Microstructure development and electrical properties of NiO doped alpha-Fe2O3

Poster presented at the 4th Serbian Congress for Microscopy, Belgrade, Serbia, 2010, October 11-12, 201

The quality of problem-oriented teaching and student achievement

U radu se analiziraju mogućnosti i načini primene problemski orijentisa­ne nastave u školskoj praksi. Cilj istraživanja bio je da se prošire dosadašnja saznanja o zastupljenosti, kvalitetu primene i o karakteristikama realizacije problemski orijentisane nastave, kao i efektu koji tako organizovana nastava ima na nivo i kvalitet učeničkog postignuća u nastavi matematike i biologije. U istraživanju je učestvovalo devedeset sedam nastavnika matematike, devedeset devet nastavnika biologije i ukupno hiljadu sto sedamnaest učenika. Korišćena je deskriptivno-analitička metoda, a podaci su prikupljeni pomoću tehnike anketiranja, skaliranja i testiranja. Rezultati istraživanja pokazuju da je problemski orijentisana nastava optimalno zastupljen način nastavnog rada u nastavi matematike, dok je u nastavi biologije zastupljena u nešto manjem obimu. Učenici čiji nastavnici često primenjuju problemski orijentisanu nastavu ostvaruju bolja postignuća u odnosu na učenike čiji nastavnici retko primenjuju ovaj način rada. U pogledu prirode problema, učenici najčešće rešavaju probleme koji sadrže veći broj informacija u tekstu, dok se ređe suočavaju sa problemima koji imaju više tačnih rešenja. Učenici uglavnom procenjuju da u toku rešavanja problema realizuju aktivnosti problemski orijentisane nastave. Ispitivanjem kvaliteta njihove realizacije ustanovljeno je da učenici ne posvećuju dovoljno pažnje početnim aktivnostima rešavanja problema, kao i vrednovanju ostvarenih rezultata. Utvrđene su pozitivne korelacije između ispitanih svojstava problema i postignuća učenika, kao i između učestalosti i kvaliteta realizacije aktivnosti problemski orijentisane nastave i postignuća učenika. Problemski orijentisana nastava uglavnom se realizuje na časovima utvrđivanja, posredstvom dijaloške metode i primenom individualnog oblika rada u nastavi matematike, a posredstvom frontalnog oblika rada u nastavi biologije.The paper analyses the possibilities and ways of implementing problem-oriented teachingin the classroom. The goal of the research was to expand the existing knowledge about the level of representation, quality of implementation, and the characteristics of the problem-oriented teaching, as well as about the effect of this form of teaching on the level and quality of student achievement in biology and mathematics. The research involved 97 mathematics teachers, 99 biology teachers, and a total of 1117 students. A descriptive-analytical method was used and the data was collected by using scaling, surveying, and testing techniques. The research results indicate that problem-oriented teaching is the most frequently used teaching approach in mathematics classroom, while it is used to a lesser extent in teaching biology. The students whose teachers frequently use problem-oriented teaching achieve better results than students who are rarely exposed to this type of teaching and learning. As far as the type of the problem is concerned, students mostly have to solve problems containing more information in the text, while the problems with several correct solutions are rarely used. Students generally realise that problem-solving process involves the activities pertaining to the problem-oriented teaching and learning. The analysis of the quality of implementation showed that students do not pay enough attention to initial activities in the problem-solving process and to the evaluation of the achieved results. Positive correlations were established between the analysed characteristics of the problems and student achievement, as well as between the frequency and quality of the problem-oriented teaching activities and student achievement. Problem-oriented teaching is mostly implemented at revision classes by using a dialogue method and individual interaction pattern in teaching mathematics, while frontal interaction pattern is mostly used in biology classes

Funkcija daktilologije u razvoju jezika kod gluvih i nagluvih učenika

Говор представља најважније средство комуникације и од његовог развоја зависи целокупан развој детета. Развој говора представља дуг и сложен процес, који има своје специфичне фазе развоја. Фактори који директно утичу на развој говора и који представљају предуслов за његов правилан развој су бројни. Један од значајних фактора у развоју говора јесте слух, те његово оштећење повлачи са собом и низ проблема који се јављају код деце са слушним оштећењима. Важност у раду са децом са слушним оштећењима, огледа се у специфичном развоју говора, који ће им касније омогућити да стекну школске и друге вештине значајне за свакодневено животно функционисање. Важно је напоменути да поред тежине слушног оштећења, интелектуалних и других способности детета, као и приступ рада наставника- сурдолога, индивидуални приступ у раду са сваким дететом представља велику значајност у оспособљавању и учењу деце са оштећењем слуха. У циљу што бољег оспособљавања глуве и наглуве деце важно је истаћи и постојеће методе и средства која се користе у настави како би комуникација била олакшана. Дактилологија или прстна азбука представља једно од основних средстава у комуникацији особа са оштећењима слуха. Основни задатак је да се олакша читање говора са уста и лица, као и да се побољша артикулација у развоју говора. Важно је напоменути да сваки језик има своју прстну азбуку. Када је реч о српском знаковном језику, користи се дворучна азбука, док код неких других знаковних језика употребљава се и једноручни алфабет. Српски знаковни језик је веома богат и сложен језик, те захтева и велику посвећеност при учењу овог језика. Предмет овог рада је функција дактилологије у развоју језика код глувих и наглувих ученика. Циљ рада је да се укаже на значај дактилологије као средства за равој говора код глуве и наглуве деце. У раду ће бити примењена дескриптивна метода заснована на пређашњој литератури која се бавила овом темом.Speech is the most important means of communication and the overall development of a child depends on its development. Speech development is a long and complex process, which has its own specific stages of development. Factors that directly affect speech development and that are a prerequisite for proper speech development are numerous. One of the important factors in the development of speech is hearing, and its damage entails a number of problems that occur in children with hearing impairments. The importance of working with children with hearing impairments is reflected in the specific development of speech, which will later enable them to acquire school and other skills important for everyday life functioning. It is important to note that in addition to the severity of hearing impairment, intellectual and other abilities of the child, as well as the approach of the deaf teacher, an individual approach to working with each child is of great importance in the training and learning of children with hearing impairments. In order to better train deaf and hard of hearing children, it is important to point out the existing methods and tools used in teaching in order to facilitate communication. Typing or chest alphabet is one of the basic means of communication for people with hearing impairments. The basic task is to facilitate the reading of speech from the mouth and face, as well as to improve the articulation in the development of speech. It is important to note that each language has its own chest alphabet. When it comes to Serbian sign language, the two-handed alphabet is used, while in some other sign languages the one-handed alphabet is also used. Serbian sign language is a very rich and complex language, and it requires great dedication in learning this language. The subject of this paper is the function of dactylology in language development in deaf and hard of hearing students. The aim of this paper is to point out the importance of dactylology as a means for speech development in deaf and hard of hearing children. The paper will use a descriptive method based on previous literature that has dealt with this topic

One year mortality associated with chronic dialysis: a comparison between urgent and elective start

CILJ ISTRAŽIVANJA. Ispitati jednogodišnje preživljenje u ovisnosti o elektivnom ili urgentnom početku liječenja kroničnom HD-om te rizične čimbenike za urgentan početak HD-a. NACRT STUDIJE. Povijesno kohortno istraživanje. ISPITANICI I METODE. U istraživanje je uključeno 130 bolesnika (82 muška, medijan dobi 65,5 godina, od 17 do 89) s dostupnim podatcima (od ukupno 138) koji su započeli liječenje kroničnom HD-om na Odjelu za dijalizu Kliničkog bolničkog centra Osijek, od 1.1.2013. do 31.12.2014. godine. Podatci su prikupljeni iz medicinskih zapisa i statistički obrađeni pomoću SPSS-a. REZULTATI. Bolesnici s urgentnim početkom kronične HD (69 %) imali su veći mortalitet u prvoj godini liječenja u odnosu na one koji su počeli elektivno (30,3 % vs 7,5 %; P = 0,015), bili su stariji (P = 0,060), češće imali krvožilni pristup putem SVK-a (91,01 % vs 50 %), više serumske koncentracije ureje te niže albumina. ZAKLJUČAK. Urgentni početak kronične HD je čest i praćen nižim jednogodišnjim preživljenjem u odnosu na one koji elektivno započinju liječenje. Čak jedna trećina urgentnih bolesnika umrla je tijekom prve godine liječenja. Identifikacija rizičnih čimbenika urgentnog početka kronične HD i optimalan početak liječenja mogla bi utjecati na smanjenje smrtnosti tih bolesnika.OBJECTIVES. To examine one year survival with regard to elective or urgent chronic hemodialysis (HD) start and to identify the urgent start risk factors. STUDY DESIGN. Historical cohort study. PARTICIPANS AND METHODS. Study included 130 patients (82 men, median age 65.5 years, from 17 to 89) with available data (out of total 138 incidents) starting chronic HD in University Hospital Osijek from 1 January 2013 until 31 December 2014. Data were taken from medical records and statistically analyzed by SPSS. RESULTS. Patients with urgent chronic HD start (69%) had higher one year mortality in comparison with those starting electively (30.3 % vs 7.5 %;, P = 0.015), were older (P = 0.060), had more often central venous catheter as vascular access (91.01 % vs 50 %), higher serum urea and lower albuminemia. CONCLUSION. Urgent chronic HD start is frequent an followed by lower one year survival in comparison with elective start. Even one third of urgently starting patients died during the first year on HD. Risk factors identification for urgent chronic HD start and optimal timing for the treatment could render mortality reduction in those patients

Quality of problem-oriented teaching and students' achievement

U disertaciji se proučavaju mogućnosti i načini primene problemski orijentisane nastave u školskoj praksi. Temu disertacije odredilo je interesovanje da se istraži u kojoj meri se ključna svojstva problemski orijentisane nastave, kao što su istraživačka i stvaralačka delatnost, intelektualno zahtevne aktivnosti, samostalnost učenika i druge, mogu staviti u funkciju intelektualnog vaspitanja. Osim toga, okvire teme postavili su podaci koji dolaze iz teorije i prakse. Iako brojna inostrana, međunarodna i domaća istraživanja potvrđuju nesumnjivu efikasnost ovog načina rada u ostvarivanju vaspitno-obrazovnih ciljeva, uopšteno posmatrano problemski način rada nije šire prihvaćen u nastavnoj praksi. S tim u vezi, cilj ovog rada je da se prošire dosadašnja saznanja o obimu zastupljenosti, kvalitetu primene i karakteristikama realizacije problemski orijentisane nastave, kao i efektu koji tako organizovana nastava ima na nivo i kvalitet učeničkog postignuća u nastavi matematike i biologije. U istraživanju je učestvovalo 196 nastavnika, i to 97 nastavnika matematike i 99 nastavnika biologije, kao i njihovi učenici kojih je ukupno bilo 1117. Korišćena je deskriptivno-analitička metoda, a podaci su prikupljeni pomoću tehnike analize sadržaja, anketiranja, skaliranja i testiranja. Rezultati istraživanja pokazuju da je problemski orijentisana nastava optimalno zastupljen način nastavnog rada u nastavi matematike, dok je u nastavi biologije zastupljena u nešto manjem obimu. Učenici čiji nastavnici često primenjuju problemski orijentisanu nastavu ostvaruju bolja postignuća u odnosu na učenike čiji nastavnici retko primenjuju ovaj način rada. U pogledu prirode problema, učenici najčešće rešavaju probleme koji sadrže veći broj informacija u tekstu, dok se najređe suočavaju sa problemima koji imaju više tačnih rešenja. Učenici uglavnom procenjuju da u toku rešavanja problema realizuju aktivnosti problemski orijentisane nastave. Ispitivanjem kvaliteta njihove realizacije ustanovljeno je da učenici ne posvećuju dovoljno pažnje početnim aktivnostima rešavanja problema, kao i vrednovanju ostvarenih rezultata. Utvrđene su pozitivne korelacije između ispitanih svojstava problema i postignuća učenika, kao i između učestalosti i kvaliteta realizacije aktivnosti problemski orijentisane nastave i postignuća učenika. Problemski orijentisana nastava uglavnom se realizuje na časovima utvrđivanja, posredstvom dijaloške metode i primenom individualnog oblika rada u nastavi matematike, a posredstvom frontalnog oblika rada u nastavi biologije.The dissertation observes the possibilities and the ways of applying problem-oriented teaching in school practice. The theme of this dissertation is determined by the interest in exploring the extent to which the main features of problem-oriented teaching, such as: research and creative activity, intellectually demanding activities, students' autonomy and others, can be used for intellectual education. In addition, the data that come from theory and practice set the frame of the topic. Although the numerous of foreign, international and domestic researches confirm doubtless effectiveness of this mode in achieving educational goals, generally speaking the problem solving mode is not widely accepted in practice. In this regard, the aim of this study is to expand the usage of the existing knowledge, the quality of application and the characteristics of the realization of problem- oriented teaching, and the effect that such organized teaching has on the level and quality of students’ achievement in teaching mathematics and biology. The research involved 196 teachers, including 97 teachers of mathematics and 99 biology teachers, as well as their 1117students altogether. The descriptive-analytical method was used, and the data was collected by using content analysis, surveying, scaling and testing techniques. The results of the research show that problem-oriented teaching is optimally used in teaching mathematics, while in the teaching of biology it is much less used. Students whose teachers use problem-oriented teaching show better achievement than those students whose teachers rarely use this way of teaching.Regarding the nature of the problems, students often solve problems that contain large number of information in the text, while they the most rarely face with problems that have more accurate solutions. Students generally estimate that during the problem-solving activities the problem-oriented teaching is implemented. By examining the quality of their activities, it was found that students do not pay enough attention to the initial activities of solving the problems, as well as to the evaluation of the achieved results. Positive correlations were determined between the tested features of the problems and students’ achievements, as well as between the frequency and the quality of the realization of the problem-oriented teaching’s activities and students’ achievements. Problem -oriented teaching is mainly realized at the classes of assessment, through the dialect method and by applying individual forms of work in the teaching mathematics, and through the frontal form of work in the teaching of biology

Humus composition of rendzina soils in different environmental conditions of Serbia

This paper shows organic matter composition (humic acids, fulvic acids, humins) and fractions of humic (free and bounded with mobile R2O3 (HAI), bounded with Ca (HA2), and bounded with clay and stabile R2O3 (HA3)), and fulvo acids (free and bounded with mobile R2O3), bounded with HA1 bounded with HA2, and bounded with HA3), in Rendzina soils on different altitudes (151-1210 m), landforms (hilltop, flat or very gentle slope; foot slope, very gentle slope, south, southwest; slope 45-80 degrees, south, southeast, southwest; slope 20-60 degrees, north, northwest, northeast), and regions (Srem, west, central, east and southeast Serbia). Differences in temperature and water regimes of Rendzinas on various altitudes are not so prominent to have a significant impact on organic matter composition. Landform has more significant impact, with average higher content of HA on slopes, and FA on flat positions, which could be attributed to reduced wetting of soils on slopes. Exposition had no significant impact on humus composition. Differences in soil moisture among regions are more pronounced than differences in soil temperature. Differences in soil organic matter composition among Rendzinas from various regions are small and do not follow pattern of humidity change. Still, organic matter of Rendzina from most humid western region has the least favourable HA/FA ratio, while at the driest east and southeast regions content of humin is the greatest

Genotypic variability of morphological characteristics of English oak (Quercus robur L) acorn

This paper deals with the acorn morphology (length, diameter and mass) analyzed in seventeen English oak genotypes (Quercus robur L)from the English Oak Clonal Seed Orchard Banov Brod (Srem,Vojvodina). The highest values of acorn mass and length were measured in genotype 5. The largest diameters were measured in genotypes 6 and 21. Genotype 35 had the lowest acorn mass, length and diameter. The results from this study should serve as guidelines for the selection of trees yielding fruits possessing the desirable morphological characteristics

Humic acids optical properties of rendzina soils in diverse environmental conditions of Serbia

This study examined the impact of climate, altitude and landforms on humic acids (HA) optical properties (E-4/E-6, Delta logK, RF indexes) in Serbian Rendzina soils. HA humification degree of calcareous and decarbonated Rendzinas under natural vegetation (forest and grassland, separately) decreased with altitude increasing. This particular rule was not manifested in arable Rendzinas. HA humification degree in Rendzinas on flat positions (hilltop and footslope) is significantly higher than in Rendzinas on slope sides. Humification degree of HA is the highest in Rendzinas in eastern Serbia (in the vicinity of Negotin), followed by central Serbia (Sumadija) and Srem, southeast and finally, southeast and southwest Serbia. With respect to the climate change foreseen for the end of this century, i.e. increase of precipitation and temperature variance among the regions in Serbia, also an increase in variance of quality of humic acids in Rendzinas on different altitudes and regions can be expected

Influence of environmental conditions on carbon and nitrogen content in Serbian rendzina soils

Organic matter in Serbian Rendzina soils dependence on altitude and geographic regions was investigated. There was no regular dynamics of carbon and nitrogen content nor in C/N ratio, probably because of slight climatic variation among altitudes and regions, thus negligible differences in vegetation, organic litter and decomposition dynamics. Predicted climatic changes, uneven for regions, will exert a complex influence on soil C and N storage. These results should be used as a base for future monitoring of C and N content in Serbian Rendzina soils and their dependence on climate

Dinamika stratosferskog ozona i ultravioletno zračenje iznad Srbije

Increased ultraviolet radiation potentially detrimental to health is a direct effect of the reduced ozone layer of the Earth's atmosphere. Stratospheric ozone over the territory of Serbia and immediate surrounding depleted in the considered period of 1979-2008; its amount reduced by 7.6%. Solar and volcanic activities have significant effect on the interannual variability of the stratospheric ozone. Ozone layer over Serbia is 13.8% thicker than the planetary layer, with the ozone hole forming once in five years on average without serious health implications.Smanjenje debljine ozonskog omotača Zemlje direktno utiče na povećanje ultravioletnog zračenja sa potencijalnim efektima na zdravlje ljudi. U radu je ispitivana dinamika stratosferskog ozona nad teritorijama Srbije i neposrednog okruženja u periodu 1979-2008. godine. Konstatovan je kumulativni pad debljine ozona za 7.6%. Ukazano je na uticaj Sunčeve i vulkanske aktivnosti na međugodišnju varijabilnost debljine stratosferskog ozona. Debljina ozonskog omotača nad teritorijom Srbije je za 13.8% veća od planetarne, a ozonske 'rupe' se javljaju prosečno jednom u 5 godina i ne predstavljaju ozbiljniju pretnju po zdravlje stanovništva