2,474 research outputs found
Constraining the Variation in Fine-Structure Constant Using SDSS DR8 QSO Spectra
We report a robust constrain on the possible variation of fine-structure
constant, alpha = e^2/(hbar*c), obtained using O III 4959,5007, nebular
emission lines from QSOs. We find Delta-alpha/alpha=-(2.1 +/- 1.6) x 10^(-5)
based on a well selected sample of 2347 QSOs from Sloan Digital Sky Survey Data
Release 8 with 0.02 < z < 0.74. Our result is consistent with a non-varying
alpha at a level of 2 x 10^(-5) over approximately 7 Gyr. This is the largest
sample of extragalactic objects yet used to constrain the variation of alpha.
While this constraint is not as stringent as those determined using
many-multiplet method it is free from various systematic effects. A factor of ~
4 improvement in Delta-alpha/alpha achieved here compared to the previous study
(Bahcall et al. 2004) is just consistent with what is expected based on a
factor of 14 times bigger sample used here. This suggests that errors are
mainly dominated by the statistical uncertainty. We also find the ratio of
transition probabilities corresponding to the O III 5007 A and 4959 A lines to
be 2.933+/-0.002, in good agreement with the National Institute of Standards
and Technology measurements.Comment: 5 pages, 3 figures; Accepted for publication in MNRAS Lette
Asexual reproduction without a mycelial phase in Neurospora.
Asexual reproduction without a mycelial phase in Neurospora
REITs and Idiosyncratic Risk
This study examines various determinants of idiosyncratic risk from the perspective of un-diversified REIT investors, managers holding options, other option holders, and arbitrageurs. Since real estate investment trusts (REITs) enjoy a unique organizational structure and tax status, the relevant determinants derived from the two-stage regression model are different from other industrial firms. Results suggest that efficiency, liquidity and earnings variability are the important determinants of idiosyncratic risk, whereas size and capital do not
SOLID AS SOLVENTĆ¢ā¬- NOVEL SPECTROPHOTOMETRIC ANALYSIS OF NORFLOXACIN TABLETS USING PHENOL AS SOLVENT
Commonly used organic solvents for spectrophotometric analysis of water insoluble drugs include methanol, ethanol, chloroform, benzene, dichloromethane, dimethyl formamide, acetonitrile, ethyl acetate, toluene, carbon tetrachloride, acetone, hexane etc. The main drawbacks of organic solvents include high cost, toxicity and pollution. Organic solvents have innumerous adverse effects caused by single exposure like dermatitis, headache, drowsiness, nausea, eye irritation and long term exposure causes serious effects such as neurological disorders, chronic renal failure, liver damage, necrosis, mutagenesis disorder. They should be replaced by other eco-friendly alternative sources. The present investigation is an attempt to show that solids can also be wisely used to act as solvent precluding the use of organic solvents. In a separate study, author has attempted soxhelation using phenol as solvent. The vapours of boiling phenol got condensed in extraction chamber to effect the extraction of active constituents from powder of crude drugs. The main objective of the present study is to demonstrate the solvent action of solids. Solid excipients can nicely be employed as solubilizers in the development of pharmaceutical dosage forms in solution form of poorly soluble drugs (mixed solvency concept). Present study describes the application of solvent character of melted phenol (at 50-60ĆĀ°C) for spectroscopic estimation of norfloxacin tablets. Solubility of norfloxacin in distilled water is 0.88 mg/ml. More than 100 mg of nofloxacin dissolves in one gram of melted phenol (at 50-60ĆĀ°C). In the present investigation, melted phenol (at 50-60ĆĀ°C) was utilized to extract out (dissolve) the drug from powder of norfloxacin tablets. Distilled water was used for dilution purpose. Absorbances of standard solutions containing 5, 10, 15, 20, and 25 ĆĀµg/ml were noted at 324 nm against reagent blanks to obtain calibration curve. Proposed method is novel, economic, eco-friendly, rapid, free from toxicity of organic solvent, accurate and reproducible. Recovery studies and statistical data proved the accuracy, reproducibility and precision of the proposed method. The presence of tablet excipients and phenol did not interfere in the spectrophotometric estimation at 324 nm
Phenotypic lag in macroconidia of N. crassa his-3\u3csup\u3e+\u3c/sup\u3e transsformants and its implication in estimation of nuclear ratios
A majority of prototrophic macroconidia of two of the three histidine transformants of Neurospora crassa tested required histidine for germination. This condition led to an underestimation of the proportion of his-3+ macroconidia in the samples and wronged the estimation of ratio of his-3+/ his-3 nuclei by direct plating method. To correctly estimate nuclear ratio, a sample of colonies from histidine-supplemented plating medium was transferred to histidine drop-out slants and the proportion of auxotrophic and prototrophic colonies was determined from their growth response. The amino acid requirement by prototrophic macroconidia was not specific, was limited to colony formation and was not due to low endogenous content of amino acids
A simple method of obtaining pure microconidia in Neurospora crassa
In order to examine the nuclear types that may be carried in strains of Neurospora collected from nature, we desired a method of selectively inducing microconidiation in mycelia whereby uninucleate microconidia could be obtained for isolating homokaryotic derivatives. We have devised a simple and highly effective method of obtaining pure microconidia from wild-collected strains as well as from N. crassa 74-OR23-1VA
Long-lasting UV protection and mosquito repellent finish on bamboo/tencel blended fabric with microencapsulated essential oil
In this study , bamboo/tencel 50:50 blended fabric has been used for microencapsulation finishing by essential oil combination using exhaustion method in order to enhance the wash durability of the fabric. The three shell materials, namely sodium alginate, Acacia arabica and Moringa oleifera gum and three core materials like thyme oil, cypress oil and grapefruit oils in combination of 2:1:1 have been used. Then the fabrics are tested for functional properties like UV protection and mosquito repellency, and also the fabric is analyzed for allergic test. The result shows that the Moringa oleifera shell finished fabric has very good activity in both the functional property and there is no allergic reaction found. The durability can also be achieved up to 30 washes by using Moringa oliefera gum material as compared to other two
Dynamics of Team Teaching and Research in a Management School: Learning and Imperatives
This paper discusses the experience of team teaching to address the issues of integration of academic inputs by bringing multi-disciplinary perspective together and thereby enhance learning experience of participants. The paper delves on the process, events and outcome of team teaching by four faculty members at IIM Ahmedabad who collaborated in teaching, writing cases, and doing research for a period of more than three years. The experience has been summarized using the following dimensions: need for team-teaching, existing mechanisms and barriers, opportunities and potential, imperatives, fall-outs and challenges experienced in the process. The cohesion, trust and mutual respect are key imperatives. The other factors contributing to the success of team-teaching are strong felt need by the members for integration in programmes, complementary skills and experiences of team members, frequent programmes with integrated components that provided continuous opportunities for learning, co-location of the instructors, and off-site programmes that provided opportunities for close get-togethers. The autonomy granted by the institution to instructors and co-coordinators to design and execute learning opportunities was also instrumental in the success. In an environment where the rule of the game is individualism, forming teams creates fears of loss of importance and recognition. The experience shows that the competency of the members and the overall effectiveness of the tasks are strengthened if the team believes in āreciprocating interdependenceā. This can be possible only if members allow themselves opportunities to experiment, improvise and review
Use of microconidia for testing the genetic purity of Neurospora stocks
Uninucleate microconidia have been used to check the purity of laboratory stocks of Neurospora. Stock cultures of N. crassa and N. intermedia become heterokaryotic due to spontaneous mutation
- ā¦