586 research outputs found
Influence of Demographic Patterns on Human Response to Exposure to Environmental Contaminants: Heterogeneity Factors
It is generally accepted that the risk of disease and death vary markedly by age and sex. However, there are also inherited and acquired factors that cause vast differences in human susceptibility to many pollutant exposures. Most people are less familiar with this wide range of heterogeneity precipitated by genetic make-up, life style, occupation, nutrition, residence location, etc.
The combined role of these many heterogeneity factors is often underestimated. Yet they are the major factors that determine the evolution of mortality and morbidity patterns within a population.
In this paper, we examine a variety of heterogeneities present in environmental pollutant susceptibilities, briefly look at how attempts to recognize heterogeneity have played a role in efforts to regulate pollutants, consider how likely shifts in the composition of population may affect morbidity and mortality rates affected by environmental pollution, discuss how indirect heterogeneity factors can lead to additional complications in interpretations of pollution-related mortality statistics, and offer several suggestive models of heterogeneous susceptibility
Contour Maps of Demographic Surfaces
This paper presents a bouquet of contour maps to suggest the broad potential of their use in demographic studies. Every picture presented could serve as the basis for a thousand words or more of explanation and analysis, but here we merely serve up the maps as illustrations of the method. For an example of how such maps can be used in demographic analysis, see Caselli, Vaupel, and Yashin (1985): Mortality in Italy--Contours of a Century of Evolution (CP-85-24, International Institute for Applied Systems Analysis, Laxenburg, Austria)
Newborn patients exhibit an unusual pattern of interleukin 10 and interferon γ serum levels in response to cardiac surgery
AbstractObjective: The aim of this study was to determine the clinical significance of serum levels of interleukin 10 and interferon γ in pediatric patients undergoing cardiopulmonary bypass. Methods: We divided the patients into 2 groups: 8 neonates and 19 nonnewborn children. Interleukin 10 and interferon γ serum levels were quantified before sternotomy, at admission to the pediatric intensive care unit (30 minutes postoperatively), 24 hours after the onset of the operation, and 3 days after the operation. Results: Newborn patients displayed significantly greater amounts of serum interleukin 10 than older children, not only in regard to the peak level achieved but also at every postoperative time point analyzed. In contrast, no significant changes in interferon γ serum levels were observed in neonates at any time point, whereas nonnewborn pediatric patients showed a significant increase in interferon γ serum concentrations immediately after the operation. This unusual pattern of cytokine response in newborn patients was not associated with modifications in cortisol serum levels. Furthermore, although neonates had significantly different surgical and clinical variables than did the nonnewborn pediatric patients, the variation in interleukin 10 production in neonates could not be accounted for by differences in the magnitude of surgical injury. In the group of neonates, there were significant positive correlations between peak interleukin 10 serum levels and both partial pressure of arterial oxygen/fraction of inspired oxygen ratio and postoperative body weight gain. Conclusions: Newborn patients undergoing cardiopulmonary bypass exhibit a distinctive biologic response pattern characterized by high levels of serum interleukin 10 without changes in serum interferon γ. This cytokine imbalance could have potential clinical implications.J Thorac Cardiovasc Surg 2002;123:451-
Small BGK waves and nonlinear Landau damping
Consider 1D Vlasov-poisson system with a fixed ion background and periodic
condition on the space variable. First, we show that for general homogeneous
equilibria, within any small neighborhood in the Sobolev space W^{s,p}
(p>1,s<1+(1/p)) of the steady distribution function, there exist nontrivial
travelling wave solutions (BGK waves) with arbitrary minimal period and
traveling speed. This implies that nonlinear Landau damping is not true in
W^{s,p}(s<1+(1/p)) space for any homogeneous equilibria and any spatial period.
Indeed, in W^{s,p} (s<1+(1/p)) neighborhood of any homogeneous state, the long
time dynamics is very rich, including travelling BGK waves, unstable
homogeneous states and their possible invariant manifolds. Second, it is shown
that for homogeneous equilibria satisfying Penrose's linear stability
condition, there exist no nontrivial travelling BGK waves and unstable
homogeneous states in some W^{s,p} (p>1,s>1+(1/p)) neighborhood. Furthermore,
when p=2,we prove that there exist no nontrivial invariant structures in the
H^{s} (s>(3/2)) neighborhood of stable homogeneous states. These results
suggest the long time dynamics in the W^{s,p} (s>1+(1/p)) and particularly, in
the H^{s} (s>(3/2)) neighborhoods of a stable homogeneous state might be
relatively simple. We also demonstrate that linear damping holds for initial
perturbations in very rough spaces, for linearly stable homogeneous state. This
suggests that the contrasting dynamics in W^{s,p} spaces with the critical
power s=1+(1/p) is a trully nonlinear phenomena which can not be traced back to
the linear level
A step towards testing general relativity using weak gravitational lensing and redshift surveys
Using the linear theory of perturbations in General Relativity, we express a
set of consistency relations that can be observationally tested with current
and future large scale structure surveys. We then outline a stringent
model-independent program to test gravity on cosmological scales. We illustrate
the feasibility of such a program by jointly using several observables like
peculiar velocities, galaxy clustering and weak gravitational lensing. After
addressing possible observational or astrophysical caveats like galaxy bias and
redshift uncertainties, we forecast in particular how well one can predict the
lensing signal from a cosmic shear survey using an over-lapping galaxy survey.
We finally discuss the specific physics probed this way and illustrate how
gravity models would fail such a test.Comment: 12 pages, 10 figure
Mutual Events in the Cold Classical Transneptunian Binary System Sila and Nunam
Hubble Space Telescope observations between 2001 and 2010 resolved the binary
components of the Cold Classical transneptunian object (79360) Sila-Nunam
(provisionally designated 1997 CS29). From these observations we have
determined the circular, retrograde mutual orbit of Nunam relative to Sila with
a period of 12.50995 \pm 0.00036 days and a semimajor axis of 2777 \pm 19 km. A
multi-year season of mutual events, in which the two near-equal brightness
bodies alternate in passing in front of one another as seen from Earth, is in
progress right now, and on 2011 Feb. 1 UT, one such event was observed from two
different telescopes. The mutual event season offers a rich opportunity to
learn much more about this barely-resolvable binary system, potentially
including component sizes, colors, shapes, and albedo patterns. The low
eccentricity of the orbit and a photometric lightcurve that appears to coincide
with the orbital period are consistent with a system that is tidally locked and
synchronized, like the Pluto-Charon system. The orbital period and semimajor
axis imply a system mass of (10.84 \pm 0.22) \times 10^18 kg, which can be
combined with a size estimate based on Spitzer and Herschel thermal infrared
observations to infer an average bulk density of 0.72 +0.37 -0.23 g cm^-3,
comparable to the very low bulk densities estimated for small transneptunian
binaries of other dynamical classes.Comment: In press in Icaru
Notes on bordered Floer homology
This is a survey of bordered Heegaard Floer homology, an extension of the
Heegaard Floer invariant HF-hat to 3-manifolds with boundary. Emphasis is
placed on how bordered Heegaard Floer homology can be used for computations.Comment: 73 pages, 29 figures. Based on lectures at the Contact and Symplectic
Topology Summer School in Budapest, July 2012. v2: Fixed many small typo
Measurement of the Transverse-Longitudinal Cross Sections in the p (e,e'p)pi0 Reaction in the Delta Region
Accurate measurements of the p(e,e?p)pi0 reaction were performed at
Q^2=0.127(GeV/c)^2 in the Delta resonance energy region. The experiments at the
MIT-Bates Linear Accelerator used an 820 MeV polarized electron beam with the
out of plane magnetic spectrometer system (OOPS). In this paper we report the
first simultaneous determination of both the TL and TL? (``fifth" or polarized)
cross sections at low Q^{2} where the pion cloud contribution dominates the
quadrupole amplitudes (E2 and C2). The real and imaginary parts of the
transverse-longitudinal cross section provide both a sensitive determination of
the Coulomb quadrupole amplitude and a test of reaction calculations.
Comparisons with model calculations are presented. The empirical MAID
calculation gives the best overall agreement with this accurate data. The
parameters of this model for the values of the resonant multipoles are
|M_{1+}(I=3/2)|= (40.9 \pm 0.3)10^{-3}/m_pi, CMR= C2/M1= -6.5 \pm 0.3%,
EMR=E2/M1=-2.2 \pm 0.9%, where the errors are due to the experimental
uncertainties.Comment: 10 pages, 3 figures, minor corrections and addition
Tunneling of quantum rotobreathers
We analyze the quantum properties of a system consisting of two nonlinearly
coupled pendula. This non-integrable system exhibits two different symmetries:
a permutational symmetry (permutation of the pendula) and another one related
to the reversal of the total momentum of the system. Each of these symmetries
is responsible for the existence of two kinds of quasi-degenerated states. At
sufficiently high energy, pairs of symmetry-related states glue together to
form quadruplets. We show that, starting from the anti-continuous limit,
particular quadruplets allow us to construct quantum states whose properties
are very similar to those of classical rotobreathers. By diagonalizing
numerically the quantum Hamiltonian, we investigate their properties and show
that such states are able to store the main part of the total energy on one of
the pendula. Contrary to the classical situation, the coupling between pendula
necessarily introduces a periodic exchange of energy between them with a
frequency which is proportional to the energy splitting between
quasi-degenerated states related to the permutation symmetry. This splitting
may remain very small as the coupling strength increases and is a decreasing
function of the pair energy. The energy may be therefore stored in one pendulum
during a time period very long as compared to the inverse of the internal
rotobreather frequency.Comment: 20 pages, 11 figures, REVTeX4 styl
Model Checking and Co-simulation of a Dynamic Task Dispatcher Circuit using CADP
International audienceThe complexity of multiprocessor architectures for mobile multi-media applications renders their validation challenging. In addition, to provide the necessary flexibility, a part of the functionality is realized by software. Thus, a formal model has to take into account both hardware and software. In this paper we report on the use of LOTOS NT and CADP for the formal modeling and analysis of the DTD (Dynamic Task Dispatcher), a complex hardware block of an industrial hardware architecture developed by STMicroelectronics. Using LOTOS NT facilitated exploration of alternative design choices and increased the confidence in the DTD, by, on the one hand, automatic analysis of formal models easily understood by the architect of the DTD, and, on the other hand, co-simulation of the formal model with the implementation used for synthesis
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