oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 69 )

2019 ( 642 )

2018 ( 724 )

2017 ( 740 )

Custom range...

Search Results: 1 - 10 of 484756 matches for " S. C. Mushini "
All listed articles are free for downloading (OA Articles)
Page 1 /484756
Display every page Item
Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions
P. Prikryl, P. T. Jayachandran, S. C. Mushini,R. Chadwick
Annales Geophysicae (ANGEO) , 2011,
Abstract: Maps of GPS phase scintillation at high latitudes have been constructed after the first two years of operation of the Canadian High Arctic Ionospheric Network (CHAIN) during the 2008–2009 solar minimum. CHAIN consists of ten dual-frequency receivers, configured to measure amplitude and phase scintillation from L1 GPS signals and ionospheric total electron content (TEC) from L1 and L2 GPS signals. Those ionospheric data have been mapped as a function of magnetic local time and geomagnetic latitude assuming ionospheric pierce points (IPPs) at 350 km. The mean TEC depletions are identified with the statistical high-latitude and mid-latitude troughs. Phase scintillation occurs predominantly in the nightside auroral oval and the ionospheric footprint of the cusp. The strongest phase scintillation is associated with auroral arc brightening and substorms or with perturbed cusp ionosphere. Auroral phase scintillation tends to be intermittent, localized and of short duration, while the dayside scintillation observed for individual satellites can stay continuously above a given threshold for several minutes and such scintillation patches persist over a large area of the cusp/cleft region sampled by different satellites for several hours. The seasonal variation of the phase scintillation occurrence also differs between the nightside auroral oval and the cusp. The auroral phase scintillation shows an expected semiannual oscillation with equinoctial maxima known to be associated with aurorae, while the cusp scintillation is dominated by an annual cycle maximizing in autumn-winter. These differences point to different irregularity production mechanisms: energetic electron precipitation into dynamic auroral arcs versus cusp ionospheric convection dynamics. Observations suggest anisotropy of scintillation-causing irregularities with stronger L-shell alignment of irregularities in the cusp while a significant component of field-aligned irregularities is found in the nightside auroral oval. Scintillation-causing irregularities can coexist with small-scale field-aligned irregularities resulting in HF radar backscatter. The statistical cusp and auroral oval are characterized by the occurrence of HF radar ionospheric backscatter and mean ground magnetic perturbations due to ionospheric currents.
GPS TEC, scintillation and cycle slips observed at high latitudes during solar minimum
P. Prikryl, P. T. Jayachandran, S. C. Mushini, D. Pokhotelov, J. W. MacDougall, E. Donovan, E. Spanswick,J.-P. St.-Maurice
Annales Geophysicae (ANGEO) , 2010,
Abstract: High-latitude irregularities can impair the operation of GPS-based devices by causing fluctuations of GPS signal amplitude and phase, also known as scintillation. Severe scintillation events lead to losses of phase lock, which result in cycle slips. We have used data from the Canadian High Arctic Ionospheric Network (CHAIN) to measure amplitude and phase scintillation from L1 GPS signals and total electron content (TEC) from L1 and L2 GPS signals to study the relative role that various high-latitude irregularity generation mechanisms have in producing scintillation. In the first year of operation during the current solar minimum the amplitude scintillation has remained very low but events of strong phase scintillation have been observed. We have found, as expected, that auroral arc and substorm intensifications as well as cusp region dynamics are strong sources of phase scintillation and potential cycle slips. In addition, we have found clear seasonal and universal time dependencies of TEC and phase scintillation over the polar cap region. A comparison with radio instruments from the Canadian GeoSpace Monitoring (CGSM) network strongly suggests that the polar cap scintillation and TEC variations are associated with polar cap patches which we therefore infer to be main contributors to scintillation-causing irregularities in the polar cap.
Kinetics of substitution of cis-bis(malonato)diaquochromate(III) with glycine, DL-alanine and DL-phenylalanine
VSR Mushini, VA Ramam, VM Rao
Bulletin of the Chemical Society of Ethiopia , 2009,
Abstract: The kinetics of interaction between amino acids such as glycine, DL-alanine and DLphenylalanine and cis-bis(malonato)diaquochromate(III) has been studied spectrophotometrically as a function of [glycine], [DL-alanine] and [DL-phenylalanine]. The effect of pH, temperature and substrate is also studied. The substrate exists predominantly as the diaquospecies and amino acids (glycine, DL-alanine and DL-phenylalanine) as the zwitterion at the experimental conditions. The substitution reaction has been found to proceed via two steps: amino acid dependent and amino acid independent paths indicating that the substitution reaction occurs through associative interchange (Ia) mechanism in the amino acid dependent path and the dissociative mechanism in the independent path, showing the higher reactivity of single ended malonate complex.
Kinetics of substitution of cis-bis(malonato)diaquochromate(III) with glycine, DL-alanine and DL-phenylalanine in alkaline medium
Venkata Subba Rao Mushini, V. Ananta Ramam, V. Muralidhara Rao
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: The kinetics of interaction among amino acids such as glycine, DL-alanine and DL-phenylalanine and cis-bis(malonato)diaquochromate(III) has been studied spectrophotometrically as a function of [glycine], [DL-alanine] and [DL-phenylalanine] in alkaline medium. The effect of pH, temperature and substrate was also studied. The substitution reaction has been found to proceed via two steps: amino acid dependent and amino acid independent path. In this process, it indicated that the substitution reaction occurs through an Ia mechanism in the amino acid dependent path and a dissociative mechanism in the independent path, showing the higher reactivity of single ended malonate complex. KEY WORDS: Substitution, cis-bis(Malonato)diaquochromate(III), Amino acids, Alkaline medium Bull. Chem. Soc. Ethiop. 2011, 25(1), 103-110.
Kinetics of substitution of cis-bis(malonato)diaquochromate(III) with glycine, DL-alanine and DL-phenylalanine in alkaline medium
Venkata Subba Rao Mushini,V. Ananta Ramam,V. Muralidhara Rao
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: The kinetics of interaction among amino acids such as glycine, DL-alanine and DL-phenylalanine and cis-bis(malonato)diaquochromate(III) has been studied spectrophotometrically as a function of [glycine], [DL-alanine] and [DL-phenylalanine] in alkaline medium. The effect of pH, temperature and substrate was also studied. The substitution reaction has been found to proceed via two steps: amino acid dependent and amino acid independent path. In this process, it indicated that the substitution reaction occurs through an Ia mechanism in the amino acid dependent path and a dissociative mechanism in the independent path, showing the higher reactivity of single ended malonate complex.
Kinetics of substitution of cis-bis(malonato)diaquochromate(III) with glycine, DL-alanine and DL-phenylalanine
Venkata Subba Rao Mushini,V. Ananta Ramam,V. Muralidhara Rao
Bulletin of the Chemical Society of Ethiopia , 2009,
Abstract: The kinetics of interaction between amino acids such as glycine, DL-alanine and DL-phenylalanine and cis-bis(malonato)diaquochromate(III) has been studied spectrophotometrically as a function of [glycine], [DL-alanine] and [DL-phenylalanine]. The effect of pH, temperature and substrate is also studied. The substrate exists predominantly as the diaquospecies and amino acids (glycine, DL-alanine and DL-phenylalanine) as the zwitterion at the experimental conditions. The substitution reaction has been found to proceed via two steps: amino acid dependent and amino acid independent paths indicating that the substitution reaction occurs through associative interchange (Ia) mechanism in the amino acid dependent path and the dissociative mechanism in the independent path, showing the higher reactivity of single ended malonate complex.
An EPQ Model with Imperfect Production Systems with Rework of Regular Production and Sales Return  [PDF]
C. Krishnamoorthi, S. Panayappan
American Journal of Operations Research (AJOR) , 2012, DOI: 10.4236/ajor.2012.22026
Abstract: The Economic Production Quantity (EPQ) model is commonly used by practitioners in the fields of production and inventory management to assist them in making decision on production lot size. The common assumptions in this model are that all units produced are perfect and shortages are not allowed. But, in real situation the defective items will be produced in each cycle of production and shortages and scrap are possible. These assumptions will underestimate the actual required quantity. Hence, the defective items can not be ignored in the production process. Rework process is necessary to convert those defective into finished goods. This study proposes EPQ model that incorporates both imperfect production quality and falsely not screening out a proportion of defects, thereby passing them on to customers, resulting in defect sales returns. To active this objective a suitable mathematical model is developed and the optimal production lot size which minimizes the total cost is derived. An illustrative example is provided and numerically verified. The validation of result in this model was coded in Microsoft Visual Basic 6.0.
Influences on the study of Vulvar Anatomy and Disease  [PDF]
Ian S. C. Jones
Open Journal of Obstetrics and Gynecology (OJOG) , 2012, DOI: 10.4236/ojog.2012.23045
Abstract: The study of Gynaecology over the years has been influenced by the culture and social attitudes of society to the body as a whole and to the genital organs in particular. Variations in these attitudes between different cultures and at different times have influenced the subsequent rate of progress in the study of the vulva and its diseases.
Melanosis of the vulva: A long-term follow-up from Brisbane, Australia  [PDF]
Ian S. C. Jones
Open Journal of Obstetrics and Gynecology (OJOG) , 2012, DOI: 10.4236/ojog.2012.23051
Abstract: Object: To determine if vulvar melanosis progressed to melanoma over a period of 20 years or more. Methods: In 2010 the hospital records from the Royal Brisbane Hospital Vulvar Clinic between 1976 and 1988 were reviewed and cross checked with the state wide Queensland Centre for Gynaecological Cancer (QCGC) data base to determine if any patient had been lost to follow up and subsequently developed a vulvar melanoma. Data collected were stored and analysed using the computer software Statistical Package for the Social Sciences (SPSS) 11.0. Results: None of the 12 patients developed vulval melanoma in the years up to 2010. Conclusion: In this small group, followed for more than 20 years, melanosis was not a precursor of melanoma. One patient, who attended the Vulvar Clinic but was not included in this melanosis study, was found to have co-existing melanosis well away from her melanoma in situ and malignant melanoma at presentation. It was not possible to determine if these findings represented a progression of the benign to malignant. Biopsy of abnormal hyper pigmented vulvar skin is recommended. Current knowledge suggests that vulvar melanosis is a benign condition but to be on the safe side follow up of all hyper pigmented vulval lesions to detect early malignant change is recommended.
A review of conditions altering the permanent appearance of the vulva  [PDF]
Ian S. C. Jones
Open Journal of Obstetrics and Gynecology (OJOG) , 2012, DOI: 10.4236/ojog.2012.24078
Abstract: This article is aimed at providing information on variations in the clinical appearance of the vulva. The appearance of the vulva can be altered by reversible or permanent conditions both of which may result in minor or major changes. Reversible conditions include those associated with infections or acute trauma which results in distortion of the vulva. Some permanent changes are caused by life threatening conditions which are present at birth whereas others develop more slowly or as the result of a deliberate act either traditional female surgery or surgery performed by a registered medical practitioner. To the inexperienced practitioner changes from the normal vulvar appearance can be confusing. The aim of this article is to highlight and categorise changes that can affect the appearance of the vulva. Whatever the presentation the importance of obtaining a detailed history and performing an appropriate, sensitive and thorough examination can not be over emphasised.
Page 1 /484756
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.