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

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

P- and T-violating Schiff moment of the Mercury nucleus

The Schiff moment of the $^{199}$Hg nucleus was calculated using finite range P- and T-violating weak nucleon-nucleon interaction. Effects of the core polarization were considered in the framework of RPA with effective residual forces.Comment: 10 pages and 2 figures,to appear in Yad. Fi

Toroidal quadrupole transitions associated to collective rotational-vibrational motions of the nucleus

In the frame of the algebraic Riemann Rotational Model one computes the longitudinal, transverse and toroidal multipoles corresponding to the excitations of low-lying levels in the ground state band of several even-even nuclei by inelastic electron scattering (e,e'). Related to these transitions a new quantity, which accounts for the deviations from the Siegert theorem, is introduced. The intimate connection between the nuclear vorticity and the dynamic toroidal quadrupole moment is underlined. Inelastic differential cross-sections calculated at backscattering angles shows the dominancy of toroidal form-factors over a broad range of momentum transfer.Comment: 11 pages in LaTex, 3 figures available by fax or mail, accepted for publication in J.Phys.

Measurement of the electron electric dipole moment using YbF molecules

The most sensitive measurements of the electron electric dipole moment d_e have previously been made using heavy atoms. Heavy polar molecules offer a greater sensitivity to d_e because the interaction energy to be measured is typically 10^3 times larger than in a heavy atom. We report the first measurement of this kind, for which we have used the molecule YbF. Together, the large interaction energy and the strong tensor polarizability of the molecule make our experiment essentially free of the systematic errors that currently limit d_e measurements in atoms. Our first result d_e = (- 0.2 \pm 3.2) x 10^-26 e.cm is less sensitive than the best atom measurement, but is limited only by counting statistics and demonstrates the power of the method.Comment: 4 pages, 4 figures. v2. Minor corrections and clarifications made in response to referee comment

Enhancement of the electric dipole moment of the electron in PbO

The a(1) state of PbO can be used to measure the electric dipole moment of the electron d_e. We discuss a semiempirical model for this state, which yields an estimate of the effective electric field on the valence electrons in PbO. Our final result is an upper limit on the measurable energy shift, which is significantly larger than was anticipated earlier: $2|W_d|d_e \ge 2.4\times 10^{25} \textrm{Hz} [ \frac{d_e}{e \textrm{cm}} ]$.Comment: 4 pages, revtex4, no figures, submitted to PR

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

Dissociation in a polymerization model of homochirality

A fully self-contained model of homochirality is presented that contains the effects of both polymerization and dissociation. The dissociation fragments are assumed to replenish the substrate from which new monomers can grow and undergo new polymerization. The mean length of isotactic polymers is found to grow slowly with the normalized total number of corresponding building blocks. Alternatively, if one assumes that the dissociation fragments themselves can polymerize further, then this corresponds to a strong source of short polymers, and an unrealistically short average length of only 3. By contrast, without dissociation, isotactic polymers becomes infinitely long.Comment: 16 pages, 6 figures, submitted to Orig. Life Evol. Biosp

Field-theoretical approach to particle oscillations in absorbing matter

The $ab$ oscillations in absorbing matter are considered. The standard model based on optical potential does not describe the total $ab$ transition probability as well as the channel corresponding to absorption of the $b$-particle. We calculate directly the off-diagonal matrix element in the framework of field-theoretical approach. Contrary to one-particle model, the final state absorption does not tend to suppress the channels mentioned above or, similarly, calculation with hermitian Hamiltonian leads to increase the corresponding values. The model reproduces all the results on the particle oscillations, however it is oriented to the description of the above-mentioned channels. Also we touch on the problem of infrared singularities. The approach under study is infrared-free.Comment: 27 pages, 8 figure

Homochiral growth through enantiomeric cross-inhibition

The stability and conservation properties of a recently proposed polymerization model are studied. The achiral (racemic) solution is linearly unstable once the relevant control parameter (here the fidelity of the catalyst) exceeds a critical value. The growth rate is calculated for different fidelity parameters and cross-inhibition rates. A chirality parameter is defined and shown to be conserved by the nonlinear terms of the model. Finally, a truncated version of the model is used to derive a set of two ordinary differential equations and it is argued that these equations are more realistic than those used in earlier models of that form.Comment: 20 pages, 6 figures, Orig. Life Evol. Biosph. (accepted