Analyzing Demand For Disposal And Recycling Services: A Systems Approach

Pricing municipal solid waste (MSW) services using a flat fee offers no incentive to conserve on disposal. This has prompted the use of unit pricing schemes, which should reduce disposal in accordance with demand theory and encourage alternatives such as recycling. Most studies estimate distinct demand equations for disposal and recycling, and none use a systems approach to simultaneous estimate them. To that end, this research estimates such a model, which also recognizes the endogeneity of policy variables. The results offer important policy insight and shed light on the effectiveness of unit pricing in reducing disposal and simultaneously encouraging recycling.

Suspect screening of maternal serum to identify new environmental chemical biomonitoring targets using liquid chromatography-quadrupole time-of-flight mass spectrometry.

The use and advantages of high-resolution mass spectrometry (MS) as a discovery tool for environmental chemical monitoring has been demonstrated for environmental samples but not for biological samples. We developed a method using liquid chromatography-quadrupole time-of-flight MS (LC-QTOF/MS) for discovery of previously unmeasured environmental chemicals in human serum. Using non-targeted data acquisition (full scan MS analysis) we were able to screen for environmental organic acids (EOAs) in 20 serum samples from second trimester pregnant women. We define EOAs as environmental organic compounds with at least one dissociable proton which are utilized in commerce. EOAs include environmental phenols, phthalate metabolites, perfluorinated compounds, phenolic metabolites of polybrominated diphenyl ethers and polychlorinated biphenyls, and acidic pesticides and/or predicted acidic pesticide metabolites. Our validated method used solid phase extraction, reversed-phase chromatography in a C18 column with gradient elution, electrospray ionization in negative polarity and automated tandem MS (MS/MS) data acquisition to maximize true positive rates. We identified "suspect EOAs" using Agilent MassHunter Qualitative Analysis software, to match chemical formulas generated from each sample run with molecular formulas in our unique database of 693 EOAs assembled from multiple environmental literature sources. We found potential matches for 282 (41%) of the EOAs in our database. Sixty-five of these suspect EOAs were detected in at least 75% of the samples; only 19 of these compounds are currently biomonitored in National Health and Nutrition Examination Survey. We confirmed two of three suspect EOAs by LC-QTOF/MS using a targeted method developed through LC-MS/MS, reporting the first confirmation of benzophenone-1 and bisphenol S in pregnant women's sera. Our suspect screening workflow provides an approach to comprehensively scan environmental chemical exposures in humans. This can provide a better source of exposure information to help improve exposure and risk evaluation of industrial chemicals

Cognitive Prompts Fail to Moderate the Impact of Stereotype Threat on Older Adults’ Training Performance

Using a sample of 131 adults aged 55 to 70 years, researchers employed a 2 x 2 between-subject design to investigate whether cognitive prompts would counteract the negative effect of stereotype threat on older adults’ training outcomes. As hypothesized, stereotype threat negatively affected training outcomes. Contrary to expectations, cognitive prompts also negatively affected training outcomes, worsening the negative impact of stereotype threat. Results are discussed within the framework of cognitive load theory

Discussion of the selection and use of teaching aids and standard materials in the lower school at Perkins School for the Blind

Thesis (Ed.M.)--Boston Universit

Structural basis of mitochondrial receptor binding and constriction by DRP1.

Mitochondrial inheritance, genome maintenance and metabolic adaptation depend on organelle fission by dynamin-related protein 1 (DRP1) and its mitochondrial receptors. DRP1 receptors include the paralogues mitochondrial dynamics proteins of 49 and 51 kDa (MID49 and MID51) and mitochondrial fission factor (MFF); however, the mechanisms by which these proteins recruit and regulate DRP1 are unknown. Here we present a cryo-electron microscopy structure of full-length human DRP1 co-assembled with MID49 and an analysis of structure- and disease-based mutations. We report that GTP induces a marked elongation and rotation of the GTPase domain, bundle-signalling element and connecting hinge loops of DRP1. In this conformation, a network of multivalent interactions promotes the polymerization of a linear DRP1 filament with MID49 or MID51. After co-assembly, GTP hydrolysis and exchange lead to MID receptor dissociation, filament shortening and curling of DRP1 oligomers into constricted and closed rings. Together, these views of full-length, receptor- and nucleotide-bound conformations reveal how DRP1 performs mechanical work through nucleotide-driven allostery

Design for validation: An approach to systems validation

Every complex system built is validated in some manner. Computer validation begins with review of the system design. As systems became too complicated for one person to review, validation began to rely on the application of adhoc methods by many individuals. As the cost of the changes mounted and the expense of failure increased, more organized procedures became essential. Attempts at devising and carrying out those procedures showed that validation is indeed a difficult technical problem. The successful transformation of the validation process into a systematic series of formally sound, integrated steps is necessary if the liability inherent in the future digita-system-based avionic and space systems is to be minimized. A suggested framework and timetable for the transformtion are presented. Basic working definitions of two pivotal ideas (validation and system life-cyle) are provided and show how the two concepts interact. Many examples are given of past and present validation activities by NASA and others. A conceptual framework is presented for the validation process. Finally, important areas are listed for ongoing development of the validation process at NASA Langley Research Center

Seroprevalence of Schmallenberg virus in the United Kingdom and Republic of Ireland: 2011-2013

Since its identification in late 2011, Schmallenberg virus (SBV) spread rapidly across Europe. Using archived samples from domestic ruminants collected between October 2011 and June 2013, the seroprevalence in the United Kingdom (UK) and Republic of Ireland (IE) was estimated using a serum neutralisation test. There was no significant difference (P > 0.05) in seroprevalence between sheep and cows suggesting that neither species is significantly more at risk of SBV infection in the UK. A single 2011 sample tested positive; the sample was taken in November from a cow in Wiltshire. There was a steady increase in overall seroprevalence during the first three quarters of 2012, which then more than doubled in quarter 4 (October–December), which may reflect a peak of vector activity. By the end of June 2013, overall seroprevalence was around 72%. However, although seroprevalence was over 50% in Wales and southern and central counties of England, it was below 50% in all other areas of the UK and IE. This suggests that there were still substantial numbers of animals at risk of infection in the latter half of 2013

Preoperative thromboxane A2/prostaglandin H2 receptor activity predicts early graft thrombosis

AbstractPurpose: This study was carried out to determine whether early failure of infrainguinal bypass grafts is associated with increased expression of platelet thromboxane A2/prostaglandin H2 (TXA2/PGH2) receptors. A prospective correlation of preoperative platelet TXA2/PGH2 receptor-mediated activity with lower extremity graft patency was sought. Methods: Twenty-five patients who underwent infrainguinal bypass surgery for limb salvage were studied at an inpatient academic tertiary referral center and Department of Veterans Affairs Medical Center. Outcome measures were primary graft patency rate at 3 months, platelet TXA2/PGH2 receptor activity by equilibrium binding with 125I-BOP, and aggregation to the TXA2-mimetic U46619. Results: Preoperative platelet TXA2/PGH2 receptor density was higher (Bmax, 3100 ± 1300 vs 1500 ± 1100 sites/platelet [mean ± SD]; p = 0.004) in the five patients who had graft thrombosis within 3 months. The EC50 for U46619 was lower (26 ± 6 nmol/L vs 57 ± 30 nmol/L; p < 0.05) in these patients as well, confirming the functional effect of the increased receptor density. Early graft thrombosis was more likely in patients with a platelet TXA2/PGH2 receptor density greater than 3000 sites/platelet (odds ratio, 76; 95% confidence interval, 3.9 to 1500) or an EC50 for U46619 less than 30 nmol/L (odds ratio, 16; 95% confidence interval, 1.4 to 180). Conclusions: Elevated platelet TXA2/PGH2 receptor levels and enhanced sensitivity of platelet aggregation to TXA2 predict early arterial graft thrombosis. Specific TXA2/PGH2 receptor antagonism may prevent one of the mechanisms that contributes to early graft occlusion. (J Vasc Surg 1998;27:317-28.

The μ Switch Region Tandem Repeats Are Important, but Not Required, for Antibody Class Switch Recombination

Class switch DNA recombinations change the constant (C) region of the antibody heavy (H) chain expressed by a B cell and thereby change the antibody effector function. Unusual tandemly repeated sequence elements located upstream of H chain gene exons have long been thought to be important in the targeting and/or mechanism of the switch recombination process. We have deleted the entire switch tandem repeat element (Sμ) from the murine μ H chain gene. We find that the Sμ tandem repeats are not required for class switching in the mouse immunoglobulin H-chain locus, although the efficiency of switching is clearly reduced. Our data demonstrate that sequences outside of the Sμ tandem repeats must be capable of directing the class switch mechanism. The maintenance of the highly repeated Sμ element during evolution appears to reflect selection for a highly efficient switching process rather than selection for a required sequence element

Ecological history affects zooplankton community responses to acidification

The effects of ecological history are frequently ignored in attempts to predict community responses to environmental change. In this study, we explored the possibility that ecological history can cause differences in community responses to perturbation using parallel acidification experiments in three sites with different pH histories in the Northern Highland Lake District of Wisconsin, USA. In Trout Lake, high acid neutralizing capacity had historically buffered changes in pH. In contrast, the two basins of Little Rock Lake (Little Rock-Reference and Little Rock-Treatment) had experienced seasonal fluctuations in pH. Furthermore, the two lake basins were separated with a curtain and Little Rock-Treatment was experimentally acidified in the late 1980s. In each site, we conducted mesocosm experiments to compare zooplankton community dynamics in control (ambient pH) and acidified (pH 4.7) treatments. Zooplankton community responses were strongest in Trout Lake and weakest in Little Rock-Treatment suggesting that ecological history affected responses to acidification. In part, variation in community sensitivity to acidification was driven by differences in species composition. However, the results of a reciprocal transplant experiment indicated that changes in the acid tolerance of populations during past acidification events may make zooplankton communities less sensitive to subsequent pH stress. Our study highlights the role that ecological history may play in community-level responses to environmental change