Nickel electrode plate thickening study

The rate of thickening of the nickel electrode with cycling, under geochronous conditions, was investigated. The experimental procedures used to study the effects of various operational parameters on the rate of the thickness growth are outlined. The parameters included temperature, electrolyte composition, manufacturing lot, cycle parameters, and reconditioning methods

Storage-ring measurement of the hyperfine induced 47Ti18+(2s 2p 3P0 -> 2s2 1S0) transition rate

The hyperfine induced 2s 2p 3P0 > 2s2 1S0 transition rate AHFI in berylliumlike 47Ti18+ was measured. Resonant electron-ion recombination in a heavy-ion storage ring was employed to monitor the time dependent population of the 3P0 state. The experimental value AHFI=0.56(3)/s is almost 60% larger than theoretically predicted.Comment: 4 pages. 3 figures, 1 table, accepted for publication in Physical Review Letter

Trial incentive in sequential litigation

We analyze when and why trials can emerge in equilibrium when a defendant may sequentially face multiple plaintiffs. Subsequent potential plaintiffs learn about their chances of winning from the initial trial outcome. A trial in the initial case is like an experiment that the defendant can run that would induce plaintiffs’ learning. We show that the initial case can go to trial in equilibrium when a favorable trial outcome for the defense can deter potential future plaintiffs from filing lawsuits. The possibility of meritless lawsuits further raises the attraction of trials. We also show that when the initial plaintiff’s attorney may represent future clients, trials are more likely both because the attorney gains from learning, and because his ability to attract future clients may depend on how much his initial client receives.postprin

Four cytotoxic N4-substituted thiosemicarbazones derived from 2-hydroxynaphthalene-1-carboxaldehyde

The X-ray crystal structures are reported of four novel and potentially O,N,S-tridentate donor ligands that demonstrate antitumour activity. These ligands are 1-[(4-methylthiosemicarbazono)methyl]-2-naphthol, C13H13N3OS, (III), 1-[(4-ethylthiosemicarbazono)methyl]-2-naphthol, C14H15N3OS, (IV), 1-[(4-phenylthiosemicarbazono)methyl]-2-naphthol, C18H15N3OS, (V), and 1-[(4,4-dimethylthiosemicarbazono)methyl]-2-naphthol dimethyl sulfoxide solvate, C14H15N3OS.C2H6OS, (VI). These chelators are N4-substituted thiosemicarbazones, each based on the same parent aldehyde, namely 2-zhydroxynaphthalene-1-carboxaldehyde isonicotinoylhydrazone. Conformational variations within this series are discussed in relation to the optimum conformation for metal-ion binding

Absolute rate coefficients for photorecombination and electron-impact ionization of magnesium-like iron ions from measurements at a heavy-ion storage ring

Rate coefficients for photorecombination (PR) and cross sections for electron-impact ionization (EII) of Fe$^{14+}$ forming Fe$^{13+}$ and Fe$^{15+}$, respectively, have been measured by employing the electron-ion merged-beams technique at a heavy-ion storage ring. Rate coefficients for PR and EII of Fe$^{14+}$ ions in a plasma are derived from the experimental measurements. Simple parametrizations of the experimentally derived plasma rate coefficients are provided for use in the modeling of photoionized and collisionally ionized plasmas. In the temperature ranges where Fe$^{14+}$ is expected to form in such plasmas the latest theoretical rate coefficients of Altun et al. [Astron. Astrophys. 474, 1051 (2007)] for PR and of Dere [Astron. Astrophys. 466, 771 (2007)] for EII agree with the experimental results to within the experimental uncertainties. Common features in the PR and EII resonance structures are identified and discussed.Comment: 12 pages, 6 figures, 3 tables, submitted for publication to Physical Review

Impacts of Land Abandonment on Vegetation: Successional Pathways in European Habitats

Changes in traditional agricultural systems in Europe in recent decades have led to widespread abandonment and colonization of various habitats by shrubs and trees. We combined several vegetation databases to test whether patterns of changes in plant diversity after land abandonment in different habitats followed similar pathways. The impacts of land abandonment and subsequent woody colonization on vegetation composition and plant traits were studied in five semi-natural open habitats and two arable habitats in six regions of Europe. For each habitat, vegetation surveys were carried out in different stages of succession using either permanent or non-permanent plots. Consecutive stages of succession were defined on a physiognomic basis from initial open stages to late woody stages. Changes in vegetation composition, species richness, numbers of species on Red Lists, plant strategy types, Ellenberg indicator values of the vegetation, Grime CSR strategy types and seven ecological traits were assessed for each stage of the successional pathway. Abandonment of agro-pastoral land-use and subsequent woody colonization were associated with changes in floristic composition. Plant richness varied according to the different habitats and stages of succession, but semi-natural habitats differed from arable fields in several ecological traits and vegetation responses. Nevertheless, succession occurred along broadly predictable pathways. Vegetation in abandoned arable fields was characterized by a decreasing importance of R-strategists, annuals, seed plants with overwintering green leaves, insect-pollinated plants with hemi-rosette morphology and plants thriving in nutrient-rich conditions, but an increase in species considered as endangered according to the Red Lists. Conversely, changes in plant traits with succession within the initially-open semi-natural habitats showed an increase in plants thriving in nutrient-rich conditions, stress-tolerant plants and plants with sexual and vegetative reproduction, but a sharp decrease in protected species. In conclusion, our study showed a set of similarities in responses of the vegetation in plant traits after land abandonment, but we also highlighted differences between arable fields and semi-natural habitats, emphasizing the importance of land-use legacy

Femtochemistry of mass-selected negative-ion clusters of dioxygen: Charge-transfer and solvation dynamics

Femtosecond, time-resolved photoelectron spectroscopy is used to investigate the dissociation dynamics of mass-selected anionic molecular-oxygen clusters. The observed transient photoelectron signal for the clusters (O_2)^−_n  (n = 3–5) shows the O^−_2 production; for n = 1 and 2, we observe no time-dependence at this wavelength of 800 nm. The observed transients are bi-exponential in form with two distinct time constants, but with clear trends, for all investigated cluster sizes. These striking observations describe the reaction pathways of the solvated core and we elucidate two primary processes: Charge transfer with concomitant nuclear motion, and direct dissociation of the O^−_4 core-ion via electron recombination; the former takes 700–2700 fs, while the latter is on a shorter time scale, 110–420 fs. Both rates decrease differently upon increasing cluster size, indicating the critical role of step-wise solvation

Macroinvertebrate community responses to a dewatering disturbance gradient in a restored stream

Dewatering disturbances are common in aquatic systems and represent a relatively untapped field of disturbance ecology, yet studying dewatering events along gradients in non-dichotomous (i.e. wet/dry) terms is often difficult. Because many stream restorations can essentially be perceived as planned hydrologic manipulations, such systems can make ideal test-cases for understanding processes of hydrological disturbance. In this study we used an experimental drawdown in a 440 ha stream/wetland restoration site to assess aquatic macroinvertebrate community responses to dewatering and subsequent rewetting. The geomorphic nature of the site and the design of the restoration allowed dewatering to occur predictably along a gradient and decoupled the hydrologic response from any geomorphic (i.e. habitat heterogeneity) effects. In the absence of such heterogeneous habitat refugia, reach-scale wetted perimeter and depth conditions exerted a strong control on community structure. The community exhibited an incremental response to dewatering severity over the course of this disturbance, which was made manifest not as a change in community means but as an increase in community variability, or dispersion, at each site. The dewatering also affected inter-species abundance and distributional patterns, as dewatering and rewetting promoted alternate species groups with divergent habitat tolerances. Finally, our results indicate that rapid rewetting – analogous to a hurricane breaking a summer drought – may represent a recovery process rather than an additional disturbance and that such processes, even in newly restored systems, may be rapid