The behaviour of PIV tracers in a homogeneous environment

The Particle Image Velocimetry (PIV), a technique which is today completely developed, relies on the measured light scattered by suitable particles suspended in the flow. The choice of the proper tracers depends on the experiment type too: in the stratified one, according to the long time required for the preparation, it is very important to be sure to have the correct seeding density at the measurement time. For this reason it is very important to know well the tracers behaviour. In fact it can depend not only on the tracers type and size but also on the interaction with the environment in which they are used. In this work a preliminary study has been developed in order to check the tracers behaviour under different water conditions and with a simplified experimental set-up

HYDROMETEORS PRODUCTION AND ADVECTION IN A GRAVITY WAVE ENVIRONMENT

Production and advection of precipitating water in a prescribed, time dependent flow is investigated by means of a simple 2D model in order to predict the periodical behaviour of rain rate and pressure which was observed in the Po valley during IOP8 of MAP. The (x,z,t)-dependent wave perturbations on wind and temperature fields were derived from a linear stability analysis and are superimposed on z-dependent background fields. The wave influence on the hydrometeors production and advection is discussed

Cyclone-anticyclone asymmetry in rotating thin fluid layers

We report of a series of laboratory experiments and numerical simulations of freely-decaying rotating turbulent flows confined in domains with variable height. We show that the vertical confinement has important effects on the formation of large-scale columnar vortices, the hallmark of rotating turbulence, and in particular delays the development of the cyclone-anticyclone asymmetry. We compare the experimental and numerical results face-to-face, showing the robustness of the results.Comment: 12 pages, 10 figure

Molecular characterization of SSS139, a new satellite DNA family in sibling species of the Drosophila buzzatii cluster

We characterized sequences of a novel SSS139 RsaI satellite DNA family in Drosophila gouveai and Drosophila seriema, two members of the Drosophila buzzatii cluster (D. repleta group). The sequences were AT-rich (69%) with a monomer unit length of about 139 bp and contained two direct subrepeats of 14 bp and 16 bp, suggesting that it might have originated by the duplication of smaller sequences. Southern and dot-blot hybridization analyses also detected SSS139 in other Drosophila buzzatii cluster species (D. koepferae, D. antonietae, D. borborema and D. serido) but not in D. buzzatii. These results agree with the marginal phylogenetic position of D. buzzatii within the D. buzzatii cluster.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FINEP - Financiadora de Estudos e Projeto

Italian survey on benign paroxysmal positional vertigo

Benign paroxysmal positional vertigo (BPPV) is the most common type of peripheral vertigo. BPPV often relapses after the first episode, with a recurrence rate between 15% and 50%. To date both the aetiopathogenetic processes that lead to otoconia detachment and the factors that make BPPV a relapsing disease are still unclear, but recent epidemiological studies have shown a possible association with cardiovascular risk factors. The aim of the present study (Sesto Senso Survey) was to evaluate in the Italian population through an observational survey, the main demographic and clinical characteristics of patients with BPPV (first episode or recurrent) with particular focus on the potential cardiovascular risk factors. The survey was conducted in 158 vestibology centres across Italy on 2,682 patients (mean age 59.3 ± 15.0 years; 39.1% males and 60.9% females) suffering from BPPV, from January 2013 to December 2014. The results showed a high prevalence of cardiovascular risk factors such as high blood pressure (55.8%), hypercholesterolaemia (38.6%) and diabetes (17.7%), as well as a family history of cardiovascular disease (49.4%). A high percentage of patients also had hearing loss (42.9%), tinnitus (41.2%), or both (26.8%). The presence of hypertension, dyslipidaemia and pre-existing cardiovascular comorbidities were significantly related to recurrent BPPV episodes (OR range between 1.84 and 2.31). In addition, the association with diabetes and thyroid/autoimmune disease (OR range between 1.73 and 1.89) was relevant. The survey results confirm the significant association between cardiovascular comorbidities and recurrent BPPV and identify them as a potential important risk factor for recurrence of BPPV in the Italian population, paving the way for the evaluation of new therapeutic strategies in the treatment of this disease

Prediction of chemical composition and peroxide value in unground pet foods by near-infrared spectroscopy

The massive development of the pet food industry in recent years has lead to the formulation of hundreds of canine and feline complete extruded foods with the objective of meeting both the needs of the animals and numerous demands from pet owners. In the meantime, highly variable raw material compositions and the industry's new production techniques oblige manufacturers to monitor all phases of the extrusion process closely in order to ensure the targeted composition and quality of the products. This study aimed at evaluating the potential of infrared technology (visible and near-infrared spectrophotometer; 570-1842 nm) in predicting the chemical composition and peroxide value (PV) of unground commercial extruded dog foods. Six hundred and forty-nine commercial extruded dog foods were collected. For each product, an unground aliquot was analysed by infrared instrument while a second aliquot was sent to a laboratory for proximate analysis and PV quantification. The wide range of extruded dog food typologies included in the study was responsible for the wide variability observed within each nutritional trait, especially crude fibre and ash. The mean value of the 208 pet foods sampled for PV quantification was 17.49 mEq O2/kg fat (min 2.2 and max 94.10 mEq O2/kg fat). The coefficients of determination in cross-validation of NIRS prediction models were 0.77, 0.97, 0.83, 0.86, 0.78 and 0.94 for moisture, crude protein, crude fat, crude fibre, ash and nitrogen-free extract (NFE) respectively. PV prediction was less precise, as demonstrated by the coefficient of determination in cross-validation (0.66). The results demonstrated the potential of NIRS in predicting chemical composition in unground samples, with lower accuracy for moisture and ash, while PV prediction models suggest use for screening purposes only

Global well-posedness of the Kirchhoff equation and Kirchhoff systems

This article is devoted to review the known results on global well-posedness for the Cauchy problem to the Kirchhoff equation and Kirchhoff systems with small data. Similar results will be obtained for the initial-boundary value problems in exterior domains with compact boundary. Also, the known results on large data problems will be reviewed together with open problems.Comment: arXiv admin note: text overlap with arXiv:1211.300

Identification of five picorna-like viruses associated with the endangered cave-dwelling bivalve Congeria kusceri (Bole, 1962)

Congeria kusceri is a bivalve mollusk species endemic to the Dinaric Karst, which displays unique adaptations that have allowed its survival in the subterranean environment with small morphological changes compared with its fossil relatives. Anthropic activities have recently impacted the surface flow of the Neretva river, impairing the seasonal water cycle that has characterized the habitat of this species for hundreds of thousands of years. The lack of an adequate water supply, together with pollution from agricultural and farm water runoff, are posing a serious threat to C. kusceri, as evidenced by the sharp population decline observed in several locations during the past few decades. Due to the limited knowledge available about the basic biology of this filter-feeding species, the precise factors that may affect its health status and reproduction and therefore represent a hazard for its conservation are still unclear. Here, through a transcriptomic approach, we describe the nearly-complete genomes of five C. kusceri-associated RNA viruses belonging to the Picornaviridae family and phylogenetically related with picorna-like viruses previously described in other Mollusca. Although it is presently unknown whether these viruses may have a detrimental effect on bivalve health, we observed a significant increase of viral load during the summer seaso