11,351 research outputs found
The comprehension revolution : a twenty-year history of process and practice related to reading comprehension
Includes bibliographie
Out of Sight, Out of Mind: Including Group Quarters Residents with Household Residents Can Change What We Know About Working-Age People with Disabilities
Information about residents of institutional and noninstitutional group quarters (GQ), particularly those with disabilities, has been limited by gaps in survey data, and statistics based on data that exclude some or all GQ residents are biased as estimates of total population statistics. We used the 2006 and 2007 American Community Survey (ACS) to identify the distribution of working-age populations with and without disabilities by major residence type, and to assess the sensitivity of disability statistics to GQ residence. Our findings showed that (1) of those with disabilities, about one in 13 males and one in 33 females live in GQ; (2) younger males with disabilities are more likely to reside there, particularly at institutional GQ; (3) individuals with and without disabilities who are black, American Indian, never married, or have less than a high school education had higher GQ residence rates; (4) 40% of male and 62% of female GQ residents have a disability; (5) adding GQ residents to household residents increases estimated disability prevalence for males by 6% and the estimated difference between disability prevalence rates by gender nearly disappears; and (6) inclusion of the GQ population substantively lowers employment rate estimates for males with disabilities—especially young blacks and American Indians
Beyond Binomial and Negative Binomial: Adaptation in Bernoulli Parameter Estimation
Estimating the parameter of a Bernoulli process arises in many applications,
including photon-efficient active imaging where each illumination period is
regarded as a single Bernoulli trial. Motivated by acquisition efficiency when
multiple Bernoulli processes are of interest, we formulate the allocation of
trials under a constraint on the mean as an optimal resource allocation
problem. An oracle-aided trial allocation demonstrates that there can be a
significant advantage from varying the allocation for different processes and
inspires a simple trial allocation gain quantity. Motivated by realizing this
gain without an oracle, we present a trellis-based framework for representing
and optimizing stopping rules. Considering the convenient case of Beta priors,
three implementable stopping rules with similar performances are explored, and
the simplest of these is shown to asymptotically achieve the oracle-aided trial
allocation. These approaches are further extended to estimating functions of a
Bernoulli parameter. In simulations inspired by realistic active imaging
scenarios, we demonstrate significant mean-squared error improvements: up to
4.36 dB for the estimation of p and up to 1.80 dB for the estimation of log p.Comment: 13 pages, 16 figure
INTERREGIONAL EFFECTS OF REDUCED TIMBER HARVESTS: THE IMPACT OF THE NORTHERN SPOTTED OWL LISTING IN RURAL AND URBAN OREGON
A core-periphery, multiregional, input-output model of western Oregon is used to estimate impacts of periphery timber harvest reductions resulting from listing of an endangered species. Under the most probable scenario, 31,620 total jobs would be lost in the two regions. Fourteen percent of this impact is absorbed in the core (Metro) region. Forty percent of periphery and 80% of Metro jobs lost are from service sectors, a result of important core-periphery trade in central place services. Explicit inclusion of unemployment benefits for displaced workers reduces employment loss estimates by 12% to 14%.Resource /Energy Economics and Policy,
THE ROLE OF AGRICULTURE IN OREGON'S ECONOMIC BASE: FINDINGS FROM A SOCIAL ACCOUNTING MATRIX
Most studies of a state’'s economic base count as “"basic”" only the “"traditional"” exports of goods, federal spending, and business investment. “"Nontraditional”" elements of the economic base (including exports of services, federal transfers to state/local governments and households, and extraregional property income) are typically ignored. We construct a social accounting matrix (SAM) for Oregon and estimate Oregon’'s economic base accounting for both traditional and nontraditional elements. Almost 20% of Oregon’'s jobs depend on extraregional income to households (including government transfers and outside property income), 11% depend on lumber and wood and paper products, and 8% depend on agriculture.Agribusiness,
Digestion of Protein in Premature and Term Infants.
Premature birth rates and premature infant morbidity remain discouragingly high. Improving nourishment for these infants is the key for accelerating their development and decreasing disease risk. Dietary protein is essential for growth and development of infants. Studies on protein nourishment for premature infants have focused on protein requirements for catch-up growth, nitrogen balance, and digestive protease concentrations and activities. However, little is known about the processes and products of protein digestion in the premature infant. This review briefly summarizes the protein requirements of term and preterm infants, and the protein content of milk from women delivering preterm and at term. An in-depth review is presented of the current knowledge of term and preterm infant dietary protein digestion, including human milk protease and anti-protease concentrations; neonatal intestinal pH, and enzyme activities and concentrations; and protein fermentation by intestinal bacteria. The advantages and disadvantages of incomplete protein digestion as well as factors that increase resistance to proteolysis of particular proteins are discussed. In order to better understand protein digestion in preterm and term infants, future studies should examine protein and peptide fragment products of digestion in saliva, gastric, intestinal and fecal samples, as well as the effects of the gut micro biome on protein degradation. The confluence of new mass spectrometry technology and new bioinformatics programs will now allow thorough identification of the array of peptides produced in the infant as they are digested
Streaming Video over HTTP with Consistent Quality
In conventional HTTP-based adaptive streaming (HAS), a video source is
encoded at multiple levels of constant bitrate representations, and a client
makes its representation selections according to the measured network
bandwidth. While greatly simplifying adaptation to the varying network
conditions, this strategy is not the best for optimizing the video quality
experienced by end users. Quality fluctuation can be reduced if the natural
variability of video content is taken into consideration. In this work, we
study the design of a client rate adaptation algorithm to yield consistent
video quality. We assume that clients have visibility into incoming video
within a finite horizon. We also take advantage of the client-side video
buffer, by using it as a breathing room for not only network bandwidth
variability, but also video bitrate variability. The challenge, however, lies
in how to balance these two variabilities to yield consistent video quality
without risking a buffer underrun. We propose an optimization solution that
uses an online algorithm to adapt the video bitrate step-by-step, while
applying dynamic programming at each step. We incorporate our solution into
PANDA -- a practical rate adaptation algorithm designed for HAS deployment at
scale.Comment: Refined version submitted to ACM Multimedia Systems Conference
(MMSys), 201
Optimizing baryon acoustic oscillation surveys – I. Testing the concordance ΛCDM cosmology
We optimize the design of future spectroscopic redshift surveys for
constraining the dark energy via precision measurements of the baryon acoustic
oscillations (BAO), with particular emphasis on the design of the Wide-Field
Multi-Object Spectrograph (WFMOS). We develop a model that predicts the number
density of possible target galaxies as a function of exposure time and
redshift. We use this number counts model together with fitting formulae for
the accuracy of the BAO measurements to determine the effectiveness of
different surveys and instrument designs. We search through the available
survey parameter space to find the optimal survey with respect to the dark
energy equation-of-state parameters according to the Dark Energy Task Force
Figure-of-Merit, including predictions of future measurements from the Planck
satellite. We optimize the survey to test the LambdaCDM model, assuming that
galaxies are pre-selected using photometric redshifts to have a constant number
density with redshift, and using a non-linear cut-off for the matter power
spectrum that evolves with redshift. We find that line-emission galaxies are
strongly preferred as targets over continuum emission galaxies. The optimal
survey covers a redshift range 0.8 < z < 1.4, over the widest possible area
(6000 sq. degs from 1500 hours observing time). The most efficient number of
fibres for the spectrograph is 2,000, and the survey performance continues to
improve with the addition of extra fibres until a plateau is reached at 10,000
fibres. The optimal point in the survey parameter space is not highly peaked
and is not significantly affected by including constraints from upcoming
supernovae surveys and other BAO experiments.Comment: 15 pages, 9 figure
Comparison of forest attributes derived from two terrestrial lidar systems.
Abstract
Terrestrial lidar (TLS) is an emerging technology for deriving forest attributes, including conventional inventory and canopy characterizations. However, little is known about the influence of scanner specifications on derived forest parameters. We compared two TLS systems at two sites in British Columbia. Common scanning benchmarks and identical algorithms were used to obtain estimates of tree diameter, position, and canopy characteristics. Visualization of range images and point clouds showed clear differences, even though both scanners were relatively high-resolution instruments. These translated into quantifiable differences in impulse penetration, characterization of stems and crowns far from the scan location, and gap fraction. Differences between scanners in estimates of effective plant area index were greater than differences between sites. Both scanners provided a detailed digital model of forest structure, and gross structural characterizations (including crown dimensions and position) were relatively robust; but comparison of canopy density metrics may require consideration of scanner attributes
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