1,862 research outputs found
The track record of the Commission's forecasts - an update
This paper has updated the assessment of the Commission's forecasts' track record from 1999 by extending the observation period from 1969-1997 to also take into account the forecasts and outcome for the years 1998-2005. This update has also included some further tests on e.g. informational efficiency and undertaken a comparison with the forecasts of other international institutions and those of market participants. The tests were carried out on the forecasts for real GDP growth, total investment, inflation, the unemployment rate, the general government balance and the current account to GDP ratio. Data have been processed in a broadly similar manner compared to the study of 1999 to ensure comparability to the greatest degree possible. Overall, the Commission's forecasts continue to dispose a reasonable track record. For instance, the forecast error for the GDP forecast, as measured by the mean absolute error, has improved by 0.03 percentage point (pp.) to 0.5 pp. for the current-year outlook and by 0.08 pp. to 0.86 pp. for the year ahead. This implies that the Commission's forecasts for GDP growth has, on average, proven to be 0.5 pp. too high / low for the current year. Forecasts for the EU generally seem to be unbiased, efficient and display a high success rate for directional accuracy. The same holds true for the outlook for most Member States, although there are individual examples to the contrary. Moreover, in view of the importance of the international environment in explaining past forecast errors, it is reassuring to note that the forecasts for the largest non-EU countries generally seem to perform well. Finally, the Commission's forecasts' track record for GDP is broadly comparable with the ones of Consensus, the IMF and the OECD.forecasts, projections, economic outlook, GDP, growth, Melander, Sismanidis, Grenouilleau
Plasma levels of the proprotein convertase furin and incidence of diabetes and mortality
Background. Diabetes mellitus is linked to premature mortality of virtually all causes. Furin is a proprotein convertase broadly involved in the maintenance of cellular homeostasis; however, little is known about its role in the development of diabetes mellitus and risk of premature mortality. Objectives. To test if fasting plasma concentration of furin is associated with the development of diabetes mellitus and mortality. Methods. Overnight fasted plasma furin levels were measured at baseline examination in 4678 individuals from the population-based prospective Malmo Diet and Cancer Study. We studied the relation of plasma furin levels with metabolic and hemodynamic traits. We used multivariable Cox proportional hazards models to investigate the association between baseline plasma furin levels and incidence of diabetes mellitus and mortality during 21.3-21.7 years follow-up. Results. An association was observed between quartiles of furin concentration at baseline and body mass index, blood pressure and plasma concentration of glucose, insulin, LDL and HDL cholesterol (vertical bar 0.11 vertical bar Conclusion. Individuals with high plasma furin concentration have a pronounced dysmetabolic phenotype and elevated risk of diabetes mellitus and premature mortality.Peer reviewe
A Cross-Over in the Enstrophy Decay in Two-Dimensional Turbulence in a Finite Box
The numerical simulation of two-dimensional decaying turbulence in a large
but finite box presented in this paper uncovered two physically different
regimes of enstrophy decay. During the initial stage, the enstrophy, generated
by a random Gaussian initial condition, decays as t^{-gamma} with gamma
approximately 0.7-0.8. After that, the flow undergoes a transition to a gas or
fluid composed of distinct vortices. Simultaneously, the magnitude of the decay
exponent crosses over to gamma approximately 0.4. An exact relation for the
total number of vortices, N(t), in terms of the mean circulation of an
individual vortex is derived. A theory predicting that N(t) is proportional to
t^{-xi} and the magnitudes of exponents gamma=2/5 and xi=4/5 is presented and
the possibility of an additional very late-time cross-over to gamma=1/3 and
xi=2/3 is also discussed.Comment: 11 pages, 7 figure
Vortex line topology during vortex tube reconnection
This paper addresses reconnection of vortex tubes, with particular focus on
the topology of the vortex lines (field lines of the vorticity). This analysis
of vortex line topology reveals previously undiscovered features of the
reconnection process, such as the generation of many small flux rings, formed
when reconnection occurs in multiple locations in the vortex sheet between the
tubes. Consideration of three-dimensional reconnection principles leads to a
robust measurement of the reconnection rate, even once instabilities break the
symmetry. It also allows us to identify internal reconnection of vortex lines
within the individual vortex tubes. Finally, the introduction of a third vortex
tube is shown to render the vortex reconnection process fully
three-dimensional, leading to a fundamental change in the topological structure
of the process. An additional interesting feature is the generation of
vorticity null points.Comment: Accepted for publication in Physical Review Fluid
Numerical renormalization group of vortex aggregation in 2D decaying turbulence: the role of three-body interactions
In this paper, we introduce a numerical renormalization group procedure which
permits long-time simulations of vortex dynamics and coalescence in a 2D
turbulent decaying fluid. The number of vortices decreases as ,
with instead of the value predicted by a na\"{\i}ve
kinetic theory. For short time, we find an effective exponent
consistent with previous simulations and experiments. We show that the mean
square displacement of surviving vortices grows as .
Introducing effective dynamics for two-body and three-body collisions, we
justify that only the latter become relevant at small vortex area coverage. A
kinetic theory consistent with this mechanism leads to . We find that
the theoretical relations between kinetic parameters are all in good agreement
with experiments.Comment: 23 RevTex pages including 7 EPS figures. Submitted to Phys. Rev. E
(Some typos corrected; see also cond-mat/9911032
Quasi-stationary States of Two-Dimensional Electron Plasma Trapped in Magnetic Field
We have performed numerical simulations on a pure electron plasma system
under a strong magnetic field, in order to examine quasi-stationary states that
the system eventually evolves into. We use ring states as the initial states,
changing the width, and find that the system evolves into a vortex crystal
state from a thinner-ring state while a state with a single-peaked density
distribution is obtained from a thicker-ring initial state. For those
quasi-stationary states, density distribution and macroscopic observables are
defined on the basis of a coarse-grained density field. We compare our results
with experiments and some statistical theories, which include the
Gibbs-Boltzmann statistics, Tsallis statistics, the fluid entropy theory, and
the minimum enstrophy state. From some of those initial states, we obtain the
quasi-stationary states which are close to the minimum enstrophy state, but we
also find that the quasi-stationary states depend upon initial states, even if
the initial states have the same energy and angular momentum, which means the
ergodicity does not hold.Comment: 9 pages, 7 figure
FTO, Type 2 Diabetes, and Weight Gain Throughout Adult Life: A Meta-Analysis of 41,504 Subjects From the Scandinavian HUNT, MDC, and MPP Studies
OBJECTIVE—FTO is the most important polygene identified for obesity. We aimed to investigate whether a variant in FTO affects type 2 diabetes risk entirely through its effect on BMI and how FTO influences BMI across adult life span. RESEARCH DESIGN AND METHODS—Through regression models, we assessed the relationship between the FTO single nucleotide polymorphisms rs9939609, type 2 diabetes, and BMI across life span in subjects from the Norwegian population-based HUNT study using cross-sectional and longitudinal perspectives. For replication and meta-analysis, we used data from the Malmö Diet and Cancer (MDC) and Malmö Preventive Project (MPP) cohorts, comprising a total sample of 41,504 Scandinavians.RESULTS—The meta-analysis revealed a highly significant association for rs9939609 with both type 2 diabetes (OR 1.13; P = 4.5 3 1028) and the risk to develop incident type 2 diabetes (OR 1.16; P = 3.2 3 1028). The associations remained also after correction for BMI and other anthropometric measures. Furthermore, we confirmed the strong effect on BMI (0.28 kg/m2 per risk allele; P = 2.0 3 10226), with no heterogeneity between different age-groups. We found no differences in change of BMI over time according to rs9939609 risk alleles, neither overall (ΔBMI = 0.0[20.05, 0.05]) nor in any individual age stratum, indicating no further weight gain attributable to FTO genotype in adults. CONCLUSIONS—We have identified that a variant in FTO alters type 2 diabetes risk partly independent of its observed effect on BMI. The additional weight gain as a result of the FTO risk variant seems to occur before adulthood, and the BMI difference remains stable thereafter
Genetic risk prediction of atrial fibrillation
Background—Atrial fibrillation (AF) has a substantial genetic basis. Identification of individuals at greatest AF risk could minimize the incidence of cardioembolic stroke.
Methods—To determine whether genetic data can stratify risk for development of AF, we examined associations between AF genetic risk scores and incident AF in five prospective studies comprising 18,919 individuals of European ancestry. We examined associations between AF genetic risk scores and ischemic stroke in a separate study of 509 ischemic stroke cases (202 cardioembolic [40%]) and 3,028 referents. Scores were based on 11 to 719 common variants (≥5%) associated with AF at P-values ranging from <1x10-3 to <1x10-8 in a prior independent genetic association study.
Results—Incident AF occurred in 1,032 (5.5%) individuals. AF genetic risk scores were associated with new-onset AF after adjusting for clinical risk factors. The pooled hazard ratio for incident AF for the highest versus lowest quartile of genetic risk scores ranged from 1.28 (719 variants; 95%CI, 1.13-1.46; P=1.5x10-4) to 1.67 (25 variants; 95%CI, 1.47-1.90; P=9.3x10-15). Discrimination of combined clinical and genetic risk scores varied across studies and scores (maximum C statistic, 0.629-0.811; maximum ΔC statistic from clinical score alone, 0.009-0.017). AF genetic risk was associated with stroke in age- and sex-adjusted models. For example, individuals in the highest versus lowest quartile of a 127-variant score had a 2.49-fold increased odds of cardioembolic stroke (95%CI, 1.39-4.58; P=2.7x10-3). The effect persisted after excluding individuals (n=70) with known AF (odds ratio, 2.25; 95%CI, 1.20-4.40; P=0.01).
Conclusions—Comprehensive AF genetic risk scores were associated with incident AF beyond associations for clinical AF risk factors, though offered small improvements in discrimination. AF genetic risk was also associated with cardioembolic stroke in age- and sex-adjusted analyses. Efforts are warranted to determine whether AF genetic risk may improve identification of subclinical AF or help distinguish between stroke mechanisms
Role of Cross Helicity in Cascade Processes of MHD turbulence
The purpose of this work is to investigate the spectral properties of the
developed isotropic (non-Alfven) MHD turbulence stationary excited by an
external force, which injects the cross helicity into the flow simultaneously
with the energy. It is shown that the cross helicity blocks the spectral energy
transfer in MHD turbulence and results in energy accumulation in the system.
This accumulation proceeds until the vortex intensification compensates the
decreasing efficiency of nonlinear interactions. The formula for estimating the
average turbulence energy is obtained for the set ratio between the injected
helicity and energy. It is remarkable that the turbulence accumulates the
injected cross helicity at its low rate injection -- the integral correlation
coefficient significantly exceeds the ratio between the injected helicity and
the energy. It is shown that the spectrum slope gradually increases from "5/3"
to "2" with the cross helicity level.Comment: 4 page
Alterations in the neuropeptide galanin system in major depressive disorder involve levels of transcripts, methylation, and peptide
Major depressive disorder (MDD) is a substantial burden to
patients, families, and society, but many patients cannot be
treated adequately. Rodent experiments suggest that the
neuropeptide galanin (GAL) and its three G protein-coupled
receptors, GAL1–3, are involved in mood regulation. To explore
the translational potential of these results, we assessed the
transcript levels (by quantitative PCR), DNA methylation status
(by bisulfite pyrosequencing), and GAL peptide by RIA of the GAL
system in postmortem brains from depressed persons who had
committed suicide and controls. Transcripts for all four members
were detected and showed marked regional variations, GAL and
galanin receptor 1 (GALR1) being most abundant. Striking
increases in GAL and GALR3 mRNA levels, especially in the
noradrenergic locus coeruleus and the dorsal raphe nucleus, in
parallel with decreased DNA methylation, were found in both male
and female suicide subjects as compared with controls. In
contrast, GAL and GALR3 transcript levels were decreased, GALR1
was increased, and DNA methylation was increased in the
dorsolateral prefrontal cortex of male suicide subjects,
however, there were no changes in the anterior cingulate cortex.
Thus, GAL and its receptor GALR3 are differentially methylated
and expressed in brains of MDD subjects in a region- and sex-
specific manner. Such an epigenetic modification in GALR3, a
hyperpolarizing receptor, might contribute to the dysregulation
of noradrenergic and serotonergic neurons implicated in the
pathogenesis of MDD. Thus, one may speculate that a GAL3
antagonist could have antidepressant properties by disinhibiting
the firing of these neurons, resulting in increased release of
noradrenaline and serotonin in forebrain areas involved in mood
regulation
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