Mostrando recursos 1 - 20 de 109

  1. The process of discovery

    Fishman, Jay Alan

  2. The process of discovery

    Fishman, Jay Alan

  3. Identification of Exogenous Forms of Human-Tropic Porcine Endogenous Retrovirus in Miniature Swine

    Fishman, Jay Alan; Wood, James C.; Quinn, Gary; Suling, Kristen M.; Oldmixon, Beth A.; Van Tine, Brian A.; Cina, Robert; Arn, Scott; Huang, Christine A.; Scobie, Linda; Onions, David E.; Sachs, David H.; Schuurman, Henk-Jan; Patience, Clive
    The replication of porcine endogenous retrovirus subgroup A (PERV-A) and PERV-B in certain human cell lines indicates that PERV may pose an infectious risk in clinical xenotransplantation. We have previously reported that human-tropic PERVs isolated from infected human cells following cocultivation with miniature swine peripheral blood mononuclear cells (PBMC) are recombinants of PERV-A with PERV-C. Here, we report that these recombinants are exogenous viruses in miniature swine; i.e., they are not present in the germ line DNA. These viruses were invariably present in miniature swine that transmitted PERV to human cells and were also identified in some miniature swine that...

  4. Identification of Exogenous Forms of Human-Tropic Porcine Endogenous Retrovirus in Miniature Swine

    Fishman, Jay Alan; Wood, James C.; Quinn, Gary; Suling, Kristen M.; Oldmixon, Beth A.; Van Tine, Brian A.; Cina, Robert; Arn, Scott; Huang, Christine A.; Scobie, Linda; Onions, David E.; Sachs, David H.; Schuurman, Henk-Jan; Patience, Clive
    The replication of porcine endogenous retrovirus subgroup A (PERV-A) and PERV-B in certain human cell lines indicates that PERV may pose an infectious risk in clinical xenotransplantation. We have previously reported that human-tropic PERVs isolated from infected human cells following cocultivation with miniature swine peripheral blood mononuclear cells (PBMC) are recombinants of PERV-A with PERV-C. Here, we report that these recombinants are exogenous viruses in miniature swine; i.e., they are not present in the germ line DNA. These viruses were invariably present in miniature swine that transmitted PERV to human cells and were also identified in some miniature swine that...

  5. Prevention of Infection Due to Pneumocystis spp. in Human Immunodeficiency Virus-Negative Immunocompromised Patients

    Fishman, Jay Alan; Rodriquez, Martin
    Pneumocystis was initially identified in the lungs of rats as a stage in the life cycle of Trypanosoma cruzi (in 1909 by Chagas and in 1910 by Carini). The first case of Pneumocystis infection in humans was described by van der Meer and Brug in 1942 (167); Jirovec has been credited with describing epidemic in- fection in humans in the 1950s (85). Pneumocystis carinii was thought to be a protozoan parasite based on morphologic appearance, proposed life cycle, and antimicrobial susceptibil- ities. Subsequent phylogenic analyses using rRNA sequences suggested that the organism was more closely related to the fungi despite...

  6. Prevention of Infection Due to Pneumocystis spp. in Human Immunodeficiency Virus-Negative Immunocompromised Patients

    Fishman, Jay Alan; Rodriquez, Martin
    Pneumocystis was initially identified in the lungs of rats as a stage in the life cycle of Trypanosoma cruzi (in 1909 by Chagas and in 1910 by Carini). The first case of Pneumocystis infection in humans was described by van der Meer and Brug in 1942 (167); Jirovec has been credited with describing epidemic in- fection in humans in the 1950s (85). Pneumocystis carinii was thought to be a protozoan parasite based on morphologic appearance, proposed life cycle, and antimicrobial susceptibil- ities. Subsequent phylogenic analyses using rRNA sequences suggested that the organism was more closely related to the fungi despite...

  7. The intrinsic value of choice: The propensity to under-delegate in the face of potential gains and losses

    Bobadilla-Suarez, Sebastian; Sunstein, Cass R.; Sharot, Tali
    Human beings are often faced with a pervasive problem: whether to make their own decision or to delegate the decision task to someone else. Here, we test whether people are inclined to forgo monetary rewards in order to retain agency when faced with choices that could lead to losses and gains. In a simple choice task, we show that participants choose to pay in order to control their own payoff more than they should if they were to maximize monetary rewards and minimize monetary losses. This tendency cannot be explained by participants’ overconfidence in their own ability, as their perceived...

  8. Should Governments Invest More in Nudging?

    Benartzi, Shlomo; Beshears, John; Milkman, Katherine L.; Sunstein, Cass R.; Thaler, Richard H.; Shankar, Maya; Tucker-Ray, Will; Congdon, William J.; Galing, Steven
    Governments are increasingly adopting behavioral science techniques for changing individual behavior in pursuit of policy objectives. The types of “nudge” interventions that governments are now adopting alter people’s decisions without coercion or significant changes to economic incentives. We calculated ratios of impact to cost for nudge interventions and for traditional policy tools, such as tax incentives and other financial inducements, and we found that nudge interventions often compare favorably with traditional interventions. We conclude that nudging is a valuable approach that should be used more often in conjunction with traditional policies, but more calculations are needed to determine the relative...

  9. Can States Take Over and Turn Around School Districts? Evidence from Lawrence, Massachusetts

    Schueler, Beth; Goodman, Joshua Samuel; Deming, David James
    The Federal government has spent billions of dollars to support turnarounds of low-achieving schools, yet most evidence on the impact of such turnarounds comes from high-profile, exceptional settings and not from examples driven by state policy decisions at scale. In this paper, we study the impact of state takeover and district-level turnaround in Lawrence, Massachusetts. Takeover of the Lawrence Public School (LPS) district was driven by the state’s accountability system, which increases state control in response to chronic underperformance. We find that the first two years of the LPS turnaround produced large achievement gains in math and modest gains in...

  10. Redistribution in a model of voting and campaign contributions

    Campante, Filipe Robin
    I propose a framework in which individual political participation can take two distinct forms, voting and contributing resources to campaigns, in a context in which the negligible impact of any individual’s actions on aggregate outcomes is fully recognized by all agents. I then use the framework to reassess the relationship between inequality and redistribution. The model shows that, even though each contribution has a negligible impact, the interaction between contributions and voting leads to an endogenous wealth bias in the political process, as the advantage of wealthier individuals in providing contributions encourages parties to move their platforms closer to those...

  11. Redistribution in a model of voting and campaign contributions

    Campante, Filipe Robin
    I propose a framework in which individual political participation can take two distinct forms, voting and contributing resources to campaigns, in a context in which the negligible impact of any individual’s actions on aggregate outcomes is fully recognized by all agents. I then use the framework to reassess the relationship between inequality and redistribution. The model shows that, even though each contribution has a negligible impact, the interaction between contributions and voting leads to an endogenous wealth bias in the political process, as the advantage of wealthier individuals in providing contributions encourages parties to move their platforms closer to those...

  12. Intensive Math Instruction and Educational Attainment

    Cortes, Kalena E.; Goodman, Joshua Samuel; Nomi, Takako
    We study an intensive math instruction policy that assigned low-skilled 9th graders to an algebra course that doubled instructional time, altered peer composition and emphasized problem solving skills. A regression discontinuity design shows substantial positive impacts of double-dose algebra on credits earned, test scores, high school graduation and college enrollment rates. Test score effects under-predict attainment effects, highlighting the importance of long-run evaluation of such a policy. Perhaps because the intervention focused on verbal exposition of mathematical concepts, the impact was largest for students with below average reading skills, emphasizing the need to target interventions toward appropriately skilled students.

  13. Access to 4-Year Public Colleges and Degree Completion

    Goodman, Joshua Samuel; Hurwitz, Michael; Smith, Jonathan
    Does access to 4-year colleges affect degree completion for students who would otherwise attend 2-year colleges? Admission to Georgia’s 4-year public sector requires minimum SAT scores. Regression discontinuity estimates show that access to this sector increases 4-year college enrollment and college quality, largely by diverting students from 2-year colleges. Access substantially increases bachelor’s degree completion rates for these relatively low-skilled students. SAT retaking behavior suggests students value access to 4-year public colleges, though perhaps less than they should. Our results imply that absolute college quality matters more than match quality, and they suggest potential unintended consequences of free community college...

  14. Failure to CAPTCHA Attention: Null Results from an Honesty Priming Experiment in Guatemala

    Kettle, Stewart; Hernandez, Marco; Sanders, Michael; Hauser, Oliver; Ruda, Simon
    We report results from a large online randomised tax experiment in Guatemala. The trial involves short messages and choices presented to taxpayers as part of a CAPTCHA pop-up window immediately before they file a tax return, with the aim of priming honest declarations. In total our sample includes 627,242 taxpayers and 3,232,430 tax declarations made over four months. Treatments include: honesty declaration; information about public goods; information about penalties for dishonesty, questions allowing a taxpayer to choose which public good they think tax money should be spent on; or questions allowing a taxpayer to state a view on the penalty...

  15. Should the WHO withdraw support for mass deworming?

    Croke, Kevin; Hicks, Joan Hamory; Hsu, Eric; Kremer, Michael; Miguel, Edward

  16. More Evidence on the Effects of Deworming: What Lessons Can We Learn?

    Croke, Kevin; Hsu, Eric; Kremer, Michael

  17. Merit Aid, College Quality and College Completion: Massachusetts' Adams Scholarship as an In-Kind Subsidy.

    Cohodes, Sarah; Goodman, Joshua Samuel
    We analyze a Massachusetts merit aid program that gives high-scoring students tuition waivers at in-state public colleges with lower graduation rates than available alternative colleges. A regression discontinuity design comparing students just above and below the eligibility threshold finds that students are remarkably willing to forgo college quality and that scholarship use actually lowered college completion rates. These results suggest that college quality affects college completion rates. The theoretical prediction that in-kind subsidies of public institutions can reduce consumption of the subsidized good is shown to be empirically important.

  18. Information as Influence: How Institutions Mediate the Impact of Scientific Assessments on Global Environmental Affairs

    Clark, William C.; Mitchell, Ronald; Cash, David; Alcock, Frank
    The recognition that information matters in world affairs raises a number of questions as to when, how, and under what conditions it influences the behavior of policy actors. Despite the vast and growing array of institutions involved in collecting, analyzing, and disseminating information potentially relevant to global governance generally, and global environmental change specifically, our understanding of the role that these "information institutions" play in world affairs remains limited. This paper examines how institutions mediate the impact of scientific assessments on global environmental affairs and highlights the pathways through which information has influence on the policy and politics of environmental...

  19. Using inclusive wealth for policy evaluation: Application to electricity infrastructure planning in oil-exporting countries

    Collins, Ross D.; Selin, Noelle E.; de Weck, Olivier L.; Clark, William C.
    Decision-makers often seek to design policies that support sustainable development. Prospective evaluations of how effectively such policies are likely to meet sustainability goals have nonetheless remained relatively challenging. Evaluating policies against sustainability goals can be facilitated through the inclusive wealth framework, which characterizes development in terms of the value to society of its underlying capital assets, and defines development to be potentially sustainable if that value does not decline over time. The inclusive wealth approach has been developed at a theoretical level and previously applied to retrospective evaluations. Here, we apply inclusive wealth theory to prospective policy evaluation coupled with...

  20. Getting an Honest Answer: Clickers in the Classroom

    Levy, Dan; Yardley, Joshua Shawn; Zeckhauser, Richard Jay
    Some preliminary experiments the authors conducted suggested that when instructors asked students to raise their hands to indicate support for a certain answer or position, the results they got were very different than those that would be obtained through the use of polling devices (i.e. clickers). The authors hypothesized that raising hands is an act subject to peer influence, and hence serves as a poor indicator of what students are really thinking. The authors therefore conducted experiments more broadly and systematically across several classrooms, and assessed the types of questions in which the raising of hands were more (or less)...

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