10,267 research outputs found
Eggspection, organic egg verification tool
The institute for Food safety (RIKILT), part of Wageningen Univeristy and Research centre (Wageningen UR) has developed a method to verify the organic nature of eggs. The fingerprint of the natural caretonoids (carotenes and xanthophyllis) in eggs are used to discriminate between production systems. After extraction and processing the results are subsequently compared by statistical methods
Organic produce and production system conformity assessments : eggs and isotope analysis
Eggs were analysed for stable isotope composition, as a measure for organic produce authentication
Purity or pragmatism? : Reflecting on the use of systematic review methodology in development
Systematic review methodology pioneered in health care has been increasingly applied to development questions of importance in lower- and middle-income countries. This paper reports one such review on the topic of microfinance in sub-Saharan Africa and reflects on the number of pragmatic methodological compromises made when applying the method to a new field. These compromises relate to multidisciplinary teamwork, application of regional filters, drawing on evidence from additional study types and exploring mechanisms for change through the development and testing of a causal pathway. The paper concludes that a pragmatic rigorous approach to systematically reviewing evidence of effectiveness is needed for international development
B_K in Staggered Chiral Perturbation Theory
We calculate the kaon B-parameter, B_K, to next-to-leading order in staggered
chiral perturbation theory. We find expressions for partially quenched QCD with
three sea quarks, quenched QCD, and full QCD with m_u = m_d but not equal to
m_s. We extend the usual power counting to include the effects of using
perturbative (rather than non-perturbative) matching factors. Taste breaking
enters through the O(a^2) terms in the effective action, through O(a^2) terms
from the discretization of operators, and through the truncation of matching
factors. These effects cause mixing with several additional operators,
complicating the chiral and continuum extrapolations. In addition to the
staggered expressions, we present B_K at next-to-leading order in continuum
partially quenched chiral perturbation theory for N_f=3 sea quarks with m_u =
m_d but not equal to m_s.Comment: 56 pages, 3 figures (v3: Corrected normalization error in Eq.(4) and
subsequent equations; physics results unchanged. Version accepted to Phys.
Rev. D.
The influence of the noradrenergic system on optimal control of neural plasticity
Decision making under uncertainty is challenging for any autonomous agent. The challenge increases when the environment’s stochastic properties change over time, i.e., when the environment is volatile. In order to efficiently adapt to volatile environments, agents must primarily rely on recent outcomes to quickly change their decision strategies; in other words, they need to increase their knowledge plasticity. On the contrary, in stable environments, knowledge stability must be preferred to preserve useful information against noise. Here we propose that in mammalian brain, the locus coeruleus (LC) is one of the nuclei involved in volatility estimation and in the subsequent control of neural plasticity. During a reinforcement learning task, LC activation, measured by means of pupil diameter, coded both for environmental volatility and learning rate. We hypothesize that LC could be responsible, through norepinephrinic modulation, for adaptations to optimize decision making in volatile environments. We also suggest a computational model on the interaction between the anterior cingulate cortex (ACC) and LC for volatility estimation
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