Introduction to special section: Active Fault-Related Folding: Structural Evolution, Geomorphologic Expression, Paleoseismology, and Seismic Hazards

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Vietnamese-American Diaspora Philanthropy to Vietnam

Analyzes giving by the Vietnamese diaspora in the United States back to Vietnam. Outlines the 1986-2006 evolution of Vietnamese-American philanthropy from individual to organized efforts; challenges; and recommendations for expanding scale and impact

Performance of 18-Story Steel Momentframe Buildings during a large San Andreas Earthquake - A Southern California-Wide End-to-End Simulation

The mitigation of seismic risk in urban areas in the United States and abroad is of major concern for all governments. Unfortunately no comprehensive studies have attempted to address this issue in a rigorous, quantitative manner. This study tackles this problem head-on for one typical class of tall buildings in southern California. The approach adopted here can be used as a template to study earthquake risk in other seismically sensitive regions of the world, such as Taiwan, Japan, Indonesia, China, South American countries (Chile, Bolivia, etc.), and the west coast of the United States (in particular, Seattle). In 1857 a large earthquake of magnitude 7.9 [1] occurred on the San Andreas fault with rupture initiating at Parkeld in Central California and propagating in a southeasterly direction over a distance of more than 360 km. Such a unilateral rupture produces signicant directivity toward the San Fernando and Los Angeles basins. Indeed, newspaper reports (Los Angeles Star [2, 3]) of sloshing observed in the Los Angeles river point to long-duration (1-2 min) and long-period (2-8 s) shaking, which could have a severe impact on present-day tall buildings, especially in the mid-height range. To assess the risk posing tall steel moment-frame buildings from an 1857-like earthquake on the San Andreas fault, a nite source model of the magnitude 7.9 November 3, 2002 Denali fault earthquake is mapped on to the San Andreas fault with rupture initiating at Parkeld in Central California and propagating a distance of about 290 km in a south-easterly direction. As the rupture proceeds down south from Parkeld and hits the big bend on the San Andreas fault, it sheds off a signicant amount of energy into the San Fernando valley, generating large amplitude ground motion there. A good portion of this energy spills over into the Los Angeles basin with many cities along the coast such as Santa Monica and Seal Beach and more inland areas going east from Seal beach towards Anaheim experiencing long-duration shaking. In addition, the tail-end of the rupture sheds energy from SH/Love waves into the Baldwin Park-La Puente region, which is bounded by a line of mountains that creates a mini-basin, further amplifying the ground motion. The peak velocity is of the order of 1 m.s in the Los Angeles basin, including downtown Los Angeles, and 2 m.s in the San Fernando valley. Signicant displacements occur in the basins but not in the mountains. The peak displacements are in the neighborhood of 1 m in the Los Angeles basin and 2 m in the San Fernando valley. The ground motion simulation is performed using the spectral element method based seismic wave propagation program, SPECFEM3D. To study the effects of the ground motion simulated at 636 sites (spread across southern California, spaced at about 3.5 km each way), computer models of an existing 18-story steel moment-frame building and a redesigned building with the same conguration (redesigned to current standards using the 1997 Uniform Building Code) are analyzed using the nonlinear structural analysis program, FRAME3D. For these analyses, the building Y direction is aligned with the geographical north direction. As expected, the existing building model fares much worse than the redesigned building model. Fracture occurs in at least 25% of the connections in this building when located in the San Fernando valley. About 10% of connections fracture in the building when located in downtown Los Angeles and the mid-Wilshire district (Beverly Hills), while the numbers are about 20% when it is located in Santa Monica, west Los Angeles, Inglewood , Alhambra, Baldwin Park, La Puente, Downey, Norwalk, Brea, Fullerton, Anaheim and Seal Beach. The peak interstory drifts in the middle-third and bottom-third of the existing building are far greater than the top-third pointing to damage being localized to the lower oors. The localization of damage in the lower oors rather than the upper oors could potentially be worse because of the risk of more oors pancaking on top of each other if a single story gives way. Consistent with the extent of fracture observed, the peak drifts in the existing building exceed 0.10 when located in the San Fernando valley, Baldwin Park and neighboring cities, Santa Monica, west Los Angeles and neighboring cities, Norwalk and neighboring cities, and Seal Beach and neighboring cities, which is well into the postulated collapse regime. When located in downtown Los Angeles and the mid-Wilshire district, the building would barely satisfy the collapse prevention criteria set by FEMA [4] with peak drifts of about 0.05. The performance of the newly designed 18-story steel building is signicantly better than the existing building for the entire region. However, the new building still has signicant drifts indicative of serious damage when located in the San Fernando valley or the Baldwin Park area. When located in coastal cities (such as Santa Monica, Seal Beach etc.), the Wilshire-corridor (west Los Angeles, Beverly Hills, etc.), the mid-city region (Downey, Norwalk, etc.) or the booming Orange County cities of Anaheim and Santa Ana, it has peak drifts of about 0.05, once again barely satisfying the FEMA collapse prevention criteria [5]. In downtown Los Angeles it does not undergo much damage in this scenario. Thus, even though this building has been designed according to the latest code, it suffers damage that would necessitate closure for some time following the earthquake in most areas, but this should be expected since this is a large earthquake and building codes are written to limit the loss of life and ensure "collapse prevention" for such large earthquakes, but not necessarily limit damage. Unfortunately, widespread closures such as this could cripple the regional economy in the event of such an earthquake. A second scenario considered in the study involves the same Denali earthquake source mapped to the San Andreas fault but with rupture initiating in the south and propagating to the north (with the largest amount of slip occurring to the north in Central California) instead of the other way around. The results of such a scenario indicate that ground shaking would be far less severe demonstrating the effects of directivity and slip distribution in dictating the level of ground shaking and the associated damage in buildings. The peak drifts in existing and redesigned building models are in the range of 0.02-0.04 indicating that there is no signicant danger of collapse. However, damage would still be signicant enough to warrant building closures and compromise life safety in some instances. The ground motion simulation and the structural damage modeling procedures are validated using data from the January 17, 1994, Northridge earthquake while the band-limited nature of the ground motion simulation (limited to a shortest period of 2 s by the current state of knowledge of the 3-D Earth structure) is shown to have no signicant effect on the response of the two tall buildings considered here with the use of observed records from the 1999 Chi Chi earthquake in Taiwan and the 2001 Tokachi-Oki earthquake in Japan

Methane emissions inventory verification in southern California

Methane (CH4) and carbon monoxide (CO) mixing ratios were measured at an air quality monitoring station near the Mt. Wilson (MW) Observatory in southern California starting in the spring of 2007. Diurnal variation and mixing ratio correlation (R2 = 0.81) were observed. The correlation results observed agree with previous aircraft measurements collected over the greater Los Angeles (LA) metropolitan area. The consistent agreement between CH4 and CO indicates these gases are well-mixed before reaching the sampling site and the emission source contributions of both compounds are reasonably constant. Since CH4 and CO are considered non-reactive on the time scale of dispersion within the LA urban area and their emission sources are likely to be similarly distributed (e.g., associated with human activities) they are subject to similar scales of atmospheric transport and dilution. This behavior allows the relationship of CH4 and CO to be applied for estimation of CH4 emissions using well-documented CO emissions. Applying this relationship a "top-down" CH4 inventory was calculated for LA County based on the measurements observed at MW and compared with the California Air Resources Board (CARB) "bottom-up" CH4 emissions inventory based on the Intergovernmental Panel on Climate Change recommended methodologies. The "top-down" CH4 emissions inventory is approximately one-third greater than CARB's "bottom-up" inventory for LA County. Considering the uncertainties in both methodologies, the different CH4 emissions inventory approaches are in good agreement, although some under and/or uninventoried CH4 sources may exist

Space for Two to Think: Large, High-Resolution Displays for Co-located Collaborative Sensemaking

Large, high-resolution displays carry the potential to enhance single display groupware collaborative sensemaking for intelligence analysis tasks by providing space for common ground to develop, but it is up to the visual analytics tools to utilize this space effectively. In an exploratory study, we compared two tools (Jigsaw and a document viewer), which were adapted to support multiple input devices, to observe how the large display space was used in establishing and maintaining common ground during an intelligence analysis scenario using 50 textual documents. We discuss the spatial strategies employed by the pairs of participants, which were largely dependent on tool type (data-centric or function-centric), as well as how different visual analytics tools used collaboratively on large, high-resolution displays impact common ground in both process and solution. Using these findings, we suggest design considerations to enable future co-located collaborative sensemaking tools to take advantage of the benefits of collaborating on large, high-resolution displays

Disrupted functional brain network organization in patients with obstructive sleep apnea.

IntroductionObstructive sleep apnea (OSA) subjects show impaired autonomic, affective, executive, sensorimotor, and cognitive functions. Brain injury in OSA subjects appears in multiple sites regulating these functions, but the integrity of functional networks within the regulatory sites remains unclear. Our aim was to examine the functional interactions and the complex network organization of these interactions across the whole brain in OSA, using regional functional connectivity (FC) and brain network topological properties.MethodsWe collected resting-state functional magnetic resonance imaging (MRI) data, using a 3.0-Tesla MRI scanner, from 69 newly diagnosed, treatment-naïve, moderate-to-severe OSA (age, 48.3 ± 9.2 years; body mass index, 31 ± 6.2 kg/m(2); apnea-hypopnea index (AHI), 35.6 ± 23.3 events/h) and 82 control subjects (47.6 ± 9.1 years; body mass index, 25.1 ± 3.5 kg/m(2)). Data were analyzed to examine FC in OSA over controls as interregional correlations and brain network topological properties.ResultsObstructive sleep apnea subjects showed significantly altered FC in the cerebellar, frontal, parietal, temporal, occipital, limbic, and basal ganglia regions (FDR, P < 0.05). Entire functional brain networks in OSA subjects showed significantly less efficient integration, and their regional topological properties of functional integration and specialization characteristics also showed declined trends in areas showing altered FC, an outcome which would interfere with brain network organization (P < 0.05; 10,000 permutations). Brain sites with abnormal topological properties in OSA showed significant relationships with AHI scores.ConclusionsOur findings suggest that the dysfunction extends to resting conditions, and the altered FC and impaired network organization may underlie the impaired responses in autonomic, cognitive, and sensorimotor functions. The outcomes likely result from the prominent structural changes in both axons and nuclear structures, which occur in the condition

Green noise or green value? Measuring the price effects of environmental certification in commercial buildings

This paper investigates the price effects of environmental certification on commercial real estate assets. It is argued that there are likely to be three main drivers of price differences between certified and non-certified buildings. First, certified buildings offer a bundle of benefits to occupiers relating to business productivity, image and occupancy costs. Second, due to these occupier benefits, certified buildings can result in higher rents and lower holding costs for investors. Third, certified buildings may require a lower risk premium. Drawing upon the CoStar database of US commercial real estate assets, hedonic regression analysis is used to measure the effect of certification on both rent and price. We first estimate the rental regression for a sample of 110 LEED and 433 Energy Star as well as several thousand benchmark buildings to compare the sample to. The results suggest that, compared to buildings in the same metropolitan region, certified buildings have a rental premium and that the more highly rated that buildings are in terms of their environmental impact, the greater the rental premium. Furthermore, based on a sample of transaction prices for 292 Energy Star and 30 LEED-certified buildings, we find price premia of 10% and 31% respectively compared to non-certified buildings in the same metropolitan are