Observation of amplified phase-conjugate reflection and optical parametric oscillation by degenerate four-wave mixing in a transparent medium

We report on the observation of amplified reflection and optical parametric oscillation via degenerate four-wave mixing in a nonresonant medium. The process is mediated through the third-order nonlinear susceptibility in a transparent liquid medium, CS2. A collinear mixing geometry is utilized to obtain long interaction lengths and polarization discrimination is used to separate the pump and signal fields

Compensation for channel dispersion by nonlinear optical phase conjugation

It is proposed that the process of nonlinear optical phase conjugation can be utilized to compensate for channel dispersion and hence to correct for temporal pulse broadening. Specifically, a four-wave nonlinear interaction is shown to achieve pulse renarrowing. Spectral bandwidth constraints of the input pulse are presented for typical phase-conjugate interaction parameters

AN ATTEMPT AT MEASURING THE FISCAL INFLUENCE OVER ACCOUNTING OF ROMANIAN LISTED COMPANIES

This paper we seek to measure the fiscal influence over accounting on a de facto level,empirical analysis is being performed on companies listed on the Bucharest Stock Exchange (BSE)and RASDAQ market, on a sample of 210 companies. Our observation was conducted in the year2008, the variables taken in the analysis being sales as proxy for ââ¬Ëaccounting’ and income tax asmeasure for tax effects. The model we use is defined in a dynamic fashion (marginal values) sincewe believe these variables reflect the best the true variations of accounting and tax numbers.The statistical results obtained show that there is a statistically significant influence of taxationover accounting of 4%; we are not able, however, to say if this amount is large or small , insince we have no benchmark value yet. This is also the first empirical tax research paper inaccounting on Romanian data.accounting, taxation, income tax, listed companies, Romania

Image phase compensation and real-time holography by four-wave mixing in optical fibers

It is proposed that real-time holography can be performed inside multimode fibers (or optical waveguides) using four-wave optical mixing. Of particular interest is the generation of complex-conjugate replicas of input fields for image transmission and compensation of propagation distortion. A theoretical analysis and a numerical estimate are presented

Spatial convolution and correlation of optical fields via degenerate four-wave mixing

A nonlinear optical technique is described that performs, essentially instantaneously, the functions of spatial correlation and convolution of spatially encoded waves. These real-time operations are accomplished by mixing spatially dependent optical fields in the Fourier-transform plane of a lens system. The use of a degenerate four-wave mixing scheme eliminates (in the Fresnel approximation) phase-matching restrictions and (optical) frequency-scaling factors. Spatial bandwidth-gain considerations and numerical examples, as well as applications to nonlinear microscopy, are presented

Q-switched ruby laser alloying of Ohmic contacts on gallium arsenide epilayers

Ohmic contacts of AuGe have been produced on GaAs epilayers by laser alloying. The contacts possess morphological and electrical properties which are superior to those formed by conventional alloying

A LONGITUDINAL ANALYSIS REGARDING THE EVOLUTION OF PROFIT TAX REGULATIONS IN ROMANIA - AN EMPIRICAL VIEW

The study conducted a longitudinal analysis regarding Romanian profit tax regulations. Beginning with the first profit tax regulation implemented in 1991 and until now, we analyzed based on a empirical approach all changes that have occurred over time in the Romanian accounting environment. The motivation of the study conducted was based on the strong relationship between accounting and taxation in the Romanian accounting environment over time, the profit tax being one of the main items of this relation. This particular study is divided into five sections. After a short introduction and presenting the motivation of the study (section 1), in section 2 we conducted the literature review based on international and national studies regarding the profit tax regulations through the relationship between accounting and taxation. Section 3 presents a brief review of the main Romanian regulations that concerned the profit tax and the most important changes that have occurred over time. In section 4 we conducted the empirical analysis. In this section is realized a series of analysis, aiming the following: (1) the total number of regulations that have amend the main regulations presented in the previous section; (2) the type of amendments implemented over regulations (abolishment, text amendment, adding new articles or alignments); (3) the total number of amendments approved by law without modifications, respectively the total number of amendments approved on the Official Journal through Government Ordinance or Emergency Ordinance and unapproved by law. The empirical analysis conducted documented that the main shortcoming associated with the profit tax regulation is due by the multiple changes which have been subject of the 5 main profit tax regulations. The last section (section 5) consists in presenting the conclusions of the study. As main conclusion, the profit tax regulation is stable only in terms of the small number of main regulations, the large number of amendments creating difficulties in the understanding and application by practitioners.profit tax regulations, longitudinal analysis, Romania

Cardiovascular Risk Factors in Patients with Chronic Plaque Psoriasis: A Case-control Study on the Brasov County Population

Many studies have suggested that cardiovascular risk factors seem to be more common in patients with psoriasis than in the general population. In this study we aimed to determine the prevalence of cardiovascular risk factors in patients with chronic plaque psoriasis depending on the severity of disease. We conducted a prospective study in Braşov County (Romania) including 142 patients with chronic plaque psoriasis and disease duration of at least six months and 167 controls without psoriasis. The severity of psoriasis was assessed using the psoriasis area and severity index (PASI) score. Along with a thorough medical history and physical examination, serum lipid profile and fasting plasma glucose tests were carried out. The 10-year Framingham risk score (FRS) for general cardiovascular disease, which includes age, gender, total cholesterol, HDL-cholesterol, systolic blood pressure, smoking status, and diabetes mellitus, was applied.  The severity of chronic plaque psoriasis was mild in 32 patients (22.53%) and moderate to severe in 110 patients (77.47%). We found a significant higher prevalence of metabolic syndrome in the patient group compared to controls. Individual components of metabolic syndrome like waist circumference, elevated triglycerides, reduced HDL-C, impaired fasting plasma glucose, and arterial hypertension were also more prevalent in patients than in controls. Mean triglycerides, total cholesterol, LDL-cholesterol and HDL-cholesterol levels were significantly raised in patients with psoriasis when compared to controls. The 10-year FRS was significantly higher in patients with psoriasis than in controls (8.36±5.75 vs. 6.61±4.13; P&lt;0.001). FRS was higher in men (P=0.012) and in patients older than 50 years (P=0.008). According to the severity of psoriasis, FRS increases significantly from mild to moderate-to-severe psoriasis (6.82±4.48 to 8.8±6.71; P=0.003). Psoriasis, and especially moderate to severe psoriasis, seems to represent a risk factor for cardiovascular disease. Patients with psoriasis should be risk-assessed for cardiovascular diseases, and comorbidities should be actively managed.</p

Cardiovascular Risk Factors in Patients with Chronic Plaque Psoriasis: A Case-control Study on the Brasov County Population

Many studies have suggested that cardiovascular risk factors seem to be more common in patients with psoriasis than in the general population. In this study we aimed to determine the prevalence of cardiovascular risk factors in patients with chronic plaque psoriasis depending on the severity of disease. We conducted a prospective study in Braşov County (Romania) including 142 patients with chronic plaque psoriasis and disease duration of at least six months and 167 controls without psoriasis. The severity of psoriasis was assessed using the psoriasis area and severity index (PASI) score. Along with a thorough medical history and physical examination, serum lipid profile and fasting plasma glucose tests were carried out. The 10-year Framingham risk score (FRS) for general cardiovascular disease, which includes age, gender, total cholesterol, HDL-cholesterol, systolic blood pressure, smoking status, and diabetes mellitus, was applied.  The severity of chronic plaque psoriasis was mild in 32 patients (22.53%) and moderate to severe in 110 patients (77.47%). We found a significant higher prevalence of metabolic syndrome in the patient group compared to controls. Individual components of metabolic syndrome like waist circumference, elevated triglycerides, reduced HDL-C, impaired fasting plasma glucose, and arterial hypertension were also more prevalent in patients than in controls. Mean triglycerides, total cholesterol, LDL-cholesterol and HDL-cholesterol levels were significantly raised in patients with psoriasis when compared to controls. The 10-year FRS was significantly higher in patients with psoriasis than in controls (8.36±5.75 vs. 6.61±4.13; P&lt;0.001). FRS was higher in men (P=0.012) and in patients older than 50 years (P=0.008). According to the severity of psoriasis, FRS increases significantly from mild to moderate-to-severe psoriasis (6.82±4.48 to 8.8±6.71; P=0.003). Psoriasis, and especially moderate to severe psoriasis, seems to represent a risk factor for cardiovascular disease. Patients with psoriasis should be risk-assessed for cardiovascular diseases, and comorbidities should be actively managed.</p