Inferring telescope polarization properties through spectral lines without linear polarization

We present a technique to determine the polarization properties of a telescope through observations of spectral lines that have no intrinsic linear polarization signals. For such spectral lines, any observed linear polarization must be induced by the telescope optics. We apply the technique to observations taken with the SPINOR at the DST and demonstrate that we can retrieve the characteristic polarization properties of the DST at three wavelengths of 459, 526, and 615 nm. We determine the amount of crosstalk between the intensity Stokes I and the linear and circular polarization states Stokes Q, U, and V, and between Stokes V and Stokes Q and U. We fit a set of parameters that describe the polarization properties of the DST to the observed crosstalk values. The values for the ratio of reflectivities X and the retardance tau match those derived with the telescope calibration unit within the error bars. Residual crosstalk after applying a correction for the telescope polarization stays at a level of 3-10%. We find that it is possible to derive the parameters that describe the polarization properties of a telescope from observations of spectral lines without intrinsic linear polarization signal. Such spectral lines have a dense coverage (about 50 nm separation) in the visible part of the spectrum (400-615 nm), but none were found at longer wavelengths. Using spectral lines without intrinsic linear polarization is a promising tool for the polarimetric calibration of current or future solar telescopes such as DKIST.Comment: 22 pages, 24 figures, accepted for publication in A&

Mathematical models for sleep-wake dynamics: comparison of the two-process model and a mutual inhibition neuronal model

Sleep is essential for the maintenance of the brain and the body, yet many features of sleep are poorly understood and mathematical models are an important tool for probing proposed biological mechanisms. The most well-known mathematical model of sleep regulation, the two-process model, models the sleep-wake cycle by two oscillators: a circadian oscillator and a homeostatic oscillator. An alternative, more recent, model considers the mutual inhibition of sleep promoting neurons and the ascending arousal system regulated by homeostatic and circadian processes. Here we show there are fundamental similarities between these two models. The implications are illustrated with two important sleep-wake phenomena. Firstly, we show that in the two-process model, transitions between different numbers of daily sleep episodes occur at grazing bifurcations.This provides the theoretical underpinning for numerical results showing that the sleep patterns of many mammals can be explained by the mutual inhibition model. Secondly, we show that when sleep deprivation disrupts the sleep-wake cycle, ostensibly different measures of sleepiness in the two models are closely related. The demonstration of the mathematical similarities of the two models is valuable because not only does it allow some features of the two-process model to be interpreted physiologically but it also means that knowledge gained from study of the two-process model can be used to inform understanding of the mutual inhibition model. This is important because the mutual inhibition model and its extensions are increasingly being used as a tool to understand a diverse range of sleep-wake phenomena such as the design of optimal shift-patterns, yet the values it uses for parameters associated with the circadian and homeostatic processes are very different from those that have been experimentally measured in the context of the two-process model

Circular e-waste ecosystems in necessity-driven contexts:The impact of formal institutional voids

Recent studies suggest an ecosystem view is most appropriate for understanding the impact of institutional voids on entrepreneurial activities. Expanding the focus to the entrepreneurial ecosystem is crucial for tackling complex low- and middle-income countries' (LMICs) environmental challenges, as the transition to circular e-waste management, which are heavily impacted by the institutional environment. Moreover, most entrepreneurs in LMICs engage in circular practices out of economic necessity, rather than environmental reasons. However, scholars have overlooked the effects of institutional voids on entrepreneurial ecosystems' potential to grow and realize environmental benefits. This study investigates how formal institutional voids impact the evolution of circular ecosystems in necessity-driven contexts in LMICs. We study the evolution of a circular e-waste ecosystem in Kenya and uncover two key phases: emergence and growth. We show that formal institutional voids' impact differs across phases; regulatory and contract enforcement voids create opportunities for informal and private actors to establish e-waste collection, repair, remanufacture, and recycle businesses, thereby facilitating the emergence of the circular ecosystem. However, labor market, capital market, product market, regulatory, and contract enforcement voids hamper its growth. Specifically, the lack of skills, equipment, guidelines, and financial incentives hinders advanced repairs and remanufactures and limits recycling opportunities, while the lack of formal e-waste infrastructure increases illegal dumping and negatively impacts human health and the environment. We develop propositions and a phase model to explain the impact of formal institutional voids on the evolution of circular e-waste ecosystems and the realization of environmental benefits in necessity-driven contexts.</p

In silico predictions of variant deleteriousness in the genomes of pig species

Predicting the deleteriousness of observed genomic variants has taken a step forward with the development of the Combined Annotation Dependent Depletion (CADD) [1] methodology, as it allows for comparable evaluations of variants on a genome-wide scale for coding and non-coding variants respectively. ..

Асимметричное сжатие цилиндрических оболочек продуктами детонации

Представлены результаты численного моделирования несимметричного сжатия упругопластических оболочек под действием продуктов детонации. Показаны особенности влияния технологических погрешностей и физико-механических характеристик материала оболочек и взрывчатых веществ на процессы деформирования.Представлені результати чисельного моделювання несиметричного стиснення упругопластических оболонок під дією продуктів детонації. Показано особливості впливу технологічних похибок і фізико-механічних характеристик матеріалу оболонок і вибухових речовин на процеси деформування.Results of numerical modeling the asymmetric compression of elastoplastic shells induced by the detonation products are given. Particular effects o f the manufacturing errors and physicomechanical characteristics o f the shell and explosive material on the deformation processes are shown

A photoelectron spectroscopy study of the electronic structure evolution in CuInSe2-related compounds at changing copper content

Evolution of the valence-band structure at gradually increasing copper content has been analysed by x-ray photoelectron spectroscopy (XPS) in In2Se3, CuIn5Se8, CuIn3Se5, and CuInSe2 single crystals. A comparison of these spectra with calculated total and angular-momentum resolved density-of-states (DOS) revealed the main trends of this evolution. The formation of the theoretically predicted gap between the bonding and non-bonding states has been observed in both experimental XPS spectra and theoretical DOS

Cavitation-induced force transition in confined viscous liquids under traction

We perform traction experiments on simple liquids highly confined between parallel plates. At small separation rates, we observe a simple response corresponding to a convergent Poiseuille flow. Dramatic changes in the force response occur at high separation rates, with the appearance of a force plateau followed by an abrupt drop. By direct observation in the course of the experiment, we show that cavitation accounts for these features which are reminiscent of the utmost complex behavior of adhesive films under traction. Surprisingly enough, this is observed here in purely viscous fluids.Comment: Submitted to Physical Review Letters on May 31, 2002. Related informations on http://www.crpp.u-bordeaux.fr/tack.htm

Subgingival Instrumentation for Treatment of Periodontitis. A Systematic Review

OBJECTIVES: To evaluate the efficacy of subgingival instrumentation (PICOS-1), sonic/ultrasonic/hand instruments (PICOS-2) and different subgingival instrumentation delivery protocols (PICOS-3) to treat periodontitis. METHODS: Systematic electronic search (CENTRAL/MEDLINE/EMBASE/SCOPUS/LILACS) to March 2019 was conducted to identify randomized controlled trials (RCT) reporting on subgingival instrumentation. Duplicate screening and data extraction were performed to formulate evidence tables and meta-analysis as appropriate. RESULTS: As only one RCT addressed the efficacy of subgingival instrumentation compared to supragingival cleaning alone (PICOS-1), baseline and final measures from 11 studies were considered. The weighted pocket depth (PD) reduction was 1.7 mm (95%CI: 1.3-2.1) at 6/8 months and the proportion of pocket closure was estimated at 74% (95%CI: 64-85). Six RCTs compared hand and sonic/ultrasonic instruments for subgingival instrumentation (PICOS-2). No significant differences were observed between groups by follow-up time point or category of initial PD. Thirteen RCTs evaluated quadrant-wise vs full-mouth approaches (PICOS-3). No significant differences were observed between groups irrespective of time-points or initial PD. Five studies reported patient-reported outcomes, reporting no differences between groups. CONCLUSIONS: Nonsurgical periodontal therapy by mechanical subgingival instrumentation is an efficacious means to achieve infection control in periodontitis patients irrespective of the type of instrument or mode of delivery. Prospero ID:CRD42019124887

Emerging evidence for CHFR as a cancer biomarker : from tumor biology to precision medicine

Novel insights in the biology of cancer have switched the paradigm of a "one-size-fits-all" cancer treatment to an individualized biology-driven treatment approach. In recent years, a diversity of biomarkers and targeted therapies has been discovered. Although these examples accentuate the promise of personalized cancer treatment, for most cancers and cancer subgroups no biomarkers and effective targeted therapy are available. The great majority of patients still receive unselected standard therapies with no use of their individual molecular characteristics. Better knowledge about the underlying tumor biology will lead the way toward personalized cancer treatment. In this review, we summarize the evidence for a promising cancer biomarker: checkpoint with forkhead and ring finger domains (CHFR). CHFR is a mitotic checkpoint and tumor suppressor gene, which is inactivated in a diverse group of solid malignancies, mostly by promoter CpG island methylation. CHFR inactivation has shown to be an indicator of poor prognosis and sensitivity to taxane-based chemotherapy. Here we summarize the current knowledge of altered CHFR expression in cancer, the impact on tumor biology and implications for personalized cancer treatment