On the solution of a rational matrix equation arising in G-networks

We consider the problem of solving a rational matrix equation arising in the solution of G-networks. We propose and analyze two numerical methods: a fixed point iteration and the Newton–Raphson method. The fixed point iteration is shown to be globally convergent with linear convergence rate, while the Newton method is shown to have a local convergence, with quadratic convergence rate. Numerical experiments show the effectiveness of the proposed methods.     

Compact dual-profile corrugated circular waveguide horn

A new type of corrugated horn is presented. It is designed to have a dual-profile corrugation, yielding a more compact structure with respect to standard linear or sinusoidal profiled horns. It is also shown that the new design has some interesting features in terms of the phase centre location and its level of variation over the operating bandwidth     

An investigation of bistatic calibration techniques

Several popular bistatic calibration techniques are investigated and comparisons made between the relative merits of the various techniques. The analysis addresses sensitivity to object alignment error, sensitivity to polarization impurity, and ease of implementation. Both theoretical concepts and practical considerations are discussed based on measurements accomplished at the European Microwave Signature Laboratory of the European Commission Joint Research Center, Ispra, Italy. This facility has the capability to produce far-field fully polarimetric precision bistatic measurements in a 30-cm-diameter quiet zone, suitable for comparing different calibration methods.     

Therapy of rapidly progressive glomerulonephritis with immunosuppressive agents

Rapidly progressive glomerulonephritis is a kidney disease leading to sudden and definitive damages of the renal parenchyma and progressive impairment of its function until the complete failure. Histological findings of the changes are characterized with dominant glomerular lesions with crescentic formations. Early and intensive immunosuppressive therapy with pulse doses of steroids (Solumedrol 1.5 to 2.5 g), followed by Prednisolone 1 mg/kg every other day and cytostatic drugs (cyclophosphamide 1-2 mg-kg/every other day) discontinues the processes of specific and non-specific inflammation in the kidney and could enable regeneration of the kidney tissues with favorable outcome of the disease. Immunosuppressive therapy should be gradually lowered after two months, and applied for at least three to six months.     

Supercritical fluid extraction of bioactive lipids from the microalga Nannochloropsis sp.

Marine microalgae are recognised as an important renewable source of bioactive lipids with a high proportion of polyunsaturated fatty acids (PUFA), which have been shown to be effective in preventing or treating several diseases. For the extraction of oil from microalgae, supercritical CO₂ (ScCO₂) is regarded with interest, being safer than hexane and offering a negligible environmental impact, a short extraction time and a high‐quality final product. Whilst some experimental papers are available on the supercritical fluid extraction (SFE) of oil from microalgae, only limited information exists on the kinetics of the process. In such a contest, a mathematical model able to describe the kinetics of the SFE was applied to the recovery with ScCO₂ of lipids from Nannochloropsis sp., a marine microalga commonly used in aquaculture and characterised by a lipid fraction with a high PUFA content. The aim of this paper was to examine the effect of operating conditions on the kinetics of the SFE, on process yields and on the fatty acid composition of lipid extracts.     

Clinico-statistical investigation about cement dermatitis in Italy]

To define the prevalence of cement dermatitis (allergic contact dermatitis-ACD-and irritant contact dermatitis-ICD), two retrospective studies have been carried out in Italy: the first one based on the analysis of dermatitis cases ascribable to cement as defined by INAIL (Italian Institute for Industrial Accidents Insurance) from 1984 to 1992; the second one by surveying cement dermatitis cases in workers in the building industry aged between 16 and 70 carried out by Istituto di Clinica Dermatologica dell'Università di Bari from 1988 to 1994. The survey on INAIL data showed that in the years take into account 5,290 dermatitis cases included in item 41 of the occupational diseases table have been defined. About 80% of these cases have been observed in workers working as bricklayers and floor-layers. Therefore, given the remarkable exposure to cement in these professions, the prevalence of cement dermatitis in Italy has been estimated to 6 cases/province/year, even though it has not been possible recognize the clinical form of cement dermatitis. Moreover, the study showed that disabling cutaneous after-effects eligible for compensation have been observed in 30% of the cases defined by INAIL. The allergologic study carried out by Clinica Dermatologica has not only defined the incidence of contact dermatitis (ACD and ICD), in building workers, but it has also extrapoled dermatitis cases due to cement. As a whole, in the years taken into account, 166 occupational or mixed ACD cases and 77 occupational or mixed ICD have been diagnosed. The incidence of contact dermatitis ascribable to cement has equalled 79% among ACD and 88% among ICD, with a ratio of about 2 to 1 in favour of allergic forms. Among the chemicals tested, potassium bichromate showed the highest frequency of cases positive to patch tests. The skin site the most affected by cement dermatitis is hand, followed by upper limbs, lower limbs and feet. In the province of Bari, in the years taken into account, an average incidence of 28.4 cases per year of the two forms of cement dermatitis has been observed.     

Surface roughness and slope measurements using polarimetric SARdata

In this paper, the circular polarization coherence, ρ_RRLL , is investigated as a potential estimator of terrain surface roughness and small-scale slopes. The studies utilize microwave backscatter collected from 1) dielectric surfaces in an anechoic chamber and 2) a desert test site using P-, L-, and C-band NASA/JPL AIRSAR data. These experimental studies and supporting theory, indicate a sensitive decrease of |ρ_RRLL| with increasing surface roughness ks over a range 0 ⩽ ks ⩽ 1. For the present studies this decrease is caused largely by the depolarizing effects of small-scale surface slopes in the azimuth direction rather than by volume, or multiple scatter. For cases when the scatter is reflection symmetric, the value of |ρ_RRLL| depends on the surface roughness and on the local incidence angle. The dependence of |ρ_PRRLL| on the local incidence angle is supported by theory and experimental results. For these same scattering cases, however, |ρ_PRRLL| is independent of the surface dielectric constant. Estimation of the functional dependency of |ρ_PRRLL| versus ks, for a mid-range incidence angle, has been carried out using roughness estimates derived from an empirical model     

Modified NSGA‐II algorithm for multiobjective optimization of compact high‐efficiency square horns

High efficiency, compactness, light weight and low return loss are of high importance in antennas, especially in space applications. In this contribution a modified nondominated sorting genetic algorithm (NSGA‐II) is applied to the design of Horn antennas for discrete lens applications to achieve a Pareto‐optimal solution. Horn design is aimed not only towards higher possible efficiency but also towards large band and compactness. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.