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Proper selection of irrigation methods and rational use of water using the principles of precision agriculture and precision irrigation results in environmentally sustainable agricultural development. Subirigation is a method of irrigation with less water consumption, provides the possibility of automation and remote control of the system, allows for the smooth movement of agricultural mechanization along the irrigated parcel and has an extremely flexible irrigation schedule. The utilization of the subirrigation system complicates and limits drip clogging, soil salinization, and damage caused by rodents. In the case of regular flushing of pipelines and laterals, herbicides and acids are used to prevent root ingrowth and the plot is treated against rodents, the guaranteed exploitation lifetime of the system is 20 years. Subirrigation systems implemented in the Republic of Serbia are 1-130 ha in size and the total irrigated area is 1500-2000 ha.

When and how will one country take care of its workers who are left due to their injury, illness, death or old age without ability to care for their existence, and who contributed most of their life as tax payers. The role of the social system is just that. Social systems of intergenerational solidarity operate for decades in all European countries, regardless of their political and economic structure and level of development. Number of employees within a pension system is dependent on many factors, but it is also independent compared to the category of pensioners and possibilities of functioning of the pension system. The total number of beneficiaries directly derived from the number of employees in some earlier period, while the possibility of pension payments vary depending on the current number of workers. Some categories may behave differently in relation to the total number of employed in an economic system, but the functioning of the pension system is depending on this indicator. In Serbia, for years the number of deaths exceeded the number of births, large-scale migration of citizens, the progress of medical science as a factor of increased life expectancy of people, higher rates of unemployment, longer years of service until retirement and some other less significant factors influenced the disproportion in the number of employees in relation to the number of pensioners. This resulted in a very poor state of the pension system and caused the question of its future functioning. A social problem is getting more difficult to resolve, in quality and quantitative terms, because its main source of inflow of funds is in constant decline while expenditures are increased.

Food production is becoming very important and it receives priority in relation to other activities in the world. As the number of inhabitants of the planet grows, food production has greater significance. Its production will certainly be affected by climate changes and the potential of agricultural land, which will be followed by changes in insurance cover of crops. Total area of arable land doesn’t have the same quality, but it’s especially common for underdeveloped and developing countries is that arable land is not used in the appropriate percent. For Serbia which belongs to that group of countries with low yield on arable land, it can be pointed out that insurance does not cover a sufficient share of that area. The reason for this lies in the lack of trust of potential insured, habits and consciousness of the insured, economic policy pursued by the state in relation to this issue, inadequate training of insurance agents and the lack of proper insurance products.

Competitiveness in the international business environment is a key instrument of success and evaluation of created value of all participants in the value chain. It can be assessed using a variety of indicators, taking into account many factors affecting its complex structure. Hence, it is a framework affirming the competitive advantages/disadvantages on the macro and micro-level as well as on the level of companies and their product offer. Competitiveness can be analyzed at the levels of national economy, industrial sectors, as well as individual products level. The most common approach to the comparison of achieved competitiveness level relates to product costs and/or market price compared to quality (value) aspects of the product/service. Prices and the quality of inputs feature as the starting points for competitiveness of the national economy. Efficiency of operations recognizes the impact of all inputs, especially those whose relative share in the total production cost is high. In contrast to the highly automated production processes, agriculture remains a labour-intensive activity, despite the increase in the level of automation. It is an exception compared to other industries due to the high impact of the effects of climate and other natural factors productivity. At the same time, agriculture is a very important economic and social field of activity, and different concepts of macroeconomic measures are developed in different national economies to stimulate the balanced regional development of agricultural production. Macroeconomic factors that determine overall business environment for the development and competitiveness of agriculture have a very high level of impact on the competitiveness of agricultural products in the Republic of Serbia.

The global financial crisis has confirmed the global regulatory mechanism weakness in the prevention of the causes and consequences in stress situations. As an expression of inadequacy, Basel Committee designed Basel III standard as a new regulatory framework for banks. Its implementation involves the compliance of strict capital requirements, liquidity standards and leverage. Researches about the effects of Basel III standards indicate that a shorter time horizon, these are the consequences for economic growth is greater. For the four-year implementation period, the increase in capital requirements for the 1% would result in a reduction in global GDP by 0.1%, while the largest drop in GDP would be recorded after 18th quarter and amounted to 0.19%. Also, during the implementation horizon cross-country spillover effect will occur that would be stronger in developing countries relative to developed countries and amounted to 0.03%. Based on the above, pure effect of increasing capital requirements on the reduction of world GDP is estimated to 0.016%.

Small and medium enterprises are the backbone of the development of not only Serbia but also EU and many other countries. In recognition the importance of small business sector for economic development, keeping in mind the specificities of SME (small sales volume, modest amounts of capital, permanently 'tense' liquidity position) modalities of credit support to this sector, by definition, include the appropriate 'mix' of funds from commercial sources, from international sources, with the assistance of state regulation and support. Variants of credit support in Serbia range from purely commercial forms of credit through the participation of banks in the transfer of funds from public and international funds, to direct budget allocations and interest rate subsidies. Despite the massive credit support, SMEs in Serbia continue to face very tough lending conditions, that restrictive influence on the development of this sector.

The paper deals with a specific aspect of a general survey, that is being carried out during last ten years in several regions of Serbia (former Yugoslavia, former Serbia and Montenegro) to assess population exposure to natural radioactivity based on geochemical and integrative pattern research approach. The originality regarding this work is related to the facts such as follows: the first identification and assessment of high areas of natural radiation in Serbia which provides insight into its regional characteristics, the interpretation of the results in terms of geological aspects, building types and human habits, the first introduction and field applicability of both (surface and volume trap) retro techniques in Serbia and assessment of doses and risks to the population in investigated high natural radiation rural communities.

The first radon soil gas survey in Serbia, using passive detectors (SSNTD, CR-39), was carried out in June 2005 at field sites in Niska Banja town. The aim of the survey was to identify risk zones characterised by high levels of this radioactive gas. Radon measurements were made at the depth of 50 cm, in the ground according to a systematic grid pattern. Furthermore, at all 48 measurement points, the surface gamma dose rates in the air was also measured at the same locations and soil samples were collected for gamma spectrometric analysis for the radionuclides 226Ra, 228Th and 40K. Radon concentrations were found to range from 1270 to 155 000 Bq m - 3 with an average of 33 765 Bq m - 3 and a median value of 12 626 Bq m - 3 . The geometrical mean value and geometrical standard deviation were calculated as 16 160 Bq m - 3 and 3.5 Bq m - 3 , respectively. Gamma dose rate varies from 92 to 316 nGy h - 1 , with an average of 132 nGy h - 1 . The radium content in collected soil samples ranges from 24 to 1810 Bq kg - 1 with an average of 187 Bq kg - 1 . High correlations ( r 2 > 0.8 ) between soil gas radon concentration, gamma dose rate and 226Ra content in soil were found for each pair. The distribution of radon concentrations in soil gas shows bimodal shape.

Heavily calcified ascending aorta significantly increased morbidity and lethality during open-heart surgery. Cannulation and clamping (partial or total) of severely atherosclerotic ascending aorta can easily cause damage and rupture of aortic wall, with consequential distal (often fatal) embolization with atheromatous debris (brain, myocardium). From June 1998. until June 2000, 11 of 2 136 (0.5%) patients who underwent coronary artery bypass grafting were with the severe atheromatous ascending aorta. The site of cannulation was in the aortic arch in three patients (aorta was occluded with Foley catheter in one case, and single clamp technique was used in the other two cases). The femoral artery was the cannulation site in other five cases. Profound hypothermia, ventricular fibrillation, and circulatory arrest, with no cross-clamping or cardioplegia, were used in three patients. Two patients were operated on with extracorporeal circulation, one in normothermia, on the beating heart, the other in moderate hypothermia, on fibrillating heart. In three patients myocardial revascularization was performed on the beating heart, in normothermia, without extracorporeal circulation. Postoperative course was uneventful in all 11 patients. Neither atheroembolism in the peripheral organs, nor atheroembolism of the extramities occurred. The proposed surgical approaches have the potential to reduce the prevalence of stroke and systemic embolization associated with coronary artery bypass grafting in patients with heavily calcified ascending aorta. This result was achieved due to the applied modifications of standard cardiosurgical technique.

In vivo skull measurements of 210Pb have been performed to assess the individual, chronic exposures of two persons living for 28 years in a house with a distinctly enhanced radon concentration of more than 10,000 Bq/m3. A partial body counter consisting of 4 HPGe detectors, which were placed close to parietal positions of the head, was used in the study. The lower limit of detection of 210Pb activity in the skeleton was found to be 40 Bq. Lead-210 activities of up to 152 Bq were found in the test persons, whereas no activity could be measured in an unexposed control person. The cumulative uptake of 210Pb into the body was assessed for each single test person by using the ICRP respiratory tract and the biokinetic models. A fairly good agreement (within a factor of 2) between in vivo measurements and model was achieved for these two test persons. The technique used in the study may be a useful tool to evaluate assumptions, which have to be made for the reconstruction of individual, cumulative exposures to high radon concentrations.

Surgical closure of patent ductus arteriosus (PDA) is still required in selected adult patients. We analyzed the morphology of the anomaly and coexisting pathological findings in adult patients who were recently referred to our institute for surgical PDA repair.Six adult PDA patients who were not considered candidates for percutaneous closure underwent surgical PDA correction. In three patients with isolated PDA, computed tomographic scan revealed short, wide, and distorted ductus. In the remainder three patients, concomitant heart or aortic disease was found. Transpulmonary approach under total cardiopulmonary bypass or hypothermic circulatory arrest was performed.In all patients, a Dacron patch was used to close the duct. The balloon occlusion technique with normothermic cardiopulmonary bypass was performed in four patients. In one of these patients, the balloon occlusion was not feasible because of unfavorable ductal anatomy, and PDA was closed in short hypothermic circulatory arrest. In two patients with aortic aneurysm, PDA closure and aortic reconstruction were performed in deep hypothermic circulatory arrest. No significant complications occurred during postoperative course. After the mean follow-up period of 48 months, neither ductal reopening nor aneurysmal degeneration of remnant ductal tissue was found.Surgical PDA closure in adults remains the treatment of choice in wide, deformed PDAs unsuitable for percutaneous closure and PDAs associated with surgical aortic or heart disease.

The measurement campaigns have been done in the rural community of Niska. Banja, a spa town located in southern Serbia, to evaluate population exposure to natural radioactivity. After a screening survey in 200 houses, annual radon and thoron concentrations were measured in 34 houses, and in 2004 a detailed investigation was carried out at six houses with elevated indoor radon concentrations. The paper presents the results of these detailed measurements. The complementary techniques were applied to determine radon and thoron concentrations in indoor air, in soil gas, radon exhalation from soil, soil permeability, and indoor and outdoor gamma doses. Soil and water samples were collected and analysed in the laboratory. Indoor radon and thoron. concentrations were found to be more than 1 kBq m(-3) and 200 Bq m(-3) respectively. Extremely high concentrations of soil-gas radon ( GT 2000 kBq m(-3)) and radon exhalation rates (1.5 mBq m(-2) s(-1)) were observed. These results will be utilised to set up the methodology for a more systematic investigation. (c) 2006 Elsevier Ltd. All rights reserved.

Experimental studies of two fluid displacement processes in porous media involving extensive fragmentation of invasion percolationlike structures are described. In the first process, a two-dimensional porous cell saturated with a wetting fluid was slowly invaded by air. The air formed a fractal structure that fragmented when the pressure of the wetting fluid increased and the air was driven out of the system. In the second process, a fractal air structure migrated through a two-dimensional porous medium saturated with wetting fluid. The structure was driven by increasing buoyancy forces and fragmented. The fragments migrated, fragmented, and coalesced with other fragments. The processes were simulated using new site-bond invasion percolation models that captured the displacement mechanisms and reproduced the fragmentation events, and good agreement was found. In both processes, the fractal dimensionality of the fragments was equal to the dimensionality D\ensuremath{\approx}1.82 of the initial invasion percolationlike structures. The fragment size distributions measured in both processes and the dynamics of the migration process could be described by simple scaling forms.

Free trade has become a modern-day creed, accepted by both wealthy industrialized countries and many governments of developing countries as the generator of economic growth, development and employment. However, free trade has also been condemned by non-governmental organizations (NGOs) in developing countries as the tool through which the economic dominance of wealthy, developed countries is institutionalized and maintained. Agriculture has been one of the most controversial issues in the multilateral trade negotiations for the past fifty years. The aim of this article is to examine food security implications of the WTO Agreement on Agriculture. It discusses the WTO Agreement on Agriculture, which is systematically favoring agricultural producers in industrialized countries at the expense of farmers in developing countries, and explores ways in which the Agreement may be modified to achieve a more equal chance for success for both parties. The article also deals with the extent to which realization of the Agreement’s stated objective – the establishment of a fair and market-oriented agricultural trading system—is likely to advance food security in developing countries. The first section defines food security, discusses the relationship between trade and food security, and analyzes the impact of the WTO Agreement on Agriculture on food security in developing countries. The second section sets forth the reforms necessary to address inequities in the global trading system for agricultural commodities, and enhance and protect food security in developing countries. The last section concludes that leveling the playing field between industrialized and developing countries is a necessity, but not sufficient to promote food security. Promotion of food security requires additional trade reforms, so as to provide developing countries with a wide range of solutions and ensure access by all people at all times to sufficient, safe and nutritious food.

Two-phase fluid displacement in a two-dimensional porous medium has been studied experimentally and by simulations. A random porous medium was saturated with a wetting fluid (water/glycerol). A non-wetting fluid (air) was then slowly injected, forming a fractal invasion percolation-like structure. Shortly before breakthrough, the pressure of the wetting fluid was increased and the non-wetting fluid was forced to withdraw. The structure formed by the non-wetting fluid disintegrated into fragments. The displacement patterns were found to agree well with patterns obtained from simulations based on an invasion percolation model.

Experiments on and computer simulations of the migration of fractal, nonwetting fluid bubbles through a two-dimensional random porous medium saturated with wetting fluid are presented. A large invasion percolation bubble was initially formed by slow injection of a nonwetting fluid into a horizontal cell saturated with a denser wetting fluid. Slow, continuous tilting of the cell caused the bubbles to migrate through the medium. The interplay between local pinning forces and buoyancy led to fragmentation and coalescence of migrating bubbles. The process was simulated by a modified site-bond invasion percolation model.

The effects of gravity stabilization and destabilization on the slow displacement of a wetting fluid by a non-wetting fluid in two-dimensional and three-dimensional porous media have been investigated experimentally. The characteristic features of the resulting displacement patterns can be reproduced quite well by invasion percolation models with a spatial gradient added to the usual random threshold distribution. In the case of destabilized displacement the patterns can be described in terms of a string of blobs of size ξ that form a directed walk. The internal structure of the blobs is like that of an invasion percolation cluster (with trapping in the two-dimensional case). In the stabilized case the structure is like that of a fractal invasion percolation cluster on short length scales (lengths ⪡ξ) and is uniform on longer lengths. The correlation length (ξ) also describes the maximum hole diameter. The invasion front is a self-similar fractal on length scales shorter than ξ and flat on longer length scales. In both the experiments and the simulations the correlation length ξ is related to the Bond number (B0, the ratio between buoyancy and capillary forces) by ξ ∼ |B0|−ʋ(ʋ+1) where ʋ is the ordinary percolation correlation length exponent) in accord with the theoretical arguments of Wilkinson (Phys. Rev. A 30 (1984) 520; 34 (1986) 1380).

International Conference on Radioecology & Environmental Radioactivity