bluuebunny/crossref_metadata_2025 huggingface dataset:
An Improved Snow Scheme for the ECMWF Land Surface Model: Description and Offline Validation
Authors: Dutra Emanuel , Balsamo Gianpaolo , Viterbo Pedro , Miranda Pedro M. A. , Beljaars Anton , Schär Christoph , Elder Kelly
Published: July 2010

A new snow scheme for the European Centre for Medium-Range Weather Forecasts (ECMWF) land surface model has been tested and validated. The scheme includes a new parameterization of snow density, incorporating a liquid water reservoir, and revised formulations for the subgrid snow cover fraction and snow albedo. Offline validation (covering a wide range of spatial and temporal scales) includes simulations for several observation sites from the Snow Models Intercomparison Project-2 (SnowMIP2) and global simulations driven by the meteorological forcing from the Global Soil Wetness Project-2 (GSWP2) and by ECMWF Re-Analysis ERA-Interim. The new scheme reduces the end of season ablation biases from 10 to 2 days in open areas and from 21 to 13 days in forest areas. Global GSWP2 results are compared against basin-scale runoff and terrestrial water storage. The new snow density parameterization increases the snow thermal insulation, reducing soil freezing and leading to an improved hydrological cycle. Simulated snow cover fraction is compared against NOAA/National Environmental Satellite, Data, and Information Service (NESDIS) with a reduction of the negative bias of snow-covered area of the original snow scheme. The original snow scheme had a systematic negative bias in surface albedo when compared against Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data. The new scheme reduces the albedo bias, consequently reducing the spatial- and time-averaged surface net shortwave radiation bias by 5.2 W m−2 in 14% of the Northern Hemisphere land. The new snow scheme described in this paper was introduced in the ECMWF operational forecast system in September 2009 (cycle 35R3).
Pacific Decadal Oscillation Climate Variability and Temporal Pattern of Winter Flows in Northwestern North America
Authors: Khaliq M. N. , Gachon P.
Published: July 2010

There is growing concern about the effects of large-scale oceanic atmospheric climate variability, such as the Pacific decadal oscillation (PDO), on regional hydrology and water resources. In this paper, the effects of PDO on temporal patterns of winter (January–March) flow in northwestern North America (NWNA), which is believed to be a PDO-sensitive region, is studied for the period 1943–2007 using daily streamflow data from a much larger set of 179 stations, compared to previous studies in which only smaller subsets of these stations were analyzed. Time series of winter flows were divided into two nonoverlapping blocks corresponding to change points detected in time series of December–March mean monthly PDO indices. Both parametric and nonparametric measures of correlation and average percentage differences and average standardized differences from the period-of-record mean were explored. Like some of the previous studies, it is found that, on average, winter flows tend to be higher (lower) during the warm (cold) phase of the PDO and that establishes the physical link between large-scale climate variability and basin response. It is shown that the serial structure of time series of PDO indices conforms to that of a stochastic process with long-term persistence (LTP). Based on this finding and the climate–streamflow physical link, it is plausible to investigate temporal variations in winter flows with the LTP hypothesis, in addition to assuming merely independence (IND) or short-term persistence (STP). The results of the analysis demonstrate that the LTP mechanism, in combination with the STP, is able to explain more than half of the significant trends noted, with the IND assumption suggesting that the significance of trends reported in previous studies in NWNA may have been overstated. This result has important implications for future planning of regional water resources.
Changes in the Ventilation of the Oxygen Minimum Zone of the Tropical North Atlantic
Authors: Brandt Peter , Hormann Verena , Körtzinger Arne , Visbeck Martin , Krahmann Gerd , Stramma Lothar , Lumpkin Rick , Schmid Claudia
Published: July 2010

Changes in the ventilation of the oxygen minimum zone (OMZ) of the tropical North Atlantic are studied using oceanographic data from 18 research cruises carried out between 28.5° and 23°W during 1999–2008 as well as historical data referring to the period 1972–85. In the core of the OMZ at about 400-m depth, a highly significant oxygen decrease of about 15 μmol kg−1 is found between the two periods. During the same time interval, the salinity at the oxygen minimum increased by about 0.1. Above the core of the OMZ, within the central water layer, oxygen decreased too, but salinity changed only slightly or even decreased. The scatter in the local oxygen–salinity relations decreased from the earlier to the later period suggesting a reduced filamentation due to mesoscale eddies and/or zonal jets acting on the background gradients. Here it is suggested that latitudinally alternating zonal jets with observed amplitudes of a few centimeters per second in the depth range of the OMZ contribute to the ventilation of the OMZ. A conceptual model of the ventilation of the OMZ is used to corroborate the hypothesis that changes in the strength of zonal jets affect mean oxygen levels in the OMZ. According to the model, a weakening of zonal jets, which is in general agreement with observed hydrographic evidences, is associated with a reduction of the mean oxygen levels that could significantly contribute to the observed deoxygenation of the North Atlantic OMZ.
Response of the Southern Ocean to the Southern Annular Mode: Interannual Variability and Multidecadal Trend
Authors: Treguier A. M. , Le Sommer J. , Molines J. M. , de Cuevas B.
Published: July 2010

The authors evaluate the response of the Southern Ocean to the variability and multidecadal trend of the southern annular mode (SAM) from 1972 to 2001 in a global eddy-permitting model of the DRAKKAR project. The transport of the Antarctic Circumpolar Current (ACC) is correlated with the SAM at interannual time scales but exhibits a drift because of the thermodynamic adjustment of the model (the ACC transport decreases because of a low renewal rate of dense waters around Antarctica). The interannual variability of the eddy kinetic energy (EKE) and the ACC transport are uncorrelated, but the EKE decreases like the ACC transport over the three decades, even though meridional eddy fluxes of heat and buoyancy remain stable. The contribution of oceanic eddies to meridional transports is an important issue because a growth of the poleward eddy transport could, in theory, oppose the increase of the mean overturning circulation forced by the SAM. In the authors’ model, the total meridional circulation at 50°S is well correlated with the SAM index (and the Ekman transport) at interannual time scales, and both increase over three decades between 1972 and 2001. However, given the long-term drift, no SAM-linked trend in the eddy contribution to the meridional overturning circulation is detectable. The increase of the meridional overturning is due to the time-mean component and is compensated by an increased buoyancy gain at the surface. The authors emphasize that the meridional circulation does not vary in a simple relationship with the zonal circulation. The model solution points out that the zonal circulation and the eddy kinetic energy are governed by different mechanisms according to the time scale considered (interannual or decadal).
Observations of the Florida and Yucatan Currents from a Caribbean Cruise Ship
Authors: Rousset Clément , Beal Lisa M.
Published: July 2010

The Yucatan and Florida Currents represent the majority of the warm-water return path of the global thermohaline circulation through the tropical/subtropical North Atlantic Ocean. Their transports are quantified and compared by analyzing velocity data collected aboard the cruise ship Explorer of the Seas. From 157 crossings between May 2001 and May 2006, the mean transport of the Florida Current at 26°N was estimated to be 30.8 ± 3.2 Sv (1 Sv ≡ 106 m3 s−1), with seasonal amplitude of 2.9 Sv. Upstream, the Yucatan Current was estimated from 90 crossings to be 30.3 ± 5 Sv, with seasonal amplitude of 2.7 Sv. These two currents are shown to be linked at seasonal time scales. Hence, contrary to former results, it was found that transports through the Florida Straits and the Yucatan Channel are similar, with the implication that only small inflows occur through minor channels between them.
Cloud Classification Based on Structure Features of Infrared Images
Authors: Liu Lei , Sun Xuejin , Chen Feng , Zhao Shijun , Gao Taichang
Published: July 2010

Some cloud structure features that can be extracted from infrared images of the sky are suggested for cloud classification. Both the features and the classifier are developed over zenithal images taken by the whole-sky infrared cloud-measuring system (WSIRCMS), which is placed in Nanjing, China. Before feature extraction, the original infrared image was smoothed to suppress noise. Then, the image was enhanced using top-hat transformation and a high-pass filtering. Edges are detected from the enhanced image after adaptive optimization threshold segmentation and morphological edge detection. Several structural features are extracted from the segment image and edge image, such as cloud gray mean value (ME), cloud fraction (ECF), edge sharpness (ES), and cloud mass and gap distribution parameters, including very small-sized cloud mass and gaps (SMG), middle-sized cloud gaps (MG), medium–small-sized cloud gaps (MSG), and main cloud mass (MM). It is found that these features are useful for distinguishing cirriform, cumuliform, and waveform clouds. A simple but efficient supervised classifier called the rectangle method is used to do cloud classification. The performance of the classifier is assessed with an a priori classification carried out by visual inspection of 277 images. The index of agreement is 90.97%.
Simulation and Interpretation of the Phase Data Used by the Radar Refractivity Retrieval Algorithm
Authors: Park Shinju , Fabry Frédéric
Published: July 2010

The radar refractivity retrieval algorithm applied to radar phase measurements from ground targets can provide high-resolution, near-surface moisture estimates in time and space. The reliability of the retrieval depends on the quality of the returned phase measurements, which are affected by factors such as 1) the vertical variation of the refractive index along the ray path and 2) the properties of illuminated ground targets (e.g., the height and shape of the targets intercepted by radar rays over complex terrain). These factors introduce ambiguities in the phase measurement that have not yet been considered in the refractivity algorithm and that hamper its performance.

A phase measurement simulator was designed to better understand the effect of these factors. The results from the simulation were compared with observed phase measurements for selected atmospheric propagation conditions estimated from low-level radio sounding profiles. Changes in the vertical gradient of refractivity coupled with the varying heights of targets are shown to have some influence on the variability of phase fields. However, they do not fully explain the noisiness of the real phase observations because other factors that are not included in the simulation, such as moving ground targets, affect the noisiness of phase measurements.
A Global Evaluation of Ocean Bottom Pressure from GRACE, OMCT, and Steric-Corrected Altimetry
Authors: Chambers Don P. , Willis Josh K.
Published: July 2010

Ocean bottom pressure (OBP) from the Gravity Recovery and Climate Experiment (GRACE) and the Ocean Model for Circulation and Tides (OMCT) are compared globally with OBP computed from altimetry corrected for steric variations from Argo floats from January 2005 to December 2007. Two methods of smoothing the GRACE data are examined. The first uses a standard Gaussian smoother with a radius of 300 km. The second method projects those smoothed maps onto empirical orthogonal functions derived from OMCT in a least squares estimation in order to produce maps that better agree with the physical processes embodied by the model. These new maps agree significantly better with estimates from the steric-corrected altimetry, reducing the variance on average by 30% over 70% of the ocean. This is compared to smaller reductions over only 14% of the ocean using the 300-km Gaussian maps and 56% of the ocean using OMCT maps. The OMCT maps do not reduce variance as much in the Southern Ocean where OBP variations are largest, whereas the GRACE maps do. Based on this analysis, it is estimated that the local, or point-to-point, uncertainty of new EOF filtered maps of GRACE OBP is 1.3 (one standard deviation).
Temperature Measurements from Surface Drifters
Authors: Reverdin G. , Boutin J. , Martin N. , Lourenco A. , Bouruet-Aubertot P. , Lavin A. , Mader J. , Blouch P. , Rolland J. , Gaillard F. , Lazure P.
Published: July 2010

The accuracy of temperature measurements from drifters is first examined for 16 drifters (manufactured either by Metocean Data Systems or by Pacific Gyre) deployed with two temperature sensors in the tropical or North Atlantic Ocean. One of these sensors is the SST thermistor commonly used on Surface Velocity Program (SVP) drifters since the late 1980s; whereas the other sensor is a platinum temperature probe associated with a Seabird conductivity cell. The authors find (for 19 separate deployments) an average positive offset of the SST thermistor measurements in 17 out of 19 cases, exceeding 0.1°C in five instances. Among the five drifters that were at sea for a year or more, two present a large trend in this offset (0.10° and −0.10°C yr−1); and in two other cases, there is a clear annual cycle of the offset, suggesting a dependency on temperature. Offsets in 9 out of 12 drifters with sea time longer than 4 months present a negative trend, but the average trend is not significantly different from zero. The study also examined 29 drifters from four manufacturers equipped only with the usual SST thermistor, but for which either a precise initial temperature measurement was available or a float was attached to provide accurate temperature measurements (for a duration on the order of a month). These comparisons often identify SST biases at or soon after deployment. This initial bias is null (or slightly negative) for the set of Clearwater Instrumentation’s drifters, it is very small for two out of three sets of Technocean drifters, and positive for the third one, as well as for the set of Pacific Gyre drifters (on the order of 0.05°C).
Identifying Doppler Velocity Contamination Caused by Migrating Birds. Part I: Feature Extraction and Quantification
Authors: Zhang Pengfei , Liu Shun , Xu Qin
Published: July 2010

Radar echoes from migrating birds can severely contaminate Doppler velocity measurements. For meteorological applications, especially quantitative applications in radar data assimilation, it is necessary to remove bird-contaminated velocity scans by using an automated identification technique. Such a technique should be also useful for ornithologists in selecting bird echoes automatically from radar scans. This technique can be developed in two steps: (i) extract the main features of migrating-bird echoes from reflectivity and Doppler velocity images and find proper parameters to quantify these features; (ii) utilize these parameters to develop an automated quality control procedure to identify and flag migrating-bird-contaminated Doppler velocity scans (sweeps). The first step is accomplished in this study (Part I) by identifying possible migrating-bird echoes in the level II data collected from the Oklahoma KTLX radar during the 2003 spring migrating season. The identifications are further verified by polarimetric radar measurements from the National Severe Storms Laboratory (NSSL) KOUN radar, Geostationary Operational Environmental Satellite (GOES) IR images, and rawinsonde measurements. Three proper parameters are found, and their histograms are prepared for the second step of development (reported in Part II).
Identifying Doppler Velocity Contamination Caused by Migrating Birds. Part II: Bayes Identification and Probability Tests
Authors: Liu Shun , Xu Qin , Zhang Pengfei
Published: July 2010

Based on the Bayesian statistical decision theory, a probabilistic quality control (QC) technique is developed to identify and flag migrating-bird-contaminated sweeps of level II velocity scans at the lowest elevation angle using the QC parameters presented in Part I. The QC technique can use either each single QC parameter or all three in combination. The single-parameter QC technique is shown to be useful for evaluating the effectiveness of each QC parameter based on the smallness of the tested percentages of wrong decision by using the ground truth information (if available) or based on the smallness of the estimated probabilities of wrong decision (if there is no ground truth information). The multiparameter QC technique is demonstrated to be much better than any of the three single-parameter QC techniques, as indicated by the very small value of the tested percentages of wrong decision for no-flag decisions (not contaminated by migrating birds). Since the averages of the estimated probabilities of wrong decision are quite close to the tested percentages of wrong decision, they can provide useful information about the probability of wrong decision when the multiparameter QC technique is used for real applications (with no ground truth information).
Bioluminescence Intensity Modeling and Sampling Strategy Optimization*
Authors: Shulman I. , Kindle J. C. , McGillicuddy D. J. , Moline M. A. , Haddock S. H. D. , Nechaev D. , Phelps M. W.
Published: July 2010

The focus of this paper is on the development of methodology for short-term (1–3 days) oceanic bioluminescence (BL) predictions and the optimization of spatial and temporal bioluminescence sampling strategies. The approach is based on predictions of bioluminescence with an advection–diffusion–reaction (tracer) model with velocities and diffusivities from a circulation model. In previous research, it was shown that short-term changes in some of the salient features in coastal bioluminescence can be explained and predicted by using this approach. At the same time, it was demonstrated that optimization of bioluminescence sampling prior to the forecast is critical for successful short-term BL predictions with the tracer model. In the present paper, the adjoint to the tracer model is used to study the sensitivity of the modeled bioluminescence distributions to the sampling strategies for BL. The locations and times of bioluminescence sampling prior to the forecast are determined by using the adjoint-based sensitivity maps. The approach is tested with bioluminescence observations collected during August 2000 and 2003 in the Monterey Bay, California, area. During August 2000, BL surveys were collected during a strong wind relaxation event, while in August 2003, BL surveys were conducted during an extended (longer than a week) upwelling-favorable event. The numerical bioluminescence predictability experiments demonstrated a close agreement between observed and model-predicted short-term spatial and temporal changes of the coastal bioluminescence.
Assimilation of Wind Profiler Data in the Canadian Meteorological Centre’s Analysis Systems
Authors: St-James Judy S. , Laroche Stéphane
Published: July 2010

Real-time horizontal wind observations from the National Oceanic and Atmospheric Administration’s (NOAA’s) Profiler Network (NPN) are assessed in preparation for their assimilation in the Canadian Meteorological Centre (CMC) analysis systems. As a first step, radiosonde winds from 20 stations were compared to the central U.S. profiler stations over the 2001/02 winter season. It was found that profilers are at least as good as conventional radiosonde data. The 2001/02 winter season data were also used to examine the vertical correlation structure of the observation error for profilers. Using a statistical analysis of innovations, the observation error standard deviation of the wind components is estimated as 2.2 m s−1 and the vertical correlation length is approximately 500 m. These results suggest that the data are vertically correlated because they are available every 250 m. Therefore, a thinning process is proposed in which one out of three data are selected in the vertical for each station.

Since January 2004, a close monitoring of NPN profiler data revealed significant errors at some stations in the lower and upper troposphere. Consequently, a monthly blacklist of NPN profilers is built based on data from the previous month.

A data impact study with both the three-dimensional variational data assimilation (3DVAR) and four-dimensional variational data assimilation (4DVAR) analysis systems was conducted using data from the 2003/04 winter season in which the vertical thinning was tested. It was found that the vertical thinning improves slightly the 6-h forecast error, especially in the 4DVAR over the central United States in which 6 times more profilers are assimilated. The impact of the vertical thinning is found to be neutral in the 3DVAR. Also, the impact of profiler data is significant over the central U.S. domain compared to a control run with the only difference being the addition of profiler data. These results were sufficiently good to implement NPN profilers in both the CMC global and regional analysis systems with the thinning process in fall of 2004.
Stratocumulus Liquid Water Content from Dual-Wavelength Radar
Authors: Hogan Robin J. , Gaussiat Nicolas , Illingworth Anthony J.
Published: July 2010

A technique is described to retrieve stratocumulus liquid water content (LWC) using the differential attenuation measured by vertically pointing radars at 35 and 94 GHz. Millimeter-wave attenuation is proportional to LWC and increases with frequency, so LWC can be derived without the need to make any assumptions on the nature of the droplet size distribution. There is also no need for the radars to be well calibrated. A significant advantage over many radar techniques in stratocumulus is that the presence of drizzle drops (those with a diameter larger than around 50 μm) does not affect the retrieval, even though such drops may dominate the radar signal. It is important, however, that there are not significant numbers of drops larger than 600 μm, which scatter outside of the Rayleigh regime at 94 GHz. A lidar ceilometer is used to locate the cloud base in the presence of drizzle falling below the cloud. An accuracy of around 0.04 g m−3 is achievable with averaging over 1 min and 150 m (two range gates), but for the previously suggested frequency pair of 10 and 35 GHz, the corresponding accuracy would be considerably worse at 0.34 g m−3. First, the retrieval of LWC is simulated using aircraft-measured size spectra taken from a profile through marine stratocumulus. Results are then presented from two case studies—one using two cloud radars at Chilbolton in southern United Kingdom, and another using the Cloud Profiling Radar System at the Atmospheric Radiation Measurement site in Oklahoma. The liquid water path from the technique was found to be in good agreement with the values that were obtained from microwave radiometers, with the difference between the two being close to the accuracy of the radiometer retrieval. In the case of well-mixed stratocumulus, the profiles were close to adiabatic.
Compact and Low-Power Diode Laser Hygrometer for Weather Balloons
Authors: Paige M. E.
Published: July 2010

A vertical cavity laser hygrometer has been developed for balloon-borne measurements. This hygrometer meets many of the specifications that are required for common weather balloon instrumentation, including weight, size, time response, and sensitivity. In addition, the system cost has been dramatically lowered relative to prior diode laser instruments. Sensitivity of 2 and 0.9 μbar at low- and high-altitude conditions, respectively, has been obtained in a 1-s measurement period, with the strong possibility of improved performance in the near future. The engineering advances that are demonstrated by this system make balloon-borne diode laser hygrometry a practical technique for more frequent use.
Calibration Issues of Dual-Polarization Radar Measurements
Authors: Ryzhkov Alexander V. , Giangrande Scott E. , Melnikov Valery M. , Schuur Terry J.
Published: July 2010

Techniques for the absolute calibration of radar reflectivity Z and differential reflectivity ZDR measured with dual-polarization weather radars are examined herein.

Calibration of Z is based on the idea of self-consistency among Z, ZDR, and the specific differential phase KDP in rain. Extensive spatial and temporal averaging is used to derive the average values of ZDR and KDP for each 1 dB step in Z. Such averaging substantially reduces the standard error of the KDP estimate so the technique can be used for a wide range of rain intensities, including light rain.

In this paper, the performance of different consistency relations is analyzed and a new self-consistency methodology is suggested. The proposed scheme substantially reduces the impact of variability in the drop size distribution and raindrop shape on the quality of the Z calibration. The new calibration technique was tested on a large polarimetric dataset obtained during the Joint Polarization Experiment in Oklahoma and yielded an accuracy of Z calibration within 1 dB.

Absolute calibration of ZDR is performed using solar measurements at orthogonal polarizations and polarimetric properties of natural targets like light rain and dry aggregated snow that are probed at high elevation angles. Because vertical sounding is prohibited for operational Weather Surveillance Radar-1988 Doppler (WSR-88D) radars because of mechanical constraints, the existing methodology for ZDR calibration is modified for nonzenith elevation angles. It is shown that the required 0.1–0.2-dB accuracy of the ZDR calibration is potentially achievable.
Passive Acoustic Detection and Measurement of Rainfall at Sea
Authors: Ma Barry B. , Nystuen Jeffrey A.
Published: July 2010

Rainfall over the ocean is one of the most important climatic parameters for both oceanic and atmospheric science. Traditional accumulation-type rain gauges are difficult to operate at sea, and so an alternate technique using underwater sound has been developed. The technique of passive monitoring of the ocean rainfall using ambient sound depends on the accuracy of sound pressure level (SPL) detection. Consequently, absolute calibration of the hydrophone is desirable, but is difficult to achieve because typically the geometry of the laboratory calibration process does not fit the measurement geometry over the ocean. However, if one assumes that the sound signal that is generated by wind is universal then the wind signal can be used to provide an absolute calibration. Over 90 buoy months of ambient sound spectra have been collected on the Tropical Atmosphere Ocean (TAO) project array since 1998. By applying the Vagle et al. wind speed algorithm, the instrument noises and sensitivity bias for the absolute calibration of each acoustic rain gauge (ARG) are obtained. An acoustic discrimination process is developed to retrieve the pure geophysical signals. A new single-frequency rainfall-rate algorithm is proposed after comparing the ARG data with R.M. Young self-siphoning rain gauge data, collocated on the same moorings. The acoustic discrimination process and the rainfall algorithm are further tested at two other locations and are compared with R.M. Young rain gauges and the Tropical Rain Measuring Mission (TRMM) product 3B42. The acoustic rainfall accumulations show the comparable results in both long (year) and short (hours) time scales.
A Multi-Index GEM Technique and Its Application to the Southwestern Japan/East Sea
Authors: Park Jae-Hun , Watts D. Randolph , Tracey Karen L. , Mitchell Douglas A.
Published: July 2010

This paper demonstrates a new gravest empirical mode (GEM) technique that constructs multi-index lookup tables of temperature (T) and specific volume anomalies (δ) using historical hydrocasts as a function of three indices: round-trip travel time (τ) from sea floor to the surface, sea surface temperature, and pressure. Moreover, the historical hydrocasts are separated into non-mixed-layer (NML) and mixed-layer (ML) groups, and a single GEM field is constructed for each group. This is called the MI-GEM technique. The appropriate dates for MI-GEM fields are determined by the monthly distribution of the number of NML and ML profiles in the historical hydrocasts, which are also well correlated with the strength of the winds during the 2 yr of observations. The T and δ profiles that are determined by this MI-GEM technique capture 92% and 88% of the T and δ variances in the depth range of 0–200 db. These values reduce by about one-third of the unexplained error variance of the residual GEM, which was recently developed and applied to the optimal interpolated τ data in the southwestern Japan/East Sea (JES) by Mitchell et al. Comparisons with the in situ CTD casts demonstrate that the MI-GEM technique almost always produces improved full water column profiles of T and δ. Whereas the residual GEM estimates had exhibited qualitatively erroneous features like T inversions in the near–surface layer and too thin or thick intermediate water layers in some regions, the MI-GEM estimates avoid those problems, which were inherent to the residual GEM technique in the southwestern JES.
An ultra-wideband impulse radio PHY layer model for network simulation
Authors: Rousselot Jérôme , Decotignie Jean-Dominique
Published: July 2010

This paper presents a novel modeling technique of Ultra-Wideband Impulse Radio for the simulation of wireless sensor networks, to evaluate this technology from a systems point of view that includes the effect of communication protocols. The adopted approach, named Maximum Pulse Amplitude Estimation, considers the characteristics of the propagation channel, the transmitter and receiver architectures, the modulation type, the robustness to multiple access interference and the impact of error correction coding. It differs from the state of the art by working at the symbol level instead of developing an analytical model. While this technique increases the processing time, it offers more flexibility in terms of modulations, channel models and receiver architecture. Our approach enabled us to implement the first network simulation model of the UWB PHY specified in the IEEE 802.15.4A standard. It is also the first UWB-IR network simulation model to consider an energy detection receiver. Several channel models have been implemented, offering trade-offs between simulation speed and accuracy. The performance of this energy detection transceiver is compared with MATLAB models. The packet error rate is evaluated as a function of distance with several channel models, and in the presence of interferers. It is shown that our approach leads to results in line with MATLAB models, that the choice of channel model greatly impacts the simulation speed and that the IEEE 802.15.4A UWB PHY allows some limited degree of protection against multiple access interference even when using a low performance energy detection receiver architecture.
When flexibility diversity becomes socially acceptable: The case of the French hospital industry
Authors: Mossé Philippe , Méhaut Philippe , Arborio Anne-Marie , Causse Lise
Published: July 2010

The aim of this article, which is mostly based on case studies of public and private French hospitals, is to analyse the employment of nurse assistants (NA) and unqualified health care workers ( agent des services hospitaliers or ASH), focusing particularly on questions of flexibility. First, the article shows that in French hospitals, the cleaning and basic health care tasks are performed by a relatively stable core group of employees and by a more flexible workforce. From the hospital perspective, the need for flexibility is related to the growing trend towards rationalization. But employees see the demands for flexibility from a different angle, depending on their professional histories. The article also shows that the nurse assistants and unqualified health care workers who work under these unstable conditions may see this situation as a transition period and as a gateway to permanent jobs. Consequently, and despite the difficult working conditions, the job opportunities offered by hospitals may be attractive to women with few or no qualifications.
Mind-mindedness in adult and adolescent mothers: Relations to maternal sensitivity and infant attachment
Authors: Demers Isabelle , Bernier Annie , Tarabulsy George M. , Provost Marc A.
Published: July 2010

This article examines the quality of maternal mind-mindedness among adult and adolescent mothers, using an assessment of the appropriateness and emotional valence of maternal mind-related comments while interacting with their infants. Twenty-nine adult mothers and 69 adolescent mothers participated in two assessments with their 18-month-old infants. Results showed that adult mothers used more mind-related comments when interacting with their child, especially comments referring to infant mental states. Adult mothers also used more appropriate and positive mind-related comments. Home observations and strange situation assessments revealed that two dimensions of mind-mindedness were associated with maternal sensitivity and three with infant attachment in adult mothers, whereas only one dimension was associated with maternal sensitivity in adolescent mothers.
Gender and Entrepreneurship as a Career Choice
Authors: Thébaud Sarah
Published: July 2010

The gender gap in entrepreneurship has typically been understood through women’s structural disadvantages in acquiring the resources relevant for successful business ownership. This study builds on resource-based approaches to investigate how cultural beliefs about gender influence the process by which individuals initially come to identify entrepreneurship as a viable labor-market option. Drawing on status characteristics theory, this study evaluates (1) how cultural beliefs about gender and entrepreneurship influence self-assessments of entrepreneurial ability, and (2) the extent to which such assessments account for the gender gap in business start-ups. Results suggest that women are significantly less likely to perceive themselves as able to be an entrepreneur and they hold themselves to a stricter standard of competence when compared to similarly situated men. This gender difference in self-assessments accounts for a significant portion of the gender gap in entrepreneurship after controlling for relevant resources. Additional analyses reveal that significant gender differences in self-assessed ability persist among established business owners.
Anemia Evaluation and Management in Nursing Home Residents
Authors: Sabol Valerie K. , Resnick Barbara , Galik Elizabeth , Gruber-Baldini Ann L. , Gonce Morton Patricia , Hicks Gregory E.
Published: August 2010

Anemia is often an unrecognized and/or undertreated diagnosis in older adults. Failure to diagnose anemia leads to delayed treatment and thus delayed relief of symptoms. Given the potentially significant impact of anemia on cardiovascular disease and physical performance among older nursing home (NH) residents, it is important to evaluate current clinical practice related to anemia.The purpose of this secondary data analysis was to evaluate the frequency of laboratory evaluation and medication treatment for anemia among older NH residents. Results indicated that more than half of NH residents were anemic at baseline, and of those, less than 20% had additional testing done to further evaluate for an underlying cause of their anemia and only 45.3% received any pharmacologic treatment. Future research is needed to clarify the potential benefits of timely diagnosis and appropriate treatment for anemic older adults in long-term-care settings and establish evidence-based guidelines to direct care in this area.
IQ Scores Should Not Be Adjusted for the Flynn Effect in Capital Punishment Cases
Authors: Hagan Leigh D. , Drogin Eric Y. , Guilmette Thomas J.
Published: July 2010

Atkins v. Virginia (2002) dramatically raised the stakes for mental retardation in capital punishment cases, but neither defined this condition nor imposed uniform standards for its assessment. The basic premise that mean IQ scores shift over time enjoys wide recognition, but its application— including the appropriateness of characterizing it in terms of an allegedly predictable “Flynn effect”— is frequently debated in the course of death penalty litigation. The scientifically and ethically sound approach to this issue is to report IQ scores as obtained and be prepared to address those factors that might affect their reliability. Altering the IQ scores themselves is insufficiently supported by professional literature, legal authority, or prevailing standards of practice.
Trait Emotional Intelligence and Academic Performance: Controlling for the Effects of IQ, Personality, and Self-Concept
Authors: Ferrando Mercedes , Prieto María Dolores , Almeida Leandro S. , Ferrándiz Carmen , Bermejo Rosario , López-Pina José Antonio , Hernández Daniel , Sáinz Marta , Fernández Mari-Carmen
Published: July 2010

This article analyses the relationship between trait emotional intelligence and academic performance, controlling for the effects of IQ, personality, and self-concept dimensions. A sample of 290 preadolescents (11-12 years old) took part in the study. The instruments used were (a) Trait Emotional Intelligence Questionnaire—Adolescents Short Form (TEIQue-ASF); (b) Children’s Personality Questionnaire (CPQ; Form A, Part A); (c) IQ test TIDI-2; (d) Adaptation Questionnaire (CAI-1); and (e) academic performance. A positive and significant correlation coefficient between trait EI measured by the TEIQue-ASF and general academic performance was found. The TEIQue-ASF showed incremental validity to predict general academic performance, after controlling for intelligence, personality, and self-concept characteristics.
Creating Composite Age Groups to Smooth Percentile Rank Distributions of Small Samples
Authors: López Francesca , Olson Amy , Bansal Naveen
Published: July 2010

Individually administered tests are often normed on small samples, a process that may result in irregularities within and across various age or grade distributions. Test users often smooth distributions guided by Thurstone assumptions (normality and linearity) to result in norms that adhere to assumptions made about how the data should look. Test users, however, may come across particular tests or sets of data in which the Thurstone assumptions are untenable. When users expect deviations from normality within age or grade, an alternate method is desirable. The authors present a relatively simple procedure that allows the user to treat observed raw scores as ordinal data with differently shaped sample distributions across age levels. Each age-level group is used twice to create new moving composite group distributions that replace (i.e., smooth) the original groups to reduce irregularities due to the small sample sizes. The authors present the results of a simulation study of the method, demonstrating that moving composite groups ameliorate error introduced by small samples beyond applying the normalized inverse to a score distribution. The method presented might satisfy those who question whether their data meet the strong assumptions of normality and interval-level measurement, and the simplicity might encourage smoothing by additional users.
A Review of Psychometric Assessment and Reporting Practices: An Examination of Measurement-Oriented Versus Non-Measurement-Oriented Domains
Authors: Slaney Kathleen L. , Tkatchouk Masha , Gabriel Stephanie M. , Ferguson Leona P. , Knudsen Jared R. S. , Legere Julien C.
Published: July 2010

The primary aim of the present study is to determine whether the psychometric evaluation practices and test-analytic rationales of researchers publishing in journals with a measurement focus differ from those of researchers publishing in journals with varying substantive research foci. Several components of two different samples of articles were examined and compared; one contained articles from a set of measurement-oriented journals ( n = 402) and the other contained articles published in journals representing a cross-section of research domains ( n = 289). Findings indicate that, contrary to expectations, articles published in measurement-oriented journals, as compared with general journals, generally may not reflect better psychometric analysis and reporting practices or sounder test-analytic rationales on the part of the researchers. It was also found that although researchers are generally evaluating either score precision/reliability or validity, they seldom evaluate both, indicating that there may be a general lack of appreciation for the importance of conducting a full and coherent data-based test analysis whenever a measure is employed. A number of limitations of the study and recommendations for future research are also addressed.
School-Based Intervention: Relaxation and Guided Imagery for Students With Asthma and Anxiety Disorder
Authors: Vineeta Gandotra Kapoor  , Bray Melissa A. , Kehle Thomas J.
Published: July 2010

This school-based study analyzed the impact of RGI on lung functioning (forced expiratory volume in 1 s [FEV1] and forced expiratory flow 25-75 [FEF25-75]) and by employing a multiple baseline design across 3 high school students with asthma and clinically diagnosed anxiety disorders. The RGI intervention took place for a 20-min period, an average of three times per week, over a 4-week period. At the onset of the intervention, it was found that lung functioning, particularly FEV1 increased in all 3 participants, with effect sizes ranging from —.32 to —2.48. FEF25-75 improved in one of the participants. In addition, a positive impact was also seen in the lowering of anxiety scores across all 3 participants, with effect sizes ranging from .12 to 1.69.
An Economic Industry and Institutional Level of Analysis of Corporate Social Responsibility Communication
Authors: O'Connor Amy , Shumate Michelle
Published: July 2010

This study identifies the similarities and differences in corporate social responsibility (CSR) communication at the institutional and economic industry level of analysis. Findings suggest that at the institutional level of analysis, a corporate consensus exists about the scope of CSR and is largely understood as welfare capitalism. However, at the economic level of analysis, differences across economic industries exist based on value-chain position. Specifically, industries further up the value-chain focus on the safety of their employees, ethical business practices, and environmental stewardship as essential elements of CSR, whereas economic industries closer to customers in the value chain were more likely to focus on philanthropy and education as CSR.
Making a Case for Acute Ischemic Stroke
Authors: Baldwin Kathleen A. , McCoy Stacey L.
Published: August 2010

Stroke is the third leading cause of death in the United States and the number one cause of adult long-term disability. Disability in stroke survivors includes hemiparesis, aphasia, inability to walk without assistance, dependence on others for activities of daily living, depression, and institutionalization. Immediate recognition of acute ischemic stroke (AIS) signs and symptoms is required because many treatment options are time sensitive. Hospital transport via activation of 911 and emergency medical services (EMSs) removes delays to urgent diagnosis and intervention. Intravenous (IV) recombinant tissue plasminogen (rt-PA) is a time-sensitive reperfusion strategy. The American Heart Association (AHA) and American Stroke Association (ASA) recently revised recommendations that the time window for IV rt-PA be expanded from 3 hours to 4.5 hours after symptom onset in patients with mild to moderate stroke. Supportive therapies include crystalloid IV solutions, adequate oxygenation, and normothermia. Best rest is desired along with oxygen supplementation. Avoidance of fever is paramount since fever can contribute to negative outcomes. It is the purpose of this article to review risk factors, stroke symptoms, epidemiology, and current drug therapy of AIS. Standards of care will be reviewed.
Finding a Balance
Authors: Eastlick Kushner Kaysi , Harrison Margaret J.
Published: July 2010

Purpose: We investigated how mothers employed in support staff positions make personal and family health decisions. Design: We used a critical feminist grounded theory design. Methods: Twenty women employed at a large Canadian institution participated over two years in repeat interactive interviews. Findings: “Finding a balance” was the emergent core process of health decision making in response to the basic social problem of multiple demands and uncoordinated, sometimes conflicting ideologies. Women emphasized recursive movement within a continuous process of four action phases: cueing in, figuring out, generating solutions, and assessing results. Two distinct views of finding a balance were revealed: weighing competing interests or harmonizing multiple interests. These distinctive views contributed to variation in women’s approaches to decision making and to their personal and family health experiences. Conclusions: Women’s experiences suggest a capacity for reflective practice in health decision making that provides an excellent basis for holistic, emancipatory nursing practice.
Using Institutional Ethnography to Understand the Production of Health Care Disparities
Authors: Sinding Christina
Published: July 2010

Questions of health care access and equity are often examined by researchers using quantitative approaches, describing patterns of service utilization. Articles based on such approaches often reveal relatively little about how health care services and resources come to be distributed as they are. Articles about qualitative research with marginalized people, although offering textured accounts of people’s experiences of care, often do not systematically link felt troubles to specific features of health systems. Institutional ethnography, a method of inquiry developed over the past 25 years by Canadian sociologist Dorothy Smith and her colleagues, offers a useful resource for researchers exploring and addressing health care disparities. Drawing on previous research and a study in progress on cancer care in Ontario, Canada, I consider the potential of institutional ethnography to make visible how disparities are produced in the routine operation of health services.
Everyday Nursing Practice Values in the NICU and Their Reflection on Breastfeeding Promotion
Authors: Cricco-Lizza Roberta
Published: August 2010

In this ethnographic study I examined neonatal intensive care unit (NICU) nurses’ everyday practice values and explored how breastfeeding promotion fit within this context. The study was conducted over a 14-month period and included participant observation and interviewing of 114 purposively selected nurses in a level-IV NICU in the United States. Uncertainty emerged as a central concern underlying everyday practice values. Three themes described these values: (a) maximizing babies’ potentials in the midst of uncertainty; (b) relying on the sisterhood of NICU nurses to deal with uncertainty; and (c) confronting uncertainty through tight control of actions, reliance on technology, and maximal efficiency in use of time. A fourth theme demonstrated how these values were reflected in NICU breastfeeding practices. Although high-control, high-tech, and time-urgent practice values were helpful in confronting uncertainty, these values also posed challenges to ongoing nursing efforts to promote breastfeeding. These values must be addressed for effective breastfeeding promotion.