454 research outputs found
Superfluid drag of two-species Bose-Einstein condensates in optical lattices
We study two-species Bose-Einstein condensates in quasi two-dimensional
optical lattices of varying geometry and potential depth. Based on the
numerically exact Bloch and Wannier functions obtained using the plane-wave
expansion method, we quantify the drag (entrainment coupling) between the
condensate components. This drag originates from the (short range)
inter-species interaction and increases with the kinetic energy. As a result of
the interplay between interaction and kinetic energy effects, the
superfluid-drag coefficient shows a non-monotonic dependence on the lattice
depth. To make contact with future experiments, we quantitatively investigate
the drag for mass ratios corresponding to relevant atomic species.Comment: 6 pages, 4 figures. Accepted in its original form but minor changes
have been don
Thermal mass impact on energy performance of a low, medium and heavy mass building in Belgrade
Heavy mass materials used in building structures and architecture can significantly affect building energy performance and occupant comfort. The purpose of this study was to investigate if thermal mass can improve the internal environment of a building, resulting in lower energy requirements from the mechanical systems. The study was focused on passive building energy performance and compared annual space heating and cooling energy requirements for an office building in Belgrade with several different applications of thermal mass. A three-dimensional building model was generated to represent a typical office building. Building shape, orientation, glazing to wall ratio, envelope insulation thickness, and indoor design conditions were held constant while location and thickness of building mass (concrete) was varied between cases in a series of energy simulations. The results were compared and discussed in terms of the building space heating and cooling energy and demand affected by thermal mass. The simulation results indicated that with addition of thermal mass to the building envelope and structure: 100% of all simulated cases experienced reduced annual space heating energy requirements, 67% of all simulated cases experienced reduced annual space cooling energy requirements, 83% of all simulated cases experienced reduced peak space heating demand and 50% of all simulated cases experienced reduced peak space cooling demand. The study demonstrated that there exists a potential for reducing space heating and cooling energy requirements with heavy mass construction in the analyzed climate region (Belgrade, Serbia)
Risk Factors for Neonatal Sepsis and Method for Reduction of Blood Culture Contamination
Background: False-positive blood cultures findings may lead to a falsely increased morbidity and increased hospital costs.Method: The survey was conducted as retrospective - prospective study and included 239 preterm infants (born before 37 weeks of gestation) who were treated in Neonatal Intensive Care Unit (NICU) in Institute for Child and Youth Health Care of Vojvodina during one year (January 1st, 2012 to December 31st, 2012). The retrospective part of the study focused on examination of incidence of neonatal sepsis and determination of risk factors. In the prospective part of the study infants were sub-divided into two groups: Group 1- infants hospitalized in NICU during the first 6 months of the study; blood cultures were taken by the āāclean techniqueāā and checklists for this procedure were not taken. Group 2- neonates hospitalized in NICU during last 6 months of the study; blood cultures were taken by āāsterile techniqueāā and checklists for this procedure were taken.Results: The main risk factors for sepsis were prelabor rupture of membranes, low gestational age, low birth weight, mechanical ventilation, umbilical venous catheter placement, and abdominal drainage. Staphylococcus aureus and coagulase negative Staphylococcus were the most frequently isolated microorganisms in false-positive blood samples.Conclusions: Education of employees, use of checklists and sterile sets for blood sampling, permanent control of false positive blood cultures, as well as regular and routine monthly reports are crucial for successful reduction of contamination rates
Polymers Based on Renewable Raw Materials ā Part II
A short review of biopolymers based on starch (starch derivatives, thermoplastic starch), lignin and hemicelluloses, chitin (chitosan) and products obtained by degradation of starch and other polysaccharides and sugars (poly(lactic acid), poly(hydroxyalkanoates)), as well as some of their basic properties and application area, are given in this part. The problem of environmental and economic feasibility of biopolymers based on renewable raw materials and their competitiveness with polymers based on fossil raw materials is discussed. Also pointed out are the problems that appear due to the increasing use of agricultural land for the production of raw materials for the chemical industry and energy, instead for the production of food for humans and animals. The optimistic assessments of experts considering the development perspectives of biopolymers based on renewable raw materials in the next ten years have also been pointed out.At the end of the paper, the success of a team of researchers gathered around the experts from the company Bayer is indicated. They were the first in the world to develop a catalyst by which they managed to effectively activate CO - and incorporate it into polyols, used for the synthesis of polyurethanes in semi-industrial scale. By applying this process, for the first time a pollutant will be used as a basic raw material for the synthesis of organic compounds, which will have significant consequences on the development of the chemical industry, and therefore the production of polymers
Controlling qubit arrays with anisotropic XXZ Heisenberg interaction by acting on a single qubit
We investigate anisotropic XXZ Heisenberg spin-1/2 chains with control fields acting on one of the end spins, with the aim of exploring local quantum control in arrays of interacting qubits. In this work, which uses a recent Lie-algebraic result on the local controllability of spin chains with "always-onā interactions, we determine piecewise-constant control pulses corresponding to optimal fidelities for quantum gates such as spin-flip (NOT), controlled-NOT (CNOT), and square-root-of-SWAP (). We find the minimal times for realizing different gates depending on the anisotropy parameter Ī of the model, showing that the shortest among these gate times are achieved for particular values of Ī larger than unity. To study the influence of possible imperfections in anticipated experimental realizations of qubit arrays, we analyze the robustness of the obtained results for the gate fidelities to random variations in the control-field amplitudes and finite rise time of the pulses. Finally, we discuss the implications of our study for superconducting charge-qubit array
Rat duodenal motility in vitro: Prokinetic effects of DL-homocysteine thiolactone and modulation of nitric oxide mediated inhibition
Homocysteine is a significant but modifiable risk factor for vascular
diseases. As gastrointestinal smooth musculature is similar to blood vessel
muscles, we investigated how elevated homocysteine levels affect nitric
oxide-mediated neurotransmission in the gut. There is accumulated evidence
that a dysfunction of NO neurons in the myenteric plexus may cause various
diseases in the gastrointestinal tract such as achalasia, diabetic
gastroparesis and infantile hypertrophic pyloric stenosis. In the present
study, we aimed to assess the effects of homocysteine on NO-mediated
responses in vitro, and to examine the effects of DL-homocysteine thiolactone
on the spontaneous motility of rat duodenum and nitrergic neurotransmission.
DL-homocysteine thiolactone concentration of 10 Ī¼mol/L leads to the immediate
increase in tone, amplitude and frequency of spontaneous movements in
isolated rat duodenum. L-NAME (30 Ī¼mol/L) leads to an increase in basal tone,
amplitude and frequency of spontaneous contractions. The relaxations induced
by EFS were significantly reduced in duodenal segments incubated in
DL-homocysteine thiolactone compared with the control group. EFS-induced
relaxations were inhibited by L-NAME in both experimental and control groups.
These results suggest that a high level of homocysteine causes an important
impairment of non-adrenergic non-cholinergic innervation of the rat duodenum.
[Projekat Ministarstva nauke Republike Srbije, br. 175043
Implikacije koncepta fer vrednosti na pouzdanost finansijskih izveŔtaja
The primary task of financial reporting is creation, presentation and disclosure of high-quality and reliable financial reports, which represent a large informational potential for investors, creditors, managers, financial analysts and other financial reports` beneficiaries. The reliability of financial reports, as a result of joint qualitative characteristics, is one of the preconditions for the stability of the financial system and a determinant of the investorās security. Since the financial statements can be considered expedient only if they represent a credible and valid informational base, the aim of this paper is to demonstrate that the concept of fair value has significant implications for the reliability of financial reports, that is their internal use, for the purposes of determining a taxable income, distribution of profit, management decisions, as well as their external use, which implies informing investors, government authorities, agencies, tax authorities, banks, financial institutions and the rest of the public. For the purpose of achieving above mentioned objective, this doctoral thesis encompasses a theoretical research based on a contemporary literature available in the domain of financial reporting and empirical research based on a modern financial reporting regulatory framework and its application. The empirical studies were based on the application of the comparative method used to confirm the differences in the value of assets, with application of the fair value concept in relation to the concept of historical cost, together with the application of case studies method during the analysis of implementation of various balance sheet items, as well as analysis - synthesis methods applied to fully understand the impact of the fair value on the financial position and performances of the entity. The research results obtained during the preparation of the doctoral thesis, formulated using the method of induction and deduction, as well as the content analysis method, indicate the existence of obvious and significant implications of the fair value concept on the reliability of financial reporting, both in terms of stable economic conditions, and in the circumstances of financial crisis, and that the application of the fair value concept contributes to achieving the primary goal of financial reporting ā that is providing a trustworthy insight into the financial situation and the contributory position of the reporting entity
Taxonomic-faunistical study of butterflies and moths (Insecta : Lepidoptera) of mt. FruŔka Gora
U studiji je dat prikaz jedanaestogodiŔnjih istraţivanja insekata iz reda Lepidoptera na FruŔkoj gori. Registrovane su 934 vrste leptira i moljaca. Za 382 vrste
Lepidoptera ili 40,89% od ukupnog broja vrsta izvrŔena je taksonomska verifikacija
analizom hitinskih armatura genitalnih aparata. U periodu od 2001. do 2011. godine
sakupljani su leptiri i moljci uglavnom uz pomoÄ svetlosne klopke (Å£ivine sijalice
TEÅ¢ WTF od 250 W, āPhilips Mlā od 100, 160, 250 i 400 W i petromaks lampe od
400 W), iza koje je postavljeno belo pamuÄno platno. 934 zabeleÅ£ene vrste su svrstane
u 22 superfamilije, 47 familija i 564 rodova. Broj od 934 vrste Lepidoptera predstavlja
u odnosu na evropsku faunu leptira (8478 vrsta) 11,01%. Sve vrste leptira i moljaca
FruÅ”ke gore svrstane su u 7 zoogeografskih kategorija. PreovlaÄuju evroazijske vrste
(449 vrsta ili 48,07% od ukupnog broja vrsta). Evropskih vrsta je 236 (25,27% od
ukupnog broja vrsta). Mediteransko-azijski elementi su zastupljeni sa 162 vrste ili
17,34% od ukupnog broja vrsta. HolarktiÄki elementi zastupljeni su sa 44 vrste ili sa
4,71% od ukupnog broja vrsta, a palearktiÄki sa 25 vrsta ili 2,68% od ukupnog broja
vrsta. Paleotropsko-suptropski elementi zastupljeni su sa 10 vrsta ili sa 1,07% od
ukupnog broja vrsta. Kosmopolitskih vrsta je 8 vrsta ili 0,86% od ukupnog broja
vrsta.
Sve evidentirane vrste u ovoj studiji grupisane su u pet skupova: mali moljci,
veliki moljci, dnevni leptiri, zemljomerke i sovice. Ukupno 287 vrsta malih moljaca
svrstano je u 16 superfamilija i 31 familiju. ViŔe od 5% vrsta malih moljaca Evrope
(5,16%) je zastupljeno na FruŔkoj gori. Veliki moljci (Lasiocampidae, Saturniidae,
Sphingidae, Drepanidae, Notodontidae, Lymantriidae i Arctiidae) su zastupljeni na
FruÅ”koj gori sa 77 vrsta . ViÅ”e od Äetvrtine vrsta velikih moljaca Evrope (27,5%) je
zastupljeno na FruŔkoj gori. Dnevni leptiri (Hesperiidae, Papilionidae, Pieridae,
Lycaenidae i Nymphalidae) su zastupljeni na FruŔkoj gori sa 115 vrsta. ViŔe od
Äetvrtine vrsta dnevnih leptira Evrope (26,13%) je zastupljeno na FruÅ”koj gori.
Zemljomerke su zastupljene na FruŔkoj gori sa 187 vrsta. Oko petine vrsta
zemljomerki Evrope (20,43%) je zastupljeno na FruŔkoj gori. Sovice (Noctuidae,
Pantheidae, Nolidae) su zastupljene na FruŔkoj gori sa 268 vrsta. ViŔe od petine vrsta
sovica Evrope (20,87%) je zastupljeno na FruŔkoj gori. Najbrojnija je grupa malih
moljaca sa 287 zabeleÅ£enih vrsta ili sa 30,73% od ukupnog broja utvrÄenih vrsta. Zatim sledi grupa sovica sa 268 zabeleÅ£enih vrsta ili 28,69% od ukupnog broja
utvrÄenih vrsta. Na treÄem mestu po zastupljenosti nalazi se grupa zemljomerki sa
187 zabeleÅ£enih vrsta ili sa 20,02% od ukupnog broja utvrÄenih vrsta. Slede dnevni
leptiri (sa 115 vrsta ili 12,31% od ukupnog broja vrsta) i veliki moljci (sa 77 vrsta ili
8,24% od ukupnog broja vrsta).
Na FruŔkoj gori je zabeleţeno 129 vrsta Lepidoptera (13,80% od ukupnog
broja vrsta) koje mogu naneti Å”tetu liÅ”Äarskom i Äetinarskom drveÄu. IstraÅ£ivanjima na
FruŔkoj gori identifikovana je 61 vrsta Lepidoptera iz grupe migratornih vrsta, tj.
selica. Sezonskih selica prvog reda ima 7 vrsta, sezonskih selica drugog reda 1 vrsta,
selica iseljenika (lokalnih selaca prvog i drugog reda) 36 vrsta, selica raseljenika
(povremenih selaca) 10 vrsta, selica raseljenika (vrsta koje proŔiruju svoj areal) 2
vrste, dok moguÄih selica ima 5 vrsta.
U odnosu na zabeleţeni broj od 934 vrste leptira, procenjuje se da je
poznato svega oko jedne treÄine vrsta koje bi se mogle otkriti na FruÅ”koj gori.
PronaÄene su 133 nove vrste iz reda Lepidoptera za faunu Srbije.
Prvi put u Srbiji, ali i u zemljama u sastavu bivŔe SFRJ je kao prilog
poznavanju faune Lepidoptera u ovoj studiji dat detaljan prikaz hitinskih armatura
genitalnih aparata sa opredeljujuÄim taksonomskim karakteristikama za 250 vrsta
(26,76% od ukupnog broja vrsta) uglavnom iz grupe malih moljaca i za nekoliko
izdvojenih taksona ostalih grupa. Dat je uporedni prikaz brojnosti vrsta po familijama
i superfamilijama za FruÅ”ku goru, TimoÄku krajinu, Evropu, Rumuniju, rumunski
Banat i MaÄarsku.
Lepidoptera su veoma slabo istraÅ£eni na pojedinim podruÄjima FruÅ”ke
gore. Ovo se prvenstveno odnosi na podruÄje juÅ£no od Dunava oko NeÅ”tina, Suseka,
BanoÅ”tora i ÄereviÄa, deo od Sremskih Karlovaca do Petrovaradina i Äortanovaca, od
KruŔedola i Neradina do Iriga sa juţne strane FruŔke gore i od Vrdnika do Leţimira sa
jugozapadne strane (izuzimajuÄi podruÄje oko grgurevaÄkog lovaÄkog doma, selo
Grgurevci). Neophodno je da se faunistiÄka i ekoloÅ”ka istraÅ£ivanja nastave. Veliki
broj lokaliteta je nedovoljno istraţen, na pojedinim mikrolokalitetima istraţivanja nisu
ni otpoÄela, a potencijalno su na njima se mogu naÄi zanimljivi nalazi.This thesis presents results of an eleven-year research on insects belonging
from order Lepidoptera on Mt. FruŔka Gora. Total of 934 species were recorded. For
382 species Lepidoptera, or 40.89% of the total number of species, a taxonomic
verification has been performed by the analysis of chitinous armatures of genital
apparatus. In the 2001-2011 period, the specimens were collected mostly by light trap
(mercury bulb TEÅ¢ WTF of 250W, āPhilips Mlā of 100, 160, 250 and 400W, and
Petromax lamp of 400W), with a white cotton sheet propped in behind. 934 recorded
species of Lepidoptera belong to 22 superfamilies, 47 families and 564 genera. The
number of 934 species represents 11,01% of European fauna of Lepidoptera (8,478
species). The Lepidoptera species from Mt. FruŔka Gora are classified into seven
zoogeographical categories. Eurasian species are prevailing (449 species or 48.07% of
the total number of species). We recorded 236 European species (25.27% of the total
number of species) and 162 Mediterranean-Asian species (17.34% of the total number
of species). Holarctic elements are represented by 44 species (4.71% of the total
number of species), Palearctic elements by 25 species (2.68% of the total number of
species), while Paleotropical-subtropical elements are represented by 10 species
(1.07% of the total number of species). Finally, cosmopolitan elements are
represented by eight species (0.86% of the total number of species).
Within the research, all registered species were classified into five groups:
Microlepidoptera (micromoths), macromoths, butterflies, geometrid moths and owlet
moths. 287 species of micromoths are classified into 16 superfamilies and 31 families.
More than 5% of European species of micromoths (5.16%) are present on Mt. FruŔka
Gora. Macromoths (Lasiocampidae, Saturniidae, Sphingidae, Drepanidae,
Notodontidae, Lymantriidae and Arctiidae) are represented on Mt. FruŔka Gora with
77 species. More than one quarter of European species of macromoths (27.5%) are
recorded on Mt. FruŔka Gora. Butterflies (Hesperiidae, Papilionidae, Pieridae,
Lycaenidae and Nymphalidae) are represented on Mt. FruŔka Gora with 115 species,
which is more than a quarter of the butterfly species of Europe (26.13%). Geometrid
moths are represented by 187 species on Mt. FruŔka Gora, which is about one fifth of
European species of Geometridae (20.43%). Owlet moths (Noctuidae, Pantheidae and Nolidae) are represented on Mt. FruŔka Gora by 268 species, which is more than a
fifth of the European owlet moth species (20.87%). The micromoths are the most
numerous group with 287 recorded species, or 30.73% of the total number of species
recorded on Mt. FruŔka Gora. They are followed by the group of owlet moths with
268 recorded species (28.69% of the total number of species), geometrid moths with
187 recorded species (20.02% of the total number of species), butterflies (with 115
species or 12.31% of the total number of species), and macromoths (with 77 species
or 8.24% of the total number of species).
Of all Lepidoptera species recorded in Mt. FruŔka Gora, 129 (or 13.80% of the
total number of species) may be harmful for deciduous and coniferous trees. Research
also revealed 61 species of Lepidoptera belonging to the group of migratory species.
Seven species are first-order seasonal migratory species (eumigrators), one seasonal
species is second-order migratory species (paramigrator), and 36 species are
emigrants (first- and second-order local migrants). Finally, among the dismigrators
there are two invasive species that expand their areas and five species that are
possibly migratory.
Regarding the recorded number of 934 species of Lepidoptera, it is estimated
that this is just one third of the species that might exist on Mt. FruŔka Gora and the
rest could be recorded in the future. From Lepidoptera species recorded, 133 are new
for the fauna of Serbia.
For the first time in Serbia, but also in other former Yugoslav countries, a
detailed analysis of chitinous armatures of genital apparatus with presenting specific
taxonomic characteristics for 250 species (26.76% of the total number of recorded
species), mostly for micromoths and some selected taxa. A comparative overview is
given of species population number within families and superfamilies in investigated
FruÅ”ka Gora area, as well as for TimoÄka Krajina, Europe, Romania, Romanian
Banat, and Hungary.
The order Lepidoptera is not sufficiently investigated in some areas of Mt.
FruŔka Gora. This primarily refers to the area south of the Danube River around
NeÅ”tin, Susek, BanoÅ”tor, and ÄereviÄ, to the part between Sremski Karlovci,
Petrovaradin and Äortanovci, from KruÅ”edol and Neradin to Irig on the south slope of
Mt. FruŔka Gora, and from Vrdnik to Leţimir on the southwest slope (except the area
around hunterās house in the village of Grgurevci). Therefore, it is necessary to
continue further faunistic and ecological research. A large number of localities are not
explored enough, while at some microlocalities investigations have not even started, although they could be very interesting with possible new findings
Nove klase funkcija za sintezu dvokanalne hibridne banke filtara
This PhD discusses the research related to the approximation and implementation of the twochannel
hybrid filter banks. Special attention is paid to the analogue part, i.e. analysis part of
the hybrid filter banks.
Two approximations of the filter bank pair for analysis have been proposed. The first approximation
of the transfer function of the low-pass filter is based on the simple adaptation
of the orthogonal Jacobi polynomials in order to obtain the Pseudo-Jacobian polynomials. In
relation to other known approximations, the Pseudo-Jacobian polynomial one has two prime
parameters, which can adjust the characteristics of the filter in wide ranges. This approximation
can be successfully applied for the realization of a complementary bank of filters.
It is known that recursive double-complementary digital filter banks can be implemented
with all-pass filters, and research has shown that double-complementary filter banks can also
be realized in the analogue domain. The realization of the proposed filter bank has been done
in two steps. In the first step, with the complementary decomposition, the prototype transfer
function is obtained by two all-pass filters, while in the second step, by their addition or subtraction,
transfer functions of lowpass and highpass filters are obtained. The advantage of such
a system is that the same hardware can be used for realization of both low frequency and high
frequency transfer functions.
Monte Carlo simulation of the realization of a double complementary analog filter pair
based on a parallel connection of two analogue all-pass filters showed that all-pass realization
is characterized by a small sensitivity of the attenuation characteristics to the component
tolerances in the filter pass-band, while the sensitivity in the stop-band is substantially higher
compared to the case of a standard cascade realization of the low-pass filter and the high-pass
filter.
By a suitable selection of the analysis filter bank and the synthesis filter bank, a condition
for suppressing the effects arising from the overlapping of the spectrum in banks for analysis
and synthesis can be fulfilled. The all-pass complementarity of an analogue filter bank points to
the fact that amplitude distortion, which is introduced by the analog bank of the analysis filters,
can be completely suppressed, so that the non-linearity of the group delay characteristics is the
predominant distortion.
In order to achieve a near perfect reconstruction of the signal, a new realization of the
group delay corrector was proposed, which makes it possible for the group delay to be constant
in a flat sense, i.e. with a number of flatness at the origin. An analysis of the sensitivity has
shown that the sensitivity of the correction of the group waveform in the filter pass-band that is
proportional to the square of the Q -factor of the pole. In other words, the group delay corrector
is very sensitive to the component tolerances
Electrical Characterization and Impedance Response of Lanthanum Doped Barium Titanate Ceramics
The dielectric permittivity and dissipation factor of La-doped and undoped BaTiO3 were investigated as a function of frequency and temperature. The impedance response was used to study the electrical properties of La-doped BaTiO3 over the temperature range from room temperature (RT) to 350 degrees C. La-doped and undoped BaTiO3, obtained by a modified Pechini method, were sintered in air at 1300 degrees C for 2 and 16 hours. The impedance spectra were analyzed in terms of equivalent circuits involving resistors, capacitors and constant phase elements (CPE). The most suitable electrical circuit for the interpretation of experimental results is found to be the equivalent circuit consisting of resistors and CPE elements which replace the capacitor elements. The contribution of grain boundary resistance to the total resistance of a system is remarkable at low temperature. Dielectric permittivity of doped BaTiO3 was in the range of 8000 to 12000 at 1 kHz and the dissipation factor was less than 1%
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