Formativno proveravanje - podrška učenju hemijskih pojmova formativno naspram sumativnog proveravanja

The formative assessment as part of the instructional process of chemistry is presented. When incorporated into classroom practice, formative assessment informs both teachers and students about student understanding and help to ensure that students achieve learning goals and education standards within a given time frame. Since formative assessments are considered as part of the learning, they need not to be graded as summative assessments do. Formative assessments guide teacher decision making about future instruction and provide feedback to students, so they can improve their performance.Ovaj članak govori o proveravanju čiji cilj nije ocenjivanje ukupnog postignuća učenika nakon određenog perioda učenja, već je deo procesa učenja. Da li je takav pristup ugrađen u proces nastave i učenja hemije?

Potential Use of Essential Oils against Ovine Gastrointestinal Nematodes - Perspectives and Barriers

Ekonomski gubici koje gastrointestinalne nematode nanose modernom ovčarstvu postaju sve veći usled razvoja rezistencije na sintetske antihelmintike koji se koriste u svakodnevnoj kliničkoj praksi. Zbog toga, istraživači širom sveta, danas tragaju za alternativnim metodama u cilju kontrole ovih parazita. Kao moguća opcija su se zbog svojih osobina, nametnula etarska ulja i biljni proizvodi bogati različitim prirodno aktivnim jedinjenjima. Naime, prema dosadašnjim ispitivanjima, etarska ulja ispoljavaju visoku aktivnost protiv različitih razvojnih stadijuma nematoda, a uz pravilan način primene se generalno dobro tolerišu od strane sisara sa toksikološke strane gledišta. Do sada je dokazana visoka efikasnost velikog broja etarskih ulja protiv gastrointestinalnih nematoda ovaca (različite vrste eukaliptusa, limunske trave, mente, čajevca, timijana, cimeta, đumbira, lavande, crnog pelena i ruzmarina), njihovih aktivnih sastojaka (timol, karvakrol, karvon, anetol, mentol, cinamaldehid, cineol, linalol, vanilin, eugenol, limonen) kao i njihovih kombinacija (npr. cinamaldehid:karvakrol; anetol:karvon) u laboratorijskim uslovima. Međutim, glavno ograničenje za njihovu svakodnevnu primenu predstavlja još uvek nedovoljna efikasnost u terenskim uslovima, a koja potiče od anatomsko-fizioloških specifičnosti vezanih za preživare, kao i od farmakokinetičkih osobina pojedinih etarskih ulja. Ovaj problem bi se mogao prevazići odabirom odgovarajućih etarskih ulja uz adekvatno doziranje, način primene i formulaciju samih ulja, kombinovanom sinergističkom primenom više ulja ili njihovih sastojaka, kao i primenom nanotehnologije. Nevezano za ovaj problem, etarska ulja svakako imaju potencijal da uz kombinaciju sa drugim lekovima i merama, budu deo integrisanog pristupa, dizajniranog da se postigne održiva kontrola parazita u sistemima proizvodnje preživara. Potrebna su dodatna ispitivanja u ovoj oblasti, što se posebno odnosi na istraživanje efikasnosti u terenskim uslovima.The economic losses caused by gastrointestinal nematodes to modern sheep farming are increasing due to the development of resistance to regular anthelmintics used in everyday clinical practice. Therefore, researchers around the world nowadays are looking for alternative methods to control these parasites. Essential oils, herbal products rich in various naturally active compounds, have become a viable option because of their properties. Namely, according to the previous research, essential oils show high activity against all nematode development stages and are generally well tolerated by mammals from the toxicological point of view. So far, high efficacy of a large number of essential oils against sheep gastrointestinal nematodes have been demonstrated (different species of eucalyptus, lemongrass, mint, tea tree, thyme, cinnamon, ginger, mugwort, rosemary etc), their active compounds (thymol, carvacrol, carvone, anethole, menthol, cinnamaldehyde, linalool, vanillin, eugenol, cineole, limonene) as well as their combinations (e.g. cinnamaldehyde:carvacrol; anethole:carvone). However, the main limitation for their everyday use is still insufficient efficacy in field conditions, which originates from the anatomical and physiological specificities associated with ruminants, as well as from the pharmacokinetic properties of certain essential oils. This problem could be overcomed by selecting the appropriate essential oils with adequate dosage, method of application and formulations of oils, by combined synergistic application of multiple oils or their ingredients, as well as the using of nanotechnology. Regardless of this problem, essential oils certainly have the potential to be, in combination with other drugs and measures, part of an integrated approach designed to achieve sustainable parasite control in ruminant production systems. Nevertheless, further examinations on this topic are needed, especially of testing efficacy in field conditions

The Effect of Age on the Concentration of Total Protein, Albumin and Globulin in the Blood Plasma of Chickens

Промене у концентрацији укупних протеина, као и појединачних концентрација албумина и глобулина у крвној плазми често указују на присуство одређених обољења код птица. Међутим, до ових промена може доћи и услед дејства различитих физиолошких фактора, због чега их је неопходно идентификовати и испитати њихов утицај. Циљ овог истраживања је био испитати промену наведених биохемијских параметара у зависности од узраста пилића током производног циклуса (1-42. дан). За овај оглед су коришћени товни хибриди пилића (н=90) који су подељени у три групе у зависности од испитиваног параметра. Унутар сваке групе пилићи су подељени у неколико подгрупа у зависности од узраста (1., 3., 7., 14., 21. и 42. дан). Сви биохемијски параметри су одређивани квантитативном спектрофотометријском методом у лабораторији за биохемију на Пољопривредном факултету у Новом Саду. Раст концентрације албумина је био статистички значајан (п<0,05) између 1. дана (17,41 г/Л) и 3. дана (20,10 г/Л), и наставио се до 14. дана (21,58 г/Л), након чега је стагнирао до краја производног циклуса са забележеном вредношћу од 21,47 г/Л 42. дана. Значајан раст концентрације албумина у прва три дана живота се може објаснити повећаном синтезом албумина у јетри у том периоду. Са друге стране, услед губитка наслеђених имуноглобулина, концентрација глобулина је опадала до 14. дана (26,87 г/Л), такође статистички значајно (п<0,05) у прва три дана (30,42-28,25 г/Л), да би након 14. дана уследио пораст до краја производног циклуса (31,47 г/Л 42. дана) услед продукције антитела од стране пилића. Због оваквих промена у концентрацијама поменутих фракција, концентрација укупних протеина је током целог производног циклуса била у благом порасту (47,83-52,93 г/Л). На основу добијених резултата се може закључити да је узраст један од фактора који утиче на протеински систем крвне плазме птица, што се мора узети у обзир приликом тумачења резултата у свакодневној клиничкој пракси.Changes in the total protein concentration, as well as changes in individual concentrations of albumin and globulin in blood plasma often indicate the presence of certain diseases in birds. However, these changes can also occur due to various physiological factors, which is why they need to be identified and why their influence must be examined. The aim of this study was to examine the change in these biochemical parameters depending on the age of the chickens during the production cycle (day 1-42). Fattened hybrids of chickens (n=90) were used for this experiment, which were divided into three groups depending on the selected parameter. Within each group, the chickens were divided into multiple subgroups depending on age (the 1st, 3rd, 7th, 14th, 21st and 42nd day of age). All biochemical parameters were determined by the quantitative spectrophotometric method in the laboratory of biochemistry at the Faculty of Agriculture in Novi Sad. The increase of the albumin concentration was statistically significant (p<0.05) between day 1 (17.41 g/L) and day 3 (20.10 g/L), and continued to rise up to day 14 (21.58 g/L), after which it entered stagnation by the end of the production cycle with a recorded value of 21.47 g/L on day 42. The significant increase in albumin concentration in the first three days can be explained by the increased synthesis of albumin in the liver during that period. In comparison, due to the loss of inherited immunoglobulin, the globulin concentration was decreasing up to day 14 (26.87 g/L), also at a statistically significant rate (p<0.05) in the first three days (30.42-28.25 g/L). That was followed by an increase up to the end of the production cycle after day 14 (31.47 g/L on day 42) due to the production of antibodies by the chickens. Due to such changes in the concentrations of the mentioned fractions, the total protein concentration was slightly increasing during the entire production cycle (47.83-52.93 g/L). Based on the obtained results, it can be concluded that age is one of the factors which influence the protein system of avian blood plasma. As such, it must be taken into account when interpreting results in everyday clinical practice

Chemical Composition of Essential Oils and Compounds with Anthelmintic Potential

Neracionalna upotreba komercijalnih antihelmintika je dovela do razvoja antihelmintičke rezistencije kod mnogih vrsta endoparazita domaćih životinja. Zbog toga se intenzivno istražuju potencijalne alternative, među kojima često i etarska ulja različitih biljaka. Etarska ulja predstavljaju sekundarne metabolite biljaka sa veoma složenim hemijskim sastavom koji najčešće obuhvata veliki broj jedinjenja različitih hemijskih grupa. Najčešće su u pitanju različita terpenska, terpenoidna ili fenilpropanoidna jedinjenja od kojih je veliki broj i identifikovan, pri čemu je važno napomenuti da hemijski sastav etarskih ulja može da varira u zavisnosti od mnogo endogenih i egzogenih faktora. Poznata su mnogobrojna lekovita svojstva etarskih ulja, među kojima i antimikrobno, antiinflamatorno, antioksidativno dejstvo, zbog čega su ovi biljni proizvodi svoju primenu našli u terapiji mnogobrojnih oboljenja. U različitim in vitro i in vivo ispitivanjima je kod mnogih etarskih ulja dokazan i antihelmintički potencijal, a koji potiče od različitih jedinjenja koja ulaze u njihov sastav. Među ovim sastojcima se posebno ističu karvakrol, timol, anetol, cinamaldehid, karvon, limonen, pinen, terpinen, kariofilen, cimen, linalool, geraniol, mentol, borneol, citral, kamfor, eukaliptol, eugenol i mnogi drugi. Njihov izolovani antihelmintički potencijal je takođe potvrđen u mnogim istraživanjima, a ispitane su i njihove različite sinergističke kombinacije. Prisustvo velikog broja jedinjenja sa različitim mehanizmom delovanja pored efikasnosti govori u prilog i manjoj mogućnosti razvoja rezistencije kod samih parazita, a s obzirom da su u pitanju prirodni preparati, i manjoj toksičnosti za životinje u poređenju sa sintetskim preparatima. Zbog toga etarska ulja i njihovi sastojci predstavljaju obećavajuću alternativu u rešenju problema antihelmintičke rezistencije.The irrational use of commercial anthelmintics has led to the development of anthelmintic resistance in many species of domestic animals endoparasites. Therefore, potential alternatives, such as the essential oils of various plants, are being intensively explored. Essential oils are secondary metabolites of plants with a very complex chemical composition that usually includes a large number of compounds of different chemical groups. These are usually various terpene, terpenoid or phenylpropanoid compounds, many of which have been identified, whereby it is important to note that the chemical composition of essential oils can vary depending on many endogenous and exogenous factors. There are numerous documented medicinal attributes of essential oils, including antimicrobial, anti-inflammatory and antioxidant effects, which is why these herbal products have found their application in the treatment of many diseases. In various in vitro and in vivo examinations, essential oils have been shown to have anthelmintic potential, which originates from various compounds that are part of their chemical composition. Among these ingredients, carvacrol, thymol, anethole, cinnamaldehyde, limonene, pinene, terpinene, caryophyllene, cymene, linalool, gernaiol, menthol, borneol, citral, camphor, eucalyptol, eugenol and many others stand out. Their isolated anthelmintic potential has also been confirmed in many studies, and their various synergistic combinations have been investigated. In addition to an increase in efficiency, the presence of a large number of compounds with different mechanisms of action can contribute also to less possibility of the development of resistant helminth strains. Also, the natural origin of essential oils can contribute to their less toxicity to animals compared to synthetic preparations. Therefore, it can be concluded that essential oils and their ingredients represent a promising alternative in combating anthelmintic resistance

An Overview of the Most Important Methods for Examination of the Efficacy of Anthelmintics and Detection of Anthelmintic Resistance

Нерационална примена комерцијалних антихелминтика је довела до развоја антихелминтичке резистенције (АР) код многих врста ендопаразита домаћих животиња. То је довело до смањења ефикасности лекова из група бензимидазола, имидазотиазола и макроцикличних лактона и, последично, до великих економских губитака. Због тога је један од најважнијих приоритета модерног сточарства борба против АР, а која укључује примену адекватних in vitro и in vivo метода за њену детекцију. In vitro методе се заснивају на испитивању утицаја различитих концентрација одређене активне супстанце на одређене изоловане стадијуме паразита у лабораторијским условима. Међу њима су најосетљивије и најчешће коришћење методе тзв. egg hatch assay (EHA) и larval development assay (LDA). Са друге стране, in vivo методе као што је тзв. faecal egg count reduction test (FECRT), подразумевају испитивање утицаја препарата на паразите у самим животињима у теренским условима, где се ефикасност неког лека мери запаженом редукцијом броја одређених паразитских облика након третмана. Свака од наведених метода има своје предности и недостатке, због чега постоје стални напори да се усавршаве и стандардизују. У последње време се у контексту детекције АР све више испитују и користе различите молекуларне технике као што су PCR и пиросеквенцирање. Такође, важно је напоменути да се in vitro и in vivo тестови могу користити и за откривање нових супстанци као што су нека природна једињења са антихелминтичким потенцијалом, као и за испитивање њихове ефикасности. Из свега наведеног се може закључити да наведене методе имају вишеструки значај у борби против антихелминтичке резистенције.The irrational use of commercial anthelmintics has led to the development of anthelmintic resistance (AR) in many species of endoparasites commonly found in domestic animals. This has led to a decrease in the efficiency of drugs from the groups of benzimidazoles, imidazothiazoles and macrocyclic lactones and, consequently, to major economic losses. Therefore, one of the most important priorities of modern animal husbandry is to combat AR, which includes the application of adequate in vitro and in vivo methods for its detection. In vitro methods are based on examining the influence of different concentrations of a certain active substance on certain isolated parasitic stages in lab conditions. Among them, the most sensitive and the most common used methods are the egg hatch assay (EHA) and the larval development assay (LDA). On the other hand, in vivo methods such as the faecal egg count reduction test (FECRT), examine the effect of drug preparations on parasite-infected animals in field conditions, whereby the efficiency of a drug is measured by the observed reduction in the number of certain parasitic forms post-treatment. Each of these methods has its advantages and disadvantages, and efforts are regularly made to improve and standardize them. Recently, in the context of AR detection, various molecular techniques such as PCR and pyrosequencing have been increasingly examined and used. It is also important to note that in vitro and in vivo tests can also be used to detect new substances such as certain natural compounds with anthelmintic potential, and can be simultaneously used to test their efficiency. From the above-mentioned points, it can be concluded that these methods have multiple significance in combating anthelmintic resistance

Examination of the Efficacy of Fluralaner against Poultry Red Mite - Dermanyssus gallinae

Црвена кокошија гриња (lat. Dermanyssus gallinae) представља једног од најзначајнијег паразита модерног живинарства који причањава велике штете. Услед недовољне ефикасности и развоја резистенције према досадашњим акарицидима, проблем је постао још већи, због чега се јавила потреба за проналаском нове активне супстанце која ће ставити под контролу овог паразита. Флураланер, активна супстанца из групе изоксазолина, примењен у дози 0,5 mg/kg t.m., двократно у размаку од 7 дана се наметнуо као могућа опција. Према досадашним истраживањима, флураланер поседује изузетно високу ефикасност и брзину паразитицидног дејства против Dermanyssus gallinae у трајању од најмање три недеље, а такође утиче и на репродуктивни циклус гриња. При свему томе је знатно ефикаснији од осталих, постојећих акарицида. Поред тога, утиче и на повећање производње јер третирање заражених јата флураланером побољшава недељну стопа полагања код кока носиља. Међутим, с обзиром на ограничен број података у досадашњој литератури, потребна су додатна испитивања како би се потврдили досадашњи резултати, а флураланер треба примењивати заједно са другим мерама контроле Dermanyssus gallinae.Poultry red mite (lat. Dermanyssus gallinae) is one of the most important parasites of modern poultry that causes great damage. Due to inadequate efficacy and development of resistance to previous acaricides, the problem has become even greater, which has led to the need to find a new active substance that will put red mite under control. Fluralaner, as an active substance from the group of isoxazoline, administered at a dose of 0,5 mg/kg b.w., twice at the 7-day interval was imposed as a possible option. According to recent research, the fluralaner possesses extremely high efficacy and speed of parasitic kill against Dermanyssus gallinae for at least 3 weeks and also affects the reproductive cycle of mites. In all this, it is significantly more efficient than the other existing acaricides. In addition, it also affects the increase in production because the treatment of infected flies with fluralaner improves the weekly rate of laying on laying hens. However, given the limited number of data in the literature so far, further tests are needed to confirm the results, and the fluralaner should be applied along with other control measures of Dermanyssus gallinae

Occurrence of infectious laringotracheitis on farms in Vojvodina

For over 10 years infectious laringotracheitis has occurred rarely in Vojvodina. In such situations morbidity was 40% and mortality was 16%. Drop in egg production was over 30% and after 4 weeks egg production returned to normal. After the disappearance of clinical symptoms and after 30 days of quarantine and disinfection of eggs with formaldehyde and 5% hydrogen peroxide there was no appearance of the disease in hatched chickens. Clinical observation and pathohistology results are valuable proof for diagnosis of ILT. Diagnosis of ILT should be confirmed by virus isolation or applying serological tests such as ELISA on sera from diseased chickens

Co2 Emissions Trading at the Stock Exchange – Quality Enhancement of Tourism Potential, Ecological and Economic Growth

Since climate changes have caused significant problems in the functioning of the modern world, human society and economics at the global level, it is inevitable to take appropriate protective measures. Climate change and its bad influence directly relate to the environment and indirectly to economic, i.e. tourist activities which are linked to natural potentials. For years, human or industrial activities have been emitting greenhouse gases into atmosphere, which have harmed the climate to a large extent. In order to prevent further pollution, permits for emitting greenhouse gases were introduced at various conferences on a global level. These permits are traded on the stock exchange so this paper gives an overview and description of CO2 emission trading. Such an indirect environmental protection provides the possibility of reducing harmful gasses emission into atmosphere, and thus less harming climate factors. The paper puts emphasis on the Kyoto Protocol, CO2 emissions market, situation and tendencies on the market and their influence on tourism