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11.
Tree health is a critical parameter for evaluating urban ecosystem health and sustainability. Traditionally, this parameter
has been derived from field surveys. We used multispectral remote sensing data and GIS techniques to determine tree health
at the University of California, Davis. The study area (363 ha) contained 8,962 trees of 215 species. Tree health conditions
were mapped for each physiognomic type at two scales: pixel and whole tree. At the pixel scale, each tree pixel within the
tree crown was classified as either healthy or unhealthy based on vegetation index values. At the whole tree scale, raster
based statistical analysis was used to calculate tree health index which is the ratio of healthy pixels to entire tree pixels
within the tree crown. The tree was classified as healthy if the index was greater than 70%. Accuracy was checked against
a random sample of 1,186 trees. At the whole tree level, 86% of campus trees were classified as healthy with 88% mapping accuracy.
At the pixel level, 86% of the campus tree cover was classified as healthy. This tree health evaluation approach allows managers
to identify the location of unhealthy trees for further diagnosis and treatment. It can be used to track the spread of disease
and monitor seasonal or annual changes in tree health. Also, it provides tree health information that is fundamental to modeling
and analysis of the environmental, social, and economic services produced by urban forests. 相似文献
12.
Perry C. Oddo Ben S. Lee Gregory G. Garner Vivek Srikrishnan Patrick M. Reed Chris E. Forest Klaus Keller 《Risk analysis》2020,40(1):153-168
Sea levels are rising in many areas around the world, posing risks to coastal communities and infrastructures. Strategies for managing these flood risks present decision challenges that require a combination of geophysical, economic, and infrastructure models. Previous studies have broken important new ground on the considerable tensions between the costs of upgrading infrastructure and the damages that could result from extreme flood events. However, many risk-based adaptation strategies remain silent on certain potentially important uncertainties, as well as the tradeoffs between competing objectives. Here, we implement and improve on a classic decision-analytical model (Van Dantzig 1956) to: (i) capture tradeoffs across conflicting stakeholder objectives, (ii) demonstrate the consequences of structural uncertainties in the sea-level rise and storm surge models, and (iii) identify the parametric uncertainties that most strongly influence each objective using global sensitivity analysis. We find that the flood adaptation model produces potentially myopic solutions when formulated using traditional mean-centric decision theory. Moving from a single-objective problem formulation to one with multiobjective tradeoffs dramatically expands the decision space, and highlights the need for compromise solutions to address stakeholder preferences. We find deep structural uncertainties that have large effects on the model outcome, with the storm surge parameters accounting for the greatest impacts. Global sensitivity analysis effectively identifies important parameter interactions that local methods overlook, and that could have critical implications for flood adaptation strategies. 相似文献
13.
This article extends the previous research of consecutive attacks strategy by assuming that an attacker observes the outcome of each attack imperfectly. With given probabilities it may wrongly identify a destroyed target as undestroyed, and wrongly identify an undestroyed target as destroyed. The outcome of each attack is determined by a contest success function that depends on the amount of resources allocated by the defender and the attacker to each attack. The article suggests a probabilistic model of the multiple attacks and analyzes how the target destruction probability and the attacker's relative resource expenditure are impacted by the two probabilities of incorrect observation, the attacker's and defender's resource ratio, the contest intensity, the number of attacks, and the resource distribution across attacks. We analyze how the attacker chooses the number of attacks, the attack stopping rule, and the optimal resource distribution across attacks to maximize its utility. 相似文献
14.
15.
Heidi Tavakoli Gregory Smith 《Development policy review : the journal of the Overseas Development Institute》2013,31(1):59-74
This article analyses evidence for each of the expected benefits of budget support in turn, and finds the biggest improvements in the pro‐poor nature of public expenditure and public financial management. More modest improvements are noted in the predictability of aid and the burden of transaction costs, while less is known about the real effects on domestic accountability. Underlying them all is an assessment that programmes are incapable of ‘buying’ reforms. Drawing on the analysis, seven areas are highlighted where budget support design can be strengthened vis‐à‐vis its original rationale. 相似文献
16.
Virgil L. Gregory Jr. 《Journal of social service research》2013,39(5):460-469
ABSTRACT The purposes of this review article are to orient clinical social workers to cognitive-behavioral theory, intervention, and research on bipolar disorder (BD); identify pros and cons of applying cognitive-behavioral therapy (CBT) to social work clients with BD; and identify specific implications for clinical social work practice. Of the 545 articles that were obtained via the systematic review, 18 studies were identified as being potentially eligible for inclusion, and 9 of those studies ultimately satisfied the inclusion criteria. The results of each study were summarized via identifying statistically significant (p< .05) differences that existed between experimental cohorts who received CBT (plus pharmacotherapy) and control cohorts who received treatment as usual. Outcomes showed CBT cohorts as having significant improvement over their respective control groups. The review's implications for clinical social workers and the need for future research are discussed. 相似文献
17.
Gregory Ponthiere 《Social indicators research》2007,84(2):203-230
Whereas period life expectancy constitutes an intuitive indicator of the survival conditions prevailing at a particular period,
this paper argues that, given the existence of welfare interdependencies, that widespread indicator is nonetheless an incomplete
measure of the longevity achievements relevant for human well-being. The central importance of coexistence for human-beings
implies that usual life expectancy measures should be complemented by joint life expectancy indicators, which measure the
average coexistence time under particular survival conditions. After a study of the theoretical foundations of ‘single’ and
‘joint’ life expectancy indicators, it is shown that joint life expectancy measures tend to enrich significantly the comparison
of longevity achievements across countries and periods. Moreover, the introduction of joint life expectancy indicators—as
a complement to conventional life expectancy measures—into multi-variable indexes such as the United Nations’ HDI is also
shown to affect international rankings of standards of living to a non negligible extent.
相似文献
Gregory PonthiereEmail: |
18.
Putman Breanna J. Gasca Maria Blumstein Daniel T. Pauly Gregory B. 《Urban Ecosystems》2019,22(6):1071-1081
Urban Ecosystems - Urbanization-induced habitat loss and alteration causes significant challenges for the survival of many species. Identifying how species respond to urbanization can yield... 相似文献
19.
Gregory B. UptonJr. 《Journal of Labor Research》2016,37(2):235-261
This paper analyzes the effect of a statewide merit-based scholarship program on educational outcomes in Arizona. It tests whether Arizona’s Instrument to Measure Standards (AIMS) scholarship has an effect on a comprehensive set of educational outcomes such as the number of applicants, student admissions, first-year first-time enrollment, ACT scores of entering freshman, retention rates, as well as on the level of tuition and fees at the three schools targeted by the program; Arizona State University, University of Arizona and Northern Arizona University. Both difference-in-differences estimation as well as synthetic control methods shows that AIMS has an economically and statistically significant effect enrollment. Enrollment effects are greatest among African American and Hispanic students and are significant for both men and women. While point estimates suggest that AIMS also lead to increases in tuition and fees, these results are not robust to placebo tests. 相似文献
20.
Nicolas Souchon Andrew G. Livingstone Brigitte Bardin Olivier Rascle Geneviève Cabagno Gregory R. Maio 《Social Influence》2016,11(4):246-258
The influence of competition level on referees’ decision-making was investigated. Referees’ decisions in 90 handball games (30 games X 3 competition levels) were observed in different situations related to the advantage rule, and 100 referees from two different levels of expertise were subsequently asked to offer explanations for the competition-level effects from the first part of the study. Results revealed that at the highest level of competition referees intervened less frequently with sporting sanctions, but more frequently with disciplinary sanctions. These effects were apparent mainly in immediate intervention situations and unsuccessful advantage situations, but not in successful situations. Referees explained these effects of competition level in terms of a player competence stereotype, in addition to referees’ different expertise across competition level. The implications of the findings for understanding how status-related stereotypes impact on intervention behavior are discussed. 相似文献