bluuebunny/crossref_metadata_2025 huggingface dataset:
Agile architecture framework for model driven development of C2systems
Authors: Hallberg Niklas , Andersson Richard , Ölvander Christina
Published: June 2009

Command and Control (C2) systems are complex systems composed of personnel, technical equipment, organizational structures, and work procedures. This complexity increases the difficulties involved in developing such systems, which in turn leads to a need for supportive development measures. This paper presents and explores an agile, lightweight, architecture framework for the development of C2systems. The architecture framework prescribes a model‐driven process for structuring the developed models into various levels and views. This facilitates the developers' ability to consider the C2system from a holistic and concurrent perspective. By applying the architecture framework, both the C2system and its context are modeled in order to study how the C2system should be used to support the performance of operational activities, and what support the technical system should provide to the commanders, who are a part of the C2system. The architecture framework provides traceability from the operational level to the technical systems via the C2systems. The architecture framework was iteratively developed and evaluated in three sequential case studies. The outcome shows that the framework supports the initial steps in the development of complex systems, such as C2systems. However, further development and evaluations of the architecture framework are necessary. © 2009 Wiley Periodicals, Inc. Syst Eng
Technology infusion for complex systems: A framework and case study
Authors: Suh Eun Suk , Furst Michael R. , Mihalyov Kenneth J. , Weck Olivier de
Published: June 2009

Manufacturing companies in today's competitive environment constantly need to develop new technologies and infuse them into their line of products to stay ahead of the competition. Most new technologies only deliver value once they are successfully infused into a parent system. However, there has been little research done to develop formal methods to assess the impact of new technology infusion into existing products and systems. In this paper, a systematic framework to quantify and assess the impact of technology infusion early in the product planning cycle is proposed. The proposed methodology quantitatively estimates the impact of technology infusion through the use of a Design Structure Matrix (DSM) and the creation of a Delta DSM (ΔDSM) describing the changes to the original system due to the infused technology. The cost for technology infusion is then estimated from the ΔDSM, and the potential market impact of the technology is calculated based on customer value, expressed through utility curves for system technical performance measures. Finally, the probabilistic ΔNPV of a newly infused technology is obtained using Monte Carlo simulation. The proposed methodology was demonstrated on an actual complex printing system, represented as an 84 element DSM with a density of 3.7%, where a newly developed value‐enhancing technology was infused into the existing product. The result shows that a positive marginal net present value ΔNPV can be expected, despite the new technology causing an invasiveness of 8.5% to the existing design. The methodology can be applied in a rigorous and repeatable manner, opening up possibilities for further implementation of the proposed framework, including analysis of the interactions amongst multiple technologies. © 2009 Wiley Periodicals, Inc. Syst Eng
Lunar architecture and technology analysis driven by lunar science scenarios
Authors: Weisbin Charles R. , Mrozinski Joseph , Lincoln William , Elfes Alberto , Shelton Kacie , Hua Hook , Smith Jeffrey H. , Adumitroaie Virgil , Silberg Robert
Published: June 2009

NASA's Vision for Space Exploration and the missions it comprises pose large‐scale systems‐engineering problems with concomitant large‐budget investment decisions involving multiple disciplines (e.g., science, engineering, information technology), multiple constraints (e.g., time, mass, energy consumption), myriad uncertainties, and a hierarchical structure of problem decomposition with resolution of increasing fidelity. Navigation through this sea of complexity is greatly facilitated by an analytical system that includes optimization and analysis software tools. The interplay between program planning and decision‐support tools is seen here in a case study of a hypothetical mission on the Moon. The architecture of one such tool, HURON, is discussed and its application is illustrated in a comparison of the relative productivity of employing two pressurized or two unpressurized robotic rovers with two pairs of astronauts to conduct a specified group of activities. For the mission scenarios studied, a pair of pressurized rovers is shown to be significantly more productive than a pair of unpressurized rovers when calculating work accomplished divided by marginal operational costs. The HURON decision‐support system presented and successfully applied in this paper deals explicitly with combinatorial explosion of a huge design space in scheduling the activities of agents subject to constraints, deploys a productivity function as a measure of value, and automatically determines a ranked sensitivity list of important inputs. The approach is applicable to a wide class of large‐scale systems‐engineering applications. © 2009 Wiley Periodicals, Inc. Syst Eng
Mapping space‐based systems engineering curriculum to government‐industry vetted competencies for improved organizational performance
Authors: Squires Alice , Larson Wiley , Sauser Brian
Published: June 2009

This paper demonstrates a method that can be used to analyze the degree to which an organization's systems engineering capabilities meet government‐industry defined systems engineering needs. To demonstrate this process, using universities as the case study, we summarize secondary research completed for nine institutions from various countries that offer systems engineering graduate level programs in the space domain. Next, we select a Masters degree program from three universities, one from each country, and map their space‐based systems engineering courses to the 37 systems engineering capabilities within the 10 systems engineering competencies. These capabilities represent the knowledge, skills, and behaviors that systems engineers are expected to possess and perform as a part of their job. We then review a process for a more detailed mapping of the curriculum to one of four levels of proficiency within each capability, using the Stevens Institute of Technology as the example. The result is a systems engineering competency‐based approach that can be used by universities or companies to compare the “as is” state of their systems engineering capabilities development against a government‐industry defined set of needs to identify and address gaps or opportunities in the curriculum, training, or experience of their students and/or employees. © 2009 Wiley Periodicals, Inc. Syst Eng
Identification of proteins associated with the yeast mitochondrial RNA polymerase by tandem affinity purification
Authors: Markov Dmitriy A. , Savkina Maria , Anikin Michael , Del Campo Mark , Ecker Karen , Lambowitz Alan M. , De Gnore Jon P. , McAllister William T.
Published: June 2009

The abundance of mitochondrial (mt) transcripts varies under different conditions, and is thought to depend upon rates of transcription initiation, transcription termination/attenuation and RNA processing/degradation. The requirement to maintain the balance between RNA synthesis and processing may involve coordination between these processes; however, little is known about factors that regulate the activity of mtRNA polymerase (mtRNAP). Recent attempts to identify mtRNAP–protein interactions in yeast by means of a generalized tandem affinity purification (TAP) protocol were not successful, most likely because they involved a C‐terminal mtRNAP–TAP fusion (which is incompatible with mtRNAP function) and because of the use of whole‐cell solubilization protocols that did not preserve the integrity of mt protein complexes. Based upon the structure of T7 RNAP (to which mtRNAPs show high sequence similarity), we identified positions in yeast mtRNAP that allow insertion of a small affinity tag, confirmed the mature N‐terminus, constructed a functional N‐terminal TAP–mtRNAP fusion, pulled down associated proteins, and identified them by LC–MS–MS. Among the proteins found in the pull‐down were a DEAD‐box protein (Mss116p) and an RNA‐binding protein (Pet127p). Previous genetic experiments suggested a role for these proteins in linking transcription and RNA degradation, in that a defect in the mt degradadosome could be suppressed by overexpression of either of these proteins or, independently, by mutations in either mtRNAP or its initiation factor Mtf1p. Further, we found that Mss116p inhibits transcription by mtRNAP in vitro in a steady‐state reaction. Our results support the hypothesis that Mss116p and Pet127p are involved in modulation of mtRNAP activity. Copyright © 2009 John Wiley & Sons, Ltd.
Rights to safe motherhood and newborn health: Ethical issues
Authors: Milliez Jacques
Published: June 2009

Worldwide, one woman dies every minute as a result of being pregnant. This statistic highlights the denial of women's rights to safe motherhood in many parts of the world, particularly in low‐resource countries where 98% all maternal deaths occur. The majority of pregnant women die because they deliver unattended by a properly trained birth professional. According to the 1948 Universal Declaration of Human Rights, every woman has the right to a standard of living adequate for the health and well‐being of herself and her family, including medical care. The principle of moral philosophy supporting women's rights to safe motherhood may be difficult to implement. Philanthropy is diverted by other competing needs, such as HIV prevention and treatment, or provision of urgent food supplies. Equity is denied because women's health is too often set as a low priority. Utilitarianism advocates that safe motherhood is an investment of societal shared interest.
Safe motherhood and newborn health: FIGO initiatives 2006–2010
Authors: Lalonde André B. , McMullen Heather , Lee Amanda C.
Published: June 2009

Through international partnerships, FIGO has been delivering safe motherhood and newborn health (SMNH) projects in a number of low‐income countries. The projects aim to achieve the objectives set out in the ICPD Programme of Action and the Millennium Development Goals 4 and 5, which are related to child survival and maternal mortality. Each project is developed in response to the needs of the intervention region and can be organized around the following themes: provision of maternal and newborn health care services to underserved and hard‐to‐reach areas; improvement and provision of quality basic emergency obstetric care; establishment of functional clinical and perinatal audits; development of new maternal and newborn health care protocols; community education and sensitization to women's rights in sexual and reproductive health; and reducing the risk of unsafe abortion.
Endocytosis and signalling: A meeting with mathematics
Authors: Birtwistle Marc R. , Kholodenko Boris N.
Published: June 2009

Although endocytosis has traditionally been understood as a signal attenuation mechanism, an emerging view considers endocytosis as an integral part of signal propagation and processing. On the short time scale, trafficking of endocytic vesicles contributes to signal propagation from the surface to distant targets, with bi‐directional communication between signalling and trafficking. Mathematical modelling helps combine the mechanistic, molecular knowledge with rigorous analysis of the complex output dynamics of endocytosis in time and space. Simulations reveal novel roles for endocytosis, including the control of cell polarity, enhancing the spatial signal propagation, and controlling the signal magnitudes, kinetics, and synchronization with stimulus dynamics.
THE ASSOCIATION BETWEEN FAMILY STRUCTURE, REPORTS OF ILLNESS AND HEALTH CARE DEMAND FOR CHILDREN: EVIDENCE FROM RURAL BANGLADESH
Authors: RABBANI ATONU , ALEXANDER G. CALEB
Published: June 2009

Access to health care in lesser-developed countries is often quite limited, especially in rural areas. However, less is known about how different factors, such as household structure, parental income and parental education, modify such access to care. This study uses individual-level data from rural Bangladesh during and following a period of major flooding to examine factors associated with reports of illness and demand for doctors in households with children less than 10 years of age. Using information about the number of children who were reported sick and also those who were taken to a doctor, a model was estimated for such reports and decisions to visit a doctor. Overall, 74% of households reported an illness in a child during the study period. The likelihood of reports was significantly greater for boys (36%) than girls (31%). In most analyses, there was no association between parental education and reports of child illness after adjusting for village- and household-level heterogeneity. However, in analyses limited to female children, greater education of the household head was associated with lower odds of such a report (odds ratio [OR] 0.95, 95% confidence interval [CI] 0.91–1.00). Parental education and income were also related to household decisions to seek medical care, though results once again differed based on the sex of the child. There was a particularly strong effect between maternal education level and demand for medical care for boys (OR 1.13; CI 1.01–1.27), though not for girls (OR 0.96; CI 0.84–1.09). Overall, the likelihood of a doctor's visit for a sick child was positively related to household income and at the highest levels of income was a virtual certainty.
Transitions to adulthood and psychological distress in young adults born 12 years apart: constraints on and resources for development
Authors: Sacker A. , Cable N.
Published: June 2009

Background

Later transitions to adult roles and responsibilities have been linked with better psychological well-being yet psychological distress has risen despite young people making the transition to adulthood at older ages over recent years.

Method

We examine the role of structural constraints and adolescent resources in the relationship between the timing of transitions and psychological distress in early adult life in the 1958 National Child Development Study and the 1970 British Cohort Study. Graphical chain models were used to examine the influences on timing of four key transitions and their relationship with psychological distress (Malaise Inventory). The role of structural factors at birth (gender, social class) and adolescent resources (psychosocial problems, exam grades) were modelled.

Results

An earlier transition to adult roles was associated with an increased risk for psychological distress but so was failing to make some key transitions. Structural constraints had negative effects on successful development. Persistent social class and gender inequalities in psychological distress were evident in both cohorts. Social class constraints were mediated by educational resources whereas gender constraints were mediated by psychosocial resources. The influence of structural constraints on the timing of transitions to adult roles was more complex with evidence of positive and negative mediation and moderation effects.

Conclusions

Delaying transition to adulthood promotes psychological health but failure of transition to independent living is associated with psychological distress. Life-course transitions are constrained by social origin and gender and possibly economic environment. Adolescent resources help young adults to make timely transitions to adult roles.
A randomized controlled trial of a cognitive behavioural therapy-based self-management intervention for irritable bowel syndrome in primary care
Authors: Moss-Morris R. , McAlpine L. , Didsbury L. P. , Spence M. J.
Published: June 2009

Background

Recent guidelines for the treatment of irritable bowel syndrome (IBS) emphasize the need for research to facilitate home-based self-management for these patients in primary care. The aim of the current study was to test the efficacy of a manualized cognitive behavioural therapy (CBT)-based self-management programme for IBS in a pilot randomized controlled trial (RCT).

Method

Sixty-four primary-care patients meeting Rome criteria for IBS were randomized into either self-management plus treatment as usual (TAU) (n=31) or a TAU control condition (n=33). The self-management condition included a structured 7-week manualized programme that was self-administered in conjunction with a 1-hour face-to-face therapy session and two 1-hour telephone sessions. The primary outcome measures were the Subject's Global Assessment (SGA) of Relief and the Irritable Bowel Syndrome Severity Scoring System (IBS-SSS) assessed at baseline, end of treatment (2 months), and 3 and 6 months post-treatment.

Results

Analysis was by intention-to-treat. Twenty-three (76.7%) of the self-management group rated themselves as experiencing symptom relief across all three time periods compared to seven (21.2%) of the TAU controls [odds ratio (OR) 12.2, 95% confidence interval (CI) 3.72–40.1]. At 8 months, 25 (83%) of the self-management group showed a clinically significant change on the IBS-SSS compared to 16 (49%) of the control group (OR 5.3, 95% CI 1.64–17.26).

Conclusions

This study provides preliminary evidence that CBT-based self-management in the form of a structured manual and minimal therapist contact is an effective and acceptable form of treatment for primary-care IBS patients.
Age differences in major depression: results from the National Comorbidity Survey Replication (NCS-R)
Authors: Kessler R. C. , Birnbaum H. , Bromet E. , Hwang I. , Sampson N. , Shahly V.
Published: June 2009

Background

Although depression appears to decrease in late life, this could be due to misattribution of depressive symptom to physical disorders that increase in late life.

Method

We studied age differences in major depressive episodes (MDE) in the National Comorbidity Survey Replication, a national survey of the US household population. DSM-IV MDE was defined without organic exclusions or diagnostic hierarchy rules to facilitate analysis of co-morbidity. Physical disorders were assessed with a standard chronic conditions checklist and mental disorders with the WHO Composite International Diagnostic Interview (CIDI) version 3.0.

Results

Lifetime and recent DSM-IV/CIDI MDE were significantly less prevalent among respondents aged ⩾65 years than among younger adults. Recent episode severity, but not duration, was also lower among the elderly. Despite prevalence of mental disorders decreasing with age, co-morbidity of hierarchy-free MDE with these disorders was either highest among the elderly or unrelated to age. Co-morbidity of MDE with physical disorders, in comparison, generally decreased with age despite prevalence of co-morbid physical disorders usually increasing. Somewhat more than half of respondents with 12-month MDE received past-year treatment, but the percentage in treatment was lowest and most concentrated in the general medical sector among the elderly.

Conclusions

Given that physical disorders increase with age independent of depression, their lower associations with MDE in old age argue that causal effects of physical disorders on MDE weaken in old age. This result argues against the suggestion that the low estimated prevalence of MDE among the elderly is due to increased confounding with physical disorders.
Framing tangible interaction frameworks
Authors: Mazalek Ali , van den Hoven Elise
Published: June 2009

Tangible interaction is a growing area of human–computer interaction research that has become popular in recent years. Yet designers and researchers are still trying to comprehend and clarify its nature, characteristics, and implications. One approach has been to create frameworks that help us look back at and categorize past tangible interaction systems, and look forward at the possibilities and opportunities for developing new systems. To date, a number of different frameworks have been proposed that each provide different perspectives on the tangible interaction design space, and which can guide designers of new systems in different ways. In this paper, we map the space of tangible interaction frameworks. We order existing frameworks by their general type, and by the facets of tangible interaction design they address. One of our main conclusions is that most frameworks focus predominantly on the conceptual design of tangible systems, whereas fewer frameworks abstract the knowledge gained from previous systems, and hardly any framework provides concrete steps or tools for building new tangible systems. In addition, the facets most represented in existing frameworks are those that address the interactions with or the physicality of the designed systems. Other facets, such as domain-specific technology and experience, are rare. This focus on design, interaction, and physicality is interesting, as the origins of the field are rooted in engineering methods and have only recently started to incorporate more design-inspired approaches. As such, we expected more frameworks to focus on technologies and to provide concrete building suggestions for new tangible interaction systems.
Tangible interactions in a digital age: Medium and graphic visualization in design journals
Authors: Oehlberg Lora , Lau Kimberly , Agogino Alice
Published: June 2009

Designers are interacting with an increasing number of digital tools in their design process; however, these are usually in addition to the traditional and ubiquitous paper-based design journals. This paper explores the medium of informal design information and its relationships with sketching behavior over three stages of the design process: preliminary investigation and user needs analyses, concept generation and development, and prototyping and testing. Our test bed consists of tangible, digital, and hybrid design journals collected from four semesters of UC Berkeley's graduate level, multidisciplinary course titled “Managing the New Product Development Process: Design Theory and Methods.” We developed protocols for two categories of analysis: one that codes for the media type of each journal and its content, and another one that characterizes the content within the journal. We found a trend toward hybrid digital–tangible journals for the engineering students over the 4-year period. These hybrid journals exhibited a higher degree of detail over advancing design stages, which has been shown to correlate with improved project performance. We also present several case studies of unusual design journals that illustrate the range of designers' interpretations of design journals as a medium. Based on this descriptive research, features for interactive hybrid tangible–digital design journals are recommended.
Analyzing opportunities for using interactive augmented prototyping in design practice
Authors: Verlinden Jouke , Horváth Imre
Published: June 2009

The use of tangible objects is paramount in industrial design. Throughout the design process physical prototypes are used to enable exploration, simulation, communication, and specification of designs. Although much is known about prototyping skills and technologies, the reasons why and how such models are employed in design practice are poorly understood. Advanced techniques and design media such as virtual and augmented prototyping are being introduced without insight as to their benefits. We believe that an augmented prototyping system, that is, employing augmented reality technology to combine physical and digital representations, could positively influence the design process. However, we lack knowledge on why and how it might facilitate design. This paper reports on case studies performed in different domains of industrial design. At each of three Dutch design offices, a project was followed with particular attention to physical prototyping and group activities. The projects encompassed information appliance design, automotive design, and interior design. Although the studies vary in many aspects (product domain, stakeholders, duration), the findings can be applied in conceptualizing advanced prototyping systems to support industrial design. Furthermore, the data reveal that the roles of a prototype in current practice are not necessarily utilitarian; for example, the prototype may serve as a conversation piece or as seducer. Based on so-called “hints,” bottlenecks and best practices concerning concept articulation are linked to usage scenarios for augmented tangible prototyping. The results point to modeling and communication scenarios. Detailed study of the cases indicates that communication activities, especially design reviews, would benefit most from interactive augmented prototyping.
Play-it-by-eye! Collect movies and improvise perspectives with tangible video objects
Authors: Vaucelle Cati , Ishii Hiroshi
Published: June 2009

We present an alternative video-making framework for children with tools that integrate video capture with movie production. We propose different forms of interaction with physical artifacts to capture storytelling. Play interactions as input to video editing systems assuage the interface complexities of film construction in commercial software. We aim to motivate young users in telling their stories, extracting meaning from their experiences by capturing supporting video to accompany their stories, and driving reflection on the outcomes of their movies. We report on our design process over the course of four research projects that span from a graphical user interface to a physical instantiation of video. We interface the digital and physical realms using tangible metaphors for digital data, providing a spontaneous and collaborative approach to video composition. We evaluate our systems during observations with 4- to 14-year-old users and analyze their different approaches to capturing, collecting, editing, and performing visual and sound clips.
The growing Canadian energy gap: more the can than the couch?
Authors: Slater Joyce , Green Christopher G , Sevenhuysen Gustaaf , Edginton Barry , O’Neil John , Heasman Michael
Published: June 2009

Objective

The present study describes the trajectory of the energy gap (energy imbalance) in the Canadian population from 1976 to 2003, its temporal relationship to adult obesity, and estimates the relative contribution of energy availability and expenditure to the energy gap. It also assesses which foods contributed the most to changes in available energy over the study period.

Design

Annual estimates of the energy gap were derived by subtracting population-adjusted per capita daily estimated energy requirements (derived from Dietary Reference Intakes) from per capita daily estimated energy available (obtained from food balance sheets). Food balance sheets were used to assess which foods contributed to changes in energy availability. Adult obesity rates were derived from six national surveys. The relationship to the energy gap was assessed through regression analysis.

Results

Between 1976 and 2003, per capita daily estimated energy availability increased by 18 % (1744 kJ), and increased energy availability was the major driver of the increased energy gap. Salad oils, wheat flour, soft drinks and shortening accounted for the majority of the net increase in energy availability. Adult obesity was significantly correlated with the energy gap over the study period.

Conclusions

The widening energy gap is being driven primarily by increased energy availability. The food commodities driving the widening energy gap are major ingredients in many energy-dense convenience foods, which are being consumed with increasing frequency in Canada. Policies to address population obesity must have a strong nutritional focus with the objective of decreasing energy consumption at the population level.
(Re)Producing American Soldiers in an Age of Empire
Authors: Barker Isabelle V.
Published: June 2009

While there has been little data gathered as to the presence of migrant workers in service occupations on U.S. military bases in Iraq, the data that do exist along with anecdotal evidence gathered by journalists suggest that the division of reproductive labor on military bases reflects an underexplored axis in the global organization of social reproductive labor. Due in part to the privatization of these services, the vast majority of vital support service labor is outsourced to and performed by men migrating from India, Bangladesh, Sri Lanka, the Philippines, Nepal, and Pakistan. This globalized division of reproductive labor is a site of symbolic politics that reinforces the gendered dimensions of the national identity of the American soldier. This division builds off of a long tradition of gendered dynamics framing military service. The displacement of reproductive labor, which remains coded as effeminate, onto poor migrant men serves to reinforce the aggressive masculine version of American soldiering in a way that smoothes over differences among soldiers along the lines of race, class, rural or urban origin, and even gender. Echoing earlier colonizer–colonized relations, this division of labor in turn supports the increasingly imperial posture that the United States has assumed in the world.
Dynamical downscaling of short‐term climate fluctuations: On the benefits of precipitation assimilation
Authors: Nunes Ana M. B. , Roads John O.
Published: June 2009

Regional downscaling has proven useful in adding details to the global solution. However, the parameterized physical processes can systematically deviate the large‐scale features in the regional solution. To demonstrate the precipitation assimilation beneficial impact on the dynamical downscaling, a regional spectral model driven by the National Centers for Environmental Prediction/Department of Energy Atmospheric Model Intercomparison Project II (NCEP/DOE AMIP‐II) Reanalysis was used to downscale the large‐scale features over most of North America. The North American Regional Reanalysis provided the 3‐hourly precipitation rates that the regional model employed to simulate two opposite extreme climate events: the upper Mississippi River Basin 1988 drought and 1993 floods. In addition to these two cases, the 1990 summer anomalous precipitation over the same area was also investigated. Precipitation assimilation positively influences the dynamical downscaling of these extreme climate events. The regional model when assimilating precipitation was particularly successful in reproducing the observed precipitation patterns over the central United States, where the large‐scale circulation affects the precipitation variability. Particularly for the flood year, the intensity and location of the subtropical upper‐level westerly jet and its associated transverse circulations were noticeably improved in the regional simulations, where the heavy precipitation core was found. This also suggests that the cumulus convection scheme, in this case the Relaxed Arakawa‐Schubert parameterization scheme, can cause the large‐scale features to drift during the regional simulation, and precipitation assimilation reduces this departure from the global solution. These changes in the upper‐level winds were also followed by better characterization of the drought of 1988 as well as the 1990 summer heavy precipitation simulation, in comparison to regional control simulations, where precipitation was not assimilated.
Numerical model simulation of the Saharan dust event of 6–11 March 2006 using the Regional Climate Model version 3 (RegCM3)
Authors: Cavazos Carolina , Todd Martin C. , Schepanski Kerstin
Published: June 2009

The Sahara desert is the world's primary source of mineral dust aerosols and is known to be an important but poorly understood component of the climate system. Climate models which incorporate dust modules have the potential to improve our understanding of the climate impacts of dust. In this study, the performance of the Regional Climate Model version 3 (RegCM3) with an active dust scheme is evaluated, using a major dust event of 6–11 March 2006 as a test case. To account for the distribution of preferential dust source regions, soil texture characteristics were modified in dust source regions identified from long‐term SEVIRI satellite data. The dust event was associated with a pronounced cold outbreak of midlatitude air over the northern Sahara which produced anomalously strong northerly winds, which propagated from west to east over the Sahara during the study period. This resulted in dust mobilization from multiple dust sources across the domain. RegCM3 represents the space/time structure of near‐surface meteorology well, although surface winds are underestimated in absolute terms. The experiment in which soils are modified provides a better representation of local dust sources and emission and resulting atmospheric optical thickness (AOT). In this experiment, model simulated dust flux exported from the Sahara to the Sahel and the tropical east Atlantic is estimated as 1.9 Tg d−1. The dust event had a profound impact on the surface solar radiation budget of ∼−140 W m−2 per unit AOT (domain average). The shortwave radiative effect at the top of the atmosphere is ∼−10 W m−2 per unit AOT over the study domain. However, this is strongly dependent on surface albedo. The results also highlight how errors in model simulated circulation lead to errors in the position of the dust plume.
Eddy covariance observations of surface leakage during shallow subsurface CO2 releases
Authors: Lewicki Jennifer L. , Hilley George E. , Fischer Marc L. , Pan Lehua , Oldenburg Curtis M. , Dobeck Laura , Spangler Lee
Published: June 2009

We tested the ability of eddy covariance (EC) to detect, locate, and quantify surface CO2 flux leakage signals within a background ecosystem. For 10 days starting on 9 July 2007, and for 7 days starting on 3 August 2007, 0.1 (Release 1) and 0.3 (Release 2) t CO2 d−1, respectively, were released from a horizontal well ∼100 m in length and ∼2.5 m in depth located in an agricultural field in Bozeman, Montana. An EC station measured net CO2 flux (Fc) from 8 June 2006 to 4 September 2006 (mean and standard deviation = −12.4 and 28.1 g m−2 d−1, respectively) and from 28 May 2007 to 4 September 2007 (mean and standard deviation = −12.0 and 28.1 g m−2 d−1, respectively). The Release 2 leakage signal was visible in the Fc time series, whereas the Release 1 signal was difficult to detect within variability of ecosystem fluxes. To improve detection ability, we calculated residual fluxes (Fcr) by subtracting fluxes corresponding to a model for net ecosystem exchange from Fc. Fcr had reduced variability and lacked the negative bias seen in corresponding Fc distributions. Plotting the upper 90th percentile Fcr versus time enhanced the Release 2 leakage signal. However, values measured during Release 1 fell within the variability assumed to be related to unmodeled natural processes. Fcr measurements and corresponding footprint functions were inverted using a least squares approach to infer the spatial distribution of surface CO2 fluxes during Release 2. When combined with flux source area evaluation, inversion results roughly located the CO2 leak, while resolution was insufficient to quantify leakage rate.
An advanced passive diffusion sampler for the determination of dissolved gas concentrations
Authors: Gardner P. , Solomon D. K.
Published: June 2009

We have designed and tested a passive headspace sampler for the collection of noble gases that allows for the precise calculation of dissolved gas concentrations from measured gas mixing ratios. Gas permeable silicon tubing allows for gas exchange between the headspace in the sampler volume and the dissolved gases in the adjacent water. After reaching equilibrium, the aqueous‐phase concentration is related to the headspace concentration by Henry's law. Gas exchange between the water and headspace can be shut off in situ, preserving the total dissolved gas pressure upon retrieval. Gas samples are then sealed in an all metal container, retaining even highly mobile helium. Dissolved noble gas concentrations measured in these diffusion samplers are in good agreement with traditional copper tube aqueous‐phase samples. These significantly reduce the laboratory labor in extracting the gases from a water sample and provide a simple and robust method for collecting dissolved gas concentrations in a variety of aqueous environments.
Lower crustal earthquakes near the Ethiopian rift induced by magmatic processes
Authors: Keir Derek , Bastow Ian D. , Whaler Kathryn A. , Daly Eve , Cornwell David G. , Hautot Sophie
Published: June 2009

Lower crustal earthquakes are commonly observed in continental rifts at depths where temperatures should be too high for brittle failure to occur. Here we present accurately located earthquakes in central Ethiopia, covering an incipient oceanic plate boundary in the Main Ethiopian Rift. Seismicity is evaluated using the combination of exceptionally well resolved seismic structure of the crust and upper mantle, electromagnetic properties of the crust, rock geochemistry, and geological data. The combined data sets provide evidence that lower crustal earthquakes are focused in mafic lower crust containing pockets of the largest fraction of partial melt. The pattern of seismicity and distribution of crustal melt also correlates closely with presence of partial melt in the upper mantle, suggesting lower crustal earthquakes are induced by ongoing crustal modification through magma emplacement that is driven by partial melting of the mantle. Our results show that magmatic processes control not only the distribution of shallow seismicity and volcanic activity along the axis of the rift valley but also anomalous earthquakes in the lower crust away from these zones of localized strain.
Warming in the Agulhas Current system since the 1980's
Authors: Rouault Mathieu , Penven Pierrick , Pohl Benjamin
Published: June 2009

Since the 1980's, the sea surface temperature of the Agulhas Current system has increased significantly. The warming is due to an augmentation of its transport in response to an increase in wind stress curl in the South Indian Ocean at relevant latitudes. This causes an increase in the fluxes of salt and heat into the Atlantic Ocean and in the transfer of energy from the ocean to the atmosphere. Therefore, the changes we are witnessing in the region could have far reaching consequences on top of the regional impacts on ecosystem and climate. The increase in wind stress curl is consistent with a poleward shift of westerly wind in the Southern Hemisphere reported by others.
Diagnosis of vertical velocities in the upper ocean from high resolution sea surface height
Authors: Klein P. , Isern‐Fontanet J. , Lapeyre G. , Roullet G. , Danioux E. , Chapron B. , Le Gentil S. , Sasaki H.
Published: June 2009

A surface Quasi‐Geostrophy based (eSQG) method to diagnose the vertical velocity field from Sea Surface Height (SSH) is assessed using high resolution simulations. These simulations concern a turbulent eddy field with large Rossby numbers and energetic wind‐driven motions. Results indicate that low‐frequency vertical velocities (and also horizontal motions) can be reconstructed within a range of scales between 20 km and 400 km from the surface down to 500 m. The only information needed is a single high‐resolution SSH snapshot and information on the large‐scale vertical stratification. Inertial motions are naturally filtered because they do not contaminate SSH as we demonstrate. These results are encouraging and further strengthen previous studies using the eSQG method. They indicate that access to high resolution SSH may represent a major advance to retrieve horizontal and vertical fluxes of any tracer in the upper ocean.
Influence of multiple scattering on CloudSat measurements in snow: A model study
Authors: Matrosov Sergey Y. , Battaglia Alessandro
Published: June 2009

The effects of multiple scattering on larger precipitating hydrometers have an influence on measurements of the spaceborne W‐band (94 GHz) CloudSat radar. This study presents initial quantitative estimates of these effects in “dry” snow using radiative transfer calculations for appropriate snowfall models. It is shown that these effects become significant (i.e., greater than approximately 1 dB) when snowfall radar reflectivity factors are greater than about 10–15 dBZ. Reflectivity enhancement due to multiple scattering can reach 4–5 dB in heavier stratiform snowfalls. Multiple scattering effects counteract signal attenuation, so the observed CloudSat reflectivity factors in snowfall could be relatively close to the values that would be observed in the case of single scattering and the absence of attenuation.
Slantwise convection: A candidate for homogenization of deep newly formed dense waters
Authors: van Haren Hans , Millot Claude
Published: June 2009

Observations between 1000 and 2750 m, from a site in the 2800‐m deep part of the western basin of the Mediterranean Sea located in between the Provençal and Algerian subbasins, indicate large variations in water mass properties and stability that are associated with, but not directly caused by, dense‐water formation to the north of the site. These variations are apparently dominated by local convection induced by small‐scale eddies and propagation of inertial waves in stratified and homogeneous layers. Hereby is the horizontal component of Coriolis parameter important, governing slantwise, tilted convective mixing. This mixing creates marginally stable deep waters that are as spicy as near‐surface waters. It is found across some 200–400 m thick layers, which thickness is beyond the typical vertical buoyancy scale relevant for double diffusion. The observed convection is hypothesized to be important for dense‐water formation away from near‐surface sources, modifying the ocean's lower half.
Moving mesoscale plasma precipitation in the cusp
Authors: Taguchi S. , Suzuki S. , Hosokawa K. , Ogawa Y. , Yukimatu A. S. , Sato N. , Collier M. R. , Moore T. E.
Published: June 2009

On 28 March 2001, when the interplanetary magnetic field was strongly duskward, the DMSP F12 spacecraft observed an ion precipitation burst in a latitudinally narrow region near 1200 MLT. A few minutes earlier, the Low Energy Neutral Atom (LENA) imager on the IMAGE spacecraft, whose field of view (FOV) looks into the high‐altitude cusp, detected an enhancement of energetic neutral atom signals, which are produced by the ion injection. The LENA data suggest that the ion injection moved out of its FOV after approximately 4 min. At this time, the ground‐based magnetometers of the IMAGE chain in Svalbard, located westward of LENA's FOV, began to indicate perturbations. These perturbations immediately reached a peak and then ceased; the perturbations lasted 2–3 min. During this interval, there was an enhanced westward flow over Svalbard, as observed by the SuperDARN radars. The EISCAT Svalbard radar detected an enhancement of electron density and temperature that was concurrent with this flow enhancement, suggesting that a plasma precipitation burst accompanied with the flow. These observations, which cover a longitudinally extending region of the cusp, strongly suggest the existence of moving mesoscale plasma precipitation (MMPP). The MMPP travels westward with a longitudinally elongated form. Its leading and trailing edges should be created by the temporal effect of the cusp. The other edges, which lie along the streamline, would originate in a spatially limited region along the open‐closed line. The boundary of the MMPP form is delineated by both the temporal and spatial structures of the cusp.
Cessation of Blood-to-Brain Influx of Interleukin-15 during Development of EAE
Authors: Hsuchou Hung , Pan Weihong , Wu Xiaojun , Kastin Abba J
Published: June 2009

Regulatory changes in cytokine permeation across the blood—brain barrier (BBB) may have crucial roles in central nervous system (CNS) autoimmune disease. Accordingly, we examined the interactions of interleukin (IL)-15 with the cerebral vasculature after induction of experimental autoimmune encephalomyelitis (EAE). In contrast to the influx of 125I-IL15 from blood to the CNS in normal mice and the persistence of IL15 influx in the spinal cord of EAE mice, influx was reduced in the EAE brain. Analyses of disappearance kinetics, FITC (fluorescein isothiocyanate)-albumin space, and delivery of IL15 by in situ perfusion, all indicate that the changes were not caused by BBB disruption but by the rapid availability (high volume of distribution) of IL15 and albumin. Although there was no significant change in the BBB permeation of IL15 in either direction in EAE mice, there was an upregulation of its specific receptor, IL15Rα, and an increased in situ production of IL15 mRNA that showed regional variation in both basal and EAE states. Overall, for IL15, its increased cerebral vascular space in the brain was equally as important as its persistent influx across the blood—spinal cord barrier, indicating that it is fully capable of activating the upregulated IL15Rα in the brain along with the intrinsic CNS source of IL15 in EAE mice.
Decreased Brain Zinc Availability Reduces Hippocampal Neurogenesis in Mice and Rats
Authors: Suh Sang Won , Won Seok Joon , Hamby Aaron M , Yoo Byung Hoon , Fan Yang , Sheline Christian T , Tamano Haruna , Takeda Atsushi , Liu Jialing
Published: June 2009

In the adult brain, neurogenesis occurs in the subgranular zone of the dentate gyrus (DG), where high levels of vesicular zinc are localized in the presynaptic terminals. To determine whether zinc has a role in modulating hippocampal neurogenesis under normal or pathologic conditions, we manipulated the level of vesicular zinc experimentally. To reduce hippocampal vesicular zinc, rats were either fed a zinc-deficient diet or treated with a zinc chelator, clioquinol (CQ). The number of progenitor cells and immature neurons was decreased significantly in the DG after 6 weeks of dietary zinc deprivation. Conversely, the number of progenitor cells and immature neurons was restored after a 2-week reversal to a normal zinc-containing diet. Similarly, a 1-week treatment with the zinc chelator, CQ, reduced the number of progenitor cells. The results of our previous study showed that hypoglycemia increased hippocampal neurogenesis. This study shows that zinc chelation reduced hypoglycemia-induced progenitor cell proliferation and neurogenesis. Finally, the role of vesicular zinc on neurogenesis was further assessed in zinc transporter 3 (ZnT3) gene deleted mice. Zinc transporter 3 knockout (KO) mice had significantly fewer proliferating progenitor cells and immature neurons after hypoglycemia. Our data provide converging evidence in support of the essential role zinc has in modulating hippocampal neurogenesis.