15,965 research outputs found
Clumping factors of HII, HeII and HeIII
Estimating the intergalactic medium ionization level of a region needs proper
treatment of the reionization process for a large representative volume of the
universe. The clumping factor, a parameter which accounts for the effect of
recombinations in unresolved, small-scale structures, aids in achieving the
required accuracy for the reionization history even in simulations with low
spatial resolution.
In this paper, we study for the first time the redshift evolution of clumping
factors of different ionized species of H and He in a small but very high
resolution simulation of the reionization process. We investigate the
dependence of the value and redshift evolution of clumping factors on their
definition, the ionization level of the gas, the grid resolution, box size and
mean dimensionless density of the simulations.Comment: 12 pages, 10 figures, 1 table. Accepted by MNRA
UHPLC-PDA-ESI-TOF/MS metabolic profiling and antioxidant capacity of arabica and robusta coffee silverskin: antioxidants vs phytotoxins
A deeper knowledge of the chemical composition of coffee silverskin (CS) is needed due to the growing interest in its use as a food additive or an ingredient of dietary supplements. Accordingly, the aim of this paper was to investigate the metabolic profile of aqueous extracts of two varieties of CS, Coffee arabica (CS-A), Coffee canephora var. robusta (CS-R) and of a blend of the two (CS-b) and to compare it to the profile of Coffee arabica green coffee (GC). Chlorogenic acids, caffeine, furokauranes, and atractyligenins, phytotoxins not previously detected in CS, were either identified or tentatively assigned. An unknown compound, presumably a carboxyatractyligenin glycoside was detected only in GC. Caffeine and chlorogenic acids were quantified while the content of furokauranes and atractyligens was estimated. GC and CS were also characterized in terms of total polyphenols and antioxidant capacity. Differences in the metabolites distribution, polyphenols and antioxidant capacity in CG and CS were detailed
Gender and Development: An Evaluation of World Bank Support, 2002-08
This evaluation reviews the World Bank's progress in gender integration from 2002 through 2008. Implementation of a 2001 gender strategy was initially strong, with integration into relevant projects peaking at 64% in 2003; but it declined between 2006 and 2008, due in part to the failure to implement an effective monitoring and evaluation system as outlined in the 2001 strategy
Cytoplasmic chromatin triggers inflammation in senescence and cancer
Chromatin is traditionally viewed as a nuclear entity that regulates gene expression and silencing. However, we recently discovered the presence of cytoplasmic chromatin fragments that pinch off from intact nuclei of primary cells during senescence, a form of terminal cell-cycle arrest associated with pro-inflammatory responses. The functional significance of chromatin in the cytoplasm is unclear. Here we show that cytoplasmic chromatin activates the innate immunity cytosolic DNA-sensing cGAS-STING (cyclic GMP-AMP synthase linked to stimulator of interferon genes) pathway, leading both to short-term inflammation to restrain activated oncogenes and to chronic inflammation that associates with tissue destruction and cancer. The cytoplasmic chromatin-cGAS-STING pathway promotes the senescence-associated secretory phenotype in primary human cells and in mice. Mice deficient in STING show impaired immuno-surveillance of oncogenic RAS and reduced tissue inflammation upon ionizing radiation. Furthermore, this pathway is activated in cancer cells, and correlates with pro-inflammatory gene expression in human cancers. Overall, our findings indicate that genomic DNA serves as a reservoir to initiate a pro-inflammatory pathway in the cytoplasm in senescence and cancer. Targeting the cytoplasmic chromatin-mediated pathway may hold promise in treating inflammation-related disorders
Autonomous virulence adaptation improves coevolutionary optimization
A novel approach for the autonomous virulence adaptation (AVA) of competing populations in a coevolutionary optimization framework is presented. Previous work has demonstrated that setting an appropriate virulence, v, of populations accelerates coevolutionary optimization by avoiding detrimental periods of disengagement. However, since the likelihood of disengagement varies both between systems and over time, choosing the ideal value of v is problematic. The AVA technique presented here uses a machine learning approach to continuously tune v as system engagement varies. In a simple, abstract domain, AVA is shown to successfully adapt to the most productive values of v. Further experiments, in more complex domains of sorting networks and maze navigation, demonstrate AVA's efficiency over reduced virulence and the layered Pareto coevolutionary archive.A novel approach for the autonomous virulence adaptation (AVA) of competing populations in a coevolutionary optimization framework is presented. Previous work has demonstrated that setting an appropriate virulence, v, of populations accelerates coevolutionary optimization by avoiding detrimental periods of disengagement. However, since the likelihood of disengagement varies both between systems and over time, choosing the ideal value of v is problematic. The AVA technique presented here uses a machine learning approach to continuously tune v as system engagement varies. In a simple, abstract domain, AVA is shown to successfully adapt to the most productive values of v. Further experiments, in more complex domains of sorting networks and maze navigation, demonstrate AVA's efficiency over reduced virulence and the layered Pareto coevolutionary archive
An API for IPv6 Multihoming based on HBA and CGA
EUNICE 2005. IFIP International Workshop on Networked Applications, Colmenarejo, Madrid/Spain, 6–8 July, 2005. (Proceedings of the 11th Open European Summer School EUNICE 2005: Networked Applications)This paper proposes an API for Multihoming in IPv6. This API is based on the Hash Based Addresses and Cryptographically Generated Addresses approaches, which are being developed by the IETF multi6 Working Group. The support of Multihoming implies several actions such as failure detection procedures, reachability tests, re-homing procedures and exchange of locators. Applications can benefit from transparent access to Multihoming services only if per host Multihoming parameters are defined. However, more benefits could be obtained by applications if they will be able to configure these parameters. The proposed Multihoming API provides different functions to applications which can modify some parameters and invoke some functions related with the Multihoming Layer.This work has been partly supported by the European Union under the E-Next Project FP6506869 and by OPTINET6 project TIC-2003-09042-C03-01
A Randomized Depression Prevention Trial Comparing Interpersonal Psychotherapy—Adolescent Skills Training To Group Counseling In Schools
Given the rise in depression disorders in adolescence, it is important to develop and study depression prevention programs for this age group. The current study examined the efficacy of Interpersonal Psychotherapy-Adolescent Skills Training (IPT-AST), a group prevention program for adolescent depression, in comparison to group programs that are typically delivered in school settings. In this indicated prevention trial, 186 adolescents with elevated depression symptoms were randomized to receive IPT-AST delivered by research staff or group counseling (GC) delivered by school counselors. Hierarchical linear modeling examined differences in rates of change in depressive symptoms and overall functioning from baseline to the 6-month follow-up assessment. Cox regression compared rates of depression diagnoses. Adolescents in IPT-AST showed significantly greater improvements in self-reported depressive symptoms and evaluator-rated overall functioning than GC adolescents from baseline to the 6-month follow-up. However, there were no significant differences between the two conditions in onset of depression diagnoses. Although both intervention conditions demonstrated significant improvements in depressive symptoms and overall functioning, results indicate that IPT-AST has modest benefits over groups run by school counselors which were matched on frequency and duration of sessions. In particular, IPT-AST outperformed GC in reduction of depressive symptoms and improvements in overall functioning. These findings point to the clinical utility of this depression prevention program, at least in the short-term. Additional follow-up is needed to determine the long-term effects of IPT-AST, relative to GC, particularly in preventing depression onset
On the Transferability of Knowledge among Vehicle Routing Problems by using Cellular Evolutionary Multitasking
Multitasking optimization is a recently introduced paradigm, focused on the
simultaneous solving of multiple optimization problem instances (tasks). The
goal of multitasking environments is to dynamically exploit existing
complementarities and synergies among tasks, helping each other through the
transfer of genetic material. More concretely, Evolutionary Multitasking (EM)
regards to the resolution of multitasking scenarios using concepts inherited
from Evolutionary Computation. EM approaches such as the well-known
Multifactorial Evolutionary Algorithm (MFEA) are lately gaining a notable
research momentum when facing with multiple optimization problems. This work is
focused on the application of the recently proposed Multifactorial Cellular
Genetic Algorithm (MFCGA) to the well-known Capacitated Vehicle Routing Problem
(CVRP). In overall, 11 different multitasking setups have been built using 12
datasets. The contribution of this research is twofold. On the one hand, it is
the first application of the MFCGA to the Vehicle Routing Problem family of
problems. On the other hand, equally interesting is the second contribution,
which is focused on the quantitative analysis of the positive genetic
transferability among the problem instances. To do that, we provide an
empirical demonstration of the synergies arisen between the different
optimization tasks.Comment: 8 pages, 1 figure, paper accepted for presentation in the 23rd IEEE
International Conference on Intelligent Transportation Systems 2020 (IEEE
ITSC 2020
Sea anemone model has a single Toll-like receptor that can function in pathogen detection, NF-κB signal transduction, and development
In organisms from insects to vertebrates, Toll-like receptors (TLRs) are primary pathogen detectors that activate downstream pathways, specifically those that direct expression of innate immune effector genes. TLRs also have roles in development in many species. The sea anemone Nematostella vectensis is a useful cnidarian model to study the origins of TLR signaling because its genome encodes a single TLR and homologs of many downstream signaling components, including the NF-κB pathway. We have characterized the single N. vectensis TLR (Nv-TLR) and demonstrated that it can activate canonical NF-κB signaling in human cells. Furthermore, we show that the intracellular Toll/IL-1 receptor (TIR) domain of Nv-TLR can interact with the human TLR adapter proteins MAL and MYD88. We demonstrate that the coral pathogen Vibrio coralliilyticus causes a rapidly lethal disease in N. vectensis and that heat-inactivated V. coralliilyticus and bacterial flagellin can activate a reconstituted Nv-TLR–to–NF-κB pathway in human cells. By immunostaining of anemones, we show that Nv-TLR is expressed in a subset of cnidocytes and that many of these Nv-TLR–expressing cells also express Nv-NF-κB. Additionally, the nematosome, which is a Nematostella-specific multicellular structure, expresses Nv-TLR and many innate immune pathway homologs and can engulf V. coralliilyticus. Morpholino knockdown indicates that Nv-TLR also has an essential role during early embryonic development. Our characterization of this primitive TLR and identification of a bacterial pathogen for N. vectensis reveal ancient TLR functions and provide a model for studying the molecular basis of cnidarian disease and immunity.IOS-1354935 - National Science Foundation (NSF); GRFP - National Science Foundation (NSF); GRFP - National Science Foundation (NSF); 1262934 - National Science Foundation (NSF); 2014-BSP - Arnold and Mabel Beckman Foundatio
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