787 research outputs found
Comportamiento de hormigones de alta resistencia con fibras de acero frente al impacto de proyectiles
Este trabajo presenta los resultados de la investigación llevada a cabo por los autores sobre el comportamiento de hormigón de 80 MPa de resistencia característica a compresión reforzado con diferentes cuantías de fibras de acero de alto contenido en carbono sometido al impacto de proyectiles de distintos calibres, determinando el espesor de muros de este tipo de hormigón que sería preciso disponer para impedir su perforación por dichos proyectiles, así como los valores máximos de penetración, para que en el caso de no producirse perforación y sólo penetración, no se genera cráter, “scabbing”, en el trasdós de los mismos. Previamente a los ensayos balísticos fue preciso diseñar los hormigones para que, presentaran determinadas características mecánicas, especialmente las relacionadas con la ductilidad, dado que estos hormigones especiales deben absorber la elevada energía que le transmiten los proyectiles y las ondas de choque que los acompañan
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Transcriptomic Profiles of Monocyte-Derived Macrophages in Response to Escherichia coli is Associated with the Host Genetics.
Reactive Nitrogen Species (RNS) are a group of bactericidal molecules produced by macrophages in response to pathogens in a process called oxidative burst. Nitric oxide (NO-) is a member of RNS produced from arginine by inducible Nitric Oxide Synthase (iNOS) enzyme. The activity of iNOS and production of NO- by macrophages following stimulation is one of the indicators of macrophage polarization towards M1/proinflammatory. Production of NO- by bovine monocyte-derived macrophage (MDM) and mouse peritoneal macrophages has been shown to be strongly associated with host genetic with the heritability of 0.776 in bovine MDM and 0.8 in mouse peritoneal macrophages. However, the mechanism of genetic regulation of macrophage response has remained less explored. In the current study, the transcriptome of bovine MDMs was compared between two extreme phenotypes that had been classified as high and low responder based on NO- production. The results showed that 179 and 392 genes were differentially expressed (DE) between high and low responder groups at 3 and 18 hours after exposure to Escherichia coli, respectively. A set of 11 Transcription Factors (TFs) (STAT1, IRF7, SPI1, STAT4, IRF1, HIF1A, FOXO3, REL, NFAT5, HIC1, and IRF4) at 3 hours and a set of 13 TFs (STAT1, IRF1, HIF1A, STAT4, ATF4, TP63, EGR1, CDKN2A, RBL1, E2F1, PRDM1, GATA3, and IRF4) at 18 hours after exposure to E. coli were identified to be differentially regulated between the high and low responder phenotypes. These TFs were found to be divided into two clusters of inflammatory- and hypoxia-related TFs. Functional analysis revealed that some key canonical pathways such as phagocytosis, chemotaxis, antigen presentation, and cell-to-cell signalling are enriched among the over-expressed genes by high responder phenotype. Based on the results of this study, it was inferred that the functional characteristics of bovine MDMs are associated with NO-based classification. Since NO- production is strongly associated with host genetics, this study for the first time shows the distinct proinflammatory profiles of macrophages are controlled by the natural genetic polymorphism in an outbred population. In addition, the results suggest that genetics can be considered as a new dimension in the current model of macrophage polarization which is currently described by the combination of stimulants, only
An Upper Limit on the Mass of the Circumplanetary Disk for DH Tau b
Indexación: Scopus.DH Tau is a young (sim;1 Myr) classical T Tauri star. It is one of the few young PMS stars known to be associated with a planetary mass companion, DH Tau b, orbiting at large separation and detected by direct imaging. DH Tau b is thought to be accreting based on copious Ha emission and exhibits variable Paschen Beta emission. NOEMA observations at 230 GHz allow us to place constraints on the disk dust mass for both DH Tau b and the primary in a regime where the disks will appear optically thin. We estimate a disk dust mass for the primary, DH Tau A of 17.2 ± 1.7 MÅ, which gives a disk to star mass ratio of 0.014 (assuming the usual gas to dust mass ratio of 100 in the disk). We find a conservative disk dust mass upper limit of 0.42M⊕ for DH Tau b, assuming that the disk temperature is dominated by irradiation from DH Tau b itself. Given the environment of the circumplanetary disk, variable illumination from the primary or the equilibrium temperature of the surrounding cloud would lead to even lower disk mass estimates. A MCFOST radiative transfer model, including heating of the circumplanetary disk by DH Tau b and DH Tau A, suggests that a mass-averaged disk temperature of 22 K is more realistic, resulting in a dust disk mass upper limit of 0.09M⊕ for DH Tau b. We place DH Tau b in context with similar objects and discuss the consequences for planet formation models.http://iopscience.iop.org/article/10.3847/1538-3881/aa74cd/met
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Deducing signaling pathways from parallel actions of arsenite and antimonite in human epidermal keratinocytes.
Inorganic arsenic oxides have been identified as carcinogens in several human tissues, including epidermis. Due to the chemical similarity between trivalent inorganic arsenic (arsenite) and antimony (antimonite), we hypothesized that common intracellular targets lead to similarities in cellular responses. Indeed, transcriptional and proteomic profiling revealed remarkable similarities in differentially expressed genes and proteins resulting from exposure of cultured human epidermal keratinocytes to arsenite and antimonite in contrast to comparisons of arsenite with other metal compounds. These data were analyzed to predict upstream regulators and affected signaling pathways following arsenite and antimonite treatments. A majority of the top findings in each category were identical after treatment with either compound. Inspection of the predicted upstream regulators led to previously unsuspected roles for oncostatin M, corticosteroids and ephrins in mediating cellular response. The influence of these predicted mediators was then experimentally verified. Together with predictions of transcription factor effects more generally, the analysis has led to model signaling networks largely accounting for arsenite and antimonite action. The striking parallels between responses to arsenite and antimonite indicate the skin carcinogenic risk of exposure to antimonite merits close scrutiny
Critical objective size and calmness modulus in linear programming
This paper introduces the concept of critical objective size associated with
a linear program in order to provide operative point-based formulas (only
involving the nominal data, and not data in a neighborhood) for computing or
estimating the calmness modulus of the optimal set (argmin) mapping under
uniqueness of nominal optimal solution and perturbations of all
coefficients. Our starting point is an upper bound on this modulus given in
\cite{CHPTmp}. In this paper we prove that this upper bound is attained if
and only if the norm of the objective function coefficient vector is less
than or equal to the critical objective size. This concept also allows us to
obtain operative lower bounds on the calmness modulus. We analyze in detail
an illustrative example in order to explore some strategies that can improve
the referred upper and lower bounds
Seguimiento de la evolución de los niveles de salinidad y nitratos en el acuífero superficial de Zafarraya y en fincas de hortícolas al aire libre
La horticultura al aire libre del Llano de Zafarraya es el motor económico de la
comarca. El riego de este sector se sustenta en el sistema acuífero del Polje de Zafarraya y
Sierra Gorda. En estos acuíferos, como consecuencia de la explotación agrícola de la zona,
se viene produciendo desde hace décadas sobreexplotación del recurso, con la consiguiente
salinización y nitrificación. Los objetivos de este trabajo han sido estudiar los niveles de
salinidad y nitratos de las aguas del acuífero de Zafarraya y hacer un seguimiento de la
solución del suelo en explotaciones hortícolas de la zona, para poder realizar
recomendaciones que permitan mejorar la gestión de la fertilización y evitar el aumento de la
contaminación por nitratos. Los niveles de salinidad obtenidos a lo largo del periodo de
estudio han sido estables y no representan problemas para los principales cultivos hortícolas
de la zona. En lo que respecta a la concentración de nitratos, los resultados muestran
niveles excesivos por encima de 300 mg L-1. Estos resultados son consecuencia de la
práctica habitual de aplicaciones excesivas de fertilizantes nitrogenados. La recomendación
inicial sería mantener una concentración de nitratos estable a lo largo del ciclo de cultivo
para evitar acumulaciones en el suelo sobre todo al final del mismo
Nitric oxide in fungi: is there NO light at the end of the tunnel?
Nitric oxide (NO) is a remarkable gaseous molecule with multiple and important roles in different organisms, including fungi. However, the study of the biology of NO in fungi has been hindered by the lack of a complete knowledge on the different metabolic routes that allow a proper NO balance, and the regulation of these routes. Fungi have developed NO detoxification mechanisms to combat nitrosative stress, which have been mainly characterized by their connection to pathogenesis or nitrogen metabolism. However, the progress on the studies of NO anabolic routes in fungi has been hampered by efforts to disrupt candidate genes that gave no conclusive data until recently. This review summarizes the different roles of NO in fungal biology and pathogenesis, with an emphasis on the alternatives to explain fungal NO production and the recent findings on the involvement of nitrate reductase in the synthesis of NO and its regulation during fungal development
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Comparison of five different RNA sources to examine the lactating bovine mammary gland transcriptome using RNA-Sequencing.
The objective of this study was to examine five different sources of RNA, namely mammary gland tissue (MGT), milk somatic cells (SC), laser microdissected mammary epithelial cells (LCMEC), milk fat globules (MFG) and antibody-captured milk mammary epithelial cells (mMEC) to analyze the bovine mammary gland transcriptome using RNA-Sequencing. Our results provide a comparison between different sampling methods (invasive and non-invasive) to define the transcriptome of mammary gland tissue and milk cells. This information will be of value to investigators in choosing the most appropriate sampling method for different research applications to study specific physiological states during lactation. One of the simplest procedures to study the transcriptome associated with milk appears to be the isolation of total RNA directly from SC or MFG released into milk during lactation. Our results indicate that the SC and MFG transcriptome are representative of MGT and LCMEC and can be used as effective and alternative samples to study mammary gland expression without the need to perform a tissue biopsy
Calmness of the Optimal Value in Linear Programming
This research has been partially supported by grant MTM2014-59179-C2-2-P from MINECO, Spain, and FEDER "Una manera de hacer Europa," European Union
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