Ehrenfest Dynamics and Frictionless Cooling Methods

Recently introduced methods which result in shortcuts to adiabaticity, particularly in the context of frictionless cooling, are rederived and discussed in the framework of an approach based on Ehrenfest dynamics. This construction provides physical insights into the emergence of the Ermakov equation, the choice of its boundary conditions, and the use of minimum uncertainty states as indicators of the efficiency of the procedure. Additionally, it facilitates the extension of frictionless cooling to more general situations of physical relevance, such as optical dipole trapping schemes. In this context, we discuss frictionless cooling in the short-time limit, a complementary case to the one considered in the literature, making explicit the limitations intrinsic to the technique when the full three-dimensional case is analyzed.Comment: 9 pages, 4 figures, v2: To appear in Physical Review A. (some minor typos corrected and some references added

A Yoga Intervention for Stress Management of Young Athletes During Covid-19 Lockdown

This research aimed to check the effectiveness of a specially designed yogic package suitable for athletes who were in fear due to the covid-19 lockdown to test its effectiveness in bringing back their mental power. Yoga is not a new science. Centuries back, the importance of physical and psychological health and the impact of yoga has been explained in Thirumandiram by Yoga Maharishi Thirumoolar. Psychological resilience is necessary to enhance athletic performance and foster valuable life skills. Through positive adaptation to adversity and stressors in competitive performance, athletes can cultivate their ability to respond to negative stimuli, ultimately evolving personal growth effectively. For young athletes, the development of resilience is particularly crucial. Due to confinement and social isolation regulations, young athletes face distinct challenges in sport, including future fear, physical toughness, body image issues, emotional maturity, increased mental distress, and internalization of emotions during a covid lockdown. The aim of this research is to test if yoga could build resilience and discuss the implications and applications relevant to young athletes. 30 young athletes between 19 - 21 years accepted to participate in the research were accommodated. The pretest was conducted on the selected variables and selected subjects were assigned into two groups of 15 subjects each. The Experimental Group (YG) underwent yoga training and the control group (CG) did not undergo any specific training for 3 weeks (6 days a week for 2 sessions a day).  After 3 weeks of training, a post-test was conducted on resilience (self-determination, physical toughness and Emotion control & Maturity) for both groups. To find out if any significant difference exists between pre and post-training, a t-ratio was applied.  The result depicts that yoga is the best tool to work on resilience in such unprecedented tough times, securing current physical and mental health, enhancing sports performance, and helping young athletes stay navigated to life's goals

Serological diagnosis of pulmonary aspergillosis

Methods for the preparation of antigens from clinically isolated cultures of Aspergillus were standardized. Sera from 25 suspected cases of pulmonary aspergillosis were tested against antigens prepared by us, from 4 strains of A. fumigatus and one strain of A. flavus, using the Ouchterlony double diffusion and immunoelectrophoretic techniques. Of the 25 sera tested, 18 reacted positively with antigens of A.fumigatus, one with A.flavus and 2 with both these species. Antigens of two non-pathogenic Aspergilli included in the study failed to react with any of the sera. Our antigen preparations gave more numerous as well as sharper precipitin lines than the commercial Bencard antigens which were used for comparison. Moreover, mycelial antigens from 48 to 96 h old cultures revealed precipitin lines comparable to that of the routine, 4 week old culture filtrate antigens, thus suggesting that the incubation period for obtaining antigens could be cut down considerably

Bicriteria Network Design Problems

We study a general class of bicriteria network design problems. A generic problem in this class is as follows: Given an undirected graph and two minimization objectives (under different cost functions), with a budget specified on the first, find a <subgraph \from a given subgraph-class that minimizes the second objective subject to the budget on the first. We consider three different criteria - the total edge cost, the diameter and the maximum degree of the network. Here, we present the first polynomial-time approximation algorithms for a large class of bicriteria network design problems for the above mentioned criteria. The following general types of results are presented. First, we develop a framework for bicriteria problems and their approximations. Second, when the two criteria are the same %(note that the cost functions continue to be different) we present a ``black box'' parametric search technique. This black box takes in as input an (approximation) algorithm for the unicriterion situation and generates an approximation algorithm for the bicriteria case with only a constant factor loss in the performance guarantee. Third, when the two criteria are the diameter and the total edge costs we use a cluster-based approach to devise a approximation algorithms --- the solutions output violate both the criteria by a logarithmic factor. Finally, for the class of treewidth-bounded graphs, we provide pseudopolynomial-time algorithms for a number of bicriteria problems using dynamic programming. We show how these pseudopolynomial-time algorithms can be converted to fully polynomial-time approximation schemes using a scaling technique.Comment: 24 pages 1 figur

Wireless strain sensing system for assessing condition of civil infrastructure facilities

Bežični senzori i senzorske mreže postaju zamjena za tradicionalne sustave za praćenje ponašanja konstrukcija. Njihova je prednost u nižoj cijeni ugradnje jer nema potrebe za polaganjem dugih kabela između senzora i sustava za prikupljanje podataka. U radu se opisuju istraživanja provedena u svrhu ocjenjivanja učinkovitosti bežičnih senzora za mjerenje relativnih deformacija. Dan je primjer primjene bežičnog senzorskog sustava pri mjerenju ponašanja konstrukcije željezničkog mosta te je napravljena usporedba s primjenom klasičnih sustava.Wireless sensors and sensor networks are emerging as substitutes for traditional structural monitoring systems. Their benefit lies in a lower cost of installation because extensive wiring is no longer required between sensors and the data acquisition system. Studies carried out to evaluate performance of wireless strain measurement units are described in this paper. An example is given of a wireless system used for measuring behaviour of a railway bridge, and comparison with traditional systems is made