20,515 research outputs found
Periodicity of ~155 days in solar electron fluence
In this paper we have investigated the occurrence rate of high energetic(E>10
MeV) solar electron flares measured by IMP-8 spacecraft of NASA for solar cycle
21 (June, 1976 to August, 1986) first time by three different methods to detect
periodicities accurately. Power-spectrum analysis confirms a periodicity ~155
days which is in consistent with the result of Chowdhury and Ray (2006), that
"Rieger periodicity" was operated throughout the cycle 21 and it is independent
on the energy of the electron fluxes.Comment: 11 pages of PDF version of MSWORD, 3 figures with 1 tabl
The SONYC survey: Towards a complete census of brown dwarfs in star forming regions
SONYC, short for "Substellar Objects in Nearby Young Clusters", is a survey
program to provide a census of the substellar population in nearby star forming
regions. We have conducted deep optical and near-infrared photometry in five
young regions (NGC1333, rho Ophiuchi, Chamaeleon-I, Upper Sco, and Lupus-3),
combined with proper motions, and followed by extensive spectroscopic campaigns
with Subaru and VLT, in which we have obtained more than 700 spectra of
candidate low-mass objects. We have identified and characterized more than 60
new substellar objects, among them a handful of objects with masses close to,
or below the Deuterium burning limit. Through SONYC and surveys by other
groups, the substellar IMF is now well characterized down to ~ 5 - 10 MJup, and
we find that the ratio of the number of stars with respect to brown dwarfs lies
between 2 and 6. A comprehensive survey of NGC 1333 reveals that, down to
~5MJup, free-floating objects with planetary masses are 20-50 times less
numerous than stars, i.e. their total contribution to the mass budget of the
clusters can be neglected.Comment: to appear in the proceedings of the conference 'Brown dwarfs come of
age', May 20-24 2013, Memorie della Societa Astronomica Italian
The effect of Cichorium intybus and Lotus corniculatus on nematode burdens and production in grazed lambs
This report was presented at the UK Organic Research 2002 Conference. The study was designed to examine the hypothesis that chicory (Cichorium intybus) and Lotus sp. (Lotus corniculatus) have the potential to affect the naturally acquired nematode burden in grazed lambs. Organic male castrate lambs (48) with a naturally acquired parasite burden grazed replicate combination plots (0.6 ha) of chicory, Lotus corniculatus, perennial ryegrass (Lolium perenne) and white clover (Trifolium repens). Lamb performance was determined by weekly weight gain and condition score assessments. Nematode burden was assessed by individual lamb faecal egg count (FEC) before and after drenching (levamisole). The range of parasitic helminths present was assessed by faecal culture and by total worm counts performed on a proportion of the lambs at slaughter. Weekly pasture larval counts (PLCs) were conducted on the trial plots. A concurrent small plot study (6 x 1m2 replicates) of each of the forages used in the grazing trial was run to assess the potential effect of forage type on the development and survival of Teladorsagia circumcincta assessed by weekly PLCs. Preliminary data suggest that lambs grazing chicory or a combination of lotus and chicory had lower FECs than those grazing PRG/WC, however there was no significant difference in the total worm counts
Spectroscopic study of unique line broadening and inversion in low-pressure microwave generated water plasmas
It was demonstrated that low pressure (~0.2 Torr) water vapor plasmas
generated in a 10 mm inner diameter quartz tube with an Evenson microwave
cavity show at least two features which are not explained by conventional
plasma models. First, significant (> 0.25 nm) hydrogen Balmer_ line broadening,
of constant width, up to 5 cm from the microwave coupler was recorded. Only
hydrogen, and not oxygen, showed significant line broadening. This feature,
observed previously in hydrogen-containing mixed gas plasmas generated with
high voltage dc and rf discharges was explained by some researchers to result
from acceleration of hydrogen ions near the cathode. This explanation cannot
apply to the line broadening observed in the (electrodeless) microwave plasmas
generated in this work, particularly at distances as great as 5 cm from the
microwave coupler. Second, inversion of the line intensities of both the Lyman
and Balmer series, again, at distances up to 5 cm from the coupler, were
observed. The line inversion suggests the existence of a hitherto unknown
source of pumping of the optical power in plasmas. Finally, it is notable that
other aspects of the plasma including the OH* rotational temperature and low
electron concentrations are quite typical of plasmas of this type.Comment: 27 pages, 7 figure
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An Examination of Motivation to Change and Neural Alcohol Cue Reactivity Following a Brief Intervention.
Background: Brief interventions represent a promising psychological intervention targeting individuals with heavy alcohol use. Motivation to change represents an individual's openness to engage in a behavior change strategy and is thought to be a crucial component of brief interventions. Neuroimaging techniques provide a translational tool to investigate the neurobiological mechanisms underlying potential mediators of treatment response, including motivation to change. Therefore, this study aimed to examine the effect of a brief intervention on motivation to change drinking behavior and neural alcohol taste cue reactivity. Methods: Non-treatment-seeking heavy drinkers were randomized to receive a brief drinking intervention (n = 22) or an attention-matched control (n = 24). Three indices of motivation to change were assessed at baseline and after the intervention or control session: importance, confidence, and readiness. Immediately following the intervention or control session, participants also underwent an functional magnetic resonance imaging (fMRI) during which they completed an alcohol taste cues paradigm. Results: There was a significant effect of the brief intervention on increasing ratings of importance of changing drinking behavior, but not on ratings of confidence or readiness to change. Ratings of importance after the intervention or control session were associated with neural alcohol taste cue reactivity, but notably, this effect was only significant for participants who received the intervention. Individuals in the intervention condition showed a positive association between ratings of importance and activation in the precuneus, posterior cingulate, and insula. Conclusions: The brief drinking intervention was successful at improving one dimension of motivation to change among non-treatment-seeking heavy drinkers. The brief intervention moderated the relationship between ratings of importance and brain activation in circuitry associated with interoceptive awareness and self-reflection. Together, findings represent an initial step toward understanding the neurobiological mechanisms through which a brief intervention may improve motivation to change
Scenario of inflationary cosmology from the phenomenological models
Choosing the three phenomenological models of the dynamical cosmological term
, viz., , and
where is the cosmic scale factor, it has been shown by
the method of numerical analysis that the three models are equivalent for the
flat Universe . The evolution plots for dynamical cosmological term
vs. time and also the cosmic scale factor vs. are drawn
here for . A qualitative analysis has been made from the plots which
supports the idea of inflation and hence expanding Universe.Comment: 12 latex pages with 12 figures; Replaced with the revised version;
Accepeted for `J. Non-lin. Frac. Phen. Sci. Engg.
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