Research Perspectives of Initial Geometry Education

The paper discusses the perspectives of teaching geometry based on the study The International Commission on Mathematical Instruction ICMI. Bearing in mind the current needs in geometry teaching, we considered that the topics of space and spatial reasoning should be part of it as key issues, as well as teaching approaches, RME, learning through (re)discovering mathematical ideas, the role of textbooks in the initial mathematics education, and so on. Therefore, this research paper offers a general insight into our need to deal with these topics, and invites researchers from the broader mathematical community, who we herewith familiarize with the results of our research in the sphere of initial geometry teaching in Serbia

Realistic mathematics In teaching and learning elementary geometry

Основни циљ почетне наставе математике је да ученике математички описменимо, а заступници смо гледишта да су циљеви, поред наведеног, и стварање стања упитаности, тежња ка стварању истраживачког духа ученика, као и осећаја за успостављање веза формалне математике са једне стране са појавама из реалног окружења са друге. Ово нас је довело до реалног окружења као једног од могућих наставних приступа који успоставља такве везе. Рад се састоји од четири основна поглавља са више подпоглавља. Бавили смо се теоријским и експерименталним испитивањем и проучавањем ефеката наставног приступа реално окружење у почетној настави геометрије базираног на теорији реалистичног математичког образовања подржан пропратним иновативним моделом уџбеника. Издвојили смо три циља рада. Први се односио на проучавање теоријских основа (геометријских и дидактичко-методичких) употребом методе теоријске анализе. Указали смо на неке међународне и домаће пројекте које у својим концепцијама математичког образовања за основно полазиште користе реално окружење. Други циљ односио се на представљање резултата експерименталног дела нашег истраживања којим смо испитали на који начин реално окружење у геометријским садржајима IV разреда почетне наставе математике утиче на постигнућа ученика (по нивоима знања) и резоновање, као и ученичку мотивацију за учење. Овде смо употребили експерименталну методу. И, коначно, трећи циљ односио се на представљање иновативног модела уџбеника као практичне имплементације који подржава конструктивистички приступ настави у реалном окружењу, а указали смо и на кључне резултате и њихове методичке импликације на почетну наставу математике добијене на основу експерименталног истраживања. Наше истраживање било је усмерено на откривање пута шта води ученике до појмова са значењем од, са једне стране, визуелних представа до, са друге стране, вербалних уопштавaња и анализа, наглашавајући повезаност визуелног и вербалног процеса као значајне у ученичком раду и изграђивању математичких појмова у математичкој свести ученика. На тој основи следили смо идеје изграђивања и елаборирања постојеће интуиције о простору, развијајући безусловно и геометријску интуицију. Додајући овоме и конструктивистички поглед, у истраживању смо се бавили развојем геометријских појмова и геометријског мишљења у реалистичном окружењу у коме се учи...The main aim of teaching elementary mathematics is to make students mathematically literate. This is why we advocate the view that aims, apart from the stated ones, are, as well, creating the states of curiosity, tendency towards crating researching minds of students and the sense for creating connections between formal Mathematics on one side and appearances from real environment on the other side. This has led us to realistic mathematics as one of the possible teaching approaches towards creating such a connection. There are four basic chapters and many sub-chapters. We have done both theoretical and experimental research and studying effects of the teaching approach to realistic mathematics in teaching elementary geometry based on the theory of realistic mathematical education supported by the additional innovative model of the course book. We have selected three aims of the paper. The first refers to studying theoretical bases (geometrical and didactic-methodological) by using the method of theoretical analysis. We have pointed at some international and domestic projects, which in their concepts of mathematical education, use realistic mathematics for their starting point. The second aim refers to presenting results of the experimental part of our research which is aimed at the examining ways in which realistic mathematics in geometry contents of the fourth grade of teaching elementary Mathematics influences the students‟ achievements (according to the levels of knowledge) and reasoning, as well as students‟ motivation for learning. We have used the experiential method here. Finally, the third aim refers to referring the innovative model of the textbook as practical implementation, which supports constructivist approach in teaching realistic mathematics, and we pointed at key results and their methodological implications on teaching elementary Mathematics gained according to experiential research. Our research is directed to revealing to the way, which leads the students to terms with meaning, from, on one side, visual concepts to, on the other hand verbal generalizations and analyses, stressing the connection between visual and verbal process as an important issue in mathematical mind of students. On this basis, we followed the ideas of building up and elaborating the existing intuition about space, developing, unconditionally geometrical intuition. Adding constructivist approach, in the research we have dealt with development of geometrical terms and geometrical thinking in realistic mathematics in which students learn. We have studies development of students‟ knowledge in realistic mathematics, as well as how teachers use this from learning and how this process occurs..

Laser Interaction with Material - Theory, Experiments and Discrepancies

The experimental treatment of chosen material with laser beams, starting from continuous wave up to fs pulses, produces the necessity to find the common and sophisticated theoretical approaches to interaction modeling. For chosen materials, some laser treatment and damage analyses are performed. The provoked stresses and parameters of transport processes (penetration depth) are calculated by using the programs for electrical circuit analyses. Some inconsistencies in the treatment of large area laser-material interaction are discussed

Wild Boar Tissue Levels of Cadmium, Lead and Mercury in Seven Regions of Continental Croatia

Concentrations of cadmium, mercury and lead were analysed by atomic absorption spectrometry in the kidney and muscle of free-living wild boar (n = 169) from hunting grounds in seven counties of continental Croatia. Mean levels of metals (mg/kg) in muscle and kidney of boars ranged as follows: Cd: 0.005–0.016 and 0.866–4.58, Pb: 0.033–0.15 and 0.036–0.441, Hg: 0.004–0.012 and 0.04–0.152. In all seven regions, concentrations exceeded the permitted values (muscle and kidney mg/kg: cadmium 0.05/1; lead 0.1/0.5; mercury 0.03/0.1) in 13.6% and 71.6% of samples (muscle and kidney, respectively) for cadmium; 13.6% and 8.9% for lead; 19.5% and 2.4% for mercury. There were significant differences among the regions. Vukovar-Srijem and Virovitica-Podravina Counties were highly contaminated with cadmium, Sisak-Moslavina and Virovitica-Podravina Counties with lead and Brod-Posavina County had highest mercury concentrations. These results suggest a detailed investigation of physiological and environmental factors contributing to accumulation of metals in boars

Investigating possibilities for synthesis of novel sorbents and catalyst carriers based on ceramics with controlled open porosity

The aim of this study was to investigate a possibility of synthesis of porous ceramics with controlled open porosity, which could be used as sorbents and catalyst supports. Two organic additives were used to obtain open porosity: polystyrene beads and cellulose fibers, which are mixed with kaolin clay powder and the appropriate water content. Samples were sintered at 1050 oC for 1 h. Characterization of the obtained products included X-ray powder diffraction analysis (XRPD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and elemental CHNS analysis. In addition, porosity was examined by quantification of visual information. The specific surface areas were determined by the Brunauer–Emmett–Teller (BET) method. Also, density and compressive strength of the obtained samples were assessed. It was determined that by sintering, the organic component completely leaves the system. For samples prepared with polystyrene beads and with cellulose fibers, satisfactory mechanical properties were obtained: compressive strengths were 1.42 and 1.56 MPa, respectively. It was noted that significantly higher open porosity was obtained by using polystyrene beads as a sacrificial template (porosity of ̴56 %) instead of cellulose fibers (porosity of ̴6 %)

Coming full circle: Differential empowerment in the EU accession process

The EU accession process brings a profound transformation not only to candidate countries’ institutions and policies, but also to the political opportunity structure in place, creating new possibilities for previously marginalised actors. Studying the differential empowerment of NGOs throughout the Croatian accession process, this paper makes two related claims: first, differential empowerment depends crucially on domestic actors’ awareness for and ability to use new opportunities to their advantage. Second, an overreliance on EU leverage poses important temporal and substantive limits on NGO empowerment and leads to a rapid decline of their relevance in the post-accession phase. I argue that a more sustainable shift in the domestic power balance would require both the EU and domestic civil society actors to place more emphasis on fostering improved practices of civil society inclusion in domestic policymaking settings throughout the accession process

Sinteza inovativnih keramičkih sorbenata i nosača katalizatora hijerarhijske poroznosti

Porozna keramika sa industrijskog aspekta predstavlja značajan materijal, međutim, za njenu pripremu se još uvek traže ekonomski i tehnološki prihvatljiva rešenja. Kontrola poroznosti predstavlja ključan korak u postizanju željenih svojstava za određenu primenu. U cilju dobijanja multiporozne keramike u ovom radu korišćena je kaolinska glina i polistirenske perle kao organska žrtvena faza. Uzorci su nakon mešanja sinterovani na 1050 oC tokom 1 h. Karakterizacija je obuhvatila infracrvenu spektroskopiju sa Furijeovom transformacijom (FTIR), kenirajuću elektronsku mikroskopiju (SEM), rendgensku difrakcionu analizu (XRPD), elementnu CHNS analizu i ispitivanje pritisne čvrstoće. Analiza dobijenih rezultata pokazala je da se hijerarhijski uređena, multiporozna keramika, odgovarajućih mehaničkih svojstava može pripremiti u prisustvu organske komponente čijim sagorevanjem tokom sinterovanja zaostaju pore različitih dimenzija.From an industrial point of view, porous ceramics represent an important material, however, economically and technologically acceptable solutions are still being sought for its preparation. Porosity control is a key step in achieving the desired properties for a specific application. In order to obtain multiporous ceramics, in this work, kaolin clay and polystyrene beads were used as organic sacrificial phase. After mixing, the samples were sintered at 1050 oC for 1 h. Characterization included Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction analysis (XRPD), elemental CHNS analysis and compressive strength investigations. The analysis of the obtained results showed that hierarchically ordered, multiporous ceramics, with appropriate mechanical properties can be prepared in the presence of an organic component whose burnout during sintering leaves behind pores of different dimensions

All hands on deck: levels of dependence between the EU and other international organizations in peacebuilding

The EU seeks extensive partnership with other international organizations when it comes to security challenges. This is puzzling as the EU relies for its resources mostly on its member states. The relations between the EU and other international organizations have thoroughly been studied, yet scholars rarely question the actual rationale for partnership. We start from resource dependency theory which explains that almost all organizations are dependent on the resources of their partners. Yet we extend this theory by distinguishing between macro, meso and micro-level dependencies. To illustrate resource dependencies between the EU and other international organizations, we analyse EU’s peacebuilding policies in Kosovo, Mali and Armenia. By accounting for macro- and micro-level dependencies we provide a more holistic perspective than conventional meso-level explanations. Our contribution is therefore to expand the scope of the resource dependency theory and provide a framework to analyse dependencies between the EU and other international organizations

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field