Laboratory and telescope use of the NICMOS2 128 x 128 HgCdTe array

The second generation of Hubble Space Telescope (HST) instruments will include a near-infrared instrument. This choice has driven the development of near-infrared arrays to larger sizes and lower read noises. Rockwell International has delivered an array for use in the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) instrument; this array has been dubbed NICMOS2. NICMOS2 is a 128x128 array of HgCdTe diodes In-bonded to a switched MOSFET readout. The readout was specifically designed for astronomical use with the HST requirement of low read noise a prime goal. These arrays use detector material which is similar to that used by Rockwell in previous arrays (e.g., HgCdTe produced on a sapphire substrate), but the NICMOS2 devices differ substantially from other 128x128 arrays produced by Rockwell in having a read noise of only 30 electrons when read out using appropriate correlated sampling. NICMOS2 has now been characterized in the laboratory, and it has been used on groundbased telescopes

Success Probability of Multiple-Preamble Based Single-Attempt Random Access to Mobile Networks

In this letter, we analyse the trade-off between collision probability and code-ambiguity, when devices transmit a sequence of preambles as a codeword, instead of a single preamble, to reduce collision probability during random access to a mobile network. We point out that the network may not have sufficient resources to allocate to every possible codeword, and if it does, then this results in low utilisation of allocated uplink resources. We derive the optimal preamble set size that maximises the probability of success in a single attempt, for a given number of devices and uplink resources

The inner circumstellar disk of the UX Ori star V1026 Sco

The UX Ori type variables (named after the prototype of their class) are intermediate-mass pre-main sequence objects. One of the most likely causes of their variability is the obscuration of the central star by orbiting dust clouds. We investigate the structure of the circumstellar environment of the UX~Ori star V1026 Sco (HD 142666) and test whether the disk inclination is large enough to explain the UX Ori variability. We observed the object in the low-resolution mode of the near-infrared interferometric VLTI/AMBER instrument and derived H- and K-band visibilities and closure phases. We modeled our AMBER observations, published Keck Interferometer observations, archival MIDI/VLTI visibilities, and the spectral energy distribution using geometric and temperature-gradient models. Employing a geometric inclined-ring disk model, we find a ring radius of 0.15 +- 0.06 AU in the H band and 0.18 +- 0.06 AU in the K band. The best-fit temperature-gradient model consists of a star and two concentric, ring-shaped disks. The inner disk has a temperature of 1257^{+133}_{-53} K at the inner rim and extends from 0.19 +- 0.01 AU to 0.23 +- 0.02 AU. The outer disk begins at 1.35^{+0.19}_{-0.20} AU and has an inner temperature of 334^{+35}_{-17} K. The derived inclination of 48.6^{+2.9}_{-3.6}deg approximately agrees with the inclination derived with the geometric model (49 +- 5deg in the K band and 50 +- 11deg in the H band). The position angle of the fitted geometric and temperature-gradient models are 163 +- 9deg (K band; 179 +- 17deg in the H band) and 169.3^{+4.2}_{-6.7}deg, respectively. The narrow width of the inner ring-shaped model disk and the disk gap might be an indication for a puffed-up inner rim shadowing outer parts of the disk. The intermediate inclination of ~50deg is consistent with models of UX Ori objects where dust clouds in the inclined disk obscure the central star

Sustainable brand positioning by container shipping firms: Evidence from social media communications

This study contributes to shipping research by profiling container shipping lines with respect to their sustainability related brand positioning strategies through their social media communications. Longitudinal content analysis is combined with multiple correspondence analysis (MCA) to map branding strategies of selected lines in relation to the triple bottom line (TBL) dimensions and functional versus emotional sustainability benefits. Results indicate that shipping lines position their brands closer to either economic or environmental sustainability where a win-win focus in the messages is highly prevalent. Social sustainability constitutes a market gap and an opportunity for the sustainability positioning of these brands. Furthermore, despite a few that recognize the potential in emotional benefits, majority of the lines use functional sustainability benefits in brand positioning. Emotional sustainability benefits provide wider opportunities with respect to brand differentiation and effective customer engagement in shipping lines’ sustainability initiatives

An ICT-based start-up entering maritime logistics networks: facilitation of value cocreation patterns

Purpose: This study aims to explore how a start-up entering maritime logistics networks (MLNs) in the container shipping industry integrates resources underlying value cocreation patterns in these networks. Design/methodology/approach: The paper is based on a single case study of a technological start-up, providing tracking, tracing and other information services to MLN members using internet-based software. An interorganizational theory perspective informs the case study to unveil the resource integration for value cocreation in the network. Findings: The start-up holds multiple resource interaction roles and the start-up’s involvement enables the creation of new knowledge resources, which facilitate new revenue streams and manage resource dependencies. Hence, the findings indicate that the start-up changes value cocreation patterns in the network by reconfiguring and integrating existing resources so that the service is customized for various customers, including shippers and freight forwarders. Practical implications: The results provide insights about how technological start-ups can unlock resources within MLNs. Originality/value: The study extends previous studies on resource roles in business networks and shows how start-ups can perform multiple roles simultaneously within these networks. In addition, the study contributes to the literature by studying information and knowledge as resources configured in different ways in a unique network setting

Resurrection of Ornithogalum brevipedicellatum (Asparagaceae) with morphological and molecular data

This study evaluates Ornithogalum brevipedicellatum, which was previously accepted as a synonym of O. oligophyllum, as a separate distinct species and discusses the similarities and differences between O. brevipedicellatum and its related species (O. oligophyllum and O. pamphylicum). Similarities and differences among these species were identified by morphological and molecular studies. The leaf morphology and inflorescence of O. brevipedicellatum and O. pamphylicum are similar to each other, and in terms of these features, they show differences from O. oligophyllum. Some diagnostic characteristics are quite different in O. brevipedicellatum and O. pamphylicum, such as the size of tepals, length of fruiting pedicels and style. Morphological data were supported by the results obtained from molecular studies. According to a dendrogram obtained by molecular studies, O. brevipedicellatum and O. pamphylicum are similar. O. oligophyllum is more closely related to O. pyrenaicum used as an out-group. Additionally, the seeds of O. brevipedicellatum were examined with the use of scanning electron microscopy

Contribution of heme oxygenase 2 to blood pressure regulation in response to swimming exercise and detraining in spontaneously hypertensive rats

Background: We aimed to determine the effects of exercise followed by detraining on systolic blood pressure (SBP), heme oxygenase 2 (HO-2) expression, and carboxyhemoglobin (COHb) concentration in spontaneously hypertensive rats (SHR) to explain the role of carbon monoxide (CO) in this process. Material/Methods: Animals were randomized into exercised and detrained groups. Corresponding sedentary rats were grouped as Time 1–2. Swimming of 60 min/5 days/week for 10 weeks was applied. Detraining rats discontinued training for an additional 5 weeks. Gene and protein expressions were determined by real-time PCR and immunohistochemistry. Results: Aorta HO-2 histological scores (HSCORE) of hypertensive rats were lower, while SBP was higher. Swimming caused enhancement of HO-2 immunostaining in aorta endothelium and adventitia of SHR. Exercise induced elevation of blood COHb index in SHR. Synchronous BP lowering effect of exercise was observed. HO-2 mRNA expression, HSCORE, and blood COHb index were unaltered during detraining, while SBP was still low in SHR. Conclusions: CO synthesized by HO-2 at least partly plays a role in SBP regulation in the SHR-and BP-lowering effect of exercise. Regular exercise with short-term pauses may be advised to both hypertensives and individuals who are at risk. © Med Sci Monit

A hierarchical method for multi-class support vector machines

We introduce a framework, which we call Divide-by-2 (DB2), for extending support vector machines (SVM) to multi-class prob-lems. DB2 offers an alternative to the stan-dard one-against-one and one-against-rest al-gorithms. For an N class problem, DB2 pro-duces an N − 1 node binary decision tree where nodes represent decision boundaries formed by N−1 SVM binary classifiers. This tree structure allows us to present a gener-alization and a time complexity analysis of DB2. Our analysis and related experiments show that, DB2 is faster than one-against-one and one-against-rest algorithms in terms of testing time, significantly faster than one-against-rest in terms of training time, and that the cross-validation accuracy of DB2 is comparable to these two methods. 1