Razvoj liderskih veština za efektivno upravljanje promenama u malim i srednjim preduzećima

Značaj liderstva i lidera u malim i srednjim preduzećima u dobu znanja i promena, je velika. Često se veruje da se lideri „rađaju“ i da se neko ne može naučiti da bude lider, ako za to nije predodređen, međutim, to je totalno pogrešno mišljenje. Naučne, tehničko-tehnološke i društvene promene značajno utiču i na promene u malim i srednjim preduzećima i liderstvu. Preduzeća i lideri moraju da prate i promene u obrazovanju. Biće važno ne samo učenje, već i procesi kako da se: uči, napreduje, bude kreativan i komunikativan. Prethodno i buduće obrazovanje lidera, značajno utiču na podizanje nivoa: znanja, veština razumevanja i veština motivacije lidera, a direktno utiču i na unapređenje poslovne komunikacije i prihvatanje poslovnih promena u malim i srednjim preduzećima. Sve to navedeno uz pravilno vođenje, značajno utiče na timski rad i poslovne konflikte vezane za slobode i pravednost u liderskom odlučivanju u malim i srednjim preduzećima. Takođe, sve se to odražava na kvalitet poslovnih procesa i poslovne performanse vezane za kvalitet života i produktivnost malih i srednjih preduzeća. U disertaciji je postavljen teorijski tzv. osnovni strukturni sistemski model iz koga je analizom i procenjivanjem 54 međunarodna eksperata, izveden novi strukturni sistemski model koji opisuje i rešava problematiku razvoja liderskih veština za efektivno upravljanje promenama u malim i srednjim preduzećima. Održivost postavljenog strukturnog sistemskog modela potvrdila se na analizi 140 malih i srednjih preduzeća u Srbiji. Dobijeni strukturni sistemski model je dinamičan i može se u skladu sa specijalnim zahtevima modifikovati. Vrlo je pogodan za eksperimentisanje i može pomoći u razvoju liderstva i poslovnih performansi malih srednjih preduzeća. U istraživanju je dokazano da je kvalitetan obrazovan lider pokretač unapređenja poslovnih performansi malih i srednjih preduzeća i da veštine lidera značajno utiču na prihvatanje poslovnih promena u malim i srednjim preduzećima.Small and medium-sized enterprises leadership importance in the knowledge and change era is significant. Wrong opinion that leaders becomes by „act of born“, and a leadership role is his destiny was widely accepted. Scientific, technical, technological and social changes significantly affect changes in SMEs and leadership. Companies and leaders need to follow the education process changes. In future it will be important not only to learn, but also the processes of how to: learn, advance, be creative and communicative. Previous and future education leaders, significantly raise the level of: knowledge, skills, understanding and motivation skills, as well as direct impact on business communication improvement and business changes acceptance in small and medium-sized enterprises. All this is stated with proper management, significantly affects teamwork and freedom related business conflicts as well as ethical decision-making in small and medium-sized enterprises. Also, all of this is reflected in the business processes quality and life and quality productivity related business performance of small and medium enterprises. Basic structural system model is set in Dissertation. Analysis and assess of 54 international experts attitudes, designed a new structural system model in order to solve the effective change management skills development in small and medium-sized enterprises. Proposed structural system model sustainability was verified by analysis conducted on 140 small and medium-sized enterprises in Serbia. The resulting structural system model is dynamic and can be modified in accordance to special requirements. It is sutable for experimentation and can be useful in small medium enterprises leadership and business performance development. The study proved: that a educated leader is the initiator small and medium-sized enterprises of business performance improvement. Besides, leader skills significantly influence on business changes acceptance in the SMEs

Uticaj kadmijuma na klijanje semena i rast pšenice

In this study, the effect of Cd on the germination, growth of seedlings and composition of plants deriving from contaminated grains, grown in the field, was examined. Wheat grains were soaked in Cd-containing solutions: 0 (control, deionized water), 10-5 , 10-4 , 10-3 , and 10-2 M CdCl 2 during 24h. One portion of grains was used to test germination and seedling growth, while the other was sown in the field. The concentration of Cd in the grains almost linearly increased with the increase in the applied concentrations of Cd, which reduced the germination and energy of germination and increased the proportion of atypical seedlings. Larger concentrations of Cd significantly impaired the growth of seedlings (length of the shoots and roots, dry matter mass). In the grains of the field-grown plants the concentrations of N, P, and K were not affected by Cd, but their concentrations in the straw declined (especially of N). These results suggest that the emergence and development of plants on the soil polluted by Cd are likely to be significantly limited and yield reduced.Kadmijum (Cd) je potencijalni zagađivač sredine živih organizama i pri većim koncentracijama odlikuje se jakim fitotoksičnim dejstvom. U radu je u laboratorijskim uslovima proučeno dejstvo različitih koncentracija kadmijuma na klijanje i rast mladih biljaka pšenice, a u poljskim uslovima njegov uticaj na koncentraciju mineralnih materija u zrnu i slami u fazi pune zrelosti biljaka, koje su potekle od zrna tretiranog kadmijumom. S povećanjem koncentracije kadmijuma u fazi bubrenja semena skoro se linerano povećala njegova koncentracija u semenu. Utvrđeno je da veće koncentracije kadmijuma značajno smanjuje klijanje i energiju klijanja semena, a povećavaju učešće atipičnih klijanaca i neproklijalog semena. Veće koncentracije kadmijuma značajno su smanjile rast mladih biljaka kao i masu njihove suve materije. Rast nadzemnog dela i korena smanjen je u većoj meri od mase suve materije, na osnovu čega se može zaključiti da je kadmijum u većoj meri uticao na faktore rasta nego na stvaranje suve mase. Najveća primenjena koncentracija kadmijuma smanjila je hidratisanost 68 nadzemnog dela mladih biljaka. Bubrenje semena u prisustvu različitih koncentracije kadmijuma nije uticalo na koncentraciju azota, fosfora i kalijuma u zrnu, a smanjilo je njihovo prisustvo u slami, naročito azota na kraju vegetacije. Dobijeni rezultati potvrđuju nalaze ranijih istraživanja kod drugih biljnih vrsta na osnovu kojih su fiziološki i biohemijski procesi klijanja semena značajno inhibirani u prisustvu većih koncentracija kadmijuma. Na osnovu navedenog može se predvideti da će na zemljištu zagađenom kadmijumom nicanje useva i rast mladih biljaka pšenice biti ograničeno, što će se nepovoljno odraziti na prinos useva

ABA Triblock Brush Polymers: Synthesis, Self-Assembly, Conductivity, and Rheological Properties

The synthesis, self-assembly, conductivity, and rheological properties of ABA triblock brush polymers (BBCPs) with grafted polystyrene (A block, N_(PS) = 21) and poly(ethylene oxide) (B block, N_(PEO) = 45) side chains are reported. Two backbone molecular weights (N_A:N_B:N_A = 11:78:11 and 15:119:15) were investigated with lithium bis(trifluoromethane)sulfonimide (LiTFSI) doping ratios 2 ≤ [EO]:[Li+] ≤ 20. Blends with 2 ≤ [EO]:[Li+] ≤ 10 suppress PEO crystallization and self-assemble into hexagonally packed cylinders of the minority gPS component. Conductivity is on the order of 10^(–3) S/cm at 105 °C with a corresponding elastic modulus ca. 10^4 Pa. The optimum conductivity occurs at a blend ratio near 10:1 [EO]:[Li+], similar to that reported for linear block copolymer analogues

Odnos koncentracije zemnoalkalnih metala kalcijuma, barijuma i stroncijuma u zrnu diploidne, tetraploidne i heksaploidne pšenice

Even though calcium (Ca), strontium (Sr) and barium (Ba) belong to the same group of the periodic table of elements, and thus have similar chemical features, their importance for plants differs greatly. Since plants do not have the ability to completely discriminate between essential (e.g. Ca) and non-essential elements (e.g. Sr and Ba), they readily take all of them up from soil solution, which is reflected in the ratios of concentrations of those elements in plant tissues, and it influences their nutritive characteristics. The ability of plant species and genotypes to take up and accumulate chemical elements in their different tissues is related to their genetic background. However, differences in chemical composition are the least reflected in their reproductive parts. Hence, the aim of this study was to evaluate ratios of concentrations of Ca, Sr and Ba in the whole grain of diploid and tetraploid wheat ‒ ancestors of common wheat, as well as in hexaploid commercial cultivars, grown in the field, at the same location, over a period of three years. The investigated genotypes accumulated Ca, Sr and Ba at different levels, which is reflected in the ratio of their concentrations in the grain. The lowest ratio was established between Ba and Sr, followed by Ca and Ba, while the highest ratio was between Ca and Sr. Moreover, the results have shown that the year of study, genotype and the combination highly significantly affected the ratio of the concentration Ca:Sr, Ca:Ba, and Ba:Sr.Kalcijum (Ca), stroncijum (Sr) i barijum (Ba) pripadaju istoj grupi elemenata Periodnog sistema i imaju slične hemijske osobine. Međutim, njihove uloge u biljnom organizmu veoma se razlikuju. Obzirom da biljke nemaju sposobnost da u potpunosti razlikuju esencijalne (C a) od neesencijalnih elemenata (Sr i B a), one ih sve usvajaju iz zemljišnog rastvora, a to se odražava u različitom odnosu koncentracija ovih elemenata u biljnom tkivu i utiče na njihove nutritivne osobine. Sposobnost vrsta i genotipova da usvajaju i akumuliraju hemijske elemente u različitim tkivima, zavisi od njihove genetike. I pored toga, razlike u hemijskom sastavu ogledaju se u njihovoj reproduktivnoj ulozi. Cilj istraživanja bio je da se odrede odnosi koncentracija Ca, Sr i Ba u celom zrnu diploidne i tetraploidne pšenice - pretka današnje pšenice, kao i heksaploidnih komercijalnih vrsta, gajenih na istom polju i lokalitetu tokom tri godine. Ispitivani genotipovi su akumulirali Ca, Sr i Ba u različitim količinama, što se odrazilo na odnos njihovih koncentracija u zrnu. Najniži odnos ustanovljen je između Ba i Sr, zatim Ca i Ba, a najveći između Ca i Sr. Takođe, rezultati su pokazali da godina ispitivanja , genotip i kombinacija značajno utiču na odnos koncentracije Ca:Sr, Ca:Ba i B a:Sr

Dehydration-related changes of peroxidase and polyphenol oxidase activity in fronds of the resurrection fern Asplenium ceterach L.

Asplenium ceterach belongs to a group of poikilohydric ferns and it can recover uninjured from an almost completely dehydrated state. In our study, short term dehydration (24h) at four different water potentials, resulted in moderate water loss (partial desiccation) in fern tissue. The main phenolic acids represented in A. ceterach were chlorogenic (CGA) and caffeic acid (CA) and their content decreased during the dehydration process. For the first time, peroxidase (POD) and polyphenol oxidase (PPO) isoforms were determined in the rustyback fern. The results exhibit the presence of numerous anionic POD isoforms, with pI ranging from 4.4 to 5.8, but none of the cationic isoforms was detected. Two PPO isoforms were identified, one anionic with pI 6.3 and one cationic with pI of about 9.0. Short-term dehydration brought about a remarkable increase in POD and PPO activity using CGA as a substrate. Changes in enzyme activity and content of substrates during dehydration may play an important role in the adaptation of the rustyback fern to water deficit, and increase the overall plant resistance to stress conditions.nul

Removal of cationic dye from water by activated pine cones

Adsorption of a cationic phenothyazine dye methylene blueonto activated carbon prepared from pine cones was investigated with the variation in parameters of contact time, dye concentration and pH. The kinetic data were found to follow the pseudo-second-order kinetic modelclosely. The equilibrium data were best represented by the Langmuir isotherm with maximum adsorption capacity of 233.1 mg g-1. Adsorption was favored by using a higher solution pH. Textural analysis by nitrogen adsorption was used to determine specific surface area and pore structure of the obtained carbon. Boehm titrations revealed that carboxylic groups are present in the highest degree on the carbon surface. The results indicate that the presented method for activation of pine cones could yield activated carbon with significant porosity, developed surface reactivity and considerable adsorption affinity toward cationic dye methylene blue

Fiziološka osnova prinosa ječma u optimalnim uslovima i uslovima suše

Average barley yield fall below its potential due to incidence of stresses. Water stress is the main environmental factor limiting yield. The component a priori more sensitive to most stresses is the amount of radiation absorbed. The effect of stresses influence on the total amount of radiation absorbed by barley crop during its vegetation and the photosynthetic efficiency of radiation conversion. Growth inhibition is accompanied by reductions in leaf and cell wall extensibility. Grain yield under drought conditions is source limited. Supply of assimilates to the developing inflorescence plays a critical role in establishing final grain number and grain size. Grain weight is negatively affected by drought, high temperature, and any other factors that may reduce grain filling duration and grain filling rate. Awns and glaucousness confer better performance of barley under drought stress conditions. Barley responds with an increased accumulation of a number of proteins when subjected to different stress inducing cell dehydration. Screening techniques that are able to identify desirable genotypes based on the evaluation of physiological traits related to stress evasion and stress resistance maybe useful in breeding barley for resistance to stress, particularly drought stress. Crop management and breeding can reduce the incidence of stress on yield. The effect of these practices is sustained by an understanding of their physiology. In this paper the physiological basis of the processes determining barley yield and the incidence of stresses on photosynthetic metabolism that determine grain yield of barley is discussed. .Prinos ječma je najčešće niži od njegovog proizvodnog potencijala zbog delovanja niza nepovoljnih biotičkih i abiotičkih činilaca, čije se negativno delovanje naziva stres. Deficit vode je najčešći uzrok smanjenja prinosa. Stres se prvenstveno manifestuje u smanjenju apsorbovane sunčeve energije tokom vegetacije i efikasnosti njene konverzije, što dovodi do smanjenja raspoloživih asimilata i formiranja ukupne biomase i prinosa zrna. Raspoloživi asimilati imaju ključnu ulogu u formiranju sve tri komponente prinosa; broja klasova po jedinici površine, broja zrna po klasu i mase zrna. Stvaranje genotipova tolerantnih na stres i primena odgovarajuće tehnologije proizvodnje predstavlja osnovne načine suprotstavljanja stresu. U radu je dat prikaz fiziološke osnove procesa koji određuju prinos ječma i uticaj činilaca stresa, posebno deficita vode, na biološki i ekonomski prinos ječma.

Heavy Metals Content in Selected Medicinal Plants Produced and Consumed in Serbia and Their Daily Intake in Herbal Infusions

The heavy metals content (HMs) was investigated in 14 different medicinal plants collected from the three regions in Central Serbia, Zlatar, Sokobanja, and Kopaonik. The concentrations of Cd, Cr, Ni, Hg and Pb were determined: Cd (<0.03–2.72 mg/kg); Cr (<0.08–12.1 mg/kg); Ni (<0.08–12.2 mg/kg); Pb (0.6–49.0 mg/kg); the Hg concentration was below the detection limit of 0.06 mg/kg in all samples. The daily intake of HMs due to ingestion of 200 mL of herbal infusion was in all cases below the recommended limit prescribed by the World Health Organization. The estimated daily intake values were below the values for the oral reference dose regulated by the U.S. Environmental Protection Agency (USA EPA). The target hazard quotient and hazard index for Cd, Cr Ni, and Pb were below 1. Nevertheless, due to the tendency of heavy metals to accumulate in the organism, attention should be paid to the daily intake of herbal infusion during long-term usage. Specifically, it is recommended to consume not more than one cup (200 mL) of infusion per day made from thyme (Mt. Zlatar) and blueberry (Mt. Kopaonik), and not more than two cups per day for other herbs

Copmarative analysis of mortars from the archeological sites Gamzigrad (Romuliana) and Caričin Grad for the purpose of making compatible repair mortars

The paper presents a comparative analysis of mortars found at two significant archeological sites in Serbia. Specifically, those are Gamzigrad (Romuliana) near Zajecar and the archeological site Caricin Grad near Leskovac. In the previous papers, we dealst with the characterization of mortars from both sites. It was the first examination of mortars from both locations. The comparative analysis of mortars was performed based on the data obtained by testing physical-mechanical properties such as: water absorption, porosity, gravity and specific mass. Mineralogical composition (both quantitative and qualitative) was obtained based on XRD / XRF and SEM/EDS analyses. The comparative analyses of the mortar obtained from the mentioned archeological sites indicated that mortars from both locations contained grains of river aggregate, crushed limestone aggregate and crushed masonry bricks. The share percentage varied. Regarding the binder, the mortar from the Gamzigrad (Romuliana) site had limestone used for the binder, while the mortar from the Caricin Grad site had clay and powdered masonry bricks. The obtained results of mortar analysis pave the way for further research with an aim of making repair mortars

DETERMINATION OF CRITICAL SIZE OF CORROSION PIT ON MECHANICAL ELEMENTS IN HYDRO POWER PLANTS

Researchers in the field of fracture mechanics, predominantly developing appropriate solution algorithms for problems of solid bodies with cracks. Problems in mechanics generally, related with fracture and fatigue for solid bodies with various geometries of sharp notches, are studied to a much lesser extent. This situation can be explained by analytical difficulties arising in solving problems of elasticity theory for bodies with rounded notches. To solve problems of such class, starting from data on stress concentration in the rounded notch tip with a significant radius of curvature, simplified solutions with are therefore of great importance. Recent years, due to constant rise of computing power and development of numerical methods, re-evaluation of stress concentration factors from a viewpoint of theory of elasticity is present. This is mainly as a feedback from industry, which have requirements toward mega and nanostructures. Corrosion represents an important limitation to the safe and reliable use of many alloys in various industries. Pitting corrosion is a form of serious damage on metals surface such as high-strength aluminum alloys and stainless steel, which are susceptible to pitting when exposed to a corrosive attack in aggressive environments. This is particularly valid for dynamic loaded structures. The basic idea behind this paper is finding links between different scientific and engineering disciplines, which will enable useful level of applicability of existing knowledge. The subject of this paper is application of new method of determine length scale parameter for estimating the mechanistic aspect of corrosion pit under uniaxial/multiaxial high-cycle fatigue loadin