1,629 research outputs found
Contemporary Occupational Carcinogen Exposure and Bladder Cancer: A Systematic Review and Meta-analysis
Importance: Bladder cancer (BC) is a common disease. Despite manufacturing and legislative changes to workplace hygiene, many BCs still arise through occupational carcinogen exposure.
Objective: To profile contemporary risks of occupational BC.
Data Sources: A systematic review using PubMed, Medline, Embase, and Web of Science was performed in October 2012 (initial review) and May 2014 (final review) and was updated in June 2015.
Study Selection: We identified 263 eligible articles. We excluded reports in which BC or occupation were not the main focus, and those with insufficient case, risk, or confidence interval data. We selected the most recent data from populations with multiple reports.
Data Extraction and Synthesis: Reports were selected by 2 of us independently. We combined odds ratios and risk ratios (RRs) to provide pooled RRs, using maximally adjusted RRs in a random effects model. Heterogeneity and publication bias were assessed using I2 and Begg and Egger tests. Risk estimates were annotated by occupational class using Nordisk Yrkesklassificering, or Nordic Occupational Classification, and International Standard Classifications of Occupations (NYK and ISCO-1958) Codes.
Main Outcomes and Measures: Occupations were profiled by BC incidence and mortality risk over time. After data collection, we detected a sex difference in these profiles and recorded this as a secondary outcome.
Results: Meta-analysis revealed increased BC incidence in 42 of 61 occupational classes and increased BC-specific mortality in 16 of 40 occupational classes. Reduced incidence and mortality were seen in 6 of 61 and 2 of 40 classes, respectively. Risk varied with sex and was greatest in men (standardized incidence ratio, 1.03 [95% CI, 1.02-1.03]; P < .001]). From the 1960s to the 1980s, there was a steady decline in standarized incidence ratio (SIR) for both sexes. This trend reversed from the 1980s, as in the decade 2000 to 2010 the SIR increased to 1.13 (95% CI, 1.07-1.19) for men and 1.27 (95% CI, 1.12-1.43) for women. In contrast, mortality risk declined for both sexes from the 1960s to the 1990s. The overall risk of BC mortality was also greater for men (standardized mortality ratio [SMR], 1.32 [95% CI, 1.18-1.48]) than for women (SMR, 1.14 [95% CI, 0.80-1.63]). Limitations include possible publication bias, that reports stratify workers mostly by job title not task, that not all studies adjusted for smoking, and that the population was mostly derived from Western nations.
Conclusions and Relevance: The profile of contemporary occupations with increased BC risk is broad and differs for incidence and mortality. Currently the incidence seems to be increasing, and this increase is occurring faster in women than men. Improved detection mechanisms and screening are possible reasons for this. Workers with aromatic amine exposure have the highest incidence, while those exposed to polycyclic aromatic hydrocarbons and heavy metals have the greatest mortality
Phase diagram of the one-dimensional extended attractive Hubbard model for large nearest-neighbor repulsion
We consider the extended Hubbard model with attractive on-site interaction U
and nearest-neighbor repulsions V. We construct an effective Hamiltonian
H_{eff} for hopping t<<V and arbitrary U<0. Retaining the most important terms,
H_{eff} can be mapped onto two XXZ models, solved by the Bethe ansatz. The
quantum phase diagram shows two Luttinger liquid phases and a region of phase
separation between them. For density n<0.422 and U<-4, singlet superconducting
correlations dominate at large distances. For some parameters, the results are
in qualitative agreement with experiments in BaKBiO.Comment: 6 pages, 3 figures, submitted to Phys. Rev.
Securing Water, Sustaining Growth: Report of the GWP/OECD Task Force on Water Security and Sustainable Growth
Peer Revie
Mirror Symmetry and Other Miracles in Superstring Theory
The dominance of string theory in the research landscape of quantum gravity
physics (despite any direct experimental evidence) can, I think, be justified
in a variety of ways. Here I focus on an argument from mathematical fertility,
broadly similar to Hilary Putnam's 'no miracles argument' that, I argue, many
string theorists in fact espouse. String theory leads to many surprising,
useful, and well-confirmed mathematical 'predictions' - here I focus on mirror
symmetry. These predictions are made on the basis of general physical
principles entering into string theory. The success of the mathematical
predictions are then seen as evidence for framework that generated them. I
attempt to defend this argument, but there are nonetheless some serious
objections to be faced. These objections can only be evaded at a high
(philosophical) price.Comment: For submission to a Foundations of Physics special issue on "Forty
Years Of String Theory: Reflecting On the Foundations" (edited by G. `t
Hooft, E. Verlinde, D. Dieks and S. de Haro)
Molecular scale contact line hydrodynamics of immiscible flows
From extensive molecular dynamics simulations on immiscible two-phase flows,
we find the relative slipping between the fluids and the solid wall everywhere
to follow the generalized Navier boundary condition, in which the amount of
slipping is proportional to the sum of tangential viscous stress and the
uncompensated Young stress. The latter arises from the deviation of the
fluid-fluid interface from its static configuration. We give a continuum
formulation of the immiscible flow hydrodynamics, comprising the generalized
Navier boundary condition, the Navier-Stokes equation, and the Cahn-Hilliard
interfacial free energy. Our hydrodynamic model yields interfacial and velocity
profiles matching those from the molecular dynamics simulations at the
molecular-scale vicinity of the contact line. In particular, the behavior at
high capillary numbers, leading to the breakup of the fluid-fluid interface, is
accurately predicted.Comment: 33 pages for text in preprint format, 10 pages for 10 figures with
captions, content changed in this resubmissio
YREC: The Yale Rotating Stellar Evolution Code
The stellar evolution code YREC is outlined with emphasis on its applications
to helio- and asteroseismology. The procedure for calculating calibrated solar
and stellar models is described. Other features of the code such as a non-local
treatment of convective core overshoot, and the implementation of a
parametrized description of turbulence in stellar models, are considered in
some detail. The code has been extensively used for other astrophysical
applications, some of which are briefly mentioned at the end of the paper.Comment: 10 pages, 2 figures, ApSS accepte
Stellar evolution and modelling stars
In this chapter I give an overall description of the structure and evolution
of stars of different masses, and review the main ingredients included in
state-of-the-art calculations aiming at reproducing observational features. I
give particular emphasis to processes where large uncertainties still exist as
they have strong impact on stellar properties derived from large compilations
of tracks and isochrones, and are therefore of fundamental importance in many
fields of astrophysics.Comment: Lecture presented at the IVth Azores International Advanced School in
Space Sciences on "Asteroseismology and Exoplanets: Listening to the Stars
and Searching for New Worlds" (arXiv:1709.00645), which took place in Horta,
Azores Islands, Portugal in July 201
CLES, Code Liegeois d'Evolution Stellaire
Cles is an evolution code recently developed to produce stellar models
meeting the specific requirements of studies in asteroseismology. It offers the
users a lot of choices in the input physics they want in their models and its
versatility allows them to tailor the code to their needs and implement easily
new features. We describe the features implemented in the current version of
the code and the techniques used to solve the equations of stellar structure
and evolution. A brief account is given of the use of the program and of a
solar calibration realized with it.Comment: Comments: 8 pages, Astrophys. Space Sci. CoRoT-ESTA Volume, in the
pres
ASTEC -- the Aarhus STellar Evolution Code
The Aarhus code is the result of a long development, starting in 1974, and
still ongoing. A novel feature is the integration of the computation of
adiabatic oscillations for specified models as part of the code. It offers
substantial flexibility in terms of microphysics and has been carefully tested
for the computation of solar models. However, considerable development is still
required in the treatment of nuclear reactions, diffusion and convective
mixing.Comment: Astrophys. Space Sci, in the pres
Quantum Monte Carlo with Directed Loops
We introduce the concept of directed loops in stochastic series expansion and
path integral quantum Monte Carlo methods. Using the detailed balance rules for
directed loops, we show that it is possible to smoothly connect generally
applicable simulation schemes (in which it is necessary to include
back-tracking processes in the loop construction) to more restricted loop
algorithms that can be constructed only for a limited range of Hamiltonians
(where back-tracking can be avoided). The "algorithmic discontinuities" between
general and special points (or regions) in parameter space can hence be
eliminated. As a specific example, we consider the anisotropic S=1/2 Heisenberg
antiferromagnet in an external magnetic field. We show that directed loop
simulations are very efficient for the full range of magnetic fields (zero to
the saturation point) and anisotropies. In particular for weak fields and
anisotropies, the autocorrelations are significantly reduced relative to those
of previous approaches. The back-tracking probability vanishes continuously as
the isotropic Heisenberg point is approached. For the XY-model, we show that
back-tracking can be avoided for all fields extending up to the saturation
field. The method is hence particularly efficient in this case. We use directed
loop simulations to study the magnetization process in the 2D Heisenberg model
at very low temperatures. For LxL lattices with L up to 64, we utilize the
step-structure in the magnetization curve to extract gaps between different
spin sectors. Finite-size scaling of the gaps gives an accurate estimate of the
transverse susceptibility in the thermodynamic limit: chi_perp = 0.0659 +-
0.0002.Comment: v2: Revised and expanded discussion of detailed balance, error in
algorithmic phase diagram corrected, to appear in Phys. Rev.
- …
