Charge Stripping Reactions in Mass Spectrometry: A Study of Diatomic and Triatomic Inorganic and Organic Ions

Charge stripping reactions of the type m• + N--+ m2• + N + ehave been studied for a variety of diatomic and triatomic inorganic and organic ions. Ionisation energies of the m• ions, IE (m+--+ m2• ), have been determined, most of them for the first time. The method is fast and straightforward; it is applicable to both molecular and fragment .ions. The relative cross-sections for the charge stripping processes have been also determined; they show llrge variations from one species to another. Cases of possible interferences, which are fairly infrequent, are described and discussed

Probing Spectral Line Gradients Beyond One Effective Radius in NGC 3610

The outer region (0.75--1.25 r_e in the B-band) of the merger-remnant elliptical NGC 3610 is studied using extremely high signal to noise Keck spectra, with a supplementary spectrum of the galaxy center. Stellar population parameters -- age, [Z/H], [$\alpha$/Fe] -- are measured in several apertures along the slit. Using the multi-index simultaneous fitting method of Proctor et al. (2004), no significant stellar population gradients are detected in the outer parts of the galaxy. The overall gradients relative to the galaxy center are consistent with those found in many other early-type galaxies, though the metallicity gradient is much steeper than would be expected if NGC 3610 formed in a major merger event. Standard analysis methods using the H$\beta$ index are found to produce spurious radially variable gradients.Comment: 15 pages, 9 figures, accepted by A

Contrasting arbuscular mycorrhizal communities colonizing different host plants show a similar response to a soil phosphorus concentration gradient

High soil phosphorus (P) concentration is frequently shown to reduce root colonization by arbuscular mycorrhizal (AM) fungi, but the influence of P on the diversity of colonizing AM fungi is uncertain. We used terminal restriction fragment length polymorphism (T-RFLP) of 18S rDNA and cloning to assess diversity of AM fungi colonizing maize (Zea mays), soybean (Glycene max) and field violet (Viola arvensis) at three time points in one season along a P gradient of 10–280 mg l−1 in the field. Percentage AM colonization changed between sampling time points but was not reduced by high soil P except in maize. There was no significant difference in AM diversity between sampling time points. Diversity was reduced at concentrations of P > 25 mg l−1, particularly in maize and soybean. Both cloning and T-RFLP indicated differences between AM communities in the different host species. Host species was more important than soil P in determining the AM community, except at the highest P concentration. Our results show that the impact of soil P on the diversity of AM fungi colonizing plants was broadly similar, despite the fact that different plants contained different communities. However, subtle differences in the response of the AM community in each host were evident

Behavioural interventions for primary and secondary dysmenorrhoea

Background: Dysmenorrhoea refers to the occurrence of painful menstrual cramps of uterine origin and is a common gynaecological condition with considerable morbidity. The behavioural approach assumes that psychological and environmental factors interact with, and influence, physiological processes. Behavioural interventions for dysmenorrhoea may include both physical and cognitive procedures and focus on both physical and psychological coping strategies for dysmenorrhoeic symptoms rather than modification of any underlying organic pathology. Objectives: To determine the effectiveness of any behavioural interventions for the treatment of primary or secondary dysmenorrhoea when compared to each other, placebo, no treatment, or conventional medical treatments for example non-steroidal anti-inflammatory drugs (NSAIDs). Search strategy: We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register (searched April 2005), Cochrane Central Register of Controlled Trials (CENTRAL on The Cochrane Library, Issue 2, 2005), MEDLINE (1966 to April 2005), EMBASE (1980 to April 2005), Social Sciences Index (1980 to April 2005), PsycINFO (1972 to April 2005) and CINAHL (1982 to April 2005) and reference lists of articles. Selection criteria: Randomised controlled trials comparing behavioural interventions with placebo or other interventions in women with dysmenorrhoea. Data collection and analysis: Two authors independently assessed trial quality and extracted data. Main results: Five trials involving 213 women were included. Behavioural intervention vs control: One trial of pain management training reported reduction in pain and symptoms compared to a control. Three trials of relaxation compared to control reported varied results, two trials showed no difference in symptom severity scores however one trial reported relaxation was effective for reducing symptoms in menstrual sufferers with spasmodic symptoms. Two trials reported less restriction in daily activities following treatment with either relaxation of pain management training compared to a control. One trial also reported less time absent from school following treatment wit pain management training compared to a control. Behavioural intervention vs other behavioural interventions: Three trials showed no difference between behavioural interventions for the outcome of improvement in symptoms. One trial showed that relaxation resulted in a decrease in the need for resting time compared to the relaxation and imagery. Authors' conclusions: There is some evidence from five RCTs that behavioural interventions may be effective for dysmenorrhoea however results should be viewed with caution as they varied greatly between trials due to inconsistency in the reporting of data, small trial size, poormethodological quality and age of the trials

Nonlinear Competition Between Small and Large Hexagonal Patterns

Recent experiments by Kudrolli, Pier and Gollub on surface waves, parametrically excited by two-frequency forcing, show a transition from a small hexagonal standing wave pattern to a triangular ``superlattice'' pattern. We show that generically the hexagons and the superlattice wave patterns bifurcate simultaneously from the flat surface state as the forcing amplitude is increased, and that the experimentally-observed transition can be described by considering a low-dimensional bifurcation problem. A number of predictions come out of this general analysis.Comment: 4 pages, RevTex, revised, to appear in Phys. Rev. Let

Fluctuation dynamo and turbulent induction at low magnetic Prandtl numbers

This paper is a detailed report on a programme of simulations used to settle a long-standing issue in the dynamo theory and demonstrate that the fluctuation dynamo exists in the limit of large magnetic Reynolds number Rm>>1 and small magnetic Prandtl number Pm<<1. The dependence of the critical Rm_c vs. the hydrodynamic Reynolds number Re is obtained for 1<Re<6700. In the limit Pm<<1, Rm_c is ~3 times larger than for Pm>1. The stability curve Rm_c(Re) (and, it is argued, the nature of the dynamo) is substantially different from the case of the simulations and liquid-metal experiments with a mean flow. It is not as yet possible to determine numerically whether the growth rate is ~Rm^{1/2} in the limit Re>>Rm>>1, as should be the case if the dynamo is driven by the inertial-range motions. The magnetic-energy spectrum in the low-Pm regime is qualitatively different from the Pm>1 case and appears to develop a negative spectral slope, although current resolutions are insufficient to determine its asymptotic form. At 1<Rm<Rm_c, the magnetic fluctuations induced via the tangling by turbulence of a weak mean field are investigated and the possibility of a k^{-1} spectrum above the resistive scale is examined. At low Rm<1, the induced fluctuations are well described by the quasistatic approximation; the k^{-11/3} spectrum is confirmed for the first time in direct numerical simulations.Comment: IoP latex, 27 pages, 25 figures, 3 tables. Accepted by New J. Physic