The Dark Matter equation of state through cosmic history

Cold Dark Matter (CDM) is a crucial constituent of the current concordance cosmological model. Having a vanishing equation of state (EoS), its energy density scales with the inverse cosmic volume and is thus uniquely described by a single number, its present abundance. We test the inverse cosmic volume law for Dark Matter (DM) by allowing its EoS to vary independently in eight redshift bins in the range $z=10^5$ and $z=0$. We use the latest measurements of the Cosmic Microwave Background radiation from the Planck satellite and supplement them with Baryon Acoustic Oscillation (BAO) data from the 6dF and SDSS-III BOSS surveys, and with the Hubble Space Telescope (HST) key project data. We find no evidence for nonzero EoS in any of the eight redshift bins. With Planck data alone, the DM abundance is most strongly constrained around matter-radiation equality $\omega^{\rm eq}_g = 0.1193^{+0.0036}_{-0.0035}$ (95% c.l.), whereas its present day value is more weakly constrained $\omega^{(0)}_g = 0.16^{+0.12}_{-0.10}$ (95% c.l.). Adding BAO or HST data does not significantly change the $\omega^{\rm eq}_g$ constraint, while $\omega^{(0)}_g$ tightens to $0.160^{+0.069}_{-0.065}$ (95% c.l.) and $0.124^{+0.081}_{-0.067}$ (95% c.l.) respectively. Our results constrain for the first time the level of "coldness" required of the DM across various cosmological epochs and show that the DM abundance is strictly positive at all times.Comment: 6 pages, 4 figures, changed color scheme for figure

Znanje i stavovi beogradskih studenata medicine i stomatologije o upravljanju medicinskim otpadom

Introduction/Objective Knowledge and practical skills in medical waste (MW) management are of equal importance for medical and dental doctors. The first comparative study on the knowledge and skills in the field of MW management among Belgrade students was conducted with the goal of examining whether students of medicine and dentistry are equally familiar with this extremely important field. Methods a cross-sectional study included 558 students of the sixth year of studies (430 medical and 128 dental students) who completed an anonymous semi-structured questionnaire to determine attitudes and knowledge on MW management. Results the majority of medical and dental students had no training in MW management (79.5% and 74.6%, respectively). Dental students use protective equipment more frequently than medical students (94.5% vs. 42%, p lt 0.001). However, full vaccinal protection against hepatitis B is better among medical students compared to dental students (57.7% vs. 39.1%, p lt 0.001). Complete knowledge on postexposal prophylaxis is better among medical students compared to dental students (44.5% vs. 13.3%, p lt 0.001). However, dental students are more disciplined in reporting injuries (63.1% vs. 52.4%, p = 0.038). The students' knowledge on primary separation of infectious waste (93% vs. 77.8%, p lt 0.001) and used needles (80.3% vs. 70.4%, p = 0.007) is better among dental students compared to medical students' correct answers. Conclusion Dental students show better knowledge on MW management and are more disciplined in using personal infection protection compared to medical students. The students support continued training on MW management and investigations on this topic.Uvod/Cilj Znanje i praktične veštine upravljanja medicinskim otpadom su od posebnog značaja za doktore medicine i stomatologije. Komparativna studija o znanju i veštinama iz oblasti upravljanja medicinskim otpadom sprovedena je među beogradskim studentima prvi put, u cilju ispitivanja da li ovom izuzetno važnom oblašću studenti medicine i stomatologije vladaju podjednako dobro. Metode Ova studija preseka obuhvatila je 558 studenata šeste godine studija na Beogradskom univerzitetu (430 studenata medicine i 128 studenata stomatologije), koji su popunili anonimni upitnik o znanju i stavovima o upravljanju medicinskim otpadom. Rezultati Većina studenata stomatologije i medicine nisu imali nikakvu posebnu obuku iz upravljanja medicinskim otpadom (79,5% i 74,6%). Studenti stomatologije su češće koristili zaštitnu opremu (94,5% prema 42%, p lt 0,001). Vakcinalna zaštita od hepatitisa B je kompletnija među studentima medicine u odnosu na studente stomatologije (57,7% prema 39,1%, p lt 0,001). Znanje o profilaksi posle izloženosti bolja je među studentima medicine (44,5% prema 13,3%, p lt 0,001). Međutim, studenti stomatologije su ažurniji u pogledu prijavljivanja povreda na radnom mestu (63,1% prema 52,4%, p = 0,038). Znanje studenata o primarnoj separaciji infektivnog otpada i korišćenih igala je bolje među budućim stomatolozima (tačni odgovori 93% nasuprot 77,8%; p lt 0,001 i 80,3% prema 70,4%; p = 0,007). Zaključak Studenti stomatologije imaju bolje znanje o upravljanju medicinskim otpadom i disciplinovaniji su u pogledu korišćenja zaštitne opreme na radu u odnosu na studente medicine. Studenti podržavaju kontinuiranu edukaciju o upravljanju medicinskim otpadom i dalja istraživanja o ovoj temi

Roncus ivansticae (Neobisiidae, Pseudoscorpiones): A new epigean species from eastern Serbia

A single species of Roncus L. Koch, 1873, which was collected in eastern Serbia and is new to science (R. ivansticae n. sp.) is described herein; the diagnostic characters are illustrated and their distribution is provided. The possible establishment of two species (or supraspecific?) groups of Roncus is presented briefly in view of the importance of some diagnostic characters

Influence of shape complexity, material, Stress concentration and temperature To designing of welded constructions

U ovoj doktorskoj disertaciji zavarena konstrukcija je posmatrana kao složen sistem elemenata sa kompleksnim interakcijama koji su heterogeni iz aspekta materijala, oblika i dimenzija, mehaničkih karakteristika, kao i eksploatacionih i funkcionalnih uslova. Heterogenost elemenata zavarene konstrukcije uslovljava njihove različite karakteristike i odgovore na opterećenje, dok nehomogenost njihove mikrostrukture uslovljava i dodatno usložnjava naponsko-deformaciono stanje. Specifičnosti projektovanja zavarenih mašinskih konstrukcija sagledane su iz aspekta složenosti oblika, materijala, koncentracije napona i temperature eksploatacije. Eksperimentalno određivanje mehaničkih karakteristika i analiza ponašanja u eksploatacionim uslovima, na sobnoj i povišenim temperaturama, izvedena je na modelima od mikrolegiranog čelika povišene jačine. Ispitivani modeli pored zone zavarenog spoja sadrže i zonu geometrijskog diskontinuiteta kao dodatni izvor koncentracije napona što je čest slučaj kod elemenata zavarenih konstrukcija. Skup faktora koji uslovljavaju projektovanje zavarenih konstrukcija identifikovan je sveobuhvatnom analizom eksperimentalnih rezultata i verifikovan je teorijskim razmatranjem naponsko-deformacionog stanja koje nastaje kod razmatranih modela. Posebna pažnja je posvećena analizi mehaničkih osobina i karakteristika mikrolegiranih čelika povišene jačine za izradu veoma odgovornih zavarenih mašinskih konstrukcija, kao savremenog materijala, čija upotreba omogućava ostvarivanje niza prednosti, ali sa sobom donosi i specifične probleme koji moraju biti adekvatno rešeni tokom procesa projektovanja ovih konstrukcija. Identifikovanjem faktora koji određuju konstrukciono rešenje zavarenih mašinskih konstrukcija i utvrđivanjem njihovog uticaja date su preporuke kojima se utemeljuje racionalno korišćenje materijala i energije, ostvaruje smanjenje ukupnih troškova uz prihvatljive ekološke efekte i istovremeno unapređuje sigurnost i pouzdanost zavarenih mašinskih konstrukcija.In this dissertation welded constructions are analyzed as complex systems of elements with complex mechanisms of interactions that are heterogeneous from the aspects of materials, shape and dimensions, mechanical properties, so as exploitation and functional conditions. Heterogeneity of elements of welded constructions cause their different characteristics and their different response to load, while inhomogeneity of their microstructure cause complex stress-strain state so as additional complication of this state. The specific characteristics of welded constructions design are highlighted from the aspect of shape complexity, material, stress concentrations and exploitation temperature. Experimental determination of mechanical properties and analysis of mechanical response to load during exploitation at room and elevated temperatures were done at models made of low alloyed high strength steel. Tested models besides zone of welded joint have zone of geometrical discontinuities as additional source of stress concentration that is common case at elements of welded mechanical constructions. Set of parameters that influent to design of welded constructions is identificated by analysis of experimental results and verified by theoretical considerations of stress-strain state at tested models. Special focus is put on analysis of characteristics and mechanical properties of low alloyed high strength steels for welded mechanical constructions as present material with usage that obtain number of advances, but also bring some specific problems that must be solved during process of design of those constructions. By identification of factors that influent to constructional solution of welded construction and determination of their influence, recommendations are given to establish rational usage of material and energy, obtained reduction of total costs with minimal ecological impact and with simultaneous improve of safety and reliability of welded constructions

Revealing the nature of central emission nebulae in the dwarf galaxy NGC 185

In this paper we present new optical observations of the galaxy NGC 185 intended to reveal the status of supernova remnants (SNRs) in this dwarf companion of the Andromeda galaxy. Previously, it was reported that this galaxy hosts one SNR. Our deep photometric study with the 2m telescope at Rozhen National Astronomical Observatory using narrow-band H$\alpha$ and [SII] filters revealed complex structure of the interstellar medium in the center of the galaxy. To confirm the classification and to study the kinematics of the detected nebulae, we carried out spectroscopic observations using the SCORPIO multi-mode spectrograph at the 6m telescope at the Special Astrophysical Observatory of the Russian Academy of Science, both in low- and high-resolution modes. We also searched the archival X-ray and radio data for counterparts of the candidate SNRs identified by our optical observations. Our observations imply the presence of one more SNR, one possible HII region previously cataloged as part of an SNR, and the presence of an additional source of shock ionization in one low-brightness PN. We detected enhanced [SII]/H_alpha and [NII]/H_alpha line ratios, as well as relatively high (up to 90 km s$^{-1}$) expansion velocities of the two observed nebulae, motivating their classification as SNRs (with diameters of 45 pc and 50 pc), confirmed by both photometric and spectral observations. The estimated electron density of emission nebulae is 30 - 200 cm$^{-3}$. Archival XMM-Newton observations indicate the presence of an extended, low-brightness, soft source in projection of one of the optical SNRs, whereas the archival VLA radio image shows weak, unresolved emission in the center of NGC 185.Comment: 15 pages, 14 figures, accepted for publication in A&

The effect of VHL gene mutation on the expression levels of mTOR signaling pathway proteins in clear cell renal cell carcinoma

Sporadični svetloćelijski karcinomi bubrega asocirani su sa mutacijama tumor supresorskog gena VHL kod 60-80 % pacijenata. U odsustvu funkcionalnog proteina VHL dolazi do akumulacije faktora indukovanih hipoksijom koji regulišu ekspresiju gena uključenih u procese angiogeneze, eritropoeze, ćelijskog metabolizma i preživljavanja. Pored specifičnog genetičkog profila i povišenog nivoa HIF-2α svetloćelijske karcinome bubrega karakteriše glikolitički metabolički put i povišena aktivnost mTOR signalnog puta. Nepovoljan energetski status i hipoksija blokiraju aktivnost mTOR signalnog puta preko proteina AMPK i REDD1. Ova studija imala je za cilj da utvrdi mogću asocijaciju mutacionog statusa gena VHL sa patohistološkim parametrima, nivoom HIF-2α iRNK i nivoom proteina HIF-2α, mTOR, TSC1, TSC2, eIF4E-BP1, p70S6K1, AMPK, REDD1 i PDK3 u svetloćelijskom karcinomu bubrega. Studija je obuhvatala 47 pacijenata kojima je urađena totalna nefrektomija zbog prisustva svetloćelijskog karcinoma bubrega. Genomska DNK izolovana iz uzoraka venske krvi i somatska DNK izolovana iz uzoraka tumorskog i neizmenjenog tkiva bubrega upotrebljene su za određivanje mutacionog statusa gena VHL i gubitka heterozigotnosti 3p lokusa sekvenciranjem, metodom amplifikacije višestruko ligiranih proba i fragmentnom analizom mikrosatelitnih markera. Metilacioni status promotora gena VHL ispitan je metil specifičnom PCR reakcijom nakon bisulfitne modifikacije DNK. Kvantitativni RT-PCR primenjen je za relativnu kvantifikaciju HIF-2α iRNK u tumorskom i neizmenjenog tkivu bubrega. Kvantitafikacija ekspresije proteina HIF-2α, mTOR, TSC1, eIF4E-BP1, p70S6K1, AMPK, REDD1 i PDK3 utvrđena je Western blot metodom. Semikvantitativna imunohistohemijska analiza korišćena je za utvrđivanje nivoa ekpresije proteina TSC2...Sporadic clear cell renal carcinoma is associated with mutations of the VHL gene in 60-80 % patients. The absence of a functional VHL protein leads to accumulation of hypoxia-inducible factors which regulate expression of genes involved in angiogenesis, erythropoiesis, cell metabolism and survival. Specific genetic background, overexpression of HIF-2α transcription factor as well as glycolytic metabolism and upregulated activity of mTOR pathway are the main characteristics of clear cell renal carcinoma. The lack of energy and hypoxia inhibit mTOR signaling through activity of AMPK and REDD1 proteins. The aim of present study was to determine association of VHL gene mutational status with pathohistological parameters, expression level of mRNA HIF-2α and expression levels of mTOR, TSC1, TSC2, eIF4E-BP1, p70S6K1, AMPK, REDD1 and PDK3 proteins in clear cell renal carcinoma. The study included 47 patients who underwent radical nephrectomy due to unilateral kidney tumor. DNA was extracted from peripheral venous blood, tumorous and corresponding healthy renal tissue. The VHL gene mutational status and loss of heterozigosity of 3p loci were detected using DNA sequencing, MLPA and analysis of microsatellite markers. The VHL gene promoter methylation analysis was examined by MS-PCR after bisulphite modification of DNA. Quantitative real time PCR was performed for relative quantification of HIF-2 alpha mRNA. Expression levels of HIF- 2α, mTOR, TSC1, eIF4E-BP1, p70S6K1, AMPK, REDD1 and PDK3 proteins was determined using Western blot method. Immunohistochemistry was performed for semiquantitative analysis of TSC2 protein. Alteration of VHL gene and/or changes of 3p loci were detected in 37/47 (78.7 %) analysed tumorous samples..

The analysis of particles emission during the process of grinding of steel EN 90MNV8

Metal grinding is a one of the manufacturing technologies that is greatly connected to particles emission. Particles generated during the grinding process are dangerous in terms of its potential penetration deeply into the lungs of an operator. The level of risk for human respiratory system is related to nature, shape and size of the particles, and for this reason it is important to have a quality characterization of emitted particles. This paper focuses on particles characterization on the bases of image analysis from scanning electron microscopy (SEM). The research was conducted during the process of grinding of steel EN 90MnV8, using personal sampler. Results of image analysis, consisted of Feret’s diameter and circularity, showed quite a wide range of sizes and significant deviation of particles from regular shape

Specific purpose language teaching within the context of the European language education policy

Predmet ovog istraživanja je analiza postulata evropske obrazovne jezičke politike i rezultati koji se postižu primenom pojedinih njenih aspekata na planiranje nastave jezika struke/jezika za posebne namene. U radu su predstavljena teorijska i praktična saznanja iz primenjene lingvistike, teorije jezičke politike i planiranja i metodike nastave stranog jezika kao jezika struke/jezika za posebne namene. Pored toga, pravi se jasna razlika između jezika struke i jezika za posebne namene sa ciljem da se doprinese unapređenju terminološke preciznosti u ovoj oblasti primenjene lingvistike. Empirijski deo obuhvata akciono istraživanje bazirano na vlastitom iskustvu autorke u radu sa učenicima različitih struka i odnosi se na analizu efikasnosti primene preporuka Zajedničkog evropskog okvira za jezike u planiranju i nastavi jezika struke/jezika za posebne namene, uključivanja sociolingvističkih, interkulturnih i vanjezičkih elemenata u nastavu, kao i primene akcionog pristupa u nastavi jezika struke/jezika za posebne namene. U radu se prikazuje nekoliko inovativnih modela nastave francuskog jezika struke/jezika za posebne namene zasnovanih na ovim principima. Ispitanici su bili zaposleni u Ministarstvu pravde, pripadnici Ministarstva unutrašnjih poslova koji pohađaju specijalizovane tečajeve francuskog jezika u organizaciji Francuskog instituta u Beogradu i studenti Fakulteta bezbednosti Univerziteta u Beogradu koji pohađaju izbornu nastavu jezika struke u okviru Inovacionog centra Fakulteta bezbednosti. Pored toga, definisane su smernice za dalje unapređenje nastave jezika struke u našim visokoškolskim ustanovama a odnose se pre svega na učenje jezika struke od početnog nivoa, kreiranje programa nastave u skladu sa potrebama učenika i primenu adekvatnih metodoloških postupaka.The subject of this research work is an analysis of the premises of the European education policy, assessment of the results achieved through implementation of certain aspects of this policy and their impact on the planning of language teaching for vocational and specific purposes. The thesis presents theoretical and practical findings from the fields of applied linguistics, language policy and planning theory and foreign language teaching methodology for vocational and specific purpose language teaching. The thesis offers a clear distinction between the vocational language and specific purpose language, in order to achieve a higher level of terminological precision in this field of applied linguistics. The empirically based part of the thesis presents action based research results originating from the author’s personal experience in work with the students from a variety of vocational backgrounds and offers an assessment of the levels of efficiency achieved through practical implementation of the recommendations contained in the Common European Framework of Reference for Languages in the course of planning and realization of language teaching for vocational and specific purposes, inclusion of sociolinguistic, intercultural and extra linguistic elements in the teaching process, and implementation of the action based approach in language teaching for vocational and specific purposes. The thesis presents a number of innovative models of French language teaching for vocational and specific purposes based on these principles. The subjects were employees of the Ministry of Justice and Ministry of Interior Affairs who attended specialized language courses organized by the French Language Institute in Belgrade and students of the Faculty of Security of Belgrade University who attended elective language courses at the Innovation Centre of the Faculty of Security. Also, the thesis offers a set of guidelines for further improvement of the vocational language teaching at the institutions of higher education, focusing primarily on introduction of vocational language teaching in the early stages of language learning, starting from the beginner’s level, development of curricula that will meet the specific needs of the students and selection of appropriate teaching methods

Analysis of the correlation between socio-environmental factors and academic stress and mental health of students

Cilj: Mnogobrojni negativni faktori okruženja i psihosocijalni stresori, kao što su konstantni pritisak za uspehom, preopterećenost akademskim obavezama i nedostatak slobodnog vremena, a u današnje vreme i teška socijalno ekonomska situacija, doprinose nastanku sve češćih poremećaja psihofizičkog zdravlja univerzitetskih studenata, te je zdravlje ove populacije postalo fokus istraživanja poslednjih godina. Glavni ciljevi rada sastoje se u ispitivanju specifičnosti zdravstvenog stanja studenata Medicinskog fakulteta, Ekonomskog fakulteta i Fakulteta veterinarske medicine Univerziteta u Beogradu iz podataka sistematskih pregleda Zavoda za zdravstvenu zaštitu studenata Beograd sa posebnim osvrtom na mentalno zdravlje i analiza njihovog uspeha na studijama. Cilj rada je i procena uticaja socio-ekoloških faktora na psihofizičko zdravlje studenata tri ispitivana fakulteta, sa prospektivnim praćenjem uticaja ovih faktora kod studenata medicine. Kao cilj je navedena i analiza stanja psihičkog distresa, analiza rezultata pojave sindroma izgaranja (emocionalne iscrpljenosti, depersonalizacije i umanjenog samopostignuća) za studente sva tri ispitivana fakulteta, kao i analiza prevalencije faktora rizika za nastanak akademskog distresa i sindroma izgaranja na predkliničkim i kliničkim godinama studija Medicinskog fakulteta u Beogradu. Metodologija: Ovo istraživanje je dizajnirano kao kombinacija dve studije – studije preseka, koja predstavlja istraživanje prevalencije akademskog distresa i sindroma izgaranja kod studenata ispitivana tri fakulteta u Beogradu i prospektivne studije, kojom su obuhvaćeni studenti I i III godine Medicinskog fakulteta i tokom naredne II i IV godina studija sa ciljem da se ispitaju promene u rezultatima pojave akademskog distresa i sindroma izgaranja na predkliničkim i kliničkim godinama studija...Objective: Numerous negative environmental factors and psychosocial stressors, such as constant pressure to succeed, excessive academic obligations and lack of free time, and in the present time the difficult socioeconomic situation, contribute to the emergence of increasingly frequent mental and physical health disorders in university students, making the health of this population the focus of the recent research. The main objectives of this work include the analysis of the specifics of the health status of students of the School of Medicine, Faculty of Economics and the Faculty of Veterinary Medicine, University of Belgrade based on the data of physical examinations conducted at the Institute for Student Health Care Belgrade, with special emphasis on their mental health and academic achievement. The aim is to estimate the impact of socio-environmental factors on psychological and physical health of students of these three faculties, with the prospective monitoring of the impact these factors have on medical students. Another goal is the analysis of the mental distress, the analysis of the results of the occurrence of burnout syndrome (emotional exhaustion, depersonalization and reduced personal accomplishment) for students of all three faculties, as well as the analysis of the prevalence of risk factors for academic distress and burnout syndrome in preclinical and clinical years of studies at the School of Medicine in Belgrade. Methodology: This study was designed as a combination of two studies - cross section, which is a survey on the prevalence of academic distress and burnout syndrome among students studied at three universities in Belgrade and prospective studies, which included students first and third year of the School of Medicine, and over the next two and four years of study in order to examine the changes in the results of the occurrence of academic distress and burnout syndrome in preclinical and clinical years of study..