ALBERT

Notes: An all-weather ruggedized and simplified version of the IMST/SA–CNRS improved Lyman-alpha hygrometer has been developed in cooperation with Risø National Laboratory to measure the small-scale, high-frequency fluctuations of humidity at an open-sea research platform. This version is characterized by the integration of the photomultiplier detection electronics inside the support and by a casings design especially adapted to operation in adverse conditions. Comparisons with other fast hygrometers during the HEXOS Main Experiment indicate that this instrument has probably, to date, the best sensitivity, signal-to-noise ratio, and effective frequency limit. It is able to measure the entire inertioconvective subrange of scales and probably, under some conditions, a part of the dissipation range.

Notes: Zusammenfassung Es wurden sowohl ältere als auch neuere Verfahren zur Fällung von Kalziumhydroxyapatit aus wässriger Lösung vergleichend überprüft und die erhaltenen Präparate mittels chemischer und physikalischer Methoden charakterisiert, wobei sich ergab, dass das vom National Bureau of Standards entwickelte Verfahren die am besten definierten Kristalle liefert.

Notes: Abstract. For a model of three particles on a line, subject to attractive delta-function interactions, we consider the phase shift. We do this from the point of view of the calculation of the S-matrix in a hyperspherical adiabatic basis (an adiabatic S-matrix), and for energies ranging from the (negative) energy of the two-body bound state to a total energy of zero. We derive analytical expansions and present numerical work, for different approximations, and compare with the exact results that we obtain from the work of McGuire, whose model we have borrowed. We show that the simplest adiabatic approximation gives results that are qualitatively wrong, but that better approximations yield, for most of our range, excellent agreement with the exact result. Understanding the threshold behaviour, however, requires a zero-energy three-body bound state, or resonance, previously unsuspected for this model. The methods developed for the case of the simplest adiabatic approximation also yield threshold and low-energy results applicable to the two-body problem in two dimensions.

Notes: Abstract We obtain a set of four-dimensional hyperspherical harmonics in closed form. These harmonics are not only quantized with respect to the rotation group (O 2), but are an irreducible basis for the permutation groupS 3. An additional symmetry is found which allows us to write hyperspherical harmonics classified with respect to a 12 element groupS 3×i×O 2. We give a set of three mutually commuting operators whose eigenvalues uniquely characterize each spherical harmonic with respect to degree, symmetry, and angular momentum in the plane.

Notes: Abstract. The objective of the study was to corroborate or refute the hypothesis that farmers having a high intake of organic grown commodities have a high semen quality due to their expected lower level of dietary pesticides intake. Food frequency data and semen were collected from 256 farmers (171 traditional farmers and 85 organic farmers, overall participation rate: 32%) who were selected from central registers. Each farmer delivered one semen sample before the spraying season started. The farmers were divided into three groups where the commodities from organic production contributed no (N, 0%), medium (M, 1–49%), or a high (H, 50–100%) proportion of the fruit and vegetables consumed. Farmers having a high relative intake of organically grown fruit and vegetables also had a high relative consumption of organically produced meat, milk, and bread, and differences were observed comparing the actual mean intake of single commodities, such as rice, potato, and pork meat. The current individual dietary intake of 40 pesticides was estimated using food frequencies and generalized serving size data in combination with data on pesticide concentrations in food commodities as obtained from the National Danish Food Monitoring Program. The estimated pesticide intake was significantly lower among farmers of group H, but for all three groups of farmers the average dietary intake of 40 pesticides was at or below 1% of the acceptable daily intake (ADI) except for the dithiocarbamates (max = 0.21 μg/kg day = 2.2% ADI), methidathion, (max = 0.01 μg/kg day = 1.4% ADI), and 2-phenylphenol (max = 0.21 μg/kg day = 1.1% ADI). The median sperm concentration for the three groups of farmers was not significantly different (p = 0.40, median sperm concentration was N = 62, M = 44, and H = 75 million/ml). The group of men without organic food intake had a significant lower proportion of morphologically normal spermatozoa, but in relation to 14 other semen parameters no significant differences were found between the groups. Intake of 40 individual pesticides was correlated with four semen parameters (concentration, percentage dead spermatozoa, percentage normal sperm heads, and motility [VCL]). Five significant correlations (p value 0.01) were found among the 160 comparisons in relation to percentage dead spermatozoa: azinphos-methyl, carbaryl, chlorfenson, fenitrothion, and tetradifon. For all of them a lower percentage of dead spermatozoa were found in the groups with a high dietary intake of the specific pesticide. In contrast, for all pesticides evaluated only minor differences were found between the groups when considering spermatozoa concentration, morphology, and motility. In conclusion, the estimated dietary intake of 40 pesticides did not entail a risk of impaired semen quality, but precautions should be taken when generalizing this negative result to populations with a higher dietary exposure level or an intake of other groups of pesticides.

Notes: Abstract In the integro-differential-equation approach (IDEA) and its associated hyperspherical-harmonic expansion method (HHEM) terms appear involving the potential for a single pair of particles. This introduces a spurious component in the potential that is eliminated in the Schrödinger equation by summing over all pairs. We calculate the contribution of this spurious potential in the solution of the HHEM for an even number of bosons in the ground state, using the Afnan-Tang S3 and Malfliet-Tjon MT5 interactions.

Notes: Abstract We propose a hyperspherical adiabatic formalism for the calculation of the 3-to-3S-matrix at low energy, for repulsive potentials, and use it then in a model calculation. That is for McGuire's model (3 particles in one dimension subject to repulsive delta-function interactions), we use analytical expressions for the hyperspherical adiabatic basis, the adiabatic coupling matrix elements, and eigenpotentials to obtain the first terms of the exactS-matrix analytically, in an expansion in powers of the wave number. We were able to associate the definite powers ofq in the expansion of theS-matrix to the corresponding inverse powers of ρ in the expansions of the adiabatic eigenpotentials and coupling matrix elements. We investigate the effect of making the “usual” approximations found in the literature (extreme and uncoupled adiabatic approximations), when calculating the diagonal and off-diagonalS-matrix elements. Finally, we show that the coupled adiabatic equations uncouple as the energy goes to zero.

Notes: Abstract We examine, anddiscuss, the basic procedure (the “trick” needed in 1, 2 pr 3 dimensions) to calculate 3 to 3 scattering using hypersherical harmonics. To illustrate this, we look at three particles in a plane, subject to finite repulsive core interactions, and obtain, numerically, long-range adiabatic effective potentials. Their asymptotic behaviour is such as to provide the correct (nonanalytic) low-energy dependence of the three-body phase shifts. We note that the expansion is not uniform in the number of harmonics needed as the hyperadius changes. and that the asymptotic behaviour of the converged effective potentials differs from that of the matrix elements.

Notes: Abstract The use of high frequency atmospheric turbulence properties (inertial subrange spectra, structure function parameters or dissipation rates) to infer surface fluxes of momentum, sensible heat and latent heat is more practical for most ocean going platforms than direct covariance measurement. The relationships required to deduce the fluxes from such data are examined in detail in this paper and several ambiguities and uncertainties are identified. It is noted that, over water, data on water vapor properties (the dimensionless functions for the mean profile, the structure function parameter and the variance transport term) are extremely sparse and the influence of sea spray is largely unknown. Special attention is given to flux estimation on the basis of the structure function formalism. Existing knowledge about the relevant similarity functions is summarized and discussed in light of the ambiguities identified above.

Notes: Summary Varying degrees of phosphate depletion by plants and AER were brought about in two acid soils. After depletion, the monocalcium phosphate potential was determined in soil suspended in dilute CaCl2 solution. The results showed that phosphate depletion either by plants or AER did not change the phosphate potential of a soil. It seemed that some of the labile phosphate removed by plants was replaced by a mobilization of non-labile soil phosphate fraction in the soil. The constancy of the phosphate potential indicated that the concentration of phosphate in the soil solution was controlled by the solubility of sparingly soluble soil phosphates. The data implied that it was the solubility of hydroxyapatite which determined the phosphate potential of both soils.