2,359 research outputs found
Aerodynamic characteristics of a 142-inch diameter solid rocket booster, configuration 139 (SA2FA/SA2FB)
Tests of a 2.112 percent scale model of the space shuttle solid rocket booster model were conducted in a transonic pressure tunnel. Tests were conducted at Mach numbers ranging from 0.4 to 1.2, angles of attack from minus one degree to plus 181 degrees, and Reynolds numbers from 0.6 million to 6.1 million per foot. The model configurations investigated were as follows: (1) solid rocket booster without external protuberances, (2) solid rocket booster with an electrical tunnel and a solid rocket booster/external tank thrust attachment structure, and (3) solid rocket booster with two body strakes
The Molecular Interstellar Medium in Ultraluminous Infrared Galaxies
We present CO observations of a large sample of ultraluminous IR galaxies out
to z = 0.3. Most of the galaxies are interacting, but not completed mergers.
All but one have high CO(1-0) luminosities, log(Lco [K-km/s-pc^2]) = 9.92 +/-
0.12. The dispersion in Lco is only 30%, less than that in the FIR luminosity.
The integrated CO intensity correlates Strongly with the 100 micron flux
density, as expected for a black body model in which the mid and far IR
radiation are optically thick. We use this model to derive sizes of the FIR and
CO emitting regions and the enclosed dynamical masses. Both the IR and CO
emission originate in regions a few hundred parsecs in radius. The median value
of Lfir/Lco = 160 Lsun/(K-km/s-pc^2), within a factor of two of the black body
limit for the observed FIR temperatures. The entire ISM is a scaled up version
of a normal galactic disk with densities a factor of 100 higher, making even
the intercloud medium a molecular region. Using three different techniques of
H2 mass estimation, we conclude that the ratio of gas mass to Lco is about a
factor of four lower than for Galactic molecular clouds, but that the gas mass
is a large fraction of the dynamical mass. Our analysis of CO emission reduces
the H2 mass from previous estimates of 2-5e10 Msun to 0.4-1.5e10 Msun, which is
in the range found for molecular gas rich spiral galaxies. A collision
involving a molecular gas rich spiral could lead to an ultraluminous galaxy
powered by central starbursts triggered by the compression of infalling
preexisting GMC's.Comment: 34 pages LaTeX with aasms.sty, 14 Postscript figures, submitted to
ApJ Higher quality versions of Figs 2a-f and 7a-c available by anonymous FTP
from ftp://sbast1.ess.sunysb.edu/solomon/
Prognostic factors for disease progression in advanced Hodgkin's disease: an analysis of patients aged under 60 years showing no progression in the first 6 months after starting primary chemotherapy.
The aim of this study was to determine whether a very high-risk group based on presenting characteristics could be identified in patients with advanced Hodgkin's disease who may benefit from high-dose chemotherapy (HDCT). Between 1975 and 1992, 453 previously untreated patients aged under 60 years who did not progress in the first 6 months after the start of standard chemotherapy had their hospital notes reviewed. The outcomes analysed were early disease progression (in the 6- to 18-month window following the start of chemotherapy) and disease progression in the whole of the follow-up period. A Cox regression analysis was used to investigate the combined effects of a number of presenting characteristics on these outcomes. Despite the presence of factors with significant effects on the relative rate of progression, the absolute effects in a group identified as having the poorest prognosis were not especially poor. No group could be defined with a freedom from progression rate of less than 70% over 6-18 months, and the worst prognostic group, which included only 53 patients, had an overall freedom from progression rate of 57% at 5 years. Four other reported prognostic indices were evaluated using our data set, but none of the indices was more successful in identifying a very high-risk group. It has not been possible to define a sufficiently high-risk group of patients with Hodgkin's disease based on presenting characteristics for whom HDCT could be advised as part of primary treatment. The search for more discriminating prognostic factors identifying vulnerable patients with a high risk of relapse must continue before a role can be found for HDCT following conventional chemotherapy in patients without disease progression
Unfolding dynamics of proteins under applied force
Understanding the mechanisms of protein folding is a major challenge that is being addressed effectively by collaboration between researchers in the physical and life sciences. Recently, it has become possible to mechanically unfold proteins by pulling on their two termini using local force probes such as the atomic force microscope. Here, we present data from experiments in which synthetic protein polymers designed to mimic naturally occurring polyproteins have been mechanically unfolded. For many years protein folding dynamics have been studied using chemical denaturation, and we therefore firstly discuss our mechanical unfolding data in the context of such experiments and show that the two unfolding mechanisms are not the same, at least for the proteins studied here. We also report unexpected observations that indicate a history effect in the observed unfolding forces of polymeric proteins and explain this in terms of the changing number of domains remaining to unfold and the increasing compliance of the lengthening unstructured polypeptide chain produced each time a domain unfolds
Detection of squirrel poxvirus by nested and real-time PCR from red (Sciurus vulgaris) and grey (Sciurus carolinensis) squirrels
<p>Abstract</p> <p>Background</p> <p>Squirrel poxvirus (SQPV) is highly pathogenic to red squirrels (<it>Sciurus vulgaris</it>), and is a significant contributing factor to the local extinction of the species in most parts of England and Wales, where infection is endemic in Eastern grey squirrel (<it>Sciurus carolinensis</it>) populations. Although a nested PCR assay has been used successfully to study the epidemiology of SQPV, samples have a long processing time and the assay is not quantifiable.</p> <p>Results</p> <p>This project describes the design and optimization of a real-time PCR for SQPV. Comparison with the nested PCR showed the real-time assay to be more sensitive by one log and able to detect approximately 144 genome copies per mg of tissue.</p> <p>Conclusions</p> <p>The real-time PCR has been used to quantify viral genome load in tissues from diseased and apparently healthy red and grey squirrels, and suggests that the titre of virus in tissues from diseased red squirrels is considerably higher than that found even in a grey squirrel with cutaneous lesions.</p
Positron Emission Tomography Score Has Greater Prognostic Significance Than Pretreatment Risk Stratification in Early-Stage Hodgkin Lymphoma in the UK RAPID Study.
PURPOSE: Accurate stratification of patients is an important goal in Hodgkin lymphoma (HL), but the role of pretreatment clinical risk stratification in the context of positron emission tomography (PET) -adapted treatment is unclear. We performed a subsidiary analysis of the RAPID trial to assess the prognostic value of pretreatment risk factors and PET score in determining outcomes. PATIENTS AND METHODS: Patients with stage IA to IIA HL and no mediastinal bulk underwent PET assessment after three cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine; 143 PET-positive patients (PET score, 3 to 5) received a fourth doxorubicin, bleomycin, vinblastine, and dacarbazine cycle and involved-field radiotherapy, and 419 patients in complete metabolic remission were randomly assigned to receive involved-field radiotherapy (n = 208) or no additional treatment (n = 211). Cox regression was used to investigate the association between PET score and pretreatment risk factors with HL-specific event-free survival (EFS). RESULTS: High PET score was associated with inferior EFS, before (P .4). CONCLUSION: In RAPID, a positive PET scan did not carry uniform prognostic weight; only a PET score of 5 was associated with inferior outcomes. This suggests that in future trials involving patients without B symptoms or mediastinal bulk, a score of 5 rather than a positive PET result should be used to guide treatment escalation in early-stage HL
Prognostic factors in high and intermediate grade non-Hodgkin's lymphoma.
An analysis of prognostic factors has been performed on 260 patients with high and intermediate grade non-Hodgkin's lymphoma (NHL) treated over an 11-year period between 1975 and 1986. The overall 5-year survival rate was 50% with a median follow-up of 72 months. Over 20 clinical, radiological and laboratory parameters have been studied, including variables reported to be important indicators of prognosis in previous series, and these variables have been subjected to univariate and multivariate analysis. Attainment of complete remission (CR) was the most important predictor of overall survival, low serum lactate dehydrogenase (LDH), limited stage disease and a high serum albumin were also independently associated with prolonged survival in multivariate analysis. After removing remission status from the model, Ann Arbor clinical stage became the most significant pre-treatment prognostic indicator. Sixty-five per cent of patients achieved CR, and a discriminant analysis showed that failure to attain CR was associated with advanced stage disease, constitutional symptoms, increasing patient age, a low serum albumin and the presence of bulk disease. Advanced clinical stage and an elevated serum LDH predicted independently for a poor relapse-free survival, and reduced overall survival following CR. There was no significant correlation between histological subtype in the Kiel classification and prognosis. This study confirms the prognostic significance of remission status and Ann Arbor clinical stage, and illustrates additional factors including serum levels of albumin and LDH, which serve to enhance the pre-treatment prognostic evaluation of patients with unfavourable histology NHL
Collaborative Musical Expression and Creativity Among Academics: When Intellectualism Meets Twelve Bar Blues
The Professors are a blues, rock, and sometime heavy metal band made up of communication professors from a number of New Jersey schools. Formed in 1995, the band has played in clubs in New York City as well as a number of academic venues, including the annual conference of the International Communication Association in Chicago in 1996 and the annual conference of the National Communication Association in New York City in 1998. The Professors have been featured in both local and national press, including the Chronicle of Higher Education. When we learned of the call for papers for this special issue of the American Communication Journal addressing the creative endeavors of Communication scholars beyond their regular research agendas, we were delighted to have the opportunity to reflect upon the place of musical creativity within our lives as working academics. What follows in this paper are the thoughts of a number of band members, past and present, who trace the relationship of the musical, the creative, and the intellectual in terms of their own personal histories and academic interests
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