Lorentzian Vacuum Transitions in Ho\v{r}ava-Lifshitz Gravity

The vacuum transition probabilities for a Friedmann-Lema\^itre-Robertson-Walker universe with positive curvature in Ho\v{r}ava-Lifshitz gravity in the presence of a scalar field potential in the Wentzel-Kramers-Brillouin approximation are studied. We use a general procedure to compute such transition probabilities using a Hamiltonian approach to the Wheeler-DeWitt equation presented in a previous work. We consider two situations of scalar fields, one in which the scalar field depends on all the spacetime variables and other in which the scalar field depends only on the time variable. In both cases analytic expressions for the vacuum transition probabilities are obtained and the infrared and ultraviolet limits are discussed for comparison with the result obtained by using general relativity. For the case in which the scalar field depends on all spacetime variables we obtain that in the infrared limit it is possible to obtain a similar behavior as in general relativity, however in the ultraviolet limit the behavior found is completely opposite. Some few comments about possible phenomenological implications of our results are given. One of them is a plausible resolution of the initial singularity. On the other hand for the case in which the scalar field depends only on the time variable, the behavior coincides with that of general relativity in both limits, although in the intermediate region the probability is slightly altered.Comment: 26 pages, 2 figures. Some references adde

Scalar field inflation driven by a modification of the Heisenberg algebra

We study the modifications induced on scalar field inflation produced by considering a general modification of the Heisenberg algebra. We proceed by modifying the Poisson brackets on the classical theory whenever the corresponding quantum commutator is modified. We do not restrict ourselves to a specific form for such modification, instead we constrain the functions involved by the cosmological behaviour of interest. We present whenever possible the way in which inflation can be realized approximately via three slow roll Hubble parameters that depend on the standard slow roll parameters in a very different form than in the usual case and that can be less restrictive. Furthermore we find a general analytical solution describing an expanding universe with constant Hubble parameter that generalizes the standard cosmological constant case by restricting the form of the modification of the Heisenberg algebra. It is found that even if such modification can be neglected in some limit and the cosmological constant is set to zero in that limit, the exponential expansion is present when the modification is important. Thus an appropriate modification of the Heisenberg algebra is sufficient to produce an exponentially expanding universe without the need of any other source.Comment: 34 pages, 1 figur

“TRATAMIENTO QUIRURGICO DE LAS FRACTURAS EN EDAD PEDIATRICA CON CLAVOS TEN´S”

En el Hospital General Regional 220 del IMSS, Toluca, Edo México, se realizó un estudio retrospectivo, transversal, con unidad de análisis individual y fuente de datos primario, de fracturas en edad pediátrica, en edades de 3 a 14 años, tratadas con clavos intramedulares (TENS). Se trataron 50 fracturas en 48 pacientes, del 1ro de Enero del 2010 al 1ro de Marzo del 2012. Se trataron 48 pacientes, 30 del género masculino (62.5%) y 18 del femenino (37.5%), en una relación de 1.6:1, masculino:femenino, con un total de 50 fracturas, presentándose en 2 pacientes fractura ipsilateral de fémur y tibia. El hueso que más frecuentemente se lesionó fue el fémur con 22 fracturas (44%), el húmero con 7 (14%), 5 hombres y 2 mujeres, y el segmento radio cubital con un 8%, 3 del sexo masculino y uno del femenino. Solo 11 pacientes (22.9%) ameritaron rehabilitación, el 77.08% no la requirieron y presentaron una movilidad completa. La consolidación ósea total estuvo en promedio a las 7.5 semanas, siendo de 6 a 12 semanas posterior a la cirugía. Y al término de esta se evaluaron radiográficamente si existían datos de angulación residual, presentándose en 3 pacientes (6.25%), de los cuales un 2.08% fue el más importante en una fractura de húmero con 12 grados de desviación en varo. El tratamiento quirúrgico con clavos elásticos de titanio (TENS) en la edad pediátrica, es una buena técnica quirúrgica, ya que no se realiza en forma cruenta, siendo su indicación principal para tratar las fracturas de la diáfisis de los huesos largos en pacientes de los 4 a los 14 años, aunque se pueden usar en un rango menor o mayor dependiendo del tipo y localización de la lesión, con la grandes ventajas de que es una técnica mínima invasiva, percutánea, aceptada estéticamente, de un bajo costo, con mínimo o nulo riesgo de infección. Palabras Clave: Fractura, Diáfisis, clavo elástico, Tens. Nivel de Evidencia: II

Urban Sprawl in the Mediterranean Urban Regions in Europe and the Crisis Effect on the Urban Land Development: Madrid as Study Case

The middle of 2007 saw the beginning of a worldwide financial crisis that led to a sharp reduction in investment based on construction and urban development. This new situation is generating a new process, characterised by a slowdown that has almost reached a standstill when compared with the frenzied development of previous decades. In order to analyse these processes, this study examines urban land use changes and the urban growth rate and spatial dynamics of the metropolitan region of Madrid. The analysis has been carried out on a large scale between two periods (2000?2006 and 2006?2009) using a regional land use geodatabase. The results show the changes in the urban land use dynamics that took place over these two periods that could characterise the cities of Mediterranean Europe, where contrarily to the general pattern in Europe built-up areas are combining scattered built-up areas with new aggregated compact developments

Invertibles in topological rings: a new approach

Every element in the boundary of the group of invertibles of a Banach algebra is a topological zero divisor. We extend this result to the scope of topological rings. In particular, we define a new class of semi-normed rings, called almost absolutely semi-normed rings, which strictly includes the class of absolutely semi-valued rings, and prove that every element in the boundary of the group of invertibles of a complete almost absolutely semi-normed ring is a topological zero divisor. To achieve all these, we have to previously entail an exhaustive study of topological divisors of zero in topological rings. In addition, it is also well known that the group of invertibles is open and the inversion map is continuous and C-differentiable in a Banach algebra. We also extend these results to the setting of complete normed rings. Finally, this study allows us to generalize the point, continuous and residual spectra to the scope of Banach algebras

Influência da natação e do ciclismo sobre as respostas fisiológicas durante a corrida no triathlon

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Desportos, Programa de Pós-graduação em Educação Física, Florianópolis, 2010O estudo teve como objetivo determinar as respostas cardiorrespiratórias (VO2 e FC) e metabólicas (lactato) de triatletas treinados durante um simulado de TO e analisar os efeitos fisiológicos da natação e do ciclismo na máxima fase estável de lactato (MFEL) da corrida. Onze triatletas treinados (32,2 ± 4,8 anos; 75 ±6,2 kg; 178 ± 0,1cm) realizaram em dias diferentes os seguintes testes: 1) protocolo incremental na esteira rolante para a determinação do VO2max, IVO2max e LAn; 2) protocolo incremental realizado na própria bicicleta do atleta acoplada a um ciclossimulador para determinar o VO2max, IVO2max e 70%Pmax; 3) três a cinco testes para determinação da MFEL; 4) duas simulações da prova de TO, uma delas envolvendo a sucessão ciclismo-corrida (CC), e outra envolvendo a seqüência completa de natação-ciclismo-corrida (N-C-C). Em relação ao comportamento do VO2 ao longo dos 60 minutos de ciclismo foi encontrada diferença significativa apenas para o simulado C-C (sC-C) (41,8±6,0 no minuto 5 e 47,1±6,4 mL.Kg-1.min-1 no minuto 60). A FC apresentou comportamento similar ao do VO2, apresentando diferença significativa ao longo do tempo apenas para o sC-C (141,9±9,9 no minuto 5 e 156,8±8,1 bpm no minuto 60). Quando comparadas as duas situações de ciclismo foi observada diferença significante entre os minutos iniciais, 5, 10, 15 e 30. Para a [Lac] no sC-C foi encontrada diferença significativa entre os valores iniciais (1,5±0,6) e os minutos 20 (3,5±1,4), 40 (4,0±2,5) e 60 (3,7±1,8) e para o sN-CC foi encontrada diferença significativa entre os valores iniciais (5,8±1,6), 20 (4,8±2,3) e 60 (4,2±1,9) minutos. Quando realizada a análise entre os simulados foi encontrada diferença significativa apenas no início e aos 20 minutos. Nas três condições analisadas da corrida (controle, C-C, N-C-C) não foram observadas diferenças significativas para VO2 entre os simulados, porém quando analisadas separadamente foi encontrada diferença significativa ao longo do tempo para as três condições. A FC apresentou comportamento similar ao do VO2 ao longo do tempo para as três situações. Por outro lado, quando comparada entre as três situações, para cada intervalo de tempo, não foi encontrada diferença significativa. Para as [Lac] foi encontrada diferença significativa ao longo do tempo (minuto inicial, 10 e 30) para as três condições. Quando comparada entre os grupos foi encontrada diferença significativa do minuto inicial do controlo (1,60±0,31) e sC-C (2,91±1,31mmol.L-1) com o sN-C-C (4,10±1,39). Além do minuto dez do controlo (3,57±1,07) e sC-C (4,21±1,23) em relação ao dez do sN-C-C (5,28±1,88). E ainda do minuto 30 do controle (4,27±0,67) e sC-C (4,02±1,08) para o sN-C-C (5,44±1,66 mmol.L-1). Conclui-se que o exercício prévio de natação e ciclismo não interfere nas respostas cardiorespiratórias (VO2 e FC) da corrida realizada em vMFEL.The pourpose of this study was to determine cardiorespiratory and metabolic responses (VO2max, HR and [Lac]) of trained triathletes during a simulated olympic distance triathlon and analyze the physiological effect of swimming and the cycling with running at MLSS. Eleven trained triathletes (32,2 ± 4,8 years old; 75 ±6,2 kg; 178 ± 0,1cm) performed the following tests in different days: 1) treadmill incremental protocol to evaluate VO2max, IVO2max and LAn; 2) cycle ergometer incremental test with own bicycle to determine VO2max, IVO2max and 70%Pmax; 3) five tests to determine the MLSS; 4) two simulated OT races: a cycling-running (CR) and a swimm-cycle-running triathlon (SCR). When VO2max response during the 60 minutes of cycling was analyzed, a significant difference was found only for the simulated CR(41,8±6,0 at minutes 5 and 47,1±6,4mL.Kg-1.min-1 at minute 60). Similarly, HR presented a significant difference for CR (141,9±9,9 at minute 5 and, 156,8±8,1 bpm at minute 60). When the two distinctive cycling situations were compared, there was a significant difference between the initial minutes, 5, 10, 15 and 30. There was a significant difference for [Lac] in CR, between the initial values (1,5±0,6) and minutes 20 (3,5±1,4), 40 (4,0±2,5) and 60 (3,7±1,8); and for SCR, between the initial values (5,8±1,6), minute 20 (4,8±2,3) and minute 60 (4,2±1,9). When the simulated tests were compared, there was a significant difference only at minute 20. In the three situations of simulated running analyzed control, CR, SCR), significant differences for VO2 were not observed, however when analyzed separately, a significant difference was found throughout the time for all conditions. A similar behavior in HR, to the one of VO2, during the time for the three circumstances. On the other hand, when the situations were compared for each time interval, no significant difference was found. For [Lac], a significant difference was found throughout the time (initial, 10 and 30 minutes) for the three settings. When compared between groups, a significant difference for initial minute of the control was found (1,60±0,31), and CR (2,91±1,31mmol. L-1) with SCR (4,10±1,39); as well as at minute ten of the control (3,57±1,07) and CR (4,21±1,23) in association to minute ten of SCR (5,28±1,88) and at minute 30 of the control (4,27±0,67) and CR (4,02±1,08) to SCR (5,44±1,66 mmol. L-1). The author can conclude that the previous exercise of swimming and cycling does not intervene with the cardiorespiratory answers (VO2max and HR) with running at vMLSS

In flight Management - Committing to Destination

The present Brazilian regulation is not precise whether the alternate fuel could or could not be used to proceed to the original destination without compromising the emergency fuel, once exact specific requirements are met. As a result of unclear directrices, each major airline in Brazil comprehends and applies the ICAO recommendation in its way. Such a non-standardized interpretation of the current regulation certainly compromises both the airline industry\u27s safety and efficiency in the country. Therefore, this research proposes a more comprehensive and clear text for the Brazilian rules, encouraging airlines to adhere to what the ICAO recommendation preconizes widely