407 research outputs found
Acquisition and use of Orlando, Florida and Continental Airbus radar flight test data
Westinghouse is developing a lookdown pulse Doppler radar for production as the sensor and processor of a forward looking hazardous windshear detection and avoidance system. A data collection prototype of that product was ready for flight testing in Orlando to encounter low level windshear in corroboration with the FAA-Terminal Doppler Weather Radar (TDWR). Airborne real-time processing and display of the hazard factor were demonstrated with TDWR facilitated intercepts and penetrations of over 80 microbursts in a three day period, including microbursts with hazard factors in excess of .16 (with 500 ft. PIREP altitude loss) and the hazard factor display at 6 n.mi. of a visually transparent ('dry') microburst with TDWR corroborated outflow reflectivities of +5 dBz. Range gated Doppler spectrum data was recorded for subsequent development and refinement of hazard factor detection and urban clutter rejection algorithms. Following Orlando, the data collection radar was supplemental type certified for in revenue service on a Continental Airlines Airbus in an automatic and non-interferring basis with its ARINC 708 radar to allow Westinghouse to confirm its understanding of commercial aircraft installation, interface realities, and urban airport clutter. A number of software upgrades, all of which were verified at the Receiver-Transmitter-Processor (RTP) hardware bench with Orlando microburst data to produce desired advanced warning hazard factor detection, included some preliminary loads with automatic (sliding window average hazard factor) detection and annunciation recording. The current (14-APR-92) configured software is free from false and/or nuisance alerts (CAUTIONS, WARNINGS, etc.) for all take-off and landing approaches, under 2500 ft. altitude to weight-on-wheels, into all encountered airports, including Newark (NJ), LAX, Denver, Houston, Cleveland, etc. Using the Orlando data collected on hazardous microbursts, Westinghouse has developed a lookdown pulse Doppler radar product with signal and data processing algorithms which detect realistic microburst hazards and has demonstrated those algorithms produce no false alerts (or nuisance alerts) in urban airport ground moving vehicle (GMTI) and/or clutter environments
Sensory Aids for the Handicapped: A Challenge for Modern Engineering Technology
The search for sensory aids for the blind and deaf has revealed many possibilities, but at present there is no aid which to any great degree replaces the defective sensory channel. This paper summarizes the major developments in sensory aids in an attempt to stimulate interest in this problem among engineers and scientists
Saberliner flight test for airborne wind shear forward looking detection and avoidance radar systems
Westinghouse conducted a flight test with its Sabreliner AN/APG-68 instrumented radar to assess the urban discrete/ground moving vehicle clutter environment. Glideslope approaches were flown into Washington National, BWI, and Georgetown, Delaware, airports employing radar mode timing, waveform, and processing configurations plausible for microburst windshear avoidance. The perceptions, both general and specific, of the clutter environment furnish an empirical foundation for beginning low false alarm detection algorithm development
A chi-squared time-frequency discriminator for gravitational wave detection
Searches for known waveforms in gravitational wave detector data are often
done using matched filtering. When used on real instrumental data, matched
filtering often does not perform as well as might be expected, because
non-stationary and non-Gaussian detector noise produces large spurious filter
outputs (events). This paper describes a chi-squared time-frequency test which
is one way to discriminate such spurious events from the events that would be
produced by genuine signals. The method works well only for broad-band signals.
The case where the filter template does not exactly match the signal waveform
is also considered, and upper bounds are found for the expected value of
chi-squared.Comment: 18 pages, five figures, RevTex
First geodetic observations using new VLBI stations ASKAP-29 and WARK12M
We report the results of a successful 7 hour 1.4 GHz VLBI experiment using
two new stations, ASKAP-29 located in Western Australia and WARK12M located on
the North Island of New Zealand. This was the first geodetic VLBI observing
session with the participation of these new stations. We have determined the
positions of ASKAP-29 and WARK12M. Random errors on position estimates are
150-200 mm for the vertical component and 40-50 mm for the horizontal
component. Systematic errors caused by the unmodeled ionosphere path delay may
reach 1.3 m for the vertical component.Comment: 11 pages, 6 flgures, 4 table
PAX6 suppression of glioma angiogenesis and the expression of vascular endothelial growth factor A
We reported that PAX6 suppresses glioblastoma cell growth in vivo and anchorage-independent growth without significant alteration of cell proliferation in vitro, suggesting that PAX6 may alter the tumor microenvironment. Because we found that PAX6 downregulates expression of the gene encoding vascular endothelial growth factor A (VEGFA) in glioma cells, we used a subcutaneous xenograft model to verify PAX6 suppression of VEGFA-induced angiogenesis based on CD31-immunostaining of endothelial cells. The results showed a significant reduction of VEGFA at the transcription level in PAX6-transfected cells in xenografts and PAX6 has a suppressive effect on the microvascular amplification typically seen in glioblastoma. We showed that PAX6 suppression of VEGFA expression requires its DNA binding-domain. The C-terminal truncation mutant of PAX6, however, did not show the dominant negative function in regulating VEGFA expression that it showed previously in regulating MMP2 expression. In the glioma cell line U251HF, we further determined that blocking the PI3K/Akt signaling pathway with either adenoviral-mediated PTEN expression or LY294002 enhanced PAX6-mediated suppression of VEGFA in an additive manner; thus, PAX6-mediated suppression of VEGFA is not via the canonical pathway through HIF1A. These two VEGFA-regulatory pathways can also be similarly modulated in another malignant glioma cell line, U87, but not in LN229 where the basal VEGFA level is low and PTEN is wild-type. PAX6 suppression of VEGFA appears to be blocked in LN229. In conclusion, our data showed that PAX6 can initiate in glioma cells a new signaling pathway independent of PI3K/Akt-HIF1A signaling to suppress VEGFA expression
EFEMP1 suppresses malignant glioma growth and exerts its action within the tumor extracellular compartment
<p>Abstract</p> <p>Purpose</p> <p>There are conflicting reports regarding the function of EFEMP1 in different cancer types. In this study, we sought to evaluate the role of EFEMP1 in malignant glioma biology.</p> <p>Experimental Design</p> <p>Real-time qRT-PCR was used to quantify <it>EFEMP1 </it>expression in 95 glioblastoma multiforme (GBM). Human high-grade glioma cell lines and primary cultures were engineered to express ectopic EFEMP1, a small hairpin RNA of EFEMP1, or treated with exogenous recombinant EFEMP1 protein. Following treatment, growth was assayed both <it>in vitro </it>and <it>in vivo </it>(subcutaneous (s.c.) and intracranial (i.c.) xenograft model systems).</p> <p>Results</p> <p>Cox regression revealed that EFEMP1 is a favorable prognostic marker for patients with GBM. Over-expression of EFEMP1 eliminated tumor development and suppressed angiogenesis, cell proliferation, and VEGFA expression, while the converse was true with knock-down of endogenous EFEMP1 expression. The EFEMP1 suppression of tumor onset time was nearly restored by ectopic VEGFA expression; however, overall tumor growth rate remained suppressed. This suggested that inhibition of angiogenesis was only partly responsible for EFEMP1's impact on glioma development. In glioma cells that were treated by exogenous EFEMP1 protein or over-expressed endogenous EFEMP1, the EGFR level was reduced and AKT signaling activity attenuated. Mixing of EFEMP1 protein with cells prior to s.c. and i.c. implantations or injection of the protein around the established s.c. xenografts, both significantly suppressed tumorigenicity.</p> <p>Conclusions</p> <p>Overall, our data reveals that EEFEMP1 suppresses glioma growth <it>in vivo</it>, both by modulating the tumor extracellular microenvironment and by altering critical intracellular oncogenic signaling pathways.</p
Development of a transdiagnostic stepped care programme for common adolescent mental health problems in Indian secondary schools: lessons from a pilot study examining acceptability and feasibility
Background
The ‘PRemIum for aDolEscents’ (PRIDE) project has developed a school-based, transdiagnostic stepped care programme for common adolescent mental health problems in India. The programme comprises a brief problem-solving intervention (‘Step 1’) followed by a personalised cognitive-behavioural intervention (‘Step 2’) for participants who do not respond to the first step.
Methods
A mixed-method design was used to evaluate the acceptability and feasibility of the stepped care programme in five schools in New Delhi. Participants were N = 80 adolescents (mean age = 15.3 years, females = 55%) with elevated mental symptoms and associated distress/impairment.
Results
61 (76%) of the enrolled sample were assessed following Step 1, from which 33 (54%) met non-remission criteria. Among these 33 non-remitted cases, 12 (36%) opted for Step 2 and five (42%) completed the full programme. The remaining non-remitted cases (n = 21, 64%) opted out of further treatment. Perceived resolution of the primary problem (n = 9, 43%) was the most common reason for opting out. The median time to complete each step was 22 and 70 days respectively, with a gap of 31 days between steps. Qualitative feedback from adolescents and counsellors indicated requirements for a shorter delivery schedule, greater continuity across steps and more collaborative decision-making.
Conclusions
This study provides preliminary evidence for a stepped care programme aimed at common adolescent mental health problems. Modifications are recommended to enhance the acceptability and feasibility of the programme in low-resource settings
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