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

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

A case of generalized argyria

Opisan je slučaj generalizirane argirije nepoznate etiologije kod osamdesetčetirigodišnje žene. Ona je prije deset do petnaest godina uzimala neke kapi za želudac, vjerojatno srebrni nitrat. Od tog vremena počela joj je tamniti koža na licu i rukama pa je danas tamno plavkasto-siva s izraženim kovinastim sjajem. Zrnca pigmenta nađena su i u korneji. Spektrografskom analizom komadića kože utvrđeno je prisustvo srebra. Drugih se kovina nije moglo naći. Srebro je u koži dokazano i histološkim pregledom kože. Zrnca su bila lokalizirana na tipičnim mjestima. Prikazani slučaj odgovara klasičnom opisu generalizirane argirije.A case of generalized argyria in a woman aged 84 is described. She took 10-15 years ago some stomach-drops (probably silver nitrate). From that time the skin in her face and on her hands began to darken. The skin of her head and hands is now dark bluish-grey with metallic shine. The skin on the forehead, scalp, ears, cheeks and neck is particularly dark. The remaining parts of the skin show a dirty blue-greyish discoloration but this change in the colour of the skin is much less pronounced. On the forearms and hands there are a few brighter scars up to 1/2 cm in size, originating from injuries at work which have not changed in colour. The mucous membrane of the mouth cavity is bluish-grey. The conjuctiva of the eyelids as well as bulbar conjuctiva are slate pale. An examination with the slit-lamp has revealed that granules of the pigment are located especially in the cornea and mostly close to Descemet\u27s membrane and in the lens. In the skin, granules of the pigment are located in the upper layers of the corium and in the membrana propria of the sweat glands. In dark field illumination brilliantly refractile granules of pigment are also visible in the same places. By spectrographic analysis of a specimen of the skin only silver was found

Thermally Induced Structural Transformations of Fe2O3 Nanoparticles Embedded in a Silica Matrix

XXV Konferencija Srpskog kristalografskog društva : Bajina Bašta, 2018

Fe3O4 nanoparticles as additives for gamma-ray shielding: Structural and surface characterization

Monodisperse samples of magnetite nanoparticles in the size range of 5-13nm, were prepared by solvothermal synthesis and coprecipitation method. Obtained nanoparticles were characterized by different measurement techniques: X-ray diffraction analysis, transmission electron microscopy, selected area electron diffraction measurement, and Fourier transform infra-red spectroscopy. Measurements confirmed that the utilized synthesis methods are able to produce size and shape-controlled nanoparticles of a high-quality, that is of the technological importance. The results of the performed study represent the first stage in preparation of the Fe3O4 nanoparticles as an additive to concrete, which will be used for the construction of the special military facilities where it is necessary to provide a protection against γ-ray radiation

Crystallization of Fe2O3 and Gd2Si2O7 in Fe2O3/Gd2O3/SiO2 composite system

XXIV Konferencija Srpskog kristalografskog društva : Vršac, 2017

Performanse i senzorni kvalitet mesa brojlera hranjenih različitim nivoima ekstrudirane sačme uljane repice

In this paper the effect of extruded rapeseed meal on the performance and sensory quality of the breast meat of broilers was investigated. The experiments were performed with hybrid line ROSS 308. The control group was fed soybean meal, and two levels of extruded rapeseed meal were added in experimental groups, 4% and 8% during a period of 42 days. Final body masses of chicken in the experimental groups were lower for 1.79% and 3.05% than the control group. Conversion of feed was satisfactory in all groups, and the best in the control group. Including extruded rapeseed meal in the meal did not show negative effect on the sensory quality, the smell and the colour, of fresh breast meat. Sensory quality (smell, taste and sensitivity) of heat-treated breast meat of the chickens in the control and experimental groups was marked as 'very good', or optimal.U radu je ispitivan efekat ekstrudirane sačme uljane repice na proizvodne performanse i senzorni kvalitet mišića grudi brojlera. Ispitivanja su obavljena na pilićima hibridne linije ROSS 308. Kontrolna grupa je bila na bazi sojine sačme, a u oglednim grupama su korišćena dva nivoa ekstrudirane sačme uljane repice, 4% i 8% u periodu od 42 dana. Završne telesne mase pilića u eksperimentalnim grupama su bile nešto niže i zaostajale za kontrolnom grupom 1,79 % i 3,05%. Konverzija hrane je bila zadovoljavajuća u svim grupama, a najbolja u kontrolnoj grupi pilića. Uključivanje ekstrudirane sačme uljane repice u obrok nije ispoljilo negativan uticaj na senzorni kvalitet (miris, ukus i nežnost) toplotno obrađenih mišića grudi pilića kontrolne i eksperimentalnih grupa je ocenjen kao 'veoma dobar', odnosno optimalan

Structural adaptation of Salsola soda L. (Chenopodiaceae) from inland and maritime saline area

The microscopic analysis of leaf and stem in two populations of Salsola soda was carried out in order to examine mechanism of anatomical adaptations to environmental condition on saline habitats and to determine if there exists a morpho-anatomical differentiation between populations from maritime and inland saline area. Analysis included 26 quantitative characters of leaf and stem. The results showed that both populations exhibited halomorphic and xeromorphic adaptations, which refered to ecological plasticity and adaptations of plants to their habitats. Our research also showed that S. soda had quite a stable morphoanatomical structure, since only quantitative changes were recorded. [Projekat Ministarstva nauke Republike Srbije, br. 173002

Crystal Structure of Citrobacter freundii Asp214Ala Tyrosine Phenollyase Reveals that Asp214 is Critical for Maintaining a Strain in the Internal Aldimine

Tyrosine phenol-lyase (TPL) is a pyridoxal-5′-phosphate (PLP) dependent enzyme which catalyzes β-elimination of L-tyrosine. In the holoenzyme the protonated pyridinium N1 atom of the PLP cofactor is hydrogen-bonded to the side chain of Asp214. Here we report the X-ray structure of C. freundii D214A TPL determined at 1.9 Å resolution. Comparison with the structure of the wild-type TPL shows that the D214A replacement induced significant conformational reorganization in the active site leading to its partial closure. Significantly, in D214A TPL the strain in the internal aldimine is completely released and the pyridine N1 atom of PLP is deprotonated. These observations explain the considerably reduced activity of the D214A TPL towards its substrates [T. V. Demidkina et al., Biochim. Biophys. Acta, Proteins Proteomics 1764 (2006) 1268–1276]. The reported structure reveals that Asp214 is critical for maintaining the strain in the internal aldimine. We argue that this strain is used by the enzyme to accelerate the transaldimination reaction, the first step in the enzymatic catalysis.(doi: 10.5562/cca1915

Različiti izvori i nivoi ulja u ishrani brojlera

The aim of this study was to investigate the effects of soybean, flax and rapeseed oil on productive performance and carcass quality of broilers chickens. At the beginning of the experiment six groups of 40 one day-old chicks, hybrid line Cobb 500 was formed, with five replications. For nutrition two feed mixtures were used. During the first two weeks, in preparation period, chickens were fed with starter mixture, and then with grower mixture until the end of the experiment. Control group was fed with mixture of standard composition and quality based on corn and soybean meal with the addition of 4% and 8% soybean oil, while the experimental group included 4% and 8% flaxseed oil and 4% and 8% rapeseed oil. The experiment lasted 35 days. During the experimental period, chickens were fed and watered ad libitum and microclimatic conditions were constantly monitored. Control of body weight and feed consumption was carried out every seven days. At the end of the experiment 10 chickens from each group were sacrificed for the purpose of testing the carcass quality. Upon completion of the experiment, control group achieved weight of 2122g and 2053g, and the experimental group with flax oil 2164g and 2094g, and the group with rapeseed oil weighs of 2121g and 2081g. Chickens on treatment with 4% flax oil in the diet achieved significantly higher body mass (P (lt) 0.05) at the end of the experiment compared with the groups who were on treatment with 8% rapeseed and soybean oil. Soybean oil at a rate of 4% showed significantly (P (lt) 0.05) increased final body weight compared to body mass of chicks in a group with the addition of 8% soybean oil. Feed conversion ratio was lowest in the group with the addition of 4% flax oil and rapeseed oil, and the highest in the group with the addition of 8% flax oil. The differences found in the carcass quality between the control and experimental groups were not statistically significant (P>0.05). The largest amount of abdominal fat (18.9 g) was in the group with the addition of 4% rapeseed oil and lowest in the group with the addition of 8% soybean oil (12.6 g). Based on these results it can be concluded that the addition of 4% oil showed better productive results, but had no effect on carcass quality of chickens.Cilj ovog rada je bio da se ispita efekat ulja soje, lana i uljane repice na proizvodne parametre i kvalitet trupa brojlera. Na početku ogleda formirano je šest grupa sa po 40 jednodnevnih pilića linijskog hibrida Cobb 500, u pet ponavljanja. Za ishranu su korišćene dve smeše. Tokom prve dve nedelje pripremnog perioda, za ishranu pilića je korišćena starter, a potom grover smeša do kraja eksperimenta. Kontrolna grupa je hranjena smešom standardnog sastava i kvaliteta na bazi sojine sačme i kukuruza sa dodatkom 4% i 8% ulja soje, dok je u eksperimentalnim grupama bilo uključeno 4% i 8% lanenog ulja, odnosno 4% i 8% ulja repice. Ogled je trajao 35 dana. U toku eksperimentalnog perioda piliću su hranjeni i napajani po volji, a mikroklimatski uslovi redovno kontrolisani. Kontrola telesne mase i utroška hrane je vršena svakih sedam dana. Na kraju eksperimenta žrtvovano je po 10 pilića iz svake grupe za potrebe ispitivanja kvaliteta trupa. Po završetku eksperimentalnog perioda, kontrolna grupa je ostvarila masu od 2122g i 2053g, a ogledne grupe sa uljem lana 2164g i 2094g, dok su grupe sa repičinim uljem ostvarile masu od 2121g i 2081g. Pilići na tretmanu sa 4% ulja lana u ishrani ostvarili su statistički značajno veću telesnu masu (P (lt) 0,05) na kraju eksperimenta u poređenju sa grupama koje su bile na tretmanu sa 8% ulja repice i soje. Ulje soje u količini od 4% je takođe statistički značajno (P (lt) 0,05) uticalo na povećanje završne telesne mase u poređenju sa telesnom masom pilića u grupi sa dodatkom 8% sojinog ulja. Konverzija hrane je bila najniža u grupi sa dodatkom 4% ulja lana i uljane repice, a najviša u grupi sa dodatkom 8% ulja lana. Utvrđene razlike u kvalitetu trupa između kontrolne i oglednih grupa nisu bile statistički značajne (P>0,05). Najveća količina abdominalne masti (18,9g) je u grupi sa dodatkom 4% ulja repice, a najmanja u grupi sa dodatkom 8% ulja soje (12,6g). Na osnovu dobijenih rezultata može se zaključiti da je dodatak 4% ulja ispoljio bolje prozvodne rezulate, ali nije uticao na kvalitet trupa pilića

Prediction of metabolisable energy of poultry feeds by estimating in vitro organic matter digestibility

The aim of this study was to develop equations to predict the in vivo apparent metabolisable energy (AME) of poultry feeds using an in vitro method for estimation of organic matter digestibility. In this study, a total of 57 samples of feedstuffs and 23 samples complete diets for poultry were used. Dry matter (DM), crude protein (CP), crude fibre (CF), crude fat (CFat) and crude ash (CA) of the diets were determined. A modified method for estimating the enzymatic digestibility of organic matter (EDOM) was used. For the determination of in vivo ME, the rooster digestibility assay was followed. Obtained laboratory results, that is in vitro and proximate analysis values were regressed against the in vivo ME values and equations for predicting the in vivo ME of feeds for poultry have been derived. Using CA, CF, CFat and in vitro EDOM as predictors, the following equation for predicting the in vivo ME in poultry feeds was derived: ME (MJ/kg DM) = 5.46 – 0.2166 x CA – 0.0946 x CF + 0.2219 x CFat + 0.1054 x EDOM (R2 = 0.844, RSD = 1.10). Using only EDOM as predictor generated the equation: ME (MJ/kg DM) = -0.41 + 0.1769 x EDOM (R2 = 0.689; RSD = 1.63). Results show that using only EDOM as a predictor was not as accurate as when the other variables were included.Key words: Metabolisable energy, prediction, poultry, feeds, organic matter digestibilit