Analysis of the neural hypercolumn in parallel PCSIM simulations

AbstractLarge and sudden changes in pitch or loudness occur statistically less frequently than gradual fluctuations, which means that natural sounds typically exhibit 1/f spectra. Experiments conducted on human subjects showed that listeners indeed prefer 1/f distributed melodies to melodies with faster or slower dynamics. It was recently demonstrated by using animal models, that neurons in primary auditory cortex of anesthetized ferrets exhibit a pronounced preference to stimuli that exhibit 1/f statistics. In the visual modality, it was shown that neurons in primary visual cortex of macaque monkeys exhibit tuning to sinusoidal gratings featuring 1/f dynamics.One might therefore suspect that neurons in mammalian cortex exhibit Self-Organizing Criticality. Indeed, we have found SOC-like phenomena in neurophysiological data collected in rat primary somatosensory cortex. In this paper we concentrated on investigation of the dynamics of cortical hypercolumn consisting of about 128 thousand simulated neurons. The set of 128 Liquid State Machines, each consisting 1024 neurons, was simulated on a simple cluster built of two double quad-core machines (16 cores).PCSIM was designed as a tool for simulating artificial biological-like neural networks composed of different models of neurons and different types of synapses. The simulator was written in C++ with a primary interface dedicated for the Python programming language. As its authors ensure it is intended to simulate networks containing up to millions of neurons and on the order of billions of synapses. This is achieved by distributing the network over different nodes of a computing cluster by using Message Passing Interface.The results obtained for Leaky Integrate-and-Fire model of neurons used for the construction of the hypercolumn and varying density of inter-column connections will be discussed. Benchmarking results for using the PCSIM on the cluster and predictions for grid computing will be presented to some extent. Research presented herein makes a good starting point for the simulations of very large parts of mammalian brain cortex and in some way leading to better understanding of the functionality of human brain

Influence of origin of the beans on protein quality and nutritive value of commercial soybean meals.

Chemical composition and correlations between chemical analyses and protein quality of 454 batches of SBM of 3 different origins (USA, n=168; Brazil (BRA), n=139, and Argentine (ARG), n=147) were studied. Samples were collected during a 6-yr period. SBM from USA had more CP, sucrose and stachyose and less NDF (P<0.001) than SBM from ARG and BRA. CP content was negatively related (P<0.001) with sucrose for USA meals and with NDF for ARG and BRA meals. Also, P content was positively related (P<0.01) with CP content of the meals. PDI and KOH solubility were higher (P<0.001) for USA than for ARG or BRA SBM, values that were positively related (P<0.001) with trypsin inhibitor activity of the meals. In addition, USA meals had more lys, met+cys, thr, and trp than BRA and ARG meals (P < 0.001). Per unit of CP, lys content was negatively related (P<0.001) with CP content for USA, positively for BRA, and no relations was found for ARG meals. It is concluded that nutritive values and protein quality of the meals varied widely among soybean origins. Consequently, the origin of the beans should be considered in the evaluation of the nutritive value of commercial SBM for non-ruminant animals

Type of grinding of the main cereal of the diet affects production of brown egg-laying hens

The influence of method of grinding of the cereal of the diet on production and egg quality was studied in 420 Hy-line brown egg-laying hens. The design was completely randomized with six treatments arranged as a 3 × 2 factorial with three cereals (barley, dented maize and soft wheat) and two grinding procedures (hammer mill vs. roller mill). Each treatment was replicated seven times and the experimental unit was an enriched cage with ten hens. Production was recorded every four weeks from 24 to 59 weeks of age and egg quality was measured at 40 and 56 weeks of age. For the entire experiment, feed intake was higher in hens fed wheat or maize than in hens fed barley (110.8 and 110.7 vs. 109.7 g/d; P = 0.014) but most of the differences were observed when the cereal was roller milled (P = 0.009 for the interaction). Also, egg production was similar for the three diets when the cereal was hammer milled but tended to be lower for the barley than for the wheat or maize diets when the cereal was roller milled (P = 0.09 for the interaction). None of the other productive or egg quality traits was affected by dietary treatment. We conclude that roller mills are useful to grind low fiber cereals, such as maize or wheat. However, the use of the roller mill might not be adequate when barley is the main cereal in diets for egg-laying hens

Diferencias en composición química y relaciones con la calidad de la proteína de las harinas de soja según origen.

La harina de soja (HS) es la principal fuente de proteína utilizada en la fabricación de piensos. En Europa, la mayor parte de las HS procede de uno de los tres principales países productores: Estados Unidos (USA), Brasil (BRA) y Argentina (ARG). La composición y valor nutricional de las HS varía entre países de origen en función de las variedades cultivadas, las condiciones agronómicas y las condiciones de procesado (Grieshop et al., 2003; De Coca et al., 2008, 2010; Frikha et al., 2012). En un trabajo anterior Mateos et al. (2011) presentaron los resultados obtenidos de una colección de 385 muestras de HS recogidas entre los años 2007 y 2010 procedentes de estos tres países. El presente trabajo tiene como objetivo complementar los resultados anteriores con nuevas muestras procedentes de las cosechas de los años 2011 y 2012. Asimismo se presentarán las correlaciones más destacadas entre componentes analíticos y las variables de calidad de la proteína habitualmente utilizadas por la industria

Influence of energy concentration and feed form of the diet on growth performance and digestive traits of brown egg-laying pullets from 1 to 120 days of age

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Efecto de la dl-metionina y la hidroxi-análoga de la dl-metionina sobre la productividad en pollos de engorde

La metionina (Met) es el aminoácido (AA) más limitante en dietas comerciales para avicultura. Durante los últimos 25 años, la DL-Met y la forma líquida del hidroxi análogo de la DL-Metionina ácido libre (MHA-FA) han sido las fuentes propuestas como suplementación en condiciones comerciales. Niveles excesivos de proteína bruta aumentan el coste y pueden perjudicar el desarrollo de las aves (Binder y Lemme, 2007). El objetivo de este ensayo fue evaluar los efectos de niveles crecientes de dos fuentes de Metionina sintética en pollos de engorde de 1 a 34 días de edad

The effect of a mono component protease and different AMEn levels in broiler diets on growth performance from 1 to 18 days of age.

The objective of the present study was to evaluate the effect of the inclusion of a mono component serine protease (RONOZYME ProAct, DSM Nutritional Products) in diets with two different AMEn contents on apparent ileal digestibility (AID) of amino acids (AA) and growth performance in broilers from 1 to 18 days of age

Influencia del origen del haba sobre el valor nutricional de la harina de soja

La harina de soja (HS) es la principal fuente de proteína en piensos para animales monogástricos. La mayor parte de las HS utilizadas en Europa proceden del continente Americano, en particular de Argentina (ARG), Brasil (BRA) y Estados Unidos (USA). Aunque la composición y valor nutricional de las HS varía entre países de origen (Grieshop et al., 2003; De Coca et al., 2008; 2010; Valencia et al., 2008), las tablas de composición de alimentos (NRC, 1998; FEDNA, 2010) clasifican las HS en función de su contenido en PB, sin tener en cuenta ni el origen ni las condiciones del procesado. En un trabajo anterior Mateos et al. (2009) se presentaron los resultados obtenidos de una colección de 262 muestras de HS recolectadas en las cosechas de los años 2007 y 2008 procedentes de estos tres países. Dependiendo de la variable considerada, el número de muestras analizadas varió entre 50 y 262. El presente trabajo tuvo como objetivo completar los análisis y complementar los resultados anteriores en relación con la composición química, el valor nutricional y la calidad de la PB de la HS con nuevas muestras procedentes de las cosechas de los años 2009 y 2010