Topographically forced long waves on a sheared coastal current. Part 1. The weakly nonlinear response

The flow of a constant-vorticity current past coastal topography is investigated in the long-wave weakly nonlinear limit. In contrast to other near-critical weakly nonlinear systems this problem does not exhibit hydraulically controlled solutions. It is shown that near criticality the evolution of the vorticity interface is governed by a forced BDA (Benjamin-Davis-Acrivos) equation. The solutions of this equation are discussed and two distinct near-critical flow regimes are identified. Owing to the non-local nature of the forcing, the first of these regimes is characterized by quasi-steady solutions controlled at the topography with some blocking of the upstream rotational fluid, while in the second regime steady nonlinear wavetrains form downstream of the obstacle with no upstream influence. In the hydraulic limit the velocity band for both of these critical regimes approaches zero

Topographically forced long waves on a sheared coastal current. Part 2. Finite amplitude waves

This paper analyses the finite-amplitude flow of a constant-vorticity current past coastal topography in the long-wave limit. A forced finite-amplitude long-wave equation is derived to describe the evolution of the vorticity interface. An analysis of this equation shows that three distinct near-critical regimes occur. In the first the upstream flow is restricted, with overturning of the vorticity interface for sufficiently large topography. In the second quasi-steady nonlinear waves form downstream of the topography with weak upstream influence. In the third regime the upstream rotational fluid is partially blocked. Blocking and overturning are enhanced at headlands with steep rear faces and decreased at headlands with steep forward faces. For certain parameter values both overturning and partially blocked solutions are possible and the long-time evolution is critically dependent on the initial conditions. The reduction of the problem to a one-dimensional nonlinear wave equation allows solutions to be followed to much longer times and parameter space to be explored more finely than in the related pioneering contour-dynamical integrations of Stern (1991)

Harold Clarke Johnson Papers - Accession 575

The Harold Clarke Johnson Papers mainly pertains to York County history and includes deeds, titles, bonds, county expenses, tax, and treasurer reports, and annual reports of the treasurer of York County to the state Superintendent of Education, and of the York County Treasurer. These records relate to the financial affairs of York County between 1889 and 1910 and offers a great insight into the finances of the county during that timeframe. The material was collected by the York (South Carolina) Historical American Bicentennial. Of special interest, is a brief history of an 1820 map of York County, written by Harold Clarke, Sr. (1913-1993), member of York (South Carolina) Bicentennial Committee, and a historical sketch of York County (1976) prepared by the York County Historical Commission.https://digitalcommons.winthrop.edu/manuscriptcollection_findingaids/1689/thumbnail.jp

Self-expanding metal stent placement for oesophageal cancer without fluoroscopy is safe and effective

Background. Self-expanding metal stents (SEMS) are widely used to palliate patients with oesophageal cancer. Placement is usually done under endoscopic and fluoroscopic guidance. We have developed an exclusively endoscopic technique to deploy these stents. This article documents the technique and periprocedural experience.Patients and methods. All patients who had SEMS placement for oesophageal cancer at Grey’s Hospital, Pietermaritzburg, South Africa, over a 5-year period (2007 - 2011) were reviewed. Stenting was performed without radiological guidance using the technique documented in this article. At endoscopy, the oesophageal lesion was identified, dilated over a guidewire if necessary, and a partially covered stent was passed over the wire and positioned and deployed under direct vision. Data were captured from completed procedure forms and included demographics, tumour length, the presence of fistulas, stent size and immediate complications.Results. A total of 480 SEMS were inserted, involving 453 patients, of whom 43 required repeat stenting. There were 185 female patients (40.8%) and 268 male patients (59.2%). The mean age was 60 years (range 38 - 101). There were 432 black patients (95.4%), 15 white patients (3.3%) and 6 Indian patients (1.3%). The reasons for palliative stenting were distributed as follows: age >70 years n=95 patients, tumour >8 cm n=142, tracheo-oesophageal fistula (TOF) n=29, and unspecified n=170. One patient refused surgery, and one stent was placed for a post-oesophagectomy leak. Repeat stenting was for stent migration (n=15), tumour overgrowth (n=26) and a blocked stent and a stricture (n=1 each). Complications were recorded in six cases (1.3%): iatrogenic TOF (n=2), false tracts (n=3) and perforation (n=1). All six were nevertheless successfully stented. There was no periprocedural mortality.Conclusion. The endoscopic placement technique described is a viable and safe option with a low periprocedural complication rate. It is of particular use in situations of restricted access to fluoroscopic guidance

Dispersive effects in Rossby-wave hydraulics

This paper considers the role of long finite-amplitude Rossby waves in determining the evolution of how along a rapidly rotating channel with an uneven floor. The Rossby waves travel on a potential vorticity interface in a channel with a cross-channel step change in depth, where step position varies slowly along the channel. A nonlinear wave equation is derived describing the evolution of the potential vorticity interface. To leading order this is the hydraulic equation derived by Haynes, Johnson & Hurst (1993). Dispersion appears at the next order. Various solution regimes are identified. As well as slowly varying hydraulic solutions, two further types of steady solutions appear: approach-controlled flows and twin supercritical leaps. Both these solutions are characterized by leaps between supercritical branches of the hydraulic function. It is shown how the position and size of these 'supercritical leaps' can be determined within the context of hydraulic theory. To fully resolve the internal structure of these leaps dispersive effects must be included and leaps are shown to correspond to kink soliton solutions of the steady unforced problem. It is also shown that increasing dispersion (decreasing topographic length scale) causes the loss of the subcritical solution branch in some subcritical flows. The only candidate for a steady solution in these regimes is then an approach-controlled flow. Integrations of initial value problems show that in general flows evolve towards the dispersive form of the solution predicted by hydraulic theory, at least near the topographic perturbation. However, in those subcritical hows where sufficiently large dispersion causes the subcritical branch to disappear, unsteady integrations evolve to approach-controlled flows even when the dispersion is sufficiently small that the subcritical branch still exists

Mapping of Technological Opportunities-Labyrinth Seal Example

All technological systems evolve based on evolutionary sequences that have repeated throughout history and can be abstracted from the history of technology and patents. These evolutionary sequences represent objective patterns and provide considerable insights that can be used to proactively model future seal concepts. This presentation provides an overview of how to map seal technology into the future using a labyrinth seal example. The mapping process delivers functional descriptions of sequential changes in market/consumer demand, from today s current paradigm to the next major paradigm shift. The future paradigm is developed according to a simple formula: the future paradigm is free of all flaws associated with the current paradigm; it is as far into the future as we can see. Although revolutionary, the vision of the future paradigm is typically not immediately or completely realizable nor is it normally seen as practical. There are several reasons that prevent immediate and complete practical application, such as: 1) Some of the required technological or business resources and knowledge not being available; 2) Availability of other technological or business resources are limited; and/or 3) Some necessary knowledge has not been completely developed. These factors tend to drive the Total Cost of Ownership or Utilization out of an acceptable range and revealing the reasons for the high Total Cost of Ownership or Utilization which provides a clear understanding of research opportunities essential for future developments and defines the current limits of the immediately achievable improvements. The typical roots of high Total Cost of Ownership or Utilization lie in the limited availability or even the absence of essential resources and knowledge necessary for its realization. In order to overcome this obstacle, step-by-step modification of the current paradigm is pursued to evolve from the current situation toward the ideal future, i.e., evolution rather than revolution. A key point is that evolutionary stages are mapped to show step-by-step evolution from the current paradigm to the next major paradigm

A Genome-scale CRISPR Screen Identifies the ERBB and mTOR Signaling Networks as Key Determinants of Response to PI3K Inhibition in Pancreatic Cancer.

KRAS mutation is a key driver of pancreatic cancer and PI3K pathway activity is an additional requirement for Kras-induced tumorigenesis. Clinical trials of PI3K pathway inhibitors in pancreatic cancer have shown limited responses. Understanding the molecular basis for this lack of efficacy may direct future treatment strategies with emerging PI3K inhibitors. We sought new therapeutic approaches that synergize with PI3K inhibitors through pooled CRISPR modifier genetic screening and a drug combination screen. ERBB family receptor tyrosine kinase signaling and mTOR signaling were key modifiers of sensitivity to alpelisib and pictilisib. Inhibition of the ERBB family or mTOR was synergistic with PI3K inhibition in spheroid, stromal cocultures. Near-complete loss of ribosomal S6 phosphorylation was associated with synergy. Genetic alterations in the ERBB-PI3K signaling axis were associated with decreased survival of patients with pancreatic cancer. Suppression of the PI3K/mTOR axis is potentiated by dual PI3K and ERBB family or mTOR inhibition. Surprisingly, despite the presence of oncogenic KRAS, thought to bestow independence from receptor tyrosine kinase signaling, inhibition of the ERBB family blocks downstream pathway activation and synergizes with PI3K inhibitors. Further exploration of these therapeutic combinations is warranted for the treatment of pancreatic cancer

A national survey assessing public readiness for digital health strategies against COVID-19 within the United Kingdom

There is concern that digital public health initiatives used in the management of COVID-19 may marginalise certain population groups. There is an overlap between the demographics of groups at risk of digital exclusion (older, lower social grade, low educational attainment and ethnic minorities) and those who are vulnerable to poorer health outcomes from SARS-CoV-2. In this national survey study (n=2040), we assessed how the UK population; particularly these overlapping groups, reported their preparedness for digital health strategies. We report, with respect to using digital information to make health decisions, that those over 60 are less comfortable (net comfort: 57%) than those between 18-39 (net comfort: 78%) and lower social grades are less comfortable (net comfort: 63%) than higher social grades (net comfort: 75%). With respect to a preference for digital over non-digital sources in seeking COVID-19 health information, those over 60 (net preference: 21%) are less inclined than those between 18-39 (net preference: 60%) and those of low educational attainment (net preference: 30%) are less inclined than those of high educational attainment (net preference: 52%). Lastly, with respect to distinguishing reliable digital COVID-19 information, lower social grades (net confidence: 55%) are less confident than higher social grades (net confidence: 68%) and those of low educational attainment (net confidence: 51%) are less confident than those of high educational attainment (net confidence: 71%). All reported differences are statistically significant (p<0.01) following multivariate regression modelling. This study suggests that digital public health approaches to COVID-19 have the potential to marginalise groups who are concurrently at risk of digital exclusion and poor health outcomes from SARS-CoV-2

Low‐cost tools mitigate climate change during reproduction in an endangered marine ectotherm

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordData Availability Statement: Data available via the Dryad Digital Repository https://doi.org/10.5061/dryad.3r2280gfq. (Clarke et al., 2021)The impacts of anthropogenic climate change will be most dramatic for species that live in narrow thermal niches, such as reptiles. Given the imminent threat to biodiversity, and that actions to reduce carbon emissions are not yet sufficient, it is important that a sound evidence base of potential mitigation options is available for conservation managers. Successful incubation and production of male sea turtle hatchlings is threatened by increased global temperatures (sex is determined by the temperature at which eggs incubate). Here we test two conservation tools to reduce incubation temperatures: clutch splitting and clutch shading, on a nesting loggerhead turtle (Caretta caretta) population in the Eastern Atlantic Ocean. During the thermosensitive period of incubation, split and shaded clutches were both 1.00 ˚C cooler than control nests. Clutch splitting (mean: 45 eggs) reduced nest temperatures by reducing metabolic heating during incubation compared to controls (mean: 92 eggs). Modelled primary sex ratios differed between nest treatments, with 1.50 % (± 6 % S.E.) females produced in shaded nests, 45.00 % (± 7 % S.E.) females in split nests and 69.00 % (± 6% S.E.) females in controls. Neither treatment affected hatchling size, success, mass or vigour. When clutch splitting was repeated two years later, hatch success was higher in split clutches compared to controls. Synthesis and Applications: Clutch splitting and clutch shading successfully altered the thermal profile of incubating turtle nests. When there is sufficient knowledge to better understand the effects of intervention on fundamental population demographics, they will be useful for reducing incubation temperatures in sea turtle nests, potentially increasing nest survival and male hatchling production. The effect of clutch splitting in reducing nest temperature was lower relative to clutch shading, but requires significantly less funding, materials and specialist skill, key factors for management of turtle rookeries that are often in remote, resource‐limited areas.Worldwide Fund for NatureWAVE Foundation of Newport Aquariu