Inter-laboratory variability of the Marshall test method for asphalt concrete

Statistical quality control measures, such as used by the West Virginia Division of Highways (WVDOH), require quantification of the variability of the test methods to set meaningful material acceptance parameters. The Division currently uses the Marshall method for asphalt concrete mix design and quality control. Although the Marshall method will be replaced as the Division transitions to the Superpave method, in the interim, the Division will continue to use the Marshall method. The objective of this project was to determine multi-laboratory precision statements for the Marshall method that the WVDOH can use in developing statistically based quality acceptance specifications.;An experiment was designed to generate the data needed for the development of precision statements for the Marshall method. An inter-laboratory study was performed in accordance with ASTM standards to evaluate the multi-laboratory variability of test methods. The experiment included three WVDOH asphalt concrete types. A side issue evaluated during this project was mixing of large quantities of material needed for the 152mm Marshall samples and for Superpave. A five gallon bucket style mixer was evaluated, and operating procedures were established. (Abstract shortened by UMI.)

Measuring the efficiency of capital allocation in commercial banking

Commercial banks leverage their equity capital with demandable debt that participates in the economy's payments system. The distinctive nature of this debt generates an unusual degree of liquidity risk that can, at times, threaten the payments system. To reduce this threat, insurance protects deposits; and to reduce the moral hazard problems of the debt contract and deposit insurance, bank regulation constrains risk-taking and defines standards of capital adequacy. The inherent liquidity risk of demandable debt as well as potential regulatory penalties for poor financial performance creates the potential for costly episodes of financial distress that affects banks' employment of capital. ; The existence of financial-distress costs implies that many banks are likely to take actions, such as holding additional capital, that increase bank safety at the expense of short-run returns. While such a strategy may reduce average returns in the short run, it may maximize the market value of the bank by protecting charter value and protecting against regulatory interventions. On the other hand, some banks whose charter values are low may have an incentive to follow a higher risk strategy, one that increases average return at the expense of greater risk of financial distress and regulatory intervention. ; This paper examines how banks' employment of capital in their production plans affects their "market value" efficiency. The authors develop a market-based measure of production efficiency and implement it on a sample of publicly traded bank holding companies. Our evidence indicates that banks' efficiency and, hence, the market value of their assets are influenced by the level and allocation of capital. However, even controlling for the effect of size, we find that the influence of equity capital differs markedly between banks with higher capital-to-assets ratios and those with lower ratios. For inefficient banks with higher capital-to-assets ratios, marginal increases in capitalization and asset quality boost their market-value efficiency. For inefficient banks with lower levels of capitalization, the signs of these effects are reversed. Controlling for asset size, it appears that less capitalized banks cannot afford to mimic the investment strategy of more capitalized banks, which may be using this greater capitalization to signal their safety to financial markets.Bank capital

Influencing park visitor behavior, a belief based approach.

Communication is a key component in management strategies designed to influence park visitor behavior and minimize social and ecological impacts. However, messages targeting management problems are often delivered without a real understanding of the specific underlying visitor beliefs. This paper applies the theory of planned behavior in the design and evaluation of messages targeting park visitor induced management problems. The method enables specific identification of how messages influence visitor beliefs and behavior. This enables managers to target and refine their messages in a measured, purposeful way for maximum effectiveness. Belief elicitation and measurement surveys were conducted at two Australian park sites, Badger Weir picnic area and Yellagonga Regional Park. The survey results informed the content of messages targeting specific problem behaviors at each site. Message interventions were installed at each site and their effectiveness evaluated based on a second belief measurement survey, and observations of visitor behavior. While the interventions were effective, repeat visitors with strong intentions and habitual behaviors seemed less prone to influence using this method. Despite overall increases in compliance at the two sites, the tested interventions were not successful in influencing salient beliefs or corresponding attitudes of these highly experienced visitors. This presents an additional challenge to parks managers. Visitors who engage in habitual behavior require an alternative approach involving different messages and different message delivery systems relative to their counter-parts. While more overt enforcement could be applied to address entrenched behaviors, alternative efforts might begin in the communities where local repeat visitors live, using a campaign style of communication

The structure and petrology of the Cnoc nan Cuilean Intrusion, Loch Loyal Syenite Complex, NW Scotland

In NW Scotland, several alkaline intrusive complexes of Silurian age intrude the Caledonian orogenic front. The most northerly is the Loch Loyal Syenite Complex, which is divided into three separate intrusions (Ben Loyal, Beinn Stumanadh and Cnoc nan Cuilean). Mapping of the Cnoc nan Cuilean intrusion shows two main zones: a Mixed Syenite Zone (MZ) and a Massive Leucosyenite Zone (LZ), with a gradational contact. The MZ forms a lopolith, with multiple syenitic lithologies, including early basic melasyenites and later felsic leucosyenites. Leucosyenite melts mixed and mingled with melasyenites, resulting in extreme heterogeneity within the MZ. Continued felsic magmatism resulted in formation of the relatively homogeneous LZ, invading western parts of the MZ and now forming the topographically highest terrane. The identification of pegmatites, microgranitic veins and unusual biotite-magnetite veins demonstrates the intrusion's complex petrogenesis. Cross-sections have been used to create a novel 3D GoCad™ model contributing to our understanding of the intrusion. The Loch Loyal Syenite Complex is known to have relatively high concentrations of rare earth elements (REEs), and thus the area has potential economic and strategic value. At Cnoc nan Cuilean, abundant REE-bearing allanite is present within melasyenites of the MZ. Extensive hydrothermal alteration of melasyenites here formed steeply dipping biotite-magnetite veins, most enriched in allanite and other REE-bearing accessories. This study has thus identified the area of greatest importance for further study of REE enrichment processes in the Cnoc nan Cuilean intrusion

Structure-based discovery of fiber-binding compounds that reduce the cytotoxicity of amyloid beta.

Amyloid protein aggregates are associated with dozens of devastating diseases including Alzheimer's, Parkinson's, ALS, and diabetes type 2. While structure-based discovery of compounds has been effective in combating numerous infectious and metabolic diseases, ignorance of amyloid structure has hindered similar approaches to amyloid disease. Here we show that knowledge of the atomic structure of one of the adhesive, steric-zipper segments of the amyloid-beta (Aβ) protein of Alzheimer's disease, when coupled with computational methods, identifies eight diverse but mainly flat compounds and three compound derivatives that reduce Aβ cytotoxicity against mammalian cells by up to 90%. Although these compounds bind to Aβ fibers, they do not reduce fiber formation of Aβ. Structure-activity relationship studies of the fiber-binding compounds and their derivatives suggest that compound binding increases fiber stability and decreases fiber toxicity, perhaps by shifting the equilibrium of Aβ from oligomers to fibers. DOI:http://dx.doi.org/10.7554/eLife.00857.001

Detecting Heart Disease from Multi-View Ultrasound Images via Supervised Attention Multiple Instance Learning

Aortic stenosis (AS) is a degenerative valve condition that causes substantial morbidity and mortality. This condition is under-diagnosed and under-treated. In clinical practice, AS is diagnosed with expert review of transthoracic echocardiography, which produces dozens of ultrasound images of the heart. Only some of these views show the aortic valve. To automate screening for AS, deep networks must learn to mimic a human expert's ability to identify views of the aortic valve then aggregate across these relevant images to produce a study-level diagnosis. We find previous approaches to AS detection yield insufficient accuracy due to relying on inflexible averages across images. We further find that off-the-shelf attention-based multiple instance learning (MIL) performs poorly. We contribute a new end-to-end MIL approach with two key methodological innovations. First, a supervised attention technique guides the learned attention mechanism to favor relevant views. Second, a novel self-supervised pretraining strategy applies contrastive learning on the representation of the whole study instead of individual images as commonly done in prior literature. Experiments on an open-access dataset and an external validation set show that our approach yields higher accuracy while reducing model size.Comment: multiple-instance learning; self-supervised learning; semi-supervised learning; medical imagin

Do Bankers Sacrifice Value to Build Empires? Managerial Incentives, Industry Consolidation and Financial Performance

Bank consolidation is a global phenomenon that may enhance stakeholders' value if managers do not sacrifice value to build empires. We find strong evidence of managerial entrenchment at U.S. bank holding companies that have higher levels of managerial ownership, better growth opportunities, poorer financial performance, and smaller asset size. At banks without entrenched management, both asset acquisitions and sales are associated with improved performance. At banks with entrenched management, sales are related to smaller improvements while acquisitions are associated with worse performance. Consistent with scale economies, an increase in assets by internal growth is associated with better performance at most banks. Key Words: consolidation, acquisitions, managerial incentives, efficiency, agency problems, corporate control, stochastic frontier

Mutation of the co-chaperone Tsc1 in bladder cancer diminishes Hsp90 acetylation and reduces drug sensitivity and selectivity

The molecular chaperone Heat shock protein 90 (Hsp90) is essential for the folding, stability, and activity of several drivers of oncogenesis. Hsp90 inhibitors are currently under clinical evaluation for cancer treatment, however their efficacy is limited by lack of biomarkers to optimize patient selection. We have recently identified the tumor suppressor tuberous sclerosis complex 1 (Tsc1) as a new co-chaperone of Hsp90 that affects Hsp90 binding to its inhibitors. Highly variable mutations of TSC1 have been previously identified in bladder cancer and correlate with sensitivity to the Hsp90 inhibitors. Here we showed loss of TSC1 leads to hypoacetylation of Hsp90-K407/K419 and subsequent decreased binding to the Hsp90 inhibitor ganetespib. Pharmacologic inhibition of histone deacetylases (HDACs) restores acetylation of Hsp90 and sensitizes Tsc1-mutant bladder cancer cells to ganetespib, resulting in apoptosis. Our findings suggest that TSC1 status may predict response to Hsp90 inhibitors in patients with bladder cancer, and co-targeting HDACs can sensitize tumors with Tsc1 mutations to Hsp90 inhibitors

Modal quantum theory

We present a discrete model theory similar in structure to ordinary quantum mechanics, but based on a finite field instead of complex amplitudes. The interpretation of this theory involves only the "modal" concepts of possibility and necessity rather than quantitative probability measures. Despite its simplicity, our model theory includes entangled states and has versions of both Bell's theorem and the no cloning theorem.Comment: Presented at the 7th Workshop on Quantum Physics and Logic, Oxford University (29-30 May 2010). Revised 1 Aug 2011 in response to referee comment

Asymmetry During Maximal Sprint Performance in 11- to 16-Year-Old Boys

Purpose: The aim of this study was to examine the influence of age and maturation upon magnitude of asymmetry in the force, stiffness and the spatiotemporal determinants of maximal sprint speed in a large cohort of boys. Methods: 344 boys between the ages of 11 and 16 years completed an anthropometric assessment and a 35 m sprint test, during which sprint performance was recorded via a ground-level optical measurement system. Maximal sprint velocity, as well as asymmetry in spatiotemporal variables, modeled force and stiffness data were established for each participant. For analysis, participants were grouped into chronological age, maturation and percentile groups. Results: The range of mean asymmetry across age groups and variables was 2.3–12.6%. The magnitude of asymmetry in all the sprint variables was not significantly different across age and maturation groups (p > .05), except relative leg stiffness (p < .05). No strong relationships between asymmetry in sprint variables and maximal sprint velocity were evident (rs < .39). Conclusion: These results provide a novel benchmark for the expected magnitude of asymmetry in a large cohort of uninjured boys during maximal sprint performance. Asymmetry in sprint performance is largely unaffected by age or maturation and no strong relationships exist between the magnitude of asymmetry and maximal sprint velocity