2,807 research outputs found
Five-loop \sqrt\epsilon-expansions for random Ising model and marginal spin dimensionality for cubic systems
The \sqrt\epsilon-expansions for critical exponents of the weakly-disordered
Ising model are calculated up to the five-loop order and found to possess
coefficients with irregular signs and values. The estimate n_c = 2.855 for the
marginal spin dimensionality of the cubic model is obtained by the Pade-Borel
resummation of corresponding five-loop \epsilon-expansion.Comment: 9 pages, TeX, no figure
Cancer experience in the relatives of an unselected series of breast cancer patients
First- and second-degree relatives of an unselected series of 402 breast cancer patients have been studied for their cancer experience. In the first-degree relatives an excess of all cancers is seen [overall relative risk (RR) = 1.28, P = 0.002; males RR = 1.26, P = 0.047; females RR = 1.30, P = 0.022). There is a marked excess of sarcoma (RR = 4.26, P = 0.0064); females are at high risk of breast cancer (RR = 2.68, P < 0.0001) and males have an excess of carcinoma of the lip, oral cavity and pharynx (RR = 4.22, P = 0.0032). Second-degree relatives have a non-significant excess of all cancers (RR = 1.14, P = 0.14); females have a borderline excess of breast cancer (RR = 1.53, P = 0.08) and an excess of carcinoma of the kidney (RR = 7.46, P = 0.0012) and males have an excess of carcinoma of the trachea and lung (RR = 1.50, P = 0.032). No excess of prostate or ovarian carcinoma was seen. Relatives are at slightly higher risk if the index patient is diagnosed between the ages of 40 and 49 (first-degree RR = 1.64, P = 0.007; second-degree RR = 1.43, P = 0.02). The excess of cancers, including breast cancers, is not limited to a few high-risk families, but appears to be spread across many. These observations may be accounted for by shared environmental factors within families or a common predisposing gene with low penetrance
Interactions between fibroblastic reticular cells and B cells promote mesenteric lymph node lymphangiogenesis.
Lymphatic growth (lymphangiogenesis) within lymph nodes functions to promote dendritic cell entry and effector lymphocyte egress in response to infection or inflammation. Here we demonstrate a crucial role for lymphotoxin-beta receptor (LTβR) signaling to fibroblastic reticular cells (FRCs) by lymphotoxin-expressing B cells in driving mesenteric lymph node lymphangiogenesis following helminth infection. LTβR ligation on fibroblastic reticular cells leads to the production of B-cell-activating factor (BAFF), which synergized with interleukin-4 (IL-4) to promote the production of the lymphangiogenic factors, vascular endothelial growth factors (VEGF)-A and VEGF-C, by B cells. In addition, the BAFF-IL-4 synergy augments expression of lymphotoxin by antigen-activated B cells, promoting further B cell-fibroblastic reticular cell interactions. These results underlie the importance of lymphotoxin-dependent B cell-FRC cross talk in driving the expansion of lymphatic networks that function to promote and maintain immune responsiveness.The growth of lymph nodes in response to infection requires lymphangiogenesis. Dubey et al. show that the mesenteric lymph node lymphangiogenesis upon helminth infection depends on the signaling loop between the B and fibroblastic reticular cells (FRCs), whereby the FRCs respond to lymphotoxin secreted by B cells by releasing B cell activating factor
Demonstrating frequency-dependent transmission of sarcoptic mange in red foxes
Understanding the relationship between disease transmission and host density is essential for predicting disease spread and control. Using long-term data on sarcoptic mange in a red fox Vulpes vulpes population, we tested long-held assumptions of density- and frequency-dependent direct disease transmission. We also assessed the role of indirect transmission. Contrary to assumptions typical of epidemiological models, mange dynamics are better explained by frequency-dependent disease transmission than by density-dependent transmission in this canid. We found no support for indirect transmission. We present the first estimates of R0 and age-specific transmission coefficients for mange in foxes. These parameters are important for managing this poorly understood but highly contagious and economically damaging disease
Multimorbidity is common among young workers and related to increased work absenteeism and presenteeism: results from the population–based Raine Study cohort
Objectives This study aimed to determine the extent of both multimorbidity and work productivity loss among young adults with paid work and to analyze their association.
Methods We included 604 participants from a follow-up of the Raine Study that comprised a cohort who were 22 years at the time (Gen2-22). Information on 36 health conditions, grouped into 10 condition categories, was collected through questionnaires and physical assessments (for body mass index only). Quarterly questionnaires about work productivity, including total absenteeism, sickness absenteeism, and total presenteeism, were distributed electronically over the subsequent 12 months. Descriptive statistics were used to determine the prevalence of health conditions, condition categories, multimorbidity, and work productivity. Zero-inflated negative binomial regression analyses were used to assess the association of multimorbidity with productivity loss.
Results Multimorbidity prevalence was substantially higher in females (63%) compared to males (41%). Productivity loss increased as the number of condition categories increased. For example, total absenteeism was associated with an increase in the number of health condition categories in males [incidence rate ratio (IRR) 1.20, 95% confidence interval (CI) 1.05–1.36] and females (IRR 1.13, 95% CI 1.04–1.24). Similar results were found for sickness absenteeism and presenteeism. The highest burden of productivity loss was found for musculoskeletal disorders (42 444 hours/1000 workers/year), sleep problems (33 581 hours/1000 workers/year), mental and neurological conditions (15 650 hours/1000 workers/year), and ‘other’ medical conditions (22 519 hours/1000 workers/year).
Conclusions Multimorbidity appears to be highly prevalent among young adults with paid work and is strongly related to work productivity loss. Therefore, young workers should be targeted in interventions aiming to reduce multimorbidity and its impact on work productivity
Making High T Higher: A Theoretical Proposal
There is considerable evidence that the highest obtainable in a
copper-oxide plane is limitted by the competition between two effects: On the
one hand, as the concentration of doped-holes, , is increased, the pairing
scale, which is related to the properties of a doped Mott insulator, decreases.
On the otherhand, the superfluid density, which controls the stiffness of the
system to phase fluctuations, vanishes as , and increases with
increasing . Optimal is obtained at a crossover from a phase ordering
dominated regime at small to a pairing dominated regime at large . If
this description is valid, then higher 's can be obtained in an array of
coupled planes with different doped hole concentrations, such that a high
pairing scale is derived from the underdoped planes and a large phase stiffness
from the optimally or overdoped ones.Comment: 6 page
Rotational and Vibrational Dynamics of Interstitial Molecular Hydrogen
The calculation of the hindered roton-phonon energy levels of a hydrogen
molecule in a confining potential with different symmetries is systematized for
the case when the rotational angular momentum is a good quantum number. One
goal of this program is to interpret the energy-resolved neutron time of flight
spectrum previously obtained for HC. This spectrum gives direct
information on the energy level spectrum of H molecules confined to the
octahedral interstitial sites of solid C. We treat this problem of
coupled translational and orientational degrees of freedom a) by construction
of an effective Hamiltonian to describe the splitting of the manifold of states
characterized by a given value of and having a fixed total number of phonon
excitations, b) by numerical solutions of the coupled translation-rotation
problem on a discrete mesh of points in position space, and c) by a group
theoretical symmetry analysis. Results obtained from these three different
approaches are mutually consistent. The results of our calculations explain
several hitherto uninterpreted aspects of the experimental observations, but
show that a truly satisfactory orientational potential for the interaction of
an H molecule with a surrounding array of C atoms has not yet been
developed.Comment: 53 pages, 9 figures, to appear in Phys. Rev B (in press). Phys. Rev.
B (in press
Hubbard model versus t-J model: The one-particle spectrum
The origin of the apparent discrepancies between the one-particle spectra of
the Hubbard and t-J models is revealed: Wavefunction corrections, in addition
to the three-site terms, should supplement the bare t-J. In this way a
quantitative agreement between the two models is obtained, even for the
intermediate- values appropriate for the high-Tc cuprate superconductors.
Numerical results for clusters of up to 20 sites are presented. The momentum
dependence of the observed intensities in the photoemission spectra of
Sr2CuO2Cl2 are well described by this complete strong-coupling approach.Comment: 4 two-column RevTeX pages, including 4 Postscript figures. Uses epsf.
Accepted for publication in Physical Review B, Rapid Communicatio
Parton rescattering and screening in Au+Au collisions at RHIC
We study the microscopic dynamics of quarks and gluons in relativistic heavy
ion collisions in the framework of the Parton Cascade Model. We use lowest
order perturbative QCD cross sections with fixed lower momentum cutoff p_0. We
calculate the time-evolution of the Debye-screening mass for Au+Au collisions
at sqrt(s)=200 GeV per nucleon pair. The screening mass is used to determine a
lower limit for the allowed range of p_0. We also determine the energy density
reached through hard and semi-hard processes at RHIC, obtain a lower bound for
the rapidity density of charged hadrons produced by semihard interactions, and
analyze the extent of perturbative rescattering among partons.Comment: 6 pages, 4 figures, uses RevTeX 4.0; revised version with minor
corrections and one updated figur
- …