Influence of serological factors and BMI on the blood pressure/hematocrit association in healthy young men and women.

The association between mean arterial blood pressure (MAP) and hematocrit (Hct) as a surrogate for blood viscosity was investigated in a young (average 20.0±2.3 years), healthy population of 174 men and 442 women. Health status was assessed by clinical examination and serological evaluation. Individuals with severe anemia or hemoconcentration, prior traumas or major surgical intervention, smokers, and pregnant or lactating women were excluded from the study. The MAP/Hct association was positive and significant (P=0.04) for women and negative, albeit not significantly so, for men. The MAP/Hct association was also evaluated in subgroups of the same population with a progressive step-by-step exclusion of: individuals with cholesterol >200 mg/dL; triglycerides >200 mg/dL; body mass index >25 kg/m(2); and glucose >100 mg/dL. This consecutively reduced the strength of the positive MAP/Hct association in women, which became negative - although not significantly so - when all anomalously high factors were excluded. The same trend was found in men. Our study indicates that previously reported positive trends in the relationship between the MAP and Hct in the population are not present in a young, healthy population of men or women that excludes individuals with the confounding factors of above normal serological values and BMI

Constant of Motion for several one-dimensional systems and outlining the problem associated with getting their Hamiltonians

The constants of motion of the following systems are deduced: a relativistic particle with linear dissipation, a no-relativistic particle with a time explicitly depending force, a no-relativistic particle with a constant force and time depending mass, and a relativistic particle under a conservative force with position depending mass. The problem of getting the Hamiltonian for these systems is determined by getting the velocity as an explicit function of position and generalized linear momentum, and this problem can be solved a first approximation for the first above system.Comment: 15 pages, Te

La administración pública en los estados y reflexiones sobre el federalismo

El federalismo en México, desde su concepción orig i nal en la Constitución de 1824, ha venido transformándose y adecuándose a las nuevas exigencias de estados y municipios para pasar de una centralización a una descentralización, con la finalidad de transferir más facultades y atribuciones del gobierno cen tral hacia otros órdenes gubernamentales. A la par, han surgido organizaciones como la Conferencia Nacional de Gobernadores (Conago) para el caso de los estados, y asociaciones como la Conferencia Nacional de Municipios de México (Conamm) para los municipios, como un contrapeso real para el fortalecimiento del federalismo. A continuación analizaremos algunos aspectos de la descentralización que están contribuyendo a dicho fortalecimiento en México

Direct measurements of the magnetocaloric effect in pulsed magnetic fields: The example of the Heusler alloy Ni50_{50}Mn35_{35}In15_{15}

We have studied the magnetocaloric effect (MCE) in the shape-memory Heusler alloy Ni$_{50}$Mn$_{35}$In$_{15}$ by direct measurements in pulsed magnetic fields up to 6 and 20 T. The results in 6 T are compared with data obtained from heat-capacity experiments. We find a saturation of the inverse MCE, related to the first-order martensitic transition, with a maximum adiabatic temperature change of $\Delta T_{ad} = -7$ K at 250 K and a conventional field-dependent MCE near the second-order ferromagnetic transition in the austenitic phase. The pulsed magnetic field data allow for an analysis of the temperature response of the sample to the magnetic field on a time scale of $\sim 10$ to 100 ms which is on the order of typical operation frequencies (10 to 100 Hz) of magnetocaloric cooling devices. Our results disclose that in shape-memory alloys the different contributions to the MCE and hysteresis effects around the martensitic transition have to be carefully considered for future cooling applications.Comment: 5 pages, 4 figure

Urraca. Un nombre egregio en la onomástica altomedieval

Sin resume

Automatic graph cut based segmentation of retinal optic disc by incorporating blood vessel compensation.

Glaucoma is one of the main causes of blindness worldwide. Periodical retinal screening is highly recommended in order to detect any sign of the disease and apply the appropriated treatment. Different systems for the analysis of retinal images have been designed in order to assist this process. The segmentation of the optic disc is an important step in the development of a retinal screening system. In this paper we present an unsupervised method for the segmentation of the optic disc. The main obstruction in the optic disc segmentation process is the presence of blood vessels breaking the continuity of the object. While many other methods have addressed this problem trying to eliminate the vessels, we have incorporated the blood vessel information into our formulation. The blood vessels inside of the optic disc are used to give continuity to the object to segment. Our approach is based on the graph cut technique, where the graph is constructed by considering the relationship between neighbouring pixels and by the likelihood of them belonging to the foreground and background from prior information. Our method was tested on two public datasets, DIARETDB1 and DRIVE. The performance of our method was measured by calculating the overlapping ratio (Oratio), sensitivity and the mean absolute distance (MAD) with respect to the manually labeled images

Cadmium affects the mitochondrial viability and the acid soluble thiols concentration in liver, kidney, heart and gills of Ancistrus brevifilis (Eigenmann, 1920)

The freshwater fish Ancistrus brevifilis, which is found in Venezuelan rivers, is considered a potential sentinel fish in ecotoxicological studies. The cadmium (Cd) effect on the mitochondrial viability (MV) and acid soluble thiols levels (AST) in A. brevifilis tissues (liver, kidney, heart, and gill) was evaluated. Forty-two fish with similar sizes and weights were randomly selected, of which 7 fish (with their respective replicate) were exposed for 7 and 30 days to a Cd sublethal concentration (0.1 mg.l-1). We determined the MV through a Janus Green B colorimetric assay and we obtained the concentration of AST by Ellman’s method. Mitochondrial viability decreased in fish exposed to Cd for 30 days with the liver being the most affected tissue. We also detected a significant decrease in AST levels was in fishes exposed to Cd for 7 days in liver and kidney tissues; these results suggests that AST levels are elevated in some tissues may act as cytoprotective and adaptive alternative mechanism related to the ROS detoxification, maintenance redox status and mitochondrial viability. Organ-specifics variations were observed in both assays. We conclude that the Cd exposure effect on AST levels and MV, vary across fish tissues and is related to the exposure duration, the molecule dynamics in different tissues, the organism and environmental conditions.Keywords: Ancistrus brevifilis, Cadmium, Soluble thiols, Janus Green B, Mitochondrial viability

Replacing the Transfusion of 1-2 Units of Blood with Plasma Expanders that Increase Oxygen Delivery Capacity: Evidence from Experimental Studies.

At least a third of the blood supply in the world is used to transfuse 1-2 units of packed red blood cells for each intervention and most clinical trials of blood substitutes have been carried out at this level of oxygen carrying capacity (OCC) restoration. However, the increase of oxygenation achieved is marginal or none at all for molecular hemoglobin (Hb) products, due to their lingering vasoactivity. This has provided the impetus for the development of "oxygen therapeutics" using Hb-based molecules that have high oxygen affinity and target delivery of oxygen to anoxic areas. However it is still unclear how these oxygen carriers counteract or mitigate the functional effects of anemia due to obstruction, vasoconstriction and under-perfusion. Indeed, they are administered as a low dosage/low volume therapeutic Hb (subsequently further diluted in the circulatory pool) and hence induce extremely small OCC changes. Hyperviscous plasma expanders provide an alternative to oxygen therapeutics by increasing the oxygen delivery capacity (ODC); in anemia they induce supra-perfusion and increase tissue perfusion (flow) by as much as 50%. Polyethylene glycol conjugate albumin (PEG-Alb) accomplishes this by enhancing the shear thinning behavior of diluted blood, which increases microvascular endothelial shear stress, causes vasodilation and lowering peripheral vascular resistance thus facilitating cardiac function. Induction of supra-perfusion takes advantage of the fact that ODC is the product of OCC and blood flow and hence can be maintained by increasing either or both. Animal studies suggest that this approach may save a considerable fraction of the blood supply. It has an additional benefit of enhancing tissue clearance of toxic metabolites