Time filter

Source Type

Sacramento, CA, United States

Parada L.M.,CA Capital | Liang X.,University of Pittsburgh
Advances in Water Resources

In this paper, we present a novel paradigm for inference of streamflow for ungauged basins. Our innovative procedure fuses concepts from both kernel methods and data assimilation. Based on the modularity and flexibility of kernel techniques and the strengths of the variational Bayesian Kalman filter and smoother, we can infer streamflow for ungauged basins whose hydrological and system properties and/or behavior are non-linear and non-Gaussian. We apply the proposed approach to two watersheds, one in California and one in West Virginia. The inferred streamflow signals for the two watersheds appear promising. These preliminary and encouraging validations demonstrate that our new paradigm is capable of providing accurate conditional estimates of streamflow for ungauged basins with unknown and non-linear dynamics. © 2010 Elsevier Ltd. Source

Gopal A.,University of Maryland University College | Gosain S.,CA Capital
Information Systems Research

Past research has studied how the selection and use of control portfolios in software projects is based on environmental and task characteristics. However, little research has examined the consequences of control mode choices on project performance. This paper reports on a study that addresses this issue in the context of outsourced software projects. In addition, we propose that boundary-spanning activities between the vendor and the client enable knowledge sharing across organizational and knowledge domain boundaries. This is expected to lead to facilitation of control through specific incentives and performance norms that are suited to client needs as well as the vendor context. Therefore, we argue that boundary spanning between the vendor and client moderates the relationship between formal controls instituted by the vendor on the development team and project performance. We also hypothesize the effect of collaboration as a clan control on project performance. We examine project performance in terms of software quality and project efficiency. The research model is empirically tested in the Indian software industry setting on a sample of 96 projects. The results suggest that formal and informal control modes have a significant impact on software project outcomes, but need to be finely tuned and directed toward appropriate objectives. In addition, boundary-spanning activities significantly improve the effectiveness of formal controls. Finally, we find that collaborative culture has provided mixed benefits by enhancing quality but reducing efficiency. © 2010 INFORMS. Source

Schatz M.,Kaiser Permanente | Hsu J.-W.Y.,Kaiser Permanente | Zeiger R.S.,Kaiser Permanente | Chen W.,Kaiser Permanente | And 3 more authors.
Journal of Allergy and Clinical Immunology

Background Asthma phenotyping can facilitate understanding of disease pathogenesis and potential targeted therapies. Objective To further characterize the distinguishing features of phenotypic groups in difficult-to-treat asthma. Methods Children ages 6-11 years (n = 518) and adolescents and adults ages ≥12 years (n = 3612) with severe or difficult-to-treat asthma from The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study were evaluated in this post hoc cluster analysis. Analyzed variables included sex, race, atopy, age of asthma onset, smoking (adolescents and adults), passive smoke exposure (children), obesity, and aspirin sensitivity. Cluster analysis used the hierarchical clustering algorithm with the Ward minimum variance method. The results were compared among clusters by χ2 analysis; variables with significant (P <.05) differences among clusters were considered as distinguishing feature candidates. Associations among clusters and asthma-related health outcomes were assessed in multivariable analyses by adjusting for socioeconomic status, environmental exposures, and intensity of therapy. Results Five clusters were identified in each age stratum. Sex, atopic status, and nonwhite race were distinguishing variables in both strata; passive smoke exposure was distinguishing in children and aspirin sensitivity in adolescents and adults. Clusters were not related to outcomes in children, but 2 adult and adolescent clusters distinguished by nonwhite race and aspirin sensitivity manifested poorer quality of life (P <.0001), and the aspirin-sensitive cluster experienced more frequent asthma exacerbations (P <.0001). Conclusion Distinct phenotypes appear to exist in patients with severe or difficult-to-treat asthma, which is related to outcomes in adolescents and adults but not in children. The study of the therapeutic implications of these phenotypes is warranted. © 2014 American Academy of Allergy, Asthma & Immunology. Source

Humphreys M.K.,University of California at Davis | Panacek E.,University of California at Davis | Green W.,University of California at Berkeley | Albers E.,CA Capital
Journal of Forensic Sciences

Protocols for determining postmortem submersion interval (PMSI) have long been problematic for forensic investigators due to the wide variety of factors affecting the rate of decomposition of submerged carrion. Likewise, it has been equally problematic for researchers to develop standardized experimental protocols to monitor underwater decomposition without artificially affecting the decomposition rate. This study compares two experimental protocols: (i) underwater in situ evaluation with photographic documentation utilizing the Heaton et al. total aquatic decomposition (TAD) score and (ii) weighing the carrion before and after submersion. Complete forensic necropsies were performed as a control. Perinatal piglets were used as human analogs. The results of this study indicate that in order to objectively measure decomposition over time, the human analog should be examined at depth using the TAD scoring system rather than utilizing a carrion weight evaluation. The acquired TAD score can be used to calculate an approximate PMSI. © 2012 American Academy of Forensic Sciences. Source

Karp D.S.,Stanford University | Mendenhall C.D.,Stanford University | Sandi R.F.,Copal de Agua Buena | Chaumont N.,CA Capital | And 3 more authors.
Ecology Letters

Efforts to maximise crop yields are fuelling agricultural intensification, exacerbating the biodiversity crisis. Low-intensity agricultural practices, however, may not sacrifice yields if they support biodiversity-driven ecosystem services. We quantified the value native predators provide to farmers by consuming coffee's most damaging insect pest, the coffee berry borer beetle (Hypothenemus hampei). Our experiments in Costa Rica showed birds reduced infestation by ~ 50%, bats played a marginal role, and farmland forest cover increased pest removal. We identified borer-consuming bird species by assaying faeces for borer DNA and found higher borer-predator abundances on more forested plantations. Our coarse estimate is that forest patches doubled pest control over 230 km2 by providing habitat for ~ 55 000 borer-consuming birds. These pest-control services prevented US$75-US$310 ha-year-1 in damage, a benefit per plantation on par with the average annual income of a Costa Rican citizen. Retaining forest and accounting for pest control demonstrates a win-win for biodiversity and coffee farmers. © 2013 John Wiley & Sons Ltd/CNRS. Source

Discover hidden collaborations