509 research outputs found

    NASA Ocean Altimeter Pathfinder Project

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    The NOAA/NASA Pathfinder program was created by the Earth Observing System (EOS) Program Office to determine how existing satellite-based data sets can be processed and used to study global change. The data sets are designed to be long time-series data processed with stable calibration and community consensus algorithms to better assist the research community. The Ocean Altimeter Pathfinder Project involves the reprocessing of all altimeter observations with a consistent set of improved algorithms, based on the results from TOPEX/POSEIDON (T/P), into easy-to-use data sets for the oceanographic community for climate research. Details are currently presented in two technical reports: Report# 1: Data Processing Handbook Report #2: Data Set Validation This report describes the validation of the data sets against a global network of high quality tide gauge measurements and provides an estimate of the error budget. The first report describes the processing schemes used to produce the geodetic consistent data set comprised of SEASAT, GEOSAT, ERS-1, TOPEX/ POSEIDON, and ERS-2 satellite observations

    Biphasic Oxidation of Oxy-Hemoglobin in Bloodstains

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    Background: In forensic science, age determination of bloodstains can be crucial in reconstructing crimes. Upon exiting the body, bloodstains transit from bright red to dark brown, which is attributed to oxidation of oxy-hemoglobin (HbO2) to methemoglobin (met-Hb) and hemichrome (HC). The fractions of HbO 2, met-Hb and HC in a bloodstain can be used for age determination of bloodstains. In this study, we further analyze the conversion of HbO2 to met-Hb and HC, and determine the effect of temperature and humidity on the conversion rates. Methodology: The fractions of HbO2, met-Hb and HC in a bloodstain, as determined by quantitative analysis of optical reflectance spectra (450–800 nm), were measured as function of age, temperature and humidity. Additionally, Optical Coherence Tomography around 1300 nm was used to confirm quantitative spectral analysis approach. Conclusions: The oxidation rate of HbO2 in bloodstains is biphasic. At first, the oxidation of HbO2 is rapid, but slows down after a few hours. These oxidation rates are strongly temperature dependent. However, the oxidation of HbO2 seems to be independent of humidity, whereas the transition of met-Hb into HC strongly depends on humidity. Knowledge of these decay rates is indispensable for translating laboratory results into forensic practice, and to enable bloodstain age determination on the crime scene

    The semi-classical expansion and resurgence in gauge theories: new perturbative, instanton, bion, and renormalon effects

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    We study the dynamics of four dimensional gauge theories with adjoint fermions for all gauge groups, both in perturbation theory and non-perturbatively, by using circle compactification with periodic boundary conditions for the fermions. There are new gauge phenomena. We show that, to all orders in perturbation theory, many gauge groups are Higgsed by the gauge holonomy around the circle to a product of both abelian and nonabelian gauge group factors. Non-perturbatively there are monopole-instantons with fermion zero modes and two types of monopole-anti-monopole molecules, called bions. One type are "magnetic bions" which carry net magnetic charge and induce a mass gap for gauge fluctuations. Another type are "neutral bions" which are magnetically neutral, and their understanding requires a generalization of multi-instanton techniques in quantum mechanics - which we refer to as the Bogomolny-Zinn-Justin (BZJ) prescription - to compactified field theory. The BZJ prescription applied to bion-anti-bion topological molecules predicts a singularity on the positive real axis of the Borel plane (i.e., a divergence from summing large orders in peturbation theory) which is of order N times closer to the origin than the leading 4-d BPST instanton-anti-instanton singularity, where N is the rank of the gauge group. The position of the bion--anti-bion singularity is thus qualitatively similar to that of the 4-d IR renormalon singularity, and we conjecture that they are continuously related as the compactification radius is changed. By making use of transseries and Ecalle's resurgence theory we argue that a non-perturbative continuum definition of a class of field theories which admit semi-classical expansions may be possible.Comment: 112 pages, 7 figures; v2: typos corrected, discussion of supersymmetric models added at the end of section 8.1, reference adde

    Seasonal variations in carbon, nitrogen and phosphorus concentrations and C:N:P stoichiometry in different organs of a Larix principis-rupprechtii Mayr. plantation in the Qinling Mountains, China

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    Understanding how concentrations of elements and their stoichiometry change with plant growth and age is critical for predicting plant community responses to environmental change. Weusedlong-term field experiments to explore how the leaf, stem and root carbon (C), nitrogen (N) and phosphorous (P) concentrations and their stoichiometry changed with growth and stand age in a L.principis-rupprechtii Mayr. plantation from 2012–2015 in the Qinling Mountains, China. Our results showed that the C, N and P concentrations and stoichiometric ratios in different tissues of larch stands were affected by stand age, organ type andsampling month and displayed multiple correlations with increased stand age in different growing seasons. Generally, leaf C and N concentrations were greatest in the fast-growing season, but leaf P concentrations were greatest in the early growing season. However, no clear seasonal tendencies in the stem and root C, N and P concentrations were observed with growth. In contrast to N and P, few differences were found in organ-specific C concentrations. Leaf N:P was greatest in the fast-growing season, while C:N and C:P were greatest in the late-growing season. No clear variations were observed in stem and root C:N, C:P andN:Pthroughout the entire growing season, but leaf N:P was less than 14, suggesting that the growth of larch stands was limited by N in our study region. Compared to global plant element concentrations and stoichiometry, the leaves of larch stands had higher C, P, C:NandC:PbutlowerNandN:P,andtherootshadgreater PandC:NbutlowerN,C:Pand N:P. Our study provides baseline information for describing the changes in nutritional elements with plant growth, which will facilitates plantation forest management and restoration, and makes avaluable contribution to the global data pool on leaf nutrition and stoichiometry

    Sustaining a “culture of silence” in the neonatal intensive care unit during nonemergency situations: A grounded theory on ensuring adherence to behavioral modification to reduce noise levels

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    The aim of this study was to generate a substantive theory explaining how the staff in a resource-limited neonatal intensive care unit (NICU) of a developing nation manage to ensure adherence to behavioral modification components of a noise reduction protocol (NsRP) during nonemergency situations. The study was conducted after implementation of an NsRP in a level III NICU of south India. The normal routine of the NICU is highly dynamic because of various categories of staff conducting clinical rounds followed by care-giving activities. This is unpredictably interspersed with very noisy emergency management of neonates who suddenly fall sick. In-depth interviews were conducted with 36 staff members of the NICU (20 staff nurses, six nursing aides, and 10 physicians). Group discussions were conducted with 20 staff nurses and six nursing aides. Data analysis was done in line with the reformulated grounded theory approach, which was based on inductive examination of textual information. The results of the analysis showed that the main concern was to ensure adherence to behavioral modification components of the NsRP. This was addressed by using strategies to “sustain a culture of silence in NICU during nonemergency situations” (core category). The main strategies employed were building awareness momentum, causing awareness percolation, developing a sense of ownership, expansion of caring practices, evolution of adherence, and displaying performance indicators. The “culture of silence” reconditions the existing staff and conditions new staff members joining the NICU. During emergency situations, a “noisy culture” prevailed because of pragmatic neglect of behavioral modification when life support overrode all other concerns. In addition to this, the process of operant conditioning should be formally conducted once every 18 months. The results of this study may be adapted to create similar strategies and establish context specific NsRPs in NICUs with resource constraints

    Motor Properties of Peripersonal Space in Humans

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    Background: A stimulus approaching the body requires fast processing and appropriate motor reactions. In monkeys, fronto-parietal networks are involved both in integrating multisensory information within a limited space surrounding the body (i.e. peripersonal space, PPS) and in action planning and execution, suggesting an overlap between sensory representations of space and motor representations of action. In the present study we investigate whether these overlapping representations also exist in the human brain. Methodology/Principal Findings: We recorded from hand muscles motor-evoked potentials (MEPs) induced by single-pulse of transcranial magnetic stimulation (TMS) after presenting an auditory stimulus either near the hand or in far space. MEPs recorded 50 ms after the near-sound onset were enhanced compared to MEPs evoked after far sounds. This near-far modulation faded at longer inter-stimulus intervals, and reversed completely for MEPs recorded 300 ms after the sound onset. At that time point, higher motor excitability was associated with far sounds. Such auditory modulation of hand motor representation was specific to a hand-centred, and not a body-centred reference frame. Conclusions/Significance: This pattern of corticospinal modulation highlights the relation between space and time in the PPS representation: an early facilitation for near stimuli may reflect immediate motor preparation, whereas, at later time intervals, motor preparation relates to distant stimuli potentially approaching the body

    Thyroid cancer susceptibility polymorphisms: confirmation of loci on chromosomes 9q22 and 14q13, validation of a recessive 8q24 locus and failure to replicate a locus on 5q24

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    Five single nucleotide polymorphisms (SNPs) associated with thyroid cancer (TC) risk have been reported: rs2910164 (5q24); rs6983267 (8q24); rs965513 and rs1867277 (9q22); and rs944289 (14q13). Most of these associations have not been replicated in independent populations and the combined effects of the SNPs on risk have not been examined. This study genotyped the five TC SNPs in 781 patients recruited through the TCUKIN study. Genotype data from 6122 controls were obtained from the CORGI and Wellcome Trust Case-Control Consortium studies. Significant associations were detected between TC and rs965513A (p=6.35×10−34), rs1867277A (p=5.90×10−24), rs944289T (p=6.95×10−7), and rs6983267G (p=0.016). rs6983267 was most strongly associated under a recessive model (PGG vs GT + TT=0.004), in contrast to the association of this SNP with other cancer types. However, no evidence was found of an association between rs2910164 and disease under any risk model (p>0.7). The rs1867277 association remained significant (p=0.008) after accounting for genotypes at the nearby rs965513 (p=2.3×10−13) and these SNPs did not tag a single high risk haplotype. The four validated TC SNPs accounted for a relatively large proportion (∼11%) of the sibling relative risk of TC, principally owing to the large effect size of rs965513 (OR 1.74)

    Fueling the gender gap? Oil and women's labor and marriage market outcomes

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    This paper analyzes the effect of resource-based economic specialization on women's labor market outcomes. Using information on the location and discovery of major oil fields in the Southern United States coupled with a county-level panel derived from US Census data for 1900-1940, we specifically test the hypothesis that the presence of mineral resources can induce changes in the sectoral composition of the local economy that are detrimental to women's labor market outcomes. We find evidence that the discovery of oil at the county level may constitute a substantial male biased demand shock to local labor markets, as it is associated with a higher gender pay gap. However, we find no evidence that oil wealth lowers female labor force participation or has any impact on local marriage and fertility patterns. While our results are consistent with oil shocks limiting female labor market opportunities in some sectors (mainly manufacturing), this effect tends to be compensated by the higher availability of service sector jobs for women who are therefore not driven out of the labor market
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