The PPARgamma agonist pioglitazone modifies the vascular sodium-angiotensin II relationship in insulin-resistant rats.

Glitazones are efficient insulin sensitizers that blunt the effects of angiotensin II (ANG II) in the rat. Sodium chloride is another important modulator of the systemic and renal effects of ANG II. Whether glitazones interfere with the interaction between sodium and the response to ANG II is not known. Therefore, we investigated the effects of pioglitazone on the relationship between sodium and the systemic and renal effects of ANG II in rats. Pioglitazone, or vehicle, was administered for 4 wk to 8-wk-old obese Zucker rats. Animals were fed a normal-sodium (NS) or a high-sodium (HS) diet. Intravenous glucose tolerance tests, systemic and renal hemodynamic responses to ANG II, and the renal ANG II binding and expression of ANG II type 1 (AT(1)) receptors were measured. The results of our study were that food intake and body weight increased, whereas blood pressure, heart rate, filtration fraction, and insulin levels decreased significantly with pioglitazone in obese rats on both diets. Pioglitazone blunted the systemic response to ANG II and abolished the increased responsiveness to ANG II induced by a HS diet. Pioglitazone modified the renal hemodynamic response to changes in salt intake while maintaining a lower filtration fraction with ANG II perfusion. These effects were associated with a decrease in the number and expression of the AT(1) receptor in the kidney. In conclusion, these data demonstrate that the peroxisome proliferator-activated receptor-gamma agonist pioglitazone modifies the physiological relationship between sodium chloride and the response to ANG II in insulin-resistant rats.

Prise en charge des endométriomes et de l'endométriose recto-vaginate et vésicate [Management of endometrioma, recto-vaginal and bladder endometriosis].

Endometriosis is a frequent, benign, chronic disease associated with pain and/or infertility. Classically the lesions are found on the pelvic peritoneum, ovary (endometrioma), rectovaginal septum and bladder. Management of endometrioma has evolved over the last few years to individualised treatment. Indeed endometrioma cystectomy can decrease pain and the risk of recurrence but is also associated with a decrease in ovarian reserve. A multi-disciplinary team should manage recto-vaginal or bladder endometriosis. Surgical resection of these lesions must be as complete as possible and can be complex.

Are commuting and residential mobility decisions simultaneous? : the case of Catalonia (Spain)

In this paper we study the commuting and moving decisions of workers in Catalonia (Spain) and its evolution in the 1986-1996 period. Using a microdata sample from the 1991 Spanish Population Census, we estimate a simultaneous, discrete choice model of commuting and moves, thus indirectly addressing the home and job location decisions. The econometrical framework is a simultaneous, binary probit model with a commute equation and a move equation

Conduction mechanisms and charge storage in Si-nanocrystals metal-oxide-semiconductor memory devices studied with conducting atomic force microscopy

In this work, we demonstrate that conductive atomic force microscopy (C-AFM) is a very powerful tool to investigate, at the nanoscale, metal-oxide-semiconductor structures with silicon nanocrystals (Si-nc) embedded in the gate oxide as memory devices. The high lateral resolution of this technique allows us to study extremely small areas ( ~ 300nm2) and, therefore, the electrical properties of a reduced number of Si-nc. C-AFM experiments have demonstrated that Si-nc enhance the gate oxide electrical conduction due to trap-assisted tunneling. On the other hand, Si-nc can act as trapping centers. The amount of charge stored in Si-nc has been estimated through the change induced in the barrier height measured from the I-V characteristics. The results show that only ~ 20% of the Si-nc are charged, demonstrating that the electrical behavior at the nanoscale is consistent with the macroscopic characterization.

The effects of electron-hole separation on the photoconductivity of individual metal oxide nanowires

The responses of individual ZnO nanowires to UV light demonstrate that the persistent photoconductivity (PPC) state is directly related to the electron¿hole separation near the surface. Our results demonstrate that the electrical transport in these nanomaterials is influenced by the surface in two different ways. On the one hand, the effective mobility and the density of free carriers are determined by recombination mechanisms assisted by the oxidizing molecules in air. This phenomenon can also be blocked by surface passivation. On the other hand, the surface built-in potential separates the photogenerated electron¿hole pairs and accumulates holes at the surface. After illumination, the charge separation makes the electron¿hole recombination difficult and originates PPC. This effect is quickly reverted after increasing either the probing current (self-heating by Joule dissipation) or the oxygen content in air (favouring the surface recombination mechanisms). The model for PPC in individual nanowires presented here illustrates the intrinsic potential of metal oxide nanowires to develop optoelectronic devices or optochemical sensors with better and new performances.

Asymptotic analysis of the Gunn effect with realistic boundary conditions

A general asymptotic analysis of the Gunn effect in n-type GaAs under general boundary conditions for metal-semiconductor contacts is presented. Depending on the parameter values in the boundary condition of the injecting contact, different types of waves mediate the Gunn effect. The periodic current oscillation typical of the Gunn effect may be caused by moving charge-monopole accumulation or depletion layers, or by low- or high-field charge-dipole solitary waves. A new instability caused by multiple shedding of (low-field) dipole waves is found. In all cases the shape of the current oscillation is described in detail: we show the direct relationship between its major features (maxima, minima, plateaus, etc.) and several critical currents (which depend on the values of the contact parameters). Our results open the possibility of measuring contact parameters from the analysis of the shape of the current oscillation.

Boron extraction and vertical mobility in Paraná State oxisol, Brazil

The deficiency or excess of micronutrients has been determined by analyses of soil and plant tissue. In Brazil, the lack of studies that would define and standardize extraction and determination methods, as well as lack of correlation and calibration studies, makes it difficult to establish limits of concentration classes for analysis interpretation and fertilizer recommendations for crops. A specific extractor for soil analysis is sometimes chosen due to the ease of use in the laboratory and not in view of its efficiency in determining a bioavailable nutrient. The objectives of this study were to: (a) evaluate B concentrations in the soil as related to the fertilizer rate, soil depth and extractor; (b) verify the nutrient movement in the soil profile; (c) evaluate efficiency of Hot Water, Mehlich-1 and Mehlich-3 as available B extractors, using sunflower as test plant. The experimental design consisted of complete randomized blocks with four replications and treatments of five B rates (0, 2, 4, 6, and 8 kg ha-1) applied to the soil surface and evaluated at six depths (0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20, 0.20-0.30, and 0.30-0.40 m). Boron concentrations in the soil extracted by Hot Water, Mehlich-1 and Mehlich-3 extractors increased linearly in relation to B rates at all depths evaluated, indicating B mobility in the profile. The extractors had different B extraction capacities, but were all efficient to evaluate bioavailability of the nutrient to sunflower. Mehlich-1 and Mehlich-3 can therefore be used to analyze B as well as Hot Water.

The relationship of capitalization period length with market portfolio composition and betas

Beta coefficients are not stable if we modify the observation periods of the returns. The market portfolio composition also varies, whereas changes in the betas are the same, whether they are calculated as regression coefficients or as a ratio of the risk premiums. The instantaneous beta, obtained when the capitalization frequency approaches infinity, may be a useful tool in portfolio selection.

Phloem mobility of Boron in two eucalypt clones

Boron deficiency causes large productivity losses in eucalypt stands in extensive areas of the Brazilian Cerrado region, thus understanding B mobility is a key step in selecting genetic materials that will better withstand B limitation. Thus, in this study B mobility was evaluated in two eucalypt clones (68 and 129), under B sufficiency or B deficiency, after foliar application of the 10B isotope tracer to a single mature leaf. Samples of young tissue, mature leaves and roots were collected 0, 1, 5, 12 and 17 days after 10B application. The 10B:11B isotope ratio was determined by HR-ICP-MS. Samples of leaves and xylem sap were collected for the determination of soluble sugars and polyalcohols by ion chromatography. Boron was translocated within eucalypt. Translocation of foliar-applied 10B to the young tissues, mature leaves and roots was higher in clone 129 than in 68. Seventeen days after 10B application to a single mature leaf, between 14 and 18 % of B in the young tissue was originated from foliar B application. In plants with adequate B supply the element was not translocated out of the labeled leaf.

Boron mobility in eucalyptus clones

Understanding the magnitude of B mobility in eucalyptus may help to select clones that are more efficient for B use and to design new practices of B fertilization. This study consisted of five experiments with three eucalyptus clones (129, 57 and 58) where the response to and mobility of B were evaluated. Results indicated that clone 129 was less sensitive to B deficiency than clones 68 and 57, apparently due to its ability to translocate B previously absorbed via root systems to younger tissues when B in solution became limiting. Translocation also occurred when B was applied as boric acid only once to a single mature leaf, resulting in higher B concentration in roots, stems and younger leaves. The growth of B-deficient plants was also recovere by a single foliar application of B to a mature leaf. This mobility was greater, when foliar-applied B was supplied in complexed (boric acid + manitol) than in non-complexed form (boric acid alone). When the root system of clone 129 was split in two solution compartments, B supplied to one root compartment was translocated to the shoot and back to the roots in the other compartment, improving the B status and growth. Thus, it appears that B is relatively mobile in eucalyptus, especially in clone 129, and its higher mobility could be due to the presence of an organic compound such as manitol, able to complex B.

Inter-firm labor mobility and knowledge diffusion: a theoretical approach

[cat] Analitzem una economia amb dues característiques principals: la mobilitat dels treballadors implica transferència de coneixement i la productivitat de l’empresa augmenta amb l’intercanvi de coneixement. Cada empresa desenvolupa un tipus de coneixement que serà trasmès a la resta de la indústria mitjançant la mobilitat de treballadors. Estudiem dues estructures de mercat laboral i utilitzant un anàlisi comparatiu derivem les implicacions del model. Els resultats revelen com la mobilitat de treballadors depèn en la varietat i nivell del coneixement, la presència de costos de mobilitat, les institucions, la capacitat d’absorvir coneixement per part de les empreses i la mida de la indústria. Els resultats no depenen de l’estructura del mercat laboral.

Properties of top soil and the relationship between soil and trees in a boreal Scots pine stand

Summary

Prise en charge actuelle de l'incontinence anale [Current management of anal incontinence]

Even though anal incontinence affects a significant proportion of the population, causing a major burden to both patient and society, it still remains "the last closet issue". Less than a third of patients will share this problem with their physician. Consequently, the incidence of anal incontinence is difficult to determine, varying from 2-50%. Since this disabling condition is often associated with urinary incontinence and/or pelvic organ prolapse, a multidisciplinary team approach is required. A wide range of therapeutic options are available. When dietary, medical and rehabilitative treatments have failed, sacral neuromodulation should be considered in selected cases. More invasive surgery is usually undertaken in the presence of major structural defects. The aim of this article is to suggest a comprehensive way of identifying and treating anal incontinence.

Are commuting and residential mobility decisions simultaneous? : the case of Catalonia (Spain)

In this paper we study the commuting and moving decisions of workers in Catalonia (Spain) and its evolution in the 1986-1996 period. Using a microdata sample from the 1991 Spanish Population Census, we estimate a simultaneous, discrete choice model of commuting and moves, thus indirectly addressing the home and job location decisions. The econometrical framework is a simultaneous, binary probit model with a commute equation and a move equation