13,956 research outputs found
J-hook latching device
Described here is a latching device for latching two items together that has a housing and a shaft mounted to one item such that rotation of the shaft by a sprocket causes the shaft to move longitudinally up and down. The shaft has one end extending beyond the housing with an alignment cone attached to this end for engaging a receptor on the other item. A latch mounted to a shaft by a traveling nut provides a pivot point for the latch so that rotation of the shaft causes the pivot point of the latch to translate along the longitudinal axis of the shaft. Camming surfaces and a camming spring are used for rotating the latch so that the latch will engage and disengage a receptor on the other item
Imaging studies of comets
Schmidt camera plates of comet Bradfield were secured on several nights in October 1987. The images of October 20 show the development of a huge bend in the plasma tail travelling several hundred kilometers per second down the tail; the likely solar-wind origin of this event is being explored. A charged coupled device (CCD) detector has been obtained. Calibration of the CCD is still underway, but high-quality, filtered cometary images shoud be possible in the near future
EVALUATING MERGERS IN FOOD INDUSTRIES UNDER PROCEDURES FOR LITIGATION OR REGULATION
Mergers, market power, antitrust analysis, Agribusiness, Agricultural and Food Policy,
The HELP inequality on trees
We establish analogues of Hardy and Littlewood's integro-differential equation for Schrödinger-type operators on metric and discrete trees, based on a generalised strong limit-point property of the graph Laplacian
Assessment of pulmonary edema: principles and practice
Pulmonary edema increasingly is recognized as a perioperative complication affecting outcome. Several risk factors have been identified, including those of cardiogenic origin, such as heart failure or excessive fluid administration, and those related to increased pulmonary capillary permeability secondary to inflammatory mediators.
Effective treatment requires prompt diagnosis and early intervention. Consequently, over the past 2 centuries a concentrated effort to develop clinical tools to rapidly diagnose pulmonary edema and track response to treatment has occurred. The ideal properties of such a tool would include high sensitivity and specificity, easy availability, and the ability to diagnose early accumulation of lung water before the development of the full clinical presentation. In addition, clinicians highly value the ability to precisely quantify extravascular lung water accumulation and differentiate hydrostatic from high permeability etiologies of pulmonary edema.
In this review, advances in understanding the physiology of extravascular lung water accumulation in health and in disease and the various mechanisms that protect against the development of pulmonary edema under physiologic conditions are discussed. In addition, the various bedside modalities available to diagnose early accumulation of extravascular lung water and pulmonary edema, including chest auscultation, chest roentgenography, lung ultrasonography, and transpulmonary thermodilution, are examined. Furthermore, advantages and limitations of these methods for the operating room and intensive care unit that are critical for proper modality selection in each individual case are explored
Early Scientific Results and Future Prospects for the Rejuvenated Hubble Space Telescope
Following the extraordinarily successful Servicing Mission 4 (SM4) of Hubble Space Telescope (HST) in May of 2009, the Observatory is now fully equipped with a broad array of powerful science instruments that put it at the pinnacle of its scientific power. Relevant to the subject matter of the Beyond 2010 Conference, HST will be well-placed over the next five-plus years to advance our knowledge of the formation of high-redshift galaxies and their growth with cosmic time; the emergence of structure in the early universe via Dark Matter-driven gravitational instability; and the universe's expansion history and any resulting implications for the temporal character of Dark Energy. These are fitting projects for the iconic facility now celebrating its 20th anniversary in orbit
Secrecy Sum-Rates for Multi-User MIMO Regularized Channel Inversion Precoding
In this paper, we propose a linear precoder for the downlink of a multi-user
MIMO system with multiple users that potentially act as eavesdroppers. The
proposed precoder is based on regularized channel inversion (RCI) with a
regularization parameter and power allocation vector chosen in such a
way that the achievable secrecy sum-rate is maximized. We consider the
worst-case scenario for the multi-user MIMO system, where the transmitter
assumes users cooperate to eavesdrop on other users. We derive the achievable
secrecy sum-rate and obtain the closed-form expression for the optimal
regularization parameter of the precoder using
large-system analysis. We show that the RCI precoder with
outperforms several other linear precoding schemes, and
it achieves a secrecy sum-rate that has same scaling factor as the sum-rate
achieved by the optimum RCI precoder without secrecy requirements. We propose a
power allocation algorithm to maximize the secrecy sum-rate for fixed .
We then extend our algorithm to maximize the secrecy sum-rate by jointly
optimizing and the power allocation vector. The jointly optimized
precoder outperforms RCI with and equal power allocation
by up to 20 percent at practical values of the signal-to-noise ratio and for 4
users and 4 transmit antennas.Comment: IEEE Transactions on Communications, accepted for publicatio
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