869 research outputs found

    The Initial Value Problem For Maximally Non-Local Actions

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    We study the initial value problem for actions which contain non-trivial functions of integrals of local functions of the dynamical variable. In contrast to many other non-local actions, the classical solution set of these systems is at most discretely enlarged, and may even be restricted, with respect to that of a local theory. We show that the solutions are those of a local theory whose (spacetime constant) parameters vary with the initial value data according to algebraic equations. The various roots of these algebraic equations can be plausibly interpreted in quantum mechanics as different components of a multi-component wave function. It is also possible that the consistency of these algebraic equations imposes constraints upon the initial value data which appear miraculous from the context of a local theory.Comment: 8 pages, LaTeX 2 epsilo

    The Value of Singularities

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    We point out that spacetime singularities play a useful role in gravitational theories by eliminating unphysical solutions. In particular, we argue that any modification of general relativity which is completely nonsingular cannot have a stable ground state. This argument applies both to classical extensions of general relativity, and to candidate quantum theories of gravity.Comment: 5 pages, no figures; a few clarifying comments adde

    Avalanche boron fusion by laser picosecond block ignition with magnetic trapping for clean and economic reactor

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    After the very long consideration of the ideal energy source by fusion of the protons of light hydrogen with the boron isotope 11 (boron fusion HB11) the very first two independent measurements of very high reaction gains by lasers basically opens a fundamental breakthrough. The non-thermal plasma block ignition with extremely high power laser pulses above petawatt of picosecond duration in combination with up to ten kilotesla magnetic fields for trapping has to be combined to use the measured high gains as proof of an avalanche reaction for an environmentally clean, low cost and lasting energy source as potential option against global warming. The unique HB11 avalanche reaction is are now based on elastic collisions of helium nuclei (alpha particles) limited only to a reactor for controlled fusion energy during a very short time within a very small volume.Comment: 11 pages, 6 figures, Submitted to Proceedings 2nd Symposium High Power Laser Science and Engineering, 14-18 MARCH 2016, Suzhou/Chin

    Directives for Sustainability Management in the Amazon Forest Economy

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    This paper presents drivers to promote sustainable management in the forest economy in Rondocirc;nia, as an alternative to the traditional economic approach to forest resources. Therefore, the study questions how the forest management in the State of Rondocirc;nia can contribute as an alternative to the predatory use of the forest, mitigating the impact on the Amazonian socio-biodiversity. The general objective is to generate knowledge about the exploitation of timber and non-timber resources in Rondocirc;nia, and has as specific goals to promote the survey of the theme, as indicated in theory and according to practices carried out in the State of Rondocirc;nia / Brazil (1); to discuss the main characteristics of forest management with sustainability, promoting its multifaceted characterization in the face of commercial and intercropping (2); and finally, to address the alternative uses of Forest Management, indicating drivers and adaptive the spatial conditions of the Amazon region, specifically Rondocirc;nia (3). This research is characterized as qualitative with the method of content analysis; involved the raising of theoretical bases that describe the scenario of study and consultation of specialists, to promote the proficient contextualization, analysis, and inference of the results. It was verified that the drivers for sustainable forest management are alternatives to the predatory use of natural resources, providing the use of multiple conservative mechanisms, interrelating profitability and sustainable development, in favor of the emergence and consolidation of an integrated forest production chain with diversified industrial systems. This work is of interest to the scientific community and rural managers and producers since it offers a contribution to the management of forest resources with sustainability

    From extended phase space dynamics to fluid theory

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    We derive a fluid theory for spin-1/2 particles starting from an extended kinetic model based on a spin-projected density matrix formalism. The evolution equation for the spin density is found to contain a pressure-like term. We give an example where this term is important by looking at a linear mode previously found in a spin kinetic model.Comment: 4 page

    Topological Excitations in Compact Maxwell-Chern-Simons Theory

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    We construct a lattice model of compact (2+1)-dimensional Maxwell-Chern- Simons theory, starting from its formulation in terms of gauge invariant quantities proposed by Deser and Jackiw. We thereby identify the topological excitations and their interactions. These consist of monopolo- antimonopole pairs bounded by strings carrying both magnetic flux and electric charge. The electric charge renders the Dirac strings observable and endows them with a finite energy per unit length, which results in a linearly confining string tension. Additionally, the strings interact via an imaginary, topological term measuring the (self-) linking number of closed strings.Comment: harvmac, CERN-TH. 6906/93, DFUPG 80/9

    On the Class of Possible Nonlocal Anyon-Like Operators and Quantum Groups

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    We find a class of nonlocal operators constructed by attaching a disorder operator to fermionic degrees of freedom, which can be used to generate q-deformed algebras following the Schwinger approach. This class includes the recently proposed anyonic operators defined on a lattice.Comment: 10 pages (plain latex), HU-SEFT R 1993-9, to be published in Journal of Physics A: Math. and General, Letters to the Edito

    Efficacy and Safety of Mefloquine, Artesunate, Mefloquine-Artesunate, and Praziquantel against Schistosoma haematobium: Randomized, Exploratory Open-Label Trial

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    Background. Morbidity control of schistosomiasis relies on a single drug, praziquantel. The antimalarial drug mefloquine possesses interesting antischistosomal properties, yet no clinical studies have been performed. Methods. We conducted a randomized, exploratory open-label trial to assess the efficacy and safety of mefloquine (25 mg/kg), artesunate (3 doses of 4 mg/kg), mefloquine-artesunate (3 doses of 100 mg artesunate plus 250 mg mefloquine), and praziquantel (40 mg/kg) against Schistosoma haematobium. The effects on Schistosoma mansoni, malaria parasitemia, soil-transmitted helminths, and intestinal protozoa were also determined. Results. A total of 83 S. haematobium-infected schoolchildren were included in the study. Cure rates of mefloquine, artesunate, mefloquine-artesunate, and praziquantel against S. haematobium at day 26 after treatment were 21%, 25%, 61%, and 88%, respectively. Both mefloquine-artesunate and praziquantel resulted in egg reduction rates >95%. Significantly lower egg reduction rates were seen in the artesunate (85%) and mefloquine groups (74%). In children coinfected with S. mansoni, praziquantel and mefloquine-artesunate, but not mefloquine and artesunate alone, resulted in high cure rates and egg reduction rates. Mefloquine, artesunate, and mefloquine-artesunate completely cured infections due to Plasmodium falciparum. No effects were found against soil-transmitted helminths and intestinal protozoa. Abdominal pain was the most frequent adverse event, with a higher incidence among children treated with mefloquine (89%), mefloquine-artesunate (83%), and artesunate (60%) than among children treated with praziquantel (46%). Conclusions. The high efficacy of mefloquine-artesunate against S. haematobium warrants further investigation. Individuals coinfected with Plasmodium and Schistosoma who were treated with a mefloquine-artesunate combination against malaria might have a dual benefit: clearance of malaria parasitemia and reduction of schistosomiasisrelated morbidity. Clinical trials registration. Current Controlled Trials identifier: ISRCTN0649876
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