A payload to evaluate photodiodes for the detection of soft and hard x rays in a space environment using a Get Away Special

We propose to use the Get Away Special (GAS) facility to evaluate P-intrinsic-N (PIN) detectors and avalanche photodiodes (APD's) for the detection of both solar and nonsolar soft and hard x rays. We would like to fly both types of silicon detectors for the direct detection of the x ray photons in the energy range from 1 to 30 keV with an energy resolution of about 1 keV. We would also like to use both types of photodiodes viewing CsI(Tl) scintillators to extend the energy range up to 1 MeV with -6 percent resolution at 660 keV. Solar flares would be detected with this instrumentation during periods of solar pointing providing high energy resolution spectra with high time resolution. Similar data would be obtained in the scanning mode on nonsolar transient and steady x ray sources with the same instrumentation. A commandable door over the detectors would be required to allow measurements to be made as low as 1 keV

Mirizzi Syndrome Type II: Is Laparoscopic Cholecystectomy Justified?

Mirizzi syndrome type II is an uncommon cause of obstructive jaundice caused by an inflammatory response to an impacted gallstone in Hartmann's pouch or the cystic duct with a resultant cholecystocholedochal fistula. Two cases of Mirizzi syndrome type II are presented. Clinically only one patient had jaundice and endoscopic retrograde cholangiopancreatogram (ERCP) established a preoperative diagnosis of Mirizzi syndrome. The other patient's diagnosis of Mirizzi syndrome was made intraoperatively

New room temperature high resolution solid-state detector (CdZnTe) for hard x rays and gamma rays

The new CdZnTe high 'Z' material represents a significant improvement in detectors for high energy photons. With the thicknesses available, photons up to 100 keV can be efficiently detected. This material has a wide band gap of 1.5 - 2.2 eV which allows it to operate at room temperature while providing high spectral resolution. Results of resolution evaluations are presented. This detector can be used for high resolution spectral measurements of photons in x-ray and gamma-ray astronomy, offering a significant reduction in the weight, power, and volume of the detector system compared to more conventional detector types such as scintillation counters. In addition, the detector will have the simplicity and reliability of solid-state construction. The CdZnTe detector, as a new development, has not yet been evaluated in space. The Get Away Special program can provide this opportunity

Persistent time intervals between features in solar flare hard X-ray emission

Several solar hard X-ray events (greater than 100 keV) were observed simultaneously with identical instruments on the Venera 11, 12, 13, 14, and Prognoz spacecraft. High time resolution (= 2 ms) data were stored in memory when a trigger occurred. The observations of modulation are presented with a period of 1.6 s for the event on December 3, 1978. Evidence is also presented for fast time fluctuations from an event on November 6, 1979, observed from Venera 12 and another on September 6, 1981, observed from the Solar Maximum Mission. Power spectrum analysis, epoch folding, and Monte Carlo simulation were used to evaluate the statistical significance of persistent time delays between features. The results are discussed in light of the MHD model proposed by Zaitsev and Stepanov

The pivotal role of student assessment in work-integrated learning

Work-integrated learning (WIL) is proliferating in university courses across many countries. Like many educational practices, students’ experience of it is shaped by the assessment processes adopted. Does assessment support or inhibit what WIL seeks to foster? To explore how students experience assessment in WIL, a small-scale investigation was undertaken across faculties in a UK university. Students who had recently undertaken WIL in contexts where it was either tightly coupled or loosely coupled to their programme of study undertook a drawing-stimulated interview about their placement and the role of assessment within it. A thematic analysis was used to discern key themes in student responses. Key issues identified were the importance of assessment in scaffolding learning, the multiple roles of university and workplace staff in assessment, the extent to which assessment practices promote students seeing themselves as becoming practitioners and the reflexive effects of assessment on learning. The paper discusses the implications of these issues for the design of WIL activities

Bioefficacy of Imidacloprid 350 SC against sucking insect-pests in chilli (Capsicum annum L.)

A field experiment was conducted in a RBD at Horticulture farm, Rajasthan College of Agriculture, Udaipur to evaluate the bioefficacy of Imidacloprid 350 SC at 100, 125 and 150 ml/ha against sucking pests of chilli during Kharif, 2013 and 2014. The highest reduction in the population of aphid, jassids and thrips in chilli was recorded in case of two spray of Imidacloprid 350 SC at 150 ml/ha and also recorded highest marketable yield of 161.25 and 164.88 q/ha during 2013 and 2014, respectively. It was found at par to Imidacloprid 350 SC at 125 ml/ha

Three precise gamma-ray burst source locations

The precise source regions of three moderately intense gamma ray bursts are derived. These events were observed with the first interplanetary burst sensor network. The optimum locations of the detectors, widely separated throughout the inner solar system, allowed for high accuracy, over-determined source fields of size 0.7 to 7.0 arc-min(2). All three locations are at fairly high galactic latitude in regions of low source confusion; none can be identified with a steady source object. Archived photographs were searched for optical transients that are able to be associated with these source fields; one such association was made

The Spitzer Archival Far-InfraRed Extragalactic Survey

We present the Spitzer Archival Far-InfraRed Extragalactic Survey (SAFIRES). This program produces refined mosaics and source lists for all far-infrared extragalactic data taken during the more than six years of the cryogenic operation of the Spitzer Space Telescope. The SAFIRES products consist of far-infrared data in two wavelength bands (70 um and 160 um) across approximately 180 square degrees of sky, with source lists containing far-infrared fluxes for almost 40,000 extragalactic point sources. Thus, SAFIRES provides a large, robust archival far-infrared data set suitable for many scientific goals.Comment: 7 pages, 6 figures, published in ApJ

Contextual Object Detection with a Few Relevant Neighbors

A natural way to improve the detection of objects is to consider the contextual constraints imposed by the detection of additional objects in a given scene. In this work, we exploit the spatial relations between objects in order to improve detection capacity, as well as analyze various properties of the contextual object detection problem. To precisely calculate context-based probabilities of objects, we developed a model that examines the interactions between objects in an exact probabilistic setting, in contrast to previous methods that typically utilize approximations based on pairwise interactions. Such a scheme is facilitated by the realistic assumption that the existence of an object in any given location is influenced by only few informative locations in space. Based on this assumption, we suggest a method for identifying these relevant locations and integrating them into a mostly exact calculation of probability based on their raw detector responses. This scheme is shown to improve detection results and provides unique insights about the process of contextual inference for object detection. We show that it is generally difficult to learn that a particular object reduces the probability of another, and that in cases when the context and detector strongly disagree this learning becomes virtually impossible for the purposes of improving the results of an object detector. Finally, we demonstrate improved detection results through use of our approach as applied to the PASCAL VOC and COCO datasets

Packet Size Optimization for Cognitive Radio Sensor Networks Aided Internet of Things

Cognitive Radio Sensor Networks (CRSN) is state of the art communication paradigm for power constrained short range data communication. It is one of the potential technology adopted for Internet of Things (IoT) and other futuristic Machine to Machine (M2M) based applications. Many of these applications are power constrained and delay sensitive. Therefore, CRSN architecture must be coupled with different adaptive and robust communication schemes to take care of the delay and energy-efficiency at the same time. Considering the tradeoff that exists in terms of energy efficiency and overhead delay for a given data packet length, it is proposed to transmit the physical layer payload with an optimal packet size (OPS) depending on the network condition. Furthermore, due to the cognitive feature of CRSN architecture overhead energy consumption due to channel sensing and channel handoff plays a critical role. Based on the above premises, in this paper we propose a heuristic exhaustive search based Algorithm-1 and a computationally efficient suboptimal low complexity Karuh-Kuhn- Tucker (KKT) condition based Algorithm-2 to determine the optimal packet size in CRSN architecture using variable rate m-QAM modulation. The proposed algorithms are implemented along with two main cognitive radio assisted channel access strategies based on Distributed Time Slotted-Cognitive Medium Access Control (DTS-CMAC) and Centralized Common Control Channel based Cognitive Medium Access Control (CC-CMAC) and their performances are compared. The simulation results reveals that proposed Algorithm-2 outperforms Algorithm-1 by a significant margin in terms of its implementation time. For the exhaustive search based Algorithm-1 the average time consumed to determine OPS for a given number of cognitive users is 1.2 seconds while for KKT based Algorithm-2 it is of the order of 5 to 10 ms. CC-CMAC with OPS is most efficient in terms of overall energy consumption but incurs more delay as compared to DTS-CMAC with OPS scheme