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Sample records for show large variations

  1. Temporal Variation of Large Scale Flows in the Solar Interior ...

    Indian Academy of Sciences (India)

    tribpo

    Temporal Variation of Large Scale Flows in the Solar Interior. 355. Figure 2. Zonal and meridional components of the time-dependent residual velocity at a few selected depths as marked above each panel, are plotted as contours of constant velocity in the longitude-latitude plane. The left panels show the zonal component, ...

  2. Background levels of methane in Mars’ atmosphere show strong seasonal variations

    Science.gov (United States)

    Webster, Christopher R.; Mahaffy, Paul R.; Atreya, Sushil K.; Moores, John E.; Flesch, Gregory J.; Malespin, Charles; McKay, Christopher P.; Martinez, German; Smith, Christina L.; Martin-Torres, Javier; Gomez-Elvira, Javier; Zorzano, Maria-Paz; Wong, Michael H.; Trainer, Melissa G.; Steele, Andrew; Archer, Doug; Sutter, Brad; Coll, Patrice J.; Freissinet, Caroline; Meslin, Pierre-Yves; Gough, Raina V.; House, Christopher H.; Pavlov, Alexander; Eigenbrode, Jennifer L.; Glavin, Daniel P.; Pearson, John C.; Keymeulen, Didier; Christensen, Lance E.; Schwenzer, Susanne P.; Navarro-Gonzalez, Rafael; Pla-García, Jorge; Rafkin, Scot C. R.; Vicente-Retortillo, Álvaro; Kahanpää, Henrik; Viudez-Moreiras, Daniel; Smith, Michael D.; Harri, Ari-Matti; Genzer, Maria; Hassler, Donald M.; Lemmon, Mark; Crisp, Joy; Sander, Stanley P.; Zurek, Richard W.; Vasavada, Ashwin R.

    2018-06-01

    Variable levels of methane in the martian atmosphere have eluded explanation partly because the measurements are not repeatable in time or location. We report in situ measurements at Gale crater made over a 5-year period by the Tunable Laser Spectrometer on the Curiosity rover. The background levels of methane have a mean value 0.41 ± 0.16 parts per billion by volume (ppbv) (95% confidence interval) and exhibit a strong, repeatable seasonal variation (0.24 to 0.65 ppbv). This variation is greater than that predicted from either ultraviolet degradation of impact-delivered organics on the surface or from the annual surface pressure cycle. The large seasonal variation in the background and occurrences of higher temporary spikes (~7 ppbv) are consistent with small localized sources of methane released from martian surface or subsurface reservoirs.

  3. Characterization and potential functional significance of human-chimpanzee large INDEL variation

    Directory of Open Access Journals (Sweden)

    Polavarapu Nalini

    2011-10-01

    Full Text Available Abstract Background Although humans and chimpanzees have accumulated significant differences in a number of phenotypic traits since diverging from a common ancestor about six million years ago, their genomes are more than 98.5% identical at protein-coding loci. This modest degree of nucleotide divergence is not sufficient to explain the extensive phenotypic differences between the two species. It has been hypothesized that the genetic basis of the phenotypic differences lies at the level of gene regulation and is associated with the extensive insertion and deletion (INDEL variation between the two species. To test the hypothesis that large INDELs (80 to 12,000 bp may have contributed significantly to differences in gene regulation between the two species, we categorized human-chimpanzee INDEL variation mapping in or around genes and determined whether this variation is significantly correlated with previously determined differences in gene expression. Results Extensive, large INDEL variation exists between the human and chimpanzee genomes. This variation is primarily attributable to retrotransposon insertions within the human lineage. There is a significant correlation between differences in gene expression and large human-chimpanzee INDEL variation mapping in genes or in proximity to them. Conclusions The results presented herein are consistent with the hypothesis that large INDELs, particularly those associated with retrotransposons, have played a significant role in human-chimpanzee regulatory evolution.

  4. Multigrid solution of the Navier-Stokes equations at low speeds with large temperature variations

    International Nuclear Information System (INIS)

    Sockol, Peter M.

    2003-01-01

    Multigrid methods for the Navier-Stokes equations at low speeds and large temperature variations are investigated. The compressible equations with time-derivative preconditioning and preconditioned flux-difference splitting of the inviscid terms are used. Three implicit smoothers have been incorporated into a common multigrid procedure. Both full coarsening and semi-coarsening with directional fine-grid defect correction have been studied. The resulting methods have been tested on four 2D laminar problems over a range of Reynolds numbers on both uniform and highly stretched grids. Two of the three methods show efficient and robust performance over the entire range of conditions. In addition, none of the methods has any difficulty with the large temperature variations

  5. Seasonal variation of dystocia in a large Danish cohort.

    Science.gov (United States)

    Rohr Thomsen, Christine; Uldbjerg, Niels; Hvidman, Lone; Atladóttir, Hjördís Ósk; Henriksen, Tine Brink; Milidou, Ioanna

    2014-01-01

    Dystocia is one of the most frequent causes of cesarean delivery in nulliparous women. Despite this, its causes are largely unknown. Vitamin D receptor (VDR) has been found in the myometrium. Thus, it is possible that vitamin D affects the contractility of the myometrium and may be involved in the pathogenesis of dystocia. Seasonal variation of dystocia in areas with distinct seasonal variation in sunlight exposure, like Denmark, could imply that vitamin D may play a role. This study examined whether there was seasonal variation in the incidence of dystocia in a Danish population. We used information from a cohort of 34,261 nulliparous women with singleton pregnancies, spontaneous onset of labor between 37 and 42 completed gestational weeks, and vertex fetal presentation. All women gave birth between 1992 and 2010 at the Department of Obstetrics and Gynecology, Aarhus University Hospital, Skejby. Logistic regression combined with cubic spline was used to estimate the seasonal variation for each outcome after adjusting for calendar time. No evidence for seasonal variation was found for any of the outcomes: acute cesarean delivery due to dystocia (p = 0.44); instrumental vaginal delivery due to dystocia (p = 0.69); oxytocin augmentation due to dystocia (p = 0.46); and overall dystocia (p = 0.91). No seasonal variation in the incidence of dystocia was observed in a large cohort of Danish women. This may reflect no association between vitamin D and dystocia, or alternatively that other factors with seasonal variation and influence on the occurrence of dystocia attenuate such an association.

  6. Variation in the peacock's train shows a genetic component.

    Science.gov (United States)

    Petrie, Marion; Cotgreave, Peter; Pike, Thomas W

    2009-01-01

    Female peafowl (Pavo cristatus) show a strong mating preference for males with elaborate trains. This, however, poses something of a paradox because intense directional selection should erode genetic variation in the males' trains, so that females will no longer benefit by discriminating among males on the basis of these traits. This situation is known as the 'lek paradox', and leads to the theoretical expectation of low heritability in the peacock's train. We used two independent breeding experiments, involving a total of 42 sires and 86 of their male offspring, to estimate the narrow sense heritabilities of male ornaments and other morphometric traits. Contrary to expectation, we found significant levels of heritability in a trait known to be used by females during mate choice (train length), while no significant heritabilities were evident for other, non-fitness related morphological traits (tarsus length, body weight or spur length). This study adds to the building body of evidence that high levels of additive genetic variance can exist in secondary sexual traits under directional selection, but further emphasizes the main problem of what maintains this variation.

  7. Variation in thickness of the large cryosections cut for whole-body autoradiography

    International Nuclear Information System (INIS)

    Ito, Tsunao; Brill, A.B.

    1991-01-01

    A method to assess variation in thickness of the large cryosections for whole-body autoradiography (WBARG) was described, and the degree of intraslice and interslice variations were determined for our cryomicrotome system (LKB PMV-2250). Intraslice variation in thickness of the 180 x 80 mm cryosection was 0.72-0.92 μm within the range of section thickness for WBARG (15-50 μm), and interslice variation was 0.89-1.21 μm. These potential variations in section thickness should be kept in mind whenever working with quantitative WBARG. (author)

  8. Large observer variation of clinical assessment of dyspnoeic wheezing children.

    Science.gov (United States)

    Bekhof, Jolita; Reimink, Roelien; Bartels, Ine-Marije; Eggink, Hendriekje; Brand, Paul L P

    2015-07-01

    In children with acute dyspnoea, the assessment of severity of dyspnoea and response to treatment is often performed by different professionals, implying that knowledge of the interobserver variation of this clinical assessment is important. To determine intraobserver and interobserver variation in clinical assessment of children with dyspnoea. From September 2009 to September 2010, we recorded a convenience sample of 27 acutely wheezing children (aged 3 months-7 years) in the emergency department of a general teaching hospital in the Netherlands, on video before and after treatment with inhaled bronchodilators. These video recordings were independently assessed by nine observers scoring wheeze, prolonged expiratory phase, retractions, nasal flaring and a general assessment of dyspnoea on a Likert scale (0-10). Assessment was repeated after 2 weeks to evaluate intraobserver variation. We analysed 972 observations. Intraobserver reliability was the highest for supraclavicular retractions (κ 0.84) and moderate-to-substantial for other items (κ 0.49-0.65). Interobserver reliability was considerably worse, with κ3 points) was larger than the minimal important change (meaning that in 69% of observations a clinically important change after treatment cannot be distinguished from measurement error. Intraobserver variation is modest, and interobserver variation is large for most clinical findings in children with dyspnoea. The measurement error induced by this variation is too large to distinguish potentially clinically relevant changes in dyspnoea after treatment in two-thirds of observations. The poor interobserver reliability of clinical dyspnoea assessment in children limits its usefulness in clinical practice and research, and highlights the need to use more objective measurements in these patients. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  9. Listeria monocytogenes strains show large variations in competitive growth in mixed culture biofilms and suspensions with bacteria from food processing environments.

    Science.gov (United States)

    Heir, Even; Møretrø, Trond; Simensen, Andreas; Langsrud, Solveig

    2018-06-20

    Interactions and competition between resident bacteria in food processing environments could affect their ability to survive, grow and persist in microhabitats and niches in the food industry. In this study, the competitive ability of L. monocytogenes strains grown together in separate culture mixes with other L. monocytogenes (L. mono mix), L. innocua (Listeria mix), Gram-negative bacteria (Gram- mix) and with a multigenera mix (Listeria + Gram- mix) was investigated in biofilms on stainless steel and in suspensions at 12 °C. The mixed cultures included resident bacteria from processing surfaces in meat and salmon industry represented by L. monocytogenes (n = 6), L. innocua (n = 5) and Gram-negative bacteria (n = 6; Acinetobacter sp., Pseudomonas fragi, Pseudomonas fluorescens, Serratia liquefaciens, Stenotrophomonas maltophilia). Despite hampered in growth in mixed cultures, L. monocytogenes established in biofilms with counts at day nine between 7.3 and 9.0 log per coupon with the lowest counts in the Listeria + G- mix that was dominated by Pseudomonas. Specific L. innocua inhibited growth of L. monocytogenes strains differently; inhibition that was further enhanced by the background Gram-negative microbiota. In these multispecies and multibacteria cultures, the growth competitive effects lead to the dominance of a strong competitor L. monocytogenes strain that was only slightly inhibited by L. innocua and showed strong competitive abilities in mixed cultures with resident Gram-negative bacteria. The results indicates complex patterns of bacterial interactions and L. monocytogenes inhibition in the multibacteria cultures that only partially depend on cell contact and likely involve various antagonistic and bacterial tolerance mechanisms. The study indicates large variations among L. monocytogenes in their competitiveness under multibacterial culture conditions that should be considered in further studies towards understanding of L

  10. Variation in Surficial Hydrated Minerals on Large Low-Albedo Asteroids

    Science.gov (United States)

    Rivkin, Andrew S.; Emery, Joshua P.; Howell, Ellen S.

    2017-10-01

    Observations of asteroids in the 3-µm spectral region, where absorptions diagnostic for hydrated minerals are found, show low-albedo asteroid spectra can be classified into at least 3 groups (Takir et al. 2013, Rivkin et al. 2015). While definitions of these groups vary between authors, they hold in common a group with spectra like what we see for CM/CI meteorites, one group with spectra like that of Ceres, and a group with spectra that have been interpreted as ice frost. The relationship between these groups is not yet clear. One possibility is that the spectrum reflects (no pun intended) the formation location for the asteroids and that a given object is undifferentiated and homogeneous in the composition of its hydrated minerals. However, models of the thermal and chemical evolution of large, low-albedo asteroids suggests that differentiation may be more common than we had thought, and impacts could exhume once-deep layers or expose complicated mixes of salts and silicates (for instance, Castillo-Rogez et al. LPSC 2017 model of Ceres). In this case, we might expect variation in the 3-µm spectral region to be seen on the surfaces of some objects as they rotate. We will present evidence for such variation in the spectrum of two large asteroids, 704 Interamnia (306 km diameter) and 324 Bamberga (220 km diameter). In the first case, Interamnia’s spectrum seems to have a combination of Ceres- and CM/CI-like features and has aspects where one or another component is dominant, while Bamberga’s spectrum is not easily placed in previously-defined groups.

  11. Survey Shows Variation in Ph.D. Methods Training.

    Science.gov (United States)

    Steeves, Leslie; And Others

    1983-01-01

    Reports on a 1982 survey of journalism graduate studies indicating considerable variation in research methods requirements and emphases in 23 universities offering doctoral degrees in mass communication. (HOD)

  12. The wild tomato species Solanum chilense shows variation in pathogen resistance between geographically distinct populations.

    Science.gov (United States)

    Stam, Remco; Scheikl, Daniela; Tellier, Aurélien

    2017-01-01

    Wild tomatoes are a valuable source of disease resistance germplasm for tomato ( Solanum lycopersicum ) breeders. Many species are known to possess a certain degree of resistance against certain pathogens; however, evolution of resistance traits is yet poorly understood. For some species, like Solanum chilense , both differences in habitat and within species genetic diversity are very large. Here we aim to investigate the occurrence of spatially heterogeneous coevolutionary pressures between populations of S. chilense . We investigate the phenotypic differences in disease resistance within S. chilense against three common tomato pathogens ( Alternaria solani , Phytophthora infestans and a Fusarium sp .) and confirm high degrees of variability in resistance properties between selected populations. Using generalised linear mixed models, we show that disease resistance does not follow the known demographic patterns of the species. Models with up to five available climatic and geographic variables are required to best describe resistance differences, confirming the complexity of factors involved in local resistance variation. We confirm that within S. chilense , resistance properties against various pathogens show a mosaic pattern and do not follow environmental patterns, indicating the strength of local pathogen pressures. Our study can form the basis for further investigations of the genetic traits involved.

  13. The intertidal community in West Greenland: Large-scale patterns and small-scale variation on ecosystem dynamics along a climate gradient

    DEFF Research Database (Denmark)

    Thyrring, Jakob; Blicher, Martin; Sejr, Mikael Kristian

    are largely unknown. The West Greenland coast is north - south orientated. This provides an ideal setting to study the impact of climate change on marine species population dynamics and distribution. We investigated the latitudinal changes in the rocky intertidal community along 18° latitudes (59-77°N......) in West Greenland. Using cleared quadrats we quantified patterns in abundance, biomass and species richness in the intertidal zone. We use this data to disentangle patterns in Arctic intertidal communities at different scales. We describe the effects of different environmental drivers and species...... interactions on distribution and dynamics of intertidal species. Our results indicate that changes in distribution and abundance of foundation species can have large effects on the ecosystem. We also show that the importance of small-scale variation may be of same magnitude as large- scale variation. Only...

  14. Stability of Grid-Connected PV Inverters with Large Grid Impedance Variation

    DEFF Research Database (Denmark)

    Liserre, Marco; Teodorescu, Remus; Blaabjerg, Frede

    2004-01-01

    Photovoltaic (PV) inverters used in dispersed power generation of houses in the range of 1-5 kW are currently available from several manufactures. However, large grid impedance variation is challenging the control and the grid filter design in terms of stability. In fact the PV systems are well...... suited for loads connected in a great distance to the transformer (long wires) and the situation becomes even more difficult in low-developed remote areas characterized by low power transformers and long distribution wires with high grid impedance. Hence a theoretical analysis is needed because the grid...... impedance variation leads to dynamic and stability problems both in the low frequency range (around the current controller bandwidth frequency) as well as in the high frequency range (around the LCL-filter resonance frequency). In the low frequency range the possible variation of the impedance challenges...

  15. The wild tomato species Solanum chilense shows variation in pathogen resistance between geographically distinct populations

    Directory of Open Access Journals (Sweden)

    Remco Stam

    2017-01-01

    Full Text Available Wild tomatoes are a valuable source of disease resistance germplasm for tomato (Solanum lycopersicum breeders. Many species are known to possess a certain degree of resistance against certain pathogens; however, evolution of resistance traits is yet poorly understood. For some species, like Solanum chilense, both differences in habitat and within species genetic diversity are very large. Here we aim to investigate the occurrence of spatially heterogeneous coevolutionary pressures between populations of S. chilense. We investigate the phenotypic differences in disease resistance within S. chilense against three common tomato pathogens (Alternaria solani, Phytophthora infestans and a Fusarium sp. and confirm high degrees of variability in resistance properties between selected populations. Using generalised linear mixed models, we show that disease resistance does not follow the known demographic patterns of the species. Models with up to five available climatic and geographic variables are required to best describe resistance differences, confirming the complexity of factors involved in local resistance variation. We confirm that within S. chilense, resistance properties against various pathogens show a mosaic pattern and do not follow environmental patterns, indicating the strength of local pathogen pressures. Our study can form the basis for further investigations of the genetic traits involved.

  16. The wild tomato species Solanum chilense shows variation in pathogen resistance between geographically distinct populations

    Science.gov (United States)

    Scheikl, Daniela; Tellier, Aurélien

    2017-01-01

    Wild tomatoes are a valuable source of disease resistance germplasm for tomato (Solanum lycopersicum) breeders. Many species are known to possess a certain degree of resistance against certain pathogens; however, evolution of resistance traits is yet poorly understood. For some species, like Solanum chilense, both differences in habitat and within species genetic diversity are very large. Here we aim to investigate the occurrence of spatially heterogeneous coevolutionary pressures between populations of S. chilense. We investigate the phenotypic differences in disease resistance within S. chilense against three common tomato pathogens (Alternaria solani, Phytophthora infestans and a Fusarium sp.) and confirm high degrees of variability in resistance properties between selected populations. Using generalised linear mixed models, we show that disease resistance does not follow the known demographic patterns of the species. Models with up to five available climatic and geographic variables are required to best describe resistance differences, confirming the complexity of factors involved in local resistance variation. We confirm that within S. chilense, resistance properties against various pathogens show a mosaic pattern and do not follow environmental patterns, indicating the strength of local pathogen pressures. Our study can form the basis for further investigations of the genetic traits involved. PMID:28133579

  17. Sensitivity of the scale partition for variational multiscale large-eddy simulation of channel flow

    NARCIS (Netherlands)

    Holmen, J.; Hughes, T.J.R.; Oberai, A.A.; Wells, G.N.

    2004-01-01

    The variational multiscale method has been shown to perform well for large-eddy simulation (LES) of turbulent flows. The method relies upon a partition of the resolved velocity field into large- and small-scale components. The subgrid model then acts only on the small scales of motion, unlike

  18. Patterns of variations in large pelagic fish: A comparative approach between the Indian and the Atlantic Oceans

    Science.gov (United States)

    Corbineau, A.; Rouyer, T.; Fromentin, J.-M.; Cazelles, B.; Fonteneau, A.; Ménard, F.

    2010-07-01

    Catch data of large pelagic fish such as tuna, swordfish and billfish are highly variable ranging from short to long term. Based on fisheries data, these time series are noisy and reflect mixed information on exploitation (targeting, strategy, fishing power), population dynamics (recruitment, growth, mortality, migration, etc.), and environmental forcing (local conditions or dominant climate patterns). In this work, we investigated patterns of variation of large pelagic fish (i.e. yellowfin tuna, bigeye tuna, swordfish and blue marlin) in Japanese longliners catch data from 1960 to 2004. We performed wavelet analyses on the yearly time series of each fish species in each biogeographic province of the tropical Indian and Atlantic Oceans. In addition, we carried out cross-wavelet analyses between these biological time series and a large-scale climatic index, i.e. the Southern Oscillation Index (SOI). Results showed that the biogeographic province was the most important factor structuring the patterns of variability of Japanese catch time series. Relationships between the SOI and the fish catches in the Indian and Atlantic Oceans also pointed out the role of climatic variability for structuring patterns of variation of catch time series. This work finally confirmed that Japanese longline CPUE data poorly reflect the underlying population dynamics of tunas.

  19. A microsatellite linkage map for Drosophila montana shows large variation in recombination rates, and a courtship song trait maps to an area of low recombination.

    Science.gov (United States)

    Schäfer, M A; Mazzi, D; Klappert, K; Kauranen, H; Vieira, J; Hoikkala, A; Ritchie, M G; Schlötterer, C

    2010-03-01

    Current advances in genetic analysis are opening up our knowledge of the genetics of species differences, but challenges remain, particularly for out-bred natural populations. We constructed a microsatellite-based linkage map for two out-bred lines of Drosophila montana derived from divergent populations by taking advantage of the Drosophila virilis genome and available cytological maps of both species. Although the placement of markers was quite consistent with cytological predictions, the map indicated large heterogeneity in recombination rates along chromosomes. We also performed a quantitative trait locus (QTL) analysis on a courtship song character (carrier frequency), which differs between populations and is subject to strong sexual selection. Linkage mapping yielded two significant QTLs, which explained 3% and 14% of the variation in carrier frequency, respectively. Interestingly, as in other recent studies of traits which can influence speciation, the strongest QTL mapped to a genomic region partly covered by an inversion polymorphism.

  20. 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.

  1. Azimuthal angle correlations at large rapidities. Revisiting density variation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Gotsman, E. [Tel Aviv University, Department of Particle Physics, Raymond and Beverly Sackler Faculty of Exact Science, School of Physics and Astronomy, Tel Aviv (Israel); Levin, E. [Tel Aviv University, Department of Particle Physics, Raymond and Beverly Sackler Faculty of Exact Science, School of Physics and Astronomy, Tel Aviv (Israel); Universidad Tecnica Federico Santa Maria, Departemento de Fisica, Valparaiso (Chile); Centro Cientifico-Tecnologico de Valparaiso, Valparaiso (Chile)

    2017-11-15

    We discuss the angular correlation present in hadron-hadron collisions at large rapidity difference (anti α{sub S}y{sub 12} >> 1). We find that in the CGC/saturation approach the largest contribution stems from the density variation mechanism. Our principal results are that the odd Fourier harmonics (v{sub 2n+1}) decrease substantially as a function of y{sub 12}, while the even harmonics (v{sub 2n}) increase considerably with the growth of y{sub 12}. (orig.)

  2. Large-Scale No-Show Patterns and Distributions for Clinic Operational Research

    Directory of Open Access Journals (Sweden)

    Michael L. Davies

    2016-02-01

    Full Text Available Patient no-shows for scheduled primary care appointments are common. Unused appointment slots reduce patient quality of care, access to services and provider productivity while increasing loss to follow-up and medical costs. This paper describes patterns of no-show variation by patient age, gender, appointment age, and type of appointment request for six individual service lines in the United States Veterans Health Administration (VHA. This retrospective observational descriptive project examined 25,050,479 VHA appointments contained in individual-level records for eight years (FY07-FY14 for 555,183 patients. Multifactor analysis of variance (ANOVA was performed, with no-show rate as the dependent variable, and gender, age group, appointment age, new patient status, and service line as factors. The analyses revealed that males had higher no-show rates than females to age 65, at which point males and females exhibited similar rates. The average no-show rates decreased with age until 75–79, whereupon rates increased. As appointment age increased, males and new patients had increasing no-show rates. Younger patients are especially prone to no-show as appointment age increases. These findings provide novel information to healthcare practitioners and management scientists to more accurately characterize no-show and attendance rates and the impact of certain patient factors. Future general population data could determine whether findings from VHA data generalize to others.

  3. Large-Scale No-Show Patterns and Distributions for Clinic Operational Research.

    Science.gov (United States)

    Davies, Michael L; Goffman, Rachel M; May, Jerrold H; Monte, Robert J; Rodriguez, Keri L; Tjader, Youxu C; Vargas, Dominic L

    2016-02-16

    Patient no-shows for scheduled primary care appointments are common. Unused appointment slots reduce patient quality of care, access to services and provider productivity while increasing loss to follow-up and medical costs. This paper describes patterns of no-show variation by patient age, gender, appointment age, and type of appointment request for six individual service lines in the United States Veterans Health Administration (VHA). This retrospective observational descriptive project examined 25,050,479 VHA appointments contained in individual-level records for eight years (FY07-FY14) for 555,183 patients. Multifactor analysis of variance (ANOVA) was performed, with no-show rate as the dependent variable, and gender, age group, appointment age, new patient status, and service line as factors. The analyses revealed that males had higher no-show rates than females to age 65, at which point males and females exhibited similar rates. The average no-show rates decreased with age until 75-79, whereupon rates increased. As appointment age increased, males and new patients had increasing no-show rates. Younger patients are especially prone to no-show as appointment age increases. These findings provide novel information to healthcare practitioners and management scientists to more accurately characterize no-show and attendance rates and the impact of certain patient factors. Future general population data could determine whether findings from VHA data generalize to others.

  4. Evidence from northwest European bogs shows ‘Little Ice Age’ climatic changes driven by variations in solar activity

    NARCIS (Netherlands)

    Mauquoy, D; van Geel, B; Blaauw, Maarten; van der Plicht, J

    2002-01-01

    Fluctuations in Holocene atmospheric radiocarbon concentrations have been shown to be due to variations in solar activity. Analyses of both Be-10 and C-14 nuclides confirm that production-rate changes during the Holocene were largely modulated by solar activity. Analyses of peat samples from two

  5. Spatial variations in food web structures with alternative stable states: evidence from stable isotope analysis in a large eutrophic lake

    Science.gov (United States)

    Li, Yunkai; Zhang, Yuying; Xu, Jun; Zhang, Shuo

    2018-03-01

    Food web structures are well known to vary widely among ecosystems. Moreover, many food web studies of lakes have generally attempted to characterize the overall food web structure and have largely ignored internal spatial and environmental variations. In this study, we hypothesize that there is a high degree of spatial heterogeneity within an ecosystem and such heterogeneity may lead to strong variations in environmental conditions and resource availability, in turn resulting in different trophic pathways. Stable carbon and nitrogen isotopes were employed for the whole food web to describe the structure of the food web in different sub-basins within Taihu Lake. This lake is a large eutrophic freshwater lake that has been intensively managed and highly influenced by human activities for more than 50 years. The results show significant isotopic differences between basins with different environmental characteristics. Such differences likely result from isotopic baseline differences combining with a shift in food web structure. Both are related to local spatial heterogeneity in nutrient loading in waters. Such variation should be explicitly considered in future food web studies and ecosystem-based management in this lake ecosystem.

  6. Spatial variations in food web structures with alternative stable states: evidence from stable isotope analysis in a large eutrophic lake

    Science.gov (United States)

    Li, Yunkai; Zhang, Yuying; Xu, Jun; Zhang, Shuo

    2017-05-01

    Food web structures are well known to vary widely among ecosystems. Moreover, many food web studies of lakes have generally attempted to characterize the overall food web structure and have largely ignored internal spatial and environmental variations. In this study, we hypothesize that there is a high degree of spatial heterogeneity within an ecosystem and such heterogeneity may lead to strong variations in environmental conditions and resource availability, in turn resulting in different trophic pathways. Stable carbon and nitrogen isotopes were employed for the whole food web to describe the structure of the food web in different sub-basins within Taihu Lake. This lake is a large eutrophic freshwater lake that has been intensively managed and highly influenced by human activities for more than 50 years. The results show significant isotopic differences between basins with different environmental characteristics. Such differences likely result from isotopic baseline differences combining with a shift in food web structure. Both are related to local spatial heterogeneity in nutrient loading in waters. Such variation should be explicitly considered in future food web studies and ecosystem-based management in this lake ecosystem.

  7. Variation in the macrofaunal community over large temporal and spatial scales in the southern Yellow Sea

    Science.gov (United States)

    Xu, Yong; Sui, Jixing; Yang, Mei; Sun, Yue; Li, Xinzheng; Wang, Hongfa; Zhang, Baolin

    2017-09-01

    To detect large, temporal- and spatial-scale variations in the macrofaunal community in the southern Yellow Sea, data collected along the western, middle and eastern regions of the southern Yellow Sea from 1958 to 2014 were organized and analyzed. Statistical methods such as cluster analysis, non-metric multidimensional scaling ordination (nMDS), permutational multivariate analysis of variance (PERMANOVA), redundancy analysis (RDA) and canonical correspondence analysis (CCA) were applied. The abundance of polychaetes increased in the western region but decreased in the eastern region from 1958 to 2014, whereas the abundance of echinoderms showed an opposite trend. For the entire macrofaunal community, Margalef's richness (d), the Shannon-Wiener index (H‧) and Pielou's evenness (J‧) were significantly lower in the eastern region when compared with the other two regions. No significant temporal differences were found for d and H‧, but there were significantly lower values of J‧ in 2014. Considerable variation in the macrofaunal community structure over the past several decades and among the geographical regions at the species, genus and family levels were observed. The species, genera and families that contributed to the temporal variation in each region were also identified. The most conspicuous pattern was the increase in the species Ophiura sarsii vadicola in the eastern region. In the western region, five polychaetes (Ninoe palmata, Notomastus latericeus, Paralacydonia paradoxa, Paraprionospio pinnata and Sternaspis scutata) increased consistently from 1958 to 2014. The dominance curves showed that both the species diversity and the dominance patterns were relatively stable in the western and middle regions. Environmental parameters such as depth, temperature and salinity could only partially explain the observed biological variation in the southern Yellow Sea. Anthropogenic activities such as demersal fishing and other unmeasured environmental variables

  8. Humans and Deep Networks Largely Agree on Which Kinds of Variation Make Object Recognition Harder.

    Science.gov (United States)

    Kheradpisheh, Saeed R; Ghodrati, Masoud; Ganjtabesh, Mohammad; Masquelier, Timothée

    2016-01-01

    View-invariant object recognition is a challenging problem that has attracted much attention among the psychology, neuroscience, and computer vision communities. Humans are notoriously good at it, even if some variations are presumably more difficult to handle than others (e.g., 3D rotations). Humans are thought to solve the problem through hierarchical processing along the ventral stream, which progressively extracts more and more invariant visual features. This feed-forward architecture has inspired a new generation of bio-inspired computer vision systems called deep convolutional neural networks (DCNN), which are currently the best models for object recognition in natural images. Here, for the first time, we systematically compared human feed-forward vision and DCNNs at view-invariant object recognition task using the same set of images and controlling the kinds of transformation (position, scale, rotation in plane, and rotation in depth) as well as their magnitude, which we call "variation level." We used four object categories: car, ship, motorcycle, and animal. In total, 89 human subjects participated in 10 experiments in which they had to discriminate between two or four categories after rapid presentation with backward masking. We also tested two recent DCNNs (proposed respectively by Hinton's group and Zisserman's group) on the same tasks. We found that humans and DCNNs largely agreed on the relative difficulties of each kind of variation: rotation in depth is by far the hardest transformation to handle, followed by scale, then rotation in plane, and finally position (much easier). This suggests that DCNNs would be reasonable models of human feed-forward vision. In addition, our results show that the variation levels in rotation in depth and scale strongly modulate both humans' and DCNNs' recognition performances. We thus argue that these variations should be controlled in the image datasets used in vision research.

  9. Humans and deep networks largely agree on which kinds of variation make object recognition harder

    Directory of Open Access Journals (Sweden)

    Saeed Reza Kheradpisheh

    2016-08-01

    Full Text Available View-invariant object recognition is a challenging problem that has attracted much attention among the psychology, neuroscience, and computer vision communities. Humans are notoriously good at it, even if some variations are presumably more difficult to handle than others (e.g. 3D rotations. Humans are thought to solve the problem through hierarchical processing along the ventral stream, which progressively extracts more and more invariant visual features. This feed-forward architecture has inspired a new generation of bio-inspired computer vision systems called deep convolutional neural networks (DCNN, which are currently the best models for object recognition in natural images. Here, for the first time, we systematically compared human feed-forward vision and DCNNs at view-invariant object recognition task using the same set of images and controlling the kinds of transformation (position, scale, rotation in plane, and rotation in depth as well as their magnitude, which we call variation level. We used four object categories: car, ship, motorcycle, and animal. In total, 89 human subjects participated in 10 experiments in which they had to discriminate between two or four categories after rapid presentation with backward masking. We also tested two recent DCNNs (proposed respectively by Hinton's group and Zisserman's group on the same tasks. We found that humans and DCNNs largely agreed on the relative difficulties of each kind of variation: rotation in depth is by far the hardest transformation to handle, followed by scale, then rotation in plane, and finally position (much easier. This suggests that DCNNs would be reasonable models of human feed-forward vision. In addition, our results show that the variation levels in rotation in depth and scale strongly modulate both humans' and DCNNs' recognition performances. We thus argue that these variations should be controlled in the image datasets used in vision research.

  10. PGen: large-scale genomic variations analysis workflow and browser in SoyKB.

    Science.gov (United States)

    Liu, Yang; Khan, Saad M; Wang, Juexin; Rynge, Mats; Zhang, Yuanxun; Zeng, Shuai; Chen, Shiyuan; Maldonado Dos Santos, Joao V; Valliyodan, Babu; Calyam, Prasad P; Merchant, Nirav; Nguyen, Henry T; Xu, Dong; Joshi, Trupti

    2016-10-06

    With the advances in next-generation sequencing (NGS) technology and significant reductions in sequencing costs, it is now possible to sequence large collections of germplasm in crops for detecting genome-scale genetic variations and to apply the knowledge towards improvements in traits. To efficiently facilitate large-scale NGS resequencing data analysis of genomic variations, we have developed "PGen", an integrated and optimized workflow using the Extreme Science and Engineering Discovery Environment (XSEDE) high-performance computing (HPC) virtual system, iPlant cloud data storage resources and Pegasus workflow management system (Pegasus-WMS). The workflow allows users to identify single nucleotide polymorphisms (SNPs) and insertion-deletions (indels), perform SNP annotations and conduct copy number variation analyses on multiple resequencing datasets in a user-friendly and seamless way. We have developed both a Linux version in GitHub ( https://github.com/pegasus-isi/PGen-GenomicVariations-Workflow ) and a web-based implementation of the PGen workflow integrated within the Soybean Knowledge Base (SoyKB), ( http://soykb.org/Pegasus/index.php ). Using PGen, we identified 10,218,140 single-nucleotide polymorphisms (SNPs) and 1,398,982 indels from analysis of 106 soybean lines sequenced at 15X coverage. 297,245 non-synonymous SNPs and 3330 copy number variation (CNV) regions were identified from this analysis. SNPs identified using PGen from additional soybean resequencing projects adding to 500+ soybean germplasm lines in total have been integrated. These SNPs are being utilized for trait improvement using genotype to phenotype prediction approaches developed in-house. In order to browse and access NGS data easily, we have also developed an NGS resequencing data browser ( http://soykb.org/NGS_Resequence/NGS_index.php ) within SoyKB to provide easy access to SNP and downstream analysis results for soybean researchers. PGen workflow has been optimized for the most

  11. Bayesian Image Restoration Using a Large-Scale Total Patch Variation Prior

    Directory of Open Access Journals (Sweden)

    Yang Chen

    2011-01-01

    Full Text Available Edge-preserving Bayesian restorations using nonquadratic priors are often inefficient in restoring continuous variations and tend to produce block artifacts around edges in ill-posed inverse image restorations. To overcome this, we have proposed a spatial adaptive (SA prior with improved performance. However, this SA prior restoration suffers from high computational cost and the unguaranteed convergence problem. Concerning these issues, this paper proposes a Large-scale Total Patch Variation (LS-TPV Prior model for Bayesian image restoration. In this model, the prior for each pixel is defined as a singleton conditional probability, which is in a mixture prior form of one patch similarity prior and one weight entropy prior. A joint MAP estimation is thus built to ensure the iteration monotonicity. The intensive calculation of patch distances is greatly alleviated by the parallelization of Compute Unified Device Architecture(CUDA. Experiments with both simulated and real data validate the good performance of the proposed restoration.

  12. Large variation in lipid content, ΣPCB and δ13C within individual Atlantic salmon (Salmo salar)

    International Nuclear Information System (INIS)

    Persson, Maria E.; Larsson, Per; Holmqvist, Niklas; Stenroth, Patrik

    2007-01-01

    Many studies that investigate pollutant levels, or use stable isotope ratios to define trophic level or animal origin, use different standard ways of sampling (dorsal, whole filet or whole body samples). This study shows that lipid content, ΣPCB and δ 13 C display large differences within muscle samples taken from a single Atlantic salmon. Lipid- and PCB-content was lowest in tail muscles, intermediate in anterior-dorsal muscles and highest in the stomach (abdominal) muscle area. Stable isotopes of carbon (δ 13 C) showed a lipid accumulation in the stomach muscle area and a depletion in tail muscles. We conclude that it is important to choose an appropriate sample location within an animal based on what processes are to be studied. Care should be taken when attributing persistent pollutant levels or stable isotope data to specific environmental processes before controlling for within-animal variation in these variables. - Lipid content, ΣPCB and δ 13 C vary to a large extent within Atlantic salmon, therefore, the sample technique for individual fish is of outmost importance for proper interpretation of data

  13. Large trees drive forest aboveground biomass variation in moist lowland forests across the tropics

    DEFF Research Database (Denmark)

    Slik, J.W.Ferry; Paoli, Gary; McGuire, Krista

    2013-01-01

    .3 ± 109.3 Mg ha−1). Pan-tropical variation in density of large trees and AGB was associated with soil coarseness (negative), soil fertility (positive), community wood density (positive) and dominance of wind dispersed species (positive), temperature in the coldest month (negative), temperature...

  14. Large-scale genomic analysis shows association between homoplastic genetic variation in Mycobacterium tuberculosis genes and meningeal or pulmonary tuberculosis.

    NARCIS (Netherlands)

    Ruesen, Carolien; Chaidir, Lidya; van Laarhoven, Arjan; Dian, Sofiati; Ganiem, Ahmad Rizal; Nebenzahl-Guimaraes, Hanna; Huynen, Martijn A; Alisjahbana, Bachti; Dutilh, Bas E; van Crevel, Reinout

    2018-01-01

    Meningitis is the most severe manifestation of tuberculosis. It is largely unknown why some people develop pulmonary TB (PTB) and others TB meningitis (TBM); we examined if the genetic background of infecting M. tuberculosis strains may be relevant.

  15. Cone-Beam Computed Tomography–Guided Positioning of Laryngeal Cancer Patients with Large Interfraction Time Trends in Setup and Nonrigid Anatomy Variations

    International Nuclear Information System (INIS)

    Gangsaas, Anne; Astreinidou, Eleftheria; Quint, Sandra; Levendag, Peter C.; Heijmen, Ben

    2013-01-01

    Purpose: To investigate interfraction setup variations of the primary tumor, elective nodes, and vertebrae in laryngeal cancer patients and to validate protocols for cone beam computed tomography (CBCT)-guided correction. Methods and Materials: For 30 patients, CBCT-measured displacements in fractionated treatments were used to investigate population setup errors and to simulate residual setup errors for the no action level (NAL) offline protocol, the extended NAL (eNAL) protocol, and daily CBCT acquisition with online analysis and repositioning. Results: Without corrections, 12 of 26 patients treated with radical radiation therapy would have experienced a gradual change (time trend) in primary tumor setup ≥4 mm in the craniocaudal (CC) direction during the fractionated treatment (11/12 in caudal direction, maximum 11 mm). Due to these trends, correction of primary tumor displacements with NAL resulted in large residual CC errors (required margin 6.7 mm). With the weekly correction vector adjustments in eNAL, the trends could be largely compensated (CC margin 3.5 mm). Correlation between movements of the primary and nodal clinical target volumes (CTVs) in the CC direction was poor (r 2 =0.15). Therefore, even with online setup corrections of the primary CTV, the required CC margin for the nodal CTV was as large as 6.8 mm. Also for the vertebrae, large time trends were observed for some patients. Because of poor CC correlation (r 2 =0.19) between displacements of the primary CTV and the vertebrae, even with daily online repositioning of the vertebrae, the required CC margin around the primary CTV was 6.9 mm. Conclusions: Laryngeal cancer patients showed substantial interfraction setup variations, including large time trends, and poor CC correlation between primary tumor displacements and motion of the nodes and vertebrae (internal tumor motion). These trends and nonrigid anatomy variations have to be considered in the choice of setup verification protocol and

  16. Canopy area of large trees explains aboveground biomass variations across neotropical forest landscapes

    Science.gov (United States)

    Meyer, Victoria; Saatchi, Sassan; Clark, David B.; Keller, Michael; Vincent, Grégoire; Ferraz, António; Espírito-Santo, Fernando; d'Oliveira, Marcus V. N.; Kaki, Dahlia; Chave, Jérôme

    2018-06-01

    Large tropical trees store significant amounts of carbon in woody components and their distribution plays an important role in forest carbon stocks and dynamics. Here, we explore the properties of a new lidar-derived index, the large tree canopy area (LCA) defined as the area occupied by canopy above a reference height. We hypothesize that this simple measure of forest structure representing the crown area of large canopy trees could consistently explain the landscape variations in forest volume and aboveground biomass (AGB) across a range of climate and edaphic conditions. To test this hypothesis, we assembled a unique dataset of high-resolution airborne light detection and ranging (lidar) and ground inventory data in nine undisturbed old-growth Neotropical forests, of which four had plots large enough (1 ha) to calibrate our model. We found that the LCA for trees greater than 27 m (˜ 25-30 m) in height and at least 100 m2 crown size in a unit area (1 ha), explains more than 75 % of total forest volume variations, irrespective of the forest biogeographic conditions. When weighted by average wood density of the stand, LCA can be used as an unbiased estimator of AGB across sites (R2 = 0.78, RMSE = 46.02 Mg ha-1, bias = -0.63 Mg ha-1). Unlike other lidar-derived metrics with complex nonlinear relations to biomass, the relationship between LCA and AGB is linear and remains unique across forest types. A comparison with tree inventories across the study sites indicates that LCA correlates best with the crown area (or basal area) of trees with diameter greater than 50 cm. The spatial invariance of the LCA-AGB relationship across the Neotropics suggests a remarkable regularity of forest structure across the landscape and a new technique for systematic monitoring of large trees for their contribution to AGB and changes associated with selective logging, tree mortality and other types of tropical forest disturbance and dynamics.

  17. Large Interstellar Polarisation Survey. II. UV/optical study of cloud-to-cloud variations of dust in the diffuse ISM

    Science.gov (United States)

    Siebenmorgen, R.; Voshchinnikov, N. V.; Bagnulo, S.; Cox, N. L. J.; Cami, J.; Peest, C.

    2018-03-01

    It is well known that the dust properties of the diffuse interstellar medium exhibit variations towards different sight-lines on a large scale. We have investigated the variability of the dust characteristics on a small scale, and from cloud-to-cloud. We use low-resolution spectro-polarimetric data obtained in the context of the Large Interstellar Polarisation Survey (LIPS) towards 59 sight-lines in the Southern Hemisphere, and we fit these data using a dust model composed of silicate and carbon particles with sizes from the molecular to the sub-micrometre domain. Large (≥6 nm) silicates of prolate shape account for the observed polarisation. For 32 sight-lines we complement our data set with UVES archive high-resolution spectra, which enable us to establish the presence of single-cloud or multiple-clouds towards individual sight-lines. We find that the majority of these 35 sight-lines intersect two or more clouds, while eight of them are dominated by a single absorbing cloud. We confirm several correlations between extinction and parameters of the Serkowski law with dust parameters, but we also find previously undetected correlations between these parameters that are valid only in single-cloud sight-lines. We find that interstellar polarisation from multiple-clouds is smaller than from single-cloud sight-lines, showing that the presence of a second or more clouds depolarises the incoming radiation. We find large variations of the dust characteristics from cloud-to-cloud. However, when we average a sufficiently large number of clouds in single-cloud or multiple-cloud sight-lines, we always retrieve similar mean dust parameters. The typical dust abundances of the single-cloud cases are [C]/[H] = 92 ppm and [Si]/[H] = 20 ppm.

  18. Full-Scale Modeling Explaining Large Spatial Variations of Nitrous Oxide Fluxes in a Step-Feed Plug-Flow Wastewater Treatment Reactor.

    Science.gov (United States)

    Ni, Bing-Jie; Pan, Yuting; van den Akker, Ben; Ye, Liu; Yuan, Zhiguo

    2015-08-04

    Nitrous oxide (N2O) emission data collected from wastewater treatment plants (WWTPs) show huge variations between plants and within one plant (both spatially and temporarily). Such variations and the relative contributions of various N2O production pathways are not fully understood. This study applied a previously established N2O model incorporating two currently known N2O production pathways by ammonia-oxidizing bacteria (AOB) (namely the AOB denitrification and the hydroxylamine pathways) and the N2O production pathway by heterotrophic denitrifiers to describe and provide insights into the large spatial variations of N2O fluxes in a step-feed full-scale activated sludge plant. The model was calibrated and validated by comparing simulation results with 40 days of N2O emission monitoring data as well as other water quality parameters from the plant. The model demonstrated that the relatively high biomass specific nitrogen loading rate in the Second Step of the reactor was responsible for the much higher N2O fluxes from this section. The results further revealed the AOB denitrification pathway decreased and the NH2OH oxidation pathway increased along the path of both Steps due to the increasing dissolved oxygen concentration. The overall N2O emission from this step-feed WWTP would be largely mitigated if 30% of the returned sludge were returned to the Second Step to reduce its biomass nitrogen loading rate.

  19. Photographic Records Showing the Variations of the Virtual Height of Reflection as a Function of the Radio Frequency

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standard (analog) ionosonde produces photographic records known as ionograms, which show the variations of the virtual height of reflection as a function of the...

  20. Size variation in Middle Pleistocene humans.

    Science.gov (United States)

    Arsuaga, J L; Carretero, J M; Lorenzo, C; Gracia, A; Martínez, I; Bermúdez de Castro, J M; Carbonell, E

    1997-08-22

    It has been suggested that European Middle Pleistocene humans, Neandertals, and prehistoric modern humans had a greater sexual dimorphism than modern humans. Analysis of body size variation and cranial capacity variation in the large sample from the Sima de los Huesos site in Spain showed instead that the sexual dimorphism is comparable in Middle Pleistocene and modern populations.

  1. Seasonal variation in the mating system of a selfing annual with large floral displays.

    Science.gov (United States)

    Yin, Ge; Barrett, Spencer C H; Luo, Yi-Bo; Bai, Wei-Ning

    2016-03-01

    Flowering plants display considerable variation in mating system, specifically the relative frequency of cross- and self-fertilization. The majority of estimates of outcrossing rate do not account for temporal variation, particularly during the flowering season. Here, we investigated seasonal variation in mating and fertility in Incarvillea sinensis (Bignoniaceae), an annual with showy, insect-pollinated, 'one-day' flowers capable of delayed selfing. We examined the influence of several biotic and abiotic environmental factors on day-to-day variation in fruit set, seed set and patterns of mating. We recorded daily flower number and pollinator abundance in nine 3 × 3-m patches in a population at Mu Us Sand land, Inner Mongolia, China. From marked flowers we collected data on daily fruit and seed set and estimated outcrossing rate and biparental inbreeding using six microsatellite loci and 172 open-pollinated families throughout the flowering period. Flower density increased significantly over most of the 50-d flowering season, but was associated with a decline in levels of pollinator service by bees, particularly on windy days. Fruit and seed set declined over time, especially during the latter third of the flowering period. Multilocus estimates of outcrossing rate were obtained using two methods (the programs MLTR and BORICE) and both indicated high selfing rates of ∼80 %. There was evidence for a significant increase in levels of selfing as the flowering season progressed and pollinator visitation declined. Biparental inbreeding also declined significantly as the flowering season progressed. Temporal variation in outcrossing rates may be a common feature of the mating biology of annual, insect-pollinated plants of harsh environments but our study is the first to examine seasonal mating-system dynamics in this context. Despite having large flowers and showy floral displays, I. sinensis attracted relatively few pollinators. Delayed selfing by corolla dragging

  2. Ulysses: accurate detection of low-frequency structural variations in large insert-size sequencing libraries.

    Science.gov (United States)

    Gillet-Markowska, Alexandre; Richard, Hugues; Fischer, Gilles; Lafontaine, Ingrid

    2015-03-15

    The detection of structural variations (SVs) in short-range Paired-End (PE) libraries remains challenging because SV breakpoints can involve large dispersed repeated sequences, or carry inherent complexity, hardly resolvable with classical PE sequencing data. In contrast, large insert-size sequencing libraries (Mate-Pair libraries) provide higher physical coverage of the genome and give access to repeat-containing regions. They can thus theoretically overcome previous limitations as they are becoming routinely accessible. Nevertheless, broad insert size distributions and high rates of chimerical sequences are usually associated to this type of libraries, which makes the accurate annotation of SV challenging. Here, we present Ulysses, a tool that achieves drastically higher detection accuracy than existing tools, both on simulated and real mate-pair sequencing datasets from the 1000 Human Genome project. Ulysses achieves high specificity over the complete spectrum of variants by assessing, in a principled manner, the statistical significance of each possible variant (duplications, deletions, translocations, insertions and inversions) against an explicit model for the generation of experimental noise. This statistical model proves particularly useful for the detection of low frequency variants. SV detection performed on a large insert Mate-Pair library from a breast cancer sample revealed a high level of somatic duplications in the tumor and, to a lesser extent, in the blood sample as well. Altogether, these results show that Ulysses is a valuable tool for the characterization of somatic mosaicism in human tissues and in cancer genomes. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  3. Oligocene sea water temperatures offshore Wilkes Land (Antarctica) indicate warm and stable glacial-interglacial variation and show no 'late Oligocene warming'

    Science.gov (United States)

    Hartman, Julian; Bijl, Peter; Peterse, Francien; Schouten, Stefan; Salabarnada, Ariadna; Bohaty, Steven; Escutia, Carlota; Brinkhuis, Henk; Sangiorgi, Francesca

    2017-04-01

    At present, warming of the waters below the Antarctic ice shelves is a major contributor to the instability of the Antarctic cryosphere. In order to get insight into future melt behavior of the Antarctic ice sheet, it is important to look at past warm periods that can serve as an analogue for the future. The Oligocene ( 34-23 Ma) is a period within the range of CO2 concentrations predicted by the latest IPCC report for the coming century and is characterized by a very dynamic Antarctic ice sheet, as suggested by benthic δ18O records from ice-distal sites. We suspect that, like today, environmental changes in the Southern Ocean are in part responsible for this dynamicity. To gain more insight into this, we have reconstructed sea water temperatures (SWT) based on Thaumarchaeotal lipids (TEX86) for the Oligocene record obtained from the ice-proximal Site U1356 (Integrated Ocean Drilling Program), offshore Wilkes Land. Part of our record shows a strong coupling between the lithology and SWT, which we attribute to glacial-interglacial variation. Our data shows that both glacial and interglacial temperatures are relatively warm throughout the Oligocene: 14°C and 18°C respectively, which is consistent with previously published estimates based on UK'37 and clumped isotopes for the early Oligocene. Our SST records show only a minor decline between 30 and 24 Ma, and thus show no evidence for a 'late Oligocene warming' as was suggested based on benthic δ18O records from low latitudes. Instead, the discrepancy between our SST trend and the δ18O trend suggests that the late-Oligocene benthic δ18O decrease is likely related to a decline in ice volume. After 24 Ma, however, glacial-interglacial temperature variation appears to increase. In particular, some large temperature drops occur, one of which can be related to the Mi-1 event and a major expansion of the Antarctic ice sheet.

  4. An Ensemble Three-Dimensional Constrained Variational Analysis Method to Derive Large-Scale Forcing Data for Single-Column Models

    Science.gov (United States)

    Tang, Shuaiqi

    Atmospheric vertical velocities and advective tendencies are essential as large-scale forcing data to drive single-column models (SCM), cloud-resolving models (CRM) and large-eddy simulations (LES). They cannot be directly measured or easily calculated with great accuracy from field measurements. In the Atmospheric Radiation Measurement (ARM) program, a constrained variational algorithm (1DCVA) has been used to derive large-scale forcing data over a sounding network domain with the aid of flux measurements at the surface and top of the atmosphere (TOA). We extend the 1DCVA algorithm into three dimensions (3DCVA) along with other improvements to calculate gridded large-scale forcing data. We also introduce an ensemble framework using different background data, error covariance matrices and constraint variables to quantify the uncertainties of the large-scale forcing data. The results of sensitivity study show that the derived forcing data and SCM simulated clouds are more sensitive to the background data than to the error covariance matrices and constraint variables, while horizontal moisture advection has relatively large sensitivities to the precipitation, the dominate constraint variable. Using a mid-latitude cyclone case study in March 3rd, 2000 at the ARM Southern Great Plains (SGP) site, we investigate the spatial distribution of diabatic heating sources (Q1) and moisture sinks (Q2), and show that they are consistent with the satellite clouds and intuitive structure of the mid-latitude cyclone. We also evaluate the Q1 and Q2 in analysis/reanalysis, finding that the regional analysis/reanalysis all tend to underestimate the sub-grid scale upward transport of moist static energy in the lower troposphere. With the uncertainties from large-scale forcing data and observation specified, we compare SCM results and observations and find that models have large biases on cloud properties which could not be fully explained by the uncertainty from the large-scale forcing

  5. Large-scale geographical variation in eggshell metal and calcium content in a passerine bird (Ficedula hypoleuca).

    Science.gov (United States)

    Ruuskanen, Suvi; Laaksonen, Toni; Morales, Judith; Moreno, Juan; Mateo, Rafael; Belskii, Eugen; Bushuev, Andrey; Järvinen, Antero; Kerimov, Anvar; Krams, Indrikis; Morosinotto, Chiara; Mänd, Raivo; Orell, Markku; Qvarnström, Anna; Slate, Fred; Tilgar, Vallo; Visser, Marcel E; Winkel, Wolfgang; Zang, Herwig; Eeva, Tapio

    2014-03-01

    Birds have been used as bioindicators of pollution, such as toxic metals. Levels of pollutants in eggs are especially interesting, as developing birds are more sensitive to detrimental effects of pollutants than adults. Only very few studies have monitored intraspecific, large-scale variation in metal pollution across a species' breeding range. We studied large-scale geographic variation in metal levels in the eggs of a small passerine, the pied flycatcher (Ficedula hypoleuca), sampled from 15 populations across Europe. We measured 10 eggshell elements (As, Cd, Cr, Cu, Ni, Pb, Zn, Se, Sr, and Ca) and several shell characteristics (mass, thickness, porosity, and color). We found significant variation among populations in eggshell metal levels for all metals except copper. Eggshell lead, zinc, and chromium levels decreased from central Europe to the north, in line with the gradient in pollution levels over Europe, thus suggesting that eggshell can be used as an indicator of pollution levels. Eggshell lead levels were also correlated with soil lead levels and pH. Most of the metals were not correlated with eggshell characteristics, with the exception of shell mass, or with breeding success, which may suggest that birds can cope well with the current background exposure levels across Europe.

  6. Utilising identifier error variation in linkage of large administrative data sources

    Directory of Open Access Journals (Sweden)

    Katie Harron

    2017-02-01

    Full Text Available Abstract Background Linkage of administrative data sources often relies on probabilistic methods using a set of common identifiers (e.g. sex, date of birth, postcode. Variation in data quality on an individual or organisational level (e.g. by hospital can result in clustering of identifier errors, violating the assumption of independence between identifiers required for traditional probabilistic match weight estimation. This potentially introduces selection bias to the resulting linked dataset. We aimed to measure variation in identifier error rates in a large English administrative data source (Hospital Episode Statistics; HES and to incorporate this information into match weight calculation. Methods We used 30,000 randomly selected HES hospital admissions records of patients aged 0–1, 5–6 and 18–19 years, for 2011/2012, linked via NHS number with data from the Personal Demographic Service (PDS; our gold-standard. We calculated identifier error rates for sex, date of birth and postcode and used multi-level logistic regression to investigate associations with individual-level attributes (age, ethnicity, and gender and organisational variation. We then derived: i weights incorporating dependence between identifiers; ii attribute-specific weights (varying by age, ethnicity and gender; and iii organisation-specific weights (by hospital. Results were compared with traditional match weights using a simulation study. Results Identifier errors (where values disagreed in linked HES-PDS records or missing values were found in 0.11% of records for sex and date of birth and in 53% of records for postcode. Identifier error rates differed significantly by age, ethnicity and sex (p < 0.0005. Errors were less frequent in males, in 5–6 year olds and 18–19 year olds compared with infants, and were lowest for the Asian ethic group. A simulation study demonstrated that substantial bias was introduced into estimated readmission rates in the presence

  7. Genome size variation affects song attractiveness in grasshoppers: evidence for sexual selection against large genomes.

    Science.gov (United States)

    Schielzeth, Holger; Streitner, Corinna; Lampe, Ulrike; Franzke, Alexandra; Reinhold, Klaus

    2014-12-01

    Genome size is largely uncorrelated to organismal complexity and adaptive scenarios. Genetic drift as well as intragenomic conflict have been put forward to explain this observation. We here study the impact of genome size on sexual attractiveness in the bow-winged grasshopper Chorthippus biguttulus. Grasshoppers show particularly large variation in genome size due to the high prevalence of supernumerary chromosomes that are considered (mildly) selfish, as evidenced by non-Mendelian inheritance and fitness costs if present in high numbers. We ranked male grasshoppers by song characteristics that are known to affect female preferences in this species and scored genome sizes of attractive and unattractive individuals from the extremes of this distribution. We find that attractive singers have significantly smaller genomes, demonstrating that genome size is reflected in male courtship songs and that females prefer songs of males with small genomes. Such a genome size dependent mate preference effectively selects against selfish genetic elements that tend to increase genome size. The data therefore provide a novel example of how sexual selection can reinforce natural selection and can act as an agent in an intragenomic arms race. Furthermore, our findings indicate an underappreciated route of how choosy females could gain indirect benefits. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  8. Spatial variation in messaging effects

    Science.gov (United States)

    Warshaw, Christopher

    2018-05-01

    There is large geographic variation in the public's views about climate change in the United States. Research now shows that climate messages can influence public beliefs about the scientific consensus on climate change, particularly in the places that are initially more skeptical.

  9. Annual variation in the net longshore sediment transport rate

    CSIR Research Space (South Africa)

    Schoonees, JS

    2000-05-01

    Full Text Available The annual variation in the net long shore sediment transport rates at three South African and at one North African site is investigated. The net rates at these sites, given in the first table, showed large variations. It was found that measurements...

  10. Model-based diagnosis of large diesel engines based on angular speed variations of the crankshaft

    Science.gov (United States)

    Desbazeille, M.; Randall, R. B.; Guillet, F.; El Badaoui, M.; Hoisnard, C.

    2010-07-01

    This work aims at monitoring large diesel engines by analyzing the crankshaft angular speed variations. It focuses on a powerful 20-cylinder diesel engine with crankshaft natural frequencies within the operating speed range. First, the angular speed variations are modeled at the crankshaft free end. This includes modeling both the crankshaft dynamical behavior and the excitation torques. As the engine is very large, the first crankshaft torsional modes are in the low frequency range. A model with the assumption of a flexible crankshaft is required. The excitation torques depend on the in-cylinder pressure curve. The latter is modeled with a phenomenological model. Mechanical and combustion parameters of the model are optimized with the help of actual data. Then, an automated diagnosis based on an artificially intelligent system is proposed. Neural networks are used for pattern recognition of the angular speed waveforms in normal and faulty conditions. Reference patterns required in the training phase are computed with the model, calibrated using a small number of actual measurements. Promising results are obtained. An experimental fuel leakage fault is successfully diagnosed, including detection and localization of the faulty cylinder, as well as the approximation of the fault severity.

  11. Explaining health care expenditure variation: large-sample evidence using linked survey and health administrative data.

    Science.gov (United States)

    Ellis, Randall P; Fiebig, Denzil G; Johar, Meliyanni; Jones, Glenn; Savage, Elizabeth

    2013-09-01

    Explaining individual, regional, and provider variation in health care spending is of enormous value to policymakers but is often hampered by the lack of individual level detail in universal public health systems because budgeted spending is often not attributable to specific individuals. Even rarer is self-reported survey information that helps explain this variation in large samples. In this paper, we link a cross-sectional survey of 267 188 Australians age 45 and over to a panel dataset of annual healthcare costs calculated from several years of hospital, medical and pharmaceutical records. We use this data to distinguish between cost variations due to health shocks and those that are intrinsic (fixed) to an individual over three years. We find that high fixed expenditures are positively associated with age, especially older males, poor health, obesity, smoking, cancer, stroke and heart conditions. Being foreign born, speaking a foreign language at home and low income are more strongly associated with higher time-varying expenditures, suggesting greater exposure to adverse health shocks. Copyright © 2013 John Wiley & Sons, Ltd.

  12. Large-scale geographical variation in eggshell heavy metal and calcium content in a passerine bird (Ficedula hypoleuca)

    NARCIS (Netherlands)

    Ruuskanen, S.; Morales, J.; Laaksonen, T.; Moreno, J.; Mateo, R.; Belskii, E.; Bushuev, A.; Jarvinen, A.; Kerimov, A.; Krams, I.; Morosinotto, C.; Mand, R.; Orell, M.; Qvarnstrom, A.; Slater, F.M.; Siitari, H.; Tilgar, V.; Visser, M.E.; Winkel, W.; Zang, H.; Eeva, T.

    2014-01-01

    Birds have been used as bioindicators of pollution, such as toxic metals. Levels of pollutants in eggs are especially interesting, as developing birds are more sensitive to detrimental effects of pollutants than adults. Only very few studies have monitored intraspecific, large-scale variation in

  13. Increased risk for diabetes development in subjects with large variation in total cholesterol levels in 2,827,950 Koreans: A nationwide population-based study.

    Directory of Open Access Journals (Sweden)

    Eun-Jung Rhee

    Full Text Available Recent studies suggest a role for hyperlipidemia in the development of diabetes. The aim of this study is to analyze the relationship between variations of total cholesterol (TC levels and the risk for type 2 diabetes development from a Korean nationwide population-based database.We examined the General Health Check-up sub-dataset of the Korean National Health Insurance Service (NHIS of 2,827,950 participants who had at least three health check-ups between 2002 and 2007, and were not reported to have diabetes during that time. The variations of TC levels between the examinations were calculated as follows: [Formula: see text]. The examinees were divided into 10 groups according to TC variation, and the hazard ratio for diabetes development from 2007 to 2013, were analyzed.During the follow-up period, 3.4% of the participants had developed diabetes. The hazard ratio (HR for diabetes development relative to the overall risk in the whole study population started to be higher than 1.0 from eighth decile of TC variation. The highest decile group showed an increased HR for diabetes development after adjustment for confounding variables (1.139; 95% confidence interval 1.116~1.163. These results were similar regardless of the use of anti-hyperlipidemic medication and baseline TC levels.The participants with a large variation in TC levels showed an increased risk for diabetes development, independent of the use of anti-hyperlipidemic medications. These results suggest a relationship between fluctuations in lipid levels and the development of type 2 diabetes.

  14. Solution of problems in calculus of variations via He's variational iteration method

    International Nuclear Information System (INIS)

    Tatari, Mehdi; Dehghan, Mehdi

    2007-01-01

    In the modeling of a large class of problems in science and engineering, the minimization of a functional is appeared. Finding the solution of these problems needs to solve the corresponding ordinary differential equations which are generally nonlinear. In recent years He's variational iteration method has been attracted a lot of attention of the researchers for solving nonlinear problems. This method finds the solution of the problem without any discretization of the equation. Since this method gives a closed form solution of the problem and avoids the round off errors, it can be considered as an efficient method for solving various kinds of problems. In this research He's variational iteration method will be employed for solving some problems in calculus of variations. Some examples are presented to show the efficiency of the proposed technique

  15. Large earthquake rupture process variations on the Middle America megathrust

    Science.gov (United States)

    Ye, Lingling; Lay, Thorne; Kanamori, Hiroo

    2013-11-01

    The megathrust fault between the underthrusting Cocos plate and overriding Caribbean plate recently experienced three large ruptures: the August 27, 2012 (Mw 7.3) El Salvador; September 5, 2012 (Mw 7.6) Costa Rica; and November 7, 2012 (Mw 7.4) Guatemala earthquakes. All three events involve shallow-dipping thrust faulting on the plate boundary, but they had variable rupture processes. The El Salvador earthquake ruptured from about 4 to 20 km depth, with a relatively large centroid time of ˜19 s, low seismic moment-scaled energy release, and a depleted teleseismic short-period source spectrum similar to that of the September 2, 1992 (Mw 7.6) Nicaragua tsunami earthquake that ruptured the adjacent shallow portion of the plate boundary. The Costa Rica and Guatemala earthquakes had large slip in the depth range 15 to 30 km, and more typical teleseismic source spectra. Regional seismic recordings have higher short-period energy levels for the Costa Rica event relative to the El Salvador event, consistent with the teleseismic observations. A broadband regional waveform template correlation analysis is applied to categorize the focal mechanisms for larger aftershocks of the three events. Modeling of regional wave spectral ratios for clustered events with similar mechanisms indicates that interplate thrust events have corner frequencies, normalized by a reference model, that increase down-dip from anomalously low values near the Middle America trench. Relatively high corner frequencies are found for thrust events near Costa Rica; thus, variations along strike of the trench may also be important. Geodetic observations indicate trench-parallel motion of a forearc sliver extending from Costa Rica to Guatemala, and low seismic coupling on the megathrust has been inferred from a lack of boundary-perpendicular strain accumulation. The slip distributions and seismic radiation from the large regional thrust events indicate relatively strong seismic coupling near Nicoya, Costa

  16. Detecting Significant Stress Drop Variations in Large Micro-Earthquake Datasets: A Comparison Between a Convergent Step-Over in the San Andreas Fault and the Ventura Thrust Fault System, Southern California

    Science.gov (United States)

    Goebel, T. H. W.; Hauksson, E.; Plesch, A.; Shaw, J. H.

    2017-06-01

    A key parameter in engineering seismology and earthquake physics is seismic stress drop, which describes the relative amount of high-frequency energy radiation at the source. To identify regions with potentially significant stress drop variations, we perform a comparative analysis of source parameters in the greater San Gorgonio Pass (SGP) and Ventura basin (VB) in southern California. The identification of physical stress drop variations is complicated by large data scatter as a result of attenuation, limited recording bandwidth and imprecise modeling assumptions. In light of the inherently high uncertainties in single stress drop measurements, we follow the strategy of stacking large numbers of source spectra thereby enhancing the resolution of our method. We analyze more than 6000 high-quality waveforms between 2000 and 2014, and compute seismic moments, corner frequencies and stress drops. Significant variations in stress drop estimates exist within the SGP area. Moreover, the SGP also exhibits systematically higher stress drops than VB and shows more scatter. We demonstrate that the higher scatter in SGP is not a generic artifact of our method but an expression of differences in underlying source processes. Our results suggest that higher differential stresses, which can be deduced from larger focal depth and more thrust faulting, may only be of secondary importance for stress drop variations. Instead, the general degree of stress field heterogeneity and strain localization may influence stress drops more strongly, so that more localized faulting and homogeneous stress fields favor lower stress drops. In addition, higher loading rates, for example, across the VB potentially result in stress drop reduction whereas slow loading rates on local fault segments within the SGP region result in anomalously high stress drop estimates. Our results show that crustal and fault properties systematically influence earthquake stress drops of small and large events and should

  17. Global Climate Forcing from Albedo Change Caused by Large-scale Deforestation and Reforestation: Quantification and Attribution of Geographic Variation

    Science.gov (United States)

    Jiao, Tong; Williams, Christopher A.; Ghimire, Bardan; Masek, Jeffrey; Gao, Feng; Schaaf, Crystal

    2017-01-01

    Large-scale deforestation and reforestation have contributed substantially to historical and contemporary global climate change in part through albedo-induced radiative forcing, with meaningful implications for forest management aiming to mitigate climate change. Associated warming or cooling varies widely across the globe due to a range of factors including forest type, snow cover, and insolation, but resulting geographic variation remain spoorly described and has been largely based on model assessments. This study provides an observation-based approach to quantify local and global radiative forcings from large-scale deforestation and reforestation and further examines mechanisms that result in the spatial heterogeneity of radiative forcing. We incorporate a new spatially and temporally explicit land cover-specific albedo product derived from Moderate Resolution Imaging Spectroradiometer with a historical land use data set (Land Use Harmonization product). Spatial variation in radiative forcing was attributed to four mechanisms, including the change in snow-covered albedo, change in snow-free albedo, snow cover fraction, and incoming solar radiation. We find an albedo-only radiative forcing (RF) of -0.819 W m(exp -2) if year 2000 forests were completely deforested and converted to croplands. Albedo RF from global reforestation of present-day croplands to recover year 1700 forests is estimated to be 0.161 W m)exp -2). Snow-cover fraction is identified as the primary factor in determining the spatial variation of radiative forcing in winter, while the magnitude of the change in snow-free albedo is the primary factor determining variations in summertime RF. Findings reinforce the notion that, for conifers at the snowier high latitudes, albedo RF diminishes the warming from forest loss and the cooling from forest gain more so than for other forest types, latitudes, and climate settings.

  18. Efficient inference of population size histories and locus-specific mutation rates from large-sample genomic variation data.

    Science.gov (United States)

    Bhaskar, Anand; Wang, Y X Rachel; Song, Yun S

    2015-02-01

    With the recent increase in study sample sizes in human genetics, there has been growing interest in inferring historical population demography from genomic variation data. Here, we present an efficient inference method that can scale up to very large samples, with tens or hundreds of thousands of individuals. Specifically, by utilizing analytic results on the expected frequency spectrum under the coalescent and by leveraging the technique of automatic differentiation, which allows us to compute gradients exactly, we develop a very efficient algorithm to infer piecewise-exponential models of the historical effective population size from the distribution of sample allele frequencies. Our method is orders of magnitude faster than previous demographic inference methods based on the frequency spectrum. In addition to inferring demography, our method can also accurately estimate locus-specific mutation rates. We perform extensive validation of our method on simulated data and show that it can accurately infer multiple recent epochs of rapid exponential growth, a signal that is difficult to pick up with small sample sizes. Lastly, we use our method to analyze data from recent sequencing studies, including a large-sample exome-sequencing data set of tens of thousands of individuals assayed at a few hundred genic regions. © 2015 Bhaskar et al.; Published by Cold Spring Harbor Laboratory Press.

  19. Global variations of large megathrust earthquake rupture characteristics

    Science.gov (United States)

    Kanamori, Hiroo

    2018-01-01

    Despite the surge of great earthquakes along subduction zones over the last decade and advances in observations and analysis techniques, it remains unclear whether earthquake complexity is primarily controlled by persistent fault properties or by dynamics of the failure process. We introduce the radiated energy enhancement factor (REEF), given by the ratio of an event’s directly measured radiated energy to the calculated minimum radiated energy for a source with the same seismic moment and duration, to quantify the rupture complexity. The REEF measurements for 119 large [moment magnitude (Mw) 7.0 to 9.2] megathrust earthquakes distributed globally show marked systematic regional patterns, suggesting that the rupture complexity is strongly influenced by persistent geological factors. We characterize this as the existence of smooth and rough rupture patches with varying interpatch separation, along with failure dynamics producing triggering interactions that augment the regional influences on large events. We present an improved asperity scenario incorporating both effects and categorize global subduction zones and great earthquakes based on their REEF values and slip patterns. Giant earthquakes rupturing over several hundred kilometers can occur in regions with low-REEF patches and small interpatch spacing, such as for the 1960 Chile, 1964 Alaska, and 2011 Tohoku earthquakes, or in regions with high-REEF patches and large interpatch spacing as in the case for the 2004 Sumatra and 1906 Ecuador-Colombia earthquakes. Thus, combining seismic magnitude Mw and REEF, we provide a quantitative framework to better represent the span of rupture characteristics of great earthquakes and to understand global seismicity. PMID:29750186

  20. Temporal and spatial variations of travel-time residuals in central California for Novaya Zemlya events

    International Nuclear Information System (INIS)

    Robinson, R.; Iyer, H.M.

    1976-01-01

    Eight large nuclear explosions in Novaya Zemlya from October 1969 through November 1974 were used to monitor long-term variations in crustal seismic velocity near the San Andreas fault in central California. Relative P-wave travel-time residuals appear to be accurate to approximately +-0.1 sec. Of the over 100 stations used, none show clearly significant temporal variations in residual greater than this amount, corresponding to about a 4 percent change in velocity in the upper crust. Average relative residuals at individual stations show a large spatial variation of about 1.5 sec. These variations reflect both a complex crustal geology and changes in crustal thickness and provide a potentially powerful tool for studying crustal structure

  1. Comparative analysis of face recognition techniques with illumination variation

    International Nuclear Information System (INIS)

    Jondhale, K C; Waghmare, L M

    2010-01-01

    Illumination variation is one of the major challenges in the face recognition. To deal with this problem, this paper presents comparative analysis of three different techniques. First, the DCT is employed to compensate for illumination variations in the logarithm domain. Since illumination variation lies mainly in the low frequency band, an appropriate number of DCT coefficients are truncated to reduce the variations under different lighting conditions. The nearest neighbor classifier based on Euclidean distance is employed for classification. Second, the performance of PCA is checked on normalized image. PCA is a technique used to reduce multidimensional data sets to a lower dimension for analysis. Third, LDA based methods gives a satisfactory result under controlled lighting condition. But its performance under large illumination variation is not satisfactory. So, the performance of LDA is checked on normalized image. Experimental results on the Yale B and ORL database show that the proposed approach of application of PCA and LDA on normalized dataset improves the performance significantly for the face images with large illumination variations.

  2. Isogeometric variational multiscale large-eddy simulation of fully-developed turbulent flow over a wavy wall

    KAUST Repository

    Chang, Kyungsik; Hughes, Thomas Jr R; Calo, Victor M.

    2012-01-01

    We report on the isogeometric residual-based variational multiscale (VMS) large eddy simulation of a fully developed turbulent flow over a wavy wall. To assess the predictive capability of the VMS modeling framework, we compare its predictions against the results from direct numerical simulation (DNS) and large eddy simulation (LES) and, when available, against experimental measurements. We use C 1 quadratic B-spline basis functions to represent the smooth geometry of the sinusoidal lower wall and the solution variables. The Reynolds numbers of the flows considered are 6760 and 30,000 based on the bulk velocity and average channel height. The ratio of amplitude to wavelength (α/λ) of the sinusoidal wavy surface is set to 0.05. The computational domain is 2λ×1.05λ×λ in the streamwise, wall-normal and spanwise directions, respectively. For the Re=6760 case, mean averaged quantities, including velocity and pressure profiles, and the separation/reattachment points in the recirculation region, are compared with DNS and experimental data. The turbulent kinetic energy and Reynolds stress are in good agreement with benchmark data. Coherent structures over the wavy wall are observed in isosurfaces of the Q-criterion and show similar features to those previously reported in the literature. Comparable accuracy to DNS solutions is obtained with at least one order of magnitude fewer degrees of freedom. For the Re=30,000 case, good agreement was obtained for mean wall shear stress and velocity profiles compared with available LES results reported in the literature. © 2012 Elsevier Ltd.

  3. Isogeometric variational multiscale large-eddy simulation of fully-developed turbulent flow over a wavy wall

    KAUST Repository

    Chang, Kyungsik

    2012-09-01

    We report on the isogeometric residual-based variational multiscale (VMS) large eddy simulation of a fully developed turbulent flow over a wavy wall. To assess the predictive capability of the VMS modeling framework, we compare its predictions against the results from direct numerical simulation (DNS) and large eddy simulation (LES) and, when available, against experimental measurements. We use C 1 quadratic B-spline basis functions to represent the smooth geometry of the sinusoidal lower wall and the solution variables. The Reynolds numbers of the flows considered are 6760 and 30,000 based on the bulk velocity and average channel height. The ratio of amplitude to wavelength (α/λ) of the sinusoidal wavy surface is set to 0.05. The computational domain is 2λ×1.05λ×λ in the streamwise, wall-normal and spanwise directions, respectively. For the Re=6760 case, mean averaged quantities, including velocity and pressure profiles, and the separation/reattachment points in the recirculation region, are compared with DNS and experimental data. The turbulent kinetic energy and Reynolds stress are in good agreement with benchmark data. Coherent structures over the wavy wall are observed in isosurfaces of the Q-criterion and show similar features to those previously reported in the literature. Comparable accuracy to DNS solutions is obtained with at least one order of magnitude fewer degrees of freedom. For the Re=30,000 case, good agreement was obtained for mean wall shear stress and velocity profiles compared with available LES results reported in the literature. © 2012 Elsevier Ltd.

  4. Metabolite variation in hybrid corn grain from a large-scale multisite study

    Directory of Open Access Journals (Sweden)

    Mingjie Chen

    2016-06-01

    Full Text Available Metabolite composition is strongly affected by genotype, environment, and interactions between genotype and environment, although the extent of variation caused by these factors may depend upon the type of metabolite. To characterize the complexity of genotype, environment, and their interaction in hybrid seeds, 50 genetically diverse non-genetically modified (GM maize hybrids were grown in six geographically diverse locations in North America. Polar metabolites from 553 harvested corn grain samples were isolated and analyzed by gas chromatography–mass spectrometry and 45 metabolites detected in all samples were used to generate a data matrix for statistical analysis. There was moderate variation among biological replicates and across genotypes and test sites. The genotype effects were detected by univariate and Hierarchical clustering analyses (HCA when environmental effects were excluded. Overall, environment exerted larger effects than genotype, and polar metabolite accumulation showed a geographic effect. We conclude that it is possible to increase seed polar metabolite content in hybrid corn by selection of appropriate inbred lines and growing regions.

  5. Geomagnetic field variations at the equatorial electrojet station in Sri Lanka, Peredinia

    Directory of Open Access Journals (Sweden)

    R. G. Rastogi

    2004-09-01

    Full Text Available The paper discusses the variations of the horizontal (H, vertical (Z and eastward (Y components of the geomagnetic field at Peredinia (PRD, an electrojet station in Sri Lanka, with the time of the day, season, sudden commencement (SSC and during geomagnetic storms. The daily variation of H showed a large peak around midday. The daily variation of Z appeared to be almost a time gradient curve of the daily variation of H, showing a maximum around 09:00 LT (75° EMT when the H field was increasing fastest and not at noon when Δ H was the maximum. Storm time variation of H resembled the variation of the Dst index but that of Z showed a large minimum about 2-3h before the time of minimum Dst or at the time of maximum time gradient of Dst variation. These features are compared with corresponding variations at the equatorial stations Trivandrum (TRD in India, and remarkable similarity in all observations is noticed at PRD and TRD. It is suggested that the observed abnormal features of Z variations at electrojet stations in India-Sri Lanka are due to (i direct effect of the ionospheric electrojet current (ii the induction effect of the image current by the average spatially extended conductivity region and (iii the induction current in the local subsurface conductor. It is suggested that the conductor responsible for the observed features in Z in India and Sri Lanka has to have extended spatial domain to latitudes well south of India, rather than confined to narrow Palk Strait.

  6. The U.S. Radiologist Workforce: An Analysis of Temporal and Geographic Variation by Using Large National Datasets.

    Science.gov (United States)

    Rosenkrantz, Andrew B; Hughes, Danny R; Duszak, Richard

    2016-04-01

    To determine recent trends related to temporal as well as national and statewide geographic variation in the U.S. radiologist and radiology resident workforce. This retrospective HIPAA-compliant study was exempted from the internal review board. Federal Area Health Resources Files and Medicare 5% research identifiable files were used to compute parameters related to the radiologist workforce. Geographic variation and annual temporal trends were analyzed. Pearson and Spearman correlations were assessed. Nationally, the number of radiology trainees increased 84.2% from a nadir in 1997 (3080 trainees) to 2011 (5674 trainees) and showed high state-to-state variation (range, 0-678 trainees in 2011). However, total radiologists nationally increased 39.2% from 1995 (27 906 radiologists) to 2011 (38 875 radiologists), and radiologists per 100 000 population nationally increased by 7.5% from 1995 (10.62%) to 2011 (11.42%), while showing high state-to-state variation (highest-to-lowest state ratio of 4.3). Radiologists' share of the overall physician workforce declined nationally by 8.8% from 1995 (4.0%) to 2011 (3.7%), with moderate state-to-state variation (highest-to-lowest state ratio of 1.7). Radiology trainee numbers exhibited weak-to-moderate positive state-by-state correlation with radiologists per 100 000 population (r = 0.292-0.532), but moderate-to-strong inverse correlation with the percentage of radiologists in rural practice (r = -0.464 to -0.635). Although the number of radiology trainees dramatically increased, radiologists per 100 000 population increased only slightly, and radiologists' share of the overall physician workforce declined. State-to-state variations in radiologist and radiology resident workforces are high, which suggests a potential role for geographic redistribution rather than changes in the overall workforce size.

  7. Endogenous Sheet-Averaged Tension Within a Large Epithelial Cell Colony.

    Science.gov (United States)

    Dumbali, Sandeep P; Mei, Lanju; Qian, Shizhi; Maruthamuthu, Venkat

    2017-10-01

    Epithelial cells form quasi-two-dimensional sheets that function as contractile media to effect tissue shape changes during development and homeostasis. Endogenously generated intrasheet tension is a driver of such changes, but has predominantly been measured in the presence of directional migration. The nature of epithelial cell-generated forces transmitted over supracellular distances, in the absence of directional migration, is thus largely unclear. In this report, we consider large epithelial cell colonies which are archetypical multicell collectives with extensive cell-cell contacts but with a symmetric (circular) boundary. Using the traction force imbalance method (TFIM) (traction force microscopy combined with physical force balance), we first show that one can determine the colony-level endogenous sheet forces exerted at the midline by one half of the colony on the other half with no prior assumptions on the uniformity of the mechanical properties of the cell sheet. Importantly, we find that this colony-level sheet force exhibits large variations with orientation-the difference between the maximum and minimum sheet force is comparable to the average sheet force itself. Furthermore, the sheet force at the colony midline is largely tensile but the shear component exhibits significantly more variation with orientation. We thus show that even an unperturbed epithelial colony with a symmetric boundary shows significant directional variation in the endogenous sheet tension and shear forces that subsist at the colony level.

  8. Circumpolar assessment of rhizosphere priming shows limited increase in carbon loss estimates for permafrost soils but large regional variability

    Science.gov (United States)

    Wild, B.; Keuper, F.; Kummu, M.; Beer, C.; Blume-Werry, G.; Fontaine, S.; Gavazov, K.; Gentsch, N.; Guggenberger, G.; Hugelius, G.; Jalava, M.; Koven, C.; Krab, E. J.; Kuhry, P.; Monteux, S.; Richter, A.; Shazhad, T.; Dorrepaal, E.

    2017-12-01

    Predictions of soil organic carbon (SOC) losses in the northern circumpolar permafrost area converge around 15% (± 3% standard error) of the initial C pool by 2100 under the RCP 8.5 warming scenario. Yet, none of these estimates consider plant-soil interactions such as the rhizosphere priming effect (RPE). While laboratory experiments have shown that the input of plant-derived compounds can stimulate SOC losses by up to 1200%, the magnitude of RPE in natural ecosystems is unknown and no methods for upscaling exist so far. We here present the first spatial and depth explicit RPE model that allows estimates of RPE on a large scale (PrimeSCale). We combine available spatial data (SOC, C/N, GPP, ALT and ecosystem type) and new ecological insights to assess the importance of the RPE at the circumpolar scale. We use a positive saturating relationship between the RPE and belowground C allocation and two ALT-dependent rooting-depth distribution functions (for tundra and boreal forest) to proportionally assign belowground C allocation and RPE to individual soil depth increments. The model permits to take into account reasonable limiting factors on additional SOC losses by RPE including interactions between spatial and/or depth variation in GPP, plant root density, SOC stocks and ALT. We estimate potential RPE-induced SOC losses at 9.7 Pg C (5 - 95% CI: 1.5 - 23.2 Pg C) by 2100 (RCP 8.5). This corresponds to an increase of the current permafrost SOC-loss estimate from 15% of the initial C pool to about 16%. If we apply an additional molar C/N threshold of 20 to account for microbial C limitation as a requirement for the RPE, SOC losses by RPE are further reduced to 6.5 Pg C (5 - 95% CI: 1.0 - 16.8 Pg C) by 2100 (RCP 8.5). Although our results show that current estimates of permafrost soil C losses are robust without taking into account the RPE, our model also highlights high-RPE risk in Siberian lowland areas and Alaska north of the Brooks Range. The small overall impact of

  9. [Correlation of intraocular pressure variation after visual field examination with 24-hour intraocular pressure variations in primary open-angle glaucoma].

    Science.gov (United States)

    Noro, Takahiko; Nakamoto, Kenji; Sato, Makoto; Yasuda, Noriko; Ito, Yoshinori; Ogawa, Shumpei; Nakano, Tadashi; Tsuneoka, Hiroshi

    2014-10-01

    We retrospectively examined intraocular pressure variations after visual field examination in primary open angle glaucoma (POAG), together with its influencing factors and its association with 24-hour intraocular pressure variations. Subjects were 94 eyes (52 POAG patients) subjected to measurements of 24-hour intraocular pressure and of changes in intraocular pressure after visual field examination using a Humphrey Visual Field Analyzer. Subjects were classified into three groups according to the magnitude of variation (large, intermediate and small), and 24-hour intraocular pressure variations were compared among the three groups. Factors influencing intraocular pressure variations after visual field examination and those associated with the large variation group were investigated. Average intraocular pressure variation after visual field examination was -0.28 ± 1.90 (range - 6.0(-) + 5.0) mmHg. No significant influencing factors were identified. The intraocular pressure at 3 a.m. was significantly higher in the large variation group than other two groups (p field examination. Increases in intraocular pressure during the night might be associated with large intraocular pressure variations after visual field examination.

  10. Monte Carlo estimation of total variation distance of Markov chains on large spaces, with application to phylogenetics.

    Science.gov (United States)

    Herbei, Radu; Kubatko, Laura

    2013-03-26

    Markov chains are widely used for modeling in many areas of molecular biology and genetics. As the complexity of such models advances, it becomes increasingly important to assess the rate at which a Markov chain converges to its stationary distribution in order to carry out accurate inference. A common measure of convergence to the stationary distribution is the total variation distance, but this measure can be difficult to compute when the state space of the chain is large. We propose a Monte Carlo method to estimate the total variation distance that can be applied in this situation, and we demonstrate how the method can be efficiently implemented by taking advantage of GPU computing techniques. We apply the method to two Markov chains on the space of phylogenetic trees, and discuss the implications of our findings for the development of algorithms for phylogenetic inference.

  11. Structured approaches to large-scale systems: Variational integrators for interconnected Lagrange-Dirac systems and structured model reduction on Lie groups

    Science.gov (United States)

    Parks, Helen Frances

    This dissertation presents two projects related to the structured integration of large-scale mechanical systems. Structured integration uses the considerable differential geometric structure inherent in mechanical motion to inform the design of numerical integration schemes. This process improves the qualitative properties of simulations and becomes especially valuable as a measure of accuracy over long time simulations in which traditional Gronwall accuracy estimates lose their meaning. Often, structured integration schemes replicate continuous symmetries and their associated conservation laws at the discrete level. Such is the case for variational integrators, which discretely replicate the process of deriving equations of motion from variational principles. This results in the conservation of momenta associated to symmetries in the discrete system and conservation of a symplectic form when applicable. In the case of Lagrange-Dirac systems, variational integrators preserve a discrete analogue of the Dirac structure preserved in the continuous flow. In the first project of this thesis, we extend Dirac variational integrators to accommodate interconnected systems. We hope this work will find use in the fields of control, where a controlled system can be thought of as a "plant" system joined to its controller, and in the approach of very large systems, where modular modeling may prove easier than monolithically modeling the entire system. The second project of the thesis considers a different approach to large systems. Given a detailed model of the full system, can we reduce it to a more computationally efficient model without losing essential geometric structures in the system? Asked without the reference to structure, this is the essential question of the field of model reduction. The answer there has been a resounding yes, with Principal Orthogonal Decomposition (POD) with snapshots rising as one of the most successful methods. Our project builds on previous work

  12. Large Variations in HIV-1 Viral Load Explained by Shifting-Mosaic Metapopulation Dynamics

    Science.gov (United States)

    Lythgoe, Katrina A.; Blanquart, François

    2016-01-01

    The viral population of HIV-1, like many pathogens that cause systemic infection, is structured and differentiated within the body. The dynamics of cellular immune trafficking through the blood and within compartments of the body has also received wide attention. Despite these advances, mathematical models, which are widely used to interpret and predict viral and immune dynamics in infection, typically treat the infected host as a well-mixed homogeneous environment. Here, we present mathematical, analytical, and computational results that demonstrate that consideration of the spatial structure of the viral population within the host radically alters predictions of previous models. We study the dynamics of virus replication and cytotoxic T lymphocytes (CTLs) within a metapopulation of spatially segregated patches, representing T cell areas connected by circulating blood and lymph. The dynamics of the system depend critically on the interaction between CTLs and infected cells at the within-patch level. We show that for a wide range of parameters, the system admits an unexpected outcome called the shifting-mosaic steady state. In this state, the whole body’s viral population is stable over time, but the equilibrium results from an underlying, highly dynamic process of local infection and clearance within T-cell centers. Notably, and in contrast to previous models, this new model can explain the large differences in set-point viral load (SPVL) observed between patients and their distribution, as well as the relatively low proportion of cells infected at any one time, and alters the predicted determinants of viral load variation. PMID:27706164

  13. Slags in a Large Variation Range of Oxygen Potential Based on the Ion and Molecule Coexistence Theory

    Science.gov (United States)

    Yang, Xue-Min; Li, Jin-Yan; Zhang, Meng; Chai, Guo-Min; Zhang, Jian

    2014-12-01

    A thermodynamic model for predicting sulfide capacity of CaO-FeO-Fe2O3-Al2O3-P2O5 slags in a large variation range of oxygen potential corresponding to mass percentage of FetO from 1.88 to 55.50 pct, i.e., IMCT- model, has been developed by coupling with the deduced desulfurization mechanism of the slags based on the ion and molecule coexistence theory (IMCT). The developed IMCT- model has been verified through comparing the determined sulfide capacity after Ban-ya et al.[20] with the calculated by the developed IMCT- model and the calculated by the reported sulfide capacity models such as the KTH model. Mass percentage of FetO as 6.75 pct corresponding to the mass action concentration of FetO as 0.0637 or oxygen partial as 2.27 × 10-6 Pa is the criterion for distinguishing reducing and oxidizing zones for the slags. Sulfide capacity of the slags in reducing zone is controlled by reaction ability of CaO regardless of slag oxidization ability. However, sulfide capacity of the slags in oxidizing zone shows an obvious increase tendency with the increasing of slag oxidization ability. Sulfide capacity of the slags in reducing zone keeps almost constant with variation of the simplified complex basicity (pct CaO)/((pct Al2O3) + (pct P2O5)), or optical basicity, or the mass action concentration ratios of N FeO/ N CaO, , , and . Sulfide capacity of the slags in oxidizing zone shows an obvious increase with the increasing of the simplified complex basicity (pct CaO)/((pct Al2O3) + (pct P2O5)) or optical basicity, or the aforementioned mass action concentration ratios. Thus, the aforementioned mass action concentration ratios and the corresponding mass percentage ratios of various iron oxides to basic oxide CaO are recommended to represent the comprehensive effect of various iron oxides and basic oxide CaO on sulfide capacity of the slags.

  14. Quasi-periodic variations of cometary ion fluxes at large distances from comet Halley

    Energy Technology Data Exchange (ETDEWEB)

    Richter, A.K.; Daly, P.W.; Verigin, M.I.; Gringauz, K.I.; Erdos, G.; Kecskemety, K.; Somogyi, A.J.; Szego, K.; Varga, A.; McKenna-Lawlor, S.

    1989-04-01

    Large variations, with a period of about 4 h, in the energetic ion fluxes have been observed far upstream (between 2 and 10 million kilometers) of comet Halley on both the Vega-1 and Giotto spacecraft. We have fitted the cometocentric distances of the occurrences to a simple model of expanding shells of neutral particles, the production of which is modulated by the spin of the comet nucleus, and have achieved excellent agreement between the two spacecraft. We derive an expansion speed for the neutrals of 6.18 +- 0.14 km s/sup -1/. Possible candidates for the neutrals are hydrogen atoms, created by the photo-dissociation of OH with a speed of 8 km s/sup -1/, or oxygen atoms, produced from the photo-dissociation of CO/sub 2/ with a speed of 6.5 km s/sup -1/.

  15. Neighborhood diversity of large trees shows independent species patterns in a mixed dipterocarp forest in Sri Lanka.

    Science.gov (United States)

    Punchi-Manage, Ruwan; Wiegand, Thorsten; Wiegand, Kerstin; Getzin, Stephan; Huth, Andreas; Gunatilleke, C V Savitri; Gunatilleke, I A U Nimal

    2015-07-01

    Interactions among neighboring individuals influence plant performance and should create spatial patterns in local community structure. In order to assess the role of large trees in generating spatial patterns in local species richness, we used the individual species-area relationship (ISAR) to evaluate the species richness of trees of different size classes (and dead trees) in circular neighborhoods with varying radius around large trees of different focal species. To reveal signals of species interactions, we compared the ISAR function of the individuals of focal species with that of randomly selected nearby locations. We expected that large trees should strongly affect the community structure of smaller trees in their neighborhood, but that these effects should fade away with increasing size class. Unexpectedly, we found that only few focal species showed signals of species interactions with trees of the different size classes and that this was less likely for less abundant focal species. However, the few and relatively weak departures from independence were consistent with expectations of the effect of competition for space and the dispersal syndrome on spatial patterns. A noisy signal of competition for space found for large trees built up gradually with increasing life stage; it was not yet present for large saplings but detectable for intermediates. Additionally, focal species with animal-dispersed seeds showed higher species richness in their neighborhood than those with gravity- and gyration-dispersed seeds. Our analysis across the entire ontogeny from recruits to large trees supports the hypothesis that stochastic effects dilute deterministic species interactions in highly diverse communities. Stochastic dilution is a consequence of the stochastic geometry of biodiversity in species-rich communities where the identities of the nearest neighbors of a given plant are largely unpredictable. While the outcome of local species interactions is governed for each

  16. Dopa decarboxylase (Ddc) affects variation in Drosophila longevity.

    Science.gov (United States)

    De Luca, Maria; Roshina, Nataliya V; Geiger-Thornsberry, Gretchen L; Lyman, Richard F; Pasyukova, Elena G; Mackay, Trudy F C

    2003-08-01

    Mutational analyses in model organisms have shown that genes affecting metabolism and stress resistance regulate life span, but the genes responsible for variation in longevity in natural populations are largely unidentified. Previously, we mapped quantitative trait loci (QTLs) affecting variation in longevity between two Drosophila melanogaster strains. Here, we show that the longevity QTL in the 36E;38B cytogenetic interval on chromosome 2 contains multiple closely linked QTLs, including the Dopa decarboxylase (Ddc) locus. Complementation tests to mutations show that Ddc is a positional candidate gene for life span in these strains. Linkage disequilibrium (LD) mapping in a sample of 173 alleles from a single population shows that three common molecular polymorphisms in Ddc account for 15.5% of the genetic contribution to variance in life span from chromosome 2. The polymorphisms are in strong LD, and the effects of the haplotypes on longevity suggest that the polymorphisms are maintained by balancing selection. DDC catalyzes the final step in the synthesis of the neurotransmitters, dopamine and serotonin. Thus, these data implicate variation in the synthesis of bioamines as a factor contributing to natural variation in individual life span.

  17. An extended algebraic variational multiscale-multigrid-multifractal method (XAVM4) for large-eddy simulation of turbulent two-phase flow

    Science.gov (United States)

    Rasthofer, U.; Wall, W. A.; Gravemeier, V.

    2018-04-01

    A novel and comprehensive computational method, referred to as the eXtended Algebraic Variational Multiscale-Multigrid-Multifractal Method (XAVM4), is proposed for large-eddy simulation of the particularly challenging problem of turbulent two-phase flow. The XAVM4 involves multifractal subgrid-scale modeling as well as a Nitsche-type extended finite element method as an approach for two-phase flow. The application of an advanced structural subgrid-scale modeling approach in conjunction with a sharp representation of the discontinuities at the interface between two bulk fluids promise high-fidelity large-eddy simulation of turbulent two-phase flow. The high potential of the XAVM4 is demonstrated for large-eddy simulation of turbulent two-phase bubbly channel flow, that is, turbulent channel flow carrying a single large bubble of the size of the channel half-width in this particular application.

  18. Exploring language variation across Europe

    DEFF Research Database (Denmark)

    Hovy, Dirk; Johannsen, Anders Trærup

    2016-01-01

    Language varies not only between countries, but also along regional and sociodemographic lines. This variation is one of the driving factors behind language change. However, investigating language variation is a complex undertaking: the more factors we want to consider, the more data we need. Tra...... use of large amounts of data and provides statistical analyses, maps, and interactive features that enable scholars to explore language variation in a data-driven way.......Language varies not only between countries, but also along regional and sociodemographic lines. This variation is one of the driving factors behind language change. However, investigating language variation is a complex undertaking: the more factors we want to consider, the more data we need...... training in both variational linguistics and computational methods, a combination that is still not common. We take a first step here to alleviate the problem by providing an interface to explore large-scale language variation along several socio-demographic factors without programming knowledge. It makes...

  19. Macrophytes shape trophic niche variation among generalist fishes.

    Directory of Open Access Journals (Sweden)

    Ivana Vejříková

    Full Text Available Generalist species commonly have a fundamental role in ecosystems as they can integrate spatially distinct habitats and food-web compartments, as well as control the composition, abundance and behavior of organisms at different trophic levels. Generalist populations typically consist of specialized individuals, but the potential for and hence degree of individual niche variation can be largely determined by habitat complexity. We compared individual niche variation within three generalist fishes between two comparable lakes in the Czech Republic differing in macrophyte cover, i.e. macrophyte-rich Milada and macrophyte-poor Most. We tested the hypothesis that large individual niche variation among generalist fishes is facilitated by the presence of macrophytes, which provides niches and predation shelter for fish and their prey items. Based on results from stable nitrogen (δ15N and carbon (δ13C isotopic mixing models, perch (Perca fluviatilis L. and rudd (Scardinius erythrophthalmus (L. showed larger individual variation (i.e., variance in trophic position in Milada as compared to Most, whereas no significant between-lake differences were observed for roach (Rutilus rutilus (L.. Contrary to our hypothesis, all the three species showed significantly lower individual variation in the relative reliance on littoral food resources in Milada than in Most. Rudd relied significantly more whereas perch and roach relied less on littoral food resources in Milada than in Most, likely due to prevalent herbivory by rudd and prevalent zooplanktivory by perch and roach in the macrophyte-rich Milada as compared to macrophyte-poor Most. Our study demonstrates how the succession of macrophyte vegetation, via its effects on the physical and biological complexity of the littoral zone and on the availability of small prey fish and zooplankton, can strongly influence individual niche variation among generalist fishes with different ontogenetic trajectories, and hence

  20. Macrophytes shape trophic niche variation among generalist fishes

    Science.gov (United States)

    Vejřík, Lukáš; Šmejkal, Marek; Čech, Martin; Sajdlová, Zuzana; Frouzová, Jaroslava; Kiljunen, Mikko; Peterka, Jiří

    2017-01-01

    Generalist species commonly have a fundamental role in ecosystems as they can integrate spatially distinct habitats and food-web compartments, as well as control the composition, abundance and behavior of organisms at different trophic levels. Generalist populations typically consist of specialized individuals, but the potential for and hence degree of individual niche variation can be largely determined by habitat complexity. We compared individual niche variation within three generalist fishes between two comparable lakes in the Czech Republic differing in macrophyte cover, i.e. macrophyte-rich Milada and macrophyte-poor Most. We tested the hypothesis that large individual niche variation among generalist fishes is facilitated by the presence of macrophytes, which provides niches and predation shelter for fish and their prey items. Based on results from stable nitrogen (δ15N) and carbon (δ13C) isotopic mixing models, perch (Perca fluviatilis L.) and rudd (Scardinius erythrophthalmus (L.)) showed larger individual variation (i.e., variance) in trophic position in Milada as compared to Most, whereas no significant between-lake differences were observed for roach (Rutilus rutilus (L.)). Contrary to our hypothesis, all the three species showed significantly lower individual variation in the relative reliance on littoral food resources in Milada than in Most. Rudd relied significantly more whereas perch and roach relied less on littoral food resources in Milada than in Most, likely due to prevalent herbivory by rudd and prevalent zooplanktivory by perch and roach in the macrophyte-rich Milada as compared to macrophyte-poor Most. Our study demonstrates how the succession of macrophyte vegetation, via its effects on the physical and biological complexity of the littoral zone and on the availability of small prey fish and zooplankton, can strongly influence individual niche variation among generalist fishes with different ontogenetic trajectories, and hence the overall

  1. Variational estimates of point-kinetics parameters

    International Nuclear Information System (INIS)

    Favorite, J.A.; Stacey, W.M. Jr.

    1995-01-01

    Variational estimates of the effect of flux shifts on the integral reactivity parameter of the point-kinetics equations and on regional power fractions were calculated for a variety of localized perturbations in two light water reactor (LWR) model problems representing a small, tightly coupled core and a large, loosely coupled core. For the small core, the flux shifts resulting from even relatively large localized reactivity changes (∼600 pcm) were small, and the standard point-kinetics approximation estimates of reactivity were in error by only ∼10% or less, while the variational estimates were accurate to within ∼1%. For the larger core, significant (>50%) flux shifts occurred in response to local perturbations, leading to errors of the same magnitude in the standard point-kinetics approximation of the reactivity worth. For positive reactivity, the error in the variational estimate of reactivity was only a few percent in the larger core, and the resulting transient power prediction was 1 to 2 orders of magnitude more accurate than with the standard point-kinetics approximation. For a large, local negative reactivity insertion resulting in a large flux shift, the accuracy of the variational estimate broke down. The variational estimate of the effect of flux shifts on reactivity in point-kinetics calculations of transients in LWR cores was found to generally result in greatly improved accuracy, relative to the standard point-kinetics approximation, the exception being for large negative reactivity insertions with large flux shifts in large, loosely coupled cores

  2. Developing natural convection in a fluid layer with localized heating and large viscosity variation

    Energy Technology Data Exchange (ETDEWEB)

    Hickox, C.E.; Chu, Tze Yao.

    1991-01-01

    Numerical simulations and laboratory experiments are used to elucidate aspects of transient natural convection in a magma chamber. The magma chamber is modeled as a horizontal fluid layer confined within an enclosure of square planform and heated from below by a strip heater centered on the lower boundary of the enclosure. The width of the strip heater and the depth of the fluid layer are one-fourth of the layer width. Corn syrup is used as the working fluid in order to approximate the large viscosity variation with temperature and the large Prandtl number typical of magma. The quiescent, uniform, fluid layer is subjected to instantaneous heating from the strip heater producing a transient flow which is dominated by two counter-rotating convective cells. Experimentally determined characteristics of the developing flow are compared with numerical simulations carried out with a finite element computer program. The results of numerical simulations are in essential agreement with experimental data. Differences between the numerical simulations and experimental measurements are conjectured to result from non-ideal effects present in the experiment which are difficult to represent accurately in a numerical simulation.

  3. The impact of accelerating faster than exponential population growth on genetic variation.

    Science.gov (United States)

    Reppell, Mark; Boehnke, Michael; Zöllner, Sebastian

    2014-03-01

    Current human sequencing projects observe an abundance of extremely rare genetic variation, suggesting recent acceleration of population growth. To better understand the impact of such accelerating growth on the quantity and nature of genetic variation, we present a new class of models capable of incorporating faster than exponential growth in a coalescent framework. Our work shows that such accelerated growth affects only the population size in the recent past and thus large samples are required to detect the models' effects on patterns of variation. When we compare models with fixed initial growth rate, models with accelerating growth achieve very large current population sizes and large samples from these populations contain more variation than samples from populations with constant growth. This increase is driven almost entirely by an increase in singleton variation. Moreover, linkage disequilibrium decays faster in populations with accelerating growth. When we instead condition on current population size, models with accelerating growth result in less overall variation and slower linkage disequilibrium decay compared to models with exponential growth. We also find that pairwise linkage disequilibrium of very rare variants contains information about growth rates in the recent past. Finally, we demonstrate that models of accelerating growth may substantially change estimates of present-day effective population sizes and growth times.

  4. The capture of heritable variation for genetic quality through social competition.

    Science.gov (United States)

    Wolf, Jason B; Harris, W Edwin; Royle, Nick J

    2008-09-01

    In theory, females of many species choose mates based on traits that are indicators of male genetic quality. A fundamental question in evolutionary biology is why genetic variation for such indicator traits persists despite strong persistent selection imposed by female preference, which is known as the lek paradox. One potential solution to the lek paradox suggests that the traits that are targets of mate choice should evolve condition-dependent expression and that condition should have a large genetic variance. Condition is expected to exhibit high genetic variance because it is affected by a large number of physiological processes and hence, condition-dependent traits should 'capture' variation contributed by a large number of loci. We suggest that a potentially important cause of variation in condition is competition for limited resources. Here, we discuss a pair of models to analyze the evolutionary genetics of traits affected by success in social competition for resources. We show that competition can contribute to genetic variation of 'competition-dependent' traits that have fundamentally different evolutionary properties than other sources of variation. Competition dependence can make traits honest indicators of genetic quality by revealing the relative competitive ability of males, can provide a component of heritable variation that does not contribute to trait evolution, and can help maintain heritable variation under directional selection. Here we provide a general introduction to the concept of competition dependence and briefly introduce two models to demonstrate the potential evolutionary consequences of competition-dependent trait expression.

  5. Automated quantification of pulmonary emphysema from computed tomography scans: comparison of variation and correlation of common measures in a large cohort

    Science.gov (United States)

    Keller, Brad M.; Reeves, Anthony P.; Yankelevitz, David F.; Henschke, Claudia I.

    2010-03-01

    The purpose of this work was to retrospectively investigate the variation of standard indices of pulmonary emphysema from helical computed tomographic (CT) scans as related to inspiration differences over a 1 year interval and determine the strength of the relationship between these measures in a large cohort. 626 patients that had 2 scans taken at an interval of 9 months to 15 months (μ: 381 days, σ: 31 days) were selected for this work. All scans were acquired at a 1.25mm slice thickness using a low dose protocol. For each scan, the emphysema index (EI), fractal dimension (FD), mean lung density (MLD), and 15th percentile of the histogram (HIST) were computed. The absolute and relative changes for each measure were computed and the empirical 95% confidence interval was reported both in non-normalized and normalized scales. Spearman correlation coefficients are computed between the relative change in each measure and relative change in inspiration between each scan-pair, as well as between each pair-wise combination of the four measures. EI varied on a range of -10.5 to 10.5 on a non-normalized scale and -15 to 15 on a normalized scale, with FD and MLD showing slightly larger but comparable spreads, and HIST having a much larger variation. MLD was found to show the strongest correlation to inspiration change (r=0.85, pemphysema index and fractal dimension have the least variability overall of the commonly used measures of emphysema and that they offer the most unique quantification of emphysema relative to each other.

  6. Large variation in the Rubisco kinetics of diatoms reveals diversity among their carbon-concentrating mechanisms

    Science.gov (United States)

    Young, Jodi N.; Heureux, Ana M.C.; Sharwood, Robert E.; Rickaby, Rosalind E.M.; Morel, François M.M.; Whitney, Spencer M.

    2016-01-01

    While marine phytoplankton rival plants in their contribution to global primary productivity, our understanding of their photosynthesis remains rudimentary. In particular, the kinetic diversity of the CO2-fixing enzyme, Rubisco, in phytoplankton remains unknown. Here we quantify the maximum rates of carboxylation (k cat c), oxygenation (k cat o), Michaelis constants (K m) for CO2 (K C) and O2 (K O), and specificity for CO2 over O2 (SC/O) for Form I Rubisco from 11 diatom species. Diatom Rubisco shows greater variation in K C (23–68 µM), SC/O (57–116mol mol−1), and K O (413–2032 µM) relative to plant and algal Rubisco. The broad range of K C values mostly exceed those of C4 plant Rubisco, suggesting that the strength of the carbon-concentrating mechanism (CCM) in diatoms is more diverse, and more effective than previously predicted. The measured k cat c for each diatom Rubisco showed less variation (2.1–3.7s−1), thus averting the canonical trade-off typically observed between K C and k cat c for plant Form I Rubisco. Uniquely, a negative relationship between K C and cellular Rubisco content was found, suggesting variation among diatom species in how they allocate their limited cellular resources between Rubisco synthesis and their CCM. The activation status of Rubisco in each diatom was low, indicating a requirement for Rubisco activase. This work highlights the need to better understand the correlative natural diversity between the Rubisco kinetics and CCM of diatoms and the underpinning mechanistic differences in catalytic chemistry among the Form I Rubisco superfamily. PMID:27129950

  7. Large individual differences in free recall

    OpenAIRE

    Tarnow, Eugen

    2016-01-01

    Using single factor ANOVA I show that there are large individual differences in free recall ({\\eta} ranges from 0.09-0.26) including the total recall, the balance between recency and primacy, and the initial recall (subsequent recalls show smaller individual differences). All three memory properties are relatively uncorrelated. The variance in the initial position may be a measure of executive control and is correlated with total recall (the smaller the variation, the larger the recall).

  8. Individual Variation in the Late Positive Complex to Semantic Anomalies

    Science.gov (United States)

    Kos, Miriam; van den Brink, Danielle; Hagoort, Peter

    2012-01-01

    It is well-known that, within ERP paradigms of sentence processing, semantically anomalous words elicit N400 effects. Less clear, however, is what happens after the N400. In some cases N400 effects are followed by Late Positive Complexes (LPC), whereas in other cases such effects are lacking. We investigated several factors which could affect the LPC, such as contextual constraint, inter-individual variation, and working memory. Seventy-two participants read sentences containing a semantic manipulation (Whipped cream tastes sweet/anxious and creamy). Neither contextual constraint nor working memory correlated with the LPC. Inter-individual variation played a substantial role in the elicitation of the LPC with about half of the participants showing a negative response and the other half showing an LPC. This individual variation correlated with a syntactic ERP as well as an alternative semantic manipulation. In conclusion, our results show that inter-individual variation plays a large role in the elicitation of the LPC and this may account for the diversity in LPC findings in language research. PMID:22973249

  9. 19 CFR 113.75 - Bond conditions for deferral of duty on large yachts imported for sale at United States boat shows.

    Science.gov (United States)

    2010-04-01

    ... yachts imported for sale at United States boat shows. 113.75 Section 113.75 Customs Duties U.S. CUSTOMS... Customs Bond Conditions § 113.75 Bond conditions for deferral of duty on large yachts imported for sale at....C. 1484b for a dutiable large yacht imported for sale at a United States boat show must conform to...

  10. Large-eddy simulations for turbulent flows

    International Nuclear Information System (INIS)

    Husson, S.

    2007-07-01

    The aim of this work is to study the impact of thermal gradients on a turbulent channel flow with imposed wall temperatures and friction Reynolds numbers of 180 and 395. In this configuration, temperature variations can be strong and induce significant variations of the fluid properties. We consider the low Mach number equations and carry out large eddy simulations. We first validate our simulations thanks to comparisons of some of our LES results with DNS data. Then, we investigate the influence of the variations of the conductivity and the viscosity and show that we can assume these properties constant only for weak temperature gradients. We also study the thermal sub-grid-scale modelling and find no difference when the sub-grid-scale Prandtl number is taken constant or dynamically calculated. The analysis of the effects of strongly increasing the temperature ratio mainly shows a dissymmetry of the profiles. The physical mechanism responsible of these modifications is explained. Finally, we use semi-local scaling and the Van Driest transformation and we show that they lead to a better correspondence of the low and high temperature ratios profiles. (author)

  11. Wandel und Variation in der Morphosyntax der schweizerdeutschen Dialekte

    Directory of Open Access Journals (Sweden)

    Elvira Glaser

    2014-12-01

    Full Text Available Syntactic Variation and change in Swiss German dialects The article deals with the areal distribution of morphosyntactic variants in Swiss German dialects. The Zurich project “Syntaktischer Atlas der deutschen Schweiz” (SADS has provided a lot of evidence for the existence of syntactic isoglosses within the German-speaking regions of Switzerland. In the following, we will discuss several types of variant distribution. There are syntactic variables showing a division of Western and Eastern Swiss German dialects, a division well known from phonology and lexis. In addition, we find few archaic variants restricted to southern Highest Alemannic, again in line with other linguistic levels. Most interesting are some variants showing up in quite small – and differing – regions. These regions usually do not only show these specific variants but variation with a more common variant. This leads to a discussion of the implications of variation. Variation is not only seen as an indication of an ongoing change, but it is argued that there is evidence for a long lasting variational situation and largely stable variation respectively. Several possible types of comparison with older data and between age groups (apparent time analysis within the data are presented. There are relatively few cases where we can show larger shifts between two regional variants and there seem to be only some rare cases of syntactic influence by Standard German introducing new variants. With respect to the old question of morphosyntactic borrowing, Swiss German dialects show cases of resistance as well as cases of interference, the latter concerning loan translation and semantic adaptation if the structure favors it.

  12. Spatial and temporal small-scale variation in groundwater quality of a shallow sandy aquifer

    DEFF Research Database (Denmark)

    Bjerg, Poul Løgstrup; Christensen, Thomas Højlund

    1992-01-01

    The groundwater quality of a shallow unconfined sandy aquifer has been characterized for pH, alkalinity, chloride, nitrate, sulfate, calcium, magnesium, sodium and potassium in terms of vertical and horizontal variations (350 groundwater samples). The test area is located within a farmland lot....... The geology of the area described on the basis of 31 sediment cores appears relatively homogeneous. Large vertical and horizontal variations were observed. The vertical variations are strongly affected by the deviating composition of the agricultural infiltration water. The horizontal variations show very...

  13. Intra and Interspecific Variations of Gene Expression Levels in Yeast Are Largely Neutral: (Nei Lecture, SMBE 2016, Gold Coast).

    Science.gov (United States)

    Yang, Jian-Rong; Maclean, Calum J; Park, Chungoo; Zhao, Huabin; Zhang, Jianzhi

    2017-09-01

    It is commonly, although not universally, accepted that most intra and interspecific genome sequence variations are more or less neutral, whereas a large fraction of organism-level phenotypic variations are adaptive. Gene expression levels are molecular phenotypes that bridge the gap between genotypes and corresponding organism-level phenotypes. Yet, it is unknown whether natural variations in gene expression levels are mostly neutral or adaptive. Here we address this fundamental question by genome-wide profiling and comparison of gene expression levels in nine yeast strains belonging to three closely related Saccharomyces species and originating from five different ecological environments. We find that the transcriptome-based clustering of the nine strains approximates the genome sequence-based phylogeny irrespective of their ecological environments. Remarkably, only ∼0.5% of genes exhibit similar expression levels among strains from a common ecological environment, no greater than that among strains with comparable phylogenetic relationships but different environments. These and other observations strongly suggest that most intra and interspecific variations in yeast gene expression levels result from the accumulation of random mutations rather than environmental adaptations. This finding has profound implications for understanding the driving force of gene expression evolution, genetic basis of phenotypic adaptation, and general role of stochasticity in evolution. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  14. Insights into Intraspecies Variation in Primate Prosocial Behavior: Capuchins (Cebus apella Fail to Show Prosociality on a Touchscreen Task

    Directory of Open Access Journals (Sweden)

    Lindsey A. Drayton

    2014-04-01

    Full Text Available Over the past decade, many researchers have used food donation tasks to test whether nonhuman primates show human-like patterns of prosocial behavior in experimental settings. Although these tasks are elegant in their simplicity, performance within and across species is difficult to explain under a unified theoretical framework. Here, we attempt to better understand variation in prosociality by examining the circumstances that promote and hinder the expression of prosocial preferences. To this end, we tested whether capuchin monkeys (Cebus apella—a species that has previously demonstrated prosocial preferences—would behave prosocially using a novel touchscreen task. In contrast to previous studies, we found that capuchins as a group did not prosocially deliver food to a partner. Importantly however, data from control conditions revealed that subjects demonstrated limited understanding of the reward contingencies of the task. We also compared individuals’ performance in the current study with their performance in a previously published prosociality study. We conclude by discussing how continuing to explore intraspecies variation in performance on prosocial tasks may help inform debates regarding the existence of other-regarding preferences in nonhuman species.

  15. 19 CFR Appendix C to Part 113 - Bond for Deferral of Duty on Large Yachts Imported for Sale at United States Boat Shows

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Bond for Deferral of Duty on Large Yachts Imported... Appendix C to Part 113—Bond for Deferral of Duty on Large Yachts Imported for Sale at United States Boat Shows Bond for Deferral of Duty on Large Yachts Imported for Sale at United States Boat Shows ____, as...

  16. Computing the Taxonomic, Morphological and Sexual Variations of Bornean Hornbills (family: Bucerotidae)

    Science.gov (United States)

    Laman, Charlie J. M.; Kho, Angel

    Bornean Hornbills (Family Bucerotidae) are omnivorous creatures, distinguished for their large size and large bill. In our study, only five out of eight species of Bornean hornbills were available. Our aims were to determine the taxonomic, morphological and sexual variations, among the species. Nine morphological features were measured from 83 specimens. Canonical Discriminant and Cluster analyses showed that the data were successfully clustered into 5 species. Logistic regression analyses showed that the diagnostic character differentiation is total length. Further results showed that males tend to be bigger than females.

  17. Decadal variations in groundwater quality

    DEFF Research Database (Denmark)

    Jessen, Søren; Postma, Dieke; Thorling, Lærke

    2017-01-01

    Twenty-five years of groundwater quality monitoring in a sandy aquifer beneath agricultural fields showed large temporal and spatial variations in major ion groundwater chemistry, which were linked closely to the nitrate (NO3) content of agricultural recharge. Between 1988 and 2013, the NO3 content...... of water in the oxidized zone of the aquifer nearly halved, following implementation of action plans to reduce N leaching from agriculture. However, due to denitrification by pyrite oxidation in the aquifer, a plume of sulfate-rich water migrates through the aquifer as a legacy of the historical NO3...... loading. Agriculture thus is an important determinant of major ion groundwater chemistry. Temporal and spatial variations in the groundwater quality were simulated using a 2D reactive transport model, which combined effects of the historical NO3 leaching and denitrification, with dispersive mixing...

  18. Variation in free jumping technique within and among horses with little experience in show jumping

    NARCIS (Netherlands)

    Santamaria, S.; Bobbert, M.F.; Back, W.; Barneveld, A.; van Weeren, P.R.

    2004-01-01

    Objective - To quantify variation in the jumping technique within and among young horses with little jumping experience, establish relationships between kinetic and kinematic variables, and identify a limited set of variables characteristic for detecting differences in jumping performance among

  19. Variation in immune parameters and disease prevalence among Lesser Black-backed Gulls (Larus fuscus sp. with different migratory strategies.

    Directory of Open Access Journals (Sweden)

    Elena Arriero

    Full Text Available The ability to control infections is a key trait for migrants that must be balanced against other costly features of the migratory life. In this study we explored the links between migration and disease ecology by examining natural variation in parasite exposure and immunity in several populations of Lesser Black-backed Gulls (Larus fuscus with different migratory strategies. We found higher activity of natural antibodies in long distance migrants from the nominate subspecies L.f.fuscus. Circulating levels of IgY showed large variation at the population level, while immune parameters associated with antimicrobial activity showed extensive variation at the individual level irrespective of population or migratory strategy. Pathogen prevalence showed large geographical variation. However, the seroprevalence of one of the gull-specific subtypes of avian influenza (H16 was associated to the migratory strategy, with lower prevalence among the long-distance migrants, suggesting that migration may play a role in disease dynamics of certain pathogens at the population level.

  20. Isolation and identification of 4-a-rhamnosyloxy benzyl glucosinolate in Noccaea caerulescens showing intraspecific variation

    NARCIS (Netherlands)

    Graaf, de R.M.; Krosse, S.; Swolfs, A.E.M.; Brinke, te E.; Prill, N.; Leimu, R.; Galen, van P.M.; Wang, Y.; Aarts, M.G.M.; Dam, van N.M.

    2015-01-01

    Glucosinolates are secondary plant compounds typically found in members of the Brassicaceae and a few other plant families. Usually each plant species contains a specific subset of the ~130 different glucosinolates identified to date. However, intraspecific variation in glucosinolate profiles is

  1. Seismic noise level variation in South Korea

    Science.gov (United States)

    Sheen, D.; Shin, J.

    2008-12-01

    The variations of seismic background noise in South Korea have been investigated by means of power spectral analysis. The Korea Institute of Geoscience and Mineral Resources (KIGAM) and the Korea Meteorological Administation (KMA) have national wide seismic networks in South Korea, and, in the end of 2007, there are 30 broadband stations which have been operating for more than a year. In this study, we have estimated the power spectral density of seismic noise for 30 broadband stations from 2005 to 2007. Since we estimate PSDs from a large dataset of continuous waveform in this study, a robust PSD estimate of McNamara and Buland (2004) is used. In the frequency range 1-5 Hz, the diurnal variations of noise are observed at most of stations, which are especially larger at coastal stations and at insular than at inland. Some stations shows daily difference of diurnal variations, which represents that cultural activities contribute to the noise level of a station. The variation of number of triggered stations, however, shows that cultural noise has little influence on the detection capability of seismic network in South Korea. Seasonal variations are observed well in the range 0.1-0.5 Hz, while much less found in the frequency range 1-5 Hz. We observed that strong peaks in the range 0.1-0.5 Hz occur at the summer when Pacific typhoons are close to the Korean Peninsula.

  2. Midlatitude D region variations measured from broadband radio atmospherics

    Science.gov (United States)

    Han, Feng

    The high power, broadband very low frequency (VLF, 3--30 kHz) and extremely low frequency (ELF, 3--3000 Hz) electromagnetic waves generated by lightning discharges and propagating in the Earth-ionosphere waveguide can be used to measure the average electron density profile of the lower ionosphere (D region) across the wave propagation path due to several reflections by the upper boundary (lower ionosphere) of the waveguide. This capability makes it possible to frequently and even continuously monitor the D region electron density profile variations over geographically large regions, which are measurements that are essentially impossible by other means. These guided waves, usually called atmospherics (or sferics for short), are recorded by our sensors located near Duke University. The purpose of this work is to develop and implement algorithms to derive the variations of D region electron density profile which is modeled by two parameters (one is height and another is sharpness), by comparing the recorded sferic spectra to a series of model simulated sferic spectra from using a finite difference time domain (FDTD) code. In order to understand the time scales, magnitudes and sources for the midlatitude nighttime D region variations, we analyzed the sferic data of July and August 2005, and extracted both the height and sharpness of the D region electron density profile. The heights show large temporal variations of several kilometers on some nights and the relatively stable behavior on others. Statistical calculations indicate that the hourly average heights during the two months range between 82.0 km and 87.2 km with a mean value of 84.9 km and a standard deviation of 1.1 km. We also observed spatial variations of height as large as 2.0 km over 5 degrees latitudes on some nights, and no spatial variation on others. In addition, the measured height variations exhibited close correlations with local lightning occurrence rate on some nights but no correlation with local

  3. Variations in the Quality of Care at Large Public Hospitals in Beijing, China: A Condition-Based Outcome Approach.

    Science.gov (United States)

    Xu, Ye; Liu, Yuanli; Shu, Ting; Yang, Wei; Liang, Minghui

    2015-01-01

    Public hospitals deliver over ninety percent of all outpatient and inpatient services in China. Their quality is graded into three levels (A, B, and C) largely based on structural resources, but empirical evidence on the quality of process and outcome of care is extremely scarce. As expectations for quality care rise with higher living standards and cost of care, such evidence is urgently needed and vital to improve care and to inform future health reforms. We compiled and analyzed a multicenter database of over 4 million inpatient discharge summary records to provide a comprehensive assessment of the level and variations in clinical outcomes of hospitalization at 39 tertiary hospitals in Beijing. We assessed six outcome measures of clinical quality: in-hospital mortality rates (RSMR) for AMI, stroke, pneumonia and CABG, post-procedural complication rate (RS-CR), and failure-to-rescue rate (RS-FTR). The measures were adjusted for pre-admission patient case-mix using indirect standardization method with hierarchical linear mixed models. We found good overall quality with large variations by hospital and condition (mean/range, in %): RSMR-AMI: 6.23 (2.37-14.48), RSMR-stroke: 4.18 (3.58-4.44), RSMR-pneumonia: 7.78 (7.20-8.59), RSMR-CABG: 1.93 (1.55-2.23), RS-CR: 11.38 (9.9-12.88), and RS-FTR: 6.41 (5.17-7.58). Hospital grade was not significantly associated with any risk-adjusted outcome measures. Going to a higher grade public hospital does not always lead to better patient outcome because hospital grade only contains information about hospital structural resources. A hospital report card with some outcome measures of quality would provide valuable information to patients in choosing providers, and for regulators to identify gaps in health care quality. Reducing the variations in clinical practice and patient outcome should be a focus for policy makers in the next round of health sector reforms in China.

  4. Genomic variation landscape of the human gut microbiome

    DEFF Research Database (Denmark)

    Schloissnig, Siegfried; Arumugam, Manimozhiyan; Sunagawa, Shinichi

    2013-01-01

    Whereas large-scale efforts have rapidly advanced the understanding and practical impact of human genomic variation, the practical impact of variation is largely unexplored in the human microbiome. We therefore developed a framework for metagenomic variation analysis and applied it to 252 faecal...... polymorphism rates of 0.11 was more variable between gut microbial species than across human hosts. Subjects sampled at varying time intervals exhibited individuality and temporal stability of SNP variation patterns, despite considerable composition changes of their gut microbiota. This indicates...

  5. Opinions among Danish knee surgeons about indications to perform total knee replacement showed considerable variation

    DEFF Research Database (Denmark)

    Troelsen, Anders; Schrøder, Henrik; Husted, Henrik

    2012-01-01

    During the past decade, the incidence of primary total knee replacement (TKA) surgery in Denmark has approximately doubled. This increase could be due to weakened indications to perform TKA surgery. We aimed to investigate variation in opinions about indications to perform TKA among Danish knee...

  6. A variational analysis for large deflection of skew plates under ...

    African Journals Online (AJOL)

    In the present paper, the static behaviour of thin isotropic skew plates under uniformly distributed load is analyzed with the geometric nonlinearity of the model properly handled. A variational method based on total potential energy has been implemented through assumed displacement field. The computational work has ...

  7. On the foundation of a variational principle for decaying systems

    International Nuclear Information System (INIS)

    Szasz, G.I.

    1976-01-01

    Taking into account the circumstances that the decay of an unstable microscopic system into two fragments is established by the counting of one of the decay products in a detector, the observed exponential decay law then asserts only knowledge of the spatiotemporal behaviour of the probability density (and therewith knowledge of the decaying state) at a large finite distance from the site of decay. We therefore formulate a variational principle, of which stationary functions show this decay behaviour. In addition to the resonant wave functions there are also solutions of the variational principle, which decrease exponentially with increasing distance, i.e., functions which could be used to describe the bound states. As the time-dependent treatment shows, the decaying states cannot occur in isolation in a scattering process. The mathematical characterisation of the decaying states via a variational principle is incorporated in a theory of open physical systems. In contradiction to the variational principle of Schroedinger our principle does not provide complete knowledge of the quantum states, but this is not needed in order to describe the decay. (orig.) [de

  8. Variation in Differential and Total Cross Sections Due to Different Radial Wave Functions

    Science.gov (United States)

    Williamson, W., Jr.; Greene, T.

    1976-01-01

    Three sets of analytical wave functions are used to calculate the Na (3s---3p) transition differential and total electron excitation cross sections by Born approximations. Results show expected large variations in values. (Author/CP)

  9. Large-scale geographic variation in distribution and abundance of Australian deep-water kelp forests.

    Directory of Open Access Journals (Sweden)

    Ezequiel M Marzinelli

    Full Text Available Despite the significance of marine habitat-forming organisms, little is known about their large-scale distribution and abundance in deeper waters, where they are difficult to access. Such information is necessary to develop sound conservation and management strategies. Kelps are main habitat-formers in temperate reefs worldwide; however, these habitats are highly sensitive to environmental change. The kelp Ecklonia radiate is the major habitat-forming organism on subtidal reefs in temperate Australia. Here, we provide large-scale ecological data encompassing the latitudinal distribution along the continent of these kelp forests, which is a necessary first step towards quantitative inferences about the effects of climatic change and other stressors on these valuable habitats. We used the Autonomous Underwater Vehicle (AUV facility of Australia's Integrated Marine Observing System (IMOS to survey 157,000 m2 of seabed, of which ca 13,000 m2 were used to quantify kelp covers at multiple spatial scales (10-100 m to 100-1,000 km and depths (15-60 m across several regions ca 2-6° latitude apart along the East and West coast of Australia. We investigated the large-scale geographic variation in distribution and abundance of deep-water kelp (>15 m depth and their relationships with physical variables. Kelp cover generally increased with latitude despite great variability at smaller spatial scales. Maximum depth of kelp occurrence was 40-50 m. Kelp latitudinal distribution along the continent was most strongly related to water temperature and substratum availability. This extensive survey data, coupled with ongoing AUV missions, will allow for the detection of long-term shifts in the distribution and abundance of habitat-forming kelp and the organisms they support on a continental scale, and provide information necessary for successful implementation and management of conservation reserves.

  10. Towards Structural Analysis of Audio Recordings in the Presence of Musical Variations

    Directory of Open Access Journals (Sweden)

    Müller Meinard

    2007-01-01

    Full Text Available One major goal of structural analysis of an audio recording is to automatically extract the repetitive structure or, more generally, the musical form of the underlying piece of music. Recent approaches to this problem work well for music, where the repetitions largely agree with respect to instrumentation and tempo, as is typically the case for popular music. For other classes of music such as Western classical music, however, musically similar audio segments may exhibit significant variations in parameters such as dynamics, timbre, execution of note groups, modulation, articulation, and tempo progression. In this paper, we propose a robust and efficient algorithm for audio structure analysis, which allows to identify musically similar segments even in the presence of large variations in these parameters. To account for such variations, our main idea is to incorporate invariance at various levels simultaneously: we design a new type of statistical features to absorb microvariations, introduce an enhanced local distance measure to account for local variations, and describe a new strategy for structure extraction that can cope with the global variations. Our experimental results with classical and popular music show that our algorithm performs successfully even in the presence of significant musical variations.

  11. Leishmania-specific surface antigens show sub-genus sequence variation and immune recognition.

    Directory of Open Access Journals (Sweden)

    Daniel P Depledge

    2010-09-01

    Full Text Available A family of hydrophilic acylated surface (HASP proteins, containing extensive and variant amino acid repeats, is expressed at the plasma membrane in infective extracellular (metacyclic and intracellular (amastigote stages of Old World Leishmania species. While HASPs are antigenic in the host and can induce protective immune responses, the biological functions of these Leishmania-specific proteins remain unresolved. Previous genome analysis has suggested that parasites of the sub-genus Leishmania (Viannia have lost HASP genes from their genomes.We have used molecular and cellular methods to analyse HASP expression in New World Leishmania mexicana complex species and show that, unlike in L. major, these proteins are expressed predominantly following differentiation into amastigotes within macrophages. Further genome analysis has revealed that the L. (Viannia species, L. (V. braziliensis, does express HASP-like proteins of low amino acid similarity but with similar biochemical characteristics, from genes present on a region of chromosome 23 that is syntenic with the HASP/SHERP locus in Old World Leishmania species and the L. (L. mexicana complex. A related gene is also present in Leptomonas seymouri and this may represent the ancestral copy of these Leishmania-genus specific sequences. The L. braziliensis HASP-like proteins (named the orthologous (o HASPs are predominantly expressed on the plasma membrane in amastigotes and are recognised by immune sera taken from 4 out of 6 leishmaniasis patients tested in an endemic region of Brazil. Analysis of the repetitive domains of the oHASPs has shown considerable genetic variation in parasite isolates taken from the same patients, suggesting that antigenic change may play a role in immune recognition of this protein family.These findings confirm that antigenic hydrophilic acylated proteins are expressed from genes in the same chromosomal region in species across the genus Leishmania. These proteins are

  12. On the variation of the gravitational constant G

    International Nuclear Information System (INIS)

    De Sabbata, V.

    1980-01-01

    We consider the variation of the gravitational constant G starting from Dirac's large number hypothesis. After a brief description of the various gravitational theories which, other than General Relativity, incorporate the variation of G, we consider the geophysical and astrophysical consequences of the variation of G and the present status of the performed experiments. Finally, a short account on strong gravity is given which seems to provide a basis for Dirac's large number hypothesis. (author)

  13. Deal or No Deal? Decision Making under Risk in a Large-Stake TV Game Show and Related Experiments

    NARCIS (Netherlands)

    M.J. van den Assem (Martijn)

    2008-01-01

    textabstractThe central theme of this dissertation is the analysis of risky choice. The first two chapters analyze the choice behavior of contestants in a TV game show named “Deal or No Deal” (DOND). DOND provides a unique opportunity to study risk behavior, because it is characterized by very large

  14. 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…

  15. Large variations in ocular dimensions in a multiethnic population with similar genetic background.

    Science.gov (United States)

    Niu, Zhiqiang; Li, Jun; Zhong, Hua; Yuan, Zhonghua; Zhou, Hua; Zhang, Yang; Yuan, Yuansheng; Chen, Qin; Pan, Chen-Wei

    2016-03-07

    We aimed to describe the ethnic variations in ocular dimensions among three ethnic groups with similar genetic ancestry from mainland of China. We included 2119 ethnic Bai, 2202 ethnic Yi and 2183 ethnic Han adults aged 50 years or older in the study. Ocular dimensions including axial length (AL), anterior chamber depth (ACD), vitreous chamber depth (VCD) and lens thickness (LT) were measured using A-scan ultrasonography. Bai Chinese had longer ALs (P variations in LTs. Diabetes was associated with shallower ACDs and this association was stronger in Bai Chinese compared with Yi or Han Chinese (P for interaction = 0.02). Thicker lenses were associated with younger age (P = 0.04), male gender (P variations in cultures and lifestyles.

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

    Science.gov (United States)

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

    2017-08-01

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

  17. Winter-to-winter variations in indoor radon

    International Nuclear Information System (INIS)

    Mose, D.G.; Mushrush, G.W.; Kline, S.W.

    1989-01-01

    Indoor radon concentrations in northern Virginia and central Maryland show a strong dependence on weather. Winter tends to be associated with higher than average indoor radon, and summer with lower than average. However, compared to the winter of 1986-1987, the winter of 1987-1988 was warmer and drier. Consequently, winter-to-winter indoor radon decreased by about 25%. This winter-to-winter decrease is unexpectedly large, and simulates winter-to-summer variations that have been reported

  18. Quantum Variational Calculus

    OpenAIRE

    Malinowska , Agnieszka B.; Torres , Delfim

    2014-01-01

    International audience; Introduces readers to the treatment of the calculus of variations with q-differences and Hahn difference operators Provides the reader with the first extended treatment of quantum variational calculus Shows how the techniques described can be applied to economic models as well as other mathematical systems This Brief puts together two subjects, quantum and variational calculi by considering variational problems involving Hahn quantum operators. The main advantage of it...

  19. Anomalous variations of lithosphere magnetic field before several earthquakes

    Science.gov (United States)

    Ni, Z.; Chen, B.

    2015-12-01

    Based on the geomagnetic vector data measured each year since 2011 at more than 500 sites with a mean spatial interval of ~70km.we observed anomalous variations of lithospheric magnetic field before and after over 15 earthquakes having magnitude > 5. We find that the field in near proximity (about 50km) to the epicenter of large earthquakes shows high spatial and temporal gradients before the earthquake. Due to the low frequency of repeat measurements it is unclear when these variations occurred and how do them evolve. We point out anomalous magnetic filed using some circles with radius of 50km usually in June of each year, and then we would check whether quake will locat in our circles during one year after that time (June to next June). Now we caught 10 earthquakes of 15 main shocks having magnitude > 5, most of them located at less than10km away from our circles and some of them were in our circles. Most results show that the variations of lithosphere magnetic filed at the epicenter are different with surrending backgroud usually. When we figure out horizontal variations (vector) of lithosphere magnetic field and epicenter during one year after each June, we found half of them show that the earthquakes will locat at "the inlands in a flowing river", that means earthquakes may occur at "quiet"regions while the backgroud show character as"flow" as liquid. When we compared with GPS results, it appears that these variations of lithospere magnetic field may also correlate with displacement of earth's surface. However we do not compared with GPS results for each earthquake, we are not clear whether these anomalous variations of lithospere magnetic field may also correlate with anomalous displacement of earth's surface. Future work will include developing an automated method for identifying this type of anomalous field behavior and trying to short repeat measurement period to 6 month to try to find when these variations occur.

  20. Patterns of variation at Ustilago maydis virulence clusters 2A and 19A largely reflect the demographic history of its populations.

    Directory of Open Access Journals (Sweden)

    Ronny Kellner

    Full Text Available The maintenance of an intimate interaction between plant-biotrophic fungi and their hosts over evolutionary times involves strong selection and adaptative evolution of virulence-related genes. The highly specialised maize pathogen Ustilago maydis is assigned with a high evolutionary capability to overcome host resistances due to its high rates of sexual recombination, large population sizes and long distance dispersal. Unlike most studied fungus-plant interactions, the U. maydis - Zea mays pathosystem lacks a typical gene-for-gene interaction. It exerts a large set of secreted fungal virulence factors that are mostly organised in gene clusters. Their contribution to virulence has been experimentally demonstrated but their genetic diversity within U. maydis remains poorly understood. Here, we report on the intraspecific diversity of 34 potential virulence factor genes of U. maydis. We analysed their sequence polymorphisms in 17 isolates of U. maydis from Europe, North and Latin America. We focused on gene cluster 2A, associated with virulence attenuation, cluster 19A that is crucial for virulence, and the cluster-independent effector gene pep1. Although higher compared to four house-keeping genes, the overall levels of intraspecific genetic variation of virulence clusters 2A and 19A, and pep1 are remarkably low and commensurate to the levels of 14 studied non-virulence genes. In addition, each gene is present in all studied isolates and synteny in cluster 2A is conserved. Furthermore, 7 out of 34 virulence genes contain either no polymorphisms or only synonymous substitutions among all isolates. However, genetic variation of clusters 2A and 19A each resolve the large scale population structure of U. maydis indicating subpopulations with decreased gene flow. Hence, the genetic diversity of these virulence-related genes largely reflect the demographic history of U. maydis populations.

  1. Identifying tagging SNPs for African specific genetic variation from the African Diaspora Genome.

    Science.gov (United States)

    Johnston, Henry Richard; Hu, Yi-Juan; Gao, Jingjing; O'Connor, Timothy D; Abecasis, Gonçalo R; Wojcik, Genevieve L; Gignoux, Christopher R; Gourraud, Pierre-Antoine; Lizee, Antoine; Hansen, Mark; Genuario, Rob; Bullis, Dave; Lawley, Cindy; Kenny, Eimear E; Bustamante, Carlos; Beaty, Terri H; Mathias, Rasika A; Barnes, Kathleen C; Qin, Zhaohui S

    2017-04-21

    A primary goal of The Consortium on Asthma among African-ancestry Populations in the Americas (CAAPA) is to develop an 'African Diaspora Power Chip' (ADPC), a genotyping array consisting of tagging SNPs, useful in comprehensively identifying African specific genetic variation. This array is designed based on the novel variation identified in 642 CAAPA samples of African ancestry with high coverage whole genome sequence data (~30× depth). This novel variation extends the pattern of variation catalogued in the 1000 Genomes and Exome Sequencing Projects to a spectrum of populations representing the wide range of West African genomic diversity. These individuals from CAAPA also comprise a large swath of the African Diaspora population and incorporate historical genetic diversity covering nearly the entire Atlantic coast of the Americas. Here we show the results of designing and producing such a microchip array. This novel array covers African specific variation far better than other commercially available arrays, and will enable better GWAS analyses for researchers with individuals of African descent in their study populations. A recent study cataloging variation in continental African populations suggests this type of African-specific genotyping array is both necessary and valuable for facilitating large-scale GWAS in populations of African ancestry.

  2. Individual variation in growth in sea cucumber Apostichopus japonicus (Selenck) housed individually

    Science.gov (United States)

    Liang, Miao; Dong, Shuanglin; Gao, Qinfeng; Wang, Fang; Tian, Xiangli

    2010-09-01

    The exceptionally large individual growth variation has been previously recognized in several sea cucumber cohorts. However, there is a lack of information regarding the mechanism of such individual differences. In this study, the sea cucumber Apostichopus japonicus (Selenka) was reared individually in order to eliminate possible effects of social interaction, stocking density, etc. The results showed that there were substantial differences in growth among the sea cucumber individuals during the 100-day experiment. The special growth rate of the sea cucumber individuals differed by up to three folds (from 0.40% to 1.01%), and the coefficient of variation in body weight increased from 12.04% to 40.51%. The final wet body weight, food intake and food conversion efficiency for each sea cucumber were generally positively correlated with their initial wet body weight ( Psea cucumber individuals, largely accounting for the individual growth variation of the cohort sea cucumber. These results will provide some basic data for promoting selective breeding and farming of the sea cucumber.

  3. Intrapopulation genome size variation in D. melanogaster reflects life history variation and plasticity.

    Directory of Open Access Journals (Sweden)

    Lisa L Ellis

    2014-07-01

    Full Text Available We determined female genome sizes using flow cytometry for 211 Drosophila melanogaster sequenced inbred strains from the Drosophila Genetic Reference Panel, and found significant conspecific and intrapopulation variation in genome size. We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates. Genome size accounted for up to 23% of the variation in developmental phenotypes, but the contribution of genome size to variation in life history traits was plastic and varied according to the thermal environment. Expression data implicate differences in metabolism that correspond to genome size variation. These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species. Genome size variation accounts for a significant portion of life history variation in an environmentally dependent manner, suggesting that potential fitness effects associated with genome size variation also depend on environmental conditions.

  4. Intrapopulation Genome Size Variation in D. melanogaster Reflects Life History Variation and Plasticity

    Science.gov (United States)

    Ellis, Lisa L.; Huang, Wen; Quinn, Andrew M.; Ahuja, Astha; Alfrejd, Ben; Gomez, Francisco E.; Hjelmen, Carl E.; Moore, Kristi L.; Mackay, Trudy F. C.; Johnston, J. Spencer; Tarone, Aaron M.

    2014-01-01

    We determined female genome sizes using flow cytometry for 211 Drosophila melanogaster sequenced inbred strains from the Drosophila Genetic Reference Panel, and found significant conspecific and intrapopulation variation in genome size. We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates. Genome size accounted for up to 23% of the variation in developmental phenotypes, but the contribution of genome size to variation in life history traits was plastic and varied according to the thermal environment. Expression data implicate differences in metabolism that correspond to genome size variation. These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species. Genome size variation accounts for a significant portion of life history variation in an environmentally dependent manner, suggesting that potential fitness effects associated with genome size variation also depend on environmental conditions. PMID:25057905

  5. Frequency variations of discrete cranial traits in major human populations. III. Hyperostotic variations.

    Science.gov (United States)

    Hanihara, T; Ishida, H

    2001-09-01

    Seven discrete cranial traits usually categorised as hyperostotic characters, the medial palatine canal, hypoglossal canal bridging, precondylar tubercle, condylus tertius, jugular foramen bridging, auditory exostosis, and mylohyoid bridging were investigated in 81 major human population samples from around the world. Significant asymmetric occurrences of the bilateral traits were detected in the medial palatine canal and jugular foramen bridging in several samples. Significant intertrait associations were found between some pairs of the traits, but not consistently across the large geographical samples. The auditory exostosis showed a predominant occurrence in males. With the exception of the auditory exostosis and mylohyoid bridging in a few samples, significant sex differences were slight. The frequency distributions of the traits (except for the auditory exostosis) showed some interregional clinality and intraregional discontinuity, suggesting that genetic drift could have contributed to the observed pattern of variation.

  6. An integration of minimum local feature representation methods to recognize large variation of foods

    Science.gov (United States)

    Razali, Mohd Norhisham bin; Manshor, Noridayu; Halin, Alfian Abdul; Mustapha, Norwati; Yaakob, Razali

    2017-10-01

    Local invariant features have shown to be successful in describing object appearances for image classification tasks. Such features are robust towards occlusion and clutter and are also invariant against scale and orientation changes. This makes them suitable for classification tasks with little inter-class similarity and large intra-class difference. In this paper, we propose an integrated representation of the Speeded-Up Robust Feature (SURF) and Scale Invariant Feature Transform (SIFT) descriptors, using late fusion strategy. The proposed representation is used for food recognition from a dataset of food images with complex appearance variations. The Bag of Features (BOF) approach is employed to enhance the discriminative ability of the local features. Firstly, the individual local features are extracted to construct two kinds of visual vocabularies, representing SURF and SIFT. The visual vocabularies are then concatenated and fed into a Linear Support Vector Machine (SVM) to classify the respective food categories. Experimental results demonstrate impressive overall recognition at 82.38% classification accuracy based on the challenging UEC-Food100 dataset.

  7. Origins of Tropospheric Ozone Interannual Variation (IAV) over Reunion: A Model Investigation

    Science.gov (United States)

    Liu, Junhua; Rodriguez, Jose M.; Thompson, Anne M.; Logan, Jennifer A.; Douglass, Anne R.; Olsen, Mark A.; Steenrod, Stephen D.; Posny, Francoise

    2016-01-01

    Observations from long-term ozonesonde measurements show robust variations and trends in the evolution of ozone in the middle and upper troposphere over Reunion Island (21.1 degrees South Latitude, 55.5 degrees East Longitude) in June-August. Here we examine possible causes of the observed ozone variation at Reunion Island using hindcast simulations by the stratosphere-troposphere Global Modeling Initiative chemical transport model for 1992-2014, driven by assimilated Modern-Era Retrospective Analysis for Research and Applications (MERRA) meteorological fields. Reunion Island is at the edge of the subtropical jet, a region of strong stratospheric-tropospheric exchange. Our analysis implies that the large interannual variation (IAV) of upper tropospheric ozone over Reunion is driven by the large IAV of the stratospheric influence. The IAV of the large-scale, quasi-horizontal wind patterns also contributes to the IAV of ozone in the upper troposphere. Comparison to a simulation with constant emissions indicates that increasing emissions do not lead to the maximum trend in the middle and upper troposphere over Reunion during austral winter implied by the sonde data. The effects of increasing emission over southern Africa are limited tothe lower troposphere near the surface in August-September.

  8. Large deviations and portfolio optimization

    Science.gov (United States)

    Sornette, Didier

    Risk control and optimal diversification constitute a major focus in the finance and insurance industries as well as, more or less consciously, in our everyday life. We present a discussion of the characterization of risks and of the optimization of portfolios that starts from a simple illustrative model and ends by a general functional integral formulation. A major item is that risk, usually thought of as one-dimensional in the conventional mean-variance approach, has to be addressed by the full distribution of losses. Furthermore, the time-horizon of the investment is shown to play a major role. We show the importance of accounting for large fluctuations and use the theory of Cramér for large deviations in this context. We first treat a simple model with a single risky asset that exemplifies the distinction between the average return and the typical return and the role of large deviations in multiplicative processes, and the different optimal strategies for the investors depending on their size. We then analyze the case of assets whose price variations are distributed according to exponential laws, a situation that is found to describe daily price variations reasonably well. Several portfolio optimization strategies are presented that aim at controlling large risks. We end by extending the standard mean-variance portfolio optimization theory, first within the quasi-Gaussian approximation and then using a general formulation for non-Gaussian correlated assets in terms of the formalism of functional integrals developed in the field theory of critical phenomena.

  9. Holocene hydrologic variation at Lake Titicaca, Bolivia/Peru, and its relationship to North Atlantic climate variation

    Science.gov (United States)

    Baker, P. A.; Fritz, S. C.; Garland, J.; Ekdahl, E.

    2005-10-01

    A growing number of sites in the Northern Hemisphere show centennial- to millennial-scale climate variation that has been correlated with change in solar variability or with change in North Atlantic circulation. However, it is unclear how (or whether) these oscillations in the climate system are manifest in the Southern Hemisphere because of a lack of sites with suitably high sampling resolution. In this paper, we reconstruct the lake-level history of Lake Titicaca, using the carbon isotopic content of sedimentary organic matter, to evaluate centennial- to millennial-scale precipitation variation and its phasing relative to sites in the Northern Hemisphere. The pattern and timing of lake-level change in Lake Titicaca is similar to the ice-rafted debris record of Holocene Bond events, demonstrating a possible coupling between precipitation variation on the Altiplano and North Atlantic sea-surface temperatures (SSTs). The cold periods of the Holocene Bond events correspond with periods of increased precipitation on the Altiplano. Holocene precipitation variability on the Altiplano is anti-phased with respect to precipitation in the Northern Hemisphere monsoon region. More generally, the tropical Andes underwent large changes in precipitation on centennial-to-millennial timescales during the Holocene.

  10. Risk factors and between-hospital variation of caesarean section in Denmark

    DEFF Research Database (Denmark)

    Wehberg, Sonja; Guldberg, Rikke; Gradel, Kim Oren

    2018-01-01

    OBJECTIVES: The aim of this study was to estimate the effects of risk factors on elective and emergency caesarean section (CS) and to estimate the between-hospital variation of risk-adjusted CS proportions. DESIGN: Historical registry-based cohort study. SETTINGS AND PARTICIPANTS: The study......, for example, body mass index, parity, age and size of maternity unit and (2) risk-adjusted proportions of elective and emergency CS to evaluate between-hospital variation. RESULTS: The CS proportion was stable at 20%-21%, but showed wide variation between units, even in adjusted models. Large units performed...... CSs and one unit fewer CSs than expected. CONCLUSION: The main risk factors for elective CS were breech presentation and previous CS; for emergency CS they were breech presentation and cephalopelvic disproportion. The proportions of CS were stable during the study period. We found variation in risk...

  11. INVESTIGATION OF b-VALUE VARIATIONS IN THE AFRICAN AND PARTS OF EURASIAN PLATES

    Directory of Open Access Journals (Sweden)

    Awoyemi, M. O.

    2017-06-01

    Full Text Available Numerous earthquakes have occurred along the collision zones of the African and parts of Eurasian plates. Some of these earthquakes along these zones have generated tsunamis. To mitigate this hazard, knowledge of b-values of the Gutenberg – Richter relation for tectonic earthquakes in the African and parts of Eurasian plates is essential. The temporal variations of b-values were evaluated using sliding time windows with each window containing a total of 100 events with a view to utilizing the results as a precursor for the earthquake occurrence. The spatial variation of b-values of the study area was also delineated by dividing it into grids and calculating the b-values for each grid using constant radius and constant number of events. Results obtained from the temporal variation of b-values showed that earthquakes of large magnitudes occurred when the b-values were low while earthquakes of small magnitudes occurred when the b-values were high throughout the study period. The results of the spatial distribution of b-values also showed that earthquakes of large magnitudes occurred in areas of low b-values while earthquakes of small magnitudes occurred in areas of high b-values. The study therefore concluded that the temporal and spatial variations of b-values might be considered as a precursor for earthquake prediction.

  12. Longitudinal Variations in the Variability of Spread F Occurrence

    Science.gov (United States)

    Groves, K. M.; Bridgwood, C.; Carrano, C. S.

    2017-12-01

    The complex dynamics of the equatorial ionosphere have attracted the interest and attention of researchers for many decades. The relatively local processes that give rise to large meridional gradients have been well documented and the associated terminology has entered the common lexicon of ionospheric research (e.g., fountain effect, equatorial anomaly, bubbles, Spread F). Zonal variations have also been noted, principally at the level of determining longitudinal differences in seasonal activity patterns. Due to a historical lack of high resolution ground-based observations at low latitudes, the primary source of data for such analyses has been space-based observations from satellites such as ROCSAT, DMSP, C/NOFS that measure in situ electron density variations. An important longitudinal variation in electron density structure associated with non-migrating diurnal tides was discovered by Immel et al. in 2006 using data from the FUV sensor aboard the NASA IMAGE satellite. These satellite observations have been very helpful in identifying the structural characteristics of the equatorial ionosphere and the occurrence of Spread F, but they provide little insight into variations in scintillation features and potential differences in bubble development characteristics. Moreover space-based studies tend towards the statistics of occurrence frequency over periods of weeks to months. A recent analysis of daily spread F occurrence as determined by low latitude VHF scintillation activity shows that statistical results that are consistent with previous space-based observations, but the level of variability in the occurrence data show marked variations with longitude. For example, the American sector shows very low in-season variability while the African and Asian sectors exhibit true day-to-day variability regardless of seasonal variations. The results have significant implications for space weather as they suggest that long-term forecasts of equatorial scintillation may be

  13. Unexpectedly high genetic variation in large unisexual clumps of the subdioecious plant Honckenya peploides

    DEFF Research Database (Denmark)

    Sánchez-Vilas, Julia; Philipp, Marianne; Retuerto, Rubén

    2010-01-01

    Honckenya peploides is a subdioecious dune plant that reproduces both sexually and by clonal growth. In northwest Spain this species was found to exhibit an extreme spatial segregation of the sexes, and our objective was to investigate genetic variation in unisexual clumps. Genetic variation was ...

  14. The NANOGrav Nine-year Data Set: Measurement and Analysis of Variations in Dispersion Measures

    Energy Technology Data Exchange (ETDEWEB)

    Jones, M. L.; McLaughlin, M. A.; Lam, M. T. [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States); Cordes, J. M.; Chatterjee, S. [Department of Astronomy and Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14853 (United States); Levin, L. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Arzoumanian, Z. [Center for Research and Exploration in Space Science and Technology and X-Ray Astrophysics Laboratory, NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Crowter, K.; Gonzalez, M. E. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Demorest, P. B. [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States); Dolch, T. [Department of Physics, Hillsdale College, 33 E. College Street, Hillsdale, MI 49242 (United States); Ellis, J. A; Lazio, T. J. W. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr. Pasadena, CA 91109 (United States); Ferdman, R. D.; Fonseca, E. [Department of Physics, McGill University, 3600 rue Universite, Montreal, QC H3A 2T8 (Canada); Jones, G.; Pennucci, T. T. [Department of Physics, Columbia University, 550 W. 120th St. New York, NY 10027 (United States); Nice, D. J. [Department of Physics, Lafayette College, Easton, PA 18042 (United States); Ransom, S. M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Stinebring, D. R. [Department of Physics and Astronomy, Oberlin College, Oberlin, OH 44074 (United States); and others

    2017-06-01

    We analyze dispersion measure (DM) variations of 37 millisecond pulsars in the nine-year North American Nanohertz Observatory for Gravitational Waves (NANOGrav) data release and constrain the sources of these variations. DM variations can result from a changing distance between Earth and the pulsar, inhomogeneities in the interstellar medium, and solar effects. Variations are significant for nearly all pulsars, with characteristic timescales comparable to or even shorter than the average spacing between observations. Five pulsars have periodic annual variations, 14 pulsars have monotonically increasing or decreasing trends, and 14 pulsars show both effects. Of the four pulsars with linear trends that have line-of-sight velocity measurements, three are consistent with a changing distance and require an overdensity of free electrons local to the pulsar. Several pulsars show correlations between DM excesses and lines of sight that pass close to the Sun. Mapping of the DM variations as a function of the pulsar trajectory can identify localized interstellar medium features and, in one case, an upper limit to the size of the dispersing region of 4 au. Four pulsars show roughly Kolmogorov structure functions (SFs), and another four show SFs less steep than Kolmogorov. One pulsar has too large an uncertainty to allow comparisons. We discuss explanations for apparent departures from a Kolmogorov-like spectrum, and we show that the presence of other trends and localized features or gradients in the interstellar medium is the most likely cause.

  15. Regional variation in short distance homogamy

    OpenAIRE

    Haandrikman, Karen; van Wissen, Leo

    2011-01-01

    A third of all Dutch cohabiters choose a partner from the same municipality, so-called short distance homogamy. This article analyses the regional variation in this phenomenon, and it explains this variation in terms of geographical, socioeconomic, demographic and cultural determinants. Population register data on all new cohabiters in 2004 were used. Regression methods were employed to explain spatial patterns. Regional variation in short distance homogamy is largely explained by geographica...

  16. Evolution and interaction of large interplanetary streams

    International Nuclear Information System (INIS)

    Whang, Y.C.; Burlaga, L.F.

    1985-02-01

    A computer simulation for the evolution and interaction of large interplanetary streams based on multi-spacecraft observations and an unsteady, one-dimensional MHD model is presented. Two events, each observed by two or more spacecraft separated by a distance of the order of 10 AU, were studied. The first simulation is based on the plasma and magnetic field observations made by two radially-aligned spacecraft. The second simulation is based on an event observed first by Helios-1 in May 1980 near 0.6 AU and later by Voyager-1 in June 1980 at 8.1 AU. These examples show that the dynamical evolution of large-scale solar wind structures is dominated by the shock process, including the formation, collision, and merging of shocks. The interaction of shocks with stream structures also causes a drastic decrease in the amplitude of the solar wind speed variation with increasing heliocentric distance, and as a result of interactions there is a large variation of shock-strengths and shock-speeds. The simulation results shed light on the interpretation for the interaction and evolution of large interplanetary streams. Observations were made along a few limited trajectories, but simulation results can supplement these by providing the detailed evolution process for large-scale solar wind structures in the vast region not directly observed. The use of a quantitative nonlinear simulation model including shock merging process is crucial in the interpretation of data obtained in the outer heliosphere

  17. Variations in pollinator density and impacts on large cardamom (Amomum subulatum Roxb. crop yield in Sikkim Himalaya, India

    Directory of Open Access Journals (Sweden)

    Kailash S. Gaira

    2016-03-01

    Full Text Available Large cardamom (Amomum subulatum Roxb., a perennial cash crop, cultivated under an agroforestry system in the eastern Himalaya of India, is well recognized as a pollination-dependent crop. Observations on pollinator abundance in Mamlay watershed of Sikkim Himalaya were collected during the blooming season to evaluate the pollinator abundance across sites and time frames, and impact of pollinator abundance on crop yield from 2010 to 2012. The results revealed that the bumblebees and honeybees are most frequent visitors of large cardamom flowers. The abundance of honeybees, however, varied between sites for the years 2010–2012, while that of bumblebees varied for the years 2011 and 2012. The abundance of honeybees resulted in a variation within time frames for 2010 and 2011, while that of bumblebees varied for 2010 and 2012 (p<0.01. The density of pollinators correlated positively with the number of flowers of the target crop. The impact of pollinator abundance revealed that the increasing bumblebee visitation resulted in a higher yield of the crop (i.e. 17–41 g/plant and the increasing abundance of all bees (21–41 g/plant was significant (p<0.03. Therefore, the study concluded that the large cardamom yield is sensitive to pollinator abundance and there is a need for adopting the best pollinator conservation and management practices toward sustaining the yield of large cardamom.

  18. VESPA: Very large-scale Evolutionary and Selective Pressure Analyses

    Directory of Open Access Journals (Sweden)

    Andrew E. Webb

    2017-06-01

    Full Text Available Background Large-scale molecular evolutionary analyses of protein coding sequences requires a number of preparatory inter-related steps from finding gene families, to generating alignments and phylogenetic trees and assessing selective pressure variation. Each phase of these analyses can represent significant challenges, particularly when working with entire proteomes (all protein coding sequences in a genome from a large number of species. Methods We present VESPA, software capable of automating a selective pressure analysis using codeML in addition to the preparatory analyses and summary statistics. VESPA is written in python and Perl and is designed to run within a UNIX environment. Results We have benchmarked VESPA and our results show that the method is consistent, performs well on both large scale and smaller scale datasets, and produces results in line with previously published datasets. Discussion Large-scale gene family identification, sequence alignment, and phylogeny reconstruction are all important aspects of large-scale molecular evolutionary analyses. VESPA provides flexible software for simplifying these processes along with downstream selective pressure variation analyses. The software automatically interprets results from codeML and produces simplified summary files to assist the user in better understanding the results. VESPA may be found at the following website: http://www.mol-evol.org/VESPA.

  19. Interannual variation of annual precipitation and urban effect on precipitation in the Beijing region

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The large scale character of the interannual variation of precipitation and the urban effect on local annual precipitation anomaly are investigated in this paper based on the 1960-2000 annual precipitation observations at 20 stations in the Beijing region. The results show that: the annual precipitation in the Beijing region possesses the large scale variation character with the linear trend of - 1.197/10 yr, which corresponds to a total reduction of 27.82 mm in annual precipitation in the 41 years; the local annual precipitation anomalies (percent of the normal 1960-2000) show a positive center near the urban area, i.e. urban precipitation island (UPI), whose intensity increases with the linear trend of 0. 6621%/10 yr, opposite to the interannual trend of large scale precipitation over the Beijing region; changes in the UPI are also associated with the intensity of synoptic processes of precipitation, and when the synoptic processes are strong (wet years), the intensity of UPI strengthens, while the synoptic processes are weak (dry years), and the UPI disappears in the Beijing region.

  20. Modeling stimulus variation in three common implicit attitude tasks.

    Science.gov (United States)

    Wolsiefer, Katie; Westfall, Jacob; Judd, Charles M

    2017-08-01

    We explored the consequences of ignoring the sampling variation due to stimuli in the domain of implicit attitudes. A large literature in psycholinguistics has examined the statistical treatment of random stimulus materials, but the recommendations from this literature have not been applied to the social psychological literature on implicit attitudes. This is partly because of inherent complications in applying crossed random-effect models to some of the most common implicit attitude tasks, and partly because no work to date has demonstrated that random stimulus variation is in fact consequential in implicit attitude measurement. We addressed this problem by laying out statistically appropriate and practically feasible crossed random-effect models for three of the most commonly used implicit attitude measures-the Implicit Association Test, affect misattribution procedure, and evaluative priming task-and then applying these models to large datasets (average N = 3,206) that assess participants' implicit attitudes toward race, politics, and self-esteem. We showed that the test statistics from the traditional analyses are substantially (about 60 %) inflated relative to the more-appropriate analyses that incorporate stimulus variation. Because all three tasks used the same stimulus words and faces, we could also meaningfully compare the relative contributions of stimulus variation across the tasks. In an appendix, we give syntax in R, SAS, and SPSS for fitting the recommended crossed random-effects models to data from all three tasks, as well as instructions on how to structure the data file.

  1. "Life history space": a multivariate analysis of life history variation in extant and extinct Malagasy lemurs.

    Science.gov (United States)

    Catlett, Kierstin K; Schwartz, Gary T; Godfrey, Laurie R; Jungers, William L

    2010-07-01

    Studies of primate life history variation are constrained by the fact that all large-bodied extant primates are haplorhines. However, large-bodied strepsirrhines recently existed. If we can extract life history information from their skeletons, these species can contribute to our understanding of primate life history variation. This is particularly important in light of new critiques of the classic "fast-slow continuum" as a descriptor of variation in life history profiles across mammals in general. We use established dental histological methods to estimate gestation length and age at weaning for five extinct lemur species. On the basis of these estimates, we reconstruct minimum interbirth intervals and maximum reproductive rates. We utilize principal components analysis to create a multivariate "life history space" that captures the relationships among reproductive parameters and brain and body size in extinct and extant lemurs. Our data show that, whereas large-bodied extinct lemurs can be described as "slow" in some fashion, they also varied greatly in their life history profiles. Those with relatively large brains also weaned their offspring late and had long interbirth intervals. These were not the largest of extinct lemurs. Thus, we distinguish size-related life history variation from variation that linked more strongly to ecological factors. Because all lemur species larger than 10 kg, regardless of life history profile, succumbed to extinction after humans arrived in Madagascar, we argue that large body size increased the probability of extinction independently of reproductive rate. We also provide some evidence that, among lemurs, brain size predicts reproductive rate better than body size. (c) 2010 Wiley-Liss, Inc.

  2. Measurement and Socio-Demographic Variation of Social Capital in a Large Population-Based Survey

    Science.gov (United States)

    Nieminen, Tarja; Martelin, Tuija; Koskinen, Seppo; Simpura, Jussi; Alanen, Erkki; Harkanen, Tommi; Aromaa, Arpo

    2008-01-01

    Objectives: The main objective of this study was to describe the variation of individual social capital according to socio-demographic factors, and to develop a suitable way to measure social capital for this purpose. The similarity of socio-demographic variation between the genders was also assessed. Data and methods: The study applied…

  3. Predicting Variation of Folk Songs: A Corpus Analysis Study on the Memorability of Melodies

    Directory of Open Access Journals (Sweden)

    Berit Janssen

    2017-04-01

    Full Text Available We present a hypothesis-driven study on the variation of melody phrases in a collection of Dutch folk songs. We investigate the variation of phrases within the folk songs through a pattern matching method which detects occurrences of these phrases within folk song variants, and ask the question: do the phrases which show less variation have different properties than those which do? We hypothesize that theories on melody recall may predict variation, and as such, investigate phrase length, the position and number of repetitions of a given phrase in the melody in which it occurs, as well as expectancy and motif repetivity. We show that all of these predictors account for the observed variation to a moderate degree, and that, as hypothesized, those phrases vary less which are rather short, contain highly expected melodic material, occur relatively early in the melody, and contain small pitch intervals. A large portion of the variance is left unexplained by the current model, however, which leads us to a discussion of future approaches to study memorability of melodies.

  4. Variations in large-scale tropical cyclone genesis factors over the western North Pacific in the PMIP3 last millennium simulations

    Science.gov (United States)

    Yan, Qing; Wei, Ting; Zhang, Zhongshi

    2017-02-01

    Investigation of past tropical cyclone (TC) activity in the Western North Pacific (WNP) is potentially helpful to enable better understanding of future TC behaviors. In this study, we examine variations in large-scale environmental factors important to TC genesis in the last millennium simulations from the Paleoclimate Modelling Intercomparison Project Phase 3 (PMIP3). The results show that potential intensity, a theoretical prediction of the maximum TC intensity, is increased relative to the last millennium in the north part of the WNP in the Medieval Climate Anomaly (MCA; 950-1200 AD) while it is decreased in the Little Ice Age (LIA; 1600-1850 AD). Vertical wind shear that generally inhibits TC genesis is enhanced (reduced) to the south of 20°N and is reduced (enhanced) to the north in the MCA (LIA). Relative humidity (at 600 hPa) that measures the mid-tropospheric moisture content broadly shows an increase (decrease) in the MCA (LIA). A genesis potential index indicates that conditions are generally favorable (unfavorable) for TC formation in the WNP in the MCA (LIA), especially in the northern part. Taking changes in steering flows into account, there may be an increasing (decreasing) favorability for storm strikes in East Asia in the MCA (LIA). The estimated TC activity is consistent with the geological proxies in Japan, but contradicts with the typhoon records in southern China and Taiwan. This model-data discrepancy is attributed to the limitations in both simulations and reconstructions.

  5. Les fluctuations du champ magnétique terrestre : des variations séculaires récentes aux renversements

    OpenAIRE

    FANJAT , Gregory

    2012-01-01

    The Earth's magnetic field shows a large range of temporal variations from the year to several million years. I studied during my PhD thesis several aspects of these fluctuations, from recent secular variations to reversals. The first part of my manuscript deals with archeomagnetism, a discipline that allows to track the temporal variations of the Earth's magnetic field through millennia, mainly from archeological materials. I studied two sets of samples , one from Greece (Neolithic period 68...

  6. The African Genome Variation Project shapes medical genetics in Africa

    Science.gov (United States)

    Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O.; Choudhury, Ananyo; Ritchie, Graham R. S.; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N.; Young, Elizabeth H.; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P.; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A.; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S.

    2014-01-01

    Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterisation of African genetic diversity is needed. The African Genome Variation Project (AGVP) provides a resource to help design, implement and interpret genomic studies in sub-Saharan Africa (SSA) and worldwide. The AGVP represents dense genotypes from 1,481 and whole genome sequences (WGS) from 320 individuals across SSA. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across SSA. We identify new loci under selection, including for malaria and hypertension. We show that modern imputation panels can identify association signals at highly differentiated loci across populations in SSA. Using WGS, we show further improvement in imputation accuracy supporting efforts for large-scale sequencing of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa, showing for the first time that such designs are feasible. PMID:25470054

  7. The use of Adomian decomposition method for solving problems in calculus of variations

    Directory of Open Access Journals (Sweden)

    Mehdi Dehghan

    2006-01-01

    Full Text Available In this paper, a numerical method is presented for finding the solution of some variational problems. The main objective is to find the solution of an ordinary differential equation which arises from the variational problem. This work is done using Adomian decomposition method which is a powerful tool for solving large amount of problems. In this approach, the solution is found in the form of a convergent power series with easily computed components. To show the efficiency of the method, numerical results are presented.

  8. The contribution of additive genetic variation to personality variation: heritability of personality.

    Science.gov (United States)

    Dochtermann, Ned A; Schwab, Tori; Sih, Andrew

    2015-01-07

    Individual animals frequently exhibit repeatable differences from other members of their population, differences now commonly referred to as 'animal personality'. Personality differences can arise, for example, from differences in permanent environmental effects--including parental and epigenetic contributors--and the effect of additive genetic variation. Although several studies have evaluated the heritability of behaviour, less is known about general patterns of heritability and additive genetic variation in animal personality. As overall variation in behaviour includes both the among-individual differences that reflect different personalities and temporary environmental effects, it is possible for personality to be largely genetically influenced even when heritability of behaviour per se is quite low. The relative contribution of additive genetic variation to personality variation can be estimated whenever both repeatability and heritability are estimated for the same data. Using published estimates to address this issue, we found that approximately 52% of animal personality variation was attributable to additive genetic variation. Thus, while the heritability of behaviour is often moderate or low, the heritability of personality is much higher. Our results therefore (i) demonstrate that genetic differences are likely to be a major contributor to variation in animal personality and (ii) support the phenotypic gambit: that evolutionary inferences drawn from repeatability estimates may often be justified. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  9. Curbing variations in packaging process through Six Sigma way in a large-scale food-processing industry

    Science.gov (United States)

    Desai, Darshak A.; Kotadiya, Parth; Makwana, Nikheel; Patel, Sonalinkumar

    2015-03-01

    Indian industries need overall operational excellence for sustainable profitability and growth in the present age of global competitiveness. Among different quality and productivity improvement techniques, Six Sigma has emerged as one of the most effective breakthrough improvement strategies. Though Indian industries are exploring this improvement methodology to their advantage and reaping the benefits, not much has been presented and published regarding experience of Six Sigma in the food-processing industries. This paper is an effort to exemplify the application of Six Sigma quality improvement drive to one of the large-scale food-processing sectors in India. The paper discusses the phase wiz implementation of define, measure, analyze, improve, and control (DMAIC) on one of the chronic problems, variations in the weight of milk powder pouch. The paper wraps up with the improvements achieved and projected bottom-line gain to the unit by application of Six Sigma methodology.

  10. Variations in pollen counts largely explained by climate and weather

    Science.gov (United States)

    Jung, Stephan; Damialis, Athanasios; Estrella, Nicole; Jochner, Susanne; Menzel, Annette

    2017-04-01

    trap can be used to detect short-, middle- and long-range pollen transport. The pollen trap in Garmisch-Partenkirchen is located in the valley below Zugspitze making these two stations suitable for a direct comparison. First results show that the total amount of pollen at Schneefernerhaus for Plantago, Quercus, Poaceae, Cupressaceae, Cyperaceae and Betula is only about 20% in comparison to Garmisch. Furthermore there are daily differences in the pollen counts in yearly sum between morning (24:00 -12:00) and afternoon (12:00- 24:00). This phenomenon might be caused by diurnal climatic variations in the boundary layer as well as local mountain wind systems (changing wind direction from morning to afternoon time). Additionally pollen counts were linked to weather data recorded by the German Meteorological Service and local climate stations. Results indicate that the duration of precipitation events is a major factor of influence concerning the counted pollen. With increasing duration of a rain event pollen counts are decreasing.

  11. Geographical variation in egg mass and egg content in a passerine bird.

    Directory of Open Access Journals (Sweden)

    Suvi Ruuskanen

    Full Text Available Reproductive, phenotypic and life-history traits in many animal and plant taxa show geographic variation, indicating spatial variation in selection regimes. Maternal deposition to avian eggs, such as hormones, antibodies and antioxidants, critically affect development of the offspring, with long-lasting effects on the phenotype and fitness. Little is however known about large-scale geographical patterns of variation in maternal deposition to eggs. We studied geographical variation in egg components of a passerine bird, the pied flycatcher (Ficedula hypoleuca, by collecting samples from 16 populations and measuring egg and yolk mass, albumen lysozyme activity, yolk immunoglobulins, yolk androgens and yolk total carotenoids. We found significant variation among populations in most egg components, but ca. 90% of the variation was among individuals within populations. Population however explained 40% of the variation in carotenoid levels. In contrast to our hypothesis, we found geographical trends only in carotenoids, but not in any of the other egg components. Our results thus suggest high within-population variation and leave little scope for local adaptation and genetic differentiation in deposition of different egg components. The role of these maternally-derived resources in evolutionary change should be further investigated.

  12. Large-scale hydrology in Europe : observed patterns and model performance

    Energy Technology Data Exchange (ETDEWEB)

    Gudmundsson, Lukas

    2011-06-15

    In a changing climate, terrestrial water storages are of great interest as water availability impacts key aspects of ecosystem functioning. Thus, a better understanding of the variations of wet and dry periods will contribute to fully grasp processes of the earth system such as nutrient cycling and vegetation dynamics. Currently, river runoff from small, nearly natural, catchments is one of the few variables of the terrestrial water balance that is regularly monitored with detailed spatial and temporal coverage on large scales. River runoff, therefore, provides a foundation to approach European hydrology with respect to observed patterns on large scales, with regard to the ability of models to capture these.The analysis of observed river flow from small catchments, focused on the identification and description of spatial patterns of simultaneous temporal variations of runoff. These are dominated by large-scale variations of climatic variables but also altered by catchment processes. It was shown that time series of annual low, mean and high flows follow the same atmospheric drivers. The observation that high flows are more closely coupled to large scale atmospheric drivers than low flows, indicates the increasing influence of catchment properties on runoff under dry conditions. Further, it was shown that the low-frequency variability of European runoff is dominated by two opposing centres of simultaneous variations, such that dry years in the north are accompanied by wet years in the south.Large-scale hydrological models are simplified representations of our current perception of the terrestrial water balance on large scales. Quantification of the models strengths and weaknesses is the prerequisite for a reliable interpretation of simulation results. Model evaluations may also enable to detect shortcomings with model assumptions and thus enable a refinement of the current perception of hydrological systems. The ability of a multi model ensemble of nine large

  13. Variations in pCO2 during summer in the surface water of an unproductive lake in northern Sweden

    International Nuclear Information System (INIS)

    Jonsson, A.; Aaberg, J.; Jansson, M.

    2007-01-01

    Unproductive lakes are generally supersaturated with carbon dioxide (CO 2 ) and emit CO 2 to the atmosphere continuously during ice-free periods. However, temporal variation of the partial pressure of CO 2 (pCO 2 ) and thus of CO 2 evasion to atmosphere is poorly documented. We therefore carried out temporally high-resolution (every 6 h) measurements of the pCO 2 using an automated logger system in the surface water of a subarctic, unproductive, lake in the birch forest belt. The study period was June-September 2004. We found that the pCO 2 showed large seasonal variation, but low daily variation. The seasonal variation was likely mainly caused by variations in input and mineralization of allochthonous organic matter. Stratification depth probably also influenced pCO 2 of the surface water by controlling the volume in which mineralization of dissolved organic carbon (DOC) occurred. In lakes, with large variations in pCO 2 , as in our study lake a high (weekly) sampling intensity is recommended for obtaining accurate estimates of the evasion of CO 2

  14. Explaining growth variation over large spatial scales: Effects of temperature and food on walleye growth

    DEFF Research Database (Denmark)

    Mosgaard, Thomas; Venturelli, Paul; Lester, Nigel P.

    2012-01-01

    freshwater fish species in North America. We then use length at age data from yellow perch (Perca flavescens) to identify the mechanisms behind the remaining variation in the length at age – temperature relationship for walleye. A positive perch – walleye relationship indicates that the mechanism behind......Most fishes exhibit strong spatial variation in growth. Because fish growth and production are tightly linked, quantifying and explaining variation in growth can mean the difference between successful management and unforeseen collapse. However, disentangling the factors that are responsible...

  15. Large Torque Variations in Two Soft Gamma Repeaters

    NARCIS (Netherlands)

    Woods, P.M.; Kouveliotou, C.; Göğüş, E.; Finger, M.H.; Swank, J.; Markwardt, C.B.; Hurley, K.; van der Klis, M.

    2002-01-01

    We have monitored the pulse frequencies of the two soft gamma repeaters SGR 1806-20 and SGR 1900+14 through the beginning of year 2001 using primarily Rossi X-Ray Timing Explorer Proportional Counter Array observations. In both sources, we observe large changes in the spin-down torque up to a factor

  16. Variation in nesting behavior of eight species of spider mites, Stigmaeopsis having sociality

    Science.gov (United States)

    Saito, Yutaka; Zhang, Yan-Xuan; Mori, Kotaro; Ito, Katsura; Sato, Yukie; Chittenden, Anthony R.; Lin, Jian-Zhen; Chae, Younghae; Sakagami, Takane; Sahara, Ken

    2016-10-01

    Nesting behavior is considered to be an important element of social living in animals. The spider mites belonging to the genus Stigmaeopsis spend their lives within nests produced from silk threads. Several of these species show cooperative sociality, while the others are subsocial. In order to identify the origins of this social behavior, comparisons of nest sizes, nesting behaviors (making nests continuously or separately), and their associated traits (fecal deposition patterns) were made for eight cogeneric Stigmaeopsis species showing various levels of social development. All of these species inhabit bamboo plants (Poaceae). We initially addressed the proximate factor of nest size variation. The variation in nest size of the eight species corresponded well with the variation in dorsal seta sc1 length, suggesting that nest size variation among species may have a genetic basis. The time spent within a nest (nest duration) increased with nest size on the respective host plants. Nest arrangement patterns varied among species showing different sized nests: Large nest builders continuously extended their nests, while middle and small nest-building species built new separate nests, which resulted in different social interaction times among species, and is thought to be closely related to social development. Fecal deposition behaviors also varied among Stigmaeopsis species, suggesting diversity in anti-predatory adaptations. Finally, we discuss how the variation in sociality observed within this genus is likely the result of nest size variation that initially evolved as anti-predator strategies.

  17. Polar front associated variation in prokaryotic community structure in Arctic shelf seafloor.

    Science.gov (United States)

    Nguyen, Tan T; Landfald, Bjarne

    2015-01-01

    Spatial variations in composition of marine microbial communities and its causes have largely been disclosed in studies comprising rather large environmental and spatial differences. In the present study, we explored if a moderate but temporally permanent climatic division within a contiguous arctic shelf seafloor was traceable in the diversity patterns of its bacterial and archaeal communities. Soft bottom sediment samples were collected at 10 geographical locations, spanning spatial distances of up to 640 km, transecting the oceanic polar front in the Barents Sea. The northern sampling sites were generally colder, less saline, shallower, and showed higher concentrations of freshly sedimented phytopigments compared to the southern study locations. Sampling sites depicted low variation in relative abundances of taxa at class level, with persistent numerical dominance by lineages of Gamma- and Deltaproteobacteria (57-66% of bacterial sequence reads). The Archaea, which constituted 0.7-1.8% of 16S rRNA gene copy numbers in the sediment, were overwhelmingly (85.8%) affiliated with the Thaumarchaeota. Beta-diversity analyses showed the environmental variations throughout the sampling range to have a stronger impact on the structuring of both the bacterial and archaeal communities than spatial effects. While bacterial communities were significantly influenced by the combined effect of several weakly selective environmental differences, including temperature, archaeal communities appeared to be more uniquely structured by the level of freshly sedimented phytopigments.

  18. Large variations in diurnal and seasonal patterns of sap flux among Aleppo pine trees in semi-arid forest reflect tree-scale hydraulic adjustments

    Science.gov (United States)

    Preisler, Yakir; Tatarinov, Fyodor; Rohatyn, Shani; Rotenberg, Eyal; Grünzweig, José M.; Klein, Tamir; Yakir, Dan

    2015-04-01

    Adjustments and adaptations of trees to drought vary across different biomes, species and habitats, with important implications for tree mortality and forest dieback associated with global climate change. The aim of this study was to investigate possible links between the patterns of variations in water flux dynamics and drought resistance in Aleppo pine (Pinus halepensis) trees in a semi-arid stand (Yatir forest, Israel). We measured sap flow (SF) and variations in stem diameter, complemented with short-term campaigns of leaf-scale measurements of water vapour and CO2 gas exchange, branch water potential and hydraulic conductivity, as well as eddy flux measurements of evapotranspiration (ET) from a permanent flux tower at the site. SF rates were well synchronized with ET, reaching maximum rates during midday in all trees during the rainy season (Dec-Apr). However, during the dry season (May-Nov), the daily trend in the rates of SF greatly varied among trees, allowing classification into three tree classes: 1) trees with SF maximum rate constantly occurring in mid-day (12:00-13:00); 2)trees showing a shift to an early morning SF peak (04:00-06:00); and 3) trees shifting their daily SF peak to the evening (16:00-18:00). This classification did not change during the four years study period, between 2010 and 2014. Checking for correlation of tree parameters as DBH, tree height, crown size, and competition indices with rates of SF, indicated that timing of maximum SF in summer was mainly related to tree size (DBH), when large trees tended to have a later SF maximum. Dendrometer measurements indicated that large trees (high DBH) had maximum daily diameter in the morning during summer and winter, while small trees typically had maximum daily diameter during midday and afternoon in winter and summer, respectively. Leaf-scale transpiration (T) measurements showed typical morning peak in all trees, and another peak in the afternoon in large trees only. Different diurnal

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

    Science.gov (United States)

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

    2015-01-01

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

  20. Genic intolerance to functional variation and the interpretation of personal genomes.

    Directory of Open Access Journals (Sweden)

    Slavé Petrovski

    Full Text Available A central challenge in interpreting personal genomes is determining which mutations most likely influence disease. Although progress has been made in scoring the functional impact of individual mutations, the characteristics of the genes in which those mutations are found remain largely unexplored. For example, genes known to carry few common functional variants in healthy individuals may be judged more likely to cause certain kinds of disease than genes known to carry many such variants. Until now, however, it has not been possible to develop a quantitative assessment of how well genes tolerate functional genetic variation on a genome-wide scale. Here we describe an effort that uses sequence data from 6503 whole exome sequences made available by the NHLBI Exome Sequencing Project (ESP. Specifically, we develop an intolerance scoring system that assesses whether genes have relatively more or less functional genetic variation than expected based on the apparently neutral variation found in the gene. To illustrate the utility of this intolerance score, we show that genes responsible for Mendelian diseases are significantly more intolerant to functional genetic variation than genes that do not cause any known disease, but with striking variation in intolerance among genes causing different classes of genetic disease. We conclude by showing that use of an intolerance ranking system can aid in interpreting personal genomes and identifying pathogenic mutations.

  1. The large deviation approach to statistical mechanics

    International Nuclear Information System (INIS)

    Touchette, Hugo

    2009-01-01

    The theory of large deviations is concerned with the exponential decay of probabilities of large fluctuations in random systems. These probabilities are important in many fields of study, including statistics, finance, and engineering, as they often yield valuable information about the large fluctuations of a random system around its most probable state or trajectory. In the context of equilibrium statistical mechanics, the theory of large deviations provides exponential-order estimates of probabilities that refine and generalize Einstein's theory of fluctuations. This review explores this and other connections between large deviation theory and statistical mechanics, in an effort to show that the mathematical language of statistical mechanics is the language of large deviation theory. The first part of the review presents the basics of large deviation theory, and works out many of its classical applications related to sums of random variables and Markov processes. The second part goes through many problems and results of statistical mechanics, and shows how these can be formulated and derived within the context of large deviation theory. The problems and results treated cover a wide range of physical systems, including equilibrium many-particle systems, noise-perturbed dynamics, nonequilibrium systems, as well as multifractals, disordered systems, and chaotic systems. This review also covers many fundamental aspects of statistical mechanics, such as the derivation of variational principles characterizing equilibrium and nonequilibrium states, the breaking of the Legendre transform for nonconcave entropies, and the characterization of nonequilibrium fluctuations through fluctuation relations.

  2. The large deviation approach to statistical mechanics

    Science.gov (United States)

    Touchette, Hugo

    2009-07-01

    The theory of large deviations is concerned with the exponential decay of probabilities of large fluctuations in random systems. These probabilities are important in many fields of study, including statistics, finance, and engineering, as they often yield valuable information about the large fluctuations of a random system around its most probable state or trajectory. In the context of equilibrium statistical mechanics, the theory of large deviations provides exponential-order estimates of probabilities that refine and generalize Einstein’s theory of fluctuations. This review explores this and other connections between large deviation theory and statistical mechanics, in an effort to show that the mathematical language of statistical mechanics is the language of large deviation theory. The first part of the review presents the basics of large deviation theory, and works out many of its classical applications related to sums of random variables and Markov processes. The second part goes through many problems and results of statistical mechanics, and shows how these can be formulated and derived within the context of large deviation theory. The problems and results treated cover a wide range of physical systems, including equilibrium many-particle systems, noise-perturbed dynamics, nonequilibrium systems, as well as multifractals, disordered systems, and chaotic systems. This review also covers many fundamental aspects of statistical mechanics, such as the derivation of variational principles characterizing equilibrium and nonequilibrium states, the breaking of the Legendre transform for nonconcave entropies, and the characterization of nonequilibrium fluctuations through fluctuation relations.

  3. BOLE WATER CONTENT SHOWS LITTLE SEASONAL VARIATION IN CENTURY-OLD DOUGLAS-FIR TREES

    Science.gov (United States)

    Purportedly, large Douglas-fir trees in the American Pacific Northwest use water stored in bole tissues to ameliorate the effects of seasonal summer drought, the water content of bole tissues being drawn down over the summer months and replenished during the winter. Continuous mo...

  4. Relevant Spatial Scales of Chemical Variation in Aplysina aerophoba

    Directory of Open Access Journals (Sweden)

    Oriol Sacristan-Soriano

    2011-11-01

    Full Text Available Understanding the scale at which natural products vary the most is critical because it sheds light on the type of factors that regulate their production. The sponge Aplysina aerophoba is a common Mediterranean sponge inhabiting shallow waters in the Mediterranean and its area of influence in Atlantic Ocean. This species contains large concentrations of brominated alkaloids (BAs that play a number of ecological roles in nature. Our research investigates the ecological variation in BAs of A. aerophoba from a scale of hundred of meters to thousand kilometers. We used a nested design to sample sponges from two geographically distinct regions (Canary Islands and Mediterranean, over 2500 km, with two zones within each region (less than 50 km, two locations within each zone (less than 5 km, and two sites within each location (less than 500 m. We used high-performance liquid chromatography to quantify multiple BAs and a spectrophotometer to quantify chlorophyll a (Chl a. Our results show a striking degree of variation in both natural products and Chl a content. Significant variation in Chl a content occurred at the largest and smallest geographic scales. The variation patterns of BAs also occurred at the largest and smallest scales, but varied depending on which BA was analyzed. Concentrations of Chl a and isofistularin-3 were negatively correlated, suggesting that symbionts may impact the concentration of some of these compounds. Our results underline the complex control of the production of secondary metabolites, with factors acting at both small and large geographic scales affecting the production of multiple secondary metabolites.

  5. Identification of the characteristics of motorcycle and scooter tyres in the presence of large variations in inflation pressure

    Science.gov (United States)

    Cossalter, V.; Doria, A.; Giolo, E.; Taraborrelli, L.; Massaro, M.

    2014-10-01

    Stability and safety of road vehicles are largely affected by tyre properties. Single-track vehicles are characterised by weakly damped modes of vibration (weave and wobble) and therefore this phenomenon is even more important. This article focuses on the study of both steady-state and transient properties of motorcycle and scooter tyres in the presence of very low and very high inflation pressures. The steady-state properties are defined as lateral forces (side-slip and camber forces) and yaw torques (self-aligning and twisting). The transient properties are described in terms of relaxation length, which represents the distance needed to reach a certain percentage of the steady-state value of the tyre force. Experimental tests are carried out on a specific rotating disk machine. Three sets of tyres are analysed. Steady-state properties are measured by increasing step by step the values of camber and side-slip angles. Transient properties are studied carrying out tests with harmonic side-slip excitation and measuring the phase lag between the excitation (input) and the tyre force (output). Experimental results show important variations in tyre properties with inflation pressure with general trends of all the tested tyres and particular features related to the tyre's geometry. After the analysis and discussion of experimental results, the measured data are fitted by means of a specific version of the Magic Formula. The dependence of the Magic Formula's coefficients on inflation pressure is analysed and interpolation curves are given.

  6. Copy number variation analysis of matched ovarian primary tumors and peritoneal metastasis.

    Directory of Open Access Journals (Sweden)

    Joel A Malek

    Full Text Available Ovarian cancer is the most deadly gynecological cancer. The high rate of mortality is due to the large tumor burden with extensive metastatic lesion of the abdominal cavity. Despite initial chemosensitivity and improved surgical procedures, abdominal recurrence remains an issue and results in patients' poor prognosis. Transcriptomic and genetic studies have revealed significant genome pathologies in the primary tumors and yielded important information regarding carcinogenesis. There are, however, few studies on genetic alterations and their consequences in peritoneal metastatic tumors when compared to their matched ovarian primary tumors. We used high-density SNP arrays to investigate copy number variations in matched primary and metastatic ovarian cancer from 9 patients. Here we show that copy number variations acquired by ovarian tumors are significantly different between matched primary and metastatic tumors and these are likely due to different functional requirements. We show that these copy number variations clearly differentially affect specific pathways including the JAK/STAT and cytokine signaling pathways. While many have shown complex involvement of cytokines in the ovarian cancer environment we provide evidence that ovarian tumors have specific copy number variation differences in many of these genes.

  7. Genetic variation of common walnut (Juglans regia in Piedmont, Northwestern Italy

    Directory of Open Access Journals (Sweden)

    Ferrazzini D

    2007-12-01

    Full Text Available The European or common walnut is a large tree prized as a multipurpose species: it provides valuable timber and produces a high-quality edible nut. The diffusion of the species in Italy has been largely influenced by the human activity, mainly through germplasm movement, selection of genotypes most suited for wood or fruit production and adaptation induced on fruit crop reproductive materials. As a consequence, genetic variability has been reduced, so that programs aimed at its preservation appear of the utmost importance. 104 walnut plants growing in Piedmont, northwestern Italy, were investigated through genetic variation scored at RAPD loci, yielded by PCR amplification of 10 decamer primers. Among the 101 studied loci, only 53 were polymorphic, showing a low level of genetic variation within the studied material. Genetic differentiation was estimated both at individual and geographical area level. Only in few cases trees growing in the same area showed to be genetically similar, while the differentiation between areas accounted for about 10% of the total variation, according to AMOVA. No significant correlation was found between genetic and geographic distances. The results of the study showed that also in Piedmont (such as it was already demonstrated in other parts of Italy the distribution of common walnut is a direct consequence of the human activity. The selection of individual trees, to be used as basic materials for seed supply, should therefore be based mainly on phenotypic traits, rather than ecological features of the location: in species characterized by artificial diffusion, the adoption of Region of Provenance has a scarce significance and prominence should be given to the phenotype selection.

  8. TIME DISTRIBUTIONS OF LARGE AND SMALL SUNSPOT GROUPS OVER FOUR SOLAR CYCLES

    International Nuclear Information System (INIS)

    Kilcik, A.; Yurchyshyn, V. B.; Abramenko, V.; Goode, P. R.; Cao, W.; Ozguc, A.; Rozelot, J. P.

    2011-01-01

    Here we analyze solar activity by focusing on time variations of the number of sunspot groups (SGs) as a function of their modified Zurich class. We analyzed data for solar cycles 20-23 by using Rome (cycles 20 and 21) and Learmonth Solar Observatory (cycles 22 and 23) SG numbers. All SGs recorded during these time intervals were separated into two groups. The first group includes small SGs (A, B, C, H, and J classes by Zurich classification), and the second group consists of large SGs (D, E, F, and G classes). We then calculated small and large SG numbers from their daily mean numbers as observed on the solar disk during a given month. We report that the time variations of small and large SG numbers are asymmetric except for solar cycle 22. In general, large SG numbers appear to reach their maximum in the middle of the solar cycle (phases 0.45-0.5), while the international sunspot numbers and the small SG numbers generally peak much earlier (solar cycle phases 0.29-0.35). Moreover, the 10.7 cm solar radio flux, the facular area, and the maximum coronal mass ejection speed show better agreement with the large SG numbers than they do with the small SG numbers. Our results suggest that the large SG numbers are more likely to shed light on solar activity and its geophysical implications. Our findings may also influence our understanding of long-term variations of the total solar irradiance, which is thought to be an important factor in the Sun-Earth climate relationship.

  9. Asymptotic Behaviour of Total Generalised Variation

    KAUST Repository

    Papafitsoros, Konstantinos; Valkonen, Tuomo

    2015-01-01

    © Springer International Publishing Switzerland 2015. The recently introduced second order total generalised variation functional TGV2 β,α has been a successful regulariser for image processing purposes. Its definition involves two positive parameters α and β whose values determine the amount and the quality of the regularisation. In this paper we report on the behaviour of TGV2 β,α in the cases where the parameters α, β as well as their ratio β/α becomes very large or very small. Among others, we prove that for sufficiently symmetric two dimensional data and large ratio β/α, TGV2 β,α regularisation coincides with total variation (TV) regularization

  10. A new nonlinear blind source separation method with chaos indicators for decoupling diagnosis of hybrid failures: A marine propulsion gearbox case with a large speed variation

    International Nuclear Information System (INIS)

    Li, Zhixiong; Peng, Z

    2016-01-01

    The normal operation of propulsion gearboxes ensures the ship safety. Chaos indicators could efficiently indicate the state change of the gearboxes. However, accurate detection of gearbox hybrid faults using Chaos indicators is a challenging task and the detection under speed variation conditions is attracting considerable attentions. Literature review suggests that the gearbox vibration is a kind of nonlinear mixture of variant vibration sources and the blind source separation (BSS) is reported to be a promising technique for fault vibration analysis, but very limited work has addressed the nonlinear BSS approach for hybrid faults decoupling diagnosis. Aiming to enhance the fault detection performance of Chaos indicators, this work presents a new nonlinear BSS algorithm for gearbox hybrid faults detection under a speed variation condition. This new method appropriately introduces the kernel spectral regression (KSR) framework into the morphological component analysis (MCA). The original vibration data are projected into the reproducing kernel Hilbert space (RKHS) where the instinct nonlinear structure in the original data can be linearized by KSR. Thus the MCA is able to deal with nonlinear BSS in the KSR space. Reliable hybrid faults decoupling is then achieved by this new nonlinear MCA (NMCA). Subsequently, by calculating the Chaos indicators of the decoupled fault components and comparing them with benchmarks, the hybrid faults can be precisely identified. Two specially designed case studies were implemented to evaluate the proposed NMCA-Chaos method on hybrid gear faults decoupling diagnosis. The performance of the NMCA-Chaos was compared with state of art techniques. The analysis results show high performance of the proposed method on hybrid faults detection in a marine propulsion gearbox with large speed variations.

  11. Variation in cheliped form in two species of squat lobsters (Decapoda: Anomura from Chile

    Directory of Open Access Journals (Sweden)

    Aníbal H. Lezcano

    2015-09-01

    Full Text Available AbstractThe current study describes the variation in cheliped form of two species of squat lobsters that inhabit the continental margin off Chile: Cervimunida johni and Pleuroncodes monodon. We compared their cheliped form in the context of the reproductive strategy. The general tendency of form variation of both species is similar: chelipeds change, on average, from longer and narrower pollex with short manus to a relatively shorter and wider pollex with longer manus from small to large individuals, respectively. The degree of cheliped arching was greater in males than in females of similar carapace length, and only C. johni males showed fully arched morphology. The allometric trajectories (cheliped shape vs. carapace length were largely aligned with vectors of mean shape difference in both species. Cheliped form variation of C. johni (extended mate-guarding resembles the cheliped morphology reported for the related species Munida rugosa more than P. monodon (short mate-guarding. Our results are consistent with previous finding and suggest that the cheliped form variation (from straight and slender to a fully arched morphology is, or has been, subject to sexual selection through male-male competition for mates.

  12. Analysis of cyclic variations of liquid fuel-air mixing processes in a realistic DISI IC-engine using Large Eddy Simulation

    International Nuclear Information System (INIS)

    Goryntsev, D.; Sadiki, A.; Klein, M.; Janicka, J.

    2010-01-01

    Direct injection spark ignition (DISI) engines have a large potential to reduce emissions and specific fuel consumption. One of the most important problem in the design of DISI engines is the cycle-to-cycle variations of the flow, mixing and combustion processes. The Large Eddy Simulation (LES) based analysis is used to characterize the cycle-to-cycle fluctuations of the flow field as well as the mixture preparation in a realistic four-stroke internal combustion engine with variable charge motion system. Based on the analysis of cycle-to-cycle velocity fluctuations of in-cylinder flow, the impact of various fuel spray boundary conditions on injection processes and mixture preparation is pointed out. The joint effect of both cycle-to-cycle velocity fluctuations and variable spray boundary conditions is discussed in terms of mean and standard deviation of relative air-fuel ratio, velocity and mass fraction. Finally a qualitative analysis of the intensity of cyclic fluctuations below the spark plug is provided.

  13. Epigenetic variation, inheritance, and parent-of-origin effects of cytosine methylation in maize (Zea mays).

    Science.gov (United States)

    Lauria, Massimiliano; Piccinini, Sara; Pirona, Raul; Lund, Gertrud; Viotti, Angelo; Motto, Mario

    2014-03-01

    Pure epigenetic variation, or epigenetic variation that is independent of genetic context, may provide a mechanism for phenotypic variation in the absence of DNA mutations. To estimate the extent of pure epigenetic variation within and across generations and to identify the DNA regions targeted, a group of eight plants derived from a highly inbred line of maize (Zea mays) was analyzed by the methylation-sensitive amplified polymorphism (MSAP) technique. We found that cytosine methylation (mC) differences among individuals accounted for up to 7.4% of CCGG sites investigated by MSAP. Of the differentially methylated fragments (DMFs) identified in the S0 generation, ∼12% were meiotically inherited for at least six generations. We show that meiotically heritable mC variation was consistently generated for an average of 0.5% CCGG sites per generation and that it largely occurred somatically. We provide evidence that mC variation can be established and inherited in a parent-of-origin manner, given that the paternal lineage is more prone to both forward and reverse mC changes. The molecular characterization of selected DMFs revealed that the variation was largely determined by CG methylation changes that map within gene regions. The expression analysis of genes overlapping with DMFs did not reveal an obvious correlation between mC variation and transcription, reinforcing the idea that the primary function of gene-body methylation is not to control gene expression. Because this study focuses on epigenetic variation in field-grown plants, the data presented herein pertain to spontaneous epigenetic changes of the maize genome in a natural context.

  14. MPQS with three large primes

    NARCIS (Netherlands)

    Leyland, P.; Lenstra, A.K.; Dodson, B.; Muffett, A.; Wagstaff, S.; Fieker, C.; Kohel, D.R.

    2002-01-01

    We report the factorization of a 135-digit integer by the triple-large-prime variation of the multiple polynomial quadratic sieve. Previous workers [6][10] had suggested that using more than two large primes would be counterproductive, because of the greatly increased number of false reports from

  15. Convergence analysis of variational and non-variational multigrid algorithms for the Laplace-Beltrami operator

    KAUST Repository

    Bonito, Andrea

    2012-09-01

    We design and analyze variational and non-variational multigrid algorithms for the Laplace-Beltrami operator on a smooth and closed surface. In both cases, a uniform convergence for the V -cycle algorithm is obtained provided the surface geometry is captured well enough by the coarsest grid. The main argument hinges on a perturbation analysis from an auxiliary variational algorithm defined directly on the smooth surface. In addition, the vanishing mean value constraint is imposed on each level, thereby avoiding singular quadratic forms without adding additional computational cost. Numerical results supporting our analysis are reported. In particular, the algorithms perform well even when applied to surfaces with a large aspect ratio. © 2011 American Mathematical Society.

  16. Temporal variations of Escherichia coli concentrations in a large Midwestern river

    Science.gov (United States)

    Schilling, K.E.; Zhang, Y.-K.; Hill, D.R.; Jones, C.S.; Wolter, C.F.

    2009-01-01

    The Raccoon River used by the Des Moines Water Works to serve more than 400,000 people in central Iowa is threatened by contamination from Escherichia coli bacteria from point and nonpoint sources. The 9389 km2 watershed is highly agricultural, with 73% of the land in row crop production and widespread animal production. Results from 2155 grab samples from 1997 to 2005 for E. coli analysis were examined for temporal variations. E. coli concentrations were found to vary across years, seasons, and flow conditions, with a 9-year mean value of 1156 most probable number (MPN)/100 ml. Monthly concentrations exhibited clear seasonality with highest values in May through July. Although E. coli concentrations were higher during periods of greater discharge, the relation of log E. coli to log discharge was not particularly strong (r2 = 0.35). The variogram of E. coli concentrations showed temporal correlation within a span of 4 days suggesting that concentrations measured on 1 day may be related in time to concentrations measured up to 3 days later and beyond 4 days the concentrations vary randomly. The spectral analysis of the time series of E. coli was also carried out and was fitted well with the spectrum of an exponential covariance function. Deciphering temporal patterns and correlation of E. coli bacteria in streams may be useful for developing future monitoring strategies to track concentration patterns and loads. ?? 2008 Elsevier B.V. All rights reserved.

  17. Variations and asymmetries in regional brain surface in the genus Homo.

    Science.gov (United States)

    Balzeau, Antoine; Holloway, Ralph L; Grimaud-Hervé, Dominique

    2012-06-01

    Paleoneurology is an important field of research within human evolution studies. Variations in size and shape of an endocast help to differentiate among fossil hominin species whereas endocranial asymmetries are related to behavior and cognitive function. Here we analyse variations of the surface of the frontal, parieto-temporal and occipital lobes among different species of Homo, including 39 fossil hominins, ten fossil anatomically modern Homo sapiens and 100 endocasts of extant modern humans. We also test for the possible asymmetries of these features in a large sample of modern humans and observe individual particularities in the fossil specimens. This study contributes important new information about the brain evolution in the genus Homo. Our results show that the general pattern of surface asymmetry for the different regional brain surfaces in fossil species of Homo does not seem to be different from the pattern described in a large sample of anatomically modern H. sapiens, i.e., the right hemisphere has a larger surface than the left, as do the right frontal, the right parieto-temporal and the left occipital lobes compared with the contra-lateral side. It also appears that Asian Homo erectus specimens are discriminated from all other samples of Homo, including African and Georgian specimens that are also sometimes included in that taxon. The Asian fossils show a significantly smaller relative size of the parietal and temporal lobes. Neandertals and anatomically modern H. sapiens, who share the largest endocranial volume of all hominins, show differences when considering the relative contribution of the frontal, parieto-temporal and occipital lobes. These results illustrate an original variation in the pattern of brain organization in hominins independent of variations in total size. The globularization of the brain and the enlargement of the parietal lobes could be considered derived features observed uniquely in anatomically modern H. sapiens. Copyright

  18. Two distinct patterns of seasonal variation of airborne black carbon over Tibetan Plateau.

    Science.gov (United States)

    Wang, Mo; Xu, Baiqing; Wang, Ninglian; Cao, Junji; Tie, Xuexi; Wang, Hailong; Zhu, Chongshu; Yang, Wei

    2016-12-15

    Airborne black carbon (BC) mass concentrations were measured from November 2012 to June 2013 at Ranwu and Beiluhe, located in the southeastern and central Tibetan Plateau, respectively. Monthly mean BC concentrations show a winter (November-February) high (413.2ngm -3 ) and spring (March-June) low (139.1ngm -3 ) at Ranwu, but in contrast a winter low and spring high at Beiluhe (204.8 and 621.6ngm -3 , respectively). By examining the meteorological conditions at various scales, we found that the monthly variation of airborne BC over the southeastern Tibetan Plateau (TP) was highly influenced by regional precipitation and over the hinterland by winds. Local precipitation at both sites showed little impact on the seasonal variation of airborne BC concentrations. Potential BC source regions are identified using air mass backward trajectory analysis. At Ranwu, BC was dominated by the air masses from the northeastern India and Bangladesh in both winter and spring, whereas at Beiluhe it was largely contributed by air masses from the south slope of Himalayas in winter, and from the arid region in the north of the TP in spring. The winter and spring seasonal peak of BC in the southern TP is largely contributed by emissions from South Asia, and this seasonal variation is heavily influenced by the regional monsoon. In the northern TP, BC had high concentrations during spring and summer seasons, which is very likely associated with more efficient transport of BC over the arid regions on the north of Tibetan Plateau and in Central Asia. Airborne BC concentrations at the Ranwu sampling site showed a significant diurnal cycle with a peak shortly after sunrise followed by a decrease before noon in both winter and spring, likely shaped by local human activities and the diurnal variation of wind speed. At the Beiluhe sampling site, the diurnal variation of BC is different and less distinct. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. SSR allelic variation of rice variety Hangxiangnuo bred by space mutation

    International Nuclear Information System (INIS)

    Yang Tifeng; Liu Chuanguang; Pan Dajian; Fan Zhilan; Li Chen; Chen Jianyou; Liu Bin; Jiang Yijun; Gao Yun; Zhou Hanqin

    2011-01-01

    Hangxiangnuo, an indica fragrant glutinous rice mutant, was induced by space environment. Comparing with its wild type Nanfengnuo, the yield and blast resistance of Hangxiangnuo are improved significantly and the grain shape became slender and with fragrance. To understand the mechanisms of space mutation and identify the changes at molecular level associated with phenotypic variations, SSR allelic variation analysis were performed on Hangxiangnuo and Nanfengnuo in this study. The results showed that 45 loci were polymorphic among the 156 SSR loci tested throughout the genome, the frequency of variation was 28.85%. Among the polymorphic loci, 42 loci only showed variations in the molecular weight of the amplified bands, only on locus increased the number of amplification bands in Hangxiangnuo and two loci were differed by heterozygous loci (with two amplification bands at one locus) detected in Nanfengnuo and homozygous loci in Hangxiangnuo. It suggests that the change of some loci in mutants was due to the normal segregation and recombination of heterozygous loci of the wild type. The variation frequencies among different chromosomes were quite different, with the highest one at 50.00% detected on chromosomes 7, 8 and 12, and the lowest at 6.25% on chromosome 6. The polymorphic loci were clustered on chromosomes throughout the genome indicating that large DNA segments mutation is one of the major variation patterns induced by space environment. Some of reported QTLs involved in grain shape, yield, fragrance and blast resistance were found to be located exactly in the mutated regions. Therefore, further study is needed to confirm that these QTLs are responsible for the trait variations. (authors)

  20. Solar cycle variations in mesospheric carbon monoxide

    Science.gov (United States)

    Lee, Jae N.; Wu, Dong L.; Ruzmaikin, Alexander; Fontenla, Juan

    2018-05-01

    As an extension of Lee et al. (2013), solar cycle variation of carbon monoxide (CO) is analyzed with MLS observation, which covers more than thirteen years (2004-2017) including maximum of solar cycle 24. Being produced primarily by the carbon dioxide (CO2) photolysis in the lower thermosphere, the variations of the mesospheric CO concentration are largely driven by the solar cycle modulated ultraviolet (UV) variation. This solar signal extends down to the lower altitudes by the dynamical descent in the winter polar vortex, showing a time lag that is consistent with the average descent velocity. To characterize a global distribution of the solar impact, MLS CO is correlated with the SORCE measured total solar irradiance (TSI) and UV. As high as 0.8 in most of the polar mesosphere, the linear correlation coefficients between CO and UV/TSI are more robust than those found in the previous work. The photochemical contribution explains most (68%) of the total variance of CO while the dynamical contribution accounts for 21% of the total variance at upper mesosphere. The photochemistry driven CO anomaly signal is extended in the tropics by vertical mixing. The solar cycle signal in CO is further examined with the Whole Atmosphere Community Climate Model (WACCM) 3.5 simulation by implementing two different modeled Spectral Solar Irradiances (SSIs): SRPM 2012 and NRLSSI. The model simulations underestimate the mean CO amount and solar cycle variations of CO, by a factor of 3, compared to those obtained from MLS observation. Different inputs of the solar spectrum have small impacts on CO variation.

  1. SYSTEMATIC AND STOCHASTIC VARIATIONS IN PULSAR DISPERSION MEASURES

    International Nuclear Information System (INIS)

    Lam, M. T.; Cordes, J. M.; Chatterjee, S.; Jones, M. L.; McLaughlin, M. A.; Armstrong, J. W.

    2016-01-01

    We analyze deterministic and random temporal variations in the dispersion measure (DM) from the full three-dimensional velocities of pulsars with respect to the solar system, combined with electron-density variations over a wide range of length scales. Previous treatments have largely ignored pulsars’ changing distances while favoring interpretations involving changes in sky position from transverse motion. Linear trends in pulsar DMs observed over 5–10 year timescales may signify sizable DM gradients in the interstellar medium (ISM) sampled by the changing direction of the line of sight to the pulsar. We show that motions parallel to the line of sight can also account for linear trends, for the apparent excess of DM variance over that extrapolated from scintillation measurements, and for the apparent non-Kolmogorov scalings of DM structure functions inferred in some cases. Pulsar motions through atomic gas may produce bow-shock ionized gas that also contributes to DM variations. We discuss the possible causes of periodic or quasi-periodic changes in DM, including seasonal changes in the ionosphere, annual variations of the solar elongation angle, structure in the heliosphere and ISM boundary, and substructure in the ISM. We assess the solar cycle’s role on the amplitude of ionospheric and solar wind variations. Interstellar refraction can produce cyclic timing variations from the error in transforming arrival times to the solar system barycenter. We apply our methods to DM time series and DM gradient measurements in the literature and assess their consistency with a Kolmogorov medium. Finally, we discuss the implications of DM modeling in precision pulsar timing experiments

  2. Variations in Upper-Level Water Vapor Transport Diagnosed from Climatological Satellite Data

    Science.gov (United States)

    Lerner, Jeffrey A; Jedlovee, Gary J.; Atkinson, Robert J.

    1998-01-01

    GOES-7 VAS measurements during the Pathfinder period (1987-88) have been analysed to reveal seasonal and interannual variations in moisture transport. Long term measurements of quality winds and humidity from satellite estimates show superior benefit in diagnosing middle and upper tropospheric large scale climate variations such as ENSO events and direct circulation systems such as the Hadley Cell. A water Vapor Transport Index (WVTI) has been developed to diagnose preferred regions of strong moisture transport and to gauge the seasonal and interannual intensities detected in the GOES viewing area. Second-order variables that may be derived from GOES winds will be also discussed on the poster.

  3. Genome Variation Map: a data repository of genome variations in BIG Data Center.

    Science.gov (United States)

    Song, Shuhui; Tian, Dongmei; Li, Cuiping; Tang, Bixia; Dong, Lili; Xiao, Jingfa; Bao, Yiming; Zhao, Wenming; He, Hang; Zhang, Zhang

    2018-01-04

    The Genome Variation Map (GVM; http://bigd.big.ac.cn/gvm/) is a public data repository of genome variations. As a core resource in the BIG Data Center, Beijing Institute of Genomics, Chinese Academy of Sciences, GVM dedicates to collect, integrate and visualize genome variations for a wide range of species, accepts submissions of different types of genome variations from all over the world and provides free open access to all publicly available data in support of worldwide research activities. Unlike existing related databases, GVM features integration of a large number of genome variations for a broad diversity of species including human, cultivated plants and domesticated animals. Specifically, the current implementation of GVM not only houses a total of ∼4.9 billion variants for 19 species including chicken, dog, goat, human, poplar, rice and tomato, but also incorporates 8669 individual genotypes and 13 262 manually curated high-quality genotype-to-phenotype associations for non-human species. In addition, GVM provides friendly intuitive web interfaces for data submission, browse, search and visualization. Collectively, GVM serves as an important resource for archiving genomic variation data, helpful for better understanding population genetic diversity and deciphering complex mechanisms associated with different phenotypes. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  4. Genome Variation Map: a data repository of genome variations in BIG Data Center

    Science.gov (United States)

    Tian, Dongmei; Li, Cuiping; Tang, Bixia; Dong, Lili; Xiao, Jingfa; Bao, Yiming; Zhao, Wenming; He, Hang

    2018-01-01

    Abstract The Genome Variation Map (GVM; http://bigd.big.ac.cn/gvm/) is a public data repository of genome variations. As a core resource in the BIG Data Center, Beijing Institute of Genomics, Chinese Academy of Sciences, GVM dedicates to collect, integrate and visualize genome variations for a wide range of species, accepts submissions of different types of genome variations from all over the world and provides free open access to all publicly available data in support of worldwide research activities. Unlike existing related databases, GVM features integration of a large number of genome variations for a broad diversity of species including human, cultivated plants and domesticated animals. Specifically, the current implementation of GVM not only houses a total of ∼4.9 billion variants for 19 species including chicken, dog, goat, human, poplar, rice and tomato, but also incorporates 8669 individual genotypes and 13 262 manually curated high-quality genotype-to-phenotype associations for non-human species. In addition, GVM provides friendly intuitive web interfaces for data submission, browse, search and visualization. Collectively, GVM serves as an important resource for archiving genomic variation data, helpful for better understanding population genetic diversity and deciphering complex mechanisms associated with different phenotypes. PMID:29069473

  5. Sedimentary records of trace elements from large European lakes (Switzerland) document historic to recent freshwater pollution and climate-induced runoff variations

    Science.gov (United States)

    Thevenon, F.; Wirth, S. B.; Fujak, M.; Poté, J.; Thierry, A.; Chiaradia, M.; Girardclos, S.

    2011-12-01

    Continuous sedimentary records of anthropogenic and natural trace elements determined by ICPMS, from 5 large and deep perialpine lakes from Central Europe (Switzerland), evidence the environmental impacts of industrial fossil fuel pollution. In fact, the greatest increase in heavy metal pollution was registered at all the studied sites following the European industrial revolution of ca. AD 1800; with the highest values during the middle part of the 20th century. On a regional scale, anthropogenic heavy metal input subsequently stopped increasing thanks to remediation strategies such as the implementation of wastewater treatment plants (WWTPs). On the other hand, the discharge of industrial treated wastewaters into Vidy Bay of Lake Geneva during the second part of the 20th century involved the sedimentation of highly contaminated sediments in the area surrounding the WWTP outlet pipe discharge; less than 4 km from the main supply of drinking water of Lausanne (127'000 hab.). Microbial analyses furthermore reveal i) high increase in bacterial densities following the lake eutrophication in the 1970s, and that ii) the related sediments can be considered as a reservoir of antibiotic resistant bacteria/genes (of human origin). We finally compare instrumental hydrological data over the last century with variations of lithogenic trace elements (e.g., titanium) as registered in three large lakes (Brienz, Thun and Bienne) connected by the River Aar. This task allows to better constraining the runoff variations on a regional scale over the last decades for the the River Aar, and its possible increase under warming climate conditions in the European Alps.

  6. Patterns of DNA barcode variation in Canadian marine molluscs.

    Science.gov (United States)

    Layton, Kara K S; Martel, André L; Hebert, Paul D N

    2014-01-01

    Molluscs are the most diverse marine phylum and this high diversity has resulted in considerable taxonomic problems. Because the number of species in Canadian oceans remains uncertain, there is a need to incorporate molecular methods into species identifications. A 648 base pair segment of the cytochrome c oxidase subunit I gene has proven useful for the identification and discovery of species in many animal lineages. While the utility of DNA barcoding in molluscs has been demonstrated in other studies, this is the first effort to construct a DNA barcode registry for marine molluscs across such a large geographic area. This study examines patterns of DNA barcode variation in 227 species of Canadian marine molluscs. Intraspecific sequence divergences ranged from 0-26.4% and a barcode gap existed for most taxa. Eleven cases of relatively deep (>2%) intraspecific divergence were detected, suggesting the possible presence of overlooked species. Structural variation was detected in COI with indels found in 37 species, mostly bivalves. Some indels were present in divergent lineages, primarily in the region of the first external loop, suggesting certain areas are hotspots for change. Lastly, mean GC content varied substantially among orders (24.5%-46.5%), and showed a significant positive correlation with nearest neighbour distances. DNA barcoding is an effective tool for the identification of Canadian marine molluscs and for revealing possible cases of overlooked species. Some species with deep intraspecific divergence showed a biogeographic partition between lineages on the Atlantic, Arctic and Pacific coasts, suggesting the role of Pleistocene glaciations in the subdivision of their populations. Indels were prevalent in the barcode region of the COI gene in bivalves and gastropods. This study highlights the efficacy of DNA barcoding for providing insights into sequence variation across a broad taxonomic group on a large geographic scale.

  7. Aerodynamic Effects of High Turbulence Intensity on a Variable-Speed Power-Turbine Blade With Large Incidence and Reynolds Number Variations

    Science.gov (United States)

    Flegel, Ashlie B.; Giel, Paul W.; Welch, Gerard E.

    2014-01-01

    The effects of high inlet turbulence intensity on the aerodynamic performance of a variable speed power turbine blade are examined over large incidence and Reynolds number ranges. These results are compared to previous measurements made in a low turbulence environment. Both high and low turbulence studies were conducted in the NASA Glenn Research Center Transonic Turbine Blade Cascade Facility. The purpose of the low inlet turbulence study was to examine the transitional flow effects that are anticipated at cruise Reynolds numbers. The current study extends this to LPT-relevant turbulence levels while perhaps sacrificing transitional flow effects. Assessing the effects of turbulence at these large incidence and Reynolds number variations complements the existing database. Downstream total pressure and exit angle data were acquired for 10 incidence angles ranging from +15.8deg to -51.0deg. For each incidence angle, data were obtained at five flow conditions with the exit Reynolds number ranging from 2.12×10(exp 5) to 2.12×10(exp 6) and at a design exit Mach number of 0.72. In order to achieve the lowest Reynolds number, the exit Mach number was reduced to 0.35 due to facility constraints. The inlet turbulence intensity, Tu, was measured using a single-wire hotwire located 0.415 axial-chord upstream of the blade row. The inlet turbulence levels ranged from 8 to 15 percent for the current study. Tu measurements were also made farther upstream so that turbulence decay rates could be calculated as needed for computational inlet boundary conditions. Downstream flow field measurements were obtained using a pneumatic five-hole pitch/yaw probe located in a survey plane 7 percent axial chord aft of the blade trailing edge and covering three blade passages. Blade and endwall static pressures were acquired for each flow condition as well. The blade loading data show that the suction surface separation that was evident at many of the low Tu conditions has been eliminated. At

  8. Consequences for established design practice from geographical variation of historical rainfall data

    DEFF Research Database (Denmark)

    Mikkelsen, P.S.; Arnbjerg-Nielsen, K.; Harremoës, P.

    1997-01-01

    variation and variation due to (correlated) sampling errors. Further analyses indicate that the observed variation can be explained only partially by correlation with regional climatological variables and that a significant residual variation remains, especially for large return periods. The new perceptions...

  9. From genomic variation to personalized medicine

    DEFF Research Database (Denmark)

    Wesolowska, Agata; Schmiegelow, Kjeld

    Genomic variation is the basis of interindividual differences in observable traits and disease susceptibility. Genetic studies are the driving force of personalized medicine, as many of the differences in treatment efficacy can be attributed to our genomic background. The rapid development...... a considerable amount of the phenotype variability, hence the major difficulty of interpretation lies in the complexity of molecular interactions. This PhD thesis describes the state-of-art of the functional human variation research (Chapter 1) and introduces childhood acute lymphoblastic leukaemia (ALL...... the thesis and includes some final remarks on the perspectives of genomic variation research and personalized medicine. In summary, this thesis demonstrates the feasibility of integrative analyses of genomic variations and introduces large-scale hypothesis-driven SNP exploration studies as an emerging...

  10. Bladder filling variation during conformal radiotherapy for rectal cancer

    Science.gov (United States)

    Sithamparam, S.; Ahmad, R.; Sabarudin, A.; Othman, Z.; Ismail, M.

    2017-05-01

    Conformal radiotherapy for rectal cancer is associated with small bowel toxicity mainly diarrhea. Treating patients with a full bladder is one of the practical solutions to reduce small bowel toxicity. Previous studies on prostate and cervix cancer patients revealed that maintaining consistent bladder volume throughout radiotherapy treatment is challenging. The aim of this study was to measure bladder volume variation throughout radiotherapy treatment. This study also measured the association between bladder volume changes and diarrhea. Twenty two rectal cancer patients were recruited prospectively. Patients were planned for treatment with full bladder following departmental bladder filling protocol and the planning bladder volume was measured during CT-simulation. During radiotherapy, the bladder volume was measured weekly using cone-beam computed tomography (CBCT) and compared to planning bladder volume. Incidence and severity of diarrhea were recorded during the weekly patient review. There was a negative time trend for bladder volume throughout five weeks treatment. The mean bladder volume decreased 18 % from 123 mL (SD 54 mL) during CT-simulation to 101 mL (SD 71 mL) on the 5th week of radiotherapy, but the decrease is not statistically significant. However, there was a large variation of bladder volume within each patient during treatment. This study showed an association between changes of bladder volume and diarrhea (P = 0.045). In conclusion bladder volume reduced throughout radiotherapy treatment for conformal radiotherapy for rectal cancer and there was a large variation of bladder volume within patients.

  11. Bladder filling variation during conformal radiotherapy for rectal cancer

    International Nuclear Information System (INIS)

    Sithamparam, S; Ahmad, R; Sabarudin, A; Othman, Z; Ismail, M

    2017-01-01

    Conformal radiotherapy for rectal cancer is associated with small bowel toxicity mainly diarrhea. Treating patients with a full bladder is one of the practical solutions to reduce small bowel toxicity. Previous studies on prostate and cervix cancer patients revealed that maintaining consistent bladder volume throughout radiotherapy treatment is challenging. The aim of this study was to measure bladder volume variation throughout radiotherapy treatment. This study also measured the association between bladder volume changes and diarrhea. Twenty two rectal cancer patients were recruited prospectively. Patients were planned for treatment with full bladder following departmental bladder filling protocol and the planning bladder volume was measured during CT-simulation. During radiotherapy, the bladder volume was measured weekly using cone-beam computed tomography (CBCT) and compared to planning bladder volume. Incidence and severity of diarrhea were recorded during the weekly patient review. There was a negative time trend for bladder volume throughout five weeks treatment. The mean bladder volume decreased 18 % from 123 mL (SD 54 mL) during CT-simulation to 101 mL (SD 71 mL) on the 5th week of radiotherapy, but the decrease is not statistically significant. However, there was a large variation of bladder volume within each patient during treatment. This study showed an association between changes of bladder volume and diarrhea (P = 0.045). In conclusion bladder volume reduced throughout radiotherapy treatment for conformal radiotherapy for rectal cancer and there was a large variation of bladder volume within patients. (paper)

  12. 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; Klei, Karlijn; Fokkens, Like; Haring, Michel A.; Schranz, M. Eric; Testerink, Christa

    2016-01-01

    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

  13. Variations in pCO{sub 2} during summer in the surface water of an unproductive lake in northern Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, A.; Aaberg, J.; Jansson, M. [Dept. of Ecology and Environmental Sci ence, Umeaa Univ., 901 87 Umeaa (Sweden)]. e-mail: anders.jonsson@emg.umu.se

    2007-11-15

    Unproductive lakes are generally supersaturated with carbon dioxide (CO{sub 2}) and emit CO{sub 2} to the atmosphere continuously during ice-free periods. However, temporal variation of the partial pressure of CO{sub 2} (pCO{sub 2}) and thus of CO{sub 2} evasion to atmosphere is poorly documented. We therefore carried out temporally high-resolution (every 6 h) measurements of the pCO{sub 2} using an automated logger system in the surface water of a subarctic, unproductive, lake in the birch forest belt. The study period was June-September 2004. We found that the pCO{sub 2} showed large seasonal variation, but low daily variation. The seasonal variation was likely mainly caused by variations in input and mineralization of allochthonous organic matter. Stratification depth probably also influenced pCO{sub 2} of the surface water by controlling the volume in which mineralization of dissolved organic carbon (DOC) occurred. In lakes, with large variations in pCO{sub 2}, as in our study lake a high (weekly) sampling intensity is recommended for obtaining accurate estimates of the evasion of CO{sub 2}.

  14. Factors influencing variation in dentist service rates.

    Science.gov (United States)

    Grembowski, D; Milgrom, P; Fiset, L

    1990-01-01

    In the previous article, we calculated dentist service rates for 200 general dentists based on a homogeneous, well-educated, upper-middle-class population of patients. Wide variations in the rates were detected. In this analysis, factors influencing variation in the rates were identified. Variation in rates for categories of dental services was explained by practice characteristics, patient exposure to fluoridated water supplies, and non-price competition in the dental market. Rates were greatest in large, busy practices in markets with high fees. Older practices consistently had lower rates across services. As a whole, these variables explained between 5 and 30 percent of the variation in the rates.

  15. PHOTOSPHERIC VARIATIONS OF THE SUPERGIANT γ Cyg

    International Nuclear Information System (INIS)

    Gray, David F.

    2010-01-01

    New high-resolution spectroscopic observations of the supergiant γ Cyg (F8 Iab) taken between 2000 and 2008 consistently show strongly reversed-C-shaped bisectors for all unblended spectral lines. Small-amplitude variations in radial velocity and line shapes occur in an irregular manner with time scales ∼100 days and longer. The radial velocities occasionally show changes as large as 2 km s -1 , but much smaller changes are going on continuously. Differential line bisectors show shape changes and Doppler displacement characteristic of radial expansion and contraction. These might arise from non-periodic radial pulsation-like motions or from the appearance of giant convection cells that occupy most of the visible hemisphere of the star. Line-depth ratios are correlated with the line shifts on a seasonal basis and indicate temperature changes ranging up to ∼15 K, with larger temperature occurring during times of most rapid contraction.

  16. Four loci explain 83% of size variation in the horse.

    Directory of Open Access Journals (Sweden)

    Shokouh Makvandi-Nejad

    Full Text Available Horse body size varies greatly due to intense selection within each breed. American Miniatures are less than one meter tall at the withers while Shires and Percherons can exceed two meters. The genetic basis for this variation is not known. We hypothesize that the breed population structure of the horse should simplify efforts to identify genes controlling size. In support of this, here we show with genome-wide association scans (GWAS that genetic variation at just four loci can explain the great majority of horse size variation. Unlike humans, which are naturally reproducing and possess many genetic variants with weak effects on size, we show that horses, like other domestic mammals, carry just a small number of size loci with alleles of large effect. Furthermore, three of our horse size loci contain the LCORL, HMGA2 and ZFAT genes that have previously been found to control human height. The LCORL/NCAPG locus is also implicated in cattle growth and HMGA2 is associated with dog size. Extreme size diversification is a hallmark of domestication. Our results in the horse, complemented by the prior work in cattle and dog, serve to pinpoint those very few genes that have played major roles in the rapid evolution of size during domestication.

  17. The variational spiked oscillator

    International Nuclear Information System (INIS)

    Aguilera-Navarro, V.C.; Ullah, N.

    1992-08-01

    A variational analysis of the spiked harmonic oscillator Hamiltonian -d 2 / d x 2 + x 2 + δ/ x 5/2 , δ > 0, is reported in this work. A trial function satisfying Dirichlet boundary conditions is suggested. The results are excellent for a large range of values of the coupling parameter. (author)

  18. Male density affects large-male advantage in the golden silk spider, Nephila clavipes

    OpenAIRE

    Clare C. Rittschof

    2010-01-01

    Across a variety of animal taxa, the outcome of male--male contests depends on male body size; winners are usually the larger males or the males with bigger weapons. However, high male density can either increase or reverse large-male advantage because density changes the frequency and intensity of male--male interactions. In the golden orb-web spider Nephila clavipes, large males have a competitive advantage in male--male contests. However, this species shows more than 2-fold variation in ma...

  19. The vascular disrupting agent ZD6126 shows increased antitumor efficacy and enhanced radiation response in large, advanced tumors

    International Nuclear Information System (INIS)

    Siemann, Dietmar W.; Rojiani, Amyn M.

    2005-01-01

    Purpose: ZD6126 is a vascular-targeting agent that induces selective effects on the morphology of proliferating and immature endothelial cells by disrupting the tubulin cytoskeleton. The efficacy of ZD6126 was investigated in large vs. small tumors in a variety of animal models. Methods and Materials: Three rodent tumor models (KHT, SCCVII, RIF-1) and three human tumor xenografts (Caki-1, KSY-1, SKBR3) were used. Mice bearing leg tumors ranging in size from 0.1-2.0 g were injected intraperitoneally with a single 150 mg/kg dose of ZD6126. The response was assessed by morphologic and morphometric means as well as an in vivo to in vitro clonogenic cell survival assay. To examine the impact of tumor size on the extent of enhancement of radiation efficacy by ZD6126, KHT sarcomas of three different sizes were irradiated locally with a range of radiation doses, and cell survival was determined. Results: All rodent tumors and human tumor xenografts evaluated showed a strong correlation between increasing tumor size and treatment effect as determined by clonogenic cell survival. Detailed evaluation of KHT sarcomas treated with ZD6126 showed a reduction in patent tumor blood vessels that was ∼20% in small ( 90% in large (>1.0 g) tumors. Histologic assessment revealed that the extent of tumor necrosis after ZD6126 treatment, although minimal in small KHT sarcomas, became more extensive with increasing tumor size. Clonogenic cell survival after ZD6126 exposure showed a decrease in tumor surviving fraction from approximately 3 x 10 -1 to 1 x 10 -4 with increasing tumor size. When combined with radiotherapy, ZD6126 treatment resulted in little enhancement of the antitumor effect of radiation in small (<0.3 g) tumors but marked increases in cell kill in tumors larger than 1.0 g. Conclusions: Because bulky neoplastic disease is typically the most difficult to manage, the present findings provide further support for the continued development of vascular disrupting agents such as

  20. Variational principles

    CERN Document Server

    Moiseiwitsch, B L

    2004-01-01

    This graduate-level text's primary objective is to demonstrate the expression of the equations of the various branches of mathematical physics in the succinct and elegant form of variational principles (and thereby illuminate their interrelationship). Its related intentions are to show how variational principles may be employed to determine the discrete eigenvalues for stationary state problems and to illustrate how to find the values of quantities (such as the phase shifts) that arise in the theory of scattering. Chapter-by-chapter treatment consists of analytical dynamics; optics, wave mecha

  1. Variations in the gender composition of immigrant populations: how they matter.

    Science.gov (United States)

    Donato, Katharine M; Alexander, Joseph T; Gabaccia, Donna R; Leinonen, Johanna

    2011-01-01

    This paper estimates and interprets empirical shifts in the gender composition of immigrants to add to scholarship about the gendering of international migrations over time. We map shifts in gender ratios using micro-level data that permit us to create age-standardized estimates among adult foreign born stock living in the United States since 1850 and in 26 other nations worldwide since 1960. We examine regional and national variations in these shifts, and ask whether and how the gendered composition of foreigners from diverse origins in the United States – the nation that has received the largest populations of migrants for over a century – differs from other nations that receive large numbers of immigrants. We also examine recent variations in gender ratios among immigrants living in six regional destination countries. Results show substantial variation in the gender composition of foreign-born populations, and they offer a starting point for examining causes and consequences in future research.

  2. Is there much variation in variation? Revisiting statistics of small area variation in health services research

    Directory of Open Access Journals (Sweden)

    Ibáñez Berta

    2009-04-01

    Full Text Available Abstract Background The importance of Small Area Variation Analysis for policy-making contrasts with the scarcity of work on the validity of the statistics used in these studies. Our study aims at 1 determining whether variation in utilization rates between health areas is higher than would be expected by chance, 2 estimating the statistical power of the variation statistics; and 3 evaluating the ability of different statistics to compare the variability among different procedures regardless of their rates. Methods Parametric bootstrap techniques were used to derive the empirical distribution for each statistic under the hypothesis of homogeneity across areas. Non-parametric procedures were used to analyze the empirical distribution for the observed statistics and compare the results in six situations (low/medium/high utilization rates and low/high variability. A small scale simulation study was conducted to assess the capacity of each statistic to discriminate between different scenarios with different degrees of variation. Results Bootstrap techniques proved to be good at quantifying the difference between the null hypothesis and the variation observed in each situation, and to construct reliable tests and confidence intervals for each of the variation statistics analyzed. Although the good performance of Systematic Component of Variation (SCV, Empirical Bayes (EB statistic shows better behaviour under the null hypothesis, it is able to detect variability if present, it is not influenced by the procedure rate and it is best able to discriminate between different degrees of heterogeneity. Conclusion The EB statistics seems to be a good alternative to more conventional statistics used in small-area variation analysis in health service research because of its robustness.

  3. Accommodating variation: dialects, idiolects, and speech processing.

    Science.gov (United States)

    Kraljic, Tanya; Brennan, Susan E; Samuel, Arthur G

    2008-04-01

    Listeners are faced with enormous variation in pronunciation, yet they rarely have difficulty understanding speech. Although much research has been devoted to figuring out how listeners deal with variability, virtually none (outside of sociolinguistics) has focused on the source of the variation itself. The current experiments explore whether different kinds of variation lead to different cognitive and behavioral adjustments. Specifically, we compare adjustments to the same acoustic consequence when it is due to context-independent variation (resulting from articulatory properties unique to a speaker) versus context-conditioned variation (resulting from common articulatory properties of speakers who share a dialect). The contrasting results for these two cases show that the source of a particular acoustic-phonetic variation affects how that variation is handled by the perceptual system. We also show that changes in perceptual representations do not necessarily lead to changes in production.

  4. Ultra Deep Sequencing of a Baculovirus Population Reveals Widespread Genomic Variations

    Directory of Open Access Journals (Sweden)

    Aurélien Chateigner

    2015-07-01

    Full Text Available Viruses rely on widespread genetic variation and large population size for adaptation. Large DNA virus populations are thought to harbor little variation though natural populations may be polymorphic. To measure the genetic variation present in a dsDNA virus population, we deep sequenced a natural strain of the baculovirus Autographa californica multiple nucleopolyhedrovirus. With 124,221X average genome coverage of our 133,926 bp long consensus, we could detect low frequency mutations (0.025%. K-means clustering was used to classify the mutations in four categories according to their frequency in the population. We found 60 high frequency non-synonymous mutations under balancing selection distributed in all functional classes. These mutants could alter viral adaptation dynamics, either through competitive or synergistic processes. Lastly, we developed a technique for the delimitation of large deletions in next generation sequencing data. We found that large deletions occur along the entire viral genome, with hotspots located in homologous repeat regions (hrs. Present in 25.4% of the genomes, these deletion mutants presumably require functional complementation to complete their infection cycle. They might thus have a large impact on the fitness of the baculovirus population. Altogether, we found a wide breadth of genomic variation in the baculovirus population, suggesting it has high adaptive potential.

  5. Clostridium tyrobutyricum strains show wide variation in growth at different NaCl, pH, and temperature conditions.

    Science.gov (United States)

    Ruusunen, Marjo; Surakka, Anu; Korkeala, Hannu; Lindström, Miia

    2012-10-01

    Outgrowth from Clostridium tyrobutyricum spores in milk can lead to butyric acid fermentation in cheeses, causing spoilage and economical loss to the dairy industry. The aim of this study was to investigate the growth of 10 C. tyrobutyricum strains at different NaCl, pH, and temperature conditions. Up to 7.5-fold differences among the maximum growth rates of different strains in the presence of 2.0% NaCl were observed. Five of 10 strains were able to grow in the presence of 3.0% NaCl, while a NaCl concentration of 3.5% was completely inhibitory to all strains. Seven of 10 strains were able to grow at pH 5.0, and up to 4- and 12.5-fold differences were observed among the maximum growth rates of different strains at pH 5.5 and 7.5, respectively. The maximum growth temperatures varied from 40.2 to 43.3°C. The temperature of 10°C inhibited the growth of all strains, while 8 of 10 strains grew at 12 and 15°C. Despite showing no growth, all strains were able to survive at 10°C. In conclusion, wide variation was observed among different C. tyrobutyricum strains in their ability to grow at different stressful conditions. Understanding the physiological diversity among the strains is important when designing food control measures and predictive models for the growth of spoilage organisms in cheese.

  6. Temporal variations of radon concentration in the saturated soil of Alpine grassland: The role of groundwater flow

    International Nuclear Information System (INIS)

    Perrier, Frederic; Richon, Patrick; Sabroux, Jean-Christophe

    2009-01-01

    Radon concentration has been monitored from 1995 to 1999 in the soil of the Sur-Fretes ridge (French Alps), covered with snow from November to April. Measurements were performed at 70 cm depth, with a sampling time of 1 h, at two points: the summit of the ridge, at an altitude of 1792 m, and the bottom of the ridge, at an altitude of 1590 m. On the summit, radon concentration shows a moderate seasonal variation, with a high value from October to April (winter), and a low value from May to September (summer). At the bottom of the ridge, a large and opposite seasonal variation is observed, with a low value in winter and a high value in summer. Fluctuations of the radon concentration seem to be associated with temperature variations, an effect which is largely delusory. Indeed, these variations are actually due to water infiltration. A simplified mixing model is used to show that, at the summit of the ridge, two effects compete in the radon response: a slow infiltration response, rich in radon, with a typical time scale of days, and a fast infiltration of radon-poor rainwater. At the bottom of the ridge, similarly, two groundwater contributions compete: one slow infiltration response, similar to the response seen at the summit, and an additional slower response, with a typical time scale of about a month. This second slower response can be interpreted as the aquifer discharge in response to snow melt. This study shows that, while caution is necessary to properly interpret the various effects, the temporal variations of the radon concentration in soil can be understood reasonably well, and appear to be a sensitive tool to study the subtle interplay of near surface transfer processes of groundwater with different transit times

  7. Temporal variations of radon concentration in the saturated soil of Alpine grassland: the role of groundwater flow.

    Science.gov (United States)

    Perrier, Frédéric; Richon, Patrick; Sabroux, Jean-Christophe

    2009-03-15

    Radon concentration has been monitored from 1995 to 1999 in the soil of the Sur-Frêtes ridge (French Alps), covered with snow from November to April. Measurements were performed at 70 cm depth, with a sampling time of 1 h, at two points: the summit of the ridge, at an altitude of 1792 m, and the bottom of the ridge, at an altitude of 1590 m. On the summit, radon concentration shows a moderate seasonal variation, with a high value from October to April (winter), and a low value from May to September (summer). At the bottom of the ridge, a large and opposite seasonal variation is observed, with a low value in winter and a high value in summer. Fluctuations of the radon concentration seem to be associated with temperature variations, an effect which is largely delusory. Indeed, these variations are actually due to water infiltration. A simplified mixing model is used to show that, at the summit of the ridge, two effects compete in the radon response: a slow infiltration response, rich in radon, with a typical time scale of days, and a fast infiltration of radon-poor rainwater. At the bottom of the ridge, similarly, two groundwater contributions compete: one slow infiltration response, similar to the response seen at the summit, and an additional slower response, with a typical time scale of about a month. This second slower response can be interpreted as the aquifer discharge in response to snow melt. This study shows that, while caution is necessary to properly interpret the various effects, the temporal variations of the radon concentration in soil can be understood reasonably well, and appear to be a sensitive tool to study the subtle interplay of near surface transfer processes of groundwater with different transit times.

  8. Seasonal and Diurnal Variations of Atmospheric Non-Methane Hydrocarbons in Guangzhou, China

    Directory of Open Access Journals (Sweden)

    Longfeng Li

    2012-05-01

    Full Text Available In recent decades, high ambient ozone concentrations have become one of the major regional air quality issues in the Pearl River Delta (PRD region. Non-methane hydrocarbons (NMHCs, as key precursors of ozone, were found to be the limiting factor in photochemical ozone formation for large areas in the PRD. For source apportioning of NMHCs as well as ozone pollution control strategies, it is necessary to obtain typical seasonal and diurnal patterns of NMHCs with a large pool of field data. To date, few studies have focused on seasonal and diurnal variations of NMHCs in urban areas of Guangzhou. This study explored the seasonal variations of most hydrocarbons concentrations with autumn maximum and spring minimum in Guangzhou. The diurnal variations of most anthropogenic NMHCs typically showed two-peak pattern with one at 8:00 in the morning and another at 20:00 in the evening, both corresponding to traffic rush hours in Guangzhou, whereas isoprene displayed a different bimodal diurnal curve. Propene, ethene, m, p-xylene and toluene were the four largest contributors to ozone formation in Guangzhou, based on the evaluation of individual NMHCs’ photochemical reactivity. Therefore, an effective strategy for controlling ozone pollution may be achieved by the reduction of vehicle emissions in Guangzhou.

  9. Geographic Variation in Advertisement Calls in a Tree Frog Species: Gene Flow and Selection Hypotheses

    Science.gov (United States)

    Jang, Yikweon; Hahm, Eun Hye; Lee, Hyun-Jung; Park, Soyeon; Won, Yong-Jin; Choe, Jae C.

    2011-01-01

    Background In a species with a large distribution relative to its dispersal capacity, geographic variation in traits may be explained by gene flow, selection, or the combined effects of both. Studies of genetic diversity using neutral molecular markers show that patterns of isolation by distance (IBD) or barrier effect may be evident for geographic variation at the molecular level in amphibian species. However, selective factors such as habitat, predator, or interspecific interactions may be critical for geographic variation in sexual traits. We studied geographic variation in advertisement calls in the tree frog Hyla japonica to understand patterns of variation in these traits across Korea and provide clues about the underlying forces for variation. Methodology We recorded calls of H. japonica in three breeding seasons from 17 localities including localities in remote Jeju Island. Call characters analyzed were note repetition rate (NRR), note duration (ND), and dominant frequency (DF), along with snout-to-vent length. Results The findings of a barrier effect on DF and a longitudinal variation in NRR seemed to suggest that an open sea between the mainland and Jeju Island and mountain ranges dominated by the north-south Taebaek Mountains were related to geographic variation in call characters. Furthermore, there was a pattern of IBD in mitochondrial DNA sequences. However, no comparable pattern of IBD was found between geographic distance and call characters. We also failed to detect any effects of habitat or interspecific interaction on call characters. Conclusions Geographic variations in call characters as well as mitochondrial DNA sequences were largely stratified by geographic factors such as distance and barriers in Korean populations of H. japoinca. Although we did not detect effects of habitat or interspecific interaction, some other selective factors such as sexual selection might still be operating on call characters in conjunction with restricted gene

  10. A stochastic large deformation model for computational anatomy

    DEFF Research Database (Denmark)

    Arnaudon, Alexis; Holm, Darryl D.; Pai, Akshay Sadananda Uppinakudru

    2017-01-01

    In the study of shapes of human organs using computational anatomy, variations are found to arise from inter-subject anatomical differences, disease-specific effects, and measurement noise. This paper introduces a stochastic model for incorporating random variations into the Large Deformation...

  11. Seasonal variation in the Dutch bovine raw milk composition

    NARCIS (Netherlands)

    Heck, J.M.L.; Valenberg, van H.J.F.; Dijkstra, J.; Hooijdonk, van A.C.M.

    2009-01-01

    In this study, we determined the detailed composition of and seasonal variation in Dutch dairy milk. Raw milk samples representative of the complete Dutch milk supply were collected weekly from February 2005 until February 2006. Large seasonal variation exists in the concentrations of the main

  12. Schwinger variational calculation of ionization of hydrogen atoms for ...

    Indian Academy of Sciences (India)

    Schwinger variational calculation of ionization of hydrogen atoms for large momentum transfers. K CHAKRABARTI. Department of Mathematics, Scottish Church College, 1 & 3 Urquhart Square,. Kolkata 700 006, India. MS received 7 July 2001; revised 10 October 2001. Abstract. Schwinger variational principle is used here ...

  13. Harmonically excited orbital variations

    International Nuclear Information System (INIS)

    Morgan, T.

    1985-01-01

    Rephrasing the equations of motion for orbital maneuvers in terms of Lagrangian generalized coordinates instead of Newtonian rectangular cartesian coordinates can make certain harmonic terms in the orbital angular momentum vector more readily apparent. In this formulation the equations of motion adopt the form of a damped harmonic oscillator when torques are applied to the orbit in a variationally prescribed manner. The frequencies of the oscillator equation are in some ways unexpected but can nonetheless be exploited through resonant forcing functions to achieve large secular variations in the orbital elements. Two cases are discussed using a circular orbit as the control case: (1) large changes in orbital inclination achieved by harmonic excitation rather than one impulsive velocity change, and (2) periodic and secular changes to the longitude of the ascending node using both stable and unstable excitation strategies. The implications of these equations are also discussed for both artificial satellites and natural satellites. For the former, two utilitarian orbits are suggested, each exploiting a form of harmonic excitation. 5 refs

  14. Within and between population variation in epidermal club cell investment in a freshwater prey fish: a cautionary tale for evolutionary ecologists.

    Directory of Open Access Journals (Sweden)

    Aditya K Manek

    Full Text Available Many prey fishes possess large club cells in their epidermis. The role of these cells has garnered considerable attention from evolutionary ecologists. These cells likely form part of the innate immune system of fishes, however, they also have an alarm function, releasing chemical cues that serve to warn nearby conspecifics of danger. Experiments aimed at understanding the selection pressures leading to the evolution of these cells have been hampered by a surprisingly large intraspecific variation in epidermal club cell (ECC investment. The goal of our current work was to explore the magnitude and nature of this variation in ECC investment. In a field survey, we documented large differences in ECC investment both within and between several populations of minnows. We then tested whether we could experimentally reduce variation in mean ECC number by raising fish under standard laboratory conditions for 4 weeks. Fish from different populations responded very differently to being held under standard laboratory conditions; some populations showed an increase in ECC investment while others remained unchanged. More importantly, we found some evidence that we could reduce within population variation in ECC investment through time, but could not reduce among-population variation in mean ECC investment. Given the large variation we observed in wild fish and our limited ability to converge mean cell number by holding the fish under standard conditions, we caution that future studies may be hard pressed to find subtle effects of various experimental manipulations; this will make elucidating the selection pressures leading to the evolution of the cells challenging.

  15. Variation across mitochondrial gene trees provides evidence for systematic error: How much gene tree variation is biological?

    Science.gov (United States)

    Richards, Emilie J; Brown, Jeremy M; Barley, Anthony J; Chong, Rebecca A; Thomson, Robert C

    2018-02-19

    The use of large genomic datasets in phylogenetics has highlighted extensive topological variation across genes. Much of this discordance is assumed to result from biological processes. However, variation among gene trees can also be a consequence of systematic error driven by poor model fit, and the relative importance of biological versus methodological factors in explaining gene tree variation is a major unresolved question. Using mitochondrial genomes to control for biological causes of gene tree variation, we estimate the extent of gene tree discordance driven by systematic error and employ posterior prediction to highlight the role of model fit in producing this discordance. We find that the amount of discordance among mitochondrial gene trees is similar to the amount of discordance found in other studies that assume only biological causes of variation. This similarity suggests that the role of systematic error in generating gene tree variation is underappreciated and critical evaluation of fit between assumed models and the data used for inference is important for the resolution of unresolved phylogenetic questions.

  16. Composition variations of low energy heavy ions during large solar energetic particle events

    Energy Technology Data Exchange (ETDEWEB)

    Ho, George C., E-mail: George.Ho@jhuapl.edu; Mason, Glenn M., E-mail: Glenn.Mason@jhuapl.edu [Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723 (United States)

    2016-03-25

    The time-intensity profile of large solar energetic particle (SEP) event is well organized by solar longitude as observed at Earth orbit. This is mostly due to different magnetic connection to the shock that is associated with large SEP event propagates from the Sun to the heliosphere. Earlier studies have shown event averaged heavy ion abundance ratios can also vary as a function of solar longitude. It was found that the Fe/O ratio for high energy particle (>10 MeV/nucleon) is higher for those western magnetically well connected events compare to the eastern events as observed at L1 by the Advanced Composition Explorer (ACE) spacecraft. In this paper, we examined the low energy (∼1 MeV/nucleon) heavy ions in 110 isolated SEP events from 2009 to the end of 2014. In addition, the optical and radio signatures for all of our events are identified and when data are available we also located the associated coronal mass ejection (CME) data. Our survey shows a higher Fe/O ratio at events in the well-connected region, while there are no corrections between the event averaged elemental composition with the associated coronal mass ejection speed. This is inconsistent with the higher energy results, but inline with other recent low-energy measurements.

  17. Seasonal variation of radon concentrations in UK homes

    International Nuclear Information System (INIS)

    Miles, J C H; Howarth, C B; Hunter, N

    2012-01-01

    The patterns of seasonal variation of radon concentrations were measured in 91 homes in five regions of the UK over a period of two years. The results showed that there was no significant difference between the regions in the pattern or magnitude of seasonal variation in radon concentrations. The arithmetic mean variation was found to be close to that found previously in the UK national survey. Differences in the pattern between the two years of the study were not significant. Two-thirds of homes in the study followed the expected pattern of high radon in the winter and low radon in the summer. Most of the rest showed little seasonal variation, and a few showed a reversed seasonal pattern. The study does not provide any clear evidence for the recorded house characteristics having an effect on the seasonal variation in radon concentrations in UK homes, though the statistical power for determining such effects is limited in this study. The magnitude of the seasonal variation varied widely between homes. Analysis of the individual results from the homes showed that because of the wide variation in the amount of seasonal variation, applying seasonal correction factors to the results of three-month measurements can yield only relatively small improvements in the accuracy of estimates of annual mean concentrations.

  18. Sources of measurement variation in blood pressure in large-scale epidemiological surveys with follow-up

    DEFF Research Database (Denmark)

    Andersen, Ulla Overgaard; Henriksen, Jens H; Jensen, Gorm

    2002-01-01

    The Copenhagen City Heart Study (CCHS) is a longitudinal epidemiological study of 19698 subjects followed up since 1976. Variation in blood pressure (BP) measurement in the first three CCHS surveys is evaluated by assessing two components, systematic variation and random variation [daytime...... min rest, with the cuff around the non-dominating arm, in accordance with recommended guidelines. The participation rate fell from 74% in survey 1 to 63% in survey 3. Significant non-response bias with respect to BP values was not found. No daytime variability was noted either in systolic (SBP...... and plasma cholesterol. SBP was 5-10 mmHg higher in diabetics (p = 0.000-0.04) than in age- and sex-matched non-diabetics. DBP did not differ between the two groups. Smokers from the age of 50 years had a 2-4 mmHg lower SBP (p = 0.000-0.01) and 1-3 mmHg lower DBP (p = 0.000-0.005) than had non...

  19. The African Genome Variation Project shapes medical genetics in Africa

    Science.gov (United States)

    Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O.; Choudhury, Ananyo; Ritchie, Graham R. S.; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N.; Young, Elizabeth H.; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P.; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A.; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S.

    2015-01-01

    Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa.

  20. The African Genome Variation Project shapes medical genetics in Africa.

    Science.gov (United States)

    Gurdasani, Deepti; Carstensen, Tommy; Tekola-Ayele, Fasil; Pagani, Luca; Tachmazidou, Ioanna; Hatzikotoulas, Konstantinos; Karthikeyan, Savita; Iles, Louise; Pollard, Martin O; Choudhury, Ananyo; Ritchie, Graham R S; Xue, Yali; Asimit, Jennifer; Nsubuga, Rebecca N; Young, Elizabeth H; Pomilla, Cristina; Kivinen, Katja; Rockett, Kirk; Kamali, Anatoli; Doumatey, Ayo P; Asiki, Gershim; Seeley, Janet; Sisay-Joof, Fatoumatta; Jallow, Muminatou; Tollman, Stephen; Mekonnen, Ephrem; Ekong, Rosemary; Oljira, Tamiru; Bradman, Neil; Bojang, Kalifa; Ramsay, Michele; Adeyemo, Adebowale; Bekele, Endashaw; Motala, Ayesha; Norris, Shane A; Pirie, Fraser; Kaleebu, Pontiano; Kwiatkowski, Dominic; Tyler-Smith, Chris; Rotimi, Charles; Zeggini, Eleftheria; Sandhu, Manjinder S

    2015-01-15

    Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. The African Genome Variation Project provides a resource with which to design, implement and interpret genomic studies in sub-Saharan Africa and worldwide. The African Genome Variation Project represents dense genotypes from 1,481 individuals and whole-genome sequences from 320 individuals across sub-Saharan Africa. Using this resource, we find novel evidence of complex, regionally distinct hunter-gatherer and Eurasian admixture across sub-Saharan Africa. We identify new loci under selection, including loci related to malaria susceptibility and hypertension. We show that modern imputation panels (sets of reference genotypes from which unobserved or missing genotypes in study sets can be inferred) can identify association signals at highly differentiated loci across populations in sub-Saharan Africa. Using whole-genome sequencing, we demonstrate further improvements in imputation accuracy, strengthening the case for large-scale sequencing efforts of diverse African haplotypes. Finally, we present an efficient genotype array design capturing common genetic variation in Africa.

  1. On the analysis of line profile variations: A statistical approach

    International Nuclear Information System (INIS)

    McCandliss, S.R.

    1988-01-01

    This study is concerned with the empirical characterization of the line profile variations (LPV), which occur in many of and Wolf-Rayet stars. The goal of the analysis is to gain insight into the physical mechanisms producing the variations. The analytic approach uses a statistical method to quantify the significance of the LPV and to identify those regions in the line profile which are undergoing statistically significant variations. Line positions and flux variations are then measured and subject to temporal and correlative analysis. Previous studies of LPV have for the most part been restricted to observations of a single line. Important information concerning the range and amplitude of the physical mechanisms involved can be obtained by simultaneously observing spectral features formed over a range of depths in the extended mass losing atmospheres of massive, luminous stars. Time series of a Wolf-Rayet and two of stars with nearly complete spectral coverage from 3940 angstrom to 6610 angstrom and with spectral resolution of R = 10,000 are analyzed here. These three stars exhibit a wide range of both spectral and temporal line profile variations. The HeII Pickering lines of HD 191765 show a monotonic increase in the peak rms variation amplitude with lines formed at progressively larger radii in the Wolf-Rayet star wind. Two times scales of variation have been identified in this star: a less than one day variation associated with small scale flickering in the peaks of the line profiles and a greater than one day variation associated with large scale asymmetric changes in the overall line profile shapes. However, no convincing period phenomena are evident at those periods which are well sampled in this time series

  2. A comparison of vowel normalization procedures for language variation research

    Science.gov (United States)

    Adank, Patti; Smits, Roel; van Hout, Roeland

    2004-11-01

    An evaluation of vowel normalization procedures for the purpose of studying language variation is presented. The procedures were compared on how effectively they (a) preserve phonemic information, (b) preserve information about the talker's regional background (or sociolinguistic information), and (c) minimize anatomical/physiological variation in acoustic representations of vowels. Recordings were made for 80 female talkers and 80 male talkers of Dutch. These talkers were stratified according to their gender and regional background. The normalization procedures were applied to measurements of the fundamental frequency and the first three formant frequencies for a large set of vowel tokens. The normalization procedures were evaluated through statistical pattern analysis. The results show that normalization procedures that use information across multiple vowels (``vowel-extrinsic'' information) to normalize a single vowel token performed better than those that include only information contained in the vowel token itself (``vowel-intrinsic'' information). Furthermore, the results show that normalization procedures that operate on individual formants performed better than those that use information across multiple formants (e.g., ``formant-extrinsic'' F2-F1). .

  3. Variational transition state theory

    International Nuclear Information System (INIS)

    Truhlar, D.G.

    1986-01-01

    This project is concerned with the development and applications of generalized transition state theory and multidimensional tunneling approximations to chemical reaction rates. They have developed and implemented several practical versions of variational transition state theory (VTST), namely canonical variational theory (CVT), improved canonical variational theory (ICVT), and microcanonical variational theory (μVT). They have also developed and implemented several accurate multidimensional semiclassical tunneling approximations, the most accurate of which are the small-curvature semiclassical adiabatic (SCSA), large-curvature version-3 (LC3), and least-action (LA) approximations. They have applied the methods to thermal rate constants, using transmission coefficients based on ground-state tunneling, and they have also presented and applied adiabatic and diabatic extensions to calculated rate constants for vibrationally excited reactants. Their general goal is to develop accurate methods for calculating chemical reaction rate constants that remain practical even for reasonably complicated molecules. The approximations mentioned above yield rate constants for systems whose potential energy surface is known or assumed. Thus a second, equally important aspect of their work is the determination or modeling, semi-empirically and/or from electronic structure calculations, of potential energy surfaces

  4. Two distinct patterns of seasonal variation of airborne black carbon over Tibetan Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mo; Xu, Baiqing; Wang, Ninglian; Cao, Junji; Tie, Xuexi; Wang, Hailong; Zhu, Chongshu; Yang, Wei

    2016-12-01

    Airborne black carbon (BC) mass concentrations were measured from November 2012 to June 2013 at Ranwu and Beiluhe, located in the southeastern and central Tibetan Plateau, respectively. Monthly mean BC concentrations showawinter (November–February) high (413.2 ng m$-$3) and spring (March–June) low(139.1 ng m$-$3) at Ranwu, but in contrast awinter lowand spring high at Beiluhe (204.8 and 621.6 ng m$-$3, respectively). By examining the meteorological conditions at various scales, we found that themonthly variation of airborne BC over the southeastern Tibetan Plateau (TP) was highly influenced by regional precipitation and over the hinterland by winds. Local precipitation at both sites showed little impact on the seasonal variation of airborne BC concentrations. Potential BC source regions are identified using air mass backward trajectory analysis. At Ranwu, BC was dominated by the air masses from the northeastern India and Bangladesh in both winter and spring, whereas at Beiluhe it was largely contributed by air masses from the south slope of Himalayas in winter, and from the arid region in the north of the TP in spring. Thewinter and spring seasonal peak of BC in the southern TP is largely contributed by emissions from South Asia, and this seasonal variation is heavily influenced by the regional monsoon. In the northern TP, BC had high concentrations during spring and summer seasons, which is very likely associated with more efficient transport of BC over the arid regions on the north of Tibetan Plateau and in Central Asia. Airborne BC concentrations at the Ranwusampling site showed a significant diurnal cyclewith a peak shortly after sunrise followed by a decrease before noon in both winter and spring, likely shaped by local human activities and the diurnal variation of wind speed. At the Beiluhe sampling site, the diurnal variation of BC is different and less distinct.

  5. Variation in human recombination rates and its genetic determinants.

    Directory of Open Access Journals (Sweden)

    Adi Fledel-Alon

    Full Text Available Despite the fundamental role of crossing-over in the pairing and segregation of chromosomes during human meiosis, the rates and placements of events vary markedly among individuals. Characterizing this variation and identifying its determinants are essential steps in our understanding of the human recombination process and its evolution.Using three large sets of European-American pedigrees, we examined variation in five recombination phenotypes that capture distinct aspects of crossing-over patterns. We found that the mean recombination rate in males and females and the historical hotspot usage are significantly heritable and are uncorrelated with one another. We then conducted a genome-wide association study in order to identify loci that influence them. We replicated associations of RNF212 with the mean rate in males and in females as well as the association of Inversion 17q21.31 with the female mean rate. We also replicated the association of PRDM9 with historical hotspot usage, finding that it explains most of the genetic variance in this phenotype. In addition, we identified a set of new candidate regions for further validation.These findings suggest that variation at broad and fine scales is largely separable and that, beyond three known loci, there is no evidence for common variation with large effects on recombination phenotypes.

  6. Variational approach to coarse-graining of generalized gradient flows

    NARCIS (Netherlands)

    Duong, M.H.; Lamacz, A.; Peletier, M.A.; Sharma, U.

    2017-01-01

    In this paper we present a variational technique that handles coarse-graining and passing to a limit in a unified manner. The technique is based on a duality structure, which is present in many gradient flows and other variational evolutions, and which often arises from a large-deviations principle.

  7. Amazing variational approach to chemical reactions

    OpenAIRE

    Fernández, Francisco M.

    2009-01-01

    In this letter we analyse an amazing variational approach to chemical reactions. Our results clearly show that the variational expressions are unsuitable for the analysis of empirical data obtained from chemical reactions.

  8. Temporal gene expression variation associated with eyespot size plasticity in Bicyclus anynana.

    Directory of Open Access Journals (Sweden)

    Jeffrey C Oliver

    Full Text Available Seasonal polyphenism demonstrates an organism's ability to respond to predictable environmental variation with alternative phenotypes, each presumably better suited to its respective environment. However, the molecular mechanisms linking environmental variation to alternative phenotypes via shifts in development remain relatively unknown. Here we investigate temporal gene expression variation in the seasonally polyphenic butterfly Bicyclus anynana. This species shows drastic changes in eyespot size depending on the temperature experienced during larval development. The wet season form (larvae reared over 24°C has large ventral wing eyespots while the dry season form (larvae reared under 19°C has much smaller eyespots. We compared the expression of three proteins, Notch, Engrailed, and Distal-less, in the future eyespot centers of the two forms to determine if eyespot size variation is associated with heterochronic shifts in the onset of their expression. For two of these proteins, Notch and Engrailed, expression in eyespot centers occurred earlier in dry season than in wet season larvae, while Distal-less showed no temporal difference between the two forms. These results suggest that differences between dry and wet season adult wings could be due to a delay in the onset of expression of these eyespot-associated genes. Early in eyespot development, Notch and Engrailed may be functioning as repressors rather than activators of the eyespot gene network. Alternatively, temporal variation in the onset of early expressed genes between forms may have no functional consequences to eyespot size regulation and may indicate the presence of an 'hourglass' model of development in butterfly eyespots.

  9. MORPHOLOGICAL VARIATIONS OF SPLEEN: A CADAVERIC STUDY

    Directory of Open Access Journals (Sweden)

    Siva Chidambaram

    2015-07-01

    Full Text Available The Spleen is a large lymphoid organ situated in the left hypochondrial region having an important role in immunological and hematological functions of the human body. The aim of this study was to find the morphological variations of the spleen with respect to it’s a Shape, b Number of notches on its borders and c Presence of anomalous fissure on its surface. The Study was done on 60 formalin fixed cadaveric spleen from the Department of Anatomy, Narayana Medical College, Nellore, Andhra Pradesh. Out of 60 spleens we examined, the various shapes of the spleen were noted suc h as wedge shape (73.33%, triangular (13.33%, tetrahedral (6.67% and oval shape(6.67%.The number of spleen showing notches on its superior border was 38(63.33% and in inferior border it was 6(10%. Absence of splenic notch was observed in 10(16.67% s pleens and the remaining 6 spleens (10% shows notches on its both the borders. The anomalous splenic fissure was found in 4(6.67% spleens on its diaphragmatic surface. The knowledge of variations in the morphology of spleen are essential for physician, s urgeon, radiologist and forensic surgeon to differentiate it from the splenic pathology and splenic injury. In addition to this, it is also important for anatomist during routine classroom dissection and discussion.

  10. Variation in prescribing for anxiety and depression: a reflection of health inequalities, cultural differences or variations in access to care?

    OpenAIRE

    Peters Jean; Grimsley Michael; Dibben Chris; Goyder Elizabeth; Blank Lindsay; Ellis Elizabeth

    2006-01-01

    Abstract Background There are large variations in mental health prescribing in UK populations. However the underlying reasons for these differences, which may be related to differences in prevalence, cultural expectations or practical difficulties in access to treatment, remain uncertain. Methods Linear modelling was used to investigate whether population characteristics or access to primary care account for variations in mental health prescribing across 39 deprived neighbourhoods. Results Th...

  11. Ladder variational autoencoders

    DEFF Research Database (Denmark)

    Sønderby, Casper Kaae; Raiko, Tapani; Maaløe, Lars

    2016-01-01

    Variational autoencoders are powerful models for unsupervised learning. However deep models with several layers of dependent stochastic variables are difficult to train which limits the improvements obtained using these highly expressive models. We propose a new inference model, the Ladder...... Variational Autoencoder, that recursively corrects the generative distribution by a data dependent approximate likelihood in a process resembling the recently proposed Ladder Network. We show that this model provides state of the art predictive log-likelihood and tighter log-likelihood lower bound compared...

  12. Ladder Variational Autoencoder

    DEFF Research Database (Denmark)

    Sønderby, Casper Kaae; Raiko, Tapani; Maaløe, Lars

    2016-01-01

    Variational autoencoders are powerful models for unsupervised learning. However deep models with several layers of dependent stochastic variables are difficult to train which limits the improvements obtained using these highly expressive models. We propose a new inference model, the Ladder...... Variational Autoencoder, that recursively corrects the generative distribution by a data dependent approximate likelihood in a process resembling the recently proposed Ladder Network. We show that this model provides state of the art predictive log-likelihood and tighter log-likelihood lower bound compared...

  13. Somatic Genetic Variation in Solid Pseudopapillary Tumor of the Pancreas by Whole Exome Sequencing

    Directory of Open Access Journals (Sweden)

    Meng Guo

    2017-01-01

    Full Text Available Solid pseudopapillary tumor of the pancreas (SPT is a rare pancreatic disease with a unique clinical manifestation. Although CTNNB1 gene mutations had been universally reported, genetic variation profiles of SPT are largely unidentified. We conducted whole exome sequencing in nine SPT patients to probe the SPT-specific insertions and deletions (indels and single nucleotide polymorphisms (SNPs. In total, 54 SNPs and 41 indels of prominent variations were demonstrated through parallel exome sequencing. We detected that CTNNB1 mutations presented throughout all patients studied (100%, and a higher count of SNPs was particularly detected in patients with older age, larger tumor, and metastatic disease. By aggregating 95 detected variation events and viewing the interconnections among each of the genes with variations, CTNNB1 was identified as the core portion in the network, which might collaborate with other events such as variations of USP9X, EP400, HTT, MED12, and PKD1 to regulate tumorigenesis. Pathway analysis showed that the events involved in other cancers had the potential to influence the progression of the SNPs count. Our study revealed an insight into the variation of the gene encoding region underlying solid-pseudopapillary neoplasm tumorigenesis. The detection of these variations might partly reflect the potential molecular mechanism.

  14. Large inter annual variation in air quality during the annual festival 'Diwali' in an Indian megacity.

    Science.gov (United States)

    Parkhi, Neha; Chate, Dilip; Ghude, Sachin D; Peshin, Sunil; Mahajan, Anoop; Srinivas, Reka; Surendran, Divya; Ali, Kaushar; Singh, Siddhartha; Trimbake, Hanumant; Beig, Gufran

    2016-05-01

    A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research (SAFAR) project in Delhi. We report observations of ozone (O3), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM2.5 and PM10) before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM10 and PM2.5 mass concentration is as high as 2070µg/m3 and 1620μg/m(3), respectively (24hr mean), which was about 20 and 27 times to National Ambient Air Quality Standards (NAAQS). For Diwali-2011, the increase in PM10 and PM2.5 mass concentrations was much less with their peaks of 600 and of 390μg/m(3) respectively, as compared to the background concentrations. Contrary to previous reports, firework display was not found to strongly influence the NOx, and O3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters. Copyright © 2015. Published by Elsevier B.V.

  15. Small-scale open ocean currents have large effects on wind wave heights

    Science.gov (United States)

    Ardhuin, Fabrice; Gille, Sarah T.; Menemenlis, Dimitris; Rocha, Cesar B.; Rascle, Nicolas; Chapron, Bertrand; Gula, Jonathan; Molemaker, Jeroen

    2017-06-01

    Tidal currents and large-scale oceanic currents are known to modify ocean wave properties, causing extreme sea states that are a hazard to navigation. Recent advances in the understanding and modeling capability of open ocean currents have revealed the ubiquitous presence of eddies, fronts, and filaments at scales 10-100 km. Based on realistic numerical models, we show that these structures can be the main source of variability in significant wave heights at scales less than 200 km, including important variations down to 10 km. Model results are consistent with wave height variations along satellite altimeter tracks, resolved at scales larger than 50 km. The spectrum of significant wave heights is found to be of the order of 70>>2/>(g2>>2>) times the current spectrum, where >> is the spatially averaged significant wave height, >> is the energy-averaged period, and g is the gravity acceleration. This variability induced by currents has been largely overlooked in spite of its relevance for extreme wave heights and remote sensing.Plain Language SummaryWe show that the variations in currents at scales 10 to 100 km are the main source of variations in wave heights at the same scales. Our work uses a combination of realistic numerical models for currents and waves and data from the Jason-3 and SARAL/AltiKa satellites. This finding will be of interest for the investigation of extreme wave heights, remote sensing, and air-sea interactions. As an immediate application, the present results will help constrain the error budget of the up-coming satellite missions, in particular the Surface Water and Ocean Topography (SWOT) mission, and decide how the data will have to be processed to arrive at accurate sea level and wave measurements. It will also help in the analysis of wave measurements by the CFOSAT satellite.

  16. Parametric study of variation in cargo-airplane performance related to progression from current to spanloader designs

    Science.gov (United States)

    Toll, T. A.

    1980-01-01

    A parametric analysis was made to investigate the relationship between current cargo airplanes and possible future designs that may differ greatly in both size and configuration. The method makes use of empirical scaling laws developed from statistical studies of data from current and advanced airplanes and, in addition, accounts for payload density, effects of span distributed load, and variations in tail area ratio. The method is believed to be particularly useful for exploratory studies of design and technology options for large airplanes. The analysis predicts somewhat more favorable variations of the ratios of payload to gross weight and block fuel to payload as the airplane size is increased than has been generally understood from interpretations of the cube-square law. In terms of these same ratios, large all wing (spanloader) designs show an advantage over wing-fuselage designs.

  17. Anomalous width variation of rarefactive ion acoustic solitary waves in the context of auroral plasmas

    Directory of Open Access Journals (Sweden)

    S. S. Ghosh

    2004-01-01

    Full Text Available The presence of dynamic, large amplitude solitary waves in the auroral regions of space is well known. Since their velocities are of the order of the ion acoustic speed, they may well be considered as being generated from the nonlinear evolution of ion acoustic waves. However, they do not show the expected width-amplitude correlation for K-dV solitons. Recent POLAR observations have actually revealed that the low altitude rarefactive ion acoustic solitary waves are associated with an increase in the width with increasing amplitude. This indicates that a weakly nonlinear theory is not appropriate to describe the solitary structures in the auroral regions. In the present work, a fully nonlinear analysis based on Sagdeev pseudopotential technique has been adopted for both parallel and oblique propagation of rarefactive solitary waves in a two electron temperature multi-ion plasma. The large amplitude solutions have consistently shown an increase in the width with increasing amplitude. The width-amplitude variation profile of obliquely propagating rarefactive solitary waves in a magnetized plasma have been compared with the recent POLAR observations. The width-amplitude variation pattern is found to fit well with the analytical results. It indicates that a fully nonlinear theory of ion acoustic solitary waves may well explain the observed anomalous width variations of large amplitude structures in the auroral region.

  18. Limit theorems for power variations of ambit field driven by white noise

    DEFF Research Database (Denmark)

    Pakkanen, Mikko S.

    2014-01-01

    We study the asymptotics of lattice power variations of two-parameter ambit fields driven by white noise. Our first result is a law of large numbers for power variations. Under a constraint on the memory of the ambit field, normalized power variations converge to certain integral functionals...

  19. Diurnal and Seasonal Variations in Mid-Latitude Geomagnetic Field During International Quiet Days: BOH Magnetometer

    Directory of Open Access Journals (Sweden)

    Junga Hwang

    2012-12-01

    Full Text Available Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Bohyunsan Observatory to measure the Earth's magnetic field variations in South Korea. In 2007, we installed a fluxgate magnetometer (RFP-523C to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we use the H, D, Z components of fluxgate magnetometer data to investigate the characteristics of mid-latitude geomagnetic field variation. To remove the temporary changes in Earth’s geomagnetic filed by space weather, we use the international quiet days’ data only. In other words, we performed a superposed epoch analysis using five days per each month during 2008-2011. We find that daily variations of H, D, and Z shows similar tendency compared to previous results using all days. That is, H, D, Z all three components’ quiet intervals terminate near the sunrise and shows maximum 2-3 hours after the culmination and the quiet interval start from near the sunset. Seasonal variations show similar dependences to the Sun. As it becomes hot season, the geomagnetic field variation’s amplitude becomes large and the quiet interval becomes shortened. It is well-known that these variations are effects of Sq current system in the Earth’s atmosphere. We confirm that the typical mid-latitude geomagnetic field variations due to the Sq current system by excluding all possible association with the space weather.

  20. Atmospheric Structure and Diurnal Variations at Low Altitudes in the Martian Tropics

    Science.gov (United States)

    Hinson, David P.; Spiga, A.; Lewis, S.; Tellmann, S.; Pätzold, M.; Asmar, S.; Häusler, B.

    2013-10-01

    We are using radio occultation measurements from Mars Express, Mars Reconnaissance Orbiter, and Mars Global Surveyor to characterize the diurnal cycle in the lowest scale height above the surface. We focus on northern spring and summer, using observations from 4 Martian years at local times of 4-5 and 15-17 h. We supplement the observations with results obtained from large-eddy simulations and through data assimilation by the UK spectral version of the LMD Mars Global Circulation Model. We previously investigated the depth of the daytime convective boundary layer (CBL) and its variations with surface elevation and surface properties. We are now examining unusual aspects of the temperature structure observed at night. Most important, predawn profiles in the Tharsis region contain an unexpected layer of neutral static stability at pressures of 200-300 Pa with a depth of 4-5 km. The mixed layer is bounded above by a midlevel temperature inversion and below by another strong inversion adjacent to the surface. The narrow temperature minimum at the base of the midlevel inversion suggests the presence of a water ice cloud layer, with the further implication that radiative cooling at cloud level can induce convective activity at lower altitudes. Conversely, nighttime profiles in Amazonis show no sign of a midlevel inversion or a detached mixed layer. These regional variations in the nighttime temperature structure appear to arise in part from large-scale variations in topography, which have several notable effects. First, the CBL is much deeper in the Tharsis region than in Amazonis, owing to a roughly 6-km difference in surface elevation. Second, large-eddy simulations show that daytime convection is not only deeper above Tharsis but also considerably more intense than it is in Amazonis. Finally, the daytime surface temperatures are comparable in the two regions, so that Tharsis acts as an elevated heat source throughout the CBL. These topographic effects are expected to

  1. Multiply to conquer: Copy number variations at Ppd-B1 and Vrn-A1 facilitate global adaptation in wheat.

    Science.gov (United States)

    Würschum, Tobias; Boeven, Philipp H G; Langer, Simon M; Longin, C Friedrich H; Leiser, Willmar L

    2015-07-29

    Copy number variation was found to be a frequent type of DNA polymorphism in the human genome often associated with diseases but its importance in crops and the effects on agronomic traits are still largely unknown. Here, we employed a large worldwide panel of 1110 winter wheat varieties to assess the frequency and the geographic distribution of copy number variants at the Photoperiod-B1 (Ppd-B1) and the Vernalization-A1 (Vrn-A1) loci as well as their effects on flowering time under field conditions. We identified a novel four copy variant of Vrn-A1 and based on the phylogenetic relationships among the lines show that the higher copy variants at both loci are likely to have arisen independently multiple times. In addition, we found that the frequency of the different copy number variants at both loci reflects the environmental conditions in the varieties' region of origin and based on multi-location field trials show that Ppd-B1 copy number has a substantial effect on the fine-tuning of flowering time. In conclusion, our results show the importance of copy number variation at Ppd-B1 and Vrn-A1 for the global adaptation of wheat making it a key factor for wheat success in a broad range of environments and in a wider context substantiate the significant role of copy number variation in crops.

  2. Tensors, differential forms, and variational principles

    CERN Document Server

    Lovelock, David

    1989-01-01

    Incisive, self-contained account of tensor analysis and the calculus of exterior differential forms, interaction between the concept of invariance and the calculus of variations. Emphasis is on analytical techniques, with large number of problems, from routine manipulative exercises to technically difficult assignments.

  3. Population genetic variation in gene expression is associated withphenotypic variation in Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Fay, Justin C.; McCullough, Heather L.; Sniegowski, Paul D.; Eisen, Michael B.

    2004-02-25

    The relationship between genetic variation in gene expression and phenotypic variation observable in nature is not well understood. Identifying how many phenotypes are associated with differences in gene expression and how many gene-expression differences are associated with a phenotype is important to understanding the molecular basis and evolution of complex traits. Results: We compared levels of gene expression among nine natural isolates of Saccharomyces cerevisiae grown either in the presence or absence of copper sulfate. Of the nine strains, two show a reduced growth rate and two others are rust colored in the presence of copper sulfate. We identified 633 genes that show significant differences in expression among strains. Of these genes,20 were correlated with resistance to copper sulfate and 24 were correlated with rust coloration. The function of these genes in combination with their expression pattern suggests the presence of both correlative and causative expression differences. But the majority of differentially expressed genes were not correlated with either phenotype and showed the same expression pattern both in the presence and absence of copper sulfate. To determine whether these expression differences may contribute to phenotypic variation under other environmental conditions, we examined one phenotype, freeze tolerance, predicted by the differential expression of the aquaporin gene AQY2. We found freeze tolerance is associated with the expression of AQY2. Conclusions: Gene expression differences provide substantial insight into the molecular basis of naturally occurring traits and can be used to predict environment dependent phenotypic variation.

  4. Genetic Variation in Cardiomyopathy and Cardiovascular Disorders.

    Science.gov (United States)

    McNally, Elizabeth M; Puckelwartz, Megan J

    2015-01-01

    With the wider deployment of massively-parallel, next-generation sequencing, it is now possible to survey human genome data for research and clinical purposes. The reduced cost of producing short-read sequencing has now shifted the burden to data analysis. Analysis of genome sequencing remains challenged by the complexity of the human genome, including redundancy and the repetitive nature of genome elements and the large amount of variation in individual genomes. Public databases of human genome sequences greatly facilitate interpretation of common and rare genetic variation, although linking database sequence information to detailed clinical information is limited by privacy and practical issues. Genetic variation is a rich source of knowledge for cardiovascular disease because many, if not all, cardiovascular disorders are highly heritable. The role of rare genetic variation in predicting risk and complications of cardiovascular diseases has been well established for hypertrophic and dilated cardiomyopathy, where the number of genes that are linked to these disorders is growing. Bolstered by family data, where genetic variants segregate with disease, rare variation can be linked to specific genetic variation that offers profound diagnostic information. Understanding genetic variation in cardiomyopathy is likely to help stratify forms of heart failure and guide therapy. Ultimately, genetic variation may be amenable to gene correction and gene editing strategies.

  5. Water quality, Multivariate statistical techniques, submarine out fall, spatial variation, temporal variation

    International Nuclear Information System (INIS)

    Garcia, Francisco; Palacio, Carlos; Garcia, Uriel

    2012-01-01

    Multivariate statistical techniques were used to investigate the temporal and spatial variations of water quality at the Santa Marta coastal area where a submarine out fall that discharges 1 m3/s of domestic wastewater is located. Two-way analysis of variance (ANOVA), cluster and principal component analysis and Krigging interpolation were considered for this report. Temporal variation showed two heterogeneous periods. From December to April, and July, where the concentration of the water quality parameters is higher; the rest of the year (May, June, August-November) were significantly lower. The spatial variation reported two areas where the water quality is different, this difference is related to the proximity to the submarine out fall discharge.

  6. Limit theorems for power variations of ambit fields driven by white noise

    DEFF Research Database (Denmark)

    Pakkanen, Mikko

    We study the asymptotic behavior of lattice power variations of two-parameter ambit fields that are driven by white noise. Our first result is a law of large numbers for such power variations. Under a constraint on the memory of the ambit field, normalized power variations are shown to converge...

  7. A wireless sensor network design and evaluation for large structural strain field monitoring

    International Nuclear Information System (INIS)

    Qiu, Zixue; Wu, Jian; Yuan, Shenfang

    2011-01-01

    Structural strain changes under external environmental or mechanical loads are the main monitoring parameters in structural health monitoring or mechanical property tests. This paper presents a wireless sensor network designed for monitoring large structural strain field variation. First of all, a precision strain sensor node is designed for multi-channel strain gauge signal conditioning and wireless monitoring. In order to establish a synchronous strain data acquisition network, the cluster-star network synchronization method is designed in detail. To verify the functionality of the designed wireless network for strain field monitoring capability, a multi-point network evaluation system is developed for an experimental aluminum plate structure for load variation monitoring. Based on the precision wireless strain nodes, the wireless data acquisition network is deployed to synchronously gather, process and transmit strain gauge signals and monitor results under concentrated loads. This paper shows the efficiency of the wireless sensor network for large structural strain field monitoring

  8. Study of New FNAL-NICADD Extruded Scintillator as Active Media of Large EMCal of ALICE at LHC

    CERN Document Server

    Grachov, Oleg A.; Pla-Dalmau, A.; Bross, A.; Rykalin, V.

    2006-01-01

    The current conceptual design of proposed Large EMCal of ALICE at LHC is based largely on the scintillating mega-tile/fiber technology implemented in CDF Endplug upgrade project and in both barrel and endcap electromagnetic calorimeters of the STAR. The cost of scintillating material leads us to the choice of extruded polystyrene based scintillator, which is available in new FNAL-NICADD facility. Result of optical measurements, such as light yield and light yield variation, show that it is possible to use this material as active media of Large EMCal of ALICE at LHC.

  9. Genome-wide recombination dynamics are associated with phenotypic variation in maize.

    Science.gov (United States)

    Pan, Qingchun; Li, Lin; Yang, Xiaohong; Tong, Hao; Xu, Shutu; Li, Zhigang; Li, Weiya; Muehlbauer, Gary J; Li, Jiansheng; Yan, Jianbing

    2016-05-01

    Meiotic recombination is a major driver of genetic diversity, species evolution, and agricultural improvement. Thus, an understanding of the genetic recombination landscape across the maize (Zea mays) genome will provide insight and tools for further study of maize evolution and improvement. Here, we used c. 50 000 single nucleotide polymorphisms to precisely map recombination events in 12 artificial maize segregating populations. We observed substantial variation in the recombination frequency and distribution along the ten maize chromosomes among the 12 populations and identified 143 recombination hot regions. Recombination breakpoints were partitioned into intragenic and intergenic events. Interestingly, an increase in the number of genes containing recombination events was accompanied by a decrease in the number of recombination events per gene. This kept the overall number of intragenic recombination events nearly invariable in a given population, suggesting that the recombination variation observed among populations was largely attributed to intergenic recombination. However, significant associations between intragenic recombination events and variation in gene expression and agronomic traits were observed, suggesting potential roles for intragenic recombination in plant phenotypic diversity. Our results provide a comprehensive view of the maize recombination landscape, and show an association between recombination, gene expression and phenotypic variation, which may enhance crop genetic improvement. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  10. Causes and significance of variation in mammalian basal metabolism.

    Science.gov (United States)

    Raichlen, David A; Gordon, Adam D; Muchlinski, Magdalena N; Snodgrass, J Josh

    2010-02-01

    Mammalian basal metabolic rates (BMR) increase with body mass, whichs explains approximately 95% of the variation in BMR. However, at a given mass, there remains a large amount of variation in BMR. While many researchers suggest that the overall scaling of BMR with body mass is due to physiological constraints, variation at a given body mass may provide clues as to how selection acts on BMR. Here, we examine this variation in BMR in a broad sample of mammals and we test the hypothesis that, across mammals, body composition explains differences in BMR at a given body mass. Variation in BMR is strongly correlated with variation in muscle mass, and both of these variables are correlated with latitude and ambient temperature. These results suggest that selection alters BMR in response to thermoregulatory pressures, and that selection uses muscle mass as a means to generate this variation.

  11. Large scale study on the variation of RF energy absorption in the head & brain regions of adults and children and evaluation of the SAM phantom conservativeness

    Science.gov (United States)

    Keshvari, J.; Kivento, M.; Christ, A.; Bit-Babik, G.

    2016-04-01

    This paper presents the results of two computational large scale studies using highly realistic exposure scenarios, MRI based human head and hand models, and two mobile phone models. The objectives are (i) to study the relevance of age when people are exposed to RF by comparing adult and child heads and (ii) to analyze and discuss the conservativeness of the SAM phantom for all age groups. Representative use conditions were simulated using detailed CAD models of two mobile phones operating between 900 MHz and 1950 MHz including configurations with the hand holding the phone, which were not considered in most previous studies. The peak spatial-average specific absorption rate (psSAR) in the head and the pinna tissues is assessed using anatomically accurate head and hand models. The first of the two mentioned studies involved nine head-, four hand- and two phone-models, the second study included six head-, four hand- and three simplified phone-models (over 400 configurations in total). In addition, both studies also evaluated the exposure using the SAM phantom. Results show no systematic differences between psSAR induced in the adult and child heads. The exposure level and its variation for different age groups may be different for particular phones, but no correlation between psSAR and model age was found. The psSAR from all exposure conditions was compared to the corresponding configurations using SAM, which was found to be conservative in the large majority of cases.

  12. Geographic variation in fee-for-service medicare beneficiaries' medical costs is largely explained by disease burden.

    Science.gov (United States)

    Reschovsky, James D; Hadley, Jack; Romano, Patrick S

    2013-10-01

    Control for area differences in population health (casemix adjustment) is necessary to measure geographic variations in medical spending. Studies use various casemix adjustment methods, resulting in very different geographic variation estimates. We study casemix adjustment methodological issues and evaluate alternative approaches using claims from 1.6 million Medicare beneficiaries in 60 representative communities. Two key casemix adjustment methods-controlling for patient conditions obtained from diagnoses on claims and expenditures of those at the end of life-were evaluated. We failed to find evidence of bias in the former approach attributable to area differences in physician diagnostic patterns, as others have found, and found that the assumption underpinning the latter approach-that persons close to death are equally sick across areas-cannot be supported. Diagnosis-based approaches are more appropriate when current rather than prior year diagnoses are used. Population health likely explains more than 75% to 85% of cost variations across fixed sets of areas.

  13. Higher frequency of social learning in China than in the West shows cultural variation in the dynamics of cultural evolution.

    Science.gov (United States)

    Mesoudi, Alex; Chang, Lei; Murray, Keelin; Lu, Hui Jing

    2015-01-07

    Cultural evolutionary models have identified a range of conditions under which social learning (copying others) is predicted to be adaptive relative to asocial learning (learning on one's own), particularly in humans where socially learned information can accumulate over successive generations. However, cultural evolution and behavioural economics experiments have consistently shown apparently maladaptive under-utilization of social information in Western populations. Here we provide experimental evidence of cultural variation in people's use of social learning, potentially explaining this mismatch. People in mainland China showed significantly more social learning than British people in an artefact-design task designed to assess the adaptiveness of social information use. People in Hong Kong, and Chinese immigrants in the UK, resembled British people in their social information use, suggesting a recent shift in these groups from social to asocial learning due to exposure to Western culture. Finally, Chinese mainland participants responded less than other participants to increased environmental change within the task. Our results suggest that learning strategies in humans are culturally variable and not genetically fixed, necessitating the study of the 'social learning of social learning strategies' whereby the dynamics of cultural evolution are responsive to social processes, such as migration, education and globalization.

  14. Genetic variation assessed with microsatellites in mass selection lines of the Pacific oyster ( Crassostrea gigas) in China

    Science.gov (United States)

    Wang, Xubo; Li, Qi; Yu, Hong; Kong, Lingfeng

    2016-12-01

    Four successive mass selection lines of the Pacific oyster, Crassostrea gigas, selected for faster growth in breeding programs in China were examined at ten polymorphic microsatellite loci to assess the level of allelic diversity and estimate the effective population size. These data were compared with those of their base population. The results showed that the genetic variation of the four generations were maintained at high levels with an average allelic richness of 18.8-20.6, and a mean expected heterozygosity of 0.902-0.921. They were not reduced compared with those of their base population. Estimated effective population sizes based on temporal variances in microsatellite frequencies were smaller to that of sex ratio-corrected broodstock count estimates. Using a relatively large number of broodstock and keeping an equal sex ratio in the broodstock each generation may have contributed to retaining the original genetic diversity and maintaining relatively large effective population size. The results obtained in this study showed that the genetic variation was not affected greatly by mass selection progress and high genetic variation still existed in the mass selection lines, suggesting that there is still potential for increasing the gains in future generations of C. gigas. The present study provided important information for future genetic improvement by selective breeding, and for the design of suitable management guidelines for genetic breeding of C. gigas.

  15. Morphological Variation in Anuran Limbs: Constraints and Novelties.

    Science.gov (United States)

    Fabrezi, Marissa; Goldberg, Javier; Chuliver Pereyra, Mariana

    2017-09-01

    Anurans have three primary types of locomotion: walking, jumping, and swimming. Additionally, they may dig, climb, grasp, etc. All adult anurans have four limbs, with four fingers on the hands and five toes on the feet. We summarized and updated knowledge on the interspecific variation within anuran limbs, then discuss how developmental constraints (e.g., in size) and novelties may have influenced anuran diversification through the locomotion. We analyze morphological variation from limb bud stages up to the final limb form resulting from certain skeletal organization and growth. We find limited morphometric variations in the skeleton of different developmental modules (i.e., skull, trunk, urostyle, limbs) indicate that the anuran body shape is largely constrained. We identify specializations of the stylopodium, zeugopodium, and proximal carpals/tarsals that have evolved to facilitiate saltatorial locomotion. We show that the anuran prepollex and prehallux are not vestigial digits and that they have come to serve specialized function. Medial rotation of the manus in anurans appears to have evolved to help distribute the force of impact upon landing at the end of a jump. Additional skeletal elements in anuran limbs are intercalary elements and sesamoids. The intercalary elements appear within neobatrachians and are integrated with digital pads in lineages capable of locomotion on smooth vertical surfaces. They have allowed arboreal anurans to occupy a wide range of arboreal habitats. © 2017 Wiley Periodicals, Inc.

  16. Temporal variation and provenance of thorium deposition observed at Tsukuba, Japan

    International Nuclear Information System (INIS)

    Hirose, Katsumi; Kikawada, Yoshikazu; Igarashi, Yasuhito

    2012-01-01

    Temporal variations of monthly thorium (Th) deposition observed at Tsukuba, Japan during the period 1990–2007, comparing with plutonium deposition, was studied. The monthly 232 Th deposition as did 239,240 Pu, varied according to season and inter-annually. In particular, 232 Th deposition increased significantly in spring coinciding with Asian dust (Kosa) events. The 230 Th/ 232 Th activity ratios vary according to sources and can therefore be used to differentiate between locally derived and remotely derived 232 Th. The 230 Th/ 232 Th activity ratios in deposition samples showed large variability with high ratios occurring in early spring. These high 230 Th/ 232 Th ratios in deposition can be attributed to local dust storms, especially in early spring, that cause resuspension of soils from cultivated fields which are characterized by high 230 Th/ 232 Th activity ratios. The results reveal that both locally and remotely derived 232 Th deposition showed seasonal variations with maxima in spring, although the remotely derived fraction is dominant rather than the locally derived one. The 232 Th deposition maxima later in spring is attributable to the remotely derived fraction, corresponding to the Kosa events. Annual 232 Th deposition exhibited an increasing trend, suggesting the presence of sources other than soil dust such as fly ash from increasing coal burning. - Highlights: ► We show monthly Th deposition observed at Tsukuba, Japan from 1990 to 2007. ► The Th deposition shows a seasonal variation and inter-annual variability. ► Th isotope ratios ( 230 Th/ 232 Th) are used to identify its sources. ► The long-term trend of Th deposition is related to increasing anthropogenic input.

  17. Confidence bounds for normal and lognormal distribution coefficients of variation

    Science.gov (United States)

    Steve Verrill

    2003-01-01

    This paper compares the so-called exact approach for obtaining confidence intervals on normal distribution coefficients of variation to approximate methods. Approximate approaches were found to perform less well than the exact approach for large coefficients of variation and small sample sizes. Web-based computer programs are described for calculating confidence...

  18. Genetic variation in social influence on mate preferences

    Science.gov (United States)

    Rebar, Darren; Rodríguez, Rafael L.

    2013-01-01

    Patterns of phenotypic variation arise in part from plasticity owing to social interactions, and these patterns contribute, in turn, to the form of selection that shapes the variation we observe in natural populations. This proximate–ultimate dynamic brings genetic variation in social environments to the forefront of evolutionary theory. However, the extent of this variation remains largely unknown. Here, we use a member of the Enchenopa binotata species complex of treehoppers (Hemiptera: Membracidae) to assess how mate preferences are influenced by genetic variation in the social environment. We used full-sibling split-families as ‘treatment’ social environments, and reared focal females alongside each treatment family, describing the mate preferences of the focal females. With this method, we detected substantial genetic variation in social influence on mate preferences. The mate preferences of focal females varied according to the treatment families along with which they grew up. We discuss the evolutionary implications of the presence of such genetic variation in social influence on mate preferences, including potential contributions to the maintenance of genetic variation, the promotion of divergence, and the adaptive evolution of social effects on fitness-related traits. PMID:23698010

  19. An analysis of cross-sectional variations in total household energy requirements in India using micro survey data

    International Nuclear Information System (INIS)

    Pachauri, Shonali

    2004-01-01

    Using micro level household survey data from India, we analyse the variation in the pattern and quantum of household energy requirements, both direct and indirect, and the factors causing such variation. An econometric analysis using household survey data from India for the year 1993-1994 reveals that household socio-economic, demographic, geographic, family and dwelling attributes influence the total household energy requirements. There are also large variations in the pattern of energy requirements across households belonging to different expenditure classes. Results from the econometric estimation show that total household expenditure or income level is the most important explanatory variable causing variation in energy requirements across households. In addition, the size of the household dwelling and the age of the head of the household are related to higher household energy requirements. In contrast, the number of members in the household and literacy of the head are associated with lower household energy requirements

  20. An analysis of cross-sectional variations in total household energy requirements in India using micro survey data

    Energy Technology Data Exchange (ETDEWEB)

    Pachauri, Shonali E-mail: shonali.pachauri@cepe.mavt.ethz.ch

    2004-10-01

    Using micro level household survey data from India, we analyse the variation in the pattern and quantum of household energy requirements, both direct and indirect, and the factors causing such variation. An econometric analysis using household survey data from India for the year 1993-1994 reveals that household socio-economic, demographic, geographic, family and dwelling attributes influence the total household energy requirements. There are also large variations in the pattern of energy requirements across households belonging to different expenditure classes. Results from the econometric estimation show that total household expenditure or income level is the most important explanatory variable causing variation in energy requirements across households. In addition, the size of the household dwelling and the age of the head of the household are related to higher household energy requirements. In contrast, the number of members in the household and literacy of the head are associated with lower household energy requirements.

  1. Radon in Austrian tourist mines and show caves

    International Nuclear Information System (INIS)

    Ringer, W.; Graeser, J.

    2009-01-01

    The radon situation in tourist mines and show caves is barely investigated in Austria. This paper investigates the influence of its determining factors, such as climate, structure and geology. For this purpose, long-term time-resolved measurements over 6 to 12 months in 4 tourist mines and 2 show caves - with 5 to 9 measuring points each - have been carried out to obtain the course of radon concentration throughout the year. In addition, temperature and air-pressure were measured and compared to the data outside where available. Results suggest that the dominating factors of the average radon concentration are structure and location (geology) of the tunnel-system, whereas the diurnal and annual variation is mainly caused by the changing airflow, which is driven by the difference in temperature inside and outside. Downcast air is connected with very low radon concentrations, upcast air with high concentrations. In some locations the maximum values appear when the airflow ceases. But airflow can be different in different parts of mines and caves. Systems close to the surface show generally lower radon levels than the ones located deeper underground. Due to variation of structure, geology and local climate, the radon situation in mines and caves can only be described by simultaneous measurements at several measuring points. (orig.)

  2. Large-scale spatial variation in mercury concentrations in cattle in NW Spain

    International Nuclear Information System (INIS)

    Lopez Alonso, M.; Benedito, J.L.; Miranda, M.; Fernandez, J.A.; Castillo, C.; Hernandez, J.; Shore, R.F.

    2003-01-01

    This study quantifies the spatial scale over which major point and diffuse sources of anthropogenic mercury emission affect mercury accumulation by cattle in northwest Spain. - Mercury (Hg) is a highly toxic environmental contaminant and man-made emissions account for between a quarter and a third of total atmospheric levels. Point discharges, particularly coal-burning power stations, are major sources of atmospheric Hg and can result in marked spatial variation in mercury deposition and subsequent uptake by biota. The aims of this study were to quantify the extent to which major point and diffuse sources of atmospheric Hg emissions affected accumulation of Hg by biota throughout Galicia and Asturias, two of the major regions in northwest Spain. We did this by relating renal Hg concentrations in locally reared cattle (n=284) to the proximity of animals to point and diffuse sources of Hg emissions. Mercury residues in calf kidneys ranged between non-detected and 89.4 μg/kg wet weight. Point discharges from coal-fired power plants in Galicia had the most dominant impact on Hg accumulation by calves in Galicia, affecting animals throughout the region and explaining some two-thirds of the variation in renal residues between animals located directly downwind from the plants. The effects of more diffuse emission sources on Hg accumulation in calves were not distinguishable in Galicia but were detected in cattle from neighbouring Asturias. The impact of both point and diffuse sources in elevating environmental levels of bioavailable Hg and subsequent accumulation by cattle extended to approximately 140-200 km downwind from source

  3. Gauging Variational Inference

    Energy Technology Data Exchange (ETDEWEB)

    Chertkov, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ahn, Sungsoo [Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of); Shin, Jinwoo [Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of)

    2017-05-25

    Computing partition function is the most important statistical inference task arising in applications of Graphical Models (GM). Since it is computationally intractable, approximate methods have been used to resolve the issue in practice, where meanfield (MF) and belief propagation (BP) are arguably the most popular and successful approaches of a variational type. In this paper, we propose two new variational schemes, coined Gauged-MF (G-MF) and Gauged-BP (G-BP), improving MF and BP, respectively. Both provide lower bounds for the partition function by utilizing the so-called gauge transformation which modifies factors of GM while keeping the partition function invariant. Moreover, we prove that both G-MF and G-BP are exact for GMs with a single loop of a special structure, even though the bare MF and BP perform badly in this case. Our extensive experiments, on complete GMs of relatively small size and on large GM (up-to 300 variables) confirm that the newly proposed algorithms outperform and generalize MF and BP.

  4. Wing shape variation associated with mimicry in butterflies.

    Science.gov (United States)

    Jones, Robert T; Le Poul, Yann; Whibley, Annabel C; Mérot, Claire; ffrench-Constant, Richard H; Joron, Mathieu

    2013-08-01

    Mimetic resemblance in unpalatable butterflies has been studied by evolutionary biologists for over a century, but has largely focused on the convergence in wing color patterns. In Heliconius numata, discrete color-pattern morphs closely resemble comimics in the distantly related genus Melinaea. We examine the possibility that the shape of the butterfly wing also shows adaptive convergence. First, simple measures of forewing dimensions were taken of individuals in a cross between H. numata morphs, and showed quantitative differences between two of the segregating morphs, f. elegans and f. silvana. Second, landmark-based geometric morphometric and elliptical Fourier outline analyses were used to more fully characterize these shape differences. Extension of these techniques to specimens from natural populations suggested that, although many of the coexisting morphs could not be discriminated by shape, the differences we identified between f. elegans and f. silvana hold in the wild. Interestingly, despite extensive overlap, the shape variation between these two morphs is paralleled in their respective Melinaea comimics. Our study therefore suggests that wing-shape variation is associated with mimetic resemblance, and raises the intriguing possibility that the supergene responsible for controlling the major switch in color pattern between morphs also contributes to wing shape differences in H. numata. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  5. Luminosity Variations in Post-AGB Stars

    Science.gov (United States)

    Mesler, Robert; Henson, G.

    2007-12-01

    Although much is known about AGB stars and planetary nebulae, relatively little is known about the phase of a star's life in which it transitions between those two states. We have measured the variations in luminosity of a sample of known Post-AGB stars (as well as several candidates) relative to nearby, non-variable stars in order to compare them with theoretical models. The typical behavior of the observed variations is described and an attempt is made to discern whether any periodicity might be present. Luminosity variations were found to be on the order of a few hundredths to a few tenths of a magnitude for the stars that were surveyed, with occasional fluctuations of up to a magnitude. This agrees with current models of Post-AGB stars. Each star fell into one of three categories, which were termed groups 1, 2, and 3. Group 1 stars showed long term, non-periodic luminosity variations on the scale of weeks or longer and were most likely to display some sort of short term, coherent luminosity oscillation (each of which lasted for only a few cycles). Group 2 stars showed erratic, short-term magnitude variations occurring on scales of several days. Group 3 stars showed little or no variation in magnitude. Of the 27 Post-AGB stars that were sampled, five fell into group 1, fifteen fell into group 2, and seven fell into group 3. The luminosity variations tended to be color-independent, and occurred on timescales ranging nearly continuously from a few days to more than a year. No clear periodic behavior was found in any star in our sample. This project was funded by a partnership between the National Science Foundation (NSF AST-0552798), Research Experiences for Undergraduates (REU), and the Department of Defense (DoD) ASSURE (Awards to Stimulate and Support Undergraduate Research Experiences) programs.

  6. Variation and control of soil organic carbon and other nutrients in permafrost regions on central Qinghai-Tibetan Plateau

    International Nuclear Information System (INIS)

    Liu, Wenjie; Chen, Shengyun; Zhao, Qian; Ren, Jiawen; Qin, Dahe; Sun, Zhizhong

    2014-01-01

    The variation and control of soil organic carbon (SOC) and other nutrients in permafrost regions are critical for studying the carbon cycle and its potential feedbacks to climate change; however, they are poorly understood. Soil nutrients samples at depths of 0–10, 10–20, 20–30, and 30–40 cm, were sampled eight times in 2009 in alpine swamp meadow, alpine meadow and alpine steppe in permafrost regions of the central Qinghai-Tibetan Plateau. SOC and total nitrogen (TN) in the alpine swamp meadow and meadow decreased with soil depth, whereas the highest SOC content in the alpine steppe was found at depths of 20–30 cm. The vertical profiles of total and available phosphorus (P) and potassium (K) were relatively uniform for all the three grassland types. Correlation and linear regression analyses showed that soil moisture (SM) was the most important parameter for the vertical variation of SOC and other soil nutrients, and that belowground biomass (BGB) was the main source of SOC and TN. The spatial variations (including seasonal variation) of SOC and TN at plot scale were large. The relative deviation of SOC ranged from 7.18 to 41.50 in the alpine swamp meadow, from 2.88 to 35.91 in the alpine meadow, and from 9.33 to 68.38 in the alpine steppe. The spatial variations in the other soil nutrients varied among different grassland types. The most important factors for spatial variations (including seasonal variation) of SOC, TN, total P, available P, and both total and available K were: SM, SM and temperature, SM, air temperature, and SM and BGB, respectively. The large variation in the three grassland types implies that spatial variation at plot scale should be considered when estimating SOC storage and its dynamics. (letter)

  7. Application of Satellite Solar-Induced Chlorophyll Fluorescence to Understanding Large-Scale Variations in Vegetation Phenology and Function Over Northern High Latitude Forests

    Science.gov (United States)

    Jeong, Su-Jong; Schimel, David; Frankenberg, Christian; Drewry, Darren T.; Fisher, Joshua B.; Verma, Manish; Berry, Joseph A.; Lee, Jung-Eun; Joiner, Joanna

    2016-01-01

    This study evaluates the large-scale seasonal phenology and physiology of vegetation over northern high latitude forests (40 deg - 55 deg N) during spring and fall by using remote sensing of solar-induced chlorophyll fluorescence (SIF), normalized difference vegetation index (NDVI) and observation-based estimate of gross primary productivity (GPP) from 2009 to 2011. Based on GPP phenology estimation in GPP, the growing season determined by SIF time-series is shorter in length than the growing season length determined solely using NDVI. This is mainly due to the extended period of high NDVI values, as compared to SIF, by about 46 days (+/-11 days), indicating a large-scale seasonal decoupling of physiological activity and changes in greenness in the fall. In addition to phenological timing, mean seasonal NDVI and SIF have different responses to temperature changes throughout the growing season. We observed that both NDVI and SIF linearly increased with temperature increases throughout the spring. However, in the fall, although NDVI linearly responded to temperature increases, SIF and GPP did not linearly increase with temperature increases, implying a seasonal hysteresis of SIF and GPP in response to temperature changes across boreal ecosystems throughout their growing season. Seasonal hysteresis of vegetation at large-scales is consistent with the known phenomena that light limits boreal forest ecosystem productivity in the fall. Our results suggest that continuing measurements from satellite remote sensing of both SIF and NDVI can help to understand the differences between, and information carried by, seasonal variations vegetation structure and greenness and physiology at large-scales across the critical boreal regions.

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

    KAUST Repository

    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.

    2015-01-01

    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.

  9. 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.

  10. Resistivity variations related to the large March 9, 1998 eruption at La Fournaise volcano inferred by continuous MT monitoring

    Science.gov (United States)

    Wawrzyniak, Pierre; Zlotnicki, Jacques; Sailhac, Pascal; Marquis, Guy

    2017-11-01

    The 2645 m-high La Fournaise volcano, located in the Southwest of Réunion Island (Indian Ocean), is a shield basaltic volcano where effusive eruptions generally occur along long fissures starting from the summit, alongside major fractures that characterize the eruptions' dynamism and effusivity. Between 1992 and 1998, the volcano underwent a quiet period during which few earthquakes were recorded. Minor seismic activity returned after 1997 and picked up in March 1998 during the 35 h preceding the March 9 eruption. From 1996, two autonomous stations (CSV and BAV) were installed on the volcano. CSV was located inside the Enclos Fouqué caldera while BAV was positioned 8.2 km NW of the volcano summit. Horizontal components of the electric and magnetic fields were sampled every 20 s. Continuous time-series were available from 1996 to 1999 at CSV, and from 1997 to March 1998 at BAV. Data have been processed using both single-station and remote-reference processing. Both results show apparent resistivity variations synchronous to the eruption. Time-lapse impedance estimates are computed on overlapping time windows of about two days at both stations. The only major decrease of the observed impedance coincides with the March 1998 eruption. At CSV, the resistivity started to drop about five days before the eruption, reached several local minima until April, and then slowly increased as the volcanic crisis reduced in activity. After the end of the crisis in September 1998, the apparent resistivity recovered its pre-crisis value. The time-lapse results also show variability in directionality: sharp and elongated phase tensor ellipse residuals appear during the eruption with a N105° orientation, suggesting the emergence of an almost NS-striking dyke. A 1D background model built from MT soundings performed during the quiet period (1996 to February 1998) on which a 3D NS-striking dyke was added shows a good agreement with phase tensor residuals and spatial distribution of the

  11. Topological variation in single-gene phylogenetic trees

    OpenAIRE

    Castresana, Jose

    2007-01-01

    A recent large-scale phylogenomic study has shown the great degree of topological variation that can be found among eukaryotic phylogenetic trees constructed from single genes, highlighting the problems that can be associated with gene sampling in phylogenetic studies.

  12. Annual and semiannual variations in the ionospheric F2-layer: II. Physical discussion

    Directory of Open Access Journals (Sweden)

    H. Rishbeth

    2000-08-01

    Full Text Available The companion paper by Zou et al. shows that the annual and semiannual variations in the peak F2-layer electron density (NmF2 at midlatitudes can be reproduced by a coupled thermosphere-ionosphere computational model (CTIP, without recourse to external influences such as the solar wind, or waves and tides originating in the lower atmosphere. The present work discusses the physics in greater detail. It shows that noon NmF2 is closely related to the ambient atomic/molecular concentration ratio, and suggests that the variations of NmF2 with geographic and magnetic longitude are largely due to the geometry of the auroral ovals. It also concludes that electric fields play no important part in the dynamics of the midlatitude thermosphere. Our modelling leads to the following picture of the global three-dimensional thermospheric circulation which, as envisaged by Duncan, is the key to explaining the F2-layer variations. At solstice, the almost continuous solar input at high summer latitudes drives a prevailing summer-to-winter wind, with upwelling at low latitudes and throughout most of the summer hemisphere, and a zone of downwelling in the winter hemisphere, just equatorward of the auroral oval. These motions affect thermospheric composition more than do the alternating day/night (up-and-down motions at equinox. As a result, the thermosphere as a whole is more molecular at solstice than at equinox. Taken in conjunction with the well-known relation of F2-layer electron density to the atomic/molecular ratio in the neutral air, this explains the F2-layer semiannual effect in NmF2 that prevails at low and middle latitudes. At higher midlatitudes, the seasonal behaviour depends on the geographic latitude of the winter downwelling zone, though the effect of the composition changes is modified by the large solar zenith angle at midwinter. The zenith angle effect is especially important in longitudes far from the magnetic poles. Here, the downwelling occurs

  13. Sequential decoders for large MIMO systems

    KAUST Repository

    Ali, Konpal S.

    2014-05-01

    Due to their ability to provide high data rates, multiple-input multiple-output (MIMO) systems have become increasingly popular. Decoding of these systems with acceptable error performance is computationally very demanding. In this paper, we employ the Sequential Decoder using the Fano Algorithm for large MIMO systems. A parameter called the bias is varied to attain different performance-complexity trade-offs. Low values of the bias result in excellent performance but at the expense of high complexity and vice versa for higher bias values. Numerical results are done that show moderate bias values result in a decent performance-complexity trade-off. We also attempt to bound the error by bounding the bias, using the minimum distance of a lattice. The variations in complexity with SNR have an interesting trend that shows room for considerable improvement. Our work is compared against linear decoders (LDs) aided with Element-based Lattice Reduction (ELR) and Complex Lenstra-Lenstra-Lovasz (CLLL) reduction. © 2014 IFIP.

  14. Large variations in ocular dimensions in a multiethnic population with similar genetic background

    OpenAIRE

    Niu, Zhiqiang; Li, Jun; Zhong, Hua; Yuan, Zhonghua; Zhou, Hua; Zhang, Yang; Yuan, Yuansheng; Chen, Qin; Pan, Chen-Wei

    2016-01-01

    We aimed to describe the ethnic variations in ocular dimensions among three ethnic groups with similar genetic ancestry from mainland of China. We included 2119 ethnic Bai, 2202 ethnic Yi and 2183 ethnic Han adults aged 50 years or older in the study. Ocular dimensions including axial length (AL), anterior chamber depth (ACD), vitreous chamber depth (VCD) and lens thickness (LT) were measured using A-scan ultrasonography. Bai Chinese had longer ALs (P?

  15. Climatological changing effects on wind, precipitation and erosion: Large, meso and small scale analysis

    International Nuclear Information System (INIS)

    Aslan, Z.

    2004-01-01

    The Fourier transformation analysis for monthly average values of meteorological parameters has been considered, and amplitudes, phase angles have been calculated by using ground measurements in Turkey. The first order harmonics of meteorological parameters show large scale effects, while higher order harmonics show the effects of small scale fluctuations. The variations of first through sixth order harmonic amplitudes and phases provide a useful means of understanding the large and local scale effects on meteorological parameters. The phase angle can be used to determine the time of year the maximum or minimum of a given harmonic occurs. The analysis helps us to distinguish different pressure, relative humidity, temperature, precipitation and wind speed regimes and transition regions. Local and large scale phenomenon and some unusual seasonal patterns are also defined near Keban Dam and the irrigation area. Analysis of precipitation based on long term data shows that semi-annual fluctuations are predominant in the study area. Similarly, pressure variations are mostly influenced by semi-annual fluctuations. Temperature and humidity variations are mostly influenced by meso and micro scale fluctuations. Many large and meso scale climate change simulations for the 21st century are based on concentration of green house gases. A better understanding of these effects on soil erosion is necessary to determine social, economic and other impacts of erosion. The second part of this study covers the time series analysis of precipitation, rainfall erosivity and wind erosion at the Marmara Region. Rainfall and runoff erosivity factors are defined by considering the results of field measurements at 10 stations. Climatological changing effects on rainfall erosion have been determined by monitoring meteorological variables. In the previous studies, Fournier Index is defined to estimate the rainfall erosivity for the study area. The Fournier Index or in other words a climatic index

  16. Unscheduled load flow effect due to large variation in the distributed generation in a subtransmission network

    Science.gov (United States)

    Islam, Mujahidul

    A sustainable energy delivery infrastructure implies the safe and reliable accommodation of large scale penetration of renewable sources in the power grid. In this dissertation it is assumed there will be no significant change in the power transmission and distribution structure currently in place; except in the operating strategy and regulatory policy. That is to say, with the same old structure, the path towards unveiling a high penetration of switching power converters in the power system will be challenging. Some of the dimensions of this challenge are power quality degradation, frequent false trips due to power system imbalance, and losses due to a large neutral current. The ultimate result is the reduced life of many power distribution components - transformers, switches and sophisticated loads. Numerous ancillary services are being developed and offered by the utility operators to mitigate these problems. These services will likely raise the system's operational cost, not only from the utility operators' end, but also reflected on the Independent System Operators and by the Regional Transmission Operators (RTO) due to an unforeseen backlash of frequent variation in the load-side generation or distributed generation. The North American transmission grid is an interconnected system similar to a large electrical circuit. This circuit was not planned but designed over 100 years. The natural laws of physics govern the power flow among loads and generators except where control mechanisms are installed. The control mechanism has not matured enough to withstand the high penetration of variable generators at uncontrolled distribution ends. Unlike a radial distribution system, mesh or loop networks can alleviate complex channels for real and reactive power flow. Significant variation in real power injection and absorption on the distribution side can emerge as a bias signal on the routing reactive power in some physical links or channels that are not distinguishable

  17. Temporal and spatial variations of soil carbon dioxide, methane, and nitrous oxide fluxes in a Southeast Asian tropical rainforest

    Science.gov (United States)

    Itoh, M.; Kosugi, Y.; Takanashi, S.; Hayashi, Y.; Kanemitsu, S.; Osaka, K.; Tani, M.; Nik, A. R.

    2010-09-01

    To clarify the factors controlling temporal and spatial variations of soil carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes, we investigated these gas fluxes and environmental factors in a tropical rainforest in Peninsular Malaysia. Temporal variation of CO2 flux in a 2-ha plot was positively related to soil water condition and rainfall history. Spatially, CO2 flux was negatively related to soil water condition. When CO2 flux hotspots were included, no other environmental factors such as soil C or N concentrations showed any significant correlation. Although the larger area sampled in the present study complicates explanations of spatial variation of CO2 flux, our results support a previously reported bipolar relationship between the temporal and spatial patterns of CO2 flux and soil water condition observed at the study site in a smaller study plot. Flux of CH4 was usually negative with little variation, resulting in the soil at our study site functioning as a CH4 sink. Both temporal and spatial variations of CH4 flux were positively related to the soil water condition. Soil N concentration was also related to the spatial distribution of CH4 flux. Some hotspots were observed, probably due to CH4 production by termites, and these hotspots obscured the relationship between both temporal and spatial variations of CH4 flux and environmental factors. Temporal variation of N2O flux and soil N2O concentration was large and significantly related to the soil water condition, or in a strict sense, to rainfall history. Thus, the rainfall pattern controlled wet season N2O production in soil and its soil surface flux. Spatially, large N2O emissions were detected in wet periods at wetter and anaerobic locations, and were thus determined by soil physical properties. Our results showed that, even in Southeast Asian rainforests where distinct dry and wet seasons do not exist, variation in the soil water condition related to rainfall history controlled the

  18. Large trees drive forest aboveground biomass variation in moist lowland forests across the tropics

    NARCIS (Netherlands)

    Slik, J.W.F.; Paoli, G.; McGuire, K.; Amaral, I.; Barroso, J.; Bongers, F.; Poorter, L.

    2013-01-01

    Aim - Large trees (d.b.h.¿=¿70¿cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, potentially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore

  19. Large scale study on the variation of RF energy absorption in the head and brain regions of adults and children and evaluation of the SAM phantom conservativeness

    International Nuclear Information System (INIS)

    Keshvari, J; Kivento, M; Christ, A; Bit-Babik, G

    2016-01-01

    This paper presents the results of two computational large scale studies using highly realistic exposure scenarios, MRI based human head and hand models, and two mobile phone models. The objectives are (i) to study the relevance of age when people are exposed to RF by comparing adult and child heads and (ii) to analyze and discuss the conservativeness of the SAM phantom for all age groups. Representative use conditions were simulated using detailed CAD models of two mobile phones operating between 900 MHz and 1950 MHz including configurations with the hand holding the phone, which were not considered in most previous studies. The peak spatial-average specific absorption rate (psSAR) in the head and the pinna tissues is assessed using anatomically accurate head and hand models. The first of the two mentioned studies involved nine head-, four hand- and two phone-models, the second study included six head-, four hand- and three simplified phone-models (over 400 configurations in total). In addition, both studies also evaluated the exposure using the SAM phantom. Results show no systematic differences between psSAR induced in the adult and child heads. The exposure level and its variation for different age groups may be different for particular phones, but no correlation between psSAR and model age was found. The psSAR from all exposure conditions was compared to the corresponding configurations using SAM, which was found to be conservative in the large majority of cases. (paper)

  20. Atmospheric pressure, density, temperature and wind variations between 50 and 200 km

    Science.gov (United States)

    Justus, C. G.; Woodrum, A.

    1972-01-01

    Data on atmospheric pressure, density, temperature and winds between 50 and 200 km were collected from sources including Meteorological Rocket Network data, ROBIN falling sphere data, grenade release and pitot tube data, meteor winds, chemical release winds, satellite data, and others. These data were analyzed by a daily difference method and results on the distribution statistics, magnitude, and spatial structure of the irregular atmospheric variations are presented. Time structures of the irregular variations were determined by the analysis of residuals from harmonic analysis of time series data. The observed height variations of irregular winds and densities are found to be in accord with a theoretical relation between these two quantities. The latitude variations (at 50 - 60 km height) show an increasing trend with latitude. A possible explanation of the unusually large irregular wind magnitudes of the White Sands MRN data is given in terms of mountain wave generation by the Sierra Nevada range about 1000 km west of White Sands. An analytical method is developed which, based on an analogy of the irregular motion field with axisymmetric turbulence, allows measured or model correlation or structure functions to be used to evaluate the effective frequency spectra of scalar and vector quantities of a spacecraft moving at any speed and at any trajectory elevation angle.

  1. Y-Chromosome variation in hominids: intraspecific variation is limited to the polygamous chimpanzee.

    Directory of Open Access Journals (Sweden)

    Gabriele Greve

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

  2. Variations in Financial Performance among Peer Groups of Critical Access Hospitals

    Science.gov (United States)

    Pink, George H.; Holmes, George M.; Thompson, Roger E.; Slifkin, Rebecca T.

    2007-01-01

    Context: Among the large number of hospitals with critical access hospital (CAH) designation, there is substantial variation in facility revenue as well as the number and types of services provided. If these variations have material effects on financial indicators, then performance comparisons among all CAHs are problematic. Purpose: To…

  3. An Easy Way to Show Memory Color Effects.

    Science.gov (United States)

    Witzel, Christoph

    2016-01-01

    This study proposes and evaluates a simple stimulus display that allows one to measure memory color effects (the effect of object knowledge and memory on color perception). The proposed approach is fast and easy and does not require running an extensive experiment. It shows that memory color effects are robust to minor variations due to a lack of color calibration.

  4. An Easy Way to Show Memory Color Effects

    OpenAIRE

    Witzel, Christoph

    2016-01-01

    This study proposes and evaluates a simple stimulus display that allows one to measure memory color effects (the effect of object knowledge and memory on color perception). The proposed approach is fast and easy and does not require running an extensive experiment. It shows that memory color effects are robust to minor variations due to a lack of color calibration.

  5. Risk Aversion in Game Shows

    DEFF Research Database (Denmark)

    Andersen, Steffen; Harrison, Glenn W.; Lau, Morten I.

    2008-01-01

    We review the use of behavior from television game shows to infer risk attitudes. These shows provide evidence when contestants are making decisions over very large stakes, and in a replicated, structured way. Inferences are generally confounded by the subjective assessment of skill in some games......, and the dynamic nature of the task in most games. We consider the game shows Card Sharks, Jeopardy!, Lingo, and finally Deal Or No Deal. We provide a detailed case study of the analyses of Deal Or No Deal, since it is suitable for inference about risk attitudes and has attracted considerable attention....

  6. Explaining mutualism variation: a new evolutionary paradox?

    Science.gov (United States)

    Heath, Katy D; Stinchcombe, John R

    2014-02-01

    The paradox of mutualism is typically framed as the persistence of interspecific cooperation, despite the potential advantages of cheating. Thus, mutualism research has tended to focus on stabilizing mechanisms that prevent the invasion of low-quality partners. These mechanisms alone cannot explain the persistence of variation for partner quality observed in nature, leaving a large gap in our understanding of how mutualisms evolve. Studying partner quality variation is necessary for applying genetically explicit models to predict evolution in natural populations, a necessary step for understanding the origins of mutualisms as well as their ongoing dynamics. An evolutionary genetic approach, which is focused on naturally occurring mutualist variation, can potentially synthesize the currently disconnected fields of mutualism evolution and coevolutionary genetics. We outline explanations for the maintenance of genetic variation for mutualism and suggest approaches necessary to address them. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  7. Estimation of physical activity levels using cell phone questionnaires: a comparison with accelerometry for evaluation of between-subject and within-subject variations.

    Science.gov (United States)

    Bexelius, Christin; Sandin, Sven; Trolle Lagerros, Ylva; Litton, Jan-Eric; Löf, Marie

    2011-09-25

    Physical activity promotes health and longevity. Further elaboration of the role of physical activity for human health in epidemiological studies on large samples requires accurate methods that are easy to use, cheap, and possible to repeat. The use of telecommunication technologies such as cell phones is highly interesting in this respect. In an earlier report, we showed that physical activity level (PAL) assessed using a cell phone procedure agreed well with corresponding estimates obtained using the doubly labeled water method. However, our earlier study indicated high within-subject variation in relation to between-subject variations in PAL using cell phones, but we could not assess if this was a true variation of PAL or an artifact of the cell phone technique. Our objective was to compare within- and between-subject variations in PAL by means of cell phones with corresponding estimates using an accelerometer. In addition, we compared the agreement of daily PAL values obtained using the cell phone questionnaire with corresponding data obtained using an accelerometer. PAL was measured both with the cell phone questionnaire and with a triaxial accelerometer daily during a 2-week study period in 21 healthy Swedish women (20 to 45 years of age and BMI from 17.7 kg/m² to 33.6 kg/m²). The results were evaluated by fitting linear mixed effect models and descriptive statistics and graphs. With the accelerometer, 57% (95% confidence interval [CI] 40%-66%) of the variation was within subjects, while with the cell phone, within-subject variation was 76% (95% CI 59%-83%). The day-to-day variations in PAL observed using the cell phone questions agreed well with the corresponding accelerometer results. Both the cell phone questionnaire and the accelerometer showed high within-subject variations. Furthermore, day-to-day variations in PAL within subjects assessed using the cell phone agreed well with corresponding accelerometer values. Consequently, our cell phone

  8. A parametric method for assessing diversification-rate variation in phylogenetic trees.

    Science.gov (United States)

    Shah, Premal; Fitzpatrick, Benjamin M; Fordyce, James A

    2013-02-01

    Phylogenetic hypotheses are frequently used to examine variation in rates of diversification across the history of a group. Patterns of diversification-rate variation can be used to infer underlying ecological and evolutionary processes responsible for patterns of cladogenesis. Most existing methods examine rate variation through time. Methods for examining differences in diversification among groups are more limited. Here, we present a new method, parametric rate comparison (PRC), that explicitly compares diversification rates among lineages in a tree using a variety of standard statistical distributions. PRC can identify subclades of the tree where diversification rates are at variance with the remainder of the tree. A randomization test can be used to evaluate how often such variance would appear by chance alone. The method also allows for comparison of diversification rate among a priori defined groups. Further, the application of the PRC method is not restricted to monophyletic groups. We examined the performance of PRC using simulated data, which showed that PRC has acceptable false-positive rates and statistical power to detect rate variation. We apply the PRC method to the well-studied radiation of North American Plethodon salamanders, and support the inference that the large-bodied Plethodon glutinosus clade has a higher historical rate of diversification compared to other Plethodon salamanders. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  9. Big bees do a better job: intraspecific size variation influences pollination effectiveness

    Directory of Open Access Journals (Sweden)

    Pat Willmer

    2014-09-01

    Full Text Available 1. Bumblebees (Bombus spp. are efficient pollinators of many flowering plants, yet the pollen deposition performance of individual bees has not been investigated. Worker bumblebees exhibit large intraspecific and intra-nest size variation, in contrast with other eusocial bees; and their size influences collection and deposition of pollen grains. 2. Laboratory studies with B. terrestris workers and Vinca minor flowers showed that pollination effectiveness PE, as measured from pollen grains deposited on stigmas in single visits (SVD, was significantly positively related to bee size; larger bees deposited more grains, while the smallest individuals, with proportionally shorter tongues, were unable to collect or deposit pollen in these flowers. Individuals did not increase their pollen deposition over time, so handling experience does not influence SVD in Vinca minor. 3. Field studies using Geranium sanguineum and Echium vulgare, and multiple visiting species, confirmed that individual size affects SVD. All bumblebee species showed positive SVD/size effects, though even the smallest individuals did deposit pollen. Apis with its limited size variation showed no such detectable effect when visiting Geranium flowers. Two abundant hoverfly species also showed size effects, particularly when feeding for nectar on Echium. 4. Mean size of foragers also varied diurnally, with larger individuals active earlier and later, so that pollination effectiveness varies through a day; flowers routinely pollinated by bees may best be served by early morning dehiscence and visits from larger individuals. 5. Thus, while there are well-documented species-level variations in pollination effectiveness, the fine-scale individual differences between foragers should also be taken into account when assessing the reproductive outputs of biotically-pollinated plants.

  10. Cognitive ability correlates positively with son birth and predicts cross-cultural variation of the offspring sex ratio

    Science.gov (United States)

    Dama, Madhukar Shivajirao

    2013-06-01

    Human populations show remarkable variation in the sex ratio at birth which is believed to be related to the parental condition. In the present study, the global variation of sex ratio at birth (SRB, proportion of male offspring born) was analyzed with respect to indirect measure of condition, the intelligence quotient (IQ). IQ correlates strongly with lifespan across nations, which makes it a good indicator of health of the large populations. Relation between three standard measures of average national IQ and SRB was studied using multiple linear regression models. Average national IQ was positively correlated with SRB ( r = 0.54 to 0.57, p difference in general condition of populations.

  11. Amplitude Variations in Pulsating Red Giants. II. Some Systematics

    Science.gov (United States)

    Percy, J. R.; Laing, J.

    2017-12-01

    In order to extend our previous studies of the unexplained phenomenon of cyclic amplitude variations in pulsating red giants, we have used the AAVSO time-series analysis package vstar to analyze long-term AAVSO visual observations of 50 such stars, mostly Mira stars. The relative amount of the variation, typically a factor of 1.5, and the time scale of the variation, typically 20-35 pulsation periods, are not significantly different in longer-period, shorter-period, and carbon stars in our sample, and they also occur in stars whose period is changing secularly, perhaps due to a thermal pulse. The time scale of the variations is similar to that in smaller-amplitude SR variables, but the relative amount of the variation appears to be larger in smaller-amplitude stars, and is therefore more conspicuous. The cause of the amplitude variations remains unclear, though they may be due to rotational modulation of a star whose pulsating surface is dominated by the effects of large convective cells.

  12. Investigation on seasonal variation of thermal-induced strain in flexible pavements based on field and laboratory measurements

    Directory of Open Access Journals (Sweden)

    Simita Biswas

    2016-09-01

    Full Text Available Pavement temperature variation has a large influence on the structural response of flexible pavements. Daily and seasonal temperature fluctuation causes expansion and contraction of pavement material, which then leads to the generation of thermal strain. In this study, field observation and laboratory tests were conducted to investigate seasonal variation of thermal-induced strain in flexible pavement. Field observations were conducted at the Integrated Road Research Facility (IRRF’s test road in Edmonton, Alberta, Canada, which is fully equipped with structural and environmental monitoring instruments. The main objective of the field study was to compare the variation of thermal-induced strain in warm and cold seasons. Field results indicated that thermal-induced strain is 1.4–2.0 times greater in cold seasons than in warm seasons following the same pavement temperature variations; however, strain generation rate was greater in warm seasons. Laboratory testing of asphalt slab and cylindrical samples produced comparable ratios. Moreover, field observation and laboratory testing showed a similar trend of temperature and thermal strain variations. Keywords: Thermal-induced strain, Asphalt strain gauge, Field observation, Flexible pavement, Laboratory testing, Seasonal variation

  13. Genetically-based olfactory signatures persist despite dietary variation.

    Directory of Open Access Journals (Sweden)

    Jae Kwak

    Full Text Available Individual mice have a unique odor, or odortype, that facilitates individual recognition. Odortypes, like other phenotypes, can be influenced by genetic and environmental variation. The genetic influence derives in part from genes of the major histocompatibility complex (MHC. A major environmental influence is diet, which could obscure the genetic contribution to odortype. Because odortype stability is a prerequisite for individual recognition under normal behavioral conditions, we investigated whether MHC-determined urinary odortypes of inbred mice can be identified in the face of large diet-induced variation. Mice trained to discriminate urines from panels of mice that differed both in diet and MHC type found the diet odor more salient in generalization trials. Nevertheless, when mice were trained to discriminate mice with only MHC differences (but on the same diet, they recognized the MHC difference when tested with urines from mice on a different diet. This indicates that MHC odor profiles remain despite large dietary variation. Chemical analyses of urinary volatile organic compounds (VOCs extracted by solid phase microextraction (SPME and analyzed by gas chromatography/mass spectrometry (GC/MS are consistent with this inference. Although diet influenced VOC variation more than MHC, with algorithmic training (supervised classification MHC types could be accurately discriminated across different diets. Thus, although there are clear diet effects on urinary volatile profiles, they do not obscure MHC effects.

  14. Variational principles for locally variational forms

    International Nuclear Information System (INIS)

    Brajercik, J.; Krupka, D.

    2005-01-01

    We present the theory of higher order local variational principles in fibered manifolds, in which the fundamental global concept is a locally variational dynamical form. Any two Lepage forms, defining a local variational principle for this form, differ on intersection of their domains, by a variationally trivial form. In this sense, but in a different geometric setting, the local variational principles satisfy analogous properties as the variational functionals of the Chern-Simons type. The resulting theory of extremals and symmetries extends the first order theories of the Lagrange-Souriau form, presented by Grigore and Popp, and closed equivalents of the first order Euler-Lagrange forms of Hakova and Krupkova. Conceptually, our approach differs from Prieto, who uses the Poincare-Cartan forms, which do not have higher order global analogues

  15. A Modified Alternating Direction Method for Variational Inequality Problems

    International Nuclear Information System (INIS)

    Han, D.

    2002-01-01

    The alternating direction method is an attractive method for solving large-scale variational inequality problems whenever the subproblems can be solved efficiently. However, the subproblems are still variational inequality problems, which are as structurally difficult to solve as the original one. To overcome this disadvantage, in this paper we propose a new alternating direction method for solving a class of nonlinear monotone variational inequality problems. In each iteration the method just makes an orthogonal projection to a simple set and some function evaluations. We report some preliminary computational results to illustrate the efficiency of the method

  16. Seasonal variations of U.S. mortality rates: Roles of solar ultraviolet-B doses, vitamin D, gene exp ression, and infections.

    Science.gov (United States)

    Grant, William B; Bhattoa, Harjit Pal; Boucher, Barbara J

    2017-10-01

    Death rates in the U.S. show a pronounced seasonality. The broad seasonal variation shows about 25% higher death rates in winter than in summer with an additional few percent increase associated with the Christmas and New Year's holidays. A pronounced increase in death rates also starts in mid-September, shortly after the school year begins. The causes of death with large contributions to the observed seasonality include diseases of the circulatory system; the respiratory system; the digestive system; and endocrine, nutritional, and metabolic diseases. Researchers have identified several factors showing seasonal variation that could possibly explain the seasonal variations in mortality rate. These factors include seasonal variations in solar ultraviolet-B(UVB) doses and serum 25-hydroxyvitamin D [25(OH)D] concentrations, gene expression, ambient temperature and humidity, UVB effects on environmental pathogen load, environmental pollutants and allergens, and photoperiod (or length of day). The factors with the strongest support in this analysis are seasonal variations in solar UVB doses and 25(OH)D concentrations. In the U.S., population mean 25(OH)D concentrations range from 21ng/mL in March to 28ng/mL in August. Measures to ensure that all people had 25(OH)D concentrations >36ng/mL year round would probably reduce death rates significantly. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Study of steady-state heat transfer with various large beam intensities in ADS windowless spallation target

    International Nuclear Information System (INIS)

    Liu, Jie; Gao, Lei; Tong, Jian-fei; Mehmood, Irfan; Lu, Wen-qiang

    2015-01-01

    Thermal hydraulics of spallation target, which is regarded as the ‘heart’ of the accelerator driven system (ADS), is very complicated due to the flow of the heavy liquid metal, spallation reaction and the coupling. In this paper, the steady-state temperature distribution, based on the flow pattern and the heat deposition, in the windowless spallation target with various large beam intensities from 10 mA to 40 mA is obtained to be in line with the development of ADS in China. The results show that the shape of temperature distribution is the same as broken wing of the butterfly but the temperature gradient and the maximum temperature vary in proportion with beam intensity. The variation of temperature gradient in different zones is also used to figure out the effect of large beam intensity. It has been found that large radial and axial temperature gradient leads to large temperature gradient on the wall. This may cause extremely large thermal stresses which leads to structural material damage. The results may be applied to the future design and optimization of ADS in China. - Highlights: • Shape of temperature distribution is the same but temperature gradient and maximum temperature vary with intensity. • The variation of temperature gradient in different zones reveals the effect of large beam intensity. • Large radial and axial temperature gradient leads to large temperature gradient on the wall

  18. Velocity variations associated with the large 2010 eruption of Merapi volcano, Java, retrieved from seismic multiplets and ambient noise cross-correlation

    Science.gov (United States)

    Budi-Santoso, Agus; Lesage, Philippe

    2016-07-01

    We present a study of the seismic velocity variations that occurred in the structure before the large 2010 eruption of Merapi volcano. For the first time to our knowledge, the technique of coda wave interferometry is applied to both families of similar events (multiplets) and to correlation functions of seismic noise. About half of the seismic events recorded at the summit stations belong to one of the ten multiplets identified, including 120 similar events that occurred in the last 20 hr preceding the eruption onset. Daily noise cross-correlation functions (NCF) were calculated for the six pairs of short-period stations available. Using the stretching method, we estimate time-series of apparent velocity variation (AVV) for each multiplet and each pair of stations. No significant velocity change is detected until September 2010. From 10 October to the beginning of the eruption on 26 October, a complex pattern of AVV is observed with amplitude of up to ±1.5 per cent. Velocity decrease is first observed from families of deep events and then from shallow earthquakes. In the same period, AVV with different signs and chronologies are estimated from NCF calculated for various station pairs. The location in the horizontal plane of the velocity perturbations related with the AVV obtained from NCF is estimated by using an approach based on the radiative transfer approximation. Although their spatial resolution is limited, the resulting maps display velocity decrease in the upper part of the edifice in the period 12-25 October. After the eruption onset, the pattern of velocity perturbations is significantly modified with respect to the previous one. We interpret these velocity variations in the framework of a scenario of magmatic intrusion that integrates most observations. The perturbation of the stress field associated with the magma migration can induce both decrease and increase of the seismic velocity of rocks. Thus the detected AVVs can be considered as precursors of

  19. Spanwise drag variation on low Re wings -- revisited

    Science.gov (United States)

    Yang, Shanling; Spedding, Geoffrey

    2011-11-01

    Aerodynamic performance measurement and prediction of airfoils and wings at chord Reynolds numbers below 105 is both difficult and increasingly important in application to small-scale aircraft. Not only are the aerodynamics strongly affected by the dynamics of the unstable laminar boundary layer but the flow is decreasingly likely to be two-dimensional as Re decreases. The spanwise variation of the flow along a two-dimensional geometry is often held to be responsible for the large variations in measured profile drag coefficient. Here we measure local two-dimensional drag coefficients along a finite wing using non-intrusive PIV methods. Variations in Cd (y) can be related to local flow variations on the wing itself. Integrated values can be compared with force balance data, and the proper description of drag components at low Re will be discussed.

  20. Geographic variation in expenditures for workers' compensation physician claims.

    Science.gov (United States)

    Miller, T R; Levy, D T

    1997-07-01

    We examine interstate variations in the cost of claims for physician care using injury claims from Worker's Compensation, and consider some of the factors that may explain cost differences. Multivariate regression analysis is used to isolate state variations, while controlling for personal and injury characteristics, and state characteristics. Statistical analyses reveal considerable variation in expenditures for physician care of injuries across states, even after controlling for case mix and state characteristics. We also find that the presence of HMOs and of general practitioners as a percent of physicians are associated with lower claims, and that the percent of the state that is urban is associated with higher claims. The large variation in costs suggests a potential to affect the costs of physician care for work-related injuries.

  1. The interannual precipitation variability in the southern part of Iran as linked to large-scale climate modes

    Energy Technology Data Exchange (ETDEWEB)

    Pourasghar, Farnaz; Jahanbakhsh, Saeed; Sari Sarraf, Behrooz [The University of Tabriz, Department of Physical Geography, Faculty of Humanities and Social Science, Tabriz (Iran, Islamic Republic of); Tozuka, Tomoki [The University of Tokyo, Department of Earth and Planetary Science, Graduate School of Science, Tokyo (Japan); Ghaemi, Hooshang [Iran Meteorological Organization, Tehran (Iran, Islamic Republic of); Yamagata, Toshio [The University of Tokyo, Department of Earth and Planetary Science, Graduate School of Science, Tokyo (Japan); Application Laboratory/JAMSTEC, Yokohama, Kanagawa (Japan)

    2012-11-15

    The interannual variation of precipitation in the southern part of Iran and its link with the large-scale climate modes are examined using monthly data from 183 meteorological stations during 1974-2005. The majority of precipitation occurs during the rainy season from October to May. The interannual variation in fall and early winter during the first part of the rainy season shows apparently a significant positive correlation with the Indian Ocean Dipole (IOD) and El Nino-Southern Oscillation (ENSO). However, a partial correlation analysis used to extract the respective influence of IOD and ENSO shows a significant positive correlation only with the IOD and not with ENSO. The southeasterly moisture flux anomaly over the Arabian Sea turns anti-cyclonically and transport more moisture to the southern part of Iran from the Arabian Sea, the Red Sea, and the Persian Gulf during the positive IOD. On the other hand, the moisture flux has northerly anomaly over Iran during the negative IOD, which results in reduced moisture supply from the south. During the latter part of the rainy season in late winter and spring, the interannual variation of precipitation is more strongly influenced by modes of variability over the Mediterranean Sea. The induced large-scale atmospheric circulation anomaly controls moisture supply from the Red Sea and the Persian Gulf. (orig.)

  2. Poloidal variation of viscous forces in the banana collisionality regime

    International Nuclear Information System (INIS)

    Wang, J.P.; Callen, J.D.

    1992-12-01

    The poloidal variation of the parallel viscous and heat viscous forces are determined for the first time using a rigorous Chapman- Enskog-like approach that has been developed recently. It is shown that the poloidal variation is approximately proportional to the poloidal distribution of the trapped particles, which are concentrated on the outer edge (large major radius side) of the tokamak

  3. Functional variation in the gut microbiome of wild Drosophila populations.

    Science.gov (United States)

    Bost, Alyssa; Martinson, Vincent G; Franzenburg, Soeren; Adair, Karen L; Albasi, Alice; Wells, Martin T; Douglas, Angela E

    2018-05-26

    Most of the evidence that the gut microbiome of animals is functionally variable, with consequences for the health and fitness of the animal host, is based on laboratory studies, often using inbred animals under tightly controlled conditions. It is largely unknown whether these microbiome effects would be evident in outbred animal populations under natural conditions. In this study, we quantified the functional traits of the gut microbiota (metagenome) and host (gut transcriptome) and the taxonomic composition of the gut microorganisms (16S rRNA gene sequence) in natural populations of three mycophagous Drosophila species. Variation in microbiome function and composition was driven principally by the period of sample collection, while host function varied mostly with Drosophila species, indicating that variation in microbiome traits is determined largely by environmental factors, and not host taxonomy. Despite this, significant correlations between microbiome and host functional traits were obtained. In particular, microbiome functions dominated by metabolism were positively associated with host functions relating to gut epithelial turnover. Much of the functional variation in the microbiome could be attributed to variation in abundance of Bacteroidetes, rather than the two other abundant groups, the γ-Proteobacteria or Lactobacillales. We conclude that functional variation in the interactions between animals and their gut microbiome can be detectable in natural populations and, in mycophagous Drosophila, this variation relates primarily to metabolism and homeostasis of the gut epithelium. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  4. Runoff and sediment variation in the areas with high and coarse sediment yield of the middle Yellow River

    Science.gov (United States)

    Zhang, Pan; Yao, Wenyi; Xiao, Peiqing; Sun, Weiying

    2018-02-01

    Massive water and soil conservation works (WSCW) have been conducted in the areas with high and coarse sediment yield of the middle Yellow River since 1982. With the impending effects of climate change, it is necessary to reconsider the effects of WSCW on runoff and sediment variation at decadal and regional scales. Using long-term official and synthesized data, the WSCW impacts on reducing water and soil loss were studied in Sanchuanhe River watershed. Results showed that the sediment and runoff generated from this area showed a decreasing trend in the past 50 years. A great progress has been achieved in erosion control since the 1970s. After the 4 soil and water conservation harnessing stages during the period from 1970 to 2006, the sediment and runoff yield showed decreases with the extension of harnessing. The results revealed that human activities exerted the largest effects on the sediment reduction and explained 66.6% of the variation in the specific sediment yield. The contribution of rainfall variation to runoff reduction was as large as human activities. A great benefit have been obtained in water and soil loss control in this area.

  5. Exploring subdomain variation in biomedical language

    Directory of Open Access Journals (Sweden)

    Séaghdha Diarmuid Ó

    2011-05-01

    Full Text Available Abstract Background Applications of Natural Language Processing (NLP technology to biomedical texts have generated significant interest in recent years. In this paper we identify and investigate the phenomenon of linguistic subdomain variation within the biomedical domain, i.e., the extent to which different subject areas of biomedicine are characterised by different linguistic behaviour. While variation at a coarser domain level such as between newswire and biomedical text is well-studied and known to affect the portability of NLP systems, we are the first to conduct an extensive investigation into more fine-grained levels of variation. Results Using the large OpenPMC text corpus, which spans the many subdomains of biomedicine, we investigate variation across a number of lexical, syntactic, semantic and discourse-related dimensions. These dimensions are chosen for their relevance to the performance of NLP systems. We use clustering techniques to analyse commonalities and distinctions among the subdomains. Conclusions We find that while patterns of inter-subdomain variation differ somewhat from one feature set to another, robust clusters can be identified that correspond to intuitive distinctions such as that between clinical and laboratory subjects. In particular, subdomains relating to genetics and molecular biology, which are the most common sources of material for training and evaluating biomedical NLP tools, are not representative of all biomedical subdomains. We conclude that an awareness of subdomain variation is important when considering the practical use of language processing applications by biomedical researchers.

  6. Variational principles and Heisenberg matrix mechanics

    International Nuclear Information System (INIS)

    Klein, A.; Li, C.-T.

    1979-01-01

    If in Heisenberg's equations of motion for a problem in quantum mechanics (or quantum field theory) one studies matrix elements in the energy representation and by use of completeness conditions expresses the equations solely in terms of matrix elements of the canonical variables, and if one does likewise with the associated kinematical constraints (commutation relations), one arrives at a formulation - largely unexplored hitherto - which can be exploited for both practical and theoretical development. In this contribution, the above theme is developed within the framework of one-dimensional problems. It is shown how this formulation, both dynamics and kinematics, can be derived from a new variational principle, indeed from an entire class of such principles. A powerful method of diagonalizing the Hamiltonians by means of computations utilizing these equations is described. The variational method is shown to be particularly useful for the study of the regime of large quantum numbers. The usual WKB approximation is seen to be contained as well as a basis for the study of systematic corrections to it. Further applications in progress are mentioned. (Auth.)

  7. Period variations in pulsating X-ray sources. I. Accretion flow parameters and neutron star structure from timing observations

    International Nuclear Information System (INIS)

    Lamb, F.K.; Pines, D.; Shaham, J.

    1978-01-01

    We show that valuable information about both accretion flows and neutron star structure can be obtained from X-ray timing observations of period variations in pulsating sources. Such variations can result from variations in the accretion flow, or from internal torque variations, associated with oscillations of the fluid core or the unpinning of vortices in the inner crust. We develop a statistical description of torque variations in terms of noise processes, indicate how the applicability of such a description may be tested observationally, and show how it may be used to determine from observation both the properties of accretion flows and the internal structure of neutron stars, including the relative inertial moments of the crust and superfluid neutron core, the crust-core coupling time, and the frequencies of any low-frequency internal collective modes. Particular attention is paid to the physical origin of spin-down episodes; it is shown that usyc episodes may result either from external torque reversals or from internal torque variations.With the aid of the statistical description, the response of the star to torque fluctuations is calculated for three stellar models: (i) a completely rigid star; (ii) a two-component star; and (iii) a two-component star with a finite-frequency internal mode, such as the Tkachenko mode of a rotating neutron superfluid. Our calculations show that fluctuating torques could account for the period the period variations and spin-down episodes observed in Her X-1 and Cen X-3, including the large spin-down event observed in the latter source during 1972 September-October. The torque noise strengths inferred from current timing observations using the simple two-component models are shown to be consistent with those to be expected from fluctuations in accretion flows onto magnetic neutron stars

  8. Genotypic Variation in Phosphorus Use Efficiency for Symbiotic Nitrogen Fixation in Cowpea (Vigna Unguiculata)

    Energy Technology Data Exchange (ETDEWEB)

    Andriamananjara, A. [LRI-SRA, Laboratoire des Radio-isotopes, Universite d' Antananarivo, Antananarivo (Madagascar); Abdou, M. Malam [Laboratoire Banques de genes CERRA / KOLLO, Institut National de Recherche Agronomique du Niger (INRAN), Niamey (Niger); Pernot, C.; Drevon, J. J. [Institut National de la Recherche Agronomique, UMR Eco and Sols, Montpellier (France)

    2013-11-15

    Cowpea (Vigna unguiculata L. Walp) is an important food legume. In Africa, it is mostly cultivated under such environmental constraints as drought and pest, and nutrient deficiency. In particular low soil phosphorus strongly limits crop production for the poor farmers with limited access to P fertilizers. Therefore breeding cowpea for the tolerance to P deficiency is considered as an alternative to increase the productivity of traditional cowpea-cereal cropping systems in soils with low P availability. This paper reports cowpea genotypic-variation in P use efficiency for symbiotic nitrogen fixation as a contribution to select tolerant cowpea lines under P deficiency. Eighty cowpea cultivars inoculated with the reference strain of Bradyrhizobium sp. Vigna CB756 were pre-screened as a single replicate under hydroaeroponic culture for 6 weeks under P deficiency versus P sufficiency, namely 15 vs 30 {mu}mol plant{sup -1} week{sup -1}. Large variability in nodule number per plant, and in shoot growth as a function of nodule mass, was observed among the diversity of cowpea lines. From this pre-screening experiment, the 40 cowpea lines showing the highest SNF-potential, i.e. high nodulation linked with high N{sub 2}-dependent growth under P sufficiency, and the most contrasting tolerance to P deficiency, i.e. highest vs lowest N{sub 2}-dependent growth under P deficiency, were grown again in glasshouse hydroaeroponics with 6 replicates. As an illustration of the most contrasting lines, the nodulation was decreased under P deficiency by less than 20% for IT82E-18 whereas by more than 80% for IT95K-1105-5 or SUVITA 2. The variations in nodulation were correlated with variations in growth with mean value of additional growth per unit increase in nodule biomass of 23 g shoot DW g-1 nodule DW under P sufficiency, showing 3 lines showing exceptionally high potential for symbiotic nitrogen fixation, versus 28 g shoot DW g{sup -1} nodule DW showing large variation among lines

  9. Inter-doctor variations in the assessment of functional incapacities by insurance physicians

    NARCIS (Netherlands)

    Schellart, A.J.; Mulders, H.; Steenbeek, R.; Anema, J.R.; Kroneman, H.; Besseling, J.

    2011-01-01

    Background. The aim of this study was to determine the - largely unexplored - extent of systematic variation in the work disability assessment by Dutch insurance physicians (IPs) of employees on long-term sick leave, and to ascertain whether this variation was associated with the individual

  10. Super-Planckian spatial field variations and quantum gravity

    Energy Technology Data Exchange (ETDEWEB)

    Klaewer, Daniel; Palti, Eran [Institut für Theoretische Physik, Ruprecht-Karls-Universität,Philosophenweg 19, 69120 Heidelberg (Germany)

    2017-01-20

    We study scenarios where a scalar field has a spatially varying vacuum expectation value such that the total field variation is super-Planckian. We focus on the case where the scalar field controls the coupling of a U(1) gauge field, which allows us to apply the Weak Gravity Conjecture to such configurations. We show that this leads to evidence for a conjectured property of quantum gravity that as a scalar field variation in field space asymptotes to infinity there must exist an infinite tower of states whose mass decreases as an exponential function of the scalar field variation. We determine the rate at which the mass of the states reaches this exponential behaviour showing that it occurs quickly after the field variation passes the Planck scale.

  11. Patterns of allozyme variation in diploid and tetraploid Centaurea jacea at different spatial scales.

    Science.gov (United States)

    Hardy, O J; Vekemans, X

    2001-05-01

    The extent and spatial patterns of genetic variation at allozyme markers were investigated within and between diploid and autotetraploid knapweeds (Centaurea jacea L. sensu lato, Asteraceae) at contrasted geographic scales: (1) among populations sampled from a diploid-tetraploid contact zone in the northeastern part of the Belgian Ardennes, and (2) within mixed populations from that zone where diploids and tetraploids coexist. Our data were also compared with a published dataset by Sommer (1990) describing allozyme variation in separate diploid and tetraploid knapweeds populations collected throughout Europe. Genetic diversity was higher in tetraploids. In the Belgian Ardennes and within the mixed populations, both cytotypes had similar levels of spatial genetic structure, they were genetically differentiated, and their distributions of allele frequencies were not spatially correlated. In contrast, at the European scale, diploids and tetraploids did not show differentiated gene pools and presented a strong correlation between their patterns of spatial genetic variation. Numerical simulations showed that the striking difference in patterns observed at small and large geographic scales could be accounted for by a combination of (1) isolation by distance within cytotypes; and (2) partial reproductive barriers between cytotypes and/or recurrent formation of tetraploids. We suggest that this may explain the difficulty of the taxonomic treatment of knapweeds and of polyploid complexes in general.

  12. Variation in gene expression within clones of the earthworm Dendrobaena octaedra.

    Directory of Open Access Journals (Sweden)

    Marina Mustonen

    Full Text Available Gene expression is highly plastic, which can help organisms to both acclimate and adapt to changing environments. Possible variation in gene expression among individuals with the same genotype (among clones is not widely considered, even though it could impact the results of studies that focus on gene expression phenotypes, for example studies using clonal lines. We examined the extent of within and between clone variation in gene expression in the earthworm Dendrobaena octaedra, which reproduces through apomictic parthenogenesis. Five microsatellite markers were developed and used to confirm that offspring are genetic clones of their parent. After that, expression of 12 genes was measured from five individuals each from six clonal lines after exposure to copper contaminated soil. Variation in gene expression was higher over all genotypes than within genotypes, as initially assumed. A subset of the genes was also examined in the offspring of exposed individuals in two of the clonal lines. In this case, variation in gene expression within genotypes was as high as that observed over all genotypes. One gene in particular (chymotrypsin inhibitor also showed significant differences in the expression levels among genetically identical individuals. Gene expression can vary considerably, and the extent of variation may depend on the genotypes and genes studied. Ensuring a large sample, with many different genotypes, is critical in studies comparing gene expression phenotypes. Researchers should be especially cautious inferring gene expression phenotypes when using only a single clonal or inbred line, since the results might be specific to only certain genotypes.

  13. The seasonal variation of radon concentration in the atmosphere of Chichi-jima island in the pacific ocean

    International Nuclear Information System (INIS)

    Yoshioka, Katsuhiro

    2008-01-01

    We continuously measured the radon concentration from April 2001 to December 2004 in Chichi-jima Is. We expect that the radon concentration at Chichi-jima Is. would be influenced only by the air mass transported through the long distance. The hourly values had very large variations, ranging from 0.2 to 6.0 Bqm -3 . No diurnal periodicity was found in the variation of the radon concentration. We found that the monthly averages of the radon concentration had a clear long term pattern, showing the highest in the winter and the lowest in the summer. To analyze the radon long time variation, an arriving air mass is grouped into five sectors according to the backward trajectory. Sector I is the sea areas surrounding Chichi-jima Is. Sector II including Philippines, Indonesia and the southeast Asia is spread the southwestern Pacific Ocean from Chichi-jima Is. and sector V is spread the northeastern way to the southeast. Sector III includes China, Mongolia, Korea and the western Japan region and sector IV two regions of the eastern Siberia and the eastern Japan. The radon long time variation showed a high positive correlation between the number of arrivals of the continental air mass, while strong negative correlation between the maritime air mass. (author)

  14. Feature discrimination/identification based upon SAR return variations

    Science.gov (United States)

    Rasco, W. A., Sr.; Pietsch, R.

    1978-01-01

    A study of the statistics of The look-to-look variation statistics in the returns recorded in-flight by a digital, realtime SAR system are analyzed. The determination that the variations in the look-to-look returns from different classes do carry information content unique to the classes was illustrated by a model based on four variants derived from four look in-flight SAR data under study. The model was limited to four classes of returns: mowed grass on a athletic field, rough unmowed grass and weeds on a large vacant field, young fruit trees in a large orchard, and metal mobile homes and storage buildings in a large mobile home park. The data population in excess of 1000 returns represented over 250 individual pixels from the four classes. The multivariant discriminant model operated on the set of returns for each pixel and assigned that pixel to one of the four classes, based on the target variants and the probability distribution function of the four variants for each class.

  15. Orion: Detecting regions of the human non-coding genome that are intolerant to variation using population genetics.

    Science.gov (United States)

    Gussow, Ayal B; Copeland, Brett R; Dhindsa, Ryan S; Wang, Quanli; Petrovski, Slavé; Majoros, William H; Allen, Andrew S; Goldstein, David B

    2017-01-01

    There is broad agreement that genetic mutations occurring outside of the protein-coding regions play a key role in human disease. Despite this consensus, we are not yet capable of discerning which portions of non-coding sequence are important in the context of human disease. Here, we present Orion, an approach that detects regions of the non-coding genome that are depleted of variation, suggesting that the regions are intolerant of mutations and subject to purifying selection in the human lineage. We show that Orion is highly correlated with known intolerant regions as well as regions that harbor putatively pathogenic variation. This approach provides a mechanism to identify pathogenic variation in the human non-coding genome and will have immediate utility in the diagnostic interpretation of patient genomes and in large case control studies using whole-genome sequences.

  16. Process variations in surface nano geometries manufacture on large area substrates

    DEFF Research Database (Denmark)

    Calaon, Matteo; Hansen, Hans Nørgaard; Tosello, Guido

    2014-01-01

    The need of transporting, treating and measuring increasingly smaller biomedical samples has pushed the integration of a far reaching number of nanofeatures over large substrates size in respect to the conventional processes working area windows. Dimensional stability of nano fabrication processe...

  17. Variational integrators for electric circuits

    International Nuclear Information System (INIS)

    Ober-Blöbaum, Sina; Tao, Molei; Cheng, Mulin; Owhadi, Houman; Marsden, Jerrold E.

    2013-01-01

    In this contribution, we develop a variational integrator for the simulation of (stochastic and multiscale) electric circuits. When considering the dynamics of an electric circuit, one is faced with three special situations: 1. The system involves external (control) forcing through external (controlled) voltage sources and resistors. 2. The system is constrained via the Kirchhoff current (KCL) and voltage laws (KVL). 3. The Lagrangian is degenerate. Based on a geometric setting, an appropriate variational formulation is presented to model the circuit from which the equations of motion are derived. A time-discrete variational formulation provides an iteration scheme for the simulation of the electric circuit. Dependent on the discretization, the intrinsic degeneracy of the system can be canceled for the discrete variational scheme. In this way, a variational integrator is constructed that gains several advantages compared to standard integration tools for circuits; in particular, a comparison to BDF methods (which are usually the method of choice for the simulation of electric circuits) shows that even for simple LCR circuits, a better energy behavior and frequency spectrum preservation can be observed using the developed variational integrator

  18. A variational Bayesian multiple particle filtering scheme for large-dimensional systems

    KAUST Repository

    Ait-El-Fquih, Boujemaa

    2016-06-14

    This paper considers the Bayesian filtering problem in high-dimensional nonlinear state-space systems. In such systems, classical particle filters (PFs) are impractical due to the prohibitive number of required particles to obtain reasonable performances. One approach that has been introduced to overcome this problem is the concept of multiple PFs (MPFs), where the state-space is split into low-dimensional subspaces and then a separate PF is applied to each subspace. Remarkable performances of MPF-like filters motivated our investigation here into a new strategy that combines the variational Bayesian approach to split the state-space with random sampling techniques, to derive a new computationally efficient MPF. The propagation of each particle in the prediction step of the resulting filter requires generating only a single particle in contrast with standard MPFs, for which a set of (children) particles is required. We present simulation results to evaluate the behavior of the proposed filter and compare its performances against standard PF and a MPF.

  19. A variational Bayesian multiple particle filtering scheme for large-dimensional systems

    KAUST Repository

    Ait-El-Fquih, Boujemaa; Hoteit, Ibrahim

    2016-01-01

    This paper considers the Bayesian filtering problem in high-dimensional nonlinear state-space systems. In such systems, classical particle filters (PFs) are impractical due to the prohibitive number of required particles to obtain reasonable performances. One approach that has been introduced to overcome this problem is the concept of multiple PFs (MPFs), where the state-space is split into low-dimensional subspaces and then a separate PF is applied to each subspace. Remarkable performances of MPF-like filters motivated our investigation here into a new strategy that combines the variational Bayesian approach to split the state-space with random sampling techniques, to derive a new computationally efficient MPF. The propagation of each particle in the prediction step of the resulting filter requires generating only a single particle in contrast with standard MPFs, for which a set of (children) particles is required. We present simulation results to evaluate the behavior of the proposed filter and compare its performances against standard PF and a MPF.

  20. Analysis using large-scale ringing data

    Directory of Open Access Journals (Sweden)

    Baillie, S. R.

    2004-06-01

    , synchrony is in fact a much more widespread process, with bird populations across wide areas showing similar trends and fluctuations as a result of common climatic and environmental factors (Paradis et al., 2000. Dispersal may also play an important role in such synchrony but its role is less well understood. Nigel Yoccoz and Rolf Ims (Yoccoz & Ims, 2004 show how synchrony can be investigated using data at three spatial scales taken from their field studies of the population dynamics of small mammals in North Norway. Small mammal abundance was estimated from trapping data using closed population models and also from total numbers of individuals captured. They use simulated data to show that synchrony, measured by the correlation coefficients between time series, was biased low by up to 30% when sampling variation was ignored. Appropriate analysis of such data will require simultaneous modelling of process and sampling variation, for example through the use of state–space models (Buckland et al., 2004. This view links back nicely to the approaches proposed by Andy Royle (Royle, 2004. Cycles in the abundance of small mammals have major affects on the demography of their predators, as is shown in the paper by Pertti Saurola and Charles Francis (Saurola & Francis, 2004. They report on the design and results of large–scale, long–term studies of owl populations by a network of amateur bird ringers in Finland. They show that breeding success varies with the stage of the microtine cycle. They also show how their data can be used to estimate dispersal over large spatial scales and illustrate the importance of correcting for uneven spatial variation in sampling effort. Further results from this study are reported in a companion paper within the population dynamics session (Francis & Saurola, 2004. Multi–species analyses of population dynamics are developed further in the paper by Romain Julliard (Julliard, 2004. He combines counts from the French Breeding Bird Survey with

  1. Optimization of Large-Scale Structural Systems

    DEFF Research Database (Denmark)

    Jensen, F. M.

    solutions to small problems with one or two variables to the optimization of large structures such as bridges, ships and offshore structures. The methods used for salving these problems have evolved from being classical differential calculus and calculus of variation to very advanced numerical techniques...

  2. Genomic variation among populations of threatened coral: Acropora cervicornis.

    Science.gov (United States)

    Drury, C; Dale, K E; Panlilio, J M; Miller, S V; Lirman, D; Larson, E A; Bartels, E; Crawford, D L; Oleksiak, M F

    2016-04-13

    Acropora cervicornis, a threatened, keystone reef-building coral has undergone severe declines (>90 %) throughout the Caribbean. These declines could reduce genetic variation and thus hamper the species' ability to adapt. Active restoration strategies are a common conservation approach to mitigate species' declines and require genetic data on surviving populations to efficiently respond to declines while maintaining the genetic diversity needed to adapt to changing conditions. To evaluate active restoration strategies for the staghorn coral, the genetic diversity of A. cervicornis within and among populations was assessed in 77 individuals collected from 68 locations along the Florida Reef Tract (FRT) and in the Dominican Republic. Genotyping by Sequencing (GBS) identified 4,764 single nucleotide polymorphisms (SNPs). Pairwise nucleotide differences (π) within a population are large (~37 %) and similar to π across all individuals. This high level of genetic diversity along the FRT is similar to the diversity within a small, isolated reef. Much of the genetic diversity (>90 %) exists within a population, yet GBS analysis shows significant variation along the FRT, including 300 SNPs with significant FST values and significant divergence relative to distance. There are also significant differences in SNP allele frequencies over small spatial scales, exemplified by the large FST values among corals collected within Miami-Dade county. Large standing diversity was found within each population even after recent declines in abundance, including significant, potentially adaptive divergence over short distances. The data here inform conservation and management actions by uncovering population structure and high levels of diversity maintained within coral collections among sites previously shown to have little genetic divergence. More broadly, this approach demonstrates the power of GBS to resolve differences among individuals and identify subtle genetic structure

  3. Genetic variation in bovine milk fat composition

    NARCIS (Netherlands)

    Stoop, W.M.

    2009-01-01

    In her thesis, Stoop shows that there is considerable genetic variation in milk fat composition, which opens opportunities to improve milk fat composition by selective breeding. Short and medium chain fatty acids had high heritabilities, whereas variation due to herd (mainly feed effects) was

  4. Variation of flow separation over large bedforms during a tidal cycle

    DEFF Research Database (Denmark)

    Lefebvre, A.; Ferret, Y.; Paarlberg, A.J.

    2013-01-01

    This study characterizes the shape of the flow separation zone over natural compound bedforms during a tidal cycle and investigates how the flow separation zone depends on changing flow conditions, water levels and bathymetry. Field data collected during a full tidal cycle over large ebb-oriented......This study characterizes the shape of the flow separation zone over natural compound bedforms during a tidal cycle and investigates how the flow separation zone depends on changing flow conditions, water levels and bathymetry. Field data collected during a full tidal cycle over large ebb......, no flow separation developed over the gentle slope of the flood lee side (3 to 5° on average). However, a small flow separation zone is often recognized near the crest, where the slope is locally up to 15°. The shape of the FSZ is not influenced by changes in current velocities or water levels...

  5. Regional geographic variations in kidney cancer incidence rates in European countries.

    Science.gov (United States)

    Li, Peng; Znaor, Ariana; Holcatova, Ivana; Fabianova, Eleonora; Mates, Dana; Wozniak, Magdalena B; Ferlay, Jacques; Scelo, Ghislaine

    2015-06-01

    Marked unexplained national variations in incidence rates of kidney cancer have been observed for decades in Europe. To investigate geographic variations at the regional level and identify European regions with high incidence rates of kidney cancer. Regional- and national-level incidence data were extracted from the Cancer Incidence in Five Continents databases, local cancer registry databases, and local published reports. World population age-standardised rates (ASRs) were calculated for the periods 2003-2007 and 1988-1992. Rates by period and sex were compared using map visualisation. During 2003-2007, the highest ASR was found in the Plzen region, Czech Republic (31.4/100,000 person-years in men). Other regions of the Czech Republic had ASRs of 18.6-27.5/100,000 in men, with a tendency for higher rates in regions south of Prague. Surrounding regions, including eastern Germany and regions of Slovakia and Austria, had medium-to-high incidence rates (13.0-16.8/100,000 in men). Three other areas in Europe showed higher incidence rates in men compared with the rest of the continent: Lithuania, Estonia, Latvia, and Belarus (15.0-17.6/100,000); Iceland (13.5/100,000), and northern Italy (up to 16.0/100,000). Similar regional differences were observed among women, with rates approximately half of those observed in men in the same region. In general, these regional geographic variations remained stable over the periods 1988-1992 and 2003-2007, although higher incidence rates were detected in the Baltic countries in 2003-2007. Several European regions show particularly high rates of kidney cancer incidence. Large variations were observed within countries covered by national health-care systems, implying that overdetection is not the major factor. We present regional geographic variations in kidney cancer incidence rates in Europe. We highlight several regions with high incidence rates where further studies should be conducted for cancer control and prevention. Copyright

  6. Simultaneous Structural Variation Discovery in Multiple Paired-End Sequenced Genomes

    Science.gov (United States)

    Hormozdiari, Fereydoun; Hajirasouliha, Iman; McPherson, Andrew; Eichler, Evan E.; Sahinalp, S. Cenk

    Next generation sequencing technologies have been decreasing the costs and increasing the world-wide capacity for sequence production at an unprecedented rate, making the initiation of large scale projects aiming to sequence almost 2000 genomes [1]. Structural variation detection promises to be one of the key diagnostic tools for cancer and other diseases with genomic origin. In this paper, we study the problem of detecting structural variation events in two or more sequenced genomes through high throughput sequencing . We propose to move from the current model of (1) detecting genomic variations in single next generation sequenced (NGS) donor genomes independently, and (2) checking whether two or more donor genomes indeed agree or disagree on the variations (in this paper we name this framework Independent Structural Variation Discovery and Merging - ISV&M), to a new model in which we detect structural variation events among multiple genomes simultaneously.

  7. SPATIALLY RESOLVED SPECTROSCOPY OF EUROPA’S LARGE-SCALE COMPOSITIONAL UNITS AT 3–4 μ m WITH KECK NIRSPEC

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, P. D.; Brown, M. E.; Trumbo, S. K. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Hand, K. P., E-mail: pfischer@caltech.edu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2017-01-01

    We present spatially resolved spectroscopic observations of Europa’s surface at 3–4 μ m obtained with the near-infrared spectrograph and adaptive optics system on the Keck II telescope. These are the highest quality spatially resolved reflectance spectra of Europa’s surface at 3–4 μ m. The observations spatially resolve Europa’s large-scale compositional units at a resolution of several hundred kilometers. The spectra show distinct features and geographic variations associated with known compositional units; in particular, large-scale leading hemisphere chaos shows a characteristic longward shift in peak reflectance near 3.7 μ m compared to icy regions. These observations complement previous spectra of large-scale chaos, and can aid efforts to identify the endogenous non-ice species.

  8. Seasonal variations of volcanic eruption frequencies

    Science.gov (United States)

    Stothers, Richard B.

    1989-01-01

    Do volcanic eruptions have a tendency to occur more frequently in the months of May and June? Some past evidence suggests that they do. The present study, based on the new eruption catalog of Simkin et al.(1981), investigates the monthly statistics of the largest eruptions, grouped according to explosive magnitude, geographical latitude, and year. At the 2-delta level, no month-to-month variations in eruption frequency are found to be statistically significant. Examination of previously published month-to-month variations suggests that they, too, are not statistically significant. It is concluded that volcanism, at least averaged over large portions of the globe, is probably not periodic on a seasonal or annual time scale.

  9. High-density SNP genotyping of tomato (Solanum lycopersicum L. reveals patterns of genetic variation due to breeding.

    Directory of Open Access Journals (Sweden)

    Sung-Chur Sim

    Full Text Available The effects of selection on genome variation were investigated and visualized in tomato using a high-density single nucleotide polymorphism (SNP array. 7,720 SNPs were genotyped on a collection of 426 tomato accessions (410 inbreds and 16 hybrids and over 97% of the markers were polymorphic in the entire collection. Principal component analysis (PCA and pairwise estimates of F(st supported that the inbred accessions represented seven sub-populations including processing, large-fruited fresh market, large-fruited vintage, cultivated cherry, landrace, wild cherry, and S. pimpinellifolium. Further divisions were found within both the contemporary processing and fresh market sub-populations. These sub-populations showed higher levels of genetic diversity relative to the vintage sub-population. The array provided a large number of polymorphic SNP markers across each sub-population, ranging from 3,159 in the vintage accessions to 6,234 in the cultivated cherry accessions. Visualization of minor allele frequency revealed regions of the genome that distinguished three representative sub-populations of cultivated tomato (processing, fresh market, and vintage, particularly on chromosomes 2, 4, 5, 6, and 11. The PCA loadings and F(st outlier analysis between these three sub-populations identified a large number of candidate loci under positive selection on chromosomes 4, 5, and 11. The extent of linkage disequilibrium (LD was examined within each chromosome for these sub-populations. LD decay varied between chromosomes and sub-populations, with large differences reflective of breeding history. For example, on chromosome 11, decay occurred over 0.8 cM for processing accessions and over 19.7 cM for fresh market accessions. The observed SNP variation and LD decay suggest that different patterns of genetic variation in cultivated tomato are due to introgression from wild species and selection for market specialization.

  10. Complete chloroplast genomes from apomictic Taraxacum (Asteraceae): Identity and variation between three microspecies

    Science.gov (United States)

    Majeský, Ľuboš; Schwarzacher, Trude; Gornall, Richard; Heslop-Harrison, Pat

    2017-01-01

    Chloroplast DNA sequences show substantial variation between higher plant species, and less variation within species, so are typically excellent markers to investigate evolutionary, population and genetic relationships and phylogenies. We sequenced the plastomes of Taraxacum obtusifrons Markl. (O978); T. stridulum Trávniček ined. (S3); and T. amplum Markl. (A978), three apomictic triploid (2n = 3x = 24) dandelions from the T. officinale agg. We aimed to characterize the variation in plastomes, define relationships and correlations with the apomictic microspecies status, and refine placement of the microspecies in the evolutionary or phylogenetic context of the Asteraceae. The chloroplast genomes of accessions O978 and S3 were identical and 151,322 bp long (where the nuclear genes are known to show variation), while A978 was 151,349 bp long. All three genomes contained 135 unique genes, with an additional copy of the trnF-GGA gene in the LSC region and 20 duplicated genes in the IR region, along with short repeats, the typical major Inverted Repeats (IR1 and IR2, 24,431bp long), and Large and Small Single Copy regions (LSC 83,889bp and SSC 18,571bp in O978). Between the two Taraxacum plastomes types, we identified 28 SNPs. The distribution of polymorphisms suggests some parts of the Taraxacum plastome are evolving at a slower rate. There was a hemi-nested inversion in the LSC region that is common to Asteraceae, and an SSC inversion from ndhF to rps15 found only in some Asteraceae lineages. A comparative repeat analysis showed variation between Taraxacum and the phylogenetically close genus Lactuca, with many more direct repeats of 40bp or more in Lactuca (1% larger plastome than Taraxacum). When individual genes and non-coding regions were for Asteraceae phylogeny reconstruction, not all showed the same evolutionary scenario suggesting care is needed for interpretation of relationships if a limited number of markers are used. Studying genotypic diversity in

  11. Hedgehog signaling mediates adaptive variation in a dynamic functional system in the cichlid feeding apparatus.

    Science.gov (United States)

    Hu, Yinan; Albertson, R Craig

    2014-06-10

    Adaptive variation in the craniofacial skeleton is a key component of resource specialization and habitat divergence in vertebrates, but the proximate genetic mechanisms that underlie complex patterns of craniofacial variation are largely unknown. Here we demonstrate that the Hedgehog (Hh) signaling pathway mediates widespread variation across a complex functional system that affects the kinematics of lower jaw depression--the opercular four-bar linkage apparatus--among Lake Malawi cichlids. By using a combined quantitative trait locus mapping and population genetics approach, we show that allelic variation in the Hh receptor, ptch1, affects the development of distinct bony elements in the head that represent two of three movable links in this functional system. The evolutionarily derived allele is found in species that feed from the water column, and is associated with shifts in anatomy that translate to a four-bar system capable of faster jaw rotation. Alternatively, the ancestral allele is found in species that feed on attached algae, and is associated with the development of a four-bar system that predicts slower jaw movement. Experimental manipulation of the Hh pathway during cichlid development recapitulates functionally salient natural variation in craniofacial geometry. In all, these results significantly extend our understanding of the mechanisms that fine-tune the craniofacial skeletal complex during adaptation to new foraging niches.

  12. Variations in the small-scale galactic magnetic field and short time-scale intensity variations of extragalactic radio sources

    International Nuclear Information System (INIS)

    Simonetti, J.H.

    1985-01-01

    Structure functions of the Faraday rotation measures (RMs) of extragalactic radio sources are used to investigate variations in the interstellar magnetic field on length scales of approx.0.01 to 100 pc. Model structure functions derived assuming a power-law power spectrum of irregularities in n/sub e/B, are compared with those observed. The results indicate an outer angular scale for RM variations of approximately less than or equal to 5 0 and evidence for RM variations on scales as small as 1'. Differences in the variance of n/sub e/B fluctuations for various lines of sight through the Galaxy are found. Comparison of pulsar scintillations in right- and left-circular polarizations yield an upper limit to the variations in n/sub e/ on a length scale of approx.10 11 cm. RMs were determined through high-velocity molecular flows in galactic star-formation regions, with the goal of constraining magnetic fields in and near the flows. RMs of 7 extragalactic sources with a approx.20 arcmin wide area seen through Cep A, fall in two groups separated by approx.150 rad m -2 - large given our knowledge of RM variations on small angular scales and possibly a result of the anisotropy of the high-velocity material

  13. Network hubs buffer environmental variation in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Sasha F Levy

    2008-11-01

    Full Text Available Regulatory and developmental systems produce phenotypes that are robust to environmental and genetic variation. A gene product that normally contributes to this robustness is termed a phenotypic capacitor. When a phenotypic capacitor fails, for example when challenged by a harsh environment or mutation, the system becomes less robust and thus produces greater phenotypic variation. A functional phenotypic capacitor provides a mechanism by which hidden polymorphism can accumulate, whereas its failure provides a mechanism by which evolutionary change might be promoted. The primary example to date of a phenotypic capacitor is Hsp90, a molecular chaperone that targets a large set of signal transduction proteins. In both Drosophila and Arabidopsis, compromised Hsp90 function results in pleiotropic phenotypic effects dependent on the underlying genotype. For some traits, Hsp90 also appears to buffer stochastic variation, yet the relationship between environmental and genetic buffering remains an important unresolved question. We previously used simulations of knockout mutations in transcriptional networks to predict that many gene products would act as phenotypic capacitors. To test this prediction, we use high-throughput morphological phenotyping of individual yeast cells from single-gene deletion strains to identify gene products that buffer environmental variation in Saccharomyces cerevisiae. We find more than 300 gene products that, when absent, increase morphological variation. Overrepresented among these capacitors are gene products that control chromosome organization and DNA integrity, RNA elongation, protein modification, cell cycle, and response to stimuli such as stress. Capacitors have a high number of synthetic-lethal interactions but knockouts of these genes do not tend to cause severe decreases in growth rate. Each capacitor can be classified based on whether or not it is encoded by a gene with a paralog in the genome. Capacitors with a

  14. Annual and semiannual variations in the ionospheric F2-layer: II. Physical discussion

    Directory of Open Access Journals (Sweden)

    H. Rishbeth

    Full Text Available The companion paper by Zou et al. shows that the annual and semiannual variations in the peak F2-layer electron density (NmF2 at midlatitudes can be reproduced by a coupled thermosphere-ionosphere computational model (CTIP, without recourse to external influences such as the solar wind, or waves and tides originating in the lower atmosphere. The present work discusses the physics in greater detail. It shows that noon NmF2 is closely related to the ambient atomic/molecular concentration ratio, and suggests that the variations of NmF2 with geographic and magnetic longitude are largely due to the geometry of the auroral ovals. It also concludes that electric fields play no important part in the dynamics of the midlatitude thermosphere. Our modelling leads to the following picture of the global three-dimensional thermospheric circulation which, as envisaged by Duncan, is the key to explaining the F2-layer variations. At solstice, the almost continuous solar input at high summer latitudes drives a prevailing summer-to-winter wind, with upwelling at low latitudes and throughout most of the summer hemisphere, and a zone of downwelling in the winter hemisphere, just equatorward of the auroral oval. These motions affect thermospheric composition more than do the alternating day/night (up-and-down motions at equinox. As a result, the thermosphere as a whole is more molecular at solstice than at equinox. Taken in conjunction with the well-known relation of F2-layer electron density to the atomic/molecular ratio in the neutral air, this explains the F2-layer semiannual effect in NmF2 that prevails at low and middle latitudes. At higher midlatitudes, the seasonal behaviour depends on the geographic latitude of the winter downwelling zone, though the effect of the composition changes is modified by the large solar zenith angle at midwinter. The zenith angle effect is especially important in longitudes far from the magnetic

  15. The circadian variation of premature atrial contractions

    DEFF Research Database (Denmark)

    Larsen, Bjørn Strøier; Kumarathurai, Preman; Nielsen, Olav W

    2016-01-01

    AIMS: The aim of the study was to assess a possible circadian variation of premature atrial contractions (PACs) in a community-based population and to determine if the daily variation could be used to assess a more vulnerable period of PACs in predicting later incidence of atrial fibrillation (AF...... variation in heart rate. After adjusting for relevant risk factors, the risk of AF was equal in all time intervals throughout the day. CONCLUSION: Premature atrial contractions showed a circadian variation in subjects with frequent PACs. No specific time interval of the day was more predictive of AF than...

  16. High biological variation of serum hyaluronic acid and Hepascore, a biochemical marker model for the prediction of liver fibrosis.

    Science.gov (United States)

    Rossi, Enrico; Adams, Leon A; Ching, Helena L; Bulsara, Max; MacQuillan, Gerry C; Jeffrey, Gary P

    2013-05-01

    Serum hyaluronic acid and biochemical models which require hyaluronic acid analysis are commonly used as predictors of liver fibrosis in patients with chronic liver disease, however biological variation data for hyaluronic acid are deficient. Four serial serum samples were obtained at weekly intervals from healthy volunteers and patients with chronic hepatitis B, chronic hepatitis C and non- alcoholic fatty liver disease (NAFLD; 20 in each group). The within-individual week-to-week variation (CVI) and reference change values for hyaluronic acid, α₂-macroglobulin and Hepascore were obtained. Hepascore is calculated from hyaluronic acid, α2-macroglobulin, bilirubin and γ-glutamyltransferase activity. Hyaluronic acid displayed large within-individual variation, the CVI values were 62% in healthy subjects, 38% in hepatitis C, 37% in hepatitis B and 36% in NAFLD patients. Hepascore CVIs were 43% in healthy subjects, 24% in hepatitis C, 28% in hepatitis B and 39% in NAFLD patients. α₂-Macroglobulin was much less variable with CVIs ranging from 4.4% to 7.6%. Bland-Altman plots of week-to-week variations showed rates of significant disagreement for samples collected in any 2 successive weeks varied from 5% in NAFLD patients to 8.3% in healthy subjects. When using non-fasting serum samples, hyaluronic acid and to a lesser extent, the Hepascore model display large within-individual variations in both health and chronic liver disease. This information is critical for interpreting the significance of both single measurements and changes in serial measurements.

  17. Spectral analysis of pipe-to-soil potentials with variations of the Earth's magnetic field in the Australian region

    Science.gov (United States)

    Marshall, R. A.; Waters, C. L.; Sciffer, M. D.

    2010-05-01

    Long, steel pipelines used to transport essential resources such as gas and oil are potentially vulnerable to space weather. In order to inhibit corrosion, the pipelines are usually coated in an insulating material and maintained at a negative electric potential with respect to Earth using cathodic protection units. During periods of enhanced geomagnetic activity, potential differences between the pipeline and surrounding soil (referred to as pipe-to-soil potentials (PSPs)) may exhibit large voltage swings which place the pipeline outside the recommended "safe range" and at an increased risk of corrosion. The PSP variations result from the "geoelectric" field at the Earth's surface and associated geomagnetic field variations. Previous research investigating the relationship between the surface geoelectric field and geomagnetic source fields has focused on the high-latitude regions where line currents in the ionosphere E region are often the assumed source of the geomagnetic field variations. For the Australian region Sq currents also contribute to the geomagnetic field variations and provide the major contribution during geomagnetic quiet times. This paper presents the results of a spectral analysis of PSP measurements from four pipeline networks from the Australian region with geomagnetic field variations from nearby magnetometers. The pipeline networks extend from Queensland in the north of Australia to Tasmania in the south and provide PSP variations during both active and quiet geomagnetic conditions. The spectral analyses show both consistent phase and amplitude relationships across all pipelines, even for large separations between magnetometer and PSP sites and for small-amplitude signals. Comparison between the observational relationships and model predictions suggests a method for deriving a geoelectric field proxy suitable for indicating PSP-related space weather conditions.

  18. Detection of Coxiella burnetii in Ambient Air after a Large Q Fever Outbreak.

    Directory of Open Access Journals (Sweden)

    Myrna M T de Rooij

    Full Text Available One of the largest Q fever outbreaks ever occurred in the Netherlands from 2007-2010, with 25 fatalities among 4,026 notified cases. Airborne dispersion of Coxiella burnetii was suspected but not studied extensively at the time. We investigated temporal and spatial variation of Coxiella burnetii in ambient air at residential locations in the most affected area in the Netherlands (the South-East, in the year immediately following the outbreak. One-week average ambient particulate matter < 10 μm samples were collected at eight locations from March till September 2011. Presence of Coxiella burnetii DNA was determined by quantitative polymerase chain reaction. Associations with various spatial and temporal characteristics were analyzed by mixed logistic regression. Coxiella burnetii DNA was detected in 56 out of 202 samples (28%. Airborne Coxiella burnetii presence showed a clear seasonal pattern coinciding with goat kidding. The spatial variation was significantly associated with number of goats on the nearest goat farm weighted by the distance to the farm (OR per IQR: 1.89, CI: 1.31-2.76. We conclude that in the year after a large Q fever outbreak, temporal variation of airborne Coxiella burnetii is suggestive to be associated with goat kidding, and spatial variation with distance to and size of goat farms. Aerosol measurements show to have potential for source identification and attribution of an airborne pathogen, which may also be applicable in early stages of an outbreak.

  19. Geographic variation in expenditures for Workers' Compensation hospitalized claims.

    Science.gov (United States)

    Miller, T R; Levy, D T

    1999-02-01

    Past literature finds considerable variation in the cost of physician care and in the utilization of medical procedures. Variation in the cost of hospitalized care has received little attention. We examine injury costs of hospitalized claims across states. Multivariate regression analysis is used to isolate state variations, while controlling for personal and injury characteristics, and state characteristics. Injuries to workers filing Workers' Compensation lost workday claims. About 35,000 randomly sampled Workers' Compensation claims from 17 states filed between 1979 and 1988. Medical payments per episode of three injury groups: upper and lower extremity fractures and dislocations, other upper extremity injuries, and back strains and sprains. Statistical analyses reveal considerable variation in expenditures for hospitalized injuries across states, even after controlling for case mix and state characteristics. A substantial portion of the variation is explained by state rate regulations; regulated states have lower costs. The large variation in costs suggests a potential to affect the costs of hospitalized care. Efforts should be directed at those areas that have higher costs without sufficient input price, quality, or case mix justification.

  20. Variational field theoretic approach to relativistiv meson-nucleon scattering

    International Nuclear Information System (INIS)

    Alexandrou, C.; Rosenfelder, R.; Schreiber, A.W.; TRIUMF, Vancouver, BC; Adelaide Univ., SA; Adelaide Univ., SA; Univ. Adelaide

    1998-01-01

    Non-perturbative polaron variational methods are applied, within the so-called particle or worldline representation of relativistic field theory, to study scattering in the context of the scalar Wick-Cutkosky model. Important features of the variational calculation are that it is a controlled approximation scheme valid for arbitrary coupling strengths, the Green functions have all the cuts and poles expected for the exact result at any order in perturbation theory and that the variational parameters are simultaneously sensitive to the infrared as well as the ultraviolet behaviour of the theory. We generalize the previously used quadratic trial action by allowing more freedom for off-shell propagation without a change in the on-shell variational equations and evaluate the scattering amplitude at first order in the variational scheme. Particular attention is paid to the s-channel scattering near threshold because here non-perturbative effects can be large. We check the unitarity of a our numerical calculation and find it greatly improved compared to perturbation theory and to the zeroth order variational results. (orig.)

  1. Precipitation Pattern Controls on the Dynamics and Subsequent Export of Large Wood from River Catchments

    Science.gov (United States)

    Seo, J.; Nakamura, F.; Chun, K.; Grant, G. E.

    2011-12-01

    In-stream large wood (LW) has a critical impact on the geomorphic and ecological character in river catchments, yet relatively little is known about variations in its dynamics and subsequent export in relation to different precipitation patterns and intensities. To understand these variations we used the annual volume of LW removed from 42 reservoirs in Japan and daily precipitation at or near the reservoir sites. Daily precipitation data were transformed into effective precipitation to evaluate trends in both current and antecedent precipitation, and these data were then used to explain basin variation in LW export. Model selection with generalized linear mixed models revealed that the precipitation pattern and intensity controlling LW export in small, intermediate, and large watersheds differed with latitude along the Japanese archipelago. LW export in small watersheds was well explained by effective precipitation greater than 120 mm, and showed little latitudinal variation. In contrast, LW export in intermediate and large watersheds was well explained by daily precipitation greater than 40 mm and 60 mm, respectively, and varied with latitude. In small watersheds with narrow channels and low stream discharges, mass movements (such as landslides and debris flows) are major factors in the production and transport of LW. Thus LW export in small watersheds appears to be regulated by the effective precipitation required to initiate mass movements, and shows little latitudinal change. In intermediate and large watersheds with wide channels and high stream discharges, heavy rainfall and subsequent floods regulate buoyant depth influencing the initiation of LW mobility, and thus control the amount of LW exported. In southern and central Japan, intense rainfall accompanying typhoons or localized torrential downpours lead to geomorphic disturbances, which produce massive amounts of LW delivery into channels. However, these pieces are constantly removed by high streamflows

  2. Determinants, reproducibility, and seasonal variation of ergosterol levels in house dust.

    Science.gov (United States)

    Leppänen, H K; Nevalainen, A; Vepsäläinen, A; Roponen, M; Täubel, M; Laine, O; Rantakokko, P; von Mutius, E; Pekkanen, J; Hyvärinen, A

    2014-06-01

    This study aimed to clarify the determinants that affect the concentrations of ergosterol and viable fungi in house dust and to examine the seasonal variation and reproducibility of ergosterol concentrations indoors. In studying the determinants, dust samples from living room floors and vacuum cleaner dust bags were collected from 107 farming and 105 non-farming homes. Ergosterol levels were determined with gas chromatography-mass spectrometry,and the dust bag dust was cultivated for enumeration of fungal genera. Lifestyle and environmental factors, for example using of the fireplace, and visible mold observations in homes, explained 20–26% of the variation of fungal concentrations. For the reproducibility study, samples were collected from five urban homes in four different seasons. The reproducibility of ergosterol determinations within a sample was excellent (ICC = 89.8) for floor dust and moderate (ICC = 63.8) for dust bag dust, but poor when sampling the same home throughout a year (ICC = 31.3 and 12.6, respectively) due to large temporal variation in ergosterol concentrations. In conclusion, environmental characteristics only partially predicted the variation of fungal concentrations. Based on these studies, we recommend repeated sampling of dust over time if one seeks to adequately describe overall fungal levels and exposure in a home. This study shows that levels of ergosterol and viable fungi in house dust are related to visible mold observations. Only 20% of the variation in fungal levels can be explained with questionnaires, and therefore, environmental samples need to be taken in addition. Reproducibility of ergosterol determination was excellent for floor dust, and thus, ergosterol measurements from floor dust samples could be suitable for assessing the fungal load in building investigations. The temporal variation needs to be taken into account when describing the ergosterol concentration of urban homes.

  3. Segmentation by Large Scale Hypothesis Testing - Segmentation as Outlier Detection

    DEFF Research Database (Denmark)

    Darkner, Sune; Dahl, Anders Lindbjerg; Larsen, Rasmus

    2010-01-01

    a microscope and we show how the method can handle transparent particles with significant glare point. The method generalizes to other problems. THis is illustrated by applying the method to camera calibration images and MRI of the midsagittal plane for gray and white matter separation and segmentation......We propose a novel and efficient way of performing local image segmentation. For many applications a threshold of pixel intensities is sufficient but determine the appropriate threshold value can be difficult. In cases with large global intensity variation the threshold value has to be adapted...... locally. We propose a method based on large scale hypothesis testing with a consistent method for selecting an appropriate threshold for the given data. By estimating the background distribution we characterize the segment of interest as a set of outliers with a certain probability based on the estimated...

  4. Climatic variation and age-specific survival in Asian elephants from Myanmar.

    Science.gov (United States)

    Mumby, Hannah S; Courtiol, Alexandre; Mar, Khyne U; Lummaa, Virpi

    2013-05-01

    Concern about climate change has intensified interest in understanding how climatic variability affects animal life histories. Despite such effects being potentially most dramatic in large, long-lived, and slowly reproducing terrestrial mammals, little is known of the effects of climatic variation on survival in those species. Asian elephants (Elephas maximus) are endangered across their distribution, and inhabit regions characterized by high seasonality of temperature and rainfall. We investigated the effects of monthly climatic variation on survival and causes of death in Asian elephants using a unique demographic data set of 1024 semi-captive, longitudinally monitored elephants from four sites in Myanmar between 1965 and 2000. Temperature had a significant effect on survival in both sexes and across all ages. For elephants between 1 month and 17 years of age, maximal survival was reached at -24 degrees C, and any departures from this temperature increased mortality, whereas neonates and mature elephants had maximal survival at even lower temperatures. Although males experienced higher mortality overall, sex differences in these optimal temperatures were small. Because the elephants spent more time during a year in temperatures above 24 degrees C than in temperatures below it, most deaths occurred at hot (temperatures>24 degrees C) rather than cold periods. Decreased survival at higher temperatures resulted partially from increased deaths from infectious disease and heat stroke, whereas the lower survival in the coldest months was associated with an increase in noninfectious diseases and poor health in general. Survival was also related to rainfall, with the highest survival rates during the wettest months for all ages and sexes. Our results show that even the normal-range monsoon variation in climate can exert a large impact on elephant survival in Myanmar, leading to extensive absolute differences in mortality; switching from favorable to unfavorable climatic

  5. Solar UV Variations During the Decline of Cycle 23

    Science.gov (United States)

    DeLand, Matthew, T.; Cebula, Richard P.

    2011-01-01

    Characterization of temporal and spectral variations in solar ultraviolet irradiance over a solar cycle is essential for understanding the forcing of Earth's atmosphere and climate. Satellite measurements of solar UV variability for solar cycles 21, 22, and 23 show consistent solar cycle irradiance changes at key wavelengths (e.g. 205 nm, 250 nm) within instrumental uncertainties. All historical data sets also show the same relative spectral dependence for both short-term (rotational) and long-term (solar cycle) variations. Empirical solar irradiance models also produce long-term solar UV variations that agree well with observational data. Recent UV irradiance data from the Solar Radiation and Climate Experiment (SORCE) Spectral Irradiance Monitor (SIM) and Solar Stellar Irradiance Comparison Experiment (SOLSTICE) instruments covering the declining phase of Cycle 23 present a different picture oflong-term solar variations from previous results. Time series of SIM and SOLSTICE spectral irradiance data between 2003 and 2007 show solar variations that greatly exceed both previous measurements and predicted irradiance changes over this period, and the spectral dependence of the SIM and SOLSTICE variations during these years do not show features expected from solar physics theory. The use of SORCE irradiance variations in atmospheric models yields substantially different middle atmosphere ozone responses in both magnitude and vertical structure. However, short-term solar variability derived from SIM and SOLSTICE UV irradiance data is consistent with concurrent solar UV measurements from other instruments, as well as previous results, suggesting no change in solar physics. Our analysis of short-term solar variability is much less sensitive to residual instrument response changes than the observations of long-term variations. The SORCE long-term UV results can be explained by under-correction of instrument response changes during the first few years of measurements

  6. 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...... of Arabidopsis thaliana, coupled with 39 years of field data on aphid abundance, to (i) demonstrate that geographic patterns in a polymorphic defense locus (GS-ELONG) are strongly correlated with changes in the relative abundance of two specialist aphids; and (ii) demonstrate differential selection by the two...... aphids on GS-ELONG, using a multigeneration selection experiment. We thereby show a causal link between variation in abundance of the two specialist aphids and the geographic pattern at GS-ELONG, which highlights the potency of natural enemies as selective forces....

  7. Spatiotemporal Variation and Networks in the Mycobiome of the Wheat Canopy

    Directory of Open Access Journals (Sweden)

    Rumakanta Sapkota

    2017-08-01

    Full Text Available The phyllosphere is an important habitat for a diverse microbiome and an important entry point for many pathogens. Factors that shape the phyllosphere microbiome and also the co-existence among members and how they affect disease development are largely understudied. In this study we examined the wheat mycobiome by using metabarcoding of the fungal ITS1 region. Leaf samples were taken from four cultivars grown at two locations in Denmark. Samples were taken from the three uppermost leaves and at three growth stages to better understand spatiotemporal variation of the mycobiome. Analysis of read abundances showed that geographical location had a major effect in shaping the mycobiome in the total dataset, but also leaf position, growth stage and cultivar were important drivers of fungal communities. Cultivar was most important in explaining variation in older leaves whereas location better explained the variation in younger leaves, suggesting that communities are shaped over time by the leaf environment. Network analysis revealed negative co-existence between Zymoseptoria tritici and the yeasts Sporobolomyces, Dioszegia, and Cystofilobasidiaceae. The relative abundance of Z. tritici and the yeasts was relatively constant between individual samples, suggesting that fast growing fungi rapidly occupy empty space in the phyllosphere.

  8. Matter tensor from the Hilbert variational principle

    International Nuclear Information System (INIS)

    Pandres, D. Jr.

    1976-01-01

    We consider the Hilbert variational principle which is conventionally used to derive Einstein's equations for the source-free gravitational field. We show that at least one version of the equivalence principle suggests an alternative way of performing the variation, resulting in a different set of Einstein equations with sources automatically present. This illustrates a technique which may be applied to any theory that is derived from a variational principle and that admits a gauge group. The essential point is that, if one first imposes a gauge condition and then performs the variation, one obtains field equations with source terms which do not appear if one first performs the variation and then imposes the gauge condition. A second illustration is provided by the variational principle conventionally used to derive Maxwell's equations for the source-free electromagnetic field. If one first imposes the Lorentz gauge condition and then performs the variation, one obtains Maxwell's equations with sources present

  9. Effects of a large wildfire on vegetation structure in a variable fire mosaic.

    Science.gov (United States)

    Foster, C N; Barton, P S; Robinson, N M; MacGregor, C I; Lindenmayer, D B

    2017-12-01

    Management guidelines for many fire-prone ecosystems highlight the importance of maintaining a variable mosaic of fire histories for biodiversity conservation. Managers are encouraged to aim for fire mosaics that are temporally and spatially dynamic, include all successional states of vegetation, and also include variation in the underlying "invisible mosaic" of past fire frequencies, severities, and fire return intervals. However, establishing and maintaining variable mosaics in contemporary landscapes is subject to many challenges, one of which is deciding how the fire mosaic should be managed following the occurrence of large, unplanned wildfires. A key consideration for this decision is the extent to which the effects of previous fire history on vegetation and habitats persist after major wildfires, but this topic has rarely been investigated empirically. In this study, we tested to what extent a large wildfire interacted with previous fire history to affect the structure of forest, woodland, and heath vegetation in Booderee National Park in southeastern Australia. In 2003, a summer wildfire burned 49.5% of the park, increasing the extent of recently burned vegetation (post-fire) to more than 72% of the park area. We tracked the recovery of vegetation structure for nine years following the wildfire and found that the strength and persistence of fire effects differed substantially between vegetation types. Vegetation structure was modified by wildfire in forest, woodland, and heath vegetation, but among-site variability in vegetation structure was reduced only by severe fire in woodland vegetation. There also were persistent legacy effects of the previous fire regime on some attributes of vegetation structure including forest ground and understorey cover, and woodland midstorey and overstorey cover. For example, woodland midstorey cover was greater on sites with higher fire frequency, irrespective of the severity of the 2003 wildfire. Our results show that even

  10. Dispersion Measure Variation of Repeating Fast Radio Burst Sources

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yuan-Pei; Zhang, Bing, E-mail: yypspore@gmail.com, E-mail: zhang@physics.unlv.edu [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2017-09-20

    The repeating fast radio burst (FRB) 121102 was recently localized in a dwarf galaxy at a cosmological distance. The dispersion measure (DM) derived for each burst from FRB 121102 so far has not shown significant evolution, even though an apparent increase was recently seen with newly detected VLA bursts. It is expected that more repeating FRB sources may be detected in the future. In this work, we investigate a list of possible astrophysical processes that might cause DM variation of a particular FRB source. The processes include (1) cosmological scale effects such as Hubble expansion and large-scale structure fluctuations; (2) FRB local effects such as gas density fluctuation, expansion of a supernova remnant (SNR), a pulsar wind nebula, and an H ii region; and (3) the propagation effect due to plasma lensing. We find that the DM variations contributed by the large-scale structure are extremely small, and any observable DM variation is likely caused by the plasma local to the FRB source. In addition to mechanisms that decrease DM over time, we suggest that an FRB source in an expanding SNR around a nearly neutral ambient medium during the deceleration (Sedov–Taylor and snowplow) phases or in a growing H ii region can increase DM. Some effects (e.g., an FRB source moving in an H ii region or plasma lensing) can produce either positive or negative DM variations. Future observations of DM variations of FRB 121102 and other repeating FRB sources can provide important clues regarding the physical origin of these sources.

  11. Dispersion Measure Variation of Repeating Fast Radio Burst Sources

    International Nuclear Information System (INIS)

    Yang, Yuan-Pei; Zhang, Bing

    2017-01-01

    The repeating fast radio burst (FRB) 121102 was recently localized in a dwarf galaxy at a cosmological distance. The dispersion measure (DM) derived for each burst from FRB 121102 so far has not shown significant evolution, even though an apparent increase was recently seen with newly detected VLA bursts. It is expected that more repeating FRB sources may be detected in the future. In this work, we investigate a list of possible astrophysical processes that might cause DM variation of a particular FRB source. The processes include (1) cosmological scale effects such as Hubble expansion and large-scale structure fluctuations; (2) FRB local effects such as gas density fluctuation, expansion of a supernova remnant (SNR), a pulsar wind nebula, and an H ii region; and (3) the propagation effect due to plasma lensing. We find that the DM variations contributed by the large-scale structure are extremely small, and any observable DM variation is likely caused by the plasma local to the FRB source. In addition to mechanisms that decrease DM over time, we suggest that an FRB source in an expanding SNR around a nearly neutral ambient medium during the deceleration (Sedov–Taylor and snowplow) phases or in a growing H ii region can increase DM. Some effects (e.g., an FRB source moving in an H ii region or plasma lensing) can produce either positive or negative DM variations. Future observations of DM variations of FRB 121102 and other repeating FRB sources can provide important clues regarding the physical origin of these sources.

  12. Large scale mass redistribution and surface displacement from GRACE and SLR

    Science.gov (United States)

    Cheng, M.; Ries, J. C.; Tapley, B. D.

    2012-12-01

    Mass transport between the atmosphere, ocean and solid earth results in the temporal variations in the Earth gravity field and loading induced deformation of the Earth. Recent space-borne observations, such as GRACE mission, are providing extremely high precision temporal variations of gravity field. The results from 10-yr GRACE data has shown a significant annual variations of large scale vertical and horizontal displacements occurring over the Amazon, Himalayan region and South Asia, African, and Russian with a few mm amplitude. Improving understanding from monitoring and modeling of the large scale mass redistribution and the Earth's response are a critical for all studies in the geosciences, in particular for determination of Terrestrial Reference System (TRS), including geocenter motion. This paper will report results for the observed seasonal variations in the 3-dimentional surface displacements of SLR and GPS tracking stations and compare with the prediction from time series of GRACE monthly gravity solution.

  13. Large-scale climatic anomalies affect marine predator foraging behaviour and demography

    Science.gov (United States)

    Bost, Charles A.; Cotté, Cedric; Terray, Pascal; Barbraud, Christophe; Bon, Cécile; Delord, Karine; Gimenez, Olivier; Handrich, Yves; Naito, Yasuhiko; Guinet, Christophe; Weimerskirch, Henri

    2015-10-01

    Determining the links between the behavioural and population responses of wild species to environmental variations is critical for understanding the impact of climate variability on ecosystems. Using long-term data sets, we show how large-scale climatic anomalies in the Southern Hemisphere affect the foraging behaviour and population dynamics of a key marine predator, the king penguin. When large-scale subtropical dipole events occur simultaneously in both subtropical Southern Indian and Atlantic Oceans, they generate tropical anomalies that shift the foraging zone southward. Consequently the distances that penguins foraged from the colony and their feeding depths increased and the population size decreased. This represents an example of a robust and fast impact of large-scale climatic anomalies affecting a marine predator through changes in its at-sea behaviour and demography, despite lack of information on prey availability. Our results highlight a possible behavioural mechanism through which climate variability may affect population processes.

  14. Solar cycle variations of geocoronal balmer α emission

    International Nuclear Information System (INIS)

    Nossal, S.; Reynolds, R.J.; Roesler, F.L.; Scherb, F.

    1993-01-01

    Observations of the geocoronal Balmer in nightglow have been made from Wisconsin for more than a solar cycle with an internally consistent intensity reference to standard astronomical nebulae. These measurements were made with a double etalon, pressure-scanned, 15-cm aperture Fabry-Perot interferometer. The resulting long time data provides an opportunity to examine solar cycle influence on the mid-latitude exosphere and to address accompanying questions concerning the degree to which the exosphere is locally static or changing. The exospheric Balmer α absolute intensity measurements reported here show no statistically significant variations throughout the solar cycle when the variation with viewing geometry is removed by normalizing the data to reference exospheric model predictions by Anderson et al. However, the relative intensity dependence on solar depression angle does show a solar cycle variation. This variation suggests a possible related variation in the exospheric hydrogen density profile, although other interpretations are also possible. The results suggest that additional well-calibrated data taken over a longer time span could probe low-amplitude variations over the solar cycle and test predictions of a slow monotonic increase in exospheric hydrogen arising from greenhouse gases. 21 refs., 9 figs., 2 tabs

  15. When tractography meets tracer injections: a systematic study of trends and variation sources of diffusion-based connectivity.

    Science.gov (United States)

    Aydogan, Dogu Baran; Jacobs, Russell; Dulawa, Stephanie; Thompson, Summer L; Francois, Maite Christi; Toga, Arthur W; Dong, Hongwei; Knowles, James A; Shi, Yonggang

    2018-04-16

    Tractography is a powerful technique capable of non-invasively reconstructing the structural connections in the brain using diffusion MRI images, but the validation of tractograms is challenging due to lack of ground truth. Owing to recent developments in mapping the mouse brain connectome, high-resolution tracer injection-based axonal projection maps have been created and quickly adopted for the validation of tractography. Previous studies using tracer injections mainly focused on investigating the match in projections and optimal tractography protocols. Being a complicated technique, however, tractography relies on multiple stages of operations and parameters. These factors introduce large variabilities in tractograms, hindering the optimization of protocols and making the interpretation of results difficult. Based on this observation, in contrast to previous studies, in this work we focused on quantifying and ranking the amount of performance variation introduced by these factors. For this purpose, we performed over a million tractography experiments and studied the variability across different subjects, injections, anatomical constraints and tractography parameters. By using N-way ANOVA analysis, we show that all tractography parameters are significant and importantly performance variations with respect to the differences in subjects are comparable to the variations due to tractography parameters, which strongly underlines the importance of fully documenting the tractography protocols in scientific experiments. We also quantitatively show that inclusion of anatomical constraints is the most significant factor for improving tractography performance. Although this critical factor helps reduce false positives, our analysis indicates that anatomy-informed tractography still fails to capture a large portion of axonal projections.

  16. Detection of Variation in Long-Term Micropropagated Mature Pistachio via DNA-Based Molecular Markers.

    Science.gov (United States)

    Akdemir, Hülya; Suzerer, Veysel; Tilkat, Engin; Onay, Ahmet; Çiftçi, Yelda Ozden

    2016-12-01

    Determination of genetic stability of in vitro-grown plantlets is needed for safe and large-scale production of mature trees. In this study, genetic variation of long-term micropropagated mature pistachio developed through direct shoot bud regeneration using apical buds (protocol A) and in vitro-derived leaves (protocol B) was assessed via DNA-based molecular markers. Randomly amplified polymorphic DNA (RAPD), inter-simple sequence repeat (ISSR), and amplified fragment length polymorphism (AFLP) were employed, and the obtained PIC values from RAPD (0.226), ISSR (0.220), and AFLP (0.241) showed that micropropagation of pistachio for different periods of time resulted in "reasonable polymorphism" among donor plant and its 18 clones. Mantel's test showed a consistence polymorphism level between marker systems based on similarity matrices. In conclusion, this is the first study on occurrence of genetic variability in long-term micropropagated mature pistachio plantlets. The obtained results clearly indicated that different marker approaches used in this study are reliable for assessing tissue culture-induced variations in long-term cultured pistachio plantlets.

  17. CoNVaQ: a web tool for copy number variation-based association studies

    DEFF Research Database (Denmark)

    Larsen, Simon Jonas; do Canto, Luisa Matos; Rogatto, Silvia Regina

    2018-01-01

    Copy number variations (CNVs) are large segments of the genome that are duplicated or deleted. Structural variations in the genome have been linked to many complex diseases. Similar to how genome-wide association studies (GWAS) have helped discover single-nucleotide polymorphisms linked to diseas...

  18. MetaRanker 2.0: a web server for prioritization of genetic variation data

    DEFF Research Database (Denmark)

    Pers, Tune Hannes; Dworzynski, Piotr; Thomas, Cecilia Engel

    2013-01-01

    MetaRanker 2.0 is a web server for prioritization of common and rare frequency genetic variation data. Based on heterogeneous data sets including genetic association data, protein–protein interactions, large-scale text-mining data, copy number variation data and gene expression experiments, Meta...

  19. Periodic weather and climate variations

    International Nuclear Information System (INIS)

    Ivanov, Vladimir V

    2002-01-01

    Variations in meteorological parameters are largely due to periodic processes and can be forecast for several years. Many such processes are related to astronomical factors such as the gravitational influences of the Moon and the Sun, and the modulation of solar irradiance by lunar and planetary motion. The Moon, Jupiter, and Venus have the strongest effect. These influences produce lines in the spectra of meteorological variations, which are combinations of the harmonics of the frequencies of revolution of the planets, the Earth, and the Moon around the Sun with the harmonics of the lunar revolution around the Earth. Due to frequency differences between the orbital and radial motions, fine spectral features of three types appear: line splitting, line-profile complications due to radial oscillations, and additional lines due to the combination of radial-oscillation frequencies with perturbation harmonics. (reviews of topical problems)

  20. Fish habitat selection in a large hydropeaking river: Strong individual and temporal variations revealed by telemetry.

    Science.gov (United States)

    Capra, Hervé; Plichard, Laura; Bergé, Julien; Pella, Hervé; Ovidio, Michaël; McNeil, Eric; Lamouroux, Nicolas

    2017-02-01

    Modeling individual fish habitat selection in highly variable environments such as hydropeaking rivers is required for guiding efficient management decisions. We analyzed fish microhabitat selection in the heterogeneous hydraulic and thermal conditions (modeled in two-dimensions) of a reach of the large hydropeaking Rhône River locally warmed by the cooling system of a nuclear power plant. We used modern fixed acoustic telemetry techniques to survey 18 fish individuals (five barbels, six catfishes, seven chubs) signaling their position every 3s over a three-month period. Fish habitat selection depended on combinations of current microhabitat hydraulics (e.g. velocity, depth), past microhabitat hydraulics (e.g. dewatering risk or maximum velocities during the past 15days) and to a lesser extent substrate and temperature. Mixed-effects habitat selection models indicated that individual effects were often stronger than specific effects. In the Rhône, fish individuals appear to memorize spatial and temporal environmental changes and to adopt a "least constraining" habitat selection. Avoiding fast-flowing midstream habitats, fish generally live along the banks in areas where the dewatering risk is high. When discharge decreases, however, they select higher velocities but avoid both dewatering areas and very fast-flowing midstream habitats. Although consistent with the available knowledge on static fish habitat selection, our quantitative results demonstrate temporal variations in habitat selection, depending on individual behavior and environmental history. Their generality could be further tested using comparative experiments in different environmental configurations. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Variation in age and size in Fennoscandian three-spined sticklebacks (Gasterosteus aculeatus).

    Science.gov (United States)

    DeFaveri, Jacquelin; Merilä, Juha

    2013-01-01

    Average age and maximum life span of breeding adult three-spined sticklebacks (Gasterosteus aculeatus) were determined in eight Fennoscandian localities with the aid of skeletochronology. The average age varied from 1.8 to 3.6 years, and maximum life span from three to six years depending on the locality. On average, fish from marine populations were significantly older than those from freshwater populations, but variation within habitat types was large. We also found significant differences in mean body size among different habitat types and populations, but only the population differences remained significant after accounting for variation due to age effects. These results show that generation length and longevity in three-spined sticklebacks can vary significantly from one locality to another, and that population differences in mean body size cannot be explained as a simple consequence of differences in population age structure. We also describe a nanistic population from northern Finland exhibiting long life span and small body size.

  2. Variation in age and size in Fennoscandian three-spined sticklebacks (Gasterosteus aculeatus.

    Directory of Open Access Journals (Sweden)

    Jacquelin DeFaveri

    Full Text Available Average age and maximum life span of breeding adult three-spined sticklebacks (Gasterosteus aculeatus were determined in eight Fennoscandian localities with the aid of skeletochronology. The average age varied from 1.8 to 3.6 years, and maximum life span from three to six years depending on the locality. On average, fish from marine populations were significantly older than those from freshwater populations, but variation within habitat types was large. We also found significant differences in mean body size among different habitat types and populations, but only the population differences remained significant after accounting for variation due to age effects. These results show that generation length and longevity in three-spined sticklebacks can vary significantly from one locality to another, and that population differences in mean body size cannot be explained as a simple consequence of differences in population age structure. We also describe a nanistic population from northern Finland exhibiting long life span and small body size.

  3. Satellite-derived SIF and CO2 Observations Show Coherent Responses to Interannual Climate Variations

    Science.gov (United States)

    Butterfield, Z.; Hogikyan, A.; Kulawik, S. S.; Keppel-Aleks, G.

    2017-12-01

    Gross primary production (GPP) is the single largest carbon flux in the Earth system, but its sensitivity to changes in climate is subject to significant uncertainty. Satellite measurements of solar-induced chlorophyll fluorescence (SIF) offer insight into spatial and temporal patterns in GPP at a global scale and, combined with other satellite-derived datasets, provide unprecedented opportunity to explore interactions between atmospheric CO2, GPP, and climate variability. To explore potential drivers of GPP in the Northern Hemisphere (NH), we compare monthly-averaged SIF data from the Global Ozone Monitoring Experiment 2 (GOME-2) with observed anomalies in temperature (T; CRU-TS), liquid water equivalent (LWE) from the Gravity Recovery and Climate Experiment (GRACE), and photosynthetically active radiation (PAR; CERES SYN1deg). Using observations from 2007 through 2015 for several NH regions, we calculate month-specific sensitivities of SIF to variability in T, LWE, and PAR. These sensitivities provide insight into the seasonal progression of how productivity is affected by climate variability and can be used to effectively model the observed SIF signal. In general, we find that high temperatures are beneficial to productivity in the spring, but detrimental in the summer. The influences of PAR and LWE are more heterogeneous between regions; for example, higher LWE in North American temperate forest leads to decreased springtime productivity, while exhibiting a contrasting effect in water-limited regions. Lastly, we assess the influence of variations in terrestrial productivity on atmospheric carbon using a new lower tropospheric CO2 product derived from the Greenhouse Gases Observing Satellite (GOSAT). Together, these data shed light on the drivers of interannual variability in the annual cycle of NH atmospheric CO2, and may provide improved constraints on projections of long-term carbon cycle responses to climate change.

  4. Determination of the Average Native Background and the Light-Induced EPR Signals and their Variation in the Teeth Enamel Based on Large-Scale Survey of the Population

    International Nuclear Information System (INIS)

    Ivannikov, Alexander I.; Khailov, Artem M.; Orlenko, Sergey P.; Skvortsov, Valeri G.; Stepanenko, Valeri F.; Zhumadilov, Kassym Sh.; Williams, Benjamin B.; Flood, Ann B.; Swartz, Harold M.

    2016-01-01

    The aim of the study is to determine the average intensity and variation of the native background signal amplitude (NSA) and of the solar light-induced signal amplitude (LSA) in electron paramagnetic resonance (EPR) spectra of tooth enamel for different kinds of teeth and different groups of people. These values are necessary for determination of the intensity of the radiation-induced signal amplitude (RSA) by subtraction of the expected NSA and LSA from the total signal amplitude measured in L-band for in vivo EPR dosimetry. Variation of these signals should be taken into account when estimating the uncertainty of the estimated RSA. A new analysis of several hundred EPR spectra that were measured earlier at X-band in a large-scale examination of the population of the Central Russia was performed. Based on this analysis, the average values and the variation (standard deviation, SD) of the amplitude of the NSA for the teeth from different positions, as well as LSA in outer enamel of the front teeth for different population groups, were determined. To convert data acquired at X-band to values corresponding to the conditions of measurement at L-band, the experimental dependencies of the intensities of the RSA, LSA and NSA on the m.w. power, measured at both X and L-band, were analysed. For the two central upper incisors, which are mainly used in in vivo dosimetry, the mean LSA annual rate induced only in the outer side enamel and its variation were obtained as 10 ± 2 (SD = 8) mGy y"-"1, the same for X- and L-bands (results are presented as the mean ± error of mean). Mean NSA in enamel and its variation for the upper incisors was calculated at 2.0 ± 0.2 (SD = 0.5) Gy, relative to the calibrated RSA dose-response to gamma radiation measured under non-power saturation conditions at X-band. Assuming the same value for L-band under non-power saturating conditions, then for in vivo measurements at L-band at 25 mW (power saturation conditions), a mean NSA and its

  5. Extensive Variation in Chromatin States Across Humans

    KAUST Repository

    Kasowski, M.

    2013-10-17

    The majority of disease-associated variants lie outside protein-coding regions, suggesting a link between variation in regulatory regions and disease predisposition. We studied differences in chromatin states using five histone modifications, cohesin, and CTCF in lymphoblastoid lines from 19 individuals of diverse ancestry. We found extensive signal variation in regulatory regions, which often switch between active and repressed states across individuals. Enhancer activity is particularly diverse among individuals, whereas gene expression remains relatively stable. Chromatin variability shows genetic inheritance in trios, correlates with genetic variation and population divergence, and is associated with disruptions of transcription factor binding motifs. Overall, our results provide insights into chromatin variation among humans.

  6. Extensive Variation in Chromatin States Across Humans

    KAUST Repository

    Kasowski, M.; Kyriazopoulou-Panagiotopoulou, S.; Grubert, F.; Zaugg, J. B.; Kundaje, A.; Liu, Y.; Boyle, A. P.; Zhang, Q. C.; Zakharia, F.; Spacek, D. V.; Li, J.; Xie, D.; Olarerin-George, A.; Steinmetz, L. M.; Hogenesch, J. B.; Kellis, M.; Batzoglou, S.; Snyder, M.

    2013-01-01

    The majority of disease-associated variants lie outside protein-coding regions, suggesting a link between variation in regulatory regions and disease predisposition. We studied differences in chromatin states using five histone modifications, cohesin, and CTCF in lymphoblastoid lines from 19 individuals of diverse ancestry. We found extensive signal variation in regulatory regions, which often switch between active and repressed states across individuals. Enhancer activity is particularly diverse among individuals, whereas gene expression remains relatively stable. Chromatin variability shows genetic inheritance in trios, correlates with genetic variation and population divergence, and is associated with disruptions of transcription factor binding motifs. Overall, our results provide insights into chromatin variation among humans.

  7. Variation in the costs of delivering routine immunization services in Peru.

    Science.gov (United States)

    Walker, D; Mosqueira, N R; Penny, M E; Lanata, C F; Clark, A D; Sanderson, C F B; Fox-Rushby, J A

    2004-09-01

    Estimates of vaccination costs usually provide only point estimates at national level with no information on cost variation. In practice, however, such information is necessary for programme managers. This paper presents information on the variations in costs of delivering routine immunization services in three diverse districts of Peru: Ayacucho (a mountainous area), San Martin (a jungle area) and Lima (a coastal area). We consider the impact of variability on predictions of cost and reflect on the likely impact on expected cost-effectiveness ratios, policy decisions and future research practice. All costs are in 2002 prices in US dollars and include the costs of providing vaccination services incurred by 19 government health facilities during the January-December 2002 financial year. Vaccine wastage rates have been estimated using stock records. The cost per fully vaccinated child ranged from 16.63-24.52 U.S. Dollars in Ayacucho, 21.79-36.69 U.S. Dollars in San Martin and 9.58-20.31 U.S. Dollars in Lima. The volume of vaccines administered and wastage rates are determinants of the variation in costs of delivering routine immunization services. This study shows there is considerable variation in the costs of providing vaccines across geographical regions and different types of facilities. Information on how costs vary can be used as a basis from which to generalize to other settings and provide more accurate estimates for decision-makers who do not have disaggregated data on local costs. Future studies should include sufficiently large sample sizes and ensure that regions are carefully selected in order to maximize the interpretation of cost variation.

  8. Variation of nuclear radii in the drip line regions

    CERN Document Server

    Beiner, M; Mas, D

    1976-01-01

    The authors are concerned with predictions of the energy density method with respect to the nuclear sizes (RMS radii). It is known that the commonly accepted A/sup 1/3/-type laws are only approximative and deviations are expected to grow significantly as one goes away from the beta -stability region. Particular attention is paid to the variation of nuclear radii in the drip line regions. Implications of the resulting large total Coulomb energy variations between neighbouring nuclei will be emphasized.

  9. Variation in Women's Preferences Regarding Male Facial Masculinity Is Better Explained by Genetic Differences Than by Previously Identified Context-Dependent Effects.

    Science.gov (United States)

    Zietsch, Brendan P; Lee, Anthony J; Sherlock, James M; Jern, Patrick

    2015-09-01

    Women's preferences for masculine versus feminine male faces are highly variable. According to a dominant theory in evolutionary psychology, this variability results from adaptations that optimize preferences by calibrating them to certain contextual factors, including women's self-perceived attractiveness, short- versus long-term relationship orientation, pathogen disgust sensitivity, and stage of the menstrual cycle. The theory does not account for the possible contribution of genetic variation on women's facial masculinity preference. Using a large sample (N = 2,160) of identical and nonidentical female Finnish twins and their siblings, we showed that the proportion of variation in women's preferences regarding male facial masculinity that was attributable to genetic variation (38%) dwarfed the variation due to the combined effect of contextual factors (< 1%). These findings cast doubt on the importance of these context-dependent effects and may suggest a need for refocusing in the field toward understanding the wide genetic variation in these preferences and how this variation relates to the evolution of sexual dimorphism in faces. © The Author(s) 2015.

  10. Early Paleogene Orbital Variations in Atmospheric CO2 and New Astronomical Solutions

    Science.gov (United States)

    Zeebe, R. E.

    2017-12-01

    Geologic records across the globe show prominent variations on orbital time scales during numerous epochs going back hundreds of millions of years. The origin of the Milankovic cycles are variations in orbital parameters of the bodies of the Solar System. On long time scales, the orbital variations can not be computed analytically because of the chaotic nature of the Solar System. Thus, numerical solutions are used to estimate changes in, e.g., Earth's orbital parameters in the past. The orbital solutions represent the backbone of cyclostratigraphy and astrochronology, now widely used in geology and paleoclimatology. Hitherto only two solutions for Earth's eccentricity appear to be used in paleoclimate studies, provided by two different groups that integrated the full Solar System equations over the past >100 Myr. In this presentation, I will touch on the basic physics behind, and present new results of, accurate Solar System integrations for Earth's eccentricity over the past hundred million years. I will discuss various limitations within the framework of the present simulations and compare the results to existing solutions. Furthermore, I will present new results from practical applications of such orbital solutions, including effects of orbital forcing on coupled climate- and carbon cycle variations. For instance, we have recently revealed a mechanism for a large lag between changes in carbon isotope ratios and eccentricity at the 400-kyr period, which has been observed in Paleocene, Oligocene, and Miocene sections. Finally, I will present the first estimates of orbital-scale variations in atmospheric CO2 during the early Paleogene.

  11. Investigation of GICs Associated with Large dB/dt Variations in Space

    Science.gov (United States)

    Dimitrakoudis, S.; Mann, I. R.; Murphy, K. R.; Rae, J.; Denton, M.; Milling, D. K.

    2016-12-01

    Geomagnetically induced currents (GICs) can be driven in terrestrial electrical power grids as a result of the induced electric fields arising from magnetic field changes driven in the coupled magnetosphere-ionosphere-ground system. Substorms are often hypothesised to be associated with the largest GIC effects on the ground, especially at higher latitudes. However, recent studies have suggested that other dayside phenomena such as sudden impulses and even ULF wave trains might also drive significant GICs. Using data from the CARISMA ground-based magnetometer network we examine the GIC response driven from a variety of magnetospheric processes. In particular we focus on events where large dB/dt is observed in-situ on GOES East and West satellites. Auroras, resulting from magnetospheric substorms, give us a dynamical view of sudden destabilizations in the nightside magnetosphere, of large spatial and temporal extent, that can drive large and potentially damaging geomagnetically induced currents (GICs) in terrestrial power grids. Since ground dB/dt can be used as a GIC proxy, we have surveyed GOES data since 2011 for the largest dB/dT events, and found some to be of the order of hundreds of nT in the span of a few seconds. These are observed in both the nightside and dayside, and, as such, we seek to establish connections to drivers affecting both sides of the terminator; tail activations and substorms on the nightside, large amplitude ULF waves, solar wind sudden impulses, and rapid changes in MIC current systems on the dayside. The short duration of these events, coupled with the use of conjugate satellite measurements and ground magnetometer arrays when possible, allows us to investigate their localization and the latitudinal extent of their effects and to further examine the potential role of non-substorm phenomena in generating GICs which may have adverse impacts in electrical power grids.

  12. Intraspecific variation in social organization by genetic variation, developmental plasticity, social flexibility or entirely extrinsic factors.

    Science.gov (United States)

    Schradin, Carsten

    2013-05-19

    Previously, it was widely believed that each species has a specific social organization, but we know now that many species show intraspecific variation in their social organization. Four different processes can lead to intraspecific variation in social organization: (i) genetic variation between individuals owing to local adaptation (between populations) or evolutionarily stable strategies within populations; (ii) developmental plasticity evolved in long-term (more than one generation) unpredictable and short-term (one generation) predictable environments, which is mediated by organizational physiological effects during early ontogeny; (iii) social flexibility evolved in highly unpredictable environments, which is mediated by activational physiological effects in adults; (iv) entirely extrinsic factors such as the death of a dominant breeder. Variation in social behaviour occurs between individuals in the case of genetic variation and developmental plasticity, but within individuals in the case of social flexibility. It is important to study intraspecific variation in social organization to understand the social systems of species because it reveals the mechanisms by which species can adapt to changing environments, offers a useful tool to study the ultimate and proximate causes of sociality, and is an interesting phenomenon by itself that needs scientific explanation.

  13. Heuristic Relative Entropy Principles with Complex Measures: Large-Degree Asymptotics of a Family of Multi-variate Normal Random Polynomials

    Science.gov (United States)

    Kiessling, Michael Karl-Heinz

    2017-10-01

    Let z\\in C, let σ ^2>0 be a variance, and for N\\in N define the integrals E_N^{}(z;σ ) := {1/σ } \\int _R\\ (x^2+z^2) e^{-{1/2σ^2 x^2}}{√{2π }}/dx \\quad if N=1, {1/σ } \\int _{R^N} \\prod \\prod \\limits _{1≤ k1. These are expected values of the polynomials P_N^{}(z)=\\prod _{1≤ n≤ N}(X_n^2+z^2) whose 2 N zeros ± i X_k^{}_{k=1,\\ldots ,N} are generated by N identically distributed multi-variate mean-zero normal random variables {X_k}N_{k=1} with co-variance {Cov}_N^{}(X_k,X_l)=(1+σ ^2-1/N)δ _{k,l}+σ ^2-1/N(1-δ _{k,l}). The E_N^{}(z;σ ) are polynomials in z^2, explicitly computable for arbitrary N, yet a list of the first three E_N^{}(z;σ ) shows that the expressions become unwieldy already for moderate N—unless σ = 1, in which case E_N^{}(z;1) = (1+z^2)^N for all z\\in C and N\\in N. (Incidentally, commonly available computer algebra evaluates the integrals E_N^{}(z;σ ) only for N up to a dozen, due to memory constraints). Asymptotic evaluations are needed for the large- N regime. For general complex z these have traditionally been limited to analytic expansion techniques; several rigorous results are proved for complex z near 0. Yet if z\\in R one can also compute this "infinite-degree" limit with the help of the familiar relative entropy principle for probability measures; a rigorous proof of this fact is supplied. Computer algebra-generated evidence is presented in support of a conjecture that a generalization of the relative entropy principle to signed or complex measures governs the N→ ∞ asymptotics of the regime iz\\in R. Potential generalizations, in particular to point vortex ensembles and the prescribed Gauss curvature problem, and to random matrix ensembles, are emphasized.

  14. Large-D gravity and low-D strings.

    Science.gov (United States)

    Emparan, Roberto; Grumiller, Daniel; Tanabe, Kentaro

    2013-06-21

    We show that in the limit of a large number of dimensions a wide class of nonextremal neutral black holes has a universal near-horizon limit. The limiting geometry is the two-dimensional black hole of string theory with a two-dimensional target space. Its conformal symmetry explains the properties of massless scalars found recently in the large-D limit. For black branes with string charges, the near-horizon geometry is that of the three-dimensional black strings of Horne and Horowitz. The analogies between the α' expansion in string theory and the large-D expansion in gravity suggest a possible effective string description of the large-D limit of black holes. We comment on applications to several subjects, in particular to the problem of critical collapse.

  15. Boreal and temperate trees show strong acclimation of respiration to warming.

    Science.gov (United States)

    Reich, Peter B; Sendall, Kerrie M; Stefanski, Artur; Wei, Xiaorong; Rich, Roy L; Montgomery, Rebecca A

    2016-03-31

    Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release, and hence further atmospheric warming. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate warming in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental warming and seasonal temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental warming and seasonal temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate warming may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.

  16. Family matters: effect of host plant variation in chemical and mechanical defenses on a sequestering specialist herbivore.

    Science.gov (United States)

    Dimarco, Romina D; Nice, Chris C; Fordyce, James A

    2012-11-01

    Insect herbivores contend with various plant traits that are presumed to function as feeding deterrents. Paradoxically, some specialist insect herbivores might benefit from some of these plant traits, for example by sequestering plant chemical defenses that herbivores then use as their own defense against natural enemies. Larvae of the butterfly species Battus philenor (L.) (Papilionidae) sequester toxic alkaloids (aristolochic acids) from their Aristolochia host plants, rendering larvae and adults unpalatable to a broad range of predators. We studied the importance of two putative defensive traits in Aristolochia erecta: leaf toughness and aristolochic acid content, and we examined the effect of intra- and interplant chemical variation on the chemical phenotype of B. philenor larvae. It has been proposed that genetic variation for sequestration ability is "invisible to natural selection" because intra- and interindividual variation in host-plant chemistry will largely eliminate a role for herbivore genetic variation in determining an herbivore's chemical phenotype. We found substantial intra- and interplant variation in leaf toughness and in the aristolochic acid chemistry in A. erecta. Based on field observations and laboratory experiments, we showed that first-instar larvae preferentially fed on less tough, younger leaves and avoided tougher, older leaves, and we found no evidence that aristolochic acid content influenced first-instar larval foraging. We found that the majority of variation in the amount of aristolochic acid sequestered by larvae was explained by larval family, not by host-plant aristolochic acid content. Heritable variation for sequestration is the predominant determinant of larval, and likely adult, chemical phenotype. This study shows that for these highly specialized herbivores that sequester chemical defenses, traits that offer mechanical resistance, such as leaf toughness, might be more important determinants of early-instar larval

  17. A systematic review of medical practice variation in OECD countries.

    Science.gov (United States)

    Corallo, Ashley N; Croxford, Ruth; Goodman, David C; Bryan, Elisabeth L; Srivastava, Divya; Stukel, Therese A

    2014-01-01

    Major variations in medical practice have been documented internationally. Variations raise questions about the quality, equity, and efficiency of resource allocation and use, and have important implications for health care and health policy. To perform a systematic review of the peer-reviewed literature on medical practice variations in OECD countries. We searched MEDLINE to find publications on medical practice variations in OECD countries published between 2000 and 2011. We present an overview of the characteristics of published studies as well as the magnitude of variations for select high impact conditions. A total of 836 studies were included. Consistent with the gray literature, there were large variations across regions, hospitals and physician practices for almost every condition and procedure studied. Many studies focused on high-impact conditions, but very few looked at the causes or outcomes of medical practice variations. While there were an overwhelming number of publications on medical practice variations the coverage was broad and not often based on a theoretical construct. Future studies should focus on conditions and procedures that are clinically important, policy relevant, resource intensive, and have high levels of public awareness. Further study of the causes and consequences of variations is important. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. Magnitude determination for large underground nuclear explosions

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Lawrence D [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-15

    A method is presented for determining the local magnitudes for large underground nuclear explosions. The Gutenberg-Richter nomograph is applied to the peak amplitudes for 24 large underground nuclear explosions that took place in Nevada. The amplitudes were measured at 18 California Wood-Anderson stations located 150-810 km from the explosion epicenter. The variation of the individual station magnitudes and magnitude corrections and the variation of the average and rms error estimates in the magnitude determinations are examined with respect to distance, azimuth, and event location. The magnitude prediction capability of the Gutenberg-Richter nomograph is examined on the basis of these two criteria, and certain corrections are suggested. The azimuthal dependence of the individual station magnitudes is investigated, and corrections for the California stations are calculated. Statistical weighting schemes for two-component data are employed, and the assumptions and limitations in the use of peak amplitudes are discussed. (author)

  19. Variation in the isotopic content of precipitation with altitude

    International Nuclear Information System (INIS)

    Stowhas, L.; Silva, C.; Moser, H.; Stichler, W.

    1975-03-01

    Monthly precipitation and single storms have been collected during three years at 12 stations along a W-E profile in Chile, going from Juan Fernandez Islands to Valparaiso, Santiago and Infiernillo in the Andes, and analysed for their deuterium content. The deltaD values are correlated with the altitude of the station, the mean temperature - which also largely depends on the altitude - and the distance from the sea. The correlation parameters show however important variations from year to year and even more from month to month. For instance, in the stretch Santiago (520 m a.s.l.) - La Parva (2680 m) the mean isotopic gradient with altitude were: -1.84 deltaD per mil/100 m in 1970, -1.09 in 1971 and -2.0 in 1972. The low value observed in 1971 could be a consequence of the peculiar weather characteristics of this unusually dry year. In the stretch from the coast to Santiago the trend of the isotopic composition of precipitation is more complicated, because the so-called continental effect is superimposed to the altitude effect. The deuterium content variations have been also determined in snowpack profiles at La Parva station. The results show that snow melting occurs slowly at the bottom during the whole winter, at the expenses of the heat stored during summer in the soil. The melting of the surface snow layers only starts at the end of the winter and then proceeds very fast

  20. Piotron at SIN - a large superconducting double torus spectrometer

    International Nuclear Information System (INIS)

    Horvath, I.; Vecsey, G.; Zellweger, J.

    1981-01-01

    A test facility for radiation therapy with negative /pi/-mesons was constructed in Switzerland. The facility is a large double torus spectrometer similar to the Stanford design. For variation of stopping depth different momenta are selected by variation of the magnetic field. Superconducting ac magnets are necessary for tumor scanning and represent a major part of such a facility. Main design features and performance are reported. 10 refs

  1. COELIAC TRUNK BRANCHING PATTERN AND VARIATION

    Directory of Open Access Journals (Sweden)

    Jude Jose Thomson

    2017-01-01

    Full Text Available BACKGROUND Anatomical variations involving the visceral arteries are common. However, variations in coeliac trunk are usually asymptomatic, they may become important in patients undergoing diagnostic angiography for gastrointestinal bleeding or prior to an operative procedure. This study was useful for knowing the possible morphological variations before an upper abdominal surgery. MATERIALS AND METHODS This was a descriptive study done by cadaveric dissection, conducted on thirty cadavers. The coeliac trunk being examined for its origin, branching pattern, distribution, and variations. Results were statistically analysed and compared with the previous studies. RESULTS In our study, 60% of the coeliac trunk shows variations and 40% have normal branching pattern. A complete absence of coeliac trunk was observed in one case. In the present study the Right inferior phrenic artery arising from coeliac trunk in 2 cases (6.6% and left inferior phrenic artery arising from coeliac trunk in 3 cases (9.9%. Both inferior phrenic arteries are arising from coeliac trunk in 2 cases (6.6%. The common hepatomesenteric trunk and gastro splenic trunk was found in 1 case (3.3%. Hepatosplenic trunk was found in 2 cases (6.6%. In another 2 cases (6.6% gastric and hepatic artery originate from coeliac trunk but splenic artery has a separate origin from abdominal aorta. An absent trunk was also found in 1 case (3.3%. In 5 cases (16.7% showed trifurcation with variation in the branching pattern. CONCLUSION The branching pattern and extreme degree variability in coeliac trunk as brought out in the observations of the present study make it obvious that the present study almost falls in description with previous studies.

  2. The clinical importance of the anatomic variations in the paranasal sinuses

    International Nuclear Information System (INIS)

    Teixeira Junior, Francisco Ribeiro; Bretas, Elisa Almeida Sathler; Madeira, Ivana Andrade; Diniz, Renata Furletti; Ribeiro, Marcelo Almeida; Motta, Emilia Guerra Pinto Coelho; Moreira, Wanderval

    2008-01-01

    The anatomic variations of the paranasal sinuses are common findings. The importance of such variations predisposing disease through the obstruction of the drainage pathway has been discussed by several authors, although it is not yet a matter of agreement. The literature was reviewed and a iconographic assay was prepared aiming the discussion of the importance of the main anatomic variations of the paranasal sinuses. The prevalence of anatomic variations of the paranasal sinuses varies largely amongst studies and its role in sinus disease is controversial. In this article, it is described the different variations associated to paranasal disease and how they relate to pathologic conditions. Most studies confirm the concept that anatomic variations of the paranasal sinuses are related to disease when they obstruct the drainage pathways. The knowledge of such alterations and its relations to pathologic conditions is expected from the general radiologist. (author)

  3. Frequency variations of discrete cranial traits in major human populations. I. Supernumerary ossicle variations.

    Science.gov (United States)

    Hanihara, T; Ishida, H

    2001-06-01

    Four supernumerary ossicle variations-the ossicle at the lambda, the parietal notch bone, the asterionic bone, and the occipitomastoid bone-were examined for laterality differences, intertrait correlations, sex differences, and between group variations in the samples from around the world. Significant laterality differences were not detected in almost all samples. In some pairs of traits, significant association of occurrence were found. Several geographic samples were sexually dimorphic with respect to the asterionic bone and to a lesser extent for the parietal notch bone. East/Northeast Asians including the Arctic populations in general had lower frequencies of the 4 accessory ossicles. Australians, Melanesians and the majority of the New World peoples, on the other hand, generally had high frequencies. In the western hemisphere of the Old World, Subsaharan Africans had relatively high frequencies. Except for the ossicle at the lambda, the distribution pattern in incidence showed clinal variation from south to north. Any identifiable adaptive value related to environmental or subsistence factors may be expressed in such clinal variation. This may allow us to hypothesise that not only mechanical factors but a founder effect, genetic drift, and population structure could have been the underlying causes for interregional variation and possible clines in the incidences of the accessory ossicles.

  4. Characteristics of seasonal variation and solar activity dependence of the geomagnetic solar quiet daily variation

    Science.gov (United States)

    Shinbori, A.; Koyama, Y.; Nose, M.; Hori, T.

    2017-12-01

    Characteristics of seasonal variation and solar activity dependence of the X- and Y-components of the geomagnetic solar quiet (Sq) daily variation at Memanbetsu in mid-latitudes and Guam near the equator have been investigated using long-term geomagnetic field data with 1-h time resolution from 1957 to 2016. In this analysis, we defined the quiet day when the maximum value of the Kp index is less than 3 for that day. In this analysis, we used the monthly average of the adjusted daily F10.7 corresponding to geomagnetically quiet days. For identification of the monthly mean Sq variation in the X and Y components (Sq-X and Sq-Y), we first determined the baseline of the X and Y components from the average value from 22 to 2 h (LT: local time) for each quiet day. Next, we calculated a deviation from the baseline of the X- and Y-components of the geomagnetic field for each quiet day, and computed the monthly mean value of the deviation for each local time. As a result, Sq-X and Sq-Y shows a clear seasonal variation and solar activity dependence. The amplitude of seasonal variation increases significantly during high solar activities, and is proportional to the solar F10.7 index. The pattern of the seasonal variation is quite different between Sq-X and Sq-Y. The result of the correlation analysis between the solar F10.7 index and Sq-X and Sq-Y shows almost the linear relationship, but the slope and intercept of the linear fitted line varies as function of local time and month. This implies that the sensitivity of Sq-X and Sq-Y to the solar activity is different for different local times and seasons. The local time dependence of the offset value of Sq-Y at Guam and its seasonal variation suggest a magnetic field produced by inter-hemispheric field-aligned currents (FACs). From the sign of the offset value of Sq-Y, it is infer that the inter-hemispheric FACs flow from the summer to winter hemispheres in the dawn and dusk sectors and from the winter to summer hemispheres in

  5. Spatiotemporal variation of surface shortwave forcing from fire-induced albedo change in interior Alaska

    Science.gov (United States)

    Huang, Shengli; Dahal, Devendra; Liu, Heping; Jin, Suming; Young, Claudia J.; Liu, Shuang; Liu, Shu-Guang

    2015-01-01

    The albedo change caused by both fires and subsequent succession is spatially heterogeneous, leading to the need to assess the spatiotemporal variation of surface shortwave forcing (SSF) as a component to quantify the climate impacts of high-latitude fires. We used an image reconstruction approach to compare postfire albedo with the albedo assuming fires had not occurred. Combining the fire-caused albedo change from the 2001-2010 fires in interior Alaska and the monthly surface incoming solar radiation, we examined the spatiotemporal variation of SSF in the early successional stage of around 10 years. Our results showed that while postfire albedo generally increased in fall, winter, and spring, some burned areas could show an albedo decrease during these seasons. In summer, the albedo increased for several years and then declined again. The spring SSF distribution did not show a latitudinal decrease from south to north as previously reported. The results also indicated that although the SSF is usually largely negative in the early successional years, it may not be significant during the first postfire year. The annual 2005-2010 SSF for the 2004 fire scars was -1.30, -4.40, -3.31, -4.00, -3.42, and -2.47 Wm-2. The integrated annual SSF map showed significant spatial variation with a mean of -3.15 Wm-2 and a standard deviation of 3.26 Wm-2, 16% of burned areas having positive SSF. Our results suggest that boreal deciduous fires would be less positive for climate change than boreal evergreen fires. Future research is needed to comprehensively investigate the spatiotemporal radiative and non-radiative forcings to determine the effect of boreal fires on climate.

  6. Variation in radon exhalation from the ground on the active fault in Kobe

    Energy Technology Data Exchange (ETDEWEB)

    Yasuoka, Y.; Shinogi, M. [Kobe Pharmaceutical Univ., Kobe, Hyogo (Japan)

    1998-12-31

    Since 27 January 1997, the measurements of radon (Rn-222) exhaled from the ground have been made continuously by the use of PICO-RAD detector (Packard instrument Co.) at monitoring stations on Ashiya active fault. The fault may have been slipped by the Kobe earthquake (magnitude 7.2, 17 January 1995). The variation of relative radon exhalation on the fault was large. We guessed the large variation of relative radon exhalation on the fault was caused by not only the influence of meteorology but also the influence of other factors. (author)

  7. Body weight in relation to variation in body size of Oystercatchers Haematopus ostralegus

    NARCIS (Netherlands)

    Zwarts, L; Hulscher, JB; Koopman, K; Zegers, PM

    1996-01-01

    This paper analyses the relationships between body weight in the Oystercatcher and two measures of its body size, bill length and wing length. The weight variation between individuals due to differences in body size is nearly as large as the seasonal variation in body weight within individuals. Wing

  8. Cosmological constants and variations

    International Nuclear Information System (INIS)

    Barrow, John D

    2005-01-01

    We review properties of theories for the variation of the gravitation and fine structure 'constants'. We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that is consistent with time-variation in the fine structure 'constant' since a redshift of 3.5. The behaviour of a simple class of varying alpha cosmologies is outlined in the light of all the observational constraints. We also discuss some of the consequences of varying 'constants' for oscillating universes and show by means of exact solutions that they appear to evolve monotonically in time even though the scale factor of the universe oscillates

  9. Comparison of seasonal variation between anthropogenic and natural emission inventory and Satellite observation in Southeast Asia

    Science.gov (United States)

    Kurata, G.; Lalitaporn, P.

    2012-12-01

    Since the economic growth of the countries in Southeast Asia is significantly rapid, the emission of air pollutant from the anthropogenic activity, such as industry, power generation and transportation is rapidly increasing. Moreover, biomass burning due to unsuitable agricultural management, deforestation and expansion of farmland are discharging large amount of pollutants, such as Carbon monoxide, volatile organic compound and particulate matter. Especially, the particulate matter from biomass burning causes the serious haze pollution in surrounding area in Southeast Asia. Furthermore, the biomass fuel used for cooking at residential sector discharges harmful pollutants including a particulate matter, and causes the adverse health impact to people on indoor and outdoor. In this study, we evaluated the spatial distribution and the seasonal variation of emission inventory for Southeast Asia region by comparing with satellite observation data in order to improve the accuracy of the impact assessment of air pollution by regional atmospheric chemistry transport model (WRF and CMAQ). As an emission inventory data, we used our original regional emission inventory for Southeast Asia region developed from detail transportation and industry data sets as well as a several existing emission inventories. As satellite observation data, the vertical column density of NO2, Particulate matter and Carbon monoxide obtained by various satellite, such as GOME, GOME2, SCIAMACY, OMI and so on. As a result of comparisons between satellite observation and emission inventories from 1996 to 2011, in the case of anthropogenic emission, seasonal variation was comparatively well in agreement with the seasonal variation of satellite data. However, the uncertainty of the seasonal variation was large on several large cities. In the case of emission from biomass burning, the seasonal variation was clear, but inter-annual variation was also large due to large scale climate condition.

  10. Variation tolerant SoC design

    Science.gov (United States)

    Kozhikkottu, Vivek J.

    performance distribution. This task is particularly complex and challenging due to the inter-dependencies between components' execution, indirect effects of shared resources, and interactions between multiple system-level "execution paths". We argue that accurate variation-aware performance analysis requires Monte-Carlo based repeated system execution. Our proposed analysis framework leverages emulation to significantly speedup performance analysis without sacrificing the generality and accuracy achieved by Monte-Carlo based simulations. Our experiments show performance improvements of around 60x compared to state-of-the-art hardware-software co-simulation tools and also underscore the framework's potential to enable variation-aware design and exploration at the system level. Our second contribution addresses the problem of designing variation-tolerant SoCs using recovery based design, a popular circuit design paradigm that addresses variations by eliminating guard-bands and operating circuits at close to "zero margins" while detecting and recovering from timing errors. While previous efforts have demonstrated the potential benefits of recovery based design, we identify several challenges that need to be addressed in order to apply this technique to SoCs. We present a systematic design framework to apply recovery based design at the system level. We propose to partition SoCs into "recovery islands", wherein each recovery island consists of one or more SoC components that can recover independent of the rest of the SoC. We present a variation-aware design methodology that partitions a given SoC into recovery islands and computes the optimal operating points for each island, taking into account the various trade-offs involved. Our experiments demonstrate that the proposed design framework achieves an average of 32% energy savings over conventional worst-case designs, with negligible losses in performance. The third contribution of this thesis introduces disproportionate

  11. The impact of nectar chemical features on phenotypic variation in two related nectar yeasts.

    Science.gov (United States)

    Pozo, María I; Herrera, Carlos M; Van den Ende, Wim; Verstrepen, Kevin; Lievens, Bart; Jacquemyn, Hans

    2015-06-01

    Floral nectars become easily colonized by microbes, most often species of the ascomycetous yeast genus Metschnikowia. Although it is known that nectar composition can vary tremendously among plant species, most probably corresponding to the nutritional requirements of their main pollinators, far less is known about how variation in nectar chemistry affects intraspecific variation in nectarivorous yeasts. Because variation in nectar traits probably affects growth and abundance of nectar yeasts, nectar yeasts can be expected to display large phenotypic variation in order to cope with varying nectar conditions. To test this hypothesis, we related variation in the phenotypic landscape of a vast collection of nectar-living yeast isolates from two Metschnikowia species (M. reukaufii and M. gruessii) to nectar chemical traits using non-linear redundancy analyses. Nectar yeasts were collected from 19 plant species from different plant families to include as much variation in nectar chemical traits as possible. As expected, nectar yeasts displayed large variation in phenotypic traits, particularly in traits related to growth performance in carbon sources and inhibitors, which was significantly related to the host plant from which they were isolated. Total sugar concentration and relative fructose content significantly explained the observed variation in the phenotypic profile of the investigated yeast species, indicating that sugar concentration and composition are the key traits that affect phenotypic variation in nectarivorous yeasts. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Policy implications for improved cook stove programs—A case study of the importance of village fuel use variations

    International Nuclear Information System (INIS)

    Vahlne, Niklas; Ahlgren, Erik O.

    2014-01-01

    Despite the long history of cook stove programs, very few have been successful, often only in areas where biomass is purchased or there is a biomass shortage. Several studies have described how rural households generally rely on several different fuels; which fuels are used may depend on various household characteristics such as location and income. This article explores possible consequences of variations in fuel usage for improved cook stove programs and how this may vary between different areas. Reductions of CO 2 equivalent emissions and monetary savings are calculated for hypothetical cook stove deployment using data from a rural energy survey in the Vĩnh Phúc province of northern Vietnam. The results indicate that the areas may respond differently to the various stove options, both in terms of economy and emission reductions. Furthermore, there are large differences in emission reduction calculations when only Kyoto-gases are included and when non-Kyoto greenhouse agents are added. Assumptions regarding household behavior and stove efficiencies have large impacts on the results, indicating a need for further research on how improved cook stoves may influence households’ fuel choices. - Highlights: • Household data from six different villages were used to calculate potential benefits from an improved stove program. • The possible monetary savings and reductions in CO 2 equivalent emissions were calculated. • The results show benefits as non-linear functions of stove improvements. • The results show large variations among villages in the functions mapping stove improvements to benefits

  13. Cycle-by-cycle variations in a spark ignition engine fueled with natural gas-hydrogen blends combined with EGR

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Bin; Hu, Erjiang; Huang, Zuohua; Zheng, Jianjun; Liu, Bing; Jiang, Deming [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, 710049 Xi' an (China)

    2009-10-15

    Study of cycle-by-cycle variations in a spark ignition engine fueled with natural gas-hydrogen blends combined with exhaust gas recirculation (EGR) was conducted. The effects of EGR ratio and hydrogen fraction on engine cycle-by-cycle variations are analyzed. The results show that the cylinder peak pressure, the maximum rate of pressure rise and the indicated mean effective pressure decrease and cycle-by-cycle variations increase with the increase of EGR ratio. Interdependency between the above parameters and their corresponding crank angles of cylinder peak pressure is decreased with the increase of EGR ratio. For a given EGR ratio, combustion stability is promoted and cycle-by-cycle variations are decreased with the increase of hydrogen fraction in the fuel blends. Non-linear relationship is presented between the indicated mean effective pressure and EGR ratio. Slight influence of EGR ratio on indicated mean effective pressure is observed at low EGR ratios while large influence of EGR ratio on indicated mean effective pressure is demonstrated at high EGR ratios. The high test engine speed has lower cycle-by-cycle variations due to the enhancement of air flow turbulence and swirls in the cylinder. Increasing hydrogen fraction can maintain low cycle-by-cycle variations at high EGR ratios. (author)

  14. Outdoor radon variation in Romania

    International Nuclear Information System (INIS)

    Simion, Elena; Simion, Florin

    2008-01-01

    Full text: The results of a long-term survey (1992 - 2006) of the variations of outdoor radon concentrations in semi-natural location from Romania are reported in the present paper. Measurements, covering between two and four sessions of the day (morning, afternoon, evening and night), were performed on a daily bases by 37 Environmental Radioactivity Monitoring Stations from National Environmental Radioactivity Survey Network. The method used was based on indirect determination of outdoor radon from aerosol samples collected on glass micro-fibre filters by drawing the air through the filters. The sampling was performed in a fixed place at a height of 2 m above the ground surface. Total beta counting of aerosol samples collected was performed immediately and after 20 hours. Values recorded during the years of continuous measurement indicated the presence of several patterns in the long-term variation of outdoor radon concentration: diurnal, seasonal and annual variation. For diurnal variation, outdoor radon concentration shows a maximum values in the night (early hours) and minimum values by day (in the afternoon). On average, this maximum is a factor of 2 higher than the minimum. Late autumn - beginning of winter maximum and an early spring minimum are characteristic for seasonal patterns. In the long term a seasonal pattern was observed for diurnal variation, with an average diurnal maximum to minimum ratio of 1.33 in winter compared with 3.0 in the summer months. The variations of outdoor radon levels showed little correlation with the uranium concentration of the ground and were attributed to changes in soil moisture content. In dry seasons, because of the low precipitation, the soil was drying out in the summer allowing fractures to develop and radon to migrate easily through the ground. Depending on micro-climatic and geological conditions, outdoor radon average concentrations in different regions of Romania are from 1200 mBq/mc to 13065 mBq/mc. The smallest

  15. Genetic variation in adaptability and pleiotropy in budding yeast.

    Science.gov (United States)

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

    2017-08-17

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

  16. Seasonal variations of indoor radon concentrations

    International Nuclear Information System (INIS)

    Majborn, B.

    1990-01-01

    Seasonal variations of indoor radon concentrations have been studied in a cluster of 10 single-family houses. Eight of the houses are of a similar construction with slab-on-grade foundations. The remaining two houses have different substructures, one of them having a crawl space, and the other having partly a basement and partly a crawl space. A 'normal' seasonal variation of the radon concentration with a maximum in winter and a minimum in summer was observed in most of the houses. In these houses the variation showed a strong correlation with the indoor-outdoor temperature difference on a 2-month basis. However, deviating seasonal variations were observed in some of the houses, notably in the two houses having different substructures. This paper reports that a re-examination of the data obtained in a previous study indicates that winter/summer ratios of indoor radon concentrations in Danish houses depend on the house substructure. The mean winter/summer ratios were about 2.1 for houses with slab-on-grade foundations, 1.5 for houses having a basement, and 1.0 for houses with a crawl space (geometric mean values). However, a study with more houses in each substructure category will be needed to show whether or not the indicated differences are generally valid for Danish houses

  17. Mate-finding as an overlooked critical determinant of dispersal variation in sexually-reproducing animals.

    Science.gov (United States)

    Gilroy, James J; Lockwood, Julie L

    2012-01-01

    Dispersal is a critically important process in ecology, but robust predictive models of animal dispersal remain elusive. We identify a potentially ubiquitous component of variation in animal dispersal that has been largely overlooked until now: the influence of mate encounters on settlement probability. We use an individual-based model to simulate dispersal in sexually-reproducing organisms that follow a simple set of movement rules based on conspecific encounters, within an environment lacking spatial habitat heterogeneity. We show that dispersal distances vary dramatically with fluctuations in population density in such a model, even in the absence of variation in dispersive traits between individuals. In a simple random-walk model with promiscuous mating, dispersal distributions become increasingly 'fat-tailed' at low population densities due to the increasing scarcity of mates. Similar variation arises in models incorporating territoriality. In a model with polygynous mating, we show that patterns of sex-biased dispersal can even be reversed across a gradient of population density, despite underlying dispersal mechanisms remaining unchanged. We show that some widespread dispersal patterns found in nature (e.g. fat tailed distributions) can arise as a result of demographic variability in the absence of heterogeneity in dispersive traits across the population. This implies that models in which individual dispersal distances are considered to be fixed traits might be unrealistic, as dispersal distances vary widely under a single dispersal mechanism when settlement is influenced by mate encounters. Mechanistic models offer a promising means of advancing our understanding of dispersal in sexually-reproducing organisms.

  18. Experiments and Large-Eddy Simulations of acoustically forced bluff-body flows

    Energy Technology Data Exchange (ETDEWEB)

    Ayache, S.; Dawson, J.R.; Triantafyllidis, A. [Department of Engineering, University of Cambridge (United Kingdom); Balachandran, R. [Department of Mechanical Engineering, University College London (United Kingdom); Mastorakos, E., E-mail: em257@eng.cam.ac.u [Department of Engineering, University of Cambridge (United Kingdom)

    2010-10-15

    The isothermal air flow behind an enclosed axisymmetric bluff body, with the incoming flow being forced by a loudspeaker at a single frequency and with large amplitude, has been explored with high data-rate Laser-Doppler Anemometry measurements and Large-Eddy Simulations. The comparison between experiment and simulations allows a quantification of the accuracy of LES for turbulent flows with periodicity and the results provide insights into the structure of flows relevant to combustors undergoing self-excited oscillations. At low forcing frequencies, the whole flow pulsates with the incoming flow, although at a phase lag that depends on spatial location. At high forcing frequencies, vortices are shed from the bluff body and the recirculation zone, as a whole, pulsates less. Despite the fact that the incoming flow has an oscillation that is virtually monochromatic, the velocity spectra show peaks at various harmonics, whose relative magnitudes vary with location. A sub-harmonic peak is also observed inside the recirculation zone possibly caused by merging of the shed vortices. The phase-averaged turbulent fluctuations show large temporal and spatial variations. The LES reproduces reasonably accurately the experimental findings in terms of phase-averaged mean and r.m.s. velocities, vortex formation, and spectral peaks.

  19. Experiments and Large-Eddy Simulations of acoustically forced bluff-body flows

    International Nuclear Information System (INIS)

    Ayache, S.; Dawson, J.R.; Triantafyllidis, A.; Balachandran, R.; Mastorakos, E.

    2010-01-01

    The isothermal air flow behind an enclosed axisymmetric bluff body, with the incoming flow being forced by a loudspeaker at a single frequency and with large amplitude, has been explored with high data-rate Laser-Doppler Anemometry measurements and Large-Eddy Simulations. The comparison between experiment and simulations allows a quantification of the accuracy of LES for turbulent flows with periodicity and the results provide insights into the structure of flows relevant to combustors undergoing self-excited oscillations. At low forcing frequencies, the whole flow pulsates with the incoming flow, although at a phase lag that depends on spatial location. At high forcing frequencies, vortices are shed from the bluff body and the recirculation zone, as a whole, pulsates less. Despite the fact that the incoming flow has an oscillation that is virtually monochromatic, the velocity spectra show peaks at various harmonics, whose relative magnitudes vary with location. A sub-harmonic peak is also observed inside the recirculation zone possibly caused by merging of the shed vortices. The phase-averaged turbulent fluctuations show large temporal and spatial variations. The LES reproduces reasonably accurately the experimental findings in terms of phase-averaged mean and r.m.s. velocities, vortex formation, and spectral peaks.

  20. Variational iteration method for one dimensional nonlinear thermoelasticity

    International Nuclear Information System (INIS)

    Sweilam, N.H.; Khader, M.M.

    2007-01-01

    This paper applies the variational iteration method to solve the Cauchy problem arising in one dimensional nonlinear thermoelasticity. The advantage of this method is to overcome the difficulty of calculation of Adomian's polynomials in the Adomian's decomposition method. The numerical results of this method are compared with the exact solution of an artificial model to show the efficiency of the method. The approximate solutions show that the variational iteration method is a powerful mathematical tool for solving nonlinear problems

  1. Evaluation of within-litter birth weight variation in piglets

    African Journals Online (AJOL)

    VaZindove

    2014-03-23

    Mar 23, 2014 ... rates. Large weight variation at birth also requires the use of more pens, ... defined as the distribution of individual weights within a litter, has not been ..... the economic values of selection responses from the component traits ...

  2. Comparison of predicted and measured variations of indoor radon concentration

    International Nuclear Information System (INIS)

    Arvela, H.; Voutilainen, A.; Maekelaeinen, I.; Castren, O.; Winqvist, K.

    1988-01-01

    Prediction of the variations of indoor radon concentration were calculated using a model relating indoor radon concentration to radon entry rate, air infiltration and meteorological factors. These calculated variations have been compared with seasonal variations of 33 houses during 1-4 years, with winter-summer concentration ratios of 300 houses and the measured diurnal variation. In houses with a slab in ground contact the measured seasonal variations are quite often in agreement with variations predicted for nearly pure pressure difference driven flow. The contribution of a diffusion source is significant in houses with large porous concrete walls against the ground. Air flow due to seasonally variable thermal convection within eskers strongly affects the seasonal variations within houses located thereon. Measured and predicted winter-summer concentration ratios demonstrate that, on average, the ratio is a function of radon concentration. The ratio increases with increasing winter concentration. According to the model the diurnal maximum caused by a pressure difference driven flow occurs in the morning, a finding which is in agreement with the measurements. The model presented can be used for differentiating between factors affecting radon entry into houses. (author)

  3. Functional genomics analysis of big data identifies novel PPARy target SNPs showing association with cardio metabolic outcomes

    Science.gov (United States)

    Background - Cardiovascular disease and type-2-diabetes represent overlapping diseases where a large portion of the variation attributable to genetics remains unexplained. An important player in their etiology is Peroxisome Proliferator-activated Receptor gamma (PPARy) that is involved in lipid and ...

  4. Contrasting patterns of leaf trait variation among and within species during tropical dry forest succession in Costa Rica.

    Science.gov (United States)

    Derroire, Géraldine; Powers, Jennifer S; Hulshof, Catherine M; Cárdenas Varela, Luis E; Healey, John R

    2018-01-10

    A coordinated response to environmental drivers amongst individual functional traits is central to the plant strategy concept. However, whether the trait co-ordination observed at the global scale occurs at other ecological scales (especially within species) remains an open question. Here, for sapling communities of two tropical dry forest types in Costa Rica, we show large differences amongst traits in the relative contribution of species turnover and intraspecific variation to their directional changes in response to environmental changes along a successional gradient. We studied the response of functional traits associated with the leaf economics spectrum and drought tolerance using intensive sampling to analyse inter- and intra-specific responses to environmental changes and ontogeny. Although the overall functional composition of the sapling communities changed during succession more through species turnover than through intraspecific trait variation, their relative contributions differed greatly amongst traits. For instance, community mean specific leaf area changed mostly due to intraspecific variation. Traits of the leaf economics spectrum showed decoupled responses to environmental drivers and ontogeny. These findings emphasise how divergent ecological mechanisms combine to cause great differences in changes of individual functional traits over environmental gradients and ecological scales.

  5. Temporal Variation in Oscillatory Characteristics of Long-period Tremor at Aso Volcano, Japan.

    Science.gov (United States)

    Yamamoto, M.; Ohkura, T.; Kaneshima, S.; Kawakatsu, H.

    2017-12-01

    At Aso volcano, Japan, various kinds of volcanic signals with broad frequency contents have been observed since 1930s. One of these signals is long-period tremor (LPT) with a dominant period of around 15 s, which is intermittently emitted from the volcano regardless of the surface activity. Our broadband seismic observations have revealed that LPTs are a kind of resonance oscillation of a crack-like conduit beneath the crater. In this study, aiming to detect a temporal variation of volcanic system, we analyze the long-term variation of LPTs from 1994 to the present.We first examine the temporal variation of dominant periods of LPTs (fundamental mode of around 15 s and the first overtone of around 7 s) using the continuous data recorded at broadband stations close to the active crater. The result shows a clear temporal change in the dominant periods of LPTs in 2003-2005 and 2014-2015. In 2003-2005, the periods of the two modes show correlated temporal change, and it can be interpreted as compositional and/or thermal change of hydrothermal fluids. On the other hand, in 2014-2015, the period of first overtone is almost constant at around 8 s, while that of the fundamental mode shows relatively large temporal fluctuations between 16 s and 12 s. To explain the different behavior among the two resonant modes, we examine the oscillatory characteristics of a fluid-filled crack having linearly varying thickness. With this model, we find that the ratio between resonance periods becomes smaller than that in the case of a flat crack having constant thickness. This behavior can be understood by considering the effective thickness of the crack depends on the wavelength of each resonant mode. Based on these results, the different temporal variation of dominant periods can be interpreted by depth-dependent thickness of the crack-like conduit which may be caused by pressurization and/or intrusion of magma at deeper portion of the conduit. These results suggest the importance of

  6. Brightness Variations of Sun-like Stars: The Mystery Deepens - Astronomers facing Socratic "ignorance"

    Science.gov (United States)

    2009-12-01

    An extensive study made with ESO's Very Large Telescope deepens a long-standing mystery in the study of stars similar to the Sun. Unusual year-long variations in the brightness of about one third of all Sun-like stars during the latter stages of their lives still remain unexplained. Over the past few decades, astronomers have offered many possible explanations, but the new, painstaking observations contradict them all and only deepen the mystery. The search for a suitable interpretation is on. "Astronomers are left in the dark, and for once, we do not enjoy it," says Christine Nicholls from Mount Stromlo Observatory, Australia, lead author of a paper reporting the study. "We have obtained the most comprehensive set of observations to date for this class of Sun-like stars, and they clearly show that all the possible explanations for their unusual behaviour just fail." The mystery investigated by the team dates back to the 1930s and affects about a third of Sun-like stars in our Milky Way and other galaxies. All stars with masses similar to our Sun become, towards the end of their lives, red, cool and extremely large, just before retiring as white dwarfs. Also known as red giants, these elderly stars exhibit very strong periodic variations in their luminosity over timescales up to a couple of years. "Such variations are thought to be caused by what we call 'stellar pulsations'," says Nicholls. "Roughly speaking, the giant star swells and shrinks, becoming brighter and dimmer in a regular pattern. However, one third of these stars show an unexplained additional periodic variation, on even longer timescales - up to five years." In order to find out the origin of this secondary feature, the astronomers monitored 58 stars in our galactic neighbour, the Large Magellanic Cloud, over two and a half years. They acquired spectra using the high resolution FLAMES/GIRAFFE spectrograph on ESO's Very Large Telescope and combined them with images from other telescopes [1

  7. Variability of tropical cyclone rapid intensification in the North Atlantic and its relationship with climate variations

    Science.gov (United States)

    Wang, Chunzai; Wang, Xidong; Weisberg, Robert H.; Black, Michael L.

    2017-12-01

    The paper uses observational data from 1950 to 2014 to investigate rapid intensification (RI) variability of tropical cyclones (TCs) in the North Atlantic and its relationships with large-scale climate variations. RI is defined as a TC intensity increase of at least 15.4 m/s (30 knots) in 24 h. The seasonal RI distribution follows the seasonal TC distribution, with the highest number in September. Although an RI event can occur anywhere over the tropical North Atlantic (TNA), there are three regions of maximum RI occurrence: (1) the western TNA of 12°N-18°N and 60°W-45°W, (2) the Gulf of Mexico and the western Caribbean Sea, and (3) the open ocean southeast and east of Florida. RI events also show a minimum value in the eastern Caribbean Sea north of South America—a place called a hurricane graveyard due to atmospheric divergence and subsidence. On longer time scales, RI displays both interannual and multidecadal variability, but RI does not show a long-term trend due to global warming. The top three climate indices showing high correlations with RI are the June-November ENSO and Atlantic warm pool indices, and the January-March North Atlantic oscillation index. It is found that variabilities of vertical wind shear and TC heat potential are important for TC RI in the hurricane main development region, whereas relative humidity at 500 hPa is the main factor responsible for TC RI in the eastern TNA. However, the large-scale oceanic and atmospheric variables analyzed in this study do not show an important role in TC RI in the Gulf of Mexico and the open ocean southeast and east of Florida. This suggests that other factors such as small-scale changes of oceanic and atmospheric variables or TC internal processes may be responsible for TC RI in these two regions. Additionally, the analyses indicate that large-scale atmospheric and oceanic variables are not critical to TC genesis and formation; however, once a tropical depression forms, large-scale climate

  8. Non-invasive in-cell determination of free cytosolic [NAD+]/[NADH] ratios using hyperpolarized glucose show large variations in metabolic phenotypes

    DEFF Research Database (Denmark)

    Christensen, Caspar Elo; Karlsson, Magnus; Winther, Jakob R.

    2014-01-01

    Accumulating evidence suggest that the pyridine nucleotide NAD has far wider biological functions than its classical role in energy metabolism. NAD is used by hundreds of enzymes that catalyse substrate oxidation and as such it plays a key role in various biological processes such as aging, cell...... death and oxidative stress. It has been suggested that changes in the ratio of free cytosolic [NAD+]/[NADH] reflects metabolic alterations leading to, or correlating with, pathological states. We have designed an isotopically labelled metabolic bioprobe of free cytosolic [NAD+]/[NADH] by combining...... a magnetic enhancement technique (hyperpolarization) with cellular glycolytic activity. The bioprobe reports free cytosolic [NAD+]/[NADH] ratios based on dynamically measured in-cell [pyruvate]/ [lactate] ratios. We demonstrate its utility in breast and prostate cancer cells. The free cytosolic [NAD...

  9. Poloidal variations in toroidal fusion reactor wall power loadings

    International Nuclear Information System (INIS)

    Carroll, M.C.; Miley, G.H.

    1985-01-01

    A geometric formulation is developed by the authors for determining poloidal variations in bremmstrahlung, cyclotron radiation, and neutron wall power loadings in toroidal fusion devices. Assuming toroidal symmetry and utilizing a numerical model which partitions the plasma into small cells, it was generally found that power loadings are highest on the outer surface of the torus, although variations are not as large as some have predicted. Results are presented for various plasma power generation configurations, plasma volume fractions, and toroidal aspect ratios, and include plasma and wall blockage effects

  10. Activation of AMP-activated protein kinase in response to temperature elevation shows seasonal variation in the zebra mussel, Dreissena polymorpha.

    Science.gov (United States)

    Jost, Jennifer A; Keshwani, Sarah S; Abou-Hanna, Jacob J

    2015-04-01

    Global climate change is affecting ectothermic species, and a variety of studies are needed on thermal tolerances, especially from cellular and physiological perspectives. This study utilized AMP-activated protein kinase (AMPK), a key regulator of cellular energy levels, to examine the effects of high water temperatures on zebra mussel (Dreissena polymorpha) physiology. During heating, AMPK activity increased as water temperature increased to a point, and maximum AMPK activity was detected at high, but sublethal, water temperatures. This pattern varied with season, suggesting that cellular mechanisms of seasonal thermal acclimatization affect basic metabolic processes during sublethal heat stress. There was a greater seasonal variation in the water temperature at which maximum AMPK activity was measured than in lethal water temperature. Furthermore, baseline AMPK activity varied significantly across seasons, most likely reflecting altered metabolic states during times of growth and reproduction. In addition, when summer-collected mussels were lab-acclimated to winter and spring water temperatures, patterns of heat stress mirrored those of field-collected animals. These data suggest that water temperature is the main driver of the seasonal variation in physiology. This study concluded that AMPK activity, which reflects changes in energy supply and demand during heat stress, can serve as a sensitive and early indicator of temperature stress in mussels. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Application of the Regional Water Mass Variations from GRACE Satellite Gravimetry to Large-Scale Water Management in Africa

    Directory of Open Access Journals (Sweden)

    Guillaume Ramillien

    2014-08-01

    Full Text Available Time series of regional 2° × 2° Gravity Recovery and Climate Experiment (GRACE solutions of surface water mass change have been computed over Africa from 2003 to 2012 with a 10-day resolution by using a new regional approach. These regional maps are used to describe and quantify water mass change. The contribution of African hydrology to actual sea level rise is negative and small in magnitude (i.e., −0.1 mm/y of equivalent sea level (ESL mainly explained by the water retained in the Zambezi River basin. Analysis of the regional water mass maps is used to distinguish different zones of important water mass variations, with the exception of the dominant seasonal cycle of the African monsoon in the Sahel and Central Africa. The analysis of the regional solutions reveals the accumulation in the Okavango swamp and South Niger. It confirms the continuous depletion of water in the North Sahara aquifer at the rate of −2.3 km3/y, with a decrease in early 2008. Synergistic use of altimetry-based lake water volume with total water storage (TWS from GRACE permits a continuous monitoring of sub-surface water storage for large lake drainage areas. These different applications demonstrate the potential of the GRACE mission for the management of water resources at the regional scale.

  12. Habitat Fragmentation Differentially Affects Genetic Variation, Phenotypic Plasticity and Survival in Populations of a Gypsum Endemic

    Directory of Open Access Journals (Sweden)

    Silvia Matesanz

    2017-05-01

    Full Text Available Habitat fragmentation, i.e., fragment size and isolation, can differentially alter patterns of neutral and quantitative genetic variation, fitness and phenotypic plasticity of plant populations, but their effects have rarely been tested simultaneously. We assessed the combined effects of size and connectivity on these aspects of genetic and phenotypic variation in populations of Centaurea hyssopifolia, a narrow endemic gypsophile that previously showed performance differences associated with fragmentation. We grew 111 maternal families sampled from 10 populations that differed in their fragment size and connectivity in a common garden, and characterized quantitative genetic variation, phenotypic plasticity to drought for key functional traits, and plant survival, as a measure of population fitness. We also assessed neutral genetic variation within and among populations using eight microsatellite markers. Although C. hyssopifolia is a narrow endemic gypsophile, we found substantial neutral genetic variation and quantitative variation for key functional traits. The partition of genetic variance indicated that a higher proportion of variation was found within populations, which is also consistent with low population differentiation in molecular markers, functional traits and their plasticity. This, combined with the generally small effect of habitat fragmentation suggests that gene flow among populations is not restricted, despite large differences in fragment size and isolation. Importantly, population’s similarities in genetic variation and plasticity did not reflect the lower survival observed in isolated populations. Overall, our results indicate that, although the species consists of genetically variable populations able to express functional plasticity, such aspects of adaptive potential may not always reflect populations’ survival. Given the differential effects of habitat connectivity on functional traits, genetic variation and fitness

  13. Controlling variation in the comet assay

    Directory of Open Access Journals (Sweden)

    Andrew Richard Collins

    2014-10-01

    Full Text Available Variability of the comet assay is a serious issue, whether it occurs from experiment to experiment in the same laboratory, or between different laboratories analysing identical samples. Do we have to live with high variability, just because the comet assay is a biological assay rather than analytical chemistry? Numerous attempts have been made to limit variability by standardising the assay protocol, and the critical steps in the assay have been identified; agarose concentration, duration of alkaline incubation, and electrophoresis conditions (time, temperature and voltage gradient are particularly important. Even when these are controlled, variation seems to be inevitable. It is helpful to include in experiments reference standards, i.e. cells with a known amount of specific damage to the DNA. They can be aliquots frozen from a single large batch of cells, either untreated (negative controls or treated with, for example, H2O2 or X-rays to induce strand breaks (positive control for the basic assay, or photosensitiser plus light to oxidise guanine (positive control for Fpg- or OGG1-sensitive sites. Reference standards are especially valuable when performing a series of experiments over a long period - for example, analysing samples of white blood cells from a large human biomonitoring trial - to check that the assay is performing consistently, and to identify anomalous results necessitating a repeat experiment. The reference values of tail intensity can also be used to iron out small variations occurring from day to day. We present examples of the use of reference standards in human trials, both within one laboratory and between different laboratories, and describe procedures that can be used to control variation.

  14. Genome size variation among and within Camellia species by using flow cytometric analysis.

    Directory of Open Access Journals (Sweden)

    Hui Huang

    Full Text Available BACKGROUND: The genus Camellia, belonging to the family Theaceae, is economically important group in flowering plants. Frequent interspecific hybridization together with polyploidization has made them become taxonomically "difficult taxa". The DNA content is often used to measure genome size variation and has largely advanced our understanding of plant evolution and genome variation. The goals of this study were to investigate patterns of interspecific and intraspecific variation of DNA contents and further explore genome size evolution in a phylogenetic context of the genus. METHODOLOGY/PRINCIPAL FINDINGS: The DNA amount in the genus was determined by using propidium iodide flow cytometry analysis for a total of 139 individual plants representing almost all sections of the two subgenera, Camellia and Thea. An improved WPB buffer was proven to be suitable for the Camellia species, which was able to counteract the negative effects of secondary metabolite and generated high-quality results with low coefficient of variation values (CV <5%. Our results showed trivial effects on different tissues of flowers, leaves and buds as well as cytosolic compounds on the estimation of DNA amount. The DNA content of C. sinensis var. assamica was estimated to be 1C = 3.01 pg by flow cytometric analysis, which is equal to a genome size of about 2940 Mb. CONCLUSION: Intraspecific and interspecific variations were observed in the genus Camellia, and as expected, the latter was larger than the former. Our study suggests a directional trend of increasing genome size in the genus Camellia probably owing to the frequent polyploidization events.

  15. Moisture variation inferred from a nebkha profile correlates with vegetation changes in the southwestern Mu Us Desert of China over one century.

    Science.gov (United States)

    Li, Jinchang; Zhao, Yanfang; Han, Liuyan; Zhang, Guoming; Liu, Rentao

    2017-11-15

    We inferred moisture variations from the early 1930s to the early 2010s in the southwestern Mu Us Desert of China using Rb/Sr ratio, chemical index of alteration (CIA), and organic matter (OM) content in a nebkha profile. Our results showed that the variations in moisture may have been the main factor that controlled vegetation recovery or degradation, and we believe that gradual vegetation recovery was notable throughout the study area during the past 80years, despite two notable degradation stages during the mid-1950s and the mid-1980s. The Rb/Sr ratio, CIA, and OM content revealed that moisture levels increased during the study period, though with large interannual variations. During the early stage of nebkha formation, the moisture variations were controlled by unusually low precipitation. Thereafter, the precipitation, pan evaporation and temperature determined together moisture variations, but the key factor determining moisture variations was different during different periods. The moisture variations trend revealed in this study may not be restricted to this region as it was similar with the adjacent Mongolian Plateau. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Individual variation in the (patho)physiology of energy balance

    NARCIS (Netherlands)

    Boersma, Gretha J.; Benthem, Lambertus; van Dijk, Gertjan; Scheurink, Anton J. W.

    2011-01-01

    There are large individual differences in the susceptibility for metabolic disorders such as obesity, the metabolic syndrome and type 2 diabetes. Unfortunately, most animal studies in this field ignore the importance of individual variation which limits the face validity of these studies for

  17. On Bi-Dimensional Second µ-Variation

    Directory of Open Access Journals (Sweden)

    Ereú Jurancy

    2014-12-01

    Full Text Available In this paper, we present a generalization of the notion of bounded slope variation for functions defined on a rectangle Iba in ℝ2. Given a strictly increasing function µ-defined in a closed real interval, we introduce the class BVµ,2 (Iba , of functions of bounded second µ-variation on Iba ; and show that this class can be equipped with a norm with respect to which it is a Banach space. We also deal with the important case of factorizable functions in BVµ,2 (Iba and finally we exhibit a relation between this class and the one of double Riemann-Stieltjes integrals of functions of bi-dimensional bounded variation.

  18. Epigenetic Variation in Monozygotic Twins: A Genome-Wide Analysis of DNA Methylation in Buccal Cells

    Directory of Open Access Journals (Sweden)

    Jenny van Dongen

    2014-05-01

    Full Text Available DNA methylation is one of the most extensively studied epigenetic marks in humans. Yet, it is largely unknown what causes variation in DNA methylation between individuals. The comparison of DNA methylation profiles of monozygotic (MZ twins offers a unique experimental design to examine the extent to which such variation is related to individual-specific environmental influences and stochastic events or to familial factors (DNA sequence and shared environment. We measured genome-wide DNA methylation in buccal samples from ten MZ pairs (age 8–19 using the Illumina 450k array and examined twin correlations for methylation level at 420,921 CpGs after QC. After selecting CpGs showing the most variation in the methylation level between subjects, the mean genome-wide correlation (rho was 0.54. The correlation was higher, on average, for CpGs within CpG islands (CGIs, compared to CGI shores, shelves and non-CGI regions, particularly at hypomethylated CpGs. This finding suggests that individual-specific environmental and stochastic influences account for more variation in DNA methylation in CpG-poor regions. Our findings also indicate that it is worthwhile to examine heritable and shared environmental influences on buccal DNA methylation in larger studies that also include dizygotic twins.

  19. Simulation of Cycle-to-Cycle Variation in Dual-Fuel Engines

    KAUST Repository

    Jaasim, Mohammed; Pasunurthi, Shyamsundar; Jupudi, Ravichandra S.; Gubba, Sreenivasa Rao; Primus, Roy; Klingbeil, Adam; Wijeyakulasuriya, Sameera; Im, Hong G.

    2017-01-01

    Standard practices of internal combustion (IC) engine experiments are to conduct the measurements of quantities averaged over a large number of cycles. Depending on the operating conditions, the cycle-to-cycle variation (CCV) of quantities

  20. Mutation Rate Variation is a Primary Determinant of the Distribution of Allele Frequencies in Humans.

    Directory of Open Access Journals (Sweden)

    Arbel Harpak

    2016-12-01

    Full Text Available The site frequency spectrum (SFS has long been used to study demographic history and natural selection. Here, we extend this summary by examining the SFS conditional on the alleles found at the same site in other species. We refer to this extension as the "phylogenetically-conditioned SFS" or cSFS. Using recent large-sample data from the Exome Aggregation Consortium (ExAC, combined with primate genome sequences, we find that human variants that occurred independently in closely related primate lineages are at higher frequencies in humans than variants with parallel substitutions in more distant primates. We show that this effect is largely due to sites with elevated mutation rates causing significant departures from the widely-used infinite sites mutation model. Our analysis also suggests substantial variation in mutation rates even among mutations involving the same nucleotide changes. In summary, we show that variable mutation rates are key determinants of the SFS in humans.

  1. Computing variational bounds for flow through random aggregates of Spheres

    International Nuclear Information System (INIS)

    Berryman, J.G.

    1983-01-01

    Known formulas for variational bounds on Darcy's constant for slow flow through porous media depend on two-point and three-poiint spatial correlation functions. Certain bounds due to Prager and Doi depending only a two-point correlation functions have been calculated for the first time for random aggregates of spheres with packing fractions (eta) up to eta = 0.64. Three radial distribution functions for hard spheres were tested for eta up to 0.49: (1) the uniform distribution or ''well-stirred approximation,'' (2) the Percus Yevick approximation, and (3) the semi-empirical distribution of Verlet and Weis. The empirical radial distribution functions of Benett andd Finney were used for packing fractions near the random-close-packing limit (eta/sub RCP/dapprox.0.64). An accurate multidimensional Monte Carlo integration method (VEGAS) developed by Lepage was used to compute the required two-point correlation functions. The results show that Doi's bounds are preferred for eta>0.10 while Prager's bounds are preferred for eta>0.10. The ''upper bounds'' computed using the well-stirred approximation actually become negative (which is physically impossible) as eta increases, indicating the very limited value of this approximation. The other two choices of radial distribution function give reasonable results for eta up to 0.49. However, these bounds do not decrease with eta as fast as expected for large eta. It is concluded that variational bounds dependent on three-point correlation functions are required to obtain more accurate bounds on Darcy's constant for large eta

  2. Determination of the Average Native Background and the Light-Induced EPR Signals and their Variation in the Teeth Enamel Based on Large-Scale Survey of the Population.

    Science.gov (United States)

    Ivannikov, Alexander I; Khailov, Artem M; Orlenko, Sergey P; Skvortsov, Valeri G; Stepanenko, Valeri F; Zhumadilov, Kassym Sh; Williams, Benjamin B; Flood, Ann B; Swartz, Harold M

    2016-12-01

    The aim of the study is to determine the average intensity and variation of the native background signal amplitude (NSA) and of the solar light-induced signal amplitude (LSA) in electron paramagnetic resonance (EPR) spectra of tooth enamel for different kinds of teeth and different groups of people. These values are necessary for determination of the intensity of the radiation-induced signal amplitude (RSA) by subtraction of the expected NSA and LSA from the total signal amplitude measured in L-band for in vivo EPR dosimetry. Variation of these signals should be taken into account when estimating the uncertainty of the estimated RSA. A new analysis of several hundred EPR spectra that were measured earlier at X-band in a large-scale examination of the population of the Central Russia was performed. Based on this analysis, the average values and the variation (standard deviation, SD) of the amplitude of the NSA for the teeth from different positions, as well as LSA in outer enamel of the front teeth for different population groups, were determined. To convert data acquired at X-band to values corresponding to the conditions of measurement at L-band, the experimental dependencies of the intensities of the RSA, LSA and NSA on the m.w. power, measured at both X and L-band, were analysed. For the two central upper incisors, which are mainly used in in vivo dosimetry, the mean LSA annual rate induced only in the outer side enamel and its variation were obtained as 10 ± 2 (SD = 8) mGy y -1 , the same for X- and L-bands (results are presented as the mean ± error of mean). Mean NSA in enamel and its variation for the upper incisors was calculated at 2.0 ± 0.2 (SD = 0.5) Gy, relative to the calibrated RSA dose-response to gamma radiation measured under non-power saturation conditions at X-band. Assuming the same value for L-band under non-power saturating conditions, then for in vivo measurements at L-band at 25 mW (power saturation conditions), a mean NSA and its

  3. Planning tiger recovery: Understanding intraspecific variation for effective conservation

    Science.gov (United States)

    Wilting, Andreas; Courtiol, Alexandre; Christiansen, Per; Niedballa, Jürgen; Scharf, Anne K.; Orlando, Ludovic; Balkenhol, Niko; Hofer, Heribert; Kramer-Schadt, Stephanie; Fickel, Jörns; Kitchener, Andrew C.

    2015-01-01

    Although significantly more money is spent on the conservation of tigers than on any other threatened species, today only 3200 to 3600 tigers roam the forests of Asia, occupying only 7% of their historical range. Despite the global significance of and interest in tiger conservation, global approaches to plan tiger recovery are partly impeded by the lack of a consensus on the number of tiger subspecies or management units, because a comprehensive analysis of tiger variation is lacking. We analyzed variation among all nine putative tiger subspecies, using extensive data sets of several traits [morphological (craniodental and pelage), ecological, molecular]. Our analyses revealed little variation and large overlaps in each trait among putative subspecies, and molecular data showed extremely low diversity because of a severe Late Pleistocene population decline. Our results support recognition of only two subspecies: the Sunda tiger, Panthera tigris sondaica, and the continental tiger, Panthera tigris tigris, which consists of two (northern and southern) management units. Conservation management programs, such as captive breeding, reintroduction initiatives, or trans-boundary projects, rely on a durable, consistent characterization of subspecies as taxonomic units, defined by robust multiple lines of scientific evidence rather than single traits or ad hoc descriptions of one or few specimens. Our multiple-trait data set supports a fundamental rethinking of the conventional tiger taxonomy paradigm, which will have profound implications for the management of in situ and ex situ tiger populations and boost conservation efforts by facilitating a pragmatic approach to tiger conservation management worldwide. PMID:26601191

  4. A multi-perspective view of genetic variation in Cameroon.

    Science.gov (United States)

    Coia, V; Brisighelli, F; Donati, F; Pascali, V; Boschi, I; Luiselli, D; Battaggia, C; Batini, C; Taglioli, L; Cruciani, F; Paoli, G; Capelli, C; Spedini, G; Destro-Bisol, G

    2009-11-01

    In this study, we report the genetic variation of autosomal and Y-chromosomal microsatellites in a large Cameroon population dataset (a total of 11 populations) and jointly analyze novel and previous genetic data (mitochondrial DNA and protein coding loci) taking geographic and cultural factors into consideration. The complex pattern of genetic variation of Cameroon can in part be described by contrasting two geographic areas (corresponding to the northern and southern part of the country), which differ substantially in environmental, biological, and cultural aspects. Northern Cameroon populations show a greater within- and among-group diversity, a finding that reflects the complex migratory patterns and the linguistic heterogeneity of this area. A striking reduction of Y-chromosomal genetic diversity was observed in some populations of the northern part of the country (Podokwo and Uldeme), a result that seems to be related to their demographic history rather than to sampling issues. By exploring patterns of genetic, geographic, and linguistic variation, we detect a preferential correlation between genetics and geography for mtDNA. This finding could reflect a female matrimonial mobility that is less constrained by linguistic factors than in males. Finally, we apply the island model to mitochondrial and Y-chromosomal data and obtain a female-to-male migration Nnu ratio that was more than double in the northern part of the country. The combined effect of the propensity to inter-populational admixture of females, favored by cultural contacts, and of genetic drift acting on Y-chromosomal diversity could account for the peculiar genetic pattern observed in northern Cameroon.

  5. Planning tiger recovery: Understanding intraspecific variation for effective conservation.

    Science.gov (United States)

    Wilting, Andreas; Courtiol, Alexandre; Christiansen, Per; Niedballa, Jürgen; Scharf, Anne K; Orlando, Ludovic; Balkenhol, Niko; Hofer, Heribert; Kramer-Schadt, Stephanie; Fickel, Jörns; Kitchener, Andrew C

    2015-06-01

    Although significantly more money is spent on the conservation of tigers than on any other threatened species, today only 3200 to 3600 tigers roam the forests of Asia, occupying only 7% of their historical range. Despite the global significance of and interest in tiger conservation, global approaches to plan tiger recovery are partly impeded by the lack of a consensus on the number of tiger subspecies or management units, because a comprehensive analysis of tiger variation is lacking. We analyzed variation among all nine putative tiger subspecies, using extensive data sets of several traits [morphological (craniodental and pelage), ecological, molecular]. Our analyses revealed little variation and large overlaps in each trait among putative subspecies, and molecular data showed extremely low diversity because of a severe Late Pleistocene population decline. Our results support recognition of only two subspecies: the Sunda tiger, Panthera tigris sondaica, and the continental tiger, Panthera tigris tigris, which consists of two (northern and southern) management units. Conservation management programs, such as captive breeding, reintroduction initiatives, or trans-boundary projects, rely on a durable, consistent characterization of subspecies as taxonomic units, defined by robust multiple lines of scientific evidence rather than single traits or ad hoc descriptions of one or few specimens. Our multiple-trait data set supports a fundamental rethinking of the conventional tiger taxonomy paradigm, which will have profound implications for the management of in situ and ex situ tiger populations and boost conservation efforts by facilitating a pragmatic approach to tiger conservation management worldwide.

  6. Variations in {sup 123}I-metaiodobenzylguanidine (MIBG) late heart mediastinal ratios in chronic heart failure: a need for standardisation and validation

    Energy Technology Data Exchange (ETDEWEB)

    Verberne, Hein J. [University of Amsterdam, Department of Nuclear Medicine, Academic Medical Center, Amsterdam (Netherlands); Academic Medical Center, F2-238, Department of Nuclear Medicine, P.O.Box 22700, Amsterdam (Netherlands); Habraken, Jan B.A.; Eck-Smit, Berthe L.F. van [University of Amsterdam, Department of Nuclear Medicine, Academic Medical Center, Amsterdam (Netherlands); Agostini, Denis [CHU Cote de Nacre, Department of Nuclear Medicine, Caen (France); Jacobson, Arnold F. [GE Healthcare, Princeton, NJ (United States)

    2008-03-15

    There is lack of validation and standardisation of acquisition parameters for myocardial {sup 123}I-metaiodobenzylguanidine (MIBG). This lack of standardisation hampers large scale implementation of {sup 123}I-MIBG parameters in the evaluation of patients with chronic heart failure (CHF). In a retrospective multi-centre study {sup 123}I-MIBG planar scintigrams obtained on 290 CHF patients (82% male; 58% dilated cardiomyopathy; New York Heart Association [NYHA classification] > I) were reanalysed to determine the late heart-to-mediastinum ratio (H/M). There was a large variation in acquisition parameters. Multivariate forward stepwise regression showed that a significant proportion (31%, p < 0.001) of the variation in late H/M could be explained by a model containing patient-related variables and acquisition parameters. Left ventricular ejection fraction (p < 0.001), type of collimation (p < 0.001), acquisition duration (p = 0.001), NYHA class (p = 0.028) and age (p = 0.034) were independent predictors of late H/M. Acquisitions parameters are independent contributors to the variation of semi-quantitative measurements of cardiac {sup 123}I-MIBG uptake. Improved standardisation of cardiac {sup 123}I-MIBG imaging parameters would contribute to increased clinical applicability for this procedure. (orig.)

  7. Studies on the Colour Variation in Larvae of Ephestia kuhniella (ZELLER)(Lepidoptera, Phycitidae) : 1. On the Inheritance of colour variation

    OpenAIRE

    Osamu, IMURA; Entomology Laboratory, National Food Research Institute

    1980-01-01

    The crossing experiment and the selection experiment were carried out at 25℃ and 67% r.h. to define genetic mechanisms of the colour variation in larvae of Ephestia kuhniella. The populations sampled from the Wild-type stock showed the wide range of continuous colour variation from white to deep pink in the 5th inster lavae. The results of the crossing experiment between white larval strain and red larval strain selected from the Wild-type stock suggested the larval colour variation was a qua...

  8. Variation as a main feature of norm

    Directory of Open Access Journals (Sweden)

    S. Poladova

    2017-09-01

    Full Text Available The past half-century has witnessed remarkable growth in the study of language variation, and it has now become a highly productive subfield of research in sociolinguistics. Variability is everywhere in language, from the unique details in each production of a sound or sign to the auditory or visual processing of the linguistic signal. All languages that we can observe today show variation; what is more, they vary in identical ways, namely geographically and socially. It’s no secret that languages like English are full of variation. So, the aim of the article is to detect the reasons of variation and to uncover rates of usage of different free variations for a given set of lexical items. The research work is carried out by using the descriptive, comparative methods by subjecting to analysis the specific language materials. The discovery of law of variation became a starting point for the evolution of linguistics. The problem of search of variation facts and its role in the functioning of language system concerns many specialists from the outset. The scope of the investigation was to set up a system out of chaos of phenomena. Currently, the fact of conditionality of variation by system relations existing in the language is considered to be established.

  9. Precise colocalization of interacting structural and pigmentary elements generates extensive color pattern variation in Phelsuma lizards

    Science.gov (United States)

    2013-01-01

    Background Color traits in animals play crucial roles in thermoregulation, photoprotection, camouflage, and visual communication, and are amenable to objective quantification and modeling. However, the extensive variation in non-melanic pigments and structural colors in squamate reptiles has been largely disregarded. Here, we used an integrated approach to investigate the morphological basis and physical mechanisms generating variation in color traits in tropical day geckos of the genus Phelsuma. Results Combining histology, optics, mass spectrometry, and UV and Raman spectroscopy, we found that the extensive variation in color patterns within and among Phelsuma species is generated by complex interactions between, on the one hand, chromatophores containing yellow/red pteridine pigments and, on the other hand, iridophores producing structural color by constructive interference of light with guanine nanocrystals. More specifically, we show that 1) the hue of the vivid dorsolateral skin is modulated both by variation in geometry of structural, highly ordered narrowband reflectors, and by the presence of yellow pigments, and 2) that the reflectivity of the white belly and of dorsolateral pigmentary red marks, is increased by underlying structural disorganized broadband reflectors. Most importantly, these interactions require precise colocalization of yellow and red chromatophores with different types of iridophores, characterized by ordered and disordered nanocrystals, respectively. We validated these results through numerical simulations combining pigmentary components with a multilayer interferential optical model. Finally, we show that melanophores form dark lateral patterns but do not significantly contribute to variation in blue/green or red coloration, and that changes in the pH or redox state of pigments provide yet another source of color variation in squamates. Conclusions Precisely colocalized interacting pigmentary and structural elements generate extensive

  10. Dynamics of nonholonomic systems from variational principles embedded variation identity

    International Nuclear Information System (INIS)

    Guo Yongxin; Liu Shixing; Liu Chang; Chang Peng

    2009-01-01

    Nondeterminacy of dynamics, i.e., the nonholonomic or the vakonomic, fundamental variational principles, e.g., the Lagrange-d'Alembert or Hamiltonian, and variational operators, etc., of nonholonomic mechanical systems can be attributed to the non-uniqueness of ways how to realize nonholonomic constraints. Making use of a variation identity of nonholonomic constraints embedded into the Hamilton's principle with the method of Lagrange undetermined multipliers, three kinds of dynamics for the nonholonomic systems including the vakonomic and nonholonomic ones and a new one are obtained if the variation is respectively reduced to three conditional variations: vakonomic variation, Hoelder's variation and Suslov's variation, defined by the identity. Therefore, different dynamics of nonholonomic systems can be derived from an integral variational principle, utilizing one way of embedding constraints into the principle, with different variations. It is verified that the similar embedding of the identity into the Lagrange-d'Alembert principle gives rise to the nonholonomic dynamics but fails to give the vakonomic one unless the constraints are integrable.

  11. Variation in the cost of care for primary total knee arthroplasties

    Directory of Open Access Journals (Sweden)

    Derek A. Haas, MBA

    2017-03-01

    Conclusions: The large variation in costs among sites suggests major and multiple opportunities to transfer knowledge about process and productivity improvements that lower costs while simultaneously maintaining or improving outcomes.

  12. Seasonal Variation in Epidemiology

    Science.gov (United States)

    Marrero, Osvaldo

    2013-01-01

    Seasonality analyses are important in medical research. If the incidence of a disease shows a seasonal pattern, then an environmental factor must be considered in its etiology. We discuss a method for the simultaneous analysis of seasonal variation in multiple groups. The nuts and bolts are explained using simple trigonometry, an elementary…

  13. Temporal variations in metabolic and autotrophic indices for Acropora digitifera and Acropora spicifera--implications for monitoring projects.

    Science.gov (United States)

    Hinrichs, Saskia; Patten, Nicole L; Waite, Anya M

    2013-01-01

    Coral health indices are important components of the management assessments of coral reefs, providing insight into local variation in reef condition, as well as tools for comparisons between reefs and across various time scales. Understanding how such health indices vary in space and time is critical to their successful implementation as management tools. Here we compare autotrophic and heterotrophic coral health indices, examining specifically the temporal variation driven by the local environmental variation, at three scales (diel, daily and seasonal). We compared metabolic indices (RNA/DNA ratio, protein concentration) and autotrophic indices (Chlorophyll a (Chl a), zooxanthellae density, effective quantum yield (yield) and relative electron transport rate (rETR)) for two dominant Acropora species, A. digitifera and A. spicifera at Ningaloo Reef (north-western Australia) in August 2010 (austral winter) and February 2011 (austral summer). Clear seasonal patterns were documented for metabolic indices, zooxanthellae density and rETR, while cyclic diel patterns only occurred for yield and rETR, and RNA/DNA ratio. Significant daily variation was observed for RNA/DNA ratio, Chl a concentration, yield and rETR. Results suggest that zooxanthellae density and protein concentrations are good long-term indicators of coral health whose variance is largely seasonal, while RNA/DNA ratio and rETR can be used for both long-term (seasonal) and short-term (diel) coral monitoring. Chl a can be used to describe changes between days and yield for both diel and daily variations. Correlations between health indices and light history showed that short-term changes in irradiance had the strongest impact on all health indices except zooxanthellae density for A. digitifera; for A. spicifera no correlation was observed at all. However, cumulative irradiance over the several days before sampling showed significant correlations with most health indices suggesting that a time-lag effect has

  14. Collective frequency variation in network synchronization and reverse PageRank.

    Science.gov (United States)

    Skardal, Per Sebastian; Taylor, Dane; Sun, Jie; Arenas, Alex

    2016-04-01

    A wide range of natural and engineered phenomena rely on large networks of interacting units to reach a dynamical consensus state where the system collectively operates. Here we study the dynamics of self-organizing systems and show that for generic directed networks the collective frequency of the ensemble is not the same as the mean of the individuals' natural frequencies. Specifically, we show that the collective frequency equals a weighted average of the natural frequencies, where the weights are given by an outflow centrality measure that is equivalent to a reverse PageRank centrality. Our findings uncover an intricate dependence of the collective frequency on both the structural directedness and dynamical heterogeneity of the network, and also reveal an unexplored connection between synchronization and PageRank, which opens the possibility of applying PageRank optimization to synchronization. Finally, we demonstrate the presence of collective frequency variation in real-world networks by considering the UK and Scandinavian power grids.

  15. Collective frequency variation in network synchronization and reverse PageRank

    Science.gov (United States)

    Skardal, Per Sebastian; Taylor, Dane; Sun, Jie; Arenas, Alex

    2016-04-01

    A wide range of natural and engineered phenomena rely on large networks of interacting units to reach a dynamical consensus state where the system collectively operates. Here we study the dynamics of self-organizing systems and show that for generic directed networks the collective frequency of the ensemble is not the same as the mean of the individuals' natural frequencies. Specifically, we show that the collective frequency equals a weighted average of the natural frequencies, where the weights are given by an outflow centrality measure that is equivalent to a reverse PageRank centrality. Our findings uncover an intricate dependence of the collective frequency on both the structural directedness and dynamical heterogeneity of the network, and also reveal an unexplored connection between synchronization and PageRank, which opens the possibility of applying PageRank optimization to synchronization. Finally, we demonstrate the presence of collective frequency variation in real-world networks by considering the UK and Scandinavian power grids.

  16. Coupled variations of fundamental couplings and primordial nucleosynthesis

    International Nuclear Information System (INIS)

    Coc, Alain; Nunes, Nelson J.; Olive, Keith A.; Uzan, Jean-Philippe; Vangioni, Elisabeth

    2006-10-01

    The effect of variations of the fundamental nuclear parameters on big-bang nucleosynthesis are modeled and discussed in detail taking into account the interrelations between the fundamental parameters arising in unified theories. Considering only 4 He, strong constraints on the variation of the neutron lifetime, neutron-proton mass difference are set. These constraints are then translated into constraints on the time variation of the Yukawa couplings and the fine structure constant. Furthermore, we show that a variation of the deuterium binding energy is able to reconcile the 7 Li abundance deduced from the WMAP analysis with its spectroscopically determined value while maintaining concordance with D and 4 He. (authors)

  17. Regularization of Nonmonotone Variational Inequalities

    International Nuclear Information System (INIS)

    Konnov, Igor V.; Ali, M.S.S.; Mazurkevich, E.O.

    2006-01-01

    In this paper we extend the Tikhonov-Browder regularization scheme from monotone to rather a general class of nonmonotone multivalued variational inequalities. We show that their convergence conditions hold for some classes of perfectly and nonperfectly competitive economic equilibrium problems

  18. Environment and host as large-scale controls of ectomycorrhizal fungi.

    Science.gov (United States)

    van der Linde, Sietse; Suz, Laura M; Orme, C David L; Cox, Filipa; Andreae, Henning; Asi, Endla; Atkinson, Bonnie; Benham, Sue; Carroll, Christopher; Cools, Nathalie; De Vos, Bruno; Dietrich, Hans-Peter; Eichhorn, Johannes; Gehrmann, Joachim; Grebenc, Tine; Gweon, Hyun S; Hansen, Karin; Jacob, Frank; Kristöfel, Ferdinand; Lech, Paweł; Manninger, Miklós; Martin, Jan; Meesenburg, Henning; Merilä, Päivi; Nicolas, Manuel; Pavlenda, Pavel; Rautio, Pasi; Schaub, Marcus; Schröck, Hans-Werner; Seidling, Walter; Šrámek, Vít; Thimonier, Anne; Thomsen, Iben Margrete; Titeux, Hugues; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Waldner, Peter; Wijk, Sture; Zhang, Yuxin; Žlindra, Daniel; Bidartondo, Martin I

    2018-06-06

    Explaining the large-scale diversity of soil organisms that drive biogeochemical processes-and their responses to environmental change-is critical. However, identifying consistent drivers of belowground diversity and abundance for some soil organisms at large spatial scales remains problematic. Here we investigate a major guild, the ectomycorrhizal fungi, across European forests at a spatial scale and resolution that is-to our knowledge-unprecedented, to explore key biotic and abiotic predictors of ectomycorrhizal diversity and to identify dominant responses and thresholds for change across complex environmental gradients. We show the effect of 38 host, environment, climate and geographical variables on ectomycorrhizal diversity, and define thresholds of community change for key variables. We quantify host specificity and reveal plasticity in functional traits involved in soil foraging across gradients. We conclude that environmental and host factors explain most of the variation in ectomycorrhizal diversity, that the environmental thresholds used as major ecosystem assessment tools need adjustment and that the importance of belowground specificity and plasticity has previously been underappreciated.

  19. Thermophysical characteristics of the large main-belt asteroid (349) Dembowska

    Science.gov (United States)

    Yu, Liang Liang; Yang, Bin; Ji, Jianghui; Ip, Wing-Huen

    2017-12-01

    (349) Dembowska is a large, bright main-belt asteroid that has a fast rotation and an oblique spin axis. It might have experienced partial melting and differentiation. We constrain Dembowska's thermophysical properties, such as thermal inertia, roughness fraction, geometric albedo and effective diameter within 3σ uncertainty of Γ =20^{+12}_{-7} Jm-2 s-0.5 K-1, f_r=0.25^{+0.60}_{-0.25}, p_v=0.309^{+0.026}_{-0.038} and D_eff=155.8^{+7.5}_{-6.2} km, by utilizing the advanced thermophysical model to analyse four sets of thermal infrared data obtained by the Infrared Astronomy Satellite (IRAS), AKARI, the Wide-field Infrared Survey Explorer (WISE) and the Subaru/Cooled Mid-Infrared Camera and Spectrometer (COMICS) at different epochs. In addition, by modelling the thermal light curve observed by WISE, we obtain the rotational phases of each data set. These rotationally resolved data do not reveal significant variations of thermal inertia and roughness across the surface, indicating that the surface of Dembowska should be covered by a dusty regolith layer with few rocks or boulders. Besides, the low thermal inertia of Dembowska shows no significant difference with other asteroids larger than 100 km, which indicates that the dynamical lives of these large asteroids are long enough to make their surfaces have sufficiently low thermal inertia. Furthermore, based on the derived surface thermophysical properties, as well as the known orbital and rotational parameters, we can simulate Dembowska's surface and subsurface temperatures throughout its orbital period. The surface temperature varies from ∼40 to ∼220 K, showing significant seasonal variation, whereas the subsurface temperature achieves equilibrium temperature about 120-160 K below a depth of 30-50 cm.

  20. Intraspecific variation in 137Cs activity concentration in sporocarps of Suillus variegatus in seven Swedish populations

    International Nuclear Information System (INIS)

    Dahlberg, Anders; Nikolova, Ivanka; Johanson, K.-J.

    1997-01-01

    Following the Chernobyl accident in 1986, sporocarps of Suillus variegatus in Sweden showed a large amount of individual variation in concentration of 137 Cs activity. Our aim was to determine the degrees to which this variability in sporocarp 137 Cs levels could be explained by differences between (i) local populations, (ii) fungal genets and (iii) locations within genets. Five populations in a 100-yr-old Scots pine forest, located within a 1 km 2 area, and two populations in Scots pine/Norway spruce forest, located 40 km north-west of Uppsala, were investigated. In total, 154 sporocarps were analysed to determine their 137 Cs content. Of these, the genetic affiliations of 86 were successfully characterized using somatic incompatibility reactions. Twenty-six genets were found which, on average, consisted of 6.5 sporocarps. The genets averaged 7.5 m in size, measured as the length between the most distant sporocarps. The mean sporocarp 137 Cs level was 67.1 ± 2.8 kBq kgsup(-1) D.W. (range between 13.6 and 182). According to analyses of variance, within-population variation accounted for 60% of the total variation in 137 Cs levels, while 40% was ascribed to variation among populations. Within a population, 137 Cs levels did not generally differ significantly between genets. Plausible reasons for intraspecific variation in radiocaesium content in sporocarps are discussed. (author)

  1. Morphological and allozyme variation in a collection of Lagenaria siceraria (Molina Standl. from Côte d'Ivoire

    Directory of Open Access Journals (Sweden)

    Koffi KK.

    2009-01-01

    Full Text Available This study describes the intraspecific variation of 30 edible-seed Lagenaria siceraria germplasm accessions from the University of Abobo-Adjamé. These accessions were collected from three (Centre, East and South geographical zones of Côte d’Ivoire. Selection based on seed size by the farmers has resulted in subdividing the species into two cultivars: large-seeded and smallseeded. The morphological diversity study of the collection included 18 accessions and 24 traits. The multivariate analysis of variance (MANOVA showed a significant difference between the two groups of cultivars. Principal component analysis on 13 traits pointed out variations among individuals, mainly on the basis of flower, fruit, and seed size. Dendrogram with UPGMA method allowed clustering of the cultivars. The genetic structure analysis among accessions using allozyme markers showed the following values: 18.95% for the proportion of polymorphic loci (P, 1.21 for the number of alleles (A and 0.053 for observed heterozygosity (Ho. The level of the within accessions genetic diversity (HS = 0.188 was higher than the genetic variation among accessions (DST = 0.082. The estimates of F-statistics indicated a low level of genetic differentiation between accessions (FST = 0.298. Such a value suggested that L. siceraria maintains about 30% of its genetic variation among accessions. Nei genetic distances between the two cultivars were also low (0.002, indicating that cultivars were genetically similar enough to belong to the same genetic group.

  2. VELOCITY VARIATIONS IN THE PHOENIX–HERMUS STAR STREAM

    Energy Technology Data Exchange (ETDEWEB)

    Carlberg, R. G. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Grillmair, C. J., E-mail: carlberg@astro.utoronto.ca, E-mail: carl@ipac.caltech.edu [Spitzer Science Center, 1200 E. California Blvd., Pasadena, CA 91125 (United States)

    2016-10-20

    Measurements of velocity and density perturbations along stellar streams in the Milky Way provide a time-integrated measure of dark matter substructure at larger galactic radius than the complementary instantaneous inner-halo strong lensing detection of dark matter sub-halos in distant galaxies. An interesting case to consider is the proposed Phoenix–Hermus star stream, which is long, thin, and on a nearly circular orbit, making it a particular good target to study for velocity variations along its length. In the presence of dark matter sub-halos, the stream velocities are significantly perturbed in a manner that is readily understood with the impulse approximation. A set of simulations shows that only sub-halos above a few 10{sup 7} M {sub ⊙} lead to reasonably long-lived observationally detectable velocity variations of amplitude of order 1 km s{sup −1}, with an average of about one visible hit per (two-armed) stream over a 3 Gyr interval. An implication is that globular clusters themselves will not have a visible impact on the stream. Radial velocities have the benefit of being completely insensitive to distance errors. Distance errors scatter individual star velocities perpendicular and tangential to the mean orbit, but their mean values remain unbiased. Calculations like these help build the quantitative case to acquire large, fairly deep, precision velocity samples of stream stars.

  3. Quark mass variation constraints from Big Bang nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Bedaque, P; Luu, T; Platter, L

    2010-12-13

    We study the impact on the primordial abundances of light elements created of a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN). In order to navigate through the particle and nuclear physics required to connect quark masses to binding energies and reaction rates in a model-independent way we use lattice QCD data and an hierarchy of effective field theories. We find that the measured {sup 4}He abundances put a bound of {delta}-1% {approx}< m{sub q}/m{sub 1} {approx}< 0.7%. The effect of quark mass variations on the deuterium abundances can be largely compensated by changes of the baryon-to-photon ratio {eta}. Including the bounds on the variation of {eta} coming from WMAP results and some additional assumptions narrows the range of allowed values of {delta}m{sub q}/m{sub q} somewhat.

  4. Branch xylem density variations across the Amazon Basin

    Science.gov (United States)

    Patiño, S.; Lloyd, J.; Paiva, R.; Baker, T. R.; Quesada, C. A.; Mercado, L. M.; Schmerler, J.; Schwarz, M.; Santos, A. J. B.; Aguilar, A.; Czimczik, C. I.; Gallo, J.; Horna, V.; Hoyos, E. J.; Jimenez, E. M.; Palomino, W.; Peacock, J.; Peña-Cruz, A.; Sarmiento, C.; Sota, A.; Turriago, J. D.; Villanueva, B.; Vitzthum, P.; Alvarez, E.; Arroyo, L.; Baraloto, C.; Bonal, D.; Chave, J.; Costa, A. C. L.; Herrera, R.; Higuchi, N.; Killeen, T.; Leal, E.; Luizão, F.; Meir, P.; Monteagudo, A.; Neil, D.; Núñez-Vargas, P.; Peñuela, M. C.; Pitman, N.; Priante Filho, N.; Prieto, A.; Panfil, S. N.; Rudas, A.; Salomão, R.; Silva, N.; Silveira, M.; Soares Dealmeida, S.; Torres-Lezama, A.; Vásquez-Martínez, R.; Vieira, I.; Malhi, Y.; Phillips, O. L.

    2009-04-01

    Xylem density is a physical property of wood that varies between individuals, species and environments. It reflects the physiological strategies of trees that lead to growth, survival and reproduction. Measurements of branch xylem density, ρx, were made for 1653 trees representing 598 species, sampled from 87 sites across the Amazon basin. Measured values ranged from 218 kg m-3 for a Cordia sagotii (Boraginaceae) from Mountagne de Tortue, French Guiana to 1130 kg m-3 for an Aiouea sp. (Lauraceae) from Caxiuana, Central Pará, Brazil. Analysis of variance showed significant differences in average ρx across regions and sampled plots as well as significant differences between families, genera and species. A partitioning of the total variance in the dataset showed that species identity (family, genera and species) accounted for 33% with environment (geographic location and plot) accounting for an additional 26%; the remaining "residual" variance accounted for 41% of the total variance. Variations in plot means, were, however, not only accountable by differences in species composition because xylem density of the most widely distributed species in our dataset varied systematically from plot to plot. Thus, as well as having a genetic component, branch xylem density is a plastic trait that, for any given species, varies according to where the tree is growing in a predictable manner. Within the analysed taxa, exceptions to this general rule seem to be pioneer species belonging for example to the Urticaceae whose branch xylem density is more constrained than most species sampled in this study. These patterns of variation of branch xylem density across Amazonia suggest a large functional diversity amongst Amazonian trees which is not well understood.

  5. Partitioning of genetic variation between regulatory and coding gene segments: the predominance of software variation in genes encoding introvert proteins.

    Science.gov (United States)

    Mitchison, A

    1997-01-01

    In considering genetic variation in eukaryotes, a fundamental distinction can be made between variation in regulatory (software) and coding (hardware) gene segments. For quantitative traits the bulk of variation, particularly that near the population mean, appears to reside in regulatory segments. The main exceptions to this rule concern proteins which handle extrinsic substances, here termed extrovert proteins. The immune system includes an unusually large proportion of this exceptional category, but even so its chief source of variation may well be polymorphism in regulatory gene segments. The main evidence for this view emerges from genome scanning for quantitative trait loci (QTL), which in the case of the immune system points to a major contribution of pro-inflammatory cytokine genes. Further support comes from sequencing of major histocompatibility complex (Mhc) class II promoters, where a high level of polymorphism has been detected. These Mhc promoters appear to act, in part at least, by gating the back-signal from T cells into antigen-presenting cells. Both these forms of polymorphism are likely to be sustained by the need for flexibility in the immune response. Future work on promoter polymorphism is likely to benefit from the input from genome informatics.

  6. The ultraviolet variations of iota Cas

    Science.gov (United States)

    Molnar, M. R.; Mallama, A. D.; Soskey, D. G.; Holm, A. V.

    1976-01-01

    The Ap variable star iota Cas was observed with the photometers on OAO-2 covering the spectral range 1430-4250 A. The ultraviolet light curves show a double wave with primary minimum and maximum at phase ? 0.00 and 0.35, respectively. Secondary minimum light is at phase ? 0.65 with secondary maximum at phase ? 0.85. The light curves longward of 3150 A vary in opposition to those shortward of this 'null region'. Ground-based coude spectra show that the Fe II and Cr II line strengths have a double-wave variation such that maximum strength occurs at minimum ultraviolet light. We suggest that the strong ultraviolet opacities due to photoionization and line blanketing by these metals may cause the observed photometric variations. We have also constructed an oblique-rotator model which shows iron and chromium lying in a great circle band rather than in circular spots.

  7. Simulation of Cycle-to-Cycle Variation in Dual-Fuel Engines

    KAUST Repository

    Jaasim, Mohammed

    2017-03-13

    Standard practices of internal combustion (IC) engine experiments are to conduct the measurements of quantities averaged over a large number of cycles. Depending on the operating conditions, the cycle-to-cycle variation (CCV) of quantities, such as the indicated mean effective pressure (IMEP) are observed at different levels. Accurate prediction of CCV in IC engines is an important but challenging task. Computational fluid dynamics (CFD) simulations using high performance computing (HPC) can be used effectively to visualize such 3D spatial distributions. In the present study, a dual fuel large engine is considered, with natural gas injected into the manifold accompanied with direct injection of diesel pilot fuel to trigger ignition. Multiple engine cycles in 3D are simulated in series as in the experiments to investigate the potential of HPC based high fidelity simulations to accurately capture the cycle to cycle variation in dual fuel engines. Open cycle simulations are conducted to predict the combined effect of the stratification of fuel-air mixture, temperature and turbulence on the CCV of pressure. The predicted coefficient of variation (COV) of pressure compared to the results from closed cycle simulations and the experiments.

  8. Large-Ensemble modeling of past and future variations of the Antarctic Ice Sheet with a coupled ice-Earth-sea level model

    Science.gov (United States)

    Pollard, David; DeConto, Robert; Gomez, Natalya

    2016-04-01

    To date, most modeling of the Antarctic Ice Sheet's response to future warming has been calibrated using recent and modern observations. As an alternate approach, we apply a hybrid 3-D ice sheet-shelf model to the last deglacial retreat of Antarctica, making use of geologic data of the last ~20,000 years to test the model against the large-scale variations during this period. The ice model is coupled to a global Earth-sea level model to improve modeling of the bedrock response and to capture ocean-ice gravitational interactions. Following several recent ice-sheet studies, we use Large Ensemble (LE) statistical methods, performing sets of 625 runs from 30,000 years to present with systematically varying model parameters. Objective scores for each run are calculated using modern data and past reconstructed grounding lines, relative sea level records, cosmogenic elevation-age data and uplift rates. The LE results are analyzed to calibrate 4 particularly uncertain model parameters that concern marginal ice processes and interaction with the ocean. LE's are extended into the future with climates following RCP scenarios. An additional scoring criterion tests the model's ability to reproduce estimated sea-level high stands in the warm mid-Pliocene, for which drastic retreat mechanisms of hydrofracturing and ice-cliff failure are needed in the model. The LE analysis provides future sea-level-rise envelopes with well-defined parametric uncertainty bounds. Sensitivities of future LE results to Pliocene sea-level estimates, coupling to the Earth-sea level model, and vertical profiles of Earth properties, will be presented.

  9. Dynamics of nonholonomic systems from variational principles embedded variation identity

    Energy Technology Data Exchange (ETDEWEB)

    Guo Yongxin, E-mail: yxguo@lnu.edu.c [College of Physics, Liaoning University, Shenyang 110036 (China); Liu Shixing [College of Physics, Liaoning University, Shenyang 110036 (China); Liu Chang; Chang Peng [Department of Applied Mechanics, Beijing Institute of Technology, Beijing 100081 (China)

    2009-10-19

    Nondeterminacy of dynamics, i.e., the nonholonomic or the vakonomic, fundamental variational principles, e.g., the Lagrange-d'Alembert or Hamiltonian, and variational operators, etc., of nonholonomic mechanical systems can be attributed to the non-uniqueness of ways how to realize nonholonomic constraints. Making use of a variation identity of nonholonomic constraints embedded into the Hamilton's principle with the method of Lagrange undetermined multipliers, three kinds of dynamics for the nonholonomic systems including the vakonomic and nonholonomic ones and a new one are obtained if the variation is respectively reduced to three conditional variations: vakonomic variation, Hoelder's variation and Suslov's variation, defined by the identity. Therefore, different dynamics of nonholonomic systems can be derived from an integral variational principle, utilizing one way of embedding constraints into the principle, with different variations. It is verified that the similar embedding of the identity into the Lagrange-d'Alembert principle gives rise to the nonholonomic dynamics but fails to give the vakonomic one unless the constraints are integrable.

  10. A database and API for variation, dense genotyping and resequencing data

    Directory of Open Access Journals (Sweden)

    Flicek Paul

    2010-05-01

    Full Text Available Abstract Background Advances in sequencing and genotyping technologies are leading to the widespread availability of multi-species variation data, dense genotype data and large-scale resequencing projects. The 1000 Genomes Project and similar efforts in other species are challenging the methods previously used for storage and manipulation of such data necessitating the redesign of existing genome-wide bioinformatics resources. Results Ensembl has created a database and software library to support data storage, analysis and access to the existing and emerging variation data from large mammalian and vertebrate genomes. These tools scale to thousands of individual genome sequences and are integrated into the Ensembl infrastructure for genome annotation and visualisation. The database and software system is easily expanded to integrate both public and non-public data sources in the context of an Ensembl software installation and is already being used outside of the Ensembl project in a number of database and application environments. Conclusions Ensembl's powerful, flexible and open source infrastructure for the management of variation, genotyping and resequencing data is freely available at http://www.ensembl.org.

  11. Canonical variate regression.

    Science.gov (United States)

    Luo, Chongliang; Liu, Jin; Dey, Dipak K; Chen, Kun

    2016-07-01

    In many fields, multi-view datasets, measuring multiple distinct but interrelated sets of characteristics on the same set of subjects, together with data on certain outcomes or phenotypes, are routinely collected. The objective in such a problem is often two-fold: both to explore the association structures of multiple sets of measurements and to develop a parsimonious model for predicting the future outcomes. We study a unified canonical variate regression framework to tackle the two problems simultaneously. The proposed criterion integrates multiple canonical correlation analysis with predictive modeling, balancing between the association strength of the canonical variates and their joint predictive power on the outcomes. Moreover, the proposed criterion seeks multiple sets of canonical variates simultaneously to enable the examination of their joint effects on the outcomes, and is able to handle multivariate and non-Gaussian outcomes. An efficient algorithm based on variable splitting and Lagrangian multipliers is proposed. Simulation studies show the superior performance of the proposed approach. We demonstrate the effectiveness of the proposed approach in an [Formula: see text] intercross mice study and an alcohol dependence study. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Climate variations and the enhanced greenhouse effect

    Energy Technology Data Exchange (ETDEWEB)

    Karlen, W. [Stockholm Univ. (Sweden). Dept. of Physical Geography

    1998-06-01

    Changes in the size of glaciers, in the altitude of the alpine tree-limit, and variation in the width of tree-rings during the Holocene clearly indicate that the average Scandinavian summer temperature has fluctuated. During warm periods it has been about 2 deg C warmer than at present; during cold periods it has been almost as cold as it was during the coldest decades of the previous centuries. Superimposed on these long-term variations, which have lasted from 100 to 200 years, are short fluctuations in temperature. The Scandinavian chronology, which is based on glacier and alpine tree-limit fluctuations as well as on dendrochronology, is well correlated with the changes in climate, which studies of ice cores from central Greenland have revealed. It is therefore believed that the Scandinavian climate chronology depicts conditions typical of a large area. The Scandinavian record is compared with data concerning solar irradiation variations estimated as {sup 14}C anomalies obtained from tree-rings. A correlation between major changes in climate and variations in solar irradiation points to a solar forcing of the climate. This means that there is no evidence of a human influence on climate so far Special issue. Research for mountain area development: Europe. 64 refs, 3 figs

  13. Modeling Geomagnetic Variations using a Machine Learning Framework

    Science.gov (United States)

    Cheung, C. M. M.; Handmer, C.; Kosar, B.; Gerules, G.; Poduval, B.; Mackintosh, G.; Munoz-Jaramillo, A.; Bobra, M.; Hernandez, T.; McGranaghan, R. M.

    2017-12-01

    We present a framework for data-driven modeling of Heliophysics time series data. The Solar Terrestrial Interaction Neural net Generator (STING) is an open source python module built on top of state-of-the-art statistical learning frameworks (traditional machine learning methods as well as deep learning). To showcase the capability of STING, we deploy it for the problem of predicting the temporal variation of geomagnetic fields. The data used includes solar wind measurements from the OMNI database and geomagnetic field data taken by magnetometers at US Geological Survey observatories. We examine the predictive capability of different machine learning techniques (recurrent neural networks, support vector machines) for a range of forecasting times (minutes to 12 hours). STING is designed to be extensible to other types of data. We show how STING can be used on large sets of data from different sensors/observatories and adapted to tackle other problems in Heliophysics.

  14. Variation in Payment Rates under Medicare's Inpatient Prospective Payment System.

    Science.gov (United States)

    Krinsky, Sam; Ryan, Andrew M; Mijanovich, Tod; Blustein, Jan

    2017-04-01

    To measure variation in payment rates under Medicare's Inpatient Prospective Payment System (IPPS) and identify the main payment adjustments that drive variation. Medicare cost reports for all Medicare-certified hospitals, 1987-2013, and Dartmouth Atlas geographic files. We measure the Medicare payment rate as a hospital's total acute inpatient Medicare Part A payment, divided by the standard IPPS payment for its geographic area. We assess variation using several measures, both within local markets and nationally. We perform a factor decomposition to identify the share of variation attributable to specific adjustments. We also describe the characteristics of hospitals receiving different payment rates and evaluate changes in the magnitude of the main adjustments over time. Data downloaded from the Centers for Medicare and Medicaid Services, the National Bureau of Economic Research, and the Dartmouth Atlas. In 2013, Medicare paid for acute inpatient discharges at a rate 31 percent above the IPPS base. For the top 10 percent of discharges, the mean rate was double the IPPS base. Variations were driven by adjustments for medical education and care to low-income populations. The magnitude of variation has increased over time. Adjustments are a large and growing share of Medicare hospital payments, and they create significant variation in payment rates. © Health Research and Educational Trust.

  15. Application of the control variate technique to estimation of total sensitivity indices

    International Nuclear Information System (INIS)

    Kucherenko, S.; Delpuech, B.; Iooss, B.; Tarantola, S.

    2015-01-01

    Global sensitivity analysis is widely used in many areas of science, biology, sociology and policy planning. The variance-based methods also known as Sobol' sensitivity indices has become the method of choice among practitioners due to its efficiency and ease of interpretation. For complex practical problems, estimation of Sobol' sensitivity indices generally requires a large number of function evaluations to achieve reasonable convergence. To improve the efficiency of the Monte Carlo estimates for the Sobol' total sensitivity indices we apply the control variate reduction technique and develop a new formula for evaluation of total sensitivity indices. Presented results using well known test functions show the efficiency of the developed technique. - Highlights: • We analyse the efficiency of the Monte Carlo estimates of Sobol' sensitivity indices. • The control variate technique is applied for estimation of total sensitivity indices. • We develop a new formula for evaluation of Sobol' total sensitivity indices. • We present test results demonstrating the high efficiency of the developed formula

  16. Presymplectic current and the inverse problem of the calculus of variations

    NARCIS (Netherlands)

    Khavkine, I.

    2013-01-01

    The inverse problem of the calculus of variations asks whether a given system of partial differential equations (PDEs) admits a variational formulation. We show that the existence of a presymplectic form in the variational bicomplex, when horizontally closed on solutions, allows us to construct a

  17. Seasonal variations of antioxidants in the brown seaweed Saccharina latissima

    DEFF Research Database (Denmark)

    Sørensen, Ann-Dorit Moltke; Safafar, Hamed; Pedersen, Anja

    Mainly the brown seaweeds are known for their high antioxidative capacity within the specific compounds such as phlorotannins, polyphenols, flavonoids, pigments, and these natural antioxidants are of high industrial interest. Previous studies have shown large seasonal variations in biomass...... composition. The aim of this study was to see if there was a seasonal variation in the antioxidant content of sugar kelp (Saccharina latissima), compare two cultivation sites, REF and IMTA, and test different solvents applied for extractions, methanol or ethyl acetate. Rope cultivated sugar kelp were sampled...

  18. Varying couplings in the early universe: Correlated variations of α and G

    International Nuclear Information System (INIS)

    Martins, C. J. A. P.; Menegoni, Eloisa; Galli, Silvia; Mangano, Gianpiero; Melchiorri, Alessandro

    2010-01-01

    The cosmic microwave background anisotropies provide a unique opportunity to constrain simultaneous variations of the fine-structure constant α and Newton's gravitational constant G. Those correlated variations are possible in a wide class of theoretical models. In this brief paper we show that the current data, assuming that particle masses are constant, give no clear indication for such variations, but already prefer that any relative variations in α should be of the same sign of those of G for variations of ∼1%. We also show that a cosmic complementarity is present with big bang nucleosynthesis and that a combination of current CMB and big bang nucleosynthesis data strongly constraints simultaneous variations in α and G. We finally discuss the future bounds achievable by the Planck satellite mission.

  19. Genetic diversity and variation of mitochondrial DNA in native and introduced bighead carp

    Science.gov (United States)

    Li, Si-Fa; Yang, Qin-Ling; Xu, Jia-Wei; Wang, Cheng-Hui; Chapman, Duane C.; Lu, Guoping

    2010-01-01

    The bighead carp Hypophthalmichthys nobilis is native to China but has been introduced to over 70 countries and is established in many large river systems. Genetic diversity and variation in introduced bighead carp have not previously been evaluated, and a systematic comparison among fish from different river systems was unavailable. In this study, 190 bighead carp specimens were sampled from five river systems in three countries (Yangtze, Pearl, and Amur rivers, China; Danube River, Hungary; Mississippi River basin, USA) and their mitochondrial 16S ribosomal RNA gene and D-loop region were sequenced (around 1,345 base pairs). Moderate genetic diversity was found in bighead carp, ranging from 0.0014 to 0.0043 for nucleotide diversity and from 0.6879 to 0.9333 for haplotype diversity. Haplotype analysis provided evidence that (1) multiple haplotype groups might be present among bighead carp, (2) bighead carp probably originated from the Yangtze River, and (3) bighead carp in the Mississippi River basin may have some genetic ancestry in the Danube River. The analysis of molecular variance showed significant genetic differentiation among these five populations but also revealed limited differentiation between the Yangtze and Amur River bighead carp. This large-scale study of bighead carp genetic diversity and variation provides the first global perspective of bighead carp in the context of biodiversity conservation as well as invasive species control and management.

  20. Fast solution of Cahn–Hilliard variational inequalities using implicit time discretization and finite elements

    KAUST Repository

    Bosch, Jessica

    2014-04-01

    We consider the efficient solution of the Cahn-Hilliard variational inequality using an implicit time discretization, which is formulated as an optimal control problem with pointwise constraints on the control. By applying a semi-smooth Newton method combined with a Moreau-Yosida regularization technique for handling the control constraints we show superlinear convergence in function space. At the heart of this method lies the solution of large and sparse linear systems for which we propose the use of preconditioned Krylov subspace solvers using an effective Schur complement approximation. Numerical results illustrate the competitiveness of this approach. © 2014 Elsevier Inc.

  1. Sequence Variation of MHC Class II DQB Gene in Bottlenose Dolphin (Tursiops truncatus from Taiwanese Waters

    Directory of Open Access Journals (Sweden)

    Wei-Cheng Yang

    2008-03-01

    Full Text Available The major histocompatibility complex (MHC is a large multigene coding for glycoproteins that play a key role in the initiation of immune responses in vertebrates. For a better understanding of the immunologic diversity in thriving marine mammal species, the sequence variation of the exon 2 region of MHC DQB locus was analyzed in 42 bottlenose dolphins (Tursiops truncatus collected from strandings and fishery bycatch in Taiwanese waters. The 172 bp sequences amplified showed no more than two alleles in each individual. The high proportion of non-synonymous nucleotide substitutions and the moderate amount of variation suggest positive selection pressure on this locus, arguing against a reduction in the marine environment selection pressure. The phylogenetic relationship among DQB exon 2 sequences of T. truncatus and other cetaceans did not coincide with taxonomic relationship, indicating a trans-species evolutionary pattern.

  2. Meta-Analysis of Mitochondrial DNA Variation in the Iberian Peninsula.

    Directory of Open Access Journals (Sweden)

    Ruth Barral-Arca

    Full Text Available The Iberian Peninsula has been the focus of attention of numerous studies dealing with mitochondrial DNA (mtDNA variation, most of them targeting the control region segment. In the present study we sequenced the control region of 3,024 Spanish individuals from areas where available data were still limited. We also compiled mtDNA haplotypes from the literature involving 4,588 sequences and 28 population groups or small regions. We meta-analyzed all these data in order to shed further light on patterns of geographic variation, taking advantage of the large sample size and geographic coverage, in contrast with the atomized sampling strategy of previous work. The results indicate that the main mtDNA haplogroups show primarily clinal geographic patterns across the Iberian geography, roughly along a North-South axis. Haplogroup HV0 (where haplogroup U is nested is more prevalent in the Franco Cantabrian region, in good agreement with previous findings that identified this area as a climate refuge during the Last Glacial Maximum (LGM, prior to a subsequent demographic re-expansion towards Central Europe and the Mediterranean. Typical sub-Saharan and North African lineages are slightly more prevalent in South Iberia, although at low frequencies; this pattern has been shaped mainly by the transatlantic slave trade and the Arab invasion of the Iberian Peninsula. The results also indicate that summary statistics that aim to measure molecular variation, or AMOVA, have limited sensitivity to detect population substructure, in contrast to patterns revealed by phylogeographic analysis. Overall, the results suggest that mtDNA variation in Iberia is substantially stratified. These patterns might be relevant in biomedical studies given that stratification is a common cause of false positives in case-control mtDNA association studies, and should be also considered when weighting the DNA evidence in forensic casework, which is strongly dependent on haplotype

  3. Meta-Analysis of Mitochondrial DNA Variation in the Iberian Peninsula.

    Science.gov (United States)

    Barral-Arca, Ruth; Pischedda, Sara; Gómez-Carballa, Alberto; Pastoriza, Ana; Mosquera-Miguel, Ana; López-Soto, Manuel; Martinón-Torres, Federico; Álvarez-Iglesias, Vanesa; Salas, Antonio

    2016-01-01

    The Iberian Peninsula has been the focus of attention of numerous studies dealing with mitochondrial DNA (mtDNA) variation, most of them targeting the control region segment. In the present study we sequenced the control region of 3,024 Spanish individuals from areas where available data were still limited. We also compiled mtDNA haplotypes from the literature involving 4,588 sequences and 28 population groups or small regions. We meta-analyzed all these data in order to shed further light on patterns of geographic variation, taking advantage of the large sample size and geographic coverage, in contrast with the atomized sampling strategy of previous work. The results indicate that the main mtDNA haplogroups show primarily clinal geographic patterns across the Iberian geography, roughly along a North-South axis. Haplogroup HV0 (where haplogroup U is nested) is more prevalent in the Franco Cantabrian region, in good agreement with previous findings that identified this area as a climate refuge during the Last Glacial Maximum (LGM), prior to a subsequent demographic re-expansion towards Central Europe and the Mediterranean. Typical sub-Saharan and North African lineages are slightly more prevalent in South Iberia, although at low frequencies; this pattern has been shaped mainly by the transatlantic slave trade and the Arab invasion of the Iberian Peninsula. The results also indicate that summary statistics that aim to measure molecular variation, or AMOVA, have limited sensitivity to detect population substructure, in contrast to patterns revealed by phylogeographic analysis. Overall, the results suggest that mtDNA variation in Iberia is substantially stratified. These patterns might be relevant in biomedical studies given that stratification is a common cause of false positives in case-control mtDNA association studies, and should be also considered when weighting the DNA evidence in forensic casework, which is strongly dependent on haplotype frequencies.

  4. Assemblages of saproxylic beetles on large downed trunks of oak.

    Science.gov (United States)

    Milberg, Per; Bergman, Karl-Olof; Sancak, Kerem; Jansson, Nicklas

    2016-03-01

    Old living oaks (Quercus robur) are known as a very species-rich habitat for saproxylic beetles, but it is less clear to what extent such veteran trees differ from an even rarer feature: downed trunks of large oaks. In this study, we set out to sample this habitat, using window traps, with two aims: (1) to describe the variation of assemblages among downed trunks of different type and (2) to compare beetles on downed oaks with data from veteran standing trees. The results showed that trunk volume and sun exposure better explained assemblages as well as species numbers on downed trunks than did decay stage. Furthermore, species classified as facultative saproxylic species showed weak or no differentiation among downed trunks. Species with different feeding habits showed no apparent differentiation among downed trunks. Furthermore, species composition on dead, downed oak trunks differed sharply from that of living, veteran oaks. Wood or bark feeders were more common on veterans than downed trunks, but there was no difference for those species feeding on fungi or those feeding on insects and their remains. In conclusion, for a successful conservation of the saproxylic beetle fauna it is important to keep downed oak trunks, and particularly large ones, in forest and pastures as they constitute a saproxylic habitat that differs from that of living trees.

  5. Spatio-temporal Variations of Nitrogen Dioxide over Western China from Satellite Observations during 2005-2013

    Science.gov (United States)

    Cui, Y.; Lin, J.; Huang, B.; Song, C.

    2015-12-01

    Western China has experienced rapid urbanization and industrialization since the implementation of National Western Development Strategy by Chinese Government. Most resource-intensive industries and high-pollution factories had been moved from the east coast to Western China after 2000. In this research, the spatial and temporal variations of tropospheric NO2 concentration in 2005 - 2013 is analyzed based on the satellite observations by Ozone Measurement Instrument (OMI). The annual trends and seasonality of tropospheric NO2 over Western China are calculated. The results show that large increases are observed in urban areas and the polluted regions are expanding. Additionally, the seasonal patterns of some regions over Western China are changing significantly and more clean areas tend to changing from the characteristics of natural emissions to those of anthropogenic emissions. The spatial and temporal variations of NO2 concentrations are well responded to the rapid urbanization and industrialization over Western China.

  6. Color Variation on the Surfaces of Jupiter’s Greek and Trojan Asteroids

    Science.gov (United States)

    Chatelain, Joseph; Trilling, David E.; Emery, Joshua P.

    2017-10-01

    The L4 and L5 Lagrange points of Jupiter are populated with thousands of known, and possibly hundreds of thousands of unknown, Greek and Trojan Asteroids. Understanding the environmental and weathering conditions experienced by these objects over their lifetimes could constrain formation models for the Solar System. In an effort to shine some light on this issue, we have collected partial, simultaneous, lightcurves in both Johnson-Cousins V and I filters for a dozen large Jupiter Trojans. We found significant signs of color variation over the surfaces of four of these objects, and more subtle signs on an additional four. The most convincing examples of variation occur on (4709) Ennomos and (4833) Meges. Such a variation in color with rotation likely implies a large surface feature such as a recent crater. That such a high fraction of observed Trojans display these signatures could imply a more active collisional history for Jupiter Trojans than previously thought. It is therefore likely that one or more of the targets for the Lucy mission will have experienced a large, relatively recent, cratering event. This may help us obtain a much more in-depth understanding of the evolutionary processes ongoing for the Jupiter Trojan populations.

  7. EqualChance: Addressing Intra-set Write Variation to Increase Lifetime of Non-volatile Caches

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Sparsh [ORNL; Vetter, Jeffrey S [ORNL

    2014-01-01

    To address the limitations of SRAM such as high-leakage and low-density, researchers have explored use of non-volatile memory (NVM) devices, such as ReRAM (resistive RAM) and STT-RAM (spin transfer torque RAM) for designing on-chip caches. A crucial limitation of NVMs, however, is that their write endurance is low and the large intra-set write variation introduced by existing cache management policies may further exacerbate this problem, thereby reducing the cache lifetime significantly. We present EqualChance, a technique to increase cache lifetime by reducing intra-set write variation. EqualChance works by periodically changing the physical cache-block location of a write-intensive data item within a set to achieve wear-leveling. Simulations using workloads from SPEC CPU2006 suite and HPC (high-performance computing) field show that EqualChance improves the cache lifetime by 4.29X. Also, its implementation overhead is small, and it incurs very small performance and energy loss.

  8. A digital gigapixel large-format tile-scan camera.

    Science.gov (United States)

    Ben-Ezra, M

    2011-01-01

    Although the resolution of single-lens reflex (SLR) and medium-format digital cameras has increased in recent years, applications for cultural-heritage preservation and computational photography require even higher resolutions. Addressing this issue, a large-format cameras' large image planes can achieve very high resolution without compromising pixel size and thus can provide high-quality, high-resolution images.This digital large-format tile scan camera can acquire high-quality, high-resolution images of static scenes. It employs unique calibration techniques and a simple algorithm for focal-stack processing of very large images with significant magnification variations. The camera automatically collects overlapping focal stacks and processes them into a high-resolution, extended-depth-of-field image.

  9. Estimating variation in stomatal frequency at intra-individual, intra-site, and inter-taxonomic levels in populations of the Leonardoxa africana (Fabaceae) complex over environmental gradients in Cameroon

    Science.gov (United States)

    Finsinger, Walter; Dos Santos, Thibaut; McKey, Doyle

    2013-07-01

    Variation of stomatal frequency (stomatal density and stomatal index) includes genetically-based, potentially-adaptive variation, and variation due to phenotypic plasticity, the degree of which may be fundamental to the ability to maintain high water-use efficiency and thus to deal with environmental change. We analysed stomatal frequency and morphology (pore length, pore width) in leaves from several individuals from nine populations of four sub-species of the Leonardoxa africana complex. The dataset represents a hierarchical sampling wherein factors are nested within each level (leaves in individuals, individuals in sites, etc.), allowing estimation of the contribution of different levels to overall variation, using variance-component analysis. SI showed significant variation among sites ("site" is largely confounded with "sub-species"), being highest in the sub-species localized in the highest-elevation site. However, most of the observed variance was accounted for at intra-site and intra-individual levels. This variance could reflect great phenotypic plasticity, presumably in response to highly local variation in micro-environmental conditions.

  10. Transcriptome analysis reveals novel patterning and pigmentation genes underlying Heliconius butterfly wing pattern variation

    Directory of Open Access Journals (Sweden)

    Hines Heather M

    2012-06-01

    Full Text Available Abstract Background Heliconius butterfly wing pattern diversity offers a unique opportunity to investigate how natural genetic variation can drive the evolution of complex adaptive phenotypes. Positional cloning and candidate gene studies have identified a handful of regulatory and pigmentation genes implicated in Heliconius wing pattern variation, but little is known about the greater developmental networks within which these genes interact to pattern a wing. Here we took a large-scale transcriptomic approach to identify the network of genes involved in Heliconius wing pattern development and variation. This included applying over 140 transcriptome microarrays to assay gene expression in dissected wing pattern elements across a range of developmental stages and wing pattern morphs of Heliconius erato. Results We identified a number of putative early prepattern genes with color-pattern related expression domains. We also identified 51 genes differentially expressed in association with natural color pattern variation. Of these, the previously identified color pattern “switch gene” optix was recovered as the first transcript to show color-specific differential expression. Most differentially expressed genes were transcribed late in pupal development and have roles in cuticle formation or pigment synthesis. These include previously undescribed transporter genes associated with ommochrome pigmentation. Furthermore, we observed upregulation of melanin-repressing genes such as ebony and Dat1 in non-melanic patterns. Conclusions This study identifies many new genes implicated in butterfly wing pattern development and provides a glimpse into the number and types of genes affected by variation in genes that drive color pattern evolution.

  11. Calculus of variations

    CERN Document Server

    Elsgolc, L E; Stark, M

    1961-01-01

    Calculus of Variations aims to provide an understanding of the basic notions and standard methods of the calculus of variations, including the direct methods of solution of the variational problems. The wide variety of applications of variational methods to different fields of mechanics and technology has made it essential for engineers to learn the fundamentals of the calculus of variations. The book begins with a discussion of the method of variation in problems with fixed boundaries. Subsequent chapters cover variational problems with movable boundaries and some other problems; sufficiency

  12. Exploring natural variation of photosynthetic, primary metabolism and growth parameters in a large panel of Capsicum chinense accessions.

    Science.gov (United States)

    Rosado-Souza, Laise; Scossa, Federico; Chaves, Izabel S; Kleessen, Sabrina; Salvador, Luiz F D; Milagre, Jocimar C; Finger, Fernando; Bhering, Leonardo L; Sulpice, Ronan; Araújo, Wagner L; Nikoloski, Zoran; Fernie, Alisdair R; Nunes-Nesi, Adriano

    2015-09-01

    Collectively, the results presented improve upon the utility of an important genetic resource and attest to a complex genetic basis for differences in both leaf metabolism and fruit morphology between natural populations. Diversity of accessions within the same species provides an alternative method to identify physiological and metabolic traits that have large effects on growth regulation, biomass and fruit production. Here, we investigated physiological and metabolic traits as well as parameters related to plant growth and fruit production of 49 phenotypically diverse pepper accessions of Capsicum chinense grown ex situ under controlled conditions. Although single-trait analysis identified up to seven distinct groups of accessions, working with the whole data set by multivariate analyses allowed the separation of the 49 accessions in three clusters. Using all 23 measured parameters and data from the geographic origin for these accessions, positive correlations between the combined phenotypes and geographic origin were observed, supporting a robust pattern of isolation-by-distance. In addition, we found that fruit set was positively correlated with photosynthesis-related parameters, which, however, do not explain alone the differences in accession susceptibility to fruit abortion. Our results demonstrated that, although the accessions belong to the same species, they exhibit considerable natural intraspecific variation with respect to physiological and metabolic parameters, presenting diverse adaptation mechanisms and being a highly interesting source of information for plant breeders. This study also represents the first study combining photosynthetic, primary metabolism and growth parameters for Capsicum to date.

  13. Study on the wide-angle Michelson interferometer with large air gap.

    Science.gov (United States)

    Gao, Haiyang; Tang, Yuanhe; Hua, Dengxin; Liu, Hanchen

    2011-10-10

    A wide-angle Michelson interferometer with large air gap is proposed to effectively reduce the size of the glass arms and constraint on material. It provides a novel and practical instrument for ground based wind measurement of the upper atmosphere. The field widening conditions for the large air gap are calculated in theory. For the five spectral lines of 557.7 nm, 630.0 nm, 732.0 nm, 834.6 nm, and 865.7 nm, the optimal results under ideal condition are obtained with air gaps of 1.0 cm, 1.5 cm, and 2.0 cm, respectively. With the fixed optical path difference (OPD) of 7.495 cm, three pairs of glass arms are optimized. The pair with length of 1.5 cm for air gap, 5.765 cm for H-ZF12, and 2.956 cm for H-ZLaF54, has better effect of field widening than the other two pairs and its OPD variation is only within 0.30 wavelengths at incident angle of 3°. For developing a more practical wide-angle Michelson interferometer, the H-K9L glass with size of 4.445 cm is employed as the arm material of solid interferometer. The experiment for field of view of 3° is designed and the data processing and analysis for 60 images show the agreement between experimental results and theoretical simulation. The OPD variations are only within 0.27 wavelengths for image edge. The feasibility and practicality of the wide-angle Michelson interferometer with large air gap is proved by means of theory and experiment. © 2011 Optical Society of America

  14. LARGE VESSEL INVOLVEMENT IN BEHCET’S DISEASE

    Directory of Open Access Journals (Sweden)

    AR. Jamshidi F. Davatchi

    2004-08-01

    Full Text Available Large vessel involvement is one of the hallmarks of Behcet’s disease (BD but its prevalence varies widely due to ethnic variation or environmental factors. The aim of this study is to find the characteristics of vasculo-Behcet (VB in Iran. In a cohort of 4769 patients with BD, those with vascular involvement were selected. Different manifestations of disease were compared with the remaining group of patients. A confidence interval at 95% (CI was calculated for