Two-peaked and flat-top perfect bright solitons in epsilon-near-zero nonlinear metamaterials: novel Kerr self-trapping mechanisms

We analytically investigate transverse magnetic (TM) spatial bright solitons, as exact solutions of Maxwell's equations, propagating through nonlinear metamaterials whose linear dielectric permittivity is very close to zero and whose effective nonlinear Kerr parameters can be tailored to achieve values not available in standard materials. Exploiting the fact that, in the considered medium, linear and nonlinear polarization can be comparable at feasible and realistic optical intensities, we identify two novel self-trapping mechanisms able to support two-peaked and flat-top solitons, respectively. Specifically, these two novel mechanisms are based on the occurrence of critical points at which the effective nonlinear permittivity vanishes, the two mechanisms differing in the way the compensation between linear and nonlinear polarization is achieved through the non-standard values of the nonlinear parameters.Comment: 7 pages, 4 figure

Extreme nonlinear electrodynamics in metamaterials with very small linear dielectric permittivity

We consider a sub-wavelength periodic layered medium whose slabs are filled by arbitrary linear metamaterials and standard nonlinear Kerr media and we show that the homogenized medium behaves as a Kerr medium whose parameters can assume values not available in standard materials. Exploiting such a parameter availability, we focus on the situation where the linear relative dielectric permittivity is very small thus allowing the observation of the extreme nonlinear regime where the nonlinear polarization is comparable with or even greater than the linear part of the overall dielectric response. The behavior of the electromagnetic field in the extreme nonlinear regime is very peculiar and characterized by novel features as, for example, the transverse power flow reversing. In order to probe the novel regime, we consider a class of fields (transverse magnetic nonlinear guided waves) admitting full analytical description and we show that these waves are allowed to propagate even in media with $\epsilon0$ since the nonlinear polarization produces a positive overall effective permittivity. The considered nonlinear waves exhibit, in addition to the mentioned features, a number of interesting properties like hyper-focusing induced by the phase difference between the field components.Comment: 12 pages, 7 figure

Effect of sulphur poisoning on perovskite catalysts prepared by flame-pyrolysis

ABO(3) perovskite-like catalysts are known to be sensitive to sulphur-containing compounds. Possible solutions to increase resistance to sulphur are represented by either catalyst bed protection with basic guards or catalyst doping with different transition or noble metals. In the present work La((1-x))A(x)'CoO(3), La((1-x))A(x)'MnO(3) and La((1-x))A(x)'FeO(3), with A' = Ce, Sr and x = 0, 0.1, 0.2, either pure or doped with noble metals (0.5 wt% Pt or Pd), were prepared in nano-powder form by flame-pyrolysis. All the catalysts were tested for the catalytic flameless combustion of methane, monitoring the activity by on-line mass spectrometry. The catalysts were then progressively deactivated in operando with a new procedure, consisting of repeated injection of some doses of tetrahydrothiophene (THT), usually employed as odorant in the natural gas grid, with continuous analysis of the transient response of the catalyst. The activity tests were then repeated on the poisoned catalyst. Different regenerative treatments were also tried, either in oxidising or reducing atmosphere. Among the unsubstituted samples, higher activity and better resistance to poisoning have been observed in general with manganites with respect to the corresponding formulations containing Co or Fe at the B-site. The worst catalyst showed LaFeO(3), from both the points of view of activity and of resistance to sulphur poisoning. La(0.9)Sr(0.1)MnO(3) showed, the best results, exhibiting very high activity and good resistance even after the addition of up to 8.4 mg of THT/g of catalyst. Interesting results were attained also by adding Sr to Co-based perovskites. Sr showed a first action by forcing Mn or Co in their highest oxidation state, but, in addition, it could also act as a sulphur guard, likely forming stable sulphates due to its basicity. Among noble metals, Pt doping proved beneficial in improving the activity of both the fresh and the poisoned catalyst

Optimalisasi Konsentrasi Sukrosa Dan Ammonium Sulfat Pada Produksi Nata De Citrus Menggunakan Sari Jeruk Afkir

This study aimed to explore the use of rejected citrus fruit as raw material for making nata and to obtain the best concentration of sucrose and ammonium sulfate on the characteristics of nata de citrus produced. Research conducted experiments used a Completely Randomized Design (CRD) Factorial model with two factor treatments and three replications. The first factor was the concentration of sucrose with four levels, namely 0, 2.5, 5 and 7.5% and the second factor was the concentration of ammonium sulfate with three levels, namely 0.5, 0.6 and 0.7%. The results showed interaction of sucrose and ammonium sulfate concentrations significantly affected the acquisition of the water content and reducing sugar content. Sucrose concentrations significantly affected againts the value of water content, degree of acidity (pH), thickness, wet weight, yield and reducing sugar content. The concentrations of ammonium sulfate significantly affected againts water content, thickness, wet weight, yield and reducing sugar content. The best treatment of S3A3 (7,5% sucrose and 0,7% ammonium sulfate) result the degree of water content 88,94%, degree of acidity (pH) 3,57, thickness 4,58 mm, wet weight 132,20 g, yield 30,28% and reducing sugar content 1,89% of nata de citrus was relatively better than other treatments

Use of Cross-Species Amplification Markers for Pollen-Medicated Gene Flow Determination in \u3cem\u3eTrifolium Polymorphum\u3c/em\u3e Poiret

The species Trifolium polymorphum Poiret is endemic to Uruguay and is widespread in native grasslands throughout the country. Preliminary observations suggested that the aerial flowers are chasmogamous (open at maturity for potential cross-pollination) while the basal flowers are cleistogamous. Several approaches have been practised to determine the reproductive system of forage legumes by the aid of co-dominant markers (Real et al., 2004; Dalla Rizza et al., 2004). The aim of this study is to explore cross-species amplification as a quick approach to obtain co-dominant markers to study the breeding system of T. polymorphum

The Correlation Between Characteristic Host, Physics Environment and Health Service to Dengue Hemorrhagic Fever (Dhf) in Working Area of Public Health Center of Talang Ubi Pendopo in 2012

Background : DHF in Indonesia included A category in the stratification by WHO indicate high rates of hospitalization and deaths due to DHF. Preliminary survey which has been conducted showed in Working Area of Public Health Centre DHF cases is high 51 cases during 2011,. Therefore, the aim of this study was to identifiy the correlation between Characteristics Host, Physics Environment and Health Service to DHF in Working Area of Public Health Centre of Talang Ubi in period of 2012. Method : Used analytical survey study with cross sectional approach. Data collection was conducted by interview and observation using questionnaire and using checklist. The data were analyzed by method of univariate and bivariate with chi square analysis. The number of samples in this study were 85 head of household in Working Area of Public Health Centre of Talang Ubi Pendopo with Sampling Technique used is Simple Random Sampling Techniques. Resulst : From total of six variables, three variables associated with DHF, that are age (p-value=0.002, PR=4.383), physics environment (p-value=0.001, PR=4.750), and health service (p-value=0.022, PR=2.936), while sex (p-value=0.996, PR=1.002), education (p-value=0.093, PR=2.182), and job (p-value=0.216, PR=1.766) has no correlation to the incidence of DHF. Conclution : Public Health Centre of Talang Ubi need to improve health service through promotion and prevention to reduce the transmission and DHF case, improve support of health workers to implement the DHF programs with the best, and the society should also support by improving the environment around the house so as not to be a breeding place of Aedes aegypti and implement the PSN-Aedes aegypti

Metabolic aspects of cardiovascular diseases: Is FoxO1 a player or a target?

The O subfamily of forkhead (FoxO) 1 is a crucial regulator of cell metabolism in several tissues, including the heart, where it is involved in cardiac regulation of glucose and lipid metabolic pathways, and endothelium, controlling the levels of some relevant biomarkers in atherosclerotic process. Despite the growing understanding of FoxO1 biology, the metabolic consequences of FoxO1 modifications and its implication in CVD, atherosclerosis and T2DM are still not incompletely described. In this review we discuss how FoxO1 affects cardiovascular pathophysiology and which of its effects should be restrained or enhanced to preserve endothelial and heart functions

Differential biosynthesis and cellular permeability explain longitudinal gibberellin gradients in growing roots.

Control over cell growth by mobile regulators underlies much of eukaryotic morphogenesis. In plant roots, cell division and elongation are separated into distinct longitudinal zones and both division and elongation are influenced by the growth regulatory hormone gibberellin (GA). Previously, a multicellular mathematical model predicted a GA maximum at the border of the meristematic and elongation zones. However, GA in roots was recently measured using a genetically encoded fluorescent biosensor, nlsGPS1, and found to be low in the meristematic zone grading to a maximum at the end of the elongation zone. Furthermore, the accumulation rate of exogenous GA was also found to be higher in the elongation zone. It was still unknown which biochemical activities were responsible for these mobile small molecule gradients and whether the spatiotemporal correlation between GA levels and cell length is important for root cell division and elongation patterns. Using a mathematical modeling approach in combination with high-resolution GA measurements in vivo, we now show how differentials in several biosynthetic enzyme steps contribute to the endogenous GA gradient and how differential cellular permeability contributes to an accumulation gradient of exogenous GA. We also analyzed the effects of altered GA distribution in roots and did not find significant phenotypes resulting from increased GA levels or signaling. We did find a substantial temporal delay between complementation of GA distribution and cell division and elongation phenotypes in a GA deficient mutant. Together, our results provide models of how GA gradients are directed and in turn direct root growth