Energy and environmental burdens of organic and non-organic agriculture and horticulture

Production of 10 major commodities in England and Wales was studied using Life Cycle Analysis (LCA). Organic and non-organic (contemporary conventional) systems were compared. Organic production was generally less energy consuming, except for poultry meat, eggs and tomatoes. Environmental burdens, such as global warming potential or eutrophication were often greater per unit of production from organic than non-organic systems

Teaching and learning evidence-based medicine: cross-sectional survey investigating knowledge and attitudes of teachers and learners in primary and secondary care

Evidence-based medicine (EBM) is an important component of quality healthcare and a key part of the curriculum for doctors in training. There have been no previous studies comparing attitudes and knowledge of doctors in primary and secondary care towards EBM practice and teaching and this study sets out to investigate this area. We asked participants, a stratified sample of general practitioners, hospital consultants, GP registrars and junior hospital doctors in Leicester, Northamptonshire and Rutland, UK, to complete a self-administered survey questionnaire and written knowledge test which provided ‘positive to evidence based practice’ (PEP) attitude scores and Manchester Short EBM Questionnaire Education for Primary Care (2007) 18: 45–57 # 2007 Radcliffe Publishing Limited WHAT IS ALREADY KNOWN IN THIS AREA. There is little evidence on the relationship between attitudes and knowledge in relation to evidence-based medicine (EBM) in family doctors, consultants and doctors intraining. WHAT THIS WORK ADDS. This study showed that, although general practitioners and general practitioner trainers were significantly less positive in attitude to EBM compared to GP registrars, junior hospital doctors and consultant respondents, they had significantly higher knowledge scores. This study demonstrated that the attitude (PEP) score and knowledge questionnaire(MANSEBMQ) have high reliability but require further research to demonstrate validity. SUGGESTIONS FOR FURTHER RESEARCH. There remain opportunities for refinement of the MANSEBMQ, validation against existing tools and further application in a larger study, including assessment of EBM knowledge and skills, before and after an educational process, involving students in clinically relevant and integrated EBM learning. Keywords: attitudes, evidence-based practice, general practice registrars, general practitioners, hospital doctors, primary care, secondary care(MANSEBMQ) knowledge scores of participants. The response rate was low which may have led to volunteer bias but there were sufficient responses to explore attitude scores and knowledge scores. Attitude(PEP) scores were highest in hospital consultants, intermediate in doctors in training and lowest in general practitioner (GP)respondents (mean score 71.7 vs 70.5 vs 67.2; P = 0.006). PEP scores were also highest in respondents with higher degrees (MD, PhD, MSc), intermediate in those with higher professional qualifications (MRCP, FRCS, MRCGP or equivalent) and lowest in those with none of these (mean score 72.9 vs 70.6 vs 67.2; P = 0.005). PEP scores were significantly higher(P = 0.002) in respondents who taught EBM (mean score 71.7, 95% CI 70.3 to 73.2, n=109, missing=5) compared with those who did not (mean score 68.6, 95% CI 67.3 to 69.9, n = 105, missing = 12) and in respondents with research experience (P < 0.001), research training (P < 0.001) and training in EBM (P = 0.001). There was a positive correlation between PEP score and MANSEBMQ score (P = 0.013). In contrast, and paradoxically opposite to the pattern of attitudes, knowledge scores were highest in GPs, intermediate in junior hospital doctors and lowest in consultant respondents (mean score 63.5 vs 61.9 vs 54.5, P=0.005). Although GPs and GP trainers were significantly less positive in attitude to EBM compared to GP registrars, junior hospital doctors and consultant respondents, they had significantly higher knowledge scores. This study demonstrated that the attitude(PEP) score and knowledge questionnaire (MANSEBMQ) have good reliability but require further research to demonstrate validity

Chirality Selection in Open Flow Systems and in Polymerization

As an attempt to understand the homochirality of organic molecules in life, a chemical reaction model is proposed where the production of chiral monomers from achiral substrate is catalyzed by the polymers of the same enatiomeric type. This system has to be open because in a closed system the enhanced production of chiral monomers by enzymes is compensated by the associated enhancement in back reaction, and the chiral symmetry is conserved. Open flow without cross inhibition is shown to lead to the chirality selection in a general model. In polymerization, the influx of substrate from the ambience and the efflux of chiral products for purposes other than the catalyst production make the system necessarily open. The chiral symmetry is found to be broken if the influx of substrate lies within a finite interval. As the efficiency of the enzyme increases, the maximum value of the enantiomeric excess approaches unity so that the chirality selection becomes complete.Comment: 8 pages, 4 figure

Enhancement factor for the electron electric dipole moment in francium and gold atoms

If electrons had an electric dipole moment (EDM) they would induce EDMs of atoms. The ratio of the atomic EDM to the electron EDM for a particular atom is called the enhancement factor, R. We calculate the enhancement factor for the francium and gold atoms, with the results 910 plus/minus 5% for Fr and 260 plus/minus 15% for Au. The large values of these enhancement factors make these atoms attractive for electron EDM measurements, and hence the search for time-reversal invariance violation.Comment: 6 pages, no figures, uses RevTex, reference adde

Measurement of the electron's electric dipole moment using YbF molecules: methods and data analysis

We recently reported a new measurement of the electron's electric dipole moment using YbF molecules [Nature 473, 493 (2011)]. Here, we give a more detailed description of the methods used to make this measurement, along with a fuller analysis of the data. We show how our methods isolate the electric dipole moment from imperfections in the experiment that might mimic it. We describe the systematic errors that we discovered, and the small corrections that we made to account for these. By making a set of additional measurements with greatly exaggerated experimental imperfections, we find upper bounds on possible uncorrected systematic errors which we use to determine the systematic uncertainty in the measurement. We also calculate the size of some systematic effects that have been important in previous electric dipole moment measurements, such as the motional magnetic field effect and the geometric phase, and show them to be negligibly small in the present experiment. Our result is consistent with an electric dipole moment of zero, so we provide upper bounds to its size at various confidence levels. Finally, we review the prospects for future improvements in the precision of the experiment.Comment: 35 pages, 15 figure

Nucleon Edm from Atomic Systems and Constraints on Supersymmetry Parameters

The nucleon EDM is shown to be directly related to the EDM of atomic systems. From the observed EDM values of the atomic Hg system, the neutron EDM can be extracted, which gives a very stringent constraint on the supersymmetry parameters. It is also shown that the measurement of Nitrogen and Thallium atomic systems should provide important information on the flavor dependence of the quark EDM. We perform numerical analyses on the EDM of neutron, proton and electron in the minimal supersymmetric standard model with CP-violating phases. We demonstrate that the new limit on the neutron EDM extracted from atomic systems excludes a wide parameter region of supersymmetry breaking masses above 1 TeV, while the old limit excludes only a small mass region below 1 TeV.Comment: 10 pages, 7 figure file

Atomic Parity Violation and Precision Electroweak Physics - An Updated Analysis

A new analysis of parity violation in atomic cesium has led to the improved value of the weak charge, $Q_W({\rm Cs}) = -72.06 \pm 0.46$. The implications of this result for constraining the Peskin-Takeuchi parameters S and T and for guiding searches for new Z bosons are discussed.Comment: 8 pages, LaTeX, 3 figures, Submitted to Physical Review D. Updated experimental inputs and references; clarification of notatio

Prebiotic Homochirality as a Critical Phenomenon

The development of prebiotic homochirality on early-Earth or another planetary platform may be viewed as a critical phenomenon. It is shown, in the context of spatio-temporal polymerization reaction networks, that environmental effects -- be them temperature surges or other external disruptions -- may destroy any net chirality previously produced. In order to understand the emergence of prebiotic homochirality it is important to model the coupling of polymerization reaction networks to different planetary environments.Comment: 6 Pages, 1 Figure, In Press: Origins of Life and Evolution of Biosphere

An Extended Model for the Evolution of Prebiotic Homochirality: A Bottom-Up Approach to the Origin of Life

A generalized autocatalytic model for chiral polymerization is investigated in detail. Apart from enantiomeric cross-inhibition, the model allows for the autogenic (non-catalytic) formation of left and right-handed monomers from a substrate with reaction rates $\epsilon_L$ and $\epsilon_R$, respectively. The spatiotemporal evolution of the net chiral asymmetry is studied for models with several values of the maximum polymer length, N. For N=2, we study the validity of the adiabatic approximation often cited in the literature. We show that the approximation obtains the correct equilibrium values of the net chirality, but fails to reproduce the short time behavior. We show also that the autogenic term in the full N=2 model behaves as a control parameter in a chiral symmetry- breaking phase transition leading to full homochirality from racemic initial conditions. We study the dynamics of the N -> infinity model with symmetric ($\epsilon_L = \epsilon_R$) autogenic formation, showing that it only achieves homochirality for $\epsilon < \epsilon_c$, where $\epsilon_c$ is an N-dependent critical value. For $\epsilon \leq \epsilon_c$ we investigate the behavior of models with several values of N, showing that the net chiral asymmetry grows as tanh(N). We show that for a given symmetric autogenic reaction rate, the net chirality and the concentrations of chirally pure polymers increase with the maximum polymer length in the model. We briefly discuss the consequences of our results for the development of homochirality in prebiotic Earth and possible experimental verification of our findings

The electron electric dipole moment enhancement factors of Rubidium and Caesium atoms

The enhancement factors of the electric dipole moment (EDM) of the ground states of two paramagnetic atoms; rubidium (Rb) and caesium (Cs) which are sensitive to the electron EDM are computed using the relativistic coupled-cluster theory and our results are compared with the available calculations and measurements. The possibility of improving the limit for the electron EDM using the results of our present work is pointed out.Comment: AISAMP7 Conference paper, Accepted in Journal of Physics: Conference Series: 200