In this study, concentrations of lead Pb, cadmium Cd and arsenic As were tested in 177 samples of fresh vegetables produced in the area of Zenica. This locality is exposed to the strong influence of high emissions of various pollutants primarily originating from metallurgical and thermal power plants, but also from local heating plants. The accumulation of heavy metals is followed by the types of vegetables: tuber and root, bulb, leaf, fruiting and legume from the group of fruiting vegetables. Preparation of samples was done with microwave digestion. The concentration of the selected metals in solutions after digestion was determined on Induced coupled plasma mass spectrometry (ICP-MS). The percentage participation of contents Pb, Cd and As, either higher or lower than the maximum allowable amount prescribed by the applicable law, was calculated in all 177 samples. The results showed that different groups of vegetables have different ability to adopt and accumulate heavy metals. The largest number of samples containing Pb content above the maximum level (ML) was in the group of leaf vegetables, then in the roots and finally in bulb groups. Cd was at the very limit with the maximum level in the parsley sample, while all other tested samples were in compliance with the applicable regulations. Two of the tested samples of the parsley leaves group had an increased content of As according to the legal regulations.

Uvod: Pedagoški rad, odnosno edukacija, u ustanovama odgoja i obrazovanja posebno u periodu ranog djetinjstva predstavlja temeljno djelovanje za razvoj pozitivnih navika i zdravih stilova života. Ranija pedagoška, a posebno longitudinalna istraživanja pokazala su kako predškolski odgoj, utjecaj obitelji i škole značajno doprinose razvoju higijenskih, zdravstvenih, ekoloških, kulturnih i emocionalnih navika kod djece. Smatra se da su predškolska i školska dob ujedno razdoblja koja stručnjaci definiraju kao vrijeme i pedagoško-odgojnu, obiteljsku i društvenu obavezu za prikladno započinjanje prevencije kroničnih bolesti odrasle dobi, u prvom redu kardiovaskularnih bolesti. Kroz pravilnu prehranu djeca zadovoljavaju svoje energetske potrebe, ali i unos vitamina i minerala. To znači da periodu njihovog razvoja treba prilagoditi prehranu, pa zato u vrtiće i škole treba uvesti promjene. Cilj rada: Istražiti pedagoške aspekte utjecaja pravilne prehrane na razvoj pozitivnih navika kod djece u školama kroz zastupljenost takvih sadržaja u nastavnim programima osnovnog obrazovanja Tuzlanskog kantona. Materijal i metode: Ovo presječno istraživanje provedeno je tijekom rujna 2015. godine na osnovu podataka dobivenih iz nastavnih planova i programa za osnovno obrazovanje na Tuzlanskom kantonu. Korištena je analitičko deskriptivna metoda i postupak analize sadržaja četiri nastavna predmeta: „Moja okolina“, „Biologija“, „Kemija“ i „Kultura življenja“. Ovi predmeti se uče na nivou druge i treće trijade osnovnog obrazovanja. Zaključak: Rezultati istraživanja ukazuju da je u devetogodišnjem osnovnom obrazovanju obuhvaćeno jedanaest predmeta koji obrađuju ili u sebi imaju zastupljene sadržaje koji tretiraju prehranu i zdrave stilove života djece u osnovnom obrazovanju. Važno je osvijestiti da je potrebna veća zastupljenost ovakvih sadržaja kroz nastavne predmete, kao i kontinuirana edukacija odgajatelja i nastavnika u području nutricionizma i ekologije te kulture o zdravom životu i razvoju mladih. Kao mjeru prevencije, predlaže se da nadležne stručne pedagoške službe i ministarstva hitno učine promjene u pogledu sadržaja nastavnih programa osnovnog obrazovanja kroz model izborne nastave koja će predvidjeti prehranu i zdrave stilove života kao važnu pedagošku djelatnost za razvoj mladih.

We present some basic discrete models in populations dynamics of single species with several age classes. Starting with the basic Beverton-Holt model that describes the change of single species we discuss its basic properties such as a convergence of all solutions to the equilibrium, oscillation of solutions about the equilibrium solutions, Allee’s effect, and Jillson’s effect. We consider the effect of the constant and periodic immigration and emigration on the global properties of Beverton-Holt model. We also consider the effect of the periodic environment on the global properties of Beverton-Holt model.

Constant changes in the market and technological advancements condition swift outdating of knowledge and require staff that is open to changes, flexible, proactive, and adaptable. Human resources required by travel agencies must have the basic knowledge of economy, geography, catering, transportation, consumer psychology, and must know at least one additional foreign language. Considering the fact that quality of service in tourism mostly depends on the interaction of the service providers and guests, it is expected of the employees to always smile, be polite, U D C 3 3 8 . 4 8 : 3 7 ( 4 9 7 . 1 1 ) D O I : 1 0 . 5 9 3 7 / t i m s a c t 1 1 1 4 1 9 6 P R E G L E D N I Č L A N A K 2017. Fakultet za sport i turizam, Novi Sad, TIMS Acta 11, 133-142

The paper analyzes customer satisfaction of mobile operators' services in Serbia and the way propaganda influences the creation of value for customers. Mobile operators are trying to be different from their competition in the delivery of services, relevance, creativity, and so on. In this way they are trying to attract more users. The mobile industry is developing rapidly, and new products and services appear almost daily. To keep users up to date with any developments in this industry, mobile operators must try to give them all of the new information presented at the right time, in a way that will interest them. The paper examines the benefits offered by operators, from the price to the benefits in the form of various gifts and discounts. The work is complemented by a survey based on the study of ways that should lead to improvements in customer satisfaction of current operators in Serbia.