Reply to N.M. Vegter ‘Discussion on the kinetics of the elution of gold from activated carbon’

Mr Vetger has analysed, in some depth, the approximations made in the treatment of the kinetic data presented in the original by ourselves..

Dephasing of Electrons on Helium by Collisions with Gas Atoms

The damping of quantum effects in the transport properties of electrons deposited on a surface of liquid helium is studied. It is found that due to vertical motion of the helium vapour atoms the interference of paths of duration $t$ is damped by a factor $\exp - (t/\tau_v)^3$. An expression is derived for the weak-localization lineshape in the case that damping occurs by a combination of processes with this type of cubic exponential damping and processes with a simple exponential damping factor.Comment: 7 pages, 2 figures, Revte

The JEM-EUSO Mission

JEM-EUSO is a science mission to explore extremes of the Universe. It observes the dark-side of the Earth and detects UV photons emitted from the extensive air shower caused by an extreme energy particle (about 10(exp 20) eV). Such a particle arrives almost straightly through our Milky Way Galaxy and is expected to allow us to trace the source location by its arrival direction. This will open the door to the new astronomy with charged particles. In its five years operation including the tilted mode, JEM-EUSO will detect at least 1,000 events with E>7 X 10(exp 19) eV and determine the energy spectrum of trans-GZK region with a statistical accuracy of several percent. JEM-EUSO is planned to be transported with HTV (H2 Transfer Vehicle) and attached to the Japanese Experiment Module/ Exposure Facility (JEM/EF) of International Space Station. JAXA has selected JEM-EUSO for one of the mission candidates of the second phase utilization of JEM/EF for the launch of early 2010s. One year-long phase-A study will be carried out under JAXA

The Catchment Runoff Attenuation Flux Tool, a minimum information requirement nutrient pollution model

A model for simulating runoff pathways and water quality fluxes has been developed using the minimum information requirement (MIR) approach. The model, the Catchment Runoff Attenuation Flux Tool (CRAFT), is applicable to mesoscale catchments and focusses primarily on hydrological pathways that mobilise nutrients. Hence CRAFT can be used to investigate the impact of flow pathway management intervention strategies designed to reduce the loads of nutrients into receiving watercourses. The model can help policy makers meet water quality targets and consider methods to obtain “good” ecological status. A case study of the 414 km2 Frome catchment, Dorset, UK, has been described here as an application of CRAFT in order to highlight the above issues at the mesoscale. The model was primarily calibrated on 10-year records of weekly data to reproduce the observed flows and nutrient (nitrate nitrogen – N; phosphorus – P) concentrations. Data from 2 years with sub-daily monitoring at the same site were also analysed. These data highlighted some additional signals in the nutrient flux, particularly of soluble reactive phosphorus, which were not observable in the weekly data. This analysis has prompted the choice of using a daily time step as the minimum information requirement to simulate the processes observed at the mesoscale, including the impact of uncertainty. A management intervention scenario was also run to demonstrate how the model can support catchment managers investigating how reducing the concentrations of N and P in the various flow pathways. This mesoscale modelling tool can help policy makers consider a range of strategies to meet the European Union (EU) water quality targets for this type of catchment

Further investigations of the effects of anti-β2GP1 antibodies on collagen-induced platelet aggregation

Anti-beta-2-glycoprotein 1 (anti-β2GP1) antibodies are associated with increased thrombotic risk in patients with autoimmune disease. There is conflicting evidence on the effects of anti-β2GP1 antibodies on platelets, with both enhanced and inhibited aggregation previously reported. However, previous studies did not include isotype antibodies to ensure the observed effects were due to anti-β2GP1 antibodies. The aims of this study were to (1) investigate the effects of anti-β2GP1 antibodies on collagen-induced platelet aggregation in parallel with negative control (buffer normal saline) and isotype control antibodies and (2) determine the lupus anticoagulant (LA) activity of anti-β2GP1 antibodies used. Three animal-derived anti-human-β2GP1 antibodies (1.25, 2.5, and 5 μg/mL) incubated with healthy platelet-rich plasma were activated by collagen (2.5 μg/mL). Each anti-β2GP1 antibody demonstrated the inhibition of aggregation compared to negative control, but not to isotype control. No anti-β2GP1 antibody demonstrated LA activity, suggesting they were probably nonpathological. This study highlights both negative and isotype control markers are important to validate the effects of anti-β2GP1 antibodies. Assays to measure anti-domain I-β2GP1 antibodies are recommended to be used in conjunction with functional measures to further investigate the effects of anti-β2GP1 antibodies

Synthesis of Mono- and Diiron Dithiolene Complexes as Hydrogenase Models by Dithiolene Transfer Reactions, Including the Crystal Structure of [{Ni(S2C2Ph2)}6]

The dithiolene transfer reaction between the nickel bis(dithiolene) complex [Ni(S2C2Ph2)2] and iron carbonyls has been re-investigated, and the conditions for the production of the dinuclear product [Fe2(μ-S2C2Ph2)(CO)6] have been optimized. Interception of a purple intermediate, thought to be [Fe(CO)3(S2C2Ph2)], in the reaction of [Fe(CO)5] with [Ni(S2C2Ph2)2] by the addition of PPh3 affords the new dark blue mononuclear complex [Fe(CO)2(PPh3)(S2C2Ph2)] in good yield. The fate of the nickel dithiolene fragments in these reactions has also been established by crystallographic characterization of the hexamer [{Ni(S2C2Ph2)}6] and the trinuclear cluster [Ni3(μ-S2C2Ph2)3(PPh3)2]. The substitution reactions of [Fe2(μ-S2C2Ph2)(CO)6] with PPh3 in the presence of Me3NO to give monosubstituted [Fe2(μ-S2C2Ph2)(CO)5(PPh3)] and disubstituted [Fe2(μ-S2C2Ph2)(CO)4(PPh3)2] are also reported

Mode locking of semiconductor laser with curved waveguide and passive mode expander

Active mode locking is reported for a 1.55 μm semiconductor laser with a curved waveguide and passive mode expander, placed in a wavelength tunable external cavity. One facet with a very low reflectivity of 8×10−6 is achieved through a curved active region that tapers into an underlying passive waveguide, thus expanding the mode to give reduced divergence. 10 GHz pulses of 3.1 ps duration have been generated, with a linewidth of 0.81 nm

Deuteron Electroweak Disintegration

We study the deuteron electrodisintegration with inclusion of the neutral currents focusing on the helicity asymmetry of the exclusive cross section in coplanar geometry. We stress that a measurement of this asymmetry in the quasi elastic region is of interest for an experimental determination of the weak form factors of the nucleon, allowing one to obtain the parity violating electron neutron asymmetry. Numerically, we consider the reaction at low momentum transfer and discuss the sensitivity of the helicity asymmetry to the strangeness radius and magnetic moment. The problems coming from the finite angular acceptance of the spectrometers are also considered.Comment: 30 pages, Latex, 7 eps figures, submitted to Phys.Rev.C e-mail: [email protected] , [email protected]

Comparison of measured and predicted bandwidth of graded-index multimode fibres

Measurements of pulse spreading in three graded index fibers have been performed over an extensive range of wavelengths, including regions in which the index profiles become optimal and the bandwidths correspondingly high. The refractive index distributions and profile dispersion parameter have been measured and used in a ray-tracing algorithm in order to predict bandwidths. Comparison reveals that averaging processes on the index data are usually necessary to account for noncircularity of the fiber and small variations in the deduced profile caused by the wavelength dependence of the near-field intensity distribution. Results obtained by this means usually tend to slightly underestimate the true fiber bandwidth, while alpha-profile predictions always result in overestimates by about one order of magnitude. Remaining discrepancies between measured and predicted bandwidths are attributed to small variations of the index profiles along the fiber length

Sleep apnoea and daytime function in the elderly—what is the impact of arousal frequency?

AbstractArousals from sleep result in hyperventilation and hypocapnia that can lead to sleep apnoea. We have investigated whether sleep apnoea in the elderly is associated with more arousals compared with younger people. Additionally, the impact of arousals on daytime symptoms was noted. Four groups (n=11) of elderly (>65 years) and young (<39 years) apnoeic (EA and YA), and age-matched non-apnoeics (EN and YN) were studied. The arousal index (AI) and apnoea/hypopnoea index were determined from polysomnography. Sleepiness (Epworth Sleepiness Scale) and Quality of life (QoL, SF-36) were assessed. The mean (sd) AI was: EN 23.1 (7.6), EA 46.5 (8.8), YN 13.2 (6.6), YA 38.5 (12.1) events/h. AI was higher in the elderly (P=0.002) and in apnoeics (P=0.001); however, the increase in AI associated with sleep apnoea was not age dependent (P=0.73). The influence of sleep apnoea on sleepiness was similar in both age groups. YA but not EA reported reduced physical functioning (P=0.04), vitality (P=0.007) and general health (P=0.04) compared to non-apnoeics. We conclude that (1) the effect of sleep apnoea on arousal is no greater in the elderly compared to the young (2) despite similar levels of sleepiness, elderly apneoics perceive a reduced loss of QoL compared to younger patients