A comparative assessment of different deviation strategies for dangerous NEO

In this paper a number of deviation strategies for dangerous Near Earth Objects (NEO) have been compared. For each strategy (i.e. Solar Collector, Nuclear Blast, Kinetic Impactor, Low-thrust Propulsion, Mass Driver) a multi criteria optimisation method has been used to reconstruct the set of Pareto optimal solutions minimising the mass of the spacecraft and the warning time, and maximising the deviation. Then, a dominance criterion has been defined and used to compare all the Pareto sets. The achievable deviation at the MOID, either for a low-thrust or for an impulsive variation of the orbit of the NEO, has been computed through a set of analytical formulas. The variation of the orbit of the NEO has been estimated through a deviation action model that takes into account the wet mass of the spacecraft at the Earth. Finally the technology readiness level of each strategy has been used to compute a more realistic value for the required warning time

Effects of short term fasting on mRNA expression of ghrelin and the peptide transporters PepT1 and 2 in Atlantic salmon (Salmo salar)

Food intake is a vital process that supplies necessary energy and essential nutrients to the body. Information regarding luminal composition in the gastrointestinal tract (GIT) collected through mechanical and nutrient sensing mechanisms are generally conveyed, in both mammals and fish, to the hypothalamic neurocircuits. In this context, ghrelin, the only known hormone with an orexigenic action, and the intestinal peptide transporters 1 and 2, involved in absorption of dietary di- and tripeptides, exert important and also integrated roles for the nutrient uptake. Together, both are potentially involved in signaling pathways that control food intake originating from different segments of the GIT. However, little is known about the role of different paralogs and their response to fasting. Therefore, after 3 weeks of acclimatization, 12 Atlantic salmon (Salmo salar) post-smolt were fasted for 4 days to explore the gastrointestinal response in comparison with fed control (n = 12). The analysis covered morphometric (weight, length, condition factor, and wet content/weight fish %), molecular (gene expression variations), and correlation analyses. Such short-term fasting is a common and recommended practice used prior to any handling in commercial culture of the species. There were no statistical differences in length and weight but a significant lower condition factor in the fasted group. Transcriptional analysis along the gastrointestinal segments revealed a tendency of downregulation for both paralogous genes slc15a1a and slc15a1b and with significant lowered levels in the pyloric ceca for slc15a1a and in the pyloric ceca and midgut for slc15a1b. No differences were found for slc15a2a and slc15a2b (except a higher expression of the fasted group in the anterior midgut), supporting different roles for slc15 paralogs. This represents the first report on the effects of fasting on slc15a2 expressed in GIT in teleosts. Transcriptional analysis of ghrelin splicing variants (ghrl-1 and ghrl-2) showed no difference between treatments. However, correlation analysis showed that the mRNA expression for all genes (restricted to segment with the highest levels) were affected by the residual luminal content. Overall, the results show minimal effects of 4 days of induced fasting in Atlantic salmon, suggesting that more time is needed to initiate a large GIT response.publishedVersio

Characterization of phytoplankton by pigment analysis and the detection of toxic cyanobacteria in reservoirs with aquaculture production

Made available in DSpace on 2018-12-11T17:19:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01The intensified use of water bodies and reservoirs for aquaculture production has increased the need for monitoring and early warning of toxins from cyanobacteria. To minimize effects from toxins, simple and fast analytical monitoring methods are crucial. Here, the content of pigments and microcystins in 14 different strains of cyanobacteria cultured under different growth conditions was investigated to determine the influence of light and nutrient starvation on pigment/ chlorophyll a (chl a) ratios. The obtained pigment/chl a ratios were applied in the software CHEMTAX to calculate the biomass of toxic cyanobacteria, as well as other phytoplankton groups. CHEMTAX ratios from the laboratory cultures were applied to water samples collected during 4 sampling periods at 6 fish farms in different reservoirs in São Paulo State, Brazil. Cyanobacteria generally dominated in all reservoirs in all sampling periods and constituted on average 44 to 66% of the average phytoplankton biomass. The concentrations of microcystins were significantly correlated with the chl a concentrations of cyanobacteria and showed that the pigment method can be used to detect microcystin-producing cyanobacteria in these Brazilian reservoirs. When the concentration of cyanobacteria in the reservoirs was above 4 μg chl a l-1, microcystins were always detected. Our results show that pigment analysis can be used to provide fast and reliable results for the early warning, the presence and potential risk of toxic cyanobacteria in freshwater reservoirs used for aqua culture.Environment and Toxicology DHISão Paulo State Agribusiness Agency TechnologySection of Microbial Ecology and Biotechnology Department of Plant and Environmental Sciences University of CopenhagenFicology Department Botanical InstituteUNESP Campus Botucatu Institute of Biosciences Parasitology DepartmentUNESP Campus Botucatu Institute of Biosciences Parasitology Departmen

Real-time monitoring of Pseudomonas aeruginosa biofilm formation on endotracheal tubes in vitro

BACKGROUND: Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for both acute and chronic infections in humans. In particular, its ability to form biofilm, on biotic and abiotic surfaces, makes it particularly resistant to host's immune defenses and current antibiotic therapies as well. Innovative antimicrobial materials, like hydrogel, silver salts or nanoparticles have been used to cover new generation catheters with promising results. Nevertheless, biofilm remains a major health problem. For instance, biofilm produced onto endotracheal tubes (ETT) of ventilated patients plays a relevant role in the onset of ventilation-associated pneumonia. Most of our knowledge on Pseudomonas aeruginosa biofilm derives from in vitro studies carried out on abiotic surfaces, such as polystyrene microplates or plastic materials used for ETT manufacturing. However, these approaches often provide underestimated results since other parameters, in addition to bacterial features (i.e. shape and material composition of ETT) might strongly influence biofilm formation. RESULTS: We used an already established biofilm development assay on medically-relevant foreign devices (CVC catheters) by a stably transformed bioluminescent (BLI)-Pseudomonas aeruginosa strain, in order to follow up biofilm formation on ETT by bioluminescence detection. Our results demonstrated that it is possible: i) to monitor BLI-Pseudomonas aeruginosa biofilm development on ETT pieces in real-time, ii) to evaluate the three-dimensional structure of biofilm directly on ETT, iii) to assess metabolic behavior and the production of microbial virulence traits of bacteria embedded on ETT-biofilm. CONCLUSIONS: Overall, we were able to standardize a rapid and easy-to-perform in vitro model for real-time monitoring Pseudomonas aeruginosa biofilm formation directly onto ETT pieces, taking into account not only microbial factors, but also ETT shape and material. Our study provides a rapid method for future screening and validation of novel antimicrobial drugs as well as for the evaluation of novel biomaterials employed in the production of new classes of ETT

A Medium Survey of the Hard X-Ray Sky with ASCA. II.: The Source's Broad Band X-Ray Spectral Properties

A complete sample of 60 serendipitous hard X-ray sources with flux in the range $\sim 1 \times 10^{-13}$ \ecs to $\sim 4 \times 10^{-12}$ \ecs (2 - 10 keV), detected in 87 ASCA GIS2 images, was recently presented in literature. Using this sample it was possible to extend the description of the 2-10 keV LogN(>S)-LogS down to a flux limit of $\sim 6\times 10^{-14}$ \ecs (the faintest detectable flux), resolving about a quarter of the Cosmic X-ray Background. In this paper we have combined the ASCA GIS2 and GIS3 data of these sources to investigate their X-ray spectral properties using the "hardness" ratios and the "stacked" spectra method. Because of the sample statistical representativeness, the results presented here, that refer to the faintest hard X-ray sources that can be studied with the current instrumentation, are relevant to the understanding of the CXB and of the AGN unification scheme.Comment: 28 pages plus 6 figures, LaTex manuscript, Accepted for publication in the Astrophysical Journal, Figure 5 can retrieved via anonymous ftp at ftp://ftp.brera.mi.astro.it/pub/ASCA/paper2/fig5.ps.g

The peptide transporter 1a of the zebrafish Danio rerio, an emerging model in nutrigenomics and nutrition research: Molecular characterization, functional properties, and expression analysis

Background: Peptide transporter 1 (PepT1, alias Slc15a1) mediates the uptake of dietary di/tripeptides in all vertebrates. However, in teleost fish, more than one PepT1-type transporter might function, due to specific whole genome duplication event(s) that occurred during their evolution leading to a more complex paralogue gene repertoire than in higher vertebrates (tetrapods). Results: Here, we describe a novel di/tripeptide transporter in the zebrafish (Danio rerio), i.e., the zebrafish peptide transporter 1a (PepT1a; also known as Solute carrier family 15 member a1, Slc15a1a), which is a paralogue (78% similarity, 62% identity at the amino acid level) of the previously described zebrafish peptide transporter 1b (PepT1b, alias PepT1; also known as Solute carrier family 15 member 1b, Slc15a1b). Also, we report a basic analysis of the pept1a (slc15a1a) mRNA expression levels in zebrafish adult tissues/organs and embryonic/early larval developmental stages. As assessed by expression in Xenopus laevis oocytes and two-electrode voltage clamp measurements, zebrafish PepT1a, as PepT1b, is electrogenic, Na+-independent, and pH-dependent and functions as a low-affinity system, with K0.5 values for Gly-Gln at − 60 mV of 6.92 mmol/L at pH 7.6 and 0.24 mmol/L at pH 6.5 and at − 120 mV of 3.61 mmol/L at pH 7.6 and 0.45 mmol/L at pH 6.5. Zebrafish pept1a mRNA is highly expressed in the intestine and ovary of the adult fish, while its expression in early development undergoes a complex trend over time, with pept1a mRNA being detected 1 and 2 days post-fertilization (dpf), possibly due to its occurrence in the RNA maternal pool, decreasing at 3 dpf (~ 0.5-fold) and increasing above the 1–2 dpf levels at 4 to 7 dpf, with a peak (~ 7-fold) at 6 dpf. Conclusions: We show that the zebrafish PepT1a-type transporter is functional and co-expressed with pept1b (slc15a1b) in the adult fish intestine. Its expression is also confirmed during the early phases of development when the yolk syncytial layer is present and yolk protein resorption processes are active. While completing the missing information on PepT1-type transporters function in the zebrafish, these results open to future investigations on the similar/differential role(s) of PepT1a/PepT1b in zebrafish and teleost fish physiology.publishedVersio

Conocimientos y prácticas sobre prevención de dengue en un Distrito de Lambayeque, Perú, 2015

Objetivo: Describir los conocimientos y prácticas respecto a las medidas preventivas de dengue en la persona responsable del cuidado de la vivienda en el centro poblado Batangrande. Material y Métodos: Se realizó una investigación de tipo cuantitativa con diseño descriptivo de corte transversal. Como técnica de recolección de datos se utilizó la entrevista y como instrumento el cuestionario, el cual va dirigido de forma específica a las variables que se pretenden estudiar en la presente investigación. Resultados: Se realizaron 345 visitas en total, de las cuales 15 de las viviendas se encontraron cerradas quedando finalmente 330 viviendas que fueron entrevistadas. En cuanto a conocimientos sobre dengue, 96 (29,1%) personas manifestaron conocer la enfermedad. En relación a medidas higiénicas para eliminar criaderos del zancudo, 5,2% (17) señalaron que conocen dichas medidas, mientras que 0,6% (2) reconocieron que medidas tomar para evitar ser picado por el mosquito del dengue. De las prácticas evaluadas más destacadas para prevenir el dengue en las personas entrevistadas y que se encuentran por encima del 50% son aquellas que eliminan aguas estancadas y la colocación de abate. Conclusiones: Los conocimientos sobre dengue son escasos, y existe un porcentaje aceptable de prácticas adecuadas

LIVER BIOCHEMISTRY PROFILE IN WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) REARED IN CAPTIVITY

El presente estudio se llevó a cabo con 23 venados cola blanca (Odocoileus virginianus), de ambos sexos, y criados en cautiverio en la provincia de Lima, con el objetivo de determinar el perfil bioquímico sanguíneo hepático a través de los valores séricos de Bilirrubina Total y Directa, Proteínas Totales, Albúmina, Alanino Amino Transferasa (ALT), Aspartato Amino Transferasa (AST), Fosfatasa Alcalina (FA), y Gamma Glutamil Transferasa (GGT). Los animales (7 machos y 16 hembras), pertenecientes a tres zoológicos o zoocriaderos, fueron anestesiados con clorhidrato de ketamina o con la combinación de clorhidrato de ketamina y clorhidrato de xilacina. Se extrajo 7 ml de sangre por punción de la vena safena en tubos estériles sin anticoagulante, y los sueros fueron analizados con kits comerciales. Los valores encontrados (media ± DE) fueron para Bilirrubina Total: 0.6 ± 0.3 mg/dl; Bilirrubina Directa: 0.08 ± 0.06 mg/dl; Proteínas Totales: 6.6 ± 0.7 g/dl; Albúmina: 3.6 ± 0.5 g/dl; ALT: 26.0 ± 9.7 UI/l; AST: 87.6 ± 22.9 UI/l; FA: 73.9 ± 33.8 UI/l; y GGT: 42.5 ± 12.6 UI/l. No hubo diferencia estadística entre sexos con excepción de BT y albúmina (p<0.05).This study was carried out with 23 adult white-tailed deer (Odocoileus virginianus)of both sexes, kept in captivity in the province of Lima to establish reference liverbiochemistry profilevalues (Total and direct bilirubin, total protein, albumin, alanineamino transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (AF),and gamma glutamyl transferase (GGT). The animals (7 males and 16 females) were from three local zoos and were anesthesyzed with ketamine hydrochloride or with acombination of ketamine hydrochloride and xylazine hydrochloride. Blood samples (7ml) were collected from the saphenous vein in sterile tubes and serum was analyzedusing commercial kits. The values (mean ± SD) were Total Bilirubin: 0.6 ± 0.3 mg/dl;Direct Bilirubin: 0.08 ± 0.06 mg/dl; Total Protein: 6.6 ± 0.7 g/dl; Albumin: 3.6 ± 0.5 g/dl;ALT: 26.0 ± 9.7 UI/l; AST: 87.6 ± 22.9 UI/l; AF: 73.9 ± 33.8 UI/l, and GGT: 42.5 ± 12.6 UI/l.There were no statistical differences due to sex except for total bilirubin and albumin(p<0.05