4,196 research outputs found

    Effects of aircraft noise on flight and ground structures

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    Acoustic loads measured on jet-powered STOL configurations are presented for externally blown and upper surface blown flap models ranging in size from a small laboratory model up to a full-scale aircraft model. The implications of the measured loads for potential acoustic fatigue and cabin noise are discussed. Noise transmission characteristics of light aircraft structures are presented. The relative importance of noise transmission paths, such as fuselage sidewall and primary structure, is estimated. Acceleration responses of a historic building and a residential home are presented for flyover noise from subsonic and supersonic aircraft. Possible effects on occupant comfort are assessed. The results from these three examples show that aircraft noise can induce structural responses that are large enough to require consideration in the design or operation of the aircraft

    Cleavage of DFNA5 by caspase-3 during apoptosis mediates progression to secondary necrotic/pyroptotic cell death.

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    Apoptosis is a genetically regulated cell suicide programme mediated by activation of the effector caspases 3, 6 and 7. If apoptotic cells are not scavenged, they progress to a lytic and inflammatory phase called secondary necrosis. The mechanism by which this occurs is unknown. Here we show that caspase-3 cleaves the GSDMD-related protein DFNA5 after Asp270 to generate a necrotic DFNA5-N fragment that targets the plasma membrane to induce secondary necrosis/pyroptosis. Cells that express DFNA5 progress to secondary necrosis, when stimulated with apoptotic triggers such as etoposide or vesicular stomatitis virus infection, but disassemble into small apoptotic bodies when DFNA5 is deleted. Our findings identify DFNA5 as a central molecule that regulates apoptotic cell disassembly and progression to secondary necrosis, and provide a molecular mechanism for secondary necrosis. Because DFNA5-induced secondary necrosis and GSDMD-induced pyroptosis are dependent on caspase activation, we propose that they are forms of programmed necrosis

    Teaching Disruptive Students: An Indictment of Colorblind Teacher Education Programs

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    Teacher education programs do not sufficiently prepare White teachers to work with Black and Latino students in disciplinary alternative schools. From a critical race theory in education perspective, prepared White teachers are aware of their own ethnocentrism and, subsequently, develop anti-racist pedagogy and curricula

    Recent Advances to Estimation of Fixed-Interface Modal Models Using Dynamic Substructuring

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    In 2010, Allen & Mayes proposed to estimate the fixed-interface modes of a structure by measuring the modes of the structure bolted to a fixture and then applying constraints to the fixture using the transmission simulator method. While the method proved useful, and has indeed been used in studies since that point, a few peculiarities were noted. First, in some cases the estimated fixed-base natural frequencies were observed to converge very slowly to the true values (in simulated experiments) as the number of constraints was increased. To formulate these constraints, prior studies used only the free-interface modes of the fixture or the measured modes of the assembly. This work extends that to consider other sets of constraints, showing improved results. Furthermore, in some prior studies it has been observed that there were errors of more than 10% in the natural frequencies even when the fixture motion was hundreds of times smaller than the motion of the structure of interest (and so it had presumably been removed). This work explores this phenomenon, seeking to use the strain energy in the fixture, to the extent that it can be estimated using a test-analysis model for the fixture, as a metric to predict frequency error. The proposed methods are explored by applying them to simulated measurements from a beam and from the NASA Space Launch System coupled to the Mobile Launcher

    Pengaruh Suku Bunga Dan Produk Domestik Regional Bruto (PDRB) Terhadap Investasi Sektor Properti Di Kota Pekanbaru Periode 2002-2013

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    This study aims to determine the analysis of the Interest Rate and The Gross Domestic Regional Product (GDRP) Variable to Investment Property Sector in Pekanbaru. The data used in this study was a time series data from 2002 to 2013 were sourced from Bank Indonesia and Agency of city planning (Badan Perencanaan Kota). This study used quantitative research methods, and analyzed by using multiple linear regression analysis by using SPSS 21 software programfor Windows computers. In this study, the independent variable was Interest Rate (X1) and Gross Domestic Regional Product (GDRP) (X2) while the dependent variable was Investment Property Sector in Pekanbaru (Y). This study tested thehypothesis of regression coefficient (coefficient of determination, a significant test concurrent / F test, and the significant individual test / t test). The result showed the variable Interest Rate and Gross Domestic Regional Product (GDRP) at once / simultaneously had a significant influence on the Investment Property Sector in Pekanbaru. The individual test / partial showed that Gross Domestic Regional Product (GDRP) variable acquired that contributes greater than the variable Interest Rate to the Investment Property Sector in Pekanbar

    Self-Critical Perfectionism Predicts Lower Cortisol Response to Experimental Stress in Patients With Chronic Fatigue Syndrome

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    Previous studies have shown that self-critical perfectionism (SCP) is implicated in Chronic Fatigue Syndrome (CFS). However, to date, no studies exist that have examined whether SCP is related to a hypofunction of the hypothalamic-pituitary-adrenal (HPA) axis, which has been shown to be a key factor in the pathophysiology of CFS. We conducted a quasi-experimental study to examine the effects of SCP (as measured with the Depressive Experiences Questionnaire) on stress reactivity in a sample of 41 female CFS patients. Participants were exposed to the Trier Social Stress Test (TSST). Both subjective stress and salivary cortisol levels were measured until 90 minutes after the TSST. We also examined the relationship between stress reactivity and illness characteristics (i.e. duration and severity of symptoms). The results showed that SCP was associated with increased subjective stress reactivity, but with decreased HPA-axis reactivity as indicated by a blunted cortisol response to the TSST. Reduced cortisol reactivity was associated with greater symptom severity. There was no relationship between cortisol reactivity and illness duration. Our findings suggest that SCP is associated with loss of resilience of the neurobiological stress response system in CFS

    Are infestations of Cymomelanodactylus killing Acropora cytherea in the Chagos archipelago?

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    Associations between branching corals and infaunal crabs are well known, mostly due to the beneficial effects of Trapezia and Tetralia crabs in protecting host corals from crown-of-thorns starfish (e.g., Pratchett et al. 2000) and/or sedimentation (Stewart et al. 2006). These crabs are obligate associates of live corals and highly prevalent across suitable coral hosts, with 1–2 individuals per colony (Patton 1994). Cymo melanodactylus (Fig. 1) are also prevalent in branching corals, mostly Acropora, and are known to feed on live coral tissue, but are generally found in low abundance (<3 per colony) and do not significantly affect their host corals (e.g., Patton 1994). In the Chagos archipelago, however, infestations of Cymo melanodactylus were found on recently dead and dying colonies of Acropora cytherea
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