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A striking new species of Begonia, B. joshii, is described from Amazonas Region, Peru. The new species is unusual among the South American members of the genus both in its combination of tuberous habit with peltate leaves and in living in a seasonally dry tropical forest environment. A phylogeny of this and closely related species is presented, and its sectional affiliation and IUCN conservation status are discussed. A key to the peltate Peruvian species of Begonia is provided.
The role played by gas compressibility in gas-cushioned liquid–solid impacts is investigated within a viscous gas and inviscid liquid regime. A full analysis of the energy conservation in the gas is conducted for the first time, which indicates that both thermal diffusion across the gas film and viscous dissipation play an important role in gas cushioning once gas compression becomes significant. Consequently existing models of gas compressibility based on either an isothermal or an adiabatic equation of state for the gas do not fully reflect the physics associated with this phenomenon. Models incorporating thermal diffusion and viscous dissipation are presented, which are appropriate for length scales consistent with droplet impacts, and for larger scale liquid–solid impacts. The evolution of the free surface is calculated alongside the corresponding pressure, temperature and density profiles. These profiles indicate that a pocket of gas can become trapped during an impact. Differences between the new model and older models based on isothermal and adiabatic equations of state are discussed, along with predictions of the size of the trapped gas pocket.
An experimental and theoretical investigation of the air trapping by a blunt, locally spherical body impacting onto the free surface of water is conducted. In the parameter regime previously studied theoretically by Hicks & Purvis (J. Fluid Mech., vol. 649, 2010, pp. 135–163), excellent agreement between experimental data and theoretical modelling is obtained. Earlier predictions of the radius of the trapped air pocket are confirmed. A boundary element method is used to consider air cushioning of an impact of an axisymmetric body into water. Efficient computational methods are obtained by analytically integrating the boundary integral equation over the azimuthal variable. The resulting numerically computed free-surface profiles predict an annular touchdown region in excellent agreement with the experiments.
Droplet deformation by air cushioning prior to impact is considered. A model is presented coupling the free-surface deformation of a droplet with the pressure field in the narrow air layer generated as a droplet approaches an impact. The model is based upon the density and viscosity in the air being small compared with those in the liquid. Additionally, the Reynolds number, defined using the droplet radius ℛ and approach velocity l, is such that lubrication forces dominate in the air layer. In the absence of significant surface tension or compressibility effects, these assumptions lead to coupled nonlinear integro-differential equations describing the evolution of a droplet free surface approaching a solid wall through air, with or without topography.
The problem is studied numerically with a boundary-element method in the inviscid droplet coupled with a finite-difference method in the lubricating air. In normal impacts, air cushioning will be shown to deflect the free surface upwards, delaying the moment of touchdown and trapping a bubble. The volume of the bubble is found to be (μg4/3ℛ5/3/ρl4/3l4/3), where μg is the gas viscosity and ρl is the liquid density and the numerically computed pre-factor = 94.48. Bubble volumes predicted by this relationship are shown to be in good agreement with experimental observations. In oblique impact or impact with a moving surface with sufficient horizontal motion a bubble is not trapped beneath the approaching droplet. In this case, the region of touchdown is initially crescent shaped with air effects accelerating the moment of touchdown.
Effectiveness of repetitive transcranial magnetic stimulation (rTMS) for major depression is unclear. The authors performed a randomized controlled trial comparing real and sham adjunctive rTMS with 4-month follow-up.
Fifty-nine patients with major depression were randomly assigned to a 10-day course of either real (n=29) or sham (n=30) rTMS of the left dorsolateral prefrontal cortex (DLPFC). Primary outcome measures were the 17-item Hamilton Depression Rating Scale (HAMD) and proportions of patients meeting criteria for response (⩾50% reduction in HAMD) and remission (HAMD⩽8) after treatment. Secondary outcomes included mood self-ratings on Beck Depression Inventory-II and visual analogue mood scales, Brief Psychiatric Rating Scale (BPRS) score, and both self-reported and observer-rated cognitive changes. Patients had 6-week and 4-month follow-ups.
Overall, Hamilton Depression Rating Scale (HAMD) scores were modestly reduced in both groups but with no significant group×time interaction (p=0.09) or group main effect (p=0.85); the mean difference in HAMD change scores was −0.3 (95% CI −3.4 to 2.8). At end-of-treatment time-point, 32% of the real group were responders compared with 10% of the sham group (p=0.06); 25% of the real group met the remission criterion compared with 10% of the sham group (p=0.2); the mean difference in HAMD change scores was 2.9 (95% CI −0.7 to 6.5). There were no significant differences between the two groups on any secondary outcome measures. Blinding was difficult to maintain for both patients and raters.
Adjunctive rTMS of the left DLPFC could not be shown to be more effective than sham rTMS for treating depression.
The initial stages of high-velocity droplet impact on a shallow water layer are described, with special emphasis given to the spray jet mechanics. Four stages of impact are delineated, with appropriate scalings, and the successively more important influence of the base is analysed. In particular, there is a finite time before which part of the water in the layer remains under the droplet and after which all of the layer is ejected in the splash jet.
Selected isolates of Phytophthora infestans from around England and Wales were fingerprinted using both RG57, a multi-locus RFLP probe, and Amplified Fragment Length Polymorphisms (AFLPs). The larger number of polymorphisms detectable with the AFLP method allowed resolution of several similar AFLP genotypes among isolates with identical RG57 fingerprints. However, some isolates with the same RG57 genotype had remarkably dissimilar AFLP genotypes, suggesting that there has been convergent evolution of some RG57 fingerprints. Also, some isolates with dissimilar RG57 fingerprints had similar or identical AFLP fingerprints. Both techniques distinguished isolates of mitochondrial DNA haplotype Ia from those of haplotype IIa. However, with AFLPs only, most of the isolates of A2 mating type were very similar and were distinguished from those of A1 mating type, suggesting that gene flow between A1 and A2 genotypes is limited and that sexual recombination is rare.
Jewish and Christian writings of the Roman period bear witness to the existence of a sizeable non-Jewish yet allegedly Israelite sect in the territory of Samaria. The centre of the religious life of this community was Mount Gerizim and the cities and villages adjacent to it, although its constituents were also to be found elsewhere in Palestine and in a diaspora in the Mediterranean world which extended as far as Rome. These ‘Samaritans’ claimed to be the descendants of the old Israelite tribes of Ephraim, Manasseh, and Levi, and contended that they had faithfully worshipped the ancestral Hebrew God in their spiritual centre at Gerizim from the time of the Israelite conquest of Canaan to that very day. Their community had had, or so they claimed, a continuous and unbroken history throughout this long period. They further maintained that the true centre of Israelite worship had always been, and always should be, at Mount Gerizim. They thus viewed the religion of the descendants of the tribe of Judah, which had Jerusalem as its spiritual centre, as an aberration of the classical Yahwistic faith. Essentially, what the Samaritan community claimed for itself was what the Jewish community claimed for itself: that it was the Israel of God constituted by the Mosaic legislation and sustained by obedience to its precepts. Ultimately, the issue which separated Samaritans and Jews was the question of the true holy place, Jerusalem or Shechem. Neither community was inclined to grant to the other any consideration which might represent acquiescence in the contention between these mutally antithetical positions.
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