New evidence for prehistoric copper metallurgy in the vicinity of Bor

The last three years of archaeological investigations at the site Ru`ana in Banjsko Polje, in the immediate vicinity of Bor, have provided new evidence regarding the role of non-ferrous metallurgy in the economy of the prehistoric communities of north-eastern Serbia. The remains of metallurgical furnaces and a large amount of metallic slags at two neighbouring sites in the mentioned settlement reveal that locations with many installations for the thermal processing of copper ore existed in the Bronze Age. We believe, judging by the finds of material culture, that metallurgical activities in this area also continued into the Iron Age and, possibly, into the 4th century AD

Numerical Modelling of Y Joints of Trusses Made of Steel Hollow Sections

The use of welded structural hollow sections in civil engineering is relatively new. Constructing and dimensioning joints of steel trusses made of welded structural hollow sections requires a more specified approach, compared to traditional joints, achieved by gusset plates. Stress and local deformations at the contact between elements are non-linear and very complex. In this paper, the FEM modelling of the Y-joint was performed, accounting for the non-linear behaviour of steel. The ultimate bearing capacities of the joint were determined numerically, by applying different failure criteria. The results showed very good agreement with the experimental data

COMPARATIVE ANALYSIS OF USING DEGREE OF RIGIDITY AND ROTATIONAL STIFFNESS OF CONNECTIONS IN STRUCTURAL DESIGN

Using classical formulation of stiffness method, impact of semi-rigid connections on the stresses and strains can be analyzed by the degree of rigidity or by rotational stiffness of connections. In this paper, functional dependence between the degree of rigidity and rotational stiffness of connections is formulated and the comparative analysis of these two approaches in the analysis of semi-rigid connections behavior of members in real structures, is implemented

Cystitis in Children

Urinary tract infections in children are very common. However, their etiology, treatment, and prognosis are very different compared to adult patients. It is a field of interest that is covered by Pediatricians, Pediatric Nephrologists, Pediatric Surgeons, and Pediatric Urologists. There are of course different approaches with a common goal of urinary tract treatment, prevention, and in more serious cases kidney function preservation. This chapter offers a comprehensive review on the topic, with an attempt to offer impartial analysis of the practices widely accepted in treatment of urinary tract infections in childhood, with all the specific procedures typical for pediatric population

Izloženost endokrinim disruptorima kao prenatalni čimbenik rizika za kriptorhizam

This review describes the most recent data on the eff ects of endocrine disrupting compounds on reproductive tract development, as well as controversies in the fi eld. One of the most frequent conditions aff ected by endocrine disrupting compounds is cryptorchidism. Recent reports regarding the cause of this disorder continue to increase our understanding of this common and important problem. Endocrine disruptors are defi ned as exogenous substances with the ability to disrupt normal endocrine homeostasis and reproduction, and they include xenoestrogens, synthetic and natural hormones, phyto- and mycoestrogens, and other substances aff ecting endocrine signaling. Human exposure to endocrine disrupting chemicals is widespread. Epidemiological studies suggest associations between prenatal exposure to endocrine disrupting chemicals and numerous malformations of androgen dependent tissues. Animal models and epidemiological evidence link exposure to androgen disrupting chemicals with cryptorchidism, reduced sperm cell counts, increasing infertility, and testicular and prostate cancers. Since male sexual diff erentiation is androgen dependent, it is highly susceptible to endocrine disruptors. Whether the level of exposure contributes to the increasing prevalence of cryptorchidism is an ongoing debate. Further, there appears to be increased sensitivity to these agents during critical developmental periods when male diff erentiation is at its peak. Diff erences in the interpretation of the available studies underlie the disparate conclusions of scientifi c and regulatory body panels on the potential toxicological eff ects of endocrine disrupting chemicals at the current levels of human exposure. This review will highlight the evidence for endocrine disrupting chemicals that act through interference with the androgen receptor and lead to cryptorchidism.Ovaj pregledni članak donosi najnovije podatke o učincima endokrinih disruptora na razvoj reprodukcijskog sustava, kao i o proturječjima u ovom području. Kriptorhizam je jedno od najčešćih stanja na koja utječu endokrini disruptori. Novija izvješća o uzroku ovoga poremećaja sve više doprinose razumijevanju ovoga čestog i važnog problema. Endokrini disruptori defi niraju se kao egzogene tvari sposobne prekinuti normalnu endokrinu homeostazu i reprodukciju, a obuhvaćaju ksenoestrogene, sintetske i prirodne hormone, fi to- i mikoestrogene te druge tvari koje utječu na endokrine signale. Ljudi su uvelike izloženi takvim kemikalijama. Epidemiološke studije ukazuju na udruženost prenatalne izloženosti endokrinim disruptorima i brojnih malformacija tkiva ovisnih o androgenima. Životinjski modeli i epidemiološki dokazi povezuju izloženost androgenim disruptorima s kriptorhizmom, smanjenim brojem spermija, povećanjem neplodnosti te s rakom testisa i prostate. Muška seksualna diferencijacija ovisna je o androgenima, a time i veoma osjetljiva na endokrine disruptore. I dalje traju rasprave o tome doprinosi li razina izloženosti rastućoj učestalosti kriptorhizma. Nadalje, izgleda da je osjetljivost na ova sredstva povećana tijekom kritičnih razvojnih razdoblja obilježenih vršnom diferencijacijom kod muškog spola. Razlike u tumačenju dostupnih studija obilježavaju neujednačene zaključke znanstvenih i regulatornih panela o potencijalnim toksikološkim učincima endokrinih disruptora uz današnju razinu izloženosti ljudi. Ovaj pregledni rad pokazuje dokaze za endokrine disruptore koji djeluju kroz interferenciju s androgenim receptorima i dovode do kriptorhizma

Improving nonverbal communication in children with multiple disabilities, including visual impairment

Neverbalna komunikacija zauzima centralnu ulogu i ima neprocenjiv značaj u socijalnom životu čoveka. Predstavlja prirodni i prvi oblik socijalne interakcije. Najveći deo informacija koje doprinose usvajanju veština neverbal- ne komunikacije dete dobija putem vizuelnog opažanja i vizuelnog oponašanja modela. Nemogućnost ili smanjena mogućnost upotrebe vizuelnog senzornog ka- nala ometa neverbalnu komunikativnu razmenu. Učenicima sa oštećenjem vida koji imaju i kognitivne deficite je teško objasniti neverbalne signale bez konkretnog izvođenja neke radnje. Cilj istraživanja bio je utvrđivanje efekata programa za poboljšanje never- balne komunikacije kod višestruko ometene dece sa oštećenjem vida. Program je realizovan sa 10 višestruko ometenih učenika sa oštećenjem vida (eksperi- mentalna grupa) i 10 učenika sa intelektualnom ometenošću (kontrolna gru- pa). Nakon svake faze primene programa procenjivan je nivo dostignutih vešti- na pomoću Skale ispunjavanja cilja (Goal attainment scale). Inicijalna procena je pokazala da su višestruko ometena deca sa oštećenjem vida u odnosu na decu sa intelektualnom ometenošću imala prilično niži nivo veština neverbalne komunikacije. Iz merenja u merenje ova deca su sve više napredovala, tako da su na kraju skoro dostigla nivo kontrolne grupe.Nonverbal communication takes on a central role and has invaluable significance in the social life of a person. It presents the natural part and the first form of social interaction. The largest part of the information that contributes to the acquisition of nonverbal communication skills of a child is acquired through visual perception and visual imitation of the model. The inability or reduced ability to use the visual sensory channel impedes nonverbal communicative exchange. Students with visual impairments, who have cognitive deficits, are difficult to explain nonverbal signals without the specific performance of an action. The aim of the research was to determine the effects of the program for the improvement of nonverbal communication in visually impaired children with multiple disabilities. The program was conducted with 10 children with visual impairments and multiple disabilities (experimental group) and 10 students with intellectual disability (control group). After each stage of the application, the level of achievement was evaluated using the Goal attainment scale. The initial assessment showed that children with visual impairments and multiple disabilities, compared to children with intellectual disabilities, had a fairly lower level of nonverbal communication skills. From measurement to measurement, these children progressed more and more, so they almost reached the level of the control group in the end

Proučavanje raznovrsnosti bakterije Pseudomonas syringae poreklom sa različitih voćaka u Srbiji

Pseudomonas syringae is a widespread and economically important plant pathogen, one found on a number of hosts, including fruit trees, field crops, vegetables, and ornamental plants. This bacterium has been experimentally identified as a parasite of pear, apple, apricot, peach, cherry, sour cherry, plum, and raspberry. The present study was designed to establish differences between strains isolated from fruit trees in Serbia. The pathogenic and biochemical characteristics of isolates were studied. The BOX-PCR method was used to generate genomic fingerprints of Pseudomonas syringae isolates and to identify strains that were previously not distinguishable by other classification methods. Different Bacillus sp. strains were tested for in vitro inhibitory activity against Pseudononas syringae isolates. Bacillus sp. strains show inhibitory activity only against P. syringae isolates that originated from peach. The obtained results demonstrate that the population of the bacterium Pseudomonas syringae from the fruit trees in Serbia is very diverse.Pseudomonas syringae je široko rasprostranjena i ekonomski značajna fitopatogena bakterija, sa širokim krugom domaćina koji uključuje voćke, ratarske, povrtarske i ukrasne biljke. Pseudomonas syringae u Srbiji je eksperimentalno potvrđen kao parazit kruške, jabuke, kajsije, breskve, trešnje, višnje, šljive i maline. Cilj ove studije bio je da utvrdi postojanje eventualnih razlika između sojeva izolovanih sa različitih vrsta voćaka u Srbiji. Proučavane su patogene i biohemijske osobine sojeva. BOX-PCR je korišćen za dobijanje profila izolata Pseudomonas syringae u cilju identifikacije sojeva koji se ne mogu utvrditi drugim metodama. Različiti sojevi roda Bacillus su testirani u cilju utvrđivanja njihove in vitro inhibitorne aktivnosti. Sojevi roda Bacillus su pokazali inhibitornu aktivnost samo na P. syringae izolovanih sa breskve. Dobijeni rezultati pokazali suda je populacija bakterije Pseudomonas syringae poreklom sa voća u Srbiji vrlo raznovrsna

Optimization of the arsenic removal process from enargite based complex copper concentrate

Selective arsenic extraction from enargite based complex concentrate from Copper Mine in Bor (Serbia), using sodium hypochlorite as a leaching agent, was investigated in this paper. The aim was to assess the optimal conditions for the most efficient arsenic removal from the investigated concentrate, based on factorial design applied to experimentally obtained data. Five important factors with three factor levels were used as the input variables and experimentally obtained arsenic extraction yield was taken as the output variable. The first and the second final order model equations were obtained. It was found that the leaching temperature had the strongest effect on the arsenic extraction. The strongest positive interaction was between the sodium hypochlorite molar concentration and the stirring speed during extraction

Reke Srbije kao putevi invazije - istočni koridor invazije Reynoutria spp.

Increasing levels of invasion worldwide have been the source of concern for scientists, due to significant costs and efforts required for managing them. The knowledge of invasion pathways, both those of initial introduction and subsequent spread, is of key importance, since further increase in the number of pathways and vectors of invasion is predicted for the 21st century. At regional scales habitat type has proven to be a reliable predictor of the level of invasion, as certain habitat types (i.e. frequently disturbed, under strong anthropogenic influence) is characterized by high invasion levels. Riparian habitats, as hotspots of alien species diversity and primary sources of their spread, represent some of the most important invasion corridors, where water acts as an effective dispersal mechanism. Some invasive plant species, like Reynoutria spp. show a strong tendency to invade riparian habitats. Preliminary findings of field surveys aimed to assess the level of riparian invasion by Reynoutria spp. in Serbia suggest that some river basins are significantly affected by the presence of these invasive species. Bearing in mind the principal means of their propagation, further spread of Reynoutria spp. along the rivers in Serbia is to be expected over the following years.Stepen invazija koji je u porastu širom sveta zabrinjava naučnike, zbog značajnih troškova i napora koji su neophodni u njihovom kontrolisanju. Poznavanje puteva invazije, kako početnog unosa tako i naknadnog širenja vrsta, od ključnog je značaja, jer je u 21. veku prognoziran dalji porast broja puteva i vektora invazije. Na regionalnom nivou tip staništa se pokazao kao pouzdani pokazatelj nivoa invazije, jer određene tipove staništa (često remećena, pod snažnim antropogenim uticajem) karakteriše visok nivo invazije. Riparijalna staništa, kao centri diverziteta alohtonih vrsta i primarni izvor njihovog širenja, predstavljaju neke od najznačajnijih koridora invazije, u kojima voda deluje kao uspešan mehanizam disperzije. Neke invazivne vrste biljaka, poput Reynoutria spp. pokazuju snažnu tendenciju ka invaziji riparijalnih staništa. Preliminarni rezultati terenskih istraživanja koji su za cilj imali procenu nivoa invazije riparijalnih staništa vrstama roda Reynoutria u Srbiji ukazuju na to da su slivovi nekih reka pod značajnim uticajem prisustva ovih invazivnih vrsta. Imajući u vidu osnovni vid njihove propagacije, dalje širenje Reynoutria spp. duž reka u Srbiji može se očekivati tokom narednih godina

Investigation of copper(I) sulphide leaching in oxidative hydrochloric acid solution

Present work is focused on the copper (I) sulphide leaching with sodium chloride in hydrochloric acid solution and with introduction of gaseous oxygen. Chemical reactions of leaching and their thermodynamic probabilities are predicted based on the literature data and products which were formed during the process and the overall leaching reaction was defined. The influence of temperature and time on the leaching degree of copper was experimentally determined. The quantity of dissolved copper increases with the increase of both investigated parameters. Elemental sulphur was formed as the main leaching product, precipitated at the particle surfaces and chloride ions have a role to disrupt the creation of this passive layer