Are you really anonymous online? Your friends on Twitter may give you away

As you browse the internet, online advertisers track nearly every site you visit, amassing a trove of information on your habits and preferences. When you visit a news site, they might see you’re a fan of basketball, opera and mystery novels, and accordingly select ads tailored to your tastes. Advertisers use this information to create highly personalized experiences, but they typically don’t know exactly who you are. They observe only your digital trail, not your identity itself, and so you might feel that you’ve retained a degree of anonymity

Arithmetic of Potts Model Hypersurfaces

We consider Potts model hypersurfaces defined by the multivariate Tutte polynomial of graphs (Potts model partition function). We focus on the behavior of the number of points over finite fields for these hypersurfaces, in comparison with the graph hypersurfaces of perturbative quantum field theory defined by the Kirchhoff graph polynomial. We give a very simple example of the failure of the "fibration condition" in the dependence of the Grothendieck class on the number of spin states and of the polynomial countability condition for these Potts model hypersurfaces. We then show that a period computation, formally similar to the parametric Feynman integrals of quantum field theory, arises by considering certain thermodynamic averages. One can show that these evaluate to combinations of multiple zeta values for Potts models on polygon polymer chains, while silicate tetrahedral chains provide a candidate for a possible occurrence of non-mixed Tate periods

Conditional protein degradation in Yarrowia lipolytica using the auxin-inducible degron

Conditional protein degradation is a powerful tool for controlled protein knockdown. The auxin-inducible degron (AID) technology uses a plant auxin to induce depletion of degron-tagged proteins, and it has been shown to be functional in several non-plant eukaryotes. In this study, we demonstrated AID-based protein knockdown in an industrially important oleaginous yeas

A new approach to the chronology of caves 268/272/275 in the Dunhuang Mogao Grottoes: combining radiocarbon dates and archaeological information within a Bayesian statistical framework

The construction chronology of three of the earliest Dunhuang Mogao Grottoes (Caves 268, 272, and 275) has been the subject of ongoing debate for over half a century. This chronology is a crucial topic in terms of further understanding of the establishment of the Dunhuang Mogao Grottoes, early Buddhism in the Gansu corridor, and its relationship with Buddhism developed in the Central Plains. Building upon archaeological, art historical and radiocarbon (14C) dating studies, we integrate new 14C data with these previously published findings utilizing Bayesian statistical modeling to improve the chronological resolution of this issue. Thus, we determine that all three of these caves were constructed around AD 410–440, suggesting coeval rather than sequential construction

An Experimental Study of Structural Diversity in Social Networks

Several recent studies of online social networking platforms have found that adoption rates and engagement levels are positively correlated with structural diversity, the degree of heterogeneity among an individual's contacts as measured by network ties. One common theory for this observation is that structural diversity increases utility, in part because there is value to interacting with people from different network components on the same platform. While compelling, evidence for this causal theory comes from observational studies, making it difficult to rule out non-causal explanations. We investigate the role of structural diversity on retention by conducting a large-scale randomized controlled study on the Twitter platform. We first show that structural diversity correlates with user retention on Twitter, corroborating results from past observational studies. We then exogenously vary structural diversity by altering the set of network recommendations new users see when joining the platform; we confirm that this design induces the desired changes to network topology. We find, however, that low, medium, and high structural diversity treatment groups in our experiment have comparable retention rates. Thus, at least in this case, the observed correlation between structural diversity and retention does not appear to result from a causal relationship, challenging theories based on past observational studies.Comment: To appear in the Proceedings of International AAAI Conference on Web and Social Media (ICWSM 2020

Design of β-hairpins and β-sheets for Molecular Recognition

Protein-nucleic acid interactions are essential in a multitude of biological processes. Protein interactions with single-stranded DNA are particularly important in DNA replication, repair, and telomere regulation. Previously, our laboratory had designed a β-hairpin dimer, (WKWK)2 which binds ssDNA with a Kd of 3 μM and dsDNA with a Kd of 5 μM. These results later led to the redesign of a β-sheet peptide from a native protein which displayed 10-fold selectivity for dsDNA but overall lower affinity for ssDNA at a Kd of 20 μM. In this work, with the insight gained from these studies, a third de novo β-sheet was designed, S123. This new system was found to bind ssDNA with a dissociation constant of 170 nM. Several derivatives were investigated to determine the origins of the marked improvement in binding affinity. It was found that high β-sheet structure was necessary to achieve the observed nanomolar affinity of S123 to ssDNA. In another study, the use of the copper(I)-assisted azide-alkyne cycloaddition as a method of β-hairpin stabilization was investigated at several different positions. It was determined that the CuAAC reaction was a suitable method for locking in β-hairpin structure in peptides possessing the type I' turn, VNGO and the type II' turn, VpGO. All cyclic variants exhibited improved thermal stability and resistance to proteolysis as compared to the non-cyclic peptides. Additionally, the function of the CuAAC cyclized peptides was not altered as exhibited by similar binding affinities for ATP as the WKWK peptide. These studies provided a comprehensive method for CuAAC cyclization of β-hairpin peptides, which could further be utilized in the inhibition of protein-protein interactions.Doctor of Philosoph

Perspectives on certification of community health workers: A statewide mixed-methods assessment in Nebraska

Objectives: While the Community Health Worker (CHW) workforce in the United States has been growing, so far only 19 states certify CHWs. This study sought to identify perspectives on CHW certification among stakeholders in Nebraska, a state that has not established official certification for CHWs yet. Design: A concurrent triangulation mixed methods design. Sample: Study data came from a survey of 142CHWs in Nebraska and interviews with 8 key informants employing CHWs conducted in 2019. Methods: Logistic regression was used to identify significant factors associated with favoring CHW certification, supplemented by thematic analysis of qualitative data fromCHWs and key informants. Results: The majority (84%) of CHWs were in favor of a statewide CHW certification in Nebraska, citing community benefits, workforce validation, and standardization of knowledge as the main reasons. Participant characteristics associated with favoring CHW certification included younger age, racial minority, foreign born, education lower than bachelor’s degree, volunteering as a CHW, and employed for less than 5 years as a CHW. Key informants employing CHWs were divided in whether Nebraska should develop a state certification program. Conclusions: While most CHWs in Nebraska wanted to have a statewide certification program, employers of CHWs were less sure of the need for certification