Skylab program payload integration. TO27 sample array

The objective of the TO27 sample array was to determine the change in optical properties of various transmissive windows, mirrors, and diffraction gratings caused by the deposition of contaminants found about the orbital assembly. The expected information to be obtained from the total TO27 sample array program is as follows: (1) effect of space contaminants on transmittance, reflectance, grating efficiency, and polarization; (2) variations in deposition of contaminants due to substrate, solar radiation, period of exposure, direction of exposure, and geometry effects; (3) identification of contaminants and source of evolution; (4) time of contaminant evolution and lingering time; and (5) guidelines for a model of spacecraft contamination

On the Wilf-Stanley limit of 4231-avoiding permutations and a conjecture of Arratia

We construct a sequence of finite automata that accept subclasses of the class of 4231-avoiding permutations. We thereby show that the Wilf-Stanley limit for the class of 4231-avoiding permutations is bounded below by 9.35. This bound shows that this class has the largest such limit among all classes of permutations avoiding a single permutation of length 4 and refutes the conjecture that the Wilf-Stanley limit of a class of permutations avoiding a single permutation of length k cannot exceed (k-1)^2.Comment: Submitted to Advances in Applied Mathematic

Modelling the costs and benefits of hybrid buses from a whole-life perspective

Hybrid electric-diesel engine technologies offer the potential to reduce fuel consumption in buses by around 40%. These savings can largely be attributed to regenerative braking – the ability to store in a battery energy that would otherwise have been lost under braking. Lower fuel consumption makes sense economically for bus operators through reduced running costs; hybrid engines have other wider benefits, though, such as reducing emissions and noise, and providing smoother acceleration and braking. The costs associated with hybrid technologies are significant, however, with hybrid vehicles currently costing around 50% more to buy than conventional buses. With Alexander Dennis and BAE Systems, UCL is conducting a three-year systems engineering research and development project to adapt and optimise hybrid buses for the UK and European market. This paper investigates one aspect of this project – the costs and benefits of introducing hybrid bus technologies from a whole-life perspective. We find that fuel and emissions savings alone do not provide a compelling case for hybrid buses based on current prices. However, as the cost of fuel rises, and when the social and environmental impacts of motor vehicle use are better accounted for, hybrid technology outperforms conventional diesel technology

Genetic solutions through breeding counteract climate change and secure barley production in Australia

Climate changes threaten global sustainable food supply by reducing crop yield. Estimates of future crop production under climate change have rarely considered the capacity of genetic improvement in breeding high-yielding and stress-tolerant crop varieties. We believe that technological advancements and developing climate-resilient crop varieties may offset the adverse effects of climate change. In this study, we examined the historical record of barley breeding and yield, and the trends of climate changes over the past 70 years in Australia. We related the selection of fast development varieties to yield improvement, and revealed the genetic connections of fast development and yield potential through genome-wide association studies. Historical records show that Australia's barley yield has experienced a steady growth despite that the seasonal production window has been shortened due to increased risk of frost damage at flowering stage and terminal heat during maturity since the 1970s. The increase in yield is largely the result of higher yield capacity of the more recently developed varieties that develop faster to counteract the impact of increased terminal heat. We also show that the changing temperature may soon reach a critical point that dramatically changes the barley flowering behaviour to impact yield by pushing its growth beyond the seasonal production window to face increasing frost damage. For the first time, we provide evidence that the effects of climate change on crop production might be less severe than what is currently believed because the advancement of technologies and development of climate-resilient crop varieties may mitigate the adverse effect of climate change to some extent. The greater use of genetic techniques in crop breeding will play a vital role in sustainable global food production in the era of climate change

Chronic Obstructive Pulmonary Disease: Thoracic CT Texture Analysis and Machine Learning to Predict Pulmonary Ventilation

Background Fixed airflow limitation and ventilation heterogeneity are common in chronic obstructive pulmonary disease (COPD). Conventional noncontrast CT provides airway and parenchymal measurements but cannot be used to directly determine lung function. Purpose To develop, train, and test a CT texture analysis and machine-learning algorithm to predict lung ventilation heterogeneity in participants with COPD. Materials and Methods In this prospective study

Some results and problems for anisotropic random walks on the plane

This is an expository paper on the asymptotic results concerning path behaviour of the anisotropic random walk on the two-dimensional square lattice Z^2. In recent years Mikl\'os and the authors of the present paper investigated the properties of this random walk concerning strong approximations, local times and range. We give a survey of these results together with some further problems.Comment: 20 page

Prospective comparison of long-term pain relief rates after first-time microvascular decompression and stereotactic radiosurgery for trigeminal neuralgia

OBJECTIVE Common surgical treatments for trigeminal neuralgia (TN) include microvascular decompression (MVD), stereotactic radiosurgery (SRS), and radiofrequency ablation (RFA). Although the efficacy of each procedure has been described, few studies have directly compared these treatment modalities on pain control for TN. Using a large prospective longitudinal database, the authors aimed to 1) directly compare long-term pain control rates for first-time surgical treatments for idiopathic TN, and 2) identify predictors of pain control. METHODS The authors reviewed a prospectively collected database for all patients who underwent treatment for TN between 1997 and 2014 at the University of California, San Francisco. Standardized collection of data on preoperative clinical characteristics, surgical procedure, and postoperative outcomes was performed. Data analyses were limited to those patients who received a first-time procedure for treatment of idiopathic TN with > 1 year of follow-up. RESULTS Of 764 surgical procedures performed at the University of California, San Francisco, for TN (364 SRS, 316 MVD, and 84 RFA), 340 patients underwent first-time treatment for idiopathic TN (164 MVD, 168 SRS, and 8 RFA) and had > 1 year of follow-up. The analysis was restricted to patients who underwent MVD or SRS. Patients who received MVD were younger than those who underwent SRS (median age 63 vs 72 years, respectively; p 5 years of follow-up (60 of 164 and 64 of 168 patients, respectively). Immediate or short-term (< 3 months) postoperative pain-free rates (Barrow Neurological Institute Pain Intensity score of I) were 96% for MVD and 75% for SRS. Percentages of patients with Barrow Neurological Institute Pain Intensity score of I at 1, 5, and 10 years after MVD were 83%, 61%, and 44%, and the corresponding percentages after SRS were 71%, 47%, and 27%, respectively. The median time to pain recurrence was 94 months (25th–75th quartiles: 57–131 months) for MVD and 53 months (25th–75th quartiles: 37–69 months) for SRS (p = 0.006). A subset of patients who had MVD also underwent partial sensory rhizotomy, usually in the setting of insignificant vascular compression. Compared with MVD alone, those who underwent MVD plus partial sensory rhizotomy had shorter pain-free intervals (median 45 months vs no median reached; p = 0.022). Multivariable regression demonstrated that shorter preoperative symptom duration (HR 1.005, 95% CI 1.001–1.008; p = 0.006) was associated with favorable outcome for MVD and that post-SRS sensory changes (HR 0.392, 95% CI 0.213–0.723; p = 0.003) were associated with favorable outcome for SRS. CONCLUSIONS In this longitudinal study, patients who received MVD had longer pain-free intervals compared with those who underwent SRS. For patients who received SRS, postoperative sensory change was predictive of favorable outcome. However, surgical decision making depends upon many factors. This information can help physicians counsel patients with idiopathic TN on treatment selection

Employability and higher education: contextualising female students' workplace experiences to enhance understanding of employability development

Current political and economic discourses position employability as a responsibility of higher education, which deploys mechanisms such as supervised work experience (SWE) to embed employability skills development into the undergraduate curriculum. However, workplaces are socially constructed complex arenas of embodied knowledge that are gendered. Understanding the usefulness of SWE therefore requires consideration of the contextualised experiences of it, within these complex environments. This study considers higher education's use of SWE as a mechanism of employability skills development through exploration of female students' experiences of accounting SWE, and its subsequent shaping of their views of employment. Findings suggest that women experience numerous, indirect gender-based inequalities within their accounting SWE about which higher education is silent, perpetuating the framing of employability as a set of individual skills and abilities. This may limit the potential of SWE to provide equality of employability development. The study concludes by briefly considering how insights provided by this research could better inform higher education's engagement with SWE within the employability discourse, and contribute to equality of employability development opportunity

Pulmonary Imaging Phenotypes of Chronic Obstructive Pulmonary Disease Using Multiparametric Response Maps

Background Pulmonary imaging of chronic obstructive pulmonary disease (COPD) has focused on CT or MRI measurements, but these have not been evaluated in combination. Purpose To generate multiparametric response map (mPRM) measurements in ex-smokers with or without COPD by using volume-matched CT and hyperpolarized helium 3

Aqueous peptide-TiO2 interfaces: iso-energetic binding via either entropically- or enthalpically-driven mechanisms

A major barrier to the systematic improvement of biomimetic peptide-mediated strategies for the controlled growth of inorganic nanomaterials in environmentally benign conditions lies in the lack of clear conceptual connections between the sequence of the peptide and its surface binding affinity, with binding being facilitated by non-covalent interactions. Peptide conformation, both in the adsorbed and non-adsorbed state, is the key relationship that connects peptide-materials binding with peptide sequence. Here, we combine experimental peptide–titania binding characterization with state-of-the-art conformational sampling via molecular simulations to elucidate these structure/binding relationships for two very different titania-binding peptide sequences. The two sequences (Ti-1: QPYLFATDSLIK and Ti-2: GHTHYHAVRTQT) differ in their overall hydropathy, yet via quartz-crystal microbalance measurements and predictions from molecular simulations, we show these sequences both support very similar, strong titania-binding affinities. Our molecular simulations reveal that the two sequences exhibit profoundly different modes of surface binding, with Ti-1 acting as an entropically-driven binder while Ti-2 behaves as an enthalpically-driven binder. The integrated approach presented here provides a rational basis for peptide sequence engineering to achieve the in-situ growth and organization of titania nanostructures in aqueous media and for the design of sequences suitable for a range of technological applications that involve the interface between titania and biomolecules