93 research outputs found
Urban and Community Forests of the North Central West Region
This report details how land cover and urbanization vary within the states of Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota by community (incorporated and census designated places), county subdivision, and county. Specifically this report provides critical urban and community forestry information for each state including human population characteristics and trends, changes in urban and community lands, tree canopy and impervious surface cover characteristics, distribution of land-cover classes, a relative comparison of urban and community forests among local government types, determination of priority areas for tree planting, and a summary of urban tree benefits. Report information can improve the understanding, management, and planning of urban and community forests
Residential building energy conservation and avoided power plant emissions by urban and community trees in the United States
Urban trees and forests alter building energy use and associated emissions from power plants by shading buildings, cooling air temperatures and altering wind speeds around buildings. Field data on urban trees were combined with local urban/community tree and land cover maps, modeling of tree effects on building energy use and pollutant emissions, and state energy and pollutant costs to estimate tree effects on building energy use and associated pollutant emissions at the state to national level in the conterminous United States. Results reveal that trees and forests in urban/community areas in the conterminous United States annually reduce electricity use by 38.8 million MWh (3.1 billion) and avoid thousands of tonnes of emissions of several pollutants valued at $3.9 billion per year. Average reduction in national residential energy use due to trees is 7.2percent. Specific designs to reduce energy use using urban trees could increase these values and further reduce energy use and improve air quality in the United States
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Linking Urban Tree Cover Change and Local History in a Post-Industrial City
Municipal leaders are pursuing ambitious goals to increase urban tree canopy (UTC), but there is little understanding of the pace and socioecological drivers of UTC change. We analyzed land cover change in Philadelphia, Pennsylvania (United States) from 1970–2010 to examine the impacts of post-industrial processes on UTC. We interpreted land cover classes using aerial imagery and assessed historical context using archival newspapers, agency reports, and local historical scholarship. There was a citywide UTC increase of +4.3 percentage points. Substantial UTC gains occurred in protected open spaces related to both purposeful planting and unintentional forest emergence due to lack of maintenance, with the latter phenomenon well-documented in other cities located in forested biomes. Compared to developed lands, UTC was more persistent in protected open spaces. Some neighborhoods experienced substantial UTC gains, including quasi-suburban areas and depopulated low-income communities; the latter also experienced decreasing building cover. We identified key processes that drove UTC increases, and which imposed legacies on current UTC patterns: urban renewal, urban greening initiatives, quasi-suburban developments, and (dis)investments in parks. Our study demonstrates the socioecological dynamism of intra-city land cover changes at multi-decadal time scales and the crucial role of local historical context in the interpretation of UTC change
Five anthropogenic factors that will radically alter forest conditions and management needs in the Northern United States
The Northern United States includes the 20 states bounded by Maine, Maryland, Missouri, and Minnesota. With 70 million ha of forestland and 124 million people, it is the most densely forested (42% of land area) and most densely populated (74 people/km2) quadrant of the United States. Three recent, large-scale, multiresource assessments of forest conditions provide insight about trends and issues in the North, and collectively these and other supporting documents highlight factors that will be extraordinarily influential in large-scale northern forest management needs over the next 50 years. This review article discusses five of those factors: (1) northern forests lack age-class diversity and will uniformly grow old without management interventions or natural disturbances, (2) the area of forestland in the North will decrease as a consequence of expanding urban areas, (3) invasive species will alter forest density, diversity, and function, (4) management intensity for timber is low in northern forests and likely to remain so, and (5) management for nontimber objectives will gain relevance but will be challenging to implement. Suggested actions to address these factors include the following: develop quantifiable state and regional goals for forest diversity, understand the spatial and structural impacts of urban expansion on forests, develop symbiotic relationships among forest owners, forest managers, forest industry and the other stakeholders to support contemporary conservation goals, and work to understand the many dimensions of forest change. In the next several decades, climate change seems unlikely to overwhelm or negate any of the five factors discussed in this article; rather it will add another complicating dimension.Natural Resource Ecology and Managemen
Evaluating The National Land Cover Database Tree Canopy and Impervious Cover Estimates Across the Conterminous United States: A Comparison with Photo-Interpreted Estimates
The 2001 National Land Cover Database (NLCD) provides 30-m resolution estimates of percentage tree canopy and percentage impervious cover for the conterminous United States. Previous estimates that compared NLCD tree canopy and impervious cover estimates with photo-interpreted cover estimates within selected counties and places revealed that NLCD underestimates tree and impervious cover. Based on these previous results, a wall-to-wall comprehensive national analysis was conducted to determine if and how NLCD derived estimates of tree and impervious cover varies from photo-interpreted values across the conterminous United States. Results of this analysis reveal that NLCD significantly underestimates tree cover in 64 of the 65 zones used to create the NCLD cover maps, with a national average underestimation of 9.7% (standard error (SE) = 1.0%) and a maximum underestimation of 28.4% in mapping zone 3. Impervious cover was also underestimated in 44 zones with an average underestimation of 1.4% (SE = 0.4%) and a maximum underestimation of 5.7% in mapping zone 56. Understanding the degree of underestimation by mapping zone can lead to better estimates of tree and impervious cover and a better understanding of the potential limitations associated with NLCD cover estimates
Maternal DDT Exposures in Relation to Fetal and 5-Year Growth
Dichlorodiphenyltrichloroethane (DDT) is an organo-chlorine pesticide still used in areas of the world where malaria vector control is needed. Few studies have examined in utero exposures to DDT in relation to fetal and early childhood growth in populations with substantial exposure to DDT. Furthermore, only a portion of these studies have investigated in utero exposures and growth during childhood
The Astropy Problem
The Astropy Project (http://astropy.org) is, in its own words, "a community
effort to develop a single core package for Astronomy in Python and foster
interoperability between Python astronomy packages." For five years this
project has been managed, written, and operated as a grassroots,
self-organized, almost entirely volunteer effort while the software is used by
the majority of the astronomical community. Despite this, the project has
always been and remains to this day effectively unfunded. Further, contributors
receive little or no formal recognition for creating and supporting what is now
critical software. This paper explores the problem in detail, outlines possible
solutions to correct this, and presents a few suggestions on how to address the
sustainability of general purpose astronomical software
Self-Organization of the Escherichia coli Chemotaxis Network Imaged with Super-Resolution Light Microscopy
Photoactivated localization microscopy analysis of chemotaxis receptors in bacteria suggests that the non-random organization of these proteins results from random self-assembly of clusters without direct cytoskeletal involvement or active transport
Identification and validation of N-acetyltransferase 2 as an insulin sensitivity gene
Journal ArticleDecreased insulin sensitivity, also referred to as insulin resistance (IR), is a fundamental abnormality in patients with type 2 diabetes and a risk factor for cardiovascular disease. While IR predisposition is heritable, the genetic basis remains largely unknown. The GENEticS of Insulin Sensitivity consortium conducted a genome-wide association study (GWAS) for direct measures of insulin sensitivity, such as euglycemic clamp or insulin suppression test, in 2,764 European individuals, with replication in an additional 2,860 individuals. The presence of a nonsynonymous variant of N-acetyltransferase 2 (NAT2) [rs1208 (803A>G, K268R)] was strongly associated with decreased insulin sensitivity that was independent of BMI. The rs1208 "A" allele was nominally associated with IR-related traits, including increased fasting glucose, hemoglobin A1C, total and LDL cholesterol, triglycerides, and coronary artery disease. NAT2 acetylates arylamine and hydrazine drugs and carcinogens, but predicted acetylator NAT2 phenotypes were not associated with insulin sensitivity. In a murine adipocyte cell line, silencing of NAT2 ortholog Nat1 decreased insulin-mediated glucose uptake, increased basal and isoproterenol- stimulated lipolysis, and decreased adipocyte differentiation, while Nat1 overexpression produced opposite effects. Nat1-deficient mice had elevations in fasting blood glucose, insulin, and triglycerides and decreased insulin sensitivity, as measured by glucose and insulin tolerance tests, with intermediate effects in Nat1 heterozygote mice. Our results support a role for NAT2 in insulin sensitivity
Abnormal Intracellular Accumulation and Extracellular Aβ Deposition in Idiopathic and Dup15q11.2-q13 Autism Spectrum Disorders
<div><h3>Background</h3><p>It has been shown that amyloid ß (Aβ), a product of proteolytic cleavage of the amyloid β precursor protein (APP), accumulates in neuronal cytoplasm in non-affected individuals in a cell type–specific amount.</p> <h3>Methodology/Principal Findings</h3><p>In the present study, we found that the percentage of amyloid-positive neurons increases in subjects diagnosed with idiopathic autism and subjects diagnosed with duplication 15q11.2-q13 (dup15) and autism spectrum disorder (ASD). In spite of interindividual differences within each examined group, levels of intraneuronal Aβ load were significantly greater in the dup(15) autism group than in either the control or the idiopathic autism group in 11 of 12 examined regions (p<0.0001 for all comparisons; Kruskall-Wallis test). In eight regions, intraneuronal Aβ load differed significantly between idiopathic autism and control groups (p<0.0001). The intraneuronal Aβ was mainly N-terminally truncated. Increased intraneuronal accumulation of Aβ<sub>17–40/42</sub> in children and adults suggests a life-long enhancement of APP processing with α-secretase in autistic subjects. Aβ accumulation in neuronal endosomes, autophagic vacuoles, Lamp1-positive lysosomes and lipofuscin, as revealed by confocal microscopy, indicates that products of enhanced α-secretase processing accumulate in organelles involved in proteolysis and storage of metabolic remnants. Diffuse plaques containing Aβ<sub>1–40/42</sub> detected in three subjects with ASD, 39 to 52 years of age, suggest that there is an age-associated risk of alterations of APP processing with an intraneuronal accumulation of a short form of Aβ and an extracellular deposition of full-length Aβ in nonfibrillar plaques.</p> <h3>Conclusions/Significance</h3><p>The higher prevalence of excessive Aβ accumulation in neurons in individuals with early onset of intractable seizures, and with a high risk of sudden unexpected death in epilepsy in autistic subjects with dup(15) compared to subjects with idiopathic ASD, supports the concept of mechanistic and functional links between autism, epilepsy and alterations of APP processing leading to neuronal and astrocytic Aβ accumulation and diffuse plaque formation.</p> </div
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