2,014 research outputs found
Shuttle payload S-band communications system
The Shuttle payload S-band communications system design, operational capabilities, and performance are described in detail. System design requirements, overall system and configuration and operation, and laboratory/flight test results are presented. Payload communications requirements development is discussed in terms of evolvement of requirements as well as the resulting technical challenges encountered in meeting the initial requirements. Initial design approaches are described along with cost-saving initiatives that subsequently had to be made. The resulting system implementation that was finally adopted is presented along with a functional description of the system operation. A description of system test results, problems encountered, how the problems were solved, and the system flight experience to date is presented. Finally, a summary of the advancements made and the lessons learned is discussed
A New Solid Deuterium Source of Ultra-Cold Neutrons
In polarized neutron decay, the angular correlation between the neutron spin and the
direction of emission of the electron is characterized by the coefficient A. Measuring
A involves determining the forward-backward asymmetry of the decay beta with
respect to the direction of the neutron polarization. The value of A, when combined
with measurements of the neutron lifetime, determines the values of the vector and
axial vector weak coupling constants, Gv and GA. The value of Gv can also be
determined by measurements of superallowed nuclear beta decay and by requiring
that the Cabibo-Kobayashi-Maskawi (CKM) mixing matrix be unitary along with the
measured value of other elements of the CKM matrix
Cognitive processing in bipolar disorder conceptualized using the Interactive Cognitive Subsystems (ICS) model
Manage Weeds on Your Farm: A Guide to Ecological Strategies
Manage Weeds on Your Farm is a definitive guide to understanding agricultural weeds and how to manage them efficiently, effectively and ecologically—for organic and conventional farmers alike.
With the growing spread of herbicide-resistant weeds and with the public’s embrace of sustainably raised foods, farmers everywhere, both organic and conventional, are seeking better ways to eliminate or reduce their use of synthetic herbicides. The ecological approach to weed management seeks to first understand the biology and behavior of problem weeds and then to develop an integrated set of control strategies that exploit their weaknesses.
Manage Weeds on Your Farm: A Guide to Ecological Strategies provides you with in-depth information about dozens of agricultural weeds found throughout the country and the best ways of managing them. In Part One, the book begins with a general discussion of weeds: their biology, behavior and the characteristics that influence how to best control their populations. It then describes the strengths and limitations of the most common cultural management practices, physical practices and cultivation tools. Part Two is a reference section that describes the identification, ecology and management of 63 of the most common and difficult-to-control weed species found in the United States.
Ecological weed management is knowledge intensive, rather than input intensive. But it doesn’t have to be excessively labor intensive. Manage Weeds on Your Farm shows you how to outsmart your weeds by identifying the right tactic for the right weed at the right time, which will reduce as much as possible the labor required, while ensuring your weeds don’t impact crop yields.
Note: Manage Weeds on Your Farm is focused on the weeds of arable cropping systems. It does not discuss the management of weeds in forests, turf, permanent pastures or perennial bioenergy crops. Weed management issues in forage production are discussed to some extent since forages are often rotated with other crops
Photoproduction of Positive Mesons from Hydrogen: Results
The center-of-mass differential cross section for photoproduction of positive pions from hydrogen has been measured by the methods described in the two previous abstracts, in the angular range 40° to 150°, for photons from 220 to 475 Mev. (Photon energies refer to the Laboratory System.) Results obtained by the two methods are in essential agreement. At 90°, dσ/dω has a maximum of 2.7 X 10^(-29) cm^2/sterad near 280 Mev and falls by a factor 5 at 450 Mev. The maximum in the excitation curve is even more pronounced at larger angles, but less pronounced at smaller ones. At 40° (c.m.) the peak occurs near 350 Mev and at 450 Mev the cross section has decreased only to 0.7 the, peak value. Angular distributions in the center-of-mass system show a marked assymetry about 90°, which changes character from low energy to high. Below 325 Mev, there ii a backward maximum, whereas above 375 Mev, there is a forward maximum. The total cross section reaches a maximum near 290 Mev and decreases by about a factor 3 at 450 Mev. The results below 300 Mev agree with the data already reported from Berkeley and Cornell
Hyperdynamic right heart function in Graves' hyperthyroidism measured by echocardiography normalises on restoration of euthyroidism
Graves' hyperthyroidism commonly causes tachycardia and may result in pulmonary hypertension and high output cardiac failure. There is limited information regarding the effect of treatment on cardiac function measured using modern echocardiographic techniques.Eight individuals with Graves' hyperthyroidism, aged 22-64 years, underwent comprehensive transthoracic echocardiography at three time points: before treatment, two weeks after commencement of carbimazole, and at six months or more when euthyroid. Exercise capacity was assessed using the 6-minute-walk-distance (6MWT), and quality of life was assessed by Medical Outcome Study 36-item Short-Form Health Status Survey.All individuals were rendered euthyroid by final assessment. At presentation, there was evidence of hyperdynamic right ventricular function as measured by peak systolic velocity of the free wall of the tricuspid annulus, tricuspid annular plane systolic excursion and right ventricular ejection fraction, which normalised after resolution of thyrotoxicosis. Baseline heart rate correlated significantly with severity of the thyrotoxicosis for either free T4 (r = 0.91, p=0.01) or free T3 (r=0.94, p=0.001). No individual had measurable pulmonary hypertension. Cardiac output was significantly lower in the euthyroid compared to the thyrotoxic state (p=0.03). A higher baseline TSH-receptor antibody titre corresponded to a greater improvement in exercise capacity (r=0.76,
Structured interviews for the Glasgow Outcome Scale and the extended Glasgow Outcome Scale: Guidelines for their use
The Glasgow Outcome Scale (GOS) is the most widely used outcome measure after traumatic brain injury, but it is increasingly recognized to have important limitations. It is proposed that shortcomings of the GOS can be addressed by adopting a standard format for the interview used to assign outcome. A set of guidelines are outlined that are directed at the main problems encountered in applying the GOS. The guidelines cover the general principles underlying the use of the GOS and common practical problems of applying the scale. Structured interview schedules are described for both the five-point GOS and an extended eight-point GOS (GOSE). An interrater reliability study of the structured interviews for the GOS and GOSE yielded weighted kappa values of 0.89 and 0.85, respectively. It is concluded that assessment of the GOS using a standard format with a written protocol is practical and reliable
Fractional urinary fluoride excretion of 6-7-year-old children attending schools in low-fluoride and naturally fluoridated areas in the UK
Phosphoinositide 3-kinase δ regulates membrane fission of Golgi carriers for selective cytokine secretion
The PI3K isoform p110δ is required for TNF trafficking and secretion
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