Prediction theory in Hilbert Spaces: Operator-valued Szego Theory

In this paper, we extend some classical results of the Szego theory of orthogonal polynomials on the unit circle to the infinite-dimensional case

Effect of Hydrogen on Pristine Amorphous V2O5 Thin Film

Sequentially deposited layer by layer up to five vanadium oxide film is deposited on glass and silica substrates at 300 k by vacuum thermal evaporation technique. The deposited samples subjected to reduction process in the preparation situe by hydrogen gas at 473k for 10 minutes and 573 k for 10, 20 minutes. The XRD investigation of the samples demonstrates that the pristine sample is amorphous while those reduced are crystalline. The existed phases in virgin samples are educated by Raman spectroscopy which indicates the single V2O5 phase. The different phases in the reduced sample are identified by analyzing their XRD patterns. The electrical resistance of the reduced samples is measured as a function of temperature during heating and cooling cycles. The transition temperature from semiconducting to metal state is defined by the derivative of dR/d

New heat treatment to prepare high quality polycrystalline and single crystal MgB2 in single process

We report here on a new heat treatment to prepare both dense polycrystalline and single crystal MgB2 high quality samples in one single process. Resistivity measurements for polycrystalline part of the sample gives a residual resistivity ratio RRR=16.6 and a very low normal state resistivity rho(40K)= 0.28 microOhmcm. Both SEM and SQUID study on polycrystals reveal the high quality, dense character and well coupling of grain boundaries. On the other hand, the high quality single crystals have a unique shape that resembles the hexagonal crystal structure. SQUID measurements reveals very weak flux pinning character implying our single crystals to be very clean. In this study, we conclude that heat treatment is playing a major rule on the characteristics of both polycrystalline and single crystal MgB2. Samples are thoroughly characterized by x-ray, resistivity, dc SQUID and SEM

Ramanovi i fotoluminescentni spektri čistih i kositrom obogaćenih tankih slojeva CdS pripremljenih prskanjem i pirolizom

Thin films of CdS, pure and enriched with different concentrations of tin up to 6%, were prepared by the spray pyrolysis technique. All samples were prepared at the deposition temperature of 420 ◦C. The XRD diagnostic data of the investigated samples revealed the polycrystalline nature of the as-deposited samples. The main characteristic peaks of CdS appeared in both pure and enriched films prepared by all used methods. The enrichment of Sn has no effect on positions of the characteristic peaks. The observed effect of Sn enrichment is the change in peak broadening which increases with the increase of Sn concentration. The thickness values ranged from 0.65 up to 1.15 µm. The samples of pure CdS show a sharp absorption edge at about 2.43 eV. The absorption coefficient α of the investigated samples was calculated from transmission and reflection spectra. Photoluminescence measurements show red emission band of the as-deposited samples, which was quenched by Sn incorporation. This band is ascribed to the excess of Cd which was checked by the energy dispersive X-ray (EDX) spectrometry. Raman spectra of samples with different concentrations of Sn were studied. They show remarkable increase of intensity when increasing the film thickness and decreasing the Sn concentration.Metodom prskanja i pirolize pripremali smo čiste i do 6% kositrom obogaćene tanke slojeve CdS. Sve uzorke smo pripremali na temperaturi polaganja od 420 ◦C. XRD spektri ispitivanih uzoraka pokazuju polikristaliničnu strukturu. Glavni karakteristični vrhovi CdS vide se i u čistim i u obogaćenim uzorcima pripremljenim primijenjenim metodama. Obogaćenje kositrom nema utjecaja na položaje karakterističnih vrhova. Međutim, javlja se proširenje vrhova koje se povećava pri povećanim koncentracijama kositra. Izmjerene i izračunate debljine slojeva su u skladu. Debljine slojeva bile su između 0.65 i 1.15 µm. Uzorci CdS pokazuju oštar apsorpcijski rub na oko 2.43 eV. Apsorpcijske koeficijente α ispitivanih uzoraka smo izveli iz transmisijskih i refleksijskih spektara. Mjerenja fotoluminescencije pokazuju crvenu emisijsku vrpcu koja trne dodavanjem kositra. Ta se vrpca tumači viškom Cd što smo potvrdili disperzivnom rendgenskom spektrometrijom (EDX). Proučavali smo i Ramanove spektre uzoraka s raznim koncentracijama kositra. Oni pokazuju snažan porast intenziteta za slojeve veće debljine i manje koncentracije kositra

A Comparative Study of Blood Levels of Manganese, Some Macroelements and Heavy Metals in Obese and Non-Obese Polycystic Ovary Syndrome Patients

Polycystic ovary syndrome (PCOS) is a prevalent condition in women of reproductive age. It is characterized by androgen excess and chronic anovulation. Some trace elements, macroelements, and heavy metals have been linked to pathophysiological mechanisms of PCOS . To study the alterations in the serum levels of the trace element manganese (Mn), some macroelements, magnesium(Mg) and calcium (Ca), and the heavy metals cadmium (Cd) and lead (Pb), in obese and non-obese PCOS patients; and the association of these alterations with some of the hormonal changes occurring in PCOS. The study was carried out at Kamal Al-Samarrai Hospital (Center for Infertility treatment and in vitro Fertilization "IVF") Baghdad- Iraq. Eighty-two women were enrolled in the study. Fifty-four of them were diagnosed by a specialist gynecologist as PCOS patients; they were subdivided into two subgroups according to their body mass index (BMI); twenty-seven obese PCOS patients with BMI > 30 kg/m2, and another twenty seven non obese patients PCOS with BMI 30kg/m2, and fourteen non obese women with BMI <30 kg/m2. Blood lead and cadmium levels were significantly higher in both of the obese and the non-obese PCOS groups, than in their corresponding control groups. While, serum magnesium, calcium and manganese levels were significantly lower in both of the obese and the non-obese PCOS groups, as compared to their corresponding control groups. The results revealed no significant difference in the levels of the measured elements, between the obese PCOS group and the non-obese PCOS group. The serum FSH levels was significantly lower in obese PCOS patients than in the obese and non-obese control groups. There was a positive correlation between blood lead and serum TSH levels in non-obese PCOS women; and between serum total testosterone and cadmium levels in obese PCOS women. Finally, there was negative correlation between serum magnesium and serum LH levels in non-obese PCOS women. the study has demonstrated higher blood levels of lead and cadmium; and lower serum levels of magnesium, calcium and manganese in PCOS groups than control subject. There were no significant differences between obese PCOS women and non-obese PCOS women in the levels of the studied hormones, elements and heavy metals

Antioxidant activities and flavonoid contents of selected plants belonging to Family Loranthaceae

The methanolic extract of three parasitic plants belonging to family Loranthaceae (Plicosepalus acacia, Plicosepalus curviflorus and Phragmanthera austro arabica) were investigated for their antioxidant activity. The free radical and nitrogen oxide scavenging abilities were evaluated using diphenyl-1-picrylhydrazyl (DPPH), and Griess reagent was used to determine the total antioxidant activity. The three extracts showed comparable activities. The three activities ranged from 18 to 56% of the activity of standard ascorbic. The total flavonoid contents were determined and calculated in terms of quercetin which was detected in all the examined extracts. The quercetin concentration was determined using high performance thin layer chromatography using CHCl3 : MeOH : glacial acetic acid (8.5: 1.5: 0.1) for development. The maximum sensitivity was obtained when the plates were scanned at 360 nm. The concentration of quercetin varied from 0.157 (P. austro arabica) to 0.062 g% (P. acacia) and P. curviflorus contained 0.115 g% w/w quercetin. All validation parameters were found to be satisfactory regarding accuracy, precision, limits of detection and quantitation.Key words: Loranthaceae, antioxidant, spectrophotometry, high performance thin layer chromatography (HPTLC), flavonoids, quercetin, ascorbic acid

Modeling of Seismic Signatures of Carbonate Rock Types

Carbonate reservoirs of different rock types have wide ranges of porosity and permeability, creating zones with different reservoir quality and flow properties. This research addresses how seismic technology can be used to identify different carbonate rock types for characterization of reservoir heterogeneity. I also investigated which seismic methods can help delineate thin high-permeability (super-k) layers that cause early water breakthroughs that severely reduce hydrocarbon recovery. Based on data from a Middle East producing field, a typical geologic model is defined including seal, a thin fractured layer, grainstone and wackestone. Convolutional, finite difference, and fluid substitution modeling methods are used to understand the seismic signatures of carbonate rock types. Results show that the seismic reflections from the seal/fractured-layer interface and the fractured-layer/grainstone interface cannot be resolved with conventional seismic data. However, seismic reflection amplitudes from interfaces between different carbonate rock types within the reservoir are strong enough to be identified on seismic data, compared with reflections from both the top and bottom interfaces of the reservoir. The seismic reflection amplitudes from the fractured-layer/grainstone and the grainstone/wackestone interfaces are 17% and 23% of those from the seal/fracturedlayer interface, respectively. By using AVO analysis, it may be possible to predict the presence of the fractured layer. It is observed that seismic reflection amplitude resulting from the interference between the reflections from overburden/seal and seal/fractured-layer does not change with offset. The thin super-k layer can also be identified using fluid substitution method and time-lapse seismic analysis. It shows that this layer has 5% increase in acoustic impedance after oil is fully replaced by injecting water in the layer. This causes 11% decrease and 87% increase in seismic reflection amplitudes from the seal/fractured-layer interface and the fractured-layer/grainstone interface after fluid substitution, respectively. These results show that it is possible to predict carbonate rock types, including thin super-k layers, using their seismic signatures, when different seismic techniques are used together, such as synthetic wave modeling, AVO, and time-lapse analysis. In future work, the convolutional model, AVO analysis, and fluid substitution could be applied to real seismic data for field verification and production monitoring