6,155 research outputs found
Vulvar cancer in high-income countries: Increasing burden of disease
The aim of this study was to assess trends in the age-specific incidence of vulvar cancer in 13 high-income countries satisfying a priori conditions regarding the availability of cancer registry data over a 20-year period; these were Canada, the United States, nine European countries, Australia and Japan. Five-yearly incidence and population at risk were obtained from the International Agency for Research on Cancer's Cancer Incidence in Five Continents for the years 1988-1992 (Volume 7) to 2003-2007 (Volume 10). The 5-yearly average percent change (AvPC) over the period and standardised rate ratios (SRRs) for 2003-2007 versus 1988-1992 were used to assess changes in the age-standardised incidence rates of vulvar cancer for all ages, and for <60 years and 60+ years. During the study period, the 5-yearly AvPC across the 13 countries increased by 4.6% (p = 0.005) in women of all ages, and 11.6% (p = 0.02) in those <60 years. No change was observed in women aged 60+ years (5-yearly AvPC = 0.1%, p = 0.94). The SRR for 2003-2007 versus 1988-1992 was significantly elevated in women <60 years of age (SRR = 1.38, 95% CI: 1.30-1.46), but not in women of 60+ years (SRR = 1.01, 95% CI: 0.97-1.05). The increase in incidence in women <60 years of age drove a significant increase in the overall SRR in women of all ages (SRR = 1.14, 95% CI: 1.11-1.18). Some differences in the specific findings at the individual country level were observed. The findings are consistent with changing sexual behaviours and increasing levels of exposure to human papillomavirus (HPV) in cohorts born around/after about 1950, but younger cohorts offered HPV vaccination are likely to receive some protection against developing vulvar cancer in the future
Entropy and information in neural spike trains: Progress on the sampling problem
The major problem in information theoretic analysis of neural responses and
other biological data is the reliable estimation of entropy--like quantities
from small samples. We apply a recently introduced Bayesian entropy estimator
to synthetic data inspired by experiments, and to real experimental spike
trains. The estimator performs admirably even very deep in the undersampled
regime, where other techniques fail. This opens new possibilities for the
information theoretic analysis of experiments, and may be of general interest
as an example of learning from limited data.Comment: 7 pages, 4 figures; referee suggested changes, accepted versio
From non-symmetric particle systems to non-linear PDEs on fractals
We present new results and challenges in obtaining hydrodynamic limits for
non-symmetric (weakly asymmetric) particle systems (exclusion processes on
pre-fractal graphs) converging to a non-linear heat equation. We discuss a
joint density-current law of large numbers and a corresponding large deviations
principle.Comment: v2: 10 pages, 1 figure. To appear in the proceedings for the 2016
conference "Stochastic Partial Differential Equations & Related Fields" in
honor of Michael R\"ockner's 60th birthday, Bielefel
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Complete Experimental Structure Determination of the p(3x2)pg Phase of Glycine on Cu{110}
We present a quantitative low energy electron diffraction (LEED) surface-crystallograpic
study of the complete adsorption geometry of glycine adsorbed on Cu{110} in the ordered
p(3×2) phase. The glycine molecules form bonds to the surface through the N atoms of the
amino group and the two O atoms of the de-protonated carboxylate group, each with separate
Cu atoms such that every Cu atom in the first layer is involved in a bond. Laterally, N atoms are
nearest to the atop site (displacement 0.41 Å). The O atoms are asymmetrically displaced from
the atop site by 0.54 Å and 1.18 Å with two very different O-Cu bond lengths of 1.93 Å and
2.18 Å. The atom positions of the upper-most Cu layers show small relaxations within 0.07 Å
of the bulk-truncated surface geometry. The unit cell of the adsorbate layer consists of two
glycine molecules, which are related by a glide-line symmetry operation. This study clearly
shows that a significant coverage of adsorbate structures without this glide-line symmetry must
be rejected, both on the grounds of the energy dependence of the spot intensities (LEED-IV
curves) and of systematic absences in the LEED pattern
Revealing the Hidden Details of Nanostructure in a Pharmaceutical Cream
Creams are multi-component semi-solid emulsions that find widespread utility across a wide range of pharmaceutical, cosmetic, and personal care products, and they also feature prominently in veterinary preparations and processed foodstuffs. The internal architectures of these systems, however, have to date been inferred largely through macroscopic and/or indirect experimental observations and so they are not well-characterized at the molecular level. Moreover, while their long-term stability and shelf-life, and their aesthetics and functional utility are critically dependent upon their molecular structure, there is no real understanding yet of the structural mechanisms that underlie the potential destabilizing effects of additives like drugs, anti-oxidants or preservatives, and no structure-based rationale to guide product formulation. In the research reported here we sought to address these deficiencies, making particular use of small-angle neutron scattering and exploiting the device of H/D contrast variation, with complementary studies also performed using bright-field and polarised light microscopy, small-angle and wide-angle X-ray scattering, and steady-state shear rheology measurements. Through the convolved findings from these studies we have secured a finely detailed picture of the molecular structure of creams based on Aqueous Cream BP, and our findings reveal that the structure is quite different from the generic picture of cream structure that is widely accepted and reproduced in textbooks
The Significant Digit Law in Statistical Physics
The occurrence of the nonzero leftmost digit, i.e., 1, 2, ..., 9, of numbers
from many real world sources is not uniformly distributed as one might naively
expect, but instead, the nature favors smaller ones according to a logarithmic
distribution, named Benford's law. We investigate three kinds of widely used
physical statistics, i.e., the Boltzmann-Gibbs (BG) distribution, the
Fermi-Dirac (FD) distribution, and the Bose-Einstein (BE) distribution, and
find that the BG and FD distributions both fluctuate slightly in a periodic
manner around the Benford distribution with respect to the temperature of the
system, while the BE distribution conforms to it exactly whatever the
temperature is. Thus the Benford's law seems to present a general pattern for
physical statistics and might be even more fundamental and profound in nature.
Furthermore, various elegant properties of Benford's law, especially the
mantissa distribution of data sets, are discussed.Comment: 21 latex pages, 5 figures, final version in journal publicatio
Neural Decision Boundaries for Maximal Information Transmission
We consider here how to separate multidimensional signals into two
categories, such that the binary decision transmits the maximum possible
information transmitted about those signals. Our motivation comes from the
nervous system, where neurons process multidimensional signals into a binary
sequence of responses (spikes). In a small noise limit, we derive a general
equation for the decision boundary that locally relates its curvature to the
probability distribution of inputs. We show that for Gaussian inputs the
optimal boundaries are planar, but for non-Gaussian inputs the curvature is
nonzero. As an example, we consider exponentially distributed inputs, which are
known to approximate a variety of signals from natural environment.Comment: 5 pages, 3 figure
Concealed concern: Fathers' experience of having a child with Juvenile Idiopathic Arthritis
Despite increased research into families of chronically ill children, more needs to be known about the father’s experience. We address this issue through asking: ‘What is it like to be the father of a child with juvenile idiopathic arthritis?’ (JIA). Four members of eight families with an adolescent diagnosed with JIA, including seven fathers, were interviewed and transcripts analyzed using grounded theory. This study suggests that fathers of children with JIA experience several severe losses which are exacerbated through comparisons they make between their own situation and that of fathers of healthy children. In addition, the fathers faced several constraints which reduced their opportunities to communicate with their ill child through shared activities. Fathers appeared to conceal their distress by adopting strategies of denial and distraction however their adjustment was facilitated, to some extent, by social support. They could also develop greater acceptance of their situation over time as the care of their ill child became assimilated into family life and constraints upon their life gradually reduced through the increased maturity of their son or daughter with JIA. These findings have implications for healthcare professionals and voluntary organizations
The CPTPP trade deal is a major threat to public health and warrants a health impact assessment.
The UK’s decision to join one of the world’s largest free trade agreements has implications for health that need urgent assessment, argue Courtney McNamara and colleague
The role of input noise in transcriptional regulation
Even under constant external conditions, the expression levels of genes
fluctuate. Much emphasis has been placed on the components of this noise that
are due to randomness in transcription and translation; here we analyze the
role of noise associated with the inputs to transcriptional regulation, the
random arrival and binding of transcription factors to their target sites along
the genome. This noise sets a fundamental physical limit to the reliability of
genetic control, and has clear signatures, but we show that these are easily
obscured by experimental limitations and even by conventional methods for
plotting the variance vs. mean expression level. We argue that simple, global
models of noise dominated by transcription and translation are inconsistent
with the embedding of gene expression in a network of regulatory interactions.
Analysis of recent experiments on transcriptional control in the early
Drosophila embryo shows that these results are quantitatively consistent with
the predicted signatures of input noise, and we discuss the experiments needed
to test the importance of input noise more generally.Comment: 11 pages, 5 figures minor correction
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