761 research outputs found
Multi-rate demodulator architecture
A unique digital multi-rate demodulator (MRD) architecture is presented for onboard satellite communications processing. The multi-rate feature enables the same demodulator hardware to process either one wideband channel (WBC), or process up to thirty-two independent narrowband channels (NBC) that are time division multiplexed (TDM). The MRD can process many quadrature modulation format such as offset quadrature phase shift keying (OQPSK). Possible applications include voice and data transmission for commercial or military users
Obstructive sleep apnea as an independent predictor of postoperative delirium and pain: Protocol for an observational study of a surgical cohort [version 2; referees: 2 approved]
Introduction: Postoperative delirium and pain are common complications in adults, and are difficult both to prevent and treat. Obstructive sleep apnea (OSA) is prevalent in surgical patients, and has been suggested to be a risk factor for postoperative delirium and pain. OSA also might impact pain perception, and alter pain medication requirements. This protocol describes an observational study, with the primary aim of testing whether OSA is an independent predictor of postoperative complications, focusing on (i) postoperative incident delirium and (ii) acute postoperative pain severity. We secondarily hypothesize that compliance with prescribed treatment for OSA (typically continuous positive airway pressure or CPAP) might decrease the risk of delirium and the severity of pain. Methods and analysis: We will include data from patients who have been enrolled into three prospective studies: ENGAGES, PODCAST, and SATISFY-SOS. All participants underwent general anesthesia for a non-neurosurgical inpatient operation, and had a postoperative hospital stay of at least one day at Barnes Jewish Hospital in St. Louis, Missouri, from February 2013 to May 2018. Â Patients included in this study have been assessed for postoperative delirium and pain severity as part of the parent studies. In the current study, determination of delirium diagnosis will be based on the Confusion Assessment Method, and the Visual Analogue Pain Scale will be used for pain severity. Data on OSA diagnosis, OSA risk and compliance with treatment will be obtained from the preoperative assessment record. Other variables that are candidate risk factors for delirium and pain will also be extracted from this record. We will use logistic regression to test whether OSA independently predicts postoperative delirium and linear regression to assess OSAs relationship to acute pain severity. We will conduct secondary analyses with subgroups to explore whether these relationships are modified by compliance with OSA treatment.</ns4:p
Star formation in W3 - AFGL333: Young stellar content, properties and roles of external feedback
One of the key questions in the field of star formation is the role of
stellar feedback on subsequent star formation process. The W3 giant molecular
cloud complex at the western border of the W4 super bubble is thought to be
influenced by the stellar winds of the massive stars in W4. AFGL333 is a ~10^4
Msun cloud within W3. This paper presents a study of the star formation
activity within AFGL333 using deep JHKs photometry obtained from the NOAO
Extremely Wide-Field Infrared Imager combined with Spitzer-IRAC-MIPS
photometry. Based on the infrared excess, we identify 812 candidate young
stellar objects in the complex, of which 99 are classified as Class I and 713
are classified as Class II sources. The stellar density analysis of young
stellar objects reveals three major stellar aggregates within AFGL333, named
here AFGL333-main, AFGL333-NW1 and AFGL333-NW2. The disk fraction within
AFGL333 is estimated to be ~50-60%. We use the extinction map made from the
H-Ks colors of the background stars to understand the cloud structure and to
estimate the cloud mass. The CO-derived extinction map corroborates the cloud
structure and mass estimates from NIR color method. From the stellar mass and
cloud mass associated with AFGL333, we infer that the region is currently
forming stars with an efficiency of ~4.5% and at a rate of ~2 - 3 Msun
Myr-1pc-2. In general, the star formation activity within AFGL333 is comparable
to that of nearby low mass star-forming regions. We do not find any strong
evidence to suggest that the stellar feedback from the massive stars of nearby
W4 super bubble has affected the global star formation properties of the
AFGL333 region.Comment: 17 pages, 9 figures, Accepted for publication in Ap
Days of our lives: Family experiences of digital technology use
© 2018 Association for Computing Machinery. This paper describes findings from a workshop, with 11 parents of children under 12 years of age, that explored family experiences of digital technology use. We found that technology experiences within everyday family life are complicated and interlinked. We highlight four experiences that featured most prominently with our participants: apprehension, ambivalence, compromise and conflict. In addition, we discuss how family values govern these experiences and how families use digital technology. This work contributes to current understandings of how family values guide technology practices. These early findings suggest that deeper understandings of family values; how they are shared, negotiated and put into action, will help inform the design of future technologies that not only support families' practices and activities, but also their experiences and aspirations
Ability of preoperative falls to predict postsurgical outcomes in non-selected patients undergoing elective surgery at an academic medical centre: Protocol for a prospective cohort study
INTRODUCTION: Falls are increasingly recognised for their ability to herald impending health decline. Despite the likely susceptibility of postsurgical patients to falls, a detailed description of postoperative falls in an unselected surgical population has never been performed. One study suggests that preoperative falls may forecast postoperative complications. However, a larger study with non-selected surgical patients and patient-centred outcomes is needed to provide the generalisability and justification necessary to implement preoperative falls assessment into routine clinical practice. The aims of this study are therefore twofold. First, we aim to describe the main features of postoperative falls in a population of unselected surgical patients. Second, we aim to test the hypothesis that a history of falls in the 6 months prior to surgery predicts postoperative falls, poor quality of life, functional dependence, complications and readmission. METHODS AND ANALYSIS: To achieve these goals, we study adult patients who underwent elective surgery at our academic medical centre and were recruited to participate in a prospective, survey-based cohort study called Systematic Assessment and Targeted Improvement of Services Following Yearlong Surgical Outcomes Surveys (SATISFY-SOS) (NCT02032030). Patients who reported falling in the 6 months prior to surgery will be considered ‘exposed.’ The primary outcome of interest is postoperative falls within 30 days of surgery. Secondary outcomes include postoperative functional dependence, quality of life (both physical and mental), in-hospital complications and readmission. Regression models will permit controlling for important confounders. ETHICS AND DISSEMINATION: The home institution's Institutional Review Board approved this study (IRB ID number 201505035). The authors will publish the findings, regardless of the results
Antibody-Based Ticagrelor Reversal Agent in Healthy Volunteers.
BACKGROUND: Ticagrelor is an oral P2Y12 inhibitor that is used with aspirin to reduce the risk of ischemic events among patients with acute coronary syndromes or previous myocardial infarction. Spontaneous major bleeding and bleeding associated with urgent invasive procedures are concerns with ticagrelor, as with other antiplatelet drugs. The antiplatelet effects of ticagrelor cannot be reversed with platelet transfusion. A rapid-acting reversal agent would be useful.
METHODS: In this randomized, double-blind, placebo-controlled, phase 1 trial, we evaluated intravenous PB2452, a monoclonal antibody fragment that binds ticagrelor with high affinity, as a ticagrelor reversal agent. We assessed platelet function in healthy volunteers before and after 48 hours of ticagrelor pretreatment and again after the administration of PB2452 or placebo. Platelet function was assessed with the use of light transmission aggregometry, a point-of-care P2Y12 platelet-reactivity test, and a vasodilator-stimulated phosphoprotein assay.
RESULTS: Of the 64 volunteers who underwent randomization, 48 were assigned to receive PB2452 and 16 to receive placebo. After 48 hours of ticagrelor pretreatment, platelet aggregation was suppressed by approximately 80%. PB2452 administered as an initial intravenous bolus followed by a prolonged infusion (8, 12, or 16 hours) was associated with a significantly greater increase in platelet function than placebo, as measured by multiple assays. Ticagrelor reversal occurred within 5 minutes after the initiation of PB2452 and was sustained for more than 20 hours (P\u3c0.001 after Bonferroni adjustment across all time points for all assays). There was no evidence of a rebound in platelet activity after drug cessation. Adverse events related to the trial drug were limited mainly to issues involving the infusion site.
CONCLUSIONS: In healthy volunteers, the administration of PB2452, a specific reversal agent for ticagrelor, provided immediate and sustained reversal of the antiplatelet effects of ticagrelor, as measured by multiple assays. (Funded by PhaseBio Pharmaceuticals; ClinicalTrials.gov number, NCT03492385.)
Adolescent menstrual health literacy in low, middle and high-income countries : a narrative review
Background: Poor menstrual health literacy impacts adolescents’ quality of life and health outcomes across the world. The aim of this systematic review was to identify concerns about menstrual health literacy in low/middle-income countries (LMICs) and high-income countries (HICs). Methods: Relevant social science and medical databases were searched for peer-reviewed papers published from January 2008 to January 2020, leading to the identification of 61 relevant studies. Results: A thematic analysis of the data revealed that LMICs report detrimental impacts on adolescents in relation to menstrual hygiene and cultural issues, while in HICs, issues related to pain management and long-term health outcomes were reported more frequently. Conclusions: In order to improve overall menstrual health literacy in LMICs and HICs, appropriate policies need to be developed, drawing on input from multiple stakeholders to ensure evidence-based and cost-effective practical interventions
Characteristics of surface-water flows in the ridge and slough landscape of Everglades National Park: implications for particulate transport
Over the last one hundred years, compartmentalization and water management activities have reduced water flow to the ridge and slough landscape of the Everglades. As a result, the once corrugated landscape has become topographically and vegetationally uniform. The focus of this study was to quantify variation in surface flow in the ridge and slough landscape and to relate flow conditions to particulate transport and deposition. Over the 2002–2003 and 2003–2004 wet seasons, surface velocities and particulate accumulation were measured in upper Shark River Slough in Everglades National Park. Landscape characteristics such as elevation, plant density and biomass also were examined to determine their impact on flow characteristics and material transport. The results of this study demonstrate that the release of water during the wet season not only increases water levels, but also increased flow speeds and particulate transport and availability. Further, flow speeds were positively and significantly correlated with water level thereby enhancing particulate transport in sloughs relative to ridges especially during peak flow periods. Our results also indicate that the distribution of biomass in the water column, including floating plants and periphyton, affects velocity magnitude and shape of vertical profiles, especially in the sloughs where Utricularia spp. and periphyton mats are more abundant. Plot clearing experiments suggest that the presence of surface periphyton and Utricularia exert greater control over flow characteristics than the identity (i.e., sawgrass or spike rush) or density of emergent macrophytes, two parameters frequently incorporated into models describing flow through vegetated canopies. Based on these results, we suggest that future modeling efforts must take the presence of floating biomass, such as Utricularia, and presence of periphyton into consideration when describing particulate transport
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