28 research outputs found
Optimal Location of the U.S. Broiler Industry
Livestock Production/Industries, Marketing, Productivity Analysis,
Unlocking Community Capabilities Across Health Systems in Low- and Middle-Income Countries: Lessons Learned from Research and Reflective Practice
The right and responsibility of communities to participate
in health service delivery was enshrined in the 1978
Alma Ata declaration and continues to feature centrally
in health systems debates today. Communities are
a vital part of people-centred health systems and
their engagement is critical to realizing the diverse
health targets prioritised by the Sustainable Development
Goals and the commitments made to Universal
Health Coverage. Community members' intimate
knowledge of local needs and adaptive capacities are essential
in constructively harnessing global transformations
related to epidemiological and demographic transitions,
urbanization, migration, technological innovation and
climate change. Effective community partnerships and
governance processes that underpin community capability
also strengthen local resilience, enabling communities to
better manage shocks, sustain gains, and advocate for
their needs through linkages to authorities and services.
This is particularly important given how power relations
mark broader contexts of resource scarcity and concentration,
struggles related to social liberties and other types of
ongoing conflicts.IS
Optogenetic Mimicry of the Transient Activation of Dopamine Neurons by Natural Reward Is Sufficient for Operant Reinforcement
Activation of dopamine receptors in forebrain regions, for minutes or longer, is known to be sufficient for positive reinforcement of stimuli and actions. However, the firing rate of dopamine neurons is increased for only about 200 milliseconds following natural reward events that are better than expected, a response which has been described as a “reward prediction error” (RPE). Although RPE drives reinforcement learning (RL) in computational models, it has not been possible to directly test whether the transient dopamine signal actually drives RL. Here we have performed optical stimulation of genetically targeted ventral tegmental area (VTA) dopamine neurons expressing Channelrhodopsin-2 (ChR2) in mice. We mimicked the transient activation of dopamine neurons that occurs in response to natural reward by applying a light pulse of 200 ms in VTA. When a single light pulse followed each self-initiated nose poke, it was sufficient in itself to cause operant reinforcement. Furthermore, when optical stimulation was delivered in separate sessions according to a predetermined pattern, it increased locomotion and contralateral rotations, behaviors that are known to result from activation of dopamine neurons. All three of the optically induced operant and locomotor behaviors were tightly correlated with the number of VTA dopamine neurons that expressed ChR2, providing additional evidence that the behavioral responses were caused by activation of dopamine neurons. These results provide strong evidence that the transient activation of dopamine neurons provides a functional reward signal that drives learning, in support of RL theories of dopamine function
REGIONAL SURPLUS AND DEFICIT ESTIMATES FOR BROILERS, TURKEYS, AND EGGS, 1975-84
Population growth patterns and shifts in poultry production during the past 10 years caused major changes in the regional supply-consumption balances for poultry products. The South continues increasing its share of both broilers and turkeys. However, the southward movement of egg production peaked in 1979-80 and has now reversed itself, with rapid expansion in the East North Central region. More broiler and turkey meat but fewer eggs are being shipped between regions