86 research outputs found
Thermoelectric Behaviour Near Magnetic Quantum Critical Point
We use the coupled 2d-spin-3d-fermion model proposed by Rosch {\sl et. al.}
(Phys. Rev. Lett. {\bf 79}, 159 (1997)) to study the thermoelectric behaviour
of a heavy fermion compound when it is close to an antiferromagnetic quantum
critical point. When the low energy spin fluctuations are quasi two
dimensional, as has been observed in and , with a typical 2d ordering wavevector and 3d Fermi
surface, the ``hot'' regions on the Fermi surface have a finite area. Due to
enhanced scattering with the nearly critical spin fluctuations, the electrons
in the hot region are strongly renormalized. We argue that there is an
intermediate energy scale where the qualitative aspects of the renormalized hot
electrons are captured by a weak-coupling perturbative calculation. Our
examination of the electron self energy shows that the entropy carried by the
hot electrons is larger than usual. This accounts for the anomalous logarithmic
temperature dependence of specific heat observed in these materials. We show
that the same mechanism produces logarithmic temperature dependence in
thermopower. This has been observed in . We
expect to see the same behaviour from future experiments on .Comment: RevTex, two-column, 7 pages, 2 figure
An efficient multi-objective evolutionary approach for solving the operation of multi-reservoir system scheduling in hydro-power plants
This paper tackles the short-term hydro-power unit commitment problem in a multi-reservoir system ? a cascade-based operation scenario. For this, we propose a new mathematical modeling in which the goal is to maximize the total energy production of the hydro-power plant in a sub-daily operation, and, simultaneously, to maximize the total water content (volume) of reservoirs. For solving the problem, we discuss the Multi-objective Evolutionary Swarm Hybridization (MESH) algorithm, a recently proposed multi-objective swarm intelligence-based optimization method which has obtained very competitive results when compared to existing evolutionary algorithms in specific applications. The MESH approach has been applied to find the optimal water discharge and the power produced at the maximum reservoir volume for all possible combinations of turbines in a hydro-power plant. The performance of MESH has been compared with that of well-known evolutionary approaches such as NSGA-II, NSGA-III, SPEA2, and MOEA/D in a realistic problem considering data from a hydro-power energy system with two cascaded hydro-power plants in Brazil. Results indicate that MESH showed a superior performance than alternative multi-objective approaches in terms of efficiency and accuracy, providing a profit of $412,500 per month in a projection analysis carried out.European CommissionAgencia Estatal de InvestigaciĂłnComunidad de Madri
Recommended from our members
Early phonological and sociocognitive skills as predictors of later language and social communication outcomes
Background:â Previous studies of outcome for children with early language delay have focused on measures of early language as predictors of language outcome. This study investigates whether very early processing skills (VEPS) known to underpin language development will be better predictors of specific language and social communication outcomes than measures of language itself.
Method:â Participants were 163 children referred to clinical services with concerns about language at 2;6â3;6 years and followed up at 4â5 years. Novel assessments of phonological and sociocognitive processing were administered at Time 1 (T1), together with a standardised test of receptive and expressive language, and parental report of expressive vocabulary. The language test was re-administered at Time 2 (T2), together with assessments of morphosyntax and parental reports of social communication.
Results:â Intercorrelations at and between T1 and T2 were high, and dissociations were rare. Ordinal regressions were run, entering predictors singly and simultaneously. With the exception of the phonological task, every early measure on its own was significantly predictive of most outcomes, and receptive language was the strongest all-round predictor. Results of simultaneous entry, controlling for the effect of other predictors, showed that early language was the strongest predictor of general language outcome, but early phonology was the strongest predictor of a measure of morphosyntax, and early sociocognition the strongest predictor of social communication.
Conclusions:â Language measures which draw on a wide range of skills were the strongest overall predictors of general language outcomes. However, our VEPS measures were stronger predictors of specific outcomes. The clinical and theoretical implications of these findings are discussed
Mapping and characterization of structural variation in 17,795 human genomes
A key goal of whole-genome sequencing for studies of human genetics is to interrogate all forms of variation, including single-nucleotide variants, small insertion or deletion (indel) variants and structural variants. However, tools and resources for the study of structural variants have lagged behind those for smaller variants. Here we used a scalable pipeline1 to map and characterize structural variants in 17,795 deeply sequenced human genomes. We publicly release site-frequency data to create the largest, to our knowledge, whole-genome-sequencing-based structural variant resource so far. On average, individuals carry 2.9 rare structural variants that alter coding regions; these variants affect the dosage or structure of 4.2 genes and account for 4.0â11.2% of rare high-impact coding alleles. Using a computational model, we estimate that structural variants account for 17.2% of rare alleles genome-wide, with predicted deleterious effects that are equivalent to loss-of-function coding alleles; approximately 90% of such structural variants are noncoding deletions (mean 19.1 per genome). We report 158,991 ultra-rare structural variants and show that 2% of individuals carry ultra-rare megabase-scale structural variants, nearly half of which are balanced or complex rearrangements. Finally, we infer the dosage sensitivity of genes and noncoding elements, and reveal trends that relate to element class and conservation. This work will help to guide the analysis and interpretation of structural variants in the era of whole-genome sequencing
Que signifie ĂȘtre parent dâun adolescent qui consomme des substances psychoactives ? Ătude phĂ©nomĂ©nologique interprĂ©tative transculturelle What does it mean being parent of a teenager who is using psychoactive substances? A transcultural phenomenological interpretative study
This study focuses on the theme of the influence of adolescents on parents, from a transcultural perspective considering the socio- cultural contexts of Belgium and Togo. The research question is: âHow do parents experience the influence of their teenagers who is using the psychoactive substances?â. Through an inductive qua- litative approach, the study highlighted, not the incidence of this phenomenon, but its existence and meaning, by the method of the interpretative phenomenological analysis. In order to reinforce the validity of the results, triangulations were made: triangulation of data sources (differences and diversity of participant characteris- tics), environmental triangulation (data collection from indigenous people in Belgium and Togo) and triangulation of investigators (involvement of co-authors at all stages: choice of methods, data collection and analysis). The analysis of the data collected from participants of Belgium brought out the following themes: (1) it is difficult for a parent to set limits on his child who is using the substances, (2) the substance use has benefits as well, (3) massive upset the parentsâ emotions, (4) the society doesnât offer enough protection against marginality, (5) it is necessary to protect oneself from societyâs accusing gaze. The themes that emerged from the analysis of data from participants of Togo are: (1) I cannot get res- pect in my own home, (2) exacerbation of parentsâ vulnerabilities, (3) beware that societyâs judgment is humiliating, (4) the chronic disorders have a religious explanation, (5) the relationship with the adolescent is complex and ambivalent. The results of this study thus show that where some participants refer to the difficult character of the adolescent to explain their educational failure, others may suspect, in addition, the intervention of mystical forces. They also suggest that the influence of substance-using teenager has essen- tially negative meanings and is a powerful factor of the parentsâ feelings and their educational practices that must be considered in psychotherapy
- âŠ