3,051 research outputs found

    Low delta-V near-Earth asteroids: A survey of suitable targets for space missions

    Full text link
    In the last decades Near-Earth Objects (NEOs) have become very important targets to study, since they can give us clues to the formation, evolution and composition of the Solar System. In addition, they may represent either a threat to humankind, or a repository of extraterrestrial resources for suitable space-borne missions. Within this framework, the choice of next-generation mission targets and the characterisation of a potential threat to our planet deserve special attention. To date, only a small part of the 11,000 discovered NEOs have been physically characterised. From ground and space-based observations one can determine some basic physical properties of these objects using visible and infrared spectroscopy. We present data for 13 objects observed with different telescopes around the world (NASA-IRTF, ESO-NTT, TNG) in the 0.4 - 2.5 um spectral range, within the NEOSURFACE survey (http://www.oa-roma.inaf.it/planet/NEOSurface.html). Objects are chosen from among the more accessible for a rendez-vous mission. All of them are characterised by a delta-V (the change in velocity needed for transferring a spacecraft from low-Earth orbit to rendez-vous with NEOs) lower than 10.5 km/s, well below the Solar System escape velocity (12.3 km/s). We taxonomically classify 9 of these objects for the first time. 11 objects belong to the S-complex taxonomy; the other 2 belong to the C-complex. We constrain the surface composition of these objects by comparing their spectra with meteorites from the RELAB database. We also compute olivine and pyroxene mineralogy for asteroids with a clear evidence of pyroxene bands. Mineralogy confirms the similarity with the already found H, L or LL ordinary chondrite analogues.Comment: 9 pages, 7 figures, to be published in A&A Minor changes by language edito

    Investigation of early supplementation of nucleotides on the intestinal maturation of weaned piglets

    Get PDF
    Nucleotides are essential for the development of the gastrointestinal tract and immune function, but their intake with milk by piglets could be insufficient. The effect of nucleotides on growth and health was tested on 98 piglets divided into two groups: NU, orally administrated with 4 mL of a nucleotide-based product (SwineMOD® ) at 10, 15, 18, 21, 27 days, or not (CO). Blood and feces were sampled at weaning (26 d, T1), and at 38 d (T2). Per each group and time-point, eight piglets were slaughtered and jejunal Peyer’s patches (JPPs) were collected. NU increased hemoglobin content and hematocrit, but not growth. At weaning, the NU fecal microbiota was characterized by the abundance of Campylobacteraceae, more typical of the growing phase, compared to CO, with a greater abundance of Streptococcaceae. For the blood transcriptome, an initial greater inflammatory activation was seen in CO, while at T2, NU enriched gene sets related to erythropoiesis. The activation of gene groups ranging from epigenetic response to transcriptional regulation evidenced an intense proliferative activity in NU JPPs. NU supplementation did not influence the growth performance of piglets but could have expressed a positive effect on pig microbiota anticipating its maturation at weaning. This immunostimulant activity in the JPPs could moderate the inflammation in the immediate pre-weaning

    A review of power electronics equipment for all-electric ship MVDC power systems

    Get PDF
    Medium Voltage DC (MVDC) distribution Power Systems for all-electric ships (AES) can be regarded as functionally composed of three subsystems, namely the power sources, the load centers and the distribution network. Extensive use of power electronics is required for connecting power sources and load centers to the MVDC bus and for protecting the MVDC power system through properly placed DC circuit breakers. In this paper, an overview is given of the power electronics equipment found in the literature and on the market that could be suitable for use in future AES MVDC power systems. Some industrial experiences regarding DC generator systems, energy storage apparatus and solid-state DC circuit breaker prototypes are reported in the paper as examples of state-of-the-art realizations. Different DC/DC converters, which can be employed as solid-state transformers, are also discussed and a structure obtained by combining them is proposed

    The effect of a single, early-life administration of a probiotic on piglet growth performance and faecal microbiota until weaning

    Get PDF
    The establishment and maintenance of a balanced gut microbiota in early life play a pivotal role in pigs. This study aims to evaluate the effect of the administration of a single early-life probiotic on piglet faecal microbiota and growth performance until weaning. Forty-eight hours after birth (d0), 820 piglets were allocated into 4 groups (205 piglets/16 litters/group) and orally inoculated as follows: 1) Control (CO: 4 mL of pure water); 2) Saccharomyces (SA: 4 mL containing a total of 1 Ă— 1010 CFU of Saccharomyces cerevisiae var. boulardii CNCM-1079; 3) Enterococcus (EF: 4 mL containing a total of 1 Ă— 1010 CFU of Enterococcus faecium lactiferm WS200); 4) a mix of the two probiotics at the same doses (SAEF). At d7 and d18, the piglets were weighed, and faeces from the piglets (18 piglets/group from 6 sows/group) and their mothers were analysed for a microbial profile by sequencing the v3-v4 regions of the 16S rRNA gene. Data were arranged in a 2x2 factorial design. The probiotic supplement improved piglet ADG in the periods d7-d18 (p <.0001) and d0-d18 (p <.05). From d7 to d18, the SA group tended to have lower mortality than the CO group (p =.08). The probiotic supplement significantly affected the microbial beta diversity at d7 (p <.05). The SA probiotic favoured the colonisation of Erysipelatoclostridium and Christensenella, and the EF probiotic the colonisation of Lachnospiraceae. These results highlighted that the administration of a single early-life probiotic supplement could improve piglet performance and shape the faecal microbial profile.Highlights A single dose of E. faecium or S. cerevisiae improved piglet performance in the pre-weaning period. The early administration of probiotics shaped the faecal microbial profile of the piglets and contributed to improved growth performance

    Study of MDT calibration constants using H8 testbeam data of year 2004

    Get PDF
    In year 2004 Atlas performed a long campaign of test beam data taking at the H8 Cern beam. Two sectors of the barrel and endcap regions of the Muon Spectrometer were exposed to the beam and large amount of data were collected in well defined and controlled operating conditions. This allowed a careful study on MDT drift properties. A better understanding of the calibration constants, of their definition and determination and of the criteria for their acceptance has been obtained. Systematic effects and time stability of the constants have also been studied

    Ultrasonographic appearance of early embryonic mortality in buffalo (Bubalus bubalis)

    Get PDF
    Embryonic mortality is one of the main causes responsible of the decline in fertility that occurs in buffaloes during periods of increasing daylight length (out sexual breeding season). Transrectal ultrasonography for pregnancy diagnosis offers some advantages over palpation per rectum: earlier diagnosis of pregnancy/non-pregnancy, determination of embryo/fetus viability, reduction of misdiagnosis, and reduction of .potential. iatrogenic embryo/fetal attrition. Non pregnant buffaloes on Day 25 after AI showed higher Resistive Index (RI) (P<0.05) and Pulsatility Index (P=0.07) values, registered on CL on Days 10 after AI, compared to pregnant buffaloes. RI values were significantly higher (P=0.02) in non pregnant buffaloes also on Day 45 after AI. Colour Doppler sonography could be used to gain specific information relating to the ovarian blood flow in predicting early embryonic loss and to describe the ultrasonographic features of early embryonic death in buffaloes

    False versus True Statin Intolerance in Patients with Peripheral Artery Disease.

    Get PDF
    BACKGROUND Statin intolerance (SI) is often documented in patients' charts but rarely confirmed by objective methods. OBJECTIVE We aimed to identify the rate of true SI in a large population with peripheral artery disease (PAD) as well as the subsequent use of such drugs and the impact on cardiovascular outcomes. METHODS Patients with PAD and reported SI were retrospectively classified in those with "probable/possible" (pp) and "unlikely" (u) SI, after the application of the "Statin Myalgia Clinical Index Score" (SAMS-CI). Both groups were compared after 62 months (date of observation period?). RESULTS Among the 4,505 included patients, 139 (3%) had been reported as having SI. Of those, 33 (24%) had ppSI, and 106 (76%) had uSI. During the observation period, statin use decreased in patients with both ppSI (from 97% to 21%; p &lt; 0.0001) and uSI (from 87% to 53%; p &lt; 0.0001). At the end of the observation period, patients with ppSI more often received PCSK9 inhibitors (55% vs. 7%; p &lt; 0.0001), had a stronger decrease in LDL-C from baseline to follow-up (1.82 ± 1.69 mmol/L vs. 0.85 ± 1.41 mmol/L; p &lt; 0.01), and a lower rate of mortality (3% vs. 21%; p = 0.04) than those with uSI. CONCLUSIONS SI is low in PAD patients (3.1%), with only one quarter fulfilling the criteria of ppSI. The overdiagnosis of SI is related to an underuse of statins and an increased mortality in a short time period

    Exploring differential transcriptome between jejunal and cecal tissue of broiler chickens

    Get PDF
    Simple Summary: Intestinal main functions and different gut tract peculiarities in poultry are known. However, a wider view at the molecular level in terms of functional genes may contribute to deepening knowledge on less considered biological aspects, with possible differentiation in gene expression and functionality between gut tracts. This experiment aimed to extend the exploration of chicken gut functional aspects by scouting differential gene expression in the jejunum and cecum, which may help in the detection of new interesting functions from a biological point of view. The work identified key aspects linked to gut biological processes that may be worthy of further investigations in experimental studies considering factors which may specifically address peculiarities of the different chicken gut tracts at the molecular level. Abstract: The study proposed an exploratory functional analysis on differential gene expression of the jejunum and of cecum in chickens. For this study, 150 Ross 308 male chickens were randomly allotted in six pens (25 birds/pen) and fed the same commercial diet. From 19 birds of 42 days of age, jejunum and cecum mucosae were collected for RNA extraction for transcriptome microarray analysis. Differentially expressed genes (DEGs) submitted to DAVID (Database for Annotation, Visualization, and Integrated Discovery) and Gene Set Enrichment Analysis (GSEA) software evidenced enriched gene clusters for biological functions differentiated in the tissues. DAVID analysis in the jejunum showed enriched annotations for cell membrane integral components, PPAR (peroxisome proliferator-activated receptor) signaling pathway, and peroxisome and lipid metabolism, and showed DEGs for gluconeogenesis, not previously reported in chicken jejunum. The cecum showed enriched annotations for disulfide bond category, cysteine and methionine metabolism, glycoprotein category, cell cycle, and extracellular matrix (ECM). GSEA analysis in the jejunum showed peroxisome and PPAR signaling pathway-related gene sets, as found with DAVID, and gene sets for immune regulation, tryptophan and histidine metabolism, and renin\u2013angiotensin system, like in mammals. The cecum showed cell cycle and regulation processes, as well as ECM receptor interaction and focal adhesion-related gene sets. Typical intestinal functions specific for the gut site and interesting functional genes groups emerged, revealing tissue-related key aspects which future studies might take advantage of

    Data-driven Product-Process Optimization of N-isopropylacrylamide Microgel Flow-Synthesis

    Full text link
    Microgels are cross-linked, colloidal polymer networks with great potential for stimuli-response release in drug-delivery applications, as their size in the nanometer range allows them to pass human cell boundaries. For applications with specified requirements regarding size, producing tailored microgels in a continuous flow reactor is advantageous because the microgel properties can be controlled tightly. However, no fully-specified mechanistic models are available for continuous microgel synthesis, as the physical properties of the included components are only studied partly. To address this gap and accelerate tailor-made microgel development, we propose a data-driven optimization in a hardware-in-the-loop approach to efficiently synthesize microgels with defined sizes. We optimize the synthesis regarding conflicting objectives (maximum production efficiency, minimum energy consumption, and the desired microgel radius) by applying Bayesian optimization via the solver ``Thompson sampling efficient multi-objective optimization'' (TS-EMO). We validate the optimization using the deterministic global solver ``McCormick-based Algorithm for mixed-integer Nonlinear Global Optimization'' (MAiNGO) and verify three computed Pareto optimal solutions via experiments. The proposed framework can be applied to other desired microgel properties and reactor setups and has the potential of efficient development by minimizing number of experiments and modelling effort needed.Comment: Manuscript: 24 pages, 8 figures; SI: 9 pages, 3 figure
    • …
    corecore