232 research outputs found
Commentary on “Critical Appraisal of Published Systematic Reviews Assessing the Cost-Effectiveness of Telemedicine Studies”
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140283/1/tmj.2014.9980.pd
Short Term Histological Changes in the Palatal Sutures and the Periodontal Ligaments Resulting from Rapid Palatal Expansion in the Rhesus Monkey
Septic regulations and suburban development patterns : an analysis based on soil data in Norfolk County, Massachusetts
Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2003.Includes bibliographical references (p. 95-98).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Urban sanitation systems are fundamental elements of modern urban development. Decentralized, privately operated, on-site wastewater disposal systems have also played an important role in suburban and exurban development over the past fifty years. This research is an attempt to assess the current influence of on-site wastewater disposal technology and regulations on land use patterns in Norfolk County, Massachusetts; to estimate the potential impacts of technological and regulatory change; and to assess the potential role of on-site sanitation policies in managing suburban and exurban development. I grouped soil types into seven interpretive classes based on their limitations for wastewater disposal; and created a Soil Development Index, which represents the relative proportion of soil classes in available and developed land over time. I found that soils with high groundwater and slow permeability are systematically underrepresented in residential development utilizing on-site wastewater disposal; comparisons to sewer service areas suggest these patterns may be due to regulatory restrictions on the use of septic systems. Slowly permeable soils and shallow bedrock areas are also associated with larger lot sizes in unsewered areas. The land-consumptive patterns of development observed in unsewered suburbs suggest that the current system of on-site sanitation is closely linked to other public policies that promote large-lot single family large-lot development to the exclusion of more diverse development models. The history of centralized and decentralized sanitation systems in the United States demonstrates that sanitation policies have evolved over time to address a wider variety of social and political concerns, including explicit planning objectives. Additional research is necessary to assess how sanitation policies -- including standards for on-site wastewater disposal -- might be used as implementation mechanisms for land use and planning policies intended to promote sustainabilityby Timothy W. Reardon.M.C.P
Tailoring community-based wellness initiatives with latent class analysis--Massachusetts Community Transformation Grant projects
INTRODUCTION: Community-based approaches to preventing chronic diseases are attractive because of their broad reach and low costs, and as such, are integral components of health care reform efforts. Implementing community-based initiatives across Massachusetts\u27 municipalities presents both programmatic and evaluation challenges. For effective delivery and evaluation of the interventions, establishing a community typology that groups similar municipalities provides a balanced and cost-effective approach.
METHODS: Through a series of key informant interviews and exploratory data analysis, we identified 55 municipal-level indicators of 6 domains for the typology analysis. The domains were health behaviors and health outcomes, housing and land use, transportation, retail environment, socioeconomics, and demographic composition. A latent class analysis was used to identify 10 groups of municipalities based on similar patterns of municipal-level indicators across the domains.
RESULTS: Our model with 10 latent classes yielded excellent classification certainty (relative entropy = .995, minimum class probability for any class = .871), and differentiated distinct groups of municipalities based on health-relevant needs and resources. The classes differentiated healthy and racially and ethnically diverse urban areas from cities with similar population densities and diversity but worse health outcomes, affluent communities from lower-income rural communities, and mature suburban areas from rapidly suburbanizing communities with different healthy-living challenges.
CONCLUSION: Latent class analysis is a tool that may aid in the planning, communication, and evaluation of community-based wellness initiatives such as Community Transformation Grants projects administrated by the Centers for Disease Control and Prevention
Unscreened water-diversion pipes pose an entrainment risk to the threatened green sturgeon, Acipenser medirostris.
Over 3,300 unscreened agricultural water diversion pipes line the levees and riverbanks of the Sacramento River (California) watershed, where the threatened Southern Distinct Population Segment of green sturgeon, Acipenser medirostris, spawn. The number of sturgeon drawn into (entrained) and killed by these pipes is greatly unknown. We examined avoidance behaviors and entrainment susceptibility of juvenile green sturgeon (35±0.6 cm mean fork length) to entrainment in a large (>500-kl) outdoor flume with a 0.46-m-diameter water-diversion pipe. Fish entrainment was generally high (range: 26-61%), likely due to a lack of avoidance behavior prior to entering inescapable inflow conditions. We estimated that up to 52% of green sturgeon could be entrained after passing within 1.5 m of an active water-diversion pipe three times. These data suggest that green sturgeon are vulnerable to unscreened water-diversion pipes, and that additional research is needed to determine the potential impacts of entrainment mortality on declining sturgeon populations. Data under various hydraulic conditions also suggest that entrainment-related mortality could be decreased by extracting water at lower diversion rates over longer periods of time, balancing agricultural needs with green sturgeon conservation
Serum Amyloid A Facilitates Early Lesion Development in \u3cem\u3eLdlr\u3csup\u3e-/-\u3c/sup\u3e\u3c/em\u3e Mice
BACKGROUND: Atherosclerosis is a chronic inflammatory disorder, and several studies have demonstrated a positive association between plasma serum amyloid A (SAA) levels and cardiovascular disease risk. The aim of the study was to examine whether SAA has a role in atherogenesis, the underlying basis of most cardiovascular disease.
METHODS AND RESULTS: Mice globally deficient in acute-phase isoforms Saa1 and Saa2 (Saa-/-) were crossed to Ldlr-/- mice (Saa-/-Ldlr-/-). Saa-/-Ldlr-/- mice demonstrated a 31% reduction in lesional area in the ascending aorta but not in the aortic root or innominate artery after consuming a high-fat, high-cholesterol Western-type diet for 6 weeks. The lesions were predominantly macrophage foam cells. The phenotype was lost in more mature lesions in mice fed a Western-type diet for 12 weeks, suggesting that SAA is involved in early lesion development. The decreased atherosclerosis in the Saa-/-Ldlr-/- mice occurred despite increased levels of blood monocytes and was independent of plasma lipid levels. SAA is produced predominantly by hepatocytes and macrophages. To determine which source of SAA may have a dominant role in lesion development, bone marrow transplantation was performed. Ldlr-/- mice that received bone marrow from Saa-/-Ldlr-/- mice had slightly reduced ascending aorta atherosclerosis compared with Saa-/-Ldlr-/- mice receiving bone marrow from Ldlr-/- mice, indicating that the expression of SAA by macrophages may have an important influence on atherogenesis.
CONCLUSIONS: The results indicate that SAA produced by macrophages promotes early lesion formation in the ascending aorta
Pulsar scintillation through thick and thin: Bow shocks, bubbles, and the broader interstellar medium
Observations of pulsar scintillation are among the few astrophysical probes of very small-scale (≲ au) phenomena in the interstellar medium (ISM). In particular, characterization of scintillation arcs, including their curvature and intensity distributions, can be related to interstellar turbulence and potentially overpressurized plasma in local ISM inhomogeneities, such as supernova remnants, H II regions, and bow shocks. Here we present a survey of eight pulsars conducted at the Five-hundred-metre Aperture Spherical Telescope (FAST), revealing a diverse range of scintillation arc characteristics at high sensitivity. These observations reveal more arcs than measured previously for our sample. At least nine arcs are observed toward B1929+10 at screen distances spanning ~90 per cent of the pulsar’s 361 pc path length to the observer. Four arcs are observed toward B0355+54, with one arc yielding a screen distance as close as ∼105 au (<1 pc) from either the pulsar or the observer. Several pulsars show highly truncated, low-curvature arcs that may be attributable to scattering near the pulsar. The scattering screen constraints are synthesized with continuum maps of the local ISM and other well-characterized pulsar scintillation arcs, yielding a three-dimensional view of the scattering media in context
A mathematical model for human nucleotide excision repair: Damage recognition by random order assembly and kinetic proofreading
A mathematical model of human nucleotide excision repair was constructed and validated. The model incorporates cooperative damage recognition by RPA, XPA, and XPC followed by three kinetic proofreading steps by the TFIIH transcription/repair factor. The model yields results consistent with experimental data regarding excision rates of UV photoproducts by the reconstituted human excision nuclease system as well as the excision of oligonucleotides from undamaged DNA. The model predicts the effect that changes in the initial concentrations of repair factors have on the excision rate of damaged DNA and provides a testable hypothesis on the bio-chemical mechanism of cooperativity in protein assembly, suggesting experiments to determine if cooperativity in protein assembly results from an increased association rate or a decreased dissociation rate. Finally, a comparison between the random order assembly with kinetic proofreading model and a sequential assembly model is made. This investigation reveals the advantages of the random order assembly/kinetic proofreading model
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