Study of thermometers for measuring a microcanonical phase transition in nuclear fragmentation

The aim of this work is to study how the thermodynamic temperature is related to the known thermometers for nuclei especially in view of studying the microcanonical phase transition. We find within the MMMC-model that the "S-shape" of the caloric equation of state e^*(T) which is the signal of a phase transition in a system with conserved energy, can be seen in the experimentally accessible slope temperatures T_slope for different particle types and also in the isotopic temperatures T_He-Li. The isotopic temperatures T_H-He are weaker correlated to the shape of the thermodynamic temperature and therefore are less favorable to study the signal of a microcanonical phase transition. We also show that the signal is very sensitive to variations in mass of the source

Production of hypertritons in heavy ion collisions around the threshold of strangeness production

We use the Isospin Quantum Molecular Dynamics approach supplemented with a phase space coalescence to study the properties of the production of hypertritons. We see strong influences of the hyperon rescattering on the yields. The hypertritons show up to be quite aligned to the properties of nuclear matter underlining the necessity of rescattering to transport the hyperons to the spectator matter.Comment: 8 pages, proceedings of 14th International Conference on Nuclear Reaction Mechanisms, Varenna (Italy), 201

Automated reliability assessment for spectroscopic redshift measurements

We present a new approach to automate the spectroscopic redshift reliability assessment based on machine learning (ML) and characteristics of the redshift probability density function (PDF). We propose to rephrase the spectroscopic redshift estimation into a Bayesian framework, in order to incorporate all sources of information and uncertainties related to the redshift estimation process, and produce a redshift posterior PDF that will be the starting-point for ML algorithms to provide an automated assessment of a redshift reliability. As a use case, public data from the VIMOS VLT Deep Survey is exploited to present and test this new methodology. We first tried to reproduce the existing reliability flags using supervised classification to describe different types of redshift PDFs, but due to the subjective definition of these flags, soon opted for a new homogeneous partitioning of the data into distinct clusters via unsupervised classification. After assessing the accuracy of the new clusters via resubstitution and test predictions, unlabelled data from preliminary mock simulations for the Euclid space mission are projected into this mapping to predict their redshift reliability labels.Comment: Submitted on 02 June 2017 (v1). Revised on 08 September 2017 (v2). Latest version 28 September 2017 (this version v3

The Higgs boson and the signal at 750 GeV: Composite particles?

This article explores the possibility that the 125 GeV-mass particle discovered at CERN in 2012 is a composite particle. It then expands the theory to the hypothetical particle seeming to appear at 750 GeV. To that end, this ultra-relativistic quasi-classical model is presented. The results suggest the existence of a tauonium and quarkonia having the required mass

The origins of a new Trypanosoma brucei rhodesiense sleeping sickness outbreak in eastern Uganda.

BACKGROUND: Sleeping sickness, caused by two trypanosome subspecies, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, is a parasitic disease transmitted by the tsetse fly in sub-Saharan Africa. We report on a recent outbreak of T b rhodesiense sleeping sickness outside the established south-east Ugandan focus, in Soroti District where the disease had previously been absent. Soroti District has been the subject of large-scale livestock restocking activities and, because domestic cattle are important reservoirs of T b rhodesiense, we investigated the role of cattle in the origins of the outbreak. METHODS: We identified the origins of cattle entering the outbreak area in the 4 years preceding the outbreak. A matched case-control study was conducted to assess whether the distance of villages from the main market involved with restocking was a risk factor for sleeping sickness. We investigated the spatial clustering of sleeping sickness cases at the start of the outbreak. FINDINGS: Over 50% (1510 of 2796) of cattle traded at the market were reported to have originated from endemic sleeping sickness areas. The case-control study revealed that distance to the cattle market was a highly significant risk factor for sleeping sickness (p<0.001) and that there was a significant clustering of cases (27 of 28) close to the market at the start of the outbreak (p<0.001). As the outbreak progressed, the average distance of cases moved away from the cattle market (0.014 km per day, 95% CI 0.008-0.020 km per day, p<0.001). INTERPRETATIONS: The results are consistent with the disease being introduced by cattle infected with T b rhodesiense imported to the market from the endemic sleeping sickness focus. The subsequent spread of the disease away from the market suggests that sleeping sickness is becoming established in this new focus. Public health measures directed at controlling the infection in the animal reservoir should be considered to prevent the spread of sleeping sickness

The spatial ecology of free-ranging domestic pigs (Sus scrofa) in western Kenya

Background In many parts of the developing world, pigs are kept under low-input systems where they roam freely to scavenge food. These systems allow poor farmers the opportunity to enter into livestock keeping without large capital investments. This, combined with a growing demand for pork, especially in urban areas, has led to an increase in the number of small-holder farmers keeping free range pigs as a commercial enterprise. Despite the benefits which pig production can bring to a household, keeping pigs under a free range system increases the risk of the pig acquiring diseases, either production-limiting or zoonotic in nature. This study used Global Positioning System (GPS) technology to track free range domestic pigs in rural western Kenya, in order to understand their movement patterns and interactions with elements of the peri-domestic environment. Results We found that these pigs travel an average of 4,340 m in a 12 hr period and had a mean home range of 10,343 m2 (range 2,937–32,759 m2) within which the core utilisation distribution was found to be 964 m2 (range 246–3,289 m2) with pigs spending on average 47% of their time outside their homestead of origin. Conclusion These are the first data available on the home range of domestic pigs kept under a free range system: the data show that pigs in these systems spend much of their time scavenging outside their homesteads, suggesting that these pigs may be exposed to infectious agents over a wide area. Control policies for diseases such as Taenia solium, Trypanosomiasis, Trichinellosis, Toxoplasmosis or African Swine Fever therefore require a community-wide focus and pig farmers require education on the inherent risks of keeping pigs under a free range system. The work presented here will enable future research to incorporate movement data into studies of disease transmission, for example for the understanding of transmission of African Swine Fever between individuals, or in relation to the life-cycle of parasites including Taenia solium

Clustering properties of a type-selected volume-limited sample of galaxies in the CFHTLS

(abridged) We present an investigation of the clustering of i'AB<24.5 galaxies in the redshift interval 0.2<z<1.2. Using 100,000 precise photometric redshifts in the four ultra-deep fields of the Canada-France Legacy Survey, we construct a set of volume-limited galaxy catalogues. We study the dependence of the amplitude and slope of the galaxy correlation function on absolute B-band rest-frame luminosity, redshift and best-fitting spectral type. We find: 1. The comoving correlation length for all galaxies decreases steadily from z~0.3 to z~1. 2. At all redshifts and luminosities, galaxies with redder rest-frame colours have clustering amplitudes between two and three times higher than bluer ones. 3. For bright red and blue galaxies, the clustering amplitude is invariant with redshift. 4. At z~0.5, less luminous galaxies have higher clustering amplitudes of around 6 h-1 Mpc. 5. The relative bias between galaxies with red and blue rest-frame colours increases gradually towards fainter absolute magnitudes. One of the principal implications of these results is that although the full galaxy population traces the underlying dark matter distribution quite well (and is therefore quite weakly biased), redder, older galaxies have clustering lengths which are almost invariant with redshift, and by z~1 are quite strongly biased.Comment: 16 pages, 18 figures, accepted for publication in Astronomy and Astrophysic

Identification of human-infective trypanosomes in animal reservoir of sleeping sickness in Uganda by means of serum-resistance-associated (SRA) gene.

BACKGROUND: The expansion of sleeping sickness caused by Trypanosoma brucei rhodesiense beyond its traditional focus in southeast Uganda has been linked with large-scale livestock restocking. To assess the risk presented to the human population by domestic livestock, human-infective T b rhodesiense must be distinguished from non-human-infective T brucei brucei, since both parasites can be present in cattle. We investigated the use of a simple genetic marker to characterise parasites collected from cattle in villages within the new sleeping sickness focus in Soroti District, Uganda. METHODS: 70 T brucei sl samples of known human infectivity status collected from human beings and cattle in Tororo District, Uganda, from 1989 to 1991 were screened for the presence of the human-serum-resistance-associated (SRA) gene by conventional PCR. In 2000-01, blood samples from 200 randomly selected cattle in six villages and two markets in Soroti District were screened for T brucei sl parasites by PCR; positive samples were screened for the presence of the SRA gene. FINDINGS: The SRA gene was present in all 29 samples from patients with sleeping sickness in Tororo District. Of the 41 samples collected from cattle at the same time, the SRA gene was present in the eight samples that tested resistant to human serum in vitro, whereas it was absent from all 33 isolates that were sensitive to human serum in vitro. Of the 200 cattle sampled in Soroti District, we estimated that up to 18% (95% CI 12-23) were infected with T b rhodesiense. INTERPRETATION: Detection of the SRA gene could provide the basis for a simple diagnostic test to enable targeted control of T b rhodesiense in the domestic livestock reservoir, thereby reducing the public-health burden of sleeping sickness in east Africa