On the Lindemann criterion for quantum clusters at very low temperature.

The Lindemann criterion to discern the solid-like or liquid-like nature of a quantum cluster at T = 0 is discussed. A critical analysis of current Lindemann parameters is presented and a new parameter is proposed that is appropriate to study quantum clusters made of identical particles. A simple model wave function is introduced to fix the range of variation of these parameters. The model presents two extreme limits that correspond to either a liquid-like or a solid-like system; besides, it fulfills the Bose symmetry and also permits evaluations without symmetrization. Variational and diffusion Monte Carlo calculations are also performed for clusters of spinless bosons interacting through Lennard-Jones potentials. It is shown that the liquid-like or solid-like character of quantum clusters at zero temperature cannot be simply established in terms of a single parameter.

Ca impurity in small mixed (4)He-(3)He clusters.

The structure of small mixed helium clusters doped with one calcium atom has been determined within the diffusion Monte Carlo framework. The results show that the calcium atom sits at the (4)He-(3)He interface. This is in agreement with previous studies, both experimental and theoretical, performed for large clusters. A comparison between the results obtained for the largest cluster we have considered for each isotope shows a clear tendency of the Ca atom to reside in a deep dimple at the surface of the cluster for (4)He clusters, and to become fully solvated for (3)He clusters. We have calculated the absorption spectrum of Ca around the 4s4p<--4s(2) transition and have found that it is blueshifted from that of the free-atom transition by an amount that depends on the size and composition of the cluster.

Arteritis de Takayasu como causa de hipertensión secundaria / Takayasu’s arteritis as a cause of secondary hypertension

La baja prevalencia de hipertensión arterial secundaria(HTAS) en la población hipertensa general unido a susbajas tasas de reversibilidad y al ingente número de potencialesetiologías obliga a restringir su búsqueda a colectivosdeterminados y centrar esta búsqueda en lasformas más prevalentes y potencialmente corregibles.Las vasculitis son, dentro de las formas de HTAS, muypoco prevalentes. No obstante, su reversibilidad espotencialmente elevada cuando se detecta en fasestempranas; sin embargo, una vez en fase residual fibrótica,la lesión es irreversible. Presentamos un casode HTA debida a arteritis de Takayasu (AT), entidaden la que una de las formas principales de presentaciónes la HTA. El interés de su detección aún en fasefibrótica reside en que la población con esta arteritises joven (por definición, menor de 40 años) y con unriesgo cardiovascular incrementado derivado probablementede la disfunción endotelial asociada a lasvasculitis en general, así como a la rigidez arterial derivada.Se discute el diagnóstico diferencial de las aortitis,se incide en las formas más prevalentes en nuestromedio y se hace hincapié en el manejo terapéuticocomo pacientes de riesgo cardiovascular (RCV) incrementado.Siendo la AT una forma altamente infrecuentede HTAS, el que afecte a pacientes jóvenes yel que el diagnóstico de sospecha sea tan sencillo comola palpación de pulsos periféricos y el registro, almenos inicial, de los valores de PA en ambas extremidadessuperiores no hace sino recordarnos la importanciade seguir las guías terapéuticas a la hora deevaluar al paciente hipertenso general (AU)

The low prevalence of secondary hypertension (SH)in the overall hypertensive population, together withthe low rates of reversibility and the vast number ofpotential etiologies for this condition, makes it necessaryto limit the search to determinate groups and tofocus on the most prevalent and potentially correctabletypes. Although the vasculitides are not prevalent,they have potentially high reversibility when detectedin the early stages; however, lesions in the fibrotic residualstage are irreversible. We present a case of SHdue to Takayasu’s arteritis (TA), a disease in whichSH is one of the main presenting signs. It is importantto detect TA, even in the fibrotic stage, because TAaffects young people (by definition, under 40 years ofage) and involves increased cardiovascular risk, probablydue to the endothelial dysfunction that is associatedwith the vasculitides in general as well as to thearterial stiffness they cause. We discuss the differentialdiagnosis of aortitis and emphasize the most prevalenttypes in our environment and the therapeutic managementfor these patients with increased cardiovascularrisk. The fact that TA is a very rare type of SH thataffects young patients and that the diagnosis can besuspected simply palpating the peripheral pulses andrecording, at least at first, blood pressure in both arms,underlines the importance of following the recommendationsof the therapeutic guidelines when evaluatinggeneral hypertensive patients (AU)

Absceso epidural espinal con espondilitis. Descripción de un caso / Spinal epidural absceso with spondylitis. Case report]

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The spectra of mixed 3He-4He droplets.

The diffusion Monte Carlo technique is used to calculate and analyze the excitation spectrum of 3He atoms bound to a cluster of 4He atoms by using a previously determined optimum filling of single-fermion orbits with well-defined orbital angular momentum L, spin S, and parity quantum numbers. The study concentrates on the energies and shapes of the three kinds of states for which the fermionic part of the wave function is a single Slater determinant: maximum L or maximum S states within a given orbit, and fully polarized clusters. The picture that emerges is that of systems with strong shell effects, whose binding and excitation energies are essentially determined by averages over configuration at fixed number of particles and spin, i.e., by the monopole properties of an effective Hamiltonian.

Stability of small mixed clusters of 4He and 3He atoms.

The existence of small helium clusters containing a variable number of 4He and 3He atoms is studied within a variational Monte Carlo calculation employing the Aziz HFD-B(HE) pair interaction. The clusters 4He(2) support one and two 3He atoms; however, the system with three 3He atoms is metastable, and the next bound system requires at least 18 fermions. All clusters obtained by adding 3He atoms to the trimer 4He(3) and the tetramer 4He(4) are bound, but the clusters 4He(3)-3He(3,4,5) and 4He(3,4)-3He(9) are metastable. All remaining clusters with three or more bosons and any number of fermions are stable.

Cómo clasificar la fibrilación auricular de un modo clínicamente útil / as classifying the atrial fibrilation in a way clinically useful

Actualmente existe un renovado interés en lo que concierne a la fibrilación auricular (FA), avalado por el gran número de publicaciones dedicadas a su estudio y tratamiento, pero en ellas se emplean distintas nomenclaturas para referirse a un mismo tipo de FA o se la define de forma diferente, lo que crea un estado de confusión en la comunidad científica. Además, la FA adopta múltiples formas de presentación clínica, por lo que hay muchas clasificaciones posibles de la misma, lo que hace que no se disponga de una clasificación y nomenclatura acordadas para referirse a sus formas de presentación, y por tanto existe la necesidad de una clasificación sistemática, que sea clínicamente útil, que emplee una nomenclatura uniforme y que, a su vez, clasifique los distintos subtipos de pacientes en orden a un manejo terapéutico específico. El propósito del presente artículo es revisar el estado actual de las clasificaciones de la FA para ayudar al cardiólogo clínico a encuadrar, de la forma más científica y didáctica posible, las distintas maneras de presentarse la FA que observa en su quehacer diario (AU)

Variational study of 3He droplets

We report variational calculations of energies of (3)He(N) droplets ( 20

Incidence of inflammatory bowel disease in the 02 health area of Castellón (1992-1996).

OBJECTIVES: to evaluate the incidence and distribution of inflammatory bowel disease (IBD) in the 02 health area of the province of Castellon. METHODS: retrospective study of 133 cases of inflammatory bowel disease (in 72 males and 61 females aged 13 to 86 years), diagnosed during the period from 1992 to 1996 in an eminently rural area with a population of 349,318 inhabitants. RESULTS: the incidence of IBD was 9.5 cases/100,000 inhabitants/year (6.8, 1.9 and 0.8 cases/100,000 inhabitants/year for ulcerative colitis, Crohn's disease and indeterminate colitis respectively). Incidence was similar in males and females (sex ratio 1.18:1), and average age was 40.9 years (42.6, 35.8 and 38.6 for ulcerative colitis, Crohn's disease and indeterminate colitis respectively). The predominant clinical forms were rectosigmoiditis in ulcerative colitis, granulomatous colitis and terminal colitis in Crohn's disease and proctosigmoiditis in indeterminate colitis. CONCLUSION: the incidence and the forms of presentation of IBD in the 02 health area of the province of Castellon are similar to those reported in the rest of Spain, mainly in the urban population.

Incidence of inflammatory bowel disease in the 02 health area of Castellon (1992-1996).

OBJECTIVES: To evaluate the incidence and distribution of inflammatory bowel disease (IBD) in the 02 health area of the province of Castellon. METHODS: Retrospective study of 133 cases of inflammatory bowel disease (in 72 males and 61 females aged 13 to 86 years), diagnosed during the period from 1992 to 1996 in an eminently rural area with a population of 349,318 inhabitants. RESULTS: The incidence of IBD was 9.5 cases/100,000 inhabitants/year (6.8, 1.9 and 0.8 cases/100,000 inhabitants/year for ulcerative colitis, Crohn's disease and indeterminate colitis respectively). Incidence was similar in males and females (sex ratio 1.18:1), and average age was 40.9 years (42.6, 35.8 and 38.6 for ulcerative colitis, Crohn's disease and indeterminate colitis respectively). The predominant clinical forms were rectosigmoiditis in ulcerative colitis, granulomatous colitis and terminal colitis in Crohn's disease and proctosigmoiditis in indeterminate colitis. CONCLUSION: The incidence and the forms of presentation of IBD in the 02 health area of the province of Castellon are similar to those reported in the rest of Spain, mainly in the urban population.

[Gastric carcinoma in patients younger than 30 years of age. Report of 11 cases]. / Carcinoma gástrico en pacientes menores de 30 años. Presentación de once casos.

Eleven cases of gastric carcinoma occurring in patients younger than 30 years were found in a pool of 929 diagnosed in Hospital General de Castelló during the period of 1976 to 1995. Ten patients were male (10/11). The mean age was 26.9 years. In eight cases precancerous lesions were present. The mean time between diagnosis and surgery was 9 months. The most frequent location was the antrum (63.6%) and the most common histology was gastric/diffuse adenocarcinoma of signet-ring cell type (45.5%). Amplified partial gastrectomy was performed in 81.8%, with Billroth II anastomosis in 36.4%. Immediate postoperative mortality rate was 9.1% and the overall mean survival 56 months, being of 54% and 36% at two and five years, respectively.

[Incidence of gastric cancer in the 02 health area of Castellon]. / Incidencia de cáncer gástrico en el área de salud 02 de Castellón.

We retrospectively reviewed 169 cases of gastric carcinoma diagnosed between 1992 and 1994 in a population of 349,318 inhabitants included in Health Zone 02 in the province of Castellon. These 169 cases correspond to an incidence ratio of 16.1 cases/100,000 inhabitants/year. Males were affected more frequently than females in a 2/1 ratio. Additionally, a male predominance exists at younger ages, however below the age of 30 the incidence in males and females was similar. Pathologic findings showed that the diffuse type gastric adenocarcinoma was more frequently encountered (57.4%) than the Lauren's intestinal type. Overall, the risk of gastric adenocarcinoma in the zones that was studied was higher than in the other two provinces of the Comunidad Valenciana.