3,862 research outputs found
Positive Entropy Through Pointwise Dynamics
We define some pointwise properties of topological dynamical systems and give
pointwise conditions for such a system possesses positive topological entropy.
We give sufficient conditions to obtain positive topological entropy for maps
which are approximated by maps with the shadowing property in a uniform way.Comment: 8 page
AGRICULTURAL PLANNING EXPERT: A MODEL OF FARM ENTERPRISE SELECTION
Agricultural Planning Expert is a software model designed for advising small-scale farmers in southern Maryland. Choosing farm enterprises is modelled as consisting of four activities: suggesting enterprises for consideration, investigating the suitability of enterprises, allocating resources to suitable enterprises, and controlling the overall direction of an advising session.Farm Management,
Searching for emission-line galaxies: The UCM survey
We are carrying out a long-term project with the main purposes of finding and analyzing low metallicity galaxies. A very small number of very low metallicity galaxies is known up to now. However these ojbects are particularly interesting since they are excellent candidates to 'young galaxies' in evolutionary sense as POX186 (Kunth, Maurogordato & Vigroux, 1988). Since the interstellar matter in these objects is only weakly contaminated by stellar evolution, their study could provide valuable information about the primordial helium abundance and therefore it could place constraints on the different Big-Bang models. The instrumental set up of our survey is an objective-prism used with the Schmidt telescope at Calar Alto Observatory. By using hypersensitized IIIaF emulsion and RG630 filter low resolution spectra in the H alpha region of objects in a wide field is obtained (Rego et al. 1989, Zamorano et al. 1990). Surveys carried out in the past two decades at optical blue wavelengths have also produced large samples of emission-line galaxies (ELGs), for example MacAlpine & Willians 1981 and reference therein, Wasilewski 1983, Salzer and MacAlpine 1988, or Smith et al. 1976. Relying primarily on objective-prism plates taken in the blue, these surveys have found over 3000 blue/emission-line galaxies so far. A significant number of star-forming galaxies are missed by optical surveys in the blue because of their low-excitation spectra (MacAlpine and Willians 1981, Markarian et al. 1981 and references therein) or their low metallicity (Kunth and Sargent, 1986)
Some boundary effects in quantum field theory
We have constructed a quantum field theory in a finite box, with periodic
boundary conditions, using the hypothesis that particles living in a finite box
are created and/or annihilated by the creation and/or annihilation operators,
respectively, of a quantum harmonic oscillator on a circle. An expression for
the effective coupling constant is obtained showing explicitly its dependence
on the dimension of the box.Comment: 12 pages, Late
Generalized quantum field theory: perturbative computation and perspectives
We analyze some consequences of two possible interpretations of the action of
the ladder operators emerging from generalized Heisenberg algebras in the
framework of the second quantized formalism. Within the first interpretation we
construct a quantum field theory that creates at any space-time point particles
described by a q-deformed Heisenberg algebra and we compute the propagator and
a specific first order scattering process. Concerning the second one, we draw
attention to the possibility of constructing this theory where each state of a
generalized Heisenberg algebra is interpreted as a particle with different
mass.Comment: 19 page
Pengaruh Imbalan, Motivasi dan Kepuasan Kerja terhadap Kinerja Pegawai Kejaksaan Agung dan Kejaksaan Distrik Dili
Penelitian ini memiliki tujuan untuk mengetahui pengaruh imbalan, motivasi kerja, dan kepuasan kerja terhadap kinerja pegawai. Penelitian ini mengambil lokasi di Kantor Kejaksaan Agung Timor-Leste dan Kejaksaan Distrik Dili, dengan menggunakan seluruh 90 pegawai sebagai responden penelitian. Pengujian hipotesis mengungkapkann bahwa imbalan berpengaruh secara positif dan signfiikan terhadap kinerja pegawai Kejaksaan Agung dan Kejaksaan Distrik Dili. Variabel Motivasi berpengaruh secara positif dan signfiikan terhadap kinerja pegawai Kejaksaan Agung dan Kejaksaan Distrik Dili. Variabel kepuasan Kerja berpenaruh positif signifikan terhadap kinerja pegawai Kejaksaan Agung dan Kejaksaan Distrik Dili
Construction of a non-standard quantum field theory through a generalized Heisenberg algebra
We construct a Heisenberg-like algebra for the one dimensional quantum free
Klein-Gordon equation defined on the interval of the real line of length .
Using the realization of the ladder operators of this type Heisenberg algebra
in terms of physical operators we build a 3+1 dimensional free quantum field
theory based on this algebra. We introduce fields written in terms of the
ladder operators of this type Heisenberg algebra and a free quantum Hamiltonian
in terms of these fields. The mass spectrum of the physical excitations of this
quantum field theory are given by , where denotes the level of the particle with mass in an infinite
square-well potential of width .Comment: Latex, 16 page
Predicting the extinction of Ebola spreading in Liberia due to mitigation strategies
The Ebola virus is spreading throughout West Africa and is causing thousands of deaths. In order to quantify the effectiveness of different strategies for controlling the spread, we develop a mathematical model in which the propagation of the Ebola virus through Liberia is caused by travel between counties. For the initial months in which the Ebola virus spreads, we find that the arrival times of the disease into the counties predicted by our model are compatible with World Health Organization data, but we also find that reducing mobility is insufficient to contain the epidemic because it delays the arrival of Ebola virus in each county by only a few weeks. We study the effect of a strategy in which safe burials are increased and effective hospitalisation instituted under two scenarios: (i) one implemented in mid-July 2014 and (ii) one in mid-August—which was the actual time that strong interventions began in Liberia. We find that if scenario (i) had been pursued the lifetime of the epidemic would have been three months shorter and the total number of infected individuals 80% less than in scenario (ii). Our projection under scenario (ii) is that the spreading will stop by mid-spring 2015.H.E.S. thanks the NSF (grants CMMI 1125290 and CHE-1213217) and the Keck Foundation for financial support. L.D.V. and L.A.B. wish to thank to UNMdP and FONCyT (Pict 0429/2013) for financial support. (CMMI 1125290 - NSF; CHE-1213217 - NSF; Keck Foundation; UNMdP; Pict 0429/2013 - FONCyT)Published versio
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