4,541 research outputs found
Observations of Dispersion Cancellation of Entangled Photon Pairs
An experimental study of the dispersion cancellation occurring in
frequency-entangled photon pairs is presented. The approach uses time-resolved
up conversion of the pairs, which has temporal resolution at the fs level, and
group-delay dispersion sensitivity of under
experimental conditions. The cancellation is demonstrated with dispersion
stronger than in the signal and idler
modes. The observations represent the generation, compression, and
characterization of ultrashort biphotons with correlation width as small as 6.8
times the degenerate optical period.Comment: 5 pages, 3 figure
Moving beyond the ‘language problem': developing an understanding of the intersections of health, language and immigration status in interpreter-mediated health encounters
Health systems internationally are dealing with greater diversity in patient populations. However the focus on ‘the language problem’ has meant little attention is paid to diversity within and between migrant populations; and how interpreted consultations are influenced by intersecting migratory, ethnicity and sociodemographic variables. Our analysis of the experiences of patients, health care providers and interpreters in Scotland evidences the need to move beyond language, addressing multiple hidden inequalities in health care access and provision that operate in both clinic and, especially, home-based settings. We call for a practice-evidenced research agenda promoting cultural communication across health care and home settings, acknowledging immigration status as a social determinant of health.
Sur le plan international, des systèmes de santé font face à une diversité croissante dans ses populations de patients. Cependant, l’accent sur ‘le problème de langue’ se traduit dans une manque d’attention à la diversité a l’intérieur même et entre des populations des migrants; et la façon par laquelle des variables migratoire, ethnique et sociodémographique influencent elles-mêmes des consultations interprétées. Notre analyse des expériences des patients, des professionnels fournissant de soins de santé et des interprètes offre des preuves du besoin de dépasser le problème de langue. Et en faisant cela, nous adressons des multiples inégalités, souvent cachées dans des contextes de soins de santé, dans les milieux clinique et domicile. Nous proposons un programme de recherche basé sur la pratique, qui favorise la communication culturelle dans des milieux clinique et domicile, et qui reconnait le statut d’immigration comme un déterminant social de la santé
Thermodynamic metrics and optimal paths
A fundamental problem in modern thermodynamics is how a molecular-scale
machine performs useful work, while operating away from thermal equilibrium
without excessive dissipation. To this end, we derive a friction tensor that
induces a Riemannian manifold on the space of thermodynamic states. Within the
linear-response regime, this metric structure controls the dissipation of
finite-time transformations, and bestows optimal protocols with many useful
properties. We discuss the connection to the existing thermodynamic length
formalism, and demonstrate the utility of this metric by solving for optimal
control parameter protocols in a simple nonequilibrium model.Comment: 5 page
Linear and nonlinear magneto-optical diffraction from one-dimensional periodic structures
Nonlinear magneto-optical diffraction from periodically structured samples has been studied using magnetization-induced second harmonic generation (MSHG). Several orders of diffraction were clearly observable in MSHG, along with a strong dependence on the magnetization. Sizeable asymmetry between the MSHG signal measured in positive and negative diffraction peaks, especially visible in second order, are explained by Fresnel factors. It was found that first-order diffraction hysteresis loops differ from all others by showing an ''overshoot'' at magnetization reversal, both in MSHG and in the linear magneto-optical Kerr effect. Tentatively this behavior is explained as due to inhomogeneous reversal of the magnetization in the stripes
Potential Models for Radiative Rare B Decays
We compute the branching ratios for the radiative rare decays of B into
K-Meson states and compare them to the experimentally determined branching
ratio for inclusive decay b -> s gamma using non relativistic quark model, and
form factor definitions consistent with HQET covariant trace formalism. Such
calculations necessarily involve a potential model. In order to test the
sensitivity of calculations to potential models we have used three different
potentials, namely linear potential, screening confining potential and heavy
quark potential as it stands in QCD.We find the branching ratios relative to
the inclusive b ->s gamma decay to be (16.07\pm 5.2)% for B -> K^* (892)gamma
and (7.25\pm 3.2)% for B -> K_2^* (1430)gamma for linear potential. In the case
of the screening confining potential these values are (19.75\pm 5.3)% and
(4.74\pm 1.2)% while those for the heavy quark potential are (11.18\pm 4.6)%
and (5.09\pm 2.7)% respectively. All these values are consistent with the
corresponding present CLEO experimental values: (16.25\pm 1.21)% and (5.93\pm
0.46)%.Comment: RevTeX, 6 pages, 1 eps figur
Charm and Bottom Semileptonic Decays
We review the present status of theoretical attempts to calculate the
semileptonic charm and bottom decays and then present a calculation of these
decays in the light--front frame at the kinematic point . This allows us
to evaluate the form factors at the same value of , even though the
allowed kinematic ranges for charm and bottom decays are very different. Also,
at this kinematic point the decay is given in terms of only one form factor
. For the ratio of the decay rates given by the E653 collaboration we
show that the determination of the ratio of the Cabibbo--Kobayashi--Maskawa
(CKM) matrix elements is consistent with that obtained from the unitarity
constraint. At present, though, the unitarity method still has greater
accuracy. Since comparisons of the semileptonic decays into and either
electrons or muons will be available soon from the E791 Fermilab experiment, we
also look at the massive muon case. We show that for a range of the
symmetry breaking is small even though the contributions of the
various helicity amplitudes becomes more complicated. For decays, the decay
at involves an extra form factor
coming from the photon contribution and so is not amenable to the same kind of
analysis, leaving only the decay as a
possibility. As the mass of the decaying particle increases we note that the
symmetry becomes badly broken at .Comment: Latex, 19 pages, two figures are attached, a minor change in the
manuscript related to thi
B -> K^* gamma from D -> K^* l nu
The B -> K^* gamma branching fraction is predicted using heavy quark spin
symmetry at large recoil to relate the tensor and (axial-)vector form factors,
using heavy quark flavor symmetry to relate the B decay form factors to the
measured D -> K^* l nu form form factors, and extrapolating the semileptonic B
decay form factors to large recoil assuming nearest pole dominance. This
prediction agrees with data surprisingly well, and we comment on its
implications for the extraction of |Vub| from B -> rho l nu.Comment: 10 page
Boarfish Acoustic Survey Cruise Report 10 July – 31 July, 2013
Use the URI link below to search the Marine Institute Data Discovery Catalogue for datasets relevant to this report.From the early 1970s the abundance of boarfish (Capros aper) was seen to increase
exponentially and distribution spread increasingly northwards along the western seaboard and Bay of Biscay (Blanchard and Vandermeirsch, 2005). This survey represents the third dedicated research survey for boarfish in the time series. The commercial fishing vessel MFV Felucca (as in 2011), an active participant in the fishery, was equipped with a calibrated scientific echosounder (Simrad EK 60) and transducer within a towed body. Data from this survey, in addition to the extensive biological research carried out on this species, forms part of a larger program aimed at increasing the knowledge of this species and its abundance outside of the commercial fishery. Data from this survey will be presented for
inclusion into the ICES Planning Group meeting for International Pelagic Surveys in January 2014 (WGIPS) and for the ICES assessment Working Group for Widely Distributed Stocks (WGWIDE) meeting in August 2013
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