635 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
Optimal gait and form for animal locomotion
We present a fully automatic method for generating gaits and morphologies for legged animal locomotion. Given a specific animal’s shape we can determine an efficient gait with which it can move. Similarly, we can also adapt the animal’s morphology to be optimal for a specific locomotion task. We show that determining such gaits is possible without the need to specify a good initial motion, and without manually restricting the allowed gaits of each animal. Our approach is based on a hybrid optimization method which combines an efficient derivative-aware spacetime constraints optimization with a derivative-free approach able to find non-local solutions in high-dimensional discontinuous spaces. We demonstrate the effectiveness of this approach by synthesizing dynamic locomotions of bipeds, a quadruped, and an imaginary five-legged creature
Profiti gospodarenja srnećom divljači u lovištima središnje Srbije
SummaryThe aim of this paper is to analyze the total breeding stock market in 2021/2022, an estimate of the value of the stock of this type of game, the culling value and income per 100 ha of total hunting areas of all hunting grounds in Central Serbia. This research covered the roe deer breeding stock in the hunting grounds of central Serbia. Based on the analysis, the directions and possibilities for increasing the income in all hunting areas of Serbia has been considered. The assessment of the value of the roe deer breeding stock was determined according to the Rulebook (Official Gazette, No. 18/19), while the income from roe deer culling was calculated using the market price list given by the Hunting Association of Serbia for 2021/2022. It was determined that the value of the male roe deer stock is 6.506.000 €, while the value of the female and offspring stock is approximately 3.615.000€. Total income of culled game in 2017/2018 was 480.626 €, while the income per 100 ha of the total area of all hunting areas is 9€. The highest total income is generated by the Central Hunting ground and it amounts to 191.785 €. In order to achieve a higher profit from the management of roe deer at the hunting grounds of central Serbia, it is necessary to completely fulfill the planned culling with an increased inclusion of roebucks that have higher trophy mass.SažetakIstraživanjem je obuhvaćen fond srneće divljači, u lovištima središnje Srbije. Cilj rada je analiziranje ukupnog matičnog fonda u 2021/2022. godini, procijena vrijedosti fonda ove vrste divljači, vrijednost odstrela i prihoda na 100 hektara ukupne površine lovišta u svim lovnim područjima središnje Srbije. Na osnovi analize razmotrit će se smjernice i mogućnosti za uvećanje prihoda u svim lovnim područjima Srbije. Procjena vrijednosti matičnog fonda srneće divljači utvrđena je prema Pravilniku (Službeni glasnik, br. 18/19), dok je prihod od odstrela srna izračunat je po tržišnom cjeniku koji propisuje Lovački savez Srbije za lovnu 2021/2022. godinu. Utvrđeno je da vrijednost fonda mužjaka koji iznosi 6.506.000 eura, te vrijednosti fonda ženki i podmladka oko 3.615.000 eura. Ukupan prihod odstrijeljene divljači u 2017/2018. iznosi 480.626 eura, dok je prihod na 100 hektara ukupne površine svih lovnih područja 9 eura. Najveći ukupan prihod ostvaruje Središnjo lovno područje i iznosi 191.785 eura. Prihodi po jedinici površine se razlikuju između različitih lovnih područja Srbije i dosta ovisi od intenziteta gospodarenje populacijama srneće divljači. Kako bi se ostvario veći profit od gospodarenja srnom običnom u lovištima središnje Srbije, potrebno je u potpunosti ostvariti planirani odstrel s povećanim učešćem srndaća veće trofejne mase
Estimation of 99mTc-ciprofloxacin accumulation indexes in bone and joint bacterial infections
Background/Aim. 99mTc-ciprofloxacin is a radiopharmaceutical preparation sintetized to improve diagnostic accuracy of bacterial infections in human tissues. It is mostly applied in diagnosis of bone and joint infections. Many papers have confirmed its sensitivity to infection, but newer papers argued its specificity. The aim of this study was to compare the results of visual analysis of scintigrams to semiquantitative calculations of accumulation indexes with the assumption that calculation of indexes would improve the specificity for bone and joint infections. Methods. We examined 40 patients, 25 with confirmed bone and joint bacterial infections and 15 patients with bone and joint diseases without bacterial infection. Scintigraphy was performed 5 minutes, 1, 4 and 24 hours after intravenous (iv) injection of 99mTc-ciprofloxacin. Scintigrams were analyzed visually and by calculation and comparation of accumulation indexes values. Results. Visual sensitivity was 94%, but specificity only 47%. Index calculation achieved much higher specificity (100% after 1, 4 and 24 hours for cut off value of 1.50). All basic index values (5 min) in the patients with infections increased in 24 hours. In 8 patients without infection occurred a slight increase and in 7 patients decrease of basic index values. Conclusion. Calculation of accumulation index values is needed in the use of 99mTc-ciprofloxacin scintigraphy as it is the only way to improve specificity for bacterial bone infections. Visual interpretation of results is sensitive, but not specific due to accumulation of the drug in a high percent of non infected bone and joint lesions
Application of diversity techniques for solving the problems of the effects impurities in optical fibers on the performance of optical systems
We analyzed the methods for reducing the impact of noise and interference, the performance
of digital optical IM-DD system.
Performances of digital optical telecommunication systems, as well as their improvement,
were analyzed using standard criteria for evaluation: outage probability, average probability,
channel capacity, and average fading duration. These performance measures are determined
on the basis of statistical characteristics of the first and second rows of signal reception and
are part of the technical documentation accompanying each of the realized digital optical
communication system. Therefore, the closed form of expressions, derived in this
dissertation, which can be used to calculate the statistical characteristics of signal reception,
represent a significant contribution, in terms of design of digital optical transmission systems.
Our analysis is placed on theoretical consideration on so far untreated cases, and therefore the
theoretical basis of physical phenomena that affect the transmission through the digital
optical systems, well known from the literature, are not further elaborated. We included a
procedure for determining the expression for the multidimensional joint probability density
distribution with correlated and uncorrelated random variables.
The derived expressions have a wide range of applicability and are an excellent basis for
further performance analysis of optical digital transmission systems, in terms of correlated
channels, as well as the characteristics of the connection by using multiple-input receiver.
Their practical use is demonstrated especially in the section that deals λSK optical systems,
as well as the part of that processes - the relay optical systems. Improving the transmission
reliability and reducing the impact of noise and interference on the performance of digital
optical telecommunication systems, with a reduction in power transmission and increasing
the distance between the transmitter and receiver, is analyzed through the applying of
techniques using spatial diversity reception.
The dissertation discussed the various techniques of spatial combining receiving signals from
the receiving branches of optical systems, in terms of reducing impact noise and interference.
Ratios were formed and interference signals at the entrance combiner branches and under the
terms of the previous chapter are determined by the joint probability density of these
relationships for all incoming branches and the corresponding joint cumulative probability.
Using this statistical feature of the incoming signal and interference are determined and
statistical characteristics of signal-to-interference at the output of given combiner, which
represents the next significant contribution to the dissertation.
The contribution of these derived expressions can be seen from the aspect of using the results
obtained for the case of the proposed statistical modeling of the channel model when
considering the reduction of the impact of various types of noise and interference, and
examination performance enhancements of digital optical telecommunication systems using
diversity reception techniques. Specifically, by assigning appropriate values of parameters in
the corresponding expressions, which describe the statistical characteristics of the first order
of receipt, an analysis of the value of standard measures of performance of optical
telecommunication systems, as well as improve their use of spatial diversity techniques, for
cases when the communication channel is exposed to various types of interference and
noises. Using the derived expressions can be shown to improve all the standard measure of
performance of optical telecommunication systems.
Also, when transferred unchanged forces the useful signal and interference, and at the same
range of connections, get better system performance (lower values of the probability of
cancellation, less the value of average bet error probability, lower average fading duration...).
Based on these facts can be concluded that the required the outage probability values (ABEP)
for the reception, when we apply the described techniques of receipt, in the same range of
connections and the same noise power, can achieve the necessary reduction of the useful
signal power in transmission, that is, at the same useful signal power, the same level of
interference in the channel, the required the outage probability (ASEP) at the reception, when
we apply the described techniques of receipt, can be achieved at larger distances from the
transmitting terminal
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