Chiral symmetry breaking and stability of strangelets

We discuss the stability of strangelets by considering dynamical chiral symmetry breaking and confinement. We use a $U(3)_{L} \times U(3)_{R}$ symmetric Nambu--Jona-Lasinio model for chiral symmetry breaking supplemented by a boundary condition for confinement. It is shown that strangelets with baryon number $A < 2 \times 10^{3}$ can stably exist. For the observables, we obtain the masses and the charge-to-baryon number ratios of the strangelets. These quantities are compared with the observed data of the exotic particles.Comment: 10 pages, 9 figures, submitted to Physical Review

Time-reversal method and cross-correlation techniques by normal mode theory: a three-point problem

International audienceSince its beginning in acoustics, the Time-Reversal method (hereafter referred as TR) has been explored by different studies to locate and characterize seismic sources in elastic media. But few authors have proposed an analytical analysis of the method, especially in the case of an elastic medium and for a finite body such as the Earth. In this paper, we use a normal mode approach (for general 3-D case and degenerate modes in 1-D reference model) to investigate the convergence properties of the TR method. We first investigate a three-point problem, with two fixed points which are the source and the receiver and a third one corresponding to a changing observation point. We extend the problem of a single channel TR experiment to a multiple channel and multiple station TR experiment. We show as well how this problem relates to the retrieval of Green's function with a multiple source cross-correlation and also the differences between TR method and cross-correlation techniques. Since most of the noise sources are located close to the surface of the Earth, we show that the time derivative of the cross-correlation of long-period seismograms with multiple sources at the surface is different from the Green's function. Next, we show the importance of a correct surface-area weighting of the signal resent by the stations according to a Voronoi tessellation of the Earth surface. We use arguments based on the stationary phase approximation to argue that phase-information is more important than amplitude information for getting a good focusing in TR experiment. Finally, by using linear relationships between the time-reversed displacement (resp. strain wavefields) and the components of a vector force source (resp. a moment tensor source), we show how to retrieve force (or moment tensor components) of any long period tectonic or environmental sources by time reversal

Effects of cytomegalovirus infection in human neural precursor cells depend on their differentiation state

© 2015, Journal of NeuroVirology, Inc. Cytomegalovirus (CMV) is the most common cause of congenital infection in developed countries and a major cause of neurological disability in children. Although CMV can affect multiple organs, the most important sequelae of intrauterine infection are related to lesions of the central nervous system. However, little is known about the pathogenesis and the cellular events responsible for neuronal damage in infants with congenital infection. Some studies have demonstrated that neural precursor cells (NPCs) show the greatest susceptibility to CMV infection in the developing brain. We sought to establish an in vitro model of CMV infection of the developing brain in order to analyze the cellular events associated with invasion by this virus. To this end, we employed two cell lines as a permanent source of NPC, avoiding the continuous use of human fetal tissue, the human SK-N-MC neuroblastoma cell line, and an immortalized cell line of human fetal neural origin, hNS-1. We also investigated the effect of the differentiation stage in relation to the susceptibility of these cell lines by comparing the neuroblastoma cell line with the multipotent cell line hNS-1. We found that the effects of the virus were more severe in the neuroblastoma cell line. Additionally, we induced hNS-1 to differentiate and evaluated the effect of CMV in these differentiated cells. Like SK-N-MC cells, hNS-1-differentiated cells were also susceptible to infection. Viability of differentiated hNS-1 cells decreased after CMV infection in contrast to undifferentiated cells. In addition, differentiated hNS-1 cells showed an extensive cytopathic effect whereas the effect was scarce in undifferentiated cells. We describe some of the effects of CMV in neural stem cells, and our observations suggest that the degree of differentiation is important in the acquisition of susceptibility.CONACYT (CB16782 and #120452), PROMEP (103.5/10/7697), and FAI-UASLP (C12-FAI-03-62.62).Peer Reviewe

Can cosmic strangelets reach the earth?

The mechanism for the propagation of strangelets with low baryon number through the atmosphere of the Earth has been explored. It has been shown that under suitable initial conditions, such strangelets may indeed reach depths near mountain altitudes with mass numbers and charges close to the observed values in cosmic ray experiments.Comment: RevTeX text, with 3 encoded eps figures. To appear in Physical Review Letter

Extensão e organização da diversidade genética da coleção brasileira de germoplasma de Elaeis oleifera.

Objetivou-se neste trabalho avaliar a dissimilaridade de 206 acessos do Banco Ativo de Germoplasma de E. oleifera mantido pela Embrapa, como forma de investigar a extensão e organização da diversidade genética amostrada nesta coleção

A phase I study of a new polyamine biosynthesis inhibitor, SAM486A, in cancer patients with solid tumours

Because tumour cell proliferation is highly dependent upon up-regulation of de-novo polyamine synthesis, inhibition of the polyamine synthesis pathway represents a potential target for anticancer therapy. SAM486A (CGP 48664) is a new inhibitor of the polyamine biosynthetic enzyme S-adenosylmethionine decarboxylase (SAMDC), more potent and specific than the first-generation SAMDC inhibitor methylglyoxal (bis) guanylhydrazone (MGBG). Preclinical testing confirmed promising antiproliferative activity. In this phase I study, SAM486A was given 4-weekly as a 120 h infusion. 39 adult cancer patients were enrolled with advanced/refractory disease not amenable to established treatments, PS ≤ 2, adequate marrow, liver, renal and cardiac function. Doses were escalated in 100% increments without toxicity in 24 pts from 3 mg m–2cycle–1up to 400 mg m–2cycle–1. At 550 and 700 mg m–2cycle–1reversible dose-limiting neutropenia occurred. Other toxicities included mild fatigue, nausea and vomiting. No objective remission was seen. Pharmakokinetic analysis showed a terminal half-life of approximately 2 days. AUC and Cmax were related to dose; neutropenia correlated with AUC. The recommended dose for further phase II studies on this schedule is 400 mg m–2cycle–1. © 2000 Cancer Research Campaig

Imatinibium dipicrate

In the crystal structure of imatinibium dipicrate [systematic name: 1-methyl-4-(4-{4-methyl-3-[4-(3-pyrid­yl)pyrimidin-2-yl­amino]­anilinocarbon­yl}benz­yl)piperazine-1,4-diium dipicrate], C29H33N7O2+·2C6H2N3O7 −, the imatinibium cation is proton­ated at both of the pyrimidine N atoms. Each of the two picrate anions inter­acts with the diprotonated cation through bifurcated N—H⋯O hydrogen bonds forming R 1 2(6) ring motifs. Also, an R 2 2(24) graph set is formed between the benzamidium –NH– group and the 4-pyridyl N atom inter­acting through N—H⋯N hydrogen-bond inter­actions. Additional weak C—H⋯Cg π-ring and π–π inter­molecular inter­actions are observed which also influence crystal packing

Effect of summer grazing on welfare of dairy cows reared in mountain tie-stall barns

Traditional mountain farms have an important economic, social and environmental role. The Alps management system for dairy cows consists of animals kept indoors from autumn to spring, mostly in tie-stalls, and moved to mountain pasture in summer. The aim of our study was to assess the effect of mountain summer grazing on the welfare of dairy cows housed in tie-stall barns. Twenty-four farms were considered. In twelve of them, animals were reared in tie-stalls and moved to mountain pasture for three months in summer; they were visited three times: (i) four weeks before grazing during the indoor period in the stall; (ii) about three weeks after the start of grazing; and (iii) in the stall, in autumn, at least three weeks after returning from grazing. The other twelve farms kept the animals in tie-stalls all year; they were visited once in autumn. Data were collected following a protocol that considers animal-based measures and structure information on the basis of Quality Welfare Consortium® indications. Data allowed the calculation of both the Animal Needs Index score (ANI 35L) and an overall assessment of the cows' welfare obtained from three general aspects: housing, animal's physical condition, and animal's behaviour. Summer grazing had a significant positive effect on injuries, lameness and animal's rising duration but a negative effect on faeces consistency. Moreover, a reduction of tongue playing was observed. The ANI 35L and the overall assessment did not show significant differences linked to summer grazing, which tended to have a positive but temporary effect on animal behaviour