An application of Groebner bases to planarity of intersection of surfaces

In this paper we use Groebner bases theory in order to determine planarity of intersections of two algebraic surfaces in ${\bf R}^3$. We specially considered plane sections of certain type of conoid which has a cubic egg curve as one of the directrices. The paper investigates a possibility of conic plane sections of this type of conoid

On the Extension of the Erdos-Mordell Type Inequalities

We discuss the extension of inequality R_A >= c/a * r_b + b/a * r_c to the plane of triangle ABC. Based on the obtained extension, in regard to all three vertices of the triangle, we get the extension of Erdos-Mordell inequality, and some inequalities of Erdos-Mordell type

Creating an environment for free education and technology-enhanced learning

The purpose of this paper is to present a project aimed at making knowledge publically available through opene ducational resources (OER). The focus is on open online courses which will be created by educational institutions and best practice examples offered by leading companies, with the purpose to support life-long education and enhancement of academic education with practical knowledge. The goal is to create diverse high quality educational materials in electronic format, which will be publically available. The educational material will follow basic pedagogical-didactic principles, in order to best meet the needs of the potential learners. In accordance with that a review of didactic principles that can contribute to producing OER content of excellence is given. The choice of a convenient platform, as well as the application of appropriate information technologies enable content representation in a suitable, innovative and meaningful way

Teorijski model izračunavanja koncentracije amonijaka i kiseonika u vodi ribnjaka

Od kvaliteta vode u velikoj meri zavisi uspeh u proizvodnji riba. U gajenju pastrmki to znači da normalan rast, prirast, konverzija hrane, zdravstveni i reproduktivni status zavise osim od genetskih osobina i tehnologije proizvodnje i od ambijetalnih faktora, koji mogu direktno uticati na postizanje boljih ili slabijih rezultata u akvakulturnoj proizvodnji. U ovom radu su sa aspekta utvrđivanja koncentracija kiseonika i amonijaka u vodi istraživani teorijski modeli izračunavanja produkcije amonijaka i potrošnje kiseonika, kao jednih od najvažnijih parametara vode. Utvrđeno je da potrošnja kiseonika i ekskrecija amonijaka neposredno zavise od mase riba, temperature i protoka vode, vrednosti pH, količine hrane i sadržaja proteina u njoj. Prosečna razlika između teorijski očekivane i utvrđene koncentracije kiseonika iznosila je 5,72%. Teorijski dobivene prosečne vrednosti produkcije amonijaka, razlikovale su se od laboratorijski utvrđenih za 7,66% (metod Piper-a i sar.), odnosno za 11,16% (metod Colt-a)

Uticaj dodavanja zeolita na kvalitet mesa pastrmke

U radu je ispitivan uticaj zeolita tipa "Minazel" kao aditiva hrane za pastrmke primenjenog u koncentraciji od 1% i 2% na sledeće proizvodne parametre: osnovni hemijski sastav mesa, mikotoksikološku ispravnost, senzorne osobine, randman i koncentraciju pojedinih makro i mikroelemenata. Primenjene koncentracije zeolita, kao aditiva hrane nisu uticale na hemijski sastav pastrmskog mesa, koncentraciju minerala (Ca, Cu, Zn, Pb i Mn) i njegove senzorne osobine. Izvesni stepen pozitivnog uticaja ispoljen je u pogledu randmana mesa i prosečne telesne mase pastrmki posle ezenteracije

Evaluation of environmental conditions by fish hematology

In the work are shown basic principles of application of the haematological status in determination of physiological status of fishes, also a review of a number of research from this area is given. One part of the research includes analysis of parametres of hematological status of the individuals in their natural habitat, while the other part is focused on the research of these parametres in experimantal conditions based on changes of some of the factors. Review include erythrocyte line parameters (erythrocyte number, hemoglobin concentration, hematocrit, MCV, MCH and MCHC) in different conditions in species: Barbus balcanicus, Sqalius cephalus, Thymallus thymallus, Oncorhynchus mykiss, Carassius gibelio, Perca fluviatilis, Cyprinus carpio

High frequency of the R75Q CFTR variation in patients with chronic obstructive pulmonary disease

AbstractWe performed the complete screening of the CFTR gene in a group of 31 patients with COPD in order to investigate the impact of mutations and polymorphisms in the CFTR gene. The cumulative frequency of CFTR mutations (17.74%) was significantly higher than in our general population (P<0.0001). The R75Q was significantly overrepresented in COPD patients (8.06%; P=0.002). In all patients carrying the R75Q chronic bronchitis was a dominant symptom of COPD, and all were homozygous for the V470 allele. These findings suggest that R75Q mutation could be characteristic CFTR variant for COPD patients