Search for associations containing young stars (SACY). VII. New stellar and substellar candidate members in the young associations

Context. The young associations offer us one of the best opportunities to study the properties of young stellar and substellar objects and to directly image planets thanks to their proximity (<200 pc) and age (≈5−150 Myr). However, many previous works have been limited to identifying the brighter, more active members (≈1 M_⊙) owing to photometric survey sensitivities limiting the detections of lower mass objects. Aims. We search the field of view of 542 previously identified members of the young associations to identify wide or extremely wide (1000−100 000 au in physical separation) companions. Methods. We combined 2MASS near-infrared photometry (J, H, K) with proper motion values (from UCAC4, PPMXL, NOMAD) to identify companions in the field of view of known members. We collated further photometry and spectroscopy from the literature and conducted our own high-resolution spectroscopic observations for a subsample of candidate members. This complementary information allowed us to assess the efficiency of our method. Results. We identified 84 targets (45: 0.2−1.3 M_⊙, 17: 0.08−0.2 M_⊙, 22: <0.08 M_⊙) in our analysis, ten of which have been identified from spectroscopic analysis in previous young association works. For 33 of these 84, we were able to further assess their membership using a variety of properties (X-ray emission, UV excess, Hα, lithium and K I equivalent widths, radial velocities, and CaH indices). We derive a success rate of 76–88% for this technique based on the consistency of these properties. Conclusions. Once confirmed, the targets identified in this work would significantly improve our knowledge of the lower mass end of the young associations. Additionally, these targets would make an ideal new sample for the identification and study of planets around nearby young stars. Given the predicted substellar mass of the majority of these new candidate members and their proximity, high-contrast imaging techniques would facilitate the search for new low-mass planets.

A systematic review of economic evaluations of the use of robotic assisted laparoscopy in surgery compared with open or laparoscopic surgery

Peer reviewed

22 years of Predictive Testing for Huntington’s Disease : The Experience of the UK Huntington’s Prediction Consortium

Peer reviewed

Oligocene to early Miocene benthic foraminifera in the eastern Equatorial Pacific

We investigated Oligocene and early Miocene benthic foraminiferal faunas (> 105 µm in size) from Ocean Drilling Program (Leg 199) Site 1218 (4826 m water depth and ~3300 to ~4000 m paleo-water depth) and Site 1219 (5063 m water depth and ~4200 to ~4400 m paleo-water depth) to understand the response of abyssal benthic foraminifera to mid-Oligocene glacial events in the eastern Equatorial Pacific Ocean. Two principal factor assemblages were recognized. The Factor 1 assemblage (common Nuttallides umbonifer) is related to either an influx of the Southern Component Water (SCW), possibly carbonate undersaturated, or a decrease in seasonality of the food supply from the surface ocean. The Factor 2 assemblage is characterized by typical deep-sea taxa living under variable trophic conditions, possibly with a seasonal component in food supply. The occurrence of abyssal benthic foraminifera faunas during the mid-Oligocene depends on either the effect of SCW or the seasonality of food resources. The Factor 1 assemblage was most common near 76Ol-C11r, 73Ol-C10rn and 67Ol-C9n (ca. 30.2, 29.1 and 26.8 Ma respectively by Pälike et al. (2006, doi:10.1126/science.1133822)). This indicates that the effect of SCW increased or the seasonal input of food from the surface ocean to benthic environments was weakened close to these glacial events. In contrast, the huge export flux of small biogenic carbonate particles close to these glacial events might be responsible for carbonate-rich sediments buffering carbonate undersaturation. Changes in deep-water masses or the periodicity of food supply from the surface ocean and variation in surface carbonate production affected by orbital forcing had an impact on the mid-Oligocene faunas of abyssal benthic foraminifera around the intervals of glacial events in the eastern Equatorial Pacific Ocean. The Factor 1 assemblage decreased sharply at ? 30 Ma (29.8 Ma by Pälike et al. (2006), 30.0 Ma by CK95) and returned to dominance after ? 29 Ma (28.6 Ma by Pälike et al. (2006), 28.8 Ma by CK95). It is likely that the effect of SCW (possibly carbonate undersaturated) has intensified since the late Oligocene. The faunal transition of benthic foraminifera in the eastern Equatorial Pacific Ocean at ~29 Ma might be attributable to the influence of Northern Component Water (NCW) input to the Southern Ocean and the subsequent formation of SCW at about that time.

(Table S1) Stable isotope record and growth rates of cultured Mytilus edulis

To study the effects of temperature, salinity, and life processes (growth rates, size, metabolic effects, and physiological/genetic effects) on newly precipitated bivalve carbonate, we quantified shell isotopic chemistry of adult and juvenile animals of the intertidal bivalve Mytilus edulis (Blue mussel) collected alive from western Greenland and the central Gulf of Maine and cultured them under controlled conditions. Data for juvenile and adult M. edulis bivalves cultured in this study, and previously by Wanamaker et al. (2006, doi:10.1029/2005GC001189), yielded statistically identical paleotemperature relationships. On the basis of these experiments we have developed a species-specific paleotemperature equation for the bivalve M. edulis [T °C = 16.28 (±0.10) - 4.57 (±0.15) {d18Oc VPBD - d18Ow VSMOW} + 0.06 (±0.06) {d18Oc VPBD - d18Ow VSMOW}**2; r**2 = 0.99; N = 323; p < 0.0001]. Compared to the Kim and O'Neil (1997) inorganic calcite equation, M. edulis deposits its shell in isotope equilibrium (d18Ocalcite) with ambient water. Carbon isotopes (d13Ccalcite) from sampled shells were substantially more negative than predicted values, indicating an uptake of metabolic carbon into shell carbonate, and d13Ccalcite disequilibrium increased with increasing salinity. Sampled shells of M. edulis showed no significant trends in d18Ocalcite based on size, cultured growth rates, or geographic collection location, suggesting that vital effects do not affect d18Ocalcite in M. edulis. The broad modern and paleogeographic distribution of this bivalve, its abundance during the Holocene, and the lack of an intraspecies physiologic isotope effect demonstrated here make it an ideal nearshore paleoceanographic proxy throughout much of the North Atlantic Ocean.

A Group-Enhanced Sprint Interval Training Program for Amateur Athletes

Sprint interval training (SIT) can elicit improvements in aerobic and anaerobic capacity. While variations in SIT protocols have been investigated, the influence of social processes cannot be overlooked. As research supports the use of groups to influence individual cognitions and behaviours, the current project assessed the effectiveness of a group-based intervention with participants conducting SIT. Specifically, 53 amateur athletes (age, 21.9 ± 2.9 years; 53% females) took part in a 4-week training program (3 sessions per week, 30-s “all-out” efforts with 4 min active recovery, repeated 4–6 times per session), and were assigned to “true group”, aggregate, or individual conditions. Results indicated no significant differences between groups for the physiological measures. With regards to training improvements from baseline for all participants— regardless of condition — significant main effects for time were identified for maximal oxygen uptake (2.5–2.8 mL·kg−1·min−1, p < 0.001, η2 = 0.03), time-trial performance (14–32 s, p < 0.001, η2 = 0.37), and anaerobic power (1.1–1.7 k·h−1, p < 0.001, η2 = 0.66). With regards to the psychological measures, significant main effects between groups were found for motivation (p = 0.033, η2 = 0.13), task self-efficacy (p = 0.018, η2 = 0.15), and scheduling self-efficacy (p = 0.003, η2 = 0.22). The true group experienced greater improvements in motivation than the individual condition, but the aggregate and individual conditions demonstrated greater increases in task and scheduling self-efficacy. Though the SIT paradigm employed induced training improvements similar to previous work, the group intervention was not able to further these improvements

Concept maps as a tool to analyze the ideas of teacher training students regarding what to teach on human nutrition in Primary Education

Concept maps are a technique used to obtain a visual representation of a person's ideas about a concept or a set of related concepts. Specifically, in this paper, through a qualitative methodology, we analyze the concept maps proposed by 52 groups of teacher training students in order to find out the characteristics of the maps and the degree of adequacy of the contents with regard to the teaching of human nutrition in the 3rd cycle of primary education. The participants were enrolled in the Teacher Training Degree majoring in Primary Education, and the data collection was carried out through a training activity under the theme of what to teach about Science in Primary School? The results show that the maps are a useful tool for working in teacher education as they allow organizing, synthesizing, and communicating what students know. Moreover, through this work, it has been possible to see that future teachers have acceptable skills for representing the concepts/ideas in a concept map, although the level of adequacy of concepts/ideas about human nutrition and its relations is usually medium or low. These results are a wake-up call for teacher training, both initial and ongoing, because they shows the inability to change priorities as far as the selection of content is concerned.

Rate Maximization of Decode-and-Forward Relaying Systems with RF Energy Harvesting

We consider a three-node decode-and-forward (DF) half-duplex relaying system, where the source first harvests RF energy from the relay, and then uses this energy to transmit information to the destination via the relay. We assume that the information transfer and wireless power transfer phases alternate over time in the same frequency band, and their time fraction (TF) may change or be fixed from one transmission epoch (fading state) to the next. For this system, we maximize the achievable average data rate. Thereby, we propose two schemes: (1) jointly optimal power and TF allocation, and (2) optimal power allocation with fixed TF. Due to the small amounts of harvested power at the source, the two schemes achieve similar information rates, but yield significant performance gains compared to a benchmark system with fixed power and fixed TF allocation.

Role of substrate quality on the performance of semipolar (11 2 - 2) InGaN light-emitting diodes

We compare the optical properties and device performance of unpackaged InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) emitting at ∼430 nm grown simultaneously on a high-cost small-size bulk semipolar (11 2 - 2) GaN substrate (Bulk-GaN) and a low-cost large-size (11 2 - 2) GaN template created on patterned (10 1 - 2) r-plane sapphire substrate (PSS-GaN). The Bulk-GaN substrate has the threading dislocation density (TDD) of ∼ and basal-plane stacking fault (BSF) density of 0 cm-1, while the PSS-GaN substrate has the TDD of ∼2 × 108cm-2 and BSF density of ∼1 × 103cm-1. Despite an enhanced light extraction efficiency, the LED grown on PSS-GaN has two-times lower internal quantum efficiency than the LED grown on Bulk-GaN as determined by photoluminescence measurements. The LED grown on PSS-GaN substrate also has about two-times lower output power compared to the LED grown on Bulk-GaN substrate. This lower output power was attributed to the higher TDD and BSF density.

Interacção entre ácido valpróico e meropenem: um estudo retrospectivo

Introdução: existem múltiplos estudos acerca da interacção entre o ácido valpróico (AVP) e o meropenem, mas não estão bem definidas as recomendações para o seu uso concomitante, visto haver uns que indicam que os dois fármacos não devem ser administrados juntos e outros que apenas recomendam que os níveis de valproatémia sejam monitorizados. Também não existe informação consistente sobre possíveis repercussões clínicas desta interacção. O objectivo deste estudo foi analisar a interacção entre o AVP e o meropenem e as suas repercussões clínicas, em doentes hospitalizados e cronicamente medicados com o primeiro. Material e Métodos: trata-se de um estudo retrospectivo de uma amostra de doentes internados num hospital distrital no período de um ano. Os critérios de inclusão foram a existência de pelo menos uma determinação do nível sérico de AVP na semana anterior à prescrição de meropenem e outra durante o tratamento concomitante com os dois fármacos. Foi efectuada a análise estatística de 18 episódios. Resultados: Verificou-se um declínio médio estatisticamente significativo (p<0,001) de cerca de 83,4% dos níveis séricos de AVP após o início da terapêutica com meropenem e foram objectivadas crises convulsivas em 50% dos doentes. Discussão: a interacção entre os dois fármacos em questão é potencialmente grave, sendo que o número de doentes com manifestações clínicas desta interacção é maior que em estudos semelhantes. Conclusão: concluiu-se que a utilização concomitante dos dois fármacos deve ser evitada.

Dispersion and optimization of a calcium sulfoaluminate mortar prepared with superplasticizer

Calcium sulfoaluminate (CSA) cements/mortars are receiving increasing attention since their manufacture produces less CO2 than ordinary Portland cement (OPC) (up to 22% of decrease depending on its composition). These systems are complex and there are many parameters affecting their hydration mechanism, such as water-to-cement (w/c) ratio, type and amount of sulfate source, and so on. Low w/c ratios, within certain limits, may reduce the porosity and consequently, improve the mechanical strengths. However, it is accompanied by an increasing of viscosity and lack of both workability and homogeneity, with the consequent negative effect on the mechanical properties. The dispersion of the particles through the adsorption of the right amount and type of additives, such as superplasticizers, is a key point to improve the workability of mortars allowing both the preparation of homogeneous mixtures and the reduction of the amount of mixing water. This work deals with the preparation and optimization of homogeneous CSA-mortars with improved mechanical strengths. The optimum amount of superplasticizer was optimized through rheological measurements. The effect of different amounts of the superplasticizer on the viscosity of the mortars, its hydration mechanism and corresponding mechanical properties has been studied and will be discussed.

Synthesis and behavior of Belite-Alite-Ye’elimite (BAY) cement

Ye’elimite based cements have been studied since 70’s years in China, due to the irrelevant characteristics from a hydraulic and environmental point of view. One of them is the reduced fuel consumption, related to the lower temperature reaction required for this kind of cement production as compared to Ordinary Portland Cement (OPC), another characteristic is the reduced requirement of carbonates as a typical raw material, compared to OPC, with the consequent reduction in CO2 releases (~22%)from combustion. Thus, Belite-Ye’elimite-Ferrite (BYF) cements have been developed as potential OPC substitutes. BYF cements contain belite as main phase (>50 wt%) and ye´elimite as the second content phase (~30 wt%). However, an important technological problem is associated to them, related to the low mechanical strengths developed at intermediate hydration ages (3, 7 and 28 days). One of the proposed solutions to this problem is the activation of BYF clinkers by preparing clinkers with high percentage of coexisting alite and ye'elimite. These clinkers are known Belite-Alite-Ye’elimite (BAY) cements. Their manufacture would produce ~15% less CO2 than OPC. Alite is the main component of OPC and is responsible for early mechanical strengths. The reaction of alite and ye´elimite with water will develop cements with high mechanical strengths at early ages, while belite will contribute to later curing times. Moreover, the high alkalinity of BAY cement pastes/mortars/concretes may facilitate the use of supplementary cementitious materials with pozzolanic activity which also contributes to decrease the CO2 footprint of these ecocements. The main objective of this work was the design and optimization of all the parameters evolved in the preparation of a BAY eco-cement that develop higher mechanical strengths than BYF cements. These parameters include the selection of the raw materials (lime, gypsum, kaolin and sand), milling, clinkering conditions (temperature, and holding time), and clinker characterization The addition of fly ash has also been studied. All BAY clinker and pastes (at different hydration ages) were mineralogically characterized through laboratory X-ray powder diffraction (LXRPD) in combination with the Rietveld methodology to obtain the full phase assemblage including Amorphous and Crystalline non-quantified, ACn, contents. The pastes were also characterized through rheological measurements, thermal analyses (TA), scanning electronic microscopy (SEM) and nuclear magnetic resonance (NMR). The compressive strengths were also measured at different hydration times and compared to BYF.

Protozoan parasites of Xiphophorus spp. (Poeciliidae) and their relation with water characteristics

Investigou-se a relação entre as características da água e a infestação de protozoários parasitos, Icthyophthirius multifiliis e Trichodina sp., em peixe espada, Xiphophorus helleri e em plati, Xiphophorus maculatus, coletados em uma piscicultura de peixes ornamentais no Estado de São Paulo, Brasil. Os peixes foram coletados mensalmente, durante um ano, dos viveiros e das caixas de estocagem. A prevalência da infestação nos peixes das caixas e dos viveiros foram, respectivamente, 34,2% e 22,5% para I. multifiliis e 13% e 54% para Trichodina sp. A elevada condutividade elétrica e o pH da água reduziram a infestação por I. multifiliis. A baixa concentração de oxigênio resultou em aumento na infestação por Trichodina sp. O uso do sal, para aumentar a condutividade elétrica da água, consistiu em um método de controle de I. multifiliis. A redução do oxigênio dissolvido e a adição de fertilizante orgânico favoreceram a reprodução de Trichodina sp.

Proton Form Factor Puzzle and the CEBAF Large Acceptance Spectrometer(CLAS) Two-Photon Exchange Experiment

The electromagnetic form factors are the most fundamental observables that encode information about the internal structure of the nucleon. The electric ($G_{E}$) and the magnetic ($G_{M}$) form factors contain information about the spatial distribution of the charge and magnetization inside the nucleon. A significant discrepancy exists between the Rosenbluth and the polarization transfer measurements of the electromagnetic form factors of the proton. One possible explanation for the discrepancy is the contributions of two-photon exchange (TPE) effects. Theoretical calculations estimating the magnitude of the TPE effect are highly model dependent, and limited experimental evidence for such effects exists. Experimentally, the TPE effect can be measured by comparing the ratio of positron-proton elastic scattering cross section to that of the electron-proton $\large(R = \frac{\sigma (e^{+}p)}{\sigma (e^{-}p)}\large)$. The ratio $R$ was measured over a wide range of kinematics, utilizing a 5.6 GeV primary electron beam produced by the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. This dissertation explored dependence of $R$ on kinematic variables such as squared four-momentum transfer ($Q^{2}$) and the virtual photon polarization parameter ($\varepsilon$). A mixed electron-positron beam was produced from the primary electron beam in experimental Hall B. The mixed beam was scattered from a liquid hydrogen (LH$_{2}$) target. Both the scattered lepton and the recoil proton were detected by the CEBAF Large Acceptance Spectrometer (CLAS). The elastic events were then identified by using elastic scattering kinematics. This work extracted the $Q^{2}$ dependence of $R$ at high $\varepsilon$ ($\varepsilon > $ 0.8) and the $\varepsilon$ dependence of $R$ at $\langle Q^{2} \rangle \approx 0.85$ GeV$^{2}$. In these kinematics, our data confirm the validity of the hadronic calculations of the TPE effect by Blunden, Melnitchouk, and Tjon. This hadronic TPE effect, with additional corrections contributed by higher excitations of the intermediate state nucleon, largely reconciles the Rosenbluth and the polarization transfer measurements of the electromagnetic form factors.