220 research outputs found
Stark broadening data for spectral lines of rare-earth elements: Nb III
The electron-impact widths for 15 doubly charged Nb ion lines have been
theoretically determined by using the modified semiempirical method. Using the
obtained results, we considered the influence of the electron-impact mechanism
on line shapes in spectra of chemically peculiar stars and white dwarfs.Comment: 10 pages, 2 figures, 1 table, accepted in Advances in Space Researc
Primena sulfidnih minerala kao potenciometrijskih senzora za acido-bazne titracije u nekim nevodenim rastvaračima
Imobilizacija perjodatno oksidovane invertaze adsorpcijom na sepiolitu
Periodate oxidized invertase was immobilized by adsorption on sepiolite. The obtained immobilized enzyme was more resistant to washing out by concentrated salt solution. and had an eight times higher half-life at 60 degreesC than adsorbed native invertase. In packed bed reactor 50%, conversion of 500 g/dm(3) sucrose at 40 degreesC and a flow rate of 1 bv/h was achieved. The specific productivity of the immobilized invertase was 0.187 kg/dm(3)/h.Perjodatno oksidovana invertaza je imobilizovana adsorpcijom na sepiolitu. Dobijeni imobilizovani enzim je bio rezistentniji na ispiranje koncentrovanim rastvorima soli i imao je osam puta veći poluživot na 60 ºC od adsorbovane nativne invertaze. U protočnom cevastom reaktoru dobili smo 50 % konverziju rastvora saharoze koncentracije 500 g/dm3 na 40 ºC i pri protoku od 1 bv/h. Specifična produktivnost imobilizovane invertaze je bila 0,187 kg/dm3/h
Late Vinča culture settlement at Crkvine in Stubline: Household organization and urbanization in the Late Vinča culture period
Poznovinčansko naselje na lokalitetu Crkvine nalazi se oko 40 km jugozapadno od Beograda (Srbija), u blizini sela Stubline, opština Obrenovac. Situirano je na blagom uzvišenju, sa severa i juga omeđenom potocima koji se spajaju ispod njegovog jugoistočnog kraja, i zauzima površinu od oko 16 ha (sl. 1). Tokom 2007. i 2008. godine obavljena su geomagnetna istraživa na površini od 32400 m2 (25% ukupne površine poznovinčanskog naselja), na samoj zapadnoj periferiji naselja. Analiza dobijenih rezultati ukazuje na postojanje oko 100 kuća izgrađenih u redovima oko većih praznih površina, a konstatovani su i rovovi koji su sa severne i južne strane okruživali naselje (sl. 3). U jesen 2008. godine Zavod za zaštitu spomenika kulture grada Beograda i Muzej grada Beograda, preduzeli su arheološka iskopavanja sa ciljem provere značenja određenih vrednosti geomagnetnih anomalija. Sonda 06/2008, dimenzija 8 h 1 m postavljena je na mestu gde je geomagnetnom prospekcijom konstatovana anomalija čije vrednosti su iznosile 10 nT. Iskopom vršenim samo do površine obrušenog zidnog lepa konstatovano je postojanje objekta (kuća 2/2008) koji nije goreo visokim intenzitetom. U sondi 05/2008, 9 h 9 m, pozicioniranoj iznad anomalije sa vrednostima između 10 nT i 25 nT, otkriven je stambeni objekat (kuća 1/2008), čija je osnova bila skoro u celosti očuvana. Orijentacija istraženog objekta, sever-severoistok - jugjugoistok (sl. 4), podudara se sa orijentacijama većine ostalih objekata konstatovanih geomagnetnim snimanjem. Sam način gradnje, kao i prostorna organizacija kuće, u okvirima su očekivanog za ovaj period. Ukupna istražena dužina kuće iznosi 9.15 m, dok širina varira između 4.70 i 4.85 m (sl. 5). Osim pokretnih nalaza uobičajenih za ovaj period (Vinča D) pronađeni si i fiksini delovi pokućstva: peć sa kaltotom u severoistočnom uglu kuće (sl. 8) i podnica uništene peći u jugozapadnom delu, koje takođe pripadaju uobičajenim nalazima Novinu donose konstrukcija žrvnja, izgrađenog od gline u obliku korita sa izdignutom platformom na sredini na čijem vrhu je bio utisnut ravan kamen (sl. 14) i glineni recipijent (žrtvenik?) koji je otkriven u severozapadnom uglu kuće, pored koga su se nalazili 'pogača' od gline prečnika 20 cm, posuda sa izlivnikom i tzv. 'omfalos' (sl. 12 i 15). Posebno treba istaći nalaz kompozicije od ukupno 46 figurina (38 pronađenih ispred samog otvora peći, kraj njenog jugozapadnog ugla, i još osam identičnih u neposrednoj blizini), kao i njima pripadajućih 11 minijaturnih modela alatki od gline (sl. 10 i 11). Ovaj izuzetni nalaz ukazuje barem na dve stvari: transponovanje određenog sistema razmišljanja ili verovanja, sa nivoa zajednice na nivo kultne radnje ili igre, prethodio je izradi kompozicije; postojanje 45 oblikom identičnih figurina i jedne veće i razuđenije (nalazila se u sredini grupe od 9 manjih figurina) ukazuje na mogućnost postojanja jasne hijerarhije u zajednici ili religijskom sistemu. Dosadašnja geomagnetna istraživanja dozvoljavaju pretpostavku o izvesnoj urbanizaciji ovoga naselja. Na ovome lokalitetu uočeno je da postoji više grupa kuća koje su skoncentrisane oko većih slobodnih površina (trgova?). Evidentno ponavljanje ovakvih struktura ukazuje na jasno planiranje, koje može, ali i ne mora, da bude uslovljeno određenim socijalnim faktorima. Upravo te slobodne površine možda ukazuju i na postojanje prostora na kojima su mogle biti obavljane neke zajedničke aktivnosti (profanog ili sakralnog karaktera), ali i koje su mogle služiti kao mesta svakodnevnog okupljanja, budući da je prostor između samih kuća isuviše mali. Na rastojanju od 15 km od poznovinčanskog naselja Crkvine kod Stublina nalazi se još 10 lokaliteta sa poznovinčanskim horizontom kao poslednjom fazom življenja na njima (sl. 17). Stepen njihove istraženosti ne dozvoljava precizno hronološko opredeljenje prekida življenja na svim lokalitetima, ali je neosporno da se na više njih u određenim periodima istovremeno živelo. Imajući u vidu dosadašnja razmatranja o gustini naseljenosti u vreme poznog neolita, prisustvo više velikih naselja u međurečju Save, Tamnave i Kolubare, na relativno maloj površini, otvara i niz pitanja o ustrojstvu koje je omogućavalo njihovu koegzistenciju.The site Crkvine is situated in the vicinity of the village Stubline in the borough of Obrenovac around 40 km to the southwest of Belgrade (Serbia). In the first section of this work we present the comprehensive report about the investigations carried out so far. The geomagnetic prospection undertaken from 2006 to 2008 covered an area of 32,400 square meters and the obtained results indicate the existence of around 100 houses built in rows around the rather large open areas as well as the trenches surrounding the settlement. The investigations of the house 1/2008 dating from the Vinča culture D-2 period yielded in addition to the data concerning its interior organization also a unique find of the group of 46 figurines with 11 models of miniature tools. In the second section of this work we discuss the prospects, which future investigations of this site and its environment could provide concerning the study of the social organization in the very end of the Vinča culture
Stark broadening of B IV lines for astrophysical and laboratory plasma research
Stark broadening parameters for 36 multiplets of B IV have been calculated
using the semi-classical perturbation formalism. Obtained results have been
used to investigate the regularities within spectral series and temperature
dependence.Comment: 8 pages, 6 figures, 1 table, in press in Advances in Space Researc
Hydro-meteorological data quality assurance and improvement
Advances in measurement equipment and data transfer enabled easy and economic automatic monitoring of various hydro-meteorological variables. The main characteristic of such automatic monitoring systems is that they do not rely on human activities, but only on electronic devices. Even if those electronic devices are of highest quality and accuracy, and properly tuned to specific problem, the reliability of measured values relyieson many other factors and unexpected or undesired occurrences, like modification of measurement micro location, power supply shortages or surges, etc. The sampled and acquired data values have to be additionally checked, validated and sometimes improved or cleared before further use. This paper presents an innovative approach to data validation and improvement through the framework generally applicable to all hydrological data acquisition systems. The proposed framework can incorporate any number of validation methods and can be easily customized according to the characteristics of every single measured variable. The framework allows for the self-adjustment and feedback to support self-learning of used validation methods, same as expert-controlled learning and supervision. After data validation, for low-scored data, its value quality can be improved if redundant data exist, so framework has the data reconstruction module. By applying different interpolation techniques or using redundant data value the new data is created same as accompanying metadata with the reconstruction history. After data reconstruction, the framework supports the data adjustment, the post-processing phase where the data is adjusted for the specific needs of each user. Every validated and sometimes improved data value is accompanied with a meta-data that holds its validation grade as a quality indicator for further use.
SWAT-based runoff modeling in complex catchment areas: Theoretical background and numerical procedures
This paper shows the structure of the SWAT-based model used in modeling of the 'rainfallrunoff' process. The SWAT model is hydro-dynamic and physically-based model for application in complex and large basins. Model inputs are as follows: rainfall, air temperature, soil characteristics, topography, vegetation, hydrogeology and other relevant physical parameters. The model is based on five linear reservoirs as follows: reservoir of the vegetation cover, snow accumulation and melting, surface reservoir, underground reservoir and surface runoff reservoir. The model uses GIS tools for preprocessing and post-processing. The basic modeling unit is the hydrologic response unit (HRU), defined as the network of elementary hydrologic areas with the selected discretization, measure of which is dependent upon the desired accuracy, as well as upon data accuracy. The total runoff on the exit profile of the catchment is computed by convolution of the sum of runoffs (surface and base runoffs). The model can be applied at the daily and hourly level of discretization and used for multiannual simulations. Illustration of operation of the SWAT based model will be presented on a selected part of the River Drina basin (with the total area of around 20.000 km2).
Acute diarrhea in children
© 2015, Serbia Medical Society. All rights reserved. Acute diarrhea (AD) is the most frequent gastroenterological disorder, and the main cause of dehydration in childhood. It is manifested by a sudden occurrence of three or more watery or loose stools per day lasting for seven to 10 days, 14 days at most. It mainly occurs in children until five years of age and particularly in neonates in the second half-year and children until the age of three years. Its primary causes are gastrointestinal infections, viral and bacterial, and more rarely alimentary intoxications and other factors. As dehydration and negative nutritive balance are the main complications of AD, it is clear that the compensation of lost body fluids and adequate diet form the basis of the child’s treatment. Other therapeutic measures, except antipyretics in high febrility, antiparasitic drugs for intestinal lambliasis, anti-amebiasis and probiotics are rarely necessary. This primarily regards uncritical use of antibiotics and intestinal antiseptics in the therapy of bacterial diarrhea. The use of antiemetics, antidiarrhetics and spasmolytics is unnecessary and potentially risky, so that it is not recommended for children with AD
DEM-based GIS algorithms for automatic creation of hydrological models data
In this paper the authors discuss the Digital Elevation Model (DEM) based GIS algorithms, applicable for automatic creation of input data needed by hydrological models. The expected source of DEM data are standard digital data sets that a modeler can purchase from the official data sources. The DEM has to be cleared from errors and prepared for standard hydrology usage as the depression less version, or a version of DEM where only small depressions are filled-in, while larger depressions are extracted as separate objects. The slopes and aspects are calculated from such DEM. The flow accumulation image is created using slopes and aspects and using information about large ponds. From flow accumulation image the surface drainage network is extracted with user-specified density. Based on slopes and aspects, the catchment is delineated into subcatchments, the areas drained by each river segment. Finally, the model-specific parameters like length of flow segment along the terrain and along the river to the subcatchment outlet, slope of those segments, subcatchment shape factor, or subcatchments mean or weighted slope are calculated. Paper explains the used algorithms and emphasizes the problems one can encounter during the usage of DEM data using examples from River Drina catchment. Finally, the authors comment on overall usability of presented GIS algorithms, especially if purchased data are of low quality.
Fractional Calculus Model of Electrical Impedance Applied to Human Skin
Fractional calculus is a mathematical approach dealing with derivatives and integrals of arbitrary and complex orders. Therefore, it adds a new dimension to understand and describe basic nature and behavior of complex systems in an improved way. Here we use the fractional calculus for modeling electrical properties of biological systems. We derived a new class of generalized models for electrical impedance and applied them to human skin by experimental data fitting. The primary model introduces new generalizations of: 1) Weyl fractional derivative operator, 2) Cole equation, and 3) Constant Phase Element (CPE). These generalizations were described by the novel equation which presented parameter (beta) related to remnant memory and corrected four essential parameters (R-0, R-infinity, alpha, tau(alpha)). We further generalized single generalized element by introducing specific partial sum of Maclaurin series determined by parameters (beta(*), gamma,delta ...). We defined individual primary model elements and their serial combination models by the appropriate equations and electrical schemes. Cole equation is a special case of our generalized class of models for beta* = gamma = delta = ... = 0. Previous bioimpedance data analyses of living systems using basic Cole and serial Cole models show significant imprecisions. Our new class of models considerably improves the quality of fitting, evaluated by mean square errors, for bioimpedance data obtained from human skin. Our models with new parameters presented in specific partial sum of Maclaurin series also extend representation, understanding and description of complex systems electrical properties in terms of remnant memory effects
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