1,326 research outputs found
Cross-National Comparisons of Socioeconomic Differences in Overweight and Obesity
Overweight and obesity have become increasingly common in the past decades. Overweight affects
30–80% of adults in Europe. The World Health Organization estimates that 150 million adults in
Europe will be obese by 2010. The associated costs with overweight, obesity and related diseases
are gargantuan, both from a societal and a financial point of view. One 2002 estimate indicated that
the total direct and indirect annual costs of obesity in 15 EU countries may have been as high as €
32.8 billion. Obesity and its associated risks may kill 320 000 men and women annually in Western
Europe. The effects on quality of life are more difficult to quantify but are manifold. This raises the
question what can be done about it, and how this can be done most effectively.
The immediate cause of obesity and overweight is an energy imbalance between calories
consumed on one hand, and calories expended on the other hand. But it is overly simplistic to regard
overweight and obesity as the result of an imbalance between energy intake and expenditure.
Biological susceptibility interacts with a changing environment that includes more sedentary
lifestyles and increased dietary abundance. The
Some asymptotic properties of duplication graphs
Duplication graphs are graphs that grow by duplication of existing vertices,
and are important models of biological networks, including protein-protein
interaction networks and gene regulatory networks. Three models of graph growth
are studied: pure duplication growth, and two two-parameter models in which
duplication forms one element of the growth dynamics. A power-law degree
distribution is found to emerge in all three models. However, the parameter
space of the latter two models is characterized by a range of parameter values
for which duplication is the predominant mechanism of graph growth. For
parameter values that lie in this ``duplication-dominated'' regime, it is shown
that the degree distribution either approaches zero asymptotically, or
approaches a non-zero power-law degree distribution very slowly. In either
case, the approach to the true asymptotic degree distribution is characterized
by a dependence of the scaling exponent on properties of the initial degree
distribution. It is therefore conjectured that duplication-dominated,
scale-free networks may contain identifiable remnants of their early structure.
This feature is inherited from the idealized model of pure duplication growth,
for which the exact finite-size degree distribution is found and its asymptotic
properties studied.Comment: 19 pages, including 3 figure
Probing metal ion binding and conformational properties of the colicin E9 endonuclease by electrospray ionization time-of-flight mass spectrometry
Nano-electrospray ionization time-of-flight mass spectrometry (ESI-MS) was used to study the conformational consequences of metal ion binding to the colicin E9 endonuclease (E9 DNase) by taking advantage of the unique capability of ESI-MS to allow simultaneous assessment of conformational heterogeneity and metal ion binding. Alterations of charge state distributions on metal ion binding/release were correlated with spectral changes observed in far- and near-UV circular dichroism (CD) and intrinsic tryptophan fluorescence. In addition, hydrogen/deuterium (H/D) exchange experiments were used to probe structural integrity. The present study shows that ESI-MS is sensitive to changes of the thermodynamic stability of E9 DNase as a result of metal ion binding/release in a manner consistent with that deduced from proteolysis and calorimetric experiments. Interestingly, acid-induced release of the metal ion from the E9 DNase causes dramatic conformational instability associated with a loss of fixed tertiary structure, but secondary structure is retained. Furthermore, ESI-MS enabled the direct observation of the noncovalent protein complex of E9 DNase bound to its cognate immunity protein Im9 in the presence and absence of Zn2+. Gas-phase dissociation experiments of the deuterium-labeled binary and ternary complexes revealed that metal ion binding, not Im9, results in a dramatic exchange protection of E9 DNase in the complex. In addition, our metal ion binding studies and gas-phase dissociation experiments of the ternary E9 DNase-Zn2+-Im9 complex have provided further evidence that electrostatic interactions govern the gas phase ion stability
Background Dependent Lorentz Violation: Natural Solutions to the Theoretical Challenges of the OPERA Experiment
To explain both the OPERA experiment and all the known phenomenological
constraints/observations on Lorentz violation, the Background Dependent Lorentz
Violation (BDLV) has been proposed. We study the BDLV in a model independent
way, and conjecture that there may exist a "Dream Special Relativity Theory",
where all the Standard Model (SM) particles can be subluminal due to the
background effects. Assuming that the Lorentz violation on the Earth is much
larger than those on the interstellar scale, we automatically escape all the
astrophysical constraints on Lorentz violation. For the BDLV from the effective
field theory, we present a simple model and discuss the possible solutions to
the theoretical challenges of the OPERA experiment such as the Bremsstrahlung
effects for muon neutrinos and the pion decays. Also, we address the Lorentz
violation constraints from the LEP and KamLAMD experiments. For the BDLV from
the Type IIB string theory with D3-branes and D7-branes, we point out that the
D3-branes are flavour blind, and all the SM particles are the conventional
particles as in the traditional SM when they do not interact with the
D3-branes. Thus, we not only can naturally avoid all the known phenomenological
constraints on Lorentz violation, but also can naturally explain all the
theoretical challenges. Interestingly, the energy dependent photon velocities
may be tested at the experiments.Comment: RevTex4, 14 pages, minor corrections, references adde
Axionic shortcuts for high energy photons
We study the photon axion mixing in the presence of large extra dimensions.
The eigenvalues and eigenstates of the mixing matrix are analyzed and we
establish the resonance condition for the total conversion of a high energy
photon into a Kaluza-Klein (KK) axion state. This resonant transition, a photon
transformed into a KK axion travelling freely through the bulk and converting
back into a photon, may provide a plausible explanation for the transparency of
the universe to energetic photons. If the brane we live in is curved, then
there are shortcuts through the bulk, which the axion can take. Within our
model, the photons having the appropriate resonance energy are using the
axionic shortcut and arrive earlier compared to the photons which follow the
geodesic on the brane. We suggest that such axionic shortcuts are at the root
of the dispersion of time arrival of photons observed by the MAGIC telescope.
We indicate also the cosmological significance of the existence of axionic
shortcuts for the photon.Comment: 7 page
High relapse-free survival after preoperative and intraoperative radiotherapy and resection for sulcus superior tumors
STUDY OBJECTIVES: Relapse-free survival in patients with sulcus superior
tumors. DESIGN: Prospective registration study. SETTING: Department of
surgical oncology of a university hospital. PATIENTS: Twenty-one patients
treated with preoperative radiotherapy (46 Gy), lobectomy and chest-wall
resection, and intraoperative radiotherapy (10 Gy). RESULTS: After a
median follow-up of 18 months, 18 patients (85%) were free from
locoregional relapse, while 8 patients were still alive. CONCLUSIONS: The
results show that this protocol can achieve excellent local tumor control
and can even be used for palliative treatment
Electromagnetic interference prediction in an in-house power-line
Abstract
—In this paper a new methodology for the prediction
of the conducted-emission propagation in an in-house power-
line network is presented. This methodology is based on the
modal
S
-parameter characterization of the devices present in the
power-line network, as well as on the modal modeling of branch-
line connections. The modal
S
parameters relate common- and
di
ff
erential-mode waves, and give more information regarding
interference propagation. With this methodology, common- and
di
ff
erential-mode attenuations, and modal conversion between
common and di
ff
erential modes can be accurately predicted,
which is of great interest for power-line communication devel-
opment and conducted-emission mitigation. This methodology is
tested by accurately predicting the interference levels up to 100
MHz of an in-house power-line network composed by thermal-
magnetic circuit breakers, residual-current circuit breakers,
single-phase wires and light bulbs.Peer ReviewedPostprint (author’s final draft
Low serum vitamin D is associated with axial length and risk of myopia in young children
The aim of the study was to investigate the relationship between serum 25(OH)D levels and axial length (AL) and myopia in 6-year-old children. A total of 2666 children aged 6 years participating in the birth-cohort study Generation R underwent a stepwise eye examination. First, presenting visual acuity (VA) and AL were performed. Second, automated cycloplegic refraction was measured if LogMAR VA > 0.1. Serum 25-hydroxyvitamin D [25(OH)D] was determined from blood using liquid chromatography/tandem mass spectrometry. Vitamin D related SNPs were determined with a SNP array; outdoor exposure was assessed by questionnaire. The relationships between 25(OH)D and AL or myopia were investigated using linear and logistic regression analysis. Average 25(OH)D concentration was 68.8 nmol/L (SD ± 27.5; range 4–211); average AL 22.35 mm (SD ± 0.7; range 19.2–25.3); and prevalence of myopia 2.3 % (n = 62). After adjustment for covariates, 25(OH)D concentration (per 25 nmol/L) was inversely associated with AL (β −0.043; P < 0.01), and after additional adjusting for time spent outdoors (β −0.038; P < 0.01). Associations were not different between European and non-European children (β −0.037 and β −0.039 respectively). Risk of myopia (per 25 nmol/L) was OR 0.65 (95 % CI 0.46–0.92). None of the 25(OH)D related SNPs showed an association with AL or myopia. Lower 25(OH)D concentration in serum was associated with longer AL and a higher risk of myopia in these young children. This effect appeared independent of outdoor exposure and may suggest a more direct role for 25(OH)D in myopia pathogenesis
Proteome biology of stem cells
AbstractThe notion that integration of cutting-edge technologies in stem cell research would be enhanced by proteomic analyses has emanated from rapid advances in proteome technology. These advances have increased the probability that basic properties of stem cells will be elucidated more effectively, leading to acceleration toward novel stem cell therapies. We have therefore sought to establish a world-wide alliance of proteomics and stem cell researchers, which has resulted in the foundation of an initiative supported by the Human Proteome Organisation (HUPO) and the International Society for Stem Cell Research (ISSCR) called the Proteome Biology of Stem Cells Initiative. Here we report on the rationale and goals of this initiative
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