OUTAGE ANALYSIS OF LOW-LATENCY COOPERATIVE WIRELESS NETWORKS WITH THRESHOLD-BASED PROTOCOL OVER COMPOSITE FADING

This paper studies a low-latency decode-and-forward cooperative wireless network subject to composite fading. Assuming temporally correlated channel between cooperating nodes and maximal ratio combining at the destination, outage probability (OP) performance is investigated and novel OP expressions are derived when nodes apply a threshold-based protocol for internode communication. The effects of network dimension, multipath fading and shadowing severity parameters, correlation coefficients and average uplink and internode signal-to-noise ratios on OP are discussed

Antibacterial examination of carvacrol, eugenol, cinammaldehyde and thymol against Staphylococcus aureus isolated in cases of cow mastitis.

taphylococcus aureus predstavlja jednog od najznaĉajnijih uzroĉnika mastitisa krava, koji dovodi do velikih zdravstvenih problema i ekonomskih gubitaka u proizvodnji mleka. Imajući u vidu sve prisutniju rezistenciju prema antibioticima sojeva S. aureus izolovanih kod mastitisa, odnosno zabranjenu ili ograniĉenu upotrebu antibiotika u organskoj proizvodnji, etarska ulja imaju sve veći znaĉaj u terapiji obolelih grla. Cilj ovog istraţivanja je bio da se ispita: antibakterijsko delovanje odabranih komponenti etarskih ulja: karvakrola, eugenola, cinamaldehida i timola na sojeve S. aureus izolovanih u sluĉajevima supkliniĉkih mastitisa krava, njihovo sinergistiĉko delovanje u teĉnoj kulturi, kao i delovanje na biofilm S. aureus. Za ispitivanja na kliniĉkim izolatima, korišćeni su uzorci prikupljeni u toku redovne kontrole sa podruĉija koje obuhvata 8500 mleĉnih grla, holštajn-frizijske rase. Osim kliniĉkih izolata u radu su korišćeni i referentni sojevi S. aureus ATCC (American Type Culture Collection) 25923 i meticilin rezistentni S. aureus ATCC 43300. Kao kontrolni soj za produkciju biofilma korišćen je izolat S. aureus sa Instituta za mikrobiologiju, Medicinskog fakulteta, Univerziteta u Beogradu. Da bi se postigli postavljeni ciljevi korišćene su i klasiĉne mikrobiološke metode izolacije identifikacije S. aureus, kao i PCR metoda molekularne detekcije: nuc gena za proizvodnju termostabilne nukleaze koji se pojavljuje u razliĉitim alelnim formama kod S. aureus, S. intermedius i S. hyicus, na ĉemu se zasniva identifikacija vrste, zatim coa gena za produkciju koagulaze i ica A i D alelne forme gena koji kodira produkciju biofilma. Disk difuzionom metodom ispitivana je osetljivost izolata na antimikrobne supstance, zastupljene u terapiji mastitisa u Srbiji. Metodom odreĊivanja minimalnih inhibitornih i baktericidnih koncentracija antimikrobnih supstanci odreĊema je osetljivost izlata S. aureus prema aktivnim komponentama etarskih ulja karvakrola, eugenola, cinamaldehida i timola u koncentracijama od 2560μg/ml do 1,25μg/ml i kontrolnim antibioticima linkomicinu, neomicinu i kloksacilinu. OdreĊivanje meĊusobnog odnosa na antimikrobno dejstvo aktivnih komponenti u vršeno je modifikovanom metodom šahovske table, dok je odreĊivanje duţine antibakterijskog delovanja izvršeno time – kill metodom u mleku u trajanju od 14 dana uz tri dodatne inokulacije bakterija 2., 4. i 6. dana ispitivanja...Staphylococcus aureus is one of the most important causes of cow mastitis that leads to major health problems and economic losses in milk production. Essential oils and their active components are gaining importance in the treatment of mastitis patients due to growing antimicrobial resistance of S. aureus strains, as well as due to prohibited or limited use of antibiotics in organic production. The aim of this study was to examine: antibacterial activity of selected essential oil components: carvacrol, eugenol, thymol and cinnamaldehyde on S. aureus isolated in cases of subclinical mastitis in cows, their synergistic effects, and the effect on the S. aureus biofilm. To achieve these goals, clinical isolates were used, collected during regular checkups in the areas covered by 8500 dairy cattle of the Holstein-Friesian breed. Beside clinical isolates reference strains of S. aureus ATCC (American Type Culture Collection) 25923 and meticillin-resistant S. aureus ATCC 43300 have been used. Control used for the production of S. aureus biofilm was the strain from the Institute of Microbiology, Faculty of Medicine, University of Belgrade. In order to reach the set objectives, classical microbiological methods of isolation and identification of S. aureus were used as well as the PCR methods of molecular genetic detection: nuc gene for the production of thermostable nuclease that appears in different allelic forms in S. aureus, S. intermedius, and S. hyicus, which is used for identification species, then coa genes for the production of coagulase, and ica A and D allelic forms of the gene coding the production of a biofilm. Disk diffusion method was used in testing of the isolates’ sensitivity to antimicrobial substances, present in the treatment of mastitis in Serbia. Determining the minimum inhibitory and bactericidal concentrations of antimicrobial substances was used to describe S. aureus isolates to the active components of essential oils: carvacrol, eugenol, cinnamaldehyde and thymol in a concentration of 2560μg / ml to 1,25μg / ml and control antibiotics as well lincomycin, neomycin and cloxacillin. Determination of influence between the antimicrobial activities of active components was performed by chessboard modified method, while the length of antibacterial activity was tested by time - kill method in milk for 14 days with three additional reinoculation of bacteria on the 2nd, 4th and 6th days of testing..

Evaluation of toothbrush contamination

Background/Aim: Toothbrushes are one of the main means of cleaning teeth and maintaining oral hygiene, but toothbrushes are also potential reservoir of microorganisms, including pathogens. The aim of this paper was to evaluate the oral health, oral hygiene awareness and assess the degree of contamination of toothbrushes among students attending Secondary Medical School. Material and Methods: Sixty students (32 boys, 28 girls; mean age ≅ 15,7±2,1) attending highschool were randomly selected for this study. Each student included in the study filled out a questionnaire regarding his/her life habits and oral hygiene. Clinical examinations were initiated in order to determine the DMFT, as well as the CIP, CIT, CIA and CPITN indexes, based of which the assessment of oral health status was performed. One stack of fiber was collected from each toothbrush used by the participantes in the study, and than prepared for further microbiological sampling. Results: Only 11% of the students had the awareness of potential sources of toothbrushes contamination. The average value of DMFT was 3,2 (%D = 22,5; %M = 4,96; %F = 72,5). A statistically significant difference in comparison of the CPITN index and subjects' response to the professional plague removal in the last 12 months was identified (χ2 = 13,55; p= 0,033). Staphylococcus aureus, Streptococcus mutans, Micrococcus species and Streptococcus salivarius were most commonly present microorganisms. In most cases, G-positive bacilli or cocci were isolated, while the presence of Candidae albicans was identified in four samples. Conclusions: Raising the awareness of dental hygiene through the oral health education may improve better plaque control and subsequently the oral health. Hands-on training how to maintain the oral hygiene are not expensive and more over they are easy to be organized can be useful in oral heath promotion

Determining Free-Flow Speed on Different Classes of Rural Two-Lane Highways

Current analytical free-flow speed models consider all rural two-lane highways as the same road type despite their different functional significance in the network. The aim of this paper is to develop a prediction model for free-flow speed as a function of speed limit and road geometric characteristics for different classes of rural two-lane highways. The research was conducted on 50 representative sections of the two rural classes of two-lane highways equipped with automatic traffic counters in Serbia. In order to develop the appropriate models, it was necessary to determine the threshold values of vehicle time headway in the free-flow for both classes of rural two-lane highways, based on the total number of 191,720 vehicles. The obtained results show that there are differences in the threshold values of free-flow time headway for different road classes. Namely, it was determined that the values of free-flow time headway for Class I amounted to 6.3 s, and for Class II to 8.4 s. The free-flow speed prediction model for different road classes showed that speed limit had the highest impact on free-flow speed for Class I and II highways, followed by horizontal curve radius and shoulder width

Performance analysis for industrial wireless networks

Industrial wireless networks operate in harsher and noisier environments compared to traditional wireless networks, while demanding high reliability and low latency. These requirements, combined with the constant need for better coverage, higher data rates and overall seamless user experience call for a paradigm shift in communication in regards to the previous generations of technologies used. Cooperative diversity is one such approach. The main focus of this thesis is on the performance analysis of cooperative wireless networks set in industrial environments – where the network, apart from additive white Gaussian noise, is subject to multipath fading and shadowing, and/or temporary random blockage effects. In these scenarios, in order to achieve specific performance metrics such as error rates or outage probabilities, existing cooperative strategies are aided by protocols in the channel between the cooperating nodes. Moreover, pair-wise analysis investigates the correlation of multiple data flows. Building upon existing repetition protocols, outage performance of a network subject to fading and shadowing is observed, and the effects of fading and shadowing severity, network dimension, average signal-to-noise ratio values and packet length are discussed. Special cases are also observed, in which the composite fading channel is reduced to several familiar propagation environments, unifying the analysis. Afterwards, the analysis of more complex protocols is presented, taking into account random blockage in the channels between cooperating nodes. A novel, threshold-based internode protocol is introduced, which improves performance by listening to the transmissions and choosing whether to send a packet immediately or after a waiting period. As these two periods are close, the effect of temporal correlation is also investigated. Apart from the exact outage probability expressions, simpler asymptotic expressions, with and without blockage, are derived as well, giving a better insight on the network behaviour at high average signal-to-noise ratio regimes. Both outage probability and packet error rate can be also improved by adding automatic repeat request schemes in the channel between cooperating nodes, which again utilize the internode channels by re-sending data until it can be successfully decoded. Error-free communication can be achieved, but at a delay cost. Nevertheless, a trade-off between performance gains and delays remains, and can therefore be used for designing wireless networks with different requirements – error-free or low-latency. Finally, joint outage performance is investigated. Using a generic approach, which can be applied to any sort of data where multiple sources are communicating over wireless networks, pair-wise behaviour is investigated. As a result, any multi-route diversity type of scheme will have this sort of behaviour, since particular point-to-point relay links are being shared by source nodes. This in turn means that the performance of those flows will be correlated. For higher layers, there is a difference in the behaviour, meaning that when errors are correlated, data flows start behaving correlated as well. As a result, negative acknowledgements may start to correlate as well. All of this contributes to the network behaving in a correlated way, i.e., when something happens, it tends to happen to more than one data flow

Primena svetlosti u antimikrobnoj terapiji

Priča o prevenciji i kontroli zaraznih bolesti ostaje otvorena jer se niz patogenih bakterija iznova pojavljuje kao izazivač infekcija. Da bi se taj problem prevazišao, antibiotici su bili dominantni tokom prethodne ere. Rezistencija kao fenomen kojim se patogenimikroorganizmi opiru dejstvu lekove je postavo izuzetno raširen u svetu. Više naučnih pravaca se razvija u svrhu prevazilaženja ovog problema, pa je tako fotodinamička inaktivacija definisana u platformu za otkrivanje i razvoj antimikrobnih sredstava. Koncept fotodinamičke inaktivacije je prilično jednostavan i zahteva izlaganje mikroba energijom svetla koja uzrokuje pobuđivanje molekula, što rezultira proizvodnjom singlet kiseonika ili drugim reaktivnim kiseoničkim vrstama koje reaguju sa intracelularnim komponentama, a posledično dovode do ćelijske inaktivacije. To je oblast sve većeg interesovanja, kao i istraživanja u smerovima: (1) da se identifikuju fotohemijski i fotofizički mehanizmi uključeni u inaktivaciju, (2) da razviju moćni i klinički kompatibilni fotosenzibilizatori, (3) da se razume kako na fotoinaktivaciju utiču ključni mikrobni fenotip elementi (rezistencija na više lekova i efluks, virulencija i determinante patogeneze, biofilmovi), (4) da se istraže nove platforme za isporuku inspirisane trenutnim trendovima u farmakologiji i nanotehnologijama i (5) za identifikaciju fotoinaktivacije primene izvan kliničkog okruženja kao što je životna sredina tj. dezinfekciona sredstva.Srpsko društvo za osvetljenje - organizator savetovanj

Mastitisi kod koza

Mastitisi su zapaljenski procesi u mlečnoj žlezdi prouzrokovani mikroorganizmima i predstavljaju bolest sa posledično velikim ekonomskim štetama zbog smanjenja količine i kvaliteta mleka, troškova lečenja i odbacivanja mleka tokom lečenja. Mastitisi i etiologija mastitisa kod koza su u osnovi slični kao kod krava. Mogu da se pojave u akutnom ili perakutnom obliku sa teškim opštim stanjem praćenim mortalitetom i supkliničkom obliku bez simptoma i uginuća, ali sa održavanjem infekcije u vimenu i kliconoštvom u stadu. Koagulaza negativne stafilokoke (KNS) imaju najveću prevalenciju i mogu izazvati perzistentne infekcije, praćene povećanjem broja somatskih ćelija u mleku i slabo izraženim oblikom sa rekurentnim kliničkim epizodama. Incidencija intaramamarnih infekcija kod koza izazvanih sa Staphylococcus aureus je niska (<5%), ali može da rezultira perzistentnim infekcijama, koje ne daju odgovor na terapiju. Infekcije izazvane streptokokama mogu da budu suppkliničke i kliničke i češće se pojavljaju kod goveda. Bakterija Streptococcus agalactiae, nije čest uzročnik mastitisa kod koza. Kao kod krava i kod koza, gram‑negativni mikroorganizmi izazivaju interminentne infekcije. Infekcija sa bakterijom Trueperella pyogenes može da izazove multiple nodularne apscese u vimenu koza. Kontagiznu agalakciju izazivaju Mycoplasma agalactiae, a poslednjih godina i M. mycoides capri. U manjem broju slučajeva se dijagnostikuju M. capricolum capricolum i M. putrefaciens. Ovo oboljenje, pored mastitisa, prate artritisi i respiratorni poremećaji. U dijagnostici mastitisa je vrlo bitna diferencijalna dijagnoza zbog toga što i pri infekciji kozijim artritis i encefalitis virusom (CAEV) mogu nastati indurativne lezije u vimenu. Dijagnostika, praćenje i lečenje bakterijskih mastitisa koza su slični kao kod krava. Praćenje broja somatskih ćelija u dijagnostičke svrhe je otežano zbog teškog razlikovanja inficiranih od neinficiranih životinja, posebno u kasnom stadijumu laktacije. Ovo se pripisuje većem broju epitelnih ćelija u mleku koza u odnosu na mleko krava. Smatra se da je 1 000 000 ćelija/ml mleka koza uobičajen broj ćelija pred kraj laktacije. Cilj ovog rada je da se ukaže na značaj mastitisa kod koza, njihovu pravilnu dijagnostiku i lečenje. Higijena držanja i muže, kao i poseban odnos prema lečenju su ključni za prevenciju mastitisa kod koza

Otkrivanje prisustva PBP2a (Penicillin-binding proteina 2a) i mecA gena kod meticilin rezistentnih Stafilokoka poreklom od životinja

For the purpose of detecting methicillin (oxacillin) resistance in staphylococcal strains, in a number of microbiological laboratories only disc diffusion method with cefoxitin and/or oxacillin discs is used. Besides this method, it is desirable to determine MIC values for cefoxitin and/or oxacillin. After examination by disc diffusion and dilution methods, latex agglutination is used for the detection of PBP2a and PCR is used for the detection of mecA gene. Use of PCR is not possible in a large number of diagnostic laboratories and as method of choice, latex agglutination test for rapid detection of PBP2a is recommended. In this investigation, as confirmatory methods, latex agglutination and PCR were used for strains that were resistant to oxacillin and/or cefoxitin by disc diffusion and broth microdilution methods. In total, 14 strains of coagulase-negative staphylococci originating from clinical specimens of cats, dogs and chicken were examined. Among isolated strains, it was established that the dominating species was Staphylococcus haemolyticus with 11 isolated strains. Other isolated species were Staphylococcus epidermidis, Staphylococcus capitis and Staphylococcus vitulinus, each with one isolated strain. For all 14 strains, oxacillin MIC values ranged from 0.5 μg/mL to >64 μg/mL and cefoxitin MIC values ranged from 1 μg/mL to >256 μg/mL. Positive agglutination reaction by latex agglutination test was recorded in 13 out of 14 strains. The PCR assay for mecA gene was positive in 12 investigated strains.Radi otkrivanja meticilin (oksacilin)-rezistentnih sojeva stafilokoka u većini mikrobioloških laboratorija koristi se najčešće samo disk difuziona metoda uz primenu antibiogram diskova oksacilina i cefoksitina. Pored navedene metode, poželjno je da se utvrde i vrednosti MIC oksacilina i/ili cefoksitina primenom dilucione metode u bujonu ili agaru. Nakon ispitivanja pomenutim metodama za definitivno utvrđivanje pripadnosti soja grupi meticilin rezistentnih stafilokoka, koriste se metoda lateks aglutinacije za utvrđivanje prisustva PBP2a i PCR metoda za detekciju mecA gena. Kako primena metode PCR nije moguća u većini laboratorija koje se bave rutinskom dijagnostikom, kao metoda izbora preporučuje se lateks aglutinacioni test za brzo otkrivanje PBP2a. U ovom ispitivanju primenjeni su lateks aglutinacioni test i PCR metod, kao potvrdne metode za ispitivanje sojeva stafilokoka koji su bili rezistentni na oksacilin i/ili cefoksitin na osnovu rezultata dobijenih disk difuzionom metodom i mikrodilucionom metodom u bujonu. Ukupno je ispitano 14 sojeva koagulaza - negativnih stafilokoka izolovanih iz kliničkih uzoraka poreklom od pasa, mačaka i kokoši. Među izolovanim sojevima, ustanovljeno je da dominira vrsta Staphylococcus haemolyticus sa 11 izolata, a po jedan soj je izolovan od vrsta Staphylococcus epidermidis, Staphylococcus capitis i Staphylococcus vitulinus . Vrednosti MIC oksacilina za 14 sojeva iznosile su od 0.5 mg/mL do >64 mg/mL, a vrednosti MIC cefoksitina iznosile su od 1 mg/mL do >256 mg/mL. Kod 13 od 14 sojeva utvrđena je pozitivna reakcija aglutinacije primenom lateks aglutinacionog testa. Kod 12 ispitivanih sojeva je utvrđeno prisustvo mecA gena PCR metodom

Distribution of locomotor lesions in dairy cows in Serbia

Lameness causes significant economic losses in dairy cows. Lesions of the foot are the cause of about 85% of all lameness in dairy cows. In addition, lameness can be localized in other places of the locomotor system such as joints, muscles, and skin. The aim of this study was to show the distribution of locomotor lesions in dairy cows. A total of 144 Simmental dairy cows (36 primiparous and 108 multiparous) from 10 small dairy farms located in the Macva district, Serbia were observed during regular hoof trimming. All cows were housed in a tiedholding system. The clinical examination focused on all possible alternations on the observed hooves and legs. Lesions of the horn, skin, joints, and leg injuries were noted. Of the 144 animals presenting for a hoof trim, 49 cows (34.0%) had no locomotor lesions noted. In this study, lesions were present in 95 (66,0%) of all examined cows. Locomotor lesions of the horn were detected in 82.4% (61/74 of cases), skin 2.7%, joints in 10.8%, and leg injuries in 4.05% of the cases in multiparous cows. Thus, lesions of the horn were detected in 61.9% (13/21 of cases), skin 4.7%, joint in 23.8% and leg injuries in 9.5% of the cases in primiparous cows. Our results show that lesions on the hooves are the most dominant site of the locomotor system.Book of abstract

ON THE SELECTION OF SUITABLE BLOCKCHAIN TECHNOLOGIES FOR SUPPLY CHAIN MANAGEMENT

In the ever-expanding field of software engineering, the challenge of trust between different users and stakeholders of a software solution is becoming more prevalent. Software end users aim to be fully certain that the solution and/or service is in accordance with their requirements, with no deviations in quality of the selected or ordered solution and/or service. All actors in such a system are incentivized to secure and protect their own data, which is ultimately stored, processed and transferred within such a software system. In this paper, we demonstrate the applicability of an innovative approach to data storing and processing, and information exchange by implementing blockchain technologies, presented in a supply chain management case study. After selecting the appropriate technology, we focus on the security aspects which blockchain technology provides for our use-case. Finally, we test the model with transparency and information integrity hypotheses, network security challenges, and inappropriate actor behavior