2,691 research outputs found
Nonlocality-induced front interaction enhancement
We demonstrate that nonlocal coupling strongly influences the dynamics of
fronts connecting two equivalent states. In two prototype models we observe a
large amplification in the interaction strength between two opposite fronts
increasing front velocities several orders of magnitude. By analyzing the
spatial dynamics we prove that way beyond quantitative effects, nonlocal terms
can also change the overall qualitative picture by inducing oscillations in the
front profile. This leads to a mechanism for the formation of localized
structures not present for local interactions. Finally, nonlocal coupling can
induce a steep broadening of localized structures, eventually annihilating
them.Comment: 4 pages, 6 figure
Logical operations with Localized Structures
We show how to exploit excitable regimes mediated by localized structures
(LS) to perform AND, OR, and NOT logical operations providing full logical
functionality. Our scheme is general and can be implemented in any physical
system displaying LS. In particular, LS in nonlinear photonic devices can be
used for all-optical computing applications where several reconfigurable logic
gates can be implemented in the transverse plane of a single device, allowing
for parallel computing.Comment: 11 pages, 6 figure
Numerical model of solid phase transformations governed by nucleation and growth. Microstructure development during isothermal crystallization
A simple numerical model which calculates the kinetics of crystallization
involving randomly distributed nucleation and isotropic growth is presented.
The model can be applied to different thermal histories and no restrictions are
imposed on the time and the temperature dependencies of the nucleation and
growth rates. We also develop an algorithm which evaluates the corresponding
emerging grain size distribution. The algorithm is easy to implement and
particularly flexible making it possible to simulate several experimental
conditions. Its simplicity and minimal computer requirements allow high
accuracy for two- and three-dimensional growth simulations. The algorithm is
applied to explore the grain morphology development during isothermal
treatments for several nucleation regimes. In particular, thermal nucleation,
pre-existing nuclei and the combination of both nucleation mechanisms are
analyzed. For the first two cases, the universal grain size distribution is
obtained. The high accuracy of the model is stated from its comparison to
analytical predictions. Finally, the validity of the
Kolmogorov-Johnson-Mehl-Avrami model is verified for all the cases studied
Checklist of marine Crustacea Decapoda (excluded Brachyura) from Iberian Peninsula
An actualized and annotated checklist of marine Crustacea Decapoda (excluded Brachyura) from Iberian Peninsula and by sectors (Northern Spain (Gulf of Biscay to Galicia) - West Portugal - Gulf of Cádiz (S Portugal- SW Spain: Cape San Vicente to Gibraltar Strait) - Alborán Sea - Eastern Mediterranean Spain (Baleares-Levante)) is provided. Systematic changes and synonymies, new records, introduced species by anthropogenic activities and characterization of the spatial distribution of species are commented. In total 292 decapods species (not including Brachyura), belonging to 134 genera and 42 families, are cited along Iberian waters. Of these, 114 were not found by Zariquiey Álvarez (1968). The richest families are Paguridae, Hippolytidae and Palemonidae (with 28, 21 and 17 species respectively). By sectors, the Gulf of Cadiz shows the highest richness (178 species), consequence of the confluence of Atlantic and Mediterranean waters and of a greater depth range in this area (when comparing with the adjacent Alborán Sea sector). The total marine decapod species along Iberian waters (including crabs, Marco-Herrera et al., 2015) is, at least, 431. Also, other 13 freshwaters species have been cited in Iberian Peninsula.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
El dolor de espalda como lesión deportiva en jóvenes de 10-12 años
El objetivo de esta investigación es analizar la incidencia de dolor de espalda en jóvenes de entre 10 y 12 años en función de si practican o no algún deporte, cuál practican, con qué frecuencia, y las posibles diferencias entre género. El estudio se llevó a cabo en 2270 escolares (1214 niños y 1056 niñas) de 10-12 años de Mallorca. La muestra se obtuvo por conglomerados (centros escolares) por muestreo intencional. El cuestionario y la metodología de recogida de datos fueron previamente validados mediante el método test-retest. Los resultados obtenidos muestran que la existencia de dolor de espalda fue del 38.3% (34.5% en niños y 42.8% en niñas). Existe una relación significativa entre dolor de espalda y practicar deporte o no, en niños positiva y en niñas negativa, pudiendo ser explicado por las diferencias del tipo de deportes practicados según el género. Los mayores índices de incidencia de dolor de espalda aparecen entre los que practican voleibol, gimnasia deportiva y natación más de 4 horas semanales, y los que practican gimnasia rítmica. Este estudio sugiere, a partir de los resultados obtenidos, que el dolor de espalda es un mal que afecta de manera importante a la población juvenil, en especial al género femenino, y que el tipo de deporte practicado, así como su frecuencia, es determinante a la hora de definir si un deporte puede ser o no un factor de riesgo asociado al dolor de espalda.The aim of this research study is to explore the existence of back pain in schoolchildren aged 10-12 years old related to sports practice or not, sports type, frequency, and gender differences. This study was carried out using a sample of 2270 schoolchildren (1214 boys and 1056 girls) aged 10-12, resident in Mallorca. The sample was chosen using intentional random sampling. The questionnaire and method for gathering the data were previously validated using the test-rest reliability method. The results show the existence of low back pain among 38.3% of the schoolchildren (34.5% boys and 42.8% girls) suffers from back pain. There is a significant relationship between back pain and sport practice, positively in boys and negativity in girls, being explicated for the different sports practice according to gender. The highest values of back pain incidence were found in volleyball, masculine gymnastics and swimming more the 4 hours per week, and in rhythmic gymnastics. This study suggests, according to the results, back pain as a problem that affects the young population, especially to girls. The type of sport and its frequency is determinant to define if a sport could be or not a risk factor related to low back pain.O objectivo desta investigação foi analisar a incidência da dor cervical em jovens com idades compreendidas entre os 10 e os 12 anos em função de praticarem ou não algum desporto, qual praticam, com que frequência, e as possíveis diferenças de género. O estudo foi levado a cabo em 2270 alunos (1214 rapazes e 1056 raparigas) de 10-12 anos de Maiorca. A amostra foi composta por conglomerados (centros escolares) por amostragem de conveniência. O questionário e a metodologia de recolha de dados foram previamente validados mediante o método de teste-reteste. Os resultados obtidos mostram que a existência de dor cervical foi de 28.3% (34.5% em rapazes e 42.8% em raparigas). Existe uma relação significativa entre a dor cervical e praticar ou não desporto, positiva em rapazes e negativa em raparigas, podendo isto ser explicado pelas diferenças no tipo de modalidades praticadas segundo o género. Os maiores índices de incidência de dor cervical registam-se entre os que praticam voleibol, ginástica desportiva e natação mais de 4 horas semanais, e os que praticam ginástica rítmica. Este estudo sugere, a partir dos resultados obtidos, que a dor cervical é um mal que afecta de forma importante a população juvenil, em particular o género feminino, e que o tipo de modalidade praticada, assim como a sua frequência, é determinante quando se define se um desporto pode ou não ser um factor de risco associado à dor cervical
La dinámica de la población de las islas Baleares en el último tercio del siglo XIX (1878-1900)
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