Nonlocal Reductions of a Generalized Heisenberg Ferromagnet Equation

We study nonlocal reductions of coupled equations in $1+1$ dimensions of the Heisenberg ferromagnet type. The equations under consideration are completely integrable and have a Lax pair related to a linear bundle in pole gauge. We describe the integrable hierarchy of nonlinear equations related to our system in terms of generating operators. We present some special solutions associated with four distinct discrete eigenvalues of scattering operator. Using the Lax pair diagonalization method, we derive recurrence formulas for the conserved densities and find the first two simplest conserved densities.Comment: 14 pages. arXiv admin note: substantial text overlap with arXiv:1711.0635

Blood pressure and hypertension in type 1 diabetes mellitus patients with long duration

Type 1 diabetes mellitus (T1DM) has significantly better prognosis which has led to increased cardio-vascular diseases (CVD) prevalence. The detection of CVD risk factors and their treatment become tasks of paramount importance. Among them, high blood pressure (BP) is a target of primary purpose. Aim: to explore the blood pressure values, the prevalence of hypertension (HTN) and its management in patients with T1DM with long duration and without overt CVD, in comparison to matched controls. Participants and methods: totally, 124 patients with T1DM were matched to 59 controls by sex, age and approximate body mass index (BMI). All participants filled in questionnaires with information on demographics, physical activity, life style, concomitant diseases, treatments, presence of complications, etc. Blood samples were taken for laboratory and biomarkers investigation. Blood pressure was measured by investigators twice and the mean of the two measurements was used. HTN was accepted using standard definitions. BP values were compared using t-test. Multiple linear regression models with dependent variable BP measures and age, sex, BMI, presence of T1DM, glycated hemoglobin levels, creatinine levels as independent variables were created. ANOVA method was used to test the interaction of sex and presence of T1DM. Results: The mean age of the participants was 43.47 ± 10.1 years, 54% were males. The mean duration of T1DM was 25.31 ± 8.2 years and the mean HbA1c was 8.42 ± 1.8% for diabetic patients. The mean blood pressure measures in T1DM groups were higher than in controls, both in males and females. The difference reached significance for SBP and pulse pressure (PP). The presence of T1DM independently affected the BP values, after adjusting for major confounders. The mean adjusted differences between T1DM and controls were 8.37 mm Hg for SBP, 4.92 mm Hg for DBP, and 5.19 mm Hg for PP (p < 0.001). HTN was significantly more frequent in T1DM patients than in controls – 54% vs. 27%, p = 0.0001, mainly due to already known hypertension. BP control was insufficient – in only 36% and 13% of the treated hypertensive participants, respectively, for BP < 140/90 and < 130/80 mm Hg. The majority of the patients with HTN were treated with combination therapy, mostly single-pill fixed dosage but 30% of the hypertensive patients with diabetes did not take antihypertensive medications. Inhibitors of the renin-angiotensin system were the preferred class of medications. Conclusions: SBP and PP were significantly higher in middle-aged patients with T1DM with long duration than their control counterparts. The presence of HTN was significantly more common in T1DM. Although treated according to the current recommendations, the control of BP was far from effective. These results show the need for constant screening of patients with T1DM for HTN and other risk factors and for more aggressive antihypertensive treatment to prevent future CVD events

Black Sea coastal forecasting system

The Black Sea coastal nowcasting and forecasting system was built within the framework of EU FP6 ECOOP (European COastalshelf sea OPerational observing and forecasting system) project for five regions: the south-western basin along the coasts of Bulgaria and Turkey, the north-western shelf along the Romanian and Ukrainian coasts, coastal zone around of the Crimea peninsula, the north-eastern Russian coastal zone and the coastal zone of Georgia. The system operates in the real-time mode during the ECOOP project and afterwards. The forecasts include temperature, salinity and current velocity fields. Ecosystem model operates in the off-line mode near the Crimea coast

On the (Non)-Integrability of KdV Hierarchy with Self-consistent Sources

Non-holonomic deformations of integrable equations of the KdV hierarchy are studied by using the expansions over the so-called "squared solutions" (squared eigenfunctions). Such deformations are equivalent to perturbed models with external (self-consistent) sources. In this regard, the KdV6 equation is viewed as a special perturbation of KdV equation. Applying expansions over the symplectic basis of squared eigenfunctions, the integrability properties of the KdV hierarchy with generic self-consistent sources are analyzed. This allows one to formulate a set of conditions on the perturbation terms that preserve the integrability. The perturbation corrections to the scattering data and to the corresponding action-angle variables are studied. The analysis shows that although many nontrivial solutions of KdV equations with generic self-consistent sources can be obtained by the Inverse Scattering Transform (IST), there are solutions that, in principle, can not be obtained via IST. Examples are considered showing the complete integrability of KdV6 with perturbations that preserve the eigenvalues time-independent. In another type of examples the soliton solutions of the perturbed equations are presented where the perturbed eigenvalue depends explicitly on time. Such equations, however in general, are not completely integrable.Comment: 16 pages, no figures, LaTe

Comparison of the Hα circumstellar disks in Be/X-ray binaries and Be stars

We present a comparative study of the circumstellar disks in Be/X-ray binaries and isolated Be stars based upon the Hα emission line. From this comparison it follows that the overall structure of the disks in the Be/X-ray binaries is similar to the disks of other Be stars, i.e. they are axisymmetric and rotationally supported. The factors for the line broadening (rotation and temperature) in the disks of the Be stars and the Be/X-ray binaries seem to be identical. However, we do detect some intriguing differences between the envelopes. On average, the circumstellar disks of the Be/X-ray binaries are twice as dense as the disks of the isolated Be stars. The different distribution of the Be/X-ray binaries and the Be stars seen in the full with half maximum versus peak separation diagram indicates that the disks in Be/X-ray binaries have on average a smaller size, probably truncated by the compact object.Reig Torres, Pablo, [email protected] ; Fabregat Llueca, Juan, [email protected]

Enzymatic hydrolysis of sorghum straw using native cellulase produced by T. reesei NCIM 992 under solid state fermentation using rice straw

Cellulose is a major constituent of renewable lignocellulosic waste available in large quantities and is considered the most important reservoir of carbon for the production of glucose, for alternative fuel and as a chemical feedstock. Over the past decade, the emphasis has been on the enzymatic hydrolysis of cellulose to glucose and the efficiency of which depends on source of cellulosic substrate, its composition, structure, pretreatment process, and reactor design. In the present study, efforts were made to produce cellulase enzyme using rice straw. The produced enzyme was used for the hydrolysis of selected lignocellulosic substrate, i.e., sorghum straw. When rice straw was used as a substrate for cellulase production under solid state fermentation, the highest enzyme activity obtained was 30.7 FPU/gds, using T. reesei NCIM 992. 25 FPU/g of cellulase was added to differently treated (native, alkali treated, alkali treated followed by 3% acid treated and alkali treated followed by 3 and 5% acid treated) sorghum straw and hydrolysis was carried out at 50 °C for 60 h. 42.5% hydrolysis was obtained after 36 h of incubation. Optimization of enzyme loading, substrate concentration, temperature, time and buffer yielded a maximum of 546.00 ± 0.55 mg/g sugars (54.60 ± 0.44 g/l) with an improved hydrolysis efficiency of 70 ± 0.45%. The enzymatic hydrolyzate can be used for fermentation of ethanol by yeasts

Nonlocal Reductions of the Ablowitz–Ladik Equation

Our purpose is to develop the inverse scattering transform for the nonlocal semidiscrete nonlinear Schrödinger equation (called the Ablowitz–Ladik equation) with PT symmetry. This includes the eigenfunctions (Jost solutions) of the associated Lax pair, the scattering data, and the fundamental analytic solutions. In addition, we study the spectral properties of the associated discrete Lax operator. Based on the formulated (additive) Riemann–Hilbert problem, we derive the one- and two-soliton solutions for the nonlocal Ablowitz–Ladik equation. Finally, we prove the completeness relation for the associated Jost solutions. Based on this, we derive the expansion formula over the complete set of Jost solutions. This allows interpreting the inverse scattering transform as a generalized Fourier transform

Nonlocal Reductions of The Multicomponent Nonlinear Schrödinger Equation on Symmetric Spaces

Our aim is to develop the inverse scattering transform for multicomponent generalizations of nonlocal reductions of the nonlinear Schrödinger (NLS) equation with PT symmetry related to symmetric spaces. This includes the spectral properties of the associated Lax operator, the Jost function, the scattering matrix, the minimum set of scattering data, and the fundamental analytic solutions. As main examples, we use theManakov vector Schrödinger equation (related to A.III-symmetric spaces) and the multicomponent NLS (MNLS) equations of Kulish–Sklyanin type (related to BD.I-symmetric spaces). Furthermore, we obtain one- and two-soliton solutions using an appropriate modification of the Zakharov–Shabat dressing method. We show that the MNLS equations of these types admit both regular and singular soliton configurations. Finally, we present different examples of one- and two-soliton solutions for both types of models, subject to different reductions

Past and recent trends in the western Black Sea storminess

Storms are one of the most important phenomena producing coastal hazards and endangering human life and activities. In recent decades storm climate has become a subject of increased public awareness and knowledge of this issue can help the society to meet future challenges related to extreme storm manifestation. Therefore, the goal of this study is to assess trends in past and recent storminess in the western Black Sea. The analysis of storm climate is based on a continuous hindcast dataset covering a substantial historical time-span of 63 yr (1948–2010). It was used to create a storm population and to estimate properties describing storminess (proxies). This was done by introduction of criteria allowing separation of events with low probability of occurrence and at the same time keeping the information on their pattern, i.e. properties of storm phases. Eleven storminess proxies were analysed and the most indicative appeared to be storm duration; integral, mean and specific storm wave energy; and wind velocity and direction, which were obtained for each storm season. &lt;br&gt;&lt;br&gt; While experiencing significant variability on a quasi-decadal scale, no significant upward or downward trends in storminess were detected. For almost all proxies, an increasing trend until the 1980s or the 1990s and a return to average or even calm conditions in the late 2000s are traceable. On this background, a steady although not significant increase of wind velocity was detected. Results also indicate an alteration of storm pattern, manifested as shortening of storm duration due to a shift of the prevailing direction of storm forcing winds to the north. Nevertheless, incident wave energy in the storms' most intense phase remains significant. The obtained results are discussed with regard to the influence of the North Atlantic Oscillation on the hydrometeorological pattern of the Black Sea region as a part of the European-Atlantic area, in particular with respect to the cyclonic activity

Structural equivalence and differential item functioning in the Social Axioms Survey

The present chapter focuses on the assessment of bias and equivalence of the Social Axioms Survey in a 41-country data set analyzed at the individual level. Two main issues are examined. The first, structural equivalence, addresses the question to what extent the constructs underlying the Social Axioms Survey are universal across the 41 countries. The second, differential item functioning, deals with the question of whether there are particular items or countries that are problematic. Exploratory factor analyses (testing structural equivalence) and analyses of variance (testing item bias) were carried out. The equivalence of the scales was adequate, but neither the exploratory factor analysis nor the analyses of variance provided indisputable support for the equivalence of any scale. The results led to three main conclusions: (1) social axioms show important similarities across cultures; (2) numerical comparisons of scores obtained in different countries must be treated with caution; (3) the observed bias was due to both item and country characteristics. Several items showed secondary (i.e., deviant) loadings in the global factorial solution. Level of economic development and religion (main religious denomination of a country) were associated with bias. In the discussion of our findings, a balanced treatment is recommended to account for both instrument and country characteristics that cause bias