A Word to the WISE: Confusion is Unavoidable for WISE-selected Infrared Excesses

Stars with excess infrared radiation from circumstellar dust are invaluable for studies of exoplanetary systems, informing our understanding on processes of planet formation and destruction alike. All-sky photometric surveys have made the identification of dusty infrared excess candidates trivial, however, samples that rely on data from WISE are plagued with source confusion, leading to high false positive rates. Techniques to limit its contribution to WISE-selected samples have been developed, and their effectiveness is even more important as we near the end-of-life of Spitzer, the only facility capable of confirming the excess. Here, we present a Spitzer follow-up of a sample of 22 WISE-selected infrared excess candidates near the faint-end of the WISE detection limits. Eight of the 22 excesses are deemed the result of source confusion, with the remaining candidates all confirmed by the Spitzer data. We consider the efficacy of ground-based near-infrared imaging and astrometric filtering of samples to limit confusion among the sample. We find that both techniques are worthwhile for vetting candidates, but fail to identify all of the confused excesses, indicating that they cannot be used to confirm WISE-selected infrared excess candidates, but only to rule them out. This result confirms the expectation that WISE-selected infrared excess samples will always suffer from appreciable levels of contamination, and that care should be taken in their interpretation regardless of the filters applied.Comment: 13 pages, 4 Figures; Accepted for publication in Ap

2D Full-Wave Simulation of Waves in Space and Tokamak Plasmas

Simulation results using a 2D full-wave code (FW2D) for space and NSTX fusion plasmas are presented. The FW2D code solves the cold plasma wave equations using the finite element method. The wave code has been successfully applied to describe low frequency waves in planetary magnetospheres (i.e., dipole geometry) and the results include generation and propagation of externally driven ultra-low frequency waves via mode conversion at Mercury and mode coupling, refraction and reflection of internally driven field-aligned propagating left-handed electromagnetic ion cyclotron (EMIC) waves at Earth. In this paper, global structure of linearly polarized EMIC waves is examined and the result shows such resonant wave modes can be localized near the equatorial plane. We also adopt the FW2D code to tokamak geometry and examine radio frequency (RF) waves in the scape-off layer (SOL) of tokamaks. By adopting the rectangular and limiter boundary, we compare the results with existing AORSA simulations. The FW2D code results for the high harmonic fast wave heating case on NSTX with a rectangular vessel boundary shows excellent agreement with the AORSA code

Communicating in designing an oral repository for rural African villages

We describe designing an asynchronous, oral repository and sharing system that we intend to suit the needs and practices of rural residents in South Africa. We aim to enable users without access to personal computers to record, store, and share information within their Xhosa community using cellphones and a tablet PC combined with their existing face-to-face oral practices. Our approach recognises that systems are more likely to be effective if the design concept and process build on existing local communication practices as well as addressing local constraints, e.g. cost. Thus, we show how the objectives for the system emerged from prolonged research locally and how we communicated insights, situated in the community, into the process of design and development in a city-based lab. We discuss how we integrated understandings about communication between situated- and localresearchers and designers and developers and note the importance of recognising and centralising subtle differences in our perception of acts of oral communication. We go on to show how the materiality of the software, the tablet form factor, and touch interaction style played into our collaborative effort in conceiving the design.Department of HE and Training approved lis

Artificial intelligence in diabetic retinopathy screening: clinical assessment using handheld fundus camera in a real-life setting

Aim: Diabetic retinopathy (DR) represents the main cause of vision loss among working age people. A prompt screening of this condition may prevent its worst complications. This study aims to validate the in-built artificial intelligence (AI) algorithm Selena+ of a handheld fundus camera (Optomed Aurora, Optomed, Oulu, Finland) in a first line screening of a real-world clinical setting. Methods: It was an observational cross-sectional study including 256 eyes of 256 consecutive patients. The sample included both diabetic and non-diabetic patients. Each patient received a 50°, macula centered, non-mydriatic fundus photography and, after pupil dilation, a complete fundus examination by an experienced retina specialist. All images were after analyzed by a skilled operator and by the AI algorithm. The results of the three procedures were then compared. Results: The agreement between the operator-based fundus analysis in bio-microscopy and the fundus photographs was of 100%. Among the DR patients the AI algorithm revealed signs of DR in 121 out of 125 subjects (96.8%) and no signs of DR 122 of the 126 non-diabetic patients (96.8%). The sensitivity of the AI algorithm was 96.8% and the specificity 96.8%. The overall concordance coefficient k (95% CI) between AI-based assessment and fundus biomicroscopy was 0.935 (0.891-0.979). Conclusions: The Aurora fundus camera is effective in a first line screening of DR. Its in-built AI software can be considered a reliable tool to automatically identify the presence of signs of DR and therefore employed as a promising resource in large screening campaigns

Epiretinal implant of human amniotic membrane to treat highly myopic macular hole retinal detachments: A novel surgical technique

Purpose: To describe a new surgical technique involving the use of a human amniotic membrane (hAM) epiretinal patch to treat a primary macular hole retinal detachment (MHRD) in a highly myopic patient. Methods: A 60 years old highly myopic man was referred to our clinic with a diagnosis of MHRD in his right eye. The patient was pseudophakic, with a visual acuity of counting fingers at the baseline evaluation. Pars plana vitrectomy was performed, a small retinotomy was created at the inner margin of the staphyloma, and membrane blue dual was used to obtain an adequate peeling of the inner limiting membrane. Then, a 1.5 mm diameter circular hAM patch was obtained and positioned over the macular hole with the chorion layer settled over the retina. After a complete fluid-air exchange, 20% sulfur hexafluoride gas was used as endotamponade, and the patient was asked to remain face down for three days. Results: Four weeks after surgery, optical coherence tomography (OCT) scan showed the hAM patch, visualized as a distinct hyperreflective layer well integrated with the retina. Nine months after surgery, the macular hole was closed, the retina reattached, the hAM patch was adherent to the retina, and the patient presented a best-corrected visual acuity improved to 0.7 logMar. No postoperative adverse events were registered during the follow-up. Conclusions: Epiretinal hAM implant could represent a novel surgical technique, feasible and easier compared to other current techniques used to treat MHRD in highly myopic patients

Towards a sustainable business model for rural telephony

This paper presents the work done thus far towards designing a sustainable business model for rural telephony in the community of Mankosi, located in the Eastern Cape province of South Africa. The pillars of the model are sustainability and community ownership to design both the wireless mesh network providing the telephony service and its business model. Given the airtime consumption pattern in the community, the model is based only on the provision of calls inside the community and for using solar power to charge mobile phones. Some scenarios with different usage of the telephony services and different pricing rates are explored in order to find the break even point of the network, or in case the CAPEX was provided externally, to calculate the revenues expected. These revenues could be used for projects that benefit the community at large. Although the project is in its initial phase and the community has some particularities that make it unique, the sustainable business model presented here is intended to showcase innovative ideas that could serve similar projects in other parts of the world.Telkom, Cisco, Aria Technologies, THRI

LAT Observation of GRBs: Simulations and Sensitivity Studies

The GLAST Large Area Telescope (LAT) is the next generation satellite experiment for high-energy gamma-ray astronomy. It employs a pair conversion technique to record photons in the energy range from 20 MeV to more than 300 GeV. The LAT will follow the steps from its predecessor EGRET (1991-2000), and will explore the high-energy gamma-ray sky with unprecedented capabilities. The observation of Gamma-Ray Bursts is one of the main science goal of the LAT: in this contribution we compute an estimation of the LAT sensitivity to GRB, adopting a phenomenological description of GRBs, where the high-energy emission in GRB is obtained extrapolating the observed BATSE spectrum up to LAT energies. The effect of the cosmological attenuation is included. We use the BATSE current catalog to build up our statistics

Phenotype and genotype variation in primary carnitine deficiency

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