1,547 research outputs found
How Changes in Plant Community Structure Affect Ant Communities
We investigated how change in plant community composition and vegetative structure brought about by annual grass-specific herbicide application affects terrestrial arthropod communities, with special emphasis on the potential of the endangered Fender’s blue butterfly, Plebejus icarioides fenderi (Family: Lycaenidae). Larvae of this species form facultative protective mutualisms with ants, who chase away potential predators of the larvae. We used pitfall trapping to compare ant community structure between control and herbicide-treated plots through time. The extent to which major changes in plant community composition affect the mutualistic ant community may have relevance for management decisions if the focus of the conservation effort has strong ecological interactions with greatly affected non-target species
Pathological Speech Classification Using a Convolutional Neural Network
Convolutional Neural Networks (CNNs) have enabled significant improvements across a number of applications in computer vision such as object detection, face recognition and image classification. An audio signal can be visually represented as a spectrogram that captures the time-varying frequency content of the signal. This paper describes how a CNN can be applied to the spectrogram of an audio signal to distinguish pathological from healthy speech. We propose a CNN structure and implement it using Keras to test the approach. A classification accuracy of over 95% is obtained in experiments on two public pathological speech datasets
Economic structural transformation and equity in Vietnam: Lessons from Post-War Japan
Duality in economic structure is an enduring characteristic of many developing and emerging economies, and even when economies industrialize, structural and regional imbalance remains a challenging problem in economic development. Japan however managed to solve the problem of duality in its economic structure in the post-war period. This research analyses the Japanese economic transformation experience and draws lessons for Vietnam, which even though has made great strides in reducing poverty, still faces the challenge of economic structural duality and regional imbalance characterized by poverty. The main finding is that raising productivity uniformly across sectors and regions was central to Japanese structural economic transformation, and that such productivity rise can be facilitated by uniform infrastructure development and judicious governmental policies directly impacting the right combinations of factors of production, namely increase in capital and technology in all productive sectors. The lessons drawn for Vietnam are judicious governmental policies providing incentives for increasing technology and capital investments even in rural areas. In addition, governmental policies positively impacting agricultural commodity prices, infrastructure development, and land reforms are recommended for Vietnam. Keywords: Economic Duality, Economic Structural Transformation, Equity, Japanese and Vietnamese Economic Developmen
Influence of atmospheric electric fields on radio emission from air showers
We show that atmospheric electric fields as exist in thunderclouds can strongly affect the radio
emission from cosmic air showers. We also show, using data from LOFAR, that from the measured
radio footprint of cosmic-ray air showers, i.e. intensity, linear and circular polarization at
various distances from the shower core, one can determine the direction and strength of the electric
field as function of height along the path of the cosmic ray. This method can be regarded as
tomography of thundercloud electric fields using cosmic rays as probes. We will present an analysis
of selected events measured during thunderstorm conditions in the period from December
2011 till August 2014. The fields we extract are consistent with the generally accepted charge
structure in thunderclouds consisting out of three charge layers
selective dissolution of woody biomass under hydrothermal conditions
Abstract This study analyzes semi-continuous hydrothermal hydrolysis of lignocellulosic biomass operating between 200°C and 300°C with constant inlet water flow rate. Experiments were executed in a novel reactor system that offered a nearly linear temperature behavior during the heating period with heating rates between 40°C/min and 60 °C/min and a nearly flat temperature profile during retention. Experimental results suggest that conversion efficiency improved at higher temperatures. After completion of the batch, solid and liquid products were collected and mass balance closures reached an average of 89%. It was discovered that, regardless of the temperature, a minimum of 90% of the total dissolution occurs within the first 15 minutes of the reaction. This work identifies various stages and conditions that favor the dissolution of certain components (hemicellulose, cellulose or lignin)
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