Factors controlling contrail cirrus optical depth

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B. Kärcher

2009-08-01

Full Text Available Aircraft contrails develop into contrail cirrus by depositional growth and sedimentation of ice particles and horizontal spreading due to wind shear. Factors controlling this development include temperature, ice supersaturation, thickness of ice-supersaturated layers, and vertical gradients in the horizontal wind field. An analytical microphysical cloud model is presented and validated that captures these processes. Many individual contrail cirrus are simulated that develop differently owing to the variability in the controlling factors, resulting in large samples of cloud properties that are statistically analyzed. Contrail cirrus development is studied over the first four hours past formation, similar to the ages of line-shaped contrails that were tracked in satellite imagery on regional scales. On these time scales, contrail cirrus optical depth and microphysical variables exhibit a marked variability, expressed in terms of broad and skewed probability distribution functions. Simulated mean optical depths at a wavelength of 0.55 μm range from 0.05-0.5 and a substantial fraction 20-50% of contrail cirrus stay subvisible (optical depth <0.02, depending on meteorological conditions.

A detailed analysis based on an observational case study over the continental USA suggests that previous satellite measurements of line-shaped persistent contrails have missed about 89%, 50%, and 11% of contrails with optical depths 0-0.05, 0.05-0.1, and 0.1-0.2, respectively, amounting to 65% of contrail coverage of all optical depths. When comparing observations with simulations and when estimating the contrail cirrus climate impact, not only mean values but also the variability in optical depth and microphysical properties need to be considered.

77 FR 3585 - Airworthiness Directives; Cirrus Design Corporation Airplanes

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2012-01-25

... Airworthiness Directives; Cirrus Design Corporation Airplanes AGENCY: Federal Aviation Administration (FAA), DOT... Corporation (Cirrus) Model SR22T airplanes. This AD was prompted by reports of partial loss of engine power.... ADDRESSES: For service information identified in this AD, contact Cirrus Design Corporation, 4515 Taylor...

Remote sensing of contrails and aircraft altered cirrus clouds

Energy Technology Data Exchange (ETDEWEB)

Palikonda, R.; Nguyen, L.; Garber, D.P.; Smith, W.L. Jr [Analytical Services and Materials, Inc., Hampton, VA (United States); Minnis, P.; Young, D.F. [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center

1997-12-31

Analyses of satellite imagery are used to show that contrails can develop into fully extended cirrus cloud systems. Contrails can be advective on great distances, but would appear to observers as natural cirrus clouds. The conversion of simple contrails into cirrus may help explain the apparent increase of cloudiness over populated areas since the beginning of commercial jet air travel. Statistics describing the typical growth, advection, and lifetime of contrail cirrus is needed to evaluate their effects on climate. (author) 4 refs.

Remote sensing of contrails and aircraft altered cirrus clouds

Energy Technology Data Exchange (ETDEWEB)

Palikonda, R; Nguyen, L; Garber, D P; Smith, Jr, W L [Analytical Services and Materials, Inc., Hampton, VA (United States); Minnis, P; Young, D F [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center

1998-12-31

Analyses of satellite imagery are used to show that contrails can develop into fully extended cirrus cloud systems. Contrails can be advective on great distances, but would appear to observers as natural cirrus clouds. The conversion of simple contrails into cirrus may help explain the apparent increase of cloudiness over populated areas since the beginning of commercial jet air travel. Statistics describing the typical growth, advection, and lifetime of contrail cirrus is needed to evaluate their effects on climate. (author) 4 refs.

Orographic cirrus in a future climate

Directory of Open Access Journals (Sweden)

H. Joos

2009-10-01

Full Text Available A cloud resolving model (CRM is used to investigate the formation of orographic cirrus clouds in the current and future climate. The formation of cirrus clouds depends on a variety of dynamical and thermodynamical processes, which act on different scales. First, the capability of the CRM in realistically simulating orographic cirrus clouds has been tested by comparing the simulated results to aircraft measurements of an orographic cirrus cloud. The influence of a warmer climate on the microphysical and optical properties of cirrus clouds has been investigated by initializing the CRM with vertical profiles of horizontal wind, potential temperature and equivalent potential temperature, respectively. The vertical profiles are extracted from IPCC A1B simulations for the current climate and for the period 2090–2099 for two regions representative for North and South America. The influence of additional moisture in a future climate on the propagation of gravity waves and the formation of orographic cirrus could be estimated. In a future climate, the increase in moisture dampens the vertical propagation of gravity waves and the occurring vertical velocities in the moist simulations. Together with higher temperatures fewer ice crystals nucleate homogeneously. Assuming that the relative humidity does not change in a warmer climate the specific humidity in the model is increased. This increase in specific humidity in a warmer climate results in a higher ice water content. The net effect of a reduced ice crystal number concentration and a higher ice water content is an increased optical depth. However, in some moist simulations dynamical changes contribute to changes in the ice water content, ice crystal number concentration and optical depth. For the corresponding dry simulations dynamical changes are more pronounced leading to a decreased optical depth in a future climate in some cases.

Aviation effects on already-existing cirrus clouds.

Science.gov (United States)

Tesche, Matthias; Achtert, Peggy; Glantz, Paul; Noone, Kevin J

2016-06-21

Determining the effects of the formation of contrails within natural cirrus clouds has proven to be challenging. Quantifying any such effects is necessary if we are to properly account for the influence of aviation on climate. Here we quantify the effect of aircraft on the optical thickness of already-existing cirrus clouds by matching actual aircraft flight tracks to satellite lidar measurements. We show that there is a systematic, statistically significant increase in normalized cirrus cloud optical thickness inside mid-latitude flight tracks compared with adjacent areas immediately outside the tracks.

A Characterization of Cirrus Cloud Properties That Affect Laser Propagation

National Research Council Canada - National Science Library

Norquist, Donald C; Desrochers, Paul R; McNicholl, Patrick J; Roadcap, John R

2008-01-01

Future high-altitude laser systems may be affected by cirrus clouds. Laser transmission models were applied to measured and retrieved cirrus properties to determine cirrus impact on power incident on a target or receiver...

On the distribution of relative humidity in cirrus clouds

Directory of Open Access Journals (Sweden)

P. Spichtinger

2004-01-01

Full Text Available We have analysed relative humidity statistics from measurements in cirrus clouds taken unintentionally during the Measurement of OZone by Airbus In-service airCraft project (MOZAIC. The shapes of the in-cloud humidity distributions change from nearly symmetric in relatively warm cirrus (warmer than −40°C to considerably positively skew (i.e. towards high humidities in colder clouds. These results are in agreement to findings obtained recently from the INterhemispheric differences in Cirrus properties from Anthropogenic emissions (INCA campaign (Ovarlez et al., 2002. We interprete the temperature dependence of the shapes of the humidity distributions as an effect of the length of time a cirrus cloud needs from formation to a mature equilibrium stage, where the humidity is close to saturation. The duration of this transitional period increases with decreasing temperature. Hence cold cirrus clouds are more often met in the transitional stage than warm clouds.

A statistical comparison of cirrus particle size distributions measured using the 2-D stereo probe during the TC4, SPARTICUS, and MACPEX flight campaigns with historical cirrus datasets

Science.gov (United States)

Schwartz, M. Christian

2017-08-01

This paper addresses two straightforward questions. First, how similar are the statistics of cirrus particle size distribution (PSD) datasets collected using the Two-Dimensional Stereo (2D-S) probe to cirrus PSD datasets collected using older Particle Measuring Systems (PMS) 2-D Cloud (2DC) and 2-D Precipitation (2DP) probes? Second, how similar are the datasets when shatter-correcting post-processing is applied to the 2DC datasets? To answer these questions, a database of measured and parameterized cirrus PSDs - constructed from measurements taken during the Small Particles in Cirrus (SPARTICUS); Mid-latitude Airborne Cirrus Properties Experiment (MACPEX); and Tropical Composition, Cloud, and Climate Coupling (TC4) flight campaigns - is used.Bulk cloud quantities are computed from the 2D-S database in three ways: first, directly from the 2D-S data; second, by applying the 2D-S data to ice PSD parameterizations developed using sets of cirrus measurements collected using the older PMS probes; and third, by applying the 2D-S data to a similar parameterization developed using the 2D-S data themselves. This is done so that measurements of the same cloud volumes by parameterized versions of the 2DC and 2D-S can be compared with one another. It is thereby seen - given the same cloud field and given the same assumptions concerning ice crystal cross-sectional area, density, and radar cross section - that the parameterized 2D-S and the parameterized 2DC predict similar distributions of inferred shortwave extinction coefficient, ice water content, and 94 GHz radar reflectivity. However, the parameterization of the 2DC based on uncorrected data predicts a statistically significantly higher number of total ice crystals and a larger ratio of small ice crystals to large ice crystals than does the parameterized 2D-S. The 2DC parameterization based on shatter-corrected data also predicts statistically different numbers of ice crystals than does the parameterized 2D-S, but the

A statistical comparison of cirrus particle size distributions measured using the 2-D stereo probe during the TC4, SPARTICUS, and MACPEX flight campaigns with historical cirrus datasets

Directory of Open Access Journals (Sweden)

M. C. Schwartz

2017-08-01

Full Text Available This paper addresses two straightforward questions. First, how similar are the statistics of cirrus particle size distribution (PSD datasets collected using the Two-Dimensional Stereo (2D-S probe to cirrus PSD datasets collected using older Particle Measuring Systems (PMS 2-D Cloud (2DC and 2-D Precipitation (2DP probes? Second, how similar are the datasets when shatter-correcting post-processing is applied to the 2DC datasets? To answer these questions, a database of measured and parameterized cirrus PSDs – constructed from measurements taken during the Small Particles in Cirrus (SPARTICUS; Mid-latitude Airborne Cirrus Properties Experiment (MACPEX; and Tropical Composition, Cloud, and Climate Coupling (TC4 flight campaigns – is used.Bulk cloud quantities are computed from the 2D-S database in three ways: first, directly from the 2D-S data; second, by applying the 2D-S data to ice PSD parameterizations developed using sets of cirrus measurements collected using the older PMS probes; and third, by applying the 2D-S data to a similar parameterization developed using the 2D-S data themselves. This is done so that measurements of the same cloud volumes by parameterized versions of the 2DC and 2D-S can be compared with one another. It is thereby seen – given the same cloud field and given the same assumptions concerning ice crystal cross-sectional area, density, and radar cross section – that the parameterized 2D-S and the parameterized 2DC predict similar distributions of inferred shortwave extinction coefficient, ice water content, and 94 GHz radar reflectivity. However, the parameterization of the 2DC based on uncorrected data predicts a statistically significantly higher number of total ice crystals and a larger ratio of small ice crystals to large ice crystals than does the parameterized 2D-S. The 2DC parameterization based on shatter-corrected data also predicts statistically different numbers of ice crystals than does the

MST radar and polarization lidar observations of tropical cirrus

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Y. Bhavani Kumar

2001-08-01

Full Text Available Significant gaps in our understanding of global cirrus effects on the climate system involve the role of frequently occurring tropical cirrus. Much of the cirrus in the atmosphere is largely due to frequent cumulus and convective activity in the tropics. In the Indian sub-tropical region, the deep convective activity is very prominent from April to December, which is a favorable period for the formation of deep cumulus clouds. The fibrous anvils of these clouds, laden with ice crystals, are one of the source mechanisms for much of the cirrus in the atmosphere. In the present study, several passages of tropical cirrus were investigated by simultaneously operating MST radar and a co-located polarization lidar at the National MST Radar Facility (NMRF, Gadanki (13.45° N, 79.18° E, India to understand its structure, the background wind field and the microphysics at the cloud boundaries. The lidar system used is capable of measuring the degree of depolarization in the laser backscatter. It has identified several different cirrus structures with a peak linear depolarization ratio (LDR in the range of 0.1 to 0.32. Simultaneous observations of tropical cirrus by the VHF Doppler radar indicated a clear enhancement of reflectivity detected in the vicinity of the cloud boundaries, as revealed by the lidar and are strongly dependent on observed cloud LDR. An inter-comparison of radar reflectivity observed for vertical and oblique beams reveals that the radar-enhanced reflectivity at the cloud boundaries is also accompanied by significant aspect sensitivity. These observations indicate the presence of anisotropic turbulence at the cloud boundaries. Radar velocity measurements show that boundaries of cirrus are associated with enhanced horizontal winds, significant vertical shear in the horizontal winds and reduced vertical velocity. Therefore, these measurements indicate that a circulation at the cloud boundaries suggest an entrainment taking place close to

MST radar and polarization lidar observations of tropical cirrus

Directory of Open Access Journals (Sweden)

Y. Bhavani Kumar

Full Text Available Significant gaps in our understanding of global cirrus effects on the climate system involve the role of frequently occurring tropical cirrus. Much of the cirrus in the atmosphere is largely due to frequent cumulus and convective activity in the tropics. In the Indian sub-tropical region, the deep convective activity is very prominent from April to December, which is a favorable period for the formation of deep cumulus clouds. The fibrous anvils of these clouds, laden with ice crystals, are one of the source mechanisms for much of the cirrus in the atmosphere. In the present study, several passages of tropical cirrus were investigated by simultaneously operating MST radar and a co-located polarization lidar at the National MST Radar Facility (NMRF, Gadanki (13.45° N, 79.18° E, India to understand its structure, the background wind field and the microphysics at the cloud boundaries. The lidar system used is capable of measuring the degree of depolarization in the laser backscatter. It has identified several different cirrus structures with a peak linear depolarization ratio (LDR in the range of 0.1 to 0.32. Simultaneous observations of tropical cirrus by the VHF Doppler radar indicated a clear enhancement of reflectivity detected in the vicinity of the cloud boundaries, as revealed by the lidar and are strongly dependent on observed cloud LDR. An inter-comparison of radar reflectivity observed for vertical and oblique beams reveals that the radar-enhanced reflectivity at the cloud boundaries is also accompanied by significant aspect sensitivity. These observations indicate the presence of anisotropic turbulence at the cloud boundaries. Radar velocity measurements show that boundaries of cirrus are associated with enhanced horizontal winds, significant vertical shear in the horizontal winds and reduced vertical velocity. Therefore, these measurements indicate that a circulation at the cloud boundaries suggest an entrainment taking place close to

A one year Landsat 8 conterminous United States study of spatial and temporal patterns of cirrus and non-cirrus clouds and implications for the long term Landsat archive.

Science.gov (United States)

Kovalskyy, V.; Roy, D. P.

2014-12-01

The successful February 2013 launch of the Landsat 8 satellite is continuing the 40+ year legacy of the Landsat mission. The payload includes the Operational Land Imager (OLI) that has a new 1370 mm band designed to monitor cirrus clouds and the Thermal Infrared Sensor (TIRS) that together provide 30m low, medium and high confidence cloud detections and 30m low and high confidence cirrus cloud detections. A year of Landsat 8 data over the Conterminous United States (CONUS), composed of 11,296 acquisitions, was analyzed comparing the spatial and temporal incidence of these cloud and cirrus states. This revealed (i) 36.5% of observations were detected with high confidence cloud with spatio-temporal patterns similar to those observed by previous Landsat 7 cloud analyses, (ii) 29.2% were high confidence cirrus, (iii) 20.9% were both high confidence cloud and high confidence cirrus, (iv) 8.3% were detected as high confidence cirrus but not as high confidence cloud. The results illustrate the value of the cirrus band for improved Landsat 8 terrestrial monitoring but imply that the historical CONUS Landsat archive has a similar 8% of undetected cirrus contaminated pixels. The implications for long term Landsat time series records, including the global Web Enabled Landsat Data (WELD) product record, are discussed.

Microphysical parameters of cirrus clouds using lidar at a tropical station, Gadanki, Tirupati (13.5° N, 79.2°E), India

Science.gov (United States)

Satyanarayana, M.; Radhakrishnan, S.-R.; Krishnakumar, V.; Mahadevan Pillai, V. P.; Raghunath, K.

2008-12-01

Cirrus clouds have been identified as one of the most uncertain component in the atmospheric research. It is known that cirrus clouds modulate the earth's climate through direct and indirect modification of radiation. The role of cirrus clouds depends mainly on their microphysical properties. To understand cirrus clouds better, we must observe and characterize their properties. In-situ observation of such clouds is a challenging experiment, as the clouds are located at high altitudes. Active remote sensing method based on lidar can detect high and thin cirrus clouds with good spatial and temporal resolution. We present the result obtained on the microphysical properties of the cirrus clouds at two Tropical stations namely Gadhanki, Tirupati (13.50 N, 79.20 E), India and Trivandrum (13.50 N, 770 E) Kerala, India from the ground based pulsed Nd: YAG lidar systems installed at the stations. A variant of the widely used Klett's lidar inversion method with range dependent scattering ratio is used for the present study for the retrieval of aerosol extinction and microphysical parameters of cirrus cloud.

Modeled Impact of Cirrus Cloud Increases Along Aircraft Flight Paths

Science.gov (United States)

Rind, David; Lonergan, P.; Shah, K.

1999-01-01

The potential impact of contrails and alterations in the lifetime of background cirrus due to subsonic airplane water and aerosol emissions has been investigated in a set of experiments using the GISS GCM connected to a q-flux ocean. Cirrus clouds at a height of 12-15km, with an optical thickness of 0.33, were input to the model "x" percentage of clear-sky occasions along subsonic aircraft flight paths, where x is varied from .05% to 6%. Two types of experiments were performed: one with the percentage cirrus cloud increase independent of flight density, as long as a certain minimum density was exceeded; the other with the percentage related to the density of fuel expenditure. The overall climate impact was similar with the two approaches, due to the feedbacks of the climate system. Fifty years were run for eight such experiments, with the following conclusions based on the stable results from years 30-50 for each. The experiments show that adding cirrus to the upper troposphere results in a stabilization of the atmosphere, which leads to some decrease in cloud cover at levels below the insertion altitude. Considering then the total effect on upper level cloud cover (above 5 km altitude), the equilibrium global mean temperature response shows that altering high level clouds by 1% changes the global mean temperature by 0.43C. The response is highly linear (linear correlation coefficient of 0.996) for high cloud cover changes between 0. 1% and 5%. The effect is amplified in the Northern Hemisphere, more so with greater cloud cover change. The temperature effect maximizes around 10 km (at greater than 40C warming with a 4.8% increase in upper level clouds), again more so with greater warming. The high cloud cover change shows the flight path influence most clearly with the smallest warming magnitudes; with greater warming, the model feedbacks introduce a strong tropical response. Similarly, the surface temperature response is dominated by the feedbacks, and shows

Classifying stages of cirrus life-cycle evolution

Science.gov (United States)

Urbanek, Benedikt; Groß, Silke; Schäfler, Andreas; Wirth, Martin

2018-04-01

Airborne lidar backscatter data is used to determine in- and out-of-cloud regions. Lidar measurements of water vapor together with model temperature fields are used to calculate relative humidity over ice (RHi). Based on temperature and RHi we identify different stages of cirrus evolution: homogeneous and heterogeneous freezing, depositional growth, ice sublimation and sedimentation. We will present our classification scheme and first applications on mid-latitude cirrus clouds.

Climatology analysis of cirrus cloud in ARM site: South Great Plain

Science.gov (United States)

Olayinka, K.

2017-12-01

Cirrus cloud play an important role in the atmospheric energy balance and hence in the earth's climate system. The properties of optically thin clouds can be determined from measurements of transmission of the direct solar beam. The accuracy of cloud optical properties determined in this way is compromised by contamination of the direct transmission by light that is scattered into the sensors field of view. With the forward scattering correction method developed by Min et al., (2004), the accuracy of thin cloud retrievals from MFRSR has been improved. Our result shows over 30% of cirrus cloud present in the atmosphere are within optical depth between (1-2). In this study, we do statistics studies on cirrus clouds properties based on multi-years cirrus cloud measurements from MFRSR at ARM site from the South Great Plain (SGP) site due to its relatively easy accessibility, wide variability of climate cloud types and surface flux properties, large seasonal variation in temperature and specific humidity. Through the statistic studies, temporal and spatial variations of cirrus clouds are investigated. Since the presence of cirrus cloud increases the effect of greenhouse gases, we will retrieve the aerosol optical depth in all the cirrus cloud regions using a radiative transfer model for atmospheric correction. Calculate thin clouds optical depth (COD), and aerosol optical depth (AOD) using a radiative transfer model algorithm, e.g.: MODTRAN (MODerate resolution atmospheric TRANsmission)

Cirrus Susceptibility to Changes in Ice Nuclei: Physical Processes, Model Uncertainties, and Measurement Needs

Science.gov (United States)

Jensen, Eric

2018-01-01

One of the proposed concepts for mitigating the warming effect of increasing greenhouse gases is seeding cirrus cloud with ice nuclei (IN) in order to reduce the lifetime and coverage of cold cirrus that have a net warming impact on the earth's surface. Global model simulations of the net impact of changing upper tropospheric IN have given widely disparate results, partly as a result of poor understanding of ice nucleation processes in the current atmosphere, and partly as a result of poor representation of these processes in global models. Here, we present detailed process-model simulations of tropical tropopause layer (TTL) transport and cirrus formation with ice nuclei properties based on recent laboratory nucleation experiments and field measurements of aerosol composition. The model is used to assess the sensitivity of TTL cirrus occurrence frequency and microphysical properties to the abundance and efficacy of ice nuclei. The simulated cloud properties compared with recent high-altitude aircraft measurements of TTL cirrus and ice supersaturation. We find that abundant effective IN (either from glassy organic aerosols or crystalline ammonium sulfate with concentrations greater than about 100/L) prevent the occurrences of large ice concentration and large ice supersaturations, both of which are clearly indicated by the in situ observations. We find that concentrations of effective ice nuclei larger than about 50/L can drive significant changes in cirrus microphysical properties and occurrence frequency. However, the cloud occurrence frequency can either increase or decrease, depending on the efficacy and abundance of IN added to the TTL. We suggest that our lack of information about ice nuclei properties in the current atmosphere, as well as uncertainties in ice nucleation processes and their representations in global models, preclude meaningful estimates of climate impacts associated with addition of ice nuclei in the upper troposphere. We will briefly discuss

Characteristics of cirrus clouds and tropical tropopause layer: Seasonal variation and long-term trends

Science.gov (United States)

Pandit, Amit Kumar; Gadhavi, Harish; Ratnam, M. Venkat; Jayaraman, A.; Raghunath, K.; Rao, S. Vijaya Bhaskara

2014-12-01

In the present study, characteristics of tropical cirrus clouds observed during 1998-2013 using a ground-based lidar located at Gadanki (13.5°N, 79.2°E), India, are presented. Altitude occurrences of cirrus clouds as well as its top and base heights are estimated using the advanced mathematical tool, wavelet covariance transform (WCT). The association of observed cirrus cloud properties with the characteristics of tropical tropopause layer (TTL) is investigated using co-located radiosonde measurements available since 2006. In general, cirrus clouds occurred for about 44% of the total lidar observation time (6246 h). The most probable altitude at which cirrus clouds occurr is 14.5 km. The occurrence of cirrus clouds exhibited a strong seasonal dependence with maximum occurrence during monsoon season (76%) and minimum occurrence during winter season (33%) which is consistent with the results reported recently using space-based lidar measurements. Most of the time, cirrus top was located within the TTL (between cold point and convective outflow level) while cirrus base occurred near the convective outflow level. The geometrical thickness of the cirrus cloud is found to be higher during monsoon season compared to winter and there exists a weak inverse relation with TTL thickness. During the observation period the percentage occurrence of cirrus clouds near the tropopause showed an 8.4% increase at 70% confidence level. In the last 16 years, top and base heights of cirrus cloud increased by 0.56 km and 0.41 km, respectively.

Measurements of Terminal Velocities of Cirrus Clouds in the Upper Trosphere

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Nee Jan Bai

2016-01-01

Full Text Available Cirrus clouds are composed of ice crystals condensed from humidity due to low temperature condition in the upper atmosphere. The microphysics of cirrus clouds including sizes and shapes of ice particles are not well understood but are important in climate modeling. Ice crystal will fall under gravitational sedimentation to reach terminal velocities which depend on the size, mass, and ice habit. We studied here the terminal velocity of cirrus clouds by using lidar observations at Chungli (25N, 121E. The terminal velocities for a few cases of stable cirrus clouds are measured to determine the ice particle sizes and processes in the upper atmosphere.

76 FR 67631 - Airworthiness Directives; Cirrus Design Corporation Airplanes

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2011-11-02

... Corporation, 4515 Taylor Circle, Duluth, Minnesota 55811- 1548, phone: (218) 788-3000; fax: (218) 788-3525... as applicable. (f) Compliance Comply with this AD following Cirrus Design Corporation SR22T Service... this AD, contact Cirrus Design Corporation, 4515 Taylor Circle, Duluth, Minnesota 55811-1548, phone...

Aerosol-cirrus interactions: a number based phenomenon at all?

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M. Seifert

2004-01-01

Full Text Available In situ measurements of the partitioning of aerosol particles within cirrus clouds were used to investigate aerosol-cloud interactions in ice clouds. The number density of interstitial aerosol particles (non-activated particles in between the cirrus crystals was compared to the number density of cirrus crystal residuals. The data was obtained during the two INCA (Interhemispheric Differences in Cirrus Properties from Anthropogenic Emissions campaigns, performed in the Southern Hemisphere (SH and Northern Hemisphere (NH midlatitudes. Different aerosol-cirrus interactions can be linked to the different stages of the cirrus lifecycle. Cloud formation is linked to positive correlations between the number density of interstitial aerosol (Nint and crystal residuals (Ncvi, whereas the correlations are smaller or even negative in a dissolving cloud. Unlike warm clouds, where the number density of cloud droplets is positively related to the aerosol number density, we observed a rather complex relationship when expressing Ncvi as a function of Nint for forming clouds. The data sets are similar in that they both show local maxima in the Nint range 100 to 200cm, where the SH- maximum is shifted towards the higher value. For lower number densities Nint and Ncvi are positively related. The slopes emerging from the data suggest that a tenfold increase in the aerosol number density corresponds to a 3 to 4 times increase in the crystal number density. As Nint increases beyond the ca. 100 to 200cm, the mean crystal number density decreases at about the same rate for both data sets. For much higher aerosol number densities, only present in the NH data set, the mean Ncvi remains low. The situation for dissolving clouds allows us to offer two possible, but at this point only speculative, alternative interactions between aerosols and cirrus: evaporating clouds might be associated with a source of aerosol particles, or air pollution (high aerosol number density might

Cirrus and aerosol lidar profilometer - analysis and results

Energy Technology Data Exchange (ETDEWEB)

Spinhirne, J.D.; Scott, V.S. [NASA Goddard Space Flight Center, Greenbelt, MD (United States); Reagan, J.A.; Galbraith, A. [Univ. of Arizona, Tucson, AZ (United States)

1996-04-01

A cloud and aerosol lidar set from over a year of near continuous operation of a micro pulse lidar (MPL) instrument at the Cloud and Radiation Testbed (CART) site has been established. MPL instruments are to be included in the Ames Research Center (ARC) instrument compliments for the SW Pacific and Arctic ARM sites. Operational processing algorithms are in development for the data sets. The derived products are to be cloud presence and classification, base height, cirrus thickness, cirrus optical thickness, cirrus extinction profile, aerosol optical thickness and profile, and planetary boundary layer (PBL) height. A cloud presence and base height algorithm is in use, and a data set from the CART site is available. The scientific basis for the algorithm development of the higher level data products and plans for implementation are discussed.

UV Raman lidar measurements of relative humidity for the characterization of cirrus cloud microphysical properties

Directory of Open Access Journals (Sweden)

G. Masiello

2009-11-01

Full Text Available Raman lidar measurements performed in Potenza by the Raman lidar system BASIL in the presence of cirrus clouds are discussed. Measurements were performed on 6 September 2004 in the frame of the Italian phase of the EAQUATE Experiment.

The major feature of BASIL is represented by its capability to perform high-resolution and accurate measurements of atmospheric temperature and water vapour, and consequently relative humidity, both in daytime and night-time, based on the application of the rotational and vibrational Raman lidar techniques in the UV. BASIL is also capable to provide measurements of the particle backscatter and extinction coefficient, and consequently lidar ratio (at the time of these measurements, only at one wavelength, which are fundamental to infer geometrical and microphysical properties of clouds.

A case study is discussed in order to assess the capability of Raman lidars to measure humidity in presence of cirrus clouds, both below and inside the cloud. While air inside the cloud layers is observed to be always under-saturated with respect to water, both ice super-saturation and under-saturation conditions are found inside these clouds. Upper tropospheric moistening is observed below the lower cloud layer.

The synergic use of the data derived from the ground based Raman Lidar and of spectral radiances measured by the NAST-I Airborne Spectrometer allows the determination of the temporal evolution of the atmospheric cooling/heating rates due to the presence of the cirrus cloud.

Lidar measurements beneath the cirrus cloud layer have been interpreted using a 1-D cirrus cloud model with explicit microphysics. The 1-D simulations indicate that sedimentation-moistening has contributed significantly to the moist anomaly, but other mechanisms are also contributing. This result supports the hypothesis that the observed mid-tropospheric humidification is a real feature which is

Insights on the Feasibility, Modeling and Field Testing of Cirrus Cloud Thinning from Satellite Remote Sensing

Science.gov (United States)

Mitchell, D. L.; Garnier, A.; Mejia, J.; Avery, M. A.; Erfani, E.

2016-12-01

To date, it is not clear whether the climate intervention method known as cirrus cloud thinning (CCT) can be viable since it requires cirrus clouds to form through homogeneous ice nucleation (henceforth hom) and some recent GCM studies predict cirrus are formed primarily through heterogeneous ice nucleation (henceforth het). A new CALIPSO infrared retrieval method has been developed for single-layer cirrus cloud that measures the temperature dependence of their layer-averaged number concentration N, effective diameter De and ice water content for optical depths (OD) between 0.3 and 3.0. Based on N, the prevailing ice nucleation mechanism (hom or het) can be estimated as a function of temperature, season, latitude and surface type. These satellite results indicate that seeding cirrus clouds at high latitudes during winter may produce significant global surface cooling. This is because hom often appears to dominate over land during winter north of 30°N latitude while the same appears true for most of the Southern Hemisphere (south of 30°S) during all seasons. Moreover, the sampled cirrus cloud frequency of occurrence in the Arctic is at least twice as large during winter relative to other seasons, while frequency of occurrence in the Antarctic peaks in the spring and is second-highest during winter. During Arctic winter, a combination of frequent hom cirrus, maximum cirrus coverage and an extreme or absent sun angle produces the maximum seasonal cirrus net radiative forcing (warming). Thus a reduction in OD and coverage (via CCT) for these cirrus clouds could yield a significant net cooling effect. From these CALIPSO retrievals, De-T relationships are generated as a function of season, latitude and surface type (land vs. ocean). These will be used in CAM5 to estimate De and the ice fall speed, from which the cirrus radiative forcing will be estimated during winter north of 30°latitude, where hom cirrus are common. Another CAM5 simulation will replace the hom

Cloud-radiation interactions - Effects of cirrus optical thickness feedbacks

Science.gov (United States)

Somerville, Richard C. J.; Iacobellis, Sam

1987-01-01

The paper is concerned with a cloud-radiation feedback mechanism which may be an important component of the climate changes expected from increased atmospheric concentrations of carbon dioxide and other trace greenhouse gases. A major result of the study is that cirrus cloud optical thickness feedbacks may indeed tend to increase the surface warming due to trace gas increases. However, the positive feedback from cirrus appears to be generally weaker than the negative effects due to lower clouds. The results just confirm those of earlier research indicating that the net effect of cloud optical thickness feedbacks may be a negative feedback which may substantially (by a factor of about 2) reduce the surface warming due to the doubling of CO2, even in the presence of cirrus clouds.

Revisiting the iris effect of tropical cirrus clouds with TRMM and A-Train satellite data

Science.gov (United States)

Choi, Yong-Sang; Kim, WonMoo; Yeh, Sang-Wook; Masunaga, Hirohiko; Kwon, Min-Jae; Jo, Hyun-Su; Huang, Lei

2017-06-01

Just as the iris of human eye controls the light influx (iris effect), tropical anvil cirrus clouds may regulate the Earth's surface warming by controlling outgoing longwave radiation. This study examines this possible effect with monthly satellite observations such as Tropical Rainfall Measuring Mission (TRMM) precipitation, Moderate Resolution Imaging Spectroradiometer cirrus fraction, and Clouds and the Earth's Radiant Energy System top-of-the-atmosphere radiative fluxes averaged over different tropical domains from March 2000 to October 2014. To confirm that high-level cirrus is relevant to this study, Cloud-Aerosol Lidar with Orthogonal Polarization high cloud observations were also analyzed from June 2006 to December 2015. Our analysis revealed that the increase in sea surface temperature in the tropical western Pacific tends to concentrate convective cloud systems. This concentration effect very likely induces the significant reduction of both stratiform rain rate and cirrus fraction, without appreciable change in the convective rain rate. This reduction of stratiform rain rate and cirrus fraction cannot be found over its subregion or the tropical eastern Pacific, where the concentration effect of anvil cirrus is weak. Consistently, over the tropical western Pacific, the higher ratio of convective rain rate to total rain rate (i.e., precipitation efficiency) significantly correlates with warmer sea surface temperature and lower cirrus fraction. The reduced cirrus eventually increased outgoing longwave radiation to a greater degree than absorbed solar radiation. Finally, the negative relationship between precipitation efficiency and cirrus fraction tends to correspond to a low global equilibrium climate sensitivity in the models in the Coupled Model Intercomparison Project Phase 5. This suggests that tropical anvil cirrus clouds exert a negative climate feedback in strong association with precipitation efficiency.

The effect of optically thin cirrus clouds on solar radiation in Camagüey, Cuba

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B. Barja

2011-08-01

Full Text Available The effect of optically thin cirrus clouds on solar radiation is analyzed by numerical simulation, using lidar measurements of cirrus conducted at Camagüey, Cuba. Sign and amplitude of the cirrus clouds effect on solar radiation is evaluated. There is a relation between the solar zenith angle and solar cirrus cloud radiative forcing (SCRF present in the diurnal cycle of the SCRF. Maximums of SCRF out of noon located at the cirrus cloud base height are found for the thin and opaque cirrus clouds. The cirrus clouds optical depth (COD threshold for having double SCRF maximum out of noon instead of a single one at noon was 0.083. In contrast, the heating rate shows a maximum at noon in the location of cirrus clouds maximum extinction values. Cirrus clouds have a cooling effect in the solar spectrum at the Top of the Atmosphere (TOA and at the surface (SFC. The daily mean value of SCRF has an average value of −9.1 W m⁻² at TOA and −5.6 W m⁻² at SFC. The cirrus clouds also have a local heating effect on the atmospheric layer where they are located. Cirrus clouds have mean daily values of heating rates of 0.63 K day⁻¹ with a range between 0.35 K day⁻¹ and 1.24 K day⁻¹. The principal effect is in the near-infrared spectral band of the solar spectrum. There is a linear relation between SCRF and COD, with −30 W m⁻² COD⁻¹ and −26 W m⁻² COD⁻¹, values for the slopes of the fits at the TOA and SFC, respectively, in the broadband solar spectrum.

A review of the light scattering properties of cirrus

International Nuclear Information System (INIS)

Baran, Anthony J.

2009-01-01

In this review paper the light scattering properties of naturally occurring ice crystals that are found in cirrus are discussed. Cirrus, also referred to as ice crystal clouds, due to their cold temperatures, consist of a variety of non-spherical ice particles which may take on a variety of geometrical forms. These geometrical forms can range from symmetric pristine hexagonal ice columns and plates, single bullets and bullet-rosettes to non-symmetric aggregates of these shapes. These aggregates may also consist of highly complex three-dimensional structures, which may themselves consist of symmetric components. Not only does cirrus consist of a wide variety of shapes but also sizes too, and these sizes can range between <10 μm to over 1 cm. With such a variety of shapes and sizes predicting the light scattering properties from such an ensemble of ice crystals is the current challenge. This challenge is important to overcome since with cirrus being so high in the Earth's atmosphere it has an important influence on the Earth-atmosphere radiation balance and consequently adds to the uncertainty of predicting climate change. This is why it is important to represent as accurately as possible the single-scattering properties of cirrus ice crystals within general circulation models so that uncertainties in climate change predictions can be reduced. In this review paper the current measurements and observations of ice crystal size and shape are discussed and how these observations relate to current ice crystal models is reviewed. The light scattering properties of the current ice crystal models are also discussed and it is shown how space-based instruments may be used to test these models. The need for particular microphysical and space-based measurements is stressed in order to further constrain ice crystal light scattering models.

Cirrus cloud-temperature interactions over a tropical station, Gadanki from lidar and satellite observations

International Nuclear Information System (INIS)

S, Motty G; Satyanarayana, M.; Krishnakumar, V.; Dhaman, Reji k.

2014-01-01

The cirrus clouds play an important role in the radiation budget of the earth's atmospheric system and are important to characterize their vertical structure and optical properties. LIDAR measurements are obtained from the tropical station Gadanki (13.5 0 N, 79.2 0 E), India, and meteorological indicators derived from Radiosonde data. Most of the cirrus clouds are observed near to the tropopause, which substantiates the strength of the tropical convective processes. The height and temperature dependencies of cloud height, optical depth, and depolarization ratio were investigated. Cirrus observations made using CALIPSO satellite are compared with lidar data for systematic statistical study of cirrus climatology

Properties of CIRRUS Overlapping Clouds as Deduced from the GOES-12 Imagery Data

Science.gov (United States)

Chang, Fu-Lung; Minnis, Patrick; Lin, Bing; Sun-Mack, Sunny; Khaiyer, Mandana

2006-01-01

Understanding the impact of cirrus clouds on modifying both the solar reflected and terrestrial emitted radiations is crucial for climate studies. Unlike most boundary layer stratus and stratocumulus clouds that have a net cooling effect on the climate, high-level thin cirrus clouds can have a warming effect on our climate. Many research efforts have been devoted to retrieving cirrus cloud properties due to their ubiquitous presence. However, using satellite observations to detect and/or retrieve cirrus cloud properties faces two major challenges. First, they are often semitransparent at visible to infrared wavelengths; and secondly, they often occur over a lower cloud system. The overlapping of high-level cirrus and low-level stratus cloud poses a difficulty in determining the individual cloud top altitudes and optical properties, especially when the signals from cirrus clouds are overwhelmed by the signals of stratus clouds. Moreover, the operational satellite retrieval algorithms, which often assume only single layer cloud in the development of cloud retrieval techniques, cannot resolve the cloud overlapping situation properly. The new geostationary satellites, starting with the Twelfth Geostationary Operational Environmental Satellite (GOES-12), are providing a new suite of imager bands that have replaced the conventional 12-micron channel with a 13.3-micron CO2 absorption channel. The replacement of the 13.3-micron channel allows for the application of a CO2-slicing retrieval technique (Chahine et al. 1974; Smith and Platt 1978), which is one of the important passive satellite methods for remote sensing the altitudes of mid to high-level clouds. Using the CO2- slicing technique is more effective in detecting semitransparent cirrus clouds than using the conventional infrared-window method.

Monitoring cirrus cloud and tropopause height over Hanoi using a compact lidar system

International Nuclear Information System (INIS)

Bui Van Hai; Dinh Van Trung; Nguyen Xuan Tuan; Dao Duy Thang; Nguyen Thanh Binh

2012-01-01

Cirrus clouds in the upper troposphere and the lower stratosphere have attracted great attention due to their important role and impact on the atmospheric radioactive balance. Because cirrus clouds are located high in the atmosphere, their study requires a high resolution remote sensing technique not only for detection but also for the characterization of their properties. The lidar technique with its inherent high sensitivity and resolution has become an indispensable tool for studying and improving our understanding of cirrus cloud. Using lidar technique we can simultaneously measure the cloud height, thickness and follow its temporal evolution. In this paper we describe the development of a compact and highly sensitive lidar system with the aim to remotely monitor for the first time the cirrus clouds over Hanoi (2101:42 N, 10551:12 W). From the lidar data collected during the year 2011. We derive the mean cloud height, location of cloud top, the cloud mean thickness and their temporal evolution. We then compare the location of the cloud top with the position of the tropopause determined the radiosonde data and found good that the distance between cloud top and tropopause remains fairly stable, indicating that generally the top of cirrus clouds is the good tracer of the tropopause. We found that the cirrus clouds are generally located at height between 11.2 to 15 km with average height of 13.4 km. Their thickness is between 0.3 and 3.8 km with average value of 1.7 km. We also compare the properties of cirrus cloud with that observed at other locations around the world based on lidar technique. (author)

Subtropical and Polar Cirrus Clouds Characterized by Ground-Based Lidars and CALIPSO/CALIOP Observations

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Córdoba-Jabonero Carmen

2016-01-01

Full Text Available Cirrus clouds are product of weather processes, and then their occurrence and macrophysical/optical properties can vary significantly over different regions of the world. Lidars can provide height-resolved measurements with a relatively good both vertical and temporal resolutions, making them the most suitable instrumentation for high-cloud observations. The aim of this work is to show the potential of lidar observations on Cirrus clouds detection in combination with a recently proposed methodology to retrieve the Cirrus clouds macrophysical and optical features. In this sense, a few case studies of cirrus clouds observed at both subtropical and polar latitudes are examined and compared to CALIPSO/CALIOP observations. Lidar measurements are carried out in two stations: the Metropolitan city of Sao Paulo (MSP, Brazil, 23.3°S 46.4°W, located at subtropical latitudes, and the Belgrano II base (BEL, Argentina, 78ºS 35ºW in the Antarctic continent. Optical (COD-cloud optical depth and LR-Lidar Ratio and macrophysical (top/base heights and thickness properties of both the subtropical and polar cirrus clouds are reported. In general, subtropical Cirrus clouds present lower LR values and are found at higher altitudes than those detected at polar latitudes. In general, Cirrus clouds are detected at similar altitudes by CALIOP. However, a poor agreement is achieved in the LR retrieved between ground-based lidars and space-borne CALIOP measurements, likely due to the use of a fixed (or low-variable LR value in CALIOP inversion procedures.

Macrophysical and optical properties of mid-latitude cirrus clouds over a semi-arid area observed by micro-pulse lidar

International Nuclear Information System (INIS)

Wang, Jin; Zhang, Lei; Huang, Jianping; Cao, Xianjie; Liu, Ruijin; Zhou, Bi; Wang, Hongbin; Huang, Zhongwei; Bi, Jianrong; Zhou, Tian; Zhang, Beidou; Wang, Tengjiao

2013-01-01

Macrophysical and optical characteristics of cirrus clouds were investigated at the Semi-Arid Climate Observatory and Laboratory (SACOL; 35.95°N, 104.14°E) of Lanzhou University in northwest China during April to December 2007 using micro-pulse lidar data and profiling radiometer measurements. Analysis of the measurements allowed the determination of macrophysical properties such as cirrus cloud height, ambient temperature, and geometrical depth, and optical characteristics were determined in terms of optical depth, extinction coefficient, and lidar ratio. Cirrus clouds were generally observed at heights ranging from 5.8 to 12.7 km, with a mean of 9.0±1.0 km. The mean cloud geometrical depth and optical depth were found to be 2.0±0.6 km and 0.350±0.311, respectively. Optical depth increased linearly with increasing geometrical depth. The results derived from lidar signals showed that cirrus over SACOL consisted of thin cirrus and opaque cirrus which occurred frequently in the height of 8–10 km. The lidar ratio varied from 5 to 70 sr, with a mean value of 26±16 sr, after taking into account multiple scattering effects. The mean lidar ratio of thin cirrus was greater than that of opaque cirrus. The maximum lidar ratio appeared between 0.058 and 0.3 when plotted against optical depth. The lidar ratio increased exponentially as the optical depth increased. The maximum lidar ratio fell between 11 and 12 km when plotted against cloud mid-height. The lidar ratio first increased and then decreased with increasing mid-height. -- Highlights: ► Cirrus clouds over semi-arid area were firstly observed by ground-based lidar. ► Macrophysical and optical characteristics of cirrus clouds were discussed. ► Thin cirrus and opaque cirrus occurred most frequently over SACOL. ► Thin cirrus often occurred above 10 km

Microphysical properties of contrails and natural cirrus clouds

Energy Technology Data Exchange (ETDEWEB)

Strauss, B; Wendling, P [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V., Oberpfaffenhofen (Germany)

1998-12-31

The radiative properties of a condensation trail (contrail) are determined by its microphysical properties. Therefore an understanding of the concentration, size distribution, and shapes of the particles is necessary for an estimation of the climatic impact of contrails. In-situ particle measurements by use of an ice replicator are presented for several contrail and cirrus events. Contrail particles aged about 2 minutes show shapes which are nearly spherical. Typical sizes are 5 to 10 {mu}m. Concentration values reach up to the order of 1000 cm{sup -3}. Aged contrail size distributions are within the variability of those found in natural cirrus clouds. (author) 2 refs.

Microphysical properties of contrails and natural cirrus clouds

Energy Technology Data Exchange (ETDEWEB)

Strauss, B.; Wendling, P. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V., Oberpfaffenhofen (Germany)

1997-12-31

The radiative properties of a condensation trail (contrail) are determined by its microphysical properties. Therefore an understanding of the concentration, size distribution, and shapes of the particles is necessary for an estimation of the climatic impact of contrails. In-situ particle measurements by use of an ice replicator are presented for several contrail and cirrus events. Contrail particles aged about 2 minutes show shapes which are nearly spherical. Typical sizes are 5 to 10 {mu}m. Concentration values reach up to the order of 1000 cm{sup -3}. Aged contrail size distributions are within the variability of those found in natural cirrus clouds. (author) 2 refs.

A method for determination of cirrus extinction-to-backscatter ratio from CALIOP data

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Zhang Jingbin

2016-01-01

Full Text Available We are presenting an empirical equation to retrieve cirrus lidar ratio by using CALIOP 532 nm level 1 data for nighttime cases. Retrieval results have non-relationship with cirrus multiple scattering effects and not affected by the error of transmission. The average CALIPSO 532 nm cirrus lidar ratio over Longitude 120+/- 10 and Latitude 25+/-10 for whole year of 2008 are 21.66±0.06sr for the year of 2008 respectively, with the maximum bias of 9.25% for the year 2008, the results is fairly stable and reasonable.

Potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles

Science.gov (United States)

Wolf, Kevin; Ehrlich, André; Hüneke, Tilman; Pfeilsticker, Klaus; Werner, Frank; Wirth, Martin; Wendisch, Manfred

2017-03-01

Spectral radiance measurements collected in nadir and sideward viewing directions by two airborne passive solar remote sensing instruments, the Spectral Modular Airborne Radiation measurement sysTem (SMART) and the Differential Optical Absorption Spectrometer (mini-DOAS), are used to compare the remote sensing results of cirrus optical thickness τ. The comparison is based on a sensitivity study using radiative transfer simulations (RTS) and on data obtained during three airborne field campaigns: the North Atlantic Rainfall VALidation (NARVAL) mission, the Mid-Latitude Cirrus Experiment (ML-CIRRUS) and the Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems (ACRIDICON) campaign. Radiative transfer simulations are used to quantify the sensitivity of measured upward radiance I with respect to τ, ice crystal effective radius reff, viewing angle of the sensor θV, spectral surface albedo α, and ice crystal shape. From the calculations it is concluded that sideward viewing measurements are generally better suited than radiance data from the nadir direction to retrieve τ of optically thin cirrus, especially at wavelengths larger than λ = 900 nm. Using sideward instead of nadir-directed spectral radiance measurements significantly improves the sensitivity and accuracy in retrieving τ, in particular for optically thin cirrus of τ ≤ 2. The comparison of retrievals of τ based on nadir and sideward viewing radiance measurements from SMART, mini-DOAS and independent estimates of τ from an additional active remote sensing instrument, the Water Vapor Lidar Experiment in Space (WALES), shows general agreement within the range of measurement uncertainties. For the selected example a mean τ of 0.54 ± 0.2 is derived from SMART, and 0.49 ± 0.2 by mini-DOAS nadir channels, while WALES obtained a mean value of τ = 0.32 ± 0.02 at 532 nm wavelength, respectively. The mean of τ derived from the sideward viewing mini

Comparisons of cirrus cloud microphysical properties between polluted and pristine air

Science.gov (United States)

Diao, Minghui; Schumann, Ulrich; Minikin, Andreas; Jensen, Jorgen

2015-04-01

Cirrus clouds occur in the upper troposphere at altitudes where atmospheric radiative forcing is most sensitive to perturbations of water vapor concentration and water phase. The formation of cirrus clouds influences the distributions of water in both vapor and ice forms. The radiative properties of cirrus depend strongly on particle sizes. Currently it is still unclear how the formation of cirrus clouds and their microphysical properties are influenced by anthropogenic emissions (e.g., industrial emission and biomass burning). If anthropogenic emissions influence cirrus formation in a significant manner, then one should expect a systematic difference in cirrus properties between pristine (clean) air and polluted air. Because of the pollution contrasts between the Southern (SH) and Northern Hemispheres (NH), cirrus properties could have hemispheric differences as well. Therefore, we study high-resolution (~200 m), in-situ observations from two global flight campaigns: 1) the HIAPER Pole-to-Pole Observations (HIPPO) global campaign in 2009-2011 funded by the US National Science Foundation (NSF), and 2) the Interhemispheric Differences In Cirrus Properties from Anthropogenic Emissions (INCA) campaign in 2000 funded by the European Union and participating research institutions. To investigate the changes of cirrus clouds by anthropogenic emissions, we compare ice crystal distributions in polluted and pristine air, in terms of their frequency occurrence, number concentration (Nc) and mean diameter (i.e., effective-mean Deff and volume-mean Dc). Total aerosol concentration is used to represent the combined influence of natural and anthropogenic aerosols. In addition, measured carbon monoxide (CO) mixing ratio is used to discriminate between polluted and pristine air masses. All analyses are restricted to temperatures ≤ -40°C to exclude mixed-phased clouds. The HIPPO campaign observations were obtained over the North America continent and the central Pacific Ocean

Characterisation of the artificial neural network CiPS for cirrus cloud remote sensing with MSG/SEVIRI

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J. Strandgren

2017-11-01

Full Text Available Cirrus clouds remain one of the key uncertainties in atmospheric research. To better understand the properties and physical processes of cirrus clouds, accurate large-scale observations from satellites are required. Artificial neural networks (ANNs have proved to be a useful tool for cirrus cloud remote sensing. Since physics is not modelled explicitly in ANNs, a thorough characterisation of the networks is necessary. In this paper the CiPS (Cirrus Properties from SEVIRI algorithm is characterised using the space-borne lidar CALIOP. CiPS is composed of a set of ANNs for the cirrus cloud detection, opacity identification and the corresponding cloud top height, ice optical thickness and ice water path retrieval from the imager SEVIRI aboard the geostationary Meteosat Second Generation satellites. First, the retrieval accuracy is characterised with respect to different land surface types. The retrieval works best over water and vegetated surfaces, whereas a surface covered by permanent snow and ice or barren reduces the cirrus detection ability and increases the retrieval errors for the ice optical thickness and ice water path if the cirrus cloud is thin (optical thickness less than approx. 0.3. Second, the retrieval accuracy is characterised with respect to the vertical arrangement of liquid, ice clouds and aerosol layers as derived from CALIOP lidar data. The CiPS retrievals show little interference from liquid water clouds and aerosol layers below an observed cirrus cloud. A liquid water cloud vertically close or adjacent to the cirrus clearly increases the average retrieval errors for the optical thickness and ice water path, respectively, only for thin cirrus clouds with an optical thickness below 0.3 or ice water path below 5.0 g m−2. For the cloud top height retrieval, only aerosol layers affect the retrieval error, with an increased positive bias when the cirrus is at low altitudes. Third, the CiPS retrieval error is

Daytime Land Surface Temperature Extraction from MODIS Thermal Infrared Data under Cirrus Clouds

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Xiwei Fan

2015-04-01

Full Text Available Simulated data showed that cirrus clouds could lead to a maximum land surface temperature (LST retrieval error of 11.0 K when using the generalized split-window (GSW algorithm with a cirrus optical depth (COD at 0.55 μm of 0.4 and in nadir view. A correction term in the COD linear function was added to the GSW algorithm to extend the GSW algorithm to cirrus cloudy conditions. The COD was acquired by a look up table of the isolated cirrus bidirectional reflectance at 0.55 μm. Additionally, the slope k of the linear function was expressed as a multiple linear model of the top of the atmospheric brightness temperatures of MODIS channels 31–34 and as the difference between split-window channel emissivities. The simulated data showed that the LST error could be reduced from 11.0 to 2.2 K. The sensitivity analysis indicated that the total errors from all the uncertainties of input parameters, extension algorithm accuracy, and GSW algorithm accuracy were less than 2.5 K in nadir view. Finally, the Great Lakes surface water temperatures measured by buoys showed that the retrieval accuracy of the GSW algorithm was improved by at least 1.5 K using the proposed extension algorithm for cirrus skies.

Zooming in on cirrus with the Canadian Regional Climate Model

Science.gov (United States)

Stefanof, C.; Stefanof, A.; Beaulne, A.; Munoz Alpizar, R.; Szyrmer, W.; Blanchet, J.

2004-05-01

The Canadian Regional Climate Model plus a microphysical scheme: two-moments microphysics with three hydrometeor categories (cloud liquid water, pristine ice crystals and larger precipitation crystals) is used to test the simulation in forecast mode using ECMWF data at 0.4 X 0.4 degree. We are zooming in on cirrus at higher resolutions (9, 1.8, 0.36 km). We are currently using the data set measured in APEX-E3, measurements of radar, lidar, passive instruments and interpreted microphysics for some flights (G-II, C404, B200). The radar and lidar data are available for high level cirrus. The south west of Japon is the flight region. The dates are March 20, March 27 and April 2, 2003. We first focus on the March 27 frontal system. We did a rigorous synoptical analysis for the cases. The cirrus at 360 m resolution are simulated. The cloud structure and some similarities between model simulation and observations will be presented.

Single particle measurements of the chemical composition of cirrus ice residue during CRYSTAL-FACE

Science.gov (United States)

Cziczo, D. J.; Murphy, D. M.; Hudson, P. K.; Thomson, D. S.

2004-02-01

The first real-time, in situ, investigation of the chemical composition of the residue of cirrus ice crystals was performed during July 2002. This study was undertaken on a NASA WB-57F high-altitude research aircraft as part of CRYSTAL-FACE, a field campaign which sought to further our understanding of the relation of clouds, water vapor, and climate by characterizing, among other parameters, anvil cirrus formed about the Florida peninsula. A counter flow virtual impactor (CVI) was used to separate cirrus ice from the unactivated interstitial aerosol particles and evaporate condensed-phase water. Residual material, on a crystal-by-crystal basis, was subsequently analyzed using the NOAA Aeronomy Laboratory's Particle Analysis by Laser Mass Spectrometry (PALMS) instrument. Sampling was performed from 5 to 15 km altitude and from 12° to 28° north latitude within cirrus originating over land and ocean. Chemical composition measurements provided several important results. Sea salt was often incorporated into cirrus, consistent with homogeneous ice formation by aerosol particles from the marine boundary layer. Size measurements showed that large particles preferentially froze over smaller ones. Meteoritic material was found within ice crystals, indicative of a relation between stratospheric aerosol particles and tropospheric clouds. Mineral dust was the dominant residue observed in clouds formed during a dust transport event from the Sahara, consistent with a heterogeneous freezing mechanism. These results show that chemical composition and size are important determinants of which aerosol particles form cirrus ice crystals.

Simulation of idealized warm fronts and life cycles of cirrus clouds

Science.gov (United States)

Bense, Vera; Spichtinger, Peter

2013-04-01

One of the generally accepted formation mechanisms of cirrus clouds is connected to warm fronts. As the warm air glides over the cold air mass, it cools through adiabatic expansion and reaches ice supersaturation that eventually leads to the formation of ice clouds. Within this work, the EULAG model (see e.g. Prusa et al., 2008) was used to study the formation and life cycles of cirrus clouds in idealized 2-dimensional simulations. The microphysical processes were modelled with the double-moment bulk scheme of Spichtinger and Gierens (2009), which describes homogeneous and heterogeneous nucleation. In order to represent the gradual gliding of the air along the front, a ramp was chosen as topography. The sensibility of cloud formation to different environmental conditions such as wind shear, aerosol distribution and slope of the front was analyzed. In case of cirrus cloud formation its persistence after the front was studied as well as the change in microphysical properties such as ice crystal number concentrations. References: Prusa, J.M., P.K. Smolarkiewicz, A.A. Wyszogrodzki, 2008: EULAG, a computational model for multiscale flows. Computers and Fluids, doi:10.1016/j.compfluid.2007.12.001. Spichtinger, P., K. M. Gierens, 2009: Modelling of cirrus clouds - Part 1a: Model description and validation, Atmos. Chem. Phys., 9, 685-706.

Optical and geometrical properties of cirrus clouds in Amazonia derived from 1 year of ground-based lidar measurements

Science.gov (United States)

Gouveia, Diego A.; Barja, Boris; Barbosa, Henrique M. J.; Seifert, Patric; Baars, Holger; Pauliquevis, Theotonio; Artaxo, Paulo

2017-03-01

Cirrus clouds cover a large fraction of tropical latitudes and play an important role in Earth's radiation budget. Their optical properties, altitude, vertical and horizontal coverage control their radiative forcing, and hence detailed cirrus measurements at different geographical locations are of utmost importance. Studies reporting cirrus properties over tropical rain forests like the Amazon, however, are scarce. Studies with satellite profilers do not give information on the diurnal cycle, and the satellite imagers do not report on the cloud vertical structure. At the same time, ground-based lidar studies are restricted to a few case studies. In this paper, we derive the first comprehensive statistics of optical and geometrical properties of upper-tropospheric cirrus clouds in Amazonia. We used 1 year (July 2011 to June 2012) of ground-based lidar atmospheric observations north of Manaus, Brazil. This dataset was processed by an automatic cloud detection and optical properties retrieval algorithm. Upper-tropospheric cirrus clouds were observed more frequently than reported previously for tropical regions. The frequency of occurrence was found to be as high as 88 % during the wet season and not lower than 50 % during the dry season. The diurnal cycle shows a minimum around local noon and maximum during late afternoon, associated with the diurnal cycle of precipitation. The mean values of cirrus cloud top and base heights, cloud thickness, and cloud optical depth were 14.3 ± 1.9 (SD) km, 12.9 ± 2.2 km, 1.4 ± 1.1 km, and 0.25 ± 0.46, respectively. Cirrus clouds were found at temperatures down to -90 °C. Frequently cirrus were observed within the tropical tropopause layer (TTL), which are likely associated to slow mesoscale uplifting or to the remnants of overshooting convection. The vertical distribution was not uniform, and thin and subvisible cirrus occurred more frequently closer to the tropopause. The mean lidar ratio was 23.3 ± 8.0 sr. However, for

Optics and geometric characterization of cirrus from Lille lidar measurements over the period 2008-2013

International Nuclear Information System (INIS)

Nohra, R.; Parol, F.; Dubuisson

2015-01-01

The aim of this work is the detection and characterization of cirrus clouds from ground-based lidar measurements acquired at 532 nm wave length. An inversion method has been developed during this work to realize a climatologyof cirrus clouds over Lille, France (50.65°N, 3.08ºE) from 2008 to 2013. The mid-cloud height is generally observed between 7 and 13 km, and a mean thickness is found to be 1.4 ±0.8 km. Visibleclouds, characterized by anoptical thickness between 0.03 and 0.3, present 68 % of the total observed cirrus clouds. The methodology used in this work andthe retrieved geometrical and optical parameters of cirrus clouds are presented in this article. (author)

The Effect of Cirrus Clouds on Water Vapor Transport in the Upper Troposphere and Lower Stratosphere

Science.gov (United States)

Lei, L.; McCormick, M. P.; Anderson, J.

2017-12-01

Water vapor plays an important role in the Earth's radiation budget and stratospheric chemistry. It is widely accepted that a large percentage of water vapor entering the stratosphere travels through the tropical tropopause and is dehydrated by the cold tropopause temperature. The vertical transport of water vapor is also affected by the radiative effects of cirrus clouds in the tropical tropopause layer. This latter effect of cirrus clouds was investigated in this research. The work focuses on the tropical and mid-latitude region (50N-50S). Water vapor data from the Microwave Limb Sounder (MLS) and cirrus cloud data from the Cloud-Aerosol Lidar and Infrared pathfinder Satellite Observation (CALIPSO) instruments were used to investigate the relationship between the water vapor and the occurrence of cirrus cloud. A 10-degree in longitude by 10-degree in latitude resolution was chosen to bin the MLS and CALIPSO data. The result shows that the maximum water vapor in the upper troposphere (below 146 hPa) is matched very well with the highest frequency of cirrus cloud occurrences. Maximum water vapor in the lower stratosphere (100 hPa) is partly matched with the maximum cirrus cloud occurrence in the summer time. The National Oceanic and Atmospheric Administration Interpolated Outgoing Longwave Radiation data and NCEP-DOE Reanalysis 2 wind data were used also to investigate the relationship between the water vapor entering the stratosphere, deep convection, and wind. Results show that maximum water vapor at 100 hPa coincides with the northern hemisphere summer-time anticyclone. The effects from both single-layer cirrus clouds and cirrus clouds above the anvil top on the water vapor entering the stratosphere were also studied and will be presented.

Particle backscatter and relative humidity measured across cirrus clouds and comparison with microphysical cirrus modelling

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M. Brabec

2012-10-01

Full Text Available Advanced measurement and modelling techniques are employed to estimate the partitioning of atmospheric water between the gas phase and the condensed phase in and around cirrus clouds, and thus to identify in-cloud and out-of-cloud supersaturations with respect to ice. In November 2008 the newly developed balloon-borne backscatter sonde COBALD (Compact Optical Backscatter and AerosoL Detector was flown 14 times together with a CFH (Cryogenic Frost point Hygrometer from Lindenberg, Germany (52° N, 14° E. The case discussed here in detail shows two cirrus layers with in-cloud relative humidities with respect to ice between 50% and 130%. Global operational analysis data of ECMWF (roughly 1° × 1° horizontal and 1 km vertical resolution, 6-hourly stored fields fail to represent ice water contents and relative humidities. Conversely, regional COSMO-7 forecasts (6.6 km × 6.6 km, 5-min stored fields capture the measured humidities and cloud positions remarkably well. The main difference between ECMWF and COSMO data is the resolution of small-scale vertical features responsible for cirrus formation. Nevertheless, ice water contents in COSMO-7 are still off by factors 2–10, likely reflecting limitations in COSMO's ice phase bulk scheme. Significant improvements can be achieved by comprehensive size-resolved microphysical and optical modelling along backward trajectories based on COSMO-7 wind and temperature fields, which allow accurate computation of humidities, homogeneous ice nucleation, resulting ice particle size distributions and backscatter ratios at the COBALD wavelengths. However, only by superimposing small-scale temperature fluctuations, which remain unresolved by the numerical weather prediction models, can we obtain a satisfying agreement with the observations and reconcile the measured in-cloud non-equilibrium humidities with conventional ice cloud microphysics. Conversely, the model-data comparison provides no evidence that additional

16-year Climatology of Cirrus cloud properties using ground-based Lidar over Gadanki (13.45˚N, 79.18˚E)

Science.gov (United States)

Pandit, Amit Kumar; Raghunath, Karnam; Jayaraman, Achuthan; Venkat Ratnam, Madineni; Gadhavi, Harish

Cirrus clouds are ubiquitous high level cold clouds predominantly consisting of ice-crystals. With their highest coverage over the tropics, these are one of the most vital and complex components of Tropical Tropopause Layer (TTL) due to their strong radiative feedback and dehydration in upper troposphere and lower stratosphere (UTLS) regions. The continuous changes in their coverage, position, thickness, and ice-crystal size and shape distributions bring uncertainties in the estimates of cirrus cloud radiative forcing. Long-term changes in the distribution of aerosols and water vapour in the TTL can influence cirrus properties. This necessitates long-term studies of tropical cirrus clouds, which are only few. The present study provides 16-year climatology of physical and optical properties of cirrus clouds observed using a ground-based Lidar located at Gadanki (13.45(°) N, 79.18(°) ˚E and 375 m amsl) in south-India. In general, cirrus clouds occurred for about 44% of the total Lidar observation time. Owing to the increased convective activities, the occurrence of cirrus clouds during the southwest-monsoon season is highest while it is lowest during the winter. Altitude distribution of cirrus clouds reveals that the peak occurrence was about 25% at 14.5 km. The most probable base and top height of cirrus clouds are 14 and 15.5 km, respectively. This is also reflected in the bulk extinction coefficient profile (at 532 nm) of cirrus clouds. These results are compared with the CALIPSO observations. Most of the time cirrus clouds are located within the TTL bounded by convective outflow level and cold-point tropopause. Cirrus clouds are thick during the monsoon season as compared to that during winter. An inverse relation between the thickness of cirrus clouds and TTL thickness is found. The occurrence of cirrus clouds at an altitude close to the tropopause (16 km) showed an increase of 8.4% in the last 16 years. Base and top heights of cirrus clouds also showed

Validation of the large-scale Lagrangian cirrus model CLaMS-Ice by in-situ measurements

Science.gov (United States)

Costa, Anja; Rolf, Christian; Grooß, Jens-Uwe; Afchine, Armin; Spelten, Nicole; Dreiling, Volker; Zöger, Martin; Krämer, Martina

2015-04-01

Cirrus clouds are an element of uncertainty in the climate system and have received increasing attention since the last IPCC reports. The interaction of varying freezing meachanisms, sedimentation rates, temperature and updraft velocity fluctuations and other factors that lead to the formation of those clouds is still not fully understood. During the ML-Cirrus campaign 2014 (Germany), the new cirrus cloud model CLaMS-Ice (see Rolf et al., EGU 2015) has been used for flight planning to direct the research aircraft HALO into interesting cirrus cloud regions. Now, after the campaign, we use our in-situ aircraft measurements to validate and improve this model - with the long-term goal to enable it to simulate cirrus cloud cover globally, with reasonable computing times and sufficient accuracy. CLaMS-Ice consists of a two-moment bulk model established by Spichtinger and Gierens (2009a, 2009b), which simulates cirrus clouds along trajectories that the Lagrangian model CLaMS (McKenna et al., 2002 and Konopka et al. 2007) derived from ECMWF data. The model output covers temperature, pressure, relative humidity, ice water content (IWC), and ice crystal numbers (Nice). These parameters were measured on board of HALO by the following instruments: temperature and pressure by BAHAMAS, total and gas phase water by the hygrometers FISH and SHARC (see Meyer et al 2014, submitted to ACP), and Nice as well as ice crystal size distributions by the cloud spectrometer NIXE-CAPS (see also Krämer et al., EGU 2015). Comparisons of the model results with the measurements yield that cirrus clouds can be successfully simulated by CLaMS-Ice. However, there are sections in which the model's relative humidity and Nice deviate considerably from the measured values. This can be traced back to e.g. the initialization of total water from ECMWF data. The simulations are therefore reinitiated with the total water content measured by FISH. Other possible sources of uncertainties are investigated, as

Midlatitude Cirrus Clouds Derived from Hurricane Nora: A Case Study with Implications for Ice Crystal Nucleation and Shape.

Science.gov (United States)

Sassen, Kenneth; Arnott, W. Patrick; O'C. Starr, David; Mace, Gerald G.; Wang, Zhien; Poellot, Michael R.

2003-04-01

Hurricane Nora traveled up the Baja Peninsula coast in the unusually warm El Niño waters of September 1997 until rapidly decaying as it approached southern California on 24 September. The anvil cirrus blowoff from the final surge of tropical convection became embedded in subtropical flow that advected the cirrus across the western United States, where it was studied from the Facility for Atmospheric Remote Sensing (FARS) in Salt Lake City, Utah, on 25 September. A day later, the cirrus shield remnants were redirected southward by midlatitude circulations into the southern Great Plains, providing a case study opportunity for the research aircraft and ground-based remote sensors assembled at the Clouds and Radiation Testbed (CART) site in northern Oklahoma. Using these comprehensive resources and new remote sensing cloud retrieval algorithms, the microphysical and radiative cloud properties of this unusual cirrus event are uniquely characterized.Importantly, at both the FARS and CART sites the cirrus generated spectacular halos and arcs, which acted as a tracer for the hurricane cirrus, despite the limited lifetimes of individual ice crystals. Lidar depolarization data indicate widespread regions of uniform ice plate orientations, and in situ particle replicator data show a preponderance of pristine, solid hexagonal plates and columns. It is suggested that these unusual aspects are the result of the mode of cirrus particle nucleation, presumably involving the lofting of sea salt nuclei in strong thunderstorm updrafts into the upper troposphere. This created a reservoir of haze particles that continued to produce halide-salt-contaminated ice crystals during the extended period of cirrus cloud maintenance. The inference that marine microbiota are embedded in the replicas of some ice crystals collected over the CART site points to the longevity of marine effects. Various nucleation scenarios proposed for cirrus clouds based on this and other studies, and the

Ice nucleation and cloud microphysical properties in tropical tropopause layer cirrus

Directory of Open Access Journals (Sweden)

E. J. Jensen

2010-02-01

Full Text Available In past modeling studies, it has generally been assumed that the predominant mechanism for nucleation of ice in the uppermost troposphere is homogeneous freezing of aqueous aerosols. However, recent in situ and remote-sensing measurements of the properties of cirrus clouds at very low temperatures in the tropical tropopause layer (TTL are broadly inconsistent with theoretial predictions based on the homogeneous freezing assumption. The nearly ubiquitous occurence of gravity waves in the TTL makes the predictions from homogeneous nucleation theory particularly difficult to reconcile with measurements. These measured properties include ice number concentrations, which are much lower than theory predicts; ice crystal size distributions, which are much broader than theory predicts; and cloud extinctions, which are much lower than theory predicts. Although other explanations are possible, one way to limit ice concentrations is to have on the order of 50 L⁻¹ effective ice nuclei (IN that could nucleate ice at relatively low supersaturations. We suggest that ammonium sulfate particles, which would be dry much of the time in the cold TTL, are a potential IN candidate for TTL cirrus. However, this mechanism remains to be fully quantified for the size distribution of ammonium sulfate (possibly internally mixed with organics actually present in the upper troposphere. Possible implications of the observed cloud microphysical properties for ice sedimentation, dehydration, and cloud persistence are also discussed.

CSIR NLC mobile lidar observation of cirrus cloud

CSIR Research Space (South Africa)

Sivakumar, V

2011-09-01

Full Text Available In this paper, the authors present a night-time continuous CSIR-NLC mobile observation of highaltitude cirrus cloud. The LIDAR measurements will also elucidate the aerosol concentration, optical depth, cloud position, thickness and other general...

The Dependence of Cirrus Gamma Size Distributions Expressed as Volumes in N(sub 0)-Lambda-Mu Phase Space and Bulk Cloud Properties on Environmental Conditions: Results from the Small Ice Particles in Cirrus Experiment (SPARTICUS)

Science.gov (United States)

Jackson, Robert C.; McFarquhar, Greg M.; Fridlind, Ann M.; Atlas, Rachel

2015-01-01

The variability of cirrus ice microphysical properties is investigated using observations obtained during the Small Particles in Cirrus (SPARTICUS) campaign. An existing approach that represents a size distribution (SD) as a single gamma function using an ellipsoid of equally realizable solutions in (N(sub 0), lambda, mu) phase space is modified to automatically identify multiple modes in SDs and characterize each mode by such an ellipsoid. The modified approach is applied to ice crystals with maximum dimension D greater than15 micrometers collected by the 2-D stereo and 2-D precipitation probes on the Stratton Park Engineering Company Learjet. The dependencies of N(sub 0), mu, and lambda from each mode, total number concentration, bulk extinction, ice water content (IWC), and mass median maximum dimension D(sub mm) as a function of temperature T and cirrus type are then analyzed. The changes in the observed codependencies between N(sub 0), mu, and lambda, bulk extinction, IWC, and D(sub mm) with environmental conditions indicate that particles were larger at higher T during SPARTICUS. At most two modes were observed in any SD during SPARTICUS, with the average boundary between them at 115 micrometers, similar to past studies not using probes with shatter mitigating tips and artifact removal algorithms. The bimodality of the SDs increased with T. This and the differences in N(sub 0), mu, and lambda between the modes suggest that particles with smaller D nucleated more recently than particles with larger D, which grew via vapor deposition and aggregation. Because smaller crystals, whose concentrations are uncertain, make marginal contributions to higher order moments, the use of higher moments for evaluating model fields is suggested.

Comparing Gonioscopy With Visante and Cirrus Optical Coherence Tomography for Anterior Chamber Angle Assessment in Glaucoma Patients.

Science.gov (United States)

Hu, Cindy X; Mantravadi, Anand; Zangalli, Camila; Ali, Mohsin; Faria, Bruno M; Richman, Jesse; Wizov, Sheryl S; Razeghinejad, M Reza; Moster, Marlene R; Katz, L Jay

2016-02-01

The aim of this study was to compare gonioscopy with Visante and Cirrus optical coherence tomography (OCT) for identifying angle structures and the presence of angle closure in patients with glaucoma. A secondary objective was to assess interrater agreement for gonioscopy grading among 3 independent examiners. Gonioscopy grading using Spaeth Classification and determination of angle-closure risk was performed on 1 randomly selected eye for 50 phakic patients. Images of the same eye using both Visante and Cirrus OCT were obtained in both light and dark conditions. Agreement of angle closure among 3 devices and interrater agreement for gonioscopy were determined using Cohen's κ (K) or Kendall's coefficient of concordance (W). Of the 50 patients, 60% were female, 64% were white, and the mean age was 62 years. Angle closure was detected in 18%, 16%, and 48% of quadrants with Visante, Cirrus, and gonioscopy, respectively. The scleral spur was identified in 56% and 50% of quadrants with Visante and Cirrus OCT, respectively. Visante and Cirrus OCT showed moderate agreement in detecting angle closure (K=0.42 light, K=0.53 dark) but slight-to-fair agreement with gonioscopy (Visante K=0.25, Cirrus K=0.15). Gonioscopy demonstrated substantial agreement in angle closure (K=0.65 to 0.68) and angle-closure risk assessment (W=0.83) among 3 examiners. Visante and Cirrus OCT imaging may have limited ability to identify angle closure because of difficulty identifying angle structures. Gonioscopy by well-trained clinicians had remarkably consistent agreement for identifying angle-closure risk.

Modeling of Cloud/Radiation Processes for Cirrus Cloud Formation

National Research Council Canada - National Science Library

Liou, K

1997-01-01

This technical report includes five reprints and pre-prints of papers associated with the modeling of cirrus cloud and radiation processes as well as remote sensing of cloud optical and microphysical...

Evidence of impact of aviation on cirrus cloud formation

Directory of Open Access Journals (Sweden)

C. S. Zerefos

2003-01-01

Full Text Available This work examines changes in cirrus cloud cover (CCC in possible association with aviation activities at congested air corridors. The analysis is based on the latest version of the International Satellite Cloud Climatology Project D2 data set and covers the period 1984-1998. Over the studied areas, the effect of large-scale modes of natural climate variability such as ENSO, QBO and NAO as well as the possible influence of the tropopause variability, were first removed from the cloud data set in order to calculate long-term changes of observed cirrus cloudiness. The results show increasing trends in (CCC between 1984 and 1998 over the high air traffic corridors of North America, North Atlantic and Europe. Of these upward trends, only in the summertime over the North Atlantic and only in the wintertime over North America are statistically significant (exceeding +2.0% per decade. Over adjacent locations with low air traffic, the calculated trends are statistically insignificant and in most cases negative both during winter and summer in the regions studied. These negative trends, over low air traffic regions, are consistent with the observed large scale negative trends seen in (CCC over most of the northern middle latitudes and over the tropics. Moreover, further investigation of vertical velocities over high and low air traffic regions provide evidence that the trends of opposite signs in (CCC over these regions, do not seem to be caused by different trends in dynamics. It is also shown that the longitudinal distribution of decadal changes in (CCC along the latitude belt centered at the North Atlantic air corridor, parallels the spatial distribution of fuel consumption from highflying air traffic, providing an independent test of possible impact of aviation on contrail cirrus formation. The correlation between the fuel consumption and the longitudinal variability of (CCC is significant (+0.7 over the middle latitudes but not over the tropics

Lidar inelastic multiple-scattering parameters of cirrus particle ensembles determined with geometrical-optics crystal phase functions.

Science.gov (United States)

Reichardt, J; Hess, M; Macke, A

2000-04-20

Multiple-scattering correction factors for cirrus particle extinction coefficients measured with Raman and high spectral resolution lidars are calculated with a radiative-transfer model. Cirrus particle-ensemble phase functions are computed from single-crystal phase functions derived in a geometrical-optics approximation. Seven crystal types are considered. In cirrus clouds with height-independent particle extinction coefficients the general pattern of the multiple-scattering parameters has a steep onset at cloud base with values of 0.5-0.7 followed by a gradual and monotonic decrease to 0.1-0.2 at cloud top. The larger the scattering particles are, the more gradual is the rate of decrease. Multiple-scattering parameters of complex crystals and of imperfect hexagonal columns and plates can be well approximated by those of projected-area equivalent ice spheres, whereas perfect hexagonal crystals show values as much as 70% higher than those of spheres. The dependencies of the multiple-scattering parameters on cirrus particle spectrum, base height, and geometric depth and on the lidar parameters laser wavelength and receiver field of view, are discussed, and a set of multiple-scattering parameter profiles for the correction of extinction measurements in homogeneous cirrus is provided.

Statistics of optical and geometrical properties of cirrus cloud over tibetan plateau measured by lidar and radiosonde

Directory of Open Access Journals (Sweden)

Dai Guangyao

2018-01-01

Full Text Available Cirrus clouds affect the energy budget and hydrological cycle of the earth’s atmosphere. The Tibetan Plateau (TP plays a significant role in the global and regional climate. Optical and geometrical properties of cirrus clouds in the TP were measured in July-August 2014 by lidar and radiosonde. The statistics and temperature dependences of the corresponding properties are analyzed. The cirrus cloud formations are discussed with respect to temperature deviation and dynamic processes.

Comparisons of cirrus cloud properties between polluted and pristine air based on in-situ observations from the NSF HIPPO, EU INCA and NASA ATTREX campaigns

Science.gov (United States)

Diao, M.; Schumann, U.; Jensen, J. B.; Minikin, A.

2015-12-01

The radiative forcing of cirrus clouds is influenced by microphysical (e.g., ice crystal number concentration and size distribution) and macroscopic properties. Currently it is still unclear how the formation of cirrus clouds and their microphysical properties are influenced by anthropogenic emissions. In this work, we use airborne in-situ observations to compare cirrus cloud properties between polluted and pristine regions. Our dataset includes: the NSF HIAPER Pole-to-Pole Observations (HIPPO) Global campaign (2009-2011), the EU Interhemispheric Differences In Cirrus Properties from Anthropogenic Emissions (INCA) campaign (2000) and the NASA Airborne Tropical Tropopause Experiment (ATTREX) campaign (2014). The combined dataset include observations of both extratropical (HIPPO and INCA) and tropical (ATTREX) cirrus, over the Northern and Southern Hemispheres. We use the in-situ measured carbon monoxide (CO) mixing ratio as a pollution indicator, and compare ice microphysical properties (i.e., ice crystal number concentration (Nc) and number-weighted mean diameter (Dc)) between air masses with higher and lower CO. All analyses are restricted to T ≤ -40°C. By analyzing ice crystals (Fast-2DC, 87.5-1600 µm) in HIPPO, we found that Dc decreases with increasing CO concentration at multiple constant pressure levels. In addition, analysis of INCA data shows that Nc and extinction of small ice particles (FSSP 3-20 µm) increases with increasing CO. Particles < 87.5 µm in Fast-2DC data are not considered due to uncertainty in sample volume, and the FSSP measurements are subject to possible shattering. We further analyze the ice crystals (SPEC FCDP, 1-50 µm) in the tropical tropopause layer in ATTREX. At -70°C to -90°C, we found that the average Nc (Dc) increases (decreases) at higher CO. Overall, our results suggest that extratropical and tropical cirrus are likely to have more numerous small ice particles, when sampled in the more polluted background. Back

Clarifying the dominant sources and mechanisms of cirrus cloud formation.

Science.gov (United States)

Cziczo, Daniel J; Froyd, Karl D; Hoose, Corinna; Jensen, Eric J; Diao, Minghui; Zondlo, Mark A; Smith, Jessica B; Twohy, Cynthia H; Murphy, Daniel M

2013-06-14

Formation of cirrus clouds depends on the availability of ice nuclei to begin condensation of atmospheric water vapor. Although it is known that only a small fraction of atmospheric aerosols are efficient ice nuclei, the critical ingredients that make those aerosols so effective have not been established. We have determined in situ the composition of the residual particles within cirrus crystals after the ice was sublimated. Our results demonstrate that mineral dust and metallic particles are the dominant source of residual particles, whereas sulfate and organic particles are underrepresented, and elemental carbon and biological materials are essentially absent. Further, composition analysis combined with relative humidity measurements suggests that heterogeneous freezing was the dominant formation mechanism of these clouds.

Long-term trend analysis and climatology of tropical cirrus clouds using 16 years of lidar data set over Southern India

Science.gov (United States)

Pandit, A. K.; Gadhavi, H. S.; Venkat Ratnam, M.; Raghunath, K.; Rao, S. V. B.; Jayaraman, A.

2015-12-01

Sixteen-year (1998-2013) climatology of cirrus clouds and their macrophysical (base height, top height and geometrical thickness) and optical properties (cloud optical thickness) observed using a ground-based lidar over Gadanki (13.5° N, 79.2° E), India, is presented. The climatology obtained from the ground-based lidar is compared with the climatology obtained from 7 and a half years (June 2006-December 2013) of Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations. A very good agreement is found between the two climatologies in spite of their opposite viewing geometries and the differences in sampling frequencies. Nearly 50-55 % of cirrus clouds were found to possess geometrical thickness less than 2 km. Ground-based lidar is found to detect a higher number of sub-visible clouds than CALIOP which has implications for global warming studies as sub-visible cirrus clouds have significant positive radiative forcing. Cirrus clouds with mid-cloud temperatures between -50 to -70 °C have a mean geometrical thickness greater than 2 km in contrast to the earlier reported value of 1.7 km. Trend analyses reveal a statistically significant increase in the altitude of sub-visible cirrus clouds which is consistent with the recent climate model simulations. The mid-cloud altitude of sub-visible cirrus clouds is found to be increasing at the rate of 41 ± 21 m year-1. Statistically significant decrease in optical thickness of sub-visible and thick cirrus clouds is observed. Also, the fraction of sub-visible cirrus cloud is found to have increased by 9 % in the last 16 years (1998 to 2013). This increase is mainly compensated by a 7 % decrease in thin cirrus cloud fraction. This has implications for the temperature and water vapour budget in the tropical tropopause layer.

Technical note: A new day- and night-time Meteosat Second Generation Cirrus Detection Algorithm MeCiDA

Directory of Open Access Journals (Sweden)

W. Krebs

2007-12-01

Full Text Available A new cirrus detection algorithm for the Spinning Enhanced Visible and Infra-Red Imager (SEVIRI aboard the geostationary Meteosat Second Generation (MSG, MeCiDA, is presented. The algorithm uses the seven infrared channels of SEVIRI and thus provides a consistent scheme for cirrus detection at day and night. MeCiDA combines morphological and multi-spectral threshold tests and detects optically thick and thin ice clouds. The thresholds were determined by a comprehensive theoretical study using radiative transfer simulations for various atmospheric situations as well as by manually evaluating actual satellite observations. The cirrus detection has been optimized for mid- and high latitudes but it could be adapted to other regions as well. The retrieved cirrus masks have been validated by comparison with the Moderate Resolution Imaging Spectroradiometer (MODIS Cirrus Reflection Flag. To study possible seasonal variations in the performance of the algorithm, one scene per month of the year 2004 was randomly selected and compared with the MODIS flag. 81% of the pixels were classified identically by both algorithms. In a comparison of monthly mean values for Europe and the North-Atlantic MeCiDA detected 29.3% cirrus coverage, while the MODIS SWIR cirrus coverage was 38.1%. A lower detection efficiency is to be expected for MeCiDA, as the spatial resolution of MODIS is considerably better and as we used only the thermal infrared channels in contrast to the MODIS algorithm which uses infrared and visible radiances. The advantage of MeCiDA compared to retrievals for polar orbiting instruments or previous geostationary satellites is that it permits the derivation of quantitative data every 15 min, 24 h a day. This high temporal resolution allows the study of diurnal variations and life cycle aspects. MeCiDA is fast enough for near real-time applications.

Comparison and interchangeability of macular thickness measured with Cirrus OCT and Stratus OCT in myopic eyes

Directory of Open Access Journals (Sweden)

Geng Wang

2015-12-01

Full Text Available AIM: To investigate the difference of macular thickness measurements between stratus optical coherence tomography (OCT and Cirrus OCT (Carl Zeiss Meditec, Dublin, CA, USA in the same myopic patient and to develop a conversion equation to interchange macular thickness obtained with these two OCT devices. METHODS: Eighty-nine healthy Chinese adults with spherical equivalent (SE ranging from -1.13 D to -9.63 D were recruited. The macular thickness was measured by Cirrus OCT and Stratus OCT. The correlation between macular thickness and axial length and the agreement between two OCT measurements were evaluated. A formula was generated to interchange macular thickness obtained with two OCT devices. RESULTS: Average macular thickness measured with Stratus OCT (r=-0.280, P=0.008 and Cirrus OCT (r=-0.224, P=0.034 were found to be negatively correlated with axial length. No statistically significant correlation was found between axial length and central subfield macular thickness (CMT measured with Stratus OCT (r=0.191, P=0.073 and Cirrus OCT (r=0.169, P=0.113. The mean CMT measured with Cirrus OCT was 53.63±7.94 μm thicker than with Stratus OCT. The formula CMTCirrus OCT=78.328+0.874×CMTStratus OCT was generated to interchange macular thickness obtained with two OCT devices. CONCLUSION: Macular thickness measured with Cirrus OCT were thicker than with Stratus OCT in myopic eyes. A formula can be used to interchange macular thickness measured with two OCT devices in myopic eyes. Studies with different OCT devices and larger samples are warranted to enable the comparison of macular values measured with different OCT devices.

Climate impact of anthropogenic aerosols on cirrus clouds

Science.gov (United States)

Penner, J.; Zhou, C.

2017-12-01

Cirrus clouds have a net warming effect on the atmosphere and cover about 30% of the Earth's area. Aerosol particles initiate ice formation in the upper troposphere through modes of action that include homogeneous freezing of solution droplets, heterogeneous nucleation on solid particles immersed in a solution, and deposition nucleation of vapor onto solid particles. However, the efficacy with which particles act to form cirrus particles in a model depends on the representation of updrafts. Here, we use a representation of updrafts based on observations of gravity waves, and follow ice formation/evaporation during both updrafts and downdrafts. We examine the possible change in ice number concentration from anthropogenic soot originating from surface sources of fossil fuel and biomass burning and from aircraft particles that have previously formed ice in contrails. Results show that fossil fuel and biomass burning soot aerosols with this version exert a radiative forcing of -0.15±0.02 Wm-2 while aircraft aerosols that have been pre-activated within contrails exert a forcing of -0.20±0.06 Wm-2, but it is possible to decrease these estimates of forcing if a larger fraction of dust particles act as heterogeneous ice nuclei. In addition aircraft aerosols may warm the climate if a large fraction of these particles act as ice nuclei. The magnitude of the forcing in cirrus clouds can be comparable to the forcing exerted by anthropogenic aerosols on warm clouds. This assessment could therefore support climate models with high sensitivity to greenhouse gas forcing, while still allowing the models to fit the overall historical temperature change.

Radiative-dynamical and microphysical processes of thin cirrus clouds controlling humidity of air entering the stratosphere

Science.gov (United States)

Dinh, Tra; Fueglistaler, Stephan

2016-04-01

Thin cirrus clouds in the tropical tropopause layer (TTL) are of great interest due to their role in the control of water vapor and temperature in the TTL. Previous research on TTL cirrus clouds has focussed mainly on microphysical processes, specifically the ice nucleation mechanism and dehydration efficiency. Here, we use a cloud resolving model to analyse the sensitivity of TTL cirrus characteristics and impacts with respect to microphysical and radiative processes. A steady-state TTL cirrus cloud field is obtained in the model forced with dynamical conditions typical for the TTL (2-dimensional setup with a Kelvin-wave temperature perturbation). Our model results show that the dehydration efficiency (as given by the domain average relative humidity in the layer of cloud occurrence) is relatively insensitive to the ice nucleation mechanism, i.e. homogeneous versus heterogeneous nucleation. Rather, TTL cirrus affect the water vapor entering the stratosphere via an indirect effect associated with the cloud radiative heating and dynamics. Resolving the cloud radiative heating and the radiatively induced circulations approximately doubles the domain average ice mass. The cloud radiative heating is proportional to the domain average ice mass, and the observed increase in domain average ice mass induces a domain average temperature increase of a few Kelvin. The corresponding increase in water vapor entering the stratosphere is estimated to be about 30 to 40%.

Corona-producing ice clouds: A case study of a cold mid-latitude cirrus layer

International Nuclear Information System (INIS)

Sassen, K.; Mace, G.G.; Hallett, J.; Poellot, M.R.

1998-01-01

A high (14.0-km), cold (-71.0thinsp degree C) cirrus cloud was studied by ground-based polarization lidar and millimeter radar and aircraft probes on the night of 19 April 1994 from the Cloud and Radiation Testbed site in northern Oklahoma. A rare cirrus cloud lunar corona was generated by this 1 - 2-km-deep cloud, thus providing an opportunity to measure the composition in situ, which had previously been assumed only on the basis of lidar depolarization data and simple diffraction theory for spheres. In this case, corona ring analysis indicated an effective particle diameter of ∼22 μm. A variety of in situ data corroborates the approximate ice-particle size derived from the passive retrieval method, especially near the cloud top, where impacted cloud samples show simple solid crystals. The homogeneous freezing of sulfuric acid droplets of stratospheric origin is assumed to be the dominant ice-particle nucleation mode acting in corona-producing cirrus clouds. It is speculated that this process results in a previously unrecognized mode of acid-contaminated ice-particle growth and that such small-particle cold cirrus clouds are potentially a radiatively distinct type of cloud. copyright 1998 Optical Society of America

Far-infrared Spectral Radiance Observations and Modeling of Arctic Cirrus: Preliminary Results From RHUBC

Science.gov (United States)

Humpage, Neil; Green, Paul D.; Harries, John E.

2009-03-01

Recent studies have highlighted the important contribution of the far-infrared (electromagnetic radiation with wavelengths greater than 12 μm) to the Earth's radiative energy budget. In a cloud-free atmosphere, a significant fraction of the Earth's cooling to space from the mid- and upper troposphere takes place via the water vapor pure rotational band between 17 and 33 μm. Cirrus clouds also play an important role in the Earth's outgoing longwave radiation. The effect of cirrus on far-infrared radiation is of particular interest, since the refractive index of ice depends strongly on wavelength in this spectral region. The scattering properties of ice crystals are directly related to the refractive index, so consequently the spectral signature of cirrus measured in the FIR is sensitive to the cloud microphysical properties [1, 2]. By examining radiances measured at wavelengths between the strong water vapor absorption lines in the FIR, the understanding of the relationship between cirrus microphysics and the radiative transfer of thermal energy through cirrus may be improved. Until recently, very few observations of FIR spectral radiances had been made. The Tropospheric Airborne Fourier Transform Spectrometer (TAFTS) was developed by Imperial College to address this lack of observational data. TAFTS observes both zenith and nadir radiances at 0.1 cm-1 resolution, between 80 and 600 cm-1. During February and March 2007, TAFTS was involved in RHUBC (the Radiative Heating in Under-explored Bands Campaign), an ARM funded field campaign based at the ACRF-North Slope of Alaska site near Barrow, situated at 71° latitude. Infrared zenith spectral observations were taken by both TAFTS and the AERI-ER (spectral range 400-3300 cm-1) from the ground during both cloud-free and cirrus conditions. A wide range of other instrumentation was also available at the site, including a micropulse lidar, 35 GHz radar and the University of Colorado/NOAA Ground-based Scanning Radiometer

A case study of formation and maintenance of a lower stratospheric cirrus cloud over the tropics

Directory of Open Access Journals (Sweden)

M. Sandhya

2015-05-01

Full Text Available A rare occurrence of stratospheric cirrus at 18.6 km height persisting for about 5 days during 3–7 March 2014 is inferred from the ground-based Mie lidar observations over Gadanki (13.5° N, 79.2° E and spaceborne observations. Due to the vertical transport by large updrafts on 3 March in the troposphere, triggered by a potential vorticity intrusion, the water vapour mixing ratio shows an increase around the height of 18.6 km. Relative humidity with respect to ice is ~ 150%, indicating that the cirrus cloud may be formed though homogeneous nucleation of sulfuric acid. The cirrus cloud persists due to the cold anomaly associated with the presence of a 4-day wave.

3D reconstruction of tropospheric cirrus clouds by stereovision system

Science.gov (United States)

Nadjib Kouahla, Mohamed; Moreels, Guy; Seridi, Hamid

2016-07-01

A stereo imaging method is applied to measure the altitude of cirrus clouds and provide a 3D map of the altitude of the layer centroid. They are located in the high troposphere and, sometimes in the lower stratosphere, between 6 and 10 km high. Two simultaneous images of the same scene are taken with Canon cameras (400D) in two sites distant of 37 Km. Each image processed in order to invert the perspective effect and provide a satellite-type view of the layer. Pairs of matched points that correspond to a physical emissive point in the common area are identified in calculating a correlation coefficient (ZNCC: Zero mean Normalized Cross-correlation or ZSSD: as Zero mean Sum of Squared Differences). This method is suitable for obtaining 3D representations in the case of low-contrast objects. An observational campaign was conducted in June 2014 in France. The images were taken simultaneously at Marnay (47°17'31.5" N, 5°44'58.8" E; altitude 275 m) 25 km northwest of Besancon and in Mont poupet (46°58'31.5" N, 5°52'22.7" E; altitude 600 m) southwest of Besancon at 43 km. 3D maps of the Natural cirrus clouds and artificial like "aircraft trails" are retrieved. They are compared with pseudo-relief intensity maps of the same region. The mean altitude of the cirrus barycenter is located at 8.5 ± 1km on June 11.

Validation of POLDER/ADEOS data using a ground-based lidar network: Preliminary results for semi-transparent and cirrus clouds

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Chepfer, H.; Sauvage, L.; Flamant, P. H.; Pelon, J.; Goloub, P.; Brogniez, G.; spinhirne, J.; Lavorato, M.; Sugimoto, N.

1998-01-01

At mid and tropical latitudes, cirrus clouds are present more than 50% of the time in satellites observations. Due to their large spatial and temporal coverage, and associated low temperatures, cirrus clouds have a major influence on the Earth-Ocean-Atmosphere energy balance through their effects on the incoming solar radiation and outgoing infrared radiation. At present the impact of cirrus clouds on climate is well recognized but remains to be asserted more precisely, for their optical and radiative properties are not very well known. In order to understand the effects of cirrus clouds on climate, their optical and radiative characteristics of these clouds need to be determined accurately at different scales in different locations i.e. latitude. Lidars are well suited to observe cirrus clouds, they can detect very thin and semi-transparent layers, and retrieve the clouds geometrical properties i.e. altitude and multilayers, as well as radiative properties i.e. optical depth, backscattering phase functions of ice crystals. Moreover the linear depolarization ratio can give information on the ice crystal shape. In addition, the data collected with an airborne version of POLDER (POLarization and Directionality of Earth Reflectances) instrument have shown that bidirectional polarized measurements can provide information on cirrus cloud microphysical properties (crystal shapes, preferred orientation in space). The spaceborne version of POLDER-1 has been flown on ADEOS-1 platform during 8 months (October 96 - June 97), and the next POLDER-2 instrument will be launched in 2000 on ADEOS-2. The POLDER-1 cloud inversion algorithms are currently under validation. For cirrus clouds, a validation based on comparisons between cloud properties retrieved from POLDER-1 data and cloud properties inferred from a ground-based lidar network is currently under consideration. We present the first results of the validation.

Influences of cloud heterogeneity on cirrus optical properties retrieved from the visible and near-infrared channels of MODIS/SEVIRI for flat and optically thick cirrus clouds

International Nuclear Information System (INIS)

Zhou, Yongbo; Sun, Xuejin; Zhang, Riwei; Zhang, Chuanliang; Li, Haoran; Zhou, Junhao; Li, Shaohui

2017-01-01

The influences of three-dimensional radiative effects and horizontal heterogeneity effects on the retrieval of cloud optical thickness (COT) and effective diameter (De) for cirrus clouds are explored by the SHDOM radiative transfer model. The stochastic cirrus clouds are generated by the Cloudgen model based on the Atmospheric Radiation Measurement program data. Incorporating a new ice cloud spectral model, we evaluate the retrieval errors for two solar zenith angles (SZAs) (30° and 60°), four solar azimuth angles (0°, 45°, 90°, and 180°), and two sensor settings (Moderate Resolution Imaging Spectrometer (MODIS) onboard Aqua and Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard METEOSAT-8). The domain-averaged relative error of COT (μ) ranges from −24.1 % to -1.0 % (SZA = 30°) and from −11.6 % to 3.3 % (SZA = 60°), with the uncertainty within 7.5 % to –12.5 % (SZA = 30°) and 20.0 % - 27.5 % (SZA = 60°). For the SZA of 60° only, the relative error and uncertainty are parameterized by the retrieved COT by linear functions, providing bases to correct the retrieved COT and estimate their uncertainties. Besides, De is overestimated by 0.7–15.0 μm on the domain average, with the corresponding uncertainty within 6.7–26.5 μm. The retrieval errors show no discernible dependence on solar azimuth angle due to the flat tops and full coverage of the cirrus samples. The results are valid only for the two samples and for the specific spatial resolution of the radiative transfer simulations. - Highlights: • The retrieved cloud optical properties for 3-D cirrus clouds are evaluated. • The cloud optical thickness and uncertainty could be corrected and estimated. • On the domain average, the effective diameter of ice crystal is overestimated. • The optical properties show non-obvious dependence on the solar azimuth angle.

What is the role of laminar cirrus cloud on regulating the cross-tropopause water vapor transport?

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Wu, D. L.; Gong, J.; Tsai, V.

2016-12-01

Laminar cirrus is an extremely thin ice cloud found persistently inhabit in the tropical and subtropical tropopause. Due to its sub-visible optical depth and high formation altitude, knowledge about the characteristics of this special type of cloud is very limited, and debates are ongoing about its role on regulating the cross-tropopause transport of water vapor. The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO satellite has been continuously providing us with unprecedented details of the laminar cirrus since its launch in 2006. In this research, we adapted Winker and Trepte (1998)'s eyeball detection method. A JAVA-based applet and graphical user interface (GUI) is developed to manually select the laminar, which then automatically record the cloud properties, such as spatial location, shape, thickness, tilt angle, and whether its isolated or directly above a deep convective cloud. Monthly statistics of the laminar cirrus are then separately analyzed according to the orbit node, isolated/convective, banded/non-banded, etc. Monthly statistics support a diurnal difference in the occurring frequency and formation height of the laminar cirrus. Also, isolated and convective laminars show diverse behaviors (height, location, distribution, etc.), which strongly implies that their formation mechanisms and their roles on depleting the upper troposphere water vapor are distinct. We further study the relationship between laminar characteristics and collocated and coincident water vapor gradient measurements from Aura Microwave Limb Sounder (MLS) observations below and above the laminars. The identified relationship provides a quantitative answer to the role laminar cirrus plays on regulating the water vapor entering the stratosphere.

Simulating gas-aerosol-cirrus interactions: Process-oriented microphysical model and applications

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B. Kärcher

2003-01-01

Full Text Available This work describes a process-oriented, microphysical-chemical model to simulate the formation and evolution of aerosols and ice crystals under the conditions prevailing in the upper troposphere and lower stratosphere. The model can be run as a box model or along atmospheric trajectories, and considers mixing, gas phase chemistry of aerosol precursors, binary homogeneous aerosol nucleation, homogeneous and heterogeneous ice nucleation, coagulation, condensation and dissolution, gas retention during particle freezing, gas trapping in growing ice crystals, and reverse processes. Chemical equations are solved iteratively using a second order implicit integration method. Gas-particle interactions and coagulation are treated over various size structures, with fully mass conserving and non-iterative numerical solution schemes. Particle types include quinternary aqueous solutions composed of H2SO4, HNO3, HCl, and HBr with and without insoluble components, insoluble aerosol particles, and spherical or columnar ice crystals deriving from each aerosol type separately. Three case studies are discussed in detail to demonstrate the potential of the model to simulate real atmospheric processes and to highlight current research topics concerning aerosol and cirrus formation near the tropopause. Emphasis is placed on how the formation of cirrus clouds and the scavenging of nitric acid in cirrus depends on small-scale temperature fluctuations and the presence of efficient ice nuclei in the tropopause region, corroborating and partly extending the findings of previous studies.

16 year climatology of cirrus clouds over a tropical station in southern India using ground and space-based lidar observations

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Pandit, A. K.; Gadhavi, H. S.; Venkat Ratnam, M.; Raghunath, K.; Rao, S. V. B.; Jayaraman, A.

2015-06-01

16 year (1998-2013) climatology of cirrus clouds and their macrophysical (base height, top height and geometrical thickness) and optical properties (cloud optical thickness) observed using a ground-based lidar over Gadanki (13.5° N, 79.2° E), India, is presented. The climatology obtained from the ground-based lidar is compared with the climatology obtained from seven and half years (June 2006-December 2013) of Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) observations. A very good agreement is found between the two climatologies in spite of their opposite viewing geometries and difference in sampling frequencies. Nearly 50-55% of cirrus clouds were found to possess geometrical thickness less than 2 km. Ground-based lidar is found to detect more number of sub-visible clouds than CALIOP which has implications for global warming studies as sub-visible cirrus clouds have significant positive radiative forcing. Cirrus clouds with mid-cloud temperatures between -50 to -70 °C have a mean geometrical thickness greater than 2 km in contrast to the earlier reported value of 1.7 km. Trend analyses reveal a statistically significant increase in the altitude of sub-visible cirrus clouds which is consistent with the recent climate model simulations. Also, the fraction of sub-visible cirrus cloud is found to be increasing during the last sixteen years (1998 to 2013) which has implications to the temperature and water vapour budget in the tropical tropopause layer.

Lidar and aircraft studies of deep Cirrus systems from the 1986 FIRE IFO

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Sassen, Kenneth; Heymsfield, Andrew J.; Knight, Nancy C.

1990-01-01

Several NCAR King Air flight missions were conducted during the Wisconsin FIRE IFO experiment in support of the University of Utah polarization lidar observations of deep cirrus cloud systems at the Wausau ground site. Data collected from four cirrus systems are included in this analysis, including those of 22 and 28 October, and 1 and 2 November. Lidar data were generally obtained at 2 min intervals in the zenith direction over observation periods that ranged from approximately 4 to 10 h, bracketing the aircraft missions. The data were processed to yield height-time (HTI) displays of lidar linear depolarization ratio sigma and relative range-normalized return power P. King Air operations consisted of a combination of rapid profiling and Lagrangian spiral descents and stacked racetrack patterns in the vicinity of the field site. From the spiral descents are constructed vertical profiles of ice particle concentration N(sub i) and ice mass content IWC derived from PMS 2-D probe imagery and, when detected, FSSP cloud droplet concentration N(sub W) and liquid water content, LWC. Aircraft flight leg data are presented for the vertical velocity W and the same ice and water cloud content parameters. In addition, aerosol particle concentrations obtained with the ASAS probe are examined, and photographs of ice particles collected in-situ on oil-coated slides are presented to illustrate ice particle habit.

The 27-28 October 1986 FIRE IFO Cirrus case study: Comparison of radiative transfer theory with observations by satellite and aircraft

Science.gov (United States)

Wielicki, Bruce A.; Suttles, J. T.; Heymsfield, Andrew J.; Welch, Ronald M.; Spinhirne, James D.; Wu, Man-Li C.; Starr, David OC.; Parker, Lindsay; Arduini, Robert F.

1989-01-01

Observations of cirrus and altocumulus clouds during the First International Satellite Cloud Climatology Project Regional Experiment (FIRE) are compared to theoretical models of cloud radiative properties. Three tests are performed. First, LANDSAT radiances are used to compare the relationship between nadir reflectance ot 0.83 micron and beam emittance at 11.5 microns with that predicted for model calculations using spherical and nonspherical phase functions. Good agreement is found between observations and theory when water droplets dominate. Poor agreement is found when ice particles dominate, especially using scattering phase functions for spherical particles. Even when compared to a laboratory measured ice particle phase function, the observations show increased side scattered radiation relative to the theoretical calculations. Second, the anisotropy of conservatively scattered radiation is examined using simultaneous multiple angle views of the cirrus from LANDSAT and ER-2 aircraft radiometers. Observed anisotropy gives good agreement with theoretical calculations using the laboratory measured ice particle phase function and poor agreement with a spherical particle phase function. Third, Landsat radiances at 0.83, 1.65, and 2.21 microns are used to infer particle phase and particle size. For water droplets, good agreement is found with King Air FSSP particle probe measurements in the cloud. For ice particles, the LANDSAT radiance observations predict an effective radius of 60 microns versus aircraft observations of about 200 microns. It is suggested that this descrepancy may be explained by uncertainty in the imaginary index of ice and by inadequate measurements of small ice particles by microphysical probes.

Discriminating ability of Cirrus and RTVue optical coherence tomography in different stages of glaucoma.

Science.gov (United States)

Mittal, Deepti; Dubey, Suneeta; Gandhi, Monica; Pegu, Julie; Bhoot, Madhu; Gupta, Yadunandan Prasad

2018-05-01

The aim of this study is to determine which parameter of Cirrus and RTVue optical coherence tomography (OCT) has the highest ability to discriminate between early, moderate, and advanced glaucoma. Simultaneously, to compare the performance of the two OCT devices in terms of their ability to differentiate the three stages of glaucoma. Further, to analyze the macular parameters of both devices and compare them with the conventional retinal nerve fiber layer (RNFL) parameters. One hundred and twenty eyes (30 healthy and 90 glaucomatous [30 mild, 30 moderate, and 30 advanced glaucoma]) of 65 participants (15 healthy, 50 glaucomatous [15 mild, 15 moderate, and 20 advanced glaucoma]) underwent Cirrus and RTVue OCT scanning on a single visit. Average RNFL thickness and superior RNFL thickness of both the devices and inferior (ganglion cell complex [GCC] of RTVue device best differentiated normals from all stage glaucomatous eyes (P > 0.05). Cirrus average RNFL thickness and superior RNFL thickness performed better than other parameters (P device in different severity levels. No significant difference was observed between RNFL and macular parameters in different stages of glaucoma.

Effects of ice crystal surface roughness and air bubble inclusions on cirrus cloud radiative properties from remote sensing perspective

International Nuclear Information System (INIS)

Tang, Guanglin; Panetta, R. Lee; Yang, Ping; Kattawar, George W.; Zhai, Peng-Wang

2017-01-01

We study the combined effects of surface roughness and inhomogeneity on the optical scattering properties of ice crystals and explore the consequent implications to remote sensing of cirrus cloud properties. Specifically, surface roughness and inhomogeneity are added to the Moderate Resolution Imaging Spectroradiometer (MODIS) collection 6 (MC6) cirrus cloud particle habit model. Light scattering properties of the new habit model are simulated using a modified version of the Improved Geometric Optics Method (IGOM). Both inhomogeneity and surface roughness affect the single scattering properties significantly. In visible bands, inhomogeneity and surface roughness both tend to smooth the phase function and eliminate halos and the backscattering peak. The asymmetry parameter varies with the degree of surface roughness following a U shape - decreases and then increases - with a minimum at around 0.15, whereas it decreases monotonically with the air bubble volume fraction. Air bubble inclusions significantly increase phase matrix element -P_1_2 for scattering angles between 20°–120°, whereas surface roughness has a much weaker effect, increasing -P_1_2 slightly from 60°–120°. Radiative transfer simulations and cirrus cloud property retrievals are conducted by including both the factors. In terms of surface roughness and air bubble volume fraction, retrievals of cirrus cloud optical thickness or the asymmetry parameter using solar bands show similar patterns of variation. Polarimetric simulations using the MC6 cirrus cloud particle habit model are shown to be more consistent with observations when both surface roughness and inhomogeneity are simultaneously considered. - Highlights: • Surface roughness and air bubble inclusions affect optical properties of ice crystals significantly. • Including both factors improves simulations of ice cloud.• Cirrus cloud particle habit model of the MODIS collection 6 achieves better self-consistency and consistency with

High-latitude molecular clouds and infrared cirrus

International Nuclear Information System (INIS)

Vries, H.W. de.

1988-01-01

The high-latitude infrared cirrus detected by IRAS is identified with atomic and molecular clouds. These clouds are small (usually less than 1 sq. deg.) and show weak CO emission. On the basis of a distance of 100 pc they are characterized by a mass of a few solar masses and a radius of about 1 pc. Thermal radiation by dust as a results of heating by the diffuse interstellar radiation field is the most-plausible origin of the cirrus emission at far-infrared wavelengths. On the basis of plausible assumptions regarding the uniformity of both the gas-to-dust ratio and the heating and cooling of the dust, the flux density at 100 μm from regions with low visual extinction should be a good tracer of the gas column density. Indeed, the data show an approximately linear proportionality between N(HI), obtained from 21-cm observations, and I 100 (HI), the flux density from dust associated with HI. If the ratio of column density to flux density in high-latitude molecular clouds is equal to the corresponding relation in atomic ones, a value for the ratio of H 2 column density to CO velocity-integrated radiation temperature may be obtained. Although low-mass clouds may be large in number, the fraction of the Galactic molecular mass in the form of these clouds is probably no more than 1%

Lidar observation and model simulation of a volcanic-ash-induced cirrus cloud during the Eyjafjallajökull eruption

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C. Rolf

2012-11-01

Full Text Available Heterogeneous ice formation induced by volcanic ash from the Eyjafjallajökull volcano eruption in April 2010 is investigated based on the combination of a cirrus cloud observed with a backscatter lidar over Jülich (western Germany and model simulations along backward trajectories. The microphysical properties of the cirrus cloud could only be represented by the microphysical model under the assumption of an enhanced number of efficient ice nuclei originating from the volcanic eruption. The ice nuclei (IN concentration determined by lidar measurements directly before and after cirrus cloud occurrence implies a value of around 0.1 cm⁻³ (in comparison normal IN conditions: 0.01 cm⁻³. This leads to a cirrus cloud with rather small ice crystals having a mean radius of 12 μm and a modification of the ice particle number (0.08 cm⁻³ instead of 3 × 10⁻⁴ cm⁻³ under normal IN conditions. The effectiveness of ice nuclei was estimated by the use of the microphysical model and the backward trajectories based on ECMWF data, establishing a freezing threshold of around 105% relative humidity with respect to ice in a temperature range from −45 to −55 °C . Only with these highly efficient ice nuclei was it possible for the cirrus cloud to be formed in a slightly supersaturated environment.

Raman Lidar Measurements During the International H2O Project. 2; Instrument Comparisons and Case Studies

Science.gov (United States)

Whiteman, D. N.; Demoz, B.; DiGirolamo, P.; Corner, J.; Veselovskii, I.; Evans, K.; Wang, Z.; Sabatino, D.; Schwemmer, G.; Gentry, B.

2005-01-01

The NASA/GSFC Scanning Raman Lidar (SRL) participated in the International H2O Project (IHOP) that occurred in May and June, 2002 in the midwestern part of the U. S. The SRL system configuration and methods of data analysis were described in part I of this paper. In this second part, comparisons of SRL water vapor measurements and those of chilled mirror radiosonde and LASE airborne water vapor lidar are performed. Two case studies are presented; one for daytime and one for nighttime. The daytime case study is of a convectively driven boundary layer event and is used to characterize the SRL water vapor random error characteristics. The nighttime case study is of a thunderstorm-generated cirrus cloud case that is studied in it s meteorological context. Upper tropospheric humidification due to precipitation from the cirrus cloud is quantified as is the cirrus cloud ice water content and particle depolarization ratio. These detailed cirrus cloud measurements are being used in a cirrus cloud modeling study.

Glassy aerosols with a range of compositions nucleate ice heterogeneously at cirrus temperatures

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T. W. Wilson

2012-09-01

Full Text Available Atmospheric secondary organic aerosol (SOA is likely to exist in a semi-solid or glassy state, particularly at low temperatures and humidities. Previously, it has been shown that glassy aqueous citric acid aerosol is able to nucleate ice heterogeneously under conditions relevant to cirrus in the tropical tropopause layer (TTL. In this study we test if glassy aerosol distributions with a range of chemical compositions heterogeneously nucleate ice under cirrus conditions. Three single component aqueous solution aerosols (raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA and levoglucosan and one multi component aqueous solution aerosol (raffinose mixed with five dicarboxylic acids and ammonium sulphate were studied in both the liquid and glassy states at a large cloud simulation chamber. The investigated organic compounds have similar functionality to oxidised organic material found in atmospheric aerosol and have estimated temperature/humidity induced glass transition thresholds that fall within the range predicted for atmospheric SOA. A small fraction of aerosol particles of all compositions were found to nucleate ice heterogeneously in the deposition mode at temperatures relevant to the TTL (<200 K. Raffinose and HMMA, which form glasses at higher temperatures, nucleated ice heterogeneously at temperatures as high as 214.6 and 218.5 K respectively. We present the calculated ice active surface site density, n_s, of the aerosols tested here and also of glassy citric acid aerosol as a function of relative humidity with respect to ice (RH_i. We also propose a parameterisation which can be used to estimate heterogeneous ice nucleation by glassy aerosol for use in cirrus cloud models up to ~220 K. Finally, we show that heterogeneous nucleation by glassy aerosol may compete with ice nucleation on mineral dust particles in mid-latitudes cirrus.

Evaluation of the Anterior Segment Angle-to-Angle Scan of Cirrus High-Definition Optical Coherence Tomography and Comparison With Gonioscopy and With the Visante OCT.

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Tun, Tin A; Baskaran, Mani; Tan, Shayne S; Perera, Shamira A; Aung, Tin; Husain, Rahat

2017-01-01

To evaluate the diagnostic performance of the anterior segment angle-to-angle scan of the Cirrus high-definition optical coherence tomography (HD-OCT) in detecting eyes with closed angles. All subjects underwent dark-room gonioscopy by an ophthalmologist. A technician performed anterior segment imaging with Cirrus (n = 202) and Visante OCT (n = 85) under dark-room conditions. All eyes were categorized by two masked graders as per number of closed quadrants. Each quadrant of anterior chamber angle was categorized as a closed angle if posterior trabecular meshwork could not be seen on gonioscopy or if there was any irido-corneal contact anterior to scleral spur in Cirrus and Visante images. An eye was graded as having a closed angle if two or more quadrants were closed. Agreement and area under the curve (AUC) were performed. There were 50 (24.8%) eyes with closed angles. The agreements of closed-angle diagnosis (by eye) between Cirrus HD-OCT and gonioscopy (k = 0.59; 95% confidence interval (CI) 0.45-0.72; AC1 = 0.76) and between Cirrus and Visante OCT (k = 0.65; 95% CI 0.48-0.82, AC1 = 0.77) were moderate. The AUC for diagnosing the eye with gonioscopic closed angle by Cirrus HD-OCT was good (AUC = 0.86; sensitivity = 83.33; specificity = 77.78). The diagnostic performance of Cirrus HD-OCT in detecting the eyes with closed angles was similar to that of Visante (AUC 0.87 vs. 0.9, respectively; P = 0.51). The anterior segment angle-to-angle scans of Cirrus HD-OCT demonstrated similar diagnostic performance as Visante in detecting gonioscopic closed angles. The agreement between Cirrus and gonioscopy for detecting eyes with closed angles was moderate.

Do detailed simulations with size-resolved microphysics reproduce basic features of observed cirrus ice size distributions?

Science.gov (United States)

Fridlind, A. M.; Atlas, R.; van Diedenhoven, B.; Ackerman, A. S.; Rind, D. H.; Harrington, J. Y.; McFarquhar, G. M.; Um, J.; Jackson, R.; Lawson, P.

2017-12-01

It has recently been suggested that seeding synoptic cirrus could have desirable characteristics as a geoengineering approach, but surprisingly large uncertainties remain in the fundamental parameters that govern cirrus properties, such as mass accommodation coefficient, ice crystal physical properties, aggregation efficiency, and ice nucleation rate from typical upper tropospheric aerosol. Only one synoptic cirrus model intercomparison study has been published to date, and studies that compare the shapes of observed and simulated ice size distributions remain sparse. Here we amend a recent model intercomparison setup using observations during two 2010 SPARTICUS campaign flights. We take a quasi-Lagrangian column approach and introduce an ensemble of gravity wave scenarios derived from collocated Doppler cloud radar retrievals of vertical wind speed. We use ice crystal properties derived from in situ cloud particle images, for the first time allowing smoothly varying and internally consistent treatments of nonspherical ice capacitance, fall speed, gravitational collection, and optical properties over all particle sizes in our model. We test two new parameterizations for mass accommodation coefficient as a function of size, temperature and water vapor supersaturation, and several ice nucleation scenarios. Comparison of results with in situ ice particle size distribution data, corrected using state-of-the-art algorithms to remove shattering artifacts, indicate that poorly constrained uncertainties in the number concentration of crystals smaller than 100 µm in maximum dimension still prohibit distinguishing which parameter combinations are more realistic. When projected area is concentrated at such sizes, the only parameter combination that reproduces observed size distribution properties uses a fixed mass accommodation coefficient of 0.01, on the low end of recently reported values. No simulations reproduce the observed abundance of such small crystals when the

Parameterization of cirrus microphysical and radiative properties in larger-scale models

International Nuclear Information System (INIS)

Heymsfield, A.J.; Coen, J.L.

1994-01-01

This study exploits measurements in clouds sampled during several field programs to develop and validate parameterizations that represent the physical and radiative properties of convectively generated cirrus clouds in intermediate and large-scale models. The focus is on cirrus anvils because they occur frequently, cover large areas, and play a large role in the radiation budget. Preliminary work focuses on understanding the microphysical, radiative, and dynamical processes that occur in these clouds. A detailed microphysical package has been constructed that considers the growth of the following hydrometer types: water drops, needles, plates, dendrites, columns, bullet rosettes, aggregates, graupel, and hail. Particle growth processes include diffusional and accretional growth, aggregation, sedimentation, and melting. This package is being implemented in a simple dynamical model that tracks the evolution and dispersion of hydrometers in a stratiform anvil cloud. Given the momentum, vapor, and ice fluxes into the stratiform region and the temperature and humidity structure in the anvil's environment, this model will suggest anvil properties and structure

Retrieving cirrus microphysical properties from stellar aureoles

Science.gov (United States)

DeVore, J. G.; Kristl, J. A.; Rappaport, S. A.

2013-06-01

The aureoles around stars caused by thin cirrus limit nighttime measurement opportunities for ground-based astronomy, but can provide information on high-altitude ice crystals for climate research. In this paper we attempt to demonstrate quantitatively how this works. Aureole profiles can be followed out to ~0.2° from stars and ~0.5° from Jupiter. Interpretation of diffracted starlight is similar to that for sunlight, but emphasizes larger particles. Stellar diffraction profiles are very distinctive, typically being approximately flat out to a critical angle followed by gradually steepening power-law falloff with slope less steep than -3. Using the relationship between the phase function for diffraction and the average Fourier transform of the projected area of complex ice crystals, we show that defining particle size in terms of average projected area normal to the propagation direction of the starlight leads to a simple, analytic approximation representing large-particle diffraction that is nearly independent of crystal habit. A similar analytic approximation for the diffraction aureole allows it to be separated from the point spread function and the sky background. Multiple scattering is deconvolved using the Hankel transform leading to the diffraction phase function. Application of constrained numerical inversion to the phase function then yields a solution for the particle size distribution in the range between ~50 μm and ~400 μm. Stellar aureole measurements can provide one of the very few, as well as least expensive, methods for retrieving cirrus microphysical properties from ground-based observations.

Cirrus cloud mimic surfaces in the laboratory: organic acids, bases and NOx heterogeneous reactions

Science.gov (United States)

Sodeau, J.; Oriordan, B.

2003-04-01

CIRRUS CLOUD MIMIC SURFACES IN THE LABORATORY:ORGANIC ACIDS, BASES AND NOX HETEROGENEOUS REACTIONS. B. ORiordan, J. Sodeau Department of Chemistry and Environment Research Institute, University College Cork, Ireland j.sodeau@ucc.ie /Fax: +353-21-4902680 There are a variety of biogenic and anthropogenic sources for the simple carboxylic acids to be found in the troposphere giving rise to levels as high as 45 ppb in certain urban areas. In this regard it is of note that ants of genus Formica produce some 10Tg of formic acid each year; some ten times that produced by industry. The expected sinks are those generally associated with tropospheric chemistry: the major routes studied, to date, being wet and dry deposition. No studies have been carried out hitherto on the role of water-ice surfaces in the atmospheric chemistry of carboxylic acids and the purpose of this paper is to indicate their potential function in the heterogeneous release of atmospheric species such as HONO. The deposition of formic acid on a water-ice surface was studied using FT-RAIR spectroscopy over a range of temperatures between 100 and 165K. In all cases ionization to the formate (and oxonium) ions was observed. The results were confirmed by TPD (Temperature Programmed Desorption) measurements, which indicated that two distinct surface species adsorb to the ice. Potential reactions between the formic acid/formate ion surface and nitrogen dioxide were subsequently investigated by FT-RAIRS. Co-deposition experiments showed that N2O3 and the NO+ ion (associated with water) were formed as products. A mechanism is proposed to explain these results, which involves direct reaction between the organic acid and nitrogen dioxide. Similar experiments involving acetic acid also indicate ionization on a water-ice surface. The results are put into the context of atmospheric chemistry potentially occuring on cirrus cloud surfaces.

Variability of cirrus clouds in a convective outflow during the Hibiscus campaign

Science.gov (United States)

Fierli, F.; di Donfrancesco, G.; Cairo, F.; Marécal, V.; Zampieri, M.; Orlandi, E.; Durry, G.

2008-08-01

Light-weight microlidar and water vapour measurements were taken on-board a stratospheric balloon during the HIBISCUS 2004 campaign, held in Bauru, Brazil (49° W, 22° S). Cirrus clouds were observed throughout the flight between 12 and 15 km height with a high mesoscale variability in optical and microphysical properties. It was found that the cirrus clouds were composed of different layers characterized by marked differences in height, thickness and optical properties. Simultaneous water vapour observations show that the different layers are characterized by different values of the saturation with respect to ice. A mesoscale simulation and a trajectory analysis clearly revealed that the clouds had formed in the outflow of a large and persistent convective region and that the observed variability of the optical properties and of the cloud structure is likely linked to the different residence times of the convectively-processed air in the upper troposphere.

Cirrus Cloud Optical Thickness and Effective Diameter Retrieved by MODIS: Impacts of Single Habit Assumption, 3-D Radiative Effects, and Cloud Inhomogeneity

Science.gov (United States)

Zhou, Yongbo; Sun, Xuejin; Mielonen, Tero; Li, Haoran; Zhang, Riwei; Li, Yan; Zhang, Chuanliang

2018-01-01

For inhomogeneous cirrus clouds, cloud optical thickness (COT) and effective diameter (De) provided by the Moderate Resolution Imaging Spectrometer (MODIS) Collection 6 cloud products are associated with errors due to the single habit assumption (SHA), independent pixel assumption (IPA), photon absorption effect (PAE), and plane-parallel assumption (PPA). SHA means that every cirrus cloud is assumed to have the same shape habit of ice crystals. IPA errors are caused by three-dimensional (3D) radiative effects. PPA and PAE errors are caused by cloud inhomogeneity. We proposed a method to single out these different errors. These errors were examined using the Spherical Harmonics Discrete Ordinate Method simulations done for the MODIS 0.86 μm and 2.13 μm bands. Four midlatitude and tropical cirrus cases were studied. For the COT retrieval, the impacts of SHA and IPA were especially large for optically thick cirrus cases. SHA errors in COT varied distinctly with scattering angles. For the De retrieval, SHA decreased De under most circumstances. PAE decreased De for optically thick cirrus cases. For the COT and De retrievals, the dominant error source was SHA for overhead sun whereas for oblique sun, it could be any of SHA, IPA, and PAE, varying with cirrus cases and sun-satellite viewing geometries. On the domain average, the SHA errors in COT (De) were within -16.1%-42.6% (-38.7%-2.0%), whereas the 3-D radiative effects- and cloud inhomogeneity-induced errors in COT (De) were within -5.6%-19.6% (-2.9%-8.0%) and -2.6%-0% (-3.7%-9.8%), respectively.

Inhomogeneities in cirrus clouds and their effects on solar radiative transfer; Inhomogenitaeten in Cirren und ihre Auswirkungen auf den solaren Strahlungstransport

Energy Technology Data Exchange (ETDEWEB)

Buschmann, N. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Atmosphaerenphysik

2001-07-01

Inhomogeneities in cirrus clouds have an important impact on radiative transfer calculations in climate models. Compared to homogeneous clouds, inhomogeneities within clouds decrease reflectivity and result in an increased transmission of solar radiation through the cloud towards the surface. A quantitative investigation of this effect is still to be done. In-situ and remote sensing data of 11 cirrus clouds are used to investigate horizontal inhomogeneities. The 3-dimensional radiative transfer model GRIMALDI is used to calculate radiative flux densities and absorption for a cloudy atmosphere. Comparisons between homogeneous and heterogeneous calculations show, that the homogeneous assumption can cause relative errors up to {+-} 30% for radiative flux densities and absorption especially for tropical cirrus clouds. Mid-latitude cirrus clouds with mean optical thickness smaller than 5 and minor inhomogeneity result in relative errors smaller than {+-} 10% for radiative flux density and absorption. A correction scheme is developed to account for horizontal inhomogeneity in optically thick cirrus clouds in homogeneous radiative transfer calculations. This way, for a known horizontal distribution of optical thickness, relative errors of radiative properties can be reduced to a maximum of {+-} 10%. (orig.) [German] Inhomogenitaeten in Cirrus-Wolken spielen insbesondere bei Strahlungstransportrechnungen in Klimamodellen eine bedeutende Rolle. Im Vergleich zur homogenen Wolkenbetrachtung verringern Inhomogenitaeten die Reflektivitaet der Wolken und fuehren zu einer hoeheren Transmission solarer Strahlung durch die Wolke zum Erdboden. Eine quantitative Untersuchung dieses Effekts steht allerdings bislang aus. Flugzeugmessungen sowie Fernerkundungsdaten von insgesamt 11 Cirrus-Wolken werden auf ihre horizontale Inhomogenitaet untersucht. Das 3-dimensionale Strahlungstransportmodell GRIMALDI wird fuer die Berechnung solarer Strahlungsflussdichten und Absorption in bewoelkter

Removal of Thin Cirrus Path Radiances in the 0.4-1.0 micron Spectral Region Using the 1.375-micron Strong Water Vapor Absorption Channel

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Gao, Bo-Cai; Kaufman, Yoram J.; Han, Wei; Wiscombe, Warren J.

1998-01-01

Through analysis of spectral imaging data acquired with the Airborne Visible Infrared Imaging Spectrometer (AVIRIS) from an ER-2 aircraft at 20 km altitude during several field programs, it was found that narrow channels near the center of the strong 1.38-micron water vapor band are very sensitive in detecting thin cirrus clouds. Based on this observation from AVIRIS data, a channel centered at 1.375 microns with a width of 30 nm was selected for the Moderate Resolution Imaging Spectrometer (MODIS) for remote sensing of cirrus clouds from space. The sensitivity of the 1.375-micron MODIS channel to detect thin cirrus clouds during the day time is expected to be one to two orders of magnitude better than the current infrared emission techniques. As a result, a larger fraction of the satellite data will likely be identified as containing cirrus clouds. In order to make better studies of surface reflectance properties, thin cirrus effects must be removed from satellite images. We have developed an empirical approach for removing/correcting thin cirrus effects in the 0.4 - 1.0 micron region using channels near 1.375 microns. This algorithm will be incorporated into the present MODIS atmospheric correction algorithms for ocean color and land applications and will yield improved MODIS atmospheric aerosol, land surface, and ocean color products.

Scale dependence of cirrus horizontal heterogeneity effects on TOA measurements – Part I: MODIS brightness temperatures in the thermal infrared

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T. Fauchez

2017-07-01

Full Text Available This paper presents a study on the impact of cirrus cloud heterogeneities on MODIS simulated thermal infrared (TIR brightness temperatures (BTs at the top of the atmosphere (TOA as a function of spatial resolution from 50 m to 10 km. A realistic 3-D cirrus field is generated by the 3DCLOUD model (average optical thickness of 1.4, cloud-top and base altitudes at 10 and 12 km, respectively, consisting of aggregate column crystals of Deff = 20 µm, and 3-D thermal infrared radiative transfer (RT is simulated with the 3DMCPOL code. According to previous studies, differences between 3-D BT computed from a heterogenous pixel and 1-D RT computed from a homogeneous pixel are considered dependent at nadir on two effects: (i the optical thickness horizontal heterogeneity leading to the plane-parallel homogeneous bias (PPHB and the (ii horizontal radiative transport (HRT leading to the independent pixel approximation error (IPAE. A single but realistic cirrus case is simulated and, as expected, the PPHB mainly impacts the low-spatial-resolution results (above ∼ 250 m with averaged values of up to 5–7 K, while the IPAE mainly impacts the high-spatial-resolution results (below ∼ 250 m with average values of up to 1–2 K. A sensitivity study has been performed in order to extend these results to various cirrus optical thicknesses and heterogeneities by sampling the cirrus in several ranges of parameters. For four optical thickness classes and four optical heterogeneity classes, we have found that, for nadir observations, the spatial resolution at which the combination of PPHB and HRT effects is the smallest, falls between 100 and 250 m. These spatial resolutions thus appear to be the best choice to retrieve cirrus optical properties with the smallest cloud heterogeneity-related total bias in the thermal infrared. For off-nadir observations, the average total effect is increased and the minimum is shifted to coarser spatial

Ice Nucleation in the Tropical Tropopause Layer: Implications for Cirrus Occurrence, Cirrus Microphysical Properties, and Dehydration of Air Entering the Stratosphere

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Jensen, Eric; Kaercher, Bernd; Ueyama, Rei; Pfister, Leonhard

2017-01-01

Recent laboratory experiments have advanced our understanding of the physical properties and ice nucleating abilities of aerosol particles atlow temperatures. In particular, aerosols containing organics will transition to a glassy state at low temperatures, and these glassy aerosols are moderately effective as ice nuclei. These results have implications for ice nucleation in the cold Tropical Tropopause Layer (TTL; 13-19 km). We have developed a detailed cloud microphysical model that includes heterogeneous nucleation on a variety of aerosol types and homogeneous freezing of aqueous aerosols. This model has been incorporated into one-dimensional simulations of cirrus and water vapor driven by meteorological analysis temperature and wind fields. The model includes scavenging of ice nuclei by sedimenting ice crystals. The model is evaluated by comparing the simulated cloud properties and water vapor concentrations with aircraft and satellite measurements. In this presentation, I will discuss the relative importance of homogeneous and heterogeneous ice nucleation, the impact of ice nuclei scavenging as air slowly ascends through the TTL, and the implications for the final dehydration of air parcels crossing the tropical cold-point tropopause and entering the tropical stratosphere.

Technical note: Fu-Liou-Gu and Corti-Peter model performance evaluation for radiative retrievals from cirrus clouds

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Lolli, Simone; Campbell, James R.; Lewis, Jasper R.; Gu, Yu; Welton, Ellsworth J.

2017-06-01

We compare, for the first time, the performance of a simplified atmospheric radiative transfer algorithm package, the Corti-Peter (CP) model, versus the more complex Fu-Liou-Gu (FLG) model, for resolving top-of-the-atmosphere radiative forcing characteristics from single-layer cirrus clouds obtained from the NASA Micro-Pulse Lidar Network database in 2010 and 2011 at Singapore and in Greenbelt, Maryland, USA, in 2012. Specifically, CP simplifies calculation of both clear-sky longwave and shortwave radiation through regression analysis applied to radiative calculations, which contributes significantly to differences between the two. The results of the intercomparison show that differences in annual net top-of-the-atmosphere (TOA) cloud radiative forcing can reach 65 %. This is particularly true when land surface temperatures are warmer than 288 K, where the CP regression analysis becomes less accurate. CP proves useful for first-order estimates of TOA cirrus cloud forcing, but may not be suitable for quantitative accuracy, including the absolute sign of cirrus cloud daytime TOA forcing that can readily oscillate around zero globally.

The impact on UT/LS cirrus clouds in the CAM/CARMA model using a new interactive aerosol parameterization.

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Maloney, C.; Toon, B.; Bardeen, C.

2017-12-01

Recent studies indicate that heterogeneous nucleation may play a large role in cirrus cloud formation in the UT/LS, a region previously thought to be primarily dominated by homogeneous nucleation. As a result, it is beneficial to ensure that general circulation models properly represent heterogeneous nucleation in ice cloud simulations. Our work strives towards addressing this issue in the NSF/DOE Community Earth System Model's atmospheric model, CAM. More specifically we are addressing the role of heterogeneous nucleation in the coupled sectional microphysics cloud model, CARMA. Currently, our CAM/CARMA cirrus model only performs homogenous ice nucleation while ignoring heterogeneous nucleation. In our work, we couple the CAM/CARMA cirrus model with the Modal Aerosol Model (MAM). By combining the aerosol model with CAM/CARMA we can both account for heterogeneous nucleation, as well as directly link the sulfates used for homogeneous nucleation to computed fields instead of the current static field being utilized. Here we present our initial results and compare our findings to observations from the long running CALIPSO and MODIS satellite missions.

Cirrus cloud-temperature interactions in the tropical tropopause layer: a case study

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J. R. Taylor

2011-10-01

Full Text Available Thin cirrus clouds in the Tropical Tropopause Layer (TTL have important ramifications for radiative transfer, stratospheric humidity, and vertical transport. A horizontally extensive and vertically thin cirrus cloud in the TTL was detected by the Cloud Aerosol LIDAR and Infrared Pathfinder Satellite Observations (CALIPSO on 27–29 January 2009 in the Tropical Eastern Pacific region, distant from any regions of deep convection. These observations indicate that the cloud is close to 3000 km in length along the CALIPSO orbit track. Measurements over this three day period indicate that the cloud event extended over a region from approximately 15° S to 10° N and 90° W to 150° W and may be one of the most extensive cirrus events ever observed. Coincident temperature observations from the Constellation of Observing Satellites for Meteorology, Ionosphere, and Climate (COSMIC suggest that the cloud formed in-situ as a result of a cold anomaly arising from a midlatitude intrusion. The event appears to last for up to 2 days and the temperature observations do not show any indication of the expected infrared heating. It is hypothesized that the cloud could be maintained by either nucleation of numerous small ice crystals that don't sediment or by multiple localized ice nucleation events driven by temperature variability at scales smaller than the overall cloud field, producing small ice-crystal sizes which have sufficiently long residence times (≈53 h to maintain the cloud. It is possible that the residence times are augmented by vertical motion which could also act to offset the expected infrared heating. Further observations of similar events will be required in order to conclusively explain this curious cloud.

Subfoveal choroidal thickness measured by Cirrus HD optical coherence tomography in myopia

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Li-Li Chen

2014-09-01

Full Text Available ATM: To measure the subfoveal choroidal thickness(SFCTin myopia using Cirrus HD optical coherence tomography(OCT, and to explore the relationship between the SFCT, axial length and myopic refractive spherical equivalent.METHODS: One-hundred thirty-three eyes of 70 healthy volunteers were recruited, and were divided into emmetropia group, low-degree myopia, middle-degree myopia and high-degree myopia group. SFCT were measured by Cirrus HD OCT, and the relationship between the SFCT, axial length and myopic refractive spherical equivalent were evaluated.RESULTS: 1Average SFCT was(275.91±55.74μm in normals, that in emmetropia group, low-degree myopia, middle-degree myopia and high-degree myopia group were(290.03±34.82μm,(287.64±51.51μm,(274.95±56.83μm,(248.37±67.98μm; 2the SFCT of high-degree myopia group was significant thinner than that of emmetropia group(PPPCONCLUSION: the SFCT is inversely correlated with increasing axial length and myopic refractive error.

Reducing Striping and Near Field Response Influence in the MODIS 1.38um Cirrus Detection Band.

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Ackerman, S. A.; Moeller, C. C.; Frey, R. A.; Gumley, L. E.; Menzel, W. P.

2002-05-01

Since first light in February 2000, the MODIS L1B data from Terra has exhibited detector striping in the cirrus detection band at 1.38 um (B26). This band's unique characteristic is that it is potentially able to discriminate very thin cirrus (optical depth of 0.1) because water vapor absorption effectively attenuates the upwelling signal from the earth's surface, leaving a flat dark background underneath the thin cirrus. The striping has diminished the power of this band for detecting thin cirrus in the MODIS Cloud Mask (MOD35) over the global environment by imparting a structure on the background. The striping amplitude (valley to peak) is 10 - 15% of the MODIS Ltyp radiance in B26 over land backgrounds, thus exceeding the 5% radiance prelaunch accuracy specification for the band. Also unexpected has been the presence of earth surface reflectance in B26. Forward model calculations indicate that the two-way transmittance of B26 in-band (1% to 1% response) should be water (TPW) exceeds about 12 mm. However, MODIS B26 imagery has routinely shown land surface reflectance, such as Florida, even in very moist (TPW > 30 mm) tropical air masses. MODIS prelaunch test data suggests that a near field response (NFR) at about 1.3 um in the B26 filter may be contributing to this behavior. A destriping and out-of-band correction algorithm has been under development at the University of Wisconsin to address the these issues. The simple linear algorithm is based on tuning detector dependent influence coefficients for B26 as a function of B5 (1.24 um) radiance so that the corrected B26 radiance is near zero for all B26 detectors in moist atmospheric conditions. B5 was chosen as a surrogate to characterize the NFR leak in the B26 filter because of its close spectral proximity to the NFR leak. Real MODIS L1B data is being used to estimate the influence coefficients. The paper will describe the B5 based destriping and NFR correction algorithm and influence coefficient development. It

“Using Statistical Comparisons between SPartICus Cirrus Microphysical Measurements, Detailed Cloud Models, and GCM Cloud Parameterizations to Understand Physical Processes Controlling Cirrus Properties and to Improve the Cloud Parameterizations”

Energy Technology Data Exchange (ETDEWEB)

Woods, Sarah [SPEC Inc., Boulder, CO (United States)

2015-12-01

The dual objectives of this project were improving our basic understanding of processes that control cirrus microphysical properties and improvement of the representation of these processes in the parameterizations. A major effort in the proposed research was to integrate, calibrate, and better understand the uncertainties in all of these measurements.

An Accounting International Experience Course

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Johnson, Leigh Redd; Rudolph, Holly R.; Seay, Robert A.

2010-01-01

Accounting students need practical opportunities to personally experience other cultures and international business practices if they are to effectively compete in today's global marketplace. In order to address this need, the Department of Accounting at Murray State University offers an international experience course which includes a short-term…

Evaluation of cloud-resolving model simulations of midlatitude cirrus with ARM and A-train observations

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Muhlbauer, A.; Ackerman, T. P.; Lawson, R. P.; Xie, S.; Zhang, Y.

2015-07-01

Cirrus clouds are ubiquitous in the upper troposphere and still constitute one of the largest uncertainties in climate predictions. This paper evaluates cloud-resolving model (CRM) and cloud system-resolving model (CSRM) simulations of a midlatitude cirrus case with comprehensive observations collected under the auspices of the Atmospheric Radiation Measurements (ARM) program and with spaceborne observations from the National Aeronautics and Space Administration A-train satellites. The CRM simulations are driven with periodic boundary conditions and ARM forcing data, whereas the CSRM simulations are driven by the ERA-Interim product. Vertical profiles of temperature, relative humidity, and wind speeds are reasonably well simulated by the CSRM and CRM, but there are remaining biases in the temperature, wind speeds, and relative humidity, which can be mitigated through nudging the model simulations toward the observed radiosonde profiles. Simulated vertical velocities are underestimated in all simulations except in the CRM simulations with grid spacings of 500 m or finer, which suggests that turbulent vertical air motions in cirrus clouds need to be parameterized in general circulation models and in CSRM simulations with horizontal grid spacings on the order of 1 km. The simulated ice water content and ice number concentrations agree with the observations in the CSRM but are underestimated in the CRM simulations. The underestimation of ice number concentrations is consistent with the overestimation of radar reflectivity in the CRM simulations and suggests that the model produces too many large ice particles especially toward the cloud base. Simulated cloud profiles are rather insensitive to perturbations in the initial conditions or the dimensionality of the model domain, but the treatment of the forcing data has a considerable effect on the outcome of the model simulations. Despite considerable progress in observations and microphysical parameterizations, simulating

Comparing airborne and satellite retrievals of cloud optical thickness and particle effective radius using a spectral radiance ratio technique: two case studies for cirrus and deep convective clouds

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Krisna, Trismono C.; Wendisch, Manfred; Ehrlich, André; Jäkel, Evelyn; Werner, Frank; Weigel, Ralf; Borrmann, Stephan; Mahnke, Christoph; Pöschl, Ulrich; Andreae, Meinrat O.; Voigt, Christiane; Machado, Luiz A. T.

2018-04-01

Solar radiation reflected by cirrus and deep convective clouds (DCCs) was measured by the Spectral Modular Airborne Radiation Measurement System (SMART) installed on the German High Altitude and Long Range Research Aircraft (HALO) during the Mid-Latitude Cirrus (ML-CIRRUS) and the Aerosol, Cloud, Precipitation, and Radiation Interaction and Dynamic of Convective Clouds System - Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modelling and to the Global Precipitation Measurement (ACRIDICON-CHUVA) campaigns. On particular flights, HALO performed measurements closely collocated with overpasses of the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite. A cirrus cloud located above liquid water clouds and a DCC topped by an anvil cirrus are analyzed in this paper. Based on the nadir spectral upward radiance measured above the two clouds, the optical thickness τ and particle effective radius reff of the cirrus and DCC are retrieved using a radiance ratio technique, which considers the cloud thermodynamic phase, the vertical profile of cloud microphysical properties, the presence of multilayer clouds, and the heterogeneity of the surface albedo. For the cirrus case, the comparison of τ and reff retrieved on the basis of SMART and MODIS measurements yields a normalized mean absolute deviation of up to 1.2 % for τ and 2.1 % for reff. For the DCC case, deviations of up to 3.6 % for τ and 6.2 % for reff are obtained. The larger deviations in the DCC case are mainly attributed to the fast cloud evolution and three-dimensional (3-D) radiative effects. Measurements of spectral upward radiance at near-infrared wavelengths are employed to investigate the vertical profile of reff in the cirrus. The retrieved values of reff are compared with corresponding in situ measurements using a vertical weighting method. Compared to the MODIS observations, measurements of SMART provide more information on the

On the origin of subvisible cirrus clouds in the tropical upper troposphere

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M. Reverdy

2012-12-01

Full Text Available Spaceborne lidar observations have recently revealed a previously undetected significant population of Subvisible Cirrus (SVC. We show them to be colder than −74 °, with an optical depth below 0.0015 on average. The formation and persistence over time of this new cloud population could be related to several atmospheric phenomena. In this paper, we investigate if these clouds follow the same formation mechanisms as the general tropical cirrus population (including convection and in-situ ice nucleation, or if specific nucleation sites and trace species play a role in their formation. The importance of three scenarios in the formation of the global SVC population is investigated through different approaches that include comparisons with data imaging from several spaceborne instruments and back-trajectories that document the history and behavior of air masses leading to the point in time and space where subvisible cirrus were detected. In order to simplify the study of their formation, we singled out SVC with coherent temperature histories (mean variance lower than 4 K according to back-trajectories along 5, 10 or 15 days (respectively 58, 25 and 11% of SVC. Our results suggest that external processes, including local increases in liquid and hygroscopic aerosol concentration (either through biomass burning or volcanic injection forming sulfate-based aerosols in the troposphere or the stratosphere have very limited short-term or mid-term impact on the SVC population. On the other hand, we find that ~20% of air masses leading to SVC formation interacted with convective activity 5 days before they led to cloud formation and detection, a number that climbs to 60% over 15 days. SVC formation appears especially linked to convection over Africa and Central America, more so during JJA than DJF. These results support the view that the SVC population observed by CALIOP is an extension of the general upper tropospheric ice clouds population with its extreme

Assessment of cirrus cloud and aerosol radiative effect in South-East Asia by ground-based NASA MPLNET lidar network data and CALIPSO satellite measurements

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Lolli, Simone; Campbell, James R.; Lewis, Jasper R.; Welton, Ellsworth J.; Di Girolamo, Paolo; Fatkhuroyan, Fatkhuroyan; Gu, Yu; Marquis, Jared W.

2017-10-01

Aerosol, together with cirrus clouds, play a fundamental role in the earth-atmosphere system radiation budget, especially at tropical latitudes, where the Earth surface coverage by cirrus cloud can easily reach 70%. In this study we evaluate the combined aerosol and cirrus cloud net radiative effects in a wild and barren region like South East Asia. This part of the world is extremely vulnerable to climate change and it is source of important anthropogenic and natural aerosol emissions. The analysis has been carried out by computing cirrus cloud and aerosol net radiative effects through the Fu-Liou-Gu atmospheric radiative transfer model, adequately adapted to input lidar measurements, at surface and top-of-the atmosphere. The aerosol radiative effects were computed respectively using the retrieved lidar extinction from Cloud-Aerosol Lidar with Orthogonal Polarization in 2011 and 2012 and the lidar on-board of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations for the South East Asia Region (27N-12S, 77E-132E) with 5° x 5° spatial resolution. To assess the cirrus cloud radiative effect, we used the ground-based Micro Pulse Lidar Network measurements at Singapore permanent observational site. Results put in evidence that strong aerosol emission areas are related on average to a net surface cooling. On the contrary, cirrus cloud radiative effect shows a net daytime positive warming of the system earth-atmosphere. This effect is weak over the ocean where the albedo is lower and never counter-balances the net cooling produced by aerosols. The net cooling is stronger in 2011, with an associated reduction in precipitations by the four of the five rain-gauges stations deployed in three regions as Sumatra, Kalimantan and Java with respect to 2012. We can speculate that aerosol emissions may be associated with lower rainfall, however some very important phenomena as El Nino Southern Oscillation , Madden-Julian Oscillation, Monsoon and Indian Dipole are not

Investigating Freezing Point Depression and Cirrus Cloud Nucleation Mechanisms Using a Differential Scanning Calorimeter

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Bodzewski, Kentaro Y.; Caylor, Ryan L.; Comstock, Ashley M.; Hadley, Austin T.; Imholt, Felisha M.; Kirwan, Kory D.; Oyama, Kira S.; Wise, Matthew E.

2016-01-01

A differential scanning calorimeter was used to study homogeneous nucleation of ice from micron-sized aqueous ammonium sulfate aerosol particles. It is important to understand the conditions at which these particles nucleate ice because of their connection to cirrus cloud formation. Additionally, the concept of freezing point depression, a topic…

Interference phenomena at backscattering by ice crystals of cirrus clouds.

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Borovoi, Anatoli; Kustova, Natalia; Konoshonkin, Alexander

2015-09-21

It is shown that light backscattering by hexagonal ice crystals of cirrus clouds is formed within the physical-optics approximation by both diffraction and interference phenomena. Diffraction determines the angular width of the backscattering peak and interference produces the interference rings inside the peak. By use of a simple model for distortion of the pristine hexagonal shape, we show that the shape distortion leads to both oscillations of the scattering (Mueller) matrix within the backscattering peak and to a strong increase of the depolarization, color, and lidar ratios needed for interpretation of lidar signals.

Retrieval of subvisual cirrus cloud optical thickness from limb-scatter measurements

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J. T. Wiensz

2013-01-01

Full Text Available We present a technique for estimating the optical thickness of subvisual cirrus clouds detected by OSIRIS (Optical Spectrograph and Infrared Imaging System, a limb-viewing satellite instrument that measures scattered radiances from the UV to the near-IR. The measurement set is composed of a ratio of limb radiance profiles at two wavelengths that indicates the presence of cloud-scattering regions. Cross-sections and phase functions from an in situ database are used to simulate scattering by cloud-particles. With appropriate configurations discussed in this paper, the SASKTRAN successive-orders of scatter radiative transfer model is able to simulate accurately the in-cloud radiances from OSIRIS. Configured in this way, the model is used with a multiplicative algebraic reconstruction technique (MART to retrieve the cloud extinction profile for an assumed effective cloud particle size. The sensitivity of these retrievals to key auxiliary model parameters is shown, and it is shown that the retrieved extinction profile, for an assumed effective cloud particle size, models well the measured in-cloud radiances from OSIRIS. The greatest sensitivity of the retrieved optical thickness is to the effective cloud particle size. Since OSIRIS has an 11-yr record of subvisual cirrus cloud detections, the work described in this manuscript provides a very useful method for providing a long-term global record of the properties of these clouds.

Characterization of optical and micro-physical properties of cirrus clouds using a wideband thermal infrared spectrometer

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Palchetti, Luca; Di Natale, Gianluca; Bianchini, Giovanni

2014-05-01

High-altitude ice clouds such as cirrus clouds play a key role in the Earth's radiation budget since they cover permanently about 20-30% of the surface of the planet, reaching even to 60-70% in the tropics. The modulation of the incoming solar radiation and the outgoing Earth's thermal emission due to cirrus can contribute to heat or to cool the atmosphere, according to their optical properties, which must be characterised with great accuracy and over the whole spectral range involved in the scattering and emission processes. Here we present the infrared measurements over the wide spectral range from 9 to 50 micron performed by the Fourier transform spectrometer REFIR-PAD (Radiation Explorer in Far InfraRed - Prototype for Application and Development) during many field campaigns that have taken place since 2007 from different high-altitude ground-based stations: Testa Grigia Station, Cervinia-Italy, (3480 m asl), Cerro Toco, Atacama-Chile, (5380 m asl), Concordia Base, Dome C-Antarctica (3230 m asl). These measurements show for the first time the spectral effect of cirrus clouds in the long-wave part of the emission spectrum above 15 micron of wavelength. To characterise these measurements over the wide spectral range as a function of the optical properties of ice particles, a model of the radiative transfer, that integrates the well known numerical code LBLRTM, which simulates the radiative transfer in the atmosphere, with a specific code which simulates the propagation of the radiation through the cloud, was developed. The optical properties of clouds have been modelled using the δ-scaled Eddington approximation for a single layer and the Ping Yang's database for the single-scattering properties of ice crystals. The preliminary results of the fit procedure used for the determination of the micro-physical parameters of ice crystals, such as the effective diameter, ice water path, effective temperature and optical thickness will be shown in the presentation. The

Towards a Model Climatology of Relative Humidity in the Upper Troposphere for Estimation of Contrail and Contrail-Induced Cirrus

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Selkirk, Henry B.; Manyin, M.; Ott, L.; Oman, L.; Benson, C.; Pawson, S.; Douglass, A. R.; Stolarski, R. S.

2011-01-01

The formation of contrails and contrail cirrus is very sensitive to the relative humidity of the upper troposphere. To reduce uncertainty in an estimate of the radiative impact of aviation-induced cirrus, a model must therefore be able to reproduce the observed background moisture fields with reasonable and quantifiable fidelity. Here we present an upper tropospheric moisture climatology from a 26-year ensemble of simulations using the GEOS CCM. We compare this free-running model's moisture fields to those obtained from the MLS and AIRS satellite instruments, our most comprehensive observational databases for upper tropospheric water vapor. Published comparisons have shown a substantial wet bias in GEOS-5 assimilated fields with respect to MLS water vapor and ice water content. This tendency is clear as well in the GEOS CCM simulations. The GEOS-5 moist physics in the GEOS CCM uses a saturation adjustment that prevents supersaturation, which is unrealistic when compared to in situ moisture observations from MOZAIC aircraft and balloon sondes as we will show. Further, the large-scale satellite datasets also consistently underestimate super-saturation when compared to the in-situ observations. We place these results in the context of estimates of contrail and contrail cirrus frequency.

75 FR 20518 - Special Conditions: Cirrus Design Corporation Model SF50 Airplane; Full Authority Digital Engine...

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2010-04-20

... issuance. Comments Invited Interested persons are invited to submit such written data, views, or arguments... On September 9, 2008, Cirrus Design Corporation applied for a type certificate for their new model... the digital engine control must provide an equivalent reliability to mechanical engine controls. Type...

Understanding Cirrus Ice Crystal Number Variability for Different Heterogeneous Ice Nucleation Spectra

Science.gov (United States)

Sullivan, Sylvia C.; Betancourt, Ricardo Morales; Barahona, Donifan; Nenes, Athanasios

2016-01-01

Along with minimizing parameter uncertainty, understanding the cause of temporal and spatial variability of the nucleated ice crystal number, Ni, is key to improving the representation of cirrus clouds in climate models. To this end, sensitivities of Ni to input variables like aerosol number and diameter provide valuable information about nucleation regime and efficiency for a given model formulation. Here we use the adjoint model of the adjoint of a cirrus formation parameterization (Barahona and Nenes, 2009b) to understand Ni variability for various ice-nucleating particle (INP) spectra. Inputs are generated with the Community Atmosphere Model version 5, and simulations are done with a theoretically derived spectrum, an empirical lab-based spectrum and two field-based empirical spectra that differ in the nucleation threshold for black carbon particles and in the active site density for dust. The magnitude and sign of Ni sensitivity to insoluble aerosol number can be directly linked to nucleation regime and efficiency of various INP. The lab-based spectrum calculates much higher INP efficiencies than field-based ones, which reveals a disparity in aerosol surface properties. Ni sensitivity to temperature tends to be low, due to the compensating effects of temperature on INP spectrum parameters; this low temperature sensitivity regime has been experimentally reported before but never deconstructed as done here.

Evaluation of cloud resolving model simulations of midlatitude cirrus with ARM and A-Train observations

Science.gov (United States)

Muehlbauer, A. D.; Ackerman, T. P.; Lawson, P.; Xie, S.; Zhang, Y.

2015-12-01

This paper evaluates cloud resolving model (CRM) and cloud system-resolving model (CSRM) simulations of a midlatitude cirrus case with comprehensive observations collected under the auspices of the Atmospheric Radiation Measurements (ARM) program and with spaceborne observations from the National Aeronautics and Space Administration (NASA) A-train satellites. Vertical profiles of temperature, relative humidity and wind speeds are reasonably well simulated by the CSRM and CRM but there are remaining biases in the temperature, wind speeds and relative humidity, which can be mitigated through nudging the model simulations toward the observed radiosonde profiles. Simulated vertical velocities are underestimated in all simulations except in the CRM simulations with grid spacings of 500m or finer, which suggests that turbulent vertical air motions in cirrus clouds need to be parameterized in GCMs and in CSRM simulations with horizontal grid spacings on the order of 1km. The simulated ice water content and ice number concentrations agree with the observations in the CSRM but are underestimated in the CRM simulations. The underestimation of ice number concentrations is consistent with the overestimation of radar reflectivity in the CRM simulations and suggests that the model produces too many large ice particles especially toward cloud base. Simulated cloud profiles are rather insensitive to perturbations in the initial conditions or the dimensionality of the model domain but the treatment of the forcing data has a considerable effect on the outcome of the model simulations. Despite considerable progress in observations and microphysical parameterizations, simulating the microphysical, macrophysical and radiative properties of cirrus remains challenging. Comparing model simulations with observations from multiple instruments and observational platforms is important for revealing model deficiencies and for providing rigorous benchmarks. However, there still is considerable

Modeling single-scattering properties of small cirrus particles by use of a size-shape distribution of ice spheroids and cylinders

International Nuclear Information System (INIS)

Liu Li; Mishchenko, Michael I.; Cairns, Brian; Carlson, Barbara E.; Travis, Larry D.

2006-01-01

In this study, we model single-scattering properties of small cirrus crystals using mixtures of polydisperse, randomly oriented spheroids and cylinders with varying aspect ratios and with a refractive index representative of water ice at a wavelength of 1.88 μm. The Stokes scattering matrix elements averaged over wide shape distributions of spheroids and cylinders are compared with those computed for polydisperse surface-equivalent spheres. The shape-averaged phase function for a mixture of oblate and prolate spheroids is smooth, featureless, and nearly flat at side-scattering angles and closely resembles those typically measured for cirrus. Compared with the ensemble-averaged phase function for spheroids, that for a shape distribution of cylinders shows a relatively deeper minimum at side-scattering angles. This may indicate that light scattering from realistic cirrus crystals can be better represented by a shape mixture of ice spheroids. Interestingly, the single-scattering properties of shape-averaged oblate and prolate cylinders are very similar to those of compact cylinders with a diameter-to-length ratio of unity. The differences in the optical cross sections, single-scattering albedo, and asymmetry parameter between the spherical and the nonspherical particles studied appear to be relatively small. This may suggest that for a given optical thickness, the influence of particle shape on the radiative forcing caused by a cloud composed of small ice crystals can be negligible

Strategies for cloud-top phase determination: differentiation between thin cirrus clouds and snow in manual (ground truth) analyses

Science.gov (United States)

Hutchison, Keith D.; Etherton, Brian J.; Topping, Phillip C.

1996-12-01

Quantitative assessments on the performance of automated cloud analysis algorithms require the creation of highly accurate, manual cloud, no cloud (CNC) images from multispectral meteorological satellite data. In general, the methodology to create ground truth analyses for the evaluation of cloud detection algorithms is relatively straightforward. However, when focus shifts toward quantifying the performance of automated cloud classification algorithms, the task of creating ground truth images becomes much more complicated since these CNC analyses must differentiate between water and ice cloud tops while ensuring that inaccuracies in automated cloud detection are not propagated into the results of the cloud classification algorithm. The process of creating these ground truth CNC analyses may become particularly difficult when little or no spectral signature is evident between a cloud and its background, as appears to be the case when thin cirrus is present over snow-covered surfaces. In this paper, procedures are described that enhance the researcher's ability to manually interpret and differentiate between thin cirrus clouds and snow-covered surfaces in daytime AVHRR imagery. The methodology uses data in up to six AVHRR spectral bands, including an additional band derived from the daytime 3.7 micron channel, which has proven invaluable for the manual discrimination between thin cirrus clouds and snow. It is concluded that while the 1.6 micron channel remains essential to differentiate between thin ice clouds and snow. However, this capability that may be lost if the 3.7 micron data switches to a nighttime-only transmission with the launch of future NOAA satellites.

International experience of microcredit

OpenAIRE

Nazarenko, M.; Nazarenko, O.

2014-01-01

The authors analyze international experience of microcredit development and made appropriate conclusions about the advantages and disadvantages of microcredit organization. Microcredit organizations are self-sufficient and stable institutions which are regulated by bank and state legislation.

International practice experiences in pharmacy education.

Science.gov (United States)

Cisneros, Robert M; Jawaid, Sarah Parnapy; Kendall, Debra A; McPherson, Charles E; Mu, Keli; Weston, Grady Scott; Roberts, Kenneth B

2013-11-12

To identify reasons for inclusion of international practice experiences in pharmacy curricula and to understand the related structure, benefits, and challenges related to the programs. A convenience sample of 20 colleges and schools of pharmacy in the United States with international pharmacy education programs was used. Telephone interviews were conducted by 2 study investigators. University values and strategic planning were among key driving forces in the development of programs. Global awareness and cultural competency requirements added impetus to program development. Participants' advice for creating an international practice experience program included an emphasis on the value of working with university health professions programs and established travel programs. Despite challenges, colleges and schools of pharmacy value the importance of international pharmacy education for pharmacy students as it increases global awareness of health needs and cultural competencies.

Retrieving microphysics of cirrus clouds from data measured with raman lidar ramses and a tilted ceilometer

Science.gov (United States)

Borovoi, Anatoli; Reichardt, Jens; Görsdorf, Ulrich; Wolf, Veronika; Konoshonkin, Alexander; Shishko, Victor; Kustova, Natalia

2018-04-01

To develop a microphysical model of cirrus clouds, data obtained by Raman lidar RAMSES and a tilted ceilometer are studied synergistically. The measurements are interpreted by use of a data archive containing the backscattering matrixes as well as the depolarization, color and lidar ratios of ice crystals of different shapes, sizes and spatial orientations calculated within the physical-optics approximation.

A modelling study of the impact of cirrus clouds on the moisture budget of the upper troposphere

Directory of Open Access Journals (Sweden)

S. Fueglistaler

2006-01-01

Full Text Available We present a modelling study of the effect of cirrus clouds on the moisture budget of the layer wherein the cloud formed. Our framework simplifies many aspects of cloud microphysics and collapses the problem of sedimentation onto a 0-dimensional box model, but retains essential feedbacks between saturation mixing ratio, particle growth, and water removal through particle sedimentation. The water budget is described by two coupled first-order differential equations for dimensionless particle number density and saturation point temperature, where the parameters defining the system (layer depth, reference temperature, amplitude and time scale of temperature perturbation and inital particle number density, which may or may not be a function of reference temperature and cooling rate are encapsulated in a single coefficient. This allows us to scale the results to a broad range of atmospheric conditions, and to test sensitivities. Results of the moisture budget calculations are presented for a range of atmospheric conditions (T: 238–205 K; p: 325–180 hPa and a range of time scales τT of the temperature perturbation that induces the cloud formation. The cirrus clouds are found to efficiently remove water for τT longer than a few hours, with longer perturbations (τT≳10 h required at lower temperatures (T≲210 K. Conversely, we find that temperature perturbations of duration order 1 h and less (a typical timescale for e.g., gravity waves do not efficiently dehydrate over most of the upper troposphere. A consequence is that (for particle densities typical of current cirrus clouds the assumption of complete dehydration to the saturation mixing ratio may yield valid predictions for upper tropospheric moisture distributions if it is based on the large scale temperature field, but this assumption is not necessarily valid if it is based on smaller scale temperature fields.

Microphysical and optical properties of contrails and cirrus

Energy Technology Data Exchange (ETDEWEB)

Gayet, J F; Febvre, G [Universite Blaise Pascal, Clermont-Ferand (France). Lab. de Meteorologie Physique; Brogniez, G [Universite des Sciences et Techniques de Lille, (France). Lab. d` Optique Atmospherique; Wendling, P [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere; Larsen, H [National Inst. for Water and Atmospheric Research, Wellington (New Zealand)

1998-12-31

Aircraft contrails have significantly different properties to natural cirrus clouds. Their local and global climate impact cannot be assessed without consideration of these differences. Microphysical data were obtained from the Merlin aircraft equipped with a PMS FSSP-100 for particle spectrum measurements over the 3 {mu}m to 45 {mu}m diameter range; a PMS 2D-C for particle size spectrum and particle shape over the size range from 25 {mu}m to 800 {mu}m and a Johnson-Williams cloud liquid-water probe. Radiative measurements were obtained from a Do228 aircraft which carried the upward looking ALEX-F Lidar operating at a wavelength of 1.06 {mu}m and a Barnes PRT-5 radiometer aligned parallel to the lidar and with a 9 to 11 {mu}m spectral range. The limitation in accuracy of cloud microphysical sensor used in contrail studies are also discussed with subsequent errors on description of cloud radiative properties. (R.P.) 9 refs.

Microphysical and optical properties of contrails and cirrus

Energy Technology Data Exchange (ETDEWEB)

Gayet, J.F.; Febvre, G. [Universite Blaise Pascal, Clermont-Ferand (France). Lab. de Meteorologie Physique; Brogniez, G. [Universite des Sciences et Techniques de Lille, (France). Lab. d`Optique Atmospherique; Wendling, P. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere; Larsen, H. [National Inst. for Water and Atmospheric Research, Wellington (New Zealand)

1997-12-31

Aircraft contrails have significantly different properties to natural cirrus clouds. Their local and global climate impact cannot be assessed without consideration of these differences. Microphysical data were obtained from the Merlin aircraft equipped with a PMS FSSP-100 for particle spectrum measurements over the 3 {mu}m to 45 {mu}m diameter range; a PMS 2D-C for particle size spectrum and particle shape over the size range from 25 {mu}m to 800 {mu}m and a Johnson-Williams cloud liquid-water probe. Radiative measurements were obtained from a Do228 aircraft which carried the upward looking ALEX-F Lidar operating at a wavelength of 1.06 {mu}m and a Barnes PRT-5 radiometer aligned parallel to the lidar and with a 9 to 11 {mu}m spectral range. The limitation in accuracy of cloud microphysical sensor used in contrail studies are also discussed with subsequent errors on description of cloud radiative properties. (R.P.) 9 refs.

Real-Time Very High-Resolution Regional 4D Assimilation in Supporting CRYSTAL-FACE Experiment

Science.gov (United States)

Wang, Donghai; Minnis, Patrick

2004-01-01

To better understand tropical cirrus cloud physical properties and formation processes with a view toward the successful modeling of the Earth's climate, the CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment) field experiment took place over southern Florida from 1 July to 29 July 2002. During the entire field campaign, a very high-resolution numerical weather prediction (NWP) and assimilation system was performed in support of the mission with supercomputing resources provided by NASA Center for Computational Sciences (NCCS). By using NOAA NCEP Eta forecast for boundary conditions and as a first guess for initial conditions assimilated with all available observations, two nested 15/3 km grids are employed over the CRYSTAL-FACE experiment area. The 15-km grid covers the southeast US domain, and is run two times daily for a 36-hour forecast starting at 0000 UTC and 1200 UTC. The nested 3-km grid covering only southern Florida is used for 9-hour and 18-hour forecasts starting at 1500 and 0600 UTC, respectively. The forecasting system provided more accurate and higher spatial and temporal resolution forecasts of 4-D atmospheric fields over the experiment area than available from standard weather forecast models. These forecasts were essential for flight planning during both the afternoon prior to a flight day and the morning of a flight day. The forecasts were used to help decide takeoff times and the most optimal flight areas for accomplishing the mission objectives. See more detailed products on the web site http://asd-www.larc.nasa.gov/mode/crystal. The model/assimilation output gridded data are archived on the NASA Center for Computational Sciences (NCCS) UniTree system in the HDF format at 30-min intervals for real-time forecasts or 5-min intervals for the post-mission case studies. Particularly, the data set includes the 3-D cloud fields (cloud liquid water, rain water, cloud ice, snow and graupe/hail).

Polarized internal targets for electronuclear experiments

International Nuclear Information System (INIS)

van den Brand, J.F.J.

1993-01-01

Polarized internal gas targets represent a unique opportunity for the measurement of spin observables in electro-nuclear physics. Two measurements will be discussed. First, spin observables have been measured in elastic and quasi-free scattering of 45, 200, 300, and 415 MeV polarized protons from a polarized 3 He internal gas target at the Indiana University Cyclotron Facility Cooler Ring. The data obtained constitute the first measurement of spin correlation parameters using a storage ring with polarized beam and polarized internal gas target. Second, a quasi-free (e,e'p) experiment using tensor polarized deuterium will be discussed. Here, the goal is the measurement of the S- and D-state parts of the proton spectral function by scattering 700 MeV electrons from an atomic beam source. Large acceptance detectors have been used in both experiments. The internal-target technique has broad applicability in nuclear and particle physics

Possible influence of anthropogenic aerosols on cirrus clouds and anthropogenic forcing

Directory of Open Access Journals (Sweden)

J. E. Penner

2009-02-01

Full Text Available Cirrus clouds have a net warming effect on the atmosphere and cover about 30% of the Earth's area. Aerosol particles initiate ice formation in the upper troposphere through modes of action that include homogeneous freezing of solution droplets, heterogeneous nucleation on solid particles immersed in a solution, and deposition nucleation of vapor onto solid particles. Here, we examine the possible change in ice number concentration from anthropogenic soot originating from surface sources of fossil fuel and biomass burning, from anthropogenic sulfate aerosols, and from aircraft that deposit their aerosols directly in the upper troposphere. We use a version of the aerosol model that predicts sulfate number and mass concentrations in 3-modes and includes the formation of sulfate aerosol through homogeneous binary nucleation as well as a version that only predicts sulfate mass. The 3-mode version best represents the Aitken aerosol nuclei number concentrations in the upper troposphere which dominated ice crystal residues in the upper troposphere. Fossil fuel and biomass burning soot aerosols with this version exert a radiative forcing of −0.3 to −0.4 Wm⁻² while anthropogenic sulfate aerosols and aircraft aerosols exert a forcing of −0.01 to 0.04 Wm⁻² and −0.16 to −0.12 Wm⁻², respectively, where the range represents the forcing from two parameterizations for ice nucleation. The sign of the forcing in the mass-only version of the model depends on which ice nucleation parameterization is used and can be either positive or negative. The magnitude of the forcing in cirrus clouds can be comparable to the forcing exerted by anthropogenic aerosols on warm clouds, but this forcing has not been included in past assessments of the total anthropogenic radiative forcing of climate.

Importance of aggregation and small ice crystals in cirrus clouds, based on observations and an ice particle growth model

Science.gov (United States)

Mitchell, David L.; Chai, Steven K.; Dong, Yayi; Arnott, W. Patrick; Hallett, John

1993-01-01

The 1 November 1986 FIRE I case study was used to test an ice particle growth model which predicts bimodal size spectra in cirrus clouds. The model was developed from an analytically based model which predicts the height evolution of monomodal ice particle size spectra from the measured ice water content (IWC). Size spectra from the monomodal model are represented by a gamma distribution, N(D) = N(sub o)D(exp nu)exp(-lambda D), where D = ice particle maximum dimension. The slope parameter, lambda, and the parameter N(sub o) are predicted from the IWC through the growth processes of vapor diffusion and aggregation. The model formulation is analytical, computationally efficient, and well suited for incorporation into larger models. The monomodal model has been validated against two other cirrus cloud case studies. From the monomodal size spectra, the size distributions which determine concentrations of ice particles less than about 150 mu m are predicted.

Measurements of the Ice Water Content of Cirrus in the Tropics and Subtropics. I; Instrument Details and Validation

Science.gov (United States)

Weinstock, E. M.; Smith, J. B.; Sayres, D.; Pittman, J. V.; Allen, N.; Demusz, J.; Greenberg, M.; Rivero, M.; Anderson, J. G.

2003-01-01

We describe an instrument mounted in a pallet on the NASA WB-57 aircraft that is designed to measure the sum of gas phase and solid phase water, or total water, in cirrus clouds. Using an isokinetic inlet, a 600-watt heater mounted directly in the flow, and Lyman-alpha photofragment fluorescence technique for detection, accurate measurements of total water have been made over almost three orders of magnitude. Isokinetic flow is achieved with an actively controlled roots pump by referencing aircraft pressure, temperature, and true air speed, together with instrument flow velocity, temperature, and pressure. During CRYSTAL FACE, the instrument operated at duct temperatures sufficiently warm to completely evaporate particles up to 150 microns diameter. In flight diagnostics, intercomparison with water measured by absorption in flight, as well as intercomparisons in clear air with water vapor measured by the Harvard water vapor instrument and the JPL infrared tunable diode laser hygrometer validate the detection sensitivity of the instrument and illustrate minimal hysteresis from instrument surfaces. The simultaneous measurement of total water and water vapor in cirrus clouds yields their ice water content.

Effects of stratocumulus, cumulus, and cirrus clouds on the UV-B diffuse to global ratio: Experimental and modeling results

International Nuclear Information System (INIS)

López, María Laura; Palancar, Gustavo G.; Toselli, Beatriz M.

2012-01-01

Broadband measurements of global and diffuse UV-B irradiance (280-315 nm) together with modeled and measured diffuse to global ratios (DGR) have been used to characterize the influence of different types of clouds on irradiance at the surface. Measurements were carried out during 2000-2001 in Córdoba City, Argentina. The Tropospheric Ultraviolet Visible (TUV) model was used to analyze the behavior of the modeled DGRs for different cloud optical depths and at different altitudes and solar zenith angles (SZA). Different cloud altitudes were also tested, although only the results for a cloud placed at 1.5-2.5 km of altitude are shown. A total of 16 day with stratocumulus, 12 with cumulus, and 16 with cirrus have been studied and compared among them and also against 21 clear sky days. Different behaviors were clearly detected and also differentiated through the analysis of the averages and the standard deviations of the DGRs: 1.02±0.06 for stratocumulus, 0.74±0.18 for cumulus, 0.63±0.12 for cirrus, and 0.60±0.13 for the clear sky days, respectively. Stratocumulus clouds showed a low variability in the DGR values, which were concentrated close to one at all SZAs. DGR values for cumulus clouds presented a large variability at all SZAs, mostly associated with the different optical depths. Finally, the closeness between the DGR values for cirrus clouds and the DGR values for clear days showed that these clouds generally do not strongly affect the UV-B irradiance at the surface at any SZA. In the opposite side, stratocumulus clouds were identified as those with the largest effects, at all SZAs, on the UV-B irradiance at the surface.

Tracers and traceability: implementing the cirrus parameterisation from LACM in the TOMCAT/SLIMCAT chemistry transport model as an example of the application of quality assurance to legacy models

Directory of Open Access Journals (Sweden)

A. M. Horseman

2010-03-01

Full Text Available A new modelling tool for the investigation of large-scale behaviour of cirrus clouds has been developed. This combines two existing models, the TOMCAT/SLIMCAT chemistry transport model (nupdate library version 0.80, script mpc346_l and cirrus parameterisation of Ren and MacKenzie (LACM implementation not versioned. The development process employed a subset of best-practice software engineering and quality assurance processes, selected to be viable for small-scale projects whilst maintaining the same traceability objectives. The application of the software engineering and quality control processes during the development has been shown to be not a great overhead, and their use has been of benefit to the developers as well as the end users of the results. We provide a step-by-step guide to the implementation of traceability tailored to the production of geo-scientific research software, as distinct from commercial and operational software. Our recommendations include: maintaining a living "requirements list"; explicit consideration of unit, integration and acceptance testing; and automated revision/configuration control, including control of analysis tool scripts and programs.

Initial testing of the resulting model against satellite and in-situ measurements has been promising. The model produces representative results for both spatial distribution of the frequency of occurrence of cirrus ice, and the drying of air as it moves across the tropical tropopause. The model is now ready for more rigorous quantitative testing, but will require the addition of a vertical wind velocity downscaling scheme to better represent extra-tropical continental cirrus.

An international capstone experience for pharmacy students.

Science.gov (United States)

Gourley, Dick R; Vaidya, Varun A; Hufstader, Meghan A; Ray, Max D; Chisholm-Burns, Marie A

2013-04-12

This report describes the experiences of the University of Tennessee College of Pharmacy over 20 years with an international capstone educational experience for students. Although the university provides reciprocal opportunities to international students, this report focuses on the experiences of the college's pharmacy students who have participated in the program. This capstone course is offered as an elective course in the advanced pharmacy practice experience (APPE) component of the college's experiential program. Goals of the program and a brief description of its organizational structure are provided. Results of a structured student satisfaction survey and a survey covering the most recent 3 years of the program are presented. This program has greatly broadened participants' cultural horizons and expanded their global view and understanding of the contributions of pharmacy to health care.

Experience with mechanical segmentation of reactor internals

International Nuclear Information System (INIS)

Carlson, R.; Hedin, G.

2003-01-01

Operating experience from BWE:s world-wide has shown that many plants experience initial cracking of the reactor internals after approximately 20 to 25 years of service life. This ''mid-life crisis'', considering a plant design life of 40 years, is now being addressed by many utilities. Successful resolution of these issues should give many more years of trouble-free operation. Replacement of reactor internals could be, in many cases, the most favourable option to achieve this. The proactive strategy of many utilities to replace internals in a planned way is a market-driven effort to minimize the overall costs for power generation, including time spent for handling contingencies and unplanned outages. Based on technical analyses, knowledge about component market prices and in-house costs, a cost-effective, optimized strategy for inspection, mitigation and replacements can be implemented. Also decommissioning of nuclear plants has become a reality for many utilities as numerous plants worldwide are closed due to age and/or other reasons. These facts address a need for safe, fast and cost-effective methods for segmentation of internals. Westinghouse has over the last years developed methods for segmentation of internals and has also carried out successful segmentation projects. Our experience from the segmentation business for Nordic BWR:s is that the most important parameters to consider when choosing a method and equipment for a segmentation project are: - Safety, - Cost-effectiveness, - Cleanliness, - Reliability. (orig.)

Impact of varying lidar measurement and data processing techniques in evaluating cirrus cloud and aerosol direct radiative effects

Directory of Open Access Journals (Sweden)

S. Lolli

2018-03-01

Full Text Available In the past 2 decades, ground-based lidar networks have drastically increased in scope and relevance, thanks primarily to the advent of lidar observations from space and their need for validation. Lidar observations of aerosol and cloud geometrical, optical and microphysical atmospheric properties are subsequently used to evaluate their direct radiative effects on climate. However, the retrievals are strongly dependent on the lidar instrument measurement technique and subsequent data processing methodologies. In this paper, we evaluate the discrepancies between the use of Raman and elastic lidar measurement techniques and corresponding data processing methods for two aerosol layers in the free troposphere and for two cirrus clouds with different optical depths. Results show that the different lidar techniques are responsible for discrepancies in the model-derived direct radiative effects for biomass burning (0.05 W m−2 at surface and 0.007 W m−2 at top of the atmosphere and dust aerosol layers (0.7 W m−2 at surface and 0.85 W m−2 at top of the atmosphere. Data processing is further responsible for discrepancies in both thin (0.55 W m−2 at surface and 2.7 W m−2 at top of the atmosphere and opaque (7.7 W m−2 at surface and 11.8 W m−2 at top of the atmosphere cirrus clouds. Direct radiative effect discrepancies can be attributed to the larger variability of the lidar ratio for aerosols (20–150 sr than for clouds (20–35 sr. For this reason, the influence of the applied lidar technique plays a more fundamental role in aerosol monitoring because the lidar ratio must be retrieved with relatively high accuracy. In contrast, for cirrus clouds, with the lidar ratio being much less variable, the data processing is critical because smoothing it modifies the aerosol and cloud vertically resolved extinction profile that is used as input to compute direct radiative effect calculations.

Impact of varying lidar measurement and data processing techniques in evaluating cirrus cloud and aerosol direct radiative effects

Science.gov (United States)

Lolli, Simone; Madonna, Fabio; Rosoldi, Marco; Campbell, James R.; Welton, Ellsworth J.; Lewis, Jasper R.; Gu, Yu; Pappalardo, Gelsomina

2018-03-01

In the past 2 decades, ground-based lidar networks have drastically increased in scope and relevance, thanks primarily to the advent of lidar observations from space and their need for validation. Lidar observations of aerosol and cloud geometrical, optical and microphysical atmospheric properties are subsequently used to evaluate their direct radiative effects on climate. However, the retrievals are strongly dependent on the lidar instrument measurement technique and subsequent data processing methodologies. In this paper, we evaluate the discrepancies between the use of Raman and elastic lidar measurement techniques and corresponding data processing methods for two aerosol layers in the free troposphere and for two cirrus clouds with different optical depths. Results show that the different lidar techniques are responsible for discrepancies in the model-derived direct radiative effects for biomass burning (0.05 W m-2 at surface and 0.007 W m-2 at top of the atmosphere) and dust aerosol layers (0.7 W m-2 at surface and 0.85 W m-2 at top of the atmosphere). Data processing is further responsible for discrepancies in both thin (0.55 W m-2 at surface and 2.7 W m-2 at top of the atmosphere) and opaque (7.7 W m-2 at surface and 11.8 W m-2 at top of the atmosphere) cirrus clouds. Direct radiative effect discrepancies can be attributed to the larger variability of the lidar ratio for aerosols (20-150 sr) than for clouds (20-35 sr). For this reason, the influence of the applied lidar technique plays a more fundamental role in aerosol monitoring because the lidar ratio must be retrieved with relatively high accuracy. In contrast, for cirrus clouds, with the lidar ratio being much less variable, the data processing is critical because smoothing it modifies the aerosol and cloud vertically resolved extinction profile that is used as input to compute direct radiative effect calculations.

First internal and external experiments at COSY Juelich

International Nuclear Information System (INIS)

Prasuhn, D.; Maier, R.; Bechstedt, U.; Dietrich, J.; Hacker, U.; Martin, S.; Stockhorst, H.; Toelle, R.; Grzonka, D.; Nake, C.; Mosel, F.

1995-01-01

The inauguration of the cooler synchrotron COSY Juelich was celebrated on April 1st, 1993. After the first successful acceleration to proton momenta above 800 GeV/c, beamtimes for experiments were scheduled in parallel to further machine development. The first experiment was the internal target experiment EDDA, which investigated the energy dependence of the p-p interaction. It makes use of a 3x4 μm 2 thin CH 2 fiber as an internal target. The thickness of the fiber is more than adequate to achieve high luminosities, so the intensity of the stored beam has to be reduced to 10 7 p. On the other hand, it is thin enough to achieve beam lifetimes of 3 s at 1.4 GeV/c. Details of the target fabrication and the first experimental results will be discussed. Both external experimental facilities at COSY, the time-of-flight spectrometer, and the magnetic spectrometer BIG KARL use a liquid hydrogen (deuterium) target. The first experiments were carried out at proton energies between 300 MeV and 500 MeV. Also, these experimental data will be presented. Two further internal experiments are prepared for the installation into the COSY ring. The target for the first experiment is a gas-jet target, the second experiment uses ribbon targets for the interaction. The status of both experimental setups will be shown. (orig.)

Potential of remote sensing of cirrus optical thickness by airborne spectral radiance measurements at different sideward viewing angles

OpenAIRE

Wolf, Kevin; Ehrlich, André; Hüneke, Tilman; Pfeilsticker, Klaus; Werner, Frank; Wirth, Martin; Wendisch, Manfred

2017-01-01

Spectral radiance measurements collected in nadir and sideward viewing directions by two airborne passive solar remote sensing instruments, the Spectral Modular Airborne Radiation measurement sysTem (SMART) and the Differential Optical Absorption Spectrometer (mini-DOAS), are used to compare the remote sensing results of cirrus optical thickness τ. The comparison is based on a sensitivity study using radiative transfer simulations (RTS) and on data obtained during three airb...

In real time: exploring nursing students' learning during an international experience.

Science.gov (United States)

Afriyie Asenso, Barbara; Reimer-Kirkham, Sheryl; Astle, Barbara

2013-10-11

Abstract Nursing education has increasingly turned to international learning experiences to educate students who are globally minded and aware of social injustices in local and global communities. To date, research with international learning experiences has focused on the benefits for the students participating, after they have completed the international experience. The purpose of this qualitative study was to explore how nursing students learn during the international experience. The sample consisted of eight nursing students who enrolled in an international learning experience, and data were collected in "real time" in Zambia. The students were observed during learning activities and were interviewed three times. Three major themes emerged from the thematic analysis: expectations shaped students' learning, engagement facilitated learning, and critical reflection enhanced learning. Implications are discussed, related to disrupting media representations of Africa that shape students' expectations, and educational strategies for transformative learning and global citizenship.

First internal and external experiments at COSY Juelich

Energy Technology Data Exchange (ETDEWEB)

Prasuhn, D [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Maier, R [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Bechstedt, U [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Dietrich, J [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Hacker, U [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Martin, S [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Stockhorst, H [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Toelle, R [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Grzonka, D [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Nake, C [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Mosel, F [Bonn Univ. (Germany). Inst. fuer Strahlen- und Kernphysik

1995-08-01

The inauguration of the cooler synchrotron COSY Juelich was celebrated on April 1st, 1993. After the first successful acceleration to proton momenta above 800 GeV/c, beamtimes for experiments were scheduled in parallel to further machine development. The first experiment was the internal target experiment EDDA, which investigated the energy dependence of the p-p interaction. It makes use of a 3x4 {mu}m{sup 2} thin CH{sub 2} fiber as an internal target. The thickness of the fiber is more than adequate to achieve high luminosities, so the intensity of the stored beam has to be reduced to 10{sup 7} p. On the other hand, it is thin enough to achieve beam lifetimes of 3 s at 1.4 GeV/c. Details of the target fabrication and the first experimental results will be discussed. Both external experimental facilities at COSY, the time-of-flight spectrometer, and the magnetic spectrometer BIG KARL use a liquid hydrogen (deuterium) target. The first experiments were carried out at proton energies between 300 MeV and 500 MeV. Also, these experimental data will be presented. Two further internal experiments are prepared for the installation into the COSY ring. The target for the first experiment is a gas-jet target, the second experiment uses ribbon targets for the interaction. The status of both experimental setups will be shown. (orig.).

In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus

Science.gov (United States)

Kuhn, Thomas; Heymsfield, Andrew J.

2016-09-01

Cirrus clouds reflect incoming solar radiation, creating a cooling effect. At the same time, these clouds absorb the infrared radiation from the Earth, creating a greenhouse effect. The net effect, crucial for radiative transfer, depends on the cirrus microphysical properties, such as particle size distributions and particle shapes. Knowledge of these cloud properties is also needed for calibrating and validating passive and active remote sensors. Ice particles of sizes below 100 µm are inherently difficult to measure with aircraft-mounted probes due to issues with resolution, sizing, and size-dependent sampling volume. Furthermore, artefacts are produced by shattering of particles on the leading surfaces of the aircraft probes when particles several hundred microns or larger are present. Here, we report on a series of balloon-borne in situ measurements that were carried out at a high-latitude location, Kiruna in northern Sweden (68N 21E). The method used here avoids these issues experienced with the aircraft probes. Furthermore, with a balloon-borne instrument, data are collected as vertical profiles, more useful for calibrating or evaluating remote sensing measurements than data collected along horizontal traverses. Particles are collected on an oil-coated film at a sampling speed given directly by the ascending rate of the balloon, 4 m s-1. The collecting film is advanced uniformly inside the instrument so that an always unused section of the film is exposed to ice particles, which are measured by imaging shortly after sampling. The high optical resolution of about 4 µm together with a pixel resolution of 1.65 µm allows particle detection at sizes of 10 µm and larger. For particles that are 20 µm (12 pixel) in size or larger, the shape can be recognized. The sampling volume, 130 cm3 s-1, is well defined and independent of particle size. With the encountered number concentrations of between 4 and 400 L-1, this required about 90- to 4-s sampling times to

International Reactor Physics Experiment Evaluation (IRPhE) Project

International Nuclear Information System (INIS)

2013-01-01

The International Reactor Physics Experiment Evaluation (IRPhE) Project aims to provide the nuclear community with qualified benchmark data sets by collecting reactor physics experimental data from nuclear facilities, worldwide. More specifically the objectives of the expert group are as follows: - maintaining an inventory of the experiments that have been carried out and documented; - archiving the primary documents and data released in computer-readable form; - promoting the use of the format and methods developed and seek to have them adopted as a standard. For those experiments where interest and priority is expressed by member countries or working parties and executive groups within the NEA provide guidance or co-ordination in: - compiling experiments into a standard international agreed format; - verifying the data, to the extent possible, by reviewing original and subsequently revised documentation, and by consulting with the experimenters or individuals who are familiar with the experimenters or the experimental facility; - analysing and interpreting the experiments with current state-of-the-art methods; - publishing electronically the benchmark evaluations. The expert group will: - identify gaps in data and provide guidance on priorities for future experiments; - involve the young generation (Masters and PhD students and young researchers) to find an effective way of transferring know-how in experimental techniques and analysis methods; - provide a tool for improved exploitation of completed experiments for Generation IV reactors; - coordinate closely its work with other NSC experimental work groups in particular the International Criticality Safety Benchmark Evaluation Project (ICSBEP), the Shielding Integral Benchmark Experiment Data Base (SINBAD) and others, e.g. knowledge preservation in fast reactors of the IAEA, the ANS Joint Benchmark Activities; - keep a close link with the working parties on scientific issues of reactor systems (WPRS), the expert

Heterogeneous Ice Nucleation Ability of NaCl and Sea Salt Aerosol Particles at Cirrus Temperatures

Science.gov (United States)

Wagner, Robert; Kaufmann, Julia; Möhler, Ottmar; Saathoff, Harald; Schnaiter, Martin; Ullrich, Romy; Leisner, Thomas

2018-03-01

In situ measurements of the composition of heterogeneous cirrus ice cloud residuals have indicated a substantial contribution of sea salt in sampling regions above the ocean. We have investigated the heterogeneous ice nucleation ability of sodium chloride (NaCl) and sea salt aerosol (SSA) particles at cirrus cloud temperatures between 235 and 200 K in the Aerosol Interaction and Dynamics in the Atmosphere aerosol and cloud chamber. Effloresced NaCl particles were found to act as ice nucleating particles in the deposition nucleation mode at temperatures below about 225 K, with freezing onsets in terms of the ice saturation ratio, Sice, between 1.28 and 1.40. Above 225 K, the crystalline NaCl particles deliquesced and nucleated ice homogeneously. The heterogeneous ice nucleation efficiency was rather similar for the two crystalline forms of NaCl (anhydrous NaCl and NaCl dihydrate). Mixed-phase (solid/liquid) SSA particles were found to act as ice nucleating particles in the immersion freezing mode at temperatures below about 220 K, with freezing onsets in terms of Sice between 1.24 and 1.42. Above 220 K, the SSA particles fully deliquesced and nucleated ice homogeneously. Ice nucleation active surface site densities of the SSA particles were found to be in the range between 1.0 · 1010 and 1.0 · 1011 m-2 at T < 220 K. These values are of the same order of magnitude as ice nucleation active surface site densities recently determined for desert dust, suggesting a potential contribution of SSA particles to low-temperature heterogeneous ice nucleation in the atmosphere.

On the regional climatic impact of contrails: microphysical and radiative properties of contrails and natural cirrus clouds

Directory of Open Access Journals (Sweden)

B. Strauss

Full Text Available The impact of contrail-induced cirrus clouds on regional climate is estimated for mean atmospheric conditions of southern Germany in the months of July and October. This is done by use of a regionalized one-dimensional radiative convective model (RCM. The influence of an increased ice cloud cover is studied by comparing RCM results representing climatological values with a modified case. In order to study the sensitivity of this effect on the radiative characteristics of the ice cloud, two types of additional ice clouds were modelled: cirrus and contrails, the latter cloud type containing a higher number of smaller and less of the larger cloud particles. Ice cloud parameters are calculated on the basis of a particle size distribution which covers the range from 2 to 2000 µm, taking into consideration recent measurements which show a remarkable amount of particles smaller than 20 µm. It turns out that a 10% increase in ice cloud cover leads to a surface temperature increase in the order of 1K, ranging from 1.1 to 1.2K in July and from 0.8 to 0.9K in October depending on the radiative characteristics of the air-traffic-induced ice clouds. Modelling the current contrail cloud cover which is near 0.5% over Europe yields a surface temperature increase in the order of 0.05K.

On the regional climatic impact of contrails: microphysical and radiative properties of contrails and natural cirrus clouds

Directory of Open Access Journals (Sweden)

B. Strauss

1997-11-01

Full Text Available The impact of contrail-induced cirrus clouds on regional climate is estimated for mean atmospheric conditions of southern Germany in the months of July and October. This is done by use of a regionalized one-dimensional radiative convective model (RCM. The influence of an increased ice cloud cover is studied by comparing RCM results representing climatological values with a modified case. In order to study the sensitivity of this effect on the radiative characteristics of the ice cloud, two types of additional ice clouds were modelled: cirrus and contrails, the latter cloud type containing a higher number of smaller and less of the larger cloud particles. Ice cloud parameters are calculated on the basis of a particle size distribution which covers the range from 2 to 2000 µm, taking into consideration recent measurements which show a remarkable amount of particles smaller than 20 µm. It turns out that a 10% increase in ice cloud cover leads to a surface temperature increase in the order of 1K, ranging from 1.1 to 1.2K in July and from 0.8 to 0.9K in October depending on the radiative characteristics of the air-traffic-induced ice clouds. Modelling the current contrail cloud cover which is near 0.5% over Europe yields a surface temperature increase in the order of 0.05K.

Foreign experience of regulating international trade transactions

Directory of Open Access Journals (Sweden)

Klymenko L. V.

2015-05-01

Full Text Available The article deals with the international experience of state regulating international trade transactions; nature, directions and contradictions of contemporary processes of globalization are defined; components of regulatory and incentive means in system of state supporting foreign trade activity of commodity producers are considered; general provisions for the improvement of state regulation mechanisms of export-import activities in Ukraine are determined.

Improving the International Student Experience in Australia through Embedded Peer Mentoring

Science.gov (United States)

Outhred, Tim; Chester, Andrea

2013-01-01

As Australia endeavors to sustain growth of its international education industry, there have been major concerns regarding the experience of international students. This review examines the international student experience in Australia, particularly issues surrounding study-work-life balance (SWLB), acculturation, health, and well-being. The…

International Students' Experiences of Integrating into the Workforce

Science.gov (United States)

Nunes, Sarah; Arthur, Nancy

2013-01-01

This study explored the integration experiences of 16 international students entering the Canadian workforce using a semistructured interview and constant comparison method. The international students were pursuing immigration to Canada, despite unmet job prospects. Students recommended that employers refrain from discriminating against students…

International Students' Experiences of University Libraries and Librarians

Science.gov (United States)

Hughes, Hilary

2010-01-01

International students constitute a significant proportion of the Australian university population, and thus of the university library-using population. Drawing on qualitative research findings, this paper discusses the library-related experiences and perceptions of international students at two Australian universities. While the students'…

Does clerkship experience influence interest In internal medicine ...

African Journals Online (AJOL)

BACKGROUND:The career intention of undergraduate medical students may be influenced by the clerkship experience in the various specialties. AIM:This study was undertaken to assess the medical student's perception of the internal medicine clerkship and determine its influence in the choice of internal medicine as a ...

Ice nucleation in sulfuric acid/organic aerosols: implications for cirrus cloud formation

Directory of Open Access Journals (Sweden)

M. R. Beaver

2006-01-01

Full Text Available Using an aerosol flow tube apparatus, we have studied the effects of aliphatic aldehydes (C3 to C10 and ketones (C3 and C9 on ice nucleation in sulfuric acid aerosols. Mixed aerosols were prepared by combining an organic vapor flow with a flow of sulfuric acid aerosols over a small mixing time (~60 s at room temperature. No acid-catalyzed reactions were observed under these conditions, and physical uptake was responsible for the organic content of the sulfuric acid aerosols. In these experiments, aerosol organic content, determined by a Mie scattering analysis, was found to vary with the partial pressure of organic, the flow tube temperature, and the identity of the organic compound. The physical properties of the organic compounds (primarily the solubility and melting point were found to play a dominant role in determining the inferred mode of nucleation (homogenous or heterogeneous and the specific freezing temperatures observed. Overall, very soluble, low-melting organics, such as acetone and propanal, caused a decrease in aerosol ice nucleation temperatures when compared with aqueous sulfuric acid aerosol. In contrast, sulfuric acid particles exposed to organic compounds of eight carbons and greater, of much lower solubility and higher melting temperatures, nucleate ice at temperatures above aqueous sulfuric acid aerosols. Organic compounds of intermediate carbon chain length, C4-C7, (of intermediate solubility and melting temperatures nucleated ice at the same temperature as aqueous sulfuric acid aerosols. Interpretations and implications of these results for cirrus cloud formation are discussed.

International exchange training in genetic counseling: an exploration of the value in exchange experiences.

Science.gov (United States)

Alexander, Chelsea K A; Veach, Patricia McCarthy; Lian, Fengqin; LeRoy, Bonnie S

2013-12-01

International exchange training in genetic counseling is increasing, but research examining these experiences is lacking. In this study 309 genetic counseling students and genetic counselors completed an anonymous survey investigating six major research questions: (1) How prevalent are international genetic counseling experiences? (2) What types are pursued and why? (3) What supports and barriers exist? 3) What are the demographic characteristics of individuals accruing international experience? (5) Does international experience promote professional development? and (6) Do genetic counseling students and professionals perceive international experiences as beneficial? Most respondents were Caucasian females born in one of 25 countries. The most prevalent experiences involved either clinical observation or clinical training. Common motivations for pursuing international experience were personal growth, exposure to a different healthcare system, and travel opportunities. Outcomes included professionally-relevant experience and personal growth. Barriers included finances, limited availability of opportunities, and for those without international experience, family responsibilities. Additional findings, practice and training implications, and research recommendations are provided.

Internal marketing: creating quality employee experiences in health care organizations.

Science.gov (United States)

Masri, Maysoun Dimachkie; Oetjen, Dawn; Rotarius, Timothy

2011-01-01

To cope with the recent challenges within the health care industry, health care managers need to engage in the internal marketing of their various services. Internal marketing has been used as an effective management tool to increase employees' motivation, satisfaction, and productivity (J Mark Commun. 2010;16(5):325-344). Health care managers should understand that an intense focus on internal marketing factors will lead to a quality experience for employees that will ultimately have a positive effect on the patient experiences.

Exploring the Experiences of International Students in China

Science.gov (United States)

Ding, Xiaojiong

2016-01-01

In recent years, China has grown from an insignificant player to a major destination in the global market for international students. Based on a questionnaire survey and in-depth interviews conducted in 2013, this study uses Shanghai as an example to examine international students' experiences in China. It is found that China has become a niche…

Status report on the International Germanium Experiment

International Nuclear Information System (INIS)

Brodzinski, R.L.; Avignone, F.T.; Collar, J.I.; Courant, H.; Garcia, E.; Guerard, C.K.; Hensley, W.K.; Kirpichnikov, I.V.; Miley, H.S.; Morales, A.; Morales, J.; Nunez-Lagos, R.; Osetrov, S.B.; Pogosov, V.S.; Pomansky, A.A.; Puimedon, J.; Reeves, J.H.; Ruddick, K.; Saenz, C.; Salinas, A.; Sarsa, M.L.; Smolnikov, A.A.; Starostin, A.S.; Tamanyan, A.G.; Vasiliev, S.I.; Villar, J.A.

1993-01-01

Phase II detector fabrication for the International Germanium Experiment is in progress. Sources of background observed during Phase I are discussed. Cosmogenic 7 Be is measured in germanium. Radium contamination, presumably in electroformed copper, is reported. (orig.)

Status report on the International Germanium Experiment

Energy Technology Data Exchange (ETDEWEB)

Brodzinski, R L; Avignone, F.T.; Collar, J I; Courant, H; Garcia, E; Guerard, C K; Hensley, W K; Kirpichnikov, I V; Miley, H S; Morales, A; Morales, J; Nunez-Lagos, R; Osetrov, S B; Pogosov, V S; Pomansky, A A; Puimedon, J; Reeves, J H; Ruddick, K; Saenz, C; Salinas, A; Sarsa, M L; Smolnikov, A A; Starostin, A S; Tamanyan, A G; Vasiliev, S I; Villar, J A [Pacific Northwest Lab., Richland, WA (United States) Univ. of South Carolina, Columbia, SC (United States) Univ. of Minnesota, Minneapolis, MN (United States) Univ. of Zaragoza (Spain) Inst. for Theoretical and Experimental Physics, Moscow (Russian Federation) Inst. for Nuclear Research, Baksan Neutrino Observatory (Russian Federation) Yerevan Physical Inst., Yerevan (Armenia)

1993-04-01

Phase II detector fabrication for the International Germanium Experiment is in progress. Sources of background observed during Phase I are discussed. Cosmogenic [sup 7]Be is measured in germanium. Radium contamination, presumably in electroformed copper, is reported. (orig.)

Modelling of cirrus clouds – Part 2: Competition of different nucleation mechanisms

Directory of Open Access Journals (Sweden)

P. Spichtinger

2009-04-01

Full Text Available We study the competition of two different freezing mechanisms (homogeneous and heterogeneous freezing in the same environment for cold cirrus clouds. To this goal we use the recently developed and validated ice microphysics scheme (Spichtinger and Gierens, 2009a which distinguishes between ice classes according to their formation process. We investigate cases with purely homogeneous ice formation and compare them with cases where background ice nuclei in varying concentration heterogeneously form ice prior to homogeneous nucleation. We perform additionally a couple of sensitivity studies regarding threshold humidity for heterogeneous freezing, uplift speed, and ambient temperature, and we study the influence of random motions induced by temperature fluctuations in the clouds. We find three types of cloud evolution, homogeneously dominated, heterogeneously dominated, and a mixed type where neither nucleation process dominates. The latter case is prone to long–lasting in–cloud ice supersaturation of the order 30% and more.

Enhancing Student International Awareness and Global Competency through Compact International Experience Courses

Science.gov (United States)

Jacobitz, Frank; Schubert, Thomas

2013-11-01

Short-term, study-abroad, elective engineering courses were developed in order to raise the international awareness and global competency of engineering students. These Compact International Experience (CIE) courses were taught in response to a strong student desire for engineering study abroad courses and an effort by the home institution to internationalize its curriculum. An assessment of repeat offerings of two three-semester-unit courses on Topics in Fluid Mechanics and Advanced Electronic Circuit Design in a three-week time frame in France and Australia was performed. The goals of the two CIE courses are an effective teaching of their respective technical content as well as a student understanding of the cultural environment and the impact of engineering solutions from a global and societal viewpoint. In the repeat offerings, increased interaction with local industry was an additional goal. The CIE courses were assessed through surveys completed at the beginning and end of the courses, weekly student reflection papers, course evaluations, and formalized instructor observations. Based on the assessment performed, the two CIE courses have been found to be a valuable approach in the delivery of engineering technical electives combined with an international experience.

Student experiences with an international public health exchange project.

Science.gov (United States)

Critchley, Kim A; Richardson, Eileen; Aarts, Clara; Campbell, Barbara; Hemmingway, Ann; Koskinen, Liisa; Mitchell, Maureen P; Nordstrom, Pam

2009-01-01

With growing interconnectivity of healthcare systems worldwide and increased immigration, inappropriate cultural and role assumptions are often seen when cultures clash within a country or when there is practice across country boundaries in times of disaster and during international travel. To increase students' multicultural awareness and work experiences abroad, the authors describe a 7-school, 5-country international student exchange project. The authors also share the students' evaluations of their experiences as they are challenged to erase boundaries and embrace nursing across countries. Participating faculty describe the process, challenges, and keys to success found in creating and living this international project. Students involved in the exchange process evaluate the learning opportunities and challenges and the joy of coming together as newfound colleagues and friends.

Sensitivity of surface temperature to radiative forcing by contrail cirrus in a radiative-mixing model

Directory of Open Access Journals (Sweden)

U. Schumann

2017-11-01

Full Text Available Earth's surface temperature sensitivity to radiative forcing (RF by contrail cirrus and the related RF efficacy relative to CO2 are investigated in a one-dimensional idealized model of the atmosphere. The model includes energy transport by shortwave (SW and longwave (LW radiation and by mixing in an otherwise fixed reference atmosphere (no other feedbacks. Mixing includes convective adjustment and turbulent diffusion, where the latter is related to the vertical component of mixing by large-scale eddies. The conceptual study shows that the surface temperature sensitivity to given contrail RF depends strongly on the timescales of energy transport by mixing and radiation. The timescales are derived for steady layered heating (ghost forcing and for a transient contrail cirrus case. The radiative timescales are shortest at the surface and shorter in the troposphere than in the mid-stratosphere. Without mixing, a large part of the energy induced into the upper troposphere by radiation due to contrails or similar disturbances gets lost to space before it can contribute to surface warming. Because of the different radiative forcing at the surface and at top of atmosphere (TOA and different radiative heating rate profiles in the troposphere, the local surface temperature sensitivity to stratosphere-adjusted RF is larger for SW than for LW contrail forcing. Without mixing, the surface energy budget is more important for surface warming than the TOA budget. Hence, surface warming by contrails is smaller than suggested by the net RF at TOA. For zero mixing, cooling by contrails cannot be excluded. This may in part explain low efficacy values for contrails found in previous global circulation model studies. Possible implications of this study are discussed. Since the results of this study are model dependent, they should be tested with a comprehensive climate model in the future.

Arab International Students' Experiences in a U.S. University

Science.gov (United States)

Abo Rabia, Hazza M.

2015-01-01

This qualitative, exploratory study described the experiences of Arab international students in a U.S. postsecondary institution. This research identified those factors that Arab international students reported as facilitating or obstructing their academic success, promoting or limiting their socialization within the context of their postsecondary…

International assignment and repatriation experiences of Indian international assignees in the Netherlands

NARCIS (Netherlands)

Valk, R.; van der Velde, M.; van Engen, M.L.; Szkudlarek, B.

2013-01-01

Purpose The purpose of this paper is to explore the influence of cultural identity change, organizational and social support and cultural distance on repatriation experiences of Indian international assignees. Design/methodology/approach Semi‐structured interviews were held with 19 Indians on

Cirrus Cloud Optical and Microphysical Property Retrievals from eMAS During SEAC4RS Using Bi-Spectral Reflectance Measurements Within the 1.88 micron Water Vapor Absorption Band

Science.gov (United States)

Meyer, K.; Platnick, S.; Arnold, G. T.; Holz, R. E.; Veglio, P.; Yorks, J.; Wang, C.

2016-01-01

Previous bi-spectral imager retrievals of cloud optical thickness (COT) and effective particle radius (CER) based on the Nakajima and King (1990) approach, such as those of the operational MODIS cloud optical property retrieval product (MOD06), have typically paired a non-absorbing visible or near-infrared wavelength, sensitive to COT, with an absorbing shortwave or midwave infrared wavelength sensitive to CER. However, in practice it is only necessary to select two spectral channels that exhibit a strong contrast in cloud particle absorption. Here it is shown, using eMAS observations obtained during NASAs SEAC4RS field campaign, that selecting two absorbing wavelength channels within the broader 1.88 micron water vapor absorption band, namely the 1.83 and 1.93 micron channels that have sufficient differences in ice crystal single scattering albedo, can yield COT and CER retrievals for thin to moderately thick single-layer cirrus that are reasonably consistent with other solar and IR imager-based and lidar-based retrievals. A distinct advantage of this channel selection for cirrus cloud retrievals is that the below cloud water vapor absorption minimizes the surface contribution to measured cloudy TOA reflectance, in particular compared to the solar window channels used in heritage retrievals such as MOD06. This reduces retrieval uncertainty resulting from errors in the surface reflectance assumption, as well as reduces the frequency of retrieval failures for thin cirrus clouds.

INTERNATIONAL EXPERIENCE OF ORGANIZING SCHOOL NUTRITION

Directory of Open Access Journals (Sweden)

V.R. Kuchma

2008-01-01

Full Text Available The experience of organizing school nutrition in Europe and usais analyzed. It is noted that long term programs aimed at optimizing schoolchildren nutrition have a beneficial effect on the children's health, culture of their nutrition and quality of life. The importance of carrying out similar programs in Russia is beyond any doubt: according to population research, the basic principles of good nutrition are often not observed, and school breakfasts and lunches do not correspond to the age physiological needs of children and teenagers for nutrient materials and energy. In this situation, the available experience of using vitaminbenriched products as well as vitamin and mineral complexes in children will permit to quickly resolve the existing problems of the improper, and sometimes, insufficient, nutrition.Key words: school nutrition, organization, international experience.

International Experience in Upper Echelon Theory: Literature Review

Directory of Open Access Journals (Sweden)

Đerđa Dino

2017-09-01

Full Text Available Background: The international experience of top managers is an evolving research within the upper echelon theory; therefore this literature review summarizes everything made so far.

Short-Term International Internship Experiences for Future Teachers and Other Child Development Professionals

Science.gov (United States)

Miller, Kari Knutson; Gonzalez, Amber M.

2016-01-01

This paper examines outcomes associated with participation in short-term, international internship experiences. Results suggest short-term international internship experiences contribute to rich personal and professional development outcomes. Findings highlight participant challenges associated with initial internship experiences, professional…

The Experience of an International University Teacher in Australia

Science.gov (United States)

Abayadeera, Nadana

2013-01-01

Accounting and Business schools in Australia have a considerable number of international academic staff, and the teaching effectiveness of such staff is an increasingly salient issue. Many international teachers are non-native English speakers and have different teaching approaches and styles, often reflecting their own experiences as a learner in…

The internal medicine clerkship and ambulatory learning experiences: results of the 2010 clerkship directors in internal medicine survey.

Science.gov (United States)

Shaheen, Amy; Papp, Klara K; Torre, Dario

2013-01-01

Education in the ambulatory setting should be an integral part of undergraduate medical education. However, previous studies have shown education in this setting has been lacking in medical school. Ambulatory education occurs on some internal medicine clerkships. The extent of this education is unclear. The purpose of this survey was to assess the structure, curriculum, assessment methods, and barriers to implementation of ambulatory education on the internal medicine clerkship. An annual survey of institutional members of the Clerkship Directors in Internal Medicine (CDIM) was done in April 2010. The data were anonymous and descriptive statistics were used to summarize responses. Free text results were analyzed using qualitative techniques. The response rate was 75%. The majority of respondents had a required ambulatory component to the clerkship. Ambulatory experiences distinct from the inpatient internal medicine experience were common (46%). Integration with either the inpatient experiences or other departmental clerkships also occurred. The majority of ambulatory educational experiences were with generalists (74%) and/or subspecialists (45%). The most common assessment tool was the National Board of Medical Examiners (NBME) ambulatory shelf exam. Thematic analysis of the question about how practice based learning was taught elicited four major themes: Not taught; taught in the context of learning evidence based medicine; taught while learning chronic disease management with quality improvement; taught while learning about health care finance. Barriers to implementation included lack of faculty and financial resources. There have been significant increases in the amount of time dedicated to ambulatory internal medicine. The numbers of medical schools with ambulatory internal medicine education has increased. Integration of the ambulatory experiences with other clerkships such as family medicine occurs. Curriculum was varied but difficulties with dissemination

Interdependence of tropical cirrus properties and their variability

Directory of Open Access Journals (Sweden)

S. V. Sunilkumar

2008-03-01

Full Text Available The mean properties of tropical cirrus, such as cloud top, cloud base, optic centre, cloud strength/optical depth, asymmetry factor and cloud depolarization, as well as their heterogeneities are examined using lidar observations over 281 nights from a tropical station Gadanki (13.5° N, 79.2° E during the period 1998–2002. This study shows that as the cloud optical depth (τc increases the cloud becomes more asymmetric in its scattering property. The amount of asymmetry is less than 2% for very low values of (τc and increases nonlinearly with an increase in (τc. The physical properties of these clouds also show significant variation with different time scales during the course of each night. On average, while the short-term variations in (τc are in opposite phase with those of the asymmetry factor (ξ and volume depolarization ratio (δ, the long-term variation in (τc extending over a night are found to be in opposite phase with that of ξ and in-phase with that of δ. The short-term variations in δ and (τc were attributed to possible changes in the cloud particle orientation and the long period variations to cloud evolution process. The value of δ shows a pronounced variation along the vertical, with low values near the cloud top and cloud base and high values in the middle, which is attributed to the cloud dynamics.

International Research Students' Experiences in Academic Success

Science.gov (United States)

Yeoh, Joanne Sin Wei; Terry, Daniel R.

2013-01-01

The flow of international students to study in Australia increases each year. It is a challenge for students to study abroad in a different sociocultural environment, especially for postgraduate research students, as they experience numerous difficulties in an unfamiliar and vastly different study environment. A study aimed to investigate the…

Macrophysical and optical properties of midlatitude cirrus clouds from four ground-based lidars and collocated CALIOP observations

Energy Technology Data Exchange (ETDEWEB)

Dupont, Jean-Charles; Haeffelin, M.; Morille, Y.; Noel, V.; Keckhut, P.; Winker, D.; Comstock, Jennifer M.; Chervet, P.; Roblin, A.

2010-05-27

Ground-based lidar and CALIOP datasets gathered over four mid-latitude sites, two US and two French sites, are used to evaluate the consistency of cloud macrophysical and optical property climatologies that can be derived by such datasets. The consistency in average cloud height (both base and top height) between the CALIOP and ground datasets ranges from -0.4km to +0.5km. The cloud geometrical thickness distributions vary significantly between the different datasets, due in part to the original vertical resolutions of the lidar profiles. Average cloud geometrical thicknesses vary from 1.2 to 1.9km, i.e. by more than 50%. Cloud optical thickness distributions in subvisible, semi-transparent and moderate intervals differ by more than 50% between ground and space-based datasets. The cirrus clouds with 2 optical thickness below 0.1 (not included in historical cloud climatologies) represent 30-50% of the non-opaque cirrus class. The differences in average cloud base altitude between ground and CALIOP datasets of 0.0-0.1 km, 0.0-0.2 km and 0.0-0.2 km can be attributed to irregular sampling of seasonal variations in the ground-based data, to day-night differences in detection capabilities by CALIOP, and to the restriction to situations without low-level clouds in ground-based data, respectively. The cloud geometrical thicknesses are not affected by irregular sampling of seasonal variations in the ground-based data, while up to 0.0-0.2 km and 0.1-0.3 km differences can be attributed to day-night differences in detection capabilities by CALIOP, and to the restriction to situations without lowlevel clouds in ground-based data, respectively.

International Co-Operation in Control Engineering Education Using Online Experiments

Science.gov (United States)

Henry, Jim; Schaedel, Herbert M.

2005-01-01

This paper describes the international co-operation experience in teaching control engineering with laboratories being conducted remotely by students via the Internet. This paper describes how the students ran the experiments and their personal experiences with the laboratory. A tool for process identification and controller tuning based on…

Introduction to 'International Handbook of Criticality Safety Benchmark Experiments'

International Nuclear Information System (INIS)

Komuro, Yuichi

1998-01-01

The Criticality Safety Benchmark Evaluation Project (CSBEP) was initiated in 1992 by the United States Department of Energy. The project quickly became an international effort as scientists from other interested countries became involved. The International Criticality Safety Benchmark Evaluation Project (ICSBEP) is now an official activity of the Organization for Economic Cooperation and Development-Nuclear Energy Agency (OECD-NEA). 'International Handbook of Criticality Safety Benchmark Experiments' was prepared and is updated year by year by the working group of the project. This handbook contains criticality safety benchmark specifications that have been derived from experiments that were performed at various nuclear critical facilities around the world. The benchmark specifications are intended for use by criticality safety engineers to validate calculation techniques used. The author briefly introduces the informative handbook and would like to encourage Japanese engineers who are in charge of nuclear criticality safety to use the handbook. (author)

[International academic mobility program in nursing experience report].

Science.gov (United States)

de Oliveira, Mariana Gonçalves; Pagliuca, Lorita Marlena Freitag

2012-03-01

An experience of studying abroad or of academic exchange, really adds value to the professional and personal development of exchange students. This report aims to describe a student's experience in an international academic mobility program. It was developed from 2008 to 2009 in Brazil and Spain. The experiences, observations and activities of the student were emphasized believing that the training of students and researchers is not only restricted to the university and the students' home country, and that it is important to have possibilities of new experiences and differentiated knowledge. The conclusion is that this opportunity promoted a profound effect on psychological, cultural social and scientific development of the exchange student.

Properties of subvisible cirrus clouds formed by homogeneous freezing

Directory of Open Access Journals (Sweden)

B. Kärcher

2002-01-01

Full Text Available Number concentrations and mean sizes of ice crystals and derived microphysical and optical properties of subvisible cirrus clouds (SVCs formed by homogeneous freezing of supercooled aerosols are investigated as a function of temperature and updraft speed of adiabatically ascending air parcels. The properties of such clouds are insensitive to variations of the aerosol number and size distribution. Based on criteria constraining the optical extinction, sedimentation time, and existence time of SVCs, longer-lived (>10min clouds, capable of exerting a measurable radiative or chemical impact, are generated within a narrow range of updraft speeds below 1-2cm s-1 at temperatures below about 215K, with concentrations of ice crystals not exceeding 0.1cm-3. The clouds do not reach an equilibrium state because the ice crystals sediment out of the formation layer typically before the supersaturation is removed. Two important conclusions emerge from this work. First, the above characteristics of SVCs may provide an explanation for why SVCs are more common in the cold tropical than in the warmer midlatitude tropopause region. Second, it seems likely that a limited number (-3 of effective heterogeneous freezing nuclei that nucleate ice below the homogeneous freezing threshold can control the formation and properties of SVCs, although homogeneous freezing nuclei are far more abundant.

International experience of green development in Western China

NARCIS (Netherlands)

Zhen, Lin; Hu, Jie; Du, Bingzhen; Liu, Jiyuan; Sun, Chuanzhun; Wu, Ruizi; Long, Xin; Zhang, Qiang

2015-01-01

Green development emphasizes co-development between economic and environmental dimensions, and is a peoplecentered sustainable development approach. Western China demands green development, and international experience could provide necessary, unique and important help and support for Western

Transformative Learning Experiences of International Graduate Students from Asian Countries

Science.gov (United States)

Kumi-Yeboah, Alex; James, Waynne

2014-01-01

This article investigates the transformative learning experiences of international graduate students from Asian countries. Data collection consisted of quantitative and qualitative methods. Participants included international graduate students from Asia, in the Colleges of Arts and Sciences and Engineering. Overall, 82.3% of the participants…

The shield of professional status: Comparing internationally educated nurses' and international medical graduates' experiences of discrimination.

Science.gov (United States)

Neiterman, Elena; Bourgeault, Ivy Lynn

2015-11-01

This article examines the intersecting roles of gender, ethnicity, and professional status in shaping the experiences of internationally educated health professionals in Canada. The article is based on 140 semi-structured qualitative interviews with internationally trained nurses and physicians who came to Canada within past 10 years with the intention to practice their profession. Describing the challenging process of professional integration in Canada, our participants highlighted incidents of discrimination they experienced along the way. Although some of the participants from both professional groups experienced racial discrimination, the context of those experiences differed. Physicians rarely reported instances of discrimination in communication with patients or nurses. Instead, they were concerned with instances of discrimination within their own professional group. Nurses, on the other hand, reported discrimination at the hands of patients and their families as well as racialization by physicians, management, and other nurses. We conclude our article with a reflection on the role that gender and professional status play in shaping the experiences of ethnic discrimination of internationally educated health professionals. © The Author(s) 2015.

Application of a multiple scattering model to estimate optical depth, lidar ratio and ice crystal effective radius of cirrus clouds observed with lidar.

Science.gov (United States)

Gouveia, Diego; Baars, Holger; Seifert, Patric; Wandinger, Ulla; Barbosa, Henrique; Barja, Boris; Artaxo, Paulo; Lopes, Fabio; Landulfo, Eduardo; Ansmann, Albert

2018-04-01

Lidar measurements of cirrus clouds are highly influenced by multiple scattering (MS). We therefore developed an iterative approach to correct elastic backscatter lidar signals for multiple scattering to obtain best estimates of single-scattering cloud optical depth and lidar ratio as well as of the ice crystal effective radius. The approach is based on the exploration of the effect of MS on the molecular backscatter signal returned from above cloud top.

A methodology for in-situ and remote sensing of microphysical and radiative properties of contrails as they evolve into cirrus

Science.gov (United States)

Jones, H. M.; Haywood, J.; Marenco, F.; O'Sullivan, D.; Meyer, J.; Thorpe, R.; Gallagher, M. W.; Krämer, M.; Bower, K. N.; Rädel, G.; Rap, A.; Woolley, A.; Forster, P.; Coe, H.

2012-09-01

Contrails and especially their evolution into cirrus-like clouds are thought to have very important effects on local and global radiation budgets, though are generally not well represented in global climate models. Lack of contrail parameterisations is due to the limited availability of in situ contrail measurements which are difficult to obtain. Here we present a methodology for successful sampling and interpretation of contrail microphysical and radiative data using both in situ and remote sensing instrumentation on board the FAAM BAe146 UK research aircraft as part of the COntrails Spreading Into Cirrus (COSIC) study. Forecast models were utilised to determine flight regions suitable for contrail formation and sampling; regions that were both free of cloud but showed a high probability of occurrence of air mass being supersaturated with respect to ice. The FAAM research aircraft, fitted with cloud microphysics probes and remote sensing instruments, formed a distinctive spiral-shaped contrail in the predicted area by flying in an orbit over the same ground position as the wind advected the contrails to the east. Parts of these contrails were sampled during the completion of four orbits, with sampled contrail regions being between 7 and 30 min old. Lidar measurements were useful for in-flight determination of the location and spatial extent of the contrails, and also to report extinction values that agreed well with those calculated from the microphysical data. A shortwave spectrometer was also able to detect the contrails, though the signal was weak due to the dispersion and evaporation of the contrails. Post-flight the UK Met Office NAME III dispersion model was successfully used as a tool for modelling the dispersion of the persistent contrail; determining its location and age, and determining when there was interference from other measured aircraft contrails or when cirrus encroached on the area later in the flight. The persistent contrails were found to

A methodology for in-situ and remote sensing of microphysical and radiative properties of contrails as they evolve into cirrus

Directory of Open Access Journals (Sweden)

H. M. Jones

2012-09-01

Full Text Available Contrails and especially their evolution into cirrus-like clouds are thought to have very important effects on local and global radiation budgets, though are generally not well represented in global climate models. Lack of contrail parameterisations is due to the limited availability of in situ contrail measurements which are difficult to obtain. Here we present a methodology for successful sampling and interpretation of contrail microphysical and radiative data using both in situ and remote sensing instrumentation on board the FAAM BAe146 UK research aircraft as part of the COntrails Spreading Into Cirrus (COSIC study.

Forecast models were utilised to determine flight regions suitable for contrail formation and sampling; regions that were both free of cloud but showed a high probability of occurrence of air mass being supersaturated with respect to ice. The FAAM research aircraft, fitted with cloud microphysics probes and remote sensing instruments, formed a distinctive spiral-shaped contrail in the predicted area by flying in an orbit over the same ground position as the wind advected the contrails to the east. Parts of these contrails were sampled during the completion of four orbits, with sampled contrail regions being between 7 and 30 min old. Lidar measurements were useful for in-flight determination of the location and spatial extent of the contrails, and also to report extinction values that agreed well with those calculated from the microphysical data. A shortwave spectrometer was also able to detect the contrails, though the signal was weak due to the dispersion and evaporation of the contrails. Post-flight the UK Met Office NAME III dispersion model was successfully used as a tool for modelling the dispersion of the persistent contrail; determining its location and age, and determining when there was interference from other measured aircraft contrails or when cirrus encroached on the area later in the flight.

The

Lidar investigations on the optical and dynamical properties of cirrus clouds in the upper troposphere and lower stratosphere regions at a tropical station, Gadanki, India (13.5°N, 79.2°E)

Science.gov (United States)

Krishnakumar, Vasudevannair; Satyanarayana, Malladi; Radhakrishnan, Soman R.; Dhaman, Reji K.; Jayeshlal, Glory Selvan; Motty, Gopinathan Nair S.; Pillai, Vellara P. Mahadevan; Raghunath, Karnam; Ratnam, Madineni Venkat; Rao, Duggirala Ramakrishna; Sudhakar, Pindlodi

2014-01-01

High altitude cirrus clouds are composed mainly of ice crystals with a variety of sizes and shapes. They have a large influence on Earth's energy balance and global climate. Recent studies indicate that the formation, dissipation, life time, optical, and micro-physical properties are influenced by the dynamical conditions of the surrounding atmosphere like background aerosol, turbulence, etc. In this work, an attempt has been made to quantify some of these characteristics by using lidar and mesosphere-stratosphere-troposphere (MST) radar. Mie lidar and 53 MHz MST radar measurements made over 41 nights during the period 2009 to 2010 from the tropical station, Gadanki, India (13.5°N, 79.2°E). The optical and microphysical properties along with the structure and dynamics of the cirrus are presented as observed under different atmospheric conditions. The study reveals the manifestation of different forms of cirrus with a preferred altitude of formation in the 13 to 14 km altitude. There are considerable differences in the properties obtained among 2009 and 2010 showing significant anomalous behavior in 2010. The clouds observed during 2010 show relatively high asymmetry and large multiple scattering effects. The anomalies found during 2010 may be attributed to the turbulence noticed in the surrounding atmosphere. The results show a clear correlation between the crystal morphology in the clouds and the dynamical conditions of the prevailing atmosphere during the observational period.

International feedback experience on the cutting of reactor internal components

International Nuclear Information System (INIS)

Boucau, J.

2014-01-01

Westinghouse capitalizes more than 30 years of experience in the cutting of internal components of reactor and their packaging in view of their storage. Westinghouse has developed and validated different methods for cutting: plasma torch cutting, high pressure abrasive water jet cutting, electric discharge cutting and mechanical cutting. A long feedback experience has enabled Westinghouse to list the pros and cons of each cutting technology. The plasma torch cutting is fast but rises dosimetry concerns linked to the control of the cuttings and the clarity of water. Abrasive water jet cutting requires the installation of costly safety devices and of an equipment for filtering water but this technology allows accurate cuttings in hard-to-reach zones. Mechanical cutting is the most favourable technology in terms of wastes generation and of the clarity of water but the cutting speed is low. (A.C.)

Overview of Experiments for Physics of Fast Reactors from the International Handbooks of Evaluated Criticality Safety Benchmark Experiments and Evaluated Reactor Physics Benchmark Experiments

Energy Technology Data Exchange (ETDEWEB)

Bess, J. D.; Briggs, J. B.; Gulliford, J.; Ivanova, T.; Rozhikhin, E. V.; Semenov, M. Yu.; Tsibulya, A. M.; Koscheev, V. N.

2017-07-01

Overview of Experiments to Study the Physics of Fast Reactors Represented in the International Directories of Critical and Reactor Experiments John D. Bess Idaho National Laboratory Jim Gulliford, Tatiana Ivanova Nuclear Energy Agency of the Organisation for Economic Cooperation and Development E.V.Rozhikhin, M.Yu.Sem?nov, A.M.Tsibulya Institute of Physics and Power Engineering The study the physics of fast reactors traditionally used the experiments presented in the manual labor of the Working Group on Evaluation of sections CSEWG (ENDF-202) issued by the Brookhaven National Laboratory in 1974. This handbook presents simplified homogeneous model experiments with relevant experimental data, as amended. The Nuclear Energy Agency of the Organization for Economic Cooperation and Development coordinates the activities of two international projects on the collection, evaluation and documentation of experimental data - the International Project on the assessment of critical experiments (1994) and the International Project on the assessment of reactor experiments (since 2005). The result of the activities of these projects are replenished every year, an international directory of critical (ICSBEP Handbook) and reactor (IRPhEP Handbook) experiments. The handbooks present detailed models of experiments with minimal amendments. Such models are of particular interest in terms of the settlements modern programs. The directories contain a large number of experiments which are suitable for the study of physics of fast reactors. Many of these experiments were performed at specialized critical stands, such as BFS (Russia), ZPR and ZPPR (USA), the ZEBRA (UK) and the experimental reactor JOYO (Japan), FFTF (USA). Other experiments, such as compact metal assembly, is also of interest in terms of the physics of fast reactors, they have been carried out on the universal critical stands in Russian institutes (VNIITF and VNIIEF) and the US (LANL, LLNL, and others.). Also worth mentioning

The North American Career Development Partnership: Experiment in International Collaboration.

Science.gov (United States)

Carslon, Burton L.; Goguen, Robert A.; Jarvis, Phillip S.; Lester, Juliette N.

2000-01-01

Describes how career development programs became the focus of an international partnership between the United States and Canada. Traces the history of each country's efforts, beginning in the 1970s, which led to this significant international collaboration. Concludes with a discussion of the lessons learned from these experiences. (Author/JDM)

Wind and Solar Curtailment: International Experience and Practices

DEFF Research Database (Denmark)

Lew, Debra; Bird, Lori; Milligan, Michael

2013-01-01

High penetrations of wind and solar generation on power systems are resulting in increasing curtailment. Wind and solar integration studies predict increased curtailment as penetration levels grow. This paper examines experiences with curtailment on bulk power systems internationally. It discusses...... how much curtailment is occurring, how it is occurring, why it is occurring, and what is being done to reduce curtailment. This summary is produced as part of the International Energy Agency Wind Task 25 on Design and Operation of Power Systems with Large Amounts of Wind Power....

Parameterizing the competition between homogeneous and heterogeneous freezing in cirrus cloud formation – monodisperse ice nuclei

Directory of Open Access Journals (Sweden)

D. Barahona

2009-01-01

Full Text Available We present a parameterization of cirrus cloud formation that computes the ice crystal number and size distribution under the presence of homogeneous and heterogeneous freezing. The parameterization is very simple to apply and is derived from the analytical solution of the cloud parcel equations, assuming that the ice nuclei population is monodisperse and chemically homogeneous. In addition to the ice distribution, an analytical expression is provided for the limiting ice nuclei number concentration that suppresses ice formation from homogeneous freezing. The parameterization is evaluated against a detailed numerical parcel model, and reproduces numerical simulations over a wide range of conditions with an average error of 6±33%. The parameterization also compares favorably against other formulations that require some form of numerical integration.

Characteristics and experiences of interns in strength and conditioning.

Science.gov (United States)

Read, Paul; Hughes, Jonathan D; Blagrove, Richard; Jeffreys, Ian; Edwards, Mike; Turner, Anthony N

2017-02-01

Student coaches undertake internships to develop practical skills and gain experience to improve employability prospects. The characteristics of the coaches who undertake these internships, their experiences and the nature of the work being performed are currently unknown. The purpose of this study was to report the characteristics of strength and conditioning (S&C) coaches who have undertaken internships and their experiences during their respective placements. A total of 113 men and 6 women completed an online survey. Placements generally lasted 6-12 months (66%), were unpaid (93%) and took place at professional teams (63%). All respondents had a standard of experience prior to commencement (82%); a higher-education degree (bachelor's degree 56%; master's degree 18%) and others were qualified S&C coaches (16%). Activities consisted largely of coaching (47%), data collection (22%) and equipment set-up (25%) but lacked provision of appropriate training. Mentors were allocated to interns; however, often developmental objectives were not discussed, meetings were rarely documented, and in some cases, no meetings took place. This study suggests that internships offer worthwhile experiences and assistance in skill development to progress in S&C. However, clearer guidelines are required to define the responsibilities of employers and interns, to maximise these experiential learning opportunities and avoid the exploitation of willing students.

An Overview of the International Reactor Physics Experiment Evaluation Project

International Nuclear Information System (INIS)

Briggs, J. Blair; Gulliford, Jim

2014-01-01

Interest in high-quality integral benchmark data is increasing as efforts to quantify and reduce calculational uncertainties associated with advanced modeling and simulation accelerate to meet the demands of next generation reactor and advanced fuel cycle concepts. Two Organization for Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA) activities, the International Criticality Safety Benchmark Evaluation Project (ICSBEP), initiated in 1992, and the International Reactor Physics Experiment Evaluation Project (IRPhEP), initiated in 2003, have been identifying existing integral experiment data, evaluating those data, and providing integral benchmark specifications for methods and data validation for nearly two decades. Data provided by those two projects will be of use to the international reactor physics, criticality safety, and nuclear data communities for future decades. An overview of the IRPhEP and a brief update of the ICSBEP are provided in this paper.

Application of a multiple scattering model to estimate optical depth, lidar ratio and ice crystal effective radius of cirrus clouds observed with lidar.

Directory of Open Access Journals (Sweden)

Gouveia Diego

2018-01-01

Full Text Available Lidar measurements of cirrus clouds are highly influenced by multiple scattering (MS. We therefore developed an iterative approach to correct elastic backscatter lidar signals for multiple scattering to obtain best estimates of single-scattering cloud optical depth and lidar ratio as well as of the ice crystal effective radius. The approach is based on the exploration of the effect of MS on the molecular backscatter signal returned from above cloud top.

A Look into International Graduate Students' Experience in the United States: A Grounded Theory Model

Science.gov (United States)

Fujisaki, Shuko

2013-01-01

The number of international students in the United States has been increasing each year, but little is known about their experience. There are recent studies on international students, however, only a few research has focused on international students studying at graduate level. To best study international graduate students' experience, a…

IRPhEP-handbook, International Handbook of Evaluated Reactor Physics Benchmark Experiments

International Nuclear Information System (INIS)

Sartori, Enrico; Blair Briggs, J.

2008-01-01

1 - Description: The purpose of the International Reactor Physics Experiment Evaluation Project (IRPhEP) is to provide an extensively peer-reviewed set of reactor physics-related integral data that can be used by reactor designers and safety analysts to validate the analytical tools used to design next-generation reactors and establish the safety basis for operation of these reactors. This work of the IRPhEP is formally documented in the 'International Handbook of Evaluated Reactor Physics Benchmark Experiments,' a single source of verified and extensively peer-reviewed reactor physics benchmark measurements data. The IRPhE Handbook is available on DVD. You may request a DVD by completing the DVD Request Form available at: http://irphep.inl.gov/handbook/hbrequest.shtml The evaluation process entails the following steps: 1. Identify a comprehensive set of reactor physics experimental measurements data, 2. Evaluate the data and quantify overall uncertainties through various types of sensitivity analysis to the extent possible, verify the data by reviewing original and subsequently revised documentation, and by talking with the experimenters or individuals who are familiar with the experimental facility, 3. Compile the data into a standardized format, 4. Perform calculations of each experiment with standard reactor physics codes where it would add information, 5. Formally document the work into a single source of verified and peer reviewed reactor physics benchmark measurements data. The International Handbook of Evaluated Reactor Physics Benchmark Experiments contains reactor physics benchmark specifications that have been derived from experiments that were performed at various nuclear experimental facilities around the world. The benchmark specifications are intended for use by reactor physics personal to validate calculational techniques. The 2008 Edition of the International Handbook of Evaluated Reactor Physics Experiments contains data from 25 different

A 2-d modeling approach for studying the formation, maintenance, and decay of Tropical Tropopause Layer Cirrus associated with Deep Convection

Science.gov (United States)

Henz, D. R.; Hashino, T.; Tripoli, G. J.; Smith, E. A.

2009-12-01

This study is being conducted to examine the distribution, variability, and formation-decay processes of TTL cirrus associated with tropical deep convection using the University of Wisconsin Non-Hydrostatic modeling system (NMS). The experimental design is based on Tripoli, Hack and Kiehl (1992) which explicitly simulates the radiative-convective equilibrium of the tropical atmosphere over extended periods of weeks or months using a 2D periodic cloud resolving model. The experiment design includes a radiation parameterization to explicitly simulate radiative transfer through simulated crystals. Advanced Microphysics Prediction System (AMP) will be used to simulate microphysics by employing SHIPS (Spectral Habit Ice Prediction System) for ice, SLiPS (Spectral Liquid Prediction System) for droplets, and SAPS (Spectral Aerosol Prediction System) for aerosols. The ice scheme called SHIPS is unique in that ice particle properties (such as size, particle density, and crystal habitats) are explicitly predicted in a CRM (Hashino and Tripoli, 2007, 2008). The Advanced Microphysics Prediction System (AMPS) technology provides a particularly strong tool that effectively enables the explicit modeling of the TTL cloud microphysics and dynamical processes which has yet to be accomplished by more traditional bulk microphysics approaches.

INTERNATIONAL EXPERIENCE OF ADMINISTRATION OF PNEUMOCOCCAL CONJUGATED VACCINES: PROBLEMS, PROGRESS, PERSPECTIVES

Directory of Open Access Journals (Sweden)

M.V. Fedoseenko

2009-01-01

Full Text Available This article presents the review of results of International conference on pneumococcal conjugated vaccines. Main results of international experience in the field of control of pneumococcal infection spreading are analyzed. Authors present modern data of clinical and economic effectiveness and safety of pneumococcal conjugated vaccine RCV-7, and describe experience of administration of vaccines of next generation – PCV-10 and PCV-13.Key words: children, pneumococcal infections, prophylaxis, vaccines.(Voprosy sovremennoi pediatrii — Current Pediatrics. 2009;8(1:130-134

Experiences of Chinese international students learning English at ...

African Journals Online (AJOL)

This article aims to provide insight into the experiences of Chinese international students in some South African tertiary institutions. The study investigates their successes and failures in endeavouring to learn English and the culture shock and 'learning shock' they endure when registering to study in an African country with ...

Voices of Dissent: Unpacking Vietnamese International Student Experience

Science.gov (United States)

Huong, Le; Koo, Fung Kuen; Arambewela, Rodney; Zutshi, Ambika

2017-01-01

Purpose: The purpose of this paper is to examine Vietnamese international students' experiences with the campus learning environment by analysing differences in staff and student perceptions. Design/Methodology/Approach: Two focus groups (n = 12) and ten in-depth interviews were conducted with Vietnamese students and four in-depth interviews with…

FOREIGN EXPERIENCE OF MANAGEMENT AND NORMATIVELY-LEGAL ADJUSTING BY INTERNATIONAL TRANSPORTATIONS

Directory of Open Access Journals (Sweden)

Nataliya Grigorievna Kuftinova

2015-09-01

Full Text Available In this article foreign experience of management is examined by international transportations and prospects of development of management information by bus transportations and transportations of loads. Normatively-legal adjusting, basic norms of domestic law as article of intergovernmental agreements on international transportations.

South Korea's Experience with International Capital Flows

OpenAIRE

Marcus Noland

2005-01-01

South Korea%u2019s experience is unparalleled in its combination of sustained prosperity, capital controls, and financial crisis. Over several decades, South Korea experienced rapid sustained growth in the presence of capital controls. These controls and the de-linking of domestic and international financial markets were an essential component of the country's state-led development strategy. As the country developed, opportunities for easy technological catch-up eroded, requiring more sophist...

International handbook of evaluated criticality safety benchmark experiments

International Nuclear Information System (INIS)

2010-01-01

The Criticality Safety Benchmark Evaluation Project (CSBEP) was initiated in October of 1992 by the United States Department of Energy. The project quickly became an international effort as scientists from other interested countries became involved. The International Criticality Safety Benchmark Evaluation Project (ICSBEP) became an official activity of the Organization for Economic Cooperation and Development - Nuclear Energy Agency (OECD-NEA) in 1995. This handbook contains criticality safety benchmark specifications that have been derived from experiments performed at various nuclear critical facilities around the world. The benchmark specifications are intended for use by criticality safety engineers to validate calculational techniques used to establish minimum subcritical margins for operations with fissile material and to determine criticality alarm requirement and placement. Many of the specifications are also useful for nuclear data testing. Example calculations are presented; however, these calculations do not constitute a validation of the codes or cross section data. The evaluated criticality safety benchmark data are given in nine volumes. These volumes span over 55,000 pages and contain 516 evaluations with benchmark specifications for 4,405 critical, near critical, or subcritical configurations, 24 criticality alarm placement / shielding configurations with multiple dose points for each, and 200 configurations that have been categorized as fundamental physics measurements that are relevant to criticality safety applications. Experiments that are found unacceptable for use as criticality safety benchmark experiments are discussed in these evaluations; however, benchmark specifications are not derived for such experiments (in some cases models are provided in an appendix). Approximately 770 experimental configurations are categorized as unacceptable for use as criticality safety benchmark experiments. Additional evaluations are in progress and will be

The International Student's Experience: An Exploratory Study of Students from Vietnam

Science.gov (United States)

Wearring, Andrew; Le, Huong; Wilson, Rachel; Arambewela, Rodney

2015-01-01

International students are an important part of today's global university sector. This paper explores, through 10 in-depth interviews, the perceptions of Vietnamese international students studying with regard to their experience of teaching and learning in Australia. The findings indicate that Vietnamese students struggle with language,…

The Lived Experiences of International Students Who's Family Remains at Home

Science.gov (United States)

Harvey, Theresa; Robinson, Carolyn; Welch, Anthony

2017-01-01

The significant increase of international students, who leave their family at home, to study abroad, especially in the discipline of nursing, has implications for educational practice. This study's aim was to explore adult international students' experiences of leaving spouse and children--for further education overseas. A descriptive…

IRS Guidelines: Joint IAEA/NEA International Reporting System for Operating Experience

International Nuclear Information System (INIS)

2010-01-01

The International Reporting System for Operating Experience (IRS) is an international system jointly operated by the International Atomic Energy Agency (IAEA) and the OECD Nuclear Energy Agency (OECD/NEA). The fundamental objective of the IRS is to contribute to improving the safety of commercial nuclear power plants which are operated worldwide. This objective can be achieved by providing timely and detailed information on lessons learned from operating and construction experience at the international level. This information could be related to issues and events that are related to safety. The purpose of these guidelines is to describe the system and to give users the necessary background and guidance to enable them to produce IRS reports meeting a high standard of quality while retaining the effectiveness of the system expected by all Member States operating nuclear power plants. As this system is owned by the Member States, the IRS Guidelines have been developed and approved by the IRS National Co-ordinators with the assistance of both Secretariats (IAEA/NEA).

International integral experiments databases in support of nuclear data and code validation

International Nuclear Information System (INIS)

Briggs, J. Blair; Gado, Janos; Hunter, Hamilton; Kodeli, Ivan; Salvatores, Massimo; Sartori, Enrico

2002-01-01

The OECD/NEA Nuclear Science Committee (NSC) has identified the need to establish international databases containing all the important experiments that are available for sharing among the specialists. The NSC has set up or sponsored specific activities to achieve this. The aim is to preserve them in an agreed standard format in computer accessible form, to use them for international activities involving validation of current and new calculational schemes including computer codes and nuclear data libraries, for assessing uncertainties, confidence bounds and safety margins, and to record measurement methods and techniques. The databases so far established or in preparation related to nuclear data validation cover the following areas: SINBAD - A Radiation Shielding Experiments database encompassing reactor shielding, fusion blanket neutronics, and accelerator shielding. ICSBEP - International Criticality Safety Benchmark Experiments Project Handbook, with more than 2500 critical configurations with different combination of materials and spectral indices. IRPhEP - International Reactor Physics Experimental Benchmarks Evaluation Project. The different projects are described in the following including results achieved, work in progress and planned. (author)

Optical remote measurement of ozone in cirrus clouds; Optische Fernmessung von Ozon in Zirruswolken

Energy Technology Data Exchange (ETDEWEB)

Reichardt, J. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Physikalische und Chemische Analytik

1998-12-31

The subject of this thesis is theoretical and experimental investigations into the simultaneous optical remote measurement of atmospheric ozone concentration and particle properties. A lidar system was developed that combines the Raman-lidar and the polarization-lidar with the Raman-DIAL technique. An error analysis is given for ozone measurements in clouds. It turns out that the wavelength dependencies of photon multiple scattering and of the particle extinction coefficient necessitate a correction of the measured ozone concentration. To quantify the cloud influence, model calculations based on particle size distributions of spheres are carried out. The most important experimental result of this thesis is the measured evidence of pronounced minima in the ozone distribution in a humid upper troposphere shortly before and during cirrus observation. Good correlation between ozone-depleted altitude ranges and ice clouds is found. This finding is in contrast to ozone profiles measured in a dry and cloud-free troposphere. (orig.) 151 refs.

Status of international benchmark experiment for effective delayed neutron fraction ({beta}eff)

Energy Technology Data Exchange (ETDEWEB)

Okajima, S.; Sakurai, T.; Mukaiyama, T. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-03-01

To improve the prediction accuracy of the {beta}eff, the program of the international benchmark experiment (Beta Effect Reactor Experiment for a New International Collaborative Evaluation: BERNICE) was planned. This program composed of two parts; BERNICE-MASURCA and BERNICE-FCA. The former one was carried out in the fast critical facility MASURCA of CEA, FRANCE between 1993 and 1994. The latter one started in the FCA, JAERI in 1995 and still is going. In these benchmark experiments, various experimental techniques have been applied for in-pile measurements of the {beta}eff. The accuracy of the measurements was better than 3%. (author)

Differential effects of weight bias experiences and internalization on exercise among women with overweight and obesity.

Science.gov (United States)

Pearl, Rebecca L; Puhl, Rebecca M; Dovidio, John F

2015-12-01

This study investigated the effects of experiences with weight stigma and weight bias internalization on exercise. An online sample of 177 women with overweight and obesity (M(age) = 35.48 years, M(BMI) = 32.81) completed questionnaires assessing exercise behavior, self-efficacy, and motivation; experiences of weight stigmatization; weight bias internalization; and weight-stigmatizing attitudes toward others. Weight stigma experiences positively correlated with exercise behavior, but weight bias internalization was negatively associated with all exercise variables. Weight bias internalization was a partial mediator between weight stigma experiences and exercise behavior. The distinct effects of experiencing versus internalizing weight bias carry implications for clinical practice and public health. © The Author(s) 2014.

International experiences in stormwater fee.

Science.gov (United States)

Tasca, F A; Assunção, L B; Finotti, A R

2017-04-01

Stormwater management (SWM) includes a wide range of services aimed at environmental protection, enhancement of water resources and flood control. Local governments are responsible for managing all these aspects within their jurisdiction, but they often present limitations in generating revenues. Thus, many municipalities have been seeking a dedicated funding source for these programs and practices. This publication provides a brief overview of current legal issues associated with stormwater funding focusing on the most used method: fees. It is a successful mechanism to fund legal obligations of municipalities; however, it must have a significant value to motivate the reduction of runoff. Through literature, we found stormwater fees in Australia, Brazil, Canada, Ecuador, France, Germany, Poland, South Africa and the United States (USA). France had the highest average monthly fee, but this financing experience was suspended in 2014. Brazil has the lowest fee by m², comparable to the US fee. While in Brazil overall SWM represents low priority investments, the USA represents one of the most evolved countries in stormwater funding practices. It was noticed by reviewing the international experience that charging stormwater fees is a successful mechanism to fund the legal obligations and environmental protection.

Nuclear Power Plant Operating Experience from the IAEA/NEA International Reporting System for Operating Experience 2012-2014

International Nuclear Information System (INIS)

2018-03-01

The International Reporting System for Operating Experience (IRS) is an essential element of the international operating experience feedback system for nuclear power plants. Its fundamental objective is to contribute to improving safety of commercial nuclear power plants which are operated worldwide. IRS reports contain information on events of safety significance with important lessons learned which assist in reducing recurrence of events at other plants. This sixth publication, covering the period 2012 - 2014, follows the structure of the previous editions. It highlights important lessons based on a review of the approximately 240 event reports received from the participating countries over this period.

CTBT verification-related technologies for peaceful purposes: the French experiences of international cooperation

International Nuclear Information System (INIS)

Massinon, B.

1999-01-01

The French experience concerning CTBT verification-related technologies for peaceful purposes as well a the international cooperation in this field are presented. Possible objectives and cooperation program needs are cited. French experience in international cooperation is related to seismology and seismic hazards in Bolivia, Madagascar, Nepal and Indonesia and is considered as very constructive, meaning that technical experience is developed, consistent scientific results are obtained, and a considerable yield to the CTBT task is achieved. Large scientific benefits are expected from the CTBTO

Studying abroad: a multiple case study of nursing students' international experiences.

Science.gov (United States)

Green, Barbara F; Johansson, Inez; Rosser, Megan; Tengnah, Cassam; Segrott, Jeremy

2008-11-01

This paper examines the experiences of nursing students undertaking an international placement during their pre-registration education. The study took place in two schools--one in the United Kingdom, and one in Sweden. The move of nursing education into higher education enabled students to participate in international exchange programmes. Previous research demonstrates that students participating in such programmes may gain enhanced cultural awareness and experience personal and professional growth. The study comprised a multiple case study, utilising semi-structured individual and group interviews and documentary analysis. Eighteen students from the UK and 14 from Sweden participated. Participants described an increase in confidence, self-reliance and professional knowledge and skills resulting from their international placement. There was an awareness of how healthcare roles differ between countries and a change in attitudes to others from different backgrounds and cultures. The differences between the two cases were marginal. Whilst there was support from both home and host universities this varied between the international placement providers. The international placements were beneficial; however, there is a need for change in the preparation, support and monitoring of students, greater engagement with the partner institutions, and more effective mentoring of staff.

A Raman lidar at La Reunion (20.8° S, 55.5° E for monitoring water vapour and cirrus distributions in the subtropical upper troposphere: preliminary analyses and description of a future system

Directory of Open Access Journals (Sweden)

C. Hoareau

2012-06-01

Full Text Available A ground-based Rayleigh lidar has provided continuous observations of tropospheric water vapour profiles and cirrus cloud using a preliminary Raman channels setup on an existing Rayleigh lidar above La Reunion over the period 2002–2005. With this instrument, we performed a first measurement campaign of 350 independent water vapour profiles. A statistical study of the distribution of water vapour profiles is presented and some investigations concerning the calibration are discussed. Analysis regarding the cirrus clouds is presented and a classification has been performed showing 3 distinct classes. Based on these results, the characteristics and the design of a future lidar system, to be implemented at the new Reunion Island altitude observatory (2200 m for long-term monitoring, is presented and numerical simulations of system performance have been realised to compare both instruments.

ICSBEP-2007, International Criticality Safety Benchmark Experiment Handbook

International Nuclear Information System (INIS)

Blair Briggs, J.

2007-01-01

1 - Description: The Critically Safety Benchmark Evaluation Project (CSBEP) was initiated in October of 1992 by the United Sates Department of Energy. The project quickly became an international effort as scientist from other interested countries became involved. The International Criticality Safety Benchmark Evaluation Project (ICSBEP) is now an official activity of the Organization of Economic Cooperation and Development - Nuclear Energy Agency (OECD-NEA). This handbook contains criticality safety benchmark specifications that have been derived from experiments that were performed at various nuclear critical facilities around the world. The benchmark specifications are intended for use by criticality safety engineers to validate calculational techniques used to establish minimum subcritical margins for operations with fissile material. The example calculations presented do not constitute a validation of the codes or cross section data. The work of the ICSBEP is documented as an International Handbook of Evaluated Criticality Safety Benchmark Experiments. Currently, the handbook spans over 42,000 pages and contains 464 evaluations representing 4,092 critical, near-critical, or subcritical configurations and 21 criticality alarm placement/shielding configurations with multiple dose points for each and 46 configurations that have been categorized as fundamental physics measurements that are relevant to criticality safety applications. The handbook is intended for use by criticality safety analysts to perform necessary validations of their calculational techniques and is expected to be a valuable tool for decades to come. The ICSBEP Handbook is available on DVD. You may request a DVD by completing the DVD Request Form on the internet. Access to the Handbook on the Internet requires a password. You may request a password by completing the Password Request Form. The Web address is: http://icsbep.inel.gov/handbook.shtml 2 - Method of solution: Experiments that are found

Vibration behavior of PWR reactor internals Model experiments and analysis

International Nuclear Information System (INIS)

Assedo, R.; Dubourg, M.; Livolant, M.; Epstein, A.

1975-01-01

In the late 1971, the CEA and FRAMATOME decided to undertake a comprehensive joint program of studying the vibration behavior of PWR internals of the 900 MWe, 50 cycle, 3 loop reactor series being built by FRAMATOME in France. The PWR reactor internals are submitted to several sources of excitation during normal operation. Two main sources of excitation may effect the internals behavior: the large flow turbulences which could generate various instabilities such as: vortex shedding: the pump pressure fluctuations which could generate acoustic noise in the circuit at frequencies corresponding to shaft speed frequencies or blade passing frequencies, and their respective harmonics. The flow induced vibrations are of complex nature and the approach selected, for this comprehensive program, is semi-empirical and based on both theoretical analysis and experiments on a reduced scale model and full scale internals. The experimental support of this program consists of: the SAFRAN test loop which consists of an hydroelastic similitude of a 1/8 scale model of a PWR; harmonic vibration tests in air performed on full scale reactor internals in the manufacturing shop; the GENNEVILLIERS facilities which is a full flow test facility of primary pump; the measurements carried out during start up on the Tihange reactor. This program will be completed in April 1975. The results of this program, the originality of which consists of studying separately the effects of random excitations and acoustic noises, on the internals behavior, and by establishing a comparison between experiments and analysis, will bring a major contribution for explaining the complex vibration phenomena occurring in a PWR

Commissioning experiment of the polarized internal gas target with deuterium at ANKE/COSY

Energy Technology Data Exchange (ETDEWEB)

Gou, Boxing [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Collaboration: ANKE-Collaboration

2012-07-01

In order to conduct the production experiments with polarized deuterium target and (un)polarized proton beam at ANKE/COSY, a commissioning experiment of the polarized internal target with deuterium is imperative. The commissioning experiment includes the measurements of both the vector (Q{sub y}) and tensor (Q{sub yy}) polarization of the deuterium gas target through the nuclear reactions with large and well known analyzing powers, which can be detected in ANKE. The dependence of the polarizations along the storage cell is also determined. The poster presents the physics case for the experiments with deuterium polarized internal target and the apparatus needed for the commissioning experiment, as well as the procedure of extraction for spin observables.

A numerical simulation of a contrail

Energy Technology Data Exchange (ETDEWEB)

Levkov, L.; Boin, M.; Meinert, D. [GKSS-Forschungszentrum Geesthacht GmbH, Geesthacht (Germany)

1997-12-31

The formation of a contrail from an aircraft flying near the tropopause is simulated using a three-dimensional mesoscale atmospheric model including a very complex scheme of parameterized cloud microphysical processes. The model predicted ice concentrations are in very good agreement with data measured during the International Cirrus Experiment (ICE), 1989. Sensitivity simulations were run to determine humidity forcing on the life time of contrails. (author) 4 refs.

A numerical simulation of a contrail

Energy Technology Data Exchange (ETDEWEB)

Levkov, L; Boin, M; Meinert, D [GKSS-Forschungszentrum Geesthacht GmbH, Geesthacht (Germany)

1998-12-31

The formation of a contrail from an aircraft flying near the tropopause is simulated using a three-dimensional mesoscale atmospheric model including a very complex scheme of parameterized cloud microphysical processes. The model predicted ice concentrations are in very good agreement with data measured during the International Cirrus Experiment (ICE), 1989. Sensitivity simulations were run to determine humidity forcing on the life time of contrails. (author) 4 refs.

Work experiences of internationally trained pharmacists in Great Britain.

Science.gov (United States)

Ziaei, Zainab; Hassell, Karen; Schafheutle, Ellen I

2015-04-01

Internationally trained health professionals are an important part of the domestic workforce, but little is known about the working experiences of internationally trained pharmacists (ITPs) in Great Britain (GB). The purpose of this study is to explore the work experiences of ITPs practising in the community or hospital sector in GB. Twenty-five semi-structured, face-to-face interviews were conducted with a sample of European Economic Area (EEA) and non-EEA pharmacists who, at the time of the study, practised in the community (n = 20) or hospital sector (n = 5) in the North West England from March to May 2009. In general, ITPs complained about their heavy workload, long working hours and lack of support from their employers. Specifically, EEA pharmacists in most cases felt excluded from the professional network and sensed colleagues saw them as 'foreigners' while some non-EEA pharmacists had to deal with a level of hostility from patients. This novel research provides a foundation for future work on ITPs in GB and could assist employers to better target their efforts in development of standards to support the working experiences of ITPs in GB. © 2014 Royal Pharmaceutical Society.

Acculturative Stress and Adjustment Experiences of Greek International Students

Science.gov (United States)

Poulakis, Mixalis; Dike, Craig A.; Massa, Amber C.

2017-01-01

This study investigated eight Greek international college students' experiences of acculturation and acculturative stress at a mid-western university in the United States. Semi-structured interviews were conducted with participants and Consensual Qualitative Research methodology was utilized for data analysis to identify contextual themes and…

International Field Experiences Promote Professional Development for Sustainability Leaders

Science.gov (United States)

Hull, R. Bruce; Kimmel, Courtney; Robertson, David P.; Mortimer, Michael

2016-01-01

Purpose: This paper aims to describe, explain and evaluate a graduate education program that provides international project experiences and builds competencies related to collaborative problem-solving, cultural capacity to work globally and sustainable development. Design/methodology/approach: Qualitative analysis of survey data from 28 students…

Educational Activity: A Preliminary Review and Some International Experiences

Directory of Open Access Journals (Sweden)

Salem Ali Al Qahtani

2017-11-01

Full Text Available This paper reviews the history of the educational activity which was entered through John Dewey’s Experimental School, founded in 1896, the first school to use the activity curriculum. It sheds the light on the stages that activity has gone through till today. The Islamic view and a number of quotes from a number of Islamic thinkers and educators also were reviewed. The importance of the activity, its basics, functions, types and classifications were also discussed. The research concluded with a number of international experiences which gave great importance to the activity in their curricula and educational plans. The most important recommendations are: 1 Offering advanced training programs for teachers on educational activity; 2 Adding educational activity as an independent material in educational colleges; 3 Expanding the scope of study for international experiences in educational activity; and 4 Making use of technology and employing it in the educational activity.

Loads Providing Ancillary Services: Review of International Experience

Energy Technology Data Exchange (ETDEWEB)

Heffner, Grayson; Goldman, Charles; Kintner-Meyer, Michael

2007-05-01

In this study, we examine the arrangements for and experiences of end-use loads providing ancillary services (AS) in five electricity markets: Australia, the United Kingdom (UK), the Nordic market, and the ERCOT and PJM markets in the United States. Our objective in undertaking this review of international experience was to identify specific approaches or market designs that have enabled customer loads to effectively deliver various ancillary services (AS) products. We hope that this report will contribute to the ongoing discussion in the U.S. and elsewhere regarding what institutional and technical developments are needed to ensure that customer loads can meaningfully participate in all wholesale electricity markets.

International experience in the use of leasing relations in Ukraine

Directory of Open Access Journals (Sweden)

L.V. Mikhalchuk

2015-09-01

Full Text Available The article examines the market of leasing relations in the UK, Germany, France, the USA. Comparative analysis of development of leasing in foreign countries has been carried out in order to use international experience of leasing relations in Ukraine at the present stage of development of state economy. In spite of prevalence of leasing in developed countries, this kind of relationship is still uncommon in the economic environment of Ukraine because of its novelty and lack of experience. Relevance of leasing development in Ukraine, including the formation of leasing market, primarily is caused by a significant proportion of obsolete equipment and low efficiency of its use. One of solutions to these problems can be leasing which brings together all the elements of international trade, credit, and investment operations.

The importance of international experience for Romanian students in establishing career priorities

Directory of Open Access Journals (Sweden)

Butum Lavinia

2017-03-01

Full Text Available Romanian students′ appreciation towards international experience has been increasing as the number of students involved in international programs has been rising year by year. Also, students′ expectations upon graduation are more related to finding a good job, usually in multinationals. Studies conducted in Romania (Frunzaru et al., 2013 and (Nicolescu and Păun, 2009 showed that students give great attention to the skills they acquire after completing various programs, often their choices being focused on several successful areas and international programs. The joint projects of several universities and governmental authorities in Romania have aimed to develop the international dimension of education (IEMU, 2015. The results of implementing those projects could be revealed by students’ perception of international competences gained by curricula or international exchange programs. The purpose of this paper is to analyze the dynamics of Romanian and European graduates’ satisfaction with international experience and extracurricular resources accessed during university courses. Also, the article will analyze the dynamics of graduates′ career priorities in accordance with the skills provided upon graduation. The data are selected from Trendence Graduate Barometer - Romanian Edition and the analysis establishes relevant conclusions regarding the young Romanian graduates′ need to develop, in comparison with European graduates from 5-year statistic data (2012-2016. The conclusions include a comparison of international exchange programs and career priorities expectations among Romanian and other European graduates. Also, the paper will draw new research directions regarding students′ need for specialization especially in gaining international competences.

Interocular symmetry of retinal nerve fiber layer and optic nerve head parameters measured by Cirrus high-definition optical coherence tomography in a normal pediatric population.

Science.gov (United States)

Pawar, Neelam; Maheshwari, Devendra; Ravindran, Meenakshi; Ramakrishnan, Renagappa

2017-10-01

To determine interocular differences in the retinal nerve fiber layer (RNFL) and optic nerve head (ONH) parameters in a pediatric population using Cirrus high-definition optical coherence tomography (HD-OCT). Seventy normal Indian children aged 5-17 years presenting to the Pediatric Clinic were included in this observational cross-sectional study. All subjects underwent a comprehensive ophthalmologic examination and an evaluation of the RNFL and ONH by Cirrus HD-OCT. Differences between the right and left eyes were calculated and values were compared by means of a paired t-test. Subjects were also divided into two groups based on age (under or over 10 years of age). Interocular differences in RNFL and ONH parameters together with sex and age variations for these differences were determined. The mean age of studied pediatric population was 11.83 ± 3.3 years (range 5-17). Average RNFL thickness was 94.46 ± 8.7 μm (± SD) (range 77-111). Differences in the average RNFL between right and left eyes were not statistically significant (P = 0.060). Superior quadrant RNFL was thicker in the left eye and temporal quadrant was thicker in the right eye. Among ONH parameters, there were no statistically significant differences in any parameters, except vertical cup-disc (CD) ratio which was significant (P = 0.007). The 2.5%-97.5% limits of asymmetry were 9 μm for average RNFL, 0.14 for average CD ratio, and 0.22 for vertical CD ratio. Mean interocular RNFL thickness differences in superior, superior nasal, and temporal superior quadrants were 10.61 (P sex, while only significant differences with age were observed in 12 clock hour sector analysis, mainly in nasal inferior and inferior quadrant. We report the degree of interocular symmetry of RNFL and ONH parameters measured by Cirrus HD-OCT in a healthy pediatric population. The normal interocular RNFL asymmetry should not exceed 9 μm and vertical CD ratio beyond 0.22 should be considered for further investigations. The

GROWTH OF THE INTERNATIONAL CRITICALITY SAFETY AND REACTOR PHYSICS EXPERIMENT EVALUATION PROJECTS

Energy Technology Data Exchange (ETDEWEB)

J. Blair Briggs; John D. Bess; Jim Gulliford

2011-09-01

Since the International Conference on Nuclear Criticality Safety (ICNC) 2007, the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Experiment Evaluation Project (IRPhEP) have continued to expand their efforts and broaden their scope. Eighteen countries participated on the ICSBEP in 2007. Now, there are 20, with recent contributions from Sweden and Argentina. The IRPhEP has also expanded from eight contributing countries in 2007 to 16 in 2011. Since ICNC 2007, the contents of the 'International Handbook of Evaluated Criticality Safety Benchmark Experiments1' have increased from 442 evaluations (38000 pages), containing benchmark specifications for 3955 critical or subcritical configurations to 516 evaluations (nearly 55000 pages), containing benchmark specifications for 4405 critical or subcritical configurations in the 2010 Edition of the ICSBEP Handbook. The contents of the Handbook have also increased from 21 to 24 criticality-alarm-placement/shielding configurations with multiple dose points for each, and from 20 to 200 configurations categorized as fundamental physics measurements relevant to criticality safety applications. Approximately 25 new evaluations and 150 additional configurations are expected to be added to the 2011 edition of the Handbook. Since ICNC 2007, the contents of the 'International Handbook of Evaluated Reactor Physics Benchmark Experiments2' have increased from 16 different experimental series that were performed at 12 different reactor facilities to 53 experimental series that were performed at 30 different reactor facilities in the 2011 edition of the Handbook. Considerable effort has also been made to improve the functionality of the searchable database, DICE (Database for the International Criticality Benchmark Evaluation Project) and verify the accuracy of the data contained therein. DICE will be discussed in separate papers at ICNC 2011. The status of the

Intern as Patient: A Patient Experience Simulation to Cultivate Empathy in Emergency Medicine Residents

Directory of Open Access Journals (Sweden)

Sara W. Nelson

2017-12-01

Full Text Available Introduction Prior work links empathy and positive physician-patient relationships to improved healthcare outcomes. The objective of this study was to analyze a patient experience simulation for emergency medicine (EM interns as a way to teach empathy and conscientious patient care. Methods We conducted a qualitative descriptive study on an in situ, patient experience simulation held during EM residency orientation. Half the interns were patients brought into the emergency department (ED by ambulance and half were family members. Interns then took part in focus groups that discussed the experience. Data collected during these focus groups were coded by two investigators using a grounded theory approach and constant comparative methodology. Results We identified 10 major themes and 28 subthemes in the resulting qualitative data. Themes were in three broad categories: the experience as a patient or family member in the ED; application to current clinical practice; and evaluation of the exercise itself. Interns experienced firsthand the physical discomfort, emotional stress and confusion patients and families endure during the ED care process. They reflected on lessons learned, including the importance of good communication skills, frequent updates on care and timing, and being responsive to the needs and concerns of patients and families. All interns felt this was a valuable orientation experience. Conclusion Conducting a patient experience simulation may be a practical and effective way to develop empathy in EM resident physicians. Additional research evaluating the effect of participation in the simulation over a longer time period and assessing the effects on residents’ actual clinical care is warranted.

The Experiences of American International Students in a Large Irish University

Science.gov (United States)

O'Reilly, Aileen; Hickey, Tina; Ryan, Dermot

2015-01-01

Growing numbers of American students are travelling overseas to study abroad and enroll in full degree programs. Despite this trend, relatively little is known about the experiences of United States (U.S.) students abroad. The aim of this research was to examine the experiences of American international students in Ireland. Findings suggest that…

Internationalization of Canadian Higher Education: Discrepancies between Policies and International Student Experiences

Science.gov (United States)

Guo, Yan; Guo, Shibao

2017-01-01

The internationalization of higher education in Canada is happening at a rapid pace. One manifestation of internationalization is the increasing enrolment of international students in Canadian institutions. There is little research on international undergraduate students' experiences from their own perspectives as they adapt to a new educational…

Measurement of Optic Disc Cup Surface Depth Using Cirrus HD-OCT.

Science.gov (United States)

Kim, Young Kook; Ha, Ahnul; Lee, Won June; Jeoung, Jin Wook; Park, Ki Ho

2017-12-01

To introduce the measurement method of optic disc cup surface depth using spectral-domain optical coherence tomography (SD-OCT) and then evaluate the rates of cup surface depression at 3 different stages of glaucoma. We retrospectively identified 52 eyes with preperimetric glaucoma, 56 with mild-or-moderate glaucoma and 50 with severe glaucoma and followed them for at least 48 months. Eyes were imaged using SD-OCT (Cirrus HD-OCT) at 12-month intervals. The mean cup surface depth was calculated using the following formula: Cup volume/(disc area×average cup-to-disc ratio)-200 μm. The rates of mean cup surface depression (μm/y) were significantly greater in mild-or-moderate glaucoma (-7.96±1.03) than in preperimetric (-3.11±0.61) and severe glaucoma (-0.70±0.12; all Pcup surface depression (%/y) were significantly greater than those of average of retinal nerve fiber layer (RNFL) thinning (%/y) in preperimetric glaucoma (-1.64±0.12 vs. -1.11±0.07; Pcup surface depth changed slower than did average RNFL thickness (-0.64±0.06 vs. -0.75±0.08%/y; Pcup surface depth changed faster than did the RNFL thickness. These results signify the possibility that SD-OCT-based estimation of cup surface depth might be useful for monitoring of glaucoma development and progression.

Experience of International Education of East Asian Students in English-speaking Countries: A four-dimensional approach

Directory of Open Access Journals (Sweden)

Maria L Martinez

2017-07-01

Full Text Available Global participation in international education in the last two decades has increased exponentially. International students face difficulties in adjusting to the culture of their host country due to their unique needs (Bertram, Poulakis, Elsasser & Kumar, 2014. This article presents themes comprising the international education phenomenon involving the experiences of East Asian international students in English-speaking countries. The literature reviewed for this article pertains to many aspects of international education, covering the factors that influence the decision to embark on the international education journey to the adjustment experienced by students to the host culture. The authors suggest that the international education experience is comprised of four dimensions: structural, linguistic, internal, and external. We also posit that Confucianism, which many East Asian students follow, influences not only the psycho-social dimension of the international education experience but also their instructional preferences within the structural dimension. We further contend that students’ actual and perceived proficiency (or the lack thereof in the host country’s language greatly shapes all aspects of the student’s international education experience, which then determines the degree of acculturative stress involved and plays a key role in each of the three dimensions. Because of the anticipated continued growth in the number of international students from East Asia attending higher education institutions in English-speaking countries such as the United States, Australia, Canada, and parts of Africa, it is important to examine how each of the dimensions proposed impact each other. Approaching the study of the international education experience one dimension at a time, as many scholars have done, does not completely address all of the unique needs of international students. We suggest that research in this area be conducted holistically by

Perspectives of Turkish Intern and Non-Intern Students towards Sport Management Internship within the Context of Field Experience

Science.gov (United States)

Coknaz, Dilsad

2014-01-01

The purpose of this study was to examine differences between intern and non-intern students in terms of their perspectives on sport management internship within the context of field experience. The subjects of the study were a total of 189 students. They were 4th year students who completed their internship and 3rd year students who were yet to…

The International Experience in Public Procurement

Directory of Open Access Journals (Sweden)

Pysmenna Mariia S.

2017-11-01

Full Text Available The article is aimed at generalizing the foreign experience of implementing public procurement, analyzing peculiarities of organizational, normative and procedural provision of public procurement in the Member States of the European Union. The relevance of the research topic is due to the need to harmonize the procurement policy of the Government of Ukraine with the international legal framework and with broad political objectives within the European integration strategy. The organizational framework and principles of implementing public procurement in the EU Member States were analyzed. Special attention was paid to normative provision of public procurement by the EU Member States; peculiarities of the use of national or harmonized rules of public procurement in accordance with the amount of the procurement contract; restrictions and conditions for public authorities in the selection of applicants for bidding. Five types of public procurement procedures used in the EU have been characterized, namely: open procedure, limited procedure, negotiation procedure, competitive dialog, electronic auctions. The need to address the social and legal aspects of public procurement in international practice has been substantiated and the possibilities for resolving these problems have been presented.

Tourism and international business: The theoretical approach and practical experiences

Directory of Open Access Journals (Sweden)

Jovičić Dobrica

2011-01-01

Full Text Available The paper discusses the relationships between tourism and international business. The research is based upon combining various theoretical concepts, significant empirical experiences and own attitudes of the authors. The key conclusion of the paper is that, despite of the partial progress in understanding tourism businesses, the relationships between tourism and international business need additional stimulus. In other words, more complete research in the related domains is needed in future. Any understanding of tourism is inadequate without appreciating the contributions that international business might bring, yet at the same time international business is incomplete in its coverage of international trade unless tourism is considered. The consumption-driven agenda of much tourism research has been favoured over supply-side discourses of the production process it self. That is why the role of major transnational companies, setting the trends that other types of firms in the tourism sector follow is focused in the paper.

British Isles Field Experience: An Initiative in International Education.

Science.gov (United States)

Martin, William J.

The British Isles Field Experience (BIFE) program was initiated at Williamsport Area Community College (WACC) to provide a group of WACC faculty and staff members with individual and group activities of a personal, professional, and cultural nature in order to promote an international perspective that can be infused into student, collegiate, and…

Status report on the International Germanium Experiment

International Nuclear Information System (INIS)

Brodzinski, R.L.; Hensley, W.K.; Miley, H.S.; Reeves, J.H.; Avignone, F.T.; Collar, J.I.; Guerard, C.K.; Courant, H.; Ruddick, K.; Kirpichnikov, I.V.; Starostin, A.S.; Osetrov, S.B.; Pomansky, A.A.; Smolnikov, A.A.; Vasiliev, S.I.

1992-06-01

Phase II detector fabrication for the International Germanium Experiment is awaiting resolution of technical details observed during Phase I. Measurements of fiducial volume, configuration of the tansistor-reset preamplifier stage, and sources of background are discussed. Cosmogenic 7 Be is measured in germanium. Radium contamination in electroformed copper reported. The 2ν double- beta decay half-life of 76 Ge measured with a Phase I detector is in reasonable agreement with previously reported values. No events are observed in the vicinity of the Oν double-beta decay energy

Short-Term International Experience (STIE) and Students' Understanding of Quality Early Childhood Service Provision

Science.gov (United States)

Sims, Margaret; Nishida, Yukiyo

2018-01-01

Exposing pre-service teachers to international professional experiences through a short-term visiting programme serves to challenge their understandings of good quality practice through disturbing assumptions and expectations previously formed through experiences in their own country/culture. Much of the research in international study focuses on…

Digital Journeys: A Perspective on Understanding the Digital Experiences of International Students

Science.gov (United States)

Chang, Shanton; Gomes, Catherine

2017-01-01

The authors in this conceptual paper draw on the literature on information seeking behavior, social media use, and international student experiences to propose Digital Journeys as a framework which helps us understand the online behavior of international students. Here we theorize that the Digital Journey is the transition that individuals make…

International academic mobility in nursing education: an experience report.

Science.gov (United States)

Guskuma, Erica Mayumi; Dullius, Aline Alves Dos Santos; Godinho, Mônica La Salette da Costa; Costa, Maria Silvana Totti; Terra, Fábio de Souza

2016-01-01

report the experience of international academic mobility in Ireland through the program Science Without Borders during undergraduate education in nursing. a report of experience presented in chronological order, with a descriptive nature. the opportunity to know and be able to discuss questions regarding health and nursing in Ireland allowed the review of concepts and a more reflective perspective regarding nursing practices. Additionally, the exchange promoted personal strengthening regarding the confrontation and solution of problems, development of technical and scientific abilities, improvement of linguistic competences and construction of personality, independence and maturity. regarding such constructive and enriching experience that this mobility provides to students, to the governing authorities, to the population and to Brazilian nursing, sharing this experience is expected to serve as encouragement for those who search for new horizons, with the objective of adding knowledge for their personal and professional life.

STATUS OF THE INTERNATIONAL MUON IONIZATION COOLING EXPERIMENT(MICE)

International Nuclear Information System (INIS)

Zisman, Michael S.

2007-01-01

An international experiment to demonstrate muon ionization cooling is scheduled for beam at Rutherford Appleton Laboratory (RAL) in 2007. The experiment comprises one cell of the Study II cooling channel [1], along with upstream and downstream detectors to identify individual muons and measure their initial and final 6D phase-space parameters to a precision of 0.1%. Magnetic design of the beam line and cooling channel are complete and portions are under construction. The experiment will be described, including cooling channel hardware designs, fabrication status, and running plans. Phase 1 of the experiment will prepare the beam line and provide detector systems, including time-of-flight, Cherenkov, scintillating-fiber trackers and their spectrometer solenoids, and an electromagnetic calorimeter. The Phase 2 system will add the cooling channel components, including liquid-hydrogen absorbers embedded in superconducting Focus Coil solenoids, 201-MHz normal-conducting RF cavities, and their surrounding Coupling Coil solenoids. The MICE Collaboration goal is to complete the experiment by 2010; progress toward this is discussed

IRPhE - International Reactor Physics Experiments database

International Nuclear Information System (INIS)

Sartori, E.

2004-01-01

The OECD/NEA Nuclear Science Committee (NSC) has identified the need to establish international databases containing all the important experiments that are available for sharing among the specialists and has set up or sponsored specific activities to achieve this. The aim is to preserve them in an agreed standard format in computer accessible form, to use them for international activities involving validation of current and new calculational schemes including computer codes and nuclear data libraries, for assessing uncertainties, confidence bounds and safety margins, and to record measurement methods and techniques. It is a significant saving results from disseminating a standard benchmark set to be used worldwide. A framework for professionals that use the standard benchmark set to validate and verify modeling codes and data for radiation transport, criticality safety and reactor physics applications guarantees a comparative set of analyses. It represents also a good basis for pinpointing important gaps and where efforts should be concentrated and ensures knowledge and competence preservation, management and transfer in nuclear science and engineering. A large number of experimentalists, physicists, evaluators, modelers have devoted large amounts of their efforts and competencies to produce the data on which the methods we are using today are based. These data are far from having been exploited fully for the different nuclear and radiation technologies. This wealth of information needs to be preserved in a form more easily exploitable by modern information technology and for use in connection with novel and refined computational models with limitations of the past removed. These data will form the basis for the studies of more advanced nuclear technology, will be instrumental in identifying areas where there is a lack of knowledge and thus provide support to justifying new experiments that would reduce design uncertainties and consequently costs. Improvement of

Internal interface for RFC muon trigger electronics at CMS experiment

CERN Document Server

Pozniak, Krzysztof T; Pietrusinski, Michall

2004-01-01

The paper describes design and practical realization of an internal communication layer referred to as the Internal Interface (II). The system was realized for the RFC Muon Trigger of the CMS experiment. Fully automatic implementation of the communication layer is realized in the FPGA chips and in the control software. The methodology of implementation was presented in the description form of the interface structure from the sides of hardware and software. The examples of the communication layer realizations were given for the RFC Muon Trigger.

International experience in conditioning spent fuel elements

International Nuclear Information System (INIS)

Ashton, P.

1991-04-01

The purpose of this report is to compile and present in a clear form international experience (USA, Canada, Sweden, FRG, UK, Japan, Switzerland) gained to date in conditioning spent fuel elements. The term conditioning is here taken to mean the handling and packaging of spent fuel elements for short- or long-term storage or final disposal. Plants of a varying nature fall within this scope, both in terms of the type of fuel element treated and the plant purpose eg. experimental or production plant. Emphasis is given to plants which bear some similarity to the concept developed in Germany for direct disposal of spent fuel elements. Worldwide, however, relatively few conditioning plants are in existence or have been conceived. Hence additional plants have been included where aspects of the experience gained are also of relevance eg. plants developed for the consolidation of spent fuel elements. (orig./HP) [de

Experience with nuclear safety standards development in non-governmental international organizations

International Nuclear Information System (INIS)

Becker, K.

1985-01-01

Besides the IAEA as a 'governmental' organization dealing with basic safety recommendations addressed primarily to the national regulatory bodies in developing countries, two closely related non-governmental international standards organizations have gained extensive experience in the field of nuclear standardization. Over more than 25 years since their formation, both (a) the International Organization for Standardization's (ISO) Technical Committee 85 'Nuclear Energy', in particular in its Sub-Committee 3 'Reactor Technology and Safety' and (b) the International Electrotechnical Commission's (IEC) Technical Committee 45 'Nuclear Instrumentation' have published numerous standards. A brief review is given of these, draft standards, and other documents planned to become international standards. Many of them deal with rather specialized topics typical for 'industrial' standards such as standardized procedures, instruments, methods, materials, test methods, terminology, and signs and symbols, but others are directly related to more basic safety issues. In some areas such as quality assurance, seismic aspects of siting and terminology, there has been in the past occasional overlap in the activities of the NUSS programme, IEC and ISO. Letters of Understanding have since 1981 contributed to clarifying the borderlines and to avoiding redundant efforts. Also, some experiences and problems are described arising, for example, from the harmonization of different national safety philosophies and traditions into universally accepted international standards, and the transfer of international standards into national standards systems. Finally, based on a recent comprehensive compilation of some 3300 nuclear standards and standards projects, an attempt is made to present a cost/benefit analysis and an outlook on future developments. (author)

Language proficiency and the international postgraduate student experience

OpenAIRE

Weaver, M

2016-01-01

In an increasingly competitive environment, with reduced government funding, full fee-paying international students are an important source of revenue for higher education institutions (HEIs). Although many previous studies have focused on the role of English language proficiency on academic success, there is little known about the extent to which levels of English language proficiency affect these non-native English speaking students’ overall course experience. There have been a wealth of st...

The Voluntariat: A Freirean framework to understand the nature of undergraduate international (medical) experiences

OpenAIRE

Seemi Qaiser; Helen Dimaras; Paul Hamel

2016-01-01

Despite literature documenting limited and asymmetrical benefits along with ethical issues, short-term international volunteering is increasingly popular among North American university students as a perceived advantage when applying to professional healthcare schools or the job market. Academic institutions are also encouraging students to pursue international experiences in order to cultivate values as global citizens. These experiences are most typically limited to economically privileged ...

The Voluntariat: A Frieirean framework to understand the nature of undergraduate international (medical) experiences

OpenAIRE

Qaiser, Seemi; Dimaras, Helen; Hamel, Paul

2016-01-01

Despite literature documenting limited and asymmetrical benefits along with ethical issues, short-term international volunteering is increasingly popular among North American university students as a perceived advantage when applying to professional healthcare schools or the job market. Academic institutions are also encouraging students to pursue international experiences in order to cultivate values as global citizens. These experiences are most typically limited to economically privileged ...

International Practica Experiences as Events of Influence in a Teacher Candidates' Development

Science.gov (United States)

Maynes, Nancy; Allison, John; Julien-Schultz, Lynn

2012-01-01

Experience may influence beliefs and beliefs may influence practices. Following these premises, we investigated teacher candidates' post experience reflections nine months after an international practicum where they taught for three weeks in rural Kenya. Teacher candidates were placed in non-governmental organization (NGO) sponsored schools on the…

Technology Experiences of Student Interns in a One to One Mobile Program

Science.gov (United States)

Cullen, Theresa A.; Karademir, Tugra

2018-01-01

This article describes how a group of student intern teachers (n = 51) in a one to one teacher education iPad program were asked to reflect using Experience Sampling Method (ESM) on their use of technology in the classroom during internship. Interns also completed summative reflections and class discussions. Data collected both in online and…

Temperature profiles from MBT casts from the CIRRUS and CUMULUS from Ocean Weather Station K (OWS-K) and M (OWS-M) in the North Atlantic Ocean from 1969-01-01 to 1970-01-16 (NODC Accession 7000939)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bathythermograph data were collected from the CIRRUS and CUMULUS within a 1-mile radius of Ocean Weather Station K (4500N 01600W), M (6600N 00200E), and in transit....

Temperature profiles from MBT casts from the CIRRUS and other platforms from multiple Ocean Weather Station (OWS) in the North Atlantic Ocean and North Pacific Ocean from 1967-12-06 to 1970-10-04 (NODC Accession 7101080)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bathythermograph data were collected from the CIRRUS and other platforms within a 1-mile radius of Ocean Weather Station A (6200N 03300W), B (5630N 05100W), C (5245N...

Student Conceptions of International Experience in the Study Abroad Context

Science.gov (United States)

Streitwieser, Bernhard T.; Light, Gregory J.

2018-01-01

While much of recent study abroad research has focused on identifying and measuring different learning outcomes in terms of specific skills, competencies, perspectives and attributes acquired during study abroad opportunities, less research has considered how students' deeper conceptions and understandings of international experience may change…

Numerical simulations of contrail-to-cirrus transition – Part 2: Impact of initial ice crystal number, radiation, stratification, secondary nucleation and layer depth

Directory of Open Access Journals (Sweden)

S. Unterstrasser

2010-02-01

Full Text Available Simulations of contrail-to-cirrus transition were performed with an LES model. In Part 1 the impact of relative humidity, temperature and vertical wind shear was explored in a detailed parametric study. Here, we study atmospheric parameters like stratification and depth of the supersaturated layer and processes which may affect the contrail evolution. We consider contrails in various radiation scenarios herein defined by the season, time of day and the presence of lower-level cloudiness which controls the radiance incident on the contrail layer. Under suitable conditions, controlled by the radiation scenario and stratification, radiative heating lifts the contrail-cirrus and prolongs its lifetime. The potential of contrail-driven secondary nucleation is investigated. We consider homogeneous nucleation and heterogeneous nucleation of preactivated soot cores released from sublimated contrail ice crystals. In our model the contrail dynamics triggered by radiative heating does not suffice to force homogeneous freezing of ambient liquid aerosol particles. Furthermore, our model results suggest that heterogeneous nucleation of preactivated soot cores is unimportant. Contrail evolution is not controlled by the depth of the supersaturated layer as long as it exceeds roughly 500 m. Deep fallstreaks however need thicker layers. A variation of the initial ice crystal number is effective during the whole evolution of a contrail. A cut of the soot particle emission by two orders of magnitude can reduce the contrail timescale by one hour and the optical thickness by a factor of 5. Hence future engines with lower soot particle emissions could potentially lead to a reduction of the climate impact of aviation.

Experiences of internationally educated nurses holding management positions in the United States: Descriptive phenomenological study.

Science.gov (United States)

Allen, Lilian A

2018-02-12

The purpose of this study was to explore the experiences of internationally educated nurses in management positions in United States health care organisations to understand the obstacles and support these individuals' experience when pursuing and working in managerial roles. Although internationally educated nurses are an integral part of the US health care industry, few work in managerial roles. Little is known about the experiences of internationally educated nurses who do obtain management positions. In this qualitative, phenomenological study, seven internationally educated nurses who were managers in Chicago, Illinois, responded to open-ended interview questions. Supervisors contributed to the participants' acceptance of management positions. The participants experienced challenges such as cultural differences, language, and communication. Despite these challenges, the participants had positive working relationships with staff and supervisors. Further, the participants had opportunities for education and professional growth. Internationally educated nurses benefit from participating in organisational committees. They face challenges related to work responsibilities, cultural differences and communication but can succeed in management roles through developing strategies to overcome the challenges and through receiving support from staff, colleagues and supervisors. More internationally educated nurses may obtain managerial positions if supervisors provide encouragement and support. © 2018 John Wiley & Sons Ltd.

International Reactor Physics Experiment Evaluation (IRPhE) Project. IRPhE Handbook - 2015 edition

International Nuclear Information System (INIS)

Bess, John D.; Gullifor, Jim

2015-03-01

The purpose of the International Reactor Physics Experiment Evaluation (IRPhE) Project is to provide an extensively peer-reviewed set of reactor physics-related integral data that can be used by reactor designers and safety analysts to validate the analytical tools used to design next-generation reactors and establish the safety basis for operation of these reactors. This work of the IRPhE Project is formally documented in the 'International Handbook of Evaluated Reactor Physics Benchmark Experiments', a single source of verified and extensively peer-reviewed reactor physics benchmark measurements data. The evaluation process entails the following steps: Identify a comprehensive set of reactor physics experimental measurements data, Evaluate the data and quantify overall uncertainties through various types of sensitivity analysis to the extent possible, verify the data by reviewing original and subsequently revised documentation, and by talking with the experimenters or individuals who are familiar with the experimental facility, Compile the data into a standardized format, Perform calculations of each experiment with standard reactor physics codes where it would add information, Formally document the work into a single source of verified and peer reviewed reactor physics benchmark measurements data. The International Handbook of Evaluated Reactor Physics Benchmark Experiments contains reactor physics benchmark specifications that have been derived from experiments that were performed at nuclear facilities around the world. The benchmark specifications are intended for use by reactor designers, safety analysts and nuclear data evaluators to validate calculation techniques and data. Example calculations are presented; these do not constitute a validation or endorsement of the codes or cross-section data. The 2015 edition of the International Handbook of Evaluated Reactor Physics Benchmark Experiments contains data from 143 experimental series that were

A Burning Plasma Experiment: the role of international collaboration

Science.gov (United States)

Prager, Stewart

2003-04-01

The world effort to develop fusion energy is at the threshold of a new stage in its research: the investigation of burning plasmas. A burning plasma is self-heated. The 100 million degree temperature of the plasma is maintained by the heat generated by the fusion reactions themselves, as occurs in burning stars. The fusion-generated alpha particles produce new physical phenomena that are strongly coupled together as a nonlinear complex system, posing a major plasma physics challenge. Two attractive options are being considered by the US fusion community as burning plasma facilities: the international ITER experiment and the US-based FIRE experiment. ITER (the International Thermonuclear Experimental Reactor) is a large, power-plant scale facility. It was conceived and designed by a partnership of the European Union, Japan, the Soviet Union, and the United States. At the completion of the first engineering design in 1998, the US discontinued its participation. FIRE (the Fusion Ignition Research Experiment) is a smaller, domestic facility that is at an advanced pre-conceptual design stage. Each facility has different scientific, programmatic and political implications. Selecting the optimal path for burning plasma science is itself a challenge. Recently, the Fusion Energy Sciences Advisory Committee recommended a dual path strategy in which the US seek to rejoin ITER, but be prepared to move forward with FIRE if the ITER negotiations do not reach fruition by July, 2004. Either the ITER or FIRE experiment would reveal the behavior of burning plasmas, generate large amounts of fusion power, and be a huge step in establishing the potential of fusion energy to contribute to the world's energy security.

Status of the International Muon Ionization Cooling Experiment (MICE)

International Nuclear Information System (INIS)

Zisman, Michael S.; Zisman, Michael S.

2007-01-01

An international experiment to demonstrate muon ionization cooling is scheduled for beam at Rutherford Appleton Laboratory (RAL) in 2007. The experiment comprises one cell of the Study II cooling channel [1], along with upstream and downstream detectors to identify individual muons and measure their initial and final 6D phase-space parameters to a precision of 0.1 percent. Magnetic design of the beam line and cooling channel are complete and portions are under construction. The experiment will be described, including cooling channel hardware designs, fabrication status, and running plans. Phase 1 of the experiment will prepare the beam line and provide detector systems, including time-of-flight, Cherenkov, scintillating-fiber trackers and their spectrometer solenoids, and an electromagnetic calorimeter. The Phase 2 system will add the cooling channel components, including liquid-hydrogen absorbers embedded in superconducting Focus Coil solenoids, 201-MHz normal conducting RF cavities, and their surrounding Coupling Coil solenoids. The MICE Collaboration goal is to complete the experiment by 2010; progress toward this is discussed

Reproducibility of disc and macula optical coherence tomography using the Canon OCT-HS100 as compared with the Zeiss Cirrus HD-OCT.

Science.gov (United States)

Brautaset, Rune; Birkeldh, Ulrika; Rosén, Rebecka; Ramsay, Marika Wahlberg; Nilsson, Maria

2014-01-01

In a clinical setting, the usefulness of optical coherence tomography (OCT) is strongly dependent on reproducibility of the measurement. The aim of the present study was to evaluate macula and optic disc measurement reproducibility with the new spectral-domain OCT (SD-OCT) from Canon (Canon OCT-HS100) and to compare reproducibility and obtained measurements with the Zeiss Cirrus HD-OCT. Macula and optic disc parameters from the right eyes of 31 subjects were obtained twice with both instruments. Interoperator reproducibility was evaluated by use of the coefficient of repeatability (CR), and the obtained measurements were compared between the instruments. No difference in interoperator reproducibility could be found when comparing the 2 instruments and reproducibility ranged from 3.94% to 12.77% for optic disc parameters and from 1.19% to 3.54% for macula parameters. The lowest reproducibility was found for cup volume and vertical cup/disc ratio with both instruments. For all macula and retinal nerve fiber layer (RNFL) thickness measurements, there was a statistical difference when comparing the 2 instruments, except for RFNL measurements of the superior quadrant, with the Canon OCT-HS100 always evaluating the thickness to be thicker; however, the 2 instruments correlated well. The Canon OCT-HS100 is a reproducible instrument that matches the Zeiss Cirrus HD-OCT well. It remains to be evaluated how sensitive the Canon OCT-HS100 is to detect small subtle changes in optic disc parameters and macular nerve fiber layer thickness. Furthermore, due to the differences in thickness estimation, it is important to emphasize that SD-OCTs are not interchangeable.

Developing International Managers: The Contribution of Cultural Experience to Learning

Science.gov (United States)

Townsend, Peter; Regan, Padraic; Li, Liang Liang

2015-01-01

Purpose: The purpose of this paper is to evaluate cultural experience as a learning strategy for developing international managers. Design/methodology/approach: Using an integrated framework, two quantitative studies, based on empirical methodology, are conducted. Study 1, with an undergraduate sample situated in the Asia Pacific, aimed to examine…

Japanese International Female Students' Experience of Discrimination, Prejudice, and Stereotypes

Science.gov (United States)

Bonazzo, Claude; Wong, Y. Joel

2007-01-01

This qualitative study examined four Japanese international female college students' experience of discrimination, prejudice, and stereotypes in a predominately white university. Four themes emerged from the analysis of data: (1) overt forms of prejudice and discrimination; (2) stereotypes common to Asians; (3) stereotypes unique to the Japanese;…

Solid organ transplantation: the Italian experience in the international context.

Science.gov (United States)

Nanni Costa, A; De Cillia, C; Di Ciaccio, P; Rizzato, L; Venettoni, S

2011-01-01

The Italian experience in the organization of transplantation procedures could represent a relevant example of an internal development at a national level, combined with a strengthening of international collaborations. These results can be attributed first to the creation of the Italian National Transplant Centre (Centro Nazionale Trapianti [CNT]), and then to an ongoing European process that is leading to a greater awareness of the importance of closer collaboration between the organizations already existing and operating in the field of transplantation. This article summarizes the role and the most significant achievements of the CNT. Copyright © 2011. Published by Elsevier Inc.

Loss of international medical experiences: knowledge, attitudes and skills at risk.

Science.gov (United States)

Grudzen, Corita R; Legome, Eric

2007-11-28

Despite the great influence International Medical Experiences (IMs) can have on young physicians and their impact on patients and communities, they are not offered in all training programs and are at risk of being reduced in some due to stringent guidelines for funding of graduate medical education. IMs provide unique experiences in clinical, epidemiologic, cultural, and political arenas. From an educational perspective, they broaden a physician's differential diagnostic skills and introduce clinical entities rarely seen in the U.S. Time spent in developing countries emphasizes the importance of community health and increases cultural and linguistic competence. Experience working with the underserved during an IM has been shown to increase interest in volunteerism, humanitarian efforts, and work with underserved populations both in the US and abroad. IMs also afford physicians the opportunity to learn about the delivery of health care abroad and are associated with an increase in primary care specialty choice. It is time for the leaders in graduate medical education to prioritize international health opportunities. Leaders in academic medicine can press for changes in reimbursement patterns at the national level or special funds for international electives. Hospitals can set up separate accounts to help finance resident salaries and benefits while abroad. Individual departments must be flexible with resident schedules to allow elective time. Medical students and housestaff can organize and lobby larger organizations such as the American Medical Association (AMA), the American Association of Medical Colleges (AAMC), and specialty groups to make IMs universally accessible.

Overnight Hospital Experiences for Medical Students: Results of the 2014 Clerkship Directors in Internal Medicine National Survey.

Science.gov (United States)

Goren, Eric N; Leizman, Debra S; La Rochelle, Jeffrey; Kogan, Jennifer R

2015-09-01

Since the 2011 Accreditation Council of Graduate Medical Education (ACGME) work hour rules for residents were implemented, 24-30 h call for interns has been replaced by shift work, including night-float. The impact of these changes on undergraduate medical education experiences in internal medicine has not been described. We aimed to determine the current status of medical students' overnight experiences in Internal Medicine clerkships and sub-internships, and to assess internal medicine educators' perceptions of the importance of overnight work during internal medicine rotations. In May 2014, the Clerkship Directors in Internal Medicine (CDIM) conducted its annual survey. Twenty-eight questions about student participation in overnight work and perceptions of the importance of overnight work (rated on 1-5 Likert scale, 1 = very unimportant and 5 =  ery important) were included. Descriptive statistics were used to summarize responses. Free text results were analyzed qualitatively. The response rate was 78 %. A minority of respondents reported students having any overnight experience during the clerkship (38.7 %) or the sub-internship (40.7 %). Only 5 % of respondents reported having students assigned to night-float rotations outside of clerkships or sub-internships. Respondents agreed that overnight experiences were more important during the sub-internship than the clerkship, 4.0 ± 1.1 vs. 3.2 ± 1.2, p intern in particular was an important chance to practice providing emergency cross coverage and other intern roles. In the era of ACGME duty hours, there is a need to further examine whether there is a role for increased overnight hospital experiences for medical students.

Mentor experiences of international healthcare students' learning in a clinical environment: A systematic review.

Science.gov (United States)

Mikkonen, Kristina; Elo, Satu; Tuomikoski, Anna-Maria; Kääriäinen, Maria

2016-05-01

Globalisation has brought new possibilities for international growth in education and professional mobility among healthcare professionals. There has been a noticeable increase of international degree programmes in non-English speaking countries in Europe, creating clinical learning challenges for healthcare students. The aim of this systematic review was to describe mentors' experiences of international healthcare students' learning in a clinical environment. The objective of the review was to identify what influences the success or failure of mentoring international healthcare students when learning in the clinical environment, with the ultimate aim being to promote optimal mentoring practice. A systematic review was conducted according to the guidelines of the Centre for Reviews and Dissemination. Seven electronic databases were used to search for the published results of previous research: CINAHL, Medline Ovid, Scopus, the Web of Science, Academic Search Premiere, Eric, and the Cochrane Library. Search inclusion criteria were planned in the PICOS review format by including peer-reviewed articles published in any language between 2000 and 2014. Five peer-reviewed articles remained after the screening process. The results of the original studies were analysed using a thematic synthesis. The results indicate that a positive intercultural mentor enhanced reciprocal learning by improving the experience of international healthcare students and reducing stress in the clinical environment. Integrating international healthcare students into work with domestic students was seen to be important for reciprocal learning and the avoidance of discrimination. Many healthcare students were found to share similar experiences of mentoring and learning irrespective of their cultural background. However, the role of a positive intercultural mentor was found to make a significant difference for international students: such mentors advocated and mediated cultural differences and

The International Heat Pipe Experiment. [international cooperation zero g experiment

Science.gov (United States)

Mcintosh, R.; Ollendorf, S.; Harwell, W.

1976-01-01

The aims of the experiment are outlined. Flight experiments included in this program were provided by NASA, Goddard Space Flight Center, ESA (European Space Agency), the German Ministry of Technology, Hughes Aircraft Company and NASA, Ames Research Center.

International experiences in nursing education: a review of the literature.

Science.gov (United States)

Kulbok, Pamela A; Mitchell, Emma M; Glick, Doris F; Greiner, Doris

2012-04-24

Service learning and study abroad opportunities have become increasingly popular in nursing education in the past decade. The purpose of this systematic review was to explore existing literature concerning global health experiences in nursing education. Twenty-three empirical articles from 2003 to 2010 were reviewed, building upon existing reviews of international nursing education literature. Research on two-way exchange experiences and models for best practice were found to be lacking. While an array of countries were represented as the visiting or hosting side of the experience, few co-authors from host countries were found, particularly in literature originating from the U.S. The authors recommend that two-way exchange programs be evaluated to identify successful strategies and barriers to success. Ongoing evaluation of exchanges is necessary to ensure continued sustainable partnership and exchange in immersion experiences for nursing students.

Warnings on alcohol containers and advertisements: international experience and evidence on effects.

Science.gov (United States)

Wilkinson, Claire; Room, Robin

2009-07-01

In light of possible introduction of alcohol warning labels in Australia and New Zealand, this paper discusses the international experience with and evidence of effects of alcohol warning labels. The report describes international experience with providing information and warnings concerning the promotion or sale of alcoholic beverages, and considers the evidence on the effects of such information and warnings. The experience with and evaluations of the effects of tobacco warning labels are also considered. The most methodologically sound evaluations of alcohol warning labels are based on the US experience. Although these evaluations find little evidence that the introduction of the warning label in the USA had an impact on drinking behaviour, there is evidence that they led to an increase in awareness of the message they contained. In contrast, evaluations of tobacco warning labels find clear evidence of effects on behaviour. There is a need and opportunity for a rigorous evaluation of the impacts of introducing alcohol warning labels to add to the published work on their effectiveness. The experience with tobacco labels might guide the way for more effective alcohol warning labels. Alcohol warning labels are an increasingly popular alcohol policy initiative. It is clear that warning labels can be ineffective, but the tobacco experience suggests that effective warning labels are possible. Any introduction of alcohol warning labels should be evaluated in terms of effects on attitudes and behaviour.

Evaluation guide for the international reactor physics experiments evaluation project (IRPhEP)

International Nuclear Information System (INIS)

Yamaji, Akifumi

2013-01-01

At present, there is an urgent need to preserve integral reactor physics experimental data including separate or special effects data for nuclear energy and technology applications and the knowledge and competence contained therein. The International Reactor Physics Evaluation Project (IRPhEP) was initiated as a pilot activity in 1999 by the Organization of Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA) Nuclear Science Committee (NSC). The project was endorsed as an official activity of the NSC in June of 2003. While coordination and administration of the IRPhEP takes place at an international level, each participating country is responsible for the administration, technical direction, and priorities of the project within their respective countries. This document outlines the general presentation guidelines that evaluators should follow for the description of the experiments and all relevant experimental data in order to ensure the consistency between the evaluations published in the final Handbook. Publication templates will be used to ensure this consistency and will follow the general scheme below: 1 - Experiment identification number; 2- Date; 3 - Name of experiment (Purpose of experiment, Phenomena measured and scope); 4 - Name or designation of experimental programme; 5 - Description of facility; 6 - Description of test or experiment (Experimental configuration, Core life cycle, Experimental limitations or shortcomings); 7 - Phenomena measured (Description of results and analysis, Special features and characteristics of experiment, Measurement systems/methods and uncertainties); 8 - Duplicate or complementary experiments / other related experiments; 9 - Status of completion of the evaluation; 10 - References (pointer to evaluation, archive if available, otherwise generic bibliographic reference); 11 - Authors/ organisers 12 - Material available

The retrieval of cloud microphysical properties using satellite measurements and an in situ database

Directory of Open Access Journals (Sweden)

C. Poix

1996-01-01

Full Text Available By combining AVHRR data from the NOAA satellites with information from a database of in situ measurements, large-scale maps can be generated of the microphysical parameters most immediately significant for the modelling of global circulation and climate. From the satellite data, the clouds can be classified into cumuliform, stratiform and cirrus classes and then into further sub-classes by cloud top temperature. At the same time a database of in situ measurements made by research aircraft is classified into the same sub-classes and a statistical analysis is used to derive relationships between the sub-classes and the cloud microphysical properties. These two analyses are then linked to give estimates of the microphysical properties of the satellite observed clouds. Examples are given of the application of this technique to derive maps of the probability of occurrence of precipitating clouds and of precipitating water content derived from a case study within the International Cirrus Experiment (ICE held in 1989 over the North Sea.

The retrieval of cloud microphysical properties using satellite measurements and an in situ database

Directory of Open Access Journals (Sweden)

Christophe Poix

Full Text Available By combining AVHRR data from the NOAA satellites with information from a database of in situ measurements, large-scale maps can be generated of the microphysical parameters most immediately significant for the modelling of global circulation and climate. From the satellite data, the clouds can be classified into cumuliform, stratiform and cirrus classes and then into further sub-classes by cloud top temperature. At the same time a database of in situ measurements made by research aircraft is classified into the same sub-classes and a statistical analysis is used to derive relationships between the sub-classes and the cloud microphysical properties. These two analyses are then linked to give estimates of the microphysical properties of the satellite observed clouds. Examples are given of the application of this technique to derive maps of the probability of occurrence of precipitating clouds and of precipitating water content derived from a case study within the International Cirrus Experiment (ICE held in 1989 over the North Sea.

International human rights for mentally ill persons: the Ontario experience.

Science.gov (United States)

Zuckerberg, Joaquin

2007-01-01

This article is part of a working project which assesses Ontario's mental health legislation and practice vis-à-vis international human rights standards. The paper focuses on procedural safeguards provided by the major international human rights instruments in the field of mental health law such as the UN Principles for the Protection of Persons with Mental Illness (MI Principles) and the European Convention on Human Rights as interpreted by the European Human Rights Court. In analysing Ontario's compliance with international standards, the paper will explore some problems arising from the implementation of the legislation with which the author is familiar with from his experience as counsel for the Consent and Capacity Board. The paper aims to generate discussion for potential reforms in domestic legal systems and to provide a methodology to be used as a tool to assess similar mental health legislation in other local contexts.

The experiences of a small Canadian petroleum company in the international arena

International Nuclear Information System (INIS)

Rooney, J.

2002-01-01

Equatorial Energy Inc. is a small Canadian company that has succeeded in the international world of oil exploration and production. The 5 year old company has grown from zero to 13,000 boe/d through its engagement in the acquisition, exploration and development of petroleum and natural gas in Western Canada and Indonesia. Finding costs are getting higher as domestic sedimentary basins mature. This results in higher decline rates and fewer opportunities for growth. However, the international energy sector has become more accessible to small- and medium-sized companies due to the removal of political barriers and better access to new technologies. The support of capital markets and international experience also contributes to greater success in accessing the international energy sector. 16 figs

Integrated Networks: National and International Online Experiences

Directory of Open Access Journals (Sweden)

Osvaldo Muniz-Solari

2009-02-01

Full Text Available There is an increasing impression among online geography educators that interaction can be developed based on specific teaching and learning methods. The authors developed a practical research study to investigate this issue. The study was based on advanced graduate courses in geography at Beijing Normal University and Texas State University. International interaction was complemented by online collaboration among the US local group. Both synchronous and asynchronous communication systems were used, which spanned two platforms. Results of this experience indicate that teaching and learning methods must be enhanced by a flexible online learning model and extensive organizational support in order to increase interaction and reach a certain level of cooperation.

International cooperation in the Space Station programme - Assessing the experience to date

Science.gov (United States)

Logsdon, John M.

1991-01-01

The origins and framework for cooperation in the Space Station program are outlined. Particular attention is paid to issues and commitments between the countries and to the political context of the Station partnership. A number of conclusions concerning international cooperation in space are drawn based on the Space Station experience. Among these conclusions is the assertion that an international partnership requires realistic assesments, mutual trust, and strong commitments in order to work.

The Experiences of International Nursing Students in a Baccalaureate Nursing Program.

Science.gov (United States)

Sanner, Susan; Wilson, Astrid H.; Samson, Linda F.

2002-01-01

Eight female Nigerians studying nursing in the United States experienced social isolation, became resolved to acceptance of antagonistic attitudes encountered in the program, and persisted in spite of obstacles. From their experiences, recommendations for the adjustment of international students were developed. (Contains 20 references.) (SK)

International study on nurses' views and experiences of compassion.

Science.gov (United States)

Papadopoulos, I; Zorba, A; Koulouglioti, C; Ali, S; Aagard, M; Akman, O; Alpers, L-M; Apostolara, P; Biles, J; Martín-García, Á; González-Gil, T; Kouta, C; Krepinska, R; Kumar, B N; Lesińska-Sawicka, M; Lopez, L; Malliarou, M; Nagórska, M; Nissim, S; Nortvedt, L; Oter-Quintana, C; Ozturk, C; Pangilinan, S B; Papp, K; Eldar Regev, O; Rubiano, F O; Tolentino Diaz, M Y; Tóthová, V; Vasiliou, M

2016-09-01

Compassion is considered the cornerstone of nursing practice. However, the recent failures in delivering high-quality compassionate nursing care in the UK's National Health Service have brought the topic of compassion to the attention of the public, service providers, policy makers and academics. The aim of this study was to explore the nurses' views and experiences of a number of compassion-related issues in nursing and describe similarities and differences at an international level as well as from the different nursing roles of the participating nurses. An exploratory, cross-sectional descriptive study, using the International Online Compassion Questionnaire. A total of 1323 nurses from 15 countries completed the questionnaire. The majority of participants (59.5%) defined compassion as "Deep awareness of the suffering of others and wish to alleviate it" but definitions of compassion varied by country. Of participants, 69.6% thought compassion was very important in nursing and more than half (59.6%) of them argued that compassion could be taught. However, only 26.8% reported that the correct amount and level of teaching is provided. The majority of the participants (82.6%) stated that their patients prefer knowledgeable nurses with good interpersonal skills. Only 4.3% noted that they are receiving compassion from their managers. A significant relationship was found between nurses' experiences of compassion and their views about teaching of compassion. Our study is unique in identifying the views and experiences of nurses from 15 different countries worldwide. The findings reveal that compassion is neither addressed adequately in nursing education nor supported in the practice environment by managers. Self-report bias was inherent to our survey study design. Furthermore, the individual cultural differences and similarities in the findings are difficult to extrapolate owing to the fact that our analysis was at country level, as well as at the level of the

In situ measurements of tropical cloud properties in the West African Monsoon: upper tropospheric ice clouds, Mesoscale Convective System outflow, and subvisual cirrus

Directory of Open Access Journals (Sweden)

W. Frey

2011-06-01

Full Text Available In situ measurements of ice crystal size distributions in tropical upper troposphere/lower stratosphere (UT/LS clouds were performed during the SCOUT-AMMA campaign over West Africa in August 2006. The cloud properties were measured with a Forward Scattering Spectrometer Probe (FSSP-100 and a Cloud Imaging Probe (CIP operated aboard the Russian high altitude research aircraft M-55 Geophysica with the mission base in Ouagadougou, Burkina Faso. A total of 117 ice particle size distributions were obtained from the measurements in the vicinity of Mesoscale Convective Systems (MCS. Two to four modal lognormal size distributions were fitted to the average size distributions for different potential temperature bins. The measurements showed proportionately more large ice particles compared to former measurements above maritime regions. With the help of trace gas measurements of NO, NO_y, CO₂, CO, and O₃ and satellite images, clouds in young and aged MCS outflow were identified. These events were observed at altitudes of 11.0 km to 14.2 km corresponding to potential temperature levels of 346 K to 356 K. In a young outflow from a developing MCS ice crystal number concentrations of up to (8.3 ± 1.6 cm⁻³ and rimed ice particles with maximum dimensions exceeding 1.5 mm were found. A maximum ice water content of 0.05 g m⁻³ was observed and an effective radius of about 90 μm. In contrast the aged outflow events were more diluted and showed a maximum number concentration of 0.03 cm⁻³, an ice water content of 2.3 × 10⁻⁴ g m⁻³, an effective radius of about 18 μm, while the largest particles had a maximum dimension of 61 μm.

Close to the tropopause subvisual cirrus were encountered four times at altitudes of 15 km to 16.4 km. The mean ice particle number concentration of these encounters was 0.01 cm⁻³ with maximum particle sizes of 130 �

Swedish experiences in implementing national and international safeguards

International Nuclear Information System (INIS)

Nilsson, A.; Elborn, M.; Grahn, P.

1991-01-01

This paper reports that international safeguards have been applied in Sweden since the early 70s. Experiences have been achieved from exclusive bilateral and trilateral control followed by NPT safeguards in 1975. The Swedish State System for accountancy and Control (SSAC) includes all regulations that follows from prevailing obligations regarding the peaceful uses of nuclear material. The system has been developed in cooperation between the national authority, the Swedish Nuclear Power Inspectorate (SKI) and the Swedish nuclear industry. The paper presents experiences from the practical implementation of the SSAC and the IAEA safeguards system, gained by the SKI and the nuclear industry, respectively. Joint approaches and solutions to some significant safeguards issues are presented. The cooperation between the nuclear industry and the authority in R and D activities, in particular with respect to the Swedish Support Program is highlighted, e.g. the use of nuclear facilities in development or training tasks. some of the difficulties encountered with the system are also touched upon

The Alpha Magnetic Spectrometer (AMS) experiment on the International Space Station

Energy Technology Data Exchange (ETDEWEB)

Alpat, Behcet E-mail: behcet.alpat@pg.infn.it

2001-04-01

The Alpha Magnetic Spectrometer (AMS) is a detector designed to operate in space to search for antimatter components in cosmic ray, the annihilation products of darkmatter and to study the antiprotons, positrons and light nuclei. A 'baseline' version of the experiment has successfully completed the precursor flight on Space Shuttle Discovery (June 2-12, 1998). The complete AMS is programmed for installation on International Space Station in year 2003 for an operational period of 3 years. In this contribution we report on the experimental configuration of AMS that will be installed on International Space Station.

International Microgrid Assessment. Governance, INcentives, and Experience (IMAGINE)

Energy Technology Data Exchange (ETDEWEB)

Marnay, Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhou, Nan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Qu, Min [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Romankiewicz, John [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2012-06-01

Microgrids can provide an avenue for increasing the amount of distributed generation and delivery of electricity, where control is more dispersed and quality of service is locally tailored to end-use requirements. Much of this functionality is very different from the predominant utility model to date of centralized power production which is then transmitted and distributed across long distances with a uniform quality of service. This different functionality holds much promise for positive change, in terms of increasing reliability, energy efficiency, and renewable energy while decreasing and carbon emissions. All of these functions should provide direct cost savings for customers and utilities as well as positive externalities for society. As we have seen from the international experience, allowing microgrids to function in parallel with the grid requires some changes in electricity governance and incentives to capture cost savings and actively price in positive externalities. If China can manage to implement these governance changes and create those incentive policies, it will go beyond the establishment of a successful microgrid demonstration program and become an international leader in microgrid deployment.

Ice Nucleation of Soot Particles in the Cirrus Regime: Is Pore Condensation and Freezing Relevant for Soot?

Science.gov (United States)

Kanji, Z. A.; Mahrt, F.; David, R.; Marcolli, C.; Lohmann, U.; Fahrni, J.; Brühwiler, D.

2017-12-01

Heterogeneous ice nucleation (HIN) onto soot particles from previous studies have produced inconsistent results of temperature and relative humidity conditions required for freezing depending on the source of soot particle investigated. The ability of soot to act as HIN depended on the type of soot and size of particle. Often homogenous freezing conditions or water saturation conditions were required to freeze soot particles, rendering HIN irrelevant. Using synthesised mesoporous silica particles, we show pore condensation and freezing works with experiments performed in the Zurich Ice Nucleation Chamber (ZINC). By testing a variety of soot particles in parallel in the Horizontal Ice Nucleation Chamber (HINC), we suggest that previously observed HIN on soot particles is not the responsible mechanism for ice formation. Laboratory generated CAST brown and black soot, commercially available soot and acid treated soot were investigated for their ice nucleation abilities in the mixed-phase and cirrus cloud temperature regimes. No heterogeneous ice nucleation activity is inferred at T > -38 °C (mixed-phase cloud regime), however depending on particle size and soot type, HIN was observed for T nucleation of ice in the pores or cavities that are ubiquitous in soot particles between the primary spherules. The ability of some particles to freeze at lower relative humidity compared to others demonstrates why hydrophobicity plays a role in ice nucleation, i.e. controlling the conditions at which these cavities fill with water. Thus for more hydrophobic particles pore filling occurs at higher relative humidity, and therefore freezing of pore water and ice crystal growth. Future work focusses on testing the cloud processing ability of soot particles and water adsorption isotherms of the different soot samples to support the hydrophobicity inferences from the ice nucleation results.

[Experience of international cooperation among Baltic countries in occupational health and security].

Science.gov (United States)

Miloutka, E V; Andronova, E R; Dedkova, L E

2013-01-01

The article covers longstanding experience of international cooperation in occupational health and security with Baltic countries. The authors describe history of information network creation, its structure, objectives, importance for occupational health services and safety in the region.

The acculturation, language and learning experiences of international nursing students: Implications for nursing education.

Science.gov (United States)

Mitchell, Creina; Del Fabbro, Letitia; Shaw, Julie

2017-09-01

International or foreign students are those who enrol in universities outside their country of citizenship. They face many challenges acculturating to and learning in a new country and education system, particularly if they study in an additional language. This qualitative inquiry aimed to explore the learning and acculturating experiences of international nursing students to identify opportunities for teaching innovation to optimise the experiences and learning of international nursing students. Undergraduate and postgraduate international nursing students were recruited from one campus of an Australian university to take part in semi-structured interviews. A purposive and theoretically saturated sample of 17 students was obtained. Interviews were audio-recorded and field notes and interview data were thematically analysed. Expressing myself and Finding my place were the two major themes identified from the international student data. International nursing students identified that it took them longer to study in comparison with domestic students and that stress negatively influenced communication, particularly in the clinical setting. Additionally international nursing students identified the need to find supportive opportunities to speak English to develop proficiency. Clinical placement presented the opportunity to speak English and raised the risk of being identified as lacking language proficiency or being clinically unsafe. Initially, international nursing students felt isolated and it was some time before they found their feet. In this time, they experienced otherness and discrimination. International nursing students need a safe place to learn so they can adjust and thrive in the university learning community. Faculty and clinical educators must be culturally competent; they need to understand international nursing students' needs and be willing and able to advocate for and create an equitable environment that is appropriate for international nursing

Comparing the Experiences and Needs of Postsecondary International Students from China and South Korea

Science.gov (United States)

Deters, Ping

2015-01-01

International students from China and South Korea are an increasingly important part of the international student body in many English-medium postsecondary institutions. The purpose of this qualitative study was to gain a deeper understanding of the experiences and needs of these two groups of students at a Canadian postsecondary institution. Data…

Cooperative Policies and African International Students: Do Policy Spirits Match Experiences?

Science.gov (United States)

McLellan, Carlton E.

2009-01-01

This paper explores the policy implications of experiences of African international students (AIS) studying at post-apartheid South Africa universities. It argues that given the spirit and tone of continental, regional, and domestic policies to which South Africa has committed that at the very least there is an implicit expectation of…

Polarized Radiative Transfer of a Cirrus Cloud Consisting of Randomly Oriented Hexagonal Ice Crystals: The 3 x 3 Approximation for Non-Spherical Particles

Science.gov (United States)

Stamnes, S.; Ou, S. C.; Lin, Z.; Takano, Y.; Tsay, S. C.; Liou, K.N.; Stamnes, K.

2016-01-01

The reflection and transmission of polarized light for a cirrus cloud consisting of randomly oriented hexagonal columns were calculated by two very different vector radiative transfer models. The forward peak of the phase function for the ensemble-averaged ice crystals has a value of order 6 x 10(exp 3) so a truncation procedure was used to help produce numerically efficient yet accurate results. One of these models, the Vectorized Line-by-Line Equivalent model (VLBLE), is based on the doubling- adding principle, while the other is based on a vector discrete ordinates method (VDISORT). A comparison shows that the two models provide very close although not entirely identical results, which can be explained by differences in treatment of single scattering and the representation of the scattering phase matrix. The relative differences in the reflected I and Q Stokes parameters are within 0.5 for I and within 1.5 for Q for all viewing angles. In 1971 Hansen showed that for scattering by spherical particles the 3 x 3 approximation is sufficient to produce accurate results for the reflected radiance I and the degree of polarization (DOP), and he conjectured that these results would hold also for non-spherical particles. Simulations were conducted to test Hansen's conjecture for the cirrus cloud particles considered in this study. It was found that the 3 x 3 approximation also gives accurate results for the transmitted light, and for Q and U in addition to I and DOP. For these non-spherical ice particles the 3 x 3 approximation leads to an absolute error 2 x 10(exp -6) for the reflected and transmitted I, Q and U Stokes parameters. Hence, it appears to be an excellent approximation, which significantly reduces the computational complexity and burden required for multiple scattering calculations.

NASA Glenn Research Center Solar Cell Experiment Onboard the International Space Station

Science.gov (United States)

Myers, Matthew G.; Wolford, David S.; Prokop, Norman F.; Krasowski, Michael J.; Parker, David S.; Cassidy, Justin C.; Davies , William E.; Vorreiter, Janelle O.; Piszczor, Michael F.; Mcnatt, Jeremiah S.;

Retrieval of Cirrus Cloud Optical Depth under Day and Night Conditions from MODIS Collection 6 Cloud Property Data

Directory of Open Access Journals (Sweden)

Andrew K. Heidinger

2015-06-01

Full Text Available This paper presents a technique to generate cirrus optical depth and particle effective size estimates from the cloud emissivities at 8.5, 11 and 12 μm contained in the Collection-6 (C6 MYD06 cloud product. This technique employs the latest scattering models and scattering radiative transfer approximations to estimate cloud optical depth and particle effective size using efficient analytical formulae. Two scattering models are tested. The first is the same scattering model as that used in the C6 MYD06 solar reflectance products. The second model is an empirical model derived from radiometric consistency. Both models are shown to generate optical depths that compare well to those from constrained CALIPSO retrievals and MYD06. In terms of effective radius retrievals, the results from the radiometric empirical model agree more closely with MYD06 than those from the C6 model. This analysis is applied to AQUA/MODIS data collocated with CALIPSO/CALIOP during January 2010.

The 27-28 October 1986 FIRE IFO cirrus case study: Comparison of satellite and aircraft derived particle size

Science.gov (United States)

Wielicki, Bruce A.; Suttles, J. T.; Heymsfield, Andrew J.; Welch, Ronald M.; Spinhirne, James D.; Wu, Man-Li C.; Starr, David; Parker, Lindsay; Arduini, Robert F.

1990-01-01

Theoretical calculations predict that cloud reflectance in near infrared windows such as those at 1.6 and 2.2 microns should give lower reflectances than at visible wavelengths. The reason for this difference is that ice and liquid water show significant absorption at those wavelengths, in contrast to the nearly conservative scattering at wavelengths shorter than 1 micron. In addition, because the amount of absorption scales with the path length of radiation through the particle, increasing cloud particle size should lead to decreasing reflectances at 1.6 and 2.2 microns. Measurements at these wavelengths to date, however, have often given unpredicted results. Twomey and Cocks found unexpectedly high absorption (factors of 3 to 5) in optically thick liquid water clouds. Curran and Wu found expectedly low absorption in optically thick high clouds, and postulated the existence of supercooled small water droplets in place of the expected large ice particles. The implications of the FIRE data for optically thin cirrus are examined.

Proceedings of the 2014 ACM international conference on Interactive experiences for TV and online video

NARCIS (Netherlands)

P. Olivier (Patrick); P. Wright; T. Bartindale; M. Obrist (Marianna); P.S. Cesar Garcia (Pablo Santiago); S. Basapur

2014-01-01

htmlabstractIt is our great pleasure to introduce the 2014 ACM International Conference on Interactive Experiences for Television and Online Video -- ACM TVX 2014. ACM TVX is a leading annual conference that brings together international researchers and practitioners from a wide range of

Competition in electricity markets: international experience and the case of Italy

International Nuclear Information System (INIS)

Ferrari, A.; Giulietti, M.

2005-01-01

As a result of European Directives 96/92 and 2003/54 on the liberalisation of the internal market for electricity, the Italian electricity sector has been subject to extensive institutional changes which have affected the competitive nature of the market. In this paper we attempt to assess the likely effect of these institutional changes on the Italian electricity industry, and focus particularly on the impact of the introduction of a centralised wholesale market. The assessment of the likely impact of these institutional changes is based on the comparison with the international experience of countries where extensive liberalisation measures have been implemented (such as the US, UK and the Scandinavian region). On the basis of this international comparison, we draw some lessons about how to promote effective competition in the Italian market and in other electricity markets which have not been fully liberalised. (Author)

Sensitivity of Cirrus and Mixed-phase Clouds to the Ice Nuclei Spectra in McRAS-AC: Single Column Model Simulations

Science.gov (United States)

Betancourt, R. Morales; Lee, D.; Oreopoulos, L.; Sud, Y. C.; Barahona, D.; Nenes, A.

2012-01-01

The salient features of mixed-phase and ice clouds in a GCM cloud scheme are examined using the ice formation parameterizations of Liu and Penner (LP) and Barahona and Nenes (BN). The performance of LP and BN ice nucleation parameterizations were assessed in the GEOS-5 AGCM using the McRAS-AC cloud microphysics framework in single column mode. Four dimensional assimilated data from the intensive observation period of ARM TWP-ICE campaign was used to drive the fluxes and lateral forcing. Simulation experiments where established to test the impact of each parameterization in the resulting cloud fields. Three commonly used IN spectra were utilized in the BN parameterization to described the availability of IN for heterogeneous ice nucleation. The results show large similarities in the cirrus cloud regime between all the schemes tested, in which ice crystal concentrations were within a factor of 10 regardless of the parameterization used. In mixed-phase clouds there are some persistent differences in cloud particle number concentration and size, as well as in cloud fraction, ice water mixing ratio, and ice water path. Contact freezing in the simulated mixed-phase clouds contributed to transfer liquid to ice efficiently, so that on average, the clouds were fully glaciated at T approximately 260K, irrespective of the ice nucleation parameterization used. Comparison of simulated ice water path to available satellite derived observations were also performed, finding that all the schemes tested with the BN parameterization predicted 20 average values of IWP within plus or minus 15% of the observations.

Experience of Education in the International Classroom--A Systematic Literature Review

Science.gov (United States)

Safipour, Jalal; Wenneberg, Stig; Hadziabdic, Emina

2017-01-01

In this essay, we investigate the learning and teaching experiences in the international classroom from both the teachers and the students' perspectives. The findings of this study showed that language barriers are one of the difficulties, but academic cultural differences seem to play a more important role that can impact on the learning outcomes…

Feedback from Westinghouse experience on segmentation of reactor vessel internals - 59013

International Nuclear Information System (INIS)

Kreitman, Paul J.; Boucau, Joseph; Segerud, Per; Fallstroem, Stefan

2012-01-01

With more than 25 years of experience in the development of reactor vessel internals segmentation and packaging technology, Westinghouse has accumulated significant know-how in the reactor dismantling market. Building on tooling concepts and cutting methodologies developed decades ago for the successful removal of nuclear fuel from the damaged Three Mile Island Unit 2 reactor (TMI-2), Westinghouse has continuously improved its approach to internals segmentation and packaging by incorporating lessons learned and best practices into each successive project. Westinghouse has developed several concepts to dismantle reactor internals based on safe and reliable techniques, including plasma arc cutting (PAC), abrasive water-jet cutting (AWJC), metal disintegration machining (MDM), or mechanical cutting. Westinghouse has applied its technology to all types of reactors covering Pressurized Water Reactors (PWR's), Boiling Water Reactors (BWR's), Gas Cooled Reactors (GCR's) and sodium reactors. The primary challenges of a segmentation and packaging project are to separate the highly activated materials from the less-activated materials and package them into appropriate containers for disposal. Since space is almost always a limiting factor it is therefore important to plan and optimize the available room in the segmentation areas. The choice of the optimum cutting technology is important for a successful project implementation and depends on some specific constraints like disposal costs, project schedule, available areas or safety. Detailed 3-D modeling is the basis for tooling design and provides invaluable support in determining the optimum strategy for component cutting and disposal in waste containers, taking account of the radiological and packaging constraints. Westinghouse has also developed a variety of special handling tools, support fixtures, service bridges, water filtration systems, video-monitoring systems and customized rigging, all of which are required for a

Creating International Community Service Learning Experiences in a Capstone Marketing-Projects Course

Science.gov (United States)

Metcalf, Lynn E.

2010-01-01

This article outlines the development of a project-based capstone marketing course, specifically designed to provide marketing students with an international community service learning experience. It differs significantly from previous studies, which focus on integrating service learning into existing marketing courses and on helping local…

Cost related to nuclear power plants: the international experience

International Nuclear Information System (INIS)

1995-03-01

This report about the international costs of nuclear electricity generations is divided in two distinct parts: the first one shows the competitiveness of the main sources of electricity generation for base load operation according to studies carried on by OECD and UNIPEDE since 1983; the second one discusses the most recent OECD study about the different types of power plants to be constructed in its number states, based on the experience of each country and the technology evolution of the different fuels used. (F.E.). 4 refs, 2 figs, 27 tab

Learning in an Online Distance Education Course: Experiences of Three International Students

Directory of Open Access Journals (Sweden)

Zuochen Zhang

2010-03-01

Full Text Available This case study explores the learning experiences of three international students who were enrolled in an online master’s program offered by a large university in Canada. The aim of the study was to understand the international students’ experiences with, and perspectives on, the online learning environment. Findings indicate that previous education and especially language proficiency strongly impacted the learning of these students in this environment. Non-native English speakers required considerably more time to process readings and postings and to make postings themselves. Their lack of familiarity with the details of North American culture and colloquial language made it difficult to follow much of the course discussion. They also tended to avoid socializing in the course, which left them at the periphery of course activities. Based on these findings, the authors make the following recommendations for designers and instructors of online courses: 1 Raise the English language proficiency requirement for graduate admissions into online programs because the text-based communication in a CMC space requires interpreting messages without non-verbal cues; 2 Ensure that online distance education course designers are aware of the needs and expectations of international students; and 3 Combine the design principles from both traditional and constructivism theories.

Leaping into the Unknown: Experience of Counseling Students Participating in Group Work with International Students

Science.gov (United States)

Choi, Kyoung Mi; Protivnak, Jake J.

2016-01-01

This research study used qualitative phenomenological methodology to explore counseling graduate students' experiences leading support groups for international students. Participants included 6 master's-level counseling students. The following 4 themes emerged to describe the counseling students' experience as group leaders: (a) individualistic…

Teaching Business Classes Abroad: How International Experience Benefits Faculty, Students, and Institutions

Science.gov (United States)

Miglietti, Cynthia

2015-01-01

International educational experiences can provide benefits for faculty members as well as higher education institutions and their students. The opportunity to lecture and conduct research with colleagues at universities in other countries can foster the globalization or internationalization of academic teaching, the advancement of knowledge, and…

Internationalization of British Universities: Learning from the Experiences of International Counselling Students

Science.gov (United States)

Pattison, Sue; Robson, Sue

2013-01-01

This retrospective qualitative study investigated the experiences of 12 international students in a postgraduate counselling programme at a higher education (HE) institution in the UK. Results from an earlier empirical study on these students (Pattison, "Counselling and Psychotherapy Research" 3: 107-113, 2003) were mapped against…

The Voluntariat: A Frieirean framework to understand the nature of undergraduate international (medical) experiences.

Science.gov (United States)

Qaiser, Seemi; Dimaras, Helen; Hamel, Paul

2016-12-01

Despite literature documenting limited and asymmetrical benefits along with ethical issues, short-term international volunteering is increasingly popular among North American university students as a perceived advantage when applying to professional healthcare schools or the job market. Academic institutions are also encouraging students to pursue international experiences in order to cultivate values as global citizens. These experiences are most typically limited to economically privileged students. Furthermore, international activities in developing countries often lack a pedagogy of social justice and may confirm a simplistic understanding of development. Brazilian educator Paulo Freire's "liberation pedagogy" provides a framework for understanding the limitations of international volunteering, whereby the presence of privileged volunteers implementing Western models of development may hinder aspects of local movements. Regardless, university students face intense competition in accessing opportunities, such as medical school, and pay large sums to participate in volunteering to strengthen their academic credentials. We propose that these students form "the voluntariat." They simultaneously play two roles by, first, contributing to the conditions that oppress the very communities in which they volunteer and, second, by playing a role as objects of oppression by the liberal institutions of learning and employment to which they are attempting to gain access.

The Emergence of a Regional Hub: Comparing International Student Choices and Experiences in South Korea

Science.gov (United States)

Jon, Jae-Eun; Lee, Jenny J.; Byun, Kiyong

2014-01-01

As the demand for international education increases, middle-income non-English speaking countries, such as South Korea, play an increasing role in hosting the world's students. This mixed-methods study compares the different motivations and experiences of international students within and outside the East Asian region. Based on findings, this…

International research and development projects in nuclear energy: Experience and future prospects

International Nuclear Information System (INIS)

Strohl, P.

1983-01-01

From the very beginning nuclear energy appeared as a fruitful field for international co-operation and particularly for international projects and joint ventures. By pooling scientific, technical and financial resources, the participating countries sought to promote the development of technology and the transition of nuclear energy to the industrial stage. Governments and therefore intergovernmental organizations were the driving force behind the establishment of joint projects in various R and D sectors, often in association with industry and private research institutes. The situation changed considerably from the end of the 1960s onwards. Despite some remarkable technical achievements, international co-operation did not develop to the extent predicted at the outset. Industry took over in the exploitation of proven technologies, and industrial co-operation agreements have become an important feature in some key areas of nuclear energy. This trend raises questions as to the future of joint R and D projects organized through intergovernmental co-operation. Although such projects are still very useful, they tend to be concentrated in those few sectors which continue to be of direct interest to the Governments; for instance, fundamental research, radioactive waste management and nuclear safety. The position of nuclear energy has changed, and the benefits to be drawn from this form of international co-operation must be critically re-assessed accordingly. While advantage to be gained from international projects for countries which are the most advanced in the development of nuclear energy is not the same as it was at the beginning, the transfer of experience and knowledge to less advanced countries is still the main concern of projects dealing with safety and regulatory matters. The experience thus gained provides a very useful insight into the legal and institutional framework of joint projects

Inspection of the coupling part material degradation. Some experiences and results from SKODA JS related to internals

International Nuclear Information System (INIS)

Brynda, J.

1998-01-01

In this presentation some experiences and results from SKODA JS, related to internals, are reported. Sketches of the construction of WWER 440 RPV and internal's materials, including chemical composition are given. The results of hardness tests on internal parts are reported as well as some changes in the construction of internal parts which were made to improve their crack and fracture properties

The International Experience of Regional Development of Creative Industries

Directory of Open Access Journals (Sweden)

Turskyj Ihor V.

2017-12-01

Full Text Available The article is aimed at generalizing the international experience of regional development of creative industries and defining directions of its implementation in Ukraine. The experience of the world countries on regional development of creative industries has been generalized, tendencies and specificity of these development processes have been identified. The interrelation of the process of development of creative industries with innovation development of regions has been defined. Prospects for development of creative industries in regions of Ukraine have been identified and directions of implementation of foreign experience have been suggested. Thus, strategic measures for the development of creative clusters can be the corresponding priorities of cultural policy in the regions, the development of specific projects and programs, the opening of art-incubators, the creation of a favorable investment climate, financial and tax incentives as conditions for interaction between creativity and business. The scale and dynamics of the world’s creative sector, which has a significant potential for growth and less vulnerability in financial-economic crises compared to the traditional sector, gives chance to high expectations for the development of creative industries in Ukraine as well.

Learning and Growing in a "Foreign" Context: Intercultural Experiences of International Students

Science.gov (United States)

Gu, Qing; Schweisfurth, Michele; Day, Christopher

2010-01-01

This paper discusses the background and key findings of a two-year Economic and Social Research Council (ESRC) funded mixed-method research project (2006-2008) which was designed, within the context of university internationalisation, to provide an investigation of the experiences of first-year international students during their undergraduate…

International Experiences as Professional Development to Enhance Classroom Practice: Beyond Educational Tourism

Science.gov (United States)

Johnson, John William, III

2012-01-01

Professional development of educators is a central feature in education reform efforts (Bredeson, 2000) and school improvement (Guskey & Huberman, 1995). The purpose of the study was to describe personal and professional gains from an international experience, notably the Fulbright-Hays Group Study Abroad Program, including new knowledge and…

Embedding International Experiences in Business Curriculum Design: Cultivating a Study Abroad Program

Science.gov (United States)

Babb, Jeffry; Womble, Lynsee A.; De'Armond, De'Arno

2013-01-01

In business education, the impacts of the globalization of markets, financial institutions, and economies exert increasing influence on the curriculum in business schools. Schools of business recognize the need to embed international experiences into their curriculum in order to prepare students for global context of the marketplace. Often,…

A missing piece of the workforce puzzle. The experiences of internationally qualified nurses in New Zealand: a literature review.

Science.gov (United States)

Jenkins, Brittany Lauren; Huntington, Annette

2015-01-01

To analyse the literature regarding the context and experiences of internationally qualified registered nurses, particularly Filipino and Indian nurses, who have transitioned to New Zealand. Internationally qualified nurses are a significant proportion of the nursing workforce in many developed countries including New Zealand. This is increasingly important as populations age, escalating demand for nurses. Understanding the internationally qualified nurse experience is required as this could influence migration in a competitive labour market. Examination of peer-reviewed research, policy and discussion documents, and technical reports. A systematic literature search sought articles published between 2001 and 2014 using Google Scholar, CINAHL, and Medline. Articles were critically appraised for relevance, transferability, and methodological rigour. Fifty-one articles met inclusion criteria and demonstrate internationally qualified nurses face significant challenges transitioning into New Zealand. The internationally qualified nurse experience of transitioning into a new country is little researched and requires further investigation.

A quality control of proteomic experiments based on multiple isotopologous internal standards

Directory of Open Access Journals (Sweden)

Adele Bourmaud

2015-09-01

Full Text Available The harmonization of proteomics experiments facilitates the exchange and comparison of results. The definition of standards and metrics ensures reliable and consistent data quality. An internal quality control procedure was developed to assess the different steps of a proteomic analysis workflow and perform a system suitability test. The method relies on a straightforward protocol using a simple mixture of exogenous proteins, and the sequential addition of two sets of isotopically labeled peptides added to reference samples. This internal quality control procedure was applied to plasma samples to demonstrate its easy implementation, which makes it generic for most proteomics applications.

Financing energy projects: experience of the International Finance Corporation

International Nuclear Information System (INIS)

Bond, Gary; Carter, Laurence

1995-01-01

This paper provides an overview of the recent trend towards private ownership and financing of power projects in the developing countries, focusing on the role played by both private and public agencies in meeting the large financing challenges. The paper draws upon the operational experience of the International Finance Corporation, which has been involved in the financing of more than 30 private power projects in the developing countries over the past three decades. Among the issues that affect implementation of private power projects is the balancing of risk and reward to equity investors and to commercial lenders. The paper discusses the principal sources of risk and the strategies used to manage them. A related issue is the competition for capital on the international markets, and the techniques that are being devised to bring more finance to the power sector. Finally, the paper considers the role of government in bringing private investors to the power sector, and the approaches being adopted to balance the needs of investors with the needs of the public. (author)

Competition in electricity spot markets. Economic theory and international experience

Energy Technology Data Exchange (ETDEWEB)

Fehr, Nils-Henrik von der; Harbord, David

1998-09-01

This publication gives a survey of economic theory and international experience connected to electricity spot markets. The main purpose is to consider the attempts that have been made to apply economic theory and empirical methods to the analysis of electricity markets, and to evaluate them in light of theoretical considerations and empirical evidence. The publication describes in simple terms the basic pool pricing mechanism, and experience with pools in a number of countries. It is worth emphasizing that it is not the purpose to treat in extensive detail the structure of electricity pools around the world. Key factors of the markets in England and Wales, Norway and Australia are described in order to allow for a comparison of design issues and evaluation of competitive performance. 80 refs., 14 figs., 15 tabs.

Superconducting solenoids for an international muon cooling experiment

International Nuclear Information System (INIS)

Green, M.A.; Rey, J.M.

2002-01-01

The international muon ionization cooling experiment MICE will consist of two focusing cooling cells and a pair of uniform field solenoids used for particle identification and emittance measurements. The 2.75-meter long cooling cells have a pair of field flip coils and a coupling coil. The 0.52-meter diameter field flip coils surround an absorber that removes transverse and longitudinal momentum from the muons to be cooled. The beam in the absorber is at a minimum beta point so that scattering of the muons is minimized. The 1.7-meter diameter coupling coils are outside of conventional 201.25 MHz RF cavities that accelerate the muons putting longitudinal momentum into the muons without putting back the transverse momentum into the beam. A third set of flip coils helps the muon beam transition from and to the experimental solenoids. The 0.6-meter diameter experimental solenoids have a uniform field region (good to about 1 part in 1000) that is 1.3-meters long. The MICE experiment magnets must operate as a single unit so that the field profile will produce the maximum muon cooling

The Voluntariat: A Freirean framework to understand the nature of undergraduate international (medical experiences

Directory of Open Access Journals (Sweden)

Seemi Qaiser

2016-12-01

Full Text Available Despite literature documenting limited and asymmetrical benefits along with ethical issues, short-term international volunteering is increasingly popular among North American university students as a perceived advantage when applying to professional healthcare schools or the job market. Academic institutions are also encouraging students to pursue international experiences in order to cultivate values as global citizens. These experiences are most typically limited to economically privileged students. Furthermore, international activities in developing countries often lack a pedagogy of social justice and may confirm a simplistic understanding of development. Brazilian educator Paulo Freire’s “liberation pedagogy” provides a framework for understanding the limitations of international volunteering, whereby the presence of privileged volunteers implementing Western models of development may hinder aspects of local movements. Regardless, university students face intense competition in accessing opportunities, such as medical school, and pay large sums to participate in volunteering to strengthen their academic credentials. We propose that these students form “the voluntariat.” They simultaneously play two roles by, first, contributing to the conditions that oppress the very communities in which they volunteer and, second, by playing a role as objects of oppression by the liberal institutions of learning and employment to which they are attempting to gain access.

Experiments with HEU (93.14 wt.%) metal annuli with internal graphite cylinder

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiaobo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bess, John D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wehmann, Udo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mihalczo, John T. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-04-01

A variety of critical experiments were constructed of enriched uranium metal (oralloy ) during the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. The purposes of these experiments included the evaluation of storage, casting, and handling limits for the Y-12 Plant and providing data for verification of calculation methods and cross-sections for nuclear criticality safety applications. These included solid cylinders of various diameters, annuli of various inner and outer diameters, two and three interacting cylinders of various diameters, and graphite and polyethylene reflected cylinders and annuli. Of the hundreds of delayed critical experiments, only three experimental configurations are described here. They are internal graphite reflected metal uranium assemblies with three different diameter HEU annuli (15-9 inches, 15-7 inches and 13-7 inches). These experiments can be found in Reference 1 and in their associated logbook

First Nuclear Reaction Experiment with Stored Radioactive 56Ni Beam and Internal Hydrogen and Helium Targets

NARCIS (Netherlands)

Egelhof, P.; Bagchi, Soumya; Csatlós, M.; Dillmann, I.; Dimopoulou, C.; Furuno, T; Geissel, H.; Gernhauser, R.; Kalantar-Nayestanaki, Nasser; Kuilman, M.; Mahjour-Shafiei, M.; Najafi, M.A.; Rigollet, C.; Streicher, B.

2014-01-01

The investigation of light-ion induced direct reactions using stored and cooled radioactive beams, interacting with internal targets of storage rings, can lead to substantial advantages over external target experiments, in particular for direct reaction experiments in inverse kinematics at very low

Materials International Space Station Experiment (MISSE): Overview, Accomplishments and Future Needs

Science.gov (United States)

deGroh, Kim K.; Jaworske, Donald A.; Pippin, Gary; Jenkins, Philip P.; Walters, Robert J.; Thibeault, Sheila A.; Palusinski, Iwona; Lorentzen, Justin R.

2014-01-01

Materials and devices used on the exterior of spacecraft in low Earth orbit (LEO) are subjected to environmental threats that can cause degradation in material properties, possibly threatening spacecraft mission success. These threats include: atomic oxygen (AO), ultraviolet and x-ray radiation, charged particle radiation, temperature extremes and thermal cycling, micrometeoroid and debris impacts, and contamination. Space environmental threats vary greatly based on spacecraft materials, thicknesses and stress levels, and the mission environment and duration. For more than a decade the Materials International Space Station Experiment (MISSE) has enabled the study of the long duration environmental durability of spacecraft materials in the LEO environment. The overall objective of MISSE is to test the stability and durability of materials and devices in the space environment in order to gain valuable knowledge on the performance of materials in space, as well as to enable lifetime predictions of new materials that may be used in future space flight. MISSE is a series of materials flight experiments, which are attached to the exterior of the International Space Station (ISS). Individual experiments were loaded onto suitcase-like trays, called Passive Experiment Containers (PECs). The PECs were transported to the ISS in the Space Shuttle cargo bay and attached to, and removed from, the ISS during extravehicular activities (EVAs). The PECs were retrieved after one or more years of space exposure and returned to Earth enabling post-flight experiment evaluation. MISSE is a multi-organization project with participants from the National Aeronautics and Space Administration (NASA), the Department of Defense (DoD), industry and academia. MISSE has provided a platform for environmental durability studies for thousands of samples and numerous devices, and it has produced many tangible impacts. Ten PECs (and one smaller tray) have been flown, representing MISSE 1 through MISSE

Coming to America for Spiritual or Academic Growth? Experiences of International Students at One Christian School

Science.gov (United States)

Yin, Lishu

2013-01-01

The number of international students flocking to North American private Christian schools has continued to grow. The author examined the overall experiences of 67 international high school students studying at a private Christian school in South Carolina. Their frustrations and struggles with academic and spiritual growth in a new cross-cultural…

Degrees of Co-Creation: An Exploratory Study of Perceptions of International Students' Role in Community Engagement Experiences

Science.gov (United States)

Fleischman, David; Raciti, Maria; Lawley, Meredith

2015-01-01

Increased competition for the international student market has motivated universities to modernize their marketing strategies. Community engagement is an important component of students' international university experience and represents a potential point of competitive advantage. Developing marketing strategies around university-student-community…

The mediating role of internalized racism in the relationship between racist experiences and anxiety symptoms in a Black American sample.

Science.gov (United States)

Graham, Jessica R; West, Lindsey M; Martinez, Jennifer; Roemer, Lizabeth

2016-07-01

The current study explores the potential mediating role of internalized racism in the relationship between racist experiences and anxiety symptomology in a Black American sample. One hundred and 73 Black American participants, between 18 and 62 years of age, completed a questionnaire packet containing measures of anxious arousal and stress symptoms, internalized racism, and experiences of racist events. Results indicated that internalized racism mediated the relationship between past-year frequency of racist events and anxious arousal as well as past-year frequency of racist events and stress symptoms. Internalized racism may be 1 mechanism that underlies the relationship between racism and anxious symptomology for Black Americans. These preliminary findings suggest that internalized racism may be an avenue through which clinicians can target the anxiety elicited by racist experiences. The clinical implications of these findings and future research directions are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Internal monitoring of GBTx emulator using IPbus for CBM experiment

Science.gov (United States)

Mandal, Swagata; Zabolotny, Wojciech; Sau, Suman; Chkrabarti, Amlan; Saini, Jogender; Chattopadhyay, Subhasis; Pal, Sushanta Kumar

2015-09-01

The Compressed Baryonic Matter (CBM) experiment is a part of the Facility for Antiproton and Ion Research (FAIR) in Darmstadt at GSI. In CBM experiment a precisely time synchronized fault tolerant self-triggered electronics is required for Data Acquisition (DAQ) system in CBM experiments which can support high data rate (up to several TB/s). As a part of the implementation of the DAQ system of Muon Chamber (MUCH) which is one of the important detectors in CBM experiment, a FPGA based Gigabit Transceiver (GBTx) emulator is implemented. Readout chain for MUCH consists of XYTER chips (Front end electronics) which will be directly connected to detector, GBTx emulator, Data Processing Board (DPB) and First level event selector board (FLIB) with backend software interface. GBTx emulator will be connected with the XYTER emulator through LVDS (Low Voltage Differential Signalling) line in the front end and in the back end it is connected with DPB through 4.8 Gbps optical link. IPBus over Ethernet is used for internal monitoring of the registers within the GBTx. In IPbus implementation User Datagram Protocol (UDP) stack is used in transport layer of OSI model so that GBTx can be controlled remotely. A Python script is used at computer side to drive IPbus controller.

Experience of the international network in radiation protection

International Nuclear Information System (INIS)

Medina Gironzini, Eduardo

2008-01-01

With the aim of exchanging information on various subjects about radiation protection and designing a site where the members can send and receive information on courses, scientific activities, articles, technical opinions, commentaries and everything that promotes the communication, collaboration and integration, the 15th March 2002 the networking: 'radioproteccion' is created with 11 persons from 11 countries. The number of members had been increased. By the first month it had 117 members and by the end of the year 2002 it had already 179 members, 315 messages were send by then. By December 2007, there were 726 members from 28 countries mainly from Latin America: Argentina, Brazil, Bolivia, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Uruguay and Venezuela. There were also members from Austria, Canada, France, Israel, Italy, Portugal, Spain, Sweden, United Kingdom and United States. There have been distributed 2049 messages about Congress, courses and activities on national and international radiation protection and related issues which initially were in Latin American and the Caribbean. This has allowed diverse specialists that work in different themes to interchange experiences and information about subjects of common interest. This objective is the continuation of the spreading of activities that since 1991 and for 10 consecutive years had been made through the Bulletin 'Proteccion Radiologica', from which 65000 samples were published and distributed to specialists from 40 countries thanks to the support of the International Atomic Energy Agency (IAEA) and the Pan-American Health Organization (PAHO). This idea is complemented by the Web: www.radioproteccion.org. Interesting topics have been discussed in the network for example: Pregnancy and medical radiation, emergency response, occupational exposure, radiation protection responsibilities, lessons learned from accidental

Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS)

Science.gov (United States)

Gasbarre, Joseph; Walker, Richard; Cisewski, Michael; Zawodny, Joseph; Cheek, Dianne; Thornton, Brooke

2015-01-01

The Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) mission will extend the SAGE data record from the ideal vantage point of the International Space Station (ISS). The ISS orbital inclination is ideal for SAGE measurements providing coverage between 70 deg north and 70 deg south latitude. The SAGE data record includes an extensively validated data set including aerosol optical depth data dating to the Stratospheric Aerosol Measurement (SAM) experiments in 1975 and 1978 and stratospheric ozone profile data dating to the Stratospheric Aerosol and Gas Experiment (SAGE) in 1979. These and subsequent data records, notably from the SAGE II experiment launched on the Earth Radiation Budget Satellite in 1984 and the SAGE III experiment launched on the Russian Meteor-3M satellite in 2001, have supported a robust, long-term assessment of key atmospheric constituents. These scientific measurements provide the basis for the analysis of five of the nine critical constituents (aerosols, ozone (O3), nitrogen dioxide (NO2), water vapor (H2O), and air density using O2) identified in the U.S. National Plan for Stratospheric Monitoring. SAGE III on ISS was originally scheduled to fly on the ISS in the same timeframe as the Meteor-3M mission, but was postponed due to delays in ISS construction. The project was re-established in 2009.

INTEGRAL BENCHMARKS AVAILABLE THROUGH THE INTERNATIONAL REACTOR PHYSICS EXPERIMENT EVALUATION PROJECT AND THE INTERNATIONAL CRITICALITY SAFETY BENCHMARK EVALUATION PROJECT

Energy Technology Data Exchange (ETDEWEB)

J. Blair Briggs; Lori Scott; Enrico Sartori; Yolanda Rugama

2008-09-01

Interest in high-quality integral benchmark data is increasing as efforts to quantify and reduce calculational uncertainties accelerate to meet the demands of next generation reactor and advanced fuel cycle concepts. The International Reactor Physics Experiment Evaluation Project (IRPhEP) and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) continue to expand their efforts and broaden their scope to identify, evaluate, and provide integral benchmark data for method and data validation. Benchmark model specifications provided by these two projects are used heavily by the international reactor physics, nuclear data, and criticality safety communities. Thus far, 14 countries have contributed to the IRPhEP, and 20 have contributed to the ICSBEP. The status of the IRPhEP and ICSBEP is discussed in this paper, and the future of the two projects is outlined and discussed. Selected benchmarks that have been added to the IRPhEP and ICSBEP handbooks since PHYSOR’06 are highlighted, and the future of the two projects is discussed.

INTEGRAL BENCHMARKS AVAILABLE THROUGH THE INTERNATIONAL REACTOR PHYSICS EXPERIMENT EVALUATION PROJECT AND THE INTERNATIONAL CRITICALITY SAFETY BENCHMARK EVALUATION PROJECT

International Nuclear Information System (INIS)

J. Blair Briggs; Lori Scott; Enrico Sartori; Yolanda Rugama

2008-01-01

Interest in high-quality integral benchmark data is increasing as efforts to quantify and reduce calculational uncertainties accelerate to meet the demands of next generation reactor and advanced fuel cycle concepts. The International Reactor Physics Experiment Evaluation Project (IRPhEP) and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) continue to expand their efforts and broaden their scope to identify, evaluate, and provide integral benchmark data for method and data validation. Benchmark model specifications provided by these two projects are used heavily by the international reactor physics, nuclear data, and criticality safety communities. Thus far, 14 countries have contributed to the IRPhEP, and 20 have contributed to the ICSBEP. The status of the IRPhEP and ICSBEP is discussed in this paper, and the future of the two projects is outlined and discussed. Selected benchmarks that have been added to the IRPhEP and ICSBEP handbooks since PHYSOR-06 are highlighted, and the future of the two projects is discussed

Prospects of implementation of "Basel III" international standards for domestic banks based on international experience

Directory of Open Access Journals (Sweden)

Baha Oksana

2016-04-01

Full Text Available This article summarizes the main requirements of the "Basel III" new standards in the context of banks capital regulation and identifies prospects for implementation of domestic banks based on analysis of international experience. The urgency of the problem is formulated in the need to restore the stability of the banking system of Ukraine with the new standards, which purpose is to increase the stability of banks and to protect the rights of financial services consumers. The main threats faced by the banking systems of developed countries and possible for the Ukrainian financial system were determined. The ways of achieving maximum benefits of new banking reform introduction were proposed.

Segmentation of microcystic macular edema in Cirrus OCT scans with an exploratory longitudinal study

Science.gov (United States)

Swingle, Emily K.; Lang, Andrew; Carass, Aaron; Al-Louzi, Omar; Saidha, Shiv; Prince, Jerry L.; Calabresi, Peter A.

2015-03-01

Microcystic macular edema (MME) is a term used to describe pseudocystic spaces in the inner nuclear layer (INL) of the human retina. It has been noted in multiple sclerosis (MS) as well as a variety of other diseases. The processes that lead to MME formation and their change over time have yet to be explained sufficiently. The low rate at which MME occurs within such diverse patient groups makes the identification and consistent quantification of this pathology important for developing patient-specific prognoses. MME is observed in optical coherence tomography (OCT) scans of the retina as changes in light reflectivity in a pattern suggestive of fluid accumulations called pseudocysts. Pseudocysts can be readily identified in higher signal-to-noise ratio (SNR) images, however pseudocysts can be indistinguishable from noise in lower SNR scans. In this work, we expand upon our earlier MME identification methods on Spectralis OCT scans to handle lower quality Cirrus OCT scans. Our approach uses a random forest classifier, trained on manual segmentation of ten subjects, to automatically detect MME. The algorithm has a true positive rate for MME identification of 0.95 and a Dice score of 0.79. We include a preliminary longitudinal study of three patients over four to five years to explore the longitudinal changes of MME. The patients with relapsing-remitting MS and neuromyelitis optica appear to have dynamic pseudocyst volumes, while the MME volume appears stable in the one patient with primary progressive MS.

The Role of Attachment, Travel Experiences and English Proficiency in International Students' Acculturative Stress and Depressive Symptoms

Science.gov (United States)

Smiljanic, Iskra

2017-01-01

This study examined the relationship between attachment, travel experiences, and English proficiency and international students' acculturative stress and depressive symptoms. A total of 91 graduate international students completed online surveys. Pearson correlations showed that both attachment anxiety and avoidance were positively correlated with…

PANDA experiment and International Standard Problem for passive cooling systems for afterheat removal

International Nuclear Information System (INIS)

Yadigaroglu, G.; Aksan, N.S.

1999-01-01

In the context of OECD/NEA, Paul Scherrer Institut (PSI) is working on an International Standard Problem which is to provide information on the efficiency and use of computer program systems for passive afterheat removal systems. The PANDA test facility of PSI was designed for these investigations. A six-phase PANDA experiment provides a basis for pre-calculation and recalculation of selected phases covering a limited number of system-typical operating states and phenomena. The experiment was specified and carried out in the year under report [de

International Service Learning: Occupational Therapists' Perceptions of Their Experiences in Guatemala

Directory of Open Access Journals (Sweden)

Jason C. Lawson

2017-01-01

Full Text Available The U.S. is fast becoming more culturally diverse, creating a greater need for entry-level occupational therapists to be culturally competent. In order to increase students’ cultural competence, there is a growing support for international service learning (ISL. The purpose of this qualitative research study was to explore the perspectives of occupational therapy practitioners who engaged in ISL as occupational therapy students. Interviews were conducted with nine practicing occupational therapists, all of whom graduated from the same occupational therapy program in the U.S. and participated in an ISL experience in Guatemala. Phenomenological methods were used to analyze the transcribed interviews for codes, categories, and themes. The three themes that emerged were: Participants reported encountering many new experiences that led to experiencing a variety of emotions, their experiences in the Guatemalan culture further contributed to a deeper level of understanding about culture, and all of the participants reported that their ISL experiences allowed them to practice occupational therapy skills and interventions with limited resources, which facilitated creativity and resourcefulness. The findings of this study support that completing ISL as students contributes to occupational therapists’ personal and professional lives and offers a glimpse of potential long-term effects of completing an ISL experience.

International Transfer Pricing Regulation: Nigerian Experience ...

African Journals Online (AJOL)

Multinational enterprises (MNEs), as any other international business concern, have among other objectives, the reduction of foreign exchange risk, duties or tariffs, foreign and domestic taxes, which ultimately maximise the enterprises profitability. The use of international transfer pricing strategy by MNEs remains on the ...

International Reactor Physics Experiment Evaluation (IRPhE) Project. IRPhE Handbook - 2017 edition

International Nuclear Information System (INIS)

2017-01-01

The International Reactor Physics Evaluation (IRPhE) Project was initiated as a pilot in 1999 by the Nuclear Energy Agency (NEA) Nuclear Science Committee (NSC). The project was endorsed as an official activity of the NSC in June 2003. While the NEA co-ordinates and administers the IRPhE Project at the international level, each participating country is responsible for the administration, technical direction and priorities of the project within their respective countries. The information and data included in this handbook are available to NEA member countries, to all contributing countries and to others on a case-by-case basis. The IRPhE Project is patterned after the International Criticality Safety Benchmark Evaluation Project (ICSBEP). It closely co-ordinates with the ICSBEP to avoid duplication of efforts and publication of conflicting information. Some benchmark data are applicable to both nuclear criticality safety and reactor physics technology. Some have already been evaluated and published by the ICSBEP, but have been extended to include other types of measurements in addition to the critical configuration. Through this effort, the IRPhE Project will be able to 1) consolidate and preserve the existing worldwide information base; 2) retrieve lost data; 3) identify areas where more data are needed; 4) draw upon the resources of the international reactor physics community to help fill knowledge gaps; 5) identify discrepancies between calculations and experiments due to deficiencies in reported experimental data, cross-section data, cross-section processing codes and neutronics codes; 6) eliminate a large amount of redundant research and processing of reactor physics experiment data, and 7) improve future experimental planning, execution and reporting. This handbook contains reactor physics benchmark specifications that have been derived from experiments performed at nuclear facilities around the world. The benchmark specifications are intended for use by

Irradiation experiments on materials for core internals, pressure vessel and fuel cladding

Energy Technology Data Exchange (ETDEWEB)

Tsukada, Takashi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-03-01

Materials degradation due to the aging phenomena is one of the key issues for the life assessment and extension of the light water reactors (LWRs). This presentation introduces JAERI`s activities in the field of LWR material researches which utilize the research and testing reactors for irradiation experiments. The activities are including the material studies for the core internals, pressure vessel and fuel cladding. These materials are exposed to the neutron/gamma radiation and high temperature water environments so that it is worth reviewing their degradation phenomena as the continuum. Three topics are presented; For the core internal materials, the irradiation assisted stress corrosion cracking (IASCC) of austenitic stainless steels is the present major concern. At JAERI the effects of alloying elements on IASCC have been investigated through the post-irradiation stress corrosion cracking tests in high-temperature water. The radiation embrittlement of pressure vessel steels is still a significant issue for LWR safety, and at JAERI some factors affecting the embrittlement behavior such as a dose rate have been investigated. Waterside corrosion of Zircaloy fuel cladding is one of the limiting factors in fuel rod performance and an in-situ measurement of the corrosion rate in high-temperature water was performed in JMTR. To improve the reliability of experiments and to extent the applicability of experimental techniques, a mutual utilization of the technical achievements in those irradiation experiments is desired. (author)

Analysis of cirrus cloud spectral signatures in the far infrared

International Nuclear Information System (INIS)

Maestri, T.; Rizzi, R.; Tosi, E.; Veglio, P.; Palchetti, L.; Bianchini, G.; Di Girolamo, P.; Masiello, G.; Serio, C.; Summa, D.

2014-01-01

This paper analyses high spectral resolution downwelling radiance measurements in the far infrared in the presence of cirrus clouds taken by the REFIR-PAD interferometer, deployed at 3500 m above the sea level at the Testa Grigia station (Italy), during the Earth COoling by WAter vapouR emission (ECOWAR) campaign. Atmospheric state and cloud geometry are characterised by the co-located millimeter-wave spectrometer GBMS and by radiosonde profile data, an interferometer (I-BEST) and a Raman lidar system deployed at a nearby location (Cervinia). Cloud optical depth and effective diameter are retrieved from REFIR-PAD data using a limited number of channels in the 820–960 cm −1 interval. The retrieved cloud parameters are the input data for simulations covering the 250–1100 cm −1 band in order to test our ability to reproduce the REFIR-PAD spectra in the presence of ice clouds. Inverse and forward simulations are based on the same radiative transfer code. A priori information concerning cloud ice vertical distribution is used to better constrain the simulation scheme and an analysis of the degree of approximation of the phase function within the radiative transfer codes is performed to define the accuracy of computations. Simulation-data residuals over the REFIR-PAD spectral interval show an excellent agreement in the window region, but values are larger than total measurement uncertainties in the far infrared. Possible causes are investigated. It is shown that the uncertainties related to the water vapour and temperature profiles are of the same order as the sensitivity to the a priori assumption on particle habits for an up-looking configuration. In case of a down-looking configuration, errors due to possible incorrect description of the water vapour profile would be drastically reduced. - Highlights: • We analyze down-welling spectral radiances in the far infrared (FIR) spectrum. • Discuss the scattering in the fir and the ice crystals phase function

Academic performance and personal experience of local, international, and collaborative exchange students enrolled in an Australian pharmacy program.

Science.gov (United States)

Davey, Andrew K; Grant, Gary D; Anoopkumar-Dukie, Shailendra

2013-09-12

To assess the academic performance and experiences of local, international, and collaborative exchange students enrolled in a 4-year Australian bachelor of pharmacy degree program. Survey instruments exploring the demographics, background, and academic and cultural experiences of students during the program were administered in 2005 to students in all 4 years. Additionally, grades from each semester of the program for students (406 local, 70 international, 155 exchange) who graduated between 2002 and 2006 were analyzed retrospectively. The main differences found in the survey responses among the 3 groups were in students' motivations for choosing the degree program and school, with international and collaborative exchange students having put more thought into these decisions than local students. The average grades over the duration of the program were similar in all 3 demographic groups. However, local students slightly outperformed international students, particularly at the start of the year, whereas collaborative exchange students' grades mirrored those of local students during the 2 years prior to leaving their home country of Malaysia but more closely mirrored those of international students in the final 2 years after arriving on campus in Australia. Despite differences in academic backgrounds and culture, international and exchange students can perform well compared to local students in a bachelor of pharmacy program and were actually more satisfied than local students with the overall experience. Studying in a foreign country can negatively influence academic grades to a small extent and this is probably related to adjusting to the new environment.

International Student Destination Choice: The Influence of Home Campus Experience on the Decision to Consider Branch Campuses

Science.gov (United States)

Wilkins, Stephen; Huisman, Jeroen

2011-01-01

Previous research has found that the country and institution choices of international students are greatly influenced by recommendations they receive from others who have experience of undertaking higher education overseas. For Western universities, it is of utmost importance to satisfy their international students, who can then encourage the next…

International experience in addressing combined exposures: Increasing the efficiency of assessment

International Nuclear Information System (INIS)

Meek, M.E.

2013-01-01

More efficient methodology for assessing the impact of combined exposures to multiple chemicals has been considered in a project of the World Health Organization (WHO) International Programme on Chemical Safety (IPCS). Recommendations regarding terminology and the status of development of the framework, its content, review and application are described. Evolving experience in its application is illustrated by example (polybrominated diphenyls) with special emphasis on the critical content of problem formulation, the role of predictive tools in grouping of chemicals for consideration and the importance of explicit delineation of relative uncertainty and sensitivity for tiered assessment. Priorities in increasing the efficiency of risk assessment not only for combined exposures, but more generally based on experience acquired in developing the framework and its application in case studies are identified and recommendations included

The experiences of internationally educated nurses in the southeastern United States of America.

Science.gov (United States)

Wheeler, R M; Foster, J W; Hepburn, K W

2013-09-01

US healthcare facilities have addressed nursing shortages in part by recruiting internationally educated nurses (IENs), and studies suggest IENs may make up a significant percentage of the nursing workforce in urban hospitals. Despite the economic recession of 2008-2012, international nurse migration is expected to continue. Little is known about IENs in the southeastern USA, and no studies have compared their perspectives to those of their US counterparts. The purpose of this study was to gain a deeper understanding about the experiences of IENs compared to those of US registered nurses (RNs) practising in two urban hospitals in southeastern USA. This study involved two rounds of semi-structured interviews of 82 IENs and US RNs. Interviews focused on themes relating to education, barriers to practice, intent to stay in nursing and IENs' migration experiences. Most IENs interviewed migrated to the USA after 1990 to join their family and do not plan to return to their home countries to practise. Most IENs initially received their Associate Degree in Nursing; many have obtained their Bachelor of Science in Nursing degree. IENs and newly licensed US RNs faced similar barriers when they began practising in the USA, but IENs faced additional challenges adjusting to the attitudes of US patients, the perceived lack of respect for nurses and delivering total patient care. IENs would benefit from orientation regarding the cultural differences in the USA. In other ways, their challenges are similar to those of US RNs; policies regarding education, recruitment and retention could target both groups together. © 2013 The Authors. International Nursing Review © 2013 International Council of Nurses.

International dosimetry experiment on the zero power pile of the Boris Kidric Institute at Vinca (Yugoslavia) (1961)

International Nuclear Information System (INIS)

Weill, J.; Furet, J.; Baillet, J.; Donvez, G.; Duchene, J.; Gras, R.; Mercier, R.; Chenouard, J.; Lecomte, J.

1961-01-01

On the occasion of the international dosimetry experiment on the zero power pile of the Yugoslavian Atomic Energy Centre at Vinca, the Commissariat a l'energie Atomique had agreed to prepare the measurement and security equipment and see to the manipulation of the heavy water, and in addition was responsible for the operation and the starting up of the pile during the experiment. The measurement and security apparatus, developed at Saclay and installed on the pile for low and high pressure runs, is listed, together with the safety equipment added near the control room. The various operations and manipulations carried out on the pile are described: filling with heavy water, starting up, determination of the critical level, testing the efficiency of the rods, operating the pile during the experiments. By operating to a carefully planned schedule, the experiments were, finished before the date fixed by the International Atomic Agency. (authors) [fr

Nursing student voices: reflections on an international service learning experience.

Science.gov (United States)

Main, E Eve; Garrett-Wright, Dawn; Kerby, Molly

2013-01-01

For the past decade participation in service and experiential learning in higher education has increased. The purpose of this study was to explore the lived experience of BSN and MSN students participating in a multidisciplinary service-learning course in a rural, underserved village in Belize. Researchers analyzed student journals utilizing qualitative data analysis techniques. There were eight consistent themes found in the student journals. The findings indicate that international service learning opportunities increase students' awareness of their place in a global society and the potential contribution they can make in society. For the past decade, service and experiential learning in higher education, including nursing education, has become increasingly important. Simply put, service and experiential learning combine community service activities with a student's academic study for the sole purpose of enriching the academic experience. As faculty, we feel the goal of baccalaureate and graduate nursing education is to produce an educated professional who will become a responsible citizen.

Emotional Problems and Victimisation among Youth with National and International Migration Experience Living in Austria and Turkey

Science.gov (United States)

Strohmeier, Dagmar; Dogan, Aysun

2012-01-01

Young people with international migration experiences constitute an increasing proportion of the population in many European countries. In Austria, a substantial proportion of these international migrants come from Turkey. In Turkey, many adolescents are national migrants, having moved from the eastern part to the western part of the country. This…

The Secret Lives of Undergraduate International Business Students: An Analysis of Cross-Cultural Experience in Multinational Corporations.

Science.gov (United States)

Pederson de Castaneda, Viann

This study involved students majoring in business/economics and foreign language in an international business program. The students were participants in a semester-long international experience where students were integrated into a host university to learn about management, economics, and marketing from professors abroad, and in an internship in a…

Cirrus clouds properties derived from polarized micro pulse lidar (p-mpl) observations at the atmospheric observatory `el arenosillo' (sw iberian peninsula): a case study for radiative implications

Science.gov (United States)

Águila, Ana del; Gómez, Laura; Vilaplana, José Manuel; Sorribas, Mar; Córdoba-Jabonero, Carmen

2018-04-01

Cirrus (Ci) clouds are involved in Climate Change concerns since they affect the radiative balance of the atmosphere. Recently, a polarized Micro Pulse Lidar (P-MPL), standard system within NASA/MPLNET has been deployed at the INTA/Atmospheric Observatory `El Arenosillo' (ARN), located in the SW Iberian Peninsula. Hence, the INTA/P-MPL system is used for Ci detection over that station for the first time. Radiative effects of a Ci case observed over ARN are examined, as reference for future long-term Ci observations. Optical and macrophysical properties are retrieved, and used for radiative transfer simulations. Data are compared to the measured surface radiation levels and all-sky images simultaneously performed at the ARN station.

The Influence of Experience and Cognitive Style on International Entrepreneurial Intentions: The Contribution of Academic Education in this Relation

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Sommer, Lutz

2013-01-01

Introduction: The paper at hand examines the influence of Cognitive Style (CS) and International Experience (IE) on International Entrepreneurial Self-Efficacy (IESE) and International Entrepreneurial Intention (IEI) as well as the role of Academic Education (AE) in this context. Method: Based on a survey that was conducted among 111 students the…

A qualitative investigation of the cultural adjustment experiences of Asian international college women.

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Constantine, Madonna G; Kindaichi, Mai; Okazaki, Sumie; Gainor, Kathy A; Baden, Amanda L

2005-05-01

This qualitative study explored the cultural adjustment experiences of 15 Asian Indian, Japanese, Korean, and Vietnamese international college women through semistructured interviews. By using consensual qualitative research methodology (C. E. Hill, B. J. Thompson, & E. N. Williams, 1997), 6 primary domains or themes related to these women's cultural adjustment experiences were identified via data analysis: their feelings and thoughts about living in the United States, perceived differences between their country of origin and the United States, their English language acquisition and use, their prejudicial or discriminatory experiences in the United States, their peer and family networks, and their strategies for coping with cultural adjustment problems. Implications of the findings for mental health practice are discussed. Copyright (c) 2005 APA, all rights reserved.

Educational Experiences Associated with International Students' Learning, Development, and Positive Perceptions of Campus Climate

Science.gov (United States)

Glass, Chris R.

2012-01-01

This research project uses the constructive-developmental tradition, in the self-authorship framework of intercultural maturity (King & Baxter Magolda, 2005), to examine the extent to which 12 specific educational experiences may be associated with international undergraduates' learning, development, and perception of campus climate. The study…

Complex licences: a decade of experience with internal inspections

International Nuclear Information System (INIS)

Boersma, Hielke Freerk; Bunskoeke, Erik J.

2008-01-01

Full text: In 2008 the University of Groningen has ten years of experience with the system of complex broad licences. This system was introduced on a larger scale in the Netherlands in the last decade of the twentieth century. Its main characteristics are an internal radiation protection organization and a system of internal permits or licences for all applications of ionizing radiation along with periodical inspections. Since 1998/9 we yearly conduct inspections of all users of ionizing radiation within the University of Groningen. In our presentation we will discuss the general scheme for these inspections as well as the development of its results over the past decade. Following a period of habituation the last few years show a adequate and continuous level of radiation protection. It is also concluded that continuation of the inspection projects is a prerequisite to preserve this situation. Combined with the inspection project of 2007 an informal study of the 'customer'-satisfaction with respect to various aspects of the radiation protection organization was performed. Our data were collected using a questionnaire filled out by local radiation safety officers. In this contribution detailed results of this investigation will be presented. Preliminary results show that the overall appreciation of the radiation protection organization is qualified as 'good'. (author)

Analysis of satellite data for sensor improvement (detection of severe storms from space)

Science.gov (United States)

Fujita, T. T.

1984-01-01

Stereo photography of clouds over southeast Asia was obtained using NOAA-7 and the Japanese GMS. Due to the breakdown of GMS2, GMS1, which had been retired, is being used as the replacement satellite. The launch of GMS should permit the US-Japan stereo experiment to be reactivated. The Lear jet experiment based at Grand Island, Nebraska was successful and provided data on the Redwood Falls clouds & Grand Island thunderstorm; an anvil-top cirrus deck; a circular thunderstorm; and jumping cirrus. The IR temperature field of the thunderstorm which induced the Andrews AFB microburst was analyzed with 1 C accuracy. The microburst and severe thunderstorm project is being planned.

The experience of being a member of the Student International Community of Practice: a collaborative reflection

Directory of Open Access Journals (Sweden)

Brighide M. Lynch

2015-05-01

Full Text Available Background: In 2010 a community of practice was set up for and by doctoral students engaged in person-centred and practitioner research. After three years, this community became part of a larger international community of practice. Aims and objectives: Captured under the stanzas of a poem and supported by the literature, this paper uses member narratives and creative expressions in a critical reflection on the experience of being a member of the Student International Community of Practice. Conclusions: Membership in the community of practice was experienced as beneficial, providing both support and challenge to enrich the doctoral students’ development as person-centred researchers. Retaining connectivity across an international landscape and finding effective ways to integrate new members into the community presented the greatest challenges. Implications for practice development: • The theoretical foundation and experiential knowledge could assist others considering support structures for the development of person-centred practices • Shared learning and co-creation of knowledge add value to the experience of being a doctoral researcher • Membership fluctuations present challenges to continuity of learning and the maintenance of a safe space with communities of practice. Such fluctuations, however, create chances for community members to experience diverse roles within the group and encourage explicit attention to person-centredness

International Handbook of Evaluated Criticality Safety Benchmark Experiments - ICSBEP (DVD), Version 2013

International Nuclear Information System (INIS)

2013-01-01

The Criticality Safety Benchmark Evaluation Project (CSBEP) was initiated in October of 1992 by the United States Department of Energy. The project quickly became an international effort as scientists from other interested countries became involved. The International Criticality Safety Benchmark Evaluation Project (ICSBEP) became an official activity of the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (NEA) in 1995. This handbook contains criticality safety benchmark specifications that have been derived from experiments performed at various nuclear critical experiment facilities around the world. The benchmark specifications are intended for use by criticality safety engineers to validate calculational techniques used to establish minimum subcritical margins for operations with fissile material and to determine criticality alarm requirement and placement. Many of the specifications are also useful for nuclear data testing. Example calculations are presented; however, these calculations do not constitute a validation of the codes or cross section data. The evaluated criticality safety benchmark data are given in nine volumes. These volumes span nearly 66,000 pages and contain 558 evaluations with benchmark specifications for 4,798 critical, near critical or subcritical configurations, 24 criticality alarm placement/shielding configurations with multiple dose points for each and 200 configurations that have been categorised as fundamental physics measurements that are relevant to criticality safety applications. New to the Handbook are benchmark specifications for Critical, Bare, HEU(93.2)- Metal Sphere experiments referred to as ORSphere that were performed by a team of experimenters at Oak Ridge National Laboratory in the early 1970's. A photograph of this assembly is shown on the front cover

International Students from Melbourne Describing Their Cross-Cultural Transitions Experiences: Culture Shock, Social Interaction, and Friendship Development

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Belford, Nish

2017-01-01

Drawing from a study that explored how international students experience cross-cultural transitions after living and studying in Melbourne for a few years, this paper, in particular, examines the participants' experiences with culture shock, social interaction, and friendship development. The findings include narratives of their personal stories…

Tax and Fiscal Policies for Promotion of Industrial EnergyEfficiency: A Survey of International Experience

Energy Technology Data Exchange (ETDEWEB)

Price, Lynn; Galitsky, Christina; Sinton, Jonathan; Worrell,Ernst; Graus, Wina

2005-09-15

The Energy Foundation's China Sustainable Energy Program (CSEP) has undertaken a major project investigating fiscal and tax policy options for stimulating energy efficiency and renewable energy development in China. This report, which is part of the sectoral sub-project studies on energy efficiency in industry, surveys international experience with tax and fiscal policies directed toward increasing investments in energy efficiency in the industrial sector. The report begins with an overview of tax and fiscal policies, including descriptions and evaluations of programs that use energy or energy-related carbon dioxide (CO2) taxes, pollution levies, public benefit charges, grants or subsidies, subsidized audits, loans, tax relief for specific technologies, and tax relief as part of an energy or greenhouse gas (GHG) emission tax or agreement scheme. Following the discussion of these individual policies, the report reviews experience with integrated programs found in two countries as well as with GHG emissions trading programs. The report concludes with a discussion of the best practices related to international experience with tax and fiscal policies to encourage investment in energy efficiency in industry.

Cultural Demands of the Host-Nation: International Student Experience and the Public Diplomacy Consequences

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Triana, Benjamin

2015-01-01

Traditional approaches for hosting international students tend to focus on classroom achievement rather than on intercultural exchange and cultural immersion. Such approaches lessen the possibility of successful educational experiences which also hinders public diplomacy. Two case studies are presented that reveal how structural changes at a…

Postglobal Teacher Preparation: Border Thinking along the Global South through International Cross-Cultural Experiences

Science.gov (United States)

Rahatzad, Jubin; Sasser, Hannah L.; Phillion, JoAnn; Karimi, Nastaran; Deng, Yuwen; Akiyama, Reiko; Sharma, Suniti

2013-01-01

Preservice teachers' international cross-cultural experiences can provide opportunities for the exploration of epistemic frontiers. In this article we suggest that postglobal teacher preparation take a critically reflective approach that engages preservice teachers in border thinking, which allows for other ways of knowing while studying abroad.…

Assessing the Motivators and Barriers Influencing Undergraduate Students' Choices to Participate in International Experiences

Science.gov (United States)

Bunch, J.C.; Lamm, Alexa J.; Israel, Glenn D.; Edwards, M. Craig

2013-01-01

International experiences (IEs) are becoming one of the most critical elements of an undergraduate student's education to address the knowledge needed to become globally competent. However, student enrollment in IEs has been limited. Agricultural educators can more easily influence students' decisions regarding participation in IEs if they…

The International Heat Stress Genotype Experiment for modeling wheat response to heat: field experiments and AgMIP-Wheat multi-model simulations

NARCIS (Netherlands)

Martre, P.; Reynolds, M.P.; Asseng, S.; Ewert, F.; Alderman, P.D.; Cammarano, D.; Maiorano, Andrea; Ruane, A.C.; Aggarwal, P.K.; Anothai, J.; Supit, I.; Wolf, J.

2017-01-01

The data set contains a portion of the International Heat Stress Genotype Experiment (IHSGE) data used in the AgMIP-Wheat project to analyze the uncertainty of 30 wheat crop models and quantify the impact of heat on global wheat yield productivity. It includes two spring wheat cultivars grown during

TANPOPO: Microbe and micrometeoroid capture experiments on International Space Station.

Science.gov (United States)

Yamagishi, Akihiko; Kobayashi, Kensei; Yano, Hajime; Yokobori, Shinichi; Hashimoto, Hirofumi; Kawai, Hideyuki; Yamashita, Masamichi

There is a long history of the microbe-collection experiments at high altitude. Microbes have been collected using balloons, aircraft and meteorological rockets from 1936 to 1976. Spore forming fungi and Bacilli, and Micrococci have been isolated in these experiments. It is not clear how high do microbes go up. If the microbes might have been present even at higher altitudes, the fact would endorse the possibility of interplanetary migration of life. TANPOPO, dandelion, is the name of a grass whose seeds with floss are spread by the wind. We propose the analyses of interplanetary migration of microbes, organic compounds and meteoroids on Japan Experimental Module (JEM) of the International Space Station (ISS). Ultra low-density aerogel will be used to capture micrometeoroid and debris. Particles captured by aerogel will be used for several analyses after the initial inspection of the gel and tracks. Careful analysis of the tracks in the aerogel will provide the size and velocity dependence of debris flux. The particles will be analyzed for mineralogical, organic and microbiological characteristics. Aerogels are ready for production in Japan. Aerogels and trays are space proven. All the analytical techniques are ready. The Tanpopo mission was accepted as a candidate experiments on Exposed Facility of ISS-JEM.

Experiences of a support group for interns in the setting of war and political turmoil.

Science.gov (United States)

El Jamil, Fatima; Hamadeh, Ghassan N; Osman, Hibah

2007-10-01

Intern support groups have been instituted in many residency programs to improve resident well-being. In this article, we discuss the themes that emerged in intern support group meetings in a family medicine program operating in a setting of war and political instability. We held support groups, led by a family physician and a psychologist, that met monthly. Participants were residents in the family medicine program at the American University of Beirut. These residents began their training days after the commencement of the 34-day war between Israel and Hizbollah in 2006. Themes and issues discussed by the residents were noted and are reported in this article. We found that despite the stressors of the political situation, our interns focused on the usual stress of internship, such as the difficulties of functioning as interns in other departments and dealing with the time demands of internship as their main sources of stress at the beginning of internship. The stresses associated with the war did not emerge in the group until later in the year. These included tension with patients and political confrontations with staff, as well as personal struggles with the lack of political stability and depressed mood. This paper serves to share our experience and highlight some areas of concern that residents experience when training in a country or region that is at war.

Simultaneous retrieval of water vapour, temperature and cirrus clouds properties from measurements of far infrared spectral radiance over the Antarctic Plateau

Science.gov (United States)

Di Natale, Gianluca; Palchetti, Luca; Bianchini, Giovanni; Del Guasta, Massimo

2017-03-01

The possibility separating the contributions of the atmospheric state and ice clouds by using spectral infrared measurements is a fundamental step to quantifying the cloud effect in climate models. A simultaneous retrieval of cloud and atmospheric parameters from infrared wideband spectra will allow the disentanglement of the spectral interference between these variables. In this paper, we describe the development of a code for the simultaneous retrieval of atmospheric state and ice cloud parameters, and its application to the analysis of the spectral measurements acquired by the Radiation Explorer in the Far Infrared - Prototype for Applications and Development (REFIR-PAD) spectroradiometer, which has been in operation at Concordia Station on the Antarctic Plateau since 2012. The code performs the retrieval with a computational time that is comparable with the instrument acquisition time. Water vapour and temperature profiles and the cloud optical and microphysical properties, such as the generalised effective diameter and the ice water path, are retrieved by exploiting the 230-980 cm-1 spectral band. To simulate atmospheric radiative transfer, the Line-By-Line Radiative Transfer Model (LBLRTM) has been integrated with a specifically developed subroutine based on the δ-Eddington two-stream approximation, whereas the single-scattering properties of cirrus clouds have been derived from a database for hexagonal column habits. In order to detect ice clouds, a backscattering and depolarisation lidar, co-located with REFIR-PAD has been used, allowing us to infer the position and the cloud thickness to be used in the retrieval. A climatology of the vertical profiles of water vapour and temperature has been performed by using the daily radiosounding available at the station at 12:00 UTC. The climatology has been used to build an a priori profile correlation to constrain the fitting procedure. An optimal estimation method with the Levenberg-Marquardt approach has been

In search of an African dining experience: International visitors views on service at V&A Waterfront restaurants in Cape Town

Directory of Open Access Journals (Sweden)

Takawira Windy Mutsago

2011-01-01

Full Text Available Culturalism and ethnicity form integral parts of destination attractions in tourism and hospitality. The article explores the degree of African authenticity expected by international travelers from a dining experiences in restaurants located in a popular tourist hub, the Victoria and Alfred Waterfront in Cape Town. The research reveals that integrating traditional African values and standards to five star dining international standards is difficult and problematic. Consequently international diners seeking authentic African dining experience in popular tourists’ hubs have been disappointed. The paper revealed that the majority 75.3% perceived the dining experience in the V&A Waterfront as just a copy of the Western countries, 19, 2% percent noted some African traits largely diluted by foreign standards and 6, 5% believed it was truly an African dining experience. The article recommends that, for commercial purposes a staged African experience be created using such strategies as manipulating the architecture, the music, interior décor, staff uniforms and anything that immediately identifies with Africa or South Africa on a more local level.

Overview of the 2014 Edition of the International Handbook of Evaluated Reactor Physics Benchmark Experiments (IRPhEP Handbook)

Energy Technology Data Exchange (ETDEWEB)

John D. Bess; J. Blair Briggs; Jim Gulliford; Ian Hill

2014-10-01

The International Reactor Physics Experiment Evaluation Project (IRPhEP) is a widely recognized world class program. The work of the IRPhEP is documented in the International Handbook of Evaluated Reactor Physics Benchmark Experiments (IRPhEP Handbook). Integral data from the IRPhEP Handbook is used by reactor safety and design, nuclear data, criticality safety, and analytical methods development specialists, worldwide, to perform necessary validations of their calculational techniques. The IRPhEP Handbook is among the most frequently quoted reference in the nuclear industry and is expected to be a valuable resource for future decades.

First childbirth experience of international marriage migrant women in South Korea.

Science.gov (United States)

Chu, Min Sun; Park, Minna; Kim, Jung A

2017-08-01

Since the mid-1990s, a large number of foreign women have migrated from developing countries to South Korea by means of international marriages. These nulliparous foreign women may experience more difficulties in pregnancy and childbirth than native Koreans. This study aimed to describe the meaning of the first childbirth experiences of international marriage migrant women marrying Korean men in South Korea. This is a descriptive phenomenological study that included 10 participants using the purposive and snowball sampling in one multicultural support center in Seoul, South Korea. Colaizzi's data analysis method was used to inductively determine themes and formulate meanings. The meanings of first childbirth were categorized into four themes-'coming to a crisis,' 'depending on others,' 'searching for solutions,' and 'strengthening family unity.' Inadequate antenatal care is associated with obstacles such as language barriers, social isolation, lack of knowledge, different midwifery practice and dependent lifestyle. Meanwhile, their children were a source of energy for the women to fulfill their emotional needs and improve family relationships. Childbirth is a life-changing event for these women, in which they face challenges as well as opportunities to develop new coping skills and a new role identity in their family. It is important for healthcare providers and policy makers to identify obstacles and unmet needs to improve maternity care in light of the distinctive challenges of immigrant living in multicultural families. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Analyses of internal tides generation and propagation over a Gaussian ridge in laboratory and numerical experiments

Science.gov (United States)

Dossmann, Yvan; Paci, Alexandre; Auclair, Francis; Floor, Jochem

2010-05-01

Internal tides are suggested to play a major role in the sustaining of the global oceanic circulation [1][5]. Although the exact origin of the energy conversions occurring in stratified fluids is questioned [2], it is clear that the diapycnal energy transfers provided by the energy cascade of internal gravity waves generated at tidal frequencies in regions of steep bathymetry is strongly linked to the general circulation energy balance. Therefore a precise quantification of the energy supply by internal waves is a crucial step in forecasting climate, since it improves our understanding of the underlying physical processes. We focus on an academic case of internal waves generated over an oceanic ridge in a linearly stratified fluid. In order to accurately quantify the diapycnal energy transfers caused by internal waves dynamics, we adopt a complementary approach involving both laboratory and numerical experiments. The laboratory experiments are conducted in a 4m long tank of the CNRM-GAME fluid mechanics laboratory, well known for its large stratified water flume (e.g. Knigge et al [3]). The horizontal oscillation at precisely controlled frequency of a Gaussian ridge immersed in a linearly stratified fluid generates internal gravity waves. The ridge of e-folding width 3.6 cm is 10 cm high and spans 50 cm. We use PIV and Synthetic Schlieren measurement techniques, to retrieve the high resolution velocity and stratification anomaly fields in the 2D vertical plane across the ridge. These experiments allow us to get access to real and exhaustive measurements of a wide range of internal waves regimes by varying the precisely controlled experimental parameters. To complete this work, we carry out some direct numerical simulations with the same parameters (forcing amplitude and frequency, initial stratification, boundary conditions) as the laboratory experiments. The model used is a non-hydrostatic version of the numerical model Symphonie [4]. Our purpose is not only to

"I feel free": Experiences of a dance intervention for adolescent girls with internalizing problems.

Science.gov (United States)

Duberg, Anna; Möller, Margareta; Sunvisson, Helena

2016-01-01

Adolescent girls today suffer from internalizing problems such as somatic symptoms and mental health problems at higher rates compared to those of previous decades, and effective interventions are warranted. The aim of this study was to explore the experiences of participating in an 8-month dance intervention. This qualitative study was embedded in a randomized controlled trial of a dance intervention for adolescent girls with internalizing problems. A total of 112 girls aged 13-18 were included in the study. The dance intervention group comprised 59 girls, 24 of whom were strategically chosen to be interviewed. Data were analyzed using qualitative content analysis with an inductive approach. The experiences of the dance intervention resulted in five generic categories: (1) An Oasis from Stress, which represents the fundamental basis of the intervention; (2) Supportive Togetherness, the setting; (3) Enjoyment and Empowerment, the immediate effect; (4) Finding Acceptance and Trust in Own Ability, the outcome; and (5) Dance as Emotional Expression, the use of the intervention. One main category emerged, Finding Embodied Self-Trust That Opens New Doors, which emphasizes the increased trust in the self and the ability to approach life with a sense of freedom and openness. The central understanding of the adolescent girls' experiences was that the dance intervention enriched and gave access to personal resources. With the non-judgmental atmosphere and supportive togetherness as a safe platform, the enjoyment and empowerment in dancing gave rise to acceptance, trust in ability, and emotional expression. Taken together, this increased self-trust and they discovered a new ability to "claim space." Findings from this study may provide practical information on designing future interventions for adolescent girls with internalizing problems.

Past Expectations, Current Experiences, and Imagined Futures: Narrative Accounts of Chinese International Students in Canada

OpenAIRE

Zhang, Zhihua

2017-01-01

The internationalization of higher education has led to the influx of Chinese international students in Canada. The literature on these students usually addresses the factors that drive them to Canada, their learning experiences, and the impact of the stereotypical constructions of “Chinese learners” on their language learning. But the literature does not connect the current learning experiences of these students to their past back in China and the futures in their imagination. This narrative...

Internal fuel motion as an inherent shutdown mechanism for LMFBR accidents: PINEX-3, PINEX-2, and HUT 5-2A experiments

International Nuclear Information System (INIS)

Ferrell, P.C.; Porten, D.R.; Martin, F.J.

1981-01-01

The PINEX-2 experiment verified the concept of axial internal molten fuel motion within annular fuel, representing an inherent shutdown mechanism for hypothetical transient overpower excursions on the order of 5$/s. The PINEX-3 experiment, simulating a 50 cents/s transient overpower, showed that limitations on the effectiveness of fuel motion may arise from freezing of the fuel and blockage of the internal movement. Analysis of these experiments was performed to assess the physical processes that dominate fuel relocation potential and to apply them to prototypic LMFBR pin conditions. Results indicate that internal fuel motion should be reliable as a shutdown mechanism in LMFBR's for a range of reactivity insertion rates beyond presently available experimental data

Learning for Entrepreneurship in Heterogeneous Groups: Experiences From an International, Interdisciplinary Higher Education Student Program

NARCIS (Netherlands)

Lans, T.; Popov, V.; Oganisjana, K.; Täks, M.

2013-01-01

Although entrepreneurship education (EE) has gained popularity internationally, empirical work is scarce on the factors which influence the underlying learning process. This article presents the experiences of a European summer school where factors which contribute to entrepreneurial learning in

Assessment of a Brief Handoff Skills Workshop for Incoming Interns: Do past Handoff Experiences Impact Training Outcomes?

Directory of Open Access Journals (Sweden)

Christopher J. Smith

2015-01-01

Full Text Available Background Patient care handoffs are a core professional activity that incoming interns are expected to perform without direct supervision upon starting residency, yet training in medical schools is inconsistent. Objective To implement a brief handoff communication workshop for incoming interns and determine whether learner-level determinants were associated with differences in training outcomes. Methods We conducted a one-hour interactive handoff skills workshop for all incoming interns at a Midwestern academic medical center. We performed paired pre/post-intervention assessments of participants' attitudes and ability to perform representative handoff skills. The results were analyzed in aggregate and based upon participants' prior handoff experiences using Wilcoxon signed-rank test. Results Ninety-nine of 108 interns (91.7% completed both pre- and post-surveys. There was significant improvement in all 10 attitude-based questions ( P ≤ 0.014 for all and on the skills assessment (1.07 vs 2.16 on 0–4 point scale, SD 1.25, P ≤ 0.001. Results remained significant regardless of prior training, number of handoffs observed, number of handoffs performed, medical school, or residency discipline. Conclusion A brief interactive workshop for incoming interns can improve participants' confidence and performance of basic handoff skills, regardless of previous training or experience.

Monitoring stress among internal medicine residents: an experience-driven, practical and short measure.

Science.gov (United States)

Myszkowski, Nils; Villoing, Barbara; Zenasni, Franck; Jaury, Philippe; Boujut, Emilie

2017-07-01

Residents experience severely high levels of stress, depression and burnout, leading to perceived medical errors, as well as to symptoms of impairment, such as chronic anger, cognitive impairment, suicidal behavior and substance abuse. Because research has not yet provided a psychometrically robust population-specific tool to measure the level of stress of medicine residents, we aimed at building and validating such a measure. Using an inductive scale development approach, a short, pragmatic measure was built, based on the interviews of 17 medicine residents. The Internal Medicine Residency Stress Scale (IMRSS) was then administered in a sample of 259 internal medicine residents (199 females, 60 males, M Age  = 25.6) along with the Hospital Anxiety and Depression Scale, Maslach Burnout Inventory, Satisfaction With Life Scale and Ways of Coping Checklist. The IMRSS showed satisfactory internal reliability (Cronbach's α = .86), adequate structural validity - studied through Confirmatory Factor Analysis (χ 2 /df = 2.51, CFI = .94; SRMR = .037, RMSEA = .076) - and good criterion validity - the IMRSS was notably strongly correlated with emotional exhaustion (r = .64; p is recommended to quickly and frequently assess and monitor stress among internal medicine residents.

Effect of a Community-Based Service Learning Experience in Geriatrics on Internal Medicine Residents and Community Participants.

Science.gov (United States)

Miller, Rachel K; Michener, Jennifer; Yang, Phyllis; Goldstein, Karen; Groce-Martin, Jennine; True, Gala; Johnson, Jerry

2017-09-01

Community-based service learning (CBSL) provides an opportunity to teach internal medicine residents the social context of aging and clinical concepts. The objectives of the current study were to demonstrate the feasibility of a CBSL program targeting internal medicine residents and to assess its effect on medical residents and community participants. internal medicine residents participated in a CBSL experience for half a day during ambulatory blocks from 2011 to 2014. Residents attended a senior housing unit or center, delivered a presentation about a geriatric health topic, toured the facility, and received information about local older adult resources. Residents evaluated the experience. Postgraduate Year 3 internal medicine residents (n = 71) delivered 64 sessions. Residents felt that the experience increased their ability to communicate effectively with older adults (mean 3.91 ± 0.73 on a Likert scale with 5 = strongly agree), increased their knowledge of resources (4.09 ± 1.01), expanded their knowledge of a health topic pertinent to aging (3.48 ± 1.09), and contributed to their capacity to evaluate and care for older adults (3.84 ± 0.67). Free-text responses demonstrated that residents thought that this program would change their practice. Of 815 older adults surveyed from 36 discrete teaching sessions, 461 (56%) thought that the medical residents delivered health information clearly (4.55 ± 0.88) and that the health topics were relevant (4.26 ± 0.92). Free-text responses showed that the program helped them understand their health concerns. This CBSL program is a feasible and effective tool for teaching internal medicine residents and older adults. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

Emerging Culture of English-Medium Instruction in Korea: Experiences of Korean and International Students

Science.gov (United States)

Kim, Jeongyeon; Tatar, Bradley; Choi, Jinsook

2014-01-01

This study aims to contrastively examine Korean and international students' experiences of taking subject courses at a Korean university. Focusing on the viewpoints of the students, rather than central authorities, we attempt to reveal how language use and cultural factors are interpenetrated in the praxis of English-medium instruction (EMI). The…

Romance of Experience, Satisfaction and Behavioral Intentions: An Empirical Examination of International Delegates in Academic Conferences

Directory of Open Access Journals (Sweden)

Ali Faizan

2014-01-01

Full Text Available The growing attention placed on experiences can be regarded as a mega-trend, and has given currency to the proposition that experiences are important for consumer’s self-perception and satisfaction with a specific visit. In order to assess this assumption, this study empirically examines the applicability of Pine and Gilmore’s ‘experience economy’ concept and examines the impact of its four dimensions i.e., education, escapism, esthetics, and entertainment on delegates’ satisfaction and behavioural intentions. Based on convenience sampling, 210 questionnaires are distributed to the delegates of 2 international academic conferences out of which 188 were deemed fit for further analysis 89% response rate. The results indicate that Pine and Gilmore’s model can further our understanding of the experience market. However, the findings in contrast with previous studies show that different experiential dimensions influence the delegates’ overall satisfaction in different contexts. For instance, the dimension of education has a relatively higher significant effect on the delegates’ overall satisfaction and behavioural intentions in the context of international academic conferences. The theoretical and practical implications of this study are also discussed.

Enhancement of international cooperation and experience exchange: international and regional cooperation in nuclear technology

International Nuclear Information System (INIS)

Henderson, R.R.

1987-01-01

This paper will explore methods that have been effective in accomplishing broad-based technology transfer relationships between international commercial nuclear organizations, and have enhanced the benefits from such relationships through mutual participation in the development of new technology. The factors involved in accomplishing technology transfer will be examined based on the 25 years of Westinghouse experience in establishing successful nuclear technology relationships with over 20 different associates world-wide. This will include information pertaining to organization, training, consultation, technical information transmission, and other important aspects of technology transfer. Additionally, the methodology of enhancing and increasing the benefits of technology transfer through cooperative development programs as produced and promoted by Weatinghouse with its associates will be examined. This will include reviews of several significant copperative programs, such as the programs for the Advanced Pressurized Water Reactor and the Integrated Protection and Control Systems for future plants. (author)

Enhancement of international cooperation and experience exchange - international and regional cooperation in nuclear technology

International Nuclear Information System (INIS)

Henderson, R.R.

1988-01-01

This paper will explore methods that have been effective in accomplishing broad-based technology transfer relationships between international commercial nuclear organizations, and have enhanced the benefits from such relationships through mutual participation in the development of new technology. The factors involved in accomplishing technology transfer will be examined based on the 25 years of Westinghouse experience in establishing successful nuclear technology relationships with over 20 different associates world-wide. This will include information pertaining to organization, training, consultation, technical information transmission, and other important aspects of technology transfer. Additionally, the methodology of enhancing and increasing the benefits of technology transfer through cooperative development programs as produced and promoted by Westinghouse with its associates will be examined. This will include reviews of several significant cooperative programs, such as the programs for the Advanced Pressurized Water Reactor and the Integrated Protection and Control Systems for future plants

Building international experiences into an engineering curriculum - a design project-based approach

Science.gov (United States)

Maldonado, Victor; Castillo, Luciano; Carbajal, Gerardo; Hajela, Prabhat

2014-07-01

This paper is a descriptive account of how short-term international and multicultural experiences can be integrated into early design experiences in an aerospace engineering curriculum. Such approaches are considered as important not only in fostering a student's interest in the engineering curriculum, but also exposing them to a multicultural setting that they are likely to encounter in their professional careers. In the broader sense, this programme is described as a model that can be duplicated in other engineering disciplines as a first-year experience. In this study, undergraduate students from Rensselaer Polytechnic Institute (RPI) and Universidad del Turabo (UT) in Puerto Rico collaborated on a substantial design project consisting of designing, fabricating, and flight-testing radio-controlled model aircraft as a capstone experience in a semester-long course on Fundamentals of Flight. The two-week long experience in Puerto Rico was organised into academic and cultural components designed with the following objectives: (i) to integrate students in a multicultural team-based academic and social environment, (ii) to practise team-building skills and develop students' critical thinking and analytical skills, and finally (iii) to excite students about their engineering major through practical applications of aeronautics and help them decide if it is a right fit for them.

Scrutinized with inadequate control and support: Interns' experiences communicating with and writing referrals to hospital radiology departments – A qualitative study

International Nuclear Information System (INIS)

Kruse, J.; Lehto, N.; Riklund, K.; Tegner, Y.; Engström, Å.

2016-01-01

Introduction: Interns' experiences communicating with and writing referrals to hospital radiology departments are important for patient safety, image quality, and decision-making in the diagnostic process. Understanding roles within the department and in the diagnostic process is important for communication. This study aimed to describe interns' experiences communicating with and writing referrals to their hospital's radiology department. Method: A qualitative study design was used. Data was collected from focus discussions with ten interns in three focus groups in Northern Sweden during 2012. The data were subjected to qualitative content analysis. Results: One theme, “a feeling of being scrutinized and lacking control”, was identified in the final categories. The interns experienced that the radiology department placed high demands on them and desired more diagnostic skills training, resources and feedback. The interns suggested the following improvements: enhanced dialogue and feedback, improved education, handy guidelines, and practice writing referrals. Conclusion: Interns need more feedback from, and dialogue with, members of the Department of Radiology. They also need more knowledge of referral guidelines, appropriateness criteria and more practice to develop their knowledge and skill for writing referrals. They describe feelings of inadequate support and feel scrutinized in demanding work conditions and need more collaboration. They also need more time and more control of radiology outcomes, and they are eager to learn. - Highlights: • Interns' experiences of writing referrals are important in the diagnostic process. • Communication between referents and radiology staff influences patient safety. • Medical interns experience insufficient diagnostic skills. • Interns need more feedback from, and dialogue with radiology staff. • The learning process could benefit from knowledge of the referrers perspective.

Lxcloud: a prototype for an internal cloud in HEP. Experiences and lessons learned

International Nuclear Information System (INIS)

Goasguen, Sebastien; Moreira, Belmiro; Roche, Ewan; Schwickerath, Ulrich

2012-01-01

Born out of the desire to virtualize our batch compute farm CERN has developed an internal cloud known as lxcloud. Since December 2010 it has been used to run a small but sufficient part of our batch workload thus allowing operational and development experience to be gained. Recently, this service has evolved to a public cloud allowing selected physics users an alternate way of accessing resources.

Proceedings of the International Workshop on Occupational Radiation Protection in Severe Accident Management 'sharing practices and experiences'

International Nuclear Information System (INIS)

2014-06-01

The objective of the Workshop on Occupational Radiation Protection in Severe Accident Management was to share practices and experiences in approaches to severe accident management. The workshop: provided an international forum for information and experience exchange amongst nuclear electricity utilities and national regulatory authorities on approaches to, and issues in severe accident management, including national and international implications. Focus was placed on sharing practices and experiences in many countries on approaches to severe accident management; identified best occupational radiation protection approaches in strategies, practices, as well as limitations for developing effective management. This included experiences in various countries; identified national experiences to be incorporated into the final version of ISOE EG-SAM report. The workshop included a series of plenary presentations that provided participants with an overview of practices and experiences in severe accident management from various countries. Furthermore, by taking into account the structure of the interim report, common themes and issues were discussed in follow-up breakout sessions. Sessions included invited speakers, moderated by designated experts, allowing participants to discuss their national experiences and possible inputs into the report. The outcomes of the breakout sessions were presented in plenary by the respective moderators followed by an open discussion, with a view towards elaborating ways forward to achieve more effective severe accident management. This document brings together the abstracts and the slides of the available presentations

Materials International Space Station Experiment (MISSE) 5 Developed to Test Advanced Solar Cell Technology Aboard the ISS

Science.gov (United States)

Wilt, David M.

2004-01-01

The testing of new technologies aboard the International Space Station (ISS) is facilitated through the use of a passive experiment container, or PEC, developed at the NASA Langley Research Center. The PEC is an aluminum suitcase approximately 2 ft square and 5 in. thick. Inside the PEC are mounted Materials International Space Station Experiment (MISSE) plates that contain the test articles. The PEC is carried to the ISS aboard the space shuttle or a Russian resupply vehicle, where astronauts attach it to a handrail on the outer surface of the ISS and deploy the PEC, which is to say the suitcase is opened 180 deg. Typically, the PEC is left in this position for approximately 1 year, at which point astronauts close the PEC and it is returned to Earth. In the past, the PECs have contained passive experiments, principally designed to characterize the durability of materials subjected to the ultraviolet radiation and atomic oxygen present at the ISS orbit. The MISSE5 experiment is intended to characterize state-of-art (SOA) and beyond photovoltaic technologies.

International boundary experiences by the United Nations

Science.gov (United States)

Kagawa, A.

2013-12-01

Over the last few decades, the United Nations (UN) has been approached by Security Council and Member States on international boundary issues. The United Nations regards the adequate delimitation and demarcation of international boundaries as a very important element for the maintenance of peace and security in fragile post-conflict situations, establishment of friendly relationships and cross-border cooperation between States. This paper will present the main principles and framework the United Nations applies to support the process of international boundary delimitation and demarcation activities. The United Nations is involved in international boundary issues following the principle of impartiality and neutrality and its role as mediator. Since international boundary issues are multi-faceted, a range of expertise is required and the United Nations Secretariat is in a good position to provide diverse expertise within the multiple departments. Expertise in different departments ranging from legal, political, technical, administrative and logistical are mobilised in different ways to provide support to Member States depending on their specific needs. This presentation aims to highlight some of the international boundary projects that the United Nations Cartographic Section has been involved in order to provide the technical support to different boundary requirements as each international boundary issue requires specific focus and attention whether it be in preparation, delimitation, demarcation or management. Increasingly, the United Nations is leveraging geospatial technology to facilitate boundary delimitation and demarcation process between Member States. Through the presentation of the various case studies ranging from Iraq - Kuwait, Israel - Lebanon (Blue Line), Eritrea - Ethiopia, Cyprus (Green Line), Cameroon - Nigeria, Sudan - South Sudan, it will illustrate how geospatial technology is increasingly used to carry out the support. In having applied a range

Effect of Experience of Internal Medicine Residents during Infectious Disease Elective on Future Infectious Disease Fellowship Application

Science.gov (United States)

2017-10-04

Experience of !ntcrnal Medicine Residents during Infectious Disease Elective on Future lntCctious Di~casc Fcllo\\vship Application Sb. GRANT N_UMBER...undefined. Since 2008 at our institution. internal medicine (!!vi) residents have been required to do a four-\\\\’eek inpatient !D rotation as an intern... Medicine Residents during Infectious Disease Elective on Fut ure Infectious Disease Fellowship Application ~ Poeter# 1440 .,...._,: OVfil"S~ ti

Fluid Physical and Transport Phenomena Studies aboard the International Space Station: Planned Experiments

Science.gov (United States)

Singh, Bhim S.

1999-01-01

This paper provides an overview of the microgravity fluid physics and transport phenomena experiments planned for the International Spare Station. NASA's Office of Life and Microgravity Science and Applications has established a world-class research program in fluid physics and transport phenomena. This program combines the vast expertise of the world research community with NASA's unique microgravity facilities with the objectives of gaining new insight into fluid phenomena by removing the confounding effect of gravity. Due to its criticality to many terrestrial and space-based processes and phenomena, fluid physics and transport phenomena play a central role in the NASA's Microgravity Program. Through widely publicized research announcement and well established peer-reviews, the program has been able to attract a number of world-class researchers and acquired a critical mass of investigations that is now adding rapidly to this field. Currently there arc a total of 106 ground-based and 20 candidate flight principal investigators conducting research in four major thrust areas in the program: complex flows, multiphase flow and phase change, interfacial phenomena, and dynamics and instabilities. The International Space Station (ISS) to be launched in 1998, provides the microgravity research community with a unprecedented opportunity to conduct long-duration microgravity experiments which can be controlled and operated from the Principal Investigators' own laboratory. Frequent planned shuttle flights to the Station will provide opportunities to conduct many more experiments than were previously possible. NASA Lewis Research Center is in the process of designing a Fluids and Combustion Facility (FCF) to be located in the Laboratory Module of the ISS that will not only accommodate multiple users but, allow a broad range of fluid physics and transport phenomena experiments to be conducted in a cost effective manner.

The International Research Experience: Executive MBA Distinctiveness.

Science.gov (United States)

Ambrose, David M.; Pol, Louis G.

1995-01-01

The University of Nebraska's Executive Master's in Business Administration (MBA) program has integrated international research activities into the curriculum. The university contracted with domestic corporations to conduct studies on prospects for international business. Research assignments include assessment of competitors, economic evaluations,…

The Emerging Workforce of International University Student Workers: Injury Experience in an Australian University

Directory of Open Access Journals (Sweden)

Yahya Thamrin

2018-03-01

Full Text Available International university students are a growing section of the workforce and are thought to be at greater risk of injury. Qualitative studies have highlighted vulnerabilities, but there is a shortage of quantitative research exploring the injury experience and associated risk factors of this emerging issue. In this study, a total of 466 university student workers across a range of study programs in a single Australian university completed an online survey, with questions relating to their background, working experience, training and injury experience. Risk factors for injury were explored in a multivariate statistical model. More than half had not received any safety training before they started work, and 10% reported having had a work injury. About half of these injuries occurred after training. Statistically significant risk factors for injury included working more than 20 h per week (adjusted odds ratio 2.20 (95% CI 1.03–4.71 and lack of confidence in discussing safety issues (AOR 2.17; 95% CI 1.13–4.16. The findings suggest the need for a more engaging and effective approach to safety education and a limit on working hours. This situation is a moral challenge for universities, in that they are effectively sponsoring young workers in the community. It is recommended that longitudinal studies of international student workers be conducted.

International radiation protection recommendations. Five years experience of ICRP Publication 26

International Nuclear Information System (INIS)

Lindell, B.; Beninson, D.; Sowby, F.D.

1983-01-01

The International Commission on Radiological Protection has issued radiation protection recommendations since 1928. The latest set of basic recommendations was adopted by the Commission on 17 January 1977, and subsequently published as ICRP Publication 26. This document has met with a wider interest than any of the previous ICRP recommendations. It has been considered to mark a radical change in the protection policy advocated by ICRP. It is not often appreciated that recommendations which are believed to be 'new' in ICRP Publication 26 had already been made in ICRP Publication 9 more than ten years earlier. In any event, ICRP Publication 26 has had a substantial impact on regulatory work in countries all over the world. It forms the basis for the Basic Safety Standards of the international organizations IAEA, ILO, OECD/NEA and WHO. The paper refers to the experience gained in using the new ICRP recommendations over the five years that have passed since ICRP Publication 26 was adopted and discusses some of the problems that have arisen in the practical application of the new recommendations in various countries. (author)

Windows® Internals

CERN Document Server

Russinovich, Mark E; Ionescu, Alex

2009-01-01

See how the core components of the Windows operating system work behind the scenes-guided by a team of internationally renowned internals experts. Fully updated for Windows Server 2008 and Windows Vista, this classic guide delivers key architectural insights on system design, debugging, performance, and support-along with hands-on experiments to experience Windows internal behavior firsthand.Delve inside Windows architecture and internals:Understand how the core system and management mechanisms work-from the object manager to services to the registryExplore internal system data structures usin

CRYSTAL-FACE Analysis and Simulations of the July 23rd Extended Anvil Case

Science.gov (United States)

Starr, David

2003-01-01

A key focus of CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and cirrus Layers - Florida Area Cirrus Experiment) was the generation and subsequent evolution of cirrus outflow from deep convective cloud systems. Present theoretical background and motivations will be discussed. An integrated look at the observations of an extended cirrus anvil cloud system observed on 23 July 2002 will be presented, including lidar and millimeter radar observation; from NASA s ER-2 and in-situ observations from NASA s WB-57 and University of North Dakota Citation. The observations will be compared to results of simulations using 1-D and 2-D high-resolution (100 meter) cloud resolving models. The CRMs explicitly account for cirrus microphysical development by resolving the evolving ice crystal size distribution (bin model) in time and space. Both homogeneous and heterogeneous nucleation are allowed in the model. The CRM simulations are driven using the output of regional simulations using MM5 that produces deep convection similar to what was observed. The MM5 model employs a 2 km inner grid (32 layers) over a 360 km domain, nested within a 6-km grid over a 600-km domain. Initial and boundary conditions for the 36-hour MM5 simulation are taken from NCEP Eta model analysis at 32 km resolution. Key issues to be explored are the settling of the observed anvil versus the model simulations, and comparisons of dynamical properties, such as vertical motions, occurring in the observations and models. The former provides an integrated measure of the validity of the model microphysics (fallspeed) while the latter is the key factor in forcing continued ice generation.

Echoes on the motor network: how internal motor control structures afford sensory experience.

Science.gov (United States)

Burgess, Jed D; Lum, Jarrad A G; Hohwy, Jakob; Enticott, Peter G

2017-12-01

Often, during daily experiences, hearing peers' actions can activate motor regions of the CNS. This activation is termed auditory-motor resonance (AMR) and is thought to represent an internal simulation of one's motor memories. Currently, AMR is demonstrated at the neuronal level in the Macaque and songbird, in conjunction with evidence on a systems level in humans. Here, we review evidence of AMR development from a motor control perspective. In the context of internal modelling, we consider data that demonstrates sensory-guided motor learning and action maintenance, particularly the notion of sensory comparison seen during songbird vocalisation. We suggest that these comparisons generate accurate sensory-to-motor inverse mappings. Furthermore, given reports of mapping decay after songbird learning, we highlight the proposal that the maintenance of these sensorimotor maps potentially explains why frontoparietal regions are activated upon hearing known sounds (i.e., AMR). In addition, we also recommend that activation of these types of internal models outside of action execution may provide an ecological advantage when encountering known stimuli in ambiguous conditions.

Cirrus clouds properties derived from polarized micro pulse lidar (p-mpl observations at the atmospheric observatory ‘el arenosillo’ (sw iberian peninsula: a case study for radiative implications

Directory of Open Access Journals (Sweden)

Águila Ana del

2018-01-01

Full Text Available Cirrus (Ci clouds are involved in Climate Change concerns since they affect the radiative balance of the atmosphere. Recently, a polarized Micro Pulse Lidar (P-MPL, standard system within NASA/MPLNET has been deployed at the INTA/Atmospheric Observatory ‘El Arenosillo’ (ARN, located in the SW Iberian Peninsula. Hence, the INTA/P-MPL system is used for Ci detection over that station for the first time. Radiative effects of a Ci case observed over ARN are examined, as reference for future long-term Ci observations. Optical and macrophysical properties are retrieved, and used for radiative transfer simulations. Data are compared to the measured surface radiation levels and all-sky images simultaneously performed at the ARN station.

Benefits of International Collaboration on the International Space Station

Science.gov (United States)

Hasbrook, Pete; Robinson, Julie A.; Brown Tate, Judy; Thumm, Tracy; Cohen, Luchino; Marcil, Isabelle; De Parolis, Lina; Hatton, Jason; Umezawa, Kazuo; Shirakawa, Masaki;

Exploring the Experiences of International Students in UK Higher Education: Possibilities and Limits of Interculturality in University Life

Science.gov (United States)

Schweisfurth, Michele; Gu, Qing

2009-01-01

This article is based on a two-year multi-method research project, funded by the UK Economic and Social Research Council, investigating the experiences of international undergraduate students in UK higher education. In investigating the influences on their experiences and the strategies that students employ, the study has also revealed something…

The Value of International Experiences for Business Students: Measuring Business Student Attitudes toward Study Abroad

Science.gov (United States)

Heffron, Sean; Maresco, Peter A.

2014-01-01

The value of an international experience--especially for students of business--continues to be an area of focus at colleges and universities. Students across all disciplines within the business curriculum: accounting, economics, finance, management, marketing, or sport management are expected by employers to possess knowledge of, and appreciation…

Supracondylar corrective osteotomy for cubitus varus--the internal rotation component and its importance. An unique bone experiment.

Directory of Open Access Journals (Sweden)

Jimulia T

1994-10-01

Full Text Available In 20 patients with cubitus varus, a clinical test suggested by Yamamoto et al (1985 was carried out to measure the internal rotation. Average internal rotation was found to be 37.5 +/- 9.390. A correction for internal rotation was carried out for all the patients having angle more than 20 degrees. Following osteotomy, post-operative Yamamoto′s angle was measured and was found to be 8.85 +/- 6.5. An experiment was carried out on postmortem human humerus with cubitus varus. The internal rotation was measured with Kirschner wires and was found to be 30 degrees. Osteotomy was carried out to eliminate varus and correct internal rotation. Radiographs taken before and after the osteotomy confirmed the correction. We conclude that this derotation has to be corrected and Yamamoto′s test should be used to assess the correction.

Level of training and experience in physicians performing interhospital transfers of adult patients in the internal medicine department

DEFF Research Database (Denmark)

Hallas, P; Folkestad, L; Brabrand, M

2009-01-01

AIM: To establish the level of training doctors who participate in interhospital transfers in Denmark. METHODS: A questionnaire was sent to every hospital department in Denmark with acute internal medicine admissions. RESULTS: Eighty-nine internal medicine departments were contacted and 84...... responded (response rate 94.4%). Of the 84 hospitals, 75 (89.3%) indicated that they perform interhospital transfers. Most transfers were performed by interns (61.3%) or senior house officers (10.7%) with only a few months' experience in their current speciality. Training in interhospital transfer...

Promoting University and Industry Links at the Regional Level: Comparing China's Reform and International Experience

Science.gov (United States)

Po, Yang; Cai, Yuzhuo; Lyytinen, Anu; Hölttä, Seppo

2016-01-01

This paper intends to learn from international experiences in order to facilitating China's ongoing regional university transformation with an ultimate goal to enhance the role of university in regional economic development and innovation. In so doing, this paper compares major models of universities of applied sciences (UAS) around the world from…

Dreams collide with reality for international experiment

CERN Document Server

Cho, Adrian

2007-01-01

"Three weeks ago, an international team released a design and cost estimate for the International Linear Collider (ILC). American physicists want to build the ILC at Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois, and researchers had hoped to break ground in 2012 and fire up the ILC's beams of electrons and positrons in 2019." (1 page)

Identity physics experiment on internal transport barriers in JT-60U and JET

Energy Technology Data Exchange (ETDEWEB)

De Vries, P C; Beurskens, M N A; Brix, M; Giroud, C; Hawkes, N C; Parail, V [EURATOM/UKAEA Association, Culham Science Centre, OX14 3DB, Abingdon (United Kingdom); Sakamoto, Y; Fujita, T; Hayashi, N; Matsunaga, G; Oyama, N; Shinohara, K; Suzuki, T; Takechi, M [Japan Atomic Energy Agency, Naka, Ibaraki-ken 311-0193 (Japan); Litaudon, X; Joffrin, E [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Crombe, K [Department of Applied Physics, Ghent University, Rozier 44, 9000 Gent (Belgium); Mantica, P [Istituto di Fisica del Plasma, EURATOM/ENEA-CNR Association, Milano (Italy); Salmi, A [Association Euratom-Tekes, Helsinki University of Technology, PO Box 4100 (Finland); Strintzi, D, E-mail: Peter.de.Vries@jet.u [National Technical University of Athens, EURATOM Association, GR-15773, Athens (Greece)

2009-12-15

A series of experiments have been carried out in 2008 at JT-60U and JET to find common characteristics and explain differences between internal transport barriers (ITBs). The identity experiments succeeded in matching the profiles of most dimensionless parameters at the time ITBs were triggered. Thereafter the q-profile development deviated due to differences in non-inductive current density profile, affecting the ITB. Furthermore, the ITBs in JET were more strongly influenced by the H-mode pedestal or edge localized modes. It was found to be difficult to match the plasma rotation characteristics in both devices. However, the wide range of Mach numbers obtained in these experiments shows that the rotation has little effect on the triggering of ITBs in plasmas with reversed magnetic shear. On the other hand the toroidal rotation and more specifically the rotational shear had an impact on the subsequent growth and allowed the formation of strong ITBs.

The Capillary Flow Experiments Aboard the International Space Station: Increments 9-15

Science.gov (United States)

Jenson, Ryan M.; Weislogel, Mark M.; Tavan, Noel T.; Chen, Yongkang; Semerjian, Ben; Bunnell, Charles T.; Collicott, Steven H.; Klatte, Jorg; dreyer, Michael E.

2009-01-01

This report provides a summary of the experimental, analytical, and numerical results of the Capillary Flow Experiment (CFE) performed aboard the International Space Station (ISS). The experiments were conducted in space beginning with Increment 9 through Increment 16, beginning August 2004 and ending December 2007. Both primary and extra science experiments were conducted during 19 operations performed by 7 astronauts including: M. Fincke, W. McArthur, J. Williams, S. Williams, M. Lopez-Alegria, C. Anderson, and P. Whitson. CFE consists of 6 approximately 1 to 2 kg handheld experiment units designed to investigate a selection of capillary phenomena of fundamental and applied importance, such as large length scale contact line dynamics (CFE-Contact Line), critical wetting in discontinuous structures (CFE-Vane Gap), and capillary flows and passive phase separations in complex containers (CFE-Interior Corner Flow). Highly quantitative video from the simply performed flight experiments provide data helpful in benchmarking numerical methods, confirming theoretical models, and guiding new model development. In an extensive executive summary, a brief history of the experiment is reviewed before introducing the science investigated. A selection of experimental results and comparisons with both analytic and numerical predictions is given. The subsequent chapters provide additional details of the experimental and analytical methods developed and employed. These include current presentations of the state of the data reduction which we anticipate will continue throughout the year and culminate in several more publications. An extensive appendix is used to provide support material such as an experiment history, dissemination items to date (CFE publication, etc.), detailed design drawings, and crew procedures. Despite the simple nature of the experiments and procedures, many of the experimental results may be practically employed to enhance the design of spacecraft engineering

Virtual Reality Simulation of the International Space Welding Experiment

Science.gov (United States)

Phillips, James A.

1996-01-01

Virtual Reality (VR) is a set of breakthrough technologies that allow a human being to enter and fully experience a 3-dimensional, computer simulated environment. A true virtual reality experience meets three criteria: (1) It involves 3-dimensional computer graphics; (2) It includes real-time feedback and response to user actions; and (3) It must provide a sense of immersion. Good examples of a virtual reality simulator are the flight simulators used by all branches of the military to train pilots for combat in high performance jet fighters. The fidelity of such simulators is extremely high -- but so is the price tag, typically millions of dollars. Virtual reality teaching and training methods are manifestly effective, and we have therefore implemented a VR trainer for the International Space Welding Experiment. My role in the development of the ISWE trainer consisted of the following: (1) created texture-mapped models of the ISWE's rotating sample drum, technology block, tool stowage assembly, sliding foot restraint, and control panel; (2) developed C code for control panel button selection and rotation of the sample drum; (3) In collaboration with Tim Clark (Antares Virtual Reality Systems), developed a serial interface box for the PC and the SGI Indigo so that external control devices, similar to ones actually used on the ISWE, could be used to control virtual objects in the ISWE simulation; (4) In collaboration with Peter Wang (SFFP) and Mark Blasingame (Boeing), established the interference characteristics of the VIM 1000 head-mounted-display and tested software filters to correct the problem; (5) In collaboration with Peter Wang and Mark Blasingame, established software and procedures for interfacing the VPL DataGlove and the Polhemus 6DOF position sensors to the SGI Indigo serial ports. The majority of the ISWE modeling effort was conducted on a PC-based VR Workstation, described below.

Conference on Atmospheric Radiation, 7th, San Francisco, CA, July 23-27, 1990, Preprints

International Nuclear Information System (INIS)

Anon.

1990-01-01

The present conference on atmospheric radiation discusses the Cirrus experiment, cloud climatologies, the earth radiation budget, the surface radiation budget, remote sensing, radiative transfer, arctic clouds and aerosols, and clouds and radiation. Attention is given to the results of the FIRE Marine Stratocumulus Observations, cirrus cloud properties derived from satellite radiances during FIRE, the dimension of a cloud's boundary, and satellite observations of cirrus clouds. Topics addressed include the seasonal variation of the diurnal cycles of the earth's radiation budget determined from ERBE, estimation of the outgoing longwave flux from NOAA AVHRR satellite observations, a comparison of observed and modeled longwave radiances, and climate monitoring using radiative entropy from ERB observations. Also discussed are approximations to the diffuse radiative properties of cloud layers, the greenhouse potential of other trace gases relative to CO2, global surface albedos estimated from ERBE data, and the energy exchange in a tropical rain forest

Experience of international projects implementation at Leningrad Nuclear Power Plant

International Nuclear Information System (INIS)

Zavialov, L.A.

2008-01-01

During the period of 1992-2007 more than 60 different projects of different specificity and budget have been successfully implemented in frames of Technical Assistance for the Commonwealth of Independent States (TACIS) Program, Project financed by European Bank for Reconstruction and Development (EBRD), as well as in frames of Agreements on Cooperation between Leningrad NPP and Radiation and Nuclear safety Authority of Finland (STUK) and Swedish Nuclear Power Inspectorate, International Co-operation Program SKI-ICP(SIP). All these projects were directed to the safety increasing of the Leningrad NPP reactor, type RBMK-1000. Implementation of the technical aid projects has been performed by different foreign companies such as Aarsleff Oy, (Finland), SGN (France), Nukem (Germany), Jergo AB (Sweden), SABAROS (Switzerland), Westinghouse (USA), Nordion (Canada), Bruel and Kjer (Denmark), Data System and Solutions (UK), SVT Braundshuz (Germany) WICOTEC (Sweden), Studsvik (Sweden) and etc. which has enough technical and organizational experience in implementation of such projects, as well as all necessary certificates and licenses for works performance. Selection of a Contractor/Supplier for a joined work performance has been carried out in accordance with the tender procedure, technical specification and a planned budget. Project financing was covered by foreign Consolidated Funds and Authorities interested in increasing of Leningrad NPP safety, which have valid intergovernmental agreements with Russian Federation on the technical assistance to be provided to the NPPs. At present time all joined international projects implemented at Leningrad NPP are financed jointly with LNPP. All projects can be divided into technical aid projects connected with development and turnkey implementation of systems and complexes and projects for supply of equipment which has no analogues in Russia but successfully used all over the world. Positive experience of the joined projects

Experience of international projects implementation at Leningrad Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Zavialov, L.A. [Leningrad Nuclear Power Plant ' Rosenergoatom' , Leningrad Region, 188540, Sosnovy Bor (Russian Federation)

2008-07-01

During the period of 1992-2007 more than 60 different projects of different specificity and budget have been successfully implemented in frames of Technical Assistance for the Commonwealth of Independent States (TACIS) Program, Project financed by European Bank for Reconstruction and Development (EBRD), as well as in frames of Agreements on Cooperation between Leningrad NPP and Radiation and Nuclear safety Authority of Finland (STUK) and Swedish Nuclear Power Inspectorate, International Co-operation Program SKI-ICP(SIP). All these projects were directed to the safety increasing of the Leningrad NPP reactor, type RBMK-1000. Implementation of the technical aid projects has been performed by different foreign companies such as Aarsleff Oy, (Finland), SGN (France), Nukem (Germany), Jergo AB (Sweden), SABAROS (Switzerland), Westinghouse (USA), Nordion (Canada), Bruel and Kjer (Denmark), Data System and Solutions (UK), SVT Braundshuz (Germany) WICOTEC (Sweden), Studsvik (Sweden) and etc. which has enough technical and organizational experience in implementation of such projects, as well as all necessary certificates and licenses for works performance. Selection of a Contractor/Supplier for a joined work performance has been carried out in accordance with the tender procedure, technical specification and a planned budget. Project financing was covered by foreign Consolidated Funds and Authorities interested in increasing of Leningrad NPP safety, which have valid intergovernmental agreements with Russian Federation on the technical assistance to be provided to the NPPs. At present time all joined international projects implemented at Leningrad NPP are financed jointly with LNPP. All projects can be divided into technical aid projects connected with development and turnkey implementation of systems and complexes and projects for supply of equipment which has no analogues in Russia but successfully used all over the world. Positive experience of the joined projects

Nurses' Experiences in a Turkish Internal Medicine Clinic With Syrian Refugees.

Science.gov (United States)

Sevinç, Sibel

2018-05-01

The increasing flow of Syrian refugees to Turkey, coupled with their extended stay, highlights the need for culturally competent health care, which includes nursing interventions. The purpose of this study was to describe the experiences of nurses who provide care for Syrian refugees in internal medicine clinics in a hospital located in Turkey. This descriptive study was based on qualitative content analysis using an inductive approach and involved discovery and description of the data. The study sample consisted of 10 nurses who work at the internal medicine clinic of a State Hospital in Turkey. Data were collected using semistructured interviews. Three themes with related subthemes were derived from the data. Nurses who participated in the study experienced: (a) Nurses found communicating with Syrian refugees and their families difficult in the clinic. (b) Nurses observed and experienced differences and similarities in caring for Turkish and Syrian patients. (c) Nurses expressed and displayed compassion toward Syrian refugees during the caring process. In order for nurses to provide the best care for Syrian refugee patients, it is important to identify cultural caring behaviors observed by nurses in the promotion of culturally congruent nursing and health care.

Growth and Expansion of the International Criticality Safety Benchmark Evaluation Project and the Newly Organized International Reactor Physics Experiment Evaluation Project

International Nuclear Information System (INIS)

J. Blair Briggs; Lori Scott; Yolanda Rugama; Enrico Satori

2007-01-01

Since ICNC 2003, the International Criticality Safety Benchmark Evaluation Project (ICSBEP) has continued to expand its efforts and broaden its scope. Criticality-alarm/shielding type benchmarks and fundamental physics measurements that are relevant to criticality safety applications are not only included in the scope of the project, but benchmark data are also included in the latest version of the handbook. A considerable number of improvements have been made to the searchable database, DICE and the criticality-alarm/shielding benchmarks and fundamental physics measurements have been included in the database. There were 12 countries participating on the ICSBEP in 2003. That number has increased to 18 with recent contributions of data and/or resources from Brazil, Czech Republic, Poland, India, Canada, and China. South Africa, Germany, Argentina, and Australia have been invited to participate. Since ICNC 2003, the contents of the ''International Handbook of Evaluated Criticality Safety Benchmark Experiments'' have increased from 350 evaluations (28,000 pages) containing benchmark specifications for 3070 critical or subcritical configurations to 442 evaluations (over 38,000 pages) containing benchmark specifications for 3957 critical or subcritical configurations, 23 criticality-alarm-placement/shielding configurations with multiple dose points for each, and 20 configurations that have been categorized as fundamental physics measurements that are relevant to criticality safety applications in the 2006 Edition of the ICSBEP Handbook. Approximately 30 new evaluations and 250 additional configurations are expected to be added to the 2007 Edition of the Handbook. Since ICNC 2003, a reactor physics counterpart to the ICSBEP, The International Reactor Physics Experiment Evaluation Project (IRPhEP) was initiated. Beginning in 1999, the IRPhEP was conducted as a pilot activity by the by the Organization of Economic Cooperation and Development (OECD) Nuclear Energy Agency

“I feel free”: Experiences of a dance intervention for adolescent girls with internalizing problems

Science.gov (United States)

Duberg, Anna; Möller, Margareta; Sunvisson, Helena

2016-01-01

Adolescent girls today suffer from internalizing problems such as somatic symptoms and mental health problems at higher rates compared to those of previous decades, and effective interventions are warranted. The aim of this study was to explore the experiences of participating in an 8-month dance intervention. This qualitative study was embedded in a randomized controlled trial of a dance intervention for adolescent girls with internalizing problems. A total of 112 girls aged 13–18 were included in the study. The dance intervention group comprised 59 girls, 24 of whom were strategically chosen to be interviewed. Data were analyzed using qualitative content analysis with an inductive approach. The experiences of the dance intervention resulted in five generic categories: (1) An Oasis from Stress, which represents the fundamental basis of the intervention; (2) Supportive Togetherness, the setting; (3) Enjoyment and Empowerment, the immediate effect; (4) Finding Acceptance and Trust in Own Ability, the outcome; and (5) Dance as Emotional Expression, the use of the intervention. One main category emerged, Finding Embodied Self-Trust That Opens New Doors, which emphasizes the increased trust in the self and the ability to approach life with a sense of freedom and openness. The central understanding of the adolescent girls’ experiences was that the dance intervention enriched and gave access to personal resources. With the non-judgmental atmosphere and supportive togetherness as a safe platform, the enjoyment and empowerment in dancing gave rise to acceptance, trust in ability, and emotional expression. Taken together, this increased self-trust and they discovered a new ability to “claim space.” Findings from this study may provide practical information on designing future interventions for adolescent girls with internalizing problems. PMID:27416014

Training School Pupils in the Scientific Method: Student Participation in an International VLF Radio Experiment

Science.gov (United States)

Denton, J. J.; Denton, M. H.; Kavanagh, A. J.; Harron, H.; Ulich, T.; Denton, J. S.

2012-01-01

We report on a school-university collaboration to involve students in the deployment, testing, and operation of a very low frequency (VLF) radio receiver as part of an international network of such experiments. A background to the collaboration is presented, along with a summary of planning and development, and the ultimate deployment of the…

Motivations, Expectations, and Experiences of Expatriate Academic Staff on an International Branch Campus in China

Science.gov (United States)

Cai, Li; Hall, Christine

2016-01-01

This article explores the experiences of non-Chinese academic staff working on an international branch campus in China. The article presents findings from an interview study that explored the expectations of expatriate staff and what motivated them to want to work abroad. The second part of the article reports on whether and how these expectations…

The experience of international nursing students studying for a PhD in the U.K: A qualitative study.

Science.gov (United States)

Evans, Catrin; Stevenson, Keith

2011-06-13

Educating nurses to doctoral level is an important means of developing nursing capacity globally. There is an international shortage of doctoral nursing programmes, hence many nurses seek their doctorates overseas. The UK is a key provider of doctoral education for international nursing students, however, very little is known about international doctoral nursing students' learning experiences during their doctoral study. This paper reports on a national study that sought to investigate the learning expectations and experiences of overseas doctoral nursing students in the UK. Semi-structured qualitative interviews were conducted in 2008/09 with 17 international doctoral nursing students representing 9 different countries from 6 different UK universities. Data were analysed thematically. All 17 interviewees were enrolled on 'traditional' 3 year PhD programmes and the majority (15/17) planned to work in higher education institutions back in their home country upon graduation. Studying for a UK PhD involved a number of significant transitions, including adjusting to a new country/culture, to new pedagogical approaches and, in some cases, to learning in a second language. Many students had expected a more structured programme of study, with a stronger emphasis on professional nursing issues as well as research - akin to the professional doctorate. Students did not always feel well integrated into their department's wider research environment, and wanted more opportunities to network with their UK peers. A good supervision relationship was perceived as the most critical element of support in a doctoral programme, but good relationships were sometimes difficult to attain due to differences in student/supervisor expectations and in approaches to supervision. The PhD was perceived as a difficult and stressful journey, but those nearing the end reflected positively on it as a life changing experience in which they had developed key professional and personal skills. Doctoral

The experience of international nursing students studying for a PhD in the U.K: A qualitative study

Directory of Open Access Journals (Sweden)

Stevenson Keith

2011-06-01

Full Text Available Abstract Background Educating nurses to doctoral level is an important means of developing nursing capacity globally. There is an international shortage of doctoral nursing programmes, hence many nurses seek their doctorates overseas. The UK is a key provider of doctoral education for international nursing students, however, very little is known about international doctoral nursing students' learning experiences during their doctoral study. This paper reports on a national study that sought to investigate the learning expectations and experiences of overseas doctoral nursing students in the UK. Methods Semi-structured qualitative interviews were conducted in 2008/09 with 17 international doctoral nursing students representing 9 different countries from 6 different UK universities. Data were analysed thematically. All 17 interviewees were enrolled on 'traditional' 3 year PhD programmes and the majority (15/17 planned to work in higher education institutions back in their home country upon graduation. Results Studying for a UK PhD involved a number of significant transitions, including adjusting to a new country/culture, to new pedagogical approaches and, in some cases, to learning in a second language. Many students had expected a more structured programme of study, with a stronger emphasis on professional nursing issues as well as research - akin to the professional doctorate. Students did not always feel well integrated into their department's wider research environment, and wanted more opportunities to network with their UK peers. A good supervision relationship was perceived as the most critical element of support in a doctoral programme, but good relationships were sometimes difficult to attain due to differences in student/supervisor expectations and in approaches to supervision. The PhD was perceived as a difficult and stressful journey, but those nearing the end reflected positively on it as a life changing experience in which they had

Perspectives on global nursing leadership: international experiences from the field.

Science.gov (United States)

Buckner, E B; Anderson, D J; Garzon, N; Hafsteinsdóttir, T B; Lai, C K Y; Roshan, R

2014-12-01

Nursing leaders from six countries engaged in a year-long discussion on global leadership development. The purpose of these dialogues was to strengthen individual and collective capacity as nursing leaders in a global society. Field experiences in practice and education were shared. Perspectives on global leadership can strengthen nurses' contributions to practice, workplace and policy issues worldwide. Transformational leadership empowers nurses' increasing confidence. Mentoring is needed to stimulate leadership development but this is lacking in many settings where nurses practice, teach and influence policy. Organizations with global mission provide opportunity for nurses' professional growth in leadership through international dialogues. Dialogues among participants were held monthly by conference calls or videoconferences. Example stories from each participant illustrated nursing leadership in action. From these exemplars, concepts were chosen to create a framework. Emerging perspectives and leadership themes represented all contexts of practice, education, research and policy. The cultural context of each country was reflected in the examples. Themes emerged that crossed global regions and countries. Themes were creativity, change, collaboration, community, context and courage. Relationships initially formed in professional organizations can be extended to intentionally facilitate global nursing leadership development. Exemplars from the dialogues demonstrated nursing leadership in health policy development within each cultural context. Recommendations are given for infrastructure development in organizations to enhance future collaborations. © 2014 International Council of Nurses.

Explaining the Learning Experiences of Clinical Procedures of the Internal Medicine Residents at Department of Gastroenterology

Directory of Open Access Journals (Sweden)

Mansoureh Taghavinia

2012-07-01

Full Text Available Introduction: the method and way of learning and teaching are effective in acquiring clinical skills, and identifying the shortcomings of learning and teaching will lead to better planning. The purpose of this study was to explain the experiences of the learning clinical procedures of the internal medicine residents in gastroenterology department. Methods: qualitative study using content thematic analysis was done. Six fourth-year residents were selected and interviewed considering purposive sampling. The data of the interviews were transcribed and analyzed after rereading. Results: the collected data are divided into three categories: learning and experience with the following four categories (learning time and experiencing, leaning and experiencing times, learning and experiencing opportunities, training and the lack of the training of some procedures. These categories are explained by using some quotes derived from the data. Conclusion: the results of this study suggest that the administrative management of internal residency is poor and should get seriously in implementation and application of intended instructions existing in the prepared program of Medical Education and Specialized Council of internal residency period. The attending physicians and residents must be aware of the content of education program at the beginning of the residency periods and the trainers must try to supervise the residents’ education.

Field experiments on solar geoengineering: report of a workshop exploring a representative research portfolio.

Science.gov (United States)

Keith, David W; Duren, Riley; MacMartin, Douglas G

2014-12-28

We summarize a portfolio of possible field experiments on solar radiation management (SRM) and related technologies. The portfolio is intended to support analysis of potential field research related to SRM including discussions about the overall merit and risk of such research as well as mechanisms for governing such research and assessments of observational needs. The proposals were generated with contributions from leading researchers at a workshop held in March 2014 at which the proposals were critically reviewed. The proposed research dealt with three major classes of SRM proposals: marine cloud brightening, stratospheric aerosols and cirrus cloud manipulation. The proposals are summarized here along with an analysis exploring variables such as space and time scale, risk and radiative forcing. Possible gaps, biases and cross-cutting considerations are discussed. Finally, suggestions for plausible next steps in the development of a systematic research programme are presented.

The Impact of EAP Study on the Academic Experiences of International Postgraduate Students in Australia

Science.gov (United States)

Terraschke, Agnes; Wahid, Ridwan

2011-01-01

EAP courses usually not only aim to improve students' level of English but also to convey useful academic study skills and introduce students to the common genres of their discipline. These are extra skills and information other international students do not have ready access to. Yet, few studies have focused on how the academic experiences of…

Westinghouse experience in using mechanical cutting for reactor vessel internals segmentation

International Nuclear Information System (INIS)

Boucau, Joseph; Fallstroem, Stefan; Segerud, Per; Kreitman, Paul J.

2010-01-01

plants dismantled to date in the US have repackaged the less activated waste back into the reactor vessel and shipped the entire assembly to the disposal site. Decisions like these can be driven by many factors such as disposal costs, transportation logistics, licensing fees, etc., but will have a significant impact on the segmentation and packaging plan so must be considered early in the planning phase. All segmentation tools are remotely controlled since the mechanical segmentation projects that Westinghouse has executed, so far, have been performed under water due to the high radiation levels. ALARA and personal safety is the number one priority during the site work. The complexity of the work requires well designed and reliable tools. Westinghouse has optimized the technologies from its experiences accumulated over the years. Its main focus has always been to improve tool handling and cutting speed, water cleanliness, fail-safe and safety aspects. Different band saws, disc saws, tube cutters and shearing tools have been developed to cut the reactor internals. All of those equipments are hydraulically driven which is very suitable for submerged applications. The purpose of this paper will be to provide an overview of the Westinghouse mechanical segmentation process, based on actual experience from the work that has been completed to date. (authors)

Loads Providing Ancillary Services: Review of InternationalExperience-- Technical Appendix: Market Descriptions

Energy Technology Data Exchange (ETDEWEB)

Grayson Heffner, Charles Goldman, Kintner-Meyer, M; Kirby, Brendan

2007-05-01

In this study, we examine the arrangements for andexperiences of end-use loads providing ancillary services (AS) in fiveelectricity markets: Australia, the United Kingdom (UK), the Nordicmarket, and the ERCOT and PJM markets in the United States. Our objectivein undertaking this review of international experience was to identifyspecific approaches or market designs that have enabled customer loads toeffectively deliver various ancillary services (AS) products. We hopethat this report will contribute to the ongoing discussion in the U.S.and elsewhere regarding what institutional and technical developments areneeded to ensure that customer loads can meaningfully participate in allwholesale electricity markets.

What International Aid Organizations Can Learn from International Adult Learning: Experiences from Cambodia

Science.gov (United States)

Berkvens, Jan

2012-01-01

Purpose: Many countries receive international support to strengthen professional capacity. The effect of these professional development activities (PDAs), however, is often negligible. This article provides useful insights on how international aid organizations could improve their PDAs, by describing an intervention developed and applied in…

Virtual Teams and International Business Teaching and Learning: The Case of the Global Enterprise Experience (GEE)

Science.gov (United States)

Gonzalez-Perez, Maria Alejandra; Velez-Calle, Andres; Cathro, Virginia; Caprar, Dan V.; Taras, Vasyl

2014-01-01

The increasing importance of global virtual teams in business is reflected in the classroom by the increased adoption of activities that facilitate real-time cross-cultural interaction. This article documents the experience of students from two Colombian universities who participated in a collaborative international project using virtual teams as…

Experience within international transport and direct rail services in meeting the IAEA requirement for a radiation protection programme(s)

International Nuclear Information System (INIS)

Billing, D.

2003-01-01

BNFL International Transport and Direct Rail Services have successfully developed appropriate Radiation Protection Programmes for their business. The business supports BNFL's worldwide Nuclear Fuel Services with key customer bases in Europe, Japan and the UK, utilising marine, rail and road modal transports. Experience in this business spans over 4 decades. The preparation of RPP's for each aspect of its operations has been made relatively straight forward in that the key elements within the internationally recognised model RPP (by WNTI) were already in place in BNFL's procedures to satisfy current National UK and International Regulations and supported by Management systems which comply with International Standards for Quality Assurance. (author)

Materials on the International Space Station - Forward Technology Solar Cell Experiment

Science.gov (United States)

Walters, R. J.; Garner, J. C.; Lam, S. N.; Vazquez, J. A.; Braun, W. R.; Ruth, R. E.; Lorentzen, J. R.; Bruninga, R.; Jenkins, P. P.; Flatico, J. M.

2005-01-01

This paper describes a space solar cell experiment currently being built by the Naval Research Laboratory (NRL) in collaboration with NASA Glenn Research Center (GRC), and the US Naval Academy (USNA). The experiment has been named the Forward Technology Solar Cell Experiment (FTSCE), and the purpose is to rapidly put current and future generation space solar cells on orbit and provide validation data for these technologies. The FTSCE is being fielded in response to recent on-orbit and ground test anomalies associated with space solar arrays that have raised concern over the survivability of new solar technologies in the space environment and the validity of present ground test protocols. The FTSCE is being built as part of the Fifth Materials on the International Space Station (MISSE) Experiment (MISSE-5), which is a NASA program to characterize the performance of new prospective spacecraft materials when subjected to the synergistic effects of the space environment. Telemetry, command, control, and communication (TNC) for the FTSCE will be achieved through the Amateur Satellite Service using the PCSat2 system, which is an Amateur Radio system designed and built by the USNA. In addition to providing an off-the-shelf solution for FTSCE TNC, PCSat2 will provide a communications node for the Amateur Radio satellite system. The FTSCE and PCSat2 will be housed within the passive experiment container (PEC), which is an approximately 2ft x2ft x 4in metal container built by NASA Langley Research Center (NASA LaRC) as part of the MISSE-5 program. NASA LaRC has also supplied a thin film materials experiment that will fly on the exterior of the thermal blanket covering the PCSat2. The PEC is planned to be transported to the ISS on a Shuttle flight. The PEC will be mounted on the exterior of the ISS by an astronaut during an extravehicular activity (EVA). After nominally one year, the PEC will be retrieved and returned to Earth. At the time of writing this paper, the

Modelling heterogeneous ice nucleation on mineral dust and soot with parameterizations based on laboratory experiments

Science.gov (United States)

Hoose, C.; Hande, L. B.; Mohler, O.; Niemand, M.; Paukert, M.; Reichardt, I.; Ullrich, R.

2016-12-01

Between 0 and -37°C, ice formation in clouds is triggered by aerosol particles acting as heterogeneous ice nuclei. At lower temperatures, heterogeneous ice nucleation on aerosols can occur at lower supersaturations than homogeneous freezing of solutes. In laboratory experiments, the ability of different aerosol species (e.g. desert dusts, soot, biological particles) has been studied in detail and quantified via various theoretical or empirical parameterization approaches. For experiments in the AIDA cloud chamber, we have quantified the ice nucleation efficiency via a temperature- and supersaturation dependent ice nucleation active site density. Here we present a new empirical parameterization scheme for immersion and deposition ice nucleation on desert dust and soot based on these experimental data. The application of this parameterization to the simulation of cirrus clouds, deep convective clouds and orographic clouds will be shown, including the extension of the scheme to the treatment of freezing of rain drops. The results are compared to other heterogeneous ice nucleation schemes. Furthermore, an aerosol-dependent parameterization of contact ice nucleation is presented.

International infectious diseases teaching to undergraduate medical students: A successful European collaborative experience.

Science.gov (United States)

Charlier, Caroline; Johannessen, Ingólfur; Mackintosh, Claire L; Wilks, David; Cauda, Roberto; Wolf, Federica I; Le Jeunne, Claire

2017-09-01

The emerging global-health paradigm requires medical teaching to be continuously redefined and updated; to this end, transnational approaches should be encouraged and medical training harmonized. Infectious diseases (ID) teaching in the current context of emerging infections, fast-increasing bacterial resistance and large-scale human migration, was chosen to develop a common international course. We report the successful implementation of a joint European undergraduate course aiming to (i) develop a common ID core curriculum among European medical schools; (ii) promote mobility among teachers and students (iii) promote international cooperation among European teachers. The course was built around teachers' mobility. It was delivered in English by a team of European medical educators from Paris Descartes University, Università Cattolica del Sacro Cuore in Rome and the University of Edinburgh to groups of 25-30 undergraduate medical students at each university. Partner Institutions officially recognized the course as substitutive of or additive to the regular curriculum. The course has been running for 3 years and received excellent satisfaction scores by students and staff as regards to scientific content, pedagogy and international exchanges. This cooperative approach demonstrates the feasibility of a harmonized European undergraduate medical education, having ID as a test experiment for future developments.

A polarized hydrogen/deuterium atomic beam source for internal target experiments

International Nuclear Information System (INIS)

Szczerba, D.; Buuren, L.D. van; Brand, J.F.J. van den; Bulten, H.J.; Ferro-Luzzi, M.; Klous, S.; Kolster, H.; Lang, J.; Mul, F.; Poolman, H.R.; Simani, M.C.

2000-01-01

A high-brightness hydrogen/deuterium atomic beam source is presented. The apparatus, previously used in electron scattering experiments with tensor-polarized deuterium (Ferro-Luzzi et al., Phys. Rev. Lett. 77 (1996) 2630; van den Brand et al., Phys. Rev. Lett. 78 (1997) 1235; Zhou et al., Phys. Rev. Lett. 82 (1998) 687; Bouwhuis et al., Phys. Rev. Lett. 82 (1999) 3755), was configured as a source for internal target experiments to measure single- and double-polarization observables, with either polarized hydrogen or vector/tensor polarized deuterium. The atomic beam intensity was enhanced by a factor of ∼2.5 by optimizing the Stern-Gerlach focusing system using high tip-field (∼1.5 T) rare-earth permanent magnets, and by increasing the pumping speed in the beam-formation chamber. Fluxes of (5.9±0.2)x10 16 1 H/s were measured in a diameter 12 mmx122 mm compression tube with its entrance at a distance of 27 cm from the last focusing element. The total output flux amounted to (7.6±0.2)x10 16 1 H/s

The International Science and Technology Center (ISTC) - Fifteen-Year Experience in Management of Innovative Nuclear and Other Programs (Information Review)

Energy Technology Data Exchange (ETDEWEB)

Gudowski, W.; Tocheny, L.V. [ISTC - International Science and Technology Center, Krasnoproletarskaya 32-34, PO Box 20, 127473 Moscow (Russian Federation)

2009-06-15

Introduction: The ISTC is a unique international organization created in Moscow in 1994 by Russia, USA, EU and Japan. Later Korea and Canada, and several CIS countries as well acceded to ISTC. The basic idea behind establishing the ISTC was to support non-proliferation of the mass destruction weapons technologies by redirecting former Soviet weapons scientists to peaceful research thus preventing the drain of dangerous knowledge and expertise from Russia and other CIS countries. Presently, the ISTC now has 40 member countries (27 from EU), representing the CIS, Europe, Asia, and North America. The Partner list includes over 200 organizations and leading industrial companies from all ISTC parties. Numerous science and technology projects were realized with the ISTC support in different areas, from bio-technologies and environmental problems to all aspects of nuclear studies, including those focused on the development of effective innovative concepts and technologies in the nuclear field, in general, and for improvement of nuclear safety, in particular. Concept: Challenge of the World Nuclear Community is to prove to Public over the World, that newly proposed nuclear concepts are safe and effective. The only acceptable method, which is trusted and accepted by Public both now and always, is basic-type and demonstration-type Experiment, in advance of computer or paper-type arguing. Important that results of these experiments are to be available for international analysis and validation. Problems are that nuclear experiments are very complex, its require special licensing, long time preparation, appealing to high-skilled personnel, purchasing by nuclear and special materials and tools, as a result - raised budgeting. In this sense the ISTC clients (first of all - nuclear and 'nuclear weapon' institutes in Russia and CIS) have all set, ready, licensed, and equipped unique nuclear installations, high-skilled personnel, good cooperation. Essential, that the ISTC

The experience of discrimination by US and Internationally educated nurses in hospital practice in the USA: a qualitative study.

Science.gov (United States)

Wheeler, Rebecca M; Foster, Jennifer W; Hepburn, Kenneth W

2014-02-01

To document experiences of nurses educated abroad and in the USA in 2 urban hospitals in the southeastern USA. Nurses are responsible for providing quality patient care. Discrimination against nurses in the workplace may create hostile environments, potentially affecting patient care and leading to higher nurse attrition rates. Structuration theory posits that agents' interactions create structures. Agents' use of resources and rules shapes interactions, potentially changing the structures. In this study, nurses described interactions with patients and their families and other healthcare personnel, their strategies for managing interactions and rationales behind their selected strategy. This study employed a qualitative, explorative approach using structuration theory. In 2011, 42 internationally educated and 40 USA-educated nurses practising in two urban hospitals in the southeastern USA were interviewed about their experiences in the workplace. Forty-one nurses were re-interviewed to explore the issues raised in the preliminary round: 21 internationally educated and 20 USA. Transcripts were analysed using the constant comparative method. Although internationally educated nurses experienced more explicit discrimination, all nurses experienced discrimination from their patients, their nurse colleagues and/or other hospital personnel. Internationally educated nurses and USA nurses shared similar coping strategies. The prevalence of nurses' experiences of discrimination suggests that healthcare institutions need to strengthen policies to effectively address this harmful practice. More research is needed about discrimination against nurses in the workplace because discrimination may have serious psychological effects that impact nurse retention and the quality of patient care. © 2013 John Wiley & Sons Ltd.

Ice nucleation by surrogates for atmospheric mineral dust and mineral dust/sulfate particles at cirrus temperatures

Directory of Open Access Journals (Sweden)

C. M. Archuleta

2005-01-01

Full Text Available This study examines the potential role of some types of mineral dust and mineral dust with sulfuric acid coatings as heterogeneous ice nuclei at cirrus temperatures. Commercially-available nanoscale powder samples of aluminum oxide, alumina-silicate and iron oxide were used as surrogates for atmospheric mineral dust particles, with and without multilayer coverage of sulfuric acid. A sample of Asian dust aerosol particles was also studied. Measurements of ice nucleation were made using a continuous-flow ice-thermal diffusion chamber (CFDC operated to expose size-selected aerosol particles to temperatures between -45 and -60°C and a range of relative humidity above ice-saturated conditions. Pure metal oxide particles supported heterogeneous ice nucleation at lower relative humidities than those required to homogeneously freeze sulfuric acid solution particles at sizes larger than about 50 nm. The ice nucleation behavior of the same metal oxides coated with sulfuric acid indicate heterogeneous freezing at lower relative humidities than those calculated for homogeneous freezing of the diluted particle coatings. The effect of soluble coatings on the ice activation relative humidity varied with the respective uncoated core particle types, but for all types the heterogeneous freezing rates increased with particle size for the same thermodynamic conditions. For a selected size of 200 nm, the natural mineral dust particles were the most effective ice nuclei tested, supporting heterogeneous ice formation at an ice relative humidity of approximately 135%, irrespective of temperature. Modified homogeneous freezing parameterizations and theoretical formulations are shown to have application to the description of heterogeneous freezing of mineral dust-like particles with soluble coatings.

Final scientific report for DOE award title: Improving the Representation of Ice Sedimentation Rates in Global Climate Models

Energy Technology Data Exchange (ETDEWEB)

Mitchell, David L. [Desert Research Institute, Reno, NV (United States)

2013-09-05

than simply using the 2D-S measurements to directly calculate V_m. By calculating V_m directly from the measured PSD, ice particle projected area and estimated mass, more accurate estimates of V_m are obtained. These V_m values were then parameterized for climate models by relating them to (1) sampling temperature and ice water content (IWC) and (2) the effective diameter (D_e) of the ice PSD. Parameterization (1) is appropriate for climate models having single-moment microphysical schemes whereas (2) is appropriate for double-moment microphysical schemes and yields more accurate V_m estimates. These parameterizations were developed for tropical cirrus clouds, Arctic cirrus, mid-latitude synoptic cirrus and mid-latitude anvil cirrus clouds based on field campaigns in these regions. An important but unexpected result of this research was the discovery of microphysical evidence indicating the mechanisms by which ice crystals are produced in cirrus clouds. This evidence, derived from PSD measurements, indicates that homogeneous freezing ice nucleation dominates in mid-latitude synoptic cirrus clouds, whereas heterogeneous ice nucleation processes dominate in mid-latitude anvil cirrus. Based on these findings, D_e was parameterized in terms of temperature (T) for conditions dominated by (1) homo- and (2) heterogeneous ice nucleation. From this, an experiment was designed for global climate models (GCMs). The net radiative forcing from cirrus clouds may be affected by the means ice is produced (homo- or heterogeneously), and this net forcing contributes to climate sensitivity (i.e. the change in mean global surface temperature resulting from a doubling of CO₂). The objective of this GCM experiment was to determine how a change in ice nucleation mode affects the predicted global radiation balance. In the first simulation (Run 1), the D_e-T relationship for homogeneous nucleation is

Experiences of Nigerian Internationally Educated Nurses Transitioning to United States Health Care Settings.

Science.gov (United States)

Iheduru-Anderson, Kechinyere C; Wahi, Monika M

2018-04-01

Successful transition to practice of internationally educated nurses (IENs) can critically affect quality of care. The aim of this study was to characterize the facilitators and barriers to transition of Nigerian IENs (NIENs) to the United States health care setting. Using a descriptive phenomenology approach, 6 NIENs were interviewed about their transitional experiences in the United States. Thematic methods were used for data analysis. The three major themes identified from the participants' stories were "fear/anger and disappointment" (FAD), "road/journey to success/overcoming challenges" (RJO), and "moving forward" (MF). The FAD theme predominated, including experiences of racism, bullying, and inequality. The RJO theme included resilience, and the MF theme encompassed personal growth. NIENs face personal and organizational barriers to adaptation, especially fear, anger and disappointment. Future research should seek to develop a model for optimal adaptation that focuses on improving both personal and organizational facilitators and decreasing barriers.

International Experience of the Development of Corporate Social Responsibility: Comparative Analysis of the Influence of the State

Directory of Open Access Journals (Sweden)

Maria Rybalko

2016-09-01

Full Text Available The paper aims to provide analysis of the international experience of the development of corporate social responsibility (CSR and to provide stimulation methods used by the state to develop CSR in Russia. The study is based on the identification of characteristics of CSR development in Russia; it subsequently concludes the most appropriate methods for the Russian state and business interaction in this sphere. Determination of the level and stage of the development of CSR in Russia is carried out by multivariate statistical (cluster analysis. The results of the study of international experience in the development of corporate responsibility and the results of the cluster analysis were used for the further improvement of the state policy in this field in Russia. This paper proposes a number of measures aimed both at improving conditions for socially responsible companies and at increasing the disclosure of information in the field of CSR and improvement of its quality.

Power transmission pricing: issues and international experience

International Nuclear Information System (INIS)

Bodenhoefer, H.J.; Wohlgemuth, N.

2001-01-01

A key aspect of electricity industry reorganization is transmission pricing because it heavily influences the degree of effective competition in 'liberalized' electricity markets. this paper presents an overview transmission pricing models, of issues related to an effective design of a transmission pricing approach, and presents approaches implemented internationally. A conclusion is that, due to the great number of institutional designs of electricity market organizations, particularly in Europe, it will be difficult to design/implement a model of cross-border transmission pricing that is capable of inducing a high degree of non-discriminatory international competition in electricity markets. (author)

The role of the faculty mentor to the REU experience: insights from an international REU

Science.gov (United States)

Houser, C.; Cahill, A. T.; Lemmons, K.

2012-12-01

The Texas A&M REU in Costa Rica provides students with an opportunity to participate in research on the ecohydrology of a tropical pre-montane forest. The international and field components of this program require both that students to work in research clusters of several faculty and students, and that each of the clusters contribute to a primary research question of closing the water budget for a small watershed. Specifically, students and faculty participate in precipitation (P), evapotranspiration (E), hydrology (Q) or subsurface storage (DS) research clusters. It is argued that having the students at a central research station location and focusing their research on a common research problem is an important aspect of an international REU program to avoid a feeling of isolation and to ensure that the students remain safe in their research and during their free time. However, this shared experience and research question can highlight differences among the faculty mentors and make the students evaluate their individual experience more critically. To better understand the relationship between the REU student and their faculty mentor(s), we have been conducting pre- and post-surveys, interviews, and focus groups to understand their experience in the REU and the manner in which the faculty mentor can affect that experience and the desire to continue in research. Results of the pre-trip survey suggest that the undergraduate students are most concerned about their projects and show little no concern about the faculty mentor with whom they will be completing their research. Post-trip results from 2011 and 2012 suggest that mentors had a much greater impact on the experience than expected. Many students said that their future research/graduate school plans were significantly affected by their REU mentor relationship. One student said that by working closely with mentors, "you know that what you are doing and learning is pertinent because you are learning it from actual

Applying new science leadership theory in planning an international nursing student practice experience in Nepal.

Science.gov (United States)

Doyle, Rose Marie

2004-09-01

Planning an international practice experience for nursing students is a challenging, but rewarding, opportunity. Kwantlen University College faculty members' experience of planning for 8 Bachelor of Science in Nursing students to study abroad was no exception. Faculty members' and students' interest prompted a request for a placement in Nepal. The faculty members involved in the planning were dedicated to using a process that would enable them to remain true to the program philosophy and theoretical underpinnings throughout the entire experience, from the planning phase to the follow-up presentation. Using Wheatley's theory, the students and faculty members reexamined their personal leadership styles to ensure they remained relationship focused, rather than task focused. Wheatley maintained that because the potentiality lies in building strong relationships, it is important to support the creative power that lies in those involved in a project. This article describes new science leadership and relates it to the planning phase for the practice experience in Nepal. Then, reflections on how the philosophy of the program may have influenced the experience are shared. Finally, critical reflection on using this theory in nursing education is presented.

The International Heat Stress Genotype Experiment for Modeling Wheat Response to Heat: Field Experiments and AgMIP-Wheat Multi-Model Simulations

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Martre, Pierre; Reynolds, Matthew P.; Asseng, Senthold; Ewert, Frank; Alderman, Phillip D.; Cammarano, Davide; Maiorano, Andrea; Ruane, Alexander C.; Aggarwal, Pramod K.; Anothai, Jakarat;

Power uprates in nuclear power plants: international experiences and approaches for implementation

International Nuclear Information System (INIS)

Kang, Ki Sig

2008-01-01

The greater demand for electricity and the available capacity within safety margins in some operating NPPs are prompting nuclear utilities to request license modification to enable operation at a higher power level, beyond their original license provisions. Such plant modifications require an in-depth safety analysis to evaluate the possible safety impact. The analysis must consider the thermo hydraulic, radiological and structural aspects, and the plant behavior, while taking into account the capability of the structures, systems and components, and the reactor protection and safeguard systems set points. The purpose of this paper is to introduce international experiences and approaches for implementation of power uprates related to the reactor thermal power of nuclear power plants. The paper is intended to give the reader a general overview of the major processes, work products, issues, challenges, events, and experiences in the power uprates program. The process of increasing the licensed power level of a nuclear power plants is called a power uprate. One way of increasing the thermal output from a reactor is to increase the amount of fissile material in use. It is also possible to increase the core power by increasing the performance of the high power bundles. Safety margins can be maintained by either using fuels with a higher performance, or through the use of improved methods of analysis to demonstrate that the required margins are retained even at the higher power levels. The paper will review all types of power uprates, from small to large, and across various reactor types, including light and heavy water, pressurized, and boiling water reactors. Generally, however, the content of the report focuses on power uprates of the stretch and extended type. The International Atomic Energy Agency (IAEA) is developing a technical guideline on power uprates and side effects of power uprates in nuclear power plants

Intercomparison study and optical asphericity measurements of small ice particles in the CERN CLOUD experiment

Science.gov (United States)

Nichman, Leonid; Järvinen, Emma; Dorsey, James; Connolly, Paul; Duplissy, Jonathan; Fuchs, Claudia; Ignatius, Karoliina; Sengupta, Kamalika; Stratmann, Frank; Möhler, Ottmar; Schnaiter, Martin; Gallagher, Martin

2017-09-01

Optical probes are frequently used for the detection of microphysical cloud particle properties such as liquid and ice phase, size and morphology. These properties can eventually influence the angular light scattering properties of cirrus clouds as well as the growth and accretion mechanisms of single cloud particles. In this study we compare four commonly used optical probes to examine their response to small cloud particles of different phase and asphericity. Cloud simulation experiments were conducted at the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at European Organisation for Nuclear Research (CERN). The chamber was operated in a series of multi-step adiabatic expansions to produce growth and sublimation of ice particles at super- and subsaturated ice conditions and for initial temperatures of -30, -40 and -50 °C. The experiments were performed for ice cloud formation via homogeneous ice nucleation. We report the optical observations of small ice particles in deep convection and in situ cirrus simulations. Ice crystal asphericity deduced from measurements of spatially resolved single particle light scattering patterns by the Particle Phase Discriminator mark 2 (PPD-2K, Karlsruhe edition) were compared with Cloud and Aerosol Spectrometer with Polarisation (CASPOL) measurements and image roundness captured by the 3View Cloud Particle Imager (3V-CPI). Averaged path light scattering properties of the simulated ice clouds were measured using the Scattering Intensity Measurements for the Optical detectioN of icE (SIMONE) and single particle scattering properties were measured by the CASPOL. We show the ambiguity of several optical measurements in ice fraction determination of homogeneously frozen ice in the case where sublimating quasi-spherical ice particles are present. Moreover, most of the instruments have difficulties of producing reliable ice fraction if small aspherical ice particles are present, and all of the instruments cannot separate perfectly

NanoJapan: international research experience for undergraduates program: fostering U.S.-Japan research collaborations in terahertz science and technology of nanostructures

Science.gov (United States)

Phillips, Sarah R.; Matherly, Cheryl A.; Kono, Junichiro

2014-09-01

The international nature of science and engineering research demands that students have the skillsets necessary to collaborate internationally. However, limited options exist for science and engineering undergraduates who want to pursue research abroad. The NanoJapan International Research Experience for Undergraduates Program is an innovative response to this need. Developed to foster research and international engagement among young undergraduate students, it is funded by a National Science Foundation Partnerships for International Research and Education (PIRE) grant. Each summer, NanoJapan sends 12 U.S. students to Japan to conduct research internships with world leaders in terahertz (THz) spectroscopy, nanophotonics, and ultrafast optics. The students participate in cutting-edge research projects managed within the framework of the U.S-Japan NSF-PIRE collaboration. One of our focus topics is THz science and technology of nanosystems (or `TeraNano'), which investigates the physics and applications of THz dynamics of carriers and phonons in nanostructures and nanomaterials. In this article, we will introduce the program model, with specific emphasis on designing high-quality international student research experiences. We will specifically address the program curriculum that introduces students to THz research, Japanese language, and intercultural communications, in preparation for work in their labs. Ultimately, the program aims to increase the number of U.S. students who choose to pursue graduate study in this field, while cultivating a generation of globally aware engineers and scientists who are prepared for international research collaboration.

International Summer School on Astronomy and Space Science in Chile, first experience.

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Stepanova, M.; Arellano-Baeza, A. A.

I International Summer School on Astronomy and Space Science took place in the Elqui Valley Chile January 15-29 2005 Eighty 12-17 year old students from Chile Russia Venezuela and Bulgaria obtained a valuable experience to work together with outstanding scientists from Chile and Russia and with Russian cosmonaut Alexander Balandine They also had opportunity to visit the main astronomical observatories and to participate in workshops dedicated to the telescope and satellite design and remote sensing This activity was supported by numerous institutions in Chile including the Ministry of Education the European Southern Observatory Chilean Space Agency Chilean Air Force Latin American Association of Space Geophysics the principal Chilean universities and the First Lady Mrs Luisa Duran

Experiences of an international trade action with irradiated onions between GDR and Hungary

International Nuclear Information System (INIS)

Zachariev, G.; Kiss, I.; Luther, T.; Huebner, G.; Doellstaedt, R.

1988-01-01

Extensive work has been carried out in the field of food irradiation in the GDR and Hungary in recent years. The irradiation of onions for sprout inhibition has reached a commercial stage in the GDR of more than 5,000 tons in 1986. The export of onions is the first example of international trade in irradiated food between socialist countries. Experiences of this trade is presented in the paper. Results of quality control of the bulbs (losses in weight an quality) after an intermediate storage period are discussed. Hungarian consumer reactions to irradiated onions is also evaluated. (author)

Flow Boiling and Condensation Experiment (FBCE) for the International Space Station

Science.gov (United States)

Mudawar, Issam; O'Neill, Lucas; Hasan, Mohammad; Nahra, Henry; Hall, Nancy; Balasubramaniam, R.; Mackey, Jeffrey

2016-01-01

An effective means to reducing the size and weight of future space vehicles is to replace present mostly single-phase thermal management systems with two-phase counterparts. By capitalizing upon both latent and sensible heat of the coolant rather than sensible heat alone, two-phase thermal management systems can yield orders of magnitude enhancement in flow boiling and condensation heat transfer coefficients. Because the understanding of the influence of microgravity on two-phase flow and heat transfer is quite limited, there is an urgent need for a new experimental microgravity facility to enable investigators to perform long-duration flow boiling and condensation experiments in pursuit of reliable databases, correlations and models. This presentation will discuss recent progress in the development of the Flow Boiling and Condensation Experiment (FBCE) for the International Space Station (ISS) in collaboration between Purdue University and NASA Glenn Research Center. Emphasis will be placed on the design of the flow boiling module and on new flow boiling data that were measured in parabolic flight, along with extensive flow visualization of interfacial features at heat fluxes up to critical heat flux (CHF). Also discussed a theoretical model that will be shown to predict CHF with high accuracy.

Concordia, Antarctica, seismic experiment for the International Polar Year (CASE-IPY

Directory of Open Access Journals (Sweden)

Alessia Maggi

2014-06-01

Full Text Available The CASE-IPY project, part of the larger POLENET initiative of geophysical observations for the International Polar Year, was built on our extensive experience of running seismological stations in Antarctica, both on rock sites (Dumont d’Urville station, and directly on the ice plateau (Concordia station. For CASE-IPY, we deployed 8 temporary seismic stations on the Antarctic plateau: 3 situated near Concordia itself (starting 2008, and the other 5 regularly spaced between Concordia and Vostok (2010-2012, following the maximum in ice topography. The technical problems we have encountered in our field deployments were essentially due to a combination of extreme environmental conditions and isolation of deployment sites. The 3 stations near Concordia were used as test sites to experiment different solutions, and to converge on a design for the 5 main stations. Results from the nearest stations, which transmit data regularly to Concordia, are very promising. The data recorded by our stations will be distributed widely in the scientific community. We expect them to be exploited essentially for structural studies involving Antarctica itself (its ice-cap, crust and lithosphere via receiver functions, noise correlation, and surface-wave tomography, but also for studies of the Earth’s core.

Can an International Field Experience Assist Health and Physical Education Pre-Service Teachers to Develop Cultural Competency?

Science.gov (United States)

Winslade, Matthew

2016-01-01

An emerging focus of teacher education courses within countries such as Australia centres on the development of cultural competency. An international practicum experience or student mobility programme embedded within pre-service teacher education programmes is one way to provide such an opportunity. In subject areas such as Health and Physical…

Electron cooling application for luminosity preservation in an experiment with internal targets at COSY

CERN Document Server

Meshkov, I N; Maier, R; Prasuhn, D; Sidorin, A O; Smirnov, A V; Stein, H J; Stockhorst, H; Trubnikov, G V

2003-01-01

This report is an investigation of the beam parameter evolution in the experiments with internal target. In calculations of the proton and deuteron beams we concentrated on cluster, atomic beam, storage cell and pellet targets at ANKE experiment mainly. In these calculations electron and stochastic cooling, intrabeam scattering, scattering on the target and residual gas atoms are taken into account. Beam parameter evolution is investigated in the long-term time scale, up to one hour, at different beam energies in the range from 1.0 to 2.7 GeV for proton beam and from 1 to 2.11 GeV for deuteron beam. The results of numerical simulations of the proton and deuteron beam parameters at different energies obtained using new version of BETACOOL program (elaborated at the first stage of this work [1]) are presented. Optimum parameters of the electron cooling system are estimated. The COSY experiment requirements can be satisfied even when electron cooling time is rather long. That allows to apply an electron cooling ...

X-Culture: An International Project in the Light of Experience Gained over the Years (2010-2016

Directory of Open Access Journals (Sweden)

József Poór

2016-12-01

Full Text Available The X-Culture project is an innovative modern form of experiential learning predominantly in International Management and International Business. Although experiential learning has some advantages, namely, developing cross-cultural competencies, cultural intelligence, intercultural communication and management skills, differences in personality or conditions also arise as a downside. X-Culture has been evolving throughout the years since 2010 when the original objective was to supplement the theoretical material and in-class teaching. Nowadays more than 4000 master, bachelor and MBA students, mostly of management and economics from more than 37 countries, take part in the project every semester. X-Culture is aimed at students of International Business college courses and training programs with the task of writing a business report or consulting propositions by offering business solutions for a hypothetical client.  This paper outlines the theoretical background of the X-culture project. It describes the evolution and practical and theoretical experience of this project since 2010.

Asian International Students’ Perceptions of their University Experience

Directory of Open Access Journals (Sweden)

Cody J. Perry

2016-12-01

Full Text Available Asian students make up the largest proportion of international students who study in the United States. Seeking a degree in higher education can be challenging for any student, but Asian students often encounter more obstacles to completion than many other international and domestic students. Culture, family and health concerns, and safety are some of the largest concerns that this study found among Asian students in the US. The study found that East-Asian international students had more issues than students from other parts of Asia and difficulty with the English language was of major importance to respondents. In addition, safety is an issue that Asian students were concerned with while studying in the US. The study was exploratory in nature and informs the field on future avenues of research.

The role of religiosity, coping strategies, self-efficacy and personality dimensions in the prediction of Iranian undergraduate rehabilitation interns' satisfaction with their clinical experience.

Science.gov (United States)

Mirsaleh, Y R; Rezai, H; Kivi, S R; Ghorbani, R

2010-12-01

to investigate the relationship between religiosity, coping styles, self-efficacy and personality dimensions as predictors of satisfaction with clinical experience in rehabilitation interns during transition from academic study to clinical internship. a cross-sectional survey design. five rehabilitation faculties. three hundred and eighteen undergraduate rehabilitation interns, including physical therapy, occupational therapy and speech and language pathology students. Islamic Religiosity Scale, Ways of Coping Questionnaire, General Self-efficacy Scale, NEO Five Factor Inventory, and Satisfaction with Clinical Experiences Questionnaire. religiosity, problem-focused coping and general self-efficacy had significant positive correlation with satisfaction with clinical internship in rehabilitation students. Among personality dimensions, openness, agreement and consciousness had significant positive correlation with satisfaction with clinical experience and neuroticism had significant negative correlation with satisfaction with clinical experience. The results of regression analysis demonstrated that religiosity and self-efficacy had important roles in the prediction of satisfaction with clinical experience in all the rehabilitation intern students of three disciplines (physical therapy, occupational therapy, and speech and language pathology). religiosity, problem-focused coping and general self-efficacy seem to be good predictors of satisfaction with clinical internship in rehabilitation students.

Small-scale variability in tropical tropopause layer humidity

Science.gov (United States)

Jensen, E. J.; Ueyama, R.; Pfister, L.; Karcher, B.; Podglajen, A.; Diskin, G. S.; DiGangi, J. P.; Thornberry, T. D.; Rollins, A. W.; Bui, T. V.; Woods, S.; Lawson, P.

2016-12-01

Recent advances in statistical parameterizations of cirrus cloud processes for use in global models are highlighting the need for information about small-scale fluctuations in upper tropospheric humidity and the physical processes that control the humidity variability. To address these issues, we have analyzed high-resolution airborne water vapor measurements obtained in the Airborne Tropical TRopopause EXperiment over the tropical Pacific between 14 and 20 km. Using accurate and precise 1-Hz water vapor measurements along approximately-level aircraft flight legs, we calculate structure functions spanning horizontal scales ranging from about 0.2 to 50 km, and we compare the water vapor variability in the lower (about 14 km) and upper (16-19 km) Tropical Tropopause Layer (TTL). We also compare the magnitudes and scales of variability inside TTL cirrus versus in clear-sky regions. The measurements show that in the upper TTL, water vapor concentration variance is stronger inside cirrus than in clear-sky regions. Using simulations of TTL cirrus formation, we show that small variability in clear-sky humidity is amplified by the strong sensitivity of ice nucleation rate to supersaturation, which results in highly-structured clouds that subsequently drive variability in the water vapor field. In the lower TTL, humidity variability is correlated with recent detrainment from deep convection. The structure functions indicate approximately power-law scaling with spectral slopes ranging from about -5/3 to -2.

Previous International Experience, Cross-Cultural Training, and Expatriates' Cross-Cultural Adjustment: Effects of Cultural Intelligence and Goal Orientation

Science.gov (United States)

Koo Moon, Hyoung; Kwon Choi, Byoung; Shik Jung, Jae

2012-01-01

Although various antecedents of expatriates' cross-cultural adjustment have been addressed, previous international experience, predeparture cross-cultural training, and cultural intelligence (CQ) have been most frequently examined. However, there are few attempts that explore the effects of these antecedents simultaneously or consider the possible…

International Students: A Vulnerable Student Population

Science.gov (United States)

Sherry, Mark; Thomas, Peter; Chui, Wing Hong

2010-01-01

This study examines the experiences of international students at The University of Toledo, where international students comprise approximately 10% of the student population. It highlights problems international students experience such as adapting to a new culture, English language problems, financial problems and lack of understanding from the…

Microwave heating device for internal heating convection experiments, applied to Earth's mantle dynamics.

Science.gov (United States)

Surducan, E; Surducan, V; Limare, A; Neamtu, C; Di Giuseppe, E

2014-12-01

We report the design, construction, and performances of a microwave (MW) heating device for laboratory experiments with non-contact, homogeneous internal heating. The device generates MW radiation at 2.47 GHz from a commercial magnetron supplied by a pulsed current inverter using proprietary, feedback based command and control hardware and software. Specially designed MW launchers direct the MW radiation into the sample through a MW homogenizer, devised to even the MW power distribution into the sample's volume. An adjustable MW circuit adapts the MW generator to the load (i.e., the sample) placed in the experiment chamber. Dedicated heatsinks maintain the MW circuits at constant temperature throughout the experiment. Openings for laser scanning for image acquisition with a CCD camera and for the cooling circuits are protected by special MW filters. The performances of the device are analyzed in terms of heating uniformity, long term output power stability, and load matching. The device is used for small scale experiments simulating Earth's mantle convection. The 30 × 30 × 5 cm(3) convection tank is filled with a water‑based viscous fluid. A uniform and constant temperature is maintained at the upper boundary by an aluminum heat exchanger and adiabatic conditions apply at the tank base. We characterize the geometry of the convective regime as well as its bulk thermal evolution by measuring the velocity field by Particle Image Velocimetry and the temperature field by using Thermochromic Liquid Crystals.