533 research outputs found
Light transmission through and its complete stoppage in an ultra slow wave optical medium
Light Wave transmission -- its compression, amplification, and the optical
energy storage -- in an Ultra Slow Wave Medium (USWM) is studied analytically.
Our phenomenological treatment is based entirely on the continuity equation for
the optical energy flux, and the well known distribution-product property of
Dirac delta-function. The results so obtained provide a clear understanding of
some recent experiments on light transmission and its complete stoppage in an
USWM.
Keywords : Ultra slow light, stopped light, slow wave medium, EIT.Comment: (single-column 5pages PDF). Simple class-room phenomenological model
of stopped light. Comments most welcom
Speech Emotion Recognition System
Speech Emotion Recognition (SER) is a research topic which has a wide range of applications. The features of speech such as, Mel Frequency cepstrum coefficients (MFCC ) are extracted which are uttered in the speech. To classify different emotional states such as boredom, happiness, sadness, neutral, anger, from various emotional sound tracks from a database containing emotional speech SVM is used as classifier. SVM is used for classification of emotions. The accuracy obtained in SVM is very much higher.
DOI: 10.17762/ijritcc2321-8169.15057
Risk factor assessment in South African Black patients presenting with acute myocardial infarction at R.K. Khan Hospital, Durban
Objective: To assess various risk factors in Black South African patients presenting with acute myocardial infarction (AMI) to the Coronary Care Unit (CCU) at R.K. Khan Hospital, Durban, South Africa. Methods and results: The study population was recruited from consecutive patients from a multi-ethnic background with a diagnosis of AMI over a 4 year period (2008 - 2012). Only patients who were of Black South African origin (n=94) were eligible for analysis. Demographic data stored in an electronic database were extracted from all patients. The mean age of the participantswas 54.3 ± 11.0 years of whom 85% were males. The majority presented with ST elevation myocardial infarction (STEMI) (83%) whilst 17% had Non ST elevation myocardial infarction (NSTEMI). Smoking (48%) and hypertension (46%) were the most commonly observed risk factors. Thirty six percent of patients developed one or more major adverse cardiac events (MACE). Recurrence of infarction and death occurred more frequently in females compared to males (14% vs. 2%, p=0.04). No signifi cant difference in MACE was found between patients who were human immunodefi ciency virus (HIV) positive (18%) compared to those who were HIV negative (82%). Metabolic syndrome, as defi ned by the International Diabetes Federation (IDF) criteria, was found in 35 (45%) of patients. The number of patients presenting with hypertension and diabetes was signifi -cantly higher in our study compared to the INTERHEART Africa study (73% vs. 50%, p<0.01; and 40% vs. 24%, p<0.01). Conclusion: South African Blacks have multiple risk factors, similar to other ethnic groups in the country, which contribute to the development of AMI. Recurrence of infarction and death occurred more frequently in females compared to males. In addition to conventional risk factors for CAD, an increased heart rate, STEMI, obesity, family history of cerebrovascular disease and hyperuricaemia are strongly associated with the presence of MACE
Effect of Injected Noise on Electromagnetically Induced Transparency and Slow Light
We have examined theoretically the phenomenon of Electromagnetically Induced
Transparency (EIT) in a three-level system operating in the
lambda-configuration in presence of an externally injected noise coupling the
ground level to the intermediate (metastable) level. The changes in the depth
and the width of the induced transparency and the slowing down of the probe
light have been calculated as function of the probe detuning and the strength
of the injected noise. The calculations are within the rotating-wave
approximation (RWA). Our main results are the reduction and the broadening of
the EIT with increasing strength of the injected noise, and a reduction in the
slowing down of group velocity of the probe-laser beam. Thus, the injected
semi-classical noise, unlike the quantum-dynamical noise associated with the
spontaneous emission, is not effectively cancelled by the EIT mechanism.Comment: 6 Pages, 7 Figure
Metagenomics — A Technological Drift in Bioremediation
Nature has its ways of resolving imbalances in its environment and microorganisms are one of the best tools of nature to eliminate toxic pollutants. The process of eliminating pollutants using microbes is termed Bioremediation. Metagenomics is a strategic approach for analysing microbial communities at a genomic level. It is one of the best technological upgradation to bioremediation. Identification and screening of metagenomes from the polluted environments are crucial in a metagenomic study. This chapter emphasizes recent multiple case studies explaining the approaches of metagenomics in bioremediation in different contaminated environments such as soil, water etc. The second section explains different sequences and function-based metagenomic strategies and tools starting from providing a detailed view of metagenomic screening, FACS, and multiple advanced metagenomic sequencing strategies dealing with the prevalent metagenomes in bioremediation and giving a list of different widespread metagenomic organisms and their respective projects. Eventually, we have provided a detailed view of different major bioinformatic tools and datasets most prevalently used in metagenomic data analysis and processing during metagenomic bioremediation
A Multiferroic Ceramic with Perovskite Structure: La0.5Bi0.5Mn0.5Fe0.5O3.09
ABO3 perovskite multiferroic La0.5Bi0.5Mn0.5Fe0.5O3.09 where the B-site
cations is responsible for the magnetic properties and the A-site cation with
lone pair electron is responsible for the ferroelectric properties was
synthesized at normal conditions. This oxide exhibits a ferromagnetic
transition around 240 K with a well defined hysteresis loop, and a significant
reversible remnant polarization below 67K similar to ferroelectric behavior.
The magnetic interaction is interpreted by the ferromagnetic Fe3+-O-Mn3+ and
antiferromagnetic Fe3+(Mn3+)-O-Fe3+(Mn3+) interactions competed each other,
whereas the ferroelectricity is predominantly due to the polar nature
introduced by the 6s2 lone pair of Bi3+ cationsComment: Submitted to Applied Physics Letters, 7 pages, 3 figure
SYNTHESIS, CHARACTERIZATION AND IN VITRO MICROBIAL EVALUATION OF REGIOISOMERS OF ALLYL PHENYL ETHERS DERIVED 1, 2, 4-TRIAZOLES
Objective: Synthesis and antimicrobial evaluation of regioisomers of allyl phenyl ethers derived 1, 2, 4-triazoles.
Methods: A series of new 1,2,4-triazole derivatives of allyl phenyl ethers were synthesized by reacting a mixture of regio isomers 1-(3-bromo-2-methoxypropoxy)-arene and 1-(2-bromo-3-methoxypropoxy)-arene with 1,2,4-triazole in presence of K2CO3 and DMF at 80oC in good yields. Allyl phenyl ethers 1(a-f) were synthesized by refluxing the substituted phenols with allyl bromide in the presence of K2CO3 and acetone in excellent yields. The newly synthesized compounds were characterized by IR, 1HNMR, Mass spectral studies and elemental analysis. These compounds were also screened for their In-vitro antibacterial and antifungal activities.
Results: Allyl phenyl ethers derived 1,2,4-triazol derivatives were synthesized in good yields.
Conclusion: Preliminary results revealed that some of the synthesized compounds were showed promising antibacterial and antifungal activity
Ethyl 2-[N-(2-formylphenyl)benzenesulfonamido]acetate
In the molecule of the title compound, C17H17NO5S, the two aromatic rings are oriented at an angle of 30.13 (10)°. The ethyl acetate group assumes an extended conformation. Molecules are linked into C(7) chains running along the a axis by intermolecular C—H⋯O hydrogen bonds, and the chains are crosslinked via C—H⋯π interactions, with the sulfonyl-bound phenyl ring acting as an acceptor
RNAseq reveals hydrophobins that are involved in the adaptation of aspergillus nidulans to lignocellulose
Background
Sugarcane is one of the world’s most profitable crops. Waste steam-exploded sugarcane bagasse (SEB) is a cheap, abundant, and renewable lignocellulosic feedstock for the next-generation biofuels. In nature, fungi seldom exist as planktonic cells, similar to those found in the nutrient-rich environment created within an industrial fermenter. Instead, fungi predominantly form biofilms that allow them to thrive in hostile environments.
Results
In turn, we adopted an RNA-sequencing approach to interrogate how the model fungus, Aspergillus nidulans, adapts to SEB, revealing the induction of carbon starvation responses and the lignocellulolytic machinery, in addition to morphological adaptations. Genetic analyses showed the importance of hydrophobins for growth on SEB. The major hydrophobin, RodA, was retained within the fungal biofilm on SEB fibres. The StuA transcription factor that regulates fungal morphology was up-regulated during growth on SEB and controlled hydrophobin gene induction. The absence of the RodA or DewC hydrophobins reduced biofilm formation. The loss of a RodA or a functional StuA reduced the retention of the hydrolytic enzymes within the vicinity of the fungus. Hence, hydrophobins promote biofilm formation on SEB, and may enhance lignocellulose utilisation via promoting a compact substrate-enzyme-fungus structure.
Conclusion
This novel study highlights the importance of hydrophobins to the formation of biofilms and the efficient deconstruction of lignocellulose
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