3,975 research outputs found
A Comparison of Techniques for Estimating NDVI for Agricultural Intervention Impact Assessment
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The Soultz-sous-Forêts’ Enhanced Geothermal System: A Granitic Basement Used as a Heat Exchanger to Produce Electricity
Revolution Resolution
Our submission started out as a simple class-activism project and turned into an ongoing quest for change. It is a resolution and response paper that we wrote proposing to change Fredonia\u27s legal name policy (the resolution is included in the response paper). As three transgender students, this topic is very personal and important to us. After extensive research we have found an impressive correlation between a trans-inclusive campus environment and the success rate and safety of students. Our resolution was presented to and endorsed by both the student association and university senates last semester, and we are currently serving on a task force commissioned by the president of our university and the chair of the faculty senate to change the current policy. Our end goal is to allow students to use a preferred name on their public identities (i.e. student I.D. cards, campus email, and class rosters
High Temperature Degradation Mechanisms in Polymer Matrix Composites
Polymer matrix composites are increasingly used in demanding structural applications in which they may be exposed to harsh environments. The durability of such materials is a major concern, potentially limiting both the integrity of the structures and their useful lifetimes. The goal of the current investigation is to develop a mechanism-based model of the chemical degradation which occurs, such that given the external chemical environment and temperatures throughout the laminate, laminate geometry, and ply and/or constituent material properties, we can calculate the concentration of diffusing substances and extent of chemical degradation as functions of time and position throughout the laminate. This objective is met through the development and use of analytical models, coupled to an analysis-driven experimental program which offers both quantitative and qualitative information on the degradation mechanism. Preliminary analyses using coupled diffusion/reaction model are used to gain insight into the physics of the degradation mechanisms and to identify crucial material parameters. An experimental program is defined based on the results of the preliminary analysis which allows the determination of the necessary material coefficients. Thermogravimetric analyses are carried out in nitrogen, air, and oxygen to provide quantitative information on thermal and oxidative reactions. Powdered samples are used to eliminate diffusion effects. Tests in both inert and oxidative environments allow the separation of thermal and oxidative contributions to specimen mass loss. The concentration dependency of the oxidative reactions is determined from the tests in pure oxygen. Short term isothermal tests at different temperatures are carried out on neat resin and unidirectional macroscopic specimens to identify diffusion effects. Mass loss, specimen shrinkage, the formation of degraded surface layers and surface cracking are recorded as functions of exposure time. Geometry effects in the neat resin, and anisotropic diffusion effects in the composites, are identified through the use of specimens with different aspect ratios. The data is used with the model to determine reaction coefficients and effective diffusion coefficients. The empirical and analytical correlations confirm the preliminary model results which suggest that mass loss at lower temperatures is dominated by oxidative reactions and that these reaction are limited by diffusion of oxygen from the surface. The mechanism-based model is able to successfully capture the basic physics of the degradation phenomena under a wide range of test conditions. The analysis-based test design is successful in separating out oxidative, thermal, and diffusion effects to allow the determination of material coefficients. This success confirms the basic picture of the process; however, a more complete understanding of some aspects of the physics are required before truly predictive capability can be achieved
Flood Mapping of Recent Major Hurricane Events with Synthetic Aperture Radar, Commercial Imaging, and Aerial Observations
Floodwater mapping is an important remote sensing process that is used for disaster response, recovery, and damage assessment practices. Developing a system to read in Synthetic Aperture Radar (SAR) data and perform land cover classification will allow for the production of near real-time inundation mapping, enabling government and emergency response entities to get a preliminary idea of the situation. SAR is a unique remote sensing tool. Data in this project was obtained by NASA Jet Propulsion Laboratorys Uninhabited Aerial Vehicle SAR (UAVSAR), an L-band radar mounted to a Gulfstream III jet. Data collected by UAVSAR is similar to what will be available from the NASA-Indian Space Research Organization (NISAR) mission starting in early 2022. Using Python and ArcGIS applications, a model was developed using training samples taken from NOAA post-event aerial photography and UAVSAR data gathered in the aftermath of Hurricane Florence in September 2018
Mobilités étudiantes Sud-Nord : trajectoires scolaires de Marocains en France et insertion professionnelle au Maroc
Authenticity in Discursive Practices of the Online Market for Second-Hand Luxury Clothing
Authenticity is a particularly sensitive and salient issue in the online market for second-hand luxury clothing, and it is still little explored in the field of consumption studies. In this study we sought to analyze how authenticity is represented in discursive practices of the Brazilian online market for second-hand luxury clothing. The corpus of the work consisted of data collected through interviews in five stores of the Brazilian online market of luxury second-hand clothing. The data were analyzed using the Critical Discourse Analysis (CDA), proposed by Fairclough (1992), articulated to the sociocultural perspective of consumption. From the discursive categories Subject, Interdiscursivity, Intertextuality, Transitivity System, and Appraisal System, we perceived that the process of legitimizing the stores and the representations of authenticity are overlapped and traversed significantly by historical, social, and cultural aspects. We conclude that insofar as it becomes difficult to ensure objective authenticity, an interpretative dimension emerges, elaborated from the influence of sociocultural factors that underlie the judgment on what is authentic luxury, which in the scenario investigated are indexes of expression of high luxury. In this case, the origins and trajectories that are recognized as references of elite distinction for Brazilian consumers are important elements for the interpretation of authenticity
Thioester reduction and aldehyde transamination are universal steps in actinobacterial polyketide alkaloid biosynthesis
Actinobacteria produce a variety of polyketide alkaloids with unusual structures. Recently, it was shown that a type I modular polyketide synthase (PKS) is involved in the assembly of coelimycin P1, a polyketide alkaloid produced by Streptomyces coelicolor M145. However, the mechanisms for converting the product of the PKS to coelimycin P1 remain to be elucidated. Here we show that the C-terminal thioester reductase (TR) domain of the PKS and an ω-transaminase are responsible for release of the polyketide chain as an aldehyde and its subsequent reductive amination. Bioinformatics analyses identified numerous gene clusters in actinobacterial genomes that encode modular PKSs with a C-terminal TR domain and a homolog of the ω-transaminase. These are predicted to direct the biosynthesis of both known and novel polyketide alkaloids, suggesting that reductive chain release and transamination constitutes a conserved mechanism for the biosynthesis of such metabolites
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From therapeutic landscapes to healthy spaces, places and practices: a scoping review
The term 'therapeutic landscapes' was first coined by health geographer, Wilbert Gesler, in 1992 to explore why certain environments seem to contribute to a healing sense of place. Since then, the concept and its applications have evolved and expanded as researchers have examined the dynamic material, affective and socio-cultural roots and routes to experiences of health and wellbeing in specific places. Drawing on a scoping review of studies of these wider therapeutic landscapes published between 2007 and 2016, this paper explores how, where, and to what benefit the 'therapeutic landscapes' concept has been applied to date, and how such applications have contributed to its critical evolution as a relevant and useful concept in health geography. Building on themes included in two earlier (1999, 2007) edited volumes on Therapeutic Landscapes, we summarise the key themes identified in the review, broadly in keeping with the core material, social, spiritual and symbolic dimensions of the concept initially posited by Gesler. Through this process, we identify strengths and limitations of the concept and its applications, as well as knowledge gaps and promising future directions for work in this field, reflecting critically on its value within health geography and its potential contribution to wider interdisciplinary discussions and debates around 'healthy' spaces, places, and related practices. [Abstract copyright: Copyright © 2017 Elsevier Ltd. All rights reserved.
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