What Storage Access Privacy is Achievable with Small Overhead?

Oblivious RAM (ORAM) and private information retrieval (PIR) are classic cryptographic primitives used to hide the access pattern to data whose storage has been outsourced to an untrusted server. Unfortunately, both primitives require considerable overhead compared to plaintext access. For large-scale storage infrastructure with highly frequent access requests, the degradation in response time and the exorbitant increase in resource costs incurred by either ORAM or PIR prevent their usage. In an ideal scenario, a privacy-preserving storage protocols with small overhead would be implemented for these heavily trafficked storage systems to avoid negatively impacting either performance and/or costs. In this work, we study the problem of the best $\mathit{storage\ access\ privacy}$that is achievable with only$\mathit{small\ overhead}$over plaintext access. To answer this question, we consider$\mathit{differential\ privacy\ access}$which is a generalization of the$\mathit{oblivious\ access}$security notion that are considered by ORAM and PIR. Quite surprisingly, we present strong evidence that constant overhead storage schemes may only be achieved with privacy budgets of$\epsilon = \Omega(\log n)$. We present asymptotically optimal constructions for differentially private variants of both ORAM and PIR with privacy budgets$\epsilon = \Theta(\log n)$with only$O(1)$overhead. In addition, we consider a more complex storage primitive called key-value storage in which data is indexed by keys from a large universe (as opposed to consecutive integers in ORAM and PIR). We present a differentially private key-value storage scheme with$\epsilon = \Theta(\log n)$and$O(\log\log n)$ overhead. This construction uses a new oblivious, two-choice hashing scheme that may be of independent interest.Comment: To appear at PODS'1

Characterization of Endothelial Nitric Oxide Synthase Serine-600 Phosphorylation

Endothelial nitric oxide synthase (eNOS) is part of a family of three nitric oxide synthase (NOS) enzymes that catalyze the production of nitric oxide (NO). NO is a gaseous, free-radical signaling molecule that has a variety of cellular and physiological functions that range from maintaining cardiovascular homeostasis to neurotransmission. The function of NO greatly depends on the concentration and is cell type specific. eNOS is the most regulated of the three NOS isoforms and the mechanisms of regulation can be through protein-protein interactions and posttranslational modifications. A connection with eNOS and the cell cycle has begun to form with recent research identifying eNOS as a substrate of cyclin-dependent kinases (CDK). CDKs are one of the regulatory elements in cell cycle progression and form a class of serine/threonine kinases. The most commonly studied and well understood posttranslational modification of eNOS is phosphorylation. This work builds on our laboratory’s discovery of a phosphorylation site – ser600 – on the autoinhibitory loop of eNOS. Our work finds a novel connection between phosphorylation at this site and mitosis

Sortilin: A Protein Involved in Ldl Metabolism and Atherosclerosis

Genome-wide association studies (GWAS) have been used to identify novel genes and loci that contribute to lipid traits and coronary heart disease (CHD) in a causal manner. A locus on chromosome 1p13, which harbors the gene sortilin-1 (SORT1) encoding the protein sortilin is the locus in the human genome with the strongest association with low-density lipoprotein cholesterol (LDL-C) and is also one of the strongest loci associated with CHD. Homozygosity for the minor allele haplotype at 1p13 is associated with a \u3e10 fold increase in hepatic SORT1 expression, a mean 16 mg/dL reduction in plasma LDL-C, and a 40% reduction in CHD risk. Sortilin has been extensively studied in the central nervous system, where it traffics multiple ligands from the Golgi apparatus to the lysosome and also serves as a cell surface endocytosis receptor for a variety of ligands. However, the role of sortilin in other cell types, most notably hepatocytes and macrophages, which are key regulators of lipid metabolism and atherosclerosis development, has not been well studied. Through a series of overexpression and mutagenesis studies in cells and mice, the Rader lab has previously shown that increased sortilin expression in liver reduces plasma LDL-C both by promoting the presecretory lysosomal degradation of the LDL precursor very-low density lipoprotein (VLDL) and by serving as an endocytosis receptor for LDL. The Rader lab has also shown that total body Sort1 deficiency is associated with compromised LDL clearance consistent with overexpression studies; however, it is also associated with a paradoxical reduction in VLDL secretion. Using a variety of liver specific Sort1 deficiency models, as well as reconstitution and mutagenesis studies, I showed that liver specificity is not responsible for the secretion paradox and instead demonstrated that sortilin plays a dual role in VLDL trafficking, serving as a chaperone that facilitates VLDL secretion as well as a transporter that promotes the presecretory degradation of VLDL, depending on the conditions and level of sortilin expression. Sortilin is strongly associated both with LDL-C levels and with CHD/atherosclerosis. Atherosclerotic cardiovascular disease is driven by elevated LDL-C, thus it is tempting to speculate that the strong association of the SORT1 locus with atherosclerosis is due solely to the LDL-C association. Because sortilin is expressed in macrophages, I hypothesized that macrophage sortilin might influence atherogenesis. Through careful interrogation of the role of sortilin in macrophages, I demonstrated that sortilin plays a role in the development of atherosclerosis independent of plasma LDL-C levels. Specifically, I showed that sortilin serves as an endocytosis receptor for LDL on macrophages, and this represents a physiologically important pathway by which LDL cholesterol enters macrophages and contributes to foam cell formation and atherosclerosis. This work increases our understanding of the role of hepatic and macrophage sortilin in LDL metabolism and atherogenesis, and provides insight into the relationship of the SORT1 locus with LDL-C levels and CHD risk

Are Word Embedding-based Features Useful for Sarcasm Detection?

This paper makes a simple increment to state-of-the-art in sarcasm detection research. Existing approaches are unable to capture subtle forms of context incongruity which lies at the heart of sarcasm. We explore if prior work can be enhanced using semantic similarity/discordance between word embeddings. We augment word embedding-based features to four feature sets reported in the past. We also experiment with four types of word embeddings. We observe an improvement in sarcasm detection, irrespective of the word embedding used or the original feature set to which our features are augmented. For example, this augmentation results in an improvement in F-score of around 4\% for three out of these four feature sets, and a minor degradation in case of the fourth, when Word2Vec embeddings are used. Finally, a comparison of the four embeddings shows that Word2Vec and dependency weight-based features outperform LSA and GloVe, in terms of their benefit to sarcasm detection.Comment: The paper will be presented at Conference on Empirical Methods in Natural Language Processing (EMNLP) 2016 in November 2016. http://www.emnlp2016.net

Does Acute Exercise Improve Driving Performance In Patients With Untreated Sleep Apnea?

poster abstractDecreased awareness among drivers with obstructive sleep apnea (OSA), a condition in which the airflow decreases during breathing, has been shown to increase motor vehicular crash risk. Those who suffer from OSA have been found to have between a two and tenfold increase of accident risk due to feelings of fatigue resulting from fragmented sleep (George, C.F.P. 2007). Treatment using continuous positive airway pressure (CPAP) has shown mixed effects in improving driver performance (Vkaulin, et al., 2011). Therefore, our objective is to determine if acute aerobic exercise (i.e. walking) prior to driving for patients with OSA can reduce the amount of accidents. Patients with OSA that are awaiting sleep apnea treatment will first undergo a ten minute moderate-intensity exercise session and then use a high fidelity driving simulator for the next fifteen minutes. A nighttime countryside scenario with two naturalistic obstacles at random times will be used. While the subject is driving, the simulator will record lane deviation, collision events, and braking response time. The same subjects will also test the simulator without doing any exercise in order to determine if there was any benefit from the exercise. The order of the simulator sessions, both with and without exercise, will be randomized to prevent practice effect. We hope to see improved driving behavior when the subjects undergo a ten minute aerobic exercise prior to driving

Responses to intensity-shifted auditory feedback during running speech

PURPOSE: Responses to intensity perturbation during running speech were measured to understand whether prosodic features are controlled in an independent or integrated manner. METHOD: Nineteen English-speaking healthy adults (age range = 21-41 years) produced 480 sentences in which emphatic stress was placed on either the 1st or 2nd word. One participant group received an upward intensity perturbation during stressed word production, and the other group received a downward intensity perturbation. Compensations for perturbation were evaluated by comparing differences in participants' stressed and unstressed peak fundamental frequency (F0), peak intensity, and word duration during perturbed versus baseline trials. RESULTS: Significant increases in stressed-unstressed peak intensities were observed during the ramp and perturbation phases of the experiment in the downward group only. Compensations for F0 and duration did not reach significance for either group. CONCLUSIONS: Consistent with previous work, speakers appear sensitive to auditory perturbations that affect a desired linguistic goal. In contrast to previous work on F0 perturbation that supported an integrated-channel model of prosodic control, the current work only found evidence for intensity-specific compensation. This discrepancy may suggest different F0 and intensity control mechanisms, threshold-dependent prosodic modulation, or a combined control scheme.R01 DC002852 - NIDCD NIH HHS; R03 DC011159 - NIDCD NIH HH

Early diffusion evidence of retrograde transsynaptic degeneration in the human visual system

We investigated whether diffusion tensor imaging (DTI) indices of white matter integrity would offer early markers of retrograde transsynaptic degeneration (RTD) in the visual system after stroke Objective: We investigated whether diffusion tensor imaging (DTI) indices of white matter integrity would offer early markers of retrograde transsynaptic degeneration (RTD) in the visual system after stroke. Methods: We performed a prospective longitudinal analysis of the sensitivity of DTI markers of optic tract health in 12 patients with postsynaptic visual pathway stroke, 12 stroke controls, and 28 healthy controls. We examined group differences in (1) optic tract fractional anisotropy (FA-asymmetry), (2) perimetric measures of visual impairment, and (3) the relationship between FA-asymmetry and perimetric assessment. Results: FA-asymmetry was higher in patients with visual pathway lesions than in control groups. These differences were evident 3 months from the time of injury and did not change significantly at 12 months. Perimetric measures showed evidence of impairment in participants with visual pathway stroke but not in control groups. A significant association was observed between FA-asymmetry and perimetric measures at 3 months, which persisted at 12 months. Conclusions: DTI markers of RTD are apparent 3 months from the time of injury. This represents the earliest noninvasive evidence of RTD in any species. Furthermore, these measures associate with measures of visual impairment. DTI measures offer a reproducible, noninvasive, and sensitive method of investigating RTD and its role in visual impairment

CacheShuffle: A Family of Oblivious Shuffles

We consider oblivious two-party protocols where a client outsources N blocks of private data to a server. The client wishes to access the data to perform operations in such a way that the access pattern does not leak information about the data and the operations. In this context, we consider oblivious shuffling with a focus on bandwidth efficient protocols for clients with small local memory. In the shuffling problem, the N outsourced blocks, B_1,...,B_N, are stored on the server according to an initial permutation pi. The client wishes to reshuffle the blocks according to permutation sigma. Oblivious shuffling is a building block in several applications that hide patterns of data access. In this paper, we introduce a generalization of the oblivious shuffling problem, the K-oblivious shuffling problem, and provide bandwidth efficient algorithms for a wide range of client storage requirements. The task of a K-oblivious shuffling algorithm is to shuffle N encrypted blocks that were previously randomly allocated on the server in such a way that an adversarial server learns nothing about either the new allocation of blocks or the block contents. The security guarantee must hold when an adversary has partial information on the initial placement of a subset of K <=N revealed blocks. The notion of oblivious shuffling is obtained for K=N. We first study the N-oblivious shuffling problem and start by presenting CacheShuffleRoot, that is tailored for clients with O(sqrt{N}) blocks of memory and uses approximately 4N blocks of bandwidth. CacheShuffleRoot is a 4x improvement over the previous best known N-oblivious shuffle for practical sizes of N. We then generalize CacheShuffleRoot to CacheShuffle that can be instantiated for any client memory size S and requires O(N log_S N) blocks of bandwidth. Next, we present K-oblivious shuffling algorithms that require 2N + f(K,S) blocks of bandwidth for all K and a wide range of S. Any extra bandwidth above the 2N lower bound depends solely on K and S. Specifically, for clients with O(K) blocks of memory, we present KCacheShuffleBasic that uses exactly 2N blocks of bandwidth. For clients with memory S <= K, we present KCacheShuffle, that requires 2N + O(K log_S K) blocks of bandwidth. Finally, motivated by applications to ORAMs, we consider the case where the server stores D dummy blocks whose contents are irrelevant in addition to the N real blocks. For this case, we design algorithm KCacheShuffleDummy that shuffles N+D blocks with K revealed blocks using O(K) blocks of client storage and approximately D+2N blocks of bandwidth

Architecture of the Short External Rotator Muscles of the Hip.

BackgroundMuscle architecture, or the arrangement of sarcomeres and fibers within muscles, defines functional capacity. There are limited data that provide an understanding of hip short external rotator muscle architecture. The purpose of this study was thus to characterize the architecture of these small hip muscles.MethodsEight muscles from 10 independent human cadaver hips were used in this study (n = 80 muscles). Architectural measurements were made on pectineus, piriformis, gemelli, obturators, quadratus femoris, and gluteus minimus. Muscle mass, fiber length, sarcomere length, and pennation angle were used to calculate the normalized muscle fiber length, which defines excursion, and physiological cross-sectional area (PCSA), which defines force-producing capacity.ResultsGluteus minimus had the largest PCSA (8.29 cm2) followed by obturator externus (4.54 cm2), whereas superior gemellus had the smallest PCSA (0.68 cm2). Fiber lengths clustered into long (pectineus - 10.38 cm and gluteus minimus - 10.30 cm), moderate (obturator internus - 8.77 cm and externus - 8.04 cm), or short (inferior gemellus - 5.64 and superior gemellus - 4.85). There were no significant differences among muscles in pennation angle which were all nearly zero. When the gemelli and obturators were considered as a single functional unit, their collective PCSA (10.00 cm2) exceeded that of gluteus minimus as a substantial force-producing group.ConclusionsThe key findings are that these muscles have relatively small individual PCSAs, short fiber lengths, and low pennation angles. The large collective PCSA and short fiber lengths of the gemelli and obturators suggest that they primarily play a stabilizing role rather than a joint rotating role