1,941 research outputs found
Factors affecting farmland values in the United States
Farmland value has more than quadrupled since 1940. Before the early 1950\u27s, however, changes in farmland value had been closely related to changes in farm product prices and net farm income. But since that time, farmland value has increased substantially without a corresponding rise in net farm income. This widening spread between farmland values and net farm income created the interest for this study.
Our major objective was to identify the principal factors affecting farmland value and to estimate the effect of these variables. To accomplish this objective, we developed hypotheses to explain the changes in farmland value that included the effect of expected net farm income, government farm—program payments, expected capital gains, technological advance, farm enlargement, the number of voluntary transfers of farmland and an in creasing demand for land from a growing population
An Anthropometric Study of 38 Individuals With Prader-Labhart- Willi Syndrome
Weight, height, sitting height, and 24 other anthropometric variables (5 body circumferences, skinfolds at 7 sites, 4 head dimensions, and 8 hand and foot measurements) were obtained on 38 Prader-Labhart-Willi syndrome (PLWS) individuals (21 with apparent chromosome 15 deletions and 17 nondeletion cases) with an age range of 2 weeks to 38½ years. More than half of these individuals were measured on more than one occasion. The measurements confirmed the presence of short stature, small hands and feet, obesity, and narrow bi-frontal diameter in PLWS. No differences were found for the anthropometric measurements between the 2 chromosome subgroups. Inverse correlations were produced with linear measurements (eg, height, hand and foot lengths) and age, which indicated a deceleration of linear growth relative to normal individuals with increasing age
X-ray Line Diagnostics of Hot Accretion Flows around Black Holes
We compute X-ray emission lines from thermal plasma in hot accretion flows.
We show that line profiles are strong probes of the gas dynamics, and we
present line-ratio diagnostics which are sensitive to the distribution of mass
with temperature in the flow. We show how these can be used to constrain the
run of density with radius, and the size of the hot region. We also present
diagnostics which are primarily sensitive to the importance of recombination
versus collisional ionization, and which could help discriminate ADAFs from
photoionization-dominated accretion disk coronae. We apply our results to the
Galactic center source Sagittarius A* and to the nucleus of M87. We find that
the brightest predicted lines are within the detection capability of current
-ray instruments.Comment: 16 pages, 1 table, 9 figures, accepted to Ap
RIDS for Red Books from the Spacecraft Monitoring and Control Working Group of the CCSDS
This document presents a listing of the Review Item Dispositions (RIDs) to be presented to the The Consultative Committee for Space Data Systems (CCSDS)
OTF Mission Operations Prototype Status
A prototype system for monitoring spacecraft operations and control, including an alert system, is highlighted
Simultaneous multiwavelength observations of V404 Cygni during its 2015 June outburst decay strengthen the case for an extremely energetic jet-base
We present results of multiband optical photometry of the black hole X-ray
binary system V404 Cygni obtained using Wheaton College Observatory's 0.3m
telescope, along with strictly simultaneous INTEGRAL and Swift observations
during 2015 June 25.15--26.33 UT, and 2015 June 27.10--27.34 UT. These
observations were made during the 2015 June outburst of the source when it was
going through an epoch of violent activity in all wavelengths ranging from
radio to -rays. The multiwavelength variability timescale favors a
compact emission region, most likely originating in a jet outflow, for both
observing epochs presented in this work. The simultaneous INTEGRAL/Imager on
Board the Integral Satellite (IBIS) 20--40 keV light curve obtained during the
June 27 observing run correlates very strongly with the optical light curve,
with no detectable delay between the optical bands as well as between the
optical and hard X-rays. The average slope of the dereddened spectral energy
distribution was roughly flat between the - and -bands during the June
27 run, even though the optical and X-ray flux varied by 25 during
the run, ruling out an irradiation origin for the optical and suggesting that
the optically thick to optically thin jet synchrotron break during the
observations was at a frequency larger than that of -band, which is quite
extreme for X-ray binaries. These observations suggest that the optical
emission originated very close to the base of the jet. A strong H
emission line, probably originating in a quasi-spherical nebula around the
source, also contributes significantly in the -band. Our data, in
conjunction with contemporaneous data at other wavelengths presented by other
groups, strongly suggest that the jet-base was extremely compact and energetic
during this phase of the outburst.Comment: 15 pages, 2 tables, 5 figures. Accepted for publication in Ap
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An historical-descriptive assessment of the Performance Objective Program : a systems approach to individualizing instruction.
Spatial Attention Modulates Center-Surround Interactions in Macaque Visual Area V4
SummaryIn natural viewing, a visual stimulus that is the target of attention is generally surrounded by many irrelevant distracters. Stimuli falling in the receptive field surround can influence the neuronal response evoked by a stimulus appearing within the classical receptive field. Such modulation by task-irrelevant distracters may degrade the target-related neuronal signal. We therefore examined whether directing attention to a target stimulus can reduce the influence of task-irrelevant distracters on neuronal response. We find that in area V4 attention to a stimulus within a neuron's receptive field filters out a large fraction of the suppression induced by distracters appearing in the surround. When attention is instead directed to the surround stimulus, suppression is increased, thereby filtering out part of the neuronal response to the irrelevant distracter positioned within the receptive field. These findings demonstrate that attention modulates the neural mechanisms that give rise to center-surround interactions
Toward the synthesis of an acetal-free Tn antigen anti-cancer vaccine candidate
Cancer vaccines are a promising approach to cancer treatment by activating the immune system towards cancer cells. The challenge, however, comes with the identification of biomarkers correlated with cancer. Unfortunately, many oncotargets are simply upregulated in cancer; these are inappropriate vaccine targets as they are also present on healthy cells and therefore would ultimately initiate a very dangerous systemic immune response. In contrast, Tumor-Associated Carbohydrate Antigens (TACAs) are not found in healthy adult tissue but are found on over 90% of biopsied carcinomas. When incorporated into glycopeptides or other immunogenic scaffolds, these carbohydrate antigens have formed the basis of the development of anti-tumor immunotherapies through the induction of a specific immune response against cancer cells. However, despite promising preliminary data, none of these candidates have reached the clinic. Our hypothesis is that the carbohydrates on the vaccines may not survive antigen processing, and so more stable versions of these materials are required to create viable vaccines.
Our approach is to incorporate TACAs lacking the labile glycosidic bond: acetal-free carbohydrates (AFCs). This project aims to remove the unstable acetal functional group to yield a more robust carbohydrate structure that can then be incorporated into a vaccine candidate. In this presentation, two synthetic pathways will be described: conversion of a carbohydrate to a carbasugar through a rearrangement, and de novo synthesis from noncarbohydrate materials
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