888 research outputs found
Evolution of Near-Sun Solar Wind Turbulence
This paper presents a preliminary analysis of the turbulence spectrum of the
solar wind in the near-Sun region R < 50 Rs, obtained from interplanetary
scintillation measurements with the Ooty Radio Telescope at 327 MHz. The
results clearly show that the scintillation is dominated by density
irregularities of size about 100 - 500 km. The scintillation at the small-scale
side of the spectrum, although significantly less in magnitude, has a flatter
spectrum than the larger-scale dominant part. Furthermore, the spectral power
contained in the flatter portion rapidly increases closer to the Sun. These
results on the turbulence spectrum for R < 50 Rs quantify the evidence for
radial evolution of the small-scale fluctuations (</= 50 km) generated by
Alfven waves.Comment: 8 pages, 5 figures, To appear in "Magnetic Coupling between the
Interior and the Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten,
Astrophysics and Space Science Proceedings, Springer-Verlag, Heidelberg,
Berlin, 200
Valorisation of a water hyacinth in vermicomposting using an epigeic earthworm Perionyx excavatus in Central Vietnam
The feasibility of vermicomposting water hyacinth (WH) [Eichhornia crassipes (Mart.) Solms] mixed with pig manure (PM) in different proportions was tested using tropical composting earthworm Perionyx excavatus. Earthworms grew and reproduced normally until the incorporation of 50% WH in initial substrate. Higher water hyacinth proportions induced earthworms' mortality and significantly affected the numbers of hatchlings and cocoons produced during vermicomposting period. The influence of the application of compost/vermicompost obtained from water hyacinth mixed with pig manure was also studied on seeds germination. Only water hyacinth substrate with 25% WH + 75% PM enhanced seeds germination for Oryza sp. and Nasturtium officinale. At the end of experiments, a significant decrease was observed in organic carbon content for each tested substrates (S1 to S8), in total nitrogen (N) for substrates containing 70% to 100% of water hyacinth (S5 to S3) and compost substrates (S1 and S2). An important decrease was also noted in total potassium for all vermicompost substrates (S3 to S8), in total magnesium for composted substrates (S1 and S2), and in C/N ratio for substrates containing 0% to 50% of water hyacinth (S8 to S6). Whereas total N in vermicompost containing 0% to 50% of water hyacinth (S8 to S6), total phosphorus, total potassium in composted substrates (S1 and S2), total magnesium in vermicompost substrates (S3 to S8) and C:N ratio in substrates containing 70% to 100% of water hyacinth (S5 to S3) expressed a significant increase after eight weeks. The result suggested that water hyacinth could be potentially useful as raw material in vermicomposting and biofertilizing if mixed with 75% of pig manure
Nickel ion level in scoliotic patients implanted with nitrogen plasma surface modified nickel-titanium superelastic spinal implant
published_or_final_versionThe 3rd International NanoElectronics Conference (INEC), Hong Kong, 3-8 January 2010. In Proceedings of the 3rd INEC, 2010, p. 136
Comparative Study of Superabsorbent Polymers and Pre‐soaked Pumice as Internal Curing Agents in Rice Husk Ash Based High‐Performance Concrete
Utilisation of superabsorbent polymers (SAP) and pre‐soaked lightweight aggregates (LWA) as internal
curing (IC) agents for the mitigation of autogenous shrinkage and micro‐cracking of high strength/highperformance
concrete (HSC/HPC) have been well researched and documented in literature. Rice husk
ash (RHA) on the other hand has been adjudged to be of good pozzolanic activity and a possible
alternative to silica fume (SF) in low water/binder (W/B) concrete production. An experimental
comparative study was conducted in the current work to assess the effectiveness of the two known ICagents
on rice husk ash (RHA) based HPC. HPC mixtures of fc,cube28=60 MPa minimum target strength
produced and internally cured with 0.3% content of SAP by weight of binder (bwob) and varied content
of pre‐soaked pumice (5 to 10% in steps of 2.5%) by weight of coarse aggregate (bwocg) were cast using
100 mm cubes samples. Thereafter, the samples were cured for 7, 14, 28 and 56 days by water
immersion before subjecting them to compressive strength test. The results showed 0.2% bwob SAP
HPC (SHPC1) to be the best performed internally cured HPC at the early ages with similar long‐term
strength values as 5 and 7.5% bwocg saturated pumiced HPC (PHPC1&2). The study thereby
recommends SAP content of 0.2% bwob and saturated pumice content up to 7.5% bwocg for use as ICagent
in HPC
Ethnic and sex differences in the incidence of hospitalized acute myocardial infarction: British Columbia, Canada 1995-2002
<p>Abstract</p> <p>Background</p> <p>As populations in Western countries continue to change in their ethnic composition, there is a need for regular surveillance of diseases that have previously shown some health disparities. Earlier data have already demonstrated high rates of cardiovascular mortality among South Asians and relatively lower rates among people of Chinese descent. The aim of this study was to describe the differences in the incidence of hospitalized acute myocardial infarction (AMI) among the three largest ethnic groups in British Columbia (BC), Canada.</p> <p>Methods</p> <p>Using hospital administrative data, we identified all patients with incident AMI in BC between April 1, 1995, and March 31, 2002. Census data from 2001 provided the denominator for the entire BC population. Ethnicity was determined using validated surname analysis and applied to the census and hospital administrative datasets. Direct age standardization was used to compare incidence rates.</p> <p>Results</p> <p>A total of 34,848 AMI cases were identified. Among men, South Asians had the highest age standardized rate of AMI hospitalization at 4.97/1000 population/year, followed by Whites at 3.29, and then Chinese at 0.98. Young South Asian men, in particular, showed incidence rates that were double that of young Whites and ten times that of young Chinese men. South Asian women also had the highest age-standardized rate of AMI hospitalization at 2.35/1000 population/year, followed by White women (1.53) and Chinese women (0.49).</p> <p>Conclusions</p> <p>South Asians continue to have a higher incidence of hospitalized AMI while incidence rates among Chinese remain low. Ethnic differences are most notable among younger men.</p
Endogenous Signaling by Omega-3 Docosahexaenoic Acid-derived Mediators Sustains Homeostatic Synaptic and Circuitry Integrity
The harmony and function of the complex brain circuits and synapses are sustained mainly by excitatory and inhibitory neurotransmission, neurotrophins, gene regulation, and factors, many of which are incompletely understood. A common feature of brain circuit components, such as dendrites, synaptic membranes, and other membranes of the nervous system, is that they are richly endowed in docosahexaenoic acid (DHA), the main member of the omega-3 essential fatty acid family. DHA is avidly retained and concentrated in the nervous system and known to play a role in neuroprotection, memory, and vision. Only recently has it become apparent why the surprisingly rapid increases in free (unesterified) DHA pool size take place at the onset of seizures or brain injury. This phenomenon began to be clarified by the discovery of neuroprotectin D1 (NPD1), the first-uncovered bioactive docosanoid formed from free DHA through 15-lipoxygenase-1 (15-LOX-1). NPD1 synthesis includes, as agonists, oxidative stress and neurotrophins. The evolving concept is that DHA-derived docosanoids set in motion endogenous signaling to sustain homeostatic synaptic and circuit integrity. NPD1 is anti-inflammatory, displays inflammatory resolving activities, and induces cell survival, which is in contrast to the pro-inflammatory actions of the many of omega-6 fatty acid family members. We highlight here studies relevant to the ability of DHA to sustain neuronal function and protect synapses and circuits in the context of DHA signalolipidomics. DHA signalolipidomics comprises the integration of the cellular/tissue mechanism of DHA uptake, its distribution among cellular compartments, the organization and function of membrane domains containing DHA phospholipids, and the precise cellular and molecular events revealed by the uncovering of signaling pathways regulated by docosanoids endowed with prohomeostatic and cell survival bioactivity. Therefore, this approach offers emerging targets for prevention, pharmaceutical intervention, and clinical translation involving DHA-mediated signaling
Search for Pair Production of Scalar Top Quarks Decaying to a tau Lepton and a b Quark in ppbar Collisions at sqrt{s}=1.96 TeV
We search for pair production of supersymmetric top quarks (~t_1), followed
by R-parity violating decay ~t_1 -> tau b with a branching ratio beta, using
322 pb^-1 of ppbar collisions at sqrt{s}=1.96 TeV collected by the CDF II
detector at Fermilab. Two candidate events pass our final selection criteria,
consistent with the standard model expectation. We set upper limits on the
cross section sigma(~t_1 ~tbar_1)*beta^2 as a function of the stop mass
m(~t_1). Assuming beta=1, we set a 95% confidence level limit m(~t_1)>153
GeV/c^2. The limits are also applicable to the case of a third generation
scalar leptoquark (LQ_3) decaying LQ_3 -> tau b.Comment: 7 pages, 2 eps figure
Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron
We study the underlying event in proton-antiproton collisions by examining
the behavior of charged particles (transverse momentum pT > 0.5 GeV/c,
pseudorapidity |\eta| < 1) produced in association with large transverse
momentum jets (~2.2 fb-1) or with Drell-Yan lepton-pairs (~2.7 fb-1) in the
Z-boson mass region (70 < M(pair) < 110 GeV/c2) as measured by CDF at 1.96 TeV
center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan
production) or the leading jet (in high-pT jet production) in each event to
define three regions of \eta-\phi space; toward, away, and transverse, where
\phi is the azimuthal scattering angle. For Drell-Yan production (excluding the
leptons) both the toward and transverse regions are very sensitive to the
underlying event. In high-pT jet production the transverse region is very
sensitive to the underlying event and is separated into a MAX and MIN
transverse region, which helps separate the hard component (initial and
final-state radiation) from the beam-beam remnant and multiple parton
interaction components of the scattering. The data are corrected to the
particle level to remove detector effects and are then compared with several
QCD Monte-Carlo models. The goal of this analysis is to provide data that can
be used to test and improve the QCD Monte-Carlo models of the underlying event
that are used to simulate hadron-hadron collisions.Comment: Submitted to Phys.Rev.
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