A single model of traversable wormholes supported by generalized phantom energy or Chaplygin gas

This paper discusses a new variable equation of state parameter leading to exact solutions of the Einstein field equations describing traversable wormholes. In addition to generalizing the notion of phantom energy, the equation of state generates a mathematical model that combines the generalized phantom energy and the generalized Chaplygin gas models.Comment: 6 pages, no figure

Nota corta. Análisis de heterogeneidad entre aislados de Mycoplasma pullorum por medio de técnicas de amplificación de DNA polimórfico

Mycoplasmas were isolated from chickens with respiratory problems during field investigations of a concentrated respiratory disease outbreak in western Cuba, 1997. A high percentage of mycoplasma cultures from tracheas and air-sac lesions yielded pure cultures of Mycoplasma pullorum. The aim of the present work was to investigate the heterogeneity among M. pullorum isolates from Cuba and strains from other countries using random amplified polymorphic DNA (RAPD) techniques. The results show that the RAPD method may be a useful identification tool for studying the epidemiology of poultry mycoplasmosis in Cuba.En 1997 se aislaron micoplasmas en el curso de investigaciones de campo en pollos con un brote de enfermedad respiratoria localizada en la zona oeste de Cuba. Un alto porcentaje de los cultivos de micoplasmas procedentes de lesiones de tráquea y alveolos revelaron la presencia de Mycoplasma pullorum. El objetivo de este trabajo fue investigar la heterogeneidad de los aislados cubanos entre sí y con cepas de otros países, mediante la técnica RAPD (DNA polimórfico amplificado al azar). Los resultados muestran que la técnica RAPD puede ser una herramienta de identificación útil en el estudio de la epidemiología de la micoplasmosis aviar en Cuba

Benefits of probiotic administration on growth and performance along metamorphosis and weaning of Senegalese sole (Solea senegalensis)

Suitable nutrition at first feeding in marine fish larvae is an important factor for successful larval and juvenile rearing. In this way probiotic supplementation may contribute to better face the habitual stress of metamorphosis and weaning at early sole stages. The aimof this study was to optimize Shewanella putrefaciens Pdp11 administration to Senegalese sole (Solea senegalensis) at early stages of development. For this purpose, we studied the influence of a short pulse of S. putrefaciens Pdp11 (10–30 dah) on growth performance, gut microbiota modulation, digestive enzymes activities and body composition. These probiotic bacteria were incorporated using Artemia as live vector (2.5 × 10 7 cfu mL −1 ) and supplied to sole specimens in a co-feeding regime (Gemma, Skretting) by triplicate. S. putrefaciens Pdp11 colonized larval gut being present from23 to 119 dah. Probiotic supply significantly modulated larval and fry gut microbiota. A PCA analysis including all the parameters analyzed strongly associated S. putrefaciens Pdp11 presence with a higher fish growth, a higher digestive proteolytic activity level and a fish body composition modulation along S. senegalensis rearing. In addition less size variability was obtained frommetamorphosis until the end of weaning. In conclusion a short pulse of S. putrefaciens Pdp11 (10– 30 dah) seems sufficient to obtain a suitable microbial modulation involved in a better growth performance and body composition that suggests a great potential for sole aquaculture production.En prens

Modulation of the intestinal microbiota and expression of gene of senegalese sole (Solea senegalensis, Kaup 1858) after dietary administration of oxytetracycline.

Oxitetracycline and probiotics (Pdp11) administration to sole juveniles showed important changes in the species composition of intestinal microbiota that established a relationship between these species and gene expression

Changes in intestinal microbiota and gene expression of immune system parameters caused by dietary administration of alginate and Shewanella putrefaciens Pdp11 in Senegalese sole (Solea senegalensis Kaup, 1858) specimens

Dietary administration of sodium alginate single or mixed with Pdp11 modulated the intestinal microbiota diversity of sole juveniles. Both treatments promoted a change in the species present in the gut in comparison with control group. In addition, oral administration of alginate promoted the appearance of an intestinal microbiota highly influenced by the prebiotic presence. Synbiotic administration of alginate with Pdp11 promoted a more pronounced decreasing in the similarity index and in the species richness. Both treatments modulated the expression of genes related with immune system functions

Measurement of black carbon emissions from multiple engine and source types using laser-induced incandescence : sensitivity to laser fluence

A new regulatory standard for non-volatile particulate matter (nvPM) mass-based emissions from aircraft engines has been adopted by the International Civil Aviation Organisation. One of the instruments used for the regulatory nvPM mass emissions measurements in aircraft engine certification tests is the Artium Technologies LII 300, which is based on laser-induced incandescence. The LII 300 response has been shown in some cases to vary with the type of black carbon particle measured. Hence it is important to identify a suitable black carbon emission source for instrument calibration. In this study, the relationship between the nvPM emissions produced by different engine sources and the response of the LII 300 instrument utilising the auto-compensating laser-induced incandescence (AC-LII) method was investigated. Six different sources were used, including a turboshaft helicopter engine, a diesel generator, an intermediate pressure test rig of a single-sector combustor, an auxiliary power unit gas turbine engine, a medium-sized diesel engine, and a downsized turbocharged direct-injection gasoline engine. Optimum LII 300 laser fluence levels were determined for each source and operating condition evaluated. It was found that an optimised laser fluence can be valid for real-time measurements from a variety of sources, where the mass concentration was independent of laser fluence levels covering the typical operating ranges for the various sources. However, it is important to perform laser fluence sweeps to determine the optimum fluence range as differences were observed in the laser fluence required between sources and fuels. We discuss the measurement merits, variability, and best practices in the real-time quantification of nvPM mass concentration using the LII 300 instrument and compare that with other diagnostic techniques, namely absorption-based methods such as photoacoustic spectroscopy (using a photoacoustic extinctiometer, PAX, and a micro soot sensor, MSS) and thermal-optical analysis (TOA). Particle size distributions were also measured using a scanning mobility particle sizer (SMPS). Overall, the LII 300 provides robust and consistent results when compared with the other diagnostic techniques across multiple engine sources and fuels. The results from this study will inform the development of updated calibration protocols to ensure repeatable and reproducible measurements of nvPM mass emissions from aircraft engines using the LII 300

Constraints on coupling constant between dark energy and dark matter

We have investigated constraints on the coupling between dark matter and the interacting Chaplygin gas. Our results indicate that the coupling constant $c$ between these two entities can take arbitrary values, which can be either positive or negative, thus giving arbitrary freedom to the inter-conversion between Chaplygin gas and dark matter. Thus our results indicate that the restriction $0<c<1$ on the coupling constant occurs as a very special case. Our analysis also supports the existence of phantom energy under certain conditions on the coupling constant.Comment: 16 Pages, 3 figure

The treatment with the probiotic Shewanella putrefaciens Pdp11 of sepecimens of Solea senegalensis exposed to high stocking densities to enhance their resistance to disease

Aquaculture industry exposes fish to acute stress events, such as high stocking density, and a link between stress and higher susceptibility to diseases has been concluded. Several studies have demonstrated increased stress tolerance of fish treated with probiotics, but the mechanisms involved have not been elucidated. Shewanella putrefaciens Pdp11 is a strain isolated from healthy gilthead seabream (Sparus aurata L.) and it is considered as probiotics. The aim of this study was to evaluate the effect of the dietary administration of this probiotics on the stress tolerance of Solea senegalensis specimens farmed under high stocking density (PHD) compared to a group fed a commercial diet and farmed under the same conditions (CHD). In addition, during the experiment, a natural infectious outbreak due to Vibrio species affected fish farmed under crowding conditions. Changes in the microbiota and histology of intestine and in the transcription of immune response genes were evaluated at 19 and 30 days of the experiment. Mortality was observed after 9 days of the beginning of the experiment in CHD and PHD groups, it being higher in the CHD group. Fish farmed under crowding stress showed reduced expression of genes at 19 day probiotic feeding. On the contrary, a significant increase in immune related gene expression was detected in CHD fish at 30 day, whereas the gene expression in fish from PHD group was very similar to that showed in specimens fed and farmed with the conventional conditions. In addition, the dietary administration of S. putrefaciens Pdp11 produced an important modulation of the intestinal microbiota, which was significantly correlated with the high number of goblet cells detected in fish fed the probiotic diet.Postprin