14,295 research outputs found
An HI View of Galaxy Conformity: HI-rich Environment around HI-excess Galaxies
Using data taken as part of the Bluedisk project we study the connection
between neutral hydrogen (HI) in the environment of spiral galaxies and that in
the galaxies themselves. We measure the total HI mass present in the
environment in a statistical way by studying the distribution of noise peaks in
the HI data cubes obtained for 40 galaxies observed with WSRT. We find that
galaxies whose HI mass fraction is high relative to standard scaling relations
have an excess HI mass in the surrounding environment as well. Gas in the
environment consists of gas clumps which are individually below the detection
limit of our HI data. These clumps may be hosted by small satellite galaxies
and\or be the high-density peaks of a more diffuse gas distribution in the
inter-galactic medium. We interpret this result as an indication for a picture
in which the HI-rich central galaxies accrete gas from an extended gas
reservoir present in their environment.Comment: 15 pages, 13 figures. Accepted for publication in MNRA
BIOMECHANICAL ANALYSIS DURING COUNTERMOVEMENT JUMP IN CHILDREN AND ADULTS
This study was to examine the biomechanical characteristics of children and adults during countermovement jump. Seven children and seven adult males were recruited to the study. A Peak high-speed camera (120Hz) synchronized with a force plate (600Hz) were used to record vertical jumping action. The kinetic parameters were calculated by using inverse dynamic method. Results showed that the children had both immature joint function prior to propulsion and inadequate knee and ankle joints function during propulsion. It is concluded that a lack of form in jumping strategy was performed during vertical jumpings in the children's group in terms of the kinetic methods was performed. This information may be used in following studies about countermovement jump, avoiding some important information needed only by kinematic analysis, it will be more complete to apply kinetic analysis for children movement researches
Genome-Wide Association Study Identifies Loci for Liver Enzyme Concentrations in Mexican Americans: The GUARDIAN Consortium.
ObjectivePopulations of Mexican American ancestry are at an increased risk for nonalcoholic fatty liver disease. The objective of this study was to determine whether loci in known and novel genes were associated with variation in aspartate aminotransferase (AST) (n = 3,644), alanine aminotransferase (ALT) (n = 3,595), and gamma-glutamyl transferase (GGT) (n = 1,577) levels by conducting the first genome-wide association study (GWAS) of liver enzymes, which commonly measure liver function, in individuals of Mexican American ancestry.MethodsLevels of AST, ALT, and GGT were determined by enzymatic colorimetric assays. A multi-cohort GWAS of individuals of Mexican American ancestry was performed. Single-nucleotide polymorphisms (SNP) were tested for association with liver outcomes by multivariable linear regression using an additive genetic model. Association analyses were conducted separately in each cohort, followed by a nonparametric meta-analysis.ResultsIn the PNPLA3 gene, rs4823173 (P = 3.44 × 10-10 ), rs2896019 (P = 7.29 × 10-9 ), and rs2281135 (P = 8.73 × 10-9 ) were significantly associated with AST levels. Although not genome-wide significant, these same SNPs were the top hits for ALT (P = 7.12 × 10-8 , P = 1.98 × 10-7 , and P = 1.81 × 10-7 , respectively). The strong correlation (r2  = 1.0) for these SNPs indicated a single hit in the PNPLA3 gene. No genome-wide significant associations were found for GGT.ConclusionsPNPLA3, a locus previously identified with ALT, AST, and nonalcoholic fatty liver disease in European and Japanese GWAS, is also associated with liver enzymes in populations of Mexican American ancestry
Multiphoton detachment of electrons from negative ions
A simple analytical solution for the problem of multiphoton detachment from
negative ions by a linearly polarized laser field is found. It is valid in the
wide range of intensities and frequencies of the field, from the perturbation
theory to the tunneling regime, and is applicable to the excess-photon as well
as near-threshold detachment. Practically, the formulae are valid when the
number of photons is greater than two. They produce the total detachment rates,
relative intensities of the excess-photon peaks, and photoelectron angular
distributions for the hydrogen and halogen negative ions, in agreement with
those obtained in other, more numerically involved calculations in both
perturbative and non-perturbative regimes. Our approach explains the extreme
sensitivity of the multiphoton detachment probability to the asymptotic
behaviour of the bound-state wave function. Rapid oscillations in the angular
dependence of the -photon detachment probability are shown to arise due to
interference of the two classical trajectories which lead to the same final
state after the electron emerges at the opposite sides of the atom when the
field is close to maximal.Comment: 27 pages, Latex, and PostScript figures fig1.ps, fig2.ps, fig3.ps,
accepted for publication in Phys. Rev.
Glutathione-triggered disassembly of isothermally responsive polymer nanoparticles obtained by nanoprecipitation of hydrophilic polymers
The encapsulation and selective delivery of therapeutic compounds within polymeric nanoparticles offers hope for the treatment of a variety of diseases. Traditional approaches to trigger selective cargo release typically rely on polymer degradation which is not always sensitive to the biological location of a material. In this report, we prepare nanoparticles from thermoresponsive polymers with a ‘solubility release catch’ at the chain-end. This release catch is exclusively activated in the presence of intracellular glutathione, triggering an ‘isothermal’ response and promoting a change in polymer solubility. This solubility switch leads to specific and rapid nanoparticle disassembly, release of encapsulated cargo and produces completely soluble polymeric side-products
Changes in peripheral immune cell numbers and functions in octogenarian walkers - an acute exercise study.
BACKGROUND: Age-related changes of the immune system, termed immunosenescence, may underlie the increased risk of infections and morbidity in the elderly. Little is known about the effects of acute exercise on peripheral immune parameters in octogenarians. Therefore, we investigated acute exercise-induced changes in phenotype and function of the immune system in octogenarians participating in the 2013 edition of the Nijmegen Four Days Marches. Blood sampling was performed at baseline and immediately after 4 days of the walking exercise (30 km/day). A comprehensive set of adaptive and innate immune traits were enumerated and analyzed by flow-cytometry. Peripheral blood mononuclear cells, isolated before and after walking were stimulated with LPS and supernatants were analysed for IL-1β, IL-6, IL-8 and TNF-α concentrations by ELISA. CMV serostatus was determined by ELISA. RESULTS: The walking exercise induced a clear leucocytosis with numerical increases of granulocytes, monocytes and lymphocytes. These exercise-induced changes were most profound in CMV seropositive subjects. Within lymphocytes, numerical increases of particularly CD4+ T cells were noted. Further T cell differentiation analysis revealed profound increases of naïve CD4+ T cells, including naïve Treg. Significant increases were also noted for CD4+ memory T cell subsets. In contrast, only slight increases in naïve and memory CD8+ T cell subsets were detected. Exercise did not affect markers of immune exhaustion in memory T cell subsets. NK cells demonstrated a numerical decline and a change in cellular composition with a selective decrease of the mature CD56(dim) NK cells. The latter was seen in CMV seronegative subjects only. Also, a higher IL-6 and IL-8 production capacity of LPS-stimulated PBMC was seen after walking. CONCLUSION: In this exceptional cohort of octogenarian walkers, acute exercise induced changes in immune cell numbers and functions. A clear response of CD4+ T cells, rather than CD8+ T cells or NK cells was noted. Remarkably, the response to exercise within the CD4+ T cell compartment was dominated by naïve CD4+ subsets
Super duality and irreducible characters of ortho-symplectic Lie superalgebras
We formulate and establish a super duality which connects parabolic
categories between the ortho-symplectic Lie superalgebras and classical Lie
algebras of types. This provides a complete and conceptual solution of
the irreducible character problem for the ortho-symplectic Lie superalgebras in
a parabolic category , which includes all finite-dimensional irreducible
modules, in terms of classical Kazhdan-Lusztig polynomials.Comment: 30 pages, Section 5 rewritten and shortene
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