36 research outputs found

    Democracy by Design: The Institutionalization of Community Participation Networks in Los Angeles

    Get PDF
    The paper uses network theory to examine the institutionalization of community governance in Los Angeles. Since the Economic Opportunity Act of 1964 mandated the created of neighborhood level bodies to foster “maximum feasible participation” in program development and implementation, we have witnessed rapid growth in local participative bodies. Their success in developing legitimacy and promoting government accountability, however, has been highly varied. Scholars have attributed this variation to a number of centralized design features (e.g. the degree of political support, the provision of organizational resources, the training for participants) and community characteristics (e.g. social capital, community capacity, SES). Others point to system dynamics and historical processes. For example, Putnam, Feldstein, and Cohen (2003) propose a model of positive feedback in which neighborhood-level activism promotes improved accountability which in turn promotes great activism. Building on the dynamic proposed by Putnam et. al., we develop a network model of institutionalization to explain the process by which neighborhood governance becomes regularized and meaningful. We specifically incorporate the influence of central system features and community characteristics, acknowledging the goal complexity of citizen engagement entities (fostering community capacity, information sharing, greater government accountability, and popular mobilization). We then illustrate the model employing social network data on the political networks that have arisen through the implementation of a system of neighborhood councils in Los Angeles. At the system level, we show how the pattern of network evolution is related to the central design features of the LA system and pre-existing social capital. Then we turn to community level factors and assess the extent to which community contextual factors and organizational dynamics influence network development, with implications for subsequent patterns of involvement and policy influence

    Networks for Representation: Social Capital and the Efficacy of Local Participatory Institutions

    Get PDF
    Efforts to understand the successes and limitations of civil society institutions have inspired a growing literature on social networks, social capital, and the role that social relationships play in developing group norms supporting collective action and in linking groups to network-based resources. The literature has tended to emphasize broad egocentric networks or informal networks of community organizations, largely ignoring the importance of social capital for supporting engagement of the formal participatory institutions that are arising as a way of improving stakeholder input in many cities. The extant research on community-representing organizations has tended to conceptualize social networks in largely metaphorical terms, and has not systematically investigated the manner in which political networks support their operations. This paper argues that differing forms of network resources will support distinct types of activities undertaken by participatory organizations. Our empirical analysis demonstrates that different network resources are employed in different contexts, while suggesting that civil society organizations must overcome basic organizational hurdles related to internal conflict in order to leverage latent network resources

    Surface cloud forcing in the East Pacific stratus deck/cold tongue/ITCZ complex

    Get PDF
    Author Posting. © American Meteorological Society 2006. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 19 (2006): 392–409, doi:10.1175/JCLI3620.1.Data from the Eastern Pacific Investigation of Climate Studies (EPIC) mooring array are used to evaluate the annual cycle of surface cloud forcing in the far eastern Pacific stratus cloud deck/cold tongue/intertropical convergence zone complex. Data include downwelling surface solar and longwave radiation from 10 EPIC-enhanced Tropical Atmosphere Ocean (TAO) moorings from 8°S, 95°W to 12°N, 95°W, and the Woods Hole Improved Meteorology (IMET) mooring in the stratus cloud deck region at 20°S, 85°W. Surface cloud forcing is defined as the observed downwelling radiation at the surface minus the clear-sky value. Solar cloud forcing and longwave cloud forcing are anticorrelated at all latitudes from 12°N to 20°S: clouds tended to reduce the downward solar radiation and to a lesser extent increase the downward longwave radiation at the surface. The relative amount of solar radiation reduction and longwave increase depends upon cloud type and varies with latitude. A statistical relationship between solar and longwave surface cloud forcing is developed for rainy and dry periods and for the full record length in six latitudinal regions: northeast tropical warm pool, ITCZ, frontal zone, cold tongue, southern, and stratus deck regions. The buoy cloud forcing observations and empirical relations are compared with the International Satellite Cloud Climatology Project (ISCCP) radiative flux data (FD) dataset and are used as benchmarks to evaluate surface cloud forcing in the NCEP Reanalysis 2 (NCEP2) and 40-yr ECMWF Re-Analysis (ERA-40). ERA-40 and NCEP2 cloud forcing (both solar and longwave) showed large discrepancies with observations, being too large in the ITCZ and equatorial regions and too weak under the stratus deck at 20°S and north to the equator during the cool season from July to December. In particular the NCEP2 cloud forcing at the equator was nearly identical to the ITCZ region and thus had significantly larger solar cloud forcing and smaller longwave cloud forcing than observed. The net result of the solar and longwave cloud forcing deviations is that there is too little radiative warming in the ITCZ and southward to 8°S during the warm season and too much radiative warming under the stratus deck at 20°S and northward to the equator during the cold season.This research was supported by grants from the NOAA Office of Global Programs, Pan American Climate Studies

    Direct measurement of single-molecule dynamics and reaction kinetics in confinement using time-resolved transmission electron microscopy

    Get PDF
    We report experimental methodologies utilising transmission electron microscopy (TEM) as an imaging tool for reaction kinetics at the single molecule level, in direct space and with spatiotemporal continuity. Using reactions of perchlorocoronene (PCC) in nanotubes of different diameters and at different temperatures, we found a period of molecular movement to precede the intermolecular addition of PCC, with a stronger dependence of the reaction rate on the nanotube diameter, controlling the local environments around molecules, than on the reaction temperature (−175, 23 or 400 °C). Once initiated, polymerisation of PCC follows zero-order reaction kinetics with the observed reaction cross section σobs of 1.13 × 10−9 nm2 (11.3 ± 0.6 barn), determined directly from time-resolved TEM image series acquired with a rate of 100 frames per second. Polymerisation was shown to proceed from a single point, with molecules reacting sequentially, as in a domino effect, due to the strict conformational requirement of the Diels–Alder cycloaddition creating the bottleneck for the reaction. The reaction mechanism was corroborated by correlating structures of reaction intermediates observed in TEM images, with molecular weights measured by using mass spectrometry (MS) when the same reaction was triggered by UV irradiation. The approaches developed in this study bring the imaging of chemical reactions at the single-molecule level closer to traditional concepts of chemistry

    Optically active histidin-2-ylidene stabilised gold nanoparticles

    Get PDF
    Drawing from the natural amino acid chiral pool, L and D histidines were utilized as chiral NHC ligands in the synthesis of NHC-stabilized chiroptical gold nanoparticles. Centrifugal size selection afforded monodisperse gold nanoparticles which display mirrored signals in CD spectroscopy

    Home and Online Management and Evaluation of Blood Pressure (HOME BP) using a digital intervention in poorly controlled hypertension: randomised controlled trial

    Get PDF
    Objective: The HOME BP (Home and Online Management and Evaluation of Blood Pressure) trial aimed to test a digital intervention for hypertension management in primary care by combining self-monitoring of blood pressure with guided self-management. Design: Unmasked randomised controlled trial with automated ascertainment of primary endpoint. Setting: 76 general practices in the United Kingdom. Participants: 622 people with treated but poorly controlled hypertension (>140/90 mm Hg) and access to the internet. Interventions: Participants were randomised by using a minimisation algorithm to self-monitoring of blood pressure with a digital intervention (305 participants) or usual care (routine hypertension care, with appointments and drug changes made at the discretion of the general practitioner; 317 participants). The digital intervention provided feedback of blood pressure results to patients and professionals with optional lifestyle advice and motivational support. Target blood pressure for hypertension, diabetes, and people aged 80 or older followed UK national guidelines. Main outcome measures: The primary outcome was the difference in systolic blood pressure (mean of second and third readings) after one year, adjusted for baseline blood pressure, blood pressure target, age, and practice, with multiple imputation for missing values. Results: After one year, data were available from 552 participants (88.6%) with imputation for the remaining 70 participants (11.4%). Mean blood pressure dropped from 151.7/86.4 to 138.4/80.2 mm Hg in the intervention group and from 151.6/85.3 to 141.8/79.8 mm Hg in the usual care group, giving a mean difference in systolic blood pressure of −3.4 mm Hg (95% confidence interval −6.1 to −0.8 mm Hg) and a mean difference in diastolic blood pressure of −0.5 mm Hg (−1.9 to 0.9 mm Hg). Results were comparable in the complete case analysis and adverse effects were similar between groups. Within trial costs showed an incremental cost effectiveness ratio of £11 ($15, €12; 95% confidence interval £6 to £29) per mm Hg reduction. Conclusions: The HOME BP digital intervention for the management of hypertension by using self-monitored blood pressure led to better control of systolic blood pressure after one year than usual care, with low incremental costs. Implementation in primary care will require integration into clinical workflows and consideration of people who are digitally excluded. Trial registration: ISRCTN13790648

    industries—California. 3. Energy policy—California.

    Full text link
    p. cm. Includes bibliographical references. ISBN: 1-58213-064-
    corecore