44 research outputs found

    Frameup: An Incriminatory Attack on Storj: A Peer to Peer Blockchain Enabled Distributed Storage System

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    In this work we present a primary account of frameup, an incriminatory attack made possible because of existing implementations in distributed peer to peer storage. The frameup attack shows that an adversary has the ability to store unencrypted data on the hard drives of people renting out their hard drive space. This is important to forensic examiners as it opens the door for possibly framing an innocent victim. Our work employs Storj as an example technology, due to its popularity and market size. Storj is a blockchain enabled system that allows people to rent out their hard drive space to other users around the world by employing a cryptocurrency token that is used to pay for the services rendered. It uses blockchain features like a transaction ledger, public/private key encryption, and cryptographic hash functions – but this work is not centered around blockchain. Our work discusses two frameup attacks, a preliminary and an optimized attack, both of which take advantage of Storj\u27s implementation. Results illustrate that Storj allows a potential adversary to store incriminating unencrypted files, or parts of files that are viewable on people\u27s systems when renting out their unused hard drive space. We offer potential solutions to mitigate our discovered attacks, a developed tool to review if a person has been a victim of a frameup attack, and a mechanism for showing that the files were stored on a hard drive without the renter\u27s knowledge. Our hope is that this work will inspire future security and forensics research directions in the exploration of distributed peer to peer storage systems that embrace blockchain and cryptocurrency tokens

    Preseason And Post Season Body Composition Does Not Change Relative To Playing Time In Division I Female Basketball Players

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    International Journal of Exercise Science 6(3) : 208-216, 2013. The purpose of the study was to determine if preseason and postseason body fat percentages (BF%) change relative to playing time in Division I women’s basketball players. Subjects for the study included 11 National Collegiate Athletic Association (NCAA) Division I female collegiate basketball athletes over the age of 18 from a Midwest public university. Demographic data of each subject (age 20.09 +1.81 yrs., weight 71.13 +10.85 kg., height 176.48 + 8.33 cm.) was taken before the initial body fat assessment. The subjects underwent preseason and postseason BOD POD® testing to get an accurate measure of body fat percentages. Data analyses looked for changes between preseason and postseason body fat percentage. A Pearson’s Correlation was performed to determine if changes in preseason and postseason BF% changed relative to playing time. Body fat percentage varied across preseason and postseason (average decrease in BF%: -1.83%) but such a difference was not significant (t1,10 = 1.89, p = .088). A negative relationship was found between preseason BF% and playing time (r = -.707) and postseason BF% and playing time (r =-.728). No relationship was found between change in BF% and playing time

    Microfluidics: reframing biological enquiry

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    The underlying physical properties of microfluidic tools have led to new biological insights through the development of microsystems that can manipulate, mimic and measure biology at a resolution that has not been possible with macroscale tools. Microsystems readily handle sub-microlitre volumes, precisely route predictable laminar fluid flows and match both perturbations and measurements to the length scales and timescales of biological systems. The advent of fabrication techniques that do not require highly specialized engineering facilities is fuelling the broad dissemination of microfluidic systems and their adaptation to specific biological questions. We describe how our understanding of molecular and cell biology is being and will continue to be advanced by precision microfluidic approaches and posit that microfluidic tools - in conjunction with advanced imaging, bioinformatics and molecular biology approaches - will transform biology into a precision science

    Receipt for payment from John Cocke, Greensboro, Alabama, for Thomas Cocke to Justin E. Beebe, March 28, 1837

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    This document is part of the John Cocke papers that contains the personal, business, and legal papers of this 19th century Marengo County, Alabama, plantation owner, who not only managed his own plantation but also served as an agent for various family members. Financial papers consist of receipts from grocers and suppliers detailing purchases (including slave purchases); account books for his blacksmith shop; and labor accounts with payroll. There are cotton records that contain correspondence as well as accounts

    Recovery of Thumb and Finger Extension and Its Relation to Grasp Performance After Stroke

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    This study investigated how the ability to extend the fingers and thumb recovers early after stroke and how the ability to extend all of the digits affects grasping performance. We studied 24 hemiparetic patients at 3 and 13 wk post stroke. At each visit, we tested the subjects' ability to actively extend all five digits of their contralesional, affected hand against gravity and to perform a grasp movement with the same hand. Three-dimensional motion analysis captured: 1) maximal voluntary extension excursion of each digit and 2) grasp performance variables of movement time, peak aperture, peak aperture rate, and aperture path ratio. We found that finger and thumb extension improved from 3 to 13 wk, with average improvements ranging from 12 to 19° across the five digits. Grasp performance improved on two of the four variables measured. Peak apertures and peak aperture rates improved from 3 to 13 wk, but self-selected movement time and aperture path ratio did not. Stepwise multiple regression models showed that the majority of variance in grasp performance at 13 wk could be predicted by the ability to extend the index or middle finger at 3 wk, plus the change in the ability to extend the index finger from 3 to 13 wk. R2 values ranged from 0.55 to 0.89. Our data indicate that the amount of recovery in finger and thumb extension and grasping is small from 3 to 13 wk post stroke. In people with relatively pure motor hemiparesis, one important factor underlying deficits in hand shaping during grasping is the inability to extend the fingers and thumb. Without sufficient volitional control of finger and thumb extension, successful grasping of objects will not occur

    The effects of an unanticipated side-cut on lower extremity kinematics and ground reaction forces during a drop landing

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    Unanticipated direction to cut after landing may alter the lower extremity landing biomechanics when performing landing motions. These alterations may potentially increase the risk of ACL injury. The purpose of this study was to determine if an unanticipated side-cut affects lower extremity landing biomechanics in females. Eighteen recreational female athletes participated in two blocks of testing: the first block of testing consisted of three acceptable trials of anticipated dominant limb and non-dominant limb 45-degree diagonal cutting after landing, which were performed in a counterbalanced order. The second block of testing consisted of three acceptable trials of unanticipated dominant limb and non-dominant limb diagonal cutting after landing. Data analysis mainly focused on the dominant limb landing biomechanics. Unanticipated side-cut landing, compared (paired t-test, p \u3c 0.05) to the anticipated landings, resulted in less hip abduction and tibial internal rotation angle at initial contact (IC) and a lower maximum ankle inversion angle and a greater maximum knee abduction angle, and knee and hip displacement. Also, greater posterior GRF and a longer time to peak medial GRF were exhibited. These outcomes indicate that athletes may adapt their landing mechanics to land unsafely when encountering an unanticipated event

    High Speed Droplet-based Delivery System for Passive Pumping in Microfluidic Devices

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    A novel microfluidic system has been developed that uses the phenomenon of passive pumping along with a user controlled droplet based fluid delivery system. Passive pumping is the phenomenon by which surface tension induced pressure differences drive fluid movement in closed channels. The automated fluid delivery system consists of a set of voltage controlled valves with micro-nozzles connected to a fluid reservoir and a control system. These voltage controlled valves offer a volumetrically precise way to deliver fluid droplets to the inlet of a microfluidic device in a high frequency manner. Based on the dimensions demonstrated in the current study example, the system is capable of flowing 4 milliliters per minute (through a 2.2mm by 260um cross-sectional channel). Based on these same channel dimensions, fluid exchange of a point inside the channel can be achieved in as little as eight milliseconds. It is observed that there is interplay between momentum of the system (imparted by a combination of the droplets created by the valves and the fluid velocity in the channel), and the surface tension of the liquid. Where momentum provides velocity to the fluid flow (or vice-versa), equilibration of surface tension at the inlet provides a sudden stop to any flow. This sudden stop allows the user to control the flow characteristics of the channel and opens the door for a variety of biological applications, ranging anywhere from reagent delivery to drug-cell studies. It is also observed that when nozzles are aimed at the inlet at shallow angles, the droplet momentum can cause additional interesting fluid phenomena, such as mixing of multiple droplets in the inlet

    Avoid or engage? Outcomes of graded exposure in youth with chronic pain using a sequential replicated single-case randomized design

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    Pain-related fear is typically associated with avoidance behavior and pain-related disability in youth with chronic pain. Youth with elevated pain-related fear have attenuated treatment responses, thus targeted treatment is highly warranted. Evidence supporting graded in-vivo exposure treatment (GET) for adults with chronic pain is considerable, but just emerging for youth. The current investigation represents the first sequential replicated and randomized single-case experimental phase design with multiple measures evaluating GET for youth with chronic pain, entitled GET Living. A cohort 27 youth (81% female) with mixed chronic pain completed GET Living. For each participant, a no-treatment randomized baseline period was compared with GET Living and 3- and 6-month follow-ups. Daily changes in primary outcomes fear and avoidance and secondary outcomes pain catastrophizing, pain intensity, and pain acceptance were assessed using electronic diaries and subjected to descriptive and model-based inference analyses (MLM). Based on individual effect size calculations, a third of participants significantly improved by the end of treatment on fear, avoidance, and pain acceptance. By follow-up over 80% of participants had improved across all primary and secondary outcomes. MLM results to examine the series of replicated cases were generally consistent. Improvements during GET Living was superior to the no-treatment randomized baseline period for avoidance, pain acceptance, and pain intensity, whereas fear and pain catastrophizing did not improve. All five outcomes emerged as significantly improved at 3-and 6-month follow-up. The results of this replicated SCED support the effectiveness of graded exposure for youth with chronic pain and elevated pain-related fear avoidance.status: publishe
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