Modeling dust emission in PN IC 418

We investigated the infrared (IR) dust emission from PN IC 418, using a detailed model controlled by a previous determination of the stellar properties and the characteristics of the photoionized nebula, keeping as free parameters the dust types, amounts and distributions relative to the distance of the central star. The model includes the ionized region and the neutral region beyond the recombination front (Photodissociation region, or PDR), where the [OI] and [CII] IR lines are formed. We succeeded in reproducing the observed infrared emission from 2 to 200~\mm. The global energy budget is fitted by summing up contributions from big grains of amorphous carbon located in the neutral region and small graphite grains located in the ionized region (closer to the central star). Two emission features seen at 11.5 and 30~\mm are also reproduced by assuming them to be due to silicon carbide (SiC) and magnesium and iron sulfides (Mg$_x$Fe$_{1-x}$S), respectively. For this, we needed to consider ellipsoidal shapes for the grains to reproduce the wavelength distribution of the features. Some elements are depleted in the gaseous phase: Mg, Si, and S have sub-solar abundances (-0.5 dex below solar by mass), while the abundance of C+N+O+Ne by mass is close to solar. Adding the abundances of the elements present in the dusty and gaseous forms leads to values closer to but not higher than solar, confirming that the identification of the feature carriers is plausible. Iron is strongly depleted (3 dex below solar) and the small amount present in dust in our model is far from being enough to recover the solar value. A remaining feature is found as a residue of the fitting process, between 12 and 25~\mm, for which we do not have identification.Comment: Accepted for publication in Astronomy & Astrophysics. V2: adding reference

The Neuquén composite section: magnetostratigraphy and biostratigraphy of the marine lower Jurassic from the Neuquén basin (Argentina)

Paleomagnetic and biostratigraphic data from five marine sedimentary sections in the Argentine Neuquén basin have allowed to construct the Lower Jurassic Neuquén Composite Section. This composite section comprises 14 reversed and 11 normal polarity Zones, in relation to 17 Andean ammonite Assemblage Zones, spanning the Hettangian^Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower Jurassic marine successions in the Southern Hemisphere. The Neuquén composite Section was correlated to the International Mesozoic Polarity Time Scale which, for the Lower Jurassic, comprises 54 polarity Zones and 16 Standard ammonite Zones. The correlation between the regional and the international biomagnetostratigraphic scales supports but also refines the correlation between the Andean and Standard ammonite zonations. Correlation between the Neuquén composite Section and the polarity sequences recorded in each section helped to assign several unfossiliferous stratigraphical levels to the corresponding biozones.Facultad de Ciencias Naturales y Muse

The Neuquén composite section: magnetostratigraphy and biostratigraphy of the marine lower Jurassic from the Neuquén basin (Argentina)

Paleomagnetic and biostratigraphic data from five marine sedimentary sections in the Argentine Neuquén basin have allowed to construct the Lower Jurassic Neuquén Composite Section. This composite section comprises 14 reversed and 11 normal polarity Zones, in relation to 17 Andean ammonite Assemblage Zones, spanning the Hettangian^Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower Jurassic marine successions in the Southern Hemisphere. The Neuquén composite Section was correlated to the International Mesozoic Polarity Time Scale which, for the Lower Jurassic, comprises 54 polarity Zones and 16 Standard ammonite Zones. The correlation between the regional and the international biomagnetostratigraphic scales supports but also refines the correlation between the Andean and Standard ammonite zonations. Correlation between the Neuquén composite Section and the polarity sequences recorded in each section helped to assign several unfossiliferous stratigraphical levels to the corresponding biozones.Facultad de Ciencias Naturales y Muse

The Neuquén composite section: magnetostratigraphy and biostratigraphy of the marine lower Jurassic from the Neuquén basin (Argentina)

Paleomagnetic and biostratigraphic data from five marine sedimentary sections in the Argentine Neuquén basin have allowed to construct the Lower Jurassic Neuquén Composite Section. This composite section comprises 14 reversed and 11 normal polarity Zones, in relation to 17 Andean ammonite Assemblage Zones, spanning the Hettangian^Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower Jurassic marine successions in the Southern Hemisphere. The Neuquén composite Section was correlated to the International Mesozoic Polarity Time Scale which, for the Lower Jurassic, comprises 54 polarity Zones and 16 Standard ammonite Zones. The correlation between the regional and the international biomagnetostratigraphic scales supports but also refines the correlation between the Andean and Standard ammonite zonations. Correlation between the Neuquén composite Section and the polarity sequences recorded in each section helped to assign several unfossiliferous stratigraphical levels to the corresponding biozones.Facultad de Ciencias Naturales y Muse

Exploring New Lagrangian Cyclers to Enhance Science: Communications with CubeSat Technology

This paper discusses the opportunities that abound by using the CubeSat technology to travel to and communicate with the International Space Station, explore space, monitor space weather, monitor space debris and perhaps travel to Mars

Genomic characterization and gene regulation optimization to further improve an enzymatic mix used as feed additive

A common indigestible fraction of cereal grains, representing a large part of poultry diet, is their content in non-starch polysaccharides (NSP). Talaromyces versatilis is a filamentous fungus presenting the capability to secrete a mixture of enzymes used as animal feed additive (Rovabio® Excel) to enhance hydrolysis of plant cell wall polysaccharides. When incorporated to feed, the nutrients are more efficiently digested leading to a decreased need in agricultural products and hence a more sustainable production of poultry meat. In this context, the genome of T. versatilis was sequenced and annotated with a focus on genes likely to encode glycoside hydrolases, transcription factors and proteins involved in the secretion pathway. We also undertook a genome-wide transcriptome analysis, of the fungus exposed to glucose or milled wheat straw (a complex lignocellulosic material), using RNA-seq. The data revealed that, incubated on glucose and then transferred to wheat straw, the mycellium expressed differentially 926 genes between the two conditions. The differential response in gene expression of key mutants such as △xlnR, △creA or △araR were analysed in order to study their roles in regulating transcription. This approach provides a global view of the network that regulates the expression of the glycoside hydrolyse-encoding genes. More specifically, XlnR was identified as the transcription factor controling expression of genes involved in arabinoxylan degradation. Within the variety of NSP, arabinoxylan is the prominent type for wheat and corn (around 50%). Despite being mainly composed of xylose (X) and arabinose (A), the A:X ratio are different between corn and wheat, with a higher value for corn and a higher proportion of substituted xyloses compared to wheat. Arabinofuranosidase activity enhancement is key to attack arabinoxylans with a high A:X ratio which are recalcitrant to breakdown by single xylanase activity. Therefore, we aimed at improving the Rovabio® Excel in order to improve its capacity to degrade highly branched arabinoxylans, by enriching it in arabinofuranosidases and xylanases. To address such a goal while keeping its enzymatic diversity, we over-expressed the XlnR transcription factor. As a result, we obtained a modified strain of Talaromyces versatilis with on optimized genetic regulation to secrete a higher amount of arabinoxylan degrading enzymes. The resulting product, named Rovabio® Advance, tested in broilers allowed restoring nutrient availability, and so growth performance, even with a nutrient content diluted by 3% compared to a control diet

Immunohistochemical diagnosis of Caprine alphaherpesvirus 1 (CpHV-1) in Mexico

The aim of this study was to identify the presence of Caprine alphaherpesvirus 1 (CpHV-1) in goat organs with suggestive injuries caused by the virus. A descriptive and retrospective study was performed, selecting necropsy cases suggestive of CpHV-1infection during a period of five years. Forty eight suspected cases were obtained, to which the immunohistochemistry technique with a CpHV-1 monoclonal antibody, was applied. We observed positivity in 24 goatling cases under 15 days (50%) and in 4 cases of adult animals (8.3%). The presence of CpHV-1 in goats from the Mexican plateau is confirmed

A new structural modification of stannite

[EN]: The crystal structure of the phase a-SnCu2FeS4, has been examined by EDX and electron and X-ray difraction techniques. This compound crystallizes in the tetragonal space group P4 (No. 81) with a=c= 541.4 (4) pm, Z=1, and it is a derivative structure of the basic sphalerite structure. The refinement of the structure converged to the final agreement index R(F)=0.060.[ES]: La estructura cristalina de la fase a-SnCu2FeS4 ha sido analizada por técnicas de difracción de rayos-X, electrones y Energía Dispersiva de Rayos-X. Este compuesto cristaliza en el sistema tetragonal, grupo espacial P4 (No. 81) with a=c=541,4(4) pm, Z=1 y puede ser descrita como una estructura derivada de la esfalerita. El refinamiento final de la estructura convergió a R(F)=0,060.This work was supported by FONDECYT contract 1960372 and the Programa de Intercambio Científico CONICYT (Chile) and CSIC (Spain), grant 96022.Peer Reviewe

The insulin-PI3K/TOR pathway induces a HIF-dependent transcriptional response in Drosophila by promoting nuclear localization of HIF-α /Sima

The hypoxia-inducible factor (HIF) is a heterodimeric transcription factor composed of a constitutively expressed HIF-β subunit and an oxygen-regulated HIF-α subunit. We have previously defined a hypoxia-inducible transcriptional response in Drosophila melanogaster that is homologous to the mammalian HIF-dependent response. In Drosophila, the bHLH-PAS proteins Similar (Sima) and Tango (Tgo) are the functional homologues of the mammalian HIF-α and HIF-β subunits, respectively. HIF-α/Sima is regulated by oxygen at several different levels that include protein stability and subcellular localization. We show here for the first time that insulin can activate HIF-dependent transcription, both in Drosophila S2 cells and in living Drosophila embryos. Using a pharmacological approach as well as RNA interference, we determined that the effect of insulin on HIF-dependent transcriptional induction is mediated by PI3K-AKT and TOR pathways. We demonstrate that stimulation of the transcriptional response involves upregulation of Sima protein but not sima mRNA. Finally, we have analyzed in vivo the effect of the activation of the PI3K-AKT pathway on the subcellular localization of Sima protein. Overexpression of dAKT and dPDK1 in normoxic embryos provoked a major increase in Sima nuclear localization, mimicking the effect of a hypoxic treatment. A similar increase in Sima nuclear localization was observed in dPTEN homozygous mutant embryos, confirming that activation of the PI3K-AKT pathway promotes nuclear accumulation of Sima protein. We conclude that regulation of HIF-α/Sima by the PI3K-AKT-TOR pathway is a major conserved mode of regulation of the HIF-dependent transcriptional response in Drosophila.Fil:Dekanty, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Lavista-Llanos, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Irisarri, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Wappner, P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Burdigalian deposits of the Santa Cruz Formation in the Sierra Baguales, Austral (Magallanes) Basin: Age, depositional environment and vertebrate fossils

Indexación: Web of Science; Scielo.ABSTRACT. A succession of marine and continental strata on the southern flank of Cerro Cono in the Sierra Baguales, northeast of Torres del Paine, can be correlated with stratigraphic units exposed along the southern border of the Lago Argentino region in Santa Cruz Province, Argentina. These include the Estancia 25 de Mayo Formation and the basal part of the Santa Cruz Formation. The lithological correlation is also confirmed by detrital zircon ages (maximum age of 18.23±0.26 Ma) and a rich assemblage of terrestrial vertebrate fossils, biostratigraphically equivalent to a postColhuehuapian, pre-Santacrucian South American Land Mammal Age (SALMA) fauna, suggesting a range of 19 to 17.8 Ma. Similar ages have been obtained from the basal part of the Santa Cruz Formation at Estancia Quién Sabe in southwestern Argentina, supporting the assumption of a regional continuity between these deposits. A measured lithostratigraphic column is presented and the depositional environment is interpreted as a coastal plain with small, meandering rivers and ephemeral floodplain lakes. The sedimentation coincides with intensified uplift of the Patagonian Andes during the ‘Quechua Phase’ of Andean tectonism, which is reflected by a change in paleocurrent directions from northwest to east-northeast. Keywords: Burdigalian, Santa Cruz Formation, Santacrucian SALMA, ‘Notohippidian’ fauna, Meandering rivers.RESUMEN. Una sucesión de estratos marinos y continentales en el flanco meridional del cerro Cono, en la sierra Baguales, al noreste de Torres del Paine, se correlaciona con estratos al sur de la región de lago Argentino en la Provincia de Santa Cruz, República Argentina. Estas unidades incluyen la Formación Estancia 25 de Mayo y la parte basal de la Formación Santa Cruz. La correlación litológica es, además, confirmada por datación de circones detríticos (edad máxima de 18,23±0,26 Ma) y un variado ensamble de vertebrados fósiles terrestres de edad post-Colhuehuapense a pre-Santacrucense en la escala de Edades Mamífero Sudamericanas (EMAS), con un rango temporal de entre 19 a 17,8 Ma. Edades similares han sido reportadas para la parte basal de la Formación Santa Cruz, en estancia Quién Sabe, en el suroeste de Argentina, ratificando la continuidad regional entre estos depósitos. Se presenta una columna estratigráfica y se interpreta el ambiente de depositación como una llanura costera con pequeños ríos sinuosos y lagos efímeros. La edad de sedimentación coincide con el solevantamiento de los Andes Patagónicos durante la 'Fase Quechua', lo que se ve reflejado por un cambio en la dirección de las paleocorrientes desde el noroeste hacia el este-noreste.http://ref.scielo.org/csxwd