381 research outputs found
Genome Sequence of a Novel Archaeal Fusellovirus Assembled from the Metagenome of a Mexican Hot Spring
The consensus genome sequence of a new member of the family Fuselloviridae designated as SMF1 (Sulfolobales Mexican fusellovirus 1) is presented. The complete circular genome was recovered from a metagenomic study of a Mexican hot spring. SMF1 exhibits an exceptional coding strand bias and a reduced set of fuselloviral core genes
Resonant interaction between gravitational waves, electromagnetic waves and plasma flows
In magnetized plasmas gravitational and electromagnetic waves may interact
coherently and exchange energy between themselves and with plasma flows. We
derive the wave interaction equations for these processes in the case of waves
propagating perpendicular or parallel to the plasma background magnetic field.
In the latter case, the electromagnetic waves are taken to be circularly
polarized waves of arbitrary amplitude. We allow for a background drift flow of
the plasma components which increases the number of possible evolution
scenarios. The interaction equations are solved analytically and the
characteristic time scales for conversion between gravitational and
electromagnetic waves are found. In particular, it is shown that in the
presence of a drift flow there are explosive instabilities resulting in the
generation of gravitational and electromagnetic waves. Conversely, we show that
energetic waves can interact to accelerate particles and thereby \emph{produce}
a drift flow. The relevance of these results for astrophysical and cosmological
plasmas is discussed.Comment: 12 pages, 1 figure, typos corrected and numerical example adde
Analysis of friction coefficient for a base steel 5 % Cr, applying variable loads of 196 N, 294 N and 392 N, and speeds of 0,18 m/sec, 0,36 m/sec and 0,54 m/sec
The present study consists in analyzing the friction coefficient as a variable of the normal load and slip speed for 5% Cr steel, by applying the Block-on-Disk method according to ASTM D2714. The friction coefficient increases linearly 23,25 % from 0,214 to 0,266 when the load is increased from 196 N to 392 N; the same phenomenon is observed when the friction coefficient increases 47,82 % from 0,23 to 0,34 when the slip speed increases from 0,18 m/sec to 0,54 m/sec. The friction coefficient increased by 23,25 % for an increase in the load from 196 N to 392 N, which corresponds to 100 %, while an increase of the friction coefficient of 47,82 % occurred by increasing the speed from 0,18 m/sec to 0,54 m/sec which corresponds to 200 %
Susceptibility of pepper weevil (anthonomus eugenii cano) (coleoptera: curculionidae) to seven insecticides in rural areas of Baja California Sur, México
The susceptibility of the pepper weevil (Anthonomus eugenii), collected from Baja California Sur, Mexico, to seven insecticides was determined. Acontact, residual exposition method was used to obtain the lethal concentrations fifty (LC50) and the diagnostic concentration (LC95) of organophosphates (OF), carbamates (CA), pyrethroids (PIR), and organochlorine (OC) insecticides used to control pepper weevils from two agricultural areas (Los Planes and Todos Santos) in Southern Baja California Peninsula, as well as on a pepper weevil population not exposed to insecticides (PWIF) for two years. The highest LC50’s were obtained for methomyl (CA) and oxamyl (CA), followed by methamidophos (OF), endosulfan (OC), cyfluthrin (PIR) and azinphos-methyl (OF). The lowest LC50’s were observed for carbaryl (CA). The field population from Todos Santos showed lower susceptibility than the population from Los Planes to insecticides as methomyl, oxamyl, and carbaryl, while with methamidophos, azinphos-methyl, and cyfluthrin, the LC50 showed higher values. The PWIF population presented the lowest LC50 values of all three populations tested. However, in most cases, the difference was not significant in relation to the two field populations, thus the PWIF population needs to be kept free of insecticides for longer periods to establish a susceptibility baseline for Anthonomus eugenii
Conservation and Sustainability of Mexican Caribbean Coral Reefs and the Threats of a Human-Induced Phase-Shift
Evaluación de compost a base de residuos de la industria azucarera con gallinaza y estiércol bovino
El uso de compost producido a base de residuos de industria azucarera y de la cría de animales es una alternativa para corregir la fertilidad del suelo, reciclar los nutrientes y minimizar procesos de contaminación por la deposición inadecuada de los mismos. El experimento tiene como objetivo evaluar dosis de compost a base de residuos de la industria azucarera como mejorador de las características químicas del suelo. El experimento tuvo un arreglo factorial, siendo los factores, tipos y dosis de compost. El compost fue a base de residuos de la industria azucarera con estiércol bovino (C-EB) y con gallinaza (C-G), las dosis evaluadas de compost fueron 0; 2,11; 4,23; 6,34; 8,45; 10,56; 12,68 t ha-1. El experimento se realizó en invernadero en la Facultad de Ciencias Agrarias utilizando macetas de 5 L con 7,1 kg de suelo. En los mismos fue sembrado trigo como planta indicadora, siendo dispuestos los tratamientos en bloques completos al azar. El experimento fue conducido por tres meses y el trigo por 60 días. Las mediciones en el trigo y en las propiedades químicas del suelo fueron sometidas a análisis de varianza. En las propiedades químicas del suelo el fósforo presentó diferencia significativas con la aplicación de compost (C-G), a dosis de 12,68 t ha-1 alcanzó un máximo de 21,22 mg kg-1 se ajustó a una ecuación lineal (y =1,4752x+0,9223) con coeficiente de determinación (R² = 96 %), que indicó un aumento por cada tonelada adicional de Gallinaza.; el magnesio presento diferencia entre los tipos de compost siendo superior en el compost (C-G); las variables de Ca+2, Mg+2, K+, conductividad eléctrica y pH no presentaron diferencias significativas. La materia seca área y radicular presentaron diferencias significativas para ambos compost, alcanzando un peso de 20,00 y 11,55g respectivamente con la aplicación de 8,45 t ha-1 de C-EB. En conclusión
los abonos orgánicos combinados con los residuos de la industria azucarera son una alternativa viable para la producción orgánicaFil: Bobadilla Galeano, Silvia P..
Universidad Nacional de Asunción (Paraguay)Fil: González, Alba L..
Universidad Nacional de Asunción (Paraguay)Fil: Leguizamón Rojas, Carlos A. .
Universidad Nacional de Asunción (Paraguay)Fil: Zacarias Servin, Doralicia.
Universidad Nacional de Asunción (Paraguay
Very high frequency gravitational wave background in the universe
Astrophysical sources of high frequency gravitational radiation are
considered in association with a new interest to very sensitive HFGW receivers
required for the laboratory GW Hertz experiment. A special attention is paid to
the phenomenon of primordial black holes evaporation. They act like black body
to all kinds of radiation, including gravitons, and, therefore, emit an
equilibrium spectrum of gravitons during its evaporation. Limit on the density
of high frequency gravitons in the Universe is obtained, and possibilities of
their detection are briefly discussed.Comment: 14 page
Gravitational wave detection using electromagnetic modes in a resonance cavity
We present a proposal for a gravitational wave detector, based on the
excitation of an electromagnetic mode in a resonance cavity. The mode is
excited due to the interaction between a large amplitude electromagnetic mode
and a quasi-monochromatic gravitational wave. The minimum metric perturbation
needed for detection is estimated to the order 7.10^(-23) using current data on
superconducting niobium cavities. Using this value together with different
standard models predicting the occurrence of merging neutron star or black hole
binaries, the corresponding detection rate is estimated to 1-20 events per
year, with a `table top' cavity of a few meters length.Comment: 8 pages, 1 figure, references adde
Genome-wide SNP profiling of worldwide goat populations reveals strong partitioning of diversity and highlights post-domestication migration routes
Background: Goat populations that are characterized within the AdaptMap project cover a large part of the worldwide distribution of this species and provide the opportunity to assess their diversity at a global scale. We analysed genome-wide 50 K single nucleotide polymorphism (SNP) data from 144 populations to describe the global patterns of molecular variation, compare them to those observed in other livestock species, and identify the drivers that led to the current distribution of goats. Results: A high degree of genetic variability exists among the goat populations studied. Our results highlight a strong partitioning of molecular diversity between and within continents. Three major gene pools correspond to goats from Europe, Africa and West Asia. Dissection of sub-structures disclosed regional gene pools, which reflect the main post-domestication migration routes. We also identified several exchanges, mainly in African populations, and which often involve admixed and cosmopolitan breeds. Extensive gene flow has taken place within specific areas (e.g., south Europe, Morocco and Mali-Burkina Faso-Nigeria), whereas elsewhere isolation due to geographical barriers (e.g., seas or mountains) or human management has decreased local gene flows. Conclusions: After domestication in the Fertile Crescent in the early Neolithic era (ca. 12,000 YBP), domestic goats that already carried differentiated gene pools spread to Europe, Africa and Asia. The spread of these populations determined the major genomic background of the continental populations, which currently have a more marked subdivision than that observed in other ruminant livestock species. Subsequently, further diversification occurred at the regional level due to geographical and reproductive isolation, which was accompanied by additional migrations and/or importations, the traces of which are still detectable today. The effects of breed formation were clearly detected, particularly in Central and North Europe. Overall, our results highlight a remarkable diversity that occurs at the global scale and is locally partitioned and often affected by introgression from cosmopolitan breeds. These findings support the importance of long-term preservation of goat diversity, and provide a useful framework for investigating adaptive introgression, directing genetic improvement and choosing breeding targets
Signatures of selection and environmental adaptation across the goat genome post-domestication
Background: Since goat was domesticated 10,000 years ago, many factors have contributed to the differentiation of goat breeds and these are classified mainly into two types: (i) adaptation to different breeding systems and/or purposes and (ii) adaptation to different environments. As a result, approximately 600 goat breeds have developed worldwide; they differ considerably from one another in terms of phenotypic characteristics and are adapted to a wide range of climatic conditions. In this work, we analyzed the AdaptMap goat dataset, which is composed of data from more than 3000 animals collected worldwide and genotyped with the CaprineSNP50 BeadChip. These animals were partitioned into groups based on geographical area, production uses, available records on solid coat color and environmental variables including the sampling geographical coordinates, to investigate the role of natural and/or artificial selection in shaping the genome of goat breeds. Results: Several signatures of selection on different chromosomal regions were detected across the different breeds, sub-geographical clusters, phenotypic and climatic groups. These regions contain genes that are involved in important biological processes, such as milk-, meat- or fiber-related production, coat color, glucose pathway, oxidative stress response, size, and circadian clock differences. Our results confirm previous findings in other species on adaptation to extreme environments and human purposes and provide new genes that could explain some of the differences between goat breeds according to their geographical distribution and adaptation to different environments. Conclusions: These analyses of signatures of selection provide a comprehensive first picture of the global domestication process and adaptation of goat breeds and highlight possible genes that may have contributed to the differentiation of this species worldwide
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