DeePhy: On Deepfake Phylogeny

Deepfake refers to tailored and synthetically generated videos which are now prevalent and spreading on a large scale, threatening the trustworthiness of the information available online. While existing datasets contain different kinds of deepfakes which vary in their generation technique, they do not consider progression of deepfakes in a "phylogenetic" manner. It is possible that an existing deepfake face is swapped with another face. This process of face swapping can be performed multiple times and the resultant deepfake can be evolved to confuse the deepfake detection algorithms. Further, many databases do not provide the employed generative model as target labels. Model attribution helps in enhancing the explainability of the detection results by providing information on the generative model employed. In order to enable the research community to address these questions, this paper proposes DeePhy, a novel Deepfake Phylogeny dataset which consists of 5040 deepfake videos generated using three different generation techniques. There are 840 videos of one-time swapped deepfakes, 2520 videos of two-times swapped deepfakes and 1680 videos of three-times swapped deepfakes. With over 30 GBs in size, the database is prepared in over 1100 hours using 18 GPUs of 1,352 GB cumulative memory. We also present the benchmark on DeePhy dataset using six deepfake detection algorithms. The results highlight the need to evolve the research of model attribution of deepfakes and generalize the process over a variety of deepfake generation techniques. The database is available at: http://iab-rubric.org/deephy-databaseComment: Accepted at 2022, International Joint Conference on Biometrics (IJCB 2022

Handling Location Uncertainty in Event Driven Experimentation

Singapore National Research Foundation under International Research Centre @ Singapore Funding Initiativ

myDeal: A Mobile Shopping Assistant Matching User Preferences to Promotions

National Research Foundation (NRF) Singapore under International Research Centre @ Singapore Funding Initiativ

myDeal: The Context-Aware Urban Shopping Assistant

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"Any Little Thing of Help": A Qualitative Analysis of the Challenges of Navigating WIC in Chicago and the Roots of Unenrollment

This research project seeks to understand why coverage rates (percentage of eligible individuals that are enrolled) for the Special Supplemental Nutrition Program for Women, Infants, and Children, aka the food assistance program WIC, are so low in Illinois— at 41.8 percent in 2017 compared to the national average of 51.1 percent— and what is causing mothers to unenroll or not enroll at all. Using the city of Chicago as a case study for this issue, this paper will describe the barriers to obtaining and maintaining WIC benefits that low-income mothers face under Chicago’s paper colored coupon system that provides a fundamentally different benefits experience to North Side versus South and West Side residents of the city. In particular, this study will uncover the disparities between mothers’ access to WIC and the challenges they face in obtaining and maintaining their benefits. I will elaborate on ways that WIC can improve in the future to be more accessible to mothers, and ways in which the coming transition to an electronic benefits system (EBT) across the country might aid in creating a benefits process that is easier to navigate. Extensive semi-structured interview data is used in this study to highlight both the experiences of those that are directly affected by WIC enrollment, i.e. low-income mothers, as well as the expertise of those who are practitioners and scholars in the field of public benefits. It is concluded that WIC’s time, resource, and safety demands on low-income mothers is a significant barrier to initial and continued enrollment for many, and that the stakes could not be higher for mothers and their children. In order to create a more accessible system, WIC must make efforts to reduce the restrictions around WIC and increase the flexibility of the program to ease the navigation of this complicated public benefits system, already fraught with many bureaucratic barriers

Activation in isolation : exposure of the actin-binding site in the C-terminal half of gelsolin does not require actin

Gelsolin requires activation to carry out its severing and capping activities on F-actin. Here, we present the structure of the isolated C-terminal half of gelsolin (G4-G6) at 2.0 A resolution in the presence of Ca(2+) ions. This structure completes a triptych of the states of activation of G4-G6 that illuminates its role in the function of gelsolin. Activated G4-G6 displays an open conformation, with the actin-binding site on G4 fully exposed and all three type-2 Ca(2+) sites occupied. Neither actin nor the type-l Ca(2+), which normally is sandwiched between actin and G4, is required to achieve this conformation

Protein crystals can be incommensurately modulated

For a normal periodic crystal, the X-ray diffraction pattern can be described by an orientation matrix and a set of three integers that indicate the reciprocal lattice points. Those integers determine the spacing along the reciprocal lattice directions. In aperiodic crystals, the diffraction pattern is modulated and the standard periodic main reflections are surrounded by satellite reflections. The successful indexing and refinement of the main unit cell and q vector using TWINSOLVE, developed by Svensson [(2003). Lund University, Sweden], are reported here for an incommensurately modulated, aperiodic crystal of a profilin: actin complex. The indexing showed that the modulation is along the b direction in the crystal, which corresponds to an 'actin ribbon' formed by the crystal lattice. Interestingly, the transition to the aperiodic state was shown to be reversible and the diffraction pattern returned to the periodic state during data collection. It is likely that the protein underwent a conformational change that affected the neighbouring profilin: actin molecules in such a way as to produce the observed modulation in the diffraction pattern. Future work will aim to trap the incommensurately modulated crystal state, for example using cryocooling or chemical crosslinking, thus allowing complete X-ray data to be collected

Structural and biochemical rationale for Beta variant protein booster vaccine broad cross-neutralization of SARS-CoV-2

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the COVID-19 pandemic, uses a surface expressed trimeric spike glycoprotein for cell entry. This trimer is the primary target for neutralizing antibodies making it a key candidate for vaccine development. During the global pandemic circulating variants of concern (VOC) caused several waves of infection, severe disease, and death. The reduced efficacy of the ancestral trimer-based vaccines against emerging VOC led to the need for booster vaccines. Here we present a detailed characterization of the Sanofi Beta trimer, utilizing cryo-EM for structural elucidation. We investigate the conformational dynamics and stabilizing features using orthogonal SPR, SEC, nanoDSF, and HDX-MS techniques to better understand how this antigen elicits superior broad neutralizing antibodies as a variant booster vaccine. This structural analysis confirms the Beta trimer preference for canonical quaternary structure with two RBD in the up position and the reversible equilibrium between the canonical spike and open trimer conformations. Moreover, this report provides a better understanding of structural differences between spike antigens contributing to differential vaccine efficacy