Research Papers: Sustainable Cities and Their Built Environments

Systematic Comparison of the Influence of Cool Wall versus Cool Roof Adoption on Urban Climate in the Los Angeles Basin

By Jiachen Zhang, Arash Mohegh, Yun Li, Ronnen Levinson, George Ban-Weiss

Environmental Science & Technology, vol. 52, no. 19

2018

This study for the first time assesses the influence of employing solar reflective “cool” walls on the urban energy budget and summertime climate of the Los Angeles basin. We systematically compare the effects of cool walls to cool roofs, a heat mitigation strategy that has been widely studied and employed, using a consistent modeling framework (the Weather Research and Forecasting model). Adoption of cool walls leads to increases in urban grid cell albedo that peak in the early morning and late afternoon, when the ratio of solar radiation onto vertical walls versus horizontal surfaces is at a maximum. In Los Angeles County, daily average increase in grid cell reflected solar radiation from increasing wall albedo by 0.80 is 9.1 W m-2, 43% of that for increasing roof albedo. Cool walls reduce canyon air temperatures in Los Angeles by 0.43 K (daily average), with the peak reduction (0.64 K) occurring at 09:00 LST and a secondary peak (0.53 K) at 18:00 LST. Per 0.10 wall (roof) albedo increase, cool walls (roofs) can reduce summertime daily average canyon air temperature by 0.05 K (0.06 K). Results reported here can be used to inform policies on urban heat island mitigation or climate change adaptation.


Assessing changes in HIV-related legal and policy environments: Lessons learned from a multi-country evaluation

By Laura Ferguson, Alexandra Nicholson, Ian Henry, Amitrajit Saha, Tilly Sellers, Sofia Gruskin

Public Library of Science One

2018

There is growing recognition in the health community that the legal environment-including laws, policies, and related procedures-impacts vulnerability to HIV and access to HIV-related services both positively and negatively. Assessing changes in the legal environment and how these affect HIV-related outcomes, however, is challenging, and understanding of appropriate methodologies nascent



Climate models can correctly simulate the continuum of global-average temperature variability

By Feng Zhu, Julien Emile-Geay, Nicholas P. McKay, Gregory J. Hakim, Deborah Khider, Toby R. Ault, Eric J. Steig, Sylvia Dee, James W. Kirchner

Proceedings of the National Academy of Sciences of the United States of America

2018

Measures of climate are known to exhibit scaling behavior with large exponents, resulting in larger fluctuations at longer timescales. It has been suggested that climate models underestimate these fluctuations [1-4], casting doubt on their ability to predict the amplitude of climate variability over coming decades and centuries. Using the latest simulations and data syntheses, as well as spectral methods tailored to scaling estimation, we find agreement for spectra derived from observations and models on timescales ranging from interannual to multi-millennial. Our results confirm the existence of a regime transition between orbital and annual peaks [5], occurring around millennial periodicities. That both simple and comprehensive ocean-atmosphere models can reproduce these features suggests that long-range persistence is a consequence of the oceanic integration of both gradual and abrupt climate forcings. The result implies that decadal to millennial variability over the Holocene is partly a consequence of the climate system’s integrated memory of orbital forcing. While climate models imperfectly depict some aspects of spatiotemporal variability, we find that they appear contain the essential physics to correctly simulate the temperature continuum. We hypothesize that the deep ocean plays a key role in integrating forcings, keeping a long memory of past events, and having the ability to strongly influence climate states. We therefore suggest that a critical element of successful simulations at sub-orbital scales are initial conditions of the deep ocean state that are consistent with observations of the recent past. Failing to provide such initial conditions sets the models up for failure.


Does Segregation Matter for Latinos?

By Jorge De la Roca, Ingrid Gould Ellen, Justin Steil

Journal for Housing Economics

2017

We estimate the effects of residential racial segregation on socio-economic outcomes for native-born Latino young adults over the past three decades. Using individual public use micro-data samples from the Census and a novel instrumental variable, we find that higher levels of metropolitan area segregation have negative effects on Latino young adults’ likelihood of being either employed or in school, on the likelihood of working in a professional occupation, and on income. The negative effects of segregation are somewhat larger for Latinos than for African Americans. Controlling for Latino and white exposure to neighborhood poverty, neighbors with college degrees, and industries that saw large increases in high-skill employment explains between one half and two thirds of the association between Latino-white segregation and Latino-white gaps in outcomes.


Diversity, Trust, and Social Learning in Collaborative Governance

By Jangmin Kim, Saba Siddiki, William D. Leach

Public Administration Review

2017

Scholarship on collaborative governance identifies several structural and procedural factors that consistently influence governance outcomes. A promising next step for collaborative governance research is to explore how these factors interact. Focusing on two dimensions of social learning—relational and cognitive—as outcomes of collaboration, this article examines potential interacting effects of participant diversity and trust. The empirical setting entails 10 collaborative partnerships in the United States that provide advice on marine aquaculture policy. The findings indicate that diversity in beliefs among participants is positively related to relational learning, whereas diversity in participants’ affiliations is negatively related to relational learning, and high trust bolsters the positive effects of belief diversity on both relational and cognitive learning. In addition, high trust dampens the negative effects of affiliation diversity on relational learning. A more nuanced understanding of diversity in collaborative governance has practical implications for the design and facilitation of diverse stakeholder groups.


A conceptual model to assess stress-associated health effects of multiple ecosystem services degraded by disaster events in the Gulf of Mexico and elsewhere

By Paul A. Sandifer, Landon C. Knapp, Tracy K. Collier, Amanda L. Jones, Robert-Paul Juster, Christopher R. Kelble, Richard K. Kwok, John V. Miglarese, Lawrence A. Palinkas, Dwayne E. Porter, Geoffrey I. Scott, Lisa M. Smith, William C. Sullivan, and Ariana E. Sutton-Grier

GeoHealth

2017

Few conceptual frameworks attempt to connect disaster-associated environmental injuries to impacts on ecosystem services (the benefits humans derive from nature) and thence to both psychological and physiological human health effects. To our knowledge, this study is one of the first, if not the first, to develop a detailed conceptual model of how degraded ecosystem services affect cumulative stress impacts on the health of individual humans and communities. Our comprehensive Disaster-Pressure State-Ecosystem Services-Response-Health model demonstrates that oil spills, hurricanes, and other disasters can change key ecosystem components resulting in reductions in individual and multiple ecosystem services that support people’s livelihoods, health, and way of life. Further, the model elucidates how damage to ecosystem services produces acute, chronic, and cumulative stress in humans which increases risk of adverse psychological and physiological health outcomes. While developed and initially applied within the context of the Gulf of Mexico, it should work equally well in other geographies and for many disasters that cause impairment of ecosystem services. Use of this new tool will improve planning for responses to future disasters and help society more fully account for the costs and benefits of potential management responses. The model also can be used to help direct investments in improving response capabilities of the public health community, biomedical researchers, and environmental scientists. Finally, the model illustrates why the broad range of potential human health effects of disasters should receive equal attention to that accorded environmental damages in assessing restoration and recovery costs and time frames.


Market Mediators and the Trade-offs of Legitimacy-Seeking Behaviors in a Nascent Category

By Brandon H. Lee, Shon R. Hiatt, Michael Lounsburyc

The Institute for Operations Research and the Management Sciences

2017

Although existing research has demonstrated the importance of attaining legitimacy for new market categories, few scholars have considered the trade-offs associated with such actions. Using the U.S. organic food product category as a context, we explore how one standards-based certification organization—the California Certified Organic Farmers (CCOF)—sought to balance efforts to legitimate a nascent market category with retaining a shared, distinctive identity among its members. Our findings suggest that legitimacy-seeking behaviors undertaken by the standards organization diluted the initial collective identity and founding ethos of its membership. However, by shifting the meaning of “organic” from the producer to the product, CCOF was able to strengthen the categorical boundary, thereby enhancing its legitimacy. By showing how the organization managed the associated trade-offs, this study highlights the double-edged nature of legitimacy and offers important implications for the literatures on legitimacy and new market category formation.


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