Finite size effects in ferromagnetic spin chains and quantum corrections to classical strings

N=4 supersymmetric Yang-Mills operators carrying large charges are dual to semiclassical strings in AdS_5xS^5. The spectrum of anomalous dimensions of very large operators has been calculated solving the Bethe ansatz equations in the thermodynamic limit, and matched to energies of string solitons. We have considered finite size corrections to the Bethe equations, that should correspond to quantum effects on the string side.Comment: 18 pages. Latex. v2: Misprints corrected, expanded discussions with comments on end point effects, and updated referenc

Diseño e implementación de combinadores de potencia para amplificador LINC @ 868MHz

The ISM is a free band generally used in the environmental scientific and medical study. The regulation depends on the government of each country. This study is focused on the European¡¯s level frequency of 868 MHz, this frequency does not require standards or permissions, as long as they do not exceed the regulations. The project was based on the realization of a LINC transmitter with class E amplifiers made of passive matching networks. Also, the design and production of three combiners: Hybrid 90¨¬, Wilkinson and Chireix. In this project we have seen the different existing types of amplifiers (Class A, Class B ...) and the two main transistors that we can find in the market (BJT and FET). The amplifier¡¯s design was done using the ADS program from Agilent, and to characterize matching networks we have used the Smith Chart and ADS LineCalc. The first thing was find the polarization voltages, to characterize the S parameters of the transistor. The stability calculations have been made as theoretical as graphically (ADS). Matching networks are realized with passive elements such as coils and capacitors, that has been the difference of previous studies. At this point of the project the tunning tool was used to refine the results. The Bias Network were designed with shock coils and decoupling capacitors. The last step was the design of the layout with ADS software and then assembled. The other branch of the study has been the design and implementation of three combiners, for the simulation of both the ADS program was also used and finally took the design to a board. The results obtained for the amplifier with matching networks made of passive elements were good only for one channel. For this reason we have had to continue the combiners study with a project implemented earlier by another student, made with ¥ë / 4 lines. As we have seen in the laboratory, the Chireix combiner is positioned as the most efficient and which allows the maximum gain. Future studies may try to improve the performance of a class E type LINC amplifier with stable matching networks made of passive elements, as well as, improve the efficiency of the Chireix combiner and open new ways of study.La banda ISM es una banda libre que generalmente se usa en el estudio medioambiental, científico y médico. La normativa depende del gobierno de cada territorio. Este estudio se ha centrado en el ámbito europeo a la frecuencia de 868 MHz. Esta frecuencia no requiere de estándares ni permisos siempre que no supere la normativa

Intervenção educativa sobre verminoses na ESFII Alto da Boa Vista no município Olho D'água do Casado/Alagoas

O município Olho d'Água do Casado localiza-se a oestedo estado de Alagoas. Apresenta um Índice de Desenvolvimento Humano (IDH): 0,525 pelo que está situado em uma faixa de desenvolvimento humano baixa (0,5 e 0,599). O alto índice de verminose é um dos principais problemas de saúde do município especificamente na equipe II do Programa de Saúde da Família que faz atendimento na área rural, nossa equipe tem uma população cadastrada de 1758 habitantes, com um nível de alfabetização de 80,53%. Desse total 721 são menores de 19 anos (41.01%); 93.48 recebem água de fontes não tratadas. A população tem pouca noção de higiene sobre a qualidade da água de beber, devido a hábitos arraigados sobre a forma de ferver a água, a lavagem de frutas e vegetais, o não uso de calçado nas crianças, entre outros. Por esses motivos constatou-se a necessidade de elaborar um plano de ação com ênfase educativa e promocional para diminuir o alto índice de verminoses em nossa área. Para elaboração do plano de intervenção foi estabelecida uma priorização dos problemas encontrados pela estimativa rápida logo, analisou-se as influências negativas para a população. Assim, com base nos problemas e nós críticos, foram desempenhadas as operações e possíveis soluções, levando em conta os resultados esperados, o produto e os recursos necessários. Todo isso com o objetivo de realizar ações educativas para modificar estilos de vida e hábitos higiênicos na população e assim aumentar o nível de informação sobre como se transmite a doença, suas complicações e como evitar

Temperature dependent dynamic and static magnetic response in magnetic tunnel junctions with Permalloy layers

Ferromagnetic resonance and static magnetic properties of CoFe/Al2O3/CoFe/Py and CoFe/Al2O3/CoFeB/Py magnetic tunnel junctions and of 25nm thick single-layer Permalloy(Py) films have been studied as a function of temperature down to 2K. The temperature dependence of the ferromagnetic resonance excited in the Py layers in magnetic tunnel junctions shows knee-like enhancement of the resonance frequency accompanied by an anomaly in the magnetization near 60K. We attribute the anomalous static and dynamic magnetic response at low temperatures to interface stress induced magnetic reorientation transition at the Py interface which could be influenced by dipolar soft-hard layer coupling through the Al2O3 barrier

The elementary excitations of the exactly solvable Russian doll BCS model of superconductivity

The recently proposed Russian doll BCS model provides a simple example of a many body system whose renormalization group analysis reveals the existence of limit cycles in the running coupling constants of the model. The model was first studied using RG, mean field and numerical methods showing the Russian doll scaling of the spectrum, E(n) ~ E0 exp(-l n}, where l is the RG period. In this paper we use the recently discovered exact solution of this model to study the low energy spectrum. We find that, in addition to the standard quasiparticles, the electrons can bind into Cooper pairs that are different from those forming the condensate and with higher energy. These excited Cooper pairs can be described by a quantum number Q which appears in the Bethe ansatz equation and has a RG interpretation.Comment: 36 pages, 12 figure

Dendron-functionalised hyperbranched bis-MPA polyesters as efficient non-viral vectors for gene therapy in different cell lines

Gene therapy has become a relevant tool in the biomedical field to treat or even prevent some diseases. The effective delivery of genetic material into the cell remains a crucial step to succeed in this purpose. In the search for efficient non-viral vectors, a series of amino-terminated dendronized hyperbranched polymers (DHPs) of different generations based either on bis-MPA or bis-GMPA have been designed. All of them have demonstrated an accurate ability to complex two types of genetic materials, a plasmid DNA and a siGFP, yielding dendriplexes. Moreover, some of them have proved to be able to deliver the genetic material inside the cells, resulting in the effective accomplishment of the desired genetic modification and improving the activity of some commercial transfection reagents. Different cell lines, including cancer and mesenchymal stem cells, have been studied here to evaluate the ability of DHPs as vectors for transfection. Treatments based on mesenchymal stem cells are gaining importance due to their pluripotency. Thus, it is of special relevance to introduce a genetic modification into a mesenchymal cell line as it allows it to act over a wide spectrum of tissues after inducing cellular differentiation

Phase signal analysis for high-sensitive temperature fiber-optic external Fabry-Perot-cavity sensor

We experimentally demonstrate a highly temperature-sensitive external Fabry-Perot cavity. The interferometric structure is composed of an air-microcavity; its fabrication uses a microcapillary and UV polymer. A temperature sensitivity close to 5.7 nm/◦C is achieved with suitable linearity (0.9896) and minimal hysteresis; a phase analysis technique is proposed and applied to overcome the trade-off between sensitivity and range of operation. This technique provides a competitive sensitivity (0.84 rad/◦C), good linearity (0.9934), and a range of operation from 25◦C to 41◦C.</p

Actividad física en niños con síndrome de down estudio de caso.

La investigación se planteó con una propuesta metodológica de actividad física para dos sujetos en condición de síndrome de Down. este proyecto cuenta con la descripción del problema los objetivos planteados, la investigación de los temas a trabajar, las leyes en las cuales podemos basarnos, el diseño metodológico y la propuesta de actividades a realizar