Efficiency of Human Activity on Information Spreading on Twitter

Understanding the collective reaction to individual actions is key to effectively spread information in social media. In this work we define efficiency on Twitter, as the ratio between the emergent spreading process and the activity employed by the user. We characterize this property by means of a quantitative analysis of the structural and dynamical patterns emergent from human interactions, and show it to be universal across several Twitter conversations. We found that some influential users efficiently cause remarkable collective reactions by each message sent, while the majority of users must employ extremely larger efforts to reach similar effects. Next we propose a model that reproduces the retweet cascades occurring on Twitter to explain the emergent distribution of the user efficiency. The model shows that the dynamical patterns of the conversations are strongly conditioned by the topology of the underlying network. We conclude that the appearance of a small fraction of extremely efficient users results from the heterogeneity of the followers network and independently of the individual user behavior.Comment: 29 pages, 10 figure

Efficiency of Human Activity on Information Spreading on Twitter

Understanding the collective reaction to individual actions is key to effectively spread information in social media. In this work we define efficiency on Twitter, as the ratio between the emergent spreading process and the activity employed by the user. We characterize this property by means of a quantitative analysis of the structural and dynamical patterns emergent from human interactions, and show it to be universal across several Twitter conversations. We found that some influential users efficiently cause remarkable collective reactions by each message sent, while the majority of users must employ extremely larger efforts to reach similar effects. Next we propose a model that reproduces the retweet cascades occurring on Twitter to explain the emergent distribution of the user efficiency. The model shows that the dynamical patterns of the conversations are strongly conditioned by the topology of the underlying network. We conclude that the appearance of a small fraction of extremely efficient users results from the heterogeneity of the followers network and independently of the individual user behavior.Comment: 29 pages, 10 figure

Influence of match status on corner kick in elite soccer

El propósito del estudio es analizar como la variable situacional resultado parcial puede afectar al comportamiento táctico-estratégico en los saques de esquina en fútbol. Se han estudiado 902 saques de esquina realizados en 95 partidos correspondientes a la UEFA Euro 2012, y Fase Final de la FIFA World Cup 2010. Para identificar las interacciones se utilizó el método de crecimiento Chi-square automatic interaction detector (CHAID), que nos ha permitido identificar tres modelos: con el resultado de empate en los últimos minutos de juego, el equipo atacante incorpora al remate entre 2 a 5 jugadores y el equipo rival sitúa 1 ó 2 jugadores bajo palos. Ganando en los últimos minutos del encuentro, el equipo sitúa también entre 2 a 5 jugadores en ataque y el rival no defiende bajo palos. Perdiendo en los últimos minutos del encuentro, el equipo atacante incorpora a 6 o más jugadores al ataqueThe aim of this study was to examine the effects of the situational variable match status on corner kicks performance indicators in 95 matches played during the final stages of the 2012 UEFA European Championships and the 2010 FIFA World Cup. Video recordings of the matches were analyzed and coded post-event using notational analysis. Multiple interactions between the performance indicators and match status were analyzed using the Chi-squared automatic interaction detection (CHAID) decision-tree method. The results show that when a corner kick is taken during the last 30 minutes of the match, teams that are losing place 6 or more attackers in the shooting area, while teams that are drawing place 2-5 attackers in this area. In the same situation, teams that are drawing place 1-2 defenders at the goalposts while winning teams place non

A comparison of the prediction of apparent metabolisable energy content of starchy grains and cereal by-products for poultry from its chemical components, in vitro analysis or near-infrared reflectance spectroscopy

Regression models including chemical composition, in vitro digestibility and near infrared reflectance spectroscopy (NIRS) were compared in order to predict the energy value of several feed ingredients for poultry. The nitrogen-corrected apparent metabolisable energy content (AMEn) in cockerels and its proportion on total gross energy (AMEn/GE) were determined in 94 batches from six starchy grains and six cereal byproducts. Two preliminary trials were also designed to adapt in vitro methods for prediction of in vivo energy values for poultry. Mean concentrations of AMEn of the ingredient studied ranged from 2,464 to 3,595 kcal kg -1 DM, and those of AMEn/GE from 53.7 to 80.0%. The most precise model of prediction of AMEn and AMEn/GE values was that based on NIRS equations (R2 cv = 0.823 and 0.861, respectively). The best single chemical predictor of these energy values was the neutral detergent fibre concentration (R2 = 0.616 and 0.736, respectively). Further inclusion of ether extract and ash contents in the AMEn model and those of starch and ether extract in the AMEn/GE model allowed increasing coefficients of determination up to 0.791 and 0.839, respectively. A model including linear and quadratic effects of in vitro organic matter digestibility (IVOMd) provided a similar prediction of AMEn/GE values (R2 = 0.833). However the prediction of AMEn from IVOMd was worse (R2 = 0.62), as variations among batches of GE concentration (from 4,225 to 5,896 kcal kg –1 DM) were little related to in vitro digestibility values

Efecto de una restricción alimenticia después del destete sobre la mortalidad y los rendimientos productivos de conejos en cebo

En este trabajo se ha estudiado el efecto de una restricción alimenticia moderada 15 y gradual después del destete (alrededor de 35 d de edad) sobre los rendimientos 16 productivos y la eficiencia alimenticia global del cebo. La restricción consistió en 17 suministrar una cantidad limitada de alimento (80, 100 y 120 g/d) en las tres semanas 18 siguientes al destete. Se han realizado seis ensayos, con 480 animales cada uno, 19 utilizando seis piensos comerciales que diferían en el tipo de medicación. En estos 20 ensayos se controlaron los parámetros de crecimiento, eficacia alimenticia global y 21 mortalidad durante el periodo de restricción y en el conjunto del cebo (destete a 63-67 d 22 de edad). El número de ooquistes y de Clostridium perfringens en heces duras fue 23 también evaluado en cada tratamiento. En ninguno de los ensayos se detectaron 24 problemas de elevada mortalidad causada por ERE. En estas condiciones, la mortalidad 25 de los gazapos restringidos se redujo un 33% (P=0,02) en el periodo de restricción y 26 tendió a disminuir en el conjunto del periodo de cebo. Los resultados obtenidos 27 muestran además que una restricción alimenticia moderada mejora en un 4% (Pmenor que0,001) 28 la eficiencia alimenticia global del cebo, sin afectar al peso total de animales enviado a 29 matadero. Además, la adopción de medidas que disminuyan la proliferación de 30 coccidios y C. perfringens en el contenido digestivo pueden resultar útiles para reducir 31 la mortalidad de conejos durante el ceb

¿Qué deben saber los niños de educación primaria sobre la nutrición humana según los maestros en formación?

En este trabajo se pretende ofrecer una primera visión sobre los aspectos que los futuros maestros de Educación Primaria consideran esenciales que alcancen los alumnos al terminar esta etapa educativa con respecto a la nutrición humana. Concretamente nos centramos en los aspectos sobre la nutrición humana en general, los sistemas que intervienen en la nutrición y la repercusión en el medio de la obtención/eliminación de sustancias