390 research outputs found
On a problem posed by Bjorn Poonen
Bjorn Poonen asked whether there exists a polynomial giving a surjection
. We answer this question in the
negative, conditional on a conjecture of Vojta. More precisely, we show that if
such a function exists, there is a family of open surfaces with dense integral
points despite the surfaces being of log general type.Comment: 11 pages, 1 figure. Comments welcome
3-Torsion Subgroups of Jacobians of Plane Quartics
In this paper we give an algorithm to find the 3-torsion subgroup of the
Jacobian of a smooth plane quartic curve. We describe torsion points in
terms of cubics which triply intersect the curve, and use this to define a
system of equations whose solution set corresponds to the coefficients of these
cubics. We compute the points of this zero-dimensional, degree scheme
first by approximation, using homotopy continuation and Newton-Raphson, and
then using lattice reduction or continued fractions to obtain accurate
expressions for these points. We describe how the Galois structure of the field
of definition of the -torsion subgroup can be used to compute local
conductor exponents, including at .Comment: 18 pages, comments welcome
Mammalian cell-driven polymerisation of pyrrole
A model cancer cell line was used to initiate polymerisation of pyrrole to form the conducting material polypyrrole. The polymerisation was shown to occur via cytosolic exudates rather than via membrane redox sites which normally control the oxidation state of iron as ferricyanide or ferrocyanide.. The data demonstrate for the first time that mammalian cells can be used to initiate synthesis of conducting polymers, and suggest a possible route to detection of cell damage and/or transcellular processes via an inâsitu and amplifiable signal generation
Dealing with isolation using online morning huddles for university lecturers during physical distancing by COVID-19 field notes
Isolation can affect our well-being negatively. To prevent the spread of the infection COVID-19, many workers, including university lecturers, are required to work from home. In order to maintain high levels of well-being and team cohesion, academics at the University of Derby Online Learning initiated a virtual huddle to briefly socialise and check on their colleaguesâ well-being every morning. This piece of field notes reports the context (COVID-19 in the United Kingdom), the details of this morning socialization, the first-hand experience of attending this huddle, and possible applications. Perceived positive impacts of our huddles include better well-being, cultivating compassion in team culture, and enhanced team cohesion. These advantages can be also useful in student supervision, wider socialization with colleagues to counter the silo mentality, and other occupational sectors. Our field notes will be helpful for lecturers and other types of employees who work collaboratively yet in isolation during this uncertain and challenging time of crisis.N/
Operational Radiology Recovery in Academic Radiology Departments After the COVID-19 Pandemic: Moving Toward Normalcy
This article presents a current snapshot in time, describing how radiology departments around the country are planning recovery from the baseline of the coronavirus disease 2019 pandemic, with a focus on different domains of recovery such as managing appointment availability, patient safety and workflow changes, and operational data and analytics. An e-mail survey was sent through the Society of Chairs of Academic Radiology Departments list server to 114 academic radiology departments. On the basis of data reported by the 38 survey respondents, best practices and shared experience are described for three key areas: (1) planning for recovery, (2) creating a new normal, and (3) measuring and forecasting. Radiology practices should be aware of the common approaches and preparations academic radiology departments have taken to reopening imaging in the post-coronavirus disease 2019 world. This should all be done when maintaining a safe and patient-centric environment and preparing to minimize the impact of future outbreaks or pandemics
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Design of a Standard Speed, Revolving Field Type, Three Phase Alternator
The designing of electrical machinery is fully
as essential to the thorough understanding of power
equipment and apparatus, as is the taking of a laboratory
testing course. One learns the relationship
of the different parts, the methods of computing
their dimensions, and the predetermination of outputs,
efficiencies, etc. and thus is enabled to better
judge the favorable and unfavorable qualities--
the good and bad points of generators, motors and
other appliances used in the great field of electrical
engineering. The realization of the training
value of such work; specially in alternating
current design led the writers of this thesis to
select the subject chosen
Sedimentology and stratigraphy of the Kellaways Sand Member (Lower Callovian), Burythorpe, North Yorkshire, UK
In the Burythorpe area of the Howardian Hills, located on the northern margin of the Market Weighton High, the Callovian succession is represented only by Lower Callovian sediments. These belong to the Kellaways Sand Member (Kellaways Formation), up to 12â
m thick, but thinning southwards to 5â
m. This contrasts with the more complete Callovian succession (Osgodby Formation) on the Yorkshire coast (Cleveland Basin) which is up to 32.5â
m thick. At Burythorpe Quarry the Kellaways Sand Member has yielded palynomorphs and ammonites confirming an Early Callovian (Koenigi Zone) age with depositional hiatuses above and below. The sequence consists of a yellow-white, poorly cemented, fine-to medium grained, unimodal uncemented sand (moulding sand) with sparse grey clay beds and laminae, in marked contrast to the broadly coeval Red Cliff Rock Member (Osgodby Formation) of the Cleveland Basin.
The depositional environment is interpreted as a tidally influenced shallow sea on the margin of the Market Weighton High, in a shallow sub-tidal regime, similar to the sub-tidal sand-mud lithofacies in the Heligoland region of the present-day North Sea. Winnowing of the sand in highly mobile substrate resulted in a unimodal grain size, lack of impurities, and sparse shelly- and ichnofaunas. However, during quieter water phases, grey clay laminae were deposited at the base of channels, allowing colonization of the substrate by burrowing ichnofauna and deposition of palynomorphs. Sparse, calcite-cemented tabular beds with a benthic shelly fauna, ammonites, Planolites burrows and mudstone rip-up clasts are interpreted as the deposits of periodic storm events. The marked local variation in thickness of the Kellaways Sand Member in the Howardian Hills is probably due to synsedimentary eastâwest-trending faulting related to the Flamborough Fault Zone
Selected In-Season Nutritional Strategies to Enhance Recovery for Team Sport Athletes: A Practical Overview
Team sport athletes face a variety of nutritional challenges related to recovery during the competitive season. The purpose of this article is to review nutrition strategies related to muscle regeneration, glycogen restoration, fatigue, physical and immune health, and preparation for subsequent training bouts and competitions. Given the limited opportunities to recover between training bouts and games throughout the competitive season, athletes must be deliberate in their recovery strategy. Foundational components of recovery related to protein, carbohydrates, and fluid have been extensively reviewed and accepted. Micronutrients and supplements that may be efficacious for promoting recovery include vitamin D, omega-3 polyunsaturated fatty acids, creatine, collagen/vitamin C, and antioxidants. Curcumin and bromelain may also provide a recovery benefit during the competitive season but future research is warranted prior to incorporating supplemental dosages into the athlete's diet. Air travel poses nutritional challenges related to nutrient timing and quality. Incorporating strategies to consume efficacious micronutrients and ingredients is necessary to support athlete recovery in season
Mechanistic insight into heterogeneity of trans-plasma membrane electron transport in cancer cell types
Trans-plasma membrane electron transfer (tMPET) is a process by which reducing equivalents, either electrons or reductants like ascorbic acid, are exported to the extracellular environment by the cell. TPMET is involved in a number of physiological process and has been hypothesised to play a role in the redox regulation of cancer metabolism. Here, we use a new electrochemical assay to elucidate the âpreferenceâ of cancer cells for different trans tPMET systems. This aids in proving a biochemical framework for the understanding of tPMET role, and for the development of novel tPMET-targeting therapeutics. We have delineated the mechanism of tPMET in 3 lung cancer cell models to show that the external electron transfer is orchestrated by ascorbate mediated shuttling via tPMET. In addition, the cells employ a different, non-shuttling-based mechanism based on direct electron transfer via Dcytb. Results from our investigations indicate that tPMETs are used differently, depending on the cell type. The data generated indicates that tPMETs may play a fundamental role in facilitation of energy reprogramming in malignant cells, whereby tPMETs are utilised to supply the necessary energy requirement when mitochondrial stress occurs. Our findings instruct a deeper understanding of tPMET systems, and show how different cancer cells may preferentially use distinguishable tPMET systems for cellular electron transfer processes
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