1,593 research outputs found
Assessing An Economics Programme: Hansen Proficiencies, ePortfolio, and Undergraduate Research
Numerous sources calling for more accountability in higher education are putting increased pressure on many economics departments to develop assessment plans. This paper discusses a set of principles for programmatic assessment gleaned from the assessment literature, while highlighting one US economic department's journey to develop an assessment of student learning outcomes based on Hansen's proficiencies. We explain the curriculum reforms that culminate with independent undergraduate research as suggested by the highest level of Hansen's proficiencies. We describe ePortfolios which showcase student abilities and integrate evidence of student learning across the curriculum. For departments without direct guidance from accreditation boards or other agencies, we put forth a process of forming programmatic assessment in economics.
Security of Tenure and Land Registration in Africa: Literature Review and Synthesis
In 1984, the Land Tenure Center embarked on a project to evaluate the experiences with land registration and tenure reform in Africa. The goal was to determine is African states been able to use tenure reform and land registration to provide greater security of tenure than was available through customary tenure systems. Donor agencies focused attention on the creation of individual freehold title, emphasizing the heightened security of holding, marketability, and access to credit under such tenure. National governments, on the other hand, were more concerned to see that land was used productively rather than merely accumulated for purposes of prestige or inheritance or as a hedge against inflation, and for this reason have tended to favor granting more circumscribed rights, such as leaseholds or rights of occupancy. This literature review and synthesis was prepared as part of an effort to increase very substantially our knowledge, especially on a quantitative level, of tenure and development relationships in Africa. The literature review is an attempt to gather in one place data about the diverse efforts at land registration and to describe briefly for each country the various registration programs that have taken place (if any), why they were undertaken, and what subsequent studies of these programs have found. Among other things, it will be seen that the intended benefits, and beneficiaries, of land registration have changed over the century or so since the first systems were put in place. In addition to these variations over time, there are also differences among Anglophone, Francophone, and Lusophone countries, differences that not only influenced the structure of registration systems established during the colonial era, but also continue to inform the kinds of registration systems adopted today.Land Economics/Use,
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Human Visual Search as a Deep Reinforcement Learning Solution to a POMDP
When people search for a target in a novel image they oftenmake use of eye movements to bring the relatively high acuityfovea to bear on areas of interest. The strategies that controlthese eye movements for visual search have been of substantialscientific interest. In the current article we report a new com-putational model that shows how strategies for visual searchare an emergent consequence of perceptual/motor constraintsand approximately optimal strategies. The model solves a Par-tially Observable Markov Decision Process (POMDP) usingdeep Q-learning to acquire strategies that optimise the trade-off between speed and accuracy. Results are reported for theDistractor-ratio task
Competitive Wrestling-related Injuries in School Aged Athletes in U.S. Emergency Departments
Objective: To describe the characteristics of wrestling injuries occurring in male athletes aged 7-17 treated in United States (U.S.) emergency departments (ED) from 2000-2006, and to compare injury patterns between younger & older youth wrestlers.Methods: A stratified probability sample of U.S. hospitals providing emergency services in the National Electronic Injury Surveillance System was used for 2000-2006. ED visits for injuries sustained in organized wrestling were analyzed for male patients ages 7-17 years old (subdivided into 7-11 years old [youth group] and 12-17 years old [scholastic group]).Results: During the study period, there were an estimated 167,606 ED visits for wrestling injuries in 7-17 years old U.S. males, with 152,710 (91.1%) occurring in the older (12-17 years old) group. The annual injury incidence was 6.49 injuries/1,000 wrestlers in the youth group and 29.57 injuries/1,000 wrestlers in the scholastic group. The distribution of diagnoses was similar in both age groups, with sprain/strain as the most common diagnosis, followed by fracture and contusion/abrasion. Distributions of injury by location were significantly different between groups (p=0.02), although both groups exhibited approximately 75% of all injuries from the waist up. Overexertion and struck by/against were the most common precipitating and direct mechanisms in both groups, respectively. Over 97% of all injured wrestlers were treated and released.Conclusion: The types of injury in youth (7-11 years old) wrestlers are similar to those of scholastic (12-17 years old) wrestlers, although the distribution of body parts injured differs between the age groups. The majority of injuries occurs above the waist and may be a target for prevention strategies. [West J Emerg Med. 2010; 11(5):442-449.
Characterization of X-Linked SNP genotypic variation in globally distributed human populations
An analysis of X-linked genetic variation in human populations provides insights into population structure and demographic patterns
Photometric redshifts and quasar probabilities from a single, data-driven generative model
We describe a technique for simultaneously classifying and estimating the
redshift of quasars. It can separate quasars from stars in arbitrary redshift
ranges, estimate full posterior distribution functions for the redshift, and
naturally incorporate flux uncertainties, missing data, and multi-wavelength
photometry. We build models of quasars in flux-redshift space by applying the
extreme deconvolution technique to estimate the underlying density. By
integrating this density over redshift one can obtain quasar flux-densities in
different redshift ranges. This approach allows for efficient, consistent, and
fast classification and photometric redshift estimation. This is achieved by
combining the speed obtained by choosing simple analytical forms as the basis
of our density model with the flexibility of non-parametric models through the
use of many simple components with many parameters. We show that this technique
is competitive with the best photometric quasar classification
techniques---which are limited to fixed, broad redshift ranges and high
signal-to-noise ratio data---and with the best photometric redshift techniques
when applied to broadband optical data. We demonstrate that the inclusion of UV
and NIR data significantly improves photometric quasar--star separation and
essentially resolves all of the redshift degeneracies for quasars inherent to
the ugriz filter system, even when included data have a low signal-to-noise
ratio. For quasars spectroscopically confirmed by the SDSS 84 and 97 percent of
the objects with GALEX UV and UKIDSS NIR data have photometric redshifts within
0.1 and 0.3, respectively, of the spectroscopic redshift; this amounts to about
a factor of three improvement over ugriz-only photometric redshifts. Our code
to calculate quasar probabilities and redshift probability distributions is
publicly available
The role of nω-nitro-L-arginine in modulation of pulmonary vascular tone in the maturing newborn pig
AbstractCurrent therapeutic modalities for treatment of newborn pulmonary hypertensive crisis include but are not limited to the administration of nitric oxide (endothelium-derived relaxing factor). However, few data are available on the role of endogenously produced endothelium-derived relaxing factor in the modulation of pulmonary vascular tone in the neonate. In the current study, we investigated the acute effects of Nω-nitro- L -arginine (a potent competitive inhibitor of endothelium-derived relaxing factor synthase) on the pulmonary vasculature of anesthetized open-chest 48-hour-old ( n = 8) and 2-week-old ( n = 7) Yorkshire pigs. After baseline data were acquired, all animals received a 10 mg/kg per minute infusion of Nω-nitro- L -arginine for 10 minutes. To discern distal and proximal pulmonary arterial vessel changes, input mean and characteristic impedance were respectively determined. Pulmonary vascular resistance was also calculated (units determined in dyne • sec • cm -5 plus or minus the standard errorof the mean). Results showed Nω-nitro- L -arginine infusion did not significantly alter baseline pulmonary arterial pressure (22,370 ±1473 dyne/cm2 ), pulmonary vascular resistance (5171 ±805 dyne • sec • cm -5 ), input impedance (6343 ±806 dyne • sec • cm -5 ), or characteristic impedance (2073 ±418 dyne • sec • cm -5 ) in 48-hour-old pigs. In 2-week-old pigs, infusion of Nω-nitro- L -arginine elevated pulmonary arterial pressure (18,162 ±1415 dyne/cm 2 versus 23,838 ±1810 dyne/cm 2 , p = 0.015), pulmonary vascular resistance (810 ±137 dyne • sec • cm -5 versus 1519 dyne • sec • cm -5 , p = 0.030), and input impedance (2302 ±251 dyne • sec • cm -5 versus 2900 ±255 dyne • sec • cm -5 , p = 0.018). Characteristic impedance was not altered in 2-week-old pigs. These data indicate that Nω-nitro- L -arginine infusion resulted in pulmonary arteriolar vasoconstriction in 2-week-old pigs, but not in 48-hour-old pigs. This finding suggests that endothelium-derived relaxing factor does not modulate basal pulmonary arteriolar tone during the early newborn period, but does play a significant role in 2-week-old pigs. These data also suggest that the functional role for endothelium-derived relaxing factor is confined to the distal arteriolar pulmonary bed and does not extend to the larger proximal arterial vessels. (J THORAC CARDIOVASC SURG 1995;110:1486-92
Functional analysis of transcription factor binding sites in human promoters
BACKGROUND: The binding of transcription factors to specific locations in the genome is integral to the orchestration of transcriptional regulation in cells. To characterize transcription factor binding site function on a large scale, we predicted and mutagenized 455 binding sites in human promoters. We carried out functional tests on these sites in four different immortalized human cell lines using transient transfections with a luciferase reporter assay, primarily for the transcription factors CTCF, GABP, GATA2, E2F, STAT, and YY1.
RESULTS: In each cell line, between 36% and 49% of binding sites made a functional contribution to the promoter activity; the overall rate for observing function in any of the cell lines was 70%. Transcription factor binding resulted in transcriptional repression in more than a third of functional sites. When compared with predicted binding sites whose function was not experimentally verified, the functional binding sites had higher conservation and were located closer to transcriptional start sites (TSSs). Among functional sites, repressive sites tended to be located further from TSSs than were activating sites. Our data provide significant insight into the functional characteristics of YY1 binding sites, most notably the detection of distinct activating and repressing classes of YY1 binding sites. Repressing sites were located closer to, and often overlapped with, translational start sites and presented a distinctive variation on the canonical YY1 binding motif.
CONCLUSIONS: The genomic properties that we found to associate with functional TF binding sites on promoters -- conservation, TSS proximity, motifs and their variations -- point the way to improved accuracy in future TFBS predictions
Shallow seismic reflection profile of the Meers fault, Comanche County, Oklahoma
This is the publisher's version, also available electronically from “http://onlinelibrary.wiley.com”.A high-resolution seismic-reflection survey was conducted across the Meers fault in Comanche County, Oklahoma, in an attempt to determine the shallow structure associated with the fault zone. A downhole .50-caliber rifle was used as the seismic-energy source. Two 100-Hz geophones were connected in series at each receiver station. A 1.22-m station spacing was used for both source and receiver. Field recording parameters were set to optimize seismic reflections in the 40–150 millisecond range. A pre-analog-to-digital low-cut filter (24 dB/octave rolloff with −3 dB point of 220 Hz) resulted in dominant frequencies in excess of 150 Hz. Several interpretable reflection events between 40 and 120 msec on the processed seismic section provide a clear picture of the shallow structure. Reverse faulting is evident not only at the scarp itself but also on both the upthrown (north) and downthrown (south) portions of the line. This suggests the fault zone extends at least 180 m in both directions (north and south) from the scarp itself. Recent movement appears only to have occurred along the major fault associated with the scarp. The northern portion of the seismic line is characterized by gentle folding, which is not present on the southern portion
Feral swine harming insular sea turtle reproduction: The origin, impacts, behavior and elimination of an invasive species
Feral swine are among the world\u27s most destructive invasive species wherever they are found, with translocations figuring prominently in their range expansions. In contrast, sea turtles are beloved species that are listed as threatened or endangered throughout the world and are the focus of intense conservation efforts. Nest predation by feral swine severely harms sea turtle reproduction in many locations around the world. Here we quantify and economically assess feral swine nest predation at North Island, South Carolina, an important loggerhead sea turtle nesting beach. Feral swine depredation of North Island sea turtle nests was first detected in 2005, with annual nest monitoring initiated in 2010 documenting nearly total losses to feral swine in 2010 and 2011. The cumulative valuation of annual losses for North Island from 2010 to 2016 ranged as high as $1,166,500. To improve nesting success, an integrated approach for eliminating feral swine was implemented in 2010 and greatly intensified in 2013 by adding federal experts. Removal efforts were challenging due to the island\u27s remoteness and impenetrable habitats, weather, hazards in accessing the island, and wariness of the animals, especially as their population diminished. Removal of the final 11 swine required efforts from 2014 to 2016. Nest predation was highly variable and provided another example of the significance of conditioning by feral swine to sea turtle nests on the consequent severity of nest predation. Even the final individual inflicted heavy losses before his removal. Genetic analyses of feral swine removed from North Island and the adjacent mainland revealed that the island\u27s population did not originate from the nearby mainland, meaning they were (illegally) introduced to the island
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