559 research outputs found
Glimmers: Resolving the Privacy/Trust Quagmire
Many successful services rely on trustworthy contributions from users. To
establish that trust, such services often require access to privacy-sensitive
information from users, thus creating a conflict between privacy and trust.
Although it is likely impractical to expect both absolute privacy and
trustworthiness at the same time, we argue that the current state of things,
where individual privacy is usually sacrificed at the altar of trustworthy
services, can be improved with a pragmatic , which allows
services to validate user contributions in a trustworthy way without forfeiting
user privacy. We describe how trustworthy hardware such as Intel's SGX can be
used client-side -- in contrast to much recent work exploring SGX in cloud
services -- to realize the Glimmer architecture, and demonstrate how this
realization is able to resolve the tension between privacy and trust in a
variety of cases
Explaining Earths Energy Budget: CERES-Based NASA Resources for K-12 Education and Public Outreach
Among atmospheric scientists, the importance of the Earth radiation budget concept is well understood. Papers have addressed the topic for over 100 years, and the large Clouds and the Earth's Radiant Energy System (CERES) science team (among others), with its multiple on-orbit instruments, is working hard to quantify the details of its various parts. In education, Earth's energy budget is a concept that generally appears in middle school and Earth science curricula, but its treatment in textbooks leaves much to be desired. Students and the public hold many misconceptions, and very few people have an appreciation for the importance of this energy balance to the conditions on Earth. More importantly, few have a correct mental model that allows them to make predictions and understand the effect of changes such as increasing greenhouse gas concentrations. As an outreach element of the core CERES team at NASA Langley, a multi-disciplinary group of scientists, educators, graphic artists, writers, and web developers has been developing and refining graphics and resources to explain the Earth's Energy budget over the last few decades. Resources have developed through an iterative process involving ongoing use in front of a variety of audiences, including students and teachers from 3rd to 12th grade as well as public audiences
School Safety in Rural Communities: A Qualitative Phenomenological Research Study
Many students in rural schools have negative school safety perceptions. The purpose of this qualitative phenomenological research study was to investigate the school safety perceptions of students in rural elementary, middle, and high schools in a public school district in South Carolina. The school safety perceptions of students in grades three through twelve were investigated and examined.
The setting for this study took place in a rural school district in the Pee Dee region of South Carolina. Three schools in this district were utilized. Forty-three students participated in a short school safety interest survey. The survey provided basic information such as age, race, gender, grade, household, how long they have been in Daisy County, how safe they feel at school, whether they would be willing to participate in an interview about school safety at their school and ask for an email address for communication. Only students who presented a signed parent consent form were provided with an email with the survey. Parents could consent for their child to participate in the survey and interview or the survey only. They were also provided with the opportunity to be present during the interview. The survey was anonymous. A sample of nine students were invited from the school safety interest survey to be interviewed. The interviews consisted of nine structured questions in a specific order for consistency. Interview questions from the perspective of qualitative research provide an open-ended, thorough investigation of experiences from the point of view of the interviewee (Roberts, 2020). The participants presented their perceptions of school safety by answering the questions using their prior knowledge and points of view.
The nine participants concluded that the adults in the school help create a safe school climate, the outside environment could make them feel unsafe, and there is a need for more security in their schools. This study was designed to investigate the school safety perceptions of students in rural elementary, middle, and high schools. This research has the potential to impact schools in rural communities by investigating the perceptions of students. Students are the individuals who are most impacted by school safety. This research will also present information concerning what has occurred and what could possibly occur from the points of view of the students. This information will provide support and aid to schools in rural communities. This study has the potential to add to school safety research literature and identify best practices for school safety in rural communities
Central but not systemic administration of XPro1595 is therapeutic following moderate spinal cord injury in mice
BACKGROUND: Glial cell activation and overproduction of inflammatory mediators in the central nervous system (CNS) have been implicated in acute traumatic injuries to the CNS, including spinal cord injury (SCI). Elevated levels of the proinflammatory cytokine tumor necrosis factor (TNF), which exists in both a soluble (sol) and a transmembrane (tm) form, have been found in the lesioned cord early after injury. The contribution of solTNF versus tmTNF to the development of the lesion is, however, still unclear. METHODS: We tested the effect of systemically or centrally blocking solTNF alone, using XPro1595, versus using the drug etanercept to block both solTNF and tmTNF compared to a placebo vehicle following moderate SCI in mice. Functional outcomes were evaluated using the Basso Mouse Scale, rung walk test, and thermal hyperalgesia analysis. The inflammatory response in the lesioned cord was investigated using immunohistochemistry and western blotting analyses. RESULTS: We found that peripheral administration of anti-TNF therapies had no discernable effect on locomotor performances after SCI. In contrast, central administration of XPro1595 resulted in improved locomotor function, decreased anxiety-related behavior, and reduced damage to the lesioned spinal cord, whereas central administration of etanercept had no therapeutic effects. Improvements in XPro1595-treated mice were accompanied by increases in Toll-like receptor 4 and TNF receptor 2 (TNFR2) protein levels and changes in Iba1 protein expression in microglia/macrophages 7 and 28 days after SCI. CONCLUSIONS: These studies suggest that, by selectively blocking solTNF, XPro1595 is neuroprotective when applied directly to the lesioned cord. This protection may be mediated via alteration of the inflammatory environment without suppression of the neuroprotective effects of tmTNF signaling through TNFR2
Three-Dimensional Camera Calibration Technique for Stereo Imaging Velocimetry Experiments
A three-dimensional camera calibration technique is developed by combining two, 2-D camera calibrations for an orthogonal stereo viewing geometry. The left camera view (YZ view) and the right camera view (XZ view) are calibrated separately and then combined to produce an XYZ (3-D) calibration routine, Our technique employs three parallel calibration planes. One is placed along the main diagonal of the cubic experimental chamber, and the other two planes are placed known distances in front of it and behind it within the chamber. Both cameras view the calibration points on the planes simultaneously. Given the coordinates of a number of points, we use a physical model to determine the exact pixel locations of the calibration points. After inverting the model equations, we input the absolute coordinates and measured pixel locations into a least-squares fitting algorithm to obtain the experimental camera parameters for each camera individually, We then combine the two camera views via a ray-tracing method. We calibrated 3-in.(3) (7.62-mm(3)), 4-in.(3) (10.16-mm(3)), 5-in.(3) (12.70-mm(3)), and 6-in.(3) (15.24-mm(3)) chambers with accuracies between 1.66 and 2.01 pixels (0.60 and 0.77% of full field), 1.26 and 1.86 pixels (0.43 and 0.63% of full field), 1.16 and 1.34 pixels (0.33 and 0.39% of full field), and 1.91 and 2.49 pixels (0.59 and 0.77% of full field), respectively, using our 3-D camera calibration routine. (C) 1997 Society of Photo-Optical Instrumentation Engineers
Three-Dimensional Camera Calibration Technique for Stereo Imaging Velocimetry Experiments
A three-dimensional camera calibration technique is developed by combining two, 2-D camera calibrations for an orthogonal stereo viewing geometry. The left camera view (YZ view) and the right camera view (XZ view) are calibrated separately and then combined to produce an XYZ (3-D) calibration routine, Our technique employs three parallel calibration planes. One is placed along the main diagonal of the cubic experimental chamber, and the other two planes are placed known distances in front of it and behind it within the chamber. Both cameras view the calibration points on the planes simultaneously. Given the coordinates of a number of points, we use a physical model to determine the exact pixel locations of the calibration points. After inverting the model equations, we input the absolute coordinates and measured pixel locations into a least-squares fitting algorithm to obtain the experimental camera parameters for each camera individually, We then combine the two camera views via a ray-tracing method. We calibrated 3-in.(3) (7.62-mm(3)), 4-in.(3) (10.16-mm(3)), 5-in.(3) (12.70-mm(3)), and 6-in.(3) (15.24-mm(3)) chambers with accuracies between 1.66 and 2.01 pixels (0.60 and 0.77% of full field), 1.26 and 1.86 pixels (0.43 and 0.63% of full field), 1.16 and 1.34 pixels (0.33 and 0.39% of full field), and 1.91 and 2.49 pixels (0.59 and 0.77% of full field), respectively, using our 3-D camera calibration routine. (C) 1997 Society of Photo-Optical Instrumentation Engineers
Stereo imaging velocimetry for microgravity applications
Stereo imaging velocimetry is the quantitative measurement of three-dimensional flow fields using two sensors recording data from different vantage points. The system described in this paper, under development at NASA Lewis Research Center in Cleveland, Ohio, uses two CCD cameras placed perpendicular to one another, laser disk recorders, an image processing substation, and a 586-based computer to record data at standard NTSC video rates (30 Hertz) and reduce it offline. The flow itself is marked with seed particles, hence the fluid must be transparent. The velocimeter tracks the motion of the particles, and from these we deduce a multipoint (500 or more), quantitative map of the flow. Conceptually, the software portion of the velocimeter can be divided into distinct modules. These modules are: camera calibration, particle finding (image segmentation) and centroid location, particle overlap decomposition, particle tracking, and stereo matching. We discuss our approach to each module, and give our currently achieved speed and accuracy for each where available
Neuropathic pain-induced depressive-like behavior and hippocampal neurogenesis and plasticity are dependent on TNFR1 signaling
Patients suffering from neuropathic pain have a higher incidence of mood disorders such as depression. Increased expression of tumor necrosis factor (TNF) has been reported in neuropathic pain and depressive-like conditions and most of the pro-inflammatory effects of TNF are mediated by the TNF receptor 1 (TNFR1). Here we sought to investigate: (1) the occurrence of depressive-like behavior in chronic neuropathic pain and the associated forms of hippocampal plasticity, and (2) the involvement of TNFR1-mediated TNF signaling as a possible regulator of such events. Neuropathic pain was induced by chronic constriction injury of the sciatic nerve in wild-type and TNFR1(-/-) mice. Anhedonia, weight loss and physical state were measured as symptoms of depression. Hippocampal neurogenesis, neuroplasticity, myelin remodeling and TNF/TNFRs expression were analyzed by immunohistochemical analysis and western blot assay. We found that neuropathic pain resulted in the development of depressive symptoms in a time dependent manner and was associated with profound hippocampal alterations such as impaired neurogenesis, reduced expression of neuroplasticity markers and myelin proteins. The onset of depressive-like behavior also coincided with increased hippocampal levels of TNF, and decreased expression of TNF receptor 2 (TNFR2), which were all fully restored after mice spontaneously recovered from pain. Notably, TNFR1(-/-) mice did not develop depressive-like symptoms after injury, nor were there changes in hippocampal neurogenesis and plasticity. Our data show that neuropathic pain induces a cluster of depressive-like symptoms and profound hippocampal plasticity that are dependent on TNF signaling through TNFR1
Candida glabrata : a review of its features and resistance
Candida species belong to the normal microbiota of the oral cavity and gastrointestinal and vaginal tracts, and are responsible for several clinical manifestations, from mucocutaneous overgrowth to bloodstream infections. Once believed to be non-pathogenic, Candida glabrata was rapidly blamable for many human diseases. Year after year, these pathological circumstances are more recurrent and problematic to treat, especially when patients reveal any level of immunosuppression. These difficulties arise from the capacity of C. glabrata to form biofilms and also from its high resistance to traditional antifungal therapies. Thus, this review intends to present an excerpt of the biology, epidemiology, and pathology of C. glabrata, and detail an approach to its resistance mechanisms based on studies carried out up to the present.The authors are grateful to strategic project PTDC/SAU-MIC/119069/2010 for the financial support to the research center and for Celia F. Rodrigues' grant
Redirecting the substrate specificity of heparan sulfate 2-O-sulfotransferase by structurally guided mutagenesis
Heparan sulfate (HS) is a polysaccharide involved in essential physiological functions from regulating cell growth to blood coagulation. HS biosynthesis involves multiple specialized sulfotransferases such as 2-O-sulfotransferase (2OST) that transfers the sulfo group to the 2-OH position of iduronic acid (IdoA) or glucuronic acid (GlcA) within HS. Here, we report the homotrimeric crystal structure of 2OST from chicken, in complex with 3′-phosphoadenosine 5′-phosphate. Structural based mutational analysis has identified amino acid residues that are responsible for substrate specificity. The mutant R189A only transferred sulfates to GlcA moieties within the polysaccharide whereas mutants Y94A and H106A preferentially transferred sulfates to IdoA units. Our results demonstrate the feasibility for manipulating the substrate specificity of 2OST to synthesize HS with unique sulfation patterns. This work will aid the development of an enzymatic approach to synthesize heparin-based therapeutics
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