The curve complex and covers via hyperbolic 3-manifolds

Rafi and Schleimer recently proved that the natural relation between curve complexes induced by a covering map between two surfaces is a quasi-isometric embedding. We offer another proof of this result using a distance estimate via hyperbolic 3-manifolds.Comment: 5 page

Kosovo after the ICJ opinion

Non

Isotope Effects in Complex Scattering Lengths for He Collisions With Molecular Hydrogen

We examine the effect of theoretically varying the collision-system reduced mass in collisions of He with vibrationally excited molecular hydrogen and observe zero-energy resonances for select atomic “hydrogen” masses less than 1 u or a “helium” mass of 1.95 u. Complex scattering lengths, state-to-state vibrational quenching cross sections, and a low-energy elastic scattering resonance are all studied as a function of collision-system reduced mass. Experimental observations of these phenomena in the cold and ultracold regimes for collisions of $^{3}$He and $^{4}$He with H$_{2}$, HD, HT, and DT should be feasible in the near future.Astronom

Energy Transfer and Trapping in Red-Chlorophyll-Free Photosystem I from Synechococcus WH 7803

We report for the first time steady-state and time-resolved emission properties of photosystem I (PSI) complexes isolated from the cyanobacterial strain Synechococcus WH 7803. The PSI complexes from this strain display an extremely small fluorescence emission yield at 77 K, which we attribute to the absence of so-called red antenna chlorophylls, chlorophylls with absorption maxima at wavelengths longer than those of the primary electron donor P700. Emission measurements at room temperature with picosecond time resolution resulted in two main decay components with lifetimes of about 7.5 and 18 ps and spectra peaking at about 685 nm. Especially in the red flanks, these spectra show consistent differences, which means that earlier proposed models for the primary charge separation reactions based on ultrafast (∼1 ps) excitation equilibration processes cannot describe the data. We show target analyses of a number of alternative models and conclude that a simple model (Ant2)* (Ant1/RC)* → RP2 can explain the time-resolved emission data very well. In this model, (Ant2)* represents chlorophylls that spectrally equilibrate in about 7.5 ps and in which RP2 represents the "final" radical pair P70

Analysis of VNTR loci amplified by the polymerase chain reaction for investigating the origin of intimal smoth muscle cells in a coronary artery lesion developing after heart transplantation in man

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Directional atherectomy for treatment of restenosis within coronary stents: clinical, angiographic and histologic results

Abstract OBJECTIVES: The safety and long-term results of directional coronary atherectomy in stented coronary arteries were determined. In addition, tissue studies were performed to characterize the development of restenosis. METHODS: Directional coronary atherectomy was performed in restenosed stents in nine patients (10 procedures) 82 to 1,179 days after stenting. The tissue was assessed for histologic features of restenosis, smooth muscle cell phenotype, markers of cell proliferation and cell density. A control (no stenting) group consisted of 13 patients treated with directional coronary atherectomy for restenosis 14 to 597 days after coronary angioplasty, directional coronary atherectomy or laser intervention. RESULTS: Directional coronary atherectomy procedures within the stent were technically successful with results similar to those of the initial stenting procedure (2.31 +/- 0.38 vs. 2.44 +/- 0.35 mm). Of five patients with angiographic follow-up, three had restenosis requiring reintervention (surgery in two and repeat atherectomy followed by laser angioplasty in one). Intimal hyperplasia was identified in 80% of specimens after stenting and in 77% after coronary angioplasty or atherectomy. In three patients with stenting, 70% to 76% of the intimal cells showed morphologic features of a contractile phenotype by electron microscopy 47 to 185 days after coronary intervention. Evidence of ongoing proliferation (proliferating cell nuclear antigen antibody studies) was absent in all specimens studied. Although wide individual variability was present in the maximal cell density of the intimal hyperplasia, there was a trend toward a reduction in cell density over time. CONCLUSIONS: Although atherectomy is feasible for the treatment of restenosis in stented coronary arteries and initial results are excellent, recurrence of restenosis is common. Intimal hyperplasia is a nonspecific response to injury regardless of the device used and accounts for about 80% of cases of restenosis. Smooth muscle cell proliferation and phenotypic modulation toward a contractile phenotype are early events and largely completed by the time of clinical presentation of restenosis. Restenotic lesions may be predominantly cellular, matrix or a combination at a particular time after a coronary procedure

Rapidly evolving aerosol emissions are a dangerous omission from near-term climate risk assessments

Anthropogenic aerosol emissions are expected to change rapidly over the coming decades, driving strong, spatially complex trends in temperature, hydroclimate, and extreme events both near and far from emission sources. Under-resourced, highly populated regions often bear the brunt of aerosols’ climate and air quality effects, amplifying risk through heightened exposure and vulnerability. However, many policy-facing evaluations of near-term climate risk, including those in the latest Intergovernmental Panel on Climate Change assessment report, underrepresent aerosols’ complex and regionally diverse climate effects, reducing them to a globally averaged offset to greenhouse gas warming. We argue that this constitutes a major missing element in society’s ability to prepare for future climate change. We outline a pathway towards progress and call for greater interaction between the aerosol research, impact modeling, scenario development, and risk assessment communities