Phase and amplitude scintillations of microwave signals over an elevated atmospheric path

Phase and amplitude scintillations of microwave signals over elevated atmospheric path for obtaining atmospheric density profile

Comparing groups of Brazilian cattle farmers with different levels of intention to use improved natural grassland

This study used the Theory of Planned Behavior (TPB) to analyze the intention of Brazilian farmers to use improved natural grassland. The TPB hypothesizes that the adoption of an innovation is driven by the intention to use it, which in turn is determined by three socio-psychological constructs: attitude, subjective norm, and perceived behavioral control. These constructs are derived from beliefs. The theoretical framework and model were applied to a sample of 214 Brazilian cattle farmers. Based on the socio-psychological constructs that influence intention, two groups of farmers were identified; farmers that were willing and farmers that were unwilling to use improved natural grassland. Results showed that compared to unwilling farmers, willing farmers evaluated the use of improved natural grassland on their farms more favorably (attitude), they felt a greater social pressure upon them to adopt this innovation (social norm), and they reported a higher capability (perceived behavioral control) to use improved natural grassland. Willing and unwilling farmers also differed in their behavioral beliefs concerning the outcomes of using improved natural grassland, their normative beliefs concerning important others, and their control beliefs concerning factors that could facilitate or inhibit the use of improved natural grassland. The two groups did not differ in most of their socioeconomic characteristics, but did differ in their goals and relative risk attitudes

Observations of the 8 December 1987 occultation of AG+40 deg 0783 by 324 Bamberga

The occultation of AG+40 deg 0783 by 324 Bamberga on 8 December 1987 was observed at 13 sites in the United States, Japan, and China. At four sites the event was observed photoelectrically; the other observations were visual. A least-squares fit of a circular limb profile to the data gives a diameter of 227.6 + or - 1.9 km. However, this solution is inconsistent with a negative visual observation near the northern edge of the ground track. The inconsistency cannot be removed by assuming an elliptical profile. The data suggest that Bamberga, despite its low-amplitude lightcurve, may depart significantly from a spherical or ellipsoidal shape. The asteroid also appears to be at least 10 percent smaller than indicated by infrared radiometry

Satellite‐Based Monitoring of Irrigation Water Use: Assessing Measurement Errors and Their Implications for Agricultural Water Management Policy

Reliable accounting of agricultural water use is critical for sustainable water management. However, the majority of agricultural water use is not monitored, with limited metering of irrigation despite increasing pressure on both groundwater and surface water resources in many agricultural regions worldwide. Satellite remote sensing has been proposed as a low-cost and scalable solution to fill widespread gaps in monitoring of irrigation water use in both developed and developing countries, bypassing the technical, socioeconomic, and political challenges that to date have constrained in situ metering. In this paper, we show through a systematic meta-analysis that the relative accuracy of different satellite-based irrigation water use monitoring approaches remains poorly understood, with evidence of large uncertainties when water use estimates are validated against in situ irrigation data at both field and regional scales. Subsequently, we demonstrate that water use measurement errors result in large economic welfare losses for farmers and may negatively impact ability of policies to limit acute and nonlinear externalities of irrigation abstraction on both the environment and other water users. Our findings highlight that water resource planners must consider the trade-offs between accuracy and costs associated with different water use accounting approaches. Remote sensing has an important role to play in supporting improved agricultural water accounting—both independently and in combination with in situ monitoring. However, greater transparency and evidence is needed about underlying uncertainties in satellite-based models, along with how these measurement errors affect the performance of associated policies to manage different short- and long-term externalities of irrigation water use

NBS monograph

From Introduction: "This report is a compilation of the MeV Total Neutron Cross Section data measured at the U.S. National Bureau of Standards.

A Mercury Lander Mission Concept Study for the Next Decadal Survey

Mariner 10 provided our first closeup reconnaissance of Mercury during its three flybys in 1974 and 1975. MESSENGERs 20112015 orbital investigation enabled numerous discoveries, several of which led to substantial or complete changes in our fundamental understanding of the planet. Among these were the unanticipated, widespread presence of volatile elements (e.g., Na, K, S); a surface with extremely low Fe abundance whose darkening agent is likely C; a previously unknown landformhollows that may form by volatile sublimation from within rocks exposed to the harsh conditions on the surface; a history of expansive effusive and explosive volcanism; substantial radial contraction of the planet from interior cooling; offset of the dipole moment of the internal magnetic field northward from the geographic equator by ~20% of the planets radius; crustal magnetization, attributed at least in part to an ancient field; unexpected seasonal variability and relationships among exospheric species and processes; and the presence in permanently shadowed polar terrain of water ice and other volatile materials, likely to include complex organic compounds. Mercurys highly chemically reduced and unexpectedly volatile-rich composition is unique among the terrestrial planets and was not predicted by earlier hypotheses for the planets origin. As an end-member of terrestrial planet formation, Mercury holds unique clues about the original distribution of elements in the earliest stages of the Solar System and how planets (and exoplanets) form and evolve in close proximity to their host stars. The BepiColombo mission promises to expand our knowledge of this planet and to shed light on some of the mysteries revealed by the MESSENGER mission. However, several fundamental science questions raised by MESSENGERs pioneering exploration of Mercury can only be answered with in situ measurements from the planets surface

Plasma Electronics

Contains reports on eight research projects.National Science Foundation (Grant G-24073)United States Navy, Office of Naval Research (Contract Nonr-1841(49))Lincoln Laboratory (Purchase Order DDL B-00368)United States ArmyUnited States NavyUnited States Air Force (Contract AF19(604)-7400

Non Degenerate Dual Atomic Parametric Amplifier: Entangled Atomic Fields

In this paper, we investigate the dynamics of two coupled quantum degenerate atomic fields (BEC) interacting with two classical optical fields in the nonlinear atom optics regime. Two photon interaction produces entangled atom-atom pairs which exhibit nonclassical correlations. Since the system involves the creation of two correlated atom pairs, we call it the nondegenerate dual atomic parametric amplifier.Comment: 5 figure