Prediction of enzyme kinetic parameters based on statistical learning

Values of enzyme kinetic parameters are a key requisite for the kinetic modelling of biochemical systems. For most kinetic parameters, however, not even an order of magnitude is known, so the estimation of model parameters from experimental data remains a major task in systems biology. We propose a statistical approach to infer values for kinetic parameters across species and enzymes making use of parameter values that have been measured under various conditions and that are nowadays stored in databases. We fit the data by a statistical regression model in which the substrate, the combination enzyme-substrate and the combination organism-substrate have a linear effect on the logarithmic parameter value. As a result, we obtain predictions and error ranges for unknown enzyme parameters. We apply our method to decadic logarithmic Michaelis-Menten constants from the BRENDA database and confirm the results with leave-one-out crossvalidation, in which we mask one value at a time and predict it from the remaining data. For a set of 8 metabolites we obtain a standard prediction error of 1.01 for the deviation of the predicted values from the true values, while the standard deviation of the experimental values is 1.16. The method is applicable to other types of kinetic parameters for which many experimental data are available

Hunger in America 2014: National Report

Feeding America, the nation's leading domestic hunger-relief organization, has conducted the most comprehensive study of hunger in America every four years since 1993. Like the prior studies, Hunger in America 2014 (HIA 2014), the latest iteration, documents the critical role that the charitable food assistance network plays in supporting struggling families in the United States. Study results are based on surveys of food programs in the charitable food assistance network supported by Feeding America, and clients that access services through that network in 2012-2013. In addition to this report on the Feeding America national network, this study has resulted in 42 state reports and 196 food bank reports detailing network activities on local levels.The current assessment occurs in a period with historically high demand for food assistance. Unemployment and poverty rates have remained high since the Great Recession of 2008, and the number of households receiving nutrition assistance from the federal government's Supplemental Nutrition Assistance Program has increased by approximately 50 percent between 2009 and 2013.Demand for charitable food assistance has also expanded. HIA 2014 finds an increased number of individuals relying on charitable assistance to access nutritious foods for themselves and their families

Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment

The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu Photonics K.K. (HPK) is used in various experiments in particle and astroparticle physics. We describe the test and calibration of 474 PMTs for the reactor antineutrino experiment Double Chooz. The unique test setup at Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate 30 PMTs simultaneously and to characterize the single photo electron response, transit time spread, linear behaviour and saturation effects, photon detection efficiency and high voltage calibration

Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment

The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu Photonics K.K. (HPK) is used in various experiments in particle and astroparticle physics. We describe the test and calibration of 474 PMTs for the reactor antineutrino experiment Double Chooz. The unique test setup at Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate 30 PMTs simultaneously and to characterize the single photo electron response, transit time spread, linear behaviour and saturation effects, photon detection efficiency and high voltage calibration

Qualification Tests of 474 Photomultiplier Tubes for the Inner Detector of the Double Chooz Experiment

The hemispherical 10" photomultiplier tube (PMT) R7081 from Hamamatsu Photonics K.K. (HPK) is used in various experiments in particle and astroparticle physics. We describe the test and calibration of 474 PMTs for the reactor antineutrino experiment Double Chooz. The unique test setup at Max-Planck-Institut f\"ur Kernphysik Heidelberg (MPIK) allows one to calibrate 30 PMTs simultaneously and to characterize the single photo electron response, transit time spread, linear behaviour and saturation effects, photon detection efficiency and high voltage calibration

Rainfall is associated with social behaviour in Seychelles warblers

Species are facing environmental challenges caused by rapidly changing environments induced by climate change. In tropical regions, climate change causes increasing frequencies of extreme weather,like droughts or extreme rainfall. Natural selection is usually slow and adaptations through phenotypic plasticity are limited, thus species might need more mechanisms to cope with change, like cooperative breeding. Rainfall is an important cue for onset of breeding in many tropical bird species, so young are born when food abundance is highest. We explore the effect of rainfall on the social behaviour and life history of the insectivorous Seychelles warblers (Acrocephalus sechellensis), a facultative cooperative58breeder, using long-term data. We expect that with increasing amounts of rain food resources will increase, and thus reproductive output and survival will increase. If so, in dry periods, reproductive output of breeding pairs will be limited, but cooperative breeding may counteract this negative effect because helpers assist with feeding young. We expect that in dry periods breeding pairs produce more offspring of the helping sex, who stay in their natal territory and become helpers in the following year. Rainfall positively affected insect abundance. With increasing rainfall, survival of individuals during the breeding season and reproductive output, especially for cooperatively breeding groups, increased. With more rainfall, also more daughters (the helping sex) were produced, resulting in more group formation the year after. Thus, in contrast to our expectations, Seychelles warblers form social groups in favourable conditions, indicating that group living may be costly and thus not a solution to coping with changing environments. This study showed that the interaction between the environment and life histories,including social behaviour, is complex, and important to consider when studying the impact of changing environments on species surviva

Rainfall is associated with social behaviour in Seychelles warblers

Species are facing environmental challenges caused by rapidly changing environments induced by climate change. In tropical regions, climate change causes increasing frequencies of extreme weather,like droughts or extreme rainfall. Natural selection is usually slow and adaptations through phenotypic plasticity are limited, thus species might need more mechanisms to cope with change, like cooperative breeding. Rainfall is an important cue for onset of breeding in many tropical bird species, so young are born when food abundance is highest. We explore the effect of rainfall on the social behaviour and life history of the insectivorous Seychelles warblers (Acrocephalus sechellensis), a facultative cooperative58breeder, using long-term data. We expect that with increasing amounts of rain food resources will increase, and thus reproductive output and survival will increase. If so, in dry periods, reproductive output of breeding pairs will be limited, but cooperative breeding may counteract this negative effect because helpers assist with feeding young. We expect that in dry periods breeding pairs produce more offspring of the helping sex, who stay in their natal territory and become helpers in the following year. Rainfall positively affected insect abundance. With increasing rainfall, survival of individuals during the breeding season and reproductive output, especially for cooperatively breeding groups, increased. With more rainfall, also more daughters (the helping sex) were produced, resulting in more group formation the year after. Thus, in contrast to our expectations, Seychelles warblers form social groups in favourable conditions, indicating that group living may be costly and thus not a solution to coping with changing environments. This study showed that the interaction between the environment and life histories,including social behaviour, is complex, and important to consider when studying the impact of changing environments on species surviva