291 research outputs found
Matkailun kokonaisjärjestelmä ja matkailututkimus Suomessa
The Whole Tourism System and tourism research in Finland
Neil Leiper developed throughout the end of the last millennium an overarching theory â The Whole Tourism System (WTS) â to describe the complexity of tourism for decision makers to use, and for academics to contemplate and apply. Leiperâs intention was to show how tourism can be understood as an interconnected system, rather than non-related components that are managed separately. WTS is still today one of the best recognised systemic attempts to describe the components included in tourism, without being overly complex. The Finnish Journal of Tourism Research (FJTR) publishes academic articles in Finnish, Swedish, and English offering an opportunity to reach a Finnish tourism research audience in their mother tongue. This theoretical article aims at supporting future tourism research by presenting the WTS to a wider Finnish audience, and conducting a content analysis of the 13 FJTR editions published so far. The article organises the FJTR content according to the components of WTS to see how well the theory incorporates the âwholeâ of tourism and which components Finnish tourism research so far has emphasised. Furthermore, the article points out potential gaps in the research. Findings portray a major focus of research aimed at destinations and tourists, and to some extent on tourism industries, thus almost totally neglecting research about generating regions and transit routes.Neil Leiper developed throughout the end of the last millennium an overarching theory â The Whole Tourism System (WTS) â to describe the complexity of tourism for decision makers to use, and for academics to contemplate and apply. Leiperâs intention was to show how tourism can be understood as an interconnected system, rather than non-related components that are managed separately. WTS is still today one of the best recognised systemic attempts to describe the components included in tourism, without being overly complex. The Finnish Journal of Tourism Research (FJTR) publishes academic articles in Finnish, Swedish, and English offering an opportunity to reach a Finnish tourism research audience in their mother tongue. This theoretical article aims at supporting future tourism research by presenting the WTS to a wider Finnish audience, and conducting a content analysis of the 13 FJTR editions published so far. The article organises the FJTR content according to the components of WTS to see how well the theory incorporates the âwholeâ of tourism and which components Finnish tourism research so far has emphasised. Furthermore, the article points out potential gaps in the research. Findings portray a major focus of research aimed at destinations and tourists, and to some extent on tourism industries, thus almost totally neglecting research about generating regions and transit routes
Technical Specification for the CLIC Two-Beam Module
A high-energy (0.5-3 TeV centre-of-mass), highluminosity Compact Linear Collider (CLIC) is being studied at CERN [1]. The CLIC main linacs, 21-km long each, are composed of 2-m long two beam modules. This paper presents their current layout, the main requirements for the different sub-systems (alignment, supporting, stabilization, cooling and vacuum) as well as the status of their integration
Selective cleavage of lignin β-O-4 aryl ether bond by β-etherase of the white-rot fungus Dichomitus squalens.
Production of value-added compounds from a renewable aromatic polymer, lignin, has proven to be challenging. Chemical procedures, involving harsh reaction conditions, are costly and often result in nonselective degradation of lignin linkages. Therefore, enzymatic catalysis with selective cleavage of lignin bonds provides a sustainable option for lignin valorization. In this study, we describe the first functionally characterized fungal intracellular beta-etherase from the wood-degrading white-rot basidiomycete Dichomitus squalens. This enzyme, Ds-GST1, from the glutathione-Stransferase superfamily selectively cleaved the beta-O-4 aryl ether bond of a dimeric lignin model compound in a glutathionedependent reaction. Ds-GST1 also demonstrated activity on polymeric synthetic lignin fractions, shown by a decrease in molecular weight distribution of the lactase -oxidized guaiacyl dehydrogenation polymer. In addition to a possible role of DsGST1 in intracellular catabolism of lignin-derived aromatic compounds, the cleavage of the most abundant linkages in lignin under mild reaction conditions makes this biocatalyst an attractive green alternative in biotechnological applications.Peer reviewe
Depolymerization of biorefinery lignin by improved laccases of the white-rot fungus Obba rivulosa
Fungal laccases are attracting enzymes for sustainable valorization of biorefinery lignins. To improve the lignin oxidation capacity of two previously characterized laccase isoenzymes from the white-rot fungus Obba rivulosa, we mutated their substrate-binding site at T1. As a result, the pH optimum of the recombinantly produced laccase variant rOrLcc2-D206N shifted by three units towards neutral pH. O. rivulosa laccase variants with redox mediators oxidized both the dimeric lignin model compound and biorefinery poplar lignin. Significant structural changes, such as selective benzylic alpha-oxidation, were detected by nuclear magnetic resonance analysis, although no polymerization of lignin was observed by gel permeation chromatography. This suggests that especially rOrLcc2-D206N is a promising candidate for lignin-related applications.Peer reviewe
Fungal Treatment Modifies Kraft Lignin for Lignin- and Cellulose-Based Carbon Fiber Precursors
The kraft lignin's low molecular weight and too high hydroxyl content hinder its application in bio-based carbon fibers. In this study, we were able to polymerize kraft lignin and reduce the amount of hydroxyl groups by incubating it with the white-rot fungus Obba rivulosa. Enzymatic radical oxidation reactions were hypothesized to induce condensation of lignin, which increased the amount of aromatic rings connected by carbon-carbon bonds. This modification is assumed to be beneficial when aiming for graphite materials such as carbon fibers. Furthermore, the ratio of remaining aliphatic hydroxyls to phenolic hydroxyls was increased, making the structure more favorable for carbon fiber production. When the modified lignin was mixed together with cellulose, the mixture could be spun into intact precursor fibers by using dry-jet wet spinning. The modified lignin leaked less to the spin bath compared with the unmodified lignin starting material, making the recycling of spin-bath solvents easier. The stronger incorporation of modified lignin in the precursor fibers was confirmed by composition analysis, thermogravimetry, and mechanical testing. This work shows how white-rot fungal treatment can be used to modify the structure of lignin to be more favorable for the production of bio-based fiber materials.Peer reviewe
Toward on-sky adaptive optics control using reinforcement learning Model-based policy optimization for adaptive optics
Context. The direct imaging of potentially habitable exoplanets is one prime science case for the next generation of high contrast imaging instruments on ground-based, extremely large telescopes. To reach this demanding science goal, the instruments are equipped with eXtreme Adaptive Optics (XAO) systems which will control thousands of actuators at a framerate of kilohertz to several kilohertz. Most of the habitable exoplanets are located at small angular separations from their host stars, where the current control laws of XAO systems leave strong residuals. Aims. Current AO control strategies such as static matrix-based wavefront reconstruction and integrator control suffer from a temporal delay error and are sensitive to mis-registration, that is, to dynamic variations of the control system geometry. We aim to produce control methods that cope with these limitations, provide a significantly improved AO correction, and, therefore, reduce the residual flux in the coronagraphic point spread function (PSF). Methods. We extend previous work in reinforcement learning for AO. The improved method, called the Policy Optimization for Adaptive Optics (PO4AO), learns a dynamics model and optimizes a control neural network, called a policy. We introduce the method and study it through numerical simulations of XAO with Pyramid wavefront sensor (PWFS) for the 8-m and 40-m telescope aperture cases. We further implemented PO4AO and carried out experiments in a laboratory environment using Magellan Adaptive Optics eXtreme system (MagAO-X) at the Steward laboratory. Results. PO4AO provides the desired performance by improving the coronagraphic contrast in numerical simulations by factors of 3-5 within the control region of deformable mirror and PWFS, both in simulation and in the laboratory. The presented method is also quick to train, that is, on timescales of typically 5-10 s, and the inference time is sufficiently small (Peer reviewe
Toward on-sky adaptive optics control using reinforcement learning Model-based policy optimization for adaptive optics
Context. The direct imaging of potentially habitable exoplanets is one prime science case for the next generation of high contrast imaging instruments on ground-based, extremely large telescopes. To reach this demanding science goal, the instruments are equipped with eXtreme Adaptive Optics (XAO) systems which will control thousands of actuators at a framerate of kilohertz to several kilohertz. Most of the habitable exoplanets are located at small angular separations from their host stars, where the current control laws of XAO systems leave strong residuals. Aims. Current AO control strategies such as static matrix-based wavefront reconstruction and integrator control suffer from a temporal delay error and are sensitive to mis-registration, that is, to dynamic variations of the control system geometry. We aim to produce control methods that cope with these limitations, provide a significantly improved AO correction, and, therefore, reduce the residual flux in the coronagraphic point spread function (PSF). Methods. We extend previous work in reinforcement learning for AO. The improved method, called the Policy Optimization for Adaptive Optics (PO4AO), learns a dynamics model and optimizes a control neural network, called a policy. We introduce the method and study it through numerical simulations of XAO with Pyramid wavefront sensor (PWFS) for the 8-m and 40-m telescope aperture cases. We further implemented PO4AO and carried out experiments in a laboratory environment using Magellan Adaptive Optics eXtreme system (MagAO-X) at the Steward laboratory. Results. PO4AO provides the desired performance by improving the coronagraphic contrast in numerical simulations by factors of 3-5 within the control region of deformable mirror and PWFS, both in simulation and in the laboratory. The presented method is also quick to train, that is, on timescales of typically 5-10 s, and the inference time is sufficiently small (Peer reviewe
Exact and near backscattering measurements of the linear depolarisation ratio of various ice crystal habits generated in a laboratory cloud chamber
Š 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license(http://creativecommons.org/licenses/by/4.0/).Ice clouds were generated in the Manchester Ice Cloud Chamber (MICC), and the backscattering linear depolarisation ratio, δ, was measured for a variety of habits. To create an assortment of particle morphologies, the humidity in the chamber was varied throughout each experiment, resulting in a range of habits from the pristine to the complex. This technique was repeated at three temperatures: â7 °C, â15 °C and â30 °C, in order to produce both solid and hollow columns, plates, sectored plates and dendrites. A linearly polarised 532 nm continuous wave diode laser was directed through a section of the cloud using a non-polarising 50:50 beam splitter. Measurements of the scattered light were taken at 178°, 179° and 180°, using a GlanâTaylor prism to separate the co- and cross-polarised components. The intensities of these components were measured using two amplified photodetectors and the ratio of the cross- to co-polarised intensities was measured to find the linear depolarisation ratio. In general, it was found that Ray Tracing over-predicts the linear depolarisation ratio. However, by creating more accurate particle models which better represent the internal structure of ice particles, discrepancies between measured and modelled results (based on Ray Tracing) were reduced.Peer reviewe
Quantitative proteomic characterization and comparison of T helper 17 and induced regulatory T cells
T helper 17 (Th17) cells and induced regulatory T (iTreg) cells are two
subsets of T helper cells differentiated from naĂŻve cells that play
important roles in autoimmune diseases, immune homeostasis, and tumor
immunity. The differentiation process is achieved by changes in numerous
proteins, including transcription regulators, enzymes, membrane
receptors, and cytokines, which are critical in lineage commitment. To
profile protein expression changes in Th17 and iTreg cells, we polarized
murine naĂŻve CD4+ T (Thp) cells in vitro to Th17 and iTreg cells and
performed quantitative proteomic analysis of these cells. More than
4,000 proteins, covering almost all subcellular compartments, were
detected. Quantitative comparison of the protein expression profiles
resulted in the identification of proteins specifically expressed in the
Th17 and iTreg cells. Importantly, our combined analysis of proteome
and gene expression data revealed protein expression changes that were
not associated with changes at the transcriptional level. The present
study serves as a valuable resource that may prove useful in developing
treatment of autoimmune diseases and cancer.</p
Instructional multimedia: An investigation of student and instructor attitudes and student study behavior
<p>Abstract</p> <p>Background</p> <p>Educators in allied health and medical education programs utilize instructional multimedia to facilitate psychomotor skill acquisition in students. This study examines the effects of instructional multimedia on student and instructor attitudes and student study behavior.</p> <p>Methods</p> <p>Subjects consisted of 45 student physical therapists from two universities. Two skill sets were taught during the course of the study. Skill set one consisted of knee examination techniques and skill set two consisted of ankle/foot examination techniques. For each skill set, subjects were randomly assigned to either a control group or an experimental group. The control group was taught with live demonstration of the examination skills, while the experimental group was taught using multimedia. A cross-over design was utilized so that subjects in the control group for skill set one served as the experimental group for skill set two, and vice versa. During the last week of the study, students and instructors completed written questionnaires to assess attitude toward teaching methods, and students answered questions regarding study behavior.</p> <p>Results</p> <p>There were no differences between the two instructional groups in attitudes, but students in the experimental group for skill set two reported greater study time alone compared to other groups.</p> <p>Conclusions</p> <p>Multimedia provides an efficient method to teach psychomotor skills to students entering the health professions. Both students and instructors identified advantages and disadvantages for both instructional techniques. Reponses relative to instructional multimedia emphasized efficiency, processing level, autonomy, and detail of instruction compared to live presentation. Students and instructors identified conflicting views of instructional detail and control of the content.</p
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