K-contact Lie groups of dimension five or greater

We prove that a K-contact Lie group of dimension five or greater is the central extension of a symplectic Lie group by complexifying the Lie algebra and applying a result from complex contact geometry, namely, that, if the adjoint action of the complex Reeb vector field on a complex contact Lie algebra is diagonalizable, then it is trivial

Mathematical algorithms to maximize performance in numerical weather prediction

Numerical weather prediction models, which involve the solution of non-linear partial differential equations at points on an extensive three dimensional grid, are ideally suited for processing on vector machines. It was logical therefore that the new global forecast model to be implemented at the Meteorological Office should be written in vector code for the CYBER 205. In order to achieve full efficiency and to reduce storage requirements the model used 32-bit arithmetic which was found to provide high enough precision. Unfortunately, however, the trigonometrical and logarithmic functions provided by CDC could only handle 64-bit vectors and, although written in efficient scalar code, did not take advantage of the special facilities of a vector processor. It was therefore necessary to rewrite the functions in vector code to handle both 32 and 64-bit vectors. There was also no half-precision compiler available for the Cyber 205 at that time and so the functions, like the model, had to make extensive use of the special call syntax. This made the code more difficult to write but it allowed much greater flexibility in that it became possible to access the exponent of a floating-point number independently of its coefficient. A description is given of the technique and the results which were achieved are summarized

A Model of Later Nineteenth Century European Economic Development

Editada en la Fundación Empresa PúblicaEn este trabajo se desarrolla y estima un modelo para explicar los motivos por los cuales algunos países europeos prosperaron más rápidamente que otros en el período 1860- 1910. El modelo cuantifica por dos vías distintas los factores que contribuyeron a las diferencias de ingreso entre España y Gran Bretaña. Los determinantes que se consideran más significativos son los recursos naturales, la política económica y la herencia cultural reflejada en los niveles educativos.A model is developed and estimated to explain why some European countries were richer than others between 1860 and 1910 and why some increased their prosperity faster in the period. The model quantifies by two methods some of the contributors to the income gap between the economies of Spain and Britain in 1880 and 1910. Determinants of European nations' output per head included natural endowments (climate and coal deposits), economic policy (tariff protection and very marginally the gold standard), and cultural heritage as reflected in literacy. Measurement errors, country specific factors and perhaps variables not considered in this analysis account for less than half Spanish-UK income differences at the dates estimated.Publicad

The relationship between otolith increments and time for yellowfin and skipjack tuna marked with tetracycline

ENGLISH: The rate at which increments are deposited on the sagittal otoliths of yellowfin (Thunnus albacares) and skipjack (Katsuwonus p elamis) tunas is determined by a markrecapture experiment using tetracycline. During growth in fork length from 40 to 110 em, and for a period of up to 389 days, yellowfin of the Revillagigedo Islands- Baja California region deposit one increment per day in either the postrostrum or rostrum position of the otolith. For skipjack of the same region, rostrum increments underestimate time by approximately 24 percent during growth from 42 to 64 cm and over the maximum interval of 249 days. The growth rate of each species is estimated from the recapture fork length and the linear change in an otolith dimension following tetracycline injection. Over specific ranges in fork length the rates are 3.06 and 1.15 em per month for yellowfin and skipjack, respectively. SPANISH: La rapidez (tasa) en la que se depositan los incrementos en los otolitos sagitales del aleta amarilla (Thunnus albacares) y el barrilete (Katsuwonus pelamis) se determina mediante un experimento al recapturar los peces que han sido marcados con tetraciclina. Durante el crecimiento de la longitud de horquilla de 40 a 110 cm y por un período hasta de 389 días, se forma en el aleta amarilla de la región de las Islas Revillagigedo-Baja California, un incremento diario ya sea en el parte del postrostrum o rostrum de los otolitos. Con respecto al barrilete de la misma region los incrementos en el rostrum subestiman aproximadamente el tiempo en un 24 por ciento durante el crecimiento de 42 a 64 cm y sobre un intervalo máximo de 249 días. El índice de crecimiento de cada especie se estima en la recaptura según la longitud de horquilla y el cambio lineal en la dimensión de un otolito después de la inyección de tetraciclina. La variación específica sobre la longitud de horquilla de los índices son 3.06 y 1.15 cm por mes para el aleta amarilla y el barrilete, respectivamente. (PDF contains 54 pages.

Mammalian gene expression variability is explained by underlying cell state.

Gene expression variability in mammalian systems plays an important role in physiological and pathophysiological conditions. This variability can come from differential regulation related to cell state (extrinsic) and allele-specific transcriptional bursting (intrinsic). Yet, the relative contribution of these two distinct sources is unknown. Here, we exploit the qualitative difference in the patterns of covariance between these two sources to quantify their relative contributions to expression variance in mammalian cells. Using multiplexed error robust RNA fluorescent in situ hybridization (MERFISH), we measured the multivariate gene expression distribution of 150 genes related to Ca2+ signaling coupled with the dynamic Ca2+ response of live cells to ATP. We show that after controlling for cellular phenotypic states such as size, cell cycle stage, and Ca2+ response to ATP, the remaining variability is effectively at the Poisson limit for most genes. These findings demonstrate that the majority of expression variability results from cell state differences and that the contribution of transcriptional bursting is relatively minimal