639 research outputs found

    The Bose–Hubbard model with squeezed dissipation

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    The stationary properties of the Bose–Hubbard model under squeezed dissipation are investigated. The dissipative model does not possess aU (1) symmetry but conserves parity. We find that 〈a j 〉 = 0 always holds, so no symmetry breaking occurs. Without the onsite repulsion, the linear case is known to be critical. At the critical point the system freezes to an EPR state with infinite two mode entanglement. We show here that the correlations are rapidly destroyed whenever the repulsion is switched on. As we increase the latter, the system approaches a thermal state with an effective temperature defined in terms of the squeezing parameter in the dissipators. We characterize this transition by means of a Gutzwiller ansatz and the Gaussian Hartree–Fock–Bogoliubov approximation

    Geographic distribution and habitat use of Lepidoblepharis miyatai (Squamata: Sphaerodactylidae), with comments on the taxonomic status of the genus in northern Colombia

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    Geographic distribution and habitat use of Lepidoblepharis miyatai (Squamata: Sphaerodactylidae), with comments on the taxonomic status of the genus in northern Colombia. We present some ecological and biogeographic data on Lepidoblepharis miyatai, a small and endangered gecko endemic to the northwestern foothills of the Sierra Nevada de Santa Marta (SNSM), 31 years after its description. Based on museum specimens and feld observations, we recorded four new localities with confrmed presence of L. miyatai. We calculated the extent of occurrence and altitudinal distribution of this species reaching 21.3 km2 and from sea level to 360 m respectively. Lepidoblepharis miyatai inhabits plant formations of scrub thorn and tropical deciduous forest. Based on microhabitat data obtained from 88 individuals observed in “Las Tinajas Village” we can state a differential use of three substrates with predominant use of leaf-litter. We consider L. miyatai an endemic species of the northwestern sector of the SNSM with a distribution range limited to the south-west by the occurrence of L. sanctaemartae, and towards the east by a thus far undetermined Lepidoblepharis species (here called Lepidoblepharis cf. sanctaemartae). We do not register sympatry of L. miyatai with any other congener. Accordingly, we consider that the recent records of this species in the southeast sector of SNSM are erroneous, given that the specimens cited as L. miyatai of this zone correspond to Lepidoblepharis cf. sanctaemartae. Finally, a reevaluation of the conservation status of L. miyatai is needed, including precise information of its distribution.Distribuição geográfca e uso de hábitat de Lepidoblepharis miyatai (Squamata: Sphaerodactylidae) com comentários sobre a taxonomia do gênero no norte da Colômbia. Apresentamos alguns dados ecológicos de Lepidoblepharis miyatai, um pequeno lagarto ameaçado endêmico das encostas norteocidentais da Sierra Nevada de Santa Marta (SNSM) 31 anos após sua descrição. Com base em exemplares depositados em coleções e observações de campo, registramos quatro novas localidades com presença confrmada de L. miyatai. Calculamos a extensão de ocorrência e a distribuição altitudinal dessa espécie com as localidades apresentadas, alcançando uma área de 21.3 km2 e uma variação altitudinal do nível do mar a 360 m. Essa espécie está presente em formações de bosque espinhoso e de foresta tropical decídua. Com informações sobre o uso de micro-hábitats obtidas de 88 indivíduos registrados em “Las Tinajas”, determinamos que essa espécie apresenta uso diferencial dos três tipos de substrato que ocupa, utilizando principalmente a serapilheira. Consideramos esse lagarto como endêmico do setor norte-ocidental de SNSM, com sua distribuição limitada a sudoeste pelo contato com Lepidoblepharis sanctaemartae e a leste com uma espécie indeterminada de Lepidoblepharis (aqui denominada Lepidoblepharis cf. sanctaemartae). Não registramos simpatria de L. miyatai com nenhuma dessas espécies congêneres. Do mesmo modo, consideramos errôneos os registros recentes dessa espécie no setor sul-oriental de SNSM, já que os exemplares citados previamente como L. miyatai nessa zona correspondem a Lepidoblepharis cf. sanctaemartae. Finalmente, se faz necessária uma reavaliação do estado de conservação de L. miyatai que incluam informações mais precisas sobre sua distribuição.Distribución geográfca y uso de hábitat de Lepidoblepharis miyatai (Squamata: Sphaerodactylidae) con comentarios sobre la taxonomía del género en el norte de Colombia. Presentamos algunos datos ecológicos de Lepidoblepharis miyatai, un pequeño y amenazado gecko endémico de las estribaciones noroccidentales de la Sierra Nevada de Santa Marta (SNSM) 31 años después de su descripción. Con base a ejemplares depositados en colecciones y observaciones en campo, registramos cuatro nuevas localidades con presencia confrmada de L. miyatai. Calculamos la extensión de ocurrencia y la distribución altitudinal de esta especie con las localidades presentadas, alcanzando un área de 21.3 km2 y un rango altitudinal entre el nivel del mar y los 360 m. Esta especie está presente en formaciones de matorral espinoso y bosque seco. Con la información de microhábitat obtenida de 88 individuos registrados en “Las Tinajas”, determinamos que esta especie presenta uso diferencial de los tres tipos de sustrato que ocupa, utilizando principalmente la hojarasca. Consideramos a este lagarto como endémico del sector noroccidental de la SNSM, limitando hacia occidente con el rango de distribución de Lepidoblepharis sanctaemartae y hacia oriente con una especie de Lepidoblepharis hasta ahora no determinada (denominada aquí como Lepidoblepharis cf. sanctaemartae). No registramos simpatría de L. miyatai con alguno de estos congéneres. De igual manera, consideramos que los registros recientes de esta especie en el sector suroriental de la SNSM son erróneos, dado a que los ejemplares citados previamente como L. miyatai en esta zona corresponden con Lepidoblepharis cf. sanctaemartae. Finalmente, se hace necesaria una reevaluación del estado de conservación de L. miyatai, donde se incluya la información más precisa de su distribución

    Plants Probiotics as a Tool to Produce Highly Functional Fruits: The Case of Phyllobacterium and Vitamin C in Strawberries

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    10 páginas, 1 tabla, 1 figuraThe increasing interest in the preservation of the environment and the health of consumers is changing production methods and food consumption habits. Functional foods are increasingly demanded by consumers because they contain bioactive compounds involved in health protection. In this sense biofertilization using plant probiotics is a reliable alternative to the use of chemical fertilizers, but there are few studies about the effects of plant probiotics on the yield of functional fruits and, especially, on the content of bioactive compounds. In the present work we reported that a strain of genus Phyllobacterium able to produce biofilms and to colonize strawberry roots is able to increase the yield and quality of strawberry plants. In addition, the fruits from plants inoculated with this strain have significantly higher content in vitamin C, one of the most interesting bioactive compounds in strawberries. Therefore the use of selected plant probiotics benefits the environment and human health without agronomical losses, allowing the production of highly functional foods.This work was granted by “Junta de Castilla y León” (Regional Government, Grant SA183A11-2) and MINECO (Central Government, Grant AGL2011-29227). Paula García-Fraile is recipient of a postdoctoral researcher contract from Academy of Sciences of the Czech Republic. José David Flores-Félix was supported by a fellowship of Salamanca University. Marta Marcos García was supported by a fellowship of Fundación Miguel Casado San José. Luís R. Silva is grateful to the financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through project Pest-C/EQB/LA0006/2013 and from the European Union (FEDER funds) under the framework of QREN through Project NORTE-07-0124-FEDER- 000069.Peer reviewe

    Power grid integration and use-case study of acid-base flow battery technology

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    There are many different types of energy storage systems (ESS) available and the functionality that they can provide is extensive. However, each of these solutions come with their own set of drawbacks. The acid-base flow battery (ABFB) technology aims to provide a route to a cheap, clean and safe ESS by means of providing a new kind of energy storage technology based on reversible dissociation of water via bipolar electrodialysis. First, the main characteristics of the ABFB technology are described briefly to highlight its main advantages and drawbacks and define the most-competitive use-case scenarios in which the technology could be applied, as well as analyze the particular characteristics which must be considered in the process of designing the power converter to be used for the interface with the electrical network. As a result, based on the use-cases defined, the ESS main specifications are going to be identified, pointing out the best power converter configuration alternatives. Finally, an application example is presented, showing an installation in the electrical network of Pantelleria (Italy) where a real pilot-scale prototype has been installed

    Whole-genome sequencing to understand the genetic architecture of common gene expression and biomarker phenotypes.

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    Initial results from sequencing studies suggest that there are relatively few low-frequency (<5%) variants associated with large effects on common phenotypes. We performed low-pass whole-genome sequencing in 680 individuals from the InCHIANTI study to test two primary hypotheses: (i) that sequencing would detect single low-frequency-large effect variants that explained similar amounts of phenotypic variance as single common variants, and (ii) that some common variant associations could be explained by low-frequency variants. We tested two sets of disease-related common phenotypes for which we had statistical power to detect large numbers of common variant-common phenotype associations-11 132 cis-gene expression traits in 450 individuals and 93 circulating biomarkers in all 680 individuals. From a total of 11 657 229 high-quality variants of which 6 129 221 and 5 528 008 were common and low frequency (<5%), respectively, low frequency-large effect associations comprised 7% of detectable cis-gene expression traits [89 of 1314 cis-eQTLs at P < 1 × 10(-06) (false discovery rate ∼5%)] and one of eight biomarker associations at P < 8 × 10(-10). Very few (30 of 1232; 2%) common variant associations were fully explained by low-frequency variants. Our data show that whole-genome sequencing can identify low-frequency variants undetected by genotyping based approaches when sample sizes are sufficiently large to detect substantial numbers of common variant associations, and that common variant associations are rarely explained by single low-frequency variants of large effect

    Tribological Behavior of Nanolubricants Based on Coated Magnetic Nanoparticles and Trimethylolpropane Trioleate Base Oil

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    The main task of this work is to study the tribological performance of nanolubricants formed by trimethylolpropane trioleate (TMPTO) base oil with magnetic nanoparticles coated with oleic acid: Fe3O4 of two sizes 6.3 nm and 10 nm, and Nd alloy compound of 19 nm. Coated nanoparticles (NPs) were synthesized via chemical co-precipitation or thermal decomposition by adsorption with oleic acid in the same step. Three nanodispersions of TMPTO of 0.015 wt% of each NP were prepared, which were stable for at least 11 months. Two different types of tribological tests were carried out: pure sliding conditions and rolling conditions (5% slide to roll ratio). With the aim of analyzing the wear by means of the wear scar diameter (WSD), the wear track depth and the volume of the wear track produced after the first type of the tribological tests, a 3D optical profiler was used. The best tribological performance was found for the Nd alloy compound nanodispersion, with reductions of 29% and 67% in friction and WSD, respectively, in comparison with TMPTO. On the other hand, rolling conditions tests were utilized to study friction and film thickness of nanolubricants, determining that Fe3O4 (6.3 nm) nanolubricant reduces friction in comparison to TMPTOThis research was supported by the Spanish Ministry of Economy and Competitiveness and the ERDF programme through the ENE2017-86425-C2-2-R project. Moreover, this work was funded by the Xunta de Galicia (ED431E 2018/08, GRC ED431C 2017/22 and GRC ED431C 2016/001). These three funders also financed the acquisition of the 3D Optical Profile Sensofar S Neox (UNST15-DE-3156)S

    Strong signature of natural selection within an FHIT intron implicated in prostate cancer risk

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    Previously, a candidate gene linkage approach on brother pairs affected with prostate cancer identified a locus of prostate cancer susceptibility at D3S1234 within the fragile histidine triad gene (FHIT), a tumor suppressor that induces apoptosis. Subsequent association tests on 16 SNPs spanning approximately 381 kb surrounding D3S1234 in Americans of European descent revealed significant evidence of association for a single SNP within intron 5 of FHIT. In the current study, resequencing and genotyping within a 28.5 kb region surrounding this SNP further delineated the association with prostate cancer risk to a 15 kb region. Multiple SNPs in sequences under evolutionary constraint within intron 5 of FHIT defined several related haplotypes with an increased risk of prostate cancer in European-Americans. Strong associations were detected for a risk haplotype defined by SNPs 138543, 142413, and 152494 in all cases (Pearson's χ2 = 12.34, df 1, P = 0.00045) and for the homozygous risk haplotype defined by SNPs 144716, 142413, and 148444 in cases that shared 2 alleles identical by descent with their affected brothers (Pearson's χ2 = 11.50, df 1, P = 0.00070). In addition to highly conserved sequences encompassing SNPs 148444 and 152413, population studies revealed strong signatures of natural selection for a 1 kb window covering the SNP 144716 in two human populations, the European American (π = 0.0072, Tajima's D= 3.31, 14 SNPs) and the Japanese (π = 0.0049, Fay & Wu's H = 8.05, 14 SNPs), as well as in chimpanzees (Fay & Wu's H = 8.62, 12 SNPs). These results strongly support the involvement of the FHIT intronic region in an increased risk of prostate cancer. © 2008 Ding et al
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