Implementation of a network of nuclear reactions of moderate size aimed at simulating Type Ia supernova explosions

A key ingredient in any numerical study of supernova explosions is the nuclear network routine that is coupled with the hydrodynamic simulation code. When these studies are performed in more than one dimension, the size of the network is severely limited by computational issues. Nevertheless, the characteristic size of these networks has been increasing over the years, from around seven nuclei in pioneering multi-D calculations to roughly fifty at present times. The main goal of this work is to improve, optimize and test a nuclear network of 87 nuclei specially addressed to multidimensional studies of both types of supernova explosions, but with emphasis in thermonuclear Type Ia events. The nuclear network, Net87, is a natural extension of the old network with 14 species, Net14, which was routinely used by the UPC-SciCore collaboration to simulate supernova explosions with good results. Net87 includes reactions for neutrons, protons and alpha particles. One relevant, and original, feature is that electron captures on protons have been incorporated into the network, providing a better track of both, the neutronized species and the gas pressure. A second important feature is that the reactions are implicitly coupled with the temperature, which allows for a more stable approach to the nuclear statistical equilibrium regime and to the freeze-out of the reactions during the expansion. Here we analyze the performance of the Net87 routine in light of both: the computational overhead of the algorithm and the released nuclear energy and produced yields during the combustion in typical Type Ia Supernova (SN Ia) conditions

Approaching the exascale simulation of subsonic turbulence with smoothed particle hydrodynamics

The candidate will work in collaboration with the SPH-EXA and SKAO-Switzerland projects.Turbulence is key to many astrophysical and cosmological scenarios. Hence, a correct depiction of it in numerical simulations is of capital importance. Kolmogorov's theory states that in the subsonic regime the energy associated with the scale of the turbulent structures follows the power law � ∝ � −5∕3 , where � is the wave-number. Smoothed Particle Hydrodynamics simulations have traditionally shown difficulties building up a Kolmogorov-like turbulent cascade. The main reason for this can be traced back to the errors in gradient evaluation when standard SPH methods are used, jointly with over-viscous behavior from traditional artificial viscosity formulations. These problems can be tackled nowa- days with modern implementations of the gradient evaluation that are much more accurate, and also using adaptive switches and artificial viscosity cleaners that reduce dissipation where and when needed. With the goal of testing this new implementation, as well as the performance of the new state- of-the-art SPH-EXA code, a set of turbulence simulations have been carried out, that represent the most accurate and highest resolution SPH-based turbulence simulations to date. The combination of the high scalability of SPH-EXA with the use of upgraded hydrodynamics has shown a sizeable improvement in the results of the subsonic turbulence simulation

Modelling and designing a Paul ion trap

A Paul trap or quadrupole ion trap is a device designed to confine ions or charged particles in a given space. It consists of four electrodes that produce electric fields varying in time. The voltage applied to these electrodes varies harmonically with low frequency (quasi-static regime), which simplifies the model. The goal of this project is to numerically simulate in matlab a Paul trap and the motion of the ions trapped in it by discretizing the Poisson equation and applying the method of moments (MoM), first in 2D and then generalized to 3D2019/202

A moderately-sized nuclear network to assist multi-D hydrodynamic simulations of supernova explosions

A key ingredient in any numerical study of supernova explosions is the nuclear network routine that is coupled with the hydrodynamic simulation code. When these studies are performed in more than one dimension, the size of the network is severely limited by computational issues. In this work, we propose a nuclear network (net87) which is close to one hundred nuclei and could be appropriate to simulate supernova explosions in multidimensional studies. One relevant feature is that electron and positron captures on free protons and neutrons have been incorporated to the network. Such addition allows for a better track of both, the neutronized species and the gas pressure. A second important feature is that the reactions are implicitly coupled with the temperature, which enhances the stability in the nuclear statistical equilibrium (NSE) regime. Here we analyze the performance of net87 in light of both: the computational overhead of the algorithm and the outcome in terms of the released nuclear energy and produced yields in typical Type Ia Supernova conditions.Postprint (published version

The program of national liberation in the 70s Argentina: from Montoneros to the Confederación General Económica (CGE)

En este artículo realizamos un estudio del programa político de dos importantes actores del proceso político de la década del ’70 en Argentina: la organización político-militar Montoneros y la corporación empresaria Confederación General Económica (CGE). Mediante el análisis comparado de los documentos fundamentales de ambos, buscamos detectar aspectos comunes y elementos distintivos entre uno y otro. Concluimos que desarrollan variantes de un mismo programa que se plantea el fin del dominio imperialista y la defensa de los intereses nacionales, mediante el estímulo a la empresa nacional y la redistribución del ingreso: el programa de liberación nacional.In this article we conducted a study of the political program of two major players in the political process in the 70s in Argentina: the military-political organization Montoneros and the interest group Confederación General Económica (CGE). Through a comparative analysis of the fundamental documents of both organizations, we seek to detect coincidences and distinctive elements of each other. We conclude that they develop variants of the same program which propose the end of imperialist domination and defense of national interests, by encouraging national company and income redistribution: the program of national liberation.Fil: Sanz Cerbino, Gonzalo Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios Urbanos y Regionales; ArgentinaFil: Lissandrello, Guido Axel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios Urbanos y Regionales; Argentin

Setup and validation of shake-flask procedures for the determinationof partition coefficients (log D) from low drug amounts

Several procedures based on the shake-flask method and designed to require a minimum amount of drug for octanol-water partition coefficient determination have been established and developed. The procedures have been validated by a 28 substance set with a lipophilicity range from -2.0 to 4.5 (logD7.4). The experimental partition is carried out using aqueous phases buffered with phosphate (pH 7.4) and n-octanol saturated with buffered water and the analysis is performed by liquid chromatography. In order to have accurate results, four procedures and eight different ratios between phase volumes are proposed. Each procedure has been designed and optimized (for partition ratios) for a specific range of drug lipophilicity (low, regular and high lipophilicity) and solubility (high and low aqueous solubility). The procedures have been developed to minimize the measurement in the octanolic phase. Experimental logD7.4 values obtained from different procedures and partition ratios show a standard deviation lower than 0.3 and there is a nice agreement when these values are compared with the reference literature one

Donor NK and T Cells in the Periphery of Lung Transplant Recipients Contain High Frequencies of Killer Cell Immunoglobulin-Like Receptor-Positive Subsets

Introduction For end-stage lung diseases, double lung transplantation (DLTx) is the ultimate curative treatment option. However, acute and chronic rejection and chronic dysfunction are major limitations in thoracic transplantation medicine. Thus, a better understanding of the contribution of immune responses early after DLTx is urgently needed. Passenger cells, derived from donor lungs and migrating into the recipient periphery, are comprised primarily by NK and T cells. Here, we aimed at characterizing the expression of killer cell immunoglobulin-like receptors (KIR) on donor and recipient NK and T cells in recipient blood after DLTx. Furthermore, we investigated the functional status and capacity of donor vs . recipient NK cells. Methods Peripheral blood samples of 51 DLTx recipients were analyzed pre Tx and at T0, T24 and 3wk post Tx for the presence of HLA-mismatched donor NK and T cells, their KIR repertoire as well as activation status using flow cytometry. Results Within the first 3 weeks after DLTx, donor NK and T cells were detected in all patients with a peak at T0. An increase of the KIR2DL/S1-positive subset was found within the donor NK cell repertoire. Moreover, donor NK cells showed significantly higher frequencies of KIR2DL/S1-positive cells (p<0.01) 3wk post DLTx compared to recipient NK cells. This effect was also observed in donor KIR + T cells 3wk after DLTx with higher proportions of KIR2DL/S1 (p<0.05) and KIR3DL/S1 (p<0.01) positive T cells. Higher activation levels of donor NK and T cells (p<0.001) were detected compared to recipient cells via CD25 expression as well as a higher degranulation capacity upon activation by K562 target cells. Conclusion Higher frequencies of donor NK and T cells expressing KIR compared to recipient NK and T cells argue for their origin in the lung as a part of a highly specialized immunocompetent compartment. Despite KIR expression, higher activation levels of donor NK and T cells in the periphery of recipients suggest their pre-activation during the ex situ phase. Taken together, donor NK and T cells are likely to have a regulatory effect in the balance between tolerance and rejection and, hence, graft survival after DLTx

Molecular landscape and prognostic impact of FLT3 -ITD insertion site in acute myeloid leukemia : RATIFY study results

In acute myeloid leukemia (AML) internal tandem duplications of the FLT3 gene (FLT3- ITD) are associated with poor prognosis. Retrospectively, we investigated the prognostic and predictive impact of FLT3 -ITD insertion site (IS) in 452 patients randomized within the RATIFY trial, which evaluated midostaurin additionally to intensive chemotherapy. Next-generation sequencing identified 908 ITDs, with 643 IS in the juxtamembrane domain (JMD) and 265 IS in the tyrosine kinase domain-1 (TKD1). According to IS, patients were categorized as JMDsole (n = 251, 55%), JMD and TKD1 (JMD/TKD1; n = 117, 26%), and TKD1sole (n = 84, 19%). While clinical variables did not differ among the 3 groups, NPM1 mutation was correlated with JMDsole (P = 0.028). Overall survival (OS) differed significantly, with estimated 4-year OS probabilities of 0.44, 0.50, and 0.30 for JMDsole, JMD/TKD1, and TKD1sole, respectively (P = 0.032). Multivariate (cause-specific) Cox models for OS and cumulative incidence of relapse using allogeneic hematopoietic cell transplantation (HCT) in first complete remission as a time-dependent variable identified TKD1sole as unfavorable and HCT as favorable factors. In addition, Midostaurin exerted a significant benefit only for JMDsole. Our results confirm the distinct molecular heterogeneity of FLT3 -ITD and the negative prognostic impact of TKD1 IS in AML that was not overcome by midostaurin

The genetic ancestry of American Creole cattle inferred from uniparental and autosomal genetic markers

Cattle imported from the Iberian Peninsula spread throughout America in the early years of discovery and colonization to originate Creole breeds, which adapted to a wide diversity of environments and later received influences from other origins, including zebu cattle in more recent years. We analyzed uniparental genetic markers and autosomal microsatellites in DNA samples from 114 cattle breeds distributed worldwide, including 40 Creole breeds representing the whole American continent, and samples from the Iberian Peninsula, British islands, Continental Europe, Africa and American zebu. We show that Creole breeds differ considerably from each other, and most have their own identity or group with others from neighboring regions. Results with mtDNA indicate that T1c-lineages are rare in Iberia but common in Africa and are well represented in Creoles from Brazil and Colombia, lending support to a direct African influence on Creoles. This is reinforced by the sharing of a unique Y-haplotype between cattle from Mozambique and Creoles from Argentina. Autosomal microsatellites indicate that Creoles occupy an intermediate position between African and European breeds, and some Creoles show a clear Iberian signature. Our results confirm the mixed ancestry of American Creole cattle and the role that African cattle have played in their development

Is hybridization a source of adaptive venom variation in rattlesnakes? A test, using a crotalus scutulatus × viridis hybrid zone in Southwestern New Mexico

Venomous snakes often display extensive variation in venom composition both between and within species. However, the mechanisms underlying the distribution of different toxins and venom types among populations and taxa remain insufficiently known. Rattlesnakes (Crotalus, Sistrurus) display extreme inter- and intraspecific variation in venom composition, centered particularly on the presence or absence of presynaptically neurotoxic phospholipases A2 such as Mojave toxin (MTX). Interspecific hybridization has been invoked as a mechanism to explain the distribution of these toxins across rattlesnakes, with the implicit assumption that they are adaptively advantageous. Here, we test the potential of adaptive hybridization as a mechanism for venom evolution by assessing the distribution of genes encoding the acidic and basic subunits of Mojave toxin across a hybrid zone between MTX-positive Crotalus scutulatus and MTX-negative C. viridis in southwestern New Mexico, USA. Analyses of morphology, mitochondrial and single copy-nuclear genes document extensive admixture within a narrow hybrid zone. The genes encoding the two MTX subunits are strictly linked, and found in most hybrids and backcrossed individuals, but not in C. viridis away from the hybrid zone. Presence of the genes is invariably associated with presence of the corresponding toxin in the venom. We conclude that introgression of highly lethal neurotoxins through hybridization is not necessarily favored by natural selection in rattlesnakes, and that even extensive hybridization may not lead to introgression of these genes into another species