Technical efficiency of Serbian dairy processing industry

Serbian dairy processing sector is passing through significant structural changes in last couple decades. Concentration, vertical coordination and integration become a main characteristics. The main goal of the paper is to explore technical efficiency of 91 Serbian dairy processors in sample by non-parametric method Data envelopment analysis. Data were collected from financial reports of dairy companies in 2015. All dairy companies were divided in 4 groups: micro, small, middle and big. The empirical results indicate that 16.5% of companies were technically efficient. This study shows that efficient companies exist across all size groups, and while small companies suffer from input inefficiency and insufficient size of business, the bigger companies are over invested

Efficiency of wheat production in Republic of Serbia

Wheat is one of the most important cereal and it is considered primarily as a source of energy (carbohydrate), in human diet. In Serbia, the most farms producing crops, where wheat is one of the most important crop. The paper investigates differences in efficiency of wheat production among Serbian farms with objective to identify the most efficient farms and possibilities for further improvement. Data for 2015/2016 production year are gathered through questionnaire during farms visit. In the paper non-parametric models of Data Envelopment Analysis (DEA) was used to identify differences in efficiency of wheat production among farms. The results reveal importance of farm size, size of plots and investments in the new machinery

Piezoresistant probe for measurement of velocity in one-dimensional incompressible flow

Radeći na problemu kalibracije sondi sa zagrejanim vlaknima u okviru rada [3], javila se potreba za sondom kojom se može meriti trenutna brzina u jednodimenzijskom vazdušnom mlazu. Ubrzo potom na Mašinskom fakultetu u Beogradu je razrađena ideja o prvoj domaćoj piezorezistivnoj sondi kojom se meri trenutni diferencijalni pritisak. Sonda je realizovana u saradnji sa IHTM, Centrom za mikroelektronske tehnologije i monokristale. Probna ispitivanja su pokazala da se sonda može uspešno koristiti za merenje trenutne brzine jednodimenzijskog nestišljivog strujanja. U tom smislu je posle prvenac sonde napravljeno još nekoliko sličnih sondi. U radu su dati osnovni elementi tehnološkog postupka za dobijanje senzora pritiska. Pored detaljnog opisa senzorskog čipa ovde su prikazani i drugi elementi sonde JR-p. Pre svakog merenja sondom ona mora da se baždari. Sonda JR-p se baždari statički i u kvazistacionarnom vazdušnom mlazu. Ovde su prikazani rezultati jednog takvog baždarenja.Working on the problem of calibration of hot wire probes within (3), we came to the need to have a probe for measuring the instantaneous velocity in a one-dimensional air jet. Soon after the idea concerned with the first domestic piezoresistant probe by means of which the instantaneous differential pressure can be measured was developed on the Faculty of Mechanical Engineering. The probe was realized in the collaboration with IHTM, the Center for microelectronic technology and monocrystals. First tests with the probe showed that it could be successfully used for measuring the instantaneous velocity in one-dimensional incompressible flows. In that sense, some more similar probes were produced after the pioneering one. In this paper the basic elements of the technological procedure for the production of the pressure sensor are given. In addition to a detailed description of the sensor chip we show here some other elements of the probe JR-p also. Before any use the probe must be calibrated. The probe JR-p is calibrated statically in a quasi-steady air jet. The results of such a calibration are presented here

Piezoresistant probe for measurement of velocity in one-dimensional incompressible flow

Radeći na problemu kalibracije sondi sa zagrejanim vlaknima u okviru rada [3], javila se potreba za sondom kojom se može meriti trenutna brzina u jednodimenzijskom vazdušnom mlazu. Ubrzo potom na Mašinskom fakultetu u Beogradu je razrađena ideja o prvoj domaćoj piezorezistivnoj sondi kojom se meri trenutni diferencijalni pritisak. Sonda je realizovana u saradnji sa IHTM, Centrom za mikroelektronske tehnologije i monokristale. Probna ispitivanja su pokazala da se sonda može uspešno koristiti za merenje trenutne brzine jednodimenzijskog nestišljivog strujanja. U tom smislu je posle prvenac sonde napravljeno još nekoliko sličnih sondi. U radu su dati osnovni elementi tehnološkog postupka za dobijanje senzora pritiska. Pored detaljnog opisa senzorskog čipa ovde su prikazani i drugi elementi sonde JR-p. Pre svakog merenja sondom ona mora da se baždari. Sonda JR-p se baždari statički i u kvazistacionarnom vazdušnom mlazu. Ovde su prikazani rezultati jednog takvog baždarenja.Working on the problem of calibration of hot wire probes within (3), we came to the need to have a probe for measuring the instantaneous velocity in a one-dimensional air jet. Soon after the idea concerned with the first domestic piezoresistant probe by means of which the instantaneous differential pressure can be measured was developed on the Faculty of Mechanical Engineering. The probe was realized in the collaboration with IHTM, the Center for microelectronic technology and monocrystals. First tests with the probe showed that it could be successfully used for measuring the instantaneous velocity in one-dimensional incompressible flows. In that sense, some more similar probes were produced after the pioneering one. In this paper the basic elements of the technological procedure for the production of the pressure sensor are given. In addition to a detailed description of the sensor chip we show here some other elements of the probe JR-p also. Before any use the probe must be calibrated. The probe JR-p is calibrated statically in a quasi-steady air jet. The results of such a calibration are presented here

Evaluation of absolute volume of human fetal kidney's cortex and medulla during gestation

Background. Human fetal kidney is quite different from the mature kidney, both macroscopically and hystologically. Lobulated surface of the human fetal kidney reflects its inner organization. Aim. To determine the fetal kidneys' volume according to the gestational age, to establish periods of their maximal and minimal growth and to compare these values for various gestational ages. Methods. Forty five human fetal kidneys aged from IV to X lunar months were analyzed. Kidneys were divided into nine groups according to their gestational age. The volumes of cortex and medulla were determined using stereological methods. The results were statistically analyzed and the periods of significant growth of these structures were marked. Results. Fetal kidney's cortex and medulla grew continually with a very high coefficient of linear correlation with crown-rump length. The cortex/medulla ratio was minimal in the first half of V lunar month, when medulla grew most rapidly and it was maximal immediately before birth, when cortex achieved its maximum. Conclusion. This study was an effort to provide some parameters which would help in the future investigations of the development of human fetal kidney

Stabilnost morfoloških osobina semena kukuruza u različitim proizvodnim uslovima

The analyses were performed with the hybrid seeds of four hybrid combinations derived at the Maize Research Institute, Zemun Polje and produced in three locations. Under laboratory conditions, the following seed traits were analysed in the working sample of 10x100 seeds: seed test weight and shelling percentage, which was determined as the seed weight to ear weight ratio. In the three-year study, the greatest (352.71 g), i.e. smallest (280.09 g) test weight was recorded in the hybrids ZP 434 and ZP 704, respectively. The highest shelling percentage of 60.53 % was determined in the hybrid ZP 704, while the lowest one (48.20 %) was recorded the hybrid ZP 434. Obtained results point out that both traits in all four hybrids are highly expressed under all observed agro-ecological conditions and that effects of factors on the seed weight and the shelling percentage are great.U ovim istraživanja posmatrane su masa 1000 semena i randman semena, u odnosu na genotipsku kombinaciju i agroekološke uslove proizvodnje semena. Analize su rađene na hibridnom semenu četiri komercijalne hibridne kombinacije Instituta za kukuruz 'Zemun Polje', proizvedene na tri lokaliteta. U laboratorijskim uslovima, na radnom uzorku od 10x100 semena, izvršena su ispitivanja apsolutne mase semena, randman semena utvrđen je kao procentualni odnos mase semena i klipa. U trogodišnjem istraživanju najveća izmerena masa 1000 semena je kod hibrida ZP 434 (352,71 g) dok je ZP 704 hibrid sa najmanjom postignutom masom(280,09 g). Randman semena najveći je kod ZP 704 (60,53%), najmanji 48,20% kod ZP 434. Lokalitet sa najvećim variranjem mase bio je Turija (41,58%), a druga osobina najviše varijabilnosti u toku istraživanja bila je na lokalitetu Vrbas (28,13%). Eksperimentalni podaci obrađeni su na srednju vrednost i ukupnu varijabilnost (x i C.V.) za obe osobine semena i svaku varijantu istraživanja. Dvofaktorijalnom analizom varijanse utvrđen je uticaj faktora (hibrid i lokacija), kao i njihova interakcija na ispitivane osobine semena. Dobijeni rezultati pokazali su da sva četiri hibrida imaju visok nivo ispoljavanja obe osobine u svim posmatranim agroekološkim uslovima, kao i visok uticaj faktora (hibrid i lokacija) na masu semena i randman semena

The sum of temperature units in different pheno-phases of development of seed maize regarding the production year

The aim of this study was to determine variability of temperature sums for the occurrence of pheno-phases of silking, tasselling and pollination of seed maize. Nine maize inbred lines were tested in two production years. Compatibility and overlapping of silking, tasselling and pollination of parental components in a seed crop are important for achieving high yields. According to obtained data, the degree of accumulation of temperature sums was higher in the first year than in the second production year for all stages, except for the beginning of tasselling. The differences were statistically significant: the greatest and smallest differences were obtained for tasselling (t2 - 70.9oC) and the beginning of silking (s1- 20.86oC), respectively. The effect of genotypes on differences in temperature sums was the greatest for all pheno-phases, p<0.005. The effect of the production year on the number of temperature units necessary for silking and pollination was also high, but there was no high statistical effect on the beginning of tasselling. Since maize is a plant species that is grown in different regions, maize growing practices should be adjusted to the main aim of maize production, to achieving high and stable yields

Molekularnobiološke osobine oralnih skvamocelularnih karcinoma

Oral squamous cell carcinomas (OSCCs) are associated with poor prognosis, and despite advances in therapy approaches, no major improvement in survival has been achieved in the recent years. Efforts are now directed toward finding new biological markers that could predict tumor behavior more accurately. OSCCs, as the majority of malignant tumors, arise from progressive accumulation of genetic and epigenetic lesions, transforming normal cells into malignant. In this paper, an analysis of current studies directed to understanding the underlying mechanisms of OSCC pathogenesis was presented. The emphasis was put on mutational analysis of cancer genes, as well as on the role of viral infections and methylation processes in OSCC. Finally, an overview of studies that tried to determine the possibility for developing OSCC was given.Oralne skvamocelularne karcinome (OSCK) odlikuje uglavnom loša prognoza i, uprkos pomacima u terapijskim postupcima, poslednjih godina nije ostvaren napredak u preživljavanju osoba s ovim tumorom. Velike nade se polažu u molekularnu medicinu i pronalaženje novih bioloških markera pomoću kojih bi preciznije nego što to dopuštaju klinički i histopatološki parametri moglo da se predvidi ponašanje tumora. OSCK, kao i većina drugih malignih oboljenja, rezultat su postupne akumulacije raznovrsnih genetičkih i epigenetičkih promena u ćelijama, koje od normalnih postaju neoplastične. U ovom radu dat je presek nekih od pravaca istraživanja na polju molekularne biologije oralnih karcinoma, s osvrtom na studije koje se bave ispitivanjem somatskih mutacija u kancerskim genima, učešćem onkogenih virusa u patogenezi i značaju procesa metilacije za OSCK. Takođe su pomenute studije posvećene utvrđivanju eventualnog postojanja predispozicije za razvoj OSCK

CHANGE OF ECG PARAMETERS DEPENDING ON THE LOAD LEVEL IN ATHLETES

The influence of physical training on bodies of athletes leads to changes that can be characterized as morphological, functional, electrophysiological and psychological. Dynamic exercise, such as running, swimming and riding a bicycle, leads to volume load of heart. Static exercise (gymnastics, weightlifting, wrestling) leads to the development of relatively large muscle force, with or without changes in muscle length and movement of the joint. Given the frequent number of sudden cardiac death cases in sport, it is important to distinguish between changes of the heart that occur as a result of adaptation to physical activity and changes due to some pathological conditions. The aim of this paper is to present the latest information on changes in ECG parameters depending on the load of athletes while performing aerobic trainings in order to better identify markers of adverse cardiovascular events, particularly sudden death in athletes. It is common to see on the ECG of athletes at rest hypertrophy of the left and right ventricle, interventricular conduction disorder, positive ST changes, and short-term tachycardia. Changes that occur in athletes are due to increased vagal tone and suppression of sympathetic nerve regulation. Many changes can be attributed to intrinsic cardiac component that is responsible for the lower frequency of athlete's heart deinnervation (with atropine or propranolol), which means that intense training influences how the autonomic regulation and the intrisic cardiac pacemaker function. It is common for athletes to have sinus bradycardia, sinus arrhythmia, first degree AV block and Mobitz I, as well as junctional rhythm, ST segment elevation, high and sharp, or biphasic T-waves, while ST depression or isolated T-wave inversion are less common. They can also have increased amplitude of P-wave and QRS complex, QRS axis rotation to the right and incomplete right branch block. Some but insufficient data tell about the presence of the third-degree AV block and atrial and ventricular ectopic beats and their predictive role for malignant rhythm disorders

Moleculobiological characteristics of oral squamous cell carcinomas

Oral squamous cell carcinomas (OSCCs) are associated with poor prognosis, and despite advances in therapy approaches, no major improvement in survival has been achieved in the recent years. Efforts are now directed toward finding new biological markers that could predict tumor behavior more accurately. OSCCs, as the majority of malignant tumors, arise from progressive accumulation of genetic and epigenetic lesions, transforming normal cells into malignant. In this paper, an analysis of current studies directed to understanding the underlying mechanisms of OSCC pathogenesis was presented. The emphasis was put on mutational analysis of cancer genes, as well as on the role of viral infections and methylation processes in OSCC. Finally, an overview of studies that tried to determine the possibility for developing OSCC was given.Oralne skvamocelularne karcinome (OSCK) odlikuje uglavnom loša prognoza i, uprkos pomacima u terapijskim postupcima, poslednjih godina nije ostvaren napredak u preživljavanju osoba s ovim tumorom. Velike nade se polažu u molekularnu medicinu i pronalaženje novih bioloških markera pomoću kojih bi preciznije nego što to dopuštaju klinički i histopatološki parametri moglo da se predvidi ponašanje tumora. OSCK, kao i većina drugih malignih oboljenja, rezultat su postupne akumulacije raznovrsnih genetičkih i epigenetičkih promena u ćelijama, koje od normalnih postaju neoplastične. U ovom radu dat je presek nekih od pravaca istraživanja na polju molekularne biologije oralnih karcinoma, s osvrtom na studije koje se bave ispitivanjem somatskih mutacija u kancerskim genima, učešćem onkogenih virusa u patogenezi i značaju procesa metilacije za OSCK. Takođe su pomenute studije posvećene utvrđivanju eventualnog postojanja predispozicije za razvoj OSCK.Projekat ministarstva br. 17507