1,112 research outputs found

    Gauge theories induced by bosons in fundamental representation

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    A lattice theory of scalar bosons in the fundamental representation of the gauge group SU(Nc)SU(N_c) and of the global symmetry group SU(Nf)SU(N_f) is shown to induce a standard gauge theory only at large NfN_f. The system is in a deconfined phase at strong scalar self-coupling and any finite NfN_f. The requirement of convergence of the effective gauge action imposes a lower limit on the scalar mass.Comment: 11 page

    Effects of some ecological factors on Dothichiza populea Sacc. et Br. growth

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    The aim of the present work was to evaluate the mycelial growth and fruiting vigor of Dothichiza populea Sacc. et Br. under various temperatures, pH values, and light regimes. Effect of temperature on the fungus growth was examined by growing isolates in polythermostat at 5°C to 30°C. The best mycelial growth occurred at 20°C, while at 30°C it was inhibited. Fruiting of the fungus was not observed at 5°C, 25°C, and 30°C. However, the best fruiting of the isolates appeared at 20°C. The influence of different pH of the cultivation medium (3,5-10) on the fungus isolates growth was also evaluated. Optimal pH for the fungus growth ranged between 6 and 8, while formation of reproductive organs occurred at all pH values. The influence of two light regimes (light/dark regime and continuous dark) on the fungus growth was also studied. Obtained results showed that mycelial growth and fruiting of the fungus were considerably better under the light/dark regime

    Effect of Resonance in Soil-Structure Interaction for Finite Soil Layers

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    In case of seismic design the deformability of the soil should be considered, which can be performed in several ways. Most of the methods do not take into account the finite dimensions of the soil, which results significantly different behavior than the spring-dashpot systems. For an infinite medium, which is used in many cases, there are no eigenmodes, however in practical applications the soft soil is always bounded by rocks. For these cases the soil has eigenmodes and the resonance may influence considerably the response of the system. This question was investigated numerically by FE calculations, and it was found that in certain cases the resonance, which is neglected in the common design process, may significantly enhance the earthquake loads. In this paper this phenomenon is investigated and the parameter range is defined when this effect must be taken into account

    Model of Soil-structure Interaction of Objects Resting on Finite Depth Soil Layers for Seismic Design

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    In case of seismic design of structures the deformability and damping of the soil should be considered, which can be performed in several ways. The infinite soil half space can be approximated with the cone model, which gives constant values for the spring stiffnesses and dashpot characteristics, and an additional mass element for rocking motion. To approximate the dynamic impedance function of a soil layer more complex models were also applied. Most of the methods do not take into account the finite dimensions of the soil, which results significantly different behavior than spring-dashpot systems. To consider the effect of a finite layer a new simple model based on a physical approach is given for the horizontal excitation of strip foundations. Numerical verification is presented, and the parameter range is determined, where the application of the new model is recommended, since applying a spring-dashpot model results in significant errors

    Effect of temperature, relative humidity and light on conidial germination of oak powdery mildew (Microsphaera alphitoides Griff. et Maubl.) under controlled conditions

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    The influence of temperature, humidity and light on the conidial germination and germ tube elongation of oak powdery mildew (Microsphaera alphitoides Griff. et Maubl.) was studied in controlled conditions. The maximal germ tube length was attained at 25°C, whereas at lower and higher than optimal temperatures, germ tube growth was significantly lower. Germ tubes begin to develop at all values of relative humidity (10-100%), reaching the maximum length at 90%. The development of germ tubes was the most intense in full light and the lowest in total darkness. The artificial infection of floating leaves showed that an increasing age had an inhibitory effect on the mycelium development and spore formation. Since conidia play a crucial role in powdery mildew epidemiology, it is of particular importance to elucidate the influence of environmental factors in the complex relations that exist between the plant and its pathogen

    Pervasive decline of subtropical aquatic insects over 20 years driven by water transparency, non-native fish and stoichiometric imbalance.

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    Insect abundance and diversity are declining worldwide. Although recent research found freshwater insect populations to be increasing in some regions, there is a critical lack of data from tropical and subtropical regions. Here, we examine a 20-year monitoring dataset of freshwater insects from a subtropical floodplain comprising a diverse suite of rivers, shallow lakes, channels and backwaters. We found a pervasive decline in abundance of all major insect orders (Odonata, Ephemeroptera, Trichoptera, Megaloptera, Coleoptera, Hemiptera and Diptera) and families, regardless of their functional role or body size. Similarly, Chironomidae species richness decreased over the same time period. The main drivers of this pervasive insect decline were increased concurrent invasions of non-native insectivorous fish, water transparency and changes to water stoichiometry (i.e. N : P ratios) over time. All these drivers represent human impacts caused by reservoir construction. This work sheds light on the importance of long-term studies for a deeper understanding of human-induced impacts on aquatic insects. We highlight that extended anthropogenic impact monitoring and mitigation actions are pivotal in maintaining freshwater ecosystem integrity

    Human Resource Development as a possibility for developing the most underdeveloped micro-regions of Hungary

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    One of the problems in regional development policy having been present for a long time – and presumably to remain for a long while – is developing the most underdeveloped regions. Unfortunately the difference between the developed and the underdeveloped has increased in Hungary during the last two decades – despite the strengthening regional politics. These regions are usually afflicted with multiple disadvantages, therefore it is not enough to explore and change only one cause leading to underdevelopment. It is of complex origin; the effect of several correlated factor-layers can be observed. It is an elemental thesis in case of local improvements that investing into human resources (to put it in an ordinary way, into people) and improving the conditions of the population (qualification, healthcare, standards of living, etc.) is one of the most efficient and less costly means to eliminate underdevelopment. Despite its cost-efficiency only long-term results can be expected; in many cases it takes generations to benefit from the investment. In this work we will review the conclusions and suggestions of the educational aspects of a complex Hungarian development programme
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