Extensional flow of a compressible viscous fluid

We derive reduced models for extrusion problems where it is necessary to account for fluid compressibility. We consider the two-dimensional extensional flow of a compressible viscous fluid and discuss two specific applications: weakly compressible fluids and bubbly liquid-gas mixtures that behave as a single compressible fluid. The mathematical model we present consists of equations for conservation of mass, conservation of momentum and a closure relationship between the pressure and density. The most substantial differences between compressible extrusion problems is in the closure relationship. By integrating the conservation equations across the fluid cross-section and exploiting a slender aspect ratio, we derive reduced equations for conservation of mass and conservation of momentum in the direction of flow. The reduced system of equations relating cross-sectionally averaged quantities is closed by a relationship between the averaged pressure and density, which will differ substantially depending on the application. We demonstrate the utility of a reduced model for both the weakly compressible fluid and bubbly mixture applications; namely, in providing valuable quantitative insights without needing to solve a complicated free-boundary problem

LONTalk as a Standard Protocol For Underwater Sensor Platforms

Proceedings IEEE, Oceans 97, Halifax, Oct. 1997 IEEE CD-ROM 0-7803-4111-

Structural Geomety of Thrust Faulting in the Summerfield and Leflore SE 7.5-Minute Quadrangles, Leflore County, SE Oklahoma

Boone Pickens School of Geolog

The frequency, nature and impact of GP-assessed avoidable delays in a population-based cohort of cancer patients

Background: There is a growing emphasis on the speed of diagnosis as an aspect of cancer prognosis. While epidemiological data in the last decade have quantified diagnostic timeliness and its variation, whether and how often prolonged diagnostic intervals can be considered avoidable is unknown. // Methods: We used data from the English National Cancer Diagnosis Audit (NCDA) on 17,042 patients diagnosed with cancer in 2014. Participating primary care physicians were asked to identify delays in diagnosis that they deemed avoidable, together with the ‘setting’ of the avoidable delay and key attributable factors. We used descriptive analysis and regression frameworks to assess validity and examine variation in the frequency and nature of avoidable delays. // Results: Among 14,259 patients, 24% were deemed to have had an avoidable delay to their diagnosis. Patients with a reported avoidable delay had a longer median diagnostic interval (92 days) than those without (30 days). Of all avoidable delays, 13% were deemed to have occurred pre-consultation, 49% within primary care, and 38% within secondary care. Avoidable delays were mostly attributed to the test request/performance phase (25%). Multimorbidity was associated with greater odds of avoidable delay (OR for 3+ vs no comorbidity: 1.43 (95% CI 1.25–1.63)), with heterogeneous associations with cancer site. // Conclusion: We have shown that GP-identified instances of avoidable delay have construct validity. Whilst the causes of avoidable diagnostic delays are multi-factorial and occur in different settings and phases of the diagnostic process, their analysis can guide improvement initiatives and enable the examination of any prognostic implications

Investment in Cellulosic Biofuel Refineries: Do Waivable Biofuel Mandates Matter?

We develop a conceptual model to study the impact of mandate policies on stimulating investment in cellulosic biofuel refineries. In a two-period framework, we compare the first-period investment level (FIL) under three scenarios: laissez-faire, non-waivable mandate (NWM) policy, and waivable mandate (WM) policy. Results show that when plant-level marginal costs are increasing then both NWM policy and WM policy may stimulate FIL. The WM policy has a smaller impact than does the NWM policy. When the plant-level marginal costs are constants, however, WM policy does not increase FIL but does increase the expected profit of more efficient investors

Morbidity and measures of the diagnostic process in primary care for patients subsequently diagnosed with cancer

Background: There is uncertainty regarding how pre-existing conditions (morbidities) may influence the primary care investigation and management of individuals subsequently diagnosed with cancer. / Methods: We identified morbidities using information from both primary and secondary care records among 11,716 patients included in the English National Cancer Diagnosis Audit (NCDA) 2014. We examined variation in 5 measures of the diagnostic process (the primary care interval, diagnostic interval, number of pre-referral consultations, use of primary care-led investigations, and referral type) by both primary care- and hospital records-derived measures of morbidity. / Results: Morbidity prevalence recorded before cancer diagnosis was almost threefold greater using the primary care (75%) vs secondary care-derived measure (28%). After adjustment, there was limited variation in the primary care interval and the number of pre-referral consultations by either definition of morbidity. Patients with more severe morbidities were less likely to have had a primary care-led investigation before cancer diagnosis compared with those without any morbidity (adjusted odds ratio, OR [95% confidence interval]: 0.72 [0.60–0.86] for Charlson score 3+ vs 0; joint P 1.00–1.41], respectively), and more likely to receive an emergency referral (aOR: 1.60 [1.26–2.02] and 1.61 [1.26–2.06], respectively). / Conclusion: Among cancer cases with up to 2 morbidities, there was no evidence of differences in diagnostic processes and intervals in primary care but higher morbidity burden was associated with longer time to diagnosis and higher likelihood of emergency referral