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1.
Ravi Mosurkal 《Resonance》2001,6(10):76-86
The dream of generating electricity from sunlight in large scale at low cost may not be that far from reality in this century.
Rapidly emerging solar energy technology using low cost dye sensitized photovoltaic cells on plastics would be a real boost
for the third world countries. Though the conventional silicon solar cells are efficient in converting solar energy into electricity
until now, the non conventional solar cells based on molecular photosensitization by colored materials in wide band gap semiconductors
is a fast growing field of basic scientific and industrial research. Present state-of-the-art cells using molecular dyes shows
energy conversion efficiencies of 10–11%. In this article, we present the concept of dye-sensitized photovoltaic (DSPV) cell
and the progress in current research. The important contributions of molecular dyes that are used as photosensitizers in these
photovoltaic or solar cells are also described. 相似文献
2.
Ravi C. Paul William Swart Aixiu Monica Zhang Kenneth R. MacLeod 《Distance Education》2015,36(3):364-382
Transactional distance has been defined as barriers to students’ engagement with learning in the online environment. This research updates Zhang’s (2003) scale of transactional distance, which quantified the extent of the barriers, in light of the massive changes in today’s web-based learning environment. The resulting revised scale of transactional distance (RSTD) is a parsimonious version with 12 elements (compared to 31 original) that measure the transactional distance between student and teacher, student and student, and student and content. The RSTD has excellent factorial validity and reliability, yields better fit statistics, and is easier and less time-consuming to apply. The transactional distance values are unique predictors of student satisfaction, which is correlated to learning and persistence (a major concern with massive open online courses). This information can form the basis for a systematic approach to improving the design of today’s contemporary open, flexible, distance education courses and thus serve as a valuable tool for researchers and educators alike. 相似文献
3.
Kim Normann Andersen Rony Medaglia Ravi Vatrapu Helle Zinner Henriksen Robin GauldAuthor vitae 《Government Information Quarterly》2011,28(4):439-445
Assessing e-government responsiveness is one of the major gaps in the currently dominant e-government maturity models. While we have a relatively large pool of models focusing on technological and organizational integration from a supply side perspective, measures of responsiveness of e-government systems from a user perspective are still lacking. Replicating a study from New Zealand and Australia, this study explores the response time and quality of e-mail response in Danish local and central governments (N = 175). Despite that Denmark is high ranking in international benchmark studies, we find that one third of central government agencies did not respond at all, and close to 80% of the ministries provided none or incomplete answers. Local government responds faster and provides answers that are more complete and accurate than those provided by central government. Implications for e-government are discussed. 相似文献
4.
Ritu Sharma Mridula Mahajan Ravi Kant 《Indian journal of clinical biochemistry : IJCB》2004,19(1):10-13
Serum total lipids (cholesterol and triglyceride), lipoproteins (VLDL, LDL and HDL) and Apolipoprotein-B levels of normal
healthy individuals (n=25) and coronary artery disease patients (n=25) were estimated. The objective of the present study
was to ascertain the role of apo-B in causation and inheritance of coronary artery disease. It was observed that on an average
serum total cholesterol and triglyceride more than 200 mg/dl bring the individuals to a risk of coronary artery disease (CAD)
irrespective of the age. CAD patients achieved this value at an early age (35–45 years). Similarly VLDL and LDL levels were
found to be significantly raised in CAD patients when compared to that of age matched normal individuals, with patients achieving
risk values at an early age. HDL levels were found to be significantly lower in CAD patients as compared to normal individuals.
Serum apo-B levels were significantly raised in CAD patients as compared to age matched normal individuals. Patients with
positive family history of CAD had raised serum apo-B levels than those having negative family history. A positive coefficient
of correlation was observed between serum apo-B and LDL levels suggesting that more the number of Apo-B particles, more will
be the synthesis of atherogenic particle (LDL). Patients with negative family history had serum apo-B levels closer to those
of normal individuals and in these individuals HDL levels were found to be significantly lowered, suggesting that loss of
scavenger role of HDL could be the risk factor responsible for the causation of CAD in these patients, with negative family
history of coronary artery disease. 相似文献
5.
A. Ravi Raja G. N. Vishal Babu Geraldine Menezes T. Venkatesh 《Indian journal of clinical biochemistry : IJCB》2008,23(2):200-203
Awareness about the toxic effects of non-essential metals is still lacking in developing countries. Lead is one among them,
which ranks second in the Agency for Toxic Substances and Disease Registry’ s top 20 lists of toxic metals. Some of the herbal
medicines prepared from certain roots and leaves are known to contain this toxic metal at alarming levels. We have a case
of a person who suffered from the toxic effects of lead such as vomiting and colicky abdominal pain after consuming a herbal
remedy for Jaundice treatment. This went unrecognized initially because of the presence of multiple problems like Malaria
and Renal calculi. Lead poisoning as causative factor for anemia, vomiting and colic were confirmed only when blood lead concentration
was estimated. A combination of chelation therapy and nutritional supplementation was found to be useful in reducing the body
lead burden. 相似文献
6.
Ravi Rampersad 《British Journal of Sociology of Education》2014,35(1):73-93
Bourdieu describes capital as the political building blocks of social order that give meaning to social accumulation and consumption. Through a combination of Bourdieu’s sociology and critical race theory, this sojourn into Afro-Trinidadian boys’ achievement seeks to elucidate an approach to understanding capital as inherently raced. This is premised on an interrogation of Trinidadian society as pigmentocratically structured, where lightness is rewarded with a myriad of social advantages, and darkness denigrated as illegitimate and ‘other’. The premium placed on lighter skin is manifested interdependently in the forms of social, economic and cultural capital. As such, the operation of capital as politic not only reflects societal structures of power and domination, but importantly also contributes in the maintenance of said structures. The concept of ‘Racialised facilitative capital’ follows as inseparably both facilitator of social status and as racialised process. 相似文献
7.
In this paper we study boundary value problems for anisotropic partial differential-operator equations with parameters. The principal part of the appropriate differential operators are not self-adjoint. Several conditions for the uniform separability in weighted Banach-valued Lp-spaces are given. Sharp estimates for the resolvent of the corresponding differential operator are obtained. In particular the positivity and R-positivity of these operators are established. As an application we study the separability of degenerate DOEs, maximal regularity for degenerate abstract parabolic problem with parameters, the uniform separability of finite and infinite systems for degenerate anisotropic partial differential equations with parameters. 相似文献
8.
9.
Shashi Seth Bina Ravi H. S. Randhawa Neelam Chillar Harbans Lal 《Indian journal of clinical biochemistry : IJCB》1996,11(1):49-51
Gamma-glutamyl transpeptidase (gamma-GT) levels were estimated in the sera of patients with breast cancer and compared with those of benign breast diseases and healthy controls. Serum gamma-GT levels were found to be significantly increased in patients with breast cancer compared to the controls as well as benign breast diseases. The rise however, was nearly same in all the patients irrespective of histopathology of cancer but was directly related to tumour mass. After mastectomy the levels remained higher upto 3 months. In patients with cancer the rise in serum gamma-GT was significantly higher as compared to those with benign breast diseases. Although gamma-GT is an index of liver diseases, its high level in breast carcinoma suggests the release of the membrane bound constituents from different tissues even in carcinoma. 相似文献
10.
Yan-Hong Zhang Vydianathan Ravi Geng Qin He Dai Hui-Xian Zhang Feng-Ming Han Xin Wang Yu-Hong Liu Jian-Ping Yin Liang-Min Huang Byrappa Venkatesh Qiang Lin 《国家科学评论(英文版)》2020,7(6):964
Syngnathids (seahorses, pipefishes and seadragons) exhibit an array of morphological innovations including loss of pelvic fins, a toothless tubular mouth and male pregnancy. They comprise two subfamilies: Syngnathinae and Nerophinae. Genomes of three Syngnathinae members have been analyzed previously. In this study, we have sequenced the genome of a Nerophinae member, the Manado pipefish (Microphis manadensis), which has a semi-enclosed brood pouch. Comparative genomic analysis revealed that the molecular evolutionary rate of the four syngnathids is higher than that of other teleosts. The loss of all but one P/Q-rich SCPP gene in the syngnathids suggests a role for the lost genes in dentin and enameloid formation in teleosts. Genome-wide comparison identified a set of 118 genes with parallel identical amino acid substitutions in syngnathids and placental mammals. Association of some of these genes with placental and embryonic development in mammals suggests a role for them in syngnathid pregnancy. 相似文献