344 research outputs found

    BER Performance of IM/DD FSO System with OOK using APD Receiver

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    In this paper, the performance of intensity-modulated with direct detection (IM/DD) free space optical (FSO) system using the on-off keying (OOK) and avalanche photodiode (APD) receiver is observed. The gamma-gamma model is used to describe the effect of atmospheric turbulence since it provides good agreement in the wide range of atmospheric conditions. In addition, the same FSO system with equal gain combining applied at the reception is analyzed. After theoretical derivation of the expression for the bit error rate (BER), the numerical integration with previously specified relative calculation error is performed. Numerical results are presented and confirmed by Monte Carlo simulations. The effects of the FSO link and receiver parameters on the BER performance are discussed. The results illustrate that the optimal APD gain in the minimum BER sense depends considerably on the link distance, atmospheric turbulence strength and receiver temperature. In addition, the value of this optimal gain is slightly different in the case of spatial diversity application compared with single channel reception

    Application of pMOS Dosimeters in Radiotherapy

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    The results of a study on pMOS dosimeters manufactured by Tyndall National Institute, Cork, Ireland and their sensitivity on radiation doses used in radiotherapy are presented. Firstly, we deal with analysis of defect precursors created by ionizing radiation, responsible for increase in fixed and switching traps, which are further responsible for threshold voltage shift as a dosimetric parameter. Secondly, influence of some parameters, such as gate bias during irradiation, gate oxide thickness and photons energies, on threshold voltage shift is presented. Fading of irradiated pMOS dosimeters and possible application of commercial MOSFETs in ionizing radiation dosimetry are also presented

    Induction motor IFOC based speed-controlled drive with asymptotic disturbance compensation

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    This paper presents the design of digitally controlled speed electrical drive, with the asymptotic compensation of external disturbances, implemented by using the IFOC (Indirect Field Oriented Control) torque controlled induction motor. The asymptotic disturbance compensation is achieved by using the DOB (Disturbance Observer) with the IMP (Internal Model Principle). When compared to the existing IMP-based DOB solutions, in this paper the robust stability and disturbance compensation are improved by implementing the minimal order DOB filter. Also, the IMP-based DOB design is improved by employing the asymptotic compensation of all elemental or more complex external disturbances. The dynamic model of the IFOC torque electrical drive is, also, included in the speed-controller and DOB section design. The simulation and experimental measurements presented in the paper illustrate the effectiveness and robustness of the proposed control scheme

    Radiographic cephalometry assessment of the linear and angular parameters on cranial base in children with skeletal class III

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    Background/Aim. In malocclusion of skeletal class III, mandible is located in front of maxilla in sagital plain, which is manifested by a lower value of the sagital inter-jaw angle than in skeletal class I, where the jaw sagital relation is normal. Apart from the deformities on mandible and/or maxilla, in skeletal class III deformities are also frequent on the cranial base. The aim of this research was to find the differences in the parameter values on the cranial base among the children with skeletal class III and the children with skeletal class I in the period of mixed dentition. Methods. After clinical examination and orthopan-tomography, profile radiography of the head was analyzed in 60 examinees, aged from 6−12 years. The examinees were divided into two groups: group 1 - the children with skeletal class III; group 2 - the children with skeletal class I. Both linear and angular parameters on the cranial base were measured, as well as the angles of maxillary and mandible prognatism and the angle of sagital inter-jaw relation. The level of difference in the parameter values between the groups was estimated and the degree of correlation of the main angle of the cranial base with the angles of sagital position of the jaws in each of the two groups was established. Results. A significant difference between the groups was found only in the average values of the angles of maxillary prognatism and sagital interjaw relation. In the group 1, the main angle of the cranial base was in a significant correlation with the angles of sagital positions of the jaws, while in the group 2, such significance was not found. Conclusion. There were no significant differences in the parameter values on the cranial base between the groups. There was a significant correlation of the main angle of the cranial base with the angles of sagital position of the jaws in the group 1 only.

    Uticaj inokulacije soje na mikrobiološku aktivnost zemljišta

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    Soil fertility is associated with the activity of soil microflora, which in its turn depends on the content of organic matter in soil, soil moisture, temperature and pH, mineral nutrition, effectiveness of nodular bacteria and the crop grown. An experiment was established in 2002 at Rimski Šančevi experiment field of Institute of Field and Vegetable Crops in which the soybean variety Afrodita was treated with microbial fertilizers NS-Nitragin and BactoFil B. The soybean variety and NS-Nitragin have been developed at the Institute, while BactoFil B comes from Hungary. The experimental design was random blocks with four replications. Each replication consisted of six 5-m rows spaced 0.5 m apart. Seed inoculation variants were: noninoculated control (Ø); inoculation with NS-Nitragin for soybean (N) immediately before planting; inoculation with NS-Nitragin and BaktoFil B incorporation in soil (N+Bac.B). We monitored the effect of inoculation on soil biological activity and effectiveness of the symbiotic association. The microbial fertilizers NS-Nitragin and BactoFil B positively affected the presence of the analyzed microbial groups in the soil. The microbial fertilizers improved the agrochemical and biological properties of the soil. The incorporation of the microorganisms also affected the effectiveness of the symbiotic association. Soybean yield was highest in the variant of inoculation with NS-Nitragin and BactoFil B incorporation in the soil. .Plodnost zemljišta vezana je sa aktivnošću njene mikroflore, koja zavisi od sadržaja organske materije u zemljištu, vlažnosti zemljišta, temperature, pH sredine, mineralne ishrane, efektivnosti kvržičnih bakterija kao i od biljke domaćina. Na Oglednim poljima Naučnog instituta za ratarstvo i povrtarstvo na Rimskim Šančevima u toku 2002 godine je postavljen ogled sa sojom (Afrodita) uz primenu mikrobiološkog đubriva NS-Nitragina i BactoFila B. Genotip soje poreklom je iz Instituta kao i mikrobiološki preparat NS-Nitragin za soju, a BactoFil B poreklom je iz Mađarske Ogled je postavljen po slučajnom blok sistemu u 4 ponavljanja, svako ponavljanje sadržalo je šest redova, dužine 5m, razmak između redova bio je 0,5m. Varijante inokulacije semena su bile: kontrolna (Ø) (neinokulisana); varijanta inokulisano seme neposredno pred setvu NS-Nitraginom za soju (N); inokulisano seme sa NS-Nitraginom i inkorporirani BaktoFil B u zemljište (N+Bac.B) Praćen je efekat inokulacije na biološku aktivnost zemljišta i efektivnost simbiotske zajednice. Mikrobiološka đubriva NS-Nitragin i BactoFil B utiču pozitivno na zastupljenost ispitivanih grupa mikroorganizama u zemljištu. Primenom mikrobioloških đubriva poboljšavaju se agrohemijske i biološke osobine zemljišta, unošenjem mikroorganizama koji obavljaju određene procese u zemljištu utiče se i na efektivnost simbiotske zajednice. Prinos zrna soje najveći je kod inokulacije semena sa NS-Nitraginom i inkorporiranim BactoFilom B u zemljište.

    Orthodontic Treatment of Dentofacial Deformities

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    Međučeljusni nesklad stvara velike probleme pacijentima i estetski i funkcionalno. Razlog dolaska pacijenata u Kliniku uglavnom je estetske naravi, jer se radi o mlađim osobama, a funkicionalne su smjetnje u drugome planu. Uzimanje hrane, govor i disanje u takvih su osoba znatno otežani. Prikazat ćemo jedan od slučajeva liječenje kombiniranoga dentofacijalnog deformiteta: PROGNATHISMUS ET LATEROGNATHISMUS MANDIBULARIS. Pacijentica, 34 godine. Iz anamnestičkih podataka nismo saznali da sličnih problema ima u obitelji. Motiv dolaska na Kliniku bio je estetske naravi, premda se je pacijentica žalila na bolove u oba čeljusna zgloba, otežano uzimanje hrane i na nešto teži izgovor pojedinih glasova. Plan liječenja donesen je na osnovi sljedećih potanko provedenih postupaka: • raščlamba lica rađena je na osnovi fotogarafija napravljenih iz profila i en face • raščlamba okluzije učinjena je na studijskim modelima • rentgenkefalometrijska raščlamba profilnog i AP kraniograma učinjena računalom i ručno samo je potvrdila već spomenutu dijagnozu Liječenje je provedeno isključivo intraoralnom i ekstraoralnim ortodontskim napravama te smo smatrali korisnim iznijeti naša iskustva ovakvim načinom liječenja. Izgled pacijentice nakon liječenja vidi se na slikama. Ponovne kefalometrijske raščlambe rađene su nakon završetka liječenja. Svi parametri su u granicama normale, kako se vidi iz tabele s prikazanim vrijednostima prije i poslije liječenja. Raščlambe mekih česti pacijentice također pokazuju znatne promjene, a odnosi nos, gornja usnica, donja usnica i brada veoma su dobri. Dentofacijalni deformiteti danas se vrlo uspješno rješavaju. Dobre studijske raščlambe, na osnovi kojih se određuje plan liječenja, jamstvo su uspješnoga liječenja. Vrlo malo je ostalo tajni u liječenju dentofacijalnih deformiteta, ali ona od terapeuta traži visoku profesionalnost i učinkovitost.Disharmony of the jaws presents a great aesthetic and functional problem for patients. The reason for reporting to a clinic is mainly of an aesthetic nature, since most commonly young people are involved, while functional disturbances remain secondary. Such persons have difficulty eating, speaking and breathing. We will present one case of combined dentofacial deformity: PROGNATHISMUS ET LATEROGNATHISMUS MANDIBULARIS. Female patient, 34 years old. From anamnestic data we did not find out whether there were similar problems in the family. The motive for reporting to the clinic was aesthetics, although the patient complained of pain in both temporomandibular joints, difficulty eating and somewhat more difficult pronunciation of certain vocals. A treatment plan was based on: • Analysis of the face, based on profile and en face photographs. • Analysis of occlusion, based on study models. • Roentgen-cephalometry of the profile and AP craniogram, performed on a computer as well as manually, confirmed the above mentioned diagnosis. The treatment was performed exclusively with intraoral and extraoral orthodontic appliances, and we therefore believe that it would be useful to present our experience with such a treatment method. The appearance of the patient after treatment can be seen on the photographs. Repeated cephalometric analyses were performed after completion of the treatment. All parameters were within normal limits, as can be seen from the table presenting pre- and post treatment values. Analysis of the soft tissues also shows significant changes, and relations between the nose, upper lip, lower lip and chin are very good. Today dentofacial deformities are successfully solved. Good study analyses, which serve as the base for planning treatment, guarantee successful treatment. There are very few secrets in ortognatic treatment, but it still requires high professionalism and effectivness

    With frequency simulation to design the monitoring of frame structures

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    Based on experience from the testing of the mining stacker in the copper mine in Bor, a practical procedure of frequency simulation of the enforced vibration of the structure was demonstrated. Modelling of the excitation was performed by the harmonic function of the eccentric mass of the belt conveyor drive. The paper shows how the drive frequency excitation affects the amplitude of vibration of the supporting structure. From this, the idea is presented - an algorithm for software that would allow for keeping the dynamic properties of the members of the structure within controlled range. An experiment for accelerating the structure and its FFT analysis in the frequency domain was performed. Dynamic modelling of the structure allows obtaining the objectivised concept of the measurement system for monitoring based on the given level of dynamic sensitivity of the parts of the structure

    With frequency simulation to design the monitoring of frame structures

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    Based on experience from the testing of the mining stacker in the copper mine in Bor, a practical procedure of frequency simulation of the enforced vibration of the structure was demonstrated. Modelling of the excitation was performed by the harmonic function of the eccentric mass of the belt conveyor drive. The paper shows how the drive frequency excitation affects the amplitude of vibration of the supporting structure. From this, the idea is presented - an algorithm for software that would allow for keeping the dynamic properties of the members of the structure within controlled range. An experiment for accelerating the structure and its FFT analysis in the frequency domain was performed. Dynamic modelling of the structure allows obtaining the objectivised concept of the measurement system for monitoring based on the given level of dynamic sensitivity of the parts of the structure

    The influence of ligands selective for distinct subtypes of the benzodiazepine binding site of GABAA receptors on rats' behavior in the Morris water maze

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    Klasični benzodiazepini deluju kao neselektivni pozitivni modulatori GABAA receptora koji sadrže α1, α2, α3 i α5 podjedinicu, i u uslovima kliničke primene dovode do razvoja anterogradne amnezije. Nasuprot tome, negativna modulacija na nivou ovih receptora dovodi se u vezu sa poboljšanjem odreñenih tipova memorije kod ljudi i životinja. Uprkos brojnim istraživanjima, precizna uloga različitih podjedinica GABAA receptora u memorijskim efektima benzodiazepina nije u potpunosti rasvetljena. Tome doprinosi činjenica da uticaj diazepama u memorijskim testovima kod knock in i knock out miševa nije ispitan u potpunosti, ali i nedostatak selektivnih liganada i odgovarajućih farmakoloških istraživanja. Ekvivalent pamćenju kod ljudi jeste specifičan oblik promene ponašanja eksperimentalnih životinja koji se kroz brojne parametre može kvalitativno i kvantitativno opisivati. Morisov vodeni lavirint (MVL) je jedan od najčešće korišćenih laboratorijskih testova u bihejvioralnim neuronaukama uopšte, a primenjuje se za proučavanje neurobiologije i neurofarmakologije prostornog učenja i memorije kod oglednih pacova. U okviru ove disertacije, primenom Morisovog vodenog lavirinta ispitan je uticaj supstanci koje deluju preko benzodiazepinskog mesta vezivanja GABAA receptora na učenje i pamćenje kod pacova Wistar soja. Cilj je bio da se uz pomoć supstanci koje imaju različite kombinacije afiniteta i efikasnosti na ovim veznim mestima utvrdi relativni doprinos svake od podjedinica GABAA receptora u memorijskim efektima koji se zapažaju u korišćenom testu, kao i stadijum memorijskog procesa (akvizicija, konsolidacija ili pozivanje memorije) koji je podložan uticaju pozitivnih neselektivnih modulatora. U istraživanju je pokazano da neselektivni pozitivni modulatori (diazepam i midazolam) na dozno-zavisan način dovode do oštećenja učenja i pamćenja u MVL-u. S obzirom na doze koje su pokazale aktivnost, ne može se isključiti i doprinos nekih nekognitivnih efekata u ukupnoj inkapacitaciji životinja koja se vidi u MVL-u. Efekti benzodiazepina u MVL-u uglavnom su ograničeni na fazu akvizicije memorije, s time što je pokazano da midazolam može da dovede i do oštećenja pozivanja...Classical benzodiazepines act as nonselective positive modulators at GABAA receptors containing α1, α2, α3 or α5 subunit, and in clinical practice cause anterograde amnesia. On the opposite, negative modulation at these receptor subtypes is linked to an improvement in certain types of memory, both in humans and animals. Despite numerous studies, precise role of different subtypes of GABAA receptors in memory effects of benzodiazepines are not fully elucidated. The possible reason could be the fact that memory effects of diazepam were not comprehensively tested in knock in and knock out mice, as well as the lack of subtype selective ligands and related pharmacological studies. An animal equivalent to human memory is a specific change in behavior that could be described and quantified using an array of motor parameters. Morris water maze (MWM) is one of the most frequently used laboratory tools in behavioral neuroscience. It is widely used for studying neurobiology and neuropharmacology of spatial learning and memory in laboratory rats. In the present study, we used the Morris water maze to examine the influence of ligands which act through the benzodiazepine binding site of GABAA receptors on learning and memory in Wistar rats. More specifically, we used ligands with different combinations of affinity and efficacy for this binding site, in order to investigate the relative contribution of distinct subtypes of GABAA receptors in memory effects in the Morris water maze. Furthermore, we investigated which of the three memory stages (acquisition, consolidation and retrieval) is sensitive to pharmacological effects of nonselective positive modulators. Our experiments showed that nonselective positive modulators (diazepam and midazolam) dose-dependently impaired learning and memory in MWM. With regard to the doses that were pharmacologically active, we could not have excluded the influence of some non-cognitive effects on general incapacitation that was seen in animals in MWM. Benzodiazepine effects in MWM are generally limited to memory acquisition, with the exception of midazolam impairing also memory retrieval..
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