6,780 research outputs found
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A longitudinal investigation of maternal and child 'anxious cognitions'
Overestimation of threat and underestimation of coping have been frequently reported amongst anxious adults and children. The current study examines the longitudinal relationship between mothers' anxious cognitions and expectations about their child, and children's anxious cognitions. 54 children (aged 10-11 years) and their mothers reported on their interpretation of ambiguous scenarios at two time points. Mothers also reported on their expectations about their child's reaction to ambiguous situations. Significant cross-sectional associations were found between mother and child anticipation of distress. Associations were most consistent between mothers' expectations and children's cognitions. Furthermore, based on regression analyses, mothers' expectations predicted change in children's anxious cognitions over time. Evidence for a reciprocal relationship, that child cognitions predict change in mothers' expectations, was found for girls. The results provide empirical support for potential influences on the development of children's 'anxious cognitive style,' and suggest targets for preventing and reducing maladaptive cognitions in children
The Specific Heat of a Ferromagnetic Film.
We analyze the specific heat for the vector model on a -dimensional
film geometry of thickness using ``environmentally friendly''
renormalization. We consider periodic, Dirichlet and antiperiodic boundary
conditions, deriving expressions for the specific heat and an effective
specific heat exponent, \alpha\ef. In the case of , for , by
matching to the exact exponent of the two dimensional Ising model we capture
the crossover for \xi_L\ra\infty between power law behaviour in the limit
{L\over\xi_L}\ra\infty and logarithmic behaviour in the limit
{L\over\xi_L}\ra0 for fixed , where is the correlation length in
the transverse dimensions.Comment: 21 pages of Plain TeX. Postscript figures available upon request from
[email protected]
Dimensional Crossover in the Large N Limit
We consider dimensional crossover for an Landau-Ginzburg-Wilson model
on a -dimensional film geometry of thickness in the large -limit. We
calculate the full universal crossover scaling forms for the free energy and
the equation of state. We compare the results obtained using ``environmentally
friendly'' renormalization with those found using a direct, non-renormalization
group approach. A set of effective critical exponents are calculated and
scaling laws for these exponents are shown to hold exactly, thereby yielding
non-trivial relations between the various thermodynamic scaling functions.Comment: 25 pages of PlainTe
A New Method of Measuring 81Kr and 85Kr Abundances in Environmental Samples
We demonstrate a new method for determining the 81Kr/Kr ratio in
environmental samples based upon two measurements: the 85Kr/81Kr ratio measured
by Atom Trap Trace Analysis (ATTA) and the 85Kr/Kr ratio measured by Low-Level
Counting (LLC). This method can be used to determine the mean residence time of
groundwater in the range of 10^5 - 10^6 a. It requires a sample of 100 micro-l
STP of Kr extracted from approximately two tons of water. With modern
atmospheric Kr samples, we demonstrate that the ratios measured by ATTA and LLC
are directly proportional to each other within the measurement error of +/-
10%; we calibrate the 81Kr/Kr ratio of modern air measured using this method;
and we show that the 81Kr/Kr ratios of samples extracted from air before and
after the development of the nuclear industry are identical within the
measurement error
Field Theory Entropy, the -theorem and the Renormalization Group
We consider entropy and relative entropy in Field theory and establish
relevant monotonicity properties with respect to the couplings. The relative
entropy in a field theory with a hierarchy of renormalization group fixed
points ranks the fixed points, the lowest relative entropy being assigned to
the highest multicritical point. We argue that as a consequence of a
generalized theorem Wilsonian RG flows induce an increase in entropy and
propose the relative entropy as the natural quantity which increases from one
fixed point to another in more than two dimensions.Comment: 25 pages, plain TeX (macros included), 6 ps figures. Addition in
title. Entropy of cutoff Gaussian model modified in section 4 to avoid a
divergence. Therefore, last figure modified. Other minor changes to improve
readability. Version to appear in Phys. Rev.
Simulational Study on Dimensionality-Dependence of Heat Conduction
Heat conduction phenomena are studied theoretically using computer
simulation. The systems are crystal with nonlinear interaction, and fluid of
hard-core particles. Quasi-one-dimensional system of the size of is simulated. Heat baths are put in both end:
one has higher temperature than the other. In the crystal case, the interaction
potential has fourth-order non-linear term in addition to the harmonic
term, and Nose-Hoover method is used for the heat baths. In the fluid case,
stochastic boundary condition is charged, which works as the heat baths.
Fourier-type heat conduction is reproduced both in crystal and fluid models in
three-dimensional system, but it is not observed in lower dimensional system.
Autocorrelation function of heat flux is also observed and long-time tails of
the form of , where denotes the dimensionality of the
system, are confirmed.Comment: 4 pages including 3 figure
The Change in Prevalence of Campylobacter on Chicken Carcasses During Processing: A Systematic Review
A systematic review was conducted to evaluate the change in prevalence of Campylobacter on chicken carcasses during processing. A structured literature search of 8 electronic databases using the key words for Campylobacter, chicken, and processing identified 1,734 unique citations. Abstracts were screened for relevance by 2 independent reviewers. Thirty-two studies described prevalence at more than one stage during processing and were included in this review. Of the studies that described the prevalence of Campylobacter on carcasses before and after specific stages of processing, the chilling stage had the greatest number of studies (9), followed by washing (6), defeathering (4), scalding (2), and evisceration (1). Studies that sampled before and after scalding or chilling, or both, showed that the prevalence of Campylobacter generally decreased immediately after the stage (scalding: 20.0 to 40.0% decrease; chilling: 100.0% decrease to 26.6% increase). The prevalence of Campylobacter increased after defeathering (10.0 to 72.0%) and evisceration (15.0%). The prevalence after washing was inconsistent among studies (23.0% decrease to 13.3% increase). Eleven studies reported the concentration of Campylobacter, as well as, or instead of, the prevalence. Studies that sampled before and after specific stages of processing showed that the concentration of Campylobacter decreased after scalding (minimum decrease of 1.3 cfu/g, maximum decrease of 2.9 cfu/mL), evisceration (0.3 cfu/g), washing (minimum 0.3 cfu/mL, maximum 1.1 cfu/mL), and chilling (minimum 0.2 cfu/g, maximum 1.7 cfu/carcass) and increased after defeathering (minimum 0.4 cfu/g, maximum 2.9 cfu/mL). Available evidence is sparse and suggests more data are needed to understand the magnitude and mechanism by which the prevalence and concentration of Campylobacter changes during processing. This understanding should help researchers and program developers identify the most likely points in processing to implement effective control efforts. For example, if contamination will occur during defeathering and likely during evisceration, critical control points postevisceration are likely to have a greater effect on the end product going to the consumer
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Ignoring Puff Counts: Another Shortcoming of the Federal Trade Commission Cigarette Testing Programme
OBJECTIVES; To examine reasons behind the failure of the Federal Trade Commission (FTC) to preserve puff count information from standard cigarette testing and to elucidate the importance of puff count to overall tar yields.METHODS; We reviewed industry documents on origins of the FTC test and data sets provided by the Tobacco Institute Testing Laboratory to the tobacco industry and FTC for reporting purposes.RESULTS; The majority of the tobacco industry argued for "dual reporting" of tar yields-both per cigarette and per puff. Despite a request from the Tobacco Institute in 1967 that puff count information be preserved, documents and recent communications with the FTC indicate that puff number data have not been maintained by the government. In contrast, for the cigarette industry, puff count data are a fundamental and routine part of testing and important to cigarette design. A sample of puff counts for cigarettes tested in 1996 (n = 471) shows that on average 100 mm cigarettes have 18% more puffs taken on them than do 85 mm cigarettes in standard tests (7.66 vs 9.03; p<0.01). The 10th percentile puff count is 6.8 and the 90th percentile is 8.8 for king size; the 10th percentile puff count is 8.2 and the 90th percentile is 10.0 for 100 mm cigarettes, indicating that puff counts can vary substantially among brands.CONCLUSIONS; The FTC has failed to seek or preserve puff count information that the industry finds important. Any standard test of tar and nicotine yields should at minimum preserve puff count information
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