A few years ago S-H Kim investigated some problems at the boundary of number theory, optimization, and geometry. One question regarded an optimal packing of certain “triangular oval” planar curves ...and another looked at some related transformations of ℝ2 to ℝ2. These were investigated primarily using tools from calculus but it turns out that computational algebra methods may instead be employed to particular advantage. Moreover, generalizations that are beyond the reach of such methods are still amenable to hybrid approaches using numeric and symbolic methods in tandem. We introduce some of the specific problems and generalizations, and show by detailed example how such techniques may be implemented and deployed.
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FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Due to sampling restrictions in the analysis of cultural heritage materials, non-destructive approaches are intensively sought for. While NIR spectrometry has rarely been used for this purpose due to ...the complexity of the spectra, chemometric methods can be used to extract the necessary information. For the purpose of determination of mechanical properties of historical paper, partial least squares approach was used and it is shown that tensile strength, and tensile strength after folding, can be estimated based on NIR spectra. As the mechanical properties of paper-based objects define their accessibility, a new dispersive portable instrument was built, which will enable us to rapidly survey the condition of library and archival collections.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
An efficient and rapid protocol has been developed for extracting ginkgolides and bilobalide (terpene trilactones) from Ginkgo biloba leaves. The procedure takes advantage of the extraordinary ...stability of the terpene trilactone structure to a variety of chemical treatments, especially oxidation, despite the presence of multiple oxygen functions. The protocol involves boiling the aqueous extract of leaves with dilute hydrogen peroxide, extraction with ethyl acetate, washing with basic solutions, and charcoal filtration to yield an off-white powder, terpene trilactone content 60−70%. It is likely that the hydrogen peroxide treatment degrades the undesired leaf constituents that lead to intense emulsification during extractions. Further reversed-phase chromatography of the extracts with polymeric resins removes the undesirable ginkgolic acids to amounts less than 10 ppm. The extracts are suited for pure terpene trilactone preparation, enrichment of terpene trilactone content in nutraceuticals, and preparations of low-flavonoid/high-terpene trilactone controls in medicinal studies. The four ginkgolides (ginkgolides A, B, C, J) and bilobalide isolated from the extract were identical in all respects with authentic specimens.
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IJS, KILJ, NUK, PNG, UL, UM
We discuss computation of approximate Gröbner bases at finite precision. We show how this can be used to deduce exact results for polynomial greatest common divisors and factorization. In particular ...we indicate an algorithm for factoring multivariate polynomials over the closure algebraic of the rationals.
To investigate the ventilatory and circulatory differences between eccentric (ECC) and concentric (CON) cycling exercise at submaximal, low-dose intensity from onset to end-exercise in healthy ...middle-aged participants.
Randomized controlled crossover trial.
The participants underwent 1 ECC and 1 CON test according to stepwise incremental exercise protocols at identical, submaximal intensities. Breath-by-breath analyses of ventilatory gas exchange and echocardiography were used to assess cardiopulmonary function during exercise.
24 healthy middle-aged, untrained participants (14 women, 10 men, 50±14 years) were included.
1 ECC and 1 CON test at submaximal intensities.
The main outcome was oxygen uptake (V'O2).
The V'O2 increase was reduced by -422 mL/min (-52%, 95% confidence interval: -513 to -292, P<.001) during ECC, as well as the ventilatory drive. Echocardiographic parameters, heart rate (-14%), cardiac output (-21%), stroke volume (-15%), and pulmonary artery pressure by tricuspid regurgitation pressure gradient (TRPG) (-26%) were also significantly reduced during ECC compared with CON at identical intensities. Participants reported significantly less dyspnea and unchanged perceived leg fatigue in ECC.
ECC was well tolerated, and significant reductions were observed in V'O2, ventilation, and right ventricular load compared with CON, even at low intensity levels. This study, conducted on healthy middle-aged participants, did not raise concerns that would hinder further investigation of the effects of ECC in patients with severely limited cardiopulmonary disease, and it calls for further research on this topic.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Provider: - Institution: European Heritage Awards Archive - Data provided by Europeana Collections- The heavy engine of the hammer mill, erected in 1664 (or earlier) along the course of the brook ...Urtel by Lukas Riemerschmid, was a wonder work of pre- industrial technology. The hammer wheel was over four metres tall and drove two hammers through the powerful 'Hammergrindel' (an approx . 10m long oak axle, 1.3 m in diameter) with wedged crown wheels. The somewhat smaller grinding wheel drove the grindstone in the grinding chamber and the bellow wheel the mighty bellows in the attic. The problematic future economic perspectives of the hammer mill business became conspicuous with the neglecting of urgent and necessary maintainence work. As a result in 1950-51 the dilapidated water wheels and the rotten oak axle ceased to function and had to be replaced by an electrical spring hammer. The valuable estate was given no further attention from any side. That the hammer mill was classified as a hi storical monument in a building group worthy of preserva t ion, did not prevent pressure from surrounding development and building activities. On one side irreparable building alterations were carried out, on the other side no measures at all were taken to prevent the building from decay. The smith trade ended in 1977, with the death of the owner.- Former Use: Hammer mill- Jury Citation: "Für die hervorragende Privatinitiative zur Rettung, Instandsetzung und Umnutzung eines kleinen Baudenkmals der Technikgeschichte unter Einbeziehung ökologischer Gesichtspunkte"- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
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