3,650 research outputs found
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
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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
Wave Attenuation by Spartina Saltmarshes in the Chesapeake Bay Under Storm Surge Conditions
This material is based upon work supported by the National Fish and Wildlife Foundation and the U.S. Department of the Interior under grant 43932.This material is also based upon work supported by the National Science Foundation under grant SES‐1331399.This research was also supported in part by the Thomas F. and Kate Miller Jeffress Memorial Trust, Bank of America, Trustee. M. Maza, J.L. Lara, and I.J. Losada are indebted to the Spanish Ministry of Economy and Competitiveness for the funding provided in the RETOS INVESTIGACION 2014 (grant BIA2014‐59718‐R) grant program
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