Stability borders of feedback control of delayed measured systems

When stabilization of unstable periodic orbits or fixed points by the method given by Ott, Grebogi and Yorke (OGY) has to be based on a measurement delayed by $\tau$ orbit lengths, the performance of unmodified OGY method is expected to decline. For experimental considerations, it is desired to know the range of stability with minimal knowledge of the system. We find that unmodified OGY control fails beyond a maximal Ljapunov number of $\lambda_{max}=1+\frac{1}{\tau}$. In this paper the area of stability is investigated both for OGY control of known fixed points and for difference control of unknown or inaccurately known fixed points. An estimated value of the control gain is given. Finally we outline what extensions have to be considered if one wants to stabilize fixed points with Ljapunov numbers above $\lambda_{max}$.Comment: 5 pages LaTeX using revtex and epsfig (4 figs included). Revised versio

Dilations and constrained algebras

It is well known that unital contractive representations of the disk algebra are completely contractive. Let A denote the subalgebra of the disk algebra consisting of those functions f whose first derivative vanishes at 0. We prove that there are unital contractive representations of A which are not completely contractive, and furthermore provide a Kaiser and Varopoulos inspired example for A and present a characterization of those contractive representations of A which are completely contractive. In the positive direction, for the algebra of rational functions with poles off the distinguished variety V in the bidisk determined by (z-w)(z+w)=0, unital contractive representations are completely contractive.Comment: New to version 2 is a proof of rational dilation for the distinguished variety in the bidisk determined by (z-w)(z+w)=

The Role and Prospects of Rare Earth Metals in the Development of Physical-Mechanical Characteristics and Applications of Deformable Aluminum Alloys

В статье рассмотрены результаты отечественных разработок и применения алюминиевых сплавов в виде катаных, экструдированных и штампованных полуфабрикатов в качестве ренгеноконтрастных материалов, проводников тока, стойких к воздействию высоких температур, и конструкционных материалов различного назначенияIn the article the results of domestic development and application of aluminum alloys in the form of a rolled, extruded and forged semi-finished products as X-ray contrast materials, conductors, resistant to high temperatures, and structural materials of different destinatio

“What’s his is his and what’s mine is his”: Financial power and economic abuse of women in Aotearoa

AIM: This study aimed to understand the experiences and effects of economic abuse for women in Aotearoa New Zealand, particularly in relation to methods of coercive control, with the intention of developing risk matrices to be used by practitioners.METHODS: We conducted a survey with 448 respondents—with 398 the focus of analysis for this article. The survey contained a combination of scaling and open-ended questions.FINDINGS: Abusers employed a range of abusive methods to restrict victims’ freedom and exercise domination. These abusive behaviours seemed to follow traditional hegemonic construction of masculinity as synonymous with “provider” in that many of these methods relied on the reproduction of gendered stereotypes which subjugate women to a subordinate position in the household. Women experienced a range of adverse emotional impacts as a result of this abuse

Coastal sea surface temperature variability along the south coast of South Africa and the relationship to regional and global climate

The southern coastline of South Africa is approximately zonal, with a wide (up to 270 km) shelf region. Intense thermoclines are known to be established by insolation on the inner shelf region during summer, upwelling is generated by easterly-component winds, and occasionally Agulhas Current water can be advected close to the coast, particularly in the east. These processes induce daily and seasonal fluctuations of coastal sea-surface temperature (SST), but their influence over longer time scales (interannual) has not yet been tested. Here time series of SST ranging from 12 to 31 years are examined for inter-relationships with local and regional winds, and the southern oscillation index (SOI). The emphasis is on the summer period, and it is found that the correlation between SST and major axis wind anomalies can be improved substantially by considering the frequency of occurrence of winds above given thresholds. Moreover, winds and SSTs are also correlated with the SOI, such that fewer easterly-component winds are experienced at low phases (El Nino) with consequent increases in coastal SST, and correspondingly more easterly-component winds at high phases (La Nina) result in decreased coastal SST; however, these relationships did not hold for a measuring site within a large open bay area. Long-term trends are also established, with substantial increases in SST (0.25°C/decade) in association with greater increases in air temperature (0.36°C/ decade)

CD8+ T-Cells in Juvenile-Onset SLE: From Pathogenesis to Comorbidities

Diagnosis of systemic lupus erythematosus (SLE) in childhood [juvenile-onset (J) SLE], results in a more severe disease phenotype including major organ involvement, increased organ damage, cardiovascular disease risk and mortality compared to adult-onset SLE. Investigating early disease course in these younger JSLE patients could allow for timely intervention to improve long-term prognosis. However, precise mechanisms of pathogenesis are yet to be elucidated. Recently, CD8+ T-cells have emerged as a key pathogenic immune subset in JSLE, which are increased in patients compared to healthy individuals and associated with more active disease and organ involvement over time. CD8+ T-cell subsets have also been used to predict disease prognosis in adult-onset SLE, supporting the importance of studying this cell population in SLE across age. Recently, single-cell approaches have allowed for more detailed analysis of immune subsets in JSLE, where type-I IFN-signatures have been identified in CD8+ T-cells expressing high levels of granzyme K. In addition, JSLE patients with an increased cardiometabolic risk have increased CD8+ T-cells with elevated type-I IFN-signaling, activation and apoptotic pathways associated with atherosclerosis. Here we review the current evidence surrounding CD8+ T-cell dysregulation in JSLE and therapeutic strategies that could be used to reduce CD8+ T-cell inflammation to improve disease prognosis

Plant-based dietary changes may improve symptoms in patients with systemic lupus erythematosus

INTRODUCTION: Previous studies have reported that patients affected by systemic lupus erythematosus (SLE) are interested in using diet to treat fatigue, cardiovascular disease and other symptoms. However, to date, there is insufficient information regarding the ways for patients to modify their diet to improve SLE symptoms. We investigated the relationship between the eating patterns of SLE patients and their self-reported disease symptoms and general aspects of health. METHODS: A UK-based, online survey was developed, in which patients with SLE were asked about their attitudes and experiences regarding their SLE symptoms and diet. RESULTS: The majority (>80%) of respondents that undertook new eating patterns with increased vegetable intake and/or decreased intake of processed food, sugar, gluten, dairy and carbohydrates reported benefiting from their dietary change. Symptom severity ratings after these dietary changes were significantly lower than before (21.3% decrease, p<0.0001). The greatest decreases in symptom severity were provided by low/no dairy (27.1% decrease), low/no processed foods (26.6% decrease) and vegan (26% decrease) eating patterns (p<0.0001). Weight loss, fatigue, joint/muscle pain and mood were the most cited symptoms that improved with dietary change. CONCLUSION: SLE patients who changed their eating patterns to incorporate more plant-based foods while limiting processed foods and animal products reported improvements in their disease symptoms. Thus, our findings show promises in using nutrition interventions for the management of SLE symptoms, setting the scene for future clinical trials in this area. Randomised studies are needed to further test whether certain dietary changes are effective for improving specific symptoms of SLE

Persistent random walk on a one-dimensional lattice with random asymmetric transmittances

We study the persistent random walk of photons on a one-dimensional lattice of random asymmetric transmittances. Each site is characterized by its intensity transmittance t (t') for photons moving to the right (left) direction. Transmittances at different sites are assumed independent, distributed according to a given probability density Distribution. We use the effective medium approximation and identify two classes of probability density distribution of transmittances which lead to the normal diffusion of photons. Monte Carlo simulations confirm our predictions.Comment: 7 pages, submitted to Phys. Rev.

Use of groundwater lifetime expectancy for the performance assessment of a deep geologic waste repository: 1. Theory, illustrations, and implications

Long-term solutions for the disposal of toxic wastes usually involve isolation of the wastes in a deep subsurface geologic environment. In the case of spent nuclear fuel, if radionuclide leakage occurs from the engineered barrier, the geological medium represents the ultimate barrier that is relied upon to ensure safety. Consequently, an evaluation of radionuclide travel times from a repository to the biosphere is critically important in a performance assessment analysis. In this study, we develop a travel time framework based on the concept of groundwater lifetime expectancy as a safety indicator. Lifetime expectancy characterizes the time that radionuclides will spend in the subsurface after their release from the repository and prior to discharging into the biosphere. The probability density function of lifetime expectancy is computed throughout the host rock by solving the backward-in-time solute transport adjoint equation subject to a properly posed set of boundary conditions. It can then be used to define optimal repository locations. The risk associated with selected sites can be evaluated by simulating an appropriate contaminant release history. The utility of the method is illustrated by means of analytical and numerical examples, which focus on the effect of fracture networks on the uncertainty of evaluated lifetime expectancy.Comment: 11 pages, 8 figures; Water Resources Research, Vol. 44, 200