51,663 research outputs found
A Challenge to All: Raising the Participation and Success of Women and Minorities in Mathematics, Science, and Technlogy
This issue of our journal is the product of a Virginia Mathematics and Science Coalition (VMSC) conference titled, Programs That Work and held in March, 2000 on the issues of raising both the levels of success and the levels of participation of women and minorities in mathematics, science, and technology. Traditionally, these two groups have had low rates of participation in these subjects, and we believe this situation can and must be changed. The conference was to Coalition\u27s first direct assault on the problem
The lichen flora of the Chagos Archipelago : including a comparison with other island and coastal tropical floras
The 1996 Chagos Expedition provided the first opportunity to study the archipelagoâs lichen flora. Seventeen of the 55 islands were ecologically investigated, some in more detail than others, and lists and representative collections of lichens have been assembled for many of them. In all, 67 taxa have been recorded, 52 to specific level. Although the islands have a low biodiversity for cryptogamic plants, as would be expected in terms of their relatively young age, remoteness and small terrestrial surface areas, those taxa that are present are often found in abundance and play significant ecological roles. There is a good correlation between total lichen biodiversity and island size, despite the fact that Cocos nucifera is such an important substratum for cryptogamic plants and its presence on all islands studied provides a consistently high associated species count. Comparisons of lichen floras for ten island and coastal tropical areas show good correlations (based on the Sörensen Coefficient) within the Indian Ocean as would be expected, but poorer correlations exist within and between Pacific Ocean and neotropical floras. Ranked correlations between Chagos and other floras are in the sequence Maldives > Laing Island > Aldabra > Tuamotu > Pitcairn > N.Mariana & Belize > Guadeloupe > Cook. When coefficients are calculated using only the Physciaceae, different correlations and sequences are derived, but the affinities of the Indian Ocean islands remain strong. However, although the lichen flora of Chagos is characteristic for an Indian Ocean, it is dominated by pantropical species
The effectiveness of teamwork training on teamwork behaviors and team performance : A systematic review and meta-analysis of controlled interventions
The objective of this study was to conduct a systematic review and meta-analysis of teamwork interventions that were carried out with the purpose of improving teamwork and team performance, using controlled experimental designs. A literature search returned 16,849 unique articles. The meta-analysis was ultimately conducted on 51 articles, comprising 72 (k) unique interventions, 194 effect sizes, and 8439 participants, using a random effects model. Positive and significant medium-sized effects were found for teamwork interventions on both teamwork and team performance. Moderator analyses were also conducted, which generally revealed positive and significant effects with respect to several sample, intervention, and measurement characteristics. Implications for effective teamwork interventions as well as considerations for future research are discussed
Extreme scattering events and Galactic dark matter
Extreme Scattering Events (ESEs) are attributed to radio-wave refraction by a
cloud of free-electrons crossing the line-of-sight. We present a new model in
which these electrons form the photo-ionized 'skin' of an underlying cool,
self-gravitating cloud in the Galactic halo. In this way we avoid the severe
over-pressure problem which afflicts other models. The UV flux in the Galactic
halo naturally generates electron densities of the right order. We demonstrate,
for the first time, a good reproduction of the prototypical ESE in the quasar
0954+658. The neutral clouds are a few AU in radius and have masses less than
about 10^{-3} solar. The observed rate of ESEs implies that a large fraction of
the mass of the Galaxy is in this form.Comment: 5 pp incl 3 figs, LaTeX, uses aas2pp4.sty. Minor revisions. ApJ
Letters in pres
Propagation-invariant beams with quantum pendulum spectra: from Bessel beams to Gaussian beam-beams
We describe a new class of propagation-invariant light beams with Fourier
transform given by an eigenfunction of the quantum mechanical pendulum. These
beams, whose spectra (restricted to a circle) are doubly-periodic Mathieu
functions in azimuth, depend on a field strength parameter. When the parameter
is zero, pendulum beams are Bessel beams, and as the parameter approaches
infinity, they resemble transversely propagating one-dimensional Gaussian
wavepackets (Gaussian beam-beams). Pendulum beams are the eigenfunctions of an
operator which interpolates between the squared angular momentum operator and
the linear momentum operator. The analysis reveals connections with Mathieu
beams, and insight into the paraxial approximation.Comment: 4 pages, 3 figures, Optics Letters styl
Do depositors care about enforcement actions?
Since 1990, federal bank supervisors have publicly announced formal enforcement actions. This change in regime provides a natural laboratory to test two propositions: (1) claims by economists that putting confidential supervisory information in the public domain will enhance market discipline and (2) claims by bank supervisors that releasing such data will spark runs. To evaluate these propositions, we measure depositor reaction to 87 Federal Reserve announcements of enforcement actions. We compare deposit growth rates and yield spreads before and after the announcements at the sample banks and a control group of peer banks. The data show no evidence of unusual deposit withdrawals or spread increases at the sample banks following the announcements of formal actions. These results suggest that public announcements of enforcement actions did not spark bank runs or enhance depositor discipline. Apparently, depositors did not care a great deal about our sample actions.Bank supervision ; Deposit insurance
Microeconomics of Technology Adoption
There is an emerging consensus among macro-economists that differences in technology across countries accounts for the major differences in per-capita GDP and the wages of workers with similar skills across countries. Accounting for differences in technology levels across countries thus can go a long way towards understanding global inequality. One mechanism by which poorer countries can catch up with richer countries is through technological diffusion, the adoption by low-income countries of the advanced technologies produced in high-income countries. In this survey, we examine recent micro studies that focus on understanding the adoption process. If technological diffusion is a major channel by which poor countries can develop, it must be the case that technology adoption is incomplete or the inputs associated with the technologies are under-utilized in poor, or slow-growing economies. Thus, obtaining a better understanding of the constraints on adoption are useful in understanding a major component of growth.technology adoption, review
Statistics of some atmospheric turbulence records relevant to aircraft response calculations
Methods for characterizing atmospheric turbulence are described. The methods illustrated include maximum likelihood estimation of the integral scale and intensity of records obeying the von Karman transverse power spectral form, constrained least-squares estimation of the parameters of a parametric representation of autocorrelation functions, estimation of the power spectra density of the instantaneous variance of a record with temporally fluctuating variance, and estimation of the probability density functions of various turbulence components. Descriptions of the computer programs used in the computations are given, and a full listing of these programs is included
The unavoidable costs of ethnicity : a review of evidence on health costs
This report was commissioned by the Advisory Committee on Resource Allocation (ACRA), and prepared
by the Centre for Health Services Studies (CHESS) and the Centre for Research in Ethnic Relations
(CRER) at the University of Warwick. The NHS Executive does not necessarily assent to the factual
accuracy of the report, nor necessarily share the opinions and recommendations of the authors.
The study reviews the evidence concerning the degree to which the presence of populations of minority
ethnic origin was associated with âunavoidable additional costsâ in health service delivery. While local
health authorities retail full autonomy in their use of funds allocated to them under the Hospital and
Community Health Services formula, the size of that budget is governed by a set of weightings applied to
their population, to allow for factors known to influence levels of need, and the costs of providing services.
The study began by considering the definitions used in describing âethnicityâ and ethnic groups in relevant
medical and social policy literature. It is clear that no fixed set of terms can be adopted, and that flexibility
is required to respond to social changes. The terms used in the 1991 Census, with additions to allow for
local and contemporary developments, provide a suitable baseline but require additional information on
religion language and migration history for clinical and health service delivery planning.
There have been notable developments in health service strategy to meet the needs of black and minority
ethnic groups which have been encouraged by good practice guidelines and local initiatives. Together with
research into epidemiology and ethnic monitoring of services, these have enlarged understanding of the
impact of diversity. A conceptual model is developed which explores the potential for such diversity to lead
to variations in the cost of providing health services to a multi-ethnic population.
The research team reviewed the existing published evidence relating to ethnic health and disease treatment
in medical, social science, academic and practitioner literature, using conventional techniques. Additional
evidence was located through trawls of âgreyâ literature in specialist collections, and through contacting all
English health districts with a request for information. A number of authorities and trusts provided written
and oral evidence, and a bibliography of key materials is provided.
Key issues considered include the need for and use of, interpreter and translation services, the incidence of
âethnically-specificâ disease, and variations in the prevalence and cost of treating âcommonâ conditions in
minority ethnic populations. Sources of variation are discussed, and a âscopingâ approach adopted to
explore the extent to which these variations could be adequately modelled. It is clear that while some
additional costs can be identified, and seen to be unavoidable, there are other areas where the presence of
minority populations may lead to lessened pressures on budgets, or where provision of âethnic-specificâ
facilities may be alternative to existing needs.
The literature provides a range of estimates which can be used in a modelling exercise, but is deficient in
many respects, particularly in terms of precise costs associated with procedure and conditions, or in
associating precise and consistent categories of ethnic group with epidemiological and operational service
provision data. Certain other activities require funding to set them up, and may not be directly related to
population size. There is considerable variation in the approaches adopted by different health authorities,
and many services are provided by agencies not funded by NHS budgets. The study was completed before
the announcement of proposed changes in health service commissioning which may have other implications
for ethnic diversity.
The presence of minorities is associated with the need to provide additional services in respect of
interpreting and translation, and the media of communication.
In order to achieve clinical effectiveness, a range of advocacy support facilities or alternative models of
provision seem to be desirable.
Ethnic diversity requires adaptation and additional evidence in order to inform processes of consultation
and commissioning.
Minority populations do create demands for certain additional specific clinical services not required by the
bulk of the majority population: it is not yet clear to what extent the reverse can be stated since research on
âunder-useâ is less well developed.
Some variations in levels of need, particularly those relating to established clinical difference in
susceptibility or deprivation, are already incorporated in funding formulae although it is not clear how far
the indicators adequately reflect these factors.
Costs are not necessarily simply related to the size of minority populations.
The provision of services to meet minority needs is not always a reflection of their presence, but has
frequently depended upon the provision of additional specific funds.
There is a consensus that the NHS research and development strategy should accept the need for more work
to establish the actual levels of need and usage of service by ethnic minority groups, and that effort should
be made to use and improve the growing collection of relevant information through ethnic monitoring
activities.
A variety of modelling techniques are suggested, and can be shown to have the potential to provide
practical guidance to future policy in the field.
Current data availability at a national or regional scale is inadequate to provide estimates of the âadditional
costs of ethnicityâ but locally collected data and the existence of relevant policy initiatives suggest that a
focused study in selected districts would provide sufficiently robust information to provide reliable
estimates.
The review has demonstrated that there are costs associated with the presence of minority ethnic groups in
the population which can be shown to be unavoidable and additional, but that others are either âdesirableâ or
âalternativeâ. It would be wrong to assume that all cost pressures of this nature are in the same direction.
Our study has drawn attention to deficiencies in data collection and budgeting which may hinder
investigation of the effectiveness of the service in general. The process of drawing attention to ethnic
minority needs itself leads to developments in services which are functional and desirable for the majority
population
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