515 research outputs found

    The WHAM Northern Sky Survey and the Nature of the Warm Ionized Medium in the Galaxy

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    The Wisconsin H-Alpha Mapper (WHAM) has completed a velocity-resolved map of diffuse H-alpha emission of the entire northern sky, providing the first comprehensive picture of both the distribution and kinematics of diffuse ionized gas in the Galaxy. WHAM continues to advance our understanding of the physical conditions of the warm ionized medium through observations of other optical emission lines throughout the Galactic disk and halo. We discuss some highlights from the survey, including an optical window into the inner Galaxy and the relationship between HI and HII in the diffuse ISM.Comment: 9 pages, 3 figures. To be published in "How does the Galaxy work?", eds. E.J. Alfaro, E. Perez & J. Franco, Kluwer, held 23-27 June 2003 in Granada, Spain. Higher resolution version available at http://www.astro.wisc.edu/~madsen/prof/pubs.htm

    Ionization of Infalling Gas

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    H-alpha emission from neutral halo clouds probes the radiation and hydrodynamic conditions in the halo. Armed with such measurements, we can explore how radiation escapes from the Galactic plane and how infalling gas can survive a trip through the halo. The Wisconsin H-Alpha Mapper (WHAM) is one of the most sensitive instruments for detecting and mapping optical emission from the ISM. Here, we present recent results exploring the ionization of two infallling high-velocity complexes. First, we report on our progress mapping H-alpha emission covering the full extent of Complex A. Intensities are faint (<100 mR; EM <0.2 pc cm^-6 but correlate on the sky and in velocity with 21-cm emission. Second, we explore the ionized component of some Anti-Center Complex clouds studied by Peek et al. (2007) that show dynamic shaping from interaction with the Galactic halo.Comment: 4 pages, 2 figures; to appear in proceedings of "The Role of Disk-Halo Interaction in Galaxy Evolution: Outflow vs Infall?" held in Espinho, Portugal during 2008 Augus

    Is the Sun Embedded in a Typical Interstellar Cloud?

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    The physical properties and kinematics of the partially ionized interstellar material near the Sun are typical of warm diffuse clouds in the solar vicinity. The interstellar magnetic field at the heliosphere and the kinematics of nearby clouds are naturally explained in terms of the S1 superbubble shell. The interstellar radiation field at the Sun appears to be harder than the field ionizing ambient diffuse gas, which may be a consequence of the low opacity of the tiny cloud surrounding the heliosphere. The spatial context of the Local Bubble is consistent with our location in the Orion spur.Comment: "From the Outer Heliosphere to the Local Bubble", held at International Space Sciences Institute, October 200

    Lowered-intensity preparative regimen for allogeneic stem cell transplantation delays acute graft-versus-host disease but does not improve outcome for advanced hematologic malignancy

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    AbstractReduced conditioning intensity has extended the option of allogeneic hematopoietic stem cell transplantation to patients who cannot tolerate fully myeloablative regimens. However, relapse and graft-versus-host disease (GVHD) continue to be major causes of morbidity and mortality. We prospectively tested whether a moderate reduction of the intensity of the preparative regimen would lead to significant reduction in regimen-related toxicity without compromising tumor control in a cohort of 44 patients ineligible for conventional hematopoietic stem cell transplantation. Patients were conditioned with fludarabine, busulfan, mycophenolate, and total lymphoid irradiation. Tacrolimus and methotrexate were given as prophylaxis for GVHD. Donors were 5 of 6 or 6 of 6 matched family members. The median age was 61 years. Eleven patients had comorbid conditions that precluded conventional myeloablative transplantation. Fatal regimen-related organ toxicity occurred in 3 patients. The cumulative incidence of grade 2 to 4 or grade 3 to 4 acute GVHD by day 100 was 38% (95% confidence interval [CI] = 25%, 55%) and 20% (95% CI = 10%, 39%), respectively, with a median time to onset of 66 days. For the entire cohort, 1-year overall survival, disease-free survival, and relapse rates were 54% (95% CI = 41%, 71%), 47% (95% CI = 35%, 65%), and 37% (95% CI = 19%, 51%), respectively. Outcomes differed based on stage of disease at time of transplantation, advanced (n = 19) versus nonadvanced (n = 25). Median survival times were 138 days and 685 days for subjects with advanced and nonadvanced disease, respectively (P = .005). After adjusting for age and comorbidity, disease stage continued to be significantly associated with overall survival (P = .005). In conclusion, a moderate reduction in conditioning dose intensity resulted in delayed onset of acute GVHD (compared with historical controls). A reduction in conditioning intensity is associated with poor survival for patients with advanced-stage disease, highlighting the importance of the conditioning regimen for tumor control. © 2003 American Society for Blood and Marrow TransplantationBiology of Blood and Marrow Transplantation 9:189-197 (2003

    The Detection of Incipient Caries with Tracer Dyes

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    The purpose of this study was to determine the increase in color contrast produced by the use of a tracer dye in detection of incipient caries lesions with transillumination. Twenty four caries-free first premolars were immersed in an acid gelatin for production of artificial incipient caries lesions. After the lesions had developed, these teeth were photographed by transillumination. Two photographs were taken of each tooth. The first photograph showed the lesion without dye. A blue tracer dye was then added and absorbed by the lesion, and a second photograph was taken. The data on the color difference were obtained by use of a reflectance colorimeter and showed a four-fold increase between the lesion and surrounding area with the dye. A two-way analysis of variance was used for the statistical interpretation. The color difference between the lesion without the dye and then with the dye was significant. The use of the blue tracer dye, therefore, significantly increased the contrast in the images of the artificial incipient lesions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68289/2/10.1177_00220345890680021101.pd

    Striatal mRNA expression patterns underlying peak dose L-DOPA-induced dyskinesia in the 6-OHDA hemiparkinsonian rat

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    L-DOPA is the primary pharmacological treatment for relief of the motor symptoms of Parkinson’s disease (PD). With prolonged treatment (⩾5 years) the majority of patients will develop abnormal involuntary movements as a result of L-DOPA treatment, known as L-DOPA-induced dyskinesia. Understanding the underlying mechanisms of dyskinesia is a crucial step toward developing treatments for this debilitating side effect. We used the 6-hydroxydopamine (6-OHDA) rat model of PD treated with a three-week dosing regimen of L-DOPA plus the dopa decarboxylase inhibitor benserazide (4 mg/kg and 7.5 mg/kg s.c., respectively) to induce dyskinesia in 50% of individuals. We then used RNA-seq to investigate the differences in mRNA expression in the striatum of dyskinetic animals, non-dyskinetic animals, and untreated parkinsonian controls at the peak of dyskinesia expression, 60 min after L-DOPA administration. Overall, 255 genes were differentially expressed; with significant differences in mRNA expression observed between all three groups. In dyskinetic animals 129 genes were more highly expressed and 14 less highly expressed when compared with non-dyskinetic and untreated parkinsonian controls. In L-DOPA treated animals 42 genes were more highly expressed and 95 less highly expressed when compared with untreated parkinsonian controls. Gene set cluster analysis revealed an increase in expression of genes associated with the cytoskeleton and phosphoproteins in dyskinetic animals compared with non-dyskinetic animals, which is consistent with recent studies documenting an increase in synapses in dyskinetic animals. These genes may be potential targets for drugs to ameliorate L-DOPA-induced dyskinesia or as an adjunct treatment to prevent their occurrence

    Pilot Trial on the Use of Etanercept and Methylprednisolone as Primary Treatment for Acute Graft-versus-Host Disease

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    AbstractClinical and preclinical data indicate that tumor necrosis factor (TNF)–α is an important mediator of acute graft-versus-host disease (aGVHD) after allogeneic bone marrow transplantation. We completed a study using etanercept, a fusion protein capable of neutralizing TNF-α, for the initial treatment of aGVHD. Etanercept (25 mg subcutaneously) was administered twice weekly for 16 doses, along with methylprednisolone (2 mg/kg) and tacrolimus for biopsy-proven aGVHD. Twenty patients with a median age of 47 years (range, 8–63 years) were enrolled. Fourteen patients with grade II aGVHD (11 family donors and 3 unrelated donors) and 6 patients with grade III aGVHD (3 family donors and 3 unrelated donors) were treated. Twelve patients completed 16 doses of therapy, and 8 received 5 to 15 doses. Reasons for not completing all doses of etanercept included progression of aGVHD (n = 4), relapsed leukemia (n = 2), progression of pulmonary and central nervous system lesions (n = 1), and perforated duodenal ulcer (n = 1). Fifteen (75%) of 20 patients had complete resolution of aGVHD within 4 weeks of therapy. Increasing levels of soluble TNF receptor 1 plasma concentration during the first 4 weeks of therapy indicated progression of aGVHD in 5 patients. In contrast, for 15 responding patients, soluble TNF receptor 1 plasma concentration levels returned to baseline. These data demonstrate the feasibility of using cytokine blockade in the early treatment of aGVHD

    The Intentional Use of Service Recovery Strategies to Influence Consumer Emotion, Cognition and Behaviour

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    Service recovery strategies have been identified as a critical factor in the success of. service organizations. This study develops a conceptual frame work to investigate how specific service recovery strategies influence the emotional, cognitive and negative behavioural responses of . consumers., as well as how emotion and cognition influence negative behavior. Understanding the impact of specific service recovery strategies will allow service providers' to more deliberately and intentionally engage in strategies that result in positive organizational outcomes. This study was conducted using a 2 x 2 between-subjects quasi-experimental design. The results suggest that service recovery has a significant impact on emotion, cognition and negative behavior. Similarly, satisfaction, negative emotion and positive emotion all influence negative behavior but distributive justice has no effect

    Fast variability from black-hole binaries

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    Currently available information on fast variability of the X-ray emission from accreting collapsed objects constitutes a complex phenomenology which is difficult to interpret. We review the current observational standpoint for black-hole binaries and survey models that have been proposed to interpret it. Despite the complex structure of the accretion flow, key observational diagnostics have been identified which can provide direct access to the dynamics of matter motions in the close vicinity of black holes and thus to the some of fundamental properties of curved spacetimes, where strong-field general relativistic effects can be observed.Comment: 20 pages, 11 figures. Accepted for publication in Space Science Reviews. Also to appear in hard cover in the Space Sciences Series of ISSI "The Physics of Accretion onto Black Holes" (Springer Publisher

    Magnetic fields in cosmic particle acceleration sources

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    We review here some magnetic phenomena in astrophysical particle accelerators associated with collisionless shocks in supernova remnants, radio galaxies and clusters of galaxies. A specific feature is that the accelerated particles can play an important role in magnetic field evolution in the objects. We discuss a number of CR-driven, magnetic field amplification processes that are likely to operate when diffusive shock acceleration (DSA) becomes efficient and nonlinear. The turbulent magnetic fields produced by these processes determine the maximum energies of accelerated particles and result in specific features in the observed photon radiation of the sources. Equally important, magnetic field amplification by the CR currents and pressure anisotropies may affect the shocked gas temperatures and compression, both in the shock precursor and in the downstream flow, if the shock is an efficient CR accelerator. Strong fluctuations of the magnetic field on scales above the radiation formation length in the shock vicinity result in intermittent structures observable in synchrotron emission images. Resonant and non-resonant CR streaming instabilities in the shock precursor can generate mesoscale magnetic fields with scale-sizes comparable to supernova remnants and even superbubbles. This opens the possibility that magnetic fields in the earliest galaxies were produced by the first generation Population III supernova remnants and by clustered supernovae in star forming regions.Comment: 30 pages, Space Science Review
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