Experimental and Theoretical Search for a Phase Transition in Nuclear Fragmentation

Phase transitions of small isolated systems are signaled by the shape of the caloric equation of state e^*(T), the relationship between the excitation energy per nucleon e^* and temperature. In this work we compare the experimentally deduced e^*(T) to the theoretical predictions. The experimentally accessible temperature was extracted from evaporation spectra from incomplete fusion reactions leading to residue nuclei. The experimental e^*(T) dependence exhibits the characteristic S-shape at e^* = 2-3 MeV/A. Such behavior is expected for a finite system at a phase transition. The observed dependence agrees with predictions of the MMMC-model, which simulates the total accessible phase-space of fragmentation

Fragmentation Phase Transition in Atomic Clusters II - Coulomb Explosion of Metal Clusters -

We discuss the role and the treatment of polarization effects in many-body systems of charged conducting clusters and apply this to the statistical fragmentation of Na-clusters. We see a first order microcanonical phase transition in the fragmentation of $Na^{Z+}_{70}$ for Z=0 to 8. We can distinguish two fragmentation phases, namely evaporation of large particles from a large residue and a complete decay into small fragments only. Charging the cluster shifts the transition to lower excitation energies and forces the transition to disappear for charges higher than Z=8. At very high charges the fragmentation phase transition no longer occurs because the cluster Coulomb-explodes into small fragments even at excitation energy $\epsilon^* = 0$.Comment: 19 text pages +18 *.eps figures, my e-mail adress: [email protected] submitted to Z. Phys.

Identificación de nematodos gastrointestinales en búfalos faenados en un frigorífico de Corrientes, Argentina

The objective of this work was to identify and quantify the adult specimens of gastrointestinal nematodes in buffaloes slaughtered in Virasoro (Corrientes, Argentina) by means of necropsy of the digestive tract, and through coprological studies, in order to correlate them with the count of eggs per gram of fecal stool and the proportion of parasite genera of third stage larvae of stool culture. A total of 4 necropsies corresponding to young male buffaloes were carried out, of which 50% presented adult specimens of Trichostrongylus sp and Haemonchus sp located only in the abomasum. In the coprological studies, 75% of the samples presented counts of egg per gram of fecal stool, with only 2 cases with the identification of third stage larvae of Haemonchus sp in stool cultures.El objetivo del trabajo fue identificar y cuantificar los ejemplares adultos de nematodos gastrointestinales en los búfalos faenados en el frigorífico de Virasoro (Corrientes) mediante la necropsia parasitaria del tubo digestivo y, por intermedio de estudios coprológicos, correlacionarlos con el recuento de huevos por gramo de materia fecal y la proporción de géneros parasitarios de larvas de tercer estadio de los coprocultivos. Se realizaron en total 4 necropsias parasitarias que correspondieron a búfalos machos jóvenes, de los cuales el 50% presentó ejemplares adultos de Trichostrongylus sp y Haemonchus sp ubicados solamente en el abomaso. En los estudios coprológicos, el 75% de las muestras presentaron recuentos de huevos por gramo de materia fecal, de los cuales únicamente en dos casos se pudieron identificar larvas de tercer estadio de Haemonchus sp en los coprocultivos

A large geometric distortion in the first photointermediate of rhodopsin, determined by double-quantum solid-state NMR

Double-quantum magic-angle-spinning NMR experiments were performed on 11,12-C-13(2)-retinylidene-rhodopsin under illumination at low temperature, in order to characterize torsional angle changes at the C11-C12 photoisomerization site. The sample was illuminated in the NMR rotor at low temperature (similar to 120 K) in order to trap the primary photointermediate, bathorhodopsin. The NMR data are consistent with a strong torsional twist of the HCCH moiety at the isomerization site. Although the HCCH torsional twist was determined to be at least 40A degrees, it was not possible to quantify it more closely. The presence of a strong twist is in agreement with previous Raman observations. The energetic implications of this geometric distortion are discussed

Resistencia a los antihelmínticos en bovinos del nordeste de Corrientes (Argentina)

El objetivo del trabajo fue determinar la prevalencia de la resistencia a los antiparasitarios contra los nematodes gastrointestinales de bovinos en el nordeste de Corrientes. El área de estudio comprendió 4 establecimientos ganaderos de los departamentos Ituzaingó y Santo Tomé. El periodo de estudio abarcó de marzo de 2014 a agosto de 2016. La unidad de análisis fue el ternero destete. El método utilizado fue el test de reducción del conteo de huevos. La prevalencia de la resistencia antihelmíntica a la ivermectina en los 4 establecimientos ganaderos muestreados en este estudio fue del 100% y para el benzimidazol fue del 25%. Los géneros parasitarios resistentes a la ivermectina fueron Haemonchus y Cooperia. Estos resultados demuestran un aumento de la resistencia antihelmíntica si se comparan con estudios previos realizados en otros lugares del país

Response to novel objects and foraging tasks by common marmoset (Callithrix Jacchus) female Pairs

Many studies have shown that environmental enrichment can significantly improve the psychological well-being of captive primates, increasing the occurrence of explorative behavior and thus reducing boredom. The response of primates to enrichment devices may be affected by many factors such as species, sex, age, personality and social context. Environmental enrichment is particularly important for social primates living in unnatural social groupings (i.e. same-sex pairs or singly housed animals), who have very few, or no, benefits from the presence of social companions in addition to all the problems related to captivity (e.g. increased inactivity). This study analyses the effects of enrichment devices (i.e. novel objects and foraging tasks) on the behavior of common marmoset (Callithrix jacchus) female pairs, a species that usually lives in family groups. It aims to determine which aspects of an enrichment device are more likely to elicit explorative behaviors, and how aggressive and stress-related behaviors are affected by its presence. Overall, the marmosets explored foraging tasks significantly longer than novel objects. The type of object, which varied in size, shape and aural responsiveness (i.e. they made a noise when the monkey touched them), did not affect the response of the monkeys, but they explored objects that were placed higher in the enclosure more than those placed lower down.Younger monkeys were more attracted to the enrichment devices than the older ones. Finally, stress-related behavior (i.e. scratching) significantly decreased when the monkeys were presented with the objects; aggressive behavior as unaffected. This study supports the importance of environmental enrichment for captive primates and shows that in marmosets its effectiveness strongly depends upon the height of the device in the enclosure and the presence of hidden food. The findings can be explained ifone considers the foraging behavior of wild common marmosets. Broader applications for the research findings are suggested in relation to enrichment

Statistical Multifragmentation of Non-Spherical Expanding Sources in Central Heavy-Ion Collisions

We study the anisotropy effects measured with INDRA at GSI in central collisions of Xe+Sn at 50 A.MeV and Au+Au at 60, 80, 100 A.MeV incident energy. The microcanonical multifragmentation model with non-spherical sources is used to simulate an incomplete shape relaxation of the multifragmenting system. This model is employed to interpret observed anisotropic distributions in the fragment size and mean kinetic energy. The data can be well reproduced if an expanding prolate source aligned along the beam direction is assumed. An either non-Hubblean or non-isotropic radial expansion is required to describe the fragment kinetic energies and their anisotropy. The qualitative similarity of the results for the studied reactions suggests that the concept of a longitudinally elongated freeze-out configuration is generally applicable for central collisions of heavy systems. The deformation decreases slightly with increasing beam energy.Comment: 35 pages, 19 figures, submitted to Nuclear Physics

Consensus statement of the European guidelines on clinical management of HIV-1 tropism testing

Tenth International Congress on Drug Therapy in HIV Infection 7-11 November 2010 Glasgow, UKIntroduction: Testing for HIV tropism is recommended before prescribing a chemokine receptor blocker. To date, in most European countries HIV tropism is determined using a phenotypic test. Recently, new data have emerged supporting the use of a genotypic HIV V3-loop sequence analysis as the basis for tropism determination. The European guidelines group on clinical management of HIV-1 tropism testing was established to make recommendations to clinicians and virologists. Methods: We searched online databases for articles from Jan 2006 until March 2010 with the terms: tropism or CCR5-antagonist or CCR5 antagonist or maraviroc or vicriviroc. Additional articles and/or conference abstracts were identified by hand searching. This strategy identified 712 potential articles and 1240 abstracts. All were reviewed and finally 57 papers and 42 abstracts were included and used by the panel to reach a consensus statement. Results: The panel recommends HIV-tropism testing for the following indications: i) drug-naïve patients in whom toxicity or limited therapeutic options are foreseen; ii) patients experiencing therapy failure whenever a treatment change is considered. Both the phenotypic Enhanced Trofile assay (ESTA) and genotypic population sequencing of the V3-loop are recommended for use in clinical practice. Although the panel does not recommend one methodology over another it is anticipated that genotypic testing will be used more frequently because of its greater accessibility, lower cost and shorter turnaround time. The panel also provides guidance on technical aspects and interpretation issues. If using genotypic methods, triplicate PCR amplification and sequencing testing is advised using the G2P interpretation tool (clonal model) with an FPR of 10%. If the viral load is below the level of reliable amplification, proviral DNA can be used, and the panel recommends performing triplicate testing and use of an FPR of 10%. If genotypic DNA testing is not performed in triplicate the FPR should be increased to 20%. Conclusions: The European guidelines on clinical management of HIV-1 tropism testing provide an overview of current literature, evidence-based recommendations for the clinical use of tropism testing and expert guidance on unresolved issues and current developments. Current data support both the use of genotypic population sequencing and ESTA for co-receptor tropism determination. For practical reasons genotypic population sequencing is the preferred method in Europe.Ye

Abnormal cognition, sleep, EEG and brain metabolism in a novel knock-in Alzheimer mouse, PLB1

Peer reviewedPublisher PD