6,879 research outputs found
The impact of labour regulations : measuring the effectiveness of legal norms in a developing country.
Measurement of Resonance Parameters of Orbitally Excited Narrow B^0 Mesons
We report a measurement of resonance parameters of the orbitally excited
(L=1) narrow B^0 mesons in decays to B^{(*)+}\pi^- using 1.7/fb of data
collected by the CDF II detector at the Fermilab Tevatron. The mass and width
of the B^{*0}_2 state are measured to be m(B^{*0}_2) =
5740.2^{+1.7}_{-1.8}(stat.) ^{+0.9}_{-0.8}(syst.) MeV/c^2 and \Gamma(B^{*0}_2)
= 22.7^{+3.8}_{-3.2}(stat.) ^{+3.2}_{-10.2}(syst.) MeV/c^2. The mass difference
between the B^{*0}_2 and B^0_1 states is measured to be
14.9^{+2.2}_{-2.5}(stat.) ^{+1.2}_{-1.4}(syst.) MeV/c^2, resulting in a B^0_1
mass of 5725.3^{+1.6}_{-2.2}(stat.) ^{+1.4}_{-1.5}(syst.) MeV/c^2. This is
currently the most precise measurement of the masses of these states and the
first measurement of the B^{*0}_2 width.Comment: 7 pages, 1 figure, 1 table. Submitted to Phys.Rev.Let
Measurement of the fraction of t-tbar production via gluon-gluon fusion in p-pbar collisions at sqrt(s)=1.96 TeV
We present a measurement of the ratio of t-tbar production cross section via
gluon-gluon fusion to the total t-tbar production cross section in p-pbar
collisions at sqrt{s}=1.96 TeV at the Tevatron. Using a data sample with an
integrated luminosity of 955/pb recorded by the CDF II detector at Fermilab, we
select events based on the t-tbar decay to lepton+jets. Using an artificial
neural network technique we discriminate between t-tbar events produced via
q-qbar annihilation and gluon-gluon fusion, and find
Cf=(gg->ttbar)/(pp->ttbar)<0.33 at the 68% confidence level. This result is
combined with a previous measurement to obtain the most precise measurement of
this quantity, Cf=0.07+0.15-0.07.Comment: submitted to Phys. Rev.
Validity and worth in the science curriculum: learning school science outside the laboratory
It is widely acknowledged that there are problems with school science in many developed countries of the world. Such problems manifest themselves in a progressive decline in pupil enthusiasm for school science across the secondary age range and the fact that fewer students are choosing to study the physical sciences at higher levels and as careers. Responses to these developments have included proposals to reform the curriculum, pedagogy and the nature of pupil discussion in science lessons. We support such changes but argue from a consideration of the aims of science education that secondary school science is too rooted in the science laboratory; substantially greater use needs to be made of out-of-school sites for the teaching of science. Such usage should result in a school science education that is more valid and more motivating and is better at fulfilling defensible aims of school science education. Our contention is that laboratory-based school science teaching needs to be complemented by out-of-school science learning that draws on the actual world (e.g. through fieldtrips), the presented world (e.g. in science centres, botanic gardens, zoos and science museums) and the virtual worlds that are increasingly available through information and communications technologies (ICT)
The globalization strategies of five Asian tobacco companies: : An analytical framework
With 30% of the world\u27s smokers, two million deaths annually from tobacco use, and rising levels of tobacco consumption, the Asian region is recognised as central to the future of global tobacco control. There is less understanding, however, of how Asian tobacco companies with regional and global aspirations are contributing to the global burden of tobacco-related disease and death. This introductory article sets out the background and rationale for this special issue on \u27The Emergence of Asian Tobacco Companies: Implications for Global Health Governance\u27. The article discusses the core questions to be addressed and presents an analytical framework for assessing the globalisation strategies of Asian tobacco firms. The article also discusses the selection of the five case studies, namely as independent companies in Asia which have demonstrated concerted ambitions to be a major player in the world market
A short introduction into Bayesian evaluation of informative hypotheses as an alternative to exploratory comparisons of multiple group means
Search for lepton flavor violating decays of a heavy neutral particle in p-pbar collisions at root(s)=1.8 TeV
We report on a search for a high mass, narrow width particle that decays
directly to e+mu, e+tau, or mu+tau. We use approximately 110 pb^-1 of data
collected with the Collider Detector at Fermilab from 1992 to 1995. No evidence
of lepton flavor violating decays is found. Limits are set on the production
and decay of sneutrinos with R-parity violating interactions.Comment: Figure 2 fixed. Reference 4 fixed. Minor changes to tex
First-principles Electronic Structure of Superconductor CaAlOFeP: Comparison with LaFePO and CaAlOFeAs
We investigate the electronic structures of iron-based superconductors having
perovskite-like blocking layers, %CaAlOFe(AsP)
from first principles. CaAlOFeP and
CaAlOFeAs from first principles.
CaAlOFeP is found to have two hole-like Fermi surfaces
around , and one hole-like Fermi surface around M in the unfolded
Brillouin zone. This is in contrast with LaFePO, where no Fermi surface is
found around M. The relationship of their band structures and measured
transition temperatures of superconductivity is discussed. The number of Fermi
surfaces in CaAlOFeP is also different from that of
CaAlOFeAs, in which only one Fermi surface is formed around
. Analysis using maximally localized Wannier functions clarifies that
the differences between their band structures originate mainly from the
pnictogen height. We then analyze the alloying effect on the electronic
structure of CaAlOFeAsP. It is found that its electronic
structure is similar to that of CaAlOFeP and
CaAlOFeAs with the average crystal structure, though
CaAlOFeAsP contains the pnictogen height disorder. We calculate
the generalized susceptibility for CaAlOFe(AsP)
and clarify the factors determining its tendency.Comment: 5 figures, to be published in J. Phys. Soc. Jp
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