NUMERICAL SIMULATION OF FLUID-STRUCTURE INTERACTION BETWEEN FISHING WOBBLER AND WATER

This paper deals with modeling, discretization, and numerical analysis of the two-way fluid-structure interaction between a fishing wobbler and a water stream. The structural domain is an assembly of several bodies that have multiple mutual structure-to-structure interactions. These interactions are mostly nonlinear contacts that significantly influence the time step used in simulations. As a result of these nonlinearities, the numerical solving of such a model requires significant computer resources and a long computational time. The paper also presents the creation and numerical simplifications of the model. However, the model remains very realistic. It is concluded that solving the structural domain in a model that retains the interaction between solid bodies is more computationally sensitive and more demanding than solving the fluid domain

Ispitivanje PGP svojstava i antifungalne aktivnosti izolata azotobaktera

Among 50 bacterial isolates obtained from maize rhizosphere, 13 isolates belonged to the genus Azotobacter. Isolates were biochemically characterized and estimated for pH and halo tolerance ability and antibiotic resistance. According to characterization, the six representative isolates were selected and further screened in vitro for plant growth promoting properties: production of indole-3-acetic acid (IAA), siderophores, hydrogen cyanide (HCN), exopolysaccharides, phosphate solubilization and antifungal activity (vs. Helminthosporium sp., Macrophomina sp., Fusarium sp.). Beside HCN production, PGP properties were detected for all isolates except Azt 7 . All isolates produced IAA in the medium without L-tryptophan and the amount of produced IAA increased with concentration of precursor in medium. The highest amount of IAA was produced by isolates Azt 4 (37.69 and 45.86 µg ml -1 ) and Azt 5 (29.44 and 50.38 µg ml -1 ) in the medium with addition of L-tryptophan (2.5 and 5 mM). The isolates showed the highest antifungal activity against Helminthosporium sp. and the smallest antagonistic effect on Macrophomina sp. Radial Growth Inhibition (RGI) obtained by the confrontation of isolates with tested phytopathogenic fungi, ranged from 10 to 48%.Među 50 izolata bakterija iz rizosfere kukuruza, 13 izolata pripadali su rodu Azotobacter. Izolati su biohemijski karakterisani i ispitana je tolerantnost prema reakciji sredine, koncentraciji soli i rezistentnost na antibiotike. Nakon karakterizacije, odabrano je šest reprezentativnih izolata za dalja ispitivanja PGP svojstava: produkcije indol-3-sirćetne kiseline (IAA), siderofora, cijanovodonične kiseline, egzopolisaharida, fosfosolubilizacije i antifungalne aktivnosti (prema Helminthosporium sp., Macrophomina sp., Fusarium sp.). Osim produkcije HCN, PGP svojstva utvrđena su za sve izolate osim Azt 7 . Najveću količinu IAA produkovali su izolati Azt 4 (37,69 i 45,86 µg ml -1 ) i Azt 5 (29,44 i 50,38 µg ml -1 ) u podlozi sa dodatkom L-tryptophan-a (2,5 i 5 mM). Izolati su ispoljili najveću antifungalnu aktivnost prema Helminthosporium sp., a najmanji antagonostički efekat prema Macrophomina sp. Procenat inhibicije rasta (RGI) dobijen suočavanjem izolata sa ispitivanim fitopatogenim gljivama kretao se od 10 do 48%

Varijabilnost komponenti prinosa ozime uljane repice (Brassica napus L.) i njihova korelacija sa prinosom semena

Designing breeding programs for rapeseed (Brassica napus L.) cultivars with improved seed and oil yields require information about the genetic variability of traits effecting seed and oil production. This investigation was undertaken in order to examine phenotypic and genetic variability, broad-sense heritability, genetic gain under selection and interrelationships of some agronomic and seed quality traits of investigated genotypes. Genotypes, years and their interaction showed significant variation for all studied characters. Phenotypic variability coefficients were higher than genetic ones. Broad-sense heritability estimates ranged from 12.66% (for ripening period) up to 52.12% (for days to first pods filling). Expected genetic gain was lowest for days to maturity (0.45%) and highest for height to the first lateral branch (12.94%). The analysis of genetic correlations revealed that seed yield per plant is highly and positively associated with pods per plant, oil content, plant height and ripening period, although significant negative correlations were found between seed yield per plant and leaves per plant, days to maturity, protein content, days to first pods filling, days to flowering, height of the first lateral branch and 1000 seed weight. Genetic path-coefficient analysis indicated that pods per plant and oil content were the most important components of seed yield per plant. Their direct effects on seed yield per plant were p=0.472 and p=0.082, respectively. Protein content had highly significant negative direct effect on seed yield (p=-0.365), followed by 1000 seed weight (p=-0.017) and height to the first lateral branch (p=-0.081). These observations will support the selection of genotypes with desired traits for further rapeseed seed and oil yield improvement.Za organizovanje dobrog oplemenjivačkog programa na uljanoj repicu (Brassica napus L.) neophodno je poznavanje genetičke varijabilnosti svojstava koja utiču na prinos semena i ulja. Istraživanja su sprovedena da bi se ispitala fenotipska i genotipska varijabilnost, heritabilnost u širem smislu, genetička dobit od selekcija i međuzavisnost agronomskih važnih osobina i svojstava kvaliteta semena kod ispitivanih genotipova. Genotipovi, godine i njihova interakcija signifikantno su varirale za sva ispitivana svojstva. Fenotipski koeficijent varijacije bio je veći od genotipskog. Heritabilnost u širem smislu kretala se od 12.66% (za vreme sazrevanja) do 52.12% (broj dana do formiranja prve mahune). Očekivana genetička dobit bila je najniža za broj dana do sazrevanja (0.45%) i najviša za visinu do prve bočne grane (12.94%). Analiza genetičkih korelacija ukazala je na visoku i pozitivnu vezu prinosa semena po biljci sa brojem ljuski po biljci, sadržajem ulja, visinom biljke i vremenom sazrevanja, a negativna korelacija je utvrđena između prinosa semena po biljci i broja listova po biljci, dana do zrenja, sadržaja proteina, broja dana do formiranja prve mahune, broja dana do cvetanja, visine prve bočne grane i težine 1000 semena Analiza koeficijenta putanje ukazala je da su broj ljuski po biljci i sadržaj ulja najvažnije komponente prinosa semena po biljci. Njihovi direktni efekti na prinos po biljci su bili p=0.472 i p=0.082. Sadržaj proteina imao je visokoznačajan negativan direktan efekat na prinos semena (p=-0.365), potom masa 1000 semena (p=-0.017) i visina do prve bočne grane (p=-0.081). Ova istraživanja predstavljaju osnov za dalje oplemenjivanje uljane repice poboljšanog prinosa semena i ulja

Comparative evaluation of insecticides in control of bothynoderes punctiventris germ. Under laboratory and field conditions

Beet weevil (Bothynoderes punctiventris Germ.) is the most damaging pest of sugar beet in south-eastern Europe, from seedling emergence and in the first phases of crop development. Efficacy of insecticides (active ingredients of chlorpyriphos + bifenthrin, chlorpyriphos + beta-cyfluthrin and chlorpyriphos + cypermethrin) for the control of beet weevil was tested during 2010 and 2011 under laboratory and field conditions. A wet filter paper method (contact action) was employed in laboratory tests. Simultaneously, field trials were conducted (Curug, Rimski Sancevi, Budisava, Kovilj) (contact and digestive action). The trial was designed according to EPPO method and insecticide efficacy was tested in accordance with the pest biology and phenophase of the crop. Insecticide efficacy was calculated using Abbot's formula, and damage of plants was assessed using 0-5 scale. Commercial insecticide Nurelle D (active ingredient of chlorpyriphos + cypermethrin) maintained high contact and digestive action on beet weevil, although it has been in use for 20 years. Commercial insecticide Pyrinex Super (active ingredient of chlorpyriphos + bifenthrin), although with reduced content of chlorpyriphos by 30% and of bifenthrin by 20%, achieved efficacy that was at the same level of significance with Nurelle-D, regardless of the experimental conditions (laboratory or field). Compared to Nurelle-D, the product MCW 784 (chlorpyriphos + beta-cyfluthrin) had significantly lower initial efficacy 3 h after application in laboratory trial, and also 24 h after application in field trial

Histopathological characteristics and expression of cdv-np antigen in the brain of serologically positive spontaneously infected red foxes (vulpes vulpes) in western Serbia

Canine distemper virus (CDV) is a worldwide distributed RNA virus that can cause severe disease in carnivore and non-carnivore species. Red foxes are highly susceptible and may act as a reservoir of the virus. As in other wild species, distemper in red foxes can manifest as acute, systemic and chronic nervous form. In the present study, we detected antibodies against CDV among red foxes in Western Serbia, and analyzed histopathologically and immunohistochemically for CDV nuclear protein antigen (CDV-NP) brain samples derived from seropositive animals. Seroprevalence of CDV antibodies was 36.8%. Histopathological changes included gliosis, neuronal degeneration, satellitosis, mononuclear inflammation, demyelination and presence of inclusion bodies. Immunostaining showed a diffuse presence of CDV-NP antigen, mainly in the cytoplasm of astrocytes and neurons. Results of this work contribute to the opinion that red foxes act as a potential reservoir of CDV and underline the importance of routine vaccination of dogs that could come in close contact with these animals. Potential active surveillance program would give a better insight in the degree of CDV infection in wildlife

Periodontal Disease Increases Risk for Chronic Obstructive Pulmonary Disease

The aim of this study was to explore whether a periodontal disease could be a risk indicator for a chronic obstructive pulmonary disease (COPD). The examined group comprised 93 patients with COPD (mean age 65.8 years). The control group comprised 43 systemically healthy individuals (mean age 62.1 years). Respiratory and periodontal conditions were examined in both groups. COPB subjects had significantly worse periodontal conditions than controls (p<0.05) with regard to each parameter of periodontal condition, except for gingival inflammation. COPD patients had higher Plaque Index than control patients (82.84±22.81 vs. 57.15±26.96; p<0.001), higher periodontal depth (3.02±0.92 vs. 2.57±0.79 mm; p=0.007), higher gingival recession (1.97±1.09 vs. 0.91±0.79 mm; p<0.001), and higher mean clinical attachment loss (CAL) (4.12±1.74 vs. 2.91±1.27 mm; p<0.001). Multiple logistic regression model, after controlling for other risk indicators, showed that periodontal disease, presented as CAL ³4 mm at ³60% sites, was associated with odds ratio of 3.2 (95% CI 1.0–9.8) for the COPB group. Data suggest that periodontal disease could be a risk indicator for COPD

Correlation and Path Analysis of Quantitative Traits in Winter Rapeseed (Brassica napus L.)

In the paper presented, 30 rapeseed cultivars were studied. Seed yield components and their interrelations were analyzed using simple coefficients of correlation. The direct and indirect effects of such components on seed yield per plant were estimated using path analysis. The following traits were considered: plant height, height of the first lateral branch, number of lateral branches, number of pods per plant, seed oil content, 1000 seed weight and seed yield per plant. The highest seed yield per plant was estimated for cultivars ‘Sremica’, ‘B-009’, ‘Jet Neuf’ and ‘Falcon’. There was a complete correlation between plant height and height of the first lateral branch and a very strong one between plant height and seed oil content, as well as between plant height and seed yield per plant. The strongest direct effect on seed yield per plant was estimated for plant height, followed by the effect of number of pods per plant. This kind of investigation helps rapeseed breeders to optimize their breeding programs