18,894 research outputs found
Conservative tolerance and confidence limits
Extension of exponential tolerance and confidence limits to class of distributions with monotone failure rat
Reliability growth during a development testing program
Binomial and trinomial mathematical models for reliability growth studies - statistical analysis of system failure
Tolerance and confidence limits for classes of distributions based on failure rate
Tolerance and confidence limits for classes of distributions based on failure rate
The effectiveness of parenting programmes: a review of Campbell reviews
Parenting practices predict important outcomes for children, and parenting programmes are potentially effective means of supporting parents to promote optimal parenting for pre-adolescent children. The aim of this review was to evaluate the effectiveness of parenting programmes by summarising findings of relevant systematic reviews published in the Campbell Library. Six Campbell systematic reviews evaluated the effectiveness of a range of parenting programmes in the primary and secondary prevention of behavioural problems (among children aged 0 – 3 years), early onset conduct disorder (among children aged 3 – 12 years), outcomes for parents and children with ADHD, outcomes for particular groups of parents and children (i.e., with intellectual disabilities and teenagers), and the psychosocial functioning of parents. The findings of these reviews show that parenting programmes can be effective in improving the emotional and behavioural adjustment of children in the first 12 years of life, in addition to enhancing the psychosocial wellbeing of their parents. The findings also suggest that further research is needed to assess effectiveness of programmes for specific subgroups of parents (e.g., fathers, teenagers, parents with intellectual disabilities) and to assess the long-term effectiveness of parenting programmes
RXTE confirmation of the intermediate polar status of IGR J15094-6649
Aims. To establish the X-ray properties of the intermediate polar candidate
IGR J15094-6649 and therefore confirm its inclusion into the class.
Methods. 42 856 s of X-ray data from RXTE was analysed. Frequency analysis
was used to constrain temporal variations and spectral analysis used to
characterise the emission and absorption properties.
Results. A spin period of 809.7+-0.6 s is present, revealed as a complex
pulse profile whose modulation depth decreases with increasing X-ray energy.
The spectrum is well fitted by either a 19+-4 keV Bremsstrahlung or
Gamma=1.8+-0.1 power law, with an iron emission line feature and significant
absorption in each case.
Conclusions. IGR J15094-6649 is confirmed to be an intermediate polar.Comment: 3 pages, 5 figures. Submitted to A&
Tests for exponentiality against NBUE alternatives: a Monte Carlo comparison
Testing of various classes of life distributions has been addressed in the
literature for more than 45 years. In this paper, we consider the problem of
testing exponentiality (which essentially implies no ageing) against positive
ageing which is captured by the fairly large class of new better than used in
expectation (NBUE) distributions. These tests of exponentiality against NBUE
alternatives are discussed and compared. The empirical size of the tests is
obtained by simulations. Power comparisons for different popular alternatives
are done using Monte Carlo simulations. These comparisons are made for both
small and large sample sizes. The paper concludes with a discussion in which
suggestions are made regarding the choices of the test when a particular
alternative is suspected
Dust yields in clumpy SN shells: SN 1987A revisited
We present a study of the effects of clumping on the emergent spectral energy
distribution (SED) from dusty supernova (SN) shells illuminated by a diffuse
radiation source distributed throughout the medium. (...) The fully 3D
radiation transport problem is solved using a Monte Carlo code, MOCASSIN, and
we present a set of models aimed at investigating the sensitivity of the SEDs
to various clumping parameters. We find that, contrary to the predictions of
analytical prescriptions, the combination of an optical and IR observational
data set is sufficient to constrain dust masses even in the case where
optically thick clumps are present. Using both smoothly varying and clumped
grain density distributions, we obtain new estimates for the mass of dust
condensed by the Type II SN 1987A by fitting the optical and infrared
spectrophotometric data of Wooden et al. (1993) at two epochs (day 615 and day
775). (...) From our numerical models we derive dust masses for SN 1987A that
are comparable to previous analytic clumped graphite grain mass estimates, and
at least two orders of magnitude below the 0.1-0.3 Msol that have been
predicted to condense as dust grains in primordial core collapse supernova
ejecta. This low condensation efficiency for SN 1987A is in contrast to the
case of SN 2003gd, for which a dust condensation efficiency as large as 0.12
has recently been estimated. (Abridged)Comment: accepted for publication in MNRAS. The paper contains 15 figures and
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Views of Coaching Practice Expressed by School-Based Coaches
This study reports on the views of coaching expressed by school-based coaches and coaching experts in response to observing the practice of a novice coach featured in a video. Researchers hypothesized that a coach participant\u27s observations about another coach\u27s practice would be a useful tool for examining participants\u27 beliefs about coaching. Researchers compared responses from school-based coaches to the responses of coaching experts and views expressed in leading coaching literature in order to examine the variation in school-based coaches\u27 views. Analysis of responses from both practicing coaches and coaching experts revealed eight themes that describe components of the videotaped coaching cycle: 1) coaching relationships; 2) the use of praise by the coach; 3) discussions of student learning; 4) how coaches respond to teachers\u27 questions; 5) how coaches prompt reflection; 6) how coaches address teacher knowledge and learning; 7) discussions of mathematics content; and, 8) facilitation of the coaching session. The analysis also revealed that these themes correspond to accepted domains of coaching knowledge reported in the coaching literature
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