Spindle dynamics identification using particle swarm optimization

Optimal parameters to eliminate machining chatter may be identified using analytical stability models which require the dynamics of the tool-holder-spindle-machine assembly. Receptance coupling substructure analysis (RCSA) provides a useful analytical tool to couple measured spindle-machine dynamics with tool-holder models to predict the tool point frequency response function for the assembly. Previous research has demonstrated a procedure to determine all required spindle receptances from a single measurement, where each mode within the measurement bandwidth was modeled as a fixed-free Euler–Bernoulli beam and fit using a manual, iterative procedure. Here, a particle swarm optimization technique is described for fitting the spindle-machine measurement using a fixed-free Euler–Bernoulli beam model for each mode. The performance of the optimization process and RCSA in predicting the tool tip frequency response is evaluated and the results are presented.     

Multi-criteria decision analysis in adaptation decision-making: a flood case study in Finland

Decision-making for the purpose of adaptation to climate change typically involves multiple stakeholders, regions and sectors as well as multiple objectives related to the use of resources and perceived benefits. Standard cost–benefit analysis can be argued to take into account easily monetised effects only. Multi-criteria decision analysis (MCDA) embedded in participatory processes can therefore play an important role in defining the decision context and exploring stakeholders’ preferences. In this paper, a case study on flood protection of the Kokemäki river running through the city of Pori in West Finland was conducted. The study was realised as a MCDA workshop involving the key stakeholders of the region. The analysis produced a robust ranking of the considered flood protection alternatives. According to the stakeholders, the approach was useful as an exploratory way of gaining a deeper and shared understanding of the flood protection. It was shown that MCDA is well suited for decision-making in adaptation to climate change–enhanced extreme events.     

INTEGRATED ASSESSMENT OF USES OF WOODY DRAWS IN AGRICULTURAL LANDSCAPES1

ABSTRACT: This study assesses economic and environmental impacts of uses of woody draws, small natural drainage areas covered by trees and shrubs in agricultural landscapes. Three agricultural uses and four alternative uses are evaluated. A net present value approach is used to compare economic impacts of uses of draws and APEX is used to evaluate the interaction between a woody draw and the contributing upland area and simulate the environmental impacts of uses of draws in the field. The study shows that relative to agricultural uses, alternative uses of draws have significant environmental benefits in terms of reducing surface runoff and sediment and associated pollutants, such as nitrogen, phosphorus and pesticides. Agricultural uses of draws are not always the most profitable option. Certain alternatives, such as curly willow and the mixed buffer, are highly profitable. Agricultural landscapes could be differentially managed to achieve both economic variability and environmental benefits. Government support is necessary to promote alternative uses of woody draws. The support can be in the form of CRP payments or market development of buffer products. Farmers and resource managers can use study results to manage woody draws and evaluate the merits of alternative policies for managing woody draws.     

First-trimester diagnosis of hydrolethalus syndrome in a Chinese family

We report a case resembling hydrolethalus syndrome in a Chinese family. Fetal polydactyly, syndactyly, encephalocele and cardiac malformation were detected on ultrasound examination at 12 weeks' gestation. Termination of pregnancy was performed, and postmortem examination confirmed the findings. This is the first report of a first-trimester prenatal diagnosis of hydrolethalus syndrome in the Chinese population. Copyright © 2004 John Wiley & Sons, Ltd.     

Interactions Between Infectious Foodborne Viruses and Bacterial Biofilms Formed on Different Food Contact Surfaces

Food and Environmental Virology - Bacterial biofilms contribute to contamination, spoilage, persistence, and hygiene failure in the food industry, but relatively little is known about the behavior...     

Consumer-resource body-size relationships in natural food webs

It has been suggested that differences in body size between consumer and resource species may have important implications for interaction strengths, population dynamics, and eventually food web structure, function, and evolution. Still, the general distribution of consumer-'resource body-size ratios in real ecosystems, and whether they vary systematically among habitats or broad taxonomic groups, is poorly understood. Using a unique global database on consumer and resource body sizes, we show that the mean body-size ratios of aquatic herbivorous and detritivorous consumers are several orders of magnitude larger than those of carnivorous predators. Carnivorous predator-prey body-size ratios vary across different habitats and predator and prey types (invertebrates, ectotherm, and endotherm vertebrates). Predator-prey body-size ratios are on average significantly higher (1) in freshwater habitats than in marine or terrestrial habitats, (2) for vertebrate than for invertebrate predators, and (3) for invertebrate than for ectotherm vertebrate prey. If recent studies that relate body-size ratios to interaction strengths are general, our results suggest that mean consumer-resource interaction strengths may vary systematically across different habitat categories and consumer types.     

Perceptions of Species Abundance,Distribution, and Diversity: Lessons from Four Decades of Sampling on a Government-Managed Reserve

/ We examined data relative to species abundance, distribution, anddiversity patterns of reptiles and amphibians to determine how perceptionschange over time and with level of sampling effort. Location data werecompiled on more than one million individual captures or observations of 98species during a 44-year study period on the US Department of Energy's(DOE) Savannah River Site National Environmental Research Park (SRS-NERP) inSouth Carolina. We suggest that perceptions of herpetofaunal speciesdiversity are strongly dependent on level of effort and that land managementdecisions based on short-term data bases for some faunal groups could resultin serious errors in environmental management. We provide evidence thatacquiring information on biodiversity distribution patterns is compatiblewith multiyear spatially extensive research programs and also provide aperspective of what might be achieved if long-term, coordinated researchefforts were instituted nationwide.To conduct biotic surveys on government-managed lands, we recommend revisionsin the methods used by government agencies to acquire and report biodiversitydata. We suggest that government and industry employees engaged inbiodiversity survey efforts develop proficiency in field identification forone or more major taxonomic groups and be encouraged to measure the status ofpopulations quantitatively with consistent and reliable methodologies. Wealso suggest that widespread academic cooperation in the dissemination ofinformation on regional patterns of biodiversity could result byestablishment of a peer-reviewed, scientifically rigorous journal concernedwith status and trends of the biota of the United States. KEY WORDS: Abundance; Amphibian; Biodiversity; Distribution; Landmanagement; Reptile