552 research outputs found

    Bound states of Θ+\Theta^+ in nuclei

    Full text link
    We study the binding energy and the width of the Θ+\Theta^+ in nuclei, associated to the KNK N and KπN K \pi N components. The first one leads to negligible contributions while the second one leads to a sizeable attraction, enough to bind the Θ+\Theta^+ in nuclei. Pauli blocking and binding effects on the KNK N decay reduce considerably the Θ+\Theta^+ decay width in nuclei and medium effects associated to the KπN K \pi N component also lead to a very small width, as a consequence of which one finds separation between the bound levels considerably larger than the width of the states.Comment: Presentation in the 10th International Baryon Conference BARYON0

    Waterborne Exophiala species causing disease in cold-blooded animals

    Get PDF
    The majority of mesophilic waterborne species of the black yeast genus Exophiala (Chaetothyriales) belong to a single clade judging from SSU rDNA data. Most taxa are also found to cause cutaneous or disseminated infections in cold-blooded, water animals, occasionally reaching epidemic proportions. Hosts are mainly fish, frogs, toads, turtles or crabs, all sharing smooth, moist or mucous skins and waterborne or amphibian lifestyles; occasionally superficial infections in humans are noted. Cold-blooded animals with strictly terrestrial life styles, such as reptiles and birds are missing. It is concluded that animals with moist skins, i.e. those being waterborne and those possessing sweat glands, are more susceptible to black yeast infection. Melanin and the ability to assimilate alkylbenzenes are purported general virulence factors. Thermotolerance influences the choice of host. Exophiala species in ocean water mostly have maximum growth temperatures below 30 °C, whereas those able to grow until 33(−36) °C are found in shallow waters and occasionally on humans. Tissue responses vary with the phylogenetic position of the host, the lower animals showing poor granulome formation. Species circumscriptions have been determined by multilocus analyses involving partial ITS, TEF1, BT2 and ACT1

    From plants to nematodes: Serratia grimesii BXF1 genome reveals an adaptation to the modulation of multi-species interactions

    Get PDF
    Serratia grimesii BXF1 is a bacterium with the ability to modulate the development of several eukaryotic hosts. Strain BXF1 was isolated from the pinewood nematode, Bursaphelenchus xylophilus, the causative agent of pine wilt disease affecting pine forests worldwide. This bacterium potentiates Bursaphelenchus xylophilus reproduction, acts as a beneficial pine endophyte, and possesses fungal and bacterial antagonistic activities, further indicating a complex role in a wide range of trophic relationships. In this work, we describe and analyse the genome sequence of strain BXF1, and discuss several important aspects of its ecological role. Genome analysis indicates the presence of several genes related to the observed production of antagonistic traits, plant growth regulation and the modulation of nematode development. Moreover, most of the BXF1 genes are involved in environmental and genetic information processing, which is consistent with its ability to sense and colonize several niches. The results obtained in this study provide the basis to a better understanding of the role and evolution of strain BXF1 as a mediator of interactions between organisms involved in a complex disease system. These results may also bring new insights into general Serratia and Enterobacteriaceae evolution towards multitrophic interactions

    Baryonic Resonances from Baryon Decuplet-Meson Octet Interactions and the Exotic Resonance S=1, I=1, J^P=3/2-

    Get PDF
    Using the lowest order chiral Lagrangian we study s-wave interactions of the baryon decuplet with the octet of pseudoscalar mesons. We find two bound states in the flavour SU(3) limit corresponding to the octet and decuplet representations. These are found to split into eight different trajectories in the complex plane when the SU(3) symmetry is broken gradually. Finally, we are able to provide a reasonable description for a good number of 4-star 3/2- resonances listed by the Particle Data Group. In particular, the Xi(1820), the Lambda(1520) and the Sigma(1670) states are well reproduced. We predict a few other resonances and also evaluate the couplings of the observed resonances to the various channels from the residues at the poles of the scattering matrix from where partial decay widths into different channels can be evaluated.Comment: Talk given at 10th International Conference on the Structure of Baryons (Baryon 2004) at Palaiseau (France), 25-29 October 200

    Inclusive Nucleon Emission Induced by Quasi--Elastic Neutrino--Nucleus Interactions

    Get PDF
    We study the quasi--elastic contribution to the inclusive (Îœl,ÎœlN)(\nu_l,\nu_l N), (Îœl,l−N)(\nu_l,l^- N), (Μˉl,ΜˉlN)({\bar \nu}_l,{\bar \nu}_l N) and (Μˉl,l+N)({\bar \nu}_l,l^+ N) reactions in nuclei using a Monte Carlo simulation method to account for the rescattering of the outgoing nucleon. As input, we take the reaction probability from the microscopical many body framework developed in Phys. Rev. {\bf C70} (2004) 055503 for charged-current induced reactions, while for neutral currents we use results from a natural extension of the model described in that reference. The nucleon emission process studied here is a clear signal for neutral--current neutrino driven reactions, that can be used in the analysis of future neutrino experiments.Comment: 23 pages, 17 figures; Version 2: few typos correcte

    Un nuevo método de sintesis del carbonato de manganeso como electrodo negativo en baterías de ión-litio

    Get PDF
    III Encuentro sobre Nanociencia y NanotecnologĂ­a de Investigadores y TecnĂłlogos Andaluce

    Two-meson cloud contribution to the baryon antidecuplet self-energy

    Get PDF
    We study the self-energy of the SU(3) antidecuplet coming from two-meson virtual clouds. Assuming that the exotic Theta+ belongs to an antidecuplet representation with N(1710) as nucleon partner, we derive effective Lagrangians that describe the decay of N(1710) into N pi pi with two pions in s- or p-wave. It is found that the self-energies for all members of the antidecuplet are attractive, and the larger strangeness particle is more bound. From two-meson cloud, we obtain about 20 % of the empirical mass splitting between states with different strangeness.Comment: 4 pages, 2 figures, 1 table, Talk given at the 10th International Conference on Baryons (Baryons04), Palaiseau (France), October 25-29, 200

    Laser Surface Modification in Ti-xNb-yMo Alloys Prepared by Powder Metallurgy

    Get PDF
    [Abstract] The main objective was to study the effect of surface modification by laser on Ti-Nb-Mo powder metallurgical alloys to improve their mechano-chemical behavior and their application as a biomedical implant. The used powder mixtures were produced in an inert atmosphere. Uniaxial compaction took place at 600 MPa with high-vacuum sintering at 1250 °C for 3 h. The specimens for the three-point flexure test were prepared and their mechanical properties determined. Microstructural characterization was performed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) to obtain the distribution of phases, porosity, size, and shape of the grains of each alloy. Corrosion behavior was evaluated by electrochemical tests using an artificial saliva electrolyte modified from Fusayama at 37 °C. Chemical characterization was completed by analyzing the ionic release by Inductively coupled plasma atomic emission spectroscopy (ICP-EOS) after immersion for 730 h in Fusayama solution modified with NaF at 37 °C to simulate a 20-year life span based on a daily 2-min cycle of three toothbrushes. Corrosion behavior confirmed promising possibilities for the biomedicine field. The surface porosity of the samples not submitted to surface treatment deteriorated properties against corrosion and ion release. The obtained phase was ÎČ, with a low α”-martensite percentage. The maximum resistance to bending was greater after surface fusion. Plastic deformations were above 7% under some conditions. Microhardness came close to 300 HV in heat-affected zone (HAZ) and 350 HV in fusion zone (FZ) (under the determined condition. The elastic modulus lowered by around 10%. The corrosion rate was lower in Ti-27Nb-8Mo and Ti-35Nb-6Mo. Niobium release was significant, but below the physiological limit.The authors thank the Ministerio de EconomĂ­a y Competitividad de España for Research Project RTI2018-097810-B-I00 and the Ministerio de EconomĂ­a y Competitividad de España for Research Project RTI2018-096472-B-I00. The European Commission thanks to FEDER and the SĂŁo Paulo State Research Support Foundation (FAPESP) [Grant: 2019/24237-6].Fundação de Amparo Ă  Pesquisa do Estado de SĂŁo Paulo; 2019/24237-

    A charter for sustainable tourism after COVID-19

    Get PDF
    The SARS-CoV-2 virus that causes the COVID-19 disease is highly infectious and contagious. The long-term consequences for individuals are as yet unknown, while the long-term effects on the international community will be dramatic. COVID-19 has changed the world forever in every imaginable respect and has impacted heavily on the international travel, tourism demand, and hospitality industry, which is one of the world's largest employers and is highly sensitive to significant shocks like the COVID-19 pandemic. It is essential to investigate how the industry will recover after COVID-19 and how the industry can be made sustainable in a dramatically changed world. This paper presents a charter for tourism, travel, and hospitality after COVID-19 as a contribution to the industry
    • 

    corecore