4,446 research outputs found

    Genome sequences of triacylglycerol metabolism in Rhodococcus as a platform for comparative genomics

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    Bacteria belonging to the Rhodococcus genus are usually able to synthesize and accumulate variable amounts of triacylglycerols (TAG) from diverse carbon sources. Although some significant advances in the basic knowledge on TAG metabolism in rhodococci have been made, the fundamental understanding of this process and its regulation remains to be clarified. The abundantly available genomic information for several rhodococcal species provides the possibility for comparative genome analysis on the occurrence and distribution of key genes and pathways involved in TAG metabolism. Our bioinformatic analyses of available databases from six rhodococcal strains demonstrated that genes/enzymes for reactions related to TAG biosynthesis and degradation, and fatty acid β-oxidation are surprisingly abundant in rhodococcal genomes. Several genes/enzymes of glycerolipids and fatty acid metabolism are highly represented in the analyzed genomes. A number of previously undescribed, new putative genes for glycerolipid metabolism in rhodococci have been identified and the size of each family has been estimated

    Effect of the non-stationarity of rainfall events on the design of hydraulic structures for runoff management and its applications to a case study at Gordo Creek watershed in Cartagena de Indias, Colombia

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    The 24-h maximum rainfall (P 24h-max ) observations recorded at the synoptic weather station of Rafael Núñez airport (Cartagena de Indias, Colombia) were analyzed, and a linear increasing trend over time was identified. It was also noticed that the occurrence of the rainfall value (over the years of record) for a return period of 10 years under stationary conditions (148.1 mm) increased, which evidences a change in rainfall patterns. In these cases, the typical stationary frequency analysis is unable to capture such a change. So, in order to further evaluate rainfall observations, frequency analyses of P 24h-max for stationary and non-stationary conditions were carried out (by using the generalized extreme value distribution). The goodness-of-fit test of Akaike Information Criterion (AIC), with values of 753.3721 and 747.5103 for stationary and non-stationary conditions respectively, showed that the latter best depicts the increasing rainfall pattern. Values of rainfall were later estimated for different return periods (2, 5, 10, 25, 50, and 100 years) to quantify the increase (non-stationary versus stationary condition), which ranged 6% to 12% for return periods from 5 years to 100 years, and 44% for a 2-year return period. The effect of these findings were tested in the Gordo creek watershed by first calculating the resulting direct surface runoff (DSR) for various return periods, and then modeling the hydraulic behavior of the downstream area (composed of a 178.5-m creek's reach and an existing box-culvert located at the watershed outlet) that undergoes flooding events every year. The resulting DSR increase oscillated between 8% and 19% for return periods from 5 to 100 years, and 77% for a 2-year return period when the non-stationary and stationary scenarios were compared. The results of this study shed light upon to the precautions that designers should take when selecting a design, based upon rainfall observed, as it may result in an underestimation of both the direct surface runoff and the size of the hydraulic structures for runoff and flood management throughout the city. © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license

    Metabolism of triacylglycerols in Rhodococcus species: insights from physiology and molecular genetics

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    Rhodococcus bacteria possess the ability to accumulate variable amounts of triacylglycerols (TAG) during growth on diverse carbon sources. The evolution seems to have selected these microorganisms as specialists in the accumulation of TAG among bacteria, since their biochemistry is efficiently designed for the biosynthesis and mobilization of these lipids. Detailed research of rhodococcal TAG metabolism started only a few years ago; thus, the fundamental understanding of this process and its regulation remains to be clarified. However, some interesting advances in the basic knowledge on TAG metabolism in rhodococci have been made. Most studies have focused on the physiology of TAG biosynthesis and mobilization in rhodococci. Only recently, some advances in molecular biology and genetics on TAG metabolism occurred as a result of the increasing available genomic information and the development of new genetic tools for rhodococci. These studies have been focused principally on some enzymes of TAG biosynthesis, such as the wax esters/diacylglycerolacyltransferases (WS/DGAT) and TAG granule-associated proteins. In this context, the most relevant achievements of basic research in the field have been summarized in this review article

    The two pion decay of the Roper resonance

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    We evaluate the two pion decay of the Roper resonance in a model where explicit re-scattering of the two final pions is accounted for by the use of unitarized chiral perturbation theory. Our model does not include an explicit ϵ\epsilon or σ\sigma scalar-isoscalar meson decay mode, instead it generates it dynamically by means of the pion re-scattering. The two ways, explicit or dynamically generated, of introducing this decay channel have very different amplitudes. Nevertheless, through interference with the other terms of the model we are able to reproduce the same phenomenology as models with explicit consideration of the ϵ\epsilon meson.Comment: 17 latex pages, 11 eps figures. A few misprints corrected. A few new references. Version accepted for publication in Phys. Rev.

    Diversity of HLA Class I and Class II blocks and conserved extended haplotypes in Lacandon Mayans.

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    Here we studied HLA blocks and haplotypes in a group of 218 Lacandon Maya Native American using a high-resolution next generation sequencing (NGS) method. We assessed the genetic diversity of HLA class I and class II in this population, and determined the most probable ancestry of Lacandon Maya HLA class I and class II haplotypes. Importantly, this Native American group showed a high degree of both HLA homozygosity and linkage disequilibrium across the HLA region and also lower class II HLA allelic diversity than most previously reported populations (including other Native American groups). Distinctive alleles present in the Lacandon population include HLA-A*24:14 and HLA-B*40:08. Furthermore, in Lacandons we observed a high frequency of haplotypes containing the allele HLA-DRB1*04:11, a relatively frequent allele in comparison with other neighboring indigenous groups. The specific demographic history of the Lacandon population including inbreeding, as well as pathogen selection, may have elevated the frequencies of a small number of HLA class II alleles and DNA blocks. To assess the possible role of different selective pressures in determining Native American HLA diversity, we evaluated the relationship between genetic diversity at HLA-A, HLA-B and HLA-DRB1 and pathogen richness for a global dataset and for Native American populations alone. In keeping with previous studies of such relationships we included distance from Africa as a covariate. After correction for multiple comparisons we did not find any significant relationship between pathogen diversity and HLA genetic diversity (as measured by polymorphism information content) in either our global dataset or the Native American subset of the dataset. We found the expected negative relationship between genetic diversity and distance from Africa in the global dataset, but no relationship between HLA genetic diversity and distance from Africa when Native American populations were considered alone

    Multi-site observations of Delta Scuti stars 7 Aql and 8 Aql (a new Delta Scuti variable): The twelfth STEPHI campaign in 2003

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    We present an analysis of the pulsation behaviour of the Delta Scuti stars 7 Aql (HD 174532) and 8 Aql (HD 174589) -- a new variable star -- observed in the framework of STEPHI XII campaign during 2003 June--July. 183 hours of high precision photometry were acquired by using four-channel photometers at three sites on three continents during 21 days. The light curves and amplitude spectra were obtained following a classical scheme of multi-channel photometry. Observations in different filters were also obtained and analyzed. Six and three frequencies have been unambiguously detected above a 99% confidence level in the range 0.090 mHz--0.300 mHz and 0.100 mHz-- 0.145 mHz in 7 Aql and 8 Aql respectively. A comparison of observed and theoretical frequencies shows that 7 Aql and 8 Aql may oscillate with p modes of low radial orders, typical among Delta Scuti stars. In terms of radial oscillations the range of 8 Aql goes from n=1 to n=3 while for 7 Aql the range spans from n=4 to n=7. Non-radial oscillations have to be present in both stars as well. The expected range of excited modes according to a non adiabatic analysis goes from n=1 to n=6 in both stars.Comment: 8 pages, 7 fugures, 5 tables, accepted for publication in Astronomical Journa

    Investigación de mercados para Casa Herrera y Raicilla

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    El equipo de trabajo brindado por parte del ITESO, se encargó de ayudar a dar a conocer la marca CAT SOUTH, de igual manera desarrolló ideas para cambiar el etiquetado del destilado de raicilla, se modificó la fórmula de los RTD y apoyó al desarrollo de contenido en las redes sociales. Se realizaron dos estudios a lo largo del semestre, un focus group para la modificación y reacción de la fórmula de los RTDS ante el mercado meta y la aceptación de esta ante el público. Un estudio de neuromarketing con eye-tracking para la introducción a retail y la posición de estos mismos dentro de un lugar. El desarrollo de la etiqueta del destilado se hizo solo con propuestas de cómo podría ser y las tendencias para ayudar y recomendar con un experto (diseñador) sobre el tema.ITESO, A.C

    HADES RV Programme with HARPS-N at TNG. VII. Rotation and activity of M-Dwarfs from time-series high-resolution spectroscopy of chromospheric indicators

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    We aim to investigate the presence of signatures of magnetic cycles and rotation on a sample of 71 early M-dwarfs from the HADES RV programme using high-resolution time-series spectroscopy of the Ca II H & K and Halpha chromospheric activity indicators, the radial velocity series, the parameters of the cross correlation function and the V-band photometry. We used mainly HARPS-N spectra, acquired over four years, and add HARPS spectra from the public ESO database and ASAS photometry light-curves as support data, extending the baseline of the observations of some stars up to 12 years. We provide log(R'hk) measurements for all the stars in the sample, cycle length measurements for 13 stars, rotation periods for 33 stars and we are able to measure the semi-amplitude of the radial velocity signal induced by rotation in 16 stars. We complement our work with previous results and confirm and refine the previously reported relationships between the mean level of chromospheric emission, measured by the log(R'hk), with the rotation period, and with the measured semi-amplitude of the activity induced radial velocity signal for early M-dwarfs. We searched for a possible relation between the measured rotation periods and the lengths of the magnetic cycle, finding a weak correlation between both quantities. Using previous v sin i measurements we estimated the inclinations of the star's poles to the line of sight for all the stars in the sample, and estimate the range of masses of the planets GJ 3998 b and c (2.5 - 4.9 Mearth and 6.3 - 12.5 Mearth), GJ 625 b (2.82 Mearth), GJ 3942 b (7.1 - 10.0 Mearth) and GJ 15A b (3.1 - 3.3 Mearth), assuming their orbits are coplanar with the stellar rotation.Comment: 19 pages, 16 figures, 10 table
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