1,611 research outputs found
Exploring Replica-Exchange Wang-Landau sampling in higher-dimensional parameter space
We considered a higher-dimensional extension for the replica-exchange
Wang-Landau algorithm to perform a random walk in the energy and magnetization
space of the two-dimensional Ising model. This hybrid scheme combines the
advantages of Wang-Landau and Replica-Exchange algorithms, and the
one-dimensional version of this approach has been shown to be very efficient
and to scale well, up to several thousands of computing cores. This approach
allows us to split the parameter space of the system to be simulated into
several pieces and still perform a random walk over the entire parameter range,
ensuring the ergodicity of the simulation. Previous work, in which a similar
scheme of parallel simulation was implemented without using replica exchange
and with a different way to combine the result from the pieces, led to
discontinuities in the final density of states over the entire range of
parameters. From our simulations, it appears that the replica-exchange
Wang-Landau algorithm is able to overcome this difficulty, allowing exploration
of higher parameter phase space by keeping track of the joint density of
states.Comment: Proceedings of CCP2014 will appear in Journal of Physics: Conference
Series (JPCS), published by the IO
A Higher-Order Calculation of Scattering in Cut-Off Effective Field Theory
We report a next-to-leading-order (NLO) chiral perturbation theory
calculation of the neutron-proton scattering cross section in the
channel using a cut-off regularization. The inclusion of two-pion exchanges in
the irreducible diagrams -- or potential -- figuring at NLO is found to be
important in enlarging the domain of validity of the effective field theory. We
are able to reproduce the {\it empirical} scattering phase shift up to p=300
MeV -- which is comparable to the cutoff scale involved -- with an agreement
which is superior to results of other effective field theory approaches. We
also discuss the role of the cutoff as a renormalization prescription and the
importance of the explicit pion degree of freedom in scattering process.Comment: Substantial changes made in texts and Fig.2. To appear in Phys. Lett.
Weight-for-Height, Body Fat, and Development in Children in the East Asia and Pacific Region
Importance: Weight-for-height z score (WHZ) is a standard indicator of children’s nutritional status even though it does not fully reflect body fat.
Objective: To examine the combined association of WHZ and body fat with early development in the East Asia and Pacific region.
Design, Setting, and Participants: Children from the East Asia–Pacific Early Child Development Scales validation study, with full data available regarding their nutritional status and outcomes, were included in this cross-sectional analysis. In brief, a multilevel stratified random sampling was used to select representative samples from each participating country in the study. WHZ and body fat were independently trichotomized using established references and were combined to form a 9-category exposure variable. Data collection was performed between 2012 and 2014, and the analyses were conducted in June 2021.
Main Outcomes and Measures: The binary outcome variable of not being developmentally on track (hereafter referred to as poor development) was defined as a score less than the 25th percentile in the following domains: cognitive, language, socioemotional, motor development, and total development score. Poisson regression models were used to analyze the associations between the combined categories and poor development, adjusted for sociodemographic factors.
Results: A total of 6815 children (mean [SD] age, 4.02 [0.8] years; 3434 girls [50.4%]) had full data available and were included in this study. Compared with children with normal weight and normal fat, those with wasting and low body fat had the highest likelihood of total poor development (prevalence ratio, 1.47; 95% CI, 1.28-1.70), followed by those with normal weight but low fat (prevalence ratio, 1.23; 95% CI, 1.11-1.36). Similar associations were found in language, cognitive, and socioemotional development, but not in motor development.
Conclusions and Relevance: Poor development was more commonly found in children with low body fat independent of WHZ (wasted or normal weight). Early public health strategies may consider using a combination of WHZ and body fat as an indicator of poor development
Child maltreatment and cardiovascular disease: quantifying mediation pathways using UK Biobank
Background:
Child maltreatment is associated with cardiovascular disease (CVD), but mediation pathways have not been fully elucidated. The aim of the current study was to determine and quantify the underlying pathways linking child maltreatment and CVD.
Methods:
We conducted a retrospective cohort study using the UK Biobank. The number and types of child maltreatment, including abuse and neglect, were recalled by the participants. Lifestyle, biological, physical, and mental health factors measured at baseline were explored as potential mediators. Incident CVD was ascertained through record linkage after baseline measurement. Age, sex, ethnicity, area-based deprivation, and education level were adjusted for as confounders. Cox proportional hazard models were conducted to test for associations between child maltreatment and incident CVD.
Results:
A total of 152,040 participants who completed the child maltreatment assessment were included in the analyses, and one third reported at least one type of child maltreatment. There was a dose-response relationship between the number of maltreatment types and incident CVD. On average, each additional type of child maltreatment was associated with an 11% (95% CI 8–14%, P < 0.0001) increased risk of CVD. The majority (56.2%) of the association was mediated through depressive symptoms, followed by smoking (14.7%), high-density lipoprotein cholesterol (8.7%), and sleep duration (2.4%).
Conclusion:
Child maltreatment is associated with incident CVD through a combination of mental health, lifestyle, and biological pathways. Therefore, in addition to interventions to reduce the occurrence of child maltreatment, attention should be targeted at promoting healthy lifestyles and preventing, identifying, and treating depression among children and adults who have previously been maltreated
A Transcriptomic View of the Proteome Variability of Newborn and Adult Bothrops jararaca Snake Venoms
Bothrops jararaca is one of the most abundant venomous snake species in Brazil. It is primarily a nocturnal and generalist animal, however, it exhibits a notable ontogenetic shift in diet, feeding mainly on arthropods, lizards, and amphibians (ectothermic prey) through its juvenile phase and on small mammals (endothermic animals) during adult life. Due to its broad geographical distribution, this species is responsible for the majority of the accidents by Bothrops genus in Brazil. Studies on envenomation cases with newborn and adult B. jararaca snakes have shown distinct patterns, mainly related to blood coagulation disorders, which seems to be prominent in accidents with newborn specimens. Moreover, it has been demonstrated that the Brazilian commercial antibothropic antivenom, which is produced by immunization with adult venom, is less effective in neutralizing newborn venom effects. In this study we analyzed the venom gland transcriptome of newborn snake specimens and compared the content of toxin transcripts with that of adult specimens. We demonstrate that upon B. jararaca development, its repertoire of mRNAs encoding toxins changes both qualitatively and quantitatively and these alterations are associated with the venom proteome profiles and pharmacological activities displayed by newborn and adult specimens
Diet modifies the association between alcohol consumption and severe alcohol-related liver disease incidence
\ua9 The Author(s) 2024.It is elusive why some heavy drinkers progress to severe alcohol-related liver disease (ALD) while others do not. This study aimed to investigate if the association between alcohol consumption and severe ALD is modified by diet. This prospective study included 303,269 UK Biobank participants. Alcohol consumption and diet were self-reported. The diet score was created from 4 items selected using LASSO. Cox proportional hazard model showed that the diet score was monotonically associated with severe ALD risk, adjusted for sociodemographics, lifestyle factors, and alcohol consumption. Relative excess risk due to interaction analysis indicated that having a higher ALD diet score and a higher alcohol consumption simultaneously confers to 2.44 times (95% CI: 1.06-3.83) higher risk than the sum of excess risk of each factor. In this work, we show that people who have a poor diet might be more susceptible to severe ALD due to alcohol consumption
Some aspects of the venom proteome of the Colubridae snake Philodryas olfersii revealed from a Duvernoy’s (venom) gland transcriptome
AbstractWe investigated the putative toxins of Philodryas olfersii (Colubridae), a representative of a family of snakes neglected in venom studies despite their growing medical importance. Transcriptomic data of the venom gland complemented by proteomic analysis of the gland secretion revealed the presence of major toxin classes from the Viperidae family, including serine proteases, metalloproteases, C-type lectins, Crisps, and a C-type natriuretic peptide (CNP). Interestingly, the phylogenetic analysis of the CNP precursor showed it as a linker between two related precursors found in Viperidae and Elapidae snakes. We suggest that these precursors constitute a monophyletic group derived from the vertebrate CNPs
Thickening of galactic disks through clustered star formation
(Abridged) The building blocks of galaxies are star clusters. These form with
low-star formation efficiencies and, consequently, loose a large part of their
stars that expand outwards once the residual gas is expelled by the action of
the massive stars. Massive star clusters may thus add kinematically hot
components to galactic field populations. This kinematical imprint on the
stellar distribution function is estimated here by calculating the velocity
distribution function for ensembles of star-clusters distributed as power-law
or log-normal initial cluster mass functions (ICMFs). The resulting stellar
velocity distribution function is non-Gaussian and may be interpreted as being
composed of multiple kinematical sub-populations. The notion that the formation
of star-clusters may add hot kinematical components to a galaxy is applied to
the age--velocity-dispersion relation of the Milky Way disk to study the
implied history of clustered star formation, with an emphasis on the possible
origin of the thick disk.Comment: MNRAS, accepted, 27 pages, 9 figure
Optical vs. infrared studies of dusty galaxies and AGN: (I) Nebular emission lines
Optical nebular emission lines are commonly used to estimate the star
formation rate of galaxies and the black hole accretion rate of their central
active nucleus. The accuracy of the conversion from line strengths to physical
properties depends upon the accuracy to which the lines can be corrected for
dust attenuation. For studies of single galaxies with normal amounts of dust,
most dust corrections result in the same derived properties within the errors.
However, for statistical studies of populations of galaxies, or for studies of
galaxies with higher dust contents such as might be found in some classes of
"transition" galaxies, significant uncertainty arises from the dust attenuation
correction. We compare the strength of the predominantly unobscured mid-IR
[NeII]15.5um + [NeIII]12.8um emission lines to the optical H alpha emission
lines in four samples of galaxies: (i) ordinary star forming galaxies, (ii)
optically selected dusty galaxies, (iii) ULIRGs, (iv) Seyfert 2 galaxies. We
show that a single dust attenuation curve applied to all samples can correct H
alpha emission for dust attenuation to a factor better than 2. Similarly, we
compare mid-IR [OIV] and optical [OIII] luminosities to find that [OIII] can be
corrected to a factor better than 3. This shows that the total dust attenuation
suffered by the AGN narrow line region is not significantly different to that
suffered by the starforming HII regions in the galaxy. We provide explicit dust
attenuation corrections, together with errors, for [OII], [OIII] and H alpha.
The best-fit average attenuation curve is slightly greyer than the Milky-Way
extinction law, indicating either that external galaxies have slightly
different typical dust properties to the Milky Way, or that there is a
significant contribution from scattering. Finally, we uncover an intriguing
correlation between Silicate absorption and Balmer decrement.Comment: 19 pages, 9 figures, accepted for publication in MNRA
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