Negative-Energy Spinors and the Fock Space of Lattice Fermions at Finite Chemical Potential

Recently it was suggested that the problem of species doubling with Kogut-Susskind lattice fermions entails, at finite chemical potential, a confusion of particles with antiparticles. What happens instead is that the familiar correspondence of positive-energy spinors to particles, and of negative-energy spinors to antiparticles, ceases to hold for the Kogut-Susskind time derivative. To show this we highlight the role of the spinorial ``energy'' in the Osterwalder-Schrader reconstruction of the Fock space of non-interacting lattice fermions at zero temperature and nonzero chemical potential. We consider Kogut-Susskind fermions and, for comparison, fermions with an asymmetric one-step time derivative.Comment: 14p

Geometrical Research of Erosive Processes Using the Method of Triplet Quasiconvergent Phototopography

Запропоновано досліджувати ерозію ґрунту із застосуванням методу триплетної квазіконвергентної фототопографії. Розроблено методику організації польового геостаціонару, обґрунтувано поетапність польових і камеральних робіт. Дано теорію методу визначення елементів внутрішнього та зовнішнього орієнтування квазі- й реальних знімків. Виконано практичну апробацію методу та емпірично отримано його точність.There is proposed to study soil erosion using the method of triplet quasiconvergent phototopography. The method of organization of field geo permanent establishment was elaborated, the grounds of phasing field and laboratory works were accomplished. There was given a theory of method for inner and outer orientation of quasi- and real photographs determination. There was done practical approbation of the method and its precision was received empirical

USE OF WOUND PROTECTOR FOR PREVENTION OF SURGICAL SITE INFECTION IN LAPAROSCOPIC CHOLECYSTECTOMY

The work is based on the experience of 759 cholecystectomies performed in 2015-2018. Patients with a 3-4 grades of microbial contamination of wounds were divided into two groups: the first, with removal of the gallbladder traditionally with specimen retrieval container and the second, where proposed method of combined use of container and wound protector was used − 19 patients.Surgical site infection in laparoscopic cholecystectomy was detected in 5.40% (41 patients out of 759). During surgical interventions related to the second grade of microbial contamination (clean-contaminated), the frequency of SSI was 2.50%, to the third grade (contaminated) − 11.76%, and to the fourth grade (dirty) − 34.92%. Using the proposed method for the simultaneous use of the retrieval container and the double-ring wound protector in the second and third grades of wounds in LC allowed to reduce the frequency of SSI from 37.70% to 5.26%.The work is based on the experience of 759 cholecystectomies performed in 2015-2018. Patients with a 3-4 grades of microbial contamination of wounds were divided into two groups: the first, with removal of the gallbladder traditionally with specimen retrieval container and the second, where proposed method of combined use of container and wound protector was used − 19 patients.Surgical site infection in laparoscopic cholecystectomy was detected in 5.40% (41 patients out of 759). During surgical interventions related to the second grade of microbial contamination (clean-contaminated), the frequency of SSI was 2.50%, to the third grade (contaminated) − 11.76%, and to the fourth grade (dirty) − 34.92%. Using the proposed method for the simultaneous use of the retrieval container and the double-ring wound protector in the second and third grades of wounds in LC allowed to reduce the frequency of SSI from 37.70% to 5.26%

Vanishing of Gravitational Particle Production in the Formation of Cosmic Strings

We consider the gravitationally induced particle production from the quantum vacuum which is defined by a free, massless and minimally coupled scalar field during the formation of a gauge cosmic string. Previous discussions of this topic estimate the power output per unit length along the string to be of the order of $10^{68}$ ergs/sec/cm in the s-channel. We find that this production may be completely suppressed. A similar result is also expected to hold for the number of produced photons.Comment: 10 pages, Plain LaTex. Minor improvements. To appear in PR

Using level-2 fuzzy sets to combine uncertainty and imprecision in fuzzy regions

In many applications, spatial data need to be considered but are prone to uncertainty or imprecision. A fuzzy region - a fuzzy set over a two dimensional domain - allows the representation of such imperfect spatial data. In the original model, points of the fuzzy region where treated independently, making it impossible to model regions where groups of points should be considered as one basic element or subregion. A first extension overcame this, but required points within a group to have the same membership grade. In this contribution, we will extend this further, allowing a fuzzy region to contain subregions in which not all points have the same membership grades. The concept can be used as an underlying model in spatial applications, e.g. websites showing maps and requiring representation of imprecise features or websites with routing functions needing to handle concepts as walking distance or closeby

The Savvidy ``ferromagnetic vacuum'' in three-dimensional lattice gauge theory

The vacuum effective potential of three-dimensional SU(2) lattice gauge theory in an applied color-magnetic field is computed over a wide range of field strengths. The background field is induced by an external current, as in continuum field theory. Scaling and finite volume effects are analyzed systematically. The first evidence from lattice simulations is obtained of the existence of a nontrivial minimum in the effective potential. This supports a ``ferromagnetic'' picture of gluon condensation, proposed by Savvidy on the basis of a one-loop calculation in (3+1)-dimensional QCD.Comment: 9pp (REVTEX manuscript). Postscript figures appende

Maximum gradient embeddings and monotone clustering

Let (X,d_X) be an n-point metric space. We show that there exists a distribution D over non-contractive embeddings into trees f:X-->T such that for every x in X, the expectation with respect to D of the maximum over y in X of the ratio d_T(f(x),f(y)) / d_X(x,y) is at most C (log n)^2, where C is a universal constant. Conversely we show that the above quadratic dependence on log n cannot be improved in general. Such embeddings, which we call maximum gradient embeddings, yield a framework for the design of approximation algorithms for a wide range of clustering problems with monotone costs, including fault-tolerant versions of k-median and facility location.Comment: 25 pages, 2 figures. Final version, minor revision of the previous one. To appear in "Combinatorica

СОВРЕМЕННЫЕ ВЗГЛЯДЫ НА КОНВЕРСИЮ ПРИ ЛАПАРОСКОПИЧЕСКОЙ ХОЛЕЦИСТЭКТОМИИ

СОВРЕМЕННЫЕ ВЗГЛЯДЫ НА КОНВЕРСИЮ ПРИ ЛАПАРОСКОПИЧЕСКОЙ ХОЛЕЦИСТЭКТОМИ