The first 8-13 micron spectra of globular cluster red giants: circumstellar silicate dust grains in 47 Tucanae (NGC 104)

We present 8-13 micron spectra of eight red giants in the globular cluster 47 Tucanae (NGC 104), obtained at the European Southern Observatory 3.6m telescope. These are the first mid-infrared spectra of metal-poor, low-mass stars. The spectrum of at least one of these, namely the extremely red, large-amplitude variable V1, shows direct evidence of circumstellar grains made of amorphous silicate.Comment: Accepted for publication in Astronomy and Astrophysics, 5 page

Building a collection of phage-derived capsular depolymerases to tackle relevant A. baumannii capsular types

A. baumannii is the major cause of nosocomial and drug-resistant infections, its capsule representing a major virulence factor. This pathogen evolved to display a high variety of capsular types for evading host defenses and protecting themselves from predators. Some bacteriophages also evolved to produce capsular depolymerases, enzymes that specifically bind and degrade the bacterial capsules, allowing these phages to overcome this barrier and proceed with the infection. In this study, 94 carbapenem-resistant A. baumannii clinical isolates (Northern region of Portugal, 2005-2012), were screened for their resistance genes by PCR. Genes Oxa-23, Imp-like and Oxa-24 were present in 76%, 20% and 16% of the isolates, respectively. Based on their resistance gene profile, the genomes of 23 strains were sequenced. Using in silico typing with Kaptive, we found 4 prevalent capsular types, namely, KL2 (39%), KL7 (30%), KL9 (4%) and KL120 (26%). Aiming at implementing an effective depolymerase-based anti-virulence strategy to control A. baumannii infections, we isolated novel capsular depolymerases from lytic and prophages, ending with an in-house collection of enzymes targeting 10 capsular types (KL1, KL2, KL9, KL19, KL30, KL32, KL38, KL44, KL45, KL67). Experiments using a human serum model proved that all capsular depolymerases can effectively sensitize A. baumannii to the host complement killing activity, that otherwise were resistant. Therefore, capsular depolymerases have demonstrated to be a very powerful anti-virulence weapon and an emerging solution to treat A.baumannii-related infections. As a result, the collection of capsular depolymerases available was expanded to 17 K-specific depolymerases, advancing the prospects of application of these enzymes to control A. baumannii infections.info:eu-repo/semantics/publishedVersio

A Spitzer c2d Legacy Survey to Identify and Characterize Disks with Inner Dust Holes

Understanding how disks dissipate is essential to studies of planet formation. However, identifying exactly how dust and gas dissipates is complicated due to difficulty in finding objects clearly in the transition of losing their surrounding material. We use Spitzer IRS spectra to examine 35 photometrically-selected candidate cold disks (disks with large inner dust holes). The infrared spectra are supplemented with optical spectra to determine stellar and accretion properties and 1.3mm photometry to measure disk masses. Based on detailed SED modeling, we identify 15 new cold disks. The remaining 20 objects have IRS spectra that are consistent with disks without holes, disks that are observed close to edge-on, or stars with background emission. Based on these results, we determine reliable criteria for identifying disks with inner holes from Spitzer photometry and examine criteria already in the literature. Applying these criteria to the c2d surveyed star-forming regions gives a frequency of such objects of at least 4% and most likely of order 12% of the YSO population identified by Spitzer. We also examine the properties of these new cold disks in combination with cold disks from the literature. Hole sizes in this sample are generally smaller than for previously discovered disks and reflect a distribution in better agreement with exoplanet orbit radii. We find correlations between hole size and both disk and stellar masses. Silicate features, including crystalline features, are present in the overwhelming majority of the sample although 10 micron feature strength above the continuum declines for holes with radii larger than ~7 AU. In contrast, PAHs are only detected in 2 out of 15 sources. Only a quarter of the cold disk sample shows no signs of accretion, making it unlikely that photoevaporation is the dominant hole forming process in most cases.Comment: 24 pages, 18 figures and 8 tables. Fixed a typo in Table

On the Evolution of Dust Mineralogy, From Protoplanetary Disks to Planetary Systems

Mineralogical studies of silicate features emitted by dust grains in protoplanetary disks and Solar System bodies can shed light on the progress of planet formation. The significant fraction of crystalline material in comets, chondritic meteorites and interplanetary dust particles indicates a modification of the almost completely amorphous ISM dust from which they formed. The production of crystalline silicates thus must happen in protoplanetary disks, where dust evolves to build planets and planetesimals. Different scenarios have been proposed, but it is still unclear how and when this happens. This paper presents dust grain mineralogy of a complete sample of protoplanetary disks in the young Serpens cluster. These results are compared to those in the young Taurus region and to sources that have retained their protoplanetary disks in the older Upper Scorpius and Eta Chamaeleontis stellar clusters, using the same analysis technique for all samples. This comparison allows an investigation of the grain mineralogy evolution with time for a total sample of 139 disks. The mean cluster age and disk fraction are used as indicators of the evolutionary stage of the different populations. Our results show that the disks in the different regions have similar distributions of mean grain sizes and crystallinity fractions (~10-20%) despite the spread in mean ages. Furthermore, there is no evidence of preferential grain sizes for any given disk geometry, nor for the mean cluster crystallinity fraction to increase with mean age in the 1-8 Myr range. The main implication is that a modest level of crystallinity is established in the disk surface early on (< 1 Myr), reaching a equilibrium that is independent of what may be happening in the disk midplane. These results are discussed in the context of planet formation, in comparison with mineralogical results from small bodies in our Solar System. [Abridged]Comment: Accepted for publication in the Astrophysical Journa

Optimizing the fast Rydberg quantum gate

The fast phase gate scheme, in which the qubits are atoms confined in sites of an optical lattice, and gate operations are mediated by excitation of Rydberg states, was proposed by Jaksch et al. Phys. Rev. Lett. 85, 2208 (2000). A potential source of decoherence in this system derives from motional heating, which occurs if the ground and Rydberg states of the atom move in different optical lattice potentials. We propose to minimize this effect by choosing the lattice photon frequency \omega so that the ground and Rydberg states have the same frequency-dependent polarizability \alpha(omega). The results are presented for the case of Rb.Comment: 5 pages, submitted to PR

Hábitos alimentares e risco de doenças cardiovasculares em universitários

Modelo de estudo: Pesquisa descritiva, observacional, transversal. Objetivo: Descrever qualitativamente a frequência de ingestão de determinados alimentos, considerados de risco e de proteção para doenças cardiovasculares (DCV), além de determinar o Escore de Risco de Framingham (ERF) em indivíduos supostamente saudáveis, estudantes de graduação de uma universidade pública brasileira. Metodologia: Participaram 97 estudantes, 45 homens e 52 mulheres, na faixa etária de 18 a 25 anos. Após assinatura do Termo de Consentimento Livre e Esclarecido (TCLE), aprovado pelo Comitê de Ética em Pesquisa, os estudantes preencheram um questionário com os dados da pesquisa. Foram estudados alimentos classificados como de risco e de proteção, conforme sua composição química avaliada por tabelas de alimentos. O teste Qui-quadrado fui utilizado quando as frequências esperadas foram iguais ou superiores a 5. Para os demais parâmetros foi utilizado o teste exato de Fischer. Resultados: Entre os alimentos protetores destacou-se a ingestão diária de legumes (33%), verduras (22%) e frutas (17%) e entre os de risco estão a ingestão diária de café/chás com açúcar (39%), maionese/ margarina/manteiga (34%) e doces (14%). Houve variação de consumo conforme o sexo, para as frequências de 0,1, 2 e 4 vezes por semana para os alimentos: farinha de milho/mandioca, biscoito maisena/caseiro/água e sal, aveia, frango com pele. Houve variação significativa de consumo diário entre os sexos para os alimentos: frutas, doces, maionese/margarina/manteiga, biscoito maisena/caseiro/ água e sal. Conclusões: Este estudo demonstrou que os estudantes universitários apresentaram uma maior frequência diária de ingestão de alimentos considerados de proteção para DCV do que alimentos de risco. Em adição, o ERF calculado demonstrou baixo risco de desenvolvimento de DCV nos indivíduos avaliados.Study Design: Descriptive, observational, cross-sectional. Aims: The aims of this study were to qualitatively describe the frequency of eating certain foods, as risk and protective for cardiovascular disease (CVD), and determine the Framingham Risk Score (FRS) in supposedly healthy individuals, graduate students from a Brazilian public university. Methodology: Participants were 97 students, 45 males and 52 females, 18-25 years. After signing the consent form, approved by the Ethics Committee on Research, students completed a questionnaire survey data. We studied food classified as risk and protection, as assessed by its chemical composition tables. The Chi-square test was used when the expected frequencies greater than or equal to 5. For other parameters we used the Fisher exact test. Results: Among the foods considered protective stood out the daily intake of vegetables (33%), greens (22%) and fruit (17%). Among the foods considered at risk are the daily intake of coffee / tea with sugar (39%), mayonnaise / margarine / butter (34%) and sweets (14%). There was variation in consumption according to sex, for the frequencies of 0, 1, 2 and 4 times a week for food: corn flour / cassava, cornstarch cookie /homemade cookie / water and salt cookie, oats, chicken with skin. There was significant variation in daily consumption between the sexes for food: fruit, sweets, mayonnaise / margarine / butter, cornstarch cookie / homemade cookie / water and salt cookie. Conclusion: This study showed that college students presented higher frequency of daily intake of foods considered protective for CVD than risk food. In addition, the calculated FRS demonstrated low risk of developing CVD in studied individuals

Identification of QTLs for grain yield and other traits in tropical maize under high and low soil-nitrogen environments.

Article purchased; Published online: 03 Nov 2017Low soil Nitrogen (low-N) is one of the most important abiotic stresses responsible for significant yield losses in maize (Zea mays. L.). The development and commercialization of low N tolerant genotypes can contribute to improved food security in developing countries. However, selection for low N tolerance is difficult because it is a complex trait with strong interaction between genotypes and environments. Marker assisted breeding holds great promise for improving such complex traits more efficiently in less time, but requires markers associated with the trait of interest. In this study, 150 BC2F1 families of CML 444 x CML 494 were evaluated at two location for two consecutive seasons to identify SNP markers associated with quantitative trait loci (QTLs) for yield and other agronomic traits under low- and high-N environments. A total of 13 QTLs were identified with 158 SNP markers, of which nine and four QTLs were detected under low- and high-N environments, respectively. Five QTLs one each for grain yield (qgy-1), days to silking (qdts-1) and anthesis- silking interval (qasi-6), and two for stay green characteristic (qsg-1 and qsg-4) were close to their adjacent markers, with an interval of 0.7 to 5.2 cM between them and explained phenotypic variance of 9 to 21%. These QTLs would be invaluable for rapid introgression of genomic regions into maize populations using marker assisted selection (MAS) approaches. However, further validation of these QTLs is needed before use in MAS

Comparison of two peptide radiotracers for prostate carcinoma targeting

OBJECTIVES: Scintigraphy is generally not the first choice treatment for prostate cancer, although successful studies using bombesin analog radiopeptides have been performed. Recently, a novel peptide obtained using a phage display library demonstrated an affinity for prostate tumor cells. The aim of this study was to compare the use of a bombesin analog to that of a phage display library peptide (DUP-1) radiolabeled with technetium-99m for the treatment of prostate carcinoma. The peptides were first conjugated to S-acetyl-MAG3 with a 6-carbon spacer, namely aminohexanoic acid. METHODS: The technetium-99m labeling required a sodium tartrate buffer. Radiochemical evaluation was performed using ITLC and was confirmed by high-performance liquid chromatography. The coefficient partition was determined, and in vitro studies were performed using human prostate tumor cells. Biodistribution was evaluated in healthy animals at various time points and also in mice bearing tumors. RESULTS: The radiochemical purity of both radiotracers was greater than 95%. The DUP-1 tracer was more hydrophilic (log P = -2.41) than the bombesin tracer (log P = -0.39). The biodistribution evaluation confirmed this hydrophilicity by revealing the greater kidney uptake of DUP-1. The bombesin concentration in the pancreas was greater than that of DUP-1 due to specific gastrin-releasing peptide receptors. Bombesin internalization occurred for 78.32% of the total binding in tumor cells. The DUP-1 tracer showed very low binding to tumor cells during the in vitro evaluation, although tumor uptake for both tracers was similar. The tumors were primarily blocked by DUP1 and the bombesin radiotracer primarily targeted the pancreas. CONCLUSION: Further studies with the radiolabeled DUP-1 peptide are recommended. With further structural changes, this molecule could become an efficient alternative tracer for prostate tumor diagnosis

Postingestive Modulation of Food Seeking Depends on Vagus-Mediated Dopamine Neuron Activity

Postingestive nutrient sensing can induce food preferences. However, much less is known about the ability of postingestive signals to modulate food-seeking behaviors. Here we report a causal connection between postingestive sucrose sensing and vagus-mediated dopamine neuron activity in the ventral tegmental area (VTA), supporting food seeking. The activity of VTA dopamine neurons increases significantly after administration of intragastric sucrose, and deletion of the NMDA receptor in these neurons, which affects bursting and plasticity, abolishes lever pressing for postingestive sucrose delivery. Furthermore, lesions of the hepatic branch of the vagus nerve significantly impair postingestive-dependent VTA dopamine neuron activity and food seeking, whereas optogenetic stimulation of left vagus nerve neurons significantly increases VTA dopamine neuron activity. These data establish a necessary role of vagus-mediated dopamine neuron activity in postingestive-dependent food seeking, which is independent of taste signaling.info:eu-repo/semantics/publishedVersio

Prime Focus Spectrograph - Subaru's future -

The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project has been endorsed by Japanese community as one of the main future instruments of the Subaru 8.2-meter telescope at Mauna Kea, Hawaii. This optical/near-infrared multi-fiber spectrograph targets cosmology with galaxy surveys, Galactic archaeology, and studies of galaxy/AGN evolution. Taking advantage of Subaru's wide field of view, which is further extended with the recently completed Wide Field Corrector, PFS will enable us to carry out multi-fiber spectroscopy of 2400 targets within 1.3 degree diameter. A microlens is attached at each fiber entrance for F-ratio transformation into a larger one so that difficulties of spectrograph design are eased. Fibers are accurately placed onto target positions by positioners, each of which consists of two stages of piezo-electric rotary motors, through iterations by using back-illuminated fiber position measurements with a wide-field metrology camera. Fibers then carry light to a set of four identical fast-Schmidt spectrographs with three color arms each: the wavelength ranges from 0.38 {\mu}m to 1.3 {\mu}m will be simultaneously observed with an average resolving power of 3000. Before and during the era of extremely large telescopes, PFS will provide the unique capability of obtaining spectra of 2400 cosmological/astrophysical targets simultaneously with an 8-10 meter class telescope. The PFS collaboration, led by IPMU, consists of USP/LNA in Brazil, Caltech/JPL, Princeton, & JHU in USA, LAM in France, ASIAA in Taiwan, and NAOJ/Subaru.Comment: 13 pages, 11 figures, submitted to "Ground-based and Airborne Instrumentation for Astronomy IV, Ian S. McLean, Suzanne K. Ramsay, Hideki Takami, Editors, Proc. SPIE 8446 (2012)