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

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

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

Aggregation of measures to produce an overall assessment of animal welfare. Part 1: a review of existing methods

Several systems have been proposed for the overall assessment of animal welfare at the farm level for the purpose of advising farmers or assisting public decision-making. They are generally based on several measures compounded into a single evaluation, using different rules to assemble the information. Here we discuss the different methods used to aggregate welfare measures and their applicability to certification schemes involving welfare. Data obtained on a farm can be (i) analysed by an expert who draws an overall conclusion; (ii) compared with minimal requirements set for each measure; (iii) converted into ranks, which are then summed; or (iv) converted into values or scores compounded in a weighted sum (e.g. TGI35L) or using ad hoc rules. Existing methods used at present (at least when used exclusively) may be insufficiently sensitive or not routinely applicable, or may not reflect the multidimensional nature of welfare and the relative importance of various welfare measures. It is concluded that different methods may be used at different stages of the construction of an overall assessment of animal welfare, depending on the constraints imposed on the aggregation proces

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