Sample records for random vitrinite reflectance

  1. Standardization of vitrinite reflectance measurements in shale petroleum systems: How accurate are my Ro data? (United States)

    Hackley, Paul C.


    Vitrinite reflectance generally is considered the most robust thermal maturity parameter available for application to hydrocarbon exploration and petroleum system evaluation. However, until 2011 there was no standardized methodology available to provide guidelines for vitrinite reflectance measurements in shale. Efforts to correct this deficiency resulted in publication of ASTM D7708-11: Standard test method for microscopical determination of the reflectance of vitrinite dispersed in sedimentary rocks. In 2012-2013, an interlaboratory exercise was conducted to establish precision limits for the measurement technique. Six samples, representing a wide variety of shale, were tested in duplicate by 28 analysts in 22 laboratories from 14 countries. Samples ranged from immature to overmature (Ro 0.31-1.53%), from organic-rich to organic-lean (1-22 wt.% total organic carbon), and contained Type I (lacustrine), Type II (marine), and Type III (terrestrial) kerogens. Repeatability values (difference between repetitive results from same operator, same conditions) ranged from 0.03-0.11% absolute reflectance, whereas reproducibility values (difference between results obtained on same test material by different operators, different laboratories) ranged from 0.12-0.54% absolute reflectance. Repeatability and reproducibility degraded consistently with increasing maturity and decreasing organic content. However, samples with terrestrial kerogens (Type III) fell off this trend, showing improved levels of reproducibility due to higher vitrinite content and improved ease of identification. Operators did not consistently meet the reporting requirements of the test method, indicating that a common reporting template is required to improve data quality. The most difficult problem encountered was the petrographic distinction of solid bitumens and low-reflecting inert macerals from vitrinite when vitrinite occurred with reflectance ranges overlapping the other components. Discussion among

  2. Implications from vitrinite reflectance in the fore arc sequence of Coastal Range, Eastern Taiwan (United States)

    Chim, L. K.; Tsai, L. Y.; Yen, J. Y.; Chang, C. P.; Liou, Y. S.; Horng-Yen, Y.


    The Luzon arc and Eurasian arc-continental collision caused Taiwan orogeny propagating from north to south. Illite crystallinity in Madagida sections, southern coastal range showed the old age samples gradually increased upward had been reported in previous studies. These results indicated the origin of metamorphic signal can be preserve. In this study, five cross-river sections were chosen from north to south of coastal range: Shuilien north, Tingzhulou, Loho, Sanshien, and Madagida. Then, macerals from mudstones and/or coalified woods were extracted and made into pallets for vitrinite reflectance measurement. Sanshien, Loho and Madagida section mudstone extracted samples show that vitrinite reflectance increased gradationally from the older Fanshuliao Formation to the younger Paliwan Formation. On the other hand, Shuilien north and Tingzhulou sections do not show any significant change in vitrinite reflectance. However, coalified woods pellets showed vitrinite reflectance decrease gradually from older to younger parts in the Loho section, Sanshien section and Madagida section. Some of the Implications about the depositional sequence of coastal range can be derived.

  3. Investigation of thermal maturity of lower Palaeozoic hydrocarbon source rocks by means of vitrinite-like maceral reflectance - a Tarim Basin case study

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    Xianming, Xiao; Dehan, Liu; Zufa, Liu; Jiamu, Fu [Chinese Academy of Sciences, Guangzhou (China). Inst. of Geochemistry; Wilkins, R.W.T. [CSIRO Petroluem, North Ryde, NSW (Australia)


    Evolution of the maturity of Chinese lower Palaeozoic sediments has not been satisfactorily accomplished because of the absence of vitrinite and the relatively high level of maturity of the organic matter. In the Tarim Basin, one of the largest petroliferous basins in China, important lower Palaeozoic marine sediments contain a widely distributed type of maceral resembling vitrinite, especially characterised by syndepositional occurrence, elongate shape, homogenous texture and weak anisotropy. The term vitrinite-like maceral is used to describe the maceral in this paper because of insufficient evidence for its origin. Thirty-five lower Palaeozoic source rocks, mainly from five boreholes in the Tarim Basin, have been investigated by organic petrologic methods and a positive correlation between the vitrinite-like maceral reflectance and sample depth has been recognized. This correlation is better than that between bitumen reflectance and depth. Artificial maturation data show that the maturation pathway of vitrinite-like macerals is quite different from that of vitrinite. There is a distinct step in the development of reflectance of vitrinite-like macerals with increasing maturation. By combining the reflectance data from naturally and artificially matured samples, the relationship between vitrinite-like maceral reflectance and vitrinite reflectance can be divided into three stages which are well-represented by three linear regression equations. The equations provide a convenient method to evaluate the maturity of Lower Palaeozoic sediments by allowing an equivalent vitrinite reflectance to be derived from the measured vitrinite-like maceral reflectance. (Author)

  4. Maceral Characteristics and Vitrinite Reflectance Variation of The High Rank Coals, South Walker Creek, Bowen Basin, Australia

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    Asep K. Permana


    Full Text Available DOI: 10.17014/ijog.v8i2.156The Permian coals of the South Walker Creek area, with a vitrinite reflectance (Rvmax of 1.7 to 1.95% (low-volatile bituminous to semi-anthracite, are one of the highest rank coals currently mined in the Bowen Basin for the pulverized coal injection (PCI market. Studies of petrology of this coal seam have identified that the maceral composition of the coals are dominated by inertinite with lesser vitrinite, and only minor amounts of liptinite. Clay minerals, quartz, and carbonates can be seen under the optical microscope. The mineral matter occurs in association with vitrinite and inertinite macerals as syngenetic and epigenetic mineral phases. The irregular pattern of the vitrinite reflectance profile from the top to the bottom of the seam may represent a response in the organic matter to an uneven heat distribution from such hydrothermal influence. Examination of the maceral and vitrinite reflectance characteristics suggest that the mineralogical variation within the coal seam at South Walker Creek may have been controlled by various geological processes, including sediment input into the peat swamp during deposition, mineralogical changes associated with the rank advance process or metamorphism, and/or hydrothermal effects due to post depositional fluid migration through the coal seam.

  5. Vitrinite reflectance geothermometry and apparent heating duration in the Cerro Prieto geothermal field (United States)

    Barker, C.E.; Elders, W.A.


    Vitrinite reflectance measured in immersion oil (Ro) on kerogen extracted from hydrothermally altered mudstones in borehole M-84 at the Cerro Prieto geothermal field exhibit an increase in mean reflectance (Ro) from 0.12 per cent at 0.24 km depth to 4.1 per cent at 1.7 km depth. Downhole temperatures measured over this interval increase from about 60?? to 340??C. These Ro data plotted against temperature fall along an exponential curve with a coefficient of determination of about 0.8. Other boreholes sampled in the field show similar relationships. A regression curve calculated for temperature and Ro in borehole M-105 correctly predicts temperatures in other boreholes within the central portion of the geothermal system. The correlation between the reflectance values and logged temperature, together with consistent temperature estimates from fluid inclusion and oxygen isotope geothermometry, indicates that changes in Ro are an accurate and sensitive recorder of the maximum temperature attained. Therefore, vitrinite reflectance can be used in this geothermal system to predict the undisturbed temperature in a geothermal borehole during drilling before it regains thermal equilibrium. Although existing theoretical functions which relate Ro to temperature and duration of heating are inaccurate, empirical temperature-Ro curves are still useful for geothermometry. A comparison of temperature-Ro regression curves derived from nine boreholes within the Cerro Prieto system suggests that heating across the central portion of the field occurred penecontemporaneously, but varies near margins. Boreholes M-93 and M-94 appear to have cooled from their maximum temperatures, whereas M-3 and Prian-1 have only recently been heated. Comparison of the temperature-Ro data from the Salton Sea, California, geothermal system indicates that the duration of heating has been longer there than at the Cerro Prieto field. ?? 1981.

  6. Evolution of the Cerro Prieto geothermal system as interpreted from vitrinite reflectance under isothermal conditions

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    Barker, C.E. (US Geological Survey, Denver, CO); Pawlewicz, M.J.; Bostick, N.H.; Elders, W.A.


    Temperature estimates from reflectance data in the Cerro Prieto system correlate with modern temperature logs and temperature estimates from fluid inclusion and oxygen isotope geothermometry indicating that the temperature in the central portion of the Cerro Prieto System is now at its historical maximum. Isoreflectance lines formed by contouring vitrinite reflectance data for a given isothermal surface define an imaginary surface that indicates an apparent duration of heating in the system. The 250/sup 0/C isothermal surface has a complex dome-like form suggesting a localized heat source that has caused shallow heating in the central portion of this system. Isoreflectance lines relative to this 250/sup 0/C isothermal surface define a zone of low reflectance roughly corresponding to the crest of the isothermal surface. Comparison of these two surfaces suggest that the shallow heating in the central portion of Cerro Prieto is young relative to the heating (to 250/sup 0/C) on the system margins. Laboratory and theoretical models of hydrothermal convection cells suggest that the form of the observed 250/sup 0/C isothermal surface and the reflectance surface derived relative to it results from the convective rise of thermal fluids under the influence of a regional hydrodynamic gradient that induces a shift of the hydrothermal heating effects to the southwest.

  7. Petrographic and Vitrinite Reflectance Analyses of a Suite of High Volatile Bituminous Coal Samples from the United States and Venezuela (United States)

    Hackley, Paul C.; Kolak, Jonathan J.


    This report presents vitrinite reflectance and detailed organic composition data for nine high volatile bituminous coal samples. These samples were selected to provide a single, internally consistent set of reflectance and composition analyses to facilitate the study of linkages among coal composition, bitumen generation during thermal maturation, and geochemical characteristics of generated hydrocarbons. Understanding these linkages is important for addressing several issues, including: the role of coal as a source rock within a petroleum system, the potential for conversion of coal resources to liquid hydrocarbon fuels, and the interactions between coal and carbon dioxide during enhanced coalbed methane recovery and(or) carbon dioxide sequestration in coal beds.

  8. Vitrinite reflectance data for the Permian Basin, west Texas and southeast New Mexico (United States)

    Pawlewicz, Mark; Barker, Charles E.; McDonald, Sargent


    This report presents a compilation of vitrinite reflectance (Ro) data based on analyses of samples of drill cuttings collected from 74 boreholes spread throughout the Permian Basin of west Texas and southeast New Mexico (fig. 1). The resulting data consist of 3 to 24 individual Ro analyses representing progressively deeper stratigraphic units in each of the boreholes (table 1). The samples, Cambrian-Ordovician to Cretaceous in age, were collected at depths ranging from 200 ft to more than 22,100 ft.The R0 data were plotted on maps that depict three different maturation levels for organic matter in the sedimentary rocks of the Permian Basin (figs. 2-4). These maps show depths at the various borehole locations where the R0 values were calculated to be 0.6 (fig. 2), 1.3 (fig. 3), and 2.0 (fig. 4) percent, which correspond, generally, to the onset of oil generation, the onset of oil cracking, and the limit of oil preservation, respectively.The four major geologic structural features within the Permian Basin–Midland Basin, Delaware Basin, Central Basin Platform, and Northwest Shelf (fig. 1) differ in overall depth, thermal history and tectonic style. In the western Delaware Basin, for example, higher maturation is observed at relatively shallow depths, resulting from uplift and eastward basin tilting that began in the Mississippian and ultimately exposed older, thermally mature rocks. Maturity was further enhanced in this basin by the emplacement of early and mid-Tertiary intrusives. Volcanic activity also appears to have been a controlling factor for maturation of organic matter in the southern part of the otherwise tectonically stable Northwest Shelf (Barker and Pawlewicz, 1987). Depths to the three different Ro values are greatest in the eastern Delaware Basin and southern Midland Basin. This appears to be a function of tectonic activity related to the Marathon-Ouachita orogeny, during the Late-Middle Pennsylvanian, whose affects were widespread across the Permian

  9. Overburden and physical properties in the Marathon fold and thrust belt, West Texas, using conodont thermal maturity and vitrinite reflectance

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    Merrifield, G.T. Jr. (Texas A and M Univ., College Station, TX (United States). Center for Tectonophysics and Ocean Drilling Program)


    Distribution of Ordovician conodonts used in this study covers the southern two-thirds of the 2,400 km[sup 2] in the exposed thrust belt. Conodont color alteration indices (CAI) vary from 1.5 in the northwest to 3.0 eastward and 4.0--4.5 in the extreme southeast. These variations correlate with the 3 km increase in stratigraphic overburden from west to east in the accretionary rocks (Mississippian to Mid Pennsylvanian). In the western exposures, CAI increase southward to 2.0--2.5 within the Dagger Flat structural culmination and decrease to 1.0--1.5 further southward. Increased overburden due to structural thickening explains the CAI increase within the culmination. In the northern one-third of the exposed thrust belt, CAI from the Dimple formation (Mid Pennsylvanian) decrease northward from 2.5 to 1.0--1.5. Neither restored stratigraphic overburden nor local intrusions explain the elevated CAI value of 2.5. Extrapolation of the vitrinite reflectance gradient to the 0.2% value in a well less than 10 km east of this location indicate that between 2.5 and 4.3 km of overburden has been eroded. Structural thickening accounts for at least some of the elevated thermal maturity in this area. Vitrinite reflectance gradients are greater in the accretionary prism strata than in the older basinal facies (Upper Cambrian to Lower Mississippian). Since both facies are shale-rich, lithology alone plays little role in thermal conductivity and maturity variations. Instead, the age of compaction (and possibly undercompaction) relative to the times of thrusting subaerial exposure and erosion, and preservation of maximum thermal maturity are a more important factor. There is a slight discontinuous increase in the thermal maturity across the basal thrust, which is not explained by lithologic variations. Above and below the basal thrust, vitrinite gradients increase and is best explained by induced fracture permeability and flow of hot fluids.

  10. Organic metamorphism in the California petroleum basins; Chapter A, Rock-Eval and vitrinite reflectance (United States)

    Price, Leigh C.; Pawlewicz, Mark J.; Daws, Ted A.


    The results of ROCK-EVAL and vitrinite reflectance analyses of a large sample base from more than 70 wells located in three oil-rich California petroleum basins are reported. The cores from these wells have a wide range of present-day burial temperatures (40 ? to 220 ? C). The rocks in these basins were deposited under highly variable conditions, sometimes resulting in substantially different organic matter (OM) types in rocks tens of meters vertically apart from each other in one well. The kinetic response of these different OM types to equivalent wellknown burial histories is a pivotal point of this study. In the Los Angeles and Ventura Basins, rock organic-richness significantly increased with depth, as did kerogen hydrogen content, and the percentage of fine-grained versus coarsegrained rocks. The shales in these basins are perceived as containing primarily hydrogen-rich amorphous OM. In actuality, the shallowest 2,000 to 3,000 m of rocks in the basins, and at least the upper 6,000 m of rocks in parts of the Los Angeles Basin central syncline, are dominated by type III/IV OM. In the Los Angeles Basin, mainstage hydrocarbon (HC) generation commences in the type III/IV OM at present-day burial temperatures of 85 ? to 110 ? C, most likely around 100 ? C, and is largely complete by 220 ? C. In the Southern San Joaquin Valley Basin, mainstage HC generation commences in type III/IV OM at 150 ? C and is also largely complete by 220 ? C. In the Ventura Basin, mainstage HC generation commences above 140 ? C in type III/IV OM. The apparent lower temperatures for commencement of HC generation in the Los Angeles Basin are attributed to the fact that parts of the basin were cooled from maximal burial temperatures by increased meteoric water flows during the last glaciations. All aspects of organic metamorphism, including mainstage HC generation, are strongly suppressed in rocks with hydrogenrich OM in these basins. For example, ROCK-EVAL data suggest that mainstage HC

  11. Measured reflectance suppressed by thin-film interference of crude oil smeared on glass - as on vitrinite in coal or petroliferous rocks (United States)

    Bostick, Neely


    The tool of measuring "vitrinite reflectance" under a microscope has great value in petroleum exploration and coal utilization, and the reflectance is a simple number, such as 1.4% Ro, with some slight variations depending on technique. Sample collection, preparation and measurement are simple and many sedimentary rocks yield vitrinite. However, the reported number can lead one astray if its origin and quality are not fully understood. I analyze here just one factor, "smear" of crude oil on the polished surface (from the sample), which may reduce reflectance because of thin-film interference. Some other causes of error are listed in an addendum to this note.

  12. Rock-Eval pyrolysis and vitrinite reflectance results from the Sheep Creek 1 well, Susitna basin, south-central Alaska (United States)

    Stanley, Richard G.; Lillis, Paul G.; Pawlewicz, Mark J.; Haeussler, Peter J.


    We used Rock-Eval pyrolysis and vitrinite reflectance to examine the petroleum source potential of rock samples from the Sheep Creek 1 well in the Susitna basin of south-central Alaska. The results show that Miocene nonmarine coal, carbonaceous shale, and mudstone are potential sources of hydrocarbons and are thermally immature with respect to the oil window. In the samples that we studied, coals are more organic-rich and more oil-prone than carbonaceous shales and silty mudstones, which appear to be potential sources of natural gas. Lithologically similar rocks may be present in the deeper parts of the subsurface Susitna basin located west of the Sheep Creek 1 well, where they may have been buried deeply enough to generate oil and (or) gas. The Susitna basin is sparsely drilled and mostly unexplored, and no commercial production of hydrocarbons has been obtained. However, the existence of potential source rocks of oil and gas, as shown by our Rock-Eval results, suggests that undiscovered petroleum accumulations may be present in the Susitna basin.

  13. Integrated Vitrinite Reflectance and Apatite Fission Track Thermocronology of the Lower Karoo rocks in the Moatize Basin, Tete Province, Mozambique. (United States)

    Fernandes, Paulo; Cogné, Nathan; Rodrigues, Bruno; Jorge, Raul; Marques, João


    The Karoo in Mozambique is represented by Late Carboniferous to Late Triassic sediments that were deposited in rift basins that fringe or developed between Proterozoic cratons. In Tete Province, central-west Mozambique, the Karoo is well represented along the Zambezi river valley forming several intra-cratonic basins separated by horsts consisting of igneous and high grade metamorphic Proterozoic rocks. One of the main horst blocks is located between the Cahora Bassa region and Tete city, separating the Middle Zambezi Basin and the Lower Zambezi Basin. The area of study is located in the Moatize Basin, one of many small basins that form the Lower Zambezi Basin. The stratigraphy of this basin consists of several sedimentary formations that record changes in depositional environment and palaeoclimate from glacial (Vúzi Formation - Lower Permian) at the base, through wet to temperate in the middle (Moatize Formation - Lower Permian), to warm arid at the top of the succession (Matinde and Cádzi formations - Middle to Upper Permian). The Upper Karoo volcanics of Early Jurassic age do not crop out in the Moatize Basin. One of the most remarkable characteristics of the Moatize Basin is the richness of coal deposits present in the Lower Permian Moatize Formation. Two coal exploration boreholes (DW123 - T.D. 489 m and DW132 - T.D. 516 m) drilled in the Moatize Basin were studied by means of vitrinite reflectance (VR) and apatite fission track analysis (AFTA), in order to assess their burial and uplift histories. The two boreholes intersected only Moatize Formation lithologies. VR increases in the two borehole sections from ca. 1.30-1.32 % Ro at the top to ca. 1.52-1.69 % Ro at the bottom, indicating medium to low volatile coal rank. Modelled VR data from the two boreholes indicate palaeogeothermal gradients between 40 and 56ºC/km, possible related to basin forming processes. Fission track ages increase from 84 Ma and 102 Ma at the bottom to 138 Ma and 146 Ma at the top

  14. The thermal history of the Karoo Moatize-Minjova Basin, Tete Province, Mozambique: An integrated vitrinite reflectance and apatite fission track thermochronology study (United States)

    Fernandes, Paulo; Cogné, Nathan; Chew, David M.; Rodrigues, Bruno; Jorge, Raul C. G. S.; Marques, João; Jamal, Daud; Vasconcelos, Lopo


    The Moatize-Minjova Basin is a Karoo-aged rift basin located in the Tete Province of central Mozambique along the present-day Zambezi River valley. In this basin the Permian Moatize and Matinde formations consist of interbedded carbonaceous mudstones and sandstones with coal seams. The thermal history has been determined using rock samples from two coal exploration boreholes (ca. 500 m depth) to constrain the burial and exhumation history of the basin. Organic maturation levels were determined using vitrinite reflectance and spore fluorescence/colour. Ages and rates of tectonic uplift and denudation have been assessed by apatite fission track analysis. The thermal history was modelled by inverse modelling of the fission track and vitrinite reflectance data. The Moatize Formation attained a coal rank of bituminous coals with low to medium volatiles (1.3-1.7%Rr). Organic maturation levels increase in a linear fashion downhole in the two boreholes, indicating that burial was the main process controlling peak temperature maturation. Calculated palaeogeothermal gradients range from 59 °C/km to 40 °C/km. According to the models, peak burial temperatures were attained shortly (3-10 Ma) after deposition. Apatite fission track ages [146 to 84 Ma (Cretaceous)] are younger than the stratigraphic age. Thermal modelling indicates two episodes of cooling and exhumation: a first period of rapid cooling between 240 and 230 Ma (Middle - Upper Triassic boundary) implying 2500-3000 m of denudation; and a second period, also of rapid cooling, from 6 Ma (late Miocene) onwards implying 1000-1500 m of denudation. The first episode is related to the main compressional deformation event within the Cape Fold Belt in South Africa, which transferred stress northwards on pre-existing transtensional fault systems within the Karoo rift basins, causing tectonic inversion and uplift. During the Mesozoic and most of the Cenozoic the basin is characterized by very slow cooling. The second period

  15. The Paleozoic tectonothermal evolution of the Bachu Uplift of the Tarim Basin, NW China: Constraints from (U-Th)/He ages, apatite fission track and vitrinite reflectance data (United States)

    Qiu, Nansheng; Jiang, Guang; Mei, Qinghua; Chang, Jian; Wang, Shengjun; Wang, Jiyang


    This study uses a new application of the apatite and zircon (U-Th)/He thermochronometry technique to investigate the thermal history and tectonic uplift of sedimentary basins. Based on measured apatite and zircon (U-Th)/He ages, apatite fission track data and equivalent vitrinite reflectance measurements of borehole core samples, the thermal history of the Bachu Uplift of the Tarim Basin was modeled. Our analysis indicates a complicated thermal history in the Bachu Uplift region during the Paleozoic. The thermal gradient initially increased from 28-30 °C/km in the Cambrian period to 30-33 °C/km in the Ordovician period and increased up to 33-34 °C/km in the Silurian period. The thermal gradient began to decrease during the Devonian period and was estimated to be approximately 30 °C/km during the Late Devonian and the Early Carboniferous periods. The low thermal gradient phase was followed by an additional high gradient phase from the Late Carboniferous to the Early Permian when the gradient was approximately 32 °C/km. Thermal gradients in the Paleozoic were substantially different than the present-day gradient (21 °C/km). Tectonothermal modeling results also revealed uplift events in the Bachu Uplift region that shifted from south to north (e.g., ˜150 Ma to ˜100 Ma) and from west to east (e.g., ˜250 Ma to ˜150 Ma). This thermal evolution of the Bachu Uplift is consistent with its tectonic progression. The thermal spike in the Late Carboniferous and Early Permian periods could be related to magmatic activities in the Early Permian period. The Paleozoic thermal history of the Bachu Uplift region of the Tarim Basin could not be reconstructed properly due to a lack of reliable thermal indicators in the Lower Paleozoic successions, and a poor understanding of the thermal evolution of Lower Paleozoic source rocks during the Paleozoic has hindered petroleum exploration in this area. This study provides a new Paleozoic thermal history and shows that the Paleozoic

  16. Macromolecule simulation and CH4 adsorption mechanism of coal vitrinite (United States)

    Yu, Song; Yan-ming, Zhu; Wu, Li


    The microscopic mechanism of interactions between CH4 and coal macromolecules is of significant practical and theoretical importance in CBM development and methane storage. Under periodic boundary conditions, the optimal energy configuration of coal vitrinite, which has a higher torsion degree and tighter arrangement, can be determined by the calculation of molecular mechanics (MM) and molecular dynamics (MD), and annealing kinetics simulation based on ultimate analysis, 13C NMR, FT IR and HRTEM. Macromolecular stabilization is primarily due to the van der Waals energy and covalent bond energy, mainly consisting of bond torsion energy and bond angle energy. Using the optimal configuration as the adsorbent, GCMC simulation of vitrinite adsorption of CH4 is conducted. A saturated state is reached after absorbing 17 CH4s per coal vitrinite molecule. CH4 is preferentially adsorbed on the edge, and inclined to gathering around the branched chains of the inner vitrinite sites. Finally, the adsorption parameters are calculated through first principle DFT. The adsorbability order is as follows: aromatic structure> heteroatom rings > oxygen functional groups. The adsorption energy order is as follows: Top RDF better reflects the adsorption ability and that of [-COOH] is lower than those of [sbnd Cdbnd O] and [Csbnd Osbnd C]. CH4 distributed in the distance of 0.99-16 Å to functional groups in the type of monolayer adsorption and the average distance order manifest as [sbnd Cdbnd O] (1.64 Å) RDF curves. CH4 enriches around [sbnd Cdbnd O] and [Csbnd O-C] whereas is rather dispersed about [-COOH] and [CH3]. Simulation and experiment data are both in strong agreement with the Langmuir and D-A isothermal adsorption model and the D-A model fit better than Langmuir model. Preferential adsorption sites and orientations in vitrinite are identical to those of graphite/graphene. However, the energy of the most preferential location is much lower than that of graphite/graphene. CH4

  17. Simulations and experimental investigations of the competitive adsorption of CH4 and CO2 on low-rank coal vitrinite. (United States)

    Yu, Song; Bo, Jiang; Jiahong, Li


    The mechanism for the competitive adsorption of CH4 and CO2 on coal vitrinite (DV-8, maximum vitrinite reflectance R o,max = 0.58%) was revealed through simulation and experimental methods. A saturated state was reached after absorbing 17 CH4 or 22 CO2 molecules per DV-8 molecule. The functional groups (FGs) on the surface of the vitrinite can be ranked in order of decreasing CH4 and CO2 adsorption ability as follows: [-CH3] > [-C=O] > [-C-O-C-] > [-COOH] and [-C-O-C-] > [-C=O] > [-CH3] > [-COOH]. CH4 and CO2 distributed as aggregations and they were both adsorbed at the same sites on vitrinite, indicating that CO2 can replace CH4 by occupying the main adsorption sites for CH4-vitrinite. High temperatures are not conducive to the adsorption of CH4 and CO2 on vitrinite. According to the results of density functional theory (DFT) and grand canonical Monte Carlo (GCMC) calculations, vitrinite has a higher adsorption capacity for CO2 than for CH4, regardless of whether a single-component or binary adsorbate is considered. The equivalent adsorption heat (EAH) of CO2-vitrinite (23.02-23.17) is higher than that of CH4-vitrinite (9.04-9.40 kJ/mol). The EAH of CO2-vitrinite decreases more rapidly with increasing temperature than the EAH of CH4-vitrinite does, indicating in turn that the CO2-vitrinite bond weakens more quickly with increasing temperature than the CH4-vitrinite bond does. Simulation data were found to be in good accord with the corresponding experimental results.

  18. Postimpact heat conduction and compaction-driven fluid flow in the Chesapeake Bay impact structure based on downhole vitrinite reflectance data, ICDP-USGS Eyreville deep core holes and Cape Charles test holes (United States)

    Malinconico, M.L.; Sanford, W.E.; Wright, Horton W.J.J.


    Vitrinite reflectance data from the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville deep cores in the centralcrater moat of the Chesapeake Bay impact structure and the Cape Charles test holes on the central uplift show patterns of postimpact maximum-temperature distribution that result from a combination of conductive and advective heat flow. Within the crater-fill sediment-clast breccia sequence at Eyreville, an isoreflectance (-0.44% Ro) section (525-1096 m depth) is higher than modeled background coastal-plain maturity and shows a pattern typical of advective fluid flow. Below an intervening granite slab, a short interval of sediment-clast breccia (1371-1397 m) shows a sharp increase in reflectance (0.47%-0.91% Ro) caused by conductive heat from the underlying suevite (1397-1474 m). Refl ectance data in the uppermost suevite range from 1.2% to 2.1% Ro. However, heat conduction alone is not sufficient to affect the temperature of sediments more than 100 m above the suevite. Thermal modeling of the Eyreville suevite as a 390 ??C cooling sill-like hot rock layer supplemented by compaction- driven vertical fluid flow (0.046 m/a) of cooling suevitic fluids and deeper basement brines (120 ??C) upward through the sediment breccias closely reproduces the measured reflectance data. This scenario would also replace any marine water trapped in the crater fill with more saline brine, similar to that currently in the crater, and it would produce temperatures sufficient to kill microbes in sediment breccias within 450 m above the synimsuevite. A similar downhole maturity pattern is present in the sediment-clast breccia over the central uplift. High-reflectance (5%-9%) black shale and siltstone clasts in the suevite and sediment-clast breccia record a pre-impact (Paleozoic?) metamorphic event. Previously published maturity data in the annular trough indicate no thermal effect there from impact-related processes. ?? 2009 The

  19. Investigation of the existence of coal matrix effects on the hydroliquefaction of vitrinites derived from low rank Spanish coals

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    Cebolla, V.L.; Martinez, M.T.; Prado, J.G.; Miranda, J.L.; Fernandez, I.; Benito, A.M. (Instituto de Carboquimica, Zaragoza (Spain))


    Two lignites (Mequinenza, Spain) and two subbituminous coals (Teruel, Spain), their demineralized derivatives (HCl/HF+HCl) and their corresponding derived vitrinite concentrates were submitted to hydroliquefaction in tetralin in fixed conditions to study a possible synergism of vitrinite concentrates in the original coal matrix. Sufficiently pure amounts of vitrinite concentrates were isolated by a method based on differential centrifugation in CsCl. The coals were characterized by densimetric and petrographic analyses including reflectance-frequency distributions. A synergism for vitrinite concentrates related to the demineralized coals has not been found here because all the vitrinite concentrates, once separated, have similar or higher reactivity than in the corresponding original coal matrix. On the other hand, the studied lignite-derived vitrinite concentrates have proved to be much more reactive than the subbituminous-derived ones. Displacements of Absorbance-Density curves and maxima toward higher densities (densimetric analyses data) and appearance of V-4 vitrinite type structures (coal reflectograms) in the case of the subbituminous coals imply differences in chemical structures for the lignite and the subbituminous derived vitrinite concentrates which could explain the differences in reactivity. 22 refs., 3 figs., 2 tabs.

  20. Petrography of Permian "Gondwana" coals from boreholes in northwestern Bangladesh, based on semiautomated reflectance scanning (United States)

    Bostick, N.H.; Betterton, W.J.; Gluskoter, H.J.; Nazrul, Islam M.


    Drilling through Quaternary alluvium and Tertiary cover at low-gravity anomalies in northwestern Bangladesh showed the presence of Permian sedimentary rocks in depressions that may be as much as a thousand meters deep in the crystalline basement. These Permian strata include low-sulfur, high-volatile bituminous coals in beds as thick as 15 m. The maceral group composition of these coals was determined by semiautomated reflectance scanning with a motorized microscope stage, rather than by point counting. This method was chosen to give objectively recorded raw analytical data and to provide a graphical picture of each sample. The coals are mostly "Gondwana" type (poorly layered "plum pudding" with abundant minerals and inertinite in a vitrinite groundmass) that would be classed as semi-dull (inerto-gelitite) coals. However, six samples have more than 70% vitrinite. None of the samples would be classed as sapropelic (liptinitic). The upper, middle, and lower main seams in borehole GDH-45 were sampled in 10 benches (0.1-3 m thick) each. Inertinite ranges from 7 to 100 vol% (mineral free basis) in individual benches, but composite seam averages are 41, 54 and 67%. Inertinite increases toward the top of two main seams so the bottom would yield the most valuable first mine slices. Some benches with extremely high inertinite content, such as the top 7 m of the lower thick seam, might be mined specially for blending with foreign low-inert coals to increase coke strength. The free swelling index reaches 7.5 in several vitrinite-rich benches, which can indicate good coking coal. Much of the vitrinite is fluorescent, which indicates secondary bituminization characteristic of vitrinite in good coking coals. Ash yields range from 8 to 52%, with composite seam averages of 15, 14 and 24%. Rare visible pyrite is in veinlets or small nodules; framboids and dispersed pyrite are absent. In borehole GDH-40 near Barapukuria (200-500 m depth), the mean random reflectance of vitrinite "A

  1. Macromolecule simulation and CH{sub 4} adsorption mechanism of coal vitrinite

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Song, E-mail: [School of Resources and Earth Science, China University of Mining & Technology, Xuzhou 221116 (China); Key Laboratory of Coal bed Methane Resource & Reservoir Formation Process, Ministry of Education, Xuzhou 221008 (China); Yan-ming, Zhu; Wu, Li [School of Resources and Earth Science, China University of Mining & Technology, Xuzhou 221116 (China); Key Laboratory of Coal bed Methane Resource & Reservoir Formation Process, Ministry of Education, Xuzhou 221008 (China)


    Highlights: • Molecular model of single maceral vitrinite was obtained by {sup 13}C NMR, FT IR and HRTEM. • An optimal configuration was obtained through calculation of MM and MD. • The adsorption parameters for methane and vitrinite were determined with DFT and GCMC. - Abstract: The microscopic mechanism of interactions between CH{sub 4} and coal macromolecules is of significant practical and theoretical importance in CBM development and methane storage. Under periodic boundary conditions, the optimal energy configuration of coal vitrinite, which has a higher torsion degree and tighter arrangement, can be determined by the calculation of molecular mechanics (MM) and molecular dynamics (MD), and annealing kinetics simulation based on ultimate analysis, {sup 13}C NMR, FT IR and HRTEM. Macromolecular stabilization is primarily due to the van der Waals energy and covalent bond energy, mainly consisting of bond torsion energy and bond angle energy. Using the optimal configuration as the adsorbent, GCMC simulation of vitrinite adsorption of CH{sub 4} is conducted. A saturated state is reached after absorbing 17 CH{sub 4}s per coal vitrinite molecule. CH{sub 4} is preferentially adsorbed on the edge, and inclined to gathering around the branched chains of the inner vitrinite sites. Finally, the adsorption parameters are calculated through first principle DFT. The adsorbability order is as follows: aromatic structure> heteroatom rings > oxygen functional groups. The adsorption energy order is as follows: Top < Bond < Center, Up < Down. The order of average RDF better reflects the adsorption ability and that of [-COOH] is lower than those of [−C=O] and [C−O−C]. CH{sub 4} distributed in the distance of 0.99–16 Å to functional groups in the type of monolayer adsorption and the average distance order manifest as [−C=O] (1.64 Å) < [C−O−C] (1.89 Å) < [−COOH] (3.78 Å) < [-CH{sub 3}] (4.11 Å) according to the average RDF curves. CH{sub 4} enriches

  2. Measurement of reflectance of coal macerals: its automation and significance

    Energy Technology Data Exchange (ETDEWEB)

    Davis, A.


    A prime objective of the Pennsylvania State University's DOE program is the characterization of 1,300 samples of U.S. coals. Reflectance determination plays a major role in meeting this objective, because it is used as an accurate rank index both to select coals for testing and to investigate property-behavior interrelationships using the Penn State/DOE Coal Data Base. Reflectances of coal macerals are related to their refractive and absorptive indices by the Beer equation; the refractive index of the medium and the wavelength of light need to be specified. Determinations usually are made in immersion oil at 546 nm. Properties of vitrinite make it the most suitable maceral for these measurements, but the variety of vitrinite selected may depend upon the intended application. Vitrinite reflectance is considered to be dependent upon the degree of aromatization of its structural units. Although some of the earlier investigators believed that the reflectance of coals increased in a discontinuous, stepped manner as their rank increased, the bulk of assembled data suggests that the change is continuous. Some recent results indicate that there may be more than one coalification track for coals with different geological histories, resulting in displacement from the general trend. Several techniques have been employed to determine the optical properties of coal constituents. Usual comparative method involves the use of a microscope photometer to compare the intensity of light reflected by particles within a polished pellet of coal to that of a glass or synthetic mineral standard. Because coal is anisotropic it is common to measure either maximum reflectance in polarized light or random reflectance in non-polarized light. Various eqipment modifications and accessories have been used to improve the ease of measuring maximum reflectance.

  3. Molecular model and ReaxFF molecular dynamics simulation of coal vitrinite pyrolysis. (United States)

    Li, Wu; Zhu, Yan-ming; Wang, Geoff; Wang, Yang; Liu, Yu


    Vitrinite in coal, the mainly generating methane maceral, plays an important role in hydrocarbon generation of coal. This study aims at obtaining products formation mechanism of vitrinite pyrolysis, and hence determining the chemical bond, molecular liquefaction activity, and reactions mechanism of methane and C2-4 during pyrolysis. The ReaxFF molecular dynamics (MD) simulation was carried out at temperature of 1500 K in order to investigate the mechanism of vitrinite pyrolysis. Initially, a minimum energy conformational structure model was constrained by a combination of elemental and carbon-13 nuclear magnetic resonance ((13)C NMR) literature data. The model analysis shows the chemical and physical parameters of vitrinite pyrolysis are broadly consistent with the experimental data. Based on the molecular model, ReaxFF MD simulations further provide information of unimolecule such as bond length, and chemical shift, and hence the total population and energy of main products. Molecules bond and pyrolysis fragments, based on active bond analyzed, revealed pyrolysis products of single vitrinite molecule with aliphatic C-C bond, especially ring and chain aliphatic as liquefaction activity. The molecular cell whose density is 0.9 g/cm(3) with lowest energy accords with the experimental density 1.33 g/cm(3). The content of main products after pyrolysis, classifying as CH4, H2O, and H2, was changed along with the increasing temperature. The gas molecule, fragments and generation pathways of CO2, H2, CH4, and C2H6 were also elucidated. These results show agreement with experimental observations, implying that MD simulation can provide reasonable explanation for the reaction processes involved in coal vitrinite pyrolysis. Thus the mechanism of coal hydrocarbon generation was revealed at the molecular level.

  4. Studies on structural coal characteristics. Part 2. Parameters of electron absorption by coal and their links with reflectivity

    Energy Technology Data Exchange (ETDEWEB)

    Popov, V.K.; Rys' yanova, N.D.; Plastun, S.N.


    Problems associated with determining black coal rank on the basis of vitrinite reflectivity are discussed. Correlations between coal rank and vitrinite reflectivity are analyzed. Factors which disturb coal rank analyses are reviewed. A method for determining absorption spectra in ultraviolet spectra, visible spectra and infrared spectra using radiation which is diffused-dispersed by coal is evaluated. The method is used for investigations into nature of changes in parameters of electron spectra of vitrinites depending on coal rank, which is determined on the basis of vitrinite reflectivity. Method for coal sample preparation, measurements using the MPS-5000 system and evaluating measurement results are discussed. Investigation results are given in 3 schemes. Correlations between radiation absorption and coal microstructure are analyzed. Recommendations are made for use of the method in black coal rank determination.

  5. Reflection principles for biased random walks and application to escape time distributions (United States)

    Khantha, M.; Balakrishnan, V.


    We present a reflection principle for an arbitrary biased continuous time random walk (comprising both Markovian and non-Markovian processes) in the presence of a reflecting barrier on semi-infinite and finite chains. For biased walks in the presence of a reflecting barrier this principle (which cannot be derived from combinatorics) is completely different from its familiar form in the presence of an absorbing barrier. The result enables us to obtain closed-form solutions for the Laplace transform of the conditional probability for biased walks on finite chains for all three combinations of absorbing and reflecting barriers at the two ends. An important application of these solutions is the calculation of various first-passage-time and escape-time distributions. We obtain exact results for the characteristic functions of various kinds of escape time distributions for biased random walks on finite chains. For processes governed by a long-tailed event-time distribution we show that the mean time of escape from bounded regions diverges even in the presence of a bias—suggesting, in a sense, the absence of true long-range diffusion in such "frozen" processes.

  6. Reflections

    Indian Academy of Sciences (India)

    REFLECTIONS. A freer life and independent work made of the quiet, dreamy boy a happy, outgoing, universally liked young man. He also began to familiarize himself with classical German literature. Though at first he was acquainted only with Milan and Pavia, Italy made a great impression on him even with this limitation.

  7. Students' satisfaction with general practitioners' feedback to their reflective writing: a randomized controlled trial. (United States)

    Kiss, Alexander; Steiner, Claudia; Grossman, Paul; Langewitz, Wolf; Tschudi, Peter; Kiessling, Claudia


    Reflective Writing (RW) is increasingly being implemented in medical education. Feedback to students' reflective writing (RW) is essential, but resources for individualized feedback often lack. We aimed to determine whether general practitioners (GPs) teaching students clinical skills could also provide feedback to RW and whether an instruction letter specific to RW feedback increases students' satisfaction. GPs were randomized to the two study arms using block randomization. GPs in both groups received an instruction letter on giving students feedback on clinical skills. Additionally, intervention group GPs received specific instructions on providing feedback to students' RW. Students completed satisfaction questionnaires on feedback received on clinical skills and RW. T-tests were employed for all statistical analysis to compare groups. Eighty-three out of 134 physicians participated: 38 were randomized to the control, 45 to the intervention group. Students were very satisfied with the feedback on RW and clinical skills regardless of tutors' group allocation. A specific instruction letter had no additional effect on students' satisfaction. Based on student satisfaction, GPs who give students feedback on clinical skills are also well suited to provide feedback on RW. This approach can facilitate the introduction of mandatory RW into the regular medical curriculum.

  8. Wave reflection from randomly inhomogeneous ionospheric layer: 1. The method of describing the wavefield in a reflecting layer with random irregularities (United States)

    Tinin, Mikhail


    It has been previously proposed to describe wave propagation in inhomogeneous media in a small-angle approximation with the aid of a double weighted Fourier transform (DWFT) method. This method agrees with the methods of geometrical optics, smooth perturbations, and phase screen in domains of their applicability; therefore, it can be employed to solve direct and inverse problems of radio wave propagation in multiscale inhomogeneous ionospheric plasma. In this paper, for the DWFT wide-angle generalization a wave equation is preliminary reduced using the Fock proper-time method to a parabolic equation that then is solved by the DWFT method. The resulting solution is analyzed for the case of wave reflection and scattering by a layer with random irregularities and linear profile of average permittivity. We show the transformation of this solution into strict results in the absence of irregularities and in the single-scatter approximation, including backscattering, during weak phase fluctuations. Under certain conditions, the solution takes the form of the small-angle DWFT with respect to refraction in the layer and backscatter effects. Spatial processing in source and observer coordinates brings a beam of received waves into one wave without amplitude fluctuations, which allows an increase in resolution of vertical ionospheric sounding systems.

  9. Published methodological quality of randomized controlled trials does not reflect the actual quality assessed in protocols (United States)

    Mhaskar, Rahul; Djulbegovic, Benjamin; Magazin, Anja; Soares, Heloisa P.; Kumar, Ambuj


    Objectives To assess whether reported methodological quality of randomized controlled trials (RCTs) reflect the actual methodological quality, and to evaluate the association of effect size (ES) and sample size with methodological quality. Study design Systematic review Setting Retrospective analysis of all consecutive phase III RCTs published by 8 National Cancer Institute Cooperative Groups until year 2006. Data were extracted from protocols (actual quality) and publications (reported quality) for each study. Results 429 RCTs met the inclusion criteria. Overall reporting of methodological quality was poor and did not reflect the actual high methodological quality of RCTs. The results showed no association between sample size and actual methodological quality of a trial. Poor reporting of allocation concealment and blinding exaggerated the ES by 6% (ratio of hazard ratio [RHR]: 0.94, 95%CI: 0.88, 0.99) and 24% (RHR: 1.24, 95%CI: 1.05, 1.43), respectively. However, actual quality assessment showed no association between ES and methodological quality. Conclusion The largest study to-date shows poor quality of reporting does not reflect the actual high methodological quality. Assessment of the impact of quality on the ES based on reported quality can produce misleading results. PMID:22424985

  10. Reflective random indexing for semi-automatic indexing of the biomedical literature. (United States)

    Vasuki, Vidya; Cohen, Trevor


    The rapid growth of biomedical literature is evident in the increasing size of the MEDLINE research database. Medical Subject Headings (MeSH), a controlled set of keywords, are used to index all the citations contained in the database to facilitate search and retrieval. This volume of citations calls for efficient tools to assist indexers at the US National Library of Medicine (NLM). Currently, the Medical Text Indexer (MTI) system provides assistance by recommending MeSH terms based on the title and abstract of an article using a combination of distributional and vocabulary-based methods. In this paper, we evaluate a novel approach toward indexer assistance by using nearest neighbor classification in combination with Reflective Random Indexing (RRI), a scalable alternative to the established methods of distributional semantics. On a test set provided by the NLM, our approach significantly outperforms the MTI system, suggesting that the RRI approach would make a useful addition to the current methodologies.

  11. Reflective Random Indexing and indirect inference: a scalable method for discovery of implicit connections. (United States)

    Cohen, Trevor; Schvaneveldt, Roger; Widdows, Dominic


    The discovery of implicit connections between terms that do not occur together in any scientific document underlies the model of literature-based knowledge discovery first proposed by Swanson. Corpus-derived statistical models of semantic distance such as Latent Semantic Analysis (LSA) have been evaluated previously as methods for the discovery of such implicit connections. However, LSA in particular is dependent on a computationally demanding method of dimension reduction as a means to obtain meaningful indirect inference, limiting its ability to scale to large text corpora. In this paper, we evaluate the ability of Random Indexing (RI), a scalable distributional model of word associations, to draw meaningful implicit relationships between terms in general and biomedical language. Proponents of this method have achieved comparable performance to LSA on several cognitive tasks while using a simpler and less computationally demanding method of dimension reduction than LSA employs. In this paper, we demonstrate that the original implementation of RI is ineffective at inferring meaningful indirect connections, and evaluate Reflective Random Indexing (RRI), an iterative variant of the method that is better able to perform indirect inference. RRI is shown to lead to more clearly related indirect connections and to outperform existing RI implementations in the prediction of future direct co-occurrence in the MEDLINE corpus. 2009 Elsevier Inc. All rights reserved.

  12. Standardization of reflectance measurements in dispersed organic matter: results of an exercise to improve interlaboratory agreement (United States)

    Hackley, Paul C.; Araujo, Carla Viviane; Borrego, Angeles G.; Bouzinos, Antonis; Cardott, Brian; Cook, Alan C.; Eble, Cortland; Flores, Deolinda; Gentzis, Thomas; Gonçalves, Paula Alexandra; Filho, João Graciano Mendonça; Hámor-Vidó, Mária; Jelonek, Iwona; Kommeren, Kees; Knowles, Wayne; Kus, Jolanta; Mastalerz, Maria; Menezes, Taíssa Rêgo; Newman, Jane; Pawlewicz, Mark; Pickel, Walter; Potter, Judith; Ranasinghe, Paddy; Read, Harold; Reyes, Julito; Rodriguez, Genaro De La Rosa; de Souza, Igor Viegas Alves Fernandes; Suarez-Ruiz, Isabel; Sýkorová, Ivana; Valentine, Brett J.


    Vitrinite reflectance generally is considered the most robust thermal maturity parameter available for application to hydrocarbon exploration and petroleum system evaluation. However, until 2011 there was no standardized methodology available to provide guidelines for vitrinite reflectance measurements in shale. Efforts to correct this deficiency resulted in publication of ASTM D7708: Standard test method for microscopical determination of the reflectance of vitrinite dispersed in sedimentary rocks. In 2012-2013, an interlaboratory exercise was conducted to establish precision limits for the D7708 measurement technique. Six samples, representing a wide variety of shale, were tested in duplicate by 28 analysts in 22 laboratories from 14 countries. Samples ranged from immature to overmature (0.31-1.53% Ro), from organic-lean to organic-rich (1-22 wt.% total organic carbon), and contained Type I (lacustrine), Type II (marine), and Type III (terrestrial) kerogens. Repeatability limits (maximum difference between valid repetitive results from same operator, same conditions) ranged from 0.03-0.11% absolute reflectance, whereas reproducibility limits (maximum difference between valid results obtained on same test material by different operators, different laboratories) ranged from 0.12-0.54% absolute reflectance. Repeatability and reproducibility limits degraded consistently with increasing maturity and decreasing organic content. However, samples with terrestrial kerogens (Type III) fell off this trend, showing improved levels of reproducibility due to higher vitrinite content and improved ease of identification. Operators did not consistently meet the reporting requirements of the test method, indicating that a common reporting template is required to improve data quality. The most difficult problem encountered was the petrographic distinction of solid bitumens and low-reflecting inert macerals from vitrinite when vitrinite occurred with reflectance ranges overlapping

  13. Virtual Reality Reflection Therapy Improves Balance and Gait in Patients with Chronic Stroke: Randomized Controlled Trials. (United States)

    In, Taesung; Lee, Kyeongjin; Song, Changho


    BACKGROUND Virtual reality reflection therapy (VRRT) is a technically enhanced version of the mirror therapy concept. The aim of this study was to investigate whether VRRT could improve the postural balance and gait ability of patients with chronic stroke. MATERIAL AND METHODS Twenty-five patients with chronic stroke were randomly allocated into the VRRT group (n=13) and the control group (n=12). The participants in both groups performed a conventional rehabilitation program for 30 minutes. The VRRT group also performed a VRRT program for 30 minutes, five times a week for 4 weeks. The control group performed conventional rehabilitation program and a placebo VRRT program. Outcome measures included Berg Balance Scale (BBS), the Functional Reaching Test (FRT), and the Timed Up and Go (TUG) test (for dynamic balance ability), postural sway (for static balance ability), and 10 meter walking velocity (10 mWV) for gait ability. RESULTS There were statistically significant improvements in the VRRT group compared with the control group for BBS, FRT, TUG, postural sway (mediolateral sway distance with eyes open and eyes closed, anteroposterior and total sway distance with eyes open but not with eyes closed), and 10 mWV (prehabilitation program for patients with chronic stroke might be even more beneficial than conventional rehabilitation program alone in improving affected lower limb function. Future studies should investigate the effectiveness of VRRT with optimal patient selection, and duration and intensity of training.

  14. Reflectance measurements of zooclasts and solid bitumen in Lower Paleozoic shales, southern Scandinavia

    DEFF Research Database (Denmark)

    Petersen, Henrik I.; Schovsbo, Niels H.; Nielsen, Arne Thorshøj


    Reflectance measurements have been carried out on zooclasts (graptolites, chitinozoans, and vase-shaped microfossils) and other organic particles (vitrinite-like particles, porous/granular vitrinite-like particles, and solid bitumen) in Middle Cambrian to Upper Silurian shales from central and so...... to that of graptolites at the same level of maturity. Reflectance measurements of solid bitumen are a poor maturity indicator, probably because bitumen can have various origins and morphologies and it may not be indigenous to the host rock. (C) 2013 Elsevier B.V. All rights reserved....

  15. Reflecting peer-support groups in the prevention of stress and burnout: randomized controlled trial. (United States)

    Peterson, Ulla; Bergström, Gunnar; Samuelsson, Mats; Asberg, Marie; Nygren, Ake


    This paper is a report of a study to test the effect of participating in a reflecting peer-support group on self-reported health, burnout and on perceived changes in work conditions. Stress-related conditions are one of the most common causes for long-term sick-leave. There is limited evidence for the effectiveness of person-directed interventions aimed at reducing stress levels in healthcare workers. Prior research in the relationship between support and burnout show somewhat inconsistent results. A randomized controlled trial with peer-support groups as the intervention was conducted with 660 healthcare workers scoring above the 75th percentile on the exhaustion dimension of the Oldenburg Burnout Inventory. One hundred and fifty-one (22.9%) agreed to participate. The intervention started in 2002 with 51 participants (96.1% were women), 80 of whom constituted the control group. Potential differences in outcome measures 12 months after the intervention were compared using ancova, and data collected was completed in 2004. Qualitative content analyses were used to analyse reported experiences from group participation. Statistically significant intervention effects were found for general health, perceived quantitative demands at work, participation and development opportunities at work and in support at work. Seven categories of experiences from participating were identified: talking to others in a similar situation, knowledge, sense of belonging, self-confidence, structure, relief of symptoms and behavioural change. Peer-support groups using a problem-based method could be a useful and comparatively inexpensive tool in alleviating work-related stress and burnout.

  16. Constitution of Drop-Tube-Generated Coal Chars from Vitrinite- and Inertinite-Rich South African Coals

    Energy Technology Data Exchange (ETDEWEB)

    Louw, Enette B.; Mitchell, Gareth D.; Wang, Juan; Winans, Randall E.; Mathews, Jonathan P.


    The structural transformations of coal and the resultant char morphologies are strongly dependent on the initial structure and degree of thermoplasticity achieved during coal-to-char transition. These are a function of petrographic composition, rank, particle size, and heating rate and strongly affect combustion behavior. This study compares the devolatilization and subsequent combustion behavior of an inertinite-rich (87.7% dmmf) and a vitrinite-rich (91.8% dmmf) South African coal, wet-screened to a narrow particle size distribution of 200 x 400 mesh. Pyrolysis chars were generated under rapid-heating conditions (104-105 °C/s) in a drop-tube reactor to closely resemble chars generated in pulverized combustion conditions. The inertinite-rich coal took ~ 400 ms to devolatilize in the drop-tube, compared to only ~ 240 ms for the vitrinite-rich sample. The chemical and physical structure (the constitution) of the chars were investigated through a range of chemical, physical, and optical characteristics including the maceral differences, and high ash yields. To evaluate the combustion reactivity non-isothermal burn-out profiles were obtained through thermogravimetrical analyses (TGA) in air. The vitrinite-rich char had on average 20% higher reaction rates than the inertinite-rich char under the various combustion conditions. The char samples were de-ashed with HCl and HF acid which resulted in an increase in combustion reactivity. The maximum reaction rate of the high-ash (36% ash yield) inertinite-rich char increased with 80% after de-ashing. While the vitrinite-rich char with an ash yield of 15%, had a 20% increase in reactivity after de-ashing. The ash acted as a barrier, and the removal of ash most likely increased the access to reactive surface area. The chemical and physical structures of the chars were characterized through a range of different analytical techniques to quantify the factors contributing to reactivity differences. The morphologies of the chars

  17. Investigation of structural characteristics of coals. Two parameters of the electron absorption of coals and their connection with reflectivity

    Energy Technology Data Exchange (ETDEWEB)

    Popov, V.K.; Rys' yanova, N.D.; Plastun, S.N.


    A method was developed for obtaining reflectance spectra of coals in the ultraviolet, visible and near-infrared regions utilising diffuse scattering of light. This enabled the determination of electron spectra to be considerably simplified. The method was used to evaluate changes in electron spectra of vitrinites with rank, using reflectance measurement as the determinant.

  18. Thermal maturity patterns in the Ordovician and Devonian of Pennsylvania using conodont color alteration index (CAI) and vitrinite reflectance (%Ro) (United States)

    Repetski, J.E.; Ryder, R.T.; Harper, J.A.; Trippi, M.H.


    This new series of maps enhances previous thermal maturity maps in Pennsylvania by establishing: 1) new subsurface CAI data points for the Ordovician and Devonian and 2) new %Ro and Rock Eval subsurface data points for Middle and Upper Devonian black shale units. Thermal maturity values for the Ordovician and Devonian strata are of major interest because they contain the source rocks for most of the oil and natural gas resources in the basin. Thermal maturity patterns of the Middle Ordovician Trenton Group are evaluated here because they closely approximate those of the overlying Ordovician Utica Shale that is believed to be the source rock for the regional oil and gas accumulation in Lower Silurian sandstones and for natural gas fields in fractured dolomite reservoirs of the Ordovician Black River-Trenton Limestones. Improved CAI-based thermal maturity maps of the Ordovician are important to identify areas of optimum gas generation from the Utica Shale and to provide constraints for interpreting the origin of oil and gas in the Lower Silurian regional accumulation and Ordovician Black River-Trenton fields. Thermal maturity maps of the Devonian will better constrain burial history-petroleum generation models of the Utica Shale, as well as place limitations on the origin of regional oil and gas accumulations in Upper Devonian sandstone and Middle to Upper Devonian black shale.

  19. Bacteria-like bodies in coalified Carboniferous xylem - enigmatic microspheroids or possible evidence of microbial saprophytes in a vitrinite precursor

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, P.C. (US Geological Survey, Reston, VA (USA))


    Possible fossil cocci, both solitary and diplococcus types, have been discovered in coalified tissue (xylem) from coal balls and bituminous coal of Carboniferous age. Most of the presumed bacteria are microspheroids 1-2.5{mu}m in diameter and were found in partly degraded humic tissue (xylem) from a medullosan seed fern preserved in a coal ball (Herrin No. 6 coal bed, Westphalian D), an indication that they may have been saprotrophs (decay causing). The same kind of bodies were also found in coalified xylem from the Pittsburgh coal bed (early Stephanian). Whatever the origin of the bacteria-like bodies, they provide direct evidence of secondary organic components in tissue that gives rise to vitrinite and fusinite, major macerals of bituminous and anthracitic coals. 34 refs., 8 figs.

  20. Paracetamol sharpens reflection and spatial memory: a double-blind randomized controlled study in healthy volunteers

    Directory of Open Access Journals (Sweden)

    Pickering G


    Full Text Available Gisèle Pickering,1–3 Nicolas Macian,1,2 Claude Dubray,1–3 Bruno Pereira4 1University Hospital, CHU Clermont-Ferrand, Centre de Pharmacologie Clinique, 2Inserm, CIC 1405, UMR Neurodol 1107, 3Clermont Université, Laboratoire de Pharmacologie, Faculté de médecine, 4CHU de Clermont-Ferrand, Délégation Recherche Clinique Innovation, Clermont-Ferrand, France Background: Acetaminophen (APAP, paracetamol mechanism for analgesic and antipyretic outcomes has been largely addressed, but APAP action on cognitive function has not been studied in humans. Animal studies have suggested an improved cognitive performance but the link with analgesic and antipyretic modes of action is incomplete. This study aims at exploring cognitive tests in healthy volunteers in the context of antinociception and temperature regulation. A double-blind randomized controlled study (NCT01390467 was carried out from May 30, 2011 to July 12, 2011. Methods: Forty healthy volunteers were included and analyzed. Nociceptive thresholds, core temperature (body temperature, and a battery of cognitive tests were recorded before and after oral APAP (2 g or placebo: Information sampling task for predecisional processing, Stockings of Cambridge for spatial memory, reaction time, delayed matching of sample, and pattern recognition memory tests. Analysis of variance for repeated measures adapted to crossover design was performed and a two-tailed type I error was fixed at 5%. Results: APAP improved information sampling task (diminution of the number of errors, latency to open boxes, and increased number of opened boxes; all P<0.05. Spatial planning and working memory initial thinking time were decreased (P=0.04. All other tests were not modified by APAP. APAP had an antinociceptive effect (P<0.01 and body temperature did not change. Conclusion: This study shows for the first time that APAP sharpens decision making and planning strategy in healthy volunteers and that cognitive performance

  1. Change in Attachment Patterns and Reflective Function in a Randomized Control Trial of Transference-Focused Psychotherapy for Borderline Personality Disorder (United States)

    Levy, Kenneth N.; Meehan, Kevin B.; Kelly, Kristen M.; Reynoso, Joseph S.; Weber, Michal; Clarkin, John F.; Kernberg, Otto F.


    Changes in attachment organization and reflective function (RF) were assessed as putative mechanisms of change in 1 of 3 year-long psychotherapy treatments for patients with borderline personality disorder (BPD). Ninety patients reliably diagnosed with BPD were randomized to transference-focused psychotherapy (TFP), dialectical behavior…

  2. Eplerenone attenuates pulse wave reflection in chronic kidney disease stage 3-4--a randomized controlled study.

    Directory of Open Access Journals (Sweden)

    Lene Boesby

    Full Text Available Patients with chronic kidney disease (CKD have high cardiovascular mortality and morbidity associated with increased arterial stiffness. Plasma aldosterone levels are increased in CKD, and aldosterone has been found to increase vascular inflammation and fibrosis. It was hypothesized that aldosterone receptor inhibition with eplerenone could reduce arterial stiffness in CKD stage 3-4.The design was randomized, open, parallel group. Measurements of arterial stiffness markers were undertaken at weeks 1 and 24.24 weeks of add-on treatment with 25-50 mg eplerenone or standard medication.Primary outcome parameter was carotid-femoral pulse wave velocity (cfPWV. Secondary outcomes were augmentation index (AIx, ambulatory arterial stiffness index (AASI and urinary albumin excretion.Fifty-four CKD patients (mean eGFR 36 mL/min/1.73 m(2, SD 11 were randomized. Forty-six patients completed the trial. The mean difference in cfPWV changes between groups was 0.1 m/s (95%CI: -1.0, 1.3, P = 0.8. The mean difference in AIx changes between groups was 4.4% (0.1, 8.6, P = 0.04. AASI was unchanged in both groups. The ratio of change in urinary albumin excretion in the eplerenone group compared to the control was 0.61 (0.37, 1.01, P = 0.05. Four patients were withdrawn from the eplerenone group including three because of possible side effects; one was withdrawn from the control group. Mild hyperkalemia was seen on three occasions and was easily managed.The full planned number of patients was not attained. The duration of the trial may have been too short to obtain full effect of eplerenone on the arteries.Add-on treatment with eplerenone in CKD stage 3-4 did not significantly reduce cfPWV. There may be beneficial vascular effects leading to attenuated pulse wave reflection. Treatment was well-tolerated.ClinicalTrials.govNCT01100203.

  3. Application of integrated vitrinite reflectance and FAMM analyses for thermal maturity assessment of the northeastern Malay Basin, offshore Vietnam: Implications for petroleum prospectivity evaluation

    DEFF Research Database (Denmark)

    Petersen, H. I.; Sherwood, N.; Mathiesen, A.


    Several exploration wells have intersected a Cenozoic coal-bearing, fluvial-deltaic mudstone and sandstone succession in the northeastern Vietnamese part of the Malay Basin, and have successfully tested seismically identified direct hydrocarbon indicators (DHIs). The oil and gas/condensate discov...

  4. Scattering of electromagnetic waves from 3D multilayer random rough surfaces based on the second-order small perturbation method: energy conservation, reflectivity, and emissivity. (United States)

    Sanamzadeh, Mohammadreza; Tsang, Leung; Johnson, Joel T; Burkholder, Robert J; Tan, Shurun


    A theoretical investigation of energy conservation, reflectivity, and emissivity in the scattering of electromagnetic waves from 3D multilayer media with random rough interfaces using the second-order small perturbation method (SPM2) is presented. The approach is based on the extinction theorem and develops integral equations for surface fields in the spectral domain. Using the SPM2, we calculate the scattered and transmitted coherent fields and incoherent fields. Reflected and transmitted powers are then found in the form of 2D integrations over wavenumber in the spectral domain. In the integrand, there is a summation over the spectral densities of each of the rough interfaces with each weighted by a corresponding kernel function. We show in this paper that there exists a "strong" condition of energy conservation in that the kernel functions multiplying the spectral density of each interface obey energy conservation exactly. This means that energy is conserved independent of the roughness spectral densities of the rough surfaces. Results of this strong condition are illustrated numerically for up to 50 rough interfaces without requiring specification of surface roughness properties. Two examples are illustrated. One is a multilayer configuration having weak contrasts between adjacent layers, random layer thicknesses, and randomly generated permittivity profiles. The second example is a photonic crystal of periodically alternating permittivities of larger dielectric contrast. The methodology is applied to study the effect of roughness on the brightness temperatures of the Antarctic ice sheet, which is characterized by layers of ice with permittivity fluctuations in addition to random rough interfaces. The results show that the influence of roughness can significantly increase horizontally polarized thermal emission while leaving vertically polarized emissions relatively unaffected.

  5. Reflecting reflection in supervision

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    Reflection has moved from the margins to the mainstream in supervision. Notions of reflection have become well established since the late 1980s. These notions have provided useful framing devices to help conceptualize some important processes in guidance and counseling. However, some applications...... of reflection, rehabilitate them in order to capture broader connotations or move to new ways of regarding reflection that are more in keeping with not only reflective but also emotive, normative and formative views on supervision. The paper presents a critical perspective on supervision that challenge...

  6. The real world mental health needs of heart failure patients are not reflected by the depression randomized controlled trial evidence.

    Directory of Open Access Journals (Sweden)

    Phillip J Tully

    Full Text Available INTRODUCTION: International depression screening guidelines in heart failure (HF are partly based on depression treatment efficacy from randomized controlled trials (RCTs. Our aim was to test the external validity of depression RCT criteria in a sample of real-world HF patients. METHODS: HF patients admitted to 3 hospitals in South Australia were referred to a HF psychologist if not already receiving current psychiatric management by psychologist or psychiatrist elsewhere. Screening and referral protocol consisted of the following; (a. Patient Health Questionnaire ≥ 10; (b. Generalized Anxiety Disorder Questionnaire ≥ 7; (c. positive response to 1 item panic attack screener; (d. evidence of suicidality. Patients were evaluated against the most common RCT exclusion criteria personality disorder, high suicide risk, cognitive impairment, psychosis, alcohol or substance abuse or dependency, bi-polar depression. RESULTS: Total 81 HF patients were referred from 404 HF admissions, and 73 were assessed (age 60.6 ± 13.4, 47.9% female. Nearly half (47% met at least 1 RCT exclusion criterion, most commonly personality disorder (28.5%, alcohol/substance abuse (17.8% and high suicide risk (11.0%. RCT ineligibility criteria was more frequent among patients with major depression (76.5% vs. 46.2%, p<.01 and dysthymia (26.5% vs. 7.7%, p = .03 but not significantly associated with anxiety disorders. RCT ineligible patients reported greater severity of depression (M = 16.6 ± 5.0 vs. M = 12.9 ± 7.2, p = .02 and were higher consumers of HF psychotherapy services (M = 11.5 ± 4.7 vs. M = 8.5 ± 4.8, p = .01. CONCLUSION: In this real-world sample comparable in size to recent RCT intervention arms, patients with depression disorders presented with complex psychiatric needs including comorbid personality disorders, alcohol/substance use and suicide risk. These findings suggest external validity of depression screening and RCTs could serve as a basis for

  7. Long-wave infrared radiation reflected by compression stockings in the treatment of cellulite: a clinical double-blind, randomized and controlled study. (United States)

    Bagatin, E; Miot, H A; Soares, J L M; Sanudo, A; Afonso, J P J M; de Barros Junior, N; Talarico, S


    Cellulite refers to changes in skin relief on the thighs and buttocks of women, with a prevalence of 80-90%, causing dissatisfaction and search for treatment. Etiopathogenesis is multifactorial, as follows: herniation of the hypodermis towards the dermis, facilitated by perpendicular fibrous septa, changes in the dermal extracellular matrix, decreased adiponectin, genetic polymorphism, microcirculation alterations and inflammatory process. There are numerous therapeutic approaches, with little evidence of effectiveness. The long-wave infrared (LWIR) radiation interacts with water, improves microcirculation and stimulates metabolic processes. To date, the use of tissues with potential reflection of LWIR radiation has not been systematically investigated as adjuvant treatment for cellulite. To investigate the efficacy and safety of the treatment of cellulite through the use of compression stockings made with thread reflecting LWIR radiation. Clinical study of therapeutic intervention, controlled and double-blind, including 30 women, aging from 25 to 40 years, with cellulite of grades II and III on the thighs and buttocks who used compression stockings, "pantyhose" model, made with reflector thread of LWIR radiation, on only one randomized side. Women under other treatments for cellulite and with venous and/or blood insufficiencies were excluded. Evaluation of efficacy by clinical parameters, photographs, Dermatology Life Quality Index (DLQI), cutometry and high frequency ultrasonography and security by observation of adverse events and venous EcoDoppler recordings. DLQI scores showed significant reduction; the two-dimensional high-frequency ultrasonography showed an insignificant increase in dermal echogenicity as well as other efficacy parameters demonstrated no or slight improvement, with no differences between the sides exposed or not to LWIR; and there were no severe adverse events. Compression stockings, with or without thread reflector of LWIR, showed slight

  8. The reflective learning continuum: reflecting on reflection


    Peltier, J; Hay, A.; Drago, W


    The importance of reflection to marketing educators is increasingly recognized. However, there is a lack of empirical research which considers reflection within the context of both the marketing and general business education literature. This paper describes the use of an instrument which can be used to measure four identified levels of a reflection hierarchy: habitual action, understanding, reflection and intensive reflection and two conditions for reflection: instructor to student interacti...

  9. The interplay of self-reflection, social interaction and random events in the dynamics of opinion flow in two-party democracies (United States)

    Lichtenegger, Klaus; Hadzibeganovic, Tarik


    We propose a continuous process opinion formation model to study the dynamics of a multi-level relationship between voters, political parties, and facts in two-party democratic elections. In our model, opinions can take any real value between two extremes and an unaligned, moderate opinion state without a preference. Starting with a random opinion configuration, individual voter opinions evolve and change over time due to self-reflection, inter-personal communication, external media influence, and noise. Parties are influenced by their own ideologies, facts, and voters’ opinions. Elections are held periodically and the party that is closer in opinion to the majority of voters forms the new government. The government policy is then expected to be in proximity to the voter opinions and the policies of the currently ruling political party. We analyze the tension of opinions as a measure of how dramatically opinions can disagree within a given sample of voters and the success of the government and parties as the degree of coincidence between the policies and facts. Our model generates realistic quasi-periodic alternations between incumbents and challengers that are typical for two-party systems. Moreover, our model shows that relative to other voters’ strategies, conscious voting can lead to more successful governments of not only fact-oriented but also pragmatic and balanced political parties, irrespective of the strategies of the competing opposition parties. In addition, our simulations uncover several interesting features including less victories for strictly ideological or fact-oriented parties unless they include some aspects of populism or pragmatism. In this sense, our model can also describe situations where election outcomes are not necessarily based on votes for the current programs of competing parties and their placement on relevant issues, but instead result from voters’ dissatisfaction with the previous government and the votes against it.

  10. Beneficial effects on arterial stiffness and pulse-wave reflection of combined enalapril and candesartan in chronic kidney disease--a randomized trial.

    Directory of Open Access Journals (Sweden)

    Marie Frimodt-Møller

    Full Text Available Cardiovascular disease (CVD is highly prevalent in patients with chronic kidney disease (CKD. Inhibition of the renin-angiotensinsystem (RAS in hypertension causes differential effects on central and brachial blood pressure (BP, which has been translated into improved outcome. The objective was to examine if a more complete inhibition of RAS by combining an angiotensin converting enzyme inhibitor (ACEI and an angiotensin receptor antagonist (ARB compared to monotherapy has an additive effect on central BP and pulse-wave velocity (PWV, which are known markers of CVD.Sixty-seven CKD patients (mean GFR 30, range 13-59 ml/min/1.73 m(2 participated in an open randomized study of 16 weeks of monotherapy with either enalapril or candesartan followed by 8 weeks of dual blockade aiming at a total dose of 16 mg candesartan and 20 mg enalapril o.d. Pulse-wave measurements were performed at week 0, 8, 16 and 24 by the SphygmoCor device.Significant additive BP independent reductions were found after dual blockade in aortic PWV (-0.3 m/s, P<0.05 and in augmentation index (-2%, P<0.01 compared to monotherapy. Furthermore pulse pressure amplification was improved (P<0.05 and central systolic BP reduced (-6 mmHg, P<0.01.Dual blockade of the RAS resulted in an additive BP independent reduction in pulse-wave reflection and arterial stiffness compared to monotherapy in CKD patients.Clinical NCT00235287.

  11. Reflective Writing

    DEFF Research Database (Denmark)

    Ahrenkiel Jørgensen, Andriette


    a contribution to the discussions about the role of reflection in design work and in learning situations at large. By engaging with the dialogic reflection, which is one of the four essential types of reflection, (the three others being descriptive writing, descriptive reflection and critical reflection...

  12. Provenance of coals recovered from the wreck of HMAV Bounty

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, N.; Smith, A.H.V.; Crosdale, P.J. [Australian National Maritime Museum, Sydney, NSW (Australia)


    Coal samples from HMAV Bounty were analysed using standard techniques to shed light on their provenance. Petrographic analysis indicated they were Carboniferous, with high vitrinite and liptinite content and a mean random reflectance of vitrinite of 0.99%. Palynological analysis indicated the samples were derived from the Middle Coal Measures, Westphalian B. Combining coal rank (vitrinite reflectance), age, knowledge of seam distributions and coalfield history indicates the most like source to be the Durham Coalfield, possibly the Hutton or Low Main Seams. These coals were mined along the valley of the Wear in the latter part of the 18th century.

  13. Parent reflections of experiences of participating in a randomized controlled trial of a behavioral intervention for infants at risk of autism spectrum disorders. (United States)

    Freuler, Ashley C; Baranek, Grace T; Tashjian, Christene; Watson, Linda R; Crais, Elizabeth R; Turner-Brown, Lauren M


    Despite the mounting evidence of efficacy of early intervention for children with autism spectrum disorders, there is little research that considers the various perceptions and resources with which parents respond to the pressures and opportunities associated with participation in early intervention. Research is particularly lacking surrounding experiences of parents with infants who are at risk of autism spectrum disorders but do not (yet) have a diagnosed condition. This qualitative study aimed to explore the experiences of caregivers following their participation in a randomized controlled trial of Adapted Responsive Teaching, a parent-infant relationship-focused intervention for infants at risk of autism spectrum disorders in a community sample. Parents were randomized into either the treatment group, in which they participated in the Adapted Responsive Teaching intervention, or the community services group, in which they were provided with information regarding local early intervention services and were encouraged, but not required to, seek community services as part of their inclusion in the randomized controlled trial. Semistructured interviews were conducted with families following the completion of the randomized controlled trial. Participants consisted of 13 mothers and 4 fathers. Five dyads were interviewed together for a total of 14 families. Child ages ranged from 39 to 46 months at the time of interview. Analysis was conducted on 14 interviews from 10 families who were randomized into the treatment group and 4 families randomized into the community services group. Analysis was informed by a thematic analysis approach, which involved a systematic process of coding and theme identification both across and within groups. Themes that emerged across groups included Working against all odds, Value of the personal relationship, Getting the ball rolling, and Getting dad on board. One broad theme represented the data within the groups: Win-win (Adapted

  14. Quantifying Reflection

    DEFF Research Database (Denmark)

    Alcock, Gordon Lindsay


    This paper documents 1st semester student reflections on “learning to learn” in a team-based PBL environment with quantitative and qualitative student reflective feedback on the learning gains of 60 Architectural Technology and Construction Management students at VIA University College, Denmark....... It contrasts the students’ self-assessment in a range of ‘product’ skills such as Revit, Structural Design, Mathematics of construction, Technical Installations; as well as ‘process’ competencies such as ‘Working in a team’, Sharing knowledge, Maintaining a portfolio and Reflecting ON learning and FOR learning......´ These are all based on Blooms taxonomy and levels of competence and form a major part of individual student and group learning portfolios. Key Words :Project-Based learning, Reflective Portfolios, Self assessment, Defining learning gains, Developing learning strategies , Reflections on and for learning...

  15. Development and evaluation of an automated reflectance microscope system for the petrographic characterization of bituminous coals

    Energy Technology Data Exchange (ETDEWEB)

    Hoover, D. S.; Davis, A.


    The development of automated coal petrographic techniques will lessen the demands on skilled personnel to do routine work. This project is concerned with the development and successful testing of an instrument which will meet these needs. The fundamental differences in reflectance of the three primary maceral groups should enable their differentiation in an automated-reflectance frequency histogram (reflectogram). Consequently, reflected light photometry was chosen as the method for automating coal petrographic analysis. Three generations of an automated system (called Rapid Scan Versions I, II and III) were developed and evaluated for petrographic analysis. Their basic design was that of a reflected-light microscope photometer with an automatic stage, interfaced with a minicomputer. The hardware elements used in the Rapid Scan Version I limited the system's flexibility and presented problems with signal digitization and measurement precision. Rapid Scan Version II was designed to incorporate a new microscope photometer and computer system. A digital stepping stage was incorporated into the Rapid Scan Version III system. The precision of reflectance determination of this system was found to be +- 0.02 percent reflectance. The limiting factor in quantitative interpretation of Rapid Scan reflectograms is the resolution of reflectance populations of the individual maceral groups. Statistical testing indicated that reflectograms were highly reproducible, and a new computer program, PETAN, was written to interpret the curves for vitrinite reflectance parameters ad petrographic.

  16. Reflection ciphers

    DEFF Research Database (Denmark)

    Boura, Christina; Canteaut, Anne; Knudsen, Lars Ramkilde


    study the necessary properties for this coupling permutation. Special care has to be taken of some related-key distinguishers since, in the context of reflection ciphers, they may provide attacks in the single-key setting.We then derive some criteria for constructing secure reflection ciphers...... and analyze the security properties of different families of coupling permutations. Finally, we concentrate on the case of reflection block ciphers and, as an illustration, we provide concrete examples of key schedules corresponding to several coupling permutations, which lead to new variants of the block...

  17. Clinical linguistics: conversational reflections. (United States)

    Crystal, David


    This is a report of the main points I made in an informal "conversation" with Paul Fletcher and the audience at the 14th ICPLA conference in Cork. The observations arose randomly, as part of an unstructured 1-h Q&A, so they do not provide a systematic account of the subject, but simply reflect the issues which were raised by the conference participants during that time.

  18. Reflective Learning

    African Journals Online (AJOL)


    students who used learning log and those who did not especially for the course Pschopharmacology, but the mean scores did not show a significant difference for the course Psychology of Gender. The reflective reports of the students also roughly indicated that the students developed positive attitudes towards using ...


    Indian Academy of Sciences (India)

    IAS Admin

    Resonance journal of science education. April 2015 Volume 20 Number 4. GENERALARTICLES ... Development of. Probability Theory. K B Athreya. Classroom. Tutorial on Phyloge- netic Inference –1. Felix Bast. 360. 346. 286. PERSONAL REFLECTIONS. 368 The Road to IISc. M L Munjal (Transcribed by Maneesh Kunte).

  20. Random matrices

    CERN Document Server

    Mehta, Madan Lal


    Since the publication of Random Matrices (Academic Press, 1967) so many new results have emerged both in theory and in applications, that this edition is almost completely revised to reflect the developments. For example, the theory of matrices with quaternion elements was developed to compute certain multiple integrals, and the inverse scattering theory was used to derive asymptotic results. The discovery of Selberg's 1944 paper on a multiple integral also gave rise to hundreds of recent publications. This book presents a coherent and detailed analytical treatment of random matrices, leading

  1. On Reflection

    DEFF Research Database (Denmark)

    Blasco, Maribel


    This article explores how the concept of reflexivity is used in intercultural education. Reflexivity is often presented as a key learning goal in acquiring intercultural competence (ICC). Yet, reflexivity can be defined in different ways, and take different forms across time and space, depending...... on the concepts of selfhood that prevail and how notions of difference are constructed. First, I discuss how the dominant usages of reflexivity in intercultural education reflect and reproduce a Cartesian view of the self that shapes how ICC is conceptualized and taught. I discuss three assumptions that this view...... in designing learning objectives in intercultural education and in devising ways to attain them. Greater attention is also needed in intercultural education to the ways in which selfhood, and hence also reflexivity and constructions of difference, differ across space and time....

  2. Do writing and storytelling skill influence assessment of reflective ability in medical students' written reflections? (United States)

    Aronson, Louise; Niehaus, Brian; DeVries, Charlie D; Siegel, Jennifer R; O'Sullivan, Patricia S


    Increasingly, students are asked to write reflections as part of their medical education, but some question the influence of other factors on the evaluation of these reflections. In this pilot study, the investigators determined whether scores from a validated rubric to measure reflective ability were affected by irrelevant variance resulting from writing or storytelling ability. Students in clerkships wrote reflections on professionalism. All were given identical prompts, with half receiving additional structured guidelines on reflection. Sixty reflections, 30 from each group, were randomly chosen and scored for reflection, writing, and storytelling by trained raters using validated rubrics. There was no correlation between reflection and either writing (r = 0.049, P = .35) or storytelling (r = 0.14, P = .13). The guidelines increased reflection, but not writing or storytelling scores. Reflection is a distinct construct unaffected by learners' writing or storytelling skills. These findings support reflective ability as a distinct skill.

  3. A Reflective Look at Reflecting Teams (United States)

    Pender, Rebecca L.; Stinchfield, Tracy


    This article reviewed existing literature and research on the reflecting team process. There is a dearth of empirical research that explores the reflecting team process and the outcome of counseling that uses reflecting teams. Implications of using reflecting teams for counselors, counselor educators, and clients will be discussed. A call for…

  4. Challenging Narcissus, or Reflecting on Reflecting. (United States)

    Achilles, C. M.

    The concept of reflective practice and teaching people to be reflective practitioners is examined. The document begins with a look at professional knowledge according to three prominent professionals in the educational administration field: Schon, Schein, and Achilles. "Reflective" strategies that could be incorporated into courses and…

  5. The life in sight application study (LISA): design of a randomized controlled trial to assess the role of an assisted structured reflection on life events and ultimate life goals to improve quality of life of cancer patients

    NARCIS (Netherlands)

    Kruizinga, Renske; Scherer-Rath, Michael; Schilderman, Johannes B. A. M.; Sprangers, Mirjam A. G.; van Laarhoven, Hanneke W. M.


    It is widely recognized that spiritual care plays an important role in physical and psychosocial well-being of cancer patients, but there is little evidence based research on the effects of spiritual care. We will conduct a randomized controlled trial on spiritual care using a brief structured

  6. Randomization tests

    CERN Document Server

    Edgington, Eugene


    Statistical Tests That Do Not Require Random Sampling Randomization Tests Numerical Examples Randomization Tests and Nonrandom Samples The Prevalence of Nonrandom Samples in Experiments The Irrelevance of Random Samples for the Typical Experiment Generalizing from Nonrandom Samples Intelligibility Respect for the Validity of Randomization Tests Versatility Practicality Precursors of Randomization Tests Other Applications of Permutation Tests Questions and Exercises Notes References Randomized Experiments Unique Benefits of Experiments Experimentation without Mani

  7. Temperature-reflection I

    DEFF Research Database (Denmark)

    McGady, David A.


    -temperature path integrals for quantum field theories (QFTs) should be T-reflection invariant. Because multi-particle partition functions are equal to Euclidean path integrals for QFTs, we expect them to be T-reflection invariant. Single-particle partition functions though are often not invariant under T......In this paper, we revisit the claim that many partition functions are invariant under reflecting temperatures to negative values (T-reflection). The goal of this paper is to demarcate which partition functions should be invariant under T-reflection, and why. Our main claim is that finite...... that T-reflection is unrelated to time-reversal. Finally, we study the interplay between T-reflection and perturbation theory in the anharmonic harmonic oscillator in quantum mechanics and in Yang-Mills in four-dimensions. This is the first in a series of papers on temperature-reflections....

  8. Liberating Moral Reflection (United States)

    Horell, Harold D.


    The author argues that if we are to foster life-giving and liberating moral reflection, we must first liberate moral reflection from distortions; specifically, from the distorting effects of moral insensitivity, destructive moral relativism, and confusions resulting from a failure to understand the dynamics of moral reflection. The author proposes…

  9. Imaging Seismic Reflections

    NARCIS (Netherlands)

    op 't Root, T.J.P.M.; Op 't Root, Timotheus Johannes Petrus Maria


    The goal of reflection seismic imaging is making images of the Earth subsurface using surface measurements of reflected seismic waves. Besides the position and orientation of subsurface reflecting interfaces it is a challenge to recover the size or amplitude of the discontinuities. We investigate

  10. Intrasubject variability in power reflectance. (United States)

    Abur, Defne; Horton, Nicholas J; Voss, Susan E


    Power reflectance measurements are an active area of research related to the development of noninvasive middle-ear assessment methods. There are limited data related to test-retest measures of power reflectance. This study investigates test-retest features of power reflectance, including comparisons of intrasubject versus intersubject variability and how ear-canal measurement location affects measurements. Repeated measurements of power reflectance were made at about weekly intervals. The subjects returned for four to eight sessions. Measurements were made at three ear-canal locations: a deep insertion depth (with a foam plug flush at the entrance to the ear canal) and both 3 and 6 mm more lateral to this deep insertion. Repeated measurements on seven subjects are reported. All subjects were female, between 19 and 22 yr old, and enrolled at an undergraduate women's college. Measurements on both the right and left ears were made at three ear-canal locations during each of four to eight measurement sessions. Random-effects regression models were used for the analysis to account for repeated measures within subjects. The mean power reflectance for each position over all sessions was calculated for each subject. The comparison of power reflectance from the left and right ears of an individual subject varied greatly over the seven subjects; the difference between the power reflectance measured on the left and that measured on the right was compared at 248 frequencies, and depending on the subject, the percentage of tested frequencies for which the left and right ears differed significantly ranged from 10% to 93% (some with left values greater than right values and others with the opposite pattern). Although the individual subjects showed left-right differences, the overall population generally did not show significant differences between the left and right ears. The mean power reflectance for each measurement position over all sessions depended on the location of the

  11. Dissenting in Reflective Conversations

    DEFF Research Database (Denmark)

    Bjørn, Pernille; Boulus, Nina


    Reflective monitoring of research practices is essential. However, we often lack formal training in the practices of doing action research, and descriptions of actual inquiry practice are seldom included in publications. Our aim is to provide a glimpse of self-reflective practices based on our...... gradually evolved into second-person inquiry. We argue that enacting second-person reflective conversations renders alternative strategies for handling uncertainties through articulation of the tacit assumptions within particular empirical situations. Finally, we argue that reflective conversations should...... a methodological reflective approach that provides space for taking seriously uncertainties experienced in the field as these can be a catalyst for learning and sharpening our theoretical and empirical skills as action researchers. Through first-person inquiry, we investigate how our reflective conversations...

  12. Tandem resonator reflectance modulator (United States)

    Fritz, I.J.; Wendt, J.R.


    A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and light reflecting from the inner mirror is out of phase with light from the outer mirrors. 8 figs.

  13. Media for Reflection

    DEFF Research Database (Denmark)

    Knudsen, Morten


    This article develops the concept media for reflection in the interest of conceptualizing the interpretative frames that enable and limit reflection in management and leadership education. The concept ‘media for reflection’ allows us to conceptualize the social and cultural mediation of reflection...... of the mediations is analysed as well as the societal and organizational background. Furthermore, the means by which the two media enable and limit reflection in different ways is compared. Finally, the article discusses possible implications of the analysis in terms of management and leadership education....

  14. Reflective Lifeworld Research

    African Journals Online (AJOL)


    May 1, 2009 ... Reflective Lifeworld Research is a suitable title for a text that argues for, and gives convincing philosophical credence to, a qualitative sensibility in the human sciences. The key concept is 'reflective'. This is a rightful scientific attitude, the implications of which become the main theme of an academic.

  15. Earth's Reflection: Albedo (United States)

    Gillette, Brandon; Hamilton, Cheri


    When viewing objects of different colors, you might notice that some appear brighter than others. This is because light is reflected differently from various surfaces, depending on their physical properties. The word "albedo" is used to describe how reflective a surface is. The Earth-atmosphere has a combined albedo of about 30%, a number that is…

  16. Reflective Learning in Practice. (United States)

    Brockbank, Anne, Ed.; McGill, Ian, Ed.; Beech, Nic, Ed.

    This book contains 22 papers on reflective learning in practice. The following papers are included: "Our Purpose" (Ann Brockbank, Ian McGill, Nic Beech); "The Nature and Context of Learning" (Ann Brockbank, Ian McGill, Nic Beech); "Reflective Learning and Organizations" (Ann Brockbank, Ian McGill, Nic Beech);…

  17. Reflection: A Socratic approach (United States)

    Van Seggelen – Damen, Inge C. M.; Van Hezewijk, René; Helsdingen, Anne S.; Wopereis, Iwan G. J. H.


    Reflection is a fuzzy concept. In this article we reveal the paradoxes involved in studying the nature of reflection. Whereas some scholars emphasize its discursive nature, we go further and underline its resemblance to the self-biased dialogue Socrates had with the slave in Plato’s Meno. The individual and internal nature of the reflection process creates difficulty for studying it validly and reliably. We focus on methodological issues and use Hans Linschoten’s view of coupled systems to identify, analyze, and interpret empirical research on reflection. We argue that researchers and research participants can take on roles in several possible system couplings. Depending on who controls the manipulation of the stimulus, who controls the measuring instrument, who interprets the measurement and the response, different types of research questions can be answered. We conclude that reflection may be validly studied by combining different couplings of experimenter, manipulation, stimulus, participant, measurement, and response. PMID:29249867

  18. Self-Reflection

    DEFF Research Database (Denmark)

    Fausing, Bent


    and physical bodies are constantly broken with technology. Perception and reflection are in synergy. Reflection means etymologically to bend back, to mirror, and to think. My presentation will take its point of departure in this etymology and make perspectives to modern use of refection in digital media. I...... will take a look at the establishing of the modern self and possibilities of self-reflection, too. My examples will be from the so-called dark-selfies and from a new selfie form, which merge the present with the previous progressing into the future. I will discuss the media reflections as loos and/or gain....... As another but short viewpoint telepresence, Skype, will be discussed, where new screen types, presence and reflections are established. In a perspective, I debate my term sore-society in relation to my topic and especially the dark selfies....

  19. Reflectivity in Research Practice

    Directory of Open Access Journals (Sweden)

    Luigina Mortari


    Full Text Available The article grounds on the assumption that researchers, in order to be not mere technicians but competent practitioners of research, should be able to reflect in a deep way. That means they should reflect not only on the practical acts of research but also on the mental experience which constructs the meaning about practice. Reflection is a very important mental activity, both in private and professional life. Learning the practice of reflection is fundamental because it allows people to engage into a thoughtful relationship with the world-life and thus gain an awake stance about one’s lived experience. Reflection is a crucial cognitive practice in the research field. Reflexivity is largely practiced in qualitative research, where it is used to legitimate and validate research procedures. This study introduces different perspectives of analysis by focusing the discourse on the main philosophical approaches to reflection: pragmatistic, critical, hermeneutic, and finally phenomenological. The thesis of this study is that the phenomenological theory makes possible to analyze in depth the reflective activity and just by that to support an adequate process of training of the researcher.

  20. Enhancing the sensitivity of mesoscopic light reflection statistics in weakly disordered media by interface reflections

    CERN Document Server

    Park, Daniel J; Backman, Vadim


    Reflection statistics have not been well studied for optical random media whose mean refractive indices do not match with the refractive indices of their surrounding media. Here, we theoretically study how this refractive index mismatch between a one dimensional (1D) optical sample and its surrounding medium affects the reflection statistics in the weak disorder limit, when the fluctuation part of the refractive index (dn) is much smaller than the mismatch as well as the mean refractive index of the sample (dn ). In the theoretical derivation, we perform a detailed calculation that results in the analytical forms of mean and standard deviation (STD) of the reflectance in terms of disorder parameters (dn and lc) in an index mismatched backscattering system. Particularly, the orders of disorder parameters in STD of the reflectance for index mismatched systems is shown to be lower ( ( lc )^1/2 ) than that of the matched systems ( lc). By comparing STDs of the reflection coefficient of index matched and mismatche...

  1. Reflectance Reference Targets (OTTER) (United States)

    National Aeronautics and Space Administration — ABSTRACT: Spectral reflectance measurements of flat field targets as reference points representative of pseudo-invariant targets as measured by Spectron SE590...

  2. Reflectance Reference Targets (OTTER) (United States)

    National Aeronautics and Space Administration — Spectral reflectance measurements of flat field targets as reference points representative of pseudo-invariant targets as measured by Spectron SE590 spectrophotometer

  3. Thoughts on Reflection (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis


    Full Text Available There has been some acknowledgement in the published literature that reflection is a crucial element of the evidence based library and information practice (EBLIP model we have adopted (Booth 2004, 2006; Grant 2007; Helliwell 2007. As we work through a problem and try to incorporate the best available evidence into our decision making, reflection is required at several stages, including the very identification of the problem through to our assessment of the process itself and what we have learned in order to inform future practice. However, reflection and reflective writing have not fully been integrated into the process we espouse, and very little has been done to look more closely at this element of the model and how it can be integrated into professional learning.In a recently published research article, Sen (2010 confirms the relationship between reflection and several aspects of professional practice. These include critical review and decision making, two aspects that are tied closely to the evidence based process. Sen notes: Students were more likely to show evidence of learning, self‐development, the ability to review issues crucially, awareness of their own mental functions, ability to make decision [sic] and being empowered when they had mastered the art of reflective practice and the more deeply analytical reflective writing. (p.84 EBLIP (the journal tries to incorporate elements of reflection within the articles we publish. While we clearly believe in the need for our profession to do quality research and publish that research so that it can be accessible to practitioners, we also know that research cannot be looked at in isolation. Our evidence summaries are one way of reflecting critically on previously published research, and in the same vein, our classics bring older research studies back to the foreground. This work needs to continue to be discussed and looked at for its impact on our profession.More directly, the Using

  4. Creation, Identity and Reflection

    Directory of Open Access Journals (Sweden)

    Alina Beatrice Cheşcă


    Full Text Available The paper “Creation, Identity and Reflection” approaches the identification in the “mirror” of reality with creation, in other words seeking the authors’ identity in the reflected images. Reflection means attempting to find oneself, the mirror being the main principle of creation. Many characters become interesting only when they step into the world beyond the mirror, when their faces are doubled by the other self or when their selves are returned by other characters. The narcissistic concept of the mirror, i.e. the reflection in the mirror and the representation of the mirror itself, is a recurrent one in literature, but the reflection of the self which is not the self (as it is a reflection does not necessarily appear in a mirror or in a photograph or portrait. Sometimes, the not-self is returned to the self by another person or character. As far as Oscar Wilde’s theories are concerned, the main idea is that people are interesting for their masks, not for their inner nature. What Wilde calls “inner nature” is the characters’ un-reflected self and the mask is the reflection, the self in the mirror. Some characters’ relationships develop within a fiction that they dramatically try to preserve and protect with the risk of suffering. They refuse to take off the masks which define them in the others’ minds and hearts; the narcissistic individuals (both artists and characters seek and love their own image which they project upon facts, thus creating a fictive realm.

  5. The Reflective Foundation

    DEFF Research Database (Denmark)

    Lunde Jørgensen, Ida

    Private foundations and cultural philanthropy by élites is viewed with increasing skepticism in recent years, begging the question of the extent to which foundations reflect on their role vis a vis wider societal norms. Through the prism of the New Carlsberg Foundation, financed by the brewery...... Carlsberg A/S, the paper seeks to elucidate the way in which one culturally significant foundation from Denmark has reflected on - and legitimated - its work and investments at critical moments in the past decades. The paper indicates a foundation with a high degree of reflection on the wider societal...... pressures, and position as a mediator between culture and capital. The paper draws inspiration from the institutional logics perspective and Boltanski and Thévenot’s convention theoretical work, to analyse the legitimations pursued by the foundation....

  6. Reflections and Interpretations

    DEFF Research Database (Denmark)

    Reflections and Interpretations is an anthology on The Freedom Writers’ methodology. It is an anthology for all those with a professional need for texts explaining, not only how The Freedom Writers’ tools are being used, but also why they work so convincingly well. It is not an anthology of guide......Reflections and Interpretations is an anthology on The Freedom Writers’ methodology. It is an anthology for all those with a professional need for texts explaining, not only how The Freedom Writers’ tools are being used, but also why they work so convincingly well. It is not an anthology...

  7. Reflections on Leadership (United States)


    Reflections on Leadership ROBERT GATES Last year I read Partners in Command, a book by Mark Perry. It is an ac-count of the unique relationship...TITLE AND SUBTITLE Reflections on Leadership 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e...Long War, but the Long War is interested in us. How America’s military and civilian leadership grapples with these transcendent issues and dilemmas will

  8. Invisibility via reflecting coating


    Burdzy, Krzysztof; Kulczycki, Tadeusz


    We construct a subset $A$ of the unit disc with the following properties. (i) The set $A$ is the finite union of disjoint line segments. (ii) The shadow of $A$ is arbitrarily close to the shadow of the unit disc in "most" directions. (iii) If the line segments are considered to be mirrors reflecting light according to the classical law of specular reflection then most light rays hitting the set emerge on the other side of the disc moving along a parallel line and shifted by an arbitrarily sma...

  9. Postscript: Delving into Reflection

    Directory of Open Access Journals (Sweden)

    Susan Noffke


    Full Text Available Although, the authors presented an earlier version of the paper, "The Dimensions of Reflection: A Conceptual and Contextual Analysis", at the Annual Meeting of the American Educational Research Association, New Orleans, April, 1988, they did not have a chance to publish the paper till today. This postscript is about why the paper stayed as an “unpublished” conference paper for so long. Editors believe that the authors’ reflection on their academic journey with the paper in the postscript could be seen as an outstanding practical exemplar, a moral-political narrative of how to shape and create well-formed academic lives and identities.

  10. Self-Reflection

    DEFF Research Database (Denmark)

    Fausing, Bent


    Reflecting has a double meaning, mirroring and thinking. The seminar will investigate how these two meanings intervene in each other. As we perceive we are already in pre-refectory state, and thinking involves a lot of not only thoughts, but also of senses and sensing, wherefrom our thoughts star...

  11. Value reflected health education

    DEFF Research Database (Denmark)

    Wistoft, Karen; Nordentoft, Helle Merete


    This article examines the impact of a value-reflected approach in health education by demonstrating the nature of professional competence development connected to this approach. It is based on findings from two three-year health educational development projects carried out by school health nurses...... develop pedagogical competences in health education improving school childrens’ health....

  12. Reflection on Political Representation

    DEFF Research Database (Denmark)

    Kusche, Isabel


    This article compares how Members of Parliament in the United Kingdom and Ireland reflect on constituency service as an aspect of political representation. It differs from existing research on the constituency role of MPs in two regards. First, it approaches the question from a sociological...

  13. Reflections on Software Research

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 8. Reflections on Software Research. Dennis M Ritchie. Classics Volume 17 Issue 8 August 2012 pp 810-816. Fulltext. Click here to view fulltext PDF. Permanent link: Author Affiliations.

  14. Reflections on "La Esperanza" (United States)

    Cortez, Anita


    The author was recently asked to reflect on her "educational journey." As far as she can remember she has been hungry to learn. A friend once described her as having "hambres atrasadas," which he described as a kind of "hunger nipping at her heels." It goes back, of course, to her parents: Her father's and her early…

  15. Wave Reflection Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Larsen, Brian Juul

    The investigation concerns the design of a new internal breakwater in the main port of Ibiza. The objective of the model tests was in the first hand to optimize the cross section to make the wave reflection low enough to ensure that unacceptable wave agitation will not occur in the port. Secondly...... wave overtopping was studied as well....

  16. Teaching as Reflective Practice. (United States)

    Kennedy, Rosa L.; Wyrick, Amy M.

    This paper describes a method of reflective practice called "critical incident" which was used to examine teacher trainees' educational assumptions. A qualitative case study of one fifth-year teaching intern (Amy) at the University of Tennessee represents the experience of seven other master's level students already practicing within the…

  17. Reflectance Hashing for Material Recognition


    Zhang, Hang; Dana, Kristin; Nishino, Ko


    We introduce a novel method for using reflectance to identify materials. Reflectance offers a unique signature of the material but is challenging to measure and use for recognizing materials due to its high-dimensionality. In this work, one-shot reflectance is captured using a unique optical camera measuring {\\it reflectance disks} where the pixel coordinates correspond to surface viewing angles. The reflectance has class-specific stucture and angular gradients computed in this reflectance sp...

  18. Extracting infrared absolute reflectance from relative reflectance measurements. (United States)

    Berets, Susan L; Milosevic, Milan


    Absolute reflectance measurements are valuable to the optics industry for development of new materials and optical coatings. Yet, absolute reflectance measurements are notoriously difficult to make. In this paper, we investigate the feasibility of extracting the absolute reflectance from a relative reflectance measurement using a reference material with known refractive index.

  19. Reflecting differently. New dimensions: reflection-before-action and reflection-beyond-action

    Directory of Open Access Journals (Sweden)

    Sharon Edwards


    Full Text Available Background: This article attempts to move reflection forward from a process currently identified as two-dimensional (reflection-in-action and reflection-on-action to a four-dimensional process by adding reflection-before-action and reflection-beyond-action. In nursing clinical practice reflection-in-action is the required skill, but reflection-on-action is often advocated in nurse education through the application of reflective models in assignments. Nurse education draws on practice but generally, when using reflective practice, applies some sort of method or guide to direct student learning. This approach does not fully recognise that much learning arises from individual students’ own clinical practice experiences. The notion that undertaking reflection-on-action assignments develops the reflection-in-action skills needed for clinical practice is not demonstrated in the literature. Yet it is reflection-in-action that can aid professional practice and enhance learning. This is why it is important to explore a broader approach to reflection. Aims: To show more value can be gained from engaging with two additional dimensions of reflection – those of reflection-before-action and reflection-beyond-action, and to demonstrate how these can be linked to the better known concepts reflection-in-action and reflection-on-action, and to the author’s doctoral research, practice experience and practice development activities. Findings: Nursing reflection-on-action is widely used for a range of purposes, but restricting reflection in nurse education to this neglects the full potential of a broader application of reflection. A lifelong application of reflection can demonstrate its value for a more holistic and practical development approach. Conclusions: This article expands reflection and provides two additional dimensions. Instead of identifying reflection as two-dimensional, this article proposes that reflection can better serve learning from practice

  20. Variations in vitrinite reflectance values for the Upper Cretaceous Mesaverde Formation, southeastern Piceance basin, northwestern Colorado; implications for burial history and potential hydrocarbon generation. The Frying Pan Member of the Maroon Formation; a lower Permian( ) basin-margin dune field in northwestern Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Nuccio, V.F.; Johnson, R.C.; Johnson, S.Y.


    Most of the Upper Cretaceous Mesaverde Formation in the southeastern Piceance basin is thermally mature enough to have produced hydrocarbons by thermal generation, but only part of the Mesaverde is thermally mature enough to have expelled significant amounts of natural gas. The Early Permian( ) Frying pan Member of the Maroon Formation consists of quartz rich, very fine to fine-grained sandstone deposited in eolian dune and interdune environments. The Frying pan Member (formerly called the sandstone of the Frying pan River) is removed from the State Bridge Formation and assigned to the Maroon Formation.

  1. Landsat surface reflectance data (United States)



    Landsat satellite data have been produced, archived, and distributed by the U.S. Geological Survey since 1972. Users rely on these data for historical study of land surface change and require consistent radiometric data processed to the highest science standards. In support of the guidelines established through the Global Climate Observing System, the U.S. Geological Survey has embarked on production of higher-level Landsat data products to support land surface change studies. One such product is Landsat surface reflectance.

  2. Random thoughts (United States)

    ajansen; kwhitefoot; panteltje1; edprochak; sudhakar, the


    In reply to the news story “How to make a quantum random-number generator from a mobile phone” (16 May,, see also p5), which describes a way of delivering random numbers by counting the number of photons that impinge on each of the individual pixels in the camera of a Nokia N9 smartphone.

  3. Behavior of the reflection function of a plane-parallel medium for directions of incidence and reflection tending to horizontal directions


    Stam, J. W. Hovenier D. M.


    The atmospheres of (exo) planets and moons, as well as reflection nebulae, contain in general independently scattering particles in random orientation and are often supposed to be plane-parallel. Relations are presented for the (bidirectional) reflection function and several related functions of such a medium in case the directions of incidence and reflection both tend to horizontal directions. The results are quite general. The medium may be semi-infinite or finite, with or without a reflect...

  4. Reflections on the knife edge. (United States)

    Murphy, John Patrick Michael; Chabner, Bruce A


    The accompanying article, written by John Murphy, a retired lawyer and lifelong outdoorsman from his beloved Colorado Rockies, draws the striking parallel between his experiences as a mountain climber and as a patient with metastatic melanoma facing the hope and uncertainty of experimental therapy. Both are life-threatening circumstances, demanding courage and hope, and challenging our soul in a way almost unique to human experience. Both involve a conscious choice to move forward into dangerous and uncertain territory, and require a determination to look death (John's "Reaper") in the eye. Many remarkable books and films have been written about such experiences. I recall in particular the 2003 documentary film Touching the Void, about the incredible survival of a mountaineer who returned from a perilous fall in Peru. I highly recommend it to the reader. Another is Laura Hillenbrand's Unbroken: A World War II Story of Survival, Resilience, and Redemption (Random House, 2010), about the survival of a prisoner of war, the celebrated miler Louis Zamperini. Again, unbridled courage and undeniable hope turned futility into future. John Murphy's reflections remind us of the daily heroism of our patients who are holding tight to the lifeline offered by clinical research. Good climbing, John. All of us are with you on that Knife Edge, waiting for our turn to ascend... and hoping to be as courageous as you were then on Capitol Peak and are again now on the Knife Edge of a clinical trial. For our turn will come.

  5. Global South: Anthropological Reflections

    DEFF Research Database (Denmark)

    Steur, Luisa Johanna; Kalb, Don


    The global south is a complex and dynamic concept that straddles multiple social science and humanist disciplines. Emerging around 2000, it reflects the agenda of two ascending forces in those years: the antiglobalist (alterglobalist/global justice) movement and the World Social Forum, on the one...... hand, and an alliance of Southern states within the World Trade Organization on the other. Generally seen as an inheritor of the emancipatory thought behind the notion of the ‘third world,’ in the social sciences the idea of the ‘global south’ is also entangled with more classical academic themes...

  6. Universal randomness

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, Viktor S [Landau Institute for Theoretical Physics, Russian Academy of Sciences, Moscow (Russian Federation)


    In the last two decades, it has been established that a single universal probability distribution function, known as the Tracy-Widom (TW) distribution, in many cases provides a macroscopic-level description of the statistical properties of microscopically different systems, including both purely mathematical ones, such as increasing subsequences in random permutations, and quite physical ones, such as directed polymers in random media or polynuclear crystal growth. In the first part of this review, we use a number of models to examine this phenomenon at a simple qualitative level and then consider the exact solution for one-dimensional directed polymers in a random environment, showing that free energy fluctuations in such a system are described by the universal TW distribution. The second part provides detailed appendix material containing the necessary mathematical background for the first part. (reviews of topical problems)

  7. Matter reflects Antimatter

    CERN Document Server

    Bianconi, A.; Cristiano, A.; Leali, M.; Lodi Rizzini, E.; Venturelli, L.; Zurlo, N.


    It is common belief that the interaction between antimatter and ordinary solid matter is dominated by annihilation. However, non-destructive processes may play a relevant role too. One century ago E. Rutherford wrote about the "diffuse reflection" of alpha and beta particles by thin layers of different metals: "The observations ... of Geiger and Marsden on the scattering of alpha rays indicate that some of the alpha particles must suffer a deflexion of more than a right angle at a single encounter.... It will be shown that the main deductions from the theory are independent of whether the central charge is supposed to be positive or negative". Although the theory of electromagnetic scattering is in first approximation independent of the relative sign of the colliding particles, in the case where projectile antiprotons are shot against a wall of solid matter the Rutherford diffuse reflection mechanism competes with the annihilation process. So it is not obvious at all that a relevant part of an antiproton beam...

  8. Reflection on photographs. (United States)

    Brand, Gabrielle; McMurray, Anne


    Nursing students' exposure to clinical placements with older adults is instrumental in helping them adopt positive attitudes toward care of that population. This qualitative pilot study analyzed perceptions and expectations of a group of first-year students prior to a clinical placement with older adults. A photo-elicitation technique, involving viewing of realistic photographs of older adults being cared for, was used to help students clarify expectations. This was followed by thematic analysis of their perceptions and expectations. Analysis revealed five main themes: Dissecting What It Means to Be a Nurse, Revisioning Therapeutic Relationships in Terms of Dignity, Youthful Reflection on the Differences Between Young and Old, Feeling Challenged and Confronted, and Experiencing Sensitivity and Awkwardness Toward Older Adults' Nakedness. Engagement with images of older adults encouraged students to anticipate their clinical placement in an aged care setting in a more meaningful, reflective way than they may have done without prior exposure, suggesting a need for realistic pre-practice education. Copyright 2009, SLACK Incorporated.

  9. Fostering and evaluating reflective capacity in medical education: developing the REFLECT rubric for assessing reflective writing. (United States)

    Wald, Hedy S; Borkan, Jeffrey M; Taylor, Julie Scott; Anthony, David; Reis, Shmuel P


    Reflective writing (RW) curriculum initiatives to promote reflective capacity are proliferating within medical education. The authors developed a new evaluative tool that can be effectively applied to assess students' reflective levels and assist with the process of providing individualized written feedback to guide reflective capacity promotion. Following a comprehensive search and analysis of the literature, the authors developed an analytic rubric through repeated iterative cycles of development, including empiric testing and determination of interrater reliability, reevaluation and refinement, and redesign. Rubric iterations were applied in successive development phases to Warren Alpert Medical School of Brown University students' 2009 and 2010 RW narratives with determination of intraclass correlations (ICCs). The final rubric, the Reflection Evaluation for Learners' Enhanced Competencies Tool (REFLECT), consisted of four reflective capacity levels ranging from habitual action to critical reflection, with focused criteria for each level. The rubric also evaluated RW for transformative reflection and learning and confirmatory learning. ICC ranged from 0.376 to 0.748 for datasets and rater combinations and was 0.632 for the final REFLECT iteration analysis. The REFLECT is a rigorously developed, theory-informed analytic rubric, demonstrating adequate interrater reliability, face validity, feasibility, and acceptability. The REFLECT rubric is a reflective analysis innovation supporting development of a reflective clinician via formative assessment and enhanced crafting of faculty feedback to reflective narratives.

  10. Random triangles


    Matula, Dominik


    The author summarizes some previous results concerning random triangles. He describes the Gaussian triangle and random triangles whose vertices lie in a unit n-dimensional ball, in a rectangle or in a general bounded convex set. In the second part, the author deals with an inscribed triangle in a triangle - let ABC be an equilateral triangle and let M, N, O be three points, each laying on one side of the ABC. We call MNO inscribed triangle (in an equi- laterral triangle). The median triangle ...

  11. A comparison of two methods of teaching reflective ability in Year 3 medical students. (United States)

    Aronson, Louise; Niehaus, Brian; Hill-Sakurai, Laura; Lai, Cindy; O'Sullivan, Patricia S


    Little is known about best practices for teaching and learning reflection. We hypothesised that reflective ability scores on written reflections would be higher in students using critical reflection guidelines, or receiving feedback on reflective skill in addition to reflection content, or both, compared with those in students who received only a definition of reflection or feedback on reflection content alone. Using a 2 (guidelines) × 2 (feedback) × 2 (time) design, we randomly assigned half of our sample of 149 Year 3 medical students to receive critical reflection guidelines and the other half to receive only a definition of critical reflection. We then randomly divided both groups in half again so that one half of each group received feedback on both the content and reflective ability in their reflections, and the other received content feedback alone. The learners' performance was measured on the first and third written reflections of the academic year using a previously validated scoring rubric. We calculated descriptive statistics for the reflection scores and conducted a repeated-measures analysis of variance with two between-groups factors, guidelines and feedback, and one within-group factor, occasion, using the measure of reflective ability as the dependent variable. We failed to find a significant interaction between guidelines and feedback (F = 0.51, d.f. = 1, 145, p = 0.48). However, the provision of critical reflection guidelines improved reflective ability compared with the provision of a definition of critical reflection only (F = 147.1, d.f. = 1, 145, p teaching learners the characteristics of deeper, more effective reflection and helping them to acquire the skills they need to reflect well improves their reflective ability as measured by performance on reflective exercises. © Blackwell Publishing Ltd 2012.

  12. Teachers’ way of reflecting

    DEFF Research Database (Denmark)

    Lund, Lea


    of the Danish study was to investigate and understand teachers’ classroom experiences using Fenstermacher’s approach to develop a practical argument, as these classroom experiences are regarded as a potential source of learning for teachers. A three-level scale model from the study describes the teach-ers......’ reflections on practice. Based on this model, the paper provides a proposal regarding how to work with teachers’ professional development and learning processes. Educational implications and future research directions are discussed.......This paper contributes to insights on teachers’ thinking and practice by building partly on the large amount of prior research in the field of continuing professional development (in line with ISATT), and partly on examples from an empirical small-scale study executed in Denmark. The purpose...

  13. Reflections on conformal spectra

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyungrok; Kravchuk, Petr [Walter Burke Institute for Theoretical Physics, Caltech,Pasadena, California 91125 (United States); School of Natural Sciences, Institute for Advanced Study,Princeton, New Jersey 08540 (United States); Ooguri, Hirosi [Walter Burke Institute for Theoretical Physics, Caltech,Pasadena, California 91125 (United States); School of Natural Sciences, Institute for Advanced Study,Princeton, New Jersey 08540 (United States); Kavli Institute for the Physics and Mathematics of the Universe (WPI),University of Tokyo,Kashiwa 277-8583 (Japan)


    We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions Δ{sub 0} of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite Δ{sub 0} as well as for large Δ{sub 0}. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function.

  14. Reflecting Contemporary Design Research

    DEFF Research Database (Denmark)

    Engholm, Ida


    In recent years, design research has been the object of growing attention in universities and academies throughout the world. The present paper addresses the heterogeneous character of design research and the current need for reflection on the various approaches and interests. For this purpose......, the paper follows two steps. First, it proposes a categorization of the field in the form of a position model. The paper’s underlying assumption is that design research as a discipline exists in many different forms that cannot necessarily be brought together under one common academic research tradition......; instead it is necessary to attempt to define the field in order to initiate discussions about what constitutes the various research bases for design. Second, the paper discusses the implication for future design research when it is an interdisciplinary field that involves many disciplines, mindsets...

  15. Reflections on Conformal Spectra

    CERN Multimedia

    CERN. Geneva


    We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions Δ0 of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite Δ0 as well as for large Δ0. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function. (based on 1510.08772 with Kim & Ooguri). This seminar will be given via videolink

  16. Reflections on academic video

    Directory of Open Access Journals (Sweden)

    Thommy Eriksson


    Full Text Available As academics we study, research and teach audiovisual media, yet rarely disseminate and mediate through it. Today, developments in production technologies have enabled academic researchers to create videos and mediate audiovisually. In academia it is taken for granted that everyone can write a text. Is it now time to assume that everyone can make a video essay? Using the online journal of academic videos Audiovisual Thinking and the videos published in it as a case study, this article seeks to reflect on the emergence and legacy of academic audiovisual dissemination. Anchoring academic video and audiovisual dissemination of knowledge in two critical traditions, documentary theory and semiotics, we will argue that academic video is in fact already present in a variety of academic disciplines, and that academic audiovisual essays are bringing trends and developments that have long been part of academic discourse to their logical conclusion.

  17. Quantitative Hyperspectral Reflectance Imaging

    Directory of Open Access Journals (Sweden)

    Ted A.G. Steemers


    Full Text Available Hyperspectral imaging is a non-destructive optical analysis technique that can for instance be used to obtain information from cultural heritage objects unavailable with conventional colour or multi-spectral photography. This technique can be used to distinguish and recognize materials, to enhance the visibility of faint or obscured features, to detect signs of degradation and study the effect of environmental conditions on the object. We describe the basic concept, working principles, construction and performance of a laboratory instrument specifically developed for the analysis of historical documents. The instrument measures calibrated spectral reflectance images at 70 wavelengths ranging from 365 to 1100 nm (near-ultraviolet, visible and near-infrared. By using a wavelength tunable narrow-bandwidth light-source, the light energy used to illuminate the measured object is minimal, so that any light-induced degradation can be excluded. Basic analysis of the hyperspectral data includes a qualitative comparison of the spectral images and the extraction of quantitative data such as mean spectral reflectance curves and statistical information from user-defined regions-of-interest. More sophisticated mathematical feature extraction and classification techniques can be used to map areas on the document, where different types of ink had been applied or where one ink shows various degrees of degradation. The developed quantitative hyperspectral imager is currently in use by the Nationaal Archief (National Archives of The Netherlands to study degradation effects of artificial samples and original documents, exposed in their permanent exhibition area or stored in their deposit rooms.

  18. Bidirectional reflectance of zinc oxide (United States)

    Scott, R.


    This investigation was undertaken to determine original and useful information about the bidirection reflectance of zinc oxide. The bidirectional reflectance will be studied for the spectra between .25-2.5 microns and the hemisphere above the specimen. The following factors will be considered: (1) surface conditions; (2) specimen preparation; (3) specimen substrate, (4) polarization; (5) depolarization; (6) wavelength; and (7) angles of incident and reflection. The bidirectional reflectance will be checked by experimentally determined angular hemispherical measurements or hemispherical measurements will be used to obtain absolute bidirectional reflectance.

  19. Holographic reflector for reflective LCDs (United States)

    Sato, Atsushi; Murillo-Mora, Luis M.; Iwata, Fujio


    We describe a new holographic optical element to improve the image's quality of a reflective liquid crystal displays (LCDs). This new holographic reflector consists basically of 2 layers: a volume type transmission hologram layer and a metallic reflection layer. Compared with conventional reflectors for reflective LCDs, a high optical efficiency can be obtained because the hologram is able to concentrate the reflected light to the observer's eyes. Also, it avoids the problems of glare in the LCDs by deviating the reflected incident light (used for display) away from the direction of the direct reflection light. The transmission hologram's low wavelength selectivity permits us to obtain a near white color reflector for reflective LCDs which for multiple applications is the preferable color for the background.

  20. The Reflective Methodologists

    DEFF Research Database (Denmark)

    Kjær, Bjørg


    In recent years, a focus on inclusion and vulnerable children has reignited discussions about the quality of pedagogical work. It has also initiated processes of change that have challenged the Danish kindergarten tradition and the identity of the pedagogue in a number of different ways. In this ......In recent years, a focus on inclusion and vulnerable children has reignited discussions about the quality of pedagogical work. It has also initiated processes of change that have challenged the Danish kindergarten tradition and the identity of the pedagogue in a number of different ways...... in which the practical sense and tacit knowledge are related to questions of power and social actors’ strategies for positioning themselves within a social space. This demands a particular focus on the historical effect of the concept of ‘the reflective practitioner’ as a symbolic marker of identity...... in the cultural logic of the pedagogical field. I also address the way in which this logic considers practice to be the exponent of all that is good, meaningful and correct. My use of Schön’s concept also serves to illuminate that it has been a theoretical source of inspiration, which has undergone so many...

  1. Inference of dense spectral reflectance images from sparse reflectance measurement using non-linear regression modeling (United States)

    Deglint, Jason; Kazemzadeh, Farnoud; Wong, Alexander; Clausi, David A.


    One method to acquire multispectral images is to sequentially capture a series of images where each image contains information from a different bandwidth of light. Another method is to use a series of beamsplitters and dichroic filters to guide different bandwidths of light onto different cameras. However, these methods are very time consuming and expensive and perform poorly in dynamic scenes or when observing transient phenomena. An alternative strategy to capturing multispectral data is to infer this data using sparse spectral reflectance measurements captured using an imaging device with overlapping bandpass filters, such as a consumer digital camera using a Bayer filter pattern. Currently the only method of inferring dense reflectance spectra is the Wiener adaptive filter, which makes Gaussian assumptions about the data. However, these assumptions may not always hold true for all data. We propose a new technique to infer dense reflectance spectra from sparse spectral measurements through the use of a non-linear regression model. The non-linear regression model used in this technique is the random forest model, which is an ensemble of decision trees and trained via the spectral characterization of the optical imaging system and spectral data pair generation. This model is then evaluated by spectrally characterizing different patches on the Macbeth color chart, as well as by reconstructing inferred multispectral images. Results show that the proposed technique can produce inferred dense reflectance spectra that correlate well with the true dense reflectance spectra, which illustrates the merits of the technique.

  2. Random walks in a random environment

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. Random walks as well as diffusions in random media are considered. Methods are developed that allow one to establish large deviation results for both the 'quenched' and the 'averaged' case. Keywords. Large deviations; random walks in a random environment. 1. Introduction. A random walk on Zd is a stochastic ...

  3. Enabling honest reflection: a review. (United States)

    Gostelow, Naomi; Gishen, Faye


    Reflective practice provides a backbone to professionalism, a commitment to lifelong learning and competency-based education in the form of reflective portfolios. Changes in health care culture have promoted a move towards openness and reflection on challenging clinical encounters. Engagement with reflection has historically proved challenging to clinical educators. This Faculty Development Review examines this using a case study from the UK in which a postgraduate trainee was asked to disclose their reflective portfolio by a patient's legal representation. Critics have consequently questioned whether the educational benefit of reflection warrants these potential legal implications. In the context of pressure from accrediting bodies to demonstrate evidence of reflection, how can learners face this potential conflict of professional versus legal repercussions? We combine professional guidance from the UK and educational rationale from international settings to produce a guide for good practice. We offer guidance on facilitating reflection for learners in an open and honest way without diluting educationally effective critical reflection. Themes of anonymity, taking a balanced approach, seeking senior advice, focusing on learning outcomes and role-modelling are discussed. How can learners face this potential conflict of professional versus legal repercussions? Integrating reflection within the curriculum improves engagement and is key to experiential learning. Clinical educators should be aware of legal and professional guidance applicable to their own context. Both educators and learners should be aware that written reflection is an educational not a clinical tool, and so requires little or no patient-identifiable data, thereby ensuring safer reflective practice. © 2017 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  4. Random tensors

    CERN Document Server

    Gurau, Razvan


    Written by the creator of the modern theory of random tensors, this book is the first self-contained introductory text to this rapidly developing theory. Starting from notions familiar to the average researcher or PhD student in mathematical or theoretical physics, the book presents in detail the theory and its applications to physics. The recent detections of the Higgs boson at the LHC and gravitational waves at LIGO mark new milestones in Physics confirming long standing predictions of Quantum Field Theory and General Relativity. These two experimental results only reinforce today the need to find an underlying common framework of the two: the elusive theory of Quantum Gravity. Over the past thirty years, several alternatives have been proposed as theories of Quantum Gravity, chief among them String Theory. While these theories are yet to be tested experimentally, key lessons have already been learned. Whatever the theory of Quantum Gravity may be, it must incorporate random geometry in one form or another....

  5. Random functions and turbulence

    CERN Document Server

    Panchev, S


    International Series of Monographs in Natural Philosophy, Volume 32: Random Functions and Turbulence focuses on the use of random functions as mathematical methods. The manuscript first offers information on the elements of the theory of random functions. Topics include determination of statistical moments by characteristic functions; functional transformations of random variables; multidimensional random variables with spherical symmetry; and random variables and distribution functions. The book then discusses random processes and random fields, including stationarity and ergodicity of random

  6. Berlin Reflectance Spectral Library (BRSL) (United States)

    Henckel, D.; Arnold, G.; Kappel, D.; Moroz, L. V.; Markus, K.


    The Berlin Reflectance Spectral Library (BRSL) provides a collection of reflectance spectra between 0.3 and 17 µm. It was originally dedicated to support space missions to small solar system bodies. Meanwhile the library includes selections of biconical reflectance spectra for spectral data analysis of other planetary bodies as well. The library provides reference spectra of well-characterized terrestrial analogue materials and meteorites for interpretation of remote sensing reflectance spectra of planetary surfaces. We introduce the BRSL, summarize the data available, and access to use them for further relevant applications.

  7. Cultivating Reflective Practitioners in Technology Preparation: Constructing TPACK through Reflection

    Directory of Open Access Journals (Sweden)

    Liangyue Lu


    Full Text Available Teaching is a complex profession, which is further complicated by the integration of technology into classrooms. Reflection can help teachers unpack the complexity in their practice. Reflection can be an effective instructional strategy in helping preservice teachers develop technological pedagogical content knowledge (TPACK, the complex and dynamic knowledge necessary for effective technology integration into instruction. In this study, reflective activities were integrated into a Learning By Design (LBD environment, which was created to help preservice teachers develop TPACK. This paper investigated the participants’ TPACK development and examined how reflection helped them construct TPACK. Through content analysis of the participants’ reflective journals, the researcher found that the preservice teachers developed initial TPACK awareness. However, their reflection in technology knowledge and the content aspects of TPACK were limited and superficial. Interviews with the participants showed reflection helped the preservice teachers remember what they learned by describing and elaborating on their in-class experiences, pushed them to think about how to apply what they learned in their future classrooms, and helped them become more reflective and open-minded about using technology in classrooms. Finally, the researcher discussed this study’s implications for teacher educators and researchers.

  8. Cultivating Reflective Practitioners in Technology Preparation: Constructing TPACK through Reflection (United States)

    Lu, Liangyue


    Teaching is a complex profession, which is further complicated by the integration of technology into classrooms. Reflection can help teachers unpack the complexity in their practice. Reflection can be an effective instructional strategy in helping preservice teachers develop technological pedagogical content knowledge (TPACK), the complex and…

  9. Reflecting on the History, Ethics, and Application of Teacher Reflection. (United States)

    Hankes, Judith Elaine

    Three social factors are related to the evolution of the discourse on teacher reflection: the role of educational researchers and teacher educators; the social and economic crisis and its impact on education; and the shift from behaviorism to cognitivism. By relating the discourse of teacher change through reflection to these social factors, it…

  10. Postgraduate Education to Support Organisation Change: A Reflection on Reflection (United States)

    Stewart, Jim; Keegan, Anne; Stevens, Pam


    Purpose: This paper aims to explore how teaching and assessing reflective learning skills can support postgraduate practitioners studying organisational change and explores the challenges for tutors in assessing these journals. Design/methodology/approach: Assessment criteria were developed from the literature on reflective practice and…

  11. Studies of the Reflection, Refraction and Internal Reflection of Light (United States)

    Lanchester, P. C.


    An inexpensive apparatus and associated experiments are described for studying the basic laws of reflection and refraction of light at an air-glass interface, and multiple internal reflections within a glass block. In order to motivate students and encourage their active participation, a novel technique is described for determining the refractive…

  12. Audible reflection density for different late reflection criteria in rooms

    DEFF Research Database (Denmark)

    Krueger, Donata; Jeong, Cheol-Ho; Brunskog, Jonas


    For reasonably accurate but practical auralizations, some simplifications and approximations are needed. The main issue in the present investigation is that the reflection density of a room impulse response, in theory, increases so fast as a quadratic function of the elapsed time, even assuming...... only specular reflections. Therefore in this study, the upper threshold for audible reflection density is investigated for four different transition times of 25, 50, 75, and 100 ms through a headphone listening test. Binaural impulse responses and speech signals simulated in three rooms with different...... characteristics (an empty office, a lecture room, and an auditorium) are used as stimuli. Subjects are asked to increase/decrease the reflection density of a stimulus until they cannot distinguish it from the stimulus that follows the theoretical reflection density for the different transition times in the three...

  13. Ubuntu feminism: Tentative reflections

    Directory of Open Access Journals (Sweden)

    Drucilla Cornell


    Full Text Available The starting-point for the article is to provide a brief background on the Ubuntu Project that Prof. Drucilla Cornell convened in 2003; most notably the interviews conducted in Khayamandi, the support of a sewing collective, and the continued search to launch an Ubuntu Women�s Centre. The article will reflect on some of the philosophical underpinnings of ubuntu, whereafter debates in Western feminism will be revisited. Ubuntu feminism is suggested as a possible response to these types of feminisms. The authors support an understanding of ubuntu as critique and ubuntu feminism accordingly as a critical intervention that recalls a politics of refusal. The article ends by raising the importance of thinking about spatiality through ubuntu, and vice versa. It may seem strange to title an article Ubuntu feminism when feminism itself has often been identified as a European or Western idea. But, this article will argue that ubuntu offers conceptions of transindividuality and ways of social belonging that could respond in a meaningful way to some of European feminism�s own dilemmas and contradictions. Famously, one of the most intense debates in feminism was between those who defended an ethic of care in a relational view of the self, on one side, and those feminists who held on to more traditional conceptions of justice, placing an emphasis on individuality and autonomy, on the other side. The authors will suggest that ubuntu could address this tension in feminism. Thus, in this article the focus will not simply be on ubuntu, in order to recognise that there are other intellectual heritages worthy of consideration, other than those in Europe and the United States. It will also take a next step in arguing that ubuntu may be a better standpoint entirely from which to continue thinking about what it means to be a human being, as well as how to conceive of the integral interconnection human beings all have with one another. This connection through

  14. Flexible Bistable Cholesteric Reflective Displays (United States)

    Yang, Deng-Ke


    Cholesteric liquid crystals (ChLCs) exhibit two stable states at zero field condition-the reflecting planar state and the nonreflecting focal conic state. ChLCs are an excellent candidate for inexpensive and rugged electronic books and papers. This paper will review the display cell structure,materials and drive schemes for flexible bistable cholesteric (Ch) reflective displays.

  15. Ethical Reflections on Becoming Teachers (United States)

    Joseph, Pamela Bolotin


    This study analyzes narratives written in a culminating graduate seminar on reflective practice by 36 new secondary teachers who were asked to consider their moral beliefs, moral values and system of ethics as they reflected on their recent student teaching experiences. The findings explore how the participants depicted their constructed moral…

  16. Storytelling: A Guided Reflection Activity. (United States)

    Wheeler, Pamela L; Butell, Sue S; Epeneter, Beverly Jean; Langford, Cheryl Anne; Taylor, Jana Doughty


    Reflective practice is a mode of inquiry in the authors' baccalaureate nursing program. To increase students' ability to "think like a nurse," the Reflective Practice Storytelling Guide was developed to facilitate discussion during weekly clinical seminars in the students' final clinical course. To evaluate the effectiveness of this guided activity, students were asked to provide feedback to specific questions following each seminar when the reflective presence activity was utilized. Common themes emerged from the storytellers and the members of the group. Themes identified in the responses of the storytellers included role development and formation and the value of team support. Learning themes that emerged from the participants included communication, teamwork, clinical judgment, patient-centered care, use of resources, ethical and legal parameters in practice, and patient safety. Utilizing a guided reflection activity resulted in the students experiencing a broader, deeper understanding of reflective professional practice. Copyright 2016, SLACK Incorporated.

  17. [Concept analysis of reflective thinking]. (United States)

    Van Vuuren, M; Botes, A


    The nursing practice is described as a scientific practice, but also as a practice where caring is important. The purpose of nursing education is to provide competent nursing practitioners. This implies that future practitioners must have both critical analytical thinking abilities, as well as empathy and moral values. Reflective thinking could probably accommodate these thinking skills. It seems that the facilitation of reflective thinking skills is essential in nursing education. The research question that is relevant in this context is: "What is reflective thinking?" The purpose of this article is to report on the concept analysis of reflective thinking and in particular on the connotative meaning (critical attributes) thereof. The method used to perform the concept analysis is based on the original method of Wilson (1987) as described by Walker & Avant (1995). As part of the concept analysis the connotations (critical attributes) are identified, reduced and organized into three categories, namely pre-requisites, processes and outcomes. A model case is described which confirms the essential critical attributes of reflective thinking. Finally a theoretical definition of reflective thinking is derived and reads as follows: Reflective thinking is a cyclic, hierarchical and interactive construction process. It is initiated, extended and continued because of personal cognitive-affective interaction (individual dimension) as well as interaction with the social environment (social dimension). to realize reflective thinking, a level of internalization on the cognitive and affective domain is required. The result of reflective thinking is a integrated framework of knowledge (meaningful learning) and a internalized value system providing a new perspective on and better understanding of a problem. Reflective thinking further leads to more effective decision making- and problem solving skills.

  18. Synergies in Critical Reflective Practice and Science: Science as Reflection and Reflection as Science (United States)

    Mathieson, Luke


    The conceptions of reflective practice in education have their roots at least partly in the work of Dewey, who describes reflection as "the active, persistent, and careful consideration of any belief or supposed form of knowledge in the light of the grounds that support it and the further conclusions to which it tends" (Dewey 1933, p.9).…

  19. Random fixed points and random differential inclusions

    Directory of Open Access Journals (Sweden)

    Nikolaos S. Papageorgiou


    Full Text Available In this paper, first, we study random best approximations to random sets, using fixed point techniques, obtaining this way stochastic analogues of earlier deterministic results by Browder-Petryshyn, KyFan and Reich. Then we prove two fixed point theorems for random multifunctions with stochastic domain that satisfy certain tangential conditions. Finally we consider a random differential inclusion with upper semicontinuous orientor field and establish the existence of random solutions.

  20. Stochastic Gabor reflectivity and acoustic impedance inversion (United States)

    Hariri Naghadeh, Diako; Morley, Christopher Keith; Ferguson, Angus John


    To delineate subsurface lithology to estimate petrophysical properties of a reservoir, it is possible to use acoustic impedance (AI) which is the result of seismic inversion. To change amplitude to AI, removal of wavelet effects from the seismic signal in order to get a reflection series, and subsequently transforming those reflections to AI, is vital. To carry out seismic inversion correctly it is important to not assume that the seismic signal is stationary. However, all stationary deconvolution methods are designed following that assumption. To increase temporal resolution and interpretation ability, amplitude compensation and phase correction are inevitable. Those are pitfalls of stationary reflectivity inversion. Although stationary reflectivity inversion methods are trying to estimate reflectivity series, because of incorrect assumptions their estimations will not be correct, but may be useful. Trying to convert those reflection series to AI, also merging with the low frequency initial model, can help us. The aim of this study was to apply non-stationary deconvolution to eliminate time variant wavelet effects from the signal and to convert the estimated reflection series to the absolute AI by getting bias from well logs. To carry out this aim, stochastic Gabor inversion in the time domain was used. The Gabor transform derived the signal’s time–frequency analysis and estimated wavelet properties from different windows. Dealing with different time windows gave an ability to create a time-variant kernel matrix, which was used to remove matrix effects from seismic data. The result was a reflection series that does not follow the stationary assumption. The subsequent step was to convert those reflections to AI using well information. Synthetic and real data sets were used to show the ability of the introduced method. The results highlight that the time cost to get seismic inversion is negligible related to general Gabor inversion in the frequency domain. Also

  1. Ibuanyidanda (Complementary Reflection), Communalism and ...

    African Journals Online (AJOL)

    Fr. Prof. Asouzu

    Complementary Reflection, Communalism and Theory Formulation in African Philosophy 9. Ibuanyidanda (Complementary ...... Metaphysics,. Phenomenology and African Philosophy. Lagos: FADEC Publishers, pp.337-355. Van Steenberghen, Fernand. 1952. Ontology. Flynn, Martin J. trans. London: Joseph F. Wagner.

  2. Worldwide Marine Seismic Reflection Profiles (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC maintains a large volume of both Analog and Digital seismic reflection data. Currently only a limited number of lines are available online. Digital data include...

  3. Using a Written Journal Technique to Enhance Inquiry-Based Reflection about Teaching (United States)

    Fry, Jane; Carol, Klages; Venneman, Sandy


    The aim of this study was to explore the efficacy of two written journal techniques used to encourage teacher candidates' inquiry-based reflection regarding course textbook content. Ninety-six participants were randomly assigned to one of the two experimental conditions, journaling with Questions, Quotes and Reflections (Double Q R) or…

  4. Reflections

    Indian Academy of Sciences (India)

    human being - creativity and freedom - presupposing the existence of a human mind. His views, in turn, originate from his thinking about the nature of language which has been exercising his mind from the late. f0I1ies. Chomsky'S prominence as a socio-political thinker has completely overshadowed his professional status ...

  5. Reflections

    Indian Academy of Sciences (India)

    looking back, such a burst of creativity from a single mind in a single year is probably unparalled in our times. The 1905 volume of Annalen de, Physik stands to tell us that all this really happened. Ra;a,am Nityananda. Raman Research Institute, Bangalore 560 080, India. Why does this magnificent applied science, which ...

  6. Reflections

    Indian Academy of Sciences (India)

    Almost single handedly, he tackled all the administrative, infrastructural, and other daily nitty gritty problems of the whole department. From the very beginning, I devoted all my time to whatever work Prof Mitra assigned to me and my dedication came from a sense of gratitude to this great man for giving me an opportunity to ...

  7. Reflections

    Indian Academy of Sciences (India)


    Apr 1, 2004 ... climates, for example, those of Greenland, Iceland and the Faroe Islands on the one side and, on the other, the flora of the hot and arid African Sahara near Timbuctoo: regions where the struggle for existence is keenest and 'natural selection' of the hardiest forms takes place. Empetrum hermaphroditum, a ...

  8. Reflections

    Indian Academy of Sciences (India)

    senses - the tactile when we touch keys, the oral when we speak or listen, the visual when we read. Is it not possible that some day the path may be established more directly? We know that when the eye sees, all the consequent information is transmitted to the brain by means of electrical vibrations in the channel of the ...

  9. Reflections

    Indian Academy of Sciences (India)

    The following article by Norbert Wiener makes two points - the first explains the possibility of making computer programs 'human like' by building in learning and adaptfvity in them; the second cautions us on the danger that may arise due to the large difference in time constant between human thinking and action and ...

  10. Reflections

    Indian Academy of Sciences (India)

    (i) strong interactions (ii) electromagnetic interactions (iii) weak interactions (iv) gravitational interaction. As for the basic constituents, ... Further, the electromagnetic and the weak interactions are unified into a single force called the electroweak force. This is reminiscent ... immense problems facing India. It may be noted here ...


    African Journals Online (AJOL)

    Convention, humanitarian law, human rights and codes of conduct with emphasis on humanitarian assistance. Food aid as a development tool is questioned, and what will happen when food aid is drying out. The books provide a comprehensive analysis and are highly recommended. Key words: Food aia'; human security;.

  12. Reflections

    Indian Academy of Sciences (India)

    communication. However, the machine techniques of the present day have invaded the latter fields as well, so that the actual machine oftoday is very different from the image that. Butler held, and we cannot .... losing conflict to which his assumption of the best possible strategy on the part of his enemy would have doomed ...

  13. Reflections

    Indian Academy of Sciences (India)

    but tookno active part and made no speeches. I usually voted for a strike, and considered ..... L S Jacobsen, came to me from the Motor Division, and told me that in the engines of a certain type designed by his department the main ..... California with its warm climate and southern vegetation. We left Ann Arbor without regret.

  14. Reflections

    DEFF Research Database (Denmark)

    du Gay, Paul; Vikkelsø, Signe


    The notion of ‘change’ has become pervasive in contemporary organizational discourse. On the one hand, change is represented as an organizational imperative that increasingly appears to trump all other concerns. On the other hand, change is addressed as an abstract, generic entity that can be the...

  15. Reflections

    National Research Council Canada - National Science Library

    Jim Walsh


    ....) I imagine that valet parking will become very fashionable at upper end drinking establishments, and at blue collar shot-and-beer joints all across the rust belt, cars will be left idling in parking...

  16. Reflections (United States)

    Greiner, Walter


    This symposium was very special. It was topical: Some of the most outstanding problems in Nuclear Physics were discussed: Superheavy elements; extremely neutron rich elements, as well as nuclei with strangeness and their possible creation in the cosmos and on earth; the nuclear equation of state has to be identified within strongly compressed and hot nuclear matter as it appears in nucleus-nucleus encounters; giant nuclear systems which are short lived (˜ 10-19 - 10-20 seconds) and extremely important for identifying the vacuum decay in overcritical electric fields (this is a very fundamental process - the most fundamental one in Quantum Electrodynamics!); astrophysical centers of extreme high density around which magnificent sun-like objects are Kepler-orbiting are discovered in our Galaxy by R. Genzel and colleagues (these centers are no black holes those don't exist at all because repulsive gravitational forces may play an important role - the pseudocomplex general relativity eliminates the Schwarzschild singularity); network physics for distributing energy (nuclear, wind, sun, tides,...) all over Europe (and over the world) is basic for energy consumption now and even more so in future. We heard wonderful talks and I am grateful to all the friends and speakers (from Russia, America, Europe and India) for coming to Goa. It was a great symposium! Particular thanks go to Professor Bikash Sinha and especially to Professor Debades Bandyopadhyay from Calcutta who had the idea for and organized this Goa-symposium....

  17. Reflections

    Indian Academy of Sciences (India)

    The great Immanuel Kant, the philosopher of the. Enlightenment, set oot to explain why Galilean-Newtonian physics was so successful. At that time there were two contrasting philosophies concerning our knowledge of nature - the rationalist which believed that nature was subordinate to and had to obey reason; and.

  18. Reflections

    Indian Academy of Sciences (India)

    the environment. A very large part of the evolutionary progress, both biologically and culturally, has come from adversity. Life faces environments which are more often niggardly .... by teaching and learning, instead of by genes. The ability ... not even insure the survival of the population or the species when the environment.

  19. Random-phase metasurfaces at optical wavelengths

    DEFF Research Database (Denmark)

    Pors, Anders; Ding, Fei; Chen, Yiting


    of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light...

  20. Low reflectance radio frequency load (United States)

    Ives, R. Lawrence; Mizuhara, Yosuke M


    A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.

  1. Reflection of curved shock waves (United States)

    Mölder, S.


    Shock curvatures are related to pressure gradients, streamline curvatures and vorticity in flows with planar and axial symmetry. Explicit expressions, in an influence coefficient format, are used to relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. Using higher order, von Neumann-type, compatibility conditions, curved shock theory is applied to calculate the flow near singly and doubly curved shocks on curved surfaces, in regular shock reflection and in Mach reflection. Theoretical curved shock shapes are in good agreement with computational fluid dynamics calculations and experiment.

  2. Fragments on teachers' reflective practicum

    Directory of Open Access Journals (Sweden)

    Živković Predrag Ž.


    Full Text Available in many historical and comparative overviews of the works, in which there is an analytical discussion of the dominant pedagogical theories in the twentieth century, John Dewey (Dewey, 1933 is referred to as the founder and creator of the concept of reflection (reflective thought and knowledge in practice. Reflection as a concept is understood as the forms and the form of problem solving, as well as continuously thinking about the causes of problems in situations in situ, including active and systematically and consistently changing connecting ideas with solutions to the problems and situations that preceded them (Hatton & Smith, 1995. Reflective thinking is the most general level to tackle practical problems, allowing the ''recommended'' doubts and confusion before proposing possible solutions to the problem. Dewey wrote about a reflective action which refers to the use of solutions to the problem and to thinking through the course of the action. in later works of the authors who have dealt with this problem, an unambiguous link can be observed between the so-called ''professional'' action and the reflection on action which, in this cyclical relationship, leads to visible changes (Zeichner & Gore, 1984. Already at first glance, this implies a connection with experiential learning and adult position of observation and reflection in various models of experiential learning, which will be discussed later. it would be useful to compare this method with a cyclic action of routine as an expression of impulse, tradition and authority. Reflective action, as opposed to the routine, is a consistently and carefully thought-out action (practice reflection, which is an ''awakened'' knowledge and belief, and that is an expression of openness, accountability and commitment. We are ready for reflection, says Schon, when the ''knowledge-in-action'' - a kind of knowledge that professionals notice when it is acted spontaneously - occurs suddenly and unintentionally

  3. A Prospective Randomized Clinical Study of the Influence of Primary ...

    African Journals Online (AJOL)

    A Prospective Randomized Clinical Study of the Influence of Primary Closure or Dressing on. Post‑operative Morbidity after Mandibular Third. Molar Surgery. Peter E Egbor, Birch ... third molar surgery. Materials and Methods: This was a randomized clinical .... three sided buccal mucoperiosteal flap was made and reflected.

  4. Reflectance spectroscopy for soil analysis (United States)

    Over the last three decades or more, researchers have estimated soil properties using visible and near infrared (VNIR) diffuse reflectance spectroscopy (DRS), with varying results. This presentation reviews the history and state-of –the art of VNIR-DRS, including relative estimation accuracy for var...

  5. Critical Reflection as Doctoral Education (United States)

    Brookfield, Stephen D.


    This chapter considers how doctoral education, particularly in applied settings such as education, social work, counseling, and health care, could be reimagined if it was organized around the idea and process of critical reflection: of helping students to better understand how power operates in educational environments and how students' sense of…

  6. Trainee Teachers' Experience of Reflection (United States)

    McKenzie, Liz


    This article reports an investigation of trainee teachers' experience of reflection whilst undertaking a teaching qualification for the post-compulsory sector. The study used a sequential, mixed-methods design, employing a structured questionnaire and a semi-structured interview; 127 individuals completed the questionnaire about their experience…

  7. Planar Para Algebras, Reflection Positivity (United States)

    Jaffe, Arthur; Liu, Zhengwei


    We define a planar para algebra, which arises naturally from combining planar algebras with the idea of ZN para symmetry in physics. A subfactor planar para algebra is a Hilbert space representation of planar tangles with parafermionic defects that are invariant under para isotopy. For each ZN, we construct a family of subfactor planar para algebras that play the role of Temperley-Lieb-Jones planar algebras. The first example in this family is the parafermion planar para algebra (PAPPA). Based on this example, we introduce parafermion Pauli matrices, quaternion relations, and braided relations for parafermion algebras, which one can use in the study of quantum information. An important ingredient in planar para algebra theory is the string Fourier transform (SFT), which we use on the matrix algebra generated by the Pauli matrices. Two different reflections play an important role in the theory of planar para algebras. One is the adjoint operator; the other is the modular conjugation in Tomita-Takesaki theory. We use the latter one to define the double algebra and to introduce reflection positivity. We give a new and geometric proof of reflection positivity by relating the two reflections through the string Fourier transform.

  8. Creative reflection in industrial design

    NARCIS (Netherlands)

    Verbrugge, J.K.; Verbrugge, J.K.


    The dissertation is a reflection of the writer on his career as an industrial designer of Demand-Driven Design for a period of approximately 25 years. This period is exposed with a discussion of five designs. The projects are introduced by developments in the surrounding design landscape, such as


    NARCIS (Netherlands)

    Nelissen, J.M.C.; Tomic, W.


    The present article explores the theoretical underpinnings upon which Russian psychologists base their analysis of reflection. The intention is to arrive at a clearer understanding of their research aims and research methods, and to explore the relevance of their research to educational practice.

  10. Reykjanes ambient noise reflection interferometry

    NARCIS (Netherlands)

    Verdel, Arie; Wedemeijer, Harry; Paap, B; Vandeweijer, Vincent; Weemstra, C.; Jousset, Philippe; Franke, Steven; Blanck, Hanna; Águstsson, K.; Hersir, Gylfi Páll


    We present results from the application of ambient noise seismic interferometry (ANSI) to data that were recorded continuously in 2014 and 2015 at Iceland’s peninsula Reykjanes. The objective of this study is the retrieval of reflected body waves (P-waves) that provide high-resolution

  11. Vegetables, Coctails & Reflections / Marco Laimre

    Index Scriptorium Estoniae

    Laimre, Marko, 1968-


    Pealkirja "Vegetables, Coctails & Reflections" kandis Tallinna Kunstihoones 8.04.-28.05.2006 avatud Elin Kardi, Marko Mäetamme, Marco Laimre ja Andres Tali ühisnäitusel "Vägivald ja propaganda" Marco Laimre installatsioon. Marco Laimre esinemine raadiosaates "" Klassikaraadios 16.04.2006

  12. Reflections on the Gordon Commission (United States)

    Haertel, Edward


    Background:This brief reflection on the work of the Gordon Commission calls out significant themes and implications found in the various papers authored by the commissioners and other scholars, especially those included in this special issue of Teachers College Record. Purpose: The forward-looking vision of the Gordon Commission is contrasted with…

  13. Reflections on Community College Research (United States)

    Floyd, Deborah L.; Antczak, Laura


    Focused researchers have filled the important role of documenting the evolution of community colleges, which have changing missions and diverse programs, designed around their communities. This article reflects on key works of Council for the Study of Community College (CSCC) members in thematic areas of access, student success, faculty…

  14. Questioning Intuition through Reflective Engagement (United States)

    Schmidt, Christopher D.


    Current literature on ethics and moral development focuses on discussion concerning the impact of intuition on moral decision-making. Through the use of student journal reflections over the course of one semester, this study utilized a grounded theory approach in order to explore and understand participant levels of awareness and understanding of…




  16. Event detection using population-based health care databases in randomized clinical trials

    DEFF Research Database (Denmark)

    Thuesen, Leif; Jensen, Lisette Okkels; Tilsted, Hans Henrik


    To describe a new research tool, designed to reflect routine clinical practice and relying on population-based health care databases to detect clinical events in randomized clinical trials.......To describe a new research tool, designed to reflect routine clinical practice and relying on population-based health care databases to detect clinical events in randomized clinical trials....

  17. Random broadcast on random geometric graphs

    Energy Technology Data Exchange (ETDEWEB)

    Bradonjic, Milan [Los Alamos National Laboratory; Elsasser, Robert [UNIV OF PADERBORN; Friedrich, Tobias [ICSI/BERKELEY; Sauerwald, Tomas [ICSI/BERKELEY


    In this work, we consider the random broadcast time on random geometric graphs (RGGs). The classic random broadcast model, also known as push algorithm, is defined as: starting with one informed node, in each succeeding round every informed node chooses one of its neighbors uniformly at random and informs it. We consider the random broadcast time on RGGs, when with high probability: (i) RGG is connected, (ii) when there exists the giant component in RGG. We show that the random broadcast time is bounded by {Omicron}({radical} n + diam(component)), where diam(component) is a diameter of the entire graph, or the giant component, for the regimes (i), or (ii), respectively. In other words, for both regimes, we derive the broadcast time to be {Theta}(diam(G)), which is asymptotically optimal.

  18. RMSRo

    DEFF Research Database (Denmark)

    Nielsen, S.B.; Clausen, O.R.; McGregor, Eoin David


    of Geoscience, Høegh-Guldbergsgade 2, 8000 Aarhus C, Denmark Observed temperature, vitrinite reflectance and apatite fission tracks provide different but related information regarding temperature history. Their combined use in borehole heat flow determination as well as thermal and tectonic reconstruction...... requires a set of predictive models which are internally consistent. While the temperature- fission track system seems well-calibrated, several different vitrinite reflectance models exist. Although variability in vitrinite reflectance values is related to natural variations in the organic material such as......; initial composition, depositional environment, degree of oxygenation etc., the most important factor affecting the construction of vitrinite reflectance models is bias in the geological temperature history of the samples used for calibration. Here we add to the vitrinite reflectance calibration data set...

  19. Non-stationary random vibration analysis of structures under multiple correlated normal random excitations (United States)

    Li, Yanbin; Mulani, Sameer B.; Kapania, Rakesh K.; Fei, Qingguo; Wu, Shaoqing


    An algorithm that integrates Karhunen-Loeve expansion (KLE) and the finite element method (FEM) is proposed to perform non-stationary random vibration analysis of structures under excitations, represented by multiple random processes that are correlated in both time and spatial domains. In KLE, the auto-covariance functions of random excitations are discretized using orthogonal basis functions. The KLE for multiple correlated random excitations relies on expansions in terms of correlated sets of random variables reflecting the cross-covariance of the random processes. During the response calculations, the eigenfunctions of KLE used to represent excitations are applied as forcing functions to the structure. The proposed algorithm is applied to a 2DOF system, a 2D cantilever beam and a 3D aircraft wing under both stationary and non-stationary correlated random excitations. Two methods are adopted to obtain the structural responses: a) the modal method and b) the direct method. Both the methods provide the statistics of the dynamic response with sufficient accuracy. The structural responses under the same type of correlated random excitations are bounded by the response obtained by perfectly correlated and uncorrelated random excitations. The structural response increases with a decrease in the correlation length and with an increase in the correlation magnitude. The proposed methodology can be applied for the analysis of any complex structure under any type of random excitation.

  20. Ergodicity of Random Walks on Random DFA


    Balle, Borja


    Given a DFA we consider the random walk that starts at the initial state and at each time step moves to a new state by taking a random transition from the current state. This paper shows that for typical DFA this random walk induces an ergodic Markov chain. The notion of typical DFA is formalized by showing that ergodicity holds with high probability when a DFA is sampled uniformly at random from the set of all automata with a fixed number of states. We also show the same result applies to DF...

  1. Random fractional Fourier transform. (United States)

    Liu, Zhengjun; Liu, Shutian


    We propose a novel random fractional Fourier transform by randomizing the transform kernel function of the conventional fractional Fourier transform. The random fractional Fourier transform inherits the excellent mathematical properties from the fractional Fourier transform and can be easily implemented in optics. As a primary application the random fractional Fourier transform can be directly used in optical image encryption and decryption. The double phase encoding image encryption schemes can thus be modeled with cascaded random fractional Fourier transformers.

  2. Methodological Reflections: Inter- ethnic Research

    DEFF Research Database (Denmark)

    Singla, Rashmi


    This article reflects on the methodological and epistemological aspects of the ethical issues involved in encounters between researcher and research participants with ethnic minority background in contexts with diversity. Specific challenges involved in longitudinal research (10 - 15 years......) are also considered. The issues related to the social relevance of the research deriving from psycho political validity implying consideration of power dynamics in the personal, relational and collective domains are included. The primary basis for these reflections is a follow-up study concerning young...... adults’ life trajectories including ethnic minority and ethnic majority young adults (n= 9) in Denmark; the first wave conducted in the mid-nineties and the second wave 10 years later. In addition, some issues are taken up from a research project about youth intimate partnership formation patterns...

  3. Seismic reflection and refraction methods

    Digital Repository Service at National Institute of Oceanography (India)

    Chaubey, A.K.

    , reflection method is a very sophisticated version of the echosounding used in submarines, ships, and radar systems. Whereas, in seismic refraction method, principal portion of the wave-path is along the interface between the two layers and hence... into electrical signals, which are recorded digitally. The Ocean Bottom Seismometers 221 (OBS) are normally designed to record the earth motion under oceans and lakes from air-gun seismic sources. The air gun array is towed behind a ship usually at a...

  4. Evaluation of teaching: some reflections

    Directory of Open Access Journals (Sweden)

    Lourdes Canós Darós


    Full Text Available In this paper we present some reflections about the process of evaluation of teaching as a starting point for an improvement. Without information there cannot be change. Any improvement in the classroom requires dealing with information coming from, first, the students as counterpart in the university learning teaching process; second, other colleagues who give their professional opinion and; third, of ourselves as lecturers, so that a complete evaluation is made from all points of view.

  5. Supersymmetric quantum mechanics with reflections

    Energy Technology Data Exchange (ETDEWEB)

    Post, Sarah; Vinet, Luc [Centre de Recherches Mathematiques, Universite de Montreal, Montreal CP6128 (QC) H3C 3J7 (Canada); Zhedanov, Alexei, E-mail:, E-mail:, E-mail: [Donetsk Institute for Physics and Technology, Donetsk 83114 (Ukraine)


    We consider a realization of supersymmetric quantum mechanics where supercharges are differential-difference operators with reflections. A supersymmetric system with an extended Scarf I potential is presented and analyzed. Its eigenfunctions are given in terms of little -1 Jacobi polynomials which obey an eigenvalue equation of Dunkl type and arise as a q {yields} -1 limit of the little q-Jacobi polynomials. Intertwining operators connecting the wavefunctions of extended Scarf I potentials with different parameters are presented. (paper)

  6. Random walks in a random environment

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 114; Issue 4. Random Walks in a Random Environment. S R S Varadhan. Invited Articles Volume 114 Issue ... Author Affiliations. S R S Varadhan1. Department of Mathematics, Courant Institute of Mathematical Sciences, New York University, NY 10012, USA ...

  7. Reflection as the Homebase of Teacher Education

    Directory of Open Access Journals (Sweden)

    Andrias Tri Susanto


    Full Text Available Abstract Reflection is widely accepted as a process to support, or even underlie, teacher education. However, the concept holds several confusions among education experts and practitioners. This article would then attempt to explain some confusing terms by reviewing relevant literature on this issue and to provide discussions on the benefits and challenges of reflection manifested in various options of reflective practicum. Keywords: Reflection, teacher education, reflective practicum

  8. Random walks on random Koch curves

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, S; Hoffmann, K H [Institut fuer Physik, Technische Universitaet, D-09107 Chemnitz (Germany); Essex, C [Department of Applied Mathematics, University of Western Ontario, London, ON N6A 5B7 (Canada)


    Diffusion processes in porous materials are often modeled as random walks on fractals. In order to capture the randomness of the materials random fractals are employed, which no longer show the deterministic self-similarity of regular fractals. Finding a continuum differential equation describing the diffusion on such fractals has been a long-standing goal, and we address the question of whether the concepts developed for regular fractals are still applicable. We use the random Koch curve as a convenient example as it provides certain technical advantages by its separation of time and space features. While some of the concepts developed for regular fractals can be used unaltered, others have to be modified. Based on the concept of fibers, we introduce ensemble-averaged density functions which produce a differentiable estimate of probability explicitly and compare it to random walk data.

  9. Critical thinking evaluation in reflective writing: Development and testing of Carter Assessment of Critical Thinking in Midwifery (Reflection). (United States)

    Carter, Amanda G; Creedy, Debra K; Sidebotham, Mary


    develop and test a tool designed for use by academics to evaluate pre-registration midwifery students' critical thinking skills in reflective writing. a descriptive cohort design was used. a random sample (n = 100) of archived student reflective writings based on a clinical event or experience during 2014 and 2015. a staged model for tool development was used to develop a fifteen item scale involving item generation; mapping of draft items to critical thinking concepts and expert review to test content validity; inter-rater reliability testing; pilot testing of the tool on 100 reflective writings; and psychometric testing. Item scores were analysed for mean, range and standard deviation. Internal reliability, content and construct validity were assessed. expert review of the tool revealed a high content validity index score of 0.98. Using two independent raters to establish inter-rater reliability, good absolute agreement of 72% was achieved with a Kappa coefficient K = 0.43 (pwriting. Validation with large diverse samples is warranted. reflective practice is a key learning and teaching strategy in undergraduate Bachelor of Midwifery programmes and essential for safe, competent practice. There is the potential to enhance critical thinking development by assessingreflective writing with the CACTiM (reflection) tool to provide formative and summative feedback to students and inform teaching strategies. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  10. Reflections from the ivory tower. (United States)

    Capwell, Ellen M


    One health educator reflects on a career shift from public health practitioner to college faculty. The opportunity arose through informal Society for Public Health Education (SOPHE) networking. Similarities between the practitioner and academic roles are noted in relation to politics, mentoring, service on committees, presentations, consultation, and chain of command. Notable differences are discussed in areas of hiring and job security, work rules, teaching versus administration, molding students versus reshaping adults, degree of focus on health content versus program process, amount of bureaucracy and red tape, and degree of freedom to advocate. Recommendations are included for successful transitions. Both roles have unique rewards.

  11. SHORT COMMUNICATION: A useful reflection (United States)

    Douglas, R. J.; Steele, A. G.; Wood, B. M.; Hill, K. D.


    We discuss a simple, practical transformation between the probability density function (PDF) of the measurand and the associated PDF of the process for producing measurement results, both of which are used in metrology. This transformation is a reflection through the reported value and captures the essential reversal of skewness of these two perspectives for one-dimensional cases (i.e. any scalar quantity with no free parameters). It is useful for reconciling the skewness of the measurand and measurement-results perspectives, identifying cases where the choice of perspective should not matter and helping to treat the exceptional cases, involving PDF asymmetry, where it can matter.

  12. The digital divide: philosophical reflection

    Directory of Open Access Journals (Sweden)

    Dedyulina Marina Anatolevna


    Full Text Available The problem of digital divide itself is interesting for philosophical reflection as it lies at the crossroads of interests of social and political philosophy, philosophy of technology and epistemology, and these are just some of them. Due to the constant development of information technologies and the introduction of new technologies the digital divide is a dynamic problem. The main aim of this work is to analyse the conceptual and descriptive aspects of the problem of the digital divide, to get a more complete picture of the phenomenon. The digital divide is a complex problem that has social, political, cultural and ethical aspects.

  13. Reflections on strategic nurse leadership. (United States)

    White, Jean


    This paper sets out some personal reflections by the Chief Nursing Officer for Wales on the challenges facing nurses and midwives as they undertake strategic leadership roles in NHS organisations. The paper looks at the national approach taken in Wales where behavioural competencies for executive nurse directors have been implemented. It considers the implications of the breadth of responsibilities executive nurse directors have and the importance of developing and supporting middle grade nurse managers and clinical directors. It concludes by looking at who is responsible for care within an organisation. © 2012 Blackwell Publishing Ltd.

  14. Grapevine canopy reflectance and yield (United States)

    Minden, K. A.; Philipson, W. R.


    Field spectroradiometric and airborne multispectral scanner data were applied in a study of Concord grapevines. Spectroradiometric measurements of 18 experimental vines were collected on three dates during one growing season. Spectral reflectance, determined at 30 intervals from 0.4 to 1.1 microns, was correlated with vine yield, pruning weight, clusters/vine, and nitrogen input. One date of airborne multispectral scanner data (11 channels) was collected over commercial vineyards, and the average radiance values for eight vineyard sections were correlated with the corresponding average yields. Although some correlations were significant, they were inadequate for developing a reliable yield prediction model.

  15. Cosmological Reflection of Particle Symmetry

    Directory of Open Access Journals (Sweden)

    Maxim Khlopov


    Full Text Available The standard model involves particle symmetry and the mechanism of its breaking. Modern cosmology is based on inflationary models with baryosynthesis and dark matter/energy, which involves physics beyond the standard model. Studies of the physical basis of modern cosmology combine direct searches for new physics at accelerators with its indirect non-accelerator probes, in which cosmological consequences of particle models play an important role. The cosmological reflection of particle symmetry and the mechanisms of its breaking are the subject of the present review.

  16. An Algorithm for Successive Identification of Reflections

    DEFF Research Database (Denmark)

    Hansen, Kim Vejlby; Larsen, Jan


    A new algorithm for successive identification of seismic reflections is proposed. Generally, the algorithm can be viewed as a curve matching method for images with specific structure. However, in the paper, the algorithm works on seismic signals assembled to constitute an image in which...... the investigated reflections produce curves. In numerical examples, the authors work on signals assembled in CMP gathers. The key idea of the algorithm is to estimate the reflection curve parameters and the reflection coefficients along these curves by combining the multipulse technique and the generalized Radon...... stops the reflection estimation when the actual estimated reflection is insignificant. The reflection validation procedure ensures that the estimated reflections follow the shape of the investigated reflection curves. The algorithm is successfully used in two numerical examples. One is based...

  17. Managerial process: the reflective practitioner. (United States)

    Greenall, Paul


    The successful management journey is replete with moments of truth. Recognizing those moments and their significance for successful managerial practice is both a reflective and a conscious practice. This article, written by a successful pharmacist who now manages a busy public service hospital pharmacy documents his management journey from starting position as a drug store pharmacist to his present position in the public service. The paper uses managerial process theory as a critical tool to assess the author's own managerial style. Starting off as an autocratic manager with micro management tendencies, he has now developed a different style of management built on a basic philosophy about the value of people. He sees a need for managers to build a work environment that supports the efforts of employees. This style has not only made him a more effective people manager and motivator, but he argues it has also made him a better pharmacist. The author concludes by advocating the value of reflective practice, particularly for healthcare administrators as a means of balancing the technical demands of their disciplines with the ongoing requirements of managing people.

  18. Discharge lamp with reflective jacket

    Energy Technology Data Exchange (ETDEWEB)

    MacLennan, Donald A. (Gaithersburg, MD); Turner, Brian P. (Damascus, MD); Kipling, Kent (Gaithersburg, MD)


    A discharge lamp includes an envelope, a fill which emits light when excited disposed in the envelope, a source of excitation power coupled to the fill to excite the fill and cause the fill to emit light, and a reflector disposed around the envelope and defining an opening, the reflector being configured to reflect some of the light emitted by the fill back into the fill while allowing some light to exit through the opening. The reflector may be made from a material having a similar thermal index of expansion as compared to the envelope and which is closely spaced to the envelope. The envelope material may be quartz and the reflector material may be either silica or alumina. The reflector may be formed as a jacket having a rigid structure which does not adhere to the envelope. The lamp may further include an optical clement spaced from the envelope and configured to reflect an unwanted component of light which exited the envelope back into the envelope through the opening in the reflector. Light which can be beneficially recaptured includes selected wavelength regions, a selected polarization, and selected angular components.

  19. Random matrices, random processes and integrable systems

    CERN Document Server


    This book explores the remarkable connections between two domains that, a priori, seem unrelated: Random matrices (together with associated random processes) and integrable systems. The relations between random matrix models and the theory of classical integrable systems have long been studied. These appear mainly in the deformation theory, when parameters characterizing the measures or the domain of localization of the eigenvalues are varied. The resulting differential equations determining the partition function and correlation functions are, remarkably, of the same type as certain equations appearing in the theory of integrable systems. They may be analyzed effectively through methods based upon the Riemann-Hilbert problem of analytic function theory and by related approaches to the study of nonlinear asymptotics in the large N limit. Associated with studies of matrix models are certain stochastic processes, the "Dyson processes", and their continuum diffusion limits, which govern the spectrum in random ma...

  20. Robust reflective pupil slicing technology (United States)

    Meade, Jeffrey T.; Behr, Bradford B.; Cenko, Andrew T.; Hajian, Arsen R.


    Tornado Spectral Systems (TSS) has developed the High Throughput Virtual Slit (HTVSTM), robust all-reflective pupil slicing technology capable of replacing the slit in research-, commercial- and MIL-SPEC-grade spectrometer systems. In the simplest configuration, the HTVS allows optical designers to remove the lossy slit from pointsource spectrometers and widen the input slit of long-slit spectrometers, greatly increasing throughput without loss of spectral resolution or cross-dispersion information. The HTVS works by transferring etendue between image plane axes but operating in the pupil domain rather than at a focal plane. While useful for other technologies, this is especially relevant for spectroscopic applications by performing the same spectral narrowing as a slit without throwing away light on the slit aperture. HTVS can be implemented in all-reflective designs and only requires a small number of reflections for significant spectral resolution enhancement-HTVS systems can be efficiently implemented in most wavelength regions. The etendueshifting operation also provides smooth scaling with input spot/image size without requiring reconfiguration for different targets (such as different seeing disk diameters or different fiber core sizes). Like most slicing technologies, HTVS provides throughput increases of several times without resolution loss over equivalent slitbased designs. HTVS technology enables robust slit replacement in point-source spectrometer systems. By virtue of pupilspace operation this technology has several advantages over comparable image-space slicer technology, including the ability to adapt gracefully and linearly to changing source size and better vertical packing of the flux distribution. Additionally, this technology can be implemented with large slicing factors in both fast and slow beams and can easily scale from large, room-sized spectrometers through to small, telescope-mounted devices. Finally, this same technology is directly

  1. An investigation into the impact of reflective teaching on EFL learners autonomy and intrinsic motivation


    Elahe Fallah; Parisa Abdolrezapour


    This study has sought to explore the effect of reflective teaching on learner autonomy and the intrinsic motivation of Iranian upper-intermediate female learners. The subjects included 60 adult upper-intermediate EFL learners chosen out of ninety, based on the scores obtained through administration of the TOEFL exam. They were randomly assigned to two groups: a) the experimental group - taught by a reflective teacher - and b) the control group instructed by an unreflective teacher. The motiva...

  2. Misuse of randomization

    DEFF Research Database (Denmark)

    Liu, Jianping; Kjaergard, Lise Lotte; Gluud, Christian


    The quality of randomization of Chinese randomized trials on herbal medicines for hepatitis B was assessed. Search strategy and inclusion criteria were based on the published protocol. One hundred and seventy-six randomized clinical trials (RCTs) involving 20,452 patients with chronic hepatitis B....../150) of the studies were imbalanced at the 0.05 level of probability for the two treatments and 13.3% (20/150) imbalanced at the 0.01 level in the randomization. It is suggested that there may exist misunderstanding of the concept and the misuse of randomization based on the review....

  3. Reflectance spectra of primitive chondrites (United States)

    Trigo-Rodríguez, J. M.; Moyano-Cambero, C. E.; Llorca, J.


    We are studying a wide sample of pristine carbonaceous chondrites from the NASA Antarctic collection in order to get clues on the physico-chemical processes occurred in the parent bodies of these meteorites. We are obtaining laboratory reflectance spectra of different groups of carbonaceous chondrites, but here we focus in CM and CI chondrites. We discuss the main spectral features that can be used to identify primitive carbonaceous asteroids by remote sensing techniques. Two different spectrometers were used covering the entire 0.3 to 30 μm electromagnetic window. Only a handful of Near Earth Objects (NEOs) exhibit bands or features clearly associated with aqueous alteration. Among them are the target asteroids of Osiris Rex and Marco Polo-R missions.

  4. Reflections of a Freirean educator

    Directory of Open Access Journals (Sweden)

    Alfredo Manuel Ghiso


    Full Text Available It exposed a reflection on the role of education with meaning, where for to seek answers, it is good to work methodically with the students, spending more time to the critical analysis of our languages, our practices and especially our daily life. In this activity we would learn together to observe, compare, select and establish relationships between events and discourses; exercising the right to ask, disagree, criticize, be curious, creative open and democratic. It is certainly a challenge worth taking on, but it is impossible if we do not want it, if we do not restore the creative impulse that allows us to dream of a country where life has value and people have and can become subjects capable of exercising democratically their rights as citizens. All this requires educators high doses of creativity, energy, love, respect, dialogue and solidarity.

  5. Reflections in the clinical practice. (United States)

    Borrell-Carrió, F; Hernández-Clemente, J C


    The purpose of this article is to analyze some models of expert decision and their impact on the clinical practice. We have analyzed decision-making considering the cognitive aspects (explanatory models, perceptual skills, analysis of the variability of a phenomenon, creating habits and inertia of reasoning and declarative models based on criteria). We have added the importance of emotions in decision making within highly complex situations, such as those occurring within the clinical practice. The quality of the reflective act depends, among other factors, on the ability of metacognition (thinking about what we think). Finally, we propose an educational strategy based on having a task supervisor and rectification scenarios to improve the quality of medical decision making. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  6. Temporal reflectance changes in vegetables

    DEFF Research Database (Denmark)

    Dissing, Bjørn Skovlund; Clemmensen, Line Katrine Harder; Ersbøll, Bjarne Kjær


    in the surface chemistry of vegetables may be captured in an integrating sphere illumination which enables the creation of detailed surface chemistry maps with a good combination of spectral and spatial resolutions. Prior to multispectral image recording, the vegetables were prefried and frozen at -30Â......Quality control in the food industry is often performed by measuring various chemical compounds of the food involved. We propose an imaging concept for acquiring high quality multispectral images to evaluate changes of carrots and celeriac over a period of 14 days. Properties originating......°C for four months. During the 14 days of image recording, the vegetables were kept at +5°C in refrigeration. In this period, surface changes and thereby reflectance properties were very subtle. To describe this small variation we employed advanced statistical techniques to search a large featurespace...

  7. Endface reflectivities of optical nanowires. (United States)

    Wang, Shanshan; Hu, Zhifang; Yu, Huakang; Fang, Wei; Qiu, Min; Tong, Limin


    Endface reflectivities (ERs) of optical nanowires are investigated using three-dimensional finite-difference time-domain simulations. Typical ERs of both free-standing and substrate-supported silica, tellurite, PMMA and semiconductor nanowires or nanofibers are obtained. Unlike in conventional waveguides such as optical fibers, ERs of nanowires are usually considerably lower when operated in single mode. Dependences of ER on the diameter and the refractive index of the nanowire, and the wavelength of the guided light are also investigated. These results are helpful for estimating and understanding ERs in optical nanowires with diameters close to or smaller than the wavelengths of the light, and may offer valuable references for practical applications such as nanowire or nanofiber-based resonators and lasers.

  8. Gaussian Network’s Dynamics Reflected into Geometric Entropy

    Directory of Open Access Journals (Sweden)

    Domenico Felice


    Full Text Available We consider a geometric entropy as a measure of complexity for Gaussian networks, namely networks having Gaussian random variables sitting on vertices and their correlations as weighted links. We then show how the network dynamics described by the well-known Ornstein–Uhlenbeck process reflects into such a measure. We unveil a crossing of the entropy time behaviors between switching on and off links. Moreover, depending on the number of links switched on or off, the entropy time behavior can be non-monotonic.

  9. The role of emotion in design reflection

    NARCIS (Netherlands)

    Hammer, D.K.; Reymen, Isabelle


    Reflection on design processes performed by designers is called design reflection. In our view, this kind of reflection aims at answering essential questions like “Is my design answering the stakeholder concerns?”, “Am I solving the essential problems or am I wasting time on irrelevant aspects?”,

  10. Reflective Writing: Insights into What Lies beneath (United States)

    Kathpalia, Sujata S.; Heah, Carmel


    Educationists and writing practitioners consider reflection to be a defining feature of student portfolios (Fink 2003; Zubizarreta 2004; Jones and Shelton 2006). A writing portfolio without reflection is merely a collection of written work which does not contribute to "real" learning. Reflection in the portfolio approach happens when…

  11. Improving Inquiry Teaching through Reflection on Practice (United States)

    Lotter, Christine R.; Miller, Cory


    In this paper, we explore middle school science teachers' learning of inquiry-based instructional strategies through reflection on practice teaching sessions during a summer enrichment program with middle level students. The reflection sessions were part of a larger year-long inquiry professional development program in which teachers learned science content and inquiry pedagogy. The program included a 2-week summer institute in which teachers participated in science content sessions, practice teaching to middle level students, and small group-facilitated reflection sessions on their teaching. For this study, data collection focused on teachers' recorded dialogue during the facilitator - run reflection sessions, the teachers' daily written reflections, a final written reflection, and a written reflection on a videotaped teaching session. We investigated the teachers' reflection levels and the themes teachers focused on during their reflection sessions. Teachers were found to reflect at various reflection levels, from simple description to a more sophisticated focus on how to improve student learning. Recurrent themes point to the importance of providing situated learning environments, such as the practice teaching with immediate reflection for teachers to have time to practice new instructional strategies and gain insight from peers and science educators on how to handle student learning issues.

  12. Enabling Critical Reflection on Research Supervisory Practice (United States)

    Pearson, Margot; Kayrooz, Carole


    This paper describes the development of an instrument--The Reflective Supervisor Questionnaire (RSQ). The RSQ maps the domain of research supervisory practice as a facilitative process involving educational tasks and activities. It is designed to assist research supervisors explore, by means of self-reflection and reflection on feedback from…

  13. Reflective Journals: A Review of the Literature (United States)

    Lindroth, James T.


    The use of reflective journals has been identified as an effective tool to promote reflection in preservice teachers. This review of literature provides the reader with an understanding of the various ways journals are used and assessed in teacher education programs. The findings of this review outline the use of reflective journals on topics such…

  14. Reflection and Learning: Characteristics, Obstacles, and Implications (United States)

    Denton, David


    Reflection represents an important form of human thought; from ancient to modern times, the human capacity for reflective thinking has held the imagination of various philosophers and educational theorists. Despite this interest, researchers define reflection in different ways. One of the purposes of this article is to explore the activity of…

  15. Blocked Randomization with Randomly Selected Block Sizes

    Directory of Open Access Journals (Sweden)

    Jimmy Efird


    Full Text Available When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes.

  16. Blocked randomization with randomly selected block sizes. (United States)

    Efird, Jimmy


    When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes.

  17. Theory of reflection reflection and transmission of electromagnetic, particle and acoustic waves

    CERN Document Server

    Lekner, John


    This book deals with the reflection of electromagnetic and particle waves by interfaces. The interfaces can be sharp or diffuse. The topics of the book contain absorption, inverse problems, anisotropy, pulses and finite beams, rough surfaces, matrix methods, numerical methods,  reflection of particle waves and neutron reflection. Exact general results are presented, followed by long wave reflection, variational theory, reflection amplitude equations of the Riccati type, and reflection of short waves. The Second Edition of the Theory of Reflection is an updated and much enlarged revision of the 1987 monograph. There are new chapters on periodically stratified media, ellipsometry, chiral media, neutron reflection and reflection of acoustic waves. The chapter on anisotropy is much extended, with a complete treatment of the reflection and transmission properties of arbitrarily oriented uniaxial crystals. The book gives a systematic and unified treatment reflection and transmission of electromagnetic and particle...

  18. Daytime Water Detection Based on Sky Reflections (United States)

    Rankin, Arturo; Matthies, Larry; Bellutta, Paolo


    A water body s surface can be modeled as a horizontal mirror. Water detection based on sky reflections and color variation are complementary. A reflection coefficient model suggests sky reflections dominate the color of water at ranges > 12 meters. Water detection based on sky reflections: (1) geometrically locates the pixel in the sky that is reflecting on a candidate water pixel on the ground (2) predicts if the ground pixel is water based on color similarity and local terrain features. Water detection has been integrated on XUVs.

  19. Rapid seismic reflection imaging in an urban environment (United States)

    Liberty, L. M.


    Subsurface characterization in urban areas is important for city planners, municipalities, and engineers to estimate groundwater resources, track contaminants, assess earthquake or landslide hazards, and many other similar objectives. Improving geophysical imaging methods and results, while minimizing costs, provides greater opportunities for city/project planners and geophysicists alike to take advantage of the improved characterization afforded by the particular method. Seismic reflection results can provide hydrogeologic constraints for groundwater models, provide slip rate estimates for active faults, or simply map stratigraphy to provide target depth estimates. While many traditional urban seismic transects have included the use of vibroseis sources to improve reflection signals and attenuate cultural noise, low cost and high quality near-surface seismic reflection data can be obtained within an urban environment using impulsive sources at a variety of scales and at production rates that can significantly exceed those of swept sources. Sledgehammers and hydraulically powered accelerated weight drops allow rapid acquisition rates through dense urban corridors where the objective is to image targets in the upper one km depth range. In addition permit and land access issues; culturally noisy urban environments can provide additional challenges to producing high quality seismic reflection results. Acquisition methods designed to address both coherent and random noises include recording redundant, unstacked, unfiltered field records. Processing steps that improve data quality in this setting include diversity stacking to attenuate large-amplitude coherent (non-repeatable) vehicle noise and subtraction of power line signals via match filters to retain reflection signals near alternating current frequencies. These acquisition and processing approaches allow for rapid and low cost data acquisition at the expense of moderately increased computing time and disk space. I

  20. Random walks, random fields, and disordered systems

    CERN Document Server

    Černý, Jiří; Kotecký, Roman


    Focusing on the mathematics that lies at the intersection of probability theory, statistical physics, combinatorics and computer science, this volume collects together lecture notes on recent developments in the area. The common ground of these subjects is perhaps best described by the three terms in the title: Random Walks, Random Fields and Disordered Systems. The specific topics covered include a study of Branching Brownian Motion from the perspective of disordered (spin-glass) systems, a detailed analysis of weakly self-avoiding random walks in four spatial dimensions via methods of field theory and the renormalization group, a study of phase transitions in disordered discrete structures using a rigorous version of the cavity method, a survey of recent work on interacting polymers in the ballisticity regime and, finally, a treatise on two-dimensional loop-soup models and their connection to conformally invariant systems and the Gaussian Free Field. The notes are aimed at early graduate students with a mod...

  1. Reflectance measurement validation using acoustic horns. (United States)

    Rasetshwane, Daniel M; Neely, Stephen T


    Variability in wideband acoustic reflectance (and absorbance) measurements adversely affects the clinical utility of reflectance for diagnosis of middle-ear disorders. A reflectance standard would encourage consistency across different measurement systems and help identify calibration related issues. Theoretical equations exist for the reflectance of finite-length exponential, conical, and parabolic acoustic horns. Reflectance measurements were repeatedly made in each of these three horn shapes and the results were compared to the corresponding theoretical reflectance. A method is described of adjusting acoustic impedance measurements to compensate for spreading of the wave front that propagates from the small diameter sound port of the probe to the larger diameter of the acoustic cavity. Agreement between measured and theoretical reflectance was less than 1 dB at most frequencies in the range from 0.2 to 10 kHz. Pearson correlation coefficients were greater than 0.95 between measured and theoretical time-domain reflectance within the flare region of the horns. The agreement suggests that the distributed reflectance of acoustic horns may be useful for validating reflectance measurements made in human ear canals; however, refinements to reflectance measurement methods may still be needed.

  2. Remotely Sensing the Photochemical Reflectance Index (PRI) (United States)

    Vanderbilt, Vern


    In remote sensing, the Photochemical Reflectance Index (PRI) provides insight into physiological processes occurring inside the leaves in a stand of plants. Developed by Gamon et al., (1990 and 1992), PRI evolved from laboratory measurements of the reflectance of individual leaves (Bilger et al.,1989). Yet in a remotely sensed image, a pixel measurement may include light from both reflecting and transmitting leaves. We conducted laboratory experiments comparing values of PRI based upon polarized reflectance and transmittance measurements of water and nutrient stressed leaves. We illuminated single detached leaves using a current controlled light source (Oriel model 66881) and measured the leaf weight using an analytical balance (Mettler model AE 260) and the light reflected and transmitted by the leaf during dry down using two Analytical Spectral Devices spectroradiometers. Polarizers on the incident and reflected light beams allowed us to divide the leaf reflectance into two parts: a polarized surface reflectance and a non-polarized 'leaf interior' reflectance. Our results underscore the importance when calculating PRI of removing the leaf surface reflection, which contains no information about physiological processes ongoing in the leaf interior. The results show that the leaf physiology information is in the leaf interior reflectance, not the leaf transmittance. Applied to a plant stand, these results suggest use of polarization measurements in sun-view directions that minimize the number of sunlit transmitting leaves in the sensor field of view.

  3. Understanding the processes of writing papers reflectively. (United States)

    Regmi, Krishna; Naidoo, Jennie


    This paper explores the writing of research papers using reflective frameworks. Reflective practice is integral to professional education and development. However, healthcare students, academics and practitioners have given limited attention to how to write reflectively. In addition, there are limited resources on the practical aspects of writing papers reflectively. The following major databases were searched: PubMed, Medline, King's Library, Excerpta Medica Database, Department of Health database, Cumulative Index to Nursing and Allied Health Literature. The searches were conducted using 'free text' and 'index' terms. Only relevant papers published in English were reviewed and scrutinised. Unpublished reports, internal publications, snowballing from the reference lists and personal contacts were also included in the search. This is a review paper that critiques the frameworks used for reflective practice. Writing papers reflectively is a complex task. Healthcare professionals and researchers need to understand the meaning of reflection and make appropriate use of reflective frameworks. Demystifying the process of reflectively writing papers will help professionals develop skills and competencies. IMPLICATION FOR RESEARCH/PRACTICE: This article provides a practical guide to reflection and how nursing and allied healthcare students, academics and practitioners can practise it. The paper identifies four generic stages in frameworks: description, assessment, evaluation and action, which are illustrated by annotated 'skeletal' examples. It is hoped that this will assist the process of reflective practice, writing and learning.

  4. Perfect anti-reflection from first principles. (United States)

    Kim, Kyoung-Ho; Park, Q-Han


    Reducing unwanted reflections through impedance matching, called anti-reflection, has long been an important challenge in optics and electrical engineering. Beyond trial and error optimization, however, a systematic way to realize anti-reflection is still absent. Here, we report the discovery of an analytic solution to this long standing problem. For electromagnetic waves, we find the graded permittivity and permeability that completely remove any given impedance mismatch. We demonstrate that perfect broadband anti-reflection is possible when a dispersive, graded refractive index medium is used for the impedance-matching layer. We also present a design rule for the ultra-thin anti-reflection coating which we confirm experimentally by showing the anti-reflection behavior of an exemplary λ/25-thick coating made of metamaterials. This work opens a new path to anti-reflection applications in optoelectronic device, transmission line and stealth technologies.

  5. Reflections on the Goldwater Rule. (United States)

    Appelbaum, Paul S


    The APA's Goldwater Rule, precluding psychiatrists from rendering opinions to the media about public figures whom they have not examined, has often engendered controversy. Here, I consider the justifications for the rule, how well they stand up to criticism, and the extent, if any, to which modifications might be called for. Although embarrassment to the profession is often cited as the basis for the Rule, it reflects more substantive concerns, including the risk of harm to living persons and discouraging persons in need of treatment from seeking psychiatric attention. The most potent criticisms of the Rule are that it discourages public education about mental illness and its effects and precludes legitimate scholarly endeavors by psychiatrists studying foreign leaders, historical figures, and others. However, there are many ways of providing education about mental illness without violating the Rule, and read properly, it should not prevent legitimate historical investigation, though some clarification of the Rule on this point might be helpful. Even psychiatrists who seek to aid policymakers in dealing with international or domestic threats should not find that the Rule interferes with their efforts. On balance, the Goldwater Rule continues to be an important underpinning of ethical behavior by psychiatrists. © 2017 American Academy of Psychiatry and the Law.

  6. Reflecting on Normative Power Europe

    DEFF Research Database (Denmark)

    Manners, Ian James


    There is a widespread belief that the European Union (EU) is a novel kind of power not only in its own institutional set-up but also in its external relations. It is said to rely on civilian rather than military means and to pursue the spread of particular norms rather than self-interested geogra......There is a widespread belief that the European Union (EU) is a novel kind of power not only in its own institutional set-up but also in its external relations. It is said to rely on civilian rather than military means and to pursue the spread of particular norms rather than self......-interested geographical expansion or military superiority. In the 1970s, François Duchêne called it a ‘civilian power’ (1972: 43); in the early 2000s it was argued that the label ‘normative power’ would be better suited (Manners 2000, 2002). Just as Duchêne’s civilian power reflected the Cold War milieu of the 1970s......, the normative power approach signified a crystallisation of the EU in the post-Cold War era....

  7. Beyond Globalization: Reflections on Glocalism

    Directory of Open Access Journals (Sweden)

    Fred Dallmayr


    Full Text Available The old adage states that humankind moves “one step forward” before it moves “two steps backward”, suggesting that there is no such thing as a linear evolution. This is particularly true when applied to our present time, the “age of globalization”. In the case of globalism, “two steps back” are needed in order to assess more soberly the present historical trajectory, and capture the “internal dialectic” of globalism. In fact, what we are witnessing today in many parts of the world is a backlash to globalism, manifest in an upsurge of traditional nationalism, if not chauvinism and ethnocentrism. The core issue is a difficult relation between nearness and distance, between the concretely singular and the general/universal which the term “globalism” seeks to capture but, of course, cannot explain. My reflections in the following seek to explore and shed some light on this relation. In a first step, I venture into philosophical (and theological terrain in an effort to discern the meaning of human situatedness in a place, a space, or a “world”. Next, I discuss the inevitable tensions or conflicts between nearness and distance, that is, the inner “dialectic” between the local and the global. Finally, I translate the local/global syndrome into the correlation of “earth and world”, “roots and routes”, familiar loyalties and unfamiliar peregrinations.

  8. Quantum random number generators (United States)

    Herrero-Collantes, Miguel; Garcia-Escartin, Juan Carlos


    Random numbers are a fundamental resource in science and engineering with important applications in simulation and cryptography. The inherent randomness at the core of quantum mechanics makes quantum systems a perfect source of entropy. Quantum random number generation is one of the most mature quantum technologies with many alternative generation methods. This review discusses the different technologies in quantum random number generation from the early devices based on radioactive decay to the multiple ways to use the quantum states of light to gather entropy from a quantum origin. Randomness extraction and amplification and the notable possibility of generating trusted random numbers even with untrusted hardware using device-independent generation protocols are also discussed.

  9. Random Differential Privacy


    Hall, Rob; Rinaldo, Alessandro; Wasserman, Larry


    We propose a relaxed privacy definition called {\\em random differential privacy} (RDP). Differential privacy requires that adding any new observation to a database will have small effect on the output of the data-release procedure. Random differential privacy requires that adding a {\\em randomly drawn new observation} to a database will have small effect on the output. We show an analog of the composition property of differentially private procedures which applies to our new definition. We sh...

  10. Quantitative Raman spectroscopy in turbid matter: reflection or transmission mode? (United States)

    Oelkrug, Dieter; Ostertag, Edwin; Kessler, Rudolf W


    Raman intensities from reflection (X(R)) and transmission (X(T)) setups are compared by calculations based on random walk and analytical approaches with respect to sample thickness, absorption, and scattering. Experiments incorporating strongly scattering organic polymer layers and powder tablets of pharmaceutical ingredients validate the theoretical findings. For nonabsorbing layers, the Raman reflection and transmission intensities rise steadily with the layer thickness, starting for very thin layers with the ratio X(T)/X(R) = 1 and approaching for thick layers, a lower limit of X(T)/X(R) = 0.5. This result is completely different from the primary irradiation where the ratio of transmittance/reflectance decays hyperbolically with the layer thickness to zero. In absorbing materials, X R saturates at levels that depend strongly on the absorption and scattering coefficients. X T passes through a maximum and decreases then exponentially with increasing layer thickness to zero. From the calculated radial intensity spreads, it follows that quantitative transmission Raman spectroscopy requires diameters of the detected sample areas be about six times larger than the sample thickness. In stratified systems, Raman transmission allows deep probing even of small quantities in buried layers. In double layers, the information is independent from the side of the measurements. In triple layers simulating coated tablets, the information of X T originates mainly from the center of the bulk material whereas X R highlights the irradiated boundary region. However, if the stratified sample is measured in a Raman reflection setup in front of a white diffusely reflecting surface, it is possible to monitor the whole depth of a multiple scattering sample with equal statistical weight. This may be a favorable approach for inline Raman spectroscopy in process analytical technology.

  11. Designing a Reflective Teacher Education Course and Its Contribution to ELT Teachers' Reflectivity (United States)

    Tajik, Leila; Pakzad, Kazem


    Researchers in the present study planned a reflective teacher education course and documented the contribution of such a course to improving teachers' reflectivity. Five English teachers took part in the reflective teacher education course designed by the researchers. To record how the course could help improve reflective teaching, researchers…

  12. A Study on Reflection in In-Service Teacher Development: Introducing Reflective Practitioner Development Model (United States)

    Kayapinar, Ulas


    To date, studies on reflection seem to lack concern for in-service teacher development. This article proposes a new EFL reflective practitioner development model (RPDM) for an in-service program that is not only based on the principles of reflection, but that also measures teachers' reflective and self-efficacy development. Focusing on the…

  13. Reflective particle technology for identification of critical components

    Energy Technology Data Exchange (ETDEWEB)

    Tolk, K M


    Reflective Particle Tags were developed for uniquely identifying individual strategic weapons that would be counted in order to verify arms control treaties. These tags were designed to be secure from copying and transfer even after being lift under the control of a very determined adversary for a number of years. This paper discusses how this technology can be applied in other applications requiring confidence that a piece of equipment, such as a seal or a component of a secure, has not been replaced with a similar item. The hardware and software needed to implement this technology is discussed, and guidelines for the sign of systems that rely on these or similar randomly formed features for security applications are presented. Substitution of identical components is one of the easiest ways to defeat security seals, secure containers, verification instrumentation, and similar equipment. This technology, when properly applied, provides a method to counter this defeat scenario. This paper presents a method for uniquely identifying critical security related equipment. Guidelines for implementing identification systems based on reflective particles or similar random features without compromising their intrinsic security are discussed.

  14. Reflection Matrix Method for Controlling Light After Reflection From a Diffuse Scattering Surface (United States)



  15. Reflections on Quantum Data Hiding (United States)

    Winter, Andreas

    Quantum data hiding, originally invented as a limitation on local operations and classical communications (LOCC) in distinguishing globally orthogonal states, is actually a phenomenon arising generically in statistics whenever comparing a `strong' set of measurements (i.e., decision rules) with a `weak' one. The classical statistical analogue of this would be secret sharing, in which two perfectly distinguishable multi-partite hypotheses appear to be indistinguishable when accessing only a marginal. The quantum versions are richer in that for example LOCC allows for state tomography, so the states cannot be come perfectly indistinguishable but only nearly so, and hence the question is one of efficiency. I will discuss two concrete examples and associated sets of problems: 1. Gaussian operations and classical computation (GOCC): Not very surprisingly, GOCC cannot distinguish optimally even two coherent states of a single mode. Here we find states, each a mixture of multi-mode coherent states, which are almost perfectly distinguishable by suitable measurements, by when restricted to GOCC, i.e. linear optics and post-processing, the states appear almost identical. The construction is random and relies on coding arguments. Open questions include whether there one can give a constructive version of the argument, and whether for instance even thermal states can be used, or how efficient the hiding is. 2. Local operation and classical communication (LOCC): It is well-known that in a bipartite dxd-system, asymptotically logd bits can be hidden. Here we show for the first time, using the calculus of min-entropies, that this is asymptotically optimal. In fact, we get bounds on the data hiding capacity of any preparation system; these are however not always tight. While it is known that data hiding by separable states is possible (i.e. the state preparation can be done by LOCC), it is open whether the optimal information efficiency of (asymptotically) log d bits can be

  16. Digital Video/Multimedia Portfolios as a Tool To Develop Reflective Teacher Candidates. (United States)

    Spurgeon, Sheila; Bowen, James L.

    This research examined the effects of a process of digital video editing used to create multimedia portfolio has on the quality of teacher candidates' critical reflections. The target population was Northwestern Oklahoma State University teacher candidates. Subjects were 22 student teachers in the fall 2001. Subjects were randomly assigned to one…

  17. An Investigation into the Impact of Reflective Teaching on EFL Learners' Autonomy and Intrinsic Motivation (United States)

    Abdolrezapour, Parisa; Fallah, Elahe


    This study has sought to explore the effect of reflective teaching on learner autonomy and the intrinsic motivation of Iranian upper-intermediate female learners. The subjects included 60 adult upper-intermediate EFL learners chosen out of ninety, based on the scores obtained through administration of the TOEFL exam. They were randomly assigned to…

  18. Weblogs in Teacher Education Internships: Promoting Reflection and Self-Efficacy While Reducing Stress? (United States)

    Petko, Dominik; Egger, Nives; Cantieni, Andrea


    The study examines the use of weblogs in teacher education internships and its impact on student stress levels, self-efficacy, and reflective abilities. One hundred and seventy-six student teachers were randomly assigned to five groups. Four groups used weblogs (a) with emotion-focused or with problem-focused writing assignments in combination (b)…

  19. Supporting teachers' relationships with disruptive children: the potential of relationship-focused reflection

    NARCIS (Netherlands)

    Spilt, J.L.; Koomen, H.M.Y.; Thijs, J.T.; van der Leij, A.


    A relationship-focused reflection program (RFRP) was developed that targeted teachers' mental representations of relationships with specific children. Relative effectiveness was examined in a randomized comparative trial with repeated measures. Thirty-two teachers were assigned to the RFRP or the

  20. Tagclouds and Group Cognition: Effect of Tagging Support on Students' Reflective Learning in Team Blogs (United States)

    Xie, Ying; Lin, Shu-Yuan


    We investigated the effects of supported tagging (a prompting mechanism for students to stop and think about their writing) for team blogging on undergraduate students' reflective learning and the relationship between tagclouds and group cognition. Thirty-nine students were randomly assigned to six groups and blogged for 5 weeks. Three groups were…

  1. Random errors revisited

    DEFF Research Database (Denmark)

    Jacobsen, Finn


    the random errors of estimates of the sound intensity in, say, one-third octave bands from the power and cross power spectra of the signals from an intensity probe determined with a dual channel FFT analyser. This is not very practical, though. In this paper it is demonstrated that one can predict the random...

  2. a randomized controlled trial.

    African Journals Online (AJOL)

    milk, only an estimated one -fourth of neonates in India were breastfed within ... standard of care in India and mothers are informed about. 6 months of ... weeks postpartum. A random number sequence was generated using a com- puter program. Block randomization was used with a fixed block size of four. Concealment of ...

  3. Hashing, Randomness and Dictionaries

    DEFF Research Database (Denmark)

    Pagh, Rasmus

    time and memory space. To some extent we also consider lower bounds, i.e., we attempt to show limitations on how efficient algorithms are possible. A central theme in the thesis is randomness. Randomized algorithms play an important role, in particular through the key technique of hashing. Additionally...

  4. Random Walks and Trees

    Directory of Open Access Journals (Sweden)

    Shi Zhan


    Full Text Available These notes provide an elementary and self-contained introduction to branching random walks. Section 1 gives a brief overview of Galton–Watson trees, whereas Section 2 presents the classical law of large numbers for branching random walks. These two short sections are not exactly indispensable, but they introduce the idea of using size-biased trees, thus giving motivations and an avant-goût to the main part, Section 3, where branching random walks are studied from a deeper point of view, and are connected to the model of directed polymers on a tree. Tree-related random processes form a rich and exciting research subject. These notes cover only special topics. For a general account, we refer to the St-Flour lecture notes of Peres [47] and to the forthcoming book of Lyons and Peres [42], as well as to Duquesne and Le Gall [23] and Le Gall [37] for continuous random trees.

  5. Positive Stress and Reflective Practice Among Entrepreneurs

    Directory of Open Access Journals (Sweden)

    Kati Tikkamäki


    Full Text Available While heavy stress loads seem an unavoidable aspect of entrepreneurship, the positive side of stress (often referred to as ‘eustress’ remains a neglected area of research. This paper contributes to entrepreneurship research by linking the research streams of eustress and reflective practice. As a tool for analysing and developing thoughts and actions, reflective practice plays an important role in the interpretative work essential to positive stress experiences. Following an overview of approaches to stress at work, eustress and reflective practice, the paper explores how entrepreneurs experience the role of positive stress and reflective practice in their work and describes the reflective tools utilized by entrepreneurs in promoting eustress. The research process was designed to support reflective dialogue among the 21 Finnish entrepreneurs from different fields who participated in the study, with results based mainly on qualitative interviews. Nine of the interviewed entrepreneurs also kept a positive stress diary, including a three-day physiological measurement analysing their heartbeat variability. The findings suggest that positive stress and reflective practice are intertwined in the experiences of entrepreneurs and illustrate the role of reflective practice as a crucial toolset for promoting positive stress, comprising six reflective tools: studying oneself, changing one’s point of view, putting things into perspective, harnessing a feeling of trust, regulating resources and engaging in dialogue. Individual reflective capabilities vary, and a theory-driven division of reflective practice into individual, social and contextual dimensions is considered useful in understanding those differences. The research offers a starting point for exploring how eustress and reflective practice affect the well-being of entrepreneurs

  6. Reflective practice for personal and professional transformation. (United States)

    Kofoed, Nancy A


    Reflection is the mindful (and prayerful) consideration of professional or personal actions in such a way as to transform present and future experience. Nurses will find ways to create transformation in patient care through reflection in practice, clinical supervision, leadership, education, and evidence-based practice. This article discusses models and processes for reflective practice for professional, personal, and Christian spiritual transformation, making application to case studies in nursing practice.

  7. Autonomous Byte Stream Randomizer (United States)

    Paloulian, George K.; Woo, Simon S.; Chow, Edward T.


    Net-centric networking environments are often faced with limited resources and must utilize bandwidth as efficiently as possible. In networking environments that span wide areas, the data transmission has to be efficient without any redundant or exuberant metadata. The Autonomous Byte Stream Randomizer software provides an extra level of security on top of existing data encryption methods. Randomizing the data s byte stream adds an extra layer to existing data protection methods, thus making it harder for an attacker to decrypt protected data. Based on a generated crypto-graphically secure random seed, a random sequence of numbers is used to intelligently and efficiently swap the organization of bytes in data using the unbiased and memory-efficient in-place Fisher-Yates shuffle method. Swapping bytes and reorganizing the crucial structure of the byte data renders the data file unreadable and leaves the data in a deconstructed state. This deconstruction adds an extra level of security requiring the byte stream to be reconstructed with the random seed in order to be readable. Once the data byte stream has been randomized, the software enables the data to be distributed to N nodes in an environment. Each piece of the data in randomized and distributed form is a separate entity unreadable on its own right, but when combined with all N pieces, is able to be reconstructed back to one. Reconstruction requires possession of the key used for randomizing the bytes, leading to the generation of the same cryptographically secure random sequence of numbers used to randomize the data. This software is a cornerstone capability possessing the ability to generate the same cryptographically secure sequence on different machines and time intervals, thus allowing this software to be used more heavily in net-centric environments where data transfer bandwidth is limited.

  8. The Importance of Reflective Practice in Nursing

    Directory of Open Access Journals (Sweden)

    Lauren Caldwell


    Full Text Available Reflection is an essential attribute for the development of autonomous, critical, and advanced practitioners (Mantzoukas & Jasper, 2004. According to Chong (2009, “Reflective practice should be a continuous cycle in which experience and reflection on experiences are inter-related” (p. 112. Studies have shown that nurses who take the time to reflect on their daily experiences provide enhanced nursing care, have a better understanding of theiractions, which in return develops their professional skills (Hansebo & Kihlgren, 2001. Reflective practice is the ability to examine ones actions and experiences with the outcome of developing their practice and enhancing clinicalknowledge. Reflective practice affects all levels of nursing, from students, to advanced practice nursing students, aswell as practicing nurses. Reflective practice is an important component of the nursing curriculum. Research has shown the relationship between student nurses and their mentors is vital. In order for reflection to be effective open-mindedness, courage, and a willingness to accept, and act on, criticism must be present (Bulmam, Lathlean, & Gobbi, 2012. This paper will explore the current literature and implications related to reflective practice in nursing.

  9. Reflect: a practical approach to web semantics

    DEFF Research Database (Denmark)

    O'Donoghue, S.I.; Horn, Heiko; Pafilisa, E.


    To date, adding semantic capabilities to web content usually requires considerable server-side re-engineering, thus only a tiny fraction of all web content currently has semantic annotations. Recently, we announced Reflect (, a free service that takes a more practical approach......: Reflect uses augmented browsing to allow end-users to add systematic semantic annotations to any web-page in real-time, typically within seconds. In this paper we describe the tagging process in detail and show how further entity types can be added to Reflect; we also describe how publishers and content...

  10. Leaf Reflectances: Perkin-Elmer (OTTER) (United States)

    National Aeronautics and Space Administration — ABSTRACT: Absolute (diffuse & specular) reflectance of leaves measured in the lab by Perkin-Elmer spectrophotometer to aid in understanding remotely sensed...

  11. Layered magnets: polarized neutron reflection studies

    Energy Technology Data Exchange (ETDEWEB)

    Zabel, H.; Schreyer, A. [Ruhr-Univ. Bochum, Lehrstuhl fuer Experimentalphysik/Festkoerperphysik, Bochum (Germany)


    Neutron reflectivity measurements from extended surfaces, thin films and superlattices provide information on the chemical profile parallel to the film normal, including film thicknesses, average composition and interfacial roughness parameters. Reflectivity measurements with polarized neutrons are particularly powerful for analyzing the magnetic density profiles in thin films and superlattices in addition to chemical profiles. The basic theory of polarized neutron reflectivity is provided, followed by some examples and more recent applications concerning polarized neutron reflectivity studies from exchange coupled Fe/Cr superlattices. (author) 5 figs., 13 refs.

  12. The utility of reflective writing after a palliative care experience: can we assess medical students' professionalism? (United States)

    Braun, Ursula K; Gill, Anne C; Teal, Cayla R; Morrison, Laura J


    Medical education leaders have called for a curriculum that proactively teaches knowledge, skills, and attitudes required for professional practice and have identified professionalism as a competency domain for medical students. Exposure to palliative care (PC), an often deeply moving clinical experience, is an optimal trigger for rich student reflection, and students' reflective writings can be explored for professional attitudes. Our aim was to evaluate the merit of using student reflective writing about a PC clinical experience to teach and assess professionalism. After a PC patient visit, students wrote a brief reflective essay. We explored qualitatively if/how evidence of students' professionalism was reflected in their writing. Five essays were randomly chosen to develop a preliminary thematic structure, which then guided analysis of 30 additional, randomly chosen essays. Analysts coded transcripts independently, then collaboratively, developed thematic categories, and selected illustrative quotes for each theme and subtheme. Essays revealed content reflecting more rich information about students' progress toward achieving two professionalism competencies (demonstrating awareness of one's own perspectives and biases; demonstrating caring, compassion, empathy, and respect) than two others (displaying self-awareness of performance; recognizing and taking actions to correct deficiencies in one's own behavior, knowledge, and skill). Professional attitudes were evident in all essays. The essays had limited use for formal summative assessment of professionalism competencies. However, given the increasing presence of PC clinical experiences at medical schools nationwide, we believe this assessment strategy for professionalism has merit and deserves further investigation.

  13. Does learning to reflect make better modelers?

    NARCIS (Netherlands)

    Slinger, J.H.; Kwakkel, J.H.; Van der Niet, M.


    In this paper we address the role of reflective skills in the development and training of new System Dynamics modelers at the tertiary education level. Over the last two years students at the Delft University of Technology have written a reflective essay on their experiences with the


    The reflection of electromagnetic waves normally incident on the wavefronts of a semi-infinite standing sound wave is discussed. By analogy with the...with the sound frequency. An experiment is described in which the Bragg reflection of 3 cm electromagnetic waves from a standing sound wave beneath a water surface is observed.

  15. Specular Reflection from Rough Surfaces Revisited (United States)

    Yasuda, Kensei; Kim, Alvin; Cho, Hayley; Timofejev, Timofej; Walecki, Wojciech J.; Klep, James; Edelson, Amy S.; Walecki, Abigail S.; Walecki, Eve S.; Walecki, Peter S.


    In his beautiful paper, Hasan Fakhruddin reported observations of mirror-like reflections in the rough surface of a ground glass plate. Similar effects have been recently employed for metrology of the roughness of optical diffusers used in modern light emitting device illumination systems. We report the observations of specular reflection in…

  16. Stimulating reflection through engagement in social relationships

    NARCIS (Netherlands)

    Rajagopal, Kamakshi; Verjans, Steven; Van Bruggen, Jan; Sloep, Peter


    Rajagopal, K., Verjans, S., Van Bruggen, J., & Sloep, P. B. (2011). Stimulating reflection through engagement in social relationships. In W. Reinhardt, T. D. Ullmann, P. Scott, V. Pammer, O. Conlan, & A. J. Berlanga (Eds.), Proceedings of the 1st European Workshop on Awareness and Reflection in

  17. A descending hierarchy of reflection principles

    NARCIS (Netherlands)

    Visser, A.

    This paper can best be viewed as a portrait in miniature of a fascinating structure: a. descending hierarchy of reflection principles. Ascending hierarchies of reflection principles are amply studied, e.g. in Feferman's great paper Transfinite Recursive Progressions of Axiomatic

  18. Reflective Practice: Creating Capacities for School Improvement. (United States)

    Montie, Jo; York-Barr, Jennifer; Kronberg, Robi; Stevenson, Jane; Vallejo, Barb; Lunders, Cheri

    This monograph addresses the importance of and strategies for improving education through reflective practice, defined as cognitive processes and an open perspective that involve conscious self-examination in order to gain understandings and improve the lives of students. Chapter 1 provides an overview and explains origins of reflective practice…

  19. Recovering the Social Dimension of Reflection (United States)

    Connell, Martin Thomas


    Upon its publication in 1983, Schön's "The Reflective Practitioner" became almost instantly influential in the design of teacher education programs in North America. Within eight years of its publication, it was nearly impossible to find a teacher educator not emphasizing the importance of reflection (Erlandson, 2007; Zeichner &…

  20. Reflection and Perception in Professional Practice

    African Journals Online (AJOL)

    Christopher R Stones

    Reflection and Perception in Professional Practice by Peter Erlandson. Abstract. For the last decade, reflection has been a major theme in discussions about professional skillfulness and the development of the competence of practitioners such as nurses and teachers. The intellectual pattern that has structured ambitions in ...

  1. Reflective Practice in Group Co-Leadership (United States)

    Okech, Jane E. Atieno


    Group literature on co-leaders' experiences and perceptions while leading groups illuminate reflective practice as highly influential to co-leader relationships and performances. Using practical examples grounded by interdisciplinary literature on reflective practice, this article explores and expands dialogue on the complex interplay between…

  2. Lexical Concept Distribution Reflects Clinical Practice


    Breydo, Eugene; Shubina, Maria; Shalaby, James W.; Einbinder, Jonathan S.; Turchin, Alexander


    It is not known whether narrative medical text directly reflects clinical reality. We have tested the hypothesis that the pattern of distribution of lexical concept of medication intensification in narrative provider notes correlates with clinical practice as reflected in electronic medication records.

  3. Fairness and Using Reflective Journals in Assessment (United States)

    Clarkeburn, Henriikka; Kettula, Kirsi


    This study looks at the fairness of assessing learning journals both as the fairness in creating a valid and robust marking process as well as how different student groups may have unfair disadvantages in performing well in reflective assessment tasks. The fairness of a marking process is discussed through reflecting on the practical process and…

  4. Reflections on Teaching Financial Statement Analysis (United States)

    Entwistle, Gary


    In her 2011 article "Towards a 'scholarship of teaching and learning': The individual and the communal journey," Ursula Lucas calls for more critical reflection on individual teaching experiences and encourages sharing such experiences with the wider academy. In this spirit Gary Entwistle reflects upon his experiences teaching financial…

  5. Recommendations for Curricula That Stress Reflective Thinking. (United States)

    Wilkins, Dennis M.


    Offers a criticism of journalism as a professional practice of "doing" rather than "thinking," and suggests a higher standard through the notion of reflective judgment. Makes specific recommendations for curriculum additions to increase undergraduates' performance as critical thinkers and creators of reflective judgments that…

  6. Exploring Reflective Means to Handle Plagiarism (United States)

    Dalal, Nikunj


    Plagiarism has become widespread in the university teaching environment. This article presents practical wisdom from several years of experience handling plagiarism in two Information Systems (IS) courses with the exploratory use of reflective means such as dialogues and essays. There has been very little work on the use of reflective approaches…

  7. Teacher Reflective Practice in Jesuit High Schools (United States)

    Klug, Joseph H.


    Teachers who engage in reflective practice are more effective and may encourage higher student achievement. The purpose of this study is to explore and describe the methods that teachers use in order to engage in reflective practice. Further, it is essential to gain an understanding of how schools, including Jesuit high schools, promote reflective…

  8. Shared Reflections through Community-Based Theater. (United States)

    Salmons-Rue, Janet


    Describes the Community-Based Arts Project in central New York State, which offers a course through Cornell University that allows students to explore local history and family traditions through storytelling. The steps of story collecting and sharing are a circular transaction of reflecting, listening, telling, and reflecting with the audience,…

  9. Reflectance and Illumination Recovery in the Wild. (United States)

    Lombardi, Stephen; Nishino, Ko


    The appearance of an object in an image encodes invaluable information about that object and the surrounding scene. Inferring object reflectance and scene illumination from an image would help us decode this information: reflectance can reveal important properties about the materials composing an object; the illumination can tell us, for instance, whether the scene is indoors or outdoors. Recovering reflectance and illumination from a single image in the real world, however, is a difficult task. Real scenes illuminate objects from every visible direction and real objects vary greatly in reflectance behavior. In addition, the image formation process introduces ambiguities, like color constancy, that make reversing the process ill-posed. To address this problem, we propose a Bayesian framework for joint reflectance and illumination inference in the real world. We develop a reflectance model and priors that precisely capture the space of real-world object reflectance and a flexible illumination model that can represent real-world illumination with priors that combat the deleterious effects of image formation. We analyze the performance of our approach on a set of synthetic data and demonstrate results on real-world scenes. These contributions enable reliable reflectance and illumination inference in the real world.

  10. Promoting Inquiry through Science Reflective Journal Writing (United States)

    Towndrow, Phillip Alexander; Ling, Tan Aik; Venthan, A. M.


    The purpose of this research paper is to detail how reflective journal writing can be used to facilitate science students' curiosity and engagement in laboratory work. This study advocates reflective journal writing as an instructional tool and a student-created learning resource that can serve additional formative assessment purposes. The…

  11. Teaching Critical Reflection to Graduate Students (United States)

    Watson, Gavan Peter Longley; Kenny, Natasha


    Critical reflection is a highly valued and widely applied learning approach in higher education. There are many benefits associated with engaging in critical reflection, and it is often integrated into the design of graduate level courses on university teaching as a life-long learning strategy to help ensure that learners build their capacity as…

  12. A Reflective Approach to Teaching Practicum Debriefing (United States)

    Minott, Mark A.


    Over the past 20 years, the teaching profession has embraced the notion of the teacher as reflective practitioner, which has led to an increased emphasis on teacher education programs offering learning experiences that model and encourage reflective practice. This qualitative instrumental case study research explored the usefulness, benefits, and…

  13. Scaffolding students' reflection for science learning (United States)

    Davis, Elizabeth Anna

    Research in recent decades has emphasized the importance of reflection for students learning science, but educators have not reached consensus on the most effective ways to promote reflection, nor has a mechanism explaining the effects of reflection been accepted. Furthermore, many have put forth technology as a vehicle for improving student learning, yet others discount its ability to facilitate real reflection. This research determines whether reflection prompts promote knowledge integration for students working on science projects and what level of prompt specificity best supports students in that endeavor. The Knowledge Integration Environment (KIE) affords investigation of computer-delivered prompts for students completing complex projects. This research takes place in the context of the KIE software and curriculum as used in an eighth grade physical science class. Pilot research on prompts indicated that focusing students on reflection significantly increased knowledge integration. A basic question unanswered by the pilot research was: As students work on projects like those used in KIE, do they merely need to be prompted to reflect, or do they need guidance in determining what to reflect about? The prompts contrasted in this research differ in their specificity. Some students received directed prompts aimed at fostering planning and self-monitoring, while others received generic 'stop and think' prompts. The investigations describe the gross effects of reflection prompts, then attempt to identify a mechanism behind those effects through characterizing the kinds of reflection they elicit and the beliefs about science and learning science of individuals using the prompts. I argue that by engaging in reflection, students identify weaknesses in their knowledge and then are more ready and able to link and distinguish their ideas. Generic prompts are more effective than directed prompts at engaging students in these knowledge integration processes. Autonomous

  14. Variability in response to albuminuria lowering drugs : true or random?

    NARCIS (Netherlands)

    Petrykiv, Sergei I.; de Zeeuw, Dick; Persson, Frederik; Rossing, Peter; Gansevoort, Ron T.; Laverman, Gozewijn D.; Heerspink, Hiddo J. L.

    AIMS Albuminuria-lowering drugs have shown different effect size in different individuals. Since urine albumin levels are known to vary considerably from day- to-day, we questioned whether the between-individual variability in albuminuria response after therapy initiation reflects a random

  15. Asthma Self-Management Model: Randomized Controlled Trial (United States)

    Olivera, Carolina M. X.; Vianna, Elcio Oliveira; Bonizio, Roni C.; de Menezes, Marcelo B.; Ferraz, Erica; Cetlin, Andrea A.; Valdevite, Laura M.; Almeida, Gustavo A.; Araujo, Ana S.; Simoneti, Christian S.; de Freitas, Amanda; Lizzi, Elisangela A.; Borges, Marcos C.; de Freitas, Osvaldo


    Information for patients provided by the pharmacist is reflected in adhesion to treatment, clinical results and patient quality of life. The objective of this study was to assess an asthma self-management model for rational medicine use. This was a randomized controlled trial with 60 asthmatic patients assigned to attend five modules presented by…

  16. Evaluation of bilge water-induced plant genotoxicity using randomly ...

    African Journals Online (AJOL)

    The Random Amplified Polymorphic DNA (RAPD) technique was employed to evaluate the level of DNA alteration in Allium cepa root tips exposed to different concentrations of bilge water (1, 5, 10, 25 and 50%). Compared to the control, DNA polymorphism which was reflected by changes in the RAPD profiles as variation ...

  17. Plasmonic waves of a semi-infinite random nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Afshin [Department of Basic Sciences, Kermanshah University of Technology, Kermanshah, Iran and Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran (Iran, Islamic Republic of)


    The dispersion curves of the plasmonic waves of a semi-infinite random metal-dielectric nanocomposite, consisting of bulk metal embedded with dielectric inclusions, are presented. Two branches of p-polarized surface plasmon-polariton modes are found to exist. The possibility of experimentally observing the surface waves by attenuated total reflection is demonstrated.

  18. Re-thinking reflection in supervision

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    suggested that professional practitioners and students could and should develop their work and skills by thinking critically about their actions. However, over the last twenty years, the ideas about reflective practice – what it means and how it is done – have moved away form their radical roots. The idea......, and practitioners and students are expected to document this, typically in some sort of written record or portfolio. Thus, reflection is often limited to assessment issues, and the original idea of reflection as a modus of critical praxis is reversed and turned into a tool for control and orthodoxy (Kilminster et...... al., 2010). This conceptual paper presents a critical, socio-cultural perspective on the current paradigm or dogma of reflective practice within supervision in professional education and learning. The purpose I to challenge the dogma and critically to analyze and move the debate on reflection...

  19. Particle reflection and TFTR neutral beam diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O`Connor, T.E.; Newman, R.A.; Stevenson, T.N.; von Halle, A.; Williams, M.D.


    Determination of two critical neutral beam parameters, power and divergence, are affected by the reflection of a fraction of the incident energy from the surface of the measuring calorimeter. On the TFTR Neutral Beam Test Stand, greater than 30% of the incident power directed at the target chamber calorimeter was unaccounted for. Most of this loss is believed due to reflection from the surface of the flat calorimeter, which was struck at a near grazing incidence (12{degrees}). Beamline calorimeters, of a ``V``-shape design, while retaining the beam power, also suffer from reflection effects. Reflection, in this latter case, artificially peaks the power toward the apex of the ``V``, complicating the fitting technique, and increasing the power density on axis by 10 to 20%; an effect of import to future beamline designers. Agreement is found between measured and expected divergence values, even with 24% of the incident energy reflected.

  20. Particle reflection and TFTR neutral beam diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O' Connor, T.E.; Newman, R.A.; Stevenson, T.N.; von Halle, A.; Williams, M.D.


    Determination of two critical neutral beam parameters, power and divergence, are affected by the reflection of a fraction of the incident energy from the surface of the measuring calorimeter. On the TFTR Neutral Beam Test Stand, greater than 30% of the incident power directed at the target chamber calorimeter was unaccounted for. Most of this loss is believed due to reflection from the surface of the flat calorimeter, which was struck at a near grazing incidence (12{degrees}). Beamline calorimeters, of a V''-shape design, while retaining the beam power, also suffer from reflection effects. Reflection, in this latter case, artificially peaks the power toward the apex of the V'', complicating the fitting technique, and increasing the power density on axis by 10 to 20%; an effect of import to future beamline designers. Agreement is found between measured and expected divergence values, even with 24% of the incident energy reflected.

  1. Global Explorers Journaling and Reflection Initiative

    Directory of Open Access Journals (Sweden)

    John Bennion


    Full Text Available Research suggests that journaling will increase reflection and improve program outcomes (Bain, et al, 1999; Duerden, et al, 2012 This study involved a partnership with a non-profit, Global Explorers (GEx, which provides international immersion experiences for youth. Their programs are designed to teach youth participants principles of leadership, environmental awareness, service, and science. This study, which tested whether teaching journaling techniques to youth program facilitators would have a positive impact on participant outcomes, addressed the following hypotheses: 1 Greater training in reflective thinking among participants would be associated with higher outcome scores, and 2 Participants in the intervention group (facilitators trained in journaling pedagogy would show greater increases in reflective thinking than comparison group members. Results based on participant self-assessment were significant in testing the first hypothesis; reflective thinking is positively associated with outcome measures, but the intervention group did not show increases in reflective thinking.

  2. Random maintenance policies

    CERN Document Server

    Nakagawa, Toshio


    Exploring random maintenance models, this book provides an introduction to the implementation of random maintenance, and it is one of the first books to be written on this subject.  It aims to help readers learn new techniques for applying random policies to actual reliability models, and it provides new theoretical analyses of various models including classical replacement, preventive maintenance and inspection policies. These policies are applied to scheduling problems, backup policies of database systems, maintenance policies of cumulative damage models, and reliability of random redundant systems. Reliability theory is a major concern for engineers and managers, and in light of Japan’s recent earthquake, the reliability of large-scale systems has increased in importance. This also highlights the need for a new notion of maintenance and reliability theory, and how this can practically be applied to systems. Providing an essential guide for engineers and managers specializing in reliability maintenance a...

  3. Drawing a random number

    DEFF Research Database (Denmark)

    Wanscher, Jørgen Bundgaard; Sørensen, Majken Vildrik


    highly uniform multidimensional draws, which are highly relevant for todays traffic models. This paper shows among others combined shuffling and scrambling seems needless, that scrambling gives the lowest correlation and that there are detectable differences between random numbers, dependent...

  4. Theory of random sets

    CERN Document Server

    Molchanov, Ilya


    This monograph, now in a thoroughly revised second edition, offers the latest research on random sets. It has been extended to include substantial developments achieved since 2005, some of them motivated by applications of random sets to econometrics and finance. The present volume builds on the foundations laid by Matheron and others, including the vast advances in stochastic geometry, probability theory, set-valued analysis, and statistical inference. It shows the various interdisciplinary relationships of random set theory within other parts of mathematics, and at the same time fixes terminology and notation that often vary in the literature, establishing it as a natural part of modern probability theory and providing a platform for future development. It is completely self-contained, systematic and exhaustive, with the full proofs that are necessary to gain insight. Aimed at research level, Theory of Random Sets will be an invaluable reference for probabilists; mathematicians working in convex and integ...

  5. [SPAD prediction of leave based on reflection spectroscopy]. (United States)

    Yang, Hai-Qing; Yao, Jian-Song; He, Yong


    Handheld SPAD meter is often used to measure chlorophyll content of plant and nitrogen level for some species. For plant production automation, however, it loses its popularity due to its point-by-point checking. The authors need to monitor the growing conditions of plant remotely, instantly and nondestructively. In the test, we examined optical fiber reflection spectroscopy used to measure chlorophyll content of some plant leaves, or for their SPAD prediction. The authors picked 120 leaves randomly from our campus ground or trees, among which 70 samples were chosen as calibration set and others as verification set. Each sample was water-cleaned and air-dried. To locate each measuring point precisely when using SPAD meter and spectrometer, the authors drew a circle with a diameter of 10 mm on each leave to be measured. By comparing the spectral curves of various leaves, the authors found that the spectral band between 650-750 nm was significant for SPAD modeling since this range of spectral data of leaves with the same SPAD reading was close to each other. It was showed that leave color was an unnecessary factor for SPAD prediction by reflection spectroscopy. Besides, the authors discovered that LED's narrow spectral range used by SPAD meter should be concerned because optical fiber spectrometer has much more wide spectral range. Based on this awareness, the authors designed an adjustment factor of light to linearly rebuild spectrometer's reflective intensity so that it reached zero outside the band 650-750 nm. Moreover, leave thickness was another influential factor for SPAD prediction since the light of SPAD meter goes through the leave while the reflective spectrometer does not. First, an equation for SPAD prediction was built with uncertain parameters. Then, a standard genetic algorithm was designed with Visual Basic 6.0 for parameter optimization. As a result, the optimal reflection band was narrowed within 683.24-733.91 nm. The result showed that leave

  6. Quasiclassical Random Matrix Theory


    Prange, R. E.


    We directly combine ideas of the quasiclassical approximation with random matrix theory and apply them to the study of the spectrum, in particular to the two-level correlator. Bogomolny's transfer operator T, quasiclassically an NxN unitary matrix, is considered to be a random matrix. Rather than rejecting all knowledge of the system, except for its symmetry, [as with Dyson's circular unitary ensemble], we choose an ensemble which incorporates the knowledge of the shortest periodic orbits, th...

  7. Quantum randomness and unpredictability

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Gregg [Quantum Communication and Measurement Laboratory, Department of Electrical and Computer Engineering and Division of Natural Science and Mathematics, Boston University, Boston, MA (United States)


    Quantum mechanics is a physical theory supplying probabilities corresponding to expectation values for measurement outcomes. Indeed, its formalism can be constructed with measurement as a fundamental process, as was done by Schwinger, provided that individual measurements outcomes occur in a random way. The randomness appearing in quantum mechanics, as with other forms of randomness, has often been considered equivalent to a form of indeterminism. Here, it is argued that quantum randomness should instead be understood as a form of unpredictability because, amongst other things, indeterminism is not a necessary condition for randomness. For concreteness, an explication of the randomness of quantum mechanics as the unpredictability of quantum measurement outcomes is provided. Finally, it is shown how this view can be combined with the recently introduced view that the very appearance of individual quantum measurement outcomes can be grounded in the Plenitude principle of Leibniz, a principle variants of which have been utilized in physics by Dirac and Gell-Mann in relation to the fundamental processes. This move provides further support to Schwinger's ''symbolic'' derivation of quantum mechanics from measurement. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Diffuse light correction for field reflectance measurements (United States)

    Lamarr, John Henry

    The Remote Sensing Group of the Optical Sciences Center at the University of Arizona performs absolute radiometric calibration of Earth-viewing sensors using vicarious methods. The reflectance and irradiance-based methods require the nadir-view reflectance of a calibration site at sensor overpass. Errors in these reflectance data contribute directly to errors in the retrieved at sensor radiance, and therefore errors in the calibration. This research addresses two areas of improvement for the reflectance retrieval. The discreet laboratory data of the reference panel is spectrally interpolated using the measured hemispherical reflectance rather than a polynomial fit. This interpolation better fits an absorption feature of the reference material near 2200 nm. The desired reflectance is due to the directly- transmitted solar irradiance, but field measurements also include irradiance due to diffuse light. Non-lambertian properties of the reference and surface cause the ratio of the reflected total radiances to differ from the ratio of the reflected solar radiances. This difference can be corrected using additional field measurements, shaded surface/shaded-reference, output from a radiative transfer code, RTC-only, or a combination of both, shaded-reference. For the shaded-reference and RTC-only methods the shape of the bi-directional reflectance factor of the surface must be known to better than 10% to maintain a 2% accuracy for the retrievals, while the shaded-surface/shaded-reference method does not use the surface BRF. All three methods were applied to measurements of calibrated reflectance tarpaulins, and to measurements made at White Sands Missile Range. These data demonstrate that the shaded-surface/shaded-reference and RTC-only methods improve the surface reflectance retrieval, while the shaded-reference method is too sensitive to variations between the actual and modeled diffuse sky irradiance to be useful. This research represents significant improvements in

  9. Instructions for processing of near field reflectivity test data and derivation of far field reflectivity indicators

    NARCIS (Netherlands)

    Roo, F. de; Lutgendorf, D.; Wessels, P.W.


    Sound reflectivity is one of the intrinsic acoustical characteristics of noise reducing devices (NRD’s). It describes which percentage of an incident sound field is reflected back towards the opposite side of the road. The reflectivity is determined by the absorption properties of the material of

  10. Reflectance changes in white reflectance standards measured in different instruments with 0/d geometry


    Campos Acosta, Joaquín; Pons Aglio, Alicia; Martín, Jorge


    Spectrophotometric errors in measurement of reflectance 0/d widely studied. Calibration standard (white standard) is assumed to be constant. 0/d reflectance measurement are done with an integrating sphere. Sphere error corrections Procedure developed at NPL: correction factors for the correct inclusion and exclusion of the specular component of reflectance.

  11. Reflective Practice for Psychology Students: The Use of Reflective Journal Feedback in Higher Education (United States)

    Bruno, Andreina; Dell'Aversana, Giuseppina


    Reflective journals have emerged as an effective means of monitoring and developing reflective practice in higher education, as part of a wider metacognitive strategy to transform traditional learning approaches. In addition, assessment procedures of reflective journals appear to be an important factor in enhancing commitment to learning and…

  12. Exact Simulation of Polarized Light Reflectance by Particle Deposits (United States)

    Ramezan Pour, B.


    The research examines two methods for prediction of polarized bidirectional reflectance and transmittance from plane parallel layers of randomly distributed, wavelength—sized particles. The first method is based on an exact superposition solution to Maxwell's time harmonic wave equations for a deposit of spherical particles that are exposed to a plane incident wave. We use a FORTRAN-90 implementation of this solution (the Multiple Sphere T Matrix (MSTM) code), coupled with parallel computational platforms, to directly simulate the reflection from particle layers via a configurational averaging strategy. In this approach, a target, in the form of a cylindrical volume with radius well in excess of thickness and containing a collection of monodisperse, non-overlapping spheres, is created using Monte Carlo sampling methods. The polarimetric scattering properties of the target, for plane wave incidence, are then computed using MSTM. This process is repeated over multiple sampled targets to calculate the random—medium reflectance and transmittance properties of the particles, as a function of sphere size parameter, refractive index, and sphere volume fraction. The second method examined is based upon the vector radiative transport equation (RTE). Mie theory is used in our RTE model to predict the extinction coefficient, albedo, and scattering phase function of the particles, and the solution of the RTE is obtained from adding—doubling method applied to a plane—parallel configuration. For sphere size parameters of order unity, the results indicate that the MSTM and RTE predictions, for the most part, converge when the particle volume fraction decreases below five percent. With regard to the MSTM method, a considerable number of target samples can be required to generate averaged scattering matrices that display the expected polarimetric features of reflection from a randomly inhomogenous plane parallel layer. The MSTM results do, however, reveal characteristics

  13. Random reward priming is task-contingent

    DEFF Research Database (Denmark)

    Ásgeirsson, Árni Gunnar; Kristjánsson, Árni


    Consistent financial reward of particular features influences the allocation of visual attention in many ways. More surprising are 1-trial reward priming effects on attention where reward schedules are random and reward on one trial influences attentional allocation on the next. Those findings...... are thought to reflect that rewarded features become more salient than unrewarded ones on the subsequent trial. Here we attempt to conceptually replicate this effect, testing its generalizability. In three versions of an analogous paradigm to the additional singleton paradigm involving singleton search...... for a Gabor patch of odd spatial frequency we found no evidence of reward priming, while we only partially replicate the reward priming in the exact original paradigm tested by Hickey and colleagues. The results cast doubt on the proposal that random reward enhances salience, suggested in the original papers...

  14. Implementing and evaluating reflective practice group sessions. (United States)

    McGrath, Deidre; Higgins, Agnes


    The rapidly changing and developing arenas of biological and medical technology, coupled with a myriad of social concerns and issues affecting individual, family and societal health, necessitates that nursing practitioners engage themselves fully with patients in the pursuit of health and healing. The above factors have not only served as catalysts in the development of educational curricula in general but also nursing curricula. Reflection in these curricula is often considered an appropriate vehicle for the analysis of nursing practice, fostering not only an understanding of nurse's work but also the development of critically thoughtful approaches essential for providing nursing care in complex environments [Duke, S., Appleton, J., 2000. The use of reflection in a palliative care programme: a qualitative study of the development of reflective skills over an academic year. J. Adv. Nurs. 32 (6), 1557-1568]. Consequently, nurse educators are being called upon to develop nurses who are reflective practitioners. The focus of this paper is on an exploration of issues that arose from the implementation of reflective sessions with a group of qualified nurses undertaking a diploma in nursing. This paper addresses the challenges experienced in the introduction of reflection as a teaching method. Recommendations for other lecturers when using this approach are also provided. It is anticipated this paper will provide practical advice and guidance for educators who wish to use reflective sessions to enhance the educational experience of their nursing students.

  15. Effects of Foliar Insecticides on Leaf-Level Spectral Reflectance of Soybean. (United States)

    Alves, Tavvs M; Marston, Zachary P; MacRae, Ian V; Koch, Robert L


    Pest-induced changes in plant reflectance are crucial for the development of pest management programs using remote sensing. However, it is unknown if plant reflectance data is also affected by foliar insecticides applied for pest management. Our study assessed the effects of foliar insecticides on leaf reflectance of soybean. A 2-yr field trial and a greenhouse trial were conducted using randomized complete block and completely randomized designs, respectively. Treatments consisted of an untreated check, a new systemic insecticide (sulfoxaflor), and two representatives of the most common insecticide classes used for soybean pest management in the north-central United States (i.e., λ-cyhalothrin and chlorpyrifos). Insecticides were applied at labeled rates recommended for controlling soybean aphid; the primary insect pest in the north-central United States. Leaf-level reflectance was measured using ground-based spectroradiometers. Sulfoxaflor affected leaf reflectance at some red and blue wavelengths but had no effect at near-infrared or green wavelengths. Chlorpyrifos affected leaf reflectance at some green, red, and near-infrared wavelengths but had no effect at blue wavelengths. λ-cyhalothrin had the least effect on spectral reflectance among the insecticides, with changes to only a few near-infrared wavelengths. Our results showing immediate and delayed effects of foliar insecticides on soybean reflectance indicate that application of some insecticides may confound the use of remote sensing for detection of not only insects but also plant diseases, nutritional and water deficiencies, and other crop stressors. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please email:

  16. Study on the key technology of spectral reflectance reconstruction based on a single pixel detector (United States)

    Li, Bei; Zhang, Haojun; Zhang, Leihong; Kang, Yi; Zhan, Wenjie; Yi, Wenjuan; Zhang, Dawei


    In order to realize an accurate reconstruction of images, this article explores image reconstruction from a spectrum point of view. Combined with a principal component analysis method and compressed sensing algorithm, this article puts forward a spectral reflectance reconstruction algorithm based on a single pixel detector, and compares the different modulation matrixes for DMD in the experiment. From subjective evaluation and three objective evaluation methods: color difference, peak signal-to-noise ratio and structural similarity, we compare and analyze the reconstruction effects of two modulation methods: random modulation and Hadamard modulation. The experimental results show that the color difference of the spectral reflectance reconstruction method of a single pixel detector based on random modulation is smaller, the similarity of the structure is higher, and the peak signal-to-noise ratio is greater than Hadamard modulation. To sum up, the spectral reflectance reconstruction algorithm of a single pixel detector based on random modulation is better than Hadamard modulation, which is more conducive to an accurate reconstruction of spectral reflectance.

  17. Glue Film Thickness Measurements by Spectral Reflectance

    Energy Technology Data Exchange (ETDEWEB)

    B. R. Marshall


    Spectral reflectance was used to determine the thickness of thin glue layers in a study of the effect of the glue on radiance and reflectance measurements of shocked-tin substrates attached to lithium fluoride windows. Measurements based on profilometry of the components were found to be inaccurate due to flatness variations and deformation of the tin substrate under pressure during the gluing process. The accuracy of the spectral reflectance measurements were estimated to be ±0.5 μm, which was sufficient to demonstrate a convincing correlation between glue thickness and shock-generated light.

  18. The Reflection Effect in Eclipsing Binaries (United States)

    Gropp, Jeffrey D.; Prsa, Andrej


    Using a database of eclipsing binaries (EBs) from the Kepler space telescope, we identified star systems which displayed characteristics corresponding to the reflection effect. The reflection effect is the brightening of one star due to irradiation by its companion. We found 40 candidates amongst the nearly 2,800 EBs in the database. We analyze these candidates and derive parameters and properties of each system using the PHOEBE modeling program. We examine each model fit using probabilistic inference in order to statistically evaluate the best fit model. The model critically tests the reflection effect and provides physical constraints on the principal parameters.

  19. Wave Reflection in 3D Conditions

    DEFF Research Database (Denmark)

    Zanuttigh, Barbara; Andersen, Thomas Lykke


    Based on recent experiments carried out in wave basin on breakwaters with armour layer of rocks and cubes, this paper examines the dependence of the reflection coefficient on wave directional spreading and obliquity. Results suggest that long-crested and short-crested waves give similar reflection....... The reflection coefficient is markedly dependent on the wave angle of incidence. The performance of formulae available in the literature is checked against the new dataset and a significant improvement is proposed by including the wave obliquity factor that appears in the traditional expression...

  20. Two beam surface fluctuation specular reflection spectroscopy. (United States)

    Raudsepp, Allan; Fretigny, Christian; Lequeux, François; Talini, Laurence


    In surface fluctuation specular reflection spectroscopy (SFSRS) deflections of a specularly reflected laser beam are used to characterize thermally excited surface waves. Here we report on a new two beam version of SFSRS in which the deflections of two reflected laser beams from separate locations on a surface are correlated. We demonstrate that this new two beam SFSRS technique can be used to determine directly the power spectrum of height fluctuation of thermally excited surface waves over a large range of both frequencies and wavevectors. In addition, we show that the technique is well suited for materials ranging from simple liquids to complex liquids and soft solids, including turbid materials.

  1. Personal Professional Reflection as Interdisciplinary Problem

    Directory of Open Access Journals (Sweden)

    Rezvan Oksana


    Full Text Available Consideration of professional reflection as interdisciplinary problem is the necessary condition of quality analysis for personal professional becoming. Personal becoming in a profession is related to forming the necessary professional skills of a person, behaviour stereotypes which is the area of pedagogics. Reflection processes are inalienable part of self-knowledge of a person which result must lead to his self-perfection (including professional one and studying within the psychology increasingly. Thus the aim of the article is to ground the determination of professional reflection as an interdisciplinary problem in pedagogics and psychology.

  2. [Contrastive analysis on soil alkalinization predicting models based on measured reflectance and TM image reflectance]. (United States)

    Zhang, Fang; Xiong, Hei-Gang; Long, Tao; Lu, Wen-Juan


    Based on the monitored data of soil pH and measured Vis-NIR reflectance on spot in Qitai oasis alkalinized area in Xinjiang, as well as comparison of the relationship between measured reflectance and soil pH and the relationship between TM reflectance and soil pH, both of the reflectance multivariate linear regression models were built to evaluate soil alkalinization level, and the model accuracy of pH fitting was discussed with error inspection of post-sample. The results showed that there is a significant positive correlation between soil pH and reflectance. With pH rising the reflectance increased concurrently. So the alkalinization soil characterized by hardening had good spectral response characteristics. Both measured reflectance and TM image reflectance had good potential ability for change detection of the alkalinization soil. The pH predicting model of measured reflectance had higher accuracy and the major error was from different hardening state. If building model by TM reflectance directly, the accuracy of fitting was lower because of the vegetation information in image spectrum. With the vegetation factor removed with NDVI, the accuracy of TM predicting model was near the accuracy of measured reflectance predicting model, and both of the model levels were good.


    Heffron, Mary Claire; Reynolds, Diane; Talbot, Bronwyn


    This article proposes how group reflective supervision, informed by the theory of reflective functioning, may provide a powerful method for developing reflective capacity of staff serving families, infants, and young children in multidisciplinary settings. An explanation of reflective functioning, related research, and its relevance to relational treatment and preventive intervention are discussed. Other approaches to reflective practice are referenced. We describe the necessary tension and encounters with distressing affect that mark reflective supervision groups using this focus. In addition, we identify areas of heightened difficulty in infant family work and describe how a group supervision process that enables use of self alongside perspectives of others may address these challenges while leading to increased reflective capacity among participants. Finally, we touch on relevant research on group supervision and parameters of size and focus, and highlight facilitation skills needed to create group safety and coherence. Areas for further study are proposed. © 2016 Michigan Association for Infant Mental Health.

  4. Telerobotic Control Architecture Including Force-Reflection

    National Research Council Canada - National Science Library

    Murphy, Mark


    This report describes the implementation of a telerobotic control architecture to manipulate a standard six-degree-of-freedom robot via a unique seven-degree-of-freedom force-reflecting exoskeleton...

  5. Force Reflection Algorithms for Exoskeleton Controllers

    National Research Council Canada - National Science Library

    Bryfogle, Mark


    This research effort investigated the kinematics and dynamics of open chain, serial linkage mechanisms with specific emphasis placed upon the application of this linkage as a force reflecting exoskeleton mechanism...

  6. Do hand outcome measures reflect cultural influences?

    Directory of Open Access Journals (Sweden)

    Çiğdem Öksüz


    Conclusion: None of three questionnaires have satisfactory results for reflecting the problematic activities among hand injured Turkish people. Open ended interviews should be irrevocable part of assessment process in order to describe a person-center treatment program.

  7. Projection/Reflection Heads-up Display (United States)

    National Aeronautics and Space Administration — To address the NASA need for an EVA information display device, Physical Optics Corporation (POC) proposes to develop a new Projection/Reflection Heads-up Display...

  8. Contemplative interaction: alternating between immersion and reflection

    DEFF Research Database (Denmark)

    Hansen, Lone Koefoed


    the user alternate between reflection and immersion. By analysing two interactive artefacts, an artwork and a design proposal, this paper investigates how contemplation appears in and can be transferred to interactive artefacts aimed at providing seductive, fun and interesting experiences....

  9. Automatic specular reflections removal for endoscopic images (United States)

    Tan, Ke; Wang, Bin; Gao, Yuan


    Endoscopy imaging is utilized to provide a realistic view about the surfaces of organs inside the human body. Owing to the damp internal environment, these surfaces usually have a glossy appearance showing specular reflections. For many computer vision algorithms, the highlights created by specular reflections may become a significant source of error. In this paper, we present a novel method for restoration of the specular reflection regions from a single image. Specular restoration process starts with generating a substitute specular-free image with RPCA method. Then the specular removed image was obtained by taking the binary weighting template of highlight regions as the weighting for merging the original specular image and the substitute image. The modified template was furthermore discussed for the concealment of artificial effects in the edge of specular regions. Experimental results on the removal of the endoscopic image with specular reflections demonstrate the efficiency of the proposed method comparing to the existing methods.

  10. Metal nano-grid reflective wave plate. (United States)

    Pang, Y; Gordon, R


    We propose an optical wave plate using a metal nano-grid. The wave plate operates in reflection mode. A single-mode truncated modematching theory is presented as a general method to design such nano-grid wave plates with the desired phase difference between the reflected TM and TE polarizations. This analytical theory allows angled incidence calculations as well, and numerical results agree-well with comprehensive finite-difference time-domain electromagnetic simulations. Due to the subwavelength path-length, the reflective wave plate is expected to have improved broad-band functionality over existing zero-order transmissive wave plates, for which an example is provided. The proposed wave plate is simple and compact, and it is amenable to existing nanofabrication techniques. The reflective geometry is especially promising for applications including liquid-crystal displays and laser feedback experiments.

  11. A new specular reflection optimization algorithm

    National Research Council Canada - National Science Library

    Qi, Qisong; Xu, Gening; Fan, Xiaoning; Wang, Jun


    ...; then the algorithm is used to solve discrete engineering optimization problems and the results indicate that the Specular Reflection Algorithm has higher computation efficiency and extensive prospect for engineering application.

  12. Reflection and transmission for layered composite materials (United States)

    Graglia, Roberto D.; Uslenghi, Piergiorgio L. E.


    A layered planar structure consisting of different bianisotropic materials separated by jump-immittance sheets is considered. Reflection and transmission coefficients are determined via a chain-matrix algorithm. Applications are important for radomes and radar-absorbing materials.

  13. Social media:A psychology postgraduate's reflection


    Peach, Donna; Erskine-Shaw, Marianne


    Social media is increasingly being utilised as a means of sharing research and ideas, showing your skill-set and collecting data. This article reflects on the positives and potential pitfalls for psychology postgraduates of this burgeoning area.

  14. Reflection of sine-Gordon breathers

    DEFF Research Database (Denmark)

    Olsen, O. H.; Samuelsen, Mogens Rugholm


    the breather is almost annihilated. At an active termination the breather is reflected into a breather of increased energy possibly followed by fluxons, antifluxons, or even breathers. Journal of Applied Physics is copyrighted by The American Institute of Physics....

  15. Investigation of reflective cracking mitigation techniques. (United States)


    In the state of Florida, an asphalt rubber membrane interlayer (ARMI) has been commonly used as a reflective cracking (RC) mitigation method, but inconsistent performance of an ARMI has been observed in the field. Moreover, the Heavy Vehicle Simulato...

  16. Investigation of reflective cracking mitigation techniques : [summary]. (United States)


    When new asphalt is placed over concrete or : asphalt pavement, cracks or joints in the old : layer can appear in the new overlay; this is : called reflective cracking (RC). In current Florida : practice, an asphalt rubber membrane interlayer : (ARMI...

  17. Leaf Reflectances: Perkin-Elmer (OTTER) (United States)

    National Aeronautics and Space Administration — Absolute (diffuse & specular) reflectance of leaves measured in the lab by Perkin-Elmer spectrophotometer to aid in understanding remotely sensed spectral data

  18. Lamont Doherty Seismic Reflection Scanned Images (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains single channel seismic reflection profiles as provided to NGDC by Lamont Doherty Earh Observatory (LDEO). The profiles were originally...

  19. On automatic visual inspection of reflective surfaces

    DEFF Research Database (Denmark)

    Kulmann, Lionel


    . The first is the inspection of highly reflective aluminum sheets, used by the Danish company Bang & Olufsen, as a part of the exterior design and general appearance of their audio and video products. The second is the inspection of IBM hard disk read/write heads for defects during manufacturing. We have...... lighting methods in a framework, general usable for inspecting reflective surfaces. Special attention has been given to the design of illumination techniques to enhance defects of highly reflective aluminum sheets. The chosen optical system setup has been used to enhance surface defects of other reflective...... in algorithms for detecting 3-dimensional surface damages based on images from a novel structured lighting setup enhancing the appearance of these defects in specular surfaces. A hardware implementable polynomial classifier structure has been described and compared to better known techniques based...

  20. Characterization of Stationary Distributions of Reflected Diffusions (United States)


    11 ∗Partially supported by NSF grants CMMI -1052750 (formerly 0928154), CMMI - 1114608 and ARO grant W911NF-12-1-0222 AMS...his PhD thesis [47]. However, the results of [47] do not apply to reflected diffusions in non-smooth domains in RJ . Kurtz and Stockbridge [29, 30...Duarte, M. (2012). Stationary distribution for spinning reflecting diffusions. PhD Thesis , University of Washington, 2012, WA. [16] Dupuis, P. and

  1. Experiential reflective learning and comfort zone

    Directory of Open Access Journals (Sweden)

    Jan Nehyba


    Full Text Available The article deals with the issue of experiential reflective learning. Firstlyit aims to discuss the concept of comfort zone in this area. It goes beyond the usualdefinition of the domestic comfort zone and it reflects in terms of experiential reflectivelearning in the world. The conclusions point to possible parallels with the concept ofcomfort zones and K. Lewin theory. Overall, the article focuses on topics that help toexpand the view on the issue of comfort zone.

  2. Lamp method and apparatus using multiple reflections (United States)

    MacLennan, Donald A.; Turner, Brian; Kipling, Kent


    A method wherein the light in a sulfur or selenium lamp is reflected through the fill a multiplicity of times to convert ultraviolet radiation to visible. A light emitting device comprised of an electrodeless envelope which bears a light reflecting covering around a first portion which does not crack due to differential thermal expansion and which has a second portion which comprises a light transmissive aperture.

  3. Brain potentials index executive functions during random number generation. (United States)

    Joppich, Gregor; Däuper, Jan; Dengler, Reinhard; Johannes, Sönke; Rodriguez-Fornells, Antoni; Münte, Thomas F


    The generation of random sequences is considered to tax different executive functions. To explore the involvement of these functions further, brain potentials were recorded in 16 healthy young adults while either engaging in random number generation (RNG) by pressing the number keys on a computer keyboard in a random sequence or in ordered number generation (ONG) necessitating key presses in the canonical order. Key presses were paced by an external auditory stimulus to yield either fast (1 press/800 ms) or slow (1 press/1300 ms) sequences in separate runs. Attentional demands of random and ordered tasks were assessed by the introduction of a secondary task (key-press to a target tone). The P3 amplitude to the target tone of this secondary task was reduced during RNG, reflecting the greater consumption of attentional resources during RNG. Moreover, RNG led to a left frontal negativity peaking 140 ms after the onset of the pacing stimulus, whenever the subjects produced a true random response. This negativity could be attributed to the left dorsolateral prefrontal cortex and was absent when numbers were repeated. This negativity was interpreted as an index for the inhibition of habitual responses. Finally, in response locked ERPs a negative component was apparent peaking about 50 ms after the key-press that was more prominent during RNG. Source localization suggested a medial frontal source. This effect was tentatively interpreted as a reflection of the greater monitoring demands during random sequence generation.

  4. Coded Random Access

    DEFF Research Database (Denmark)

    Paolini, Enrico; Stefanovic, Cedomir; Liva, Gianluigi


    , in which the structure of the access protocol can be mapped to a structure of an erasure-correcting code defined on graph. This opens the possibility to use coding theory and tools for designing efficient random access protocols, offering markedly better performance than ALOHA. Several instances of coded......The rise of machine-to-machine communications has rekindled the interest in random access protocols as a support for a massive number of uncoordinatedly transmitting devices. The legacy ALOHA approach is developed under a collision model, where slots containing collided packets are considered...... as waste. However, if the common receiver (e.g., base station) is capable to store the collision slots and use them in a transmission recovery process based on successive interference cancellation, the design space for access protocols is radically expanded. We present the paradigm of coded random access...

  5. Optical Reflectance Measurements for Commonly Used Reflectors (United States)

    Janecek, Martin; Moses, William W.


    When simulating light collection in scintillators, modeling the angular distribution of optical light reflectance from surfaces is very important. Since light reflectance is poorly understood, either purely specular or purely diffuse reflectance is generally assumed. In this paper we measure the optical reflectance distribution for eleven commonly used reflectors. A 440 nm, output power stabilized, un-polarized laser is shone onto a reflector at a fixed angle of incidence. The reflected light's angular distribution is measured by an array of silicon photodiodes. The photodiodes are movable to cover 2pi of solid angle. The light-induced current is, through a multiplexer, read out with a digital multimeter. A LabVIEW program controls the motion of the laser and the photodiode array, the multiplexer, and the data collection. The laser can be positioned at any angle with a position accuracy of 10 arc minutes. Each photodiode subtends 6.3deg, and the photodiode array can be positioned at any angle with up to 10 arc minute angular resolution. The dynamic range for the current measurements is 10 5:1. The measured light reflectance distribution was measured to be specular for several ESR films as well as for aluminum foil, mostly diffuse for polytetrafluoroethylene (PTFE) tape and titanium dioxide paint, and neither specular nor diffuse for Lumirrorreg, Melinexreg and Tyvekreg. Instead, a more complicated light distribution was measured for these three materials.

  6. Reflective masks for extreme ultraviolet lithography

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Khanh Bao [Univ. of California, Berkeley, CA (United States)


    Extreme ultraviolet lithographic masks are made by patterning multilayer reflective coatings with high normal incidence reflectivity. Masks can be patterned by depositing a patterned absorber layer above the coating or by etching the pattern directly into the coating itself. Electromagnetic simulations showed that absorber-overlayer masks have superior imaging characteristics over etched masks (less sensitive to incident angles and pattern profiles). In an EUVL absorber overlayer mask, defects can occur in the mask substrate, reflective coating, and absorber pattern. Electromagnetic simulations showed that substrate defects cause the most severe image degradation. A printability study of substrate defects for absorber overlayer masks showed that printability of 25 nm high substrate defects are comparable to defects in optical lithography. Simulations also indicated that the manner in which the defects are covered by multilayer reflective coatings can affect printability. Coverage profiles that result in large lateral spreading of defect geometries amplify the printability of the defects by increasing their effective sizes. Coverage profiles of Mo/Si coatings deposited above defects were studied by atomic force microscopy and TEM. Results showed that lateral spread of defect geometry is proportional to height. Undercut at defect also increases the lateral spread. Reductions in defect heights were observed for 0.15 μm wide defect lines. A long-term study of Mo/Si coating reflectivity revealed that Mo/Si coatings with Mo as the top layer suffer significant reductions in reflectivity over time due to oxidation.

  7. On the reflectance of dust in comets (United States)

    Zubko, Evgenij; Videen, Gorden; Shkuratov, Yuriy; Hines, Dean C.


    Reflectance of cometary dust is a key parameter used in the characterization of comets. In the literature, the reflectance of single-scattering cometary dust particles is widely assumed to be the same as that of the cometary nucleus. We discuss this assumption and demonstrate its inconsistency with photometric observations of comets, laboratory optical measurements, and numerical simulation of light scattering from single-scattering dust particles and particulate surfaces composed of the same particles. We estimate the reflectance of cometary dust particles using a comprehensive physical model of polarization measured in comets over wide range of phase angle and at different wavelengths in the visible. The model predicts that the reflectance of dust in comets inversely correlates with their maximum of positive polarization Pmax. We find that even the darkest dust particles appearing in comets with the highest Pmax, reflect considerably more incident solar-radiation energy, up to 200%, compared to what is thought for cometary nuclei. We also find that the reflectance retrieved from polarimetry in the visible appears in good quantitative accordance with previous estimations from infrared observations of comets. Our findings suggest that the dust production of comets is currently overestimated and may require revision.

  8. Students’ Reflections on Writing in ESP

    Directory of Open Access Journals (Sweden)

    Galina Kavaliauskienė


    Full Text Available Active participation of students in the self-evaluation of their learning and the development of reflective thinking are the key features of successful learning. This research is aimed at investigating influence of students’ self-assessment on writing in English for Specific Purposes (ESP. The study employed a survey on the usefulness of different written tasks and students‘ reflections on their benefits to language mastery. The assignments included various contributions to portfolios such as essays, summaries of professional texts, outlines of oral presentations, creative computer tasks as well as students‘ written self-assessment notes, i.e. their reflections on various classroom activities. The research involved the students who study Social Sciences at Mykolas Romeris University. The results demonstrated that self-assessment was beneficial to students’ linguistic development. The reflections reveal the attitudes to various assignments and judgments of their usefulness in learning. Reflective practice might help teachers develop ways of dealing with specific difficulties and improve the quality of teaching. Training learners to reflect on learning outcomes is beneficial from the perspective of lifelong learning.

  9. Reflective and refractive objects for mixed reality. (United States)

    Knecht, Martin; Traxler, Christoph; Winklhofer, Christoph; Wimmer, Michael


    In this paper, we present a novel rendering method which integrates reflective or refractive objects into a differential instant radiosity (DIR) framework usable for mixed-reality (MR) applications. This kind of objects are very special from the light interaction point of view, as they reflect and refract incident rays. Therefore they may cause high-frequency lighting effects known as caustics. Using instant-radiosity (IR) methods to approximate these high-frequency lighting effects would require a large amount of virtual point lights (VPLs) and is therefore not desirable due to real-time constraints. Instead, our approach combines differential instant radiosity with three other methods. One method handles more accurate reflections compared to simple cubemaps by using impostors. Another method is able to calculate two refractions in real-time, and the third method uses small quads to create caustic effects. Our proposed method replaces parts in light paths that belong to reflective or refractive objects using these three methods and thus tightly integrates into DIR. In contrast to previous methods which introduce reflective or refractive objects into MR scenarios, our method produces caustics that also emit additional indirect light. The method runs at real-time frame rates, and the results show that reflective and refractive objects with caustics improve the overall impression for MR scenarios.

  10. Developing and maintaining reflection in clinical journals. (United States)

    Paterson, B L


    There is a pressing need in today's world for nurses who are willing and able to transform health care. Teaching strategies that foster reflection are in order. The use of dialogue journals has been widely reported in the nursing literature as an effective strategy for assisting students to reflect about learning experiences in the clinical area. Despite the promise that journal writing will enhance students' ability to reflect on their clinical learning experiences, not all students respond positively to journal writing as a learning tool. The paper is a discussion of some of the common difficulties that arise in the use of clinical journals as a reflective strategy in nursing education. Common problems in the use of clinical journals include procrastination; superficial, nonreflective entries; waning enthusiasm about the activity; and unwillingness or inability to reflect. The possible etiologies for these problems will be explored. Specifically, the paper will focus on ways to prevent or minimize these concerns by maintaining and enhancing the factors required for students to reflect in clinical journals.

  11. Power reflectance testing in newborns and infants. (United States)

    Lima, Ticianna Garambone de Cerqueira; Becker, Helena Maria Gonçalves; Becker, Celso Gonçalves; Ferreira, Daniele Barreto da Cunha; Resende, Camilo Brandão de; Guimarães, Roberto Eustáquio Santos


    Auditory screening in newborns allows for detection of hearing problems early in life. However, middle ear diseases can make the diagnosis more difficult. To evaluate the power reflectance test as an indicator of the middle ear disease and to compare it to tympanometry. Case study evaluating 105 newborns and infants who participated in the audiology screening in 2013. The following exams were performed: transient otoacoustic emissions, power reflectance, and tympanometry. In the optoacoustic emission evaluation, approximately 95% of the subjects passed the test. The specificity of power reflectance in all frequencies studied ranged from 75.3% to 95.9%, and that of tympanometry at 1000Hz ranged from 83% to 87.2%; there was agreement among these exams. The outcome of power reflectance tests at 2000Hz and 3000Hz showed a correlation with tympanometry and otoacoustic emissions, and these were the most appropriate frequencies to determine middle ear disease through power reflectance measurement. It was also observed that values of power reflectance above reference levels suggested the presence of fluid in the middle ear, and thus a conductive hearing loss. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  12. The Effects of Reflective Training on the Disposition of Critical Thinking for Nursing Students in China: A Controlled Trial


    Caihong Zhang, Ph.D.; Huiying Fan, MSN; Jieqiong Xia, MSN; Honghua Guo, Ph.D.; Xinjun Jiang, MSN; Yane Yan, MSN


    Purpose: The aim of this study was to evaluate the effects of reflective trainings for nursing students on their critical thinking disposition. Methods: A total of 157 senior undergraduate nursing students sampled from Hainan Medical University in China participated in this study in 2014. They were randomly divided into experimental and control groups. The experimental group students were provided the reflective training during their entire 12-month clinical internship, whereas students in...

  13. Incorporating Self and Peer Assessment in Reflective Teaching Practices

    Directory of Open Access Journals (Sweden)

    Ni Made Ratminingsih


    Full Text Available More currently literature reviews suggests the use of authentic assessment, which aims to involve students to be more responsible with their learning. This article reports the findings of a descriptive study on student teachers’ perception on the use of self and peer assessment to give evaluation on planning the lesson and teaching performance in Reflective Teaching Class. There were 100 samples taken randomly from 234 students in a survey using questionnaire and 15 students participating in the focus group discussion (FGD. The finding from the questionnaire shows that they had a very positive perception toward the use of self and peer assessment. Additionally, from the FGD, they conveyed by practicing doing self assessment, they could learn to see self performance deeply, strengths and weaknesses. From peer-assessment, they could learn collaboratively from feedback given by peers how to make a better lesson plan and perform a more effective teaching. Hence, self and peer assessment is considered beneficial for preparing the real teaching practicum and future career development. However, there are some problems challenged them, such as feeling subjectivity in assessing both self or peers, embarrassed and less confidence, and time constraints to make evaluation and reflection in the classroom

  14. Reflectively coupled waveguide photodetector for high speed optical interconnection. (United States)

    Hsu, Shih-Hsiang


    To fully utilize GaAs high drift mobility, techniques to monolithically integrate In0.53Ga0.47As p-i-n photodetectors with GaAs based optical waveguides using total internal reflection coupling are reviewed. Metal coplanar waveguides, deposited on top of the polyimide layer for the photodetector's planarization and passivation, were then uniquely connected as a bridge between the photonics and electronics to illustrate the high-speed monitoring function. The photodetectors were efficiently implemented and imposed on the echelle grating circle for wavelength division multiplexing monitoring. In optical filtering performance, the monolithically integrated photodetector channel spacing was 2 nm over the 1,520-1,550 nm wavelength range and the pass band was 1 nm at the -1 dB level. For high-speed applications the full-width half-maximum of the temporal response and 3-dB bandwidth for the reflectively coupled waveguide photodetectors were demonstrated to be 30 ps and 11 GHz, respectively. The bit error rate performance of this integrated photodetector at 10 Gbit/s with 2(7)-1 long pseudo-random bit sequence non-return to zero input data also showed error-free operation.

  15. A discrete fractional random transform


    Liu, Zhengjun; Zhao, Haifa; Liu, Shutian


    We propose a discrete fractional random transform based on a generalization of the discrete fractional Fourier transform with an intrinsic randomness. Such discrete fractional random transform inheres excellent mathematical properties of the fractional Fourier transform along with some fantastic features of its own. As a primary application, the discrete fractional random transform has been used for image encryption and decryption.

  16. Characterizing the reflectivity of handheld display devices. (United States)

    Liu, Peter; Badano, Aldo


    With increased use of handheld and tablet display devices for viewing medical images, methods for consistently measuring reflectivity of the devices are needed. In this note, the authors report on the characterization of diffuse reflections for handheld display devices including mobile phones and tablets using methods recommended by the American Association of Physicists in Medicine Task Group 18 (TG18). The authors modified the diffuse reflectance coefficient measurement method outlined in the TG18 report. The authors measured seven handheld display devices (two phones and five tablets) and three workstation displays. The device was attached to a black panel with Velcro. To study the effect of the back surface on the diffuse reflectance coefficient, the authors created Styrofoam masks with different size square openings and placed it in front of the device. Overall, for each display device, measurements of illuminance and reflected luminance on the display screen were taken. The authors measured with no mask, with masks of varying size, and with display-size masks, and calculated the corresponding diffuse reflectance coefficient. For all handhelds, the diffuse reflectance coefficient measured with no back panel were lower than measurements performed with a mask. The authors found an overall increase in reflectivity as the size of the mask decreases. For workstations displays, diffuse reflectance coefficients were higher when no back panel was used, and higher than with masks. In all cases, as luminance increased, illuminance increased, but not at the same rate. Since the size of handheld displays is smaller than that of workstation devices, the TG18 method suffers from a dependency on illumination condition. The authors show that the diffuse reflection coefficients can vary depending on the nature of the back surface of the illuminating box. The variability in the diffuse coefficient can be as large as 20% depending on the size of the mask. For all measurements

  17. Reflectance, illumination, and appearance in color constancy (United States)

    McCann, John J.; Parraman, Carinna; Rizzi, Alessandro


    We studied color constancy using a pair of identical 3-D Color Mondrian displays. We viewed one 3-D Mondrian in nearly uniform illumination, and the other in directional, nonuniform illumination. We used the three dimensional structures to modulate the light falling on the painted surfaces. The 3-D structures in the displays were a matching set of wooden blocks. Across Mondrian displays, each corresponding facet had the same paint on its surface. We used only 6 chromatic, and 5 achromatic paints applied to 104 block facets. The 3-D blocks add shadows and multiple reflections not found in flat Mondrians. Both 3-D Mondrians were viewed simultaneously, side-by-side. We used two techniques to measure correlation of appearance with surface reflectance. First, observers made magnitude estimates of changes in the appearances of identical reflectances. Second, an author painted a watercolor of the 3-D Mondrians. The watercolor's reflectances quantified the changes in appearances. While constancy generalizations about illumination and reflectance hold for flat Mondrians, they do not for 3-D Mondrians. A constant paint does not exhibit perfect color constancy, but rather shows significant shifts in lightness, hue and chroma in response to the structure in the nonuniform illumination. Color appearance depends on the spatial information in both the illumination and the reflectances of objects. The spatial information of the quanta catch from the array of retinal receptors generates sensations that have variable correlation with surface reflectance. Models of appearance in humans need to calculate the departures from perfect constancy measured here. This article provides a dataset of measurements of color appearances for computational models of sensation. PMID:24478738

  18. Reflectance, illumination, and appearance in color constancy

    Directory of Open Access Journals (Sweden)

    John J. McCann


    Full Text Available We studied color constancy using a pair of identical 3-D Color Mondrian displays. We viewed one 3-D Mondrian in nearly uniform illumination, and the other in directional, nonuniform illumination. We used the three dimensional structures to modulate the light falling on the painted surfaces. The 3-D structures in the displays were a matching set of wooden blocks. Across Mondrian displays, each corresponding facet had the same paint on its surface. We used only 6 chromatic, and 5 achromatic paints applied to 104 block facets. The 3-D blocks add shadows and multiple reflections not found in flat Mondrians. Both 3-D Mondrians were viewed simultaneously, side-by-side. We used two techniques to measure correlation of appearance with surface reflectance. First, observers made magnitude estimates of changes in the appearances of identical reflectances. Second, an author painted a watercolor of the 3-D Mondrians. The watercolor’s reflectances quantified the changes in appearances. While constancy generalizations about illumination and reflectance hold for flat Mondrians, they do not for 3-D Mondrians. A constant paint does not exhibit perfect color constancy, but rather shows significant shifts in lightness, hue and chroma in response to the structure in the nonuniform illumination. Color appearance depends on the spatial information in both the illumination and the reflectances of objects. The spatial information of the quanta catch from the array of retinal receptors generates sensations that have variable correlation with surface reflectance. Models of appearance in humans need to calculate the departures from perfect constancy measured here. This article provides a dataset of measurements of color appearances for computational models of sensation.

  19. Reflectance, illumination, and appearance in color constancy. (United States)

    McCann, John J; Parraman, Carinna; Rizzi, Alessandro


    We studied color constancy using a pair of identical 3-D Color Mondrian displays. We viewed one 3-D Mondrian in nearly uniform illumination, and the other in directional, nonuniform illumination. We used the three dimensional structures to modulate the light falling on the painted surfaces. The 3-D structures in the displays were a matching set of wooden blocks. Across Mondrian displays, each corresponding facet had the same paint on its surface. We used only 6 chromatic, and 5 achromatic paints applied to 104 block facets. The 3-D blocks add shadows and multiple reflections not found in flat Mondrians. Both 3-D Mondrians were viewed simultaneously, side-by-side. We used two techniques to measure correlation of appearance with surface reflectance. First, observers made magnitude estimates of changes in the appearances of identical reflectances. Second, an author painted a watercolor of the 3-D Mondrians. The watercolor's reflectances quantified the changes in appearances. While constancy generalizations about illumination and reflectance hold for flat Mondrians, they do not for 3-D Mondrians. A constant paint does not exhibit perfect color constancy, but rather shows significant shifts in lightness, hue and chroma in response to the structure in the nonuniform illumination. Color appearance depends on the spatial information in both the illumination and the reflectances of objects. The spatial information of the quanta catch from the array of retinal receptors generates sensations that have variable correlation with surface reflectance. Models of appearance in humans need to calculate the departures from perfect constancy measured here. This article provides a dataset of measurements of color appearances for computational models of sensation.

  20. Random regression models

    African Journals Online (AJOL)


    modelled as a quadratic regression, nested within parity. The previous lactation length was ... This proportion was mainly covered by linear and quadratic coefficients. Results suggest that RRM could .... The multiple trait models in scalar notation are presented by equations (1, 2), while equation. (3) represents the random ...

  1. Randomized response methods

    NARCIS (Netherlands)

    van der Heijden, P.G.M.; Cruyff, Maarten; Bockenholt, U.


    In survey research it is often problematic to ask people sensitive questions because they may refuse to answer or they may provide a socially desirable answer that does not reveal their true status on the sensitive question. To solve this problem Warner (1965) proposed randomized response (RR). Here

  2. Random eigenvalue problems revisited

    Indian Academy of Sciences (India)

    The description of real-life engineering structural systems is associated with some amount of uncertainty in specifying material properties, geometric parameters, boundary conditions and applied loads. In the context of structural dynamics it is necessary to consider random eigenvalue problems in order to account for these ...

  3. absolutely regular random sequences

    Directory of Open Access Journals (Sweden)

    Michel Harel


    Full Text Available In this paper, the central limit theorems for the density estimator and for the integrated square error are proved for the case when the underlying sequence of random variables is nonstationary. Applications to Markov processes and ARMA processes are provided.

  4. A random matrix analysis

    Indian Academy of Sciences (India)

    chaos to galaxies. We demonstrate the applicability of random matrix theory for networks by pro- viding a new dimension to complex systems research. We show that in spite of huge differences ... as mentioned earlier, different types of networks can be constructed based on the nature of connections. For example,.

  5. Random eigenvalue problems revisited

    Indian Academy of Sciences (India)

    Several studies have been conducted on this topic since the mid-sixties. The. A list of .... Random eigenvalue problems revisited. 297 and various elements of Hij ,i ≤ j are statistically independent and Gaussian. The pdf of H can be expressed as, ...... Generality of this result however remains to be verified in future studies.

  6. On Randomness and Probability

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 2. On Randomness and Probability How to Mathematically Model Uncertain Events ... Author Affiliations. Rajeeva L Karandikar1. Statistics and Mathematics Unit, Indian Statistical Institute, 7 S J S Sansanwal Marg, New Delhi 110 016, India.

  7. Alzheimer random walk (United States)

    Odagaki, Takashi; Kasuya, Keisuke


    Using the Monte Carlo simulation, we investigate a memory-impaired self-avoiding walk on a square lattice in which a random walker marks each of sites visited with a given probability p and makes a random walk avoiding the marked sites. Namely, p = 0 and p = 1 correspond to the simple random walk and the self-avoiding walk, respectively. When p> 0, there is a finite probability that the walker is trapped. We show that the trap time distribution can well be fitted by Stacy's Weibull distribution b(a/b){a+1}/{b}[Γ({a+1}/{b})]-1x^a\\exp(-a/bx^b)} where a and b are fitting parameters depending on p. We also find that the mean trap time diverges at p = 0 as p- α with α = 1.89. In order to produce sufficient number of long walks, we exploit the pivot algorithm and obtain the mean square displacement and its Flory exponent ν(p) as functions of p. We find that the exponent determined for 1000 step walks interpolates both limits ν(0) for the simple random walk and ν(1) for the self-avoiding walk as [ ν(p) - ν(0) ] / [ ν(1) - ν(0) ] = pβ with β = 0.388 when p ≪ 0.1 and β = 0.0822 when p ≫ 0.1. Contribution to the Topical Issue "Continuous Time Random Walk Still Trendy: Fifty-year History, Current State and Outlook", edited by Ryszard Kutner and Jaume Masoliver.

  8. National Assessment of Oil and Gas Project - Uinta-Piceance Province (020) Maturation Contours (United States)

    U.S. Geological Survey, Department of the Interior — The maturation contours show vitrinite reflectance trends and ranges for five key petroleum system horizons within the Uinta-Piceance Province. The horizons are the...

  9. ARTc: Anisotropic reflectivity and transmissivity calculator (United States)

    Malehmir, Reza; Schmitt, Douglas R.


    While seismic anisotropy is known to exist within the Earth's crust and even deeper, isotropic or even highly symmetric elastic anisotropic assumptions for seismic imaging is an over-simplification which may create artifacts in the image, target mis-positioning and hence flawed interpretation. In this paper, we have developed the ARTc algorithm to solve reflectivity, transmissivity as well as velocity and particle polarization in the most general case of elastic anisotropy. This algorithm is able to provide reflectivity solution from the boundary between two anisotropic slabs with arbitrary symmetry and orientation up to triclinic. To achieve this, the algorithm solves full elastic wave equation to find polarization, slowness and amplitude of all six wave-modes generated from the incident plane-wave and welded interface. In the first step to calculate the reflectivity, the algorithm solves properties of the incident wave such as particle polarization and slowness. After calculation of the direction of generated waves, the algorithm solves their respective slowness and particle polarization. With this information, the algorithm then solves a system of equations incorporating the imposed boundary conditions to arrive at the scattered wave amplitudes, and thus reflectivity and transmissivity. Reflectivity results as well as slowness and polarization are then tested in complex computational anisotropic models to ensure their accuracy and reliability. ARTc is coded in MATLAB ® and bundled with an interactive GUI and bash script to run on single or multi-processor computers.

  10. Low reflectance high power RF load

    Energy Technology Data Exchange (ETDEWEB)

    Ives, R. Lawrence; Mizuhara, Yosuke M.


    A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.

  11. Metaphor-reflection in my healthcare experience

    Directory of Open Access Journals (Sweden)



    Full Text Available By exploring personal narratives through metaphoric images, students and nurses increase their understanding of who they are as persons and how that self-knowledge impacts their professional relationships with those in their care. In this article I share how I use metaphor-reflection in various aspects of my healthcare involvement. As a patient many years ago, metaphors helped me apprehend the meaning of cancer in my life. Today, as a nurse-teacher and researcher, I guide students through professional self-discovery using narrative reflective process that incorporates metaphors. In clinical practice I work with nurses as they explore how narrative reflection informs their caregiver-carereceiver interactions. With expanded self-awareness nurses have the potential to further assist their patients in exploring the meaning of their illness events through metaphors, thus enhancing the integration of that traumatic event into their respective lives. By working reflectively with metaphoric images, my hope for this writing is that my own engagement in narrative metaphor-reflection encourages the readers to story their own world in a more meaningful way.

  12. Cognitive Reflection Versus Calculation in Decision Making

    Directory of Open Access Journals (Sweden)

    Aleksandr eSinayev


    Full Text Available Scores on the three-item Cognitive Reflection Test (CRT have been linked with dual-system theory and normative decision making (Frederick, 2005. In particular, the CRT is thought to measure monitoring of System 1 intuitions such that, if cognitive reflection is high enough, intuitive errors will be detected and the problem will be solved. However, CRT items also require numeric ability to be answered correctly and it is unclear how much numeric ability vs. cognitive reflection contributes to better decision making. In two studies, CRT responses were used to calculate Cognitive Reflection and numeric ability; a numeracy scale was also administered. Numeric ability, measured on the CRT or the numeracy scale, accounted for the CRT’s ability to predict more normative decisions (a subscale of decision-making competence, incentivized measures of impatient and risk-averse choice, and self-reported financial outcomes; Cognitive Reflection contributed no independent predictive power. Results were similar whether the two abilities were modeled (Study 1 or calculated using proportions (Studies 1 and 2. These findings demonstrate numeric ability as a robust predictor of superior decision making across multiple tasks and outcomes. They also indicate that correlations of decision performance with the CRT are insufficient evidence to implicate overriding intuitions in the decision-making biases and outcomes we examined. Numeric ability appears to be the key mechanism instead.

  13. Improving reflectance reconstruction from tristimulus values by adaptively combining colorimetric and reflectance similarities (United States)

    Cao, Bin; Liao, Ningfang; Li, Yasheng; Cheng, Haobo


    The use of spectral reflectance as fundamental color information finds application in diverse fields related to imaging. Many approaches use training sets to train the algorithm used for color classification. In this context, we note that the modification of training sets obviously impacts the accuracy of reflectance reconstruction based on classical reflectance reconstruction methods. Different modifying criteria are not always consistent with each other, since they have different emphases; spectral reflectance similarity focuses on the deviation of reconstructed reflectance, whereas colorimetric similarity emphasizes human perception. We present a method to improve the accuracy of the reconstructed spectral reflectance by adaptively combining colorimetric and spectral reflectance similarities. The different exponential factors of the weighting coefficients were investigated. The spectral reflectance reconstructed by the proposed method exhibits considerable improvements in terms of the root-mean-square error and goodness-of-fit coefficient of the spectral reflectance errors as well as color differences under different illuminants. Our method is applicable to diverse areas such as textiles, printing, art, and other industries.

  14. Guided randomness in optimization

    CERN Document Server

    Clerc, Maurice


    The performance of an algorithm used depends on the GNA. This book focuses on the comparison of optimizers, it defines a stress-outcome approach which can be derived all the classic criteria (median, average, etc.) and other more sophisticated.   Source-codes used for the examples are also presented, this allows a reflection on the ""superfluous chance,"" succinctly explaining why and how the stochastic aspect of optimization could be avoided in some cases.

  15. Reflective learning in higher education: Application to clinical nursing

    African Journals Online (AJOL)

    A qualitative, non-empirical study was conducted to develop a model for educating reflective neonatal nurses in a South African context. Phase 1 of ... The concepts 'reflection', 'reflective learning', 'reflective thinking' and 'reflective reasoning' were clarified through a process of data exploration and analysis. A definition of ...

  16. Self-Reflection and Academic Performance: Is There a Relationship? (United States)

    Lew, Magdeleine D. N.; Schmidt, Henk G.


    The purposes of the present study were two-fold: first, to evaluate whether reflection journal writing was effective in promoting self-reflection and learning, and whether students become better at self-reflection if they engage continuously in reflection journal writing. To that end, the reflection journals of 690 first-year applied science…

  17. About the use of reflectance terminology in imaging spectroscopy


    Schaepman-Strub, G.; Schaepman, M.E.; Dangel, S.; Painter, T.; Martonchik, J.


    Analysing databases, field and airborne spectrometer data, modelling studies and publications, a lack of consistency in the use of definitions and terminology of reflectance quantities can be observed. One example is the term `BRDF¿ (bidirectional reflectance distribution function) assigned to significantly differing quantities, ranging from the bidirectional reflectance distribution function to hemispherical-conical reflectance factors. Our contribution summarizes basic reflectance nomenclat...

  18. Characterizing the monaural and binaural processes underlying reflection masking

    DEFF Research Database (Denmark)

    Buchholz, Jörg


    Reflection masked thresholds (RMTs) for the simple scenario of a test reflection masked by the direct sound (200 ms long broadband noise) were measured as a function of reflection delay for diotic and dichotic stimulus presentations. In order to discriminate between contributions to reflection....... The monaural and binaural processes that may underlie reflection masking are discussed in terms of auditory-modelling concepts....

  19. Reflectivity level of radio anechoic chambers

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen


    A comparison between the antenna-pattern comparison technique and the free-space voltage standing-wave ratio technique for evaluating the reflectivity level of radio anechoic chambers is presented. Based on an analysis of the two techniques, it is pointed out which parameters influence the measured...... be used to measure the improvements. This work is inspired by the current discussion of finding a figure of merit for anechoic chambers. Based on the results, an evaluation procedure for anechoic chambers is indicated. However, it is pointed out and illustrated by examples that further investigations...... value of the reflectivity level. The comparison is illustrated with experimental results and it is explained why inconsistent and uncorrelated results may be found when the two methods are used. Furthermore, it is demonstrated, by introducing improvements in a chamber, how the reflectivity level can...

  20. Soil Moisture Monitorization Using GNSS Reflected Signals

    CERN Document Server

    Egido, Alejandro; Caparrini, Marco; Martin, Cristina; Farres, Esteve; Banque, Xavier


    The use of GNSS signals as a source of opportunity for remote sensing applications, GNSS-R, has been a research area of interest for more than a decade. One of the possible applications of this technique is soil moisture monitoring. The retrieval of soil moisture with GNSS-R systems is based on the variability of the ground dielectric properties associated to soil moisture. Higher concentrations of water in the soil yield a higher dielectric constant and reflectivity, which incurs in signals that reflect from the Earth surface with higher peak power. Previous investigations have demonstrated the capability of GPS bistatic scatterometers to obtain high enough signal to noise ratios in order to sense small changes in surface reflectivity. Furthermore, these systems present some advantages with respect to others currently used to retrieve soil moisture. Upcoming satellite navigation systems, such as the European Galileo, will represent an excellent source of opportunity for soil moisture remote sensing for vario...

  1. Reflective article having a sacrificial cathodic layer (United States)

    Kabagambe, Benjamin; Buchanan, Michael J.; Scott, Matthew S.; Rearick, Brian K.; Medwick, Paul A.; McCamy, James W.


    The present invention relates to reflective articles, such as solar mirrors, that include a sacrificial cathodic layer. The reflective article, more particularly includes a substrate, such as glass, having a multi-layered coating thereon that includes a lead-free sacrificial cathodic layer. The sacrificial cathodic layer includes at least one transition metal, such as a particulate transition metal, which can be in the form of flakes (e.g., zinc flakes). The sacrificial cathodic layer can include an inorganic matrix formed from one or more organo-titanates. Alternatively, the sacrificial cathodic layer can include an organic polymer matrix (e.g., a crosslinked organic polymer matrix formed from an organic polymer and an aminoplast crosslinking agent). The reflective article also includes an outer organic polymer coating, that can be electrodeposited over the sacrificial cathodic layer.

  2. Investigating murals with terahertz reflective tomography (United States)

    Yuan, Minjie; Sun, Wenfeng; Wang, Xinke; Wang, Sen; Zhang, Qunxi; Ye, Jiasheng; Zhang, Yan


    Terahertz time-domain spectroscopy (THz-TDS) imaging technology has been proposed to be used in the non-invasive detection of murals. THz-TDS images provide structural data of the sample that cannot be obtained with other complementary techniques. In this paper, two types of defects hidden in the plaster used to simulate the cases of defects in the murals, have been investigated by the terahertz reflected time domain spectroscopy imaging system. These preset defects include a leaf slice and a slit built in the plaster. With the terahertz reflective tomography, information about defects has been determined involving the thickness from the surface of sample to the built-in defect, the profile and distribution of the defect. With this THz tomography, different defects with the changes of optical thickness and their relative refractive index have been identified. The application of reflective pulsed terahertz imaging has been extended to the defect detection of the murals.

  3. A Declarative Approach to Architectural Reflection

    DEFF Research Database (Denmark)

    Ingstrup, Mads; Hansen, Klaus Marius


    which both creates runtime models of specific distributed architectures and allow for evaluation of AQL queries on these models. We illustrate the viability of the approach in two particular applications of such a model: constraint checking relative to an architectural style, and reasoning about certain......Recent research shows runtime architectural reflection is instrumental in, for instance, building adaptive and flexible systems or checking correspondence between design and implementation. Moreover, experience with computational reflection in various branches of computer science shows...... that the interface through which the meta-information of the running system is accessed, and possibly modified, lies at the heart of designing reflective systems. This paper proposes that such an interface should be like a database: accessed through queries expressed using the concepts with which architecture...

  4. X-ray induced optical reflectivity

    Directory of Open Access Journals (Sweden)

    Stephen M. Durbin


    Full Text Available The change in optical reflectivity induced by intense x-ray pulses can now be used to study ultrafast many body responses in solids in the femtosecond time domain. X-ray absorption creates photoelectrons and core level holes subsequently filled by Auger or fluorescence processes, and these excitations ultimately add conduction and valence band carriers that perturb optical reflectivity. Optical absorption associated with band filling and band gap narrowing is shown to explain the basic features found in recent measurements on an insulator (silicon nitride, Si3N4, a semiconductor (gallium arsenide, GaAs, and a metal (gold, Au, obtained with ∼100 fs x-ray pulses at 500-2000 eV and probed with 800 nm laser pulses. In particular GaAs exhibits an abrupt drop in reflectivity, persisting only for a time comparable to the x-ray excitation pulse duration, consistent with prompt band gap narrowing.

  5. Reflectivity-modulated grating-mirror

    DEFF Research Database (Denmark)


    The invention relates to vertical cavity lasers (VCL) incorporating a reflectivity-modulated grating mirror (1) for modulating the laser output. A cavity is formed by a bottom mirror (4), an active region (3), and an outcoupling top grating mirror (1) formed by a periodic refractive index grating...... region in a layer structure comprising a p- and a n-doped semiconductor layer with an electrooptic material layer (12) arranged there between. The grating region comprises a grating structure formed by periodic perforations to change the refractive index periodically in directions normal...... to the oscillation axis. A modulated voltage (91) is applied in reverse bias between the n- and p-doped layers to modulate the refractive index of the electrooptic material layer (12) and thereby the reflectivity spectrum of the grating mirror (1). The reflectivity of the grating mirror (1) can be modulated between...

  6. Mitigation of surface reflection in PIV measurements (United States)

    Paterna, E.; Moonen, P.; Dorer, V.; Carmeliet, J.


    Surface reflections of high-intensity laser light are a common concern when conducting particle image velocimetry (PIV) measurements. Consequences range from a poor signal-to-noise ratio (overexposure) in near-surface areas up to camera sensor damage. The severity depends on the interplay between three factors: surface properties, laser light intensity and relative camera position. In stereoscopic or tomographic PIV setups, material selection is often the only factor which can be adapted. We present a systematic comparative study, involving different materials and surface treatments. Their potential to mitigate surface reflections is quantified against the reference case of a flat black painted wooden surface. The largest reduction of surface reflection intensity is obtained by applying fluorescent paint on wood or by employing electropolished steel. The more widely used flat black painted wood shows poor behavior.

  7. Total internal reflection fluorescence (TIRF) microscopy. (United States)

    Trache, Andreea; Meininger, Gerald A


    Total internal reflection fluorescence (TIRF) microscopy represents a method of exciting and visualizing fluorophores present in the near-membrane region of live or fixed cells grown on coverslips. TIRF microscopy is based on the total internal reflection phenomenon that occurs when light passes from a high-refractive medium (e.g., glass) into a low-refractive medium (e.g., cell, water). The evanescent field produced by total internally reflected light excites the fluorescent molecules at the cell-substrate interface and is accompanied by minimal exposure of the remaining cell volume. This technique provides high-contrast fluorescence images, with very low background and virtually no out-of-focus light, ideal for visualization and spectroscopy of single-molecule fluorescence near a surface. This unit presents, in a concise manner, the principle of operation, instrument diversity, and TIRF microscopy applications for the study of biological samples. Copyright 2008 by John Wiley & Sons, Inc.

  8. Theory of relativistic radiation reflection from plasmas (United States)

    Gonoskov, Arkady


    We consider the reflection of relativistically strong radiation from plasma and identify the physical origin of the electrons' tendency to form a thin sheet, which maintains its localisation throughout its motion. Thereby, we justify the principle of relativistic electronic spring (RES) proposed in [Gonoskov et al., Phys. Rev. E 84, 046403 (2011)]. Using the RES principle, we derive a closed set of differential equations that describe the reflection of radiation with arbitrary variation of polarization and intensity from plasma with an arbitrary density profile for an arbitrary angle of incidence. We confirm with ab initio PIC simulations that the developed theory accurately describes laser-plasma interactions in the regime where the reflection of relativistically strong radiation is accompanied by significant, repeated relocation of plasma electrons. In particular, the theory can be applied for the studies of plasma heating and coherent and incoherent emissions in the RES regime of high-intensity laser-plasma interaction.

  9. Random vibrations theory and practice

    CERN Document Server

    Wirsching, Paul H; Ortiz, Keith


    Random Vibrations: Theory and Practice covers the theory and analysis of mechanical and structural systems undergoing random oscillations due to any number of phenomena— from engine noise, turbulent flow, and acoustic noise to wind, ocean waves, earthquakes, and rough pavement. For systems operating in such environments, a random vibration analysis is essential to the safety and reliability of the system. By far the most comprehensive text available on random vibrations, Random Vibrations: Theory and Practice is designed for readers who are new to the subject as well as those who are familiar with the fundamentals and wish to study a particular topic or use the text as an authoritative reference. It is divided into three major sections: fundamental background, random vibration development and applications to design, and random signal analysis. Introductory chapters cover topics in probability, statistics, and random processes that prepare the reader for the development of the theory of random vibrations a...

  10. The playful and reflective game designer

    DEFF Research Database (Denmark)

    Majgaard, Gunver


    be considered to be a sandbox where experimentation was a motivational factor for the students, as they could make mistakes and try out creative ideas. Although the constructionistic learning approach promoted creative and innovative learning, it did not develop competencies in articulation and analysis....... The aim was for students to reflect on games in order to promote explicit knowledge. Based on the theory, we consider retrospective reflective discussions in the classroom and their programming experiences reinforced the learning process. In summary, we present the students' first progression from native...

  11. Liquid Carbon Reflectivity at 19 nm

    Directory of Open Access Journals (Sweden)

    Riccardo Mincigrucci


    Full Text Available We hereby report on a pump-probe reflectivity experiment conducted on amorphous carbon, using a 780 nm laser as a pump and a 19 nm FEL emission as probe. Measurements were performed at 50 degrees with respect to the surface normal to have an un-pumped reflectivity higher than 0.5%. A sub-10 fs time synchronization error could be obtained exploiting the nearly jitter-free capabilities of FERMI. EUV FEL-based experiments open the way to study the behaviour of a liquid carbon phase being unaffected by plasma screening.

  12. Water Pollution Detection by Reflectance Measurements (United States)

    Goolsby, A. D.


    Measurement of the intensity of light reflected from various planar liquid surfaces has been performed. The results of this brief study show that the presence of a film of foreign material floating on a reference substrate is easily detected by reflectance measurement if the two liquids possess significantly different refractive indices, for example, oil (n = 1.40) and water (n = 1.33). Additional study of various optical configurations, and the building and testing of a prototype monitoring device revealed that the method is sufficiently practical for application to continuous water quality monitoring.

  13. Gravitational wave sources: reflections and echoes (United States)

    Price, Richard H.; Khanna, Gaurav


    The recent detection of gravitational waves has generated interest in alternatives to the black hole interpretation of sources. A subset of such alternatives involves a prediction of gravitational wave ‘echoes’. We consider two aspects of possible echoes: first, general features of echoes coming from spacetime reflecting conditions. We find that the detailed nature of such echoes does not bear any clear relationship to quasi-normal frequencies. Second, we point out the pitfalls in the analysis of local reflecting ‘walls’ near the horizon of rapidly rotating black holes.

  14. Bioinspired irregularly chirped broadband reflecting multilayers (United States)

    Chiadini, Francesco; Fiumara, Vincenzo; Scaglione, Antonio


    Dielectric multilayers consisting of alternating layers of two different materials with thicknesses irregularly decreasing with depth in the structure are included in the cuticle of some beetles whose shell exhibits broadband reflection in the optical wavelength range. Emulating these structures, we propose and numerically analyze irregularly chirped dielectric multilayers. Analysis was performed using a dedicated genetic algorithm (GA) that searches for the multilayer configurations maximizing the reflection for normal incidence over a large wavelength range. We found that the GA leads to the irregularly chirped reflectors that significantly outperform the regularly chirped ones proposed and analyzed in the literature.

  15. Temporal processes involved in simultaneous reflection masking

    DEFF Research Database (Denmark)

    Buchholz, Jörg


    reflection delays and enhances the test reflection for large delays. Employing a 200-ms-long broadband noise burst as input signal, the critical delay separating these two binaural phenomena was found to be 7–10 ms. It was suggested that the critical delay refers to a temporal window that is employed......, resulting in a critical delay of about 2–3 ms for 20-ms-long stimuli. Hence, for very short stimuli the temporal window or critical delay exhibits values similar to the auditory temporal resolution as, for instance, observed in gap-detection tasks. It is suggested that the larger critical delay observed...

  16. Generalization as creative and reflective act

    DEFF Research Database (Denmark)

    Tateo, Luca


    It is argued that generalization in psychology is a creative, interpretative, and reflective act of thought, by accessing a higher level of abstraction from meaningful events. In the context of clarification of this claim, a fresh look at Lewin’s argumentation about the “Aristotelian” and “Galile......It is argued that generalization in psychology is a creative, interpretative, and reflective act of thought, by accessing a higher level of abstraction from meaningful events. In the context of clarification of this claim, a fresh look at Lewin’s argumentation about the “Aristotelian...

  17. Enhanced reflection from inverse tapered nanocone arrays

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Xiang-Tian; Dai, Qing, E-mail: [National Center for Nanoscience and Technology, Beijing 100190 (China); Butt, Haider, E-mail:; Deng, Sunan [School of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Yetisen, Ali K.; Cruz Vasconcellos, Fernando da [Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT (United Kingdom); Kangwanwatana, Chuan; Montelongo, Yunuen; Qasim, Malik M.; Wilkinson, Timothy D. [Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom)


    We computationally and experimentally demonstrate enhanced reflection effects displayed by silicon-based inverted nanocone arrays. A 3D finite element model is used to characterize the optical properties of the nanocone arrays with respect to the change in polarization and incident angles. The nanocone arrays are fabricated by e-beam lithography in hexagonal and triangular geometries with a lattice constant of 300 nm. The fabricated devices show a two-fold increase in reflection compared with bare silicon surface, as well as a strong diffraction within the visible and near-infrared spectra. The nanocone arrays may find a variety of applications from optical devices to energy conservation technologies.

  18. Use of reflective surfaces on roadway embankment

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr; Doré, Guy


    Temperature measurements have been used to study the effect of two reflective surfaces on a roadway embankment in Forêt Montmorency, Québec, Canada. Both tested materials, Mapelastic (from MAPEI) and Colored Slurry (from Tech-Mix), have lead to a reduction in n-factor and proved to have very good...... adherence characteristics for roadway use. In Kangerlussuaq Airport, western Greenland, ground-penetrating radar (GPR) has been used to compare the variation of the frost table underneath a normal black asphalt surface and a more reflective surface (white paint). The GPR results have shown a clear...

  19. Afro-descendant Trajectories: A Methodological Reflection

    Directory of Open Access Journals (Sweden)

    Manuel Matos Díaz


    Full Text Available This article offers a reflection about how we think of Afro-descendant people as objectsor subjects of study. To do this, it reflects on the question: How does the study of Afrodescendantpeoples change when the so-called “unit of analysis” is not a slave, but anenslaved ancestor who is part of your contemporary cosmology? The way of arriving atthis question, and the analysis presented henceforth attempts to highlight key aspects foradvancing Afro-descendant scholarship: specifically the role of black feminist thought andpractices on ancestral consciousness; and its subsequent impact on the interpretation andproduction of historical and socio-political sources.

  20. Two-dimensional simulation of quantum reflection (United States)

    Galiffi, Emanuele; Sünderhauf, Christoph; DeKieviet, Maarten; Wimberger, Sandro


    A propagation method for the scattering of a quantum wave packet from a potential surface is presented. It is used to model the quantum reflection of single atoms from a corrugated (metallic) surface. Our numerical procedure works well in two spatial dimensions requiring only reasonable amounts of memory and computing time. The effects of the surface corrugation on the reflectivity are investigated via simulations with a paradigm potential. These indicate that our approach should allow for future tests of realistic, effective potentials obtained from theory in a quantitative comparison to experimental data.

  1. Lunar surface reflectance by LALT aboard KAGUYA (United States)

    Noda, H.; Araki, H.; Ishihara, Y.; Tazawa, S.; Sasaki, S.; Kawano, N.


    The Laser Altimeter (LALT) aboard Japanese lunar explorer KAGUYA (SELENE) is a ranging instrument which measures the distance between the satellite and the lunar surface with accuracy of 1 m by detecting the timing delay of the reflected laser light. The main science goal of the LALT is to obtain the lunar global topographic data including polar regions for the study of the origin and the evolution of the Moon [1]. Besides, the LALT is equipped with an intensity monitor of the returned pulses. The intensity of the returned pulses contains information concerning surface roughness and reflectance of the footprints, which will contribute to the study of the lunar surface maturity and age. The reflectance at LALT wavelength (1064nm) is sensitive to the surface maturity and composition. The data should be particularly important at lunar polar regions where camera instruments should suffer from phase angle effects in the surface reflectance and moreover cannot obtain reflectance data at the permanently shadowed area. The normal operation of the LALT began on 30th, December 2007 after two months’ commissioning phase. Before the end of the normal operation phase in October 2008, the LALT measured more than 10 million range data. Unfortunately, due to the laser power decrease and also possible smaller surface reflectance than the expected value before launch (15 % at 1 micro meter), the return pulse intensity during the nominal mission phase is so small that they are not reliable enough to discuss the surface property. During the extended mission phase, which started November 2008, the satellite altitude decreased to 50 km. Due to the malfunction of the reaction wheel and high-voltage instruments were shutdown, the observation was suspended until 11th of February, 2009. LALT successfully resumed observation on 12th February and continued observation until the controlled crash of KAGUYA onto the Moon on 10th of June, 2009. Thanks to the lower orbit during this phase, the

  2. Reflections on the Design of Exertion Games. (United States)

    Mueller, Florian Floyd; Altimira, David; Khot, Rohit Ashot


    The design of exertion games (i.e., digital games that require physical effort from players) is a difficult intertwined challenge of combining digital games and physical effort. To aid designers in facing this challenge, we describe our experiences of designing exertion games. We outline personal reflections on our design processes and articulate analyses of players' experiences. These reflections and analyses serve to highlight the unique opportunities of combining digital games and physical effort. The insights we seek aim to enhance the understanding of exertion game design, contributing to the advancement of the field, and ultimately resulting in better games and associated player experiences.

  3. Radar reflection off extensive air showers

    Directory of Open Access Journals (Sweden)

    Werner F.


    Full Text Available We investigate the possibility of detecting extensive air showers by the radar technique. Considering a bistatic radar system and different shower geometries, we simulate reflection of radio waves off the static plasma produced by the shower in the air. Using the Thomson cross-section for radio wave reflection, we obtain the time evolution of the signal received by the antennas. The frequency upshift of the radar echo and the power received are studied to verify the feasibility of the radar detection technique.

  4. The Effect of Field Spectral Reflectance Measurement Distance to the Spectral Reflectance of Rhizophora stylosa (United States)

    Kamal, M.; Ningam, M. U. L.; Alqorina, F.


    Mapping mangrove species from remote sensing data through its spectral reflectance pattern collected in the field is challenging. There are high variations in light condition, leaf orientation, canopy structure, background objects and measurement distance when measuring mangrove spectral reflectance in the field. Spectral measurement distance to the object is one of the most important aspects controlling the result of spectral reflectance pattern. This research is aimed to assess the effect of spectral reflectance pattern of Rhizophora stylosa collected at various distances. Specific objectives of this research are to collect samples of mangrove spectral reflectance pattern in the field, to assess the effect of the observation scale to the result of the spectral reflectance pattern, and to characterize the mangrove spectral reflectance pattern resulted from different observation scales. Spectral reflectance data collection in the field was conducted using JAZ EL-350 field spectrometer at 2cm, 50cm, 1m, 2m, and 5m distance and was conducted in Karimunjawa Island, Jepara, Central Java, Indonesia. A visual comparison of the spectral reflectance curve was conducted to understand the effect of measurement distance. The results of this study indicate that the difference in the measurement distance of Rhizophora stylosa species was highly influential to the resulting spectral reflectance curve. The spectral reflectance curve recorded at close range to the leaf (i.e. 2 cm) has the lowest curve variation, as well as the furthest distance (i.e. 5 m). This study is a basic study that supports the development of the use of remote sensing imagery for mangrove species mapping.

  5. Random Raman lasing

    CERN Document Server

    Hokr, Brett H; Mason, John D; Beier, Hope T; Rockwll, Benjamin A; Thomas, Robert J; Noojin, Gary D; Petrov, Georgi I; Golovan, Leonid A; Yakovlev, Vladislav V


    Propagation of light in a highly scattering medium is among the most fascinating optical effect that everyone experiences on an everyday basis and possesses a number of fundamental problems which have yet to be solved. Conventional wisdom suggests that non-linear effects do not play a significant role because the diffusive nature of scattering acts to spread the intensity, dramatically weakening these effects. We demonstrate the first experimental evidence of lasing on a Raman transition in a bulk three-dimensional random media. From a practical standpoint, Raman transitions allow for spectroscopic analysis of the chemical makeup of the sample. A random Raman laser could serve as a bright Raman source allowing for remote, chemically specific, identification of powders and aerosols. Fundamentally, the first demonstration of this new light source opens up an entire new field of study into non-linear light propagation in turbid media, with the most notable application related to non-invasive biomedical imaging.

  6. On fairness and randomness

    DEFF Research Database (Denmark)

    Jaeger, Manfred


    We investigate the relation between the behavior of non-deterministic systems under fairness constraints, and the behavior of probabilistic systems. To this end, first a framework based on computable stopping strategies is developed that provides a common foundation for describing both fair...... and probabilistic behavior. On the basis of stopping strategies it is then shown that fair behavior corresponds in a precise sense to random behavior in the sense of Martin-Löf's definition of randomness. We view probabilistic systems as concrete implementations of more abstract non-deterministic systems. Under...... this perspective the question is investigated what probabilistic properties are needed in such an implementation to guarantee (with probability one) certain required fairness properties in the behavior of the probabilistic system. Generalizing earlier concepts of ε -bounded transition probabilities, we introduce...

  7. Free random variables

    CERN Document Server

    Voiculescu, Dan; Nica, Alexandru


    This book presents the first comprehensive introduction to free probability theory, a highly noncommutative probability theory with independence based on free products instead of tensor products. Basic examples of this kind of theory are provided by convolution operators on free groups and by the asymptotic behavior of large Gaussian random matrices. The probabilistic approach to free products has led to a recent surge of new results on the von Neumann algebras of free groups. The book is ideally suited as a textbook for an advanced graduate course and could also provide material for a seminar. In addition to researchers and graduate students in mathematics, this book will be of interest to physicists and others who use random matrices.

  8. Intravaginal stimulation randomized trial. (United States)

    Smith, J J


    The effectiveness of intravaginal electrical stimulation was compared to standard therapy in the treatment of genuine stress urinary incontinence and detrusor instability. A total of 57 women with urinary incontinence was evaluated with video urodynamics and voiding diaries before and after treatment. Of the women 18 with stress urinary incontinence were randomized to electrical stimulation or Kegel exercise and 38 with detrusor instability were randomized to anticholinergic therapy or electrical stimulation. Of patients using electrical stimulation in the stress urinary incontinence group 66% improved and 72% of the patients with detrusor instability treated with electrical stimulation improved. These rates were not statistically significant when compared to traditional therapy. Electrical stimulation is safe and at least as effective as properly performed Kegel and anticholinergic therapy in the treatment of stress urinary incontinence and detrusor instability.

  9. Certified randomness in quantum physics. (United States)

    Acín, Antonio; Masanes, Lluis


    The concept of randomness plays an important part in many disciplines. On the one hand, the question of whether random processes exist is fundamental for our understanding of nature. On the other, randomness is a resource for cryptography, algorithms and simulations. Standard methods for generating randomness rely on assumptions about the devices that are often not valid in practice. However, quantum technologies enable new methods for generating certified randomness, based on the violation of Bell inequalities. These methods are referred to as device-independent because they do not rely on any modelling of the devices. Here we review efforts to design device-independent randomness generators and the associated challenges.

  10. Certified randomness in quantum physics (United States)

    Acín, Antonio; Masanes, Lluis


    The concept of randomness plays an important part in many disciplines. On the one hand, the question of whether random processes exist is fundamental for our understanding of nature. On the other, randomness is a resource for cryptography, algorithms and simulations. Standard methods for generating randomness rely on assumptions about the devices that are often not valid in practice. However, quantum technologies enable new methods for generating certified randomness, based on the violation of Bell inequalities. These methods are referred to as device-independent because they do not rely on any modelling of the devices. Here we review efforts to design device-independent randomness generators and the associated challenges.

  11. A reflective approach to HE language provision : integrating context and language through semistructured reflection

    NARCIS (Netherlands)

    Haines, Kevin; Ashworth - Kadwell, Angela; Wilkinson, Robert; Zegers, Vera


    Taking a sociocultural perspective to second language acquisition, this paper describes the implementation in an HE curriculum of an approach that encourages students to reflect on language learning in its wider context. Students are provided with tools for reflection through which they can make

  12. Reflection for Learning, Learning for Reflection: Developing Indigenous Competencies in Higher Education (United States)

    Bennett, Dawn; Power, Anne; Thomson, Chris; Mason, Bonita; Bartleet, Brydie-Leigh


    Reflection is an essential part of students' critically reflective development within experiential-learning contexts; it is arguably even more important when working cross-culturally. This paper reports from a national, arts-based service-learning project in which students in creative arts, media and journalism, and preservice teachers worked with…

  13. Towards a Theory of the Ecology of Reflection: Reflective Practice for Experiential Learning in Higher Education (United States)

    Harvey, Marina; Coulson, Debra; McMaugh, Anne


    Reflective practice is widely adopted across the field of experience-based learning subjects in higher education, including practicums, work-integrated learning, internships, service learning and community participation. This adoption of reflective practice implies that it supports student learning through experience. When reviewing the evidence…

  14. Automatic construction of probabilistic dynamic bidirectional reflectance distribution functions from reflection screen images (United States)

    Bailey, Albert; Early, Edward; Kennedy, Paul; Thomas, Robert


    The reflections of high energy laser off surfaces can present hazards to persons and instruments at significant distances. The heating from these lasers cause changes in the reflection characteristics of surfaces they impact. As such, the reflections from these surfaces cannot be properly modeled with static bidirectional reflectance distribution functions (BRDFs), but require time-dynamic BRDFs. Moreover, the time-evolution of the surface reflections is not deterministic, but can vary even when the materials and irradiance conditions are nearly identical, such that only probabilistic characterization is realistic. Due to the swiftly changing nature of the reflections, traditional BRDF measurements with goniometric instruments is impossible, and BRDFs must be deduced from images of the reflected light incident on a screen which intercepts a portion of the reflection solid angle. A model has been constructed to describe these complex probabilistic dynamic BRDFs with only a moderate number of intuitive parameters, where these parameters have central values and statistical variances. These simple parametric representations are appropriate for use in predictive modeling codes and are also easily adjustable to allow facile exploration of the sensitivity of hazards to laser, material, and model uncertainties. An automated procedure has been created for determining appropriate parameter values and variances from captured screen images, without the need for case-by-case human judgment. Examples of the parameter determination procedure are presented.

  15. In Two Minds: How Reflections Influence Software Architecture Design Thinking : how reflections influence software design thinking

    NARCIS (Netherlands)

    Razavian, Maryam; Tang, Anthony; Capilla, Rafael; Lago, Patricia


    We theorize a two-mind model of design thinking. Mind 1 is about logical design reasoning, and Mind 2 is about the reflection on our reasoning and judgments. The problem solving ability of Mind 1 has often been emphasized in software engineering. The reflective Mind 2, however, has not received much

  16. Combined EUV reflectance and X-ray reflectivity data analysis of periodic multilayer structures

    NARCIS (Netherlands)

    Yakunin, S. N.; Makhotkin, I. A.; K. V. Nikolaev,; van de Kruijs, R. W. E.; Chuev, M. A.; F. Bijkerk,


    We present a way to analyze the chemical composition of periodical multilayer structures using the simultaneous analysis of grazing incidence hard X-Ray reflectivity (GIXR) and normal incidence extreme ultraviolet reflectance (EUVR). This allows to combine the high sensitivity of GIXR data to layer

  17. Reflections around Artefacts: Using a Deliberative Approach to Teaching Reflective Practices in Fashion Studies (United States)

    Ryan, Michael; Brough, Dean


    While requiring students to think reflectively is a desirable teaching goal, it is often fraught with complexity and is sometimes poorly implemented in higher education. In this paper, we describe an approach to academic reflective practices that fitted a design subject in fashion education and was perceived as effective in enhancing student…

  18. Reflective journal writing: how it promotes reflective thinking in clinical nursing education: a students' perspective. (United States)

    Kok, J; Chabeli, M M


    According to the outcomes-based education and training system of education (OBET) in the country and the South African Nursing Council, education should focus on "creating" reflective learners and practitioners. This article seeks to determine the effectiveness of reflective journal writing in promoting the reflective thinking of learners in clinical nursing education and to validate the guidelines described in a bigger study on how to facilitate reflective thinking using reflective journal writing. A qualitative, contextual, explorative, descriptive research design was used to determine the learners' perceptions on whether reflective journal writing did promote their higher-level thinking skills during the six-month placement in a psychiatric clinical practice using the reflective diaries. From a population of seventeen fourth-year students, six volunteered to participate in a focus group interview. The data was analysed by means of the descriptive method of open coding of Tesch (in Creswell, 1994:154-156). Positive and negative results from the perceptions of the participants and a literature review served as a basis for deducing and describing guidelines for the effective use of reflective journal writing in promoting reflective thinking in clinical nursing education. The positive perception was the development of problem-solving skills attained through reflection by using analytical critical thinking, synthesis and the evaluation of situations. Self-evaluation leading to intellectual growth and self-awareness indicated a positive perception. Negative perceptions were that reflective journal writing is time consuming, content based with a lack of clear expectations from the teacher, and distrust of students about the information written. Guba's model of ensuring trustworthiness in qualitative research as described in Krefting (1991:215-222) was employed. It is concluded that reflective journal writing in clinical nursing education does promote reflective

  19. Reflecting on life, not on the mind – The concept of self-reflection without stability

    DEFF Research Database (Denmark)

    Jensen, Lasse Meinert

    with “stability”. When self-reflection is conceptualized as a second-order process charged with creating diachronic continuity in the person’s life, as it often is in both philosophy (Frankfurt, 1971), cognitive theory (Carver, Scheier & Fulton, 2008), and narrative theories of personality (McAdams, 2008......), “Stability” and how it is brought about, becomes the main concern. But presupposing “stability” as the main aim of self-reflection isolates reflection to a mental realm. Human beings are certainly self-conscious, but – following Dreier (1999), when he points out that reflection is not a distancing from......, but part of the person’s engagement with the world – I’ll focus on a theoretical conceptualization of reflection as an activity that persons carry out in the context of their life course. I’ll take up Schatzki’s notion of social order as an arrangement in which entities relate, occupy positions...

  20. Common-cavity ytterbium/Raman random distributed feedback fiber laser (United States)

    Wu, Han; Wang, Zinan; He, Qiheng; Sun, Wei; Rao, Yunjiang


    In this letter, a common-cavity random distributed feedback fiber laser which can generate both 1064 nm ytterbium-doped random lasing and 1115 nm ytterbium-Raman random lasing is proposed and experimentally demonstrated for the first time. The common cavity is based on the combination of the double-cladding ytterbium-doped fiber and the standard single mode fiber (SMF); a 1064 nm high-reflectivity fiber Bragg grating and the fiber flat-end are connected to the signal port of the pump combiner as the point reflectors. The generated 1064 nm random lasing can serve as the Raman pump in the SMF, thus 1115 nm random lasing could be stimulated with the hybrid ytterbium-Raman gain. The feedback for 1115 nm random lasing is the combination of flat-end fiber and random Rayleigh feedback. By controlling the value of flat-end fiber’s reflectivity to 0.002, stable 1.91 W of 1064 nm ytterbium-doped random lasing and 3.72 W of 1115 nm ytterbium-Raman random lasing are generated successively. This work could provide a simple and cost-effective way to generate high-power random lasing.

  1. The Role of Reflection in Sport Expertise

    NARCIS (Netherlands)

    Jonker, Laura; Elferink-Gemser, Marije T.; de Roos, Ilse M.; Visscher, Chris

    Reflection is considered a key factor in expert learning and refers to the extent to which individuals are able to appraise what they have learned and to integrate these experiences into future actions, thereby maximizing performance improvements. We assessed the relation between self-reported

  2. Reflection halo twins : subsun and supersun

    NARCIS (Netherlands)

    Konnen, Gunther P.; van der Werf, Siebren Y.


    From an aircraft, a short distinct vertical structure is sometimes seen above the setting sun. Such a feature can be understood as a halo, which is the counterpart of the well-known subsun. Whereas the latter arises from reflections off basal faces of plate-oriented ice crystals illuminated from

  3. The Art of Self-Reflection (United States)

    Villano, Matt


    Metaphysically speaking, the idea of self-reflection has been the subject of discussion for thousands of years. The idea carried human beings through the Renaissance, and an entire movement tied to it sparked a sociopolitical movement called the Enlightenment. In more recent times, thought leaders such as Immanuel Kant, Karl Marx, and Sigmund…

  4. Reflective self-awareness and conscious states

    DEFF Research Database (Denmark)

    Kjaer, Troels W; Nowak, Markus; Lou, Hans C


    A recent meta-analysis has shown precuneus, angular gyri, anterior cingulate gyri, and adjacent structures to be highly metabolically active in support of resting consciousness. We hypothesize that these regions constitute a functional network of reflective self-awareness thought to be a core fun...

  5. Reflection in psychoanalysis: on symbols and metaphors. (United States)

    Enckell, Henrik


    Psychoanalysis is an art of reflection, i.e. it tries to facilitate the subject's retrieval of his own self. The 'material' to be reflected upon consists of the products of human symbolization. But there are two views of reflection. In one, the self is searched in a temporal, structural and procedural 'anterior' (the model of archaeology). In the other the self is to be found in a still evolving meaning process, i.e. it resides in a 'future' (the model of teleology). Both these pictures are common in psychoanalysis. The aim of this paper is to study the figures of symbolization through the archaeology/teleology reflection model. The author tries to show that 'symbol' leans on archaeology while 'metaphor' comprises a teleological conception. In order to show the relevance of this finding, the author draws the outlines of both an archaeological and a teleological model in psychoanalysis. It is stated that the former builds on an inherent symbol model while the figure for the latter is metaphor. Copyright © 2010 Institute of Psychoanalysis.

  6. Reflective Teachers' Ethical Decision-Making Processes. (United States)

    Lampe, Judith R.; Walsh, Sharon K.

    Many indicators point to a crisis of confidence and credibility in the role of the teacher as a professional and moral leader. In response, many educational researchers are recommending that reflective teachers examine the moral and ethical issues embedded in their everyday thinking and behavior. A study was conducted, therefore, to identify and…

  7. Empathy, Self-Reflection, and Curriculum Choice (United States)

    Grosseman, Suely; Hojat, Mohammadreza; Duke, Pamela M.; Mennin, Stewart; Rosenzweig, Steven; Novack, Dennis


    We administered the Jefferson Scale of Empathy and the Groningen Reflection Ability Scale to 61 of 64 entering medical students who self-selected a problem-based learning curricular track and to 163 of 198 who self-selected a lecture-based track (response rates of 95.3% and 82.3%, respectively, with no statistically significant differences in mean…

  8. Reflections on Education and Social Mobility (United States)

    Halsey, A. H.


    This article is a brief personal reflection on the state of research into the relation between education and social mobility. Quantitative methods are both essential and advancing in this field. Sociologists seek scientific solutions but achieve ethical neutrality only with difficulty because all are tempted to bias from social and political…

  9. Reflectivity improvements for neutron mirrors and supermirrors (United States)

    Vidal, Bernard; Jiang, Z.; Samuel, Francois J.


    In order to study multilayers for neutrons optics, Ni/Ti multilayers were first realized by magnetron sputtering technique on super-polished Si wafer and Borkron glasses. Including carbon in the nickel target in order to improve neutron reflectivity, nickel carbide/titanium multilayers were deposited under the same conditions. The neutron optical quality of NiC/Ti multilayers are better than Ni/Ti stacks. The grazing angle neutron reflectivity results were subsequently confirmed by other techniques. X-ray diffraction measurements show a nickel layer crystalline (111) whereas the NiC layers are quasi-amorphous. In consequence, the a- NiC/Ti interfaces are sharper than the Ni/Ti ones. Reactive hydrogenation of titanium layers during the deposition process allows us to decrease the neutron refractive index. In this case, the contrast between the high and low refractive index increase and the Ni/Ti-H multilayers have a better reflectivity than those obtained with pure Ni/Ti materials. Moreover, strong affinity of the titanium for hydrogen reduce the Getter effect corresponding to a stabilization of the titanium layers. Accordingly, better contrast and better interfaces are obtained for NiC/TiH multilayers. Some results of super-mirrors with less than 50 layers using these types of materials are given. In these cases, we obtained more than two times the critical angle of pure nickel with a value close to one for the reflectance coefficient.

  10. Reignition of detonations by reflected shocks (United States)

    Jones, D. A.; Sichel, M.; Oran, E. S.


    Numerical simulations are used to study the diffraction, decay, and reignition that occurs when a detonation propagates past an increase in cross-sectional area in a rectangular tube. The computations solve the time-dependent two-dimensional equations describing a reactive flow in an argon-diluted stoichiometric hydrogen-oxygen mixture at atmospheric pressure. Previous studies have shown that soon after transmission to a larger area, the reaction front decouples from the leading shock and forms a decaying blast wave (“bubble”) in the larger tube. Then, depending on the initial conditions, the detonation either continues to decay or is reignited as the bubble reflects off confining surfaces. For a strongly overdriven initiating detonation, reignition occurs through an interaction between the bubble and the original contact surface. For a more weakly driven system, reignition can occur in two ways: either in the slip line and Mach stem of the Mach reflection formed when the bubble reflects off the bottom surface of the tube, or by multiple shock interactions that occur when the reflected bubble overtakes the initial detonation front. The computations show the evolution and development of the cellular structure of the steady detonation front.

  11. Reflections on the Sociology of Education (United States)

    Konstantinovskii, D. L.


    In this article, the author offers reflections on the sociology of education, beginning with a discussion on the trajectory of the rise of the sociology of education in Russia. The author examines how the sociology of education in Russia looks compared to the rest of the world. The sociological study of education in Russia and the Soviet Union has…

  12. Reflective pedagogical competences in health education

    DEFF Research Database (Denmark)

    Wistoft, Karen; Nordentoft, Helle Merete


    Health educators face value complexity in their practices as well as their reflections on practice. Actions and decisions are no longer based on traditional norms, values and objective knowledge. The complexity of social and cultural changes in health care environments often leave professionals...

  13. Fostering reflective practice with mobile technologies

    NARCIS (Netherlands)

    Tabuenca, Bernardo; Verpoorten, Dominique; Ternier, Stefaan; Westera, Wim; Specht, Marcus


    Tabuenca, B., Verpoorten, D., Ternier, S., Westera, W., & Specht, M. (2012). Fostering reflective practice with mobile technologies. In A. Moore, V. Pammer, L. Pannese, M. Prilla, K. Rajagopal, W. Reinhardt, Th. D. Ullman, & Ch. Voigt (Eds.), Proceedings of the 2nd Workshop on Awareness and

  14. Reflections … they called it 'restructuring'[1

    African Journals Online (AJOL)

    HMPG, and indeed publishing globally) was financial,[4] reflecting tough economic times and declining revenues from advertising. JA found herself accepting so-called 'native' advertising (the practice ... online, a change that has been welcomed by CPD participants) and with CME. Merged with SAMJ, the print CME carries ...


    Directory of Open Access Journals (Sweden)

    Enildo Xavier Carneiro Pessoa


    Full Text Available It deals with this article of a reflection on the 1964 Coup, based on considerations about the main powers of the twentieth century, which were placed in a bipolar way between capitalism and socialism. In the sequence, two political blocs, more or less aligned to this bipolarity, disputed the political hegemony in Brazil.

  16. Methodological Reflections on Working with Young Children

    DEFF Research Database (Denmark)

    Korn, Matthias


    This paper provides methodological reflections on an evolutionary and participatory software development process for designing interactive systems with children of very young age. The approach was put into practice for the design of a software environment for self-directed project management...

  17. Reflections on Foreign Language Education in Iran (United States)

    Farhady, Hossein; Hezaveh, Fattaneh Sajadi; Hedayati, Hora


    This article reflects upon foreign-language education in Iran. Contrary to its political and historical reputation in the world, Iran has not been well presented regarding its educational system in general and its foreign-language education in particular. Of course, a critical assessment of the strengths and weaknesses of the Iranian education…

  18. Mid infrared upconversion spectroscopy using diffuse reflectance

    DEFF Research Database (Denmark)

    Sanders, Nicolai Højer; Kehlet, Louis M.; Dam, Jeppe Seidelin


    We present a novel approach for mid infrared (mid-IR) spectral analysis using upconversion technology applied in a diffuse reflectance setup. We demonstrate experimentally that mid-IR spectral features in the 2.6-4 μm range using different test samples (e.g. zeolites) can be obtained. The results...

  19. The in situ measurement of road reflection.

    NARCIS (Netherlands)

    Schreuder, D.A.


    This paper describes a procedure that has been designed to measure P(0;0), P(2;0) and P(1;90), the three values that are the basis for the C1-C2 system for measuring road reflection of light. The system was proposed in The Netherlands, and subsequently adopted by the CIE as an alternative to the

  20. Dry etching technologies for reflective multilayer (United States)

    Iino, Yoshinori; Karyu, Makoto; Ita, Hirotsugu; Kase, Yoshihisa; Yoshimori, Tomoaki; Muto, Makoto; Nonaka, Mikio; Iwami, Munenori


    We have developed a highly integrated methodology for patterning Extreme Ultraviolet (EUV) mask, which has been highlighted for the lithography technique at the 14nm half-pitch generation and beyond. The EUV mask is characterized as a reflective-type mask which is completely different compared with conventional transparent-type of photo mask. And it requires not only patterning of absorber layer without damaging the underlying multi reflective layers (40 Si/Mo layers) but also etching multi reflective layers. In this case, the dry etch process has generally faced technical challenges such as the difficulties in CD control, etch damage to quartz substrate and low selectivity to the mask resist. Shibaura Mechatronics ARESTM mask etch system and its optimized etch process has already achieved the maximal etch performance at patterning two-layered absorber. And in this study, our process technologies of multi reflective layers will be evaluated by means of optimal combination of process gases and our optimized plasma produced by certain source power and bias power. When our ARES™ is used for multilayer etching, the user can choose to etch the absorber layer at the same time or etch only the multilayer.

  1. Engineering Design Projects as a Reflection Promoter (United States)

    Sabag, Nissim; Trotskovsky, Elena; Waks, Shlomo


    This article describes examples of reflection documented in a longitudinal research comprising two studies: a three-year three-stage study on technology project-based learning (TPBL) and a three-year two-stage study on engineering thinking (ET). Both studies used qualitative tools such as interviews, active observations, and document analysis.…

  2. Recovering masculine spirituality: A Jungian reflection. (United States)

    Gibson, T L


    A Jungian-oriented reflection is presented on the theoretical description of and possible clinical response to male midlife transitions within pastoral psychotherapy. After a brief introduction, a focused case vignette is offered, followed by a detailed theoretical discussion and outline of significant psycho-spiritual frames in the treatment of such clients and this crucial initiatory threshold in the male's life experience.

  3. The Portfolio as Metaphor for Teacher Reflection. (United States)

    Wenzlaff, Terri L.; Cummings, Katherine E.


    One university incorporated preparation of teaching portfolios into preservice teacher education, providing a link between the portfolio assignment and the development of students' abilities to reflect on their teaching. The paper notes students' reactions to the assignment, explaining how teaching portfolios can become the first stage in…

  4. Interacting Reflections on a Young Pupil's Work. (United States)

    Duffin, Janet; Simpson, Adrian


    Presents the reactions of a mathematics educator and a mathematician to a seven-year-old student's response for finding square numbers. Reflects on the mathematician's focus on the mathematics of the problem and the mathematics educator's focus on the student's systematic way of working, and discusses the common focus of student creativity. (MDH)

  5. Reflections on 25+ years of knowledge acquisition.

    NARCIS (Netherlands)

    Wielinga, B.J.


    In this paper I give a short reflection on Knowledge Acquisition as a subfield of AI and Knowledge Engineering over the last 25 years or so. My major message is that knowledge modeling is an underrated but still important method to reduce the complexity problems that arise in constructing

  6. Reflections on Psychotherapy and Aerobic Exercise. (United States)

    Silverman, Wade

    This document provides a series of reflections by a practicing psychologist on the uses of aerobic workouts in psychotherapy. Two case histories are cited to illustrate the contention that the mode of exercise, rather than simply its presence or absence, is the significant indicator of a patient's emotional well-being or psychopathology. The first…

  7. Deepening Discipline: Digital Reflection and Choreography (United States)

    Bannon, Fiona; Kirk, Carole


    In this paper, we discuss findings from a recent academic development project in which we engaged with students in an exploration of "how" they think and "what" they think about in the process of creating solo-authored choreography. The project emerged from a revisiting of the reflective frameworks identified in the validation…

  8. Social interaction and reflection for behaviour change

    NARCIS (Netherlands)

    Ploderer, Bernd; Oinas-Kukkonen, Harri; van Gemert-Pijnen, Julia E.W.C.


    This article introduces the theme issue on social interaction and reflection for behaviour change. A large body of research exists on systems designed to help users in changing their behaviours, for instance, to exercise more regularly or to reduce energy consumption. Increasingly, these systems

  9. Reflecting on BCMP Students' Experiences of Professionalism ...

    African Journals Online (AJOL)

    Method: Hatem's definition of professionalism was the stimulus that guided 25 final year BCMP students' reflections on their experiences of professionalism ... a process that was influenced by individuals and a competency that was determined by the extent to which the team pulled together for the benefit of the patients and ...

  10. Reflecting on Malaysian Teacher Trainees' Journals (United States)

    Yaacob, Aizan; Walters, Lynne Masel; Ali, Ruzlan Md; Abdullah, Sarimah Shaik; Walters, Timothy


    Purpose: In this study, 37 English Language Teaching (ELT) teacher trainees from a Malaysian university conducted an action-research project to determine whether journals kept during their fieldwork in primary schools located in an area close to the university allowed them to reflect on their beliefs and behaviors in the classroom. Methodology:…

  11. Gender Equality in Academia: A Critical Reflection (United States)

    Winchester, Hilary P. M.; Browning, Lynette


    Gender equality in academia has been monitored in Australia for the past three decades so it is timely to reflect on what progress has been made, what works, and what challenges remain. When data were first published on the gender composition of staff in Australian universities in the mid-1980s women comprised 20 per cent of academic staff and…

  12. Reflections on Racism in American Schools (United States)

    Alhumam, Ibrahim


    Reflecting on America's growing diversity in its educational system, and that the disconnect between races and culture is not even noticed, questioned, or challenged, the author observes and comments as a foreign university student studying educational leadership in the U.S. Commenting on ideas presented in Gary Howard's book, "We Can't Teach…

  13. Interdependence, Disequilibrium and Growth: Reflections on the ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Interdependence, Disequilibrium and Growth: Reflections on the Political Economy of North-South Relations at the Turn of the Century ... Le CRDI, l'Israel Science Foundation, la Fondation Azrieli et les Instituts de recherche en santé du Canada annoncent l'appel de propositions pour la quatrième ronde du Programme ...

  14. Passive seismic interferometry for reflection imaging & monitoring

    NARCIS (Netherlands)

    Almagro Vidal, C.


    Passive seismics is the set of applications that endeavours the exploration of the
    Earth’s mechanical properties using naturally occurring sources in the subsurface.
    Conventional imaging of the subsurface is achieved with the aid of reflection
    surveys of body waves from the surface.

  15. Reflections on the Laws of Life (United States)

    Elias, Maurice J.; Klein, Dena A.; DeLuca, Amy; Smith, David R.; Fattal, Laura F.; Bento, Angela; Leverett, Larry


    The Laws of Life is an international essay contest and social and emotional learning (SEL) initiative that many school districts use to build students' SEL and related abilities. In the contest, students reflect on their identities--who they are, who they want to become, and what they want their lives to stand for--by writing about the main values…

  16. Reflection in Education: A Kantian Epistemology (United States)

    Procee, Henk


    As even its defenders admit, reflection in education suffers from a lack of conceptual clarity. In this essay, Henk Procee provides a philosophical analysis of the central concepts in this domain. In the current literature, these concepts are usually taken from the pragmatic school of John Dewey and from critical social theory associated with…

  17. Reflections on Pedagogy: A Journey of Collaboration (United States)

    Woods, Christine


    One of the goals of autoethnography is to "offer lessons for further conversation". In this article, the author reflects on several lessons that were learnt along a journey in management education in the area of indigenous entrepreneurship. In particular, the author outlines her pedagogical practice as an academic engaged in teaching…

  18. Daytime Water Detection Based on Sky Reflections (United States)

    Rankin, Arturo L.; Matthies, Larry H.; Bellutta, Paolo


    Robust water detection is a critical perception requirement for unmanned ground vehicle (UGV) autonomous navigation. This is particularly true in wide-open areas where water can collect in naturally occurring terrain depressions during periods of heavy precipitation and form large water bodies. One of the properties of water useful for detecting it is that its surface acts as a horizontal mirror at large incidence angles. Water bodies can be indirectly detected by detecting reflections of the sky below the horizon in color imagery. The Jet Propulsion Laboratory (JPL) has implemented a water detector based on sky reflections that geometrically locates the pixel in the sky that is reflecting on a candidate water pixel on the ground and predicts if the ground pixel is water based on color similarity and local terrain features. This software detects water bodies in wide-open areas on cross-country terrain at mid- to far-range using imagery acquired from a forward-looking stereo pair of color cameras mounted on a terrestrial UGV. In three test sequences approaching a pond under a clear, overcast, and cloudy sky, the true positive detection rate was 100% when the UGV was beyond 7 meters of the water's leading edge and the largest false positive detection rate was 0.58%. The sky reflection based water detector has been integrated on an experimental unmanned vehicle and field tested at Ft. Indiantown Gap, PA, USA.

  19. Helping Students Reflect: Lessons from Cognitive Psychology (United States)

    Poole, Gary; Jones, Lydia; Whitfield, Michael


    The challenges of teaching students to reflect on experience and, thus, learn from it, are better understood with the application of constructs from cognitive psychology. The present paper focuses on two such constructs--self-schemas and scripts--to help educators better understand both the threats and opportunities associated with effective…

  20. Prepare, Act, Reflect: Intentional Decision Making. (United States)

    Wainwright, Judy


    Notes that teachers make intentional decisions during interaction with children and reflect on what occurs in the environment. Focuses on teacher behavior along several continua: soft-hard, simple-complex, open-closed, intrusion-seclusion, and high versus low mobility. Illustrates theory with a transcribed observation. Adapts Jones and Prescott's…

  1. MERTIS: reflective baffle design and manufacturing (United States)

    Zeh, T.; Gal, C.; Kaiser, S.; Peter, G.; Walter, I.; Helbert, J.; Jachlewski, J.; Multhaup, K.; Hiesinger, H.


    Optical instruments for remote sensing applications frequently require measures for reducing the amount of external, unwanted stray light in the optical instrument path. The reflective planet baffle design and manufacturing process for the thermal infrared imaging spectrometer MERTIS onboard of ESA's cornerstone mission BepiColombo to Mercury is presented. The baffle has to reflect the unwanted solar flux and scattered IR radiation, and minimize the heat load on the instrument. Based on optical stray light simulations and analyses of different baffle concepts the Stavroudis principle showed the best performance and the smallest number of internal reflections. The setup makes use of the optical properties of specific conic sections of revolution. These are the oblate spheroid, generated by rotating an ellipse about its minor axis, and the hyperboloid of one sheet, obtained by the rotation of a hyperbola around its conjugate axis. Due to the demanding requirements regarding surface quality, low mass and high mechanical stability, electroforming fabrication was selected for the baffle. During manufacturing, a layer of high strength nickel alloy is electrodeposited onto a diamond turned aluminum mandrel. The mandrel is subsequently chemically dissolved. Not only the baffle, but also the baffle support structure and other mating components are electroformed. Finally, the baffle and support structure are assembled and joined by an inert gas soldering process. After the optimum baffle geometry and surface roughness has been realized, the remaining total heat flux on the baffle is only dependent on the selection of the appropriate, high reflective coating.

  2. Fundus reflectance : historical and present ideas

    NARCIS (Netherlands)

    Berendschot, T.T.J.M.; Delint, P.J.; Norren, D. van


    In 1851 Helmholtz introduced the ophthalmoscope. The instrument allowed the observation of light reflected at the fundus. The development of this device was one of the major advancements in ophthalmology. Yet ophthalmoscopy allows only qualitative observation of the eye. Since 1950 attempts were

  3. Reflections on Rational-Emotive Therapy. (United States)

    Ellis, Albert


    Reflects rational-emotive therapy (RET) in 1955 and discusses some of its recent constructivist and humanist theories and practice. Distinguishes between general RET, called synonymous with general cognitive-behavioral therapy, from preferential RET, called unique kind of cognitive therapy that partially overlaps with general cognitive-behavioral…

  4. Reflection as an Indicator of Cognitive Presence (United States)

    Redmond, Petrea


    In the Community of Inquiry (CoI) model, cognitive presence indicators can be used to evaluate the quality of inquiry in a discussion forum. Engagement in critical thinking and deep knowledge can occur through reflective processes. When learners move through the four phases of cognitive presence (triggering, exploration, integration, resolution),…

  5. Reflections on "Real-World" Community Psychology (United States)

    Wolff, Tom; Swift, Carolyn


    Reflections on the history of real-world (applied) community psychologists trace their participation in the field's official guild, the Society for Community Research and Action (SCRA), beginning with the Swampscott Conference in 1965 through the current date. Four benchmarks are examined. The issues these real-world psychologists bring to the…

  6. Socialisation and professional identity: reflections of an ...

    African Journals Online (AJOL)

    ... a student and continues to shape my perspectives about college student development as a professional. My professional identity, influenced by the student affairs socialisation process and reflective practice as a professional in higher education, are discussed. Keywords: socialisation, professional identity, competencies ...

  7. Does Reflective Journal Writing Improve Course Performance? (United States)

    Cisero, Cheryl A.


    This study investigated whether a reflective journal writing assignment would improve students' course performance. A total of 166 students from undergraduate sections of a course taught by the same instructor over three semesters completed the assignment as part of their requirements. Students (N = 317) from five previous semesters of the same…

  8. Fostering Preservice Reflection through Response Journals (United States)

    Lee, Icy


    Journal writing is a kind of reflective writing that requires prospective teachers to construct knowledge through questioning their own assumptions about teaching and learning, and hence in line with the general direction of education reform in Hong Kong. This article describes a study that uses response journals as a tool for fostering reflection…

  9. Marking Moral Education: Some Reflections and Issues (United States)

    Taylor, Monica J.


    As Editor of the "Journal of Moral Education" for over 30 years, it could be said that I have witnessed a generation of international scholarship in the emerging and developing field of moral education. In this article, I offer a personal reflection on this journey, drawing on this editorial experience and as an educational researcher. I address…

  10. Virtual Classroom: Reflections of Online Learning (United States)

    Michael, Kathy


    Purpose: The purpose of this study is to identify student and staff experiences with online learning at higher education (HE) using the software Elluminate Live! Design/methodology/approach: This paper adopts a qualitative approach, focusing on the reflections of participants (student and teacher) collated over a 12 month period of piloting online…

  11. Reflective portfolios support learning, personal growth and ...

    African Journals Online (AJOL)

    Two major themes were explored – the benefit of the portfolio to the student and to faculty. For students, portfolios promoted reflective abilities and critical thinking and assisted them in planning learning needs. For faculty, the portfolios assisted in monitoring students' growth over time, identified learning gaps, helped to ...

  12. Hyperspectral Fluorescence and Reflectance Imaging Instrument (United States)

    Ryan, Robert E.; O'Neal, S. Duane; Lanoue, Mark; Russell, Jeffrey


    The system is a single hyperspectral imaging instrument that has the unique capability to acquire both fluorescence and reflectance high-spatial-resolution data that is inherently spatially and spectrally registered. Potential uses of this instrument include plant stress monitoring, counterfeit document detection, biomedical imaging, forensic imaging, and general materials identification. Until now, reflectance and fluorescence spectral imaging have been performed by separate instruments. Neither a reflectance spectral image nor a fluorescence spectral image alone yields as much information about a target surface as does a combination of the two modalities. Before this system was developed, to benefit from this combination, analysts needed to perform time-consuming post-processing efforts to co-register the reflective and fluorescence information. With this instrument, the inherent spatial and spectral registration of the reflectance and fluorescence images minimizes the need for this post-processing step. The main challenge for this technology is to detect the fluorescence signal in the presence of a much stronger reflectance signal. To meet this challenge, the instrument modulates artificial light sources from ultraviolet through the visible to the near-infrared part of the spectrum; in this way, both the reflective and fluorescence signals can be measured through differencing processes to optimize fluorescence and reflectance spectra as needed. The main functional components of the instrument are a hyperspectral imager, an illumination system, and an image-plane scanner. The hyperspectral imager is a one-dimensional (line) imaging spectrometer that includes a spectrally dispersive element and a two-dimensional focal plane detector array. The spectral range of the current imaging spectrometer is between 400 to 1,000 nm, and the wavelength resolution is approximately 3 nm. The illumination system consists of narrowband blue, ultraviolet, and other discrete

  13. Reflective writing: the student nurse's perspective on reflective writing and poetry writing. (United States)

    Coleman, Dawn; Willis, Diane S


    Reflective writing is a mandatory part of nurse education but how students develop their skills and use reflection as part of their experiential learning remains relatively unknown. Understanding reflective writing in all forms from the perspective of a student nurse is therefore important. To explore the use of reflective writing and the use of poetry in pre-registered nursing students. A qualitative design was employed to explore reflective writing in pre-registered nursing students. A small university in Scotland. BSc (Hons) Adult and Mental Health Pre-registration Student Nurses. Two focus groups were conducted with 10 student nurses during March 2012. Data was analysed thematically using the framework of McCarthy (1999). Students found the process of reflective writing daunting but valued it over time. Current educational methods, such as assessing reflective accounts, often lead to the 'narrative' being watered down and the student feeling judged. Despite this, reflection made students feel responsible for their own learning and research on the topic. Some students felt the use of models of reflection constricting, whilst poetry freed up their expression allowing them to demonstrate the compassion for their patient under their care. Poetry writing gives students the opportunity for freedom of expression, personal satisfaction and a closer connection with their patients, which the more formal approach to reflective writing did not offer. There is a need for students to have a safe and supportive forum in which to express and have their experiences acknowledged without the fear of being judged. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  14. Music decreases aortic stiffness and wave reflections. (United States)

    Vlachopoulos, Charalambos; Aggelakas, Angelos; Ioakeimidis, Nikolaos; Xaplanteris, Panagiotis; Terentes-Printzios, Dimitrios; Abdelrasoul, Mahmoud; Lazaros, George; Tousoulis, Dimitris


    Music has been related to cardiovascular health and used as adjunct therapy in patients with cardiovascular disease. Aortic stiffness and wave reflections are predictors of cardiovascular risk. We investigated the short-term effect of classical and rock music on arterial stiffness and wave reflections. Twenty healthy individuals (22.5±2.5 years) were studied on three different occasions and listened to a 30-min music track compilation (classical, rock, or no music for the sham procedure). Both classical and rock music resulted in a decrease of carotid-femoral pulse wave velocity (PWV) immediately after the end of music listening (all pclassical or rock music in a more sustained way (nadir by 6.0% and 5.8%, respectively, at time zero post-music listening, all pmusic preference was taken into consideration, both classical and rock music had a more potent effect on PWV in classical aficionados (by 0.20 m/s, p=0.003 and 0.13 m/s, p=0.015, respectively), whereas there was no effect in rock aficionados (all p=NS). Regarding wave reflections, classical music led to a more potent response in classical aficionados (AIx decrease by 9.45%), whereas rock led to a more potent response to rock aficionados (by 10.7%, all pMusic, both classical and rock, decreases aortic stiffness and wave reflections. Effect on aortic stiffness lasts for as long as music is listened to, while classical music has a sustained effect on wave reflections. These findings may have important implications, extending the spectrum of lifestyle modifications that can ameliorate arterial function. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Classification of Potential Water Bodies Using Landsat 8 OLI and a Combination of Two Boosted Random Forest Classifiers


    Ko, Byoung; Kim, Hyeong; Nam, Jae


    This study proposes a new water body classification method using top-of-atmosphere (TOA) reflectance and water indices (WIs) of the Landsat 8 Operational Land Imager (OLI) sensor and its corresponding random forest classifiers. In this study, multispectral images from the OLI sensor are represented as TOA reflectance and WI values because a classification result using two measures is better than raw spectral images. Two types of boosted random forest (BRF) classifiers are learned using TOA r...

  16. The Role of Reflection in the Effects of Community Service on Adolescent Development : A Meta-Analysis

    NARCIS (Netherlands)

    Van Goethem, Anne; Van Hoof, Anne; Orobio de Castro, Bram; Van Aken, Marcel; Hart, Daniel


    This meta-analysis assessed the effect of community service on adolescent development and the moderation of this effect by reflection, community service, and adolescent characteristics to explicate the mechanisms underlying community service effects. Random effects analyses, based on 49 studies

  17. The role of reflection in the effects of community service on adolescent development: A meta-analysis

    NARCIS (Netherlands)

    van Goethem, A.; van Hoof, A.; Orobio de Castro, B.; van Aken, M.; Hart, D.


    This meta-analysis assessed the effect of community service on adolescent development and the moderation of this effect by reflection, community service, and adolescent characteristics to explicate the mechanisms underlying community service effects. Random effects analyses, based on 49 studies

  18. Random recursive trees and the elephant random walk (United States)

    Kürsten, Rüdiger


    One class of random walks with infinite memory, so-called elephant random walks, are simple models describing anomalous diffusion. We present a surprising connection between these models and bond percolation on random recursive trees. We use a coupling between the two models to translate results from elephant random walks to the percolation process. We calculate, besides other quantities, exact expressions for the first and the second moment of the root cluster size and of the number of nodes in child clusters of the first generation. We further introduce another model, the skew elephant random walk, and calculate the first and second moment of this process.

  19. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.


    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...... of a discrete random variable....

  20. Random Numbers and Quantum Computers (United States)

    McCartney, Mark; Glass, David


    The topic of random numbers is investigated in such a way as to illustrate links between mathematics, physics and computer science. First, the generation of random numbers by a classical computer using the linear congruential generator and logistic map is considered. It is noted that these procedures yield only pseudo-random numbers since…

  1. Investigating the Randomness of Numbers (United States)

    Pendleton, Kenn L.


    The use of random numbers is pervasive in today's world. Random numbers have practical applications in such far-flung arenas as computer simulations, cryptography, gambling, the legal system, statistical sampling, and even the war on terrorism. Evaluating the randomness of extremely large samples is a complex, intricate process. However, the…

  2. Dynamic randomization and a randomization model for clinical trials data. (United States)

    Kaiser, Lee D


    Randomization models are useful in supporting the validity of linear model analyses applied to data from a clinical trial that employed randomization via permuted blocks. Here, a randomization model for clinical trials data with arbitrary randomization methodology is developed, with treatment effect estimators and standard error estimators valid from a randomization perspective. A central limit theorem for the treatment effect estimator is also derived. As with permuted-blocks randomization, a typical linear model analysis provides results similar to the randomization model results when, roughly, unit effects display no pattern over time. A key requirement for the randomization inference is that the unconditional probability that any patient receives active treatment is constant across patients; when this probability condition is violated, the treatment effect estimator is biased from a randomization perspective. Most randomization methods for balanced, 1 to 1, treatment allocation satisfy this condition. However, many dynamic randomization methods for planned unbalanced treatment allocation, like 2 to 1, do not satisfy this constant probability condition, and these methods should be avoided. Copyright © 2012 John Wiley & Sons, Ltd.

  3. Fringe-reflection photogrammetry based on poses calibration with planar mirror reflection (United States)

    Xiao, Yong-Liang; Zhong, Jianxin; Zhang, Qican; Su, Xianyu; You, Zhisheng


    Since liquid crystal display (LCD) screen locates outside of the camera's field of view in fringe-reflection photogrammetry, fringes displayed on LCD screen are obtained through specular reflection by a fixed camera. Thus, the pose calibration between camera and LCD screen is one of the main challenges in fringe-reflection photogrammetry. A markerless planar mirror is used to reflect the LCD screen more than three times, and the fringes are mapped into the fixed camera. The geometrical calibration can be accomplished by estimating the pose between the camera and virtual image of fringes. With the help of the relation between their pose, incidence and reflection ray can be unified in the camera frame, forward triangulation intersection can be operated in the camera frame to measure 3D coordinate of specular surface. In the final optimization, constraint bundle adjustment is operated to refine simultaneously the camera intrinsic parameters including distortion coefficients, estimated geometrical pose between LCD screen and camera, 3D coordinate of specular surface, with the help of absolute phase collinear constraint. Results of simulations and experiments demonstrate that the pose calibration with planar mirror reflection is simple, feasible and constraint bundle adjustment can enhance the three-dimensional coordinate measurement accuracy in fringe-reflection photogrammetry.

  4. Estimating surface reflectance from Himawari-8/AHI reflectance channels Using 6SV (United States)

    Lee, Kyeong-sang; Choi, Sungwon; Seo, Minji; Seong, Noh-hun; Han, Kyung-soo


    TOA (Top Of Atmospheric) reflectance observed by satellite is modified by the influence of atmosphere such as absorbing and scattering by molecular and gasses. Removing TOA reflectance attenuation which is caused by the atmospheric is essential. surface reflectance with compensated atmospheric effects used as important input data for land product such as Normalized Difference Vegetation Index (NDVI), Land Surface Albedo (LSA) and etc. In this study, we Second Simulation of a Satellite Signal in the Solar Spectrum Vector (6SV) Radiative Transfer Model (RTM) for atmospheric correction and estimating surface reflectance from Himawari-8/Advanced Himawari Imager (AHI) reflectance channels. 6SV has the advantage that it has high accuracy by performing the atmospheric correction by dividing the width of the satellite channel by 2.5 nm, but it is slow to use in the operation. So, we use LUT approach to reduce the computation time and avoid the intensive calculation required for retrieving surface reflectance. Estimated surface reflectance data were compared with PROBA-V S1 data to evaluate the accuracy. As a result Root Mean Square Error (RMSE) and bias were about 0.05 and -0.02. It is considered that this error is due to the difference of angle component and Spectral Response Function (SRF) of each channel.

  5. [The reciprocal reflecting team. A further modification of the reflecting team in inpatient child psychiatry]. (United States)

    Menz, W; Oswald, H P


    The purpose of reflecting teams is to instigate change in systems that have become bogged down, including helper systems. The modifications that have been made in the Andersen reflecting team since it was first described (1987) are summarized. The reflecting team technique derives from family therapy and is epistemologically based on the radical constructivism of Bateson (1981), von Förster (1985), von Glaserfeld (1985) and others. Making use of the information resources of the key workers on our child psychiatry unit, we developed another variation, a "reciprocal reflecting team". This model is suitable for use in a clinical setting because it involves all of the key individuals working with a given child. The fundamental difference between our model and Andersen's is that initially we have no reflecting phase for psychotherapists. Rather, we start with a reflecting sequence in which the multidisciplinary clinical team discusses observations, information and hypotheses about the index patient and his or her family. Our impression is that our results are compatible with those of Höger et al. (1994) that family therapy using a reflecting team effects positive change in two of three cases. Because we have no follow-up data and our sample is still very small we base this on spontaneous positive feedback from the family members regarding their satisfaction with treatment. Further evidence is provided by clinical observations on the children's behavior and on changes in family interaction.

  6. Random Projection Trees Revisited


    Dhesi, Aman; Kar, Purushottam


    The Random Projection Tree structures proposed in [Freund-Dasgupta STOC08] are space partitioning data structures that automatically adapt to various notions of intrinsic dimensionality of data. We prove new results for both the RPTreeMax and the RPTreeMean data structures. Our result for RPTreeMax gives a near-optimal bound on the number of levels required by this data structure to reduce the size of its cells by a factor $s \\geq 2$. We also prove a packing lemma for this data structure. Our...

  7. Random matrix theory

    CERN Document Server

    Deift, Percy


    This book features a unified derivation of the mathematical theory of the three classical types of invariant random matrix ensembles-orthogonal, unitary, and symplectic. The authors follow the approach of Tracy and Widom, but the exposition here contains a substantial amount of additional material, in particular, facts from functional analysis and the theory of Pfaffians. The main result in the book is a proof of universality for orthogonal and symplectic ensembles corresponding to generalized Gaussian type weights following the authors' prior work. New, quantitative error estimates are derive

  8. Random Cell Identifiers Assignment

    Directory of Open Access Journals (Sweden)

    Robert Bestak


    Full Text Available Despite integration of advanced functions that enable Femto Access Points (FAPs to be deployed in a plug-and-play manner, the femtocell concept still cause several opened issues to be resolved. One of them represents an assignment of Physical Cell Identifiers (PCIs to FAPs. This paper analyses a random based assignment algorithm in LTE systems operating in diverse femtocell scenarios. The performance of the algorithm is evaluated by comparing the number of confusions for various femtocell densities, PCI ranges and knowledge of vicinity. Simulation results show that better knowledge of vicinity can significantly reduce the number of confusions events.

  9. Random Constraint Satisfaction Problems

    Directory of Open Access Journals (Sweden)

    Amin Coja-Oghlan


    Full Text Available Random instances of constraint satisfaction problems such as k-SAT provide challenging benchmarks. If there are m constraints over n variables there is typically a large range of densities r=m/n where solutions are known to exist with probability close to one due to non-constructive arguments. However, no algorithms are known to find solutions efficiently with a non-vanishing probability at even much lower densities. This fact appears to be related to a phase transition in the set of all solutions. The goal of this extended abstract is to provide a perspective on this phenomenon, and on the computational challenge that it poses.


    Directory of Open Access Journals (Sweden)

    V. V. Zhulmina


    Full Text Available Vitiligo is a disease with unknown etiology, which is characterized by skin depigmentation areas due to melanocyte death. Lack of clear understanding of pathogenic disease processes justifies the difficulty of choosing efficient treatment methods. Repigmentation is slow and not always complete. One of the key indicators in practical dermatology is objective assessment of skin cover condition for further diagnostics, definition of therapy and dynamics of the disease.The purpose of this study is to assess skin reflection spectrum in depigmentation areas, marginal layer and visible healthy skin before and after treatment of patients with vitiligo.21 patients having vitiligo were under observation; the patients were treated in the hospital of skin and venereal diseases of the Siberian State Medical University. The authors applied noninvasive method of spectrophotometry for the first time in order to study skin reflection spectrum of patients with vitiligo. Noninvasive medical spectrophotometry is based on dependence factor of integral optical properties of biological tissues and fluids in the conditions of homeostasis and in case of pathology. In order to assess the efficiency of skin disease treatment the patients were exposed to skin spectrophotometry before the beginning of the treatment and after the treatment itself with further measurements of the reflection spectrum integral criteria. The measurements were made in depigmentation area, on the boundary with healthy skin and in remote from depigmentation area of healthy skin.Obtained results indicate the difference of skin reflection spectra in the areas under investigation. Moreover, positive dynamics of the treatment associated with the decrease in the value of reflection spectrum integral criteria in the diseased area. There were no statistically important differences of the integral criteria, calculated based on measurement results of reflection spectra on the boundary of depigmentation area

  11. Reflective practice in speech-language pathology: a scoping review. (United States)

    Caty, Marie-Ève; Kinsella, Elizabeth Anne; Doyle, Philip C


    Within the profession of speech-language pathology, there is limited information related to both conceptual and empirical perspectives of reflective practice. This review considers the key concepts and approaches to reflection and reflective practice that have been published in the speech-language pathology literature in order to identify potential research gaps. A scoping review was conducted using Arksey and O'Malley's (2005) framework. A total of 42 relevant publications were selected for review. The resulting literature mapping revealed that scholarship on reflection and reflective practice in speech-language pathology is limited. Our conceptual mapping pointed to the use of both multiple and generic terms and a lack of conceptual clarity about reflection and reflective practice in speech-language pathology. Two predominant approaches to reflection and reflective practice were identified: written reflection and reflective discussion. Both educational and clinical practice contexts were associated with reflection and reflective practice. Publications reviewed were primarily concerned with reflection and reflective practice by novices and expert practitioners. Based on this review, we posit that there is considerable need for conceptual and empirical work with a goal to support university- and work-based educational initiatives involving reflection and reflective practice in speech-language pathology.

  12. Catheter based mid-infrared reflectance and reflectance generated absorption spectroscopy (United States)

    Holman, Hoi-Ying N


    A method of characterizing conditions in a tissue, by (a) providing a catheter that has a light source that emits light in selected wavenumbers within the range of mid-IR spectrum; (b) directing the light from the catheter to an area of tissue at a location inside a blood vessel of a subject; (c) collecting light reflected from the location and generating a reflectance spectra; and (d) comparing the reflectance spectra to a reference spectra of normal tissue, whereby a location having an increased number of absorbance peaks at said selected wavenumbers indicates a tissue inside the blood vessel containing a physiological marker for atherosclerosis.

  13. Notes on the origin of inertinite macerals in coals: Observations on the importance of fungi in the origin of macrinite (United States)

    Hower, J.C.; O'Keefe, J.M.K.; Watt, M.A.; Pratt, T.J.; Eble, C.F.; Stucker, J.D.; Richardson, A.R.; Kostova, I.J.


    Macrinite is a, generally, rare inertinite maceral, often incorporating remnants and fragments of other macerals, including vitrinite, liptinite, and other inertinite. The associated inertinites include multiple forms of funginite. Funginite is also commonly found in association with vitrinite of slightly elevated reflectance and with degraded varieties of vitrinite. Together with the highly degraded macrinite, the latter two associations are here inferred to be part of a continuum of fungal and microbial degradation of peat. In any case, the origin of some macrinite is potentially distinct from that of inertinite generated by fire. ?? 2009 Elsevier B.V. All rights reserved.

  14. Shack-Hartmann reflective micro profilometer (United States)

    Gong, Hai; Soloviev, Oleg; Verhaegen, Michel; Vdovin, Gleb


    We present a quantitative phase imaging microscope based on a Shack-Hartmann sensor, that directly reconstructs the optical path difference (OPD) in reflective mode. Comparing with the holographic or interferometric methods, the SH technique needs no reference beam in the setup, which simplifies the system. With a preregistered reference, the OPD image can be reconstructed from a single shot. Also, the method has a rather relaxed requirement on the illumination coherence, thus a cheap light source such as a LED is feasible in the setup. In our previous research, we have successfully verified that a conventional transmissive microscope can be transformed into an optical path difference microscope by using a Shack-Hartmann wavefront sensor under incoherent illumination. The key condition is that the numerical aperture of illumination should be smaller than the numerical aperture of imaging lens. This approach is also applicable to characterization of reflective and slightly scattering surfaces.


    Directory of Open Access Journals (Sweden)

    Albert Bergesen


    Full Text Available Our task is to reflect upon Wagar's idea of a world party. In case such reflections are affected by the recent historical situation of the collapse of communism/existing socialism in 1989 and the implications this has for visions of progressive politics going into the 21st century. This event colors most political thinking, although for many the response has been that existing socialism was not real socialism, or that existing socialism was but the Stalinist deformation that, if avoided in the future, the 1917 project could again be resumed and human history and social relations remade anew. I don't see it that way. What existing socialism stood for in terms of the role of a vanguard party taking state power for the larger good is, now after the fall, I think off the board as a realistic program that can be sold to anyone.

  16. Efficient modulation cancellation using reflective SOAs. (United States)

    Dúill, S Ó; Marazzi, L; Parolari, P; Brenot, R; Koos, C; Freude, W; Leuthold, J


    Modulation cancellation and signal inversion are demonstrated within reflective semiconductor optical amplifiers. The effect is necessary to implement colorless optical network units for network end-users, where downstream signals need to be erased in order to reuse the carrier for upstream transmission. The results presented here indicate that reflective semiconductor optical amplifiers possess the perfect high-speed all-optical gain saturation characteristics to completely cancel the downstream modulation at microwatt optical power levels and are thus the prime candidate to be constituents of future optical network units. Theoretical considerations are supported by experiments that show the cancellation of signals with a 6 dB extinction ratio at 2.5 Gbit/s.

  17. Resolution of Reflection Seismic Data Revisited

    DEFF Research Database (Denmark)

    Hansen, Thomas Mejer; Mosegaard, Klaus; Zunino, Andrea

    lower vertical resolution of reflection seismic data. In the following we will revisit think layer model and demonstrate that there is in practice no limit to the vertical resolution using the parameterization of Widess (1973), and that the vertical resolution is limited by the noise in the data...... wavelength of the wavelet within the thin layer. Using a simple thin-layer parameterization Widess (1973) demonstrated that thin layers with thickness less that around λb/8 cannot be resolved from seismic data independent of the noise level. This has results since been widely adopted as a commonly accepted....... In general, we discuss that the resolution of reflection seismic data is controlled by the noise level and the a priori information available...

  18. Surface resonances in electron reflection from overlayers. (United States)

    Krasovskii, E E; Höcker, J; Falta, J; Flege, J I


    Electron scattering by oxygen monolayers on the Ru(0 0 0 1) surface is studied both experimentally and theoretically. Sharp transmission resonances at low energies are revealed and established to originate from critical points of a special kind in the complex band structure of the substrate. Electron reflection from the clean and oxidized Ru(0 0 0 1) is measured for kinetic energies up to 40 eV at normal incidence for oxygen coverages of 1/4, 1/2, 3/4, and one monolayer. The reflection spectra R(E) are analyzed using a Bloch-waves based ab initio scattering theory. In addition to the substrate-induced resonances the reconstructed (2 × 1) and (2 × 2) surfaces show surface resonances due to pre-emergent secondary diffraction beams. The R(E) spectra are shown to give unambiguous evidence of the hcp stacking of the oxygen layer.

  19. Researching critical reflection in management education

    DEFF Research Database (Denmark)

    Elkjaer, Bente; Nickelsen, Niels Christian Mossfeldt


    different meanings), so that it is difficult to pinpoint its many benefits and exactly how they are achieved. Given that the claims about its benefits are many and varied, it is also difficult to establish consensus on how it should be researched, and indeed what exactly is researched. This means...... it is problematic to improve how critical reflection is taught and practised in a rigorous and transferable way. This work is timely for several reasons: professionals across sectors work in increasingly complex and changing organisations that produce ambiguity and challenges to practice. Professionals need ways...... to deal with change and critical reflection provides one method for being able to incorporate changes in a way which allows individuals to preserve a sense of what is fundamentally important to them as professionals. Since many different professionals work together in most organisations, research...

  20. The making of expert clinicians: reflective practice. (United States)

    Maestre, J M; Szyld, D; Del Moral, I; Ortiz, G; Rudolph, J W


    Debriefing is a rigorous reflection process which helps trainees recognize and resolve clinical and behavioral dilemmas raised by a clinical case. This approach emphasizes eliciting trainees'assumptions about the situation and their reasons for performing as they did (mental models). It analyses their impact on actions, to understand if it is necessary to maintain them or construct new ones that may lead to better performance in the future. It blends evidence and theory from education research, the social and cognitive sciences, and experience drawn from conducting and teaching debriefing to clinicians worldwide, on how to improve professional effectiveness through "reflective practice". Copyright © 2013 Elsevier España, S.L. All rights reserved.

  1. Multiple View Stereo by Reflectance Modeling

    DEFF Research Database (Denmark)

    Kim, Sujung; Kim, Seong Dae; Dahl, Anders Lindbjerg


    Multiple view stereo is typically formulated as an optimization problem over a data term and a prior term. The data term is based on the consistency of images projected on a hypothesized surface. This consistency is based on a measure denoted a visual metric, e.g. normalized cross correlation. Here...... we argue that a visual metric based on a surface reflectance model should be founded on more observations than the degrees of freedom (dof) of the reflectance model. If (partly) specular surfaces are to be handled, this implies a model with at least two dof. In this paper, we propose to construct...... visual metrics of more than one dof using the DAISY methodology, which compares favorably to the state of the art in the experiments carried out. These experiments are based on a novel data set of eight scenes with diffuse and specular surfaces and accompanying ground truth. The performance of six...

  2. Reflectance Confocal Microscopy in Lentigo Maligna. (United States)

    Gamo, R; Pampín, A; Floristán, U


    Lentigo maligna is the most common type of facial melanoma. Diagnosis is complicated, however, as it shares clinical and dermoscopic characteristics with other cutaneous lesions of the face. Reflectance confocal microscopy is an imaging technique that permits the visualization of characteristic features of lentigo maligna. These include a disrupted honeycomb pattern and pagetoid cells with a tendency to show folliculotropism. These cells typically have a dendritic morphology, although they may also appear as round cells measuring over 20μm with atypical nuclei. Poorly defined dermal papillae and atypical cells may be seen at the dermal-epidermal junction and can form bridges resembling mitochondrial structures. Other characteristic findings include junctional swelling with atypical cells located around the follicles, resembling caput medusae. Reflectance confocal microscopy is a very useful tool for diagnosing lentigo maligna. Copyright © 2016 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Fostering Student Introspection through Guided Reflection Forms (United States)

    Wood, Laura; Matheson, Amanda; Franklin, Scott


    Student self-reflection is an important metacognitive skill to developing expert-like habits of mind. This study focuses on student responses to Guided Reflection Forms (GRFs) and individualized instructor feedback to the submissions. Student and instructor entries were hand-coded by an emergent rubric and, separately, analyzed with LIWC (Linguistic Inquiry and Word Count), a computerized text analysis program that extracts affective sentiment. Sentiment analysis supports the development of a stable basis set (rubric) to describe responses that is robust across both introductory and advanced classes. The analysis also reveals the instructor's use of the ``praise sandwich,'' instinctively embedding critiques and suggestions between specific and general encouragements. The study demonstrates the utility of validated, automated, sentiment analysis as a method by which to analyze large corpuses of written text.

  4. Reflection and refraction in active dielectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Duplaa, Maria Celeste; Perez, Liliana I; Garea, Maria Teresa [GLOmAe, Departamento de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires (Argentina) (Argentina); Matteo, Claudia L, E-mail: [Laboratorio de Sistemas LIquidos, Departamento de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires (Argentina) (Argentina)


    In this work we study and analyze in detail the characteristics of the modulus and phase of the reflection and transmission coefficients in interfaces between isotropic media, when the incident electromagnetic wave is propagating from a transparent medium towards an active one. We also demonstrate analytically that Amplified Reflection is impossible if semi-infinite media are involved. Due to these coefficients, the oscillatory or monotonic character of the phase difference between p and s modes is shown as a function of the angle of incidence for different active media. A qualitative and quantitative comparison between our own results and those obtained by many authors on absorbing media is made. We consider that this work can clarify some aspects that can contribute in the use of ellipsometric techniques for the determination of optical properties of active media.

  5. Massive Particle Reflection from Moving Mirrors (United States)

    Sfarti, Adrian


    We investigate the reflection of massive particles from moving mirrors. The adoption of the formalism based on the energy-momentum allowed us to derive the most general set of formulas, valid for massive and, in the limit, also for massless particles. We show that the momentum change of the reflecting particle always lies along the normal to the mirror, independent of the mirror speed. The subject is interesting not only to physicists designing concentrators for fascicles of massive particles and electron microscopes but also to computer scientists working in raytracing operating in the photon sector. The paper, far from being only theoretical, has profound and novel practical applications in both domains of engineering design and computer science.

  6. Examples of reflection positive field theories (United States)

    Trinchero, R.

    The requirement of reflection positivity (RP) for Euclidean field theories is considered. This is done for the cases of a scalar field, a higher derivative scalar field theory and the scalar field theory defined on a non-integer dimensional space (NIDS). It is shown that regarding RP, the analytical structure of the corresponding Schwinger functions plays an important role. For the higher derivative scalar field theory, RP does not hold. However for the scalar field theory on a NIDS, RP holds in a certain range of dimensions where the corresponding Minkowskian field is defined on a Hilbert space with a positive definite scalar product that provides a unitary representation of the Poincaré group. In addition, and motivated by the last example, it is shown that, under certain conditions, one can construct non-local reflection positive Euclidean field theories starting from the corrected two point functions of interacting local field theories.

  7. Quincke random walkers (United States)

    Pradillo, Gerardo; Heintz, Aneesh; Vlahovska, Petia


    The spontaneous rotation of a sphere in an applied uniform DC electric field (Quincke effect) has been utilized to engineer self-propelled particles: if the sphere is initially resting on a surface, it rolls. The Quincke rollers have been widely used as a model system to study collective behavior in ``active'' suspensions. If the applied field is DC, an isolated Quincke roller follows a straight line trajectory. In this talk, we discuss the design of a Quincke roller that executes a random-walk-like behavior. We utilize AC field - upon reversal of the field direction a fluctuation in the axis of rotation (which is degenerate in the plane perpendicular to the field and parallel to the surface) introduces randomness in the direction of motion. The MSD of an isolated Quincke walker depends on frequency, amplitude, and waveform of the electric field. Experiment and theory are compared. We also investigate the collective behavior of Quincke walkers,the transport of inert particles in a bath of Quincke walkers, and the spontaneous motion of a drop containing Quincke active particle. supported by NSF Grant CBET 1437545.

  8. Lectures on random interfaces

    CERN Document Server

    Funaki, Tadahisa


    Interfaces are created to separate two distinct phases in a situation in which phase coexistence occurs. This book discusses randomly fluctuating interfaces in several different settings and from several points of view: discrete/continuum, microscopic/macroscopic, and static/dynamic theories. The following four topics in particular are dealt with in the book. Assuming that the interface is represented as a height function measured from a fixed-reference discretized hyperplane, the system is governed by the Hamiltonian of gradient of the height functions. This is a kind of effective interface model called ∇φ-interface model. The scaling limits are studied for Gaussian (or non-Gaussian) random fields with a pinning effect under a situation in which the rate functional of the corresponding large deviation principle has non-unique minimizers. Young diagrams determine decreasing interfaces, and their dynamics are introduced. The large-scale behavior of such dynamics is studied from the points of view of the hyd...

  9. Random-walk enzymes (United States)

    Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.


    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C →U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

  10. Qualitative inquiry, reflective practice and jazz improvisation


    Bjerstedt, Sven


    This paper, based on my PhD empirical study, suggests that qualitative investigations, seen as reflective practices, have much in common with – and probably much to learn from – jazz improvisational practices. The complex processes of hermeneutic understanding include laying bare the researcher’s pre-understanding as well as, in the interpretation of statements, the dynamics between their holistic coherence and the agent’s intentions. Through interview excerpts, the important phenomenon of br...

  11. Unmasking online reflective practices in higher education


    Ross, Jennifer


    Online reflective practices that are high-stakes – summatively assessed, or used as evidence for progression or membership in a professional body – are increasingly prevalent in higher education, especially in professional and vocational programmes. A combination of factors is influencing their emergence: an e-learning agenda that promises efficiency and ubiquity; a proliferation of employability, transferable skills and personal development planning policies; a culture of surv...

  12. Reflection and the distance language learner


    Murphy, Linda Mary


    This research examines the role of critical reflection in learning theories and the relationship between Kolb's learning cycle and notions of the 'good' language learner, the deep approach to learning and autonomous learning in the context of adult, part-time, distance language learning. This group of learners is under-represented in the research literature. The research takes an exploratory-interpretative approach. Open University Language students had been invited by their tutors to use mat...

  13. Majorana Fermion Induced Resonant Andreev Reflection


    Law, K. T.; Lee, Patrick A.; Ng, T. K.


    We describe experimental signatures of Majorana fermion edge states, which form at the interface between a superconductor and the surface of a topological insulator. If a lead couples to the Majorana fermions through electron tunneling, the Majorana fermions induce \\textit{resonant} Andreev reflections from the lead to the grounded superconductor. The linear tunneling conductance is $0 $ ($2 e^2/h$) if there is an even (odd) number of vortices in the superconductor. Similar resonance occurs f...

  14. Reflections on reducing insulin to lose weigh. (United States)

    Wilson, Val

    Diabulimia is not a recognised medical condition, although it is thought to affect one-third of women with type 1 diabetes. Diabulimia involves deliberately omitting or reducing insulin dosages to lose weight. This article reports the reflections of women with long-duration type 1 diabetes who said that they had manipulated their insulin in the past to lose weight. Many were now dealing with serious heart and neuropathic complications, which they felt were a result of their diabulimia.

  15. On the Y555 complex reflection group


    Allcock, Daniel


    We give a computer-free proof of a theorem of Basak, describing the group generated by 16 complex reflections of order 3, satisfying the braid and commutation relations of the Y555 diagram. The group is the full isometry group of a certain lattice of signature (13,1) over the Eisenstein integers Z[cube root of 1]. Along the way we enumerate the cusps of this lattice and classify the root and Niemeier lattices over this ring.

  16. Ankylosing Spondylitis: a Reflection and a Question

    Directory of Open Access Journals (Sweden)

    Annia Deysi Hernández Martín


    Full Text Available Ankylosing spondylitis is a chronic inflammatory disease that affects the synovial membrane, joint entheses and para-articular structures of the spine, including the sacroiliac joints and limbs. We present a case of ankylosing spondylitis that had evolved for 12 years despite the relatively early diagnosis and treatment, showing flexion deformity and limitation of spinal movements. On radiological examination an early evolution to ankylosis was observed, which motivated us to make a reflection and a question.

  17. Agricultural applications of NIR reflectance and transmittance

    DEFF Research Database (Denmark)

    Gislum, René


    There has been a considerable increase in the use of near infrared (NIR) reflectance and transmittance spectroscopy technologies for rapid determination of quality parameters in agriculture, including applications within crop product quality, feed and food quality, manure quality, soil analyses etc....... As a result it was decided to arrange a seminar within the Nordic Association of Agricultural Scientists. This is a report of the meeting....

  18. Landsat Surface Reflectance Climate Data Records (United States)



    Landsat Surface Reflectance Climate Data Records (CDRs) are high level Landsat data products that support land surface change studies. Climate Data Records, as defined by the National Research Council, are a time series of measurements with sufficient length, consistency, and continuity to identify climate variability and change. The U.S. Geological Survey (USGS) is using the valuable 40-year Landsat archive to create CDRs that can be used to document changes to Earth’s terrestrial environment.

  19. Conical Reflection in Direct Simulation Monte Carlo (United States)

    Sampson, Andrew; Payne, Adam; Somers, William; Spencer, Ross


    Fenix is a particle-in-cell simulation, using a Direct Simulation Monte Carlo method, and is aimed to improve the accuracy of Inductively Coupled Plasma Mass Spectrometry (ICP-MS). It currently focuses on the ICP-MS first expansion region through a supersonic nozzle in cylindrical symmetry. Due to increased complexity in Fenix, it has become necessary to solve the general conical surface reflection problem. The previous method, the new solution, and results from the enhanced simulation will be presented.

  20. Neutron reflectivity studies of ionomer blends

    CERN Document Server

    Gabrys, B J; Bucknall, D G; Vesely, D; Braiewa, R; Weiss, R A


    Preliminary results are presented of a neutron reflectivity study of the interfacial width between lithium- and zinc-sulphonated deuterated polystyrene with polycarbonate (PC). Both systems are partially miscible and exhibit an upper critical solution temperature behaviour. The interdiffusion in these systems was measured by annealing at a temperature above the glass-transition temperature of both polymers. The interfacial profiles obtained for these systems were described by symmetric Gaussian interfaces. No significant diffusion was observed. (orig.)