Uloga zadataka otvorenoga tipa u razvoju aktivnosti i kreativnoga mišljenja učenika

Abstract The subjects of this research work are open-ended tasks which importance can be seen in the fact that they enable different approaches to reach different possible solutions that are appropriate to levels of student understanding. The basic importance of the tasks of this kind lies in the fact that they can be used to learn different strategies, deepen students\u27 mathematical knowledge and develop their creative mathematical thinking. The approach to solving of open-ended tasks is a step closer to connecting of students\u27 mathematical literacy and real-life situations. This paper aims to investigate the effects of open-ended tasks in teaching mathematics on the outcome of learning mathematics and the opinion of students and teachers about it. By comparing the students’ answers it was concluded that there is no statistically significant difference in test results of experimental group solving  open-ended tasks in relation to control group that solved closed tasks. This is justified by greater experience of students gained in solving closed tasks. By analysing the activity in task solving it was concluded that there is statistically significant difference of experimental group in relation to control group. Key words: class activity; communication; levels of student knowledge; open-ended and closed tasks.U fokusu ovog istraživanja su zadatci otvorenog tipa. Njihova je važnost vidljiva u tome što omogućuju različite postupke dolaska do višestrukih mogućih rješenja primjerenih za različite razine razumijevanja učenika. Osnovni smisao tih zadataka je mogućnost njihovog korištenja za učenje različitih strategija, produbljivanje učeničkog znanja matematike i razvijanje kreativnoga matematičkog mišljenja. Pristup rješavanju zadataka otvorenoga tipa predstavlja korak bliže povezivanju matematičke pismenosti učenika i stvarnih životnih situacija. Cilj je ovoga rada istražiti učinke zadataka otvorenog tipa u poučavanju matematike na ishode učenja matematike i mišljenje učenika i učitelja o njima. Usporedba učeničkih odgovora nije pokazala statistički značajnu razliku između rezultata testa eksperimentalne skupine, koja je rješavala zadatke otvorenog tipa, i kontrolne skupine, u kojoj su učenici rješavali zadatke zatvorenog tipa. Veće iskustvo koje su učenici stekli rješavajući zadatke zatvorenog tipa objašnjava navedeni rezultat. Analiza aktivnosti u rješavanju zadataka ukazuje na statistički značajnu razliku između eksperimentalne i kontrolne skupine

Can a presepsin (SCD14-ST) obtained from tracheal aspirate be a biomarker for early-onset neonatal sepsis

© 2020, University of Kragujevac, Faculty of Science. All rights reserved. In absence of clear clinical signs and clear definition, neonatal sepsis is still one of the major cause of morbidity and mortality. Most researchs in past time was directional on finding new biomarkers with greater sensitivity and specific-ity in detection of neonatal sepsis. The aim of our study was to investigate if presepsin obtained from tracheal asprate in intubated newborns, can be a novel biomarker of systemic bacterial infection. Our ‘’case control’’ study included 60 newborns, 11 with suspected neonatal sepsis. Tracheal aspirate for examination was taken in the usual toilets, in asep-tic conditions, by lavage with 2 ml of 0.9% NaCl in Mucus suction set. In the same day were mesured presepsin (blood), CRP, PCT, leukocytes and neutrophyls, as well as blood cul-ture. Our research showed higher levels for PCT and prese-psin (blood) in septic newborns, as well as in newborns with clinical signs of SIRS. Presepsin obtained from a tracheal aspirate had high score for septic newborns. As the coefficients of simple linear correlation showed, there was quantitative agreement between presepsin (blood) with presepsin (trache-al aspirate)-increase in the value of one leads to an increase in other. In conjunction with an already validated markers of infection, presepsin obtained from tracheal aspirate cam be turned on in diagnostic procedures

TWENTY YEARS OF THE FACTA UNIVERSITATIS, SERIES PHYSICAL EDUCATION AND SPORT: THE HISTORICAL ASPECTS OF RESEARCH METHODOLOGY IN SPORT AND PHYSICAL EDUCATION

The aim of this paper was to use the analysis of all the articles published in the journal Facta Universitatis – series: Physical Education and Sport since it was first published  in 1994, up to 2013 to gain insight into the research methodology used in sport and physical education. For the purpose of this analysis, the authors classified the articles based on various criteria which are considered good methodological indicators (type of article, research design, field of study, characteristics of the sample of participants, measuring instruments, data processing methods). By monitoring the individual methodological characteristics of the research done in sport and physical education, we were able to explain the development of research methodology in this field, as well as the trends of research methodology both in theory and practice, including whether there is a possible imbalance between the number of published articles in various fields of study, what the relationship between the longitudinal and transversal studies is and so on. By gaining insight into the improvements made in the applied testing procedures, study design, choice of participants and methods of statistical data processing in the articles published in the journal Facta Universitatis - series: Physical Education and Sport, we can conclude that our science over the past twenty years has achieved a significant improvement in terms of research methodology

Nanoindentation of nickel manganite ceramics obtained by complex polimerization method

Nickel manganite is very interesting NTC material due to its outstanding properties and wide field of applications mainly in microelectronics and optoelectronics and lately in the mobile phone industry. In this work, chemical synthesis of this material was performed by complex polymerization method (CPM). The presence of pure nickel manganite phase was confirmed by X-ray analysis. The obtained fine nanoscaled powders were uniaxially pressed and sintered at different temperatures: 1000 C -1200C for 2h. Microstructure development during sintering was observed by scanning electron microscope (SEM). Indentation experiments were carried out using a three sided pyramidal (Berkovich) diamond tip. Young’s modulus of elasticity at various indentation depths and hardness of NTC ceramics were calculated. It was found that the highest hardness and elastic modulus exhibit the ceramics sintered at highest temperature

Wandering spleen-a possible cause of adrenal ”mass“-case report

Wandering spleen is a very rare clinical condition character-ized by spleen absence in the normal anatomical location in the upper left quadrant of the abdomen and its presence at another location in the abdomen or pelvis. The ectopic spleen is extremely rare in children, where its increased mobility is the result of a congenital disturbance of the fixation for the anterior wall due to the absence or weakness of the supporting ligaments. Wandering spleen is usually asymptomatic, but its torsion is possible, as well as infarction or rupture which demand an urgent diagnosis and surgical treatment. The diagnosis of wandering spleen can easily be overlooked due to low incidence and insufficient clinical experience, which multiplies patient's risk from life-threatening conditions. We present a case of wandering spleen in an 11-year-old girl with acute abdominal pain, which after ultrasound examination raised suspicion on the right adrenal gland tumor. Additional diagnostics verified an ectopic spleen in the right adrenal box, after which the recommended preventive splenopexy was seriously considered. Due to the fixation of the vital spleen in the new position, but also the negative attitude of the parents towards the surgical intervention, clinical monitoring was selected, with exclusion of intense physical activity that carries the risk of traumatization of the spleen. As the girl has been in good health for over 3 years and without symptoms, we consider that the selection of conservative access although difficult, was correct. We hope that our experience in treating wandering spleen in girls will increase the number of valid facts about this rare condition

Detection and alterations of acetylcarnitine (AC) in human liver by 1H MRS at 3T after supplementation with L-carnitine

Purpose: Acetylcarnitine can be assessed in vivo using proton MRS (1H-MRS) with long TEs and this has been previously applied successfully in muscle. The aim of this study was to evaluate a 1H-MRS technique for liver acetylcarnitine quantification in healthy humans before and after L-carnitine supplementation. Method: Baseline acetylcarnitine levels were quantified using a STEAM sequence with prolonged TE in 15 healthy adults. Using STEAM with four different TEs was evaluated in phantoms. To assess reproducibility of the measurements, five of the participants had repeated 1H-MRS without receiving L-carnitine supplementation. To determine if liver acetylcarnitine could be changed after L-carnitine supplementation, acetylcarnitine was quantified 2 h after intravenous L-carnitine supplementation (50 mg/kg body weight) in the other 10 participants. Hepatic lipids were also quantified from the 1H-MRS spectra. Results: There was good separation between the acetylcarnitine and fat in the phantoms using TE = 100 ms. Hepatic acetylcarnitine levels were reproducible (coefficient of reproducibility = 0.049%) and there was a significant (p Conclusion: Our results demonstrate that our 1H-MRS technique could be used to measure acetylcarnitine in the liver and detect changes following intravenous supplementation in healthy adults despite the presence of lipids. Our techniques should be explored further in the study of fatty liver disease, where acetylcarnitine is suggested to be altered due to hepatic inflexibilities

Simvastatin is effective in killing the radioresistant breast carcinoma cells

Background. Statins, small molecular 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, are widely used to lower cholesterol levels in lipid-metabolism disorders. Recent preclinical and clinical studies have shown that statins exert beneficial effects in the management of breast cancer by increasing recurrence free survival. Unfortunately, the underlying mechanisms remain elusive. Materials and methods. Simvastatin, one of the most widely prescribed lipophilic statins was utilized to investigate potential radiosensitizing effects and an impact on cell survival and migration in radioresistant breast cancer cell lines. Results. Compared to parental cell counterparts, radioresistant MDA-MB-231-RR, T47D-RR andAu565-RR cells were characterized by upregulation of 3-hydroxy-3-methylglutharyl-coenzyme A reductase (HMGCR) expression accom-panied by epithelial-to-mesenchymal transition (EMT) activation. Radioresistant breast cancer cells can be killed by simvastatin via mobilizing of a variety of pathways involved in apoptosis and autophagy. In the presence of simvasta-tin migratory abilities and vimentin expression is diminished while E-cadherin expression is increased. Conclusions. The present study suggests that simvastatin may effectively eradicate radioresistant breast carcinoma cells and diminish their mesenchymal phenotypes

ANTIFUNGAL ACTIVITY OF ESSENTIAL OILS ON ASPERGILLUS FLAVUS ORIGINATING FROM MAIZE KERNELS

The application of pesticides is an actual plant protection measure in agriculture that can have adverse effects on people’s health and environments. A great attention is paid to the biological fungicides. Performed studies indicate satisfactory results of activities of essential oils, which furthermore point out to possibilities of their inclusion in crop protection programs. The aim of this study was to determine antifungal, contact activity of essential oils of thyme (Thymus vulgaris L.) and oregano (Origanum vulgare L.) on toxigenic fungal species Aspergillus flavus causing maize kernel rot. The sterile filter paper was placed in the inner lead of Petri dish. Two, four, six, eight and 10 μl of essential oils were pipetted on the paper, and then pure A. flavus cultures were subcultured on PDA. After seven days in the dark at 25°C, the degree of inhibition was determined by measuring the fungal growth and their comparison to the control. The fungus, without addition of essential oils, was used as the control. The strongest antifungal activity was expressed by thyme essential oil, which already at the amount of 2 μl completely inhibited the mycelium growth. The identical effect was achieved with the amount of 4 μl. The greater amount of essential oil the more progressive growth of the fungal colony (6 μl – 3 mm; 8 μl – 9 mm). However, the mycelium growth at the amount of 10 μl of essential oil was only 1 mm. The similar results were gained with oregano essential oil (2 μl – 3 mm; 4 μl – 7 mm; 6 μl – 9 mm; 8 μl – 9 mm; 10 – 6 mm). The fungal growth of control was 30 mm. The obtained results indicate the significant potential of the application of thyme and oregano essential oils as possible natural and environmentally friendly means for the protection of maize against A. flavu