Explicit Space-Time Codes Achieving The Diversity-Multiplexing Gain Tradeoff

A recent result of Zheng and Tse states that over a quasi-static channel, there exists a fundamental tradeoff, referred to as the diversity-multiplexing gain (D-MG) tradeoff, between the spatial multiplexing gain and the diversity gain that can be simultaneously achieved by a space-time (ST) block code. This tradeoff is precisely known in the case of i.i.d. Rayleigh-fading, for T>= n_t+n_r-1 where T is the number of time slots over which coding takes place and n_t,n_r are the number of transmit and receive antennas respectively. For T < n_t+n_r-1, only upper and lower bounds on the D-MG tradeoff are available. In this paper, we present a complete solution to the problem of explicitly constructing D-MG optimal ST codes, i.e., codes that achieve the D-MG tradeoff for any number of receive antennas. We do this by showing that for the square minimum-delay case when T=n_t=n, cyclic-division-algebra (CDA) based ST codes having the non-vanishing determinant property are D-MG optimal. While constructions of such codes were previously known for restricted values of n, we provide here a construction for such codes that is valid for all n. For the rectangular, T > n_t case, we present two general techniques for building D-MG-optimal rectangular ST codes from their square counterparts. A byproduct of our results establishes that the D-MG tradeoff for all T>= n_t is the same as that previously known to hold for T >= n_t + n_r -1.Comment: Revised submission to IEEE Transactions on Information Theor

Response of the Arabian Sea to global warming and associated regional climate shift

The response of the Arabian Sea to global warming is the disruption in the natural decadal cycle in the sea surface temperature (SST) after 1995, followed by a secular warming. The Arabian Sea is experiencing a regional climate-shift after 1995, which is accompanied by a five fold increase in the occurrence of “most intense cyclones”. Signatures of this climate-shift are also perceptible over the adjacent landmass of India as: (1) progressively warmer winters, and (2) decreased decadal monsoon rainfall. The warmer winters are associated with a 16-fold decrease in the decadal wheat production after 1995, while the decreased decadal rainfall was accompanied by a decline of vegetation cover and increased occurrence of heat spells. We propose that in addition to the oceanic thermal inertia, the upwelling-driven cooling provided a mechanism that offset the CO2-driven SST increase in the Arabian Sea until 1995

What drives the increased phytoplankton biomass in the Arabian Sea?

The seasonal variability of phytoplankton biomass in the Arabian Sea, though a well researched topic, its inter-annual variability is less explored and understood. Analysis of the satellite-derived chlorophyll pigment concentration in the Arabian Sea during 1997–2007 showed a weak increasing trend. Contrary to the earlier hypothesis, our analysis showed that this increased phytoplankton biomass was not driven by the strengthening winds during summer monsoon. In fact, the basin-averaged chlorophyll concentrations during summer monsoon tend to decline, whereas those in September–October and during the winter monsoon showed an increasing trend. Based on the analysis of wind and aerosol optical thickness data, we attribute the increased phytoplankton biomass during September–October to dust-induced iron fertilization when there is sufficient buildup of nitrate in the upper ocean. During winter, the enhanced evaporative cooling under the strengthening winds led to the increased convective mixing. Subsequent supply of subsurface nutrients to the euphotic zone coupled with the increased dust delivery support the observed increase in phytoplankton biomass during winter

Evaluation of the effect of magnesium in combination with organic manures on the growth and yield attributes and yield of cotton (Gossypium hirsutum L.) inTypic Ustropept

Cotton is India's most significant commercial crop and has a significant role in the agricultural economics of the nation. A field experiment was conducted in a farmer’s field located in Achchandavilthan village of Srivillipudhur block, Virudhunager District, from 28-Aug 2019 to Jan, 2020 to evaluate the response of cotton to foliar and soil application of magnesium combination with organic manures on the growth and yield attributes and yield of cotton in magnesium deficient soil. The soil was categorized as “Moderately deep clay Typic Ustropept, and medium N, P and high K content, in a randomized block design with fifteen treatments and three replications. The results revealed that the application of MgSO4 at a rate of 50 kg ha-1 along with 250 kg vermicompost for 30 days (1:5 ratio) at critical stages of crop growth along with the Soil Test Crop Response (STCR) based N,P2O5 and K2O RDF registered the maximum plant height at all three stages (40,70 and harvest) of crop growth (94.7, 122.3 and 222.2 cm), number of monopodial branches plant-1 (33.4), number of sympodial branches plant-1(73.1), numbers of boll plant-1 (48.3), boll weight (3.9 g), and seed cotton yield (26.2 q ha-1). This was followed by treatment (T9) MgSO4 at a rate of 50 kg ha-1 incubated with 500 kg FYM for 30 days (1:10 ratio) along with STCR) based N,P2O5 and K2O RDF and the lowest treatment receiving the recommended dose of N, P2O5 and K2O alone (80:40:40 kg ha1). It was revealed that natural chelated fertilizer prepared from MgSO4 incubated with organic manures for 30 days significantly improved the growth and yield of cotton

Effects of Molecular Crowding on stretching of polymers in poor solvent

We consider a linear polymer chain in a disordered environment modeled by percolation clusters on a square lattice. The disordered environment is meant to roughly represent molecular crowding as seen in cells. The model may be viewed as the simplest representation of biopolymers in a cell. We show the existence of intermediate states during stretching arising as a consequence of molecular crowding. In the constant distance ensemble the force-extension curves exhibit oscillations. We observe the emergence of two or more peaks in the probability distribution curves signaling the coexistence of different states and indicating that the transition is discontinuous unlike what is observed in the absence of molecular crowding.Comment: 14 pages, 6 figure

OBJECT ORIENTED CLASSIFICATION AND FEATURE EXTRACTION FOR PARTS OF EAST DELHI USING HYBRID APPROACH

Rapid urbanization of Indian cities requires a focused attention with respect to preparation of Master Plans of cities. Urban land use/land cover from very high resolution satellite data sets is an important input for the preparation of the master plans of the cities along with extraction of transportation network, infrastructure details etc. Conventional classifiers, which are pixel based do not yield reasonably accurate urban land use/land cover classification of very high resolution satellite data (usually merged images of Panchromatic &amp; Multispectral). Object Based Image Classification techniques are being used to generate urban land use maps with ease which is GIS compatible while using very high resolution satellite data sets. In this study, Object Based Image Analysis (OBIA) has been used to create broad level urban Land Use / Land Cover (LU/LC) map using high resolution ResourceSat-2 LISS-4 and Cartosat-1 pan-sharpened image on the study area covering parts of East Delhi City. Spectral indices, geometric parameters and statistical textural methods were used to create algorithms and rule sets for feature classification. A LU/LC map of the study area comprising of 4 major LU/LC classes with its main focus on separation of barren areas from built up areas has been attempted. The overall accuracy of the result obtained is estimated to be approximately 70%

Rheological Behavior of Aqueous Suspensions of Laponite: New Insights into the Ageing Phenomena

In this paper, ageing behavior of suspensions of laponite with varying salt concentration is investigated using rheological tools. It is observed that the ageing is accompanied by an increase in the complex viscosity. The succeeding creep experiments performed at various ages showed damped oscillations in the strain. The characteristic time-scale of the damped oscillations, retardation time, showed a prominent decrease with the age of the system. However, this dependence weakens with an increase in the salt concentration, which is known to change microstructure of the system from glass-like to gel-like. We postulate that a decrease in the retardation time can be represented as a decrease in the viscosity (friction) of the dissipative environment surrounding the arrested entities that opposes elastic deformation of the system. We believe that ageing in colloidal glass leads to a greater ordering that enhances relative spacing between the constituents thereby reducing the frictional resistance. However, since a gel state is inherently different in structure (fractal network) than that of a glass (disordered), ageing in the same does not induce ordering. Consequently, we observe inverse dependence of retardation time on age becoming weaker with an increase in the salt concentration. We analyze these results from a perspective of ageing dynamics of both glass state and gel state of laponite suspensions.Comment: 27 Pages, 12 figure

Spear-fishing with surface supplied diving disturbs the ecological balance in Gulf of Mannar, southeast India

71-74Gulf of Mannar in southeast coast of India is considered an important biodiversity hotspot providing a variety of fishery resources. Spear-fishing, involving surface-supplied diving has become a significant threat in the Tuticorin region of Gulf of Mannar and was documented in August 2018. It is understood from the fishermen that spear-fishing is used as an opportunistic fishing method when the visibility is good. Using an iron rod of about 1.5 m, they catch commercially important fin- and shell-fishes including groupers, cat fishes, parrot fishes, rays, squids, trigger fishes, lobsters, crabs, etc. The practitioners of this harmful method target the ecologically important fishes such as parrot fishes, and this targeted collection adversely impacts the ecosystem by disturbing the ecological balance. This study makes a strong case for banning this activity before it spreads to other regions

APTAMER: A REVIEW ON IT’S IN VITRO SELECTION AND DRUG DELIVERY SYSTEM

In recent year, Aptamer has been one of the key tools in the field of advanced drug delivery systems. Aptamer are oligonucleotides or peptides that bind to a specific target molecule. In this review we summarize the major differences between the antibody and an Aptamer along with the different methodology of the In vitro selection of the Aptamer by using SELEX (Systematic evolution of ligands by exponential enrichment) technique. SELEX is a technique which has a based biosensor and some of the novel drug delivery system. The article referred in this review was referred from the above said source was in the range of 1990-2020 y. Primary contents is searched from science direct, springer nature, scopus indexed journals. The resources are downloaded from google scholar, peer-reviewed published literature from scientific journals and books

SOMES: A REVIEW ON COMPOSITION, FORMULATION METHODS AND EVALUATIONS OF DIFFERENT TYPES OF “SOMES” DRUG DELIVERY SYSTEM

Many drugs are available in the market for several diseases, disorder or even for a condition, but it is difficult to select a suitable carrier to attain maximum bioavailability and potential for a potent drug. Attaining a controlled and sustained release of a drug is purely focused on the selection of a carrier (natural, synthetic and hybrid) like nanosomes. Nanosomes have become a prominent tool in the field of pharmacy. Nanosomes are small uniform structures which deliver the drug to the specific targeted site, which mainly depends upon the presence of ligands, shape, size and surface chemistry. Nanosomes are available in various types which include Niosomes, Liposomes, Electrosomes, Aquasomes, Transfersomes, Phytosomes, Enzymosomes, Ethosomes, Invasome and Sphingosomes. In general, all these nanosomes are quite similar in nature with minute differences in their vesicular characteristics and composition. This review traces various ‘somes’ composition and their role in the formulation, applications, advantages, disadvantages, common formulation procedures and evaluation parameters