Simulations of astronomical imaging phased arrays

We describe a theoretical procedure for analyzing astronomical phased arrays with overlapping beams, and apply the procedure to simulate a simple example. We demonstrate the effect of overlapping beams on the number of degrees of freedom of the array, and on the ability of the array to recover a source. We show that the best images are obtained using overlapping beams, contrary to common practise, and show how the dynamic range of a phased array directly affects the image quality.Comment: 16 pages, 26 figures, submitted to Journal of the Optical Society of America

Optical Physics of Imaging and Interferometric Phased Arrays

Microwave, submillimetre-wave, and far-infrared phased arrays are of considerable importance for astronomy. We consider the behaviour imaging phased arrays and interferometric phased arrays from a functional perspective. It is shown that the average powers, field correlations, power fluctuations, and correlations between power fluctuations at the output ports of an imaging or interferometric phased array can be found once the synthesised reception patterns are known. The reception patterns do not have to be orthogonal or even linearly independent. It is shown that the operation of phased arrays is intimately related to the mathematical theory of frames, and that the theory of frames can be used to determine the degree to which any class of intensity or field distribution can be reconstructed unambiguously from the complex amplitudes of the travelling waves at the output ports. The theory can be used to set up a likelihood function that can, through Fisher information, be used to determine the degree to which a phased array can be used to recover the parameters of a parameterised source. For example, it would be possible to explore the way in which a system, perhaps interferometric, might observe two widely separated regions of the sky simultaneously

Transforming Training in Orientation and Mobility: Examining the Effect Using an Audio-Link on the Distance Between Trainer and Trainee

Increased distances between instructor and trainee during orientation and mobility (O&M) training is purported to be associated with improved outcomes of heightened independence, self-efficacy, and preparation for real-world experience as a traveller. However, there is currently no research that identifies standard or optimal instructor-trainee distances or effoctive strategies to increase distances that enhance training outcomes. This exploratory, qualitative study compared the distance between two instructor-trainee dyads over ten 1.5-hour lessons. The first jive lessons were conducted without an Audio-link device, and the second jive occurred using the device. Results indicated that use of an Audio-link system significantly increased training distances between teacher/student dyads beyond proximities measured without the device. The implications for training and research are discussed

Oral Examination

The oral cavity is the first component of the digestive tract, which is delimited by the lips anteriorly and the oropharynx posteriorly. The oral cavity functions as a protective barrier and is an essential component for speech and swallowing, mastication, digestion, and taste sensation. The oral examination comprises a uniform and consistent inspection of the head and neck and an intraoral evaluation of the hard and soft tissues (see the images below) in conjunction with a thorough medical and dental history. The entire mouth should be inspected regardless of the patient’s chief complaint and reasons for the visit. [1, 2] Good patient’s history and careful examination are important to establish the correct diagnosis and provide appropriate treatment. The physical examination begins with an extraoral examination to identify possible lesions (such as rash, erythema, and pigmentation), swelling or facial asymmetry. The head and neck should be palpated to identify any tenderness, masses and lymphadenopathy. All muscles of mastication and temporomandibular joint should be palpated for tenderness; patients should be asked to open and close the mouth multiple times to evaluate any limited opening, deviations or asymmetries. The cranial nerve examination should be performed to assess possible neurosensory and neuromuscular deficits. A good light source is fundamental for a good intraoral examination. Any intraoral lesion should be described with respect to size, extent, thickness, color, texture, consistency, and tenderness

A review of the characteristics and treatment progress of 45 pregnant opiate addicts attending the Irish National Drug Advisory and Treatment Centre over a two year period.

The increase in the number of patients presenting to the National Drug Advisory and Treatment Centre addicted to opiates has been accompanied by an increase in the number of pregnant opiate addicts attending for treatment. Studies published in January 1982 referred to the emergence of maternal addiction as a serious problem in Ireland. Since then the escalation of this specific problem has continued and a programme designed to meet the needs of the pregnant addict was initiated at the clinic. This paper reviews the characteristics and treatment progress of 45 opiate addicts who were referred to the clinic over a two year period

What Matters Most? The Perceived Importance of Ability and Personality for Hiring Decisions

This study examined the emphasis hiring managers placed on general mental ability (GMA) and personality—agreeableness, conscientiousness, emotional stability, and extraversion—when evaluating applicant profiles for servers for a national restaurant chain. GMA was framed as either “intelligence” or the “ability to learn and solve problems.” Under both conditions, GMA was valued, but less than agreeableness, conscientiousness, and emotional stability, even though GMA has been demonstrated to be the strongest predictor of employee performance. Framed as the “ability to learn and solve problems,” GMA was more highly valued, but still less than personality

Long-term spatial heterogeneity in mallard distribution in the Prairie pothole region

The Prairie Pothole Region (PPR) of north-central United States and south-central Canada supports greater than half of all breeding mallards (Anas platyrhynchos) annually counted in North America and is the focus of widespread conservation and research efforts. Allocation of conservation resources for this socioeconomically important population would benefit from an understanding of the nature of spatiotemporal variation in distribution of breeding mallards throughout the 850,000 km2 landscape. We used mallard counts from the Waterfowl Breeding Population and Habitat Survey to test for spatial heterogeneity and identify high- and low-abundance regions of breeding mallards over a 50-year time series. We found strong annual spatial heterogeneity in all years: 90% of mallards counted annually were on an average of only 15% of surveyed segments. Using a local indicator of spatial autocorrelation, we found a relatively static distribution of low-count clusters in northern Montana, USA, and southern Alberta, Canada, and a dynamic distribution of high-count clusters throughout the study period. Distribution of high-count clusters shifted southeast from northwestern portions of the PPR in Alberta and western Saskatchewan, Canada, to North and South Dakota, USA, during the latter half of the study period. This spatial redistribution of core mallard breeding populations was likely driven by interactions between environmental variation that created favorable hydrological conditions for wetlands in the eastern PPR and dynamic land-use patterns related to upland cropping practices and government land-retirement programs. Our results highlight an opportunity for prioritizing relatively small regions within the PPR for allocation of wetland and grassland conservation for mallard populations. However, the extensive spatial heterogeneity in core distributions over our study period suggests such spatial prioritization will have to overcome challenges presented by dynamic land-use and climate patterns in the region, and thus merits additional monitoring and empirical research to anticipate future population distribution. Published 2017. This article is a U.S. Government work and is in the public domain in the USA

A guide to photocuring catalyst selection

The utilization of light as an energy source to convert liquid resins (termed photopolymers) into solid plastics is a burgeoning field in polymer science. Photopolymerizations have found broad applications in imaging and curing technologies (e.g. photoresists, photolithography, and photocurable coatings) and the driving of rapid polymerizations with visible to near-infrared light will enable nascent technologies in the emerging fields of bio- and composite-3D printing. However, current photopolymerization strategies are limited by long reaction times, high light intensities, and/or large catalyst loadings. The improvement of efficiency remains elusive without a comprehensive, mechanistic evaluation of photocatalysis to better understand how composition relates to polymerization metrics. With this objective in mind, a series of BODIPYs, azaBODIPYs, thiopheneBODIPYs and thionaphthalimides were synthesized and systematically characterized to elucidate key structure–property relationships that correlate to efficient photopolymerization driven by visible to near-IR light. For all these scaffolds, access to longer lived photoexcited states was shown as a general method to increase polymerization rate, quantitatively characterized using a custom real-time infrared spectroscopy setup. Furthermore, a combination of steady-state emission quenching experiments, electronic structure calculations, and ultrafast transient absorption revealed that efficient intersystem crossing to the lowest excited triplet state was a key mechanistic step to achieving rapid photopolymerization reactions. Unprecedented polymerization rates were achieved with extremely low light intensities (<1 mW/cm²) and catalyst loadings (<50 μM), exemplified by reaction completion within 60 s of irradiation using green, red, far-red, and near-IR light-emitting diodes. The photoredox catalysts were additionally employed to produce complex 3D structures using high-resolution visible light and near-IR 3D printing, demonstrating the broad utility of these catalysts in additive manufacturing.Chemistr