Innovation incentives and competition in the hard disk drive industry

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Economics, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 52-53).Firms in the hard disk drive industry are continually engaging in R & D and improving the quality of their products. We explore various determinants of the product innovation incentives for firms concerned with both their static and expected future profitability. We estimate the observed innovation outcomes as a function of market condition variables which have significant impact on innovation decisions. In addition, we estimate logit utilities that describe the marginal willingness to pay for quality improvements. One aspect of utility is that the willingness to pay for faster access time to data may be initially low but increases over time. The firms' decisions to introduce faster access time are partly motivated by dynamic considerations.by Xiaohua Sherry Wu.S.M

Influence of Social Context and Affect on Individuals\u27 Implementation of Information Security Safeguards

Individuals’ use of safeguards against information security risks is commonly conceptualized as the result of a risk-benefit analysis. This economic perspective assumes a “rational actor” whereas risk is subjectively perceived by people who may be influenced by a number of social, psychological, cultural, and other “soft” factors. Their decisions thus may deviate from what economic risk assessment analysis would dictate. In this respect, a phenomenon interesting to study is that on social network sites (SNSes) people tend to, despite a number of potential security risks, provide an amount of personal information that they would otherwise frown upon. In this study we explore how people’s affect toward online social networking may impact their use of privacy safeguards. Since building social capital is a main purpose of online social networking, we use social capital theory to examine some potential contextual influence on the formation of the affect. More specifically, we adopt the perspective proposed by Nahapiet and Ghoshal (1998), which views social capital as a composite of structural, relational, and cognitive capitals. Preliminary analysis of 271 survey responses shows that (a) a person’s structural and relational embeddedness in her online social networks, as well as her cognitive ability in maintaining those networks, are positively related to her affect toward SNSes; (b) a person’s affect toward SNSes moderates the relationship between her perception of privacy risk and the privacy safeguards she implements on the SNSes

Comprehensive Bioinformatic Analysis of Glycoside Hydrolase Family 10 Proteins

Glycoside Hydrolase Family 10 (GH10) contains endo-1, 4-β-xylanase which catalyzes the hydrolysis of xylan, the most abundant hemicellulose in lignocellulosic biomass. In this study, different bioinformatic approaches were used to comprehensively analyze the distribution, the phylogeny, the function and the evolutionary origin of a large GH10 protein dataset. The goal was to explore the correlation between sequence similarity and function of GH10 proteins to better understand xylan utilization pattern within the family. Predicted glycoside hydrolase family 10 sequences from fungal, bacterial, archaeal, and non-fungal eukaryotic genomes as well as biochemically characterized proteins were used to perform a phylogenetic analysis. Based on the tree topology, 626 GH10 sequences were classified into 50 well-supported subfamilies. Among the analyzed sequences, 42 remained unclustered. The complex topology of the family tree suggests multiple duplication events followed by lineage specific gene loss during evolution. In addition, the Maximum Likelihood phylogeny of GH10 proteins does not mirror the previously established species taxonomic tree, suggesting that the divergence of the GH10 family ancestral gene preceded the appearance of the eukaryotic lineages. A set of non-fungal GH10 proteins were manually curated employing criteria used in mycoCLAP, a database for biochemically characterized fungal lignocellulose active enzymes. Experimental data of biochemically characterized GH10 proteins were mapped onto the phylogenetic tree to establish relationships, if any, between biochemical properties and sequence similarity. Only 24 subfamilies contain members with characterization, demonstrating that 26 phylogenetically diverse subfamilies remain uncharacterized. Among the subfamilies with experimental data, a distantly related subfamily with tomatinase activity was identified. By comparing the tertiary structures of well-characterized subfamilies, I have identified subfamilies that display different xylan substrate preferences and hydrolysis patterns. Correlations were also observed between sequence similarity and the pH and/or temperature optimum in the GH10 family. The accumulation of mutations within subfamilies reflects how they have diverged over time. Subfamily discriminating residue analyses were performed to identify subfamily-specific polymorphisms. Detailed lists of subfamily discriminating residues are provided. The majority of these residues are involved in secondary structure formation based on alignment to 3D structures, suggesting they might be functionally and structurally important

Methodology for capturing and measuring dissolved mercury in natural waters using ion exchangers and instrumental neutron activation analysis

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1996.Includes bibliographical references (leaves 119-123).by Sherry C. Wu.M.S

Effective Delivery of PEGylated siRNA-Containing Lipoplexes to Extraperitoneal Tumours following Intraperitoneal Administration

Intraperitoneal (i.p.) administration of small interfering RNA (siRNA) has, to date, shown promise in treating tumours located within the peritoneal cavity. The ability of these siRNA molecules to reach extraperitoneal tumours following i.p. administration is, however, yet to be investigated. Here, we examined the impact of PEGylation on the biodistribution of i.p. administered nucleic acids-containing lipoplexes. We showed that in contrast to non-PEGylated liposomes, PEGylated liposomes can deliver siRNA efficiently to extraperitoneal tumours following i.p. administration, resulting in a 45% reduction in tumour size when the oncogene-targeted siRNA was used. This difference was likely contributed by the decreased uptake of PEGylated lipoplexes in the first-pass organs, and, in particular, we observed a 10-fold decrease in the macrophage uptake of these particles compared to non-PEGylated counterparts. Overall, our results indicated the potential of using PEGylated liposomes to deliver siRNA for the treatment of i.p. localized cancer with coexisting extraperitoneal metastasis

Federal Services for Constituents Available in Foreign Languages: Selected Sources

This report is a directory of sources on various federal constituent services available in foreign languages, to assist congressional offices in serving non-English speaking constituents. The topics covered are: access to jobs and workers’ issues, Americans with Disabilities Act, childcare, consumer protection, disaster relief, elder care, emergency preparedness, environmental protection, Federal Bureau of Investigation, food safety, health, higher education, homeland security, housing, immigration, immunizations, Medicaid, Medicare, the Presidency, retirement, Small Business Administration, Social Security Administration, taxes, telephone service, travel and tourism, veterans affairs, and voting

Federal Services for Constituents Available in Spanish: Selected Sources

This report is a directory of sources on various federal constituent services available in Spanish to assist congressional offices in serving Spanish-speaking constituents. The topics covered are: access to jobs and workers’ issues, Americans with Disabilities Act, childcare, consumer protection, disaster relief, elder care, emergency management, emergency preparedness, environmental protection, Federal Bureau of Investigation, food safety, health, higher education, homeland security, housing, immigration, immunizations, Medicaid, Medicare, the Presidency, retirement, Small Business Administration, Social Security Administration, taxes, telephone service, travel and tourism, veterans affairs, and voting