Hubble Space Telescope Ultraviolet Imaging and High-Resolution Spectroscopy of Water Photodissociation Products in Comet Hyakutake (C/1996 B2)

Comet Hyakutake (C/1996 B2) provided a target of opportunity for performing a systematic study of water photodissociation products in which we obtained data from three instruments on the Hubble Space Telescope (HST). The HST Goddard High Resolution Spectrograph (GHRS) was used to measure the line profile of hydrogen Lyα (H Lyα) at six locations around the coma of the comet, ranging from the nucleus to a displacement of 100,000 km, and covering different directions compared with the comet-sun line. GHRS yielded line profiles with a spectral resolution (FWHM ~4 km s^(-1)) that was a factor of 2-3 better than any previous H Lyα or Hα ground-based measurements. The Wide Field Planetary Camera 2 (WFPC2) and the Woods filter were used to obtain H Lyα images of the inner coma. The faint object spectrograph (FOS) was used to determine the OH production rate and monitor its variation throughout the HST observing sequence. The GHRS H Lyα line profiles show the behavior of a line profile that is optically thick in the core for positions near the nucleus (<5000 km) and gradually becoming more optically thin at larger displacements and lower column abundances. A composite H Lyα image constructed from four separate WFPC2 exposures is consistent with the relative fluxes seen in GHRS observations and clearly shows the dayside enhancement of a solar illuminated optically thick coma. These data were analyzed self-consistently to test our understanding of the detailed physics and chemistry of the expanding coma and our ability to obtain accurate water production rates from remote observations of gaseous hydrogen (H) and hydroxyl (OH), the major water dissociation products. Our hybrid kinetic/hydrodynamic model of the coma combined with a spherical radiative transfer calculation is able to account for (1) the velocity distribution of H atoms, (2) the spatial distribution of the H Lyα emission in the inner coma, and (3) the absolute intensities of H and OH emissions, giving a water production rate of (2.6 ± 0.4) × 10^(29) s^(-1) on 1996 April 4

Calcitonin gene-related peptide receptor antagonist BIBN 4096 BS for the acute treatment of migraine

Background: Calcitonin gene–related peptide (CGRP) may have a causative role in migraine. We therefore hypothesized that a CGRP-receptor antagonist might be effective in the treatment of migraine attacks. Methods: In an international, multicenter, double-blind, randomized clinical trial of BIBN 4096 BS, a highly specific and potent nonpeptide CGRP-receptor antagonist, 126 patients with migraine received one of the following: placebo or 0.25, 0.5, 1, 2.5, 5, or 10 mg of BIBN 4096 BS intravenously over a period of 10 minutes. A group-sequential adaptive treatment-assignment design was used to minimize the number of patients exposed. Results: The 2.5-mg dose was selected, with a response rate of 66 percent, as compared with 27 percent for placebo (P=0.001). The BIBN 4096 BS group as a whole had a response rate of 60 percent. Significant superiority over placebo was also observed with respect to most secondary end points: the pain-free rate at 2 hours; the rate of sustained response over a period of 24 hours; the rate of recurrence of headache; improvement in nausea, photophobia, phonophobia, and functional capacity; and the time to meaningful relief. An effect was apparent after 30 minutes and increased over the next few hours. The overall rate of adverse events was 25 percent after the 2.5-mg dose of the drug and 20 percent for the BIBN 4096 BS group as a whole, as compared with 12 percent for placebo. The most frequent side effect was paresthesia. There were no serious adverse events. Conclusions: The CGRP antagonist BIBN 4096 BS was effective in treating acute attacks of migraine

Qualification Procedures of the CMS Pixel Barrel Modules

The CMS pixel barrel system will consist of three layers built of about 800 modules. One module contains 66560 readout channels and the full pixel barrel system about 48 million channels. It is mandatory to test each channel for functionality, noise level, trimming mechanism, and bump bonding quality. Different methods to determine the bump bonding yield with electrical measurements have been developed. Measurements of several operational parameters are also included in the qualification procedure. Among them are pixel noise, gains and pedestals. Test and qualification procedures of the pixel barrel modules are described and some results are presented.Comment: 7 Pages, 7 Figures. Contribution to Pixel 2005, September 5-8, 2005, Bonn, Germna

Stepwise RNP assembly at the site of H/ACA RNA transcription in human cells

Mammalian H/ACA RNPs are essential for ribosome biogenesis, premessenger RNA splicing, and telomere maintenance. These RNPs consist of four core proteins and one RNA, but it is not known how they assemble. By interrogating the site of H/ACA RNA transcription, we dissected their biogenesis in single cells and delineated the role of the non-core protein NAF1 in the process. NAF1 and all of the core proteins except GAR1 are recruited to the site of transcription. NAF1 binds one of the core proteins, NAP57, and shuttles between nucleus and cytoplasm. Both proteins are essential for stable H/ACA RNA accumulation. NAF1 and GAR1 bind NAP57 competitively, suggesting a sequential interaction. Our analyses indicate that NAF1 binds NAP57 and escorts it to the nascent H/ACA RNA and that GAR1 then replaces NAF1 to yield mature H/ACA RNPs in Cajal bodies and nucleoli

Mutual induction of magnetic 3d and 4f order in multiferroic hexagonal ErMnO3

The complex interplay between the 3d and 4f moments in hexagonal ErMnO3 is investigated by magnetization, optical second harmonic generation, and neutron-diffraction measurements. We revise the phase diagram and provide a microscopic model for the emergent spin structures with a special focus on the intermediary phase transitions. Our measurements reveal that the 3d exchange between Mn^{3+} ions dominates the magnetic symmetry at 10 K < T < T_N with Mn^3+ order according to the Gamma_4 representation triggering 4f ordering according to the same representation on the Er^{3+}(4b) site. Below 10 K the magnetic order is governed by 4f exchange interactions of Er^{3+} ions on the 2a site. The magnetic Er^{3+}(2a) order according to the representation Gamma_2 induces a magnetic reorientation (Gamma_4 --> Gamma_2) at the Er^{3+}(4b) and the Mn^{3+} sites. Our findings highlight the fundamentally different roles the Mn^{3+}, R^{3+}(2a), and R^{3+}(4b) magnetism play in establishing the magnetic phase diagram of the hexagonal RMnO3 system

Quality of life in survivors after cervical artery dissection

Background and purpose : Little data exists about longterm outcome, quality of life (QOL) and its predictors after spontaneous cervical artery dissections (sCAD). Methods : Clinical and radiological data of 114 patients with sCAD were collected prospectively. Six patients died within 3 months, the remaining 108 were contacted after a mean of 1498 days (range: 379-3455), 99 survivors (92 %) replied. QOL, assessed with the stroke-specific QOL scale (SSQOL), and functional abilities, measured with modified Rankin Scale (mRS) were compared, and predictors of QOL were analyzed. Subgroup analyses were performed for patients with ischemic stroke, those with isolated local symptoms or transient ischemic symptoms and those without significant disabilities (mRS 0-1) at follow-up. Results : Seventy-one of 99 patients (72 %) had no significant disability, but only 53 (54 %) reported a good QOL (SS-QOL ≥ 4). Compared to the self-rated premorbid QOL of all patients, SS-QOL was impaired after sCAD (p 0.5). High National Institute of Health Stroke Scale score on admission and higher age were independent predictors of impaired QOL (p < 0.05). Conclusion : QOL is impaired in almost half of long-term survivors after sCAD, even in patients with local or transient symptoms or without functional disability. Impairment of QOL is a surprisingly frequent long-term sequela after sCAD and deserves attention as an outcome measure in these patient

Age-dependent differences in demographics, risk factors, co-morbidity, etiology, management, and clinical outcome of acute ischemic stroke

Background : Comparisons between younger and older stroke patients including comorbidities are limited. Methods : Prospective data of consecutive patients with first ever acute ischemic stroke were compared between younger (≤ 45 years) and older patients (> 45 years). Results : Among 1004 patients, 137 (14 %) were ≤ 45 years. Younger patients were more commonly female (57 % versus 34 %; p < 0.0001), had a lower frequency of diabetes (1 % versus 15 %; p < 0.0001), hypercholesterolemia (26 % versus 56 %; p < 0.0001), hypertension (19 % versus 65 %; p < 0.0001), coronary heart disease (14 % versus 40 %; p < 0.0001), and a lower mean Charlson co-morbidity index (CCI), (0.18 versus 0.84; p < 0.0001). Tobacco use was more prevalent in the young (39 % versus 26 %; P < 0.0001). Large artery disease (2 % versus 21 %; p < 0.0001), small artery disease (3 % versus 12 %; p = 0.0019) and atrial fibrillation (1 % versus 17 %; p = 0.001) were less common in young patients, while other etiologies (31 % versus 9 %; p < 0.0001), patent foramen ovale or atrial septal defect (44 % versus 26 %; p < 0.0001), and cervical artery dissection (26 % versus 7 %; p < 0.0001) were more frequent. A favorable outcome (mRS 0 or 1) was more common (57.4 % versus 46.9 %; p = 0.023), and mortality (5.1 % versus 12 %; p = 0.009) was lower in the young. After regression analysis, there was no independent association between age and outcome (p = 0.206) or mortality (p = 0.073). Baseline NIHSS score (p < 0.0001), diabetes (p = 0.041), and CCI (p = 0.002) independently predicted an unfavorable outcome. Conclusions : Younger patients were more likely to be female, had different risk factors and etiologies and fewer co-morbidities. There was no independent association between age and clinical outcome or mortalit