Quantification of De-anonymization Risks in Social Networks

The risks of publishing privacy-sensitive data have received considerable attention recently. Several de-anonymization attacks have been proposed to re-identify individuals even if data anonymization techniques were applied. However, there is no theoretical quantification for relating the data utility that is preserved by the anonymization techniques and the data vulnerability against de-anonymization attacks. In this paper, we theoretically analyze the de-anonymization attacks and provide conditions on the utility of the anonymized data (denoted by anonymized utility) to achieve successful de-anonymization. To the best of our knowledge, this is the first work on quantifying the relationships between anonymized utility and de-anonymization capability. Unlike previous work, our quantification analysis requires no assumptions about the graph model, thus providing a general theoretical guide for developing practical de-anonymization/anonymization techniques. Furthermore, we evaluate state-of-the-art de-anonymization attacks on a real-world Facebook dataset to show the limitations of previous work. By comparing these experimental results and the theoretically achievable de-anonymization capability derived in our analysis, we further demonstrate the ineffectiveness of previous de-anonymization attacks and the potential of more powerful de-anonymization attacks in the future.Comment: Published in International Conference on Information Systems Security and Privacy, 201

Secure Pick Up: Implicit Authentication When You Start Using the Smartphone

We propose Secure Pick Up (SPU), a convenient, lightweight, in-device, non-intrusive and automatic-learning system for smartphone user authentication. Operating in the background, our system implicitly observes users' phone pick-up movements, the way they bend their arms when they pick up a smartphone to interact with the device, to authenticate the users. Our SPU outperforms the state-of-the-art implicit authentication mechanisms in three main aspects: 1) SPU automatically learns the user's behavioral pattern without requiring a large amount of training data (especially those of other users) as previous methods did, making it more deployable. Towards this end, we propose a weighted multi-dimensional Dynamic Time Warping (DTW) algorithm to effectively quantify similarities between users' pick-up movements; 2) SPU does not rely on a remote server for providing further computational power, making SPU efficient and usable even without network access; and 3) our system can adaptively update a user's authentication model to accommodate user's behavioral drift over time with negligible overhead. Through extensive experiments on real world datasets, we demonstrate that SPU can achieve authentication accuracy up to 96.3% with a very low latency of 2.4 milliseconds. It reduces the number of times a user has to do explicit authentication by 32.9%, while effectively defending against various attacks.Comment: Published on ACM Symposium on Access Control Models and Technologies (SACMAT) 201

Blood Flow and Vascular Conductance Responses to Dynamic Handgrip Exercise in Hispanic American and Non-Hispanic White Women

Hispanic Americans (HA) are the fastest growing ethnic minority in the United States, with disproportionately higher incidence of obesity, hyperlipidemia and type 2 diabetes compared to their non-Hispanic white (NHW) counterparts. As such, the risk of cardiovascular complications is significantly higher in this population, while the underlying mechanisms remain largely unexplored. Alterations in vascular function occur early in cardiovascular diseases and have not been comprehensively studied in the HA population. Previous studies have demonstrated higher flow-mediated dilation (FMD, an index of resting vascular function) in young HA compared to NHW women. However, whether these differences in vasodilation also occur in response to dynamic exercise remains unknown. PURPOSE: We tested the hypothesis that during increasing intensities of rhythmic handgrip exercise, young, healthy HA women would demonstrate greater forearm blood flow and vascular conductance responses compared to age- and weight-matched NHW women. METHODS: Six HA women (20 ± 2 yr; BMI = 21.45 ± 2.2 kg/m2) and 9 NHW women (20 ± 2 yr; BMI = 21.49 ± 2.2 kg/m2) performed rhythmic handgrip exercise for 3 minutes at 15%, 30%, and 45% of their maximum voluntary contraction (MVC). Each exercise bout was separated by at least 10 minutes of rest. Mean arterial pressure (MAP; finger photoplethysmography), heart rate (ECG), and forearm blood flow (FBF; duplex Doppler ultrasound) was measured at rest and during the last minute of rhythmic exercise. Forearm vascular conductance was calculated as FBF/MAP. RESULTS: Baseline FBF (HA: 53.3 ± 7.6 and NHW: 52.4 ± 11.3 ml/min, mean ± SD, p = 0.87), FVC (HA: 0.64 ± 0.09 and NHW: 0.62 ± 0.16 ml/min/mmHg, p = 0.85), MAP (HA: 83.3 ± 3.18 and NHW: 84.75 ± 6.85 mmHg, p = 0.64), and MVC (HA: 53 ± 13 and NHW: 49 ± 6 kg, p = 0.36) were similar between groups. In response to exercise, both groups demonstrated an intensity dependent increase in FBF (%DFBF during 45%: HA= 437± 90% and NHW= 459 ± 162%, p = 0.76) but no significant difference was found between groups (repeated-measures 2-way ANOVA; interaction effect: p = 0.66, intensity effect: p = 0.0001, ethnicity effect: p = 0.73). Similar to FBF, there was no significant difference in FVC responses between groups (%DFVC 45%: HA= 385 ± 110 and NHW= 393 ± 135, p = 0.91). CONCLUSION: Forearm blood flow and vascular conductance responses during increasing intensities of rhythmic handgrip exercise were not different between HA and NHW women

Forearm Vascular Responses to Rhythmic Handgrip Exercise in Young Healthy Hispanic Men

Hispanic American (HA) men have higher prevalence of Type 2 Diabetes (T2D) when compared to Caucasian American (CA) men (15.3% vs 10.8%). Impaired vascular function is a hallmark of T2D, increasing the risk of cardiovascular morbidity and mortality in this clinical population. However, vascular function in the Hispanic population has not been investigated thoroughly. To date, only two studies have examined the resting flow mediated dilation (FMD) and found a higher FMD in young, healthy, HA adults. Whether exercise-induced reactive hyperemia is preserved in HA adults remains unknown. PURPOSE: We tested the hypothesis that young, healthy HA men would have a higher response in forearm blood flow (FBF) and forearm vascular conductance (FVC) when compared to age-matched CA men. METHODS: In young, healthy HA (n = 7, BMI = 25±2 cm/kg2) and CA men (n = 6, BMI = 24±3), FBF (Duplex doppler ultrasound), heart rate (3-lead ECG), and mean arterial pressure (MAP; finger plethysmography) were measured at rest and during rhythmic handgrip exercise performed for 3 min at 15%, 30%, and 45% of their maximum voluntary contraction (MVC). FVC was calculated by FBF/MAP. Lean muscle mass was measured via dual-energy X-ray absorptiometry (DEXA). RESULTS: Baseline MAP (HA: 85±7 mmHg, CA: 84±7, Mean ± SD, p = 0.85), and MVC (HA: 74 ± 18 kg, CA: 80 ± 17, p = 0.51) were not significantly different between the groups at baseline. Baseline FBF (HA: 83.9±21.9 mL/min, CA: 135.5±39.7, p\u3c0.05) and FVC (HA: 1.0 ± 0.3 mL/min/mmHg, CA: 1.6 ± 0.5, p \u3c 0.05) were significantly greater in CA when compared to HA. In both groups, an intensity dependent increase in FBF and FVC was observed with a significant ethnicity effect between the groups but no significant interaction effect (repeated-measures 2-way ANOVA; interaction effect: p = 0.63, intensity effect: p \u3c 0.01, ethnicity effect: p = 0.006). For example, increase in FVC from baseline (%DFVC) at 45% MVC in HA men was 442 ± 82%, compared to 311 ± 97% CA men, with similar increases in MAP from baseline (45% MVC DMAP; HA: 15 ± 12, CA: 7 ± 5, p = 0.17) or lean muscle mass (HA: 57 ± 4 kg, CA: 61 ± 9 kg, p = 0.41). CONCLUSION: Our preliminary data indicate a higher forearm blood flow and vascular conductance response in response to rhythmic handgrip in HA men compared to matched CA men

Generation of Long-Lived Isomeric States via Bremsstrahlung Irradiation

A method to generate long-lived isomeric states effectively for Mossbauer applications is reported. We demonstrate that this method is better and easier to provide highly sensitive Mossbauer effect of long-lived isomers (>1ms) such as 103Rh. Excitation of (gamma,gamma) process by synchrotron radiation is painful due mainly to their limited linewidth. Instead,(gamma,gamma') process of bremsstrahlung excitation is applied to create these long-lived isomers. Isomers of 45Sc, 107Ag, 109Ag, and 103Rh have been generated from this method. Among them, 103Rh is the only one that we have obtained the gravitational effect at room temperature.Comment: ICAME 05 conference repor

COVCOG 1: Factors Predicting Physical, Neurological and Cognitive Symptoms in Long COVID in a Community Sample. A First Publication From the COVID and Cognition Study

Since its first emergence in December 2019, coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has evolved into a global pandemic. Whilst often considered a respiratory disease, a large proportion of COVID-19 patients report neurological symptoms, and there is accumulating evidence for neural damage in some individuals, with recent studies suggesting loss of gray matter in multiple regions, particularly in the left hemisphere. There are a number of mechanisms by which COVID-19 infection may lead to neurological symptoms and structural and functional changes in the brain, and it is reasonable to expect that many of these may translate into cognitive problems. Indeed, cognitive problems are one of the most commonly reported symptoms in those experiencing “Long COVID”—the chronic illness following COVID-19 infection that affects between 10 and 25% of patients. The COVID and Cognition Study is a part cross-sectional, part longitudinal, study documenting and aiming to understand the cognitive problems in Long COVID. In this first paper from the study, we document the characteristics of our sample of 181 individuals who had experienced COVID-19 infection, and 185 who had not. We explore which factors may be predictive of ongoing symptoms and their severity, as well as conducting an in-depth analysis of symptom profiles. Finally, we explore which factors predict the presence and severity of cognitive symptoms, both throughout the ongoing illness and at the time of testing. The main finding from this first analysis is that that severity of initial illness is a significant predictor of the presence and severity of ongoing symptoms, and that some symptoms during the initial illness—particularly limb weakness—may be more common in those that have more severe ongoing symptoms. Symptom profiles can be well described in terms of 5 or 6 factors, reflecting the variety of this highly heterogenous condition experienced by the individual. Specifically, we found that neurological/psychiatric and fatigue/mixed symptoms during the initial illness, and that neurological, gastrointestinal, and cardiopulmonary/fatigue symptoms during the ongoing illness, predicted experience of cognitive symptoms.</jats:p

COVCOG 2: Cognitive and Memory Deficits in Long COVID: A Second Publication From the COVID and Cognition Study.

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been often characterized as a respiratory disease. However, it is increasingly being understood as an infection that impacts multiple systems, and many patients report neurological symptoms. Indeed, there is accumulating evidence for neural damage in some individuals, with recent studies suggesting loss of gray matter in multiple regions, particularly in the left hemisphere. There are several mechanisms by which the COVID-19 infection may lead to neurological symptoms and structural and functional changes in the brain, and cognitive problems are one of the most commonly reported symptoms in those experiencing Long COVID - the chronic illness following the COVID-19 infection that affects between 10 and 25% of patients. However, there is yet little research testing cognition in Long COVID. The COVID and Cognition Study is a cross-sectional/longitudinal study aiming to understand cognitive problems in Long COVID. The first paper from the study explored the characteristics of our sample of 181 individuals who had experienced the COVID-19 infection, and 185 who had not, and the factors that predicted ongoing symptoms and self-reported cognitive deficits. In this second paper from the study, we assess this sample on tests of memory, language, and executive function. We hypothesize that performance on "objective" cognitive tests will reflect self-reported cognitive symptoms. We further hypothesize that some symptom profiles may be more predictive of cognitive performance than others, perhaps giving some information about the mechanism. We found a consistent pattern of memory deficits in those that had experienced the COVID-19 infection, with deficits increasing with the severity of self-reported ongoing symptoms. Fatigue/Mixed symptoms during the initial illness and ongoing neurological symptoms were predictive of cognitive performance

Functional diversification of Argonautes in nematodes:an expanding universe

In the last decade, many diverse RNAi (RNA interference) pathways have been discovered that mediate gene silencing at epigenetic, transcriptional and post-transcriptional levels. The diversity of RNAi pathways is inherently linked to the evolution of Ago (Argonaute) proteins, the central protein component of RISCs (RNA-induced silencing complexes). An increasing number of diverse Agos have been identified in different species. The functions of most of these proteins are not yet known, but they are generally assumed to play roles in development, genome stability and/or protection against viruses. Recent research in the nematode Caenorhabditis elegans has expanded the breadth of RNAi functions to include transgenerational epigenetic memory and, possibly, environmental sensing. These functions are inherently linked to the production of secondary siRNAs (small interfering RNAs) that bind to members of a clade of WAGOs (worm-specific Agos). In the present article, we review briefly what is known about the evolution and function of Ago proteins in eukaryotes, including the expansion of WAGOs in nematodes. We postulate that the rapid evolution of WAGOs enables the exceptional functional plasticity of nematodes, including their capacity for parasitism