[en] We have determined the natural radiation level in three types of adhesive cements, five types of concrete and two types of mortars of different strength normally used in the construction field. Of these materials, both concrete and mortars were prepared in our laboratories, cements the contrary were of a commercial nature.

[en] The records of the Radiotherapy Division of the Radiology Department of Vanderbilt University Hospital were reviewed for the years 1952 to 1971. During that period of time, 122 patients with diagnosis of pituitary adenomas were treated by external irradiation. A variety of techniques (2 or 3 stationary fields, 180⁰ rotational fields), equipment (⁶⁰Co, 6 MeV Linac) and fractionation schedules (treating 4, 5 or 6 days per week, doses ranging between 150 and 280 rad per fraction), were used. Five patients developed severe complications: 1 with brain necrosis and 4 with blindness related radiation damage to optic pathways. From analysis of time--dose factors (TDF), it is evident that the risk of complications increases from 0% to 25% as the dose exceeds a TDF of 80. Although a significant increase in success rate has resulted from doses in excess of 3500 rad, there is little support for believing that doses in excess of 5000 rad (TDF 80) achieve improved results

[en] In this paper, we report measurements on the Fermi surface (FS) topology of Bi₂Sr₂CaCu₂O_8+x (Bi-2212) superconductors by angle scanning photoemission spectroscopy using polarized synchrotron radiation. Our k-scanning approach allows us to record the full symmetry of the main features of the FS throughout large portions of the reciprocal space, as well as their dependence on the polarization and energy of the incident light. In the recorded two-dimensional images, we have clearly identified in addition to the principal FS and its 'umklapps' replicas another bands of much smaller intensity, previously reported as 'shadow FS'. The k-dependence of these bands is identical that to the principal FS, but displaced by a wave-vector (π, π). In the present study, we provide a qualitative analysis of this superstructure as well as its relationship with the structural order and the low-energy magnetic fluctuations of these compounds

No abstract available

[en] The Fiambala range is located in the central south part of the province of Catamarca, Western Sierras Pampeanas, Argentina. It is largely conformed by Precambrian metamorphic rocks, a Cambrian granitic intrusive, Ordovician basic and ultra basic rocks and epi zonal Carboniferous granites (Los Ratones, El Salto and Ayacucho Granites). The Carboniferous granites are sub alkaline, weakly peraluminous, high silica (except for the porphyritic facies of Los Ratones granite) and moderately enriched in K. Contents of trace elements and REE indicate that El S alto and Ayacucho granites and the granular facies of Los Ratones granite have characteristics of evolved and differentiated granite associated with hydrothermal systems. The variations of trace elements, particularly Sn, W, U, Rb, Ba, Zr and Sr suggest that they correspond to granites with mineralization potential. Genetically linked to these granites there are Sn, W, U and minor base metals greisen deposits. The hydrothermal process that yield to these deposits involved two main alteration stages, beginning with alkali metasomatism follow by greissenization. According to the isotopic ages the hydrothermal processes postdate about 1 Ma the magmatic activity. The analyses of the granites and the associated greisen deposits confirm that the post orogenic carboniferous magmatism is the major metallogenetic control of the ore deposits from the studied area. This metallogenetic control could be a useful tool in prospecting similar deposits in the rest of the Western Sierras Pampeanas. (Author)

[en] The discovery that certain proteins may require zinc for their activity, and the fact that several of them cannot be purified in large amounts, has led us to develop a rapid, sensitive method to detect these proteins in samples. This method is based on the fractionation of the proteins by gel electrophoresis, blotting onto nitrocellulose paper, and overlaying with ⁶⁵Zn. We have tested the procedure with well-characterized zinc-binding proteins. In the case of tubulin, we have used this method to localize its zinc-binding site. It was found that zinc binds to the first 150 amino acids of both alpha- and beta-tubulin subunits

[en] They are denominated vascular rings to the group of early anomalies of the embryologic development of the aortic arches that they cause a spectrum of clinical manifestations for the compression of the air way and of the digestive tract. The authors report 8 cases presented among 1999-2002, with an average of age of 10 months at the moment of the diagnosis, 6 arches aortic right and two with double aortic arch. The strider from the birth and the syndrome appearance bronchia-obstructive during the first month was presented in all the cases and the digestive manifestations as dysphagia they accompanied to the cases of double aortic arch. The thorax x-ray allowed valuing the aortic arch it forms the shepherd's aortic crook and of the right the artery right subclavian in 62.5%, and the echography in 100% of the cases; the x-ray of digestive roads evidenced fixed notch in 71% of the cases. The echocardiogram allowed evaluating the origin of the glasses anomalous of the shepherd's crook in 62.5%. It was carried out surgical treatment in 87,5% of the cases, with complications pos-surgical in 1/7 consistent in chylethorax, and subcutaneous emphysema. The authors recommend evaluating for vascular ring to everything recently born with strider and rough obstruction by means of thorax x-ray, x-ray of digestive roads and echocardiogram. In selected cases it would be practiced endoscopy of the air way and the aortogram or the magnetic resonance of the thorax and their vessel for confirmation of the definitive diagnosis

[en] The equations of the point kinetics and the models of neutronic noise in the time domain of Alfa-Rossi, Alfa-Feynman and distribution of time intervals pulse to pulse of Babala are discussed. The limits of the models of the experimental measurement of the kinetic parameters of the reactor are discussed: the decay constant of the prompt neutrons for the subcritical and critical state of the reactor, the asymptotic constant of the relative correlated variance, the reactivity of the reactor for the states in which the decay constant of the prompt neutrons is measured, and the efficiency of the neutron detector. The measurements that can be made with the professional analyzer NSA-1000 on-line with a reactor and a digital computer (Model PC-350-DZ) are also described

[en] The records of the Radiotherapy Division of the Radiology Department of Vanderbilt University Hospital were reviewed for the period 1952 to 1970. During those 19 years 45 patients with a well-documented diagnosis of Cushing's disease were treated initially by external irradiation of the pituitary. All of the patients were treated with megavoltage equipment using photons. When the results of irradiation are compared against total doses of radiation, it is evident that the control rate is unsatisfactory at doses less than 4000 rad and the maximum benefits of irradiation are evident in the 4500 to 5000 rad dose range. It is also clear that the complication rate increases as the dose exceeds 4800 rad. If the various treatment regimens of irradiation are converted to ''equivalent'' doses by the Nominal Standard Dose (NSD) or Time-Dose-Fractionation (TDF) methods, the relationship between ''dose'' and efficacy of therapy and complications is demonstrated. In order to reduce the possibility of treatment-related morbidity, the use of three or more small (4 x 4 cm) treatment portals or rotational techniques is recommended to a pituitary dose of 4600 to 5000 rad treating 5 days a week for 5 to 6 weeks

[en] We report angle resolved photoemission spectra (ARPES) from the Fermi energy (E_F) over a large area of the reciprocal space using polarized and unpolarized synchrotron radiation light, in two particular distinctive geometries of detection from a mono-domain single crystal of Bi₂Sr₂CaCu₂O_8+x (Bi-2212) optimally doped. The data display a wide-ranging level of accord with previously reported ARPES results and clarify how many apparently dissimilar Fermi surface (FS) maps emerge in ARPES, under different experimental conditions. The energy and polarization dependences of the ARPES matrix elements help disentangle primary contributions from the main FS bands to the spectrum from those arising from secondary effects. The remarkable influence of the matrix elements on the ARPES intensity allows us to unravel the principal FS bands, from those robust features associated to the incommensurate superstructure modulations, as well as provide us a reliable route for separating closely placed FS sheets in low dimensional materials