13,264 research outputs found
Laser net - A concept for monitoring wingtip vortices on runways
Network of laser beams passes over runway to photodetectors on opposite side, magnitude of beam deflection indicates magnitude of density gradient encountered. Visual display of beam deflections affects go, no-go decision for takeoff and landing
Muscular dystrophy meets protein biochemistry, the mother of invention
Muscular dystrophies result from a defect in the linkage between the muscle fiber cytoskeleton and the basement membrane (BM). Congenital muscular dystrophy type MDC1A is caused by mutations in laminin α2 that either reduce its expression or impair its ability to polymerize within the muscle fiber BM. Defects in this BM lead to muscle fiber damage from the force of contraction. In this issue of the JCI, McKee and colleagues use a laminin polymerization–competent, designer chimeric BM protein in vivo to restore function of a polymerization-defective laminin, leading to normalized muscle structure and strength in a mouse model of MDC1A. Delivery of such a protein to patients could ameliorate many aspects of their disease
The GeV-TeV Connection in Galactic gamma-ray sources
Recent observations with atmospheric Cherenkov telescope systems such as
H.E.S.S. and MAGIC have revealed a large number of new sources of
very-high-energy (VHE) gamma-rays from 100 GeV - 100 TeV, mostly concentrated
along the Galactic plane. At lower energies (100 MeV - 10 GeV) the
satellite-based instrument EGRET revealed a population of sources clustering
along the Galactic Plane. Given their adjacent energy bands a systematic
correlation study between the two source catalogues seems appropriate. Here,
the populations of Galactic sources in both energy domains are characterised on
observational as well as on phenomenological grounds. Surprisingly few common
sources are found in terms of positional coincidence and spectral consistency.
These common sources and their potential counterparts and emission mechanisms
will be discussed in detail. In cases of detection only in one energy band, for
the first time consistent upper limits in the other energy band have been
derived. The EGRET upper limits are rather unconstraining due to the
sensitivity mismatch to current VHE instruments. The VHE upper limits put
strong constraints on simple power-law extrapolation of several of the EGRET
spectra and thus strongly suggest cutoffs in the unexplored energy range from
10 GeV - 100 GeV. Physical reasons for the existence of cutoffs and for
differences in the source population at GeV and TeV energies will be discussed.
Finally, predictions will be derived for common GeV - TeV sources for the
upcoming GLAST mission bridging for the first time the energy gap between
current GeV and TeV instruments.Comment: (1) Kavli Institute for Particle Astrophysics and Cosmology (KIPAC),
Stanford, USA (2) Stanford University, W.W. Hansen Experimental Physics Lab
(HEPL) and KIPAC, Stanford, USA (3) ICREA & Institut de Ciencies de l'Espai
(IEEC-CSIC) Campus UAB, Fac. de Ciencies, Barcelona, Spain. (4) School of
Physics and Astronomy, University of Leeds, UK. Paper Submitted to Ap
Front-End electronics configuration system for CMS
The four LHC experiments at CERN have decided to use a commercial SCADA
(Supervisory Control And Data Acquisition) product for the supervision of their
DCS (Detector Control System). The selected SCADA, which is therefore used for
the CMS DCS, is PVSS II from the company ETM. This SCADA has its own database,
which is suitable for storing conventional controls data such as voltages,
temperatures and pressures. In addition, calibration data and FE (Front-End)
electronics configuration need to be stored. The amount of these data is too
large to be stored in the SCADA database [1]. Therefore an external database
will be used for managing such data. However, this database should be
completely integrated into the SCADA framework, it should be accessible from
the SCADA and the SCADA features, e.g. alarming, logging should be benefited
from. For prototyping, Oracle 8i was selected as the external database manager.
The development of the control system for calibration constants and FE
electronics configuration has been done in close collaboration with the CMS
tracker group and JCOP (Joint COntrols Project)(1).
(1)The four LHC experiments and the CERN IT/CO group has merged their efforts
to build the experiments controls systems and set up the JCOP at the end of
December, 1997 for this purpose.Comment: 3 pages, 4 figures, Icaleps'01 conference PSN WEDT00
\u3ci\u3eAcrobasis\u3c/i\u3e Shoot Moth (Lepidoptera: Pyralidae) Infestation-Tree Height Link in a Young Black Walnut Plantation
Acrobasis shoot moth infestations were evaluated in a young black walnut progeny test for 4 years, from ages 3 to 6. Infestation levels were greatest on the largest trees in the fourth and fifth year after plantation establishment, and were declining by the sixth year. Acrobasis infestation appears to be a problem primarily on young trees less than 2.5 m in height. There was no evidence for genetic resistance to Acrobasis infestation in black walnut
Recent Reforms in Campaign Finance Regulations and Their Potential Effect on Federal Elections and Reflections on Washington as a Congressional Intern
In the spring of 1975, upon learning that I had been selected as a summer intern in Congressman Gunn McKay\u27s office, I thought that such an experience might readily serve as the basis for my senior Honors project. I discussed this possibility with Dr. Douglas Alder, the Honors Program Director, and Dr. Wendell Anderson, the intern advisor. With their approval, I decided to write one paper on my impressions of Washington as an intern and then upon my return to school, research and write another paper on an issue related to Congress. This is the reason my thesis project is in two parts.
When I selected the topic of Campaign Finance in the fall of 1975 I had little anticipation of the subject changing as greatly as it has. It has been fascinating to observe the changes invoked by the Supreme Court ruling, though frustrating in trying to complete the project. Because the topic is continuing to change and other reforms may still be made, some of the anticipated effects of the recent changes may not come to fruition. Nonetheless, I feel there is merit in examining where we are in the spring of 1976 and where that may lead us in the future
An indirect enzyme-linked immunosorbent assay for the detection of Brucella melitensis antibody in goat milk
Brucella melitensis is the cause of brucellosis in sheep and goats resulting in abortion. Few cases of B. melitensis infection in goats have occurred in the United States over the last 25 years. However, vigilance for brucellosis in goats must be maintained as it is in the bovine milk industry to ensure it is not introduced into the U.S. goat population. The objective of this study was to develop a sensitive and specific indirect enzyme-linked immunoassay (iELISA) for the detection of B. melitensis antibody in goat milk. Brucella salt-extractable protein extract (BCSP) was employed as an antigen, and a horse-radish peroxidase labeled polyclonal anti-goat antibody was used as an anti-species conjugate. Thirteen of 13 (100%) individual positive milk samples tested positive, and 134 of 134 (100%) negative bulk milk samples tested negative by the iELISA developed. Three positive samples of high, medium, and low titer were used in simulating one positive animal in a negative herd. By this estimation, one high titer animal could be detected in a herd of greater than 1600 animals. Estimations for medium and low titer animals were one positive animal in a herd of less than 200 and 50 animals, respectively. The iELISA developed was found to be sensitive and specific and shows promise as a bulk milk test for the detection of Brucella melitensis antibody in goat milk
An Evaluation of the Design Requirements of the H-1 Upgrades Helicopter Blade Fold Racks
The United States Marine Corps contracted Bell Helicopter Textron Inc. (BHTI) to develop and field new versions of the aging UH-1N and AH-1W helicopters. As part of the development effort of the H-1 Upgrades, BHTI was tasked with development of a folding rotor system and the associated equipment necessary to support main rotor folding operations. The blade fold equipment (BFE) was constrained throughout the development process by a list of conflicting requirements. The requirements for commonality, versatility, simplicity, light weight, rapid application, and durability, while each was generally reasonable, could not be satisfied with one set of equipment. The resulting BFE was ineffective for everyday use.
The purpose of this thesis was to evaluate the design requirements of the BFE, specifically the blade fold racks. An investigation of the source of requirements was conducted, followed by interviews with system experts and end users. Additional data were gathered during the program-sponsored test events from January through May 2005.
In order to develop a suitable and effective set of BFE, the H-1 Upgrades program should reduce the set of design requirements on the new blade fold racks, specifically:
1. Modify the H-1 Upgrades aircraft to incorporate an automatic folding rotor system or a blade indexing motor.
2. Redesign the blade fold racks for a reduced set of configurations and load conditions.
3. Consider a simple, one piece, clamping blade fold rack
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