1,203 research outputs found
Charge stripes due to electron correlations in the two-dimensional spinless Falicov-Kimball model
We calculate the restricted phase diagram for the Falicov-Kimball model on a
two-dimensional square lattice. We consider the limit where the conduction
electron density is equal to the localized electron density, which is the limit
related to the S_z=0 states of the Hubbard model. After considering over 20,000
different candidate phases (with a unit cell of 16 sites or less) and their
thermodynamic mixtures, we find only about 100 stable phases in the
ground-state phase diagram. We analyze these phases to describe where stripe
phases occur and relate these discoveries to the physics behind stripe
formation in the Hubbard model.Comment: (34 pages, 9 figures, submitted to Journal of Statistical Physics to
celebrate Elliott Lieb's 70th birthday
Formalising the Continuous/Discrete Modeling Step
Formally capturing the transition from a continuous model to a discrete model
is investigated using model based refinement techniques. A very simple model
for stopping (eg. of a train) is developed in both the continuous and discrete
domains. The difference between the two is quantified using generic results
from ODE theory, and these estimates can be compared with the exact solutions.
Such results do not fit well into a conventional model based refinement
framework; however they can be accommodated into a model based retrenchment.
The retrenchment is described, and the way it can interface to refinement
development on both the continuous and discrete sides is outlined. The approach
is compared to what can be achieved using hybrid systems techniques.Comment: In Proceedings Refine 2011, arXiv:1106.348
Is invasive macroalgae Lophocladia lallemandii inducing changes in epiphyte community of endemic bivalve Pinna nobilis?
Quantum Complex Scalar Field in the Two-Dimensional Spacetime with Closed Timelike Curves and a Time-Machine Problem
It is considered the quantum complex scalar field which obeys the
authomorphic condition in the two-dimensional spacetime with closed timelike
curves and the chronology horizon. The renormalized stress-energy tensor is
obtained. It is shown that the value of the stress-energy tensor is regular at
the chronology horizon for specific authomorphic parameters. Thus the
particular example of field configuration is given for which the Hawking's
chronology protection conjecture is violated.Comment: 21(Latex)Postscript file of the figure may be received from author,
CQG-94-100
Casimir Effect in closed spaces
As it is well known the topology of space is not totally determined by
Einstein's equations. It is considered a massless scalar quantum field in a
static Euclidean space of dimension 3. The expectation value for the energy
density in all compact orientable Euclidean 3-spaces are obtained in this work
as a finite summation of Epstein type zeta functions. The Casimir energy
density for these particular manifolds is independent of the type of coupling
with curvature. A numerical plot of the result inside each Dirichlet region is
obtained.Comment: Version accepted for publication. The most general coupling with
curvature is chose
Ecophysiology and dynamics of nitrogen removal bacteria in a sequencing batch reactor during wastewater treatment start‑up
Nitrogen removal communities performing wastewater treatment consist of ammonia oxidisers, nitrite oxidisers, denitrifiers,
and anammox bacteria, and the proportion and activity of particular microbial groups depend not only on the physiochemical
parameters of the bioreactor, but also on the composition of the inoculum. Nitrifiers and denitrifiers usually dominate
in conventional wastewater treatment systems due to the fact that nitrification and denitrification are the most commonly
used nitrogen removal processes. However, from the economical point of view in case of wastewater with high ammonia
concentrations, anammox-based technologies are desirable for their treatment. The disadvantage of such systems is slow
anammox bacteria growth, which extends an effective technological start-up. Thus, in this study, a fast start-up of the anammox
process supported with an anammox-rich inoculum was performed in a sequencing batch reactor (SBR). Using anammox
inoculation of SBR laboratory system, the start-up can be fastened to 85 days with 84.5% of nitrogen removal efficacy.
The spatial distribution of nitrogen removal bacteria analysed with fluorescent in situ hybridisation revealed that anammox
and nitrifiers are located side by side in the flocs and the relative number of ammonia and nitrite oxidisers decreased after
85 days of the experiment
Towards a method for rigorous development of generic requirements patterns
We present work in progress on a method for the engineering, validation and verification of generic requirements using domain engineering and formal methods. The need to develop a generic requirement set for subsequent system instantiation is complicated by the addition of the high levels of verification demanded by safety-critical domains such as avionics. Our chosen application domain is the failure detection and management function for engine control systems: here generic requirements drive a software product line of target systems. A pilot formal specification and design exercise is undertaken on a small (twosensor) system element. This exercise has a number of aims: to support the domain analysis, to gain a view of appropriate design abstractions, for a B novice to gain experience in the B method and tools, and to evaluate the usability and utility of that method.We also present a prototype method for the production and verification of a generic requirement set in our UML-based formal notation, UML-B, and tooling developed in support. The formal verification both of the structural generic requirement set, and of a particular application, is achieved via translation to the formal specification language, B, using our U2B and ProB tools
Altilix\uae Supplement Containing Chlorogenic Acid and Luteolin Improved Hepatic and Cardiometabolic Parameters in Subjects with Metabolic Syndrome: A 6 Month Randomized, Double-Blind, Placebo-Controlled Study
The objective was to evaluate the eects of 6 months of supplementation with Altilix\uae, containing chlorogenic acid and its derivatives, and luteolin and its derivatives, on cardiovascular risk and hepatic markers in subjects with metabolic syndrome (MetS). A randomized, double-blind, placebo-controlled study was performed in 100 subjects with MetS with a follow-up period of 6 months; 50 subjects were randomized to Altilix\uae (26 men and 24 women, mean age 63 8 years) and the other 50 to placebo (28 men and 22 women, mean age 63 11 years). Anthropometric, cardiometabolic, and hepatic parameters were assessed at baseline and at the end of follow-up. Carotid intima-media thickness and endothelial function were assessed by doppler ultrasound and by flow-mediated dilation of the brachial artery, respectively. The presence and degree of non-alcoholic fatty liver disease (NAFLD) was assessed by the fatty liver index (FLI), and subjects were divided into three subgroups: (1) without NAFLD; (2) with borderline NAFLD; and (3) with NAFLD. After 6 months of Altilix\uae supplementation, we found a significant improvement vs. placebo in most of the evaluated parameters, including body weight (2.40% (95% CI 3.79, 1.01); p < 0.001), waist circumference (2.76% (95% CI 4.55, 0.96); p = 0.003), HbA1c (0.95% (95% CI 1.22, 0.67); p < 0.001), plasma lipids, FLI (21.83% (95% CI 27.39, 16.27); p < 0.001), hepatic transaminases, flow-mediated dilation (10.56% (95% CI 5.00, 16.12); p < 0.001), and carotid intima-media thickness (39.48% (95% CI 47.98, 30.97); p < 0.001). Further, the improvement in cardiometabolic variables was independent of the degree of hepatic steatosis. Altilix\uae supplementation improved hepatic and cardio-metabolic parameters in MetS subjects. Altilix\uae supplementation was a beneficial approach in the management of hepatic and cardiometabolic alterations in MetS subjects
Postmarketing nutrivigilance safety profile: A line of dietary food supplements containing red yeast rice for dyslipidemia
Introduction: In the absence of a European standardized postmarketing food supplement surveillance system (nutrivigilance), some member states and companies have developed their own approaches to monitoring potential adverse reactions to secure a high level of product safety. This paper describes the use of a nutrivigilance system in monitoring the incidence of spontaneously reported suspected adverse reactions associated with food supplements containing red yeast rice (RYR). Material and methods: We report the data from a widely used product marketed under the trademark Armolipid/Armolipid Plus. Postmarketing information was collected in a voluntary nutrivigilance system established by the manufacturing company (Meda Pharma SpA, a Viatris Company, Monza, Italy). From 1st October 2004 to 31st December 2019, this system captured cases of suspected adverse reactions spontaneously reported by consumers, healthcare professionals, health authorities, regardless of causality. Results: The total number of case reports received mentioning the RYR food supplement product line was 542, in which 855 adverse events (AEs) were reported. The total reporting rate of AEs was estimated to be 0.037% of 2,287,449 exposed consumers. Of the 542 cases, 21 (0.0009% of exposed consumers) included suspected serious adverse events (SAEs). After careful investigation, 6 cases (0.0003% of consumers exposed) and 6 AEs were assessed by the manufacturer as serious and potentially related to exposure to the above-mentioned RYR-based nutraceutical. Conclusions: This nutrivigilance-derived data analysis clearly demonstrates a low prevalence of suspected adverse events associated with the red yeast rice product line. Consumer safety of food supplements could be generally improved by raising awareness of the importance of following the indications and warnings detailed in a food supplement's labeling
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