Time Variation of Fine Structure Constant and Proton-Electron Mass Ratio with Quintessence

Recent astrophysical observations of quasar absorption systems indicate that the fine structure constant $\alpha$ and the proton-electron mass ratio $\mu$ may have evolved through the history of the universe. Motivated by these observations, we consider the cosmological evolution of a quintessence-like scalar field $\phi$ coupled to gauge fields and matter which leads to effective modifications of the coupling constants and particle masses over time. We show that a class of models where the scalar field potential $V(\phi)$ and the couplings to matter $B(\phi)$ admit common extremum in $\phi$ naturally explains constraints on variations of both the fine structure constant and the proton-electron mass ratio.Comment: 9 pages, 4 figures, CosPA 2006 Proceeding. 9 pages, 4 figures, CosPA 2006 Proceeding will be published in the Mod. Phys. Lett.

Uso de séries temporais no estudo do mercado de trigo.

Existem diversas metodologias com base em dados de séries temporais aplicáveis a estudos de modelos de previsão. Com o intuito de analisar a evolução do mercado de trigo foram utilizados dois desses modelos, Arima e Espaço de Estados, para previsão das séries: produção, consumo e importação de trigo do Brasil. As séries observadas compreendem o período 1972- 2008 e as previsões se estendem até 2018. Taxas de crescimento também foram calculadas para as séries analisadas. Os resultados obtidos mostram que as projeções da produção e da importação foram as que melhor se ajustaram aos dados. As estimativas indicam perspectivas de crescimento para a produção, o consumo e a importação de trigo. A maior taxa de crescimento foi encontrada para a produção. Conclui-se que o Brasil não conseguirá se tornar auto-suficiente na produção de trigo, mantendo sua dependência em relação aos mercados exportadores, uma vez que o consumo continuará aumentando

Modelling the extremes of seasonal viruses and hospital congestion: The example of flu in a Swiss hospital

Viruses causing flu or milder coronavirus colds are often referred to as ‘seasonal viruses’ as they tend to subside in warmer months. In other words, meteorological conditions tend to impact the activity of viruses, and this information can be exploited for the operational management of hospitals. In this study, we use 3 years of daily data from one of the biggest hospitals in Switzerland and focus on modelling the extremes of hospital visits from patients showing flu-like symptoms and the number of positive flu cases. We propose employing a discrete generalized Pareto distribution for the number of positive and negative cases. Our modelling framework allows for the parameters of these distributions to be linked to covariate effects, and for outlying observations to be dealt with via a robust estimation approach. Because meteorological conditions may vary over time, we use meteorological and not calendar variations to explain hospital charge extremes, and our empirical findings highlight their significance. We propose a measure of hospital congestion and a related tool to estimate the resulting CaRe (Charge-at-Risk-estimation) under different meteorological conditions. The relevant numerical computations can be easily carried out using the freely available GJRM R package. The empirical effectiveness of the proposed method is assessed through a simulation study

Optical Tracer Size Differences Allow Quantitation of Active Pumping Rate Versus Stokes–Einstein Diffusion in Lymphatic Transport

Lymphatic uptake of interstitially administered agents occurs by passive convective–diffusive inflow driven by interstitial concentration and pressure, while the downstream lymphatic transport is facilitated by active propulsive contractions of lymphatic vessel walls. Near-infrared fluorescence imaging in mice was used to measure these central components of lymphatic transport for the first time, using two different-sized molecules––methylene blue (MB) and fluorescence-labeled antibody immunoglobulin G (IgG)-IRDye 680RD. This work confirms the hypothesis that lymphatic passive inflow and active propulsion rates can be separated based upon the relative differences in Stokes–Einstein diffusion coefficient. This coefficient specifically affects the passive-diffusive uptake when the interstitial volume and pressure are constant. Parameters such as mean time-to-peak signal, overall fluorescence signal intensities, and number of active peristaltic pulses, were estimated from temporal imaging data. While the mean time to attain peak signal representative of diffusion-dominated flow in the lymph vessels was 0.6±0.2  min for MB and 8±6  min for IgG, showing a size dependence, the active propulsion rates were 3.4±0.8  pulses/min and 3.3±0.5  pulses/min, respectively, appearing size independent. The propulsion rates for both dyes decreased with clearance from the interstitial injection-site, indicating intrinsic control of the smooth muscles in response to interstitial pressure. This approach to size-comparative agent flow imaging of lymphatic function can enable noninvasive characterization of diseases related to uptake and flow in lymph networks

An Overview of Mitochondrial Protein Defects in Neuromuscular Diseases

none8noNeuromuscular diseases (NMDs) are dysfunctions that involve skeletal muscle and cause incorrect communication between the nerves and muscles. The specific causes of NMDs are not well known, but most of them are caused by genetic mutations. NMDs are generally progressive and entail muscle weakness and fatigue. Muscular impairments can differ in onset, severity, prognosis, and phenotype. A multitude of possible injury sites can make diagnosis of NMDs difficult. Mitochondria are crucial for cellular homeostasis and are involved in various metabolic pathways; for this reason, their dysfunction can lead to the development of different pathologies, including NMDs. Most NMDs due to mitochondrial dysfunction have been associated with mutations of genes involved in mitochondrial biogenesis and metabolism. This review is focused on some mitochondrial routes such as the TCA cycle, OXPHOS, and β-oxidation, recently found to be altered in NMDs. Particular attention is given to the alterations found in some genes encoding mitochondrial carriers, proteins of the inner mitochondrial membrane able to exchange metabolites between mitochondria and the cytosol. Briefly, we discuss possible strategies used to diagnose NMDs and therapies able to promote patient outcomeopenMarra Federica, Lunetti Paola, Curcio Rosita, Lasorsa Francesco Massimo, Capobianco Loredana, Porcelli Vito, Dolce Vincenza, Fiermonte Giuseppe and Scarcia PasqualeMarra, Federica; Lunetti, Paola; Curcio, Rosita; Lasorsa Francesco, Massimo; Capobianco, Loredana; Porcelli, Vito; Dolce, Vincenza; Fiermonte Giuseppe and Scarcia, Pasqual

Current exposure of Italian women of reproductive age to PFOS and PFOA: a human biomonitoring study

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) concentrations were determined in serum samples collected in 2011-2012 from 549 nulliparous Italian women of reproductive age who resided in six different Italian Regions. Assessment of exposure to perfluorinated compounds was part of a large human biomonitoring study (Project Life Plus "Womenbiopop") that aimed at examining the exposure of women of reproductive age to priority organic pollutants. The median concentrations of PFOS and PFOA were 2.43, and 1.55ngg-1, respectively. Significant differences in the concentrations of both compounds were observed among the six Regions. Women from central Italy had the highest levels of both compounds, followed by women from northern Italy, and southern Italy. No differences in the PFOS concentrations were found between women from urban/industrial areas and women from rural areas, whereas the levels of PFOA were significantly higher in women residing in urban/industrial areas than in women residing in rural areas. Taken together, the observed concentrations confirm that the overall exposure of the Italian population is among the lowest observed in industrialized countries. A downward temporal trend in exposure was observed for both compounds when comparing the results from the present study with those assessed in a study conducted in 2008

Effect of age on melanoma risk, prognosis and treatment response

As for all types of cancer, the incidence of melanoma increases with age. However, naevus counts (the principal risk factor for melanoma) decrease with age; hence the relationship between ageing and melanoma is complex. Subjects who maintain a high naevus count after the age of 50 years are more likely to be affected by melanoma, as their lesions do not senesce. Longer telomere length, which is strongly related to age, is linked to high naevus counts/melanoma risk; thus melanoma biology is influenced by factors that slow down ageing. Age is also an important prognostic factor in melanoma. Increasing age leads to worse survival in stages I, II and III. Sentinel lymph node (SLN) status, which is a strong predictor of melanoma survival, is also affected by age, as SLN positivity decreases with age. However, the prognostic value of SLN on survival increases with age, so, again, these relationships are complex. In patients with stage IV melanoma, age impacts on survival because it affects responses to treatment. This review examines the effects of age on melanoma risk, prognostic factors and responses to treatment