WorldWideScience

Sample records for causing natural variation

  1. Nature and causes of Quaternary climate variation of tropical South America

    Science.gov (United States)

    Baker, Paul A.; Fritz, Sherilyn C.

    2015-09-01

    This selective review of the Quaternary paleoclimate of the South American summer monsoon (SASM) domain presents viewpoints regarding a range of key issues in the field, many of which are unresolved and some of which are controversial. (1) El Niño-Southern Oscillation variability, while the most important global-scale mode of interannual climate variation, is insufficient to explain most of the variation of tropical South American climate observed in both the instrumental and the paleoclimate records. (2) Significant climate variation in tropical South America occurs on seasonal to orbital (i.e. multi-millennial) time scales as a result of sea-surface temperature (SST) variation and ocean-atmosphere interactions of the tropical Atlantic. (3) Decadal-scale climate variability, linked with this tropical Atlantic variability, has been a persistent characteristic of climate in tropical South America for at least the past half millennium, and likely, far beyond. (4) Centennial-to-millennial climate events in tropical South America were of longer duration and, perhaps, larger amplitude than any observed in the instrumental period, which is little more than a century long in tropical South America. These were superimposed upon both precession-paced insolation changes that caused significant variation in SASM precipitation and eccentricity-paced global glacial boundary conditions that caused significant changes in the tropical South American moisture balance. As a result, river sediment and water discharge increased and decreased across tropical South America, lake levels rose and fell, paleolakes arose and disappeared on the Altiplano, glaciers waxed and waned in the tropical Andes, and the tropical rainforest underwent significant changes in composition and extent. To further evaluate climate forcing over the last glacial cycle (˜125 ka), we developed a climate forcing model that combines summer insolation forcing and a proxy for North Atlantic SST forcing to

  2. 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.

  3. Natural 14C variations

    International Nuclear Information System (INIS)

    This thesis deals with the natural variations in the atmospheric 14C activity, their geophysical origin and their impact on radiocarbon dating. Studies confirm the idea that one is dealing with a mechanism of a certain regularity. The correlation between a 14C variation during the Little Ice Age and the absence of sunspots on the solar surface suggest the sun to be responsible for some kind of modulation of the galactic cosmic ray spectrum. The background of a changing natural 14C level is relevant when studying the antropogenic perturbation of the atmospheric 14C concentration by the addition of CO2 from fossil fuel combustion. The results presented point to a Suess effect over the past 150 years of about 20 per thousand, but also show a local dilution effect. If this local effect is present over large continental parts of the Northern Hemisphere this will put limits to the use of tree ring 14C measurements for testing carbon reservoir models. Finally the influence of 14C variations upon the interpretations of 14C dates for archaeological and geological purposes has been investigated. It is shown that care must be taken especially in the interpretation of highly accurate 14C data of material only covering a few years of growth. One geological example illustrates that 14C variations can easily be interpretated as alternating fast and slow rises of the sea level. (Auth.)

  4. 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. PMID:26927960

  5. Natural climate variations in a geological perspective

    International Nuclear Information System (INIS)

    The climate is constantly changing, and it has been changing throughout the geological history of the Earth. These natural changes have shown a variability with frequencies from millions of years to just a few hundreds or tens of years. Some of the variations have been rather dramatic - shifting from globally uniform and hot climates to regular ice ages - whereas other changes have been less spectacular. All natural climate variations have an impact on the physical and biological systems of the Earth - and on mankind and culture during the last hundred thousand years. In this chapter we shall discuss the natural climate changes that has taken place during the geological history of the Earth and comment on the impact of these changes on the cultural evolution of mankind with special emphasis on Greenland. (LN)

  6. Natural variation in casein composition of milk

    OpenAIRE

    van der Bijl, E.

    2014-01-01

    Bovine milk contains 3-4 % protein and almost 80% of the milk protein fraction consist of four caseins; αs1-casein, β-casein, αs2-casein and κ-casein. Most of the caseins in milk are assembled in casein micelles, which consist of several thousands of individual casein molecules and salts. The unique structure of casein micelles allows the delivery of large amounts of calcium and phosphate to the neonate. Considerable natural variation in casein content and composition e...

  7. Significant Causes and Effects of Variation Orders in Construction Projects

    Directory of Open Access Journals (Sweden)

    Aftab Hameed Memon

    2014-05-01

    Full Text Available Variation Order (VO is a common phenomenon in construction projects. It involves an amendment of the original scope of work as in the contract. VO is caused from various factors. Variations often cause disputes and dissatisfactions among the parties involved in construction projects. Thus, it is very important to control VOs in a construction project. For this, the first step is to uncover and understand the causes and effects of VO. Hence, the aim of this study is to determine the significant causes and effects of VO in construction projects. Data collection involved the survey with a structured questionnaire consisting of 18 causes and 9 effects of variation orders identified through comprehensive literature review. Survey was carried out among client representatives, consultants and contractors involved in handling projects of Malaysian Public Works Department (PWD known as Jabatan Kerja Raya Malaysia (JKR. A total of 101 completed questionnaire sets were collected against 200 questionnaires distributed among the practitioners. Collected questionnaires were analyzed with statistical software package SPSS and Average Index formula. The results of the study showed that in Malaysia’s JKR projects often variation orders are occurred; these VO’s are majorly caused because of unavailability of equipment, poor workmanship and design complexity. While most significant effects of VO on the projects are increased project cost, delay in completion and logistic delays. Early participation of professionals may be beneficial in reducing the occurrence of variations. Also, improved design and avoiding frequent design changes will be very effective in controlling the problem of variations.

  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. 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 in...... metabolomic networks. This suggests that cytoplasmic genomes must be included in any future analysis of natural variation....

  10. Studies on sulphur isotope variations in nature

    International Nuclear Information System (INIS)

    The variations of sulphur isotopes in natural compounds (and of oxygen isotopes in sulphates) provide a powerful method of investigation in various fields of earth sciences such as hydrology, geochemistry, geothermal exploration, volcanology, oceanography, sedimentology, ore formation, environmental sciences and others, although probably the method is not equally mature in all these fields, because of the inherent complexity and, sometimes, insufficient basic data. To review the current situation, and to identify trends of research and application of sulphur isotopes, the International Atomic Energy Agency held an Advisory Group Meeting on the Hydrology and Geochemistry of Sulphur Isotopes, which took place in Vienna at the IAEA Headquarters from 17 to 20 June 1985. Most of the papers presented at the meeting are included in this publication under the following titles: Isotopic composition of dissolved oceanic sulphate; Sulphur isotopes in the water of Lake Neusiedl, Austria; Relationships between the sulphur and oxygen isotope composition of dissolved sulphate; Sulphur and sulphate-oxygen isotopes in New Zealand geothermal systems and volcanic discharges; Isotopic composition and origin of sulphur compounds in groundwaters and brines in the Po Valley (northern Italy); Two case studies on the origin of aqueous sulphate in deep crystalline rocks; Sulphur and oxygen isotopic compositions of groundwater - and sabkha - sulphate in the Middle East; Radiolytic oxidation of sulphides and geochemical behaviour of sulphur isotopes in uranium deposits; On bias in 34S/32S data obtained using SO2 gas in mass spectrometry; Sulphur isotope analyses of trace sulphide and sulphate in various materials using Kiba reagent. Refs, figs and tabs

  11. Numerical studies of HF Doppler variations caused by ionospheric disturbances

    Science.gov (United States)

    Takefu, M.; Hiroshige, N.

    HF Doppler variations caused by ionospheric disturbances are studied using an ionosphere model containing sinusoidal traveling electron density fluctuations. The present study uses a more realistic ionosphere model and a more accurate numerical method than previous works using corrugated specular reflector models. The study gives a clue to estimate the TID-associated fluctuations of ionospheric electron density by means of HF Doppler measurements. It is shown that some kinds of characteristic HF Doppler traces result depending on the wavelength of the disturbance and its traveling direction. Numerical results suggest that more or less 5 percent of the background electron density can explain most of the quasi-periodic variations on the observed HF Doppler records.

  12. Causes of Forbush decreases and other cosmic ray variations

    International Nuclear Information System (INIS)

    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 γ. 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

  13. 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

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

    OpenAIRE

    Tabachnick, Walter J.

    2013-01-01

    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 compris...

  15. Asymmetric Information in Vietnamese Enterprises: Nature, Cause and Consequence

    Directory of Open Access Journals (Sweden)

    Thanh Tu Phan

    2014-02-01

    Full Text Available This study attempts to apply the agency theory in the context of Vietnam by analyzing the nature and causes of information transparency problem in Vietnamese enterprises, particularly the listed ones. We consider that the nature of this problem come from the contradictory interests between principal and agent; its main cause is the asymmetric information between the parties involved, which is favored in the context of separation between the business ownership (of principal and control (of agent. Profiting this lack of information transparency, the agents shall show their opportunism in seeking their self-interest, thus causing short-term damage in profit and long-term damage in value of the enterprise. To solve this problem, it is necessary that all parties should participate to the management and control of the enterprise on the basis of faithfulness and co-operation.

  16. Limits to natural variation: implications for systemic management

    Directory of Open Access Journals (Sweden)

    Fowler, C. W.

    2002-12-01

    Full Text Available Collectively, the tenets and principles of management emphasize the importance of recognizing and understanding limits. These tenets require the demonstration, measurement and practical use of information about limits to natural variation. It is important to identify limits so as not to incur the risks and loss of integrity when limits are exceeded. Thus, by managing within natural limits, humans (managers simultaneously can achieve sustainability and minimize risk, as well as account for complexity. This is at the heart of systemic management. Systemic management embodies the basic tenets of management. One tenet requires that management ensure that nothing exceed the limits observed in its natural variation. This tenet is based on the principle that variation is constrained by a variety of limiting factors, many of which involve risks. Another tenet of management requires that such factors be considered simultaneously, exhaustively, and in proportion to their relative importance. These factors, in combination, make up the complexity that managers are required to consider in applying the basic principles of management. This combination of elements is reflected in observed limits to natural variation that account for each factor and its relative importance. This paper summarizes conclusions from the literature that has addressed the concept of limits to natural variation, especially in regard to management. It describes: 1. How such limits are inherent to complex systems; 2. How limits have been recognized to be important to the process of management; 3. How they can be used in management. The inherent limits include both those set by the context in which systems occur (extrinsic factors as well as those set by the components and processes within systems (intrinsic factors. This paper shows that information about limits is of utility in guiding human action to fit humans within the normal range of natural variation. This is part of systemic

  17. 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.

  18. 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.

  19. Causes of variation in growth rate of reindeer calves

    OpenAIRE

    C.J. Petersson; DANELL, B.

    1993-01-01

    Weights of individual reindeer calves were registered on 3 or 4 occasions from the July roundup to the last slaughter roundup in January during each of four consecutive years (1986 to 1989). The observations were made in a tagged herd located in the southern part of the reindeer area in Sweden (63°N, 12°E). A total of 10 400 live-weight measurements were made, and the relationship between pre-slaughter weight and carcass weight was estimated using data from 109 individuals. Variation ...

  20. The Variation in Teachers' Grading Practices: Causes and Consequences.

    Science.gov (United States)

    Bonesronning, Hans

    1999-01-01

    Discusses causes and consequences of teachers' grading practices, which vary greatly among Norwegian uppersecondary schools. Introduces an alternative to easy grading, in which rent-seeking students allocate time to affect the teacher's grading. Shows that teacher's grading is systematically associated with teacher characteristics. Hard grading…

  1. 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.

  2. Spatial variation of sediment deposition in the Hudson River - a detailed inventory and potential causes (Invited)

    Science.gov (United States)

    Nitsche, F. O.; Kenna, T. C.

    2010-12-01

    Sediment deposition in urban estuaries is controlled by the interaction of human modifications and natural factors that include tides, fresh water inputs, bed morphology, sediment supply, and hydrodynamics. A key element of managing these estuaries is detailed understanding of sediment deposition and its driving processes. Using a combination of geophysical and geochemical analysis we establish a detailed inventory of 20 century deposition for most of the mud-dominated sections of the Hudson River. These data show variations between different segments of the Hudson River as well as strong local variations within each section, with depositional settings ranging from erosional to those accumulating at ~10 mm/year. Our work indicates that 170,000 - 250,000 metric tons of sediment are deposited annually in the areas studied, which is a significant portion of the estimated total annual sediment load of ~700,000 - 800,000 metric tons. This also suggests that some of the accumulated sediments are re-mobilized, e.g. during major storms. The observed patterns of deposition/erosion are primarily caused by natural conditions, but, in some parts, they are strongly influenced by human modifications of the estuary, such as dredging. In addition to improving our understanding of the sediment dynamic of the Hudson River, the observed distribution of sediment deposition is also an indicator for the occurrence of contaminants including heavy metals and PCB’s and thus a valuable tool for management decisions.

  3. Causes of variation in biotic interaction strength and phenotypic selection along an altitudinal gradient.

    Science.gov (United States)

    Mezquida, Eduardo T; Benkman, Craig W

    2014-06-01

    Understanding the causes of variation in biotic interaction strength and phenotypic selection remains one of the outstanding goals of evolutionary ecology. Here we examine the variation in strength of interactions between two seed predators, common crossbills (Loxia curvirostra) and European red squirrels (Sciurus vulgaris), and mountain pine (Pinus uncinata) at and below tree limit in the Pyrenees, and how this translates into phenotypic selection. Seed predation by crossbills increased whereas seed predation by squirrels decreased with increasing elevation and as the canopy became more open. Overall, seed predation by crossbills averaged about twice that by squirrels, and the intensity of selection exerted by crossbills averaged between 2.6 and 7.5 times greater than by squirrels. The higher levels of seed predation by crossbills than squirrels were related to the relatively open nature of most of the forests, and the higher intensity of selection exerted by crossbills resulted from their higher levels of seed predation. However, most of the differences in selection intensity between crossbills and squirrels were the result of habitat features having a greater effect on the foraging behavior of squirrels than of crossbills, causing selection to be much lower for squirrels than for crossbills. PMID:24593660

  4. Natural enemies drive geographic variation in plant defenses

    DEFF Research Database (Denmark)

    Zuest, Tobias; Heichinger, Christian; Grossniklaus, Ueli;

    2012-01-01

    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 o...... 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.......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...

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

    OpenAIRE

    Wintermans, P.C.A.; Bakker, P.A.H.M.; Pieterse, C.M.J.

    2016-01-01

    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 Arab...

  6. 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.

  7. Genetic variations and miRNA-target interactions contribute to natural phenotypic variations in Populus.

    Science.gov (United States)

    Chen, Jinhui; Xie, Jianbo; Chen, Beibei; Quan, Mingyang; Li, Ying; Li, Bailian; Zhang, Deqiang

    2016-10-01

    Variation in regulatory factors, including microRNAs (miRNAs), contributes to variation in quantitative and complex traits. However, in plants, variants in miRNAs and their target genes that contribute to natural phenotypic variation, and the underlying regulatory networks, remain poorly characterized. We investigated the associations and interactions of single-nucleotide polymorphisms (SNPs) in miRNAs and their target genes with phenotypes in 435 individuals from a natural population of Populus. We used RNA-seq to identify 217 miRNAs differentially expressed in a tension wood system, and identified 1196 candidate target genes; degradome sequencing confirmed 60 of the target sites. In addition, 72 miRNA-target pairs showed significant co-expression. Gene ontology (GO) term analysis showed that most of the genes in the co-regulated pairs participate in biological regulation. Genome resequencing found 5383 common SNPs (frequency ≥ 0.05) in 139 miRNAs and 31 037 SNPs in 819 target genes. Single-SNP association analyses identified 232 significant associations between wood traits (P ≤ 0.05) and SNPs in 102 miRNAs and 1387 associations with 478 target genes. Among these, 102 miRNA-target pairs associated with the same traits. Multi-SNP associations found 102 epistatic pairs associated with traits. Furthermore, a reconstructed regulatory network contained 12 significantly co-expressed pairs, including eight miRNAs and nine targets associated with traits. Lastly, both expression and genetic association showed that miR156i, miR156j, miR396a and miR6445b were involved in the formation of tension wood. This study shows that variants in miRNAs and target genes contribute to natural phenotypic variation and annotated roles and interactions of miRNAs and their target genes by genetic association analysis. PMID:27265357

  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. 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

  10. Natural epigenetic variation in bats and its role in evolution.

    Science.gov (United States)

    Liu, Sen; Sun, Keping; Jiang, Tinglei; Feng, Jiang

    2015-01-01

    When facing the challenges of environmental change, such as habitat fragmentation, organisms have to adjust their phenotype to adapt to various environmental stresses. Recent studies show that epigenetic modifications could mediate environmentally induced phenotypic variation, and this epigenetic variance could be inherited by future generations, indicating that epigenetic processes have potential evolutionary effects. Bats living in diverse environments show geographic variations in phenotype, and the females usually have natal philopatry, presenting an opportunity to explore how environments shape epigenetic marks on the genome and the evolutionary potential of epigenetic variance in bat populations for adaptation. We have explored the natural epigenetic diversity and structure of female populations of the great roundleaf bat (Hipposideros armiger), the least horseshoe bat (Rhinolophus pusillus) and the eastern bent-winged bat (Miniopterus fuliginosus) using a methylation-sensitive amplified polymorphism technique. We have also estimated the effects of genetic variance and ecological variables on epigenetic diversification. All three bat species have a low level of genomic DNA methylation and extensive epigenetic diversity that exceeds the corresponding genetic variance. DNA sequence divergence, epigenetic drift and environmental variables contribute to the epigenetic diversities of each species. Environment-induced epigenetic variation may be inherited as a result of both mitosis and meiosis, and their potential roles in evolution for bat populations are also discussed in this review. PMID:25568456

  11. Distribution of polychaete assemblage in relation to natural environmental variation and anthropogenic stress

    Science.gov (United States)

    Zan, Xiaoxiao; Zhang, Chongliang; Xu, Binduo; Xue, Ying; Ren, Yiping

    2015-08-01

    Polychaete are diverse species of the soft-bottom community, and are often used as indicators in environment monitoring programs. However, the effects of anthropogenic activities and natural environmental variation on polychaete assemblage are rarely addressed. The goals of this study are to identify the effects of natural environmental variation and anthropogenic stress on polychaete assemblage, and to explore the relationship between the polychaete assemblage structure and anthropogenic stress without considering the natural environmental variation. Based on the data collected from the surveys conducted in the tidal flat of Jiaozhou Bay, the relationship between polychaete assemblage structure and environmental variables was determined using multivariate statistical methods including hierarchical cluster analysis, multidimensional scaling (MDS) and canonical correspondence analysis (CCA). The results showed that the polychaete assemblage was dominated by two species, Amphictene japonica and Heteromastus filiformis, and could be divided into two subgroups characterized by high and low species abundance. CCA illustrated that the natural environmental variables including water temperature and the distance from coast had primary effects on the polychaete assemblage structure; while stress of contaminants, such as As and Hg, had the secondary influences; and stress from the aquacultured species, mainly Ruditapes philippinarum, had a limited effect. Colinearity between the natural environmental variables and anthropogenic stress variables caused a critical divergence in the interpretation of CCA results, which highlighted the risk of a lack of information in environment assessment. Glycinde gurjanovae, Sternaspis scutata and Eulalia bilineata may serve as the `contamination indicators', which need to be confirmed in future studies.

  12. Impact on Nonlinear Vertical Variation of GNSS Reference Stations Caused by Thermal Expansion

    Directory of Open Access Journals (Sweden)

    JIANG Weiping

    2015-05-01

    Full Text Available Thermal expansion of GPS monuments and nearby bedrock could result in vertical changes in the coordinate time series of GNSS reference stations. In this paper, an improved method was developed to compute the magnitude of vertical variations caused by thermal expansion. Firstly, we calculated the effect on GPS monument and bedrock caused by thermal expansion based on land surface temperature data of GNSS reference stations and thermal expansion model. Secondly, we estimated the circular frequencies, amplitudes and phases using the method of least squares fitting instead of the current method which estimated only the amplitudes and phases information. Finally, we studied the periodic characteristics of the vertical variations caused by our modified thermal expansion model. Through analyzing the results of 9 representative IGS stations, we concluded that thermal expansion of GPS monuments and nearby bedrock could result in vertical variations of GNSS stations. The maximum variations could reach up to 0.57 mm and 1.85 mm at these stations respectively. The vertical variation caused by thermal expansion exhibited both annual and semiannual characteristics, which could explain 11.2% and 3.3% of the total annual and semi-annual variations in the up component of the coordinate time series respectively, and the magnitudes became larger with the increasing of their latitudes. Meanwhile, the amplitudes of the annual variations were much larger than that of the semi-annual variations. Meanwhile, some other small period (about 51 days was also detected at some of these stations. In addition, we chose 107 IGS reference stations and computed the annual amplitudes and phases caused by thermal expansion of all these stations based on the method aforesaid. The results show that the maximum annual amplitude can reach to 3.3 mm, and their magnitudes show positive correlation with their latitudes prominently.

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

    Directory of Open Access Journals (Sweden)

    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

  14. Extensive Natural Variation in Arabidopsis Seed Mucilage Structure

    Directory of Open Access Journals (Sweden)

    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. Extensive Natural Variation in Arabidopsis Seed Mucilage Structure

    Science.gov (United States)

    Voiniciuc, Cătălin; Zimmermann, Eva; Schmidt, Maximilian Heinrich-Wilhelm; Günl, Markus; Fu, Lanbao; North, Helen M.; Usadel, Björn

    2016-01-01

    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 us to

  16. Variation in predator species abundance can cause variable selection pressure on warning signaling prey

    OpenAIRE

    Valkonen, Janne K.; Nokelainen, Ossi; Niskanen, Martti; Kilpimaa, Janne; Björklund, Mats; Mappes, Johanna

    2012-01-01

    Predation pressure is expected to drive visual warning signals to evolve toward conspicuousness. However, coloration of defended species varies tremendously and can at certain instances be considered as more camouflaged rather than conspicuous. Recent theoretical studies suggest that the variation in signal conspicuousness can be caused by variation (within or between species) in predators' willingness to attack defended prey or by the broadness of the predators' signal generalization. If som...

  17. Genetic variation in 5-hydroxytryptamine transporter expression causes adaptive changes in 5-HT4 receptor levels

    DEFF Research Database (Denmark)

    Jennings, Katie Ann; Licht, Cecilie Löe; Bruce, Aynsley;

    2012-01-01

    Genetic variation in 5-HT transporter (5-HTT) expression is a key risk factor for psychiatric disorder and has been linked to changes in the expression of certain 5-HT receptor subtypes. This study investigated the effect of variation in 5-HTT expression on 5-HT4 receptor levels in both 5-HTT kno......). Together, these findings suggest that variation in 5-HTT expression causes adaptive changes in 5-HT4 receptor levels which are directly linked to alterations in 5-HT availability.......Genetic variation in 5-HT transporter (5-HTT) expression is a key risk factor for psychiatric disorder and has been linked to changes in the expression of certain 5-HT receptor subtypes. This study investigated the effect of variation in 5-HTT expression on 5-HT4 receptor levels in both 5-HTT...

  18. Causes and consequences of intra-specific variation in vertebral number.

    Science.gov (United States)

    Tibblin, Petter; Berggren, Hanna; Nordahl, Oscar; Larsson, Per; Forsman, Anders

    2016-01-01

    Intraspecific variation in vertebral number is taxonomically widespread. Much scientific attention has been directed towards understanding patterns of variation in vertebral number among individuals and between populations, particularly across large spatial scales and in structured environments. However, the relative role of genes, plasticity, selection, and drift as drivers of individual variation and population differentiation remains unknown for most systems. Here, we report on patterns, causes and consequences of variation in vertebral number among and within sympatric subpopulations of pike (Esox lucius). Vertebral number differed among subpopulations, and common garden experiments indicated that this reflected genetic differences. A QST-FST comparison suggested that population differences represented local adaptations driven by divergent selection. Associations with fitness traits further indicated that vertebral counts were influenced both by stabilizing and directional selection within populations. Overall, our study enhances the understanding of adaptive variation, which is critical for the maintenance of intraspecific diversity and species conservation. PMID:27210072

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

    Directory of Open Access Journals (Sweden)

    LouisD.Matzel

    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.

  20. Extensive cotransformation of natural variation into chromosomes of naturally competent Haemophilus influenzae.

    Science.gov (United States)

    Mell, Joshua Chang; Lee, Jae Yun; Firme, Marlo; Sinha, Sunita; Redfield, Rosemary J

    2014-04-01

    Naturally competent bacterial species actively take up environmental DNA and can incorporate it into their chromosomes by homologous recombination. This can bring genetic variation from environmental DNA to recipient chromosomes, often in multiple long "donor" segments. Here, we report the results of genome sequencing 96 colonies of a laboratory Haemophilus influenzae strain, which had been experimentally transformed by DNA from a diverged clinical isolate. Donor segments averaged 6.9 kb (spanning several genes) and were clustered into recombination tracts of ~19.5 kb. Individual colonies had replaced from 0.1 to 3.2% of their chromosomes, and ~1/3 of all donor-specific single-nucleotide variants were present in at least one recombinant. We found that nucleotide divergence did not obviously limit the locations of recombination tracts, although there were small but significant reductions in divergence at recombination breakpoints. Although indels occasionally transformed as parts of longer recombination tracts, they were common at breakpoints, suggesting that indels typically block progression of strand exchange. Some colonies had recombination tracts in which variant positions contained mixtures of both donor and recipient alleles. These tracts were clustered around the origin of replication and were interpreted as the result of heteroduplex segregation in the original transformed cell. Finally, a pilot experiment demonstrated the utility of natural transformation for genetically dissecting natural phenotypic variation. We discuss our results in the context of the potential to merge experimental and population genetic approaches, giving a more holistic understanding of bacterial gene transfer. PMID:24569039

  1. Comparative genomics reveals multiple causes of variation in mycotoxin production among Fusarium

    Science.gov (United States)

    Collectively, species of Fusarium produce a structurally diverse array of mycotoxins and other secondary metabolites (SMs), but individual species contribute to only a fraction of this diversity. To elucidate causes of variation in SM production among species, we are examining the distribution and e...

  2. Copy number variation in the genomes of twelve natural isolates of Caenorhabditis elegans

    OpenAIRE

    Flibotte Stephane; Edgley Mark L; Lorch Adam; Maydan Jason S; Moerman Donald G

    2010-01-01

    Abstract Background Copy number variation is an important component of genetic variation in higher eukaryotes. The extent of natural copy number variation in C. elegans is unknown outside of 2 highly divergent wild isolates and the canonical N2 Bristol strain. Results We have used array comparative genomic hybridization (aCGH) to detect copy number variation in the genomes of 12 natural isolates of Caenorhabditis elegans. Deletions relative to the canonical N2 strain are more common in these ...

  3. Natural Genetic Variation Influences Protein Abundances in C. elegans Developmental Signalling Pathways.

    Directory of Open Access Journals (Sweden)

    Kapil Dev Singh

    Full Text Available Complex traits, including common disease-related traits, are affected by many different genes that function in multiple pathways and networks. The apoptosis, MAPK, Notch, and Wnt signalling pathways play important roles in development and disease progression. At the moment we have a poor understanding of how allelic variation affects gene expression in these pathways at the level of translation. Here we report the effect of natural genetic variation on transcript and protein abundance involved in developmental signalling pathways in Caenorhabditis elegans. We used selected reaction monitoring to analyse proteins from the abovementioned four pathways in a set of recombinant inbred lines (RILs generated from the wild-type strains N2 (Bristol and CB4856 (Hawaii to enable quantitative trait locus (QTL mapping. About half of the cases from the 44 genes tested showed a statistically significant change in protein abundance between various strains, most of these were however very weak (below 1.3-fold change. We detected a distant QTL on the left arm of chromosome II that affected protein abundance of the phosphatidylserine receptor protein PSR-1, and two separate QTLs that influenced embryonic and ionizing radiation-induced apoptosis on chromosome IV. Our results demonstrate that natural variation in C. elegans is sufficient to cause significant changes in signalling pathways both at the gene expression (transcript and protein abundance and phenotypic levels.

  4. On the causes and mechanisms of the long-term variations in the GCR characteristics

    CERN Document Server

    Krainev, M; Potgieter, M S

    2015-01-01

    We argue that the degree of understanding the causes and mechanisms of the long-term variations (11-year and 22-year) in the galactic cosmic rays (GCR) characteristics is still insufficient and to improve it we need new approaches and methods. For the time being there is a long-lasting controversy on how these long-term variations, observed for more than 50 years in the inner heliosphere, are formed. It is widely believed that the 11-year variation is due entirely to the toroidal branch of solar activity (the area and number of sunspots, the strength of the heliospheric magnetic field etc) because of the diffusion, convection and adiabatic energy loss, while the much smaller 22-year variation is caused by the particle drifts connected with the poloidal branch of solar activity (the high-latitude solar magnetic fields). At the same time, both past and more recent numerical simulations indicate that the contribution of particle drifts could be significant for both 22- and 11-year variations in the GCR intensiti...

  5. Carbon and hydrogen isotope variations in methane from natural gas and from thermal cracking

    International Nuclear Information System (INIS)

    The isotope ratio of methane from natural gas of the Thuringia Basin follows the relation delta D = 5.7 delta 13C + 23. The delta D values of the methane component of the gas vary from -238 to -80 0/00, referred to SMOW, whereas the corresponding delta 13C values vary from -46.9 to -23.9 0/00, referred to PDB. In order to elucidate carbon and hydrogen isotope fractionations in thermal cracking, model experiments have been carried out. For this purpose methane was produced by cracking hexadecane at 400 0C. The following relation was found: delta D = 7.1 delta 13C - 28. The hitherto existing conceptions of the causes of the extraordinarily great isotope variations observed in natural gases of the Thuringia Basin are discussed on the basis of the new experimental data

  6. 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

  7. radiation exposure at work places caused by natural radionuclides

    International Nuclear Information System (INIS)

    The new Euratom basic standards for radiological protection (guideline 96/29/Euratom of the Council of 13 May 1996 on the Determination of Basic Safety Standards for the protection of Health of Staff and Population against the Dangers by Ionizing radiation) contain in section 2 of the Title VII, which deals with exposure by natural radiation sources, a request to by the EC member states to determine by investigations or other appropriate means the work places which are of importance with regard to natural radiation exposure. Against the background of the implementation of these new Euratom basic standards, a work group named, radiation Exposure at Work Places by Natural Radionuclides was founded in November 1994 by the German Commission on Radiological protection. This working group was supposed to determine the possible exposure pathways by natural radiation, the extent of radiation exposure at work places for these exposure pathways, and the number of employed persons affected by the different exposure pathways and to compile the gained information in a survey. The following report gives a comprehensive survey on the results of these investigations and their relevance to radiological protection. (author)

  8. A joint history of the nature of genetic variation and the nature of schizophrenia.

    Science.gov (United States)

    Kendler, K S

    2015-02-01

    This essay traces the history of concepts of genetic variation and schizophrenia from Darwin and Mendel to the present. For Darwin, the important form of genetic variation for evolution is continuous in nature and small in effect. Biometricians led by Pearson agreed and developed statistical genetic approaches utilizing trait correlations in relatives. Mendel studied discontinuous traits and subsequent Mendelians, led by Bateson, assumed that important genetic variation was large in effect producing discontinuous phenotypes. Although biometricians studied 'insanity', schizophrenia genetics under Kraepelin and Rüdin utilized Mendelian approaches congruent with their anatomical-clinical disease model of dementia praecox. Fisher showed, assuming many genes of small effect, Mendelian and Biometrical models were consilient. Echoing prior conflicts, psychiatric genetics since then has utilized both biometrical models, largely in twins, and Mendelian models, based on advancing molecular techniques. In 1968, Gottesman proposed a polygenic model for schizophrenia based on a threshold version of Fisher's theory. Since then, rigorous studies of the schizophrenia spectrum suggest that genetic risk for schizophrenia is more likely continuous than categorical. The last 5 years has seen increasingly convincing evidence from genome-wide association study (GWAS) and sequencing that genetic risk for schizophrenia is largely polygenic, and congruent with Fisher's and Gottesman's models. The gap between biometrical and molecular Mendelian models for schizophrenia has largely closed. The efforts to ground a categorical biomedical model of schizophrenia in Mendelian genetics have failed. The genetic risk for schizophrenia is widely distributed in human populations so that we all carry some degree of risk. PMID:25134695

  9. Photocentric variability of quasars caused by variations in their inner structure: consequences for Gaia measurements

    Science.gov (United States)

    Popović, L. Č.; Jovanović, P.; Stalevski, M.; Anton, S.; Andrei, A. H.; Kovačević, J.; Baes, M.

    2012-02-01

    Context. We study the photocenter position variability caused by variations in the quasar inner structure. We consider the variability in the accretion disk emissivity and torus structure variability caused by the different illumination by the central source. We discuss the possible detection of these effects by Gaia. Observations of the photocenter variability in two AGNs, SDSS J121855+020002 and SDSS J162011+1724327 have been reported and discussed. Aims: For variations in the quasar inner structure, we explore how much this effect can affect the position determination and whether it can (or not) be detected with the Gaia mission. Methods: We use models of (a) a relativistic disk, including the perturbation that can increase the brightness of part of the disk, and consequently offset the photocenter position, and (b) a dusty torus that absorbs and re-emits the incoming radiation from the accretion disk (central continuum source). We estimate the value of the photocenter offset caused by these two effects. Results: We found that perturbations in the inner structure can cause a significant offset to the photocenter. This offset depends on the characteristics of both the perturbation and accretion disk and on the structure of the torus. In the case of the two considered QSOs, the observed photocenter offsets cannot be explained by variations in the accretion disk and other effects should be considered. We discuss the possibility of exploding stars very close to the AGN source, and also that there are two variable sources at the center of these two AGNs that may indicate a binary supermassive black hole system on a kpc (pc) scale. Conclusions: The Gaia mission seems to be very promising, not only for astrometry, but also for exploring the inner structure of AGNs. We conclude that variations in the quasar inner structure can affect the observed photocenter (by up to several mas). There is a chance to observe such an effect in the case of bright and low-redshift QSOs.

  10. Human alteration of natural light cycles: causes and ecological consequences

    OpenAIRE

    Gaston, Kevin J; Duffy, James P.; Gaston, Sian; Bennie, Jonathan; Davies, Thomas W

    2014-01-01

    Artificial light at night is profoundly altering natural light cycles, particularly as perceived by many organisms, over extensive areas of the globe. This alteration comprises the introduction of light at night at places and times at which it has not previously occurred, and with different spectral signatures. Given the long geological periods for which light cycles have previously been consistent, this constitutes a novel environmental pressure, and one for which there is evidence for biolo...

  11. A transcriptional network associated with natural variation in Drosophila aggressive behavior

    OpenAIRE

    Edwards, Alexis C.; Ayroles, Julien F.; STONE, ERIC A.; Carbone, Mary Anna; Lyman, Richard F.; Mackay, Trudy FC

    2009-01-01

    Background Aggressive behavior is an important component of fitness in most animals. Aggressive behavior is genetically complex, with natural variation attributable to multiple segregating loci with allelic effects that are sensitive to the physical and social environment. However, we know little about the genes and genetic networks affecting natural variation in aggressive behavior. Populations of Drosophila melanogaster harbor quantitative genetic variation in aggressive behavior, providing...

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Variation in predator species abundance can cause variable selection pressure on warning signaling prey.

    Science.gov (United States)

    Valkonen, Janne K; Nokelainen, Ossi; Niskanen, Martti; Kilpimaa, Janne; Björklund, Mats; Mappes, Johanna

    2012-08-01

    Predation pressure is expected to drive visual warning signals to evolve toward conspicuousness. However, coloration of defended species varies tremendously and can at certain instances be considered as more camouflaged rather than conspicuous. Recent theoretical studies suggest that the variation in signal conspicuousness can be caused by variation (within or between species) in predators' willingness to attack defended prey or by the broadness of the predators' signal generalization. If some of the predator species are capable of coping with the secondary defenses of their prey, selection can favor reduced prey signal conspicuousness via reduced detectability or recognition. In this study, we combine data collected during three large-scale field experiments to assess whether variation in avian predator species (red kite, black kite, common buzzard, short-toed eagle, and booted eagle) affects the predation pressure on warningly and non-warningly colored artificial snakes. Predation pressure varied among locations and interestingly, if common buzzards were abundant, there were disadvantages to snakes possessing warning signaling. Our results indicate that predator community can have important consequences on the evolution of warning signals. Predators that ignore the warning signal and defense can be the key for the maintenance of variation in warning signal architecture and maintenance of inconspicuous signaling. PMID:22957197

  14. Variation in predator species abundance can cause variable selection pressure on warning signaling prey

    Science.gov (United States)

    Valkonen, Janne K; Nokelainen, Ossi; Niskanen, Martti; Kilpimaa, Janne; Björklund, Mats; Mappes, Johanna

    2012-01-01

    Predation pressure is expected to drive visual warning signals to evolve toward conspicuousness. However, coloration of defended species varies tremendously and can at certain instances be considered as more camouflaged rather than conspicuous. Recent theoretical studies suggest that the variation in signal conspicuousness can be caused by variation (within or between species) in predators' willingness to attack defended prey or by the broadness of the predators' signal generalization. If some of the predator species are capable of coping with the secondary defenses of their prey, selection can favor reduced prey signal conspicuousness via reduced detectability or recognition. In this study, we combine data collected during three large-scale field experiments to assess whether variation in avian predator species (red kite, black kite, common buzzard, short-toed eagle, and booted eagle) affects the predation pressure on warningly and non-warningly colored artificial snakes. Predation pressure varied among locations and interestingly, if common buzzards were abundant, there were disadvantages to snakes possessing warning signaling. Our results indicate that predator community can have important consequences on the evolution of warning signals. Predators that ignore the warning signal and defense can be the key for the maintenance of variation in warning signal architecture and maintenance of inconspicuous signaling. PMID:22957197

  15. 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. PMID:26830772

  16. On the Cause of Eastern Equatorial Pacific Ocean T-S Variations Associated with El Nino

    Science.gov (United States)

    Wang, Ou; Fukumori, Ichiro; Lee, Tong; Cheng, Benny

    2004-01-01

    The nature of observed variations in temperature-salinity (T-S) relationship between El Nino and non-El Nino years in the pycnocline of the eastern equatorial Pacific Ocean (NINO3 region, 5(deg)S-5(deg)N, 150(deg)W-90(deg)W) is investigated using an ocean general circulation model. The origin of the subject water mass is identified using the adjoint of a simulated passive tracer. The higher salinity during El Nino is attributed to larger convergence of saltier water from the Southern Hemisphere and smaller convergence of fresher water from the Northern Hemisphere.

  17. Untangling individual variation in natural populations: ecological, genetic and epigenetic correlates of long-term inequality in herbivory

    OpenAIRE

    Carlos M Herrera; Bazaga, Pilar

    2011-01-01

    Individual variation in ecologically important features of organisms is a crucial element in ecology and evolution, yet disentangling its underlying causes is difficult in natural populations. We applied a genomic scan approach using amplified fragment length polymorphism (AFLP) markers to quantify the genetic basis of long-term individual differences in herbivory by mammals at a wild population of the violet Viola cazorlensis monitored for two decades. In addition, methylation-...

  18. 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.

  19. Modelling seasonal variations of natural radionuclides in agricultural soils

    OpenAIRE

    Guagliardi I.; Buttafuoco G; Ricca N.; Cipriani M. G.; Civitelli D.; Froio R.; Gabriele A. L.; De, Rosa R.

    2013-01-01

    Estimating activity of natural radionuclides in agricultural soil is very important for the protection of public health because the released radioactivity can enter the food chain. Radioactivity measurements were carried out in two different dates (winter and summer) in agricultural soil using a GRM-260 gamma-ray spectrometer. The study area (100 m x 100 m) was an olive orchard in southern Italy. Measurements were carried out at 361 locations in January and July 2011. At the same locations, s...

  20. Monitoring natural and anthropogenic induced variations in water availability across Africa

    Science.gov (United States)

    Ahmed, M.; Sultan, M.; Wahr, J. M.; Yan, E.

    2014-12-01

    Africa, the second-driest continent in the world after Australia, is one of the most vulnerable continents to climate change. Understanding the impacts of climatic and anthropogenic factors on Africa's hydrologic systems is vital for the assessment and utilization of Africa's water resources. In this study, we utilize the Gravity Recovery and Climate Experiment (GRACE) and land surface models (LSM; GLDAS and CLM4.5) in conjunction with other readily-available temporal climatic and remote sensing, geological and hydrological datasets for monitoring the spatial and temporal trends in Terrestrial Water Storage (TWS) over a time period of 10 years (01/2003-12/2012) over the African continent and to investigate the nature (e.g., climatic and/or human pressures-related) of, and the controlling factors causing, these variations. Spatial and temporal (i.e., time series analysis) correlations of the trends extracted from GRACE-derived (TWSGRACE) and LSM-derived (TWSLSM) TWS indicate the following: (1) Large (≥ 90 % by area) sectors of Africa are undergoing statistically significant TWSGRACE and TWSLSM variations due to natural and anthropogenic causes; (2) a general correspondence between TWSGRACE and TWSLSM over areas (e.g., Niger and Mozambique NE basins in eastern and western Africa) largely controlled by natural (i.e., increase/decrease in precipitation and/or temperature) causes; (3) discrepancies are observed over areas that witnessed extensive anthropogenic effects measured by TWSGRACE but unaccounted for by TWSLSM. Examples include: (a) strong (compared to that observed by TWSLSM) negative TWSGRACE trends were observed over areas that witnessed heavy groundwater extraction (e.g., Western, Desert, Egypt); (b) strong (compared to that observed by TWSLSM) positive TWSGRACE over Lake Volta reservoir; and (c) strong (compared to that observed by TWSLSM) negative trends over areas undergoing heavy deforestation (e.g., northern and NW Congo Basin); (4) additional

  1. Hydrological mass variations caused by extreme weather conditions in Aisa measured by GRACE TVG data

    Science.gov (United States)

    Zhang, Z.; Chao, B. F.

    2012-12-01

    Droughts, excessive rain, snowstorm, and flooding caused by extreme weather conditions, which occurred frequently in China during the last several years, are primarily associated with hydrological mass variations. The dual-satellite mission of GRACE (Gravity Recovery And Climate Experiment) launched in 2002 has enabled measurement of the Earth's (tiny) time-variable gravity (TVG), providing new and precise information about mass transport on or in the Earth, especially short periodic hydrological mass variations. In this study, we examine terrestrial water storage (TWS) changes in Chongqing (great drought occurred in 2006 summer), south China (snowstorm occurred in early 2008) and Thailand (flood occurred in 2011) using GRACE RL05 (RL04) time-variable gravity (TVG) data and predications from major climate and land surface models, including the National Centers for Environmental Prediction (NCEP) and European Centre for Medium-Range Weather Forecasts (ECWMF) reanalysis climate model and the global land data assimilation system (GLDAS) and river gauge data. The results demonstrate the unique potential of GRACE measurements in monitoring large-scale hydrological mass variation events and in evaluating advanced climate and land surface models.

  2. Assessment of the impact caused by natural disasters: simplified procedures and open problems

    OpenAIRE

    Petrucci, Olga; CNR-IRPI

    2012-01-01

    A natural hazard is a geophysical, atmospheric or hydrological event (e.g., earthquake, landslide, tsunami, windstorm, flood or drought) that has the potential to cause harm or loss, while a natural disaster is the occurrence of an extreme hazard event that impacts on communities causing damage, disruption and casualties, and leaving the affected communities unable to function normally without outside assistance (Twig, 2007). The definition of natural disaster impact (NDI) can change accor...

  3. Causes and consequences of spatial variation in sex ratios in a declining bird species.

    Science.gov (United States)

    Morrison, Catriona A; Robinson, Robert A; Clark, Jacquie A; Gill, Jennifer A

    2016-09-01

    Male-biased sex ratios occur in many bird species, particularly in those with small or declining populations, but the causes of these skews and their consequences for local population demography are rarely known. Within-species variation in sex ratios can help to identify the demographic and behavioural processes associated with such biases. Small populations may be more likely to have skewed sex ratios if sex differences in survival, recruitment or dispersal vary with local abundance. Analyses of species with highly variable local abundances can help to identify these mechanisms and the implications for spatial variation in demography. Many migratory bird species are currently undergoing rapid and severe declines in abundance in parts of their breeding ranges and thus have sufficient spatial variation in abundance to explore the extent of sex ratio biases, their causes and implications. Using national-scale bird ringing data for one such species (willow warbler, Phylloscopus trochilus), we show that sex ratios vary greatly across Britain and that male-biased sites are more frequent in areas of low abundance, which are now widespread across much of south and east England. These sex ratio biases are sufficient to impact local productivity, as the relative number of juveniles caught at survey sites declines significantly with increasing sex ratio skew. Sex differences in survival could influence this sex ratio variation, but we find little evidence for sex differences in survival increasing with sex ratio skew. In addition, sex ratios have become male-biased over the last two decades, but there are no such trends in adult survival rates for males or females. This suggests that lower female recruitment into low abundance sites is contributing to these skews. These findings suggest that male-biased sex ratios in small and declining populations can arise through local-scale sex differences in survival and dispersal, with females recruiting disproportionately into larger

  4. Co-Regulated Transcriptional Networks Contribute to Natural Genetic Contribute Variation in Drosophila Sleep

    OpenAIRE

    Harbison, Susan T; Carbone, Mary Anna; Ayroles, Julien F.; Stone, Eric A.; Lyman, Richard F; Mackay, Trudy F C

    2009-01-01

    Sleep disorders are common in humans, and sleep loss increases the risk of obesity and diabetes1. Studies in Drosophila 2, 3 have revealed molecular pathways4–7 and neural tissues8–10 regulating sleep; however, genes that maintain genetic variation for sleep in natural populations are unknown. Here, we characterized sleep in 40 wild-derived Drosophila lines and observed abundant genetic variation in sleep architecture. We associated sleep with genome-wide variation in gene expression11 to ide...

  5. Using natural variation to unravel the dynamic regulation of plant performance in diverse environments

    OpenAIRE

    Molenaar, J.A.

    2015-01-01

    Summary All plants are able to respond to changes in their environment by adjusting their morphology and metabolism, but large differences are observed in the effectiveness of these responses in the light of plant fitness. Between and within species large differences are observed in plant responses to drought, heat and other abiotic stresses. This natural variation is partly due to variation in the genetic composition of individuals. Within-species variation can be used to identify and study ...

  6. 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.

  7. Some observations of the variations in natural gamma radiation due to rainfall

    International Nuclear Information System (INIS)

    Results of observations of variations in natural gamma-radiation flux densities due to rainfall are presented and discussed in relation to rate of rainfall. Variations of fluences with amounts of rainfall are also described. It is concluded that the frequency distribution of the ratio of the fluence to the amount of rainfall has a trend to be lognormal

  8. Analysis of Natural Variation in Bermudagrass (Cynodon dactylon) Reveals Physiological Responses Underlying Drought Tolerance

    OpenAIRE

    Haitao Shi; Yanping Wang; Zhangmin Cheng; Tiantian Ye; Zhulong Chan

    2012-01-01

    Bermudagrass (Cynodon dactylon) is a widely used warm-season turfgrass and one of the most drought tolerant species. Dissecting the natural variation in drought tolerance and physiological responses will bring us powerful basis and novel insight for plant breeding. In the present study, we evaluated the natural variation of drought tolerance among nine bermudagrass varieties by measuring physiological responses after drought stress treatment through withholding water. Three groups differing i...

  9. Nature Based Tourism, Seasonal Variation and its Impact on Employment and Income: Evidence from Meghalaya

    OpenAIRE

    Utpal KUMAR DE; Amrita DEVI

    2010-01-01

    The present paper attempts to examine the impact of nature based tourism in Meghalaya on the income and employment. Nature based tourism has important impact on the welfare of the local people of Meghalaya, especially women who have been engaged in various tourism related activities along with the others involved in hotel and higher level activities related to tourism. It is examined through the variation in income and employment in relation to the seasonal variation in tourist inflow in vari...

  10. 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...

  11. 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.

  12. Unused Natural Variation Can Lift Yield Barriers in Plant Breeding

    Directory of Open Access Journals (Sweden)

    Gur Amit

    2004-01-01

    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.

  13. Precipitation over two Southern Hemisphere locations: Long-term variation linked to natural and anthropogenic forcings

    Science.gov (United States)

    Heredia, Teresita; Elias, Ana G.

    2016-03-01

    The precipitation over Tucuman (26.8°S, 65.2°W), Argentina, and Sidney (33.8°S, 151.2°E), Australia, present similar long-term variation patterns. In this work anthropogenic and solar forcings are analyzed as possible drivers of this behavior. Due to the nature of the processes that lead to precipitation, the discernment between solar and anthropogenic effects, and the link between precipitation and solar activity are highly complex and hard to detect. The aim of this work is to convey the importance of recognizing and quantifying the different forcing acting on precipitation which sometimes are not exposed by a statistical analysis. Annual mean precipitation time series together with solar and geomagnetic activity indices and atmospheric CO2 are analyzed. In order to survey the role of different forcing on precipitation variation we used wavelet and regression analysis with CO2, Rz and aa as independent variables acting as anthropogenic, solar and geomagnetic activity forcing respectively. In the long-term, all of them, considered separately, would induce a similar mean increase in precipitation. The increasing concentration of greenhouse gases, which is thought to be the main factor causing the global warming, is expected to induce an increasing trend of ∼0.8 mm/year, according to some authors. In our case, we obtain a much smaller value: ∼0.15 mm/year which in addition, is similar to the expected forcing from Rz or aa. The wavelet analysis yield significant results for the quasi-decadal and longer-term variations only in the case of Sydney. Significant correlations at time-scales longer than 22 years are also obtained through the regression analysis for Sydney. Although Tucuman do not present significant results, there is a clear similar behavior in the long-term trend. In spite of the fact that the present analysis do not allow us to determine the "true" forcing of the overall increasing trend observed in precipitation, it points out not only

  14. 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.

  15. Genetic diversity in cytokines associated with immune variation and resistance to multiple pathogens in a natural rodent population.

    Directory of Open Access Journals (Sweden)

    Andrew K Turner

    2011-10-01

    Full Text Available Pathogens are believed to drive genetic diversity at host loci involved in immunity to infectious disease. To date, studies exploring the genetic basis of pathogen resistance in the wild have focussed almost exclusively on genes of the Major Histocompatibility Complex (MHC; the role of genetic variation elsewhere in the genome as a basis for variation in pathogen resistance has rarely been explored in natural populations. Cytokines are signalling molecules with a role in many immunological and physiological processes. Here we use a natural population of field voles (Microtus agrestis to examine how genetic diversity at a suite of cytokine and other immune loci impacts the immune response phenotype and resistance to several endemic pathogen species. By using linear models to first control for a range of non-genetic factors, we demonstrate strong effects of genetic variation at cytokine loci both on host immunological parameters and on resistance to multiple pathogens. These effects were primarily localized to three cytokine genes (Interleukin 1 beta (Il1b, Il2, and Il12b, rather than to other cytokines tested, or to membrane-bound, non-cytokine immune loci. The observed genetic effects were as great as for other intrinsic factors such as sex and body weight. Our results demonstrate that genetic diversity at cytokine loci is a novel and important source of individual variation in immune function and pathogen resistance in natural populations. The products of these loci are therefore likely to affect interactions between pathogens and help determine survival and reproductive success in natural populations. Our study also highlights the utility of wild rodents as a model of ecological immunology, to better understand the causes and consequences of variation in immune function in natural populations including humans.

  16. Natural variation for lifespan and stress response in the nematode Caenorhabditis remanei.

    Science.gov (United States)

    Reynolds, Rose M; Phillips, Patrick C

    2013-01-01

    Genetic approaches (e.g. mutation, RNA interference) in model organisms, particularly the nematode Caenorhabditis elegans, have yielded a wealth of information on cellular processes that can influence lifespan. Although longevity mutants discovered in the lab are instructive of cellular physiology, lab studies might miss important genes that influence health and longevity in the wild. C. elegans has relatively low natural genetic variation and high levels of linkage disequilibrium, and thus is not optimal for studying natural variation in longevity. In contrast, its close relative C. remanei possesses very high levels of molecular genetic variation and low levels of linkage disequilibrium. To determine whether C. remanei may be a good model system for the study of natural genetic variation in aging, we evaluated levels of quantitative genetic variation for longevity and resistance to oxidative, heat and UV stress. Heritability (and the coefficient of additive genetic variation) was high for oxidative and heat stress resistance, low (but significant) for longevity, and essentially zero for UV stress response. Our results suggest that C. remanei may be a powerful system for studying natural genetic variation for longevity and oxidative and heat stress response, as well as an informative model for the study of functional relationships between longevity and stress response. PMID:23658604

  17. Does infectious disease cause global variation in the frequency of intrastate armed conflict and civil war?

    Science.gov (United States)

    Letendre, Kenneth; Fincher, Corey L; Thornhill, Randy

    2010-08-01

    Geographic and cross-national variation in the frequency of intrastate armed conflict and civil war is a subject of great interest. Previous theory on this variation has focused on the influence on human behaviour of climate, resource competition, national wealth, and cultural characteristics. We present the parasite-stress model of intrastate conflict, which unites previous work on the correlates of intrastate conflict by linking frequency of the outbreak of such conflict, including civil war, to the intensity of infectious disease across countries of the world. High intensity of infectious disease leads to the emergence of xenophobic and ethnocentric cultural norms. These cultures suffer greater poverty and deprivation due to the morbidity and mortality caused by disease, and as a result of decreased investment in public health and welfare. Resource competition among xenophobic and ethnocentric groups within a nation leads to increased frequency of civil war. We present support for the parasite-stress model with regression analyses. We find support for a direct effect of infectious disease on intrastate armed conflict, and support for an indirect effect of infectious disease on the incidence of civil war via its negative effect on national wealth. We consider the entanglements of feedback of conflict into further reduced wealth and increased incidence of disease, and discuss implications for international warfare and global patterns of wealth and imperialism. PMID:20377573

  18. An analytical model for Doppler frequency variations of ionospheric HF sounding caused by SSC

    Science.gov (United States)

    Pilipenko, V.; Fedorov, E.; Yumoto, K.; Ikeda, A.; Sun, T. R.

    2010-10-01

    A theoretical model to interpret the deviations of the Doppler sounding radio frequency during the SSC is proposed. The Doppler response is composed from long-period deviation with time scale ˜10 min and short-lived (˜1 min) positive spike. For the interpretation of this spike, the variations of Doppler velocity induced by compressional and Alfvén waves are theoretically estimated on the basis of the thin ionosphere approximation. The analytical model developed goes beyond the older numerical model which has been in use thus far to explain certain facets of the correlation between geomagnetic variations and HF Doppler shifts. This new model provides the possibility to easily estimate the Doppler frequency response to either Alfvén or compresssional modes for extraordinary and ordinary radio waves. A theoretical estimate indicates that, for the same amplitude of the ground magnetic disturbances, a large-scale compressional mode produces a larger ionospheric response than an Alfvén mode. The plasma vertical displacement caused by the ULF inductive electric field is shown to be the dominating effect. The magnitudes and waveforms of the simultaneously detected ionospheric and magnetic responses on SSC at a low-latitude site in Japan fit the considered model.

  19. Nongenetic causes of childhood cancers: evidence from international variation, time trends, and risk factor studies

    International Nuclear Information System (INIS)

    Ionizing radiation and a variety of genetic conditions are thought to explain 5-10% of childhood cancers. Infection with Epstein-Barr virus (EBV) in parts of Africa and human immunodeficiency virus (HIV) increase the risk of Burkitt's lymphoma and Kaposi's sarcoma, respectively. Other risk factors have not been conclusively identified. A review of the data on international variation in incidence, recent changes in incidence, and risk factors suggests that many childhood cancers are likely to have nongenetic causes. The pattern of international variation and associations with surrogates of infection suggest an infectious etiology for acute lymphoblastic leukemia, although no agent has been identified. The biologic plausibility is strong that maternal consumption of food containing DNA topoisomerase II inhibitors may increase the risk of acute myeloid leukemia, although the data are limited now. For brain tumors, cured meats, polyomaviruses, and farm exposures may have etiologic roles. Changes in the incidence and characteristics of children with hepatoblastoma as well as risk factor studies suggest a role for an exposure of very low birth weight babies. High birth weight, tea or coffee consumption, and certain paternal occupations have shown some consistency in their association with Wilms' tumor. For most of the other cancers, very few epidemiologic studies have been conducted, so it is not surprising that nongenetic risk factors have not been detected. The most important difference between the cancers for which there are good etiologic clues and those for which there are not may be the number of relevant studies

  20. 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

  1. 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.

  2. Variation of weather radar sensitivity at ground level and from space: case studies and possible causes

    Energy Technology Data Exchange (ETDEWEB)

    Joss, J. [Motto, Intragna (Switzerland); Gabella, M.; Perona, G. [Politecnico di Torino - Electronics Dept., Torino (Italy); Michaelides, S.C. [Meteorological Service, Nicosia (Cyprus)

    2006-10-15

    Firstly, this paper summarizes the procedure for correcting the variation of sensitivity of radars at ground level, using a radar in space for reference, as already described in the literature. Around 10dB have to be added to the measured radar reflectivity Z (in mm{sup 6}/m{sup 3}), when increasing the range from 10 km to 100 km. In other words, instead of an r{sup -2}-dependence (where r is the range, i.e. the distance between the radar and the meteorological target), we find an apparent reduction proportional to r{sup -3}. A similar procedure is used to analyze the dependence of the TRMM radar, using the adjusted data of the radar at ground level for reference. We have to add around 3dB to the measured reflectivity, when increasing the distance from close to Nadir (10 km) to the edge of the swath (100 km). In other words, instead of a constant sensitivity over the swath of the satellite, we find a reduction of sensitivity with the range, proportional to r{sup -0.3}. Secondly, the paper illustrates possible causes of the systematic range dependence of both radars. The old, dominant cause - overshooting of precipitation - is already vastly discussed in literature. We describe the variability of the precipitation with three case studies. The variability of the precipitation is difficult to quantify. It is concluded to be responsible for the variable range dependence and for many disillusions with radar. (orig.)

  3. 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.

  4. Natural Genetic Variation and Candidate Genes for Morphological Traits in Drosophila melanogaster.

    Science.gov (United States)

    Carreira, Valeria Paula; Mensch, Julián; Hasson, Esteban; Fanara, Juan José

    2016-01-01

    Body size is a complex character associated to several fitness related traits that vary within and between species as a consequence of environmental and genetic factors. Latitudinal and altitudinal clines for different morphological traits have been described in several species of Drosophila and previous work identified genomic regions associated with such variation in D. melanogaster. However, the genetic factors that orchestrate morphological variation have been barely studied. Here, our main objective was to investigate genetic variation for different morphological traits associated to the second chromosome in natural populations of D. melanogaster along latitudinal and altitudinal gradients in Argentina. Our results revealed weak clinal signals and a strong population effect on morphological variation. Moreover, most pairwise comparisons between populations were significant. Our study also showed important within-population genetic variation, which must be associated to the second chromosome, as the lines are otherwise genetically identical. Next, we examined the contribution of different candidate genes to natural variation for these traits. We performed quantitative complementation tests using a battery of lines bearing mutated alleles at candidate genes located in the second chromosome and six second chromosome substitution lines derived from natural populations which exhibited divergent phenotypes. Results of complementation tests revealed that natural variation at all candidate genes studied, invected, Fasciclin 3, toucan, Reticulon-like1, jing and CG14478, affects the studied characters, suggesting that they are Quantitative Trait Genes for morphological traits. Finally, the phenotypic patterns observed suggest that different alleles of each gene might contribute to natural variation for morphological traits. However, non-additive effects cannot be ruled out, as wild-derived strains differ at myriads of second chromosome loci that may interact

  5. Pressure Fluctuations in Natural Gas Networks caused by Gas-Electric Coupling

    OpenAIRE

    Chertkov, Misha; Fisher, Michael; Backhaus, Scott; Bent, Russell; Misra, Sidhant

    2015-01-01

    The development of hydraulic fracturing technology has dramatically increased the supply and lowered the cost of natural gas in the United States, driving an expansion of natural gas-fired generation capacity in several electrical inter-connections. Gas-fired generators have the capability to ramp quickly and are often utilized by grid operators to balance intermittency caused by wind generation. The time-varying output of these generators results in time-varying natural gas consumption rates...

  6. Quasispecies variation of porcine reproductive and respiratory syndrome virus during natural infection

    International Nuclear Information System (INIS)

    Porcine reproductive and respiratory syndrome virus (PRRSV) displays notorious genetic, antigenic, and clinical variability. Little is known, however, about the nature and extent of viral variation present within naturally infected animals. By amplifying and cloning the open reading frame 5 gene from tonsils of naturally infected swine, and by sequencing individual clones, we characterized viral diversity in nine animals from two farms. All animals harbored multiple PRRSV variants at both the nucleic and the amino acid levels. Structural variation and rates of synonymous and nonsynonymous nucleotide substitution were no different within known epitopes than elsewhere. Analysis of molecular variance indicated that differences between farms, among animals within farms, and within individual animals accounted for 92.94, 3.84, and 3.22% of the total viral genetic variability observed, respectively. PRRSV exists during natural infection as a quasispecies distribution of related genotypes. Positive natural selection for immune evasiveness does not appear to maintain this diversity

  7. Natural Selection Affects Multiple Aspects of Genetic Variation at Putatively Neutral Sites across the Human Genome

    OpenAIRE

    Lohmueller, Kirk E.; Albrechtsen, Anders; Li, Yingrui; Kim, Su Yeon; Korneliussen, Thorfinn Sand; Vinckenbosch, Nicolas; Tian, Geng; Huerta-Sanchez, Emilia; Feder, Alison F.; Grarup, Niels; Jørgensen, Torben; Jiang, Tao; Witte, Daniel R.; Sandbæk, Annelli; Hellmann, Ines

    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 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 ...

  8. A variational justification of the assumed natural strain formulation of finite elements

    Science.gov (United States)

    Militello, Carmelo; Felippa, Carlos A.

    1991-01-01

    The objective is to study the assumed natural strain (ANS) formulation of finite elements from a variational standpoint. The study is based on two hybrid extensions of the Reissner-type functional that uses strains and displacements as independent fields. One of the forms is a genuine variational principle that contains an independent boundary traction field, whereas the other one represents a restricted variational principle. Two procedures for element level elimination of the strain field are discussed, and one of them is shown to be equivalent to the inclusion of incompatible displacement modes. Also, the 4-node C(exp 0) plate bending quadrilateral element is used to illustrate applications of this theory.

  9. Variation of natural oil and gas reservoir properties at the development process

    International Nuclear Information System (INIS)

    Full text: We know that in some cases the processes of oil and gas development is followed by variations in bardic drive and fluid saturation in the formation, and thus, variations in reservoir-rock properties may take place. The present paper deals with some effects that appear in reservoirs at the development process. Being at natural occurrence conditions the reservoir rocks are influenced by effective pressure. The above pressure is a difference of overburden and formation pressures. The variation of formation pressure results in effective pressure increase, and this, in its turn may result in deformation processes in the formation

  10. Peculiarities of electric and magnetic tipper variations caused by meteorological disturbances in the atmosphere

    Science.gov (United States)

    Adushkin, V. V.; Spivak, A. A.

    2016-01-01

    We present the results of the analysis of experimental data of synchronous observations of variations in the electric and magnetic fields as well as acoustic oscillations in the surface zone of the Earth compared with variations in the meteorological parameters. We demonstrate the synchronous variations in these fields and atmospheric parameters. We revealed, for the first time, not only synchronous but also advancing manifestations of the geomagnetic field perturbations. We introduce a new parameter: the inverse magnetic tipper whose variations during atmospheric perturbations are clearly manifested compared with the variations in the magnetic tipper.

  11. 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

    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...... likely to die at any age, and also prematurely, from natural causes. The consistency of elevated risk across psychiatric diagnoses and causes of death indicates an important health inequality. Those involved in planning and providing mental health services should address the heightened need for physical...

  12. Influence of natural pozzolana and lime additives on the temporal variation of soil compaction and shear strength

    Institute of Scientific and Technical Information of China (English)

    Khelifa HARICHANE; Mohamed GHRICI; Hanifi MISSOUM

    2011-01-01

    Soil stabilization has been practiced for quite some time by adding mixtures,such as cement,lime and fly ash.The additives of lime (L),natural pozzolana (NP) or a combination of both were investigated here on the impact on the temporal variation of geotechnieal characteristics of two cohesive soils.Lime and natural pozzolana were added at the content of 0-8% and 0-20%,respectively.The soil specimens were cured for 1,7,28 and 90 days and then tested for shear strength.Our data show that a combination of lime with natural pozzolana causes the increase in the maximum dry density but the decrease in the optimum moisture content in the gray soil,and vice verse in the red soil.The shear stress of both cohesive soils stabilized with lime or with the combination of lime and natural pozzolana was found to increase with time.The cohesion and the internal friction angle in lime added samples were demonstrated to increase with time.The combination of lime with natural pozzolana exhibits a significant effect on the enhancement of the cohesion and the internal friction angle at later stages.The lime-natural pozzolana combination appears to produce higher shear parameters than lime or natural pozzolana used alone.

  13. Natural Variation in Petal Color in Lycoris longituba Revealed by Anthocyanin Components

    OpenAIRE

    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 ...

  14. 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

  15. Dose variations caused by setup errors in intracranial stereotactic radiotherapy: a PRESAGE study.

    Science.gov (United States)

    Teng, Kieyin; Gagliardi, Frank; Alqathami, Mamdooh; Ackerly, Trevor; Geso, Moshi

    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 1.5mm and 1°, respectively, generated a passing ratio of 62.2%. Translation shift of 0.7mm 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 0.7mm and 0.5° alter the dose distribution. The geometrical displacements affect dose delivery to

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

    International Nuclear Information System (INIS)

    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

  17. Natural variation in morphology of larval amphibians: Phenotypic plasticity in nature?

    OpenAIRE

    Van Buskirk, J

    2009-01-01

    Phenotypic plasticity has been studied intensively in experimental settings but infrequently in nature, and therefore the relevance of experimental findings is poorly known. This is especially true for morphological plasticity in amphibian larvae induced by predators and competitors. This paper describes a seven-year survey of head and tail shape in eight species of anuran and newt larvae in northern Switzerland, involving 6824 individual larvae and 59 ponds. I tested relationships betw...

  18. Natural variation of rice blast resistance gene Pi-d2

    Science.gov (United States)

    Studying natural variation of rice resistance (R) genes in cultivated and wild rice relatives can predict resistance stability to rice blast fungus. In the present study, the protein coding regions of rice R gene Pi-d2 in 35 rice accessions of subgroups, aus (AUS), indica (IND), temperate japonica (...

  19. The atomic weight and isotopic composition of boron and their variation in nature

    International Nuclear Information System (INIS)

    The boron isotopic composition and atomic weight value and their variation in nature are reviewed. Questions are raised about the previously recommended value and the uncertainty for the atomic weight. The problem of what constitutes an acceptable range for normal material and what should then be considered geologically exceptional is discussed. Recent measurements make some previous decisions in need of re-evaluation

  20. 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.

  1. Young Children's Ideas about the Nature, Causes, Justification, and Alleviation of Poverty

    Science.gov (United States)

    Chafel, Judith A.; Neitzel, Carin

    2005-01-01

    Sixty-four 8-year-old boys and girls from urban and rural settings and representing different races and socioeconomic status backgrounds responded to questions about the nature, causes, justification, and alleviation of poverty. Much of what the children said indicated that they had not yet internalized prevailing adult norms and values about the…

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    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 pollu...

  3. Natural selection affects multiple aspects of genetic variation at putatively neutral 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 of...... 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...... 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...

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

    Science.gov (United States)

    Wilschut, Rutger A; Oplaat, Carla; Snoek, L Basten; Kirschner, Jan; Verhoeven, Koen J F

    2016-04-01

    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 have shown the potential for epigenetic mechanisms to contribute to adaptive phenotypes, it remains unknown whether heritable variation in ecologically relevant traits is at least partially epigenetically determined in natural populations. Here, we tested the hypothesis that DNA methylation variation contributes to heritable differences in flowering time within a single widespread apomictic clonal lineage of the common dandelion (Taraxacum officinale s. lat.). Apomictic clone members of the same apomictic lineage collected from different field sites showed heritable differences in flowering time, which was correlated with inherited differences in methylation-sensitive AFLP marker profiles. Differences in flowering between apomictic clone members were significantly reduced after in vivo demethylation using the DNA methyltransferase inhibitor zebularine. This synchronization of flowering times suggests that flowering time divergence within an apomictic lineage was mediated by differences in DNA methylation. While the underlying basis of the methylation polymorphism at functional flowering time-affecting loci remains to be demonstrated, our study shows that epigenetic variation contributes to heritable phenotypic divergence in ecologically relevant traits in natural plant populations. This result also suggests that epigenetic mechanisms can facilitate adaptive divergence within genetically uniform asexual lineages. PMID:26615058

  5. Metabolite profiling and quantitative genetics of natural variation for flavonoids in Arabidopsis

    OpenAIRE

    Routaboul, Jean-Marc; Dubos, Christian; Beck, Gilles; Marques, Catherine; Bidzinski, Przemyslaw; Loudet, Olivier; Lepiniec, Loic

    2012-01-01

    Little is known about the range and the genetic bases of naturally occurring variation for flavonoids. Using Arabidopsis thaliana seed as a model, the flavonoid content of 41 accessions and two recombinant inbred line (RIL) sets derived from divergent accessions (Cvi-0×Col-0 and Bay-0×Shahdara) were analysed. These accessions and RILs showed mainly quantitative rather than qualitative changes. To dissect the genetic architecture underlying these differences, a quantitative trait locus (QTL) a...

  6. Natural Variation for Lifespan and Stress Response in the Nematode Caenorhabditis remanei

    OpenAIRE

    Reynolds, Rose M.; Phillips, Patrick C.

    2013-01-01

    Genetic approaches (e.g. mutation, RNA interference) in model organisms, particularly the nematode Caenorhabditis elegans, have yielded a wealth of information on cellular processes that can influence lifespan. Although longevity mutants discovered in the lab are instructive of cellular physiology, lab studies might miss important genes that influence health and longevity in the wild. C. elegans has relatively low natural genetic variation and high levels of linkage disequilibrium, and thus i...

  7. Genetic Variation for Sex Ratio Traits within a Natural Population of a Parasitic Wasp, Nasonia Vitripennis

    OpenAIRE

    Orzack, S.; Parker, E.D.

    1990-01-01

    By analyzing isofemale strains extracted from a natural population of Nasonia vitripennis, we detected variation for the sex ratios produced in fresh hosts (first sex ratios) and in previously parasitized hosts (second sex ratios). Under simple assumptions of population structure, this between-strain heterogeneity of first sex ratios results in heterogeneity of fitnesses. There is approximately ten percent difference in average fitnesses between the strains. (The fitnesses of second sex ratio...

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

    OpenAIRE

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

    2011-01-01

    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 ...

  9. Crosstalk in a KID Array Caused by the Thickness Variation of Superconducting Metal

    Science.gov (United States)

    Adane, A.; Boucher, C.; Coiffard, G.; Leclercq, S.; Schuster, K. F.; Goupy, J.; Calvo, M.; Hoarau, C.; Monfardini, A.

    2016-07-01

    The work presented in this paper is focused on the improvement of the kinetic detectors used on NIKA2 instrument (New IRAM KID array 2). Based on the simulation and low temperature measurements, it aims at showing how the variations of the superconducting metal corrupt the frequency comb of the kinetic Inductance detectors (KID) in the frequency range (between 1 and 3 GHz), i.e., how the superconducting metal inhomogeneity induces the resonance-to-resonance cross-coupling which deteriorates the homogeneity of the resonance quality factor and the frequency resonance separation. Solutions are then proposed to fight against the effect of these metallic variations when designing the KID array.

  10. Diurnal variation in situ of photosynthetic capacity in ulva is caused by a dark reaction.

    Science.gov (United States)

    Mishkind, M; Mauzerall, D; Beale, S I

    1979-11-01

    Ulva lactuca (sea lettuce) undergoes large diurnal oscillations of light-saturated photosynthetic O(2) evolution in situ. Freshly collected samples from Great Harbor, Woods Hole, Massachusetts, had a maximum white light-saturated rate at noon that was 2.5-fold higher than the rate of matched samples collected at midnight. When kept under constant low level illumination, the cycle persisted for at least 36 hours, and after 2 weeks damped out to a constant level that was halfway between the minimum and maximum rates. The cyclic oscillations were apparent whether expressed on a weight or chlorophyll content basis, occurred in both lightly and heavily pigmented samples, and were not attributable to changes in chloroplast shading due to variations in chloroplast orientation within the frond cells. There were no cyclic variations in the initial slopes of the light saturation curves, in photosynthetic unit size, or in relative quantum efficiency. Measurement of the "fast" turnover time of photosynthesis by the delayed dual flash technique revealed no diurnal variations of this parameter. These results indicate that the cyclic variations in photosynthetic activity are modulated by a dark reaction at a step occurring after reduction of plastoquinone by electrons from photosystem II. PMID:16661078

  11. The nature, causes and effects of school violence in South African high schools

    OpenAIRE

    Vusumzi Nelson Ncontsa; Almon Shumba

    2013-01-01

    We sought to investigate the nature, causes and effects of school violence in four South African high schools. A purposive sample of five principals, 80 learners and 20 educators was selected from the four schools used in the study. A sequential mixed method approach was used in this study; both questionnaires and interviews were used. The design is divided into two phases, beginning with the collection and analysis of quantitative data, followed by the collection and analysis of qualitative ...

  12. Nature and Causes of Learning Difficulties in Genetics at High School Level in Zambia

    OpenAIRE

    Haambokoma, Christopher

    2007-01-01

    Genetics has been identified as one of the difficult topics in biology for high school students in Zambia. This paper reports a study conducted to determine the nature and causes of learning difficulties students encounter in genetics at high school level in Zambia. A survey design was used and data were obtained from students and teachers using interview schedules and self-completion questionnaires. Quota sampling procedure was used to select the sample from the target population. Data colle...

  13. CAUSES AND EFFECTS OF NATURAL ENVIRONMENT DEGRADATION IN THE HYDROGRAPHIC BASIN OF RIVER NEAJLOV

    OpenAIRE

    Luminita Doinea; Tatiana Diaconu; Florin Maracineanu

    2010-01-01

    The paper deals with acute problems of pollution sources and the pressures that these put on the natural environment ina traditionally degraded area due to the development of polluting industries and agricultural activities that operate withoverused and outdated equipment.The case study presents an overview of the hydrographic river basin Neajlov by describing its characteristics and anassessment of the consequences caused by intensive development of agriculture and the industry of oil extrac...

  14. Natural and anthropogenic causes and effects of floods and other disastrous events in Poland

    OpenAIRE

    Dębicki R.

    1998-01-01

    Analysis of natural and anthropogenic causes and effects of floods in Poland is presented in this paper. In general, the flood of 1997 showed that Poland needs, above all, long-term concept for the land development in the basins of the Oder and Vistula, effective legal regulations and development of the hydrotechnical infrastructure. The disastrous flood 1997 made it clear that social and economic losses would have been much smaller if Poland had had a modern measuring, preventing and warning...

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

    International Nuclear Information System (INIS)

    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

  16. 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.

  17. Entrepreneurial Regions: Causes and Consequences of the Spatial Variation of Entrepreneurship

    OpenAIRE

    Modrego Benito, Felix Antonio

    2016-01-01

    The main objective of this thesis is to contribute to the understanding of the spatial variation in entrepreneurship, and its relationship with regional growth and development. The study is conducted using Chile as the empirical setting. The results indicate that conditions for general entrepreneurship, such as access to credit and business dynamism, are not concentrated in the core areas, either nationally or within regions. By contrast, framework conditions enabling innovation and more prod...

  18. 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 ...

  19. 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. PMID:25488978

  20. 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.

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

    OpenAIRE

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

    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 i...

  2. Assessment of Forest Damage in Croatia Caused by Natural Hazards in 2014

    Directory of Open Access Journals (Sweden)

    Dijana Vuletić

    2014-06-01

    Full Text Available Background and Purpose: Recent natural disasters (ice-breaks, torrents, floods that affected five Croatian counties caused significant damage on forest stands and forest infrastructure. Since in Croatia there is no common methodology for fast and reliable assessment of forest damage, the aim of this paper is to develop and present methodology for rapid damage assessment and to prescribe urgent recovery measures, as well as to provide first preliminary results of the total damage to forests. Materials and Methods: An attempt was made to develop the methodology which would rely on existing legislations, regulations, instructions and experiences for forest damage assessment as much as possible. Estimation of forest damage was based on field observations, spatial data of forest management units and data from the existing Forest management plans. Results: According to conducted assessment, forests of Primorsko-goranska County are the most affected by the overall damage caused by ice-storm. Major damages occurred both on the forest and on forest roads. Ice-storm also caused serious damages on forests and on forest roads in Ličko-senjska County and Karlovačka County, while floods and torrents caused damages on forest roads in Zagrebačka County, Sisačko-moslavačka County and Karlovačka County. Money-wise, the total forest damage amounts 942 252 183 €. Conclusions: Methodology for rapid damage assessment presented in this paper resulted on first preliminary estimate of range, intensity and cost of forest damage caused by recent natural disturbances. More precise data on forest damage will be known after the implementation of the proposed emergency recovery measures. Also, certain improvements of methodology in terms of precision and collection of data may be achieved by incorporating remote sensing methods.

  3. 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.

  4. Implications for risk assessment of host factors causing large pharmacokinetic variations

    Energy Technology Data Exchange (ETDEWEB)

    Vesell, E.S.

    1985-12-01

    Normal human subjects vary widely in their capacity to eliminate many drugs and environmental chemicals. These variations range in magnitude from fourfold to fortyfold depending on the drug and the population studied. Pharmacogenetics deals with only one of many host factors responsible for these large pharmacokinetic differences. Age, sex, diet and exposure to other drugs and chemicals, including oral contraceptives, ethanol and cigarette smoking, can alter the genetically determined rate at which a particular subject eliminates drugs and environmental chemicals. These elimination rates, therefore, are dynamic and change even in the same subject with time and condition. Regulatory legislation has only recently begun to recognize this very broad spectrum of human susceptibility and the existence of multiple special subgroups of particularly sensitive subjects. In setting standards for environmental chemicals, EPA and NIOSH have attempted to protect the most sensitive humans and should be encouraged to continue this policy. For some drugs and environmental chemicals, the commonly used safety factor of 100 may be too low; for these chemicals large, interindividual pharmacokinetic variations produced by pharmacogenetic and other host factors may make a safety factor of 400 or 500 more adequate.

  5. Variations of annual and seasonal runoff in Guangdong Province, south China: spatiotemporal patterns and possible causes

    Science.gov (United States)

    Zhang, Qiang; Xiao, Mingzhong; Singh, Vijay P.; Xu, Chong-Yu; Li, Jianfeng

    2015-06-01

    In this study, we thoroughly analyzed spatial and temporal distributions of runoff and their relation with precipitation changes based on monthly runoff dataset at 25 hydrological stations and monthly precipitation at 127 stations in Guangdong Province, south China. Trends of the runoff and precipitation are detected using Mann-Kendall trend test technique. Correlations between runoff and precipitation are tested using Spearman's and Pearson's correlation coefficients. The results indicate that: (1) annual maximum monthly runoff is mainly in decreasing tendency and significant increasing annual minimum monthly runoff is observed in the northern and eastern Guangdong Province. In addition, annual mean runoff is observed to be increasing at the stations located in the West and North Rivers and the coastal region; (2) analysis of seasonal runoff variations indicates increasing runoff in spring, autumn and winter. Wherein, significant increase of runoff is found at 8 stations and only 3 stations are dominated by decreasing runoff in winter; (3) runoff changes of the Guangdong Province are mainly the results of precipitation changes. The Guangdong Province is wetter in winter, spring and autumn. Summer is coming to be drier as reflected by decreasing runoff in the season; (4) both precipitation change and water reservoirs also play important roles in the increasing of annual minimum monthly streamflow. Seasonal shifts of runoff variations may pose new challenges for the water resources management under the influences of climate changes and intensifying human activities.

  6. Unit-based incident reporting and root cause analysis: variation at three hospital unit types

    Science.gov (United States)

    Wagner, Cordula; Merten, Hanneke; Zwaan, Laura; Lubberding, Sanne; Timmermans, Danielle; Smits, Marleen

    2016-01-01

    Objectives To minimise adverse events in healthcare, various large-scale incident reporting and learning systems have been developed worldwide. Nevertheless, learning from patient safety incidents is going slowly. Local, unit-based reporting systems can help to get faster and more detailed insight into unit-specific safety issues. The aim of our study was to gain insight into types and causes of patient safety incidents in hospital units and to explore differences between unit types. Design Prospective observational study. Setting 10 emergency medicine units, 10 internal medicine units and 10 general surgery units in 20 hospitals in the Netherlands participated. Patient safety incidents were reported by healthcare providers. Reports were analysed with root cause analysis. The results were compared between the 3 unit types. Results A total of 2028 incidents were reported in an average reporting period of 8 weeks per unit. More than half had some consequences for patients, such as a prolonged hospital stay or longer waiting time, and a small number resulted in patient harm. Significant differences in incident types and causes were found between unit types. Emergency units reported more incidents related to collaboration, whereas surgical and internal medicine units reported more incidents related to medication use. The distribution of root causes of surgical and emergency medicine units showed more mutual similarities than those of internal medicine units. Conclusions Comparable incidents and causes have been found in all units, but there were also differences between units and unit types. Unit-based incident reporting gives specific information and therefore makes improvements easier. We conclude that unit-based incident reporting has an added value besides hospital-wide or national reporting systems that already exist in various countries. PMID:27329443

  7. Modelling natural grass production and its spatio-temporal variations in a semiarid Mediterranean watershed

    Science.gov (United States)

    Schnabel, Susanne; Lozano-Parra, Javier; Maneta-López, Marco

    2014-05-01

    Natural grasses are found in semiarid rangelands with disperse tree cover of part of the Iberian Peninsula and constitute a resource with high ecologic and economic value worth, being an important source of food for livestock, playing a significant role in the hydrologic cycle, controlling the soil thermal regime, and are a key factor in reducing soil erosion and degradation. However, increasing pressure on the resources, changes in land use as well as possible climate variations threaten the sustainability of natural grasses. Despite of their importance, the spatio-temporal variations of pasture production over whole watersheds are poorly known. In this sense, previous studies by other authors have indicated its dependence on a balance of positive and negative effects brought about by the main limiting factors: water, light, nutrients and space. Nevertheless, the specific weight of each factor is not clear because they are highly variable due to climate characteristics and the structure of these agroforestry systems. We have used a physical spatially-distributed ecohydrologic model to investigate the specific weight of factors that contribute to pasture production in a semiarid watershed of 99.5 ha in western Spain. This model couples a two layer (canopy and understory) vertical local closure energy balance scheme, a hydrologic model and a carbon uptake and vegetation growth component, and it was run using a synthetic daily climate dataset generated by a stochastic weather generator, which reproduced the range of climatic variations observed under mediterranean current climate. The modelling results reproduced satisfactorily the seasonality effects of climate as precipitation and temperatures, as well as annual and inter-annual variations of pasture production. Spatial variations of pasture production were largely controlled by topographic and tree effects, showing medium-low values depending of considered areas. These low values require introduction of feed to

  8. 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.

  9. 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.

  10. Novel Natural Allelic Variations at the Rht-1 Loci in Wheat

    Institute of Scientific and Technical Information of China (English)

    Aixia Li; HongQing Ling; Aimin Zhang; Wenlong Yang; Xueyuan Lou; Dongcheng Liu; Jiazhu Sun; Xiaoli Guo; Jing Wang; Yiwen Li; Kehui Zhan

    2013-01-01

    Plant height is an important agronomic trait. Dramatic increase in wheat yield during the“green revolution”is mainly due to the widespread utilization of the Reduced height (Rht)-1 gene. We analyzed the natural allelic variations of three homoeologous loci Rht-A1, Rht-B1, and Rht-D1 in Chinese wheat (Triticum aestivum L.) micro-core collections and the Rht-B1/D1 genotypes in over 1,500 bred cultivars and germplasms using a modified EcoTILLING. We identified six new Rht-A1 allelic variations (Rht-A1b-g), eight new Rht-B1 allelic variations (Rht-B1h-o), and six new Rht-D1 allelic variations (Rht-D1e-j). These allelic variations contain single nucleotide polymorphisms (SNPs) or small insertions and deletions in the coding or uncoding regions, involving two frame-shift mutations and 15 missenses. Of which, Rht-D1e and Rht-D1h resulted in the loss of interactions of GID1-DELLA-GID2, Rht-B1i could increase plant height. We found that the Rht-B1h contains the same SNPs and 197 bp fragment insertion as reported in Rht-B1c. Further detection of Rht-B1h in Tibet wheat germplasms and wheat relatives indicated that Rht-B1c may originate from Rht-B1h. These results suggest rich genetic diversity at the Rht-1 loci and provide new resources for wheat breeding.

  11. New findings on natural climate variations; Neue Erkenntnisse ueber natuerliche Klimaschwankungen

    Energy Technology Data Exchange (ETDEWEB)

    Mangini, A. [Heidelberger Akademie der Wissenschaften, Heidelberg (Germany)

    2002-04-01

    Ice core drilling, sediment samples and other geological archives have shown that there is a constant alternation between ice ages and warm ages. The resuts so far suggest that this, as well as the current global heating of the earth surface, is caused at least partly by variations in the solar magnetic field. [German] Wie Eiskernbohrungen, Sedimentproben und andere geologische Archive belegen, findet ein staendiger Wechsel von Eis- und Warmzeiten statt. Nach bisherigen Erkenntnissen ist anzunehmen, dass ebenso wie diese langfristige Klimaschwankung auch die gegenwaertige Erwaermung der Erdoberflaeche zumindest teilweise durch Veraenderungen des Sonnenmagnetfeldes verursacht wird. (orig.)

  12. Bats and wind energy in Canada : causes, consequences and variation of fatalities

    Energy Technology Data Exchange (ETDEWEB)

    Barclay, R.; Baerwald, E. [Calgary Univ., AB (Canada). Dept. of Biology

    2008-07-01

    This presentation discussed various aspects of bat mortalities that occur at wind turbines. The majority of bat fatalities related to wind turbines take place in the Fall among Hoary, Silver-haired, and Eastern red bat species. The fatality rate varies geographically. Migratory routes explain the geographic variations of bats. Tall wind turbines kill more bats than birds. Activity and fatality rates vary geographically. Small-scale geographic patterns were discussed along with bat mortality rates at different wind farm facilities. Higher turbines are known to disrupt bat activities. During a 1-year period in Alberta only 189 bird mortalities were recorded compared to 1775 bat mortalities. Across North America, 3940 bats died in collisions with wind turbines compared to only 1241 birds. It was concluded that monitoring studies conducted from the ground do not fully indicate the risks of wind turbines to bats. tabs., figs.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    BACKGROUND: Studies have shown associations between mortality and long-term exposure to particulate matter air pollution. Few cohort studies have estimated the effects of the elemental composition of particulate matter on mortality. OBJECTIVES: Our aim was to study the association between natural...... 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 <10 µm (PM10) were estimated using land-use regression models. Cohort-specific statistical analyses of...... the associations between mortality and air pollution were conducted using Cox proportional hazards models using a common protocol followed by meta-analysis. RESULTS: The total study population consisted of 291,816 participants, of which 25,466 died from a natural cause during follow-up (average time...

  14. Evaporation in the Atacama Desert: An empirical study of spatio-temporal variations and their causes

    Science.gov (United States)

    Houston, John

    2006-11-01

    SummaryThe Atacama Desert is hyper-arid, and areas where adequate moisture exists for evaporation are spatially highly restricted. Nevertheless, water resources exist and their evaluation requires knowledge of this elusive but important component of the hydrological cycle. Evaporation may occur in four typical areas: rivers and associated riparian zones, localized springs, large playas and extensive areas of bare soil after infrequent precipitation events. Transpiration is locally possible where moisture is sufficiently close to the surface to allow phreatophytes or scarce grass cover to grow, but virtually no information is available for quantification. Pan evaporation data from 11 stations for the period 1977-1991 is analyzed and complemented by analysis of an evaporation study conducted in the Salar de Atacama during 1987/1988. The results show that pan evaporation, and hence maximum potential evaporation may be considered largely a function of maximum temperature and elevation as well as density of the evaporating fluid. Actual evaporation is limited by available moisture and diminishes rapidly as the level of soil moisture saturation drops below the soil surface, extinguishing at ca. 2 m depth. Evaporation is greatest during the summer, but at higher elevations convective cloudiness develops during January and February reducing evaporating rates at a time when significant precipitation may occur. Inter-annual variations in pan evaporation are considerable and weakly correlated with ENSO, but variations in actual evaporation are damped by comparison. Regression equations are developed which have widespread applicability and may be used to estimate evaporation in areas where no site-specific data exists.

  15. 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. PMID:24589220

  16. Environmental and genetic interactions reveal FLOWERING LOCUS C as a modulator of the natural variation for the plasticity of flowering in Arabidopsis.

    Science.gov (United States)

    Méndez-Vigo, Belén; Savic, Marija; Ausín, Israel; Ramiro, Mercedes; Martín, Beatriz; Picó, F Xavier; Alonso-Blanco, Carlos

    2016-02-01

    The timing of flowering initiation depends strongly on the environment, a property termed as the plasticity of flowering. Such plasticity determines the adaptive potential of plants because it provides phenotypic buffer against environmental changes, and its natural variation contributes to evolutionary adaptation. We addressed the genetic mechanisms of the natural variation for this plasticity in Arabidopsis thaliana by analysing a population of recombinant inbred lines derived from Don-0 and Ler accessions collected from distinct climates. Quantitative trait locus (QTL) mapping in four environmental conditions differing in photoperiod, vernalization treatment and ambient temperature detected the folllowing: (i) FLOWERING LOCUS C (FLC) as a large effect QTL affecting flowering time differentially in all environments; (ii) numerous QTL displaying smaller effects specifically in some conditions; and (iii) significant genetic interactions between FLC and other loci. Hence, the variation for the plasticity of flowering is determined by a combination of environmentally sensitive and specific QTL, and epistasis. Analysis of FLC from Don identified a new and more active allele likely caused by a cis-regulatory deletion covering the non-coding RNA COLDAIR. Further characterization of four FLC natural alleles showed different environmental and genetic interactions. Thus, FLC appears as a major modulator of the natural variation for the plasticity of flowering to multiple environmental factors. PMID:26173848

  17. On the Nature of Variations in Density and Composition within TATB-based Plastic Bonded Explosives

    International Nuclear Information System (INIS)

    Initiation of insensitive high explosives is affected by porosity in the 100 nm to micron size range. It is also recognized that as-pressed plastic bonded explosives (PBX) are heterogeneous in composition and density at much coarser length scale (10 microns-100 microns). However, variations in density and composition of these explosives have been poorly characterized. Here, we characterize the natural variations in composition and density of TATB-based PBX LX-17 with synchrotron radiation tomography and ultra small angle x-ray scattering. Large scale variations in composition occur as a result of binder enrichment at the prill particle boundaries. The pore fraction is twice as high in the prill particle as in the boundary. The pore distribution is bimodal, with small pores of 50-100 nm in radius and a broader distribution of pores in the 0.5-1.5 micron size range. The higher pore density within the prill particle is attributed to contact asperities between the crystallites that might inhibit complete consolidation and binder infiltration

  18. 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.

  19. 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.

  20. Synthetic biology of metabolism: using natural variation to reverse engineer systems.

    Science.gov (United States)

    Kliebenstein, Daniel J

    2014-06-01

    A goal of metabolic engineering is to take a plant and introduce new or modify existing pathways in a directed and predictable fashion. However, existing data does not provide the necessary level of information to allow for predictive models to be generated. One avenue to reverse engineer the necessary information is to study the genetic control of natural variation in plant primary and secondary metabolism. These studies are showing that any engineering model will have to incorporate information about 1000s of genes in both the nuclear and organellar genome to optimize the function of the introduced pathway. Further, these genes may interact in an unpredictable fashion complicating any engineering approach as it moves from the one or two gene manipulation to higher order stacking efforts. Finally, metabolic engineering may be influenced by a previously unrecognized potential for a plant to measure the metabolites within it. In combination, these observations from natural variation provide a beginning to help improve current efforts at metabolic engineering. PMID:24699221

  1. Autism as a natural human variation: reflections on the claims of the neurodiversity movement.

    Science.gov (United States)

    Jaarsma, Pier; Welin, Stellan

    2012-03-01

    Neurodiversity has remained a controversial concept over the last decade. In its broadest sense the concept of neurodiversity regards atypical neurological development as a normal human difference. The neurodiversity claim contains at least two different aspects. The first aspect is that autism, among other neurological conditions, is first and foremost a natural variation. The other aspect is about conferring rights and in particular value to the neurodiversity condition, demanding recognition and acceptance. Autism can be seen as a natural variation on par with for example homosexuality. The broad version of the neurodiversity claim, covering low-functioning as well as high-functioning autism, is problematic. Only a narrow conception of neurodiversity, referring exclusively to high-functioning autists, is reasonable. We will discuss the effects of DSM categorization and the medical model for high functioning autists. After a discussion of autism as a culture we will analyze various possible strategies for the neurodiversity movement to claim extra resources for autists as members of an underprivileged culture without being labelled disabled or as having a disorder. We will discuss their vulnerable status as a group and what obligation that confers on the majority of neurotypicals. PMID:21311979

  2. Measurement of the natural variation of 13C/12C isotope ratio in organic samples

    International Nuclear Information System (INIS)

    The isotopic ratio analysis for 13C/12C by mass spectrometry using a 'Working standard' allows the study of 13C natural variation in organic material, with a total analytical error of less than 0,2%. Equations were derived in order to determine 13C/12C and 18O/16O ratios related to the 'working standard' CENA-std and to the international standard PDB. Isotope ratio values obtained with samples prepared in two different combustion apparatus were compared; also the values obtained preparing samples by acid decomposition of carbonaceous materials were compared with the values obtained in different international laboratories. Utilizing the methodology proposed, several leaves collected at different heights of different vegetal species, found 'inside' and 'outside' of the Ducke Forest Reserve, located in the Amazon region, are analysed. It is found that the 13C natural variation depends upon metabolic process and environmental factors, both being factors which may be qualified as parcial influences on the CO2 cycle in the forest. (author)

  3. Natural variation in expression of genes associated with 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. The causes of variation in the presence of genetic covariance between sexual traits and preferences.

    Science.gov (United States)

    Fowler-Finn, Kasey D; Rodríguez, Rafael L

    2016-05-01

    Mating traits and mate preferences often show patterns of tight correspondence across populations and species. These patterns of apparent coevolution may result from a genetic association between traits and preferences (i.e. trait-preference genetic covariance). We review the literature on trait-preference covariance to determine its prevalence and potential biological relevance. Of the 43 studies we identified, a surprising 63% detected covariance. We test multiple hypotheses for factors that may influence the likelihood of detecting this covariance. The main predictor was the presence of genetic variation in mate preferences, which is one of the three main conditions required for the establishment of covariance. In fact, 89% of the nine studies where heritability of preference was high detected covariance. Variables pertaining to the experimental methods and type of traits involved in different studies did not greatly influence the detection of trait-preference covariance. Trait-preference genetic covariance appears to be widespread and therefore represents an important and currently underappreciated factor in the coevolution of traits and preferences. PMID:25808899

  5. A general approximate method for the groundwater response problem caused by water level variation

    Science.gov (United States)

    Jiang, Qinghui; Tang, Yuehao

    2015-10-01

    The Boussinesq equation (BEQ) can be used to describe groundwater flow through an unconfined aquifer. Based on 1D BEQ, we present a general approximate method to predict the water table response in a semi-infinite aquifer system with a vertical or sloping boundary. A decomposition method is adopted by separating the original problem into a linear diffusion equation (DE) and two correction functions. The linear DE satisfies all the initial and boundary conditions, reflecting the basic characteristics of groundwater movement. The correction functions quantitatively measure the errors due to the degeneration from the original BEQ to a linear DE. As the correction functions must be linearized to obtain analytical solution forms, the proposed method is an approximate approach. In the case studies, we apply this method to four different situations of water level variation (i.e., constant, sudden, linear and periodic change) resting on vertical or sloping boundaries. The results are compared against numerical results, field data and other analytical solutions, which demonstrate that the proposed method has a good accuracy and versatility over a wide range of applications.

  6. Neutron Absorbing Ability Variation in Neutron Absorbing Material Caused by the Neutron Irradiation in Spent Fuel Storage Facility

    International Nuclear Information System (INIS)

    In spent fuel storage facility like high density spent fuel storage racks and dry storage casks, spent fuels are stored with neutron absorbing materials installed as a part of those facilities, and they are used for absorbing neutrons emitted from spent fuels. Usually structural material with neutron absorbing material of racks and casks are located around spent fuels, so it is irradiated by neutrons for long time. Neutron absorbing ability could be changed by the variation of nuclide composition in neutron absorbing material caused by the irradiation of neutrons. So, neutron absorbing materials are continuously faced with spent fuels with boric acid solution or inert gas environment. Major nuclides in neutron absorbing material are Al27, C12, B11, B10 and they are changed to numerous other ones as radioactive decay or neutron absorption reaction. The B10 content in neutron absorbing material dominates the neutron absorbing ability, so, the variation of nuclide composition including the decrease of B10 content is the critical factor on neutron absorbing ability. In this study, neutron flux in spent fuel, the activation of neutron absorbing material and the variation of nuclide composition are calculated. And, the minimum neutron flux causing the decrease of B10 content is calculated in spent fuel storage facility. Finally, the variation of neutron multiplication factor is identified according to the one of B10 content in neutron absorbing material. The minimum neutron flux to impact the neutron absorbing ability is 1010 order, however, usual neutron flux from spent fuel is 108 order. Therefore, even though neutron absorbing material is irradiated for over 40 years, B10 content is little decreased, so, initial neutron absorbing ability could be kept continuously

  7. 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)

  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

    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...

  9. 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

    lead to a loss of accuracy. As a performance test of a CG-5 for applications of time-lapse gravity in hydrology, we have measured the change in water storage in an indoor basin. The experiment was designed to resemble a field application, e.g. a pumping test, a forced infiltration experiment or......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...... sensitivity of 1μGal, corresponding to a layer of 0.024 m of water in an infinitely extended horizontal sheet. For gravity surveys using relative gravity meters, the precision is highly dependent on the methods used to operate the gravimeter in the field. Systematic errors, which are difficult to detect, can...

  10. 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.

  11. 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.

  12. Variation of Natural Streamflow since 1470 in the Middle Yellow River, China

    Directory of Open Access Journals (Sweden)

    Jin-Ren Ni

    2009-11-01

    Full Text Available Nowadays, as the available water resources throughout the World are becoming depleted, in order to manage and plan water resource better, more and more attention is being paid into the fluctuating characteristics of water discharges. However, the preexisting research was mainly focused on the last half century. In this paper, the natural streamflow observed since 1470 at the Sanmenxia station in the middle Yellow River basin was collected, and the methods of variation coefficient, moving average, Mann-Kendall test and wavelet transform were applied to analyze the dynamic characteristics of the streamflow. The results showed that, (1 between 1470 and 2007, the natural streamflow changed 200–919 ×108 m3, and water discharge varied moderately; (2 in the middle Yellow River basin, it appears that the most severe and most persistent droughts during circa 1868–1990, the periods of 1470s–1490s, 1920s–1930s and 1990s–2000s also presented the condition of sustained low flows; (3 the natural streamflow series shows increasing and decreasing trends during the periods of 1470–1880 and 1881–2007, respectively, but both trends are not significant at >95% confidence; in addition, it is still found the streamflow series shows abrupt changes circa 1845, 1935 and 1960, respectively; (4 within a 250-year scale, there are circa 11, 26, 67 and 120-year periods for natural streamflow at the Sanmenxia station, and the periodicity of the 120-year one is the strongest. The dynamic characteristics of natural streamflow is the comprehensive result by many influencing factors, such as precipitation, temperature, El Niño-Southern Oscillation, sunspots, human activity etc.

  13. 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.

  14. Neutrons Reveal How Nature Uses Structural Themes and Variations in Biological Regulation

    International Nuclear Information System (INIS)

    Full text: Healthy cellular function requires tight regulation of a multitude of bio-molecular interactions and processes, often in response to external stimuli. Nature has a number of second messengers that are released inside cells in response to first messengers, such as hormones binding at the cell surface. Divalent calcium and the cyclic nucleotides (cAMP and cGMP) are among natures second messengers that often serve to regulate the activity of protein kinases, the enzymes that catalyze the attachment of phosphate groups to other proteins in order to modulate their functions. Neutron contrast variation is an excellent tool for studying the interactions of the second messenger receptor proteins and their targets. We have been using neutrons to study these interactions for some time, and our most recent results have focused on the how nature utilizes different isoforms of the same protein to accomplish similar but distinct functions. I will describe recent results that provide insights into the differences and similarities in protein structure and function in second messenger mediated signaling, with a special focus on the different isoforms of the muscle regulatory complex troponin and the cGMP- and cAMP-protein kinases. (author)

  15. 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.

  16. Interannual variation of the Philippines affecting tropical cyclone intensity and its possible causes

    Science.gov (United States)

    Choi, Ki-Seon; Kim, Baek-Jo; Kang, Sung-Dae; Kim, Hae-Dong

    2015-10-01

    This study analyzed changes in tropical cyclone (TC) intensity for the past 62 years (1951-2012) by calculating annual average value of central pressure (CP) of TCs that affected the Philippines from July to September. Although TC intensity slightly weakened for the last 62 years, it was not statistically significant. In order to examine the causes of changes in intensity of TCs that influenced the Philippines, nine low CP years and nine high CP years among the 62 years were selected to analyze differences between the two groups. TCs largely occurred in the southeastern quadrant of tropical and subtropical western North Pacific during low CP years and tended to move to the Philippines from the far sea in the southeast of the nation. In differences in deep-layer-mean wind between the two groups, western North Pacific subtropical high (WNPSH) did not develop toward the middle latitudes of East Asia but toward the low latitudes of the region during low CP years. Therefore, TCs occurred in the southeastern quadrant of tropical and subtropical western North Pacific, triggering its movement of long distance westward toward the Philippines. As positive anomalies in precipitable water and at 600 hPa relative humidity, 850 hPa air temperature, and sea surface temperature continued to the Philippines from the southeastern quadrant, a favorable environment where intensity of TCs can be strengthened while they move to the Philippines during low CP years has been formed. In the end, because WNPSH developed toward the low latitudes during low CP years, anomalous easterlies that strengthened in the southern regions of WNPSH blew to the Philippines, and SST in the sea near the nation was heightened. Therefore, because TCs were able to obtain sufficient energy from the relatively warm sea while TCs moved a long distance to the Philippines, TC intensity was able to be strengthened.

  17. Variation of haemoglobin extinction coefficients can cause errors in the determination of haemoglobin concentration measured by near-infrared spectroscopy

    Science.gov (United States)

    Kim, J. G.; Liu, H.

    2007-10-01

    Near-infrared spectroscopy or imaging has been extensively applied to various biomedical applications since it can detect the concentrations of oxyhaemoglobin (HbO2), deoxyhaemoglobin (Hb) and total haemoglobin (Hbtotal) from deep tissues. To quantify concentrations of these haemoglobin derivatives, the extinction coefficient values of HbO2 and Hb have to be employed. However, it was not well recognized among researchers that small differences in extinction coefficients could cause significant errors in quantifying the concentrations of haemoglobin derivatives. In this study, we derived equations to estimate errors of haemoglobin derivatives caused by the variation of haemoglobin extinction coefficients. To prove our error analysis, we performed experiments using liquid-tissue phantoms containing 1% Intralipid in a phosphate-buffered saline solution. The gas intervention of pure oxygen was given in the solution to examine the oxygenation changes in the phantom, and 3 mL of human blood was added twice to show the changes in [Hbtotal]. The error calculation has shown that even a small variation (0.01 cm-1 mM-1) in extinction coefficients can produce appreciable relative errors in quantification of Δ[HbO2], Δ[Hb] and Δ[Hbtotal]. We have also observed that the error of Δ[Hbtotal] is not always larger than those of Δ[HbO2] and Δ[Hb]. This study concludes that we need to be aware of any variation in haemoglobin extinction coefficients, which could result from changes in temperature, and to utilize corresponding animal's haemoglobin extinction coefficients for the animal experiments, in order to obtain more accurate values of Δ[HbO2], Δ[Hb] and Δ[Hbtotal] from in vivo tissue measurements.

  18. Variation of haemoglobin extinction coefficients can cause errors in the determination of haemoglobin concentration measured by near-infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J G; Liu, H [Joint Graduate Program in Biomedical Engineering, University of Texas at Arlington/University of Texas Southwestern Medical Center at Dallas, Arlington, TX 76019 (United States)

    2007-10-21

    Near-infrared spectroscopy or imaging has been extensively applied to various biomedical applications since it can detect the concentrations of oxyhaemoglobin (HbO{sub 2}), deoxyhaemoglobin (Hb) and total haemoglobin (Hb{sub total}) from deep tissues. To quantify concentrations of these haemoglobin derivatives, the extinction coefficient values of HbO{sub 2} and Hb have to be employed. However, it was not well recognized among researchers that small differences in extinction coefficients could cause significant errors in quantifying the concentrations of haemoglobin derivatives. In this study, we derived equations to estimate errors of haemoglobin derivatives caused by the variation of haemoglobin extinction coefficients. To prove our error analysis, we performed experiments using liquid-tissue phantoms containing 1% Intralipid in a phosphate-buffered saline solution. The gas intervention of pure oxygen was given in the solution to examine the oxygenation changes in the phantom, and 3 mL of human blood was added twice to show the changes in [Hb{sub total}]. The error calculation has shown that even a small variation (0.01 cm{sup -1} mM{sup -1}) in extinction coefficients can produce appreciable relative errors in quantification of {delta}[HbO{sub 2}], {delta}[Hb] and {delta}[Hb{sub total}]. We have also observed that the error of {delta}[Hb{sub total}] is not always larger than those of {delta}[HbO{sub 2}] and {delta}[Hb]. This study concludes that we need to be aware of any variation in haemoglobin extinction coefficients, which could result from changes in temperature, and to utilize corresponding animal's haemoglobin extinction coefficients for the animal experiments, in order to obtain more accurate values of {delta}[HbO{sub 2}], {delta}[Hb] and {delta}[Hb{sub total}] from in vivo tissue measurements.

  19. Variation of haemoglobin extinction coefficients can cause errors in the determination of haemoglobin concentration measured by near-infrared spectroscopy

    International Nuclear Information System (INIS)

    Near-infrared spectroscopy or imaging has been extensively applied to various biomedical applications since it can detect the concentrations of oxyhaemoglobin (HbO2), deoxyhaemoglobin (Hb) and total haemoglobin (Hbtotal) from deep tissues. To quantify concentrations of these haemoglobin derivatives, the extinction coefficient values of HbO2 and Hb have to be employed. However, it was not well recognized among researchers that small differences in extinction coefficients could cause significant errors in quantifying the concentrations of haemoglobin derivatives. In this study, we derived equations to estimate errors of haemoglobin derivatives caused by the variation of haemoglobin extinction coefficients. To prove our error analysis, we performed experiments using liquid-tissue phantoms containing 1% Intralipid in a phosphate-buffered saline solution. The gas intervention of pure oxygen was given in the solution to examine the oxygenation changes in the phantom, and 3 mL of human blood was added twice to show the changes in [Hbtotal]. The error calculation has shown that even a small variation (0.01 cm-1 mM-1) in extinction coefficients can produce appreciable relative errors in quantification of Δ[HbO2], Δ[Hb] and Δ[Hbtotal]. We have also observed that the error of Δ[Hbtotal] is not always larger than those of Δ[HbO2] and Δ[Hb]. This study concludes that we need to be aware of any variation in haemoglobin extinction coefficients, which could result from changes in temperature, and to utilize corresponding animal's haemoglobin extinction coefficients for the animal experiments, in order to obtain more accurate values of Δ[HbO2], Δ[Hb] and Δ[Hbtotal] from in vivo tissue measurements

  20. Analyses of CO2 Time Variation Records in Naturally Ventilated Occupied Spaces

    Directory of Open Access Journals (Sweden)

    Ivanov Martin

    2014-06-01

    Full Text Available The present paper concerns the results obtained in a human subject experimental study, regarding the predefined occupant behavior with respect to aerating activities of a naturally ventilated space. During the experiment, various scenarios were investigated of different occupant’s behavior patterns with regard to the degree of window opening. Indoor air temperature, relative humidity and CO2 volume fraction, were continuously measured and recorded. CO2 concentration time variation records were analyzed separately and the time change of this parameter was considered as a main indicator to distinguish the periods of infiltration only and the periods of conscious aeration activities, performed by the occupants. The developed evaluation procedures as well as the key results from the analyses are discussed in the paper.

  1. Spatio-temporal distribution and natural variation of metabolites in citrus fruits.

    Science.gov (United States)

    Wang, Shouchuang; Tu, Hong; Wan, Jian; Chen, Wei; Liu, Xianqing; Luo, Jie; Xu, Juan; Zhang, Hongyan

    2016-05-15

    To study the natural variation and spatio-temporal accumulation of citrus metabolites, liquid chromatography tandem mass spectrometry (LC-MS) based metabolome analysis was performed on four fruit tissues (flavedo, albedo, segment membrane and juice sacs) and different Citrus species (lemon, pummelo and grapefruit, sweet orange and mandarin). Using a non-targeted metabolomics approach, more than 2000 metabolite signals were detected, from which more than 54 metabolites, including amino acids, flavonoids and limonoids, were identified/annotated. Differential accumulation patterns of both primary metabolites and secondary metabolites in various tissues and species were revealed by our study. Further investigation indicated that flavedo accumulates more flavonoids while juice sacs contain more amino acids. Besides this, cluster analysis based on the levels of metabolites detected in 47 individual Citrus accessions clearly grouped them into four distinct clusters: pummelos and grapefruits, lemons, sweet oranges and mandarins, while the cluster of pummelos and grapefruits lay distinctly apart from the other three species. PMID:26775938

  2. Compounds of Natural Origin and Acupuncture for the Treatment of Diseases Caused by Estrogen Deficiency.

    Science.gov (United States)

    Thakur, Abhishek; Mandal, Subhash C; Banerjee, Sugato

    2016-06-01

    A predominant number of diseases affecting women are related to female hormones. In most of the cases, these diseases are reported to be associated with menstrual problems. These diseases affect female reproductive organs such as the breast, uterus, and ovaries. Estrogen is the main hormone responsible for the menstrual cycle, so irregular menstruation is primarily due to a disturbance in estrogen levels. Estrogen imbalance leads to various pathological conditions in premenopausal women, such as endometriosis, breast cancer, colorectal cancer, prostate cancer, poly cysts, intrahepatic cholestasis of pregnancy, osteoporosis, cardiovascular diseases, obesity, etc. In this review, we discuss common drug targets and therapeutic strategies, including acupuncture and compounds of natural origin, for the treatment of diseases caused by estrogen deficiency. PMID:27342884

  3. 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.

  4. Natural variation of root exudates in Arabidopsis thaliana-linking metabolomic and genomic data.

    Science.gov (United States)

    Mönchgesang, Susann; Strehmel, Nadine; Schmidt, Stephan; Westphal, Lore; Taruttis, Franziska; Müller, Erik; Herklotz, Siska; Neumann, Steffen; Scheel, Dierk

    2016-01-01

    Many metabolomics studies focus on aboveground parts of the plant, while metabolism within roots and the chemical composition of the rhizosphere, as influenced by exudation, are not deeply investigated. In this study, we analysed exudate metabolic patterns of Arabidopsis thaliana and their variation in genetically diverse accessions. For this project, we used the 19 parental accessions of the Arabidopsis MAGIC collection. Plants were grown in a hydroponic system, their exudates were harvested before bolting and subjected to UPLC/ESI-QTOF-MS analysis. Metabolite profiles were analysed together with the genome sequence information. Our study uncovered distinct metabolite profiles for root exudates of the 19 accessions. Hierarchical clustering revealed similarities in the exudate metabolite profiles, which were partly reflected by the genetic distances. An association of metabolite absence with nonsense mutations was detected for the biosynthetic pathways of an indolic glucosinolate hydrolysis product, a hydroxycinnamic acid amine and a flavonoid triglycoside. Consequently, a direct link between metabolic phenotype and genotype was detected without using segregating populations. Moreover, genomics can help to identify biosynthetic enzymes in metabolomics experiments. Our study elucidates the chemical composition of the rhizosphere and its natural variation in A. thaliana, which is important for the attraction and shaping of microbial communities. PMID:27363486

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

    Science.gov (United States)

    Xu, Pei; Moshelion, Menachem; Wu, XiaoHua; Halperin, Ofer; Wang, BaoGen; Luo, Jie; Wallach, Rony; Wu, Xinyi; Lu, Zhongfu; Li, Guojing

    2015-01-01

    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 different 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. PMID:26579145

  6. 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.

  7. Genetic variation of natural orchid phalaenopsis amabilis (L.) blume produce gamma ray irradiation

    International Nuclear Information System (INIS)

    New cultivars of Phalaenopsis amabilis (L.) Blume were obtained through gamma-rays Co-60 irradiation. The result showed phenotypic variation which justifies a molecular biology observation to investigate whether the variation was caused by the change on cultivar’s genotypic traits. A study to describe the genetic variability among individuals of the irradiated cultivars was then conducted using RAPD Technique. The materials used were cultivars obtained by 0, 15, 20, 25, 20+20 and 40 Gray irradiations. DNA genome of each plant was isolated and was amplified with 22 primers randomly. The PCR analysis was done with 1.5 % agarose. The DNA analysis used 8 selected primers out of 22. Polymorphism and molecular diversity were analyzed with Nei’s gene diversity method through GenAlex 6.1 program. The study showed that genetic diversity might be detected at the early growth stage of the gamma ray Co-60 irradiated cultivars using RAPD, and irradiation dose of 15 and 40 Gray gave high genetic diversity compared to control. (author)

  8. CAUSES AND EFFECTS OF NATURAL ENVIRONMENT DEGRADATION IN THE HYDROGRAPHIC BASIN OF RIVER NEAJLOV

    Directory of Open Access Journals (Sweden)

    Luminita Doinea

    2010-01-01

    Full Text Available The paper deals with acute problems of pollution sources and the pressures that these put on the natural environment ina traditionally degraded area due to the development of polluting industries and agricultural activities that operate withoverused and outdated equipment.The case study presents an overview of the hydrographic river basin Neajlov by describing its characteristics and anassessment of the consequences caused by intensive development of agriculture and the industry of oil extraction andprocessing on the structure and function of ecological systems in the basin.The grave pollution of the Dambovnic, a tributary river to Neajlov river, is emphasized as a consequence of thedischarge of wastewater containing high concentrations of pollutants created by the industry of the area, but alsoproduced by accidental pollution. This greatly impacts the ecological status of the water system Dâmbovnic.This paper is a first evaluation in finding solutions for the environmental damage created in the past, to ensuresustainable use of natural resources in the future.

  9. Experimental evolution can unravel the complex causes of natural selection in clinical infections.

    Science.gov (United States)

    Brockhurst, Michael A

    2015-06-01

    It is increasingly clear that rapid evolutionary dynamics are an important process in microbial ecology. Experimental evolution, wherein microbial evolution is observed in real-time, has revealed many instances of appreciable evolutionary change occurring on very short timescales of a few days or weeks in response to a variety of biotic and abiotic selection pressures. From clinical infections, including the chronic bacterial lung infections associated with cystic fibrosis that form a focus of my research, there is now abundant evidence suggesting that rapid evolution by infecting microbes contributes to host adaptation, treatment failure and worsening patient prognosis. However, disentangling the drivers of natural selection in complex infection environments is extremely challenging and limits our understanding of the selective pressures acting upon microbes in infections. Controlled evolution experiments can make a vital contribution to this by determining the causal links between predicted drivers of natural selection and the evolutionary responses of microbes. Integration of experimental evolution into studies of clinical infections is a key next step towards a better understanding of the causes and consequences of rapid microbial evolution in infections, and discovering how these evolutionary processes might be influenced to improve patient health.A video of this Prize Lecture, presented at the Society for General Microbiology Annual Conference 2015, can be viewed via this link: Michael A. Brockhurst https://www.youtube.com/watch?v=N1bodVSl27E. PMID:25957311

  10. The Natural Product Citral Can Cause Significant Damage to the Hyphal Cell Walls of Magnaporthe grisea

    Directory of Open Access Journals (Sweden)

    Rong-Yu Li

    2014-07-01

    Full Text Available In order to find a natural alternative to the synthetic fungicides currently used against the devastating rice blast fungus, Magnaporthe grisea, this study explored the antifungal potential of citral and its mechanism of action. It was found that citral not only inhibited hyphal growth of M. grisea, but also caused a series of marked hyphal morphological and structural alterations. Specifically, citral was tested for antifungal activity against M. grisea in vitro and was found to significantly inhibit colony development and mycelial growth with IC50 and IC90 values of 40.71 and 203.75 μg/mL, respectively. Furthermore, citral reduced spore germination and germ tube length in a concentration-dependent manner. Following exposure to citral, the hyphal cell surface became wrinkled with folds and cell breakage that were observed under scanning electron microscopy (SEM. There was damage to hyphal cell walls and membrane structures, loss of villous-like material outside of the cell wall, thinning of the cell wall, and discontinuities formed in the cell membrane following treatment based on transmission electron microscopy (TEM. This increase in chitinase activity both supports the morphological changes seen in the hyphae, and also suggests a mechanism of action. In conclusion, citral has strong antifungal properties, and treatment with this compound is capable of causing significant damage to the hyphal cell walls of M. grisea.

  11. Late quaternary paleo-climatic records from Alaskan Loess: Identifying causes of natural climate variability

    International Nuclear Information System (INIS)

    Magnetic susceptibility profiling and magnetic remanence studies, x-ray sedigraph analysis, scanning electron microscope image studies, tephrochronology, and fission-track dating of thick loess deposits in Alaska reveal a continuous record of the chronology and pattern of past climate changes at high latitudes. Long-term climate changes in Alaska appear to have closely followed global patterns over at least the last 200,000 years. Radiocarbon and fission-track dating demonstrate agreement between the timing of climate changes recorded in terrestrial loess deposits and records from marine and ice cores. Spectral analyses of loess proxy climate time-series reveal power at orbital frequencies, providing evidence for the Milankovitch model of climate change. Many short-term climate events, lasting only 102 - 103 years, are also recorded in loess sections. Some of these short-term events appear to reflect transient changes in global atmospheric CO2 contents of 25-50% documented by studies of ice cores, and provide evidence for changes in the global Greenhouse effect due to natural variations of atmospheric CO2 content

  12. Identified Natural Hazards May Cause Adverse Impact on Sustainability of Desalination Plants in Red Sea

    Science.gov (United States)

    Aburizaiza, O. S.; Zaigham, N. A.; Nayyar, Z. A.; Mahar, G. A.; Siddique, A.; Eusufi, S. N.

    2011-12-01

    The Red Sea and its surrounding countries have harsh arid climatic conditions where fast growth of the socio-economic activities and rapid change of lifestyle have caused tremendous stress on water to the level of acute crisis. To meet the water demands, the Red Sea countries have adopted seawater desalination giving priority against their land-based resources. Saudi Arabia is the largest desalinated-water producers in the Red Sea and has practically no adequate backup plan in case of sudden unforeseen emergency. Out of about 3.64 million m3/day, Saudi Arabia is alone being desalinated about 3.29 m3/day seawater from Red Sea and more projects are in progress. Present integrated research study has identified some of natural and anthropogenic hazards, which may be major threats to the quality of the seawater as well as to the desalination plants themselves. Results of present study reveal that the submarine complex morphologic features may cause the isolation of Red Sea from any of the open sea, the increase in the seismicity trends, the active volcanism causing unique longitudinal as well as transverse deformations of the axial trough particularly in the southern part of the Red Sea, the consistently generating enormous hot-brine tectonic-factory all along the deeper parts of the Red Sea rifting trough and other related issues. Considering the identified odd conditions, the total dependence on seawater desalination may not be worthwhile for sustainable water management strategy and consequent socio-economic developments in future. It is recommended that the priority should also be given mainly in three main disciplines to meet the future water challenges - one, developing reliable backup water management; second, alternate options for the supplementary resources of water; and third, the development and immediate implementation of the water-use conservation strategy plan.

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

    International Nuclear Information System (INIS)

    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

  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. A variational justification of the assumed natural strain formulation of finite elements. I - Variational principles. II - The C(0) four-node plate element

    Science.gov (United States)

    Militello, Carmelo; Felippa, Carlos A.

    1990-01-01

    The assumed natural strain formulation of finite elements is interpreted from a variational standpoint. The approach is based on hybrid extensions of the Reissner-type functional which uses the strains and displacements as independent fields. Consideration is restricted to linear elasticity. The four-node C(0) plate-bending quadrilateral is used as a specific example to illustrate the application of the present interpretation. A key finding is that any change in the strain-displacement interpolation from the variationally consistent interpolation must be associated in some way to the addition of incompatible displacement modes.

  16. 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

  17. 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.

  18. 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. PMID:26825180

  19. Natural variation in cold tolerance in the nematode Pristionchus pacificus: the role of genotype and environment

    Directory of Open Access Journals (Sweden)

    Angela McGaughran

    2014-08-01

    Full Text Available Low temperature is a primary determinant of growth and survival among organisms and almost all animals need to withstand temperature fluctuations in their surroundings. We used the hermaphroditic nematode Pristionchus pacificus to examine variation in cold tolerance in samples collected from 18 widespread locations. Samples were challenged by exposure to both direct and gradual low temperature after culture in the laboratory at 20°C. A short-term acclimation treatment was also applied to assess cold tolerance following a pre-exposure cold treatment. Finally, genotype-by-environment (G × E analysis was performed on a subset of samples cultured at two additional temperatures (15°C and 25°C. P. pacificus displayed a high degree of natural variation in cold tolerance, corresponding to the presence of three distinct phenotypic classes among samples: cold tolerant, non-cold tolerant, cold tolerant plastic. Survival of gradual cold exposure was significantly higher than survival of direct exposure to low temperature and a cold exposure pre-treatment significantly enhanced cold tolerance in some samples. By focusing on a sub-set of well-sampled locations from tropical La Réunion Island, we found evidence of significant effects of genotype and environment on cold tolerance, and we also showed that, within the different Réunion locations sampled, all three phenotypic classes are generally well represented. Taken together, our results show that P. pacificus exhibits a highly plastic tolerance to cold exposure that may be partly driven by differential trait sensitivity in diverse environments.

  20. Tuning polyelectrolyte multilayer structure by exploiting natural variation in fucoidan chemistry.

    Science.gov (United States)

    Ho, Tracey T M; Bremmell, Kristen E; Krasowska, Marta; Stringer, Damien N; Thierry, Benjamin; Beattie, David A

    2015-03-21

    Fucoidan is a sulfated polysaccharide that is extracted primarily from seaweed. The polymer contains a natural variation in chemistry based upon the species of seaweed from which it is extracted. We have used two different fucoidans from two different seaweed species (Fucus vesiculosus - FV; and Undaria pinnatifida - UP) as polyanions for the formation of polysaccharide-based polyelectrolyte multilayers (PEMs), to determine if the chemistry of different fucoidans can be chosen to fine-tune the structure of the polymer film. Partially acetylated chitosan was chosen as the polycation for the work, and the presented data illustrate the effect of secondary hydrogen bonding interactions on PEM build-up and properties. Ellipsometry and quartz crystal microbalance with dissipation monitoring (QCM-D) measurements performed during film build-up enabled detailed measurements of layer thickness, adsorbed mass, and the dynamics of the multilayer formation process. High quality atomic force microscopy (AFM) images revealed the differences in morphology of the PEMs formed from the two fucoidans, and allowed for a more direct layer thickness measurement. X-ray photoelectron spectroscopy (XPS) confirmed the chemistry of the films, and an indication of the altered interactions between chitosan and fucoidan with variation in fucoidan type, but also with layer number. Distinct differences were observed between multilayers formed with the two fucoidans, with those constructed using UP having thinner, denser, less hydrated layers than those constructed using FV. These differences are discussed in the context of their varied chemistry, primarily their difference in molecular weight and degree of acetylation. PMID:25599229

  1. Fluvial filtering of land-to-ocean fluxes: from natural Holocene variations to Anthropocene

    Science.gov (United States)

    Meybeck, Michel; Vörösmarty, Charles

    2005-02-01

    The evolution of river systems and their related fluxes is considered at various time scales: ( i) over the last 18 000 years, under climatic variability control, ( ii) over the last 50 to 200 years (Anthropocene) due to direct human impacts. Natural Holocene variations in time and space depend on ( i) land-to-ocean connections (endorheism, glacial cover, exposure of continental shelf); ( ii) types of natural fluvial filters (e.g., wetlands, lakes, floodplains, estuaries). Anthropocene changes concern ( i) land-ocean connection (e.g., partial to total runoff reduction resulting from water management), ( ii) modification and removal of natural filters, ( iii) creation of new filters, particularly irrigated fields and reservoirs, ( iv) acceleration and/or development of material sources from human activities. The total river basin area directly affected by human activities is of the same order of magnitude ( >40 Mkm) as the total area affected over the last 18 000 years. A tentative analysis of 38 major river systems totaling 55 Mkm is proposed for several criteria: ( i) trajectories of Holocene evolution, ( ii) occurrence of natural fluvial filters, ( iii) present-day fluvial filters: most river basins are unique. Riverine fluxes per unit area are characterized by hot spots that exceed the world average by one order of magnitude. At the Anthropocene (i.e., since 1950), many riverine fluxes have globally increased (sodium, chloride, sulfate, nitrogen, phosphorous, heavy metals), others are stable (calcium, bicarbonate, sediments) or likely to decrease (dissolved silica). Future trajectories of river fluxes will depend on the balance between increased sources of material (e.g., soil erosion, pollution, fertilization), water abstraction for irrigation and the modification of fluvial filters, particularly the occurrence of reservoirs that already intercept half of the water and store at least 30% of river sediment fluxes. In some river systems, retention actually

  2. 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

  3. 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

  4. 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.

  5. Reproductive biology and pollination mechanisms of Epidendrum secundum (Orchidaceae). Floral variation: a consequence of natural hybridization?

    Science.gov (United States)

    Pansarin, E R; Amaral, M C E

    2008-03-01

    The phenology, flower morphology, pollination mechanism and reproductive biology of Epidendrum secundum were studied in a semi-deciduous forest at the Serra do Japi (SJ), and in the Atlantic rain forest of Picinguaba, both natural reserves in the State of São Paulo, southeastern Brazil. E. secundum flowers all year round, with a flowering peak between September and January. This species is either a lithophytic or terrestrial herb in the SJ, whereas, in Picinguaba, it grows mainly in disturbed areas along roadsides. E. secundum is pollinated by several species of diurnal Lepidoptera at both study sites. In Picinguaba, where E. secundum is sympatric with E. fulgens and both share the same pollinators, pollen transference between these two species was recorded. E. secundum is self-compatible but pollinator-dependent. It is inter-compatible with E. fulgens, producing fertile seeds. In contrast to the population of the SJ, in the Picinguaba region, floral morphology is quite variable among plants and some individuals present flowers with characteristics in-between both sympatric species, suggesting that natural hybridization occasionally occurs. The anthropogenic perturbation is probably the cause of the occurrence of E. secundum in the Picinguaba region, enabling its contact with E. fulgens. PMID:18304195

  6. Spatial variation of natural radiation and childhood leukaemia incidence in Great Britain

    International Nuclear Information System (INIS)

    This paper describes an analysis of the geographical variation of childhood leukaemia incidence in Great Britain over a 15 year period in relation to natural radiation (gamma and radon). Data at the level of the 459 district level local authorities in England, Wales and regional districts in Scotland are analysed in two complementary ways: first, by Poisson regressions with the inclusion of environmental covariates and a smooth spatial structure; secondly, by a hierarchical Bayesian model in which extra-Poisson variability is modelled explicitly in terms of spatial and non-spatial components. From this analysis, we deduce a strong indication that a main part of the variability is accounted for by a local neighbourhood 'clustering' structure. This structure is furthermore relatively stable over the 15 year period for the lymphocytic leukaemias which make up the majority of observed cases. We found no evidence of a positive association of childhood leukaemia incidence with outdoor or indoor gamma radiation levels. There is no consistent evidence of any association with radon levels. Indeed, in the Poisson regressions, a significant positive association was only observed for one 5-year period, a result which is not compatible with a stable environmental effect. Moreover, this positive association became clearly non-significant when over-dispersion relative to the Poisson distribution was taken into account. (author)

  7. Analysis of natural ground-water level variations for hydrogeologic conceptualization, Hanford Site, Washington

    Science.gov (United States)

    Nevulis, Richard H.; Davis, Donald R.; Sorooshian, Soroosh

    1989-07-01

    This study involves the analysis of groundwater level time series for the purpose of obtaining details for a conceptual hydrogeologic model at a time when conventional hydraulic stress testing was not feasible due to regulatory considerations. The study area is located in south central Washington in the Pasco Basin which was a candidate site for underground disposal of high-level radioactive nuclear wastes. Advantages of such passive methods of analysis may include relative simplicity, low cost, and avoidance of disturbances typically associated with stress testing of aquifers. Through this approach, natural and incidental man-made groundwater level variations, most of which are quite small, are examined by statistical and analytical methods in conjunction with hydrogeologic models to draw inferences on the hydrogeology. Vertical connectivity of the hydrostratigraphic units is also examined by analyzing groundwater level time series of five units at three piezometer nests. It is concluded that a combination of statistical/analytical approaches used in a complementary fashion can provide useful information about the hydrogeology of a given area. A meaningful analysis requires that there is (1) a source of influence on the groundwater levels, (2) a response to that influence, (3) a sufficiently long data record, and (4) measurement and analytical techniques which allow the detection and identification of the influence and response.

  8. Spatial variation of natural radiation and childhood leukaemia incidence in Great Britain

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Sylvia; Monfort, Christine [Institut National de la Sante et de la Recherche Medicale, Villejuif, 94 (France); Green, Martyn; Muirhead, Colin [National Radiological Protection Board, Chilton (United Kingdom); Draper, Gerald [Oxford Univ., Childhood Cancer Research Group, Oxford (United Kingdom)

    1995-12-31

    This paper describes an analysis of the geographical variation of childhood leukaemia incidence in Great Britain over a 15 year period in relation to natural radiation (gamma and radon). Data at the level of the 459 district level local authorities in England, Wales and regional districts in Scotland are analysed in two complementary ways: first, by Poisson regressions with the inclusion of environmental covariates and a smooth spatial structure; secondly, by a hierarchical Bayesian model in which extra-Poisson variability is modelled explicitly in terms of spatial and non-spatial components. From this analysis, we deduce a strong indication that a main part of the variability is accounted for by a local neighbourhood `clustering` structure. This structure is furthermore relatively stable over the 15 year period for the lymphocytic leukaemias which make up the majority of observed cases. We found no evidence of a positive association of childhood leukaemia incidence with outdoor or indoor gamma radiation levels. There is no consistent evidence of any association with radon levels. Indeed, in the Poisson regressions, a significant positive association was only observed for one 5-year period, a result which is not compatible with a stable environmental effect. Moreover, this positive association became clearly non-significant when over-dispersion relative to the Poisson distribution was taken into account. (author).

  9. Natural variation in Drosophila larval reward learning and memory due to a cGMP-dependent protein kinase

    OpenAIRE

    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 ability. Here, we investigate whether natural variation in the foraging (for) gene in Drosophila melanogaster larvae is important in mediating associa...

  10. Genetic variation within and among naturally regenerating populations of alder (Alnus glutinosa

    Directory of Open Access Journals (Sweden)

    Leon Mejnartowicz

    2011-04-01

    Full Text Available To assess the inter- and intrapopulation genetic variation in the filial generation (F1 of alder (Alnus glutinosa (L. Gaertn., 11 naturally regenerated populations were analysed. Their parental populations (P, represent the whole Polish territory and belong to three phytosociological associations with alder: typical alder swamp forest Carici elongatae-Alnetum (Ce-A; alder riparian forest Circaeo-Alnetum (C-A; and ash-elm riparian forest Fraxino-Ulmetum (F-U. F1 populations are grown in a common-garden experiment (provenance trial. Genotyping of individual trees has been carried out by analysis in a bud tissue allele frequency in the 21 isozyme putative loci of 10 enzymes. Differences between populations in respect to the level of genetic diversity were not high. Genetic diversity measured as the number of effective alleles per locus was the highest (Ne = 1.65 in population Wińsko originating from F-U (where also the inbreeding coefficient was the highest, F = 0.429, and the lowest (Ne = 1.48 in population Sławki from Ce-A. In all investigated populations, observed heterozygosity (Ho = 20% was lower than expected from H-W equilibrium (He = 29%. The highest genetic variation expressed as percentage of polymorphic loci (77.3% was observed in the offspring populations from Ce-A, and the smallest (69.9% in the populations originating from F-U. It seems that the low genetic differentiation between populations is probably connected with long-distance seed dispersal via river systems. Alder seed can be transported over long distances thanks to periodical flooding. There is some gene flow between alder populations, with about 2.5 immigrants successfully entering a population per generation (Nm = 2.55. The level of population subdivision within A. glutinosa was low (Fst = 0.089. There was no significant genetic differentiation between populations from different phytosociological associations. Mantel test exhibited no significant correlation (r = 0

  11. Nuclear genomic control of naturally occurring variation in mitochondrial function in Drosophila melanogaster

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    Jumbo-Lucioni Patricia

    2012-11-01

    Full Text Available Abstract Background Mitochondria are organelles found in nearly all eukaryotic cells that play a crucial role in cellular survival and function. Mitochondrial function is under the control of nuclear and mitochondrial genomes. While the latter has been the focus of most genetic research, we remain largely ignorant about the nuclear-encoded genomic control of inter-individual variability in mitochondrial function. Here, we used Drosophila melanogaster as our model organism to address this question. Results We quantified mitochondrial state 3 and state 4 respiration rates and P:O ratio in mitochondria isolated from the thoraces of 40 sequenced inbred lines of the Drosophila Genetic Reference Panel. We found significant within-population genetic variability for all mitochondrial traits. Hence, we performed genome-wide association mapping and identified 141 single nucleotide polymorphisms (SNPs associated with differences in mitochondrial respiration and efficiency (P ≤1 × 10-5. Gene-centered regression models showed that 2–3 SNPs can explain 31, 13, and 18% of the phenotypic variation in state 3, state 4, and P:O ratio, respectively. Most of the genes tagged by the SNPs are involved in organ development, second messenger-mediated signaling pathways, and cytoskeleton remodeling. One of these genes, sallimus (sls, encodes a component of the muscle sarcomere. We confirmed the direct effect of sls on mitochondrial respiration using two viable mutants and their coisogenic wild-type strain. Furthermore, correlation network analysis revealed that sls functions as a transcriptional hub in a co-regulated module associated with mitochondrial respiration and is connected to CG7834, which is predicted to encode a protein with mitochondrial electron transfer flavoprotein activity. This latter finding was also verified in the sls mutants. Conclusions Our results provide novel insights into the genetic factors regulating natural variation in

  12. A naturally occurring InDel variation in BraA.FLC.b (BrFLC2 associated with flowering time variation in Brassica rapa

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    Wu Jian

    2012-08-01

    Full Text Available Abstract Background Flowering time is an important trait in Brassica rapa crops. FLOWERING LOCUS C (FLC is a MADS-box transcription factor that acts as a potent repressor of flowering. Expression of FLC is silenced when plants are exposed to low temperature, which activates flowering. There are four copies of FLC in B. rapa. Analyses of different segregating populations have suggested that BraA.FLC.a (BrFLC1 and BraA.FLC.b (BrFLC2 play major roles in controlling flowering time in B. rapa. Results We analyzed the BrFLC2 sequence in nine B. rapa accessions, and identified a 57-bp insertion/deletion (InDel across exon 4 and intron 4 resulting in a non-functional allele. In total, three types of transcripts were identified for this mutated BrFLC2 allele. The InDel was used to develop a PCR-based marker, which was used to screen a collection of 159 B. rapa accessions. The deletion genotype was present only in oil-type B. rapa, including ssp. oleifera and ssp. tricolaris, and not in other subspecies. The deletion genotype was significantly correlated with variation in flowering time. In contrast, the reported splicing site variation in BrFLC1, which also leads to a non-functional locus, was detected but not correlated with variation in flowering time in oil-type B. rapa, although it was correlated with variation in flowering time in vegetable-type B. rapa. Conclusions Our results suggest that the naturally occurring deletion mutation across exon 4 and intron 4 in BrFLC2 gene contributes greatly to variation in flowering time in oil-type B. rapa. The observed different relationship between BrFLC1 or BrFLC2 and flowering time variation indicates that the control of flowering time has evolved separately between oil-type and vegetable-type B. rapa groups.

  13. 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.

  14. Effects of a Changing Climate on Seasonal Variation in Natural Recharge of Unconfined Coastal Aquifers

    Science.gov (United States)

    Antonellini, Marco; Nella Mollema, Pauline

    2013-04-01

    Irregular rainfall patterns throughout the year result in the discontinuous natural recharge of coastal aquifers, which has an effect on the size of freshwater lenses present in sandy deposits. The thickness of the freshwater lenses is important in the context of farmland salinization and coastal ecosystems survival. This study presents numerical models that simulate continuous and discontinuous recharge in sandy coastal aquifers and the thickness of resulting fresh water lenses under current and future climate scenarios. Temperature data for the period 1960-1990 from LOCCLIM FAO and from the IPCC SRES A1b scenario for 2070-2100, have been used to calculate the potential evapotranspiration. Potential recharge was defined as the difference between the precipitation and potential evapotranspiration in twelve locations around the world: Ameland (The Netherlands), Auckland and Wellington (New Zealand), Hong Kong, Ravenna (Italy), Mekong (Vietnam), Mumbai (India), New Jersey (USA), Nile Delta (Egypt), Kobe and Tokyo (Japan), and Singapore. These locations have shallow coastal aquifers along low lying coasts and comparable aquifer structure, which is the result of similar sediment supply and deposition in the Holocene as well as by the sea level changes from the last ice age to the present time. Particular attention has been paid to temporal variations of natural recharge that can vary from continuous recharge throughout the year to discontinuous recharge. The most dramatic reduction in the magnitude of potential annual recharge by the end of this century will occur at lower latitudes (Mumbai, Singapore, Hong Kong and Mekong). The most pronounced change in length of the dry period occurs for Kobe (Japan) and Singapore even though the total annual amount of recharge remains practically the same. The Influence of variable recharge on the size of freshwater lenses surrounded by saline water is simulated with the SEAWAT model. Models where the recharge is applied

  15. Natural variation in early parental care correlates with social behaviors in adolescent prairie voles (Microtus ochrogaster

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    Allison M Perkeybile

    2013-03-01

    Full Text Available Natural variation in early parental care may contribute to long-term changes in behavior in the offspring. Here we investigate the role of variable early care in biparental prairie voles (Microtus ochrogaster. Total amounts of parental care were initially quantified for 24 breeder pairs and pairs were ranked in relation to one another based on total contact. Consistency in key components of care suggested a trait-like quality to parental care. Based on this ranking, breeder pairs from the top (high-contact and bottom (low-contact quartiles were selected to produce high- and low-contact offspring to investigate adolescent behavior after varying early care. Parental care of subject offspring was again observed postnatally. Offspring of high-contact parents spent more time passively nursing and received more paternal nonhuddling contact while low-contact offspring spent more time actively nursing and received more paternal huddling and pseudohuddling in the first postnatal days. Low-contact offspring also displayed faster rates of development on a number of physical markers. Post-weaning, offspring were evaluated on anxiety-like behavior, social behavior and pre-pulse inhibition to a tactile and an acoustic startle. High-contact offspring spent more time sniffing a juvenile and less time autogrooming. With an infant, high-contact offspring spent more time in nonhuddling contact and less time autogrooming and retrieving than did low-contact offspring. Considering sexes separately, high-contact females spent more time sniffing a novel juvenile than low-contact females. High-contact males spent more time in nonhuddling contact with an infant than low-contact males; while low-contact females retrieved infants more than high-contact females. In both measures of social behavior, high-contact males spent less time autogrooming than low-contact males. These results suggest a relationship between early-life care and differences in social behavior in

  16. Unlocking naturally occurring variation for starch quality by gene-tagged markers in rice

    International Nuclear Information System (INIS)

    Quantitative trait loci (QTLs) mapping and association mapping are currently used to dissect the natural occurring variations for traits of agronomical importance. We found that the major QTLs for starch quality co-locate at the starch-synthesizing gene loci, e.g. Wx locus controls the genetic basis of amylose content, pasting viscosity, gel texture and retrogradation properties, while starch synthase IIa (SSIIa) locus controls the gelatinization temperature (GT) and amylopectin structure. Some of other genes involved in starch biosynthesis and other minor QTLs were also detected. Gene tagged markers such as simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) that were inside or close to those starch-synthesizing genes were designed. Among 499 nonwaxy rice accessions, polymorphisms of SSR in the Waxy gene, soluble starch synthase I gene (SS1) and starch branching enzyme I gene (SBE1), SNPs in Waxy and starch branching enzyme III gene (SBE3) and SSIIa, and a sequence tagged site (STS) in SBEI were surveyed. Ten SSR alleles were found at the Wx locus and four SSR alleles were found at the SBE1 and SS1, respectively. Two continuous SNPs (GC/TT) alone can differentiate rice with high or intermediate GT (possessing GC SNPs) from those with low GT (possessing the TT SNPs). Association test was conducted using all starch gene markers, results indicated that Wx SSR and SNPs were strongly associated with amylose content, pasting viscosities, gel hardness, and retrogradation properties, whereas the SSIIa GC/TT SNPs were strongly associated with the pasting temperature and retrogradation properties, which confirmed the findings from QTL mapping. These markers are useful in molecular breeding for improvement of rice eating and cooking qualities. This study was jointly supported by funds from NSFC (30771327), 863 project (2006AA10Z193), Science and Technology Department of Zhejiang Province (2007C32014) and IAEA (12847). (author)

  17. Genetic variation for worm burdens in laying hens naturally infected with gastro-intestinal nematodes.

    Science.gov (United States)

    Wongrak, K; Daş, G; von Borstel, U König; Gauly, M

    2015-01-01

    1. Genetic parameters were determined for the worm burden of the most common gastro-intestinal nematodes in two chicken genotypes after being exposed to free-range farming conditions for a laying period. 2. Seventeen-week-old hens of 2 brown genotypes, Lohmann Brown (LB) plus (n = 230) and LB classic (n = 230), were reared for a laying period and subjected to post-mortem parasitological examinations at 79 weeks (LB plus) or 88 weeks (LB classic) of age. 3. There was no significant difference in faecal egg counts between the genotypes. Almost all hens (>99%) were infected with at least one nematode species. Species-specific nematode prevalence ranged from 85.8% to 99.1% between the two genotypes. Heterakis gallinarum was the most prevalent nematode (98.5%), followed by Ascaridia galli (96.2%) and Capillaria spp. (86.1%). Capillaria spp. were composed of C. obsignata (79%), C. caudinflata (16%) and C. bursata (5%). 4. All phenotypic and genetic correlations among worm counts of different parasite species were positive in combined genotypes (rP ranged from 0.05 to 0.30 and rG ranged from 0.29 to 0.88). A strong genetic correlation (rG = 0.88 ± 0.34) between counts of A. galli and H. gallinarum was quantified. Heritability for total worm burden for LB plus and LB classic, respectively, were 0.55 ± 0.18 and 0.55 ± 0.34. Across both genotypes, the heritability of total worm burden was 0.56 ± 0.16. 5. In conclusion, there is a high variation attributable to genetic background of chickens in their responses to naturally acquired nematode infections. The high positive genetic correlation between counts of closely related worm species (e.g. A. galli and H. gallinarum) may indicate existence of similar genetically determined mechanism(s) in chickens for controlling these nematodes. PMID:25486507

  18. Untangling the nature of spatial variations of cold dust properties in star forming galaxies

    International Nuclear Information System (INIS)

    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 (Tc ) and emissivity (β) on a pixel by pixel basis (where each pixel ranges from 0.1 to 3 kpc2) 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 Tc and β simultaneously, (2) hold β constant and fit Tc . We compare Tc and β with star formation rates (calculated from LHα and L24μm), the luminosity of the old stellar population (traced through L3.6μm), and the dust mass surface density (traced by 500 μm luminosity, L500). We find a significant trend between SFR/L500 and Tc , implying that the flux of hard UV photons relative to the amount of dust is significantly contributing to the heating of the cold, or diffuse, dust component. We also see a trend between L3.6/L500 and β, indicating that the old stellar population contributes to the heating at far-IR/submillimeter wavelengths. Finally, we find that when β is held constant, Tc exhibits a strongly decreasing radial trend, illustrating that the shape of the far-IR SED is changing radially through a galaxy, thus confirming on a sample almost double in size the trends observed in Galametz et al.

  19. Natural variation of heterokaryon incompatibility gene het-c in Podospora anserina reveals diversifying selection.

    Science.gov (United States)

    Bastiaans, Eric; Debets, Alfons J M; Aanen, Duur K; van Diepeningen, Anne D; Saupe, Sven J; Paoletti, Mathieu

    2014-04-01

    In filamentous fungi, allorecognition takes the form of heterokaryon incompatibility, a cell death reaction triggered when genetically distinct hyphae fuse. Heterokaryon incompatibility is controlled by specific loci termed het-loci. In this article, we analyzed the natural variation in one such fungal allorecognition determinant, the het-c heterokaryon incompatibility locus of the filamentous ascomycete Podospora anserina. The het-c locus determines an allogenic incompatibility reaction together with two unlinked loci termed het-d and het-e. Each het-c allele is incompatible with a specific subset of the het-d and het-e alleles. We analyzed variability at the het-c locus in a population of 110 individuals, and in additional isolates from various localities. We identified a total of 11 het-c alleles, which define 7 distinct incompatibility specificity classes in combination with the known het-d and het-e alleles. We found that the het-c allorecognition gene of P. anserina is under diversifying selection. We find a highly unequal allele distribution of het-c in the population, which contrasts with the more balanced distribution of functional groups of het-c based on their allorecognition function. One explanation for the observed het-c diversity in the population is its function in allorecognition. However, alleles that are most efficient in allorecognition are rare. An alternative and not exclusive explanation for the observed diversity is that het-c is involved in pathogen recognition. In Arabidopsis thaliana, a homolog of het-c is a pathogen effector target, supporting this hypothesis. We hypothesize that the het-c diversity in P. anserina results from both its functions in pathogen-defense, and allorecognition. PMID:24448643

  20. Genomic regulation of natural variation in cortical and noncortical brain volume

    Directory of Open Access Journals (Sweden)

    Laughlin Rick E

    2006-02-01

    Full Text Available Abstract Background The relative growth of the neocortex parallels the emergence of complex cognitive functions across species. To determine the regions of the mammalian genome responsible for natural variations in cortical volume, we conducted a complex trait analysis using 34 strains of recombinant inbred (Rl strains of mice (BXD, as well as their two parental strains (C57BL/6J and DBA/2J. We measured both neocortical volume and total brain volume in 155 coronally sectioned mouse brains that were Nissl stained and embedded in celloidin. After correction for shrinkage, the measured cortical and noncortical brain volumes were entered into a multiple regression analysis, which removed the effects of body size and age from the measurements. Marker regression and interval mapping were computed using WebQTL. Results An ANOVA revealed that more than half of the variance of these regressed phenotypes is genetically determined. We then identified the regions of the genome regulating this heritability. We located genomic regions in which a linkage disequilibrium was present using WebQTL as both a mapping engine and genomic database. For neocortex, we found a genome-wide significant quantitative trait locus (QTL on chromosome 11 (marker D11Mit19, as well as a suggestive QTL on chromosome 16 (marker D16Mit100. In contrast, for noncortex the effect of chromosome 11 was markedly reduced, and a significant QTL appeared on chromosome 19 (D19Mit22. Conclusion This classic pattern of double dissociation argues strongly for different genetic factors regulating relative cortical size, as opposed to brain volume more generally. It is likely, however, that the effects of proximal chromosome 11 extend beyond the neocortex strictly defined. An analysis of single nucleotide polymorphisms in these regions indicated that ciliary neurotrophic factor (Cntf is quite possibly the gene underlying the noncortical QTL. Evidence for a candidate gene modulating neocortical

  1. A solar super-flare as cause for the 14C variation in AD 774/5 ?

    CERN Document Server

    Neuhaeuser, Ralph

    2014-01-01

    We present further considerations regarding the strong 14C variation in AD 774/5. For its cause, either a solar super-flare or a short Gamma-Ray Burst were suggested. We show that all kinds of stellar or neutron star flares would be too weak for the observed energy input at Earth in AD 774/5. Even though Maehara et al. (2012) present two super-flares with 10e35 erg of presumably solar-type stars, we would like to caution: These two stars are poorly studied and may well be close binaries, and/or having a M-type dwarf companion, and/or may be much younger and/or much more magnetic than the Sun - in any such case, they might not be true solar analog stars. From the frequency of large stellar flares averaged over all stellar activity phases (maybe obtained only during grand activity maxima), one can derive (a limit of) the probability for a large solar flare at a random time of normal activity: We find the probability for one flare within 3000 years to be possibly as low as 0.3 to 0.008 considering the full 1 sig...

  2. TGFBR3 variation is not a common cause of Marfan-like syndrome and Loeys-Dietz-like syndrome

    Directory of Open Access Journals (Sweden)

    Singh Krishna K

    2012-02-01

    Full Text Available Abstract Marfan syndrome (MFS is caused by mutations in the fibrillin-1 (FBN1 gene, and mutations in FBN1 are known to be responsible for over 90% of all MFS cases. Locus heterogeneity has also been reported and confirmed, with mutations in the receptor genes TGFBR1 and TGFBR2 identified in association with MFS-related phenotypes. It is now known that dysregulation of TGF-ß signaling is involved in MFS pathogenesis. To test the hypothesis that dysregulation of TGFBR3-associated TGF-ß signaling is implicated in MFS or related phenotype pathogenesis, we selected a cohort of 49 patients, fulfilling or nearly fulfilling the diagnostic criteria for MFS. The patients were known not to carry a mutation in the FBN1 gene (including three 5' upstream alternatively spliced exons, the TGFBR1 and TGFBR2 genes. Mutation screening for the TGFBR3 gene in these patients and in controls led to the identification of a total of ten exonic (one novel, four intronic (one novel and one 3'UTR variant in the TGFBR3 gene. Our data suggest that variations in TGFBR3 gene appear not to be associated with MFS or related phenotype.

  3. 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

  4. A High-Definition View of Functional Genetic Variation from Natural Yeast Genomes

    Science.gov (United States)

    Bergström, Anders; Simpson, Jared T.; Salinas, Francisco; Barré, Benjamin; Parts, Leopold; Zia, Amin; Nguyen Ba, Alex N.; Moses, Alan M.; Louis, Edward J.; Mustonen, Ville; Warringer, Jonas; Durbin, Richard; Liti, Gianni

    2014-01-01

    The question of how genetic variation in a population influences phenotypic variation and evolution is of major importance in modern biology. Yet much is still unknown about the relative functional importance of different forms of genome variation and how they are shaped by evolutionary processes. Here we address these questions by population level sequencing of 42 strains from the budding yeast Saccharomyces cerevisiae and its closest relative S. paradoxus. We find that genome content variation, in the form of presence or absence as well as copy number of genetic material, is higher within S. cerevisiae than within S. paradoxus, despite genetic distances as measured in single-nucleotide polymorphisms being vastly smaller within the former species. This genome content variation, as well as loss-of-function variation in the form of premature stop codons and frameshifting indels, is heavily enriched in the subtelomeres, strongly reinforcing the relevance of these regions to functional evolution. Genes affected by these likely functional forms of variation are enriched for functions mediating interaction with the external environment (sugar transport and metabolism, flocculation, metal transport, and metabolism). Our results and analyses provide a comprehensive view of genomic diversity in budding yeast and expose surprising and pronounced differences between the variation within S. cerevisiae and that within S. paradoxus. We also believe that the sequence data and de novo assemblies will constitute a useful resource for further evolutionary and population genomics studies. PMID:24425782

  5. Variation in the flowering time orthologs BrFLC and BrSOC1 in a natural population of Brassica rapa.

    Science.gov (United States)

    Franks, Steven J; Perez-Sweeney, Beatriz; Strahl, Maya; Nowogrodzki, Anna; Weber, Jennifer J; Lalchan, Rebecca; Jordan, Kevin P; Litt, Amy

    2015-01-01

    Understanding the genetic basis of natural phenotypic variation is of great importance, particularly since selection can act on this variation to cause evolution. We examined expression and allelic variation in candidate flowering time loci in Brassica rapa plants derived from a natural population and showing a broad range in the timing of first flowering. The loci of interest were orthologs of the Arabidopsis genes FLC and SOC1 (BrFLC and BrSOC1, respectively), which in Arabidopsis play a central role in the flowering time regulatory network, with FLC repressing and SOC1 promoting flowering. In B. rapa, there are four copies of FLC and three of SOC1. Plants were grown in controlled conditions in the lab. Comparisons were made between plants that flowered the earliest and latest, with the difference in average flowering time between these groups ∼30 days. As expected, we found that total expression of BrSOC1 paralogs was significantly greater in early than in late flowering plants. Paralog-specific primers showed that expression was greater in early flowering plants in the BrSOC1 paralogs Br004928, Br00393 and Br009324, although the difference was not significant in Br009324. Thus expression of at least 2 of the 3 BrSOC1 orthologs is consistent with their predicted role in flowering time in this natural population. Sequences of the promoter regions of the BrSOC1 orthologs were variable, but there was no association between allelic variation at these loci and flowering time variation. For the BrFLC orthologs, expression varied over time, but did not differ between the early and late flowering plants. The coding regions, promoter regions and introns of these genes were generally invariant. Thus the BrFLC orthologs do not appear to influence flowering time in this population. Overall, the results suggest that even for a trait like flowering time that is controlled by a very well described genetic regulatory network, understanding the underlying genetic basis of

  6. 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…

  7. Bacterial Community in Natural Grassland of Uruguay: Assessment of Effects caused by Cattle Grazing

    International Nuclear Information System (INIS)

    The Campos in Uruguay, the Pampa in Argentina and southern Brazil comprise one of the largest areas of natural temperate sub-humid grasslands. In Uruguay 87% of the country is occupied by natural grasslands grazed by domestic herbivores, mainly cattle and sheep. Grazing is a key disturbance that shapes grassland communities, drastically altering plant species composition. (Author)

  8. The criteria of natural disasters, caused by hydro-meteorological natural phenomena in winter period in different urban regions of Russia

    Science.gov (United States)

    Gavrilova, S.

    2012-04-01

    Russia is one of the most spread countries in the world and it has the big number of different types of natural phenomena, which can cause natural disaster. Unfortunately, nowadays the number of victims of natural hazards and their influence on technological systems doesn't decrease. There are many reasons of that situation - both geographical and human. One of the reasons is the fact that the criteria of which meteorological or hydrological conditions can cause an emergency situation are equal for the whole territory of Russia. And that's why many dangerous situations are underestimated. The analysis of the distribution of criteria in Russia shows that only temperature phenomena (such as frost or heat) have really space differentiation. The criteria of different natural disasters and hazards should depend on many factors - both social-economical and hydro-meteorological. Social-economical factors depend on human occupancy of territory, on the method of usage the land etc. So, it is clear, that in very populated areas (as big cities) the criteria should be different than in other areas. Hydro-meteorological factors deal with climatic and landscape conditions of the territories. The geographical zoning of Russia was conduct and clusters with equal parameters were determined. That means that in these areas the same hydro meteorological characteristics can be used for. The new criteria for the number of natural phenomena (such as hale, snowfalls etc) were found. The updated criteria was determined both by analyzing the factual reports on emergency situation, caused by natural phenomena in each cluster and the characteristics from meteorological stations. Updating criteria of natural disasters, taking into account different characteristics of the analyzing area can be wildly used in Russian ministry of emergency situation and Gydrometeorological services for predicting emergency situation for safety and sustainable development in different regions.* *The work was

  9. Variation in Risk Seeking Behavior in a Natural Experiment on Large Losses Induced by a Natural Disaster

    OpenAIRE

    Page, Lionel; Savage, David; Torgler, Benno

    2012-01-01

    This study explores people's risk attitudes after having suffered large real-world losses following a natural disaster. Using the margins of the 2011 Australian floods (Brisbane) as a natural experimental setting, we find that homeowners who were victims of the floods and face large losses in property values are 50% more likely to opt for a risky gamble - a scratch card giving a small chance of a large gain ($ 500,000) - than for a sure amount of comparable value ($ 10). This finding is consi...

  10. Utilization of natural variations in the abundance of nitrogen-15 as a tracer in hydrogeology - Initial results

    International Nuclear Information System (INIS)

    Nitrogen compounds dissolved in natural waters exhibit considerable variations in nitrogen-15 content (more than 10 per mille). The authors describe briefly the analytical techniques used in measuring δ15N, the main features of the isotopic cycle of nitrogen and the results obtained so far. A simplified model of the nitrogen cycle and its isotopic implications is presented; with this model one can deduce from a number of observed variations the physical or biological mechanism (or mechanisms) involved. Isotopic studies of nitrogen may be a useful additional tool for detecting and interpreting certain forms of pollution. (author)

  11. Impacts of decadal variations in natural emissions due to land-cover changes on ozone production in southern China

    Directory of Open Access Journals (Sweden)

    Mengmeng Li

    2015-09-01

    Full Text Available The decadal variations in emissions of high-reactivity biogenic volatile organics (BVOCs, as a result of land-cover changes, could significantly impact ozone (O3 production. In this study, the Weather Research and Forecasting/Chemistry (WRF/Chem modelling system, coupled with dynamic vegetation data sets derived from Moderate Resolution Imaging Spectroradiometer (MODIS, 2001–2012 and Advanced Very High Resolution Radiometer (AVHRR, early 1990s measurements, were used to investigate the impacts of land-cover changes on natural emissions, and consequently O3 production, in the Pearl River Delta (PRD region of southern China over the past two decades. Model results indicate that BVOC emissions were highly dependent on forest area. The total BVOC emissions in the modelling domain increased by a factor of two due to afforestation since the early 1990s, declined slowly (−5.8% yr−1 until 2006 and then increased continuously (+9.1% yr−1 to 2012. The decadal variations in BVOC emissions have complex implications for summer O3 production in PRD, depending on the chemical regimes and prevailing winds. The impacts on O3 production were most sensitive in downwind areas, and it was found that the large increase in BVOC emissions during 2006–2012 tended to reduce surface O3 concentrations by 1.6–2.5 ppb in rural regions, but caused an increment of O3 peaks by up to 2.0–6.0 ppb in VOC-limited urban areas (e.g., Guangzhou, Foshan and Zhongshan. The opposite was true in the period 2001–2006, when the reduced BVOC emissions resulted in 1.3–4.0 ppb increases in daytime O3 concentrations over northern rural regions. Impact of the two-fold increase in BVOC emissions since the early 1990s to 2006 was a 0.9–4.6 ppb increment in surface O3 concentrations over the downwind areas. This study suggests that the potential impacts on ozone chemistry should be considered in long-term land-use planning and air-quality management.

  12. 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 birt...

  13. 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.

  14. Genetic basis for spontaneous hybrid genome doubling during allopolyploid speciation of common wheat shown by natural variation analyses of the paternal species.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Matsuoka

    Full Text Available The complex process of allopolyploid speciation includes various mechanisms ranging from species crosses and hybrid genome doubling to genome alterations and the establishment of new allopolyploids as persisting natural entities. Currently, little is known about the genetic mechanisms that underlie hybrid genome doubling, despite the fact that natural allopolyploid formation is highly dependent on this phenomenon. We examined the genetic basis for the spontaneous genome doubling of triploid F1 hybrids between the direct ancestors of allohexaploid common wheat (Triticum aestivum L., AABBDD genome, namely Triticumturgidum L. (AABB genome and Aegilopstauschii Coss. (DD genome. An Ae. tauschii intraspecific lineage that is closely related to the D genome of common wheat was identified by population-based analysis. Two representative accessions, one that produces a high-genome-doubling-frequency hybrid when crossed with a T. turgidum cultivar and the other that produces a low-genome-doubling-frequency hybrid with the same cultivar, were chosen from that lineage for further analyses. A series of investigations including fertility analysis, immunostaining, and quantitative trait locus (QTL analysis showed that (1 production of functional unreduced gametes through nonreductional meiosis is an early step key to successful hybrid genome doubling, (2 first division restitution is one of the cytological mechanisms that cause meiotic nonreduction during the production of functional male unreduced gametes, and (3 six QTLs in the Ae. tauschii genome, most of which likely regulate nonreductional meiosis and its subsequent gamete production processes, are involved in hybrid genome doubling. Interlineage comparisons of Ae. tauschii's ability to cause hybrid genome doubling suggested an evolutionary model for the natural variation pattern of the trait in which non-deleterious mutations in six QTLs may have important roles. The findings of this study demonstrated

  15. Untangling the nature of spatial variations of cold dust properties in star forming galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Kirkpatrick, Allison; Calzetti, Daniela [Department of Astronomy, University of Massachusetts, Amherst, MA 01002 (United States); Kennicutt, Robert [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Galametz, Maud [European Southern Observatory, Karl-Schwarzchild-Str. 2, D-85748 Garching-bei-München (Germany); Gordon, Karl [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Groves, Brent; Tabatabaei, Fatemeh [Max-Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); Hunt, Leslie [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Dale, Daniel [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Hinz, Joannah, E-mail: kirkpatr@astro.umass.edu [MMT Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States)

    2014-07-10

    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{sub c} ) and emissivity (β) on a pixel by pixel basis (where each pixel ranges from 0.1 to 3 kpc{sup 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{sub c} and β simultaneously, (2) hold β constant and fit T{sub c} . We compare T{sub c} and β with star formation rates (calculated from L{sub Hα} and L{sub 24μm}), the luminosity of the old stellar population (traced through L{sub 3.6μm}), and the dust mass surface density (traced by 500 μm luminosity, L{sub 500}). We find a significant trend between SFR/L{sub 500} and T{sub c} , implying that the flux of hard UV photons relative to the amount of dust is significantly contributing to the heating of the cold, or diffuse, dust component. We also see a trend between L{sub 3.6}/L{sub 500} and β, indicating that the old stellar population contributes to the heating at far-IR/submillimeter wavelengths. Finally, we find that when β is held constant, T{sub c} exhibits a strongly decreasing radial trend, illustrating that the shape of the far-IR SED is changing radially through a galaxy, thus confirming on a sample almost double in size the trends observed in Galametz et al.

  16. Suppression scheme of COD variation caused by switching ripple in J-PARC 3GeV dipole magnet power supply

    International Nuclear Information System (INIS)

    In J-PARC RCS, horizontal closed orbit distortion (COD) which is ±2 or 3mm in amplitude was observed all over the ring. Main component of the horizontal COD is 1kHz, phase variation period is about 140 seconds. This paper demonstrates phase variation of the 1kHz horizontal COD caused by switching ripple from dipole magnet power supply. To suppress the phase variation of the horizontal COD, switching timing of the dipole magnet power supply was synchronized J-PARC timing system. (author)

  17. On the meaning of the special-cause variation concept used in the quality discourse – And its link to unforeseen and surprising events in risk management

    International Nuclear Information System (INIS)

    In quality management, ‘common-cause variation’ and ‘special-cause variation’ are key concepts used to control and improve different types of processes. In this paper we study the meaning of these concepts, having a special focus on the latter concept: how is the special-cause concept linked to ideas and concepts used in risk and uncertainty management, to reflect unforeseen and surprising events? In the quality discourse it is common to refer to two possible mistakes when confronting the variation: (i) to react to an outcome as if it were from a special cause, when actually it came from common causes of variation; and (ii) to treat an outcome as if it were from common causes of variation, when actually it came from a special cause. However, at the point of decision making it is difficult or impossible to know what the “true” state is. It is also appropriate to ask whether such a true state does in fact exist. In the paper we discuss these issues, the main aim of the paper being to improve our understanding of some of the fundamental concepts used in risk and quality management

  18. Genetic variations in marine natural population - Measurement and utility in resource management and conservation: A review

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.; Parulekar, A.H.

    A number of molecular and biochemical tools which can be applied to the identification of species and the detection of genetic variation within species have been developed in recent years. All these methods rely on the ability to distinguish between...

  19. 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.

  20. 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,…

  1. 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).

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

    OpenAIRE

    Fernandez-Gonzalez, Victoria; Aguado Giménez, Felipe; Gairin Deulofeu, Joan Ignasi; Sanchez-Jerez, Pablo

    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 ...

  3. Postponed reproduction as an adaptation to winter conditions in Drosophila melanogaster: evidence for clinal variation under semi-natural conditions.

    OpenAIRE

    Mitrovski, P.; Hoffmann, A. A.

    2001-01-01

    Patterns of climatic adaptation in drosophila and other insects have largely been inferred from laboratory comparisons of traits that vary clinally. Here, we extend this research to comparisons under semi-natural conditions. To test for clinal variation in reproductive patterns and survival over winter, Drosophila melanogaster populations were initiated from seven collection sites along the eastern coast of Australia, ranging from tropical to temperate regions. The fecundity and survival of t...

  4. 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

  5. Extreme values in the water rivers flow evolution, caused by extreme variations of precipitation, water frost or karst

    International Nuclear Information System (INIS)

    In this work, there are presented special situations occurred in the evolution of the water rivers flow, caused by different factors: extreme variations of precipitation, important volumes of ice stored in thick ice layers, raising of large levels determined by the presence of the ice jams, infiltrations, strong exsurgence from the karstic area. For every situation are presented concrete examples met on some rivers of Romania. The studies led to the specification of the factors that determined these extreme situations. This specification was made quantitatively on the basis of the relations established between these extreme values of the flow and the characteristics of the factors that determined them. Thus, in the case of small rivers from the eastern part of Romania, with areas till 15-20 km2 is presented first the flow regime, characterized through long periods of drought, over 100-50 days per year, on which there are overlapped rare but very strong floods. There are also presented situations when in melt snow periods, of only 10-15 days, are realised water volumes, which represent 70-75% of the annual stock of the flow. This is the direct effect of the excessive continental climate specific to this area. The analysis was materialized through the establishment of the dependence of drought phenomenon moment and duration to the precipitation quantity, taking into consideration the soil humidity before the drought phenomenon occurrence. The characteristics of the maximum flow were determined on the basis of precipitation characteristics in the context of their torrential regime, especially in the framework of small hydrographic basins conditions. For illustrating the remarkable diminishing of the water discharge due to the freezing on some rivers from Transylvania and Northern Moldavia, there were first established the sectors the most affected by the frost. In this purpose, there were obtained relations between the maximum thickness of the ice layers and the

  6. 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; Kuehn, A; Grunow, R; Blixt, Klas Ola; Bovin, N V

    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...

  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. 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

  9. The nature of anterior negativities caused by misapplications of morphological rules

    NARCIS (Netherlands)

    Krott, A.; Baayen, R.H.; Hagoort, P.

    2006-01-01

    This study investigates functional interpretations of left anterior negativities (LANs), a language-related electroencephalogram effect that has been found for syntactic and morphological violations. We focus on three possible interpretations of LANs caused by the replacement of irregular affixes wi

  10. Assessing genetic variation in natural populations of the New World screwworm fly, Cochliomyia hominivorax

    International Nuclear Information System (INIS)

    Full text: Through participation in the FAO/IAEA coordinated research project 'Enabling Technologies for the Expansion of SIT for Old and New World Screwworm Fly', we have been able to analyse samples of New World screwworm fly from across the range of this insect pest. This presentation will bring together data from a range of genetic markers that have been used to assess levels of genetic variation within populations of the New World screwworm fly, Cochliomyia hominivorax. The markers used include: rRNA gene sequences, together with sequence information from protein coding genes, and microsatellites, allowing variation to be assessed at a range of levels from species to population. (author)

  11. Mathematical modeling of growth processes in nature and engineering: A variational approach

    Energy Technology Data Exchange (ETDEWEB)

    Manzhirov, A V; Lychev, S A, E-mail: manzh@ipmnet.r [Ishlinsky Institute for Problems in Mechanics of the Russian Academy of Sciences, Vernadsky Ave 101 Bldg 1, Moscow, 119526 (Russian Federation)

    2009-08-01

    We present a variational approach to the mathematical theory of accreted solids. One main point in this approach is that the operator of the accretion problem proves to be self-adjoint with respect to an appropriately modified convolution bilinear form, and it is this linear form that we use in the construction of the variational functional. Our growing solid model can be efficiently applied to describe processes such as concreting, pyrolytic deposition, laser spraying, electrolytic deposition, polymerization, solidification of melts, crystal growth, glacier and ice cover freezing, sedimentary and volcanic rock forming, and biological tissue growth. These applications will be considered elsewhere.

  12. Development of the information subsystem for monitoring pollution of natural healing resources caused by road transport

    OpenAIRE

    Мещеряков, Владимир Иванович; Гнатовская, Анна Арнольдовна; Черепанова, Екатерина Валерьевна; Фоменко, Виталий Викторович

    2014-01-01

    Natural healing resources (mud, mineral water, etc.) are affected by man-made pollution, such as road transport, therefore, require monitoring of their condition and taking protective measures to mitigate these impacts. Implementation of the task is impossible without creating an information system for monitoring and subsequent analysis of the impact of polluting factors on changes in biochemical composition of healing resources. Concerning necessary functions, this information tool should pr...

  13. Most common causes of natural and injury-related deaths in Addis Ababa, Ethiopia

    OpenAIRE

    Gemechu, Tufa; Tinsae, Mihrete; Ashenafi, Senait; Rodriguez, Victor Manuel; Lori, Alfredo; Collins, Michelle; Hurford, Rosemary; Haimanot, Rahel; Sandoval, Melissa; Mehari, Enawgaw; Langford, T. Dianne

    2009-01-01

    In Ethopia, like many developing countries, autopsy is rare unless conducted in the medico-legal arena, making vital statistics that include sparse pathological diagnoses. To determine the most common factors contributing to death among individuals who died from natural or injury-related events in Ethiopia in 2006, 200 consecutive autopsies were conducted at the Forensic Medico-legal Pathology Department, Menelik II Hospital, Addis Ababa, Ethiopia. The results describe significant pathologica...

  14. Natural disasters in Lake Victoria Basin (Kenya): Causes and impacts on environment and livelihoods.

    OpenAIRE

    Opere, A.; Ogallo, L.A.

    2006-01-01

    The paper puts into context, the main forms of natural disastors that predisposes the environment and inhabitants of the Lake Victoria basin to vulnerabilities. Singling out drought and floods as the most devastating natyral harzards, the paper presents a conceivable drivers of the the two phenomena, their social, economic and environmental consequences as well as opportunities for prevention, mitigation and management The social and biophysical characteristics that increase vulnerabilities t...

  15. Methods for predicting peak discharge of floods caused by failure of natural and constructed earthen dams

    Science.gov (United States)

    Walder, J.S.; O'Connor, J. E.

    1997-01-01

    Floods from failures of natural and constructed dams constitute a widespread hazard to people and property. Expeditious means of assessing flood hazards are necessary, particularly in the case of natural dams, which may form suddenly and unexpectedly. We revise statistical relations (derived from data for past constructed and natural dam failures) between peak discharge (Q(p)) and water volume released (V(0)) or drop in lake level (d) but assert that such relations, even when cast into a dimensionless form, are of limited utility because they fail to portray the effect of breach-formation rate. We then analyze a simple, physically based model of dam-breach formation to show that the hydrograph at the breach depends primarily on a dimensionless parameter ?? = kV0/g1/2d7/2, where k is the mean erosion rate of the breach and g is acceleration due to gravity. The functional relationship between Q(p) and ?? takes asymptotically distinct forms depending on whether ?? > 1 (relatively fast breach formation or large lake volume). Theoretical predictions agree well with data from dam failures for which k, and thus ??, can be estimated. The theory thus provides a rapid means of predicting the plausible range of values of peak discharge at the breach in an earthen dam as long as the impounded water volume and the water depth at the dam face can be estimated.

  16. Patterned Ground in Wetlands of the Maya Lowlands: Anthropogenic and Natural Causes

    Science.gov (United States)

    Beach, T.; Beach, S. L.

    2004-12-01

    We use geological and archaeological evidence to understand the formation of patterned ground in perennial and seasonal wetlands in the karst depressions of Belize and Guatemala. Some scholars have argued that these features are the remnants of ancient Maya wetland fields, chinampas, on which intensive cultivation produced food that could begin to nourish the extremely high population of the Late Classic (A.D. 550-850). Others have argued that these were natural features or that they represent landscape manipulation for rising sea level in the Preclassic (1000 B.C. -A.D. 250). We present the evidence for ancient intensive agriculture and natural landscape formation with multiple proxies: excavated field and canal features, artifacts, pollen, soil stratigraphy, and water chemistry. Evidence thus far suggests that many regional depressions have Preclassic (1200 BC to AD 200) or earlier paleosols, buried from 1-2 m by eroded soils induced by Maya land use practices. These paleosols were buried by eroded sediments from uplands and by precipitation of gypsum from rising groundwater. The sedimentation occurred largely between the Preclassic and Late Classic, when ancient Maya farmers built canals in pre-existing low spots to reclaim these wetlands. Thus, stable natural processes, environmental change, and human manipulation have acted together to form patterned wetland ground over the later Holocene.

  17. Natural Selection and Evolution: Using Multimedia Slide Shows to Emphasize the Role of Genetic Variation

    Science.gov (United States)

    Malone, Molly

    2012-01-01

    Most middle school students comprehend that organisms have adaptations that enable their survival and that successful adaptations prevail in a population over time. Yet they often miss that those bird beaks, moth-wing colors, or whatever traits are the result of random, normal genetic variations that just happen to confer a negative, neutral, or…

  18. 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...

  19. Assessment of the natural variation of low abundant metabolic proteins in soybean seeds using proteomics

    Science.gov (United States)

    Using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry, we investigated the distribution of the low abundant proteins that are involved in soybean seed development in four wild and twelve cultivated soybean genotypes. We found proteomic variation of these proteins within and...

  20. 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.

  1. 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…

  2. The nature of anterior negativities caused by misapplications of morphological rules

    OpenAIRE

    Krott, A.; Baayen, R.H.; Hagoort, P.

    2006-01-01

    This study investigates functional interpretations of left anterior negativities (LANs), a language-related electroencephalogram effect that has been found for syntactic and morphological violations. We focus on three possible interpretations of LANs caused by the replacement of irregular affixes with regular affixes: misapplication of morphological rules, mismatch of the presented form with analogy-based expectations, and mismatch of the presented form with stored representations. Event-rela...

  3. The Diffusion of Employment Flexibility in Nigeria’s Banking Industry: Its Nature, Extent and Causes

    Directory of Open Access Journals (Sweden)

    Ifedapo Adeleye

    2011-04-01

    Full Text Available The increasing globalization of the world economy in recent years has triggered debates on whether and to whatextent organizations in non-Western countries will embrace Western-style HRM practices. In particular, the issueof employment flexibility has received considerable attention. This paper explores the level of diffusion ofemployment flexibility in the Nigerian banking industry, analyzing whether the organization of employment inthe three locally-owned case study organizations is becoming more or less flexible, why and how. The resultsfrom this study indicate that there are different levels of diffusion of employment flexibility across the banks, withdifferent patterns as well in the types of jobs with atypical employment contracts. These variations can beexplained by differences in the strategic priorities of each of the firms, as well as the uneven impact of powerfulpressures exerted by various institutional actors.

  4. Navigating natural variation in herbivory-induced secondary metabolism in coyote tobacco populations using MS/MS structural analysis.

    Science.gov (United States)

    Li, Dapeng; Baldwin, Ian T; Gaquerel, Emmanuel

    2015-07-28

    Natural variation can be extremely useful in unraveling the determinants of phenotypic trait evolution but has rarely been analyzed with unbiased metabolic profiling to understand how its effects are organized at the level of biochemical pathways. Native populations of Nicotiana attenuata, a wild tobacco species, have been shown to be highly genetically diverse for traits important for their interactions with insects. To resolve the chemodiversity existing in these populations, we developed a metabolomics and computational pipeline to annotate leaf metabolic responses to Manduca sexta herbivory. We selected seeds from 43 accessions of different populations from the southwestern United States--including the well-characterized Utah 30th generation inbred accession--and grew 183 plants in the glasshouse for standardized herbivory elicitation. Metabolic profiles were generated from elicited leaves of each plant using a high-throughput ultra HPLC (UHPLC)-quadrupole TOFMS (qTOFMS) method, processed to systematically infer covariation patterns among biochemically related metabolites, as well as unknown ones, and finally assembled to map natural variation. Navigating this map revealed metabolic branch-specific variations that surprisingly only partly overlapped with jasmonate accumulation polymorphisms and deviated from canonical jasmonate signaling. Fragmentation analysis via indiscriminant tandem mass spectrometry (idMS/MS) was conducted with 10 accessions that spanned a large proportion of the variance found in the complete accession dataset, and compound spectra were computationally assembled into spectral similarity networks. The biological information captured by this networking approach facilitates the mining of the mass spectral data of unknowns with high natural variation, as demonstrated by the annotation of a strongly herbivory-inducible phenolic derivative, and can guide pathway analysis. PMID:26170304

  5. 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.

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

    OpenAIRE

    Wilhelm Larry J; Tripp H James; Givan Scott A; Smith Daniel P; Giovannoni Stephen J

    2007-01-01

    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...

  7. Naturally Occurring Variations in the Human Cholinesterase Genes: Heritability and Association with Cardiovascular and Metabolic Traits

    OpenAIRE

    Valle, Anne M.; Radić, Zoran; Rana, Brinda K.; Mahboubi, Vafa; Wessel, Jennifer; Shih, Pei-an Betty; Rao, Fangwen; O'Connor, Daniel T.; Taylor, Palmer

    2011-01-01

    Cholinergic neurotransmission in the central and autonomic nervous systems regulates immediate variations in and longer-term maintenance of cardiovascular function with acetylcholinesterase (AChE) activity that is critical to temporal responsiveness. Butyrylcholinesterase (BChE), largely confined to the liver and plasma, subserves metabolic functions. AChE and BChE are found in hematopoietic cells and plasma, enabling one to correlate enzyme levels in whole blood with hereditary traits in twi...

  8. Analysis of two single trait loci affecting flavonol glycoside accumulations in Arabidopsis thaliana natural variations

    OpenAIRE

    Ishihara, Hirofumi

    2007-01-01

    Various plant secondary metabolites, including flavonoids, are involved in plant adaptation to different environments. The needs of sessile lifestyle of plants may have increased the variation of enzymes which are required in the modification and/or accumulation of different flavonol derivatives. The probable mechanism for generating variants of the enzymes is by mutating the corresponding genes. Therefore, Arabidopsis thaliana wildtype accessions collected from different environments and loc...

  9. 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.

  10. Variation in Chemical Defense Among Natural Populations of Common Toad, Bufo bufo, Tadpoles: the Role of Environmental Factors.

    Science.gov (United States)

    Bókony, Veronika; Móricz, Ágnes M; Tóth, Zsófia; Gál, Zoltán; Kurali, Anikó; Mikó, Zsanett; Pásztor, Katalin; Szederkényi, Márk; Tóth, Zoltán; Ujszegi, János; Üveges, Bálint; Krüzselyi, Dániel; Capon, Robert J; Hoi, Herbert; Hettyey, Attila

    2016-04-01

    Defensive toxins are widespread in nature, yet we know little about how various environmental factors shape the evolution of chemical defense, especially in vertebrates. In this study we investigated the natural variation in the amount and composition of bufadienolide toxins, and the relative importance of ecological factors in predicting that variation, in larvae of the common toad, Bufo bufo, an amphibian that produces toxins de novo. We found that tadpoles' toxin content varied markedly among populations, and the number of compounds per tadpole also differed between two geographical regions. The most consistent predictor of toxicity was the strength of competition, indicating that tadpoles produced more compounds and larger amounts of toxins when coexisting with more competitors. Additionally, tadpoles tended to contain larger concentrations of bufadienolides in ponds that were less prone to desiccation, suggesting that the costs of toxin production can only be afforded by tadpoles that do not need to drastically speed up their development. Interestingly, this trade-off was not alleviated by higher food abundance, as periphyton biomass had negligible effect on chemical defense. Even more surprisingly, we found no evidence that higher predation risk enhances chemical defenses, suggesting that low predictability of predation risk and high mortality cost of low toxicity might select for constitutive expression of chemical defense irrespective of the actual level of predation risk. Our findings highlight that the variation in chemical defense may be influenced by environmental heterogeneity in both the need for, and constraints on, toxicity as predicted by optimal defense theory. PMID:27059330

  11. 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.

  12. 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.

  13. 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.

  14. Destructive Interactions Between Mitigation Strategies and the Causes of Unexpected Failures in Natural Hazard Mitigation Systems

    Science.gov (United States)

    Day, S. J.; Fearnley, C. J.

    2013-12-01

    Large investments in the mitigation of natural hazards, using a variety of technology-based mitigation strategies, have proven to be surprisingly ineffective in some recent natural disasters. These failures reveal a need for a systematic classification of mitigation strategies; an understanding of the scientific uncertainties that affect the effectiveness of such strategies; and an understanding of how the different types of strategy within an overall mitigation system interact destructively to reduce the effectiveness of the overall mitigation system. We classify mitigation strategies into permanent, responsive and anticipatory. Permanent mitigation strategies such as flood and tsunami defenses or land use restrictions, are both costly and 'brittle': when they malfunction they can increase mortality. Such strategies critically depend on the accuracy of the estimates of expected hazard intensity in the hazard assessments that underpin their design. Responsive mitigation strategies such as tsunami and lahar warning systems rely on capacities to detect and quantify the hazard source events and to transmit warnings fast enough to enable at risk populations to decide and act effectively. Self-warning and voluntary evacuation is also usually a responsive mitigation strategy. Uncertainty in the nature and magnitude of the detected hazard source event is often the key scientific obstacle to responsive mitigation; public understanding of both the hazard and the warnings, to enable decision making, can also be a critical obstacle. Anticipatory mitigation strategies use interpretation of precursors to hazard source events and are used widely in mitigation of volcanic hazards. Their critical limitations are due to uncertainties in time, space and magnitude relationships between precursors and hazard events. Examples of destructive interaction between different mitigation strategies are provided by the Tohoku 2011 earthquake and tsunami; recent earthquakes that have impacted

  15. Genome-wide association analyses reveal complex genetic architecture underlying natural variation for flowering time in canola.

    Science.gov (United States)

    Raman, H; Raman, R; Coombes, N; Song, J; Prangnell, R; Bandaranayake, C; Tahira, R; Sundaramoorthi, V; Killian, A; Meng, J; Dennis, E S; Balasubramanian, S

    2016-06-01

    Optimum flowering time is the key to maximize canola production in order to meet global demand of vegetable oil, biodiesel and canola-meal. We reveal extensive variation in flowering time across diverse genotypes of canola under field, glasshouse and controlled environmental conditions. We conduct a genome-wide association study and identify 69 single nucleotide polymorphism (SNP) markers associated with flowering time, which are repeatedly detected across experiments. Several associated SNPs occur in clusters across the canola genome; seven of them were detected within 20 Kb regions of a priori candidate genes; FLOWERING LOCUS T, FRUITFUL, FLOWERING LOCUS C, CONSTANS, FRIGIDA, PHYTOCHROME B and an additional five SNPs were localized within 14 Kb of a previously identified quantitative trait loci for flowering time. Expression analyses showed that among FLC paralogs, BnFLC.A2 accounts for ~23% of natural variation in diverse accessions. Genome-wide association analysis for FLC expression levels mapped not only BnFLC.C2 but also other loci that contribute to variation in FLC expression. In addition to revealing the complex genetic architecture of flowering time variation, we demonstrate that the identified SNPs can be modelled to predict flowering time in diverse canola germplasm accurately and hence are suitable for genomic selection of adaptative traits in canola improvement programmes. PMID:26428711

  16. 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

    2014-01-01

    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. PMID:25553069

  17. Contamination of settling ponds of coal mines caused by natural radionuclides

    International Nuclear Information System (INIS)

    As a result of a discharge of the radium-bearing waters from coal mines into settlement ponds and later into rivers a significant increase of radium concentration in bottom sediments can be observed. Sometimes also a contamination of river banks, soils and vegetation occurs. Mine waters contain mainly radium isotopes i.e. 226Ra from uranium series and 228Ra from thorium series. Due to chemical properties of such brines, these waters contain usually no uranium, no thorium and rather seldom elevated concentration of other isotopes as lead (210Pb) and polonium (210Po). The deposition or adsorption of radium on bottom sediments may take place on a distance of several kilometers from the discharge points. After a deposition or adsorption of radium isotopes the built-up of the activity of their progeny begins. Therefore concentrations of radium isotopes are higher than the decay products. We are able to measure the disequilibrium in 226Ra decay chain as well as in 228Ra decay chain, which shows the approximate age of the deposit. The paper describes results of investigation of sediments with enhanced natural radioactivity occurring in settlement ponds, where mine waters have been dumped. The results of measurements show that these deposits contain mainly 226Ra and 228Ra and their progeny. Influence of bottom sediments with enhanced radium concentration on the natural environment in the vicinity of settlement ponds was studied on the example of two different water reservoirs where radium-bearing mine waters type A and B are released. The results show clearly enhanced radioactivity of bottom sediments and water in the settling ponds and in the rivers, but no evident enhancement was found in the adjacent land. Both coal mines are located in the drainage area of Vistula river, and bottom sediments with enhanced radium concentrations were found in Vistula up to 70 km downstream from the discharge point. (author)

  18. 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…

  19. 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...... polyphemus, which has the largest climatic differences between different populations. Local adaptation driven by sexual selection was expected in males but not females because horseshoe crab mating behaviour leads to competition between males, but not between females. Three hundred fifty-nine horseshoe crabs...

  20. Variation in risk seeking behavior following large losses: A natural experiment

    OpenAIRE

    Lionel Page; David A Savage; Benno Torgler

    2013-01-01

    This study explores people's risk attitudes after having suff ered large real-world losses following a natural disaster. Using the margins of the 2011 Australian floods (Brisbane) as a natural experimental setting, we find that homeowners who were victims of the floods and face large losses in property values are 50% more likely to opt for a risky gamble { a scratch card giving a small chance of a large gain ($500,000) { than for a sure amount of comparable value ($10). This finding is consis...

  1. 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...... to be affected by eQTLs as protein-coding RNAs. We identified a genetic variation of swc5 that modifies the levels of 871 RNAs, with effects on both sense and antisense transcription, and show that this effect most likely goes through a compromised deposition of the histone variant H2A.Z. The strains, methods......, and datasets generated here provide a rich resource for future studies....

  2. The Nature of Genetic Variation for Complex Traits Revealed by GWAS and Regional Heritability Mapping Analyses.

    Science.gov (United States)

    Caballero, Armando; Tenesa, Albert; Keightley, Peter D

    2015-12-01

    We use computer simulations to investigate the amount of genetic variation for complex traits that can be revealed by single-SNP genome-wide association studies (GWAS) or regional heritability mapping (RHM) analyses based on full genome sequence data or SNP chips. We model a large population subject to mutation, recombination, selection, and drift, assuming a pleiotropic model of mutations sampled from a bivariate distribution of effects of mutations on a quantitative trait and fitness. The pleiotropic model investigated, in contrast to previous models, implies that common mutations of large effect are responsible for most of the genetic variation for quantitative traits, except when the trait is fitness itself. We show that GWAS applied to the full sequence increases the number of QTL detected by as much as 50% compared to the number found with SNP chips but only modestly increases the amount of additive genetic variance explained. Even with full sequence data, the total amount of additive variance explained is generally below 50%. Using RHM on the full sequence data, a slightly larger number of QTL are detected than by GWAS if the same probability threshold is assumed, but these QTL explain a slightly smaller amount of genetic variance. Our results also suggest that most of the missing heritability is due to the inability to detect variants of moderate effect (∼0.03-0.3 phenotypic SDs) segregating at substantial frequencies. Very rare variants, which are more difficult to detect by GWAS, are expected to contribute little genetic variation, so their eventual detection is less relevant for resolving the missing heritability problem. PMID:26482794

  3. Natural variation of submergence tolerance among Arabidopsis thaliana accessions

    DEFF Research Database (Denmark)

    Vashisht, D.; Hesselink, A.; Pierik, R.; Ammerlaan, J.M.H.; Bailey-Serres, J.; Visser, E.J.W.; Pedersen, Ole; van Zanten, M.; Vreugdenhil, D.; Jamar, D.C.L.; Voesenek, L.A.C.J.; Sasidharan, R.

    2011-01-01

    the dark. Survival curves were plotted to estimate median lethal times as a measure of tolerance. Flooding-associated survival parameters, such as root and shoot oxygen content, initial carbohydrate content and petiole elongation under water, were also measured. • There was a significant variation in...... submergence tolerance among Arabidopsis accessions. However, the order of tolerance did not correlate with root and shoot oxygen content or initial amounts of shoot starch and total soluble sugars. A negative correlation was observed between submergence tolerance and underwater petiole elongation...

  4. Variation in cardiac glycoside content of monarch butterflies from natural populations in eastern North America.

    Science.gov (United States)

    Brower, L P; McEvoy, P B; Williamson, K L; Flannery, M A

    1972-08-01

    A new spectrophotometric assay has been used to determine the gross concentration of cardiac glycoside in individual monarch butterflies. Adults sampled during the fall migration in four areas of eastern North America exhibited a wide variation in cardiac glycoside concentration. The correlation between spectrophotometrically measured concentrations and emetic dose determinations supports the existence of a broad palatability spectrum in wild monarch butterflies. The cardiac gylcoside concentration is greater in females than in males and is independent of the dry weight of the butterflies; contrary to prediction, both the concentration mean and variance decrease southward. The defensive advantage of incorporating cardiac glycosides may be balanced by detrimental effects on individual viability. PMID:5043141

  5. 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...

  6. 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.

  7. 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

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

    NARCIS (Netherlands)

    Wintermans, P.C.A.; Bakker, P.A.H.M.; Pieterse, C.M.J.

    2016-01-01

    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. Her

  9. Impurities and Electronic Property Variations of Natural MoS2 Crystal Surfaces.

    Science.gov (United States)

    Addou, Rafik; McDonnell, Stephen; Barrera, Diego; Guo, Zaibing; Azcatl, Angelica; Wang, Jian; Zhu, Hui; Hinkle, Christopher L; Quevedo-Lopez, Manuel; Alshareef, Husam N; Colombo, Luigi; Hsu, Julia W P; Wallace, Robert M

    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 MoS2 will have to be controlled during crystal growth in order to provide high quality uniform materials for future device fabrication. PMID:26301428

  10. Investigation on a system to collect water vapor from the air, for the analysis of natural isotopic variation

    International Nuclear Information System (INIS)

    The development of a system to collect water vapor from air for isotopic composition analysis and its natural variation is studied. The system consists of a molecular sieve type 4A, without cooling agent and permits the choice of a sampling time varying from a few minutes to many hours through the control of the admission vapor flux. The system has been compared with other existing systems, having shown excellent performance for the collection of samples for D/H ratio analysis, with errors of the order of +- -+ 3.00/oo and +- -+ 0.60/oo in the delta sub(D) 0/oo and delta1800/oo ratios, respectively

  11. Assessment of natural variation of iron and zinc isotope ratios during an iron intervention study in lactating women of Bangladesh

    International Nuclear Information System (INIS)

    A high proportion of people living in developing countries are deficient in Fe and Zn. Accurate markers for Fe status are available, but we lack effective markers to measure Zn status. Due to limitations of any single reliable method to determine zinc status, specific information on the prevalence of deficiency in particular settings is still lacking. State of art research indicates that the isotope ratios of Zn in human tissues are not in isotopic equilibrium. Differences in readings are expected to vary by up to 20 per mille in human tissues. In this study, we will examine natural variations in Fe and Zn isotope ratios in biological samples to provide new tools to assess Fe and Zn status of individuals. During the first 18 months a pilot study will be conducted with 16 lactating women in Bangladesh. Specific objectives of this study are (a) to assess the variation in the natural isotopic composition of iron and zinc isotopes in human biological samples before and after a three-month iron supplementation period and (b) to determine the natural variation of Fe and Zn isotopes in Bangladesh diet. There will be two study groups: One malnourished and one well-nourished group. Each group will consist of mothers in two subgroups: (1) iron supplementation, (2) no supplementation. Natural variation of Fe and Zn isotope will be determined in both well-nourished and malnourished women. Fe and Zn levels in blood, faeces, urine, hair and nails, will be determined. Hemoglobin, serum ferritin and serum transferrin receptor level will be measured to determine iron status. Subjects will be followed up at home weekly to ensure the continuity of supplementation. Blood, urine, stool, hair, and nail samples will be collected on in regular intervals from day 0 to 80 with special care to limit contamination, as Zn is especially prone to environmental contamination. Representative samples of Bangladeshi foods (meat, fish, vegetables, pulses, rice) will be collected from each of the two

  12. Simple applicable methods for assessing natural hazards caused by landslides and erosion processes in torrent catchments

    Science.gov (United States)

    Tilch, N.; Melzner, S.; Janda, C.; Koçiu, A.

    2009-04-01

    The present study for the "Bucklige Welt- Wechselland" area, a mountainous region of about 1300 km² in the eastern part of Austria, was conducted under the authority of the Austrian Service for Torrent and Avalanche Control (WLV). The ultimate ambition of this study was directed towards the improvement of regional expertise by developing susceptibility maps at catchment scale, which display the disposition towards the occurrence of the mentioned processes and their bed-load-potentials. These results about hazard potential should form the basis for further planning decisions (more detailed investigations, hazard zoning) of governmental authorities responsible for the study region. Past events within the study area have shown, that besides floods, also landslides and fluvial erosion have a significant hazardous potential through their contribution to enormous bed loads and debris flows. As the interaction of dispositional and triggering factors are expected to be very complex, this regional study was carried out within a close interdisciplinary collaboration of three project partners, focusing on the main project modules "Hydrology and Climatic Impacts" (Vienna University of Technology), "Land Use and Pedology" (The Research and Training Centre for Forests, Natural Hazards and Landscape in Innsbruck) and "Geology and Geomorphology" (Geological Survey of Austria). The work was conducted using generally available data (DEM, Geology, Land Use) and field data to a minor extent. The quality and scale of these available data sources restricted the development of methods to simple approaches, which could easily be applied in the future within other areas by regional experts. The developed methodology and outcomes of the module "geology and geomorphology" are introduced on the basis of the derived susceptibility maps showing "dominant processes" and "relative bed- load- potentials".

  13. Ingestion dose caused by foodstuff consumption: differences between high and normal natural radiation areas

    International Nuclear Information System (INIS)

    The activities of 238 U, 226 Ra, 210 Pb, 228 Ra and 232 Th were determined in foodstuff samples from Buena region, which is one of the most important Brazilian monazite occurrence regions. The comparison among the radionuclide concentrations in the foodstuffs from Buena and Rio de Janeiro city showed that the foodstuffs from Buena have concentration of radium and 210 Pb 5 to 13 times higher than that one consumed by Rio de Janeiro city inhabitants. The daily intake of radionuclides by the Buena adult inhabitants were estimated to be 8.7 mBq of 238 U, 25 mBq of 232 Th, 79 mBq of 226 Ra, 94 mBq of 210 Pb and 267 mBq of 228 Ra. Comparing the radionuclide intakes between Buena and Rio de Janeiro, it is observed that in Buena the radium and 210 Pb consumption are around 4 times higher, the 232 Th consumption is around 12 times higher and the 238 U consumption is similar to that one of Rio de Janeiro city. The intake rate does not reflect directly the radionuclide concentrations found in Buena products and shows the concentration dilution caused by the foodstuffs import from other regions. The total annual effective dose was estimated to be 120 μSv for Buena and 34 μ Sv for Rio de Janeiro city adult inhabitants. Once Buena region does not produce all foodstuffs that consumes, the effective dose for Buena inhabitants is decreased by the consumption of import products. (author)

  14. 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 ...... was to determine if LV, RV and total heart volumes (THV) as well as cardiac pumping mechanisms change during physical exercise compared to rest using cardiovascular magnetic resonance (CMR)....

  15. Variation of natural background radiation in the Federal Republic of Germany

    International Nuclear Information System (INIS)

    Within the framework of a research project supported by the Federal Minister of the Interior, 30,000 measurements were conducted with scintillation dosimeters of the same type in 10 institutions distributed all over the Federal Republic of Germany, determining the local rate of gamma radiation in building (mean values). In addition, 25,000 measurements of the local dose rate of gamma radiation in the free environment as well as approximately 600 measurements were performed via gamma spectroscopy of the specific content of natural radioactive substances in building materials. The dose rate measurements were centrally evaluated by an electronic data processing system, whereby regional differences, differences depending on age and type of buildings, differences depending on the content of natural radioactive substances in building materials were taken into consideration. The results of this research program are discussed

  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

    account economic considerations. To overcome these shortcomings, we have developed an age‐structured, economic–ecological model that accounts for the dominant processes affecting natural mortality. With the goal of ultimately providing the most appropriate management advice for the operating fishery......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...... 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...

  17. 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

  18. Judgments of noticeable differences in sound fields of concert halls caused by intensity variations in early reflections

    Science.gov (United States)

    Okano, Toshiyuki

    2002-01-01

    In concert halls early reflections combine with the direct sound and with reverberation to determine the subjective rating of a room's acoustics. Of interest is how variations in the amplitudes of these early reflections are related to the subjectively just-noticeable differences (jnd) in several important acoustical parameters for their wide range encountered in existing halls. Investigated were four subjective parameters, apparent source width (ASW), loudness, intimacy and clarity, which are related to the physical measurements, [1-IACCE3], G, ITDG, and C80, defined mathematically in Beranek [Concert and Opera Halls: How They Sound (Acoustical Society of America, New York, 1996)]. Forty-eight types of sound fields were chosen in which to make variations in the amplitudes of early reflections and were reproduced electro-acoustically by multiple loudspeakers in an anechoic chamber. The results indicate that ASW and loudness are more sensitive to changes in the levels of early reflections, and were the primary parameters investigated. Although the number of subjects available with enough experience in listening classical music is limited and the measured jnd is an initial estimation, the jnd of [1-IACCE3] is measured as 0.065+/-0.015 in variations of sound field structures and the jnd of G was measured as 0.25+/-0.15 dB, which is consistent with the results of previous studies.

  19. Nonlinear dynamics of cycle-to-cycle combustion variations in a lean-burn natural gas engine

    International Nuclear Information System (INIS)

    Temporal dynamics of the combustion process in a lean-burn natural gas engine was studied by the analysis of time series of consecutive experimental in-cylinder pressure data in this work. Methods borrowed to the nonlinear dynamical system theory were applied to analyze the in-cylinder pressure time series under operating conditions with different equivalence ratio. Phase spaces were reconstructed from the in-cylinder pressure time series and Poincare section calculated from each phase space. Poincare sections show that the in-cylinder combustion process involves chaotic behavior. Furthermore, return maps plotted from time series of indicated mean effective pressure show that both nonlinear deterministic components and stochastic components are involved in the dynamics of cycle-to-cycle combustion variations in the lean burn natural gas engine. There is a transition from stochastic behavior to noisy nonlinear determinism as equivalence ratio decreases from near stoichiometric to very lean conditions

  20. Molecular basis of natural variation and environmental control of trichome patterning

    OpenAIRE

    Hauser, Marie-Theres

    2014-01-01

    Trichomes are differentiated epidermal cells on above ground organs of nearly all land plants. They play important protective roles as structural defenses upon biotic attacks such as herbivory, oviposition and fungal infections, and against abiotic stressors such as drought, heat, freezing, excess of light, and UV radiation. The pattern and density of trichomes is highly variable within natural population suggesting tradeoffs between traits positively affecting fitness such as resistance and ...

  1. Sex, death, and genetic variation: natural and sexual selection on cricket song

    OpenAIRE

    Gray, D.A.; Cade, W. H.

    1999-01-01

    Male field crickets, Gryllus integer, in Texas, USA, produce a trilled calling song that attracts female crickets, resulting in enhanced mating success. Gravid female parasitoid flies, Ormia ochracea, are also attracted to male cricket calling song, resulting in the death of the male within about seven days. Using playbacks of field-cricket calling song in the natural habitat, we show that both female crickets and female parasitoid flies prefer male calling song with average numbers of pulses...

  2. Monitoring radioactive variation of shallow formations in petroleum exploration and development blocks using natural γ spectroscopy

    International Nuclear Information System (INIS)

    Natural γ spectroscopy logging are run for shallow formations in four wells near the Yellow River delta area. The thorium content of the shallow formation in well Laohuanghekou is higher than that of other wells. The uranium content in sea water is higher than that in shallow formations on land. Radioactivity is higher in mature area than in new frontier area. It indicates that petroleum development have certain effect on local ecological environment. (authors)

  3. The measurement of the ionospheric total content variations caused by a powerful radio emission of "Sura" facility on a network of GNSS-receivers

    Science.gov (United States)

    Nasyrov, I. A.; Kogogin, D. A.; Shindin, A. V.; Grach, S. M.; Zagretdinov, R. V.

    2016-02-01

    Observations of the perturbations of total electron content (TEC) caused by a powerful radio emission of "Sura" facility (Radio Physical Research Institute, N. Novgorod) were carried out during several experimental campaigns from March of 2010 to March 2013. In this paper the data of experimental measurements of TEC-variations conducted on March, 15, 2010 and on March, 12, 2013, are presented. 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 along the geomagnetic latitude: Vasilsursk (56 °08‧ N, 46 °05‧ E), Zelenodolsk (55 °52‧ N, 48 °33‧ E) and Kazan (55 °48‧ N, 49 °08‧ E). In the experiments radio path from GNSS satellite to Vasilsursk passed over the disturbed region of ionosphere, but radio paths to Zelenodolsk and to Kazan did not. However, TEC-variations correlated with pumping of ionosphere by "Sura" facility were detected for all up to three ground measurements sites. Magnitudes of TEC-variations reached up to ∼ 0.6 - 0.7 TECU. The speculation that a sharp gradient of the electron density formed at the border of the main lobe of "Sura" facility may cause the generation of IGW is presented.

  4. Variation in oxygen isotope ratio of dissolved orthophosphate induced by uptake process in natural coral holobionts

    Science.gov (United States)

    Ferrera, Charissa M.; Miyajima, Toshihiro; Watanabe, Atsushi; Umezawa, Yu; Morimoto, Naoko; San Diego-McGlone, Maria Lourdes; Nadaoka, Kazuo

    2016-06-01

    A model incubation experiment using natural zooxanthellate corals was conducted to evaluate the influence of phosphate uptake by coral holobionts on oxygen isotope ratio of dissolved PO4 3- (δ18Op). Live coral samples of Acropora digitifera, Porites cylindrica, and Heliopora coerulea were collected from coral reefs around Ishigaki Island (Okinawa, Japan) and Bolinao (northern Luzon, Philippines) and incubated for 3-5 d after acclimatization under natural light conditions with elevated concentrations of PO4 3-. Phosphate uptake by corals behaved linearly with incubation time, with uptake rate depending on temperature. δ18Op usually increased with time toward the equilibrium value with respect to oxygen isotope exchange with ambient seawater, but sometimes became higher than equilibrium value at the end of incubation. The magnitude of the isotope effect associated with uptake depended on coral species; the greatest effect was in A. digitifera and the smallest in H. coerulea. However, it varied even within samples of a single coral species, which suggests multiple uptake processes with different isotope effects operating simultaneously with varying relative contributions in the coral holobionts used. In natural environments where concentrations of PO4 3- are much lower than those used during incubation, PO4 3- is presumably turned over much faster and the δ18Op easily altered by corals and other major primary producers. This should be taken into consideration when using δ18Op as an indicator of external PO4 3- sources in coastal ecosystems.

  5. Physically-based modeling of drag force caused by natural woody vegetation

    Science.gov (United States)

    Järvelä, J.; Aberle, J.

    2014-12-01

    Riparian areas and floodplains are characterized by woody vegetation, which is an essential feature to be accounted for in many hydro-environmental models. For applications including flood protection, river restoration and modelling of sediment processes, there is a need to improve the reliability of flow resistance estimates. Conventional methods such as the use of lumped resistance coefficients or simplistic cylinder-based drag force equations can result in significant errors, as these methods do not adequately address the effect of foliage and reconfiguration of flexible plant parts under flow action. To tackle the problem, physically-based methods relying on objective and measurable vegetation properties are advantageous for describing complex vegetation. We have conducted flume and towing tank investigations with living and artificial plants, both in arrays and with isolated plants, providing new insight into advanced parameterization of natural vegetation. The stem, leaf and total areas of the trees confirmed to be suitable characteristic dimensions for estimating flow resistance. Consequently, we propose the use of leaf area index and leaf-to-stem-area ratio to achieve better drag force estimates. Novel remote sensing techniques including laser scanning have become available for effective collection of the required data. The benefits of the proposed parameterization have been clearly demonstrated in our newest experimental studies, but it remains to be investigated to what extent the parameter values are species-specific and how they depend on local habitat conditions. The purpose of this contribution is to summarize developments in the estimation of vegetative drag force based on physically-based approaches as the latest research results are somewhat dispersed. In particular, concerning woody vegetation we seek to discuss three issues: 1) parameterization of reconfiguration with the Vogel exponent; 2) advantage of parameterizing plants with the leaf area

  6. 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

  7. Identification of Genes Responsible for Natural Variation in Volatile Content Using Next-Generation Sequencing Technology.

    Science.gov (United States)

    Amaya, Iraida; Pillet, Jeremy; Folta, Kevin M

    2016-01-01

    Identification of the genes controlling the variation of key traits remains a challenge for plant researchers and represents a goal for the development of functional markers and their implementation in marker-assisted crop breeding. As an example we describe the identification of volatile organic compounds (VOCs) that segregate as single locus or mayor quantitative trait loci (QTL) in strawberry F1 segregating populations. Next, we describe a fast and efficient method for RNA extraction in strawberry that yields high-quality RNA for downstream RNA-seq analysis. Finally, two alternative methods for analysis of global transcript expression in contrasting lines will be described in order to identify the candidate gene and genes with differential expression using RNA-seq. PMID:26577779

  8. Natural-Scale Lava Flow Experiments on Video: Variations with Temperature, Slope, and Effusion Rate

    Science.gov (United States)

    Karson, J. A.; Wysocki, R.; Edwards, B. R.; Lev, E.

    2013-12-01

    Investigations of active basaltic lava flows and analog materials show that flow dynamics and final flow morphology are strongly determined by the rapidly evolving rheology of the lava crust which constrains the downslope advance of the lava flow. The non-dimensional factor Ψ (ratio of the time scale of crust formation to advective heat loss) provides a useful means of comparing different flows. The key parameters that control Ψ include the melt viscosity, temperature, effusion rate, and slope. Experimental lava flows, up to several meters long created in the Syracuse University Lava Project permit these variables to be investigated independently and in combination in volume-limited flows (inflated lobes, break-outs, and bubbles (limu o'Pele), that provide additional information on lava crust development. New, continuous flow (cooling-limited) experiments show downslope variations under constant flow conditions.

  9. Evaluation on changes caused by volcanic activities in the groundwater environment as a natural barrier for the HLW disposal. Literature survey and groundwater observation conducted at Mt. Iwate

    International Nuclear Information System (INIS)

    It is very important in the site characterization for the HLW disposal to understand changes in geochemical performances caused by volcanic activities in the groundwater environment as the natural barrier. The various effects and its magnitude of changes were listed up and were filed from literature surveys of the correlation between volcanic activities and hydrological can geochemical changes (e.g. water temperature, water pressure, water level, dissolved gas concentration of He and Rn, isotopic ratio of He, and chloride concentration) in volcanic aquifer. However, it is difficult to evaluate the magnitude of impacts, which volcanic activities will give to the groundwater environment in the natural barrier, through only the literature surveys. We have started monitoring of groundwater level and changes in groundwater quality, since volcanic activities have enhanced at Mt. Iwate from June in 1998. Judging from variation of isotopic ratio of dissolved He in groundwater, a prompt and sharp signals indicating volcanic activities will easily be found in shallow groundwater and discharged ponds. On the other hands, geochemical conditions in deep groundwater surroundings from some 100 m to 1000 m deep will be very stable, if the area being more than 5 km apart from the volcanic active center. Consequently, our observed results suggest that the groundwater environment which is not directly disturbed by the underground magmatic activities spreads under the area that is connected to trench side of the volcanic front. (author)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Gabriel, Mourad W; Woods, Leslie W; Wengert, Greta M; Stephenson, Nicole; Higley, J Mark; Thompson, Craig; Matthews, Sean M; Sweitzer, Rick A; Purcell, Kathryn; Barrett, Reginald H; Keller, Stefan M; Gaffney, Patricia; Jones, Megan; Poppenga, Robert; Foley, Janet E; Brown, Richard N; Clifford, Deana L; Sacks, Benjamin N

    2015-01-01

    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. PMID:26536481

  12. 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.

  13. Seasonal variation of nutrients and energy in tambaqui's (Colossoma Macropomum Cuvier, 1818) natural food

    OpenAIRE

    SILVA J. A. M. da; PEREIRA-FILHO M.; M. I. de OLIVEIRA-PEREIRA

    2000-01-01

    The aim of this study was to evaluate the importance of fruits and seeds as food items in the natural diet of the tambaqui (Colossoma macropomum). During one year, tambaqui's stomach contents were collected, and their nutritional and energetic values were determined. During the flooding period, and while the river water was rising, which coincided with a high availability of fruits and seeds, the protein content of food was low (11%-15% of dry matter basis), whereas in the dry season, when ta...

  14. 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.M.

    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.

  15. 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

  16. 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

  17. 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. PMID:24851925

  18. 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.

  19. Photo-centric variability of quasars caused by variations in their inner structure: Consequences on Gaia measurements

    CERN Document Server

    Popovic, Luka C; Stalevski, Marko; Anton, Sonia; Andrei, Alexandre H; Kovacevic, Jelena; Baes, Maarten

    2011-01-01

    We study the photocenter position variability due to variations in the quasar inner structure. We consider variability in the accretion disk emissivity and torus structure variability due to different illumination by the central source. We discuss possible detection of these effects by Gaia. Observations of the photocenter variability in two AGNs, SDSS J121855+020002 and SDSS J162011+1724327 have been reported and discussed. With investigation of the variations in the quasar inner structure we explore how much this effect can affect the position determination and whether it can be (or not) detected with Gaia mission. We used (a) a model of a relativistic disk, including the perturbation that can increase brightness of a part of the disk, and consequently offset the photocenter position, and (b) a model of a dusty torus which absorbs and re-emits the incoming radiation from accretion disk. We estimated the value of the photocenter offset due to these two effects. We found that perturbations in the inner struct...

  20. 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

  1. Seasonal variation of nutrients and energy in tambaqui's (Colossoma Macropomum Cuvier, 1818) natural food.

    Science.gov (United States)

    Silva, J A; Pereira-Filho, M; Oliveira-Pereira, M I

    2000-11-01

    The aim of this study was to evaluate the importance of fruits and seeds as food items in the natural diet of the tambaqui (Colossoma macropomum). During one year, tambaqui's stomach contents were collected, and their nutritional and energetic values were determined. During the flooding period, and while the river water was rising, which coincided with a high availability of fruits and seeds, the protein content of food was low (11%-15% of dry matter basis), whereas in the dry season, when tambaqui fed mainly zooplankton, there was a high protein content (45%-57% of dry matter basis). Lipid, carbohydrate, crude fiber, ash and gross energy contents of the diet varied depending on the river water level and the food items ingested. PMID:11241958

  2. Seasonal variation of nutrients and energy in tambaqui's (Colossoma Macropomum Cuvier, 1818 natural food

    Directory of Open Access Journals (Sweden)

    SILVA J. A. M. da

    2000-01-01

    Full Text Available The aim of this study was to evaluate the importance of fruits and seeds as food items in the natural diet of the tambaqui (Colossoma macropomum. During one year, tambaqui's stomach contents were collected, and their nutritional and energetic values were determined. During the flooding period, and while the river water was rising, which coincided with a high availability of fruits and seeds, the protein content of food was low (11%-15% of dry matter basis, whereas in the dry season, when tambaqui fed mainly zooplankton, there was a high protein content (45%-57% of dry matter basis. Lipid, carbohydrate, crude fiber, ash and gross energy contents of the diet varied depending on the river water level and the food items ingested.

  3. Assessing the Total Mortality Caused by Two Species of Trichogramma on Its Natural Host Plutella xylostella (L.) at Different Temperatures.

    Science.gov (United States)

    Marchioro, C A; Krechemer, F S; Foerster, L A

    2015-06-01

    Trichogramma pretiosum Riley and Trichogramma atopovirilia Oatman & Platner are natural enemies of Plutella xylostella (L.) in Southern Brazil. Laboratory studies to evaluate parasitoids performance under different conditions, such as temperature regimes, are necessary to assess their potential as biocontrol agents of P. xylostella. In most studies involving Trichogramma, parasitism rate is the main parameter used to evaluate parasitoid performance, ignoring that parasitoids can cause egg mortality by feeding on the host content and/or to multiple drilling without laying eggs. This study was conducted to investigate three main issues: how temperature affects T. pretiosum and T.atopovirilia development on eggs of P. xylostella, whether or not these species respond differently to temperature, and how important is the mortality they cause besides parasitism on P. xylostella. Temperature effects (from 10 to 30°C) on development, survival, parasitism rate, mortality, and total mortality caused by T. pretiosum and T. atopovirilia on eggs of P. xylostella were evaluated. Temperature affected the development time, female longevity, parasitism rate, mortality not directly related to parasitoid larval development, and total mortality caused on the host. No significant differences were recorded for the estimated thermal requirements for T. pretiosum and T. atopovirilia. However, the higher mortality caused by T. pretiosum indicates that this parasitoid is the most suitable to be used against P. xylostella. Also, the results suggest that the use of parasitism rate as the only parameter to evaluate the performance of T. pretiosum and T. atopovirilia may underestimate the potential of these parasitoids in regulating pest populations. PMID:26013271

  4. Extensive sequence variation in rice blast resistance gene Pi54 makes it broad spectrum in nature

    Directory of Open Access Journals (Sweden)

    Shallu eThakur

    2015-05-01

    Full Text Available Rice blast resistant gene, Pi54 cloned from rice line, Tetep, is effective against diverse isolates of Magnaporthe oryzae. In this study, we prospected the allelic variants of the dominant blast resistance gene from a set of 92 rice lines to determine the nucleotide diversity, pattern of its molecular evolution, phylogenetic relationships and evolutionary dynamics, and to develop allele specific markers. High quality sequences were generated for homologs of Pi54 gene. Using comparative sequence analysis, InDels of variable sizes in all the alleles were observed. Profiling of the selected sites of SNP (Single Nucleotide Polymorphism and amino acids (N sites ≥ 10 exhibited constant frequency distribution of mutational and substitutional sites between the resistance and susceptible rice lines, respectively. A total of 50 new haplotypes based on the nucleotide polymorphism was also identified. A unique haplotype (H_3 was found to be linked to all the resistant alleles isolated from indica rice lines. Unique leucine zipper and tyrosine sulfation sites were identified in the predicted Pi54 proteins. Selection signals were observed in entire coding sequence of resistance alleles, as compared to LRR domains for susceptible alleles. This is a maiden report of extensive variability of Pi54 alleles in different landraces and cultivated varieties, possibly, attributing broad-spectrum resistance to Magnaporthe oryzae. The sequence variation in two consensus region: 163 bp and 144 bp were used for the development of allele specific DNA markers. Validated markers can be used for the selection and identification of better allele(s and their introgression in commercial rice cultivars employing marker assisted selection.

  5. 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.

  6. Diurnal variation of surface fluxes during thorough drying (or severe drought) of natural prairie

    International Nuclear Information System (INIS)

    Experimental data recorded over a natural tall grass prairie during the later stages of drying in the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment-1987 showed (1) that the total daily values of evaporation exhibited a kind of second stage of drying behavior with a t-1/2 dependency at the daily timescale and (2) that this day-to-day evolution was modulated by the available energy at the surface, that is, the hourly radiation input. This allowed a simple description of the phenomenon by combining a desorptive diffusion-type parameterization for the total daily evaporation or for its dimensionless counterpart (such as Priestley and Taylor's alpha, the evaporative fraction, and a few others), with an assumption of self-preservation in the surface energy budget during the daytime hours. The resulting formulation, which involves two timescales, a daily and an hourly, was able to reproduce daytime hourly flux values over a 2-week period of intensive drying. The method can also be useful in the disaggregation of daily, or even weekly, evaporation into hourly values

  7. 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.

  8. 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.

  9. 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. PMID:26555511

  10. Variation in endogenous oxidative stress in Escherichia coli natural isolates during growth in urine

    Directory of Open Access Journals (Sweden)

    Aubron Cecile

    2012-06-01

    Full Text Available Abstract Background Uropathogenic strains of Escherichia coli cause symptomatic infections whereas asymptomatic bacteriuria (ABU strains are well adapted for growth in the human urinary tract, where they establish long-term bacteriuria. Human urine is a very complex growth medium that could be perceived by certain bacteria as a stressful environment. To investigate a possible imbalance between endogenous oxidative response and antioxidant mechanisms, lipid oxidative damage estimated as thiobarbituric acid reactive substances (TBARS content was evaluated in twenty-one E. coli belonging to various pathovars and phylogenetic groups. Antioxidant defense mechanisms were also analysed. Results During exponential growth in urine, TBARS level differs between strains, without correlation with the ability to grow in urine which was similarly limited for commensal, ABU and uropathogenic strains. In addition, no correlation between TBARS level and the phylogroup or pathogenic group is apparent. The growth of ABU strain 83972 was associated with a high level of TBARS and more active antioxidant defenses that reduce the imbalance. Conclusions Our results indicate that growth capacity in urine is not a property of ABU strains. However, E. coli isolates respond very differently to this stressful environment. In strain ABU 83972, on one hand, the increased level of endogenous reactive oxygen species may be responsible for adaptive mutations. On the other hand, a more active antioxidant defense system could increase the capacity to colonize the bladder.

  11. Muerte por proyectil de arma de fuego con orificio de entrada natural Death caused by a projectile gun with a natural entrance hole

    Directory of Open Access Journals (Sweden)

    F. Sánchez

    2010-09-01

    Full Text Available Un proyectil de arma de fuego puede penetrar en el organismo por cualquier parte, originando una lesión cuya morfología puede ser muy variada en función de múltiples factores. No obstante, en ocasiones el lugar de entrada del proyectil puede coincidir con un orificio natural del cuerpo, por lo que la lesión externa no existe. Presentamos un caso de muerte por un único proyectil de arma de fuego cuyo lugar de penetración es uno de los orificios nasales, con la particularidad de que la bala quedó alojada en el interior del cuerpo, no existiendo por tanto lesión de salida. En estas circunstancias se hacen indispensables las técnicas radiológicas como paso previo a la autopsia.A firearm projectile can penetrate through any place of the body, causing injuries whose morphology can be different depending on several factors. However, sometimes the shotgun entrance hole coincides with a body orifice, so the entrance wound could not exist. The authors present a case of a death caused by a single firearm projectile which penetrated through one of the nostrils. The bullet was lodged inside of the body without an exit wound. In those circumstances the radiological techniques are indispensable before to perform the autopsy.

  12. Natural genetic variation in cassava (Manihot esculenta Crantz) landraces as a tool for gene discovery

    International Nuclear Information System (INIS)

    Cassava landraces are the earliest form of the modern cultivars and represents the first step in cassava domestication. Our forward genetic analysis uses this resource to discover spontaneous mutations in the sucrose/starch and carotenoid synthesis/accumulation and to develop both evolutionary and breeding perspective of gene function related to those traits. Biochemical phenotype variants for the synthesis and accumulation of carotenoid, free sugar and starch were identified. Six subtractive cDNA libraries were prepared to construct a high quality (phred > 20) EST database with 1645 entries. Macroarray analysis was performed to identify differentially expressed gene aiming to identify candidate gene related to sugary phenotype. cDNA sequence for gene coding for specific enzymes in the two pathways were obtained. Gene expression analysis for coding specific enzymes was performed by RNA blot and Real Time PCR analysis. Chromoplastassociated proteins of yellow storage root were fractionated and a peptide sequence data base with 906 entries sequences (MASCOT validated) was constructed. For the sucrose/starch metabolism a sugary class of cassava was identified carrying mutation in the BEI and GBSS mutation. For the pigmented cassava a pink color phenotype showed absence of expression of the gene CasLYB while an intense yellow phenotype showed a down regulation of the gene CasHYb. Heat shock proteins were identified as the major proteins associated with chromoplast. Genetic diversity for the GBSS gene in the natural population identified 22 haplotype and a large nucleotide diversity in four subset of population. Single segregating population derived from F2, half sib and S1 population showed segregation for sugary phenotype (93% of the individuals), waxy phenotype (38% of the individuals) and glycogen like starch (2% of the individuals). Here we summarize our current results for the genetic analysis of this variants and recent progress in the direction of mapping of

  13. Natural Genetic Variation in Cassava (Manihot esculenta Crantz) Landraces: A Tool for Gene Discovery

    International Nuclear Information System (INIS)

    Cassava landraces are the earliest form of the modern cultivars and represent the first step in cassava domestication. Our forward genetic analysis uses this resource to discover spontaneous mutations in the sucrose/ starch and carotenoid synthesis/accumulation and to develop both an evolutionary and breeding perspective of gene function related to those traits. Biochemical phenotype variants for the synthesis and accumulation of carotenoid, free sugar and starch were identified. Six subtractive cDNA libraries were prepared to construct a high quality (phred > 20) EST database with 1,645 entries. Macroarray and micro-array analysis was performed to identify differentially expressed genes aiming to identify candidate genes related to sugary phenotype and carotenoid diversity. cDNA sequence for gene coding for specific enzymes in the two pathways was obtained. Gene expression analysis for coding specific enzymes was performed by RNA blot and Real Time PCR analysis. Chromoplast-associated proteins of yellow storage root were fractionated and a peptide sequence database with 906 entries sequences (MASCOT validated) was constructed. For the sucrose/starch, metabolism a sugary class of cassava was identified, carrying a mutation in the BEI and GBSS genes. For the pigmented cassava, a pink color phenotype showed absence of expression of the gene CasLYB, while an intense yellow phenotype showed a down regulation of the gene CasHYb. Heat shock proteins were identified as the major proteins associated with carotenoid. Genetic diversity for the GBSS gene in the natural population identified 22 haplotypes and a large nucleotide diversity in four subsets of population. Single segregating population derived from F2, half-sibling and S1 population showed segregation for sugary phenotype (93% of individuals), waxy phenotype (38% of individuals) and glycogen like starch (2% of individuals). Here we summarize our current results for the genetic analysis of these variants and recent

  14. The fibrocartilaginous sesamoid: a cause of size and signal variation in the normal distal posterior tibial tendon

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the presence of fibrocartilage within the distal posterior tibial tendon (PTT) before its division correlating with size and signal variation on MR images through a radio-anatomic and pathologic study. Eight fresh cadaveric feet underwent MR imaging were cut into 4-mm slices in the axial plane. The PTT specimens were harvested at the tendon distal portion before its division and sent to pathology. Thirty-three asymptomatic subjects underwent axial double-echo turbo-spin-echo MR imaging. Proximal and distal PTT signal and diameter were evaluated. In cadavers, every PTT flared distally. Intratendinous fibrocartilage and ossified sesamoid were found in, respectively, 87.5 and 12.5% of the cases. Distal PTT flaring was demonstrated in 100% of the asymptomatic subjects (mean diameter 8 mm). An intratendinous high signal intensity on proton-density-weighted images and sesamoid bone were evidenced in, respectively, 36 and 33% of the cases. Proximally, PTT presented a 4-mm mean diameter and was hypointense in 100% of the cases. Only one accessory navicular bone was detected. Laterally off-centered increased intratendinous signal intensity as well as PTT distal widening with otherwise normal MR imaging features are related to an intratendinous fibrocartilage. (orig.)

  15. The fibrocartilaginous sesamoid: a cause of size and signal variation in the normal distal posterior tibial tendon

    Energy Technology Data Exchange (ETDEWEB)

    Delfaut, E.M.; Bieganski, A.; Cotten, A. [Department of Skeletal Radiology, Roger Salengro Hospital, CHRU of Lille, Bd du Professeur Jules Leclercq, 59037, Lille Cedex (France); Demondion, X. [Department of Skeletal Radiology, Roger Salengro Hospital, CHRU of Lille, Bd du Professeur Jules Leclercq, 59037, Lille Cedex (France); Department of Anatomy, Faculty of Medicine, Place de Verdun, 59037, Lille Cedex (France); Cotten, H. [Pathology Laboratory, 128 Bd de la Liberte, 59000, Lille Cedex (France); Mestdagh, H. [Department of Orthopaedic Surgery, Roger Salengro Hospital, CHRU of Lille, Bd du Professeur Jules Leclercq, 59037, Lille Cedex (France)

    2003-12-01

    The aim of this study was to investigate the presence of fibrocartilage within the distal posterior tibial tendon (PTT) before its division correlating with size and signal variation on MR images through a radio-anatomic and pathologic study. Eight fresh cadaveric feet underwent MR imaging were cut into 4-mm slices in the axial plane. The PTT specimens were harvested at the tendon distal portion before its division and sent to pathology. Thirty-three asymptomatic subjects underwent axial double-echo turbo-spin-echo MR imaging. Proximal and distal PTT signal and diameter were evaluated. In cadavers, every PTT flared distally. Intratendinous fibrocartilage and ossified sesamoid were found in, respectively, 87.5 and 12.5% of the cases. Distal PTT flaring was demonstrated in 100% of the asymptomatic subjects (mean diameter 8 mm). An intratendinous high signal intensity on proton-density-weighted images and sesamoid bone were evidenced in, respectively, 36 and 33% of the cases. Proximally, PTT presented a 4-mm mean diameter and was hypointense in 100% of the cases. Only one accessory navicular bone was detected. Laterally off-centered increased intratendinous signal intensity as well as PTT distal widening with otherwise normal MR imaging features are related to an intratendinous fibrocartilage. (orig.)

  16. Proposed causes and mechanisms for variation in photosynthesis of Quercus rubra along an urban to rural gradient

    Directory of Open Access Journals (Sweden)

    Stephanie Searle

    2007-06-01

    Full Text Available Forests in the northeastern United States are currently sequestering atmospheric carbon dioxide released by fossil fuels. The effects of accelerating urbanization and global warming on plant carbon uptake will thus have important consequences for future atmospheric carbon dioxide concentrations and climate change. The urban environment of New York City(NYC has been shown to produce increased plant growth and carbon sequestration in Populus deltoides. Here we investigate the effects of NYC’s urban environment on native red oaks (Quercus rubra L.. We grew four-year-old oak seedlings at four sites along an urban to rural gradient from NYC to the Catskills for 1.5 years. We measured the short-term response of photosynthesis to [CO2] in three seedlings at each site, as well as environmental parameters. Photosynthesis was highest in NYC, second highest in the Catskills, and lowest at the two intermediate sites. Comparison of photosynthesis data with environmental variables suggests that the combined effect of diurnal temperature range, [CO2], and ozone account for most of the variation in photosynthesis and growth along the gradient. These results and interpretations differ from those of Gregg et al. (2003; we suggest that these differences are due to the species tested, and that Quercus rubra may provide a more accurate indicator of how urbanization and climate change will affect carbon cycling in forests in the eastern United States.

  17. 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, N;

    2012-01-01

    AIMS/HYPOTHESIS: 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 (Ox......Phos) contributes to type 2 diabetes susceptibility or influences diabetes-related metabolic traits. METHODS: OxPhos gene variants (n = 10) that had been nominally associated (p < 0.01) with type 2 diabetes in a recent genome-wide meta-analysis (n = 10,108) were selected for follow-up in 3,599 type 2 diabetic and 4......,956 glucose-tolerant Danish individuals. A meta-analysis of these variants was performed in 11,729 type 2 diabetic patients and 43,943 non-diabetic individuals. The impact on OGTT-derived metabolic traits was evaluated in 5,869 treatment-naive individuals from the Danish Inter99 study. RESULTS: The minor...

  18. Natural variation in methane emission of sheep fed on a lucerne pellet diet is unrelated to rumen ciliate community type.

    Science.gov (United States)

    Kittelmann, Sandra; Pinares-Patiño, Cesar S; Seedorf, Henning; Kirk, Michelle R; McEwan, John C; Janssen, Peter H

    2016-02-01

    Only limited information is available on the roles of different rumen ciliate community types, first described by Eadie in 1962, in enteric methane (CH4) formation by their ruminant hosts. If the different types were differentially associated with CH4 formation, then ciliate community typing could be used to identify naturally high and low CH4-emitting animals. Here we measured the CH4 yields [g CH4 (kg feed dry matter intake, DMI)- 1] of 118 sheep fed a standard pelleted lucerne diet at two different times, at least 2 weeks apart. There were significant differences (P sheep selected as high [16.7 ± 1.5 g CH4 (kg DMI)- 1] and low emitters [13.3 ± 1.5 g CH4 (kg DMI)- 1]. A rumen sample was collected after each of the two measurements, and ciliate composition was analysed using barcoded 454 Titanium pyrosequencing of 18S rRNA genes. The genera found, in order of mean relative abundance, were Epidinium, Entodinium, Dasytricha, Eudiplodinium, Polyplastron, Isotricha and Anoplodinium-Diplodinium, none of which was significantly correlated with the CH4 emissions ranking associated with the rumen sample. Ciliate communities naturally assembled into four types (A, AB, B and O), characterized by the presence and absence of key genera. There was no difference in CH4 yield between sheep that harboured different ciliate community types, suggesting that these did not underlie the natural variation in CH4 yields. Further research is needed to unravel the nature of interactions between ciliate protozoa and other rumen micro-organisms, which may ultimately lead to contrasting CH4 emission phenotypes. PMID:26813792

  19. Seasonal variations of natural ventilation and radon-222 exhalation in a slightly rising dead-end tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Perrier, Frederic [Equipe de Geomagnetisme, Institut de Physique du Globe de Paris UMR7154 et universite Denis-Diderot Paris VII, 4 Place Jussieu, 75005 Paris (France)], E-mail: perrier@ipgp.jussieu.fr; Richon, Patrick [Equipe Geologie des Systemes Volcaniques, Institut de Physique du Globe de Paris UMR7154, 4 Place Jussieu, 75005 Paris (France); Laboratoire Hydrogeochimie et Etudes de sites, Departement Analyse Surveillance Environnement, Commissariat a l' energie atomique, F-91680 Bruyeres-le-Chatel (France); Gautam, Umesh; Tiwari, Dilli Ram; Shrestha, Prithvi; Sapkota, Soma Nath [National Seismic Centre, Department of Mines and Geology, Lainchaur, Kathmandu (Nepal)

    2007-10-15

    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{sup 3} Bq m{sup -3} to 10 x 10{sup 3} Bq m{sup -3} is observed from May to September (rainy summer season), the concentration remains at a low level of about 200 Bq m{sup -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.

  20. Seasonal variations of natural ventilation and radon-222 exhalation in a slightly rising dead-end tunnel

    International Nuclear Information System (INIS)

    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 103 Bq m-3 to 10 x 103 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

  1. Natural Variation in Fish Transcriptomes: Comparative Analysis of the Fathead Minnow (Pimephales promelas and Zebrafish (Danio rerio.

    Directory of Open Access Journals (Sweden)

    Rong-Lin Wang

    Full Text Available Fathead minnow and zebrafish are among the most intensively studied fish species in environmental toxicogenomics. To aid the assessment and interpretation of subtle transcriptomic effects from treatment conditions of interest, better characterization and understanding are needed for natural variation in gene expression among fish individuals from lab cultures. Leveraging the transcriptomics data from a number of our toxicogenomics studies conducted over the years, we conducted a meta-analysis of nearly 600 microarrays generated from the ovary tissue of untreated, reproductively mature fathead minnow and zebrafish samples. As expected, there was considerable batch-to-batch transcriptomic variation; this "batch-effect" appeared to differentially impact subsets of fish transcriptomes in a nonsystematic way. Temporally more closely spaced batches tended to share a greater transcriptomic similarity among one another. The overall level of within-batch variation was quite low in fish ovary tissue, making it a suitable system for studying chemical stressors with subtle biological effects. The observed differences in the within-batch variability of gene expression, at the levels of both individual genes and pathways, were probably both technical and biological. This suggests that biological interpretation and prioritization of genes and pathways targeted by experimental conditions should take into account both their intrinsic variability and the size of induced transcriptional changes. There was significant conservation of both the genomes and transcriptomes between fathead minnow and zebrafish. The high degree of conservation offers promising opportunities in not only studying fish molecular responses to environmental stressors by a comparative biology approach, but also effective sharing of a large amount of existing public transcriptomics data for developing toxicogenomics applications.

  2. Daily variation in natural disaster casualties: information flows, safety, and opportunity costs in tornado versus hurricane strikes.

    Science.gov (United States)

    Zahran, Sammy; Tavani, Daniele; Weiler, Stephan

    2013-07-01

    Casualties from natural disasters may depend on the day of the week they strike. With data from the Spatial Hazard Events and Losses Database for the United States (SHELDUS), daily variation in hurricane and tornado casualties from 5,043 tornado and 2,455 hurricane time/place events is analyzed. Hurricane forecasts provide at-risk populations with considerable lead time. Such lead time allows strategic behavior in choosing protective measures under hurricane threat; opportunity costs in terms of lost income are higher during weekdays than during weekends. On the other hand, the lead time provided by tornadoes is near zero; hence tornados generate no opportunity costs. Tornado casualties are related to risk information flows, which are higher during workdays than during leisure periods, and are related to sheltering-in-place opportunities, which are better in permanent buildings like businesses and schools. Consistent with theoretical expectations, random effects negative binomial regression results indicate that tornado events occurring on the workdays of Monday through Thursday are significantly less lethal than tornados that occur on weekends. In direct contrast, and also consistent with theory, the expected count of hurricane casualties increases significantly with weekday occurrences. The policy implications of observed daily variation in tornado and hurricane events are considered. PMID:23126406

  3. Properties and nature of Be stars: 29. Orbital and long-term spectral variations of \\gamma\\ Cassiopei\\ae

    CERN Document Server

    Nemravová, J; Koubský, P; Miroshnichenko, A; Yang, S; Šlechta, M; Buil, C; Korčáková, D; Votruba, V

    2011-01-01

    A detailed analysis of more than 800 electronic high-resolution spectra of gamma Cas, which were obtained during a time interval of over 6000 days (16.84 yrs) at several observatories, documents the smooth variations in the density and/or extend of its circumstellar envelope. We found a clear anticorrelation between the peak intensity and FWHM of the H alpha emission, which seems to agree with recent models of such emission lines. The main result of this study is a confirmation of the binary nature of the object, determination of a reliable linear ephemeris T_{min.RV} = HJD (2452081.9$\\pm$0.6) + (203.52$\\pm$0.08)*E, and a rather definitive set of orbital elements. We clearly demonstrated that the orbit is circular within the limits of accuracy of our measurements and has a semi-amplitude of radial-velocity curve of 4.30$\\pm$0.09 (km/s). No trace of the low-mass secondary was found. The time distribution of our spectra does not allow a reliable investigation of rapid spectral variations, which are undoubtedly ...

  4. Spatial variations in the trophic structure of soil animal communities in boreal forests of Pechora-Ilych Nature Reserve

    Science.gov (United States)

    Goncharov, A. A.; Khramova, E. Yu.; Tiunov, A. V.

    2014-05-01

    Soil animal communities and detrital food webs are spatially compartmentalized. In old-growth boreal forests the dynamics of dominating plant species forms a considerable heterogeneity of edaphic conditions in the soil layer. We demonstrate a strong difference in total and relative abundance of main trophic groups of soil macrofauna in four microsites, i.e. under tree crowns, in gaps, in mounds and in pits created by fallen spruce trees. The variation in the functional structure of soil animal communities is likely related to different availability of key energy resources (leaf litter, roots and root deposits) in the microsites studied. However, results of the stable isotope analysis suggest that mobile litter-dwelling predators occupy very similar trophic positions in different microsites. The compartmentalization of soil invertebrate communities caused by the vegetation-induced mosaic of edaphic conditions seemingly does not lead to spatial isolation of local food webs that are integrated at the top trophic levels.

  5. 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; Willemsen, M A A P; Sperl, W; Laugel, V; Ostergaard, E; Tarnopolsky, M; Martin, M A; Nesbitt, V; Fletcher, J; Edvardson, S; Procaccio, V; Slama, A; van den Heuvel, L P W J; Smeitink, J A M

    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....... Age at presentation may vary, but is generally within the first year of life. The most prevalent symptoms include hypotonia, nystagmus, respiratory abnormalities, pyramidal signs, dystonia, psychomotor retardation or regression, failure to thrive, and feeding problems. Characteristic symptoms include...

  6. 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.

  7. Radiation exposure of the population and indoor radiation levels in The Netherlands caused by natural gamma sources

    International Nuclear Information System (INIS)

    An estimate has been made of gamma doses to the population in the Netherlands, caused by natural radiation sources encountered in the environment. Data are given, derived from two independent types of measurements: 1. Exposure/dose rate measurements in the living environment (private houses as well as workplaces), using a high pressure ionization chamber and thermoluminescent dosemeters (TLD) respectively and 2. Individual monitoring, using TLD. The study included some 750 individuals, 400 houses and 275 workplaces. The participants were selected and divided into two groups on the basis of their location in areas of relatively high and low terrestrial radiation level respectively. Distinction was made between three categories of individuals with respect to their patterns of life. An estimate was made of the influence of the terrestrial component of the natural background and of some typical building materials on the indoor radiation level. An average indoor exposure rate of 9.4 μR.h-1 (6.7 x 10-13 C0144.s)-1) and a dose rate of 9.3 μrad.h-1 (93 nGy.h-1) for individuals were found, both with a standard deviation of 15-20%. (Auth.)

  8. A common cause: natural gas community pulls together for a fresh assault on the continental energy market

    International Nuclear Information System (INIS)

    Anticipated effects of the proposed merger of TransCanada Pipelines Ltd and Nova Corporation, and the answers provided by the companies to the Alberta Energy and Utilities Board, the natural gas community and their own employees, were discussed. The answers received were not entirely satisfactory since the merger has been moved along on the basis of intuitive expectations rather than on the basis of carefully examined benefits, in order to avoid causing harm by taking the time to demand complete answers. At the same time, TransCanada and Nova were busy working out an agreement with the natural gas community which will put producers on a new 'netback steering committee' that will chart the course for TransCanada Gas Services (TCGS). The committee is a key element in carrying out a pledge made in the industry-wide agreement to undertake a review and possible modification of existing codes of conduct, examine the adequacy of separation between TransCanada and Nova's regulated and non-regulated businesses, and carry out discussions aimed at restructuring the netback pool to provide improved pricing and delivery options. Industry sources suggest that this agreement will prevent any repetition of the fierce fight, still before the courts, over the conduct of Pan-Alberta Gas vis-a-vis senior members of a 425-company supply pool. The effects of the agreement on Foothills Pipe Lines decision to withdraw its objection to the Alliance Pipeline project, and the future of competition in the natural gas sector were also reviewed

  9. 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.

  10. Comparative analyses across cattle genders and breeds reveal the pitfalls caused by false positive and lineage-differential copy number variations.

    Science.gov (United States)

    Zhou, Yang; Utsunomiya, Yuri T; Xu, Lingyang; Hay, El Hamidi Abdel; Bickhart, Derek M; Sonstegard, Tad S; Van Tassell, Curtis P; Garcia, Jose Fernando; Liu, George E

    2016-01-01

    We compared CNV region (CNVR) results derived from 1,682 Nellore cattle with equivalent results derived from our previous analysis of Bovine HapMap samples. By comparing CNV segment frequencies between different genders and groups, we identified 9 frequent, false positive CNVRs with a total length of 0.8 Mbp that were likely caused by assembly errors. Although there was a paucity of lineage specific events, we did find one 54 kb deletion on chr5 significantly enriched in Nellore cattle. A few highly frequent CNVRs present in both datasets were detected within genomic regions containing olfactory receptor, ATP-binding cassette, and major histocompatibility complex genes. We further evaluated their impacts on downstream bioinformatics and CNV association analyses. Our results revealed pitfalls caused by false positive and lineage-differential copy number variations and will increase the accuracy of future CNV studies in both taurine and indicine cattle. PMID:27381368

  11. Reaction norms in natural conditions: how does metabolic performance respond to weather variations in a small endotherm facing cold environments?

    Directory of Open Access Journals (Sweden)

    Magali Petit

    Full Text Available Reaction norms reflect an organisms' capacity to adjust its phenotype to the environment and allows for identifying trait values associated with physiological limits. However, reaction norms of physiological parameters are mostly unknown for endotherms living in natural conditions. Black-capped chickadees (Poecile atricapillus increase their metabolic performance during winter acclimatization and are thus good model to measure reaction norms in the wild. We repeatedly measured basal (BMR and summit (Msum metabolism in chickadees to characterize, for the first time in a free-living endotherm, reaction norms of these parameters across the natural range of weather variation. BMR varied between individuals and was weakly and negatively related to minimal temperature. Msum varied with minimal temperature following a Z-shape curve, increasing linearly between 24°C and -10°C, and changed with absolute humidity following a U-shape relationship. These results suggest that thermal exchanges with the environment have minimal effects on maintenance costs, which may be individual-dependent, while thermogenic capacity is responding to body heat loss. Our results suggest also that BMR and Msum respond to different and likely independent constraints.

  12. Analysis and numerical simulation of natural and human-caused low dissolved oxygen in the Minjiang River Estuary.

    Science.gov (United States)

    Zhang, Peng; Pang, Yong; Shi, Chengchun; Wang, Yishu; Xu, Lei; Pan, Hongche; Xie, Rongrong

    2016-01-01

    The Minjiang River, a typical tidal channel in Southeast China, plays an important role in the supply of drinking water, flood control and drought relief, farming and navigation, as well as shipping and other functions. Dissolved oxygen (DO), as a basic living condition for aquatic biota, has been deteriorating in the Minjiang River in recent years. In order to understand how the spatial distribution of DO responds to river discharge, nutrient loading and water temperature, a three-dimensional Environmental Fluid Dynamics Code model was used to simulate water age and the distribution of DO in the Minjiang River. The model presented in this paper was used for water resource and water quality simulations under various physical, chemical, and biological scenarios. Sensitivity simulation results indicated that the three factors had a significant impact on the spatial distribution variation of DO in the Minjiang River. Increased river discharge or split ratio of the North Channel resulted in decreased water age and increased DO. Increased nutrient loading and water temperature caused lower DO. In order to protect coastal environments in the Minjiang River, river discharge should be increased and pollutants of local cities should be reduced during the high temperature and drought period. PMID:27191570

  13. Gamma spectroscopic soil measurements: Spatial variation of concentrations of natural and artificial radionuclides and their correlation with external exposure

    International Nuclear Information System (INIS)

    Within a coherent region of about 1800 km2 (Kreis Steinfurt, North-West Germany) the spatial distribution of natural and artificial radionuclides were determined. The sampling locations were regularly distributed with distances of about 4 km from each other. Each sample was prepared from 36 soil cores (length 20 cm, diameter 46 mm) taken from an area of 100x100 m2 of pasture-land. The soil was air dried, sieved to 2x2 mm and carefully mixed. The measurements were carried out with a high purity coaxial Ge-detector. The measured activities are used to calculate the contribution of artificial and natural radionuclides to the external exposure. Kerma rate factors for infinite homogeneous plane sources in the ground were used, which were calculated by Jacob and Paretzke by the Monte Carlo method. Measurements with a calibrated dose rate meter indicated a good agreement with the calculated values. It is shown, that the spatial variability of the dose rates caused by artificial and natural nuclides respectively is in the same order (about factor 4). For this reason the cesium-distribution pattern is not correlated to the external gamma-ray exposure in the investigated region. (orig.)

  14. Variation of mechanical and thermal properties of the thermoplastics reinforced with natural fibers by electron beam processing

    International Nuclear Information System (INIS)

    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 deg. 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

  15. Enterosgel and natural antioxidants when multimodality therapy is applied to treat malignancy caused by the disaster at Chernobyl Atomic power station

    International Nuclear Information System (INIS)

    They prove that it is appropriate to apply Enterosgel and natural antioxidants in multimodality therapy of patients having malignant tumors caused by radioactive contamination resulted from explosion at Chernobyl APS

  16. 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.

  17. Natural variation in partial resistance to Pseudomonas syringae is controlled by two major QTLs in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Laure Perchepied

    Full Text Available BACKGROUND: Low-level, partial resistance is pre-eminent in natural populations, however, the mechanisms underlying this form of resistance are still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we used the model pathosystem Pseudomonas syringae pv. tomato DC3000 (Pst - Arabidopsis thaliana to study the genetic basis of this form of resistance. Phenotypic analysis of a set of Arabidopsis accessions, based on evaluation of in planta pathogen growth revealed extensive quantitative variation for partial resistance to Pst. It allowed choosing a recombinant inbred line (RIL population derived from a cross between the accessions Bayreuth and Shahdara for quantitative genetic analysis. Experiments performed under two different environmental conditions led to the detection of two major and two minor quantitative trait loci (QTLs governing partial resistance to Pst and called PRP-Ps1 to PRP-Ps4. The two major QTLs, PRP-Ps1 and PRP-Ps2, were confirmed in near isogenic lines (NILs, following the heterogeneous inbred families (HIFs strategy. Analysis of marker gene expression using these HIFs indicated a negative correlation between the induced amount of transcripts of SA-dependent genes PR1, ICS and PR5, and the in planta bacterial growth in the HIF segregating at PRP-Ps2 locus, suggesting an implication of PRP-Ps2 in the activation of SA dependent responses. CONCLUSIONS/SIGNIFICANCE: These results show that variation in partial resistance to Pst in Arabidopsis is governed by relatively few loci, and the validation of two major loci opens the way for their fine mapping and their cloning, which will improve our understanding of the molecular mechanisms underlying partial resistance.

  18. The Genetic Basis of Natural Variation in Seed Size and Seed Number and Their Trade-Off Using Arabidopsis thaliana MAGIC Lines

    OpenAIRE

    Gnan, Sebastian; Priest, Anne; Kover, Paula X.

    2014-01-01

    Offspring number and size are key traits determining an individual’s fitness and a crop’s yield. Yet, extensive natural variation within species is observed for these traits. Such variation is typically explained by trade-offs between fecundity and quality, for which an optimal solution is environmentally dependent. Understanding the genetic basis of seed size and number, as well as any possible genetic constraints preventing the maximization of both, is crucial from both an evolutionary and ...

  19. Natural variation for responsiveness to flg22, flgII-28, and csp22 and Pseudomonas syringae pv. tomato in heirloom tomatoes.

    Directory of Open Access Journals (Sweden)

    Selvakumar Veluchamy

    Full Text Available Tomato (Solanum lycopersicum L. is susceptible to many diseases including bacterial speck caused by Pseudomonas syringae pv. tomato. Bacterial speck disease is a serious problem worldwide in tomato production areas where moist conditions and cool temperatures occur. To enhance breeding of speck resistant fresh-market tomato cultivars we identified a race 0 field isolate, NC-C3, of P. s. pv. tomato in North Carolina and used it to screen a collection of heirloom tomato lines for speck resistance in the field. We observed statistically significant variation among the heirloom tomatoes for their response to P. s. pv. tomato NC-C3 with two lines showing resistance approaching a cultivar that expresses the Pto resistance gene, although none of the heirloom lines have Pto. Using an assay that measures microbe-associated molecular pattern (MAMP-induced production of reactive oxygen species (ROS, we investigated whether the heirloom lines showed differential responsiveness to three bacterial-derived peptide MAMPs: flg22 and flgII-28 (from flagellin and csp22 (from cold shock protein. Significant differences were observed for MAMP responsiveness among the lines, although these differences did not correlate strongly with resistance or susceptibility to bacterial speck disease. The identification of natural variation for MAMP responsiveness opens up the possibility of using a genetic approach to identify the underlying loci and to facilitate breeding of cultivars with enhanced disease resistance. Towards this goal, we discovered that responsiveness to csp22 segregates as a single locus in an F2 population of tomato.

  20. Mechanical stability of a salt cavern submitted to rapid pressure variations: Application to the underground storage of natural gas, compressed air and hydrogen

    International Nuclear Information System (INIS)

    Salt caverns used for the underground storage of large volumes of natural gas are in high demand given the ever-increasing energy needs. The storage of renewable energy is also envisaged in these salt caverns for example, storage of compressed air and hydrogen mass storage. In both cases, salt caverns are more solicited than before because they are subject to rapid injection and withdrawal rates. These new operating modes raise new mechanical problems, illustrated in particular by sloughing, and falling of overhanging blocks at cavern wall. Indeed, to the purely mechanical stress related to changes in gas pressure variations, repeated dozens of degrees Celsius of temperature variation are superimposed; causes in particular during withdrawal, additional tensile stresses whom may lead to fractures at cavern wall; whose evolution could be dangerous. The mechanical behavior of rock salt is known: it is elasto-viscoplastic, nonlinear and highly thermo sensitive. The existing rock salt constitutive laws and failures and damages criteria have been used to analyze the behavior of caverns under the effects of these new loading. The study deals with the thermo mechanics of rocks and helps to analyze the effects of these new operations modes on the structural stability of salt caverns. The approach was to firstly design and validate a thermodynamic model of the behavior of gas in the cavern. This model was used to analyze blowout in gas salt cavern. Then, with the thermo mechanical coupling, to analyze the effects of rapid withdrawal, rapid injection and daily cycles on the structural stability of caverns. At the experimental level, we sought the optimal conditions to the occurrence and the development of cracks on a pastille and a block of rock salt. The creep behavior of rock salt specimens in triaxial extension also was analyzed. (author)

  1. 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.

  2. Genotype-phenotype characteristics and baseline natural history of heritable neuropathies caused by mutations in the MPZ gene.

    Science.gov (United States)

    Sanmaneechai, Oranee; Feely, Shawna; Scherer, Steven S; Herrmann, David N; Burns, Joshua; Muntoni, Francesco; Li, Jun; Siskind, Carly E; Day, John W; Laura, Matilde; Sumner, Charlotte J; Lloyd, Thomas E; Ramchandren, Sindhu; Shy, Rosemary R; Grider, Tiffany; Bacon, Chelsea; Finkel, Richard S; Yum, Sabrina W; Moroni, Isabella; Piscosquito, Giuseppe; Pareyson, Davide; Reilly, Mary M; Shy, Michael E

    2015-11-01

    We aimed to characterize genotype-phenotype correlations and establish baseline clinical data for peripheral neuropathies caused by mutations in the myelin protein zero (MPZ) gene. MPZ mutations are the second leading cause of Charcot-Marie-Tooth disease type 1. Recent research makes clinical trials for patients with MPZ mutations a realistic possibility. However, the clinical severity varies with different mutations and natural history data on progression is sparse. We present cross-sectional data to begin to define the phenotypic spectrum and clinical baseline of patients with these mutations. A cohort of patients with MPZ gene mutations was identified in 13 centres of the Inherited Neuropathies Consortium - Rare Disease Clinical Research Consortium (INC-RDCRC) between 2009 and 2012 and at Wayne State University between 1996 and 2009. Patient phenotypes were quantified by the Charcot-Marie-Tooth disease neuropathy score version 1 or 2 and the Charcot-Marie-Tooth disease paediatric scale outcome instruments. Genetic testing was performed in all patients and/or in first- or second-degree relatives to document mutation in MPZ gene indicating diagnosis of Charcot-Marie-Tooth disease type 1B. There were 103 patients from 71 families with 47 different MPZ mutations with a mean age of 40 years (range 3-84 years). Patients and mutations were separated into infantile, childhood and adult-onset groups. The infantile onset group had higher Charcot-Marie-Tooth disease neuropathy score version 1 or 2 and slower nerve conductions than the other groups, and severity increased with age. Twenty-three patients had no family history of Charcot-Marie-Tooth disease. Sixty-one patients wore foot/ankle orthoses, 19 required walking assistance or support, and 10 required wheelchairs. There was hearing loss in 21 and scoliosis in 17. Forty-two patients did not begin walking until after 15 months of age. Half of the infantile onset patients then required ambulation aids or wheelchairs for

  3. Final technical report for Phenomic Analysis of Natural and Induced Variation in Brachypodium Distachyon DE-SC0001526

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, John P.

    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.

  4. Variation of natural 15N abundance (δ15N) in greenhouse tomato and available nitrogen in soil supplied with cow manure or chemical fertilizers

    International Nuclear Information System (INIS)

    Cow manure or chemical fertilizers applied to greenhouse-grown tomato changed N contents and natural 15N abundance (δ15N) in tomato plants and the δ15N values of available N in soil. Cow manure increased and chemical fertilizers decreased the δ15N values of tomato plants. In the early periods of tomato culture with cow manure, the δ15N values of nitrate nitrogen of soil were higher than those of whole cow manure N, and, thereafter, dropped to δ15N values between those of soil and cow manure. Application of chemical fertilizers to soil immediately raised the δ15N values of ammonium nitrogen in soil but they dropped quickly to δ15N values between those of soil and fertilizers. On the estimation of the soil-derived N, manure-derived N and fertilizer-derived N in tomato plants based on the δ15N values of sources, much caution should be paid concerning the isotopic variation caused by N sources and isotopic fractionation during N transformation in soil. (author)

  5. Natural organic matter-induced alleviation of the phytotoxicity to rice (Oryza sativa L.) caused by copper oxide nanoparticles.

    Science.gov (United States)

    Peng, Cheng; Zhang, Hai; Fang, Huaxiang; Xu, Chen; Huang, Haomin; Wang, Yi; Sun, Lijuan; Yuan, Xiaofeng; Chen, Yingxu; Shi, Jiyan

    2015-09-01

    Natural organic matter (NOM) can interact with engineered nanoparticles (NPs) in the environment and modify their behavior and toxicity to organisms. In the present study, the phytotoxicity of copper oxide (CuO) NPs to rice seedlings in the presence of humic acid as a model NOM was investigated. The results showed that CuO NPs induced the inhibition of root elongation, aberrations in root morphology and ultrastructure, and losses of cell viability and membrane integrity. The adverse effects partly resulted from the generation of reactive oxygen species caused by CuO NPs, which led to lipid peroxidation, mitochondrial dysfunction, and programmed cell death in rice seedlings. However, all the phytotoxicity was alleviated with the addition of humic acid because humic acid coatings on nanoparticle surfaces enhanced electrostatic and steric repulsion between the CuO NPs and the plant cell wall/membrane, reducing contact between NPs and plant and CuO NP-induced oxidative damage to plant cells. The present study's results shed light on the mechanism underlying NP phytotoxicity and highlight the influence of NOM on the bioavailability and toxicity of NPs. PMID:25868010

  6. 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

    OBJECTIVE: Concomitant prescription of more than 1 antipsychotic agent (antipsychotic polypharmacy) in the treatment of schizophrenia is prevalent, although monotherapy is generally recommended. Mortality from natural causes is markedly increased in schizophrenia, and the role of polypharmacy...... remains controversial. The objective was to investigate if antipsychotic polypharmacy is associated with the excess mortality from natural causes among patients with schizophrenia. METHOD: A population-based nested case-control study was conducted using patient data from January 1, 1996, to December 31...... hours) was associated with increased risk of natural death in patients with schizophrenia treated with antipsychotics (OR = 1.78 [95% CI, 1.25-2.52]). CONCLUSIONS: Antipsychotic polypharmacy did not contribute to the excess mortality from natural causes in middle-aged patients with schizophrenia. The...

  7. 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

  8. Features of the short-term position variation of the west Pacific subtropical high during the torrential rain in Yangtze-Huaihe river valley and its possible cause

    Science.gov (United States)

    Guan, Zhaoyong; Yu, Bo; Wang, Lijuan; He, Jielin; Zeng, Gang

    2009-08-01

    By using the NCEP/NCAR daily reanalysis data, CMAP precipitation data , daily precipitation data of 740 stations in China and some remote sensing data, features of the short-term position variation of the west Pacific subtropical high(WPSH) during the torrential rain in Yangtze-Huaihe river valley and its possible cause are analyzed. Results show that the short-term position variation of WPSH is closely associated with the diabatic heating. During the torrential rain period, the apparent heating source and apparent moisture sink are exceptionally strong over Yangtze-Huaihe river valley( on the northwest side of WPSH )and the Bay of Bengal (to the west of WPSH). Based on the complete form of vertical vorticity tendency equation, it is found that the heating field over Yangtze-Huaihe river valley during the torrential rain period, which is in favor of the increase of cyclonic vorticity on the north side of WPSH, is unfavorable to the WPSH moving northward. And the heat source over the Bay of Bengal ,which is in favor of the increase of anti-cyclonic vorticity on the west of WPSH, may induce the westward extension of WPSH.

  9. Impacts of ENSO and ENSO Modoki+A regimes on seasonal precipitation variations and possible underlying causes in the Huai River basin, China

    Science.gov (United States)

    Zhang, Qiang; Wang, Yue; Singh, Vijay P.; Gu, Xihui; Kong, Dongdong; Xiao, Mingzhong

    2016-02-01

    Spatiotemporal patterns of seasonal precipitation changes across the Huai River basin, China, were analyzed, using daily precipitation data from 35 meteorological stations for the period of 1961-2010. Seasonal precipitation changes in related to Eastern Pacific Warming (EPW), Central Pacific Warming (CPW), and Eastern Pacific Cooling (EPC) were investigated. Impacts of canonical ENSO (c-ENSO) and ENSO Modoki+A (EM+A) on seasonal precipitation variations were evaluated. Water vapor transport patterns were also examined to determine the possible mechanisms causing the impacts of ENSO regimes on seasonal precipitation changes. Results indicated that: (1) EPC is the main driver for the increase of spring and autumn precipitation and autumn/spring precipitation tends to decrease during CPW/EPW, respectively. However, EPW and CPW can result in an increase of the summer precipitation amount in the middle and upper basin, and EPC causes an increase of the spring precipitation amount, which may amplify flood risk in the basin; (2) c-ENSO regimes tend to increase the precipitation amount during spring and autumn, especially for the winter precipitation amount. However, c-ENSO and EM+A cause distinctly different impacts on the summer and autumn precipitation: a decrease of summer and autumn precipitation is observed during the EM+A periods while an increase during the c-ENSO periods; (3) In summer and spring, water vapor transport during the c-ENSO periods is more active than during the EM+A periods. Further, water vapor flux is more abundant during the warm episodes of c-ENSO events in spring and summer than during the cold episodes of c-ENSO, and hence higher spring and summer precipitation across the basin. Results of this study may help to understand the causes underlying spatiotemporal patterns of seasonal precipitation and can help in developing measures for the mitigation of floods and droughts hazards in a changing climate.

  10. 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. PMID:21845937

  11. Temporal variations of natural and anthropogenic radionuclides in sea otter skull tissue in the North Pacific Ocean

    International Nuclear Information System (INIS)

    Marine mammals being among the top predators in the food web tend to accumulate organic and inorganic contaminants from the environment. The body burden of contaminants in these species could reflect their foods and thus contaminant levels could serve as proxies on the changes of ecosystem. A pilot study was carried out to investigate the possibility of radionuclide leakage at Amchitka using a suite of sea otter (Enhydra lutris) skulls collected near Amchitka nuclear test-sites before (1950s) and after the testing (1990s), and at Adak, another Aleutian Island, about 300 km from Amchitka, where the potential impact of radionuclide leakage from Amchitka is expected to be negligible. In addition, the naturally occurring and anthropogenic radionuclide content on the sea otter skull was also utilized to investigate if there was any significant ecosystem changes in the environment. Concentration of 210Pb in sea otter bones collected during the 1950s was significantly higher than those collected in the 1990s. We propose that among the various factors that could cause this higher enrichment in 210Pb, changes in the sea otter prey is the most likely one. Comparison of the 137Cs, 90Sr, 239,240Pu concentrations appear not to be significantly higher in sea otter skulls collected in 1990s from Amchitka where the underground tests in 1965-71 than those from Adak, although significant differences were detected among different groups collected at various times

  12. Nature

    OpenAIRE

    Ferretti, Federico; Schmidt Di Friedberg, Marcella

    2012-01-01

    International audience From the ancient times to the present debates on nature and environment, the idea of Nature has been one of the main concepts which interested Geographers. This paper deals with the representations of this idea in the works of thinkers who played a major role in shaping modern Geography, with a special focus on the Mediterranean world. It aims to clarify how Nature was important in defining heuristic strategies of the geographical sciences and their explications of r...

  13. 普光气田地面集输汇管开裂原因分析%Crack Causes of Manifold at a Sour Natural Gas Gathering Project

    Institute of Scientific and Technical Information of China (English)

    张鲁滨; 薛霞; 李俊

    2011-01-01

    The cause and influence factors of crack of manifold were analyzed at a sour natural gas gathering project. Improper welding processes were the root causes. The failure characteristic of cracking was the typical delay cracking.%对普光气田地面集输汇管进行分析后得知,焊接工艺不当是导致输汇管开裂的根本原因,失效特征为延迟开裂.

  14. Flooding in river mouths: human caused or natural events? Five centuries of flooding events in the SW Netherlands, 1500–2000

    OpenAIRE

    A.M.J. de Kraker

    2015-01-01

    This paper looks into flood events of the past 500 years in the SW Netherlands, addressing the issue of what kind of flooding events have occurred and which ones have mainly natural causes and which ones are predominantly human induced. The flood events are classified into two major categories: (a) flood events that were caused during storm surges and (b) flood events which happened during warfare. From both categories a selection of flood events has been made. Each flood ev...

  15. 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

  16. ACCOUNTING OPERATING INCOME CAUSES OF VARIATION: THE IBERIA CASE CAUSAS DE VARIACIÓN DEL RESULTADO CONTABLE ORDINARIO: EL CASO IBERIA

    Directory of Open Access Journals (Sweden)

    Manuel Angel Fernández Gámez

    2009-10-01

    Full Text Available In this article it is intended to develop a model which would help understanding the causes of variation of operational earnings as a result of using external information. To do so, we rely on the study of the effects that lead to a variation of the activity, the total contribution margin, and of other incomes that are independent of activity and fixed costs. Given the close relation between activity and total contribution margin, was analyzed the effect on the operational results that generates variations in each of its components - variable costs per unit and margin rate. With the proposed model, algebraic and discrete type, it is possible to study the operational accounting result since its measurement and accountancy collection are normally done in annual periods, too long for the application of instrumental techniques such as differential equations or partial derivatives, in a way that robustness of the mathematical model was renounced the in favor of its simplicity. En el presente artículo pretendemos desarrollar un modelo que permita comprender las causas de variación del resultado contable ordinario y que resulte de aplicación con información externa. Para ello, nos basamos en el estudio de los efectos que producen sobre el mismo una variación de la actividad, del margen de contribución total, de otros ingresos independientes a la actividad, y de los costes fijos. Dada la estrecha relación existente entre actividad y margen de contribución total, analizamos el efecto sobre el resultado ordinario que producen las variaciones de cada uno de sus componentes – costes variables unitarios y tasa de margen –. Con el modelo planteado, de tipo algebraico y discreto, se facilita el estudio del resultado contable ordinario, pues su medición y captación contable se efectúa normalmente por periodos anuales, demasiado amplios para la aplicación de técnicas instrumentales tales como ecuaciones diferenciales o derivadas parciales, de

  17. Cycle-by-cycle Variations in a Direct Injection Hydrogen Enriched Compressed Natural Gas Engine Employing EGR at Relative Air-Fuel Ratios.

    OpenAIRE

    Olalekan Wasiu Saheed; Rashid A.A.; Baharom Masri

    2014-01-01

    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 whi...

  18. 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

  19. Use of a doxycycline-enrofloxacin-metronidazole combination with/without diminazene diaceturate to treat naturally occurring canine babesiosis caused by Babesia gibsoni

    Directory of Open Access Journals (Sweden)

    Huang Hui-Pi

    2010-04-01

    Full Text Available Abstract Canine babesiosis is an important worldwide, tick-borne disease caused by hemoprotozoan parasites of the genus Babesia. Babesia gibsoni is the predominant species that causes canine babesiosis in Taipei, Taiwan. It is a small pleomorphic intraerythrocytic parasite that can cause erythrocyte destruction and hemolytic anemia. Efficacy of oral administration of a doxycycline-enrofloxacin-metronidazole combination with and without injections of diminazene diaceturate in the management of naturally occurring canine babesiosis caused by B. gibsoni was evaluated retrospectively. The overall efficacy of this combination of doxycycline-enrofloxacin-metronidazole in conjunction with and without administration of diminazene diaceturate was 85.7% and 83.3%, respectively; with a mean recovery time of 24.2 and 23.5 days, respectively. Concomitant use of intramuscular diminazene diaceturate may not improve the efficacy of a doxycycline-enrofloxacin-metronidazole combination in management of canine babesiosis caused by B. gibsoni.

  20. Assessing genetic variation in natural populations of New World screwworm flies: Evidence from microsatellites and mitochondrial DNA

    International Nuclear Information System (INIS)

    Full text: The New World screwworm fly (NWS), Cochliomyia hominivorax (Coquerel 1858, Diptera Calliphoridae), is an obligate ectoparasite that causes myiasis in warm-blooded vertebrates throughout the Neotropical region responsible for significant economic losses to livestock rearing. Because of the substantial economic losses caused by this pest, an international effort eradicated the NWS from endemic areas of North and Central America and is preventing invasions into screwworm-free areas. There have been conflicting reports about the existence of non-interbreeding populations and their possible effects on the control programme. The identification of such populations and an understanding of the genetic variability of target populations is necessary in order to maximize the effectiveness of an eradication programme. We have been using different molecular markers to investigate genetic variability and population structure of C. hominivorax throughout its current geographical distribution in South America in order to address these questions. Mitochondrial DNA (mtDNA) is a marker for studying micro-evolutionary processes in animal populations and can be a suitable marker for estimating the genetic variability within populations. One approach for studying population structure of C. hominivorax population from Uruguay was PCR-RFLP of two specific mitochondrial DNA regions (A+T-rich/12S and cox1/cox 2). The aim of this study was to examine the genetic variability among geographically distinct populations of NWS from Brazil and Uruguay, to have a better scenario of the genetic structure of this species distribution. Nine haplotypes were observed among the populations sampled. The mean nucleotide diversity (π= 2.3%) and the haplotype diversity (Hs= 0.6533) indicated high mtDNA variability in this species. The similarity index (96.7%), the average nucleotide divergence (δ= 0.00055) and the AMOVA results showed no evidence of subpopulation differentiation. In this case

  1. Natural Variation of Cold Deacclimation Correlates with Variation of Cold-Acclimation of the Plastid Antioxidant System in Arabidopsis thaliana Accessions.

    Science.gov (United States)

    Juszczak, Ilona; Cvetkovic, Jelena; Zuther, Ellen; Hincha, Dirk K; Baier, Margarete

    2016-01-01

    Temperature variations impact on the balance between photosynthetic electron transport and electron-consuming assimilation reactions and transiently increase generation of reactive oxygen species (ROS). Previous studies demonstrated that the expression of C-repeat binding factors (CBFs), which activate cold acclimation reactions, respond to chloroplast ROS signals and that cold deacclimation is partly halted for days after the transfer of acclimated plants to optimal growth conditions in four Arabidopsis accessions from cold-continental habitats. We hypothesized that these accessions differ from others in the regulation of the plastid antioxidant system (PAS). In the present study, we compared the expression intensity of the 12 most prominent PAS genes for peroxidases, superoxide dismutase and low molecular weight antioxidant regenerating enzymes in 10 Arabidopsis accessions with regulation of CBF and COR (cold regulated genes) transcript levels and cold-regulated metabolite levels prior to cold, after 2 week long cold acclimation and during the first 3 days of deacclimation. In the accessions with prolonged activation of cold responses, by trend, weaker induction of various cold-inducible PAS genes and stronger decreases in the expression of negatively cold-regulated PAS genes were observed. Low PAS gene expression delayed the post-cold decrease in H2O2 levels after transfer of the plants from cold to optimal growth conditions. We conclude that weaker expression of various PAS genes in the cold is an adapted strategy of the Arabidopsis accessions N14, N13, Ms-0, and Kas-1 to avoid full inactivation of cold-responses in the first days after the end of the cold period. PMID:27014325

  2. [Variation in the timing of spawning of the Black Sea brown trout Salmo trutta labrax Pallas under artificial and natural conditions].

    Science.gov (United States)

    Makhrov, A A; Artamonova, V S; Sumarokov, V S; Pashkov, A N; Reshetnikov, S I; Ganchenko, M V; Kulian, S A

    2011-01-01

    Analysis of the maturation and spawning times of the Black Sea brown trout bred at the fish-farming plants and inhabiting natural waterways of the Northwestern Caucasus has demonstrated a considerable variation depending on environmental conditions, first and foremost, temperature. This fact, as well as the analysis of literature data, suggests that the duration and timing of the spawning season cannot be used as self-sufficient criteria for identifying species of the genus Salmo. PMID:21506392

  3. The Effect of Natural Variation at Ppd-H1 and HvELF3 on Responses to Osmotic Stress in Barley (Hordeum Vulgare)

    OpenAIRE

    Haile, Ermias Habte

    2013-01-01

    The circadian clock is an important timing system that, in part, controls stress adaptation in Arabidopsis thaliana. In the model crop barley, the clock orthologs Ppd-H1 and HvELF3 are important regulators of photoperiod response and flowering. However, little is known about additional effects of the clock on plant performance and stress adaptation in barley. Therefore, the objectives of this study were i) to analyse the effects of natural variation at the barley photoperiod response and cloc...

  4. Natural gas price uncertainty and the cost-effectiveness of hedging against low hydropower revenues caused by drought

    Science.gov (United States)

    Kern, Jordan D.; Characklis, Gregory W.; Foster, Benjamin T.

    2015-04-01

    Prolonged periods of low reservoir inflows (droughts) significantly reduce a hydropower producer's ability to generate both electricity and revenues. Given the capital intensive nature of the electric power industry, this can impact hydropower producers' ability to pay down outstanding debt, leading to credit rating downgrades, higher interests rates on new debt, and ultimately, greater infrastructure costs. One potential tool for reducing the financial exposure of hydropower producers to drought is hydrologic index insurance, in particular, contracts structured to payout when streamflows drop below a specified level. An ongoing challenge in developing this type of insurance, however, is minimizing contracts' "basis risk," that is, the degree to which contract payouts deviate in timing and/or amount from actual damages experienced by policyholders. In this paper, we show that consideration of year-to-year changes in the value of hydropower (i.e., the cost of replacing it with an alternative energy source during droughts) is critical to reducing contract basis risk. In particular, we find that volatility in the price of natural gas, a key driver of peak electricity prices, can significantly degrade the performance of index insurance unless contracts are designed to explicitly consider natural gas prices when determining payouts. Results show that a combined index whose value is derived from both seasonal streamflows and the spot price of natural gas yields contracts that exhibit both lower basis risk and greater effectiveness in terms of reducing financial exposure.

  5. The variation of chemical characteristics of PM2.5 and PM10 and formation causes during two haze pollution events in urban Beijing, China

    Science.gov (United States)

    Gao, Jiajia; Tian, Hezhong; Cheng, Ke; Lu, Long; Zheng, Mei; Wang, Shuxiao; Hao, Jiming; Wang, Kun; Hua, Shenbing; Zhu, Chuanyong; Wang, Yong

    2015-04-01

    Airborne particles in urban Beijing during haze days and normal days were collected and analyzed in the autumn and winter seasons to reveal the chemical characteristics variations of air pollution. The air quality in haze days was substantially worse than that in normal days. Both the relatively low wind speed and high relative humidity were in favor of the accumulation of pollution species and new formation of secondary PM2.5 in the atmosphere. Elevated concentrations of elements and water-soluble inorganic ions were found on haze days for both PM10 and PM2.5. Particularly, the crustal element, such as Fe, in both PM10 and PM2.5 were substantially higher in autumn normal days and winter haze days than those in autumn haze days and winter normal days, indicating that the abundance of Fe in autumn haze days mainly be originated from crustal dust while in winter haze days it might be primarily emitted from anthropogenic sources (iron and steel smelting) instead of road dust. Secondary ion species (SO42-, NO3-, NH4+) in particles were generated much more during haze episodes, and contributed a higher proportion in PM2.5 than in PM10 during the two sampling periods. Moreover, HYSPLIT model was used to explain the possible transport of airborne particles from distant sources. By comparing with south-type trajectory, west-type trajectory entrained larger amounts of primary crustal pollutants, while, south-type trajectory was comprised of a higher mass of anthropogenic pollution species. The results of back trajectory analysis indicated that the elevated concentration of aerosol and its chemical components during haze days might be caused by the integrated effects of accumulation under stagnant meteorological condition and the transport emissions of pollutants from anthropogenic sources surrounding Beijing city.

  6. 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

  7. 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.

  8. 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...

  9. 论我国农村居民“因灾返贫”%Research on the Rural Residents Returning to Poverty Caused by Natural Disasters

    Institute of Scientific and Technical Information of China (English)

    彭腾

    2013-01-01

    The relationships between natural disasters and rural poverty rates is a positive corelation. There is still poverty in the country-side, and people returning to poverty due to natural disasters is worsening at the same time. This mainly originates from the regular natural disasters,insufficient capacity of natural disasters resistance and the shortage of the disaster relief. In order to avoid the rural residents to return to the poverty caused by the natural disasters, we must strengthen the work of natural environment protection and restoration for disaster prevention through the ecological migration and urbanization to ward off disaster, to strengthen the infrastructure for disaster resistance and to perfect the system of the agricultural insurance relief towards disaster relief.%自然灾害与农村贫困发生率呈正向关系。我国现阶段的农村居民因灾返贫问题比较严重,主要源于自然灾害频发、抗灾能力较弱和灾害救助不足。要避免农村居民因灾返贫,必须通过保护与修复自然环境来防灾,生态移民及城镇化来避灾,加强基础设施建设来抗灾和完善农业保险救助体系来救灾。

  10. 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

    It is known that, for parchment and leather tanned with condensed types of vegetable tannins stored under acid conditions, chemical deterioration may lead to a transformation of the collagen into a gelatine-like substance that may dissolve in water even at ambient temperature. In a previous study...... by microscopic examinations, as well as by hydrothermal shrinkage activity measurements. Examinations of degraded historical parchment documents and leather objects show that the gelatinisation may take place as part of the natural deterioration. However, especially parchment documents which have...

  11. Host suitability of soybean and corn genotypes to the root lesion caused by nematode under natural infestation conditions

    OpenAIRE

    Anderli Divina Ferreira Rios; Mara Rúbia da Rocha; Alan Soares Machado; Kássia Aparecida Garcia Barbosa Ávila; Renato Andrade Teixeira; Leonardo de Castro Santos; Lilian Rosana Silva Rabelo

    2016-01-01

    ABSTRACT: Among the nematode management strategies, genetic resistance is one of the most appropriate and desirable. However, resistant soybean and corn genotypes resistant to Pratylenchus brachyurus are not available up to the moment. The objective of this study was to evaluate the host suitability of 50 soybean and 38 corn genotypes to P. brachyurus under natural infestation. Soybean genotypes BRSGO Chapadões, BRSGO Paraíso, M-Soy 7211 RR, M-Soy 8008 RR, Emgopa 313 RR, M-Soy 8411, BRSGO Jul...

  12. 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.

  13. 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.

  14. Seasonal variation in cause-specific mortality: are there high-risk groups? 25-year follow-up of civil servants from the first Whitehall study

    NARCIS (Netherlands)

    C.T.M. van Rossum (Caroline); M.J. Shipley; H. Hemingway; D.E. Grobbee (Diederick); J.P. Mackenbach (Johan); M.G. Marmot

    2001-01-01

    textabstractOBJECTIVES: To determine the seasonal effect on all-cause and cause-specific mortality and to identify high-risk groups. METHODS: A 25-year follow-up of 19,019 male civil servants aged 40-69 years. RESULTS: All-cause mortality was seasonal (ratio of highest mortality ra

  15. Host suitability of soybean and corn genotypes to the root lesion caused by nematode under natural infestation conditions

    Directory of Open Access Journals (Sweden)

    Anderli Divina Ferreira Rios

    2016-04-01

    Full Text Available ABSTRACT: Among the nematode management strategies, genetic resistance is one of the most appropriate and desirable. However, resistant soybean and corn genotypes resistant to Pratylenchus brachyurus are not available up to the moment. The objective of this study was to evaluate the host suitability of 50 soybean and 38 corn genotypes to P. brachyurus under natural infestation. Soybean genotypes BRSGO Chapadões, BRSGO Paraíso, M-Soy 7211 RR, M-Soy 8008 RR, Emgopa 313 RR, M-Soy 8411, BRSGO Juliana RR, Emgopa 316 RR, BRSGO Luziânia RR and TMG 103 RR, and corn genotype Agromem 30A06 reduced the nematode population during the evaluation period.

  16. Genome-wide analysis of ZmDREB genes and their association with natural variation in drought tolerance at seedling stage of Zea mays L.

    Directory of Open Access Journals (Sweden)

    Shengxue Liu

    Full Text Available The worldwide production of maize (Zea mays L. is frequently impacted by water scarcity and as a result, increased drought tolerance is a priority target in maize breeding programs. While DREB transcription factors have been demonstrated to play a central role in desiccation tolerance, whether or not natural sequence variations in these genes are associated with the phenotypic variability of this trait is largely unknown. In the present study, eighteen ZmDREB genes present in the maize B73 genome were cloned and systematically analyzed to determine their phylogenetic relationship, synteny with rice, maize and sorghum genomes; pattern of drought-responsive gene expression, and protein transactivation activity. Importantly, the association between the nucleic acid variation of each ZmDREB gene with drought tolerance was evaluated using a diverse population of maize consisting of 368 varieties from tropical and temperate regions. A significant association between the genetic variation of ZmDREB2.7 and drought tolerance at seedling stage was identified. Further analysis found that the DNA polymorphisms in the promoter region of ZmDREB2.7, but not the protein coding region itself, was associated with different levels of drought tolerance among maize varieties, likely due to distinct patterns of gene expression in response to drought stress. In vitro, protein-DNA binding assay demonstrated that ZmDREB2.7 protein could specifically interact with the target DNA sequences. The transgenic Arabidopsis overexpressing ZmDREB2.7 displayed enhanced tolerance to drought stress. Moreover, a favorable allele of ZmDREB2.7, identified in the drought-tolerant maize varieties, was effective in imparting plant tolerance to drought stress. Based upon these findings, we conclude that natural variation in the promoter of ZmDREB2.7 contributes to maize drought tolerance, and that the gene and its favorable allele may be an important genetic resource for the genetic

  17. Morphometric and allozyme variation in natural populations and cultured strains of the Nile tilapia Oreochromis niloticus niloticus (Teleostei, Cichlidae)

    OpenAIRE

    Vreven, E.J.; Adépo-Gourène, Béatrice; Agnèse, Jean-François; Teugels, G.G.

    1998-01-01

    Les variations morphométriques et allozymiques de neuf populations naturelle de #Oreochromis niloticus$ et de trois populations d'élevage ont été étudiées. Des différences dans la morphologie et les allozymes ont été observées entre les populations naturelles d'Afrique de l'Ouest et du Nil. Bien que toutes ces populations soient rangées dans la sous-espèce #O. n. niloticus$, la population du Nil est plus proche de la population du lac Edward qui appartient à la sous-espèce #O. n. eduardianus$...

  18. 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…

  19. What does variation on household survey methods reveal about the nature of measurement errors in consumption estimates?

    OpenAIRE

    Gibson, John; BEEGLE, KATHLEEN; Weerdt, Joachim De; Friedman, Jed

    2015-01-01

    We randomly assigned eight different consumption surveys to obtain evidence on the nature of measurement errors in estimates of household consumption. Regressions using data from more error-prone designs are compared with results from a “gold standard” survey. Measurement errors appear to have a mean-reverting negative correlation with true consumption, especially for food and especially for rural households.

  20. Updated estimates of the proportion of childhood leukaemia incidence in Great Britain that may be caused by natural background ionising radiation

    International Nuclear Information System (INIS)

    The aetiology of childhood leukaemia remains generally unknown, although exposure to moderate and high levels of ionising radiation, such as was experienced during the atomic bombings of Japan or from radiotherapy, is an established cause. Risk models based primarily upon studies of the Japanese A-bomb survivors imply that low-level exposure to ionising radiation, including to ubiquitous natural background radiation, also raises the risk of childhood leukaemia. In a recent paper (Wakeford et al 2009 Leukaemia 23 770-6) we estimated the proportion of childhood leukaemia incidence in Great Britain attributable to natural background radiation to be about 20%. In this paper we employ the two sets of published leukaemia risk models used previously, but use recently published revised estimates of natural background radiation doses received by the red bone marrow of British children to update the previous results. Using the newer dosimetry we calculate that the best estimate of the proportion of cases of childhood leukaemia in Great Britain predicted to be attributable to this source of exposure is 15-20%, although the uncertainty associated with certain stages in the calculation (e.g. the nature of the transfer of risk between populations and the pertinent dose received from naturally occurring alpha-particle-emitting radionuclides) is significant. The slightly lower attributable proportions compared with those previously derived by Wakeford et al (Leukaemia 2009 23 770-6) are largely due to the lower doses (and in particular lower high LET doses) for the first year of life.

  1. Updated estimates of the proportion of childhood leukaemia incidence in Great Britain that may be caused by natural background ionising radiation

    Energy Technology Data Exchange (ETDEWEB)

    Little, Mark P [Department of Epidemiology and Public Health, Imperial College, London W2 1PG (United Kingdom); Wakeford, Richard [Dalton Nuclear Institute, University of Manchester, Pariser Building-G Floor, PO Box 88, Sackville Street, Manchester M60 1QD (United Kingdom); Kendall, Gerald M [Childhood Cancer Research Group, Richards Building, University of Oxford, Old Road Campus, Oxford OX3 7LG (United Kingdom)], E-mail: mark.little@imperial.ac.uk

    2009-12-01

    The aetiology of childhood leukaemia remains generally unknown, although exposure to moderate and high levels of ionising radiation, such as was experienced during the atomic bombings of Japan or from radiotherapy, is an established cause. Risk models based primarily upon studies of the Japanese A-bomb survivors imply that low-level exposure to ionising radiation, including to ubiquitous natural background radiation, also raises the risk of childhood leukaemia. In a recent paper (Wakeford et al 2009 Leukaemia 23 770-6) we estimated the proportion of childhood leukaemia incidence in Great Britain attributable to natural background radiation to be about 20%. In this paper we employ the two sets of published leukaemia risk models used previously, but use recently published revised estimates of natural background radiation doses received by the red bone marrow of British children to update the previous results. Using the newer dosimetry we calculate that the best estimate of the proportion of cases of childhood leukaemia in Great Britain predicted to be attributable to this source of exposure is 15-20%, although the uncertainty associated with certain stages in the calculation (e.g. the nature of the transfer of risk between populations and the pertinent dose received from naturally occurring alpha-particle-emitting radionuclides) is significant. The slightly lower attributable proportions compared with those previously derived by Wakeford et al (Leukaemia 2009 23 770-6) are largely due to the lower doses (and in particular lower high LET doses) for the first year of life.

  2. 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.

  3. 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. PMID:26911957

  4. [Incapacity to undertaking the essential marital duties due to causes of psychic nature. The forensic-psychiatric point of view].

    Science.gov (United States)

    Drogowski, Marian

    2010-01-01

    Since at least 20 years, most of the legal proceedings of marital incapacity are carried on by the church tribunals mainly of no 3 canon 1095 new law code, that is of mental incapacity to undertaking and performing the essential marital duties. Very often the legal proceedings are very difficult and the canonical lawyers need the forensic psychiatric or psychological opinions. The aim of this paper is to give the forensic psychiatrists and psychologists the essential knowledge connected with the new regulations listed in canon 1095 no 3 of the actual canon law code. According to the opinions of the notable canonical lawyers the author describes the legal and marital prerequisites for valid marriage, the ability for undertaking and performing the essential marital duties and the mental reasons for marital incapacity. The author points out several psychiatric reasons underlying the mental incapacity for undertaking and performing essential marital duties: personality disorders and alcoholism which preclude adequate interpersonal relations and sexually related personality disorders which preclude the exclusiveness and natural consumption of the marital agreement. At the end the author points out the conditions which should have good forensic opinion. PMID:20919500

  5. Causes of Infertility

    Science.gov (United States)

    Infertility Causes of male infertility Causes of female infertility Infertility is clinically defined as the inability to conceive naturally after one year of frequent, unprotected intercourse. Approximately 7. ...

  6. Protective Effect of Natural Honey, Urtica diocia and Their Mixture against Oxidative Stress Caused by Chronic Ethanol Consumption.

    Directory of Open Access Journals (Sweden)

    G.M.F Edrees*, F.G.EL-Said and E.T.Salem

    2007-06-01

    Full Text Available Background: There is increasing implicating oxidative stress in the pathogenesis of chronic pancreatitis. The aim of this study is to investigate affect alcohol addiction and role of some protecting agent. Material and methods: Forty eight rats (Rattus norvigicus were divided into 8 groups. Honey (2.5 g /kg b.w, Urtica dioica (250 mg/kg and Alcohol orally administered at dose (20% exceeds by 2.5% weekly. Results: Ethanol feeding results in increasing serum glucose, total lipids, cholesterol, Low Density Lipoprotein (LDL, triglycerides, urea, liver Glucose-6-Phosphatase (G6Pase, pancreas and liver Malondialdehyde (MDA, Protein Carbonyl (PC. While a decrease were noted in serum insulin, High Density Lipoprotein (HDL, total Protein, Na, K, Ca, Mg, Cu, liver glycogen, pancreas and liver Glucose-6-Phosphate Dehydrogenase (G6PD, Glutathione-S-Transferase (GST, Reduced Glutathione (GSH, Catalase (CAT, Superoxide Dismutase (SOD. Conclusion: Administration of honey, urtica or both with alcohol prevent to great extent the lesions caused by only chronic alcohol administration. Consequently, honey and urtica administration are useful to minimize the hazardous effects resulting from ethanol abuse

  7. Variation in the response of the invasive species Potamopyrgus antipodarum (Smith) to natural (cyanobacterial toxin) and anthropogenic (herbicide atrazine) stressors

    International Nuclear Information System (INIS)

    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

  8. Tree ring reconstruction of summer temperature variations over the past 159 years in Wolong National Natural Reserve, western Sichuan, China

    OpenAIRE

    LI Zong-Shan; Liu, Guo-Hua; ZHANG Qi-Bing; HU Chan-Juan; LUO Shu-Zheng; LIU Xing-Liang; He, Fei

    2010-01-01

    Aims Improved understanding of tree growth responses to climate is needed to model and predict forest ecosystem responses to current and future climatic variability. Coniferous forests in Wolong National Natural Reserve occupy broad elevational ranges with varied geology and topography and thus have great potential for dendroclimatological studies. However, little is known about the growth-climate relationships in this region compared with the nearby Tibetan Plateau. Our objective was to dete...

  9. 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. PMID:26380693

  10. Reaction Norms in Natural Conditions: How Does Metabolic Performance Respond to Weather Variations in a Small Endotherm Facing Cold Environments?

    OpenAIRE

    Petit, Magali; Vézina, François

    2014-01-01

    Reaction norms reflect an organisms' capacity to adjust its phenotype to the environment and allows for identifying trait values associated with physiological limits. However, reaction norms of physiological parameters are mostly unknown for endotherms living in natural conditions. Black-capped chickadees (Poecile atricapillus) increase their metabolic performance during winter acclimatization and are thus good model to measure reaction norms in the wild. We repeatedly measured basal (BMR) an...

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

    OpenAIRE

    Vinod Prasad Khanduri; Sharma, C. M.; Kumar, K. S.; S. K. Ghildiyal

    2013-01-01

    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. T...

  12. Molecular phylogeny of mangroves IV. nature and extent of intra-specific genetic variation and species diversity in mangroves

    International Nuclear Information System (INIS)

    Mangroves occupy estuarine ecosystems in the tropical regions of the world. Despite their highly productive nature and the protective roles they play in the coastal region, the ecosystem as a whole is under severe threat due to various climatic and anthropogenic factors. Therefore, the need for conservation of mangroves is widely emphasised. However, information on existing genetic diversity based on which a strategy for genetic conservation is to be drawn is not available for mangroves. This is primarily because conventional genetic analysis is difficult in these species for various reasons. Therefore, as an aid to our on-going conservation programme, efforts were made to assess the nature and extent of diversity in a number of mangrove species of the Indian coast using molecular markers. The nature and extent of intra-population diversity in sixteen mangrove species and detailed analysis of inter-population genetic polymorphism in four species, Acanthus ilicifolius, Excoecaria agallocha, Avicennia spp and Rhizophora (species and hybrid), is reported in the present communication. (author)

  13. Precipitation ensembles conforming to natural variations derived from a regional climate model using a new bias correction scheme

    Science.gov (United States)

    Kim, Kue Bum; Kwon, Hyun-Han; Han, Dawei

    2016-05-01

    This study presents a novel bias correction scheme for regional climate model (RCM) precipitation ensembles. A primary advantage of using model ensembles for climate change impact studies is that the uncertainties associated with the systematic error can be quantified through the ensemble spread. Currently, however, most of the conventional bias correction methods adjust all the ensemble members to one reference observation. As a result, the ensemble spread is degraded during bias correction. Since the observation is only one case of many possible realizations due to the climate natural variability, a successful bias correction scheme should preserve the ensemble spread within the bounds of its natural variability (i.e. sampling uncertainty). To demonstrate a new bias correction scheme conforming to RCM precipitation ensembles, an application to the Thorverton catchment in the south-west of England is presented. For the ensemble, 11 members from the Hadley Centre Regional Climate Model (HadRM3-PPE) data are used and monthly bias correction has been done for the baseline time period from 1961 to 1990. In the typical conventional method, monthly mean precipitation of each of the ensemble members is nearly identical to the observation, i.e. the ensemble spread is removed. In contrast, the proposed method corrects the bias while maintaining the ensemble spread within the natural variability of the observations.

  14. Precipitation ensembles conforming to natural variations derived from Regional Climate Model using a new bias correction scheme

    Science.gov (United States)

    Kim, K. B.; Kwon, H.-H.; Han, D.

    2015-10-01

    This study presents a novel bias correction scheme for Regional Climate Model (RCM) precipitation ensembles. A primary advantage of using model ensembles for climate change impact studies is that the uncertainties associated with the systematic error can be quantified through the ensemble spread. Currently, however, most of the conventional bias correction methods adjust all the ensemble members to one reference observation. As a result, the ensemble spread is degraded during bias correction. Since the observation is only one case of many possible realizations due to the climate natural variability, bias correction scheme should preserve ensemble spread within the bounds of natural variability (i.e. sampling uncertainty). To demonstrate the proposed methodology, an application to the Thorverton catchment in the southwest of England is presented. For the ensemble, 11-members from the Hadley Centre Regional Climate Model (HadRM3-PPE) Data are used and monthly bias correction has been done for the baseline time period from 1961 to 1990. In the typical conventional method, monthly mean precipitation of each of the ensemble members are nearly identical to the observation, i.e. the ensemble spread is removed. In contrast, the proposed method corrects the biases while maintain ensemble spread within the natural variability of observations.

  15. Precipitation ensembles conforming to natural variations derived from Regional Climate Model using a new bias correction scheme

    Directory of Open Access Journals (Sweden)

    K. B. Kim

    2015-10-01

    Full Text Available This study presents a novel bias correction scheme for Regional Climate Model (RCM precipitation ensembles. A primary advantage of using model ensembles for climate change impact studies is that the uncertainties associated with the systematic error can be quantified through the ensemble spread. Currently, however, most of the conventional bias correction methods adjust all the ensemble members to one reference observation. As a result, the ensemble spread is degraded during bias correction. Since the observation is only one case of many possible realizations due to the climate natural variability, bias correction scheme should preserve ensemble spread within the bounds of natural variability (i.e. sampling uncertainty. To demonstrate the proposed methodology, an application to the Thorverton catchment in the southwest of England is presented. For the ensemble, 11-members from the Hadley Centre Regional Climate Model (HadRM3-PPE Data are used and monthly bias correction has been done for the baseline time period from 1961 to 1990. In the typical conventional method, monthly mean precipitation of each of the ensemble members are nearly identical to the observation, i.e. the ensemble spread is removed. In contrast, the proposed method corrects the biases while maintain ensemble spread within the natural variability of observations.

  16. A physically-based method for predicting peak discharge of floods caused by failure of natural and constructed earthen dams

    Science.gov (United States)

    Walder, J.S.; O'Connor, J. E.; Costa, J.E.

    1997-01-01

    We analyse a simple, physically-based model of breach formation in natural and constructed earthen dams to elucidate the principal factors controlling the flood hydrograph at the breach. Formation of the breach, which is assumed trapezoidal in cross-section, is parameterized by the mean rate of downcutting, k, the value of which is constrained by observations. A dimensionless formulation of the model leads to the prediction that the breach hydrograph depends upon lake shape, the ratio r of breach width to depth, the side slope ?? of the breach, and the parameter ?? = (V.D3)(k/???gD), where V = lake volume, D = lake depth, and g is the acceleration due to gravity. Calculations show that peak discharge Qp depends weakly on lake shape r and ??, but strongly on ??, which is the product of a dimensionless lake volume and a dimensionless erosion rate. Qp(??) takes asymptotically distinct forms depending on whether flood hydrograph at the breach. Formation of the breach, which is assumed trapezoidal in cross-section, is parameterized by the mean rate of downcutting, k, the value of which is constrained by observations. A dimensionless formulation of the model leads to the prediction that the breach hydrograph depends upon lake shape, the ratio r of breach width to depth, the side slope ?? of the breach, and the parameter ?? = (V/D3)(k/???gD), where V = lake volume, D = lake depth, and g is the acceleration due to gravity. Calculations show that peak discharge Qp depends weakly on lake shape r and ??, but strongly on ??, which is the product of a dimensionless lake volume and a dimensionless erosion rate. Qp(??) takes asymptotically distinct forms depending on whether ?????1 or ?????1. Theoretical predictions agree well with data from dam failures for which k could be reasonably estimated. The analysis provides a rapid and in many cases graphical way to estimate plausible values of Qp at the breach.

  17. 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.

  18. The dose exposure of the environmental population caused by natural Ra-226 and Pb-210 and released from uraniferous heaps

    International Nuclear Information System (INIS)

    The concentrations of Ra-226 and Pb-210 in samples of air, soil, surface water, and foods from Wittichen agree well with the average environmental concentrations. Higher values are found in soil samples from old heaps, in surface waters being in contact with these heaps and in grass and mushrooms grown on such heaps. On the supposition that only locally produced foods are used for annual intake, an annual activity intake of 925 pCi Ra-226 and 2 772 pCi Pb-210 is determined. These annual intakes are higher by a factor of 2.1 compared with the maximum permissible intakes given by the Radiation Protection Ordinance. The transfer factors determined in other parts of the Black Forest are in accordance with these values. The Pb-210 concentrations in grass and leafy vegetables are pretty high; the contamination of this kind of samples is caused by the deposition of Pb-210 from ground level air. Using Pb-210 concentrations in air and plants, one achieves deposition velocities and effective half-lives, respectively, which agree very well with values already known. For depth profiles of Ra-226, Pb-210, and Po-210 in soil of a meadow and a heap, the interpretation of the results achieved is difficult, since the processes of contamination and decontamination are very complicated. Still after more than one and a half century the transport of Ra-226 from the uraniferous material to deeper soil layers is negligible. The transport of Pb-210 and Po-210 is much faster. (orig./HP)

  19. 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.

  20. Natural Variation in Tomato Reveals Differences in the Recognition of AvrPto and AvrPtoB Effectors from Pseudomonas syringae.

    Science.gov (United States)

    Kraus, Christine M; Munkvold, Kathy R; Martin, Gregory B

    2016-05-01

    The Pto protein kinase from Solanum pimpinellifolium interacts with Pseudomonas syringae effectors AvrPto or AvrPtoB to activate effector-triggered immunity. The previously solved crystal structures of the AvrPto-Pto and AvrPtoB-Pto complexes revealed that Pto binds each effector through both a shared and a unique interface. Here we use natural variation in wild species of tomato to further investigate Pto recognition of these two effectors. One species, Solanum chmielewskii, was found to have many accessions that recognize only AvrPtoB. The Pto ortholog from one of these accessions was responsible for recognition of AvrPtoB and it differed from Solanum pimpinellifolium Pto by only 14 amino acids, including two in the AvrPto-specific interface, glutamate-49/glycine-51. Converting these two residues to those in Pto (histidine-49/valine-51) did not restore recognition of AvrPto. Subsequent experiments revealed that a single substitution of a histidine-to-aspartate at position 193 in Pto, which is not near the AvrPto-specific interface, was sufficient for conferring recognition of AvrPto in plant cells. The reciprocal substitution of aspartate-to-histidine-193 in Pto abolished AvrPto recognition, confirming the importance of this residue. Our results reveal new aspects about effector recognition by Pto and demonstrate the value of using natural variation to understand the interaction between resistance proteins and pathogen effectors. PMID:26993968

  1. 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.

  2. 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.

  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)

    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 (< 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. Spatio-temporal variation in the hydrochemistry of Tawa River, Central India: effect of natural and anthropogenic factors.

    Science.gov (United States)

    Mehto, Ashwini; Chakrapani, G J

    2013-12-01

    Tawa River is the biggest left bank tributary of the Narmada, the largest west-flowing river of the Indian peninsula. Central India enjoys a tropical climate, is highly urbanized, and the river flow is mostly controlled by monsoon; a large part of the population depend on rivers for their livelihood. Spatial and temporal variations in the hydrochemistry of the Tawa River were studied based on seasonal sampling along the course of the river and its tributaries. The study is important because not much data exist on small size rivers and the river processes spell out correctly in smaller basins. The monsoon season accounts for more than 70% of river water flow. The basin is characterized by silicate lithology; however, water chemistry is controlled by carbonate-rich soils and other weathering products of the silicate rocks, as indicated by the high (Ca + Mg)/(Na + K) ratios (>3.8). The values of the Na-normalized ratios of Ca(2+), Mg(2+), and HCO₃(-) suggest that both the carbonate and silicate lithology contribute to the hydrochemistry. On average, 42% of HCO₃(-) in the Tawa River water is contributed by silicate weathering and 58% from carbonate lithology. The water remains undersaturated with respect to calcite during the monsoon and post-monsoon seasons and supersaturated during the pre-monsoon season. A significant influence of mining in the basin and other industrial units is observed in water chemical composition. PMID:23761165

  6. Mitochondrial genetic variations in natural house fly (Musca domestica L.) populations from the western and southern parts of Turkey.

    Science.gov (United States)

    Doğaç, Ersin

    2016-09-01

    The house fly Musca domestica Linnaeus (Diptera) is one of the most studied species that is globally distributed and well known to everyone. In order to ensure baseline knowledge for the genetic resources of the species, genetic variation in M. domestica populations from western and southern parts of Turkey was investigated using nucleotide sequence analysis of 348 base pairs (bp) in the mitochondrial cytochrome oxidase subunit I gene (COI). Samples of 192 individuals were collected from 16 localities of Turkey. There were 10 variable sites defining two haplotypes of COI in this species. There was no difference in geographical distribution frequency between the two regions of Turkey. Overall, haplotype diversity (h) was low, ranging from 0 to 0.5606 with the average overall value of 0.178 ± 0.04 and nucleotide diversity (π), ranged from 0 to 0.0056 with the overall mean of 0.0016. Analysis of molecular variance (AMOVA) indicated that genetic differentiation within individuals and populations was low and significant (p fly populations in Turkey are grouped with the Palearctic region, which is the most probable place for the origin of this species. PMID:26369566

  7. Measuring the immune system of the three-spined stickleback - investigating natural variation by quantifying immune expression in the laboratory and the wild.

    Science.gov (United States)

    Robertson, Shaun; Bradley, Janette E; MacColl, Andrew D C

    2016-05-01

    Current understanding of the immune system comes primarily from laboratory-based studies. There has been substantial interest in examining how it functions in the wild, but studies have been limited by a lack of appropriate assays and study species. The three-spined stickleback (Gasterosteus aculeatus L.) provides an ideal system in which to advance the study of wild immunology, but requires the development of suitable immune assays. We demonstrate that meaningful variation in the immune response of stickleback can be measured using real-time PCR to quantify the expression of eight genes, representing the innate response and Th1-, Th2- and Treg-type adaptive responses. Assays are validated by comparing the immune expression profiles of wild and laboratory-raised stickleback, and by examining variation across populations on North Uist, Scotland. We also compare the immune response potential of laboratory-raised individuals from two Icelandic populations by stimulating cells in culture. Immune profiles of wild fish differed from laboratory-raised fish from the same parental population, with immune expression patterns in the wild converging relative to those in the laboratory. Innate measures differed between wild populations, whilst the adaptive response was associated with variation in age, relative size of fish, reproductive status and S. solidus infection levels. Laboratory-raised individuals from different populations showed markedly different innate immune response potential. The ability to combine studies in the laboratory and in the wild underlines the potential of this toolkit to advance our understanding of the ecological and evolutionary relevance of immune system variation in a natural setting. PMID:26646722

  8. Step-by-step synchronous variations of planetary natural processes in 1997-1998 and their uniform mechanism: phenomenon of "galloping of the core"

    Science.gov (United States)

    Barkin, Yu. V.

    2009-04-01

    "For an explanation of observably step-by-step variations of geodynamic and geophysical processes the mechanism of sharp sporadic relative displacements of the core and the mantle and deformations of the mantle in the certain periods of time (the phenomenon of "galloping of the core") is offered. Apparently, this mechanism results in spasmodic variations of axial rotation of the Earth, causes gallop in value of a phase of Chandler motion of a pole, to sharp changes of the intense condition in zones of catastrophes" ([1], p. 61). According to geodynamic model the step changes first of all should to be observed in motion of a geocenter as it reflects relative displacement of the centers of mass of the core and the mantle [1]. A gallop of natural processes in northern and southern hemispheres is characterized by the certain asymmetry. In result the step changes are tested by trend components of secular changes of parameters. In another words and activity (intensity) and trends of its secular changes test synchronous certain steps. Geocenter. According to observation data of DORIS spasmodic changes of polar rotation of a geocenter in a projection to an equatorial coordinate plane in 1997-1999 are revealed. On data DORIS in values of polar coordinate of a geocenter were observed gallop up to 20-30 cm. Changes of trend components have tested gallop which can be estimated in -2 mm in coordinate x, -5 mm in coordinate y and in -10 mm in coordinate z. Trajectory of a geocenter. A bend of a trajectory of long - periodic trend "trace" of a geocenter (its epicentre) on a surface of the Earth in 1997-1998 has been discovered (Zotov, Barkin, Lyubushin, 2008). It serves as direct confirmation of the assumption about a fundamental role of interaction and the forced relative displacements of the basic shells of the Earth, first of all the core and the mantle, both their stimulating and directing role in all planetary processes (Barkin, 2002). Gravitational field. On the data of

  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. Simple quantitative PCR approach to reveal naturally occurring and mutation-induced repetitive sequence variation on the Drosophila Y chromosome.

    Directory of Open Access Journals (Sweden)

    John C Aldrich

    Full Text Available Heterochromatin is a significant component of the human genome and the genomes of most model organisms. Although heterochromatin is thought to be largely non-coding, it is clear that it plays an important role in chromosome structure and gene regulation. Despite a growing awareness of its functional significance, the repetitive sequences underlying some heterochromatin remain relatively uncharacterized. We have developed a real-time quantitative PCR-based method for quantifying simple repetitive satellite sequences and have used this technique to characterize the heterochromatic Y chromosome of Drosophila melanogaster. In this report, we validate the approach, identify previously unknown satellite sequence copy number polymorphisms in Y chromosomes from different geographic sources, and show that a defect in heterochromatin formation can induce similar copy number polymorphisms in a laboratory strain. These findings provide a simple method to investigate the dynamic nature of repetitive sequences and characterize conditions which might give rise to long-lasting alterations in DNA sequence.

  11. 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. PMID:26872499

  12. 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.

  13. Natural C-14 variations and consequences for sea-level fluctuations and frequency analysis of periods of peat growth

    International Nuclear Information System (INIS)

    The rise in sea level during the past 18,000 years has been studied largely by means of radiocarbon dating. The question whether small fluctuations are superimposed on the steadily rising sea level is discussed. Support for this is the observed succession of clastic deposits and peat layers, resulting from alternating periods of transgressive and regressive activity. However, irregularities in the 14C time scale might not only give rise to apparent steps in the relative sea-level rise, but also to clustering of 14C dates of geological finds at certain 14C intervals. Therefore, until there is more evidence the succession of clastic deposits and peat layers is interpreted as caused by local disasters at certain times and random regressive peat growth during quiet periods. (Auth.)

  14. 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.

  15. 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

    2014-12-01

    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. PMID:25344411

  16. A population-based study relevant to seasonal variations in causes of death in children undergoing surgery for congenital cardiac malformations

    OpenAIRE

    Eskedal, Leif T.; Hagemo, Petter S.; Eskild, Anne; Frøslie, Kathrine F; Seiler, Stephen; Thaulow, Erik

    2007-01-01

    Aims: Our objectives were, first, to study seasonal distribution of perioperative deaths within 30 days after surgery, and late death, in children undergoing surgery for congenitally malformed hearts, and second, to study the causes of late death. Methods: We analysed a retrospective cohort of 1,753 children with congenital cardiac malformations born and undergoing surgery in the period from 1990 through 2002 with a special focus on the causes of late death. The data was obtained from the...

  17. Unit-specific calibration of Actigraph accelerometers in a mechanical setup - is it worth the effort? The effect on random output variation caused by technical inter-instrument variability in the laboratory and in the field

    DEFF Research Database (Denmark)

    Moeller, Niels C; Korsholm, Lars; Kristensen, Peter L;

    2008-01-01

    , the primary aim of this study was to calculate and apply unit-specific calibration factors in multiple accelerometers in order to examine the impact on random output variation caused by inter-instrument variability. METHODS: Instrument-specific calibration factors were estimated in 25 MTI- and 53 CSA...... during free living conditions. RESULTS: Calibration reduced inter-instrument variability considerably in the mechanical setup, both in the MTI instruments (raw SDbetween units = 195 counts*min-1 vs. calibrated SDbetween units = 65 counts*min-1) and in the CSA instruments (raw SDbetween units = 343 counts.......3% vs. CVcalibrated = 35.7%). High correlations (r = 0.99 & r = 0.98, respectively) were observed between raw and calibrated field data, and the proportion of the total variation caused by the MTI- and CSA monitor was estimated to be only 1.1% and 4.2%, respectively. Compared to the CSA instruments, a...

  18. 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...

  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. 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

    Science.gov (United States)

    Gavrichkova, O.; Proietti, S.; Moscatello, S.; Portarena, S.; Battistelli, A.; Matteucci, G.; Brugnoli, E.

    2011-10-01

    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 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 assimilation to the trunk

  1. Utilization of natural variations in the isotopic abundance of 15N to trace the source of aquifer pollution by nitrates

    International Nuclear Information System (INIS)

    The validity of using the natural isotope nitrogen-15 to trace the source of nitrates contained in aquifers is discussed with reference to experimental devices (lysimeters and experimental plots) and for examples chosen from the Paris area. There are a number of sources of nitrates: (1) industrially synthesized nitrates (fertilizers); (2) nitrates produced by oxidation of organic matter associated with human, agricultural or urban activities; (3) nitrates synthesized in the soil by the decay of organic matter. In the examples studied these sources differ in their 15N content: (1) fertilizers have a delta15N close to zero (atmospheric nitrogen); (2) the nitrates originating from organic pollution have high delta15N (above 10-12 per mille) and this 15N enrichment is associated with the volatilization of ammonia during the ammonia stage of mineralization; (3) the isotopic characterization of the nitrates produced by organic matter in the soil is less evident. Citing several examples, the author demonstrates that these three sources are diffentiated isotopically. Consideration of the parameters nitrate concentration/isotopic composition reveals simple mixture curves. In the most complicated cases - where there is association with other isotopic (3H) or chemical parameters - it is possible qualitatively to trace the sources of nitrogen pollution

  2. 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

    2015-07-01

    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

  3. 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. PMID:27096075

  4. 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

  5. Variations in natural abundances of 15N and 13C in potassium fed lentil plants grown under water stress

    International Nuclear Information System (INIS)

    The impact of two K-fertilizer treatments [K0 (0) and K1 (150 kg K2O/ha)] on dry matter production and N2 fixation (Ndfa) by Lentil (Lens culinaris.) was evaluated in a pot experiment. The plants were also subjected to three soil moisture regimes starting from bud flower initiation stage to pod formation (low, 45-50%. Moderate, 55-60% and high 75-80% of field capacity, abbreviated as FC1, FC2 and FC3, respectively). The 15N natural abundance technique (%δ 15N) was employed to evaluate N2 fixation using barley as a reference crop. Moreover, the carbon isotope discrimination (%Δ 13C) was determined to assess factors responsible for crop performance variability in the different treatments. Water restriction occurring during the post-flowering period considerably affects growth and N2-fixation. However, K-fertilizer enhanced plant performance by overcoming water shortage influences. The delta 15N values in lentils ranged from +0.67 to +1.36% depending on soil moisture and K-fertilizer treatments. Whereas, those of N2 fixation and the reference plant were -0.45 and +2.94%, respectively. Consequently, Ndfa% ranged from 45 and 65%. Water stress reduced Δ 13C values in the FC1K0 And FC1K1 treatments. However, K fertilizer enhanced the whole plants Δ 13C along with dry matter yield and N2 fixation. The water stressed plants amended with K (FC1K1) seemed to be the best treatment because of its highest pod yield, high N balance and N2-fixation with low consumption of irrigation water. This illustrates the ecological and economical importance of K-fertilizer in alleviating water stress occurring during the post-flowering period of lentil.(Authors)

  6. 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.

  7. Variations in natural abundances of 15N and 13C in potassium fed lentil plants grown under water stress

    International Nuclear Information System (INIS)

    The impact of two K-fertilizer treatments [K0 (0) and K1 (150 kg K2O/ha)] on dry matter production and N2 fixation (Ndfa) by Lentil (Lens culinaris.) was evaluated in a pot experiment. The plants were also subjected to three soil moisture regimes starting from bud flower initiation stage to pod formation (low, 45-50%; moderate, 55-60% and high 75-80% of field capacity, abbreviated as FC1, FC2 and FC3, respectively). The 15N natural abundance technique (%δ 15N) was employed to evaluate N2 fixation using barley as a reference crop. Moreover, the carbon isotope discrimination (%Δ 13C) was determined to assess factors responsible for crop performance variability in the different treatments. Water restriction occurring during the post-flowering period considerably affects growth and N2-fixation. However, K-fertilizer enhanced plant performance by overcoming water shortage influences. The δ 15N values in lentils ranged from +0.67 to +1.36% depending on soil moisture and K-fertilizer treatments; whereas, those of N2 fixation and the reference plant were -0.45 and +2.94%, respectively. Consequently, Ndfa% ranged from 45 and 65%. Water stress reduced Δ 13C values in the FC1K0 And FC1K1 treatments. However, K fertilizer enhanced the whole plants Δ 13C along with dry matter yield and N2fixation. The water stressed plants amended with K (FC1K1) seemed to be the best treatment because of its highest pod yield, high N balance and N2-fixation with low consumption of irrigation water. This illustrates the ecological and economical importance of K-fertilizer in alleviating water stress occurring during the post-flowering period of lentil.(Authors)

  8. 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...

  9. Variation in prescribing of lipid-lowering medication in primary care is associated with incidence of cardiovascular disease and all-cause mortality in people with screen-detected diabetes: findings from the ADDITION-Denmark trial

    Science.gov (United States)

    Simmons, R K; Carlsen, A H; Griffin, S J; Charles, M; Christiansen, J S; Borch-Johnsen, K; Sandbæk, A; Lauritzen, T

    2014-01-01

    Aims To examine variation between general practices in the prescription of lipid-lowering treatment to people with screen-detected Type 2 diabetes, and associations with practice and participant characteristics and risk of cardiovascular events and all-cause mortality. Methods Observational cohort analysis of data from 1533 people with screen-detected Type 2 diabetes aged 40–69 years from the ADDITION-Denmark study. One hundred and seventy-four general practices were cluster randomized to receive: (1) routine diabetes care according to national guidelines (623 individuals), or (2) intensive multifactorial target-driven management (910 individuals). Multivariable logistic regression was used to quantify the association between the proportion of individuals in each practice who redeemed prescriptions for lipid-lowering medication in the two years following diabetes diagnosis and a composite cardiovascular disease (CVD) outcome, adjusting for age, sex, prevalent chronic disease, baseline CVD risk factors, smoking and lipid-lowering medication, and follow-up time. Results The proportion of individuals treated with lipid-lowering medication varied widely between practices (0–100%). There were 118 CVD events over 9431 person-years of follow-up. For the whole trial cohort, the risk of CVD was significantly higher in practices in the lowest compared with the highest quartile for prescribing lipid-lowering medication [adjusted odds ratio (OR) 3.4, 95% confidence interval (CI) 1.6–7.3]. Similar trends were found for all-cause mortality. Conclusions More frequent prescription of lipid-lowering treatment was associated with a lower incidence of CVD and all-cause mortality. Improved understanding of factors underlying practice variation in prescribing may enable more frequent use of lipid-lowering treatment. The results highlight the benefits of intensive treatment of people with screen-detected diabetes (Clinical Trials Registry No; NCT 00237549). What's new Despite

  10. 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

  11. 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.

  12. Genotypic and Environmental Impact on Natural Variation of Nutrient Composition in 50 Non Genetically Modified Commercial Maize Hybrids in North America.

    Science.gov (United States)

    Cong, Bin; Maxwell, Carl; Luck, Stanley; Vespestad, Deanne; Richard, Keith; Mickelson, James; Zhong, Cathy

    2015-06-10

    This study was designed to assess natural variation in composition and metabolites in 50 genetically diverse non genetically modified maize hybrids grown at six locations in North America. Results showed that levels of compositional components in maize forage were affected by environment more than genotype. Crude protein, all amino acids except lysine, manganese, and β-carotene in maize grain were affected by environment more than genotype; however, most proximates and fibers, all fatty acids, lysine, most minerals, vitamins, and secondary metabolites in maize grain were affected by genotype more than environment. A strong interaction between genotype and environment was seen for some analytes. The results could be used as reference values for future nutrient composition studies of genetically modified crops and to expand conventional compositional data sets. These results may be further used as a genetic basis for improvement of the nutritional value of maize grain by molecular breeding and biotechnology approaches. PMID:25971869

  13. Genetic drift vs. natural selection in a long-term small isolated population: major histocompatibility complex class II variation in the Gulf of California endemic porpoise (Phocoena sinus).

    Science.gov (United States)

    Munguia-Vega, Adrian; Esquer-Garrigos, Yareli; Rojas-Bracho, Lorenzo; Vazquez-Juarez, Ricardo; Castro-Prieto, Aines; Flores-Ramirez, Sergio

    2007-10-01

    Although many studies confirm long-term small isolated populations (e.g. island endemics) commonly sustain low neutral genetic variation as a result of genetic drift, it is less clear how selection on adaptive or detrimental genes interplay with random forces. We investigated sequence variation at two major histocompatibility complex (Mhc) class II loci on a porpoise endemic to the upper Gulf of California, México (Phocoena sinus, or vaquita). Its unique declining population is estimated around 500 individuals. Single-strand conformation polymorphism analysis revealed one putative functional allele fixed at the locus DQB (n = 25). At the DRB locus, we found two presumed functional alleles (n = 29), differing by a single nonsynonymous nucleotide substitution that could increase the stability at the dimer interface of alphabeta-heterodimers on heterozygous individuals. Identical trans-specific DQB1 and DRB1 alleles were identified between P. sinus and its closest relative, the Burmeister's porpoise (Phocoena spinipinnis). Comparison with studies on four island endemic mammals suggests fixation of one allele, due to genetic drift, commonly occurs at the DQA or DQB loci (effectively neutral). Similarly, deleterious alleles of small effect are also effectively neutral and can become fixed; a high frequency of anatomical malformations on vaquita gave empirical support to this prediction. In contrast, retention of low but functional polymorphism at the DRB locus was consistent with higher selection intensity. These observations indicated natural selection could maintain (and likely also purge) some crucial alleles even in the face of strong and prolonged genetic drift and inbreeding, suggesting long-term small populations should display low inbreeding depression. Low levels of Mhc variation warn about a high susceptibility to novel pathogens and diseases in vaquita. PMID:17727623

  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. 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. PMID:23140062

  16. 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.

  17. Comparison of the incidence, nature and cause of injuries sustained on dirt field and artificial turf field by amateur football players

    Directory of Open Access Journals (Sweden)

    Kordi Ramin

    2011-02-01

    Full Text Available Abstract Background Data on the incidence, nature, severity and cause of match football injuries sustained on dirt field are scarce. The objectives of this study was to compare the incidence, nature, severity and cause of match injuries sustained on dirt field and artificial turf field by amateur male football players. Methods A prospective two-cohort design was employed. Participants were 252 male football players (mean age 27 years, range 18-43 in 14 teams who participated in a local championship carried on a dirt field and 216 male football players (mean age 28 years, range 17-40 in 12 teams who participated in a local championship carried on a artificial turf field in the same zone of the city. Injury definitions and recording procedures were compliant with the international consensus statement for epidemiological studies of injuries in football. Results The overall incidence of match injuries for men was 36.9 injuries/1000 player hours on dirt field and 19.5 on artificial turf (incidence rate ratio 1.88; 95% CI 1.19-3.05. Most common injured part on dirt field was ankle (26.7% and on artificial turf was knee (24.3%. The most common injury type in the dirt field was skin injuries (abrasion and laceration and in the artificial turf was sprain and ligament injury followed by haematoma/contusion/bruise. Most injuries were acute (artificial turf 89%, dirt field 91% and resulted from player-to-player contact (artificial turf 59.2%, dirt field 51.4%. Most injuries were slight and minimal in dirt field cohort but in artificial turf cohort the most injuries were mild. Conclusions There were differences in the incidence and type of football match injuries sustained on dirt field and artificial turf.

  18. Transition from natural convection or nucleate boiling regime to nucleate boiling or film boiling regime caused by a rapid pressure reduction in highly pressurized and subcooled water

    International Nuclear Information System (INIS)

    Transient boiling processes caused by exponentially decreasing system pressures with various decreasing pressure-reduction periods from the initial heat flux on a horizontal cylinder in a pool of highly subcooled water measured were divided into three groups for low and intermediate initial heat flux in natural convection regime and for high initial heat flux in nucleate boiling. The transitions from low initial heat flux values to stable nucleate boiling occurred independently of the pressure-reduction period values. The transitions from intermediate and high initial heat flux values to stable film boiling occurred for the short pressure-reduction period values, although those to stable nucleate boiling occurred for the long pressure-reduction period values. The mechanism of transient boiling process caused by an exponentially decreasing system pressure with a decreasing pressure-reduction period from an initial heat flux on a horizontal cylinder in a pool of highly subcooled water was clarified on the graph of α/q0.7 versus system pressure with the curves of corresponding fully developed nucleate boiling, incipient nucleate boiling due to unflooded cavities with vapor, and incipient heterogeneous spontaneous nucleation (HSN) due to flooded cavities without vapor. The transitions to stable nucleate boiling from the low initial heat flux values occurred independently of the pressure-reduction period values. The transitions from intermediate and high initial heat flux values in natural convection and nucleate boiling to stable film boiling occurred due to the HSN for short pressure-reduction period values; however those to stable nucleate boiling occurred for long pressure-reduction values. (author)

  19. Thlaspi caerulescens (Brassicaceae) population genetics in western Switzerland: is the genetic structure affected by natural variation of soil heavy metal concentrations?

    Science.gov (United States)

    Besnard, Guillaume; Basic, Nevena; Christin, Pascal-Antoine; Savova-Bianchi, Dessislava; Galland, Nicole

    2009-03-01

    Thlaspi caerulescens (Brassicaceae) is a promising plant model with which to study heavy metal hyperaccumulation. Population genetics studies are necessary for a better understanding of its history, which will be useful for further genomic studies on the evolution of heavy metal hyperaccumulation.The genetic structure of 24 natural Swiss locations was investigated using nuclear and plastid loci. Population genetics parameters were estimated and genetic pools were identified using Bayesian inference on eight putatively neutral nuclear loci.Finally, the effect of cadmium (Cd) and zinc (Zn) soil concentrations on genetic differentiation at loci located in genes putatively involved in heavy metal responses was examined using partial Mantel tests in Jura, western Switzerland.Four main genetic clusters were recognized based on nuclear and plastid loci,which gave mostly congruent signals. In Jura, genetic differentiation linked to heavy metal concentrations in soil was shown at some candidate loci, particularly for genes encoding metal transporters. This suggests that natural selection limits gene flow between metalliferous and non metalliferous locations at such loci.Strong historical factors explain the present genetic structure of Swiss T. caerulescens populations, which has to be considered in studies testing for relationships between environmental and genetic variations. Linking of genetic differentiation at candidate genes with soil characteristics offers new perspectives in the study of heavy metal hyperaccumulation. PMID:19076982

  20. The nature and causes of the global water crisis: Syndromes from a meta-analysis of coupled human-water studies

    Science.gov (United States)

    Srinivasan, V.; Lambin, E. F.; Gorelick, S. M.; Thompson, B. H.; Rozelle, S.

    2012-10-01

    Freshwater scarcity has been cited as the major crisis of the 21st century, but it is surprisingly hard to describe the nature of the global water crisis. We conducted a meta-analysis of 22 coupled human-water system case studies, using qualitative comparison analysis (QCA) to identify water resource system outcomes and the factors that drive them. The cases exhibited different outcomes for human wellbeing that could be grouped into a six "syndromes": groundwater depletion, ecological destruction, drought-driven conflicts, unmet subsistence needs, resource capture by elite, and water reallocation to nature. For syndromes that were not successful adaptations, three characteristics gave cause for concern: (1) unsustainability—a decline in the water stock or ecosystem function that could result in a long-term steep decline in future human wellbeing; (2) vulnerability—high variability in water resource availability combined with inadequate coping capacity, leading to temporary drops in human wellbeing; (3) chronic scarcity—persistent inadequate access and hence low conditions of human wellbeing. All syndromes could be explained by a limited set of causal factors that fell into four categories: demand changes, supply changes, governance systems, and infrastructure/technology. By considering basins as members of syndrome classes and tracing common causal pathways of water crises, water resource analysts and planners might develop improved water policies aimed at reducing vulnerability, inequity, and unsustainability of freshwater systems.

  1. Expression conservation within the circadian clock of a monocot: natural variation at barley Ppd-H1 affects circadian expression of flowering time genes, but not clock orthologs

    Directory of Open Access Journals (Sweden)

    Campoli Chiara

    2012-06-01

    Full Text Available Abstract Background The circadian clock is an endogenous mechanism that coordinates biological processes with daily changes in the environment. In plants, circadian rhythms contribute to both agricultural productivity and evolutionary fitness. In barley, the photoperiod response regulator and flowering-time gene Ppd-H1 is orthologous to the Arabidopsis core-clock gene PRR7. However, relatively little is known about the role of Ppd-H1 and other components of the circadian clock in temperate crop species. In this study, we identified barley clock orthologs and tested the effects of natural genetic variation at Ppd-H1 on diurnal and circadian expression of clock and output genes from the photoperiod-response pathway. Results Barley clock orthologs HvCCA1, HvGI, HvPRR1, HvPRR37 (Ppd-H1, HvPRR73, HvPRR59 and HvPRR95 showed a high level of sequence similarity and conservation of diurnal and circadian expression patterns, when compared to Arabidopsis. The natural mutation at Ppd-H1 did not affect diurnal or circadian cycling of barley clock genes. However, the Ppd-H1 mutant was found to be arrhythmic under free-running conditions for the photoperiod-response genes HvCO1, HvCO2, and the MADS-box transcription factor and vernalization responsive gene Vrn-H1. Conclusion We suggest that the described eudicot clock is largely conserved in the monocot barley. However, genetic differentiation within gene families and differences in the function of Ppd-H1 suggest evolutionary modification in the angiosperm clock. Our data indicates that natural variation at Ppd-H1 does not affect the expression level of clock genes, but controls photoperiodic output genes. Circadian control of Vrn-H1 in barley suggests that this vernalization responsive gene is also controlled by the photoperiod-response pathway. Structural and functional characterization of the barley circadian clock will set the basis for future studies of the adaptive significance of the circadian clock in

  2. The prevalence of anatomical variations that can cause inadvertent dural puncture when performing caudal block in Koreans: a study using magnetic resonance imaging.

    Science.gov (United States)

    Joo, J; Kim, J; Lee, J

    2010-01-01

    The purpose of this study was to investigate the prevalence of the anatomical abnormalities that can induce inadvertent dural puncture when performing caudal block. The anatomy of the lumbo-sacral area was evaluated using magnetic resonance imaging. In 2462 of the 2669 patients imaged, the dural sac terminal was located between the upper half of the 1st sacral vertebra and the lower half of the 2nd sacral vertebra. In 22 cases (0.8%), the dural sac terminal and the spinal canal were located at or below the 3rd sacral vertebra, and these were cases of simple anatomical variations. As regards pathologic conditions, there was one case of sacral meningocoele and 46 cases of sacral perineural cyst. In 21 cases (0.8%) out of the 46 perineural cyst cases, the cyst could be found at or below the 3rd sacral vertebra level. Inadvertent dural puncture may happen when performing caudal block in patients with such abnormal anatomy. PMID:19922508

  3. Changes in pulse pressure variation and plethysmographic variability index caused by hypotension-inducing hemorrhage followed by volume replacement in isoflurane-anesthetized dogs.

    Science.gov (United States)

    Klein, Adriana V; Teixeira-Neto, Francisco J; Garofalo, Natache A; Lagos-Carvajal, Angie P; Diniz, Miriely S; Becerra-Velásquez, Diana R

    2016-03-01

    OBJECTIVE To compare changes in pulse pressure variation (PPV) and plethysmographic variability index (PVI) induced by hemorrhage followed by volume replacement (VR) in isoflurane-anesthetized dogs. ANIMALS 7 healthy adult dogs. PROCEDURE Each dog was anesthetized with isoflurane and mechanically ventilated. End-tidal isoflurane concentration was adjusted to maintain mean arterial pressure (MAP) at 60 to 70 mm Hg before hemorrhage. Controlled hemorrhage was initiated and continued until the MAP decreased to 40 to 50 mm Hg, then autologous blood removed during hemorrhage was retransfused during VR. Various physiologic variables including PPV and PVI were recorded immediately before (baseline) and after controlled hemorrhage and immediately after VR. RESULTS Mean ± SD PPV and PVI were significantly increased from baseline after hemorrhage (PPV, 20 ± 6%; PVI, 18 ± 4%). After VR, the mean PPV (7 ± 3%) returned to a value similar to baseline, whereas the mean PVI (10 ± 3%) was significantly lower than that at baseline. Cardiac index (CI) and stroke index (SI) were significantly decreased from baseline after hemorrhage (CI, 2.07 ± 0.26 L/min/m(2); SI, 20 ± 3 mL/beat/m(2)) and returned to values similar to baseline after VR (CI, 4.25 ± 0.63 L/min/m(2); SI, 36 ± 6 mL/beat/m(2)). There was a significant positive correlation (r(2) = 0.77) between PPV and PVI after hemorrhage. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that both PPV and PVI may be useful for identification of dogs that respond to VR with increases in SI and CI (ie, dogs in the preload-dependent limb of the Frank-Starling curve). PMID:26919599

  4. Temporal Variation in Natural Gas Seep Rate and Influence Factors in the Lingtou Promontory Seep Field of the Northern South China Sea

    Directory of Open Access Journals (Sweden)

    Pengfei Di

    2014-01-01

    Full Text Available Natural hydrocarbon seeps in marine environment are important sources of methane and other greenhouse gases into the ocean and the atmosphere. This greenhouse gas seepage influences the global methane budget and global climate change. Hydrocarbon seeps on the shallow seabed produce a near-shore gas bubble zone along the western coast of Hainan Island, in the northern South China Sea. However, few studies on the quantitative value of the methane flux and on temporal variation and influence factors of hydrocarbon seeps have been conducted until now. This study describes the results of continuous gas vent measurements for 420 hours on the seabed of the Lingtou promontory shore. The amount of gas released from a single gas vent was 30.5 m3 during the measurement period. The gas flow rate ranged from 22 - 72 L h-1, with an average rate of 53.4 L h-1. The time series analyses of the 420-hour record clearly show three principal tidal components with periods of 5.4, 4.6, and 2.4 hours, which are the main factors controlling the gas flow rate. Low flow rates were associated with high tide and high flow rates associated with low tide. A 1-m increase in seawater height results in a decrease of 20 - 30 L h-1 or 35 - 56% of the hourly flow rate. Therefore, the changes in gas volume escape from the pore could be attributed to the hydrostatic pressure effect induced by water depth. This dominant mechanism controlled pore activation as well as the gas flow rate, suggesting that in the marine environment, especially the shallow-water shelf area, sea level changes may result in great variations in methane release into the ocean and atmosphere.

  5. Variation of natural sup 15 N abundance of crops and soils in Japan with special reference to the effect of soil conditions and fertilizer application

    Energy Technology Data Exchange (ETDEWEB)

    Yoneyama, Tadakatsu (National Agriculture Research Center, Tsukuba, Ibaraki (Japan). Dept. of Soils and Fertilizers); Kouno, Kazumi; Yazaki, Jinya

    1990-12-01

    The natural {sup 15}N abundance ({delta}{sup 15}N) of the crops subjected to long-term fertilizer treatments under paddy and upland conditions in the different experimental stations throughout Japan were analyzed. The {delta}{sup 15}N values of the grains of paddy rice which were +6.3 per mille on the average in the fields without application of chemical fertilizers decreased by the treatment with chemical fertilizers. The average {delta}{sup 15}N values of the upland crops were lower than those of paddy rice without application of N fertilizers. The {delta}{sup 15}N values of upland crops decreased with the dose of chemical fertilizer N, but increased with the application of composts containing animal feces. The pot experiments using three soils showed that the {delta}{sup 15}N values of paddy rice were higher than those of upland rice and sorghum and that these values were comparable to the {delta}{sup 15}N values of ammonium and nitrate produced in the incubated soils, respectively. The {delta}{sup 15}N values of fertilizer N absorbed by paddy rice were higher than those of fertilizer N, whereas the {delta}{sup 15}N values of the fertilizer N in upland rice and sorghum were increased in the alluvial soils but decreased in Andosols as compared to those of fertilizer N applied. The {delta}{sup 15}N values of the Andosols in Japan showed small variations, with an average value of +6.5 per mille, whereas those of alluvial soils in Japan showed large variations with an average value lower than that of Andosols. (author).

  6. Variation of natural 15N abundance of crops and soils in Japan with special reference to the effect of soil conditions and fertilizer application

    International Nuclear Information System (INIS)

    The natural 15N abundance (δ15N) of the crops subjected to long-term fertilizer treatments under paddy and upland conditions in the different experimental stations throughout Japan were analyzed. The δ15N values of the grains of paddy rice which were +6.3 per mille on the average in the fields without application of chemical fertilizers decreased by the treatment with chemical fertilizers. The average δ15N values of the upland crops were lower than those of paddy rice without application of N fertilizers. The δ15N values of upland crops decreased with the dose of chemical fertilizer N, but increased with the application of composts containing animal feces. The pot experiments using three soils showed that the δ15N values of paddy rice were higher than those of upland rice and sorghum and that these values were comparable to the δ15N values of ammonium and nitrate produced in the incubated soils, respectively. The δ15N values of fertilizer N absorbed by paddy rice were higher than those of fertilizer N, whereas the δ15N values of the fertilizer N in upland rice and sorghum were increased in the alluvial soils but decreased in Andosols as compared to those of fertilizer N applied. The δ15N values of the Andosols in Japan showed small variations, with an average value of +6.5 per mille, whereas those of alluvial soils in Japan showed large variations with an average value lower than that of Andosols. (author)

  7. 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

  8. The Local-time variations of Lunar Prospector epithermal-neutron data

    OpenAIRE

    Teodoro, L F A; Lawrence, D.J.; Eke, V. R.; Elphic, R. E.; Feldman, W. C.; Maurice, S.; Siegler, M. A.; Paige, D. A.

    2015-01-01

    We assess local-time variations of epithermal-neutron count rates measured by the Lunar Prospector Neutron Spectrometer. We investigate the nature of these variations and find no evidence to support the idea that such variations are caused by diurnal variations of hydrogen concentration across the lunar surface. Rather we find an anticorrelation between instrumental temperature and epithermal-neutron count rate. We have also found that the measured counts are dependent on the temperatures of ...

  9. 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.

  10. Inventory of emergencies and disasters in the Aburra Valley. Caused by natural and human phenomena in the period 1880-2007

    International Nuclear Information System (INIS)

    In recent years, natural and man induced disasters have been increasingly affecting numbers of people throughout the world, especially in the developing countries located within the tropics, such as Colombia. For this reason complete and high quality database on disasters and their human and economic impact is very much needed. It becomes an important tool for planners, policy makers, and field agencies engaged in preparedness and risk assessment. The Aburra Valley Metropolitan Area has implemented a local disaster database using the software DesInventar, developed in 1992 by La Red, Social Studies Network for Disaster Prevention in Latin America. The DesInventar methodology consists of two modules: DesInventar module, allows entry of space and temporal data, types of events, causes and sources through predefined fields? and DesConsultar module, allows easy database access, elaboration of queries including relations between the variables of effects, types of events, causes, sites, dates, etc, as well the use of tables, graphics and thematic maps. This local disaster database has been built using the data provided by previous works from EAFIT University, SIMPAD, Hormaza (1991) and Saldarriaga (2002). Here, we use the DesInventar methodology to identify the human and economic impact of natural and man induced disaster in the Aburra Valley. The current database indicates that the Aburra Valley has been affected by a large amount of events ranging in magnitude between small to moderate. During the period 1880 - 2007 a total of 6750 events were registered, classified as flooding events (42%), landslides (35%), and forest fires (15%). Manmade disasters are small, however its impact and recurrence has increased during the last two decades. In a global perspective of the Aburra Valley,we concluded that the most populated cities in the valley are the most affected, e.g. Medellin: 72% of events and 2'223.660 inhabitants? Itagui: 5,4% and 231.768 inhabitants? Envigado: 4

  11. 英吉沙县1965-2009年蒸发量变化特征及原因分析%The Variation Characteristics of Evaporation in Yingjisha County from 1965 to 2009 and the Cause Analysis

    Institute of Scientific and Technical Information of China (English)

    阿布都克日木·阿巴司

    2011-01-01

    Based on the evaporation data of Yingjisha weather station from 1965 to 2009, we analyzed the variation trend of evaporation and the factors caused the evaporation variation with the methods of climate trend coefficient and climate tendency ratio. The results showed that the annual, seasonal and monthly evaporation variation had presented obvious downtrend in recent 45 years. The main impact factors were the sunshine, wind speed, relative humidity and precipitation.%利用英吉沙国家气象观测站二级站1965-2009年小型蒸发皿蒸发量资料,采用气候倾向率和气候趋势系数方法分析了英吉沙蒸发量的变化趋势及引起蒸发量变化的气象因子,结果表明,英吉沙年和各季蒸发量均存在明显的减小趋势。影响蒸发量变化的因子主要有日照、风速、相对湿度和降水量。

  12. Effects of variation of oil and zinc oxide type on the gas barrier and mechanical properties of chlorobutyl rubber/epoxidised natural rubber blends

    International Nuclear Information System (INIS)

    Highlights: ► A (90:10) blend of CIIR and ENR by weight was used as the base. ► Different process oil and ZnO were used to optimize the gas barrier property. ► The minimum oxygen permeability is obtained using sheet ZnO. - Abstract: In many polymer applications such as inner tire liners and fuel hoses, imparting excellent gas barrier property is of prime importance. Researches in this direction had been done based on a judicious choice of polymer type or a blend thereof and the compounding ingredients. Though butyl rubber has been the polymer of choice because of its excellent gas barrier property, yet researches were targeted to improve the same with further modification in the polymer type and variation in compounding ingredients. In this study, a (90:10) blend of chlorobutyl rubber (CIIR) and Epoxdised Natural Rubber (ENR) by weight was used as the base. Four different types of process oil and three different types of zinc oxide (ZnO) at fixed predetermined concentrations were used to optimize the gas barrier and mechanical properties. In this blend, recycled aromatic oil (RAE) and sheet zinc oxide were effective in imparting the best overall combination of properties. Scanning Electron Microscopic (SEM) studies of ZnO were done to understand the structure property relationship

  13. 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.

  14. Exploring natural variation of Pinus pinaster Aiton using metabolomics: Is it possible to identify the region of origin of a pine from its metabolites?

    Science.gov (United States)

    Meijón, Mónica; Feito, Isabel; Oravec, Michal; Delatorre, Carolina; Weckwerth, Wolfram; Majada, Juan; Valledor, Luis

    2016-02-01

    Natural variation of the metabolome of Pinus pinaster was studied to improve understanding of its role in the adaptation process and phenotypic diversity. The metabolomes of needles and the apical and basal section of buds were analysed in ten provenances of P. pinaster, selected from France, Spain and Morocco, grown in a common garden for 5 years. The employment of complementary mass spectrometry techniques (GC-MS and LC-Orbitrap-MS) together with bioinformatics tools allowed the reliable quantification of 2403 molecular masses. The analysis of the metabolome showed that differences were maintained across provenances and that the metabolites characteristic of each organ are mainly related to amino acid metabolism, while provenances were distinguishable essentially through secondary metabolism when organs were analysed independently. Integrative analyses of metabolome, environmental and growth data provided a comprehensive picture of adaptation plasticity in conifers. These analyses defined two major groups of plants, distinguished by secondary metabolism: that is, either Atlantic or Mediterranean provenance. Needles were the most sensitive organ, where strong correlations were found between flavonoids and the water regime of the geographic origin of the provenance. The data obtained point to genome specialization aimed at maximizing the drought stress resistance of trees depending on their origin. PMID:26756581

  15. Influence of PhoP and intra-species variations on virulence of Yersinia pseudotuberculosis during the natural oral infection route.

    Directory of Open Access Journals (Sweden)

    Fabio Pisano

    Full Text Available The two-component regulatory system PhoP/PhoQ has been shown to (i control expression of virulence-associated traits, (ii confer survival and growth within macrophages and (iii play a role in Yersinia infections. However, the influence of PhoP on virulence varied greatly between different murine models of infection and its role in natural oral infections with frequently used representative isolates of Y. pseudotuberculosis was unknown. To address this issue, we constructed an isogenic set of phoP+ and phoP- variants of strain IP32953 and YPIII and analyzed the impact of PhoP using in vitro functionality experiments and a murine oral infection model, whereby we tested for bacterial dissemination and influence on the host immune response. Our results revealed that PhoP has a low impact on virulence, lymphatic and systemic organ colonization, and on immune response modulation by IP32953 and YPIII, indicating that PhoP is not absolutely essential for oral infections but may be involved in fine-tuning the outcome. Our work further revealed certain strain-specific differences in virulence properties, which do not strongly rely on the function of PhoP, but affect tissue colonization, dissemination and/or persistence of the bacteria. Highlighted intra-species variations may provide a potential means to rapidly adjust to environmental changes inside and outside of the host.

  16. 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.

  17. Unit-specific calibration of Actigraph accelerometers in a mechanical setup – Is it worth the effort? The effect on random output variation caused by technical inter-instrument variability in the laboratory and in the field

    Science.gov (United States)

    Moeller, Niels C; Korsholm, Lars; Kristensen, Peter L; Andersen, Lars B; Wedderkopp, Niels; Froberg, Karsten

    2008-01-01

    Background Potentially, unit-specific in-vitro calibration of accelerometers could increase field data quality and study power. However, reduced inter-unit variability would only be important if random instrument variability contributes considerably to the total variation in field data. Therefore, the primary aim of this study was to calculate and apply unit-specific calibration factors in multiple accelerometers in order to examine the impact on random output variation caused by inter-instrument variability. Methods Instrument-specific calibration factors were estimated in 25 MTI- and 53 CSA accelerometers in a mechanical setup using four different settings varying in frequencies and/or amplitudes. Calibration effect was analysed by comparing raw and calibrated data after applying unit-specific calibration factors to data obtained during quality checks in a mechanical setup and to data collected during free living conditions. Results Calibration reduced inter-instrument variability considerably in the mechanical setup, both in the MTI instruments (raw SDbetween units = 195 counts*min-1 vs. calibrated SDbetween units = 65 counts*min-1) and in the CSA instruments (raw SDbetween units = 343 counts*min-1 vs. calibrated SDbetween units = 67 counts*min-1). However, the effect of applying the derived calibration to children's and adolescents' free living physical activity data did not alter the coefficient of variation (CV) (children: CVraw = 30.2% vs. CVcalibrated = 30.4%, adolescents: CVraw = 36.3% vs. CVcalibrated = 35.7%). High correlations (r = 0.99 & r = 0.98, respectively) were observed between raw and calibrated field data, and the proportion of the total variation caused by the MTI- and CSA monitor was estimated to be only 1.1% and 4.2%, respectively. Compared to the CSA instruments, a significantly increased (9.95%) mean acceleration response was observed post hoc in the batch of MTI instruments, in which a significantly reduced inter-instrumental reliability

  18. Unit-specific calibration of Actigraph accelerometers in a mechanical setup – Is it worth the effort? The effect on random output variation caused by technical inter-instrument variability in the laboratory and in the field

    Directory of Open Access Journals (Sweden)

    Andersen Lars B

    2008-04-01

    Full Text Available Abstract Background Potentially, unit-specific in-vitro calibration of accelerometers could increase field data quality and study power. However, reduced inter-unit variability would only be important if random instrument variability contributes considerably to the total variation in field data. Therefore, the primary aim of this study was to calculate and apply unit-specific calibration factors in multiple accelerometers in order to examine the impact on random output variation caused by inter-instrument variability. Methods Instrument-specific calibration factors were estimated in 25 MTI- and 53 CSA accelerometers in a mechanical setup using four different settings varying in frequencies and/or amplitudes. Calibration effect was analysed by comparing raw and calibrated data after applying unit-specific calibration factors to data obtained during quality checks in a mechanical setup and to data collected during free living conditions. Results Calibration reduced inter-instrument variability considerably in the mechanical setup, both in the MTI instruments (raw SDbetween units = 195 counts*min-1 vs. calibrated SDbetween units = 65 counts*min-1 and in the CSA instruments (raw SDbetween units = 343 counts*min-1 vs. calibrated SDbetween units = 67 counts*min-1. However, the effect of applying the derived calibration to children's and adolescents' free living physical activity data did not alter the coefficient of variation (CV (children: CVraw = 30.2% vs. CVcalibrated = 30.4%, adolescents: CVraw = 36.3% vs. CVcalibrated = 35.7%. High correlations (r = 0.99 & r = 0.98, respectively were observed between raw and calibrated field data, and the proportion of the total variation caused by the MTI- and CSA monitor was estimated to be only 1.1% and 4.2%, respectively. Compared to the CSA instruments, a significantly increased (9.95% mean acceleration response was observed post hoc in the batch of MTI instruments, in which a significantly reduced inter

  19. Isotopic and trace element variations in the Ruby Batholith, Alaska, and the nature of the deep crust beneath the Ruby and Angayucham Terranes

    Science.gov (United States)

    Arth, Joseph G.; Zmuda, Clara C.; Foley, Nora K.; Criss, Robert E.; Patton, W.W., Jr.; Miller, T.P.

    1989-01-01

    Thirty-six samples from plutons of the Ruby batholith of central Alaska were collected and analyzed for 22 trace elements, and many were analyzed for the isotopic compositions of Sr, Nd, O, and Pb in order to delimit the processes that produced the diversity of granodioritic to granitic compositions, to deduce the nature of the source of magmas at about 110 Ma, and to characterize the deep crust beneath the Ruby and Angayucham terranes. Plutons of the batholith show a substantial range in initial 87Sr/86Sr (SIR) of 0.7055–0.7235 and a general decrease from southwest to northeast. Initial 143Nd/144Nd (NIR) have a range of 0.51150–0.51232 and generally increase from southwest to northeast. The δ18O values for most whole rocks have a range of +8.4 to +11.8 and an average of +10.3‰. Rb, Cs, U, and Th show large ranges of concentration, generally increase as SiO2 increases, and are higher in southwest than in northeast plutons. Sr, Ba, Zr, Hf, Ta, Sc, Cr, Co, and Zr show large ranges of concentration and generally decrease as SiO2 increases. Rare earth elements (REE) show fractionated patterns and negative Eu anomalies. REE concentrations and anomalies are larger in the southwest than in the northeast plutons. Uniformity of SIR and NIR in Sithylemenkat and Jim River plutons suggests a strong role for fractional crystallization or melting of uniform magma sources at depth. Isotopic variability in Melozitna, Ray Mountains, Hot Springs, and Kanuti plutons suggests complex magmatic processes such as magma mixing and assimilation, probably combined with fractional crystallization, or melting of a complex source at depth. The large variations in SIR and NIR in the batholith require a variation in source materials at depth. The southwestern plutons probably had dominantly siliceous sources composed of metamorphosed Proterozoic and Paleozoic upper crustal rocks. The northeastern plutons probably had Paleozoic sources that were mixtures of siliceous and intermediate

  20. Numerical Simulation on Landslide Stability Affected by Seepage Field Variation Caused by Tunnel Excavation%隧洞开挖渗流场变化对滑坡稳定性的影响数值模拟分析

    Institute of Scientific and Technical Information of China (English)

    张凡; 韩爱果; 任光明; 杜飞; 吴龙科; 詹可

    2015-01-01

    The aim of this research is to investigate in landslide’s seepage field,slope deformation and stability af-fected by tunnel excavation.On the basis of analysing the physical and mechanical and water physical properties of a landslide slope,we simulated the variation of groundwater level and seepage field before and after tunnel excava-tion using 3D finite difference software Modflow.Furthermore,by employing Geo-Studio,we analyzed the stability and deformation of landslide after water level changed in natural and excavation conditions.Results reveal that the groundwater seepage field changed after tunnel excavation,and obvious water inflow was found at the excavation ar-ea.As a result,the groundwater level decreased about 20m and apparent “sinkholes”appeared in the excavation area.The change of groundwater level was mainly reflected in the front edge of landslide.The deformation of 2 #secondary sliding body,which caused the deformation of 1 #secondary sliding body,exacerbated under the com-bined actions of weakened sliding resistance and increased effective stress.The maximum slope deformation of sec-ondary landslide above the tunnel reached 1 2.42 cm,but the stability changed slightly.%为研究隧洞开挖对滑坡渗流场、坡体变形及稳定性的影响,在对某滑坡滑体物理力学及水理性质进行研究的基础上,采用 Modflow 有限元差分三维软件对隧洞开挖前后的地下水位进行数值模拟计算,分析隧洞开挖后渗流场的变化,并以此结合 Geo-Studio 软件对滑坡处于天然及开挖情况下水位变化后的稳定性及变形进行了分析研究。结果表明:隧洞开挖后地下水渗流场发生改变,隧洞开挖处产生明显涌水现象,开挖2 a 后地下水位降低约20 m,开挖区形成明显“落水洞”,地下水位变化主要体现在滑坡前缘;隧洞上部2#次级滑体在抗滑力减弱和有效应力增大的双重作用下变形加剧,其下滑带动1#

  1. 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

  2. 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 the coseismic effects of these two earthquakes. The theoretical calculation of the stress drop agrees with our measurement.%为了监测汶川地震后断裂带附近的波速变化,2008年6月,我们利用快速响应探测系统,在龙门山断裂带北端进行了为期3周的连续观测实验.实验使用电动落锤作为主动震源,GPS连续同步授时的高精度数采作为接收系统.利用记录到的高时间精度观测数据,结合互相关时延检测技术,计算了P波和面波走时的相对变化,来表征地下波速的变化.我们观测到两次面波波速的异常变化,变化幅度最高达到2%,远远大于气压变化所能引起的波速变化.结合该时段内地震活动记录,我们认为面波的波速变化是由在附近发生的两次地震事件的同震效应引起的,该观测结果同理论计算结果相符.

  3. 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. PMID:23275581

  4. Sequence polymorphism of GroEL gene in natural population of Bacillus and Brevibacillus spp. that showed variation in thermal tolerance capacity and mRNA expression.

    Science.gov (United States)

    Sen, R; Tripathy, S; Padhi, S K; Mohanty, S; Maiti, N K

    2014-10-01

    GroEL, a class I chaperonin, plays an important role in the thermal adaptation of the cell and helps to maintain the viability of the cell under heat shock condition. Function of groEL in vivo depends on the maintenance of proper structure of the protein which in turn depends on the nucleotide and amino acid sequence of the gene. In this study, we investigated the changes in nucleotide and amino acid sequences of the partial groEL gene that may affect the thermotolerance capacity as well as mRNA expression of bacterial isolates. Sequences among the same species having differences in the amino acid level were identified as different alleles. The effect of allelic variation on the groEL gene expression was analyzed by comparison and relative quantification in each allele under thermal shock condition by RT-PCR. Evaluation of K a/K s ratio among the strains of same species showed that the groEL gene of all the species had undergone similar functional constrain during evolution. The strains showing similar thermotolerance capacity was found to carry same allele of groEL gene. The isolates carrying allele having amino acid substitution inside the highly ATP/ADP or Mg(2+)-binding region could not tolerate thermal stress and showed lower expression of the groEL gene. Our results indicate that during evolution of these bacterial species the groEL gene has undergone the process of natural selection, and the isolates have evolved with the groEL allelic sequences that help them to withstand the thermal stress during their interaction with the environment. PMID:24894903

  5. 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. PMID:22474217

  6. Investigation And Determination On Natural Radioactivity In Commonly Building Materials Used In Vietnam And Initial Assessment On Radiation Exposure Caused By Them

    International Nuclear Information System (INIS)

    , gravel aggregate, imported granite, marble, local granite, glazed tile, red-clay brick and cement, respectively. The average values of radon exhalation fraction (10-3 h) were 0.4359, 0.6843, 0.4895, 0.9011, 0.4503, 0.0323, 0.1136, and 0.1413 for the above kinds of building materials. The activity concentration index and the annual effective dose for a model room (dimensions of 4 m x 5 m x 2.8 m; thickness of 20 cm, and density of 2.35 g/cm3), in which the structures in a building causing the irradiation to be concerned were evaluated to assess the potential radiological hazard associated with these building materials. The results showed that the enhanced concentration values were sometimes felling into granite tiles, especially imported granite tiles; the potential of exceed the recommendation value was possible. These obtained data aimed to enlarge the database on natural radioactivity in commonly building materials used in Vietnam and to support technical aspects in hazard exposure reduction. (author)

  7. Different Degrees of Isolation of Groundwater as Cause of its Variability: Evidences from Isotopic and Hydrochemical Data and Water Level Seasonal Variation in Pantanal of Nhecolândia

    Directory of Open Access Journals (Sweden)

    Teodoro Isnard Ribeiro de Almeida

    2010-10-01

    Full Text Available This study aims to analyze the degree of isolation of natural lakes with unusual values of salinity and pH in the area ofPantanal da Nhecolândia, the largest field of lakes in the tropical zone of the planet. This process is still poorly understoodand is essential for understanding the entire environment. The salinity was measured by electrical conductivity and showsgreat variations. The possibility of important variability of evaporation or precipitation was dismissed because the lakes arein the same area and the region is flat. Therefore, salinity differences may be associated with a present processes, providedby different degrees of isolation between the lakes and the groundwater, or originated from salt deposits formed in the past,under arid climate. To test the first hypothesis, we analyzed the ratios of stable isotopes of oxygen and deuterium, since theisotopic fractionation that occurs during evaporation enriches the liquid phase in 18O and D. The correlation between theratios and electrical conductivity is exponential, indicating that the salinity increases with the isolation of the lakes from the groundwater and that a significant isolation of the lakes results in salinities ranging from intermediate to high. The study presents dataon seasonal variation in water level (July 2008, end of rainy season and October 2008, end of dry season of 14 lakes. The data showerratic decrease in the water level of fresh water lakes, which was interpreted as evidence of greater exchange of water between theselakes and the groundwater.

  8. Genetic diversity and population structure of a Sichuan sika deer (Cervus sichuanicus) population in Tiebu Nature Reserve based on microsatellite variation.

    Science.gov (United States)

    He, Ya; Wang, Zheng-Huan; Wang, Xiao-Ming

    2014-11-18

    Cervus sichuanicus is a species of sika deer (Cervus nippon Group). To date, research has mainly focused on quantity surveying and behavior studies, with genetic information on this species currently deficient. To provide scientific evidence to assist in the protection of this species, we collected Sichuan sika deer fecal samples from the Sichuan Tiebu Nature Reserve (TNR) and extracted DNA from those samples. Microsatellite loci of bovine were used for PCR amplification. After GeneScan, the genotype data were used to analyze the genetic diversity and population structure of the Sichuan sika deer in TNR. Results showed that the average expected heterozygosity of the Sichuan sika deer population in TNR was 0.562, equivalent to the average expected heterozygosity of endangered animals, such as Procapra przewalskii. Furthermore, 8 of 9 microsatellite loci significantly deviated from the Hardy-Weinberg equilibrium and two groups existed within the Sichuan sika deer TNR population. This genetic structure may be caused by a group of Manchurian sika deer (Cervus hortulorum) released in TNR. PMID:25465089

  9. High mortality by natural and unnatural causes: a 10 year follow up study of patients admitted to a poisoning treatment centre after suicide attempts.

    OpenAIRE

    Nordentoft, M; Breum, L; Munck, L K; Nordestgaard, A G; Hunding, A; Laursen Bjaeldager, P A

    1993-01-01

    OBJECTIVE--To describe mortality by suicide and other causes of death in a group of patients who attempted suicide, and to identify predictive factors. DESIGN--10 year follow up study based on records of suicide attempters in 1980. SETTING--Poisoning treatment centre at a general hospital. SUBJECTS--974 patients aged 15 and over referred to the poisoning treatment centre after deliberate self poisoning. MAIN OUTCOME MEASURES--Death by different causes registered in the Danish death cause regi...

  10. Sensitivity of subalpine tree seedlings and alpine plants to natural and manipulated climate variation: Initial results from an Alpine Treeline Warming Experiment (Invited)

    Science.gov (United States)

    Kueppers, L. M.

    2010-12-01

    Niche models and paleoecological studies indicate that future climate change will alter the geographic distributions of plant species. Changes in temperature, snowmelt timing, or moisture conditions at one edge of a species’ range may have different consequences for recruitment, carbon exchange, phenology, and survival than changes at another edge. Similarly, local genetic adaptation may constrain species and community responses to climate change. We have established a new experiment to investigate potential shifts in the distribution of subalpine tree species, and the alpine species they might replace. We are asking how tree species recruitment and alpine species growth and reproduction vary within their current ranges, and in response to temperature and soil moisture manipulations. We are also examining whether genetic provenance and ecosystem processes constrain tree seedling and alpine herb responses. Our Alpine Treeline Warming Experiment is located across three sites at Niwot Ridge, CO, ranging from near the lower limit of subalpine forest to alpine tundra. We use infrared heaters to raise growing season surface soil temperatures by 4-5°C, and to lengthen the growing season. The warming treatment is crossed with a soil moisture manipulation to distinguish effects due to higher temperatures from those due to drier soil. Each plot is a common garden sown with high and low elevation provenances of limber pine (Pinus flexilis) and Engelmann spruce (Picea engelmannii). We established an additional set of experimental plots to examine treatment effects on alpine species phenology, growth and reproduction. Under ambient conditions in 2009, tree seedling germination rate, lifespan, and first season survival was higher within the species’ current range than in the alpine, and for Engelmann spruce, was higher at the low elevation limit than the high elevation limit. Source population (low vs. high elevation) was a significant factor explaining natural variation in

  11. 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

  12. Analysis on the Causes of Low-point Displacement Anomaly in Daily Variation of Z Component of Geomagnetic Field%地磁Z分量日变"低点位移"异常成因分析

    Institute of Scientific and Technical Information of China (English)

    胡久常

    2011-01-01

    本文基于对地磁Z分量日变"低点位移"异常和太阳静日变化内外源场等效涡旋电流体系时空演化特征的分析,提出了"电磁炉效应"假说,以解释地磁Z分量日变"低点位移"异常的成因.本文认为,起源于地球内部和外部涡旋电流体系所产生的太阳静日变化Sq,作为一个持续的交变磁场,切割地壳深部的高导低速层,形成涡旋电流并产生热能,致使高导低速层温度和压力不断上升,最终突破临界状态产生物质相变,引起电导率快速变化,使内外源场单个等效涡旋电流体系分解成两个或多个涡旋电流体系,进而引起地磁Z分量日变的"低点位移"异常.%This paper analysed the characteristics of spatio-temporal evolving of low-point displacement anomaly and the intrinsic and extrinsic equivalent eddy electric current system of the Earth, and proposed the “electromagnetism effect of stove” to explain the cause of low-point displacement. Solar quiet daily variation(Sq), originated from the intrinsic and extrinsic eddy electric current system of the Earth, as an ongoing and alternating magnetic field, cutting the high conducting and low velocity block in the deep of crust, produces the eddy electric current, and creates heat energy. The heat energy results in the unceasingly rising of temperature and pressure, finally has the material phase transition, and causes the conductivity change, and also leads the eddy electric current system to evolve from single eddy electric current system to double and more eddy electric current system. This might be the cause of low-point displacement anomaly in daily variation of Z component of geomagnetic field.

  13. Quasi-periodic variations in the Doppler shift of HF signals scattered by artificial ionospheric turbulence

    Science.gov (United States)

    Belenov, A. F.; Ponomarenko, P. V.; Sinitsyn, V. G.; Yampol'Skii, Yu. M.

    1993-12-01

    The results of an experimental study of quasi-periodic variations of the Doppler shift (DS) of decimeter-wave signals scattered by artificial ionospheric turbulence are presented. It is suggested that ionospheric MHD waves of natural origin are a possible cause of such variations. The amplitude of the magnetic component of such waves that leads to observable values of DS variations is estimated to be 1γ.

  14. Quasi-periodic variations in the Doppler shift of HF signals scattered by artificial ionospheric turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Belenov, A.F.; Ponomarenko, P.V.; Sinitsyn, V.G.; Yampol`skii, Yu.M.

    1994-06-01

    The results of an experimental study of quasi-periodic variations of the Doppler shift (DS) of decimeter-wave signals scattered by artificial ionospheric turbulence are presented. It is suggested that ionospheric MHD waves of natural origin are a possible cause of such variations. The amplitude of the magnetic component of such waves that leads to observable values of DS variations is estimated to be 1{gamma}.

  15. 美国出口天然气的原因与影响%Causes and Effects On the US Natural Gas Exports

    Institute of Scientific and Technical Information of China (English)

    王鑫

    2015-01-01

    作为头号经济强国,美国的能源消费量居世界前列,其似乎不应出口能源产品。然而,受页岩气开采导致的天然气产量大增等因素影响,美国正计划大规模地出口液化天然气,美国能源部和联邦能源管理委员会已批准了一些液化天然气出口项目。在不久的将来,美国出口液化天然气必将对全球能源市场产生重大影响。%As the biggest economic country,energy consumption of the USA is among the first place in the world.Which seems it can’ t export energy products.However,because of the natural gas production surge resulting from shale gas exploitation and other factors, the USA is planning to export liquefied natural gas on a large scale,The United States Department of Energy and the Federal Energy Regulatory Commission have approved a number of liquefied natural gas export projects.In the near future,The USA exports of lique-fied natural gas will have a major impact on the global energy market.

  16. Determination of natural isotopic variation in antimony using inductively coupled plasma mass spectrometry for an uncertainty estimation of the standard atomic weight of antimony

    International Nuclear Information System (INIS)

    The isotopic variation of industrially produced antimony was estimated using multiple-collector inductively coupled plasma mass spectrometry. A reproducible 123Sb/121Sb ratio of ±0.004% (2 standard deviations) was routinely obtained using a Sn doping mass discrimination correction technique. Only a small isotopic variation of about 0.05% was observed among industrially important Sb materials (five commercially available reagents and two ore minerals). The degree of Sb isotopic variation to determine the uncertainty in Sb atomic weight can be reduced by this new analytical technique to 0.00025 compared to the currently accepted IUPAC isotopic variation determined by conventional mass spectrometry of ±0.001. Heavy isotope enrichment of Sb in a drainage water sample from a stibnite mining area was found. This heavy isotope enrichment tendency in an aqueous environment may be useful in detecting anthropogenic Sb input from industrial emission by the smelting process via air because Sb of anthropogenic origin will have lighter isotope enrichment features. (author)

  17. Carbon isotopes: variations of their natural abundance. Application to correction of radiocarbon dates, to the study of plant metabolism and to paleoclimate

    International Nuclear Information System (INIS)

    The radiocarbon activity of contemporaneous samples shows: i) variations in the specific activity of the atmospheric C14, which varies with time and locality. ii) variations due to isotope discrimination, or fractionation, of the carbon isotope ratio during the fixation of carbon by organic or inorganic matter. The variation in the atmospheric concentration of carbon 14 as observed in tree rings are synchronous and of the same amplitude for both hemispheres (southern and northern). A curve for correction of radiocarbon dates of the southern hemisphere is given for the last 500 years. The activity of atmospheric radiocarbon as measured in tree rings varies with latitude, showing a difference of (4.5+-1) per mille between the northern and southern hemispheres, the latter having lower concentration of radiocarbon, equivalent to an age difference of about 35 years. This variation can be explained by a larger exchange of carbon 14 between the atmosphere and the sea in the southern hemisphere to a larger free ocean surface (40%) and a higher agitation by winds. The main differences of the isotope fractionation by different types of plants are correlated to their photosynthetic pathways and thus to the enzyme which effects the primary fixation of carbon. The delta C13 values can be used as basis of a paleoclimate indicator

  18. Cause of Flu (Influenza)

    Science.gov (United States)

    ... Skip Content Marketing Share this: Main Content Area Flu (Influenza) Cause About the Flu Virus Influenza, or flu, is a respiratory infection ... the virus. Influenza A virus. Credit: CDC Where Influenza Comes From In nature, the flu virus is ...

  19. Variation of fundamental constants

    CERN Document Server

    Flambaum, V V

    2006-01-01

    We present a review of recent works devoted to the variation of the fine structure constant alpha, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra, Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feschbach resonance.

  20. Genetic Basis for Spontaneous Hybrid Genome Doubling during Allopolyploid Speciation of Common Wheat Shown by Natural Variation Analyses of the Paternal Species

    OpenAIRE

    Yoshihiro Matsuoka; Shuhei Nasuda; Yasuyo Ashida; Miyuki Nitta; Hisashi Tsujimoto; Shigeo Takumi; Taihachi Kawahara

    2013-01-01

    The complex process of allopolyploid speciation includes various mechanisms ranging from species crosses and hybrid genome doubling to genome alterations and the establishment of new allopolyploids as persisting natural entities. Currently, little is known about the genetic mechanisms that underlie hybrid genome doubling, despite the fact that natural allopolyploid formation is highly dependent on this phenomenon. We examined the genetic basis for the spontaneous genome doubling of triploid F...

  1. Energy crisis: contributions to reduce impacts on Rio de Janeiro state industry caused by shortage of natural gas supply; Crise energetica: contribuicoes para a reducao de impactos sobre a industria fluminense decorrente de um contingenciamento da oferta de gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Cristiano Prado M.; Silva, Tatiana Lauria Vieira da [Sistema FIRJAN, Rio de Janeiro, RJ (Brazil). Gerencia de Infra-estrutura e Novos Investimentos], e-mail: cpbarbosa@firjan.org.br, e-mail: tlsilva@firjan.org.br

    2008-07-01

    The scope of this paper is to discuss the main factors that pushed the increase of the industrial utilization of natural gas in Rio de Janeiro and the structural imbalance between supply and demand in this market on the second semester of 2007. The shortage in October 2007 brought uncertainty to the energetic supply to the industrial sector, and leaded to a crisis in January 2008. In order to evaluate the hindrances and to propose solutions aiming to prevent future crisis, the Federation of Industries of Rio de Janeiro - Sistema FIRJAN - did a research along with industries that represent the majority part of the industrial demand of natural gas in Rio de Janeiro. The main results show that the industries are inclined to adapt to this new reality by lowering the consumption of natural gas. Nonetheless, environmental, institutional and economic issues make it difficult, and sometimes impossible, to implement the change. Beyond mapping the Rio de Janeiro industry's consumption of natural gas, this paper calls for the necessity of a long-run energetic planning in order to face the challenges that are being posed to the natural gas chain. (author)

  2. Naturally occurring broad-spectrum powdery mildew resistance in a Central American tomato accession is caused by loss of mlo function.

    Science.gov (United States)

    Bai, Yuling; Pavan, Stefano; Zheng, Zheng; Zappel, Nana F; Reinstädler, Anja; Lotti, Concetta; De Giovanni, Claudio; Ricciardi, Luigi; Lindhout, Pim; Visser, Richard; Theres, Klaus; Panstruga, Ralph

    2008-01-01

    The resistant cherry tomato (Solanum lycopersicum var. cerasiforme) line LC-95, derived from an accession collected in Ecuador, harbors a natural allele (ol-2) that confers broad-spectrum and recessively inherited resistance to powdery mildew (Oidium neolycopersici). As both the genetic and phytopathological characteristics of ol-2-mediated resistance are reminiscent of powdery mildew immunity conferred by loss-of-function mlo alleles in barley and Arabidopsis, we initiated a candidate-gene approach to clone Ol-2. A tomato Mlo gene (SlMlo1) with high sequence-relatedness to barley Mlo and Arabidopsis AtMLO2 mapped to the chromosomal region harboring the Ol-2 locus. Complementation experiments using transgenic tomato lines as well as virus-induced gene silencing assays suggested that loss of SlMlo1 function is responsible for powdery mildew resistance conferred by ol-2. In progeny of a cross between a resistant line bearing ol-2 and the susceptible tomato cultivar Moneymaker, a 19-bp deletion disrupting the SlMlo1 coding region cosegregated with resistance. This polymorphism results in a frameshift and, thus, a truncated nonfunctional SlMlo1 protein. Our findings reveal the second example of a natural mlo mutant that possibly arose post-domestication, suggesting that natural mlo alleles might be evolutionarily short-lived due to fitness costs related to loss of mlo function. PMID:18052880

  3. William Bateson from Balanoglossus to Materials for the study of variation: the transatlantic roots of discontinuity and the (un)naturalness of selection.

    Science.gov (United States)

    Peterson, Erik L

    2008-01-01

    William Bateson (1861-1926) has long occupied a controversial role in the history of biology at the turn of the twentieth century. For the most part, Bateson has been situated as the British translator of Mendel or as the outspoken antagonist of W. F. R. Weldon and Karl Pearson's biometrics program. Less has been made of Bateson's transition from embryologist to advocate for discontinuous variation, and the precise role of British and American influences in that transition, in the years leading up to the publication of his massive Materials for the Study of Variation (1894). In this paper, I first attempt to trace Bateson's development in his early career before turning to search for the development of the moniker "anti-Darwinist" that has been attached to Bateson in well-known histories of the neo-Darwinian Synthesis. PMID:19049232

  4. Effectivity of water soluble granule from kenikir leaves extract (Cosmos caudatus), noni leaves extract (Morinda citrifolia), and earthworm meal extract (Lumbricus rubellus) as a natural coccidiostat for broiler chickens against infection caused by Eimeri

    OpenAIRE

    Karimy MF; Julendr H; Hayati SN; Sofyan a; Damayanti E; Priyowidodo D

    2013-01-01

    The aim of this research was to study effectivity of water soluble granule from kenikir leaves extract (Cosmos caudatus), noni leaves extract (Morinda citrifolia), and earthworm meal extract (Lumbricus rubellus) as a natural coccidiostat for broiler chickens against infection caused by Eimeria tenella. One hundred day old chick (DOC) of the Cobb strain broiler were randomly devided into 10 groups and each group consisted of 10 chickens. All groups were orally infected by 5000 sporulated oocys...

  5. Particles causing lung disease.

    OpenAIRE

    Kilburn, K H

    1984-01-01

    The lung has a limited number of patterns of reaction to inhaled particles. The disease observed depends upon the location: conducting airways, terminal bronchioles and alveoli, and upon the nature of inflammation induced: acute, subacute or chronic. Many different agents cause narrowing of conducting airways (asthma) and some of these cause permanent distortion or obliteration of airways as well. Terminal bronchioles appear to be particularly susceptible to particles which cause goblet cell ...

  6. Study of the variation of the efficiency of ∝ emitting sources as a function of the nature of the support and the applied threshold (1962)

    International Nuclear Information System (INIS)

    The effect of the sample holder nature of α emitters sources on their activity measurements was investigated. Obtention of ultra-thin sources (zero-thickness) was attempted and backscattering coefficient for α particles was measured for different sample support materials. (authors)

  7. Natural variation underlies alterations in Nramp aluminum transporter (NRAT1) expression and function that play a key role in rice aluminum tolerance

    Science.gov (United States)

    Aluminum (Al) toxicity is a major constraint for crop production on acid soils that comprise approximately 50% of arable land in the tropics and subtropics. Rice is the most Al tolerant cereal crop, and offers a good model for identifying Al tolerance genes and mechanisms. Here we investigated natur...

  8. Are Long-Distance Migrants Constrained in Their Evolutionary Response to Environmental Change?: Causes of Variation in the Timing of Autumn Migration in a Blackcap (S. atricapilla) and Two Garden Warbler (Sylvia borin) Populations

    NARCIS (Netherlands)

    Pulido, F.; Widmer, M.

    2005-01-01

    Long-distance migratory birds often show little phenotypic variation in the timing of life-history events like breeding, molt, or migration. It has been hypothesized that this could result from low levels of heritable variation. If this were true, the adaptability of long-distance migratory birds wo

  9. Study of a method of detection for natural carbon-14 using a liquid scintillator, recent variations in the natural radio-activity due to artificial carbon-14 (1963); Etude d'une methode de detection du carrons 14 naturel, utilisant un scintillateur liquide - variations recentes de l'activite naturelle dues au carbone 14 artificiel (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Leger, C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-06-15

    Among the various natural isotopes of carbon, a radioactive isotope, carbon-14, is formed by the action of secondary neutrons from cosmic rays on nitrogen in the air. Until 1950, the concentration of this isotope in ordinary carbon underwent weak fluctuations of about 2-3 per cent. The exact measurement of this concentration 6 X 10{sup 12} Ci/gm of carbon, and of its fluctuations, are difficult and in the first part of this report a highly sensitive method is given using a liquid scintillator. Since 1950 this natural activity has shown large fluctuations because of the carbon-14 formed during nuclear explosions, and in the second part, the evolution in France of this specific activity of carbon in the atmosphere and biosphere is examined. In the last part is studied the local increase in carbon activity in the atmosphere around the Saclay site, an increase caused by the carbon-14 given off as C{sup 14}O{sub 2}, by the reactors cooled partially with exterior air. (author) [French] Parmi les differents isotopes naturels du carbone, un isotope radioactif, le carbone 14, est forme par l'action de neutrons secondaires due aux rayons cosmiques sir l'azote de l'air. Jusqu'en 1950, la concentration de cet isotope dans le carbone ordinaire est soumise a des fluctuations de faible amplitude, de l'ordre de 2 a 3 pour cent. Les mesures precises de cette concentration, 6. 10{sup -12} Ci/g de carbone, et de ses fluctuations sont delicates, et dans la premiere partie de ce rapport, on decrit une methode de detection a grande sensibilite utilisant un scintillateur liquide. Depuis 1950, cette activite naturelle subit des fluctuations importantes dues au carbone 14 forme lors des explosions nucleaires, et dans la seconde partie, on examine l'evolution en France de l'activite specifique du carbone de l'atmosphere et ce la biosphere. Dans la derniere partie, on etudie l'accroissement local de l'activite du carbone de l'air aux

  10. 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. PMID:26710238

  11. Assessment of the variation of natural radioactivity in sands of Camburi beach, Vitoria, Epirito Santo, Brazil with climatological and geological factors of the region

    International Nuclear Information System (INIS)

    The main contribution to the external exposure to humans comes from gamma emitting radionuclides in soils, especially the 40K and 238U and 232Th series. In this work, the activity concentrations of 226Ra (238U series), 232Th and 40K in surface sand monthly collected at 11 sites along the Camburi beach during the year 2011, selected to cover the entire length of the beach, were determined. The samples were hermetically sealed and measured by high resolution gamma spectrometry, after a resting time of approximately 30 days, in order to attain the radioactive equilibrium in the 238U and 232Th series. The activity concentration of 226Ra was determined by the weighted average concentrations of 214Pb and 214Bi, the activity concentration of 232Th by the weighted average concentrations of 212Pb, 212Bi and 228Ac. The activity of 40K was determined by its single transition of 1460,8 keV. For all samples the concentrations were corrected by self attenuation factors. From these concentrations, radiological indices like radium equivalent activity (Raeq), activity concentration index (Iγ), external exposure risk index (Hext), internal exposure risk index (Hint), absorbed gamma dose rate in air (D) in nGy.h-1 and annual effective dose (E) in mSv.y-1 were evaluated. In the studied area it was realized an assessment of the correlation of the activity concentrations of 226Ra, 232Th and 40K with the geological, geographical, climatological (rainfall and temperature) and oceanographic (tidal height variation) factors. Due to the strong presence of monazite, the concentration of 232Th is higher than the concentration of 226Ra and 40K. The activity concentrations found ranged from 4 Bq.kg-1 to 1380 Bq.kg-1 for 226Ra, from 9 Bq.kg-1 to 7453 Bq.kg-1 for 232Th and 6 Bq.kg-1 to 504 Bq.kg-1 for 40K. The variation of Raeq from 20 Bq.kg-1 to 12077 Bq.kg-1, of Iγ from 0,07 to 42,08, of Hext from 0,05 to 32,61, of Hint from 0,06 to 36,34 and of absorbed gamma dose rate in air from 0,05 to 32

  12. 腹泻后高钾血症致窦室传导心电图演变一例报道%Sinus Ventricular Conduction ECG Variation Caused by Hyperkalemia after Diarrhea:A Case Report

    Institute of Scientific and Technical Information of China (English)

    王齐芳; 谢东阳; 龚春林

    2014-01-01

    In this paper,an old man presented with long -term and repeated dyspnea and edema of double lower limbs,sought medical advice due to recently developed diarrhea,palpitations and fatigue symptoms. Based on the results of rele-vant checks,the case was initial diagnosed as senile valvular heart disease,atrial fibrillation,cardiac insufficiency,prerenal renal insufficiency and hyperkalemia. The patient took long-term medication to treat heart disease. The initial symptom was diar-rhea,abnormal severe hyperkalemia was observed,which may due to the usage of drugs under the hydrated condition. Through the dynamic observation of ECG variation and supportive treatment,hyperkalemia was corrected,and ECG returned to the level before this onset. Diarrhea is a common clinical cause for hypokalemia. In this case,hyperkalemia caused by long-term cardiac insufficiency and diarrea is worthy of special attention in clinical treatment. After rehydration treatment,urinary output increased, serum potassium concentration gradually returned to normal,characteristic changes of ECG was observed. The case might be use-ful in teaching and learning.%本文报道了1例老年男性因长期反复呼吸困难伴双下肢水肿,近期出现腹泻、心悸乏力症状就诊,完善相关检查初步诊断为:老年退行性心脏瓣膜病,心房纤颤,心功能不全;肾前性肾功能不全;高钾血症。患者长期服用药物治疗心脏基础疾病,本次因腹泻起病,反常出现严重的高钾血症,分析可能与脱水状态下使用药物有关,动态观察心电图演变并对症支持治疗后纠正了高钾血症,心电图恢复到本次起病前水平。因腹泻起病,临床上引起低钾血症多见,本例因长期心功能不全,腹泻引起高钾血症,所以临床上治疗要特别注意。在补液增加尿量等治疗后,血钾逐渐恢复正常,心电图也呈特征性变化,具有一定的教学意义。

  13. Spatial variation of N-2-fixation in field pea (Pisum sativum L.) at the field scale determined by the N-15 natural abundance method

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, Henrik; Holdensen, Lars; Wulfsohn, D.; Jensen, Erik Steen

    in pea 15N natural abundance of 1 δ unit between flowering and maturity and a reference crop decline of 1.3 δ15N unit over the same period increased noise of derived variables, making modeling of N2-fixation difficult. Furthermore, complex interactions with other soil variables and biotic stresses...... not measured in this study may have contributed significantly to the variability of fixation and yield of pea within the field. Pea N2-fixation obtained from two additional 10 ha farmer fields was in agreement with the other findings highlighting that N2-fixation takes place under a range of physical...

  14. Natural variation in immune responses to neonatal Mycobacterium bovis Bacillus Calmette-Guerin (BCG Vaccination in a Cohort of Gambian infants.

    Directory of Open Access Journals (Sweden)

    Chris Finan

    Full Text Available BACKGROUND: There is a need for new vaccines for tuberculosis (TB that protect against adult pulmonary disease in regions where BCG is not effective. However, BCG could remain integral to TB control programmes because neonatal BCG protects against disseminated forms of childhood TB and many new vaccines rely on BCG to prime immunity or are recombinant strains of BCG. Interferon-gamma (IFN-gamma is required for immunity to mycobacteria and used as a marker of immunity when new vaccines are tested. Although BCG is widely given to neonates IFN-gamma responses to BCG in this age group are poorly described. Characterisation of IFN-gamma responses to BCG is required for interpretation of vaccine immunogenicity study data where BCG is part of the vaccination strategy. METHODOLOGY/PRINCIPAL FINDINGS: 236 healthy Gambian babies were vaccinated with M. bovis BCG at birth. IFN-gamma, interleukin (IL-5 and IL-13 responses to purified protein derivative (PPD, killed Mycobacterium tuberculosis (KMTB, M. tuberculosis short term culture filtrate (STCF and M. bovis BCG antigen 85 complex (Ag85 were measured in a whole blood assay two months after vaccination. Cytokine responses varied up to 10 log-fold within this population. The majority of infants (89-98% depending on the antigen made IFN-gamma responses and there was significant correlation between IFN-gamma responses to the different mycobacterial antigens (Spearman's coefficient ranged from 0.340 to 0.675, p = 10(-6-10(-22. IL-13 and IL-5 responses were generally low and there were more non-responders (33-75% for these cytokines. Nonetheless, significant correlations were observed for IL-13 and IL-5 responses to different mycobacterial antigens CONCLUSIONS/SIGNIFICANCE: Cytokine responses to mycobacterial antigens in BCG-vaccinated infants are heterogeneous and there is significant inter-individual variation. Further studies in large populations of infants are required to identify the factors that determine

  15. The AMMA-CATCH Gourma observatory site in Mali: Relating climatic variations to changes in vegetation, surface hydrology, fluxes and natural resources

    Science.gov (United States)

    Mougin, E.; Hiernaux, P.; Kergoat, L.; Grippa, M.; de Rosnay, P.; Timouk, F.; Le Dantec, V.; Demarez, V.; Lavenu, F.; Arjounin, M.; Lebel, T.; Soumaguel, N.; Ceschia, E.; Mougenot, B.; Baup, F.; Frappart, F.; Frison, P. L.; Gardelle, J.; Gruhier, C.; Jarlan, L.; Mangiarotti, S.; Sanou, B.; Tracol, Y.; Guichard, F.; Trichon, V.; Diarra, L.; Soumaré, A.; Koité, M.; Dembélé, F.; Lloyd, C.; Hanan, N. P.; Damesin, C.; Delon, C.; Serça, D.; Galy-Lacaux, C.; Seghieri, J.; Becerra, S.; Dia, H.; Gangneron, F.; Mazzega, P.

    2009-08-01

    SummaryThe Gourma site in Mali is one of the three instrumented meso-scale sites deployed in West-Africa as part of the African Monsoon Multi-disciplinary Analysis (AMMA) project. Located both in the Sahelian zone sensu stricto, and in the Saharo-Sahelian transition zone, the Gourma meso-scale window is the northernmost site of the AMMA-CATCH observatory reached by the West African Monsoon. The experimental strategy includes deployment of a variety of instruments, from local to meso-scale, dedicated to monitoring and documentation of the major variables characterizing the climate forcing, and the spatio-temporal variability of surface processes and state variables such as vegetation mass, leaf area index (LAI), soil moisture and surface fluxes. This paper describes the Gourma site, its associated instrumental network and the research activities that have been carried out since 1984. In the AMMA project, emphasis is put on the relations between climate, vegetation and surface fluxes. However, the Gourma site is also important for development and validation of satellite products, mainly due to the existence of large and relatively homogeneous surfaces. The social dimension of the water resource uses and governance is also briefly analyzed, relying on field enquiry and interviews. The climate of the Gourma region is semi-arid, daytime air temperatures are always high and annual rainfall amounts exhibit strong inter-annual and seasonal variations. Measurements sites organized along a north-south transect reveal sharp gradients in surface albedo, net radiation, vegetation production, and distribution of plant functional types. However, at any point along the gradient, surface energy budget, soil moisture and vegetation growth contrast between two main types of soil surfaces and hydrologic systems. On the one hand, sandy soils with high water infiltration rates and limited run-off support almost continuous herbaceous vegetation with scattered woody plants. On the other

  16. Seasonal variation of nutrients and energy in tambaqui's (Colossoma Macropomum Cuvier, 1818) natural food Variação sazonal de nutrientes e energia do alimento natural do tambaqui (Colossoma macropomum Cuvier, 1918)

    OpenAIRE

    J. A. M. da SILVA; PEREIRA-FILHO M.; M. I. de OLIVEIRA-PEREIRA

    2000-01-01

    The aim of this study was to evaluate the importance of fruits and seeds as food items in the natural diet of the tambaqui (Colossoma macropomum). During one year, tambaqui's stomach contents were collected, and their nutritional and energetic values were determined. During the flooding period, and while the river water was rising, which coincided with a high availability of fruits and seeds, the protein content of food was low (11%-15% of dry matter basis), whereas in the dry season, when ta...

  17. An Ecological Biogeographic Analysis of the Impacts of Climatic Variations and  Forest Fires on The Natural Environment, Nature Protection Areas and Biota in The Muğla District

    OpenAIRE

    Türkeş, Murat; ALTAN, Gökhan

    2013-01-01

    The Muğla district located at the southwest part of Turkey, which is characterized with typical features of the dry summer subtropical Mediterranean climate and the Mediterranean ecosystems, has hosted some of the important nature areas of Turkey. In another words, Muğla is one of the unique city provinces in Turkey by having the significant potential in terms of its diverse biotope (e.g. bays, lagoons, coastal and forest ecosystems, etc.), biota (flora and fauna), endemic and relict species,...

  18. Variational principles in physics

    CERN Document Server

    Basdevant, Jean-Louis

    2007-01-01

    Optimization under constraints is an essential part of everyday life. Indeed, we routinely solve problems by striking a balance between contradictory interests, individual desires and material contingencies. This notion of equilibrium was dear to thinkers of the enlightenment, as illustrated by Montesquieu’s famous formulation: "In all magistracies, the greatness of the power must be compensated by the brevity of the duration." Astonishingly, natural laws are guided by a similar principle. Variational principles have proven to be surprisingly fertile. For example, Fermat used variational methods to demonstrate that light follows the fastest route from one point to another, an idea which came to be known as Fermat’s principle, a cornerstone of geometrical optics. Variational Principles in Physics explains variational principles and charts their use throughout modern physics. The heart of the book is devoted to the analytical mechanics of Lagrange and Hamilton, the basic tools of any physicist. Prof. Basdev...

  19. Causas de variação nos preços de bovinos nelore elite no Brasil Causes of variation in the prices of nelore elite cattle in Brazil

    Directory of Open Access Journals (Sweden)

    João Cláudio do Carmo Paneto

    2009-02-01

    Full Text Available Este trabalho teve por objetivo estudar as causas de variação nos preços de bovinos da raça nelore pertencentes a rebanhos de seleção, os quais foram comercializados em leilões, para verificar as influências das avaliações genéticas e dos julgamentos de exterior sobre esses preços. Para tanto, foram computados os preços de venda de 426 bovinos da referida raça em 12 leilões ocorridos em diversas localidades brasileiras (regiões Centro-Oeste, Norte e Sudeste, entre os anos de 2002 e 2005. O valor médio foi de R$ 3.325,49, sendo o mínimo de R$ 1.400,00 e o máximo de R$ 10.500,00. Esses dados foram digitados juntamente com outras informações que eram apresentadas nos catálogos dos leilões. As informações registradas incluíram o sexo de cada animal, o nome do leilão e as DEPs informadas nos catálogos. Além da avaliação da influência das informações dos catálogos, também foi avaliada a influência das informações dos reprodutores, pais dos animais vendidos nos leilões, envolvendo suas DEPs publicadas em um sumário de reprodutores da raça e as pontuações de suas progênies em julgamentos. Os métodos estatísticos aplicados foram análises de variâncias e análises de agrupamento (método K-médias. Como resultado, foi observado que animais com superioridade genética em características relacionadas a desempenho ponderal, considerando-se os efeitos diretos e maternos, foram valorizados ao serem comercializados nos leilões. Em contra-partida, a pontuação dos reprodutores nos julgamentos não teve influência significativa sobre os preços médios de venda de suas progênies nos leilões.This study aimed to understand the causes of variation in the marketing prices of elite flock nelore cattle commercialized by auction, especially to verify the influences of EPDs and visual assessment. The selling prices of 426 animals from the nelore breed commercialized during 12 auctions held in various Brazilian

  20. Site characterization and validation - measurement of flowrate, solute velocities and aperture variation in natural fractures as a function of normal and shear stress, stage 3

    International Nuclear Information System (INIS)

    Laboratory tests have been completed on natural fracture planes in three, 200 mm diameter, cores, to determine the effect of changes in normal and shear stress on fracture permeability and porosity. In each core, a single fracture plane was oriented parallel to the core axis and the flow and tracer tests were completed under linear flow boundary conditions. At the completion of the full stressflow test cycle, the fracture plane was impregnated with resin and, after the resin had hardened, the fracture plane was sectioned and the structure of the pore space characterized. The test data showed that there is linear relationship between the logarithm of flowrate and the logarithm of normal stress. For shear tests on the two main samples, which were conducted at shear stresses less than the peak shear strength, the flowrates decreased slightly with increase in shear displacement. The porosities determined from the resin data and the fluid velocities determined from the tracer tests show that the volume of fluid in the fracture plane is much greater than that predicted using equivalent smooth parallel plate model. (authors)