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Given the uncertainty of the navigating conditions on the Danube River, the hydrological situation on the Bulgarian leg of the river is predicted using ARIMA methods. The forecast is based on statistical daily hydrological data for a period of five years. A mathematical routing model is developed under the condition that it is not possible for a self-propelled vessel to continue its voyage due to draft limitation. Options including waiting for navigation opening, partial lightening on a barge, and a complete or partial modal shift to rail or road transport through an alternative port are considered. An acceptable option is determined, taking into account the additional costs and transit time. A routing simulation is made using SPSS software. [ABSTRACT FROM AUTHOR]

The article concerns subrecursive computability of real numbers. Certain significant real numbers are shown to be M2-computable, and the set of the M2-computable real numbers is shown to be closed under the elementary functions of calculus. [ABSTRACT FROM AUTHOR]

Abstract: Molecular mechanisms, responsible for the impaired insulin-sensitivity state due to the obesity are not fully understood in both humans and animals. The purpose of this study was to investigate the effects of castration-induced visceral obesity and the influence of two antioxidants on constituents of blood lipid profile and insulin sensitivity in New Zealand white rabbits. Twenty-six clinically healthy male New Zealand white rabbits were used in the experiment and were divided into 3 groups: first group (CI, n =7) – castrated-obese and treated with antioxidants “Immunoprotect” for 2months; second group (CO, n =7) – castrated-obese; third group (NC, n =12) – control group (non-castrated, non-obese). At the end of the follow-up period of 2months after castration an intravenous glucose tolerance test (IVGTT) was performed after a 12-h fasting period as the blood samples for determination of glucose and insulin and their kinetic parameters were obtained at 5 and 0min before and at 5, 10, 30, 60 and 120min after the infusion of the glucose. The constituents of lipid profile, triglycerides (TG), total cholesterol (TC) and HDL-cholesterol (HDL-C) were also assessed in the overnight fasting blood samples. The body weight (BW), body mass index (BMI), amount of the visceral fat (VF) and VF/BW ratio were both measured and calculated before the IVGTT and at the end of the experimental period. All measured markers of obesity (BW, BMI, VF, VF/BW) were significantly higher in both groups of castrated rabbits than in the control group. Apart HDL-C, the plasma concentrations of all constituents of lipid profile (TG, TC, HDL-C) were the highest in CO group. There were generally no differences between CI and NC groups for the same traits. After glucose injection blood glucose concentrations and glucose and insulin kinetic parameters were considerably higher (except of glucose elimination rate) in CO rabbits than in NC ones. Castrated rabbits treated with “Immunoprotect” showed lower fasting plasma insulin and improved glucose kinetics dynamics than CO rabbits, but commensurable values of glucose and insulin kinetics parameters than NC group. The results of the current study clearly indicated that castration-induced visceral obesity affected negatively the lipid profile and insulin sensitivity and/or responsiveness. Treatment with antioxidant supplementation, consisted of d-limonene and vitamin E, improved blood lipid profile, fatty liver, glucose homeostasis and insulin sensitivity in obese rabbits. In addition, based on our results we may suggest that castrated male New Zealand white rabbits might be considered as an appropriate animal model to study various metabolic abnormalities related to visceral obesity, such as dyslipidemia and impaired insulin sensitivity. [Copyright &y& Elsevier]

Triangulation data from first order geodetic network of Bulgaria measured between 1923 and 1929 and GPS data from last two decades have been processed together. The results for horizontal velocities is about 1-3 mm/y. The strain rate in Central Western Bulgaria region is estimated. Principal axes of the horizontal strain rate are calculated from the constrained velocity solution. The results are used to constrain the active faults in the region. The joint GPS and triangulation data analysis can contribute to estimation the crustal strain even in areas with low rate of deformation and to constrain the recent tectonics. [ABSTRACT FROM AUTHOR]

As obesity is a state of low-grade inflammation, we aimed to investigate the combined effect of high-fat diet and bacterial infection on β-cell function and insulin sensitivity in dogs. We used 20 healthy, male, mongrel dogs randomly divided into four groups: control group—healthy, non-obese dogs; infected group—non-obese dogs with experimentally induced infection ( Staphylococcus intermedius); obese group—obese dogs (after 90 day high-fat diet) and obese-infected group—obese dogs with experimentally induced infection ( Staphylococcus intermedius). To evaluate insulin sensitivity and β-cell function an intravenous glucose tolerance test (IVGTT) was performed. Plasma insulin increased in all group after glucose infusion. The lowest values were found in obese-infected group. Blood glucose also increased on 3 min after glucose infusion and then gradually decreased. In obese-infected group glucose concentration on 30 min was still significantly higher than initial levels, while in other groups glucose concentration returned to the initial values. The lowest rate of glucose elimination was found in infected group. In dogs of obese group and obese-infected group AUCins 0–60 min was lower compared to controls. AUCglucose 0–60 min values were lowest in infected group, while in obese-infectd group values were the highest. Levels of ∆I/∆G in dogs of obese-infected group were significantly lower compared to controls and infected group. In conclusion, these results reveal that infection in obese dogs leads to impaired glucose tolerance, which is result of impairment in both insulin secretion and insulin sensitivity. [ABSTRACT FROM AUTHOR]

This paper estimates the effect of diversification on farm effectiveness through modelling using data from the National Statistical Institute of Bulgaria. The estimation of the role of diversification in agriculture is similar to this in corporate firms. The results show that the number of diversification activities has a significant effect on the final economic results. The introduction of the factor of lifetime of the firms with its effect on size of revenues from diversification activities is a new feature in this study. The above mentioned provides an opportunity for adaptation and effective operation of the business in the variable market environment, as well as a useful referent for public responsibles in order to design adequate supporting programmes. On the other hand, this paper refines Berger and Ofek’s methodology by adapting it to the conditions of the agricultural production in Bulgaria. Main differences are related to the selection of the considered factors and the final economic result. The latter is extra revenue from diversification activities and the selected representative sample of firms is grouped by the criteria of number of diversification activities. [ABSTRACT FROM AUTHOR]

We study the general properties of stochastic two-species models for predator-prey competition and coexistence with Lotka–Volterra type interactions defined on a d-dimensional lattice. Introducing spatial degrees of freedom and allowing for stochastic fluctuations generically invalidates the classical, deterministic mean-field picture. Already within mean-field theory, however, spatial constraints, modeling locally limited resources, lead to the emergence of a continuous active-to-absorbing state phase transition. Field-theoretic arguments, supported by Monte Carlo simulation results, indicate that this transition, which represents an extinction threshold for the predator population, is governed by the directed percolation universality class. In the active state, where predators and prey coexist, the classical center singularities with associated population cycles are replaced by either nodes or foci. In the vicinity of the stable nodes, the system is characterized by essentially stationary localized clusters of predators in a sea of prey. Near the stable foci, however, the stochastic lattice Lotka–Volterra system displays complex, correlated spatio-temporal patterns of competing activity fronts. Correspondingly, the population densities in our numerical simulations turn out to oscillate irregularly in time, with amplitudes that tend to zero in the thermodynamic limit. Yet in finite systems these oscillatory fluctuations are quite persistent, and their features are determined by the intrinsic interaction rates rather than the initial conditions. We emphasize the robustness of this scenario with respect to various model perturbations. [ABSTRACT FROM AUTHOR]

The cytokine macrophage migration inhibitory factor (MIF) plays a critical role in inflammatory diseases and atherogenesis. We identify the chemokine receptors CXCR2 and CXCR4 as functional receptors for MIF. MIF triggered Gαi- and integrin-dependent arrest and chemotaxis of monocytes and T cells, rapid integrin activation and calcium influx through CXCR2 or CXCR4. MIF competed with cognate ligands for CXCR4 and CXCR2 binding, and directly bound to CXCR2. CXCR2 and CD74 formed a receptor complex, and monocyte arrest elicited by MIF in inflamed or atherosclerotic arteries involved both CXCR2 and CD74. In vivo, Mif deficiency impaired monocyte adhesion to the arterial wall in atherosclerosis-prone mice, and MIF-induced leukocyte recruitment required Il8rb (which encodes Cxcr2). Blockade of Mif but not of canonical ligands of Cxcr2 or Cxcr4 in mice with advanced atherosclerosis led to plaque regression and reduced monocyte and T-cell content in plaques. By activating both CXCR2 and CXCR4, MIF displays chemokine-like functions and acts as a major regulator of inflammatory cell recruitment and atherogenesis. Targeting MIF in individuals with manifest atherosclerosis can potentially be used to treat this condition. [ABSTRACT FROM AUTHOR]

Rural tourism related activities have been widely regarded as key-tools for rural development, specially in those countries —as Romania and all East European countrieswhere rural space and production is still a major part of whole economic structure, trying by this way to revitalize declining areas and ensure them possibilities of achieving a sustainable future. At this purpose, rural tourism must be considered like a complex plurality of multi-faced activities, contributing both to growth of other activities in rural areas and to improvement of life quality for local inhabitants, all this as part of an effective rural development integrated system. Due to necessary attraction of foreign currency in order to contribute in solving structural troubles of national economies in these countries, design of quite a lot of rural tourism activities on there has usually focused on international demand. However, and even when this could be perfectly right at a first stage, evidence for other countries shows that long-time maintenance of such activities requires of the existence of a —perhaps not so attractive, but indispensable— internal market. In this paper, we give first descriptive evidence about existence and characteristics of this domestic —and mostly unexpected— market for rural tourism activities in Romania. [ABSTRACT FROM AUTHOR]

The materials used for the synthesis of parent glass are 70% wt. metallurgical slag and 30% wt. industrial quartz sand. The initial batch is melted at and then quenched in water. The resulting glass frit is milled bellow 75 microns and pressed 1400 °C into "green" samples. In a next stage, they are heat treated at different temperatures with various heating rates and holding times. As a result, it is demonstrated the possibility for production variations, allowing the manufacture of three types of new materials by using the same pressed glass powders. We highlight the flexibility of the synthesis obtaining namely well densified glass-ceramics at about 950 °C, self-glazed glass-ceramics at about 1000 °C or glass-ceramic foams at approximately 1100 °C. The first set of materials is characterized by very well sintered structure combined with reasonable crystallinity; the second one—by smooth self-glazed surface with an attractive appearance and good properties and the third one—by 80–90% closed porosity and very good thermal stability above 1000 °C. [ABSTRACT FROM AUTHOR]

Cauchy sequences, Dedekind cuts, base-10 expansions and continued fractions are examples of well-known representations of irrational numbers. But there exist others, not so popular, which can be defined using various kinds of sum approximations and best approximations. In this paper we investigate the complexity of a number of such representations. For any fast-growing computable function f , we define an irrational number α f by using a series of reciprocals of powers of all primes. We prove that certain representations of α f are of low computational complexity (which does not depend on f), whereas others, apparently similar representations, can be of arbitrarily high computational complexity (which depends on f). The existence of computable numbers like α f allows us to prove new and non-trivial theorems on the computational complexity of representations without resorting to the standard computability-theoretic machinery involving enumerations and diagonalizations. In the paper we also show how to construct irrational numbers γ whose representations by a Cauchy sequences are of low computational complexity, but whose base- b expansion may be of arbitrarily high computational complexity for all bases b. Moreover, for any E 2 -irrational number α , there will be an E 2 -irrational number β , such that α + β has the complexity of γ. As a consequence, two numbers which have, let us say, base-10 expansions of low computational complexity, may add up to a number whose base-10 expansion is of arbitrarily high computational complexity. The same goes for representations by base-2 expansions, base-17 expansions, Dedekind cuts, continued fractions, and so on. [ABSTRACT FROM AUTHOR]

We consider the complexity of the integration operator on real functions with respect to the subrecursive class M 2. We prove that the definite integral of a uniformly M 2 -computable analytic real function with M 2 -computable limits is itself M 2 -computable real number. We generalise this result to integrals with parameters and with varying limits. As an application, we show that the Euler-Mascheroni constant is M 2 -computable. [ABSTRACT FROM AUTHOR]

When delivering goods in the warehouses of enterprises, courier and forwarding companies, and for logistics operators, loading and unloading is usually done manually or mechanically. On the other hand, the load can first be placed on the ground next to the vehicle and then accepted in the pile, or a ramp can be used so that it can be delivered directly to the warehouse or vice versa. When there is a ramp, the loading and discharging activity is performed faster and it is much easier. When there are many vehicles serviced on ramps, it is necessary to have a free ramp available. This is often not the case when the warehouse has more ramps and a large exchange of goods. In this case, a time schedule is usually made for the reception and handling of vehicles, which is communicated to carriers and drivers so that there is no unnecessary downtime of vehicles and overloading of points with ramps. There are cases in which the established organization of work cannot be performed due to various force majeure or other reasons, such as delays at border crossings, bans on passing through certain sections, change in the working hours of warehouses, pandemic and other reasons. The vehicles then arrive at the checkpoints at a time that is different from their schedule and have to wait to be serviced. Waiting at the unloading points makes drivers nervous and they become dissatisfied with the working conditions. In this respect, a solution has been proposed based on the working hours and occupancy of the loading and discharging point and the time of arrival of the vehicles at the point, and how to receive the vehicles so that the waiting time between them is the shortest. For this purpose, a partially integer linear optimization model has been created in Matlab, which provides a valid plan with the shortest waiting times for all vehicles. Simulations have been made for different numbers of ramps and vehicles. The results show that the model is suitable for pre-creating a valid plan for the operation of the vehicle warehouse, if any, with a minimum waiting time. [ABSTRACT FROM AUTHOR]