California State University, Sacramento

About: California State University, Sacramento is a education organization based out in Sacramento, California, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 2445 authors who have published 4478 publications receiving 107786 citations. The organization is also known as: Sacramento State & CSU, Sacramento.

The design structure system: A method for managing the design of complex systems

Abstract: Systems design involves the determination of interdependent variables. Thus the precedence ordering for the tasks of determining these variables involves circuits. Circuits require planning decisions about how to iterate and where to use estimates. Conventional planning techniques, such as critical path, do not deal with these problems. Techniques are shown which acknowledge these circuits in the design of systems. These techniques can be used to develop an effective engineering plan, showing where estimates are to be used, how design iterations and reviews are handled, and how information flows during the design work. This information flow can be used to determine the consequences of a change in any variable on the rest of the variables in the system, and thus which engineers must be informed and which documents must be changed. From this, a critical path schedule can be developed for implementing the change. This method is ideally suited to an automated design office where data, computer input and output, and communications are all handled through the use of computer terminals and data bases. However, these same techniques can also be effectively used in classical engineering environments.

The primary care PTSD screen (PC-PTSD): development and operating characteristics

Abstract: Posttraumatic stress disorder (PTSD) is a frequently unrecognized anxiety disorder in primary care settings. This study reports on the development and operating characteristics of a brief 4-item screen for PTSD in primary care (PC-PTSD). 188 VA primary care patients completed the PC-PTSD, the PTSD Symptom Checklist (PCL) and the Clinician Administered Scale for PTSD (CAPS). The prevalence of PTSD was 24.5%. Signal detection analyses showed that with this base rate, the PC-PTSD had an optimally efficient cutoff score of 3 for both male and female patients. A cutoff score of 2 is recommended when sensitivity rather than efficiency is optimized. The PC-PTSD outperformed the PCL in terms of overall quality, sensitivity, specificity, efficiency, and quality of efficiency. The PC-PTSD appears to be a psychometrically sound screen for PTSD with comparable operating characteristtics to other screens for mental disorders.

Landscape effects on crop pollination services: are there general patterns?

Abstract: Pollination by bees and other animals increases the size, quality, or stability of harvests for 70% of leading global crops. Because native species pollinate many of these crops effectively, conserving habitats for wild pollinators within agricultural landscapes can help maintain pollination services. Using hierarchical Bayesian techniques, we synthesize the results of 23 studies – representing 16 crops on five continents – to estimate the general relationship between pollination services and distance from natural or semi-natural habitats. We find strong exponential declines in both pollinator richness and native visitation rate. Visitation rate declines more steeply, dropping to half of its maximum at 0.6 km from natural habitat, compared to 1.5 km for richness. Evidence of general decline in fruit and seed set – variables that directly affect yields – is less clear. Visitation rate drops more steeply in tropical compared with temperate regions, and slightly more steeply for social compared with solitary bees. Tropical crops pollinated primarily by social bees may therefore be most susceptible to pollination failure from habitat loss. Quantifying these general relationships can help predict consequences of land use change on pollinator communities and crop productivity, and can inform landscape conservation efforts that balance the needs of native species and people.

Gene Flow in Seed Plants

Abstract: Gene dispersal (flow, or migration) within and between plant populations has been of continuous interest to plant breeders and seed producers for many decades. Economic considerations have stimulated studies of gene flow as a function of distance, breeding system, pollinating agent, and planting design in numerous domestic plants. Only during the past two decades have a large body of plant evolutionists become interested in information accruing from these studies, and in the rates of gene flow in wild populations. Their efforts have concentrated primarily on related problems such as adaptations for and mechanics of pollen and seed (or fruit) dispersal, plant-pollinator coevolution, adaptive radiation in pollination and seed dispersal mechanisms, and colonization and the alteration of species boundaries. Early in this century, anecdoctal evidence on the movement of pollen and seed vectors, dispersal of pollen by wind, and the range extensions of weed species led to the casual assumption that gene flow must be extensive, and that it must play a major role in the cohesion of populations and population systems. This view eroded as more information became available and was more critically interpreted (e.g., Grant, 1958, 1971; Ehrlich and Raven, 1969; Stebbins, 1970a; Bradshaw, 1972).