125,932 research outputs found
Security beyond survival essays for K. Subrahmanyam
No full textKrishna Swami Subrahmanyam, b. 1929, Indian scientist; contributed articles
Design of molecularly imprinted polymers for sensors and solid phase extraction
No full textThis thesis presents broadly the applications of molecularly imprinted polymers in
sensors and solid phase extraction. Sensors for creatine and creatinine have been
reported using a novel method of rational design of molecularly imprinted polymers
(MIPs), and solid phase extraction of aflatoxin-B 1 has also been described in the
thesis.
A method for the selective detection of creataine and creatinine is reported in this
thesis, which is based on the reaction between polymerised hemithioacetal, formed by
allyl mercaptan, o-phthalic aldehyde, and primary amine leading to the formation of
fluorescent isoindole complex. This method was demonstrated for the detection of
creatine using creatine-imprinted MIPs. Since MIPs created using traditional methods
were unable to differentiate between creatine and creatinine, a new approach to the
rational design of a MIP selective for creatinine was developed using computer
simulation. A virtual library of functional monomers was assigned and screened
against the target molecule, creatinine, using molecular modeling software. The
monomers giving the highest binding score were further tested using simulated
annealing in order to mimic the complexation of the functional monomers with
template in the monomer mixture. The result of this simulation gave an optimised
MIP composition. The computationally designed polymer demonstrated superior
selectivity in comparison to the polymer prepared using traditional approach, a
detection limit of 25 μM and good stability. The 'Bite-and- Switch' approach
combined with molecular imprinting can be used for the design of assays and sensors,
selective for amino containing substances.
MEP for the selective binding properties for aflatoxin-B 1 was prepared using the
computational approach. The results obtained demonstrate that the MISPE offers a
simple, convenient and a rapid methodology for solid phase extraction of aflatoxin-B 1
even at very low concentrations of 2 ppb. The commercially available C-18 cartridges
were able to recover only about 52% of aflatoxin-B 1 at concentrations of 2 ppb when
compared with almost complete recovery by the MIP. We have proved here that,
MIPs as a solid phase extraction materials offer important and practical advantages
with respect to other solid phase extraction methodologies
Sea surface height variability in the Indian Ocean from TOPEX/POSEIDON altimetry and model simulations
No full textSea Surface Height (SSH) variability in the Indian Ocean during 1993-1995 is studied using TOPEX/POSEIDON (T/P) altimetry data. Strong interannual variability is seen in the surface circulation of the western Arabian Sea, especially in the Somali eddy structure. During the Southwest (SW) monsoon, a weak monsoon year is characterized by a single eddy system off Somalia, a strong or normal monsoon year by several energetic eddies. The Laccadive High (LH) and Laccadive Low (LL) systems off southwest India are observed in the altimetric SSH record. The variability of the East India Coastal Current (EICC), the western boundary current in the Bay of Bengal, is also detected. Evidence is found for the propagation of Kelvin and Rossby waves across the northern Indian Ocean; these are examined in the context of energy transfer to the western boundary currents, and associated eddies. A simple wind-driven isopycnal model having three active layers is implemented to simulate the seasonal changes of surface and subsurface circulation in the North Indian Ocean and to examine the response to different wind forcing. The wind forcing is derived from the ERS-1 scatterometer wind stress for the same period as the T/P altimeter data, enabling the model response in different (active/weak) monsoon conditions to be tested. The model output is derived in 10-day snapshots to match the time period of the T/P altimeter cycles. Complex Principal Component Analysis (CPCA) is applied to both altimetric and model SSH data. This confirms that long Rossby waves are excited by the remotely forced Kelvin waves off the southwest coast of India and contribute substantially to the variability of the seasonal circulation in the Arabian Sea
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Indian Ocean Rossby waves observed in TOPEX/POSEIDON altimeter data and in model simulations
No full textConstructive Non-Commutative Rank Computation Is in Deterministic Polynomial Time
No full textLet {\mathcal B} be a linear space of matrices over a field {\mathbb spanned by n\times n
matrices B_1, \dots, B_m. The non-commutative rank of {\mathcal B}$ is the minimum r\in {\mathbb N} such that there exists U\leq {\mathbb F}^n satisfying \dim(U)-\dim( {\mathcal B} (U))\geq
n-r, where {\mathcal B}(U):={\mathrm span}(\cup_{i\in[m]} B_i(U)).
Computing the non-commutative rank generalizes some well-known problems including the bipartite graph maximum
matching problem and the linear matroid intersection problem.
In this paper we give a deterministic polynomial-time algorithm to compute the
non-commutative rank over
any field {\mathbb F}. Prior to our work, such
an
algorithm was only known over the rational number field {\mathbb Q}, a result due to Garg et al, [GGOW]. Our algorithm is constructive and produces a witness
certifying the non-commutative rank, a feature that is missing in the algorithm from [GGOW].
Our result is built on techniques which we developed in a previous paper [IQS1], with a new reduction procedure that
helps to keep the blow-up parameter small. There are two ways to realize this
reduction. The first involves constructivizing a key result
of Derksen and Makam [DM2] which they developed in order to prove that the null cone
of matrix semi-invariants is cut out by generators whose degree is polynomial in the size of the matrices involved. We also give a second, simpler method to achieve this. This
gives another proof of the polynomial upper bound on the degree of the generators cutting out the null cone of matrix
semi-invariants.
Both the invariant-theoretic result and the algorithmic result rely crucially
on the regularity lemma proved in [IQS1]. In
this paper we improve on the constructive version of the regularity lemma from [IQS1] by removing a technical coprime
condition that was assumed there
Pragmatic Case Studies as a Source of Unity in Applied Psychology
No full textTo unify or not to unify applied psychology: that is the question. In this article we review pendulum swings in the historical efforts to answer this question—from a comprehensive, positivist, “top-down,” deductive yes between the 1930s and the early 60s, to a postmodern no since then. A rationale and proposal for a limited, “bottom-up,” inductive yes in applied psychology is then presented, employing a case-based paradigm that integrates both positivist and postmodern themes and components. This paradigm is labeled “pragmatic psychology” and, its specific use of case studies, the “Pragmatic Case Study Method” (“PCS Method”). We call for the creation of peer-reviewed journal-databases of pragmatic case studies as a foundational source of unifying applied knowledge in our discipline. As one example, the potential of the PCS Method for unifying different angles of theoretical regard is illustrated in an area of applied psychology, psychotherapy, via the case of Mrs. B. The article then turns to the broader historical and epistemological arguments for the unifying nature of the PCS Method in both applied and basic psychology.Peer reviewe
A promising plasma-catalytic approach towards single-step methane conversion to oxygenates at room temperature
No full textDirect conversion of methane into chemicals and fuels under mild conditions has been considered as a ‘holy grail’ of chemistry and catalysis in the 21st century. Plasma-catalytic partial oxidation of methane (POM) to higher-value liquid fuels and chemicals over supported transition metal catalysts (Ni/γ-Al2O3, Cu/γ-Al2O3 and Fe/γ-Al2O3) has been investigated in a co-axial dielectric barrier discharge (DBD) reactor at room temperature and atmospheric pressure. The selectivity of oxygenates was 58.3% in the plasma POM reaction without a catalyst, while the combination of DBD with the catalysts enhanced the selectivity of oxygenates up to 71.5%. Of the three catalysts, Fe/γ-Al2O3 showed the highest methanol selectivity of 36.0% and a significant methanol yield of 4.7%, while the use of Cu/γ-Al2O3 improved the selectivity of C2 oxygenates to 9.4%, which can be attributed to the presence of more acid sites on the surfaces of the Cu catalyst. The possible reaction pathways in the plasma-catalytic POM reaction have been explored by combined means of plasma electrical and optical diagnostics, analysis of gas and liquid products, as well as comprehensive catalyst characterization. The plausible reaction routes for the production of major oxygenate (methanol) on the Fe/γ-Al2O3 surfaces have been proposed. The surface CHx species are found to be critical for methanol synthesis; they can be formed through the direct adsorption of CHx radicals generated in the plasma gas-phase reactions or through the dissociation of adsorbed CH4 on the catalyst surface
Dr. Edwin Wright Collection: Author Unknown
No full textNotes - The author relates several short stories about his neighbours including Alex McDonell, homesteading and life around Meanook and Athabasca (1 page
- …
