Search results for "rings"
showing 10 items of 434 documents
A note on coverings with special fibres and monodromy group $ S_{d}$
2012
We consider branched coverings of degree over with monodromy group , points of simple branching, special points and fixed branching data at the special points, where is a smooth connected complex projective curve of genus , and , are integers with . We prove that the corresponding Hurwitz spaces are irreducible if .
Automatic Calibration of an Industrial RGB-D Camera Network Using Retroreflective Fiducial Markers
2019
This paper describes a non-invasive, automatic, and robust method for calibrating a scalable RGB-D sensor network based on retroreflective ArUco markers and the iterative closest point (ICP) scheme. We demonstrate the system by calibrating a sensor network comprised of six sensor nodes positioned in a relatively large industrial robot cell with an approximate size of 10 m × 10 m × 4 m . Here, the automatic calibration achieved an average Euclidean error of 3 c m at distances up to 9.45 m . To achieve robustness, we apply several innovative techniques: Firstly, we mitigate the ambiguity problem that occurs when detecting a marker at long range or low resolution by comparing the…
A Pragmatic Characterization of Concept Algebra
2017
Taking into account the framework of denotational mathematics as seen by Yingxu Wang, in this paper the author wishes to implement a possible further pragmatic (context-depend) dimension into the algebraic structure of concept algebra. One of the main problems of software science is that regarding context-depend question of a programming language. Indeed, attention has been paid above all to syntactic and semantic dimensions of a programming language, neglecting the pragmatic one concerning context. The author has tried to face this question providing a first denotational mathematics structure taking into account a possible pragmatic dimension.
The exterior derivative as a Killing vector field
1996
Among all the homogeneous Riemannian graded metrics on the algebra of differential forms, those for which the exterior derivative is a Killing graded vector field are characterized. It is shown that all of them are odd, and are naturally associated to an underlying smooth Riemannian metric. It is also shown that all of them are Ricci-flat in the graded sense, and have a graded Laplacian operator that annihilates the whole algebra of differential forms.
Safety and efficacy of a fixed-dose combination regimen of grazoprevir, ruzasvir, and uprifosbuvir with or without ribavirin in participants with and…
2017
Background There is a need for hepatitis C virus (HCV) therapies with excellent efficacy across genotypes and in diverse populations. Part A of the C-CREST-1 and C-CREST-2 trials led to the selection of a three-drug regimen of grazoprevir (MK-5172; an HCV NS3/4A protease inhibitor; 100 mg/day) plus ruzasvir (MK-8408; an NS5A inhibitor; 60 mg/day) plus uprifosbuvir (MK-3682; an HCV NS5B polymerase inhibitor; 450 mg/day). Part B of the studies tested this combination as a single formulation in different treatment durations in a broader population. Methods Part B of these randomised, phase 2, open-label clinical trials enrolled individuals from 15 countries who were chronically infected with H…
Integrating fire-scar, charcoal and fungal spore data to study fire events in the boreal forest of northern Europe
2019
Fire is a major disturbance agent in the boreal forest, influencing many current and future ecosystem conditions and services. Surprisingly few studies have attempted to improve the accuracy of fire-event reconstructions even though the estimates of the occurrence of past fires may be biased, influencing the reliability of the models employing those data (e.g. C stock, cycle). This study aimed to demonstrate how three types of fire proxies – fire scars from tree rings, sedimentary charcoal and, for the first time in this context, fungal spores of Neurospora – can be integrated to achieve a better understanding of past fire dynamics. By studying charcoal and Neurospora from sediment cores f…
Mobila sirdsdarbības novērošanas ierīce
2015
Pēc slimību profilakses un kontroles centra datiem Latvijā galvenais nāves iemesls joprojām ir sirds un asinsvadu slimības. Viens no galvenajiem sirds un asinsvadu slimību noteicošajiem testiem ir elektrokardiogrammas veikšana ar elektrokardiogrāfa palīdzību. Šo testu var veikt trīs veidos – stacionāri, slodzes un ilglaicīgi. Stacionārais tests ir visvairāk pielietotais, bet ilgst mazāk par minūti. Slodzes testu veic, ja pacientam ir sūdzības par sirdsdarbību nodarbojoties ar fiziskām aktivitātēm. Ilglaicīgo testu veic, lai novērotu sirdsdarbību ilgākā laika periodā, piemēram, 24 stundas. Izmantojot Holter sistēmu pacientam ir neērti, jo pēc testa šī ierīce ir jāatgriež ārsta kabinetā, kur …
Parastās priedes radiālā pieauguma parametriska analīze vides izmaiņu noteikšanai
2013
Elektroniskā versija nesatur pielikumus
Enhanced nanoscopy of individual CsPbBr3 perovskite nanocrystals using dielectric sub-micrometric antennas
2020
We demonstrate an efficient, simple, and low-cost approach for enhanced nanoscopy in individual green emitting perovskite (CsPbBr3) nanocrystals via TiO2 dielectric nanoantenna. The observed three- to five-fold emission enhancement is attributed to near-field effects and emission steering promoted by the coupling between the perovskite nanocrystals and the dielectric sub-micrometric antennas. The dark-field scattering configuration is then exploited for surface-enhanced absorption measurements, showing a large increase in detection sensitivity, leading to the detection of individual nanocrystals. Due to the broadband spectral response of the Mie sub-micrometric antennas, the method can be e…
Dialogic Feminist Gatherings: Impact of the Preventive Socialization of Gender-Based Violence on Adolescent Girls in Out-of-Home Care
2020
Gender-based violence is a social scourge with an increasing incidence at younger ages. Many studies have focused on finding effective solutions for overcoming this problem