Hospital Variation in Intensive Care Resource Utilization and Mortality in Newly Diagnosed Pediatric Leukemia.

PubMed

Fitzgerald, Julie C; Li, Yimei; Fisher, Brian T; Huang, Yuan-Shung; Miller, Tamara P; Bagatell, Rochelle; Seif, Alix E; Aplenc, Richard; Thomas, Neal J

2018-06-01

To evaluate hospital-level variability in resource utilization and mortality in children with new leukemia who require ICU support, and identify factors associated with variation. Retrospective cohort study. Children's hospitals contributing to the Pediatric Health Information Systems administrative database from 1999 to 2011. Inpatients less than 25 years old with newly diagnosed acute lymphocytic leukemia or acute myeloid leukemia requiring ICU support (n = 1,754). Evaluated exposures included leukemia type, year of diagnosis, and hospital-wide proportion of patients with public insurance. The main outcome was hospital mortality. Wide variability existed in the ICU resources used across hospitals. Combined acute lymphocytic leukemia and acute myeloid leukemia mortality varied by hospital from 0% (95% CI, 0-14.8%) to 42.9% (95% CI, 17.7-71.1%). A mixed-effects model with a hospital-level random effect suggests significant variation across hospitals in mortality (p = 0.007). When including patient and hospital factors as fixed effects into the model, younger age, acute myeloid leukemia versus acute lymphocytic leukemia diagnosis, leukemia diagnosis prior to 2005, hospital-wide proportion of public insurance patients, and hospital-level proportion of leukemia patients receiving ICU care are significantly associated with mortality. The variation across hospitals remains significant with all patient factors included (p = 0.021) but is no longer significant after adjusting for the hospital-level factors proportion of public insurance and proportion receiving ICU care (p = 0.48). Wide hospital-level variability in ICU resource utilization and mortality exists in the care of children with leukemia requiring ICU support. Hospital payer mix is associated with some mortality variability. Additional study into how ICU support could be standardized through clinical practice guidelines, impact of payer mix on hospital resources allocation to the ICU, and subsequent impact on patient outcomes is warranted.

Heritability of circulating growth factors involved in the angiogenesis in healthy human population.

PubMed

Pantsulaia, I; Trofimov, S; Kobyliansky, E; Livshits, G

2004-09-21

The present study examined the extent of genetic and environmental influences on the populational variation of circulating growth factors (VEGF, EGF) involved in angiogenesis in healthy and ethnically homogeneous Caucasian families. The plasma levels of each of the studied biochemical indices were determined by enzyme-linked immunoassay in 478 healthy individuals aged 18-75 years. Quantitative genetic analysis showed that the VEGF and EGF variation was appreciably attributable to genetic effects, with heritability estimates of 79.9% and 48.4%, respectively. Yet, common environmental factors, shared by members of the same household, also played a significant role (P < 0.01) and explained between 20.1% and 32.6% of the variation. The present study additionally examined the covariations between these molecules and either transforming growth factor-beta 1 (TGF-beta 1) or tissue inhibitors of matrix metalloproteinases 1 (TIMP-1), likewise relevant for angiogenesis. Bivariate analysis revealed significant phenotypic correlations (P < 0.002) between all pairs of variables, thus indicating the possible existence of common genetic and environmental factors. The analysis suggested that the pleiotropic genetic effects were consistently the primary (or even the sole) source of correlation between all pairs of studied molecules. The results of our study affirm the existence of specific and common genetic pathways that commonly determine the greater part of the circulating variation of these molecules.

Hydrological and oceanic excitations to polar motion andlength-of-day variation

NASA Astrophysics Data System (ADS)

Chen, J. L.; Wilson, C. R.; Chao, B. F.; Shum, C. K.; Tapley, B. D.

2000-04-01

Water mass redistributions in the global hydrosphere, including continental water storage change and non-steric sea level change, introduce variations in the hydrological angular momentum (HAM) and the oceanic angular momentum (OAM). Under the conservation of angular momentum, HAM and OAM variations are significant excitation sources of the Earth rotational variations at a wide range of timescales. In this paper, we estimate HAM and OAM variations and their excitations to polar motion and length-of-day variation using soil moisture and snow estimates andnon-steric sea level change determined by TOPEX/Poseidon satellite radar altimeter observations and a simplified steric sea level change model. The results are compared with the variations of polar motion and LOD that are not accounted for by the atmosphere. This study indicates that seasonal continental water storage change provides significant contributions to both polar motion and LOD variation, especially to polar motion X, and the non-steric sea level change is responsible for a major part of the remaining excitations at both seasonal scale and high frequencies, particularly in polar motion Y and LOD. The good correlation between OAM contributions and the remaining excitations shows that large-scale non-tidal mass variation exists in the oceans and can be detected by TOPEX/Poseidon altimeter observations.

Morphological Variation and Inter-Relationships of Quantitative Traits in Enset (Ensete ventricosum (welw.) Cheesman) Germplasm from South and South-Western Ethiopia

PubMed Central

Yemataw, Zerihun; Chala, Alemayehu; Grant, Murray R.

2017-01-01

Enset (Ensete ventricosum (Welw.) Cheesman) is Ethiopia’s most important root crop. A total of 387 accessions collected from nine different regions of Ethiopia were evaluated for 15 quantitative traits at Areka Agricultural Research Centre to determine the extent and pattern of distribution of morphological variation. The variations among the accessions and regions were significant (p ≤ 0.01) for all the 15 traits studied. Mean for plant height, central shoot weight before grating, and fermented squeezed kocho yield per hectare per year showed regional variation along an altitude gradient and across cultural differences related to the origin of the collection. Furthermore, there were significant correlations among most of the characters. This included the correlation among agronomic characteristics of primary interest in enset breeding such as plant height, pseudostem height, and fermented squeezed kocho yield per hectare per year. Altitude of the collection sites also significantly impacted the various characteristics studied. These results reveal the existence of significant phenotypic variations among the 387 accessions as a whole. Regional differentiations were also evident among the accessions. The implication of the current results for plant breeding, germplasm collection, and in situ and ex situ genetic resource conservation are discussed. PMID:29210979

Interpretable functional principal component analysis.

PubMed

Lin, Zhenhua; Wang, Liangliang; Cao, Jiguo

2016-09-01

Functional principal component analysis (FPCA) is a popular approach to explore major sources of variation in a sample of random curves. These major sources of variation are represented by functional principal components (FPCs). The intervals where the values of FPCs are significant are interpreted as where sample curves have major variations. However, these intervals are often hard for naïve users to identify, because of the vague definition of "significant values". In this article, we develop a novel penalty-based method to derive FPCs that are only nonzero precisely in the intervals where the values of FPCs are significant, whence the derived FPCs possess better interpretability than the FPCs derived from existing methods. To compute the proposed FPCs, we devise an efficient algorithm based on projection deflation techniques. We show that the proposed interpretable FPCs are strongly consistent and asymptotically normal under mild conditions. Simulation studies confirm that with a competitive performance in explaining variations of sample curves, the proposed FPCs are more interpretable than the traditional counterparts. This advantage is demonstrated by analyzing two real datasets, namely, electroencephalography data and Canadian weather data. © 2015, The International Biometric Society.

Blood Mercury Levels of Zebra Finches Are Heritable: Implications for the Evolution of Mercury Resistance

PubMed Central

Buck, Kenton A.; Varian-Ramos, Claire W.; Cristol, Daniel A.; Swaddle, John P.

2016-01-01

Mercury is a ubiquitous metal contaminant that negatively impacts reproduction of wildlife and has many other sub-lethal effects. Songbirds are sensitive bioindicators of mercury toxicity and may suffer population declines as a result of mercury pollution. Current predictions of mercury accumulation and biomagnification often overlook possible genetic variation in mercury uptake and elimination within species and the potential for evolution in affected populations. We conducted a study of dietary mercury exposure in a model songbird species, maintaining a breeding population of zebra finches (Taeniopygia guttata) on standardized diets ranging from 0.0–2.4 μg/g methylmercury. We applied a quantitative genetics approach to examine patterns of variation and heritability of mercury accumulation within dietary treatments using a method of mixed effects modeling known as the 'animal model'. Significant variation in blood mercury accumulation existed within each treatment for birds exposed at the same dietary level; moreover, this variation was highly repeatable for individuals. We observed substantial genetic variation in blood mercury accumulation for birds exposed at intermediate dietary concentrations. Taken together, this is evidence that genetic variation for factors affecting blood mercury accumulation could be acted on by selection. If similar heritability for mercury accumulation exists in wild populations, selection could result in genetic differentiation for populations in contaminated locations, with possible consequences for mercury biomagnification in food webs. PMID:27668745

A Note on the Spatio Temporal Variations in the Temperature and Relative Humidity over Akure, Ondo State, Nigeria

NASA Astrophysics Data System (ADS)

Eludoyin, A. O.; Akinbode, O. M.; Archibong, E. O.

2007-07-01

This study was carried out in one of the Administrative State Capitals in the southwestern part of Nigeria. Its aim is to serve as a baseline data for highlighting the effect of spatial distribution of settlements, population, and socioeconomic activities on urban air temperature and relative humidity. The main objective of the study is to assess the impact of urban growth on the microclimate of the administrative city. Temperature and relative humidity data from 1992 to 2001 were obtained from the three existing meteorological stations in Akure, the Administrative Capital of Ondo State, Nigeria, namely the Federal Ministry of Aviation, Akure Airport station (FMA), Federal University of Technology, Akure (FUTA) and the Federal School of Agriculture (SOA). Air temperature and relative humidity measurements along primary roads and in the built up areas were obtained from seventeen stations, using sling psychrometer. The data were subsequently analysed for spatial and temporal variations. The results obtained indicated that while the maximum, average and minimum temperatures showed significant annual variations, the spatial variations among the existing meteorological stations were not significant. The city is characterized by increasing annual mean temperatures whose maximum was significantly higher than that of Ondo town — another important town within the state. The annual mean temperatures ranged between 26.2°C and 30.4°C. Minimum and maximum temperatures varied from 12.3°C to 26°C and 22.5°C to 39.6°C, respectively while the relative humidity ranged between 27.5% and 98.2%. Urban `heat island' intensity was exhibited around central business district of the Oba market. 2007 American Institute of Physics

Water-flow variation and pharmacoepidemiology of tetracycline hydrochloride administration via drinking water in swine finishing farms.

PubMed

Dorr, Paul M; Nemechek, Megan S; Scheidt, Alan B; Baynes, Ronald E; Gebreyes, Wondwossen A; Almond, Glen W

2009-08-01

To evaluate variation of drinking-water flow rates in swine finishing barns and the relationship between drinker flow rate and plasma tetracycline concentrations in pigs housed in different pens. Cross-sectional (phase 1) and cohort (phase 2) studies. 13 swine finishing farms (100 barns with 7,122 drinkers) in phase 1 and 100 finishing-stage pigs on 2 finishing farms (1 barn/farm) in phase 2. In phase 1, farms were evaluated for water-flow variation, taking into account the following variables: position of drinkers within the barn, type of drinker (swing or mounted), pig medication status, existence of designated sick pen, and existence of leakage from the waterline. In phase 2, blood samples were collected from 50 pigs/barn (40 healthy and 10 sick pigs) in 2 farms at 0, 4, 8, 24, 48, and 72 hours after initiation of water-administered tetracycline HCl (estimated dosage, 22 mg/kg [10 mg/lb]). Plasma tetracycline concentrations were measured via ultraperformance liquid chromatography. Mean farm drinker flow rates ranged from 1.44 to 2.77 L/min. Significant differences in flow rates existed according to drinker type and whether tetracycline was included in the water. Mean drinker flow rates and plasma tetracycline concentrations were significantly different between the 2 farms but were not different between healthy and sick pigs. The plasma tetracycline concentrations were typically < 0.3 microg/mL. Many factors affected drinker flow rates and therefore the amount of medication pigs might have received. Medication of pigs with tetracycline through water as performed in this study had questionable therapeutic value.

Systematic Regional Variations in Purkinje Cell Spiking Patterns

PubMed Central

Xiao, Jianqiang; Cerminara, Nadia L.; Kotsurovskyy, Yuriy; Aoki, Hanako; Burroughs, Amelia; Wise, Andrew K.; Luo, Yuanjun; Marshall, Sarah P.; Sugihara, Izumi; Apps, Richard; Lang, Eric J.

2014-01-01

In contrast to the uniform anatomy of the cerebellar cortex, molecular and physiological studies indicate that significant differences exist between cortical regions, suggesting that the spiking activity of Purkinje cells (PCs) in different regions could also show distinct characteristics. To investigate this possibility we obtained extracellular recordings from PCs in different zebrin bands in crus IIa and vermis lobules VIII and IX in anesthetized rats in order to compare PC firing characteristics between zebrin positive (Z+) and negative (Z−) bands. In addition, we analyzed recordings from PCs in the A2 and C1 zones of several lobules in the posterior lobe, which largely contain Z+ and Z− PCs, respectively. In both datasets significant differences in simple spike (SS) activity were observed between cortical regions. Specifically, Z− and C1 PCs had higher SS firing rates than Z+ and A2 PCs, respectively. The irregularity of SS firing (as assessed by measures of interspike interval distribution) was greater in Z+ bands in both absolute and relative terms. The results regarding systematic variations in complex spike (CS) activity were less consistent, suggesting that while real differences can exist, they may be sensitive to other factors than the cortical location of the PC. However, differences in the interactions between SSs and CSs, including the post-CS pause in SSs and post-pause modulation of SSs, were also consistently observed between bands. Similar, though less strong trends were observed in the zonal recordings. These systematic variations in spontaneous firing characteristics of PCs between zebrin bands in vivo, raises the possibility that fundamental differences in information encoding exist between cerebellar cortical regions. PMID:25144311

Quantitative trait loci controlling amounts and types of epicuticular waxes in onion

USDA-ARS?s Scientific Manuscript database

Natural variation exists in onion (Allium cepa L.) for amounts and types of epicuticular waxes on leaves. Wild-type waxy onion possesses copious amounts of these waxes, while the foliage of semi-glossy and glossy phenotypes accumulate significantly less wax. Reduced amounts of epicuticular waxes hav...

The collagen structure of equine articular cartilage, characterized using polarization-sensitive optical coherence tomography

NASA Astrophysics Data System (ADS)

Ugryumova, Nadya; Attenburrow, Don P.; Winlove, C. Peter; Matcher, Stephen J.

2005-08-01

Optical coherence tomography and polarization-sensitive optical coherence tomography images of equine articular cartilage are presented. Measurements were made on intact joint surfaces. Significant (e.g. × 2) variations in the intrinsic birefringence were found over spatial scales of a few millimetres, even on samples taken from young (18 month) animals that appeared visually homogeneous. A comparison of data obtained on a control tissue (equine flexor tendon) further suggests that significant variations in the orientation of the collagen fibres relative to the plane of the joint surface exist. Images of visually damaged cartilage tissue show characteristic features both in terms of the distribution of optical scatterers and of the birefringent components.

[Characteristics and management of ST-elevation myocardial infarction in France: Regional variations in 2010].

PubMed

Sokoloff, A; Lefèvre, G; Teixeira, N; Puymirat, E; Beygui, F; Vanzetto, G; Richard, P; Khalife, K; Blanchard, D; Gilard, M; Coste, P; Farah, B; Elbaz, M; Leclercq, F; Ferrari, E; Bonnet, J-L; Meyer, P; Belle, L; Funck, F; Motreff, P; Virot, P; Geugniaud, P-Y; Ferrières, J; Simon, T; Danchin, N

2015-12-01

Data on regional variations in the characteristics, management and early outcome of patients admitted with ST-elevation myocardial infarction (STEMI) in France are limited. We used data from the FAST-MI 2010 registry to determine whether regional specificities existed, dividing the French territory into 6 larger geographical regions. Variations in the patients' characteristics were found, partly related to regional variations in demography. Acute reperfusion strategy showed more use of primary percutaneous coronary intervention in the greater Paris area, compared to other regions, which would be expected owing to geography and local availability of catheterization laboratories. Overall, however, in-hospital management showed more similarities than differences across regions. Complications, and in particular in-hospital mortality, did not differ significantly among regions. Copyright © 2015. Published by Elsevier SAS.

Age variations in anthropometric and body composition characteristics and undernutrition among female Bathudis: a tribal population of Keonjhar District, Orissa, India.

PubMed

Bose, Kaushik; Chakraborty, Falguni; Bisai, Samiran

2007-09-01

A cross-sectional study of 183 female Bathudis, a tribal population of the Keonjhar District, Orissa, India, was undertaken to investigate age variations in anthropometric and body composition characteristics and nutritional status. The subjects were categorized into three age groups: < or =30 years, 31-50 years, >50 years. Height, weight, circumferences and skinfolds data were collected. Body mass index (BMI) and several body composition variables and indices were derived using standard equations. The results revealed that there existed significant negative age variations for most of the anthropometric and body composition variables and indices. Correlation studies of age with these variables and indices revealed significant negative correlations. Linear regression analyses revealed that for all variables, age had a significant negative impact. Studies on the nutritional status of these women revealed that with increasing age, there was an increase in the frequency of undernutrition. In conclusion, this study demonstrated that among Bathudi women, age was significantly negatively related with anthropometric and body composition variables and indices. Moreover, with increasing age, the level of undernutrition increased.

Post-treatment management options for patients with lung cancer.

PubMed Central

Virgo, K S; McKirgan, L W; Caputo, M C; Mahurin, D M; Chao, L C; Caputo, N A; Naunheim, K S; Flye, M W; Gillespie, K N; Johnson, F E

1995-01-01

OBJECTIVES: The first objective was to identify variations in patient management practice patterns after potentially curative lung cancer surgery. Patient management practice patterns were expected to range from intensive follow-up to no active surveillance. The second objective was to measure whether intensity of follow-up was related to patient outcomes. METHODS: An 18-month retrospective analysis was conducted of 182 patients with low TNM stage (< or = IIIA) lung cancer who were surgically treated with curative intent over the 11-year period from 1982 through 1992 at the St. Louis Department of Veterans Affairs Medical Center. RESULTS: Patients were followed for a mean of 3.3 years, until death or the end of the study. Analyses of diagnostic test and outpatient visit frequency distributions and cluster analyses facilitated the identification of 62 nonintensively followed patients and 120 intensively followed patients. Both groups were comparable at baseline, and there were no significant differences in patient outcomes attributable to intensity of follow-up. Intensively followed patients did, however, live an average of 192 days longer than nonintensively followed patients. CONCLUSIONS: Significant variations in follow-up practice patterns can exist within a single health care facility. In this analysis, variations in test and visit frequency did not result in statistically significant differences in patient outcomes, though the survival difference between groups suggests that some benefit might exist. Only well-designed prospective trials are likely to answer the question of what constitutes optimal follow-up after potentially curative lung cancer treatment. PMID:8526576

Isostatic models and isostatic gravity anomalies of the Arabian plate and surroundings

NASA Astrophysics Data System (ADS)

Kaban, Mikhail K.; El Khrepy, Sami; Al-Arifi, Nassir

2015-04-01

Isostaic anomalies represent one of the most useful "geological" reduction of the gravity field. With the isostatic correction it is possible to remove a significant part of the effect of deep density heterogeneity, which dominates in the Bouguer gravity anomalies. This correction is based on the fact that a major part of the near-surface load is compensated by variations of the lithosphere boundaries (chiefly the Moho and LAB) and by density variations within the crust and upper mantle. It is usually supposed that it is less important to a first order, what is the actual compensation model when reducing the effect of compensating masses, since their total weight is exactly opposite to the near-surface load. We compare several compensating models for the Arabian plate and surrounding area. The Airy model gives very significant regional isostatic anomalies, which can not be explained by the upper crust structure or disturbances of the isostatic equilibrium. Also the predicted "isostatic" Moho is very different from the existing observations. The second group of the isostatic models includes the Moho, which is based on existing seismic determinations. Additional compensation is provided by density variations within the lithosphere (chiefly in the upper mantle). In this way we minimize regional anomalies over the Arabian plate. The residual local anomalies well correspond to tectonic structure of the plate. Still very significant anomalies are associated with the Zagros fold belt, the collision zone of the Arabian and Eurasian plates.

Investigation of Quasi-periodic Solar Oscillations in Sunspots Based on SOHO/MDI Magnetograms

NASA Astrophysics Data System (ADS)

Kallunki, J.; Riehokainen, A.

2012-10-01

In this work we study quasi-periodic solar oscillations in sunspots, based on the variation of the amplitude of the magnetic field strength and the variation of the sunspot area. We investigate long-period oscillations between three minutes and ten hours. The magnetic field synoptic maps were obtained from the SOHO/MDI. Wavelet (Morlet), global wavelet spectrum (GWS) and fast Fourier transform (FFT) methods are used in the periodicity analysis at the 95 % significance level. Additionally, the quiet Sun area (QSA) signal and an instrumental effect are discussed. We find several oscillation periods in the sunspots above the 95 % significance level: 3 - 5, 10 - 23, 220 - 240, 340 and 470 minutes, and we also find common oscillation periods (10 - 23 minutes) between the sunspot area variation and that of the magnetic field strength. We discuss possible mechanisms for the obtained results, based on the existing models for sunspot oscillations.

Decadal variation in Earth's oblateness (J2) from satellite laser ranging data

NASA Astrophysics Data System (ADS)

Cheng, Minkang; Ries, John C.

2018-02-01

For four decades, satellite laser ranging has recorded the global nature of the long-wavelength hydrological mass redistribution within the Earth system, which results in significant variations in the Earth's dynamical oblateness, characterized by the second degree zonal geopotential spherical harmonic J2 (or C20). Analysis of the J2 time-series has shown a significant variation related to the strong El Niño-Southern Oscillation events with periods of 2-6 yr. In particular, the variation related to the powerful 2015-2016 El Niño that peaked during 2015 November-December was one of the strongest on record, comparable with the 1982-1983 and 1997-1998 events. In this study, we investigate further the hydrological mass transfer between atmosphere-ocean-land and their signature in the decadal variations of J2 with timescales of ˜10 yr. We found that the ˜6.4-yr variations can be accounted for by the atmosphere and ocean mass variations based on the improved Atmosphere-Ocean De-aliasing data, and the observed decadal variation in J2 correlates well with the decadal tropical variability characterized by the 5-yr running mean of the El Niño-Southern Oscillation Index, although existing physical models, especially the land water storage, are limited for the purpose of further studies of the excitation.

Enlarged leukocyte referent libraries can explain additional variance in blood-based epigenome-wide association studies.

PubMed

Kim, Stephanie; Eliot, Melissa; Koestler, Devin C; Houseman, Eugene A; Wetmur, James G; Wiencke, John K; Kelsey, Karl T

2016-09-01

We examined whether variation in blood-based epigenome-wide association studies could be more completely explained by augmenting existing reference DNA methylation libraries. We compared existing and enhanced libraries in predicting variability in three publicly available 450K methylation datasets that collected whole-blood samples. Models were fit separately to each CpG site and used to estimate the additional variability when adjustments for cell composition were made with each library. Calculation of the mean difference in the CpG-specific residual sums of squares error between models for an arthritis, aging and metabolic syndrome dataset, indicated that an enhanced library explained significantly more variation across all three datasets (p < 10(-3)). Pathologically important immune cell subtypes can explain important variability in epigenome-wide association studies done in blood.

Genetic variation in adaptability and pleiotropy in budding yeast

PubMed Central

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

2017-01-01

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

Irregular topography at the Earth’s inner core boundary

PubMed Central

Dai, Zhiyang; Wang, Wei; Wen, Lianxing

2012-01-01

Compressional seismic wave reflected off the Earth’s inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth’s ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4–8 km with a lateral length scale of 2–4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable. PMID:22547788

Irregular topography at the Earth's inner core boundary.

PubMed

Dai, Zhiyang; Wang, Wei; Wen, Lianxing

2012-05-15

Compressional seismic wave reflected off the Earth's inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth's ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4-8 km with a lateral length scale of 2-4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable.

Genetic variation in adaptability and pleiotropy in budding yeast.

PubMed

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

2017-08-17

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

Practice variation in the transfer of premature infants from incubators to open cots in Australian and New Zealand neonatal nurseries: results of an electronic survey.

PubMed

New, Karen; Bogossian, Fiona; East, Christine; Davies, Mark William

2010-06-01

The incubator environment is essential for optimal physiological functioning and development of the premature infant but the infant is ultimately required to make a successful transfer from incubator to open cot in order to be discharged from hospital. Criteria for transfer lack a systematic approach because no clear, specific guideline predominates in clinical practice. Practice variation exists between continents, regions and nurseries in the same countries, but there is no recent review of current practices utilised for transferring premature infants from incubators to open cots. To document current practice for transferring premature infants to open cots in neonatal nurseries. A descriptive, cross-sectional survey. Twenty-two neonatal intensive care units and fifty-six high dependency special care baby units located in public hospitals in Australia and New Zealand. A sample of 78 key clinical nursing leaders (nurse unit managers, clinical nurse consultants or clinical nurse specialists) within neonatal nurseries identified through email or telephone contact. Data were collected using a web-based survey on practice, decision-making and strategies utilised for transferring premature infants from incubators to open cots. Descriptive statistics (frequencies and crosstabs) were used to analyse data. Comparisons between groups were tested for statistical significance using Chi-squared or Fisher's exact test. Significant practice variation between countries was found for only one variable, nursing infants clothed (p=0.011). Processes and practices undertaken similarly in both countries include use of incubator air control mode, current weight criterion, thermal challenging, single-walled incubators and heated mattress systems. Practice variation was significant between neonatal intensive care units and special care baby units for weight range (p=0.005), evidence-based practice (p=0.004), historical nursery practice (p=0.029) and incubator air control mode (p=0.001). Differences in these variables were also found between nurseries in metropolitan and rural locations. Practice variation exists however; many practices are uniformly performed throughout neonatal nurseries in Australian and New Zealand. Commonality was seen between countries and in nurseries with a neonatal intensive care unit. Variation was significant between neonatal intensive care units and special care baby units and nurseries in metropolitan and rural locations. (c) 2009 Elsevier Ltd. All rights reserved.

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

PubMed Central

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

2015-01-01

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

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

PubMed

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

2015-01-01

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

Epicuticular waxes on onion leaves and associated resistance to onion thrips

USDA-ARS?s Scientific Manuscript database

Natural variation exists for amounts and types of epicuticular waxes on onion foliage. Wild-type onion possesses copious amounts of these waxes and is often referred to as “waxy”. The recessively inherited “glossy” phenotype has significantly less wax relative to waxy types and shows resistance to o...

Learning in 2010: Instructional Challenges for Adult Career and Technical Education

ERIC Educational Resources Information Center

Allen, Jeff M.; Bracey, Pamela; Gavrilova, Mariya

2010-01-01

Decades of research into learning have demonstrated that learners are diverse, changing, and adaptable. In this regard, the practice as educators must become flexible and adaptive to meet the wide variation of learning needs. A general consensus exists among educators, businesses, and other stakeholders that there is a significant gap between the…

A Survey of Managed Care Education at Optometry Schools.

ERIC Educational Resources Information Center

Soroka, Mort; Reis, Lesley

2003-01-01

Studied the courses and topics offered at schools of optometry and the total hours devoted to managed care. Responses from the 17 schools of optometry reveal significant variations in curricular coverage of managed care, although a core set of materials was found to exist that could be the basis for more standard curriculum. (SLD)

Generalized Hurst exponent estimates differentiate EEG signals of healthy and epileptic patients

NASA Astrophysics Data System (ADS)

Lahmiri, Salim

2018-01-01

The aim of our current study is to check whether multifractal patterns of the electroencephalographic (EEG) signals of normal and epileptic patients are statistically similar or different. In this regard, the generalized Hurst exponent (GHE) method is used for robust estimation of the multifractals in each type of EEG signals, and three powerful statistical tests are performed to check existence of differences between estimated GHEs from healthy control subjects and epileptic patients. The obtained results show that multifractals exist in both types of EEG signals. Particularly, it was found that the degree of fractal is more pronounced in short variations of normal EEG signals than in short variations of EEG signals with seizure free intervals. In contrary, it is more pronounced in long variations of EEG signals with seizure free intervals than in normal EEG signals. Importantly, both parametric and nonparametric statistical tests show strong evidence that estimated GHEs of normal EEG signals are statistically and significantly different from those with seizure free intervals. Therefore, GHEs can be efficiently used to distinguish between healthy and patients suffering from epilepsy.

Sources of Variation in Creep Testing

NASA Technical Reports Server (NTRS)

Loewenthal, William S.; Ellis, David L.

2011-01-01

Creep rupture is an important material characteristic for the design of rocket engines. It was observed during the characterization of GRCop-84 that the complete data set had nearly 4 orders of magnitude of scatter. This scatter likely confounded attempts to determine how creep performance was influenced by manufacturing. It was unclear if this variation was from the testing, the material, or both. Sources of variation were examined by conducting tests on identically processed specimens at the same specified stresses and temperatures. Significant differences existed between the five constant-load creep frames. The specimen temperature was higher than the desired temperature by as much as 43 C. It was also observed that the temperature gradient was up to 44 C. Improved specimen temperature control minimized temperature variations. The data from additional tests demonstrated that the results from all five frames were comparable. The variation decreased to 1/2 order of magnitude from 2 orders of magnitude for the baseline data set. Independent determination of creep rates in a reference load frame closely matched the creep rates determined after the modifications. Testing in helium tended to decrease the sample temperature gradient, but helium was not a significant improvement over vacuum.

Morphological analysis of Trichomycterus areolatus Valenciennes, 1846 from southern Chilean rivers using a truss-based system (Siluriformes, Trichomycteridae).

PubMed

Colihueque, Nelson; Corrales, Olga; Yáñez, Miguel

2017-01-01

Trichomycterus areolatus Valenciennes, 1846 is a small endemic catfish inhabiting the Andean river basins of Chile. In this study, the morphological variability of three T. areolatus populations, collected in two river basins from southern Chile, was assessed with multivariate analyses, including principal component analysis (PCA) and discriminant function analysis (DFA). It is hypothesized that populations must segregate morphologically from each other based on the river basin that they were sampled from, since each basin presents relatively particular hydrological characteristics. Significant morphological differences among the three populations were found with PCA (ANOSIM test, r = 0.552, p < 0.0001) and DFA (Wilks's λ = 0.036, p < 0.01). PCA accounted for a total variation of 56.16% by the first two principal components. The first Principal Component (PC1) and PC2 explained 34.72 and 21.44% of the total variation, respectively. The scatter-plot of the first two discriminant functions (DF1 on DF2) also validated the existence of three different populations. In group classification using DFA, 93.3% of the specimens were correctly-classified into their original populations. Of the total of 22 transformed truss measurements, 17 exhibited highly significant ( p < 0.01) differences among populations. The data support the existence of T. areolatus morphological variation across different rivers in southern Chile, likely reflecting the geographic isolation underlying population structure of the species.

Hospital and operator variations in drug-eluting stent use: a multi-level analysis of 5967 consecutive patients in Scotland.

PubMed

Austin, David; Oldroyd, Keith G; McConnachie, Alex; Slack, Rachel; Eteiba, Hany; Flapan, Andrew D; Jennings, Kevin P; Northcote, Robin J; Pell, Alistair C H; Starkey, Ian R; Pell, Jill P

2008-06-01

To determine whether drug-eluting stent (DES) use varies among Scottish hospitals, and the extent to which any variations are explained by differences between operators, patients and lesions. Multi-level analysis of consecutive patients treated with percutaneous coronary intervention (PCI) between April 2005 and March 2006 in Scotland, using the Scottish Coronary Revascularization Registry. A total of 38 operators performed 5967 PCI procedures on 8489 lesions. Crude level of DES use was 47.6%, and the results varied among hospitals (range 30.6-61.8%, chi(2) = 341.6, P < 0.0001). There was significant between-operator variation in the null model. This was attenuated by the addition of hospital as a fixed effect. Nonetheless, the final model demonstrated significant between-operator variability [sigma(2) = 0.486 (0.249-0.971)] and between-hospital variation, after case-mix adjustment. Within Scotland, marked variation existed among hospitals in the use of DES. Operator was the most important factor at patient level, and hospital of treatment, rather than case-mix, was the most important modifier of between-operator variation. Patient selection for DES is complex and may contribute to much of the variations demonstrated. Consensus criteria would provide more detail than is included in current guidance, may aid decision-making for individual patients, reduce opportunity costs and ensure equity of access.

Geographic Variation of Chronic Kidney Disease Prevalence: Correlation with the Incidence of Renal Cell Carcinoma or Urothelial Carcinoma?

PubMed

Yap, Yit-Sheung; Chuang, Kai-Wen; Chiang, Chun-Ju; Chuang, Hung-Yi; Lu, Sheng-Nan

2015-01-01

The aim of this study is to evaluate whether geographic variations in the prevalence of late-stage chronic kidney disease (CKD) exist and are associated with incidence rates of renal cell carcinoma (RCC), upper tract urothelial carcinoma (UTUC), or lower tract urothelial carcinoma (LTUC). Prevalence rates of late-stage CKD for 366 townships (n > 30) in Taiwan were calculated for 1,518,241 and 1,645,151 subjects aged 40 years or older in years 2010 and 2009, respectively. Late-stage CKD prevalence in year 2010 was used as a training set and its age-adjusted standardized morbidity rates (ASMR) were divided into three groups as defined <1.76%, 1.76% ≤ ASMR < 2.64%, and ≥2.64%, respectively. Year 2009, defined as the validation set, was used to validate the results. The ASMR of late-stage CKD in years 2010 and 2009 were 1.76%, and 2.09%, respectively. Geographic variations were observed, with notably higher rates of disease in areas of the central, southwestern mountainside, and southeastern seaboard. There were no significant differences among different combined risk groups of RCC, UTUC, and LTUC incidence. The substantial geographic variations in the prevalence of late-stage CKD exist, but are not correlated with RCC, UTUC, or LTUC incidence.

Midwestern streamflow, precipitation, and atmospheric vorticity influenced by Pacific sea-surface temperatures and total solar-irradiance variations

USGS Publications Warehouse

Perry, C.A.

2006-01-01

A solar effect on streamflow in the Midwestern United States is described and supported in a six-step physical connection between total solar irradiance (TSI), tropical sea-surface temperatures (SSTs), extratropical SSTs, jet-stream vorticity, surface-layer vorticity, precipitation, and streamflow. Variations in the correlations among the individual steps indicate that the solar/hydroclimatic mechanism is complex and has a time element (lag) that may not be constant. Correct phasing, supported by consistent spectral peaks between 0.092 and 0.096 cycles per year in all data sets within the mechanism is strong evidence for its existence. A significant correlation exists between total solar irradiance and the 3-year moving average of annual streamflow for Iowa (R = 0.67) and for the Mississippi River at St Louis, Missouri (R = 0.60), during the period 1950-2000. Published in 2005 by John Wiley & Sons, Ltd.

Gender Gaps and Gendered Action in a First-Year Physics Laboratory

ERIC Educational Resources Information Center

Day, James; Stang, Jared B.; Holmes, N. G.; Kumar, Dhaneesh; Bonn, D. A.

2016-01-01

It is established that male students outperform female students on almost all commonly used physics concept inventories. However, there is significant variation in the factors that contribute to the gap, as well as the direction in which they influence it. It is presently unknown if such a gender gap exists on the relatively new Concise Data…

Natural and induced variation in tomato fruit: an assessment of substantial equivalence relative to stakeholder acceptable chemical diversity

USDA-ARS?s Scientific Manuscript database

Unintended effects to food quality and composition occur no matter the method of plant improvement. The existence of unintended effects is perhaps not the most important point within the discussion, but rather the identity and significance of the compositional changes observed. Here we report the ex...

How College Shapes Lives: Understanding the Issues. Trends in Higher Education Series

ERIC Educational Resources Information Center

Baum, Sandy; Kurose, Charles; Ma, Jennifer

2013-01-01

This report explains some of the ways the payoff of postsecondary education can be measured and provides insights into why there is confusion about that payoff, despite strong evidence. Focusing on the variation in outcomes across individuals helps to clarify that the existence of the high average payoff, and the reality of significant benefits…

On the atmospheric photochemistry of nitric acid

NASA Technical Reports Server (NTRS)

Austin, J.; Garcia, R. R.; Russell, J. M., III; Solomon, S.; Tuck, A. F.

1986-01-01

Measurements of the temporal and spatial variations in HNO3, particularly those from the Nimbus 7 limb IR monitor of the stratosphere (LIMS) satellite experiment, are compared to both a two-dimensional chemical/dynamical model and to chemistry/parcel trajectory analyses. Significant discrepancies are found between the observed and modeled variations in the winter season, especially in the polar night region. The study of the evolution of HNO3 suggests that an important source exists for this species in the high-latitude winter stratosphere that is not included in presently accepted photochemical schemes. Possible reactions to account for this discrepancy are explored.

Regional Variation in Antenatal Corticosteroid Use: A Network-Level Quality Improvement Study

PubMed Central

Goldstein, B.A.; Tamaresis, J.; Kan, P.; Lee, H.C.

2015-01-01

BACKGROUND AND OBJECTIVES: Examination of regional care patterns in antenatal corticosteroid use (ACU) rates may be salient for the development of targeted interventions. Our objective was to assess network-level variation using California perinatal care regions as a proxy. We hypothesized that (1) significant variation in ACU exists within and between California perinatal care regions, and (2) lower performing regions exhibit greater NICU-level variability in ACU than higher performing regions. METHODS: We undertook cross-sectional analysis of 33 610 very low birth weight infants cared for at 120 hospitals in 11 California perinatal care regions from 2005 to 2011. We computed risk-adjusted median ACU rates and interquartile ranges (IQR) for each perinatal care region. The degree of variation was assessed using hierarchical multivariate regression analysis with NICU as a random effect and region as a fixed effect. RESULTS: From 2005 to 2011, mean ACU rates across California increased from 82% to 87.9%. Regional median (IQR) ACU rates ranged from 68.4% (24.3) to 92.9% (4.8). We found significant variation in ACU rates among regions (P < .0001). Compared with Level IV NICUs, care in a lower level of care was a strongly significant predictor of lower odds of receiving antenatal corticosteroids in a multilevel model (Level III, 0.65 [0.45–0.95]; Level II, 0.39 [0.24–0.64]; P < .001). Regions with lower performance in ACU exhibited greater variability in performance. CONCLUSIONS: We found significant variation in ACU rates among California perinatal regions. Regional quality improvement approaches may offer a new avenue to spread best practice. PMID:25601974

Inherited differences in crossing over and gene conversion frequencies between wild strains of Sordaria fimicola from "Evolution Canyon".

PubMed Central

Saleem, M; Lamb, B C; Nevo, E

2001-01-01

Recombination generates new combinations of existing genetic variation and therefore may be important in adaptation and evolution. We investigated whether there was natural genetic variation for recombination frequencies and whether any such variation was environment related and possibly adaptive. Crossing over and gene conversion frequencies often differed significantly in a consistent direction between wild strains of the fungus Sordaria fimicola isolated from a harsher or a milder microscale environment in "Evolution Canyon," Israel. First- and second-generation descendants from selfing the original strains from the harsher, more variable, south-facing slope had higher frequencies of crossing over in locus-centromere intervals and of gene conversion than those from the lusher north-facing slopes. There were some significant differences between strains within slopes, but these were less marked than between slopes. Such inherited variation could provide a basis for natural selection for optimum recombination frequencies in each environment. There were no significant differences in meiotic hybrid DNA correction frequencies between strains from the different slopes. The conversion analysis was made using only conversions to wild type, because estimations of conversion to mutant were affected by a high frequency of spontaneous mutation. There was no polarized segregation of chromosomes at meiosis I or of chromatids at meiosis II. PMID:11779798

Inherited differences in crossing over and gene conversion frequencies between wild strains of Sordaria fimicola from "Evolution Canyon".

PubMed

Saleem, M; Lamb, B C; Nevo, E

2001-12-01

Recombination generates new combinations of existing genetic variation and therefore may be important in adaptation and evolution. We investigated whether there was natural genetic variation for recombination frequencies and whether any such variation was environment related and possibly adaptive. Crossing over and gene conversion frequencies often differed significantly in a consistent direction between wild strains of the fungus Sordaria fimicola isolated from a harsher or a milder microscale environment in "Evolution Canyon," Israel. First- and second-generation descendants from selfing the original strains from the harsher, more variable, south-facing slope had higher frequencies of crossing over in locus-centromere intervals and of gene conversion than those from the lusher north-facing slopes. There were some significant differences between strains within slopes, but these were less marked than between slopes. Such inherited variation could provide a basis for natural selection for optimum recombination frequencies in each environment. There were no significant differences in meiotic hybrid DNA correction frequencies between strains from the different slopes. The conversion analysis was made using only conversions to wild type, because estimations of conversion to mutant were affected by a high frequency of spontaneous mutation. There was no polarized segregation of chromosomes at meiosis I or of chromatids at meiosis II.

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

USGS Publications Warehouse

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

2011-01-01

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

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

NASA Astrophysics Data System (ADS)

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

2014-12-01

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

"They Have to Adapt to Learn": Surgeons' Perspectives on the Role of Procedural Variation in Surgical Education.

PubMed

Apramian, Tavis; Cristancho, Sayra; Watling, Chris; Ott, Michael; Lingard, Lorelei

2016-01-01

Clinical research increasingly acknowledges the existence of significant procedural variation in surgical practice. This study explored surgeons' perspectives regarding the influence of intersurgeon procedural variation on the teaching and learning of surgical residents. This qualitative study used a grounded theory-based analysis of observational and interview data. Observational data were collected in 3 tertiary care teaching hospitals in Ontario, Canada. Semistructured interviews explored potential procedural variations arising during the observations and prompts from an iteratively refined guide. Ongoing data analysis refined the theoretical framework and informed data collection strategies, as prescribed by the iterative nature of grounded theory research. Our sample included 99 hours of observation across 45 cases with 14 surgeons. Semistructured, audio-recorded interviews (n = 14) occurred immediately following observational periods. Surgeons endorsed the use of intersurgeon procedural variations to teach residents about adapting to the complexity of surgical practice and the norms of surgical culture. Surgeons suggested that residents' efforts to identify thresholds of principle and preference are crucial to professional development. Principles that emerged from the study included the following: (1) knowing what comes next, (2) choosing the right plane, (3) handling tissue appropriately, (4) recognizing the abnormal, and (5) making safe progress. Surgeons suggested that learning to follow these principles while maintaining key aspects of surgical culture, like autonomy and individuality, are important social processes in surgical education. Acknowledging intersurgeon variation has important implications for curriculum development and workplace-based assessment in surgical education. Adapting to intersurgeon procedural variations may foster versatility in surgical residents. However, the existence of procedural variations and their active use in surgeons' teaching raises questions about the lack of attention to this form of complexity in current workplace-based assessment strategies. Failure to recognize the role of such variations may threaten the implementation of competency-based medical education in surgery. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

“They Have to Adapt to Learn”: Surgeons’ Perspectives on the Role of Procedural Variation in Surgical Education

PubMed Central

Apramian, Tavis; Cristancho, Sayra; Watling, Chris; Ott, Michael; Lingard, Lorelei

2017-01-01

OBJECTIVE Clinical research increasingly acknowledges the existence of significant procedural variation in surgical practice. This study explored surgeons’ perspectives regarding the influence of intersurgeon procedural variation on the teaching and learning of surgical residents. DESIGN AND SETTING This qualitative study used a grounded theory-based analysis of observational and interview data. Observational data were collected in 3 tertiary care teaching hospitals in Ontario, Canada. Semistructured interviews explored potential procedural variations arising during the observations and prompts from an iteratively refined guide. Ongoing data analysis refined the theoretical framework and informed data collection strategies, as prescribed by the iterative nature of grounded theory research. PARTICIPANTS Our sample included 99 hours of observation across 45 cases with 14 surgeons. Semistructured, audio-recorded interviews (n = 14) occurred immediately following observational periods. RESULTS Surgeons endorsed the use of intersurgeon procedural variations to teach residents about adapting to the complexity of surgical practice and the norms of surgical culture. Surgeons suggested that residents’ efforts to identify thresholds of principle and preference are crucial to professional development. Principles that emerged from the study included the following: (1) knowing what comes next, (2) choosing the right plane, (3) handling tissue appropriately, (4) recognizing the abnormal, and (5) making safe progress. Surgeons suggested that learning to follow these principles while maintaining key aspects of surgical culture, like autonomy and individuality, are important social processes in surgical education. CONCLUSIONS Acknowledging intersurgeon variation has important implications for curriculum development and workplace-based assessment in surgical education. Adapting to intersurgeon procedural variations may foster versatility in surgical residents. However, the existence of procedural variations and their active use in surgeons’ teaching raises questions about the lack of attention to this form of complexity in current workplace-based assessment strategies. Failure to recognize the role of such variations may threaten the implementation of competency-based medical education in surgery. PMID:26705062

Genetic factors of age-related macular degeneration

PubMed Central

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

2007-01-01

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

Spinal surgery: variations in health care costs and implications for episode-based bundled payments.

PubMed

Ugiliweneza, Beatrice; Kong, Maiying; Nosova, Kristin; Huang, Kevin T; Babu, Ranjith; Lad, Shivanand P; Boakye, Maxwell

2014-07-01

Retrospective, observational. To simulate what episodes of care in spinal surgery might look like in a bundled payment system and to evaluate the associated costs and characteristics. Episode-based payment bundling has received considerable attention as a potential method to help curb the rise in health care spending and is being investigated as a new payment model as part of the Affordable Care Act. Although earlier studies investigated bundled payments in a number of surgical settings, very few focused on spine surgery, specifically. We analyzed data from MarketScan. Patients were included in the study if they underwent cervical or lumbar spinal surgery during 2000-2009, had at least 2-year preoperative and 90-day postoperative follow-up data. Patients were grouped on the basis of their diagnosis-related group (DRG) and then tracked in simulated episodes-of-care/payment bundles that lasted for the duration of 30, 60, and 90 days after the discharge from the index-surgical hospitalization. The total cost associated with each episode-of-care duration was measured and characterized. A total of 196,918 patients met our inclusion criteria. Significant variation existed between DRGs, ranging from $11,180 (30-day bundle, DRG 491) to $107,642 (30-day bundle, DRG 456). There were significant cost variations within each individual DRG. Postdischarge care accounted for a relatively small portion of overall bundle costs (range, 4%-8% in 90-day bundles). Total bundle costs remained relatively flat as bundle-length increased (total average cost of 30-day bundle: $33,522 vs. $35,165 for 90-day bundle). Payments to hospitals accounted for the largest portion of bundle costs (76%). There exists significant variation in total health care costs for patients who undergo spinal surgery, even within a given DRG. Better characterization of impacts of a bundled payment system in spine surgery is important for understanding the costs of index procedure hospital, physician services, and postoperative care on potential future health care policy decision making. N/A.

Obstructive sleep apnoea increases the incidence of morning peak of onset in acute myocardial infarction

PubMed Central

Henmi, Tomoko; Minami, Kazutoshi; Uchida, Yuzou; Shiraishi, Yoshinori; Nunohiro, Tatsuya; Maemura, Koji

2013-01-01

Aims: There exists a discrepancy regarding the relationship between obstructive sleep apnoea (OSA) and circadian variation during the onset of acute myocardial infarction (MI). We hypothesized that OSA patients show a characteristic circadian variation and that the severity of OSA significantly affects this variation. Methods and results: The present study included 288 patients with first acute MI who underwent percutaneous coronary intervention within 12 h of symptom onset. The diagnosis of OSA required an apnoea–hypopnoea index (AHI) of ≥5 events/h. A total of 216 patients fulfilled the OSA criteria. The incidence of MI onset between 06:00 and 11:59 hours was significantly higher in OSA patients than in control patients (38 vs. 25%, p=0.039). Circadian variation in the morning peak of MI onset was attenuated in mild OSA (as defined by AHI, 5.0–14.9 events/h; 33 vs. 25%, p=0.240). Moderate-to-severe OSA (as defined by AHI ≥15.0 events/h) clearly increased the incidence of MI onset between 06:00 and 11:59 hours (43 vs. 25%, p=0.014). Multiple logistic regression adjusting for AHI (≥15.0 events/h), age, body mass index, hypertension, and current smoking showed that moderate-to-severe OSA significantly contributed to MI onset between 06:00 and 11:59 hours (odds ratio 2.00, p=0.010). Conclusions: OSA showed a morning peak with regard to MI onset, and moderate-to-severe OSA significantly enhanced this circadian variation. PMID:24222825

Lunar and Solar Torques on the Oceanic Tides

NASA Technical Reports Server (NTRS)

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

1998-01-01

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

Interindividual variation in thermal sensitivity of maximal sprint speed, thermal behavior, and resting metabolic rate in a lizard.

PubMed

Artacho, Paulina; Jouanneau, Isabelle; Le Galliard, Jean-François

2013-01-01

Studies of the relationship of performance and behavioral traits with environmental factors have tended to neglect interindividual variation even though quantification of this variation is fundamental to understanding how phenotypic traits can evolve. In ectotherms, functional integration of locomotor performance, thermal behavior, and energy metabolism is of special interest because of the potential for coadaptation among these traits. For this reason, we analyzed interindividual variation, covariation, and repeatability of the thermal sensitivity of maximal sprint speed, preferred body temperature, thermal precision, and resting metabolic rate measured in ca. 200 common lizards (Zootoca vivipara) that varied by sex, age, and body size. We found significant interindividual variation in selected body temperatures and in the thermal performance curve of maximal sprint speed for both the intercept (expected trait value at the average temperature) and the slope (measure of thermal sensitivity). Interindividual differences in maximal sprint speed across temperatures, preferred body temperature, and thermal precision were significantly repeatable. A positive relationship existed between preferred body temperature and thermal precision, implying that individuals selecting higher temperatures were more precise. The resting metabolic rate was highly variable but was not related to thermal sensitivity of maximal sprint speed or thermal behavior. Thus, locomotor performance, thermal behavior, and energy metabolism were not directly functionally linked in the common lizard.

Existence of evolutionary variational solutions via the calculus of variations

NASA Astrophysics Data System (ADS)

Bögelein, Verena; Duzaar, Frank; Marcellini, Paolo

In this paper we introduce a purely variational approach to time dependent problems, yielding the existence of global parabolic minimizers, that is ∫0T ∫Ω [uṡ∂tφ+f(x,Du)] dx dt⩽∫0T ∫Ω f(x,Du+Dφ) dx dt, whenever T>0 and φ∈C0∞(Ω×(0,T),RN). For the integrand f:Ω×R→[0,∞] we merely assume convexity with respect to the gradient variable and coercivity. These evolutionary variational solutions are obtained as limits of maps depending on space and time minimizing certain convex variational functionals. In the simplest situation, with some growth conditions on f, the method provides the existence of global weak solutions to Cauchy-Dirichlet problems of parabolic systems of the type ∂tu-divDξf(x,Du)=0 in Ω×(0,∞).

Case-mix fails to explain variation in mastectomy rates: management of screen-detected breast cancer in a UK region 1997–2003

PubMed Central

Caldon, L J M; Walters, S J; Reed, J A; Murphy, A; Worley, A; Reed, M W R

2004-01-01

Wide variation in the surgical management of breast cancer exists at hospital, regional, national and international level. To demonstrate whether variation in surgical practice observed at aggregate level between breast units persists following adjustment for case-mix, individual patient-level data from the Trent Breast Screening Programme Quality Assurance database (1997–2003) was analysed. Expected case-mix adjusted mastectomy rates were derived by logistic regression using the variables tumour size, site and grade, patient age and year of presentation, employing the region's overall case-mix adjusted practice as the reference population. The region's 11 breast screening units detected 5109 (3989 invasive) surgically managed primary breast cancers over the 6-year period. A total of 1828 mastectomies (Mx) were performed (Mx rate 35.8%, 95% confidence interval: 34.5–37.1%). Significant variation in mastectomy rates were observed between units (range 25–45%, P<0.0001), and persists following case-mix adjustment (P<0.0001). Two-fold variation in observed to expected unit mastectomy rate coefficient is demonstrated overall (range 0.66–1.36), increasing to almost four-fold variation in cancers less than 15 mm diameter (range 0.55–1.95). Significant variation in surgery for screen-detected primary breast cancer is not explained by case-mix. Further research is required to investigate potential patient and professional causative factors. PMID:15611797

Lower thermosphere (80-100 km) dynamics response to solar and geomagnetic activity: Overview

NASA Technical Reports Server (NTRS)

Kazimirovsky, E. S.

1989-01-01

The variations of solar and geomagnetic activity may affect the thermosphere circulation via plasma heating and electric fields, especially at high latitudes. The possibility exists that the energy involved in auroral and magnetic storms can produce significant changes of mesosphere and lower thermosphere wind systems. A study of global radar measurements of winds at 80 to 100 km region revealed the short term effects (correlation between wind field and geomagnetic storms) and long term variations over a solar cycle. It seems likely that the correlation results from a modification of planetary waves and tides propagated from below, thus altering the dynamical regime of the thermosphere. Sometimes the long term behavior points rather to a climatic variation with the internal atmospheric cause than to a direct solar control.

Reimbursement for critical care services in India

PubMed Central

Jayaram, Raja; Ramakrishnan, Nagarajan

2013-01-01

There are significant variations in critical care practices, costs, and reimbursements in various countries. Of note, there is a paucity of reliable information on remuneration and reimbursement models for intensivists in India. This review article aims to analyze the existing reimbursement models in United States and United Kingdom and propose a frame-work model that may be applicable in India. PMID:23833469

Discriminating disturbance from natural variation with LiDAR in semi-arid forests in the southwestern USA

Treesearch

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

2015-01-01

Discriminating amongst spatial configurations and climax size of trees in forests along varying physical gradients from time since last disturbance is a significant component of applied forest management. Understanding what has led to the existing vegetation’s structure has important implications for monitoring succession and eco-hydrological interactions within the...

The limits to equivalent living conditions: regional disparities in premature mortality in Germany.

PubMed

Plümper, Thomas; Laroze, Denise; Neumayer, Eric

2018-01-01

Despite the country's explicit political goal to establish equivalent living conditions across Germany, significant inequality continues to exist. We argue that premature mortality is an excellent proxy variable for testing the claim of equivalent living conditions since the root causes of premature death are socioeconomic. We analyse variation in premature mortality across Germany's 402 districts and cities in 2014. Premature mortality spatially clusters among geographically contiguous and proximate districts/cities and is higher in more urban places as well as in districts/cities located further north and in former East Germany. We demonstrate that, first, socioeconomic factors account for 62% of the cross-sectional variation in years of potential life lost and 70% of the variation in the premature mortality rate. Second, we show that these socioeconomic factors either entirely or almost fully eliminate the systematic spatial patterns that exist in premature mortality. On its own, fiscal redistribution, the centrepiece of how Germany aspires to establish its political goal, cannot generate equivalent living conditions in the absence of a comprehensive set of economic and social policies at all levels of political administration, tackling the disparities in socioeconomic factors that collectively result in highly unequal living conditions.

Rapid Detection of Positive Selection in Genes and Genomes Through Variation Clusters

PubMed Central

Wagner, Andreas

2007-01-01

Positive selection in genes and genomes can point to the evolutionary basis for differences among species and among races within a species. The detection of positive selection can also help identify functionally important protein regions and thus guide protein engineering. Many existing tests for positive selection are excessively conservative, vulnerable to artifacts caused by demographic population history, or computationally very intensive. I here propose a simple and rapid test that is complementary to existing tests and that overcomes some of these problems. It relies on the null hypothesis that neutrally evolving DNA regions should show a Poisson distribution of nucleotide substitutions. The test detects significant deviations from this expectation in the form of variation clusters, highly localized groups of amino acid changes in a coding region. In applying this test to several thousand human–chimpanzee gene orthologs, I show that such variation clusters are not generally caused by relaxed selection. They occur in well-defined domains of a protein's tertiary structure and show a large excess of amino acid replacement over silent substitutions. I also identify multiple new human–chimpanzee orthologs subject to positive selection, among them genes that are involved in reproductive functions, immune defense, and the nervous system. PMID:17603100

Serological Relationships Among Feline Caliciviruses

PubMed Central

Povey, R. C.

1974-01-01

A total of 46 strains of feline calicivirus isolates from the United Kingdom, United States, Australia, and New Zealand were used in an investigation of their serological relationships based on the serum neutralization test. Although demonstrable antigenic variation exists between these isolates, it is shown that significant in vitro cross-activity exists between all these isolates to greater or lesser extent. All isolates tested may be regarded as serological variants of a single serotype of feline calicivirus. It is postulated that this relationship would provide for considerable cross-protection during successive exposures of cats to various feline caliciviruses. PMID:4435957

Morphological analysis of Trichomycterus areolatus Valenciennes, 1846 from southern Chilean rivers using a truss-based system (Siluriformes, Trichomycteridae)

PubMed Central

Colihueque, Nelson; Corrales, Olga; Yáñez, Miguel

2017-01-01

Abstract Trichomycterus areolatus Valenciennes, 1846 is a small endemic catfish inhabiting the Andean river basins of Chile. In this study, the morphological variability of three T. areolatus populations, collected in two river basins from southern Chile, was assessed with multivariate analyses, including principal component analysis (PCA) and discriminant function analysis (DFA). It is hypothesized that populations must segregate morphologically from each other based on the river basin that they were sampled from, since each basin presents relatively particular hydrological characteristics. Significant morphological differences among the three populations were found with PCA (ANOSIM test, r = 0.552, p < 0.0001) and DFA (Wilks’s λ = 0.036, p < 0.01). PCA accounted for a total variation of 56.16% by the first two principal components. The first Principal Component (PC1) and PC2 explained 34.72 and 21.44% of the total variation, respectively. The scatter-plot of the first two discriminant functions (DF1 on DF2) also validated the existence of three different populations. In group classification using DFA, 93.3% of the specimens were correctly-classified into their original populations. Of the total of 22 transformed truss measurements, 17 exhibited highly significant (p < 0.01) differences among populations. The data support the existence of T. areolatus morphological variation across different rivers in southern Chile, likely reflecting the geographic isolation underlying population structure of the species. PMID:29134012

Comparing NICU teamwork and safety climate across two commonly used survey instruments

PubMed Central

Profit, Jochen; Lee, Henry C; Sharek, Paul J; Kan, Peggy; Nisbet, Courtney C; Thomas, Eric J; Etchegaray, Jason M; Sexton, Bryan

2016-01-01

Background and objectives Measurement and our understanding of safety culture are still evolving. The objectives of this study were to assess variation in safety and teamwork climate and in the neonatal intensive care unit (NICU) setting, and compare measurement of safety culture scales using two different instruments (Safety Attitudes Questionnaire (SAQ) and Hospital Survey on Patient Safety Culture (HSOPSC)). Methods Cross-sectional survey study of a voluntary sample of 2073 (response rate 62.9%) health professionals in 44 NICUs. To compare survey instruments, we used Spearman's rank correlation coefficients. We also compared similar scales and items across the instruments using t tests and changes in quartile-level performance. Results We found significant variation across NICUs in safety and teamwork climate scales of SAQ and HSOPSC (p<0.001). Safety scales (safety climate and overall perception of safety) and teamwork scales (teamwork climate and teamwork within units) of the two instruments correlated strongly (safety r=0.72, p<0.001; teamwork r=0.67, p<0.001). However, the means and per cent agreements for all scale scores and even seemingly similar item scores were significantly different. In addition, comparisons of scale score quartiles between the two instruments revealed that half of the NICUs fell into different quartiles when translating between the instruments. Conclusions Large variation and opportunities for improvement in patient safety culture exist across NICUs. Important systematic differences exist between SAQ and HSOPSC such that these instruments should not be used interchangeably. PMID:26700545

Seasonal Variation in Penicillin Use in Mexico and Brazil: Analysis of the Impact of Over-the-Counter Restrictions

PubMed Central

Santa-Ana-Tellez, Yared; Mantel-Teeuwisse, Aukje K.; Leufkens, Hubert G. M.

2014-01-01

During 2010, Mexico and Brazil implemented policies to enforce existing laws of restricting over-the-counter sales of antibiotics. We determined if the enforcement led to more appropriate antibiotic use by measuring changes in seasonal variation of penicillin use. We used retail quarterly sales data in defined daily doses per 1,000 inhabitant-days (DDD/TID) from IMS Health from the private sector in Mexico and Brazil from the first quarter of 2007 to the first quarter of 2013. This database contains information on volume of antibiotics sold in retail pharmacies using information from wholesalers. We used interrupted time-series models controlling for external factors with the use of antihypertensives with interaction terms to assess changes in trend, level, and variation in use between quarters for total penicillin use and by active substance. The most used penicillin was amoxicillin, followed by amoxicillin-clavulanic acid and ampicillin (minimal use in Brazil). Before the restrictions, the seasonal variation in penicillin use was 1.1 DDD/TID in Mexico and 0.8 DDD/TID in Brazil. In Mexico, we estimated a significant decrease in the seasonal variation of 0.4 DDD/TID after the restriction, mainly due to changes in seasonal variation of amoxicillin and ampicillin. In Brazil, the seasonal variation did not change significantly, overall and in the breakdown by individual active substances. For Mexico, inappropriate penicillin use may have diminished after the restrictions were enforced. For Brazil, increasing use and no change in seasonal variation suggest that further efforts are needed to reduce inappropriate penicillin use. PMID:25313222

Geographic Variation of Chronic Kidney Disease Prevalence: Correlation with the Incidence of Renal Cell Carcinoma or Urothelial Carcinoma?

PubMed Central

Yap, Yit-Sheung; Chuang, Kai-Wen; Chiang, Chun-Ju; Chuang, Hung-Yi

2015-01-01

Background. The aim of this study is to evaluate whether geographic variations in the prevalence of late-stage chronic kidney disease (CKD) exist and are associated with incidence rates of renal cell carcinoma (RCC), upper tract urothelial carcinoma (UTUC), or lower tract urothelial carcinoma (LTUC). Methods. Prevalence rates of late-stage CKD for 366 townships (n > 30) in Taiwan were calculated for 1,518,241 and 1,645,151 subjects aged 40 years or older in years 2010 and 2009, respectively. Late-stage CKD prevalence in year 2010 was used as a training set and its age-adjusted standardized morbidity rates (ASMR) were divided into three groups as defined <1.76%, 1.76% ≤ ASMR < 2.64%, and ≥2.64%, respectively. Year 2009, defined as the validation set, was used to validate the results. Results. The ASMR of late-stage CKD in years 2010 and 2009 were 1.76%, and 2.09%, respectively. Geographic variations were observed, with notably higher rates of disease in areas of the central, southwestern mountainside, and southeastern seaboard. There were no significant differences among different combined risk groups of RCC, UTUC, and LTUC incidence. Conclusion. The substantial geographic variations in the prevalence of late-stage CKD exist, but are not correlated with RCC, UTUC, or LTUC incidence. PMID:26605329

Interindividual and intraindividual variations in postprandial glycemia peak time complicate precise recommendations for self-monitoring of glucose in persons with type 1 diabetes mellitus.

PubMed

Johansen, Mette Dencker; Gjerløv, Irene; Christiansen, Jens Sandahl; Hejlesen, Ole K

2012-03-01

In glycemic control, postprandial glycemia may be important to monitor and optimize as it reveals glycemic control quality, and postprandial hyperglycemia partly predicts late diabetic complications. Self-monitoring of blood glucose (SMBG) may be an appropriate technology to use, but recommendations on measurement time are crucial. We retrospectively analyzed interindividual and intraindividual variations in postprandial glycemic peak time. Continuous glucose monitoring (CGM) and carbohydrate intake were collected in 22 patients with type 1 diabetes mellitus. Meals were identified from carbohydrate intake data. For each meal, peak time was identified as time from meal to CGM zenith within 40-150 min after meal start. Interindividual (one-way Anova) and intraindividual (intraclass correlation coefficient) variation was calculated. Nineteen patients were included with sufficient meal data quality. Mean peak time was 87 ± 29 min. Mean peak time differed significantly between patients (p = 0.02). Intraclass correlation coefficient was 0.29. Significant interindividual and intraindividual variations exist in postprandial glycemia peak time, thus hindering simple and general advice regarding postprandial SMBG for detection of maximum values. © 2012 Diabetes Technology Society.

From symmetry to asymmetry: Phylogenetic patterns of asymmetry variation in animals and their evolutionary significance

PubMed Central

Palmer, A. Richard

1996-01-01

Phylogenetic analyses of asymmetry variation offer a powerful tool for exploring the interplay between ontogeny and evolution because (i) conspicuous asymmetries exist in many higher metazoans with widely varying modes of development, (ii) patterns of bilateral variation within species may identify genetically and environmentally triggered asymmetries, and (iii) asymmetries arising at different times during development may be more sensitive to internal cytoplasmic inhomogeneities compared to external environmental stimuli. Using four broadly comparable asymmetry states (symmetry, antisymmetry, dextral, and sinistral), and two stages at which asymmetry appears developmentally (larval and postlarval), I evaluated relations between ontogenetic and phylogenetic patterns of asymmetry variation. Among 140 inferred phylogenetic transitions between asymmetry states, recorded from 11 classes in five phyla, directional asymmetry (dextral or sinistral) evolved directly from symmetrical ancestors proportionally more frequently among larval asymmetries. In contrast, antisymmetry, either as an end state or as a transitional stage preceding directional asymmetry, was confined primarily to postlarval asymmetries. The ontogenetic origin of asymmetry thus significantly influences its subsequent evolution. Furthermore, because antisymmetry typically signals an environmentally triggered asymmetry, the phylogenetic transition from antisymmetry to directional asymmetry suggests that many cases of laterally fixed asymmetries evolved via genetic assimilation. PMID:8962039

Repeatability of circadian behavioural variation revealed in free-ranging marine fish.

PubMed

Alós, Josep; Martorell-Barceló, Martina; Campos-Candela, Andrea

2017-02-01

Repeatable between-individual differences in the behavioural manifestation of underlying circadian rhythms determine chronotypes in humans and terrestrial animals. Here, we have repeatedly measured three circadian behaviours, awakening time, rest onset and rest duration, in the free-ranging pearly razorfish, Xyrithchys novacula , facilitated by acoustic tracking technology and hidden Markov models. In addition, daily travelled distance, a standard measure of daily activity as fish personality trait, was repeatedly assessed using a State-Space Model. We have decomposed the variance of these four behavioural traits using linear mixed models and estimated repeatability scores ( R ) while controlling for environmental co-variates: year of experimentation, spatial location of the activity, fish size and gender and their interactions. Between- and within-individual variance decomposition revealed significant R s in all traits suggesting high predictability of individual circadian behavioural variation and the existence of chronotypes. The decomposition of the correlations among chronotypes and the personality trait studied here into between- and within-individual correlations did not reveal any significant correlation at between-individual level. We therefore propose circadian behavioural variation as an independent axis of the fish personality, and the study of chronotypes and their consequences as a novel dimension in understanding within-species fish behavioural diversity.

Agreement among dentists' restorative treatment planning thresholds for primary occlusal caries, primary proximal caries, and existing restorations: findings from The National Dental Practice-Based Research Network.

PubMed

Heaven, Tim J; Gordan, Valeria V; Litaker, Mark S; Fellows, Jeffrey L; Brad Rindal, D; Firestone, Allen R; Gilbert, Gregg H

2013-08-01

The aim of this study was to quantify the agreement among individual National Dental Practice-Based Research Network dentists' self-reported treatment decisions for primary occlusal caries, primary proximal caries, and existing restorations. Five hypothetical clinical scenarios were presented: primary occlusal caries; primary proximal caries; and whether three existing restorations should be repaired or replaced. We quantified the probability that dentists who recommended later restorative intervention for primary caries were the same ones who recommended that existing restorations be repaired instead of replaced. Dentists who recommended later restorative treatment of primary occlusal caries and proximal caries at a more-advanced stage were significantly more likely to recommend repair instead of replacement. Agreement among dentists on a threshold stage for the treatment of primary caries ranged from 40 to 68%, while that for repair or replacement of existing restorations was 36 to 43%. Dentists who recommended repair rather than replacement of existing restorations were significantly more likely to recommend later treatment of primary caries. Conversely, dentists who recommended treatment of primary caries at an earlier stage were significantly more likely to recommend replacement of the entire restoration. Between-dentist agreement for primary caries treatment was better than between-dentist agreement for repair or replacement of existing restorations. These findings suggest consistency in how individual dentists approach the treatment of primary caries and existing restorations. However, substantial variation was found between dentists in their treatment decisions about the same teeth. Copyright © 2013 Elsevier Ltd. All rights reserved.

Variation of ecosystem services and human activities: A case study in the Yanhe Watershed of China

NASA Astrophysics Data System (ADS)

Su, Chang-hong; Fu, Bo-Jie; He, Chan-Sheng; Lü, Yi-He

2012-10-01

The concept of 'ecosystem service' provides cohesive views on mechanisms by which nature contributes to human well-being. Fast social and economic development calls for research on interactions between human and natural systems. We took the Yanhe Watershed as our study area, and valued the variation of ecosystem services and human activities of 2000 and 2008. Five ecosystem services were selected i.e. net primary production (NPP), carbon sequestration and oxygen production (CSOP), water conservation, soil conservation, and grain production. Human activity was represented by a composite human activity index (HAI) that integrates human population density, farmland ratio, influence of residential sites and road network. Analysis results of the five ecosystem services and human activity (HAI) are as follows: (i) NPP, CSOP, water conservation, and soil conservation increased from 2000 to 2008, while grain production declined. HAI decreased from 2000 to 2008. Spatially, NPP, CSOP, and water conservation in 2000 and 2008 roughly demonstrated a pattern of decline from south to north, while grain production shows an endocentric increasing spatial pattern. Soil conservation showed a spatial pattern of high in the south and low in the north in 2000 and a different pattern of high in the west and low in the east in 2008 respectively. HAI is proportional to the administrative level and economic development. Variation of NPP/CSOP between 2000 and 2008 show an increasing spatial pattern from northwest to southeast. In contrast, the variation of soil conservation shows an increasing pattern from southeast to northwest. Variation of water conservation shows a fanning out decreasing pattern. Variation of grain production doesn't show conspicuous spatial pattern. (ii) Variation of water conservation and of soil conservation is significantly positively correlated at 0.01 level. Both variations of water conservation and soil conservation are negatively correlated with variation of HAI at 0.01 level. Variations of NPP/CSOP are negatively correlated with variations of soil conservation and grain production at 0.05 level. (iii) Strong tradeoffs exist between regulation services and provision service, while synergies exist within regulation services. Driving effect of human activities on ecosystem services and tradeoffs and synergies among ecosystem service are also discussed.

Isostatic Model and Isostatic Gravity Anomalies of the Arabian Plate and Surroundings

NASA Astrophysics Data System (ADS)

Kaban, Mikhail K.; El Khrepy, Sami; Al-Arifi, Nassir

2016-04-01

The isostatic modeling represents one of the most useful "geological" reduction methods of the gravity field. With the isostatic correction, it is possible to remove a significant part of the effect of deep density heterogeneity, which dominates in the Bouguer gravity anomalies. Although there exist several isostatic compensation schemes, it is usually supposed that a choice of the model is not an important factor to first order, since the total weight of compensating masses remains the same. We compare two alternative models for the Arabian plate and surrounding area. The Airy model gives very significant regional isostatic anomalies, which cannot be explained by the upper crust structure or disturbances of the isostatic equilibrium. Also, the predicted "isostatic" Moho is very different from existing seismic observations. The second isostatic model includes the Moho, which is based on seismic determinations. Additional compensation is provided by density variations within the lithosphere (chiefly in the upper mantle). According to this model, the upper mantle under the Arabian Shield is less dense than under the Platform. In the Arabian platform, the maximum density coincides with the Rub' al Khali, one of the richest oil basin in the world. This finding agrees with previous studies, showing that such basins are often underlain by dense mantle, possibly related to an eclogite layer that has caused their subsidence. The mantle density variations might be also a result of variations of the lithosphere thickness. With the combined isostatic model, it is possible to minimize regional anomalies over the Arabian plate. The residual local anomalies correspond well to tectonic structure of the plate. Still very significant anomalies, showing isostatic disturbances of the lithosphere, are associated with the Zagros fold belt, the collision zone of the Arabian and Eurasian plates.

A new statistic for identifying batch effects in high-throughput genomic data that uses guided principal component analysis.

PubMed

Reese, Sarah E; Archer, Kellie J; Therneau, Terry M; Atkinson, Elizabeth J; Vachon, Celine M; de Andrade, Mariza; Kocher, Jean-Pierre A; Eckel-Passow, Jeanette E

2013-11-15

Batch effects are due to probe-specific systematic variation between groups of samples (batches) resulting from experimental features that are not of biological interest. Principal component analysis (PCA) is commonly used as a visual tool to determine whether batch effects exist after applying a global normalization method. However, PCA yields linear combinations of the variables that contribute maximum variance and thus will not necessarily detect batch effects if they are not the largest source of variability in the data. We present an extension of PCA to quantify the existence of batch effects, called guided PCA (gPCA). We describe a test statistic that uses gPCA to test whether a batch effect exists. We apply our proposed test statistic derived using gPCA to simulated data and to two copy number variation case studies: the first study consisted of 614 samples from a breast cancer family study using Illumina Human 660 bead-chip arrays, whereas the second case study consisted of 703 samples from a family blood pressure study that used Affymetrix SNP Array 6.0. We demonstrate that our statistic has good statistical properties and is able to identify significant batch effects in two copy number variation case studies. We developed a new statistic that uses gPCA to identify whether batch effects exist in high-throughput genomic data. Although our examples pertain to copy number data, gPCA is general and can be used on other data types as well. The gPCA R package (Available via CRAN) provides functionality and data to perform the methods in this article. reesese@vcu.edu

Geophysical variables and behavior: XXI. Geomagnetic variation as possible enhancement stimuli for UFO reports preceding earthtremors.

PubMed

Persinger, M A

1985-02-01

The contribution of geomagnetic variation to the occurrence of UFORs (reports of UFOs) within the New Madrid States during the 6-mo. increments before increases in the numbers of IV-V or less intensity earthquakes within the central USA was determined. Although statistically significant zero-order correlations existed between measures of earthquakes, UFORs and geomagnetic variability, the association between the latter two deteriorated markedly when their shared variance with earthquakes was held constant. These outcomes are compatible with the hypothesis that geomagnetic variability (or phenomena associated with it) may enhance UFORs but only if tectonic stress and strain are increasing within the region.

The formation and effect of outer-ply microcracks in cross-ply laminates - A variational approach

NASA Technical Reports Server (NTRS)

Nairn, John A.; Hu, Shoufeng

1992-01-01

The paper presents a variational mechanics analysis of the stresses and energy release rate in a (90m/0n)s laminate, with account taken of the observed existence of staggered microcracks. It is found that the load required to initiate microcracks is significantly lower for (90m/0n)s laminates than for (0n/90m)s laminates. It is also found that (90m/0n)s laminates are characterized by a lower saturation crack density and that no bending effects tend to promote mode I delamination in (90m/0n)s laminates.

Natural genetic variation of root system architecture from Arabidopsis to Brachypodium: towards adaptive value.

PubMed

Pacheco-Villalobos, David; Hardtke, Christian S

2012-06-05

Root system architecture is a trait that displays considerable plasticity because of its sensitivity to environmental stimuli. Nevertheless, to a significant degree it is genetically constrained as suggested by surveys of its natural genetic variation. A few regulators of root system architecture have been isolated as quantitative trait loci through the natural variation approach in the dicotyledon model, Arabidopsis. This provides proof of principle that allelic variation for root system architecture traits exists, is genetically tractable, and might be exploited for crop breeding. Beyond Arabidopsis, Brachypodium could serve as both a credible and experimentally accessible model for root system architecture variation in monocotyledons, as suggested by first glimpses of the different root morphologies of Brachypodium accessions. Whether a direct knowledge transfer gained from molecular model system studies will work in practice remains unclear however, because of a lack of comprehensive understanding of root system physiology in the native context. For instance, apart from a few notable exceptions, the adaptive value of genetic variation in root system modulators is unknown. Future studies should thus aim at comprehensive characterization of the role of genetic players in root system architecture variation by taking into account the native environmental conditions, in particular soil characteristics.

Variation in Care of Inflammatory Bowel Diseases Patients in Crohn's and Colitis Foundation of America Partners: Role of Gastroenterologist Practice Setting in Disease Outcomes and Quality Process Measures.

PubMed

Weaver, Kimberly N; Kappelman, Michael D; Sandler, Robert S; Martin, Christopher F; Chen, Wenli; Anton, Kristen; Long, Millie D

2016-11-01

As variation in care has previously been linked to quality, we aimed to describe variations in inflammatory bowel diseases care by gastroenterology (GI) practice setting. We performed a cross-sectional study within the Crohn's and Colitis Foundation of America Partners and used bivariate analyses to compare patient characteristics by GI practice setting (GI-academic [GIA], GI-private, or GI-other). Regression models were used to describe the effects of provider type on steroid use, disease activity, and the quality of life. The study included 12,083 patients with inflammatory bowel diseases (7576 with Crohn's disease [CD] and 4507 with ulcerative colitis [UC]). Nearly 95% reported visiting a GI provider annually. Also, CD patients seen by GIA were younger, better educated, used less 5-aminosalicylate agents, and had higher biologic and immunomodulator use (P < 0.001 for all). On multivariate analysis of CD patients, GIA used less steroids when compared with GI-private (odds ratio, 0.84; 95% confidence interval, 0.67-1.06) or GI-other (odds ratio, 0.66; 95% confidence interval, 0.49-0.89). GIA patients were more likely to be in remission, have flu vaccine, and have better quality of life. UC patients seen by GIA were younger, had more hospitalizations, and previous surgery (P < 0.001 for all). No differences existed for steroid use, remission, flu vaccine, or quality of life for UC care on bivariate or multivariate analyses. Significant variations in care patterns and quality measures exist for CD across GI provider types, without similar variation in UC care. Interventions to reduce variations in care could improve the quality of care in CD.

Variations in body weight, food intake and body composition after long-term high-fat diet feeding in C57BL/6J Mice

PubMed Central

Yang, Yongbin; Smith, Daniel L.; Keating, Karen D.; Allison, David B.; Nagy, Tim R.

2014-01-01

Objective To investigate the variations in body weight, food intake and body composition of both male and female C57BL/6J mice during a diet-induced obesity (DIO) model with high-fat diet (HFD) feeding. Design and Methods Mice were individually housed and fed ad libitum either a low-fat diet (LFD, 10% calories from fat; n=15 male, n=15 female) or high-fat diet (HFD, 45% calories from fat; n=277 male, n=278 female) from 8 to 43 weeks of age. Body weight, food intake and body composition were routinely measured. Results Body weight was significantly increased with HFD (vs. LFD) in males from week 14 (p=0.0221) and in females from week 27 (P=0.0076). Fat mass and fat-free mass of all groups were significantly increased over time (all p<0.0001), with a large variation observed in fat mass. Baseline fat mass, fat-free mass and daily energy intake were significant predictors of future body weight for both sexes (p<0.0001). Baseline fat mass was a significant predictor of future body fat (p<0.0001). Conclusions Both males and females have large variations in fat mass, and this variability increases over time, while that of fat-free mass remains relatively stable. Sex differences exist in HFD responses and multivariate predicting models of body weight. PMID:24942674

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

NASA Astrophysics Data System (ADS)

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

2010-10-01

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

Natural acetylation impacts carbohydrate recovery during deconstruction of Populus trichocarpa wood

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

Johnson, Amanda M.; Kim, Hoon; Ralph, John

Significant variation in the inherent degree of acetylation naturally exists in the xylem cell walls of Populus trichocarpa. During pretreatment, endogenous acetate hydrolyzes to acetic acid that can subsequently catalyze the breakdown of poplar wood, increasing the efficiency of biomass pretreatment. Poplar genotypes varying in cell wall composition were pretreated in 0.3% H 2SO 4 in non-isothermal batch reactors. Acetic acid released from the wood was positively related to sugar release during pretreatment ( R ≥ 0.9), and inversely proportional to the lignin content of the poplar wood ( R = 0.6). There is significant variation in wood chemistry amongmore » P. trichocarpa genotypes. As a result, this study elucidated patterns of cell wall deconstruction and clearly links carbohydrate solubilization to acetate release. Tailoring biomass feedstocks for acetate release could enhance pretreatment efficiencies.« less

Ice sheets play important role in climate change

NASA Astrophysics Data System (ADS)

Clark, Peter U.; MacAyeal, Douglas R.; Andrews, John T.; Bartlein, Patrick J.

Ice sheets once were viewed as passive elements in the climate system enslaved to orbitally generated variations in solar radiation. Today, modeling results and new geologic records suggest that ice sheets actively participated in late-Pleistocene climate change, amplifying or driving significant variability at millennial as well as orbital timescales. Although large changes in global ice volume were ultimately caused by orbital variations (the Milankovitch hypothesis), once in existence, the former ice sheets behaved dynamically and strongly influenced regional and perhaps even global climate by altering atmospheric and oceanic circulation and temperature.Experiments with General Circulation Models (GCMs) yielded the first inklings of ice sheets' climatic significance. Manabe and Broccoli [1985], for example, found that the topographic and albedo effects of ice sheets alone explain much of the Northern Hemisphere cooling identified in paleoclimatic records of the last glacial maximum (˜21 ka).

Natural acetylation impacts carbohydrate recovery during deconstruction of Populus trichocarpa wood

DOE PAGES

Johnson, Amanda M.; Kim, Hoon; Ralph, John; ...

2017-02-23

Significant variation in the inherent degree of acetylation naturally exists in the xylem cell walls of Populus trichocarpa. During pretreatment, endogenous acetate hydrolyzes to acetic acid that can subsequently catalyze the breakdown of poplar wood, increasing the efficiency of biomass pretreatment. Poplar genotypes varying in cell wall composition were pretreated in 0.3% H 2SO 4 in non-isothermal batch reactors. Acetic acid released from the wood was positively related to sugar release during pretreatment ( R ≥ 0.9), and inversely proportional to the lignin content of the poplar wood ( R = 0.6). There is significant variation in wood chemistry amongmore » P. trichocarpa genotypes. As a result, this study elucidated patterns of cell wall deconstruction and clearly links carbohydrate solubilization to acetate release. Tailoring biomass feedstocks for acetate release could enhance pretreatment efficiencies.« less

Parabolic Systems with p, q-Growth: A Variational Approach

NASA Astrophysics Data System (ADS)

Bögelein, Verena; Duzaar, Frank; Marcellini, Paolo

2013-10-01

We consider the evolution problem associated with a convex integrand {f : {R}^{Nn}to [0,infty)} satisfying a non-standard p, q-growth assumption. To establish the existence of solutions we introduce the concept of variational solutions. In contrast to weak solutions, that is, mappings {u\\colon Ω_T to {R}^n} which solve partial_tu-div Df(Du)=0 weakly in {Ω_T}, variational solutions exist under a much weaker assumption on the gap q - p. Here, we prove the existence of variational solutions provided the integrand f is strictly convex and 2n/n+2 < p le q < p+1. These variational solutions turn out to be unique under certain mild additional assumptions on the data. Moreover, if the gap satisfies the natural stronger assumption 2le p le q < p+ minbig \\{1,4/n big \\}, we show that variational solutions are actually weak solutions. This means that solutions u admit the necessary higher integrability of the spatial derivative Du to satisfy the parabolic system in the weak sense, that is, we prove that uin L^q_locbig(0,T; W^{1,q}_loc(Ω,{R}^N)big).

The existence results and Tikhonov regularization method for generalized mixed variational inequalities in Banach spaces

NASA Astrophysics Data System (ADS)

Wang, Min

2017-06-01

This paper aims to establish the Tikhonov regularization method for generalized mixed variational inequalities in Banach spaces. For this purpose, we firstly prove a very general existence result for generalized mixed variational inequalities, provided that the mapping involved has the so-called mixed variational inequality property and satisfies a rather weak coercivity condition. Finally, we establish the Tikhonov regularization method for generalized mixed variational inequalities. Our findings extended the results for the generalized variational inequality problem (for short, GVIP( F, K)) in R^n spaces (He in Abstr Appl Anal, 2012) to the generalized mixed variational inequality problem (for short, GMVIP(F,φ , K)) in reflexive Banach spaces. On the other hand, we generalized the corresponding results for the generalized mixed variational inequality problem (for short, GMVIP(F,φ ,K)) in R^n spaces (Fu and He in J Sichuan Norm Univ (Nat Sci) 37:12-17, 2014) to reflexive Banach spaces.

Mapping Successional Stages in a Wet Tropical Forest Using Landsat ETM+ and Forest Inventory Data

NASA Technical Reports Server (NTRS)

Goncalves, Fabio G.; Yatskov, Mikhail; dos Santos, Joao Roberto; Treuhaft, Robert N.; Law, Beverly E.

2010-01-01

In this study, we test whether an existing classification technique based on the integration of Landsat ETM+ and forest inventory data enables detailed characterization of successional stages in a wet tropical forest site. The specific objectives were: (1) to map forest age classes across the La Selva Biological Station in Costa Rica; and (2) to quantify uncertainties in the proposed approach in relation to field data and existing vegetation maps. Although significant relationships between vegetation height entropy (a surrogate for forest age) and ETM+ data were detected, the classification scheme tested in this study was not suitable for characterizing spatial variation in age at La Selva, as evidenced by the error matrix and the low Kappa coefficient (12.9%). Factors affecting the performance of the classification at this particular study site include the smooth transition in vegetation structure between intermediate and advanced successional stages, and the low sensitivity of NDVI to variations in vertical structure at high biomass levels.

Estimation of time-dependent Hurst exponents with variational smoothing and application to forecasting foreign exchange rates

NASA Astrophysics Data System (ADS)

Garcin, Matthieu

2017-10-01

Hurst exponents depict the long memory of a time series. For human-dependent phenomena, as in finance, this feature may vary in the time. It justifies modelling dynamics by multifractional Brownian motions, which are consistent with time-dependent Hurst exponents. We improve the existing literature on estimating time-dependent Hurst exponents by proposing a smooth estimate obtained by variational calculus. This method is very general and not restricted to the sole Hurst framework. It is globally more accurate and easier than other existing non-parametric estimation techniques. Besides, in the field of Hurst exponents, it makes it possible to make forecasts based on the estimated multifractional Brownian motion. The application to high-frequency foreign exchange markets (GBP, CHF, SEK, USD, CAD, AUD, JPY, CNY and SGD, all against EUR) shows significantly good forecasts. When the Hurst exponent is higher than 0.5, what depicts a long-memory feature, the accuracy is higher.

Vanadium isotope heterogeneity of the early solar system

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Genetic regulation of the variation of circulating insulin-like growth factors and leptin in human pedigrees.

PubMed

Pantsulaia, Ia; Pantsulaia, I; Trofimov, Svetlana; Kobyliansky, Eugene; Livshits, Gregory

2005-07-01

Recent literature has shown that circulating levels of insulin-like growth factor I (IGF-I) and/or IGF binding proteins (IGF-BPs) may be of importance in the risk assessment of several chronic diseases including cancer, cardiovascular disease, diabetes mellitus and so on. The present study examined the extent of genetic and environmental influences on the populational variation of circulating IGF-I and IGF-BP-1 in apparently healthy and ethnically homogeneous white families. The plasma levels of each of the studied biochemical indices were determined by enzyme-linked immunoassay in 563 individuals aged 18 to 80 years. Quantitative genetic analysis showed that the IGF-I variation was appreciably attributable to genetic effects (47.1% +/- 9.0%), whereas for IGF-BP-1, only 23.3% +/- 7.8% of the interindividual variation was explained by genetic determinants. Common familial environment factors contributed significantly only to IGF-BP-1 variation (23.3% +/- 7.8%). In addition, we examined the covariations between these molecules and between them and IGF-BP-3 and leptin that were previously studied in the same sample. The analysis revealed that the pleiotropic genetic effects were significant for 2 pairs of traits, namely for IGF-I and IGF-BP-3, and for IGF-BP-1 and leptin. The bivariate heritability estimates were 0.21 +/- 0.04 and 0.15 +/- 0.05. The common environmental factors were consistently a significant source of correlation between all pairs (barring IGF-I and leptin) of the studied molecules; they were the sole predictors of correlation between IGF-I and IGF-BP-1, and between IGF-BP-1 and IGF-BP-3. Our results affirm the existence of specific and common genetic pathways that in combination determine a substantial proportion of the circulating variation of these molecules.

Variation in pediatric outpatient adenotonsillectomy costs in a multihospital network.

PubMed

Meier, Jeremy D; Zhang, Yingying; Greene, Tom H; Curtis, Jonathan L; Srivastava, Rajendu

2015-05-01

Identify hospital costs for same-day pediatric adenotonsillectomy (T&A) surgery, and evaluate surgeon, hospital, and patient factors influencing variation in costs, and compare relationship of costs to complications for T&A. Observational retrospective cohort study. A multihospital network's standardized activity-based accounting system was used to determine hospital costs per T&A from 1998 to 2012. Children 1 to 18 years old who underwent same-day T&A surgery were included. Subjects with additional procedures were excluded. Mixed effects analyses were performed to identify variation in mean costs due to surgeon, hospital, and patient factors. Surgeons' mean cost/case was related to subsequent complications, defined as any unplanned visit within 21 days in the healthcare system. The study cohort included 26,626 T&As performed by 66 surgeons at 18 hospitals. Mean cost per T&A was $1,355 ± $505. Mixed effects analysis using patient factors as fixed effects and surgeon and hospital as a random effect identified significant variation in mean costs per surgeon, with 95% of surgeons having a mean cost/case between 67% and 150% of the overall mean (range, $874-$2,232/case). Similar variability was found among hospitals, with 95% of the facilities having mean costs between 64% to 156% of the mean (range, $1,029-$2,385/case). Severity of illness and several other patient factors exhibited small but statistically significant associations with cost. Surgeons' mean cost/case was moderately associated with an increased complication rate. Significant variation in same-day pediatric T&A surgery costs exists among different surgeons and hospitals within a multihospital network. Reducing variation in costs while maintaining outcomes may improve healthcare value and eliminate waste. 4. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

Cost variation in a laparoscopic cholecystectomy and the association with outcomes across a single health system: implications for standardization and improved resource utilization.

PubMed

Brauer, David G; Hawkins, William G; Strasberg, Steven M; Brunt, L Michael; Jaques, David P; Mercurio, Nicholas R; Hall, Bruce L; Fields, Ryan C

2015-12-01

Payers and regulatory bodies are increasingly placing emphasis on cost containment, quality/outcome measurement and transparent reporting. Significant cost variation occurs in many operative procedures without a clear relationship with outcomes. Clear cost-benefit associations will be necessary to justify expenditures in the era of bundled payment structures. All laparoscopic cholecystectomies (LCCKs) performed within a single health system over a 1-year period were analysed for operating room (OR) supply cost. The cost was correlated with American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) outcomes. From July 2013 to June 2014, 2178 LCCKs were performed by 55 surgeons at seven hospitals. The median case OR supply cost was $513 ± 156. There was variation in cost between individual surgeons and within an individual surgeon's practice. There was no correlation between cost and ACS NSQIP outcomes. The majority of cost variation was explained by selection of trocar and clip applier constructs. Significant case OR cost variation is present in LCCK across a single health system, and there is no clear association between increased cost and NSQIP outcomes. Placed within the larger context of overall cost, the opportunity exists for improved resource utilization with no obvious risk for a reduction in the quality of care. © 2015 International Hepato-Pancreato-Biliary Association.

Cost variation in a laparoscopic cholecystectomy and the association with outcomes across a single health system: implications for standardization and improved resource utilization

PubMed Central

Brauer, David G; Hawkins, William G; Strasberg, Steven M; Brunt, L Michael; Jaques, David P; Mercurio, Nicholas R; Hall, Bruce L; Fields, Ryan C

2015-01-01

Background Payers and regulatory bodies are increasingly placing emphasis on cost containment, quality/outcome measurement and transparent reporting. Significant cost variation occurs in many operative procedures without a clear relationship with outcomes. Clear cost-benefit associations will be necessary to justify expenditures in the era of bundled payment structures. Methods All laparoscopic cholecystectomies (LCCKs) performed within a single health system over a 1-year period were analysed for operating room (OR) supply cost. The cost was correlated with American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) outcomes. Results From July 2013 to June 2014, 2178 LCCKs were performed by 55 surgeons at seven hospitals. The median case OR supply cost was $513 ± 156. There was variation in cost between individual surgeons and within an individual surgeon's practice. There was no correlation between cost and ACS NSQIP outcomes. The majority of cost variation was explained by selection of trocar and clip applier constructs. Conclusions Significant case OR cost variation is present in LCCK across a single health system, and there is no clear association between increased cost and NSQIP outcomes. Placed within the larger context of overall cost, the opportunity exists for improved resource utilization with no obvious risk for a reduction in the quality of care. PMID:26345351

The Roles of Standing Genetic Variation and Evolutionary History in Determining the Evolvability of Anti-Predator Strategies

PubMed Central

Dworkin, Ian; Wagner, Aaron P.

2014-01-01

Standing genetic variation and the historical environment in which that variation arises (evolutionary history) are both potentially significant determinants of a population's capacity for evolutionary response to a changing environment. Using the open-ended digital evolution software Avida, we evaluated the relative importance of these two factors in influencing evolutionary trajectories in the face of sudden environmental change. We examined how historical exposure to predation pressures, different levels of genetic variation, and combinations of the two, affected the evolvability of anti-predator strategies and competitive abilities in the presence or absence of threats from new, invasive predator populations. We show that while standing genetic variation plays some role in determining evolutionary responses, evolutionary history has the greater influence on a population's capacity to evolve anti-predator traits, i.e. traits effective against novel predators. This adaptability likely reflects the relative ease of repurposing existing, relevant genes and traits, and the broader potential value of the generation and maintenance of adaptively flexible traits in evolving populations. PMID:24955847

Memristive crypto primitive for building highly secure physical unclonable functions

NASA Astrophysics Data System (ADS)

Gao, Yansong; Ranasinghe, Damith C.; Al-Sarawi, Said F.; Kavehei, Omid; Abbott, Derek

2015-08-01

Physical unclonable functions (PUFs) exploit the intrinsic complexity and irreproducibility of physical systems to generate secret information. The advantage is that PUFs have the potential to provide fundamentally higher security than traditional cryptographic methods by preventing the cloning of devices and the extraction of secret keys. Most PUF designs focus on exploiting process variations in Complementary Metal Oxide Semiconductor (CMOS) technology. In recent years, progress in nanoelectronic devices such as memristors has demonstrated the prevalence of process variations in scaling electronics down to the nano region. In this paper, we exploit the extremely large information density available in nanocrossbar architectures and the significant resistance variations of memristors to develop an on-chip memristive device based strong PUF (mrSPUF). Our novel architecture demonstrates desirable characteristics of PUFs, including uniqueness, reliability, and large number of challenge-response pairs (CRPs) and desirable characteristics of strong PUFs. More significantly, in contrast to most existing PUFs, our PUF can act as a reconfigurable PUF (rPUF) without additional hardware and is of benefit to applications needing revocation or update of secure key information.

Memristive crypto primitive for building highly secure physical unclonable functions.

PubMed

Gao, Yansong; Ranasinghe, Damith C; Al-Sarawi, Said F; Kavehei, Omid; Abbott, Derek

2015-08-04

Physical unclonable functions (PUFs) exploit the intrinsic complexity and irreproducibility of physical systems to generate secret information. The advantage is that PUFs have the potential to provide fundamentally higher security than traditional cryptographic methods by preventing the cloning of devices and the extraction of secret keys. Most PUF designs focus on exploiting process variations in Complementary Metal Oxide Semiconductor (CMOS) technology. In recent years, progress in nanoelectronic devices such as memristors has demonstrated the prevalence of process variations in scaling electronics down to the nano region. In this paper, we exploit the extremely large information density available in nanocrossbar architectures and the significant resistance variations of memristors to develop an on-chip memristive device based strong PUF (mrSPUF). Our novel architecture demonstrates desirable characteristics of PUFs, including uniqueness, reliability, and large number of challenge-response pairs (CRPs) and desirable characteristics of strong PUFs. More significantly, in contrast to most existing PUFs, our PUF can act as a reconfigurable PUF (rPUF) without additional hardware and is of benefit to applications needing revocation or update of secure key information.

Memristive crypto primitive for building highly secure physical unclonable functions

PubMed Central

Gao, Yansong; Ranasinghe, Damith C.; Al-Sarawi, Said F.; Kavehei, Omid; Abbott, Derek

2015-01-01

Physical unclonable functions (PUFs) exploit the intrinsic complexity and irreproducibility of physical systems to generate secret information. The advantage is that PUFs have the potential to provide fundamentally higher security than traditional cryptographic methods by preventing the cloning of devices and the extraction of secret keys. Most PUF designs focus on exploiting process variations in Complementary Metal Oxide Semiconductor (CMOS) technology. In recent years, progress in nanoelectronic devices such as memristors has demonstrated the prevalence of process variations in scaling electronics down to the nano region. In this paper, we exploit the extremely large information density available in nanocrossbar architectures and the significant resistance variations of memristors to develop an on-chip memristive device based strong PUF (mrSPUF). Our novel architecture demonstrates desirable characteristics of PUFs, including uniqueness, reliability, and large number of challenge-response pairs (CRPs) and desirable characteristics of strong PUFs. More significantly, in contrast to most existing PUFs, our PUF can act as a reconfigurable PUF (rPUF) without additional hardware and is of benefit to applications needing revocation or update of secure key information. PMID:26239669

On a strong solution of the non-stationary Navier-Stokes equations under slip or leak boundary conditions of friction type

NASA Astrophysics Data System (ADS)

Kashiwabara, Takahito

Strong solutions of the non-stationary Navier-Stokes equations under non-linearized slip or leak boundary conditions are investigated. We show that the problems are formulated by a variational inequality of parabolic type, to which uniqueness is established. Using Galerkin's method and deriving a priori estimates, we prove global and local existence for 2D and 3D slip problems respectively. For leak problems, under no-leak assumption at t=0 we prove local existence in 2D and 3D cases. Compatibility conditions for initial states play a significant role in the estimates.

Seasonal variation in penicillin use in Mexico and Brazil: analysis of the impact of over-the-counter restrictions.

PubMed

Santa-Ana-Tellez, Yared; Mantel-Teeuwisse, Aukje K; Leufkens, Hubert G M; Wirtz, Veronika J

2015-01-01

During 2010, Mexico and Brazil implemented policies to enforce existing laws of restricting over-the-counter sales of antibiotics. We determined if the enforcement led to more appropriate antibiotic use by measuring changes in seasonal variation of penicillin use. We used retail quarterly sales data in defined daily doses per 1,000 inhabitant-days (DDD/TID) from IMS Health from the private sector in Mexico and Brazil from the first quarter of 2007 to the first quarter of 2013. This database contains information on volume of antibiotics sold in retail pharmacies using information from wholesalers. We used interrupted time-series models controlling for external factors with the use of antihypertensives with interaction terms to assess changes in trend, level, and variation in use between quarters for total penicillin use and by active substance. The most used penicillin was amoxicillin, followed by amoxicillin-clavulanic acid and ampicillin (minimal use in Brazil). Before the restrictions, the seasonal variation in penicillin use was 1.1 DDD/TID in Mexico and 0.8 DDD/TID in Brazil. In Mexico, we estimated a significant decrease in the seasonal variation of 0.4 DDD/TID after the restriction, mainly due to changes in seasonal variation of amoxicillin and ampicillin. In Brazil, the seasonal variation did not change significantly, overall and in the breakdown by individual active substances. For Mexico, inappropriate penicillin use may have diminished after the restrictions were enforced. For Brazil, increasing use and no change in seasonal variation suggest that further efforts are needed to reduce inappropriate penicillin use. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

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

PubMed

Omvik, P

1984-01-01

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

Individual variation in social aggression and the probability of inheritance: theory and a field test.

PubMed

Cant, Michael A; Llop, Justine B; Field, Jeremy

2006-06-01

Recent theory suggests that much of the wide variation in individual behavior that exists within cooperative animal societies can be explained by variation in the future direct component of fitness, or the probability of inheritance. Here we develop two models to explore the effect of variation in future fitness on social aggression. The models predict that rates of aggression will be highest toward the front of the queue to inherit and will be higher in larger, more productive groups. A third prediction is that, in seasonal animals, aggression will increase as the time available to inherit the breeding position runs out. We tested these predictions using a model social species, the paper wasp Polistes dominulus. We found that rates of both aggressive "displays" (aimed at individuals of lower rank) and aggressive "tests" (aimed at individuals of higher rank) decreased down the hierarchy, as predicted by our models. The only other significant factor affecting aggression rates was date, with more aggression observed later in the season, also as predicted. Variation in future fitness due to inheritance rank is the hidden factor accounting for much of the variation in aggressiveness among apparently equivalent individuals in this species.

Qualitative variation of photolabelled benzodiazepine receptors in different species.

PubMed

Hebebrand, J; Friedl, W; Lentes, K U; Propping, P

1986-01-01

In order to examine whether species differences of benzodiazepine receptor subunits exist, we compared the fluorographic pattern of photoaffinity labelled subunits after SDS-PAGE in five species: fish, frog, chicken, mouse and calf. Each species showed a distinct pattern of specifically labelled proteins. We conclude that species variation of benzodiazepine receptor does indeed exist.

Treatment Recommendations for Single-Unit Crowns: Findings from The National Dental Practice-Based Research Network

PubMed Central

McCracken, Michael S.; Louis, David R.; Litaker, Mark S.; Minyé, Helena M.; Mungia, Rahma; Gordan, Valeria V.; Marshall, Don G.; Gilbert, Gregg H.

2016-01-01

Background Objectives were to: (1) quantify practitioner variation in likelihood to recommend a crown; and (2) test whether certain dentist, practice, and clinical factors are significantly associated with this likelihood. Methods Dentists in the National Dental Practice-Based Research Network completed a questionnaire about indications for single-unit crowns. In four clinical scenarios, practitioners ranked their likelihood of recommending a single-unit crown. These responses were used to calculate a dentist-specific “Crown Factor” (CF; range 0–12). A higher score implies a higher likelihood to recommend a crown. Certain characteristics were tested for statistically significant associations with the CF. Results 1,777 of 2,132 eligible dentists responded (83%). Practitioners were most likely to recommend crowns for teeth that were fractured, cracked, endodontically-treated, or had a broken restoration. Practitioners overwhelmingly recommended crowns for posterior teeth treated endodontically (94%). Practice owners, Southwest practitioners, and practitioners with a balanced work load were more likely to recommend crowns, as were practitioners who use optical scanners for digital impressions. Conclusions There is substantial variation in the likelihood of recommending a crown. While consensus exists in some areas (posterior endodontic treatment), variation dominates in others (size of an existing restoration). Recommendations varied by type of practice, network region, practice busyness, patient insurance status, and use of optical scanners. Practical Implications Recommendations for crowns may be influenced by factors unrelated to tooth and patient variables. A concern for tooth fracture -- whether from endodontic treatment, fractured teeth, or large restorations -- prompted many clinicians to recommend crowns. PMID:27492046

Patterns of genetic differentiation and conservation of the slabside pearlymussel, Lexingtonia dolabelloides (Lea, 1840) in the Tennessee River drainage

USGS Publications Warehouse

Grobler, P.J.; Jones, J.W.; Johnson, N.A.; Beaty, B.; Struthers, J.; Neves, R.J.; Hallerman, E.M.

2006-01-01

The restoration and recovery of imperiled mussel species will require the re-establishment of populations into historically occupied habitats. The possible existence of genetic differentiation among populations should be considered before inter-basin transfers are made. Eighty individuals of the federal candidate species Lexingtonia dolabelloides were sampled from populations in the North Fork Holston, Middle Fork Holston, Clinch, Paint Rock and Duck rivers of the Tennessee River basin in the southeastern United States. We sequenced 603 base-pairs of a mitochondrial DNA gene (ND-1) and 512 base-pairs of a nuclear DNA gene (ITS-1). Analyses of molecular variation (AMOVA) values for both genes indicated that the majority of variation in L. dolabelloides resided within populations (82.9-88.3%), with 11.7-17.1% of variation among populations. Haplotype frequencies differed significantly among populations for both genes sequenced. Clustering of haplotypes in minimum-spanning networks did not conform stringently to population boundaries, reflecting high within-population and low between-population variability. Maximum parsimony analysis did not identify any population as a monophyletic lineage. A Mantel test showed no significant correlation between geographical stream distance and genetic distance, thus not supporting a pattern of isolation-by-distance. Overall, results provided support to manage fragmented populations of L. dolabelloides in the Tennessee River drainage as two management units (MUs), but did not provide evidence for the existence of ESUs following published molecular criteria. ?? The Author 2005. Published by Oxford University Studies on behalf of The Malacological Society of London, all rights reserved.

A preliminary investigation into the genetic variation and population structure of Taenia hydatigena from Sardinia, Italy.

PubMed

Boufana, Belgees; Scala, Antonio; Lahmar, Samia; Pointing, Steve; Craig, Philip S; Dessì, Giorgia; Zidda, Antonella; Pipia, Anna Paola; Varcasia, Antonio

2015-11-30

Cysticercosis caused by the metacestode stage of Taenia hydatigena is endemic in Sardinia. Information on the genetic variation of this parasite is important for epidemiological studies and implementation of control programs. Using two mitochondrial genes, the cytochrome c oxidase subunit 1 (cox1) and the NADH dehydrogenase subunit 1 (ND1) we investigated the genetic variation and population structure of Cysticercus tenuicollis from Sardinian intermediate hosts and compared it to that from other hosts from various geographical regions. The parsimony cox1 network analysis indicated the existence of a common lineage for T. hydatigena and the overall diversity and neutrality indices indicated demographic expansion. Using the cox1 sequences, low pairwise fixation index (Fst) values were recorded for Sardinian, Iranian and Palestinian sheep C. tenuicollis which suggested the absence of genetic differentiation. Using the ND1 sequences, C. tenuicollis from Sardinian sheep appeared to be differentiated from those of goat and pig origin. In addition, goat C. tenuicollis were genetically different from adult T. hydatigena as indicated by the statistically significant Fst value. Our results are consistent with biochemical and morphological studies that suggest the existence of variants of T. hydatigena. Copyright © 2015 Elsevier B.V. All rights reserved.

Heritable variation in host tolerance and resistance inferred from a wild host-parasite system.

PubMed

Mazé-Guilmo, Elise; Loot, Géraldine; Páez, David J; Lefèvre, Thierry; Blanchet, Simon

2014-03-22

Hosts have evolved two distinct defence strategies against parasites: resistance (which prevents infection or limit parasite growth) and tolerance (which alleviates the fitness consequences of infection). However, heritable variation in resistance and tolerance and the genetic correlation between these two traits have rarely been characterized in wild host populations. Here, we estimate these parameters for both traits in Leuciscus burdigalensis, a freshwater fish parasitized by Tracheliastes polycolpus. We used a genetic database to construct a full-sib pedigree in a wild L. burdigalensis population. We then used univariate animal models to estimate inclusive heritability (i.e. all forms of genetic and non-genetic inheritance) in resistance and tolerance. Finally, we assessed the genetic correlation between these two traits using a bivariate animal model. We found significant heritability for resistance (H = 17.6%; 95% CI: 7.2-32.2%) and tolerance (H = 18.8%; 95% CI: 4.4-36.1%), whereas we found no evidence for the existence of a genetic correlation between these traits. Furthermore, we confirm that resistance and tolerance are strongly affected by environmental effects. Our results demonstrate that (i) heritable variation exists for parasite resistance and tolerance in wild host populations, and (ii) these traits can evolve independently in populations.

Sinonasal anatomical variations: their relationship with chronic rhinosinusitis and effect on the severity of disease-a computerized tomography assisted anatomical and clinical study.

PubMed

Kaygusuz, Ahmet; Haksever, Mehmet; Akduman, Davut; Aslan, Sündüs; Sayar, Zeynep

2014-09-01

The anatomy of the sinonasal area has a very wide rage of anatomical variations. The significance of these anatomical variations in pathogenesis of rhinosinusitis, which is the commonest disease in the region, is still unclear. The aims of the study were to compare the rate of sinonasal anatomical variations with development and severity of chronic rhinosinusitis patients. CT scan of paranasal sinuses images of 99 individuals were retrospectively reviewed. 65 cases of chronic rhinosinusitis (study group) who had undergone endoscopic sinus surgery were compared with 34 cases without chronic rhinosinusitis (control group). Also in study group Lund-Mackay score of the sinus disease were calculated and compared to the rate of related anatomical variations. There were 74 (74.7 %) males and 25 (25.2 %) females with ages ranging from 13 to 70 years (mean 32.2 years). The anatomical variations recorded were: Septal deviation 47 (72.3) in study and 25 (73.5 %) in control group, concha bullosa 27 (41.5 %) in study and 18 (52.9 %) in control group, overpneumatized ethmoid bulla 17 (26.1 %) in study and 14 (41.1 %) in control group, pneumatized uncinate 3 (4.6 %) in study and 3 (8.8 %) in control group, agger nasi 42 (64.6 %) in study and 19 (55.8 %) in control group, paradoxical middle turbinates 9 (13.8 %) in study and 4 (11.7 %) in control group, Onodi cell 6 (9.2 %) in study and 2 (5.8 %) in control group, Haller's cells (infraorbital ethmoid cell) 9 (13.8 %) in study and 7 (20.5 %) in control group. None of these results were statistically significant between study and control group (p > 0.05). Lund-Mackay score (which was assumed to show the severity of the disease) of the maxillary, ethmoid and frontal sinus were calculated and compared to rate of septal deviation, concha bullosa, agger nasi cells. No significant correlation was conducted (p > 0.05). The results of study showed no statistically significant correlation between sinonasal anatomical variations and pathologies of the paranasal sinus. Also these anatomical variations did not increase the severity of pre-existing sinusitis significantly. This is a retrospective cohort study (2b).

CNV-TV: a robust method to discover copy number variation from short sequencing reads.

PubMed

Duan, Junbo; Zhang, Ji-Gang; Deng, Hong-Wen; Wang, Yu-Ping

2013-05-02

Copy number variation (CNV) is an important structural variation (SV) in human genome. Various studies have shown that CNVs are associated with complex diseases. Traditional CNV detection methods such as fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (aCGH) suffer from low resolution. The next generation sequencing (NGS) technique promises a higher resolution detection of CNVs and several methods were recently proposed for realizing such a promise. However, the performances of these methods are not robust under some conditions, e.g., some of them may fail to detect CNVs of short sizes. There has been a strong demand for reliable detection of CNVs from high resolution NGS data. A novel and robust method to detect CNV from short sequencing reads is proposed in this study. The detection of CNV is modeled as a change-point detection from the read depth (RD) signal derived from the NGS, which is fitted with a total variation (TV) penalized least squares model. The performance (e.g., sensitivity and specificity) of the proposed approach are evaluated by comparison with several recently published methods on both simulated and real data from the 1000 Genomes Project. The experimental results showed that both the true positive rate and false positive rate of the proposed detection method do not change significantly for CNVs with different copy numbers and lengthes, when compared with several existing methods. Therefore, our proposed approach results in a more reliable detection of CNVs than the existing methods.

Analysis of MAGSAT and surface data of the Indian region

NASA Technical Reports Server (NTRS)

Agarwal, G. C. (Principal Investigator)

1983-01-01

Techniques and significant results of an analysis of MAGSAT and surface data of the Indian region are described. Specific investigative tasks included: (1) use of the multilevel data at different altitudes to develop a model for variation of magnetic anomaly with altitude; (2) development of the regional model for the description of main geomagnetic field for the Indian sub-continent using MAGSAT and observatory data; (3) development of regional mathematical model of secular variations over the Indian sub-continent; and (4) downward continuation of the anomaly field obtained from MAGSAT and its combination with the existing observatory data to produce a regional anomaly map for elucidating tectonic features of the Indian sub-continent.

Metallogenic specialization of supercontinent cycles: A case study of silver deposits

NASA Astrophysics Data System (ADS)

Tkachev, A. V.; Rundqvist, D. V.; Vishnevskaya, N. A.

2017-07-01

The distribution of integrated resources of large and superlarge mineral deposits (LSLDs) of silver, where the main part of industrially recoverable silver reserves is concentrated, is compared with the existing model of supercontinent cyclicity over the geological history of the Earth. It is found that each supercontinent cycle (Kenoran, Columbian, Rodinian, Pangean, and Amasian) is particularly expressed in the silver metallogeny. The significant intercycle variations in the numbers of LSLDs, diversity of types of these deposits, accumulated resources, mean tenors of silver in ores, and some other numerically expressible characteristics are revealed. These variations correlate with a number of geohistorical changes in the conditions under which endogenous and exogenous geological processes run.

ParseCNV integrative copy number variation association software with quality tracking

PubMed Central

Glessner, Joseph T.; Li, Jin; Hakonarson, Hakon

2013-01-01

A number of copy number variation (CNV) calling algorithms exist; however, comprehensive software tools for CNV association studies are lacking. We describe ParseCNV, unique software that takes CNV calls and creates probe-based statistics for CNV occurrence in both case–control design and in family based studies addressing both de novo and inheritance events, which are then summarized based on CNV regions (CNVRs). CNVRs are defined in a dynamic manner to allow for a complex CNV overlap while maintaining precise association region. Using this approach, we avoid failure to converge and non-monotonic curve fitting weaknesses of programs, such as CNVtools and CNVassoc, and although Plink is easy to use, it only provides combined CNV state probe-based statistics, not state-specific CNVRs. Existing CNV association methods do not provide any quality tracking information to filter confident associations, a key issue which is fully addressed by ParseCNV. In addition, uncertainty in CNV calls underlying CNV associations is evaluated to verify significant results, including CNV overlap profiles, genomic context, number of probes supporting the CNV and single-probe intensities. When optimal quality control parameters are followed using ParseCNV, 90% of CNVs validate by polymerase chain reaction, an often problematic stage because of inadequate significant association review. ParseCNV is freely available at http://parsecnv.sourceforge.net. PMID:23293001

ParseCNV integrative copy number variation association software with quality tracking.

PubMed

Glessner, Joseph T; Li, Jin; Hakonarson, Hakon

2013-03-01

A number of copy number variation (CNV) calling algorithms exist; however, comprehensive software tools for CNV association studies are lacking. We describe ParseCNV, unique software that takes CNV calls and creates probe-based statistics for CNV occurrence in both case-control design and in family based studies addressing both de novo and inheritance events, which are then summarized based on CNV regions (CNVRs). CNVRs are defined in a dynamic manner to allow for a complex CNV overlap while maintaining precise association region. Using this approach, we avoid failure to converge and non-monotonic curve fitting weaknesses of programs, such as CNVtools and CNVassoc, and although Plink is easy to use, it only provides combined CNV state probe-based statistics, not state-specific CNVRs. Existing CNV association methods do not provide any quality tracking information to filter confident associations, a key issue which is fully addressed by ParseCNV. In addition, uncertainty in CNV calls underlying CNV associations is evaluated to verify significant results, including CNV overlap profiles, genomic context, number of probes supporting the CNV and single-probe intensities. When optimal quality control parameters are followed using ParseCNV, 90% of CNVs validate by polymerase chain reaction, an often problematic stage because of inadequate significant association review. ParseCNV is freely available at http://parsecnv.sourceforge.net.

Absolute photometric calibration of IRAC: lessons learned using nine years of flight data

NASA Astrophysics Data System (ADS)

Carey, S.; Ingalls, J.; Hora, J.; Surace, J.; Glaccum, W.; Lowrance, P.; Krick, J.; Cole, D.; Laine, S.; Engelke, C.; Price, S.; Bohlin, R.; Gordon, K.

2012-09-01

Significant improvements in our understanding of various photometric effects have occurred in the more than nine years of flight operations of the Infrared Array Camera aboard the Spitzer Space Telescope. With the accumulation of calibration data, photometric variations that are intrinsic to the instrument can now be mapped with high fidelity. Using all existing data on calibration stars, the array location-dependent photometric correction (the variation of flux with position on the array) and the correction for intra-pixel sensitivity variation (pixel-phase) have been modeled simultaneously. Examination of the warm mission data enabled the characterization of the underlying form of the pixelphase variation in cryogenic data. In addition to the accumulation of calibration data, significant improvements in the calibration of the truth spectra of the calibrators has taken place. Using the work of Engelke et al. (2006), the KIII calibrators have no offset as compared to the AV calibrators, providing a second pillar of the calibration scheme. The current cryogenic calibration is better than 3% in an absolute sense, with most of the uncertainty still in the knowledge of the true flux densities of the primary calibrators. We present the final state of the cryogenic IRAC calibration and a comparison of the IRAC calibration to an independent calibration methodology using the HST primary calibrators.

A Variational Reduction and the Existence of a Fully Localised Solitary Wave for the Three-Dimensional Water-Wave Problem with Weak Surface Tension

NASA Astrophysics Data System (ADS)

Buffoni, Boris; Groves, Mark D.; Wahlén, Erik

2017-12-01

Fully localised solitary waves are travelling-wave solutions of the three- dimensional gravity-capillary water wave problem which decay to zero in every horizontal spatial direction. Their existence has been predicted on the basis of numerical simulations and model equations (in which context they are usually referred to as `lumps'), and a mathematically rigorous existence theory for strong surface tension (Bond number {β} greater than {1/3} ) has recently been given. In this article we present an existence theory for the physically more realistic case {0 < β < 1/3} . A classical variational principle for fully localised solitary waves is reduced to a locally equivalent variational principle featuring a perturbation of the functional associated with the Davey-Stewartson equation. A nontrivial critical point of the reduced functional is found by minimising it over its natural constraint set.

A Variational Reduction and the Existence of a Fully Localised Solitary Wave for the Three-Dimensional Water-Wave Problem with Weak Surface Tension

NASA Astrophysics Data System (ADS)

Buffoni, Boris; Groves, Mark D.; Wahlén, Erik

2018-06-01

Fully localised solitary waves are travelling-wave solutions of the three- dimensional gravity-capillary water wave problem which decay to zero in every horizontal spatial direction. Their existence has been predicted on the basis of numerical simulations and model equations (in which context they are usually referred to as `lumps'), and a mathematically rigorous existence theory for strong surface tension (Bond number {β} greater than {1/3}) has recently been given. In this article we present an existence theory for the physically more realistic case {0 < β < 1/3}. A classical variational principle for fully localised solitary waves is reduced to a locally equivalent variational principle featuring a perturbation of the functional associated with the Davey-Stewartson equation. A nontrivial critical point of the reduced functional is found by minimising it over its natural constraint set.

Face recognition via edge-based Gabor feature representation for plastic surgery-altered images

NASA Astrophysics Data System (ADS)

Chude-Olisah, Chollette C.; Sulong, Ghazali; Chude-Okonkwo, Uche A. K.; Hashim, Siti Z. M.

2014-12-01

Plastic surgery procedures on the face introduce skin texture variations between images of the same person (intra-subject), thereby making the task of face recognition more difficult than in normal scenario. Usually, in contemporary face recognition systems, the original gray-level face image is used as input to the Gabor descriptor, which translates to encoding some texture properties of the face image. The texture-encoding process significantly degrades the performance of such systems in the case of plastic surgery due to the presence of surgically induced intra-subject variations. Based on the proposition that the shape of significant facial components such as eyes, nose, eyebrow, and mouth remains unchanged after plastic surgery, this paper employs an edge-based Gabor feature representation approach for the recognition of surgically altered face images. We use the edge information, which is dependent on the shapes of the significant facial components, to address the plastic surgery-induced texture variation problems. To ensure that the significant facial components represent useful edge information with little or no false edges, a simple illumination normalization technique is proposed for preprocessing. Gabor wavelet is applied to the edge image to accentuate on the uniqueness of the significant facial components for discriminating among different subjects. The performance of the proposed method is evaluated on the Georgia Tech (GT) and the Labeled Faces in the Wild (LFW) databases with illumination and expression problems, and the plastic surgery database with texture changes. Results show that the proposed edge-based Gabor feature representation approach is robust against plastic surgery-induced face variations amidst expression and illumination problems and outperforms the existing plastic surgery face recognition methods reported in the literature.

The Relationship of Red and Photographic Infrared Spectral Data to Grain Yield Variation Within a Winter Wheat Field

NASA Technical Reports Server (NTRS)

Tucker, C. J.; Holben, B. N.; Elgin, J. H., Jr.; Mcmurtrey, J. E., III

1979-01-01

Two band hand-held radiometer data from a winter wheat field, collected on 21 dates during the spring growing season, were correlated within field final grain yield. Significant linear relationships were found between various combinations of the red and photographic infrared radiance data collected and the grain yield. The spectral data explained approximately 64 percent of the within field grain yield variation. This variation in grain yield could not be explained using meteorological data as these were similar for all areas of the wheat field. Most importantly, data collected early in the spring were highly correlated with grain yield, a five week time window existed from stem elongation through antheses in which the spectral data were most highly correlated with grain yield, and manifestations of wheat canopy water stress were readily apparent in the spectral data.

Diode‐based transmission detector for IMRT delivery monitoring: a validation study

PubMed Central

Li, Taoran; Wu, Q. Jackie; Matzen, Thomas; Yin, Fang‐Fang

2016-01-01

The purpose of this work was to evaluate the potential of a new transmission detector for real‐time quality assurance of dynamic‐MLC‐based radiotherapy. The accuracy of detecting dose variation and static/dynamic MLC position deviations was measured, as well as the impact of the device on the radiation field (surface dose, transmission). Measured dose variations agreed with the known variations within 0.3%. The measurement of static and dynamic MLC position deviations matched the known deviations with high accuracy (0.7–1.2 mm). The absorption of the device was minimal (∼ 1%). The increased surface dose was small (1%–9%) but, when added to existing collimator scatter effects could become significant at large field sizes (≥30×30 cm2). Overall the accuracy and speed of the device show good potential for real‐time quality assurance. PACS number(s): 87.55.Qr PMID:27685115

The evolution of sex differences in mate searching when females benefit: new theory and a comparative test.

PubMed

McCartney, J; Kokko, H; Heller, K-G; Gwynne, D T

2012-03-22

Sexual selection is thought to have led to searching as a profitable, but risky way of males obtaining mates. While there is great variation in which sex searches, previous theory has not considered search evolution when both males and females benefit from multiple mating. We present new theory and link it with data to bridge this gap. Two different search protocols exist between species in the bush-cricket genus Poecilimon (Orthoptera): females search for calling males, or males search for calling females. Poecilimon males also transfer a costly nuptial food gift to their mates during mating. We relate variations in searching protocols to variation in nuptial gift size among 32 Poecilimon taxa. As predicted, taxa where females search produce significantly larger nuptial gifts than those where males search. Our model and results show that search roles can reverse when multiple mating brings about sufficiently strong material benefits to females.

Magnetic activity of red secondaries: clues from the outburst cycle variations of dwarf novae

NASA Astrophysics Data System (ADS)

Chinarova, L. L.

Photometric variations of 6 dwarf novae stars are studied based on the photographic observations from the Odessa, Moscow and Sonneberg plate collections and published visual monitoring data from the AFOEV database (Schweitzer E.: 1993, Bull. AFOEV, 64, 14). The moments of maxima are determined by using the "running parabola" fit (Andronov I.L., 1990, Kinematika Fizika Nebesn. Tel., v.6,,N 6, 87) with automatically determined filter half-width (Andronov I.L., 1997, As.Ap. Suppl., in press). All investigated stars exhibit significant changes not only from cycle-to-cycle, but from season-to-season as well. Secondary decade-scale cycles of smooth variations (Bianchini A., 1990, AJ 99, 1941) and abrupt switchings (Andronov I.L., Shakun L.I., 1990, ASS 169, 237) were interpreted by a solar-type activity of the red dwarf secondary in a binary system and may argue for existence of two different subgroups of the dwarf novae.

How the macroeconomic context impacts on attitudes to immigration: Evidence from within-country variation.

PubMed

Ruist, Joakim

2016-11-01

This study investigates the effects of the macroeconomic context on attitudes to immigration. Earlier studies do in some cases not provide significant empirical support for the existence of important such effects. In this article it is argued that this lack of consistent evidence is mainly due to the cross-national setup of these studies being vulnerable to estimation bias caused by country-specific factors. The present study instead analyzes attitude variation within countries over time. The results provide firm empirical support in favor of macroeconomic variation importantly affecting attitudes to immigration. As an illustration, the estimates indicate that the number of individuals in the average European country in 2012 who were against all immigration from poorer countries outside Europe was 40% higher than it would have been if macroeconomic conditions in that year had been as good as they were in 2006. Copyright © 2016 Elsevier Inc. All rights reserved.

Patient Handoffs between Emergency Department and Inpatient Physicians: A Qualitative Study to Inform Standardization of Practice and Organization Theory

ERIC Educational Resources Information Center

Hilligoss, Phillip Brian

2011-01-01

This dissertation is motivated by two problems. First, existing literature characterizes patient handoff as an information transfer activity in which safety and quality are compromised by practice variation. This has prompted a movement to standardize practice. However, existing research has not closely examined how practice variations may be…

An Application of Variational Theory to an Integrated Walrasian Model of Exchange, Consumption and Production

NASA Astrophysics Data System (ADS)

Donato, M. B.; Milasi, M.; Vitanza, C.

2010-09-01

An existence result of a Walrasian equilibrium for an integrated model of exchange, consumption and production is obtained. The equilibrium model is characterized in terms of a suitable generalized quasi-variational inequality; so the existence result comes from an original technique which takes into account tools of convex and set-valued analysis.

Geographical variation in the periodicity of gypsy moth outbreaks

Treesearch

Derek M. Johnson; Andrew M. Liebhold; Ottar N. Bj& #248rnstad

2006-01-01

The existence of periodic oscillations in populations of forest Lepidoptera is well known. While information exists on how the periods of oscillations vary among different species, there is little prior evidence of variation in periodicity within the range of a single Lepidopteran species. The exotic gypsy moth is an introduced foliage-feeding insect in North America....

Genotype-Specific Variation in the Structure of Root Fungal Communities Is Related to Chickpea Plant Productivity

PubMed Central

Hamel, Chantal; Gan, Yantai; Tar'an, Bunyamin; Knight, Joan Diane

2015-01-01

Increasing evidence supports the existence of variations in the association of plant roots with symbiotic fungi that can improve plant growth and inhibit pathogens. However, it is unclear whether intraspecific variations in the symbiosis exist among plant cultivars and if they can be used to improve crop productivity. In this study, we determined genotype-specific variations in the association of chickpea roots with soil fungal communities and evaluated the effect of root mycota on crop productivity. A 2-year field experiment was conducted in southwestern Saskatchewan, the central zone of the chickpea growing region of the Canadian prairie. The effects of 13 cultivars of chickpea, comprising a wide range of phenotypes and genotypes, were tested on the structure of root-associated fungal communities based on internal transcribed spacer (ITS) and 18S rRNA gene markers using 454 amplicon pyrosequencing. Chickpea cultivar significantly influenced the structure of the root fungal community. The magnitude of the effect varied with the genotypes evaluated, and effects were consistent across years. For example, the roots of CDC Corrine, CDC Cory, and CDC Anna hosted the highest fungal diversity and CDC Alma and CDC Xena the lowest. Fusarium sp. was dominant in chickpea roots but was less abundant in CDC Corrine than the other cultivars. A bioassay showed that certain of these fungal taxa, including Fusarium species, can reduce the productivity of chickpea, whereas Trichoderma harzianum can increase chickpea productivity. The large variation in the profile of chickpea root mycota, which included growth-promoting and -inhibiting species, supports the possibility of improving the productivity of chickpea by improving its root mycota in chickpea genetic improvement programs using traditional breeding techniques. PMID:25616789

Variation among cleft centres in the use of secondary surgery for children with cleft palate: a retrospective cohort study

PubMed Central

Sitzman, Thomas J; Hossain, Monir; Carle, Adam C; Heaton, Pamela C; Britto, Maria T

2017-01-01

Objectives To test whether cleft centres vary in their use of secondary cleft palate surgery, also known as revision palate surgery, and if so to identify modifiable hospital factors and surgeon factors that are associated with use of secondary surgery. Design Retrospective cohort study. Setting Forty-three paediatric hospitals across the USA. Patients Children with cleft lip and palate who underwent primary cleft palate repair from 1999 to 2013. Main outcome measures Time from primary cleft palate repair to secondary palate surgery. Results We identified 4939 children who underwent primary cleft palate repair. At 10 years after primary palate repair, 44% of children had undergone secondary palate surgery. Significant variation existed among hospitals (p<0.001); the proportion of children undergoing secondary surgery by 10 years ranged from 9% to 77% across hospitals. After adjusting for patient demographics, primary palate repair before 9 months of age was associated with an increased hazard of secondary palate surgery (initial HR 6.74, 95% CI 5.30 to 8.73). Postoperative antibiotics, surgeon procedure volume and hospital procedure volume were not associated with time to secondary surgery (p>0.05). Of the outcome variation attributable to hospitals and surgeons, between-hospital differences accounted for 59% (p<0.001), while between-surgeon differences accounted for 41% (p<0.001). Conclusions Substantial variation in the hazard of secondary palate surgery exists depending on a child’s age at primary palate repair and the hospital and surgeon performing their repair. Performing primary palate repair before 9 months of age substantially increases the hazard of secondary surgery. Further research is needed to identify other factors contributing to variation in palate surgery outcomes among hospitals and surgeons. PMID:29479567

Variation in Biomass Composition Components among Forage, Biomass, Sorghum-Sudangrass, and Sweet Sorghum Types

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

Stefaniak, T. R.; Dahlberg, J. A.; Bean, B. W.

2012-07-01

Alternative biomass sources must be developed if the United States is to meet the goal in the U.S. Energy Security Act of 2007 to derive 30% of its petroleum from renewable sources, and several different biomass crops are currently in development. Sorghum [Sorghum bicolor (L.) Moench] is one such crop that will be an important feedstock source for biofuel production. As composition influences productivity, there exists a need to understand the range in composition observed within the crop. The goal of this research was to assess the range in dietary fiber composition observed within different types of biomass sorghums. Amore » total of 152 sorghum samples were divided into the four end-use types of sorghum: biomass, forage, sorghum-sudangrass, and sweet. These samples were analyzed chemically using dietary fiber analysis performed at the National Renewable Energy Laboratory using published protocols. Significant variation among the groups was detected for glucan and ash. Positive and highly significant correlations were detected between structural carbohydrates in the biomass and sweet sorghums while many of these correlations were negative or not significant in the forage and sorghum-sudangrass types. In addition, a wide range of variation was present within each group indicating that there is potential to manipulate the composition of the crop.« less

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

PubMed

Hatadani, Luciane Mendes; Klaczko, Louis Bernard

2008-07-01

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

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

USGS Publications Warehouse

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

2004-01-01

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

Task-dependent signal variations in EEG error-related potentials for brain-computer interfaces

NASA Astrophysics Data System (ADS)

Iturrate, I.; Montesano, L.; Minguez, J.

2013-04-01

Objective. A major difficulty of brain-computer interface (BCI) technology is dealing with the noise of EEG and its signal variations. Previous works studied time-dependent non-stationarities for BCIs in which the user’s mental task was independent of the device operation (e.g., the mental task was motor imagery and the operational task was a speller). However, there are some BCIs, such as those based on error-related potentials, where the mental and operational tasks are dependent (e.g., the mental task is to assess the device action and the operational task is the device action itself). The dependence between the mental task and the device operation could introduce a new source of signal variations when the operational task changes, which has not been studied yet. The aim of this study is to analyse task-dependent signal variations and their effect on EEG error-related potentials.Approach. The work analyses the EEG variations on the three design steps of BCIs: an electrophysiology study to characterize the existence of these variations, a feature distribution analysis and a single-trial classification analysis to measure the impact on the final BCI performance.Results and significance. The results demonstrate that a change in the operational task produces variations in the potentials, even when EEG activity exclusively originated in brain areas related to error processing is considered. Consequently, the extracted features from the signals vary, and a classifier trained with one operational task presents a significant loss of performance for other tasks, requiring calibration or adaptation for each new task. In addition, a new calibration for each of the studied tasks rapidly outperforms adaptive techniques designed in the literature to mitigate the EEG time-dependent non-stationarities.

Transposable element distribution, abundance and role in genome size variation in the genus Oryza.

PubMed

Zuccolo, Andrea; Sebastian, Aswathy; Talag, Jayson; Yu, Yeisoo; Kim, HyeRan; Collura, Kristi; Kudrna, Dave; Wing, Rod A

2007-08-29

The genus Oryza is composed of 10 distinct genome types, 6 diploid and 4 polyploid, and includes the world's most important food crop - rice (Oryza sativa [AA]). Genome size variation in the Oryza is more than 3-fold and ranges from 357 Mbp in Oryza glaberrima [AA] to 1283 Mbp in the polyploid Oryza ridleyi [HHJJ]. Because repetitive elements are known to play a significant role in genome size variation, we constructed random sheared small insert genomic libraries from 12 representative Oryza species and conducted a comprehensive study of the repetitive element composition, distribution and phylogeny in this genus. Particular attention was paid to the role played by the most important classes of transposable elements (Long Terminal Repeats Retrotransposons, Long interspersed Nuclear Elements, helitrons, DNA transposable elements) in shaping these genomes and in their contributing to genome size variation. We identified the elements primarily responsible for the most strikingly genome size variation in Oryza. We demonstrated how Long Terminal Repeat retrotransposons belonging to the same families have proliferated to very different extents in various species. We also showed that the pool of Long Terminal Repeat Retrotransposons is substantially conserved and ubiquitous throughout the Oryza and so its origin is ancient and its existence predates the speciation events that originated the genus. Finally we described the peculiar behavior of repeats in the species Oryza coarctata [HHKK] whose placement in the Oryza genus is controversial. Long Terminal Repeat retrotransposons are the major component of the Oryza genomes analyzed and, along with polyploidization, are the most important contributors to the genome size variation across the Oryza genus. Two families of Ty3-gypsy elements (RIRE2 and Atlantys) account for a significant portion of the genome size variations present in the Oryza genus.

Identification of species and genetic variation in Taenia isolates from human and swine of North India.

PubMed

Singh, Satyendra K; Prasad, Kashi N; Singh, Aloukick K; Gupta, Kamlesh K; Chauhan, Ranjeet S; Singh, Amrita; Singh, Avinash; Rai, Ravi P; Pati, Binod K

2016-10-01

Taenia solium is the major cause of taeniasis and cysticercosis/neurocysticercosis (NCC) in the developing countries including India, but the existence of other Taenia species and genetic variation have not been studied in India. So, we studied the existence of different Taenia species, and sequence variation in Taenia isolates from human (proglottids and cysticerci) and swine (cysticerci) in North India. Amplification of cytochrome c oxidase subunit 1 gene (cox1) was done by polymerase chain reaction (PCR) followed by sequencing and phylogenetic analysis. We identified two species of Taenia i.e. T. solium and Taenia asiatica in our isolates. T. solium isolates showed similarity with Asian genotype and nucleotide variations from 0.25 to 1.01 %, whereas T. asiatica displayed nucleotide variations ranged from 0.25 to 0.5 %. These findings displayed the minimal genetic variations in North Indian isolates of T. solium and T. asiatica.

Deterministic and probabilistic analysis of damping device resistance under impact loads from nuclear fuel container drop

NASA Astrophysics Data System (ADS)

Kala, J.; Bajer, M.; Barnat, J.; Smutný, J.

2010-12-01

Pedestrian-induced vibrations are a criterion for serviceability. This loading is significant for light-weight footbridge structures, but was established as a basic loading for the ceilings of various ordinary buildings. Wide variations of this action exist. To verify the different conclusions of various authors, vertical pressure measurements invoked during walking were performed. In the article the approaches of different design codes are also shown.

Existence of a component corotating with the earth in high-latitude disturbance magnetic fields

NASA Technical Reports Server (NTRS)

Suzuki, A.; Kim, J. S.; Sugiura, M.

1982-01-01

A study of the data from the high-latitude North American IMS network of magnetic stations suggests that there is a component in substorm perturbations that corotates with the earth. It is as yet not certain whether the existence of this component stems from the corotation of a part of the magnetospheric plasma involved in the substorm mechanism or if it is a 'phase change' resulting from the control of the substorm manifestations by the earth's main magnetic field which is not axially symmetric. There are other geophysical phenomena showing a persistence of longitudinal variations corotating with the earth. These phenomena are of significance for a better understanding of ionosphere-magnetosphere coupling.

Geographic variations in female breast cancer incidence in relation to ambient air emissions of polycyclic aromatic hydrocarbons.

PubMed

Large, Courtney; Wei, Yudan

2017-07-01

A significant geographic variation of breast cancer incidence exists, with incidence rates being much higher in industrialized regions. The objective of the current study was to assess the role of environmental factors such as exposure to ambient air pollution, specifically carcinogenic polycyclic aromatic hydrocarbons (PAHs) that may be playing in the geographic variations in breast cancer incidence. Female breast cancer incidence and ambient air emissions of PAHs were examined in the northeastern and southeastern regions of the USA by analyzing data from the Surveillance, Epidemiology, and End Results (SEER) Program and the State Cancer Profiles of the National Cancer Institute and from the Environmental Protection Agency. Linear regression analysis was conducted to evaluate the association between PAH emissions and breast cancer incidence in unadjusted and adjusted models. Significantly higher age-adjusted incidence rates of female breast cancer were seen in northeastern SEER regions, when compared to southeastern regions, during the years of 2000-2012. After adjusting for potential confounders, emission densities of total PAHs and four carcinogenic individual PAHs (benzo[a]pyrene, dibenz[a,h]anthracene, naphthalene, and benzo[b]fluoranthene) showed a significantly positive association with annual incidence rates of breast cancer, with a β of 0.85 (p = 0.004), 58.37 (p = 0.010), 628.56 (p = 0.002), 0.44 (p = 0.041), and 77.68 (p = 0.002), respectively, among the northeastern and southeastern states. This study suggests a potential relationship between ambient air emissions of carcinogenic PAHs and geographic variations of female breast cancer incidence in the northeastern and southeastern US. Further investigations are needed to explore these interactions and elucidate the role of PAHs in regional variations of breast cancer incidence.

Biological variations in depression and anxiety between East and West.

PubMed

Chen, Po-Yu; Wang, Sheng-Chang; Poland, Russell E; Lin, Keh-Ming

2009-01-01

Ethnicity and culture represent important factors in shaping psychopathology as well as pharmacotherapeutic responses in psychiatric patients. A large body of literature, accumulated over the past several decades, demonstrates that these factors not only determine the metabolism and disposition of medications (pharmacokinetics), but also their interactions with therapeutic targets (pharmacodynamics). This article focuses on the impact of such variations on the diagnosis and treatment of depression and anxiety disorders between East and West. Genes controlling the expression of drug metabolizing enzymes as well as the function of the brain are highly polymorphic, and the patterns and distribution of these polymorphisms are typically divergent across ethnic groups. To the extent that these genetic patterns determine drug response, ethnic variations in these genetic dispositions will lead to differential responses in clinical settings. In addition, the expression of these genes is significantly influenced by environmental factors including diet as well as exposure to other natural products. Superimposed on these biological influences, culturally determined beliefs and behavioral patterns also profoundly influence patients' expectations of treatment response, adherence, and interactions with clinicians. In addition to pharmacotherapeutic responses, emerging data also indicate that significant ethnic variations exist in genetic polymorphisms and neurobiologic correlates (biomarkers) that may be associated with the vulnerability to psychiatric disorders. These considerations argue for the importance of examining biological variations across ethnic groups, especially in the clinical context, in terms of the assessment and treatment of psychiatric patients, and in our understanding of psychiatric phenomenology and nosology.

Interpretation of medical information acts by UK occupational physicians.

PubMed

Batty, Lucia; Glozier, Nick; Holland-Elliott, Kevin

2009-05-01

Difficulties arise in applying the Data Protection Act 1998 and the Access to Medical Reports Act 1988 in occupational health practice. There is no guidance on detailed aspects of applying these Acts in practice and consistent advice has proved difficult to obtain. To audit the understanding and practice of UK occupational physicians to see if a consensus view existed. A postal questionnaire sent to all UK-based Society of Occupational Medicine (SOM) members between December 2005 and June 2006. Responses were analysed using the SPSS 13.0 software. Responses were received from 726 SOM members, a response rate of 48%. The study revealed wide variation and a limited consensus in practice. Significant differences existed between doctors with a Diploma in Occupational Medicine and those with higher Faculty qualifications, between part-time and full-time practitioners and between doctors who qualified pre- and post-1974. The audit revealed wide variation in responding to clinical scenarios in relation to both the Access to Medical Reports and the Data Protection Acts. The findings have implications for clinical practice, policy and research. The majority of respondents reported that national guidance is needed.

Analysis of Classes of Superlinear Semipositone Problems with Nonlinear Boundary Conditions

NASA Astrophysics Data System (ADS)

Morris, Quinn A.

We study positive radial solutions for classes of steady state reaction diffusion problems on the exterior of a ball with both Dirichlet and nonlinear boundary conditions. We consider p-Laplacian problems (p > 1) with reaction terms which are superlinear at infinity and semipositone. In the case p = 2, using variational methods, we establish the existence of a solution, and via detailed analysis of the Green's function, we prove the positivity of the solution. In the case p ≠ 2, we again use variational methods to establish the existence of a solution, but the positivity of the solution is achieved via sophisticated a priori estimates. In the case p ≠ 2, the Green's function analysis is no longer available. Our results significantly enhance the literature on superlinear semipositone problems. Finally, we provide algorithms for the numerical generation of exact bifurcation curves for one-dimensional problems. In the autonomous case, we extend and analyze a quadrature method, and using nonlinear solvers in Mathematica, generate bifurcation curves. In the nonautonomous case, we employ shooting methods in Mathematica to generate bifurcation curves.

Extreme isotopic variations in the upper mantle: evidence from Ronda

NASA Astrophysics Data System (ADS)

Reisberg, Laurie; Zindler, Alan

1986-12-01

The Ronda Ultramafic Complex in southern Spain represents a piece of the Earth's mantle which has been tectonically emplaced into the crust. Nd and Sr isotopic analyses are presented for leached, hand-picked Cr-diopside separates prepared from 15 rock and 18 river sediment samples from Ronda. These results demonstrate that within this small, contiguous body there exists the entire range of Nd isotopic compositions, and much of the range of Sr compositions, found in rocks derived from the sub-oceanic mantle. The sediment cpx samples show that the average isotopic composition of the massif becomes progressively less "depleted" moving from SW to NE along the long axis of the massif. The rock cpx samples document 143Nd/ 144Nd variations from 0.5129 to 0.5126 and 87Sr/ 86Sr variations from 0.7031 to 0.7039 within a uniform outcrop less than 10 m in extent. Thus, extreme isotopic fluctuations exist over a wide range of wavelengths. Sr and Nd isotopes are generally inversely correlated, forming a trend on a Nd-Sr diagram that sharply crosscuts that of the "mantle array". Many of the 143Nd/ 144Nd values, and all of the Sm/Nd values, from one section of the massif are lower than that SCV015SCV0 of the bulk earth, implying that this region existed, or was influenced by a component which existed, in a LREE-enriched environment for a significant period of time. Among the sediment cpxs there is a positive correlation between 143Nd/ 144Nd and 147Sm/ 144Nd. The rock cpx separates display considerably more scatter. A simple, single-stage differentiation event starting with a uniform mantle source cannot explain these results. At least one episode of mixing with a LREE-enriched component is required. If these results from Ronda are typical of the upper mantle, basalts with different isotopic compositions need not derive from spatially separated mantle sources.

An analysis of periodicities in the 1470 to 1974 Beijing precipitation record

NASA Technical Reports Server (NTRS)

Hameed, S.; Yeh, W. M.; Cess, R. D.; Wang, W. C.; Li, M. T.

1983-01-01

An analyis of a time series consisting of an annual index of dryness/wetness for the years 1470 to 1974 in Beijing, China is presented. Its power spectrum shows that dominant cycles occur with long periods of the order of 80 years. Cycles with periods of 11 and 22 years are weak or non-existent, but a significant signal at 18.7 years (which is also the period of a component of the lunar tide generating force) is detected. The long term variations in Beijing precipitation appear to lag long term (Gleissberg) variations in solar activity by nearly 75 years. A pattern which spans nearly 150 years in the Beijing record is found to be repeated with notable similarity.

a Spatiotemporal Aggregation Query Method Using Multi-Thread Parallel Technique Based on Regional Division

NASA Astrophysics Data System (ADS)

Liao, S.; Chen, L.; Li, J.; Xiong, W.; Wu, Q.

2015-07-01

Existing spatiotemporal database supports spatiotemporal aggregation query over massive moving objects datasets. Due to the large amounts of data and single-thread processing method, the query speed cannot meet the application requirements. On the other hand, the query efficiency is more sensitive to spatial variation then temporal variation. In this paper, we proposed a spatiotemporal aggregation query method using multi-thread parallel technique based on regional divison and implemented it on the server. Concretely, we divided the spatiotemporal domain into several spatiotemporal cubes, computed spatiotemporal aggregation on all cubes using the technique of multi-thread parallel processing, and then integrated the query results. By testing and analyzing on the real datasets, this method has improved the query speed significantly.

Immunocompetence of the red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae): variation between developmental stages and sexes in populations in China.

PubMed

Shi, Zhang-Hong; Sun, Jiang-Hua

2010-11-01

Immune defense imposes fitness costs as well as benefits, so organisms should optimize, not maximize, their immune function through their life cycle. We investigated this issue in the red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae), which is a pine-killing invasive beetle in China, though it is usually considered as a secondary pest in its native range of North America. We hypothesized that pathogen pressure may affect these beetles differently throughout their life history. We measured the insect's immunocompetence throughout life, determining encapsulation ability and phenoloxidase activity in larval stages, pupae and adults. Pupae had the highest encapsulation ability, but encapsulation was not different between final instar larvae and adults. Phenoloxidase (PO) activity was highest in final instar larvae and pupae, followed by the second instar larvae and adults. Total phenoloxidase activity increased significantly from the second instar larval stage to pupae, and then decreased in adults. Although the second instar larvae had the lowest phenoloxidase activity, more than 90% of total PO existed in the hemolymph in the form of the active enzyme, as compared with pupae, in which over 60% of PO occurred as a proenzyme. Both active PO and total PO were much higher in females than in males, though no significant differences were detected between the encapsulation ability of male and female adults. This result suggests the existence of a sexual dimorphism of immunocompetence in D. valens adults. Variations in immunocompetence across developmental stages suggest that D. valens adopts diverse investment strategies in immunocompetence during different stages. Potential reasons for variation in immunocompetence among developmental stages and between the sexes of D. valens are discussed. Copyright 2010 Elsevier Ltd. All rights reserved.

Causes of the mid-latitudinal daytime NmF2 semi-annual anomaly at solar minimum

NASA Astrophysics Data System (ADS)

Pavlov, A. V.

2018-04-01

Ionospheric ionosonde and radar observations and theoretical calculations of the F2-layer peak altitude, hmF2, and number density, NmF2, over Millstone Hill during winter, spring, summer, and autumn geomagnetically quiet time periods at low solar activity are used to study the causes of the observed daytime NmF2 semi-annual anomaly. It follows from the model simulations that this anomalous phenomenon arises in the ionosphere mainly as a result of seasonal variations of the following atmospheric parameters: (1) the plasma drift along geomagnetic field lines due to corresponding changes in neutral wind components, (2) temperature and number densities of the neutral atmosphere, and (3) an optical thickness of the atmosphere caused by the dependence of the solar zenith angle on the day of the year for the same solar local time. Seasonal variations of the production rate unexcited O+ ions due to chemical reactions involving electronically excited O+ ions contribute to the formation of the NmF2 semi-annual anomaly during the predominant part of the existence time of this anomalous phenomenon. However, these seasonal variations are not significant, and this mechanism should be considered only as an additional source of the NmF2 semi-annual anomaly during its time of existence. The reactions of unexcited O+ ions with vibrationally excited N2 and O2 cause only weak changes of NmF2 and these changes are close in magnitude at a given solar local time during the winter, spring, summer, and autumn daytime conditions under consideration. Ignoring these reactions cannot produce a significant impact on the formation of the NmF2 semi-annual anomaly.

Comparing NICU teamwork and safety climate across two commonly used survey instruments.

PubMed

Profit, Jochen; Lee, Henry C; Sharek, Paul J; Kan, Peggy; Nisbet, Courtney C; Thomas, Eric J; Etchegaray, Jason M; Sexton, Bryan

2016-12-01

Measurement and our understanding of safety culture are still evolving. The objectives of this study were to assess variation in safety and teamwork climate and in the neonatal intensive care unit (NICU) setting, and compare measurement of safety culture scales using two different instruments (Safety Attitudes Questionnaire (SAQ) and Hospital Survey on Patient Safety Culture (HSOPSC)). Cross-sectional survey study of a voluntary sample of 2073 (response rate 62.9%) health professionals in 44 NICUs. To compare survey instruments, we used Spearman's rank correlation coefficients. We also compared similar scales and items across the instruments using t tests and changes in quartile-level performance. We found significant variation across NICUs in safety and teamwork climate scales of SAQ and HSOPSC (p<0.001). Safety scales (safety climate and overall perception of safety) and teamwork scales (teamwork climate and teamwork within units) of the two instruments correlated strongly (safety r=0.72, p<0.001; teamwork r=0.67, p<0.001). However, the means and per cent agreements for all scale scores and even seemingly similar item scores were significantly different. In addition, comparisons of scale score quartiles between the two instruments revealed that half of the NICUs fell into different quartiles when translating between the instruments. Large variation and opportunities for improvement in patient safety culture exist across NICUs. Important systematic differences exist between SAQ and HSOPSC such that these instruments should not be used interchangeably. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Consensus training: an effective tool to minimize variations in periodontal diagnosis and treatment planning among dental faculty and students.

PubMed

John, Vanchit; Lee, Seung-Jun; Prakasam, Sivaraman; Eckert, George J; Maupome, Gerardo

2013-08-01

Considerable disagreements and variations exist in diagnosis and treatment planning of periodontal disease. Achieving high interrater periodontal diagnosis can prove challenging. The objectives of this study were to measure variations in periodontal diagnosis and treatment planning among predoctoral periodontics faculty members after consensus training and to compare such variation with those identified in third- and fourth-year dental students. Nine electronically stored case vignettes and survey instruments were made available to eighteen faculty members and twenty dental students under standardized conditions. A chi-square test was used to compare responses between groups, and multirater kappa tests were used to evaluate interrater agreement/reliability. Of the nine cases, only one differed between groups significantly in terms of treatment. Also, third-year students differed from fourth-year students on the diagnosis of aggressive periodontitis versus chronic periodontitis. Most respondents were able to distinguish clearly among diagnoses of chronic periodontitis, aggressive periodontitis, and gingivitis. This study established a baseline assessment of the current status of consensus after training. We will reassess variations after addressing the specific challenges identified. Programs designed and implemented to help decrease the variation in periodontal diagnosis and treatment planning among faculty members may ultimately translate into better agreement and better standardization of dental instruction.

Significant population genetic structure detected in the rock bream Oplegnathus fasciatus (Temminck & Schlegel, 1844) inferred from fluorescent-AFLP analysis

NASA Astrophysics Data System (ADS)

Xiao, Yongshuang; Ma, Daoyuan; Xu, Shihong; Liu, Qinghua; Wang, Yanfeng; Xiao, Zhizhong; Li, Jun

2016-05-01

Oplegnathus fasciatus (rock bream) is a commercial rocky reef fish species in East Asia that has been considered for aquaculture. We estimated the population genetic diversity and population structure of the species along the coastal waters of China using fluorescent-amplified fragment length polymorphisms technology. Using 53 individuals from three populations and four pairs of selective primers, we amplified 1 264 bands, 98.73% of which were polymorphic. The Zhoushan population showed the highest Nei's genetic diversity and Shannon genetic diversity. The results of analysis of molecular variance (AMOVA) showed that 59.55% of genetic variation existed among populations and 40.45% occurred within populations, which indicated that a significant population genetic structure existed in the species. The pairwise fixation index F st ranged from 0.20 to 0.63 and were significant after sequential Bonferroni correction. The topology of an unweighted pair group method with arithmetic mean tree showed two significant genealogical branches corresponding to the sampling locations of North and South China. The AMOVA and STRUCTURE analyses suggested that the O. fasciatus populations examined should comprise two stocks.

Genetic variation in the USDA Chamaecrista fasciculata collection

USDA-ARS?s Scientific Manuscript database

Germplasm collections serve as critical repositories of genetic variation. Characterizing genetic diversity in existing collections is necessary to maximize their utility and to guide future collecting efforts. We have used AFLP markers to characterize genetic variation in the USDA germplasm collect...

Can Yeast (S. cerevisiae) Metabolic Volatiles Provide Polymorphic Signaling?

PubMed Central

Arguello, J. Roman; Sellanes, Carolina; Lou, Yann Ru; Raguso, Robert A.

2013-01-01

Chemical signaling between organisms is a ubiquitous and evolutionarily dynamic process that helps to ensure mate recognition, location of nutrients, avoidance of toxins, and social cooperation. Evolutionary changes in chemical communication systems progress through natural variation within the organism generating the signal as well as the responding individuals. A promising yet poorly understood system with which to probe the importance of this variation exists between D. melanogaster and S. cerevisiae. D. melanogaster relies on yeast for nutrients, while also serving as a vector for yeast cell dispersal. Both are outstanding genetic and genomic models, with Drosophila also serving as a preeminent model for sensory neurobiology. To help develop these two genetic models as an ecological model, we have tested if - and to what extent - S. cerevisiae is capable of producing polymorphic signaling through variation in metabolic volatiles. We have carried out a chemical phenotyping experiment for 14 diverse accessions within a common garden random block design. Leveraging genomic sequences for 11 of the accessions, we ensured a genetically broad sample and tested for phylogenetic signal arising from phenotypic dataset. Our results demonstrate that significant quantitative differences for volatile blends do exist among S. cerevisiae accessions. Of particular ecological relevance, the compounds driving the blend differences (acetoin, 2-phenyl ethanol and 3-methyl-1-butanol) are known ligands for D. melanogasters chemosensory receptors, and are related to sensory behaviors. Though unable to correlate the genetic and volatile measurements, our data point clear ways forward for behavioral assays aimed at understanding the implications of this variation. PMID:23990899

An evaluation of relation between the relative parallelism of occlusal plane to ala-tragal line and variation in the angulation of Po-Na-ANS angle in dentulous subjects: A cephalometric study

PubMed Central

Shetty, Sanath; Shenoy, K. Kamalakanth; Ninan, Justin; Mahaseth, Pranay

2015-01-01

Aims: The aim was to evaluate if any correlation exists between variation in angulation of Po-Na-ANS angle and relative parallelism of the occlusal plane to the different tragal levels of the ear in dentulous subjects. Methodology: A total of 200 subjects were selected for the study. A custom made occlusal plane analyzer was used to determine the posterior point of the ala-tragal line. The lateral cephalogram was shot for each of the subjects. The points Porion, Nasion, and Anterior Nasal Spine were located and the angle formed between these points was measured. Statistical Analysis Used: Fischer's exact test was used to find the correlation between Po-Na-ANS angle and relative parallelism of the occlusal plane to the ala-tragal line at different tragal levels. Results: Statistical analysis showed no significant correlation between Po-Na-ANS angle and relative parallelism of an occlusal plane at different tragal levels, and an inferior point on the tragus was the most common. Conclusion: Irrespective of variations in the Po-Na-ANS angle, no correlation exists between the variation in the angulations of Po-Na-ANS angle and the relative parallelism of occlusal plane to the ala-tragal line at different tragal levels. Furthermore, in a large number of subjects (54%), the occlusal plane was found parallel to a line joining the inferior border of the ala of the nose and the inferior part of the tragus. PMID:26929506

Efficient identification of context dependent subgroups of risk from genome wide association studies

PubMed Central

Dyson, Greg; Sing, Charles F.

2014-01-01

We have developed a modified Patient Rule-Induction Method (PRIM) as an alternative strategy for analyzing representative samples of non-experimental human data to estimate and test the role of genomic variations as predictors of disease risk in etiologically heterogeneous sub-samples. A computational limit of the proposed strategy is encountered when the number of genomic variations (predictor variables) under study is large (> 500) because permutations are used to generate a null distribution to test the significance of a term (defined by values of particular variables) that characterizes a sub-sample of individuals through the peeling and pasting processes. As an alternative, in this paper we introduce a theoretical strategy that facilitates the quick calculation of Type I and Type II errors in the evaluation of terms in the peeling and pasting processes carried out in the execution of a PRIM analysis that are underestimated and non-existent, respectively, when a permutation-based hypothesis test is employed. The resultant savings in computational time makes possible the consideration of larger numbers of genomic variations (an example genome wide association study is given) in the selection of statistically significant terms in the formulation of PRIM prediction models. PMID:24570412

Individual differences, density dependence and offspring birth traits in a population of red deer

PubMed Central

Stopher, Katie V; Pemberton, Josephine M; Clutton-Brock, Tim H; Coulson, Tim

2008-01-01

Variation between individuals is an essential component of natural selection and evolutionary change, but it is only recently that the consequences of persistent differences between individuals on population dynamics have been considered. In particular, few authors have addressed whether interactions exist between individual quality and environmental variation. In part, this is due to the difficulties of collecting sufficient data, but also the challenge of defining individual quality. Using a long-established study population of red deer, Cervus elaphus, inhabiting the North Block of the Isle of Rum, and three quality measures, this paper investigates how differences in maternal quality affect variation in birth body mass and date, as population density varies, and how this differs depending on the sex of the offspring and the maternal quality measure used. Significant interactions between maternal quality, measured as a hind's total contribution to population growth, and population density are reported for birth mass, but only for male calves. Analyses using dominance or age at primiparity to define maternal quality showed no significant interactions with population density, highlighting the difficulties of defining a consistent measure of individual quality. PMID:18522909

Toward Failure Modeling In Complex Dynamic Systems: Impact of Design and Manufacturing Variations

NASA Technical Reports Server (NTRS)

Tumer, Irem Y.; McAdams, Daniel A.; Clancy, Daniel (Technical Monitor)

2001-01-01

When designing vehicle vibration monitoring systems for aerospace devices, it is common to use well-established models of vibration features to determine whether failures or defects exist. Most of the algorithms used for failure detection rely on these models to detect significant changes during a flight environment. In actual practice, however, most vehicle vibration monitoring systems are corrupted by high rates of false alarms and missed detections. Research conducted at the NASA Ames Research Center has determined that a major reason for the high rates of false alarms and missed detections is the numerous sources of statistical variations that are not taken into account in the. modeling assumptions. In this paper, we address one such source of variations, namely, those caused during the design and manufacturing of rotating machinery components that make up aerospace systems. We present a novel way of modeling the vibration response by including design variations via probabilistic methods. The results demonstrate initial feasibility of the method, showing great promise in developing a general methodology for designing more accurate aerospace vehicle vibration monitoring systems.

Volumetric analysis of maxillary sinuses of Zulu and European crania by helical, multislice computed tomography.

PubMed

Fernandes, C L

2004-11-01

The volumes of the maxillary sinuses are of interest to surgeons operating endoscopically as variation in maxillary sinus volume may mean variation in anatomical landmarks. Other surgical disciplines, such as dentistry, maxillo-facial surgery and plastic surgery, may benefit from this information. To compare the maxillary sinus volumes of dried crania from cadavers of European and Zulu descent, with respect to ethnic group and gender. Helical, multislice computed tomography (CT) was performed using 1-mm coronal slices. The area for each slice was obtained by tracing the outline of each slice. The CT machine calculated a volume by totalling the slices for each sinus. Ethnic and gender variations were found in the different groups. It was found that European crania had significantly larger antral volumes than Zulu crania and men had larger volumes than women. Race and gender interaction was also assessed, as was maxillary sinus side. A variation in maxillary sinus volume between different ethnic groups and genders exists, and surgeons operating in this region should be aware of this.

Quantifying heterogeneity in human tumours using MRI and PET.

PubMed

Asselin, Marie-Claude; O'Connor, James P B; Boellaard, Ronald; Thacker, Neil A; Jackson, Alan

2012-03-01

Most tumours, even those of the same histological type and grade, demonstrate considerable biological heterogeneity. Variations in genomic subtype, growth factor expression and local microenvironmental factors can result in regional variations within individual tumours. For example, localised variations in tumour cell proliferation, cell death, metabolic activity and vascular structure will be accompanied by variations in oxygenation status, pH and drug delivery that may directly affect therapeutic response. Documenting and quantifying regional heterogeneity within the tumour requires histological or imaging techniques. There is increasing evidence that quantitative imaging biomarkers can be used in vivo to provide important, reproducible and repeatable estimates of tumoural heterogeneity. In this article we review the imaging methods available to provide appropriate biomarkers of tumour structure and function. We also discuss the significant technical issues involved in the quantitative estimation of heterogeneity and the range of descriptive metrics that can be derived. Finally, we have reviewed the existing clinical evidence that heterogeneity metrics provide additional useful information in drug discovery and development and in clinical practice. Copyright © 2012 Elsevier Ltd. All rights reserved.

A sibling method for identifying vQTLs

PubMed Central

Domingue, Ben; Dawes, Christopher; Boardman, Jason; Siegal, Mark

2018-01-01

The propensity of a trait to vary within a population may have evolutionary, ecological, or clinical significance. In the present study we deploy sibling models to offer a novel and unbiased way to ascertain loci associated with the extent to which phenotypes vary (variance-controlling quantitative trait loci, or vQTLs). Previous methods for vQTL-mapping either exclude genetically related individuals or treat genetic relatedness among individuals as a complicating factor addressed by adjusting estimates for non-independence in phenotypes. The present method uses genetic relatedness as a tool to obtain unbiased estimates of variance effects rather than as a nuisance. The family-based approach, which utilizes random variation between siblings in minor allele counts at a locus, also allows controls for parental genotype, mean effects, and non-linear (dominance) effects that may spuriously appear to generate variation. Simulations show that the approach performs equally well as two existing methods (squared Z-score and DGLM) in controlling type I error rates when there is no unobserved confounding, and performs significantly better than these methods in the presence of small degrees of confounding. Using height and BMI as empirical applications, we investigate SNPs that alter within-family variation in height and BMI, as well as pathways that appear to be enriched. One significant SNP for BMI variability, in the MAST4 gene, replicated. Pathway analysis revealed one gene set, encoding members of several signaling pathways related to gap junction function, which appears significantly enriched for associations with within-family height variation in both datasets (while not enriched in analysis of mean levels). We recommend approximating laboratory random assignment of genotype using family data and more careful attention to the possible conflation of mean and variance effects. PMID:29617452

Robust inference of population structure for ancestry prediction and correction of stratification in the presence of relatedness.

PubMed

Conomos, Matthew P; Miller, Michael B; Thornton, Timothy A

2015-05-01

Population structure inference with genetic data has been motivated by a variety of applications in population genetics and genetic association studies. Several approaches have been proposed for the identification of genetic ancestry differences in samples where study participants are assumed to be unrelated, including principal components analysis (PCA), multidimensional scaling (MDS), and model-based methods for proportional ancestry estimation. Many genetic studies, however, include individuals with some degree of relatedness, and existing methods for inferring genetic ancestry fail in related samples. We present a method, PC-AiR, for robust population structure inference in the presence of known or cryptic relatedness. PC-AiR utilizes genome-screen data and an efficient algorithm to identify a diverse subset of unrelated individuals that is representative of all ancestries in the sample. The PC-AiR method directly performs PCA on the identified ancestry representative subset and then predicts components of variation for all remaining individuals based on genetic similarities. In simulation studies and in applications to real data from Phase III of the HapMap Project, we demonstrate that PC-AiR provides a substantial improvement over existing approaches for population structure inference in related samples. We also demonstrate significant efficiency gains, where a single axis of variation from PC-AiR provides better prediction of ancestry in a variety of structure settings than using 10 (or more) components of variation from widely used PCA and MDS approaches. Finally, we illustrate that PC-AiR can provide improved population stratification correction over existing methods in genetic association studies with population structure and relatedness. © 2015 WILEY PERIODICALS, INC.

Isozyme variation in wild and cultivated pineapple

USDA-ARS?s Scientific Manuscript database

Isozyme variation was studied in 161 accessions of pineapple including four species of Ananas and one of Pseudananas. Six enzyme systems (ADH, GPI, PGM, SKDH, TPI, UGPP) involving seven putative loci revealed 35 electromorphs . Considerable variation exists within and between species of Ananas. Sixt...

Diurnal flight behavior of Ichneumonoidea (Insecta: Hymenoptera) related to environmental factors in a tropical dry forest.

PubMed

González-Moreno, A; Bordera, S; Leirana-Alcocer, J; Delfín-González, H

2012-06-01

The biology and behavior of insects are strongly influenced by environmental conditions such as temperature and precipitation. Because some of these factors present a within day variation, they may be causing variations on insect diurnal flight activity, but scant information exists on the issue. The aim of this work was to describe the patterns on diurnal variation of the abundance of Ichneumonoidea and their relation with relative humidity, temperature, light intensity, and wind speed. The study site was a tropical dry forest at Ría Lagartos Biosphere Reserve, Mexico; where correlations between environmental factors (relative humidity, temperature, light, and wind speed) and abundance of Ichneumonidae and Braconidae (Hymenoptera: Ichneumonoidea) were estimated. The best regression model for explaining abundance variation was selected using the second order Akaike Information Criterion. The optimum values of temperature, humidity, and light for flight activity of both families were also estimated. Ichneumonid and braconid abundances were significantly correlated to relative humidity, temperature, and light intensity; ichneumonid also showed significant correlations to wind speed. The second order Akaike Information Criterion suggests that in tropical dry conditions, relative humidity is more important that temperature for Ichneumonoidea diurnal activity. Ichneumonid wasps selected toward intermediate values of relative humidity, temperature and the lowest wind speeds; while Braconidae selected for low values of relative humidity. For light intensity, braconids presented a positive selection for moderately high values.

Compilation of 1993 Annual Reports of the Navy ELF Communications System Ecological Monitoring Program

DTIC Science & Technology

1994-04-01

variation in non-treatment factors that may affect growth or health such as soil, stand conditions and background and treatment EM field levels. The time...diameter growth residuals were much greater than expected given existing climatic conditions . In 1992, when the antenna returned to full power operation...growing seasons. If an enviromental factor which is not accounted for in the growth model significantly impacts seasonal height growth , then the observed

[Relationships between decomposition rate of leaf litter and initial quality across the alpine timberline ecotone in Western Sichuan, China].

PubMed

Yang, Lin; Deng, Chang-chun; Chen Ya-mei; He, Run-lian; Zhang, Jian; Liu, Yang

2015-12-01

The relationships between litter decomposition rate and their initial quality of 14 representative plants in the alpine forest ecotone of western Sichuan were investigated in this paper. The decomposition rate k of the litter ranged from 0.16 to 1.70. Woody leaf litter and moss litter decomposed much slower, and shrubby litter decomposed a little faster. Then, herbaceous litters decomposed fastest among all plant forms. There were significant linear regression relationships between the litter decomposition rate and the N content, lignin content, phenolics content, C/N, C/P and lignin/N. Lignin/N and hemicellulose content could explain 78.4% variation of the litter decomposition rate (k) by path analysis. The lignin/N could explain 69.5% variation of k alone, and the direct path coefficient of lignin/N on k was -0.913. Principal component analysis (PCA) showed that the contribution rate of the first sort axis to k and the decomposition time (t) reached 99.2%. Significant positive correlations existed between lignin/N, lignin content, C/N, C/P and the first sort axis, and the closest relationship existed between lignin/N and the first sort axis (r = 0.923). Lignin/N was the key quality factor affecting plant litter decomposition rate across the alpine timberline ecotone, with the higher the initial lignin/N, the lower the decomposition rate of leaf litter.

Temporal variations in the potential hydrological performance of extensive green roof systems

NASA Astrophysics Data System (ADS)

De-Ville, Simon; Menon, Manoj; Stovin, Virginia

2018-03-01

Existing literature provides contradictory information about variation in potential green roof hydrological performance over time. This study has evaluated a long-term hydrological monitoring record from a series of extensive green roof test beds to identify long-term evolutions and sub-annual (seasonal) variations in potential hydrological performance. Monitoring of nine differently-configured extensive green roof test beds took place over a period of 6 years in Sheffield, UK. Long-term evolutions and sub-annual trends in maximum potential retention performance were identified through physical monitoring of substrate field capacity over time. An independent evaluation of temporal variations in detention performance was undertaken through the fitting of reservoir-routing model parameters. Aggregation of the resulting retention and detention variations permitted the prediction of extensive green roof hydrological performance in response to a 1-in-30-year 1-h summer design storm for Sheffield, UK, which facilitated the comparison of multi and sub-annual hydrological performance variations. Sub-annual (seasonal) variation was found to be significantly greater than long-term evolution. Potential retention performance increased by up to 12% after 5-years, whilst the maximum sub-annual variation in potential retention was 27%. For vegetated roof configurations, a 4% long-term improvement was observed for detention performance, compared to a maximum 63% sub-annual variation. Consistent long-term reductions in detention performance were observed in unvegetated roof configurations, with a non-standard expanded-clay substrate experiencing a 45% reduction in peak attenuation over 5-years. Conventional roof configurations exhibit stable long-term hydrological performance, but are nonetheless subject to sub-annual variation.

He nui na ala e hiki aku ai: Factors Influencing Phonetic Variation in the Hawaiian Word "keia"

ERIC Educational Resources Information Center

Drager, Katie; Comstock, Bethany Kaleialohapau'ole Chun; Kneubuhl, Hina Puamohala

2017-01-01

Apart from a handful of studies (e.g., Kinney 1956), linguists know little about what variation exists in Hawaiian and what factors constrain the variation. In this paper, we present an analysis of phonetic variation in the word "keia," meaning "this," examining the social, linguistic, and probabilistic factors that constrain…

Unified Sequence-Based Association Tests Allowing for Multiple Functional Annotations and Meta-analysis of Noncoding Variation in Metabochip Data.

PubMed

He, Zihuai; Xu, Bin; Lee, Seunggeun; Ionita-Laza, Iuliana

2017-09-07

Substantial progress has been made in the functional annotation of genetic variation in the human genome. Integrative analysis that incorporates such functional annotations into sequencing studies can aid the discovery of disease-associated genetic variants, especially those with unknown function and located outside protein-coding regions. Direct incorporation of one functional annotation as weight in existing dispersion and burden tests can suffer substantial loss of power when the functional annotation is not predictive of the risk status of a variant. Here, we have developed unified tests that can utilize multiple functional annotations simultaneously for integrative association analysis with efficient computational techniques. We show that the proposed tests significantly improve power when variant risk status can be predicted by functional annotations. Importantly, when functional annotations are not predictive of risk status, the proposed tests incur only minimal loss of power in relation to existing dispersion and burden tests, and under certain circumstances they can even have improved power by learning a weight that better approximates the underlying disease model in a data-adaptive manner. The tests can be constructed with summary statistics of existing dispersion and burden tests for sequencing data, therefore allowing meta-analysis of multiple studies without sharing individual-level data. We applied the proposed tests to a meta-analysis of noncoding rare variants in Metabochip data on 12,281 individuals from eight studies for lipid traits. By incorporating the Eigen functional score, we detected significant associations between noncoding rare variants in SLC22A3 and low-density lipoprotein and total cholesterol, associations that are missed by standard dispersion and burden tests. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Across the Great Divide: The Effects of Technology in Secondary Biology Classrooms

NASA Astrophysics Data System (ADS)

Worley, Johnny Howard, II

This study investigates the relationship between technology use and student achievement in public high school across North Carolina. The purpose of this study was to determine whether a digital divide (differences in technology utilization based on student demographics of race/ethnicity, gender, socioeconomic status, and municipality) exists among schools and whether those differences relate to student achievement in high school biology classrooms. The study uses North Carolina end-of-course (EOC) data for biology to analyze student demographic data and assessment results from the 2010-2011 school year from the North Carolina Department of Public Instruction. The data analyses use descriptive and factorial univariate statistics to determine the existence of digital divides and their effects on biology achievement. Analysis of these data described patterns of technology use to determine whether potential variances resulted in a digital divide. Specific technology uses were identified in the data and then their impact on biology achievement scores within various demographic groups was examined. Research findings revealed statistically significant variations of use within different population groups. Despite being statistically significant, the relevance of the association in the variations was minimal at best -- based on the effect scale established by Cohen (1988). Additional factorial univariate analyses were employed to determine potential relationships between technology use and student achievement. The data revealed that technology use did not influence the variation of student achievement scale scores as much as race/ethnicity and socioeconomic status. White students outperformed Hispanic students by an average of three scale score points and Black students by an average of six scale score points. Technology use alone averaged less than a one point difference in mean scale scores, and only when interacting with race, gender, and/or SES did the mean difference increase. However, this increase within the context of the biology scale score range was negligible. This study contributes to the existing body of research on the effects of technology use on student achievement and its influence within various student demographic groups and municipalities. The study also provides additional research information for effective technology utilization, implementation, and instruction in educational environments.

Regional- and local-scale variations in benthic megafaunal composition at the Arctic deep-sea observatory HAUSGARTEN

NASA Astrophysics Data System (ADS)

Taylor, J.; Krumpen, T.; Soltwedel, T.; Gutt, J.; Bergmann, M.

2016-02-01

The Long-Term Ecological Research (LTER) observatory HAUSGARTEN, in the eastern Fram Strait, provides us the valuable ability to study the composition of benthic megafaunal communities through the analysis of seafloor photographs. This, in combination with extensive sampling campaigns, which have yielded a unique data set on faunal, bacterial, biogeochemical and geological properties, as well as on hydrography and sedimentation patterns, allows us to address the question of why variations in megafaunal community structure and species distribution exist within regional (60-110 km) and local (<4 km) scales. Here, we present first results from the latitudinal HAUSGARTEN gradient, consisting of three different stations (N3, HG-IV, S3) between 78°30‧N and 79°45‧N (2351-2788 m depth), obtained via the analysis of images acquired by a towed camera (OFOS-Ocean Floor Observation System) in 2011. We assess variability in megafaunal densities, species composition and diversity as well as biotic and biogenic habitat features, which may cause the patterns observed. While there were significant regional-scale differences in megafaunal composition and densities between the stations (N3=26.74±0.63; HG-IV=11.21±0.25; S3=18.34±0.39 individuals m-2), significant local differences were only found at HG-IV. Regional-scale variations may be due to the significant differences in ice coverage at each station as well as the different quantities of protein available, whereas local-scale differences at HG-IV may be a result of variation in bottom topography or factors not yet identified.

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

PubMed Central

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

2014-01-01

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

Allozyme variation in spineless Pejibaye (Bactris gasipaes Kunth)

USDA-ARS?s Scientific Manuscript database

Isozyme variation was studied in 161 accessions of pineapple including four species of Ananas and one of Pseudananas. Six enzyme systems (ADH, GPI, PGM, SKDH, TPI, UGPP) involving seven putative loci revealed 35 electromorphs . Considerable variation exists within and between species of Ananas. Sixt...

Statistical analysis of aerosol species, trace gasses, and meteorology in Chicago.

PubMed

Binaku, Katrina; O'Brien, Timothy; Schmeling, Martina; Fosco, Tinamarie

2013-09-01

Both canonical correlation analysis (CCA) and principal component analysis (PCA) were applied to atmospheric aerosol and trace gas concentrations and meteorological data collected in Chicago during the summer months of 2002, 2003, and 2004. Concentrations of ammonium, calcium, nitrate, sulfate, and oxalate particulate matter, as well as, meteorological parameters temperature, wind speed, wind direction, and humidity were subjected to CCA and PCA. Ozone and nitrogen oxide mixing ratios were also included in the data set. The purpose of statistical analysis was to determine the extent of existing linear relationship(s), or lack thereof, between meteorological parameters and pollutant concentrations in addition to reducing dimensionality of the original data to determine sources of pollutants. In CCA, the first three canonical variate pairs derived were statistically significant at the 0.05 level. Canonical correlation between the first canonical variate pair was 0.821, while correlations of the second and third canonical variate pairs were 0.562 and 0.461, respectively. The first canonical variate pair indicated that increasing temperatures resulted in high ozone mixing ratios, while the second canonical variate pair showed wind speed and humidity's influence on local ammonium concentrations. No new information was uncovered in the third variate pair. Canonical loadings were also interpreted for information regarding relationships between data sets. Four principal components (PCs), expressing 77.0 % of original data variance, were derived in PCA. Interpretation of PCs suggested significant production and/or transport of secondary aerosols in the region (PC1). Furthermore, photochemical production of ozone and wind speed's influence on pollutants were expressed (PC2) along with overall measure of local meteorology (PC3). In summary, CCA and PCA results combined were successful in uncovering linear relationships between meteorology and air pollutants in Chicago and aided in determining possible pollutant sources.

Novel genetic capacitors and potentiators for the natural genetic variation of sensory bristles and their trait specificity in Drosophila melanogaster.

PubMed

Takahashi, Kazuo H

2015-11-01

Cryptic genetic variation (CGV) is defined as the genetic variation that has little effect on phenotypic variation under a normal condition, but contributes to heritable variation under environmental or genetic perturbations. Genetic buffering systems that suppress the expression of CGV and store it in a population are called genetic capacitors, and the opposite systems are called genetic potentiators. One of the best-known candidates for a genetic capacitor and potentiator is the molecular chaperone protein, HSP90, and one of its characteristics is that it affects the genetic variation in various morphological traits. However, it remains unclear whether the wide-ranging effects of HSP90 on a broad range of traits are a general feature of genetic capacitors and potentiators. In the current study, I searched for novel genetic capacitors and potentiators for quantitative bristle traits of Drosophila melanogaster and then investigated the trait specificity of their genetic buffering effect. Three bristle traits of D. melanogaster were used as the target traits, and the genomic regions with genetic buffering effects were screened using the 61 genomic deficiencies examined previously for genetic buffering effects in wing shape. As a result, four and six deficiencies with significant effects on increasing and decreasing the broad-sense heritability of the bristle traits were identified, respectively. Of the 18 deficiencies with significant effects detected in the current study and/or by the previous study, 14 showed trait-specific effects, and four affected the genetic buffering of both bristle traits and wing shape. This suggests that most genetic capacitors and potentiators exert trait-specific effects, but that general capacitors and potentiators with effects on multiple traits also exist. © 2015 John Wiley & Sons Ltd.

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

PubMed Central

Janzen, F. J.

1992-01-01

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

Characterising and correcting batch variation in an automated direct infusion mass spectrometry (DIMS) metabolomics workflow.

PubMed

Kirwan, J A; Broadhurst, D I; Davidson, R L; Viant, M R

2013-06-01

Direct infusion mass spectrometry (DIMS)-based untargeted metabolomics measures many hundreds of metabolites in a single experiment. While every effort is made to reduce within-experiment analytical variation in untargeted metabolomics, unavoidable sources of measurement error are introduced. This is particularly true for large-scale multi-batch experiments, necessitating the development of robust workflows that minimise batch-to-batch variation. Here, we conducted a purpose-designed, eight-batch DIMS metabolomics study using nanoelectrospray (nESI) Fourier transform ion cyclotron resonance mass spectrometric analyses of mammalian heart extracts. First, we characterised the intrinsic analytical variation of this approach to determine whether our existing workflows are fit for purpose when applied to a multi-batch investigation. Batch-to-batch variation was readily observed across the 7-day experiment, both in terms of its absolute measurement using quality control (QC) and biological replicate samples, as well as its adverse impact on our ability to discover significant metabolic information within the data. Subsequently, we developed and implemented a computational workflow that includes total-ion-current filtering, QC-robust spline batch correction and spectral cleaning, and provide conclusive evidence that this workflow reduces analytical variation and increases the proportion of significant peaks. We report an overall analytical precision of 15.9%, measured as the median relative standard deviation (RSD) for the technical replicates of the biological samples, across eight batches and 7 days of measurements. When compared against the FDA guidelines for biomarker studies, which specify an RSD of <20% as an acceptable level of precision, we conclude that our new workflows are fit for purpose for large-scale, high-throughput nESI DIMS metabolomics studies.

Identification of hydrological model parameter variation using ensemble Kalman filter

NASA Astrophysics Data System (ADS)

Deng, Chao; Liu, Pan; Guo, Shenglian; Li, Zejun; Wang, Dingbao

2016-12-01

Hydrological model parameters play an important role in the ability of model prediction. In a stationary context, parameters of hydrological models are treated as constants; however, model parameters may vary with time under climate change and anthropogenic activities. The technique of ensemble Kalman filter (EnKF) is proposed to identify the temporal variation of parameters for a two-parameter monthly water balance model (TWBM) by assimilating the runoff observations. Through a synthetic experiment, the proposed method is evaluated with time-invariant (i.e., constant) parameters and different types of parameter variations, including trend, abrupt change and periodicity. Various levels of observation uncertainty are designed to examine the performance of the EnKF. The results show that the EnKF can successfully capture the temporal variations of the model parameters. The application to the Wudinghe basin shows that the water storage capacity (SC) of the TWBM model has an apparent increasing trend during the period from 1958 to 2000. The identified temporal variation of SC is explained by land use and land cover changes due to soil and water conservation measures. In contrast, the application to the Tongtianhe basin shows that the estimated SC has no significant variation during the simulation period of 1982-2013, corresponding to the relatively stationary catchment properties. The evapotranspiration parameter (C) has temporal variations while no obvious change patterns exist. The proposed method provides an effective tool for quantifying the temporal variations of the model parameters, thereby improving the accuracy and reliability of model simulations and forecasts.

Habitat fragmentation causes bottlenecks and inbreeding in the European tree frog (Hyla arborea).

PubMed Central

Andersen, Liselotte W.; Fog, Kåre; Damgaard, Christian

2004-01-01

A genetic study of the European tree frog, Hyla arborea, in Denmark was undertaken to examine the population structure on mainland Jutland and the island of Lolland after a period of reduction in suitable habitat and population sizes. The two regions have experienced the same rate of habitat loss but fragmentation has been more severe on Lolland. Genetic variation based on 12 polymorphic DNA microsatellites was analysed in 494 tree frogs sampled from two ponds in Jutland and 10 ponds on Lolland. A significant overall deviation from Hardy-Weinberg expectations could be attributed to three ponds, all on Lolland. This was most probably caused by an inbreeding effect reducing fitness, which was supported by the observed significant negative correlation between larva survival and mean F(IS) value and mean individual inbreeding coefficient. A significant reduction in genetic variation (bottleneck) was detected in most of the ponds on Lolland. Population-structure analysis suggested the existence of at least 11 genetically different populations, corresponding to most of the sampled population units. The results indicated that the populations were unique genetic units and could be used to illustrate the migration pattern between newly established ponds arisen either by natural colonization of tree frogs or by artificial introduction. A high degree of pond fidelity in the tree frogs was suggested. A severe fragmentation process reducing population size and fitness within some of the populations probably caused the significant reduction in genetic variation of tree frog populations on Lolland. PMID:15306354

Historical explanation of genetic variation in the Mediterranean horseshoe bat Rhinolophus euryale (Chiroptera: Rhinolophidae) inferred from mitochondrial cytochrome-b and D-loop genes in Iran.

PubMed

Najafi, Nargess; Akmali, Vahid; Sharifi, Mozafar

2018-04-26

Molecular phylogeography and species distribution modelling (SDM) suggest that late Quaternary glacial cycles have portrayed a significant role in structuring current population genetic structure and diversity. Based on phylogenetic relationships using Bayesian inference and maximum likelihood of 535 bp mtDNA (D-loop) and 745 bp mtDNA (Cytb) in 62 individuals of the Mediterranean Horseshoe Bat, Rhinolophus euryale, from 13 different localities in Iran we identified two subspecific populations with differing population genetic structure distributed in southern Zagros Mts. and northern Elburz Mts. Analysis of molecular variance (AMOVA) obtained from D-loop sequences indicates that 21.18% of sequence variation is distributed among populations and 10.84% within them. Moreover, a degree of genetic subdivision, mainly attributable to the existence of significant variance among the two regions is shown (θCT = 0.68, p = .005). The positive and significant correlation between geographic and genetic distances (R 2  = 0.28, r = 0.529, p = .000) is obtained following controlling for environmental distance. Spatial distribution of haplotypes indicates that marginal population of the species in southern part of the species range have occupied this section as a glacial refugia. However, this genetic variation, in conjunction with results of the SDM shows a massive postglacial range expansion for R. euryale towards higher latitudes in Iran.

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

PubMed

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

2018-02-27

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

Modelling the horizontal structure of mid-latitude E(s) from its refraction effects on F-region echoes

NASA Astrophysics Data System (ADS)

Barnes, R. I.

1991-02-01

The observation of the refraction of F-region echoes presently reported implies that significant horizontal structure exists within some E(s) clouds. A modeling of the data collected with the Bribie Island HF radar indicates that wind shear variations can account for examples in which irregularities either pass through, or pass with, existing layers of E(s) which create the cloudy, nonblanketing variety of E(s). The blanketing variety of E(s) seems to have little or no horizontal structure, and most likely drifts with the same velocity as the irregularities which produce nonblanketing E(s). Irregularities with strong horizontal gradients act as diverging lenses, leading to an overestimation of cloud size via simple occulting geometry.

Ultraviolet continuum variability and visual flickering in the peculiar object MWC 560

NASA Technical Reports Server (NTRS)

Michalitsianos, A. G.; Perez, M.; Shore, S. N.; Maran, S. P.; Karovska, M.; Sonneborn, G.; Webb, J. R.; Barnes, Thomas G., III; Frueh, Marian L.; Oliversen, R. J.

1993-01-01

High-speed U-band photometry of the peculiar emission object MWC 560 obtained with the ground-based instrumentation, and V-band photometry obtained with the International Ultraviolet Explorer-Fine Error Sensor indicates irregular brightness variations are quasi-periodic. Multiple peaks of relative brightness power indicate statistically significant quasi periods existing in a range of 3-35 minutes, that are superposed on slower hourly varying components. We present a preliminary model that explains the minute and hourly time-scale variations in MWC 560 in terms of a velocity-shear instability that arises because a white dwarf magnetosphere impinges on an accretion disk. We also find evidence for Fe II multiplet pseudocontinuum absorption opacity in far-UV spectra of CH Cygni which is also present in MWC 560. Both CH Cyg and MWC 560 may be in an evolutionary stage that is characterized by strong UV continuum opacity which changes significantly during outburst, occurring before they permanently enter the symbiotic nebular emission phase.

Wide variation in hospital and physician payment rates evidence of provider market power.

PubMed

Ginsburg, Paul B

2010-11-01

Wide variation in private insurer payment rates to hospitals and physicians across and within local markets suggests that some providers, particularly hospitals, have significant market power to negotiate higher-than-competitive prices, according to a new study by the Center for Studying Health System Change (HSC). Looking across eight health care markets--Cleveland; Indianapolis; Los Angeles; Miami; Milwaukee; Richmond, Va.; San Francisco; and rural Wisconsin--average inpatient hospital payment rates of four large national insurers ranged from 147 percent of Medicare in Miami to 210 percent in San Francisco. In extreme cases, some hospitals command almost five times what Medicare pays for inpatient services and more than seven times what Medicare pays for outpatient care. Variation within markets was just as dramatic. For example, the hospital with prices at the 25th percentile of Los Angeles hospitals received 84 percent of Medicare rates for inpatient care, while the hospital with prices at the 75th percentile received 184 percent of Medicare rates. The highest-priced Los Angeles hospital with substantial inpatient claims volume received 418 percent of Medicare. While not as pronounced, significant variation in physician payment rates also exists across and within markets and by specialty. Few would characterize the variation in hospital and physician payment rates found in this study to be consistent with a highly competitive market. Purchasers and public policy makers can address provider market power, or the ability to negotiate higher-than-competitive prices, through two distinct approaches. One is to pursue market approaches to strengthen competitive forces, while the other is to constrain payment rates through regulation.

Global dimming and brightening: A review

NASA Astrophysics Data System (ADS)

Wild, Martin

2009-05-01

There is increasing evidence that the amount of solar radiation incident at the Earth's surface is not stable over the years but undergoes significant decadal variations. Here I review the evidence for these changes, their magnitude, their possible causes, their representation in climate models, and their potential implications for climate change. The various studies analyzing long-term records of surface radiation measurements suggest a widespread decrease in surface solar radiation between the 1950s and 1980s ("global dimming"), with a partial recovery more recently at many locations ("brightening"). There are also some indications for an "early brightening" in the first part of the 20th century. These variations are in line with independent long-term observations of sunshine duration, diurnal temperature range, pan evaporation, and, more recently, satellite-derived estimates, which add credibility to the existence of these changes and their larger-scale significance. Current climate models, in general, tend to simulate these decadal variations to a much lesser degree. The origins of these variations are internal to the Earth's atmosphere and not externally forced by the Sun. Variations are not only found under cloudy but also under cloud-free atmospheres, indicative of an anthropogenic contribution through changes in aerosol emissions governed by economic developments and air pollution regulations. The relative importance of aerosols, clouds, and aerosol-cloud interactions may differ depending on region and pollution level. Highlighted are further potential implications of dimming and brightening for climate change, which may affect global warming, the components and intensity of the hydrological cycle, the carbon cycle, and the cryosphere among other climate elements.

[Variations of the nutritional condition of lobsters Panulirus argus (Decapoda: Palinuridae) in Eastern region of the Gulf of Batabanó, Cuba].

PubMed

Lopeztegui Castillo, Alexander; Capetillo Piñar, Norberto; Betanzos Vega, Abel

2012-03-01

Nutritional condition can affect survival and growth rate of crustaceans, and this is mostly affected by habitat conditions. This study describes the space-temporary nutritional changes in this commercially important species. With this aim, the variations in the nutritional condition (K) of lobsters from four zones (1, 2, 4 and 5) in the Gulf of Batabanó, Cuba, were determined. For this, the weight/length ratio (K=Pt/Lt) was calculated using animals captured in 1981 and 2010. The nutritional condition between areas and sexes, and years and sexes, was contrasted by a bifactorial ANOVA, and the overall length and weight of lobsters were compared using a t-Test for independent samples and unifactorial ANOVA. It was found that the nutritional condition was significantly greater in males than in females. In addition, significant variations between zones were detected for both years. Nutritional condition of lobsters from Zone five was the highest for 1981, while it was Zone two for 2010. Lobsters nutritional state showed significant variations between years, being greater in 1981 (2.34 +/- 0.84g/mm) than in 2010 (1.96 +/- 0.49g/mm). The inter-zones variations as well as the inter-annual ones seem to be related to the reported variations of the bottom type and the vegetation cover. Seasonal variations in the abundance and distribution of benthic organisms, that constitute food for lobsters, could also be influencing. The differences between sexes, however, were assumed as a consequence of the methodology used and the sexual dimorphism of the species. Due to other K estimation methods, that do not include morphometric measurements, these differences were not detected. We suggested that the P. argus nutritional condition is a good estimator of the habitat condition. Besides, according to the applied K estimation methodology, it was found that different groups of lobsters that have resemblant nutritional condition, did not necessarily observe similarities in the overall mean length or weight, so they could exist under different habitat conditions.

Genetic Variability and Population Structure of Disanthus cercidifolius subsp. longipes (Hamamelidaceae) Based on AFLP Analysis

PubMed Central

Yu, Yi; Fan, Qiang; Shen, Rujiang; Guo, Wei; Jin, Jianhua; Cui, Dafang; Liao, Wenbo

2014-01-01

Disanthus cercidifolius subsp. longipes is an endangered species in China. Genetic diversity and structure analysis of this species was investigated using amplified fragments length polymorphism (AFLP) fingerprinting. Nei's gene diversity ranged from 0.1290 to 0.1394. The AMOVA indicated that 75.06% of variation was distributed within populations, while the between-group component 5.04% was smaller than the between populations-within-group component 19.90%. Significant genetic differentiation was detected between populations. Genetic and geographical distances were not correlated. PCA and genetic structure analysis showed that populations from East China were together with those of the Nanling Range. These patterns of genetic diversity and levels of genetic variation may be the result of D. c. subsp. longipes restricted to several isolated habitats and “excess flowers production, but little fruit set”. It is necessary to protect all existing populations of D. c. subsp. longipes in order to preserve as much genetic variation as possible. PMID:25250583

Exploring gravitational lensing model variations in the Frontier Fields galaxy clusters

NASA Astrophysics Data System (ADS)

Harris James, Nicholas John; Raney, Catie; Brennan, Sean; Keeton, Charles

2018-01-01

Multiple groups have been working on modeling the mass distributions of the six lensing galaxy clusters in the Hubble Space Telescope Frontier Fields data set. The magnification maps produced from these mass models will be important for the future study of the lensed background galaxies, but there exists significant variation in the different groups’ models and magnification maps. We explore the use of two-dimensional histograms as a tool for visualizing these magnification map variations. Using a number of simple, one- or two-halo singular isothermal sphere models, we explore the features that are produced in 2D histogram model comparisons when parameters such as halo mass, ellipticity, and location are allowed to vary. Our analysis demonstrates the potential of 2D histograms as a means of observing the full range of differences between the Frontier Fields groups’ models.This work has been supported by funding from National Science Foundation grants PHY-1560077 and AST-1211385, and from the Space Telescope Science Institute.

Genetic Variations in Bionomics of Culex quinquefasciatus (Diptera: Culicidae) Mosquito Population in Minna, North Central Nigeria

PubMed Central

Ukubuiwe, Azubuike C.; Olayemi, Israel K.; Jibrin, Aisha I.

2016-01-01

The need to have an improved knowledge on the bioecology of Culex quinquefasciatus, a prerequisite in the development of cost-effective control strategies, has informed the present preliminary investigation to put in better perspective variations that exist in the egg rafts of the species. Freshly laid egg rafts were collected and incubated at ambient temperature in well-labeled plastic trays. The results showed overall inconsistency in all indices monitored for the egg rafts. Generally, survivorship was high for the species. All immature stage and adult parameters measured varied significantly among the egg rafts and between/within sexes of the species. Therefore, this study suggests the presence of inherent variation in the bionomics of egg rafts of C. quinquefasciatus, probably influenced by the environment and hence underscores the need for additional studies to further elucidate the roles of genetics and environment in vectorial competence of the species, in order to develop robust sustainable mosquito vector control protocols. PMID:27013900

EqualChance: Addressing Intra-set Write Variation to Increase Lifetime of Non-volatile Caches

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

Mittal, Sparsh; Vetter, Jeffrey S

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 withinmore » 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.« less

Regional variations in the management of testicular or ovotesticular disorders of sex development.

PubMed

Josso, N; Audi, L; Shaw, G

2011-01-01

Disorders of sex development arise in parts of the world with different socio-economic and cultural characteristics. We wished to determine the regional variations in the management of these conditions. A questionnaire was e-mailed to the 650 members of the European Society for Paediatric Endocrinology (ESPE), an international society with a mainly European membership but which also includes professionals from other continents. Results were subjected to statistical analysis. A total of 62 answers were received, a satisfactory rate given that not all members are involved in this issue. Results show statistically significant regional differences for available diagnostic resources, age of the patient at gender assignment, parameters considered important for gender assignment, and timing of discussion of various issues with parents and patient. The regional variations exist not only between different continents, as already demonstrated by others, but also between Northern, Latin and Eastern European countries. This suggests that 'one-fits-all' guidelines for management are not appropriate. Copyright © 2011 S. Karger AG, Basel.

Meteorological limits on the growth and development of screwworm populations

NASA Technical Reports Server (NTRS)

Phinney, D. E.; Arp, G. K.

1978-01-01

A program to evaluate the use of remotely sensed data as an additional tool in existing and projected efforts to eradicate the screwworm began in 1973. Estimating weather conditions by use of remotely sensed data was part of the study. Next, the effect of weather on screwworm populations was modeled. A significant portion of the variation in screwworm population growth and development has been traced to weather-related parameters. This report deals with the salient points of the weather and the screwworm population interaction.

Enhanced Vapor-Phase Diffusion in Porous Media - LDRD Final Report

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

Ho, C.K.; Webb, S.W.

1999-01-01

As part of the Laboratory-Directed Research and Development (LDRD) Program at Sandia National Laboratories, an investigation into the existence of enhanced vapor-phase diffusion (EVD) in porous media has been conducted. A thorough literature review was initially performed across multiple disciplines (soil science and engineering), and based on this review, the existence of EVD was found to be questionable. As a result, modeling and experiments were initiated to investigate the existence of EVD. In this LDRD, the first mechanistic model of EVD was developed which demonstrated the mechanisms responsible for EVD. The first direct measurements of EVD have also been conductedmore » at multiple scales. Measurements have been made at the pore scale, in a two- dimensional network as represented by a fracture aperture, and in a porous medium. Significant enhancement of vapor-phase transport relative to Fickian diffusion was measured in all cases. The modeling and experimental results provide additional mechanisms for EVD beyond those presented by the generally accepted model of Philip and deVries (1957), which required a thermal gradient for EVD to exist. Modeling and experimental results show significant enhancement under isothermal conditions. Application of EVD to vapor transport in the near-surface vadose zone show a significant variation between no enhancement, the model of Philip and deVries, and the present results. Based on this information, the model of Philip and deVries may need to be modified, and additional studies are recommended.« less

Genome Variation Within Triticale in Comparison to its Wheat and Rye Progenitors

USDA-ARS?s Scientific Manuscript database

Genome variation in the intergeneric wheat-rye hybrid triticale (X Triticosecale Wittmack) has been a puzzle to scientists and plant breeders since the first triticale was synthesized. The existence of unexplained genetic variation in triticale as compared to the parents has been a hindrance to bre...

Intraspecific Trait Variation and Coordination: Root and Leaf Economics Spectra in Coffee across Environmental Gradients

PubMed Central

Isaac, Marney E.; Martin, Adam R.; de Melo Virginio Filho, Elias; Rapidel, Bruno; Roupsard, Olivier; Van den Meersche, Karel

2017-01-01

Hypotheses on the existence of a universal “Root Economics Spectrum” (RES) have received arguably the least attention of all trait spectra, despite the key role root trait variation plays in resource acquisition potential. There is growing interest in quantifying intraspecific trait variation (ITV) in plants, but there are few studies evaluating (i) the existence of an intraspecific RES within a plant species, or (ii) how a RES may be coordinated with other trait spectra within species, such as a leaf economics spectrum (LES). Using Coffea arabica (Rubiaceae) as a model species, we measured seven morphological and chemical traits of intact lateral roots, which were paired with information on four key LES traits. Field collections were completed across four nested levels of biological organization. The intraspecific trait coefficient of variation (cv) ranged from 25 to 87% with root diameter and specific root tip density showing the lowest and highest cv, respectively. Between 27 and 68% of root ITV was explained by site identity alone for five of the seven traits measured. A single principal component explained 56.2% of root trait covariation, with plants falling along a RES from resource acquiring to conserving traits. Multiple factor analysis revealed significant orthogonal relationships between root and leaf spectra. RES traits were strongly orthogonal with respect to LES traits, suggesting these traits vary independently from one another in response to environmental cues. This study provides among the first evidence that plants from the same species differentiate from one another along an intraspecific RES. We find that in one of the world’s most widely cultivated crops, an intraspecific RES is orthogonal to an intraspecific LES, indicating that above and belowground responses of plants to managed (or natural) environmental gradients are likely to occur independently from one another. PMID:28747919

Intraspecific Trait Variation and Coordination: Root and Leaf Economics Spectra in Coffee across Environmental Gradients.

PubMed

Isaac, Marney E; Martin, Adam R; de Melo Virginio Filho, Elias; Rapidel, Bruno; Roupsard, Olivier; Van den Meersche, Karel

2017-01-01

Hypotheses on the existence of a universal "Root Economics Spectrum" (RES) have received arguably the least attention of all trait spectra, despite the key role root trait variation plays in resource acquisition potential. There is growing interest in quantifying intraspecific trait variation (ITV) in plants, but there are few studies evaluating (i) the existence of an intraspecific RES within a plant species, or (ii) how a RES may be coordinated with other trait spectra within species, such as a leaf economics spectrum (LES). Using Coffea arabica (Rubiaceae) as a model species, we measured seven morphological and chemical traits of intact lateral roots, which were paired with information on four key LES traits. Field collections were completed across four nested levels of biological organization. The intraspecific trait coefficient of variation (cv) ranged from 25 to 87% with root diameter and specific root tip density showing the lowest and highest cv, respectively. Between 27 and 68% of root ITV was explained by site identity alone for five of the seven traits measured. A single principal component explained 56.2% of root trait covariation, with plants falling along a RES from resource acquiring to conserving traits. Multiple factor analysis revealed significant orthogonal relationships between root and leaf spectra. RES traits were strongly orthogonal with respect to LES traits, suggesting these traits vary independently from one another in response to environmental cues. This study provides among the first evidence that plants from the same species differentiate from one another along an intraspecific RES. We find that in one of the world's most widely cultivated crops, an intraspecific RES is orthogonal to an intraspecific LES, indicating that above and belowground responses of plants to managed (or natural) environmental gradients are likely to occur independently from one another.

Excess congenital non-synonymous variation in leukemia-associated genes in MLL− infant leukemia: a Children's Oncology Group report

PubMed Central

Valentine, M C; Linabery, A M; Chasnoff, S; Hughes, A E O; Mallaney, C; Sanchez, N; Giacalone, J; Heerema, N A; Hilden, J M; Spector, L G; Ross, J A; Druley, T E

2014-01-01

Infant leukemia (IL) is a rare sporadic cancer with a grim prognosis. Although most cases are accompanied by MLL rearrangements and harbor very few somatic mutations, less is known about the genetics of the cases without MLL translocations. We performed the largest exome-sequencing study to date on matched non-cancer DNA from pairs of mothers and IL patients to characterize congenital variation that may contribute to early leukemogenesis. Using the COSMIC database to define acute leukemia-associated candidate genes, we find a significant enrichment of rare, potentially functional congenital variation in IL patients compared with randomly selected genes within the same patients and unaffected pediatric controls. IL acute myeloid leukemia (AML) patients had more overall variation than IL acute lymphocytic leukemia (ALL) patients, but less of that variation was inherited from mothers. Of our candidate genes, we found that MLL3 was a compound heterozygote in every infant who developed AML and 50% of infants who developed ALL. These data suggest a model by which known genetic mechanisms for leukemogenesis could be disrupted without an abundance of somatic mutation or chromosomal rearrangements. This model would be consistent with existing models for the establishment of leukemia clones in utero and the high rate of IL concordance in monozygotic twins. PMID:24301523

Variation in payments for spine surgery episodes of care: implications for episode-based bundled payment.

PubMed

Kahn, Elyne N; Ellimoottil, Chandy; Dupree, James M; Park, Paul; Ryan, Andrew M

2018-05-25

OBJECTIVE Spine surgery is expensive and marked by high variation across regions and providers. Bundled payments have potential to reduce unwarranted spending associated with spine surgery. This study is a cross-sectional analysis of commercial and Medicare claims data from January 2012 through March 2015 in the state of Michigan. The objective was to quantify variation in payments for spine surgery in adult patients, document sources of variation, and determine influence of patient-level, surgeon-level, and hospital-level factors. METHODS Hierarchical regression models were used to analyze contributions of patient-level covariates and influence of individual surgeons and hospitals. The primary outcome was price-standardized 90-day episode payments. Intraclass correlation coefficients-measures of variability accounted for by each level of a hierarchical model-were used to quantify sources of spending variation. RESULTS The authors analyzed 17,436 spine surgery episodes performed by 195 surgeons at 50 hospitals. Mean price-standardized 90-day episode payments in the highest spending quintile exceeded mean payments for episodes in the lowest cost quintile by $42,953 (p < 0.001). Facility payments for index admission and post-discharge payments were the greatest contributors to overall variation: 39.4% and 32.5%, respectively. After accounting for patient-level covariates, the remaining hospital-level and surgeon-level effects accounted for 2.0% (95% CI 1.1%-3.8%) and 4.0% (95% CI 2.9%-5.6%) of total variation, respectively. CONCLUSIONS Significant variation exists in total episode payments for spine surgery, driven mostly by variation in post-discharge and facility payments. Hospital and surgeon effects account for relatively little of the observed variation.

Physical-level synthesis for digital lab-on-a-chip considering variation, contamination, and defect.

PubMed

Liao, Chen; Hu, Shiyan

2014-03-01

Microfluidic lab-on-a-chips have been widely utilized in biochemical analysis and human health studies due to high detection accuracy, high timing efficiency, and low cost. The increasing design complexity of lab-on-a-chips necessitates the computer-aided design (CAD) methodology in contrast to the classical manual design methodology. A key part in lab-on-a-chip CAD is physical-level synthesis. It includes the lab-on-a-chip placement and routing, where placement is to determine the physical location and the starting time of each operation and routing is to transport each droplet from the source to the destination. In the lab-on-a-chip design, variation, contamination, and defect need to be considered. This work designs a physical-level synthesis flow which simultaneously considers variation, contamination, and defect of the lab-on-a-chip design. It proposes a maze routing based, variation, contamination, and defect aware droplet routing technique, which is seamlessly integrated into an existing placement technique. The proposed technique improves the placement solution for routing and achieves the placement and routing co-optimization to handle variation, contamination, and defect. The simulation results demonstrate that our technique does not use any defective/contaminated grids, while the technique without considering contamination and defect uses 17.0% of the defective/contaminated grids on average. In addition, our routing variation aware technique significantly improves the average routing yield by 51.2% with only 3.5% increase in completion time compared to a routing variation unaware technique.

Regional Differences in Case Mix and Peri-operative Outcome After Elective Abdominal Aortic Aneurysm Repair in the Vascunet Database.

PubMed

Mani, K; Venermo, M; Beiles, B; Menyhei, G; Altreuther, M; Loftus, I; Björck, M

2015-06-01

National differences exist in the outcome of elective abdominal aortic aneurysm (AAA) repair. The role of case mix variation was assessed based on an international vascular registry collaboration. All elective AAA repairs with aneurysm size data in the Vascunet database in the period 2005-09 were included. AAA size and peri-operative outcome (crude and age adjusted mortality) were analysed overall and in risk cohorts, as well as per country. Glasgow Aneurysm Score (GAS) was calculated as risk score, and patients were stratified in three equal sized risk cohorts based on GAS. Predictors of peri-operative mortality were analysed with multiple regression. Missing data were handled with multiple imputation. Patients from Australia, Finland, Hungary, Norway, Sweden and the UK (n = 5,895) were analysed; mean age was 72.7 years and 54% had endovascular repair (EVAR). There were significant variations in GAS (lowest = Finland [75.7], highest = UK [79.4], p for comparison of all regions < .001), proportion of AAA < 5.5 cm (lowest = UK [6.4%], highest = Hungary [29.0%]; p < .001), proportion undergoing EVAR (lowest = Finland [10.1%], highest = Australia [58.9%]; p < .001), crude mortality (lowest = Norway [2.0%], highest = Finland [5.0%]; p = .006), and age adjusted mortality (lowest = Norway [2.5%], highest = Finland [6.0%]; p = .048). Both aneurysm size and peri-operative mortality were highest among patients with a GAS >82. Of those with a GAS >82, 8.4% of men and 20.8% of women had an AAA <5.5 cm. Important regional differences exist in case selection for elective AAA repair, including variations in AAA size and patient risk profile. These differences partly explain the variations in peri-operative mortality. Further audit is warranted to assess the underlying reasons for the regional variation in case-mix. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop

PubMed Central

2011-01-01

Background Envenomation by crotaline snakes (rattlesnake, cottonmouth, copperhead) is a complex, potentially lethal condition affecting thousands of people in the United States each year. Treatment of crotaline envenomation is not standardized, and significant variation in practice exists. Methods A geographically diverse panel of experts was convened for the purpose of deriving an evidence-informed unified treatment algorithm. Research staff analyzed the extant medical literature and performed targeted analyses of existing databases to inform specific clinical decisions. A trained external facilitator used modified Delphi and structured consensus methodology to achieve consensus on the final treatment algorithm. Results A unified treatment algorithm was produced and endorsed by all nine expert panel members. This algorithm provides guidance about clinical and laboratory observations, indications for and dosing of antivenom, adjunctive therapies, post-stabilization care, and management of complications from envenomation and therapy. Conclusions Clinical manifestations and ideal treatment of crotaline snakebite differ greatly, and can result in severe complications. Using a modified Delphi method, we provide evidence-informed treatment guidelines in an attempt to reduce variation in care and possibly improve clinical outcomes. PMID:21291549

Long-Period Tidal Variations in the Length of Day

NASA Technical Reports Server (NTRS)

Ray, Richard D.; Erofeeva, Svetlana Y.

2014-01-01

A new model of long-period tidal variations in length of day is developed. The model comprises 80 spectral lines with periods between 18.6 years and 4.7 days, and it consistently includes effects of mantle anelasticity and dynamic ocean tides for all lines. The anelastic properties followWahr and Bergen; experimental confirmation for their results now exists at the fortnightly period, but there remains uncertainty when extrapolating to the longest periods. The ocean modeling builds on recent work with the fortnightly constituent, which suggests that oceanic tidal angular momentum can be reliably predicted at these periods without data assimilation. This is a critical property when modeling most long-period tides, for which little observational data exist. Dynamic ocean effects are quite pronounced at shortest periods as out-of-phase rotation components become nearly as large as in-phase components. The model is tested against a 20 year time series of space geodetic measurements of length of day. The current international standard model is shown to leave significant residual tidal energy, and the new model is found to mostly eliminate that energy, with especially large variance reduction for constituents Sa, Ssa, Mf, and Mt.

Temporal Variation of the Rotation of the Solar Mean Magnetic Field

NASA Astrophysics Data System (ADS)

Xie, J. L.; Shi, X. J.; Xu, J. C.

2017-04-01

Based on continuous wavelet transformation analysis, the daily solar mean magnetic field (SMMF) from 1975 May 16 to 2014 July 31 is analyzed to reveal its rotational behavior. Both the recurrent plot in Bartels form and the continuous wavelet transformation analysis show the existence of rotational modulation in the variation of the daily SMMF. The dependence of the rotational cycle lengths on solar cycle phase is also studied, which indicates that the yearly mean rotational cycle lengths generally seem to be longer during the rising phase of solar cycles and shorter during the declining phase. The mean rotational cycle length for the rising phase of all of the solar cycles in the considered time is 28.28 ± 0.67 days, while for the declining phase it is 27.32 ± 0.64 days. The difference of the mean rotational cycle lengths between the rising phase and the declining phase is 0.96 days. The periodicity analysis, through the use of an auto-correlation function, indicates that the rotational cycle lengths have a significant period of about 10.1 years. Furthermore, the cross-correlation analysis indicates that there exists a phase difference between the rotational cycle lengths and solar activity.

Comparing the Reproductive Success of Yakima River Hatchery- and Wild-Origin Spring Chinook; Yakima/Klickitat Fisheries Project Monitoring and Evaluation, 2005-2006 Annual Report.

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

Schroder, S.L.; Pearsons, T.N.; Knudsen, C.M.

Reproductive success in wild- and first generation hatchery-origin spring Chinook males was examined by allowing the fish to compete for spawning opportunities in two sections of an observation stream. Behavioral observations were used to characterize the frequency of aggression and courting activities. Microsatellite DNA from each male and fry collected from the observation stream were used in pedigree analyses to estimate reproductive success. The coefficient of variation in male reproductive success equaled 116 and 86% in the two populations. No differences were detected in reproductive success due to hatchery or wild origin. Nor were any behavioral differences found between hatcherymore » and wild males. Although statistical power was low due to intrinsic variation a great deal of overlap existed in the reproductive success values of hatchery and wild males. Significant disparities existed among the males on their ability to produce offspring. Males achieving high reproductive success mated with numerous females, were socially dominant, aggressive, and tended to stay in localized areas, courting and spawning with females that were adjacent to one another.« less

Racial Variation in the Use of Life-Sustaining Treatments among Patients Who Die After Major Elective Surgery

PubMed Central

Hernandez, Roland A.; Hevelone, Nathanael D.; Lopez, Lenny; Finlayson, Samuel R.G.; Chittenden, Eva; Cooper, Zara

2015-01-01

Background Although various studies have documented increased Life-Sustaining Treatments (LST) among racial minorities in medical patients, whether similar disparities exist in surgical patients is unknown. Methods Retrospective cohort study using the Nationwide Inpatient Sample (2006–2011) examining patients >39 years who died following elective colectomy. Primary predictor variable was race and main outcome was use of LST. Results In univariate analysis, significant differences existed in use of CPR (Black-35.9%, Hispanic-29.0%, Other-24.5%, White-11.7%, p = 0.002) and re-intubation (Hispanic-75.0%, Other-69.0%, Black-52.3%, White-45.2%, p = 0.01). In multivariate analysis, Black (OR3.67, p=0.01) and Hispanic (4.21, p=0.03) patients were more likely to have undergone CPR, and Hispanic patients (4.24, p=0.01) were more likely to have been re-intubated (reference: White). Conclusions Blacks and Hispanics had increased odds of experiencing CPR, and Hispanics were more likely to have been re-intubated before death following a major elective operation. These variations may imply worse quality of death and increased associated costs. PMID:25465749

Novel Fourier-based iterative reconstruction for sparse fan projection using alternating direction total variation minimization

NASA Astrophysics Data System (ADS)

Zhao, Jin; Han-Ming, Zhang; Bin, Yan; Lei, Li; Lin-Yuan, Wang; Ai-Long, Cai

2016-03-01

Sparse-view x-ray computed tomography (CT) imaging is an interesting topic in CT field and can efficiently decrease radiation dose. Compared with spatial reconstruction, a Fourier-based algorithm has advantages in reconstruction speed and memory usage. A novel Fourier-based iterative reconstruction technique that utilizes non-uniform fast Fourier transform (NUFFT) is presented in this work along with advanced total variation (TV) regularization for a fan sparse-view CT. The proposition of a selective matrix contributes to improve reconstruction quality. The new method employs the NUFFT and its adjoin to iterate back and forth between the Fourier and image space. The performance of the proposed algorithm is demonstrated through a series of digital simulations and experimental phantom studies. Results of the proposed algorithm are compared with those of existing TV-regularized techniques based on compressed sensing method, as well as basic algebraic reconstruction technique. Compared with the existing TV-regularized techniques, the proposed Fourier-based technique significantly improves convergence rate and reduces memory allocation, respectively. Projected supported by the National High Technology Research and Development Program of China (Grant No. 2012AA011603) and the National Natural Science Foundation of China (Grant No. 61372172).

Can skull form predict the shape of the temporomandibular joint? A study using geometric morphometrics on the skulls of wolves and domestic dogs.

PubMed

Curth, Stefan; Fischer, Martin S; Kupczik, Kornelius

2017-11-01

The temporomandibular joint (TMJ) conducts and restrains masticatory movements between the mammalian cranium and the mandible. Through this functional integration, TMJ morphology in wild mammals is strongly correlated with diet, resulting in a wide range of TMJ variations. However, in artificially selected and closely related domestic dogs, dietary specialisations between breeds can be ruled out as a diversifying factor although they display an enormous variation in TMJ morphology. This raises the question of the origin of this variation. Here we hypothesise that, even in the face of reduced functional demands, TMJ shape in dogs can be predicted by skull form; i.e. that the TMJ is still highly integrated in the dog skull. If true, TMJ variation in the dog would be a plain by-product of the enormous cranial variation in dogs and its genetic causes. We addressed this hypothesis using geometric morphometry on a data set of 214 dog and 60 wolf skulls. We digitized 53 three-dimensional landmarks of the skull and the TMJ on CT-based segmentations and compared (1) the variation between domestic dog and wolf TMJs (via principal component analysis) and (2) the pattern of covariation of skull size, flexion and rostrum length with TMJ shape (via regression of centroid size on shape and partial least squares analyses). We show that the TMJ in domestic dogs is significantly more diverse than in wolves: its shape covaries significantly with skull size, flexion and rostrum proportions in patterns which resemble those observed in primates. Similar patterns in canids, which are carnivorous, and primates, which are mostly frugivorous imply the existence of basic TMJ integration patterns which are independent of dietary adaptations. However, only limited amounts of TMJ variation in dogs can be explained by simple covariation with overall skull geometry. This implies that the final TMJ shape is gained partially independently of the rest of the skull. Copyright © 2017 Elsevier GmbH. All rights reserved.

Efficient genotype compression and analysis of large genetic variation datasets

PubMed Central

Layer, Ryan M.; Kindlon, Neil; Karczewski, Konrad J.; Quinlan, Aaron R.

2015-01-01

Genotype Query Tools (GQT) is a new indexing strategy that expedites analyses of genome variation datasets in VCF format based on sample genotypes, phenotypes and relationships. GQT’s compressed genotype index minimizes decompression for analysis, and performance relative to existing methods improves with cohort size. We show substantial (up to 443 fold) performance gains over existing methods and demonstrate GQT’s utility for exploring massive datasets involving thousands to millions of genomes. PMID:26550772

Study of weak solutions for parabolic variational inequalities with nonstandard growth conditions.

PubMed

Dong, Yan

2018-01-01

In this paper, we study the degenerate parabolic variational inequality problem in a bounded domain. First, the weak solutions of the variational inequality are defined. Second, the existence and uniqueness of the solutions in the weak sense are proved by using the penalty method and the reduction method.

Variational formulation for Black-Scholes equations in stochastic volatility models

NASA Astrophysics Data System (ADS)

Gyulov, Tihomir B.; Valkov, Radoslav L.

2012-11-01

In this note we prove existence and uniqueness of weak solutions to a boundary value problem arising from stochastic volatility models in financial mathematics. Our settings are variational in weighted Sobolev spaces. Nevertheless, as it will become apparent our variational formulation agrees well with the stochastic part of the problem.

Parents or predators: Examining intraseasonal variation in nest survival for migratory passerine

Treesearch

Robin Hirsch-Jacobson; W. Andrew Cox; Emily E. Tewes; Frank R., III Thompson; John Faaborg

2012-01-01

For birds, risk of nest predation can vary within a breeding season, but few data exist that explain why such variation occurs. We investigated intraseasonal variation of nest survival of the Acadian Flycatcher (Empidonax virescens) in Midwestern forests and tested whether four of the adults' reproductive strategies (clutch size, nest...

Factors influencing the atmospheric concentrations of PCBs at an abandoned e-waste recycling site in South China.

PubMed

Wang, Yan; Wu, Xiaowei; Hou, Minmin; Zhao, Hongxia; Chen, Ruize; Luo, Chunling; Zhang, Gan

2017-02-01

The diurnal atmospheric concentrations of polychlorinated biphenyls (PCBs) were investigated at an abandoned e-waste recycling site in South China during winter and summer. Total PCB concentrations during winter and summer were 27.6-212 and 368-1704pg/m 3 in the particulate phase and 270-697 and 3000-15,500pg/m 3 in the gaseous phase, respectively. Both gaseous and particulate PCB concentrations and compositions exhibited significant difference between winter and summer samples, but no diurnal variations during the measurement period. The correlation analysis between PCB concentrations and meteorological conditions, including atmospheric temperature, humidity, and mixing layer height, suggested that the seasonal variability of atmospheric PCB concentrations was strongly temperature-dependent, while the diurnal variability was probably source-dependent. The temperature-driven variations can also be proved by the significant linear correlation between ln P and 1/T in the Clausius-Clapeyron plot. Although government has implemented controls to reduce e-waste pollution, both the relatively high concentrations of PCBs and the diurnal variation in the air suggested that emissions from occasional e-waste recycling activities may still exist in this recycling area. These results underline the importance of continuing e-waste recycling site management long after abandonment. Copyright © 2016 Elsevier B.V. All rights reserved.

Transition energies and polarizabilities of hydrogen like ions in plasma

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

Das, Madhusmita

2012-09-15

Effect of plasma screening on various properties like transition energy, polarizability (dipole and quadrupole), etc. of hydrogen like ions is studied. The bound and free state wave functions and transition matrix elements are obtained by numerically integrating the radial Schrodinger equation for appropriate plasma potential. We have used adaptive step size controlled Runge-Kutta method to perform the numerical integration. Debye-Huckel potential is used to investigate the variation in transition lines and polarizabilities (dipole and quadrupole) with increasing plasma screening. For a strongly coupled plasma, ion sphere potential is used to show the variation in excitation energy with decreasing ion spheremore » radius. It is observed that plasma screening sets in phenomena like continuum lowering and pressure ionization, which are unique to ions in plasma. Of particular interest is the blue (red) shift in transitions conserving (non-conserving) principal quantum number. The plasma environment also affects the dipole and quadrupole polarizability of ions in a significant manner. The bound state contribution to polarizabilities decreases with increase in plasma density whereas the continuum contribution is significantly enhanced. This is a result of variation in the behavior of bound and continuum state wave functions in the presence of plasma. We have compared the results with existing theoretical and experimental data wherever present.« less

Impact of Material and Architecture Model Parameters on the Failure of Woven Ceramic Matrix Composites (CMCs) via the Multiscale Generalized Method of Cells

NASA Technical Reports Server (NTRS)

Liu, Kuang C.; Arnold, Steven M.

2011-01-01

It is well known that failure of a material is a locally driven event. In the case of ceramic matrix composites (CMCs), significant variations in the microstructure of the composite exist and their significance on both deformation and life response need to be assessed. Examples of these variations include changes in the fiber tow shape, tow shifting/nesting and voids within and between tows. In the present work, the effects of many of these architectural parameters and material scatter of woven ceramic composite properties at the macroscale (woven RUC) will be studied to assess their sensitivity. The recently developed Multiscale Generalized Method of Cells methodology is used to determine the overall deformation response, proportional elastic limit (first matrix cracking), and failure under tensile loading conditions. The macroscale responses investigated illustrate the effect of architectural and material parameters on a single RUC representing a five harness satin weave fabric. Results shows that the most critical architectural parameter is weave void shape and content with other parameters being less in severity. Variation of the matrix material properties was also studied to illustrate the influence of the material variability on the overall features of the composite stress-strain response.

Assigning Robust Default Values in Building Performance Simulation Software for Improved Decision-Making in the Initial Stages of Building Design.

PubMed

Hiyama, Kyosuke

2015-01-01

Applying data mining techniques on a database of BIM models could provide valuable insights in key design patterns implicitly present in these BIM models. The architectural designer would then be able to use previous data from existing building projects as default values in building performance simulation software for the early phases of building design. The author has proposed the method to minimize the magnitude of the variation in these default values in subsequent design stages. This approach maintains the accuracy of the simulation results in the initial stages of building design. In this study, a more convincing argument is presented to demonstrate the significance of the new method. The variation in the ideal default values for different building design conditions is assessed first. Next, the influence of each condition on these variations is investigated. The space depth is found to have a large impact on the ideal default value of the window to wall ratio. In addition, the presence or absence of lighting control and natural ventilation has a significant influence on the ideal default value. These effects can be used to identify the types of building conditions that should be considered to determine the ideal default values.

Assigning Robust Default Values in Building Performance Simulation Software for Improved Decision-Making in the Initial Stages of Building Design

PubMed Central

2015-01-01

Applying data mining techniques on a database of BIM models could provide valuable insights in key design patterns implicitly present in these BIM models. The architectural designer would then be able to use previous data from existing building projects as default values in building performance simulation software for the early phases of building design. The author has proposed the method to minimize the magnitude of the variation in these default values in subsequent design stages. This approach maintains the accuracy of the simulation results in the initial stages of building design. In this study, a more convincing argument is presented to demonstrate the significance of the new method. The variation in the ideal default values for different building design conditions is assessed first. Next, the influence of each condition on these variations is investigated. The space depth is found to have a large impact on the ideal default value of the window to wall ratio. In addition, the presence or absence of lighting control and natural ventilation has a significant influence on the ideal default value. These effects can be used to identify the types of building conditions that should be considered to determine the ideal default values. PMID:26090512

Identification and ranking of environmental threats with ecosystem vulnerability distributions.

PubMed

Zijp, Michiel C; Huijbregts, Mark A J; Schipper, Aafke M; Mulder, Christian; Posthuma, Leo

2017-08-24

Responses of ecosystems to human-induced stress vary in space and time, because both stressors and ecosystem vulnerabilities vary in space and time. Presently, ecosystem impact assessments mainly take into account variation in stressors, without considering variation in ecosystem vulnerability. We developed a method to address ecosystem vulnerability variation by quantifying ecosystem vulnerability distributions (EVDs) based on monitoring data of local species compositions and environmental conditions. The method incorporates spatial variation of both abiotic and biotic variables to quantify variation in responses among species and ecosystems. We show that EVDs can be derived based on a selection of locations, existing monitoring data and a selected impact boundary, and can be used in stressor identification and ranking for a region. A case study on Ohio's freshwater ecosystems, with freshwater fish as target species group, showed that physical habitat impairment and nutrient loads ranked highest as current stressors, with species losses higher than 5% for at least 6% of the locations. EVDs complement existing approaches of stressor assessment and management, which typically account only for variability in stressors, by accounting for variation in the vulnerability of the responding ecosystems.

Quantifying Geographic Variation in Health Care Outcomes in the United States before and after Risk-Adjustment.

PubMed

Rosenberg, Barry L; Kellar, Joshua A; Labno, Anna; Matheson, David H M; Ringel, Michael; VonAchen, Paige; Lesser, Richard I; Li, Yue; Dimick, Justin B; Gawande, Atul A; Larsson, Stefan H; Moses, Hamilton

2016-01-01

Despite numerous studies of geographic variation in healthcare cost and utilization at the local, regional, and state levels across the U.S., a comprehensive characterization of geographic variation in outcomes has not been published. Our objective was to quantify variation in US health outcomes in an all-payer population before and after risk-adjustment. We used information from 16 independent data sources, including 22 million all-payer inpatient admissions from the Healthcare Cost and Utilization Project (which covers regions where 50% of the U.S. population lives) to analyze 24 inpatient mortality, inpatient safety, and prevention outcomes. We compared outcome variation at state, hospital referral region, hospital service area, county, and hospital levels. Risk-adjusted outcomes were calculated after adjusting for population factors, co-morbidities, and health system factors. Even after risk-adjustment, there exists large geographical variation in outcomes. The variation in healthcare outcomes exceeds the well publicized variation in US healthcare costs. On average, we observed a 2.1-fold difference in risk-adjusted mortality outcomes between top- and bottom-decile hospitals. For example, we observed a 2.3-fold difference for risk-adjusted acute myocardial infarction inpatient mortality. On average a 10.2-fold difference in risk-adjusted patient safety outcomes exists between top and bottom-decile hospitals, including an 18.3-fold difference for risk-adjusted Central Venous Catheter Bloodstream Infection rates. A 3.0-fold difference in prevention outcomes exists between top- and bottom-decile counties on average; including a 2.2-fold difference for risk-adjusted congestive heart failure admission rates. The population, co-morbidity, and health system factors accounted for a range of R2 between 18-64% of variability in mortality outcomes, 3-39% of variability in patient safety outcomes, and 22-70% of variability in prevention outcomes. The amount of variability in health outcomes in the U.S. is large even after accounting for differences in population, co-morbidities, and health system factors. These findings suggest that: 1) additional examination of regional and local variation in risk-adjusted outcomes should be a priority; 2) assumptions of uniform hospital quality that underpin rationale for policy choices (such as narrow insurance networks or antitrust enforcement) should be challenged; and 3) there exists substantial opportunity for outcomes improvement in the US healthcare system.

Intraspecific variation in egg size and egg composition in birds: effects on offspring fitness.

PubMed

Williams, T D

1994-02-01

1. There is little unequivocal evidence to date in support of a positive relationship between egg size and offspring fitness in birds. Although 40 studies (of 34 species) have considered the effect of variation in egg size on chick growth and/or survival up to fledgling only 12 studies have controlled for other characters potentially correlated both with egg size and offspring fitness. Of these only two have reported a significant residual effect of egg size on chick growth (in the roseate tern and European blackbird) and three a residual effect on chick survival (all in seabirds: common tern, lesser black-backed gull and kittiwake). 2. More consistent evidence exists, though from fewer studies, for a positive relationship between egg size and offspring fitness early in the chick-rearing period; chick growth and chick survival being dependent on egg size in 8 of 10 studies and 4 of 5 studies respectively. It is suggested that the most important effect of variation in egg size might be in determining the probability of offspring survival in the first few days after hatching. 3. Egg size explains on average 66% of the variation in chick mass at hatching (n = 35 studies) but only 30% of the variation in chick body size (n = 18). When effects of hatching body size are controlled for chick mass remains significantly correlated with egg size, though the reverse is not true. This supports the hypothesis that large eggs give rise to heavier chicks at hatching, i.e., chicks with more nutrient (yolk) reserves, rather than structurally larger chicks. 4. Egg composition increased isometrically with increasing egg size in about half the studies so far reported (n equals approximately 20). However, in seabirds, and some passerines, larger eggs contain disproportionately more albumen, whilst in some waterfowl percentage yolk content increases with increasing egg size. Changes in albumen content largely reflect variation in the water content of eggs, but changes in yolk content involve variation in lipid content, and therefore in egg 'quality.' The adaptive significance of variation in egg composition is considered; females may adjust egg composition facultatively to maximise the benefits to their offspring of increased reproductive investment. 5. Considerations for future research are discussed with particular emphasis on experimental studies and the application of new techniques.

Spatial and temporal variation of correlation between the Arctic total ozone and atmospheric temperature

NASA Astrophysics Data System (ADS)

Huang, Fuxiang; Ren, suling; Han, Shuangshuang; Zheng, xiangdong; Deng, xuejiao

2017-04-01

Daily total ozone and atmospheric temperature profile data in 2015 from the AIRS are used to investigate the spatial and temporal variation of the correlation between the Arctic atmospheric ozone and temperature. In the study, 11 lays atmospheric temperature profiles from the troposphere to the stratosphere are investigated. These layer heights are 20, 50, 70, 100, 200, 250, 300, 400, 500, 600 and 700 hPa respectively. The results show that a significant seasonal split exists in the correlation between the Arctic ozone and atmospheric temperature. Figure 1 shows the spatial and temporal variation of the coefficient between the atmospheric ozone and temperature at 50hPa. It can be seen from the figure that an obvious spatiotemporal difference exists in the correlation between the Arctic total ozone and atmospheric temperature in the lower stratosphere. First, the seasonal difference is very remarkable, which is shown as a significant positive correlation in most regions during winter and summer, while no correlation in the majority of regions occurs during spring and autumn, with a weak positive or negative correlation in a small number regions. Second, the spatial differences are also very obvious. The summer maximum correlation coefficient occurs in the Barents Sea and other locations at 0.8 and above, while the winter maximum occurs in the Baffin Bay area at 0.6 to 0.8. However, in a small number of regions, such as the land to the west of the Bering Strait in winter and the Arctic Ocean core area in summer, the correlation coefficients were unable to pass the significance test to show no correlation. At the same time, in spring and autumn, a positive correlation only occurs over a few low-latitude land areas, while over other Arctic areas, weak negative correlation exists. The differences in horizontal position are clearly related to the land-sea distribution, underlying surface characteristics, glacial melting, and other factors. In the troposphere, the ozone and temperature have a strong negative correlation in spring and autumn, while presenting a weak negative correlation or no correlation in winter and summer. Figure 2 shows the spatial and temporal variation of the correlation coefficient between the atmospheric ozone and temperature at 500hPa. From figure 2, it can be seen that in the Arctic troposphere, the atmospheric ozone and tropospheric temperature mainly have a negative correlation. In winter and summer, a weak negative correlation is shown overall, but more than a third of the regions show no correlation. In spring, the negative correlation is the strongest between the ozone and temperature. Especially in Greenland - Queen Elizabeth Islands and southern New Siberian Islands, the correlation is the highest, with a correlation coefficient of -0.9 and above, followed by a negative correlation in autumn. Except for a small number of low-latitude scattered regions with weak correlation, the correlation coefficients of most regions are ranged between -0.5 and -0.7. At 300 hPa near the tropopause, the horizontal distribution and seasonal change of the correlation between the Arctic total ozone and atmospheric temperature are as shown in Fig. 3.At the height near the Arctic tropopause, the atmospheric ozone mainly has no correlation to temperature, especially in winter and summer, when no correlation exists in the majority of regions, while weak positive or negative correlation occurs in a small number of areas. In the majority of regions during spring, a weak negative correlation is shown, while no correlation appears in Western Greenland - Queen Elizabeth Islands. In autumn, most regions show no correlation, while weak negative correlation is presented in Eastern Greenland, Norwegian Sea - Barents Sea, and other locations. From figure 1-3, we can see a significant difference exists from the common law of positive correlation in the lower stratosphere and negative correlation in the troposphere at mid-low latitudes. The Arctic atmospheric ozone has a relation with temperature, showing significant spatial and temporal variation characteristics. In the stratosphere, winter and summer atmospheric temperatures mainly have a positive correlation to ozone. The summer maximum occurs in the Barents Sea to achieve 0.8 and above, while the winter maximum is 0.6 to 0.8 in the Baffin Bay area. In the troposphere, the autumn and spring atmospheric temperatures mainly have a negative correlation to the ozone. The spring correlation coefficient in Greenland to the Queen Elizabeth Islands reaches up to -0.9 and above, while the autumn value is -0.5 to -0.7. At about 300 hPa, the tropopause value is reduced to 0, and further decreased in the troposphere, to show a strong negative correlation. Based on the comprehensive analysis of various influence factors, the possible action mechanism of the spatiotemporal variation pattern of the correlation between the Arctic atmospheric ozone and temperature is discussed based on the seasonal differences of various influence factors. The spatial and temporal variation characteristics of the correlation between the Arctic atmospheric ozone and temperature are determined by the seasonal variation of various influencing factors of the Arctic atmospheric ozone and temperature. These factors include the atmospheric heating effect from the ozone matching with the Arctic sunshine conditions, the influence of dynamic delivery on the ozone and heat, the impact of underlying-surface glacial melting on atmospheric radiation and heat budget, and so on. At different heights in each season, the different effects from all kinds of factors on the ozone and temperature determine the spatiotemporal variation of the correlation between the ozone and temperature.

Short-range phenotypic divergence among genetically distinct parapatric populations of an Australian funnel-web spider.

PubMed

Wong, Mark K L; Woodman, James D; Rowell, David M

2017-07-01

Speciation involves divergence at genetic and phenotypic levels. Where substantial genetic differentiation exists among populations, examining variation in multiple phenotypic characters may elucidate the mechanisms by which divergence and speciation unfold. Previous work on the Australian funnel-web spider Atrax sutherlandi Gray (2010; Records of the Australian Museum 62 , 285-392; Mygalomorphae: Hexathelidae: Atracinae) has revealed a marked genetic structure along a 110-kilometer transect, with six genetically distinct, parapatric populations attributable to past glacial cycles. In the present study, we explore variation in three classes of phenotypic characters (metabolic rate, water loss, and morphological traits) within the context of this phylogeographic structuring. Variation in metabolic and water loss rates shows no detectable association with genetic structure; the little variation observed in these rates may be due to the spiders' behavioral adaptations (i.e., burrowing), which buffer the effects of climatic gradients across the landscape. However, of 17 morphological traits measured, 10 show significant variation among genetic populations, in a disjunct manner that is clearly not latitudinal. Moreover, patterns of variation observed for morphological traits serving different organismic functions (e.g., prey capture, burrowing, and locomotion) are dissimilar. In contrast, a previous study of an ecologically similar sympatric spider with little genetic structure indicated a strong latitudinal response in 10 traits over the same range. The congruence of morphological variation with deep phylogeographic structure in Tallaganda's A. sutherlandi populations, as well as the inconsistent patterns of variation across separate functional traits, suggest that the spiders are likely in early stages of speciation, with parapatric populations independently responding to local selective forces.

Individual variation in cone photoreceptor density in house sparrows: implications for between-individual differences in visual resolution and chromatic contrast.

PubMed

Ensminger, Amanda L; Fernández-Juricic, Esteban

2014-01-01

Between-individual variation has been documented in a wide variety of taxa, especially for behavioral characteristics; however, intra-population variation in sensory systems has not received similar attention in wild animals. We measured a key trait of the visual system, the density of retinal cone photoreceptors, in a wild population of house sparrows (Passer domesticus). We tested whether individuals differed from each other in cone densities given within-individual variation across the retina and across eyes. We further tested whether the existing variation could lead to individual differences in two aspects of perception: visual resolution and chromatic contrast. We found consistent between-individual variation in the densities of all five types of avian cones, involved in chromatic and achromatic vision. Using perceptual modeling, we found that this degree of variation translated into significant between-individual differences in visual resolution and the chromatic contrast of a plumage signal that has been associated with mate choice and agonistic interactions. However, there was no evidence for a relationship between individual visual resolution and chromatic contrast. The implication is that some birds may have the sensory potential to perform "better" in certain visual tasks, but not necessarily in both resolution and contrast simultaneously. Overall, our findings (a) highlight the need to consider multiple individuals when characterizing sensory traits of a species, and (b) provide some mechanistic basis for between-individual variation in different behaviors (i.e., animal personalities) and for testing the predictions of several widely accepted hypotheses (e.g., honest signaling).

Individual Variation in Cone Photoreceptor Density in House Sparrows: Implications for Between-Individual Differences in Visual Resolution and Chromatic Contrast

PubMed Central

Ensminger, Amanda L.; Fernández-Juricic, Esteban

2014-01-01

Between-individual variation has been documented in a wide variety of taxa, especially for behavioral characteristics; however, intra-population variation in sensory systems has not received similar attention in wild animals. We measured a key trait of the visual system, the density of retinal cone photoreceptors, in a wild population of house sparrows (Passer domesticus). We tested whether individuals differed from each other in cone densities given within-individual variation across the retina and across eyes. We further tested whether the existing variation could lead to individual differences in two aspects of perception: visual resolution and chromatic contrast. We found consistent between-individual variation in the densities of all five types of avian cones, involved in chromatic and achromatic vision. Using perceptual modeling, we found that this degree of variation translated into significant between-individual differences in visual resolution and the chromatic contrast of a plumage signal that has been associated with mate choice and agonistic interactions. However, there was no evidence for a relationship between individual visual resolution and chromatic contrast. The implication is that some birds may have the sensory potential to perform “better” in certain visual tasks, but not necessarily in both resolution and contrast simultaneously. Overall, our findings (a) highlight the need to consider multiple individuals when characterizing sensory traits of a species, and (b) provide some mechanistic basis for between-individual variation in different behaviors (i.e., animal personalities) and for testing the predictions of several widely accepted hypotheses (e.g., honest signaling). PMID:25372039

Atlas warping for brain morphometry

NASA Astrophysics Data System (ADS)

Machado, Alexei M. C.; Gee, James C.

1998-06-01

In this work, we describe an automated approach to morphometry based on spatial normalizations of the data, and demonstrate its application to the analysis of gender differences in the human corpus callosum. The purpose is to describe a population by a reduced and representative set of variables, from which a prior model can be constructed. Our approach is rooted in the assumption that individual anatomies can be considered as quantitative variations on a common underlying qualitative plane. We can therefore imagine that a given individual's anatomy is a warped version of some referential anatomy, also known as an atlas. The spatial warps which transform a labeled atlas into anatomic alignment with a population yield immediate knowledge about organ size and shape in the group. Furthermore, variation within the set of spatial warps is directly related to the anatomic variation among the subjects. Specifically, the shape statistics--mean and variance of the mappings--for the population can be calculated in a special basis, and an eigendecomposition of the variance performed to identify the most significant modes of shape variation. The results obtained with the corpus callosum study confirm the existence of substantial anatomical differences between males and females, as reported in previous experimental work.

Ethnic and socioeconomic variation in incidence of congenital heart defects.

PubMed

Knowles, Rachel L; Ridout, Deborah; Crowe, Sonya; Bull, Catherine; Wray, Jo; Tregay, Jenifer; Franklin, Rodney C; Barron, David J; Cunningham, David; Parslow, Roger C; Brown, Katherine L

2017-06-01

Ethnic differences in the birth prevalence of congenital heart defects (CHDs) have been reported; however, studies of the contemporary UK population are lacking. We investigated ethnic variations in incidence of serious CHDs requiring cardiac intervention before 1 year of age. All infants who had a cardiac intervention in England and Wales between 1 January 2005 and 31 December 2010 were identified in the national congenital heart disease surgical audit and matched with paediatric intensive care admission records to create linked individual child records. Agreement in reporting of ethnic group by each audit was evaluated. For infants born 1 January 2006 to 31 December 2009, we calculated incidence rate ratios (IRRs) for CHDs by ethnicity and investigated age at intervention, antenatal diagnosis and area deprivation. We identified 5350 infants (2940 (55.0%) boys). Overall CHD incidence was significantly higher in Asian and Black ethnic groups compared with the White reference population (incidence rate ratios (IRR) (95% CIs): Asian 1.5 (1.4 to 1.7); Black 1.4 (1.3 to 1.6)); incidence of specific CHDs varied by ethnicity. No significant differences in age at intervention or antenatal diagnosis rates were identified but affected children from non-White ethnic groups were more likely to be living in deprived areas than White children. Significant ethnic variations exist in the incidence of CHDs, including for specific defects with high infant mortality. It is essential that healthcare provision mitigates ethnic disparity, including through timely identification of CHDs at screening, supporting parental choice and effective interventions. Future research should explore the factors underlying ethnic variation and impact on longer-term outcomes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Hospital Variation in Perioperative Complications for Laparoscopic Sleeve Gastrectomy in Michigan

PubMed Central

Pradarelli, Jason C.; Varban, Oliver A.; Ghaferi, Amir A.; Weiner, Matthew; Carlin, Arthur M.; Dimick, Justin B.

2015-01-01

Structured Abstract Background Laparoscopic sleeve gastrectomy has recently surpassed gastric bypass and laparoscopic adjustable gastric banding as the most common weight-loss procedure. Previously, substantial concerns existed regarding variation in perioperative safety with bariatric surgery. This study aimed to assess rates of perioperative complications for laparoscopic sleeve gastrectomy across hospitals and in relation to procedure volume. Study Design We analyzed 8,693 patients who underwent laparoscopic sleeve gastrectomy from 2013 through 2014 across 40 hospitals in the Michigan Bariatric Surgery Collaborative. Mixed-effects logistic regression was used to assess hospital variation in risk- and reliability-adjusted rates of overall and serious 30-day complications and their relationship with hospital annual stapling procedure volume (gastric bypass and sleeve gastrectomy). Results Overall, 5.4% of patients experienced perioperative complications. Adjusted rates of overall complications varied three-fold across hospitals, ranging from 3.6% (95% CI, 1.9–6.8%) to 11.0% (95% CI, 7.7–15.5%). Serious complications occurred in just 1.2% of patients and varied minimally. In this analysis, hospital volume was not associated with overall or serious complications. The 1 hospital with significantly lower overall complication rates was high-volume (≥125 procedures/year); however, of the 4 hospitals with significantly higher complication rates, 3 were medium-volume (50–124 procedures/year) and 1 was high-volume. The remaining hospitals were not significantly different than the cohort mean. Conclusions Serious complications among patients undergoing laparoscopic sleeve gastrectomy were relatively infrequent. Rates of overall complications varied widely across Michigan hospitals enrolled in a quality collaborative, although this variation was unrelated to volume standards required for accreditation as a comprehensive bariatric surgery center. PMID:26506567

Variation in the Diagnosis and Management of Appendicitis at Canadian Pediatric Hospitals.

PubMed

Thompson, Graham C; Schuh, Suzanne; Gravel, Jocelyn; Reid, Sarah; Fitzpatrick, Eleanor; Turner, Troy; Bhatt, Maala; Beer, Darcy; Blair, Geoffrey; Eccles, Robin; Jones, Sarah; Kilgar, Jennifer; Liston, Natalia; Martin, John; Hagel, Brent; Nettel-Aguirre, Alberto

2015-07-01

The objective was to characterize the variations in practice in the diagnosis and management of children admitted to hospitals from Canadian pediatric emergency departments (EDs) with suspected appendicitis, specifically the timing of surgical intervention, ED investigations, and management strategies. Twelve sites participated in this retrospective health record review. Children aged 3 to 17 years admitted to the hospital with suspected appendicitis were eligible. Site-specific demographics, investigations, and interventions performed were recorded and compared. Factors associated with after-hours surgery were determined using generalized estimating equations logistic regression. Of the 619 children meeting eligibility criteria, surgical intervention was performed in 547 (88%). After-hours surgery occurred in 76 of the 547 children, with significant variation across sites (13.9%, 95% confidence interval = 7.1% to 21.6%, p < 0.001). The overall perforation rate was 17.4% (95 of 547), and the negative appendectomy rate was 6.8% (37 of 547), varying across sites (p = 0.004 and p = 0.036, respectively). Use of inflammatory markers (p < 0.001), blood cultures (p < 0.001), ultrasound (p = 0.001), and computed tomography (p = 0.001) also varied by site. ED administration of narcotic analgesia and antibiotics varied across sites (p < 0.001 and p = 0.001, respectively), as did the type of surgical approach (p < 0.001). After-hours triage had a significant inverse association with after-hours surgery (p = 0.014). Across Canadian pediatric EDs, there exists significant variation in the diagnosis and management of children with suspected appendicitis. These results indicate that the best diagnostic and management strategies remain unclear and support the need for future prospective, multicenter studies to identify strategies associated with optimal patient outcomes. © 2015 by the Society for Academic Emergency Medicine.

Ethnic and socioeconomic variation in incidence of congenital heart defects

PubMed Central

Knowles, Rachel L; Ridout, Deborah; Crowe, Sonya; Bull, Catherine; Wray, Jo; Tregay, Jenifer; Franklin, Rodney C; Barron, David J; Cunningham, David; Parslow, Roger C; Brown, Katherine L

2017-01-01

Introduction Ethnic differences in the birth prevalence of congenital heart defects (CHDs) have been reported; however, studies of the contemporary UK population are lacking. We investigated ethnic variations in incidence of serious CHDs requiring cardiac intervention before 1 year of age. Methods All infants who had a cardiac intervention in England and Wales between 1 January 2005 and 31 December 2010 were identified in the national congenital heart disease surgical audit and matched with paediatric intensive care admission records to create linked individual child records. Agreement in reporting of ethnic group by each audit was evaluated. For infants born 1 January 2006 to 31 December 2009, we calculated incidence rate ratios (IRRs) for CHDs by ethnicity and investigated age at intervention, antenatal diagnosis and area deprivation. Results We identified 5350 infants (2940 (55.0%) boys). Overall CHD incidence was significantly higher in Asian and Black ethnic groups compared with the White reference population (incidence rate ratios (IRR) (95% CIs): Asian 1.5 (1.4 to 1.7); Black 1.4 (1.3 to 1.6)); incidence of specific CHDs varied by ethnicity. No significant differences in age at intervention or antenatal diagnosis rates were identified but affected children from non-White ethnic groups were more likely to be living in deprived areas than White children. Conclusions Significant ethnic variations exist in the incidence of CHDs, including for specific defects with high infant mortality. It is essential that healthcare provision mitigates ethnic disparity, including through timely identification of CHDs at screening, supporting parental choice and effective interventions. Future research should explore the factors underlying ethnic variation and impact on longer-term outcomes. PMID:27986699

Biomass Allocation Patterns Are Linked to Genotypic Differences in Whole-Plant Transpiration Efficiency in Sunflower

PubMed Central

Velázquez, Luciano; Alberdi, Ignacio; Paz, Cosme; Aguirrezábal, Luis

2017-01-01

Increased transpiration efficiency (the ratio of biomass to water transpired, TE) could lead to increased drought tolerance under some water deficit scenarios. Intrinsic (i.e., leaf-level) TE is usually considered as the primary source of variation in whole-plant TE, but empirical data usually contradict this assumption. Sunflower has a significant variability in TE, but a better knowledge of the effect of leaf and plant-level traits could be helpful to obtain more efficient genotypes for water use. The objective of this study was, therefore, to assess if genotypic variation in whole-plant TE is better related to leaf- or plant-level traits. Three experiments were conducted, aimed at verifying the existence of variability in whole-plant TE and whole-plant and leaf-level traits, and to assess their correlation. Sunflower public inbred lines and a segregating population of recombinant inbred lines were grown under controlled conditions and subjected to well-watered and water-deficit treatments. Significant genotypic variation was found for TE and related traits. These differences in whole-plant transpiration efficiency, both between genotypes and between plants within each genotype, showed no association to leaf-level traits, but were significantly and negatively correlated to biomass allocation to leaves and to the ratio of leaf area to total biomass. These associations are likely of a physiological origin, and not only a consequence of genetic linkage in the studied population. These results suggest that genotypic variation for biomass allocation could be potentially exploited as a source for increased transpiration efficiency in sunflower breeding programmes. It is also suggested that phenotyping for TE in this species should not be restricted to leaf-level measurements, but also include measurements of plant-level traits, especially those related to biomass allocation between photosynthetic and non-photosynthetic organs. PMID:29204153

Biomass Allocation Patterns Are Linked to Genotypic Differences in Whole-Plant Transpiration Efficiency in Sunflower.

PubMed

Velázquez, Luciano; Alberdi, Ignacio; Paz, Cosme; Aguirrezábal, Luis; Pereyra Irujo, Gustavo

2017-01-01

Increased transpiration efficiency (the ratio of biomass to water transpired, TE) could lead to increased drought tolerance under some water deficit scenarios. Intrinsic (i.e., leaf-level) TE is usually considered as the primary source of variation in whole-plant TE, but empirical data usually contradict this assumption. Sunflower has a significant variability in TE, but a better knowledge of the effect of leaf and plant-level traits could be helpful to obtain more efficient genotypes for water use. The objective of this study was, therefore, to assess if genotypic variation in whole-plant TE is better related to leaf- or plant-level traits. Three experiments were conducted, aimed at verifying the existence of variability in whole-plant TE and whole-plant and leaf-level traits, and to assess their correlation. Sunflower public inbred lines and a segregating population of recombinant inbred lines were grown under controlled conditions and subjected to well-watered and water-deficit treatments. Significant genotypic variation was found for TE and related traits. These differences in whole-plant transpiration efficiency, both between genotypes and between plants within each genotype, showed no association to leaf-level traits, but were significantly and negatively correlated to biomass allocation to leaves and to the ratio of leaf area to total biomass. These associations are likely of a physiological origin, and not only a consequence of genetic linkage in the studied population. These results suggest that genotypic variation for biomass allocation could be potentially exploited as a source for increased transpiration efficiency in sunflower breeding programmes. It is also suggested that phenotyping for TE in this species should not be restricted to leaf-level measurements, but also include measurements of plant-level traits, especially those related to biomass allocation between photosynthetic and non-photosynthetic organs.

Preventing infections in nursing homes: A survey of infection control practices in southeast Michigan

PubMed Central

Mody, Lona; Langa, Kenneth M.; Saint, Sanjay; Bradley, Suzanne F.

2012-01-01

Background Studies on adherence to infection control policies in nursing homes (NHs) are limited. This pilot study explores the use of various infection control practices and the role of infection control practitioners in southeast Michigan NHs. Methods A 43-item self-administered questionnaire and explanatory cover letter were mailed to 105 licensed NHs in southeast Michigan. A second mailing was sent to the nonresponders 4 weeks later. Results Significant variability existed in adoption of various infection control measures with respect to time spent in infection control activities (50% of facilities having a full-time infection control practitioner), definitions used in monitoring infections, and immunization rates (influenza: range, 0%–100%; mean, 73.2%; pneumococcal: range, 0%–100%; mean, 38.5%). Conclusion Although strides have been made in infection control research in NHs, significant variations exist in implementation of infection control methods and guidelines. Future research should focus on identifying barriers to infection control in NHs. PMID:16216667

Patterns of change in high frequency precipitation variability over North America.

PubMed

Roque-Malo, Susana; Kumar, Praveen

2017-09-18

Precipitation variability encompasses attributes associated with the sequencing and duration of events of the full range of magnitudes. However, climate change studies have largely focused on extreme events. Using analyses of long-term weather station data, we show that high frequency events, such as fraction of wet days in a year and average duration of wet and dry periods, are undergoing significant changes across North America. Further, these changes are more prevalent and larger than those associated with extremes. Such trends also exist for events of a range of magnitudes. Existence of localized clusters with opposing trend to that of broader geographic variation illustrates the role of microclimate and other drivers of trends. Such hitherto unknown patterns over the entire North American continent have the potential to significantly inform our characterization of the resilience and vulnerability of a broad range of ecosystems and agricultural and socio-economic systems. They can also set new benchmarks for climate model assessments.

Solutions to variational inequalities of parabolic type

NASA Astrophysics Data System (ADS)

Zhu, Yuanguo

2006-09-01

The existence of strong solutions to a kind of variational inequality of parabolic type is investigated by the theory of semigroups of linear operators. As an application, an abstract semi permeable media problem is studied.

Characterization of Relatively Large Track Geometry Variations

DOT National Transportation Integrated Search

1982-03-01

An analysis of existing track geometry data is described from which the signatures of key track geometry variations related to severe track-train dynamic interaction are identified and quantified. Mathematical representations of these signatures are ...

Study on the Geomagnetic Short Period Variations of the Northwestern Yunnan

NASA Astrophysics Data System (ADS)

Yuan, Y.; Li, Q.; Cai, J.

2015-12-01

The Northwestern Yunnan is located in the interaction area between the Eurasian plate and the India plate. This area has been the ideal place for the research of continental dynamics and the prediction for risk region of strong earthquake for its complex tectonic environment and frequent seismic activity. Therefore the study on the geomagnetic short period variations is of great significance in the exploration of deep electrical structure, analysis of the seismic origin and deep geodynamics in the Northwestern Yunnan of China . This paper is based on the geomagnetic data from the magnetometer array with 8 sites built in the northwestern Yunnan to explore the deep electrical structure by the method of geomagnetic depth sounding. Firstly, we selected a total of 183 geomagnetic short period events at the range of 6min to 120min period. And we found a north northwest dividing line, of which two sides has the opposite value in the vertical component variation amplitude, which indicates the obvious conductivity anomaly underground. Secondly, the contour maps of the ratio of vertical component and horizontal component variation amplitude ΔZ/ΔH in different periods reflects the changes of a high conductivity belt's direction and position. In addition, the induction arrows maps within the period of 2 - 256min also shows that on the two sides of the dividing line the induction vectors deviate from each other, and the amplitude and direction of vectors varies with periods regularly. In the light of this, we infer that a high conductivity belt probably exists, which stretches from the deep crust to uppermost mantle and changes with depth constantly with the reference of magnetotelluric sounding. In the end of this paper, the staggered grid finite difference method is used to model the simplified three-dimensional high conductivity anomaly, and the result shows magnetic field distributions are consistent with the observed geomagnetic short period variations characteristics in different periods, which confirms the existence of the high conductivity belt. According to the characteristics of the short period geomagnetic variation above, in combination with the results of previous studies, the synthetic action of partial melting and fluid might be the origin of the belt.

Variation in Treatment of Displaced Geriatric Acetabular Fractures Among 15 Level-I Trauma Centers.

PubMed

Manson, Theodore T; Reider, Lisa; OʼToole, Robert V; Scharfstein, Daniel O; Tornetta, Paul; Gary, Joshua L

2016-09-01

To document the initial treatment of displaced acetabular fractures among older adults across multiple trauma centers and to investigate the factors that influence the decision to operate and the choice of operative procedure [open reduction internal fixation (ORIF) vs. total hip arthroplasty (THA)]. Retrospective observational study. Fifteen US level-I trauma centers participating in the Major Extremity Trauma Research Consortium. Overall, 269 patients aged 60 years or older admitted for the treatment of a displaced acetabular fracture. None. Treatment. Sixty percent of fractures (n = 162) were treated operatively. Younger age (<80 years), injury from high-energy mechanism, fractures with femoral head impaction, and fractures without hip congruency were significantly associated with receiving operative treatment (P < 0.05). Significant site variation in operative versus nonoperative treatment occurred even after accounting for these factors (P = 0.0044). Among operatively treated patients, 88% (n = 142) received ORIF and 12% (n = 20) received THA as the initial treatment. Women were more likely to be treated with initial THA compared with men; of the known risk factors for poor outcomes with ORIF (ie, dome or roof impaction, femoral head impaction, or posterior wall involvement), only dome impaction was significantly associated with receiving initial THA (P < 0.05). Currently, no treatment guidelines exist for acetabular fractures in older adults, which likely explains the significant site variation in operative versus nonoperative treatment. This study identifies patient and injury factors that drive treatment decisions, which will be important in planning and designing future trials needed to determine the best treatment for these fractures.

The behavioral ecology of cultural psychological variation.

PubMed

Sng, Oliver; Neuberg, Steven L; Varnum, Michael E W; Kenrick, Douglas T

2018-04-23

Recent work has documented a wide range of important psychological differences across societies. Multiple explanations have been offered for why such differences exist, including historical philosophies, subsistence methods, social mobility, social class, climactic stresses, and religion. With the growing body of theory and data, there is an emerging need for an organizing framework. We propose here that a behavioral ecological perspective, particularly the idea of adaptive phenotypic plasticity, can provide an overarching framework for thinking about psychological variation across cultures and societies. We focus on how societies vary as a function of six important ecological dimensions: density, relatedness, sex ratio, mortality likelihood, resources, and disease. This framework can: (a) highlight new areas of research, (b) integrate and ground existing cultural psychological explanations, (c) integrate research on variation across human societies with research on parallel variations in other animal species, (d) provide a way for thinking about multiple levels of culture and cultural change, and (e) facilitate the creation of an ecological taxonomy of societies, from which one can derive specific predictions about cultural differences and similarities. Finally, we discuss the relationships between the current framework and existing perspectives. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Variations in the anatomy of the celiac trunk: A systematic review and clinical implications.

PubMed

Panagouli, Eleni; Venieratos, Dionysios; Lolis, Evangelos; Skandalakis, Panagiotis

2013-12-01

The normal pattern of the celiac trunk (CT) implies its bifurcation to three branches, the common hepatic, the splenic and the left gastric artery. According to the available literature the CT presents several anatomical variations. The purpose of our study is to investigate the different types of these variations, the corresponding incidences and the probable influence of genetic factors, as they are presented in the existing literature. Four databases were searched for eligible articles for the period up to January 2013 and a total of 36 studies were collected. The CT was trifurcated into the three basic branches in the 89.42% (10,906/12,196) of the cases. Bifurcation of the CT occurred in the 7.40% of the pooled samples (903/12,196). Absence of the CT was the rarest variation with a percentage of 0.38% (46/12,196), hepatosplenomesenteric trunk was found in 49 out of the 12,196 cases (0.40%) and the celiacomesenteric trunk presented an incidence of 0.76% (93/12,196). Other variations of the CT were detected in the 1.64% of the pooled cases (199/12,196). The 14.9% of the cases in the cadaveric series (489/3278 specimens), the 10.5% in the imaging series (675/6501 specimens) and the 4.6% (104/2261) in the liver transplantation series presented variations. These differences are statistically significant (p<0.001). The Japanese and Korean populations presented more variations in the CT than Caucasians (p<0.05 and p<0.001). Negro, colored and black populations presented more variations of the CT than Indian ones (p>0.05). Using those data, a novel classification of CT variations is proposed. Copyright © 2013 Elsevier GmbH. All rights reserved.

Genomic variation among populations of threatened coral: Acropora cervicornis.

PubMed

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, informing conservation goals with evolutionary implications.

The impact of transposable elements on mammalian development

PubMed Central

Garcia-Perez, Jose L.; Widmann, Thomas J.; Adams, Ian R.

2018-01-01

Summary Despite often being classified as selfish or junk DNA, transposable elements (TEs) are a group of abundant genetic sequences that significantly impact on mammalian development and genome regulation. In recent years, our understanding of how pre-existing TEs affect genome architecture, gene regulatory networks and protein function during mammalian embryogenesis has dramatically expanded. In addition, the mobilization of active TEs in selected cell types has been shown to generate genetic variation during development and in fully differentiated tissues. Importantly, the ongoing domestication and evolution of TEs appears to provide a rich source of regulatory elements, functional modules and genetic variation that fuels the evolution of mammalian developmental processes. Here, we review the functional impact that TEs exert on mammalian developmental processes and how the somatic activity of TEs can influence gene regulatory networks. PMID:27875251

Genetic diversity of functional food species Spinacia oleracea L. by protein markers.

PubMed

Rashid, M; Yousaf, Z; Haider, M S; Khalid, S; Rehman, H A; Younas, A; Arif, A

2014-01-01

Exploration of genetic diversity contributes primarily towards crop improvement. Spinaciaoleracea L. is a functional food species but unfortunately the genetic diversity of this vegetable is still unexplored. Therefore, this research was planned to explore the genetic diversity of S. oleracea by using morphological and protein markers. Protein profile of 25 accessions was generated on sodium dodecyl sulphate polyacrylamide gel. Total allelic variation of 27 bands was found. Out of these, 20 were polymorphic and the rest of the bands were monomorphic. Molecular weights of the bands ranged from 12.6 to 91.2 kDa. Major genetic differences were observed in accession 20541 (Peshawar) followed by 20180 (Lahore) and 19902 (AVRDC). Significant differences exist in the protein banding pattern. This variation can further be studied by advanced molecular techniques, including two-dimensional electrophoresis and DNA markers.

Explaining variance of avian malaria infection in the wild: the importance of host density, habitat, individual life-history and oxidative stress.

PubMed

Isaksson, Caroline; Sepil, Irem; Baramidze, Vladimer; Sheldon, Ben C

2013-04-08

Avian malaria (Plasmodium sp.) is globally widespread, but considerable variation exists in infection (presence/absence) patterns at small spatial scales. This variation can be driven by variation in ecology, demography, and phenotypic characters, in particular those that influence the host's resistance. Generation of reactive oxygen species (ROS) is one of the host's initial immune responses to combat parasitic invasion. However, long-term ROS exposure can harm the host and the redox response therefore needs to be adjusted according to infection stage and host phenotype. Here we use experimental and correlational approaches to assess the relative importance of host density, habitat composition, individual level variation and redox physiology for Plasmodium infection in a wild population of great tits, Parus major. We found that 36% of the great tit population was infected with Plasmodium (22% P. relictum and 15% P. circumflexum prevalence) and that patterns of infection were Plasmodium species-specific. First, the infection of P. circumflexum was significantly higher in areas with experimental increased host density, whereas variation in P. relictum infection was mainly attributed to age, sex and reproduction. Second, great tit antioxidant responses - total and oxidizied glutathione - showed age- , sex- and Plasmodium species-specific patterns between infected and uninfected individuals, but reactive oxygen metabolites (ROM) showed only a weak explanatory power for patterns of P. relictum infection. Instead ROM significantly increased with Plasmodium parasitaemia. These results identify some key factors that influence Plasmodium infection in wild birds, and provide a potential explanation for the underlying physiological basis of recently documented negative effects of chronic avian malaria on survival and reproductive success.

Hospital organizational factors affect the use of immediate breast reconstruction after mastectomy for breast cancer in the Netherlands.

PubMed

Schreuder, K; van Bommel, A C M; de Ligt, K M; Maduro, J H; Vrancken Peeters, M T F D; Mureau, M A M; Siesling, S

2017-08-01

Significant hospital variation in the use of immediate breast reconstruction (IBR) after mastectomy exists in the Netherlands. Aims of this study were to identify hospital organizational factors affecting the use of IBR after mastectomy for ductal carcinoma in situ (DCIS) or invasive breast cancer (BC) and to analyze whether these factors explain the variation. Patients with DCIS or primary invasive BC treated with mastectomy between 2011 and 2013 were selected from the national NABON Breast Cancer Audit. Hospital and organizational factors were collected with an online web-based survey. Regression analyses were performed to determine whether these factors accounted for the hospital variation. In total, 78% (n = 72) of all Dutch hospitals participated in the survey. In these hospitals 16,471 female patients underwent a mastectomy for DCIS (n = 1,980) or invasive BC (n = 14,491) between 2011 and 2014. IBR was performed in 41% of patients with DCIS (hospital range 0-80%) and in 17% of patients with invasive BC (hospital range 0-62%). Hospital type, number of plastic surgeons available and attendance of a plastic surgeon at the MDT meeting increased IBR rates. For invasive BC, higher percentage of mastectomies and more weekly MDT meetings also significantly increased IBR rates. Adjusted data demonstrated decreased IBR rates for DCIS (average 35%, hospital range 0-49%) and invasive BC (average 15%, hospital range 0-18%). Hospital organizational factors affect the use of IBR in the Netherlands. Although only partly explaining hospital variation, optimization of these factors could lead to less variation in IBR rates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inter-Ethnic/Racial Facial Variations: A Systematic Review and Bayesian Meta-Analysis of Photogrammetric Studies

PubMed Central

Wen, Yi Feng; Wong, Hai Ming; Lin, Ruitao; Yin, Guosheng; McGrath, Colman

2015-01-01

Background Numerous facial photogrammetric studies have been published around the world. We aimed to critically review these studies so as to establish population norms for various angular and linear facial measurements; and to determine inter-ethnic/racial facial variations. Methods and Findings A comprehensive and systematic search of PubMed, ISI Web of Science, Embase, and Scopus was conducted to identify facial photogrammetric studies published before December, 2014. Subjects of eligible studies were either Africans, Asians or Caucasians. A Bayesian hierarchical random effects model was developed to estimate posterior means and 95% credible intervals (CrI) for each measurement by ethnicity/race. Linear contrasts were constructed to explore inter-ethnic/racial facial variations. We identified 38 eligible studies reporting 11 angular and 18 linear facial measurements. Risk of bias of the studies ranged from 0.06 to 0.66. At the significance level of 0.05, African males were found to have smaller nasofrontal angle (posterior mean difference: 8.1°, 95% CrI: 2.2°–13.5°) compared to Caucasian males and larger nasofacial angle (7.4°, 0.1°–13.2°) compared to Asian males. Nasolabial angle was more obtuse in Caucasian females than in African (17.4°, 0.2°–35.3°) and Asian (9.1°, 0.4°–17.3°) females. Additional inter-ethnic/racial variations were revealed when the level of statistical significance was set at 0.10. Conclusions A comprehensive database for angular and linear facial measurements was established from existing studies using the statistical model and inter-ethnic/racial variations of facial features were observed. The results have implications for clinical practice and highlight the need and value for high quality photogrammetric studies. PMID:26247212

Inter-Ethnic/Racial Facial Variations: A Systematic Review and Bayesian Meta-Analysis of Photogrammetric Studies.

PubMed

Wen, Yi Feng; Wong, Hai Ming; Lin, Ruitao; Yin, Guosheng; McGrath, Colman

2015-01-01

Numerous facial photogrammetric studies have been published around the world. We aimed to critically review these studies so as to establish population norms for various angular and linear facial measurements; and to determine inter-ethnic/racial facial variations. A comprehensive and systematic search of PubMed, ISI Web of Science, Embase, and Scopus was conducted to identify facial photogrammetric studies published before December, 2014. Subjects of eligible studies were either Africans, Asians or Caucasians. A Bayesian hierarchical random effects model was developed to estimate posterior means and 95% credible intervals (CrI) for each measurement by ethnicity/race. Linear contrasts were constructed to explore inter-ethnic/racial facial variations. We identified 38 eligible studies reporting 11 angular and 18 linear facial measurements. Risk of bias of the studies ranged from 0.06 to 0.66. At the significance level of 0.05, African males were found to have smaller nasofrontal angle (posterior mean difference: 8.1°, 95% CrI: 2.2°-13.5°) compared to Caucasian males and larger nasofacial angle (7.4°, 0.1°-13.2°) compared to Asian males. Nasolabial angle was more obtuse in Caucasian females than in African (17.4°, 0.2°-35.3°) and Asian (9.1°, 0.4°-17.3°) females. Additional inter-ethnic/racial variations were revealed when the level of statistical significance was set at 0.10. A comprehensive database for angular and linear facial measurements was established from existing studies using the statistical model and inter-ethnic/racial variations of facial features were observed. The results have implications for clinical practice and highlight the need and value for high quality photogrammetric studies.

Neonatal Intensive Care Unit Safety Culture Varies Widely

PubMed Central

Profit, Jochen; Etchegaray, Jason; Petersen, Laura A; Sexton, J Bryan; Hysong, Sylvia J; Mei, Minghua; Thomas, Eric J

2013-01-01

background Variation in health care delivery and outcomes in NICUs may be partly explained by differences in safety culture. objective To describe NICU caregiver assessments of safety culture, explore the variability within and between NICUs on safety culture domains, and test for association with caregiver characteristics. methods We surveyed NICU caregivers in a convenience sample of 12 hospitals from a single health care system, using the Safety Attitudes Questionnaire (SAQ). The six scales of the SAQ include teamwork climate, safety climate, job satisfaction, stress recognition, perception of management, and working conditions. For each NICU we calculated scale means, standard deviations and percent positives (percent agreement). results We found substantial variation in safety culture domains among participating NICUs. A composite mean score across the six safety culture domains ranged from 56.3 to 77.8 on a 100-point scale and NICUs in the top four NICUs were significantly different from the bottom four (p < .001). Across the six domains, respondent assessments varied widely, but were least positive on perceptions of management (3–80% positive; mean 33.3%) and stress recognition (18–61% positive; mean 41.3%). Comparisons of SAQ scale scores between NICUs and a previously published cohort of adult ICUs generally revealed higher scores for NICUs. Physicians composite scores were 8.2 (p = .04) and 9.5 (p =.02) points higher than nurses and ancillary personnel. conclusion Significant variation and scope for improvement in safety culture exists among this sample of NICUs. The NICU variation was similar to variation in adult ICUs, but NICU scores were generally higher than adult ICU scores. Future studies should validate whether safety culture as measured with the SAQ correlates with clinical and operational outcomes in the NICU setting. PMID:21930691

Temporal variability of foliar nutrients: responses to nitrogen deposition and prescribed fire in a temperate steppe

USGS Publications Warehouse

Lü, Xiao-Tao; Reed, Sasha C.; Hou, Shuang-Li; Hu, Yan-Yu; Wei, Hai-Wei; Lü, Fu-Mei; Cui, Qiang; Han, Xing Guo

2017-01-01

Plant nutrient concentrations and stoichiometry drive fundamental ecosystem processes, with important implications for primary production, diversity, and ecosystem sustainability. While a range of evidence exists regarding how plant nutrients vary across spatial scales, our understanding of their temporal variation remains less well understood. Nevertheless, we know nutrients regulate plant function across time, and that important temporal controls could strongly interact with environmental change. Here, we report results from a 3-year assessment of inter-annual changes of foliar nitrogen (N) and phosphorus (P) concentrations and stoichiometry in three dominant grasses in response to N deposition and prescribed fire in a temperate steppe of northern China. Foliar N and P concentrations and their ratios varied greatly among years, with this temporal variation strongly related to inter-annual variation in precipitation. Nitrogen deposition significantly increased foliar N concentrations and N:P ratios in all species, while fire significantly altered foliar N and P concentrations but had no significant impacts on N:P ratios. Generally, N addition enhanced the temporal stability of foliar N and decreased that of foliar P and of N:P ratios. Our results indicate that plant nutrient status and response to environmental change are temporally dynamic and that there are differential effects on the interactions between environmental change drivers and timing for different nutrients. These responses have important implications for consideration of global change effects on plant community structure and function, management strategies, and the modeling of biogeochemical cycles under global change scenarios.

Practice Variations in the Management of Inflammatory Bowel Disease Between Pediatric and Adult Gastroenterologists.

PubMed

Assa, Amit; Avni, Irit; Ben-Bassat, Ofer; Niv, Yaron; Shamir, Raanan

2016-03-01

Different practice guidelines and consensus statements for both pediatric- and adult-onset inflammatory bowel disease exist. Although variations in medical care among gastroenterologists are common, it is unknown whether there are fundamental differences between disciplines. The primary aim of the present study was to investigate differences in common practices across disciplines. This was a prospective, questionnaire-based survey of gastroenterologists attending gastroenterology meetings in Israel. The questionnaire covered attitudes to medical resources, diagnostic and follow-up measures as well as therapeutic approaches. Overall, 120 (60%) of the approached adult gastroenterologists (AGs) and 49 (75%) pediatric gastroenterologists (PGs) completed the questionnaire. The 2 groups differed significantly in various practice areas. Pediatric patients are seen more frequently and for longer appointments. PGs tend to assess thiopurine metabolites (96% vs 47%) more often during treatment. There is a significant variation in practice between groups concerning infectious serology status and vaccinations. Methotrexate in Crohn patients is used more commonly by PGs (55% vs 22%). Long-term combination therapy of thiopurines and anti-tumor necrosis factorα agents is used more often by AGs. In patients with ulcerative colitis AGs use oral 5-aminosalicylic acid once daily (51% vs 21%) and add rectal agents from the first day of treatment (72% vs 35%) more often as compared with PGs. This study demonstrates that common practices in inflammatory bowel disease patients differ significantly between adult and pediatric practitioners. These findings call for investigating the reasons for these differences and promoting strategies to diminish these gaps.

Rethinking the starch digestion hypothesis for AMY1 copy number variation in humans.

PubMed

Fernández, Catalina I; Wiley, Andrea S

2017-08-01

Alpha-amylase exists across taxonomic kingdoms with a deep evolutionary history of gene duplications that resulted in several α-amylase paralogs. Copy number variation (CNV) in the salivary α-amylase gene (AMY1) exists in many taxa, but among primates, humans appear to have higher average AMY1 copies than nonhuman primates. Additionally, AMY1 CNV in humans has been associated with starch content of diets, and one known function of α-amylase is its involvement in starch digestion. Thus high AMY1 CNV is considered to result from selection favoring more efficient starch digestion in the Homo lineage. Here, we present several lines of evidence that challenge the hypothesis that increased AMY1 CNV is an adaptation to starch consumption. We observe that α- amylase plays a very limited role in starch digestion, with additional steps required for starch digestion and glucose metabolism. Specifically, we note that α-amylase hydrolysis only produces a minute amount of free glucose with further enzymatic digestion and glucose absorption being rate-limiting steps for glucose availability. Indeed α-amylase is nonessential for starch digestion since sucrase-isomaltase and maltase-glucoamylase can hydrolyze whole starch granules while releasing glucose. While higher AMY1 CN and CNV among human populations may result from natural selection, existing evidence does not support starch digestion as the major selective force. We report that in humans α-amylase is expressed in several other tissues where it may have potential roles of evolutionary significance. © 2017 Wiley Periodicals, Inc.

Strongly nonlinear parabolic variational inequalities.

PubMed

Browder, F E; Brézis, H

1980-02-01

An existence and uniqueness result is established for a general class of variational inequalities for parabolic partial differential equations of the form partial differentialu/ partial differentialt + A(u) + g(u) = f with g nondecreasing but satisfying no growth condition. The proof is based upon a type of compactness result for solutions of variational inequalities that should find a variety of other applications.

Test Format and the Variation of Gender Achievement Gaps within the United States

ERIC Educational Resources Information Center

Reardon, Sean; Fahle, Erin; Kalogrides, Demetra; Podolsky, Anne; Zarate, Rosalia

2016-01-01

Prior research demonstrates the existence of gender achievement gaps and the variation in the magnitude of these gaps across states. This paper characterizes the extent to which the variation of gender achievement gaps on standardized tests across the United States can be explained by differing state accountability test formats. A comprehensive…

Algal-bacterial co-variation in streams: a cross-stream comparison

Treesearch

Xueqing Gao; Ola A. Olapade; Mark W. Kershner; Laura G. Leff

2004-01-01

Algal-bacterial co-variation has been frequently observed in lentic and marine environments, but the existence of such relationships in lotic ecosystems is not well established. To examine possible co-variation, bacterial number and chlorophyll-a concentration in water and sediments of nine streams from different regions in the USA were examined. In the water, a strong...

Variations in algorithm implementation among quantitative texture analysis software packages

NASA Astrophysics Data System (ADS)

Foy, Joseph J.; Mitta, Prerana; Nowosatka, Lauren R.; Mendel, Kayla R.; Li, Hui; Giger, Maryellen L.; Al-Hallaq, Hania; Armato, Samuel G.

2018-02-01

Open-source texture analysis software allows for the advancement of radiomics research. Variations in texture features, however, result from discrepancies in algorithm implementation. Anatomically matched regions of interest (ROIs) that captured normal breast parenchyma were placed in the magnetic resonance images (MRI) of 20 patients at two time points. Six first-order features and six gray-level co-occurrence matrix (GLCM) features were calculated for each ROI using four texture analysis packages. Features were extracted using package-specific default GLCM parameters and using GLCM parameters modified to yield the greatest consistency among packages. Relative change in the value of each feature between time points was calculated for each ROI. Distributions of relative feature value differences were compared across packages. Absolute agreement among feature values was quantified by the intra-class correlation coefficient. Among first-order features, significant differences were found for max, range, and mean, and only kurtosis showed poor agreement. All six second-order features showed significant differences using package-specific default GLCM parameters, and five second-order features showed poor agreement; with modified GLCM parameters, no significant differences among second-order features were found, and all second-order features showed poor agreement. While relative texture change discrepancies existed across packages, these differences were not significant when consistent parameters were used.

Studies on the Origins and Nature of Critical Current Variations in Rare Earth Barium Copper Oxide Coated Conductors

NASA Astrophysics Data System (ADS)

Hu, Xinbo

REBCO (REBa2Cu3O7-delta, RE=rare earth elements) coated conductor (CC) is one of the best candidates for building high-field magnets and it has been improved greatly in recent years. CC overcome the grain boundary problem by using either a rolling assisted biaxially textured substrate (RABiTS) or ion beam assisted deposition (IBAD) of a template for the REBCO. Artificial pinning centers were also introduced to increase critical current density. Despite all these improvements, one significant residual problem is lengthwise critical current (Ic) variations of the CCs. Characterizations of CCs can not only identify the variations, but also provide insight that can help improve the manufacturing process. This study focuses on cross-sectional and vortex pinning variations in CCs. With the reel-to-reel Ic and magnetization measurement system (YateStar), a systematic study has been carried out for CCs made in the last 5-6 years as this technology has rapidly developed. We found that cross-section variations exist for almost all conductors because of width variations. But this contribution to the total Ic variation is small. Vortex pinning variations are found to be the main reason for Ic variations, especially for conductors from different production runs. Even for conductors from the same run, pinning variations are often present. Microscopy studies show that the density and length of BaZrO3 (BZO) nanorods vary between different conductors even though they have nominally the same specifications. Pinning variations in one single tape are mostly attributed to the size variations of BZO nanorods and the configurations of RE2O3 precipitates. Deconstruction of magnet coils and cables were carried out to understand the reasons for in-service degradation. The prototype coil for the 32 T project was safely quenched more than 100 times but it degraded in 3 spontaneous quenches (conducted in an accelerated fatigue testing campaign at ramp rates much larger than service specification). Its pancake coil deconstruction showed three extremely localized burned regions, whose temperature went to over 800°C based on the appearance of a Cu-Ag eutectic above the damaged REBCO layer. Transverse propagation of the damage was almost as effective as longitudinal propagation. Transmission electron microscope images show that thicker BaZrO 3 (BZO) nanorods exist near the centers of damaged zones, compared to longer and thinner BZO nanorods from normal, good regions. Because of the lack of detailed Ic(x) characterizations of the length prior to use, the cause the cause of the coil degradation is not clear. It is possible that local degradation of the vortex pinning initiated the final quenches but another possibility is indicated by deconstruction of a no-insulation coil, which reached 45.5 T in a background field of 31 T. In this case no burn marks were observed but some tapes were heavily deformed on one edge, and some joints delaminated after quenches. Transport measurements show that the deformations correlate to Ic degradations, especially for the outer turns of pancakes. Microstructural studies reveal that the deformed (and cracked) edges are always the one that were slit during manufacturing. It appears that small, pre-existing micro-cracks on slit edges propagate after high-field tests. Study of individual strands of conductor on round core (CORCRTM ) cables demonstrated their steady improvements in the last few years. Overall cable current density, Je, has been greatly improved by replacement of 50 mum by 30 mum thick substrate in CCs and improved winding procedures cause no damage to the tapes. However, some degradation may appear after cables are bent and tested in high-field (20 T). It is found that inner layers are more vulnerable than outer layers. Winding angles and gaps strongly influence where degradations start. To understand the failure mechanisms and establish the limiting winding conditions for CORCRTM cables/wires, tapes were wound on different formers at different angles: 23°, 30°, 45° and 60°. For a 2 mm former diameter, the highest winding angle gives the least degradation while the other three are comparable. A major defect type introduced during winding is propagation of pre-existing edge (slitting) cracks, but some delamination under winding stress can also be seen. For the former with 2.54 mm in diameter, no propagations of pre-existing cracks or delaminations were observed after winding. Our studies of CCs made and tested in different ways has shown that further improvement of CC and of CORCRTM cables/wires can be made and also that some inherent features of the manufacture of CCs exert a strong influence on their service performance.

Animal breeding strategies can improve meat quality attributes within entire populations.

PubMed

Berry, D P; Conroy, S; Pabiou, T; Cromie, A R

2017-10-01

The contribution of animal breeding to changes in animal performance is well documented across a range of species. Once genetic variation in a trait exists, then breeding to improve the characteristics of that trait is possible, if so desired. Considerable genetic variation exists in a range of meat quality attributes across a range of species. The genetic variation that exists for meat quality is as large as observed for most performance traits; thus, within a well-structured breeding program, rapid genetic gain for meat quality could be possible. The rate of genetic gain can be augmented through the integration of DNA-based technologies into the breeding program; such DNA-based technologies should, however, be based on thousands of DNA markers dispersed across the entire genome. Genetic and genomic technologies can also have beneficial impact outside the farm gate as a tool to segregate carcasses or meat cuts based on expected meat quality features. Copyright © 2017 Elsevier Ltd. All rights reserved.

Extreme mobility in the Late Pleistocene? Comparing limb biomechanics among fossil Homo, varsity athletes and Holocene foragers.

PubMed

Shaw, Colin N; Stock, Jay T

2013-04-01

Descriptions of Pleistocene activity patterns often derive from comparisons of long bone diaphyseal robusticity across contemporaneous fossilized hominins. The purpose of this study is to augment existing understanding of Pleistocene hominin mobility patterns by interpreting fossil variation through comparisons with a) living human athletes with known activity patterns, and b) Holocene foragers where descriptions of group-level activity patterns are available. Relative tibial rigidity (midshaft tibial rigidity (J)/midshaft humeral rigidity (J)) was compared amongst Levantine and European Neandertals, Levantine and Upper Palaeolithic Homo sapiens, Holocene foragers and living human athletes and controls. Cross-country runners exhibit significantly (p<0.05) greater relative tibial rigidity compared with swimmers, and higher values compared with controls. In contrast, swimmers displayed significantly (p<0.05) lower relative tibial rigidity than both runners and controls. While variation exists among all Holocene H. sapiens, highly terrestrially mobile Later Stone Age (LSA) southern Africans and cross-country runners display the highest relative tibial rigidity, while maritime Andaman Islanders and swimmers display the lowest, with controls falling between. All fossil hominins displayed relative tibial rigidity that exceeded, or was similar to, the highly terrestrially mobile Later Stone Age southern Africans and modern human cross-country runners. The more extreme skeletal structure of most Neandertals and Levantine H. sapiens, as well as the odd Upper Palaeolithic individual, appears to reflect adaptation to intense and/or highly repetitive lower limb (relative to upper limb) loading. This loading may have been associated with bipedal travel, and appears to have been more strenuous than that encountered by even university varsity runners, and Holocene foragers with hunting grounds 2000-3000 square miles in size. Skeletal variation among the athletes and foraging groups is consistent with known or inferred activity profiles, which support the position that the Pleistocene remains reflect adaptation to extremely active and mobile lives. Copyright © 2013 Elsevier Ltd. All rights reserved.

Host Genetics and Environment Drive Divergent Responses of Two Resource Sharing Gall-Formers on Norway Spruce: A Common Garden Analysis.

PubMed

Axelsson, E Petter; Iason, Glenn R; Julkunen-Tiitto, Riitta; Whitham, Thomas G

2015-01-01

A central issue in the field of community genetics is the expectation that trait variation among genotypes play a defining role in structuring associated species and in forming community phenotypes. Quantifying the existence of such community phenotypes in two common garden environments also has important consequences for our understanding of gene-by-environment interactions at the community level. The existence of community phenotypes has not been evaluated in the crowns of boreal forest trees. In this study we address the influence of tree genetics on needle chemistry and genetic x environment interactions on two gall-inducing adelgid aphids (Adelges spp. and Sacchiphantes spp.) that share the same elongating bud/shoot niche. We examine the hypothesis that the canopies of different genotypes of Norway spruce (Picea abies L.) support different community phenotypes. Three patterns emerged. First, the two gallers show clear differences in their response to host genetics and environment. Whereas genetics significantly affected the abundance of Adelges spp. galls, Sacchiphantes spp. was predominately affected by the environment suggesting that the genetic influence is stronger in Adelges spp. Second, the among family variation in genetically controlled resistance was large, i.e. fullsib families differed as much as 10 fold in susceptibility towards Adelges spp. (0.57 to 6.2 galls/branch). Also, the distribution of chemical profiles was continuous, showing both overlap as well as examples of significant differences among fullsib families. Third, despite the predicted effects of host chemistry on galls, principal component analyses using 31 different phenolic substances showed only limited association with galls and a similarity test showed that trees with similar phenolic chemical characteristics, did not host more similar communities of gallers. Nonetheless, the large genetic variation in trait expression and clear differences in how community members respond to host genetics supports our hypothesis that the canopies of Norway spruce differ in their community phenotypes.

The Role of Mechanical Variance and Spatial Clustering on the Likelihood of Tumor Incidence and Growth

NASA Astrophysics Data System (ADS)

Mirzakhel, Zibah

When considering factors that contribute to cancer progression, modifications to both the biological and mechanical pathways play significant roles. However, less attention is placed on how the mechanical pathways can specifically contribute to cancerous behavior. Experimental studies have found that malignant cells are significantly softer than healthy, normal cells. In a tissue environment where healthy or malignant cells exist, a distribution of cell stiffness values is observed, with the mean values used to differentiate between these two populations. Rather than focus on the mean values, emphasis will be placed on the distribution, where instances of soft and stiff cells exist in the healthy tissue environment. Since cell deformability is a trait associated with cancer, the question arises as to whether the mechanical variation observed in healthy tissue cell stiffness distributions can influence any instances of tumor growth. To approach this, a 3D discrete model of cells is used, able to monitor and predict the behavior of individual cells while determining any instances of tumor growth in a healthy tissue. In addition to the mechanical variance, the spatial arrangement of cells will also be modeled, as cell interaction could further implicate any incidences of tumor-like malignant populations within the tissue. Results have shown that the likelihood of tumor incidence is driven by both by the increases in the mechanical variation in the distributions as well as larger clustering of cells that are mechanically similar, quantified primarily through higher proliferation rates of tumor-like soft cells. This can be observed though prominent negative shifts in the mean of the distribution, as it begins to transition and show instances of earlystage tumor growth. The model reveals the impact that both the mechanical variation and spatial arrangement of cells has on tumor progression, suggesting the use of these parameters as potential novel biomarkers. With a patient-specific approach in mind, the model may be applied for early-stage cancer detection, useful to establish a timeline on tumor progression.

Patterns of trust in sources of health information.

PubMed

Lawson, Rob; Forbes, Sarah; Williams, John

2011-01-21

To understand the different patterns of trust that exist regarding different sources of information about health issues. Data from a large national health lifestyles survey of New Zealanders was examined using a factor analysis of trust toward 24 health information sources (HIS). Differences in trust are compared across a range of demographic variables. Factor analysis identified six different groupings of health information. Variations in trust in sources for health information are identified by age, employment status, level of education, income, sex and ethnic group. Systematic variations exist in the trust that people report with respect to different sources of health information. Understanding these variations may assist policymakers and other agencies which are responsible for planning the dissemination of health information.

Rural hospital wages

PubMed Central

Hendricks, Ann M.

1989-01-01

Average fiscal year 1982 wages from 2,302 rural American hospitals were used to test for a gradient descending from hospitals in counties adjacent to metropolitan areas to those not adjacent. Considerable variation in the ratios of adjacent to nonadjacent averages existed. No statistically significant difference was found, however. Of greater importance in explaining relative wages within States were occupational mix, mix of part-time and full-time workers, case mix, presence of medical residencies, and location in a high-rent county within the State. Medicare already adjusts payments for only two of these variables. PMID:10313454

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

NASA Astrophysics Data System (ADS)

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 temporal variations of soil CO2 flux, CH4 uptake, and N2O emission. The soil water condition associated with soil hydraulic properties was also the important controlling factor of the spatial distributions of these gas fluxes.

Absence of diurnal variation of C-reactive protein concentrations in healthy human subjects

NASA Technical Reports Server (NTRS)

Meier-Ewert, H. K.; Ridker, P. M.; Rifai, N.; Price, N.; Dinges, D. F.; Mullington, J. M.

2001-01-01

BACKGROUND: The concentration of C-reactive protein (CRP) in otherwise healthy subjects has been shown to predict future risk of myocardial infarction and stroke. CRP is synthesized by the liver in response to interleukin-6, the serum concentration of which is subject to diurnal variation. METHODS: To examine the existence of a time-of-day effect for baseline CRP values, we determined CRP concentrations in hourly blood samples drawn from healthy subjects (10 males, 3 females; age range, 21-35 years) during a baseline day in a controlled environment (8 h of nighttime sleep). RESULTS: Overall CRP concentrations were low, with only three subjects having CRP concentrations >2 mg/L. Comparison of raw data showed stability of CRP concentrations throughout the 24 h studied. When compared with cutoff values of CRP quintile derived from population-based studies, misclassification of greater than one quintile did not occur as a result of diurnal variation in any of the subjects studied. Nonparametric ANOVA comparing different time points showed no significant differences for both raw and z-transformed data. Analysis for rhythmic diurnal variation using a method fitting a cosine curve to the group data was negative. CONCLUSIONS: Our data show that baseline CRP concentrations are not subject to time-of-day variation and thus help to explain why CRP concentrations are a better predictor of vascular risk than interleukin-6. Determination of CRP for cardiovascular risk prediction may be performed without concern for diurnal variation.

Geomorphic determinants of species composition of alpine tundra, Glacier National Park, U.S.A.

USGS Publications Warehouse

George P. Malanson,; Bengtson, Lindsey E.; Fagre, Daniel B.

2012-01-01

Because the distribution of alpine tundra is associated with spatially limited cold climates, global warming may threaten its local extent or existence. This notion has been challenged, however, based on observations of the diversity of alpine tundra in small areas primarily due to topographic variation. The importance of diversity in temperature or moisture conditions caused by topographic variation is an open question, and we extend this to geomorphology more generally. The extent to which geomorphic variation per se, based on relatively easily assessed indicators, can account for the variation in alpine tundra community composition is analyzed versus the inclusion of broad indicators of regional climate variation. Visual assessments of topography are quantified and reduced using principal components analysis (PCA). Observations of species cover are reduced using detrended correspondence analysis (DCA). A “best subsets” regression approach using the Akaike Information Criterion for selection of variables is compared to a simple stepwise regression with DCA scores as the dependent variable and scores on significant PCA axes plus more direct measures of topography as independent variables. Models with geographic coordinates (representing regional climate gradients) excluded explain almost as much variation in community composition as models with them included, although they are important contributors to the latter. The geomorphic variables in the model are those associated with local moisture differences such as snowbeds. The potential local variability of alpine tundra can be a buffer against climate change, but change in precipitation may be as important as change in temperature.

Incubator weaning in preterm infants and associated practice variation.

PubMed

Schneiderman, R; Kirkby, S; Turenne, W; Greenspan, J

2009-08-01

To evaluate the relationship of weight of preterm infants when first placed into an open crib with days to full oral feedings, growth velocity and length of stay (LOS), and to identify unwarranted variation in incubator weaning after adjusting for severity indices. A retrospective study using the ParadigmHealth neonatal database from 2003 to 2006 reviewed incubator weaning to an open crib in appropriate-for-gestational-age (AGA) infants from 22 to weeks gestation. Primary outcome measurements included days to full oral (PO) feeding, weight gain from open crib to discharge and length of stay. Models were severity adjusted. To understand hospital practice variation, we also used a regression model to estimate the weight at open crib for the top 10 volume hospitals. In all 2908 infants met the inclusion criteria for the study. Their mean weight at open crib was 1850 g. On average every additional 100 g an infant weighed at the open crib was associated with increased time to full PO feeding by 0.8 days, decreased weight gained per day by 1 gram and increased LOS by 0.9 days. For the top 10 volume hospitals, severity variables alone accounted for 9% of the variation in weight at open crib, whereas the hospital in which the baby was treated accounted for an additional 19% of the variation. Even after controlling for severity, significant practice variation exists in weaning to an open crib, leading to potential delays in achieving full-volume oral feeds, decreased growth velocity and prolonged LOS.

Between-year variation in population sex ratio increases with complexity of the breeding system in Hymenoptera.

PubMed

Kümmerli, Rolf; Keller, Laurent

2011-06-01

While adaptive adjustment of sex ratio in the function of colony kin structure and food availability commonly occurs in social Hymenoptera, long-term studies have revealed substantial unexplained between-year variation in sex ratio at the population level. In order to identify factors that contribute to increased between-year variation in population sex ratio, we conducted a comparative analysis across 47 Hymenoptera species differing in their breeding system. We found that between-year variation in population sex ratio steadily increased as one moved from solitary species, to primitively eusocial species, to single-queen eusocial species, to multiple-queen eusocial species. Specifically, between-year variation in population sex ratio was low (6.6% of total possible variation) in solitary species, which is consistent with the view that in solitary species, sex ratio can vary only in response to fluctuations in ecological factors such as food availability. In contrast, we found significantly higher (19.5%) between-year variation in population sex ratio in multiple-queen eusocial species, which supports the view that in these species, sex ratio can also fluctuate in response to temporal changes in social factors such as queen number and queen-worker control over sex ratio, as well as factors influencing caste determination. The simultaneous adjustment of sex ratio in response to temporal fluctuations in ecological and social factors seems to preclude the existence of a single sex ratio optimum. The absence of such an optimum may reflect an additional cost associated with the evolution of complex breeding systems in Hymenoptera societies.

Temporal distribution of deaths in cancer patients during the day in different settings.

PubMed

Gonçalves, José Ferraz; Fonseca, Eugénia; Alvarenga, Margarida; Morais, Maria Rosa

2005-06-01

All living organisms perform their functions normally according to circadian rhythms. Certain diseases, such as ischemic heart disease and asthma, produce symptoms that are distributed during the day in a nonrandom fashion. Chronomodulated therapy with some regimens of chemotherapy and other drugs produce better results than traditional schedules. Even death is not evenly distributed during the day. Significant differences in the time of death through the day could influence the work planning and care activities. To determine whether timing of death from a population of cancer patients admitted at our Oncology Institute varied during the day and according to different settings: at home (H), at the palliative care unit (PCU), and at other services (OS) of the hospital. Comparing the timing of deaths from different settings can give some clues about the possible existence of a circadian rhythm and the influence of external circumstances in the time of death of cancer patients. We conducted a retrospective study of the records of time of death at the different settings. The study involved 772 patients from the PCU and 997 from OS who died between May 25, 1996, and May 24, 2000, and 347 patients who died at H between April 1, 1999, and December 31, 2001. A statistically significant difference was found in the distribution of time of death in patients at the PCU (p <.001), but not at OS or at H. There were two peaks between 08:00 and 10:00 and between 00:00 and 02:00, and one trough between 04:00 and 08:00. This suggests that a temporal variation occurs in the time of death of cancer patients dying in the PCU, but not in other settings. The clinical relevance of the results obtained in this study would depend on the amplitude of the eventual variation detected in the number of deaths during the day. Therefore, although there was a statistically significant variation at the time of death during the day, its amplitude is not high enough to make it clinically significant. The differences observed among the various settings suggest that, even if circadian rhythms exist at the time of death in cancer patients, external factors can overcome these rhythms.

Analysis of Inter- and Intra-individual Variation in Foraging Habits of the Endangered Hawaiian Petrel Using Stables Isotopes

NASA Astrophysics Data System (ADS)

Morra, K. E.; Ostrom, P. H.; Wiley, A. E.; James, H. F.; Stricker, C. A.; Gandhi, H.

2014-12-01

Stable isotope analysis of the endangered Hawaiian petrel's (Pterodroma sandwichensis, HAPE) feathers provides otherwise intractable information regarding non-breeding season foraging habits. Adult HAPE spend 3.5-6 months at sea during the non-breeding season, at which time they sequentially molt their flight feathers. Because feathers are metabolically inert once synthesized, they capture isotopic signals while they are grown, providing an opportunity to study foraging habits over time. Here we use stable hydrogen (δD), carbon (δ13C) and nitrogen (δ15N) isotopes to assess variation in foraging habits within and between individuals, and among four breeding colonies. δD is an indicator of prevalence of fish vs. invertebrates in the diet. In one analysis, we observed large variation in feather δD (125‰), with adults from Maui and Kauai having significantly higher δD values than corresponding hatch-year birds, indicating significant dietary differences between age groups. In a second analysis, we utilized δ13C and δ15N of Hawaii, Maui and Lanai adults, values which vary with trophic level and also at the base of the food web across HAPE's foraging range, potentially revealing information about feeding location, as well as diet. Furthermore, because the sequence of molt is known, we are able to determine whether individual foraging specialization (continued use of the same foraging behavior over time) exists in this species. To do this, we analyzed two primary feathers, P1 and P6, which reflect the beginning and the middle of the non-breeding season, respectively. We did not find significant differences in δ13C or δ15N between P1 and P6, suggesting consistent foraging habits within individuals over time. This provides evidence that individual foraging specialization exists within these populations. Analysis of a secondary feather grown late in the molt sequence would further illuminate the extent of foraging specialization. Finally, δ15N differs significantly between Hawaii and Maui adults, suggesting foraging segregation between these two populations. HAPE may be sensitive to changes in prey availability, given evidence of foraging specialization. However, conserving HAPE populations with apparently different foraging habits may be critical to preserve ecological diversity within the species.

Stochastic Nonlinear Response of Woven CMCs

NASA Technical Reports Server (NTRS)

Kuang, C. Liu; Arnold, Steven M.

2013-01-01

It is well known that failure of a material is a locally driven event. In the case of ceramic matrix composites (CMCs), significant variations in the microstructure of the composite exist and their significance on both deformation and life response need to be assessed. Examples of these variations include changes in the fiber tow shape, tow shifting/nesting and voids within and between tows. In the present work, the influence of scale specific architectural features of woven ceramic composite are examined stochastically at both the macroscale (woven repeating unit cell (RUC)) and structural scale (idealized using multiple RUCs). The recently developed MultiScale Generalized Method of Cells methodology is used to determine the overall deformation response, proportional elastic limit (first matrix cracking), and failure under tensile loading conditions and associated probability distribution functions. Prior results showed that the most critical architectural parameter to account for is weave void shape and content with other parameters being less in severity. Current results show that statistically only the post-elastic limit region (secondary hardening modulus and ultimate tensile strength) is impacted by local uncertainties both at the macro and structural level.

Neonatal extravasation injury: prevention and management in Australia and New Zealand-a survey of current practice.

PubMed

Restieaux, Matthew; Maw, Andrew; Broadbent, Roland; Jackson, Pam; Barker, David; Wheeler, Ben

2013-03-11

Extravasation injury remains an important cause of iatrogenic injury in neonatal intensive care. This study aims to describe the current approach to extravasation injury (EI) prevention and management in Neonatal Intensive Care Units (NICUs) in Australia and New Zealand. A literature review regarding extravasation injury in the newborn was carried out to inform questionnaire design. An internet-based survey was then conducted with the clinical directors of the 27 tertiary NICUs in Australia and New Zealand. The survey received a 96% response rate. Approximately two thirds of Australian and New Zealand NICUs have written protocols for prevention and management of extravasation injury. Considerable practice variation was seen for both prevention and treatment of EI. 92% of units had experienced cases of significant EI. Australian and New Zealand tertiary neonatal units clearly recognise EI as an important cause of iatrogenic morbidity and mortality. Significant variation still exists among units with regards to guidelines for both prevention and management of EI. We recommend that neonatal staff should remain vigilant, ensuring that guidelines for the prevention and treatment of EI are available, and rigorously followed.

Strongly nonlinear parabolic variational inequalities

PubMed Central

Browder, Felix E.; Brézis, Haim

1980-01-01

An existence and uniqueness result is established for a general class of variational inequalities for parabolic partial differential equations of the form ∂u/∂t + A(u) + g(u) = f with g nondecreasing but satisfying no growth condition. The proof is based upon a type of compactness result for solutions of variational inequalities that should find a variety of other applications. PMID:16592776

Evaluating the Policies that Lead to Substantial Tuition Variation at Public Land-Grant Universities

ERIC Educational Resources Information Center

Burgess, Brent

2011-01-01

The aim of this study is to evaluate the current state of, and the causes for, the substantial variation in the tuition rates of America's land-grant universities. This aim was pursued with the objective of trying to identify consistent and revealing policies and external characteristics related to the high level of variation that exists among…

Predictive models for radial sap flux variation in coniferous, diffuse-porous and ring-porous temperate trees

Treesearch

Aaron B. Berdanier; Chelcy F. Miniat; James S. Clark

2016-01-01

Accurately scaling sap flux observations to tree or stand levels requires accounting for variation in sap flux between wood types and by depth into the tree. However, existing models for radial variation in axial sap flux are rarely used because they are difficult to implement, there is uncertainty about their predictive ability and calibration measurements...

Variational submanifolds of Euclidean spaces

NASA Astrophysics Data System (ADS)

Krupka, D.; Urban, Z.; Volná, J.

2018-03-01

Systems of ordinary differential equations (or dynamical forms in Lagrangian mechanics), induced by embeddings of smooth fibered manifolds over one-dimensional basis, are considered in the class of variational equations. For a given non-variational system, conditions assuring variationality (the Helmholtz conditions) of the induced system with respect to a submanifold of a Euclidean space are studied, and the problem of existence of these "variational submanifolds" is formulated in general and solved for second-order systems. The variational sequence theory on sheaves of differential forms is employed as a main tool for the analysis of local and global aspects (variationality and variational triviality). The theory is illustrated by examples of holonomic constraints (submanifolds of a configuration Euclidean space) which are variational submanifolds in geometry and mechanics.

Diurnal Variation of Sweet Taste Recognition Thresholds Is Absent in Overweight and Obese Humans

PubMed Central

Sanematsu, Keisuke; Nakamura, Yuki; Nomura, Masatoshi; Shigemura, Noriatsu; Ninomiya, Yuzo

2018-01-01

Sweet taste thresholds are positively related to plasma leptin levels in normal weight humans: both show parallel diurnal variations and associations with postprandial glucose and insulin rises. Here, we tested whether this relationship also exists in overweight and obese (OW/Ob) individuals with hyperleptinemia. We tested 36 Japanese OW/Ob subjects (body mass index (BMI) > 25 kg/m2) for recognition thresholds for various taste stimuli at seven different time points from 8:00 a.m. to 10:00 p.m. using the staircase methodology, and measured plasma leptin, insulin, and blood glucose levels before each taste threshold measurement. We also used the homeostatic model assessment of insulin resistance (HOMA-IR) to evaluate insulin resistance. The results demonstrated that, unlike normal weight subjects, OW/Ob subjects showed no significant diurnal variations in the recognition thresholds for sweet stimuli but exhibited negative associations between the diurnal variations of both leptin and sweet recognition thresholds and the HOMA-IR scores. These findings suggest that in OW/Ob subjects, the basal leptin levels (~20 ng/mL) may already exceed leptin’s effective concentration for the modulation of sweet sensitivity and that this leptin resistance-based attenuation of the diurnal variations of the sweet taste recognition thresholds may also be indirectly linked to insulin resistance in OW/Ob subjects. PMID:29498693

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

PubMed

Brazzola, Gregory; Chèvre, Nathalie; Wedekind, Claus

2014-11-01

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

Intra- and Inter-Fractional Variation Prediction of Lung Tumors Using Fuzzy Deep Learning

PubMed Central

Park, Seonyeong; Lee, Suk Jin; Weiss, Elisabeth

2016-01-01

Tumor movements should be accurately predicted to improve delivery accuracy and reduce unnecessary radiation exposure to healthy tissue during radiotherapy. The tumor movements pertaining to respiration are divided into intra-fractional variation occurring in a single treatment session and inter-fractional variation arising between different sessions. Most studies of patients’ respiration movements deal with intra-fractional variation. Previous studies on inter-fractional variation are hardly mathematized and cannot predict movements well due to inconstant variation. Moreover, the computation time of the prediction should be reduced. To overcome these limitations, we propose a new predictor for intra- and inter-fractional data variation, called intra- and inter-fraction fuzzy deep learning (IIFDL), where FDL, equipped with breathing clustering, predicts the movement accurately and decreases the computation time. Through the experimental results, we validated that the IIFDL improved root-mean-square error (RMSE) by 29.98% and prediction overshoot by 70.93%, compared with existing methods. The results also showed that the IIFDL enhanced the average RMSE and overshoot by 59.73% and 83.27%, respectively. In addition, the average computation time of IIFDL was 1.54 ms for both intra- and inter-fractional variation, which was much smaller than the existing methods. Therefore, the proposed IIFDL might achieve real-time estimation as well as better tracking techniques in radiotherapy. PMID:27170914

Effectiveness of the anaesthetic MS-222 in gilthead seabream, Sparus aurata: effect of feeding time and day-night variations in plasma MS-222 concentration and GST activity.

PubMed

Vera, L M; Montoya, A; Sánchez-Vázquez, F J

2013-02-17

Feeding time is a potent zeitgeber capable of synchronising behavioural and physiological daily rhythms in fish. However, the effect of feeding time on the daily rhythm of drugs toxicity and/or effectiveness remains unexplored to date. In this paper we investigated the day/night variations in the effectiveness of an anaesthetic commonly used in fish (Tricaine, MS-222) in a teleost of great chronobiological and aquaculture interest (gilthead seabream). To this end, fish were kept under LD 12:12 and fed at mid-light (ML), mid-darkness (MD) or random times (RD). The time needed to induce anaesthesia (reduction of locomotor activity) during MS-222 exposure (65 mg/L) as well as the recovery period were investigated at ML and MD in the three experimental groups using specialised video tracking software. In addition, daily rhythms of GST activity in the liver (as an indicator of detoxification processes) and plasma MS-222 concentration (related to uptake) were determined. The results revealed that MS-222 effectiveness in the ML group was higher during the day than at night (significant reduction of activity after 3 min vs. 5 min) whereas in the MD group, the daily variation of MS-222 effectiveness was inverted (significant reduction of activity after 7 min at ML vs. 2 min at MD), suggesting that feeding time can shift the day-night variations in the effectiveness of MS-222. Hepatic GST also seemed to be affected by feeding time: in fish fed at MD or RD this enzyme activity showed significant differences during the day, and the highest levels were found at different times of the day in each group. Plasma MS-222 concentrations were higher at ML (142.4±12.8 ng/ml) than at MD (96.3±10.9 ng/ml) (t-Student, p<0.05). These results suggest that the daily variation in MS-222 concentration following exposure might be involved, among other factors, in the existence of day-night variations in the effectiveness of this anaesthetic. Furthermore, manipulation of the feeding schedule can be used to modify the daily variations in MS-222 effectiveness, which has basic as well applied implications for optimising anaesthesia protocols in fish aquaculture. Copyright © 2013 Elsevier Inc. All rights reserved.

Minimizing losses by variational counter-diabatic driving

NASA Astrophysics Data System (ADS)

Sels, Dries; Polkovnikov, Anatoli

Despite the time-reversal symmetry of the microscopic dynamics of isolated systems, losses are ubiquitous in any process that tries to manipulate them. Whether it's the heat produced in a car engine or the decoherence of a qubit, all losses arise from our lack of control on the microscopic degrees of freedom of the system. Counter-diabatic driving protocols were proposed as a means to do fast changes in the Hamiltonian without exciting transitions. Such driving in principle allows one to realize arbitrarily fast annealing protocols or implement fast dissipationless driving, circumventing standard adiabatic limitations requiring infinitesimally slow rates. These ideas were tested and used both experimentally and theoretically in small systems, but in larger chaotic systems it is known that exact counter-diabatic protocols do not exist. Here we will present a simple variational approach allowing one to find best physical counter-diabatic protocols. We will show that, while they do not get rid of all transitions, the variational protocols are able to significantly reduce the induced fluctuations in the system. D.S. acknowledges support by the FWO.

High-resolution determination of the stress in individual interconnect lines and the variation due to electromigration

NASA Astrophysics Data System (ADS)

Ma, Qing; Chiras, S.; Clarke, D. R.; Suo, Z.

1995-08-01

Large tensile stresses usually exist in metallic interconnect lines on silicon substrates as a result of thermal mismatch. When a current is subsequently passed any divergence of atomic flux can create superimposed stress variations along the line. Together, these stresses can significantly influence the growth of voids and therefore affect interconnect reliability. In this work, a high-resolution (˜2 μm) optical spectroscopy method has been used to measure the localized stresses around passivated aluminum lines on a silicon wafer, both as-fabricated and after electromigration testing. The method is based on the piezospectroscopic properties of silicon, specifically the frequency shift of the Raman line at 520 R cm-1. By focusing a laser beam at points adjacent to the aluminum lines, the Raman signal was excited and collected. The stresses in the aluminum lines can then be derived from the stresses in the silicon using finite element methods. Large variations of stress along an electromigration-tested line were observed and compared to a theoretical model based on differences in effective diffusivities from grain to grain in a polycrystalline interconnect line.

Research on the optimization of air quality monitoring station layout based on spatial grid statistical analysis method.

PubMed

Li, Tianxin; Zhou, Xing Chen; Ikhumhen, Harrison Odion; Difei, An

2018-05-01

In recent years, with the significant increase in urban development, it has become necessary to optimize the current air monitoring stations to reflect the quality of air in the environment. Highlighting the spatial representation of some air monitoring stations using Beijing's regional air monitoring station data from 2012 to 2014, the monthly mean particulate matter concentration (PM10) in the region was calculated and through the IDW interpolation method and spatial grid statistical method using GIS, the spatial distribution of PM10 concentration in the whole region was deduced. The spatial distribution variation of districts in Beijing using the gridding model was performed, and through the 3-year spatial analysis, PM10 concentration data including the variation and spatial overlay (1.5 km × 1.5 km cell resolution grid), the spatial distribution result obtained showed that the total PM10 concentration frequency variation exceeded the standard. It is very important to optimize the layout of the existing air monitoring stations by combining the concentration distribution of air pollutants with the spatial region using GIS.

The variation of the ground electric field associated with the Mei-Nung earthquake on Feb. 6, 2016

NASA Astrophysics Data System (ADS)

Bing-Chih Chen, Alfred; Yeh, Er-Chun; Chuang, Chia-Wen

2017-04-01

Recent studies show that a strong coupling exists between lithosphere, atmosphere and extending up to the ionosphere. Natural phenomena on the ground surface such as oceans variation, volcanic and seismic activities such as earthquakes, and lightning possibly generate significant impacts at ionosphere immediately by electrodynamic processes. The electric field near the ground is one of the potential quantities to explore this coupling process, especially caused by earthquake. Unfortunately, thunderstorm, dust storm or human activities also affect the measured electric field at ground. To investigate the feasibility of a network to monitor the variation of the ground electric field driven by the lightning and earthquake, a filed mill has been deployed in the NCKU campus since Dec. 2015, and luckily experienced the earthquake with a moment magnitude of 6.4 struck 28 km on 6 Feb. 2016. The recorded ground electric field deceased steadily since 1.5 days before the earthquake, and returned to normal level gradually. Moreover, this special feature can not be identified in the other period of the field test. The detail analysis is reported in this presentation.

Annual variation of gravity-wave activity at middle and high latitudes in a high-resolution GCM

NASA Astrophysics Data System (ADS)

Becker, E.

2017-12-01

A high-resolution version of the Kuehlungsborn Mechanistic general Circulation Model (KMCM) with resolved gravity waves (GWs) is employed to analyze the annual variation of GW activity in both hemispheres at middle and high latitudes. The geographical distributions of GW hotspots in the winter stratosphere are consistent with existing satellite data. Vertical profiles up to the lower thermosphere agree with ground-based measurements for both season. The model confirms the semi-annual variation of GW energy in the upper mesosphere that was found previously in radar-measurements in the northern hemisphere Furthermore, the GW potential energy per unit mass during winter shows two maxima, one around 50-70 km and one around 80-100 km. We interpret the upper maximum as a result of secondary GWs that are generated in the stratopause region due to the intermittent body forces of primary GWs. In a recent study we showed that these secondary GWs produce a significant eastward drag in the mesopause region during austral winter. This mechanism is found to be important in the northern winter as well.

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

NASA Astrophysics Data System (ADS)

Dzambo, Andrew M.; Turner, David D.

2016-10-01

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

Improvement of isotope-based climate reconstructions in Patagonia through a better understanding of climate influences on isotopic fractionation in tree rings

NASA Astrophysics Data System (ADS)

Lavergne, Aliénor; Daux, Valérie; Villalba, Ricardo; Pierre, Monique; Stievenard, Michel; Srur, Ana Marina

2017-02-01

Very few studies of stable isotopes exist across the Andes in South America. This study is the first presenting annually resolved chronologies of both δ18 O and δ13 C in Nothofagus pumilio and Fitzroya cupressoides trees from Northern Patagonia. Interannual variability in δ18 O and δ13 C was assessed over the period 1952-2011. Based on these chronologies, we determined the primary climatic controls on stable isotopes and tree physiological responses to changes in atmospheric CO2 concentrations (ca), temperature and humidity. Changes in specific intrinsic water use efficiency (iWUE) were inferred from variations in δ13 C whereas the effects of CO2 increase on stomatal conductance were explored using δ18 O. Over the 60-year period, iWUE increased significantly (by ca. 25%) in coincidence with the rise of ca. The two species appear to have different strategies of gas-exchange. Whereas iWUE variations were likely driven by both stomatal conductance and photosynthetic assimilation rates in F. cupressoides, they were largely related to stomatal conductance in N. pumilio. After removing the low-frequency trends related to increasing ca, significant relationships between δ13 C and summer temperatures were recorded for both species. However, δ13 C variations in F. cupressoides were more strongly influenced by summer temperatures than in N. pumilio. Our results advocate for an indirect effect of summer temperatures on stable isotope ratios, which is mostly influenced by sunlight radiation in F. cupressoides and relative humidity/soil moisture in N. pumilio. δ13 C variations in F. cupressoides were spatially correlated to a large area south of 35°S in southern South America. These promising results encourage the use of δ13 C variations in F. cupressoides for reconstructing past variations in temperature and large-scale circulation indexes such as the Southern Annular Mode (SAM) in the Southern Hemisphere.

Variation in practice and resource utilization associated with the diagnosis and management of appendicitis at freestanding children's hospitals: implications for value-based comparative analysis.

PubMed

Rice-Townsend, Samuel; Barnes, Jeff N; Hall, Matthew; Baxter, Jessica L; Rangel, Shawn J

2014-06-01

To characterize the scope and magnitude of practice variation associated with the diagnosis and treatment of appendicitis at freestanding children's hospitals. Variation in care has been associated with poor outcomes and is believed to be a key driver of excess health care spending. Retrospective cohort study of 13,328 patients treated with appendicitis at 34 children's hospitals (9/2010-9/2011). Patients were divided into complicated and uncomplicated cohorts and examined for interhospital variation in the use of diagnostic imaging (computed tomography or ultrasonography), laboratory tests, parenteral nutrition (PN), peripherally inserted central catheters (PICC), and hospital cost. The number and distribution of statistical outliers were calculated for all measures. Significant variation was found for all measures, including a 3.5-fold difference in preoperative imaging (aggregate rate: 49.0%, range across hospitals: 21.2%-73.5%, P < 0.001) and a 5-fold difference in preoperative laboratory utilization (aggregate median: 2 tests/encounter, range: 1-5 tests/encounter, P < 0.001). For patients with complicated appendicitis, we characterized a 12-fold difference in postoperative imaging (aggregate rate: 19.4%, range: 4.9%-61.6%, P < 0.001), a 48-fold difference in PICC lines (aggregate rate: 18.9%, range: 1.7%-81.8%, P < 0.001), and a 100-fold difference in PN utilization (aggregate rate: 9.3%, range: 0.4%-42.0%, P < 0.001). Median hospital cost differed 4-fold for patients with uncomplicated disease (aggregate median: $6804, range: $4200-$16,796, P < 0.001) and 4.6-fold for patients with complicated disease (aggregate median: $13,138, range: $5419-$24,779, P < 0.001). Statistical outliers on the basis of high and low utilization were identified for all measures. Significant variation exists in practice, resource utilization, and treatment-related cost associated with the management of appendicitis at freestanding children's hospitals. Value-based measures are needed for benchmarking and to prioritize collaborative quality improvement efforts.

SU-C-202-02: A Comprehensive Evaluation of Adaptive Daily Planning for Cervical Cancer HDR Brachytherapy

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

Meerschaert, R; Paul, A; Zhuang, L

Purpose: To evaluate adaptive daily planning for cervical cancer patients who underwent high-dose-rate intra-cavitary brachytherapy (HDR-ICBT). Methods: This study included 22 cervical cancer patients who underwent 5 fractions of HDR ICBT. Regions of interest (ROIs) including high-risk clinical tumor volume (HR-CTV) and organs-at-risk (OARs) were manually contoured on daily CT images. All patients were treated with adaptive daily plans, which involved ROI delineation and dose optimization at each treatment fraction. Single treatment plans were retrospectively generated by applying the first treatment fraction’s dwell times adjusted for decay and dwell positions of the applicator to subsequent treatment fractions. Various existing similaritymore » metrics were calculated for the ROIs to quantify interfractional organ variations. A novel similarity score (JRARM) was established, which combined both volumetric overlap metrics (DSC, JSC, and RVD) and distance metrics (ASD, MSD, and RMSD). Linear regression was performed to determine a relationship between inter-fractional organ variations of various similarity metrics and D2cc variations from both plans. Wilcoxon Signed Rank Tests were used to assess adaptive daily plans and single plans by comparing EQD2 D2cc (α/β=3) for OARs. Results: For inter-fractional organ variations, the sigmoid demonstrated the greatest variations based on the JRARM and DSC similarity metrics. Comparisons between paired ROIs showed differences in JRARM scores and DSCs at each treatment fraction. RVD, MSD, and RMSD were found to be significantly correlated to D2cc variations for bladder and sigmoid. The comparison between plans found that adaptive daily planning provided lower EQD2 D2cc of OARs than single planning, specifically for the sigmoid (p=0.015). Conclusion: Substantial inter-fractional organ motion can occur during HDR-BT, which may significantly affect D2cc of OARs. Adaptive daily planning provides improved dose sparing for OARs compared to single planning.« less

Spatiotemporal variation of radon and carbon dioxide concentrations in an underground quarry: coupled processes of natural ventilation, barometric pumping and internal mixing.

PubMed

Perrier, Frédéric; Richon, Patrick

2010-04-01

Radon-222 and carbon dioxide concentrations have been measured during several years at several points in the atmosphere of an underground limestone quarry located at a depth of 18 m in Vincennes, near Paris, France. Both concentrations showed a seasonal cycle. Radon concentration varied from 1200 to 2000 Bq m(-3) in summer to about 800-1400 Bq m(-3) in winter, indicating winter ventilation rates varying from 0.6 to 2.5 x 10(-6) s(-1). Carbon dioxide concentration varied from 0.9 to 1.0% in summer, to about 0.1-0.3% in winter. Radon concentration can be corrected for natural ventilation using temperature measurements. The obtained model also accounts for the measured seasonal variation of carbon dioxide. After correction, radon concentrations still exhibit significant temporal variation, mostly associated with the variation of atmospheric pressure, with coupling coefficients varying from -7 to -26 Bq m(-3) hPa(-1). This variation can be accounted for using a barometric pumping model, coupled with natural ventilation in winter, and including internal mixing as well. After correction, radon concentrations exhibit residual temporal variation, poorly correlated between different points, with standard deviations varying from 3 to 6%. This study shows that temporal variation of radon concentrations in underground cavities can be understood to a satisfactory level of detail using non-linear and time-dependent modelling. It is important to understand the temporal variation of radon concentrations and the limitations in their modelling to monitor the properties of natural or artificial underground settings, and to be able to assess the existence of new processes, for example associated with the preparatory phases of volcanic eruptions or earthquakes. Copyright 2009 Elsevier Ltd. All rights reserved.

Random Positional Variation Among the Skull, Mandible, and Cervical Spine With Treatment Progression During Head-and-Neck Radiotherapy

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

Ahn, Peter H.; Ahn, Andrew I.; Lee, C. Joe

2009-02-01

Purpose: With 54{sup o} of freedom from the skull to mandible to C7, ensuring adequate immobilization for head-and-neck radiotherapy (RT) is complex. We quantify variations in skull, mandible, and cervical spine movement between RT sessions. Methods and Materials: Twenty-three sequential head-and-neck RT patients underwent serial computed tomography. Patients underwent planned rescanning at 11, 22, and 33 fractions for a total of 93 scans. Coordinates of multiple bony elements of the skull, mandible, and cervical spine were used to calculate rotational and translational changes of bony anatomy compared with the original planning scan. Results: Mean translational and rotational variations on rescanningmore » were negligible, but showed a wide range. Changes in scoliosis and lordosis of the cervical spine between fractions showed similar variability. There was no correlation between positional variation and fraction number and no strong correlation with weight loss or skin separation. Semi-independent rotational and translation movement of the skull in relation to the lower cervical spine was shown. Positioning variability measured by means of vector displacement was largest in the mandible and lower cervical spine. Conclusions: Although only small overall variations in position between head-and-neck RT sessions exist on average, there is significant random variation in patient positioning of the skull, mandible, and cervical spine elements. Such variation is accentuated in the mandible and lower cervical spine. These random semirigid variations in positioning of the skull and spine point to a need for improved immobilization and/or confirmation of patient positioning in RT of the head and neck.« less

Corallite skeletal morphological variation in Hawaiian Porites lobata

NASA Astrophysics Data System (ADS)

Tisthammer, Kaho H.; Richmond, Robert H.

2018-06-01

Due to their high morphological plasticity and complex evolutionary history, the species boundaries of many reef-building corals are poorly understood. The skeletal structures of corals have traditionally been used for species identification, but these structures can be highly variable, and currently we lack knowledge regarding the extent of morphological variation within species. Porites species are notorious for their taxonomic difficulties, both morphologically and genetically, and currently there are several unresolved species complexes in the Pacific. Despite its ubiquitous presence and broad use in coral research, Porites lobata belongs to one such unresolved species complex. To understand the degree of intraspecific variation in skeletal morphology, 120 corallites from the Hawaiian P. lobata were examined. A subset of samples from two genetically differentiated populations from contrasting high- and low-stress environments in Maunalua Bay, Hawaii, were then quantitatively analyzed using multivariate morphometrics. Our observations revealed high intraspecific variation in corallite morphology, as well as significant morphological differences between the two populations of P. lobata. Additionally, significant correlation was found between the morphological and genetic distances calculated from approximately 18,000 loci generated from restriction site-associated DNA sequencing. The unique morphological characters observed from the genetically differentiated population under environmental stress suggest that these characters may have adaptive values, but how such traits relate to fitness and how much plasticity they can exhibit remain to be determined by future studies. Relatively simple morphometric analyses used in our study can be useful in clarifying the existing ambiguity in skeletal architecture, thus contributing to resolving species issues in corals.

Lithologically controlled detachment strength and steady state since 10 Ma: Exploring the Alpine wedge using critical taper analysis combined with low-temperature thermochronometry

NASA Astrophysics Data System (ADS)

von Hagke, Christoph; Oncken, Onno; Ortner, Hugo; Cederbom, Charlotte

2014-05-01

Although evidence for weak detachments underlying foreland thrust belts exists, very little is known about the lateral variations in effective strength, as well as the geological nature of such variations. Using critical taper analysis, we show that a detailed and systematic measurement of surface slope of the Central European Alps reveals variations in strength along the detachment, based on the argument that the Alps are close to the critical state. We show that the basal detachment is very weak near the deformation front but strengthens towards the hinterland. These changes in detachment strength coincide with changes of detachment lithology in the hangingwall and footwall respectively, emphasizing the dominant role of weak shales. The very low strength values we find in shales in the frontal part of the alpine sole detachment are caused partly by slightly elevated pore pressures but may also require additional mechanisms of dynamic weakening. Using the constraints on the present day alpine taper, we investigate the change in taper through time. To this end, we produced new apatite fission track and apatite (U-Th)/He data from the Alpine orogenic front, the Austrian Subalpine Molasse. We combine this data set with existing thermochronometry, and reconstruct the Central Alpine pro-wedge geometry at 10 Ma. We show that the taper of the Central Alps has not changed significantly and presumably remained close to kinematic and mass flux steady state since then. This indicates a feedback between ongoing shortening and erosion at low rates during the Late Neogene to present.

The significance of large variations in oil properties of the Dai Hung field, Vietnam

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

Behrenbruch, P.; Du, P.Q.

1995-10-01

The Dai Hung Oil field, offshore Vietnam, is comprised of a complex subsurface structure containing stacked reservoir sequences typically found in many other Southeast Asian fields. Combined with areal fault compartmentalization, this situation has led to the observed, large variations in oil properties. Furthermore, the depositional environment in terms of burial history has created a unique overpressure situation which also had an affect, particularly on the crude saturation conditions of individual reservoirs. For commercial and technical reasons, this situation required a detailed analysis, both in terms of variation in crude assay and live oil properties. For whole crude properties: gravity,more » K factor, wax content and pour point-graphs were drawn up using a large data base of worldwide crudes against which the Dai Hung data could be validated. In case of PVT properties (bubble point and formation volume factor) existing industry correlations were examined. It could be concluded that the sweet, medium gravity and moderately waxy Dai Hung crude has whole crude properties which are comparable to other, similar crudes. The general framework of crude properties established is suitable to type other crudes, even if limited information is available. Of the existing PVT correlations tested, it was found that Standing`s correlation for the oil formation volume factor and the Kartoatmodjo-Schmidt correlation for the bubble point fitted the Dai Hung crude data the best. For the lower shrinkage Dai Hung crudes the Malaysian oil formation volume factor correlation by Omar-Todd gave the best data fit.« less

Robust Radar Emitter Recognition Based on the Three-Dimensional Distribution Feature and Transfer Learning

PubMed Central

Yang, Zhutian; Qiu, Wei; Sun, Hongjian; Nallanathan, Arumugam

2016-01-01

Due to the increasing complexity of electromagnetic signals, there exists a significant challenge for radar emitter signal recognition. To address this challenge, multi-component radar emitter recognition under a complicated noise environment is studied in this paper. A novel radar emitter recognition approach based on the three-dimensional distribution feature and transfer learning is proposed. The cubic feature for the time-frequency-energy distribution is proposed to describe the intra-pulse modulation information of radar emitters. Furthermore, the feature is reconstructed by using transfer learning in order to obtain the robust feature against signal noise rate (SNR) variation. Last, but not the least, the relevance vector machine is used to classify radar emitter signals. Simulations demonstrate that the approach proposed in this paper has better performances in accuracy and robustness than existing approaches. PMID:26927111

Rotorcraft control system design for uncertain vehicle dynamics using quantitative feedback theory

NASA Technical Reports Server (NTRS)

Hess, R. A.

1994-01-01

Quantitative Feedback Theory describes a frequency-domain technique for the design of multi-input, multi-output control systems which must meet time or frequency domain performance criteria when specified uncertainty exists in the linear description of the vehicle dynamics. This theory is applied to the design of the longitudinal flight control system for a linear model of the BO-105C rotorcraft. Uncertainty in the vehicle model is due to the variation in the vehicle dynamics over a range of airspeeds from 0-100 kts. For purposes of exposition, the vehicle description contains no rotor or actuator dynamics. The design example indicates the manner in which significant uncertainty exists in the vehicle model. The advantage of using a sequential loop closure technique to reduce the cost of feedback is demonstrated by example.

Robust Radar Emitter Recognition Based on the Three-Dimensional Distribution Feature and Transfer Learning.

PubMed

Yang, Zhutian; Qiu, Wei; Sun, Hongjian; Nallanathan, Arumugam

2016-02-25

Due to the increasing complexity of electromagnetic signals, there exists a significant challenge for radar emitter signal recognition. To address this challenge, multi-component radar emitter recognition under a complicated noise environment is studied in this paper. A novel radar emitter recognition approach based on the three-dimensional distribution feature and transfer learning is proposed. The cubic feature for the time-frequency-energy distribution is proposed to describe the intra-pulse modulation information of radar emitters. Furthermore, the feature is reconstructed by using transfer learning in order to obtain the robust feature against signal noise rate (SNR) variation. Last, but not the least, the relevance vector machine is used to classify radar emitter signals. Simulations demonstrate that the approach proposed in this paper has better performances in accuracy and robustness than existing approaches.

Evaluation of simulation motion fidelity criteria in the vertical and directional axes

NASA Technical Reports Server (NTRS)

Schroeder, Jeffery A.

1993-01-01

An evaluation of existing motion fidelity criteria was conducted on the NASA Ames Vertical Motion Simulator. Experienced test pilots flew single-axis repositioning tasks in both the vertical and the directional axes. Using a first-order approximation of a hovering helicopter, tasks were flown with variations only in the filters that attenuate the commands to the simulator motion system. These filters had second-order high-pass characteristics, and the variations were made in the filter gain and natural frequency. The variations spanned motion response characteristics from nearly full math-model motion to fixed-base. Between configurations, pilots recalibrated their motion response perception by flying the task with full motion. Pilots subjectively rated the motion fidelity of subsequent configurations relative to this full motion case, which was considered the standard for comparison. The results suggested that the existing vertical-axis criterion was accurate for combinations of gain and natural frequency changes. However, if only the gain or the natural frequency was changed, the rated motion fidelity was better than the criterion predicted. In the vertical axis, the objective and subjective results indicated that a larger gain reduction was tolerated than the existing criterion allowed. The limited data collected in the yaw axis revealed that pilots had difficulty in distinguishing among the variations in the pure yaw motion cues.

GEOGRAPIC INFORMATION SYSTEMS IN DETERMINING ROAD TRAFFIC CRASH ANALYSIS IN IBADAN, NIGERIA.

PubMed

Rukewe, A; Taiwo, O J; Fatiregun, A A; Afuwape, O O; Alonge, T O

2014-01-01

Road traffic accidents are frequent in this environment, hence the need to determine the place of geographic information systems in the documentation of road traffic accidents. To investigate and document the variations in crash frequencies by types and across different road types in Ibadan, Nigeria. Road traffic accident data between January and June 2011 were obtained from the University College Hospital Emergency Department's trauma registry. All the traffic accidents were categorized into motor vehicular, motorbike and pedestrian crashes. Georeferencing of accident locations mentioned by patients was done using a combination of Google Earth and ArcGIS software. Nearest neighbor statistic, Moran's-I, Getis-Ord statistics, Student T-test, and ANOVA were used in investigating the spatial dynamics in crashes. Out of 600 locations recorded, 492 (82.0%) locations were correctly georeferenced. Crashes were clustered in space with motorbike crashes showing greatest clustering. There was significant difference in crashes between dual and non-dual carriage roads (P = 0.0001), but none between the inner city and the periphery (p = 0.115). However, significant variations also exist among the three categories analyzed (p = 0.004) and across the eleven Local Government Areas (P = 0.017). This study showed that the use of Geographic Information System can help in understanding variations in road traffic accident occurrence, while at the same time identifying locations and neighborhoods with unusually higher accidents frequency.

Interannual Variations In the Low-Degree Components of the Geopotential derived from SLR and the Connections With Geophysical/Climatic Processes

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.; Cox, Christopher M.; Au, Andrew Y.

2004-01-01

Recent Satellite Laser Ranging derived long wavelength gravity time series analysis has focused to a large extent on the effects of the recent large changes in the Earth s 52, and the potential causes. However, it is difficult to determine whether there are corresponding signals in the shorter wavelength zonals from the existing SLR-derived time variable gravity results, although it appears that geophysical fluid transport is being observed. For example, the recovered J3 time series shows remarkable agreement with NCEP-derived estimates of atmospheric gravity variations. Likewise, some of the non-zonal spherical harmonic coefficient series have significant interannual signal that appears to be related to mass transport. The non-zonal degree 2 terms show reasonable correlation with atmospheric signals, as well as climatic effects such as El Nino Southern Oscillation. While the formal uncertainty of these terms is significantly higher than that for J2, it is also clear that there is useful signal to be extracted. Consequently, the SLR time series is being reprocessed to improve the time variable gravity field recovery. We will present recent updates on the J2 evolution, as well as a look at other components of the interannual variations of the gravity field, complete through degree 4, and possible geophysical and climatic causes.

Genetic variation in the endangered Southwestern Willow Flycatcher

USGS Publications Warehouse

Busch, Joseph; Miller, Mark P.; Paxton, E.H.; Sogge, M.K.; Keim, Paul

2000-01-01

The Southwestern Willow Flycatcher (Empidonax traillii extimus) is an endangered Neotropical migrant that breeds in isolated remnants of dense riparian habitat in the southwestern United States. We estimated genetic variation at 20 breeding sites of the Southwestern Willow Flycatcher (290 individuals) using 38 amplified fragment length polymorphisms (AFLPs). Our results suggest that considerable genetic diversity exists within the subspecies and within local breeding sites. Statistical analyses of genetic variation revealed only slight, although significant, differentiation among breeding sites (Mantel's r = 0.0705, P < 0.0005; θ = 0.0816, 95% CI = 0.0608 to 0.1034; ΦST = 0.0458, P < 0.001). UPGMA cluster analysis of the AFLP markers indicates that extensive gene flow has occurred among breeding sites. No one site stood out as being genetically unique or isolated. Therefore, the small level of genetic structure that we detected may not be biologically significant. Ongoing field studies are consistent with this conclusion. Of the banded birds that were resighted or recaptured in Arizona during the 1996 to 1998 breeding seasons, one-third moved between breeding sites and two-thirds were philopatric. Low differentiation may be the result of historically high rangewide diversity followed by recent geographic isolation of breeding sites, although observational data indicate that gene flow is a current phenomenon. Our data suggest that breeding groups of E. t. extimus act as a metapopulation.

Spatiotemporal variations of potential evapotranspiration and aridity index in relation to influencing factors over Southwest China during 1960-2013

NASA Astrophysics Data System (ADS)

Zhao, Yifei; Zou, Xinqing; Cao, Liguo; Yao, Yulong; Fu, Guanghe

2017-07-01

This study investigated the spatial-temporal patterns and trends of potential evapotranspiration (ET0) and aridity index (AI) over Southwest China during 1960-2013 based on daily temperature, precipitation, wind speed, sunshine duration, total solar radiation, and relative humidity data from 108 meteorological stations. The Penman-Monteith model, Mann-Kendall (M-K) test, moving t test, and Morlet wavelet method were used. The results indicated that ET0 and AI across the region displayed decreasing trends, but the former was significant. After 2000, regionally average trends in ET0 and AI increased rapidly, indicating that droughts increased over Southwest China in recent years. Spatially, the changes of ET0 and AI were dissimilar and not clustered, either. Temporally, both ET0 and AI displayed obvious abrupt change points over different timescales and that of AI was during the winter monsoon period. Significant periodic variations with periods of 27, 13, and 5 years were found in ET0, but only of 13 and 5 years existed in AI. Correlation analysis revealed that the sunshine duration and wind speed were the dominant factors affecting ET0 and that AI showed strong negative correlation with precipitation. The findings of this study enhance the understanding of the relationship between climate change and drought in Southwest China, while the mechanism controlling the variation in drought requires further study.

Genetic variation of drought tolerance in Pinus pinaster at three hierarchical levels: a comparison of induced osmotic stress and field testing.

PubMed

Gaspar, Maria João; Velasco, Tania; Feito, Isabel; Alía, Ricardo; Majada, Juan

2013-01-01

Understanding the survival capacity of forest trees to periods of severe water stress could improve knowledge of the adaptive potential of different species under future climatic scenarios. In long lived organisms, like forest trees, the combination of induced osmotic stress treatments and field testing can elucidate the role of drought tolerance during the early stages of establishment, the most critical in the life of the species. We performed a Polyethylene glycol-osmotic induced stress experiment and evaluated two common garden experiments (xeric and mesic sites) to test for survival and growth of a wide range clonal collection of Maritime pine. This study demonstrates the importance of additive vs non additive effects for drought tolerance traits in Pinus pinaster, and shows differences in parameters determining the adaptive trajectories of populations and family and clones within populations. The results show that osmotic adjustment plays an important role in population variation, while biomass allocation and hydric content greatly influence survival at population level. Survival in the induced osmotic stress experiment presented significant correlations with survival in the xeric site, and height growth at the mesic site, at population level, indicating constraints of adaptation for those traits, while at the within population level no significant correlation existed. These results demonstrate that population differentiation and within population genetic variation for drought tolerance follow different patterns.

Genetic Variation of Drought Tolerance in Pinus pinaster at Three Hierarchical Levels: A Comparison of Induced Osmotic Stress and Field Testing

PubMed Central

Gaspar, Maria João; Velasco, Tania; Feito, Isabel; Alía, Ricardo; Majada, Juan

2013-01-01

Understanding the survival capacity of forest trees to periods of severe water stress could improve knowledge of the adaptive potential of different species under future climatic scenarios. In long lived organisms, like forest trees, the combination of induced osmotic stress treatments and field testing can elucidate the role of drought tolerance during the early stages of establishment, the most critical in the life of the species. We performed a Polyethylene glycol-osmotic induced stress experiment and evaluated two common garden experiments (xeric and mesic sites) to test for survival and growth of a wide range clonal collection of Maritime pine. This study demonstrates the importance of additive vs non additive effects for drought tolerance traits in Pinus pinaster, and shows differences in parameters determining the adaptive trajectories of populations and family and clones within populations. The results show that osmotic adjustment plays an important role in population variation, while biomass allocation and hydric content greatly influence survival at population level. Survival in the induced osmotic stress experiment presented significant correlations with survival in the xeric site, and height growth at the mesic site, at population level, indicating constraints of adaptation for those traits, while at the within population level no significant correlation existed. These results demonstrate that population differentiation and within population genetic variation for drought tolerance follow different patterns. PMID:24223885

Pheromonally mediated sexual isolation among denning populations of red-sided garter snakes, Thamnophis sirtalis parietalis.

PubMed

Lemaster, Michael P; Mason, Robert T

2003-04-01

Utilizing behavioral experiments and chemical analyses, we examined whether pheromonally mediated sexual isolation exists between denning populations of red-sided garter snakes (Thamtnophis sirtalis parietalis) in Manitoba, Canada. Simultaneous choice tests conducted during the breeding season revealed that adult males from a hibernaculum in central Manitoba displayed a strong courtship preference for females from their own population over females from a hibernaculum in western Manitoba, whereas males from the western Manitoba hibernaculum showed no such preference. In addition. trailing experiments testing the response of males from the two hibernacula to familiar and unfamiliar female trails showed similar results, demonstrating that the observed male preference is mediated through chemical cues. Subsequent chemical analysis of the female sexual attractiveness pheromone. a homologous series of long-chain saturated and (omega-9 cis-unsaturated methyl ketones responsible for eliciting male courtship behavior and trailing behavior in garter snakes, showed significant variation in the composition of the pheromone between the two populations. Specifically, the two populations varied in the relative concentrations of individual unsaturated methyl ketones expressed by females. These results suggest that sexual isolation exists to a degree among denning populations of red-sided garter snakes due to variation in the expression of the female sexual attractiveness pheromone.

The acute mania of King George III: A computational linguistic analysis.

PubMed

Rentoumi, Vassiliki; Peters, Timothy; Conlin, Jonathan; Garrard, Peter

2017-01-01

We used a computational linguistic approach, exploiting machine learning techniques, to examine the letters written by King George III during mentally healthy and apparently mentally ill periods of his life. The aims of the study were: first, to establish the existence of alterations in the King's written language at the onset of his first manic episode; and secondly to identify salient sources of variation contributing to the changes. Effects on language were sought in two control conditions (politically stressful vs. politically tranquil periods and seasonal variation). We found clear differences in the letter corpus, across a range of different features, in association with the onset of mental derangement, which were driven by a combination of linguistic and information theory features that appeared to be specific to the contrast between acute mania and mental stability. The paucity of existing data relevant to changes in written language in the presence of acute mania suggests that lexical, syntactic and stylometric descriptions of written discourse produced by a cohort of patients with a diagnosis of acute mania will be necessary to support the diagnosis independently and to look for other periods of mental illness of the course of the King's life, and in other historically significant figures with similarly large archives of handwritten documents.

Active Travel to School: Findings From the Survey of US Health Behavior in School-Aged Children, 2009-2010.

PubMed

Yang, Yong; Ivey, Stephanie S; Levy, Marian C; Royne, Marla B; Klesges, Lisa M

2016-06-01

Whereas children's active travel to school (ATS) has confirmed benefits, only a few large national surveys of ATS exist. Using data from the Health Behavior in School-aged Children (HBSC) 2009-2010 US survey, we conducted a logistic regression model to estimate the odds ratios of ATS and a linear regression model to estimate the adjusted mean differences of the percentage of ATS within a school. Overall, 21.4% of children engaged in at least one way of active travel to or from school. ATS was less common for trips to school than from school. Greater distance to school was a major barrier preventing children from ATS. Children living in large cities were more likely to engage in ATS, and schools located in a large city had higher proportions of ATS rate. Children having lower family satisfaction, or engaging in a greater number of physically active days during the past week were all more likely to engage in ATS. Although ATS is low among US children, significant variation exists. HBSC is a promising data source for an ATS study. As the first study to explore the variation of ATS at school level, this research contributes uniquely to current knowledge. © 2016, American School Health Association.

Magnetic to magnetic and kinetic to magnetic energy transfers at the top of the Earth's core

NASA Astrophysics Data System (ADS)

Huguet, Ludovic; Amit, Hagay; Alboussière, Thierry

2016-11-01

We develop the theory for the magnetic to magnetic and kinetic to magnetic energy transfer between different spherical harmonic degrees due to the interaction of fluid flow and radial magnetic field at the top of the Earth's core. We show that non-zero secular variation of the total magnetic energy could be significant and may provide evidence for the existence of stretching secular variation, which suggests the existence of radial motions at the top of the Earth's core-whole core convection or MAC waves. However, the uncertainties of the small scales of the geomagnetic field prevent a definite conclusion. Combining core field and flow models we calculate the detailed magnetic to magnetic and kinetic to magnetic energy transfer matrices. The magnetic to magnetic energy transfer shows a complex behaviour with local and non-local transfers. The spectra of magnetic to magnetic energy transfers show clear maxima and minima, suggesting an energy cascade. The kinetic to magnetic energy transfers, which are much weaker due to the weak poloidal flow, are either local or non-local between degree one and higher degrees. The patterns observed in the matrices resemble energy transfer patterns that are typically found in 3-D MHD numerical simulations.

The impact of transposable elements on mammalian development.

PubMed

Garcia-Perez, Jose L; Widmann, Thomas J; Adams, Ian R

2016-11-15

Despite often being classified as selfish or junk DNA, transposable elements (TEs) are a group of abundant genetic sequences that have a significant impact on mammalian development and genome regulation. In recent years, our understanding of how pre-existing TEs affect genome architecture, gene regulatory networks and protein function during mammalian embryogenesis has dramatically expanded. In addition, the mobilization of active TEs in selected cell types has been shown to generate genetic variation during development and in fully differentiated tissues. Importantly, the ongoing domestication and evolution of TEs appears to provide a rich source of regulatory elements, functional modules and genetic variation that fuels the evolution of mammalian developmental processes. Here, we review the functional impact that TEs exert on mammalian developmental processes and discuss how the somatic activity of TEs can influence gene regulatory networks. © 2016. Published by The Company of Biologists Ltd.

Asymmetry in mesial root number and morphology in mandibular second molars: a case report

PubMed Central

Shetty, Shashit; Shekhar, Rhitu

2014-01-01

Ambiguity in the root morphology of the mandibular second molars is quite common. The most common root canal configuration is 2 roots and 3 canals, nonetheless other possibilities may still exist. The presence of accessory roots is an interesting example of anatomic root variation. While the presence of radix entomolaris or radix paramolaris is regarded as a typical clinical finding of a three-rooted mandibular second permanent molar, the occurrence of an additional mesial root is rather uncommon and represents a possibility of deviation from the regular norms. This case report describes successful endodontic management of a three-rooted mandibular second molar presenting with an unusual accessory mesial root, which was identified with the aid of multiangled radiographs and cone-beam computed tomography imaging. This article also discusses the prevalence, etiology, morphological variations, clinical approach to diagnosis, and significance of supernumerary roots in contemporary clinical dentistry. PMID:24516829

Cross-National Moral Beliefs: The Influence of National Religious Context

PubMed Central

Finke, Roger; Adamczyk, Amy

2014-01-01

International surveys have documented wide variation in religious beliefs and practices across nations, but does this variation in the national religious context make a difference? Building on existing theory we explain why religion should have both micro and macro-level effects on morality not sanctioned by the state and why the effects of religion differ from other forms of culture. Using two international surveys and Hierarchical Linear Modeling Techniques (HLM) we sort out the effects of national context and personal beliefs on morality with and without legal underpinnings. We find that national religious context, the respondent’s age, and religious beliefs and practices are the most consistent predictors of the sexual morality index. For morality sanctioned by the state, however, the effects for personal beliefs and practices are attenuated and the effects of the national religious context are no longer significant. PMID:25097270

Revisiting the returns-volume relationship: Time variation, alternative measures and the financial crisis

NASA Astrophysics Data System (ADS)

Cook, Steve; Watson, Duncan

2017-03-01

Following its introduction in the seminal study of Osborne (1959), a voluminous literature has emerged examining the returns-volume relationship for financial assets. The present paper revisits this relationship in an examination of the FTSE100 which extends the existing literature in two ways. First, alternative daily measures of the FTSE100 index are used to create differing returns and absolute returns series to employ in an examination of returns-volume causality. Second, rolling regression analysis is utilised to explore potential time variation in the returns-volume relationship. The findings obtained depict a hitherto unconsidered complexity in this relationship with the type of returns series considered and financial crisis found to be significant underlying factors. The implications of the newly derived results for both the understanding of the nature of the returns-volume relationship and the development of theories in connection to it are discussed.

Toxicogenomics and clinical toxicology: an example of the connection between basic and applied sciences.

PubMed

Ferrer-Dufol, Ana; Menao-Guillen, Sebastian

2009-04-10

The relationship between basic research and its potential clinical applications is often a difficult subject. Clinical toxicology has always been very dependent on experimental research whose usefulness has been impaired by the existence of huge differences in the toxicity expression of different substances, inter- and intra-species which make it difficult to predict clinical effects in humans. The new methods in molecular biology developed in the last decades are furnishing very useful tools to study some of the more relevant molecules implied in toxicokinetic and toxicodynamic processes. We aim to show some meaningful examples of how recent research developments with genes and proteins have clear applications to understand significant clinical matters, such as inter-individual variations in susceptibility to chemicals, and other phenomena related to the way some substances act to induce variations in the expression and functionality of these targets.

Justification bias in self-reported disability: New evidence from panel data.

PubMed

Black, Nicole; Johnston, David W; Suziedelyte, Agne

2017-07-01

The relationship between health and work is frequently investigated using self-assessments of disability from social surveys. The complication is that respondents may overstate their level of disability to justify non-employment and welfare receipt. This study provides new evidence on the existence and magnitude of justification bias by exploiting a novel feature of a large longitudinal survey: each wave respondents are asked identical disability questions twice; near the beginning and end of the face-to-face interview. Prior to answering the second disability question, respondents are asked a series of questions that increase the salience of their employment and welfare circumstances. Justification bias is identified by comparing the variation between the two measures within-individuals over time, with the variation in employment status over time. Results indicate substantial and statistically significant justification bias; especially for men and women who receive disability pensions. Copyright © 2017 Elsevier B.V. All rights reserved.

Context-dependent female mate choice maintains variation in male sexual activity

PubMed Central

Plath, Martin; Gismann, Jakob; Helfrich, Claudia; Bierbach, David

2017-01-01

The existence of individual variation in males' motivation to mate remains a conundrum as directional selection should favour high mating frequencies. Balancing selection resulting from (context-dependent) female mate choice could contribute to the maintenance of this behavioural polymorphism. In dichotomous choice tests, mosquitofish (Gambusia holbrooki) females preferred virtual males showing intermediate mating frequencies, reflecting females' tendencies to avoid harassment by highly sexually active males. When tested in the presence of a female shoal—which protects females from male harassment—focal females showed significantly stronger preferences for high sexual activity. A trade-off between (indirect) benefits and (direct) costs of mating with sexually active males probably explains context-dependent female mate choice, as costs depend on the social environment in which females choose their mates. No preference was observed when we tested virgin females, suggesting that the behavioural pattern described here is part of the learned behavioural repertoire of G. holbrooki females. PMID:28791157

Parameter selection in limited data cone-beam CT reconstruction using edge-preserving total variation algorithms

NASA Astrophysics Data System (ADS)

Lohvithee, Manasavee; Biguri, Ander; Soleimani, Manuchehr

2017-12-01

There are a number of powerful total variation (TV) regularization methods that have great promise in limited data cone-beam CT reconstruction with an enhancement of image quality. These promising TV methods require careful selection of the image reconstruction parameters, for which there are no well-established criteria. This paper presents a comprehensive evaluation of parameter selection in a number of major TV-based reconstruction algorithms. An appropriate way of selecting the values for each individual parameter has been suggested. Finally, a new adaptive-weighted projection-controlled steepest descent (AwPCSD) algorithm is presented, which implements the edge-preserving function for CBCT reconstruction with limited data. The proposed algorithm shows significant robustness compared to three other existing algorithms: ASD-POCS, AwASD-POCS and PCSD. The proposed AwPCSD algorithm is able to preserve the edges of the reconstructed images better with fewer sensitive parameters to tune.

Glassblowers' ocular health and safety: optical radiation hazards and eye protection assessment.

PubMed

Oriowo, O M; Chou, B R; Cullen, A P

1997-05-01

The aims of this study were to investigate the levels of optical radiation exposure in glassblowing and to determine type(s) of protective eyewear commonly used. Radiometric measurements of radiant emissions from different molten glass materials and heating systems were carried out in six installations. Spectral transmittance curves of available protective lenses used at the locations were obtained. Significant variation (P = 0.0001) in ocular irradiation was obtained. All operations produced irradiances higher than the threshold limit values (TLVs) for the visible spectrum (400 to 700 nm). In craft glassblowing which employs furnace systems, irradiance levels exceeding the TLVs for near infrared (760 1o 1100 nm) were obtained. Molten soda-lime and quartz glasses emitted substantial subthreshold near UV radiation. This study shows that variation exists in glassblowing ocular radiation exposure due to different glass materials and heating systems, therefore selection of appropriate eye protector should be on an individual basis.

Market and plan characteristics related to HMO quality and improvement.

PubMed

Scanlon, Dennis P; Swaminathan, Shailender; Chernew, Michael; Lee, Woolton

2006-12-01

Existing research on health plan performance examines whether variation in plans' scores is related to enrollee and health plan traits, primarily using cross-sectional research designs. This study extends that literature by incorporating data on market characteristics using a longitudinal framework. We estimate multivariate growth models that relate plan performance on standard measures to market and HMO characteristics using an unbalanced panel of data for 1998 to 2002. We find that HMO competition is not associated with better performance or greater rates of improvement in performance on the HEDIS chronic care measures. HMO penetration, on the other hand, is positively associated with HEDIS performance in several of the chronic care process-and-outcomes measures but not with a greater rate of improvement through time. Our analysis indicates that a significant percentage of the unexplained variation in quality improvement is because of permanent, unobserved plan-level characteristics that future research should strive to identify.

Modeling Day-to-day Flow Dynamics on Degradable Transport Network

PubMed Central

Gao, Bo; Zhang, Ronghui; Lou, Xiaoming

2016-01-01

Stochastic link capacity degradations are common phenomena in transport network which can cause travel time variations and further can affect travelers’ daily route choice behaviors. This paper formulates a deterministic dynamic model, to capture the day-to-day (DTD) flow evolution process in the presence of degraded link capacity degradations. The aggregated network flow dynamics are driven by travelers’ study of uncertain travel time and their choice of risky routes. This paper applies the exponential-smoothing filter to describe travelers’ study of travel time variations, and meanwhile formulates risk attitude parameter updating equation to reflect travelers’ endogenous risk attitude evolution schema. In addition, this paper conducts theoretical analyses to investigate several significant mathematical characteristics implied in the proposed DTD model, including fixed point existence, uniqueness, stability and irreversibility. Numerical experiments are used to demonstrate the effectiveness of the DTD model and verify some important dynamic system properties. PMID:27959903

Gene differentiation among ten endogamous groups of West Bengal, India.

PubMed

Chakraborty, R; Walter, H; Mukherjee, B N; Malhotra, K C; Sauber, P; Banerjee, S; Roy, M

1986-11-01

Ten endogamous populations of West Bengal, India have been surveyed for genetic variation in 12 systems. These populations encompass all social ranks in the caste hierarchy and cover almost the entire geographic area of the state. Gene diversity analysis suggests that these groups exhibit significant allele frequency variation at all but three loci. The overall genetic difference is not, however, in accord with the classification based on caste. Two low-ranking scheduled caste groups are, in fact, in close proximity with the high-caste ones, suggesting evidence of past generations of gene flow among them. Three different clusters of groups emerge from the present data, providing support for the anthropologic assertion that in Bengal Proto-Australoid, Caucasoid, and Mongoloid racial elements generally coexist. However, these three components are not uniformly present in all groups. Geographic separation of the groups is a strong determinant of the gene differentiation that exists among these populations.

Basal metabolic rate in free-living tropical birds: the influence of phylogenetic, behavioral, and ecological factors

PubMed Central

Tolstenkov, Oleg; Zubkova, Ekaterina; Solovyeva, Eugenia; Kerimov, Anvar

2018-01-01

Abstract The majority of our knowledge of avian energetics is based on studies of birds from temperate and high latitudes. Using the largest existing sample of wild-caught Old World tropical species, we showed that birds from Southern Vietnam had lower basal metabolic rate (BMR) than temperate species. The strongest dissimilarity between tropical and temperate species was the low scaling exponent in the allometric relation between BMR and body mass in tropical birds (the regression slope was 0.573). The passerine migrants to temperate and high latitudes had higher BMR than tropical sedentary passerines. Body mass alone accounted for 93% of the variation in BMR (body mass ranged from 5 to 252 g). Contrary to some other studies, we did not find evidence besides the above mentioned that phylogeny, taxonomy, behavior, or ecology have a significant influence on BMR variation among tropical birds. PMID:29492036

A climate-associated multispecies cryptic cline in the northwest Atlantic

PubMed Central

DiBacco, Claudio; Lowen, Ben; Beiko, Robert G.; Bentzen, Paul; Brickman, David; Johnson, Catherine; Wang, Zeliang; Wringe, Brendan F.; Bradbury, Ian R.

2018-01-01

The spatial genetic structure of most species in the open marine environment remains largely unresolved. This information gap creates uncertainty in the sustainable management, recovery, and associated resilience of marine communities and our capacity to extrapolate beyond the few species for which such information exists. We document a previously unidentified multispecies biogeographic break aligned with a steep climatic gradient and driven by seasonal temperature minima in the northwest Atlantic. The coherence of this genetic break across our five study species with contrasting life histories suggests a pervasive macroecological phenomenon. The integration of this genetic structure with habitat suitability models and climate forecasts predicts significant variation in northward distributional shifts among populations and availability of suitable habitat in future oceans. The results of our integrated approach provide new perspective on how cryptic intraspecific diversity associated with climatic variation influences species and community response to climate change beyond simple poleward shifts. PMID:29600272

American lookback option with fixed strike price—2-D parabolic variational inequality

NASA Astrophysics Data System (ADS)

Chen, Xiaoshan; Yi, Fahuai; Wang, Lihe

In this paper we study a 2-dimensional parabolic variational inequality with financial background. We define a suitable weak formula and obtain existence and uniqueness of the problem. Moreover we analyze the behaviors of the free boundary surface.

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

PubMed Central

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

2010-01-01

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

Intragenomic variation in the ITS rDNA region obscures phylogenetic relationships and inflates estimates of operational taxonomic units in genus Laetiporus

Treesearch

Daniel L. Lindner; Mark T. Banik

2011-01-01

Regions of rDNA are commonly used to infer phylogenetic relationships among fungal species and as DNA barcodes for identification. These regions occur in large tandem arrays, and concerted evolution is believed to reduce intragenomic variation among copies within these arrays, although some variation still might exist. Phylogenetic studies typically use consensus...

Evidence for chemically heterogeneous Arctic mantle beneath the Gakkel Ridge

NASA Astrophysics Data System (ADS)

D'Errico, Megan E.; Warren, Jessica M.; Godard, Marguerite

2016-02-01

Ultraslow spreading at mid-ocean ridges limits melting due to on-axis conductive cooling, leading to the prediction that peridotites from these ridges are relatively fertile. To test this, we examined abyssal peridotites from the Gakkel Ridge, the slowest spreading ridge in the global ocean ridge system. Major and trace element concentrations in pyroxene and olivine minerals are reported for 14 dredged abyssal peridotite samples from the Sparsely Magmatic (SMZ) and Eastern Volcanic (EVZ) Zones. We observe large compositional variations among peridotites from the same dredge and among dredges in close proximity to each other. Modeling of lherzolite trace element compositions indicates varying degrees of non-modal fractional mantle melting, whereas most harzburgite samples require open-system melting involving interaction with a percolating melt. All peridotite chemistry suggests significant melting that would generate a thick crust, which is inconsistent with geophysical observations at Gakkel Ridge. The refractory harzburgites and thin overlying oceanic crust are best explained by low present-day melting of a previously melted heterogeneous mantle. Observed peridotite compositional variations and evidence for melt infiltration demonstrates that fertile mantle components are present and co-existing with infertile mantle components. Melt generated in the Gakkel mantle becomes trapped on short length-scales, which produces selective enrichments in very incompatible rare earth elements. Melt migration and extraction may be significantly controlled by the thick lithosphere induced by cooling at such slow spreading rates. We propose the heterogeneous mantle that exists beneath Gakkel Ridge is the consequence of ancient melting, combined with subsequent melt percolation and entrapment.

Hospital cost control in Norway: a decade's experience with prospective payment.

PubMed Central

Crane, T S

1985-01-01

Under Norway's prospective payment system, which was in existence from 1972 to 1980, hospital costs increased 15.8 percent annually, compared with 15.3 percent in the United States. In 1980 the Norwegian national government started paying for all institutional services according to a population-based, morbidity-adjusted formula. Norway's prospective payment system provides important insights into problems of controlling hospital costs despite significant differences, including ownership of medical facilities and payment and spending as a percent of GNP. Yet striking similarities exist. Annual real growth in health expenditures from 1972 to 1980 in Norway was 2.2 percent, compared with 2.4 percent in the United States. In both countries, public demands for cost control were accompanied by demands for more services. And problems of geographic dispersion of new technology and distribution of resources were similar. Norway's experience in the 1970s demonstrates that prospective payment is no panacea. The annual budget process created disincentives to hospitals to control costs. But Norway's changes in 1980 to a population-based methodology suggest a useful approach to achieve a more equitable distribution of resources. This method of payment provides incentives to control variations in both admissions and cost per case. In contrast, the Medicare approach based on Diagnostic Related Groups (DRGs) is limited, and it does not affect variations in admissions and capital costs. Population-based methodologies can be used in adjusting DRG rates to control both problems. In addition, the DRG system only applies to Medicare payments; the Norwegian experience demonstrates that this system may result in significant shifting of costs onto other payors. PMID:3927385

Epigenetic differentiation and relationship to adaptive genetic divergence in discrete populations of the violet Viola cazorlensis.

PubMed

Herrera, Carlos M; Bazaga, Pilar

2010-08-01

*In plants, epigenetic variations based on DNA methylation are often heritable and could influence the course of evolution. Before this hypothesis can be assessed, fundamental questions about epigenetic variation remain to be addressed in a real-world context, including its magnitude, structuring within and among natural populations, and autonomy in relation to the genetic context. *Extent and patterns of cytosine methylation, and the relationship to adaptive genetic divergence between populations, were investigated for wild populations of the southern Spanish violet Viola cazorlensis (Violaceae) using the methylation-sensitive amplified polymorphism (MSAP) technique, a modification of the amplified fragment length polymorphism method (AFLP) based on the differential sensitivity of isoschizomeric restriction enzymes to site-specific cytosine methylation. *The genome of V. cazorlensis plants exhibited extensive levels of methylation, and methylation-based epigenetic variation was structured into distinct between- and within- population components. Epigenetic differentiation of populations was correlated with adaptive genetic divergence revealed by a Bayesian population-genomic analysis of AFLP data. Significant associations existed at the individual genome level between adaptive AFLP loci and the methylation state of methylation-susceptible MSAP loci. *Population-specific, divergent patterns of correlated selection on epigenetic and genetic individual variation could account for the coordinated epigenetic-genetic adaptive population differentiation revealed by this study.

Laterality strength is linked to stress reactivity in Port Jackson sharks (Heterodontus portusjacksoni).

PubMed

Byrnes, Evan E; Vila Pouca, Catarina; Brown, Culum

2016-05-15

Cerebral lateralization is an evolutionarily deep-rooted trait, ubiquitous among the vertebrates and present even in some invertebrates. Despite the advantages of cerebral lateralization in enhancing cognition and facilitating greater social cohesion, large within population laterality variation exists in many animal species. It is proposed that this variation is maintained due links with inter-individual personality trait differences. Here we explored for lateralization in Port Jackson sharks (Heterodontus portusjacksoni) using T-maze turn and rotational swimming tasks. Additionally, we explored for a link between personality traits, boldness and stress reactivity, and cerebral lateralization. Sharks demonstrated large individual and sex biased laterality variation, with females demonstrating greater lateralization than males overall. Stress reactivity, but not boldness, was found to significantly correlate with lateralization strength. Stronger lateralized individuals were more reactive to stress. Demonstrating laterality in elasmobranchs for the first time indicates ancient evolutionary roots of vertebrate lateralization approximately 240 million years old. Greater lateralization in female elasmobranchs may be related enhancing females' ability to process multiple stimuli during mating, which could increase survivability and facilitate insemination. Despite contrasting evidence in teleost fishes, the results of this study suggest that stress reactivity, and other personality traits, may be linked to variation in lateralization. Copyright © 2016 Elsevier B.V. All rights reserved.

Genetic Mapping of Quantitative Trait Loci Controlling Growth and Wood Quality Traits in Eucalyptus Grandis Using a Maternal Half-Sib Family and Rapd Markers

PubMed Central

Grattapaglia, D.; Bertolucci, FLG.; Penchel, R.; Sederoff, R. R.

1996-01-01

Quantitative trait loci (QTL) mapping of forest productivity traits was performed using an open pollinated half-sib family of Eucalyptus grandis. For volume growth, a sequential QTL mapping approach was applied using bulk segregant analysis (BSA), selective genotyping (SG) and cosegregation analysis (CSA). Despite the low heritability of this trait and the heterogeneous genetic background employed for mapping. BSA detected one putative QTL and SG two out of the three later found by CSA. The three putative QTL for volume growth were found to control 13.7% of the phenotypic variation, corresponding to an estimated 43.7% of the genetic variation. For wood specific gravity five QTL were identified controlling 24.7% of the phenotypic variation corresponding to 49% of the genetic variation. Overlapping QTL for CBH, WSG and percentage dry weight of bark were observed. A significant case of digenic epistasis was found, involving unlinked QTL for volume. Our results demonstrate the applicability of the within half-sib design for QTL mapping in forest trees and indicate the existence of major genes involved in the expression of economically important traits related to forest productivity in Eucalyptus grandis. These findings have important implications for marker-assisted tree breeding. PMID:8913761

Gravity monitoring of Tatun Volcanic Group activities and inference for underground fluid circulations

NASA Astrophysics Data System (ADS)

Mouyen, Maxime; Chao, Benjamin Fong; Hwang, Cheinway; Hsieh, Wen-Chi

2016-12-01

The Tatun Volcano Group (TVG), located on the northern coast of Taiwan adjacent to the city of Taipei, experiences active hydrothermalism but has no historical record of volcanic eruption. Yet recent studies suggest that TVG is dormant-active rather than extinct. To monitor mass transfers and to gain further understanding of this volcanic area, gravity variations have been recorded continuously since 2012 using a superconducting gravimeter, and once every few months since 2005 using absolute gravimeters. We analyze the continuous gravity time series and propose a model that best explains the gravity variations due to local groundwater redistribution. By correcting these variations, we identify gravity changes as large as 35 μGal that occurred concomitantly to fluid pressure-induced earthquakes and changes in the gas composition at Dayoukeng, one of TVG's fumaroles, over 2005-2007. We examine several fluid movements that can match the gravity observations, yet too few additional constraints exist to favor any of them. In particular, no significant ground displacements are observed when these gravity variations occurred. On the other hand, the model of gravity changes due to local groundwater redistribution can be routinely computed and removed from the ongoing time gravity measurements in order to quickly identify any unusual mass transfer occurring beneath TVG.

Gravity monitoring of Tatun Volcanic Group activities and inference for underground fluid circulations

NASA Astrophysics Data System (ADS)

Mouyen, Maxime; Chao, Benjamin; Hwang, Cheinway; Hsieh, Wen-Chi

2017-04-01

The Tatun Volcano Group (TVG), located on the northern coast of Taiwan adjacent to the city of Taipei, experiences active hydrothermalism but has no historical record of volcanic eruption. Yet recent studies suggest that TVG is dormant-active rather than extinct. To monitor mass transfers and to gain further understanding of this volcanic area, gravity variations have been recorded continuously since 2012 using a superconducting gravimeter, and once every few months since 2005 using absolute gravimeters. We analyze the continuous gravity time series and propose a model that best explain the gravity variations due to local groundwater redistribution. By correcting these variations, we identify gravity changes as large as 35 µGal that occurred concomitantly to fluid pressure-induced earthquakes and changes in the gas composition at Dayoukeng, one of TVG's fumaroles, over 2005-2007. We examine several fluid movements that can match the gravity observations, yet too few additional constraints exist to favor any of them. In particular, no significant ground displacements are observed when these gravity variations occurred. On the other hand, the model of gravity changes due to local groundwater redistribution can be routinely computed and removed from the ongoing time gravity measurements in order to quickly identify any unusual mass transfer occurring beneath TVG.

Intraspecific variation in juvenile tree growth under elevated CO2 alone and with O3: a meta-analysis.

PubMed

Resco de Dios, Víctor; Mereed, Tessema E; Ferrio, Juan Pedro; Tissue, David T; Voltas, Jordi

2016-06-01

Atmospheric carbon dioxide (CO2) concentrations are expected to increase throughout this century, potentially fostering tree growth. A wealth of studies have examined the variation in CO2 responses across tree species, but the extent of intraspecific variation in response to elevated CO2 (eCO2) has, so far, been examined in individual studies and syntheses of published work are currently lacking. We conducted a meta-analysis on the effects of eCO2 on tree growth (height, stem biomass and stem volume) and photosynthesis across genotypes to examine whether there is genetic variation in growth responses to eCO2 and to understand their dependence on photosynthesis. We additionally examined the interaction between the responses to eCO2 and ozone (O3), another global change agent. Most of the published studies so far have been conducted in juveniles and in Populus spp., although the patterns observed were not species dependent. All but one study reported significant genetic variation in stem biomass, and the magnitude of intraspecific variation in response to eCO2 was similar in magnitude to previous analyses on interspecific variation. Growth at eCO2 was predictable from growth at ambient CO2 (R(2) = 0.60), and relative rankings of genotype performance were preserved across CO2 levels, indicating no significant interaction between genotypic and environmental effects. The growth response to eCO2 was not correlated with the response of photosynthesis (P > 0.1), and while we observed 57.7% average increases in leaf photosynthesis, stem biomass and volume increased by 36 and 38.5%, respectively, and height only increased by 9.5%, suggesting a predominant role for carbon allocation in ultimately driving the response to eCO2 Finally, best-performing genotypes under eCO2 also responded better under eCO2 and elevated O3 Further research needs include widening the study of intraspecific variation beyond the genus Populus and examining the interaction between eCO2 and other environmental stressors. We conclude that significant potential to foster CO2-induced productivity gains through tree breeding exists, that these programs could be based upon best-performing genotypes under ambient conditions and that they would benefit from an increased understanding on the controls of allocation. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Identification of natural high-oleate mutants from the USDA Peanut Germplasm Collection

USDA-ARS?s Scientific Manuscript database

Natural genetic variation may exist in plant germplasm collections. Identifying genetic variation may provide useful materials for breeders to develop new cultivars. After screening 8,846 cultivated peanut germplasm accessions by gas chromatography analysis, we identified three natural mutant lines ...

Geographic variation in health insurance benefits in Qianjiang District, China: a cross-sectional study.

PubMed

Wu, Yue; Zhang, Liang; Liu, Xuejiao; Ye, Ting; Wang, Yongfei

2018-02-05

Health insurance contributes to reducing the economic burden of disease and improving access to healthcare. In 2016, the Chinese government announced the integration of the New Cooperative Medical Scheme (NCMS) and Urban Resident Basic Medical Insurance (URBMI) to reduce system segmentation. Nevertheless, it was unclear whether there would be any geographic variation in health insurance benefits if the two types of insurance were integrated. The aim of this study was to identify the potential geographic variation in health insurance benefits and the related contributing factors. This cross-sectional study was carried out in Qianjiang District, where the NCMS and URBMI were integrated into Urban and Rural Resident Basic Medical Insurance Scheme (URRBMI) in 2010. All beneficiaries under the URRBMI were hospitalized at least once in 2013, totaling 445,254 persons and 65,877 person-times, were included in this study. Town-level data on health insurance benefits, healthcare utilization, and socioeconomic and geographical characteristics were collected through health insurance system, self-report questionnaires, and the 2014 Statistical Yearbook of Qianjiang District. A simplified Theil index at town level was calculated to measure geographic variation in health insurance benefits. Colored maps were created to visualize the variation in geographic distribution of benefits. The effects of healthcare utilization and socioeconomic and geographical characteristics on geographic variation in health insurance benefits were estimated with a multiple linear regression analysis. Different Theil index values were calculated for different towns, and the Theil index values for compensation by person-times and amount were 2.5028 and 1.8394 in primary healthcare institutions and 1.1466 and 0.9204 in secondary healthcare institutions. Healthcare-seeking behavior and economic factors were positively associated with health insurance benefits in compensation by person-times significantly, meanwhile, geographical accessibility and economic factors had positive effects (p < 0.05). The geographic variation in health insurance benefits widely existed in Qianjiang District and the distribution of health insurance benefits for insured inpatients in primary healthcare institutions was distinctly different from that in secondary healthcare institutions. When combining the NRCM and URMIS in China, the geographical accessibility, healthcare-seeking behavior and economic factors required significant attention.

Inherited variation in immune response genes in follicular lymphoma and diffuse large B-cell lymphoma.

PubMed

Nielsen, Kaspar Rene; Steffensen, Rudi; Haunstrup, Thure Mors; Bødker, Julie Støve; Dybkær, Karen; Baech, John; Bøgsted, Martin; Johnsen, Hans Erik

2015-01-01

Diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) both depend on immune-mediated survival and proliferation signals from the tumor microenvironment. Inherited genetic variation influences this complex interaction. A total of 89 studies investigating immune-response genes in DLBCL and FL were critically reviewed. Relatively consistent association exists for variation in the tumor necrosis factor alpha (TNFA) and interleukin-10 loci and DLBCL risk; for DLBCL outcome association with the TNFA locus exists. Variations at chromosome 6p31-32 were associated with FL risk. Importantly, individual risk alleles have been shown to interact with each other. We suggest that the pathogenetic impact of polymorphic genes should include gene-gene interaction analysis and should be validated in preclinical model systems of normal B lymphopoiesis and B-cell malignancies. In the future, large cohort studies of interactions and genome-wide association studies are needed to extend the present findings and explore new risk alleles to be studied in preclinical models.

Cross-cultural variations in the prevalence and presentation of anxiety disorders.

PubMed

Marques, Luana; Robinaugh, Donald J; LeBlanc, Nicole J; Hinton, Devon

2011-02-01

Considerable cross-cultural variation exists in the prevalence and presentation of the anxiety disorders as defined by the fourth edition of the Diagnostic and Statistical Manual. Researchers debate whether this variation represents cultural differences in the phenomenology of universal disorders or the existence of unique culturally constructed disorders. This article reviews recent literature on the prevalence and presentation of five anxiety disorders: generalized anxiety disorder, social anxiety disorder, panic disorder, specific phobia and post-traumatic stress disorder, both across countries and within the USA. This article indicates that certain anxiety disorders (e.g., generalized anxiety disorder and panic disorder) may vary greatly in rate across cultural groups. It indicates that the clinical presentation of anxiety disorders, with respect to symptom presentation and the interpretation of symptoms, varies across cultures. A difference in catastrophic cognitions about anxiety symptoms across cultures is hypothesized to be a key aspect of cross-cultural variation in the anxiety disorders. Future research directions are suggested.

Geographic variation in the relationship between body mass index and the built environment.

PubMed

Adachi-Mejia, Anna M; Lee, Chanam; Lee, Chunkuen; Carlos, Heather A; Saelens, Brian E; Berke, Ethan M; Doescher, Mark P

2017-07-01

Studies examining associations between weight status and neighborhood built environment (BE) have shown inconsistent results and have generally focused on urban settings. However, many Americans do not live in metropolitan areas and BE impacts may be different outside of metropolitan areas. We sought to examine whether the relationship between body mass index (BMI) and neighborhood BE exists and varies by geographic region across small towns in the United States. We conducted telephone surveys with 2156 adults and geographic information systems data in nine towns located within three geographic regions (Northeast, Texas, Washington) in 2011 and 2012. Multiple regression models examined the relationship between individual BMI and BE measures. Most physical activity variables were significantly associated with lower BMI in all geographic regions. We saw variation across geographic region in the relationship between characteristics of the BE variables and BMI. Some perceived and objectively-measured characteristics of the BE were significantly associated with adult BMI, but significant relationships varied by geographic region. For example, in the Northeast, perceived attractiveness of the neighborhood as a reason for why they chose to live there was associated with lower BMI; in Texas, the perceived presence of a fast food restaurant was negatively associated with BMI; in Washington, perceived presence of trees along the streets was associated with lower BMI. Our findings suggest that regional variation plays a role in the relationship between adult BMI and BE characteristics in small towns. Regardless of geographic location, interventions should encourage utilitarian walking and other forms of physical activity. Copyright © 2017 Elsevier Inc. All rights reserved.

Piracetam in the treatment of cortical myoclonus.

PubMed

Genton, P; Guerrini, R; Remy, C

1999-03-01

This paper reviews existing publications on the use of piracetam for the treatment of cortical myoclonus of various etiologies and includes the personal experience of the authors in progressive myoclonus epilepsy. Two double-blind comparisons with placebo provided results which allow recommendations for the dosage and usage of piracetam in cortical myoclonus. Wide individual variation (7-24g daily) exists in dosage requirements but responses are dose-related so that dosage should be increased until an optimum effect is obtained. Tolerability after long-term use of piracetam in high dosage has been very good and without toxicity or serious adverse effects. Side effects have been occasional, mild and transient. The authors present their experience of 12 patients with progressive myoclonus epilepsy in whom the administration of up to 45 g piracetam daily, when added to existing anti-epileptic treatment, caused marked and sometimes spectacular improvement and was without significant adverse effects. Improvement was maintained for up to 7 years. The use of piracetam for disabling cortical myoclonus of any etiology, either as an addition to existing antimyoclonic drugs or as monotherapy, may bring about profound improvement in disability and quality of life. Piracetam should be considered a first-line drug for the treatment of cortical myoclonus.

Genetic influences in sport and physical performance.

PubMed

Puthucheary, Zudin; Skipworth, James R A; Rawal, Jai; Loosemore, Mike; Van Someren, Ken; Montgomery, Hugh E

2011-10-01

The common inheritance of approximately 20 000 genes defines each of us as human. However, substantial variation exists between individual human genomes, including 'replication' of gene sequences (copy number variation, tandem repeats), or changes in individual base pairs (mutations if <1% frequency and single nucleotide polymorphisms if >1% frequency). A vast array of human phenotypes (e.g. muscle strength, skeletal structure, tendon elasticity, and heart and lung size) influences sports performance, each itself the result of a complex interaction between a myriad of anatomical, biochemical and physiological systems. This article discusses the role for genetic influences in influencing sporting performance and injury, offering specific exemplars where these are known. Many of these preferable genotypes are uncommon, and their combination even rarer. In theory, the chances of an individual having a perfect sporting genotype are much lower than 1 in 20 million - as the number of associated polymorphisms increase, the odds decrease correspondingly. Many recently discovered polymorphisms that may affect sports performance have been described in animal or other human based models, and have been included in this review if they may apply to athletic populations. Muscle performance is heavily influenced by basal muscle mass and its dynamic response to training. Genetic factors account for approximately 50-80% of inter-individual variation in lean body mass, with impacts detected on both 'training-naive' muscle mass and its growth response. Several cytokines such as interleukin-6 and -15, cilliary neurotrophic factor and insulin-like growth factor (IGF) have myoanabolic effects. Genotype-associated differences in endocrine function, necessary for normal skeletal muscle growth and function, may also be of significance, with complex interactions existing between thyroxine, growth hormone and the downstream regulators of the anabolic pathways (such as IGF-1 and IGF-2). Almost 200 polymorphisms are known to exist in the vitamin D receptor (VDR) gene. VDR genotype is associated with differences in strength in premenopausal women. VDR expression decreases with age and VDR genotype is associated with fat-free mass and strength in elderly men and women. Muscle fibre type determination is complex. Whilst initial composition is likely to be strongly influenced by genetic factors, training has significant effects on fibre shifts. Polymorphisms of the peroxisome proliferator-activated receptor α (PPARα) gene and R577x polymorphism of the ACTN3 gene are both associated with specific fibre compositions. Alterations in cardiac size have been associated with both increased performance and excess cardiovascular mortality. PPARα is a ligand-activated transcription factor that regulates genes involved in fatty acid uptake and oxidation, lipid metabolism and inflammation. Psychology plays an important role in training, competition, tolerance of pain and motivation. However, the role of genetic variation in determining psychological state and responses remains poorly understood; only recently have specific genes been implicated in motivational behaviour and maintenance of exercise. Thyroid hormone receptors exist within the brain and influence both neurogenesis and behaviour. With the current state of knowledge, the field of genetic influences on sports performance remains in its infancy, despite over a decade of research.

Impact of downward-mixing ozone on surface ozone accumulation in southern Taiwan.

PubMed

Lin, Ching-Ho

2008-04-01

The ozone that initially presents in the previous day's afternoon mixing layer can remain in the nighttime atmosphere and then be carried over to the next morning. Finally, this ozone can be brought to the ground by downward mixing as mixing depth increases during the daytime, thereby increasing surface ozone concentrations. Variation of ozone concentration during each of these periods is investigated in this work. First, ozone concentrations existing in the daily early morning atmosphere at the altitude range of the daily maximum mixing depth (residual ozone concentrations) were measured using tethered ozonesondes on 52 experimental days during 2004-2005 in southern Taiwan. Daily downward-mixing ozone concentrations were calculated by a box model coupling the measured daily residual ozone concentrations and daily mixing depth variations. The ozone concentrations upwind in the previous day's afternoon mixing layer were estimated by the combination of back air trajectory analysis and known previous day's surface ozone distributions. Additionally, the relationship between daily downward-mixing ozone concentration and daily photochemically produced ozone concentration was examined. The latter was calculated by removing the former from daily surface maximum ozone concentration. The measured daily residual ozone concentrations distributed at 12-74 parts per billion (ppb) with an average of 42 +/- 17 ppb are well correlated with the previous upwind ozone concentration (R2 = 0.54-0.65). Approximately 60% of the previous upwind ozone was estimated to be carried over to the next morning and became the observed residual ozone. The daily downward-mixing ozone contributes 48 +/- 18% of the daily surface maximum ozone concentration, indicating that the downward-mixing ozone is as important as daily photochemically produced ozone to daily surface maximum ozone accumulation. The daily downward-mixing ozone is poorly correlated with the daily photochemically produced ozone and contributes significantly to the daily variation of surface maximum ozone concentrations (R2 = 0.19). However, the contribution of downward-mixing ozone to daily ozone variation is not included in most existing statistical models developed for predicting daily ozone variation. Finally, daily surface maximum ozone concentration is positively correlated with daily afternoon mixing depth, attributable to the downward-mixing ozone.

Ribosomal DNA sequence heterogeneity reflects intraspecies phylogenies and predicts genome structure in two contrasting yeast species.

PubMed

West, Claire; James, Stephen A; Davey, Robert P; Dicks, Jo; Roberts, Ian N

2014-07-01

The ribosomal RNA encapsulates a wealth of evolutionary information, including genetic variation that can be used to discriminate between organisms at a wide range of taxonomic levels. For example, the prokaryotic 16S rDNA sequence is very widely used both in phylogenetic studies and as a marker in metagenomic surveys and the internal transcribed spacer region, frequently used in plant phylogenetics, is now recognized as a fungal DNA barcode. However, this widespread use does not escape criticism, principally due to issues such as difficulties in classification of paralogous versus orthologous rDNA units and intragenomic variation, both of which may be significant barriers to accurate phylogenetic inference. We recently analyzed data sets from the Saccharomyces Genome Resequencing Project, characterizing rDNA sequence variation within multiple strains of the baker's yeast Saccharomyces cerevisiae and its nearest wild relative Saccharomyces paradoxus in unprecedented detail. Notably, both species possess single locus rDNA systems. Here, we use these new variation datasets to assess whether a more detailed characterization of the rDNA locus can alleviate the second of these phylogenetic issues, sequence heterogeneity, while controlling for the first. We demonstrate that a strong phylogenetic signal exists within both datasets and illustrate how they can be used, with existing methodology, to estimate intraspecies phylogenies of yeast strains consistent with those derived from whole-genome approaches. We also describe the use of partial Single Nucleotide Polymorphisms, a type of sequence variation found only in repetitive genomic regions, in identifying key evolutionary features such as genome hybridization events and show their consistency with whole-genome Structure analyses. We conclude that our approach can transform rDNA sequence heterogeneity from a problem to a useful source of evolutionary information, enabling the estimation of highly accurate phylogenies of closely related organisms, and discuss how it could be extended to future studies of multilocus rDNA systems. [concerted evolution; genome hydridisation; phylogenetic analysis; ribosomal DNA; whole genome sequencing; yeast]. © The Author(s) 2014. Published by Oxford University Press, on behalf of the Society of Systematic Biologists.

Actinide abundances in ordinary chondrites

USGS Publications Warehouse

Hagee, B.; Bernatowicz, T.J.; Podosek, F.A.; Johnson, M.L.; Burnett, D.S.; Tatsumoto, M.

1990-01-01

Measurements of 244Pu fission Xe, U, Th, and light REE (LREE) abundances, along with modal petrographic determinations of phosphate abundances, were carried out on equilibrated ordinary chondrites in order to define better the solar system Pu abundance and to determine the degree of variation of actinide and LREE abundances. Our data permit comparison of the directly measured Pu/ U ratio with that determined indirectly as (Pu/Nd) ?? (Nd/U) assuming that Pu behaves chemically as a LREE. Except for Guaren??a, and perhaps H chondrites in general, Pu concentrations are similar to that determined previously for St. Se??verin, although less precise because of higher trapped Xe contents. Trapped 130Xe 136Xe ratios appear to vary from meteorite to meteorite, but, relative to AVCC, all are similar in the sense of having less of the interstellar heavy Xe found in carbonaceous chondrite acid residues. The Pu/U and Pu/Nd ratios are consistent with previous data for St. Se??verin, but both tend to be slightly higher than those inferred from previous data on Angra dos Reis. Although significant variations exist, the distribution of our Th/U ratios, along with other precise isotope dilution data for ordinary chondrites, is rather symmetric about the CI chondrite value; however, actinide/(LREE) ratios are systematically lower than the CI value. Variations in actinide or LREE absolute and relative abundances are interpreted as reflecting differences in the proportions and/or compositions of more primitive components (chondrules and CAI materials?) incorporated into different regions of the ordinary chondrite parent bodies. The observed variations of Th/U, Nd/U, or Ce/U suggest that measurements of Pu/U on any single equilibrated ordinary chondrite specimen, such as St. Se??verin, should statistically be within ??20-30% of the average solar system value, although it is also clear that anomalous samples exist. ?? 1990.

A New Phylogeographic Pattern of Endemic Bufo bankorensis in Taiwan Island Is Attributed to the Genetic Variation of Populations

PubMed Central

Yu, Teng-Lang; Lin, Hung-Du; Weng, Ching-Feng

2014-01-01

Aim To comprehend the phylogeographic patterns of genetic variation in anurans at Taiwan Island, this study attempted to examine (1) the existence of various geological barriers (Central Mountain Ranges, CMRs); and (2) the genetic variation of Bufo bankorensis using mtDNA sequences among populations located in different regions of Taiwan, characterized by different climates and existing under extreme conditions when compared available sequences of related species B. gargarizans of mainland China. Methodology/Principal Findings Phylogenetic analyses of the dataset with mitochondrial DNA (mtDNA) D-loop gene (348 bp) recovered a close relationship between B. bankorensis and B. gargarizans, identified three distinct lineages. Furthermore, the network of mtDNA D-loop gene (564 bp) amplified (279 individuals, 27 localities) from Taiwan Island indicated three divergent clades within B. bankorensis (Clade W, E and S), corresponding to the geography, thereby verifying the importance of the CMRs and Kaoping River drainage as major biogeographic barriers. Mismatch distribution analysis, neutrality tests and Bayesian skyline plots revealed that a significant population expansion occurred for the total population and Clade W, with horizons dated to approximately 0.08 and 0.07 Mya, respectively. These results suggest that the population expansion of Taiwan Island species B. bankorensis might have resulted from the release of available habitat in post-glacial periods, the genetic variation on mtDNA showing habitat selection, subsequent population dispersal, and co-distribution among clades. Conclusions The multiple origins (different clades) of B. bankorensis mtDNA sequences were first evident in this study. The divergent genetic clades found within B. bankorensis could be independent colonization by previously diverged lineages; inferring B. bankorensis originated from B. gargarizans of mainland China, then dispersal followed by isolation within Taiwan Island. Highly divergent clades between W and E of B. bankorensis, implies that the CMRs serve as a genetic barrier and separated the whole island into the western and eastern phylogroups. PMID:24853679

Spatial variation of slip behavior beneath the Alaska Peninsula along Alaska-Aleutian Subduction Zone

NASA Astrophysics Data System (ADS)

Li, S.; Freymueller, J. T.

2017-12-01

The Alaska Peninsula, including the Shumagin and Semidi segments in the Alaska-Aleutian subduction zone, is one of the best places in the world to study along-strike variations in the seismogenic zone. Understanding the cause of along-strike variations on the plate interface and seismic potential is significant for better understanding of the dynamic mechanical properties of faults and the rheology of the lower crust and lithospheric mantle in subduction zones. GPS measurements can be used to study these properties and estimate the slip deficit distribution on the plate interface. We re-surveyed pre-existing (1992-2001) campaign GPS sites in 2016 and estimated a new dense and highly precise GPS velocity field for the Alaska Peninsula. We find evidence for only minimal time variations in the slip distribution in the region. We used the TDEFNODE software package to invert for the slip deficit distribution from the new velocities. There are long-wavelength systematic misfits to the vertical velocities from the optimal model that fits the horizontal velocities well, which cannot be explained by altering the slip distribution on the subduction plate interface. Possible explanations for the systematic misfit are still under investigation since the plate geometry, GIA effect and reference frame errors do not explain the misfits. In this study, we use only the horizontal velocities. We divided the overall Alaska Peninsula area into three sub-areas, which have strong differences in the pattern of the observed deformation, and explored optimal models for each sub-area. The width of the locked region decreases step-wise from NE to SW along strike. Then we compared each of these models to all of the data to identify the locations of the along-strike boundaries that mark the transition from strongly to weakly coupled segments of the margin. We identified three sharp boundaries separating segments with different fault slip deficit rate distributions. Significant change in fault coupling from strong to weak are spatially correlated with the change in pre-existing plate fabric caused by cessation of the Kula-Pacific spreading and reorientation of the northern section of Farallon-Pacific spreading, which also correlate with changes in the degree of outer rise normal faulting and hydration of the downgoing plate.

Sex hormones in Malay and Chinese men in Malaysia: are there age and race differences?

PubMed Central

Chin, Kok-Yong; Soelaiman, Ima-Nirwana; Mohamed, Isa Naina; Ahmad, Fairus; Ramli, Elvy Suhana Mohd; Aminuddin, Amilia; Ngah, Wan Zurinah Wan

2013-01-01

OBJECTIVES: Variations in the prevalence of sex-hormone-related diseases have been observed between Asian ethnic groups living in the same country; however, available data concerning their sex hormone levels are limited. The present study aimed to determine the influence of ethnicity and age on the sex hormone levels of Malay and Chinese men in Malaysia. METHODS: A total of 547 males of Malay and Chinese ethnicity residing in the Klang Valley Malaysia underwent a detailed screening, and their blood was collected for sex hormones analyses. RESULTS: Testosterone levels were normally distributed in the men (total, free and non-sex hormone-binding globulin (SHBG) bound fractions), and significant ethnic differences were observed (p<0.05); however, the effect size was small. In general, testosterone levels in males began to decline significantly after age 50. Significant ethnic differences in total, free and non-SHBG bound fraction estradiol levels were observed in the 20-29 and 50-59 age groups (p<0.05). The estradiol levels of Malay men decreased as they aged, but they increased for Chinese men starting at age 40. CONCLUSIONS: Small but significant differences in testosterone levels existed between Malay and Chinese males. Significant age and race differences existed in estradiol levels. These differences might contribute to the ethnic group differences in diseases related to sex hormones, which other studies have found in Malaysia. PMID:23525310

Sex hormones in Malay and Chinese men in Malaysia: are there age and race differences?

PubMed

Chin, Kok-Yong; Soelaiman, Ima-Nirwana; Mohamed, Isa Naina; Ahmad, Fairus; Ramli, Elvy Suhana Mohd; Aminuddin, Amilia; Ngah, Wan Zurinah Wan

2013-01-01

Variations in the prevalence of sex-hormone-related diseases have been observed between Asian ethnic groups living in the same country; however, available data concerning their sex hormone levels are limited. The present study aimed to determine the influence of ethnicity and age on the sex hormone levels of Malay and Chinese men in Malaysia. A total of 547 males of Malay and Chinese ethnicity residing in the Klang Valley Malaysia underwent a detailed screening, and their blood was collected for sex hormones analyses. Testosterone levels were normally distributed in the men (total, free and non-sex hormone-binding globulin (SHBG) bound fractions), and significant ethnic differences were observed (p<0.05); however, the effect size was small. In general, testosterone levels in males began to decline significantly after age 50. Significant ethnic differences in total, free and non-SHBG bound fraction estradiol levels were observed in the 20-29 and 50-59 age groups (p<0.05). The estradiol levels of Malay men decreased as they aged, but they increased for Chinese men starting at age 40. Small but significant differences in testosterone levels existed between Malay and Chinese males. Significant age and race differences existed in estradiol levels. These differences might contribute to the ethnic group differences in diseases related to sex hormones, which other studies have found in Malaysia.

Microvariability in Seyfert galaxies

USGS Publications Warehouse

Carini, M.T.; Noble, J.C.; Miller, H.R.

2003-01-01

We present the results of a search for microvariability in a sample of eight Seyfert galaxies. Microvariability (i.e., variations occurring on timescales of tens of minutes to hours) has been conclusively demonstrated to exist in the class of active galactic nuclei (AGNs) known as blazars. Its existence in other classes of AGNs is far less certain. We present the results of a study of eight Seyfert 1 galaxies, which were intensively monitored in order to determine whether such variations exist in these objects. Only one object, Ark 120, displayed any evidence of microvariations. The implications of these results with respect to current models of the mechanisms responsible for the observed emission in Seyfert galaxies are discussed. We compare our results with those obtained from other studies of microvariability in different classes of AGNs.

Ethnic variation in cancer patients’ ratings of information provision, communication and overall care

PubMed Central

Trenchard, Lorna; Mc Grath-Lone, Louise; Ward, Helen

2016-01-01

ABSTRACT Objective. Ethnic inequalities in cancer patient experience exist but variation within broad ethnic categories is under-explored. This study aimed to describe variation by ethnic sub-category in experiences of information provision and communication (key domains of patient experience) using National Cancer Patient Experience Survey (NCPES) data. Design. The NCPES 2012–2013 contained responses from 68,737 cancer patients treated at 155 NHS Trusts in England. Multivariate logistic regression was used to investigate associations between ethnicity and patients’ ratings of overall care, information provision and communication. Results. Variation by and within broad ethnic categories was evident. Non-White patients (particularly Asian patients (ORadj:0.78; 95%CI:0.67-0.90, p=0.001)) were less likely than White patients to receive an understandable explanation of treatment side effects. Among Asian patients, those of Bangladeshi ethnicity were least likely to receive an understandable explanation. Conclusions. Effective communication and information provision are important to ensure patients are well informed, receive the best possible care and have a positive patient experience. However, ethnic inequalities exist in cancer patients’ experiences of information provision and communication with variation evident both between and within broad ethnic categories. Further work to understand the causes of this variation is required to address ethnic inequalities at practice and policy level. PMID:26853061

Ethnic variation in cancer patients' ratings of information provision, communication and overall care.

PubMed

Trenchard, Lorna; Mc Grath-Lone, Louise; Ward, Helen

2016-10-01

Ethnic inequalities in cancer patient experience exist but variation within broad ethnic categories is under-explored. This study aimed to describe variation by ethnic sub-category in experiences of information provision and communication (key domains of patient experience) using National Cancer Patient Experience Survey (NCPES) data. The NCPES 2012-2013 contained responses from 68,737 cancer patients treated at 155 NHS Trusts in England. Multivariate logistic regression was used to investigate associations between ethnicity and patients' ratings of overall care, information provision and communication. Variation by and within broad ethnic categories was evident. Non-White patients (particularly Asian patients (ORadj:0.78; 95%CI:0.67-0.90, p=0.001)) were less likely than White patients to receive an understandable explanation of treatment side effects. Among Asian patients, those of Bangladeshi ethnicity were least likely to receive an understandable explanation. Effective communication and information provision are important to ensure patients are well informed, receive the best possible care and have a positive patient experience. However, ethnic inequalities exist in cancer patients' experiences of information provision and communication with variation evident both between and within broad ethnic categories. Further work to understand the causes of this variation is required to address ethnic inequalities at practice and policy level.

Effect of acculturation on variations in having a usual source of care among Asian Americans and non-Hispanic whites in California.

PubMed

Chang, Eva; Chan, Kitty S; Han, Hae-Ra

2015-02-01

We examined variations in having a usual source of care (USC) among non-Hispanic White and Asian American adults in California. Data were from the 2005 and 2009 California Health Interview Survey. Using a modified Anderson model, we used multiple logistic regression to compare odds of having a USC between non-Hispanic White (n=38554) and Asian American adults (n=7566) and to examine associations with acculturation factors (English proficiency, length of residence, residence in a racially concordant neighborhood) and key enabling (employment, income, insurance) and predisposing (education) factors. Race-related disparities between Asian Americans and non-Hispanic Whites in having a USC were no longer significant after accounting for acculturation factors. Limited English proficiency and short time in the United States (<5 years) were significantly associated with not having a USC for both races. Increasing levels of education and insurance were not associated with better access among Asian Americans. Key differences exist in how Asian American and non-Hispanic White adults access care. Acculturation factors are key drivers of disparities and should be included in access-to-care models with Asians. Insurance and education are differentially significant for Asian Americans and non-Hispanic Whites.

Effect of Acculturation on Variations in Having a Usual Source of Care Among Asian Americans and Non-Hispanic Whites in California

PubMed Central

Han, Hae-Ra

2015-01-01

Objectives. We examined variations in having a usual source of care (USC) among non-Hispanic White and Asian American adults in California. Methods. Data were from the 2005 and 2009 California Health Interview Survey. Using a modified Anderson model, we used multiple logistic regression to compare odds of having a USC between non-Hispanic White (n = 38 554) and Asian American adults (n = 7566) and to examine associations with acculturation factors (English proficiency, length of residence, residence in a racially concordant neighborhood) and key enabling (employment, income, insurance) and predisposing (education) factors. Results. Race-related disparities between Asian Americans and non-Hispanic Whites in having a USC were no longer significant after accounting for acculturation factors. Limited English proficiency and short time in the United States (< 5 years) were significantly associated with not having a USC for both races. Increasing levels of education and insurance were not associated with better access among Asian Americans. Conclusions. Key differences exist in how Asian American and non-Hispanic White adults access care. Acculturation factors are key drivers of disparities and should be included in access-to-care models with Asians. Insurance and education are differentially significant for Asian Americans and non-Hispanic Whites. PMID:25033147

Au 329–xAg x(SR) 84 Nanomolecules: Plasmonic Alloy Faradaurate-329

DOE PAGES

Kumara, Chanaka; Zuo, Xiaobing; Cullen, David A.; ...

2015-08-10

Though significant progress has been made to improve the monodispersity of larger (>10 nm) alloy metal nanoparticles, there still exists a significant variation in nanoparticle composition, ranging from ±1000s of atoms. Here in this paper, for the first time, we report the synthesis of atomically precise (±0 metal atom variation) Au 329–xAg x(SCH 2CH 2Ph) 84 alloy nanomolecules. The composition was determined using high resolution electrospray ionization mass spectrometry. In contrast to larger (>10 nm) Au–Ag nanoparticles, the surface plasmon resonance (SPR) peak does not show a major shift, but a minor ~10 nm red-shift, upon increasing silver content. Themore » intensity of the SPR peak also varies in an intriguing manner, where a dampening is observed with medium silver incorporation, and a significant sharpening is observed upon higher Ag content. The report outlines (a) an unprecedented advance in nanoparticle mass spectrometry of high mass at atomic precision; and (b) the unexpected optical behavior of Au–Ag alloys in the region where nascent SPR emerges; specifically, in this work, the SPR-like peak does not show a major ~100 nm blue-shift with Ag alloying of Au 329 nanomolecules, as shown to be common in larger nanoparticles.« less

The management of breakthrough cancer pain--educational needs a European nursing survey.

PubMed

Wengström, Y; Rundström, C; Geerling, J; Pappa, T; Weisse, I; Williams, S C; Zavratnik, B; Rustøen, T

2014-01-01

Poorly managed cancer pain is well known to profoundly impact the patient's daily life and interfere with quality of life. Nurses who cared for patients with cancer from 12 European countries participated in a survey of breakthrough cancer pain practice. The purpose was to investigate how nurses assess breakthrough cancer pain, use of standardised tools, confidence in supporting patients and awareness of medications. Responses from 1241 participants showed country variations. The majority of the sample was female, Germany had the highest proportion of male nurses (21.0%), followed by Greece (15.8%). A significantly larger proportion of nurses with longer experience and more education (78.8%) used a comprehensive definition of breakthrough cancer pain. Significant variations in training were found; 71% of Finnish nurses had received training compared with 6% of Greek nurses. Training and using a standardised assessment tool was associated with a significant increase in the nurses' perceived ability to distinguish between breakthrough and background pain. Nurses in countries with the highest proportion of training were most confident in supporting patients. In conclusion, there still exists problems with effective management of patients' breakthrough cancer pain, continuing inability to define the difference between background and breakthrough cancer pain leads to poor treatment. © 2013 John Wiley & Sons Ltd.

[Effect of Below-cloud Secondary Evaporation in Precipitations over the Loess Plateau Based on the Stable Isotopes of Hydrogen and Oxygen].

PubMed

Jin, Xiao-gang; Zhang, Ming-jun; Wang, Sheng-jie; Zhu, Xiao-fan; Dong, Lei; Ren, Zheng-guo; Chen, Fen-li

2015-04-01

Based on stable isotopes in 409 precipitation samples provided by GNIP and meteorological records at the eight stations in Loess Plateau from January 1985 to December 2004, as well as the trajectory model of HYSPLIT 4.9, the spatial and temporal variations of d-excess and Δ18O were analyzed. The spatial distribution of secondary evaporation rate and the impact of meteorological factors on below-cloud secondary evaporation were also discussed. The result showed that: (1) During summer and winter monsoon periods, Δ18O showed an uptrend variation and d-excess showed a downtrend variation from south to north in Loess Plateau. From east to west, Δ180 showed an uptrend variation only in summer monsoon period and a downtrend variation in winter monsoon period. The value of d-excess also showed a downtrend variation. Amplitude of variation Δ18O and d-excess could indicate the routes of monsoon. (2) Secondary evaporation existed on an annual basis, and it was relatively significant during the summer monsoon period, with ranges from 1.51% to 5.88% and an average rate of 3.87%. While winter monsoon became lower, the rates ranged from 1.06% to 5.46%, and the average rate dropped to 3.03%. Monsoon had larger influence on secondary evaporation in margin area of the plateau, while the influence on the central stations was little. (3) Temperature had the highest contribution to secondary evaporation, followed by precipitation amount and water vapor pressure, and relative humidity had a small contribution. Moreover, the influence of wind speed and altitude on secondary evaporation was weak.

Task-dependent signal variations in EEG error-related potentials for brain-computer interfaces.

PubMed

Iturrate, I; Montesano, L; Minguez, J

2013-04-01

A major difficulty of brain-computer interface (BCI) technology is dealing with the noise of EEG and its signal variations. Previous works studied time-dependent non-stationarities for BCIs in which the user's mental task was independent of the device operation (e.g., the mental task was motor imagery and the operational task was a speller). However, there are some BCIs, such as those based on error-related potentials, where the mental and operational tasks are dependent (e.g., the mental task is to assess the device action and the operational task is the device action itself). The dependence between the mental task and the device operation could introduce a new source of signal variations when the operational task changes, which has not been studied yet. The aim of this study is to analyse task-dependent signal variations and their effect on EEG error-related potentials. The work analyses the EEG variations on the three design steps of BCIs: an electrophysiology study to characterize the existence of these variations, a feature distribution analysis and a single-trial classification analysis to measure the impact on the final BCI performance. The results demonstrate that a change in the operational task produces variations in the potentials, even when EEG activity exclusively originated in brain areas related to error processing is considered. Consequently, the extracted features from the signals vary, and a classifier trained with one operational task presents a significant loss of performance for other tasks, requiring calibration or adaptation for each new task. In addition, a new calibration for each of the studied tasks rapidly outperforms adaptive techniques designed in the literature to mitigate the EEG time-dependent non-stationarities.

Demographic behavior and the welfare state: econometric issues in the identification of the effects of tax and transfer programs.

PubMed

Moffitt, R

1989-01-01

It is difficult and risky to identify the effects of tax and transfer programs on demographic behavior. The primary concern of this article is to see if real exogenous variation in these programs' parameters exist to adequately evaluate the effects of the programs on behavior. A 1982 study examined the effect of the Aid to Families with Dependent Children (AFDC), a commonly used example of a US transfer program, on the probability that a female heads a household of children 18 years old with no adult male present. The dependent variable merged household, marital status, and fertility choice into 1 variable. The independent variables included leisure hours and income which also defined a woman's utility function. In this study, the parameters used to represent AFDC effects were not only identified by variation in the AFDC variables. 2 other studies attempting to examine AFDC's effects on demographic behavior (Hutchens [1979] and Ellwood and Bane [1985]) also failed to identify these effects. Ellwood and Bane appropriately concentrated on exogenous program variation (since benefits vary from state to state) and how it might be used in evaluating the effects of AFDC on behavior. They erroneously determined, however, that state variation should not be considered in their model. The studies reviewed in this article looked at AFDC, a program with significant intracountry parameter variation, yet these studies relied on potentially illegitimate sources of variation. Intracountry program variation is less likely to occur in Western Europe and therefore the problem of identifying effects of tax and transfer programs on demographic behavior is apt to be even more severe. Any further such studies should address these issues.

Ecology of Lake Superior: Linking Landscape to Nearshore Condition

EPA Science Inventory

High spatial variation is well known to exist in water quality parameters of the Great Lakes nearshore, however strong patterns for extended reaches are also observed and found to be robust across a seasonal time frame. Less is known about robustness of inter-annual variation wi...

Evaluation of functional variation in candidate genes for pork quality

USDA-ARS?s Scientific Manuscript database

Considerable variation exists in pork quality traits and consumer perception of pork eating satisfaction is largely driven by tenderness and sensory juiciness scores, which are related to shear force, cooking loss and ultimate pH. Water loss from meat during postmortem storage reduces profitability ...

Lake Superior: Nearshore Variability and a Landscape Driver Concept

EPA Science Inventory

High spatial variation is well known to exist in water quality parameters of the Great Lakes nearshore, however strong patterns for extended reaches are also observed and found to be robust across a seasonal time frame. Less is known about robustness of inter-annual variation wi...

Spatio-temporal variation of methane over Indian region: Seasonal and inter-annual variation .

NASA Astrophysics Data System (ADS)

M, K.; Nair, P. R.

2015-12-01

Methane (CH4) has an important role in the radiation budget and chemistry in the lower and middle atmosphere as a greenhouse and reactive trace gas. The rapid developments in the agriculture and industry over India have lead to the emission of many pollutants like CO, O3, CH4, CO2, SO2 etc into the atmosphere. However, their sources, sinks and concentration levels are poorly understood because of the lack of systematic sampling and monitoring. The advent of satellite remote sensing has helped to analyze the chemical composition of atmosphere with good spatial coverage especially over tropical region which was poorly sampled with the existing surface network. This work attempts an analysis of spatial distribution, seasonal cycle and inter annual variation of CH4 over Indian region during 2003-2009 using SCIAMACHY data onboard ENVISAT. Column CH4 varies from 1740-1890 ppbv over Indian region with distinct spatial and temporal features. We observed a dependence of seasonal CH4 variation on rice cultivation, convective activities and changes in boundary layer characteristics. The comparative study using satellite, aircraft and surface measurement shown CH4 has non-homogeneity in its distribution and seasonal variation in different layers of atmosphere. A comparative study of CH4 at different hot spot regions over the globe was carried out which showed prominent hemispherical variations. Large spread in column CH4 was observed at India and Chinese region compared to other regions with a significant seasonal variability. This study points to the blending of satellite, aircraft and surface measurements for the realization of regional distribution of CH4.

Variational processes and stochastic versions of mechanics

NASA Astrophysics Data System (ADS)

Zambrini, J. C.

1986-09-01

The dynamical structure of any reasonable stochastic version of classical mechanics is investigated, including the version created by Nelson [E. Nelson, Quantum Fluctuations (Princeton U.P., Princeton, NJ, 1985); Phys. Rev. 150, 1079 (1966)] for the description of quantum phenomena. Two different theories result from this common structure. One of them is the imaginary time version of Nelson's theory, whose existence was unknown, and yields a radically new probabilistic interpretation of the heat equation. The existence and uniqueness of all the involved stochastic processes is shown under conditions suggested by the variational approach of Yasue [K. Yasue, J. Math. Phys. 22, 1010 (1981)].

Abstract generalized vector quasi-equilibrium problems in noncompact Hadamard manifolds.

PubMed

Lu, Haishu; Wang, Zhihua

2017-01-01

This paper deals with the abstract generalized vector quasi-equilibrium problem in noncompact Hadamard manifolds. We prove the existence of solutions to the abstract generalized vector quasi-equilibrium problem under suitable conditions and provide applications to an abstract vector quasi-equilibrium problem, a generalized scalar equilibrium problem, a scalar equilibrium problem, and a perturbed saddle point problem. Finally, as an application of the existence of solutions to the generalized scalar equilibrium problem, we obtain a weakly mixed variational inequality and two mixed variational inequalities. The results presented in this paper unify and generalize many known results in the literature.

Abundance differences among globular-cluster giants: Primordial versus evolutionary scenarios

NASA Astrophysics Data System (ADS)

Kraft, Robert P.

1994-06-01

Contrary to historical expectation, stars within a given globular cluster often exhibit wide variations in the abundance of C, N, and O as well as certain light metals, particularly Na and Al. Owing to flux limitations, studies have been confined to evolved stars, especially giants, but in few instances variations have been detected among main-sequence stars. Among giants, the variations are of two kinds. The abundances of C and N are often anticorrelated, and in the limited number of cases in which both have been measured, O and N abundances have also often proved to be anticorrelated (Pilachowski 1988; Sneden et al. 1991; Brown et al. 1991; Kraft et al. 1992). Following pioneering work by Cohen (1978) and Peterson (1980), strong evidence has recently emerged for the existence of a significant global anticorrelation between O and Na abundances (Drake et al. 1992, Kraft et al. 1993). The observations are discussed in terms of contrasting hypotheses: evolutionary versus primordial. In the former, the variations are attributed to the dredgeup of material that has been processed through the CNO cycle in the globular-cluster stars themselves. In the latter, the variations are attributed to primordial chemical inhomogeneities in the material out of which the cluster stars were formed, the composition of these 'clumps' having been determined by nuclear processing in a prior generation of more massive stars. Observational evidence supporting each of these scenarios is cited. Recent studies of stellar rotation among horizontal branch stars in certain clusters (Peterson et al. 1994) as well as new calculations of Na-23 and Al-27 production in the CNO processing regions of evolving low-mass giants (Langer et al. 1993) lend fresh support to the evolutionary hypothesis. However, such calculations do not explain the variation of C and N abundances found among cluster main-sequence stars (Suntzeff 1989; Briley et al. 1991) which therefore seem explicable only on the basis of a primordial scenario. Among mildly metal-poor giants, i.e., those in the range from solar metallicity to (Fe/H) approximately -1, recent observational evidence suggesting the existence of a substructure in the (el/Fe) ratios of the heavier alpha elements, e.g., Si, Mg, Ca, and Ti, is discussed. The possible influence of this effect on the interpretation of the integrated spectra of extragalactic globular clusters and E galaxies is noted.

LANDSAT-4 band 6 data evaluation

NASA Technical Reports Server (NTRS)

1983-01-01

The radiometric integrity of the LANDSAT-D thematic mapper (TM) thermal infrared channel (band 6) data was evaluated to develop improved radiometric preprocessing calibration techniques for removal of atmospheric effects. Primary data analysis was spent in evaluating the line to line and detector to detector variation in the thermal infrared data. The data studied was in the core area of Lake Ontario where very stable temperatures were expected. The detectors and the scan direction were taken as separate parameters and an analysis of variance was conducted. The data indicate that significant variability exists both between detectors and between scan directions.

Stratospheric water vapor feedback.

PubMed

Dessler, A E; Schoeberl, M R; Wang, T; Davis, S M; Rosenlof, K H

2013-11-05

We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric water vapor feedback. We estimate the strength of this feedback in a chemistry-climate model to be +0.3 W/(m(2)⋅K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause.

Epidemiology and Disparities in Care: The Impact of Socioeconomic Status, Gender, and Race on the Presentation, Management, and Outcomes of Patients Undergoing Ventral Hernia Repair.

PubMed

Cherla, Deepa V; Poulose, Benjamin; Prabhu, Ajita S

2018-06-01

More research is needed with regards to gender, race, and socioeconomic status on ventral hernia presentation, management, and outcomes. The role of culture and geography in hernia-related health care remains unknown. Currently existing nationwide registries have thus far yielded at best a modest overview of disparities in hernia care. The significant variation in care relative to gender, race, and socioeconomic status suggests that there is room for improvement in providing consistent care for patients with hernias. Copyright © 2018 Elsevier Inc. All rights reserved.

Joint inversion for transponder localization and sound-speed profile temporal variation in high-precision acoustic surveys.

PubMed

Li, Zhao; Dosso, Stan E; Sun, Dajun

2016-07-01

This letter develops a Bayesian inversion for localizing underwater acoustic transponders using a surface ship which compensates for sound-speed profile (SSP) temporal variation during the survey. The method is based on dividing observed acoustic travel-time data into time segments and including depth-independent SSP variations for each segment as additional unknown parameters to approximate the SSP temporal variation. SSP variations are estimated jointly with transponder locations, rather than calculated separately as in existing two-step inversions. Simulation and sea-trial results show this localization/SSP joint inversion performs better than two-step inversion in terms of localization accuracy, agreement with measured SSP variations, and computational efficiency.

Population-level genetic variation and climate change in a biodiversity hotspot

PubMed Central

2017-01-01

Introduction Estimated future climate scenarios can be used to predict where hotspots of endemism may occur over the next century, but life history, ecological and genetic traits will be important in informing the varying responses within myriad taxa. Essential to predicting the consequences of climate change to individual species will be an understanding of the factors that drive genetic structure within and among populations. Here, I review the factors that influence the genetic structure of plant species in California, but are applicable elsewhere; existing levels of genetic variation, life history and ecological characteristics will affect the ability of an individual taxon to persist in the presence of anthropogenic change. Factors influencing the distribution of genetic variation Persistence in the face of climate change is likely determined by life history characteristics: dispersal ability, generation time, reproductive ability, degree of habitat specialization, plant–insect interactions, existing genetic diversity and availability of habitat or migration corridors. Existing levels of genetic diversity in plant populations vary based on a number of evolutionary scenarios that include endemism, expansion since the last glacial maximum, breeding system and current range sizes. Regional priorities and examples A number of well-documented examples are provided from the California Floristic Province. Some predictions can be made for the responses of plant taxa to rapid environmental changes based on geographic position, evolutionary history, existing genetic variation, and ecological amplitude. Conclusions, Solutions and Recommendations The prediction of how species will respond to climate change will require a synthesis drawing from population genetics, geography, palaeontology and ecology. The important integration of the historical factors that have shaped the distribution and existing genetic structure of California’s plant taxa will enable us to predict and prioritize the conservation of species and areas most likely to be impacted by rapid climate change, human disturbance and invasive species. PMID:28069633

Research participant compensation: A matter of statistical inference as well as ethics.

PubMed

Swanson, David M; Betensky, Rebecca A

2015-11-01

The ethics of compensation of research subjects for participation in clinical trials has been debated for years. One ethical issue of concern is variation among subjects in the level of compensation for identical treatments. Surprisingly, the impact of variation on the statistical inferences made from trial results has not been examined. We seek to identify how variation in compensation may influence any existing dependent censoring in clinical trials, thereby also influencing inference about the survival curve, hazard ratio, or other measures of treatment efficacy. In simulation studies, we consider a model for how compensation structure may influence the censoring model. Under existing dependent censoring, we estimate survival curves under different compensation structures and observe how these structures induce variability in the estimates. We show through this model that if the compensation structure affects the censoring model and dependent censoring is present, then variation in that structure induces variation in the estimates and affects the accuracy of estimation and inference on treatment efficacy. From the perspectives of both ethics and statistical inference, standardization and transparency in the compensation of participants in clinical trials are warranted. Copyright © 2015 Elsevier Inc. All rights reserved.

A dynamic unilateral contact problem with adhesion and friction in viscoelasticity

NASA Astrophysics Data System (ADS)

Cocou, Marius; Schryve, Mathieu; Raous, Michel

2010-08-01

The aim of this paper is to study an interaction law coupling recoverable adhesion, friction and unilateral contact between two viscoelastic bodies of Kelvin-Voigt type. A dynamic contact problem with adhesion and nonlocal friction is considered and its variational formulation is written as the coupling between an implicit variational inequality and a parabolic variational inequality describing the evolution of the intensity of adhesion. The existence and approximation of variational solutions are analysed, based on a penalty method, some abstract results and compactness properties. Finally, some numerical examples are presented.

Local time, seasonal, and solar cycle dependency of longitudinal variations of TEC along the crest of EIA over India

NASA Astrophysics Data System (ADS)

Sunda, Surendra; Vyas, B. M.

2013-10-01

global wave number 4 structure in the Indian longitudinal region spanning from ~70 to 95°E forming the upward slope of the peak in the total electron content (TEC) are reported along the crest of equatorial ionization anomaly (EIA). The continuous and simultaneous measurements from five GPS stations of GPS Aided Geo Augmented Navigation (GAGAN) network are used in this study. The long-term database (2004-2012) is utilized for examining the local time, seasonal, and solar cycle dependency on the longitudinal variations of TEC. Our results confirm the existence of longitudinal variations of TEC in accordance with wave number 4 longitudinal structure including its strength. The results suggest that these variations, in general, start to develop at ~09 LT, achieve maximum strength at 12-15 LT, and decay thereafter, the decay rate depending on the season. They are more pronounced in equinoctial season followed by summer and winter. The longitudinal variations persist beyond midnight in equinox seasons, whereas in winter, they are conspicuously absent. Interestingly, they also exhibit significant solar cycle dependence in the solstices, whereas in the equinoxes, they are independent of solar activity. The comparison of crest-to-trough ratio (CTR) in the eastern (92°E) and western (72°E) extreme longitudes reveals higher CTR on the eastern side than over the western extreme, suggesting the role of nonmigrating tides in modulating the ExB vertical drift and the consequential EIA crest formation.

Variational energy principle for compressible, baroclinic flow. 2: Free-energy form of Hamilton's principle

NASA Technical Reports Server (NTRS)

Schmid, L. A.

1977-01-01

The first and second variations are calculated for the irreducible form of Hamilton's Principle that involves the minimum number of dependent variables necessary to describe the kinetmatics and thermodynamics of inviscid, compressible, baroclinic flow in a specified gravitational field. The form of the second variation shows that, in the neighborhood of a stationary point that corresponds to physically stable flow, the action integral is a complex saddle surface in parameter space. There exists a form of Hamilton's Principle for which a direct solution of a flow problem is possible. This second form is related to the first by a Friedrichs transformation of the thermodynamic variables. This introduces an extra dependent variable, but the first and second variations are shown to have direct physical significance, namely they are equal to the free energy of fluctuations about the equilibrium flow that satisfies the equations of motion. If this equilibrium flow is physically stable, and if a very weak second order integral constraint on the correlation between the fluctuations of otherwise independent variables is satisfied, then the second variation of the action integral for this free energy form of Hamilton's Principle is positive-definite, so the action integral is a minimum, and can serve as the basis for a direct trail and error solution. The second order integral constraint states that the unavailable energy must be maximum at equilibrium, i.e. the fluctuations must be so correlated as to produce a second order decrease in the total unavailable energy.

BayesPI-BAR: a new biophysical model for characterization of regulatory sequence variations

PubMed Central

Wang, Junbai; Batmanov, Kirill

2015-01-01

Sequence variations in regulatory DNA regions are known to cause functionally important consequences for gene expression. DNA sequence variations may have an essential role in determining phenotypes and may be linked to disease; however, their identification through analysis of massive genome-wide sequencing data is a great challenge. In this work, a new computational pipeline, a Bayesian method for protein–DNA interaction with binding affinity ranking (BayesPI-BAR), is proposed for quantifying the effect of sequence variations on protein binding. BayesPI-BAR uses biophysical modeling of protein–DNA interactions to predict single nucleotide polymorphisms (SNPs) that cause significant changes in the binding affinity of a regulatory region for transcription factors (TFs). The method includes two new parameters (TF chemical potentials or protein concentrations and direct TF binding targets) that are neglected by previous methods. The new method is verified on 67 known human regulatory SNPs, of which 47 (70%) have predicted true TFs ranked in the top 10. Importantly, the performance of BayesPI-BAR, which uses principal component analysis to integrate multiple predictions from various TF chemical potentials, is found to be better than that of existing programs, such as sTRAP and is-rSNP, when evaluated on the same SNPs. BayesPI-BAR is a publicly available tool and is able to carry out parallelized computation, which helps to investigate a large number of TFs or SNPs and to detect disease-associated regulatory sequence variations in the sea of genome-wide noncoding regions. PMID:26202972

Towards Comprehensive Variation Models for Designing Vehicle Monitoring Systems

NASA Technical Reports Server (NTRS)

McAdams, Daniel A.; Tumer, Irem Y.; Clancy, Daniel (Technical Monitor)

2002-01-01

When designing vehicle vibration monitoring systems for aerospace devices, it is common to use well-established models of vibration features to determine whether failures or defects exist. Most of the algorithms used for failure detection rely on these models to detect significant changes in a flight environment. In actual practice, however, most vehicle vibration monitoring systems are corrupted by high rates of false alarms and missed detections. This crucial roadblock makes their implementation in real vehicles (e.g., helicopter transmissions and aircraft engines) difficult, making their operation costly and unreliable. Research conducted at the NASA Ames Research Center has determined that a major reason for the high rates of false alarms and missed detections is the numerous sources of statistical variations that are not taken into account in the modeling assumptions. In this paper, we address one such source of variations, namely, those caused during the design and manufacturing of rotating machinery components that make up aerospace systems. We present a novel way of modeling the vibration response by including design variations via probabilistic methods. Using such models, we develop a methodology to account for design and manufacturing variations, and explore the changes in the vibration response to determine its stochastic nature. We explore the potential of the methodology using a nonlinear cam-follower model, where the spring stiffness values are assumed to follow a normal distribution. The results demonstrate initial feasibility of the method, showing great promise in developing a general methodology for designing more accurate aerospace vehicle monitoring systems.

Packing microstructure and local density variations of experimental and computational pebble beds

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

Auwerda, G. J.; Kloosterman, J. L.; Lathouwers, D.

2012-07-01

In pebble bed type nuclear reactors the fuel is contained in graphite pebbles, which form a randomly stacked bed with a non-uniform packing density. These variations can influence local coolant flow and power density and are a possible cause of hotspots. To analyse local density variations computational methods are needed that can generate randomly stacked pebble beds with a realistic packing structure on a pebble-to-pebble level. We first compare various properties of the local packing structure of a computed bed with those of an image made using computer aided X-ray tomography, looking at properties in the bulk of the bedmore » and near the wall separately. Especially for the bulk of the bed, properties of the computed bed show good comparison with the scanned bed and with literature, giving confidence our method generates beds with realistic packing microstructure. Results also show the packing structure is different near the wall than in the bulk of the bed, with pebbles near the wall forming ordered layers similar to hexagonal close packing. Next, variations in the local packing density are investigated by comparing probability density functions of the packing fraction of small clusters of pebbles throughout the bed. Especially near the wall large variations in local packing fractions exists, with a higher probability for both clusters of pebbles with low (<0.6) and high (>0.65) packing fraction, which could significantly affect flow rates and, together with higher power densities, could result in hotspots. (authors)« less

Geographic variations in avoidable hospitalizations in the elderly, in a health system with universal coverage

PubMed Central

Magan, Purificacion; Otero, Angel; Alberquilla, Angel; Ribera, Jose Manuel

2008-01-01

Background The study of Hospitalizations for ambulatory care sensitive conditions (ACSH) has been proposed as an indirect measure of access to and receipt of care by older persons at the entryway to the Spanish public health system. The aim of this work is to identify the rates of ACSH in persons 65 years or older living in different small-areas of the Community of Madrid (CM) and to detect possible differences in ACSH. Methods Cross-sectional, ecologic study, which covered all 34 health districts of the CM. The study population consisted of all individuals aged 65 years or older residing in the CM between 2001 and 2003, inclusive. Using hospital discharge data, avoidable ACSH were selected from the list of conditions validated for Spain. Age- and sex-adjusted ACSH rates were calculated for the population of each health district and the statistics describing the data variability. Point graphs and maps were designed to represent the ACSH rates in the different health districts. Results Of all the hospitalizations, 16.5% (64,409) were ACSH. Globally, the rate was higher among men: 33.15 per 1,000 populations vs. 22.10 in women and these differences were statistically significant (p < 0.05) in each district. For men the range was 70.82 and the coefficient of variation (CV) was 0.47, while for women the range was 43.69 and the CV was 0.48. In 93.1% of cases, the ACSH were caused by hypertensive cardiovascular disease, heart failure or pneumonia. A centripetal pattern can be observed, with lower rates in the districts in the center of the CM. This geographic distribution is maintained after grouping by sex. Conclusion A significant variation is demonstrated in "preventable" hospitalizations between the different districts. In all the districts the men present rates significantly higher than women. Important variations in the access are observed the Primary Attention in spite of existing a universal sanitary cover. PMID:18282282

Contribution of common non-synonymous variants in PCSK1 to body mass index variation and risk of obesity: a systematic review and meta-analysis with evidence from up to 331 175 individuals.

PubMed

Nead, Kevin T; Li, Aihua; Wehner, Mackenzie R; Neupane, Binod; Gustafsson, Stefan; Butterworth, Adam; Engert, James C; Davis, A Darlene; Hegele, Robert A; Miller, Ruby; den Hoed, Marcel; Khaw, Kay-Tee; Kilpeläinen, Tuomas O; Wareham, Nick; Edwards, Todd L; Hallmans, Göran; Varga, Tibor V; Kardia, Sharon L R; Smith, Jennifer A; Zhao, Wei; Faul, Jessica D; Weir, David; Mi, Jie; Xi, Bo; Quinteros, Samuel Canizales; Cooper, Cyrus; Sayer, Avan Aihie; Jameson, Karen; Grøntved, Anders; Fornage, Myriam; Sidney, Stephen; Hanis, Craig L; Highland, Heather M; Häring, Hans-Ulrich; Heni, Martin; Lasky-Su, Jessica; Weiss, Scott T; Gerhard, Glenn S; Still, Christopher; Melka, Melkaey M; Pausova, Zdenka; Paus, Tomáš; Grant, Struan F A; Hakonarson, Hakon; Price, R Arlen; Wang, Kai; Scherag, Andre; Hebebrand, Johannes; Hinney, Anke; Franks, Paul W; Frayling, Timothy M; McCarthy, Mark I; Hirschhorn, Joel N; Loos, Ruth J; Ingelsson, Erik; Gerstein, Hertzel C; Yusuf, Salim; Beyene, Joseph; Anand, Sonia S; Meyre, David

2015-06-15

Polymorphisms rs6232 and rs6234/rs6235 in PCSK1 have been associated with extreme obesity [e.g. body mass index (BMI) ≥ 40 kg/m(2)], but their contribution to common obesity (BMI ≥ 30 kg/m(2)) and BMI variation in a multi-ethnic context is unclear. To fill this gap, we collected phenotypic and genetic data in up to 331 175 individuals from diverse ethnic groups. This process involved a systematic review of the literature in PubMed, Web of Science, Embase and the NIH GWAS catalog complemented by data extraction from pre-existing GWAS or custom-arrays in consortia and single studies. We employed recently developed global meta-analytic random-effects methods to calculate summary odds ratios (OR) and 95% confidence intervals (CIs) or beta estimates and standard errors (SE) for the obesity status and BMI analyses, respectively. Significant associations were found with binary obesity status for rs6232 (OR = 1.15, 95% CI 1.06-1.24, P = 6.08 × 10(-6)) and rs6234/rs6235 (OR = 1.07, 95% CI 1.04-1.10, P = 3.00 × 10(-7)). Similarly, significant associations were found with continuous BMI for rs6232 (β = 0.03, 95% CI 0.00-0.07; P = 0.047) and rs6234/rs6235 (β = 0.02, 95% CI 0.00-0.03; P = 5.57 × 10(-4)). Ethnicity, age and study ascertainment significantly modulated the association of PCSK1 polymorphisms with obesity. In summary, we demonstrate evidence that common gene variation in PCSK1 contributes to BMI variation and susceptibility to common obesity in the largest known meta-analysis published to date in genetic epidemiology. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Contribution of common non-synonymous variants in PCSK1 to body mass index variation and risk of obesity: a systematic review and meta-analysis with evidence from up to 331 175 individuals

PubMed Central

Nead, Kevin T.; Li, Aihua; Wehner, Mackenzie R.; Neupane, Binod; Gustafsson, Stefan; Butterworth, Adam; Engert, James C.; Davis, A. Darlene; Hegele, Robert A.; Miller, Ruby; den Hoed, Marcel; Khaw, Kay-Tee; Kilpeläinen, Tuomas O.; Wareham, Nick; Edwards, Todd L.; Hallmans, Göran; Varga, Tibor V.; Kardia, Sharon L. R.; Smith, Jennifer A.; Zhao, Wei; Faul, Jessica D.; Weir, David; Mi, Jie; Xi, Bo; Quinteros, Samuel Canizales; Cooper, Cyrus; Sayer, Avan Aihie; Jameson, Karen; Grøntved, Anders; Fornage, Myriam; Sidney, Stephen; Hanis, Craig L.; Highland, Heather M.; Häring, Hans-Ulrich; Heni, Martin; Lasky-Su, Jessica; Weiss, Scott T.; Gerhard, Glenn S.; Still, Christopher; Melka, Melkaey M.; Pausova, Zdenka; Paus, Tomáš; Grant, Struan F. A.; Hakonarson, Hakon; Price, R. Arlen; Wang, Kai; Scherag, Andre; Hebebrand, Johannes; Hinney, Anke; Franks, Paul W.; Frayling, Timothy M.; McCarthy, Mark I.; Hirschhorn, Joel N.; Loos, Ruth J.; Ingelsson, Erik; Gerstein, Hertzel C.; Yusuf, Salim; Beyene, Joseph; Anand, Sonia S.; Meyre, David

2015-01-01

Polymorphisms rs6232 and rs6234/rs6235 in PCSK1 have been associated with extreme obesity [e.g. body mass index (BMI) ≥ 40 kg/m2], but their contribution to common obesity (BMI ≥ 30 kg/m2) and BMI variation in a multi-ethnic context is unclear. To fill this gap, we collected phenotypic and genetic data in up to 331 175 individuals from diverse ethnic groups. This process involved a systematic review of the literature in PubMed, Web of Science, Embase and the NIH GWAS catalog complemented by data extraction from pre-existing GWAS or custom-arrays in consortia and single studies. We employed recently developed global meta-analytic random-effects methods to calculate summary odds ratios (OR) and 95% confidence intervals (CIs) or beta estimates and standard errors (SE) for the obesity status and BMI analyses, respectively. Significant associations were found with binary obesity status for rs6232 (OR = 1.15, 95% CI 1.06–1.24, P = 6.08 × 10−6) and rs6234/rs6235 (OR = 1.07, 95% CI 1.04–1.10, P = 3.00 × 10−7). Similarly, significant associations were found with continuous BMI for rs6232 (β = 0.03, 95% CI 0.00–0.07; P = 0.047) and rs6234/rs6235 (β = 0.02, 95% CI 0.00–0.03; P = 5.57 × 10−4). Ethnicity, age and study ascertainment significantly modulated the association of PCSK1 polymorphisms with obesity. In summary, we demonstrate evidence that common gene variation in PCSK1 contributes to BMI variation and susceptibility to common obesity in the largest known meta-analysis published to date in genetic epidemiology. PMID:25784503

Center variation in the use of nonstandardized model for end-stage liver disease exception points.

PubMed

Goldberg, David S; Makar, George; Bittermann, Therese; French, Benjamin

2013-12-01

The Model for End-Stage Liver Disease (MELD) score is an imperfect prognosticator of waitlist dropout, so transplant centers may apply for exception points to increase a waitlist candidate's priority on the waitlist. Exception applications are categorized as recognized exceptional diagnoses (REDs; eg, hepatocellular carcinoma) and non-REDs (eg, cholangitis). Although prior work has demonstrated regional variation in the use of exceptions, no work has examined the between-center variability. We analyzed all new waitlist candidates from February 27, 2002 to June 3, 2011 to explore variations in the use of non-REDs, for which no strict exception criteria exist. There were 58,641 new waitlist candidates, and 4356 (7.4%) applied for a non-RED exception. The number of applications increased steadily over time, as did the approval rates for such applications: from <50% in 2002 to nearly 75% in 2010. When we adjusted for patient factors, there was significant variability (P < 0.001) in the use of non-RED exceptions in 8 of 11 United Network for Organ Sharing (UNOS) regions and in the approval of these exceptions in 6 of 11 UNOS regions. The variability in the use and approval of non-REDs was clinically significant: waitlist candidates with approved exceptions were significantly more likely to undergo transplantation (68.3% versus 53.4%, P < 0.001) and were less likely to be removed for death or clinical deterioration (10.4% versus 16.2%, P < 0.001). Increased median MELD score at transplantation within a donor service area was the only center factor associated with increased odds of applying for exceptions, while no center factors were associated with having non-RED exceptions approved. Further work is needed to identify other sources of variation to ensure the appropriate and equitable use of non-RED exceptions. © 2013 American Association for the Study of Liver Diseases.

Viable progeny from crosses between geographically isolated populations of Podisus (Hemiptera: Pentatomidae) indicate a single species

USDA-ARS?s Scientific Manuscript database

Discrepancies in reports on the presence of Podisus maculiventris (Say) (Hemiptera: Pentatomidae) in the western region of USA, and morphological variations of the species brought into question whether the species existed west of the Rocky Mountains. In this study, morphological variations in color ...

Evidence of bottleneck and isolation by distance in an endangered species from the Tropical Andean hotspot

USDA-ARS?s Scientific Manuscript database

The Tropical Andes is the most diverse of the recognized plant conservation hotspots. In contrast, there exists scant knowledge about patterns of genetic variation within its constituent species. Understanding genetic variation is essential to develop successful conservation plans. Phaedranassa tun...

Preschool Language Variation, Growth, and Predictors in Children on the Autism Spectrum

ERIC Educational Resources Information Center

Ellis Weismer, Susan; Kover, Sara T.

2015-01-01

Background: There is wide variation in language abilities among young children with autism spectrum disorders (ASD), with some toddlers developing age-appropriate language while others remain minimally verbal after age 5. Conflicting findings exist regarding predictors of language outcomes in ASD and various methodological issues limit the…

A First Step towards Variational Methods in Engineering

ERIC Educational Resources Information Center

Periago, Francisco

2003-01-01

In this paper, a didactical proposal is presented to introduce the variational methods for solving boundary value problems to engineering students. Starting from a couple of simple models arising in linear elasticity and heat diffusion, the concept of weak solution for these models is motivated and the existence, uniqueness and continuous…

Lake Superior: Nearshore Variability and a Landscape Driver Concept (journal article)

EPA Science Inventory

Spatial variation is well known to exist in water quality parameters of the Great Lakes nearshore, however strong patterns for extended reaches also have been observed and found to be robust across seasonal time frames. Less is known about robustness of inter-annual variation wi...

A Call for an Empirical Taxonomy of Schools

ERIC Educational Resources Information Center

Van Ryzin, Mark J.

2008-01-01

Many educational researchers have identified issues on classifying schools and some have made use of ad-hoc classification systems in their analyses; however, these solutions are generally one-dimensional, which prohibits them from capturing the full breadth of variation among schools. To understand the amount of variation that exist in schools…

Characterization of newly identified natural high-oleate mutant from the USDA cultivated peanut germplasm collection

USDA-ARS?s Scientific Manuscript database

In plants and animals, natural genetic variation may exist in germplasm collection. Mining and utilizing this variation may provide benefits for new breed/cultivar development. From screening over 4,000 cultivated peanut germplasm accessions, we identified two natural mutant lines with 80% oleic aci...

Larger CO2 source at the equatorial Pacific during the last deglaciation

PubMed Central

Kubota, Kaoru; Yokoyama, Yusuke; Ishikawa, Tsuyoshi; Obrochta, Stephen; Suzuki, Atsushi

2014-01-01

While biogeochemical and physical processes in the Southern Ocean are thought to be central to atmospheric CO2 rise during the last deglaciation, the role of the equatorial Pacific, where the largest CO2 source exists at present, remains largely unconstrained. Here we present seawater pH and pCO2 variations from fossil Porites corals in the mid equatorial Pacific offshore Tahiti based on a newly calibrated boron isotope paleo-pH proxy. Our new data, together with recalibrated existing data, indicate that a significant pCO2 increase (pH decrease), accompanied by anomalously large marine 14C reservoir ages, occurred following not only the Younger Dryas, but also Heinrich Stadial 1. These findings indicate an expanded zone of equatorial upwelling and resultant CO2 emission, which may be derived from higher subsurface dissolved inorganic carbon concentration. PMID:24918354

The physics and chemistry of the L134N molecular core

NASA Technical Reports Server (NTRS)

Swade, Daryl A.

1989-01-01

The dark cloud L134N is studied in detail via millimeter- and centimeter-wavelength emission-line spectra. A high-density core of molecular gas exists in L134N which has a kinetic temperature of about 12 K, a peak molecular hydrogen density of about 10 exp 4.5/cu cm, and a mass of about 23 solar. The core may be the site of future star formation. Maps of emission from (C-18)O, CS, H(C-13)O(+), SO, NH3, and C3H2 reveal morphologically different distributions resulting in part from both varying physical conditions within the cloud and optical depth effects. Significant differences also exist which are probably due to chemical abundance variations. A consistent set of LTE chemical abundances has been estimated at as many as seven positions, which can be used to constrain chemical models of dark clouds.

The prevalence of psychopathology in siblings of children with mental health problems: a 20-year systematic review.

PubMed

Ma, Nylanda; Roberts, Rachel; Winefield, Helen; Furber, Gareth

2015-02-01

While the importance of looking at the entire family system in the context of child and adolescent mental health is well recognised, siblings of children with mental health problems (MHPs) are often overlooked. The existing literature on the mental health of these siblings needs to be reviewed. A systematic search located publications from 1990 to 2011 in four electronic databases. Thirty-nine relevant studies reported data on the prevalence of psychopathology in siblings of target children with MHPs. Siblings of target children had higher rates of at least one type of psychopathology than comparison children. Risk of psychopathology varied across the type of MHP in the target child. Other covariates included sibling age and gender and parental psychopathology. Significant variations and limitations in methodology were found in the existing literature. Methodological guidelines for future studies are outlined. Implications for clinicians, parents, and for future research are discussed.

Necrotizing Enterocolitis Risk

PubMed Central

Gephart, Sheila M.; McGrath, Jacqueline M.; Effken, Judith A.; Halpern, Melissa D.

2012-01-01

Necrotizing enterocolitis (NEC) is the most common cause of gastrointestinal-related morbidity and mortality in the neonatal intensive care unit (NICU). Its onset is sudden and the smallest, most premature infants are the most vulnerable. Necrotizing enterocolitis is a costly disease, accounting for nearly 20% of NICU costs annually. Necrotizing enterocolitis survivors requiring surgery often stay in the NICU more than 90 days and are among those most likely to stay more than 6 months. Significant variations exist in the incidence across regions and units. Although the only consistent independent predictors for NEC remain prematurity and formula feeding, others exist that could increase risk when combined. Awareness of NEC risk factors and adopting practices to reduce NEC risk, including human milk feeding, the use of feeding guidelines, and probiotics, have been shown to reduce the incidence of NEC. The purpose of this review is to examine the state of the science on NEC risk factors and make recommendations for practice and research. PMID:22469959

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

PubMed Central

2012-01-01

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

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

PubMed

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

2012-08-11

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

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

NASA Astrophysics Data System (ADS)

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

2011-12-01

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

[Effects of combined application of nitrogen and phosphorus on diurnal variation of photosynthesis at grain-filling stage and grain yield of super high-yielding wheat].

PubMed

Zhao, Hai-bo; Lin, Qi; Liu, Yi-guo; Jiang, Wen; Liu, Jian-jun; Zhai, Yan-ju

2010-10-01

Taking super high-yielding wheat cultivar Jimai 22 as test material, a field experiment was conducted to study the effects of combined application of nitrogen (N) and phosphorus (P) on the diurnal variation of photosynthesis at grain-filling stage and the grain yield of the cultivar. In treatments CK (without N and P application) and low N/P application (225 kg N x hm(-2) and 75 kg P x hm(-2)), the diurnal variation of net photosynthetic rate (Pn) was presented as double-peak curve, and there existed obvious midday depression of photosynthesis. Under reasonable application of N/P (300 kg N x hm(-2) and 150 kg P x hm(-2), treatment N2P2), the midday depression of photosynthesis weakened or even disappeared. Stomatal and non-stomatal limitations could be the causes of the midday depression. Increasing N and P supply increased the Pn, stomatal conductance (Gs), stomatal limitation value (Ls), and transpiration rate (Tr). Fertilizer P had less effects on the photosynthesis, compared with fertilizer N. When the P supply was over 150 kg x hm(-2), the increment of Pn was alleviated and even decreased. Among the fertilization treatments, treatment N2P2 had the highest Pn, Gs, and water use efficiency, being significantly different from CK. It appeared that fertilizer N had greater regulatory effect on the diurnal variation of photosynthesis, compared with fertilizer P, while the combined application of N and P had significant co-effect on the Pn, Gs, and Tr. A combined application of 300 kg N x hm(-2) and 150 kg P x hm(-2) benefited the enhancement of Pn and grain yield.

International variation in medication prescription rates among elderly patients with inflammatory bowel disease.

PubMed

Benchimol, Eric I; Cook, Suzanne F; Erichsen, Rune; Long, Millie D; Bernstein, Charles N; Wong, Jenna; Carroll, Charlotte F; Frøslev, Trine; Sampson, Tim; Kappelman, Michael D

2013-12-01

The elderly represent a growing demographic of patients with IBD. No study has previously described variations in care or medication prescriptions in senior patients with IBD. We compared prescription rates among elderly patients with IBD in four countries using health administrative data. Databases from the United States (US), United Kingdom (UK), Denmark and Canada were queried. Variation in prescription rates between countries was assessed in patients ≥65y with prevalent IBD who had ≥1 prescription for an IBD-related medication in a given quarter between 2004 and 2009. Patients were identified using previously-reported, validated algorithms. Country-specific rates were compared in each quarter using Fisher's exact test. In patients with Crohn's disease, Canada and US had higher prescription rates for oral 5-ASA (P<0.0001 in all quarters) and infliximab (P<0.05 in 22/24 quarters), while the US had higher rates of thiopurine usage (P<0.05 in 23/24 quarters). Canada had greater rates of methotrexate prescriptions (P<0.05 in 21/24 quarters analyzed). In patients with ulcerative colitis (UC), rates of oral steroid usage was lowest in the US (P<0.05 in 22/24 quarters) and oral 5-ASA use was highest in the US and Canada (P<0.0001 in all quarters). Canada and Denmark used more rectal therapy than the US. Infliximab usage in UC was significantly higher in the US and Canada after 2006. Significant variation in medication prescription rates exists among countries. Future research should assess whether these differences were associated with disparities in outcomes and health care costs. Copyright © 2012 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.

Countergradient variation in locomotor performance of two sympatric Polynesian skinks (Emoia impar, Emoia cyanura).

PubMed

McElroy, Matthew T

2014-01-01

Physiological function in ectotherms is tightly linked to body temperature. As a result, the thermal sensitivity of physiological function may evolve to optimize fitness across different thermal environments. One hypothesis for the evolution of thermal sensitivity, coadaptation, predicts that optimal temperatures for performance should evolve to match the temperatures that an organism experiences in nature. Another hypothesis, countergradient variation, posits that genetic variation can compensate for decreased performance in cool environments, leading to physiological phenotypes that do not track environmental temperatures. On Mo'orea, French Polynesia, thermal ecology and physiology were studied in two morphologically similar skinks that differ in habitat use. Previous studies show that Emoia impar tends to inhabit closed-canopy and interior habitats that are cooler compared to those inhabited by Emoia cyanura, but these differences had not been quantified on Mo'orea. The goal of this study was to determine whether this pattern of habitat partitioning exists on Mo'orea and relates to interspecific differences in thermal physiology and to evaluate whether the evolution of thermal sensitivity supports coadaptation or countergradient variation. I found that E. impar inhabits closed-canopy habitats with cooler substrates and with higher altitudes compared to habitats of E. cyanura. Although the two species do not differ significantly in critical thermal minimum, E. impar has a significantly lower preferred body temperature and critical thermal maximum than does E. cyanura. Despite a preference for cooler habitats and temperatures, E. impar has a warmer optimal temperature for sprint speed and sprints faster than E. cyanura at all temperatures, which supports the countergradient model of thermal adaptation. These results are robust to three different curve-fitting functions and support the view that generalist/specialist trade-offs do not universally constrain the evolution of performance curves.

The existence of parenting styles in the owner-dog relationship.

PubMed

Herwijnen, Ineke R van; van der Borg, Joanne A M; Naguib, Marc; Beerda, Bonne

2018-01-01

Parents interact with children following specific styles, known to influence child development. These styles represent variations in the dimensions of demandingness and responsiveness, resulting in authoritarian, authoritative, permissive or uninvolved parenting. Given the similarities in the parent to child and owner to dog relationships, we determined the extent to which parenting styles exist in the owner to dog relationship using the existing Parenting Styles and Dimensions Questionnaire for the parent-child relationship and an adapted version for dog owners. Items on the parenting of children/dogs were rated for applicability on a five-point Likert scale by 518 Dutch dog owning parents. Principal Component Analyses grouped parenting propensities into styles, with some marked differences between the findings for children and dogs. Dog-directed items grouped into an authoritarian-correction orientated style, incorporating variation in demandingness and focussing on correcting a dog for behaviour verbally/physically, and in two styles based on authoritative items. An authoritative-intrinsic value orientated style reflected variation in mainly responsiveness and oriented on the assumed needs and emotions of the animal. A second authoritative-item based style, captured variations in demandingness and responsiveness. We labelled this style authoritative-training orientated, as it orientated on manners in teaching a dog how to behave in social situations. Thus, we defined dog-directed parenting styles and constructed a Dog-Directed Parenting Styles and Dimensions Questionnaire along the lines of the existing theoretical framework on parenting styles. We did not find a dog-directed parenting style of being permissive or uninvolved, which we attribute to a study population of devoted dog owners and our findings should be interpreted with this specific study population in mind. We found evidence of dog-directed parenting styles and provide a fundament for determining their possible impact on the different aspects of a dog's life.

North–South Asymmetry of the Rotation of the Solar Magnetic Field

NASA Astrophysics Data System (ADS)

Xie, Jinglan; Shi, Xiangjun; Qu, Zhining

2018-03-01

Using the rotation rates of the solar magnetic field during solar cycles 21 to 23 obtained by Chu et al. by analyzing the synoptic magnetic maps produced by the NSO/Kitt Peak and SOHO/MDI during the years 1975 to 2008, the temporal variation of the equatorial rotation rate (A) and the latitude gradient of rotation (B) in the northern and southern hemispheres are studied separately. The results indicate that the rotation is more differential (about 4.3%) in the southern hemisphere in the considered time frame. It is found that the north–south asymmetry of A and the asymmetry of B show increasing trends in the considered time frame, while the north–south asymmetry of the solar activity shows a decreasing trend. There exists a significant negative correlation (at 95% confidence level) between the asymmetry of B and the asymmetry of the solar activity, and this may be due to stronger magnetic activity in a certain hemisphere that may suppress the differential rotation to some extent. The periodicities in the variation of A and B are also studied, and periods of about 5.0 and 10.5 yr (5.5 and 10.4 yr) can be found for the variation of the northern (southern) hemisphere B. Moreover, the north–south asymmetry of A and the asymmetry of B have similar periods of about 2.6–2.7 and 5.2–5.3 yr. Further, cross-correlation analysis indicates that there exists a phase difference (about eight months) between the northern and southern hemisphere B, and this means that the northern hemisphere B generally leads by about eight months.

Interspecific variation in prey capture behavior by co-occurring Nepenthes pitcher plants

PubMed Central

Chin, Lijin; Chung, Arthur YC; Clarke, Charles

2014-01-01

Pitcher plants of the genus Nepenthes capture a wide range of arthropod prey for nutritional benefit, using complex combinations of visual and olfactory signals and gravity-driven pitfall trapping mechanisms. In many localities throughout Southeast Asia, several Nepenthes different species occur in mixed populations. Often, the species present at any given location have strongly divergent trap structures and preliminary surveys indicate that different species trap different combinations of arthropod prey, even when growing at the same locality. On this basis, it has been proposed that co-existing Nepenthes species may be engaged in niche segregation with regards to arthropod prey, avoiding direct competition with congeners by deploying traps that have modifications that enable them to target specific prey types. We examined prey capture among 3 multi-species Nepenthes populations in Borneo, finding that co-existing Nepenthes species do capture different combinations of prey, but that significant interspecific variations in arthropod prey combinations can often be detected only at sub-ordinal taxonomic ranks. In all lowland Nepenthes species examined, the dominant prey taxon is Formicidae, but montane Nepenthes trap few (or no) ants and 2 of the 3 species studied have evolved to target alternative sources of nutrition, such as tree shrew feces. Using similarity and null model analyses, we detected evidence for niche segregation with regards to formicid prey among 5 lowland, sympatric Nepenthes species in Sarawak. However, we were unable to determine whether these results provide support for the niche segregation hypothesis, or whether they simply reflect unquantified variation in heterogeneous habitats and/or ant communities in the study sites. These findings are used to propose improvements to the design of field experiments that seek to test hypotheses about targeted prey capture patterns in Nepenthes. PMID:24481246

Interspecific variation in prey capture behavior by co-occurring Nepenthes pitcher plants: evidence for resource partitioning or sampling-scheme artifacts?

PubMed

Chin, Lijin; Chung, Arthur Y C; Clarke, Charles

2014-01-01

Pitcher plants of the genus Nepenthes capture a wide range of arthropod prey for nutritional benefit, using complex combinations of visual and olfactory signals and gravity-driven pitfall trapping mechanisms. In many localities throughout Southeast Asia, several Nepenthes different species occur in mixed populations. Often, the species present at any given location have strongly divergent trap structures and preliminary surveys indicate that different species trap different combinations of arthropod prey, even when growing at the same locality. On this basis, it has been proposed that co-existing Nepenthes species may be engaged in niche segregation with regards to arthropod prey, avoiding direct competition with congeners by deploying traps that have modifications that enable them to target specific prey types. We examined prey capture among 3 multi-species Nepenthes populations in Borneo, finding that co-existing Nepenthes species do capture different combinations of prey, but that significant interspecific variations in arthropod prey combinations can often be detected only at sub-ordinal taxonomic ranks. In all lowland Nepenthes species examined, the dominant prey taxon is Formicidae, but montane Nepenthes trap few (or no) ants and 2 of the 3 species studied have evolved to target alternative sources of nutrition, such as tree shrew feces. Using similarity and null model analyses, we detected evidence for niche segregation with regards to formicid prey among 5 lowland, sympatric Nepenthes species in Sarawak. However, we were unable to determine whether these results provide support for the niche segregation hypothesis, or whether they simply reflect unquantified variation in heterogeneous habitats and/or ant communities in the study sites. These findings are used to propose improvements to the design of field experiments that seek to test hypotheses about targeted prey capture patterns in Nepenthes.

The notion of snow grain shape: Ambiguous definitions, retrievalfrom tomography and implications on remote sensing

NASA Astrophysics Data System (ADS)

Krol, Q. E.; Loewe, H.

2016-12-01

Grain shape is known to influence the effective physical properties of snow and therefore included in the international classification of seasonal snow. Accordingly, snowpack models account for phenomenological shape parameters (sphericity, dendricity) to capture shape variations. These parameters are however difficult to validate due to the lack of clear-cut definitions from the 3D microstucture and insufficient links to physical properties. While the definition of traditional shape was tailored to the requirements of observers, a more objective definition should be tailored to the requirements of physical properties, by analyzing geometrical (shape) corrections in existing theoretical formulations directly. To this end we revisited the autocorrelation function (ACF) and the chord length distribution (CLD) of snow. Both functions capture size distributions of the microstructure, can be calculated from X-ray tomography and are related to various physical properties. Both functions involve the optical equivalent diameter as dominant quantity, however the respective higher-order geometrical correction differ. We have analyzed these corrections, namely interfacial curvatures for the ACF and the second moment for the CLD, using an existing data set of 165 tomography samples. To unify the notion of shape, we derived various statistical relations between the length scales. Our analysis bears three key practical implications. First, we derived a significantly improved relation between the exponential correlation length and the optical diameter by taking curvatures into account. This adds to the understanding of linking "microwave grain size" and "optical grain size" of snow for remote sensing. Second, we retrieve the optical shape parameter (commonly referred to as B) from tomography images via the moment of the CLD. Third, shape variations seen by observers do not necessarily correspond to shape variations probed by physical properties.

Predicting nitrogen loading with land-cover composition: how can watershed size affect model performance?

PubMed

Zhang, Tao; Yang, Xiaojun

2013-01-01

Watershed-wide land-cover proportions can be used to predict the in-stream non-point source pollutant loadings through regression modeling. However, the model performance can vary greatly across different study sites and among various watersheds. Existing literature has shown that this type of regression modeling tends to perform better for large watersheds than for small ones, and that such a performance variation has been largely linked with different interwatershed landscape heterogeneity levels. The purpose of this study is to further examine the previously mentioned empirical observation based on a set of watersheds in the northern part of Georgia (USA) to explore the underlying causes of the variation in model performance. Through the combined use of the neutral landscape modeling approach and a spatially explicit nutrient loading model, we tested whether the regression model performance variation over the watershed groups ranging in size is due to the different watershed landscape heterogeneity levels. We adopted three neutral landscape modeling criteria that were tied with different similarity levels in watershed landscape properties and used the nutrient loading model to estimate the nitrogen loads for these neutral watersheds. Then we compared the regression model performance for the real and neutral landscape scenarios, respectively. We found that watershed size can affect the regression model performance both directly and indirectly. Along with the indirect effect through interwatershed heterogeneity, watershed size can directly affect the model performance over the watersheds varying in size. We also found that the regression model performance can be more significantly affected by other physiographic properties shaping nitrogen delivery effectiveness than the watershed land-cover heterogeneity. This study contrasts with many existing studies because it goes beyond hypothesis formulation based on empirical observations and into hypothesis testing to explore the fundamental mechanism.

Variation in the prevalence of urinary catheters: a profile of National Health Service patients in England.

PubMed

Shackley, David Clifford; Whytock, Cameron; Parry, Gareth; Clarke, Laurence; Vincent, Charles; Harrison, Abigail; John, Amber; Provost, Lloyd; Power, Maxine

2017-06-23

Harm from catheter-associated urinary tract infections is a common, potentially avoidable, healthcare complication. Variation in catheter prevalence may exist and provide opportunity for reducing harm, yet to date is poorly understood. This study aimed to determine variation in the prevalence of urinary catheters between patient groups, settings, specialities and over time. A prospective study (July 2012 to April 2016) of National Health Service (NHS) patients surveyed by healthcare professionals, following a standardised protocol to determine the presence of a urinary catheter and duration of use, on 1 day per month using the NHS Safety Thermometer. 1314 organisations (253 NHS trusts) and 9 266 284 patients were included. Overall, 12.9% of patients were catheterised, but utilisation varied. There was higher utilisation of catheters in males (15.7% vs 10.7% p<0.001) and younger people (18-70 year 14.0% vs >70 year 12.8% p<0.001), utilisation was highest in hospital settings (18.6% p<0.001), particularly in critical care (76.6% p<0.001). Most catheters had been in situ <28 days (72.9% p<0.001). No clinically significant changes were seen over time in any setting or specialty. Catheter prevalence in patients receiving NHS-funded care varies according to gender, age, setting and specialty, being most prevalent in males, younger people, hospitals and critical care. Utilisation has changed only marginally over 46 months, and further guidance is indicated to provide clarity for clinicians on the insertion and removal of catheters to supplement the existing guidance on care. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Variation in prescription use and spending for lipid-lowering and diabetes medications in the Veterans Affairs Healthcare System.

PubMed

Gellad, Walid F; Good, Chester B; Lowe, John C; Donohue, Julie M

2010-10-01

To examine variation in outpatient prescription use and spending for hyperlipidemia and diabetes mellitus in the Veterans Affairs Healthcare System (VA) and its association with quality measures for these conditions. Cross-sectional. We compared outpatient prescription use, spending, and quality of care across 135 VA medical centers (VAMCs) in fiscal year 2008, including 2.3 million patients dispensed lipid-lowering medications and 981,031 patients dispensed diabetes medications. At each facility, we calculated VAMC-level cost per patient for these medications, the proportion of patients taking brand-name drugs, and Healthcare Effectiveness Data and Information Set (HEDIS) scores for hyperlipidemia (low-density lipoprotein cholesterol level <100 mg/dL) and for diabetes (glycosylated hemoglobin level >9% or not measured). The median cost per patient for lipid-lowering agents in fiscal year 2008 was $49.60 and varied from $39.68 in the least expensive quartile of VAMCs to $69.57 in the most expensive quartile (P < .001). For diabetes agents, the median cost per patient was $158.34 and varied from $123.34 in the least expensive quartile to $198.31 in the most expensive quartile (P < .001). The proportion of patients dispensed brand-name oral drugs among these classes in the most expensive quartile of VAMCs was twice that in the least expensive quartile (P < .001). There was no correlation between VAMC-level prescription spending and performance on HEDIS measures for lipid-lowering drugs (r = 0.12 and r = 0.07) or for diabetes agents (r = -0.10). Despite the existence of a closely managed formulary, significant variation in prescription spending and use of brand-name drugs exists in the VA. Although we could not explicitly risk-adjust, there appears to be no relationship between prescription spending and quality of care.

Working Memory Ability Predicts Trajectories of Early Alcohol Use in Adolescents: The Mediational Role of Impulsivity

PubMed Central

Khurana, Atika; Romer, Dan; Betancourt, Laura M.; Brodsky, Nancy L.; Giannetta, Joan M.; Hurt, Hallam

2012-01-01

Aims 1) To evaluate the role of pre-existing weakness in working memory ability (WM) as a risk factor for early alcohol use as mediated by different forms of impulsivity. 2) To assess the adverse effects of progressive alcohol use on variations in WM over time. Design, Setting and Participants A community sample of 358 adolescents [48% males, Meanage(baseline) = 11.4± 0.87 years] from a longitudinal cohort design, assessed annually over four consecutive years with less than 6% attrition. Measurements Repeated assessments were conducted for the following key variables: WM (based on performance on four separate tasks), frequency of alcohol use (AU), and three forms of impulsivity, namely sensation seeking (SS), acting-without-thinking (AWT) and delay discounting (DD). Latent growth curve modeling procedures were used to identify individual trajectories of change for all key variables. Findings Weakness in WM (at baseline) significantly predicted both concurrent alcohol use and increased frequency of use over the four waves (p <.05). This effect was entirely mediated by two forms of impulsivity, AWT and DD, both of which were characterized by underlying weakness in WM. No individual variation was observed in the slopes of WM, which suggests that individual variations in alcohol use were not associated with changes in WM in our early adolescent sample. Conclusions Early adolescent alcohol use may be a consequence of (pre-existing) weaknesses in working memory (WM) rather than a cause of it. Efforts to reduce early alcohol use should consider the distinct roles of different impulsivity dimensions, in addition to WM, as potential targets of intervention. PMID:23033972

Uranium isotope fractionation induced by aqueous speciation: Implications for U isotopes in marine CaCO3 as a paleoredox proxy

NASA Astrophysics Data System (ADS)

Chen, Xinming; Romaniello, Stephen J.; Anbar, Ariel D.

2017-10-01

Natural variations of 238U/235U in marine CaCO3 rocks are being explored as a novel paleoredox proxy to investigate oceanic anoxia events. Although it is generally assumed that U isotopes in CaCO3 directly record 238U/235U of seawater, recently published laboratory experiments demonstrate slight U isotope fractionation during U(VI) incorporation into abiotic calcium carbonates. This fractionation is hypothesized to depend on aqueous U(VI) speciation, which is controlled by pH, ionic strength, pCO2 and Mg2+ and Ca2+ concentrations. Secular variation in seawater chemistry could lead to changes in aqueous U(VI) speciation, and thus, may affect the extent of U isotope fractionation during U(VI) incorporation into CaCO3. In this study, we combine estimates of seawater composition over the Phanerozoic with a model of aqueous U speciation and isotope fractionation to explore variations in the expected offset between the U isotope composition of seawater and primary marine CaCO3 through time. We find that U isotope fractionation between U in primary marine CaCO3 and seawater could have varied between 0.11 and 0.23‰ over the Phanerozoic due to secular variations in seawater chemistry. Such variations would significantly impact estimates of the extent of marine anoxia derived from the U isotope record. For example, at the Permo-Triassic boundary, this effect might imply that the estimated extent of anoxia is ∼32% more extreme than previously inferred. One significant limitation of our model is that the existing experimental database covers only abiotic carbonate precipitation, and does not include a possible range of biological effects which might enhance or suppress the range of isotopic fractionation calculated here. As biotic carbonates dominate the marine carbonate record, more work is need to assess controls on U isotopic fractionation into biotic marine carbonates.

Microevolutionary dynamics of a macroevolutionary key innovation in a Lepidopteran herbivore

PubMed Central

2010-01-01

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

River water quality assessment using environmentric techniques: case study of Jakara River Basin.

PubMed

Mustapha, Adamu; Aris, Ahmad Zaharin; Juahir, Hafizan; Ramli, Mohammad Firuz; Kura, Nura Umar

2013-08-01

Jakara River Basin has been extensively studied to assess the overall water quality and to identify the major variables responsible for water quality variations in the basin. A total of 27 sampling points were selected in the riverine network of the Upper Jakara River Basin. Water samples were collected in triplicate and analyzed for physicochemical variables. Pearson product-moment correlation analysis was conducted to evaluate the relationship of water quality parameters and revealed a significant relationship between salinity, conductivity with dissolved solids (DS) and 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), and nitrogen in form of ammonia (NH4). Partial correlation analysis (r p) results showed that there is a strong relationship between salinity and turbidity (r p=0.930, p=0.001) and BOD5 and COD (r p=0.839, p=0.001) controlling for the linear effects of conductivity and NH4, respectively. Principal component analysis and or factor analysis was used to investigate the origin of each water quality parameter in the Jakara Basin and identified three major factors explaining 68.11 % of the total variance in water quality. The major variations are related to anthropogenic activities (irrigation agricultural, construction activities, clearing of land, and domestic waste disposal) and natural processes (erosion of river bank and runoff). Discriminant analysis (DA) was applied on the dataset to maximize the similarities between group relative to within-group variance of the parameters. DA provided better results with great discriminatory ability using eight variables (DO, BOD5, COD, SS, NH4, conductivity, salinity, and DS) as the most statistically significantly responsible for surface water quality variation in the area. The present study, however, makes several noteworthy contributions to the existing knowledge on the spatial variations of surface water quality and is believed to serve as a baseline data for further studies. Future research should therefore concentrate on the investigation of temporal variations of water quality in the basin.

Constitutional mechanisms of vulnerability and resilience to nicotine dependence

PubMed Central

Hiroi, N; Scott, D

2017-01-01

The core nature of nicotine dependence is evident in wide variations in how individuals become and remain smokers. Individuals with pre-existing behavioral traits are more likely to develop nicotine dependence and experience difficulty when attempting to quit. Many molecular factors likely contribute to individual variations in the development of nicotine dependence and behavioral traits in complex manners. However, the identification of such molecules has been hampered by the phenotypic complexity of nicotine dependence and the complex ways molecules affect elements of nicotine dependence. We hypothesize that nicotine dependence is, in part, a result of interactions between nicotine and pre-existing behavioral traits. This perspective suggests that the identification of the molecular bases of such pre-existing behavioral traits will contribute to the development of effective methods for reducing smoking dependence and for helping smokers to quit. PMID:19238150

Existence of solution for a general fractional advection-dispersion equation

NASA Astrophysics Data System (ADS)

Torres Ledesma, César E.

2018-05-01

In this work, we consider the existence of solution to the following fractional advection-dispersion equation -d/dt ( p {_{-∞}}It^{β }(u'(t)) + q {t}I_{∞}^{β }(u'(t))) + b(t)u = f(t, u(t)),t\\in R where β \\in (0,1) , _{-∞}It^{β } and tI_{∞}^{β } denote left and right Liouville-Weyl fractional integrals of order β respectively, 0

Killer cell immunoglobulin-like receptor 3DL1 variation modifies HLA-B*57 protection against HIV-1.

PubMed

Martin, Maureen P; Naranbhai, Vivek; Shea, Patrick R; Qi, Ying; Ramsuran, Veron; Vince, Nicolas; Gao, Xiaojiang; Thomas, Rasmi; Brumme, Zabrina L; Carlson, Jonathan M; Wolinsky, Steven M; Goedert, James J; Walker, Bruce D; Segal, Florencia P; Deeks, Steven G; Haas, David W; Migueles, Stephen A; Connors, Mark; Michael, Nelson; Fellay, Jacques; Gostick, Emma; Llewellyn-Lacey, Sian; Price, David A; Lafont, Bernard A; Pymm, Phillip; Saunders, Philippa M; Widjaja, Jacqueline; Wong, Shu Cheng; Vivian, Julian P; Rossjohn, Jamie; Brooks, Andrew G; Carrington, Mary

2018-05-01

HLA-B*57 control of HIV involves enhanced CD8+ T cell responses against infected cells, but extensive heterogeneity exists in the level of HIV control among B*57+ individuals. Using whole-genome sequencing of untreated B*57+ HIV-1-infected controllers and noncontrollers, we identified a single variant (rs643347A/G) encoding an isoleucine-to-valine substitution at position 47 (I47V) of the inhibitory killer cell immunoglobulin-like receptor KIR3DL1 as the only significant modifier of B*57 protection. The association was replicated in an independent cohort and across multiple outcomes. The modifying effect of I47V was confined to B*57:01 and was not observed for the closely related B*57:03. Positions 2, 47, and 54 tracked one another nearly perfectly, and 2 KIR3DL1 allotypes differing only at these 3 positions showed significant differences in binding B*57:01 tetramers, whereas the protective allotype showed lower binding. Thus, variation in an immune NK cell receptor that binds B*57:01 modifies its protection. These data highlight the exquisite specificity of KIR-HLA interactions in human health and disease.

Neonatal extravasation injury: prevention and management in Australia and New Zealand-a survey of current practice

PubMed Central

2013-01-01

Background Extravasation injury remains an important cause of iatrogenic injury in neonatal intensive care. This study aims to describe the current approach to extravasation injury (EI) prevention and management in Neonatal Intensive Care Units (NICUs) in Australia and New Zealand. Methods A literature review regarding extravasation injury in the newborn was carried out to inform questionnaire design. An internet-based survey was then conducted with the clinical directors of the 27 tertiary NICUs in Australia and New Zealand. Results The survey received a 96% response rate. Approximately two thirds of Australian and New Zealand NICUs have written protocols for prevention and management of extravasation injury. Considerable practice variation was seen for both prevention and treatment of EI. 92% of units had experienced cases of significant EI. Conclusions Australian and New Zealand tertiary neonatal units clearly recognise EI as an important cause of iatrogenic morbidity and mortality. Significant variation still exists among units with regards to guidelines for both prevention and management of EI. We recommend that neonatal staff should remain vigilant, ensuring that guidelines for the prevention and treatment of EI are available, and rigorously followed. PMID:23497004

Population, sex and body size: determinants of behavioural variations and behavioural correlations among wild zebrafish Danio rerio.

PubMed

Roy, Tamal; Bhat, Anuradha

2018-01-01

This study (1) investigated variation among populations and the effects of sex and body size on boldness, activity and shoal-association tendency among wild zebrafish, and (2) tested for existence of correlations between behaviours, controlling for sex and body size. Individuals across four natural populations were tested for general activity in a novel situation, number of predator inspections undertaken and tendency to associate with a conspecific shoal in the presence of predators. Results showed a significant effect of population on boldness with a population from high-predation habitat being bolder than populations from low-predation habitats. Males showed significantly higher tendencies than females to associate with a conspecific shoal in the presence of predators. Further, a negative relationship was found between activity and boldness only within two low-predation populations. Individual body size had a strong effect on the activity-boldness relationship within the low-predation population from flowing water habitat. Smaller fish were bolder and less active while larger fish were more cautious and active. Overall, the results indicated that while population-level behavioural responses might be shaped by predation pressure, state-dependent factors could determine behavioural correlations among individuals within populations.

Population, sex and body size: determinants of behavioural variations and behavioural correlations among wild zebrafish Danio rerio

PubMed Central

Roy, Tamal

2018-01-01

This study (1) investigated variation among populations and the effects of sex and body size on boldness, activity and shoal-association tendency among wild zebrafish, and (2) tested for existence of correlations between behaviours, controlling for sex and body size. Individuals across four natural populations were tested for general activity in a novel situation, number of predator inspections undertaken and tendency to associate with a conspecific shoal in the presence of predators. Results showed a significant effect of population on boldness with a population from high-predation habitat being bolder than populations from low-predation habitats. Males showed significantly higher tendencies than females to associate with a conspecific shoal in the presence of predators. Further, a negative relationship was found between activity and boldness only within two low-predation populations. Individual body size had a strong effect on the activity–boldness relationship within the low-predation population from flowing water habitat. Smaller fish were bolder and less active while larger fish were more cautious and active. Overall, the results indicated that while population-level behavioural responses might be shaped by predation pressure, state-dependent factors could determine behavioural correlations among individuals within populations. PMID:29410809

Sedative and analgesic use on night and day shifts in a pediatric cardiovascular intensive care unit.

PubMed

Staveski, Sandra L; Tesoro, Tiffany M; Cisco, Michael J; Roth, Stephen J; Shin, Andrew Y

2014-01-01

The use of sedative and analgesic medications is directly linked to patient outcomes. The practice of administering as-needed sedative or analgesic medications deserves further exploration. We hypothesized that important variations exist in the practice of administering as-needed medications in the intensive care unit (ICU). We aimed to determine the influence of time of day on the practice of administering as-needed sedative or analgesic medications to children in the ICU. Medication administration records of patients admitted to our pediatric cardiovascular ICU during a 4-month period were reviewed to determine the frequency and timing of as-needed medication usage by shift. A total of 152 ICU admissions (1854 patient days) were reviewed. A significantly greater number of as-needed doses were administered during the night shift (fentanyl, P = .005; lorazepam, P = .03; midazolam, P = .0003; diphenhydramine, P = .0003; and chloral hydrate, P = .0006). These differences remained statistically significant after excluding doses given during the first 6 hours after cardiovascular surgery. Morphine administration was similar between shifts (P = .08). We identified a pattern of increased administration of as-needed sedative or analgesic medications during nights. Further research is needed to identify the underlying causes of this practice variation.

Evolutionary heritage influences Amazon tree ecology.

PubMed

Coelho de Souza, Fernanda; Dexter, Kyle G; Phillips, Oliver L; Brienen, Roel J W; Chave, Jerome; Galbraith, David R; Lopez Gonzalez, Gabriela; Monteagudo Mendoza, Abel; Pennington, R Toby; Poorter, Lourens; Alexiades, Miguel; Álvarez-Dávila, Esteban; Andrade, Ana; Aragão, Luis E O C; Araujo-Murakami, Alejandro; Arets, Eric J M M; Aymard C, Gerardo A; Baraloto, Christopher; Barroso, Jorcely G; Bonal, Damien; Boot, Rene G A; Camargo, José L C; Comiskey, James A; Valverde, Fernando Cornejo; de Camargo, Plínio B; Di Fiore, Anthony; Elias, Fernando; Erwin, Terry L; Feldpausch, Ted R; Ferreira, Leandro; Fyllas, Nikolaos M; Gloor, Emanuel; Herault, Bruno; Herrera, Rafael; Higuchi, Niro; Honorio Coronado, Eurídice N; Killeen, Timothy J; Laurance, William F; Laurance, Susan; Lloyd, Jon; Lovejoy, Thomas E; Malhi, Yadvinder; Maracahipes, Leandro; Marimon, Beatriz S; Marimon-Junior, Ben H; Mendoza, Casimiro; Morandi, Paulo; Neill, David A; Vargas, Percy Núñez; Oliveira, Edmar A; Lenza, Eddie; Palacios, Walter A; Peñuela-Mora, Maria C; Pipoly, John J; Pitman, Nigel C A; Prieto, Adriana; Quesada, Carlos A; Ramirez-Angulo, Hirma; Rudas, Agustin; Ruokolainen, Kalle; Salomão, Rafael P; Silveira, Marcos; Stropp, Juliana; Ter Steege, Hans; Thomas-Caesar, Raquel; van der Hout, Peter; van der Heijden, Geertje M F; van der Meer, Peter J; Vasquez, Rodolfo V; Vieira, Simone A; Vilanova, Emilio; Vos, Vincent A; Wang, Ophelia; Young, Kenneth R; Zagt, Roderick J; Baker, Timothy R

2016-12-14

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change. © 2016 The Authors.

Evolutionary heritage influences Amazon tree ecology

PubMed Central

Coelho de Souza, Fernanda; Dexter, Kyle G.; Phillips, Oliver L.; Brienen, Roel J. W.; Chave, Jerome; Galbraith, David R.; Lopez Gonzalez, Gabriela; Monteagudo Mendoza, Abel; Pennington, R. Toby; Poorter, Lourens; Alexiades, Miguel; Álvarez-Dávila, Esteban; Andrade, Ana; Aragão, Luis E. O. C.; Araujo-Murakami, Alejandro; Arets, Eric J. M. M.; Aymard C, Gerardo A.; Baraloto, Christopher; Barroso, Jorcely G.; Bonal, Damien; Boot, Rene G. A.; Camargo, José L. C.; Comiskey, James A.; Valverde, Fernando Cornejo; de Camargo, Plínio B.; Di Fiore, Anthony; Erwin, Terry L.; Feldpausch, Ted R.; Ferreira, Leandro; Fyllas, Nikolaos M.; Gloor, Emanuel; Herault, Bruno; Herrera, Rafael; Higuchi, Niro; Honorio Coronado, Eurídice N.; Killeen, Timothy J.; Laurance, William F.; Laurance, Susan; Lloyd, Jon; Lovejoy, Thomas E.; Malhi, Yadvinder; Maracahipes, Leandro; Marimon, Beatriz S.; Marimon-Junior, Ben H.; Mendoza, Casimiro; Morandi, Paulo; Neill, David A.; Vargas, Percy Núñez; Oliveira, Edmar A.; Lenza, Eddie; Palacios, Walter A.; Peñuela-Mora, Maria C.; Pipoly, John J.; Pitman, Nigel C. A.; Prieto, Adriana; Quesada, Carlos A.; Ramirez-Angulo, Hirma; Rudas, Agustin; Ruokolainen, Kalle; Salomão, Rafael P.; Silveira, Marcos; ter Steege, Hans; Thomas-Caesar, Raquel; van der Hout, Peter; van der Heijden, Geertje M. F.; van der Meer, Peter J.; Vasquez, Rodolfo V.; Vieira, Simone A.; Vilanova, Emilio; Vos, Vincent A.; Wang, Ophelia; Young, Kenneth R.; Zagt, Roderick J.; Baker, Timothy R.

2016-01-01

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change. PMID:27974517

Genetical Analysis of Chromosomal Interaction Effects on the Activities of the Glucose 6-Phosphate and 6-Phosphogluconate Dehydrogenases in DROSOPHILA MELANOGASTER

PubMed Central

Miyashita, Naohiko; Laurie-Ahlberg, C. C.

1984-01-01

By combining ten second and ten third chromosomes, we investigated chromosomal interaction with respect to the action of the modifier factors on G6PD and 6PGD activities in Drosophila melanogaster. Analysis of variance revealed that highly significant chromosomal interaction exists for both enzyme activities. From the estimated variance components, it was concluded that the variation in enzyme activity attributed to the interaction is as great as the variation attributed to the second chromosome but less than attributed to the third chromosome. The interaction is not explained by the variation of body size (live weight). The interaction is generated from both the lack of correlation of second chromosomes for third chromosome backgrounds and the heterogeneous variance of second chromosomes for different third chromosome backgrounds. Large and constant correlation between G6PD and 6PGD activities were found for third chromosomes with any second chromosome background, whereas the correlations for second chromosomes were much smaller and varied considerably with the third chromosome background. This result suggests that the activity modifiers on the second chromosome are under the influence of third chromosome factors. PMID:6425115

Concerted and mosaic evolution of functional modules in songbird brains

PubMed Central

DeVoogd, Timothy J.

2017-01-01

Vertebrate brains differ in overall size, composition and functional capacities, but the evolutionary processes linking these traits are unclear. Two leading models offer opposing views: the concerted model ascribes major dimensions of covariation in brain structures to developmental events, whereas the mosaic model relates divergent structures to functional capabilities. The models are often cast as incompatible, but they must be unified to explain how adaptive changes in brain structure arise from pre-existing architectures and developmental mechanisms. Here we show that variation in the sizes of discrete neural systems in songbirds, a species-rich group exhibiting diverse behavioural and ecological specializations, supports major elements of both models. In accordance with the concerted model, most variation in nucleus volumes is shared across functional domains and allometry is related to developmental sequence. Per the mosaic model, residual variation in nucleus volumes is correlated within functional systems and predicts specific behavioural capabilities. These comparisons indicate that oscine brains evolved primarily as a coordinated whole but also experienced significant, independent modifications to dedicated systems from specific selection pressures. Finally, patterns of covariation between species and brain areas hint at underlying developmental mechanisms. PMID:28490627

Estimating Carcass Persistence and Scavenging Bias in a Human Influenced Landscape

USGS Publications Warehouse

Flint, Paul L.; Lance, Ellen W.; Sowl, Kristine M.; Donnelly, Tyrone F.

2010-01-01

We examined variation in persistence rates of waterfowl carcasses placed along a series of transects in tundra habitats in western Alaska. This study was designed to assess the effects of existing tower structures and was replicated with separate trials in winter, summer and fall as both the resident avian population and the suite of potential scavengers varied seasonally. Carcass persistence rates were uniformly low, with <50% of carcasses persisting for more than a day on average. Persistence rate varied by carcass age, carcass size, among transects and was lowest in the fall and highest in the summer. We found little support for models where persistence varied in relation to the presence of tower structures. We interpret this as evidence that scavengers were not habituated to searching for carcasses near these structures. Our data demonstrate that only a small fraction of bird carcasses are likely to persist between searches, and if not appropriately accounted for, scavenging bias could significantly influence bird mortality estimates. The variation that we documented suggests that persistence rates should not be extrapolated among tower locations or across time periods as the variation in carcass persistence will result in biased estimates of total bird strike mortality.

Natural mode of horizontal transmission of bovine leukemia virus (BLV): the potential role of tabanids (Tabanus spp.).

PubMed

Manet, G; Guilbert, X; Roux, A; Vuillaume, A; Parodi, A L

1989-10-01

In order to evaluate the potential role of hematophagous insects in the natural spreading of bovine leukemia virus (BLV) infection in cattle, a 2-year survey was carried out involving sequential serological tests on 3328 cattle in three different areas. A parallel entomological study was run over the same period, using continuous trapping, in order to determine both the density and variations of horsefly (Tabanus spp.) populations in the close vicinity of the herds. After statistical analysis, this space-time study showed that: (1) There is a significant positive geographical correlation between the rate of incidence of BLV infection and the density of the horsefly population. (2) Seasonal variations in the incidence rate exist; the highest rates are generally observed during summer (from July of September), and the lowest during winter, spring and early summer (from November to mid-July). (3) There is a time link between the rate of sero-conversion and the variations in activity of the horsefly population. All these data combined would appear to indicate that tabanids play a considerable role in the spread of BLV under natural conditions.

Evolving Self-Rated Health in Middle and Old Age: How Does It Differ Across Black, Hispanic, and White Americans?

PubMed Central

Liang, Jersey; Quiñones, Ana R.; Bennett, Joan M.; Ye, Wen; Xu, Xiao; Shaw, Benjamin A.; Ofstedal, Mary Beth

2010-01-01

Objective This research focuses on ethnic variations in the intra-individual changes in self-rated health. Methods Data came from the Health and Retirement Study involving up to 6 repeated observations between 1995 and 2006 of a national sample of 18,486 Americans over 50 years of age. Hierarchical linear models were employed in depicting variations in self-rated health across white, black, and Hispanic Americans. Results Subjective health worsened over time albeit moderately. Relative to younger persons, older individuals rated their health poorer with a greater rate of deteriorating health. With reference to ethnic variations in the intercept and slope of perceived health, white Americans rated their health most positively, followed by black Americans, with Hispanics rating their health least positively. This pattern held even when socioeconomic status, social networks, and prior health were adjusted. Discussion Significant ethnic differences exist in the evolvement of self-rated health in middle and late life. Further inquiries may include analyzing ethnic heterogeneities from a person-centered perspective, health disparities across subgroups of Hispanics, effects of neighborhood attributes, and implications of left truncation. PMID:19952367

Attribution of the Regional Patterns of North American Climate Trends

NASA Astrophysics Data System (ADS)

Hoerling, M.; Kumar, A.; Karoly, D.; Rind, D.; Hegerl, G.; Eischeid, J.

2007-12-01

North American trends in surface temperature and precipitation during 1951-2006 exhibit large spatial and seasonal variations. We seek to explain these by synthesizing new information based on existing model simulations of climate and its forcing, and based on modern reanalyses that describe past and current conditions within the free atmosphere. The presentation focuses on current capabilities to explain the spatial variations and seasonal differences in North American climate trends. It will address whether various heterogeneities in space and time can be accounted for by the climate system's sensitivity to time evolving anthropogenic forcing, and examines the influences of non-anthropogenic processes. New findings are presented that indicate anthropogenic forcing alone was unlikely the cause for key regional and seasonal patterns of change, including the absence of summertime warming over the Great Plains of the United States, and the absence of warming during both winter and summer over the southern United States. Key regional features are instead attributed to trends in the principal patterns of atmospheric flow that affect North American climate. It is demonstrated that observed variations in global sea surface temperatures have significantly influenced these patterns of atmospheric flow.

Significant variations in the cervical cancer screening rate in China by individual-level and geographical measures of socioeconomic status: a multilevel model analysis of a nationally representative survey dataset.

PubMed

Bao, Heling; Zhang, Lei; Wang, Limin; Zhang, Mei; Zhao, Zhenping; Fang, Liwen; Cong, Shu; Zhou, Maigeng; Wang, Linhong

2018-05-01

Variations in cervical cancer screening rates in China have rarely been studied in depth. This study aimed to investigate cervical cancer screening rates in relation to both individual-level and geographical measures of socioeconomic status (SES). Data were obtained from women aged 21 years or older by face-to-face interviews between August 2013 and July 2014 as part of the Chinese Chronic Diseases and Risk Factors Surveillance. The geographical variables were obtained from the 2010 Chinese population census. The cervical cancer screening rates and 95% confidence interval (CI) were estimated and mapped. Multilevel logistic regression models were fitted. Overall, only 21.4% (95% CI: 19.6-23.1%) of 91,816 women aged ≥21 years reported having ever been screened for cervical cancer and significant geographical variations at both province and county levels were identified (P < 0.01). The cervical cancer screening rates were the lowest among the poor [13.9% (95% CI: 12.1-15.7%)], uninsured [14.4% (95% CI: 10.3-18.4%)], less-educated [16.0% (95% CI: 14.3-17.6%)], and agricultural employment [18.1% (95% CI: 15.8-20.4%)] women along with those residing in areas of low economic status [15.0% (95% CI: 11.8-18.2%)], of low urbanization [15.6% (95% CI: 13.4-17.7%)], and of low education status [16.0% (95% CI: 14.0-18.1%)]. The multilevel analysis also indicated that women with lower individual-level measures of SES residing in areas with low geographical measures of SES were significantly less likely to receive cervical cancer screening (P < 0.0001). Despite the launch of an organized cancer screening program in China, cervical cancer screening rates remain alarmingly low and significant variations based on geographical regions and measures of SES still exist. It is therefore essential to adopt strategies to better direct limited available public resources to priority groups. © 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Populations, Natural Selection, and Applied Organizational Science.

ERIC Educational Resources Information Center

McKelvey, Bill; Aldrich, Howard

1983-01-01

Deficiencies in existing models in organizational science may be remedied by applying the population approach, with its concepts of taxonomy, classification, evolution, and population ecology; and natural selection theory, with its principles of variation, natural selection, heredity, and struggle for existence, to the idea of organizational forms…

Revisiting the Holy Grail: using plant functional traits to understand ecological processes.

PubMed

Funk, Jennifer L; Larson, Julie E; Ames, Gregory M; Butterfield, Bradley J; Cavender-Bares, Jeannine; Firn, Jennifer; Laughlin, Daniel C; Sutton-Grier, Ariana E; Williams, Laura; Wright, Justin

2017-05-01

One of ecology's grand challenges is developing general rules to explain and predict highly complex systems. Understanding and predicting ecological processes from species' traits has been considered a 'Holy Grail' in ecology. Plant functional traits are increasingly being used to develop mechanistic models that can predict how ecological communities will respond to abiotic and biotic perturbations and how species will affect ecosystem function and services in a rapidly changing world; however, significant challenges remain. In this review, we highlight recent work and outstanding questions in three areas: (i) selecting relevant traits; (ii) describing intraspecific trait variation and incorporating this variation into models; and (iii) scaling trait data to community- and ecosystem-level processes. Over the past decade, there have been significant advances in the characterization of plant strategies based on traits and trait relationships, and the integration of traits into multivariate indices and models of community and ecosystem function. However, the utility of trait-based approaches in ecology will benefit from efforts that demonstrate how these traits and indices influence organismal, community, and ecosystem processes across vegetation types, which may be achieved through meta-analysis and enhancement of trait databases. Additionally, intraspecific trait variation and species interactions need to be incorporated into predictive models using tools such as Bayesian hierarchical modelling. Finally, existing models linking traits to community and ecosystem processes need to be empirically tested for their applicability to be realized. © 2016 Cambridge Philosophical Society.

Molecular and morphological characterization of the tapeworm Taenia hydatigena (Pallas, 1766) in sheep from Iran.

PubMed

Rostami, S; Salavati, R; Beech, R N; Babaei, Z; Sharbatkhori, M; Baneshi, M R; Hajialilo, E; Shad, H; Harandi, M F

2015-03-01

Although Taenia hydatigena is one of the most prevalent taeniid species of livestock, very little molecular genetic information exists for this parasite. Up to 100 sheep isolates of T. hydatigena were collected from 19 abattoirs located in the provinces of Tehran, Alborz and Kerman. A calibrated microscope was used to measure the larval rostellar hook lengths. Following DNA extraction, fragments of cytochrome c oxidase 1 (CO1) and 12S rRNA genes were amplified by the polymerase chain reaction method and the amplicons were subjected to sequencing. The mean total length of large and small hooks was 203.4 μm and 135.9 μm, respectively. Forty CO1 and 39 12S rRNA sequence haplotypes were obtained in the study. The levels of pairwise nucleotide variation between individual haplotypes of CO1 and 12S rRNA genes were determined to be between 0.3-3.4% and 0.2-2.1%, respectively. The overall nucleotide variation among all the CO1 haplotypes was 9.7%, and for all the 12S rRNA haplotypes it was 10.1%. A significant difference was observed between rostellar hook morphometry and both CO1 and 12S rRNA sequence variability. A significantly high level of genetic variation was observed in the present study. The results showed that the 12S rRNA gene is more variable than CO1.

Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability

PubMed Central

Tang, M.-X.; Mulvana, H.; Gauthier, T.; Lim, A. K. P.; Cosgrove, D. O.; Eckersley, R. J.; Stride, E.

2011-01-01

Ultrasound provides a valuable tool for medical diagnosis offering real-time imaging with excellent spatial resolution and low cost. The advent of microbubble contrast agents has provided the additional ability to obtain essential quantitative information relating to tissue vascularity, tissue perfusion and even endothelial wall function. This technique has shown great promise for diagnosis and monitoring in a wide range of clinical conditions such as cardiovascular diseases and cancer, with considerable potential benefits in terms of patient care. A key challenge of this technique, however, is the existence of significant variations in the imaging results, and the lack of understanding regarding their origin. The aim of this paper is to review the potential sources of variability in the quantification of tissue perfusion based on microbubble contrast-enhanced ultrasound images. These are divided into the following three categories: (i) factors relating to the scanner setting, which include transmission power, transmission focal depth, dynamic range, signal gain and transmission frequency, (ii) factors relating to the patient, which include body physical differences, physiological interaction of body with bubbles, propagation and attenuation through tissue, and tissue motion, and (iii) factors relating to the microbubbles, which include the type of bubbles and their stability, preparation and injection and dosage. It has been shown that the factors in all the three categories can significantly affect the imaging results and contribute to the variations observed. How these factors influence quantitative imaging is explained and possible methods for reducing such variations are discussed. PMID:22866229

A diffusion-matched principal component analysis (DM-PCA) based two-channel denoising procedure for high-resolution diffusion-weighted MRI

PubMed Central

Chang, Hing-Chiu; Bilgin, Ali; Bernstein, Adam; Trouard, Theodore P.

2018-01-01

Over the past several years, significant efforts have been made to improve the spatial resolution of diffusion-weighted imaging (DWI), aiming at better detecting subtle lesions and more reliably resolving white-matter fiber tracts. A major concern with high-resolution DWI is the limited signal-to-noise ratio (SNR), which may significantly offset the advantages of high spatial resolution. Although the SNR of DWI data can be improved by denoising in post-processing, existing denoising procedures may potentially reduce the anatomic resolvability of high-resolution imaging data. Additionally, non-Gaussian noise induced signal bias in low-SNR DWI data may not always be corrected with existing denoising approaches. Here we report an improved denoising procedure, termed diffusion-matched principal component analysis (DM-PCA), which comprises 1) identifying a group of (not necessarily neighboring) voxels that demonstrate very similar magnitude signal variation patterns along the diffusion dimension, 2) correcting low-frequency phase variations in complex-valued DWI data, 3) performing PCA along the diffusion dimension for real- and imaginary-components (in two separate channels) of phase-corrected DWI voxels with matched diffusion properties, 4) suppressing the noisy PCA components in real- and imaginary-components, separately, of phase-corrected DWI data, and 5) combining real- and imaginary-components of denoised DWI data. Our data show that the new two-channel (i.e., for real- and imaginary-components) DM-PCA denoising procedure performs reliably without noticeably compromising anatomic resolvability. Non-Gaussian noise induced signal bias could also be reduced with the new denoising method. The DM-PCA based denoising procedure should prove highly valuable for high-resolution DWI studies in research and clinical uses. PMID:29694400

Complex inner core boundary from frequency characteristics of the reflection coefficients of PKiKP waves observed by Hi-net

NASA Astrophysics Data System (ADS)

Tanaka, Satoru; Tkalčić, Hrvoje

2015-12-01

Frequency-dependent reflection coefficients of P waves at the inner core boundary (ICB) are estimated from the spectral ratios of PKiKP and PcP waves observed by the high-sensitivity seismograph network (Hi-net) in Japan. The corresponding PKiKP reflection locations at the ICB are distributed beneath the western Pacific. At frequencies where noise levels are sufficiently low, spectra of reflection coefficients show four distinct sets of characteristics: a flat spectrum, a spectrum with a significant spectral hole at approximately 1 or 3 Hz, a spectrum with a strong peak at approximately 2 or 3 Hz, and a spectrum containing both a sharp peak and a significant hole. The variety in observed spectra suggests complex lateral variations in ICB properties. To explain the measured differences in frequency characteristics of ICB reflection coefficients, we conduct 2D finite difference simulations of seismic wavefields near the ICB. The models tested in our simulations include a liquid layer and a solid layer above the ICB, as well as sinusoidal and spike-shaped ICB topography with varying heights and scale lengths. We find that the existence of a layer above the ICB can be excluded as a possible explanation for the observed spectra. Furthermore, we find that an ICB topographic model with wavelengths and heights of several kilometers is too extreme to explain our measurements. However, restricting the ICB topography to wavelengths and heights of 1.0-1.5 km can explain the observed frequency-related phenomena. The existence of laterally varying topography may be a sign of lateral variations in inner core solidification.

Applicability of ISSR and DAMD markers for phyto-molecular characterization and association with some important biochemical traits of Dendrobium nobile, an endangered medicinal orchid.

PubMed

Bhattacharyya, Paromik; Kumaria, Suman; Tandon, Pramod

2015-09-01

Dendrobium nobile is an important medicinal orchid having profound importance in traditional herbal drug preparations and pharmacopeias worldwide. Due to various anthropogenic pressures the natural populations of this important orchid species are presently facing threats of extinction. In the present study, genetic and chemical diversity existing amongst 6 natural populations of D. nobile were assessed using molecular markers, and the influence of genetic factors on its phytochemical activity especially antioxidant potential was determined. Molecular fingerprinting of the orchid taxa was performed using ISSR and DAMD markers along with the estimation of total phenolics, flavonoids and alkaloid contents. Antioxidant activity was also measured using DPPH and FRAP assays which cumulatively revealed a significant level of variability across the sampled populations. The representatives from Sikkim in Northeast India revealed higher phytochemical activity whereas those from Mizoram showed lesser activity. Analysis of molecular variance (AMOVA) revealed that variation amongst the populations was significantly higher than within the populations. The data generated by UPGMA and Bayesian analytical models were compared in order to estimate the genetic relationships amongst the D. nobile germplasm sampled from different geographical areas of Northeast India. Interestingly, identical grouping patterns were exhibited by both the approaches. The results of the present study detected a high degree of existing genetic and phytochemical variation amongst the populations in relation to bioclimatic and geographic locations of populations. Our results strongly establish that the cumulative marker approach could be the best suited for assessing the genetic relationships with high accuracy amongst distinct D. nobile accessions. Copyright © 2015 Elsevier Ltd. All rights reserved.

State variation in retail promotions and advertising for Marlboro cigarettes

PubMed Central

Slater, S.; Chaloupka, F.; Wakefield, M.

2001-01-01

BACKGROUND—There is some evidence that tobacco companies marketing efforts undermine the effects of comprehensive tobacco control programmes.
OBJECTIVE—To determine whether point-of-purchase advertising and promotions are more pervasive in states where comprehensive tobacco control programmes are underway.
DESIGN—Cross sectional survey using 1996 data, with merged records of the existence of local tobacco advertising restrictions.
PARTICIPANTS AND SETTING—581 tobacco retail stores located in close proximity to high schools in mainland USA.
MAIN OUTCOME MEASURES—Existence of gift-with-purchase, number of interior advertisements, and exterior store advertisements for Marlboro cigarettes.
RESULTS—After controlling for store type and existence of advertising restrictions, offer of a gift-with-purchase for Marlboro cigarettes was significantly more likely in states with comprehensive tobacco control programmes than those without programmes (odds ratio 2.59, 95% confidence interval 1.57 to 4.26). Although not significant, results show an increase in the number of interior and exterior store advertisements for stores located in states with a comprehensive tobacco control programme than those in other states.
CONCLUSION—Results suggest some point-of-purchase tobacco promotions and advertising are more pervasive in states with comprehensive tobacco control programmes. These efforts are likely to act against the objectives of programmes and need to be accounted for in programme evaluations.


Keywords: advertising; public policy; value added promotions PMID:11740024

Presymplectic current and the inverse problem of the calculus of variations

NASA Astrophysics Data System (ADS)

Khavkine, Igor

2013-11-01

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 variational formulation for a subsystem of the given PDE. No constraints on the differential order or number of dependent or independent variables are assumed. The proof follows a recent observation of Bridges, Hydon, and Lawson [Math. Proc. Cambridge Philos. Soc. 148(01), 159-178 (2010)] and generalizes an older result of Henneaux [Ann. Phys. 140(1), 45-64 (1982)] from ordinary differential equations (ODEs) to PDEs. Uniqueness of the variational formulation is also discussed.

Geo-economic variations in epidemiology, patterns of care, and outcomes in patients with acute respiratory distress syndrome: insights from the LUNG SAFE prospective cohort study.

PubMed

Laffey, John G; Madotto, Fabiana; Bellani, Giacomo; Pham, Tài; Fan, Eddy; Brochard, Laurent; Amin, Pravin; Arabi, Yaseen; Bajwa, Ednan K; Bruhn, Alejandro; Cerny, Vladimir; Clarkson, Kevin; Heunks, Leo; Kurahashi, Kiyoyasu; Laake, Jon Henrik; Lorente, Jose A; McNamee, Lia; Nin, Nicolas; Palo, Jose Emmanuel; Piquilloud, Lise; Qiu, Haibo; Jiménez, Juan Ignacio Silesky; Esteban, Andres; McAuley, Daniel F; van Haren, Frank; Ranieri, Marco; Rubenfeld, Gordon; Wrigge, Hermann; Slutsky, Arthur S; Pesenti, Antonio

2017-08-01

Little information is available about the geo-economic variations in demographics, management, and outcomes of patients with acute respiratory distress syndrome (ARDS). We aimed to characterise the effect of these geo-economic variations in patients enrolled in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE). LUNG SAFE was done during 4 consecutive weeks in winter, 2014, in a convenience sample of 459 intensive-care units in 50 countries across six continents. Inclusion criteria were admission to a participating intensive-care unit (including transfers) within the enrolment window and receipt of invasive or non-invasive ventilation. One of the trial's secondary aims was to characterise variations in the demographics, management, and outcome of patients with ARDS. We used the 2016 World Bank countries classification to define three major geo-economic groupings, namely European high-income countries (Europe-High), high-income countries in the rest of the world (rWORLD-High), and middle-income countries (Middle). We compared patient outcomes across these three groupings. LUNG SAFE is registered with ClinicalTrials.gov, number NCT02010073. Of the 2813 patients enrolled in LUNG SAFE who fulfilled ARDS criteria on day 1 or 2, 1521 (54%) were recruited from Europe-High, 746 (27%) from rWORLD-High, and 546 (19%) from Middle countries. We noted significant geographical variations in demographics, risk factors for ARDS, and comorbid diseases. The proportion of patients with severe ARDS or with ratios of the partial pressure of arterial oxygen (PaO 2 ) to the fractional concentration of oxygen in inspired air (F i O 2 ) less than 150 was significantly lower in rWORLD-High countries than in the two other regions. Use of prone positioning and neuromuscular blockade was significantly more common in Europe-High countries than in the other two regions. Adjusted duration of invasive mechanical ventilation and length of stay in the intensive-care unit were significantly shorter in patients in rWORLD-High countries than in Europe-High or Middle countries. High gross national income per person was associated with increased survival in ARDS; hospital survival was significantly lower in Middle countries than in Europe-High or rWORLD-High countries. Important geo-economic differences exist in the severity, clinician recognition, and management of ARDS, and in patients' outcomes. Income per person and outcomes in ARDS are independently associated. European Society of Intensive Care Medicine, St Michael's Hospital, University of Milan-Bicocca. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microsatellite variation in Donax trunculus from the Iberian Peninsula, with particular attention to Galician estuaries (NW Spain)

NASA Astrophysics Data System (ADS)

Nantón, A.; Arias-Pérez, A.; Freire, R.; Fernández-Pérez, J.; Nóvoa, S.; Méndez, J.

2017-10-01

Genetic variation and population structure information is essential for conservation and stock management policies. The wedge clam Donax trunculus is an important fishing resource in the Iberian Peninsula and in some areas, such as the northwestern Spain, wild stocks have decreased greatly. Despite this, information is mainly from the southwestern Atlantic to the northwestern Mediterranean of the Iberian Peninsula. In this study, fifteen microsatellite loci were examined at 17 localities along the Iberian Peninsula to characterize its genetic diversity and population structure. Particular attention was paid to the northwestern Atlantic area, and to test if the pattern previously described for this species is confirmed when localities distributed across the Atlantic coast are included and different microsatellite markers are used. All localities displayed similar allelic richness values and heterozygosity levels but when genetic diversity levels were compared among groups of localities, tests were significant and samples from the northwestern area (Galicia) showed the lowest values. The analysis of population structure indicated that localities from the Atlantic coast are genetically homogeneous although some samples showed significant pairwise Fst values. These values were low and Bayesian analysis of genetic differentiation did not show a consistent structure along the Atlantic coast of the Iberian Peninsula. However, Atlantic samples were genetically different from those located in Mediterranean coast, which may be explained by the existence of the Almeria-Oran front. Moreover, Fuengirola, locality situated in the Alboran Sea between the Strait of Gibraltar and Mediterranean Sea, showed significant differences from all remaining localities included in the study. Overall, the data showed the existence of genetic homogeneity along the Atlantic coast of the Iberian Peninsula and support the three management units (Atlantic Ocean, the Alboran Sea and the northwestern Mediterranean) previously described in this species. Reduced diversity in the northwestern Spain samples could be related to the exploitation of this resource.

Variaciones polarimétricas en asteroides debidas a rotación

NASA Astrophysics Data System (ADS)

Mesa, V.; Gil-Hutton, R.

The different characteristics of asteroidal surfaces could be studied record- ing the polarimetric variations during a rotational cycle of the object. Since different relations between polarimetric and physical (rugosity, porosity, taxonomy, albedo) parameters exist, it is possible to find information about the physical property responsible of the polarimetric variation. In this pa- per, a study of the polarimetric variations observed on the asteroids (11) Parthenope and (16) Psyche are presented. FULL TEXT IN SPANISH

Psychosocial, Organizational and Cultural Aspects of Terrorism (Aspects Psychosociaux, Organisationnels et Culturels du Terrorisme)

DTIC Science & Technology

2011-11-01

influence by many co- variates and that exists on a continuum of adaptability. To be resilient an individual or society must in the face of a challenge...narratives that carry no credibility [5],[6]. Typically, conspiracy theories consist of variations on the themes of false evidence (e.g., the...migrants are mainly concentrated in the four major big cities of Amsterdam, Rotterdam, Utrecht and The Hague. Although there are variations among the

Standardizing Chinese Sign Language for Use in Post-Secondary Education

ERIC Educational Resources Information Center

Lin, Christina Mien-Chun; Gerner de Garcia, Barbara; Chen-Pichler, Deborah

2009-01-01

There are over 100 languages in China, including Chinese Sign Language. Given the large population and geographical dispersion of the country's deaf community, sign variation is to be expected. Language barriers due to lexical variation may exist for deaf college students in China, who often live outside their home regions. In presenting an…

Population-genomic variation within RNA viruses of the Western honey bee, Apis mellifera, inferred from deep sequencing

USDA-ARS?s Scientific Manuscript database

Deep sequencing of viruses isolated from infected hosts is an efficient way to measure population-genetic variation and can reveal patterns of dispersal and natural selection. In this study, we mined existing Illumina sequence reads to investigate single-nucleotide polymorphisms (SNPs) within two RN...

Short-Term Variations in Response Distribution to Cortical Stimulation

ERIC Educational Resources Information Center

Lesser, Ronald P.; Lee, Hyang Woon; Webber, W. R. S.; Prince, Barry; Crone, Nathan E.; Miglioretti, Diana L.

2008-01-01

Patterns of responses in the cerebral cortex can vary, and are influenced by pre-existing cortical function, but it is not known how rapidly these variations can occur in humans. We investigated how rapidly response patterns to electrical stimulation can vary in intact human brain. We also investigated whether the type of functional change…

General stochastic variational formulation for the oligopolistic market equilibrium problem with excesses

NASA Astrophysics Data System (ADS)

Barbagallo, Annamaria; Di Meglio, Guglielmo; Mauro, Paolo

2017-07-01

The aim of the paper is to study, in a Hilbert space setting, a general random oligopolistic market equilibrium problem in presence of both production and demand excesses and to characterize the random Cournot-Nash equilibrium principle by means of a stochastic variational inequality. Some existence results are presented.

Organizational Training across Cultures: Variations in Practices and Attitudes

ERIC Educational Resources Information Center

Hassi, Abderrahman; Storti, Giovanna

2011-01-01

Purpose: The purpose of this paper is to provide a synthesis based on a review of the existing literature with respect to the variations in training practices and attitudes across national cultures. Design/methodology/approach: A content analysis technique was adopted with a comparative cross-cultural management perspective as a backdrop to…

Intraspecific Variation of Eysarcoris guttigerus (Hemiptera: Pentatomidae) in Japanese Southwest Population Based on Mitochondrial DNA

PubMed Central

Yamaji, Takuya; Ishikawa, Tadashi; Nomura, Masashi

2016-01-01

The white-spotted globular bug Eysarcoris guttigerus (Thunberg) (Hemiptera: Pentatomidae) is widely distributed in East Asia and the Pacific region. In Japan, the species is found in grassy or composite weeds in the western area of the main islands and Ryukyu Islands of Japan. One notable characteristic of the Eysarcoris genus is the two white spots on the scutellum. This is not the case with the Ishigaki Island population, however, which sports red spots instead of white, suggesting that intraspecific variation exists in the species. Therefore, we investigated intraspecific variation in E. guttigerus using mitochondrial NADH dehydrogenase subunit 2 (ND2), cytochrome oxidase subunit 1 (CO1), cytochrome b (Cytb), tRNA-Serine (tRNAser), NADH dehydrogenase subunit 1 (ND1), and 16S ribosomal RNA (16SrRNA) genes from 13 populations of Japan. The obtained maximum likelihood phylogenetic tree was divided into three groups—Group 1: Mainland, Group 2: Central Ryukyu Islands (Okinawa-Amamioshima Islands), and Group 3: South Ryukyu Islands (Ishigaki Island). The Ishigaki population was significantly separated from the other populations with consistent differences in spot color. The estimated period of divergence between the Ishigaki population and the other populations was consistent with the period of formation of the Kerama Gap in the Ryukyu arc. Thus, the process of formation of the Kerama Gap may have influenced the intraspecific variation of E. guttigerus. PMID:26798143

Analysis of temporal variation in human masticatory cycles during gum chewing.

PubMed

Crane, Elizabeth A; Rothman, Edward D; Childers, David; Gerstner, Geoffrey E

2013-10-01

The study investigated modulation of fast and slow opening (FO, SO) and closing (FC, SC) chewing cycle phases using gum-chewing sequences in humans. Twenty-two healthy adult subjects participated by chewing gum for at least 20s on the right side and at least 20s on the left side while jaw movements were tracked with a 3D motion analysis system. Jaw movement data were digitized, and chewing cycle phases were identified and analysed for all chewing cycles in a complete sequence. All four chewing cycle phase durations were more variant than total cycle durations, a result found in other non-human primates. Significant negative correlations existed between the opening phases, SO and FO, and between the closing phases, SC and FC; however, there was less consistency in terms of which phases were negatively correlated both between subjects, and between chewing sides within subjects, compared with results reported in other species. The coordination of intra-cycle phases appears to be flexible and to follow complex rules during gum-chewing in humans. Alternatively, the observed intra-cycle phase relationships could simply reflect: (1) variation in jaw kinematics due to variation in how gum was handled by the tongue on a chew-by-chew basis in our experimental design or (2) by variation due to data sampling noise and/or how phases were defined and identified. Copyright © 2013 Elsevier Ltd. All rights reserved.

Assessment of optical properties variation and discrimination of aerosol and cloud with a multiple-wavelength elastic-Raman lidar in New York City

NASA Astrophysics Data System (ADS)

Arapi, A.; Wu, Y.; Moshary, F.; Blake, R.; Liou-Mark, J.

2017-12-01

Aerosol and cloud play important roles on the Earth's energy budget, which is an important component of climate research. The radiative effects of aerosol-cloud interaction are still highly uncertain and the accuracy of their representation in climate models depends on the accuracy of their measurements. This study evaluates the potential to determine the existence of hydrated aerosols near clouds based on a ground-based multiple-wavelength elastic-Raman lidar at 1064-532-355nm and satellite measurement in New York City area (NYC), east coast of US. The main goal of this study is to examine the variations of color-ratio (spectral or wavelength dependence of backscatter) and relative backscatter to identify patterns between aerosol and cloud. In this presentation, we show the time-height distribution and variation of lidar-measured relative backscatter and color-ratio for some case studies. Then, we employ an aerosol-cloud discrimination algorithm to separate aerosols and clouds according to the color-ratio differences. We demonstrate the significant variation of aerosol optical properties near the low-level clouds in summer, which indicates the potential interaction or transient zone between aerosols and clouds. Finally, we show the preliminary evaluation of the aerosol and cloud product from the satellite retrievals when the ground-lidar observes the transported smoke plumes in NYC area.

Quasivariational Solutions for First Order Quasilinear Equations with Gradient Constraint

NASA Astrophysics Data System (ADS)

Rodrigues, José Francisco; Santos, Lisa

2012-08-01

We prove the existence of solutions for a quasi-variational inequality of evolution with a first order quasilinear operator and a variable convex set which is characterized by a constraint on the absolute value of the gradient that depends on the solution itself. The only required assumption on the nonlinearity of this constraint is its continuity and positivity. The method relies on an appropriate parabolic regularization and suitable a priori estimates. We also obtain the existence of stationary solutions by studying the asymptotic behaviour in time. In the variational case, corresponding to a constraint independent of the solution, we also give uniqueness results.

Geographic and income variations in age at diagnosis and incidence of chronic myeloid leukemia.

PubMed

Mendizabal, Adam M; Younes, Naji; Levine, Paul H

2016-01-01

Developing countries have a younger population of CML patients than developed countries. Patterns of age at diagnosis and incidence by geography and gross national income (GNI) are not well understood. A population-based descriptive study was conducted using data from the International Agency for Research on Cancer's population-based registry compilation. Geographical regions were classified according to the United Nations World Macro Regions and Components. Age-Standardized Incidence Rates (ASR) were adjusted to the World Standard Population. Poisson regression was used to assess age-specific interactions. 57.2% were male among 33,690 diagnoses. Median age at diagnosis was lowest in Africa and Asia (47 years) and highest in Oceania (72 years). ASR was lowest in African males (0.61 per 100,000) and Asian females (0.55 per 100,000) and highest in Oceania males and females (1.78 and 0.96 per 100,000, respectively). A significant interaction (p < 0.0001) between age (<50 years and >50 years) and region exists; no significant differences were seen by region in the <50 age-group while significant differences by region exist in the >50 age group. Population-based estimates suggest that the median age at diagnosis and incidence varies by region. Geographic and income heterogeneity suggest an important effect of environment that warrants further studies.

Habitat fragmentation effects on the orchid bee communities in remnant forests of southeastern Brazil.

PubMed

Knoll, Fátima do Rosário Naschenveng; Penatti, N C

2012-10-01

The effect of habitat fragmentation on the structure of orchid bee communities was analyzed by the investigation of the existence of a spatial structure in the richness and abundance of Euglossini species and by determining the relationship between these data and environmental factors. The surveys were carried out in four different forest fragments and one university campus. Richness, abundance, and diversity of species were analyzed in relation to abiotic (size of the area, extent of the perimeter, perimeter/area ratio, and shape index) and biotic characteristics (vegetation index of the fragment and of the matrix of each of the locations studied). We observed a highly significant positive correlation between the diversity index and the vegetation index of the fragment, landscape and shape index. Our analysis demonstrated that the observed variation could be explained mainly by the vegetation index and the size of the fragment. Variations in relative abundance showed a tendency toward an aggregated spatial distribution between the fragments studied, as well as between the sampling stations within the same habitat, demonstrating the existence of a spatial structure on a small scale in the populations of Euglossini. This distribution will determine the composition of species that coexist in the area after fragmentation. These data help in understanding the differences and similarities in the structure of communities of Euglossini resulting from forest fragmentation.

Variation in Stem Anatomical Characteristics of Campanuloideae Species in Relation to Evolutionary History and Ecological Preferences

PubMed Central

Schweingruber, Fritz Hans; Říha, Pavel; Doležal, Jiří

2014-01-01

Background The detailed knowledge of plant anatomical characters and their variation among closely related taxa is key to understanding their evolution and function. We examined anatomical variation in 46 herbaceous taxa from the subfamily Campanuloideae (Campanulaceae) to link this information with their phylogeny, ecology and comparative material of 56 woody tropical taxa from the subfamily Lobelioideae. The species studied covered major environmental gradients from Mediterranean to Arctic zones, allowing us to test hypotheses on the evolution of anatomical structure in relation to plant competitive ability and ecological preferences. Methodology/Principal Findings To understand the evolution of anatomical diversity, we reconstructed the phylogeny of studied species from nucleotide sequences and examined the distribution of anatomical characters on the resulting phylogenetic tree. Redundancy analysis, with phylogenetic corrections, was used to separate the evolutionary inertia from the adaptation to the environment. A large anatomical diversity exists within the Campanuloideae. Traits connected with the quality of fibres were the most congruent with phylogeny, and the Rapunculus 2 (“phyteumoid”) clade was especially distinguished by a number of characters (absence of fibres, pervasive parenchyma, type of rays) from two other clades (Campanula s. str. and Rapunculus 1) characterized by the dominance of fibres and the absence of parenchyma. Septate fibres are an exclusive trait in the Lobelioideae, separating it clearly from the Campanuloideae where annual rings, pervasive parenchyma and crystals in the phellem are characteristic features. Conclusions/Significance Despite clear phylogenetic inertia in the anatomical features studied, the ecological attributes and plant height had a significant effect on anatomical divergence. From all three evolutionary clades, the taller species converged towards similar anatomical structure, characterized by a smaller number of early wood vessels of large diameter, thinner cell-walls and alternate intervessel pits, while the opposite trend was found in small Arctic and alpine taxa. This supports the existing generalization that narrower vessels allow plants to grow in colder places where they can avoid freezing-induced embolism, while taller plants have wider vessels to minimize hydraulic resistance with their greater path lengths. PMID:24586306

Variation characteristics and influences of climate factors on aridity index and its association with AO and ENSO in northern China from 1961 to 2012

NASA Astrophysics Data System (ADS)

Zhang, Kexin; Qian, Xiaoqing; Liu, Puxing; Xu, Yihong; Cao, Liguo; Hao, Yongpei; Dai, Shengpei

2017-10-01

Analyses of the variation characteristics for aridity index (AI) can further enhance the understanding of climate change and have effect on hydrology and agriculture. In this paper, based on the data of 283 standard meteorological stations, the temporal-spatial variations and the influences of climate factors on AI were investigated and the relationship between AI and two climate indices (the Arctic Oscillation (AO); El Nino-Southern Oscillation (ENSO)) were also assessed in northern China (NC) during the period from 1961 to 2012. The results revealed that the annual mean AI decreased at the rate of -0.031 per decade in the past 52 years and the trend was statistically significant at the 0.01 level. The Mann-Kendall (M-K) test presented that the percentages of stations with positive trends and negative trends for AI were 10 and 81.9 % (22.6 % statistically significant), respectively. Spatially, in the western part of 100° E, the extremely dry area declined and the climate tended to become wet obviously. In the eastern part of 100° E, dry area moved toward the east and the south, which resulted in the enhancement of semiarid area and the shrinkage of subhumid area. The contributions of sunshine duration and precipitation to the decline of AI are more than those of other meteorological variables in NC. Moreover, the average temperature has risen significantly and AI decreased in NC, which indicated the existence of "paradox." Relationship between climate indices (AO and ENSO) and AI demonstrated that the influence of ENSO on AI overweight the AO on AI in NC.

Geographic and Age-Based Variations in Medicare Reimbursement Among ASSH Members.

PubMed

Gaspar, Michael P; Kane, Patrick M; Honik, Grace B; Shin, Eon K; Jacoby, Sidney M; Osterman, A Lee

2016-09-01

Background: The purpose of this study was to investigate how American Society for Surgery of the Hand (ASSH) members' Medicare reimbursement depends on their geographical location and number of years in practice. Methods: Demographic data for surgeons who were active members of the ASSH in 2012 were obtained using information publicly available through the US Centers for Medicare and Medicaid Services (CMS). "Hand-surgeons-per-capita" and average reimbursement per surgeon were calculated for each state. Regression analysis was performed to determine a relationship between (1) each state's average reimbursement versus the number of ASSH members in that state, (2) average reimbursement versus number of hand surgeons per capita, and (3) total reimbursement from Medicare versus number of years in practice. Analysis of variance (ANOVA) was used to detect a difference in reimbursement based on categorical range of years as an ASSH member. Results: A total of 1667 ASSH members satisfied inclusion in this study. Although there was significant variation among states' average reimbursement, reimbursement was not significantly correlated with the state's hand surgeons per capita or total number of hand surgeons in that given state. Correlation between years as an ASSH member and average reimbursement was significant but non-linear; the highest reimbursements were seen in surgeons who had been ASSH members from 8 to 20 years. Conclusions: Peak reimbursement from Medicare for ASSH members appears to be related to the time of surgeons' peak operative volume, rather than any age-based bias for or against treating Medicare beneficiaries. In addition, though geographic variation in reimbursement does exist, this does not appear to correlate with density or availability of hand surgeons.

Fitness prospects: effects of age, sex and recruitment age on reproductive value in a long-lived seabird.

PubMed

Zhang, He; Rebke, Maren; Becker, Peter H; Bouwhuis, Sandra

2015-01-01

Reproductive value is an integrated measure of survival and reproduction fundamental to understanding life-history evolution and population dynamics, but little is known about intraspecific variation in reproductive value and factors explaining such variation, if any. By applying generalized additive mixed models to longitudinal individual-based data of the common tern Sterna hirundo, we estimated age-specific annual survival probability, breeding probability and reproductive performance, based on which we calculated age-specific reproductive values. We investigated effects of sex and recruitment age (RA) on each trait. We found age effects on all traits, with survival and breeding probability declining with age, while reproductive performance first improved with age before levelling off. We only found a very small, marginally significant, sex effect on survival probability, but evidence for decreasing age-specific breeding probability and reproductive performance with RA. As a result, males had slightly lower age-specific reproductive values than females, while birds of both sexes that recruited at the earliest ages of 2 and 3 years (i.e. 54% of the tern population) had somewhat higher fitness prospects than birds recruiting at later ages. While the RA effects on breeding probability and reproductive performance were statistically significant, these effects were not large enough to translate to significant effects on reproductive value. Age-specific reproductive values provided evidence for senescence, which came with fitness costs in a range of 17-21% for the sex-RA groups. Our study suggests that intraspecific variation in reproductive value may exist, but that, in the common tern, the differences are small. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

Concordance between local, institutional, and central pathology review in glioblastoma: implications for research and practice: a pilot study.

PubMed

Gupta, Tejpal; Nair, Vimoj; Epari, Sridhar; Pietsch, Torsten; Jalali, Rakesh

2012-01-01

There is significant inter-observer variation amongst the neuro-pathologists in the typing, subtyping, and grading of glial neoplasms for diagnosis. Centralized pathology review has been proposed to minimize this inter-observer variation and is now almost mandatory for accrual into multicentric trials. We sought to assess the concordance between neuro-pathologists on histopathological diagnosis of glioblastoma. Comparison of local, institutional, and central neuro-oncopathology reporting in a cohort of 34 patients with newly diagnosed supratentorial glioblastoma accrued consecutively at a tertiary-care institution on a prospective trial testing the addition of a new agent to standard chemo-radiation regimen. Concordance was sub-optimal between local histological diagnosis and central review, fair between local diagnosis and institutional review, and good between institutional and central review, with respect to histological typing/subtyping. Twelve (39%) of 31 patients with local histological diagnosis had identical tumor type, subtype and grade on central review. Overall agreement was modestly better (52%) between local diagnosis and institutional review. In contrast, 28 (83%) of 34 patients had completely concordant histopathologic diagnosis between institutional and central review. The inter-observer reliability test showed poor agreement between local and central review (kappa statistic=0.12, 95% confidence interval (CI): -0.03-0.32, P=0.043), but moderate agreement between institutional and central review (kappa statistic=0.51, 95%CI: 0.17-0.84, P=0.00003). Agreement between local diagnosis and institutional review was fair. There exists significant inter-observer variation regarding histopathological diagnosis of glioblastoma with significant implications for clinical research and practice. There is a need for more objective, quantitative, robust, and reproducible criteria for better subtyping for accurate diagnosis.

CLIMATE VARIABILITY, LAND OWNERSHIP AND MIGRATION: EVIDENCE FROM THAILAND ABOUT GENDER IMPACTS

PubMed Central

Curran, Sara R.; Meijer-Irons, Jacqueline

2016-01-01

Scholars point to climate change, often in the form of more frequent and severe drought, as a potential driver of migration in the developing world, particularly for places where populations rely on agriculture for their livelihoods. To date, however, there have been few large-scale, longitudinal studies that explore the relationship between climate change and migration. This study significantly extends current scholarship by evaluating distinctive effects of climatic variation and models these effects on men’s and women’s responsiveness to drought and rainfall. Our study also investigates how land ownership moderates these effects. We find small, but significant, increases in migration above existing migratory levels during periods of prolonged climatic stress, and that these patterns differ both by gender and land tenure. PMID:27547492

Elementary teachers' ideas about, planning for and implementation of learner-directed and teacher-directed inquiry: A mixed methods study

NASA Astrophysics Data System (ADS)

Biggers, Mandy Sue

Using a framework for variations of classroom inquiry (National Research Council [NRC], 2000, p. 29), this study explored 40 inservice elementary teachers' planning, modification, and enactment of kit-based science curriculum materials. As part of the study, a new observation protocol was modified from an existing protocol (Practices of Science Observation Protocol [P-SOP]) to measure the amount of teacher direction in science inquiry lessons (Practices of Science Observation Protocol + Directedness [P-SOPd]). An embedded mixed methods design was employed to investigate four questions: 1. How valid and reliable is the P-SOPd? 2. In what ways do inservice elementary teachers adapt existing elementary science curriculum materials across the inquiry continuum? 3. What is the relationship between the overall quality of inquiry and variations of inquiry in elementary teachers' enacted science instruction? 4. How do inservice elementary teachers' ideas about the inquiry continuum influence their adaptation of elementary science curriculum materials? Each teacher chose three lessons from a science unit for video-recorded observation, and submitted lesson plans for the three lessons. Lesson plans and videos were scored using the P-SOPd. The scores were also compared between the two protocols to determine if a correlation existed between the level of inquiry (measured on the P-SOP) and the amount of teacher direction (measured on the P-SOPd). Findings indicated no significant differences between planned and enacted lessons for the amount of teacher direction, but a correlation existed between the level of inquiry and the amount of teacher direction. In effect, the elementary teachers taught their science curriculum materials with a high level of fidelity for both the features of inquiry and the amount of teacher direction. A smaller group of three case study teachers were followed for the school year to give a more in-depth explanation of the quantitative findings. Case study findings revealed that the teachers' science instruction was teacher-directed while their conceptions of inquiry were student-directed. This study contributes to existing research on preservice teachers' learning about the continuum (Biggers & Forbes, 2012) and inservice teachers' ideas about the five features of inquiry (Biggers & Forbes, in press).

A multiple wavelet coherency method for temporal streamflow-precipitation-temperature relationships in 17 small catchments on the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Yang, Y.; Liu, B.

2017-12-01

Climate change and human activities are two critical factors causing the dramatical variations of streamflow in the Yellow River Basin of China during the last several decades. More and more attention has been paid to the temporal relationships of streamflow with precipitation and temperature recently. The objective of the current study was to explore the contributions of precipitation and temperature to the temporal variations of streamflow on the Loess Plateau using a multiple wavelet coherency method. Annual streamflow during 1961-2013 for 17 small catchments were collected from the Yellow River Conservancy Commission and annual precipitation and temperature for each catchment were derived from the meteorological data at the national weather stations across the Loess Plateau through the China Meteorological Data Sharing Service System. An abrupt decrease was observed in the annual streamflow around year 2000 for any of the 17 catchments investigated, which was believed to be related with the extensive Grain for Green Project. According to bivariate wavelet coherences, however, annual streamflow showed strong temporal variations with annual precipitation at 8 out of the 17 catchments, where the percentage area of significant coherency (PASC) exceeded 50%. Especially in Weihe and Yiluohe catchments, the corresponding PASC were close to 100%, suggesting that annual precipitation change accounted for almost all the temporal streamflow variations. Compared to annual precipitation, the temporal correlation of temperature with streamflow was relatively small, as implied in the lower mean wavelet coherence (MWC) and PASC. Moreover, including temperature in addition to precipitation in the multiple wavelet coherency analysis failed to increase either MWC or PASC in any of the 17 catchments except for Qingjianhe and Qiushuihe catchments. It was indicated that for most catchments on the Loess Plateau, annual temperature was not significantly different from the red noise in explaining the additional variation in streamflow. In view of the small PASC values resulted for most catchments, there existed other environmental and/or anthropogenic factors responsible for the temporal variations of streamflow.

Metagenomic analysis reveals significant changes of microbial compositions and protective functions during drinking water treatment.

PubMed

Chao, Yuanqing; Ma, Liping; Yang, Ying; Ju, Feng; Zhang, Xu-Xiang; Wu, Wei-Min; Zhang, Tong

2013-12-19

The metagenomic approach was applied to characterize variations of microbial structure and functions in raw (RW) and treated water (TW) in a drinking water treatment plant (DWTP) at Pearl River Delta, China. Microbial structure was significantly influenced by the treatment processes, shifting from Gammaproteobacteria and Betaproteobacteria in RW to Alphaproteobacteria in TW. Further functional analysis indicated the basic metabolic functions of microorganisms in TW did not vary considerably. However, protective functions, i.e. glutathione synthesis genes in 'oxidative stress' and 'detoxification' subsystems, significantly increased, revealing the surviving bacteria may have higher chlorine resistance. Similar results were also found in glutathione metabolism pathway, which identified the major reaction for glutathione synthesis and supported more genes for glutathione metabolism existed in TW. This metagenomic study largely enhanced our knowledge about the influences of treatment processes, especially chlorination, on bacterial community structure and protective functions (e.g. glutathione metabolism) in ecosystems of DWTPs.

The Persistence of Subsistence: Wild Food Harvests in Rural Alaska, 1983-2013

NASA Astrophysics Data System (ADS)

Magdanz, J.; Greenberg, J.; Little, J.; Koster, D.

2016-12-01

Many Alaskans depend on family-centered harvests of wild fish, wildlife, and plants in what could be considered a home production model. State and federal laws provide priorities for these "subsistence uses," a divisive political issue in Alaska. We explore Alaska's subsistence economies using community-level demographic, economic, and subsistence harvest estimates from more than 18,000 household surveys administered during 354 projects in 179 Alaska communities from 1983 to 2013. Neither mean subsistence harvests nor mean incomes are significantly associated with time alone. But harvests are associated with time in multiple regression models that explain more than 60% of the variation in mean subsistence harvests per person at the community level. Propensity score matching finds that roads have significant, strong, and negative effects on subsistence harvests, but no significant effects on incomes. Results suggest that - given sustainably managed renewable resources and appropriate levels of exclusion - subsistence economies can co-exist with market economies.

Genetic Diversity of Aromatic Rice Germplasm Revealed By SSR Markers.

PubMed

Jasim Aljumaili, Saba; Rafii, M Y; Latif, M A; Sakimin, Siti Zaharah; Arolu, Ibrahim Wasiu; Miah, Gous

2018-01-01

Aromatic rice cultivars constitute a small but special group of rice and are considered the best in terms of quality and aroma. Aroma is one of the most significant quality traits of rice, and variety with aroma has a higher price in the market. This research was carried out to study the genetic diversity among the 50 aromatic rice accessions from three regions (Peninsular Malaysia, Sabah, and Sarawak) with 3 released varieties as a control using the 32 simple sequence repeat (SSR) markers. The objectives of this research were to quantify the genetic divergence of aromatic rice accessions using SSR markers and to identify the potential accessions for introgression into the existing rice breeding program. Genetic diversity index among the three populations such as Shannon information index ( I ) ranged from 0.25 in control to 0.98 in Sabah population. The mean numbers of effective alleles and Shannon's information index were 0.36 and 64.90%, respectively. Similarly, the allelic diversity was very high with mean expected heterozygosity ( H e ) of 0.60 and mean Nei's gene diversity index of 0.36. The dendrogram based on UPGMA and Nei's genetic distance classified the 53 rice accessions into 10 clusters. Analysis of molecular variance (AMOVA) revealed that 89% of the total variation observed in this germplasm came from within the populations, while 11% of the variation emanated among the populations. These results reflect the high genetic differentiation existing in this aromatic rice germplasm. Using all these criteria and indices, seven accessions (Acc9993, Acc6288, Acc6893, Acc7580, Acc6009, Acc9956, and Acc11816) from three populations have been identified and selected for further evaluation before introgression into the existing breeding program and for future aromatic rice varietal development.

Genetic Diversity of Aromatic Rice Germplasm Revealed By SSR Markers

PubMed Central

Jasim Aljumaili, Saba; Sakimin, Siti Zaharah; Arolu, Ibrahim Wasiu; Miah, Gous

2018-01-01

Aromatic rice cultivars constitute a small but special group of rice and are considered the best in terms of quality and aroma. Aroma is one of the most significant quality traits of rice, and variety with aroma has a higher price in the market. This research was carried out to study the genetic diversity among the 50 aromatic rice accessions from three regions (Peninsular Malaysia, Sabah, and Sarawak) with 3 released varieties as a control using the 32 simple sequence repeat (SSR) markers. The objectives of this research were to quantify the genetic divergence of aromatic rice accessions using SSR markers and to identify the potential accessions for introgression into the existing rice breeding program. Genetic diversity index among the three populations such as Shannon information index (I) ranged from 0.25 in control to 0.98 in Sabah population. The mean numbers of effective alleles and Shannon's information index were 0.36 and 64.90%, respectively. Similarly, the allelic diversity was very high with mean expected heterozygosity (He) of 0.60 and mean Nei's gene diversity index of 0.36. The dendrogram based on UPGMA and Nei's genetic distance classified the 53 rice accessions into 10 clusters. Analysis of molecular variance (AMOVA) revealed that 89% of the total variation observed in this germplasm came from within the populations, while 11% of the variation emanated among the populations. These results reflect the high genetic differentiation existing in this aromatic rice germplasm. Using all these criteria and indices, seven accessions (Acc9993, Acc6288, Acc6893, Acc7580, Acc6009, Acc9956, and Acc11816) from three populations have been identified and selected for further evaluation before introgression into the existing breeding program and for future aromatic rice varietal development. PMID:29736396

Fitness consequences of maternal and embryonic responses to environmental variation: using reptiles as models for studies of developmental plasticity.

PubMed

Warner, Daniel A

2014-11-01

Environmental factors strongly influence phenotypic variation within populations. The environment contributes to this variation in two ways: (1) by acting as a determinant of phenotypic variation (i.e., plastic responses) and (2) as an agent of selection that "chooses" among existing phenotypes. Understanding how these two environmental forces contribute to phenotypic variation is a major goal in the field of evolutionary biology and a primary objective of my research program. The objective of this article is to provide a framework to guide studies of environmental sources of phenotypic variation (specifically, developmental plasticity and maternal effects, and their adaptive significance). Two case studies from my research on reptiles are used to illustrate the general approaches I have taken to address these conceptual topics. Some key points for advancing our understanding of environmental influences on phenotypic variation include (1) merging laboratory-based research that identifies specific environmental effects with field studies to validate ecological relevance; (2) using controlled experimental approaches that mimic complex environments found in nature; (3) integrating data across biological fields (e.g., genetics, morphology, physiology, behavior, and ecology) under an evolutionary framework to provide novel insights into the underlying mechanisms that generate phenotypic variation; (4) assessing fitness consequences using measurements of survival and/or reproductive success across ontogeny (from embryos to adults) and under multiple ecologically-meaningful contexts; and (5) quantifying the strength and form of natural selection in multiple populations over multiple periods of time to understand the spatial and temporal consistency of phenotypic selection. Research programs that focus on organisms that are amenable to these approaches will provide the most promise for advancing our understanding of the environmental factors that generate the remarkable phenotypic diversity observed within populations. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Balancing Selection on a Regulatory Region Exhibiting Ancient Variation That Predates Human–Neandertal Divergence

PubMed Central

Iskow, Rebecca C.; Austermann, Christian; Scharer, Christopher D.; Raj, Towfique; Boss, Jeremy M.; Sunyaev, Shamil; Price, Alkes; Stranger, Barbara; Simon, Viviana; Lee, Charles

2013-01-01

Ancient population structure shaping contemporary genetic variation has been recently appreciated and has important implications regarding our understanding of the structure of modern human genomes. We identified a ∼36-kb DNA segment in the human genome that displays an ancient substructure. The variation at this locus exists primarily as two highly divergent haplogroups. One of these haplogroups (the NE1 haplogroup) aligns with the Neandertal haplotype and contains a 4.6-kb deletion polymorphism in perfect linkage disequilibrium with 12 single nucleotide polymorphisms (SNPs) across diverse populations. The other haplogroup, which does not contain the 4.6-kb deletion, aligns with the chimpanzee haplotype and is likely ancestral. Africans have higher overall pairwise differences with the Neandertal haplotype than Eurasians do for this NE1 locus (p<10−15). Moreover, the nucleotide diversity at this locus is higher in Eurasians than in Africans. These results mimic signatures of recent Neandertal admixture contributing to this locus. However, an in-depth assessment of the variation in this region across multiple populations reveals that African NE1 haplotypes, albeit rare, harbor more sequence variation than NE1 haplotypes found in Europeans, indicating an ancient African origin of this haplogroup and refuting recent Neandertal admixture. Population genetic analyses of the SNPs within each of these haplogroups, along with genome-wide comparisons revealed significant FST (p = 0.00003) and positive Tajima's D (p = 0.00285) statistics, pointing to non-neutral evolution of this locus. The NE1 locus harbors no protein-coding genes, but contains transcribed sequences as well as sequences with putative regulatory function based on bioinformatic predictions and in vitro experiments. We postulate that the variation observed at this locus predates Human–Neandertal divergence and is evolving under balancing selection, especially among European populations. PMID:23593015

The Influence of Weather Variation, Urban Design and Built Environment on Objectively Measured Sedentary Behaviour in Children.

PubMed

Katapally, Tarun Reddy; Rainham, Daniel; Muhajarine, Nazeem

2016-01-01

With emerging evidence indicating that independent of physical activity, sedentary behaviour (SB) can be detrimental to health, researchers are increasingly aiming to understand the influence of multiple contexts such as urban design and built environment on SB. However, weather variation, a factor that continuously interacts with all other environmental variables, has been consistently underexplored. This study investigated the influence of diverse environmental exposures (including weather variation, urban design and built environment) on SB in children. This cross-sectional observational study is part of an active living research initiative set in the Canadian prairie city of Saskatoon. Saskatoon's neighbourhoods were classified based on urban street design into grid-pattern, fractured grid-pattern and curvilinear types of neighbourhoods. Diverse environmental exposures were measured including, neighbourhood built environment, and neighbourhood and household socioeconomic environment. Actical accelerometers were deployed between April and June 2010 (spring-summer) to derive SB of 331 10-14 year old children in 25 one week cycles. Each cycle of accelerometry was conducted on a different cohort of children within the total sample. Accelerometer data were matched with localized weather patterns derived from Environment Canada weather data. Multilevel modeling using Hierarchical Linear and Non-linear Modeling software was conducted by factoring in weather variation to depict the influence of diverse environmental exposures on SB. Both weather variation and urban design played a significant role in SB. After factoring in weather variation, it was observed that children living in grid-pattern neighbourhoods closer to the city centre (with higher diversity of destinations) were less likely to be sedentary. This study demonstrates a methodology that could be replicated to integrate geography-specific weather patterns with existing cross-sectional accelerometry data to understand the influence of urban design and built environment on SB in children.

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

PubMed

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

2015-01-01

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

Development of a model forecasting Dermanyssus gallinae's population dynamics for advancing Integrated Pest Management in laying hen facilities.

PubMed

Mul, Monique F; van Riel, Johan W; Roy, Lise; Zoons, Johan; André, Geert; George, David R; Meerburg, Bastiaan G; Dicke, Marcel; van Mourik, Simon; Groot Koerkamp, Peter W G

2017-10-15

The poultry red mite, Dermanyssus gallinae, is the most significant pest of egg laying hens in many parts of the world. Control of D. gallinae could be greatly improved with advanced Integrated Pest Management (IPM) for D. gallinae in laying hen facilities. The development of a model forecasting the pests' population dynamics in laying hen facilities without and post-treatment will contribute to this advanced IPM and could consequently improve implementation of IPM by farmers. The current work describes the development and demonstration of a model which can follow and forecast the population dynamics of D. gallinae in laying hen facilities given the variation of the population growth of D. gallinae within and between flocks. This high variation could partly be explained by house temperature, flock age, treatment, and hen house. The total population growth variation within and between flocks, however, was in part explained by temporal variation. For a substantial part this variation was unexplained. A dynamic adaptive model (DAP) was consequently developed, as models of this type are able to handle such temporal variations. The developed DAP model can forecast the population dynamics of D. gallinae, requiring only current flock population monitoring data, temperature data and information of the dates of any D. gallinae treatment. Importantly, the DAP model forecasted treatment effects, while compensating for location and time specific interactions, handling the variability of these parameters. The characteristics of this DAP model, and its compatibility with different mite monitoring methods, represent progression from existing approaches for forecasting D. gallinae that could contribute to advancing improved Integrated Pest Management (IPM) for D. gallinae in laying hen facilities. Copyright © 2017 Elsevier B.V. All rights reserved.

Variations in Abdominal Aortic Aneurysm Care: A Report From the International Consortium of Vascular Registries

PubMed Central

Sedrakyan, Art; Mao, Jialin; Venermo, Maarit; Faizer, Rumi; Debus, Sebastian; Behrendt, Christian-Alexander; Scali, Salvatore; Altreuther, Martin; Schermerhorn, Marc; Beiles, Barry; Szeberin, Zoltan; Eldrup, Nikolaj; Danielsson, Gudmundur; Thomson, Ian; Wigger, Pius; Björck, Martin; Cronenwett, Jack L.; Mani, Kevin

2016-01-01

Background: This project by the ICVR (International Consortium of Vascular Registries), a collaboration of 11 vascular surgical quality registries, was designed to evaluate international variation in the contemporary management of abdominal aortic aneurysm (AAA) with relation to recommended treatment guidelines from the Society for Vascular Surgery and the European Society for Vascular Surgery. Methods: Registry data for open and endovascular AAA repair (EVAR) during 2010 to 2013 were collected from 11 countries. Variations in patient selection and treatment were compared across countries and across centers within countries. Results: Among 51 153 patients, 86% were treated for intact AAA (iAAA) and 14% for ruptured AAA. Women constituted 18% of the entire cohort (range, 12% in Switzerland–21% in the United States; P<0.01). Intact AAAs were repaired at diameters smaller than recommended by guidelines in 31% of men (<5.5 cm; range, 6% in Iceland–41% in Germany; P<0.01) and 12% of women with iAAA (<5 cm; range, 0% in Iceland–16% in the United States; P<0.01). Overall, use of EVAR for iAAA varied from 28% in Hungary to 79% in the United States (P<0.01) and for ruptured AAA from 5% in Denmark to 52% in the United States (P<0.01). In addition to the between-country variations, significant variations were present between centers in each country in terms of EVAR use and rate of small AAA repair. Countries that more frequently treated small AAAs tended to use EVAR more frequently (trend: correlation coefficient, 0.51; P=0.14). Octogenarians made up 23% of all patients, ranging from 12% in Hungary to 29% in Australia (P<0.01). In countries with a fee-for-service reimbursement system (Australia, Germany, Switzerland, and the United States), the proportions of small AAA (33%) and octogenarians undergoing iAAA repair (25%) were higher compared with countries with a population-based reimbursement model (small AAA repair, 16%; octogenarians, 18%; P<0.01). In general, center-level variation within countries in the management of AAA was as important as variation between countries. Conclusions: Despite homogeneous guidelines from professional societies, significant variation exists in the management of AAA, most notably for iAAA diameter at repair, use of EVAR, and the treatment of elderly patients. ICVR provides an opportunity to study treatment variation across countries and to encourage optimal practice by sharing these results. PMID:27784712

Mercury content of the Springfield coal, Indiana and Kentucky

USGS Publications Warehouse

Hower, J.C.; Mastalerz, Maria; Drobniak, A.; Quick, J.C.; Eble, C.F.; Zimmerer, M.J.

2005-01-01

With pending regulation of mercury emissions in United States power plants, its control at every step of the combustion process is important. An understanding of the amount of mercury in coal at the mine is the first step in this process. The Springfield coal (Middle Pennsylvanian) is one of the most important coal resources in the Illinois Basin. In Indiana and western Kentucky, Hg contents range from 0.02 to 0.55 ppm. The variation within small areas is comparable to the variation on a basin basis. Considerable variation also exists within the coal column, ranging from 0.04 to 0.224 ppm at one Kentucky site. Larger variations likely exist, since that site does not represent the highest whole-seam Hg nor was the collection of samples done with optimization of trace element variations in mind. Estimates of Hg capture by currently installed pollution control equipment range from 9-53% capture by cold-side electrostatic precipitators (ESP) and 47-81% Hg capture for ESP + flue-gas desulfurization (FGD). The high Cl content of many Illinois basin coals and the installation of Selective Catalytic Reduction of NOx enhances the oxidation of Hg species, improving the ability of ESPs and FGDs to capture Hg. ?? 2005 Elsevier B.V. All rights reserved.

Evaluation of techniques for increasing recall in a dictionary approach to gene and protein name identification.

PubMed

Schuemie, Martijn J; Mons, Barend; Weeber, Marc; Kors, Jan A

2007-06-01

Gene and protein name identification in text requires a dictionary approach to relate synonyms to the same gene or protein, and to link names to external databases. However, existing dictionaries are incomplete. We investigate two complementary methods for automatic generation of a comprehensive dictionary: combination of information from existing gene and protein databases and rule-based generation of spelling variations. Both methods have been reported in literature before, but have hitherto not been combined and evaluated systematically. We combined gene and protein names from several existing databases of four different organisms. The combined dictionaries showed a substantial increase in recall on three different test sets, as compared to any single database. Application of 23 spelling variation rules to the combined dictionaries further increased recall. However, many rules appeared to have no effect and some appear to have a detrimental effect on precision.

THE RECURRENT INTENSITY VARIATIONS OF PRIMARY COSMIC RADIATION IN PERIODS OF MAXIMUM SOLAR ACTIVITY (in French)

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

Freon, A.; Berry, J.; Coste, J.-P.

1959-02-01

Some recordings of the variations of intensity of cosmic neutrons, made since October 1956 at the observatory of the Pic du Midi and since July 1957 on the Kerguelen Islands, have shown the existence, since the beginning of the observations and during at least 20 solar rotations, of a cyclic variation with a stable period equal to 27.35 plus or minus 0.1 solar days and a maximum amplitude of 2.2% attained in October 1957. (tr-auth)

Diversity of abundance patterns of neutron-capture elements in very metal-poor stars

NASA Astrophysics Data System (ADS)

Aoki, Misa; Aoki, Wako; Ishimaru, Yuhri; Wanajo, Shinya

2014-05-01

Observations of Very Metal-Poor stars indicate that there are at least two sites to r-process; "weak r-process" and "main r-process". A question is whether these two are well separated or there exists a variation in the r-process. We present the results of abundance analysis of neutron-capture elements in the two Very Metal-Poor stars HD107752 and HD110184 in the Milky Way halo observed with the Subaru Telescope HDS. The abundance patterns show overabundace at light n-capture elements (e.g. Sr, Y), inferring the element yielding of weak r-process, while heavy neutron-capture elements (e.g. Ba, Eu) are deficient; however, the overabundance of light ones is not as significant as that previously found in stars representing the weak r-process (e.g. HD122563; Honda et al. 2006). Our study show diversity in the abundance patterns from light to heavy neutron-capture elements in VMP stars, suggesting a variation in r-process, which may depend on electron fraction of environment.

Realized heritability of personalities in the great tit (Parus major).

PubMed

Drent, Pieter J; van Oers, Kees; van Noordwijk, Arie J

2003-01-07

Behaviour under conditions of mild stress shows consistent patterns in all vertebrates: exploratory behaviour, boldness, aggressiveness covary in the same way. The existence of highly consistent individual variation in these behavioural strategies, also referred to as personalities or coping styles, allows us to measure the behaviour under standardized conditions on birds bred in captivity, link the standardized measurements to the behaviour under natural conditions and measure natural selection in the field. We have bred the great tit (Parus major), a classical model species for the study of behaviour under natural conditions, in captivity. Here, we report a realized heritability of 54 +/- 5% for early exploratory behaviour, based on four generations of bi-directional artificial selection. In addition to this, we measured hand-reared juveniles and their wild-caught parents in the laboratory. The heritability found in the mid-offspring-mid-parent regression was significantly different from zero. We have thus established the presence of considerable amounts of genetic variation for personality types in a wild bird.

Co-optimizing Generation and Transmission Expansion with Wind Power in Large-Scale Power Grids Implementation in the US Eastern Interconnection

DOE PAGES

You, Shutang; Hadley, Stanton W.; Shankar, Mallikarjun; ...

2016-01-12

This paper studies the generation and transmission expansion co-optimization problem with a high wind power penetration rate in the US Eastern Interconnection (EI) power grid. In this paper, the generation and transmission expansion problem for the EI system is modeled as a mixed-integer programming (MIP) problem. Our paper also analyzed a time series generation method to capture the variation and correlation of both load and wind power across regions. The obtained series can be easily introduced into the expansion planning problem and then solved through existing MIP solvers. Simulation results show that the proposed planning model and series generation methodmore » can improve the expansion result significantly through modeling more detailed information of wind and load variation among regions in the US EI system. Moreover, the improved expansion plan that combines generation and transmission will aid system planners and policy makers to maximize the social welfare in large-scale power grids.« less

How the zebra got its stripes: a problem with too many solutions

PubMed Central

Larison, Brenda; Harrigan, Ryan J.; Thomassen, Henri A.; Rubenstein, Daniel I.; Chan-Golston, Alec M.; Li, Elizabeth; Smith, Thomas B.

2015-01-01

The adaptive significance of zebra stripes has thus far eluded understanding. Many explanations have been suggested, including social cohesion, thermoregulation, predation evasion and avoidance of biting flies. Identifying the associations between phenotypic and environmental factors is essential for testing these hypotheses and substantiating existing experimental evidence. Plains zebra striping pattern varies regionally, from heavy black and white striping over the entire body in some areas to reduced stripe coverage with thinner and lighter stripes in others. We examined how well 29 environmental variables predict the variation in stripe characteristics of plains zebra across their range in Africa. In contrast to recent findings, we found no evidence that striping may have evolved to escape predators or avoid biting flies. Instead, we found that temperature successfully predicts a substantial amount of the stripe pattern variation observed in plains zebra. As this association between striping and temperature may be indicative of multiple biological processes, we suggest that the selective agents driving zebra striping are probably multifarious and complex. PMID:26064590

Modeling Sodium Abundance Variations in the Lunar Crust: A Likely Proxy of Past Solar System History and a Potential Guide to Close-In Rocky Exoplanets

NASA Astrophysics Data System (ADS)

Saxena, P.; Killen, R. M.; Petro, N. E.; Airapetian, V.; Mandell, A.

2017-12-01

While the Moon and Earth are generally similar in terms of composition, there exist variations in the abundance of certain elements among the two bodies. These differences are a likely consequence of differing physical evolution of the two bodies over the solar system's history. We describe how our past and current modeling efforts indicate that a significant fraction of the initial sodium budget of the Moon may have been depleted and transported from the lunar surface since the Moon's formation. Using profiles of sodium abundances from lunar crustal samples may thus serve as a powerful tool towards exploring conditions on the Moon's surface throughout solar system history. Additionally, conditions on the Moon immediately after formation may still be recorded in the lunar crust and may provide a window towards interpreting observations from some of the first rocky exoplanets that will be most amenable to characterization.

Whose IQ is it?--Assessor bias variance in high-stakes psychological assessment.

PubMed

McDermott, Paul A; Watkins, Marley W; Rhoad, Anna M

2014-03-01

Assessor bias variance exists for a psychological measure when some appreciable portion of the score variation that is assumed to reflect examinees' individual differences (i.e., the relevant phenomena in most psychological assessments) instead reflects differences among the examiners who perform the assessment. Ordinary test reliability estimates and standard errors of measurement do not inherently encompass assessor bias variance. This article reports on the application of multilevel linear modeling to examine the presence and extent of assessor bias in the administration of the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) for a sample of 2,783 children evaluated by 448 regional school psychologists for high-stakes special education classification purposes. It was found that nearly all WISC-IV scores conveyed significant and nontrivial amounts of variation that had nothing to do with children's actual individual differences and that the Full Scale IQ and Verbal Comprehension Index scores evidenced quite substantial assessor bias. Implications are explored. 2014 APA

Microsatellite variation reveals weak genetic structure and retention of genetic variability in threatened Chinook salmon (Oncorhynchus tshawytscha) within a Snake River watershed

USGS Publications Warehouse

Neville, Helen; Issacs, Frank B.; Thurow, Russel; Dunham, J.B.; Rieman, B.

2007-01-01

Pacific salmon (Oncorhynchus spp.) have been central to the development of management concepts associated with evolutionarily significant units (ESUs), yet there are still relatively few studies of genetic diversity within threatened and endangered ESUs for salmon or other species. We analyzed genetic variation at 10 microsatellite loci to evaluate spatial population structure and genetic variability in indigenous Chinook salmon (Oncorhynchus tshawytscha) across a large wilderness basin within a Snake River ESU. Despite dramatic 20th century declines in abundance, these populations retained robust levels of genetic variability. No significant genetic bottlenecks were found, although the bottleneck metric (M ratio) was significantly correlated with average population size and variability. Weak but significant genetic structure existed among tributaries despite evidence of high levels of gene flow, with the strongest genetic differentiation mirroring the physical segregation of fish from two sub-basins. Despite the more recent colonization of one sub-basin and differences between sub-basins in the natural level of fragmentation, gene diversity and genetic differentiation were similar between sub-basins. Various factors, such as the (unknown) genetic contribution of precocial males, genetic compensation, lack of hatchery influence, and high levels of current gene flow may have contributed to the persistence of genetic variability in this system in spite of historical declines. This unique study of indigenous Chinook salmon underscores the importance of maintaining natural populations in interconnected and complex habitats to minimize losses of genetic diversity within ESUs.

Demonstration of angular anisotropy in the output of Thematic Mapper

NASA Technical Reports Server (NTRS)

Duggin, M. J. (Principal Investigator); Lindsay, J.; Piwinski, D. J.; Schoch, L. B.

1984-01-01

There is a dependence of TM output (proportional to scene radiance in a manner which will be discussed) upon season, upon cover type and upon view angle. The existence of a significant systematic variation across uniform scenes in p-type (radiometrically and geometrically pre-processed) data is demonstrated. Present pre-processing does remove the effects and the problem must be addressed because the effects are large. While this is in no way attributable to any shortcomings in the thematic mapper, it is an effect which is sufficiently important to warrant more study, with a view to developing suitable pre-processing correction algorithms.

Particle orbits in two-dimensional equilibrium models for the magnetotail

NASA Technical Reports Server (NTRS)

Karimabadi, H.; Pritchett, P. L.; Coroniti, F. V.

1990-01-01

Assuming that there exist an equilibrium state for the magnetotail, particle orbits are investigated in two-dimensional kinetic equilibrium models for the magnetotail. Particle orbits in the equilibrium field are compared with those calculated earlier with one-dimensional models, where the main component of the magnetic field (Bx) was approximated as either a hyperbolic tangent or a linear function of z with the normal field (Bz) assumed to be a constant. It was found that the particle orbits calculated with the two types of models are significantly different, mainly due to the neglect of the variation of Bx with x in the one-dimensional fields.

Vent modification of large ribbon parachutes to enhance cluster performance

NASA Technical Reports Server (NTRS)

Kolega, D. J.; Woodis, W. R.; Reuter, J. D.

1986-01-01

Due to uneven load sharing and lagging inflation rates, the design of the Large Main Parachute (LMP) cluster, used to recover the Space Shuttle steel case Solid Rocket Boosters, had to be modified. The cause of the problem was excessive variation in effective porosity in the crown area of the LMP during first stage inflation. The design modification consisted of adding horizontal ribbons above the existing vent band to reduce the vent porosity and better control the position and attitude of the vent lines. Performance of modified LMP's since introduction indicates that the load sharing between the clustered chutes has been significantly improved.

Stratospheric water vapor feedback

PubMed Central

Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.

2013-01-01

We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric water vapor feedback. We estimate the strength of this feedback in a chemistry–climate model to be +0.3 W/(m2⋅K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause. PMID:24082126

Stepped nozzle

DOEpatents

Sutton, George P.

1998-01-01

An insert which allows a supersonic nozzle of a rocket propulsion system to operate at two or more different nozzle area ratios. This provides an improved vehicle flight performance or increased payload. The insert has significant advantages over existing devices for increasing nozzle area ratios. The insert is temporarily fastened by a simple retaining mechanism to the aft end of the diverging segment of the nozzle and provides for a multi-step variation of nozzle area ratio. When mounted in place, the insert provides the nozzle with a low nozzle area ratio. During flight, the retaining mechanism is released and the insert ejected thereby providing a high nozzle area ratio in the diverging nozzle segment.

BI Crucis - A new symbiotic star

NASA Technical Reports Server (NTRS)

Henize, K. G.; Carlson, E. D.

1980-01-01

A Mount Stromlo spectrogram of BI Cru taken in 1962 shows emission lines of H I, He I, He II, Fe II, N III, and the forbidden O III, forbidden Ne III, and forbidden S II transitions superposed on a weak bluish continuum. A spectrogram by Allen in 1974 shows emission lines of H I and Fe II and possibly weak He I, forbidden Fe II, and forbidden O I lines superposed on an M-star absorption spectrum. The object is evidently a symbiotic star showing large variations in its spectral character. Significant differences exist in the mean ion velocities and appear to be correlated with ionization potential.

Near-infrared line-strengths in elliptical galaxies: evidence for initial mass function variations?

NASA Astrophysics Data System (ADS)

Cenarro, A. J.; Gorgas, J.; Vazdekis, A.; Cardiel, N.; Peletier, R. F.

2003-02-01

We present new relations between recently defined line-strength indices in the near-infrared (CaT*, CaT, PaT, MgI and sTiO) and central velocity dispersion (σ0) for a sample of 35 early-type galaxies, showing evidence for significant anti-correlations between CaII triplet indices (CaT* and CaT) and log σ0. These relations are interpreted in the light of our recent evolutionary synthesis model predictions, suggesting the existence of important Ca underabundances with respect to Fe and/or an increase of the dwarf to giant stars ratio along the mass sequence of elliptical galaxies.

Patterns in root traits of woody species hosting arbuscular and ectomycorrhizas: implications for the evolution of belowground strategies

USDA-ARS?s Scientific Manuscript database

Despite large variation in root traits among species, we have limited understanding of how traits are related to diverse soil resource acquisition strategies. We examined root trait variation among 33 species co-existing in Northeastern US forests that form the two most common mutualisms with mycorr...

Behavioral and Electrophysiological Evidence for the Impact of Regional Variation on Phoneme Perception

ERIC Educational Resources Information Center

Brunelliere, Angele; Dufour, Sophie; Nguyen, Noel; Frauenfelder, Ulrich Hans

2009-01-01

This event-related potential (ERP) study examined the impact of phonological variation resulting from a vowel merger on phoneme perception. The perception of the /e/-/[epsilon]/ contrast which does not exist in Southern French-speaking regions, and which is in the process of merging in Northern French-speaking regions, was compared to the…

On convergence of solutions to variational-hemivariational inequalities

NASA Astrophysics Data System (ADS)

Zeng, Biao; Liu, Zhenhai; Migórski, Stanisław

2018-06-01

In this paper we investigate the convergence behavior of the solutions to the time-dependent variational-hemivariational inequalities with respect to the data. First, we give an existence and uniqueness result for the problem, and then, deliver a continuous dependence result when all the data are subjected to perturbations. A semipermeability problem is given to illustrate our main results.

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

ERIC Educational Resources Information Center

Snyder, William

2001-01-01

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

The Achilles Tendon in Healthy Subjects: An Anthropometric and Ultrasound Mapping Study.

PubMed

Patel, Nick N; Labib, Sameh A

Ultrasonography is an inexpensive, fast, and reliable imaging technique widely used to assess the Achilles tendon. Although significant data exists regarding pathologic tendon changes, ultrasound data from healthy individuals are more limited. We aimed to better characterize ultrasound Achilles tendon measurements in healthy individuals and identify important correlating factors. The information collected included patient demographics, body habitus, activity level, foot dominance, and resting ankle angle. Ultrasound analysis was performed bilaterally on the Achilles tendons of 50 subjects using a high-frequency transducer to measure tendon width, thickness, cross-sectional area, and length. Males had a significantly larger mean tendon length, width, thickness, and cross-sectional area. No statistically significant difference was found in any tendon dimension between the white and black participants. Similarly, no difference was found in any tendon parameter when comparing right versus left leg dominance. Healthy subjects had a mean ankle resting angle of 45.1° ± 24° with no statistically significant difference between right and left ankles. Considering all individuals, each tendon parameter (tendon length, width, thickness, and cross-sectional area) correlated positively with subject height, weight, tibia length, and foot size. Only the Achilles cross-sectional area correlated significantly with the activity level. The resting angle of the ankle correlated positively with both tendon length and thickness. In conclusion, we found significant variations in Achilles tendon anatomy in the healthy adult population. We have thoroughly characterized significant correlations between healthy tendon dimensions and various body habitus, activity levels, and ankle parameters. Greater knowledge of the normal Achilles tendon anatomy and characterization of its variations in the healthy population will potentially allow for better pathologic diagnosis and surgical repair. Copyright © 2017 The American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Determination of the Characteristic Values and Variation Ratio for Sensitive Soils

NASA Astrophysics Data System (ADS)

Milutinovici, Emilia; Mihailescu, Daniel

2017-12-01

In 2008, Romania adopted Eurocode 7, part II, regarding the geotechnical investigations - called SR EN1997-2/2008. However a previous standard already existed in Romania, by using the mathematical statistics in determination of the calculation values, the requirements of Eurocode can be taken into consideration. The setting of characteristics and calculations values of the geotechnical parameters was finally issued in Romania at the end of 2010 at standard NP122-2010 - “Norm regarding determination of the characteristic and calculation values of the geotechnical parameters”. This standard allows using of data already known from analysed area and setting the calculation values of geotechnical parameters. However, this possibility exist, it is not performed easy in Romania, considering that there isn’t any centralized system of information coming from the geotechnical studies performed for various objectives of private or national interests. Every company performing geotechnical studies tries to organize its own data base, but unfortunately none of them use existing centralized data. When determining the values of calculation, an important role is played by the variation ratio of the characteristic values of a geotechnical parameter. There are recommendations in the mentioned Norm, that could be taken into account, regarding the limits of the variation ratio, but these values are mentioned for Quaternary age soils only, normally consolidated, with a content of organic material < 5%. All of the difficult soils are excluded from the Norm even if they exist and affect the construction foundations on more than a half of the Romania’s surface. A type of difficult soil, extremely widespread on the Romania’s territory, is the contractile soil (with high swelling and contractions, very sensitive to the seasonal moisture variations). This type of material covers and influences the construction foundations in one over third of Romania’s territory. This work is proposing to be a step in determination of limits of the variation ratios for the contractile soils category, for the most used geotechnical parameters in the Romanian engineering practice, namely: the index of consistency and the cohesion.

Uncertainty in detecting trend: a new criterion and its applications to global SST

NASA Astrophysics Data System (ADS)

Lian, Tao

2017-10-01

In most parts of the global ocean, the magnitude of the long-term linear trend in sea surface temperature (SST) is much smaller than the amplitude of multi-scale internal variation. One can thus use a specific period in a much longer record to arbitrarily determine the sign of long-term trend, which is statistically significant, in regional SST. This could lead to a controversial conclusion on how global SST responded to the anthropogenic forcing in the recent history. In this study, the uncertainty in the linear trend due to multi-scale internal variation is theoretically investigated. It is found that the "estimated" trend will not change its sign only when its magnitude is greater than a theoretical threshold that scales the influence from the multi-scale internal variation. Otherwise, the sign of the "estimated" trend may depend on the period used. The new criterion is found to be superior over the existing methods when the de-trended time series is dominated by the oscillatory term. Applying this new criterion to a global SST reconstruction from 1881 to 2013 reveals that the influences from multi-scale internal variation on the sign of "estimated" linear trend cannot be excluded in most parts of the Pacific, the southern Indian Ocean and the northern Atlantic; therefore, the warming or/and cooling trends found in these regions cannot be interpreted as the consequences of anthropogenic forcing. It's also suggested that the recent hiatus can be explained by combined uncertainty from internal variations at the interannual and decadal time scales.

Uncertainty in Detecting Trend: A New Criterion and Its Applications to Global SST

NASA Astrophysics Data System (ADS)

Lian, Tao

2017-04-01

In most parts of the global ocean, the magnitude of the long-term linear trend in sea surface temperature (SST) is much smaller than the amplitude of multi-scale internal variation. One can thus use a specific period in a much longer record to arbitrarily determine the sign of long-term trend, which is statistically significant, in regional SST. This could lead to a controversial conclusion on how global SST responded to the anthropogenic forcing in the recent history. In this study, the uncertainty in the linear trend due to multi-scale internal variation is theoretically investigated. It is found that the "estimated" trend will not change its sign only when its magnitude is greater than a theoretical threshold that scales the influence from the multi-scale internal variation. Otherwise, the sign of the "estimated" trend may depend on the period used. The new criterion is found to be superior over the existing methods when the de-trended time series is dominated by the oscillatory term. Applying this new criterion to a global SST reconstruction from 1881 to 2013 reveals that the influences from multi-scale internal variation on the sign of "estimated" linear trend cannot be excluded in most parts of the Pacific, the southern Indian Ocean and the northern Atlantic; therefore, the warming or/and cooling trends found in these regions cannot be interpreted as the consequences of anthropogenic forcing. It's also suggested that the recent hiatus can be explained by combined uncertainty from internal variations at the interannual and decadal time scales.

Decadal Transition of Moisture Sources and Transport in Northwestern China During Summer From 1982 to 2010

NASA Astrophysics Data System (ADS)

Hua, Lijuan; Zhong, Linhao; Ma, Zhuguo

2017-12-01

The northwestern corner of China (NWCC) experienced a decadal transition in summer precipitation during 1982-2010, with a significant upward trend in 1982-2000 (P1) but a downward one in 2001-2010 (P2). A spatially unbounded dynamic recycling model is developed to estimate the moisture sources and moisture transport variations based on ERA-Interim data. The results suggest that more than 88% of NWCC precipitation has external moisture origins in the southwest and northwest terrestrial areas. The increasing precipitation trend during P1 can be explained by the increasing moisture contribution from the southwest and decreasing contribution from the northwest. However, the opposite trends cause the decreasing precipitation trend during P2. In general, the decadal precipitation transition is mainly determined by the variation of short-distance moisture transport from central Asia, although opposite moisture transport variations exist in the Ural Mountains and Northeast Europe. The variation of the precipitation trend is closely associated with a well-organized wave train propagation from the North Atlantic to central Asia. During P1, the wave train structure consists of a titled positive phase North Atlantic Oscillation (NAO), an anticyclonic circulation over Europe, and a cyclonic anomaly over central Asia, which promotes the southwest moisture flux to NWCC. But the opposite circulation pattern dominates P2. The energy dispersion due to the breakdown of the NAO determines the phase and strength of the downstream wave anomalies over Eurasia. This suggests that the summer NAO might influence the decadal variation of NWCC precipitation through the decadal modulation of the Eurasia wave train.

Body proportions in ancient Andeans from high and low altitudes.

PubMed

Weinstein, Karen J

2005-11-01

Living human populations from high altitudes in the Andes exhibit relatively short limbs compared with neighboring groups from lower elevations as adaptations to cold climates characteristic of high-altitude environments. This study compares relative limb lengths and proportions in pre-Contact human skeletons from different altitudes to test whether ecogeographic variation also existed in Andean prehistory. Maximum lengths of the humerus, radius, femur, and tibia, and femoral head breadth are measured in sex-specific groups of adult human skeletons (N = 346) from the central (n = 80) and the south-central (n = 123) Andean coasts, the Atacama Desert at 2,500 m (n = 102), and the southern Peruvian highlands at 2,000-3,800 m (n = 41). To test whether limb lengths vary with altitude, comparisons are made of intralimb proportions, limb lengths against body mass estimates derived from published equations, limb lengths against the geometric mean of all measurements, and principal component analysis. Intralimb proportions do not statistically differ between coastal groups and those from the Atacama Desert, whereas intralimb proportions are significantly shorter in the Peruvian highland sample. Overall body size and limb lengths relative to body size vary along an altitudinal gradient, with larger individuals from coastal environments and smaller individuals with relatively longer limbs for their size from higher elevations. Ecogeographic variation in relation to climate explains the variation in intralimb proportions, and dietary variation may explain the altitudinal cline in body size and limb lengths relative to body size. The potential effects of gene flow on variation in body proportions in Andean prehistory are also explored. Copyright 2005 Wiley-Liss, Inc

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

PubMed Central

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

2012-01-01

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