonstrate that functional defects in the florigen gene RFT1 are the main cause of late flowering in an indica cultivar, Nona Bokra. Mapping and complementation studies revealed that sequence polymorphisms in the RFT1 regulatory and coding regions are likely to cause late flowering under long-day conditions. We detected polymorphisms in the promoter region that lead to reduced expression levels of RFT1. We also identified an amino acid substitution (E105K that leads to a functional defect in Nona Bokra RFT1. Sequencing of the RFT1 region in rice accessions from a global collection showed that the E105K mutation is found only in indica, and indicated a strong association between the RFT1 haplotype and extremely late flowering in a functional Hd1 background. Furthermore, SNPs in the regulatory region of RFT1 and the E105K substitution in 1,397 accessions show strong linkage disequilibrium with a flowering time-associated SNP. Although the defective E105K allele of RFT1 (but not of another florigen gene, Hd3a is found in many cultivars, relative rate tests revealed no evidence for differential rate of evolution of these genes. The ratios of nonsynonymous to synonymous substitutions suggest that the E105K mutation resulting in the defect in RFT1 occurred relatively recently. These findings indicate that natural mutations in RFT1 provide flowering time divergence under long-day conditions.

  6. Natural variation in rosette size under salt stress conditions corresponds to developmental differences between Arabidopsis accessions and allelic variation in the LRR-KISS gene

    KAUST Repository

    Julkowska, Magdalena M.

    2016-02-11

    Natural variation among Arabidopsis accessions is an important genetic resource to identify mechanisms underlying plant development and stress tolerance. To evaluate the natural variation in salinity stress tolerance, two large-scale experiments were performed on two populations consisting of 160 Arabidopsis accessions each. Multiple traits, including projected rosette area, and fresh and dry weight were collected as an estimate for salinity tolerance. Our results reveal a correlation between rosette size under salt stress conditions and developmental differences between the accessions grown in control conditions, suggesting that in general larger plants were more salt tolerant. This correlation was less pronounced when plants were grown under severe salt stress conditions. Subsequent genome wide association study (GWAS) revealed associations with novel candidate genes for salinity tolerance such as LRR-KISS (At4g08850), flowering locus KH-domain containing protein and a DUF1639-containing protein. Accessions with high LRR-KISS expression developed larger rosettes under salt stress conditions. Further characterization of allelic variation in candidate genes identified in this study will provide more insight into mechanisms of salt stress tolerance due to enhanced shoot growth.

  7. The chicken as a natural model for extraintestinal infections caused by avian pathogenic Escherichia coli (APEC).

    Science.gov (United States)

    Antão, Esther-Maria; Glodde, Susanne; Li, Ganwu; Sharifi, Reza; Homeier, Timo; Laturnus, Claudia; Diehl, Ines; Bethe, Astrid; Philipp, Hans-C; Preisinger, Rudolf; Wieler, Lothar H; Ewers, Christa

    2008-01-01

    E. coli infections in avian species have become an economic threat to the poultry industry worldwide. Several factors have been associated with the virulence of E. coli in avian hosts, but no specific virulence gene has been identified as being entirely responsible for the pathogenicity of avian pathogenic E. coli (APEC). Needless to say, the chicken would serve as the best model organism for unravelling the pathogenic mechanisms of APEC, an extraintestinal pathogen. Five-week-old white leghorn SPF chickens were infected intra-tracheally with a well characterized APEC field strain IMT5155 (O2:K1:H5) using different doses corresponding to the respective models of infection established, that is, the lung colonization model allowing re-isolation of bacteria only from the lung but not from other internal organs, and the systemic infection model. These two models represent the crucial steps in the pathogenesis of APEC infections, including the colonization of the lung epithelium and the spread of bacteria throughout the bloodstream. The read-out system includes a clinical score, pathomorphological changes and bacterial load determination. The lung colonization model has been established and described for the first time in this study, in addition to a comprehensive account of a systemic infection model which enables the study of severe extraintestinal pathogenic E. coli (ExPEC) infections. These in vivo models enable the application of various molecular approaches to study host-pathogen interactions more closely. The most important application of such genetic manipulation techniques is the identification of genes required for extraintestinal virulence, as well as host genes involved in immunity in vivo. The knowledge obtained from these studies serves the dual purpose of shedding light on the nature of virulence itself, as well as providing a route for rational attenuation of the pathogen for vaccine construction, a measure by which extraintestinal infections, including

  8. Novel approach for evaluation of air change rate in naturally ventilated occupied spaces based on metabolic CO2 time variation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Markov, Detelin G.

    2014-01-01

    , air-tight space, constant indoor pressure and temperature. The proposed approach for ACR evaluation can be applied to time intervals with any length, even with varying parameters of both indoor and outdoor air, in which metabolic CO2 generation rate is known and constant. This approach makes possible......IAQ in many residential buildings relies on non-organized natural ventilation. Accurate evaluation of air change rate (ACR) in this situation is difficult due to the nature of the phenomenon - intermittent infiltration-exfiltration periods of mass exchange between the room air and the outdoor air...... at low rate. This paper describes a new approach for ACR evaluation in naturally ventilated occupied spaces. Actual metabolic CO2 time variation record in an interval of time is compared with the computed variation of metabolic CO2 for the same time interval under reference conditions: sleeping occupants...

  9. A man-induced landslide in Lower Austria: natural conditions versus man-made causes

    Science.gov (United States)

    Kittel, Roland; Ottner, Franz; Damm, Bodo; Terhorst, Birgit

    2010-05-01

    In many cases, composition and characteristics of hillslope sediments are of particular importance related to landslide research in low mountain areas. The interaction of geologic, geomorphologic, and hydrologic factors determines the susceptibility for mass movements, which is affected by human impact as well. The present study aims to investigate factors that control mass movements and natural and anthropogenic impacts. On March 8th 2009, a landslide of 30.000 to 50.000 m³ occurred that destroyed a large part of a sports ground in the village of Hintersdorf, municipality of St. Andrä-Wördern (Lower Austria). As a result of extensive water supply ground liquefaction was initiated and the slide mass moved in form of a mud flow about 200 m down slope. As a consequence a small forest area and a fishpond were destroyed and an adjacent road was damaged. Closely to the event, first studies started and showed that the Hintersdorf landslide was triggered by extensive water saturation combined with hydrostatic pressure inside the slide mass. Heavy and long-lasting rainfalls and the start of snowmelt caused strong seepage and soil water saturation. Furthermore, insufficient ground drainage and overflow of a small retention pond intensified the unfavourable impact on soil-mechanical stability. Further studies included archive data analyse, field survey, as well as laboratory analyse and showed that high landslide susceptibility at the Hintersdorf landslide site was caused by a bundle of factors that control the process: The sports ground was built nearby the head of a trough valley that collects interflow and surface run-off from the surrounding slopes. The Flysch bedrock is covered extensively by clayey slope deposits. Furthermore, in the area of the valley head a waste deposit was operated up to the 1980's that resulted in a thick waste filling there. The Hintersdorf sports ground was constructed in 1984 on top of the waste body. Preliminary results show that hillslope

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

    NARCIS (Netherlands)

    Cook, D.C.; Zdraljevic, S.; Tanny, R.E.; Seo, B.; Riccardi, D.D.; Noble, L.M.; Rockman, M.V.; Alkema, M.J.; Braendle, C.; Kammenga, J.E.; Wang, J.; Kruglyak, L.; Felix, M.A.; Lee, J.; Andersen, E.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 organis

  11. Regulatory change at Physalis Organ Size 1 correlates to natural variation in tomatillo reproductive organ size.

    Science.gov (United States)

    Wang, Li; He, Lingli; Li, Jing; Zhao, Jing; Li, Zhichao; He, Chaoying

    2014-07-01

    The genetic basis of size variation in the reproductive organs of tomatillo (Physalis philadelphica) is unknown. Here we report that the expression levels of the gene Physalis Organ Size 1 (POS1) are positively associated with size variation in P. philadelphica reproductive organs such flowers, berries and seeds. POS1 knockdown results in smaller flowers and berries with smaller cells as compared with their wild-type counterparts. Conversely, POS1 overexpression promotes organ size without increasing the cell number. The first introns of the POS1 alleles from the large, intermediate and small tomatillo groups contain one, two and three 37-bp repeats, respectively. Furthermore, our results show that copy variation of repeats in the first intron of POS1 alleles results in differential expression of this gene. Thus, co-variation in tomatillo reproductive organ sizes can be attributed to the novel regulatory variation in POS1.

  12. Genetic architecture of natural variation in cuticular hydrocarbon composition in Drosophila melanogaster.

    Science.gov (United States)

    Dembeck, Lauren M; Böröczky, Katalin; Huang, Wen; Schal, Coby; Anholt, Robert R H; Mackay, Trudy F C

    2015-11-14

    Insect cuticular hydrocarbons (CHCs) prevent desiccation and serve as chemical signals that mediate social interactions. Drosophila melanogaster CHCs have been studied extensively, but the genetic basis for individual variation in CHC composition is largely unknown. We quantified variation in CHC profiles in the D. melanogaster Genetic Reference Panel (DGRP) and identified novel CHCs. We used principal component (PC) analysis to extract PCs that explain the majority of CHC variation and identified polymorphisms in or near 305 and 173 genes in females and males, respectively, associated with variation in these PCs. In addition, 17 DGRP lines contain the functional Desat2 allele characteristic of African and Caribbean D. melanogaster females (more 5,9-C27:2 and less 7,11-C27:2, female sex pheromone isomers). Disruption of expression of 24 candidate genes affected CHC composition in at least one sex. These genes are associated with fatty acid metabolism and represent mechanistic targets for individual variation in CHC composition.

  13. A systems approach to model natural variation in reactive properties of bacterial ribosomes

    Directory of Open Access Journals (Sweden)

    Schmidt Thomas M

    2008-07-01

    Full Text Available Abstract Background Natural variation in protein output from translation in bacteria and archaea may be an organism-specific property of the ribosome. This paper adopts a systems approach to model the protein output as a measure of specific ribosome reactive properties in a ribosome-mediated translation apparatus. We use the steady-state assumption to define a transition state complex for the ribosome, coupled with mRNA, tRNA, amino acids and reaction factors, as a subsystem that allows a focus on the completed translational output as a measure of specific properties of the ribosome. Results In analogy to the steady-state reaction of an enzyme complex, we propose a steady-state translation complex for mRNA from any gene, and derive a maximum specific translation activity, Ta(max, as a property of the ribosomal reaction complex. Ta(max has units of a-protein output per time per a-specific mRNA. A related property of the ribosome, T˜a(max⁡ MathType@MTEF@5@5@+=feaagaart1ev2aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGaciGaaiaabeqaaeqabiWaaaGcbaGafmivaqLbaGaadaWgaaWcbaGaemyyaeMaeiikaGIagiyBa0MaeiyyaeMaeiiEaGNaeiykaKcabeaaaaa@3464@, has units of a-protein per time per total RNA with the relationship T˜a(max⁡ MathType@MTEF@5@5@+=feaagaart1ev2aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGaciGaaiaabeqaaeqabiWaaaGcbaGafmivaqLbaGaadaWgaaWcbaGaemyyaeMaeiikaGIagiyBa0MaeiyyaeMaeiiEaGNaeiykaKcabeaaaaa@3464@ = ρa Ta(max, where ρa represents the fraction of total RNA committed to translation output of Pa from gene a message. Ta(max as a ribosome property is analogous to kcat for a purified enzyme, and T˜a(max⁡ MathType@MTEF@5@5@+=feaagaart1ev2aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9g

  14. Research of Ionospheric Total Electron Content Variations Caused by Powerful Radio Emission of `SURA' Facility on Network of Gnss - Receivers

    Science.gov (United States)

    Kogogin, Denis; Nasyrov, Igor; Grach, Savely; Shindin, Alexey; Zagretdinov, Renat; Shaimukhametov, Ramil; Kislichin, Alexander; Ryabova, Mariya

    Large-scale irregularities with scales of 5-50 km can be effectively studied using dual-frequency raying by signals of the Navstar (GPS) and GLONASS microwave satellite systems. During propagation through the heated region, such signals acquire an additional phase increment stipulated by the dispersion of radio waves in the ionospheric plasma and linearly related to the total electron content (TEC) on the propagation trajectory. In this work we present results of measurement of total electron content (TEC) variations in the F2 part of the ionosphere of the Earth caused by powerful radio emission of “Sura” facility carried out during several experimental companies from 2010 to 2013 years. Parameters of TEC-variations were obtained by dual - frequency global navigation satellite systems (GNSS) diagnostics. Registration of signal parameters from GNSS-transmitters was performed at spatially separated sites around the “Sura” facility: Vasilsursk (56(°) 08' N, 46(°) 05' E), Zelenodolsk (55(°) 52' N, 48(°) 33' E), Kazan (55(°) 48' N, 49(°) 08' E) and Yoshkar-Ola (56(°) 38'N, 47(°) 52'E). The initial data containing measurements of the phase L and pseudorange P for the operating frequencies f1 =1575.42 MHz and f2 = 1227.60 MHz are RINEX files. For a detail study of small TEC variations based on the initial dependence, the trend was removed by subtraction of the moving average with the use of the linear weight function. In the experiments radio path from GNSS satellite to Vasilsursk passed over the disturbed region of ionosphere, but radio paths to Zelenodolsk, to Kazan and to Yoshkar-Ola did not. However, TEC-variations correlated with pumping of ionosphere by ”Sura” facility were detected for three ground measurements sites, situated along the “Sura” facility geomagnetic longitude (Vasilsursk, Zelenodolsk, Kazan). Magnitudes of TEC-variations reached 0.15-0.3 TECU. Velocity of propagation of large-scale ionospheric disturbance stimulated by

  15. Topography caused by mantle density variations: observation-based estimates and models derived from tomography and lithosphere thickness

    Science.gov (United States)

    Steinberger, Bernhard

    2016-04-01

    Large-scale topography may be due to several causes, including (1) variations in crustal thickness and density structure, (2) oceanic lithosphere age differences, (3) subcrustal density variations in the continental lithosphere and (4) convective flow in the mantle beneath the lithosphere. The last contribution in particular may change with time and be responsible for continental inundations; distinguishing between these contributions is therefore important for linking Earth's history to its observed geological record. As a step towards this goal, this paper aims at such distinction for the present-day topography: the approach taken is deriving a `model' topography due to contributions (3) and (4), along with a model geoid, using a geodynamic mantle flow model. Both lithosphere thickness and density anomalies beneath the lithosphere are inferred from seismic tomography. Density anomalies within the continental lithosphere are uncertain, because they are probably due to variations in composition and temperature, making a simple scaling from seismic to density anomalies inappropriate. Therefore, we test a number of different assumptions regarding these. As a reality check, model topography is compared, in terms of both correlation and amplitude ratio, to `residual' topography, which follows from observed topography after subtracting contributions (1) and (2). The model geoid is compared to observations as well. Comparatively good agreement is found if there is either an excess density of ≈0.2 per cent in the lithosphere above ≈150 km depth, with anomalies below as inferred from tomography, or if the excess density is ≈0.4 per cent in the entire lithosphere. Further, a good fit is found for viscosity ≈1020 Pa s in the asthenosphere, increasing to ≈1023 Pa s in the lower mantle above D'. Results are quite dependent on which tomography models they are based on; for some recent ones, topography correlation is ≈0.6, many smaller scale features are matched

  16. Genome-wide association studies identify heavy metal ATPase3 as the primary determinant of natural variation in leaf cadmium in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Dai-Yin Chao

    2012-09-01

    Full Text Available Understanding the mechanism of cadmium (Cd accumulation in plants is important to help reduce its potential toxicity to both plants and humans through dietary and environmental exposure. Here, we report on a study to uncover the genetic basis underlying natural variation in Cd accumulation in a world-wide collection of 349 wild collected Arabidopsis thaliana accessions. We identified a 4-fold variation (0.5-2 µg Cd g(-1 dry weight in leaf Cd accumulation when these accessions were grown in a controlled common garden. By combining genome-wide association mapping, linkage mapping in an experimental F2 population, and transgenic complementation, we reveal that HMA3 is the sole major locus responsible for the variation in leaf Cd accumulation we observe in this diverse population of A. thaliana accessions. Analysis of the predicted amino acid sequence of HMA3 from 149 A. thaliana accessions reveals the existence of 10 major natural protein haplotypes. Association of these haplotypes with leaf Cd accumulation and genetics complementation experiments indicate that 5 of these haplotypes are active and 5 are inactive, and that elevated leaf Cd accumulation is associated with the reduced function of HMA3 caused by a nonsense mutation and polymorphisms that change two specific amino acids.

  17. Natural gas and CO2 price variation: impact on the relative cost-efficiency of LNG and pipelines.

    Science.gov (United States)

    Ulvestad, Marte; Overland, Indra

    2012-06-01

    THIS ARTICLE DEVELOPS A FORMAL MODEL FOR COMPARING THE COST STRUCTURE OF THE TWO MAIN TRANSPORT OPTIONS FOR NATURAL GAS: liquefied natural gas (LNG) and pipelines. In particular, it evaluates how variations in the prices of natural gas and greenhouse gas emissions affect the relative cost-efficiency of these two options. Natural gas is often promoted as the most environmentally friendly of all fossil fuels, and LNG as a modern and efficient way of transporting it. Some research has been carried out into the local environmental impact of LNG facilities, but almost none into aspects related to climate change. This paper concludes that at current price levels for natural gas and CO2 emissions the distance from field to consumer and the volume of natural gas transported are the main determinants of transport costs. The pricing of natural gas and greenhouse emissions influence the relative cost-efficiency of LNG and pipeline transport, but only to a limited degree at current price levels. Because more energy is required for the LNG process (especially for fuelling the liquefaction process) than for pipelines at distances below 9100 km, LNG is more exposed to variability in the price of natural gas and greenhouse gas emissions up to this distance. If the prices of natural gas and/or greenhouse gas emission rise dramatically in the future, this will affect the choice between pipelines and LNG. Such a price increase will be favourable for pipelines relative to LNG.

  18. Spatiotemporal variations in channel changes caused by cumulative factors in a meandering river: The lower Peixe River, Brazil

    Science.gov (United States)

    Morais, Eduardo S.; Rocha, Paulo C.; Hooke, Janet

    2016-11-01

    Channel changes in meandering rivers naturally exhibit complex behaviour, and understanding the river dynamics can be challenging in environments also subject to cumulative human impacts. Planform changes were analysed on four reaches of the lower course of the Peixe River, Brazil, at decadal scales over the period 1962-2008 from aerial photographs and satellite imagery, complemented by a historical map from 1907. Analysis of the spatial and temporal patterns of channel change mechanisms and morphometry of bends and of the sinuosity and morphodynamic variations of the reaches demonstrates major changes in planform characteristics. Sinuosity in all reaches decreased from 2.6 to 1.7, average wavelength of bends has increased from 200 to 500 m, and the planform has become much simpler. Changes have been progressive from downstream to upstream, with higher intensities of processes, particularly cutoffs first in downstream reaches then more recently in upstream reaches. It is suggested that channel changes represent a morphological adjustment to human interventions, such as reservoir construction and land use. However, evidence of the autogenic behaviour of meanders is highlighted in which the existence of compound meanders reveals control over the spatial variation in the reaches. The results suggest that geomorphic thresholds associated with the compound meander formation and the bend evolution should be considered, even in impacted meandering rivers, because they exert primary controls on the spatial-temporal adjustment of channels.

  19. The nature, causes and consequences of bullying at work: The Norwegian experience

    Directory of Open Access Journals (Sweden)

    Ståle Einarsen

    2005-11-01

    Full Text Available During the last decade, bullying at work has gradually emerged as an important issue in organizational research. Bullying at work is defined as the exposure to persistent or recurrent oppressive, offensive, abusive behavior in the workplace in which the aggressor may be a superior or a colleague. This paper presents the main contributions of one of the pioneer research groups in this field, The Bergen Bullying Group. Research findings relating to the very nature of the concept of bullying in the workplace, the causes and the consequences of the problem are presented. The paper also presents a conceptual framework for future theory development in this field.Depuis une dizaine d’années, le harcèlement au travail est devenu un sujet de premier plan dans la recherche sur les organisations. Le harcèlement au travail est défini comme l’exposition persistante ou répétée à un comportement abusif, intimidant et blessant en milieu de travail, de la part d’un supérieur ou d’un collègue de travail. Cet article présente les principaux résultats de recherche d’un des tous premiers groupes de recherche dans ce domaine, le Bergen Bullying Group. En particulier, les résultats de recherche rattachés au concept même de harcèlement au travail, ainsi que les causes et les conséquences du problème, sont présentés. L’article présente également un cadre conceptuel pour le développement théorique dans ce domaine de recherche.Durante la última década, la intimidación (bullying en el trabajo emergió como una problemática importante en la investigación sobre las organizaciones. La intimidación en el trabajo es definida como la exposición a comportamientos persistentes o recurrentes, opresivos, ofensivos y abusivos que pueden provenir de un superior o de un colega. Este artículo presenta las principales contribuciones de uno de los grupos de investigación pioneros en este campo : el “Bergen Bullying Group”. Se presentan los

  20. From Ends to Causes (and Back Again) by Metaphor: The Paradox of Natural Selection

    Science.gov (United States)

    Blancke, Stefaan; Schellens, Tammy; Soetaert, Ronald; Van Keer, Hilde; Braeckman, Johan

    2014-01-01

    Natural selection is one of the most famous metaphors in the history of science. Charles Darwin used the metaphor and the underlying analogy to frame his ideas about evolution and its main driving mechanism into a full-fledged theory. Because the metaphor turned out to be such a powerful epistemic tool, Darwin naturally assumed that he could also…

  1. Study on noise in simultaneous geomagnetic difference data caused by the effect of Sq local-time variation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new concept is suggested on tectonomagnetic research about the noise in simultaneous geomagnetic difference data caused by the effect of Sq local-time variation, together with the method of theoretical calculation. The level of the noise and its contribution to the total noises of the differences data are analyzed. The result indicates that the noise increases linearly with the increase of the distance between the two stations in the range of 40° longitude-difference, and its increasing rate is about 0.4 nT/(°) at latitude 40°N. The example calculated at a pair of sites with longitude-difference 0.357°, shows that the noise is about one fifth of the total noises of the difference data on geomagnetic quiet-day.

  2. Annual Variation in Flowering Phenology, Pollination, Mating System, and Pollen Yield in Two Natural Populations of Schima wallichii (DC. Korth

    Directory of Open Access Journals (Sweden)

    Vinod Prasad Khanduri

    2013-01-01

    Full Text Available Background. Schima wallichii is a highly valuable tree of tropical forest in north-east Himalaya region that grows naturally in a wide range of altitudes between 750 and 2400 m asl with varying environments. Flowering phenology of tropical tree species at population level is generally ignored and therefore a detailed knowledge of flowering and fruiting patterns of important multipurpose tree species is critical to the successful management of forest genetic resources. Materials and Methods. The study was conducted at two different altitudes (i.e., 750 m and 900 m asl in the tropical semideciduous forest of north-east Himalaya. The floral phenology including flowering synchrony in the populations, anthesis, anther dehiscence, stigma receptivity, pollinators visitation frequency, and mating system including index of self-incompatibility were worked out in Schima wallichii according to the ear-marked standard methods given by various scientists for each parameter. Results. The flowering period in Schima wallichii varied from 33 to 42 days with mean synchrony of 0.54 to 0.68 between the populations. The stigma was receptive up to 2.5 days only and showed slightly protandrous type of dichogamy. Average pollen production ranged between 6.90 × 107 pollen per tree in 2007 and 15.49 × 108 pollen per tree in 2011. A three-year masting cycle was noticed in this species. The frequency of visitation of honey bees was fairly high (5.2 ± 1.12 visits/flower/hour as compared to other pollinators. The hand pollination revealed maximum fruit (74.2 ± 5.72% and seed (70.8 ± 7.46% settings. Conclusions. The variation in flowering phenology and pollen yield individually and annually along with temporal separation in anther dehiscence and pollinator’s visitation cause pollen limited reproduction, which ultimately influences the reproductive success in Schima wallichii.

  3. Single-nucleotide variations in the genes encoding the mitochondrial Hsp60/Hsp10 chaperone system and their disease-causing potential

    DEFF Research Database (Denmark)

    Bross, Peter; Li, Zhijie; Hansen, Jakob;

    2007-01-01

    Molecular chaperones assist protein folding, and variations in their encoding genes may be disease-causing in themselves or influence the phenotypic expression of disease-associated or susceptibility-conferring variations in many different genes. We have screened three candidate patient groups fo...

  4. Single-nucleotide variations in the genes encoding the mitochondrial Hsp60/Hsp10 chaperone system and their disease-causing potential

    NARCIS (Netherlands)

    Bross, Peter; Li, Zhijie; Hansen, Jakob; Hansen, Jens Jacob; Nielsen, Marit Nyholm; Corydon, Thomas Juhl; Georgopoulos, Costa; Ang, Debbie; Lundemose, Jytte Banner; Niezen-Koning, Klary; Eiberg, Hans; Yang, Huanming; Kolvraa, Steen; Bolund, Lars; Gregersen, Niels

    2007-01-01

    Molecular chaperones assist protein folding, and variations in their encoding genes may be disease-causing in themselves or influence the phenotypic expression of disease-associated or susceptibility-conferring variations in many different genes. We have screened three candidate patient groups for v

  5. Natural epigenetic variation contributes to heritable flowering divergence in a widespread asexual dandelion lineage

    NARCIS (Netherlands)

    Wilschut, Rutger; Oplaat, C.; Snoek, L.B.; Kirschner, J.; Verhoeven, K.J.F.

    2016-01-01

    Epigenetic variation has been proposed to contribute to the success of asexual plants, either as a contributor to phenotypic plasticity or by enabling transient adaptation via selection on transgenerationally stable, but reversible, epialleles. While recent studies in experimental plant populations

  6. A role for gene duplication and natural variation of gene expression in the evolution of metabolism.

    Directory of Open Access Journals (Sweden)

    Daniel J Kliebenstein

    Full Text Available BACKGROUND: Most eukaryotic genomes have undergone whole genome duplications during their evolutionary history. Recent studies have shown that the function of these duplicated genes can diverge from the ancestral gene via neo- or sub-functionalization within single genotypes. An additional possibility is that gene duplicates may also undergo partitioning of function among different genotypes of a species leading to genetic differentiation. Finally, the ability of gene duplicates to diverge may be limited by their biological function. METHODOLOGY/PRINCIPAL FINDINGS: To test these hypotheses, I estimated the impact of gene duplication and metabolic function upon intraspecific gene expression variation of segmental and tandem duplicated genes within Arabidopsis thaliana. In all instances, the younger tandem duplicated genes showed higher intraspecific gene expression variation than the average Arabidopsis gene. Surprisingly, the older segmental duplicates also showed evidence of elevated intraspecific gene expression variation albeit typically lower than for the tandem duplicates. The specific biological function of the gene as defined by metabolic pathway also modulated the level of intraspecific gene expression variation. The major energy metabolism and biosynthetic pathways showed decreased variation, suggesting that they are constrained in their ability to accumulate gene expression variation. In contrast, a major herbivory defense pathway showed significantly elevated intraspecific variation suggesting that it may be under pressure to maintain and/or generate diversity in response to fluctuating insect herbivory pressures. CONCLUSION: These data show that intraspecific variation in gene expression is facilitated by an interaction of gene duplication and biological activity. Further, this plays a role in controlling diversity of plant metabolism.

  7. Deaths from natural causes in peole with mental illness: A cohort study

    DEFF Research Database (Denmark)

    Hiroeh, Urara; Kapur, N.; Webb, Roger

    2008-01-01

    a range of psychiatric illnesses in both sexes. We observed SMRs greater than 200 in men and women with alcoholism, drug abuse, organic psychoses, dementia, and learning difficulties. Alcoholism and drug misuse in particular were important causes of premature mortality. The highest cause-specific SMRs...

  8. Changes in the repertoire of natural antibodies caused by immunization with bacterial antigens

    DEFF Research Database (Denmark)

    Shilova, N V; Navakouski, M J; Huflejt, M

    2011-01-01

    The repertoire of natural anti-glycan antibodies in naïve chickens and in chickens immunized with bacteria Burkholderia mallei, Burkholderia pseudomallei, and Francisella tularensis as well as with peptides from an outer membrane protein of B. pseudomallei was studied. A relatively restricted...... pattern of natural antibodies (first of all IgY against bacterial cell wall peptidoglycan fragments, L-Rha, and core N-acetyllactosamine) shrank and, moreover, the level of detectable antibodies decreased as a result of immunization....

  9. Intelligence in early adulthood and mortality from natural and unnatural causes in middle-aged Danish men

    DEFF Research Database (Denmark)

    Meincke, Rikke Hodal; Mortensen, Erik Lykke; Avlund, Kirsten;

    2014-01-01

    High intelligence early in life has consistently been associated with decreased mortality, but the mechanisms are still not fully understood. In this cohort study, we examined the association between intelligence in early adulthood and later mortality from natural and unnatural causes taking birth...

  10. Diurnal and circadian variation of sleep and alertness in men vs. naturally cycling women.

    Science.gov (United States)

    Boivin, Diane B; Shechter, Ari; Boudreau, Philippe; Begum, Esmot Ara; Ng Ying-Kin, Ng Mien Kwong

    2016-09-27

    This study quantifies sex differences in the diurnal and circadian variation of sleep and waking while controlling for menstrual cycle phase and hormonal contraceptive use. We compared the diurnal and circadian variation of sleep and alertness of 8 women studied during two phases of the menstrual cycle and 3 women studied during their midfollicular phase with that of 15 men. Participants underwent an ultradian sleep-wake cycle (USW) procedure consisting of 36 cycles of 60-min wake episodes alternating with 60-min nap opportunities. Core body temperature (CBT), salivary melatonin, subjective alertness, and polysomnographically recorded sleep were measured throughout this procedure. All analyzed measures showed a significant diurnal and circadian variation throughout the USW procedure. Compared with men, women demonstrated a significant phase advance of the CBT but not melatonin rhythms, as well as an advance in the diurnal and circadian variation of sleep measures and subjective alertness. Furthermore, women experienced an increased amplitude of the diurnal and circadian variation of alertness, mainly due to a larger decline in the nocturnal nadir. Our results indicate that women are likely initiating sleep at a later circadian phase than men, which may be one factor contributing to the increased susceptibility to sleep disturbances reported in women. Lower nighttime alertness is also observed, suggesting a physiological basis for a greater susceptibility to maladaptation to night shift work in women.

  11. Exploring patterns of variation in amphipod assemblages at multiple spatial scales: natural variability versus coastal aquaculture effect

    OpenAIRE

    2013-01-01

    A 5-factor design survey was carried out to examine the spatial distribution at different scales of amphipod assemblages and sedimentary variables in soft bottoms adjacent to coastal aquaculture installations. Natural variability of sediment variables showed the highest values at the scales of sites (10s of meters) and locality (1 to 10 km), while the greatest component of variation of amphipod assemblages occurred among replicates (on the scale of meters). Regarding the influence of coastal ...

  12. Genome-wide association implicates numerous genes and pleiotropy underlying ecological trait variation in natural populations of Populus trichocarpa

    Energy Technology Data Exchange (ETDEWEB)

    McKown, Athena [University of British Columbia, Vancouver; Klapste, Jaroslav [University of British Columbia, Vancouver; Guy, Robert [University of British Columbia, Vancouver; Geraldes, Armando [University of British Columbia, Vancouver; Porth, Ilga [University of British Columbia, Vancouver; Hannemann, Jan [University of Victoria, Canada; Friedmann, Michael [University of British Columbia, Vancouver; Muchero, Wellington [ORNL; Tuskan, Gerald A [ORNL; Ehlting, Juergen [University of Victoria, Canada; Cronk, Quentin [University of British Columbia, Vancouver; El-Kassaby, Yousry [University of British Columbia, Vancouver; Mansfield, Shawn [University of British Columbia, Vancouver; Douglas, Carl [University of British Columbia, Vancouver

    2014-01-01

    To uncover the genetic basis of phenotypic trait variation, we used 448 unrelated wild accessions of black cottonwood (Populus trichocarpa Torr. & Gray) from natural populations throughout western North America. Extensive information from large-scale trait phenotyping (with spatial and temporal replications within a common garden) and genotyping (with a 34K Populus SNP array) of all accessions were used for gene discovery in a genome-wide association study (GWAS).

  13. Natural variation in life history and aging phenotypes is associated with mitochondrial DNA deletion frequency in Caenorhabditis briggsae

    Directory of Open Access Journals (Sweden)

    Smith Samson W

    2011-01-01

    Full Text Available Abstract Background Mutations that impair mitochondrial functioning are associated with a variety of metabolic and age-related disorders. A barrier to rigorous tests of the role of mitochondrial dysfunction in aging processes has been the lack of model systems with relevant, naturally occurring mitochondrial genetic variation. Toward the goal of developing such a model system, we studied natural variation in life history, metabolic, and aging phenotypes as it relates to levels of a naturally-occurring heteroplasmic mitochondrial ND5 deletion recently discovered to segregate among wild populations of the soil nematode, Caenorhabditis briggsae. The normal product of ND5 is a central component of the mitochondrial electron transport chain and integral to cellular energy metabolism. Results We quantified significant variation among C. briggsae isolates for all phenotypes measured, only some of which was statistically associated with isolate-specific ND5 deletion frequency. We found that fecundity-related traits and pharyngeal pumping rate were strongly inversely related to ND5 deletion level and that C. briggsae isolates with high ND5 deletion levels experienced a tradeoff between early fecundity and lifespan. Conversely, oxidative stress resistance was only weakly associated with ND5 deletion level while ATP content was unrelated to deletion level. Finally, mean levels of reactive oxygen species measured in vivo showed a significant non-linear relationship with ND5 deletion level, a pattern that may be driven by among-isolate variation in antioxidant or other compensatory mechanisms. Conclusions Our findings suggest that the ND5 deletion may adversely affect fitness and mitochondrial functioning while promoting aging in natural populations, and help to further establish this species as a useful model for explicit tests of hypotheses in aging biology and mitochondrial genetics.

  14. Natural variation in the Pto pathogen resistance gene within species of wild tomato (Lycopersicon). I. Functional analysis of Pto alleles.

    Science.gov (United States)

    Rose, Laura E; Langley, Charles H; Bernal, Adriana J; Michelmore, Richard W

    2005-09-01

    Disease resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) in the cultivated tomato, Lycopersicon esculentum, and the closely related L. pimpinellifolium is triggered by the physical interaction between plant disease resistance protein, Pto, and the pathogen avirulence protein, AvrPto. To investigate the extent to which variation in the Pto gene is responsible for naturally occurring variation in resistance to Pst, we determined the resistance phenotype of 51 accessions from seven species of Lycopersicon to isogenic strains of Pst differing in the presence of avrPto. One-third of the plants displayed resistance specifically when the pathogen expressed AvrPto, consistent with a gene-for-gene interaction. To test whether this resistance in these species was conferred specifically by the Pto gene, alleles of Pto were amplified and sequenced from 49 individuals and a subset (16) of these alleles was tested in planta using Agrobacterium-mediated transient assays. Eleven alleles conferred a hypersensitive resistance response (HR) in the presence of AvrPto, while 5 did not. Ten amino acid substitutions associated with the absence of AvrPto recognition and HR were identified, none of which had been identified in previous structure-function studies. Additionally, 3 alleles encoding putative pseudogenes of Pto were isolated from two species of Lycopersicon. Therefore, a large proportion, but not all, of the natural variation in the reaction to strains of Pst expressing AvrPto can be attributed to sequence variation in the Pto gene.

  15. Copy number variation of ribosomal DNA and Pokey transposons in natural populations of Daphnia

    Directory of Open Access Journals (Sweden)

    Eagle Shannon HC

    2012-03-01

    Full Text Available Abstract Background Despite their ubiquity and high diversity in eukaryotic genomes, DNA transposons are rarely encountered in ribosomal DNA (rDNA. In contrast, R-elements, a diverse group of non-LTR retrotransposons, specifically target rDNA. Pokey is a DNA transposon that targets a specific rDNA site, but also occurs in many other genomic locations, unlike R-elements. However, unlike most DNA transposons, Pokey has been a stable component of Daphnia genomes for over 100 million years. Here we use qPCR to estimate the number of 18S and 28S ribosomal RNA genes and Pokey elements in rDNA (rPokey, as well as other genomic locations (gPokey in two species of Daphnia. Our goals are to estimate the correlation between (1 the number of 18S and 28S rRNA genes, (2 the number of 28S genes and rPokey, and (3 the number of rPokey and gPokey. In addition, we ask whether Pokey number and distribution in both genomic compartments are affected by differences in life history between D. pulex and D. pulicaria. Results We found differences in 18S and 28S gene number within isolates that are too large to be explained by experimental variation. In general, Pokey number within isolates is modest (Pokey. There is no correlation between the number of rRNA genes and rPokey, or between rPokey and gPokey. However, we identified three isolates with unusually high numbers of both rPokey and gPokey, which we infer is a consequence of recent transposition. We also detected other rDNA insertions (rInserts that could be degraded Pokey elements, R- elements or the divergent PokeyB lineage recently detected in the Daphnia genome sequence. Unlike rPokey, rInserts are positively correlated with rRNA genes, suggesting that they are amplified by the same mechanisms that amplify rDNA units even though rPokey is not. Overall, Pokey frequency and distribution are similar in D. pulex and D. pulicaria suggesting that differences in life history have no impact on Pokey. Conclusions The

  16. Inter-clinic variation in the chances of natural conception of subfertile couples

    NARCIS (Netherlands)

    Tjon-Kon-Fat, R. I.; Lar, D. N.; Steyerberg, E. W.; Broekmans, F. J.; Hompes, P.; Mol, B. W. J.; Steures, P.; Bossuyt, P. M. M.; van der Veen, F.; van der Steeg, J. W.; Eijkemans, M. J. C.

    2013-01-01

    Are there differences between clinics in the chances of natural conception of couples? We found significant differences between clinics in the couples natural conception chances, which could not be explained by differences in characteristics of the patients or the clinics. In pooled data from multip

  17. Causes and prevention of corrosion in carbon steel natural gas coolers

    Energy Technology Data Exchange (ETDEWEB)

    Kotwica, D.J.; Minevski, L. [BetzDearborn, The Woodlands, TX (United States)

    1998-12-31

    Two case histories in which high pressure natural gas coolers had failed due to the presence of carbon dioxide are reviewed. CO{sub 2} along with CO and H{sub 2}S are acid gases usually present in natural gas feeds. Carbonic acid can form in aqueous condensate, lowering the pH and locally corroding mild steel tube metal. Stress corrosion cracking (SCC) can occur in tubing containing residual tensile stresses from welding or manufacturing. Bicarbonates and carbonates concentrated in condensate from CO{sub 2} and CO present in natural gas are required to produce SCC. Cathodic depolarizers such as oxygen in conjunction with the presence of carbonic acid will increase the corrosion rate of mild steel. Oxygen also increases the susceptibility of mild steel to carbonate SCC.

  18. Analysis of natural allelic variation at seed dormancy loci of Arabidopsis thaliana

    NARCIS (Netherlands)

    Alonso-Blanco, C.; Bentsink, L.; Hanhart, C.J.; Vries, de M.H.C.; Koornneef, M.

    2003-01-01

    Arabidopsis accessions differ largely in their seed dormancy behavior. To understand the genetic basis of this intraspecific variation we analyzed two accessions: the laboratory strain Landsberg erecta (Ler) with low dormancy and the strong-dormancy accession Cape Verde Islands (Cvi). We used a quan

  19. Natural variation at Strubbelig Receptor Kinase 3 drives immune-triggered incompatibilities between Arabidopsis thaliana accessions

    NARCIS (Netherlands)

    Alcazar, R.; Garcia, A.V.; Kronholm, I.; Meaux, De J.; Koornneef, M.; Parker, J.E.; Reymond, M.

    2010-01-01

    Accumulation of genetic incompatibilities within species can lead to reproductive isolation and, potentially, speciation. In this study, we show that allelic variation at SRF3 (Strubbelig Receptor Family 3), encoding a receptor-like kinase, conditions the occurrence of incompatibility between Arabid

  20. Natural variation for gene expression responses to abiotic stress in maize.

    Science.gov (United States)

    Waters, Amanda J; Makarevitch, Irina; Noshay, Jaclyn; Burghardt, Liana T; Hirsch, Candice N; Hirsch, Cory D; Springer, Nathan M

    2017-02-01

    Plants respond to abiotic stress through a variety of physiological, biochemical, and transcriptional mechanisms. Many genes exhibit altered levels of expression in response to abiotic stress, which requires concerted action of both cis- and trans-regulatory features. In order to study the variability in transcriptome response to abiotic stress, RNA sequencing was performed using 14-day-old maize seedlings of inbreds B73, Mo17, Oh43, PH207 and B37 under control, cold and heat conditions. Large numbers of genes that responded differentially to stress between parental inbred lines were identified. RNA sequencing was also performed on similar tissues of the F1 hybrids produced by crossing B73 and each of the three other inbred lines. By evaluating allele-specific transcript abundance in the F1 hybrids, we were able to measure the abundance of cis- and trans-regulatory variation between genotypes for both steady-state and stress-responsive expression differences. Although examples of trans-regulatory variation were observed, cis-regulatory variation was more common for both steady-state and stress-responsive expression differences. The genes with cis-allelic variation for response to cold or heat stress provided an opportunity to study the basis for regulatory diversity.

  1. Running vacuum in the Universe and the time variation of the fundamental constants of Nature

    CERN Document Server

    Fritzsch, Harald; Sola, Joan

    2016-01-01

    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 (RVM's) of the cosmic evolution. Recently, compelling evidence has been provided showing that these models are able to fit the main cosmological data (SNIa+BAO+H(z)+LSS+BBN+CMB) significantly better than the concordance $\\Lambda$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 of $\\gtrsim3\\sigma$. Here we use such remarkable status of the RVM's 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 variation of the dark matter particles should be necessarily involved in the total mass vari...

  2. Allelic heterogeneity and trade-off shape natural variation for response to soil micronutrient.

    Directory of Open Access Journals (Sweden)

    Seifollah Poormohammad Kiani

    Full Text Available As sessile organisms, plants have to cope with diverse environmental constraints that may vary through time and space, eventually leading to changes in the phenotype of populations through fixation of adaptive genetic variation. To fully comprehend the mechanisms of evolution and make sense of the extensive genotypic diversity currently revealed by new sequencing technologies, we are challenged with identifying the molecular basis of such adaptive variation. Here, we have identified a new variant of a molybdenum (Mo transporter, MOT1, which is causal for fitness changes under artificial conditions of both Mo-deficiency and Mo-toxicity and in which allelic variation among West-Asian populations is strictly correlated with the concentration of available Mo in native soils. In addition, this association is accompanied at different scales with patterns of polymorphisms that are not consistent with neutral evolution and show signs of diversifying selection. Resolving such a case of allelic heterogeneity helps explain species-wide phenotypic variation for Mo homeostasis and potentially reveals trade-off effects, a finding still rarely linked to fitness.

  3. On the Nature of Syntactic Variation: Evidence from Complex Predicates and Complex Word-Formation.

    Science.gov (United States)

    Snyder, William

    2001-01-01

    Provides evidence from child language acquisition and comparative syntax for existence of a syntactic parameter in the classical sense of Chomsky (1981), with simultaneous effects on syntactic argument structure. Implications are that syntax is subject to points of substantive parametric variation as envisioned in Chomsky, and the time course of…

  4. Segregating YKU80 and TLC1 alleles underlying natural variation in telomere properties in wild yeast.

    Directory of Open Access Journals (Sweden)

    Gianni Liti

    2009-09-01

    Full Text Available In yeast, as in humans, telomere length varies among individuals and is controlled by multiple loci. In a quest to define the extent of variation in telomere length, we screened 112 wild-type Saccharomyces sensu stricto isolates. We found extensive telomere length variation in S. paradoxus isolates. This phenotype correlated with their geographic origin: European strains were observed to have extremely short telomeres (400 bp. Insertions of a URA3 gene near telomeres allowed accurate analysis of individual telomere lengths and telomere position effect (TPE. Crossing the American and European strains resulted in F1 spores with a continuum of telomere lengths consistent with what would be predicted if many quantitative trait loci (QTLs were involved in length maintenance. Variation in TPE is similarly quantitative but only weakly correlated with telomere length. Genotyping F1 segregants indicated several QTLs associated with telomere length and silencing variation. These QTLs include likely candidate genes but also map to regions where there are no known genes involved in telomeric properties. We detected transgressive segregation for both phenotypes. We validated by reciprocal hemizygosity that YKU80 and TLC1 are telomere-length QTLs in the two S. paradoxus subpopulations. Furthermore, we propose that sequence divergence within the Ku heterodimer generates negative epistasis within one of the allelic combinations (American-YKU70 and European-YKU80 resulting in very short telomeres.

  5. WormQTL—public archive and analysis web portal for natural variation data in Caenorhabditis spp

    NARCIS (Netherlands)

    Snoek, L.B.; Velde, van der K.J.; Arends, D.; Li, Y.; Beyer, A.; Elvin, M.; Fisher, J.; Hajnal, A.; Hengartner, M.; Poulin, G.; Rodriguez Sanchez, M.; Schmid, T.; Schrimpf, S.; Xue, F.; Jansen, R.C.; Kammenga, J.E.; Swertz, M.A.

    2013-01-01

    Here, we present WormQTL (http://www.wormqtl.org), an easily accessible database enabling search, comparative analysis and meta-analysis of all data on variation in Caenorhabditis spp. Over the past decade, Caenorhabditis elegans has become instrumental for molecular quantitative genetics and the sy

  6. WormQTL-public archive and analysis web portal for natural variation data in Caenorhabditis spp

    NARCIS (Netherlands)

    Snoek, L. Basten; Van der Velde, K. Joeri; Arends, Danny; Li, Yang; Beyer, Antje; Elvin, Mark; Fisher, Jasmin; Hajnal, Alex; Hengartner, Michael O.; Poulin, Gino B.; Rodriguez, Miriam; Schmid, Tobias; Schrimpf, Sabine; Xue, Feng; Jansen, Ritsert C.; Kammenga, Jan E.; Swertz, Morris A.

    2013-01-01

    Here, we present WormQTL (http://www.wormqtl.org), an easily accessible database enabling search, comparative analysis and meta-analysis of all data on variation in Caenorhabditis spp. Over the past decade, Caenorhabditis elegans has become instrumental for molecular quantitative genetics and the sy

  7. Analysis of Original Causes of Reed Fires in Zhalong Nature Wetland Reserve in Heilongjiang Province

    Institute of Scientific and Technical Information of China (English)

    WANG Mingyu; SHU Lifu; TIAN Xiaorui; WANG Zhicheng

    2006-01-01

    In recent years, serious reed fires occurred in Zhalong Nature Reserve in Heilongjiang Province in China. From 19th to 28th of March 2005, 12 fires occurred in Zhalong Nature Reserve, and the fires spread to Qiqihaer City, Duerberte Mongolian Autonomous County, Lindian County and Daqing City. The burned area was about 18 666 ha. Meteorological factor was the leading factor of its fire environment in Zhalong Nature Reserve, which came into being for a long time. Long-term drought and shortage of rain made the reed and meadow withered and yellow and thus greatly reduced the water content of withered fallen leaves and humus. Much fuel was accumulated and became dry, thus forming the fire environment. Fires in Zhalong Nature Reserve were mainly strong surface fires accompanied by the spread of underground fire. It was extremely easy for reed to burn and spread very quickly. Once a fire broke out, it could spread rapidly to a scene of large fire area, and sometimes it could burn for a long time. Due to lack of correct understanding of the wetland fire and inconvenient wetland traffic, it was unable to find and put out wetland fire in time to save life and property early.

  8. Dynamics and distribution of natural and human-caused coastal hypoxia

    Directory of Open Access Journals (Sweden)

    N. N. Rabalais

    2009-10-01

    Full Text Available Water masses can become undersaturated with oxygen when natural processes alone or in combination with anthropogenic processes create enough carbon that is aerobically decomposed faster than the rate of oxygen re-aeration. The dominant natural processes usually involved are photosynthetic carbon production and microbial respiration. The re-aeration rate is indirectly related to its isolation from the surface layer. Hypoxic water masses (<2 mg L−1, or approximately 30% saturation can form, therefore, under "natural" conditions, and is more likely to occur in marine systems when the water residence time is extended, water exchange and ventilation is minimal, stratification occurs, and where carbon production and export to the bottom layer are relatively high. Hypoxia has occurred throughout geological time and naturally occurs in oxygen minimum zones, deep basins, eastern boundary upwelling systems and fjords. Hypoxia development and continuation in many areas of the world's coastal ocean is accelerated by human activities, especially where nutrient loading increased in the Anthropocene. This higher loading set in motion a cascading set of events related to eutrophication. Nutrient loading is likely to increase further as population growth and resource intensification rises, especially in developing countries dependent on crops using fertilizers, and it is likely that the occurrence and persistence of hypoxia will be even more widespread and have more impacts than presently observed. Climate change will further complicate the causative factors.

  9. Genome Size Variation in Central European Species of Cirsium (Compositae) and their Natural Hybrids

    OpenAIRE

    Bureš, Petr; Wang, Yi-Feng; Horová, Lucie; Suda, Jan

    2004-01-01

    • Background and Aims Nuclear DNA amounts of 12 diploid and one tetraploid taxa and 12 natural interspecific hybrids of Cirsium from 102 populations in the Czech Republic, Austria, Slovakia and Hungary were estimated.

  10. Natural Ferrihydrite as an Agent for Reducing Turbidity Caused by Suspended Clays

    Science.gov (United States)

    The turbidity of water can be reduced by the addition of positively charged compounds which coagulate negatively charged clay particles in suspension causing them to flocculate. This research was conducted to determine the effectiveness of the Fe oxide mineral ferrihydrite as a flocculating agent fo...

  11. The Nature, Extent and Causes of Abuse of Children with Disabilities in Schools in Botswana

    Science.gov (United States)

    Shumba, Almon; Abosi, Okey C.

    2011-01-01

    Studies show that the exact number of children with disabilities in Botswana is unknown. A study on child abuse sought to determine: the forms of child abuse perpetrated on children with disabilities; the extent of child abuse; and the causes of child abuse of children with disabilities. A questionnaire on child abuse was adapted and used to…

  12. Modeling Modern Methane Emissions from Natural Wetlands. 2; Interannual Variations 1982-1993

    Science.gov (United States)

    Walter, Bernadette P.; Heimann, Martin; Mattews, Elaine; Hansen, James E. (Technical Monitor)

    2001-01-01

    A global run of a process-based methane model [Walter et al., this issue] is performed using high-frequency atmospheric forcing fields from ECMWF reanalyses of the period from 1982 to 1993. We calculate global annual methane emissions to be 260 Tg/ yr. 25% of methane emissions originate from wetlands north of 30 deg. N. Only 60% of the produced methane is emitted, while the rest is re-oxidized. A comparison of zonal integrals of simulated global wetland emissions and results obtained by an inverse modeling approach shows good agreement. In a test with data from two wetlands, the seasonality of simulated and observed methane emissions agrees well. The effects of sub-grid scale variations in model parameters and input data are examined. Modeled methane emissions show high regional, seasonal and interannual variability. Seasonal cycles of methane emissions are dominated by temperature in high latitude wetlands, and by changes in the water table in tropical wetlands. Sensitivity tests show that +/- 1 C changes in temperature lead to +/- 20 % changes in methane emissions from wetlands. Uniform changes of +/- 20% in precipitation alter methane emissions by about +/- 18%. Limitations in the model are analyzed. Simulated interannual variations in methane emissions from wetlands are compared to observed atmospheric growth rate anomalies. Our model simulation results suggest that contributions from other sources than wetlands and/or the sinks are more important in the tropics than north-of 30 deg. N. In higher northern latitudes, it seems that a large part, of the observed interannual variations can be explained by variations in wetland emissions. Our results also suggest that reduced wetland emissions played an important role in the observed negative methane growth rate anomaly in 1992.

  13. Population variation and natural selection on leaf traits in cork oak throughout its distribution range

    Science.gov (United States)

    Ramírez-Valiente, José Alberto; Valladares, Fernando; Sánchez-Gómez, David; Delgado, Antonio; Aranda, Ismael

    2014-07-01

    A central issue in evolutionary biology is the exploration of functional trait variation among populations and the extent to which this variation has adaptive value. It was recently proposed that specific leaf area (SLA), leaf nitrogen concentration per mass (Nmass) and water use efficiency in cork oak play an important role in adaptation to water availability in the environment. In order to investigate this hypothesis, we explored, first, whether there was population-level variation in cork oak (Quercus suber) for these functional traits throughout its distribution range; if this were the case, it would be consistent with the hypothesis that different rainfall patterns have led to ecotypic differentiation in this species. Second, we studied whether the population-level variation matched short-term selection on these traits under different water availability conditions using two fitness components: survival and growth. We found high population-level differentiation in SLA and Nmass, with populations from dry places exhibiting the lowest values for SLA and Nmass. Likewise, reduced SLA had fitness benefits in terms of growth for plants under dry conditions. However, contrary to our expectations, we did not find any pattern of association between functional traits and survival in nine-year-old saplings despite considerable drought during one year of the study period. These results together with findings from the literature suggest that early stages of development are the most critical period for this species. Most importantly, these findings suggest that cork oak saplings have a considerable potential to cope with dry conditions. This capacity to withstand aridity has important implications for conservation of cork oak woodlands under the ongoing climate change.

  14. The nature, causes and consequences of bullying at work: The Norwegian experience

    OpenAIRE

    Ståle Einarsen

    2005-01-01

    During the last decade, bullying at work has gradually emerged as an important issue in organizational research. Bullying at work is defined as the exposure to persistent or recurrent oppressive, offensive, abusive behavior in the workplace in which the aggressor may be a superior or a colleague. This paper presents the main contributions of one of the pioneer research groups in this field, The Bergen Bullying Group. Research findings relating to the very nature of the concept of bullying in ...

  15. Electrophoretically detectable protein variation in natural populations of the lone star tick, Amblyomma americanum (Acari: Ixodidae).

    Science.gov (United States)

    Hilburn, L R; Sattler, P W

    1986-08-01

    Nine populations of Amblyomma americanum (L.) were examined electrophoretically for variation of 21 enzymes. Only three enzymes were not polymorphic and the average heterozygosity per individual (h) for the species was 0.085 with a range of 0.077 to 0.110, comparing well with values in other arthropods. The average Nei identity value for pairwise comparisons among the nine populations was high, 0.994 +/- 0.004 (I +/- SD). These high identity values and the absence of geographic structuring of the protein variation suggest that this species is genetically homogeneous. Normal levels of genic variability within and a lack of divergence between populations were not predicted by models developed to describe these genetic characteristics on the basis of the heterogeneities encountered by parasites in their environment. An analysis of data from several different species of ticks suggests host mobility and abundance, as well as tick abundance and selectivity in choosing a host, are important parameters in determining genetic variation in these ectoparasites.

  16. Impurities and Electronic Property Variations of Natural MoS 2 Crystal Surfaces

    KAUST Repository

    Addou, Rafik

    2015-09-22

    Room temperature X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICPMS), high resolution Rutherford backscattering spectrometry (HR-RBS), Kelvin probe method, and scanning tunneling microscopy (STM) are employed to study the properties of a freshly exfoliated surface of geological MoS2 crystals. Our findings reveal that the semiconductor 2H-MoS2 exhibits both n- and p-type behavior, and the work function as measured by the Kelvin probe is found to vary from 4.4 to 5.3 eV. The presence of impurities in parts-per-million (ppm) and a surface defect density of up to 8% of the total area could explain the variation of the Fermi level position. High resolution RBS data also show a large variation in the MoSx composition (1.8 < x < 2.05) at the surface. Thus, the variation in the conductivity, the work function, and stoichiometry across small areas of MoS2 will have to be controlled during crystal growth in order to provide high quality uniform materials for future device fabrication. © 2015 American Chemical Society.

  17. Modelling seasonal variations of natural radioactivity in soils: A case study in southern Italy

    Science.gov (United States)

    Guagliardi, Ilaria; Rovella, Natalia; Apollaro, Carmine; Bloise, Andrea; Rosa, Rosanna De; Scarciglia, Fabio; Buttafuoco, Gabriele

    2016-12-01

    The activity of natural radionuclides in soil has become an environmental concern for local public and national authorities because of the harmful effects of radiation exposure on human health. In this context, modelling and mapping the activity of natural radionuclides in soil is an important research topic. The study was aimed to model, in a spatial sense, the soil radioactivity in an urban and peri-urban soils area in southern Italy to analyse the seasonal influence on soil radioactivity. Measures of gamma radiation naturally emitted through the decay of radioactive isotopes (potassium, uranium and thorium) were analysed using a geostatistical approach to map the spatial distribution of soil radioactivity. The activity of three radionuclides was measured at 181 locations using a high-resolution ?-ray spectrometry. To take into account the influence of season, the measurements were carried out in summer and in winter. Activity data were analysed by using a geostatistical approach and zones of relatively high or low radioactivity were delineated. Among the main processes which influence natural radioactivity such as geology, geochemical, pedological, and ecological processes, results of this study showed a prominent control of radio-emission measurements by seasonal changes. Low natural radioactivity levels were measured in December associated with winter weather and moist soil conditions (due to high rainfall and low temperature), and higher activity values in July, when the soil was dry and no precipitations occurred.

  18. Modelling seasonal variations of natural radioactivity in soils: A case study in southern Italy

    Indian Academy of Sciences (India)

    Ilaria Guagliardi; Natalia Rovella; Carmine Apollaro; Andrea Bloise; Rosanna De Rosa; Fabio Scarciglia; Gabriele Buttafuoco

    2016-12-01

    The activity of natural radionuclides in soil has become an environmental concern for local public and national authorities because of the harmful effects of radiation exposure on human health. In this context, modelling and mapping the activity of natural radionuclides in soil is an important research topic. The study was aimed to model, in a spatial sense, the soil radioactivity in an urban and peri-urban soils area in southern Italy to analyse the seasonal influence on soil radioactivity. Measures of gamma radiation naturally emitted through the decay of radioactive isotopes (potassium, uranium and thorium) were analysed using a geostatistical approach to map the spatial distribution of soil radioactivity. The activity of three radionuclides was measured at 181 locations using a high-resolution γ-ray spectrometry. To take into account the influence of season, the measurements were carried out in summer and in winter. Activity data were analysed by using a geostatistical approach and zones of relatively high or low radioactivity were delineated. Among the main processes which influence natural radioactivity such as geology, geochemical, pedological, and ecological processes, results of this study showed a prominent control of radio-emission measurements by seasonal changes. Low natural radioactivity levels were measured in December associated with winter weather and moist soil conditions (due to high rainfall and low temperature), and higher activity values in July, when the soil was dry and no precipitations occurred.

  19. Seasonal variation of natural mortality factors of the guava psyllid Triozoida limbata.

    Science.gov (United States)

    Semeão, A A; Martins, J C; Picanço, M C; Chediak, M; da Silva, E M; Silva, G A

    2012-12-01

    It is important to understand how components of the agroecosystem interfere with the attack of a pest species and their seasonality in order to use these components in IPM programs. This study focused on the evaluation of the seasonality of natural control factors associated with the guava psyllid Triozoida limbata (Enderlein) in Brazil. Life-table data were collected from an experimental guava orchard during four periods that roughly represented four seasons. Natural mortality was monitored daily through the immature stages, and the relative importance of each natural mortality factor and its seasonality was determined. Significant statistical differences were observed in the mortality during the four periods (P analysis (PCA) showed some trends in the relationship of natural control agents and weather conditions. For example, the occurrence of predatory wasps was positively correlated with temperature and occurrence of winds; the occurrence of syrphids and Psyllaephagus sp. were negatively correlated with temperature and winds; and the occurrence of other generalist predators were negatively correlated with the occurrence of rainfall and photoperiod. The results showed the importance of natural mortality factors for the management of T. limbata and their changes through the different seasons which should be considered when implementing IPM programs in guava orchards.

  20. Sudden unexpected infant death: differentiating natural from abusive causes in the emergency department.

    Science.gov (United States)

    Bechtel, Kirsten

    2012-10-01

    Sudden unexpected infant deaths (SUIDs) are deaths in infants younger than 12 months that occur suddenly, unexpectedly, and without obvious cause in the emergency department (ED). Sudden infant death syndrome, the leading cause of SUID in the United States, is much more common, but fatal child abuse and neglect have been sometimes mistaken for sudden infant death syndrome. The distinction between these 2 entities can only be made after a thorough investigation of the scene, interview of caregivers, and a complete forensic autopsy. Development of ED guidelines for the reporting and evaluation of SUID, in collaboration with the local medical examiner and child death review teams, will enable ED practitioners to collect important information in a compassionate manner that will be valuable to the investigating personnel.

  1. eIF4E Resistance: Natural Variation Should Guide Gene Editing.

    Science.gov (United States)

    Bastet, Anna; Robaglia, Christophe; Gallois, Jean-Luc

    2017-02-28

    eIF4E translation initiation factors have emerged as major susceptibility factors for RNA viruses. Natural eIF4E-based resistance alleles are found in many species and are mostly variants that maintain the translation function of the protein. eIF4E genes represent major targets for engineering viral resistance, and gene-editing technologies can be used to make up for the lack of natural resistance alleles in some crops, often by knocking out eIF4E susceptibility factors. However, we report here how redundancy among eIF4E genes can restrict the efficient use of knockout alleles in breeding. We therefore discuss how gene-editing technologies can be used to design de novo functional alleles, using knowledge about the natural evolution of eIF4E genes in different species, to drive resistance to viruses without affecting plant physiology.

  2. Shrinking and Drying up of Baiyangdian Lake Wetland: A Natural or Human Cause?

    Institute of Scientific and Technical Information of China (English)

    LIU Chunlan; XIE Gaodi; HUANG Heqing

    2006-01-01

    The shrinking and drying up of wetlands in arid and semiarid areas of China have been widely observed in the recent years, but there has been no consensus on whether the aggravation is caused by human activities or by global climate warming. For a better understanding of the cause, this study investigates the dynamic changes of Baiyangdian Lake wetland over the last 40 years. It is shown that since the 1980s, Baiyangdian Lake has suffered from an insufficient water input and shrunk considerably. By using SPSS11.0, this study undertakes a detailed analysis on the significance of the effects of the possible driving factors for the degradation. It is identified that the North China Plain has been warming up significantly in recent years, which causes a significant reduction in the precipitation and inflow to the lake. Although human disturbances such as the irrigation and storage of water in reservoirs do not play a decisive role, they accelerate the degradation and their effects should be minimized.

  3. Intraspecific shape variation in horseshoe crabs: the importance of sexual and natural selection for local adaptation

    DEFF Research Database (Denmark)

    Faurby, Søren; Nielsen, Kasper Sauer Kollerup; Bussarawit, Somchai

    2011-01-01

    A morphometric analysis of the body shape of three species of horseshoe crabs was undertaken in order to infer the importance of natural and sexual selection. It was expected that natural selection would be most intense, leading to highest regional differentiation, in the American species Limulus...... from nine populations, representing three species, were analyzed using a digitizer to position sixty morphometric landmarks in a three-dimensional space. Discriminant analysis revealed strong regional structuring within a species, which suggests strong philopatry, and showed the existence...

  4. Benthic community response to habitat variation: A case of study from a natural protected area, the Celestun coastal lagoon

    Science.gov (United States)

    Pech, Daniel; Ardisson, Pedro-Luis; Hernández-Guevara, Norma A.

    2007-12-01

    Little information currently exists on spatial and temporal benthic community variations in tropical coastal lagoons. Here, the benthic community response to habitat variation in the Celestun coastal lagoon, northwest Yucatan peninsula, was seasonally examined during the 1994-1995 climatic cycle into a grid of 12 sampling sites distributed along the salinity gradient of the lagoon. Habitat variation was assessed through physical factors associated both to the water column (e.g. salinity) and the bottom sediment (e.g. sand, silt and clay fractions). The benthic community response was assessed through species diversity measures and abundance. Under the influence of climatic seasonality, variations in habitat conditions followed by changes in the benthic community characteristics were expected. Results from two-way ANOVAs showed that for the period of study, Celestun lagoon was more heterogeneous along the spatial axis of variability than along the temporal one. Multiple regression analysis showed that salinity was spatially the main factor influencing the benthic community characteristics. Temporally, the sediment characteristics were observed to exert significant effects on the species diversity characteristics but not on abundance. Other variables assessed (dissolved oxygen, pH, temperature and water column transparency) exhibited no significant covariance with species diversity and abundance. Since generated from historical data, these results have the potential to be useful as a benchmark to the establishment of monitoring programs in the light of the increasing anthropogenic pressure on the natural resources of the lagoon and surrounding coastal area.

  5. Additive genetic variation for tolerance to estrogen pollution in natural populations of Alpine whitefish (Coregonus sp., Salmonidae).

    Science.gov (United States)

    Brazzola, Gregory; Chèvre, Nathalie; Wedekind, Claus

    2014-11-01

    The evolutionary potential of natural populations to adapt to anthropogenic threats critically depends on whether there exists additive genetic variation for tolerance to the threat. A major problem for water-dwelling organisms is chemical pollution, and among the most common pollutants is 17α-ethinylestradiol (EE2), the synthetic estrogen that is used in oral contraceptives and that can affect fish at various developmental stages, including embryogenesis. We tested whether there is variation in the tolerance to EE2 within Alpine whitefish. We sampled spawners from two species of different lakes, bred them in vitro in a full-factorial design each, and studied growth and mortality of embryos. Exposure to EE2 turned out to be toxic in all concentrations we tested (≥1 ng/L). It reduced embryo viability and slowed down embryogenesis. We found significant additive genetic variation in EE2-induced mortality in both species, that is, genotypes differed in their tolerance to estrogen pollution. We also found maternal effects on embryo development to be influenced by EE2, that is, some maternal sib groups were more susceptible to EE2 than others. In conclusion, the toxic effects of EE2 were strong, but both species demonstrated the kind of additive genetic variation that is necessary for an evolutionary response to this type of pollution.

  6. Whole-Genome Resequencing Reveals Extensive Natural Variation in the Model Green Alga Chlamydomonas reinhardtii[OPEN

    Science.gov (United States)

    Hazzouri, Khaled M.; Rosas, Ulises; Bahmani, Tayebeh; Nelson, David R.; Abdrabu, Rasha; Harris, Elizabeth H.; Salehi-Ashtiani, Kourosh; Purugganan, Michael D.

    2015-01-01

    We performed whole-genome resequencing of 12 field isolates and eight commonly studied laboratory strains of the model organism Chlamydomonas reinhardtii to characterize genomic diversity and provide a resource for studies of natural variation. Our data support previous observations that Chlamydomonas is among the most diverse eukaryotic species. Nucleotide diversity is ∼3% and is geographically structured in North America with some evidence of admixture among sampling locales. Examination of predicted loss-of-function mutations in field isolates indicates conservation of genes associated with core cellular functions, while genes in large gene families and poorly characterized genes show a greater incidence of major effect mutations. De novo assembly of unmapped reads recovered genes in the field isolates that are absent from the CC-503 assembly. The laboratory reference strains show a genomic pattern of polymorphism consistent with their origin as the recombinant progeny of a diploid zygospore. Large duplications or amplifications are a prominent feature of laboratory strains and appear to have originated under laboratory culture. Extensive natural variation offers a new source of genetic diversity for studies of Chlamydomonas, including naturally occurring alleles that may prove useful in studies of gene function and the dissection of quantitative genetic traits. PMID:26392080

  7. Challenges and prospects in genome-wide quantitative trait loci mapping of standing genetic variation in natural populations.

    Science.gov (United States)

    Schielzeth, Holger; Husby, Arild

    2014-07-01

    A considerable challenge in evolutionary genetics is to understand the genetic mechanisms that facilitate or impede evolutionary adaptation in natural populations. For this, we must understand the genetic loci contributing to trait variation and the selective forces acting on them. The decreased costs and increased feasibility of obtaining genotypic data on a large number of individuals have greatly facilitated gene mapping in natural populations, particularly because organisms whose genetics have been historically difficult to study are now within reach. Here we review the methods available to evolutionary ecologists interested in dissecting the genetic basis of traits in natural populations. Our focus lies on standing genetic variation in outbred populations. We present an overview of the current state of research in the field, covering studies on both plants and animals. We also draw attention to particular challenges associated with the discovery of quantitative trait loci and discuss parallels to studies on crops, livestock, and humans. Finally, we point to some likely future developments in genetic mapping studies.

  8. The relationship between variation in size of the primordial follicle pool and age at natural menopause

    NARCIS (Netherlands)

    Depmann, M.; Faddy, M. J.; Van Der Schouw, Y. T.; Peeters, P. H M; Broer, S. L.; Kelsey, T. W.; Nelson, S. M.; Broekmans, F. J M

    2015-01-01

    Context: Menopause has been hypothesized to occur when the nongrowing follicle (NGF) number falls below a critical threshold. Age at natural menopause can be predicted using NGF numbers and this threshold. These predictions support the use of ovarian reserve tests, reflective of the ovarian follicle

  9. Natural variation in synthesis and catabolism genes influences dhurrin content in sorghum (Sorghum bicolor L. Moench)

    Science.gov (United States)

    Cyanogenic glucosides are natural compounds found in over 1,000 species of angiosperms that produce HCN and are deemed undesirable for agricultural use. However, these compounds are important components of primary defensive mechanisms of many plant species. One of the best-studied cyanogenic glucos...

  10. Large-Sample Theory for Generalized Linear Models with Non-natural Link and Random Variates

    Institute of Scientific and Technical Information of China (English)

    Jie-li Ding; Xi-ru Chen

    2006-01-01

    For generalized linear models (GLM), in the case that the regressors are stochastic and have different distributions and the observations of the responses may have different dimensionality, the asymptotic theory of the maximum likelihood estimate (MLE) of the parameters are studied under the assumption of a non-natural link function.

  11. Human disturbance causes the formation of a hybrid swarm between two naturally sympatric fish species.

    Science.gov (United States)

    Hasselman, Daniel J; Argo, Emily E; McBride, Meghan C; Bentzen, Paul; Schultz, Thomas F; Perez-Umphrey, Anna A; Palkovacs, Eric P

    2014-03-01

    Most evidence for hybrid swarm formation stemming from anthropogenic habitat disturbance comes from the breakdown of reproductive isolation between incipient species, or introgression between allopatric species following secondary contact. Human impacts on hybridization between divergent species that naturally occur in sympatry have received considerably less attention. Theory predicts that reinforcement should act to preserve reproductive isolation under such circumstances, potentially making reproductive barriers resistant to human habitat alteration. Using 15 microsatellites, we examined hybridization between sympatric populations of alewife (Alosa pseudoharengus) and blueback herring (A. aestivalis) to test whether the frequency of hybridization and pattern of introgression have been impacted by the construction of a dam that isolated formerly anadromous populations of both species in a landlocked freshwater reservoir. The frequency of hybridization and pattern of introgression differed markedly between anadromous and landlocked populations. The rangewide frequency of hybridization among anadromous populations was generally 0-8%, whereas all landlocked individuals were hybrids. Although neutral introgression was observed among anadromous hybrids, directional introgression leading to increased prevalence of alewife genotypes was detected among landlocked hybrids. We demonstrate that habitat alteration can lead to hybrid swarm formation between divergent species that naturally occur sympatrically, and provide empirical evidence that reinforcement does not always sustain reproductive isolation under such circumstances.

  12. The Destructive Cult, the Cause of Formation,Nature and Countermeasures

    Institute of Scientific and Technical Information of China (English)

    Tian Xiang, Ma

    2015-01-01

    The destructive cult is an underworld gang organization with the witchcraft and anti-social characteristics, in "Theliving god", namely the gang master, as the faith. The cause of formation bases on mankind cognitive level andsocial environment except for artificial factors. So in any time, the destructive cult has the possibility and necessityof its existence. In paper, it emphasizes that we should strengthen scientific education, open mind and sublimationof self at the same time of improving society. In this way, can only we eliminate the influence of the cult, breakdown the foundations of the cult.

  13. Genetic basis of natural variation in body pigmentation in Drosophila melanogaster.

    Science.gov (United States)

    Dembeck, Lauren M; Huang, Wen; Carbone, Mary Anna; Mackay, Trudy F C

    2015-01-01

    Body pigmentation in insects and other organisms is typically variable within and between species and is often associated with fitness. Regulatory variants with large effects at bab1, t and e affect variation in abdominal pigmentation in several populations of Drosophila melanogaster. Recently, we performed a genome wide association (GWA) analysis of variation in abdominal pigmentation using the inbred, sequenced lines of the Drosophila Genetic Reference Panel (DGRP). We confirmed the large effects of regulatory variants in bab1, t and e; identified 81 additional candidate genes; and validated 17 candidate genes (out of 28 tested) using RNAi knockdown of gene expression and mutant alleles. However, these analyses are imperfect proxies for the effects of segregating variants. Here, we describe the results of an extreme quantitative trait locus (xQTL) GWA analysis of female body pigmentation in an outbred population derived from light and dark DGRP lines. We replicated the effects on pigmentation of 28 genes implicated by the DGRP GWA study, including bab1, t and e and 7 genes previously validated by RNAi and/or mutant analyses. We also identified many additional loci. The genetic architecture of Drosophila pigmentation is complex, with a few major genes and many other loci with smaller effects.

  14. The Nature and Cause of Spectral Variability in LMC X-1

    Science.gov (United States)

    Ruhlen, L.; Smith, D. M.; Scank, J. H.

    2011-01-01

    We present the results of a long-term observation campaign of the extragalactic wind-accreting black-hole X-ray binary LMC X-1, using the Proportional Counter Array on the Rossi X-Ray Timing Explorer (RXTE). The observations show that LMC X-1's accretion disk exhibits an anomalous temperature-luminosity relation. We use deep archival RXTE observations to show that large movements across the temperature-luminosity space occupied by the system can take place on time scales as short as half an hour. These changes cannot be adequately explained by perturbations that propagate from the outer disk on a viscous timescale. We propose instead that the apparent disk variations reflect rapid fluctuations within the Compton up-scattering coronal material, which occults the inner parts of the disk. The expected relationship between the observed disk luminosity and apparent disk temperature derived from the variable occultation model is quantitatively shown to be in good agreement with the observations. Two other observations support this picture: an inverse correlation between the flux in the power-law spectral component and the fitted inner disk temperature, and a near-constant total photon flux, suggesting that the inner disk is not ejected when a lower temperature is observed.

  15. Natural variation in toxicity of wheat: potential for selection of nontoxic varieties for celiac disease patients

    NARCIS (Netherlands)

    Spaenij-Dekking, L.; Kooy-Winkelaar, Y.; Veelen, van P.; Drijfhout, J.W.; Jonker, H.H.; Soest, van L.J.M.; Smulders, M.J.M.; Bosch, H.J.; Gilissen, L.J.W.J.; Koning, de F.

    2005-01-01

    Background & Aims: Celiac disease (CD) is an intestinal disorder caused by T-cell responses to peptides derived from the gluten proteins present in wheat. Such peptides have been found both in the gliadin and glutenin proteins in gluten. The only cure for CD is a lifelong gluten-free diet. It is

  16. Natural genetic variation in the lycopene epsilon cyclase gene can enhance provitamin A biofortification of maize

    Science.gov (United States)

    Dietary micronutrient deficiencies are a major source of morbidity and mortality worldwide. Vitamin A deficiency is particularly devastating, causing blindness or corneal afflictions in 40 million children each year, and putting an additional 140-250 million at risk for related vitamin A deficiency...

  17. The Nature and Causes of Chronic Obstructive Pulmonary Disease: A Historical Perspective

    Directory of Open Access Journals (Sweden)

    C Peter W Warren

    2009-01-01

    Full Text Available Chronic obstructive pulmonary disease (COPD is the currently favoured name for the diseases formerly known as emphysema and bronchitis. COPD has been recognized for more than 200 years. Its cardinal symptoms are cough, phlegm and dyspnea, and its pathology is characterized by enlarged airspaces and obstructed airways. In the 19th century, the diagnosis of COPD depended on its symptoms and signs of a hyperinflated chest, and reduced expiratory breath sounds. The airflow obstruction evident on spirometry was identified in that century, but did not enter into clinical practice. Bronchitis, and the mechanical forces required to overcome its obstruction, was believed to be responsible for emphysema, although the inflammation present was recognized. The causes of bronchitis, and hence emphysema, included atmospheric and domestic air pollution, as well as dusty occupations. Cigarette smoking only became recognized as the dominant cause in the 20th century. The lessons learned of the risks for COPD in 19th-century Britain are very pertinent to the world today.

  18. Natural off-stoichiometry causes carrier doping in half-Heusler filled tetrahedral structures

    Science.gov (United States)

    Yu, Yonggang G.; Zhang, Xiuwen; Zunger, Alex

    2017-02-01

    The half-Heusler filled tetrahedral structures (FTSs) are zinc-blende-like compounds, where an additional atom is filling its previously empty interstitial site. The FTSs having 18 valence electrons per formula unit are an emerging family of functional materials, whose intrinsic doping trends underlying a wide range of electronic functionalities are yet to be understood. Interestingly, even pristine compounds without any attempt at impurity/chemical doping exhibit intriguing trends in the free carriers they exhibit. Applying the first principles theory of doping to a few prototype compounds in the AIVBXCIV and AIVBIXCV groups, we describe the key ingredients controlling the materials' propensity for both intrinsic and extrinsic doping: (a) The spontaneous deviations from 1:1:1 stoichiometry reflect predictable thermodynamic stability of specific competing phases. (b) Bulk ABC compounds containing 3 d elements in the B position (ZrNiSn and ZrCoSb) are predicted to be naturally 3 d rich. The B =3 d interstitials are the prevailing shallow donors, whereas the potential acceptors (e.g., Zr vacancy and Sn-on-Zr antisite) are ineffective electron killers, resulting in an overall uncompensated n -type character, even without any chemical doping. In these materials, the band edges are "natural impurity bands" due to non-Daltonian off-stoichiometry, such as B interstitials, not intrinsic bulk controlled states as in a perfect crystal. (c) Bulk ABC compounds containing 5 d elements in the B position (ZrPtSn, ZrIrSb, and TaIrGe) are predicted to be naturally C rich and A poor. This promotes the hole-producing C -on-A antisite defects rather than B -interstitial donors. The resultant p -type character (without chemical doping) therein is "latent" for C =Sn and Sb; however, as the C -on-A hole-producing acceptors are rather deep and p typeness is manifest only at high temperature or via impurity doping. In contrast, in TaIrGe (B =Ir , 5 d ) , the prevailing hole-producing Ge

  19. Determining the Cause of a Header Failure in a Natural Gas Production Facility

    Energy Technology Data Exchange (ETDEWEB)

    Matthes, S.A.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.; Holcomb, G.R.

    2007-03-01

    An investigation was made into the premature failure of a gas-header at the Rocky Mountain Oilfield Testing Center (RMOTC) natural gas production facility. A wide variety of possible failure mechanisms were considered: design of the header, deviation from normal pipe alloy composition, physical orientation of the header, gas composition and flow rate, type of corrosion, protectiveness of the interior oxide film, time of wetness, and erosion-corrosion. The failed header was examined using metallographic techniques, scanning electron microscopy, and microanalysis. A comparison of the failure site and an analogous site that had not failed, but exhibited similar metal thinning was also performed. From these studies it was concluded that failure resulted from erosion-corrosion, and that design elements of the header and orientation with respect to gas flow contributed to the mass loss at the failure point.

  20. Natural genetic variation impacts expression levels of coding, non-coding, and antisense transcripts in fission yeast

    DEFF Research Database (Denmark)

    Clément-Ziza, Mathieu; Marsellach, Francesc X.; Codlin, Sandra;

    2014-01-01

    Our current understanding of how natural genetic variation affects gene expression beyond well-annotated coding genes is still limited. The use of deep sequencing technologies for the study of expression quantitative trait loci (eQTLs) has the potential to close this gap. Here, we generated...... the first recombinant strain library for fission yeast and conducted an RNA-seq-based QTL study of the coding, non-coding, and antisense transcriptomes. We show that the frequency of distal effects (trans-eQTLs) greatly exceeds the number of local effects (cis-eQTLs) and that non-coding RNAs are as likely...

  1. The enhanced greenhouse signal versus natural variations in observed climate time series: a statistical approach

    Energy Technology Data Exchange (ETDEWEB)

    Schoenwiese, C.D. [J.W. Goethe Univ., Frankfurt (Germany). Inst. for Meteorology and Geophysics

    1995-12-31

    It is a well-known fact that human activities lead to an atmospheric concentration increase of some IR-active trace gases (greenhouse gases GHG) and that this influence enhances the `greenhouse effect`. However, there are major quantitative and regional uncertainties in the related climate model projections and the observational data reflect the whole complex of both anthropogenic and natural forcing of the climate system. This contribution aims at the separation of the anthropogenic enhanced greenhouse signal in observed global surface air temperature data versus other forcing using statistical methods such as multiple (multiforced) regressions and neural networks. The competitive natural forcing considered are volcanic and solar activity, in addition the ENSO (El Nino/Southern Oscillation) mechanism. This analysis will be extended also to the NAO (North Atlantic Oscillation) and anthropogenic sulfate formation in the troposphere

  2. The natural ocean acidification and fertilization event caused by the submarine eruption of El Hierro

    Science.gov (United States)

    Santana-Casiano, J. M.; González-Dávila, M.; Fraile-Nuez, E.; de Armas, D.; González, A. G.; Domínguez-Yanes, J. F.; Escánez, J.

    2013-01-01

    The shallow submarine eruption which took place in October 10th 2011, 1.8 km south of the island of El Hierro (Canary Islands) allowed the study of the abrupt changes in the physical-chemical properties of seawater caused by volcanic discharges. In order to monitor the evolution of these changes, seven oceanographic surveys were carried out over six months (November 2011-April 2012) from the beginning of the eruptive stage to the post-eruptive phase. Here, we present dramatic changes in the water column chemistry including large decreases in pH, striking effects on the carbonate system, decreases in the oxygen concentrations and enrichment of Fe(II) and nutrients. Our findings highlight that the same volcano which was responsible for the creation of a highly corrosive environment, affecting marine biota, has also provided the nutrients required for the rapid recuperation of the marine ecosystem. PMID:23355953

  3. Structural and functional changes in pulmonary macrophages during phagocytosis caused by natural zeolite-clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    Kruglikov, G.G.; Velichkovskii, B.T.; Garmash, T.I.; Volkogonova, V.M. (Rossiiskii Gosudarstvennyi Meditsinskii Universitet, Moscow (Russian Federation))

    1992-11-01

    Invstigates cytotoxic properties of clinoptilolite and structural and functional state of pulmonary macrophages in the course of phagocytosis caused by exposure to clinoptilolite. Investigations were carried out on white rats with quartz dust and dust of black coal from the Kemerovo coal deposit used in two reference groups. Toxic dust was administered intratracheally in saline solution, coal dust in a 1% starch solution. Pathological processes in phagocytic cells observed using electron microscopy are described. More pronounced cytotoxic effects of clinoptilolite in comparison with those of coal dust are pointed out. The following pathological phenomena in cells were observed: vigorous phagocytic processes on clinoptilolite particles; active lysosome reaction and lipid accumulation; irreversible changes in mitochondrea; development of destructive types of macrophages. 5 refs.

  4. Variations in the relation between education and cause-specific mortality in 19 European populations: a test of the "fundamental causes" theory of social inequalities in health.

    Science.gov (United States)

    Mackenbach, Johan P; Kulhánová, Ivana; Bopp, Matthias; Deboosere, Patrick; Eikemo, Terje A; Hoffmann, Rasmus; Kulik, Margarete C; Leinsalu, Mall; Martikainen, Pekka; Menvielle, Gwenn; Regidor, Enrique; Wojtyniak, Bogdan; Östergren, Olof; Lundberg, Olle

    2015-02-01

    Link and Phelan have proposed to explain the persistence of health inequalities from the fact that socioeconomic status is a "fundamental cause" which embodies an array of resources that can be used to avoid disease risks no matter what mechanisms are relevant at any given time. To test this theory we compared the magnitude of inequalities in mortality between more and less preventable causes of death in 19 European populations, and assessed whether inequalities in mortality from preventable causes are larger in countries with larger resource inequalities. We collected and harmonized mortality data by educational level on 19 national and regional populations from 16 European countries in the first decade of the 21st century. We calculated age-adjusted Relative Risks of mortality among men and women aged 30-79 for 24 causes of death, which were classified into four groups: amenable to behavior change, amenable to medical intervention, amenable to injury prevention, and non-preventable. Although an overwhelming majority of Relative Risks indicate higher mortality risks among the lower educated, the strength of the education-mortality relation is highly variable between causes of death and populations. Inequalities in mortality are generally larger for causes amenable to behavior change, medical intervention and injury prevention than for non-preventable causes. The contrast between preventable and non-preventable causes is large for causes amenable to behavior change, but absent for causes amenable to injury prevention among women. The contrast between preventable and non-preventable causes is larger in Central & Eastern Europe, where resource inequalities are substantial, than in the Nordic countries and continental Europe, where resource inequalities are relatively small, but they are absent or small in Southern Europe, where resource inequalities are also large. In conclusion, our results provide some further support for the theory of "fundamental causes". However

  5. Experimental approaches to studying the nature and impact of splicing variation in zebrafish.

    Science.gov (United States)

    Keightley, M C; Markmiller, S; Love, C G; Rasko, J E J; Lieschke, G J; Heath, J K

    2016-01-01

    From a fixed number of genes carried in all cells, organisms create considerable diversity in cellular phenotype through differential regulation of gene expression. One prevalent source of transcriptome diversity is alternative pre-mRNA splicing, which is manifested in many different forms. Zebrafish models of splicing dysfunction due to mutated spliceosome components provide opportunity to link biochemical analyses of spliceosome structure and function with whole organism phenotypic outcomes. Drawing from experience with two zebrafish mutants: cephalophŏnus (a prpf8 mutant, isolated for defects in granulopoiesis) and caliban (a rnpc3 mutant, isolated for defects in digestive organ development), we describe the use of glycerol gradient sedimentation and native gel electrophoresis to resolve components of aberrant splicing complexes. We also describe how RNAseq can be employed to examine relatively rare alternative splicing events including intron retention. Such experimental approaches in zebrafish can promote understanding of how splicing variation and dysfunction contribute to phenotypic diversity and disease pathogenesis.

  6. Reappraisal of the limit on the variation in α implied by the Oklo natural fission reactors

    Science.gov (United States)

    Davis, Edward D.; Hamdan, Leila

    2015-07-01

    Background: A signature of many dynamical models of dark energy is that they admit variation in the fine structure constant α over cosmological time scales. Purpose: We reconsider the analysis of the sensitivity of neutron resonance energies Ei to changes in α with a view to resolving uncertainties that plague earlier treatments. Methods: We point out that with more appropriate choices of nuclear parameters, the standard estimate (from Damour and Dyson) of the sensitivity for resonances in Sm is increased by a factor of 2.5. We go on to identify and compute excitation, Coulomb, and deformation corrections. To this end, we use deformed Fermi density distributions fitted to the output of Hartree-Fock (HF) + BCS calculations (with both the SLy4 and SkM* Skyrme functionals), the energetics of the surface diffuseness of nuclei, and thermal properties of their deformation. We also invoke the eigenstate thermalization hypothesis, performing the requisite microcanonical averages with two phenomenological level densities which, via the leptodermous expansion of the level density parameter, include the effect of increased surface diffuseness. Theoretical uncertainties are assessed with the inter-model prescription of Dobaczewski et al. [J. Phys. G: Nucl. Part. Phys. 41, 074001 (2014), 10.1088/0954-3899/41/7/074001]. Results: The corrections diminish the revised Sm sensitivity but not by more than 25%. Subject to a weak and testable restriction on the change in mq/Λ (relative to the change in α ) since the time when the Oklo reactors were active (mq is the average of the u and d current quark masses, and Λ is the mass scale of quantum chromodynamics), we deduce that | αOklo-αnow|Oklo bound on changes in α is reliable. It is one order of magnitude lower than the Oklo-based bound most commonly adopted in earlier attempts to identify phenomenologically successful models of α variation.

  7. Natural variation of the nef gene in human immunodeficiency virus type 2 infections in Portugal

    OpenAIRE

    Pádua, E.; Jenkins, A.; S. Brown; Bootman, J.; Paixão, M T; Almond, N; Berry, N

    2003-01-01

    Human immunodeficiency virus type 2 (HIV-2) infections cause severe immunodeficiency in humans, although HIV-2 is associated frequently with reduced virulence and pathogenicity compared to HIV-1. Genetic determinants that play a role in HIV pathogenesis are relatively poorly understood but nef has been implicated in inducing a more pathogenic phenotype in vivo. However, relatively little is known about the role of nef in HIV-2 pathogenesis. To address this, the genetic composition of 44 nef a...

  8. Natural Variation Identifies ICARUS1, a Universal Gene Required for Cell Proliferation and Growth at High Temperatures in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Wangsheng Zhu

    2015-05-01

    Full Text Available Plants are highly sensitive to environmental changes and even small variations in ambient temperature have severe consequences on their growth and development. Temperature affects multiple aspects of plant development, but the processes and mechanisms underlying thermo-sensitive growth responses are mostly unknown. Here we exploit natural variation in Arabidopsis thaliana to identify and characterize novel components and processes mediating thermo-sensitive growth responses in plants. Phenotypic screening of wild accessions identified several strains displaying pleiotropic growth defects, at cellular and organism levels, specifically at high ambient temperatures. Positional cloning and characterization of the underlying gene revealed that ICARUS1 (ICA1, which encodes a protein of the tRNAHis guanylyl transferase (Thg1 superfamily, is required for plant growth at high temperatures. Transcriptome and gene marker analyses together with DNA content measurements show that ICA1 loss-of-function results in down regulation of cell cycle associated genes at high temperatures, which is linked with a block in G2/M transition and endoreduplication. In addition, plants with mutations in ICA1 show enhanced sensitivity to DNA damage. Characterization of additional strains that carry lesions in ICA1, but display normal growth, shows that alternative splicing is likely to alleviate the deleterious effects of some natural mutations. Furthermore, analyses of worldwide and regional collections of natural accessions indicate that ICA1 loss-of-function has arisen several times independently, and that these occur at high frequency in some local populations. Overall our results suggest that ICA1-mediated-modulation of fundamental processes such as tRNAHis maturation, modify plant growth responses to temperature changes in a quantitative and reversible manner, in natural populations.

  9. Natural and experimental evidence of viscerotropic infection caused by Leishmania tropica from North Sinai, Egypt.

    Science.gov (United States)

    Doha, Said A; Shehata, Magdi G; Fahmy, Adel R; Samy, Abdallah M

    2014-08-01

    Cutaneous leishmaniasis (CL) is a neglected clinical form that is quite prevalent in Eastern North parts of the country in Sinai Peninsula. Leishmania tropica was identified by previous reports as the causative agent responsible for viscerotropic infections in-patients and experimental animals. Here, we reported the viscerotropic infections from naturally infected rodent Gerbillus pyramidum floweri collected from North-Sinai. Footpad and tail lesions, spleenomegaly, and malformed dark-colored spleen were the characteristic CL symptoms. The spleen of the rodent found positive to amastigote impression smear. ITS-1 DNA was sequenced and revealed 100% identity of the strain in the current study to the other L. tropica sequences identified from the patients with the suspected CL and inhabited the same study area. The current findings confirmed the susceptibility of gerbil to L. tropica, and raise the concerns for the role of rodents as accidental host suffering the infections. The susceptibility of wild and experimental rodents to the same L. tropica strain was also investigated; BALB/c and G. pyramidum were more susceptible to L. tropica (24.33 ± 4.37 and 25 ± 4.58 days post-infection, respectively). Similar viscerotropic pathologies were reported in experimental infection of only golden hamster (≈ 120 days post-infection), and G. p. floweri (≈ 160 days post-infection).

  10. Variable defect structures cause the magnetic low-temperature transition in natural monoclinic pyrrhotite

    Science.gov (United States)

    Koulialias, D.; Kind, J.; Charilaou, M.; Weidler, P. G.; Löffler, J. F.; Gehring, A. U.

    2016-02-01

    Non-stoichiometric monoclinic 4C pyrrhotite (Fe7S8) is a major magnetic remanence carrier in the Earth's crust and in extraterrestrial materials. Because of its low-temperature magnetic transition around 30 K also known as Besnus transition, which is considered to be an intrinsic property, this mineral phase is easily detectable in natural samples. Although the physical properties of pyrrhotite have intensively been studied, the mechanism behind the pronounced change in magnetization at the low-temperature transition is still debated. Here we report magnetization experiments on a pyrrhotite crystal (Fe6.6S8) that consists of a 4C and an incommensurate 5C* superstructure that are different in their defect structure. The occurrence of two superstructures is magnetically confirmed by symmetric inflection points in hysteresis measurements above the transition at about 30 K. The disappearance of the inflection points and the associated change of the hysteresis parameters indicate that the two superstructures become strongly coupled to form a unitary magnetic anisotropy system at the transition. From this it follows that the Besnus transition in monoclinic pyrrhotite is an extrinsic magnetic phenomenon with respect to the 4C superstructure and therefore the physics behind it is in fact different from that of the well-known Verwey transition.

  11. Predation in Ground-Nesting Birds: an Experimental Study Using Natural Egg-Color Variation

    Directory of Open Access Journals (Sweden)

    Aurora M. Castilla

    2007-06-01

    Full Text Available We tested the hypothesis that cryptically colored eggs would suffer less predation than conspicuous eggs in the ground-nesting red-legged partridge, Alectoris rufa. We used A. rufa as a model species because it has a wide range of natural egg colors, the eggs are widely available from breeding farms, and nests are easily mimicked because they are scrapes containing no vegetation. The study was conducted in the spring of 2001 in forest and fallow fields of central Spain in Castilla La Mancha, Ciudad Real. We used 384 clutches of natural eggs that were white, white spotted, brown, or brown spotted. Within clutches, eggs were consistent in color and size; among clutches, color differences were distributed across habitats. Clutches were checked once after 2 wk of exposure. Cryptic coloration had a survival advantage that was dependent on the local suite of predators. Rodent predation was nonselective with respect to clutch color; however, avian predation was significantly higher for conspicuous clutches. In addition, there was an interaction of landscape and egg color for avian predation. In forest landscapes, the clutches with highest survival were brown spotted, whereas in fallow landscapes, brown and brown spotted clutches had higher survival than white and white potted clutches. Thus, both the predator suite and the landscape had significant effects on the value of cryptic egg coloration. Our study is relevant for conservationists and managers in charge of restocking programs in hunting areas. The release of other partridge species or their hybrids could result in hybridization with wild partridges, potentially leading to nonoptimal clutch pigmentation and reduced survival of the native species. We therefore recommend that local authorities, managers, and conservationists be cautious with the use of alien species and hybrids and release only autochthonous species of partridges within their natural ranges.

  12. Variations in timing of lithospheric failure on terrestrial planets due to chaotic nature of mantle convection

    Science.gov (United States)

    Wong, Teresa; Solomatov, Viatcheslav S.

    2016-05-01

    We perform numerical simulations of lithospheric failure in the stagnant lid regime of temperature-dependent viscosity convection, using the yield stress approach. We find that the time of failure can vary significantly for the same values of the controlling parameters due to the chaotic nature of the convective system. The general trend of the dependence of the time of lithospheric failure on the yield stress can be explained by treating lithospheric failure as a type of Rayleigh-Taylor instability. This study suggests that it is important to address not only the question of whether plate tectonics can occur on a planet but also when it would occur if conditions are favorable.

  13. Design of a Comprehensive Biochemistry and Molecular Biology Experiment: Phase Variation Caused by Recombinational Regulation of Bacterial Gene Expression

    Science.gov (United States)

    Sheng, Xiumei; Xu, Shungao; Lu, Renyun; Isaac, Dadzie; Zhang, Xueyi; Zhang, Haifang; Wang, Huifang; Qiao, Zheng; Huang, Xinxiang

    2014-01-01

    Scientific experiments are indispensable parts of Biochemistry and Molecular Biology. In this study, a comprehensive Biochemistry and Molecular Biology experiment about "Salmonella enterica" serovar Typhi Flagellar phase variation has been designed. It consisted of three parts, namely, inducement of bacterial Flagellar phase variation,…

  14. The natural ocean acidification and fertilization event caused by the submarine eruption of El Hierro

    Science.gov (United States)

    Magdalena Santana-Casiano, J.; González-Dávila, Melchor; Fraile-Nuez, Eugenio

    2014-05-01

    The shallow submarine eruption which took place in October 10th 2011, 1.8 km south of the island of El Hierro (Canary Islands) allowed the study of the abrupt changes in the physical-chemical properties of seawater caused by volcanic discharges. In order to monitor the evolution of these changes, seven oceanographic surveys were carried out over six months (November 2011-April 2012) from the beginning of the eruptive stage to the post-eruptive phase. Important changes in the water column chemistry including large decreases in pH, striking effects on the carbonate system, decreases in the oxygen concentrations and enrichment of Fe(II) and nutrients were produced. As a result of the ongoing magmatic activity, the submarine eruption produced an unprecedented episode of severe acidification and fertilization. The findings highlight that the same volcano which was responsible for the creation of a highly corrosive environment, affecting marine biota, has also provided the nutrients required for the rapid recuperation of the marine ecosystem.

  15. Acceptability of variations in question intonation in natural and synthesized American English

    Science.gov (United States)

    Syrdal, Ann K.; Jilka, Matthias

    2004-05-01

    In a previous study exploring American English question intonation, we found that some speakers deviated considerably from expected question prosody. In this study, we focus on listener-rated acceptability of the various prosodic patterns observed for yes/no and wh questions. A variety of intonational patterns realized in both question utterances recorded from five female and three male professional speakers and in questions synthesized from several TTS voices of both genders was presented to listeners. Subjects judged the acceptability of each utterance in the context of a dialogue between a travel agent and customer. We hypothesized that question utterances with the expected intonational features (phrase-final fall in wh questions, phrase-final rise in yes/no questions) would be rated as more acceptable than question utterances with deviating intonational features, and that this result would hold for both natural and synthetic speech conditions. In addition, following our previous results, we hypothesized that the unexpected intonation pattern of phrase-final falls for yes/no questions would be more acceptable for lower-pitched than for higher-pitched voices. We also varied the prominence of the interrogative pronouns in synthetic wh questions in order to see whether simulating their high intonational prominence in natural wh questions improved the acceptability of synthetic wh questions.

  16. Variation in cone and seed characters in blue pine (Pinus wallichiana) across natural distribution in western Himalayas

    Institute of Scientific and Technical Information of China (English)

    Ombir Singh; Manisha Thapliyal

    2012-01-01

    We analyzed 17 seed sources (seed stands) of Pinus wallichiana for variations present in cone and seed characters,scattered over natural distribution in north-west Himalayan states (Uttarakhand and Himachal Pradesh) of India.The significant variations were observed in cone weight,cone length,cone width,seed length,seed width,seed weight,seed germination,radicle length,and plumule length among different seed sources of the species.Significant positive correlation between seed weight,cone weight and cone width showed that seed weight in the species depend more on the cone size.Seed germination was also positively correlated with seed weight,cone weight and radicle length in the study.The estimates of variability with regard to genetic parameters for seed weight,seed germination,cone length,cone width,cone weight showed wide range of variation in the study.Seed weight showed high heritability values coupled with maximum genetic gain.Traits with such values indicate presence of good amount of heritable additive components and are under strong genetic control.The findings of the study revealed that seed sources expressed both phenotypic and genotypic differences in the seed and cone traits which might be due to the differences in genetic make up of various seed sources and environmental factors i.e.genotypic and environmental interaction.The study suggests that the seed weight should be given the top priority for the further improvement of this species.

  17. Arabidopsis thaliana natural variation reveals connections between UV radiation stress and plant pathogen-like defense responses.

    Science.gov (United States)

    Piofczyk, Thomas; Jeena, Ganga; Pecinka, Ales

    2015-08-01

    UV radiation is a ubiquitous component of solar radiation that affects plant growth and development. Here we studied growth related traits of 345 Arabidopsis thaliana accessions in response to UV radiation stress. We analyzed the genetic basis of this natural variation by genome-wide association studies, which suggested a specific candidate genomic region. RNA-sequencing of three sensitive and three resistant accessions combined with mutant analysis revealed five large effect genes. Mutations in PHE ammonia lyase 1 (PAL1) and putative kinase At1g76360 rendered Arabidopsis hypersensitive to UV stress, while loss of function from putative methyltransferase At4g22530, novel plant snare 12 (NPSN12) and defense gene activated disease resistance 2 (ADR2) conferred higher UV stress resistance. Three sensitive accessions showed strong ADR2 transcriptional activation, accumulation of salicylic acid (SA) and dwarf growth upon UV stress, while these phenotypes were much less affected in resistant plants. The phenotype of sensitive accessions resembles autoimmune reactions due to overexpression of defense related genes, and suggests that natural variation in response to UV radiation stress is driven by pathogen-like responses in Arabidopsis.

  18. Genetic Diversity Caused by Environmental Stress in Natural Populations of Niupidujuan as Revealed by RAPD Technique

    Institute of Scientific and Technical Information of China (English)

    DU Ying-da; XING Ming; YANG Zhi-yong; LIU Yan-fei; CHEN Xia

    2011-01-01

    Multiplex environmental factors are generally expected to have significant effects on genetic diversity of plant populations.In this study,randomly amplified polymorphic DNA(RAPD) technique was used to reveal the genetic diversity in the same species of four populations collected from Niupidujuan(Rhododendron chrysanthum) at different altitudes,an endangered species,endemic to Northeast China.Initially,twenty informative and reproducible primers were chosen for final RAPD analysis.A total of 152 clear bands were obtained,including 143 polymorphic ones.With the help of POPGENE software,the poly rate was calculated to be 94.07% and the evenness of amplified bands for every primer was 6.8.Additionally,the mean observed number of alleles was 1.7265 with an effective number of 1.3608.An examination of the gene indicated a diversity of 0.2162 with an information diversity index of 0.3313.For these data,the clustering blurred analysis was performed with the aid of NTSYS-pc software to define the Nei's gene diversity and the Shannon information diversity index of the four plant populations.The relationships between the genetic diversity indexes on the one hand and the geographic and climatic factors on the other hand were estimated by the Pearson correlation with SPSS 11.0 software.The results of the correlation analysis show that there were significant(P<0.05) or highly significant(P<0.01) correlations between each of the genetic diversity indexes and the different temperature which were mainly caused by the altitude different populations located.These data highlight the importance of native populations in shaping the spatial genetic structure in Niupidujuan.

  19. Learning to be different: Acquired skills, social learning, frequency dependence, and environmental variation can cause behaviourally mediated foraging specializations

    Science.gov (United States)

    Tinker, M.T.; Mangel, M.; Estes, J.A.

    2009-01-01

    Question: How does the ability to improve foraging skills by learning, and to transfer that learned knowledge, affect the development of intra-population foraging specializations? Features of the model: We use both a state-dependent life-history model implemented by stochastic dynamic programming (SDPM) and an individual-based model (IBM) to capture the dynamic nature of behavioural preferences in feeding. Variables in the SDPM include energy reserves, skill levels, energy and handling time per single prey item, metabolic rate, the rates at which skills are learned and forgotten, the effect of skills on handling time, and the relationship between energy reserves and fitness. Additional variables in the IBM include the probability of successful weaning, the logistic dynamics of the prey species with stochastic recruitment, the intensity of top-down control of prey by predators, the mean and variance in skill levels of new recruits, and the extent to which learned Information can be transmitted via matrilineal social learning. Key range of variables: We explore the effects of approaching the time horizon in the SDPM, changing the extent to which skills can improve with experience, increasing the rates of learning or forgetting of skills, changing whether the learning curve is constant, accelerating (T-shaped) or decelerating ('r'-shaped), changing both mean and maximum possible energy reserves, changing metabolic costs of foraging, and changing the rate of encounter with prey. Conclusions: The model results show that the following factors increase the degree of prey specialization observed in a predator population: (1) Experience handling a prey type can substantially improve foraging skills for that prey. (2) There is limited ability to retain complex learned skills for multiple prey types. (3) The learning curve for acquiring new foraging skills is accelerating, or J-shaped. (4) The metabolic costs of foraging are high relative to available energy reserves. (5

  20. Comparative analysis of maize (Zea mays) crop performance: natural variation, incremental improvements and economic impacts.

    Science.gov (United States)

    Leibman, Mark; Shryock, Jereme J; Clements, Michael J; Hall, Michael A; Loida, Paul J; McClerren, Amanda L; McKiness, Zoe P; Phillips, Jonathan R; Rice, Elena A; Stark, Steven B

    2014-09-01

    Grain yield from maize hybrids continues to improve through advances in breeding and biotechnology. Despite genetic improvements to hybrid maize, grain yield from distinct maize hybrids is expected to vary across growing locations due to numerous environmental factors. In this study, we examine across-location variation in grain yield among maize hybrids in three case studies. The three case studies examine hybrid improvement through breeding, introduction of an insect protection trait or introduction of a transcription factor trait associated with increased yield. In all cases, grain yield from each hybrid population had a Gaussian distribution. Across-location distributions of grain yield from each hybrid partially overlapped. The hybrid with a higher mean grain yield typically outperformed its comparator at most, but not all, of the growing locations (a 'win rate'). These results suggest that a broad set of environmental factors similarly impacts grain yields from both conventional- and biotechnology-derived maize hybrids and that grain yields among two or more hybrids should be compared with consideration given to both mean yield performance and the frequency of locations at which each hybrid 'wins' against its comparators. From an economic standpoint, growers recognize the value of genetically improved maize hybrids that outperform comparators in the majority of locations. Grower adoption of improved maize hybrids drives increases in average U.S. maize grain yields and contributes significant value to the economy.

  1. Exploring the natural variation for seedling traits and their link with seed dimensions in tomato.

    Directory of Open Access Journals (Sweden)

    Noorullah Khan

    Full Text Available The success of germination, growth and final yield of every crop depends to a large extent on the quality of the seeds used to grow the crop. Seed quality is defined as the viability and vigor attribute of a seed that enables the emergence and establishment of normal seedlings under a wide range of environments. We attempt to dissect the mechanisms involved in the acquisition of seed quality, through a combined approach of physiology and genetics. To achieve this goal we explored the genetic variation found in a RIL population of Solanum lycopersicum (cv. Moneymaker x Solanum pimpinellifolium through extensive phenotyping of seed and seedling traits under both normal and nutrient stress conditions and root system architecture (RSA traits under optimal conditions. We have identified 62 major QTLs on 21 different positions for seed, seedling and RSA traits in this population. We identified QTLs that were common across both conditions, as well as specific to stress conditions. Most of the QTLs identified for seedling traits co-located with seed size and seed weight QTLs and the positive alleles were mostly contributed by the S. lycopersicum parent. Co-location of QTLs for different traits might suggest that the same locus has pleiotropic effects on multiple traits due to a common mechanistic basis. We show that seed weight has a strong effect on seedling vigor and these results are of great importance for the isolation of the corresponding genes and elucidation of the underlying mechanisms.

  2. Relations of Naturally Occurring Variations in State Anxiety and Cognitive Functioning.

    Science.gov (United States)

    Meissel, Emily E E; Salthouse, Timothy A

    2016-08-01

    Although effects of anxiety on cognitive performance have been extensively examined, anxiety-cognition relationships are often defined by between-person relationships. The current research investigated the effects of within-person variations in state anxiety on cognitive performance based on measures from three separate sessions in a sample of 1,769 healthy adults ranging from 18 to 99 years of age. Some of the adults in the sample exhibited a wide range of state anxiety across the three sessions, whereas others were fairly stable. Although one might have expected that cognitive performance would be low only on sessions in which the level of state anxiety was high, this pattern was not evident in any of five different cognitive abilities (vocabulary, memory, reasoning, spatial relations, or perceptual speed tasks). Instead, one's average level of anxiety was a more important determinant of cognitive performance than one's current level of state anxiety. Specifically, for memory and reasoning abilities, trait anxiety alone related to decreased cognitive function, regardless of state anxiety. For spatial relations and speed abilities, low state anxiety was related to decreased cognitive function in participants with high trait anxiety.

  3. Genomic analysis of natural selection and phenotypic variation in high-altitude mongolians.

    Directory of Open Access Journals (Sweden)

    Jinchuan Xing

    Full Text Available Deedu (DU Mongolians, who migrated from the Mongolian steppes to the Qinghai-Tibetan Plateau approximately 500 years ago, are challenged by environmental conditions similar to native Tibetan highlanders. Identification of adaptive genetic factors in this population could provide insight into coordinated physiological responses to this environment. Here we examine genomic and phenotypic variation in this unique population and present the first complete analysis of a Mongolian whole-genome sequence. High-density SNP array data demonstrate that DU Mongolians share genetic ancestry with other Mongolian as well as Tibetan populations, specifically in genomic regions related with adaptation to high altitude. Several selection candidate genes identified in DU Mongolians are shared with other Asian groups (e.g., EDAR, neighboring Tibetan populations (including high-altitude candidates EPAS1, PKLR, and CYP2E1, as well as genes previously hypothesized to be associated with metabolic adaptation (e.g., PPARG. Hemoglobin concentration, a trait associated with high-altitude adaptation in Tibetans, is at an intermediate level in DU Mongolians compared to Tibetans and Han Chinese at comparable altitude. Whole-genome sequence from a DU Mongolian (Tianjiao1 shows that about 2% of the genomic variants, including more than 300 protein-coding changes, are specific to this individual. Our analyses of DU Mongolians and the first Mongolian genome provide valuable insight into genetic adaptation to extreme environments.

  4. Patterns of cuticular hydrocarbon variation and genetic similarity between natural populations of Amblyomma cajennense (Acari: Ixodidae).

    Science.gov (United States)

    Estrada-Peña, A; Guglielmone, A A; Mangold, A J; Castellá, J

    1993-10-01

    Gas chromatography has been used to analyze the variation in cuticular hydrocarbon patterns between several populations of Amblyomma cajennense. 88 compounds were detected and these could be divided into 17 groups of hydrocarbons. Heterozygosis in the populations ranges from 0% to 25.84%. Isomers for pentacosane, heptacosane and nonatriacontane are the most variable, with 13, 10 and 11 variants, respectively. Nei's genetic identity and genetic distance show that populations may be considered as regional variants of only one species: the results do not indicate the presence of sibling species. However, a relatively high genetic distance has been observed between several Cuban and continental populations, suggesting a long reproductive isolation. Gas chromatography of cuticular hydrocarbons is a good alternative to isozyme analysis for population studies, when collecting conditions do not allow the use of live ticks and only alcohol-preserved collections are available. The high number of compounds available for genetic studies will provide excellent markers for evaluating the extent of gene flow and migration of tick species.

  5. Differentially expressed genes linked to natural variation in long-term memory formation in Cotesia parasitic wasps

    Directory of Open Access Journals (Sweden)

    Joke J. F. A. Van Vugt

    2015-09-01

    Full Text Available Even though learning and memory are universal traits in the Animal Kingdom, closely related species reveal substantial variation in learning rate and memory dynamics. To determine the genetic background of this natural variation, we studied two congeneric parasitic wasp species, Cotesia glomerata and C. rubecula, which lay their eggs in caterpillars of the large and small cabbage white butterfly. A successful egg laying event serves as an unconditioned stimulus in a classical conditioning paradigm, where plant odors become associated to the encounter of a suitable host caterpillar. Depending on the host species, the number of conditioning trials and the parasitic wasp species, three different types of transcription-dependent long-term memory (LTM and one type of transcription-independent, anesthesia-resistant memory (ARM can be distinguished. To identify transcripts underlying these differences in memory formation, we isolated mRNA from parasitic wasp heads at three different time points between induction and consolidation of each of the four memory types, and for each sample three biological replicates, where after strand-specific paired-end 100 bp deep sequencing. Transcriptomes were assembled de novo and differential expression was determined for each memory type and time point after conditioning, compared to unconditioned wasps. Most differentially expressed (DE genes and antisense transcripts were only DE in one of the LTM types. Among the DE genes that were DE in two or more LTM types, were many protein kinases and phosphatases, small GTPases, receptors and ion channels. Some genes were DE in opposing directions between any of the LTM memory types and ARM, suggesting that ARM in Cotesia requires the transcription of genes inhibiting LTM or vice versa. We discuss our findings in the context of neuronal functioning, including RNA splicing and transport, epigenetic regulation, neurotransmitter/peptide synthesis and antisense transcription. In

  6. Natural Diversity in Pentose Fermentation Is Explained by Variations in Histone Deacetylases

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    Zvi Tamari

    2016-01-01

    Full Text Available The extent to which carbon flux is directed toward fermentation versus respiration differs between cell types and environmental conditions. Understanding the basic cellular processes governing carbon flux is challenged by the complexity of the metabolic and regulatory networks. To reveal the genetic basis for natural diversity in channeling carbon flux, we applied quantitative trait loci analysis by phenotyping and genotyping hundreds of individual F2 segregants of budding yeast that differ in their capacity to ferment the pentose sugar xylulose. Causal alleles were mapped to the RXT3 and PHO23 genes, two components of the large Rpd3 histone deacetylation complex. We show that these allelic variants modulate the expression of SNF1/AMPK-dependent respiratory genes. Our results suggest that over close evolutionary distances, diversification of carbon flow is driven by changes in global regulators, rather than adaptation of specific metabolic nodes. Such regulators may improve the ability to direct metabolic fluxes for biotechnological applications.

  7. Regulation of flowering in rice: two florigen genes, a complex gene network, and natural variation.

    Science.gov (United States)

    Tsuji, Hiroyuki; Taoka, Ken-ichiro; Shimamoto, Ko

    2011-02-01

    Photoperiodic control of flowering time consists of a complicated network that converges into the generation of a mobile flowering signal called florigen. Recent advances identifying the protein FT/Hd3a as the molecular nature responsible for florigen activity have focused current research on florigen genes as the important output of this complex signaling network. Rice is a model system for short-day plants and recent progress in elucidating the flowering network from rice and Arabidopsis, a long-day plant, provides an evolutionarily comparative view of the photoperiodic flowering pathway. This review summarizes photoperiodic flowering control in rice, including the interaction of complex layers of gene networks contributed from evolutionarily unique factors and the regulatory adaptation of conserved factors.

  8. Natural and anthropogenic variations in atmospheric mercury deposition during the Holocene near Quelccaya Ice Cap, Peru

    Science.gov (United States)

    Beal, Samuel A.; Kelly, Meredith A.; Stroup, Justin S.; Jackson, Brian P.; Lowell, Thomas V.; Tapia, Pedro M.

    2014-04-01

    Mercury (Hg) is a toxic metal that is transported globally through the atmosphere. Emissions of Hg from mineral reservoirs and recycling between soil/biomass, oceans, and the atmosphere are fundamental to the global Hg cycle, yet past emissions from anthropogenic and natural sources are not fully constrained. We use a sediment core from Yanacocha, a headwater lake in southeastern Peru, to study the anthropogenic and natural controls on atmospheric Hg deposition during the Holocene. From 12.3 to 3.5 ka, Hg fluxes in the record are relatively constant (mean ± 1σ: 1.4 ± 0.6 µg m-2 a-1). Past Hg deposition does not correlate with changes in regional temperature and precipitation or with most large volcanic events that occurred regionally (~300-400 km from Yanacocha) and globally. In 1450 B.C. (3.4 ka), Hg fluxes abruptly increased and reached the Holocene-maximum flux (6.7 µg m-2 a-1) in 1200 B.C., concurrent with a ~100 year peak in Fe and chalcophile metals (As, Ag, Tl) and the presence of framboidal pyrite. Continuously elevated Hg fluxes from 1200 to 500 B.C. suggest a protracted mining-dust source near Yanacocha that is identical in timing to documented pre-Incan cinnabar mining in central Peru. During Incan and Colonial time (A.D. 1450-1650), Hg deposition remains elevated relative to background levels but lower relative to other Hg records from sediment cores in central Peru, indicating a limited spatial extent of preindustrial Hg emissions. Hg fluxes from A.D. 1980 to 2011 (4.0 ± 1.0 µg m-2 a-1) are 3.0 ± 1.5 times greater than preanthropogenic fluxes.

  9. Natural variation in maternal care and cross-tissue patterns of oxytocin receptor gene methylation in rats.

    Science.gov (United States)

    Beery, Annaliese K; McEwen, Lisa M; MacIsaac, Julia L; Francis, Darlene D; Kobor, Michael S

    2016-01-01

    This article is part of a Special Issue "Parental Care". Since the first report of maternal care effects on DNA methylation in rats, epigenetic modifications of the genome in response to life experience have become the subject of intense focus across many disciplines. Oxytocin receptor expression varies in response to early experience, and both oxytocin signaling and methylation status of the oxytocin receptor gene (Oxtr) in blood have been related to disordered social behavior. It is unknown whether Oxtr DNA methylation varies in response to early life experience, and whether currently employed peripheral measures of Oxtr methylation reflect variation in the brain. We examined the effects of early life rearing experience via natural variation in maternal licking and grooming during the first week of life on behavior, physiology, gene expression, and epigenetic regulation of Oxtr across blood and brain tissues (mononucleocytes, hippocampus, striatum, and hypothalamus). Rats reared by "high" licking-grooming (HL) and "low" licking-grooming (LL) rat dams exhibited differences across study outcomes: LL offspring were more active in behavioral arenas, exhibited lower body mass in adulthood, and showed reduced corticosterone responsivity to a stressor. Oxtr DNA methylation was significantly lower at multiple CpGs in the blood of LL versus HL males, but no differences were found in the brain. Across groups, Oxtr transcript levels in the hypothalamus were associated with reduced corticosterone secretion in response to stress, congruent with the role of oxytocin signaling in this region. Methylation of specific CpGs at a high or low level was consistent across tissues, especially within the brain. However, individual variation in DNA methylation relative to these global patterns was not consistent across tissues. These results suggest that blood Oxtr DNA methylation may reflect early experience of maternal care, and that Oxtr methylation across tissues is highly concordant

  10. Untangling natural seascape variation from marine reserve effects using a landscape approach.

    Directory of Open Access Journals (Sweden)

    Brittany E Huntington

    Full Text Available Distinguishing management effects from the inherent variability in a system is a key consideration in assessing reserve efficacy. Here, we demonstrate how seascape heterogeneity, defined as the spatial configuration and composition of coral reef habitats, can mask our ability to discern reserve effects. We then test the application of a landscape approach, utilizing advances in benthic habitat mapping and GIS techniques, to quantify this heterogeneity and alleviate the confounding influence during reserve assessment. Seascape metrics were quantified at multiple spatial scales using a combination of spatial image analysis and in situ surveys at 87 patch reef sites in Glover's Reef Lagoon, Belize, within and outside a marine reserve enforced since 1998. Patch reef sites were then clustered into classes sharing similar seascape attributes using metrics that correlated significantly to observed variations in both fish and coral communities. When the efficacy of the marine reserve was assessed without including landscape attributes, no reserve effects were detected in the diversity and abundance of fish and coral communities, despite 10 years of management protection. However, grouping sites based on landscape attributes revealed significant reserve effects between site classes. Fish had higher total biomass (1.5x and commercially important biomass (1.75x inside the reserve and coral cover was 1.8 times greater inside the reserve, though direction and degree of response varied by seascape class. Our findings show that the application of a landscape classification approach vastly improves our ability to evaluate the efficacy of marine reserves by controlling for confounding effects of seascape heterogeneity and suggests that landscape heterogeneity should be considered in future reserve design.

  11. Weekly variations of discharge and groundwater quality caused by intermittent water supply in an urbanized karst catchment

    Science.gov (United States)

    Grimmeisen, Felix; Zemann, Moritz; Goeppert, Nadine; Goldscheider, Nico

    2016-06-01

    Leaky sewerage and water distribution networks are an enormous problem throughout the world, specifically in developing countries and regions with water scarcity. Especially in many arid and semi-arid regions, intermittent water supply (IWS) is common practice to cope with water shortage. This study investigates the combined influence of urban activities, IWS and water losses on groundwater quality and discusses the implications for water management. In the city of As-Salt (Jordan), local water supply is mostly based on groundwater from the karst aquifer that underlies the city. Water is delivered to different supply zones for 24, 48 or 60 h each week with drinking water losses of around 50-60%. Fecal contamination in groundwater, mostly originating from the likewise leaky sewer system is a severe challenge for the local water supplier. In order to improve understanding of the local water cycle and contamination dynamics in the aquifer beneath the city, a down gradient spring and an observation well were chosen to identify contaminant occurrence and loads. Nitrate, Escherichia coli, spring discharge and the well water level were monitored for 2 years. Autocorrelation analyses of time series recorded during the dry season revealed weekly periodicity of spring discharge (45 ± 3.9 L s-1) and NO3-N concentrations (11.4 ± 0.8 mg L-1) along with weekly varying E. coli levels partly exceeding 2.420 MPN 100 mL-1. Cross-correlation analyses demonstrate a significant and inverse correlation of nitrate and discharge variations which points to a periodic dilution of contaminated groundwater by freshwater from the leaking IWS being the principal cause of the observed fluctuations. Contaminant inputs from leaking sewers appear to be rather constant. The results reveal the distinct impact of leaking clean IWS on the local groundwater and subsequently on the local water supply and therefore demonstrate the need for action regarding the mitigation of groundwater contamination and

  12. Temporary management of permanent central incisors loss caused by trauma in primary dentition with natural crowns: a case report.

    Science.gov (United States)

    Tüzüner, Tamer; Kuşgöz, Adem; Nur, Bilge Gülsüm

    2009-10-01

    Primary teeth injuries may cause developmental disturbances in the permanent dentition and loss of permanent incisors could be treated with different options. In this case report, an 11-year-old boy, with a history of trauma at the age of 4 years, is presented. Premature loss of permanent upper right central and upper left central teeth because of the mobility and arrest in root development were treated using patient's own natural crowns on a removable appliance. This treatment option could be considered as an esthetic and functional temporary management of permanent central incisors loss until the definitive treatment will be completed in the future.

  13. Natural disease course and genotype-phenotype correlations in Complex I deficiency caused by nuclear gene defects

    DEFF Research Database (Denmark)

    Koene, S; Rodenburg, R J; van der Knaap, M S;

    2012-01-01

    Mitochondrial complex I is the largest multi-protein enzyme complex of the oxidative phosphorylation system. Seven subunits of this complex are encoded by the mitochondrial and the remainder by the nuclear genome. We review the natural disease course and signs and symptoms of 130 patients (four new...... cases and 126 from literature) with mutations in nuclear genes encoding structural complex I proteins or those involved in its assembly. Complex I deficiency caused by a nuclear gene defect is usually a non-dysmorphic syndrome, characterized by severe multi-system organ involvement and a poor prognosis...

  14. Natural genetic variation in selected populations of Arabidopsis thaliana is associated with ionomic differences.

    Directory of Open Access Journals (Sweden)

    Elizabeth Buescher

    Full Text Available Controlling elemental composition is critical for plant growth and development as well as the nutrition of humans who utilize plants for food. Uncovering the genetic architecture underlying mineral ion homeostasis in plants is a critical first step towards understanding the biochemical networks that regulate a plant's elemental composition (ionome. Natural accessions of Arabidopsis thaliana provide a rich source of genetic diversity that leads to phenotypic differences. We analyzed the concentrations of 17 different elements in 12 A. thaliana accessions and three recombinant inbred line (RIL populations grown in several different environments using high-throughput inductively coupled plasma- mass spectroscopy (ICP-MS. Significant differences were detected between the accessions for most elements and we identified over a hundred QTLs for elemental accumulation in the RIL populations. Altering the environment the plants were grown in had a strong effect on the correlations between different elements and the QTLs controlling elemental accumulation. All ionomic data presented is publicly available at www.ionomicshub.org.

  15. Natural variation of magnesium isotopes in mammal bones and teeth from two South African trophic chains

    Science.gov (United States)

    Martin, Jeremy E.; Vance, Derek; Balter, Vincent

    2014-04-01

    Isotopic fractionations accompanying element transfer through terrestrial ecosystems have the potential to shed light on ecological interactions between primary producers and consumers, but with the exception of carbon and nitrogen this potential has barely been exploited. Here, the magnesium stable isotope composition of bones and teeth of extant mammals from Kruger National Park (KNP) and Western Cape (WC), South Africa was measured for the first time. The nature of the geological substrate proves to be a major determinant of the ecosystem isotope baseline, as indicated by the lighter magnesium isotope ratios measured in WC mammals (ranging from -1.58‰ to -0.79‰) compared to those from KNP mammals (ranging from -1.01‰ to -0.04‰). Therefore, comparisons between the isotope signatures of taxa must be restricted to a pre-defined geographic area with a homogeneous substrate. In both parks, Mg shows slight enrichment in heavier isotopes from herbivores to carnivores. Plant remains trapped in the dentition of herbivores provide direct evidence of dietary source and, when available, were measured. In KNP only, δ26Mg of plant remains is systematically lighter than the values for herbivore teeth. These results invite further exploration of the variability of Mg isotopes in vertebrate ecosystems in order to test whether magnesium, a bio-essential element present in relatively large proportions in bone and teeth apatite, may serve as an additional trophic tracer to nitrogen, which is a constituent of collagen that rapidly degrades after burial.

  16. Patterns of Natural and Human-Caused Mortality Factors of a Rare Forest Carnivore, the Fisher (Pekania pennanti in California.

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    Mourad W Gabriel

    Full Text Available Wildlife populations of conservation concern are limited in distribution, population size and persistence by various factors, including mortality. The fisher (Pekania pennanti, a North American mid-sized carnivore whose range in the western Pacific United States has retracted considerably in the past century, was proposed for threatened status protection in late 2014 under the United States Endangered Species Act by the United States Fish and Wildlife Service in its West Coast Distinct Population Segment. We investigated mortality in 167 fishers from two genetically and geographically distinct sub-populations in California within this West Coast Distinct Population Segment using a combination of gross necropsy, histology, toxicology and molecular methods. Overall, predation (70%, natural disease (16%, toxicant poisoning (10% and, less commonly, vehicular strike (2% and other anthropogenic causes (2% were causes of mortality observed. We documented both an increase in mortality to (57% increase and exposure (6% from pesticides in fishers in just the past three years, highlighting further that toxicants from marijuana cultivation still pose a threat. Additionally, exposure to multiple rodenticides significantly increased the likelihood of mortality from rodenticide poisoning. Poisoning was significantly more common in male than female fishers and was 7 times more likely than disease to kill males. Based on necropsy findings, suspected causes of mortality based on field evidence alone tended to underestimate the frequency of disease-related mortalities. This study is the first comprehensive investigation of mortality causes of fishers and provides essential information to assist in the conservation of this species.

  17. Tracking Down the Causes of Recent Induced and Natural Intraplate Earthquakes with 3D Seismological Analyses in Northwest Germany

    Science.gov (United States)

    Uta, P.; Brandes, C.; Boennemann, C.; Plenefisch, T.; Winsemann, J.

    2015-12-01

    Northwest Germany is a typical low strain intraplate region with a low seismic activity. Nevertheless, 58 well documented earthquakes with magnitudes of 0.5 - 4.3 affected the area in the last 40 years. Most of the epicenters were located in the vicinity of active natural gas fields and some inside. Accordingly, the earthquakes were interpreted as a consequence of hydrocarbon recovery (e.g. Dahm et al. 2007, Bischoff et al. 2013) and classified as induced events in the bulletins of the Federal Institute for Geosciences and Natural Resources (BGR). The two major ones have magnitudes of 4.3 and 4.0. They are the strongest earthquakes ever recorded in Northern Germany. Consequently, these events raise the question whether the ongoing extraction itself can cause them or if other natural tectonic processes like glacial isostatic adjustment may considerably contribute to their initiation. Recent studies of Brandes et al. (2012) imply that lithospheric stress changes due to post glacial isostatic adjustment might be also a potential natural cause for earthquakes in Central Europe. In order to better analyse the earthquakes and to test this latter hypothesis we performed a relocalization of the events with the NonLinLoc (Lomax et al. 2000) program package and two differently scaled 3D P-wave velocity models. Depending on the station coverage for a distinct event, either a fine gridded local model (88 x 73 x 15 km, WEG-model, made available by the industry) or a coarse regional model (1600 x 1600 x 45 km, data from CRUST1.0, Laske et al. 2013) and for some cases a combination of both models was used for the relocalization. The results confirm the trend of the older routine analysis: The majority of the events are located at the margins of the natural gas fields, some of them are now located closer to them. Focal depths mostly vary between 3.5 km and 10 km. However, for some of the events, especially for the older events with relatively bad station coverage, the error bars

  18. A need for orientation: The WMA statement on natural variations of human sexuality.

    Science.gov (United States)

    Mahler, Lieselotte; Mundle, Goetz

    2015-01-01

    An alarming stigmatization and discrimination of homosexual people persists despite the formal depathologization of homosexuality, which occurred through the removal of the diagnosis from the DSM- (1973) and classification from the ICD (1991). The adoption of an expedited Statement on sexual orientation by the majority at the 64th General Assembly of the WMA is therefore an important and overdue measure. The Statement clearly asserts, among other things, that homosexuality is not an illness and therefore requires no cure. It also suggests that direct and indirect discrimination and stigmatization of people due their sexual orientation often leads to psychological and physical illnesses. Furthermore, delegates of the WMA condemned so-called reparative or conversion "therapies", which strive to induce heterosexual or asexual behavior. These are not only ineffective and unethical, but are strongly associated with serious negative impacts on health. Such a statement from the World Medical Association (WMA) is of particular importance as ambivalence and uncertainty in regards to homosexuality exists even within the medical and therapeutic professions. The latent or manifest attribution of homosexuality as an illness or developmental disorder is still widespread. One possible explanation for this may be the disruption of an open and sustainable discourse on causes, effects and definitions of sexual orientation following the "official depathologization". Especially those working in the medical and therapeutic contexts should be aware of their special responsibility not to pathologize homosexuality.

  19. Intraspecies variation in the emergence of hyperinfectious bacterial strains in nature.

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    Douglas M Heithoff

    Full Text Available Salmonella is a principal health concern because of its endemic prevalence in food and water supplies, the rise in incidence of multi-drug resistant strains, and the emergence of new strains associated with increased disease severity. Insights into pathogen emergence have come from animal-passage studies wherein virulence is often increased during infection. However, these studies did not address the prospect that a select subset of strains undergo a pronounced increase in virulence during the infective process- a prospect that has significant implications for human and animal health. Our findings indicate that the capacity to become hypervirulent (100-fold decreased LD(50 was much more evident in certain S. enterica strains than others. Hyperinfectious salmonellae were among the most virulent of this species; restricted to certain serotypes; and more capable of killing vaccinated animals. Such strains exhibited rapid (and rapidly reversible switching to a less-virulent state accompanied by more competitive growth ex vivo that may contribute to maintenance in nature. The hypervirulent phenotype was associated with increased microbial pathogenicity (colonization; cytotoxin production; cytocidal activity, coupled with an altered innate immune cytokine response within infected cells (IFN-β; IL-1β; IL-6; IL-10. Gene expression analysis revealed that hyperinfectious strains display altered transcription of genes within the PhoP/PhoQ, PhoR/PhoB and ArgR regulons, conferring changes in the expression of classical virulence functions (e.g., SPI-1; SPI-2 effectors and those involved in cellular physiology/metabolism (nutrient/acid stress. As hyperinfectious strains pose a potential risk to human and animal health, efforts toward mitigation of these potential food-borne contaminants may avert negative public health impacts and industry-associated losses.

  20. Topographic monitoring of a middle estuary mudflat, Humber estuary, UK--anthropogenic impacts and natural variation.

    Science.gov (United States)

    Boyes, Suzanne J; Allen, James H

    2007-01-01

    Annual topographic surveys were carried out at the Saltend mudflat (Humber estuary, UK) between 1998 and 2006. These surveys formed part of an ongoing monitoring programme to examine the potential effects on the mudflat topography of the construction and operation of a waste water treatment works (WwTW) development by Yorkshire Water. Of particular concern was the potential disruption to the sedimentological regime within the special protection area (SPA) and candidate special area of conservation (cSAC) which could affect the invertebrate communities and ornithological functioning of the site. In addition to the development of the WwTW located to the extreme north-west of the site, a port extension removing 10ha of the Saltend intertidal mudflat (outside the SPA but immediately south east of the WwTW) also occurred between 1999 and 2006. Minimal change was noted across the site following the construction and operation of the WwTW between 1998 and 2000. However, the construction of the bund in closer proximity to the SPA and cSAC masked any potential impact the WwTW could have had across the site after 2000. Profiles and contour mapping indicate that significant mudflat accretion occurred in the immediate area of the bund, with a general increase recorded across the western section of the site since 2000. In contrast the alternations to channel planform and subsequent rapid accretion of the mudflat to the east of the jetty, being a significant distance from the developments, are attributed to natural cyclical changes.

  1. Regional variation in the biogeochemical and physical characteristics of natural peatland pools.

    Science.gov (United States)

    Turner, T Edward; Billett, Michael F; Baird, Andy J; Chapman, Pippa J; Dinsmore, Kerry J; Holden, Joseph

    2016-03-01

    Natural open-water pools are a common feature of northern peatlands and are known to be an important source of atmospheric methane (CH4). Pool environmental variables, particularly water chemistry, vegetation community and physical characteristics, have the potential to exert strong controls on carbon cycling in pools. A total of 66 peatland pools were studied across three regions of the UK (northern Scotland, south-west Scotland, and Northern Ireland). We found that within-region variability of pool water chemistry was low; however, for many pool variables measured there were significant differences between regions. PCA analysis showed that pools in SW Scotland were strongly associated with greater vegetative cover and shallower water depth which is likely to increase dissolved organic carbon (DOC) mineralisation rates, whereas pools in N Scotland were more open and deeper. Pool water DOC, particulate organic carbon and dissolved CH4 concentrations were significantly different between regions. Pools in Northern Ireland had the highest concentrations of DOC (mean=14.5 mg L(-1)) and CH4 (mean=20.6 μg C L(-1)). Chloride and sulphate concentrations were significantly higher in the pools in N Scotland (mean values 26.3 and 2.40 mg L(-1), respectively) than elsewhere, due to a stronger marine influence. The ratio of UV absorbance at 465 nm to absorbance at 665 nm for pools in Northern Ireland indicated that DOC was sourced from poorly humified peat, potentially increasing the bioavailability and mineralisation of organic carbon in pools compared to the pools elsewhere. This study, which specifically aims to address a lack of basic biogeochemical knowledge about pool water chemistry, clearly shows that peatland pools are highly regionally variable. This is likely to be a reflection of significant regional-scale differences in peatland C cycling.

  2. Seasonal, synoptic and diurnal variation of atmospheric water-isotopologues in the boundary layer of Southwestern Germany caused by plant transpiration, cold-front passages and dewfall.

    Science.gov (United States)

    Christner, Emanuel; Dyroff, Christoph; Kohler, Martin; Zahn, Andreas; Gonzales, Yenny; Schneider, Matthias

    2013-04-01

    Atmospheric water is an enormously crucial trace gas. It is responsible for ~70 % of the natural greenhouse effect (Schmidt et al., JGR, 2010) and carries huge amounts of latent heat. The isotopic composition of water vapor is an elegant tracer for a better understanding and quantification of the extremely complex and variable hydrological cycle in Earth's atmosphere (evaporation, cloud condensation, rainout, re-evaporation, snow), which in turn is a prerequisite to improve climate modeling and predictions. As H216O, H218O and HDO differ in vapor pressure and mass, isotope fractionation occurs due to condensation, evaporation and diffusion processes. In contrast to that, plants are able to transpire water with almost no isotope fractionation. For that reason the ratio of isotopologue concentrations in the boundary layer (BL) provides, compared to humidity measurements alone, independent and additional constraints for quantifying the strength of evaporation and transpiration. Furthermore the isotope ratios contain information about transport history of an air mass and microphysical processes, that is not accessible by humidity measurements. Within the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) a commercial Picarro Analyzer L2120-i is operated at Karlsruhe in Southwestern Germany, which is continuously measuring the isotopologues H216O, HDO and H218O of atmospheric water vapor since January 2012. A one year record of H216O, HDO and H218O shows clear seasonal, synoptic and diurnal characteristics and reveals the main driving processes affecting the isotopic composition of water vapor in the Middle European BL. Changes in continental plant transpiration and evaporation throughout the year lead to a slow seasonal HDO/H216O-variation, that cannot be explained by pure Rayleigh condensation. Furthermore, cold-front passages from NW lead to fast and pronounced depletion of the HDO/H216O-ratio within

  3. Groundwater capture processes under a seasonal variation in natural recharge and discharge

    Science.gov (United States)

    Maddock, Thomas, III.; Vionnet, Leticia Beatriz

    "Capture" is the increase in recharge and the decrease in discharge that occurs when pumping is imposed on an aquifer system that was in a previous state of approximate dynamic equilibrium. Regional groundwater models are usually used to calculate capture in a two-step procedure. A steady-state solution provides an initial-head configuration, a set of flows through the boundaries for the modeled region, and the initial basis for the capture calculation. The transient solutions provide the total change in flows through the boundaries. A difference between the transient and steady-state solutions renders the capture calculation. When seasonality is a modeling issue, the use of a single initial hydraulic head and a single set of boundary flows leads to miscalculations of capture. Instead, an initial condition for each season should be used. This approach may be accomplished by determining steady oscillatory solutions, which vary through the seasons but repeat from year to year. A regional groundwater model previously developed for a portion of the San Pedro River basin, Arizona, USA, is modified to illustrate the effect that different initial conditions have on transient solutions and on capture calculations. Résumé Les "prélèvements" sont constitués par l'augmentation de la recharge et par la diminution de l'écoulement qui se produit lorsqu'un pompage est imposéà un système aquifère qui était auparavant dans un état proche de l'équilibre dynamique. Les modèles régionaux de nappe sont en général utilisés pour calculer les prélèvements dans une procédure à deux étapes. Une solution en régime permanent donne la configuration piézométrique initiale, un jeu de conditions aux limites pour la région modélisée et les données de base pour le calcul des prélèvements. Les solutions transitoires donnent les modifications globales des conditions aux limites. Lorsque des variations saisonnières sont produites en sortie du modèle, le recours à une

  4. The Gravity Field Variation Caused by Inner Core Super Rotation%内核超速旋转引起的重力场变化

    Institute of Scientific and Technical Information of China (English)

    陈巍; 申文斌; 韩建成

    2008-01-01

    Due to the super rotation of the Earth's inner core,the tilted figure axis of the inner core would progress with re-spect to the mantle and thus cause the variation of the Earth's external gravity field.This paper improves the present model of the gravity field variation caused by the inner core super rotation.Under the assumption that the inner core is a stratifying ellipsoid whose density function is fitted out from PREM and the super rotation rate is 0.27~0.53°/yr,calculations show that the global temporal variations on the Earth's surface have a maximum value of about 0.79~1.54×103 μGal and a global av-erage intensity of about 0.45~0.89×103 μGal in the whole year of 2007,which is beyond the accuracy of the present gra-vimetry and even the super conducting gravimeter data.However,both the gravity variations at Beijing and Wuhan vary like sine variables with maximal variations around 0.33 μGal and 0.29 μGal,respectively,in one cycle.Thus,continuous gravity measurements for one or two decades might be able to detect the differential motion of the inner core.

  5. What can long-lived mutants tell us about mechanisms causing aging and lifespan variation in natural environments?

    NARCIS (Netherlands)

    Briga, Michael; Verhulst, Simon

    2015-01-01

    Long-lived mutants of model organisms have brought remarkable progress in our understanding of aging mechanisms. However, long-lived mutants are usually maintained in optimal standardized laboratory environments (SLEs), and it is not obvious to what extent insights from long-lived mutants in SLEs ca

  6. Variations in mitochondrial membrane potential correlate with malic acid production by natural isolates of Saccharomyces cerevisiae sake strains.

    Science.gov (United States)

    Oba, Takahiro; Kusumoto, Kenichi; Kichise, Yuki; Izumoto, Eiji; Nakayama, Shunichi; Tashiro, Kosuke; Kuhara, Satoru; Kitagaki, Hiroshi

    2014-08-01

    Research on the relationship between mitochondrial membrane potential and fermentation profile is being intensely pursued because of the potential for developing advanced fermentation technologies. In the present study, we isolated naturally occurring strains of yeast from sake mash that produce high levels of malic acid and demonstrate that variations in mitochondrial membrane potential correlate with malic acid production. To define the underlying biochemical mechanism, we determined the activities of enzymes required for malic acid synthesis and found that pyruvate carboxylase and malate dehydrogenase activities in strains that produce high levels of malic acid were elevated compared with the standard sake strain K901. These results inspired us to hypothesize that decreased mitochondrial membrane potential was responsible for increased malic acid synthesis, and we present data supporting this hypothesis. Thus, the mitochondrial membrane potential of high malic acid producers was lower compared with standard strains. We conclude that mitochondrial membrane potential correlates with malic acid production.

  7. Seasonal variations of natural ventilation and radon-222 exhalation in a slightly rising dead-end tunnel.

    Science.gov (United States)

    Perrier, Frédéric; Richon, Patrick; Gautam, Umesh; Tiwari, Dilli Ram; Shrestha, Prithvi; Sapkota, Soma Nath

    2007-01-01

    The concentration activity of radon-222 has been monitored, with some interruptions, from 1997 to 2005 in the end section of a slightly rising, dead-end, 38-m long tunnel located in the Phulchoki hill, near Kathmandu, Nepal. While a high concentration varying from 6 x 10(3) Bq m(-3) to 10 x 10(3) Bq m(-3) is observed from May to September (rainy summer season), the concentration remains at a low level of about 200 Bq m(-3) from October to March (dry winter season). This reduction of radon concentration is associated with natural ventilation of the tunnel, which, contrary to expectations for a rising tunnel, takes place mainly from October to March when the outside air temperature drops below the average tunnel temperature. This interpretation is supported by temperature measurements in the atmosphere of the tunnel, a few meters away from the entrance. The temporal variations of the diurnal amplitude of this temperature indeed follow the ventilation rate deduced from the radon measurements. In the absence of significant ventilation (summer season), the radon exhalation flux at the rock surface into the tunnel atmosphere can be inferred; it exhibits a yearly variation with additional transient reductions associated with heavy rainfall, likely to be due to water infiltration. No effect of atmospheric pressure variations on the radon concentration is observed in this tunnel. This experiment illustrates how small differences in the location and geometry of a tunnel can lead to vastly different behaviours of the radon concentration versus time. This observation has consequences for the estimation of the dose rate and the practicability of radon monitoring for tectonic purposes in underground environments.

  8. Patterns of variation in levels of hsp70 in natural rocky shore populations from microscales to mesoscales.

    Science.gov (United States)

    Halpin, Patricia M; Sorte, Cascade J; Hofmann, Gretchen E; Menge, Bruce A

    2002-08-01

    An important step in connecting the organismal response to thermal stress to patterns of community structure is determining at what scale discernable levels of variation are manifested. The temperature signal to which organisms may potentially respond varies at many spatial scales including microhabitat, tidal height, site and latitude. A number of studies have taken physiological assessment of the heat shock response (HSR) into the intertidal both as a tool for examining the HSR in nature and for examining the utility of HSR molecules as population or community level indicators. Most commonly, immunodetection of the total pool of the Hsp70 family of isoforms is used. Here we present data on levels of Hsp70 in intertidal organisms from microhabitat to the mesoscale. Our data and previously published work show that Hsp70 levels vary at all scales examined, similar to other physical and biological variables of interest. This demonstrates both the potential utility of Hsp70 detection as a molecular tool for field biologists and to the care that must be taken in assessing scale of variation when looking for potential bioindicator molecules.

  9. Natural variation in the Pto disease resistance gene within species of wild tomato (Lycopersicon). II. Population genetics of Pto.

    Science.gov (United States)

    Rose, Laura E; Michelmore, Richard W; Langley, Charles H

    2007-03-01

    Disease resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) in the host species Lycopersicon esculentum, the cultivated tomato, and the closely related L. pimpinellifolium is triggered by the physical interaction between the protein products of the host resistance (R) gene Pto and the pathogen avirulence genes AvrPto and AvrPtoB. Sequence variation at the Pto locus was surveyed in natural populations of seven species of Lycopersicon to test hypotheses of host-parasite coevolution and functional adaptation of the Pto gene. Pto shows significantly higher nonsynonymous polymorphism than 14 other non-R-gene loci in the same samples of Lycopersicon species, while showing no difference in synonymous polymorphism, suggesting that the maintenance of amino acid polymorphism at this locus is mediated by pathogen selection. Also, a larger proportion of ancestral variation is maintained at Pto as compared to these non-R-gene loci. The frequency spectrum of amino acid polymorphisms known to negatively affect Pto function is skewed toward low frequency compared to amino acid polymorphisms that do not affect function or silent polymorphisms. Therefore, the evolution of Pto appears to be influenced by a mixture of both purifying and balancing selection.

  10. Common variation in oxidative phosphorylation genes is not a major cause of insulin resistance or type 2 diabetes

    DEFF Research Database (Denmark)

    Snogdal, L S; Wod, M; Grarup, Niels;

    2012-01-01

    There is substantial evidence that mitochondrial dysfunction is linked to insulin resistance and is present in several tissues relevant to the pathogenesis of type 2 diabetes. Here, we examined whether common variation in genes involved in oxidative phosphorylation (OxPhos) contributes to type 2...... diabetes susceptibility or influences diabetes-related metabolic traits....

  11. Economics of Scholarly Publishing: Exploring the Causes of Subscription Price Variations of Scholarly Journals in Business Subject-Specific Areas

    Science.gov (United States)

    Liu, Lewis G.

    2011-01-01

    This empirical research investigates subscription price variations of scholarly journals in five business subject-specific areas using the semilogarithmic regression model. It has two main purposes. The first is to address the unsettled debate over whether or not and to what extent commercial publishers reap monopoly profits by overcharging…

  12. Moderate intensity supine exercise causes decreased cardiac volumes and increased outer volume variations: a cardiovascular magnetic resonance study

    DEFF Research Database (Denmark)

    Steding-Ehrenborg, Katarina; Jablonowski, Robert; Arvidsson, Per M;

    2013-01-01

    The effects on left and right ventricular (LV, RV) volumes during physical exercise remains controversial. Furthermore, no previous study has investigated the effects of exercise on longitudinal contribution to stroke volume (SV) and the outer volume variation of the heart. The aim of this study...

  13. Natural variation in 210Po and 210Pb activity concentrations in the urine of Finnish population groups.

    Science.gov (United States)

    Muikku, Maarit; Heikkinen, Tarja; Solatie, Dina; Vesterbacka, Pia

    2011-11-01

    A study to determine activity concentrations of (210)Pb and (210)Po in the urine of certain Finnish population groups was conducted, to investigate the variation in natural background level of urinary excretion. The study participants were divided into three groups mainly based on their diet. The first group comprised recreational fishermen and the second group represented people consuming more reindeer meat than an average Finn, while people using drinking water with very high activity concentrations of (210)Po were selected for the third group. The fourth group was a control group. The mean urinary excretion of (210)Po in groups 1 and 2 was 73 and 100 mBq d(-1), respectively. These values were higher than the value of the control group (20 mBq d(-1)) and the mean values reported in the literature. The mean daily urinary excretion of (210)Pb in groups 1 and 2, 70 and 52 mBq d(-1), was also slightly higher than that in the control group (32 mBq d(-1)). In contrast, the excretion rates of both (210)Po and (210)Pb for the members of group 3 were one to two orders of magnitude higher than those reported in the literature. This was clearly due to the elevated levels of natural radionuclides in their drinking water. The present study demonstrates the importance of possessing good knowledge of the background levels, in order to allow the determination of the additional exposure due, for example, to the malevolent use of radiation.

  14. SPATIAL VARIATION OF Zn GEOCHEMICAL FRACTIONS IN THE SURFACE SEDIMENTS OF THE STRAITS OF MALACCA: NATURAL OR ANTHROPOGENIC?

    Institute of Scientific and Technical Information of China (English)

    Chee Kong Yap; Ahmad Ismail; Soon Guan Tan

    2005-01-01

    Total concentrations of Zn in the sediments of the offshore and intertidal areas of the west coast of Peninsular Malaysia were recently reported in the literaturs. However, total concentrations of metals in the sediment samples do not reflect the portion or carrier phase which is attributable to anthropogenic activities and those of natural origins.In this work, geochemical fraction of Zn in the sediments of the same areas was studied and the potential use of CV as an indicator of Zn pollution was determined. The geochemical study by using sequential extraction technique revealed tions, respectively, in the sediments while most of the total zinc concentrations (offshore: 70%; intertidal: 52%)found in the sediments could be mostly due to natural origins (nonresistant fraction). Thus, the Zn levels in the Straits of Malacca should not pose a risk to the liying organisms. Based on Spearman's correlation coefficients, the source of Zn contamination in the Straits of Malacca was mainly contributed by the intertidal coastal area rather than offshore area. The present study also indicated the coefficient of variation can be used as a potential indicator of total summation of geochemical Zn concentrations in the coastal sediment but of different geochemical of Zn needs further validation.

  15. Variation of mechanical and thermal properties of the thermoplastics reinforced with natural fibers by electron beam processing

    Science.gov (United States)

    Kim, Sok Won; Oh, Seungmin; Lee, Kyuse

    2007-11-01

    With restrictions for environmental protection being strengthened, the thermoplastics reinforced with natural fibers (NFs) such as jute, kenaf, flax, etc., appeared as an automobile interior material instead of the chemical plastics. Regardless of many advantages, one shortcoming is the deformation after being formed in high temperature of about 200 °C, caused by the poor adhesion between the natural fibers and thermoplastics. Also, the energy saving in connection with car air-conditioning becomes very important. In this study, the thermal conductivity, tensile strength, and deformation of several kinds of thermoplastic composites composing of 50% polypropylene (PP) and 50% natural fiber irradiated by the electron beam (energy: 0.5 MeV, dose: 0-20 kGy) were measured. The length and thickness of PP and NF are 80±10 mm and 40-120 μm, respectively. The results show that the thermal conductivity and the tensile strength changed and became minimum when the dose of electron beam is 10 kGy, and the deformation after the thermal cycle were reduced by the electron beam.

  16. Nature and causes of protracted droughts in southeast Australia: Comparison between the Federation, WWII, and Big Dry droughts

    Science.gov (United States)

    Verdon-Kidd, Danielle C.; Kiem, Anthony S.

    2009-11-01

    Three protracted droughts have occurred during the instrumental history of Southeast Australia (SEA) - the “Federation” (˜1895-1902), “World War II” (˜1937-1945) and the “Big Dry” (˜1997-present). This paper compares the nature and causes of these droughts in order to better inform drought management strategies in SEA. It is shown that the three droughts differ in terms of severity, spatial footprint, seasonality and seasonal rainfall make-up. This diversity arises due to the fact that the droughts are driven by different climatic teleconnections with the Pacific, Indian and Southern Oceans. Importantly, this study highlights potential flaws with drought forecasting and management in SEA and emphasises the need for further research into understanding and representing hydroclimatic drivers of drought.

  17. Understanding the Causes and Implications of Endothelial Metabolic Variation in Cardiovascular Disease through Genome-Scale Metabolic Modeling

    DEFF Research Database (Denmark)

    McGarrity, Sarah; Halldórsson, Haraldur; Palsson, Sirus

    2016-01-01

    of endothelial cell (EC) metabolism and its connections to cardiovascular disease (CVD) and explore the use of genome-scale metabolic models (GEMs) for integrating metabolic and genomic data. GEMs combine gene expression and metabolic data acting as frameworks for their analysis and, ultimately, afford...... mechanistic understanding of how genetic variation impacts metabolism. We demonstrate how GEMs can be used to investigate CVD-related genetic variation, drug resistance mechanisms, and novel metabolic pathways in ECs. The application of GEMs in personalized medicine is also highlighted. Particularly, we focus...... on the potential of GEMs to identify metabolic biomarkers of endothelial dysfunction and to discover methods of stratifying treatments for CVDs based on individual genetic markers. Recent advances in systems biology methodology, and how these methodologies can be applied to understand EC metabolism in both health...

  18. The long-term trend in the diurnal temperature range over Asia and its natural and anthropogenic causes

    Science.gov (United States)

    Liu, Lin; Li, Zhanqing; Yang, Xin; Gong, Hainan; Li, Chao; Xiong, Anyuan

    2016-04-01

    Understanding the causes of long-term temperature trends is at the core of climate change studies. Any observed trend can result from natural variability or anthropogenic influences or both. In the present study, we evaluated the performance of 18 climate models from the Coupled Model Intercomparison Project Phase 5 on simulating the Asian diurnal temperature range (DTR) and explored the potential causes of the long-term trend in the DTR by examining the response of the DTR to natural forcing (volcanic aerosols and solar variability) and anthropogenic forcing (anthropogenic greenhouse gases (GHG) and aerosols) in the historical period of 1961-2005. For the climatology, the multimodel ensemble mean reproduced the geographical distribution and amplitude of the DTR over eastern China and India but underestimated the magnitudes of the DTR over the Tibetan Plateau and the high-latitude regions of the Asian continent. These negative biases in the DTR over frigid zones existed in most models. Seasonal biases in the DTR pattern from models were similar to the bias in the annual mean DTR pattern. Based on three selected state-of-the-art models, the observed decreasing trend in the DTR over Asia was reasonably reproduced in the all-forcing run. A comparison of separate forcing experiments revealed that anthropogenic forcing plays the dominant role in the declining trend in the DTR. Observations and model simulations showed that GHG forcing is mainly responsible for the negative trends in the DTR over Asia but that anthropogenic aerosol forcing was also behind the decreasing trend in the DTR over China and especially over eastern China.

  19. LONG-TERM VARIATION IN THE SUN’S ACTIVITY CAUSED BY MAGNETIC ROSSBY WAVES IN THE TACHOCLINE

    Energy Technology Data Exchange (ETDEWEB)

    Zaqarashvili, Teimuraz V. [Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz (Austria); Oliver, Ramon; Ballester, Jose Luis [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Hanslmeier, Arnold [Institute für Physik, Geophysik Astrophysik und Meteorologie, University of Graz, Univ.-Platz 5, 8010 Graz (Austria); Carbonell, Marc [Departament de Matemàtiques i Informàtica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Gachechiladze, Tamar [Abastumani Astrophysical Observatory at Ilia State University, Tbilisi, Georgia (United States); Usoskin, Ilya G., E-mail: teimuraz.zaqarashvili@oeaw.ac.at [Sodankylä Geophysical Observatory and ReSoLVE Centre of Excellence, University of Oulu, FI-90014 Oulo (Finland)

    2015-06-01

    Long-term records of sunspot number and concentrations of cosmogenic radionuclides (10Be and 14C) on the Earth reveal the variation of the Sun's magnetic activity over hundreds and thousands of years. We identify several clear periods in sunspot, 10Be, and 14C data as 1000, 500, 350, 200, and 100 years. We found that the periods of the first five spherical harmonics of the slow magnetic Rossby mode in the presence of a steady toroidal magnetic field of 1200–1300 G in the lower tachocline are in perfect agreement with the timescales of observed variations. The steady toroidal magnetic field can be generated in the lower tachocline either due to the steady dynamo magnetic field for low magnetic diffusivity or due to the action of the latitudinal differential rotation on the weak poloidal primordial magnetic field, which penetrates from the radiative interior. The slow magnetic Rossby waves lead to variations of the steady toroidal magnetic field in the lower tachocline, which modulate the dynamo magnetic field and consequently the solar cycle strength. This result constitutes a key point for long-term prediction of the cycle strength. According to our model, the next deep minimum in solar activity is expected during the first half of this century.

  20. Altered cardiac bradykinin metabolism in experimental diabetes caused by the variations of angiotensin-converting enzyme and other peptidases.

    Science.gov (United States)

    Adam, Albert; Leclair, Patrick; Montpas, Nicolas; Koumbadinga, Gérémy Abdull; Bachelard, Hélène; Marceau, François

    2010-04-01

    The peptidases angiotensin-converting enzyme (ACE) and neutral endopeptidase 24.11 (NEP) mediate most of the kinin catabolism in normal cardiac tissue and are the molecular targets of inhibitory drugs that favorably influence diabetic complications. We studied the variations of those kininases in the myocardium of rats in experimental diabetes. ACE and NEP activities were significantly decreased in heart membranes 4-8weeks post-streptozotocin (STZ) injection. However, insulin-dependent diabetes did not modify significantly bradykinin (BK) half-life (t(1/2)) while the effect of both ACE (enalaprilat) and ACE and NEP (omapatrilat) inhibitors on BK degradation progressively decreased, which may be explained by the upregulation of other unidentified metallopeptidase(s). In vivo insulin treatment restored the activities of both ACE and NEP. ACE and NEP activities were significantly higher in hearts of young Zucker rats than in those of Sprague-Dawley rats. BK t(1/2) and the effects of peptidase inhibitors on t(1/2) varied accordingly. It is concluded that kininase activities are subjected to large and opposite variations in rat cardiac tissue in type I and II diabetes models. A number of tissue or molecular factors may determine these variations, such as remodeling of cardiac tissue, ectoenzyme shedding to the extracellular fluid and the pathologic regulation of peptidase gene expression.

  1. Gravitational and magnetic field variations synergize to cause subtle variations in the global transcriptional state of Arabidopsis in vitro callus cultures

    Directory of Open Access Journals (Sweden)

    Manzano Ana I

    2012-03-01

    Full Text Available Abstract Background Biological systems respond to changes in both the Earth's magnetic and gravitational fields, but as experiments in space are expensive and infrequent, Earth-based simulation techniques are required. A high gradient magnetic field can be used to levitate biological material, thereby simulating microgravity and can also create environments with a reduced or an enhanced level of gravity (g, although special attention should be paid to the possible effects of the magnetic field (B itself. Results Using diamagnetic levitation, we exposed Arabidopsis thaliana in vitro callus cultures to five environments with different levels of effective gravity and magnetic field strengths. The environments included levitation, i.e. simulated μg* (close to 0 g* at B = 10.1 T, intermediate g* (0.1 g* at B = 14.7 T and enhanced gravity levels (1.9 g* at B = 14.7 T and 2 g* at B = 10.1 T plus an internal 1 g* control (B = 16.5 T. The asterisk denotes the presence of the background magnetic field, as opposed to the effective gravity environments in the absence of an applied magnetic field, created using a Random Position Machine (simulated μg and a Large Diameter Centrifuge (2 g. Microarray analysis indicates that changes in the overall gene expression of cultured cells exposed to these unusual environments barely reach significance using an FDR algorithm. However, it was found that gravitational and magnetic fields produce synergistic variations in the steady state of the transcriptional profile of plants. Transcriptomic results confirm that high gradient magnetic fields (i.e. to create μg* and 2 g* conditions have a significant effect, mainly on structural, abiotic stress genes and secondary metabolism genes, but these subtle gravitational effects are only observable using clustering methodologies. Conclusions A detailed microarray dataset analysis, based on clustering of similarly expressed genes (GEDI software, can detect underlying global

  2. Prevalence, Development, and Significance of Ascochyta Blight Caused by Peyronellaea pinodes in Pisum elatius Populations Growing in Natural Ecosystems.

    Science.gov (United States)

    Golani, M; Frenkel, O; Bornstein, M; Shulhani, R; Abbo, S; Shtienberg, D

    2016-08-01

    Wild Pisum populations prevail in Israel in regions with diverse climatic conditions. A comprehensive survey was conducted in the winters of 2007-08 and 2008-09 at two sites in northern Israel, aiming to (i) document the density of Pisum elatius plants in natural ecosystems and elucidate factors related to their initial infection by Ascochyta blight and (ii) determine the factors governing disease development over time on individual plants. The surveyors identified P. elatius plants growing in designated quadrats, inspected each plant visually, and recorded the incidence and severity of its Ascochyta blight symptoms. Ascochyta blight, caused by Peyronellaea pinodes, was ubiquitous in Pisum elatius populations at both survey sites in both seasons. However, the total leaf area exhibiting disease symptoms of individual plants was very low, and stem and pod infections were rarely observed. Based on analyses of the survey data, it was suggested that, in natural ecosystems, the teleomorph stage of Peyronellaea pinodes serves as the main source of the primary and the secondary inoculum of the disease. In addition, it was found that infected leaves dropped off soon after infection, thereby precluding development of stem lesions. The plants continued growing and did not die; thus, they overcame the disease and could be considered "cured". This phenomenon was examined and confirmed in artificially inoculated, potted-plant experiments. It would be worthwhile to exploit the potential of this unique resistance mechanism as a tool for Ascochyta blight management in pea breeding.

  3. The causes and circumstances of drinking water incidents impact consumer behaviour: Comparison of a routine versus a natural disaster incident.

    Science.gov (United States)

    Rundblad, Gabriella; Knapton, Olivia; Hunter, Paul R

    2014-11-18

    When public health is endangered, the general public can only protect themselves if timely messages are received and understood. Previous research has shown that the cause of threats to public health can affect risk perception and behaviours. This study compares compliance to public health advice and consumer behaviour during two "Boil Water" notices issued in the UK due to a routine incident versus a natural disaster incident. A postal questionnaire was sent to 1000 randomly selected households issued a routine "Boil Water" notice. Findings were then compared to a previous study that explored drinking water behaviour during a "Boil Water" notice issued after serious floods. Consumers affected by the routine incident showed a significant preference for official water company information, whereas consumers affected by the natural disaster preferred local information sources. Confusion over which notice was in place was found for both incidents. Non-compliance was significantly higher for the natural disaster (48.3%) than the routine incident (35.4%). For the routine incident, compliance with advice on drinking as well as preparing/cooking food and brushing teeth was positively associated with receiving advice from the local radio, while the opposite was true for those receiving advice from the water company/leaflet through the post; we suggest this may largely be due to confusion over needing boiled tap water for brushing teeth. No associations were found for demographic factors. We conclude that information dissemination plans should be tailored to the circumstances under which the advice is issued. Water companies should seek to educate the general public about water notices and which actions are safe and unsafe during which notice, as well as construct and disseminate clearer advice on brushing teeth and preparing/cooking food.

  4. The Causes and Circumstances of Drinking Water Incidents Impact Consumer Behaviour: Comparison of a Routine versus a Natural Disaster Incident

    Directory of Open Access Journals (Sweden)

    Gabriella Rundblad

    2014-11-01

    Full Text Available When public health is endangered, the general public can only protect themselves if timely messages are received and understood. Previous research has shown that the cause of threats to public health can affect risk perception and behaviours. This study compares compliance to public health advice and consumer behaviour during two “Boil Water” notices issued in the UK due to a routine incident versus a natural disaster incident. A postal questionnaire was sent to 1000 randomly selected households issued a routine “Boil Water” notice. Findings were then compared to a previous study that explored drinking water behaviour during a “Boil Water” notice issued after serious floods. Consumers affected by the routine incident showed a significant preference for official water company information, whereas consumers affected by the natural disaster preferred local information sources. Confusion over which notice was in place was found for both incidents. Non-compliance was significantly higher for the natural disaster (48.3% than the routine incident (35.4%. For the routine incident, compliance with advice on drinking as well as preparing/cooking food and brushing teeth was positively associated with receiving advice from the local radio, while the opposite was true for those receiving advice from the water company/leaflet through the post; we suggest this may largely be due to confusion over needing boiled tap water for brushing teeth. No associations were found for demographic factors. We conclude that information dissemination plans should be tailored to the circumstances under which the advice is issued. Water companies should seek to educate the general public about water notices and which actions are safe and unsafe during which notice, as well as construct and disseminate clearer advice on brushing teeth and preparing/cooking food.

  5. A global conformance quality model. A new strategic tool for minimizing defects caused by variation, error, and complexity

    Energy Technology Data Exchange (ETDEWEB)

    Hinckley, C. Martin [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    1994-01-01

    The performance of Japanese products in the marketplace points to the dominant role of quality in product competition. Our focus is motivated by the tremendous pressure to improve conformance quality by reducing defects to previously unimaginable limits in the range of 1 to 10 parts per million. Toward this end, we have developed a new model of conformance quality that addresses each of the three principle defect sources: (1) Variation, (2) Human Error, and (3) Complexity. Although the role of variation in conformance quality is well documented, errors occur so infrequently that their significance is not well known. We have shown that statistical methods are not useful in characterizing and controlling errors, the most common source of defects. Excessive complexity is also a root source of defects, since it increases errors and variation defects. A missing link in the defining a global model has been the lack of a sound correlation between complexity and defects. We have used Design for Assembly (DFA) methods to quantify assembly complexity and have shown that assembly times can be described in terms of the Pareto distribution in a clear exception to the Central Limit Theorem. Within individual companies we have found defects to be highly correlated with DFA measures of complexity in broad studies covering tens of millions of assembly operations. Applying the global concepts, we predicted that Motorola`s Six Sigma method would only reduce defects by roughly a factor of two rather than orders of magnitude, a prediction confirmed by Motorola`s data. We have also shown that the potential defects rates of product concepts can be compared in the earliest stages of development. The global Conformance Quality Model has demonstrated that the best strategy for improvement depends upon the quality control strengths and weaknesses.

  6. Final technical report for Phenomic Analysis of Natural and Induced Variation in Brachypodium Distachyon DE-SC0001526

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, John P. [USDA ARS Western Regional Research Center, Albany, NY (United States)

    2014-12-17

    The goal of this project was to apply high-throughput, non-destructive phenotyping (phenomics) to collections of natural variants and induced mutants of the model grass Brachypodium distachyon and characterize a small subset of that material in detail. B. distachyon is well suited to this phenomic approach because its small size and rapid generation time allow researchers to grow many plants under carefully controlled conditions. In addition, the simple diploid genetics, high quality genome sequence and existence of numerous experimental tools available for B. distachyon allow us to rapidly identify genes affecting specific phenotypes. Our phenomic analysis revealed great diversity in biofuel-relevant traits like growth rate, biomass and photosynthetic rate. This clearly demonstrated the feasibility of applying a phenomic approach to the model grass B. distachyon. We also demonstrated the utility of B. distachyon for studying mature root system, something that is virtually impossible to do with biomass crops. We showed tremendous natural variation in root architecture that can potentially be used to design crops with superior nutrient and water harvesting capability. Finally, we demonstrated the speed with which we can link specific genes to specific phenotypes by studying two mutants in detail. Importantly, in both cases, the specific biological lessons learned were grass-specific and could not have been learned from a dicot model system. Furthermore, one of the genes affects cell wall integrity and thus may be a useful target in the context of biomass crop improvement. Ultimately, all this information can be used to accelerate the creation of improved biomass crops.

  7. Causes of variation in soil carbon simulations from CMIP5 Earth system models and comparison with observations

    Directory of Open Access Journals (Sweden)

    K. E. O. Todd-Brown

    2013-03-01

    Full Text Available Stocks of soil organic carbon represent a large component of the carbon cycle that may participate in climate change feedbacks, particularly on decadal and centennial timescales. For Earth system models (ESMs, the ability to accurately represent the global distribution of existing soil carbon stocks is a prerequisite for accurately predicting future carbon–climate feedbacks. We compared soil carbon simulations from 11 model centers to empirical data from the Harmonized World Soil Database (HWSD and the Northern Circumpolar Soil Carbon Database (NCSCD. Model estimates of global soil carbon stocks ranged from 510 to 3040 Pg C, compared to an estimate of 1260 Pg C (with a 95% confidence interval of 890–1660 Pg C from the HWSD. Model simulations for the high northern latitudes fell between 60 and 820 Pg C, compared to 500 Pg C (with a 95% confidence interval of 380–620 Pg C for the NCSCD and 290 Pg C for the HWSD. Global soil carbon varied 5.9 fold across models in response to a 2.6-fold variation in global net primary productivity (NPP and a 3.6-fold variation in global soil carbon turnover times. Model–data agreement was moderate at the biome level (R2 values ranged from 0.38 to 0.97 with a mean of 0.75; however, the spatial distribution of soil carbon simulated by the ESMs at the 1° scale was not well correlated with the HWSD (Pearson correlation coefficients less than 0.4 and root mean square errors from 9.4 to 20.8 kg C m−2. In northern latitudes where the two data sets overlapped, agreement between the HWSD and the NCSCD was poor (Pearson correlation coefficient 0.33, indicating uncertainty in empirical estimates of soil carbon. We found that a reduced complexity model dependent on NPP and soil temperature explained much of the 1° spatial variation in soil carbon within most ESMs (R2 values between 0.62 and 0.93 for 9 of 11 model centers. However, the same reduced complexity model only explained 10% of the spatial variation in HWSD

  8. Spatial variations of Pb in the vertical zone of the soil-plant system in the Changbai Mountain National Nature Reserve

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The characteristics of vertical and horizontal variations of lead element(Pb) in soil-plant system of vertical zone in Changbai Mountain National Nature Reserve(CNNR) were studied.The results showed that Pb concentrations in soils of vertical zone are all above 25 mg/kg,and the average Pb concentration of each soil zone negatively correlates its degree of variation,i.e.brown coniferous forest soil zone has the lowest average Pb concentration of four soil zones,and the highest horizontal variation; however,mountain soddy forest soil has the highest average Pb concentration,and the lowest horizontal variation; the average concentration of plant Pb of each plant zone is lower than the worldwide average level of Pb in plant( Clarke),respectively,and plant Pb content order is consistent with soil Pb content order,but their horizontal variations are different from those in soil zones,the variation of mountain tundra forest zone is highest,but Betula ermanii forest zone the lowest.Vertical variation of plant Pb is obviously higher than that in soils with variation coefficient of 89.76%; the enrichment capability of plant for Pb is depended on the plant types and the different organs of plant; parent material and parent rock,pH values,soil organic matter and soil particle fraction etc.are the main factors influencing variations of Pb content in soil-plant system of vertical zone in CNNR.

  9. Linking differential domain functions of the GS3 protein to natural variation of grain size in rice.

    Science.gov (United States)

    Mao, Hailiang; Sun, Shengyuan; Yao, Jialing; Wang, Chongrong; Yu, Sibin; Xu, Caiguo; Li, Xianghua; Zhang, Qifa

    2010-11-09

    Grain yield in many cereal crops is largely determined by grain size. Here we report the genetic and molecular characterization of GS3, a major quantitative trait locus for grain size. It functions as a negative regulator of grain size and organ size. The wild-type isoform is composed of four putative domains: a plant-specific organ size regulation (OSR) domain in the N terminus, a transmembrane domain, a tumor necrosis factor receptor/nerve growth factor receptor (TNFR/NGFR) family cysteine-rich domain, and a von Willebrand factor type C (VWFC) in the C terminus. These domains function differentially in grain size regulation. The OSR domain is both necessary and sufficient for functioning as a negative regulator. The wild-type allele corresponds to medium grain. Loss of function of OSR results in long grain. The C-terminal TNFR/NGFR and VWFC domains show an inhibitory effect on the OSR function; loss-of-function mutations of these domains produced very short grain. This study linked the functional domains of the GS3 protein to natural variation of grain size in rice.

  10. Natural Nuclear Reactor Oklo and Variation of Fundamental Constants Part 1: Computation of Neutronic of Fresh Core

    CERN Document Server

    Petrov, Yu V; Onegin, M S; Petrov, V Yu; Sakhnovskii, E G; Petrov, Yu.V.

    2006-01-01

    Using a modern methods of reactor physics we have performed the full-scale calculations of the natural reactor Oklo. For reliability we have used the recent version of two Monte Carlo codes: the Russian code MCU REA and world wide known code MCNP (USA). Both codes produce close results. We constructed computer model of zone RZ2 of reactor Oklo which takes into account all details of design and composition. The calculations were performed for the three fresh cores with different uranium contents. Multiplication factors, reactivities and neutron fluxes were calculated. We estimated also the temperature and void effects for the fresh core. As would be expected, we have found for the fresh core a great difference between reactor spectra and Maxwell's one, which was used before for averaging cross sections in the Oklo reactor. The averaged cross section of Sm and its dependence on the shift of resonance position (due to variation of fundamental constants) are significantly different from previous results. Contrary...

  11. [Diversity and genetic stability of yeast flocculation caused by variation of tandem repeats in yeast flocculin genes].

    Science.gov (United States)

    Yue, Feng; Guo, Xuena; He, Xiuping; Zhang, Borun

    2013-07-01

    Yeast flocculation is described as a reversible, asexual and calcium dependent process, in which cells adhere to form flocs by interaction of specific cell surface proteins named flocculins on yeast cells with mannose residues present on the cell wall of adjacent yeast cells. Yeast flocculation provides a very economical and convenient pathway for separation of yeast cells from the fermentation broth or removal of heavy metal ions from effluent. A large number of tandem repeats have been found in genes encoding flocculins, which not only have great regulatory effect on the structure and function of flocculins, generating the diversity of flocculation characteristics, but lead to genetic instability in flocculation as well for driving slippage and recombination reactions within and between FLO genes. Here, the research progress in effect of variation of tandem repeats in FLO genes on flocculation characteristics and genetic stability were reviewed to direct and promote the controllable application of flocculation in industrial fermentation process and environmental remediation.

  12. Coupled effects of natural and anthropogenic controls on seasonal and spatial variations of river water quality during baseflow in a coastal watershed of Southeast China.

    Directory of Open Access Journals (Sweden)

    Jinliang Huang

    Full Text Available Surface water samples of baseflow were collected from 20 headwater sub-watersheds which were classified into three types of watersheds (natural, urban and agricultural in the flood, dry and transition seasons during three consecutive years (2010-2012 within a coastal watershed of Southeast China. Integrating spatial statistics with multivariate statistical techniques, river water quality variations and their interactions with natural and anthropogenic controls were examined to identify the causal factors and underlying mechanisms governing spatiotemporal patterns of water quality. Anthropogenic input related to industrial effluents and domestic wastewater, agricultural activities associated with the precipitation-induced surface runoff, and natural weathering process were identified as the potential important factors to drive the seasonal variations in stream water quality for the transition, flood and dry seasons, respectively. All water quality indicators except SRP had the highest mean concentrations in the dry and transition seasons. Anthropogenic activities and watershed characteristics led to the spatial variations in stream water quality in three types of watersheds. Concentrations of NH(4(+-N, SRP, K(+, COD(Mn, and Cl- were generally highest in urban watersheds. NO3(-N Concentration was generally highest in agricultural watersheds. Mg(2+ concentration in natural watersheds was significantly higher than that in agricultural watersheds. Spatial autocorrelations analysis showed similar levels of water pollution between the neighboring sub-watersheds exhibited in the dry and transition seasons while non-point source pollution contributed to the significant variations in water quality between neighboring sub-watersheds. Spatial regression analysis showed anthropogenic controls played critical roles in variations of water quality in the JRW. Management implications were further discussed for water resource management. This research

  13. The Impact of Superoxide Dismutase-1 Genetic Variation on Cardiovascular and All-Cause Mortality in a Prospective Cohort Study: The Yamagata (Takahata) Study

    Science.gov (United States)

    Otaki, Yoichiro; Watanabe, Tetsu; Nishiyama, Satoshi; Takahashi, Hiroki; Arimoto, Takanori; Shishido, Tetsuro; Miyamoto, Takuya; Konta, Tsuneo; Shibata, Yoko; Sato, Hidenori; Kawasaki, Ryo; Daimon, Makoto; Ueno, Yoshiyuki; Kato, Takeo; Kayama, Takamasa; Kubota, Isao

    2016-01-01

    Background Oxidative stress is a major cause of cardiovascular disease. Superoxide dismutase-1 (SOD1) is an antioxidant that protects against oxidative stress. Deoxyribonucleic acid (DNA) variations such as single nucleotide polymorphism (SNP) or haplotypes within the SOD gene are reportedly associated with the development of cardiovascular disease. However, it remains to be determined whether SOD1 variability is associated with cardiovascular or all-cause mortality in the general population. Methods and Results This prospective cohort study included 2799 subjects who participated in a community-based health study with a 10-year follow-up. We genotyped 639 SNPs and found the association of SNP rs1041740 and rs17880487 within a SOD1 gene with cardiovascular mortality. There were 193 deaths during the follow-up period including 57 cardiovascular deaths. Multivariate Cox proportional hazard regression analysis revealed that the homozygous T-allele of rs1041740 was associated with all-cause and cardiovascular deaths after adjusting for confounding factors. The net reclassification index was significantly improved by adding rs1041740 as a cardiovascular risk factor. On the other hand, cardiovascular death was not observed in homozygous T-allele carriers of rs17880487. Haplotype analysis identified the haplotype with T-allele of rs1041740 and that with T-allele of rs17880487 as increasing and decreasing susceptibility for cardiovascular mortality, and it had complementary SNP sequences. Conclusion Variation in the SOD1 gene was associated with cardiovascular deaths in the general population. PMID:27755600

  14. Natural variation in CBF gene sequence, gene expression and freezing tolerance in the Versailles core collection of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Brunel Dominique

    2008-10-01

    Full Text Available Abstract Background Plants from temperate regions are able to withstand freezing temperatures due to a process known as cold acclimation, which is a prior exposure to low, but non-freezing temperatures. During acclimation, a large number of genes are induced, bringing about biochemical changes in the plant, thought to be responsible for the subsequent increase in freezing tolerance. Key regulatory proteins in this process are the CBF1, 2 and 3 transcription factors which control the expression of a set of target genes referred to as the "CBF regulon". Results To assess the role of the CBF genes in cold acclimation and freezing tolerance of Arabidopsis thaliana, the CBF genes and their promoters were sequenced in the Versailles core collection, a set of 48 accessions that maximizes the naturally-occurring genetic diversity, as well as in the commonly used accessions Col-0 and WS. Extensive polymorphism was found in all three genes. Freezing tolerance was measured in all accessions to assess the variability in acclimated freezing tolerance. The effect of sequence polymorphism was investigated by evaluating the kinetics of CBF gene expression, as well as that of a subset of the target COR genes, in a set of eight accessions with contrasting freezing tolerance. Our data indicate that CBF genes as well as the selected COR genes are cold induced in all accessions, irrespective of their freezing tolerance. Although we observed different levels of expression in different accessions, CBF or COR gene expression was not closely correlated with freezing tolerance. Conclusion Our results indicate that the Versailles core collection contains significant natural variation with respect to freezing tolerance, polymorphism in the CBF genes and CBF and COR gene expression. Although there tends to be more CBF and COR gene expression in tolerant accessions, there are exceptions, reinforcing the idea that a complex network of genes is involved in freezing tolerance

  15. [Lipoatrophia semicircularis in the male. Coincidence of arterial variations and micro-traumas as a possible disease cause].

    Science.gov (United States)

    Bloch, P H; Runne, U

    1978-05-01

    Semicircular lipoatrophy is a new entity with horizontal depressions involving half the circumference of thigh, on the antero-lateral aspect. After seven female patients we observed this condition for the first time in the male. Therefore semicircular lipoatrophy is not specific to the female. The cause could not be determined clinically, nor by biochemical, immunological or histological methods. In our opinion semicircular lipoatrophy represents an ischemic atrophy of the fatty tissue, manifested by repeated microtraumata (corners of wash-basins, dressing tables or desks). The perfusion on the antero-lateral aspect of the thighs is tenous, especially when the course of the lateral femoral circumflex artery varies from the normal. In this case semicircular anastomotic areas become ischemic and horizontal bands of lipoatrophy result.

  16. Elucidating Batch-to-Batch Variation Caused by Homocoupled Side Products in Solution-Processable Organic Solar Cells

    DEFF Research Database (Denmark)

    Vangerven, Tim; Verstappen, Pieter; Patil, Nilesh;

    2016-01-01

    -coupling reactions does not always proceed as planned, which can result in the generation of side products containing D-D or A-A homocoupling motifs. Previous studies have reported a reduced performance in polymer and small molecule solar cells when such defect structures are present. A general consensus......Conjugated polymers and small molecules based on alternating electron-donating (D) and electron-accepting (A) building blocks have led to state-of-the-art organic solar cell materials governing efficiencies beyond 10%. Unfortunately, the connection of D and A building blocks via cross...... on the impact of homocouplings on device performance is, however, still lacking as is a profound understanding of the underlying causes of the device deterioration. For differentiating the combined effect of molecular weight and homocouplings in polymer solar cells, a systematic study on a small molecule system...

  17. Structural and morphological modifications of the Co-thin films caused by magnetic field and pH variation

    Energy Technology Data Exchange (ETDEWEB)

    Franczak, Agnieszka [LISM EA 4695, Universite de Reims Champagne-Ardenne, UFR Sciences et Naturelles, Bat. 6, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2 (France); Levesque, Alexandra, E-mail: alexandra.levesque@univ-reims.fr [LISM EA 4695, Universite de Reims Champagne-Ardenne, UFR Sciences et Naturelles, Bat. 6, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2 (France); Bohr, Frederic; Douglade, Jacques; Chopart, Jean-Paul [LISM EA 4695, Universite de Reims Champagne-Ardenne, UFR Sciences et Naturelles, Bat. 6, Moulin de la Housse, BP 1039, 51687 Reims Cedex 2 (France)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer Co electrodeposits were obtained at high electrolyte temperature under applied magnetic field. Black-Right-Pointing-Pointer The temperature is commonly used in the industrial process. Black-Right-Pointing-Pointer The effects of magnetic field up to 1 T and pH on structure and morphology were investigated. Black-Right-Pointing-Pointer The high process temperature enhances HER which is diminishing by the magnetic field application. - Abstract: Cobalt films were deposited by use of the electrochemical process from a cobalt (II) sulfate solution on a titanium electrode and characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The experiments at electrolyte temperature of 50 Degree-Sign C were performed which is commonly used in the industrial process. The effects of pH and low uniform magnetic field up to 1 T on structure and morphology changes were investigated. The detected phase composition indicates the presence of both phases: hexagonal centered packed and face centered cubic independent on the pH value and the applied magnetic field amplitude. Calculation of the orientation index of Co phase shows the preferential orientation in the films obtained at higher pH. SEM micro-imagines have shown the nucleus shape transition from coarse-grained to needle-shaped dependent on the application of B-field as well as on the pH variation in the case of higher pH level. Co-films obtained from the electrolyte of low pH were characterized by the fine-grained morphology which was not modified by the influence of magnetic field. AFM images proved the effect on roughness of the Co-films which is closely related with the obtained morphology.

  18. Diversity, geographic distribution, and habitat-specific variations of microbiota in natural populations of the chicken mite, Dermanyssus gallinae.

    Science.gov (United States)

    Moro, Claire Valiente; Thioulouse, Jean; Chauve, Claude; Zenner, Lionel

    2011-07-01

    Dermanyssus gallinae is considered to be the most economically significant ectoparasite to affect egg-laying poultry in Europe. This mite can also act as a vector for a number of pathogens. The array of bacteria associated with D. gallinae mites could provide insight into the biology and population dynamics of arthropods, but at the present time little information is available. To understand the intra- and interpopulation diversity of its associated microbiota, we analyzed the whole internal bacterial community of natural populations of D. gallinae originating from two types of poultry farm habitats (standard and free-range) in two regions of France (Brittany and the Rhone-Alpes). Total DNA was extracted from individual or pooled mites, and polymerase chain reaction temporal temperature gradient gel electrophoresis of 16S rRNA was then done to separate bacterial DNA fragments associated with the host arthropod. A large diversity of bacteria was detected, but principally firmicutes and gamma-Proteobacteria. Between-group analyses of temporal temperature gradient gel electrophoresis-banding patterns revealed that bacterial populations clustered into categories according to their geographic origin and the habitat specifics of the farms. Some degree of stability of bacterial populations was observed within a specific time scale. These results suggest that environmental factors either recent (e.g., poultry farming practices) or long-standing (e.g., geographic isolation) may affect the bacterial communities present in D. gallinae. Further knowledge of the microbiota associated with D. gallinae and its variation would indeed offer new perspectives for biological control methods to prevent the establishment, proliferation, and transmission of pathogenic bacteria.

  19. Natural nuclear reactor at Oklo and variation of fundamental constants: Computation of neutronics of a fresh core

    Science.gov (United States)

    Petrov, Yu. V.; Nazarov, A. I.; Onegin, M. S.; Petrov, V. Yu.; Sakhnovsky, E. G.

    2006-12-01

    Using modern methods of reactor physics, we performed full-scale calculations of the Oklo natural reactor. For reliability, we used recent versions of two Monte Carlo codes: the Russian code MCU-REA and the well-known international code MCNP. Both codes produced similar results. We constructed a computer model of the Oklo reactor zone RZ2 which takes into account all details of design and composition. The calculations were performed for three fresh cores with different uranium contents. Multiplication factors, reactivities, and neutron fluxes were calculated. We also estimated the temperature and void effects for the fresh core. As would be expected, we found for the fresh core a significant difference between reactor and Maxwell spectra, which had been used before for averaging cross sections in the Oklo reactor. The averaged cross section of 62149Sm and its dependence on the shift of a resonance position Er (due to variation of fundamental constants) are significantly different from previous results. Contrary to the results of previous papers, we found no evidence of a change of the samarium cross section: a possible shift of the resonance energy is given by the limits -73⩽ΔEr⩽62 meV. Following tradition, we have used formulas of Damour and Dyson to estimate the rate of change of the fine structure constant α. We obtain new, more accurate limits of -4×10-17⩽α·/α⩽3×10-17yr-1. Further improvement of the accuracy of the limits can be achieved by taking account of the core burn-up. These calculations are in progress.

  20. Spatiotemporal variation of radon and carbon dioxide concentrations in an underground quarry: coupled processes of natural ventilation, barometric pumping and internal mixing.

    Science.gov (United States)

    Perrier, Frédéric; Richon, Patrick

    2010-04-01

    Radon-222 and carbon dioxide concentrations have been measured during several years at several points in the atmosphere of an underground limestone quarry located at a depth of 18 m in Vincennes, near Paris, France. Both concentrations showed a seasonal cycle. Radon concentration varied from 1200 to 2000 Bq m(-3) in summer to about 800-1400 Bq m(-3) in winter, indicating winter ventilation rates varying from 0.6 to 2.5 x 10(-6) s(-1). Carbon dioxide concentration varied from 0.9 to 1.0% in summer, to about 0.1-0.3% in winter. Radon concentration can be corrected for natural ventilation using temperature measurements. The obtained model also accounts for the measured seasonal variation of carbon dioxide. After correction, radon concentrations still exhibit significant temporal variation, mostly associated with the variation of atmospheric pressure, with coupling coefficients varying from -7 to -26 Bq m(-3) hPa(-1). This variation can be accounted for using a barometric pumping model, coupled with natural ventilation in winter, and including internal mixing as well. After correction, radon concentrations exhibit residual temporal variation, poorly correlated between different points, with standard deviations varying from 3 to 6%. This study shows that temporal variation of radon concentrations in underground cavities can be understood to a satisfactory level of detail using non-linear and time-dependent modelling. It is important to understand the temporal variation of radon concentrations and the limitations in their modelling to monitor the properties of natural or artificial underground settings, and to be able to assess the existence of new processes, for example associated with the preparatory phases of volcanic eruptions or earthquakes.

  1. The ETFDH c.158A>G Variation Disrupts the Balanced Binding of ESE and ESS Proteins Causing Missplicing and Multiple acyl-CoA Dehydrogenation Deficiency

    DEFF Research Database (Denmark)

    Olsen, Rikke K J; Brøner, Sabrina; Sabaratnam, Rugivan

    2013-01-01

    Multiple acyl-CoA dehydrogenation deficiency is a disorder of fatty acid and amino acid oxidation caused by defects of electron transfer flavoprotein (ETF) or its dehydrogenase (ETFDH). A clear relationship between genotype and phenotype makes genotyping of patients important not only diagnostica......Multiple acyl-CoA dehydrogenation deficiency is a disorder of fatty acid and amino acid oxidation caused by defects of electron transfer flavoprotein (ETF) or its dehydrogenase (ETFDH). A clear relationship between genotype and phenotype makes genotyping of patients important not only......-down of nuclear proteins, we show that the c.158A>G variation increases the strength of a preexisting exonic splicing silencer (ESS) motif UAGGGA. This ESS motif binds splice inhibitory hnRNP A1, hnRNP A2/B1, and hnRNP H proteins. Binding of these inhibitory proteins prevents binding of the positive splicing...

  2. Natural selection of human embryos: impaired decidualization of endometrium disables embryo-maternal interactions and causes recurrent pregnancy loss.

    Directory of Open Access Journals (Sweden)

    Madhuri Salker

    Full Text Available BACKGROUND: Recurrent pregnancy loss (RPL, defined as 3 or more consecutive miscarriages, is widely attributed either to repeated chromosomal instability in the conceptus or to uterine factors that are poorly defined. We tested the hypothesis that abnormal cyclic differentiation of endometrial stromal cells (ESCs into specialized decidual cells predisposes to RPL, based on the observation that this process may not only be indispensable for placenta formation in pregnancy but also for embryo recognition and selection at time of implantation. METHODOLOGY/PRINCIPAL FINDINGS: Analysis of mid-secretory endometrial biopsies demonstrated that RPL is associated with decreased expression of the decidual marker prolactin (PRL but increased levels of prokineticin-1 (PROK1, a cytokine that promotes implantation. These in vivo findings were entirely recapitulated when ESCs were purified from patients with and without a history of RPL and decidualized in culture. In addition to attenuated PRL production and prolonged and enhanced PROK1 expression, RPL was further associated with a complete dysregulation of both markers upon treatment of ESC cultures with human chorionic gonadotropin, a glycoprotein hormone abundantly expressed by the implanting embryo. We postulated that impaired embryo recognition and selection would clinically be associated with increased fecundity, defined by short time-to-pregnancy (TTP intervals. Woman-based analysis of the mean and mode TTP in a cohort of 560 RPL patients showed that 40% can be considered "superfertile", defined by a mean TTP of 3 months or less. CONCLUSIONS: Impaired cyclic decidualization of the endometrium facilitates implantation yet predisposes to subsequent pregnancy failure by disabling natural embryo selection and by disrupting the maternal responses to embryonic signals. These findings suggest a novel pathological pathway that unifies maternal and embryonic causes of RPL.

  3. The dappled nature of causes of psychiatric illness: replacing the organic-functional/hardware-software dichotomy with empirically based pluralism.

    Science.gov (United States)

    Kendler, K S

    2012-04-01

    Our tendency to see the world of psychiatric illness in dichotomous and opposing terms has three major sources: the philosophy of Descartes, the state of neuropathology in late nineteenth century Europe (when disorders were divided into those with and without demonstrable pathology and labeled, respectively, organic and functional), and the influential concept of computer functionalism wherein the computer is viewed as a model for the human mind-brain system (brain=hardware, mind=software). These mutually re-enforcing dichotomies, which have had a pernicious influence on our field, make a clear prediction about how 'difference-makers' (aka causal risk factors) for psychiatric disorders should be distributed in nature. In particular, are psychiatric disorders like our laptops, which when they dysfunction, can be cleanly divided into those with software versus hardware problems? I propose 11 categories of difference-makers for psychiatric illness from molecular genetics through culture and review their distribution in schizophrenia, major depression and alcohol dependence. In no case do these distributions resemble that predicted by the organic-functional/hardware-software dichotomy. Instead, the causes of psychiatric illness are dappled, distributed widely across multiple categories. We should abandon Cartesian and computer-functionalism-based dichotomies as scientifically inadequate and an impediment to our ability to integrate the diverse information about psychiatric illness our research has produced. Empirically based pluralism provides a rigorous but dappled view of the etiology of psychiatric illness. Critically, it is based not on how we wish the world to be but how the difference-makers for psychiatric illness are in fact distributed.

  4. A Possible Cause for Different Diurnal Variations of Warm Season Rainfall as Shown in Station Observations and TRMM 3B42 Data over the Southeastern Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    CHEN Haoming; YUAN Weihua; LI Jian; YU Rucong

    2012-01-01

    In this study,records from a 3-yr intensified observational experiment at eight stations along the hillside of Seqilashan over the southeastern Tibetan Plateau were analyzed and combined with records at 28 routine observation stations in the Chinese National Meteorological Station Network to investigate the influences of station location on the different diurnal rainfall variations between station records and Tropical Rainfall Measuring Mission (TRMM) data products.The results indicate that the diurnal variation of warm season rainfall is closely related to location of stations.The prevailing nocturnal rainfall peak in observations at routine stations can be largely attributed to the relatively lower location of the stations,which are mostly situated in valleys.The records at Seqilashan stations on hillsides revealed an evident diurnal afternoon peak of warm season rainfall,similar to that indicated by TRMM data.The different diurnal phases between valley and hillside stations are closely related to the orographically induced regional circulations caused by the complex topography over the Tibetan Plateau.The results of this study indicate that the prevailing nocturnal rainfall associated with the relatively lower location of routine observation stations can partially explain the diurnal rainfall variations between observation station records and TRMM data.

  5. Variation in the Intensity of Selection on Codon Bias over Time Causes Contrasting Patterns of Base Composition Evolution in Drosophila

    Science.gov (United States)

    Jackson, Benjamin C.; Campos, José L.; Haddrill, Penelope R.; Charlesworth, Brian

    2017-01-01

    Four-fold degenerate coding sites form a major component of the genome, and are often used to make inferences about selection and demography, so that understanding their evolution is important. Despite previous efforts, many questions regarding the causes of base composition changes at these sites in Drosophila remain unanswered. To shed further light on this issue, we obtained a new whole-genome polymorphism data set from D. simulans. We analyzed samples from the putatively ancestral range of D. simulans, as well as an existing polymorphism data set from an African population of D. melanogaster. By using D. yakuba as an outgroup, we found clear evidence for selection on 4-fold sites along both lineages over a substantial period, with the intensity of selection increasing with GC content. Based on an explicit model of base composition evolution, we suggest that the observed AT-biased substitution pattern in both lineages is probably due to an ancestral reduction in selection intensity, and is unlikely to be the result of an increase in mutational bias towards AT alone. By using two polymorphism-based methods for estimating selection coefficients over different timescales, we show that the selection intensity on codon usage has been rather stable in D. simulans in the recent past, but the long-term estimates in D. melanogaster are much higher than the short-term ones, indicating a continuing decline in selection intensity, to such an extent that the short-term estimates suggest that selection is only active in the most GC-rich parts of the genome. Finally, we provide evidence for complex evolutionary patterns in the putatively neutral short introns, which cannot be explained by the standard GC-biased gene conversion model. These results reveal a dynamic picture of base composition evolution. PMID:28082609

  6. Temporal Trends in Geographical Variation in Breast Cancer Mortality in China, 1973–2005: An Analysis of Nationwide Surveys on Cause of Death

    Directory of Open Access Journals (Sweden)

    Changfa Xia

    2016-09-01

    Full Text Available To describe geographical variation in breast cancer mortality over time, we analysed breast cancer mortality data from three retrospective national surveys on causes of death in recent decades in China. We first calculated the age-standardized mortality rate (ASMR for each of the 31 provinces in mainland China stratified by survey period (1973–1975, 1990–1992 and 2004–2005. To test whether the geographical variation in breast cancer mortality changed over time, we then estimated the rate ratio (RR for the aggregated data for seven regions and three economic zones using generalized linear models. Finally, we examined the correlation between mortality rate and several macro-economic measures at the provincial level. We found that the overall ASMR increased from 2.98 per 100,000 in 1973–1975 to 3.08 per 100,000 in 1990–1992, and to 3.85 per 100,000 in 2004–2005. Geographical variation in breast cancer mortality also increased significantly over time at the regional level (p = 0.002 but not at the economic zone (p = 0.089 level, with RR being generally lower for Western China (Northwest and Southwest and higher in Northeast China over the three survey periods. These temporal and spatial trends in breast cancer mortality were found to be correlated with per capita gross domestic product, number of hospitals and health centres’ beds per 10,000 population and number of practicing doctors per 10,000 population, and average number of live births for women aged 15–64. It may be necessary to target public health policies in China to address the widening geographic variation in breast cancer mortality, and to take steps to ensure that the ease of access and the quality of cancer care across the country is improved for all residents.

  7. Temporal Trends in Geographical Variation in Breast Cancer Mortality in China, 1973–2005: An Analysis of Nationwide Surveys on Cause of Death

    Science.gov (United States)

    Xia, Changfa; Kahn, Clare; Wang, Jinfeng; Liao, Yilan; Chen, Wanqing; Yu, Xue Qin

    2016-01-01

    To describe geographical variation in breast cancer mortality over time, we analysed breast cancer mortality data from three retrospective national surveys on causes of death in recent decades in China. We first calculated the age-standardized mortality rate (ASMR) for each of the 31 provinces in mainland China stratified by survey period (1973–1975, 1990–1992 and 2004–2005). To test whether the geographical variation in breast cancer mortality changed over time, we then estimated the rate ratio (RR) for the aggregated data for seven regions and three economic zones using generalized linear models. Finally, we examined the correlation between mortality rate and several macro-economic measures at the provincial level. We found that the overall ASMR increased from 2.98 per 100,000 in 1973–1975 to 3.08 per 100,000 in 1990–1992, and to 3.85 per 100,000 in 2004–2005. Geographical variation in breast cancer mortality also increased significantly over time at the regional level (p = 0.002) but not at the economic zone (p = 0.089) level, with RR being generally lower for Western China (Northwest and Southwest) and higher in Northeast China over the three survey periods. These temporal and spatial trends in breast cancer mortality were found to be correlated with per capita gross domestic product, number of hospitals and health centres’ beds per 10,000 population and number of practicing doctors per 10,000 population, and average number of live births for women aged 15–64. It may be necessary to target public health policies in China to address the widening geographic variation in breast cancer mortality, and to take steps to ensure that the ease of access and the quality of cancer care across the country is improved for all residents. PMID:27690073

  8. Accounting for regional variation in both natural environment and human disturbance to improve performance of multimetric indices of lotic benthic diatoms.

    Science.gov (United States)

    Tang, Tao; Stevenson, R Jan; Infante, Dana M

    2016-10-15

    Regional variation in both natural environment and human disturbance can influence performance of ecological assessments. In this study we calculated 5 types of benthic diatom multimetric indices (MMIs) with 3 different approaches to account for variation in ecological assessments. We used: site groups defined by ecoregions or diatom typologies; the same or different sets of metrics among site groups; and unmodeled or modeled MMIs, where models accounted for natural variation in metrics within site groups by calculating an expected reference condition for each metric and each site. We used data from the USEPA's National Rivers and Streams Assessment to calculate the MMIs and evaluate changes in MMI performance. MMI performance was evaluated with indices of precision, bias, responsiveness, sensitivity and relevancy which were respectively measured as MMI variation among reference sites, effects of natural variables on MMIs, difference between MMIs at reference and highly disturbed sites, percent of highly disturbed sites properly classified, and relation of MMIs to human disturbance and stressors. All 5 types of MMIs showed considerable discrimination ability. Using different metrics among ecoregions sometimes reduced precision, but it consistently increased responsiveness, sensitivity, and relevancy. Site specific metric modeling reduced bias and increased responsiveness. Combined use of different metrics among site groups and site specific modeling significantly improved MMI performance irrespective of site grouping approach. Compared to ecoregion site classification, grouping sites based on diatom typologies improved precision, but did not improve overall performance of MMIs if we accounted for natural variation in metrics with site specific models. We conclude that using different metrics among ecoregions and site specific metric modeling improve MMI performance, particularly when used together. Applications of these MMI approaches in ecological assessments

  9. Fine-Scale Microclimatic Variation Can Shape the Responses of Organisms to Global Change in Both Natural and Urban Environments.

    Science.gov (United States)

    Pincebourde, Sylvain; Murdock, Courtney C; Vickers, Mathew; Sears, Michael W

    2016-07-01

    When predicting the response of organisms to global change, models use measures of climate at a coarse resolution from general circulation models or from downscaled regional models. Organisms, however, do not experience climate at such large scales. The climate heterogeneity over a landscape and how much of that landscape an organism can sample will determine ultimately the microclimates experienced by organisms. This past few decades has seen an important increase in the number of studies reporting microclimatic patterns at small scales. This synthesis intends to unify studies reporting microclimatic heterogeneity (mostly temperature) at various spatial scales, to infer any emerging trends, and to discuss the causes and consequences of such heterogeneity for organismal performance and with respect to changing land use patterns and climate. First, we identify the environmental drivers of heterogeneity across the various spatial scales that are pertinent to ectotherms. The thermal heterogeneity at the local and micro-scales is mostly generated by the architecture or the geometrical features of the microhabitat. Then, the thermal heterogeneity experienced by individuals is modulated by behavior. Second, we survey the literature to quantify thermal heterogeneity from the micro-scale up to the scale of a landscape in natural habitats. Despite difficulties in compiling studies that differ much in their design and aims, we found that there is as much thermal heterogeneity across micro-, local and landscape scales, and that the temperature range is large in general (>9 °C on average, and up to 26 °C). Third, we examine the extent to which urban habitats can be used to infer the microclimatic patterns of the future. Urban areas generate globally drier and warmer microclimatic patterns and recent evidence suggest that thermal traits of ectotherms are adapted to them. Fourth, we explore the interplay between microclimate heterogeneity and the behavioral thermoregulatory

  10. Antipsychotic polypharmacy and risk of death from natural causes in patients with schizophrenia: a population-based nested case-control study

    DEFF Research Database (Denmark)

    Baandrup, Lone; Gasse, Christiane; Jensen, Vibeke

    2010-01-01

    , 2005, obtained from central Danish registers. From the study population of 27,633 patients with ICD-8- and ICD-10-diagnosed schizophrenia or other mainly nonaffective psychoses, aged 18-53 years, we identified 193 cases who died of natural causes within a 2-year period and 1,937 age- and sex...

  11. Effects of long-term exposure to air pollution on natural-cause mortality : an analysis of 22 European cohorts within the multicentre ESCAPE project

    NARCIS (Netherlands)

    Beelen, Rob; Raaschou-Nielsen, Ole; Stafoggia, Massimo; Andersen, Zorana Jovanovic; Weinmayr, Gudrun; Hoffmann, Barbara; Wolf, Kathrin; Samoli, Evangelia; Fischer, Paul; Nieuwenhuijsen, Mark; Vineis, Paolo; Xun, Wei W.; Katsouyanni, Klea; Dimakopoulou, Konstantina; Oudin, Anna; Forsberg, Bertil; Modig, Lars; Havulinna, Aki S.; Lanki, Timo; Turunen, Anu; Oftedal, Bente; Nystad, Wenche; Nafstad, Per; De Faire, Ulf; Pedersen, Nancy L.; Ostenson, Claes-Goeran; Fratiglioni, Laura; Penell, Johanna; Korek, Michal; Pershagen, Goeran; Eriksen, Kirsten Thorup; Overvad, Kim; Ellermann, Thomas; Eeftens, Marloes; Peeters, Petra H.; Meliefste, Kees; Wang, Meng; Bueno-de-Mesquita, Bas; Sugiri, Dorothea; Kraemer, Ursula; Heinrich, Joachim; de Hoogh, Kees; Key, Timothy; Peters, Annette; Hampel, Regina; Concin, Hans; Nagel, Gabriele; Ineichen, Alex; Schaffner, Emmanuel; Probst-Hensch, Nicole; Kuenzli, Nino; Schindler, Christian; Schikowski, Tamara; Adam, Martin; Phuleria, Harish; Vilier, Alice; Clavel-Chapelon, Francoise; Declercq, Christophe; Grioni, Sara; Krogh, Vittorio; Tsai, Ming-Yi; Ricceri, Fulvio; Sacerdote, Carlotta; Galassi, Claudia; Migliore, Enrica; Ranzi, Andrea; Cesaroni, Giulia; Badaloni, Chiara; Forastiere, Francesco; Tamayo, Ibon; Amiano, Pilar; Dorronsoro, Miren; Katsoulis, Michail; Trichopoulou, Antonia; Brunekreef, Bert; Hoek, Gerard

    2014-01-01

    Background Few studies on long-term exposure to air pollution and mortality have been reported from Europe. Within the multicentre European Study of Cohorts for Air Pollution Effects (ESCAPE), we aimed to investigate the association between natural-cause mortality and long-term exposure to several a

  12. Estimating gas escape through taliks in relict submarine permafrost and methane hydrate deposits under natural climate variation

    Science.gov (United States)

    Frederick, J. M.; Buffett, B. A.

    2013-12-01

    predictions of gas flux to the water column as a result of relict permafrost-associated gas hydrate dissociation due to natural climate variations. Several hydrate saturation values (20%, 50%, 80% pore volume within hydrate layers) and talik widths (0.5 km, 1.0 km, 1.5 km, 2.0 km) are explored for model parameters representative of the 20 m isobath at the North American Beaufort and East Siberian Arctic Seas (ESAS). Preliminary results estimate the maximum present-day gas flux at the North American Beaufort is 0.229 kg/yr/m2 (average 0.005 kg/yr/m2), which produces a methane concentration of 75 nM in the overlying water column for a representative ocean current of 4 cm/s. For the ESAS, preliminary results estimate the maximum present-day gas flux is 0.277 kg/yr/m2 (average 0.030 kg/yr/m2), which produces a methane concentration of 452 nM in the overlying water column. A desired outcome of this study is to provide a framework for discussion on the potential magnitude of methane release that might be attributed to relict permafrost-associated hydrate deposits in regions where the submarine permafrost has been compromised.

  13. Characterization of natural variation for zinc, iron and manganese accumulation and zinc exposure response in Brassica rapa L.

    NARCIS (Netherlands)

    Wu, J.; Schat, H.; Koornneef, M.; Wang, X.; Aarts, M.G.M.

    2007-01-01

    Brassica rapa L. is an important vegetable crop in eastern Asia. The objective of this study was to investigate the genetic variation in leaf Zn, Fe and Mn accumulation, Zn toxicity tolerance and Zn efficiency in B. rapa. In total 188 accessions were screened for their Zn-related characteristics in

  14. Immunological variation in Taenia solium porcine cysticercosis: measurement on the variation of the antibody immune response of naturally infected pigs against antigens extracted from their own cysticerci and from those of different pigs.

    Science.gov (United States)

    Ostoa-Saloma, Pedro; Esquivel-Velázquez, Marcela; Larralde, Carlos

    2013-10-18

    Although it is widely assumed that both antigen and host immunological variability are involved in the variable intensity of natural porcine infections by Taenia solium (T. solium) cysticercis and success of immunodiagnostic tests vaccines, the magnitude of such combined variability has not been studied or measured at all. In this paper we report statistical data on the variability of the antibody response of naturally infected pigs against the antigens extracted from the vesicular fluids of their own infecting cysts (variance within pigs) and against antigen samples extracted from cysts of other cysticercotic pigs (variance among pigs). The variation between pigs was greater than the inter-pigs variations, which suggests that a concomitant immunity process prevents the establishment of cysts coming from a subsequent challenge. In so doing, we found that there is not a single antigenic band that was recognized by all hosts and that antigens varied among the cysts within the same pigs as well as among pigs. Our results may be valuable for the improvement of immunodiagnostic tests and of effective vaccines against naturally acquired porcine T. solium cysticercosis.

  15. Transportation of natural gas : The impact of price variation on the choice between LNG and pipeline infrastructure

    OpenAIRE

    2011-01-01

    The long-distance transportation of natural gas, either in the form of liquefied natural gas (LNG) or by pipeline, is of great importance for both exporting and importing countries. Exporting countries depend on the revenue from exports. Energy security is a major concern for importing countries, especially for the European Union, which is dependent on imports. Long-distance transportation also requires large-scale capital investment in infrastructure involving both states, state-controlled c...

  16. Cycle-by-cycle Variations in a Direct Injection Hydrogen Enriched Compressed Natural Gas Engine Employing EGR at Relative Air-Fuel Ratios.

    Directory of Open Access Journals (Sweden)

    Olalekan Wasiu Saheed

    2014-07-01

    Full Text Available Since the pressure development in a combustion chamber is uniquely related to the combustion process, substantial variations in the combustion process on a cycle-by-cycle basis are occurring. To this end, an experimental study of cycle-by-cycle variation in a direct injection spark ignition engine fueled with natural gas-hydrogen blends combined with exhaust gas recirculation at relative air-fuel ratios was conducted. The impacts of relative air-fuel ratios (i.e. λ = 1.0, 1.2, 1.3 and 1.4 which represent stoichiometric, moderately lean, lean and very lean mixtures respectively, hydrogen fractions and EGR rates were studied. The results showed that increasing the relative air-fuel ratio increases the COVIMEP. The behavior is more pronounced at the larger relative air-fuel ratios. More so, for a specified EGR rate; increasing the hydrogen fractions decreases the maximum COVIMEP value just as increasing in EGR rates increases the maximum COVIMEP value. (i.e. When percentage EGR rates is increased from 0% to 17% and 20% respectively. The maximum COVIMEP value increases from 6.25% to 6.56% and 8.30% respectively. Since the introduction of hydrogen gas reduces the cycle-by-cycle combustion variation in engine cylinder; thus it can be concluded that addition of hydrogen into direct injection compressed natural gas engine employing EGR at various relative air-fuel ratios is a viable approach to obtain an improved combustion quality which correspond to lower coefficient of variation in imep, (COVIMEP in a direct injection compressed natural gas engine employing EGR at relative air-fuel ratios.

  17. Pregnancy associated plasma protein A2 (PAPP-A2) affects bone size and shape and contributes to natural variation in postnatal growth in mice.

    Science.gov (United States)

    Christians, Julian Kenneth; de Zwaan, Devin Rhys; Fung, Sunny Ho Yeung

    2013-01-01

    Pregnancy associated plasma protein A2 (PAPP-A2) is a protease of insulin-like growth factor binding protein 5 and is receiving increasing attention for its roles in pregnancy and postnatal growth. The goals of the present study were to characterize the effects of PAPP-A2 deletion on bone size and shape in mice at 10 weeks of age, and to determine whether Pappa2 is the gene responsible for a previously-identified quantitative trait locus (QTL) contributing to natural variation in postnatal growth in mice. Mice homozygous for constitutive PAPP-A2 deletion were lighter than wild-type littermates, and had smaller mandible dimensions and shorter skull, humerus, femur, tibia, pelvic girdle, and tail bone. Furthermore, PAPP-A2 deletion reduced mandible dimensions and the lengths of the skull, femur, pelvic girdle, and tail bone more than would be expected due to the effect on body mass. In addition to its effects on bone size, PAPP-A2 deficiency also altered the shape of the mandible and pelvic girdle, as assessed by geometric morphometrics. Mice homozygous for the PAPP-A2 deletion had less deep mandibles, and pelvic girdles with a more feminine shape. Using a quantitative complementation test, we confirmed that Pappa2 is responsible for the effects of the previously-identified QTL, demonstrating that natural variation in the Pappa2 gene contributes to variation in postnatal growth in mice. If similar functional variation in the Pappa2 gene exists in other species, effects of this variation on the shape of the pelvic girdle might explain the previously-reported associations between Pappa2 SNPs and developmental dysplasia of the hip in humans, and birthing in cattle.

  18. An Inquiry into the nature, causes and distribution of wealth in the Cape Colony, 1652-1795

    NARCIS (Netherlands)

    Fourie, J.

    2012-01-01

    Three important questions about the Dutch Cape Colony are investigated in this dissertation: 1) how affluent were Cape settlers, 2) what were the causes of such wealth, and 3) how was the wealth distributed? Using a variety of statistical sources, most notably the detailed probate inventories and au

  19. Tests for the replication of an association between Egfr and natural variation in Drosophila melanogaster wing morphology

    Directory of Open Access Journals (Sweden)

    Dodgson James

    2005-08-01

    Full Text Available Abstract Background Quantitative differences between individuals stem from a combination of genetic and environmental factors, with the heritable variation being shaped by evolutionary forces. Drosophila wing shape has emerged as an attractive system for genetic dissection of multi-dimensional traits. We utilize several experimental genetic methods to validation of the contribution of several polymorphisms in the Epidermal growth factor receptor (Egfr gene to wing shape and size, that were previously mapped in populations of Drosophila melanogaster from North Carolina (NC and California (CA. This re-evaluation utilized different genetic testcrosses to generate heterozygous individuals with a variety of genetic backgrounds as well as sampling of new alleles from Kenyan stocks. Results Only one variant, in the Egfr promoter, had replicable effects in all new experiments. However, expanded genotyping of the initial sample of inbred lines rendered the association non-significant in the CA population, while it persisted in the NC sample, suggesting population specific modification of the quantitative trait nucleotide QTN effect. Conclusion Dissection of quantitative trait variation to the nucleotide level can identify sites with replicable effects as small as one percent of the segregating genetic variation. However, the testcross approach to validate QTNs is both labor intensive and time-consuming, and is probably less useful than resampling of large independent sets of outbred individuals.

  20. Patterns and causes of demographic variation in a harvested moose population: evidence for the effects of climate and density-dependent drivers.

    Science.gov (United States)

    Brown, Glen S

    2011-11-01

    1. Better understanding of the mechanisms affecting demographic variation in ungulate populations is needed to support sustainable management of harvested populations. While studies of moose Alces alces L. populations have previously explored temporal variation in demographic processes, managers responsible for populations that span large heterogeneous landscapes would benefit from an understanding of how demography varies across biogeographical gradients in climate and other population drivers. Evidence of thresholds in population response to manageable and un-manageable drivers could aid resource managers in identifying limits to the magnitude of sustainable change. 2. Generalized additive models (GAMs) were used to evaluate the relative importance of population density, habitat abundance, summer and winter climatic conditions, primary production, and harvest intensity in explaining spatial variation in moose vital rates in Ontario, Canada. Tree regression was used to test for thresholds in the magnitudes of environmental predictor variables that significantly affected population vital rates. 3. Moose population growth rate was negatively related to moose density and positively related to the abundance of mixed deciduous habitat abundant in forage. Calf recruitment was negatively related to a later start of the growing season and calf harvest. The ratio of bulls to cows was related to male harvest and hunter access, and thresholds were evident in predictor variables for all vital rate models. 4. Findings indicate that the contributions of density-dependent and independent factors can vary depending on the scale of population process. The importance of density dependence and habitat supply to low-density ungulate populations was evident, and management strategies for ungulates may be improved by explicitly linking forest management and harvest. Findings emphasize the importance of considering summer climatic influences to ungulate populations, as

  1. Chronic somatic comorbidity and excess mortality due to natural causes in persons with schizophrenia or bipolar affective disorder.

    Directory of Open Access Journals (Sweden)

    Thomas Munk Laursen

    Full Text Available BACKGROUND: Suicide and death by accidents in persons with schizophrenia and bipolar disorder are common, but excess mortality from natural death accounts for even more years of life lost. The impact of somatic comorbidity, however, often is not duly considered in analyses and explanations of excess mortality in patients with psychotic disorders. OBJECTIVE/METHODS: This study investigates and evaluates the impact of 19 severe chronic diseases on excess mortality due to diseases and medical conditions (natural death in individuals with psychotic disorders compared with the general population using a population-based cohort study in Denmark. Incidence/mortality rate ratios of admission/mortality were calculated using survival analysis. RESULTS: Cohort members with psychotic disorders had higher incidence rates of hospital contacts for almost all of the 19 disorders than the general population. The mortality rate ratio (MRR of natural death was 7.10 (95% CI 6.45, 7.81 for schizophrenic men, decreasing to 4.64 (95% CI 4.21, 5.10 after adjustment for the somatic disorders. The same pattern existed in women and in both genders with bipolar disorder. Highest MRRs were observed for psychotic patients without hospital admissions with the investigated somatic disorders. CONCLUSION: Chronic somatic diseases accounted for half of the excess mortality in patients with schizophrenia or bipolar disorder. Chronic disorders investigated in this paper seem to be under-treated or under-detected among such patients.

  2. Natural Variation in "Drosophila" Larval Reward Learning and Memory Due to a cGMP-Dependent Protein Kinase

    Science.gov (United States)

    Kaun, Karla R.; Hendel, Thomas; Gerber, Bertram; Sokolowski, Marla B.

    2007-01-01

    Animals must be able to find and evaluate food to ensure survival. The ability to associate a cue with the presence of food is advantageous because it allows an animal to quickly identify a situation associated with a good, bad, or even harmful food. Identifying genes underlying these natural learned responses is essential to understanding this…

  3. Geographic and phenotypic variation in heartwood and essential-oil characters in natural populations of Santalum austrocaledonicum in Vanuatu.

    Science.gov (United States)

    Page, Tony; Southwell, Ian; Russell, Mike; Tate, Hanington; Tungon, Joseph; Sam, Chanel; Dickinson, Geoff; Robson, Ken; Leakey, Roger R B

    2010-08-01

    Phenotypic variation in heartwood and essential-oil characters of Santalum austrocaledonicum was assessed across eleven populations on seven islands of Vanuatu. Trees differed significantly in their percentage heartwood cross-sectional area and this varied independently of stem diameter. The concentrations of the four major essential-oil constituents (alpha-santalol, beta-santalol, (Z)-beta-curcumen-12-ol, and cis-nuciferol) of alcohol-extracted heartwood exhibited at least tenfold and continuous tree-to-tree variation. Commercially important components alpha- and beta-santalol found in individual trees ranged from 0.8-47% and 0-24.1%, respectively, across all populations, and significant (P<0.05) differences for each were found between individual populations. The Erromango population was unique in that the mean concentrations of its monocyclic ((Z)-beta-curcumen-12-ol and cis-nuciferol) sesquiterpenes exceeded those of its bi- and tricyclic (alpha- and beta-santalol) sesquiterpenes. Heartwood colour varied between trees and spanned 65 colour categories, but no identifiable relationships were found between heartwood colour and alpha- and beta-santalol, although a weak relationship was evident between colour saturation and total oil concentration. These results indicate that the heartwood colour is not a reliable predictive trait for oil quality. The results of this study highlight the knowledge gaps in fundamental understanding of heartwood biology in Santalum genus. The intraspecific variation in heartwood cross-sectional area, oil concentration, and oil quality traits is of considerable importance to the domestication of sandalwood and present opportunities for the development of highly superior S. austrocaledonicum cultivars that conform to the industry's International Standards used for S. album.

  4. Short baseline variations in site response and wave-propagation effects and their structural causes: Four examples in and around the santa clara valley, California

    Science.gov (United States)

    Hartzell, S.; Ramirez-Guzman, L.; Carver, D.; Liu, P.

    2010-01-01

    Ground motion records of local and regional events from a portable array are used to investigate the structural causes of variations in ground motion over distances of a few hundred meters to a few kilometers in the sedimentary basin environment of the Santa Clara Valley, California, and its margins. Arrays of portable seismic stations are used to target four study areas with different ground motion patterns: (1) an edge of the alluvial basin extending up onto a marginal ridge (Blossom Hill), (2) a Cenozoic basin with a nearly flat bottom (Cupertino Basin), (3) a long, narrow Cenozoic basin with a steep V profile (Evergreen Basin), and (4) a line perpendicular to the trace of the Hayward fault. Average peak velocities on Blossom Hill from local earthquakes are a factor of 2.5 times higher than nearby valley sites. Three-dimensional (3D) modeling is used to conclude that the majority of the amplification is due to lower shear-wave velocities along a local fault zone (Shannon–Berrocal). Site amplification over the Cupertino Basin in the frequency band 0.5–4 Hz is generally low (less than 2.0 relative to a Mesozoic rock site) and spatially uniform. This response is attributed to the shallow, flat-bottomed shape of the basin and the uniform, flat-laying sedimentary fill. In contrast, site amplification in the Evergreen Basin generally exceeds 3.0 and is attributed to the deep, V-shaped geometry of the basin and younger sedimentary fill. 3D waveform modeling shows the elongated shape of the Evergreen Basin causes more efficient trapping of long-period waves for sources along the long axis of the basin. A low-velocity zone is postulated along the Hayward fault with a width between 100 and 200 m, based on elevated site response along the fault trace and 4.5-Hz fault zone guided waves on the horizontal components of stations near the fault.

  5. 瓦块固有频率对可倾瓦轴承频变刚度的影响%Effect of Pad Natural Frequency on Frequency-variation Stiffness of Tilting Pad Bearings

    Institute of Scientific and Technical Information of China (English)

    洪红伦; 许吉敏; 陈润霖; 张帆; 吴立明; 袁小阳

    2016-01-01

    uation that vibration frequency is close to its natural frequency is easily appeared for the pad of light load ( unloaded pad for an example),which will cause resonance phenomenon.In order to ensure vibration frequency is greater than natural frequency of pad to produce high stiffness,it is necessary to take natural frequency and frequency⁃variation stiffness into consideration to design pivot coefficient and inertia of unloaded pads in design of the tilting pad bearings.

  6. Genome-wide association implicates numerous genes underlying ecological trait variation in natural populations of Populus trichocarpa.

    Science.gov (United States)

    McKown, Athena D; Klápště, Jaroslav; Guy, Robert D; Geraldes, Armando; Porth, Ilga; Hannemann, Jan; Friedmann, Michael; Muchero, Wellington; Tuskan, Gerald A; Ehlting, Jürgen; Cronk, Quentin C B; El-Kassaby, Yousry A; Mansfield, Shawn D; Douglas, Carl J

    2014-07-01

    In order to uncover the genetic basis of phenotypic trait variation, we used 448 unrelated wild accessions of black cottonwood (Populus trichocarpa) from much of its range in western North America. Extensive data from large-scale trait phenotyping (with spatial and temporal replications within a common garden) and genotyping (with a 34 K Populus single nucleotide polymorphism (SNP) array) of all accessions were used for gene discovery in a genome-wide association study (GWAS). We performed GWAS with 40 biomass, ecophysiology and phenology traits and 29,355 filtered SNPs representing 3518 genes. The association analyses were carried out using a Unified Mixed Model accounting for population structure effects among accessions. We uncovered 410 significant SNPs using a Bonferroni-corrected threshold (P<1.7×10(-6)). Markers were found across 19 chromosomes, explained 1-13% of trait variation, and implicated 275 unique genes in trait associations. Phenology had the largest number of associated genes (240 genes), followed by biomass (53 genes) and ecophysiology traits (25 genes). The GWAS results propose numerous loci for further investigation. Many traits had significant associations with multiple genes, underscoring their genetic complexity. Genes were also identified with multiple trait associations within and/or across trait categories. In some cases, traits were genetically correlated while in others they were not.

  7. Transformation of Collagen into Gelatine in Historical Leather and Parchment Caused by Natural Deterioration and Moist Treatment

    DEFF Research Database (Denmark)

    Larsen, René

    2013-01-01

    -like substance that may dissolve on contact with water or even at room temperature at relative humidity levels normal used for storage in archives, libraries and museums. Morphological transformation of fibres upon wetting at room temperature can be observed partly by the naked eye, and characterized more fully...... conservation and restoration water-based treatments have been co-related with the frequent presence of some level of gelatinisation damage, especially in the case of degraded parchment, a finding which is consistent with the fact that direct exposure to water can cause gelatinisation of such degraded fibres...

  8. Agro-ecological variations of sheath rot disease of rice caused by Sarocladium oryzae and DNA fingerprinting of the pathogen's population structure.

    Science.gov (United States)

    Tajul Islam Chowdhury, M; Salim Mian, M; Taher Mia, M A; Rafii, M Y; Latif, M A

    2015-12-28

    To examine the impact of regional and seasonal variations on the incidence and severity of sheath rot, a major seed-borne disease of rice caused by Sarocladium oryzae, data on incidence and severity were collected from 27 selected fields in the Gazipur, Rangpur, Bogra, Chittagong, Comilla, Gopalgonj, Jessore, Manikgonj, and Bhola districts of Bangladesh in rain-fed and irrigated conditions. Cultural variability of 29 pathogen isolates obtained from 8 different locations was studied on potato dextrose agar (PDA) and genetic variability was determined by DNA fingerprinting using variable number tandem repeat-polymerase chain reaction markers. Overall, disease incidence and severity were higher in irrigated rice. Disease incidence and severity were highest in the Bhola district in rain-fed rice and lowest in irrigated rice. Mycelial growth of 29 representative isolates was found to vary on PDA and the isolates were divided into 6 groups. The range of the overall size of conidia of the selected isolates was 2.40-7.20 x 1.20-2.40 μm. Analysis of the DNA fingerprint types of the 29 isolates of S. oryzae, obtained from the amplification reactions, revealed 10 fingerprinting types (FPTs) that were 80% similar. FPT-1 was the largest group and included 13 isolates (44.8%), while FPT-2 was the third largest group and included 3 isolates. Each of FPT-3, 4, 5, and 6 included only 1 isolate. We observed no relationship between cultural and genetic groupings.

  9. Air temperature and CO{sub 2} variations in a naturally ventilated classroom under a Nordic climate

    Energy Technology Data Exchange (ETDEWEB)

    Celis Mercier, S.; Potvin, A. [Laval Univ., Quebec City, PQ (Canada). School of Architecture; Tardif, M. [Sustainable Buildings and Communities, Ottawa, ON (Canada)

    2009-07-01

    This paper presented preliminary results of the first stage of an ongoing passive cooling pre-design evaluation for the refurbishment of a primary school in Ste-Marie-de-Beauce, Quebec. The 1950's building did not have any mechanical systems apart from the central hot-water heating system. The viability of passive cooling and natural ventilation was evaluated by considering whether the surrounding outside conditions were favourable to passive cooling and natural ventilation and whether the the building envelope was optimized to minimize solar gain into the space. The study also evaluated the effectiveness of window operation in controlling a classroom thermal environment and indoor air quality. Field measurements and questionnaires were collected in the fall of 2008. A systemic approach integrating acoustic, thermal, visual and olfactory ambiences was proposed. 17 refs., 13 figs.

  10. Variation in the response of the invasive species Potamopyrgus antipodarum (Smith) to natural (cyanobacterial toxin) and anthropogenic (herbicide atrazine) stressors

    Energy Technology Data Exchange (ETDEWEB)

    Gerard, Claudia [UMR CNRS Ecobio 6553, Equipe Physiologie et Ecophysiologie, Universite de Rennes 1, Avenue du General Leclerc, 35042 Rennes cedex (France)]. E-mail: claudia.gerard@univ-rennes1.fr; Poullain, Virginie [UMR CNRS Ecobio 6553, Equipe Physiologie et Ecophysiologie, Universite de Rennes 1, Avenue du General Leclerc, 35042 Rennes cedex (France)

    2005-11-15

    In the context of increasing freshwater pollution, the impact on life-traits (survival, growth and fecundity) and locomotion of Potamopyrgus antipodarum of a 5-week field-concentration exposure to the cyanobacterial toxin microcystin-LR and the triazine herbicide, atrazine was studied. Whatever the age of exposed snails (juveniles, subadults, adults), microcystin-LR induced a decrease in survival, growth and fecundity but had no effect on locomotion. Atrazine induced a decrease in locomotory activity but had no significant effect on the life-traits. These results are discussed in terms of consequences to field populations. - At concentrations relevant to the field, cyanobacterial toxins (natural) and atrazine (anthropogenic) are detrimental to the gastropod Potamopyrgus antipodarum, with a greater toxicity for the natural (vs anthropogenic) stressor.

  11. Insect responses to host plant provision beyond natural boundaries: latitudinal and altitudinal variation in a Chinese fig wasp community.

    Science.gov (United States)

    Wang, Rong; Compton, Stephen G; Quinnell, Rupert J; Peng, Yan-Qiong; Barwell, Louise; Chen, Yan

    2015-09-01

    Many plants are grown outside their natural ranges. Plantings adjacent to native ranges provide an opportunity to monitor community assembly among associated insects and their parasitoids in novel environments, to determine whether gradients in species richness emerge and to examine their consequences for host plant reproductive success. We recorded the fig wasps (Chalcidoidea) associated with a single plant resource (ovules of Ficus microcarpa) along a 1200 km transect in southwest China that extended for 1000 km beyond the tree's natural northern range margin. The fig wasps included the tree's agaonid pollinator and other species that feed on the ovules or are their parasitoids. Phytophagous fig wasps (12 species) were more numerous than parasitoids (nine species). The proportion of figs occupied by fig wasps declined with increasing latitude, as did the proportion of utilized ovules in occupied figs. Species richness, diversity, and abundance of fig wasps also significantly changed along both latitudinal and altitudinal gradients. Parasitoids declined more steeply with latitude than phytophages. Seed production declined beyond the natural northern range margin, and at high elevation, because pollinator fig wasps became rare or absent. This suggests that pollinator climatic tolerances helped limit the tree's natural distribution, although competition with another species may have excluded pollinators at the highest altitude site. Isolation by distance may prevent colonization of northern sites by some fig wasps and act in combination with direct and host-mediated climatic effects to generate gradients in community composition, with parasitoids inherently more sensitive because of declines in the abundance of potential hosts.

  12. [Nature and sensitivity of bacteria superinfecting plantar ulcers caused by leprosy at the Marchoux Institute, Bamako, Mali].

    Science.gov (United States)

    Tiendrebeogo, A; Coulibaly, I; Sarr, A M; Sow, S O

    1999-01-01

    To determine potential usefulness of antimicrobial agents and to guide their prescription in the treatment of leprosy plantar ulcers, we conducted an in vitro study about germs' nature and sensitivity to antibiotics. We took samples of plantar ulcers secretion from 107 patients at Marchoux Institute. 92.5% of those ulcers were infected. These samples revealed 145 strains of micro-organisms among those, Staphylococcus aureus (70 strains) and genus Pseudomonas (41 strains) were the most frequent. These bacteria were resistant to several antibiotics currently used at Marchoux Institute (tetracycline, penicillin, cotrimoxazol and erythromicin). Antibiotics, efficient at 80% on tested strains, were expensive for patients. They cannot be recommended for the treatment of local infections. These results outline that the main treatment in plantar ulcers is based upon antiseptic solutions and keeping feet at rest. Antibiotherapy in case of extension of local infection would be based on the results of a previous study of sensitivity.

  13. Long-term temperature variations in the stratosphere and troposphere caused by changes in gas and aerosol composition of the atmosphere

    Science.gov (United States)

    Dyominov, I.; Zadorozhny, A.

    A numerical 2-D zonally averaged interactive dynamical radiative-photochemical model of the troposphere and stratosphere including aerosol physics is used for investigation of long-term temperature changes caused by anthropogenic pollution of the atmosphere by CO2 , CH4, N2O, CFCs, HCFCs, HFCs, CH 3CCl 3 and CCl4 as well as by discharges to the atmosphere of sulphate species during the Pinatubo eruption. The model allows calculating self-consistently diabatic circulation, temperature, gaseous composition of the troposphere and stratosphere at latitudes from the South to North Poles, as well as distribution of sulphate aerosol particles and polar stratospheric clouds (PSCs) of types I and II. The scenarios of expected changes of the anthropogenic pollutants for the period from 1990 through 2050 are taken from Climate Change 1995. The calculations of the long-term temperature variations due to anthropogenic emission s show that the greatest temperature changes are observed in the Southern Hemisphere in winter/spring periods. For example, the temperature changes at a height of 40 km at 45°S in December 2050 are about -4.85 K, 0.89 K, -2.21 K, and -4.32 K respectively for anthropogenic discharges of CO2, CH4, N2O, and chlorine species. The changes in the Northern Hemisphere are smaller. They are equal to about -4.5 K, 0.68 K, -1.46 K, and -3.17 K at 45°N. The temperature changes in the stratosphere are caused by the corresponding ozone variations and temperature feedbacks. In the troposphere, the temperature changes are determined by the greenhouse effect caused by optically active pollutants. For example, temperature increases near the Earth's surface at 45 °N in December of 2050 due to anthropogenic discharges of CO2, CH4, N2O, and chlorine species are about 0.87 K, 0.19 K, 0.14 K, and 0.32 K, respectively. The calculations show that short -term megaton discharges of sulphate species to the atmosphere during the Pinatubo eruption led to significant long

  14. Determination of natural frequencies by coupled method of homotopy perturbation and variational method for strongly nonlinear oscillators

    Science.gov (United States)

    Akbarzade, M.; Langari, J.

    2011-02-01

    In this paper a new approach combining the features of the homotopy concept with variational approach is proposed to find accurate analytical solutions for nonlinear oscillators with and without a fractional power restoring force. Since the first-order approximation leads to very accurate results, comparisons with other results are presented to show the effectiveness of this method. The validity of the method is independent of whether or not there exist small or large parameters in the considered nonlinear equations; the obtained results prove the validity and efficiency of the method, which can be easily extended to other strongly nonlinear problems. At the end we compare our procedure with the optimal homotopy perturbation method.

  15. On the Nature of Extraversion: Variation in Conditioned Contextual Activation of Dopamine-Facilitated Affective, Cognitive, and Motor Processes

    Directory of Open Access Journals (Sweden)

    Richard allen Depue

    2013-06-01

    Full Text Available Research supports an association between extraversion and dopamine (DA functioning. DA facilitates incentive motivation and the conditioning and incentive encoding of contexts that predict reward. Therefore, we assessed whether extraversion is related to the efficacy of acquiring conditioned contextual facilitation of three processes that are dependent on DA: motor velocity, positive affect, and visuospatial working memory. We exposed high and low extraverts to three days of association of drug reward (methylphenidate, MP with a particular laboratory context (Paired group, a test day of conditioning, and three days of extinction in the same laboratory. A Placebo group and an Unpaired group (that had MP in a different laboratory context served as controls. Conditioned contextual facilitation was assessed by (i presenting video clips that varied in their pairing with drug and laboratory context and in inherent incentive value, and (ii measuring increases from day 1 to Test day on the three processes above. Results showed acquisition of conditioned contextual facilitation across all measures to video clips that had been paired with drug and laboratory context in the Paired high extraverts, but no conditioning in the Paired low extraverts (nor in either of the control groups. Increases in the Paired high extraverts were correlated across the three measures. Also, conditioned facilitation was evident on the first day of extinction in Paired high extraverts, despite the absence of the unconditioned effects of MP. By the last day of extinction, responding returned to day 1 levels. The findings suggest that extraversion is associated with variation in the acquisition of contexts that predict reward. Over time, this variation may lead to differences in the breadth of networks of conditioned contexts. Thus, individual differences in extraversion may be maintained by activation of differentially encoded central representations of incentive contexts that

  16. On the nature of extraversion: variation in conditioned contextual activation of dopamine-facilitated affective, cognitive, and motor processes.

    Science.gov (United States)

    Depue, Richard A; Fu, Yu

    2013-01-01

    Research supports an association between extraversion and dopamine (DA) functioning. DA facilitates incentive motivation and the conditioning and incentive encoding of contexts that predict reward. Therefore, we assessed whether extraversion is related to the efficacy of acquiring conditioned contextual facilitation of three processes that are dependent on DA: motor velocity, positive affect, and visuospatial working memory. We exposed high and low extraverts to three days of association of drug reward (methylphenidate, MP) with a particular laboratory context (Paired group), a test day of conditioning, and three days of extinction in the same laboratory. A Placebo group and an Unpaired group (that had MP in a different laboratory context) served as controls. Conditioned contextual facilitation was assessed by (i) presenting video clips that varied in their pairing with drug and laboratory context and in inherent incentive value, and (ii) measuring increases from day 1 to Test day on the three processes above. Results showed acquisition of conditioned contextual facilitation across all measures to video clips that had been paired with drug and laboratory context in the Paired high extraverts, but no conditioning in the Paired low extraverts (nor in either of the control groups). Increases in the Paired high extraverts were correlated across the three measures. Also, conditioned facilitation was evident on the first day of extinction in Paired high extraverts, despite the absence of the unconditioned effects of MP. By the last day of extinction, responding returned to day 1 levels. The findings suggest that extraversion is associated with variation in the acquisition of contexts that predict reward. Over time, this variation may lead to differences in the breadth of networks of conditioned contexts. Thus, individual differences in extraversion may be maintained by activation of differentially encoded central representations of incentive contexts that predict reward.

  17. Transformation of collagen into gelatine in historical leather and parchment caused by natural deterioration and moist treatment

    DEFF Research Database (Denmark)

    Larsen, René

    2012-01-01

    The main constituent in leather and parchment is the fibrous protein collagen type I. Experiments and studies have shown that the chemical mechanisms causing deterioration of the collagen structure in these materials are acid hydrolysis and oxidation and that these can be correlated...... to the hydrothermal stability of the material. For parchment and leather tanned with condensed types of vegetable tannins stored under acid conditions, the chemical deterioration may lead to a transformation of the collagen into a gelatine-like substance that may dissolve in water even at ambient temperature....... This process follows certain typical denaturising patterns that can be observed as characteristic morphological transformations of the collagen fibre structure at the microscopic level. Moreover, this transformation process has shown to be the same as that taking place during measurement of the hydrothermal...

  18. Short-term natural δ13C variations in pools and fluxes in a beech forest: the transfer of isotopic signal from recent photosynthates to soil respired CO2

    Science.gov (United States)

    Gavrichkova, O.; Proietti, S.; Moscatello, S.; Portarena, S.; Battistelli, A.; Matteucci, G.; Brugnoli, E.

    2011-03-01

    The fate of photosynthetic products within the plant-soil continuum determines how long the reduced carbon resides within the ecosystem and when it returns back to the atmosphere in the form of respiratory CO2. We have tested the possibility of measuring natural variation in δ13C to disentangle potential times needed to transfer carbohydrates produced by photosynthesis down to roots and, in general, to belowground up to its further release in the form of soil respiration into the atmosphere in a beech (Fagus sylvatica) forest. For these purposes we have measured the variation in stable carbon and oxygen isotope compositions in plant material and in soil respired CO2 every three hours for three consequent days. Possible steps and different signs of post-photosynthetic fractionation during carbon translocation were also identified. A 12 h-periodicity was observed for variation in δ13C in soluble sugars in the top crown leaves and it can be explained by starch day/night dynamics in synthesis and breakdown and by stomatal limitations under elevated vapour pressure deficits. Photosynthetic products were transported down the trunk and mixed with older carbon pools, therefore causing the dampening of the δ13C signal variation. The strongest periodicity of 24 h was found in δ13C in soil respiration indicating changes in root contribution to the total CO2 efflux. Nevertheless, it was possible to identify the speed of carbon translocation through the plant-soil continuum. A period of 24 h was needed to transfer the C assimilated by photosynthesis from the top crown leaves to the tree trunk at breast height and additional 3 h for further respiration of that C by roots and soil microorganisms and its to subsequent diffusion back to the atmosphere.

  19. Short-term natural δ13C variations in pools and fluxes in a beech forest: the transfer of isotopic signal from recent photosynthates to soil respired CO2

    Directory of Open Access Journals (Sweden)

    G. Matteucci

    2011-03-01

    Full Text Available The fate of photosynthetic products within the plant-soil continuum determines how long the reduced carbon resides within the ecosystem and when it returns back to the atmosphere in the form of respiratory CO2. We have tested the possibility of measuring natural variation in δ13C to disentangle potential times needed to transfer carbohydrates produced by photosynthesis down to roots and, in general, to belowground up to its further release in the form of soil respiration into the atmosphere in a beech (Fagus sylvatica forest. For these purposes we have measured the variation in stable carbon and oxygen isotope compositions in plant material and in soil respired CO2 every three hours for three consequent days. Possible steps and different signs of post-photosynthetic fractionation during carbon translocation were also identified. A 12 h-periodicity was observed for variation in δ13C in soluble sugars in the top crown leaves and it can be explained by starch day/night dynamics in synthesis and breakdown and by stomatal limitations under elevated vapour pressure deficits. Photosynthetic products were transported down the trunk and mixed with older carbon pools, therefore causing the dampening of the δ13C signal variation. The strongest periodicity of 24 h was found in δ13C in soil respiration indicating changes in root contribution to the total CO2 efflux. Nevertheless, it was possible to identify the speed of carbon translocation through the plant-soil continuum. A period of 24 h was needed to transfer the C assimilated by photosynthesis from the top crown leaves to the tree trunk at breast height and additional 3 h for further respiration of that C by roots and soil microorganisms and its to subsequent diffusion back to the atmosphere.

  20. Effect of Diesel Engine Converted to Sequential Port Injection Compressed Natural Gas Engine on the Cylinder Pressure vs Crank Angle in Variation Engine Speeds

    OpenAIRE

    Semin; Abdul R. Ismail; Rosli A. Bakar

    2009-01-01

    The diesel engine converted to compressed natural gas (CNG) engine effect is lower in performance. Problem statement: The hypothesis is that the lower performance of CNG engine is caused by the effect of lower in engine cylinder pressure. Are the CNG engine is lower cylinder pressure than diesel engine? This research is conducted to investigate the cylinder pressure of CNG engine as a new engine compared to diesel engine as a baseline engine. Approach: The research approach in this study is b...

  1. Estimating selection through male fitness: three complementary methods illuminate the nature and causes of selection on flowering time.

    Science.gov (United States)

    Austen, Emily J; Weis, Arthur E

    2016-02-24

    Our understanding of selection through male fitness is limited by the resource demands and indirect nature of the best available genetic techniques. Applying complementary, independent approaches to this problem can help clarify evolution through male function. We applied three methods to estimate selection on flowering time through male fitness in experimental populations of the annual plant Brassica rapa: (i) an analysis of mating opportunity based on flower production schedules, (ii) genetic paternity analysis, and (iii) a novel approach based on principles of experimental evolution. Selection differentials estimated by the first method disagreed with those estimated by the other two, indicating that mating opportunity was not the principal driver of selection on flowering time. The genetic and experimental evolution methods exhibited striking agreement overall, but a slight discrepancy between the two suggested that negative environmental covariance between age at flowering and male fitness may have contributed to phenotypic selection. Together, the three methods enriched our understanding of selection on flowering time, from mating opportunity to phenotypic selection to evolutionary response. The novel experimental evolution method may provide a means of examining selection through male fitness when genetic paternity analysis is not possible.

  2. Posttranslational modification and sequence variation of redox-active proteins correlate with biofilm life cycle in natural microbial communities

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Steven [Lawrence Livermore National Laboratory (LLNL); Erickson, Brian K [ORNL; Verberkmoes, Nathan C [ORNL; Hwang, Mona [Lawrence Livermore National Laboratory (LLNL); Shah, Manesh B [ORNL; Hettich, Robert {Bob} L [ORNL; Banfield, Jillian F. [University of California, Berkeley; Thelen, Michael P. [University of California, Berkeley

    2010-01-01

    Characterizing proteins recovered from natural microbial communities affords the opportunity to correlate protein expression and modification with environmental factors, including species composition and successional stage. Proteogenomic and biochemical studies of pellicle biofilms from subsurface acid mine drainage streams have shown abundant cytochromes from the dominant organism, Leptospirillum Group II. These cytochromes are proposed to be key proteins in aerobic Fe(II) oxidation, the dominant mode of cellular energy generation by the biofilms. In this study, we determined that posttranslational modification and expression of amino-acid sequence variants change as a function of biofilm maturation. For Cytochrome579 (Cyt579), the most abundant cytochrome in the biofilms, late developmental-stage biofilms differed from early-stage biofilms in N-terminal truncations and decreased redox potentials. Expression of sequence variants of two monoheme c-type cytochromes also depended on biofilm development. For Cyt572, an abundant membrane-bound cytochrome, the expression of multiple sequence variants was observed in both early and late developmental-stage biofilms; however, redox potentials of Cyt572 from these different sources did not vary significantly. These cytochrome analyses show a complex response of the Leptospirillum Group II electron transport chain to growth within a microbial community and illustrate the power of multiple proteomics techniques to define biochemistry in natural systems.

  3. Seasonal variation and natural infection of Lutzomyia antunesi (Diptera: Psychodidae: Phlebotominae, an endemic species in the Orinoquia region of Colombia

    Directory of Open Access Journals (Sweden)

    Adolfo Vasquez Trujillo

    2013-06-01

    Full Text Available Lutzomyia antunesi has been commonly reported in outbreaks of cutaneous leishmaniasis (CL in the Orinoquia region of Colombia. The bionomics of this species were studied in the municipality of Villavicencio (Meta, Colombia. Sandflies were captured over the course of one week per month for one year in intradomiciliary, peridomiciliary and extradomiciliary housing areas. The captures were performed from 06:00 pm-06:00 am using CDC light traps and the females were processed for polymerase chain reaction (PCR to detect Leishmania spp. A total of 22,097 specimens and 19 species were captured of which Lu. antunesi (89% and Lutzomyia walkeri (5% were the most abundant. Other species recognised as anthropophilic (Lutzomyia panamensis, Lutzomyia gomezi, Lutzomyia flaviscutellata and Lutzomyia fairtigi were present in very low abundance (< 2%. Natural infection with Leishmania spp was detected using PCR in Lu. antunesi, Lu. panamensis and Lu. flavicutellata, showing infection rates of 1%, 4.8% and 7.5%, respectively. The present paper provides information on various ecological aspects of Lu. antunesi. An analysis of seasonality shows that this species increases in abundance in the hottest months (December, January and February, directly correlating with the maximum temperature and inversely correlating with precipitation. The natural infection rate is associated with the peaks of highest abundance.

  4. Seasonal variation and natural infection of Lutzomyia antunesi (Diptera: Psychodidae: Phlebotominae), an endemic species in the Orinoquia region of Colombia

    Science.gov (United States)

    Trujillo, Adolfo Vásquez; Reina, Angélica E González; Orjuela, Agustín Góngora; Suárez, Edgar Prieto; Palomares, Jairo Enrique; Alvarez, Luz Stella Buitrago

    2013-01-01

    Lutzomyia antunesi has been commonly reported in outbreaks of cutaneous leishmaniasis (CL) in the Orinoquia region of Colombia. The bionomics of this species were studied in the municipality of Villavicencio (Meta, Colombia). Sandflies were captured over the course of one week per month for one year in intradomiciliary, peridomiciliary and extradomiciliary housing areas. The captures were performed from 06:00 pm-06:00 am using CDC light traps and the females were processed for polymerase chain reaction (PCR) to detect Leishmania spp. A total of 22,097 specimens and 19 species were captured of which Lu. antunesi (89%) and Lutzomyia walkeri (5%) were the most abundant. Other species recognised as anthropophilic (Lutzomyia panamensis, Lutzomyia gomezi, Lutzomyia flaviscutellata and Lutzomyia fairtigi) were present in very low abundance (< 2%). Natural infection with Leishmania spp was detected using PCR in Lu. antunesi, Lu. panamensis and Lu. flavicutellata, showing infection rates of 1%, 4.8% and 7.5%, respectively. The present paper provides information on various ecological aspects of Lu. antunesi. An analysis of seasonality shows that this species increases in abundance in the hottest months (December, January and February), directly correlating with the maximum temperature and inversely correlating with precipitation. The natural infection rate is associated with the peaks of highest abundance. PMID:23828011

  5. Patterns of nucleotide sequence variation in ICAM1 and TNF genes in twelve ethnic groups of India: roles of demographic history and natural selection

    Indian Academy of Sciences (India)

    Sanghamitra Sengupta; Shabana Farheen; Neelanjana Mukherjee; Partha P. Majumder

    2007-12-01

    We have studied DNA sequence variation in and around the genes ICAM1 and TNF, which play functional and correlated roles in inflammatory processes and immune cell responses, in 12 diverse ethnic groups of India, with a view to investigating the relative roles of demographic history and natural selection in shaping the observed patterns of variation. The total numbers of single nucleotide polymorphisms (SNPs) detected at the ICAM1 and TNF loci were 29 and 12, respectively. Haplotype and allele frequencies differed significantly across populations. The site frequency spectra at these loci were significantly different from those expected under neutrality, and showed an excess of intermediate-frequency variants consistent with balancing selection. However, as expected under balancing selection, there was no significant reduction of $F_{ST}$ values compared to neutral autosomal loci. Mismatch distributions were consistent with population expansion for both loci. On the other hand, the phylogenetic network among haplotypes for the TNF locus was similar to expectations under population expansion, while that for the ICAM1 was as expected under balancing selection. Nucleotide diversity at the ICAM1 locus was an order of magnitude lower in the promoter region, compared to the introns or exons, but no such difference was noted for the TNF gene. Thus, we conclude that the pattern of nucleotide variation in these genes has been modulated by both demographic history and selection. This is not surprising in view of the known allelic associations of several polymorphisms in these genes with various diseases, both infectious and noninfectious.

  6. Variation in Heat-shock Proteins and Photosynthetic Thermotolerance among Natural Populations of Chenopodium album L. from Contrasting Thermal Environments: Implications for Plant Responses to Global Warming

    Institute of Scientific and Technical Information of China (English)

    Deepak Barua; Scott A. Heckathorn; James S. Coleman

    2008-01-01

    Production of heat-shock proteins (Hsps) is a key adaptation to acute heat stress and will be Important in determining plant responses to climate change. Further, intraspecifc variation in Hsps, which will influence species-level response to global warming, has rarely been examined in naturally occurring plants. To understand intraspeciflc variation in plant Hsps and its relevance to global warming, we examined Hsp content and thermotolerance in five naturally occurring populations of Chenopodium album L. from contrasting thermal environments grown at low and high temperatures. As expected,Hsp accumulation varied between populations, but this was related more to habitat variability than to mean temperature.Unexpectedly, Hsp accumulation decreased with increasing variability of habitat temperatures. Hsp accumulation also decreased with increased experimental growth temperatures. Physiological thermotolerance was partitioned into basal and induced components. As with Hsps, induced thermotolerance decreased with increasing temperature variability. Thus,populations native to the more stressful habitats, or grown at higher temperatures, had lower Hsp levels and induced thermotolerance, suggesting a greater reliance on basal mechanisms for thermotolerance. These results suggest that future global climate change will differentially impact ecotypes within species, possibly by selecting for increased basal versus inducible thermotolerance.

  7. Exposure to Low Dose of Cinnabar (a Naturally Occurring Mercuric Sulfide (HgS Caused Neurotoxicological Effects in Offspring Mice

    Directory of Open Access Journals (Sweden)

    Chun-Fa Huang

    2012-01-01

    Full Text Available Cinnabar, a naturally occurring mercuric sulfide (HgS, has long been used in Chinese mineral medicine for more than 2000 years. Although mercury is well-known for its toxicity, whether cinnabar induces neurotoxicity, especially in infants and children, is unknown. The purpose of this study was to explore the neurotoxic effects of low-dose of cinnabar (10 mg/kg/day on developing mice. The results revealed neurobehavioral defects in F1-C-Cin group, which were associated with Hg accumulation, increased NOx levels in whole blood, and Na+/K+-ATPase activities in brain tissues. F1- and F2-Cin-V groups were found to increase brain Hg contents and prominent neurobehavioral defects compared with F1-C-V group, suggesting that the fetal brain was more susceptible to irreversible effects for cinnabar-induced damage. Moreover, F1- and F2-Cin-Cin groups had severely neurobehavioral dysfunctions, closely correlated with the further alteration of NOx levels and Na+/K+-ATPase activities than F1- and F2-C-Cin groups. Effects in F2-Cin-Cin group were more significant than those in F1-Cin-Cin group. In conclusion, this study demonstrates that exposure to low-dose of cinnabar during the perinatal and developmental stages results in irreversible and severe injuries of the neurotoxicity in offspring, and NOx and Na+/K+-ATPase activities may exist potential and useful biomarkers for neurotoxicity-induced by low-doses of mercuric compounds.

  8. Intra-cycle variation of the uterine cavity indentation assessed with three-dimensional ultrasound in natural and stimulated cycles.

    Science.gov (United States)

    Saravelos, Sotirios H; Li, Tin-Chiu

    2016-05-01

    The recent ESHRE-ESGE classification for female genital anomalies attempts to promote objectivity in diagnosis of normal and septate uteri. The aim of this study was to ascertain whether the uterine cavity indentation - the characteristic feature of septate uteri - varies significantly throughout the cycle. Seventy consecutive women underwent three-dimensional ultrasound twice: 35 during the proliferative and luteal phase of a natural cycle, and 35 during the first and final day of a stimulated cycle. Endometrial thickness, interostial distance, cavity indentation and percentage of cavity indentation were all assessed in accordance with the ESHRE-ESGE consensus on diagnosis of female genital anomalies. Overall, throughout both cycles, there was a significant increase in endometrial thickness (from 4.6 mm to 10.2 mm; P cavity indentation (from 30.3% to 15.0%; P uterine cavity indentation has important implications for both clinical practice and research.

  9. A natural neighbour method based on Fraeijs de Veubeke variational principle for materially non-linear problems

    Institute of Scientific and Technical Information of China (English)

    Xiang Li; Serge Cescotto; Barbara Rossi

    2009-01-01

    The natural neighbour method can be considered as one of many variants of the meshless methods. In the present paper, a new approach based on the Fraeijs de Veubeke (FdV) functional, which is initially developed for linear elasticity, is extended to the case of geometrically linear but materially non-linear solids. The new approach provides an original treatment to two classical problems: the numerical evaluation of the integrals over the domain A and the enforcement of boundary conditions of the type ui = uion Su. In the absence of body forces (Fi = 0), it will be shown that the calculation of integrals of the type fA .dA can be avoided and that boundary conditions of the type ui = ui on Su can be imposed in the average sense in general and exactly if ui is linear between two contour nodes, which is obviously the case for ui = 0.

  10. Natural variation in the glucose content of dilute sulfuric acid-pretreated rice straw liquid hydrolysates: implications for bioethanol production.

    Science.gov (United States)

    Goda, Takashi; Teramura, Hiroshi; Suehiro, Miki; Kanamaru, Kengo; Kawaguchi, Hideo; Ogino, Chiaki; Kondo, Akihiko; Yamasaki, Masanori

    2016-05-01

    Rice straw is a promising resource for bioethanol production. Because the glucose content of pretreatment liquid hydrolysates is highly correlated with ethanol yield, the selection of appropriate rice cultivars is essential. The glucose content in liquid hydrolysates of pretreated rice straws of 208 diverse cultivars was evaluated in natural field in 2013 and 2014 using a novel high-throughput system. The glucose content of the rice straw samples varied across cultivars and was affected by environmental factors such as temperature and solar radiation. Several high-quality cultivars exhibiting high glucose content in both years were identified. The results of this study can aid in development of novel rice cultivars suitable as both feedstocks for bioethanol production and cooking.

  11. Seasonal variation and natural infection of Lutzomyia antunesi (Diptera: Psychodidae: Phlebotominae), an endemic species in the Orinoquia region of Colombia.

    Science.gov (United States)

    Vásquez Trujillo, Adolfo; González Reina, Angélica E; Góngora Orjuela, Agustín; Prieto Suárez, Edgar; Palomares, Jairo Enrique; Buitrago Alvarez, Luz Stella

    2013-06-01

    Lutzomyia antunesi has been commonly reported in outbreaks of cutaneous leishmaniasis (CL) in the Orinoquia region of Colombia. The bionomics of this species were studied in the municipality of Villavicencio (Meta, Colombia). Sandflies were captured over the course of one week per month for one year in intradomiciliary, peridomiciliary and extradomiciliary housing areas. The captures were performed from 06:00 pm-06:00 am using CDC light traps and the females were processed for polymerase chain reaction (PCR) to detect Leishmania spp. A total of 22,097 specimens and 19 species were captured of which Lu. antunesi (89%) and Lutzomyia walkeri (5%) were the most abundant. Other species recognised as anthropophilic (Lutzomyia panamensis, Lutzomyia gomezi, Lutzomyia flaviscutellata and Lutzomyia fairtigi) were present in very low abundance (temperature and inversely correlating with precipitation. The natural infection rate is associated with the peaks of highest abundance.

  12. The halt of deep convection in the Greenland Sea: A natural experiment for the study of their causes and effects.

    Science.gov (United States)

    Somavilla Cabrillo, Raquel; Schauer, Ursula; Budeus, Gedeon; Latarius, Katrin

    2015-04-01

    There are only a few sites where the deep ocean is ventilated from the surface. The responsible process known as deep convection is recognized to be a key process on the Earth's climate system, but still it is scarcely observed, and its good representation by global oceanographic and climate models remains unclear. In the Arctic Ocean, the halt of deep convection in the Greenland Sea during the last three decades serves as a natural experiment to study: (1) the conditions that drive the occurrence or not of deep convection and (2) the effects of the halt of deep convection on the thermohaline properties of the deep water masses and circulation both locally and in adjacent ocean basins. Combining oceanic and atmospheric in-situ data together with reanalysis data, we observe that not only on average the winter net heat losses from the ocean to the atmosphere (Qo) have decreased during the last three decades in the Greenland Sea (ΔQo (before the 1980s- after the 1980s) = 25 Wm-2) but the intensity and number of strong cooling events (Qo ≥ 800Wm-2). This last value for convection reaching 2000 m in the Greenland Sea seems critical to make the mixed layer deepening from being a non-penetrative process to one arrested by baroclinic instabilities. Besides, changes in the wind stress curl and preconditioning for deep convection have occurred, hindering also the occurrence of deep convection. Concerning the effects of the halt of deep convection, hydrographic data reveal that the temperature between 2000 meters depth and the sea floor has risen by 0.3 °C in the last 30 years, which is ten times higher than the temperature increase in the global ocean on average, and salinity rose by 0.02 because import of relatively warm and salty Arctic Ocean deep waters continued. The necessary transports to explain the observed changes suggest an increase of Arctic Ocean deep water transport that would have compensated the decrease in deep water formation rate after the 1980s. The

  13. Natural variation at sympathy for the ligule controls penetrance of the semidominant Liguleless narrow-R mutation in Zea mays.

    Science.gov (United States)

    Buescher, Elizabeth M; Moon, Jihyun; Runkel, Anne; Hake, Sarah; Dilkes, Brian P

    2014-10-24

    Leaf architecture determines plant structural integrity, light harvesting, and economic considerations such as plant density. Ligules, junctions at the leaf sheath and blade in grasses, protect stalks from environmental stresses and, in conjunction with auricles, controls leaf angle. Previous studies in mutants have recessive liguleless mutants (lg1 and lg2) and dominant mutations in knotted1-like homeobox genes (Lg3-O, Lg4, and Kn1) involved in ligule development. Recently, a new semidominant liguleless mutant, Liguleless narrow (Lgn-R), has been characterized in maize that affects ligule and auricle development and results in a narrow leaf phenotype. We show that quantitative genetic variation affects penetrance of Lgn-R. To examine the genetic architecture underlying Lgn-R expressivity, crosses between Lgn-R/+ mutants in a B73 background and intermated B73 x Mo17 recombinant inbred lines were evaluated in multiple years and locations. A single main-effect quantitative trait locus (QTL) on chromosome 1 (sympathy for the ligule; sol) was discovered with a Mo17-contributed allele that suppressed Lgn-R mutant phenotypes. This QTL has a genetic-interaction with a locus on chromosome 7 (lucifer; lcf) for which the B73-contributed allele increases the ability of the sol(Mo17) allele to suppress Lgn-R. Neither of the genetic intervals likely to contain sol or lcf overlap with any current liguleless genes nor with previously identified genome-wide association QTL connected to leaf architecture. Analysis of phenotypes across environments further identified a genotype by enviroment interaction determining the strength of the sol x lcf interaction.

  14. Spatio-temporal variation in territory quality and oxidative status: a natural experiment in the Seychelles warbler (Acrocephalus sechellensis).

    Science.gov (United States)

    van de Crommenacker, Janske; Komdeur, Jan; Burke, Terry; Richardson, David S

    2011-05-01

    1. Fluctuations in the quality of the habitat in which an animal lives can have major consequences for its behaviour and physiological state. In poor-quality habitat with low food availability, metabolically intensive foraging activity is likely to result in increased generation of reactive oxygen species, while scarcity of food can lead to a weakening of exogenously derived antioxidant defences. The consequent oxidant/antioxidant imbalance may lead to elevated oxidative stress. 2. Although the link between food availability and oxidative stress has been studied in the laboratory, very little is known about this relationship in the wild. Here, we investigate the association between territory quality (measured through food availability) and oxidative stress in the Seychelles warbler (Acrocephalus sechellensis). 3. Seychelles warblers are insectivorous birds that inhabit a fixed feeding territory year round. Individuals experience profound and rapid local fluctuations in territory quality within these territories, owing to changing patterns of vegetation defoliation resulting from seasonal changes in prevailing wind direction and wind-borne salt spray. 4. As expected, oxidant generation (measured as reactive oxygen metabolites; ROMs) was higher when territory quality was low, but there was no correlation between territory quality and antioxidant capacity (OXY). The negative correlation between territory quality and ROMs was significant between individuals and approached significance within individuals, indicating that the pattern resulted from individual responses to environmental variation. 5. ROMs and OXY levels within individuals were positively correlated, but the relationship between territory quality and ROMs persisted after including OXY as a covariate, implying that oxidative stress occurs in low territory quality conditions. 6. Our results indicate that the oxidative stress balance of an individual is sensitive to relatively short-term changes in territory

  15. Observed changes of temperature extremes during 1960-2005 in China: natural or human-induced variations?

    Science.gov (United States)

    Zhang, Qiang; Li, Jianfeng; David Chen, Yongqin; Chen, Xiaohong

    2011-12-01

    The purpose of this study was to statistically examine changes of surface air temperature in time and space and to analyze two factors potentially influencing air temperature changes in China, i.e., urbanization and net solar radiation. Trends within the temperature series were detected by using Mann-Kendall trend test technique. The scientific problem this study expected to address was that what could be the role of human activities in the changes of temperature extremes. Other influencing factors such as net solar radiation were also discussed. The results of this study indicated that: (1) increasing temperature was observed mainly in the northeast and northwest China; (2) different behaviors were identified in the changes of maximum and minimum temperature respectively. Maximum temperature seemed to be more influenced by urbanization, which could be due to increasing urban albedo, aerosol, and air pollutions in the urbanized areas. Minimum temperature was subject to influences of variations of net solar radiation; (3) not significant increasing and even decreasing temperature extremes in the Yangtze River basin and the regions south to the Yangtze River basin could be the consequences of higher relative humidity as a result of increasing precipitation; (4) the entire China was dominated by increasing minimum temperature. Thus, we can say that the warming process of China was reflected mainly by increasing minimum temperature. In addition, consistently increasing temperature was found in the upper reaches of the Yellow River basin, the Yangtze River basin, which have the potential to enhance the melting of permafrost in these areas. This may trigger new ecological problems and raise new challenges for the river basin scale water resource management.

  16. What a difference a bay makes: natural variation in dietary resources mediates growth in a recently settled herbivorous fish

    Science.gov (United States)

    Priest, Mark A.; Halford, Andrew R.; Clements, Kendall D.; Douglas, Emily; Abellana, Sheena L.; McIlwain, Jennifer L.

    2016-12-01

    Processes acting during the early stages of coral reef fish life cycles have a disproportionate influence on their adult abundance and community structure. Higher growth rates, for example, confer a major fitness advantage in larval and juvenile fishes, with larger fish undergoing significantly less mortality. The role of dietary resources in the size-structuring process has not been well validated, especially at the early post-settlement phase, where competition and predation are seen as preeminent drivers of juvenile fish assemblage structure. Here, we report on a size differential of 10-20% between recently settled Siganus spinus rabbitfish recruits from different bays around the Pacific island of Guam. This difference was maintained across multiple recruitment events within and between years. After confirming the validity of our observations through otolith increment analysis, subsequent investigation into the drivers of this variation revealed significant differences in the structure of algal assemblages between bays, congruent with the observed differences in size of the recently settled fish. Gut analyses showed a greater presence of algal types with higher levels of nitrogen and phosphorus in the stomachs of fish from Tanguisson, the bay with the largest observed recruits. To ensure this mechanism was one of causation and not correlation, we conducted a fully factorial experiment in which S. spinus recruits sampled from different bays were reared on all combinations of algal diets representative of the different bays. Recruits on the `Tanguisson' diet grew faster than recruits on other diets, regardless of their origin. We propose that the greater availability of high-quality dietary resources at this location is likely conferring benefits that impact on the population-level dynamics of this species. The spatial and temporal extent of this process clearly implicates food as a limiting resource, capable of mediating fish population dynamics at multiple

  17. LMWOA (low molecular weight organic acid) exudation by salt marsh plants: Natural variation and response to Cu contamination

    Science.gov (United States)

    Mucha, Ana P.; Almeida, C. Marisa R.; Bordalo, Adriano A.; Vasconcelos, M. Teresa S. D.

    2010-06-01

    This work aimed to evaluate, in vitro, the capability of roots of two salt marsh plants to release low molecular weight organic acids (LMWOAs) and to ascertain whether Cu contamination would stimulate or not organic acids exudation. The sea rush Juncus maritimus and the sea-club rush Scirpus maritimus, both from the lower Douro river estuary (NW Portugal), were used. Plants were collected seasonally, four times a year in 2004, during low tide. After sampling, plant roots were washed for removal of adherent particles and immersed for 2 h in a solution that matched salinity (3) and pH (7.5) of the pore water from the same location to obtain plant exudates. In one of the seasons, similar experiments were carried out but spiking the solution with different amounts of Cu in order to embrace the range between 0 and 1600 nM. In the final solutions as well as in sediment pore water LMWOAs were determined by high performance liquid chromatography. Plants were able to release, in a short period of time, relatively high amounts of LMWOAs (oxalate, citrate, malate, malonate, and succinate). In the sediment pore water oxalate, succinate and acetate were also detected. Therefore, plant roots probably contributed to the presence of some of these organic compounds in pore water. Exudation differed between the plant species and also showed some seasonally variation, particularly for S. maritimus. The release of oxalate by J. maritimus increased with Cu increase in the media. However, exudation of the other LMWOAs did not seem to be stimulated by Cu contamination in the media. This fact is compatible with the existence of alternative internal mechanisms for Cu detoxification, as denoted by the fact that in media contaminated with Cu both plant species accumulated relatively high amounts (29-83%) of the initially dissolved Cu. This study expands our knowledge on the contribution of globally dominant salt marsh plants to the release of LMWOAs into the environment.

  18. Comparative study of the variation of the hydric properties and aspect of natural stone and brick after the application of 4 types of anti-graffiti

    Directory of Open Access Journals (Sweden)

    García, O.

    2010-02-01

    Full Text Available In this article a comparative study of the behaviour of different commercial anti-graffiti on natural stone and brick is presented. 8 different European substrates were selected and 4 commercial anti-graffiti of different chemical nature were applied on these substrates. The variations of their hydric properties and aspect (colour and gloss with regard to the untreated substrates were later studied in the laboratory. The results obtained permitted to assess the suitability of 4 of the main types of chemical formulations employed to be used as anti-graffiti. This study concludes that the sacrificial anti-graffiti with polymeric paraffins in its composition presents the lowest reductions of the hydric properties of the studied substrates, being also the variations in colour the least perceptible.

    En este artículo se presenta un estudio comparativo del comportamiento de diferentes tipos de anti-graffiti comerciales sobre piedra natural y ladrillo. Para ello se seleccionaron 8 tipos de sustratos porosos de diferentes países europeos, sobre los que se aplicaron 4 anti-graffiti de distinta naturaleza química. Posteriormente se estudiaron las variaciones en sus propiedades hídricas y de aspecto (color y brillo con respecto a los sustratos no tratados, en el laboratorio. Los resultados obtenidos han permitido evaluar la idoneidad de 4 de los principales tipos de formulaciones químicas más frecuentemente utilizadas como anti-graffiti sobre sustratos porosos. El estudio concluye que el antigraffiti de sacrificio de composición parafínica es el producto que reduce en menor medida las propiedades hídricas de los sustratos porosos estudiados, y que menores cambios de color produce en los mismos.

  19. INTRASPECIFIC VARIATION OF THE GREEN TURTLE, Chelonia mydas (CHELONIIDAE, IN THE FORAGING AREA OF GORGONA NATURAL NATIONAL PARK (COLOMBIAN PACIFIC

    Directory of Open Access Journals (Sweden)

    Laura Sampson

    2014-06-01

    Full Text Available The size distribution and body condition of the two morphotypes of green turtle (Chelonia mydas foraging in Gorgona Natural National Park (GNNP in the Colombian Pacific was assessed from 2003 to 2012. Measurements of straight carapace length (SCL, curved carapace length (CCL, weight, and body condition of 1,023 turtles captured on the GNNP reefs were recorded. More black turtles (n = 747 than yellow turtles (n = 276 were captured, all of them juveniles. Black turtles were significantly larger and heavier than yellow turtles. The size of recruitment to the neritic zone was 40.0-49.9 cm SCL for both morphotypes, but there were more yellow than black turtles in this size class, indicating a difference in the recruitment pattern. The body condition index of yellow turtles was significantly higher than that of black turtles, which could indicate differences in resource use. Based on our results, we suggest that GNNP might function as a recruitment area for yellow turtles, which arrive at smaller sizes and as part of a coastal migratory route for black turtles, which arrive at larger sizes and maintain residence at this location for an unknown period of time.Variación intraespecífica de la tortuga verde Chelonia mydas (Cheloniidae en el área de forrajeo del Parque Nacional Natural Gorgona (Pacífico colombianoSe comparó la distribución de tallas y condición corporal de los dos morfotipos conocidos de tortuga verde (Chelonia mydas en el área de forrajeo del Parque Nacional Natural Gorgona (PNNG en el Pacífico colombiano entre 2003 y 2012. Se tomaron medidas de largo recto de caparazón (LRC, largo curvo de caparazón (LCC, peso y condición corporal de 1.023 tortugas capturadas en los arrecifes del PNG. Se capturaron más tortugas negras (n = 747 que amarillas (n = 276, todas juveniles. Las tortugas negras fueron significativamente más grandes y pesadas que las amarillas. El tamaño de reclutamiento a la zona nerítica fue de 40,0–49,9 cm

  20. Natural Genetic Variation of Seed Micronutrients of Arabidopsis thaliana Grown in Zinc-Deficient and Zinc-Amended Soil

    Science.gov (United States)

    Chen, Xiaochao; Yuan, Lixing; Ludewig, Uwe

    2016-01-01

    The quality of edible seeds for human and animal nutrition is crucially dependent on high zinc (Zn) and iron (Fe) seed concentrations. The micronutrient bioavailability is strongly reduced by seed phytate that forms complexes with seed cations. Superior genotypes with increased seed Zn concentrations had been identified, but low micronutrient seed levels often prevail when the plants are grown in Zn-deficient soils, which are globally widespread and correlate with human Zn-deficiency. Here, seed Zn concentrations of Arabidopsis accessions grown in Zn-deficient and Zn-amended conditions were measured together with seed Fe and manganese (Mn), in a panel of 108 accessions. By applying genome-wide association, de novo candidate genes potentially involved in the seed micronutrient accumulation were identified. However, a candidate inositol 1,3,4-trisphosphate 5/6-kinase 3 gene (ITPK3), located close to a significant nucleotide polymorphism associated with relative Zn seed concentrations, was dispensable for seed micronutrients accumulation in Col-0. Loss of this gene in itpk3-1 did neither affect phytate seed levels, nor seed Zn, Fe, and Mn. It is concluded that large natural variance of micronutrient seed levels is identified in the population and several accessions maintain high seed Zn despite growth in Zn-deficient conditions. PMID:27507976

  1. Population dynamics of a natural red deer population over 200 years detected via substantial changes of genetic variation.

    Science.gov (United States)

    Hoffmann, Gunther Sebastian; Johannesen, Jes; Griebeler, Eva Maria

    2016-05-01

    Most large mammals have constantly been exposed to anthropogenic influence over decades or even centuries. Because of their long generation times and lack of sampling material, inferences of past population genetic dynamics, including anthropogenic impacts, have only relied on the analysis of the structure of extant populations. Here, we investigate for the first time the change in the genetic constitution of a natural red deer population over two centuries, using up to 200-year-old antlers (30 generations) stored in trophy collections. To the best of our knowledge, this is the oldest DNA source ever used for microsatellite population genetic analyses. We demonstrate that government policy and hunting laws may have strong impacts on populations that can lead to unexpectedly rapid changes in the genetic constitution of a large mammal population. A high ancestral individual polymorphism seen in an outbreeding population (1813-1861) was strongly reduced in descendants (1923-1940) during the mid-19th and early 20th century by genetic bottlenecks. Today (2011), individual polymorphism and variance among individuals is increasing in a constant-sized (managed) population. Differentiation was high among periods (F ST > ***); consequently, assignment tests assigned individuals to their own period with >85% probability. In contrast to the high variance observed at nuclear microsatellite loci, mtDNA (D-loop) was monomorphic through time, suggesting that male immigration dominates the genetic evolution in this population.

  2. Natural genetic variation of seed micronutrients of Arabidopsis thaliana grown in zinc-deficient and zinc-amended soil

    Directory of Open Access Journals (Sweden)

    Xiaochao Chen

    2016-07-01

    Full Text Available The quality of edible seeds for human and animal nutrition is crucially dependent on high zinc (Zn and iron (Fe seed concentrations. The micronutrient bioavailability is strongly reduced by seed phytate that forms complexes with seed cations. Superior genotypes with increased seed Zn concentrations had been identified, but low micronutrient seed levels often prevail when the plants are grown in Zn-deficient soils, which are globally widespread and correlate with human Zn-deficiency. Here, seed Zn concentrations of Arabidopsis accessions grown in Zn-deficient and Zn-amended conditions were measured together with seed Fe and manganese (Mn, in a panel of 108 accessions. By applying genome-wide association, de novo candidate genes potentially involved in the seed micronutrient accumulation were identified. However, a candidate inositol 1,3,4-trisphosphate 5/6-kinase 3 gene (ITPK3, located close to a significant nucleotide polymorphism associated with relative Zn seed concentrations, was dispensable for seed micronutrients accumulation in Col-0. Loss of this gene in itpk3-1 did neither affect phytate seed levels, nor seed Zn, Fe and Mn. It is concluded that large natural variance of micronutrient seed levels is identified in the population and several accessions maintain high seed Zn despite growth in Zn-deficient conditions.

  3. Leaf Morphology Variation of Populus nigra L. in Natural Populations along the Rivers in Croatia and Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Davorin Kajba

    2015-06-01

    Full Text Available Background and Purpose: The aim was to determine the morphological differences between the hairy type of European black poplar (Populus nigra subsp. caudina and the typical type from the riparian forests populations as well as between the river systems. Hairy black poplar spreads in a mosaic pattern across the Submediterranean climatic type along the River Neretva and the typical European black poplar is growing on alluvial soils along large rivers in the territory of Croatia and Bosnia and Herzegovina. Material and Methods: Samples for leaf morphometric analysis were collected in 17 natural populations of European black poplar along six rivers in Croatia and Bosnia and Herzegovina. Results: Discriminant analyses have determined that in the differentiation of population groups largely contribute some characters such as the distance between the leaf widest part and the leaf base (DBW and the petiole length (PL. The differences between populations and analysed groups, as well as the differences between populations belonging to a particular river system, were confirmed for all studied characteristics. Conclusions: Significant differences have been determined between the typical and the hairy type of European black poplar in the studied morphological traits and these dissimilarities are in accordance with the climatic differences in respective habitats of continental riparian forests and the Submediterranean type of climate. Populations sampled in the lower course of the River Neretva, which correspond to the hairy type of the European black poplar, have smaller leaves and a greater angle between the first lower lateral vein and the midrib.

  4. Seasonal and ontogenetic variation of skin microbial communities and relationships to natural disease dynamics in declining amphibians

    Science.gov (United States)

    Longo, Ana V.; Savage, Anna E.; Hewson, Ian; Zamudio, Kelly R.

    2015-01-01

    Recently, microbiologists have focused on characterizing the probiotic role of skin bacteria for amphibians threatened by the fungal disease chytridiomycosis. However, the specific characteristics of microbial diversity required to maintain health or trigger disease are still not well understood in natural populations. We hypothesized that seasonal and developmental transitions affecting susceptibility to chytridiomycosis could also alter the stability of microbial assemblages. To test our hypothesis, we examined patterns of skin bacterial diversity in two species of declining amphibians (Lithobates yavapaiensis and Eleutherodactylus coqui) affected by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). We focused on two important transitions that affect Bd susceptibility: ontogenetic (from juvenile to adult) shifts in E. coqui and seasonal (from summer to winter) shifts in L. yavapaiensis. We used a combination of community-fingerprinting analyses and 16S rRNA amplicon sequencing to quantify changes in bacterial diversity and assemblage composition between seasons and developmental stages, and to investigate the relationship between bacterial diversity and pathogen load. We found that winter-sampled frogs and juveniles, two states associated with increased Bd susceptibility, exhibited higher diversity compared with summer-sampled frogs and adult individuals. Our findings also revealed that hosts harbouring higher bacterial diversity carried lower Bd infections, providing support for the protective role of bacterial communities. Ongoing work to understand skin microbiome resilience after pathogen disturbance has the potential to identify key taxa involved in disease resistance. PMID:26587253

  5. Genetic and morphological variation in natural teak (Tectona grandis) populations of the Western Ghats in Southern India

    Institute of Scientific and Technical Information of China (English)

    P.M. Sreekanth; M. Balasundaran; P.A. Nazeem

    2014-01-01

    Teak (Tectona grandis L.f.) is a popular hardwood species native to South and South-East Asia. The possible association of ampli-fied fragment length polymorphism (AFLP) marker with morphological variables of eleven important characters viz. girth at breast height (GBH), height of tree, bole height, branch knots, presence of fluting, spiral stem, leaf hair, leaf length/breadth ratio, branching pattern, bark colour and petiole shape for nine natural populations comprising 180 genotypes of teak (9 populations × 20 trees). The phenogram constructed using Euclidean distances for the eleven morphological characters showed that the populations were not grouped according to their geographical origin. The Mantel’s test for pairwise correlation between Euclidean distances of different morphological variables and genetic distances from AFLP data revealed that only petiole character (r =0.269; p =0.046) and height of tree (r=0.200;p=0.001) were significantly correlated with that of AFLP data matrix. The nine populations in this study covered a geographic area of about 1000 km stretch along the Western Ghat of South India. A test of correlation between genetic and geographic distance matrices revealed a significant positive correlation (r=0.475;p=0.009). The lack of perfect congruence between morphological and molecular data except for geo-graphic distance, tree height and petiole character suggested that the morphological system might be useful for the morphotypes management but not appropriate to study the genetic structure of the teak populations.

  6. Reproduction-related variation in carbon allocation to woody tissues in Fagus crenata using a natural 13C approach.

    Science.gov (United States)

    Han, Qingmin; Kagawa, Akira; Kabeya, Daisuke; Inagaki, Yoshiyuki

    2016-11-01

    The contribution of new photo-assimilates and stored carbon (C) to plant growth remains poorly understood, especially during reproduction. In order to elucidate how mast seeding affects C allocation to both reproductive and vegetative tissues, we measured biomass increase in each tissue, branch starch concentration and stable C isotope composition (δ(13)C) in bulk leaves, current-year shoots, 3-year branches and tree rings in fruiting and non-fruiting trees for 2 years, as well as in fruits. We isolated the effect of reproduction on C allocation to vegetative growth by comparing (13)C enrichment in woody tissues in fruiting and non-fruiting specimens. Compared with 2‰ (13)C enrichment in shoots relative to leaves from non-fruiting trees, fruiting reduced the enrichment to 1‰ and this reduction disappeared in the following year with no fruiting, indicating that new photo-assimilates are preferentially used for woody tissues even with fruiting burden. In contrast, fruits had up to 2.5‰ (13)C enrichment at mid-summer, which dropped thereafter, indicating that fruit production relies on C storage early in the growing season then shifts to current photo-assimilates. At this tipping point, growth of shoots and cupules had almost finished and nuts had a second rapid growth period thereafter. Together with shorter shoots but higher biomass increment per length in fruiting trees than non-fruiting trees, these results indicate that the C limitation due to fruit burden is minimized by fine-tuning of allocation of old C stores and new photo-assimilates, along with the growth pattern in various tissues. Furthermore, fruiting had no significant effect on starch concentration in 3-year-old branches, which became fully depleted during leaf and flower flushing but were quickly replenished. These results indicate that reproduction affects C allocation to branches but not its source or storage. These reproduction-related variations in the fate of C have implications for

  7. AFLP analysis of genetic variation among three natural populations of horseshoe crab Tachypleus tridentatus along Chinese coast

    Institute of Scientific and Technical Information of China (English)

    XU Qian; CHEN Fei; Paul K.S.SHIN; S.G.CHEUNG; CHEN Yan; KE Caihuan

    2011-01-01

    The AFLP (amplified fragment length polymorphism) technique was used to analyze and compare the genetic diversity of Tachypleus tridentatus from three south-eastern coastal sites of China (Pingtan, Hong Kong and Beihai). Eight pairs of primers generated 361 loci, including 285polymorphic loci. The ratio of polymorphic loci was 96.97%. Nei's genetic diversity index was 0.420 8and the Shannon information index was 0.607 5, both of which were higher than that reported for many other arthropods. These results show that the genetic diversity detected was mainly caused by individual differences within a population. Genetic distance showed that the rational division of the three geographic populations of T. tridentatus along the south-eastern coast of China was not significant, in which the genetic distance was not proportional to the geographic distance. All three horseshoe crab populations may belong to a large group, and had a high degree of genetic similarity.The high level of genetic diversity obtained from the present AFLP analysis may be due to the large effective population size of the species in Chinese waters.

  8. A propensity‐matched study of the effect of diabetes on the natural history of heart failure: variations by sex and age

    Science.gov (United States)

    Ahmed, Ali; Aban, Inmaculada B; Vaccarino, Viola; Lloyd‐Jones, Donald M; Goff, David C; Zhao, Jiannan; Love, Thomas E; Ritchie, Christine; Ovalle, Fernando; Gambassi, Giovanni; Dell'Italia, Louis J

    2007-01-01

    Background Poor prognosis in heart failure (HF) patients with diabetes is often attributed to increased co‐morbidity and advanced disease. Further, this effect may be worse in women. Objective To determine whether the effect of diabetes on outcomes and the sex‐related variation persisted in a propensity score‐matched HF population, and whether the sex‐related variation was a function of age. Methods Of the 7788 HF patients in the Digitalis Investigation Group trial, 2218 had a history of diabetes. Propensity score for diabetes was calculated for each patient using a non‐parsimonious logistic regression model incorporating all measured baseline covariates, and was used to match 2056 (93%) diabetic patients with 2056 non‐diabetic patients. Results All‐cause mortality occurred in 135 (25%) and 216 (39%) women without and with diabetes (adjusted HR = 1.67; 95% CI = 1.34 to 2.08; p<0.001). Among men, 535 (36%) and 609 (41%) patients without and with diabetes died from all causes (adjusted HR = 1.21; 95% CI = 1.07 to 1.36; p = 0.002). Sex–diabetes interaction (overall adjusted p<0.001) was only significant in patients ⩾65 years (15% absolute risk increase in women; multivariable p for interaction = 0.005), but not in younger patients (2% increase in women; p for interaction = 0.173). Risk‐adjusted HR (95% CI) for all‐cause hospitalisation for women and men were 1.49 (1.28 to 1.72) and 1.21 (1.11 to 1.32), respectively, also with significant sex–diabetes interaction (p = 0.011). Conclusions Diabetes‐associated increases in morbidity and mortality in chronic HF were more pronounced in women, and theses sex‐related differences in outcomes were primarily observed in elderly patients. PMID:17488764

  9. Seasonal variation in nitrogen pools and 15N/13C natural abundances in different tissues of grassland plants

    Directory of Open Access Journals (Sweden)

    J. K. Schjoerring

    2011-12-01

    Full Text Available Seasonal changes in nitrogen (N pools, carbon (C content and natural abundance of 13C and 15N in different tissues of ryegrass plants were investigated in two intensively managed grassland fields in order to address their ammonia (NH3 exchange potential. Green leaves generally had the largest total N concentration followed by stems and inflorescences. Senescent leaves had the lowest N concentration, indicating N re-allocation. The seasonal pattern of the Γ value, i.e. the ratio between NH4+ and H+ concentrations, was similar for the various tissues of the ryegrass plants but the magnitude of Γ differed considerably among the different tissues. Green leaves and stems generally had substantially lower Γ values than senescent leaves and litter. Substantial peaks in Γ were observed during spring and summer in response to fertilization and grazing. These peaks were associated with high NH4+ rather than with low H+ concentrations. Peaks in Γ also appeared during the winter, coinciding with increasing δ15N values, indicating absorption of N derived from mineralization of soil organic matter. At the same time, δ13C values were declining, suggesting reduced photosynthesis and capacity for N assimilation. δ15N and δ13C values were more influenced by mean monthly temperature than by the accumulated monthly precipitation. In conclusion, ryegrass plants showed a clear seasonal pattern in N pools. Green leaves and stems of ryegrass plants generally seem to constitute a sink for NH3, while senescent leaves have a large potential for NH3 emission. However, management events such as fertilisation and grazing may create a high NH3 emission potential even in green plant parts. The obtained results provide input for future modelling of plant-atmosphere NH3 exchange.

  10. INTRASPECIFIC VARIATION OF THE GREEN TURTLE, Chelonia mydas (CHELONIIDAE, IN THE FORAGING AREA OF GORGONA NATURAL NATIONAL PARK (COLOMBIAN PACIFIC

    Directory of Open Access Journals (Sweden)

    LAURA SAMPSON

    2014-01-01

    Full Text Available RESUMEN Se comparó la distribución de tallas y condición corporal de los dos morfotipos conocidos de tortuga verde (Chelonia mydas en el área de forrajeo del Parque Nacional Natural Gorgona (PNNG en el Pacífico colombiano entre 2003 y 2012. Se tomaron medidas de largo recto de caparazón (LRC, largo curvo de caparazón (LCC, peso y condición corporal de 1.023 tortugas capturadas en los arrecifes del PNNG. Se capturaron más tortugas negras (n = 747 que amarillas (n = 276, todas juveniles. Las tortugas negras fueron significativamente más grandes y pesadas que las amarillas. El tamaño de reclutamiento a la zona nerítica fue de 40,0–49,9 cm para ambos morfotipos, pero hubo más tortugas amarillas que negras en este intervalo de tamaños, lo cual sugiere una variación en el patrón de reclutamiento. El índice de condición corporal de las tortugas amarillas fue significativamente más alto que el de las tortugas negras, lo cual podría indicar diferencias en la utilización de recursos. Con base en los resultados obtenidos, se sugiere que el PNNG podría funcionar como un área de reclutamiento para las tortugas amarillas, las cuales llegan más pequeñas a esta zona; y como parte de la ruta migratoria costera de las tortugas negras, las cuales llegan más grandes e incluso residen en esta localidad durante un lapso de tiempo desconocido.

  11. Short-term natural δ13C and δ18O variations in pools and fluxes in a beech forest: the transfer of isotopic signal from recent photosynthates to soil respired CO2

    Directory of Open Access Journals (Sweden)

    G. Matteucci

    2011-10-01

    Full Text Available The fate of photosynthetic products within the plant-soil continuum determines how long the reduced carbon resides within the ecosystem and when it returns back to the atmosphere in the form of respiratory CO2. We have tested the possibility of measuring natural variation in δ13C and δ18O to disentangle the potential times needed to transfer carbohydrates produced by photosynthesis down to trunk, roots and, in general, to belowground up to its further release in the form of soil respiration into the atmosphere in a beech (Fagus sylvatica forest. We have measured the variation in stable carbon and oxygen isotope compositions in plant material and in soil respired CO2 every three hours for three consecutive days. Possible steps and different signs of post-photosynthetic fractionation during carbon translocation were also identified. A 12 h-periodicity was observed for variation in δ13C in soluble sugars in the top crown leaves and it can be explained by starch day/night dynamics in synthesis and breakdown and by stomatal limitations under elevated vapour pressure deficits. Photosynthetic products were transported down the trunk and mixed with older carbon pools, therefore causing the dampening of the δ13C signal variation. The strongest periodicity of 24 h was found in δ13C in soil respiration indicating changes in root contribution to the total CO2 efflux. Other non-biological causes like diffusion fractionation and advection induced by gas withdrawn from the measurement chamber complicate data interpretation on this step of C transfer path. Nevertheless, it was possible to identify the speed of carbohydrates' translocation from the point of assimilation to the trunk breast height because leaf-imprinted enrichment of δ18O in soluble sugars was less modified along the downward transport and was well related to environmental parameters potentially linked to stomatal conductance. The speed of carbohydrates translocation from the site of

  12. Spatial variation of seed rain and seed banks in gaps of karst forest in the Maolan Nature Reserve, Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    Cuiling LONG; Shixiao YU

    2008-01-01

    Based on an investigation on gaps and non-gap stands of the Maolan National Karst Forest Nature Reserve, Guizhou Province, quantitative characteristics and dynamic changes of seed rain and seed banks in gaps were analyzed. The results show that the total amount of seed rain was 117.4 ± 32.6 seeds/m2 during the period of observation. The number of immature seeds was 56.3 ± 10.3 seeds/m2, that of mature damaged seeds was 15.7 ± 4.7 seeds/m2, and the number of mature germinated seeds was 45.4 ± 8.2 seeds/m2 It is suggested that the seed number is rich for gap regeneration. Seed rain in gaps has spatial and temporal heterogeneities which deeply affect regeneration patterns of gap plants. Along a gradient from the gap center to a non-gap stand, seed density in the litter layer, the number of species, and the Shannon-Wiener diversity index were gradually reduced, but these indices increased in the soil. The seed density in the gap center was 2415 ± 639 seeds/m2, near the gap center was 2218 ± 421 seeds/m2 and at the gap border area 1815 ± 311 seeds/m2. This shows that plants in gaps have good latent regenera-tion potential. In both gaps and non-gap stands, the Jaccard similarity index of seed in litter layer was the lar-gest, second largest at 5-10 cm soil depth, and the least at the 0-5 cm soil layer the index. The Jaccard index between the soil seed bank and the present plant community was large in the litter layer, but decreased with soil depth both in gaps and non-gap stands. The results show that soil seed banks are the main source of gap regeneration in the karst forests of Maolan and contribute significantly to gap regeneration.

  13. Microsatellite diversity and broad scale geographic structure in a model legume: building a set of nested core collection for studying naturally occurring variation in Medicago truncatula

    DEFF Research Database (Denmark)

    Ronfort, Joelle; Bataillon, Thomas; Santoni, Sylvain

    2006-01-01

    scheme. Conclusion The stratification inferred is discussed considering potential historical events like expansion, refuge history and admixture between neighbouring groups. Information on the allelic richness and the inferred population structure are used to build a nested core-collection. The set......Abstract               Acknowledgements References   Background Exploiting genetic diversity requires previous knowledge of the extent and structure of the variation occurring in a species. Such knowledge can in turn be used to build a core-collection, i.e. a subset of accessions that aim...... at representing the genetic diversity of this species with a minimum of repetitiveness. We investigate the patterns of genetic diversity and population structure in a collection of 346 inbred lines representing the breadth of naturally occurring diversity in the Legume plant model Medicago truncatula using 13...

  14. Natural variation of the amino-terminal glutamine-rich domain in Drosophila argonaute2 is not associated with developmental defects.

    Directory of Open Access Journals (Sweden)

    Daniel Hain

    Full Text Available The Drosophila argonaute2 (ago2 gene plays a major role in siRNA mediated RNA silencing pathways. Unlike mammalian Argonaute proteins, the Drosophila protein has an unusual amino-terminal domain made up largely of multiple copies of glutamine-rich repeats (GRRs. We report here that the ago2 locus produces an alternative transcript that encodes a putative short isoform without this amino-terminal domain. Several ago2 mutations previously reported to be null alleles only abolish expression of the long, GRR-containing isoform. Analysis of drop out (dop mutations had previously suggested that variations in GRR copy number result in defects in RNAi and embryonic development. However, we find that dop mutations genetically complement transcript-null alleles of ago2 and that ago2 alleles with variant GRR copy numbers support normal development. In addition, we show that the assembly of the central RNAi machinery, the RISC (RNA induced silencing complex, is unimpaired in embryos when GRR copy number is altered. In fact, we find that GRR copy number is highly variable in natural D. melanogaster populations as well as in laboratory strains. Finally, while many other insects share an extensive, glutamine-rich Ago2 amino-terminal domain, its primary sequence varies drastically between species. Our data indicate that GRR variation does not modulate an essential function of Ago2 and that the amino-terminal domain of Ago2 is subject to rapid evolution.

  15. Adult sex ratio variation : Implications for breeding system evolution

    NARCIS (Netherlands)

    Szekely, T.; Weissing, F. J.; Komdeur, J.

    2014-01-01

    Adult sex ratio (ASR) exhibits immense variation in nature, although neither the causes nor the implications of this variation are fully understood. According to theory, the ASR is expected to influence sex roles and breeding systems, as the rarer sex in the population has more potential partners to

  16. The global role of natural disaster fatalities in decision-making: statistics, trends and analysis from 116 years of disaster data compared to fatality rates from other causes

    Science.gov (United States)

    Daniell, James; Wenzel, Friedemann; McLennan, Amy; Daniell, Katherine; Kunz-Plapp, Tina; Khazai, Bijan; Schaefer, Andreas; Kunz, Michael; Girard, Trevor

    2016-04-01

    In this study, analysis is undertaken showing disaster fatalities trends from around the world using the CATDAT Natural Disaster and Socioeconomic Indicator databases from 1900-2015. Earthquakes have caused over 2.3 million fatalities since 1900; however absolute numbers of deaths caused by them have remained rather constant over time. However, floods have caused somewhere between 1.7 and 5.4 million fatalities, mostly in the earlier half of the 20th century (depending on the 1931 China floods). Storm and storm surges (ca. 1.3 million fatalities), on the other hand, have shown an opposite trend with increasing fatalities over the century (or a lack of records in the early 1900s). Earthquakes due to their sporadic nature, do not inspire investment pre-disaster. When looking at the investment in flood control vs. earthquakes, there is a marked difference in the total investment, which has resulted in a much larger reduction in fatalities. However, a key consideration for decision-makers in different countries around the world when choosing to implement disaster sensitive design is the risk of a natural disaster death, compared to other types of deaths in their country. The creation of empirical annualised ratios of earthquake, flood and storm fatalities from the year 1900 onwards vs. other methods of fatalities (cancer, diseases, accidents etc.) for each country using the CATDAT damaging natural disasters database is undertaken. On an annualised level, very few countries show earthquakes and other disaster types to be one of the highest probability methods for death. However, in particular years with large events, annual rates can easily exceed the total death count for a particular country. An example of this is Haiti, with the equivalent earthquake death rate in 2010 exceeding the total all-cause death rate in the country. Globally, fatality rates due to disasters are generally at least 1 order of magnitude lower than other causes such as heart disease. However, in

  17. A coastal cline in sodium accumulation in Arabidopsis thaliana is driven by natural variation of the sodium transporter AtHKT1;1.

    Directory of Open Access Journals (Sweden)

    Ivan Baxter

    2010-11-01

    Full Text Available The genetic model plant Arabidopsis thaliana, like many plant species, experiences a range of edaphic conditions across its natural habitat. Such heterogeneity may drive local adaptation, though the molecular genetic basis remains elusive. Here, we describe a study in which we used genome-wide association mapping, genetic complementation, and gene expression studies to identify cis-regulatory expression level polymorphisms at the AtHKT1;1 locus, encoding a known sodium (Na(+ transporter, as being a major factor controlling natural variation in leaf Na(+ accumulation capacity across the global A. thaliana population. A weak allele of AtHKT1;1 that drives elevated leaf Na(+ in this population has been previously linked to elevated salinity tolerance. Inspection of the geographical distribution of this allele revealed its significant enrichment in populations associated with the coast and saline soils in Europe. The fixation of this weak AtHKT1;1 allele in these populations is genetic evidence supporting local adaptation to these potentially saline impacted environments.

  18. Occupational and public health considerations for work-hour limitations policy regarding public health workers during response to natural and human-caused disasters.

    Science.gov (United States)

    Berkowitz, Murray R

    2012-01-01

    This article examines the occupational health considerations that might impact the health and wellbeing of public health workers during responses to natural (eg, floods and hurricanes) and human-caused (eg, terrorism, war, and shootings) disasters. There are a number of articles in the medical literature that argue the impact of how working long hours by house staff physicians, nurses, and first-responders may pose health and safety concerns regarding the patients being treated. The question examined here is how working long hours may pose health and/or safety concerns for the public health workers themselves, as well as to those in the communities they serve. The health problems related to sleep deprivation are reviewed. Current policies and legislations regarding work-hour limitations are examined. Policy implications are discussed.

  19. The Adaptive Change of HLA-DRB1 Allele Frequencies Caused by Natural Selection in a Mongolian Population That Migrated to the South of China.

    Directory of Open Access Journals (Sweden)

    Hao Sun

    Full Text Available Pathogen-driven balancing selection determines the richness of human leukocyte antigen (HLA alleles. Changes in the pathogen spectrum may cause corresponding changes in HLA loci. Approximately 700 years ago, a Mongolian population moved from the north of China to the Yunnan region in the south of China. The pathogen spectrum in the south of China differs from that in the north. In this study, changes in the HLA genes in the Yunnan Mongolian population, as well as the underlying mechanism, were investigated. A sequence-based typing method (SBT was used to genotype HLA-DRB1 in 470 individuals from two Mongolian populations and another five ethnic groups. Meanwhile, 10 autosomal short tandem repeats (STRs were genotyped to assess the influence of genetic background on HLA-DRB1 frequencies. The frequencies of certain alleles changed significantly in the Mongolian population that migrated to Yunnan. For example, DRB1*12:02:01 increased from 6.1% to 35.4%. STR analysis excluded the possibility of a recent bottleneck and indicated that 50% of the genetic consistency between northern and southern Mongolians; Tajima's D value for HLA-DRB1 exon2 and dN/dS analysis showed that the HLA-DRB1 genes in both Mongolian populations were under balancing selection. However, the sites under natural selection changed. We proposed that the dramatically change of HLA frequencies in southern Mongolian was caused by a combination of inter-population gene flow and natural selection. Certain diseases specific to the south of China, such as malaria, may be the driving force behind the enhanced DRB1*12:02:01 frequency.

  20. Evidence for modifier genes that enhance the effect of the Pax-3 mutation, splotch-delayed (Sp{sup d}), on facial morphology: A model for studying the causes of variation of Waardenburg syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, R.W.; Morell, R.; Friedman, T.B. [Michigan State Univ., East Lansing, MI (United States)] [and others

    1994-09-01

    Waardenburg syndrome type I (WS1) is caused by autosomal dominant mutations of the gene coding for the PAX3 transcription factor. These mutations have variable penetrance and expressivity within and between families where they cause hypopigmentation, deafness and facially dysmorphic features. It has been suspected that changes of penetrance and expressivity in WS1 mutations are caused by familial variation in other loci which interact with or modify the expression of the PAX3 locus. Splotch mutations (Sp, Sp{sup d}, etc.) are the mouse homologs of WS1 mutations. Mutations in Pax-3 were first used to predict the map position and function of WS1 mutations. We now present morphometric evidence for alleles of modifier genes, originating from Mus spretus and segregating in an F{sub 1} backcross with Mus musculus, that modify the effects of Sp{sup d} on the structure of mouse facial bones. Variation caused by these mouse genes are precisely homologous to the familial variation we see in dystopia canthorum, the principal diagnostic feature of Waardenburg syndrome type I. The mouse modifier genes of Pax-3 identified by this analysis are now being mapped as a first step towards positional cloning human PAX3 modifier genes.

  1. Silicon limitation on primary production and its destiny in Jiaozhou Bay, China Ⅷ: The variation of atmospheric carbon caused by both phytoplankton and human

    Institute of Scientific and Technical Information of China (English)

    杨东方; 苗振清; 石强; 陈豫; 陈国光

    2010-01-01

    Statistical analysis on data collected in the Jiaozhou Bay (Shandong, China) from May 1991 to February 1994 and those collected in Hawaii from March 1958 to December 2007 shows dynamic and cyclic changes in atmospheric carbon in the Northern Pacific Ocean (NPO), as well as the variation in space-time distribution of phytoplankton primary production and atmospheric carbon in the study regions. The study indicates that the human beings have imposed an important impact on the changing trends of the atmospheric...

  2. Population dynamics of sea ducks: using models to understand the causes, consequences, evolution, and management of variation in life history characteristics

    Science.gov (United States)

    Flint, Paul L.

    2015-01-01

    In this chapter, I explore population dynamics of sea ducks by developing population models. In determining which life history characteristics had the greatest influence on future population dynamics, adult female survival consistently had the highest sensitivity and elasticity and this result was robust across a wide range of life history parameter values. Conversely, retrospective models consistently found that the majority of annual variation in lambda was associate with variation in productivity. Stochastic models that are base on process variation and incorporate correlations among life history parameters are the most useful for visualizing the probability of achieving a desired management outcome. Effective management targets both the mean and the variance parameters and takes advantage of correlations among life history parameters. Example models demonstrate that sea duck species can achieve equal fitness using a variety of survival and productivity combinations. Sea duck populations will tend to have long time largest in terms of responding to management actions. Understanding the role of density-dependent population regulation is critical for effective sea duck management and conservation.

  3. Large-scale genetic variation of the symbiosis-required megaplasmid pSymA revealed by comparative genomic analysis of Sinorhizobium meliloti natural strains

    Directory of Open Access Journals (Sweden)

    Landry Christian R

    2005-11-01

    Full Text Available Abstract Background Sinorhizobium meliloti is a soil bacterium that forms nitrogen-fixing nodules on the roots of leguminous plants such as alfalfa (Medicago sativa. This species occupies different ecological niches, being present as a free-living soil bacterium and as a symbiont of plant root nodules. The genome of the type strain Rm 1021 contains one chromosome and two megaplasmids for a total genome size of 6 Mb. We applied comparative genomic hybridisation (CGH on an oligonucleotide microarrays to estimate genetic variation at the genomic level in four natural strains, two isolated from Italian agricultural soil and two from desert soil in the Aral Sea region. Results From 4.6 to 5.7 percent of the genes showed a pattern of hybridisation concordant with deletion, nucleotide divergence or ORF duplication when compared to the type strain Rm 1021. A large number of these polymorphisms were confirmed by sequencing and Southern blot. A statistically significant fraction of these variable genes was found on the pSymA megaplasmid and grouped in clusters. These variable genes were found to be mainly transposases or genes with unknown function. Conclusion The obtained results allow to conclude that the symbiosis-required megaplasmid pSymA can be considered the major hot-spot for intra-specific differentiation in S. meliloti.

  4. Seasonal variation in species composition and abundance of demersal fish and invertebrates in a Seagrass Natural Reserve on the eastern coast of the Shandong Peninsula, China

    Science.gov (United States)

    Xu, Qiang; Guo, Dong; Zhang, Peidong; Zhang, Xiumei; Li, Wentao; Wu, Zhongxin

    2016-03-01

    Seagrass habitats are structurally complex ecosystems, which support high productivity and biodiversity. In temperate systems the density of seagrass may change seasonally, and this may influence the associated fish and invertebrate community. Little is known about the role of seagrass beds as possible nursery areas for fish and invertebrates in China. To study the functioning of a seagrass habitat in northern China, demersal fish and invertebrates were collected monthly using traps, from February 2009 to January 2010. The density, leaf length and biomass of the dominant seagrass Zostera marina and water temperature were also measured. The study was conducted in a Seagrass Natural Reserve (SNR) on the eastern coast of the Shandong Peninsula, China. A total of 22 fish species and five invertebrate species were recorded over the year. The dominant fish species were Synechogobius ommaturus, Sebastes schlegelii, Pholis fangi, Pagrus major and Hexagrammos otakii and these species accounted for 87% of the total number of fish. The dominant invertebrate species were Charybdis japonica and Octopus variabilis and these accounted for 98% of the total abundance of invertebrates. There was high temporal variation in species composition and abundance. The peak number of fish species occurred in August-October 2009, while the number of individual fish and biomass was highest during November 2009. Invertebrate numbers and biomass was highest in March, April, July and September 2009. Temporal changes in species abundance of fishes and invertebrates corresponded with changes in the shoot density and leaf length of the seagrass, Zostera marina.

  5. Analysis of Natural Allelic Variation Controlling Arabiciopsis thaliana Seed Germinability in Response to Cold and Dark: Identification of Three Major Quantitative Trait Loci

    Institute of Scientific and Technical Information of China (English)

    Ping-Hong Meng; Audrey Macquet; Olivier Loudet; Annie Marion-Poll; Helen M.North

    2008-01-01

    Light and temperature are key external factors in the control of Arabidopsis thaliana seed germination and dormancy mechanisms. Perception and response to these stimuli have to ensure that seedling emergence and growth occur at the most advantageous time for correct establishment. Analysis of over 300 Arabidopsis accessions identified 14, from 12 different geographical locations, that were able to germinate to greater than 20% at 6℃ in the dark. This natural variation was exploited to identify genetic loci responsible for cold-tolerant, dark germination. A quantitative trait loci approach was used on recombinant inbred line progeny of a cross between Bay-0 and Shahdara. Six distinct quantitative trait loci were identified, three of which were major loci, each responsible for 17-25% of the phenotypic variability in this trait. Parental phenotypes indicated that the majority of the cold-tolerant, dark-germination characteristics are related to light responses. Validation of the three major loci using heterogeneous inbred families confirmed the feasibility of fine mapping and cloning the genes at the quantitative trait loci responsible for cold-tolerant, dark germination.

  6. Optimized Multi-Class Variational Model for Natural Image Segmentation%多类变分模型优化的自然图像分割方法

    Institute of Scientific and Technical Information of China (English)

    杨勇; 郭玲; 叶阳东; 周小佳

    2016-01-01

    针对自然图像中内容的多样性、复杂性以及随机性,若采用区域内部恒定聚类中心假设的CV(Chan-Vese)模型以及多类水平集模型,则难以有效刻画具有非线性、连续性变化的自然图像内容。该文通过对区域内部自由度调控的多变量学生-t概率密度分布描述,提出了多类非线性变分活动轮廓模型,它打破了区域内部恒定密度的约束。由于多类非线性变分活动轮廓模型缺乏区域外力,容易分割出离散、零碎的噪声区域,通过引入测地线区域外力约束项,能有效分割出区域间的光滑边界。针对多类变分模型的最小化问题是NP难问题,提出对多类变分活动轮廓模型进行离散化表达,然后构建对应的多层图割模型,并利用最大流/最小割优化方式快速求得全局近似最优解。实验表明,该文提出的分割方法能够准确地分割出多类非同质目标区域,且区域之间的边界光滑,视觉效果好。%The content of the natural image is diversity, complexity, and randomly, so that the nonlinear and continuity change of natural image cannot be described effectively by using the constant density assumption of regions in CV (Chan-Vese) model or multiphase level sets model. In this paper, we propose a multi-class nonlinear variational model that can break up the bottleneck of constant density through introducing the multivariable mixed student-t distribution. We further integrate the geodesic active model into the proposed model for getting some smoothly edges between regions. Additionally, the energy minimization of our proposed model is a NP hard problem, but, we can discretize the variational formulation into discretization form, and then find the approximate optimization solution through maximization flow/minimization cuts theory. Lastly, a large number of natural images are adopted for experiment comparison. The segmentation results demonstrate the

  7. Bringing the individual back to small-area variation studies: a multilevel analysis of all-cause mortality in Andalusia, Spain.

    Science.gov (United States)

    Merlo, Juan; Viciana-Fernández, Francisco J; Ramiro-Fariñas, Diego

    2012-10-01

    We performed a multilevel analysis (including individuals, households, census tracts, municipalities and provinces) on a 10% sample (N=230,978) from the Longitudinal Database of the Andalusian Population (LDAP). We aimed to investigate place effects on 8-year individual mortality risk. Moreover, besides calculating association (yielding odds ratios, ORs) between area socio-economic circumstances and individual risk, we wanted to estimate variance and clustering using the variance partition coefficient (VPC). We explicitly proclaim the relevance of considering general contextual effects (i.e. the degree to which the context, as a whole, affects individual variance in mortality risk) under at least two circumstances. The first of these concerns the interpretation of specific contextual effects (i.e. the association between a particular area characteristic and individual risk) obtained from multilevel regression analyses. The second involves the interpretation of geographical variance obtained from classic ecological spatial analyses. The so-called "ecological fallacy" apart, the lack of individual-level information renders geographical variance unrelated to the total individual variation and, therefore, difficult to interpret. Finally, we stress the importance of considering the familial household in multilevel analyses. We observed an association between percentage of people with a low educational level in the census tract and individual mortality risk (OR, highest v. lowest quintile=1.14; 95% confidence interval, CI 1.08-1.20). However, only a minor proportion of the total individual variance in the probability of dying was at the municipality (M) and census tract (CT) levels (VPC(M)=0.2% and VPC(CT)=0.3%). Conversely, the household (H) level appeared much more relevant (VPC(H)=18.6%) than the administrative geographical areas. Without considering general contextual effects, both multilevel analyses of specific contextual effects and ecological studies of small

  8. Natural variation in small molecule-induced TIR-NB-LRR signaling induces root growth arrest via EDS1- and PAD4-complexed R protein VICTR in Arabidopsis.

    Science.gov (United States)

    Kim, Tae-Houn; Kunz, Hans-Henning; Bhattacharjee, Saikat; Hauser, Felix; Park, Jiyoung; Engineer, Cawas; Liu, Amy; Ha, Tracy; Parker, Jane E; Gassmann, Walter; Schroeder, Julian I

    2012-12-01

    In a chemical genetics screen we identified the small-molecule [5-(3,4-dichlorophenyl)furan-2-yl]-piperidine-1-ylmethanethione (DFPM) that triggers rapid inhibition of early abscisic acid signal transduction via PHYTOALEXIN DEFICIENT4 (PAD4)- and ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1)-dependent immune signaling mechanisms. However, mechanisms upstream of EDS1 and PAD4 in DFPM-mediated signaling remain unknown. Here, we report that DFPM generates an Arabidopsis thaliana accession-specific root growth arrest in Columbia-0 (Col-0) plants. The genetic locus responsible for this natural variant, VICTR (VARIATION IN COMPOUND TRIGGERED ROOT growth response), encodes a TIR-NB-LRR (for Toll-Interleukin1 Receptor-nucleotide binding-Leucine-rich repeat) protein. Analyses of T-DNA insertion victr alleles showed that VICTR is necessary for DFPM-induced root growth arrest and inhibition of abscisic acid-induced stomatal closing. Transgenic expression of the Col-0 VICTR allele in DFPM-insensitive Arabidopsis accessions recapitulated the DFPM-induced root growth arrest. EDS1 and PAD4, both central regulators of basal resistance and effector-triggered immunity, as well as HSP90 chaperones and their cochaperones RAR1 and SGT1B, are required for the DFPM-induced root growth arrest. Salicylic acid and jasmonic acid signaling pathway components are dispensable. We further demonstrate that VICTR associates with EDS1 and PAD4 in a nuclear protein complex. These findings show a previously unexplored association between a TIR-NB-LRR protein and PAD4 and identify functions of plant immune signaling components in the regulation of root meristematic zone-targeted growth arrest.

  9. Genetic analysis of strawberry fruit aroma and identification of O-methyltransferase FaOMT as the locus controlling natural variation in mesifurane content.

    Science.gov (United States)

    Zorrilla-Fontanesi, Yasmín; Rambla, José-Luis; Cabeza, Amalia; Medina, Juan J; Sánchez-Sevilla, José F; Valpuesta, Victoriano; Botella, Miguel A; Granell, Antonio; Amaya, Iraida

    2012-06-01

    Improvement of strawberry (Fragaria × ananassa) fruit flavor is an important goal in breeding programs. To investigate genetic factors controlling this complex trait, a strawberry mapping population derived from genotype '1392', selected for its superior flavor, and '232' was profiled for volatile compounds over 4 years by headspace solid phase microextraction coupled to gas chromatography and mass spectrometry. More than 300 volatile compounds were detected, of which 87 were identified by comparison of mass spectrum and retention time to those of pure standards. Parental line '1392' displayed higher volatile levels than '232', and these and many other compounds with similar levels in both parents segregated in the progeny. Cluster analysis grouped the volatiles into distinct chemically related families and revealed a complex metabolic network underlying volatile production in strawberry fruit. Quantitative trait loci (QTL) detection was carried out over 3 years based on a double pseudo-testcross strategy. Seventy QTLs covering 48 different volatiles were detected, with several of them being stable over time and mapped as major QTLs. Loci controlling γ-decalactone and mesifurane content were mapped as qualitative traits. Using a candidate gene approach we have assigned genes that are likely responsible for several of the QTLs. As a proof of concept we show that one homoeolog of the O-methyltransferase gene (FaOMT) is the locus responsible for the natural variation of mesifurane content. Sequence analysis identified 30 bp in the promoter of this FaOMT homoeolog containing putative binding sites for basic/helix-loop-helix, MYB, and BZIP transcription factors. This polymorphism fully cosegregates with both the presence of mesifurane and the high expression of FaOMT during ripening.

  10. Explicit Teaching of the Nature of Science: A Study of the Impact of Two Variations of Explicit Instruction on Student Learning

    Science.gov (United States)

    Melville, Melissa

    The nature of science (NOS) is included in the National Science Education Standards and is described as a critical component in the development of scientifically literate students. Despite the significance of NOS in science education reform, research shows that many students continue to possess naive views of NOS. Explicit and reflective discussion as an instructional approach is relatively new in the field of research in NOS. When compared to other approaches, explicit instruction has been identified as more effective in promoting informed views of NOS, but gaps in student understanding still exist. The purpose of this study was to deepen the understanding of student learning of NOS through the investigation of two variations of explicit instruction. The subjects of the study were two seventh grade classes taught by the same classroom teacher. One class received explicit instruction of NOS within a plate tectonics unit and the second class received explicit instruction of NOS within a plate tectonics unit plus supporting activities focused on specific aspects of NOS. The instruction time for both classes was equalized and took place over a three week time period. The intention of this study was to see if the additional NOS activities helped students build a deeper understanding of NOS, or if a deep understanding could be formed solely through explicit and reflective discussion within content instruction. The results of the study showed that both classes progressed in their understanding of NOS. When the results of the two groups were compared, the group with the additional activities showed statistically significant gains on two of the four aspects of NOS assessed. These results suggest that the activities may have been valuable in promoting informed views, but more research is needed in this area.

  11. Studying Variation in Tunes

    NARCIS (Netherlands)

    Janssen, B.; van Kranenburg, P.

    2014-01-01

    Variation in music can be caused by different phenomena: conscious, creative manipulation of musical ideas; but also unconscious variation during music recall. It is the latter phenomenon that we wish to study: variation which occurs in oral transmission, in which a melody is taught without the help

  12. Low protein and high-energy diet: a possible natural cause of fatty liver hemorrhagic syndrome in caged White Leghorn laying hens.

    Science.gov (United States)

    Rozenboim, I; Mahato, J; Cohen, N A; Tirosh, O

    2016-03-01

    Fatty liver hemorrhagic syndrome (FLHS) is a metabolic condition of chicken and other birds caused by diverse nutritional, hormonal, environmental, and metabolic factors. Here we studied the effect of different diet composition on the induction of FLHS in single comb White Leghorn (WL) Hy-line laying hens. Seventy six (76) young WL (26 wks old) laying hens and 69 old hens (84 wks old) of the same breed were each divided into 4 treatment groups and provided 4 different diet treatments. The diet treatments included: control (C), 17.5% CP, 3.5% fat (F); normal protein, high fat (HF), 17.5% CP, 7% F; low protein, normal fat (LP), 13% CP, 3.5% F; and low protein, high fat (LPHF), 13% CP, 6.5% F. The diets containing high fat also had a higher ME of 3,000 kcal/kg of feed while the other 2 diets with normal fat had a regular lower amount of ME (2750 kcal/kg). Hen-day egg production (HDEP), ADFI, BW, egg weight, plasma enzymes indicating liver damage (alkaline phosphatase [ALP], aspartate aminotransferase [AST], gamma-glutamyl transferase [GGT]), liver and abdominal fat weight, liver color score (LCS), liver hemorrhagic score (LHS), liver fat content (LFC), liver histological examination, lipid peroxidation product in the liver, and genes indicating liver inflammation were evaluated. HDEP, ADFI, BW, and egg weight were significantly decreased in the LPHF diet group, while egg weight was also decreased in the LP diet group. In the young hens (LPHF group), ALP was found significantly higher at 30 d of diet treatment and was numerically higher throughout the experiment, while AST was significantly higher at 105 d of treatment. LCS, LHS, and LFC were significantly higher in young hens on the LPHF diet treatment. A liver histological examination shows more lipid vacuolization in the LPHF treatment diet. HF or LP alone had no significant effect on LFC, LHS, or LCS. We suggest that LP in the diet with higher ME from fat can be a possible natural cause for predisposing laying hens

  13. Investigating variations in background response in measurements of downhole natural gamma in a banded iron formation in the Pilbara, Western Australia

    Science.gov (United States)

    Murphy, Richard J.; Silversides, Katherine L.

    2017-02-01

    Measurements of downhole natural gamma radiation (NGR) provide important information about the location of shale or clay bands within stratigraphical sequences (e.g. in Banded Iron Formations; BIF). An ability to link NGR with other kinds of measurements that are acquired at greater spatial and stratigraphic resolution, such as those acquired by hyperspectral sensing, would open up possibilities for improving the resolution of boundary models. To do this, measurements made by NGR and hyperspectral sensing must be highly correlated and any inconsistencies between these data must be understood. Observations made from the literature and from NGR measurements made in a BIF formation of the Hamersley Group, Pilbara, Western Australia, suggest that NGR measurements in some sections of ore or BIF are elevated compared with other sections; laboratory assays of drill chips do not however suggest the presence of shale or clay. These apparent inconsistencies were investigated using hyperspectral measurements and chemical assays of rock cores in the laboratory and NGR measurements made in the field. We show that the patterns of elevated NGR were a consistent feature of the stratigraphy for this region. Comparison of NGR and Al2O3 made by laboratory assay and from hyperspectral sensing show that elevated NGR measurements were caused by Uranium which was not associated with the presence of shale. Neither Thorium nor Potassium contributed to the elevated gamma signal in the ore. Thorium was strongly correlated with Al2O3 and was found to provide the best indicator of the presence of shale in the stratigraphy.

  14. Drought-caused delay in nesting of Sonoran Desert birds and its facilitation of parasite- and predator-mediated variation in reproductive success

    Science.gov (United States)

    Chris McCreedy,; Van Riper, Charles

    2015-01-01

    As our understanding of climate change has increased, so has our awareness of the impacts of these changes on biotic systems. Climate models are nearly unanimous in their predictions for increased drought frequency in southwestern North America, and delays in nest initiation due to drought may influence nesting success and productivity for many Sonoran Desert bird species. In southeastern California and western Arizona in 2004–2009, we found negative correlations for 13 of 13 species between nest initiation date and rainfall accumulation during the preceding 4-month winter rainy season. Nesting was delayed more than 3 weeks for some species during extreme droughts in 2006 and 2007. During 2004–2009, we found a significant negative effect of nest initiation date on nest survival probability (β̂ = −0.031 ± 0.005 SE, P causes of nest failure, we conclude that the impacts of climate change–caused drought on annual reproductive output in the Sonoran Desert will be further compounded by parasitism and predation for Black-tailed Gnatcatchers and by predation for Verdins.

  15. A novel Ehrlichia genotype strain distinguished by the TRP36 gene naturally infects cattle in Brazil and causes clinical manifestations associated with ehrlichiosis.

    Science.gov (United States)

    Aguiar, Daniel M; Ziliani, Thayza F; Zhang, Xiaofeng; Melo, Andreia L T; Braga, Isis A; Witter, Rute; Freitas, Leodil C; Rondelli, André L H; Luis, Michele A; Sorte, Eveline C B; Jaune, Felipe W; Santarém, Vamilton A; Horta, Mauricio C; Pescador, Carolina A; Colodel, Edson M; Soares, Herbert S; Pacheco, Richard C; Onuma, Selma S M; Labruna, Marcelo B; McBride, Jere W

    2014-09-01

    A novel Ehrlichia genotype most closely related to E. canis was reported in North American cattle in 2010, and a similar agent was subsequently identified in the hemolymph of Brazilian Rhipicephalus (Boophilus) microplus ticks and isolated in 2012. The purpose of this study was to determine whether this or other novel ehrlichial agents naturally infect Brazilian cattle. Using PCR targeting the genus-conserved dsb gene, DNA from this novel ehrlichial agent in Brazilian cattle was detected. Attempts to isolate the organism in vitro were performed using DH82 cells, but morulae and ehrlichial DNA could only be detected for approximately one month. In order to further molecularly characterize the organism, PCR was performed using primers specific for multiple E. canis genes (dsb, rrs, and trp36). Sequence obtained from the conserved rrs and dsb genes demonstrated that the organism was 99-100% identical to the novel Ehrlichia genotypes previously reported in North American cattle (rrs gene) and Brazilian ticks (rrs and dsb genes). However, analysis of the trp36 gene revealed substantial strain diversity between these Ehrlichia genotypes strains, including divergent tandem repeat sequences. In order to obtain preliminary information on the potential pathogenicity of this ehrlichial agent and clinical course of infection, a calf was experimentally infected. The calf showed clinical signs of ehrlichiosis, including fever, depression, lethargy, thrombocytopenia, and morulae were observed in peripheral blood monocytes. This study reports a previously unrecognized disease-causing Ehrlichia sp. in Brazilian cattle that is consistent with the genotype previously described in North America cattle and ticks from Brazil. Hence, it is likely that this is the organism previously identified as Ehrlichia bovis in Brazil in 1982. Furthermore, we have concluded that strains of these Ehrlichia genotypes can be molecularly distinguished by the trp36 gene, which has been widely utilized to

  16. Does the use of gonadotropin-releasing hormone antagonists in natural IVF cycles for poor responder patients cause more harm than benefit?

    Science.gov (United States)

    Aksoy, Senai; Yakin, Kayhan; Seyhan, Ayse; Oktem, Ozgur; Alatas, Cengiz; Ata, Baris; Urman, Bulent

    2016-06-01

    Poor ovarian response to controlled ovarian stimulation (COS) is one of the most critical factors that substantially limits the success of assisted reproduction techniques (ARTs). Natural and modified natural cycle IVF are two options that could be considered as a last resort. Blocking gonadotropin-releasing hormone (GnRH) actions in the endometrium via GnRH receptor antagonism may have a negative impact on endometrial receptivity. We analysed IVF outcomes in 142 natural (n = 30) or modified natural (n = 112) IVF cycles performed in 82 women retrospectively. A significantly lower proportion of natural cycles reached follicular aspiration compared to modified natural cycles (56.7% vs. 85.7%, p numbers of IVF cycles ending in embryo transfer (26.7% vs. 44.6%) was not statistically significant between natural cycle and modified natural IVF cycles. Clinical pregnancy (6.7% vs. 7.1%) and live birth rates per initiated cycle (6.7% vs. 5.4%) were similar between the two groups. Notably, the implantation rate was slightly lower in modified natural cycles (16% vs. 25%, p > 0.05). There was a trend towards higher clinical pregnancy (25% vs. 16%) and live birth (25% vs. 12%) rates per embryo transfer in natural cycles compared to modified natural cycles, but the differences did not reach statistical significance.

  17. Diurnal variations in gas exchange and chlorophyll fluorescence in rice leaves: the cause for midday depression in CO2 photosynthetic rate

    Directory of Open Access Journals (Sweden)

    Debabrata Panda

    2011-12-01

    Full Text Available Gas exchange and chlorophyll fluorescence analysis were carried out to investigate the diurnal variations in photosynthesis in leaves of rice (Oryza sativa L.. Leaf CO2 photosynthetic rate (Pn showed a bimodal diurnal pattern and midday depression in Pn was observed at 13:00 h. Depression in Pn at midday was mostly attributed to stomatal limitation since the reduction in Pn was followed by the significant reduction in stomatal conductance (Gs. Midday depression in Pn was found to be associated with reversible inactivation of Photo-system II (PS II reaction centers and increase of photo-inhibition in response to high intensity as evidenced by the maximum efficiency of PS II (Fv/Fm decreased with increase of light intensity from 6:00 h to 16:00 h of a day. The minimal fluorescence (Fo gradually increased with increasing light intensity and reached its highest value at 13:00 h and on contrary the maximal fluorescence (Fm decreased and reached its lowest value at 13:00 h. Quantification of several chlorophyll fluorescence parameters (JIP-test like area above the fluorescence curve between Fo and Fm, phenomenological energy fluxes like electron transport per cross section (ETo/CS, active PS II reaction center per exited cross-section (RC/CSo and performance index (Pi were low in early morning, increasing with time and reaching a maximum at 9:00 h subsequently decreasing and reaching a minimum value at 13.00 h. On contrary the dissipation per cross-section (Dio/CS gradually increased with increasing light intensity and reached its highest value at 13:00 h. It is likely that PS II down-regulation and heat dissipation co-operated together to prevent the chloroplast from photo damage.

  18. Spatial variation in genetic diversity and natural selection on the thrombospondin-related adhesive protein locus of Plasmodium vivax (PvTRAP.

    Directory of Open Access Journals (Sweden)

    Rattiporn Kosuwin

    Full Text Available Thrombospondin-related adhesive protein (TRAP of malaria parasites is essential for sporozoite motility and invasions into mosquito's salivary gland and vertebrate's hepatocyte; thereby, it is a promising target for pre-erythrocytic vaccine. TRAP of Plasmodium vivax (PvTRAP exhibits sequence heterogeneity among isolates, an issue relevant to vaccine development. To gain insights into variation in the complete PvTRAP sequences of parasites in Thailand, 114 vivax malaria patients were recruited in 2006-2007 from 4 major endemic provinces bordering Myanmar (Tak in the northwest, n = 30 and Prachuap Khirikhan in the southwest, n = 25, Cambodia (Chanthaburi in the east, n = 29 and Malaysia (Yala and Narathiwat in the south, n = 30. In total, 26 amino acid substitutions were detected and 9 of which were novel, resulting in 44 distinct haplotypes. Haplotype and nucleotide diversities were lowest in southern P. vivax population while higher levels of diversities were observed in other populations. Evidences of positive selection on PvTRAP were demonstrated in domains II and IV and purifying selection in domains I, II and VI. Genetic differentiation was significant between each population except that between populations bordering Myanmar where transmigration was common. Regression analysis of pairwise linearized Fst and geographic distance suggests that P. vivax populations in Thailand have been isolated by distance. Sequence diversity of PvTRAP seems to be temporally stable over one decade in Tak province based on comparison of isolates collected in 1996 (n = 36 and 2006-2007. Besides natural selection, evidences of intragenic recombination have been supported in this study that could maintain and further generate diversity in this locus. It remains to be investigated whether amino acid substitutions in PvTRAP could influence host immune responses although several predicted variant T cell epitopes drastically altered the epitope

  19. Pseudo-asymmetry of cerebral blood flow in arterial spin labeling caused by unilateral fetal-type circle of Willis: Technical limitation or a way to better understanding physiological variations of cerebral perfusion and improving arterial spin labeling acquisition?

    Science.gov (United States)

    Law-Ye, B; Geerts, B; Galanaud, D; Dormont, D; Pyatigorskaya, N

    2016-09-01

    In the recently published article, "Unilateral fetal-type circle of Willis anatomy causes right-left asymmetry in cerebral blood flow with pseudo-continuous arterial spin labeling: A limitation of arterial spin labeling-based cerebral blood flow measurements?", it was shown by the method of arterial spin labeling (ASL) that unilateral fetal-type circle of Willis could induce variation of blood flow in cerebellar and posterior cerebral artery territory. We believe that the reported observation, rather than being a limitation, gives several interesting cues for understanding the ASL sequence. In this commentary, we formulate some suggestions regarding the use of ASL in clinical practice, discuss the potential causes of the above-mentioned pseudo-asymmetry and consider future improvements of the ASL technique.

  20. Variations in fatty acid compositions of the seed oil of Eruca sativa Mill. caused by different sowing periods and nitrogen forms

    Directory of Open Access Journals (Sweden)

    Atnan Ugur

    2010-01-01

    Full Text Available Background: Eruca is a native plant genus of the South Europe and central Asia where it has been cultivated since centuries. As the genus name implies, the oil is high in erucic acid. Materials and Methods: In this study, our aim was to investigate the effect of sowing periods (autumn and spring and three forms of the nitrogen-containing fertilizers (manure, calcium nitrate [Ca(NO 3 2 , 15.5% N], and ammonium sulphate [(NH 4 2 SO 4 , 21% N] on fatty acid compositions of the oils obtained from Eruca sativa Mill. seeds cultivated. All oils were obtained by maceration of the seeds with n-hexane at room temperature and converted to their methyl ester derivatives by trans-methylesterification reaction using boron-trifluorur (BF 3 . The fatty acid methyl esters (FAMEs in the oils were detected by capillary gas chromatography-mass spectrometry (GC-MS. Results: All the samples analyzed were found to contain quite high amounts of erucic acid ranging between 46.64-54.79%, followed by oleic (17.86-19.95%, palmitic (7.25-10.97%, linoleic (4.23-9.72%, and linolenic (1.98-3.01% acids. Conclusion: Our data pointed out that there is a statistically important alteration caused by these applications on the contents of only C12:0 and C14:0 found as the minor fatty acids, whereas no other fatty acids in the samples seemed to be affected by those criteria.

  1. Investigation of gamma-ray time shifts caused by capsule areal density variations in inertial confinement fusion experiments at the national ignition facility and the omega facility

    Science.gov (United States)

    Grafil, Elliot M.

    This thesis describes work on Cherenkov based gamma detectors used as diag- nostics at Inertial Confinement Fusion (ICF) facilities. The first part describes the calibration and commissioning of the Gamma Reaction History diagnostic which is a four cell Cherenkov detector array used to characterize the ICF implosion at the National Ignition Facility (NIF) by measuring the gamma rays generated during the fusion event. Two of the key metrics which the GRH measures are Gamma Bang Time (GBT) generated from the D(T,α)n thermonuclear burn and Ablator Peak Time (APT) caused by (n,n‧)gamma reactions in the surrounding capsule ablator. Simulations of ignition capsules predict that GBT and APT should be time synchronized. After GRH commissioning, the array was used during first year of NIF operation in the National Ignition Campaign. Contrary to expectations, time shifts between GBT and APT of order 10s of picoseconds were observed. In order to further investigate the possibility of these time shifts in view of testing both instrument and code credibility an ICF shot campaign at the smaller OMEGA facility in Rochester was devised. It was performed during two full shot days in April of 2013 and 2014 and confirmed in principle the viability of the Cherenkov detector approach but raised additional questions regarding the credibility of the simulation codes used to describe ICF experiments. Specifically the measurements show that the understanding of temporal behavior of GBT vs APT may not be properly modeled in the DRACO code used at OMEGA. In view of the OMEGA results which showed no time shifts between GBT and APT, the readout and timing synchronization system of the GRH setup at the NIF was reevaluated in the framework of this thesis. Motivated by the results, which highlighted the use of wrong optical fiber diameters and possible problems with the installed variable optical attenuators, the NIF equipment has been updated over the recent months and new timing tests will

  2. Natural and human causes of a flash flood in a small catchment (Rhodes Island, Greece) based on atmospheric forcing and runoff modeling techniques

    Science.gov (United States)

    Karalis, Sotirios; Katsafados, Petros; Karymbalis, Efthimios; Tsanakas, Konstantinos; Valkanou, Kanella

    2014-05-01

    This study investigates the natural (hydro-meteorological and geomorphological) and human induced factors responsible for a flash flood event that occurred on November 22nd, 2013 in a small ungauged catchment (covering an area of about 24km2) of Rhodes Island, Greece. The flash flooding killed four people and caused over â¬10 million worth of damages located mainly around the Kremasti village. In this study the reconstruction of this extreme hydro-meteorological event is attempted by using detailed spatiotemporal rainfall information, a physically based hydrological model (LISEM) and the 1D hydraulic model HEC-RAS. Furthermore, the human impacts, which are responsible for extreme flood discharge within the drainage basin, are recorded and mapped. The major meteorological feature of this event is associated with the passage of a cold front over SE Aegean Sea. The destructive flash flood was triggered by the extreme precipitation (almost 100 mm in 4 hours was recorded at the meteorological stations closest to the flooded area). An advanced nowcasting method is applied in order to provide high spatiotemporal distribution of the precipitation over the catchment area. OpenLisem (Limbourg Soil Erosion Model) is used as a runoff model for exploring the response of the catchment. It is a freeware raster model (based on PCRaster) that simulates the surface water and sediment balance for every gridcell. It is event based and has fine spatial and temporal resolution. The model is designed to simulate the effects of detailed land use changes or conservation measures on runoff, flooding and erosion during heavy rainstorms. Since OpenLISEM provides a detailed simulation of runoff processes, it is very demanding on input data (it requires a minimum of 24 maps depending on the input options). The PCRaster GIS functionality was used to derive the necessary data from the basic maps (DEM, land unit map and map of impermeable areas). The sources for the basic maps include geological

  3. Natural climate variations in historical times up to 10.000 years ago. Final report; Natuerliche Klimavariationen in historischen Zeiten bis 10.000 Jahre vor heute. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Mayr, C.; Graf, W.; Stichler, W.; Trimborn, P.

    2001-07-01

    The climatic information of the {sup 2}H and {sup 13}C concentrations of year rings of trees and plant material in general was investigated in climate chamber experiments, in which the influence of variations in the air temperature, relative humidity and water availability on the ratios between the stable isotopes of three different C{sub 3} species (Brassica olearacea, Eucalyptus globulus, Vicia faba) was analyzed. The findings show that the {delta}{sup 2}H values of the plant stems depend mainly on the isotope ratio of the water that was taken up, as well as on the {sup 2}H concentration of the leaf water, which in turn was influenced by the relative humidity of the ambient air. The {sup 13}C concentrations in the plant stems were influenced by all three parameters and had a negative correlation both with the relative humidity and with temperature. The water availability status was shown to have great influence on the {sup 13}C discrimination of the plant insofar as higher availability of water caused lower {sup 13}C concentrations. The results of the isotope analysis were proved by cyclic gas supply measurements. - Further, callibration studies were carried out with {delta}{sup 2}H and {delta}{sup 13}C time series of pine trees (Picea abies) in two sites in southern Germany (Schussbach, Klosterreichenbach). A methodology for establishing long isotope series from year-rings of subfossil oak trees was developed. Investigations on subfossil wood take account of the different components of the year-rings, i.e. early and late wood, and of the sample preparation method (raw wood, wood without soluble constitutents, and cellulose nitrate). Further, possibilities of recording and correcting {delta}{sup 2} growth trends are presented. Application of the methods resulted in steady and consistent {delta}{sup 13}C and {delta}{sup 2}H time series from partial sample series comprising different types of samples. The resulting time series cover the period from 8,230 BC for

  4. Variation tendency and analysis of cause of coral in Sanya%三亚珊瑚变化趋势及原因分析

    Institute of Scientific and Technical Information of China (English)

    吴钟解; 王道儒; 叶翠信; 李元超; 陈敏; 陈春华

    2012-01-01

    2006至2009年采用断面监测法对三亚蜈支洲、亚龙湾、大东海、鹿回头和西岛这5个区域的珊瑚进行了调查.结果显示:大东海、西岛、亚龙湾活珊瑚覆盖率呈现逐渐下降趋势,死珊瑚覆盖率则逐渐升高.鹿回头活珊瑚覆盖率处于较低水平,团块状珊瑚优势度高于枝状珊瑚,群落结构已经发生较大变化.分析表明长期的人类活动包括海洋工程、生活污水排放、旅游活动造成了这些区域的珊瑚退化,但这些区域新生珊瑚的补充量相对较高,说明珊瑚生长的自然环境基本没有改变.只要控制人类活动的影响,这些区域的珊瑚还具有恢复的可能性.蜈支洲活珊瑚覆盖率保持在较高水平,死珊瑚覆盖率较低,珊瑚补充量较高,分枝状珊瑚的优势度高,珊瑚群落结构相对稳定,这说明在保护的前提下开展可持续利用的生态旅游活动可以促进珊瑚礁的保护.%The survey was carried out for the monitoring coral in five different regions Centipede Island, Yalong Bay, the East China Sea, Luhuitou and West Island belong to Sanya from 2006 to 2009. The results showed that in the East China Sea, West Island and Yalong Bay, the coverage rates of the live coral were in a gradual downward trend, and the dead coral were increased gradually. In Luhuitou, the coverage of the live coral was at a relatively low level and the dominance of the agglomerate coral was higher than branched coral. Besides, the community structure has undergone significant changes. All of these showed the long-term human activities, including marine engineering, sewage discharge, tourism, resulted in degradation of the coral in these areas. However, the new coral recruitment was relatively high, which showed the basic natural environment for the coral growth has not changed. As long as the control of human activities was effective, the coral in these areas also there was a possibility of recovery. In Centipede Island

  5. Environmental Variation Generates Environmental Opportunist Pathogen Outbreaks.

    Science.gov (United States)

    Anttila, Jani; Kaitala, Veijo; Laakso, Jouni; Ruokolainen, Lasse

    2015-01-01

    Many socio-economically important pathogens persist and grow in the outside host environment and opportunistically invade host individuals. The environmental growth and opportunistic nature of these pathogens has received only little attention in epidemiology. Environmental reservoirs are, however, an important source of novel diseases. Thus, attempts to control these diseases require different approaches than in traditional epidemiology focusing on obligatory parasites. Conditions in the outside-host environment are prone to fluctuate over time. This variation is a potentially important driver of epidemiological dynamics and affect the evolution of novel diseases. Using a modelling approach combining the traditional SIRS models to environmental opportunist pathogens and environmental variability, we show that epidemiological dynamics of opportunist diseases are profoundly driven by the quality of environmental variability, such as the long-term predictability and magnitude of fluctuations. When comparing periodic and stochastic environmental factors, for a given variance, stochastic variation is more likely to cause outbreaks than periodic variation. This is due to the extreme values being further away from the mean. Moreover, the effects of variability depend on the underlying biology of the epidemiological system, and which part of the system is being affected. Variation in host susceptibility leads to more severe pathogen outbreaks than variation in pathogen growth rate in the environment. Positive correlation in variation on both targets can cancel the effect of variation altogether. Moreover, the severity of outbreaks is significantly reduced by increase in the duration of immunity. Uncovering these issues helps in understanding and controlling diseases caused by environmental pathogens.

  6. 变化环境下宣恩城区洪水变异及其成因分析%Flood variation and its cause analysis of Xuanen district under changing environment

    Institute of Scientific and Technical Information of China (English)

    李庆平; 李彬彬; 向延清; 谢平

    2015-01-01

    作为调蓄城市洪水的主要工程手段,城市上游水库和城市河道整治工程在保护沿岸居民不受侵害的同时,也改变了天然河道洪水槽蓄关系,再加上气候变化的影响,导致城市洪水的形成、演变及时空分布规律发生了变异。利用水文变异诊断系统和谢才-曼宁公式,分析了宣恩城区变化环境下洪水的变异形式、程度及其成因。结果发现:1956年-2010年面平均年最大月雨量序列在1998年发生了跳跃向下的中变异,说明气候变化影响下降雨呈减少趋势;宣恩站实测年最大日流量序列在1999年发生了跳跃向下的中变异,其洪峰流量呈减少趋势;流域洪水变异是气候变化和人类活动双重影响的结果,但前者影响仅为后者的41%;渠化改造导致宣恩站洪水流量减少,加剧了洪水变异,因此其防洪预警预案需要适应环境变化而进行调整。%As themain engineering means of controlling urban flood, river and upst ream reservoir regulations which protect people against flood disasters can change river channel storage and lead to the variations of the formation, evolution, and spatial and temporal distribution of urban flood due to climate change. In this st udy, hydrological variation diagnosis system and the formula of Ch zy-manning w ere used to determine the f lood variation form, degree, and causes of Xuanen dist rict under the changing en-vironment. The results show ed that(1) the average annual maximum monthly rainfall series from 1956 to 2010 have a moderat e variation w ith downw ard jump in 1998, which indicates t hat rainfall decreases under the changing environment;(2) the annual maximum daily flow series from 1962 to 2013 have a moderate variation with dow nw ard jump in 1999, which indicates that peak flow decreases; (3) The dual effects of climate change and human activities cause the flood variation, but the former effects are only 41% of the lat ter

  7. Tracing the Fate of Enhanced Organic Carbon Production during a Southern Ocean Fe Fertilization Experiment using Natural Variations in Carbon and Nitrogen Isotopic Composition

    Energy Technology Data Exchange (ETDEWEB)

    Altabet, M.A.

    2005-02-05

    This project focused on the N and C natural stable isotope response during SOFeX--a purposeful iron (Fe) addition experiment in the Fe limited Southern Ocean. One purpose of the study was to determine if relief of phytoplankton Fe stress would increase productivity sufficiently to enhance C export from surface to deep waters. We proposed that N and C stable isotopes would be useful for tracing this export. Iron was added to waters north and south of the Antarctic Polar Front in waters to the southwest of New Zealand. While both sites have high-nutrient, low chlorophyll conditions (HNLC) typical of Fe limitation, [SiO4] a required nutrient for diatoms was low at the northerly site and high at the southern location. The most extensive coverage occurred at the southern site. Here, FeSO4 was added four different times over an {approx}two week period. We found that: (1) Particulate organic nitrogen and carbon in the mixed layer increased by a factor of 2-3 in response to the Fe addition in the southern patch. (2) PN accumulation and NO3- drawdown were both 1-2 {micro}M during the occupation of the bloom, suggesting retention of particulates within the mixed layer of the southern patch. (3) {sub 15}N of PN and of NO{sub 3}{sup -} increased by 1-2{per_thousand} as [NO{sub 3}{sup -}] decreased, and there is a clear contrast between in- and out-patch stations with respect to particulate {sub 15}N. The isotopic fractionation factor for NO{sub 3}{sup -} was near 5-6{per_thousand} and appears to have been unaffected by Fe fertilization. In contrast, there was little change in {delta}{sup 13}C. (4) The > 54 {micro}m size fraction was typically lighter than the 1-54 {micro}m size fraction by about 0.5 {per_thousand} in {delta}{sup 13}C. In the south patch, this difference increased as the bloom progressed, and with increasing PN concentration. This result may have been caused by large chain-forming diatoms responded to the Fe addition and were likely isotopically lighter than

  8. 利用主动震源检测汶川地震余震引起的浅层波速变化%Using Active Source to Monitor Velocity Variation in Shallow Sediment Caused by the Wenchuan Earthquake

    Institute of Scientific and Technical Information of China (English)

    王伟涛; 王宝善; 葛洪魁; 陈颙; 袁松湧; 杨微; 李宜晋

    2009-01-01

    Seismic velocity near the fault zone is sensitive to the stress state within that area. After the Wenchuan earthquake, in order to monitor the velocity variation near fault zone, we conducted a field experiment in the north edge of Longmenshan fault, which lasted three weeks since July 6. In the experiment, an electric hammer was used as a repeatable seismic source and the seismic signals were recorded by eight short period seismometers composed of Guralp 40T sensor and Reftek 130B digitizer. The digitizers were timing continuously with GPS to reduce timing error. We calculate the travel time variation by the combination of absolute time and cross correlation time-delay measurement. The fractal velocity variations were obtained from travel time measurement. Two prominent drops up to~2 % were found, which were much more than the possible variation caused by barometric pressure change. We notice two moderate aftershocks with magnitude 4.9 and 4.7 occurring within 10km from the experiment field, when the two surface velocity drops showed up. We speculate the surface velocity drops may be caused by th