A Chandra observation of the H2O megamaser IC2560

A short Chandra ACIS-S observation of the Seyfert 2 galaxy IC 2560, which hosts a luminous nuclear water megamaser, shows: 1) the X-ray emission is extended; 2) the X-ray spectrum shows emission features in the soft (E<2 keV) X-ray band; this is the major component of the extended emission; and 3) a very strong (EW~3.6 keV) iron K line at 6.4 keV on a flat continuum. This last feature clearly indicates that the X-ray source is hidden behind Compton-thick obscuration, so that the intrinsic hard X-ray luminosity must be much higher than observed, probably close to ~3e42 erg/s. We briefly discuss the implications for powering of the maser emission and the central source.Comment: 5 pages, MNRAS in pres

Remodelling of the natural product fumagillol employing a reaction discovery approach

In the search for new biologically active molecules, diversity-oriented synthetic strategies break through the limitation of traditional library synthesis by sampling new chemical space. Many natural products can be regarded as intriguing starting points for diversity-oriented synthesis, wherein stereochemically rich core structures may be reorganized into chemotypes that are distinctly different from the parent structure. Ideally, to be suited to library applications, such transformations should be general and involve few steps. With this objective in mind, the highly oxygenated natural product fumagillol has been successfully remodelled in several ways using a reaction-discovery-based approach. In reactions with amines, excellent regiocontrol in a bis-epoxide opening/cyclization sequence can be obtained by size-dependent interaction of an appropriate catalyst with the parent molecule, forming either perhydroisoindole or perhydroisoquinoline products. Perhydroisoindoles can be further remodelled by cascade processes to afford either morpholinone or bridged 4,1-benzoxazepine-containing structures.P50 GM067041 - NIGMS NIH HHS; P50 GM067041-07 - NIGMS NIH HHS; P50 GM067041-08 - NIGMS NIH HHS; P50 GM067041-09 - NIGMS NIH HH

Quantum Scattering in Two Black Hole Moduli Space

We discuss the quantum scattering process in the moduli space consisting of two maximally charged dilaton black holes. The black hole moduli space geometry has different structures for arbitrary dimensions and various values of dilaton coupling. We study the quantum effects of the different moduli space geometries with scattering process. Then, it is found that there is a resonance state on certain moduli spaces.Comment: 15 pages, 19 figures, RevTeX 3.

Unusual Higgs or Supersymmetry from Natural Electroweak Symmetry Breaking

This review provides an elementary discussion of electroweak symmetry breaking in the minimal and the next-to-minimal supersymmetric models with the focus on the fine-tuning problem -- the tension between natural electroweak symmetry breaking and the direct search limit on the Higgs boson mass. Two generic solutions of the fine-tuning problem are discussed in detail: models with unusual Higgs decays; and models with unusual pattern of soft supersymmetry breaking parameters.Comment: 23 pages, 6 figures; invited review by MPL

Acute and chronic effects of foam rolling vs eccentric exercise on ROM and force output of the plantar flexors

Foam rolling and eccentric exercise interventions have been demonstrated to improve range of motion (ROM). However, these two modalities have not been directly compared. Twenty-three academy soccer players (age: 18 ± 1; height: 1.74 ± 0.08 m; body mass: 69.3 ± 7.5 kg) were randomly allocated to either a foam rolling (FR) or eccentric exercise intervention designed to improve dorsiflexion ROM. Participants performed the intervention daily for a duration of four weeks. Measurements of dorsiflexion ROM, isometric plantar flexion torque and drop jump reactive strength index were taken at baseline (pre-intervention) and at three subsequent time-points (30-min post, 24-hours post and 4-weeks post). A significant time x group interaction effect was observed for dorsiflexion (P = 0.036), but not for torque or reactive strength index. For dorsiflexion, there was a significant increase in both acute (30-min; P < 0.001) and chronic (4-week; P < 0.001) ROM for the eccentric group, whilst FR exhibited only an acute improvement (P < 0.001). Eccentric training would appear a more efficacious modality than foam rolling for improving dorsiflexion ROM in elite academy soccer players

ASCA Observation of an X-Ray-Luminous Active Nucleus in Markarian 231

We have obtained a moderately long (100 kilosecond) ASCA observation of the Seyfert 1 galaxy Markarian 231, the most luminous of the local ultraluminous infrared galaxy (ULIRG) population. In the best-fitting model we do not see the X-ray source directly; the spectrum consists of a scattered power-law component and a reflection component, both of which have been absorbed by a column N_H \approx 3 X 10^(22)/cm^2. About 3/4 of the observed hard X-rays arise from the scattered component, reducing the equivalent width of the iron K alpha line. The implied ratio of 1-10 keV X-ray luminosity to bolometric luminosity, L_x/L_bol \sim 2%, is typical of Sy 1 galaxies and radio-quiet QSOs of comparable bolometric luminosities, and indicates that the bolometric luminosity is dominated by the AGN. Our estimate of the X-ray luminosity also moves Mrk 231 in line with the correlations found for AGN with extremely strong Fe II emission. A second source separated by about 2 arcminutes is also clearly detected, and contributes about 25% of the total flux.Comment: 11 pages, 3 figures; to appear in ApJ Letter

Mapping Children's Discussions of Evidence in Science to Assess Collaboration and Argumentation

The research reported in this paper concerns the development of children's skills of interpreting and evaluating evidence in science. Previous studies have shown that school teaching often places limited emphasis on the development of these skills, which are necessary for children to engage in scientific debate and decision-making. The research, undertaken in the UK, involved four collaborative decision-making activities to stimulate group discussion, each was carried out with five groups of four children (10-11 years old). The research shows how the children evaluated evidence for possible choices and judged whether their evidence was sufficient to support a particular conclusion or the rejection of alternative conclusions. A mapping technique was developed to analyse the discussions and identify different "levels" of argumentation. The authors conclude that suitable collaborative activities that focus on the discussion of evidence can be developed to exercise children's ability to argue effectively in making decisions

One-loop Evolution of a Rolling Tachyon

We study the time evolution of the one-loop diagram in Sen's rolling tachyon background. We find that at least in the long cylinder case they grow rapidly at late time, due to the exponential growth of the timelike oscillator terms in the boundary state. This can also be interpreted as the virtual open string pair creation in the decaying brane. This behavior indicates a breakdown of this rolling tachyon solution at some point during the evolution. We also discuss the closed string emission from this one-loop diagram, and the evolution of a one-loop diagram connecting a decaying brane to a stable brane, which is responsible for the physical open string creation on the stable brane.Comment: 21 pages, 2 figures; v2: references added, comments revised in various places; v3: footnotes 7&8 added, revised version to appear in PR