231 research outputs found

    THE FUTURE OF RICE PRODUCTION AND CONSUMPTION

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    Rice is the fundamental principal food for about half of the world'Â’s population, and it supplies 20% of the calories consumed worldwide. Rice consumption increases with population. In the 21st century, a large increase in population is anticipated. Most of the increase will occur in Asia and Africa, where the population lives on rice. The food problem will become as important as the environmental problem. We present basic data for thinking about the food problem in the future. In this research, we consider Asia, Africa, Europe, the Americas and Oceania as model areas and examine rice production and consumption in each area. We study rice-deficit areas, rice-surplus areas, and their total balance.Crop Production/Industries,

    A Continental Method for Estimating the Supply and Import/ Export of Wheat

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    Wheat is the principal food of about half of the world’s population. In the 21st century, a steep increase in the global population is expected, mostly in Asia and Africa. While there is a saturation of food in developed countries, many developing countries suffer from a food shortage. We examine the production and supply of wheat by continent, focusing mainly on wheat shortages in Asia and Africa. We also drew conclusions about wheat distribution.International Relations/Trade,

    The Future of Rice Production, Consumption and Seaborne Trade: Synthetic Prediction Method

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    Crop Production/Industries, Food Consumption/Nutrition/Food Safety, International Relations/Trade,

    Neuromagnetic Activation of Primaryand Secondary Somatosensory Cortex Following Tactile-on and Tactile-off Stimulation

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    Objective Magnetoencephalography (MEG) recordings were performed to investigate the cortical activation following tactile-on and tactile-off stimulation. Methods We used a 306-ch whole-head MEG system and a tactile stimulator driven by a piezoelectric actuator. Tactile stimuli were applied to the tip of right index finger. The interstimulus interval was set at 2000 ms, which included a constant stimulus of 1000 ms duration. Results Prominent somatosensory evoked magnetic fields were recorded from the contralateral hemisphere at 57.5 ms and 133.0 ms after the onset of tactile-on stimulation and at 58.2 ms and 138.5 ms after the onset of tactile-off stimulation. All corresponding equivalent current dipoles (ECDs) were located in the primary somatosensory cortex (SI). Moreover, long-latency responses (168.7 ms after tactile-on stimulation, 169.8 ms after tactile-off stimulation) were detected from the ipsilateral hemisphere. The ECDs of these signals were identified in the secondary somatosensory cortex (SII). Conclusions The somatosensory evoked magnetic fields waveforms elicited by the two tactile stimuli (tactile-on and tactile-off stimuli) with a mechanical stimulator were strikingly similar. These mechanical stimuli elicited both contralateral SI and ipsilateral SII activities. Significance Tactile stimulation with a mechanical stimulator provides new possibilities for experimental designs in studies of the human mechanoreceptor system

    Gait parameter adjustments for walking on a treadmill at preferred, slower, and faster speeds in older adults with down syndrome,”

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    The combined effects of ligamentous laxity, hypotonia, and decrements associated with aging lead to stability-enhancing foot placement adaptations during routine overground walking at a younger age in adults with Down syndrome (DS) compared to their peers with typical development (TD). Our purpose here was to examine real-time adaptations in older adults with DS by testing their responses to walking on a treadmill at their preferred speed and at speeds slower and faster than preferred. We found that older adults with DS were able to adapt their gait to slower and faster than preferred treadmill speeds; however, they maintained their stability-enhancing foot placements at all speeds compared to their peers with TD. All adults adapted their gait patterns similarly in response to faster and slower than preferred treadmill-walking speeds. They increased stride frequency and stride length, maintained step width, and decreased percent stance as treadmill speed increased. Older adults with DS, however, adjusted their stride frequencies significantly less than their peers with TD. Our results show that older adults with DS have the capacity to adapt their gait parameters in response to different walking speeds while also supporting the need for intervention to increase gait stability

    Gait Parameter Adjustments for Walking on a Treadmill at Preferred, Slower, and Faster Speeds in Older Adults with Down Syndrome

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    The combined effects of ligamentous laxity, hypotonia, and decrements associated with aging lead to stability-enhancing foot placement adaptations during routine overground walking at a younger age in adults with Down syndrome (DS) compared to their peers with typical development (TD). Our purpose here was to examine real-time adaptations in older adults with DS by testing their responses to walking on a treadmill at their preferred speed and at speeds slower and faster than preferred. We found that older adults with DS were able to adapt their gait to slower and faster than preferred treadmill speeds; however, they maintained their stability-enhancing foot placements at all speeds compared to their peers with TD. All adults adapted their gait patterns similarly in response to faster and slower than preferred treadmill-walking speeds. They increased stride frequency and stride length, maintained step width, and decreased percent stance as treadmill speed increased. Older adults with DS, however, adjusted their stride frequencies significantly less than their peers with TD. Our results show that older adults with DS have the capacity to adapt their gait parameters in response to different walking speeds while also supporting the need for intervention to increase gait stability

    Biomechanical mechanism for transitions in phase and frequency of arm and leg swing during walking

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    As humans increase walking speed, there are concurrent transitions in the frequency ratio between arm and leg movements from 2:1 to 1:1 and in the phase relationship between the movements of the two arms from in-phase to out-of-phase. Superharmonic resonance of a pendulum with monofrequency excitation had been proposed as a potential model for this phenomenon. In this study, an alternative model of paired pendulums with multiple-frequency excitations is explored. It was predicted that the occurrence of the concurrent transitions was a function of (1) changes in the magnitude ratio of shoulder accelerations at step and stride frequencies that accompany changes in walking speed and (2) proximity of these frequencies to the natural resonance frequencies of the arms modeled as a pair of passive pendulums. Model predictions were compared with data collected from 14 healthy young subjects who were instructed to walk on a treadmill. Walking speeds were manipulated between 0.18 and 1.52 m/s in steps of 0.22 m/s. Kinematic data for the arms and shoulders were collected using a 3D motion analysis system, and simulations were conducted in which the movements of a double-pendulum system excited by the accelerations at the suspension point were analyzed to determine the extent to which the arms acted as passive pendulums. It was confirmed that the acceleration waveforms at the shoulder are composed primarily of stride and step frequency components. Between the shoulders, the stride frequency components were out-of-phase, while the step frequency components were in-phase. The amplitude ratio of the acceleration waveform components at the step and stride frequencies changed as a function of walking speed and were associated with the occurrence of the transitions. Simulation results using these summed components as excitatory inputs to the double-pendulum system were in agreement with actual transitions in 80% of the cases. The potential role of state-dependent active muscle contraction at shoulder joints on the occurrence of the transitions was discussed. Due to the tendency of arm movements to stay in the vicinity of their primary resonance frequency, these active muscle forces were hypothesized to function as escapements that created limit cycle oscillations at the shoulder’s resonant frequency.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47437/1/422_2004_Article_503.pd
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