Modulation formats for multi-core fiber transmission.

We investigate high dimensional modulation formats for multi-core fibers (MCFs) and spatial superchannels. We show that the low skew variations between MCF cores maybe exploited to generate 'multi-core' formats that offer significant advantages over independently transmitting conventional 4-dimensional formats in each core. We describe how pulse position modulation formats may be transposed to the spatial domain and then investigate a family of modulation formats referred to as core-coding, one of which has the same power and spectral efficiency as polarization switched quaternary phase shift keying but with half of the optical power, potentially improving non-linear tolerance for long distance transmission, albeit at the cost of implementation challenges. Finally, we investigate the application of set-partitioning to multi-core formats using a single-parity check bit transmitted in one quadrature of one polarization in one of the cores and polarization-division multiplexing quadrature phase shift keying data in all remaining cores. We observe that for high core counts, an advantage of almost 3 dB in asymptotic power efficiency may be obtained with negligible impact on spectral efficiency, which translates into experimentally measured reduction in the required optical signal-to-noise ratio of up to 1.8 dB at a bit-error-rate of 10-5 and the same data-rate, and additional transmission reach of up to 20%.

[Some epidemiological aspects of myasthenia gravis in Cuba]. / Algunos aspectos epidemiológicos de la miastenia gravis en Cuba.

We estimated the rates of prevalence, incidence, mortality and lethality for myasthenia gravis in Cuba based upon previous epidemiological studies carried out in eight of Cuba's fourteen provinces: Pinar del Río, Havana City, Havana, Matanzas, Cienfuegos, Sancti Spíritus, Camagüey and Guantánamo. Rates of incidence, prevalence and mortality were 4.52, 29.22 and 0.72 per million inhabitants respectively. Lethality rate was 10.77%.

Algunos aspectos epidemiológicos de la miastenia gravis en Cuba / Some epidemiological aspects of Myasthenia Gravis in Cuba incidence mortality and lehality for myastenia gravis in Cuba

Se estimaron las tasas de incidencia, prevalencia, mortalidad y letalidad pormiastenia gravis en Cuba, previo estudios epidemiológicos desarrollados en 8 de las 14 provincias del país: Pinar del Río, Ciudad de La Habana, La Habana, Matanzas, Cienfuegos, Sancti-Spíritus, Camaguey y Guantánamo. Las tasas de incidencia, prevalencia y mortalidad dieron de 4,52, 29,22 y 0,72 por millón de habitantes respectivamente. La tasa de letalidad fue de 10,77