1,564 research outputs found
Estimating Distributional Impacts of an Innovation Across Sectors in an Industry: A case study of the Australian wool industry
In this paper an approach that can be used to determine the distribution of a productivity gain on an industry is detailed. In particular, the model developed in this paper extends earlier evaluations by emphasising the crucial role of substitution between inputs across different participants in the supply chain. Crucial to any analysis of an industry are the estimates of the elasticity's of derived demand at each stage and how it changes, as the product is further refined. The wool industry is used to illustrate the effects of an innovation across sectors.Agribusiness, Production Economics,
Fragmentation with a Cut on Thrust: Predictions for B-factories
When high-energy single-hadron production takes place inside an identified
jet, there are important correlations between the fragmentation and phase-space
cuts. For example, when one-hadron yields are measured in on-resonance
B-factory data, a cut on the thrust event shape T is required to remove the
large b-quark contribution. This leads to a dijet final state restriction for
the light-quark fragmentation process. Here we complete our analysis of
unpolarized fragmentation of (light) quarks and gluons to a light hadron h with
energy fraction z in e+ e- -> dijet + h at the center-of-mass energy Q=10.58
GeV. In addition to the next-to-next-to-leading order resummation of logarithms
of 1-T, we include the next-to-leading order (NLO) nonsingular O(1-T)
contribution to the cross section, the resummation of threshold logarithms of
1-z, and the leading nonperturbative contribution to the soft function. Our
results for the correlations between fragmentation and the thrust cut are
presented in a way that can be directly tested against B-factory data. These
correlations are also observed in Pythia, but are surprisingly smaller at NLO.Comment: 10 pages + appendices, 13 figures, v2:updated discussion, journal
versio
Analysis of CareFirst\u27s Performance as a Charitable Not-for-Profit Health Insurance Company in the National Capital Area
The George Washington University School of Public Health and Health Services ( GWU ) and the Georgetown University Institute for Health Care Research and Policy ( GU )conducted this analysis on behalf of the DC Appleseed Center for Law and Justice in order to examine whether, in its operations and business practices, CareFirst BlueCross BlueShield ( CareFirst ) appears to be fulfilling its chartered mission for the National Capital Area. The study began as an analysis of the coverage and access implications for the region of a proposal made by CareFirst and WellPoint Health Networks, Inc. ( WellPoint ) to convert CareFirst to for-profit status and permit its acquisition by WellPoint for a price of $1.3 billion. Maryland\u27s Commissioner of Insurance rejected the proposal in March 2003. Upon the request of CareFirst and WellPoint, the insurance commissioners in the District of Columbia and Delaware suspended their review of the transaction
Early cell loss associated with mesenchymal stem cell cardiomyoplasty
Background: Human mesenchymal stem cells (hMSCs) show potential for therapeutic cellular cardiomyoplasty. However, a range of delivery methods, including direct intramyocardial injection, have resulted in poor engraftment in vivo. We used the in vivo rat heart model to study hMSC engraftment and retention in a normal beating heart. Materials and Methods: HMSCs transfected with green fluorescent protein were injected into the left ventricle (LV) of immunocompetent rats. Hearts were cryopreserved 30 minutes (Group A), 24 hours (Group B), and 5 days (Group C) post hMSC delivery. HMSC retention was estimated using confocal fluorescence microscopy and immunohistochemistry. Measured values were compared to projected GFP-positive cellular volumes. Immunohistochemical analyses probed for the presence of human cells with human prolyl hydroxylase beta (p4hβ) and an immune response with murine monocyte/macrophage antigen (CD68). Results: HMSC retention decreased significantly from 30 minutes to 5 days
(p<0.05). In Group A the projected GFP positive cellular volume of 31% correlated with measured values and was significantly greater than the 1% predicted cellular volume in Group C. Moreover, human p4hβ was detected in Groups A and B, and not in Group C. Conversely, CD68 was detected in Groups B and C and not in Group A. Conclusions: In immunocompetent rats, engraftment and retention of hMSCs delivered intramyocardially significantly declines over a five day period. The influx of monocytes/macrophages suggests an unfavorable micro-environment for exogenous stem cell survival, confirmed by the absence of human cells detected five days post injection
Chronic kidney disease: The distribution of health care dollars
Chronic kidney disease: The distribution of health care dollars.BackgroundThe cost of care for end-stage renal disease (ESRD) is known to be high. The factors responsible for higher ESRD cost develop during chronic kidney disease (CKD), where the data on distribution of cost are limited.MethodsThis retrospective cohort study of 1995 through 1998 incident dialysis patients was performed to study the distribution of costs during the 24 months prior to initiation of dialysis. Patient data were obtained from the Centers for Medicare and Medicaid Services (CMS). Patients who were Medicare eligible for at least 2 years prior to initiation of dialysis were included in the study. Financial data were obtained from Medicare Part A and Part B claims and inflationary adjustments were made. The study period was divided into four segments based on overall distribution of cost.ResultsThe mean age was 75 years, 51% were males, 73% were white, and 22% were black. Overall, patient comorbidity increased significantly during the study years. Cost showed a sharp increase in the last 6 months prior to initiation of dialysis. Hospitalization was the major component of cost throughout study period. Patients who initiated hemodialysis incurred a higher cost compared to patients who initiated other modes of kidney replacement therapy. Patients with diabetes or cardiovascular disease incurred higher cost compared to those who had no diabetes or cardiovascular disease, respectively.ConclusionThese data showed that hospitalization was the major component of the sharp increase in cost around the initiation of dialysis. Increased comorbidity was associated with higher cost. A focus on timely management of CKD may prevent future morbidity and costs
Treatment of malignant tumors of the skull base with multi-session radiosurgery
<p>Abstract</p> <p>Objective</p> <p>Malignant tumors that involve the skull base pose significant challenges to the clinician because of the proximity of critical neurovascular structures and limited effectiveness of surgical resection without major morbidity. The purpose of this study was to evaluate the efficacy and safety of multi-session radiosurgery in patients with malignancies of the skull base.</p> <p>Methods</p> <p>Clinical and radiographic data for 37 patients treated with image-guided, multi-session radiosurgery between January 2002 and December 2007 were reviewed retrospectively. Lesions were classified according to involvement with the bones of the base of the skull and proximity to the cranial nerves.</p> <p>Results</p> <p>Our cohort consisted of 37 patients. Six patients with follow-up periods less than four weeks were eliminated from statistical consideration, thus leaving the data from 31 patients to be analyzed. The median follow-up was 37 weeks. Ten patients (32%) were alive at the end of the follow-up period. At last follow-up, or the time of death from systemic disease, tumor regression or stable local disease was observed in 23 lesions, representing an overall tumor control rate of 74%. For the remainder of lesions, the median time to progression was 24 weeks. The median progression-free survival was 230 weeks. The median overall survival was 39 weeks. In the absence of tumor progression, there were no cranial nerve, brainstem or vascular complications referable specifically to CyberKnife<sup>® </sup>radiosurgery.</p> <p>Conclusion</p> <p>Our experience suggests that multi-session radiosurgery for the treatment of malignant skull base tumors is comparable to other radiosurgical techniques in progression-free survival, local tumor control, and adverse effects.</p
Attenuation and efficacy of human parainfluenza virus type 1 (HPIV1) vaccine candidates containing stabilized mutations in the P/C and L genes
<p>Abstract</p> <p>Background</p> <p>Two recombinant, live attenuated human parainfluenza virus type 1 (rHPIV1) mutant viruses have been developed, using a reverse genetics system, for evaluation as potential intranasal vaccine candidates. These rHPIV1 vaccine candidates have two non-temperature sensitive (non-<it>ts</it>) attenuating (<it>att</it>) mutations primarily in the P/C gene, namely C<sup>R84G</sup>HN<sup>T553A </sup>(two point mutations used together as a set) and C<sup>Δ170 </sup>(a short deletion mutation), and two <it>ts att </it>mutations in the L gene, namely L<sup>Y942A </sup>(a point mutation), and L<sup>Δ1710–11 </sup>(a short deletion), the last of which has not been previously described. The latter three mutations were specifically designed for increased genetic and phenotypic stability. These mutations were evaluated on the HPIV1 backbone, both individually and in combination, for attenuation, immunogenicity, and protective efficacy in African green monkeys (AGMs).</p> <p>Results</p> <p>The rHPIV1 mutant bearing the novel L<sup>Δ1710–11 </sup>mutation was highly <it>ts </it>and attenuated in AGMs and was immunogenic and efficacious against HPIV1 wt challenge. The rHPIV1-C<sup>R84G/Δ170</sup>HN<sup>T553A</sup>L<sup>Y942A </sup>and rHPIV1-C<sup>R84G/Δ170</sup>HN<sup>T553A</sup>L<sup>Δ1710–11 </sup>vaccine candidates were highly <it>ts</it>, with shut-off temperatures of 38°C and 35°C, respectively, and were highly attenuated in AGMs. Immunization with rHPIV1-C<sup>R84G/Δ170</sup>HN<sup>T553A</sup>L<sup>Y942A </sup>protected against HPIV1 wt challenge in both the upper and lower respiratory tracts. In contrast, rHPIV1-C<sup>R84G/Δ170</sup>HN<sup>T553A</sup>L<sup>Δ1710–11 </sup>was not protective in AGMs due to over-attenuation, but it is expected to replicate more efficiently and be more immunogenic in the natural human host.</p> <p>Conclusion</p> <p>The rHPIV1-C<sup>R84G/Δ170</sup>HN<sup>T553A</sup>L<sup>Y942A </sup>and rHPIV1-C<sup>R84G/Δ170</sup>HN<sup>T553A</sup>L<sup>Δ1710–11 </sup>vaccine candidates are clearly highly attenuated in AGMs and clinical trials are planned to address safety and immunogenicity in humans.</p
A mouse model displays host and bacterial strain differences in Aerococcus urinae urinary tract infection
In recent years, the clinical significance of Aerococcus urinae has been increasingly recognized. A. urinae has been implicated in cases of urinary tract infection (UTI; acute cystitis and pyelonephritis) in both male and female patients, ranging from children to older adults. Aerococcus urinae can also be invasive, causing urosepsis, endocarditis, and musculoskeletal infections. Mechanisms of pathogenesis in A. urinae infections are poorly understood, largely due to the lack of an animal model system. In response to this gap, we developed a model of A. urinae urinary tract infection in mice. We compared A. urinae UTI in female C3H/HeN and C57BL/6 mice and compared four clinical isolates of A. urinae isolated from patients with UTI, urgency urinary incontinence, and overactive bladder. Our data demonstrate that host genetic background modulates A. urinae UTI. Female C57BL/6 female mice rapidly cleared the infection. Female C3H/HeN mice, which have inherent vesicoureteral reflux that flushes urine from the bladder up into the kidneys, were susceptible to prolonged bacteriuria. This result is consistent with the fact that A. urinae infections most frequently occur in patients with underlying urinary tract abnormalities or disorders that make them susceptible to bacterial infection. Unlike uropathogens such as E. coli, which cause infection and inflammation both of the bladder and kidneys in C3H/HeN mice, A. urinae displayed tropism for the kidney, persisting in kidney tissue even after clearance of bacteria from the bladder. Aerococcus urinae strains from different genetic clades displayed varying propensities to cause persistent kidney infection. Aerococcus urinae infected kidneys displayed histological inflammation, neutrophil recruitment and increased pro-inflammatory cytokines. These results set the stage for future research that interrogates host-pathogen interactions between A. urinae and the urinary tract
CyberKnife with Tumor Tracking: An Effective Treatment for High-Risk Surgical Patients with Stage I Non-Small Cell Lung Cancer
Published data suggests that wedge resection for stage I non-small cell lung cancer (NSCLC) is associated with improved overall survival compared to stereotactic body radiation therapy. We report CyberKnife outcomes for high-risk surgical patients with biopsy-proven stage I NSCLC. PET/CT imaging was completed for staging. Three-to-five gold fiducial markers were implanted in or near tumors to serve as targeting references. Gross tumor volumes (GTVs) were contoured using lung windows; the margins were expanded by 5 mm to establish the planning treatment volume (PTV). Treatment plans were designed using a mean of 156 pencil beams. Doses delivered to the PTV ranged from 42 to 60 Gy in three fractions. The 30 Gy isodose contour extended at least 1 cm from the GTV to eradicate microscopic disease. Treatments were delivered using the CyberKnife system with tumor tracking. Examination and PET/CT imaging occurred at 3 month follow-up intervals. Forty patients (median age 76) with a median maximum tumor diameter of 2.6 cm (range, 1.4–5.0 cm) and a mean post-bronchodilator percent predicted forced expiratory volume in 1 s (FEV1) of 57% (range, 21–111%) were treated. A median dose of 48 Gy was delivered to the PTV over 3–13 days (median, 7 days). The 30 Gy isodose contour extended a mean 1.9 cm from the GTV. At a median 44 months (range, 12–72 months) follow-up, the 3 year Kaplan–Meier locoregional control and overall survival estimates compare favorably with contemporary wedge resection outcomes at 91 and 75%, respectively. CyberKnife is an effective treatment approach for stage I NSCLC that is similar to wedge resection, eradicating tumors with 1–2 cm margins in order to preserve lung function. Prospective randomized trials comparing CyberKnife with wedge resection are necessary to confirm equivalence
Invariant classification and the generalised invariant formalism: conformally flat pure radiation metrics, with zero cosmological constant
Metrics obtained by integrating within the generalised invariant formalism
are structured around their intrinsic coordinates, and this considerably
simplifies their invariant classification and symmetry analysis. We illustrate
this by presenting a simple and transparent complete invariant classification
of the conformally flat pure radiation metrics (except plane waves) in such
intrinsic coordinates; in particular we confirm that the three apparently
non-redundant functions of one variable are genuinely non-redundant, and easily
identify the subclasses which admit a Killing and/or a homothetic Killing
vector. Most of our results agree with the earlier classification carried out
by Skea in the different Koutras-McIntosh coordinates, which required much more
involved calculations; but there are some subtle differences. Therefore, we
also rework the classification in the Koutras-McIntosh coordinates, and by
paying attention to some of the subtleties involving arbitrary functions, we
are able to obtain complete agreement with the results obtained in intrinsic
coordinates. In particular, we have corrected and completed statements and
results by Edgar and Vickers, and by Skea, about the orders of Cartan
invariants at which particular information becomes available.Comment: Extended version of GRG publication, with some typos etc correcte
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