Applicability ofMathematicalModels in Defining the Behaviour Kinetics Distinction Among Microbial Strains

Mathematical models were applied to define the behaviour kinetics distinction among microbial strains. In the first series of experiments the growth kinetics of microbial colonies of several S. rimosus mutant strains cultivated on agar plates were compared. Then, the interest was focused on the chosen two strains, in order to express mathematically their differences with respect to their colony growth and antibiotic biosynthesis kinetics. Finally, the behaviour of selected three S. rimosus derivative strains at different culture conditions was subjected to the study, with an aim to define strain distinction parameters. Mathematical models based on the three-dimensional growth concept and describing the microorganism growth, substrate uptake and antibiotic biosynthesis kinetics were developed. The computer simulation was applied to verify the applicability of mathematical models. The excellent agreement of computer simulation with experimental data confirmed the hypothesis that the kinetics parameters can be successfully applied to define the behaviour distinction among different S. rimosus strains. In the case of selected three strains, S. rimosus R6–500, S. rimosus MV9R-1 and MV9R-2, it was established that they can be distinguished by their growth kinetics parameters, their substrate uptake kinetics parameters and their antibiotic biosynthesis kineticsparameters. The strain S. rimosus R6–500 showed to be superior with respect to all kinetics parameters, the strain S. rimosus MV9R-2 showed to be slightly inferior to it, whereas the strain S. rimosus MV9R-1 showed to be inferior with respect to the both mentioned strains, especially because it showed the pronounced active biomass reduction rate at all investigated culture conditions. Based on these and the corresponding previous results one can conclude that appropriate mathematical models can be recommended for defining parameters of microbial behaviour distinction among different microbial strains of S. rimosus species

The feeding value of the ration based on alfalfa haylage supplemented with high moisture corn in wether sheep

The objectives of the experiment were to examine the effects of high moisture corn (HMC) supplementation to alfalfa haylage (Medicago sativa L.) (AH) on feed intake, digestibility and nitrogen (N) balance in wether sheep. The study consisted of three feeding treatments incorporating AH only and AH supplemented with 5 or 10 g HMC d-1kg-1 body weight of Suffolk wethers. Inclusion of HMC in the AH based ration had negative linear effects on acid detergent fibre (ADF) intake (p<0.001) and digestibility (p<0.05) while a positive on the digestibility of dry matter (DM) (p<0.05), organic matter (OM) (p<0.01) and the digestibility of OM in DM (D-value) (p<0.01). A positive associative response of AH and HMC was observed for DM and OM ad libitum intake (g kg-1M0.75d-1) (quadratic, p<0.05 and p<0.01, respectively). Negative linear effects of AH and HMC were observed for nitrogen (N) intake (p<0.05). The inclusion of HMC into AH based ration did not influence N balance in wether sheep. It was concluded that a positive associative response of the two forages was recorded for a limited number of parameters, probably due to lower quality of HMC than required for improved utilization of the AH based ration

Problematika određivanja količine istaloženih azotnih jedinjenja na slatinska staništa nacionalne ekološke mreže

The exceedance in the critical load of nitrogen compounds is used by the European Environment Agency as an indicator of the biodiversity loss risk. This paper provides a general overview of continental saline habitats vulnerability (Slatine - in Serbian) located in central Banat within the National Ecological Network, caused by the deposition of nitrogen compounds. These compounds originate from manure of selected category of animals raised in settlements located in the vicinity of protected areas. The data on short-range deposition of nitrogen compounds within two zones were used for determining the areas of impact: the zone of probable impact (0-500 m) and the zone of potential impact (500-2000 m). According to the calculation results, the most vulnerable locations which, for the most part, belong to 'Rusanda' protected area, are the pastures directly surrounding village Kumane, pastures bordering Rusanda salty lake, including the lake itself.Prekoračenja kritičnih opterećenja azotnim jedinjenjima se koriste kao indikatori rizika gubitka biodiverziteta od strane Evropske agencije za životnu sredinu. U radu je dat okvirni prikaz ugroženosti slatinskih staništa nacionalne ekološke mreže koja je uzrokovana taloženjem azotnih jedinjenja iz stajnjaka izabranih životinja, poreklom iz naselja koja se nalaze u okruženju zaštićenih područja srednjeg dela Banata. Za određivanje oblasti uticaja korišćeni su podaci o kratkom dometu taloženja azotnih jedinjenja, unutar dva pojasa: pojas verovatnog uticaja (od granice zaštićenog područja do 500 m) i pojas mogućeg uticaja (500-2000 m). Na osnovu rezultata proračuna, kao posebno ugroženi lokaliteti izdvajaju se pašnjačke površine u neposrednom okruženju naselja Kumane koje najvećim delom pripadaju zaštićenom području 'Rusanda', pašnjaci uz Rusandu, kao i samo jezero

Maternal characteristics influencing the duration of breastfeeding in a breastfeeding support group

U radu su prikazani čimbenici koji utječu na trajanje dojenja majki članica grupa za potporu dojenju. Podaci su prikupljeni retrospektivno pomoću anketnog upitnika za samopopunjavanje. Korištene su definicije dojenja SZO. U istraživanju je sudjelovalo 210 članica grupa koje su tijekom prvih šest mjeseci dojenačke dobi došle na sastanak grupe najmanje četiri puta. S navršenih šest mjeseci doji ukupno 83,8% majki, a s navršena tri mjeseca isključivo doji 56% majki. Dojenje dulje od šest mjeseci pozitivno je povezano s prihodima kućanstva, vremenom donošenja odluke o dojenju, namjeravanim trajanjem dojenja i zadovoljstvom savjetima majke voditeljice grupe, a negativno s pušenjem prije trudnoće. U logističkoj regresijskoj analizi prediktori dojenja duljeg od šest mjeseci su namjeravano trajanje dojenja više od šest mjeseci (OR 4,27; 95% CI 1,63-11,17, P= 0,003) i nepušenje prije trudnoće (OR 3,07; 95%CI 1,29-7,30, P=0,011). Ovo je u nas prvo istraživanje karakteristika majki članica grupa za potporu dojenju i čimbenika koji utječu na trajanje dojenja majki u grupama. Buduća istraživanja trebala bi potvrditi zapažanje ove studije da aktivnosti grupa potiču majke u smislu povećanja trajanja dojenja.The study was conducted to analyse factors influencing the duration of breastfeeding among attendees of mother support groups. Data regarding breastfeeding duration was collected retrospectively by a self-reported questionnaire using WHO definitions for breastfeeding. 210 women who were regular attendees of mother support groups (with 4 or more attendances of the group meetings during the first 6 months postpartum) participated in the study. At 6 months post partum 83.8% mothers were breastfeeding and 56% did so exclusively at 3 months. In univariate analysis breastfeeding duration > 6 months was positively associated with family income, time of breastfeeding decision, intended duration of breastfeeding and perceived satisfaction with advice from the mother leader of the group. A negative association was found for maternal smoking. Using logistic regression analysis of factors associated with breastfeeding duration > 6 months, a positive association was found with intended duration of breastfeeding > 6 months (OR 4..27; 95% CI 1.63-11,17, P= 0.003) and maternal non-smoking before pregnancy (OR 3.07; 95%CI 1.29-7.30, P=0.011). This is the first reported study of maternal characteristics and factors influencing the duration of breastfeeding among mother support group attendees. Future research should determine if the decision on the duration of breastfeeding can be modified through attending support groups to enhance breastfeeding duration