741 research outputs found
The legacy of uncertainty
An historical account is given of the circumstances whereby the uncertainty relations were introduced into physics by Heisenberg. The criticisms of QED on measurement-theoretical grounds by Landau and Peierls are then discussed, as well as the response to them by Bohr and Rosenfeld. Finally, some examples are given of how the new freedom to advance radical proposals, in part the result of the revolution brought about by 'uncertainty,' was implemented in dealing with the new phenomena encountered in elementary particle physics in the 1930's
Measuring Positive Youth Development at Summer Camp: Problem Solving and Camp Connectedness
While research on summer camps has generally supported the benefits of organized camping for youth, increasing pressure exists for camps to document outcomes to stakeholders and to base their practices on evidence. This paper discusses the theoretical and empirical development of two measures relevant to these needs: Problem Solving Confidence and Camp Connectedness. The process of scale development included reviewing conceptual and theoretical literature as it related to camp settings. Items based on the relevant content domains were then generated, reviewed by experts, and pilot tested with 557 campers. Evidence from this pilot study suggests that both measures may be reliable and valid measures of their respective constructs. Implications for use and ties to the extant literature are discussed
Numerical investigation into the combustion behavior of an inlet-fueled thermal-compression-like scramjet
A numerical study on the combustion behavior of an inlet-fueled three-dimensional nonuniform-compression scramjet is presented. This paper is an extension to previous work on the combustion processes in a premixed three-dimensional nonuniform-compression scramjet, where thermal compression was shown to enhance combustion. This paper demonstrates how thermal compression can be used in a generic scramjet configuration with a realistic fuel-injection method to enhance performance at high flight Mach numbers. Such a scramjet offers an extra degree of freedom in the design process of fixed-geometry scramjets that must operate over a range of flight Mach numbers. In this study, how the combustion processes are affected is investigated, with the added realism of inlet porthole fuel injection. Ignition is established from within a shock-induced boundary-layer separation at the entrance to the combustor. Radicals that form upstream of the combustor within the inlet, from the injection method, enhance combustion. Coupling of the inlet-induced spanwise gradients and thermal compression improves combustion. The results highlight that, although the fuel-injection method imparts local changes to the flow structures, the global flow behavior does not change compared to previous premixed results. This combustion behavior will be reproduced when using other fueling methods that deliver partially premixed fuel and air to the combustor entrance
NRG Oncology-Radiation Therapy Oncology Group Study 1014: 1-Year Toxicity Report From a Phase 2 Study of Repeat Breast-Preserving Surgery and 3-Dimensional Conformal Partial-Breast Reirradiation for In-Breast Recurrence.
PURPOSE: To determine the associated toxicity, tolerance, and safety of partial-breast reirradiation.
METHODS AND MATERIALS: Eligibility criteria included in-breast recurrence occurring \u3e1 year after whole-breast irradiation, \u3c3 \u3ecm, unifocal, and resected with negative margins. Partial-breast reirradiation was targeted to the surgical cavity plus 1.5 cm; a prescription dose of 45 Gy in 1.5 Gy twice daily for 30 treatments was used. The primary objective was to evaluate the rate of grade ā„3 treatment-related skin, fibrosis, and/or breast pain adverse events (AEs), occurring ā¤1 year from re-treatment completion. A rate of ā„13% for these AEs in a cohort of 55 patients was determined to be unacceptable (86% power, 1-sided Ī± = 0.07).
RESULTS: Between 2010 and 2013, 65 patients were accrued, and the first 55 eligible and with 1 year follow-up were analyzed. Median age was 68 years. Twenty-two patients had ductal carcinoma in situ, and 33 had invasive disease: 19 ā¤1 cm, 13 \u3e1 to ā¤2 cm, and 1 \u3e2 cm. All patients were clinically node negative. Systemic therapy was delivered in 51%. All treatment plans underwent quality review for contouring accuracy and dosimetric compliance. All treatment plans scored acceptable for tumor volume contouring and tumor volume dose-volume analysis. Only 4 (7%) scored unacceptable for organs at risk contouring and organs at risk dose-volume analysis. Treatment-related skin, fibrosis, and/or breast pain AEs were recorded as grade 1 in 64% and grade 2 in 7%, with only 1 (
CONCLUSION: Partial-breast reirradiation with 3-dimensional conformal radiation therapy after second lumpectomy for patients experiencing in-breast failures after whole-breast irradiation is safe and feasible, with acceptable treatment quality achieved. Skin, fibrosis, and breast pain toxicity was acceptable, and grade 3 toxicity was rare
Modelling cross-reactivity and memory in the cellular adaptive immune response to influenza infection in the host
The cellular adaptive immune response plays a key role in resolving influenza
infection. Experiments where individuals are successively infected with
different strains within a short timeframe provide insight into the underlying
viral dynamics and the role of a cross-reactive immune response in resolving an
acute infection. We construct a mathematical model of within-host influenza
viral dynamics including three possible factors which determine the strength of
the cross-reactive cellular adaptive immune response: the initial naive T cell
number, the avidity of the interaction between T cells and the epitopes
presented by infected cells, and the epitope abundance per infected cell. Our
model explains the experimentally observed shortening of a second infection
when cross-reactivity is present, and shows that memory in the cellular
adaptive immune response is necessary to protect against a second infection.Comment: 35 pages, 12 figure
Safety and Efficacy of Long-Term Use of Extended Release Cornstarch Therapy for Glycogen Storage Disease Types 0, III, VI, and IX
Background: Impaired glycogen release with fasting results in hypoglycemia in the glycogen storage diseases. A waxy-maize extended release cornstarch was introduced in the United States in 2012 to maintain glucose concentrations during the overnight period, but no studies have assessed the long-term safety and efficacy of this product in the ketotic forms of GSD.Objective: To assess long-term safety and efficacy of modified cornstarch in patients with ketotic forms of GSD.Design: An open label overnight trial of extended release cornstarch was performed. Subjects who had a successful trial (defined as optimal metabolic control lasting 2 or more hours more than with traditional cornstarch) were given the option of continuing into the long-term observational phase. Participants were assessed biochemically at baseline and after 12 months.Results: A total of 16 subjects participated in the open label trial. Efficacy was demonstrated in 100% of the subjects with GSD 0, III, VI, and IX. Of the patients who entered the longitudinal phase, long-term data are available for all subjects. The mean duration of overnight fasting on traditional cornstarch prior to the study for the cohort was 4.9 hours and 9.6 hours on the extended release cornstarch (P < 0.001). All laboratory markers of metabolic control have remained stable in the chronically treated patients.Conclusion: Extended release cornstarch dramatically prolongs the overnight fast duration, maximizes safety from hypoglycemic events, reduces the possibility of sleep deprivation, and improves the quality of life of patients by eliminating the need to awaken without fail for middle of the night therapy without sacrificing metabolic control
New HIV cases diagnosed though opt-out testing in hyperacute stroke: a call to amend national guidelines
Facile purification of milligram to gram quantities of condensed tannins according to mean degree of polymerization and flavan-3-ol subunit composition
Unambiguous investigation of condensed tannin (CT) structure-activity relationships in biological systems requires well-characterized, high-purity CTs. Sephadex LH-20 and Toyopearl HW-50F resins were compared for separating CTs from acetone/water extracts and column fractions analyzed for flavan-3-ol subunits, mean degree of polymerization (mDP) and purity. Toyopearl HW-50F generated fractions with higher mDP values and better separation of procyanidins (PC) and prodelphinidins (PD) but required a pre-purification step, more time for large scale purifications and gave poorer recoveries. Therefore, two gradient elution schemes were developed for CT purification on Sephadex LH-20 providing 146 - 2000 mg/fraction. Fractions were analyzed by thiolysis and NMR spectroscopy. In general, PC/PD ratios decreased and mDP increased during elution. 1H NMR spectroscopy served as a rapid screening tool to qualitatively determine CT enrichment and carbohydrate impurities present, guiding fractionation towards re-purification or 1H-13C HSQC NMR spectroscopy and thiolysis. These protocols provide options for preparing highly pure CT samples
SaferWheels study on powered two-wheeler and bicycle accidents in the EU - Annex 6 case summaries
SaferWheels study on powered two-wheeler and bicycle accidents in the EU - Annex 6 case summarie
From the cell membrane to the nucleus: unearthing transport mechanisms for Dynein
Mutations in the motor protein cytoplasmic dynein have been found to cause Charcot-Marie-Tooth disease, spinal muscular atrophy, and severe intellectual disabilities in humans. In mouse models, neurodegeneration is observed. We sought to develop a novel model which could incorporate the effects of mutations on distance travelled and velocity. A mechanical model for the dynein mediated transport of endosomes is derived from first principles and solved numerically. The effects of variations in model parameter values are analysed to find those that have a significant impact on velocity and distance travelled. The model successfully describes the processivity of dynein and matches qualitatively the velocity profiles observed in experiments
- ā¦