547 research outputs found

    Hartree-Fock-Bogoliubov Calculations in Coordinate Space: Neutron-Rich Sulfur, Zirconium, Cerium, and Samarium Isotopes

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    Using the Hartree-Fock-Bogoliubov (HFB) mean field theory in coordinate space, we investigate ground state properties of the sulfur isotopes from the line of stability up to the two-neutron dripline (3452S^{34-52}S). In particular, we calculate two-neutron separation energies, quadrupole moments, and rms-radii for protons and neutrons. Evidence for shape coexistence is found in the very neutron-rich sulfur isotopes. We compare our calculations with results from relativistic mean field theory and with available experimental data. We also study the properties of neutron-rich zirconium (102,104Zr^{102,104}Zr), cerium (152Ce^{152}Ce), and samarium (158,160Sm^{158,160}Sm) isotopes which exhibit very large prolate quadrupole deformations.Comment: 7 pages, 6 figures, 2 tables submitted to Phys. Rev.

    A class of quasi-sparse companion pencils

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    In this paper, we introduce a general class of quasi-sparse potential companion pencils for arbitrary square matrix polynomials over an arbitrary field, which extends the class introduced in [B. Eastman, I.-J. Kim, B. L. Shader, K.N. Vander Meulen, Companion matrix patterns. Linear Algebra Appl. 436 (2014) 255-272] for monic scalar polynomials. We provide a canonical form, up to permutation, for companion pencils in this class. We also relate these companion pencils with other relevant families of companion linearizations known so far. Finally, we determine the number of different sparse companion pencils in the class, up to permutation.This work has been partially supported by theMinisterio de Economía y Competitividad of Spain through grants MTM2015-68805-REDT and MTM2015-65798-P

    Detección de Sclerotinia sclerotiorum en cultivos de chía (Salvia hispanica) en Tucumán durante la campaña 2014

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    La superficie cultivada con chía (Salvia hispanica L.) en el norte del país fue de aproximadamente 170.000 ha durante la campaña 2014. El área se ha extendido más allá del territorio de la provincia de Tucumán, hacia zonas de Salta y Jujuy, además de Santiago del Estero, Chaco, Formosa y, en menor escala, Entre Ríos.Fil: Aguaysol, Natalia C.. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Robles Terán, Luis. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Gonzalez, Victoria. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Lobo Zavalía, Ramiro. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Ploper, Leonardo Daniel. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina; Argentin

    Perturbed CD8+ T cell TIGIT/CD226/PVR axis despite early initiation of antiretroviral treatment in HIV infected individuals.

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    HIV-specific CD8+ T cells demonstrate an exhausted phenotype associated with increased expression of inhibitory receptors, decreased functional capacity, and a skewed transcriptional profile, which are only partially restored by antiretroviral treatment (ART). Expression levels of the inhibitory receptor, T cell immunoglobulin and ITIM domain (TIGIT), the co-stimulatory receptor CD226 and their ligand PVR are altered in viral infections and cancer. However, the extent to which the TIGIT/CD226/PVR-axis is affected by HIV-infection has not been characterized. Here, we report that TIGIT expression increased over time despite early initiation of ART. HIV-specific CD8+ T cells were almost exclusively TIGIT+, had an inverse expression of the transcription factors T-bet and Eomes and co-expressed PD-1, CD160 and 2B4. HIV-specific TIGIThi cells were negatively correlated with polyfunctionality and displayed a diminished expression of CD226. Furthermore, expression of PVR was increased on CD4+ T cells, especially T follicular helper (Tfh) cells, in HIV-infected lymph nodes. These results depict a skewing of the TIGIT/CD226 axis from CD226 co-stimulation towards TIGIT-mediated inhibition of CD8+ T cells, despite early ART. These findings highlight the importance of the TIGIT/CD226/PVR axis as an immune checkpoint barrier that could hinder future "cure" strategies requiring potent HIV-specific CD8+ T cells

    Estrutura populacional, tamanho e razão sexual de Podocnemis unifilis (Testudines, Podocnemididae) no rio Guaporé (RO), norte do Brasil

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    Population structure and sex ratio of Podocnemis unifilis was studied from June to November 1989 and from March to June 1990 in the Guaporé river and its tributaries São Domingos and São Miguel, in the municipality of Costa Marques, Rondônia, Brazil. The margins of these rivers are not altered much by human activities and the water is not polluted in any way. Turtles were captured using 12 fyke nets. Around 1 % of the captured turtles died using this method. The majority of the turtles was captured in the bays and oxbows (55.8%) and when the water level of the river was declining (N=785). The proportion of adults (73.4 %) in the sample was about three times higher than that of juveniles (26.6 %). The distribution of carapace length in males formed a normal curve, while that of females showed no well-defined pattern. The sex ratio of adults in this population was 9.8 males per female

    Human Immunodeficiency Virus type 1 in seronegative infants born to HIV-1-infected mothers

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    BACKGROUND: Some individuals repeatedly exposed to Human Immunodeficiency Virus do not seroconvert and are resistant to HIV infection. Here, in a pediatric cohort of HIV seronegative infants born of HIV-infected mothers, we have studied eight non-breastfed children in whom viral DNA was detected in their PBMC. Our objective was to assess whether silent infection in these children can be explained by the presence of integrated viral DNA. METHODS: The presence of viral DNA was corroborated by nested PCR with primers for gag and the nef/LTR regions of HIV-1. Integration of HIV DNA into the host genome was assessed by an Alu-LTR PCR. Amplicons were sequenced and phylogenetic analyzes were done. RESULTS: HIV-1 DNA was detected in the earliest available PBMC sample from all eight infants, and two of them tested positive for HIV DNA at 2 years of age. Nested PCR resulted in the amplification of gag, nef/LTR and Alu-LTR fragments, which demostrated that HIV-1 DNA was integrated in the host cell genome. Each individual has a characteristic sequence pattern and is different from the LTR sequence of HXB2 prototype virus and other Mexican isolates. CONCLUSION: HIV-1 DNA was observed in PBMC from HIV exposed seronegative children in this pediatric cohort

    In Situ Characterization of Human Lymphoid Tissue Immune Cells by Multispectral Confocal Imaging and Quantitative Image Analysis; Implications for HIV Reservoir Characterization.

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    CD4 T cells are key mediators of adaptive immune responses during infection and vaccination. Within secondary lymphoid organs, helper CD4 T cells, particularly those residing in germinal centers known as follicular helper T cells (Tfh), provide critical help to B-cells to promote their survival, isotype switching and selection of high affinity memory B-cells. On the other hand, the important role of Tfh cells for the maintenance of HIV reservoir is well documented. Thus, interrogating and better understanding the tissue specific micro-environment and immune subsets that contribute to optimal Tfh cell differentiation and function is important for designing successful prevention and cure strategies. Here, we describe the development and optimization of eight multispectral confocal microscopy immunofluorescence panels designed for in depth characterization and immune-profiling of relevant immune cells in formalin-fixed paraffin-embedded human lymphoid tissue samples. We provide a comprehensive library of antibodies to use for the characterization of CD4+ T-cells -including Tfh and regulatory T-cells- as well as CD8 T-cells, B-cells, macrophages and dendritic cells and discuss how the resulting multispectral confocal datasets can be quantitatively dissected using the HistoCytometry pipeline to collect information about relative frequencies and immune cell spatial distributions. Cells harboring actively transcribed virus are analyzed using an in-situ hybridization assay for the characterization of HIV mRNA positive cells in combination with additional protein markers (multispectral RNAscope). The application of this methodology to lymphoid tissues offers a means to interrogate multiple relevant immune cell targets simultaneously at increased resolution in a reproducible manner to guide CD4 T-cell studies in infection and vaccination

    Substrate-induced magnetic anisotropy in La0.7Sr 0.3MnO3 epitaxial thin films grown onto (110) and (118) SrTiO3 substrates

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    We show a detailed magneto-optical Kerr study at room temperature of well characterized epitaxial La0.7Sr0.3MnO3 (LSMO) thin films grown onto (110) and (118) SrTiO3 substrates. The films present a well-defined uniaxial (two-fold) magnetic anisotropy ascribed to substrate-induced anisotropy. In particular, the in-plane uniaxial anisotropy in the(110)-oriented LSMO films originates from the existence of elongated in-plane [001]-oriented structures. Similar elongated structures, parallel to the [110] crystallographic direction, are found for LSMO films grown on (118) STO surfaces. In all films, such a uniaxial magnetic anisotropy is characterized by an easy axis lying along the elongated structures. Furthermore, the vectorial-resolved hysteresis loops as a function of the in-plane applied field direction are interpreted in terms of rotation and propagation and nucleation of magnetic domains processes. Our results demonstrate the tailoring of magnetic anisotropy by exploiting the substrate-induced anisotropy in epitaxial thin filmsThis work was supported in part by the Spanish MICINN through Project No. CSD2007-00010 and by the Comunidad de Madrid through Project No. S2009/MAT-1726. P.P. thanks the European Science Foundation (ESF) through the activity entitled ’Thin Films for Novel Oxide Devices’ (http://www.ims.tnw.utwente.nl/thiox/) for partial financial support through exchange grant

    Population structure, sex ratio and abundance of Podocnemis sextuberculata (Testudines, Podocnemididae) in the Reserva de Desenvolvimento Sustentável Mamirauá, Amazonas, Brazil

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    Population structure, sex ratio and abundance of Podocnemis sextuberculata (Testudines, Podocnemididae) in the Reserva de Desenvolvimento Sustentável Mamirauá, Amazonas, Brazil. We studied turtles in the focal area of the Reserva de Desenvolvimento Sustentável Mamirauá from September 1996 through August 1998. The reserve is located in the western part of the Brazilian Amazon, between the Japurá, Solimões, and Auti-Paraná rivers, near the city of Tefé, in the state of Amazonas. In this study the populacion structure, sex ratio and abundance of Podocnemis sextuberculata were investigated. We intensively studied the population of turtles in the Jarauá river basin in order to determine population structure. We sampled turtles in different sectors of the focal area of the reserve for one month each year during July and August 1997 and 1998. We captured the turtles using flag gill nets and trammel nets. The type of net and size of the nets used influenced the size of the turtles captured. The nets used by the local fishermen were sexually selective in the capture of turtles. Seventy two per cent of the P. sextuberculata captured were adults; 13 % juveniles and 14.7 % subadults. During the second year of the study we found a lower density of turtles in the five areas which we sampled both years. The sex ratio of captured P. sextuberculata was 1.87 males per female

    On the stability of a variety of organic photovoltaic devices by IPCE and in situ IPCE analyses - the ISOS-3 inter-laboratory collaboration

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    This work is part of the inter-laboratory collaboration to study the stability of seven distinct sets of state-of-the-art organic photovoltaic (OPV) devices prepared by leading research laboratories. All devices have been shipped to and degraded at RISO-DTU up to 1830 hours in accordance with established ISOS-3 protocols under defined illumination conditions. In this work, we apply the Incident Photon-to-Electron Conversion Efficiency (IPCE) and the in situ IPCE techniques to determine the relation between solar cell performance and solar cell stability. Different ageing conditions were considered: accelerated full sun simulation, low level indoor fluorescent lighting and dark storage. The devices were also monitored under conditions of ambient and inert (N 2) atmospheres, which allows for the identification of the solar cell materials more susceptible to degradation by ambient air (oxygen and moisture). The different OPVs configurations permitted the study of the intrinsic stability of the devices depending on: two different ITO-replacement alternatives, two different hole extraction layers (PEDOT:PSS and MoO 3), and two different P3HT-based polymers. The response of un-encapsulated devices to ambient atmosphere offered insight into the importance of moisture in solar cell performance. Our results demonstrate that the IPCE and the in situ IPCE techniques are valuable analytical methods to understand device degradation and solar cell lifetime. © 2012 the Owner Societies.This work has been supported by the Danish Strategic Research Council (2104-07-0022), EUDP (j.no. 64009-0050), and the Danish National Research Foundation. Partial financial support was also received from the European Commission as part of the Framework 7 ICT 2009 collaborative project HIFLEX (grant no. 248678), partial financial support from the EUIndian framework of the ‘‘Largecells’’ project that received funding from the European Commission’s Seventh Framework Programme (FP7/2007–2013. grant no. 261936), partial financial support was also received from the European Commission as part of the Framework 7 ICT 2009 collaborative project ROTROT (grant no. 288565) and from PVERA-NET (project acronym POLYSTAR). To CONACYT (México) for the Ph.D. scholarship awarded to G. T.-E, to the Spanish Ministry of Science and Innovation, MICINN-FEDER project ENE2008-04373, to the Consolider NANOSELECT project CSD2007-00041, to the Xarxa de Referència en Materials Avançats per a l’Energia, XaRMAE of the Catalonia Government (Spain). RR and HH are grateful for financial support from the Thuringian Ministry of Culture and the German Federal Ministry of Education and Research in the frameworks of FIPV II and PPP (contract number 13N9843), respectively. DMT acknowledges generous support from the Inger and Jens Bruun Foundation through The American–Scandinavian Foundation.Peer Reviewe
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