2,028 research outputs found
Rotating Resonator-Oscillator Experiments to Test Lorentz Invariance in Electrodynamics
In this work we outline the two most commonly used test theories (RMS and
SME) for testing Local Lorentz Invariance (LLI) of the photon. Then we develop
the general framework of applying these test theories to resonator experiments
with an emphasis on rotating experiments in the laboratory. We compare the
inherent sensitivity factors of common experiments and propose some new
configurations. Finally we apply the test theories to the rotating cryogenic
experiment at the University of Western Australia, which recently set new
limits in both the RMS and SME frameworks [hep-ph/0506074].Comment: Submitted to Lecture Notes in Physics, 36 pages, minor modifications,
updated list of reference
Improved test of Lorentz Invariance in Electrodynamics using Rotating Cryogenic Sapphire Oscillators
We present new results from our test of Lorentz invariance, which compares
two orthogonal cryogenic sapphire microwave oscillators rotating in the lab. We
have now acquired over 1 year of data, allowing us to avoid the short data set
approximation (less than 1 year) that assumes no cancelation occurs between the
and parameters from the photon
sector of the standard model extension. Thus, we are able to place independent
limits on all eight and parameters.
Our results represents up to a factor of 10 improvement over previous non
rotating measurements (which independently constrained 7 parameters), and is a
slight improvement (except for ) over results from
previous rotating experiments that assumed the short data set approximation.
Also, an analysis in the Robertson-Mansouri-Sexl framework allows us to place a
new limit on the isotropy parameter of
, an improvement of a factor of 2.Comment: Accepted for publication in Phys. Rev.
Kinetics of recovery from anhydrobiosis in Pratylenchus thornei, Merlinius brevidens and Heterodera avenae from dry field soils and dry roots of the host plant
Le comportement de #Pratylenchus thornei, Merlinius brevidens et #Heterodera avenae dans un sol particulièrement sec du sud de l'Espagne a été étudié, après la saison d'été. Six périodes de récupération, allant jusqu'à 135 h de réhydratation suivie de migration, permettent de récupérer plus de 95 % de la population de #Merlinius - qui semble l'espèce dominante et la plus importante dans la zone considérée - la récupération au taux de 95 %, après culture de blé var, yecora, n'est atteinte qu'après douze périodes, et 279 h, pour autant que toutes les racines présentes dans le sol soient elles aussi traitées. Les #Pratylenchus survivant dans les racines desséchées du blé semblent être la cause de pertes de récolte encore inexpliquées atteignant cette culture. #Heterodera avenae ne paraît jouer qu'un rôle secondaire dans ces sols secs. (Résumé d'auteur
On the field anhydrobiotic ability of Pratylenchis thornei and Merlinius brevidens
La présente étude du comportement anhydrobiotique de #Pratylenchus thornei et de #Merlinius brevidens a été réalisée dans un champ non irrigué de blé cv. Gallareta, variété considérée comme non-hôte ou mauvais hôte pour ces nématodes. #P. thornei paraît plus dépendant de l'humidité du sol que #M. brevidens en ce qui concerne sa récupération après 15 h de migration (réhydratation, réactivation et migration). #M. brevidens sort plus facilement de son état anhydrobiotique. Les schémas d'émergence sont semblables pour les deux nématodes qu'ils soient actifs ou récupérés après une anhydrobiose prononcée. Ces schémas sont par contre différents s'il s'agit d'un stade précoce d'anhydrobiose (anhydrobiose modérée). Les deux nématodes font montre, en relation avec la profondeur du sol, d'une inertie à entrer en anhydrobiose qui paraît dépendre des processus naturels de dessiccation du sol du champ. Cette inertie semble plus prononcée chez #M. brevidens. (Résumé d'auteur
Relativity tests by complementary rotating Michelson-Morley experiments
We report Relativity tests based on data from two simultaneous
Michelson-Morley experiments, spanning a period of more than one year. Both
were actively rotated on turntables. One (in Berlin, Germany) uses optical
Fabry-Perot resonators made of fused silica; the other (in Perth, Australia)
uses microwave whispering-gallery sapphire resonators. Within the standard
model extension, we obtain simultaneous limits on Lorentz violation for
electrons (5 coefficients) and photons (8) at levels down to ,
improved by factors between 3 and 50 compared to previous work.Comment: 5 pages revtex, 2 figure
La institucionalidad de las Juntas Parroquiales Rurales, su perspectiva en el desarrollo político, social y económico ecuatoriano
El reconocimiento para la Junta Parroquial Rural ha perdurado en la historia, con diferentes atribuciones y responsabilidades como la realización de obras, manejo de recursos económicos, arbitraje, conciliación y control de los fondos destinados a las obras en su jurisdicción, así como de intermediaria entre la población las municipales y los consejos provinciales.
Sin embargo, pese a los constantes esfuerzos para desarrollar el país y mejorar el funcionamiento de sus instituciones en la administración pública, todavía subsiste una falta de claridad en los roles de los distintos niveles de gobierno. Cabe mencionar que el Estado está altamente centralizado, buena parte de las decisiones políticas, económicas y sociales se toman en las ciudades de Quito y/o Guayaquil, donde los Ministerios todavía mantienen muchas competencias y responsabilidades que por su cercanía a la ciudadanía deberían ejecutarse con mayor eficiencia y eficacia en los gobiernos seccionales autónomos. Es fundamental conocer que el territorio ecuatoriano es indivisible, que la administración del Estado y su representación política se realiza a través de provincias, cantones, parroquias y circunscripciones territoriales indígenas y afroecuatorianas. En este contexto, la división administrativo seccional de la organización territorial del Estado, se ha reconocido la existencia de dos Regímenes Seccionales: los Dependientes y los Autónomos, estas conforman y constituyen la organización territorial del Ecuador como lo dispone el Título XI de la Constitución de la República del país.1. Diagnóstico y planteamiento del problema 2.Enfoque teórico 3. EL Presupuesto Participativo 4. Normas y principios de Administración Financiera Pública 5. Aplicación Financiera en las Juntas Parroquiales Rurales 6. Conclusiones y Recomendaciones
Energy level shift of quantum systems via the electric Aharonov-Bohm effect
A novel version of the electric Aharonov-Bohm effect is proposed where the
quantum system which picks up the Aharonov-Bohm phase is confined to a Faraday
cage with a time varying, spatially uniform scalar potential. The electric and
magnetic fields in this region are effectively zero for the entire period of
the experiment. The observable consequence of this version of the electric
Aharonov-Bohmn effect is to shift the energy levels of the quantum system
rather than shift the fringes of the 2-slit interference pattern. We show a
strong mathematical connection between this version of the scalar electric AB
effect and the AC Stark effect.Comment: 14 pages revtex, 4 figures. Added references and changes made to
address referee comments. To be published in PR
Recent Experimental Tests of Special Relativity
We review our recent Michelson-Morley (MM) and Kennedy-Thorndike (KT)
experiment, which tests Lorentz invariance in the photon sector, and report
first results of our ongoing atomic clock test of Lorentz invariance in the
matter sector. The MM-KT experiment compares a cryogenic microwave resonator to
a hydrogen maser, and has set the most stringent limit on a number of
parameters in alternative theories to special relativity. We also report first
results of a test of Lorentz invariance in the SME (Standard Model Extension)
matter sector, using Zeeman transitions in a laser cooled Cs atomic fountain
clock. We describe the experiment together with the theoretical model and
analysis. Recent experimental results are presented and we give a first
estimate of components of the parameters of the SME matter
sector. A full analysis of systematic effects is still in progress, and will be
the subject of a future publication together with our final results. If
confirmed, the present limits would correspond to first ever measurements of
some components, and improvements by 11 and 14 orders of
magnitude on others.Comment: 29 pages. Contribution to Springer Lecture Notes, "Special Relativity
- Will it survive the next 100 years ?", Proceedings, Potsdam, 200
- …