4,872 research outputs found
(Anti)symmetric multivariate trigonometric functions and corresponding Fourier transforms
Four families of special functions, depending on n variables, are studied. We
call them symmetric and antisymmetric multivariate sine and cosine functions.
They are given as determinants or antideterminants of matrices, whose matrix
elements are sine or cosine functions of one variable each. These functions are
eigenfunctions of the Laplace operator, satisfying specific conditions at the
boundary of a certain domain F of the n-dimensional Euclidean space. Discrete
and continuous orthogonality on F of the functions within each family, allows
one to introduce symmetrized and antisymmetrized multivariate Fourier-like
transforms, involving the symmetric and antisymmetric multivariate sine and
cosine functions.Comment: 25 pages, no figures; LaTaX; corrected typo
Postgerminative growth and lipid catabolism in oilseeds lacking the glyoxylate cycle
The glyoxylate cycle is regarded as essential for postgerminative growth and seedling establishment in oilseed plants. We have identified two allelic Arabidopsis mutants, icl-1 and icl-2, which lack the glyoxylate cycle because of the absence of the key enzyme isocitrate lyase. These mutants demonstrate that the glyoxylate cycle is not essential for germination. Furthermore, photosynthesis can compensate for the absence of the glyoxylate cycle during postgerminative growth, and only when light intensity or day length is decreased does seedling establishment become compromised. The provision of exogenous sugars can overcome this growth deficiency. The icl mutants also demonstrate that the glyoxylate cycle is important for seedling survival and recovery after prolonged dark conditions that approximate growth in nature. Surprisingly, despite their inability to catalyze the net conversion of acetate to carbohydrate, mutant seedlings are able to break down storage lipids. Results suggest that lipids can be used as a source of carbon for respiration in germinating oilseeds and that products of fatty acid catabolism can pass from the peroxisome to the mitochondrion independently of the glyoxylate cycle. However, an additional anaplerotic source of carbon is required for lipid breakdown and seedling establishment. This source can be provided by the glyoxylate cycle or, in its absence, by exogenous sucrose or photosynthesis
Low-latency analysis pipeline for compact binary coalescences in the advanced gravitational wave detector era
The multi-band template analysis (MBTA) pipeline is a low-latency coincident
analysis pipeline for the detection of gravitational waves (GWs) from compact
binary coalescences. MBTA runs with a low computational cost, and can identify
candidate GW events online with a sub-minute latency. The low computational
running cost of MBTA also makes it useful for data quality studies. Events
detected by MBTA online can be used to alert astronomical partners for
electromagnetic follow-up. We outline the current status of MBTA and give
details of recent pipeline upgrades and validation tests that were performed in
preparation for the first advanced detector observing period. The MBTA pipeline
is ready for the outset of the advanced detector era and the exciting prospects
it will bring.Comment: 18 pages, 10 figure
Does Landowner Awareness and Knowledge Lead to Sustainable Forest Management? A Vermont Case Study
Family forest owners control 40% of forestland in the United States. Timber harvesting on family forests represents a critical component of the nation\u27s wood supply. We examined how awareness and knowledge translated into actual forest management practices. We conducted field surveys on 59 family forest properties, coupled with a landowner survey designed to measure landowner engagement. We determined that engaged landowners implemented silviculture and Best Management Practices at a higher level than their less engaged counterparts. Improvement was needed across the board. Forestry Extension professionals should continue to promote and re-enforce awareness and knowledge among landowners
Mutation of tyrosine 492/493 in the kinase domain of ZAP-70 affects multiple T-cell receptor signaling pathways.
The protein-tyrosine kinase ZAP-70 is implicated, together with the Src kinase p56lck, in controlling the early steps of the T-cell antigen receptor (TCR) signaling cascade. To help elucidate further the mechanism by which ZAP-70 regulates these initial events, we used a dominant-negative mutant approach. We overexpressed in the Jurkat T-cell line ZAP-70 mutated on Tyr-492 and Tyr-493 in the putative regulatory loop of its kinase domain. This mutant inhibited TCR-induced activation of nuclear factor of activated T cells by interfering with both intracellular calcium increase and Ras-regulated activation of extracellular signal-regulated kinases. Moreover, TCR-induced phosphorylation of pp36-38, thought to play a role upstream of these pathways, was found to be reduced. In contrast, overexpression of wild-type ZAP-70 induced constitutive activation of nuclear factor of activated T cells. The ZAP-70 mutant studied here could be phosphorylated on tyrosine when associated to the TCR ζ chain and was able to bind p56lck. This result demonstrates that Tyr-492 and Tyr-493 are not responsible for the Src homology domain 2-mediated association of p56lck with ZAP-70. Our data are most consistent with a model in which recruitment to the TCR allows ZAP-70 autophosphorylation and binding to p56lck, which in turn phosphorylates Tyr-492 and/or Tyr-493 with consequent up-regulation of the ZAP-70 kinase activity. ZAP-70 will then be able to effectively control phosphorylation of its substrates and lead to gene activation
Effects of PDE4 inhibitors on lipopolysaccharide-induced priming of superoxide anion production from human mononuclear cells.
AIMS: Phosphodiesterase 4 (PDE4) inhibitors have been described as potent anti-inflammatory compounds, involving an increase in intracellular levels of cyclic 3',5'-adenosine monophosphate (AMP). The aim of this study was to compare the effects of selective PDE4 inhibitors, rolipram and RP 73-401 with the cell permeable analogue of cyclic AMP, dibutyryl-cyclic AMP (db-cAMP) and the anti-inflammatory cytokine interleukin-10 (IL-10) on superoxide anion production from peripheral blood mononuclear cells preincubated with lipopolysaccharide (LPS). MAJOR FINDINGS: We report that, after incubation of the cells with LPS, a large increase in superoxide anion production was observed. Rolipram or RP 73-401 (10(-8) to 10(-5) M) induced significant reductions of fMLP-induced superoxide anion production in cells incubated with or without LPS. The db-cAMP (10(-5) to 10(-3) M) also elicited dose-dependent inhibitions of the fMLP-induced superoxide anion production. In contrast, IL-10 (1 or 10 ng/ml) did not elicit a reduction in fMLP-induced superoxide anion production in both conditions. PRINCIPAL CONCLUSION: These results suggest that the inhibitory activity of PDE4 inhibitors on fMLP-induced production of superoxide anion production is mediated by db-cAMP rather than IL-10
Pre-exposure Prophylaxis (PrEP) for HIV prevention among men who have sex with men (MSM): A scoping review on PrEP service delivery and programming.
Background: Intimate partner violence (IPV) is a risk factor for developmental problems in offspring. Despite a high prevalence of IPV in the UK and elsewhere, the longer-term outcomes of offspring born to exposed mothers remain under-researched. Methods: Population-based cohort study. We assessed IPV prevalence by type and timing for 3,153 mother-child pairs with complete data within our study population and examined associations between IPV and offspring IQ. We used multiple-imputation to evaluate bias due to our exclusion of observations with missing covariate data. Results: Nearly one in five mothers reported IPV during the study period, with 17.6% reporting emotional violence and 6.8% reporting physical violence. Taking into account potential confounders, the IQ scores of children born to mothers exposed to physical violence remained lower than those of maternally unexposed children (full-scale IQ = â2.8 points [95%CI â4.9 to â0.7], verbal IQ = â2.2 [95%CI â4.4 to â0.1], performance IQ = â2.7 [95%CI â5.0 to â0.5]) and odds of below-average intelligence (IQ<90) remained increased for full-scale (OR 1.48 [95%CI 1.03 to 2.14] and performance IQ (OR 1.48 [95%CI 1.08 to 2.04]) but not verbal IQ (OR 1.06 [95%CI 0.69 to 1.64]). Most physical violence occurred postnatally, and relative odds were most substantial when mothers were exposed to violence across pre-/perinatal and postnatal study periods (OR performance IQ<90 = 2.97 [95%CI 1.30 to 6.82]). Conclusions: Maternal exposure to physical IPV is associated with lower offspring IQ at age 8. Associations persisted after adjusting for potential confounders and were driven by violence occurring postnatally
XtremWeb : une plate-forme de recherche sur le calcul global et pair Ă pair
ISBN 274620472XLa connection Ă grande Ă©chelle des ordinateurs aux rĂ©seaux de communication et les mĂ©canismes qui permettent leur interopĂ©rabilitĂ© (standardisation des protocoles, homogĂ©nĂ©isation des formats d'Ă©change, systĂšmes de nomage efïŹcace, sĂ©curisation des sites) motivent des tentatives de globalisation des ressources et des donnĂ©es Ă partir de systĂšmes de Calcul Global, Pair Ă Pair ou de GRID. Ces systĂšmes sont les prĂ©misses de l'Ă©mergence de systĂšmes d'exploitation Ă grande Ă©chelle. Dans cet article nous proposons d'abord de situer les systĂ©mes Pair Ă Pair par rapport aux autres structures de GRID en soulignant leur diffĂ©rences qui ont principalement une origine historique. Dans une deuxiĂšme partie nous prĂ©sentons une ratio- nalisation des systĂ©mes de Calcul Global et Pair Ă Pair. Nous dĂ©taillons ensuite la plate-forme XtremWeb qui constitue l'une des premiĂšres tentatives de gĂ©nĂ©ralisation du concept de paritĂ© entre les ressources appliquĂ© Ă la globalisation du processeur, de la mĂ©moire et du stockage. Nous terminons par la prĂ©sentation de quelques points durs en recherche : la sĂ©curisation des participants et la communication inter-noeud
The Role of Sugars, Hexokinase, and Sucrose Synthase in the Determination of Hypoxically Induced Tolerance to Anoxia in Tomato Roots
Phosphodiesterase 4 inhibitors and db-cAMP inhibit TNF-α release from human mononuclear cells. Effects of cAMP and cGMP-dependent protein kinase inhibitors
We investigated the effects of specific inhibitors of cAMP-dependent protein kinase (PKA) and cGMP-dependent protein kinase (PKG) on the inhibitory activity of phosphodiesterase (PDE) type 4 inhibitors and of the cell permeable analogue of cAMP, db-cAMP on LPS-induced TNF-α release from human mononuclear cells. Incubation from 30 min of mononuclear cells with dbcAMP (10â5 to 10â3 M), rolipram (10â9 M to 10â5 M) or Ro 20-1724 (10â9 M to 10â5 M) significantly inhibited LPS-induced TNF-α release. When mononuclear cells were preincubated for 30 min with the selective PKA inhibitor, H89 (10â4 M), but not with the selective PKG inhibitor, Rp-8-pCPT-cGMPs (10â4 M), a significant reduction of the inhibitory effect of db-cAMP was noted. Thirty min incubation of mononuclear cells with Rp-8-pCPT-cGMPs induced a significant reduction of the inhibitory activities of both rolipram and Ro 20-1724 (10â9 to 10â5 M) on LPS-induced TNF-α release, whereas H89 elicited a moderate, but significant inhibition. The present data indicate that db-cAMP inhibits TNF-α release from human mononuclear cells through a PKA-dependent mechanism. In contrast, PDE 4 inhibitors elicit their in vitro anti-inflammatory activities via a PKG-dependent rather than PKA-dependent activation
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