A search for rotating radio transients and fast radio bursts in the Parkes high-latitude pulsar survey

Discoveries of rotating radio transients and fast radio bursts (FRBs) in pulsar surveys suggest that more of such transient sources await discovery in archival data sets. Here we report on a single-pulse search for dispersed radio bursts over a wide range of Galactic latitudes (|b| < $60^{\circ}$) in data previously searched for periodic sources by Burgay et al. We re-detected 20 of the 42 pulsars reported by Burgay et al. and one rotating radio transient reported by Burke-Spolaor. No FRBs were discovered in this survey. Taking into account this result, and other recent surveys at Parkes, we corrected for detection sensitivities based on the search software used in the analyses and the different backends used in these surveys and find that the all-sky FRB event rate for sources with a fluence above 4.0 Jy ms at 1.4 GHz to be ${\cal R} = 4.4^{+5.2}_{-3.1} \times 10^3$ FRBs day$^{-1}$ sky$^{-1}$, where the uncertainties represent a $99\%$ confidence interval. While this rate is lower than inferred from previous studies, as we demonstrate, this combined event rate is consistent with the results of all systematic FRB searches at Parkes to date and does not require the need to postulate a dearth of FRBs at intermediate latitudes.Comment: Accepted, 10 pages, 6 figure

Full 3D numerical analysis of a twin screw compressor by employing open-source software

The push for having more reliable and efficient positive displacement machines (both compressors and expanders) for vapor compression and power generation (e.g., ORCs) applications has moved researchers to an always more spread employment of computational fluid dynamics (CFD). In particular, twin screw compressors, because of their high efficiency compared to other compressor types, have received interest over the last years. The numerical analysis of such machines is challenging: the deforming working chambers are very difficult to be correctly replicated. The relative motion of the rotors and the variation of the gaps during machine operation are few of the major difficulties in implementing reliable CFD models. A custom mesh generation algorithm is therefore often required for sumulating the machine operation. In this work, SCORG-V5.2.2 was used to generate the meshes of the deforming domain around rotating parts of the machines. The open-source software OpenFOAM-v1606+ is then employed to compute the flow field associated with the operation of the twin screw. The coupling of the two tools has been carried out in this work, applying the methodology to a twin screw machine

Comparative study of Image Fusion Methods: A Review

As the size and cost of sensors decrease, sensor networks are increasingly becoming an attractive method to collect information in a given area. However, one single sensor is not capable of providing all the required information,either because of their design or because of observational constraints. One possible solution to get all the required information about a particular scene or subject is data fusion.. A small number of metrics proposed so far provide only a rough, numerical estimate of fusion performance with limited understanding of the relative merits of different fusion schemes. This paper proposes a method for comprehensive, objective, image fusion performance characterization using a fusion evaluation framework based on gradient information representation. We give the framework of the overallnbsp system and explain its USAge method. The system has many functions: image denoising, image enhancement, image registration, image segmentation, image fusion, and fusion evaluation. This paper presents a literature review on some of the image fusion techniques for image fusion like, Laplace transform, Discrete Wavelet transform based fusion, Principal component analysis (PCA) based fusion etc. Comparison of all the techniques can be the better approach fornbsp future research

Peptide microarray-based characterization of antibody responses to host proteins after bacille Calmette-Guerin vaccination

BACKGROUND: Bacille Calmette–Guérin (BCG) is the world’s most widely distributed vaccine, used against tuberculosis (TB), in cancer immunotherapy, and in autoimmune diseases due to its immunomodulatory properties. To date, the effect of BCG vaccination on antibody responses to host proteins has not been reported. High-content peptide microarrays (HCPM) offer a unique opportunity to gauge specific humoral immune responses. METHODS: The sera of BCG-vaccinated healthy adults were tested on a human HCPM platform (4953 randomly selected epitopes of human proteins) to detect specific immunoglobulin gamma (IgG) responses. Samples were obtained at 56, 112, and 252 days after vaccination. Immunohistology was performed on lymph node tissue from patients with TB lymphadenitis. Results were analysed with a combination of existing and novel statistical methods. RESULTS: IgG recognition of host peptides exhibited a peak at day 56 post BCG vaccination in all study subjects tested, which diminished over time. Primarily, IgG responses exhibited increased reactivity to ion transporters (sodium, calcium channels), cytokine receptors (interleukin 2 receptor β (IL2Rβ), fibroblast growth factor receptor 1 (FGFR1)), other cell surface receptors (inositol, somatostatin, angiopoeitin), ribonucleoprotein, and enzymes (tyrosine kinases, phospholipase) on day 56. There was decreased IgG reactivity to transforming growth factor-beta type 1 receptor (TGFβR1) and, in agreement with the peptide microarray findings, immunohistochemical analysis of TB-infected lymph node samples revealed an overexpression of TGFβR in granulomatous lesions. Moreover, the vesicular monoamine transporter (VMAT2) showed increased reactivity on days 112 and 252, but not on day 56 post-vaccination. IgG to interleukin 4 receptor (IL4R) showed increased reactivity at 112 days post-vaccination, while IgG to IL2Rβ and FGFR1 showed decreased reactivity on days 112 and 252 as compared to day 56 post BCG vaccination. CONCLUSIONS: BCG vaccination modifies the host’s immune landscape after 56 days, but this imprint changes over time. This may influence the establishment of immunological memory in BCG-vaccinated individuals

AN OVERVIEW ON CARBON NANOTUBES

ABSTRACT: In different fields like semiconductors, field emission, conductive plastics, energy storage, conductive adhesives and connectors, molecular electronics, thermal materials carbon nanotubes are applicable. Carbon nanotubes are generally produced by three main techniques: arc discharge, laser ablation, chemical vapour deposition. In arc discharge, a vapour is created by an arc discharge between two carbon electrodes with or without catalyst. Nanotubes self-assemble from the resulting carbon vapour. In the laser ablation technique, a high-power laser beam impinges on a volume of carbon -containing feedstock gas (methane or carbon monoxide). At the moment, laser ablation produces a small amount of clean nanotubes, whereas arc discharge methods generally produce large quantities of impure material. In general, chemical vapour deposition (CVD) results in Multi Walled Nanotubes or poor quality Single Walled Nanotubes. The SWNTs produced with CVD have a large diameter range, which can be poorly controlled. But on the other hand, this method is very easy to scale up, what favours commercial production

Allelopathic effect of Dendrocalamus stocksii (Munro.) on growth and yield of ground nut (Arachis hypogaea)

The present study was conducted to assess allelopathic effect of Dendrocalamus stocksii (Munro.)&nbsp;on&nbsp;the growth and yield of ground nut (Arachis hypogaea). Bamboo leaf leachate was prepared by soaking the dry leaves in tap water for 24 hours in a ratio of 1:10 w/v.&nbsp; Using prepared leachate as stock solution the leachate of various concentrations viz., control (0%), 25, 50 and 75 and 100 per cent were prepared by adding tap water accordingly. The results revealed the concentration-dependent significant (p=0.05) inhibitory effect of bamboo leaf leachates on the germination, radicle and plumule length of groundnut in laboratory condition. The leaf leachate of 100% concentration reduced down the germination percentage (56%), radicle length (3.00 cm) and plumule length (5.36 cm) as compared to control treatment where the germination percentage (86.66%), radicle length (5.02 cm) and plumule length (12.08 cm) were maximum. Similarly, the allelopathic effect of leaf leachate on transplanted seedlings of groundnut in prepared beds inside the poly house were significantly (p=0.05) inhibitory for the test seed weight and straw yield/ha. Minimum test seed weight (430.33 g) was recorded in the treatment of 25 % concentration as compared to control (601.33 g) and straw yield per hectare in the treatment of 100 % concentration (2421.1 kg/ha) as compared to control (4729.4 kg/ha). However, the non- significant effect of leaf leachate was observed on other yield parameters i.e., number of tillers per plant, number of pods / plant, test seed weight, seed yield per plant, number of seeds per pod and grain yield per ha. Finally, it is concluded that the harmful effect of leaf leachates of Dendrocalamus stocksii is more prominent in early stage of germination, emergence of radicle and plumule etc., rather than after transplanting; it is recommended to avoid the effect of these allelochemicals in early growth stage in field condition

Application of Radiation Sources in Steel Industry in India

The applications of ionizing radiation sources (radioisotope and X-ray)in India have registered the phenomenal growth for beneficial uses in medicine, ind-ustry, agriculture, research and training. In industry, there are different applications of radioisotopes viz. tracer studies, nucleonic control systems(NCS), i.e. nucleonic gauges; radiography for non-destructive testing(NDT) and radiation processing of food and health care products. With the obvious beneficial use of radiation sources, there is also concern about the likehood of harmful effects of radiation, which necissitates the eff-ecive regulatory control over radiation sources. The compr-ehensive regulatory programme has been estabilished in the country and the requirement of licence for handling of radiation sources in India is a statutory requirement as per Atomic Energy (Radiation Protection) Rule, 2004. The NCS find many non-destructive applications in steel industry, such as in situ determination of thickness of steel plate(s); measurement of density and determination of elemental composition of materials; level measurements; control of process material in closed containers i.e. mould level measurement; moisture content in blast fur-nace; analysis of ores and minerals. The type of radiation used includes gamma, X-rays, XRF and neutron sources with activity varying from several MBq to GBq. There are about 1500 number of NCS installed and operated in around 150 numbers of steel and allied industries all over the country. The NDT by radiation sources play important role in verifying integrity of steel structure. The radiation equipment (i.e. NCS and radiography device) with several built-in-saftey features and trained/certified operating staff ensures safe handling and use of radiation sources in industry. While handling of radiation sources, unusual occurrences do occur

Dispelling urban myths about default uncertainty factors in chemical risk assessment - Sufficient protection against mixture effects?

© 2013 Martin et al.; licensee BioMed Central LtdThis article has been made available through the Brunel Open Access Publishing Fund.Assessing the detrimental health effects of chemicals requires the extrapolation of experimental data in animals to human populations. This is achieved by applying a default uncertainty factor of 100 to doses not found to be associated with observable effects in laboratory animals. It is commonly assumed that the toxicokinetic and toxicodynamic sub-components of this default uncertainty factor represent worst-case scenarios and that the multiplication of those components yields conservative estimates of safe levels for humans. It is sometimes claimed that this conservatism also offers adequate protection from mixture effects. By analysing the evolution of uncertainty factors from a historical perspective, we expose that the default factor and its sub-components are intended to represent adequate rather than worst-case scenarios. The intention of using assessment factors for mixture effects was abandoned thirty years ago. It is also often ignored that the conservatism (or otherwise) of uncertainty factors can only be considered in relation to a defined level of protection. A protection equivalent to an effect magnitude of 0.001-0.0001% over background incidence is generally considered acceptable. However, it is impossible to say whether this level of protection is in fact realised with the tolerable doses that are derived by employing uncertainty factors. Accordingly, it is difficult to assess whether uncertainty factors overestimate or underestimate the sensitivity differences in human populations. It is also often not appreciated that the outcome of probabilistic approaches to the multiplication of sub-factors is dependent on the choice of probability distributions. Therefore, the idea that default uncertainty factors are overly conservative worst-case scenarios which can account both for the lack of statistical power in animal experiments and protect against potential mixture effects is ill-founded. We contend that precautionary regulation should provide an incentive to generate better data and recommend adopting a pragmatic, but scientifically better founded approach to mixture risk assessment. © 2013 Martin et al.; licensee BioMed Central Ltd.Oak Foundatio

Intelligent diagnostic feedback for online multiple-choice questions

When students attempt multiple-choice questions (MCQs) they generate invaluable information which can form the basis for understanding their learning behaviours. In this research, the information is collected and automatically analysed to provide customized, diagnostic feedback to support students’ learning. This is achieved within a web-based system, incorporating the snap-drift neural network based analysis of students’ responses to MCQs. This paper presents the results of a large trial of the method and the system which demonstrates the effectiveness of the feedback in guiding students towards a better understanding of particular concepts