Development of an analytical method for the determination of extractable nitroaromatics and nitramines in soils

An analytical method was developed to determine the concentrations of HMX, RDX, TNB, DNB, tetryl, TNT and 2,4-DNT in soil. The method relies on solvent extraction with analysis by reversed-phase liquid chromatography. The extraction step was studied in terms of process kinetics and recovery. Two solvents (acetonitrile and methanol) and four extraction techniques (Soxhlet, ultrasonic bath, mechanical shaker and homogenizer-sonicator) were compared. Ultrasonic bath extraction with acetonitrile was selected based on extraction kinetics, overall analyte recovery, sample throughput, and instability of analytes at elevated temperature. The rate of extraction of analytes from field-contaminated soil was shown to be much slower than from spiked soils, indicating it is unwise to develop extraction procedures based solely on spiked materials. A number of possible separations were examined. Adequate separation of the seven analytes was achieved on an LC-18 column eluted with 1:1 methanol/water with a run time under 15 minutes. Confirmation of analyte identities was recommended on LC-CN, also eluted with 1:1 methanol/water. Elution orders on the two columns were quite different due to different mechanisms of separation. Additional tests were conducted to assess various sample processing alternatives. Removal of particulates from soil extracts was achieved by dilution of extracts 1:1 with aqueous CaCl\sb2. This resulted in flocculation of suspended particles, which were then easy to remove by settling and filtration. Stock standards were stable for at least a year, working standards at least 28 days, and soil extracts at least two months. Care needs to be taken to ensure that air drying of soil, prior to extraction, is not conducted in direct sunlight; otherwise losses of TNT and an increase in photochemical transformation products will result. The overall method provides linear calibration curves over a wide range of analyte concentrations. Detection limits ranged from 0.03 to 1.27 $\mu$g/g with no extract preconcentration. Recovery of spiked analyte was better than 80% for all analytes tested. The method was successfully tested in two collaborating laboratories

SU(3) Clebsch-Gordan Coefficients for Baryon-Meson Coupling at Arbitrary N_c

We present explicit formulae for the SU(3) Clebsch-Gordan coefficients that are relevant for the couplings of large N_c baryons to mesons. In particular, we compute the Clebsch-Gordan series for the coupling of the octet (associated with mesons, and remains the correct representation at large N_c) to the large N_c analogs of the baryon octet and decuplet representations.Comment: 8 pages, no figures, ReVTe

SU(3) Baryon Resonance Multiplets in Large N_c QCD

We extend the recently developed treatment of baryon resonances in large N_c QCD to describe resonance multiplets collected according to the SU(3) flavor symmetry that includes strange quarks. As an illustration we enumerate the SU(3) partners of a hypothetical J^P = 1/2^{+/-} resonance in the SU(3) representation that reduces to 10-bar when N_c = 3, and reproduce results hitherto obtained only in the context of a large N_c quark picture. While these specific quantum numbers represent one favored set for the possible pentaquark state Theta^+ (1540), the method is applicable to baryon resonances with any quantum numbers.Comment: 14 pages, ReVTe

Peculiar Velocities of Galaxy Clusters

We investigate the peculiar velocities predicted for galaxy clusters by theories in the cold dark matter family. A widely used hypothesis identifies rich clusters with high peaks of a suitably smoothed version of the linear density fluctuation field. Their peculiar velocities are then obtained by extrapolating the similarly smoothed linear peculiar velocities at the positions of these peaks. We test these ideas using large high resolution N-body simulations carried out within the Virgo supercomputing consortium. We find that at early times the barycentre of the material which ends up in a rich cluster is generally very close to a high peak of the initial density field. Furthermore the mean peculiar velocity of this material agrees well with the linear value at the peak. The late-time growth of peculiar velocities is, however, systematically underestimated by linear theory. At the time clusters are identified we find their rms peculiar velocity to be about 40% larger than predicted. Nonlinear effects are particularly important in superclusters. These systematics must be borne in mind when using cluster peculiar velocities to estimate the parameter combination $\sigma_8\Omega^{0.6}$.Comment: 8 pages, 4 figures; submitted to MNRA

How primary care can contribute to good mental health in adults.

The need for support for good mental health is enormous. General support for good mental health is needed for 100% of the population, and at all stages of life, from early childhood to end of life. Focused support is needed for the 17.6% of adults who have a mental disorder at any time, including those who also have a mental health problem amongst the 30% who report having a long-term condition of some kind. All sectors of society and all parts of the NHS need to play their part. Primary care cannot do this on its own. This paper describes how primary care practitioners can help stimulate such a grand alliance for health, by operating at four different levels - as individual practitioners, as organisations, as geographic clusters of organisations and as policy-makers