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Relative to their typically developing peers, autistic individuals experience greater difficulties in domains of functioning that are relevant to learning and adult outcomes, such as sensory sensitivities, anxiety, and social. However, little is known about how difficulties in these domains relate to the receipt of special education services as well as adult outcomes, such as vocational achievement. The current study sought to fill this gap by examining if difficulties in various learning-related domains as ascertained via the Learning Needs Screening Tool (LNST) were associated with historical special education receipt and vocational status.
Participants and Methods:
400 autistic adults, recruited via the Simons Powering Autism Research (SPARK) participant registry Research Match service, participated in this study (40.5% male, mean age=28.9 years). All participants completed the LNST, which collects responses to 13 core questions about learning (such as challenges with memorization, note taking, spelling and identifying arithmetic signs), as well as 7 additional questions with checkbox and free response options, and yields a total score from 0-30. LNST item 14 and its response options (1-9) capture suspected causes of learning difficulties (e.g., 'too much noise or activity bothers me,' 'I get nervous taking tests'). These individual questions as well as the total of endorsed learning related challenges were then evaluated in relation to historical special education receipt (“yes” vs. “no”) and vocational outcomes (“yes” vs. “no” engaging in 10+ hours of postsecondary education or employment without supports), as assessed via the Taylor Vocational Index.
Results:
Logistic regression was utilized to predict the dependent variables of interest. Models included sex assigned at birth and age in the first step as covariates. Then either the total of learning related challenges endorsed or the 9 individual learning-related challenges from the LNST were included as independent variables of interest. For historical special education receipt, two items - “It’s hard for me to work by myself” (B = .78, p<.05) and “I get nervous taking tests” (B = .49, p<.05) were positively associated with a history of special education services. For vocational outcomes, the total learning related challenges (B = -.25, p<.001) as well as endorsement of one item -“It’s hard for me to work by myself” (B = -.88, p=<.05) were associated with poorer vocational outcomes.
Conclusions:
These findings shed light on the possible learning-related challenges that are experienced by autistic adults. Further examination of the role these learning related challenges play in the receipt of special education and on vocational outcomes is warranted. In particular, difficulties with independence in work was related to both special education receipt and poorer vocational outcomes, indicating that it may be a fruitful area of focus for vocational training programs.
Retropharyngeal haematomas are most commonly associated with trauma and anti-coagulant use. This paper describes the first reported case of a spontaneous retropharyngeal haematoma suspected to be due to indomethacin use.
Case report
It is proposed that the combination of indomethacin affecting platelet aggregation, alongside the patient coughing, may have led to this retropharyngeal haematoma.
Conclusion
The complexities of management are discussed and the current literature reviewed. In the absence of airway compromise or a rapidly enlarging haematoma, patients can be managed conservatively with observation and close discussion with the haematology department. Follow-up imaging is not necessary if the patient's symptoms settle; however, any increase in parathyroid hormone levels must be investigated to exclude a parathyroid adenoma.
This book is an introduction, for mathematics students, to the theories of information and codes. They are usually treated separately but, as both address the problem of communication through noisy channels (albeit from different directions), the authors have been able to exploit the connection to give a reasonably self-contained treatment, relating the probabilistic and algebraic viewpoints. The style is discursive and, as befits the subject, plenty of examples and exercises are provided. Some examples and exercises are provided. Some examples of computer codes are given to provide concrete illustrations of abstract ideas.
Introduction: Patients with advanced malignant and non-malignant disease (advanced disease—AD) who do not want or benefit from aggressive resuscitation may unfortunately receive such treatments if unable to communicate in an emergency. Timely access to patients’ resuscitation wishes is imperative for treating physicians and for medical information systems. Our aim was to determine what proportion of emergency department (ED) patients with AD have accurate, readily accessible resuscitation status documentation. Methods: This cross-sectional, prospective study was conducted at a tertiary care ED during purposefully sampled random accrual times in summer 2016. We enrolled all patients with: 1) palliative care consultation, 2) metastatic malignancy, 3) COPD or CHF on home oxygen, 4) hemodialysis, or 5) advanced neurodegenerative disease/dementia. The primary outcome was the retrieval of any existing resuscitation status documents. Documentation was obtained from a standardized review of forms accompanying the patient (“arrival documents”) and electronic medical record (“EMR”). We measured the time to retrieve this documentation, and interviewed consenting patients to corroborate documentation with their current wishes. Results: Of 85 enrolled patients, only 33 (39%) had any documentation of resuscitation status: 28 (33%) had goals of care retrieved from the hospital EMR, and 11 (15%) from arrival documents (some had both). Patients from long-term care facilities were more likely to have documentation available (odds ratio 13 [95% CI 2.5-65] vs community-living). Of 32 patients who were able to be interviewed, 20 (63%) expressed “do not resuscitate” wishes. Ten of these 20 lacked any documents to support their expressed resuscitation wishes. Previously expressed resuscitation wishes took more than 5 minutes to be retrieved in 3 cases when not filed “one click deep” in our EMR. Conclusion: The majority of patients with AD, including half of those who would not wish resuscitation from cardiorespiratory arrest, did not have goals of care documents readily available upon arrival to the ED. Patients living in the community with AD appear to be at high risk for unwanted resuscitative treatments should they present to hospital in extremis. Having documentation of their goals of care that is easily retrievable from the EMR shows promise, though issues of retrieval, accuracy, and validity remain important considerations.
The importance of Meganyctiphanes norvegica (M. Sars) as a source of vitamin A for its predators has been demonstrated by Fisher, Kon & Thompson (1955). Basing their conclusions on the observations of Macdonald (1927) on the feeding of M. norvegica in Loch Fyne, Fisher, Kon & Thompson (1954) and Kon (1954) suggested a possible scheme of accumulation of vitamin A in the animal. They also made cursory examinations of the stomach contents from animals caught in the same area and their findings appeared to agree fairly well with those of Macdonald, except that from his results he concluded that phytoplankton was a major item in the diet. This conclusion has been disputed by Einarsson (1945) who called for more detailed investigation of fresh material in order to obtain a clearer picture of the feeding of north Atlantic euphausiids. Such information would be of great value in the study of the vitamin A chain in the plankton. We have, therefore, examined the stomach contents of M. norvegica over nearly two years to try to detect every type of food that might be eaten. In addition to our own survey, Dr J. Mauchline (1959) of the Marine Station, Millport, made a more intensive study of the food in relation to the diurnal migrations in July and November.
The ClOVER instrument (described elsewhere in this volume) isbeing built to measure the B-mode polarisation of the Cosmic MicrowaveBackground. Each of the 256 pixels is made up a pseudo-correlationreceiver that can be realised using either waveguide or microstriptechnology. In this work we present a design study for a possiblewaveguide-based solution. Each of the individual components has beenoptimised using electromagnetic finite-element modelling software(HFSS).
We present a new, fully-funded ground-based instrument designed to measurethe B-mode polarization of the Cosmic Microwave Background (CMB). The conceptis based on three independent sub-systems operating at 90, 150 and 220 GHz,each comprising a telescope and a focal plane of horn-coupled background-limited bolometers. This highly-sensitive experiment, planned to be based at Dome C station in Antarctica, is optimised to produce very low systematiceffects. It will allow the detection of the CMB polarization over angular multipoles 20<l<1000accurately enough to measure the B-mode signature from gravitationalwaves to a lensing-confusion-limited tensor-to-scalar ratio r ~ 0.005.
Moderately and heavily Mg-doped GaN were studied by a combination of post-growth annealing processes and electron beam irradiation techniques during cathodoluminescence (CL) to elucidate the chemical origin of the recombination centers responsible for the main optical emission lines. The shallow donor at 20–30 meV below the conduction band, which is involved in the donor-acceptor-pair (DAP) emission at 3.27 eV, was attributed to a hydrogen-related center, presumably a (VN-H) complex. Due to the small dissociation energy (<2 eV) of the (VN-H) complex, this emission line was strongly reduced by low-energy electron irradiation. CL investigations of the DAP at a similar energetic position in Si-doped (n-type) GaN indicated that this emission line is of different chemical origin than the 3.27 eV DAP in Mg-doped GaN. A slightly deeper DAP emission centered at 3.14 eV was observed following low-energy electron irradiation, indicating the appearance of an additional donor level with a binding energy of 100–200 meV, which was tentatively attributed to a VN-related center. The blue band (2.8–3.0 eV) in heavily Mg-doped GaN was found to consist of at least two different deep donor levels at 350±30 meV and 440±40 meV. The donor level at 350±30 meV was strongly affected by electron irradiation and attributed to a H-related defect.
Molecular beam epitaxy-grown GaN with different Mn concentrations (5–23 × 10 cm-3) and codoped with Si were investigated by cathodoluminescence (CL) spectroscopy and optical transmission measurements. In the GaN:Mn, an intense absorption peak at 1.414 +/- 0.002 eV was observed. This peak was attributed to an internal T2∼> E transition of the deep neutral Mn3+ state since its intensity scaled with the Mn3+ concentration. The CL measurements showed that Mn-doping concentrations around 1020 cm-3 had three effects on the emission spectrum: (i) the donor bound exciton at 3.460 eV was reduced by more than one order of magnitude, (ii) the donor-acceptor-pair band at 3.27 eV was completely quenched and (iii) the yellow luminescence centered at 2.2 eV was the strongly decreased. The latter two effects were attributed to a reduced concentration of VGa. In the infrared spectral range, three broad, Mn-doping related CL emission bands centered at 1.01 ± 0.02 eV, 1.09 ± 0.02 eV and 1.25 ± 0.03 eV were observed. These bands might be related to deep donor complexes, which are generated as a result of the heavy Mn-doping, rather than internal transitions at the Mn atom.
CL spectroscopy studies at varying temperatures and excitation power densities as well as depth-resolved CL imaging were conducted to investigate the impact of low energy electron beam irradiation (LEEBI) on native defects and residual impurities in metal-organic vapor phase epitaxy (MOVPE) grown Mg-doped p-type GaN. Due to the dissociation of (Mg-H)0 complexes, LEEBI significantly increases the (e,Mg0) emission (3.26 eV) at 300 K and substantially decreases the H-Mg donor-acceptor-pair (DAP) emission (3.27 eV) at 80 K. In-plane and depth-resolved CL imaging indicates that hydrogen dissociation results from electron-hole recombination at H-defect complexes rather than heating by the electron beam. The dissociated hydrogen atoms associate with nitrogen vacancies, forming a deeper donor, i.e. a (H-VN) complex. The corresponding deeper DAP emission with Mg centered at 3.1 eV is clearly observed between 160 and 220 K. Moreover, a broad yellow luminescence (YL) band centered at 2.2 eV is observed in MOVPE-grown Mg-doped GaN after LEEBI-treatment. It is suggested that a combination of LEEBI-induced Fermi-level downshift due to Mg-acceptor activation and simultaneous dissociation of gallium vacancy-impurity complexes, i.e. (VGa-H), is responsible for the observed YL.
Raman scattering (RS) spectroscopy is employed to characterize the effect of nitrogen on structural properties of GaNxP1-x alloy with nitrogen composition up to 3 %. Two-mode behavior of the alloy is clearly shown. The frequency of the GaP-like LO phonons is found to decrease with N composition as –1.13 cm-1x. This dependence is proposed to be largely due to the biaxial strain in the GaNP epilayers, as a result of lattice mismatch to the GaP substrate. The frequency of the GaN-like phonons is found to be more sensitive to nitrogen content, increasing with the rate of +2.6 cm-1x. The addition of nitrogen is also found to cause a dramatic quenching of the two-phonon Raman scattering and an appearance of the zone edge GaP-like vibrations. These effects are suggested to reflect local distortion in the GaNP lattice induced by nitrogen, as well as possible clustering of N atoms.
In this paper we evaluate the in-depth homogeneity of GaN epilayers and the influence of electric field present in strained GaN/AlGaN heterostructures and quantum wells on the yellow and “edge” emission in GaN and AlGaN. Our depth-profiling cathodoluminescence measurements show an increased accumulation of defects at the interface. Inhomogeneities in the doping level are reflected by the enhancement of the yellow emission in the interface region. The piezoelectric effect is found to strongly reduce the emission from the strained AlGaN quantum-well barriers. We also show that Ga droplets, commonly found on surfaces of samples grown in Ga-rich conditions, screen the internal electric field in a structure and thus result in a local enhancement of the edge emission intensity.
We have shown that Zr-based metallization can effectively remove hydrogen from the p-type GaN subsurface, which eventually leads to the formation of an ohmic contact. As the release of hydrogen starts at ∼900°C, the thermal stability of the contact system is of particular importance. The remarkable thermal behavior of the ZrN/ZrB2 metallization is associated to the microstructure of each individual Zr-based compound, as well as to the interfacial crystalline accommodation.
Metalorganic chemical vapor deposition (MOCVD) GaSb growth using trimethylgallium and trimethylantimony as a function of substrate temperature and V/III ratio was examined. These parameters were found to have a significant effect on the growth rate and surface morphology of the GaSb films. A phase diagram is used to interpret the effect of these growth parameters on the GaSb film growth. The region of single-phase growth was found to be narrow, falling between 540 and 560 °C. The optimum growth conditions for the MOCVD growth of GaSb have been determined for a TMGa flow rate of 20 sccm and a carrier gas flow of 8 l/min. The optimum substrate temperature and V/III ratio were found to be 540 °C and 0.72, respectively. In these conditions the lowest hole concentration of 5 × 1016 cm-3 and the highest room temperature mobility of 500 cm2 V-1 s-1 were achieved, accompanied by a steep, well-resolved band edge at 0.72 eV.
We have shown that Zr-based metallization can effectively remove hydrogen from the p-type GaN subsurface, which eventually leads to the formation of an ohmic contact. As the release of hydrogen starts at ∼900°C, the thermal stability of the contact system is of particular importance. The remarkable thermal behavior of the ZrN/ZrB2 metallization is associated to the microstructure of each individual Zr-based compound, as well as to the interfacial crystalline accommodation.
Optical properties of GaN epilayers of a cubic phase are studied. We show a strong influence of the sample morphology on intensity of the edge emission. Whereas edge luminescence is reduced at the grain boundaries, red emission is spatially homogeneous.
Traditionally, control algorithms for Terfenol-D® magnetostrictive actuators have modelled the strain as a linear function of magnetic field and stress, but nonlinearity becomes important for strains of more than a few hundred parts per million (ppm), and for many applications even the maximum strain, about 1500 ppm, is inadequate. Larger strokes can be obtained by various types of stroke amplifiers, by resonant operation, or by inchworming. Previously, SatCon successfully used a 10:1 lever arm stroke amplifier in a helicopter flap actuator [1]. Current projects include a water pump using a hydraulic stroke amplifier, which potentially could be more compact and efficient than a lever arm amplifier, and linear and rotary inchworm motors for robotics. In all these designs, satisfactory performance requires careful attention to machining tolerances and to making the mechanisms and housing stiff enough or compliant enough. A model for inchworm motors has been developed, including finite load and resonant effects. Nonlinear control algorithms will be discussed, applicable to arbitrarily large Terfenol-D® strains, stresses, and magnetic fields.
This text is based on a course of the same title given at Cambridge for a number of years. It consists of an introduction to information theory and to coding theory at a level appropriate to mathematics undergraduates in their second or later years. Prerequisites needed are a knowledge of discrete probability theory and no more than an acquaintance with continuous probability distributions (including the normal). What is needed in finite-field theory is developed in the course of the text, but some knowledge of group theory and vector spaces is taken for granted.
The two topics treated are traditionally put into mathematical pigeon-holes remote from each other. They do however fit well together in a course, in addressing from different standpoints the same problem, that of communication through noisy channels. The authors hope that undergraduates who have liked algebra courses, or probability courses, will enjoy the otherhalf of the book also, and will feel at the end that their knowledge of how it all fits together is greater than the sum of its parts.
The Cambridge course was invented by Peter Whittle and the debt that particularly the information-theoretic part of the book owes him is unrepayable. Certain features that distinguish the present approach from that found elsewhere are due to him, in particular the conceptual ‘decoupling’ of source and channel, and the definition of channel capacity as a maximized rate of reliable transmission. The usual definition of channel capacity is, from that standpoint, an evaluation,less fundamental than the definition.
In detail, the first four chapters cover the information-theory part of the course. The first, on noiseless coding, also introduces entropy, for use throughout the text. Chapter 2 deals with information sources and gives a careful treatment of the evaluation of rate of information output. Chapters 3 and 4 deal with channels and random coding. An initial approach to the evaluation of channel capacity is taken in Chapter 3 that is not quite sharp, and so yields only bounds, but which seems considerably more direct and illuminating than the usual approach through mutual information. The latter route is taken in Chapter 4, where several channel capacities are exactly calculated.