Produit de solubilité de la calcite et constantes de dissociation de CaHCO3+ et CaCO30 entre 5 et 75 °C

Les valeurs du produit de solubilité de la calcite et des constantes de dissociation de CaHCO3+ et CaCO30, notées K3 et K4, ont été déterminées à différentes températures comprises entre 5 et 75 °C (la calcite est instable aux températures plus élevées) à partir des mesures [(Ca2+)T, pH] de solubilité de ce sel dans l'eau carboniquement pure. Les résultats obtenus ont permis d'établir les relations empiriques suivantes :pKs= 7,8156 + 0,03111 T + (1 502/T) - 5,518 log TpK3= 6,2447 + 0,00437 T + (864,479/T) - 0,363 log TpK4= 2,89636 + 0,00707 T + (102,87/T) - 0,44176 log Texpressions dans lesquelles T désigne la température absolue (K) et log le logarithme décimal.Des variations de pKS avec la température nous avons déduit, à 25 °C, les grandeurs thermodynamiques relatives à la dissolution de la calcite :∆H0 = -2510 cal. mol-1, ∆S0 = -47,2 cal. mol-1. K-1et ∆C∘p = -73,9 cal. mol-1. K-1The values of the solubility product of calcite and dissociation constants of CaHCO3+ and CaCO30, K3 and K4 respectively, were determined at several temperatures between 5 and 75 °C (calcite becomes unstable at higher temperatures) from measurements [(Ca2+)T, pH] of calcite solubility using carbonically pure water. The results obtained lead to the following empirical expressions for the dependence of equilibrium constants on the temperature :pKs= 7,8156 + 0,03111 T + (1 502/T) - 5,518 log TpK3= 6,2447 + 0,00437 T + (864,479/T) - 0,363 log TpK4= 2,89636 + 0,00707 T + (102,87/T) - 0,44176 log Twhere log T is the common logarithm of the absolute temperature T(K).Using this expression of pKS, the calculated thermodynamic properties of the calcite dissolution reaction at 25 °C are :∆H0 = -2510 cal. mol-1, ∆S0 = -47,2 cal. mol-1. K-1et ∆C∘p = -73,9 cal. mol-1. K-

Resonance modes in a 1D medium with two purely resistive boundaries: calculation methods, orthogonality and completeness

Studying the problem of wave propagation in media with resistive boundaries can be made by searching for "resonance modes" or free oscillations regimes. In the present article, a simple case is investigated, which allows one to enlighten the respective interest of different, classical methods, some of them being rather delicate. This case is the 1D propagation in a homogeneous medium having two purely resistive terminations, the calculation of the Green function being done without any approximation using three methods. The first one is the straightforward use of the closed-form solution in the frequency domain and the residue calculus. Then the method of separation of variables (space and time) leads to a solution depending on the initial conditions. The question of the orthogonality and completeness of the complex-valued resonance modes is investigated, leading to the expression of a particular scalar product. The last method is the expansion in biorthogonal modes in the frequency domain, the modes having eigenfrequencies depending on the frequency. Results of the three methods generalize or/and correct some results already existing in the literature, and exhibit the particular difficulty of the treatment of the constant mode

Méthode de mesure des conductivités bidomaines anisotropes du tissu cardiaque

Les méthodes de mesure d'impédance -- Notions relatives aux tissus biologiques -- Évaluation des paramètres passifs du tissu -- Modèles bidomaines capacitifs pour la mesure des conductivités myocardiques -- Situation de l'article dans la thèse -- Glossary of terms -- The standard bidomain model -- The direct current approach -- The alternating current approach -- Three dimensional Fourier transform solution -- The bidomain model including intracellular capacitance -- Three dimensional numerical bidomain model -- Parameter estimation -- Mesure des conductivités du myocarde avec la technique à huit électrodes dans le domaine fréquentiel -- Measurement theory -- Alternating current bidomain model -- Biodomain model with complex intracellular medium -- La méthode de mesure

Management of natural resources through automatic cartographic inventory

The author has identified the following significant results. Significant results of the ARNICA program (February - December 1973) were: (1) The quantitative processing of ERTS-1 data was developed along two lines: the study of geological structures and lineaments of Spanish Catalonia, and the phytogeographical study of the forest region of the Landes of Gascony (France). In both cases it is shown that the ERTS-1 imagery can be used in establishing zonings of equal quantitative interpretation value. (2) In keeping with the operational transfer program proposed in previous reports between exploration of the imagery and charting of the object, a precise data processing method was developed, concerning more particularly the selection of digital equidensity samples computer display and rigorous referencing

Advanced Medical Image Registration Methods for Quantitative Imaging and Multi-Channel Images

This thesis proposes advanced medical image registration methods for applications that can be grouped in two broad themes. The first theme focuses on registration techniques increasing the reliability of _quantitative measurements_ extracted from sets of medical images. The second theme that is considered in this thesis is the registration of _multi-channel_ images

Spin configurations in Co2FeAl0.4Si0.6 Heusler alloy thin film elements

We determine experimentally the spin structure of half-metallic Co2FeAl0.4Si0.6 Heusler alloy elements using magnetic microscopy. Following magnetic saturation, the dominant magnetic states consist of quasi-uniform configurations, where a strong influence from the magnetocrystalline anisotropy is visible. Heating experiments show the stability of the spin configuration of domain walls in confined geometries up to 800 K. The switching temperature for the transition from transverse to vortex walls in ring elements is found to increase with ring width, an effect attributed to structural changes and consequent changes in magnetic anisotropy, which start to occur in the narrower elements at lower temperatures.Comment: 4 pages, 4 figure

Multiorgan failure after sickle cell vaso occlusive attack: integrated clinical and biological emergency

We describe the case of a 30-year-old patient, suffering from composite S/beta + sickle cell disease. He was hospitalized following a vaso-occlusive attack with acute bone pains. Despite an analgesic treatment and transfusion of three units of red blood cells, a non-regenerative anemia appeared within 24 hours. One day later an acute chest syndrome with atelectasis of the left lung and desaturation and multi-organ failure occurred and necessitated the patient\u27s intubation and required him to be placed in an artificial coma. A bronchoalveolar lavage was performed, which eliminated pneumonia but proved, after staining with oil red O, many neutral fatty acid microvacuoles in more than 80% of macrophages, suggesting a pulmonary fat embolism. The hypothesis of a bone marrow necrosis causing a pulmonary fat embolism was discussed and confirmed the next day by the characteristic appearance of the bone marrow. A therapeutic protocol associating iteratively bleeding and red blood cells transfusion was administered on the second day with the objective of maintaining haemoglobin S at less than 20% rate. Successive haemoglobin S assay was applied using a high performance liquid chromatography (HPLC) technique with a quick response within one hour after transfusion or bleeding. This protocol resulted in an improvement in the patient\u27s condition, with a gradual normalization of vital signs and extubation twelve days later and discharge without sequelae twenty-five days later. The succession of rare but serious sickle cell complications anaemia which occurred in this patient could be controlled by adapting the laboratory for the clinical emergency

Assessment of human enteric viruses in cultured and wild bivalve molluscs

Standard and real-time reverse transcription-PCR (rRT-PCR) procedures were used to monitor cultured and wild bivalve molluscs from the Ría de Vigo (NW Spain) for the main human enteric RNA viruses, specifically, norovirus (NoV), hepatitis Avirus (HAV), astrovirus (AsV), rotavirus (RT), enterovirus (EV), and Aichi virus (AiV). The results showed the presence of at least one enteric virus in 63.4% of the 41 samples analyzed. NoV GII was the most prevalent virus, detected in 53.7% of the samples, while NoV GI, AsV, EV, and RV were found at lower percentages (7.3, 12.2, 12.2, and 4.9%, respectively). In general, samples obtained in the wild were more frequently contaminated than those from cultured (70.6 vs. 58.3%) molluscs and were more readily contaminated with more than one virus. However, NoV GI was detected in similar amounts in cultured and wild samples (6.4 × 102 to 3.3 × 103 RNA copies per gram of digestive tissue) while the concentrations of NoV GII were higher in cultured (from 5.6 × 101 to 1.5 × 104 RNA copies per gram of digestive tissue) than in wild (from 1.3 × 102 to 3.4 × 104 RNA copies per gram of digestive tissue) samples. [Int Microbiol 2009; 12(3):145-151

Norwalk Virus–specific Binding to Oyster Digestive Tissues

Specific binding of virus to oysters can selectively concentrate a human pathogen