1,608 research outputs found
Measurements of the Neutron Spectrum n the Tevatron Tunnel with Application to the SSC
This is an agreement between Fermilab and the experimenters to carry out an experiment to determine the radiation background in the Tevatron tunnel. The goal will be to determine the spectrum of neutrons in the tunnel while the Tevatron is operating (while gating all effects of the Main Ring ltout U) and for the Main Ring plus Tevatron (no gating). The detectors will also give information on the flux of charged particles near the Tevatron. The purpose is to obtain information on radiation fields in the tunnel in order to estimate possible radiation effects on equipment in such an environment. These data will be useful in desiqning the SSC tunnel and in assessing detector backgrounds. A preliminary description of the experiment is given in a memorandum from J.B. McCaslin to M. Tiqner, dated July 11, 1985, which is attached as Appendix I
Hydrous sludges, further characterizations and a model system. Project 2962, report two : a progress report to the National Council of the Paper Industry for Air and Stream Improvement, Inc.
"February 29, 1972.""The Institute of Paper Chemistry, S. C. Nagel ... Rajai H. Atalla ... John W. Swanson ...
Self-trapping and stable localized modes in nonlinear photonic crystals
We predict the existence of stable nonlinear localized modes near the band
edge of a two-dimensional reduced-symmetry photonic crystal with a Kerr
nonlinearity. Employing the technique based on the Green function, we reveal a
physical mechanism of the mode stabilization associated with the effective
nonlinear dispersion and long-range interaction in the photonic crystals.Comment: 4 pages (RevTex) with 5 figures (EPS
Stressor- and Corticotropin releasing Factor-induced Reinstatement and Active Stress-related Behavioral Responses are Augmented Following Long-access Cocaine Self-administration by Rats
Rationale Stressful events during periods of drug abstinence likely contribute to relapse in cocaine-dependent individuals. Excessive cocaine use may increase susceptibility to stressor-induced relapse through alterations in brain corticotropin-releasing factor (CRF) responsiveness.
Objectives This study examined stressor- and CRF-induced cocaine seeking and other stress-related behaviors in rats with different histories of cocaine self-administration (SA).
Materials and methods Rats self-administered cocaine under short-access (ShA; 2 h daily) or long-access (LgA; 6 h daily) conditions for 14 days or were provided access to saline and were tested for reinstatement by a stressor (electric footshock), cocaine or an icv injection of CRF and for behavioral responsiveness on the elevated plus maze, in a novel environment and in the light–dark box after a 14- to 17-day extinction/withdrawal period.
Results LgA rats showed escalating patterns of cocaine SA and were more susceptible to reinstatement by cocaine, EFS, or icv CRF than ShA rats. Overall, cocaine SA increased activity in the center field of a novel environment, on the open arms of the elevated plus maze, and in the light compartment of a light–dark box. In most cases, the effects of cocaine SA were dependent on the pattern/amount of cocaine intake with statistically significant differences from saline self-administering controls only observed in LgA rats.
Conclusions When examined after several weeks of extinction/ withdrawal, cocaine SA promotes a more active pattern of behavior during times of stress that is associated with a heightened susceptibility to stressor-induced cocaine-seeking behavior and may be the consequence of augmented CRF regulation of addiction-related neurocircuitry
Response to Methylphenidate in Children with Attention Deficit Hyperactivity Disorder and Manic Symptoms in the Multimodal Treatment Study of Children with Attention Deficit Hyperactivity Disorder Titration Trial
Objective:
Recent reports raise concern that children with attention deficit hyperactivity disorder (ADHD) and
some manic symptoms may worsen with stimulant treatment. This study examines the response to
methylphenidate in such children.
Methods:
Data from children participating in the 1-month methylphenidate titration trial of the Multimodal
Treatment Study of Children with ADHD were reanalyzed by dividing the sample into children with and
without some manic symptoms. Two “mania proxies” were constructed using items from the Diagnostic
Interview Schedule for Children (DISC) or the Child Behavior Checklist (CBCL). Treatment response and
side effects are compared between participants with and without proxies.
Results:
Thirty-two (11%) and 29 (10%) participants fulfilled criteria for the CBCL mania proxy and DISC
mania proxy, respectively. Presence or absence of either proxy did not predict a greater or lesser response or
side effects.
Conclusion:
Findings suggest that children with ADHD and manic symptoms respond robustly to
methylphenidate during the first month of treatment and that these children are not more likely to have an
adverse response to methylphenidate. Further research is needed to explore how such children will respond
during long-term treatment. Clinicians should not a priori avoid stimulants in children with ADHD and some
manic symptoms
Ion irradiation of Fe-Fe oxide core-shell nanocluster films: Effect of interface on stability of magnetic properties
A cluster deposition method was used to produce films of loosely aggregated
nanoclusters (NC) of Fe core-Fe3O4 shell or fully oxidized Fe3O4. Films of
these NC on Si(100) or MgO(100)/Fe3O4(100) were irradiated to 10^16 Si2+/cm2
near room temperature using an ion accelerator. Ion irradiation creates
structural change in the NC film with corresponding chemical and magnetic
changes which depend on the initial oxidation state of the cluster. Films were
characterized using magnetometry (hysteresis, first order reversal curves),
microscopy (transmission electron, helium ion), and x-ray diffraction. In all
cases, the particle sizes increased due to ion irradiation, and when a core of
Fe is present, irradiation reduces the oxide shells to lower valent Fe species.
These results show that ion irradiated behavior of the nanocluster films
depends strongly on the initial nanostructure and chemistry, but in general
saturation magnetization decreases slightly.Comment: 25 pages, 4 tables, 6 figure
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Analysis of potential systematics
We analyze the density field of galaxies observed by the Sloan Digital Sky
Survey (SDSS)-III Baryon Oscillation Spectroscopic Survey (BOSS) included in
the SDSS Data Release Nine (DR9). DR9 includes spectroscopic redshifts for over
400,000 galaxies spread over a footprint of 3,275 deg^2. We identify,
characterize, and mitigate the impact of sources of systematic uncertainty on
large-scale clustering measurements, both for angular moments of the
redshift-space correlation function and the spherically averaged power
spectrum, P(k), in order to ensure that robust cosmological constraints will be
obtained from these data. A correlation between the projected density of stars
and the higher redshift (0.43 < z < 0.7) galaxy sample (the `CMASS' sample) due
to imaging systematics imparts a systematic error that is larger than the
statistical error of the clustering measurements at scales s > 120h^-1Mpc or k
< 0.01hMpc^-1. We find that these errors can be ameliorated by weighting
galaxies based on their surface brightness and the local stellar density. We
use mock galaxy catalogs that simulate the CMASS selection function to
determine that randomly selecting galaxy redshifts in order to simulate the
radial selection function of a random sample imparts the least systematic error
on correlation function measurements and that this systematic error is
negligible for the spherically averaged correlation function. The methods we
recommend for the calculation of clustering measurements using the CMASS sample
are adopted in companion papers that locate the position of the baryon acoustic
oscillation feature (Anderson et al. 2012), constrain cosmological models using
the full shape of the correlation function (Sanchez et al. 2012), and measure
the rate of structure growth (Reid et al. 2012). (abridged)Comment: Matches version accepted by MNRAS. Clarifications and references have
been added. See companion papers that share the "The clustering of galaxies
in the SDSS-III Baryon Oscillation Spectroscopic Survey:" titl
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