20 research outputs found

    Development and inflight validation of an automated flight planning system using multiple-sensor windfield estimation

    Get PDF
    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1993.Includes bibliographical references (leaves 78-79).by Andrew Kevin Barrows.M.S

    Multilayer broadband anti-reflective coatings for bulk heterojunction polymer solar cells

    Get PDF
    The photocurrent produced by solar cells is limited by reflection losses for all types of photovoltaic devices. The first reflection loss occurs at the glass/air interface of the photovoltaic device. A solar cell without a light trapping mechanism in place loses around 4 % of the solar energy at this interface. To minimise the losses, a broadband multilayer thin film anti-reflection (MAR) coating has been designed and deposited onto the glass surface of a solar cell. The coating consisted of four dielectric layers of alternating thin films of ZrO2 and SiO2. The layers were deposited by using high rate pulsed DC magnetron sputtering using time only for nanometre thickness control. Spectrophotometer measurements confirm that the transmission increased over the spectrum utilized by the bulk heterojunction (BHJ) solar cell (350nm- 700nm). The weighted average reflection reduced from 4.22% to 0.99%. BHJ solar cells with a PCDTBT:PCBM blend serving as the active layer were prepared on a MAR coated soda lime glass slides to verify the effectiveness of the coating. The efficiency increased by 0.18% at STC from 4.98% to 5.17% (a 3.7% relative increase). The gain was achieved by increasing the photocurrent from 11.96 mA/cm2 to 12.36 mA/cm2

    A population of luminous accreting black holes with hidden mergers

    Full text link
    Major galaxy mergers are thought to play an important part in fuelling the growth of supermassive black holes. However, observational support for this hypothesis is mixed, with some studies showing a correlation between merging galaxies and luminous quasars and others showing no such association. Recent observations have shown that a black hole is likely to become heavily obscured behind merger-driven gas and dust, even in the early stages of the merger, when the galaxies are well separated (5 to 40 kiloparsecs). Merger simulations further suggest that such obscuration and black-hole accretion peaks in the final merger stage, when the two galactic nuclei are closely separated (less than 3 kiloparsecs). Resolving this final stage requires a combination of high-spatial-resolution infrared imaging and high-sensitivity hard-X-ray observations to detect highly obscured sources. However, large numbers of obscured luminous accreting supermassive black holes have been recently detected nearby (distances below 250 megaparsecs) in X-ray observations. Here we report high-resolution infrared observations of hard-X-ray-selected black holes and the discovery of obscured nuclear mergers, the parent populations of supermassive-black-hole mergers. We find that obscured luminous black holes (bolometric luminosity higher than 2x10^44 ergs per second) show a significant (P<0.001) excess of late-stage nuclear mergers (17.6 per cent) compared to a sample of inactive galaxies with matching stellar masses and star formation rates (1.1 per cent), in agreement with theoretical predictions. Using hydrodynamic simulations, we confirm that the excess of nuclear mergers is indeed strongest for gas-rich major-merger hosts of obscured luminous black holes in this final stage.Comment: To appear in the 8 November 2018 issue of Nature. This is the authors' version of the wor

    Smoke, curtains and mirrors: the production of race through time and title registration

    Get PDF
    This article analyses the temporal effects of title registration and their relationship to race. It traces the move away from the retrospection of pre-registry common law conveyancing and toward the dynamic, future-oriented Torrens title registration system. The Torrens system, developed in early colonial Australia, enabled the production of ‘clean’, fresh titles that were independent of their predecessors. Through a process praised by legal commentators for ‘curing’ titles of their pasts, this system produces indefeasible titles behind its distinctive ‘curtain’ and ‘mirror’, which function similarly to magicians’ smoke and mirrors by blocking particular realities from view. In the case of title registries, those realities are particular histories of and relationships with land, which will not be protected by property law and are thus made precarious. Building on interdisciplinary work which theorises time as a social tool, I argue that Torrens title registration produces a temporal order which enables land market coordination by rendering some relationships with land temporary and making others indefeasible. This ordering of relationships with land in turn has consequences for the human subjects who have those relationships, cutting futures short for some and guaranteeing permanence to others. Engaging with Renisa Mawani and other critical race theorists, I argue that the categories produced by Torrens title registration systems materialise as race

    The impact of immediate breast reconstruction on the time to delivery of adjuvant therapy: the iBRA-2 study

    Get PDF
    Background: Immediate breast reconstruction (IBR) is routinely offered to improve quality-of-life for women requiring mastectomy, but there are concerns that more complex surgery may delay adjuvant oncological treatments and compromise long-term outcomes. High-quality evidence is lacking. The iBRA-2 study aimed to investigate the impact of IBR on time to adjuvant therapy. Methods: Consecutive women undergoing mastectomy ± IBR for breast cancer July–December, 2016 were included. Patient demographics, operative, oncological and complication data were collected. Time from last definitive cancer surgery to first adjuvant treatment for patients undergoing mastectomy ± IBR were compared and risk factors associated with delays explored. Results: A total of 2540 patients were recruited from 76 centres; 1008 (39.7%) underwent IBR (implant-only [n = 675, 26.6%]; pedicled flaps [n = 105,4.1%] and free-flaps [n = 228, 8.9%]). Complications requiring re-admission or re-operation were significantly more common in patients undergoing IBR than those receiving mastectomy. Adjuvant chemotherapy or radiotherapy was required by 1235 (48.6%) patients. No clinically significant differences were seen in time to adjuvant therapy between patient groups but major complications irrespective of surgery received were significantly associated with treatment delays. Conclusions: IBR does not result in clinically significant delays to adjuvant therapy, but post-operative complications are associated with treatment delays. Strategies to minimise complications, including careful patient selection, are required to improve outcomes for patients

    The BraveNet prospective observational study on integrative medicine treatment approaches for pain

    Get PDF
    BACKGROUND: Chronic pain affects nearly 116 million American adults at an estimated cost of up to $635 billion annually and is the No. 1 condition for which patients seek care at integrative medicine clinics. In our Study on Integrative Medicine Treatment Approaches for Pain (SIMTAP), we observed the impact of an integrative approach on chronic pain and a number of other related patient-reported outcome measures. METHODS: Our prospective, non-randomized, open-label observational evaluation was conducted over six months, at nine clinical sites. Participants received a non-standardized, personalized, multimodal approach to chronic pain. Validated instruments for pain (severity and interference levels), quality of life, mood, stress, sleep, fatigue, sense of control, overall well-being, and work productivity were completed at baseline and at six, 12, and 24 weeks. Blood was collected at baseline and week 12 for analysis of high-sensitivity C-reactive protein and 25-hydroxyvitamin D levels. Repeated-measures analysis was performed on data to assess change from baseline at 24 weeks. RESULTS: Of 409 participants initially enrolled, 252 completed all follow-up visits during the 6 month evaluation. Participants were predominantly white (81%) and female (73%), with a mean age of 49.1 years (15.44) and an average of 8.0 (9.26) years of chronic pain. At baseline, 52% of patients reported symptoms consistent with depression. At 24 weeks, significantly decreased pain severity (−23%) and interference (−28%) were seen. Significant improvements in mood, stress, quality of life, fatigue, sleep and well-being were also observed. Mean 25-hydroxyvitamin D levels increased from 33.4 (17.05) ng/mL at baseline to 39.6 (16.68) ng/mL at week 12. CONCLUSIONS: Among participants completing an integrative medicine program for chronic pain, significant improvements were seen in pain as well as other relevant patient-reported outcome measures. TRIAL REGISTRATION: ClinicalTrials.gov, NCT0118634

    The age and paleoclimate implications of relict periglacial block deposits on the New England Tablelands, Australia

    No full text
    Pleistocene periglacial activity in eastern Australia was widespread and has been predicted to have extended along much of the east coast. This paper describes block deposits in the New England Tablelands, Australia, as far north as 30°S. These deposits are characterized by openwork blocks on slopes below the angle of repose. The deposits are positioned where frost cracking was significant and range in area up to 8 ha. Surface exposure dating using the cosmogenic nuclide 36Cl from four block deposits indicate all sites were active late during the last glacial cycle, with a concentration of activity between 15-30 ka. Modern temperature measurements from block deposits highlight the importance of local topography for promoting freezing. Periglacial deposits are likely to have been more extensive than previously recognized at these northern limits, and mean annual temperature more than 8°C colder than today

    Microfluidic devices fabricated in poly(methyl methacrylate) using hot-embossing with integrated sampling capillary and fiber optics for fluorescence detection

    No full text
    High-aspect-ratio microstructures have been prepared using hot-embossing techniques in poly(methyl methacrylate) (PMMA) from Ni-based molding dies prepared using LIGA (Lithographie, Galvanoformung, Abformung). Due to the small amount of mask undercutting associated with X-ray lithography and the high energy X-ray beam used during photoresist patterning, deep structures with sharp and smooth sidewalls have been prepared. The Ni-electroforms produced devices with minimal replication errors using hot-embossing at a turn around time of approximately 5 min per device. In addition, several different polymers (with different glass transition temperatures) could be effectively molded with these Ni-electroforms and many devices (\u3e300) molded with the same master without any noticeable degradation. The PMMA devices consisted of deep and narrow channels for insertion of a capillary for the automated electrokinetic loading of sample into the microfluidic device and also, a pair of optical fibers for shuttling laser light to the detection zone and collecting the resulting emission for fluorescence analysis. Electrophoretic separations of double-stranded DNA ladders Phi X174 digested with Hae III) were performed with fluorescence detection accomplished using near-IR excitation. It was found that the narrow width of the channels did not contribute significantly to electrophoretic zone broadening and the plate numbers generated in the extended length separation channel allowed sorting of the 271/281 base pair fragments associated with this sizing ladder when electrophoresed in methylcellulose entangled polymer solutions. The dual fiber detector produced sub-attomole detection limits with the entire detector, including laser source, electronics and photon transducer, situated in a single box measuring 3\u27\u27 x 10 x 14

    Aquacultured Rainbow Trout (\u3ci\u3eOncorhynchus mykiss\u3c/i\u3e) Possess a Large Core Intestinal Microbiota That Is Resistant to Variation in Diet and Rearing Density

    Get PDF
    As global aquaculture fish production continues to expand, an improved understanding of how environmental factors interact in fish health and production is needed. Significant advances have been made toward economical alternatives to costly fishmealbased diets, such as grain-based formulations, and toward defining the effect of rearing density on fish health and production. Little research, however, has examined the effects of fishmeal- and grain-based diets in combination with alterations in rearing density. Moreover, it is unknown whether interactions between rearing density and diet impact the composition of the fish intestinal microbiota, which might in turn impact fish health and production. We fed aquacultured adult rainbow trout (Oncorhynchus mykiss) fishmeal- or grain-based diets, reared them under high- or low-density conditions for 10 months in a single aquaculture facility, and evaluated individual fish growth, production, fin indices, and intestinal microbiota composition using 16S rRNA gene sequencing. We found that the intestinal microbiotas were dominated by a shared core microbiota consisting of 52 bacterial lineages observed across all individuals, diets, and rearing densities. Variations in diet and rearing density resulted in only minor changes in intestinal microbiota composition despite significant effects of these variables on fish growth, performance, fillet quality, and welfare. Significant interactions between diet and rearing density were observed only in evaluations of fin indices and the relative abundance of the bacterial genus Staphylococcus. These results demonstrate that aquacultured rainbow trout can achieve remarkable consistency in intestinal microbiota composition and suggest the possibility of developing novel aquaculture strategies without overtly altering intestinal microbiota composition

    The BraveNet prospective observational study on integrative medicine treatment approaches for pain

    Get PDF
    Abstract Background Chronic pain affects nearly 116 million American adults at an estimated cost of up to $635 billion annually and is the No. 1 condition for which patients seek care at integrative medicine clinics. In our Study on Integrative Medicine Treatment Approaches for Pain (SIMTAP), we observed the impact of an integrative approach on chronic pain and a number of other related patient-reported outcome measures. Methods Our prospective, non-randomized, open-label observational evaluation was conducted over six months, at nine clinical sites. Participants received a non-standardized, personalized, multimodal approach to chronic pain. Validated instruments for pain (severity and interference levels), quality of life, mood, stress, sleep, fatigue, sense of control, overall well-being, and work productivity were completed at baseline and at six, 12, and 24 weeks. Blood was collected at baseline and week 12 for analysis of high-sensitivity C-reactive protein and 25-hydroxyvitamin D levels. Repeated-measures analysis was performed on data to assess change from baseline at 24 weeks. Results Of 409 participants initially enrolled, 252 completed all follow-up visits during the 6 month evaluation. Participants were predominantly white (81%) and female (73%), with a mean age of 49.1 years (15.44) and an average of 8.0 (9.26) years of chronic pain. At baseline, 52% of patients reported symptoms consistent with depression. At 24 weeks, significantly decreased pain severity (−23%) and interference (−28%) were seen. Significant improvements in mood, stress, quality of life, fatigue, sleep and well-being were also observed. Mean 25-hydroxyvitamin D levels increased from 33.4 (17.05) ng/mL at baseline to 39.6 (16.68) ng/mL at week 12. Conclusions Among participants completing an integrative medicine program for chronic pain, significant improvements were seen in pain as well as other relevant patient-reported outcome measures. Trial Registration ClinicalTrials.gov, NCT0118634
    corecore