6,844 research outputs found

    The formation of voids in a universe with cold dark matter and a cosmological constant

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    A spherical Lagrangian hydrodynamical code has been written to study the formation of cosmological structures in the early Universe. In this code we take into account the presence of collisionless non-baryonic cold dark matter (CDM), the cosmological constant and a series of physical processes present during and after the recombination era, such as photon drag resulting from the cosmic background radiation and hydrogen molecular production. We follow the evolution of the structure since the recombination era until the present epoch. As an application of this code we study the formation of voids starting from negative density perturbations which evolved during and after the recombination era. We analyse a set of COBE-normalized models, using different spectra to see their influence on the formation of voids. Our results show that large voids with diameters ranging from 10h^{-1} Mpc up to 50h^{-1} Mpc can be formed in a universe model dominated by the cosmological constant (\Omega_\Lambda ~ 0.8). This particular scenario is capable of forming large and deep empty regions (with density contrasts \delta < -0.6). Our results also show that the physical processes acting on the baryonic matter produce a transition region where the radius of the dark matter component is greater than the baryonic void radius. The thickness of this transition region ranges from about tens of kiloparsecs up to a few megaparsecs, depending on the spectrum considered. Putative objects formed near voids and within the transition region would have a different amount of baryonic/dark matter when compared with \Omega_b/\Omega_d. If one were to use these galaxies to determine, by dynamical effects or other techniques, the quantity of dark matter present in the Universe, the result obtained would be only local and not representative of the Universe as a whole.Comment: MNRAS (in press); 9 pages, no figure

    Memoria de los actos del Poder Ejecutivo en los ramos de Relaciones Exteriores y Justicia correspondiente al año de 1939 presentada a la honorable Asamblea Nacional Legislativa por el ministro de las carteras Dr. Miguel Ángel Araujo, el 5 de marzo de 1940

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    Contenido: Ramo de Relaciones Exteriores. -- Sección Diplomatica: Centro America,Latino America, Estados Unidos de America, Unión Panamericana,Europa, Santa Sede,Asia,Sociedad de las Naciones, Misiones diplomaticas de El salvador, misiones diplomáticas extranjeras. --Reuniones internacionales. --Sección consular. --Ramo de Justicia. --Suplicatorias. --Conmutaciones. --Acuerdos y decretos legislativos. --Movimiento judicial,Corte Suprema de Justicia. --Camara de Tercera Instancia. --Camara de Segunda Instancia de la segunda sección del centro. --Camara de la segunda instancia de lo civil de la primera sección del centro. --Camara de segunda instancia de la tercera sección del centro. --Camara de segunda instancia de la cuarta sección del centro. --Camara de segunda instancia de la sección de occidente. --Juzgado general de Hacienda. --Registro de la Propiedad Raiz e Hipotecas

    Gene surgery

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    Gene therapy became in last decade a new emerging therapeutic era showing promising results against different diseases such as cancer, cardiovascular diseases, diabetes, and neurological disorders. Recently, the genome editing technique for eukaryotic cells called CRISPR-Cas (Clustered Regulatory Interspaced Short Palindromic Repeats) has enriched the field of gene surgery with enhanced applications. In the present review, we summarized the different applications of gene surgery for treating human diseases such as cancer, diabetes, nervous, and cardiovascular diseases, besides the molecular mechanisms involved in these important effects. Several studies support the important therapeutic applications of gene surgery in a large number of health disorders and diseases including β-thalassemia, cancer, immunodeficiencies, diabetes, and neurological disorders. In diabetes, gene surgery was shown to be effective in type 1 diabetes by triggering different signaling pathways. Furthermore, gene surgery, especially that using CRISPR-Cas possessed important application on diagnosis, screening and treatment of several cancers such as lung, liver, pancreatic and colorectal cancer. Nevertheless, gene surgery still presents some limitations such as the design difficulties and costs regarding ZFNs (Zinc Finger Nucleases) and TALENs (Transcription Activator-Like Effector Nucleases) use, off-target effects, low transfection efficiency, in vivo delivery-safety and ethical issues

    The Roosevelt – Rondon expedition marmoset (Mico marcai) : unveiling the conservation status of a data deficient species

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    The Roosevelt-Rondon Expedition marmoset, Mico marcai, was collected in 1914 and to date, all information on this species comes from three skins brought back by the Expedition and two additional skins collected in the 1990s. It is no surprise then that M.marcai has been classified as Data Deficient (DD). Given that Mico marcai’s suspected range sits on the path of the advancing Brazilian “Arc-of-Deforestation”, it is urgent that relevant data be collected to assess this taxon. Here we present the first comprehensive field data on the distribution, population size and threats on M. marcai with the goal of removing the species from the DD category. From 2012 to 2015, we surveyed for the species in 11 localities, in and around the Marmelos-Aripuanã interfluve, and estimated density using distance sampling on 10 transects. We also used spatial predictive modelling to project the amount of habitat that will be lost within its range in 18 years under different deforestation scenarios. We found marmosets in 14 localities and calculated its Extent of Occurrence to be 31,073 km2. We walked 271 km and detected 30 marmoset groups, allowing us to estimate their density to be 8.31 individuals/km2 and a total population of 258,217.71 individuals. By a “Business as usual” scenario, 20,181 km2 of habitat will be lost in three marmoset generations (~18 years), compromising 33% of the species’ range. Accordingly, M. marcai should be classified as globally Vulnerable under category A3c. Following our study, we propose the Amazonian marmosets, genus Mico, should undergo similar re-assessment as their ranges all fall in the path of the Arc-of-Deforestation. Keywords: Amazonian marmosets, Conservation Status, Data Deficient, Habitat Loss, Southern Amazoni

    Controlling the Trade-Off between Resource Efficiency and User Satisfaction in NDNs Based on Naïve Bayes Data Classification and Lagrange Method

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    [EN] This paper addresses the fundamental problem of the trade-off between resource efficiency and user satisfaction in the limited environments of Named Data Networks (NDNs). The proposed strategy is named RADC (Resource Allocation based Data Classification), which aims at managing such trade-off by controlling the system's fairness index. To this end, a machine learning technique based on Multinomial Naive Bayes is used to classify the received contents. Then, an adaptive resource allocation strategy based on the Lagrange utility function is proposed. To cache the received content, an adequate content placement and a replacement mechanism are enforced. Simulation at the system level shows that this strategy could be a powerful tool for administrators to manage the trade-off between efficiency and user satisfaction.This work is derived from R&D project RTI2018-096384-B-I00, funded by MCIN/AEI/ 10.13039/501100011033 and "ERDF A way of making Europe".Herouala, AT.; Kerrache, CA.; Ziani, B.; Tavares De Araujo Cesariny Calafate, CM.; Lagraa, N.; Tahari, AEK. (2022). Controlling the Trade-Off between Resource Efficiency and User Satisfaction in NDNs Based on Naïve Bayes Data Classification and Lagrange Method. Future Internet. 14(2):1-14. https://doi.org/10.3390/fi1402004811414

    Dynamic studies of biomimetic coated polycaprolactone nanofiber meshes as bone extracellular matrix analogues

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    This work aimed at studying the effects of dynamic culture conditions and biomimetic coating on bone cells grown on nanofiber meshes. In our previous work, biomimetic calcium phosphate coated polycaprolactone nanofibre meshes (BCP-NM) proved to be more efficient for supporting cell attachment and proliferation under static conditions, when compared to polycaprolactone nanofibre meshe (PCL-NM). However, no studies on the influence of bioreactors on the behaviour of cells cultivated on these materials were developed so far. [...]info:eu-repo/semantics/publishedVersio

    Comparison between different droop based control techniques and a virtual control oscillator

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    This work presents a literature review about control techniques for parallel connected power inverters under microgrid applications. Some control strategies, based on droop control for parallel inverters of distributed generation units in an ac distribution system will be presented in this work. Finally, an important method called Virtual Oscillating Control (VOC) is suggested for connecting voltage source inverters. Inverters are able to work in parallel with a constant-voltage constant frequency system, as well as with other inverters and also in standalone operation. The different power sources can share the load also under unbalanced conditions. Throughout this work several simulation results are presented in order to demonstrate the behaviour the behavior of the different control strategies tested.Peer ReviewedPostprint (published version

    Performance and carcass traits of heifers Rubia Gallega x Nellore supplemented with chromium picolinate

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    The objective was to evaluate the productive performance and the carcass traits of Nellore (NEL) and Rubia Gallega x Nellore F1 (NRG) heifers, subjected to energy-protein supplementation with chromium picolinate (CrP). Sixty heifers (30 NEL and 30 NRG) with a mean initial adjusted body weight (BW) of 214.50 kg and mean age of 201 days were distributed into a completely randomized design, in a 2 x 2 factorial (2 genetic groups x 2 supplementation groups). The experimental period lasted 320 days. There was no interaction (p&gt;0.05) between the genetic groups and the supplements. The addition of CrP to the supplement did not alter the performance and carcass characteristics evaluated (p&gt;0.05). However, the NRG genetic group was better than the NEL in the performance characteristics as final live weight, mean daily gain and carcass yield as carcass yield, Muscularity (p≤0.05).The use of the Rubia Gallega genotype in crossbreeding provides an increase in production of heavier carcasses with lower fat percentages and higher yields when compared to the use of Nellore heifers.The objective was to evaluate the productive performance and the carcass traits of Nellore (NEL) and Rubia Gallega x Nellore F1 (NRG) heifers, subjected to energy-protein supplementation with chromium picolinate (CrP). Sixty heifers (30 NEL and 30 NRG) with a mean initial adjusted body weight (BW) of 214.50 kg and mean age of 201 days were distributed into a completely randomized design, in a 2 x 2 factorial (2 genetic groups x 2 supplementation groups). The experimental period lasted 320 days. There was no interaction (p&gt;0.05) between the genetic groups and the supplements. The addition of CrP to the supplement did not alter the performance and carcass characteristics evaluated (p&gt;0.05). However, the NRG genetic group was better than the NEL in the performance characteristics as final live weight, mean daily gain and carcass yield as carcass yield, Muscularity (p≤0.05).The use of the Rubia Gallega genotype in crossbreeding provides an increase in production of heavier carcasses with lower fat percentages and higher yields when compared to the use of Nellore heifers
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