bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinct Modes of the East Asian Winter Monsoon
Authors: Wu Bingyi , Zhang Renhe , D’Arrigo Rosanne
Published: August 2006

Two distinct modes of the East Asian winter monsoon (EAWM) have been identified, and they correspond to real and imaginary parts of the leading mode of the EAWM, respectively. Analyses of these modes used the National Centers for Environment Prediction (NCEP) and National Center for Atmospheric Research (NCAR) monthly mean reanalysis datasets for the period 1968–2003, as well as the Southern Oscillation index (SOI), North Atlantic Oscillation index, and eastern equatorial Pacific sea surface temperature (SST) data. Results were obtained by resolving a complex Hermite matrix derived from 850-hPa anomalous wind fields, and determining the resulting modes’ associations with several climate variables. The first distinct mode (M1) is characterized by an anomalous meridional wind pattern over East Asia and the western North Pacific. Mode M1 is closely related to several features of the atmospheric circulation, including the Siberian high, East Asian trough, East Asian upper-tropospheric jet, and local Hadley circulation over East Asia. Thus, M1 reflects the traditional EAWM pattern revealed in previous studies. The second distinct EAWM mode (M2), which was not identified previously, displays dominant zonal wind anomalies over the same area. Mode M2 exhibits a closer relation than M1 to sea level pressure anomalies over the northwestern Pacific southeast of Japan and with the SOI and equatorial eastern Pacific SST. Unlike M1, M2 does not show coherent relationships with the Siberian high, East Asian trough, and East Asian upper-tropospheric jet. Since atmospheric circulation anomalies relevant to M2 exhibit a quasi-barotropic structure, its existence cannot simply be attributed to differential land–sea heating. El Niño events tend to occur in the negative phase of M1 and the positive phase of M2, both corresponding to a weakened EAWM. The Arctic Oscillation does not appear to impact the EAWM on interannual time scales. Although the spatial patterns for the two modes are very different, the two distinct modes are complementary, with the leading EAWM mode being a linear combination of the two. The results herein therefore demonstrate that a single EAWM index may be inappropriate for investigating and predicting the EAWM.
Serial Clustering of Extratropical Cyclones
Authors: Mailier Pascal J. , Stephenson David B. , Ferro Christopher A. T. , Hodges Kevin I.
Published: August 2006

The clustering in time (seriality) of extratropical cyclones is responsible for large cumulative insured losses in western Europe, though surprisingly little scientific attention has been given to this important property. This study investigates and quantifies the seriality of extratropical cyclones in the Northern Hemisphere using a point-process approach. A possible mechanism for serial clustering is the time-varying effect of the large-scale flow on individual cyclone tracks. Another mechanism is the generation by one “parent” cyclone of one or more “offspring” through secondary cyclogenesis. A long cyclone-track database was constructed for extended October–March winters from 1950 to 2003 using 6-h analyses of 850-mb relative vorticity derived from the NCEP–NCAR reanalysis. A dispersion statistic based on the variance-to-mean ratio of monthly cyclone counts was used as a measure of clustering. It reveals extensive regions of statistically significant clustering in the European exit region of the North Atlantic storm track and over the central North Pacific. Monthly cyclone counts were regressed on time-varying teleconnection indices with a log-linear Poisson model. Five independent teleconnection patterns were found to be significant factors over Europe: the North Atlantic Oscillation (NAO), the east Atlantic pattern, the Scandinavian pattern, the east Atlantic–western Russian pattern, and the polar–Eurasian pattern. The NAO alone is not sufficient for explaining the variability of cyclone counts in the North Atlantic region and western Europe. Rate dependence on time-varying teleconnection indices accounts for the variability in monthly cyclone counts, and a cluster process did not need to be invoked.
Synoptic and Topographic Variability of Northern California Precipitation Characteristics in Landfalling Winter Storms Observed during CALJET
Authors: Kingsmill David E. , Neiman Paul J. , Ralph F. Martin , White Allen B.
Published: August 2006

Observations from northern California during the California Landfalling Jets (CALJET) experiment are used to examine the mean characteristics of precipitation and their variances as functions of synoptic and topographic regimes. Ten cases involving the landfall of extratropical cyclones are analyzed with radar and rain gauge data collected at two sites: one in the coastal mountains north of San Francisco (CZD) and the other in the Central Valley just west of Sacramento (KDAX). Aside from the melting-layer bright band, the most striking feature in the 10-case composite vertical profile of radar reflectivity at CZD was a distinct change in slope about 2.5 km above the bright band. This “shoulder” is thought to represent a change in the growth rate of hydrometeors. Although the bright band was quite distinct, about one-third of the profiles in the composite did not exhibit this feature. These nonbrightband (NBB) profiles had a low-level slope where reflectivity increased with decreasing altitude, a structure suggesting that collision–coalescence was the primary growth process. The relationship between surface rainfall rate and low-level radar reflectivity implies that all profiles were composed of larger numbers of small drops than expected from a Marshall–Palmer drop size distribution, a trend that was especially apparent for NBB profiles.

Synoptic variability of precipitation characteristics at CZD were examined by identifying five distinct regimes (cold sector, warm front, warm sector, cold front, and cool sector) based on a simplified conceptual model. The shoulder remained approximately 2.5 km above the bright band in each regime. Rainfall intensity was highest during the cold-frontal regime and NBB rainfall was most common during the warm-frontal, warm-sector, and cool-sector regimes. Topographic variability of precipitation characteristics was investigated by comparing results at CZD and KDAX. A shoulder structure located about 2.5 km above the bright band was also evident in the KDAX profiles, suggesting that this feature is related to large-scale dynamic, thermodynamic, and microphysical processes rather than orographic effects. The relationship between surface rainfall rate and low-level radar reflectivity near KDAX closely followed a trend expected for a Marshall–Palmer drop size distribution, implying the presence of relatively larger raindrops than observed at CZD and indicating that NBB rainfall occurs less frequently near KDAX.
Multiply Nested Regional Climate Simulation for Southern South America: Sensitivity to Model Resolution
Authors: Rojas Maisa
Published: August 2006

Results are reported from two 5-month-long simulations for southern South America using the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5). The periods of simulation correspond to May–September 1997 and 1998, which were anomalously wet and dry winters for central Chile, respectively. The model setup includes triply nested, two-way-interacting domains centered over the eastern South Pacific and the western coast of southern South America, with horizontal grid intervals of 135, 45, and 15 km. Boundary conditions are provided from NCEP–NCAR reanalyzed fields. The analysis focuses on two subregions of central Chile (30°–41°S). Region 1 (32°–35°S), which is where the observed interannual precipitation differences are largest, is topographically very complex, with a mean height of the Andes Cordillera around 4500 m. Region 2 (35°–39°S) has relatively smooth terrain, as the mean height of the Andes drops to 3000 m. Station precipitation and temperature data are used for model validation. The model exhibits a negative temperature bias (from 2° to 5°C), as well as a positive precipitation bias (40%–80%). This precipitation bias can be partially explained by a positive moisture bias over the ocean in the model. In addition, these biases are highly correlated to the representation of terrain and station elevation in the model. The highest-resolution domain has the smallest precipitation bias for low-elevation stations, but a large positive bias at high altitudes (up to 300%). It also has a better representation of the spatial distribution of the precipitation, especially in region 1, where topography has a larger impact on the precipitation. Overall, the model domain with highest resolution best reproduces the observed precipitation and temperature, as well as the interannual differences. However, this study also shows that large improvements in the simulations of the surface variables are obtained when downscaling from 135 to 45 km, but much smaller improvements are found when downscaling from 45 to 15 km. These simulations represent the first effort in simulating seasonal precipitation in this topographically complex region of the Southern Hemisphere.
Positive-Definite and Monotonic Limiters for Unrestricted-Time-Step Transport Schemes
Authors: Skamarock William C.
Published: August 2006

General positive-definite and monotonic limiters are described for use with unrestricted-Courant-number flux-form transport schemes. These limiters are tested using a time-split multidimensional transport scheme. The importance of minimizing the splitting errors associated with the time-split operator and of the consistency between the transport scheme and the discrete continuity equation is demonstrated.
Mechanisms of the Northward Movement of Submonthly Scale Vortices over the Bay of Bengal during the Boreal Summer
Authors: Yokoi Satoru , Satomura Takehiko
Published: August 2006

Mechanisms of the northward movement of submonthly scale vortices over the Bay of Bengal during the boreal summer (May–September) are studied with the use of a vorticity budget analysis applied to the ECMWF 40-yr Re-Analysis (ERA-40) data. To quantitatively evaluate the contribution from each term that constitutes the vorticity anomaly equation to the movement of the vortices, a vector measure, termed the forcing vector (FV), is used in the present study. Because the axis of the submonthly scale relative vorticity anomaly does not tilt meridionally below the 200-hPa level, the mechanisms of the northward movement of a composite submonthly scale vortex integrated from the surface to the 100-hPa level [the barotropic component (BTC)] are studied. The barotropic vortex moves northwestward, with northward speeds of 0.9° day−1. The meridional component of the FV (MFV), which represents the contribution to the meridional component of the movement, reveals that the primary and secondary terms that contribute to the northward movement are the advection of the vortex by the environmental meridional wind, and the tilting effect of the environmental horizontal vorticity vector by the vertical pressure velocity anomaly associated with the vortex, respectively. The former term works mainly in the lower troposphere, while the latter operates in the middle and upper troposphere. The first baroclinic component (FBCC) of the vortex in the troposphere also moves northwestward with almost the same northward speed as the BTC. Mechanisms of the northward movement of the FBCC are also clarified in the present study through examination of the MFV. The primary contributing term is the same as that of the BTC, while the tilting term hinders the northward movement of the FBCC. For the FBCC, the secondary contributing term is the advection of the planetary vorticity by the meridional wind anomaly associated with the horizontal convergence and divergence anomalies in the lower and upper troposphere, respectively. The present study also discusses the phase relation between the BTC and the FBCC from the viewpoint of their northward movement in an environment of easterly vertical shear.
Improving Week-2 Forecasts with Multimodel Reforecast Ensembles
Authors: Whitaker Jeffrey S. , Wei Xue , Vitart Frédéric
Published: August 2006

It has recently been demonstrated that model output statistics (MOS) computed from a long retrospective dataset of ensemble “reforecasts” from a single model can significantly improve the skill of probabilistic week-2 forecasts (with the same model). In this study the technique is extended to a multimodel reforecast dataset consisting of forecasts from ECMWF and NCEP global models. Even though the ECMWF model is more advanced than the version of the NCEP model used (it has more than double the horizontal resolution and is about five years newer), the forecasts produced by the multimodel MOS technique are more skillful than those produced by the MOS technique applied to either the NCEP or ECMWF forecasts alone. These results demonstrate that the MOS reforecast approach yields benefits for week-2 forecasts that are just as large for high-resolution state-of-the-art models as they are for relatively low resolution out-of-date models. Furthermore, operational forecast centers can benefit by sharing both retrospective reforecast datasets and real-time forecasts.
Predictability Mysteries in Cloud-Resolving Models
Authors: Hohenegger Cathy , Lüthi Daniel , Schär Christoph
Published: August 2006

The rapid amplification of small-amplitude perturbations by the chaotic nature of the atmospheric dynamics intrinsically limits the skill of deterministic weather forecasts. In this study, limited-area cloud-resolving numerical weather prediction (NWP) experiments are conducted to investigate the role of mesoscale processes in determining predictability. The focus is set on domain-internal error growth by integrating an ensemble of simulations using slightly modified initial conditions but identical lateral boundary conditions. It is found that the predictability of the three investigated cases taken from the Mesoscale Alpine Programme (MAP) differs tremendously. In terms of normalized precipitation spread, values between 0.05 (highly predictable) and 1 (virtually unpredictable) are obtained. Analysis of the derived ensemble spread demonstrates that the diabatic forcing associated with moist dynamics is the prime source of rapid error growth. However, in agreement with an earlier study it is found that the differentiation between convective and stratiform rain is unable to account for the distinctive precipitation spreads of the three cases. In particular, instability indices are demonstrated to be poor predictors of the predictability level. An alternate hypothesis is proposed and tested. It is inspired by the dynamical instability theory and states that significant loss of predictability only occurs over moist convectively unstable regions that are able to sustain propagation of energy against the mean flow. Using a linear analysis of gravity wave propagation, this hypothesis is shown to provide successful estimates of the predictability level for the three cases under consideration.
Sensitivity of the Tropospheric Circulation to Changes in the Strength of the Stratospheric Polar Vortex
Authors: Jung Thomas , Barkmeijer Jan
Published: August 2006

The sensitivity of the wintertime tropospheric circulation to changes in the strength of the Northern Hemisphere stratospheric polar vortex is studied using one of the latest versions of the ECMWF model. Three sets of experiments were carried out: one control integration and two integrations in which the strength of the stratospheric polar vortex has been gradually reduced and increased, respectively, during the course of the integration. The strength of the polar vortex is changed by applying a forcing to the model tendencies in the stratosphere only. The forcing has been obtained using the adjoint technique. It is shown that, in the ECMWF model, changes in the strength of the polar vortex in the middle and lower stratosphere have a significant and slightly delayed (on the order of days) impact on the tropospheric circulation. The tropospheric response shows some resemblance to the North Atlantic Oscillation (NAO), though the centers of action are slightly shifted toward the east compared to those of the NAO. Furthermore, a separate comparison of the response to a weak and strong vortex forcing suggests that to first order the tropospheric response is linear within a range of realistic stratospheric perturbations. From the results presented, it is argued that extended-range forecasts in the European area particularly benefit from the stratosphere–troposphere link.
On the Use of QuikSCAT Scatterometer Measurements of Surface Winds for Marine Weather Prediction
Authors: Chelton Dudley B. , Freilich Michael H. , Sienkiewicz Joseph M. , Von Ahn Joan M.
Published: August 2006

The value of Quick Scatterometer (QuikSCAT) measurements of 10-m ocean vector winds for marine weather prediction is investigated from two Northern Hemisphere case studies. The first of these focuses on an intense cyclone with hurricane-force winds that occurred over the extratropical western North Pacific on 10 January 2005. The second is a 17 February 2005 example that is typical of sea surface temperature influence on low-level winds in moderate wind conditions in the vicinity of the Gulf Stream in the western North Atlantic. In both cases, the analyses of 10-m winds from the NCEP and ECMWF global numerical weather prediction models considerably underestimated the spatial variability of the wind field on scales smaller than 1000 km compared with the structure determined from QuikSCAT observations. The NCEP and ECMWF models both assimilate QuikSCAT observations. While the accuracies of the 10-m wind analyses from these models measurably improved after implementation of the QuikSCAT data assimilation, the information content in the QuikSCAT data is underutilized by the numerical models. QuikSCAT data are available in near–real time in the NOAA/NCEP Advanced Weather Interactive Processing System (N-AWIPS) and are used extensively in manual analyses of surface winds. The high resolution of the QuikSCAT data is routinely utilized by forecasters at the NOAA/NCEP Ocean Prediction Center, Tropical Prediction Center, and other NOAA weather forecast offices to improve the accuracies of wind warnings in marine forecasts.
Maintenance of a Mountain Valley Cold Pool: A Numerical Study
Authors: Billings Brian J. , Grubišić Vanda , Borys Randolph D.
Published: August 2006

A persistent cold-air pool in the Yampa Valley of northwestern Colorado was simulated with the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5). The observed cold-air pool, which was identified by temperature measurements along a line of surface stations ascending the eastern side of the valley, remained in place throughout the day of 10 January 2004. The baseline simulation with horizontal resolution of 1 km, which is close to the resolution of operational regional mesoscale model forecasts, neither matched the strength of the observed cold-air pool nor retained the cold pool throughout the day. Varying the PBL parameterization, increasing the vertical resolution, and increasing the model spinup time did not significantly improve the results. However, the inclusion of snow cover, increased horizontal resolution, and an improved treatment of horizontal diffusion did have a sizable effect on the forecast quality. The snow cover in the baseline simulation was essential for preventing the diurnal heating from eroding the cold pool, but was only sufficient to produce a nearly isothermal temperature structure within the valley, largely because of an increased reflection of solar radiation. The increase of horizontal resolution to 333 and 111 m resulted in a stronger cold-air pool and its retention throughout the day. In addition to improving the resolution of flow features in steep terrain, resulting in, for example, less drainage out of the valley, the increase in horizontal resolution led to a better forecast because of a reduced magnitude of horizontal diffusion calculated along the terrain-following model surfaces. Calculating horizontal diffusion along the constant height levels had a beneficial impact on the quality of the simulations, producing effects similar to those achieved by increasing the horizontal resolution, but at a fraction of the computational cost.
Rainfall Types in the West African Sudanian Zone during the Summer Monsoon 2002
Authors: Fink A. H. , Vincent D. G. , Ermert V.
Published: August 2006

Enhanced surface and upper-air observations from the field campaign of the Integrated Approach to the Efficient Management of Scarce Water Resources in West Africa (IMPETUS) project are used to partition rainfall amounts over the West African Sudanian zone during the 2002 summer monsoon season into several characteristic types and subtypes of precipitating systems. The most prominent rainfall subtype was fast-moving, long-lived, and extensive cloud clusters that often developed far upstream over the central Nigerian highlands in the afternoon hours and arrived at the Upper Ouémé Valley (UOV) after midnight. These organized convective systems (advective OCSs, subtype Ia) accounted for 50% of the total rain amount in the UOV catchment in Benin. Subtypes Ia and IIa (i.e., locally developing OCSs) were found to pass by or organize when a highly sheared environment with deep and dry midtropospheric layers was present over the UOV. These systems were most frequent outside the peak of the monsoon season. The second major type of organized convection, termed mesoscale convective systems (subtypes Ib, IIb, and IIIb) in the present study, contributed 26% to the annual UOV precipitation. They occurred in a less-sheared and moister tropospheric environment mainly around the height of the rainy season. A third distinct class of rainfall events occurred during an unusual synoptic situation in which a cyclonic vortex to the north of the UOV led to deep westerly flow. During these periods, the African easterly jet was lacking. The so-called vortex-type rainfalls (subtypes IIIa, IIIb, and IIIc) contributed about 9% to the annual rainfall totals.
Enhanced Detectability of Added Value in Limited-Area Model Results Separated into Different Spatial Scales
Authors: Feser Frauke
Published: August 2006

Regional climate models (RCMs) are a widely used tool to describe regional-scale climate variability and change. However, the added value provided by such models is not well explored so far, and claims have been made that RCMs have little utility. Here, it is demonstrated that RCMs are indeed returning significant added value. Employing appropriate spatial filters, the scale-dependent skill of a state-of-the-art RCM (with and without nudging of large scales) is examined by comparing its skill with that of the global reanalyses driving the RCM. This skill is measured by pattern correlation coefficients of the global reanalyses or the RCM simulation and, as a reference, of an operational regional weather analysis. For the spatially smooth variable air pressure the RCM improves this aspect of the simulation for the medium scales if the RCM is driven with large-scale constraints, but not for the large scales. For the regionally more structured quantity near-surface temperature the added value is more obvious. The simulation of medium-scale 2-m temperature anomaly fields amounts to an increase of the mean pattern correlation coefficient up to 30%.
Observational Diagnosis and Model Forecast Evaluation of Unforecasted Incipient Precipitation during the 24–25 January 2000 East Coast Cyclone
Authors: Brennan Michael J. , Lackmann Gary M.
Published: August 2006

Previous research has shown that a lower-tropospheric diabatically generated potential vorticity (PV) maximum associated with an area of incipient precipitation (IP) was critical to the moisture transport north of the PV maximum into the Carolinas and Virginia during the 24–25 January 2000 East Coast cyclone. This feature was almost entirely absent in short-term (e.g., 6–12 h) forecasts from the 0000 UTC 24 January 2000 operational runs of the National Centers for Environmental Prediction (NCEP) North American Mesoscale (NAM, formerly Eta) and Global Forecast System (GFS, formerly AVN) models, even though it occurred over land within and downstream of a region of relatively high data density. Observations and model analyses are used to document the forcing for ascent, moisture, and instability (elevated gravitational and/or symmetric) associated with the IP, and the evolution of the IP formation is documented with radar and satellite imagery with the goal of understanding the fundamental nature of this precipitation feature and the models’ inability to predict it. Results show that the IP formed along a zone of lower-tropospheric frontogenesis in a region of strong synoptic-scale forcing for ascent downstream of an approaching upper trough and jet streak. The atmosphere above the frontal inversion was characterized by a mixture of gravitational conditional instability and conditional symmetric instability over a deep layer, and this instability was likely released when air parcels reached saturation as they ascended the frontal surface. The presence of elevated convection is suggested by numerous surface reports of thunder and the cellular nature of radar echoes in the region. Short-term forecasts from the Eta and AVN models failed to capture the magnitude of the frontogenesis, upper forcing, or elevated instability in the region of IP formation. These findings suggest that errors in the initial condition analyses, particularly in the water vapor field, in conjunction with the inability of model physics schemes to generate the precipitation feature, likely played a role in the operational forecast errors related to inland quantitative precipitation forecasts (QPFs) later in the event. A subsequent study will serve to clarify the role of initial conditions and model physics in the representation of the IP by NWP models.
An Observational Study of Vortex Spacing in Island Wake Vortex Streets
Authors: Young George S. , Zawislak Jonathan
Published: August 2006

Vortex streets are a frequent occurrence in stratocumulus-topped flow downwind of mountainous islands. Theoretical studies dating back to von Kármán, supported by laboratory and numerical studies, have yielded similarity theories for the size and spacing of these vortices behind bluff bodies. Despite dynamical differences between such two-dimensional flows and the three-dimensional flow past isolated islands, satellite case studies suggest these geometric similarities may also hold for the atmospheric case. In this study, two of the resulting dimensionless ratios are measured using satellite imagery. One is the aspect ratio between cross-street and along-street spacing of the vortices. The second is the ratio of the cross-street spacing to the crosswind width of the island. A 30-image sample from the Aqua and Terra Moderate Resolution Imaging Spectroradiometer satellites is analyzed to obtain these ratios. The resulting set of values for the two dimensionless ratios is tested against the values found in bluff body studies. The aspect ratio is tested against the value of 0.28 resulting from von Kármán’s inviscid theory, and the dimensionless width ratio is tested against the value of 1.2 from Tyler’s laboratory study of flow around a bluff body. It is found that atmospheric vortex streets do indeed follow the geometric similarity theories, but with different values for the two ratios than those predicted by von Kármán and Tyler. The aspect ratio is larger than predicted as is the dimensionless width ratio. Both differences are consistent with the turbulent diffusion of vorticity in the wake of the island. The vortex streets more closely follow inviscid theory close to the island, with vortex expansion taking place a few vortex diameters downwind of the island.
Family Structure and Community Context
Authors: Kowaleski-Jones Lori , Dunifon Rachel
Published: August 2006

Using data from the National Longitudinal Survey of Youth merged mother-child file, this article examines the relationship between living in four different family structures on key measures of youth well-being, studied separately by race. The authors also examine whether contextual factors mediate these associations. For Black youth, we find no effects of family structure on youth well-being; however, community context measures are associated with youth outcomes. For White youth, single parenthood and cohabitation are associated with poorer youth outcomes; however, in some cases, these associations are mediated with the inclusion of the community context measures.
When and Why Dropouts Leave High School
Authors: Stearns Elizabeth , Glennie Elizabeth J.
Published: August 2006

Teens may leave school because of academic failure, disciplinary problems, or employment opportunities. In this article, the authors test whether the reasons dropouts leave school differ by grade level and age. We compare dropout rates and reasons across grade levels and ages for all high school students, ethnic groups, and gender groups. Across all students, ninth graders have the highest dropout rate: This pattern persists for Blacks, Latinos, and Native Americans, and for male students. Dropout reasons vary by age, grade, ethnicity, and gender as well. Ninth graders and students aged 16 and younger are more likely than advanced and older students to leave school for disciplinary reasons. Older male students are more likely than younger males to leave school for employment. The significant variation in dropout rates and reasons by grade level and age indicates that multiple dropout processes may influence teens to leave school.
“No Boundaries”? Girls’ Interactive, Online Learning About Femininities
Authors: Kelly Deirdre M. , Pomerantz Shauna , Currie Dawn H.
Published: August 2006

This article explores girls’ learning about issues of femininity that takes place in the presence of others online, connected through chat rooms, instant messaging, and role-playing games. Informed by critical and poststructuralist feminist theorizing of gendered subjectivity, agency, and power, the article draws from qualitative interviews with 16 girls in Vancouver, Canada. Girls reported that online activities allowed them to rehearse different ways of being before trying them out offline, where they might have been reined in for going against perceived expectations for their gender. The article shows that girls enjoyed playing with gender and being gender rebellious. They practiced taking more initiative in heterosexual relationships than is currently authorized in prevailing rules of romance. Without necessarily challenging the underlying gendered power inequalities, some battled back in cyberspace against sexual harassment. In the conclusion, the authors reflect on the implications for girls’ individual and collective empowerment and for transformative pedagogy.
Youth and Adult Perceptions of Their Relationships Within Community-Based Youth Programs
Authors: Jones Kenneth R. , Perkins Daniel F.
Published: August 2006

This study examined perceptions and experiences of youth and adults engaged in various types of community-based youth-adult relationships. Involvement and interaction rating scales were completed by 108 participants involved in community groups from 12 communities in 10 states. The rating scale measured three constructs: youth involvement, adult involvement, and youth-adult interaction. Significant gender differences in participants’ perceptions were found on all three constructs, with females being more positive. Rural participants were found to be significantly more positive than urban participants on the construct of youth involvement. Finally, significant differences were found between all participants within categories of the youth-adult relationship continuum. Participants in youth-led collaborations were significantly more positive toward youth involvement than participants in adult-led collaborations. Moreover, adults in youth-adult partnerships were significantly more positive toward youth involvement and youth-adult interaction than those adults in adult-led collaborations.
The Impact of Marital Conflict and Disruption on Children’s Health
Authors: Houseknecht Sharon K. , Hango Darcy W.
Published: August 2006

This article investigates the effect of inconsistency between parental marital conflict and disruption on children’s health. Inconsistent situations arise when minimal marital conflict precedes disruption or when marital conflict is high but there is no disruption. Using data from the National Longitudinal Survey of Youth, two alternative hypotheses, the stress vulnerable hypothesis and the stress resistant hypothesis, are tested. The latter hypothesis is based on recent evidence in the medical field. The results support the stress resistant hypothesis in that boys’ health is enhanced when there is inconsistency between marital conflict and disruption. There are no significant effects for girls. The widespread notion that marital conflict and disruption have only adverse effects for children is challenged by the findings in this study.
Analysing and evaluating usefulness and usability in electronic information services
Authors: Tsakonas Giannis , Papatheodorou Christos
Published: August 2006

Digital libraries, e-journal platforms, portals, e-prints and other web-based information systems provide services supporting users to perform intense work tasks that require complex interaction activities. The main components of such services are the users, the offered content and the system on which they are performed. This paper presents a model, which analyses the attributes of the electronic information services' components that affect user interaction and correlates them in the usefulness and usability evaluation process. An experimental study traces the relations between usefulness and usability, indicating that these evaluation parameters are interconnected and users do not find discriminating differences between them. The analysis of the content and system attributes suggests that user interaction is affected equally by content and system characteristics. Finally, the study illustrates users' preference for the attributes that constitute a useful system in contrast to those that support usability.
Representing organizational memory for computer-aided utilization
Authors: Ju Teresa L.
Published: August 2006

Organizational memory (OM) is the means by which knowledge from the past is brought to bear on present activities. For effective use of OM, it must be represented in a machine-understandable form, so that man, machine, and OM can work in concert to perform business activities such as problem solving, decision making, workflow management, and organizational learning. To this end, we have developed a knowledge representation scheme that uses a trio of logic, ontology, and computation as knowledge representation constructs, Topic Maps in XML syntax (XTM) and related software tools as the representation technology, and three distinct but closely related ontologies (information, enterprise, and domain ontology) as the operationalized knowledge objects. Based on this knowledge representation scheme, we propose an OM architecture along with a feasible and practical methodology for representing OM to facilitate computer-aided utilization. The methodology has been applied to a laboratory experiment for a provider of knowledge-intensive services dubbed ‘Taiwan's Dun & Bradstreet.’ A field interview indicates that top management endorses the OM architecture and developers confirm the feasibility of the methodology.
A conceptual model integrating trust into planned change activities to enhance technology adoption behavior
Authors: Lippert Susan K. , Davis Miles
Published: August 2006

Trillions of dollars are annually spent on the development and implementation of information technology within the United States and around the world. On average, roughly 50% of such systems are considered failures or fall short of meeting the expectations set forth by management. The lost productivity and high costs associated with these shortcomings necessitate the identification of alternative frameworks for facilitating the successful acceptance and continued internalization of new technologies. Internalization is defined as the effective and continued use of a technology over time. As such, this paper introduces a conceptual model for examining the effect of trust and planned change initiatives on technology adoption behavior. We propose that technology trust and interpersonal trust, when coupled with planned change initiatives, lead to greater technology adoption and internalization. A series of propositions are introduced and examined between trust, planned change, technology adoption, and internalization. Implications and recommendations for future explorations and development are presented.
Electroconvulsive therapy in the treatment of depression in a former ecstasy user
Authors: Freudenmann Roland W. , Schönfeldt-Lecuona Carlos , Spitzer Manfred , Hermle Leopold , Grön Georg
Published: August 2006

Depression in former ecstasy users may not respond to selective serotonin reuptake inhibitors (SSRIs) possibly due to damaged serotonergic synapses following long-term heavy ecstasy use. We report findings in a patient suffering from MDMA-induced depression which was refractory to several antidepressive medications including selective noradrenergic reuptake inhibitor (SNRI) and SSRI. An add-on repeated bilateral electroconvulsive therapy (ECT) was able to achieve a stable remission of affective and cognitive symptoms with a follow-up of more than 1.5 years. Add-on ECT could be a treatment option in former ecstasy users with severe depressive disorders that fail to respond to SSRI and/or SNRI. Clinical trials are needed to evaluate further the usefulness of ECT in this patient group.
The resistance to depressive relapse in menopausal women undergoing tryptophan depletion: preliminary findings
Authors: Epperson C. Neill , Amin Zenab , Naftolin Frederick , Cappiello Angela , Czarkowski Kathryn A. , Stiklus Stephanie , Anderson George M. , Krystal John H.
Published: August 2006

Changes in neuroendocrine function may predispose menopausal women to psychological disturbances characterized by depressed mood, anxiety, irritability, fatigue, insomnia, forgetfulness and decline in Libido. The acute tryptophan depletion paradigm was employed to examine the serotonergic contribution to mood and cognitive function in menopausal women who were within 4 weeks of recovery from an episode of major depression. MenopausaL women whose depression was responsive to treatment with oestradiol, the selective serotonin reuptake inhibitor fluoxetine, or a combination of both treatments underwent assessment of mood and verbal memory on active tryptophan depLetion and sham depLetion test days. Although performance on the deLayed paragraph recall subtest of the Wechsler Memory Scale was impaired by tryptophan depletion, no subjects experienced a relapse of depression or a significant worsening of mood. Results from this pilot study indicate that menopausal women who have recently recovered from a major depressive episode do not experience a worsening of mood with acute tryptophan depletion, despite the existence in this sample of some known risk factors for depressive relapse as a result of these procedures. While preliminary, the results suggest that serotonin may be Less critical to the pathogenesis of depression during the menopause.
Methylphenidate can reduce selectivity in associative learning in an aversive trace conditioning task
Authors: Horsley R.R. , Cassaday Helen J.
Published: August 2006

There are good grounds to expect that methylphenidate (MP) should enhance cognitive function. However, experimental evidence on this point is scant. The present study therefore examined the effects of MP on learning the association between a conditioned stimuLus (CS, in this case, noise) and an unconditioned stimulus (UCS, in this case, footshock) in an aversive variant of a trace conditioning procedure. learning was measured off-the-baseline as conditioned suppression of drinking (both latencies to drink, expressed as suppression ratios, and the amount drunk, expressed as the number of licks, in the presence of the CS). In addition to the measures of discrete cue conditioning, MP effects on contextual conditioning were measured as suppression to apparatus cues and an experimental background stimulus. MP was administered at 1 or 5 mg/kg prior to conditioning sessions. As attention deficit hyperactivity disorder (ADHD) has been characterized as involving a `wide attentional window' (e.g. Shalev and Tsal, 2003), it was predicted that MP, as the treatment of choice for ADHD, should increase selectivity (narrowing the attentional window). This outcome would show as reduced levels of conditioning (compared to control rats) to less informative trace and contextual cues present during conditioning. Contrary to prediction, both 1 and 5 mg/kg MP increased learning about all the available stimuli, including the less informative trace CS and the background stimulus. These findings are consistent with reduced rather than increased selectivity in learning (because of increased rather than decreased conditioning to weak cues) under MP.
Aripiprazole use in individuals with intellectual disability and psychotic or behavioural disorders: a case series
Authors: Shastri Manan , Alla Lakshmiramana , Sabaratnam Manga
Published: August 2006

People with intellectual disabilities may be at greater risk of developing movement disorders as a consequence of their underlying neurological damage, especially when they are treated with typical antipsychotic agents. Aripiprazole is a novel antipsychotic quinolone derivative that has been approved for the treatment of schizophrenia in adults. However, there are few reports on the use of aripiprazole in people with intellectual disabilities. Herein, we report on the use of aripiprazole in five individuals with intellectual disabilities and psychotic illness (four cases) or challenging behaviour (one case). Four of the five patients had an additional diagnosis of schizophrenia and one had autism spectrum disorder and challenging behaviour. Issues related to the usefulness of aripiprazole in the management of schizophrenia and challenging behaviour in people with intellectual disabilities are also discussed. Aripiprazole was well tolerated and effective in each of the cases and appears to be a safe and efficacious alternative in the management of patients with both intellectual disabilities and schizophrenia. It can also be a useful treatment option in the management of challenging behaviour, especially when it is used as a part of a biopsychosocial approach.
Preliminary in vivo evidence of increased N-acetyl-aspartate following eicosapentanoic acid treatment in patients with bipolar disorder
Authors: Frangou Sophia , Lewis MichaeL , Wollard James , Simmons Andrew
Published: August 2006

EthyL-eicosapentanoic acid (ethyL-EPA) may be beneficial in the treatment of bipolar disorder (BD) and may have a neurotrophic/neuroprotective role in patients with neuropsychiatric disorders. To investigate this we examined whether ethyl-EPA treatment of BD patients is associated with increased brain Levels of N-acetylaspartate (NAA), a putative marker of neuronal integrity. Fourteen female BD outpatients with moderate depressive symptoms were administered 2g of ethyL-EPA per day or placebo for 12 weeks in a randomized, double-blind fashion. Quantitative, proton magnetic resonance spectroscopy imaging data were obtained prior to randomization and after 12 weeks of treatment from a single 12 ml volume of interest centred above the body of the corpus callosum. A significant rise in NAA Levels was observed in the ethyl-EPA treatment group compared with the placebo group ( p = 0.027). These results provide the first evidence for a probable neurotrophic role of ethyl-EPA treatment in BD underlining the need for more detailed investigation of its mechanism of action and therapeutic potential.
Philanthropic Strategies in Place-Based, Collaborative Land Conservation: The Packard Foundation's Conserving California Landscape Initiative
Authors: Delfin Francisco , Tang Shui-Yan
Published: August 2006

The Packard Foundation's Conserving California Landscape Initiative (CCLI), a US $175 million 5-year (1998-2003) program intended to conserve 250,000 acres of open space in three regions in California, exemplifies the potential contribution and pitfalls of a private foundation's engagement in contemporary place-based, collaborative conservation. The achievements and limitations of this philanthropic effort are revealed largely through interviews of program officers, grantees, and public officials. Focusing conservation in three regions of the state, employing deliberate grant leveraging, promoting conservation partnerships, approaching conservation on multiple fronts, and building nonprofit capacities, CCLI preserved more than 300,000 acres of land, generated around $700 million in matching funds, raised the profile of conservation in the state and local communities' agenda, and fostered collaboration among diverse publics. However positive, CCLI efforts inevitably raised broader governance issues— transparency and accountability, agenda setting and representation, donor power and grantees' autonomy—related to the enlarged role of private money in public conservation.
Giving Circles: Growing Grassroots Philanthropy
Authors: Eikenberry Angela M.
Published: August 2006

Giving circles entail individuals pooling money and other resources and then deciding together where to give these away. More than this, they educate members about community issues, engage members in voluntary efforts, provide social opportunities, and maintain independence from any particular charity. This article reports on an exploratory study of giving circles in the United States, addressing the questions: What are giving circles and their impacts and how are they unique to the new philanthropy environment? The article concludes by discussing the implications of the giving circle movement for philanthropic and nonprofit professionals.
Devolution and Privatization Proceed and Centralized System Maintained: A Twisted Reality Faced by Japanese Nonprofit Organizations
Authors: Suda Yuko
Published: August 2006

This article examines the intragovernmental and government-private relationships in the area of long-term care for the elderly in Japan, focusing on the impact of the introduction of long-term-care insurance (LTCI) in 2000. The outcome indicated that devolution and privatization were promoted through LTCI although the central government maintained control. This article identified the underlying forces that made the Japanese experience of devolution and privatization unique: the history of the government-private relationship, the dilemma between decentralization and the issue of equity, and the centralized system as the driving force of organizational isomorphism. The challenges and opportunities faced by Japanese nonprofit organizations are discussed based on the findings, as well as the influence of for-profit organizations in the examined area.