1,528 research outputs found
PERSISTENT POCKETS OF EXTREME AMERICAN POVERTY: PEOPLE OR PLACE BASED?
Over the past four decades almost 400 U.S. counties have persistently had poverty rates in excess of 20 percent. These counties are generally characterized by weak economies and disadvantaged populations. This raises the hotly debated question of whether poverty-reducing policies should be directed more at helping people or helping the places where they reside. Using a variety of regression approaches, including geographically weighted regression analysis, we consistently find that local job growth especially reduces poverty in persistent-poverty counties. We also find that persistent-poverty counties do not respond more sluggishly to exogenous shocks, nor do they experience more adverse spillover effects from their neighboring counties. Finally, we identify some key geographic differences in the poverty determining mechanism among persistent-poverty clusters. Taken together, these results indicate that place-based economic development has a potential role for reducing poverty in these counties.poverty, persistent poverty, economic development policies, place-based policies, Food Security and Poverty,
A Simplified, Closed-Form Method for Screening Spacecraft Orbital Heating Variations
A closed-form analytical technique has been developed to screen orbital average heating variations as a function of beta angle, altitude, surface area, and surface optical properties. Using planetary view factor equations for surfaces parallel-to and normal-to the local vertical, a cylindrical umbral shadow approximation, and a simplified albedo flux model, heating rate equations are formulated and then integrated to obtain orbital average heating. The results are compared to detailed analytical predictions using Monte Carlo integration and an assessment of error is presented
Spatial Concentration of American Poverty: Should We Care, and What Are the Options?
Partridge and Rickman explore the wide geographic disparities in poverty across the United States. Their focus on the spatial dimensions of U.S. poverty reveals distinct differences across states, metropolitan areas, and counties and leads them to consider why antipoverty policies have succeeded in some places and failed in others.https://research.upjohn.org/up_press/1012/thumbnail.jp
The Geography of American Poverty: Is There a Need for Place-Based Policies?
Partridge and Rickman explore the wide geographic disparities in poverty across the United States. Their focus on the spatial dimensions of U.S. poverty reveals distinct differences across states, metropolitan areas, and counties and leads them to consider why antipoverty policies have succeeded in some places and failed in others.https://research.upjohn.org/up_press/1012/thumbnail.jp
Design and Specifications for the Highland Regolith Prototype Simulants NU-LHT-1M and -2M
The first two prototype lunar regolith simulants were to replicate characteristics of the lunar highlands. A major change from initial plans was to use an estimate of typical Apollo 16 highland material rather than a specific core. This change was compatible with project objectives and necessitated by the lack of adequate data from a single core. To make the initial simulant, a crystalline component and a glass component were deemed necessary. Lithic feedstocks were obtained with the assistance of the Stillwater Mining Company. The mixing of the rock constituents was done based on normative mineralogy rather than modal mineralogy. This was done to simplify development. A major design decision was not to attempt simulation of the range of glass chemistries observed in Apollo samples. A single glass was assumed to be adequate for engineering purposes for which the simulant would be used. Glass was made in a process developed at Zybek Advanced Products of Boulder, Colorado. Mill sand was used as the feedstock for this process. A second generation of the simulant was made that incorporated the additional minerals apatite, synthetic whitlockite, and pyrite. The olivine source was changed to the commercially produced Twin Sisters Dunite, and a pseudo-agglutinate product was invented and added to the -2M product. The pseudo-agglutinate captures all of the lunar agglutinate features but does not attempt to incorporate nanophase Fe
An evaluation of the implementation of Georgia's Pre-k program: Report of the findings from the Georgia Early Childhood Study (2002-03)
After ten years, Georgia continues to lead the nation in providing full day, publicly subsidized Pre-K to four-year-olds whose parents choose to enroll them. In this report, we assess the extent to which differences in the way Pre-K is implemented affect children's development. Do teachers with higher levels of education have more positive impacts on children's development? Do teaching styles make a difference in terms of children's outcomes by the end of kindergarten? Do children taught using certain curricula fare better than those taught using others? Answers to questions such as these can assist Pre-K administrators in refining Georgia's program and inform those in other states who are developing or expanding their prekindergarten programs
Investment suitability and path dependency perpetuate inequity in international mitigation finance toward developing countries
Developed country pledges to provide finance to developing countries for their mitigation actions sit at the heart of international climate cooperation. Currently, climate finance largely flows to big and fast-growing developing countries while low-income and vulnerable countries are underserved. Here, using wind and solar project data, we highlight inequities in the distribution of international investments in mitigation across developing countries and explore the factors that influence public and private investment flows. Results show that public actors are influenced by domestic climate policies since the Paris Agreement, while private finance flows are shaped by investment suitability conditions, which restricts access to both types of finance in the poorest countries. Further, public and private flows are strongly shaped by path dependency, generating an āinvestment lock-inā that perpetuates distributional inequities. Future international commitments to direct climate finance should address distributional issues to meet countriesā needs and the goals of the Paris Agreement
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Combustion of carbon fines by above-bed recycle in an atmospheric fluidized bed burner
Fluidized bed combustion studies have resulted in the development of a burner with 99.98% carbon utilization efficiency. This was made possible partly by use of a fines burning modeling technique that predicts burning efficiencies as a function of process parameters. A shrinking sphere reaction model was used in conjunction with empirical combustion kinetics data, actual particle size distribution, and gas environment variables such as temperature, pressure, and composition to determine required recycle rates for complete combustion. The fines burning model was verified on a 0.40-m (16-in.) diameter atmospheric burner operated at 1.1-m/s (3.6-ft/s) superficial velocity at 900/sup 0/C (1650/sup 0/F). During a 50-h test, burn rates of over 60 kg/h (130 lb/h) were attained. Carbon fines generation amounted to over 30% of the feed (which was sized to -5 mm (-3/16 in.) ring size), but the final carbon inventory was less than 0.5 kg (1 lb) upon completion of the test. Fines recycle rates during the test averaged 7 kg/min (15 lb/min); the fines combustion model had predicted a required recycle rate of 8 kg/min (17 lb/min). This close correlation lends a good measure of credibility to the techniques used in analyzing fine carbon combustion characteristics. This technique was also used to analyze coal fines combustion by recycle to the fluid bed. Reasonable recycle rates are predicted for lower bed fines injection
Modeling of Dislocation Structures in Materials
A phenomenological model of the evolution of an ensemble of interacting
dislocations in an isotropic elastic medium is formulated. The line-defect
microstructure is described in terms of a spatially coarse-grained order
parameter, the dislocation density tensor. The tensor field satisfies a
conservation law that derives from the conservation of Burgers vector.
Dislocation motion is entirely dissipative and is assumed to be locally driven
by the minimization of plastic free energy. We first outline the method and
resulting equations of motion to linear order in the dislocation density
tensor, obtain various stationary solutions, and give their geometric
interpretation. The coupling of the dislocation density to an externally
imposed stress field is also addressed, as well as the impact of the field on
the stationary solutions.Comment: RevTeX, 19 pages. Also at http://www.scri.fsu.edu/~vinals/jeff1.p
Failure of conventional retrograde cystography to detect bladder ruptures in pelvic trauma
Conventional retrograde cystography is often used to investigate patients with suspected bladder ruptures in pelvic trauma. Clinical indicators suggestive of a rupture include haematuria and suprapubic tenderness and should increase the suspicion of bladder and urinary tract injury and prompt the clinician to undertake further investigations. Two patients with high-energy pelvic fractures had bladder ruptures detected intraoperatively despite normal preoperative retrograde cystogram. Both patients had significant clinical indicators suggestive of underlying bladder and urinary tract injury. In both cases, a routine conventional retrograde cystogram was performed but failed to identify the full extent of the bladder injury. A possible reason for misdiagnosis in these cases is the delay between injury and investigation due to tertiary referral of care
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