Photometric variability in the old open cluster M 67. II. General Survey

We use differential CCD photometry to search for variability in BVI among 990 stars projected in and around the old open cluster M 67. In a previous paper we reported results for 22 cluster members that are optical counterparts to X-ray sources; this study focuses on the other stars in our observations. A variety of sampling rates were employed, allowing variability on time scales ranging from \sim 0.3 hours to \sim 20 days to be studied. Among the brightest sources studied, detection of variability as small as sigma approx 10 mmag is achieved (with > 3 sigma confidence); for the typical star observed, sensitivity to variability at levels sigma approx 20 mmag is achieved. The study is unbiased for stars with 12.5 < B < 18.5, 12.5 < V < 18.5, and 12 < I < 18 within a radius of about 10 arcmin from the cluster centre. In addition, stars with 10 < BVI < 12.5 were monitored in a few small regions in the cluster. We present photometry for all 990 sources studied, and report the variability characteristics of those stars found to be variable at a statistically significant level. Among the variables, we highlight several sources that merit future study, including stars located on the cluster binary sequence, stars on the giant branch, blue stragglers, and a newly discovered W UMa system.Comment: 12 pages, including 6 figures and 5 tables. Tables 1 and 3 only available in electronic version of paper. Accepted by A&

MicroRNA expression patterns of CD8+ T cells in acute and chronic brucellosis

Although our knowledge about Brucella virulence factors and the host response increase rapidly, the mechanisms of immune evasion by the pathogen and causes of chronic disease are still unknown. Here, we aimed to investigate the immunological factors which belong to CD8+ T cells and their roles in the transition of brucellosis from acute to chronic infection. Using miRNA microarray, more than 2000 miRNAs were screened in CD8+ T cells of patients with acute or chronic brucellosis and healthy controls that were sorted from peripheral blood with flow cytometry and validated through qRT-PCR. Findings were evaluated using GeneSpring GX (Agilent) 13.0 software and KEGG pathway analysis. Expression of two miRNAs were determined to display a significant fold change in chronic group when compared with acute or control groups. Both miRNAs (miR-126-5p and miR-47533p) were decreased (p 2). These miRNAs have the potential to be the regulators of CD8+ T cell-related marker genes for chronic brucellosis infections. The differentially expressed miRNAs and their predicted target genes are involved in MAPK signaling pathway, cytokine-cytokine receptor interactions, endocytosis, regulation of actin cytoskeleton, and focal adhesion indicating their potential roles in chronic brucellosis and its progression. It is the first study of miRNA expression analysis of human CD8+ T cells to clarify the mechanism of inveteracy in brucellosis

Near-threshold high spin amplification in a 1300 nm GaInNAs spin laser

Using continuous-wave optical pumping of a spin-VCSEL at room temperature, we find high spin amplification of the pump close to threshold within the communications wavelength window, here at 1300 nm. This facilitates a strong switch from left to right circularly polarised light emission, which has potential applications in polarisation encoding for data communications. We use a simple spin flip model to fit the experimental results and discuss the VCSEL parameters that affect this amplification

Meta-heurísticas para o problema do traveling purchaser

Tese de mestrado, Estatística e Investigação Operacional (Investigação Operacional), Universidade de Lisboa, Faculdade de Ciências, 2015Dados um conjunto de mercados potenciais, uma lista de itens e um depósito, o problema do traveling purchaser (PTP) consiste em determinar uma rota de custo mínimo começando e acabando no depósito e que contenha um subconjunto de mercados de forma a ser possível adquirir todos os itens da lista. Conhecem-se os itens disponíveis em cada mercado, bem como o respetivo custo de aquisição, e o custo de deslocação entre cada par de mercados e entre cada mercado e o depósito. Note-se que cada item é vendido em pelo menos um mercado, caso contrário o problema seria impossível. A cada rota está associado um custo que é a soma dos custos de deslocação e de aquisição. O PTP tem inúmeras variantes mas nesta dissertação apenas será estudada a variante do PTP sem capacidades. Pretende-se adquirir uma unidade de cada item e cada mercado tem disponível no máximo uma unidade. O PTP pertence à classe de problemas NP-difícil, sendo essa a principal razão pela qual se recorre a métodos heurísticos para o resolver. Nesta dissertação são apresentadas três meta-heurísticas, cada uma composta por um algoritmo genético seguido de um procedimento de pesquisa local. Os três algoritmos genéticos representam as diferentes hierarquias de decisão associadas a ambas as partes do problema: rota e aquisição. A pesquisa local é baseada em técnicas de add e drop. Para comparar os métodos propostos foram utilizadas instâncias de referência. Na generalidade dos casos o valor das soluções obtidas recorrendo às meta-heurísticas têm um desvio inferior a 1% relativamente ao valor da solução ótima tendo estas soluções sido obtidas num tempo computacional razoável. Comparativamente a métodos propostos por outros autores, as meta-heurísticas resolvem as instâncias de teste num tempo computacional inferior e oferecem soluções para casos de estudo que os outros métodos não conseguiam resolver.Given a set of markets, a list of items and a depot, the traveling purchaser problem (TPP) consists in determining one route with a minimal cost that satisfies the following conditions: it begins and ends in the depot and we need to be able to buy all the items in the list in the subset of markets that belong to the route. We know which items are sold in each market and their cost, and the cost of traveling between each pair of markets and between each market and the depot. Every item must be sold in at least one market or otherwise the problem would be impossible. Each route has a cost, which is the sum of the traveling cost with the purchase cost. There are several variants of the TPP but in this thesis we will study the uncapacited version. We only wish to buy a copy of each item which is the maximum quantity available in each market. The TPP belongs to the class of NP-hard problems and this is the main reason why heuristic methods are used to solve the problem under study. In this thesis we present three meta-heuristics, each one composed by a genetic algorithm and a local search procedure. The three genetic algorithms represent the several ways we can decide which part of the problem is more important: route, purchase or route and purchase. The local search procedure is based on add and drop techniques. To compare the meta-heuristics we used benchmark instances. In the majority of cases we obtained solutions with a gap lower than 1% regarding the optimal solution within a reasonable computational time. Comparing with methods proposed by other authors, ours are able to solve the benchmark instances in less time and can find solutions to instances that the other methods could not

Aeronautical engineering: A continuing bibliography with indexes (supplement 304)

This bibliography lists 453 reports, articles, and other documents introduced into the NASA scientific and technical information system in May 1994. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

A high-throughput screening identifies microRNA inhibitors that influence neuronal maintenance and/or response to oxidative stress

Oxidative stress; Small RNA sequencing; NeurodegenerationEstrés oxidativo; Secuenciación de ARN pequeño; NeurodegeneraciónEstrès oxidatiu; Seqüenciació d'ARN petit; NeurodegeneracióSmall non-coding RNAs (sncRNAs), including microRNAs (miRNAs) are important post-transcriptional gene expression regulators relevant in physiological and pathological processes. Here, we combined a high-throughput functional screening (HTFS) platform with a library of antisense oligonucleotides (ASOs) to systematically identify sncRNAs that affect neuronal cell survival in basal conditions and in response to oxidative stress (OS), a major hallmark in neurodegenerative diseases. We considered hits commonly detected by two statistical methods in three biological replicates. Forty-seven ASOs targeting miRNAs (miRNA-ASOs) consistently decreased cell viability under basal conditions. A total of 60 miRNA-ASOs worsened cell viability impairment mediated by OS, with 36.6% commonly affecting cell viability under basal conditions. In addition, 40 miRNA-ASOs significantly protected neuronal cells from OS. In agreement with cell viability impairment, damaging miRNA-ASOs specifically induced increased free radical biogenesis. miRNAs targeted by the detrimental ASOs are enriched in the fraction of miRNAs downregulated by OS, suggesting that the miRNA expression pattern after OS contributes to neuronal damage. The present HTFS highlighted potentially druggable sncRNAs. However, future studies are needed to define the pathways by which the identified ASOs regulate cell survival and OS response and to explore the potential of translating the current findings into clinical applications.This work was supported by the Spanish Ministry of Economy and Competitiveness and FEDER funds (SAF2014-60551-R and SAF2017-88452-R). We acknowledge the support of the Spanish Ministry of Economy, Industry and Competitiveness (MEIC) to the EMBL partnership and the Centro de Excelencia Severo Ochoa 2013-2017 (SEV-2012-0208). We acknowledge the support of the Spanish Ministry of Science Innovation and Universities, Maria Maeztu Unit of Excellence Programme. We thank the staff of the Genomics Unit for the preparation of sRNA libraries and sequencing and the staff of the Biomolecular Screening and Protein Technologies Unit for their help in the setting up the high-throughput screening

Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 4: Sections 15 through 21

The analyses performed to provide structural mass estimates for the arrow wing supersonic cruise aircraft are presented. To realize the full potential for structural mass reduction, a spectrum of approaches for the wing and fuselage primary structure design were investigated. The objective was: (1) to assess the relative merits of various structural arrangements, concepts, and materials; (2) to select the structural approach best suited for the Mach 2.7 environment; and (3) to provide construction details and structural mass estimates based on in-depth structural design studies. Production costs, propulsion-airframe integration, and advanced technology assessment are included

AgRISTARS: Foreign commodity production forecasting. Country summary report, Australia

Australia is one of the world's major growers and exporters of wheat and as such is one of the countries of interest in the AgRISTARS program which endeavors to develop technology to estimate crop production using aerospace remote sensing. A compilation of geographic, political, and agricultural information on Australia is presented. Also included is a summary of the aerospace remote sensing, meteorological, and ground-observed data which were collected with respect to Australia, as well as a summary of contacts between AgRISTARS and Australia personnel

Nearest neighbor - A new non-parametric test used for classifying spectral data

Nonparametric statistical interference program for spectral data classificatio

Extremophiles in an Antarctic Marine Ecosystem

Recent attempts to explore marine microbial diversity and the global marine microbiome have indicated a large proportion of previously unknown diversity. However, sequencing alone does not tell the whole story, as it relies heavily upon information that is already contained within sequence databases. In addition, microorganisms have been shown to present small-to-large scale biogeographical patterns worldwide, potentially making regional combinations of selection pressures unique. Here, we focus on the extremophile community in the boundary region located between the Polar Front and the Southern Antarctic Circumpolar Current in the Southern Ocean, to explore the potential of metagenomic approaches as a tool for bioprospecting in the search for novel functional activity based on targeted sampling efforts. We assessed the microbial composition and diversity from a region north of the current limit for winter sea ice, north of the Southern Antarctic Circumpolar Front (SACCF) but south of the Polar Front. Although, most of the more frequently encountered sequences were derived from common marine microorganisms, within these dominant groups, we found a proportion of genes related to secondary metabolism of potential interest in bioprospecting. Extremophiles were rare by comparison but belonged to a range of genera. Hence, they represented interesting targets from which to identify rare or novel functions. Ultimately, future shifts in environmental conditions favoring more cosmopolitan groups could have an unpredictable effect on microbial diversity and function in the Southern Ocean, perhaps excluding the rarer extremophiles