10,275 research outputs found
SUSY dark matter(s)
We review here the status of different dark matter candidates in the context
of supersymmetric models, in particular the neutralino as a realization of the
WIMP-mechanism and the gravitino. We give a summary of the recent bounds in
direct and indirect detection and also of the LHC searches relevant for the
dark matter question. We discuss also the implications of the Higgs discovery
for the supersymmetric dark matter models and give the prospects for the future
years.Comment: 16 pages, 3 figure
Hepatitis B among Pacific Islanders in Southern California: how is health information associated with screening and vaccination?
We measured Hepatitis B virus (HBV) transmission knowledge and self-reported screening/testing behavior among Pacific Islanders (Guamanians/Chamorros, Samoans, and Tongans) in Southern California. We also examined access and trust by Pacific Islanders of varying health information sources. We administered and analyzed survey data (N = 297), using a convenience sample in Los Angeles, Orange, and San Diego Counties in spring 2009. We found that while Pacific Islander respondents reported that they receive health information from physicians, and largely trust this source, information from and trust in physicians were not statistically significant in explaining whether respondents sought HBV screening or vaccination
Hyperon semileptonic decays and quark spin content of the proton
We investigate the hyperon semileptonic decays and the quark spin content of
the proton taking into account flavor SU(3) symmetry breaking.
Symmetry breaking is implemented with the help of the chiral quark-soliton
model in an approach, in which the dynamical parameters are fixed by the
experimental data for six hyperon semileptonic decay constants. As a result we
predict the unmeasured decay constants, particularly for ,
which will be soon measured and examine the effect of the SU(3) symmetry
breaking on the spin content of the proton. Unfortunately
large experimental errors of decays propagate in our analysis making
and practically undetermined. We conclude that
statements concerning the values of these two quantities, which are based on
the exact SU(3) symmetry, are premature. We stress that the meaningful results
can be obtained only if the experimental errors for the decays are
reduced.Comment: The final version accepted for publication in Phys. Rev. D. 18 pages,
RevTex is used with 4 figures include
Intrinsic decoherence and classical-quantum correspondence in two coupled delta-kicked rotors
We show that classical-quantum correspondence of center of mass motion in two
coupled delta-kicked rotors can be obtained from intrinsic decoherence of the
system itself which occurs due to the entanglement of the center of mass motion
to the internal degree of freedom without coupling to external environment
Progress on catastrophic health spending in 133 countries: a retrospective observational study
Background The goal of universal health coverage (UHC) requires inter alia that families who get needed health care do not suffer undue financial hardship as a result. This can be measured by the percentage of people in households whose out-of-pocket health expenditures are large relative to their income or consumption. We aimed to estimate the global incidence of catastrophic health spending, trends between 2000 and 2010, and associations between catastrophic health spending and macroeconomic and health system variables at the country level. Methods We did a retrospective observational study of health spending using data obtained from household surveys. Of 1566 potentially suitable household surveys, 553 passed quality checks, covering 133 countries between 1984 and 2015. We defined health spending as catastrophic when it exceeded 10% or 25% of household consumption. We estimated global incidence by aggregating up from every country, using a survey for the year in question when available, and interpolation and model-based estimates otherwise. We used multiple regression to explore the relation between a country’s incidence of catastrophic spending and gross domestic product (GDP) per person, the Gini coefficient for income inequality, and the share of total health expenditure spent by social security funds, other government agencies, private insurance schemes, and non-profit institutions. Findings The global incidence of catastrophic spending at the 10% threshold was estimated as 9·7% in 2000, 11·4% in 2005, and 11·7% in 2010. Globally, 808 million people in 2010 incurred catastrophic health spending. Across 94 countries with two or more survey datapoints, the population-weighted median annual rate of change of catastrophic payment incidence was positive whatever catastrophic payment incidence measure was used. Incidence of catastrophic payments was correlated positively with GDP per person and the share of GDP spent on health, and incidence correlated negatively with the share of total health spending channelled through social security funds and other government agencies. Interpretation The proportion of the population that is supposed to be covered by health insurance schemes or by national or subnational health services is a poor indicator of financial protection. Increasing the share of GDP spent on health is not sufficient to reduce catastrophic payment incidence; rather, what is required is increasing the share of total health expenditure that is prepaid, particularly through taxes and mandatory contributions
Progress on catastrophic health spending in 133 countries: a retrospective observational study
Background The goal of universal health coverage (UHC) requires inter alia that families who get needed health care do not suffer undue financial hardship as a result. This can be measured by the percentage of people in households whose out-of-pocket health expenditures are large relative to their income or consumption. We aimed to estimate the global incidence of catastrophic health spending, trends between 2000 and 2010, and associations between catastrophic health spending and macroeconomic and health system variables at the country level. Methods We did a retrospective observational study of health spending using data obtained from household surveys. Of 1566 potentially suitable household surveys, 553 passed quality checks, covering 133 countries between 1984 and 2015. We defined health spending as catastrophic when it exceeded 10% or 25% of household consumption. We estimated global incidence by aggregating up from every country, using a survey for the year in question when available, and interpolation and model-based estimates otherwise. We used multiple regression to explore the relation between a country’s incidence of catastrophic spending and gross domestic product (GDP) per person, the Gini coefficient for income inequality, and the share of total health expenditure spent by social security funds, other government agencies, private insurance schemes, and non-profit institutions. Findings The global incidence of catastrophic spending at the 10% threshold was estimated as 9·7% in 2000, 11·4% in 2005, and 11·7% in 2010. Globally, 808 million people in 2010 incurred catastrophic health spending. Across 94 countries with two or more survey datapoints, the population-weighted median annual rate of change of catastrophic payment incidence was positive whatever catastrophic payment incidence measure was used. Incidence of catastrophic payments was correlated positively with GDP per person and the share of GDP spent on health, and incidence correlated negatively with the share of total health spending channelled through social security funds and other government agencies. Interpretation The proportion of the population that is supposed to be covered by health insurance schemes or by national or subnational health services is a poor indicator of financial protection. Increasing the share of GDP spent on health is not sufficient to reduce catastrophic payment incidence; rather, what is required is increasing the share of total health expenditure that is prepaid, particularly through taxes and mandatory contributions
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A shared neural ensemble links distinct contextual memories encoded close in time.
Recent studies suggest that a shared neural ensemble may link distinct memories encoded close in time. According to the memory allocation hypothesis, learning triggers a temporary increase in neuronal excitability that biases the representation of a subsequent memory to the neuronal ensemble encoding the first memory, such that recall of one memory increases the likelihood of recalling the other memory. Here we show in mice that the overlap between the hippocampal CA1 ensembles activated by two distinct contexts acquired within a day is higher than when they are separated by a week. Several findings indicate that this overlap of neuronal ensembles links two contextual memories. First, fear paired with one context is transferred to a neutral context when the two contexts are acquired within a day but not across a week. Second, the first memory strengthens the second memory within a day but not across a week. Older mice, known to have lower CA1 excitability, do not show the overlap between ensembles, the transfer of fear between contexts, or the strengthening of the second memory. Finally, in aged mice, increasing cellular excitability and activating a common ensemble of CA1 neurons during two distinct context exposures rescued the deficit in linking memories. Taken together, these findings demonstrate that contextual memories encoded close in time are linked by directing storage into overlapping ensembles. Alteration of these processes by ageing could affect the temporal structure of memories, thus impairing efficient recall of related information
The Luminosity-Metallicity Relation of distant luminous infrared galaxies
One hundred and five 15mu selected objects in three ISO deep survey fields
(CFRS 3h, UDSR and UDSF) are studied on the basis of the high quality optical
spectra with resolution R>1000 from VLT/FORS2. Ninety two objects (88%) have
secure redshifts, ranging from 0 to 1.16 with a median value of 0.587.
Considerable care is taken in estimating the extinction property of individual
galaxy, which can seriously affect diagnostic diagrams and estimates of star
formation rates and of metal abundances. Two independent methods have been
adopted to estimate extinction, e.g. Balmer line ratio (A_V(Balmer)) and energy
balance between IR and Hbeta luminosities (A_V(IR)). For most of the z>0.4
luminous IR galaxies (LIRGs), the two extinction coefficients are consistent
well, with median values of A_V(IR) = 2.36. These distant LIRGs show many
properties strikingly in common with those of local (IRAS) LIRGs studied by
Veilleux et al. (1995). Our sample can provide a good representation of LIRGs
in the distant Universe. Most (>77%) ISO 15mu selected sample galaxies are
dominated by star formation. Oxygen abundances (12+log(O/H), derived from R23
and O32) in ISM in the distant LIRGs range from 8.36 to 8.93 with a median
value of 8.67. Distant LIRGs present a metal content less than half of that of
the local bright disks (i.e. L*). The Pegase2 models predict that total masses
(gas + stars) of the distant LIRGs are from 10^{11} Msun to <=10^{12} Msun. A
significant fraction of distant large disks are indeed LIRGs. Such massive
disks could have formed ~50% of their metals and stellar masses since z~1.Comment: 20 pages, 9 PS figures, Accepted for publication in A&
Evidence for SU(3) symmetry breaking from hyperon production
We examine the SU(3) symmetry breaking in hyperon semileptonic decays (HSD)
by considering two typical sets of quark contributions to the spin content of
the octet baryons: Set-1 with SU(3) flavor symmetry and Set-2 with SU(3) flavor
symmetry breaking in HSD. The quark distributions of the octet baryons are
calculated with a successful statistical model. Using an approximate relation
between the quark fragmentation functions and the quark distributions, we
predict polarizations of the octet baryons produced in annihilation
and semi-inclusive deeply lepton-nucleon scattering in order to reveal the
SU(3) symmetry breaking effect on the spin structure of the octet baryons. We
find that the SU(3) symmetry breaking significantly affects the hyperon
polarization. The available experimental data on the polarization
seem to favor the theoretical predictions with SU(3) symmetry breaking. We
conclude that there is a possibility to get a collateral evidence for SU(3)
symmetry breaking from hyperon production. The theoretical errors for our
predictions are discussed.Comment: 3 tables, 14 figure
Cluster pinch-point densities in polygons
In a statistical cluster or loop model such as percolation, or more generally
the Potts models or O(n) models, a pinch point is a single bulk point where
several distinct clusters or loops touch. In a polygon P harboring such a model
in its interior and with 2N sides exhibiting free/fixed side-alternating
boundary conditions, "boundary" clusters anchor to the fixed sides of P. At the
critical point and in the continuum limit, the density (i.e., frequency of
occurrence) of pinch-point events between s distinct boundary clusters at a
bulk point w in P is proportional to
_P. The
w_i are the vertices of P, psi_1^c is a conformal field theory (CFT) corner
one-leg operator, and Psi_s is a CFT bulk 2s-leg operator. In this article, we
use the Coulomb gas formalism to construct explicit contour integral formulas
for these correlation functions and thereby calculate the density of various
pinch-point configurations at arbitrary points in the rectangle, in the
hexagon, and for the case s=N, in the 2N-sided polygon at the system's critical
point. Explicit formulas for these results are given in terms of algebraic
functions or integrals of algebraic functions, particularly Lauricella
functions. In critical percolation, the result for s=N=2 gives the density of
red bonds between boundary clusters (in the continuum limit) inside a
rectangle. We compare our results with high-precision simulations of critical
percolation and Ising FK clusters in a rectangle of aspect ratio two and in a
regular hexagon and find very good agreement.Comment: 31 pages, 1 appendix, 21 figures. In the second version of this
article, we have improved the organization, figures, and references that
appeared in the first versio
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