2,938 research outputs found
Cultural Diversity in the United States and Its Impact on Human Development
Previous studies have yielded mixed results on the impact of cultural diversity on economic performance. We find a positive relationship in the United States between cultural diversity and a comprehensive measure of human development that incorporates health, education, and income. We also disaggregate cultural diversity into three components including ethnicity, language, and religion. We find a positive relationship between human development and both religious and language diversity, and a negative relationship with ethnic diversity. These relationships are robust, using several alternative mathematical measures of diversity. Our results are consistent with diversity generating benefits from exposure to a variety of experiences, ideas, and skills while introducing costs due to difficulty in communication, difference in preferences, and conflict between polarized groups. We conclude that strong institutions are essential to maximize the benefits of diversity while mitigating the associated costs
Diversity in the Heartland of America: The Impact on Human Development in Indiana
This article is the third in a series of studies measuring the impact of cultural diversity on human development. We disaggregate cultural diversity into three components: ethnicity, language, and religion. The first study examined the impact of diversity internationally. We found that countries are worse off with greater diversity, especially religious diversity; however, we found that more-prosperous countries with strong institutions benefited from increased diversity. We concluded that strong institutions are essential to maximize the benefits of diversity while mitigating the associated costs. The second study examined the impact of diversity within the United States, where institutional strength was assumed to be relatively great and similar between states. We found an overall negative impact from diversity. Ethnic diversity was negatively associated with human development, while religious and language diversity had a positive impact. We concluded that in the United States, there is more tolerance for religious and language differences compared to ethnic differences. In this third study, we examine the impact of diversity within the state of Indiana. As with our national results, we find a generally negative relationship between human development and diversity. Ethnic diversity has a negative impact, while religious and language diversity are generally positive influences. Strong political and legal institutions may not be sufficient to extract net benefits from diversity if social attitudes that guide behavior are not supportive. The results suggest that net benefits from diversity in Indiana may depend on improvement of social attitudes and in commitment to social services that support historically disadvantaged minority groups
The design and synthesis of polymeric assemblies for materials applications : chemosensing, liquid crystal alignment and block copolymers
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2012.Vita. Cataloged from PDF version of thesis.Includes bibliographical references.Conjugated polymers are an indispensable class of materials that have advanced the development of optoelectronic device architectures; in part, due to their outstanding electronic and mechanical properties. This thesis explores the utility of rationally designed energy transfer cascades involving conjugated polymers that can be used in applications such as chemosensing and liquid crystal alignment. We begin by describing the design and development of a new transduction mechanism for the detection of cyclic ketones - molecules that are found in plasticized explosives. We discuss the synthesis of a new reporter dye bearing a receptor for cyclic ketones that is capable of undergoing efficient energy transfer with conjugated polymers. We further describe the optimization of a thin-film sensor comprised of these two components as well as its performance and selectivity. In the next chapter we describe the design and synthesis of two new polymers that are capable of undergoing the di-[Pi]-methane rearrangement. We begin by describing the synthesis and photochemistry of the polymers as well as a model compound. The polymers contain triplet sensitizers built into the polymer backbone thereby creating an energy transfer cascade that facilitates the di-a-methane rearrangement. These materials are then evaluated as liquid crystal alignment layers for optoelectronic applications. In the final chapter, we describe the end-capping of cross-coupling polymerizations using the hydroarylation of norbornadiene. This reaction is shown to be an efficient approach to generating macroinitiators which can be further polymerized using ring opening metathesis polymerization. These end-capped materials can also be crosslinked into hybrid materials that show promise as thin-film sensors for volatile organic compounds.by Jason R. Cox.Ph.D
Long-Term High-Temperature Stability of Functionalized Graphene Oxide Nanoplatelets in Arab-D and API Brine
Partially reduced graphene oxide (prGO) was covalently functionalized with a zwitterionic polymer polyzwitterionic polymer to afford a composite material with excellent dispersibility and long-term stability in high salinity brines including standard API and Arab-D found in deep oil reservoirs. When heated at 90 Ā°C, the dispersions remained stable in excess of 140 days. These results suggest the utility of imidazolium-based polymers for brine stabilization as well as the use of diazonium containing polymers for a āgrafting-toā approach to nanocarbon functionalization.Saudi Aramco (MIT Energy Initiative)Massachusetts Institute of Technology. Institute for Soldier NanotechnologiesCamille & Henry Dreyfus Foundation. Postdoctoral Program in Environmental Chemistry (Fellowship
The Washington University MultiMedia eXplorer
The Washington University MultiMedia eXplorer (MMX) is a complete, host-independent multimedia system capable of transmitting and receiving JPEG-compressed video, CD-quality audio, and high-resolution radiographic images over the Washington University broadband ATM network. If the host is equipped with an ATM interface card, normal network traffic is supported via T and Y connections. The MMX consists of an ATMizer and three multimedia subsystems. The ATMizer implements the host interface, the interface to the ATM network, and the interface to the three multimdeia channels. This paper describes the architecture of the MMX, the software used with the system, and the applications which have been developed to demonstrate the capability of broadband ATM networks for multimedia applications
Production Quality Video Over Broadband Networks: A Description of the System and Two Interactive Applications
The Washington University MultiMedia eXplorer (MMX) is a complete, host-independent multimedia system capable of transmitting and receiving JPEG-compressed video, CD-quality audio, and high-resolution radiographic images over the Washington University broadband ATM network. If the host is equipped with an ATM interface card, normal network traffic can be supported via an ATM extension port on the MMX. The major components of the MMX are an ATMizer and three multimedia channels. The ATMizer implements the host interface, the interface to the ATM network, and hte interface to the three multimdeia channels. This paper describes the architecture of the MMX, the software used with the system, and two applications which have been developed to demonstrate the capability of broadband ATM networks for multimedia applications
Monochromatic aberrations of the human eye in a large population
From both a fundamental and a clinical point of view, it is necessary to know the distribution of the eye's aberrations in the normal population and to be able to describe them as efficiently as possible. We used a modified Hartmann-Shack wave-front sensor to measure the monochromatic wave aberration of both eyes for 109 normal human subjects across a 5.7-mm pupil. We analyzed the distribution of the eye's aberrations in the population and found that most Zernike modes are relatively uncorrelated with each other across the population. A principal components analysis was applied to our wave-aberration measurements with the resulting principal components providing only a slightly more compact description of the population data than Zernike modes. This indicates that Zernike modes are efficient basis functions for describing the eye's wave aberration. Even though there appears to be a random variation in the eye's aberrations from subject to subject, many aberrations in the left eye were found to be significantly correlated with their counterparts in the right eye
Optimizing Colloidal Stability and Transport of Polysaccharide-Coated Magnetic Nanoparticles for Reservoir Management: Effects of Ion Specificity
In this work we explore the mechanisms of ion-specific stabilization of a polysaccharide-based coating for colloidal nanomaterials used within the oil & gas industry. While nanotechnology has wide prevalence across multiple industries, its utility within this sector is largely undeveloped but has potential applications in areas including (but not limited to) exploration, drilling and production processes. For example, reservoir contrast agents in the form of superparamagnetic nanoparticles could be used to accurately determine the residual oil saturation distribution in a reservoir and thus advise enhanced oil recovery (EOR) efforts. However, deployment of such materials in oil reservoirs proves challenging in cases where high salinity subsurface environments induce nanoparticle aggregation, leading to loss of mobility. Here, we report the synthesis and characterization of dextran-coated superparamagnetic iron oxide nanoparticles (Dex-SPIONs), the colloidal stability of which was evaluated in various brine formulations at elevated temperatures. Initial dynamic light scattering (DLS) measurements reveal a lack of contingency between particle stability and total electrolyte concentration for samples comprised of synthetic seawater and low-salinity brine, the latter fluid of which possesses higher ionic strength yet preserves colloidal integrity to a much greater extent than its seawater counterpart. Further experiments point to a calcium (Ca2+) ion-specific stabilization effect wherein surface complexation of Ca2+ ions to the dextran periphery improves carbohydrate hydration and thus enhances colloidal stability. Ion selective electrode (ISE) measurements provide additional evidence of the Ca2+ - dextran binding interaction, the role of which also factors significantly into mitigation of polysaccharide degradation [as demonstrated through gel permeation chromatography (GPC)]. Finally, we assess the transport of Dex-SPIONs through porous media, including examination of retention properties with respect to variances in ionic composition
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A Gpr120-selective agonist improves insulin resistance and chronic inflammation in obese mice.
It is well known that the Ļ-3 fatty acids (Ļ-3-FAs; also known as n-3 fatty acids) can exert potent anti-inflammatory effects. Commonly consumed as fish products, dietary supplements and pharmaceuticals, Ļ-3-FAs have a number of health benefits ascribed to them, including reduced plasma triglyceride levels, amelioration of atherosclerosis and increased insulin sensitivity. We reported that Gpr120 is the functional receptor for these fatty acids and that Ļ-3-FAs produce robust anti-inflammatory, insulin-sensitizing effects, both in vivo and in vitro, in a Gpr120-dependent manner. Indeed, genetic variants that predispose to obesity and diabetes have been described in the gene encoding GPR120 in humans (FFAR4). However, the amount of fish oils that would have to be consumed to sustain chronic agonism of Gpr120 is too high to be practical, and, thus, a high-affinity small-molecule Gpr120 agonist would be of potential clinical benefit. Accordingly, Gpr120 is a widely studied drug discovery target within the pharmaceutical industry. Gpr40 is another lipid-sensing G protein-coupled receptor, and it has been difficult to identify compounds with a high degree of selectivity for Gpr120 over Gpr40 (ref. 11). Here we report that a selective high-affinity, orally available, small-molecule Gpr120 agonist (cpdA) exerts potent anti-inflammatory effects on macrophages in vitro and in obese mice in vivo. Gpr120 agonist treatment of high-fat diet-fed obese mice causes improved glucose tolerance, decreased hyperinsulinemia, increased insulin sensitivity and decreased hepatic steatosis. This suggests that Gpr120 agonists could become new insulin-sensitizing drugs for the treatment of type 2 diabetes and other human insulin-resistant states in the future
Delays in Leniency Application: Is There Really a Race to the Enforcer's Door?
This paper studies cartelsā strategic behavior in delaying leniency applications, a take-up decision that has been ignored in the previous literature. Using European Commission decisions issued over a 16-year span, we show, contrary to common beliefs and the existing literature, that conspirators
often apply for leniency long after a cartel collapses. We estimate hazard and probit models to study the determinants of leniency-application delays. Statistical tests find that delays are symmetrically affected by antitrust policies and macroeconomic fluctuations. Our results shed light on the design of
enforcement programs against cartels and other forms of conspiracy
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