Glimmers: Resolving the Privacy/Trust Quagmire

Many successful services rely on trustworthy contributions from users. To establish that trust, such services often require access to privacy-sensitive information from users, thus creating a conflict between privacy and trust. Although it is likely impractical to expect both absolute privacy and trustworthiness at the same time, we argue that the current state of things, where individual privacy is usually sacrificed at the altar of trustworthy services, can be improved with a pragmatic $Glimmer$ $of$ $Trust$, which allows services to validate user contributions in a trustworthy way without forfeiting user privacy. We describe how trustworthy hardware such as Intel's SGX can be used client-side -- in contrast to much recent work exploring SGX in cloud services -- to realize the Glimmer architecture, and demonstrate how this realization is able to resolve the tension between privacy and trust in a variety of cases

Children balance theories and evidence in exploration, explanation, and learning

We look at the effect of evidence and prior beliefs on exploration, explanation and learning. In Experiment 1, we tested children both with and without differential prior beliefs about balance relationships (Center Theorists, mean: 82 months; Mass Theorists, mean: 89 months; No Theory children, mean: 62 months). Center and Mass Theory children who observed identical evidence explored the block differently depending on their beliefs. When the block was balanced at its geometric center (belief-violating to a Mass Theorist, but belief-consistent to a Center Theorist), Mass Theory children explored the block more, and Center Theory children showed the standard novelty preference; when the block was balanced at the center of mass, the pattern of results reversed. The No Theory children showed a novelty preference regardless of evidence. In Experiments 2 and 3, we follow-up on these findings, showing that both Mass and Center Theorists selectively and differentially appeal to auxiliary variables (e.g., a magnet) to explain evidence only when their beliefs are violated. We also show that children use the data to revise their predictions in the absence of the explanatory auxiliary variable but not in its presence. Taken together, these results suggest that children’s learning is at once conservative and flexible; children integrate evidence, prior beliefs, and competing causal hypotheses in their exploration, explanation, and learning.American Psychological Foundation (Elizabeth Munsterberg Koppitz Fellowship)James S. McDonnell Foundation (Collaborative Interdisciplinary Grant on Causal Reasoning)National Science Foundation (U.S.) (NSF Faculty Early Career Development Award)Templeton Foundation (Award

Degradation of lignin β-aryl ether units in Arabidopsis thaliana expressing LigD, LigF and LigG from Sphingomonas paucimobilis SYK-6

Lignin is a major polymer in the secondary plant cell wall and composed of hydrophobic interlinked hydroxyphenylpropanoid units. The presence of lignin hampers conversion of plant biomass into biofuels; plants with modified lignin are therefore being investigated for increased digestibility. The bacterium Sphingomonas paucimobilis produces lignin-degrading enzymes including LigD, LigF and LigG involved in cleaving the most abundant lignin interunit linkage, the beta-aryl ether bond. In this study, we expressed the LigD, LigF and LigG (LigDFG) genes in Arabidopsis thaliana to introduce postlignification modifications into the lignin structure. The three enzymes were targeted to the secretory pathway. Phenolic metabolite profiling and 2D HSQC NMR of the transgenic lines showed an increase in oxidized guaiacyl and syringyl units without concomitant increase in oxidized beta-aryl ether units, showing lignin bond cleavage. Saccharification yield increased significantly in transgenic lines expressing LigDFG, showing the applicability of our approach. Additional new information on substrate specificity of the LigDFG enzymes is also provided

Regimen durability in HIV-positive children andd adolescents initiating first-line art in a large public sector HIV cohort in South Africa

INTRODUCTION: In April 2010 tenofovir and abacavir replaced stavudine in public-sector first-line antiretroviral therapy (ART) for children under 20 years old in South Africa. The association of both abacavir and tenofovir with fewer side-effects and toxicities compared to stavudine could translate to increased durability of tenofovir or abacavir-based regimens. We evaluated changes over time in regimen durability for pediatric patients 3 to 19 years of age at 8 public sector clinics in Johannesburg, South Africa. METHODS: Cohort analysis of treatment naïve, non-pregnant pediatric patients from 3 to 19 years old initiated on ART between April 2004-December 2013. First-line ART regimens before April 2010 consisted of stavudine or zidovudine with lamivudine and either efavirenz or nevirapine. Tenofovir and/or abacavir was substituted for stavudine after April 2010 in first-line ART. We evaluated the frequency and type of single-drug substitutions, treatment interruptions, and switches to second-line therapy. Fine and Gray competing risk regression models were used to evaluate the association of antiretroviral drug type with single-drug substitutions, treatment interruptions, and second-line switches in the first 24-months on treatment. RESULTS: 398 (15.3%) single-drug substitutions, 187 (7.2%) treatment interruptions and 86 (3.3%) switches to second-line therapy occurred among 2602 pediatric patients over 24-months on ART. Overall, the rate of single-drug substitutions started to increase in 2009, peaked in 2011 at 25%, then declined to 10% in 2013, well after the integration of tenofovir into pediatric regimens; no patients over the age of 3 were initiated on abacavir for first-line therapy. Competing risk regression models showed patients on zidovudine or stavudine had upwards of a 5-fold increase in single-drug substitution vs. patients initiated on tenofovir in the first 24-months on ART. Older adolescents also had a 2-3-fold increase in treatment interruptions and switches to second-line therapy compared to younger patients in the first 24-months on ART. CONCLUSIONS: The decline in single-drug substitutions is associated with introduction of tenofovir. Tenofovir use could improve regimen durability and treatment outcomes in resource-limited settings

Strategies and Interventions for Increasing Homework Completion and Accuracy

This four part thesis contains: Analytic review of literature of the work of a number of authors and researchers who discuss strategies and interventions aimed at improving students\u27 homework completion and accuracy rates. Discussion of the specific roles that students, parents, and families play and the contributions of teachers when it comes to homework. It will discuss a variety of ways that teachers can encourage students to complete their homework and do so with accuracy. A discussion of the implications for teachers including the pros and cons of several interventions. The limitations of the review and several recommendations for future research

Strategies and Interventions for Increasing Homework Completion and Accuracy

Abstract provided by repository to aid in discovery process.This four part thesis contains: Analytic review of literature of the work of a number of authors and researchers who discuss strategies and interventions aimed at improving students' homework completion and accuracy rates. Discussion of the specific roles that students, parents, and families play and the contributions of teachers when it comes to homework. It will discuss a variety of ways that teachers can encourage students to complete their homework and do so with accuracy. A discussion of the implications for teachers including the pros and cons of several interventions. The limitations of the review and several recommendations for future research.SUNY BrockportEducation and Human DevelopmentMaster of Science in Education (MSEd)Education and Human Development Master's These

Heuristics in exploration: Distributional information is selectively used for activelearning

Everyday decision-making is filled with choices about what to act on, with outcomes playing a critical role in learn-ing. Information gain is oft cited as a valuable approach to maximize potential learning, but its computation is costly. It entailsevaluating the probability of multiple outcomes given any possible action, and then considering the degree of belief-change overall possibilities. Given the computational complexity of this evaluation, it becomes important to ask whether learners employcues to information gain; are there heuristics that drive choice in active learning? Our experiments ask participants to choosebetween two options (varying in distributional characteristics) in either a “learning-condition” or “collecting-condition”. Ourresults suggest that adults are sensitive to cues (e.g. variance) that tend to correlate with information gain. These cues areonly favored in learning-goal contexts, suggesting that certain distributional qualities are not always appealing, but rather areselectively-employed heuristics towards information gain

The Search for Invariance: Repeated Positive Testing Serves the Goals of Causal Learning

Positive testing is characteristic of exploratory behavior, yet it seems to be at odds with the aim of information seeking. After all, repeated demonstrations of one’s current hypothesis often produce the same evidence and fail to distinguish it from potential alternatives. Research on the development of scientific reasoning and adult rule learning have both documented and attempted to explain this behavior. The current chapter reviews this prior work and introduces a novel theoretical account—the Search for Invariance (SI) hypothesis—which suggests that producing multiple positive examples serves the goals of causal learning. This hypothesis draws on the interventionist framework of causal reasoning, which suggests that causal learners are concerned with the invariance of candidate hypotheses. In a probabilistic and interdependent causal world, our primary goal is to determine whether, and in what contexts, our causal hypotheses provide accurate foundations for inference and intervention—not to disconfirm their alternatives. By recognizing the central role of invariance in causal learning, the phenomenon of positive testing may be reinterpreted as a rational information-seeking strategy