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Search Results: 1 - 10 of 1515 matches for " Josef Klusoň "
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Consistent Extension of Quasidilaton Massive Gravity
Josef Klusoň
Journal of Gravity , 2014, DOI: 10.1155/2014/413835
Abstract: This paper is devoted to the Hamiltonian analysis of extension of the quasidilaton massive gravity as was proposed recently in [arXiv:1306.5502]. We show that, for given formulation of the theory, the additional primary constraint that is responsible for the elimination of the Boulware-Deser ghost is missing. We compare this situation with the quasidilaton massive gravity. Finally, we propose the ghost-free extension of quasidilaton massive gravity. 1. Introduction and Summary Recently, new version of the full nonlinear massive gravity was found by de Rham, Gabadadze and Toley (dRGT) [1, 2] that provides the positive answer to the question of whether graviton can have a nonzero mass. In fact, among many remarkable properties, there is the crucial one which is the absence of the Boulware-Deser ghost [3, 4]. The consistent massive gravity could also provide a possible explanation of the observed acceleration of the cosmic expansion which is one of the greatest mysteries in modern cosmology. It is tempting to speculate that the finite graviton mass could be a source of the accelerated expansion of the universe. For that reason, it is of great interest to formulate theoretically consistent cosmological scenario in massive gravity that is also in agreement with the observations. Unfortunately, it was recently shown that all homogeneous and isotropic cosmological solutions in dRGT theory are unstable [5]; see also [6–8]. In order to resolve this problem, we have two possible options: either to break homogeneity [9] or isotropy [10, 11] or to extend the theory as in [12, 13]. Recently in [14], de Felice and Mukohyama proposed new extension of the quasidilaton massive gravity that could provide stable and self-accelerating homogeneous and isotropic cosmological solution. They further argued that given extension belongs to the class of models studied in [15] that are free from the Boulware-Deser ghosts. However, the explicit Hamiltonian analysis of given theory was not performed in [14]. The goal of this paper is to reconsider the problem of the Boulware-Deser ghost in the model [14]. We present an evidence that, for the action that was introduced in [14], the Boulware-Deser ghost cannot be eliminated. More precisely, performing the Hamiltonian analysis of this model with the time dependent quasidilaton, we find that the primary constraint which is responsible for the elimination of the ghost in Stückelberg formulation of nonlinear massive gravity [16–19] is missing (for related work, see [20]). This result implies that generally Boulware-Deser ghost is present.
New proposal for non-linear ghost-free massive $F(R)$ gravity: cosmic acceleration and Hamiltonian analysis
Josef Klusoň,Shin'ichi Nojiri,Sergei D. Odintsov
Physics , 2013, DOI: 10.1016/j.physletb.2013.10.003
Abstract: We propose new version of massive $F(R)$ gravity which is natural generalization of convenient massive ghost-free gravity. Its Hamiltonian formulation in scalar-tensor frame is developed. We show that such $F(R)$ theory is ghost-free. The cosmological evolution of such theory is investigated. Despite the strong Bianchi identity constraint the possibility of cosmic acceleration (especially, in the presence of cold dark matter) is established. Ghost-free massive $F(R,T)$ gravity is also proposed.
Higher derivative gravity with spontaneous symmetry breaking: Hamiltonian analysis of new covariant renormalizable gravity
Masud Chaichian,Josef Klusoň,Markku Oksanen,Anca Tureanu
Physics , 2012, DOI: 10.1103/PhysRevD.87.064032
Abstract: In order to explore some general features of modified theories of gravity which involve higher derivatives and spontaneous Lorentz and/or diffeomorphism symmetry breaking, we study the recently proposed new version of covariant renormalizable gravity (CRG). CRG attains power-counting renormalizability via higher derivatives and introduction of a constrained scalar field and spontaneous symmetry breaking. We obtain an Arnowitt-Deser-Misner representation of the CRG action in four-dimensional spacetime with respect to a foliation of spacetime adapted to the constrained scalar field. The resulting action is analyzed by using Hamiltonian formalism. We discover that CRG contains two extra degrees of freedom. One of them carries negative energy (a ghost) and it will destabilize the theory due to its interactions. This result is in contrast with the original paper [Phys. Lett. B 701, 117 (2011), arXiv:1104.4286 [hep-th]], where it was concluded that the theory is free of ghosts and renormalizable when we analyze fluctuations on the flat background.
Flying measuring scanning of mines, option of the optimum measure
Marcel Jano?,Zdeněk Klusoň
Acta Montanistica Slovaca , 2007,
Abstract: The paper is focused on a topic, which deals with spatial data acqusition from the aerial images. The aerial photography is used for updating mine maps, digital terrain model, GIS input data, cubic measurements for many years. The repeated aerial scannings in predeterminetd periods for monitoring of open cut mines is carried. The choice of right scale is influenced by many parameters. The accuracy of height and position outputs the most important of them. Other parameters such as size and character of the location, weather conditions, type of film, laboratory treatment and postprocessing also need to be taken into a consideration. The reasons for choosing scale 1:5000 instead of 1:7 000 for two big open mine companies and our experiences will be presented in our paper.
Ombudsmen in Higher Education: Helping the Single Student, Contributing to the Universities’ Institutional Changes  [PDF]
Josef Leidenfrost
Creative Education (CE) , 2013, DOI: 10.4236/ce.2013.47A2002
Abstract:

This article aims to firstly give a brief insight into the major challenges for modern time universities like necessary change management, growing competitiveness, increasing expectations by the stakeholders and how rising tuition fees affect all of that, and secondly on the growing pressure for universities on responding more effectively to a demanding student population, mounting expectations and diverse backgrounds of students, and thirdly how alternative dispute resolution is more and more commonly used as a means of resolving disputes and complaints informally and at an early stage in order to avoid litigation and the courts. It is described how ombudsmen in higher education can help to minimize the students’ feelings of disconnection created by formal and judicial processes and get fair treatment. Catering either for students only or for the whole university community, ombudsmen provide confidential, impartial complaints handling services and also contribute to change management on the macro level and hence help with changing policies.

Peri-Ocular Eye Patterning (POEP): More than Meets the Eye  [PDF]
Noam Josef
Open Journal of Animal Sciences (OJAS) , 2017, DOI: 10.4236/ojas.2017.73027
Abstract: Spatial body patterning is widely observed throughout the phylogenetic tree and is used for a variety of functions. Body colours in general and camouflaging patterns in particular have been extensively studied for their role in stealth and crypsis. Particular interest has focused on the diverse skin patterns surrounding animals’ eyes (Peri-Ocular Eye Patterning-POEP). These patterns have been suggested to aid in high brightness conditions, help camouflage an organism’s eyes or ornament and emphasize bright head colorations. In this work I demonstrate the apparent widespread use of POEP among various marine and terrestrial organisms (both vertebrates and invertebrates) and discuss the trait’s abundance, variations, and possible roles.
Tobacco, alcohol and illegal substances: experiences and attitudes among Italian university students
Kra?marová, Lenka;Klusoňová, Hana;Petrelli, Fabio;Grappasonni, Iolanda;
Revista da Associa??o Médica Brasileira , 2011, DOI: 10.1590/S0104-42302011000500009
Abstract: objective: the purpose of this research was to assess the prevalence of addictive drug use among students of university of camerino (italy) and to verify aspects related to substance use in this population. methods: the survey was carried out in the form of anonymous questionnaires completed by 345 participants. chi-square test was used for statistic evaluation. results: most students have experienced legal addictive substances: 28.0 % of participants smoke cigarettes regularly and 23.2 % of respondents have admitted regular alcohol consumption. in addition, 50.4 % of subjects have already tried an illegal drug; the most used substance was cannabis (46.7 %), followed by cocaine (13.3 %). conclusion: our results confirmed the increased experimental use of cannabis among young people in europe and showed a long-term use of drugs, particularly cocaine, among university students.
Impact of Noise Barriers on Air-Pollution Dispersion  [PDF]
Josef Brechler, Vladimir Fuka
Natural Science (NS) , 2014, DOI: 10.4236/ns.2014.66038
Abstract:

The impact of noise barriers on gaseous air-pollution dispersion was examined using the high-resolution CLMM (Charles University LES (Large Eddy Simulation) Microscale Model). The dispersion of a mixture of nitrogen oxides (denoted as NOx—a mix of NO and NO2) was computed, providing the simulation in which wind direction is approximately perpendicular to the noise barriers. The barriers were assumed to be straight and infinitely long, with a height of 3 m. Dispersion of NOx was modeled for situations with no noise barriers along the highway, barriers on both sides, and for a single barrier on the upwind and downwind sides of the highway. The modelling results are presented and discussed in relation to previous studies and the implications of the results are considered for pollution barriers along highways.

Analysis of Urban Change in Shenzhen City Based on Landsat Archived Data  [PDF]
Tingting Chen, Hermann Josef Kaufmann
Journal of Computer and Communications (JCC) , 2018, DOI: 10.4236/jcc.2018.611014
Abstract:
With the ongoing development of economy and urbanization in China, the change of land use types has attracted more and more attention. In this study we focused on the urban development of Shenzhen City, Guangdong Province, analyzing Landsat 5 TM and Landsat 8 OLI data. We used an SVM based classification, a land transfer matrix approach, a directional growth analysis method and we calculated the inversion of land surface temperature to derive information of land cover changes that occurred in the time period between 1987 and 2017. The results are combined with Shenzhen’s economy, transportation policy and other aspects to find the driving forces of the urban development. The results show that during the observed 30 years, the area of construction land has increased significantly. Most of it is converted from other lands, and some of them are reclaimed. Most rapidly developing are areas west and northwest of the Bao’an, Nanshan and Longhua. The vegetated areas decreased slightly. Caused by the continuous increase of the construction land, the so-called heat island effect emerges slightly but continuously.
Bounded solutions of nonlinear Cauchy problems
Josef Kreulich
Abstract and Applied Analysis , 2002, DOI: 10.1155/s1085337502208015
Abstract: For a given closed and translation invariant subspace Yof the bounded and uniformly continuous functions, we will give criteria for the existence of solutions u∈Yto the equation u′(t)
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