435 research outputs found

    Physics Reach of High-Energy and High-Statistics IceCube Atmospheric Neutrino Data

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    This paper investigates the physics reach of the IceCube neutrino detector when it will have collected a data set of order one million atmospheric neutrinos with energies in the 0.1 \sim 10^4 TeV range. The paper consists of three parts. We first demonstrate how to simulate the detector performance using relatively simple analytic methods. Because of the high energies of the neutrinos, their oscillations, propagation in the Earth and regeneration due to \tau decay must be treated in a coherent way. We set up the formalism to do this and discuss the implications. In a final section we apply the methods developed to evaluate the potential of IceCube to study new physics beyond neutrino oscillations. Not surprisingly, because of the increased energy and statistics over present experiments, existing bounds on violations of the equivalence principle and of Lorentz invariance can be improved by over two orders of magnitude. The methods developed can be readily applied to other non-conventional physics associated with neutrinos.Comment: 21 pages, 7 figures, Revtex

    Pedagogical determinants of drug prevention in the Russian secondary school

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    The spread of drug addiction in the school environment is a serious danger to society. The work aiming at prevention students' drug addiction causes a search for complex methods in preventive antidrug activities in the educational process. A pedagogical approach to the problem of drug addiction brings out the school teaching staff potential to resist the process of secondary school students' drug abuse. This article provides such a pedagogical approach and investigates a secondary school potential to be used in opposition to the expansion of drug addiction among secondary school students. We define measures to prevent students' drug abuse as a specially organized process aimed at eliminating or weakening to the least possible degree the factors inducing students to try and abuse drugs. Our study examines various directions of anti-drug measures, which can compensate for the negative features of schoolchildren's life. © 2014 Taylor & Francis Group

    Age estimation of black locust (Robinia pseudoacacia) based on morphometric traits

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    The use of black locust (Robinia pseudoacacia L.) is still controversial, especially in managed forests, due to its invasive nature. The black locust has been proven effective in reclamation of degraded lands when native species are not an alternative in the face of the climate change and desertification. Therefore, the importance of black locust in European ecosystems remains a matter of debate. Of course, it is an adventitious species originating from another continent. However, the ecological characteristics of the species in its natural range are very useful for ensuring the restoration of vegetation cover in areas that have experienced significant anthropogenic pressure. This species has a large number of important and useful features that make it an important agent in the forestry system and provide significant environmental and economic benefits. The status of black locust as an invasive species, i.e. one that is capable of uncontrolled spread, remains speculative. Such a conclusion requires various studies, including those identifying exact age of the plants based on morphometric parameters. In our study, we tested the hypothesis that plant height and trunk diameter will allow for an accurate assessment of black locust age. The plants of black locust were measured in the zone of spontaneous self-seeding of plants from a planted 60-years-old forest. The plants dispersed towards a fallow land, formed in the corner of an agricultural field. The spreading began 15 to 20 years ago. The plants are mainly propagated by seedlings. An expert estimated the age of the plants visually. The measured trees were cut to obtain cross sections to account for the number of annual rings. A total of 68 trees were examined for morphometric characters. Black locust communities during self-dispersal are represented by individuals of different ages. The spatial pattern of distribution of individuals of different ages can reveal the spatial and temporal dynamics of the formation of spontaneous populations of black locust. For this purpose, it is critical to accurately identify the age of a large sample. Expert estimation of age is fast and fairly accurate, but it depends greatly on the qualifications of the expert and oftentimes plant ages are underestimated, especially in the early stages of population development. Plant height is also a good predictor of plant age, but the model gives poor predictions for plants older than 10 years. The tree height ranged 2.3 to 16.0 meters. The diameter at breast height (DBH) ranged 1.0 to 17.5 cm. The diameter at the root collar (DRC) ranged 1.6 to 21.7 cm. The age of the studied trees, determined by the number of annual rings per transect, ranged 6 to 17 years. The age of the trees according to the expert estimates was 8.2 ± 4.8 years. The expert estimates of age and the age according to the number of annual rings were statistically significantly different. The expert estimates of tree age were linearly related to tree size, while estimates of the number of annual rings showed a logarithmic relationship with tree height. Expert estimates also showed a closer relationship with tree height, while the relationship of estimates based on the number of annual rings had a slightly lower dependence on the morphometric traits. Regression analysis showed that there is a linear relationship between morphometric traits of the black locust. The coefficient of determination for the dependence of diameter at breast height on tree height was 0.96, and for the dependence of diameter at the base of the trunk on diameter at breast height was 0.97. This indicates a high level of multicollinearity of these morphometric traits when considering them as predictors of plant age. Taking into account the diameter at breast height and the diameter at the level of the root collar significantly improved the predictive ability of the model for identifying the age of the black locust trees

    Prospects for identifying the sources of the Galactic cosmic rays with IceCube

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    We quantitatively address whether IceCube, a kilometer-scale neutrino detector under construction at the South Pole, can observe neutrinos pointing back at the accelerators of the Galactic cosmic rays. The photon flux from candidate sources identified by the Milagro detector in a survey of the TeV sky is consistent with the flux expected from a typical cosmic-ray generating supernova remnant interacting with the interstellar medium. We show here that IceCube can provide incontrovertible evidence of cosmic-ray acceleration in these sources by detecting neutrinos. We find that the signal is optimally identified by specializing to events with energies above 30 TeV where the atmospheric neutrino background is low. We conclude that evidence for a correlation between the Milagro and IceCube sky maps should be conclusive after several years.Comment: 5 pages, 5 figures; part of the text and some figures have changed, conclusions remain the same; equals journal versio

    Urban park layers: Spatial variation in plant community structure

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    Horizontal structure of natural plant communities attracted the attention of researchers for a long time, while the problem of horizontal structure of urban park plantations was not studied sufficiently. Species richness of different tiers of park plantation in the large industrial city of Dnipro (Ukraine) was revealed in this study. Also features of variation in the structure of plant communities at different spatial levels were revealed, the influence of park plantation canopy on the understory and herbaceous layer of the park. There were 30 plant species in the tree layer of the park plantation. The most common species were Robinia pseudoacacia L., Acer platanoides L., A. negundo L., Gleditsia triacanthos L., Aesculus hippocastanum L., Populus carolinensis Moench. The variance-to-mean ratio revealed that 13 tree species were randomly distributed throughout the park, and 14 species were aggregated. The number of occurrences of a given tree species per site and variance-to-mean ratio were positively correlated. The numerous tree species showed a tendency of aggregated distribution within the park. Sixteen plant species were found in the understory. Among them, the most abundant species were Acer platanoides L., A. negundo L., A. pseudoplatanus L., Sambucus nigra L., Robinia pseudoacacia L. Eight species were found to be randomly distributed over the park area, and eight species showed an aggregate distribution. The number of species encountered in the understory and variance-to-mean ratio were positively correlated. In the herbaceous stand, 99 plant species were found, of which Chelidonium majus L., Viola odorata L., Impatiens parviflora DC., Parthenocissus quinquefolia (L.) Planch., Geum urbanum L. predominated. The variance-to-mean ratio of all species was significantly less than unity, indicating regular spatial distribution. The values of alpha- and gamma-diversity of the plant community in separate layers are very different. The highest gamma diversity was found for the herbaceous stand, while the diversity of the tree stand and understory was significantly lower. Alpha biodiversity of the tree stand and the understory did not practically differ. Beta diversity values between the layers are very close, and beta diversity is practically equal for tree stand and herbaceous layer. Thus, we can assume that the mechanisms of species turnover for the plant communities of different layers are determined by the common causes. The spatial broad-scale component was able to explain 8.2% of community variation, the medium-scale component was able to explain 4.2% of community variation, and the fine-scale component was able to explain 0.7% of community variation. The understory is the most sensitive to the environmental factors, the herbaceous stand is somewhat less sensitive, and the tree stand is the least sensitive to the environmental factors. The environmental factors in this study are represented by a set of variables. The spatial variation of the stand is predominantly influenced by the factors of trophicity and moisture of the edaphotope. These same factors also act on the herbaceous stand and understory, but along with them are included the environmental variables, which are determined by the architectonics of the crown space and thus the light regime, which is regulated by the tree stand. It is important to note that the variation of the communities of the different layers of the park plantation is subject to spatial patterns. The herbaceous and understory variation is more spatially structured than the tree stand variation. The spatial patterns can arise as a result of the influence of spatially structured environmental factors and as a result of factors of a neutral nature. The latter aspect of variation is best described by the pure spatial component of community variation

    Preclinical manifestations of students’ eating disorders as an impact of the information and communication university environment

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    Students’ eating disorders include conditions and diseases characterized by irregular foods intake accomplished by stable anxiety effect regarding the mass and shape of their bodies. Information and communicative university environment is able to create a motivation for eating disorders, which damages individual’s health and well-being. The most typical forms of students’ eating disorders affected both girls and boys, are nervous bulimia and anorexia nervos

    Confounding factors in sport activities of powerlifters

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    Sporting activities are characterized by high physical and psycho-emotional stress. Modern trends in powerlifting are aimed at improving the technical and psychological training, improving physical form improving competition rules. The results of our research work describe the factors that cause of disorganization of powerlifters. 160 athletes going in for in powerlifting take part in the questionnaire to solve the problem. The sample included 80 women and 80 men, aged 16 to 49 years. Results of the study will determine the search for optimal solutions of the confounding factors in powerlifting athletes that in the future will make it possible to increase a sports result of the athletic

    Powerlifters' ways to overcome confounding factors at competitions

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    Competitive activity is accompanied by a number of factors that prevent athletes' high performance. Like all other athletes, powerlifters find solutions to fight interference emerging at the competitions. The study aims to explore possible ways to overcome the confounding factors in powerlifting. Respondents to the questionnaire were 160 lifters (80 men and 80 women) aged from 16 to 49, with sport experience from 1 year to 34 years and sports qualifications from third junior rank to the Master of Sports, some having the title of "Master of Sports of Russia of International Class". The study builds a hierarchy of ways to overcome the confounding factors according to the degree of their significance. The first five options were analyzed being most important in the athletes' viewpoint

    Ways to overcome confounding factors in powerlifters' training workouts

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    Training activities in powerlifting involve a variety of circumstances that constrain their optimal procedure. Exploring ways to overcome the confounding factors reveals possible ways to solve the problem. The study comprises observation and interviewing 80 men and 80 women involved in powerlifting. The analysis of the questionnaires shows that the top position is occupied by the method "coach's assistance". Following it in the hierarchy arranged according to the order of significance for athletes-powerlifters are: 2nd - mental attitude, 3d - selection of partners for training, 4th - instructional techniques, 5th - changing the training methods, 6th - medication, 7th - social isolation, 8th - selective communication, 9th - home-like behavior. The study is a discussion of the top five ways to overcome the confounding factors in the conditions of training activities that are most important from the standpoint of powerlifters

    High-pressure behavior of superconducting boron-doped diamond

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    This work investigates the high-pressure structure of freestanding superconducting (TcT_{c} = 4.3\,K) boron doped diamond (BDD) and how it affects the electronic and vibrational properties using Raman spectroscopy and x-ray diffraction in the 0-30\,GPa range. High-pressure Raman scattering experiments revealed an abrupt change in the linear pressure coefficients and the grain boundary components undergo an irreversible phase change at 14\,GPa. We show that the blue shift in the pressure-dependent vibrational modes correlates with the negative pressure coefficient of TcT_{c} in BDD. The analysis of x-ray diffraction data determines the equation of state of the BDD film, revealing a high bulk modulus of B0B_{0}=510±\pm28\,GPa. The comparative analysis of high-pressure data clarified that the sp2^{2} carbons in the grain boundaries transform into hexagonal diamond.Comment: 7 pages, 4 figure
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