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Nipah virus (NiV) outbreak occurred in Kozhikode district, Kerala, India in 2018 with a case fatality rate of 91% (21/23). In 2019, a single case with full recovery occurred in Ernakulam district. We described the response and control measures by the Indian Council of Medical Research and Kerala State Government for the 2019 NiV outbreak. The establishment of Point of Care assays and monoclonal antibodies administration facility for early diagnosis, response and treatment, intensified contact tracing activities, bio-risk management and hospital infection control training of healthcare workers contributed to effective control and containment of NiV outbreak in Ernakulam.
The high intensity anomalous OH emission which has been detected in the neighbourhood of HII regions exhibits remarkable polarization characteristics, narrow spectral features, and unusual ratios of line strengths. All of these unusual properties are generally believed to be attributable to maser action of some form. A knowledge of the structure of the emitting regions and their brightness temperature is necessary for the development of a satisfactory theory of the emission mechanism.
An extensive survey of HI absorption in the spectra of discrete radio sources has been in progress for the past three years at the Parkes radio observatory. One part of the survey comprising sources along the galactic plane north of declination —50° has recently been completed. In this communication we discuss some conclusions concerning the distances of 10 sources drawn from a preliminary analysis of the data.
Towards the end of February 1968 the astronomical world was staggered by a paper from the Milliard Radio Observatory at Cambridge announcing the discovery of an astonishing periodic phenomenon. The characteristics of the pulsating radio source—or pulsar as it came to be called—involved a fantastic multiplicity of time-scales. The duration of the individual events was measured in tens of milliseconds, the repetition rate was of the order of a second, the pulse amplitude showed drastic variations over times of seconds, minutes, hours and even months and, lastly, the stability of the basic periodicity indicated a time-scale of millions of years. A series of pulses from CP 1919, the first pulsar, is shown in Figure 1, and one notices here both the regularity of the pulses and the variation in their amplitude with time. When the individual pulses were observed on an expanded time-scale it was found that the pulses were made up of sub-pulses (Figure 2) and that there was considerable structure even down to a millisecond time-scale.
The lack of any direct measurements on the spin temperature of the neutral hydrogen in the Galaxy has led to considerable controversy in the past. Estimates of the temperature have depended strongly on whether they are based on emission or absorption studies. The widely accepted value of 125°K based on emission studies dates back to Schmidt. He adopted this figure on the premise that the maximum observed brightness temperatures in the galactic plane were in directions of high optical depth. The brightness temperature was then equated with the spin temperature on the assumption that the temperature did not fluctuate very much in a large region around the Sun.
Broiler stunning is conducted to produce a rapid onset of insensibility prior to slaughter. Though most broiler plants use electrical stunning applications, gas stunning, and low-atmosphere pressure stunning are also available for commercial applications. All three of these stunning methods are able to meet animal welfare requirements and produce meat with acceptable quality. However, each method differs in their mechanisms of stunning, rigor mortis patterns, and physical meat characteristics. In addition, gas stunning and low-atmosphere pressure stunning have received interest over the past decade as part of an effort to further improve animal welfare. Researchers have reported that gas and low-atmosphere pressure stunning both have potential advantages over electrical stunning with respect to broiler welfare and deboning time, which has been attributed to shackling post-stunning. This review paper will focus on these three stunning methods and their impact on animal welfare, physiology, rigor mortis patterns, carcass characteristics, and meat quality.
In the last decades many techniques have been proposed to manufacture thin (<50µm) silicon solar cells. The main issues in manufacturing thin solar cells are the unavailability of a reliable method to produce thin silicon foils with contained material losses (kerf-losses) and the difficulties in handling and processing such fragile foils. A way to solve both issues is to grow an epitaxial foil on top of a weak sintered porous silicon layer. The porous silicon layer is formed by electrochemical etching on a thick silicon substrate and then annealed to close the top surface. This surface is employed as seed layer for the epitaxial growth of a silicon layer which can be partially processed while attached on the substrate that provides mechanical support. Afterward, the foil can be bonded on glass, detached and further processed at module level. The efficiency of the final solar cell will depend on the quality of the epitaxial layer which, in turn, depends on the seed layer smoothness.
Several parameters can be adjusted to change the morphology and, hence, the properties of the porous layer, both in the porous silicon formation and the succeeding thermal treatment. This work focuses on the effect of the parameters that control the porous silicon formation on the structure of the porous silicon layer after annealing and, more specifically, on the roughness of the top surface. The reported analysis shows how the roughness of the seed layer can be reduced to improve the quality of the epitaxial growth.
The overarching goal of Dye Sensitized Solar Cells (DSSCs) is to improve photovoltaic performance and their long-term stability for use in practical applications because of their simple fabrication technology at a reasonable cost. The focus of this paper is to achieve cell stability and also to improve solar energy conversion efficiency experimenting with different electrolytes. The electrolyte’s role is critical to sustain the DSS cell performance over time to instill cell stability. Four different electrolytes, Iodolyte R-150, AN-50, PN-50 and MPN-100, are experimented in this work for fabricating the dye-sensitized solar cells for studying both the stability and efficiency of the DSSCs.
The electrolyte selection was made using the following key electrolyte parameters; lower viscosity for easier injection into the cell, lower vapor pressure and higher boiling point to minimize electrolyte evaporation, wide redox window to generate sufficient donating electrons to the dye, lower cost and non-toxicity. Electrolytes with higher concentration of Iodolyte were chosen for this study to widen redox potential window. These are Iodide based redox electrolytes and are made with 100 mM of tri-iodide in 3-methoxypropionitrile. The results of this investigation revealed that the cell with Iodolyte R-150 electrolyte achieved improved performance having an efficiency of 10.2% when compared to the reference cell efficiency of 8.4% with Iodolyte R-50. These cells were stabilized over a time of 4 weeks. The fill factor of the cell changed about 10% and the internal resistance decreased from 6.7 to 4.3 Ω. The results of this experiment demonstrated reduced internal resistance, and improved fill factor contributed to higher cell efficiency and stability. The results of the work presented in this paper support the argument that electrolytes with higher Iodolyte concentration can enhance the cell efficiency and stability along with scaling down of the cell size.
The Dye-sensitized Solar Cell (DSSC) has been regarded as the next-generation solar cell because of its simple and low cost fabrication process. The experiments for optimizing the cell efficiency were carried out in this work include varying the TiO2 layer thickness on the working electrode and determining the most favorable nanoparticle size in the TiO2 paste. The TiO2 electrode or working electrode was fabricated using screen printing technique with the Coatema tool with thicknesses ranging from ~20 to 66 μm. It was observed that both open circuit voltage and short circuit current were found to have measurable dependence on the TiO2 layer thickness. The open circuit voltage changed from 0.77 to 0.82 V and correspondingly the short circuit current also varied from ~19 to 23 mA/cm2 depending on the TiO2 layer thickness. Additionally, the cell with 40 μm TiO2 thickness showed 9.06% photo conversion efficiency compared to 6.4% and 8.5% efficiency obtained for the cells with 20 μm and 66 μm TiO2 thicknesses respectively. The second part of the experiment was conducted using three different nanoparticle sizes of 13 nm, 20 nm and 37nm in the TiO2 layer to identify optimum nanoparticle size by maintaining the TiO2 film thickness at 40 μm. The cell with 20 nm size nanoparticle, in combination with 40 μm TiO2 thickness showed 11.2% efficiency that is in par or slightly better than the efficiency value reported for the DSSC in the literature as of now. The work described in this paper showed best possible values for the TiO2 layer thickness and nanoparticle size in the TiO2 for obtaining improved cell efficiency of 11.2%.
We have carried out experiments on dual-damascene Cu interconnects with different lengths. We find that at short lengths, similar to Al-based interconnects, the reliability of Cubased interconnects improves. Also like Al interconnects, some short Cu segments do not form voids that cause failure before back-stresses prevent the further growth of voids. However, unlike Al-based interconnects, there is no apparent deterministic current-density line-length product (jL) for which all lines are immortal. This is related to the absence of a conducting refractory-metal overlayer in Cu-technology that can shunt current around small voids. Also unlike Al, we find that at long lengths a sub-population of Cu lines is immortal. We propose that this is the result of rupture of the thin refractory metal liner at the base of the dual-damascene Cu vias. As a consequence of this complex behavior, median times to failure and lifetime variations are minimum at intermediate line lengths.
X-ray powder diffraction data of CoSi are reported. The sample was prepared by an arc melting process and has a cubic structure (space group P213, space group No. 198) with lattice parameter a=4.4427 Å, Dx=6.591 gcm−3, Z=4, and I/Ic=1.03.
A new and improved sample holder for use with powder X-ray diffractometry has been developed. This holder is made from a semiconductor grade silicon single crystal cut perpendicular to the  axis, i.e., Si (911). This crystal meets most of the basic requirements of an ideal zero background plate, with practically no interference lines. The pattern obtained, by using this crystal as background plate, is very clean, and even very low-intensity Bragg reflections of samples can be detected easily.
Precision X-ray powder-diffraction data of pure solid C70 is reported. C70 prepared by slow evaporation of C70-in-toluene solution adopts an hcp structure (space group P63/mmc) with lattice parameters a=10.5934(10)Å and c=17.262(2)Å.
The numerous discussions that took place at the colloquium have reemphasized the primary importance of polarization observations and their interpretation for understanding the magnetospheric structure and the radiation mechanisms of pulsars. I have tried to take them into account in the summary at the end of this written version of my review of polarization phenomena, where I also attempt to address some of the questions raised by both observers and theorists as to what message polarization has for the planning of future observations and for the development of theories to explain pulsar radiation mechanisms. Because I feel it is relevant I shall begin with a little history to put things in perspective.
We report measurement of pulse profiles at 34.5 MHz of 8 pulsars using the Decameter-wave Radio Telescope at Gauribidanur, India. The dispersion measures of these pulsars range from 3 to 35 pc cm–3. None of the pulsars show any significant interpulse emission at this frequency which conflicts with earlier claims from 25-MHz observations (Bruck and Ustimenko 1976, Bruck and Ustimenko 1977a, Bruck and Ustimenko 1979). The intrinsic pulse width of PSR 1919+21 at 34.5 MHz appears to be smaller than at higher frequencies. These observations were made during the period 1984-86 and were reported by Deshpande (1987).
We discuss the distribution of source- and receiver- noise in radio synthesis images and show that the source-noise is maximum at the position of the source but also appears in the off-source region because of the sidelobes. Analytical expressions are derived for the rms noise at any location of both “total-power” and “correlation” images. We show that under certain conditions, deconvolution can remove the source noise from the off-source region in snap-shot images. Some of the results are verified experimentally.
Several attempts were made to detect the possible radio recombination lines of positronium near the galactic center. An absorption feature seen at λ6cm, in the D-configuration of the VLA was not confirmed by subsequent observations at λ6cm and λ20cm using the B and C configurations of the VLA. An observation at λ3mm using the IRAM 30m telescope also did not detect any line. On the basis of one recombination line photon for every positron (McClintock 1984), our non-detections imply an upper limit to the positron production rate of < 3.1 × 1043 s−1, within about 2″ of the galactic center.
The subject I have chosen for my talk today will come of age on the last day of this General Assembly. The first detection of the remarkable objects that we call pulsars, was on 28th November 1967 when Jocelyn Bell (now Bell-Burnell) who was working with Prof. Hewish at Cambridge discovered a new class of radio sources that put out pulses of radio radiation about once a second but with clock-like regularity. Two other major discoveries in the same decade using the radio spectrum were, of course, Quasars and the Cosmic microwave background. Those two took us to extremes in time and distance, and the amount of energy radiated, whereas the discovery of pulsars, situated near at hand by comparison, led us to extremes in the physical state of matter.
It has become more evident during the last three years that the study of interstellar matter is paramount to understand the evolution of the universe and its constituents. From observations of the present state of the interstellar medium, in our galaxy, in other galaxies, and between galaxies, it is possible to test theories of: evolution of the universe, formation and evolution of galaxies, formation and evolution of stars and of the evolution of the interstellar medium itself. The amount of information on the interstellar medium that has been gathered during the 1982-1984 period has been very large and the theoretical models that have been ellaborated to explain these observations have been very numerous, these facts show that the subject of our Commission constitutes a very active field of astronomical research.
The true nature of the association between pulsars and supernova remnants has remained an intriguing and poorly understood problem even after all these years of research on them. We attempt in this review to marshal all the evidence one has on this question, and to see what conclusions we can draw.