Search

A personal narrative is presented which explores the authors' experience of meeting Dr. Sudhanshu Kumar Jain.

The article discusses the improving trends and the emerging challenges in plant taxonomy in India. It states the introduction of the alternative term biosystematics and the establishment of species concept. It mentions the disparity between classical taxonomists and biosystematics due to the introduction of experimental taxonomy.

The article examines the role of ethnobotany in seeking new medicinal plants in India as of January 2016 and on the role of tribal wisdom in biological diversity conservation. It offers information on ethnobotany which is a synthetic discipline that involves allied subjects including botany, mythology, and archaeology. Also discussed are the methods of gathering ethno-botanical information, analysis of herbarium, and ancient literature on ethnobotany.

During winter, along the east coast of India, the near-surface flow is characterized by the southward-flowing East India Coastal Current (EICC) which bends around Sri Lanka and enters into the south-eastern Arabian Sea (AS). This current carries cooler, low-salinity waters from the head Bay of Bengal (BoB) into the south-eastern AS. But due to a lack of any direct in situ measurements, it is not clear whether any part of this current that flows through the Indo-Sri Lanka Channel (ISLC) is significant. An attempt is made in this study to look for any observational evidence for the southward flow of cooler, low salinity waters through the ISLC during winter. In the absence of direct in situ measurements on the observed currents in the non-navigable shallow ISLC, the observed high resolution, advanced very high resolution radiometer (AVHRR) sea surface temperature (SST), and sea-viewing wide field-of-view sensor (SeaWiFS) chlorophyll-a and historic sea surface salinity (SSS) data are utilized as tracers to track any southward water flow through the Pamban Pass and Adam's Bridge in the ISLC. The analysis suggests that both the non-navigable shallow Pamban Pass and the Adam's Bridge in the ISLC act as barriers and limit the southward flow of cooler, low salinity waters into the Gulf of Mannar in the south during winter. [ABSTRACT FROM AUTHOR]

Shompens, a dwindling and critically endangered Mongoloid aboriginal tribe inhabiting the Great Nicobar Island, indicate poor prospects of population growth in the near future. Ethnobotanical studies conducted among the Shompens inhabiting Jhaunala, Laful, Shompenhut and Kopenheat areas have revealed some interesting plants used for food, medicine, hut construction, canoe making and honey collection. Botanical name, family, Shompen name and plant parts used are recorded along with their unique usage. [ABSTRACT FROM AUTHOR]

Lanthanum hexa-aluminate (LHA) is considered a promising material for thermal barrier coatings for gas turbine applications as well as oxidation resistant coatings for fibres in oxide based ceramic composites. Combustion synthesis has attractive advantages such as simple experimental setup, low cost, short reaction time, energy savings due to exothermic reaction, better control of stoichiometry and fine powder size. The present study involves combustion synthesis of LHA using lanthanum and aluminium nitrates as oxidising precursors, and urea as fuel. The precursor salts were dissolved in a minimum amount of deionised water and the solution was heated in a mantle heater to temperatures of around 300–350°C, at which combustion takes place with rapid evolution of gas. The LHA powder was also prepared by a precipitation route for comparative study. The as synthesised powders were calcined at up to 1450°C and subjected to X-ray diffraction for phase evolution studies. Product powders were then characterised. The influence of the lanthanum/aluminium molar ratio in the starting composition and the effect of temperature on the formation sequences of lanthanum monoaluminate (LMA) and LHA and on the conversion of LMA to LHA are discussed. [ABSTRACT FROM AUTHOR]

The article discusses the emergence of a new weed called Ambrosia psilostachya which poses a potential threat to the Indian flora. It notes that the species has formed a new record as the second species of the genus Ambrosia in India. It hopes that all botanists, agronomists, weed scientists, agriculture administrators and local non-governmental organizations will seriously address the threat of the weed species to the farming sector.

The article discusses the occurrence of Phyllanthus scabrifolius in Amingad, Bagalkot district, Karnataka, India. The habitat of the species is described. Results of the critical examination and study of the specimens revealed to what species they belong. The Botanical Survey of India provided confirmation on the identity of the specimens.

The exergy-enthalpy and temperature-exergy diagrams have been generated in the range 0.1-10 MPa and from the triple point to 500 K. Thesediagrams on the International Temperature Scale (ITS-90) have been generated using a calculation scheme proposed by Jacobsen et al. A computer program is developed for calculating the thermodynamic properties of nitrogen, including exergy as a property, from the triple pointto 800 K at pressures up to 30 MPa. These exergy based thermodynamicproperty charts can be useful in the energy efficiency analyses of cryorefrigeration cycles involving nitrogen as a working medium. A sample analysis is included. [ABSTRACT FROM AUTHOR]

Turfgrass quality is generally determined by researchers based on their previous experience. This evaluation mechanism has been used to gather performance data on a large collection of turfgrass cultivars in National Turfgrass Evaluation Program (NTEP) studies across the United States. NTEP collects data, evaluates it, and distributes the findings to turfgrass managers and educators. We developed an automated procedure for exploring the NTEP database to discover instances of high cultivar quality or performance in unique growing conditions. In previous work, a procedure was developed to pre-process the data to normalize differences among evaluators and the C4 learning algorithm was selected as the most useful for automatically learning rules that identified the unique growing conditions for high quality cultivars. This study examined only a small portion of the NTEP database. C4 discovered 85 rules by examining data collected for 20 Kentucky bluegrass(Poa pratensis L.) cultivars over an eight-year period. Of these 85 rules, 71% fit the accepted management and environmental parameters for Kentucky bluegrass. The remaining 29% of the rules showed unexpected relationships among management and environmental parameters. A best-management expert system for turf would require a more comprehensive examination of the NTEP database along with many additional rules covering turf management operations. [ABSTRACT FROM AUTHOR]

In this paper, a synthesized design of the magnetron injection gun (MIG) for a 200 kW, 42 GHz gyrotron is presented. The synthesis steps involve the selection of the type of the MIG, the development of the design criteria, the selection of initial design parameters and the development of a program for the estimation of the synthesized parameters for the MIG design. The presented approach estimates the cathode, the beam and the anode parameters, enabling one to build a synthesis model of a complete MIG system. [ABSTRACT FROM AUTHOR]

The formation mechanisms of the barrier layer (BL) and its seasonal variability in the Arabian Sea (AS) are studied using a comprehensive dataset of temperature and salinity profiles from Argo and other archives for the AS. Relatively thick BL of 20–60 m with large spatial extent is found in the central-southwestern AS (CSWAS), the convergence zone of the monsoon wind, during the peak summer monsoon (July–August) and in the southeastern AS (SEAS) and northeastern AS (NEAS) during the winter (January–February). Although the BL in the SEAS has been reported before, the observed thick BL in the central-southwestern AS during the peak summer monsoon and in the northeastern AS during late winter are the new findings of this study. The seasonal variability of BL thickness (BLT) is closely related to the processes that occur during summer and winter monsoons. During both seasons, the Ekman processes and the distribution of low-salinity waters in the surface layer show a dominant influence on the observed BLT distributions. In addition, Kelvin and Rossby waves also modulate the observed BL thickness in the AS. The relatively low salinity surface water overlying the Arabian Sea high-salinity water (ASHSW) provides an ideal ground for strong haline stratification in the CSWAS (during summer monsoon) and in NEAS (during winter monsoon). During summer, northward advection of equatorial low-salinity water by the Somali Current and the offshore advection of low-salinity water from the upwelling region facilitate the salinity stratification that is necessary to develop the observed BL in the CSWAS. In the SEAS, during winter, the winter monsoon current (WMC) carries less saline water over relatively high salinity ambient water to form the observed BL there. The winter West India Coastal Current (WICC) transports the low-salinity water from the SEAS to the NEAS, where it lies over the subducted ASHSW leading to strong haline stratification. Ekman pumping together with the downwelling Kelvin wave in the NEAS deepen the thermocline to cause the observed thick BL in the NEAS. [ABSTRACT FROM AUTHOR]

Floral phenology, pollination biology and breeding system were studied in Aristolochia tagala Cham. (Aristolochiaceae) grown under ex situ conditions. The flower exhibits structural features typical of fly-trap mechanism described for other Aristolochia species. Flowers show pronounced protogyny. Stigmas are receptive at anthesis and remain so for 24 h. Anthers dehisce 45-48 h after anthesis by which time stigma receptivity is lost. Chironomid fly (Diptera) is the pollinator. Attracted by the odour and colour of the flower, the flies enter it and are detained in the chamber of the perianth tube (where the anthers and stigma are located) for nearly 50 h. Their escape is prevented by the presence of dense downward-pointing hairs in the perianth tube. The nectaries provide food to the insects. Following anther dehiscence, the thorax of the flies becomes loaded with sticky pollen grains. Hairs on the inner wall of the perianth tube wither and facilitate the exit of the flies. When a fly carrying the pollen load enters a fresh flower, it brings about pollination. Manual pollinations showed that the species permits geitonogamous pollination. The percentage of fruit set in manually pollinated flowers is higher than that resulting from open pollination, confirming that pollination is a limitation for fruit set in the ex situ-grown population. Nevertheless, fruit and seed set is sufficiently high for ex situ conservation purposes. [ABSTRACT FROM AUTHOR]

The pulsed excimer laser ablation method is used to deposit both the buffer layer of Y-stabilized ZrO2 and the overlayer of Y1Ba2Cu3O7-x superconductor on (100) oriented single-crystal silicon. Process parameter optimization study is carried out and it is shown that a thin film of the superconductor (0.5–0.7 μm) having a zero resistance temperature of 86 K can be obtained using a 0.3 μm buffer layer deposited at substrate temperatures between 600 and 800 °C. [ABSTRACT FROM AUTHOR]

We studied the magnetic ordering of thin films and bulk crystals of rutile RuO2 using resonant x-ray scattering across the Ru L2 absorption edge. Combining polarization analysis and azimuthal angle dependence of the magnetic Bragg signal, we have established the presence and characteristic of collinear antiferromagnetism in RuO2 with TN>300 K. In addition to revealing a spin-ordered ground state in the simplest ruthenium oxide compound, the persistence of magnetic order even in nanometer-thick films lays the ground for potential applications of RuO2 in antiferromagnetic spintronics. [ABSTRACT FROM AUTHOR]

Underwater gliders measure high-resolution spatiotemporal oceanographic data. In April 2014, the National Institute of Ocean Technology, Chennai operated an underwater glider 'Barathi', for 127 days for observation of Bay of Bengal (BoB). In this article we present the effectiveness of the glider Barathi for high resolution temporal sampling of the surface layer in the central BoB for studying variation of temperature, salinity and density structures and acoustic characteristics on 26-27 May 2014. The results showed 'afternoon effect' on acoustic characteristics and formation of secondary sound channel. Our data set is strongly correlated (coefficient of determination r2 > 0.96) with data from a nearby Array for real-time geostrophic Oceanography (Argo) float. [ABSTRACT FROM AUTHOR]

The article discusses the application of indigenous Lagrangian drifter in detecting sea-surface temperature (SST) anomaly in the equatorial region of Bay of Bengal. It notes that SST is one of the critical parameters related to the global ocean-atmosphere system playing a key role in studies of air-sea heat exchange, upper ocean processes, and weather forecast. An overview of the Pradyu drifter is provided.

Ambient noise recorded at shallow southwestern Bay of Bengal during September 2010 has been analyzed for spectral characteristics in the band 0.1-5.0 kHz. The noise level (NL) exhibits diurnal periodicity in the band 0.5-2.0 kHz, during most of the day. The in situ wind data at the site correlates well with the NL, which also shows a diurnal cycle. Wavelet analysis further carried out establishes of the diurnal periodicity in wind/NL pattern during fair weather conditions under the influence of local wind effects. Wavelet coherence shows wind and noise to be in phase or wind leading noise. Diurnal variation in wind is more frequently observed along the coast in tropical regions due to differential heating of land and sea, and this has attributed to the NL pattern at the site. The period of measurement is also favorable for the formation of such localized circulation since it is the sunny unclouded period prior to the Bay of Bengal cyclone season and the northeast monsoon. [ABSTRACT FROM AUTHOR]

Drifter buoys are globally deployed to measure surface meteorological and oceanographic variables. A Lagrangian drifting buoy (Pradyu II) to measure sea-surface temperature and current has been developed at the National Institute of Ocean Technology, Chennai. The drifter buoy with geostationary satellite communication (INSAT-3C) to have near real-time data at every hour is a unique attempt in the history of drifting buoy nodes. This article describes Pradyu II drifting buoy node, design of low-power embedded system, communication network and field test results from an experiment conducted in the Bay of Bengal during March-April 2013. The results from Pradyu II are compared with commercially available drifting buoy (Marlin-Yug), moored data buoy (BD11) and remotely sensed data. [ABSTRACT FROM AUTHOR]

The Bay of Bengal, the northeastern limb of the tropical Indian Ocean is a region strongly coupled with summer and winter monsoons and tropical cyclones. The Bay is also a region of strong vertical stratification near the surface due to large inputs of freshwater through rainfall and river run-off. In situ subsurface ocean measurements are quite sparse both in space and time in this region. The National Institute of Ocean Technology (NIOT), Chennai deployed instrumented moored buoys in the Bay since 1997 to provide continuous time-series measurements of surface meteorological and oceanographic parameters at selected locations. In the recent years several studies have shown the important role of variability of heat storage in the near-surface layers on the intraseasonal and interannual evolution of monsoons and cyclones. Hence a strong need was felt to augment some of these buoys with subsurface temperature, salinity and current sensors to continuously record the temporal evolution of their vertical structures. Under a new initiative, NIOT has deployed six moored buoys attached with sensors to collect subsurface oceanographic parameters on real-time basis in the Bay. These are coded as the OMNI (Ocean Moored buoy Network for Northern Indian Ocean) buoy system. The time-series of vertical profiles of temperature and salinity in 500 m water column from the surface and currents in the topmost 100 m water column are monitored at discrete depths in the Bay. The OMNI buoy programme addresses a long-standing need to understand the observed variability of upper ocean thermohaline and current structures on several timescales that has important bearing on the evolution of seasonal monsoons and cyclones. This article presents an account on the evolution, status and usefulness of the OMNI buoy programme. [ABSTRACT FROM AUTHOR]

Human pluripotent stem cell-derived neural progenitor (hNP) cells are an excellent resource for understanding early neural development and neurodegenerative disorders. Given that many neurodegenerative disorders can be correlated with defects in the mitochondrial genome, optimal utilization of hNP cells requires an ability to manipulate and monitor changes in the mitochondria. Here, we describe a novel approach that uses recombinant human mitochondrial transcription factor A (rhTFAM) protein to transfect and express a pathogenic mitochondrial genome (mtDNA) carrying the G11778A mutation associated with Leber's hereditary optic neuropathy (LHON) disease, into dideoxycytidine (ddC)-treated hNPs. Treatment with ddC reduced endogenous mtDNA and gene expression, without loss of hNP phenotypic markers. Entry of G11778A mtDNA complexed with the rhTFAM was observed in mitochondria of ddC-hNPs. Expression of the pathogenic RNA was confirmed by restriction enzyme analysis of the SfaN1-digested cDNA. On the basis of the expression of neuron-specific class III beta-tubulin, neuronal differentiation occurred. Our results show for the first time that pathogenic mtDNA can be introduced and expressed into hNPs without loss of phenotype or neuronal differentiation potential. This mitochondrial gene replacement technology allows for creation of in vitro stem cell-based models useful for understanding neuronal development and treatment of neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

BACKGROUND: Signaling mechanisms involved in early human germ cell development are largely unknown and believed to be similar to mouse germ cell development; however, there may be species specific differences. KIT ligand (KITL) and Bone morphogenetic protein 4 (BMP4) are necessary in mouse germ cell development and may play an important role in human germ cell development. [ABSTRACT FROM PUBLISHER]

Repeat XBT transects made at near-fortnightly intervals in the Lakshadweep Sea (southeastern Arabian Sea) and ocean data assimilation products are examined to describe the year-to-year variability in the observed near-surface thermal inversions during the winter seasons of 2002–06. Despite the existence of a large low-salinity water intrusion into the Lakshadweep Sea, there was an unusually lower number of near-surface thermal inversions during the winter 2005/06 compared to the other winters. The possible causative mechanisms are examined. During the summer monsoon of 2005 and the following winter season, unusually heavy rainfall occurred over the southwestern Bay of Bengal and the Lakshadweep Sea compared to other years in the study. Furthermore, during the winter of 2005, both the East India Coastal Current and the Winter Monsoon Current were stronger compared to the other years, transporting larger quantities of low salinity waters from the Bay of Bengal into the Lakshadweep Sea where a relatively cooler near-surface thermal regime persisted owing to prolonged upwelling until November 2005. In addition, the observed local surface wind field was relatively stronger, and the net surface heat gain to the ocean was weaker over the Lakshadweep Sea during the postmonsoon season of 2005. Thus, in winter 2005/06, the combination of prolonged upwelling and stronger surface wind field resulting in anomalous net surface heat loss caused weaker secondary warming of the near-surface waters in the Lakshadweep Sea. This led to a weaker horizontal sea surface temperature (SST) gradient between the Lakshadweep Sea and the intruding Bay of Bengal waters and, hence, a reduced number of thermal inversions compared to other winters despite the presence of stronger vertical haline stratification. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the composition of the oil extracted from Limonia acidissima. The study collected leaf samples of L. acidissima from various places located in Western Ghats, India wherein the aerial parts were distilled through hydrodistillation with the Clevenger-type apparatus for oil extracts. The study employed gas chromatographic analysis to the essential oil samples which indicates that primary components include β-pinene, limonene, and methyl chavicol.

A letter to the editor is presented that presents a case study of a 68-year-old man with two months progressive dysphagia and was diagnosed of having esophageal cancer.

The article features Melocanna baccifera (M. baccifer), a sympodial bamboo with 20 meters height in India. It produces groves of widely spaced culms as well as considered as an aggressive colonizer and often forms the dominant vegetation on the tropical hills. It offers information on the flowering cycle of the bamboo, which occur in several northeastern states in 2004, including Manipur, Meghalaya and Tripura.

The article reports on the use of turmeric plants in making medicine, perfume and aromatherapy items. It features several pharmacological activities, including antimicrobial, anticancer and hepato-protective, due to the presence of curcumin in the rhizome and essential oil found in the rhizomes and leaves. Moreover, it explores an alternative method of essential oil production from leaves of in vitro-grown turmeric plants through biotechnological intervention.