Neutralizing antibodies in cats infected with feline immunodeficiency virus.

Sera from cats experimentally infected with five isolates of feline immunodeficiency virus (FIV) from various geographical regions and from FIV enzyme-linked immunosorbent assay-seropositive field cats from four European countries neutralized the Petaluma strain of FIV (FIV-P), originally isolated in California, at high titers. In addition, FIV-P and a European isolate proved equally susceptible to neutralization by all sera tested. Coupled with observations by Fevereiro et al. (M. Fevereiro, C. Roneker, A. Laufs, L. Tavares, and F. de Noronha, J. Gen. Virol. 72:617-622, 1991), these findings indicate that most if not all FIV strains circulating in Europe and the United States share important neutralization-inducing epitopes

From present pasts: towards an ethnography of archives

Fil: Crespo, Carolina F. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina.Fil: Crespo, Carolina F. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tozzini, María A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Tozzini, María A. Investigaciones Socio-Históricas Regionales. Centro de Estudios de Historia Regional - Nodo Cehir - Ishir; ArgentinaFil: Tozzini, María A. Universidad Nacional de Río Negro; ArgentinaThis article seeks to provide a theoretical and methodological approach on how to use different types of sources from different historical periods in researches focused on examining the processes of reconstruction of memory and the past, especially but not exclusively, in the context of conflicts and territorial claims by subordinate sectors. We refer to the importance of analyzing in a crossed and a situational way, how different types of files, that are of a past still present, are critically and creatively redefined and re read in ethnographic contexts. This proposal involves organizing knowledge practices, introduce the discussion of historical archives and pointing out the potential that brings observation, reinscription and analysis under an approach and an ethnographic context.Este trabajo procura aportar una propuesta teórico/metodológica sobre cómo abordar registros de diferentes períodos históricos en investigaciones centradas en los procesos de reconstrucción de la memoria y el pasado, en especial, aunque no exclusivamente, en el marco de conflictos y demandas territoriales por parte de sectores subalternos. Nos referimos a la relevancia de analizar, cruzada y situadamente, cómo son redefinidos y releídos, crítica y creativamente en contextos etnográficos, diversos tipos de archivos que se constituyen en registros sobre un pasado aún presente. La propuesta supone organizar las prácticas de conocimiento, introducir la discusión sobre los archivos históricos y señalar las potencialidades que aporta su observación, reinscripción y análisis bajo un enfoque y contexto etnográfic

Increasing the active surface of titanium islands on graphene by nitrogen sputtering

Titanium-island formation on graphene as a function of defect density is investigated. When depositing titanium on pristine graphene, titanium atoms cluster and form islands with an average diameter of about 10nm and an average height of a few atomic layers. We show that if defects are introduced in the graphene by ion bombardment, the mobility of the deposited titanium atoms is reduced and the average diameter of the islands decreases to 5nm with monoatomic height. This results in an optimized coverage for hydrogen storage applications since the actual titanium surface available per unit graphene area is significantly increased

Carbon budget of an agroforestry system after being converted from a poplar short rotation coppice

Poplar (Populus L. spp.) Short Rotation Coppice systems (SRCs) for bioenergy production are being converted back to arable land. Transitioning to Alley Cropping Systems (ACSs) could be a suitable strategy for integrating former tree rows and arable crops. A field trial (Pisa, Central Italy) was set up with the aim of assessing the C storage of an ACS system based on hybrid poplar and sorghum (Sorghum bicolor L. Moench) and comparing it with that of an SRC cultivation system. The carbon budget at the agroecosystem scale was assessed in the first year of the transition using the net biome production (NBP) approach with a simplified method. The overall NBP for the SRC was positive (96 ± 40 g C m−2 year−1), highlighting that the system was a net carbon sink (i.e., NBP > 0). However, the ACS registered a net C loss (i.e., NBP < 0), since the NBP was −93 ± 56 g C m−2 year−1. In the first year of the transition, converting the SRC into an ACS counteracted the potential beneficial effect of C storage in tree belowground biomass due to the high heterotrophic respiration rate recorded in the ACS, which was fostered by the incorporation of residues and tillage disturbance in the alley. Additional years of heterotrophic respiration measurements could allow for an estimate of the speed and extent of C losses

Spontaneous formation and stability of small GaP fullerenes

We report the spontaneous formation of a GaP fullerene cage in ab-initio Molecular Dynamics simulations starting from a bulk fragment. A systematic study of the geometric and electronic properties of neutral and ionized GaP clusters suggests the stability of hetero-fullerenes formed by a compound with zincblend bulk structure. We find that GaP fullerenes up to 28 atoms have high symmetry, closed electronic shells, large HOMO-LUMO energy gaps and do not dissociate when ionized. We compare our results for GaP with those obtained by other groups for the corresponding BN clusters.Comment: To appear on PRL, 4 pages, 1 figure, Late

A Condensation-Ordering Mechanism in Nanoparticle-Catalyzed Peptide Aggregation

Nanoparticles introduced in living cells are capable of strongly promoting the aggregation of peptides and proteins. We use here molecular dynamics simulations to characterise in detail the process by which nanoparticle surfaces catalyse the self- assembly of peptides into fibrillar structures. The simulation of a system of hundreds of peptides over the millisecond timescale enables us to show that the mechanism of aggregation involves a first phase in which small structurally disordered oligomers assemble onto the nanoparticle and a second phase in which they evolve into highly ordered beta-sheets as their size increases

Mechanical Strength of 17 134 Model Proteins and Cysteine Slipknots

A new theoretical survey of proteins' resistance to constant speed stretching is performed for a set of 17 134 proteins as described by a structure-based model. The proteins selected have no gaps in their structure determination and consist of no more than 250 amino acids. Our previous studies have dealt with 7510 proteins of no more than 150 amino acids. The proteins are ranked according to the strength of the resistance. Most of the predicted top-strength proteins have not yet been studied experimentally. Architectures and folds which are likely to yield large forces are identified. New types of potent force clamps are discovered. They involve disulphide bridges and, in particular, cysteine slipknots. An effective energy parameter of the model is estimated by comparing the theoretical data on characteristic forces to the corresponding experimental values combined with an extrapolation of the theoretical data to the experimental pulling speeds. These studies provide guidance for future experiments on single molecule manipulation and should lead to selection of proteins for applications. A new class of proteins, involving cystein slipknots, is identified as one that is expected to lead to the strongest force clamps known. This class is characterized through molecular dynamics simulations.Comment: 40 pages, 13 PostScript figure

Cosmic neutrino background detection with PTOLEMY

The PTOLEMY experiment aims at detecting the cosmic neutrino background, generated approximately one second after the Big Bang, in accordance with Standard Cosmology. Given the extremely low energy of these neutrinos, reliable experimental detection can be accomplished through neutrino captures on beta-unstable nuclides, eliminating the need for a specific energy threshold. Tritium implanted on a carbon-based nanostructure emerges as a promising candidate among the various isotopes due to its favorable cross-section and low-endpoint energy. The Ptolemy collaboration plans to integrate a solid-state tritium source with a novel compact electro-magnetic filter, based on the dynamic transverse momentum cancellation concept. This filter will be employed in conjunction with an event-based preliminary radio-frequency preselection. The measurement of neutrino mass and the exploration of light sterile neutrinos represent additional outcomes stemming from the Ptolemy experiment’s physics potential, even when utilizing smaller or intermediate-scale detectors. To finalize the conceptualization of the detector, a demonstrator prototype will be assembled and tested at LNGS in 2024. This prototype aims at addressing the challenging aspects of the Ptolemy experimen

Psycho-educational group therapy in acute psychiatric units: creating a psychosocial culture. An update of spread and effectiveness of a psychosocial intervention in Italian psychiatric wards

The implementation of a Cognitive-Behavioural Group Intervention (CBGI) in Italian general hospital psychiatric units started in the years 2000-2001 in two Italian regions. Over the years it has became more and more popular also in other psychiatric units located in the rest of the country. Based on the "stress-vulnerability-coping" theory, the CBGI is a replicable and innovative psychosocial intervention that promotes the active involvement of inpatients in decisions concerning their individual objectives and care. In the present article, the authors briefly describe this intervention and the main findings regarding its implementation in several psychiatric units in different Regions of Italy. The authors emphasize that such a psychosocial approach to inpatient care is needed because it can produce improved clinical outcomes, reduction in untoward events and increased staff and inpatient satisfaction. However, its introduction and use still represent a major cultural and managerial challenge in our country

Local field factors in a polarized two-dimensional electron gas

We derive approximate expressions for the static local field factors of a spin polarized two-dimensional electron gas which smoothly interpolate between their small- and large-wavevector asymptotic limits. For the unpolarized electron gas, the proposed analytical expressions reproduce recent diffusion Monte Carlo data. We find that the degree of spin polarization produces important modifications to the local factors of the minority spins, while the local field functions of the majority spins are less affected.Comment: 8 pages, 10 figure