Is distance dying at last? Falling home bias in fixed effects models of patent citations

We examine the “home bias” of international knowledge spillovers as measured by the speed of patent citations (i.e. knowledge spreads slowly over international boundaries). We present the first compelling econometric evidence that the geographical localization of knowledge spillovers has fallen over time, as we would expect from the dramatic fall in communication and travel costs. Our proposed estimator controls for correlated fixed effects and censoring in duration models and we apply it to data on over two million citations between 1975 and 1999. Home bias declines substantially when we control for fixed effects: there is practically no home bias for the more “modern” sectors such as pharmaceuticals and information/communication technologies

Jewish Service Learning: An Analysis of Participant Jewish Identity and Program Characterisitcs

LBJ School of Public Affair

Is Distance Dying at Last? Falling Home Bias in Fixed Effects Models of Patent Citations

We examine the home bias of international knowledge spillovers as measured by the speed of patent citations (i.e. knowledge spreads slowly over international boundaries). We present the first compelling econometric evidence that the geographical localization of knowledge spillovers has fallen over time, as we would expect from the dramatic fall in communication and travel costs. Our proposed estimator controls for correlated fixed effects and censoring in duration models and we apply it to data on over two million citations between 1975 and 1999. Home bias declines substantially when we control for fixed effects: there is practically no home bias for the more modern sectors such as pharmaceuticals and information/communication technologies.

Is Distance Dying at Last? Falling Home Bias in Fixed Effects Models of Patent Citations

We examine the "home bias" of international knowledge spillovers as measured by the speed of patent citations (i.e. knowledge spreads slowly over international boundaries). We present the first compelling econometric evidence that the geographical localization of knowledge spillovers has fallen over time, as we would expect from the dramatic fall in communication and travel costs. Our proposed estimator controls for correlated fixed effects and censoring in duration models and we apply it to data on over two million citations between 1975 and 1999. Home bias declines substantially when we control for fixed effects: there is practically no home bias for the more "modern" sectors such as pharmaceuticals and information/communication technologies.Fixed effects, home bias, patent citations, knowledge spillovers

Accounting historians engaging with scholars inside and outside accounting: issues, opportunities and obstacles

Originating in a panel presentation at the eighth Accounting History International Conference, this study offers a reflection on the issues, opportunities and obstacles which may arise when accounting historians engage with other accounting scholars and scholars outside of accounting. Supporting the view that accounting scholars need and should make an effort to engage with other scholars inside and outside accounting, various aspects are considered as enhancing the interdisciplinarity of accounting history research. Then, issues such as researchers and the community, research problems, theories, methods and data are addressed. The opportunities arising from interdisciplinary interactions with a wide range of scholars are then developed. Finally, the potential obstacles are addressed. These obstacles can be overcome by the development of robust communication and the invention of a new genre of discourse and research focus and by working with those outside our discipline and embracing the challenge of the new and the different

Is distance dying at last? Falling home bias in fixed effects models of patent citations

We examine the "home bias" of knowledge spillovers (the idea that knowledge spreads more slowly over international boundaries than within them) as measured by the speed of patent citations. We present econometric evidence that the geographical localization of knowledge spillovers has fallen over time, as we would expect from the dramatic fall in communication and travel costs. Our proposed estimator controls for correlated fixed effects and censoring in duration models and we apply it to data on over two million patent citations between 1975 and 1999. Home bias is exaggerated in models that do not control for fixed effects. The fall in home bias over time is weaker for the pharmaceuticals and information/communication technology sectors where agglomeration externalities may remain strong.

Estimating spillovers using imprecisely measured networks

In many experimental contexts, whether and how network interactions impact the outcome of interest for both treated and untreated individuals are key concerns. Networks data is often assumed to perfectly represent these possible interactions. This paper considers the problem of estimating treatment effects when measured connections are, instead, a noisy representation of the true spillover pathways. We show that existing methods, using the potential outcomes framework, yield biased estimators in the presence of this mismeasurement. We develop a new method, using a class of mixture models, that can account for missing connections and discuss its estimation via the Expectation-Maximization algorithm. We check our method's performance by simulating experiments on real network data from 43 villages in India. Finally, we use data from a previously published study to show that estimates using our method are more robust to the choice of network measure

THE ENTEROHEMORRHAGIC ESCHERICHIA COLI EFFECTOR PROTEIN NLEF BINDS MAMMALIAN HOST PROTEINS

The extracellular human pathogens enterohemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC) and the related mouse pathogen Citrobacter rodentium inject type III secretion system (T3SS) effector proteins to promote their replication, survival and transmission. The mechanisms of action and the host targets of T3SS effectors are under active investigation because of their importance to bacterial virulence. The non-locus of enterocyte effacement (LEE)-encoded protein F, NleF, contributes to E. coli and Citrobacter colonization of animals through an unclear mechanism. Here we sought to characterize the host binding partners of NleF. Using a yeast two-hybrid screen, we identified a set of mammalian proteins as NleF-binding partners including Tmp21, a type-I integral membrane protein and COPI-vesicle receptor involved in trans-Golgi network function. We confirmed this interaction using bacterial two-hybrid, immunoprecipitation and bimolecular fluorescence complementation (BiFC). To consider the effects of NleF on protein trafficking, we expressed a temperature-sensitive vesicular stomatitis virus glycoprotein (VSVG) with temperature dependent localization and monitored protein trafficking. We determined that NleF does not block, but rather slows the intracellular trafficking of VSVG from endoplasmic reticulum to Golgi

Protein engineering strategy for the stabilization of HIV-1 α-helical peptides

2019 Spring.Includes bibliographical references.Many disease-relevant protein-protein interactions (PPIs) contain an alpha helix and helical binding cleft at their interface. Disruption of these interactions with helical peptide mimics is a validated therapeutic strategy. However, short peptides typically do not fold into stable helices, which significantly lowers their in vivo stability. Researches have reported methods for helical peptide stabilization but, these approaches rely on laborious, and often expensive, chemical synthesis and purification. The research I have preformed aims to stabilize disease-relevant helices through protein engineering. In contrast to chemically constrained helical peptides, a protein can be expressed in a cellular system on a much larger scale. Recently, we reported a new strategy termed "helix-grafted display" that overcomes the traditional hurdles of helical mimics and applied it to the challenge of suppressing HIV entry. Our helix grafted proteins, potently inhibits formation of the extracellular PPI involving C-peptide helix, and HIV gp41 N-peptide trimer, as tested in HIV CD4+ cells. Further optimization of the helical sequence by yeast display yielded new proteins that suppress HIV-1 entry and express substantially better in E. coli. Furthermore, fusion proteins designed to improve the serum stability of these helix grafted proteins have been made that potently suppress HIV-1 entry. Collectively, I report a potential cocktail of evolved HIV-1 entry inhibitors that are functional against an Enfuvirtide-resistant strain and are designed for serum stabilities that rival current monoclonal antibody drugs