639 research outputs found
US 30 at SR 101 J-Turn: A Safety Driven Solution
So you want to build a J-turn? See how the need for a safety improvement led to the construction of an alternative intersection. From the early stages of project selection and development to design and construction, take an inside look at Indiana’s newest J-turn, US 30 at SR 101 in the Fort Wayne District
Local Employment Growth, Migration, and Public Land Policy: Evidence from the Northwest Forest Plan
Debates over protecting public land reveal two views. Some argue protection reduces commodity production, reducing local employment and increasing out-migration. Others contend protection produces amenities that support job growth and attract migrants. We test these competing views for the Northwest Forest Plan (NWFP), which reallocated 11 million acres of federal land from timber production to protecting old-growth forest species. We find evidence that land protection directly reduced local employment growth and increased net migration. The total negative effect on employment was offset only slightly by positive migration-driven effects. Employment losses were concentrated in metropolitan counties, but percentage losses were higher in rural counties.amenities, employment growth, migration, Northwest Forest Plan, oldgrowth forests, public land management, Community/Rural/Urban Development, Land Economics/Use,
The Association of Water Quality Parameters, Geological Substrates and Periphyton Community Structure
This research was designed to understand the structure of epilithic diatom assemblage of a first-to-third order stream system which has minimal variance in nutrient concentration, but significant differences in geomorphological character. The primary objective was to determine the importance of geological substrate on the structure of the diatom assemblages. The second objective was to examine the effect of flow on these assemblages, and the third part of the research was to develop a seasonal model of temporal and spatial annual succession. The temporal and spatial models represent the effect of seasons, stream order, substrate characteristics, storm events, and periods of lesser flow on diatom assemblages. Also, a compilation of the diatoms reported in the Ozark Highlands is included along with a determination of the similarity of the diatom flora in the study reach on the Middle Fork of the White River and other regional streams
The Extended and Eccentric E-DNA Structure Induced by Cytosine Methylation or Bromination
Cytosine methylation or bromination of the DNA sequence d(GGCGCC)2 is shown here to induce a novel extended and eccentric double helix, which we call E-DNA. Like B-DNA, E-DNA has a long helical rise and bases perpendicular to the helix axis. However, the 3′-endo sugar conformation gives the characteristic deep major groove and shallow minor groove of A-DNA. Also, if allowed to crystallize for a period of time longer than that yielding E-DNA, the methylated sequence forms standard A-DNA, suggesting that E-DNA is a kinetically trapped intermediate in the transition to A-DNA. Thus, the structures presented here chart a crystallographic pathway from B-DNA to A-DNA through the E-DNA intermediate in a single sequence. The E-DNA surface is highly accessible to solvent, with waters in the major groove sitting on exposed faces of the stacked nucleotides. We suggest that the geometry of the waters and the stacked base pairs would promote the spontaneous deamination of 5-methylcytosine in the transition mutation of dm5C-dG to dT-dA base pairs
Reviewing and exploring the qualitative impacts that different market and regulatory measures can have on encouraging energy communities based on their organizational structure
The emergence of energy communities represents a promising option to democratize the energy system by empowering consumers to take a more active role. This can aid in achieving energy and environmental goals as well as encouraging more equitable distribution of costs and revenues between all parties on the energy system. Despite this potential, energy communities are still a nascent solution, the success of which is heavily influenced by regulations. As a result, there are a wide variety of organizational structures for energy communities at this time. This paper provides a review of the policy landscape in Spain as it relates to energy communities. This work also presents a formalized method for characterizing different energy community structures and provides a qualitative assessment of the impacts of different measures to encourage energy communities with respect to their organizational structure. Findings suggest that many market-focused measures, including wholesale, local flexibility, capacity, and multisector market measures favor larger, more integrated communities, while regulatory, legal, and organizational measures, including peer-to-peer trading, aggregation, and self-consumption favor smaller, more distributed communities. Additionally, when developing policies to encourage the growth of energy communities, policymakers should be cognizant of the progression of policies in the context of the desired outcomes for energy community growth specific to the region or country and its goals.Peer ReviewedPostprint (published version
The Holliday Junction in an Inverted Repeat DNA Sequence: Sequence Effects on the Structure of Four-way Junctions
Holliday junctions are important structural intermediates in recombination, viral integration, and DNA repair. We present here the single-crystal structure of the inverted repeat sequence d(CCGGTACCGG) as a Holliday junction at the nominal resolution of 2.1 Å. Unlike the previous crystal structures, this DNA junction has B-DNA arms with all standard Watson–Crick base pairs; it therefore represents the intermediate proposed by Holliday as being involved in homologous recombination. The junction is in the stacked-X conformation, with two interconnected duplexes formed by coaxially stacked arms, and is crossed at an angle of 41.4° as a right-handed X. A sequence comparison with previous B-DNA and junction crystal structures shows that an ACC trinucleotide forms the core of a stable junction in this system. The 3*-CzG base pair of this ACC core forms direct and water-mediated hydrogen bonds to the phosphates at the crossover strands. Interactions within this core define the conformation of the Holliday junction, including the angle relating the stacked duplexes and how the base pairs are stacked in the stable form of the junction
Blistering Failure of Elastic Coatings with Applications to Corrosion Resistance
A variety of polymeric surfaces, such as anti-corrosion coatings and
polymer-modified asphalts, are prone to blistering when exposed to moisture and
air. As water and oxygen diffuse through the material, dissolved species are
produced, which generate osmotic pressure that deforms and debonds the
coating.These mechanisms are experimentally well-supported; however,
comprehensive macroscopic models capable of predicting the formation osmotic
blisters, without extensive data-fitting, is scant. Here, we develop a general
mathematical theory of blistering and apply it to the failure of anti-corrosion
coatings on carbon steel. The model is able to predict the irreversible,
nonlinear blister growth dynamics, which eventually reaches a stable state,
ruptures, or undergoes runaway delamination, depending on the mechanical and
adhesion properties of the coating. For runaway delamination, the theory
predicts a critical delamination length, beyond which unstable corrosion-driven
growth occurs. The model is able to fit multiple sets of blister growth data
with no fitting parameters. Corrosion experiments are also performed to observe
undercoat rusting on carbon steel, which yielded trends comparable with model
predictions. The theory is used to define three dimensionless numbers which can
be used for engineering design of elastic coatings capable of resisting visible
deformation, rupture, and delamination.Comment: 29 pages, 11 figures, submitted to Electrochimica Acta (under review
A Migração Internacional Na Amazônia Brasileira
The main goal of this article is to evaluate the international in-migration in the Brazilian Amazon, focusing on the migrants born in the countries located next to the Amazon borders, like Peru, Bolívia, Colômbia and Paraguai. The idea is to analyze these migrants in terms of age, level of study, income, gender and occupation at destination, as well as the period of arrival to Brazil. The localization patterns of these migrants are also showed, if they are living in municipalities next to the borders, next to big cities, state capitals or not. In order to do this, data from the Brazilian Demographic Census of 2000 and from the Population Enumeration of 2007 are used.Este trabalho tem como objetivo principal apresentar uma avaliação da imigração internacional na Amazônia brasileira, dando especial ênfase aos migrantes provenientes de países que fazem fronteira com a Amazônia, como Peru, Bolívia, Colômbia e Paraguai. A ideia é analisar estes migrantes, comparando informações de idade, nível de escolaridade e de renda, sexo e ocupação no destino, assim como o período em que chegaram ao país. Também é mostrado o padrão de localização destes migrantes, se residem em municípios perto da fronteira, de grandes cidades, capitais estaduais ou não. Para isto, são utilizados dados do Censo Demográfico de 2000 e da Contagem Populacional de 2007 para uma análise bem atual
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Northwest forest plan effects on county net migration and employment growth : causality of policy variables, timing of response, relevant time periods, rural vs. metro policy effects and effects on industry employment
County-level net migration and employment growth rates associated with the Northwest Forest Plan (NWFP) are examined. The NWFP area encompasses federal land in 53 Oregon, Washington and California counties; 20 counties adjacent to NWFP counties are also included in the sample. The NWFP was enacted in December of 1993, however, this analysis examines the 24 year time period from 1980 through 2003. Net migration (the change in population due to in-migration and out-migration) and employment growth are represented by a simultaneous equation model (SEM) that is corrected for spatial autocorrelation. While the NWFP land allocations are expected to influence net migration and employment growth, they are potentially determined by similar processes as the endogenous economic indicators. Logistic regression analysis shows the probability that NWFP lands were allocated to biodiversity purposes or to land uses subject to timber harvest depends on natural, political and economic variables. The SEM is run on a yearly basis to explore changes in net migration and employment growth due to policy enactment, future expectations about land allocations, and market fluctuations. These results suggest the time period was characterized by many changes the endogenous variables from the effects of land management. In addition, the yearly analysis suggests that variation in yearly employment growth and net migration may not be sufficient for precise estimation of the effects of the exogenous variables. Pooling the yearly data over policy-relevant time periods is thus appropriate and provides insight into the NWFP effects on the economic indicators. Counties with more land reserved for biodiversity purposes had higher net migration and employment growth. In contrast, counties with more land allocated to extractive uses experienced low net migration. During the period following NWFP enactment, from 1994 to 2003, the classification of land according to NWFP management yields no significant relationship, suggesting adjustment to the NWFP had occurred. The effects of land management variables for rural and metropolitan counties are distinguished in another SEM. Contrary to the popular notion that employment effects were felt in large part by rural counties, this analysis shows changes in employment growth due to policy effects were felt primarily in metropolitan counties within the NWFP region. In addition, higher net migration occurred in rural and metropolitan counties containing land reserved for biodiversity purposes. These counties also experienced a simultaneous increase in employment growth as a result of allocation of these lands. Analysis of employment growth changes in specific industry sectors indicates manufacturing jobs were lost, however, service industry growth was encouraged as a result of NWFP land allocations. In addition, land allocated solely for the purpose of biodiversity services was not associated with changes in the manufacturing employment while potentially promoting growth in service sector employment
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