The 63^{63}Ni(n,γ\gamma) cross section measured with DANCE

The neutron capture cross section of the s-process branch nucleus $^{63}$Ni affects the abundances of other nuclei in its region, especially $^{63}$Cu and $^{64}$Zn. In order to determine the energy dependent neutron capture cross section in the astrophysical energy region, an experiment at the Los Alamos National Laboratory has been performed using the calorimetric 4$\pi$ BaF$_2$ array DANCE. The (n,$\gamma$) cross section of $^{63}$Ni has been determined relative to the well known $^{197}$Au standard with uncertainties below 15%. Various $^{63}$Ni resonances have been identified based on the Q-value. Furthermore, the s-process sensitivity of the new values was analyzed with the new network calculation tool NETZ.Comment: 11 pages, 13 page

Reality Conditions and Ashtekar Variables: a Different Perspective

We give in this paper a modified self-dual action that leads to the $SO(3)$-ADM formalism without having to face the difficult second class constraints present in other approaches (for example if one starts from the Hilbert-Palatini action). We use the new action principle to gain some new insights into the problem of the reality conditions that must be imposed in order to get real formulations from complex general relativity. We derive also a real formulation for Lorentzian general relativity in the Ashtekar phase space by using the modified action presented in the paper.Comment: 22 pages, LATEX, Preprint CGPG-94/10-

Hidden Consequence of Active Local Lorentz Invariance

In this paper we investigate a hidden consequence of the hypothesis that Lagrangians and field equations must be invariant under active local Lorentz transformations. We show that this hypothesis implies in an equivalence between spacetime structures with several curvature and torsion possibilities.Comment: Some misprints appearing in the published version have been correcte

Anatomical classification of the shape and topography of the operated stomach

The aim of the study was to present the classification of anatomical variances of the operated stomach, based on the radiological and historical data. Different anatomical variations of the operated organ were revealed in 431 out of 2034 patients examined in years 2006-2010. Four primary groups were established: abnormal position along longitudinal (I) and horizontal axis (II), as well as abnormal shape (III) and stomach connections (IV). An additional group (V) encloses mixed forms that connect features of two or more primary groups. The first group contains the partial and total translocation of the stomach into the thoracic cavity after the partial or total esophagectomy. Depends on the applied surgical techniques used during the total esophagectomy, the stomach could be located in the front or back to the pericardial sac. An elongated and gestrectatical form often with signs of pylorostenosis is visible in patients treated by the vagotomy. The consequences of fundoplication included: lack or narrow cardiac angle, and often mild form of the stomach cascade. The most common abnormal shape of the stomach was secondary to the gastrectomy and gastric bending. The final organ shape depends on the type of applied surgical procedure that maintains physiological connection with the duodenum or un-anatomical one, mostly with the jejunal loop. In banding, the body of the stomach forms hourglass on the level of the artificial adjustable band, typically fitted for the surgical slim purpose

Getting the basics right-staging in head and neck cancer

The cornerstone of oncology literature and therefore medical practice is the ability to compare outcomes of treatment modalities for different stages of cancer

Covariance properties and regularization of conserved currents in tetrad gravity

We discuss the properties of the gravitational energy-momentum 3-form within the tetrad formulation of general relativity theory. We derive the covariance properties of the quantities describing the energy-momentum content under Lorentz transformations of the tetrad. As an application, we consider the computation of the total energy (mass) of some exact solutions of Einstein's general relativity theory which describe compact sources with asymptotically flat spacetime geometry. As it is known, depending on the choice of tetrad frame, the formal total integral for such configurations may diverge. We propose a natural regularization method which yields finite values for the total energy-momentum of the system and demonstrate how it works on a number of explicit examples.Comment: 36 pages, Revtex, no figures; small changes, published versio

Hamiltonian Poincar\'e Gauge Theory of Gravitation

We develop a Hamiltonian formalism suitable to be applied to gauge theories in the presence of Gravitation, and to Gravity itself when considered as a gauge theory. It is based on a nonlinear realization of the Poincar\'e group, taken as the local spacetime group of the gravitational gauge theory, with $SO(3)$ as the classification subgroup. The Wigner--like rotation induced by the nonlinear approach singularizes out the role of time and allows to deal with ordinary $SO(3)$ vectors. We apply the general results to the Einstein--Cartan action. We study the constraints and we obtain Einstein's classical equations in the extremely simple form of time evolution equations of the coframe. As a consequence of our approach, we identify the gauge--theoretical origin of the Ashtekar variables.Comment: 38 pages, plainTe

On the energy of homogeneous cosmologies

An energy for the homogeneous cosmological models is presented. More specifically, using an appropriate natural prescription, we find the energy within any region with any gravitational source for a large class of gravity theories--namely those with a tetrad description--for all 9 Bianchi types. Our energy is given by the value of the Hamiltonian with homogeneous boundary conditions; this value vanishes for all regions in all Bianchi class A models, and it does not vanish for any class B model. This is so not only for Einstein's general relativity but, moreover, for the whole 3-parameter class of tetrad-teleparallel theories. For the physically favored one parameter subclass, which includes the teleparallel equivalent of Einstein's theory as an important special case, the energy for all class B models is, contrary to expectation, negative.Comment: 11 pages, reformated with minor change