5,940 research outputs found

    A General Semantics Model for Speech Evaluation

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    Physical Activity Data Use by Technoathletes: Examples of Collection, Inscription, and Identification

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    The proliferation of physical activity data monitoring devices had led to an increase in technoathletes—individuals who combine athletic training and performance with the collection and evaluation of personally-relevant data in an effort to better understand their own abilities. We interviewed 20 technoathletes who were actively involved within either cycling or running communities. Qualitative vignettes of technoathletic engagement with data and the practice of data logging, in specific, are discussed and illustrated. Individual relationships that technoathletes have with their data are also examined. Through the examples, we highlight some commonalities in the data that were obtained and how various athletes represented that information. We also consider some of the tensions that technoathletes have with respect to the data they can obtain and how they saw themselves in light of their data and consider some implications for instruction

    Quantified recess: Design of an activity for elementary students involving analyses of their own movement data

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    Recess is often a time for children in school to engage recreationally in physically demanding and highly interactive activities with their peers. This paper describes a design effort to encourage fifth-grade students to examine sensitivities associated with different measures of center by having them analyze activities during recess using over the course of a week using Fitbit activity trackers and TinkerPlots data visualization software. We describe the activity structure some observed student behaviors during the activity. We also provide a descriptive account, based on video records and transcripts, of two students who engaged thoughtfully with their recess data and developed a more sophisticated understanding of when and how outliers affect means and medians

    X-ray Diagnostics of Grain Depletion in Matter Accreting onto T Tauri Stars

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    Recent analysis of high resolution Chandra X-ray spectra has shown that the Ne/O abundance ratio is remarkably constant in stellar coronae. Based on this result, we point out the utility of the Ne/O ratio as a discriminant for accretion-related X-rays from T Tauri stars, and for probing the measure of grain-depletion of the accreting material in the inner disk. We apply the Ne/O diagnostic to the classical T Tauri stars BP Tau and TW Hya--the two stars found to date whose X-ray emission appears to originate, at least in part, from accretion activity. We show that TW Hya appears to be accreting material which is significantly depleted in O relative to Ne. In constrast, BP Tau has an Ne/O abundance ratio consistent with that observed for post-T Tauri stars. We interpret this result in terms of the different ages and evolutionary states of the circumstellar disks of these stars. In the young BP Tau disk (age 0.6 Myr) dust is still present near the disk corotation radius and can be ionized and accreted, re-releasing elements depleted onto grains. In the more evolved TW Hya disk (age 10 Myr), evidence points to ongoing coagulation of grains into much larger bodies, and possibly planets, that can resist the drag of inward-migrating gas, and accreting gas is consequently depleted of grain-forming elements.Comment: 13 pages, 1 Figure, ApJ Letters, in pres

    Risk factors for ischaemic colitis after surgery for abdominal aortic aneurysm: a systematic review and observational meta-analysis

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    BACKGROUND: Ischaemic colitis is an infrequent but serious complication following repair of abdominal aortic aneurysm (AAA), with high mortality rates. This systematic review set out to identify risk factors for the development of ischaemic colitis after AAA surgery. METHODS: A systematic search of the MEDLINE, EMBASE and CINAHL databases was performed. This search was limited to studies published in the English language after 1990. Abstracts were screened by two authors. Eligible studies were obtained as full text for further examination. Data was extracted by two authors, and any disputes were resolved via consensus. Extracted data was pooled using Mantel-Haenszel random effects models. Bias was assessed using two Cochrane-approved tools. Effect sizes are expressed as relative risk ratios alongside the 95 % confidence interval. Statistical significance was defined at the level of p < 0.05. RESULTS: From 388 studies identified in the initial search, 33 articles were included in the final synthesis and analysis. Risk factors were grouped into patient (female gender, disease severity) and operative factors (peri-procedural hypotension, operative modality). The risk of ischaemic colitis was significantly higher when undergoing emergency repair versus elective (risk ratio (RR) 7.36, 3.08 to 17.58, p < 0.001). Endovascular repair reduced the likelihood of ischaemic colitis (RR 0.22, 0.12 to 0.39, p < 0.001). DISCUSSION: The quality of published evidence on this subject is poor with many retrospective datasets and inconsistent reporting across studies. Despite this, emergency presentation and open repair should prompt close monitoring for the development of IC

    Resource variation in colorectal surgery; a national centre-level analysis.

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    BACKGROUND: Delivery of quality colorectal surgery requires adequate resources. We set out to assess the relationship between resources and outcomes in English colorectal units. METHODS: Data was extracted from the ACPGBI resource questionnaire to profile resources. This was correlated with Hospital Episode Statistics (HES) outcome data including 90-day mortality and readmissions. Patient satisfaction measures were extracted from the Cancer Experience Patient Survey (CEPS) and compared at unit level. Centres were divided by workload into low, middle, and top tertile. RESULTS: Completed questionnaires were received from 75 centres in England. Service resources were similar between low and top tertiles in access to CEPOD theatre, level 2 or 3 beds per 250,000 population or likelihood of having a dedicated colorectal ward. There was no difference in staffing levels per 250,000 unit of population. Each 10% increase in the proportion of cases attempted laparoscopically, was associated with reduced 90-day unplanned readmission (RR 0.94, 95% CI 0.91 to 0.97, p<0.001). The presence of a dedicated colorectal ward (RR 0.85, 95% CI 0.73 to 0.99, p =0.040) was also associated with a significant reduction in unplanned readmissions. There was no association between staffing or service factors and patient satisfaction. DISCUSSION AND CONCLUSIONS: Resource levels do not vary based on unit of population. There is benefit associated with increased use of laparoscopy and a dedicated surgical ward. Alternative measures to assess the relationship between resources and outcome, such as failure to rescue, should be explored in UK practice. This article is protected by copyright. All rights reserved

    Final design report of a personnel launch system and a family of heavy lift launch vehicles

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    The objective was to design both a Personnel Launch System (PLS) and a family of Heavy Lift Launch Vehicles (FHLLVs) that provide low cost and efficient operation in missions not suited for the Shuttle. The PLS vehicle is designed primarily for space station crew rotation and emergency crew return. The final design of the PLS vehicle and its interior is given. The mission of the FHLLVs is to place large, massive payloads into Earth orbit with payload flexibility being considered foremost in the design. The final design of three launch vehicles was found to yield a payload capacity range from 20 to 200 mt. These designs include the use of multistaged, high thrust liquid engines mounted on the core stages of the rocket

    Atrial fibrillation after gastrointestinal surgery: incidence and associated risk factors

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    BACKGROUND: Atrial fibrillation (AF) is a common dysrhythmia that can occur after major physiological stress including surgery (postoperative AF). There are few data on postoperative AF after abdominal surgery. We set out to define the incidence of de novo postoperative AF after abdominal surgery and associated risk factors. METHODS: The Patient History Integrated Data store administrative database was interrogated for patients aged ≥65 y undergoing abdominal surgery from April 2012 to April 2014. Patients with pre-existing AF were excluded. The primary outcome was diagnosis of AF. RESULTS: Two thousand nine hundred and sixty-seven cases were included of whom 187 developed postoperative AF within 90 d (6.3%). The rate of postoperative AF varied by operation and was highest in small bowel resection (17.2%) and lowest in biliary surgery (4.8%). Median time to detection of postoperative AF was 32 d. Patients who developed postoperative AF were significantly older than those who did not develop AF (median age 75.3 y versus 72.4 y, P < 0.01). Logistic regression modeling found increasing age (odds ratio [OR] 1.03 [confidence interval {CI} 1.01-1.06], hypertension OR 1.73 [CI 1.19-2.51]), congestive cardiac failure (OR 3.04 [CI 1.88-4.92], and vascular disease OR 2.29 [CI 1.39-3.37]) were predictive of the development of postoperative AF within 30 d. The area under the curve for this model was 0.733. CONCLUSIONS: Postoperative AF affects a significant number of patients after abdominal surgery. Demographics such as history of cardiovascular disease might aid prediction of postoperative AF. Postoperative AF is mostly identified after discharge, suggesting the need for postoperative screening

    Entropy/IP: Uncovering Structure in IPv6 Addresses

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    In this paper, we introduce Entropy/IP: a system that discovers Internet address structure based on analyses of a subset of IPv6 addresses known to be active, i.e., training data, gleaned by readily available passive and active means. The system is completely automated and employs a combination of information-theoretic and machine learning techniques to probabilistically model IPv6 addresses. We present results showing that our system is effective in exposing structural characteristics of portions of the IPv6 Internet address space populated by active client, service, and router addresses. In addition to visualizing the address structure for exploration, the system uses its models to generate candidate target addresses for scanning. For each of 15 evaluated datasets, we train on 1K addresses and generate 1M candidates for scanning. We achieve some success in 14 datasets, finding up to 40% of the generated addresses to be active. In 11 of these datasets, we find active network identifiers (e.g., /64 prefixes or `subnets') not seen in training. Thus, we provide the first evidence that it is practical to discover subnets and hosts by scanning probabilistically selected areas of the IPv6 address space not known to contain active hosts a priori.Comment: Paper presented at the ACM IMC 2016 in Santa Monica, USA (https://dl.acm.org/citation.cfm?id=2987445). Live Demo site available at http://www.entropy-ip.com
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