Lorentz invariance and quantum gravity: an additional fine-tuning problem?

Trying to combine standard quantum field theories with gravity leads to a breakdown of the usual structure of space-time at around the Planck length, 1.6*10^{-35} m, with possible violations of Lorentz invariance. Calculations of preferred-frame effects in quantum gravity have further motivated high precision searches for Lorentz violation. Here, we explain that combining known elementary particle interactions with a Planck-scale preferred frame gives rise to Lorentz violation at the percent level, some 20 orders of magnitude higher than earlier estimates, unless the bare parameters of the theory are unnaturally strongly fine-tuned. Therefore an important task is not just the improvement of the precision of searches for violations of Lorentz invariance, but also the search for theoretical mechanisms for automatically preserving Lorentz invariance.Comment: 4 pages, 1 figure. V.4: Updates of references; slightly shortened to journal length limits for Phys. Rev. Let

Mejoremos nuestra ortografía

La presente investigación busca identificar el porqué del problema ortográfico en los estudiantes del grado 9 — 6 del INEM Simón Bolívar. Se llevan a cabo una serie de actividades para trabajar en este aspecto, con el propósito que los estudiantes mejoren su nivel ortográfico de una manera diferente, en un ambiente lúdico y creativo y de esta manera enfocar mejor el estudio del idioma español, permitiendo al estudiante desarrollar sus habilidades ortográficas en el salón de clases con esto se busca Mejorar la expresión escrita a través de la práctica creativa de la ortografía

Design of a Mobile Application to Prevent Bullyng in High School Students

Currently bullying is one of the most frequent problems that occur in educational institutions, for that with the help of technology we wanted to implement in this research as prevention of bullying. Therefore, the goal is to design a mobile application to prevent bullying in high school students. Likewise, the A.D.D.I.E. methodology was used: Analysis, Design, Development, Implementation and Evaluation. In the same way, a survey was carried out with 15 high school students from different schools, to know if they have ever been victims of bullying, perhaps by their other classmates. It is recommended in the future to continue research and develop technological solutions for this problem and other social problems that affect many countries

Effects of Superdispersant-25 on the sorption dynamics of naphthalene and phenanthrene in marine sediments

Acknowledgements: The authors acknowledge the assistance of Mike Mcgibbon in analysing carbon content, the crews of the MRV Scotia and MRV Temora for sample collection. Dr. Hedda Weitz and Prof. Graeme Patton are thanked for facilitating access to laboratory space and equipment. Funding information: LJP was funded through MarCRF funds for a PhD project designed by UW, JA and AG and awarded to LJP.Peer reviewedPostprin

Engineering the optical properties of silicon using sub-wavelength structures

In most integrated optics platforms, including silicon-on-insulator, only minor modifications in refractive index are possible. The geometry of the waveguiding structure is thus the only degree of freedom for the design of devices. The use of sub-wavelength gratings (SWGs), i.e. structures that are small enough to suppress diffraction effects, enables local engineering of both refractive index and dispersion, thereby opening new possibilities for device design. Here we present some of the recent advances in refractive index and dispersion engineering using silicon SWGs, focussing on ultra-broadband and compact multimode interference couplers and directional couplersThis work was supported by the Spanish Ministerio de Ciencia (project TEC2009-10152), the European Mirthe project (FP7-2010-257980), and the Universidad de Málaga - Campus de Excelencia Internacional Andalucìa Tech

Estudio situacional de (Mycobacterium bovis), en bufalos (Bubalus bubalis), en la Empresa Aceitera San Jose S.A., municipio de El Rama (RACCS) - Nicaragua en el año 2021

El presente trabajo se realizó en la empresa aceitera San José S.A, del municipio El Rama Nicaragua, es un estudio situacional, con el objetivo de diagnosticar el microorganismo (Mycobacterium bovis) en Búfalos (Bubalus bubalis), a través de la prueba de tuberculina. Actualmente a nivel nacional el Instituto de Protección y Sanidad Agropecuaria, (IPSA), lleva a cabo un plan de erradicación de tuberculosis, de tal manera las especies que más se realizan dicho diagnóstico es a los bovinos, siendo el municipio El Rama un lugar donde se encuentran empresas aceiteras de Nicaragua y utilizan a los búfalos como animales de tracción, (halar carretas con frutos de palma africana), estos animales no son común mente muestreados en nuestro país. Los búfalos son rumiantes silvestres susceptibles a dicha enfermedad, es por ello que tomamos la consideración de realizar un diagnóstico situación de tuberculosis, siendo una enfermedad de notificación obligatoria y problema de salud pública. Se tomó un muestreo del 50 % de la población bufalina, considerando las siguientes variables: categoría, edad, sexo y raza. Se empleó el diagnóstico del P.P.D. (Derivado Protéico Purificado), en el pliegue ano-caudal, con la aplicación de 0,1 ml, vía intradérmica, posterior de las 72 horas de aplicación, se realizó la revisión de la sensibilidad intradérmica por tuberculina. No se documentó ningún búfalo reactor al agente zoonótico Mycobacterium bovis, en la empresa aceitera San José S.A del municipio El Rama

The effect of chemical dispersant concentration on hydrocarbon mobility through permeable North-East Scotland sands

The authors acknowledge Paul Hallett and Annette Raffan for granting access to and training on the tensiometer, respectively. Cruickshank Analytical Lab staff are acknowledged for assistance in carbon content analysis. The Marine Collaboration Research Forum is acknowledged for funding LJP's PhD project. BP are acknowledged for providing Schiehallion crude oil.Peer reviewedPostprintPostprin

Nutritional Value, Methods for extraction and Bioactive Compounds of Quinoa

Quinoa (Chenopodium quinoa Willd.) is a crop belonging to the Chenopodiaceae family that originated in the high Andean region of South America. Currently, the main producers of quinoa are Bolivia and Peru; this crop groups around 250 species and 3000 varieties. It has a high adaptability, which allows it to be cultivated in cold climates in the high Andean regions, as well as in subtropical conditions, and grows from sea level to more than 4000 meters above sea level. Due to its high nutritional value and nutritional properties, quinoa is considered “one of the grains of the 21st century.” It is high in protein without gluten, polyunsaturated fatty acids, carbohydrates, vitamins, minerals, and fiber, as well as high levels of bioactive compounds such as flavonoids, phenolic acids, bioactive peptides, phytosteroid betalains, phytosterols, and saponins. From quinoa, a protein concentrate of high biological value can be extracted due to its content of the nine essential amino acids, as well as an oil with high antioxidant activity due to its high levels of tocopherols. These by-products have a high economic and commercial value and can be produced on an industrial scale for use in the food, cosmetic, and pharmaceutical industries