GUIDING ACCURACY OF THE WATT COMPLIANT COGNATE MECHANISMS

In kinematics, cognate linkages are those that ensure the same input-output relationship or coupler curve geometry, while being dimensionally dissimilar. Compliant mechanisms gain some or all of their mobility from the relative flexibility of their joints rather than from the rigid-body joints only, which is the case with classical mechanisms. In this paper the guiding accuracy of the compliant cognate Watt four-bar linkages has been presented. The compliant cognate mechanisms have been developed as the counterparts of the rigid-body Watt mechanism, where the coupler point can be guided on an approximate rectilinear path. The guiding accuracy of the "coupler" point on the path segment (minimal deviation between exact rectilinear and realized path) has been calculated for the new-designed compliant mechanisms

Design of the compound compliant Scott-Russel mechanism with non-conventional optimization of flexure hinges

Compliant mechanisms gain some or all their mobility from the relative flexibility of their joints rather than from rigid-body joints only. Compliant mechanisms can provide many benefits in the solution of design problems: they have less wear, weight, noise, and backlash than their rigid-body counterparts. They can be manufactured from one piece of material, and therefore they are suitable to be applied in micromechanics. However, nonlinearities introduced by the large deflection of elastic segments further complicate the analysis of compliant mechanisms. This paper considers the isosceles slider–crank mechanism and its compliant counterpart mechanism, being developed based on the rigid–body mechanism. The design of the compound compliant slider-crank mechanism with circular flexure hinges notch, consisting of two single compliant slider-crank mechanisms has been shown in this paper. The guiding accuracy and mobility of the newly designed compliant mechanism have been analyzed. Additionally, by using undercut notch flexure hinges, a new analysis is given, which aims to show another factor that has an impact on the operation of compliant mechanisms. This factor is represented by the position of joints and its influence is shown through improving the accuracy of the coupler point rectilinear path of the Scott-Russel mechanism. Hence, it will be described that the position of these flexure hinges and their geometry is a vital issue for performing an approximately rectilinear path. Therefore, several designs are investigated through the finite elements method (FEM) simulation

Uslovi gajenja i zdravstveno stanje teladi na malim seoskim farmama

Good rearing conditions are the key factor for health and welfare of calves. Diarrhea, respiratory and navel infections are commonly referred to as the most common health problems in calves. The aim of this study was an observation of rearing conditions and the occurrence of the most common health problems in calves on small rural farms in Danube Region of Serbia. Data were colected from 30 farms by surveying the farmers. The questionary consisted of 75 questions pertaining to the following: general information on the farm, and on calving, nutrition, weaning, housing, hygiene of space for cows and calves, on calf diseases and diseases prevention measures. According to the answers, the average number of all categories of cattle at the fams is 18 heads. Calves are separated from their mothers immediately after birth at 67% farms. They receive colostrum up to two hours after birth at 47% of the farms and immediately after birth at 20% of the farms. Average age of calves at weaning is 13 weeks. Calves begin to use hay usually between the 1 st and 2 nd week of life, and a concentrated feed in 2 nd week. They are held in different types of pens. Farmers specified diarrhea and respiratory diseases as the most common health problems in calves. Rearing conditions at the farms often do not meet the recommendations and the breeders do not implement all of the necessary preventive measures. Corrections in this regard could contribute to better health of calves.Dobri uslovi gajenja su ključni faktor za očuvanje zdravlja i dobrobit teladi. Kao najčešći zdravstveni problemi teladi obično se navode prolivi, infekcije disajnih puteva i infekcije pupka. Cilj ovog istraživanja bio je sagledavanje uslova gajenja i učestalost pojave najčešćih zdravstvenih problema kod teladi na malim seoskim farmama u Podunavskom regionu Srbije. Podaci su prikupljeni sa 30 farmi anketiranjem farmera. Anketa se sastojala od 75 pitanja koja su se odnosila na: opšte informacije o farmi, teljenje, ishranu teladi, odbijanje, smeštaj, higijenu prostora za smeštaj plotkinja i teladi, bolesti koje se javljaju kod teladi i mere preventive bolesti. Prema odgovorima, prosečan broj goveda svih kategorija na farmama je 18. Telad se na 67% farmi odmah po rođenju odvaja od majki. Dobijaju kolostrum 2 sata po rođenju na 47% farmi, a na 20% farmi odmah po rođenju. Prosečna starost teladi pri odbijanju je 13 nedelja. Telad počinje da koristi seno obično između 1. i 2. nedelje života, a koncentrat u 2. nedelji. Telad se drže u različitim tipovima bokseva. Farmeri su naveli proliv i respiratorne bolesti kao najčešće zdravstvene probleme kod teladi. Uslovi gajenja na farmama često nisu u skladu sa preporukama i odgajivači ne sprovode sve neophodne preventivne mere za sprečavanje pojave bolesti. Korekcije u ovom pogledu bi mogle doprineti boljem zdravstvenom stanju teladi

ASCORBIC ACID MODULATES SPONTANEOUS THYMOCYTE APOPTOSIS

The aim of the paper was to analyze the effect of various concentrations of ascorbic acid on spontaneous apoptosis of lymphocytes.About 58% of all thymocytes are subjected to a spontaneous apoptosis, after 24-hour cultivation in the complete medium. The number of apoptotic thymocytes was much lower in the culture with different concentrations of ascorbic acid. The most dramatic effect was detected in the culture with the highest concentration of ascorbic acid (10000 μg/ml). In this culture, the number of apoptotic thymocytes was about 32%. These results, compared with the results of spontaneous apoptosis, show that the most significant inhibition of apoptosis was detected in the culture with 10000 μg/ml of ascorbic acid. High concentration of ascorbic acid can inhibit spontaneous apoptosis of thymocytes. Such inhibition of T cell apoptosis, as the effector cells in immune system, can represent one of the major factors by which ascorbic acid influence the immune system

CHANGES IN SPEED, AGILITY AND BODY COMPOSITION OF TOP-RANKED FEMALE HANDBALL PLAYERS DURING THE PLAYING SEASON

Handball is a dynamic Olympic sport dominated by acyclic movements (sudden changes in direction, jumps, landings, contacts between the players, etc.) with speed and agility playing an important role in their successful realization. Our aim was to establish which changes occurred in the body composition, speed and agility of top-ranked female handball players during the playing season. The parameters for estimating body composition were: body mass, body mass index (BMI), the percentage of muscle and fat. The ability to achieve speed (in 5, 10 and 30m sprints) and agility (new envelope test without a ball, straight slalom run without a ball and Straight slalom run with a ball, zig-zag with and zig-zag without a ball) was estimated with the portable timing system. The differences between the initial and the final measurements were established with the Student’s t-test. The results obtained show that there were statistically significant changes and weaker results in almost all the tested variables. The only improvements were detected in the maximum speed in 30m sprint and the agility without a ball (new envelope test and slalom run without a ball). It is recommended that the training plan should be carefully devised (the activities of the high intensity load should be applied throughout the season) as well as the plan for proper sports nutrition (body mass should be reduced with simultaneous increase in the muscular mass component)

ANALYSIS OF REPORTING ON MALE AND FEMALE ATHLETES IN SERBIAN MEDIA DURING THE OLYMPIC GAMES IN LONDON 2012

The main goal of this paper was to find out more about how and to what extent the local media reported on sporting events at the 2012 London Olympics and to determine the difference in reporting on male and female athletes in the local media. The subject of the research are newspaper articles about sports in electronic news editions, which influence the formation of the media image about athletes, and which can contribute to the affirmation or marginalization of women in sports. In this research for collecting data and information about athletes at the Olympic Games, three media sources were used: RTS, KURIR and POLITIKA. The data have been collected since the opening of the Olympic Games until their official closing ceremony and every day was thoroughly processed in all three media sources. The information included information on the gender of the author of the text, the number of photos in the text, the number of words in the text, the gender of the actors who are on the photos, the level of exposure of the actor's bodies in the photos, the emotions in the photos, the angle of the camera, individual and group display of athletes, active or passive on-site and out-of-court conditions. Generally speaking, the findings of this research in the media space of Serbia show that there is still an imbalance in the way men and women athletes are represented, and that in this respect, there is a need for certain changes in this issue

Gentamicin nephrotoxicity in animals: current knowledge and future perspectives

Due to high relative blood flow the kidney is prone to drug-induced damage. Aminoglycoside type antibiotic gentamicin is one of the leading cause of drug-induced nephrotoxicity. In recent years gentamicin nephrotoxicity is significantly reduced by shifting to once daily dosage as well as by eliminating known risk factors. Application of gentamicin is still related to serious side effects which are reported more often compared to other antibiotics. Because gentamicin is still heavily used and is highly efficient in treating infections, it is important to find mechanisms to reduce its nephrotoxicity. This aim can only be achieved through better understanding of kidney metabolism of gentamicin. This problem has been extensively researched in the last 20 years. The experimental results have provided evidence for almost complete understanding of mechanisms responsible for gentamicin nephrotoxicity. We now have well described morphological, biochemical and functional changes in kidney due to gentamicin application. During the years, this model has become so popular that now it is used as an experimental model for nephrotoxicity per se. This situation can mislead an ordinary reader of scientific literature that we know everything about it and there is nothing new to discover here. But quite opposite is true. The precise and complete mechanism of gentamicin nephrotoxicity is still point of speculation and an unfinished story. With emerge of new and versatile technics in biomedicine we have an opportunity to reexamine old beliefs and discover new facts. This review focuses on current knowledge in this area and gives some future perspectives

SPORTS PERFORMANCE AS A MODERATOR OF THE RELATIONSHIP BETWEEN COPING STRATEGY AND EMOTIONAL INTELLIGENCE

The sample consisted of 171 elite and 169 non-elite athletes. linear regression analysis was used to test the prognostic role of emotional competence on stress coping strategies, and hierarchical regression analysis was used to test the moderating role of performance in the relationship between emotional competence and coping strategies. The result shows that EI is related to task-oriented strategies and completely unrelated to emotion-oriented strategies. Sport performance moderates the relationship between managing and regulating emotions and using avoidant coping strategies, in a way that non-elite athletes with higher scores on this EI subfactor are more likely to use distraction-oriented coping. Key words: emotional intelligence, coping, moderation, elite and non-elite athletes</p

Effect of breed of performance tested boars on ejaculate traits

The main objective of the study was to determine the influence of breed on the traits of boar ejaculate: ejaculate volume (VOL, ml), sperm concentration (CON, x106 sperm/ml), total sperm count in ejaculate (TNS, x109 spermatozoa), sperm motility in native ejaculate (MON, %), sperm motility after dilution (MOD, %) and number of doses produced (NPD). The aim was also to evaluate the correlation of the boar performance test traits: average life daily gain (g), backfat thickness measured in two locations (mm), depth of longissimus dorsi muscle (mm) and carcass meat content (%) with ejaculate traits. Total of 931 ejaculates of 36 boars during reproductive exploitation were analysed (16 Landrace boars and 20 Large White boars). The effect was assessed using the procedure of the general linear model of the statistical package SAS 9.1.3 (SAS Inst. Inc., 2002- 2003). The model for analysis included the influence of breed, season and the linear regression influence of body weight at the end of the performance test. The correlation of the traits was determined by applying the Pearson’s correlation coefficient. Most of the examined ejaculate traits (VOL, CON, MOD and NPD) varied under the influence of boar breed (p<0.01; p<0.001). Weight at the end of the test (p<0.05; p<0.01; p<0.001) affected all examined traits, except CON and TNS. A weak association was found between production performance and ejaculate traits

Synthesis, characterization and antimicrobial activity of cobalt(III) complex with (E)-4-(4-methoxyphenyl)-2-(2-(pyridin-2-ylmethylene)hydrazinyl)-1,3-selenazole

New cobalt complex with (E)-4-(4-methoxyphenyl)-2-(2-(pyridin-2-ylmethylene)hydrazinyl)-1,3-selenazole (HL) was synthesized and characterized in order to obtain biologically active compound. The complex was synthesized by the reaction of HL with cobalt(II) tetrafluoroborate. The complex was characterized by conductivity measurements, elemental analysis, FT-IR, 1H-NMR and 13C-NMR spectroscopy, while X-ray structural analysis (XRD) was used for molecular and crystal structure determination. XRD data elucidated that the complex has octahedral geometry with two ligands coordinated to cobalt(III) as tridentates, both in monoionic form, through pyridine, imine and selenazole nitrogen atoms (Fig. 1). In the outer sphere of the complex there is one tetrafluoroborate ion. The complex crystallizes as monohydrate. Antimicrobial activity of the ligand and complex was evaluated against eleven strains of bacteria and fungi. The complex showed better antibacterial than antifungal activity