Microwave Spectroscopy

Contains reports on five research projects.United States Army Signal Corps (Contract DA36-039-sc-74895

Performance of a megawatt-scale grid-connected solar photovoltaic power plant in Kolar District in Karnataka

A megawatt scale grid-connected photovoltaic power plant was commissioned on 27 December 2009 in Yalesandra in Kolar district in Karnataka. The Yalesandra plant is one among more than 20 such Megawatt size solar power plants in India during the past few years. The performance of this plant during its first year of operation has been discussed. The total electrical energy generated by the Yelasandra plant during 2010 was 3.34 million kWh. Although the performance of photovoltaic modules was good, there were problems associated with the inverters which led to reduction in energy generation. The impact of temperature variation of modules on their performance has been highlighted

Evidence of co-infection of chikungunya and densonucleosis viruses in C6/36 cell lines and laboratory infected Aedes aegypti (L.) mosquitoes

<p>Abstract</p> <p>Background</p> <p>Densonucleosis viruses are the etiological agents of insect's disease. We have reported the isolation of densovirus from India and its distribution among the natural populations of <it>Aedes aegypti </it>mosquitoes across the country. Since densonucleosis virus persistently infects mosquito populations, and is demonstrated to negatively affect multiplication of dengue virus in <it>Aedes albopictus</it>, it would be interesting to study if this virus has a role in determining the susceptibility of the vector mosquito <it>Ae. aegypti </it>to chikugunya virus.</p> <p>Methods</p> <p>Mosquito cell lines and adult <it>Ae. aegypti </it>mosquitoes infected with densovirus were superinfected with Chikungunya virus and both the viruses were quantitated by determining their genomic copy number by real time amplification. Comparison was made between the log of genomic copy numbers of the viruses in the presence and absence of each other.</p> <p>Results</p> <p>The log of copy number of the viruses did not vary due to co-infection. Even though the RNA copy number of chikungunya virus increased over the period of time, no change was observed in the RNA copy number between the control and the co-infected group on any given day. Similarly, DNA copy number of densovirus also remained unchanged between the control and the co-infected groups.</p> <p>Conclusion</p> <p>Chikungunya virus neither stimulates the replication of densovirus nor is its own replication suppressed due to co-infection. <it>Ae. aegypti </it>mosquitoes with densovirus infection were as susceptible to infection by chikungunya virus as the uninfected mosquitoes.</p

Alcohol dehydrogenase and invertase activities in ethanol tolerant yeasts

Two ethanol tolerant yeast isolates of Saccharomyces cerevisiae Y-10 and Saccharomyces cerevisiae Y-7 were compared for their invertase (EC 3.2.1.26, β-fructofuranoside fructohydrolase) and alcohol dehydrogenase (ADH, EC 1.1.1.1, alcohol:NAD oxidoreductase) activities as well as ethanol productivity. The isolates showed significantly higher ethanol productivities compared to the standard strain Saccharomyces uvarum and other yeast strains tested. The alcohol dehydrogenase activity was 40–100% higher in the isolates than S. uvarum and the percentage change varied depending on the growth conditions. However, this was not true for invertase activity. Both the isolates showed a similar ADH isozyme pattern in contrast to S. uvarum. The results suggested that a better correlation between ADH activity and ethanol productivity could be drawn only after extensive studies on the kinetic parameters of the individual isozymes

Sustainability of different cropping systems under varying sowing dates in Marathwada region

The Held experiments were carried out at Instructional Farm. AIC’RP on Dry land Agriculture, Marathwada Agricultural University. Parbhani during the rainy season o f 2001-2005 on eight different cropping systems consisting o f important food, pulse and oilseed crops o f Marathwada region under varied weather conditions. The results revealed that intercropping o f sorghum (CSH-9) t pigeonpea. pear m illet pigeonpea and castor + soybean sown in 26 meteorological w e eM M W ) produced the highest grain yield and average productivity o f the system during all the years o f experimentation as compared to rest o f the cropping systems. Similarly, castor soybean produced the highest sorghum grain equivalent which was at par with soybean + pigeonpea. Arhorhtm cotton + soybean and cotton (N I111-44) + soybean. The sowing o f all the crops and cropping systems on 26 MW recorded significantly highest sustainable yield index (0.^2) as compared to sowing o f all cropping systems on delayed sowing dates

Fabrication of Sawfish photonic crystal cavities in bulk diamond

Color centers in diamond are quantum systems with optically active spin-states that show long coherence times and are therefore a promising candidate for the development of efficient spin-photon interfaces. However, only a small portion of the emitted photons is generated by the coherent optical transition of the zero-phonon line (ZPL), which limits the overall performance of the system. Embedding these emitters in photonic crystal cavities improves the coupling to the ZPL photons and increases their emission rate. Here, we demonstrate the fabrication process of "Sawfish" cavities, a design recently proposed that has the experimentally-realistic potential to simultaneously enhance the emission rate by a factor of 46 and couple photons into a single-mode fiber with an efficiency of 88%. The presented process allows for the fabrication of fully suspended devices with a total length of 20.5 $\mu$m and features size as small as 40 nm. The optical characterization shows fundamental mode resonances that follow the behavior expected from the corresponding design parameters and quality (Q) factors as high as 3825. Finally, we investigate the effects of nanofabrication on the devices and show that, despite a noticeable erosion of the fine features, the measured cavity resonances deviate by only 0.9 (1.2)% from the corresponding simulated values. This proves that the Sawfish design is robust against fabrication imperfections, which makes it an attractive choice for the development of quantum photonic networks.Comment: 7 pages, 9 figure

Time-Lapse Analysis of Human Embryonic Stem Cells Reveals Multiple Bottlenecks Restricting Colony Formation and Their Relief upon Culture Adaptation

Summary Using time-lapse imaging, we have identified a series of bottlenecks that restrict growth of early-passage human embryonic stem cells (hESCs) and that are relieved by karyotypically abnormal variants that are selected by prolonged culture. Only a minority of karyotypically normal cells divided after plating, and these were mainly cells in the later stages of cell cycle at the time of plating. Furthermore, the daughter cells showed a continued pattern of cell death after division, so that few formed long-term proliferating colonies. These colony-forming cells showed distinct patterns of cell movement. Increasing cell density enhanced cell movement facilitating cell:cell contact, which resulted in increased proportion of dividing cells and improved survival postplating of normal hESCs. In contrast, most of the karyotypically abnormal cells reentered the cell cycle on plating and gave rise to healthy progeny, without the need for cell:cell contacts and independent of their motility patterns

Identification and single-cell functional characterization of an endodermally biased pluripotent substate in human embryonic stem cells

Human embryonic stem cells (hESCs) display substantial heterogeneity in gene expression, implying the existence of discrete substates within the stem cell compartment. To determine whether these substates impact fate decisions of hESCs we used a GFP reporter line to investigate the properties of fractions of putative undifferentiated cells defined by their differential expression of the endoderm transcription factor, GATA6, together with the hESC surface marker, SSEA3. By single-cell cloning, we confirmed that substates characterized by expression of GATA6 and SSEA3 include pluripotent stem cells capable of long-term self-renewal. When clonal stem cell colonies were formed from GATA6-positive and GATA6-negative cells, more of those derived from GATA6-positive cells contained spontaneously differentiated endoderm cells than similar colonies derived from the GATA6-negative cells. We characterized these discrete cellular states using single-cell transcriptomic analysis, identifying a potential role for SOX17 in the establishment of the endoderm-biased stem cell state

Embedding creativity in the university computing curriculum

We explore the need for embedding creativity in the UK Higher Education computing curriculum and some of the challenges associated with this. We identify some of the initiatives and movements in this area and discuss some of the work that has been carried out. We then describe some of the ways we have tried to meet these challenges and reflect on our degree of success with respect to the goal of producing graduates who are fit for the myriad of job opportunities they will come across in a rapidly changing technology landscape. Finally, we make a number of recommendations

Radio-Frequency Spectroscopy

Contains reports on four research projects