oalib

OALib Journal期刊

ISSN: 2333-9721

费用:99美元

投稿

时间不限

2018 ( 3 )

2017 ( 185 )

2016 ( 322 )

2015 ( 7570 )

自定义范围…

匹配条件: “Partha P. Kundu” ,找到相关结果约201318条。
列表显示的所有文章,均可免费获取
第1页/共201318条
每页显示
Raman based imaging in biological application- a perspective
Partha P. Kundu,Chandrabhas Narayana
Journal of Medical and Allied Sciences , 2012,
Abstract: Imaging by means of Raman spectroscopy has emerged as a powerful technique in the study of various chemical processes occurring in biology. This technique is non-invasive, label-free, capable of providing molecular identity and can be performed in robust conditions. However, one major drawback is its inherently weak signal. The ways to overcome this issue is to use Raman based methods e.g. Resonance Raman Spectroscopy (RRS), Surface Enhanced Raman Spectroscopy (SERS), Tip Enhanced Raman Spectroscopy (TERS). In this review, we gave a brief introduction of all these methods, with special emphasis on their recent advances and applications in various fields of life science.
Outbreak of Mass Sociogenic Illness in a School Feeding Program in Northwest Bangladesh, 2010
Farhana Haque, Subodh Kumar Kundu, Md Saiful Islam, S. M. Murshid Hasan, Asma Khatun, Partha Sarathi Gope, Zahid Hayat Mahmud, A. S. M. Alamgir, M. Sirajul Islam, Mahmudur Rahman, Stephen P. Luby
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0080420
Abstract: Background In 2010, an acute illness outbreak was reported in school students eating high-energy biscuits supplied by the school feeding programme in northwest Bangladesh. We investigated this outbreak to describe the illness in terms of person, place and time, develop the timeline of events, and determine the cause and community perceptions regarding the outbreak. Methods We defined case-patients as students from affected schools reporting any two symptoms including abdominal pain, heartburn, bitter taste, and headache after eating biscuits on the day of illness. We conducted in-depth interviews and group discussions with students, teachers, parents and community members to explore symptoms, exposures, and community perceptions. We conducted a questionnaire survey among case-patients to determine the symptoms and ascertain food items eaten 12 hours before illness onset, and microbiological and environmental investigations. Results Among 142 students seeking hospital care, 44 students from four schools qualified as case-patients. Of these, we surveyed 30 who had a mean age of 9 years; 70% (21/30) were females. Predominant symptoms included abdominal pain (93%), heartburn (90%), and bitter taste (57%). All students recovered within a few hours. No pathogenic Vibrio cholerae, Shigella or Salmonella spp. were isolated from collected stool samples. We found no rancid biscuits in schools and storage sites. The female index case perceived the unusually darker packet label as a “devil’s deed” that made the biscuits poisonous. Many students, parents and community members reported concerns about rumors of students dying from biscuit poisoning. Conclusions Rapid onset, followed by rapid recovery of symptoms; female preponderance; inconsistent physical, microbiological and environmental findings suggested mass sociogenic illness rather than a foodborne or toxic cause. Rumours of student deaths heightening community anxiety apparently propagated this outbreak. Sharing investigation results and reassuring students and parents through health communication campaigns could limit similar future outbreaks and help retain beneficiaries’ trust on nutrition supplementation initiatives.
Nonlinear Optical Properties of Two Different Nanoassemblies of Polydiacetylene (PDA): PDA Nanovesicles and PDA Nanocrystals  [PDF]
B. Bhushan, T. Kundu, B. P. Singh
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.34042
Abstract:

We have synthesized and characterized two different nanoassemblies of polydiacetylene (PDA), PDA nanovesicles and PDA nanocrystals, in order to study the influence of chain packing geometry of the two nanoassemblies on their third order nonlinear optical properties. The second molecular hyperpolarizability γ(-ω,ω,-ω,ω)of the two samples was investigated by antiresonant ring interferometric nonlinear spectroscopic (ARINS) technique using femtosecond modelocked Ti:sapphire laser in the spectral range of 720 nm - 820 nm. The observed spectral dispersion of γ has been explained in the framework of three-essential states model involving the ground state, a one-photon excited state and a two-photon excited state. The observed optical nonlinearity has been correlated with the electronic structure of the two samples. The energy of two-photon state, transition dipole moments and line width of the transitions have been estimated. Our studies show that the arrangement of polymer chains in polydiacetylene nanocrystals is more favorable for higher nonlinearity.

Bending a slab of neural tissue
Partha P. Mitra
Physics , 2005,
Abstract: In comparative and developmental neuroanatomy one encounters questions regarding the deformation of neural tissue under stress. The motivation of this note is an observation (Barbas {\it et al}) that at cortical folds or gyri, the layers of neural tissue show relative thickening or thinning of upper or deep layers. In general, the material properties of a slab of neural tissue are not known, and even if known, would probably lead to a difficult problem in elasticity theory. Here a simple argument is presented to show that bending an elastic slab should produce a relative thickening of the layers on the inside of the bend. The argument is based on the incompressibility of the material and should therefore be fairly robust.
Universal R-Matrix of Reductive Lie Algebras
A. Kundu,P. Truini
Physics , 1994,
Abstract: The aim of the paper is to build a universal R-matrix for the multiparameter deformation of any reductive Lie algebra. Such deformations, formulated in the recent past by Truini and Varadarajan, have the property of universality in a certain class and are shown by the present paper to be quasitriangular Hopf algebras. In order to build the R-matrix we exploit the twisting method for introducing new parameters as well as for making the transition to the reductive case. The physical motivation behind this construction is in the theory of integrable models: we intend to use such R-matrix for building the associated quantum R-matrix and Lax operators with spectral as well as color parameters - the color parameters being provided by the eigenvalues of the central generators of the reductive Lie algebra in a given representation. In this letter we present only the explicit form of the universal R-matrix of reductive Lie algebras and postpone its application to a forthcoming paper.
A Technique for Characterizing the Development of Rhythms in Bird Song
Sigal Saar, Partha P. Mitra
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001461
Abstract: The developmental trajectory of nervous system dynamics shows hierarchical structure on time scales spanning ten orders of magnitude from milliseconds to years. Analyzing and characterizing this structure poses significant signal processing challenges. In the context of birdsong development, we have previously proposed that an effective way to do this is to use the dynamic spectrum or spectrogram, a classical signal processing tool, computed at multiple time scales in a nested fashion. Temporal structure on the millisecond timescale is normally captured using a short time Fourier analysis, and structure on the second timescale using song spectrograms. Here we use the dynamic spectrum on time series of song features to study the development of rhythm in juvenile zebra finch. The method is able to detect rhythmic structure in juvenile song in contrast to previous characterizations of such song as unstructured. We show that the method can be used to examine song development, the accuracy with which rhythm is imitated, and the variability of rhythms across different renditions of a song. We hope that this technique will provide a standard, automated method for measuring and characterizing song rhythm.
Leaching behaviour of pendimethalin causes toxicity towards different cultivars of Brassica juncea and Brassica campestris in sandy loam soil
Subhendu Bandyopadhyay, Partha P. Choudhury
Interdisciplinary Toxicology , 2009, DOI: 10.2478/v10102-009-0025-z
Abstract: An experiment was conducted at the farm of Zonal Adaptive Research Station, Uttar Banga Krishi Viswavidhyalaya, Pundibari, Cooch Behar, West Bengal to evaluate the effect of pendimethalin on the yield, weed density and phytotoxicity in different varieties of rai (Brassica juncea) and yellow sarson (B. campestris var. yellow sarson) under higher soil moisture regime in Terai region of West Bengal. Pre-emergence application of pendimethalin at higher dose i.e. 1.0 kg/ha recorded higher plant mortality (30.92%) due to the presence of higher concentration of pendimethalin residue (0.292 μg/g) till the tenth day of crop age and consequently had the reduced yield (12.59 q/ha) than the dose of 0.7 kg/ha (13.33 q/ha) where plant mortality was only 12.62% due to comparatively lower level of pendimethalin residue (0.192 μg/g). Although the application of pendimethalin at the rate of 1.0 kg/ha was able to control weed more efficiently (18.96/m2) than the dose of 0.7 kg/ha (30.41/m2) and subsequent lower doses. The herbicide leached down to the root zone resulting in phytotoxicity towards crop. Yellow sarson group (Brassica campestris) showed more susceptibility than rai (Brassica juncea) group against pendimethalin application at higher doses.
A General Class of Collatz Sequence and Ruin Problem
Nabarun Mondal,Partha P. Ghosh
Physics , 2012,
Abstract: In this paper we show the probabilistic convergence of the original Collatz (3n + 1) (or Hotpo) sequence to unity. A generalized form of the Collatz sequence (GCS) is proposed subsequently. Unlike Hotpo, an instance of a GCS can converge to integers other than unity. A GCS can be generated using the concept of an abstract machine performing arithmetic operations on different numerical bases. Original Collatz sequence is then proved to be a special case of GCS on base 2. The stopping time of GCS sequences is shown to possess remarkable statistical behavior. We conjecture that the Collatz convergence elicits existence of attractor points in digital chaos generated by arithmetic operations on numbers. We also model Collatz convergence as a classical ruin problem on the digits of a number in a base in which the abstract machine is computing and establish its statistical behavior. Finally an average bound on the stopping time of the sequence is established that grows linearly with the number of digits.
Algorithmic choice of coordinates for injections into the brain: encoding a neuroanatomical atlas on a grid
Pascal Grange,Partha P. Mitra
Physics , 2011,
Abstract: Given an atlas of the brain and a number of injections to be performed in order to map out the connections between parts of the brain, we propose an algorithm to compute the coordinates of the injections. The algorithm is designed to sample the brain in the most homogeneous way compatible with the separation of brain regions. It can be applied to other species for which a neuroanatomical atlas is available. The computation is tested on the annotation at a resolution of 25 microns corresponding to the Allen Reference Atlas, which is hierarchical and consists of 209 regions. The resulting injection coordinates are being used for the injection protocol of the Mouse Brain Architecture project. Due to its large size and layered structure, the cerebral cortex is treated in a separate algorithm, which is more adapted to its geometry.
Universal Computation Is 'Almost Surely' Chaotic
Nabarun Mondal,Partha P. Ghosh
Computer Science , 2011,
Abstract: Fixed point iterations are known to generate chaos, for some values in their parameter range. It is an established fact that Turing Machines are fixed point iterations. However, as these Machines operate in integer space, the standard notions of a chaotic system is not readily applicable for them. Changing the state space of Turing Machines from integer to rational space, the condition for chaotic dynamics can be suitably established, as presented in the current paper. Further it is deduced that, given random input, computation performed by a Universal Turing Machine would be 'almost surely' chaotic.
第1页/共201318条
每页显示


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