نتایج جستجو برای: biological methods
تعداد نتایج: 2252205 فیلتر نتایج به سال:
developing reliable and eco-friendly processes for the synthesis of metallic nanoparticles is an essential step in the field of application of nanotechnology .using natural factories such as biological systems is a way of developing such processes. nowadays, the synthesis of silver nanoparticles is very common due to its numerous applications in different fields. the synthesis of these nanopart...
abstract ion selective electrodes (ises) are electrochemical sensors that respond selectivity to the activity of ionic species. an ion-selective electrode is an electrochemical device that uses a thin selective membrane or film as the recognition element, and is an electrochemical half-cell equivalent to other half-cells of the zeroth (inert metal in a redox electrolyte). in common methods o...
The present study examines the sex-specific patterns of mortality by birth order in four stages of the life-course, using Poisson and logistic regression analysis. The main question posed is whether there is any continuing social effect of birth order when (a) biological factors at birth, (b) other social factors at birth and (c) socio-economic circumstances in adulthood are adjusted for. The a...
An interesting toxicological bioassay (fertilization inhibition in sea urchin) uses as assessment criterion a variable (fertilization ratio) whose variation with time creates two types of difficulties. First, it fails to distinguish between the toxic effect and the spontaneous decline in the sperm activity, causing some inconsistencies. Second, the sensitivity of the fertilization ratio to many...
Evolution has conserved "economic" systems that perform many functions, faster or better, with less. For example, three to five leukocyte types protect from thousands of pathogens. To achieve so much with so little, biological systems combine their limited elements, creating complex structures. Yet, the prevalent research paradigm is reductionist. Focusing on infectious diseases, reductionist a...
Much progress has been made in developing techniques for characterizing population dynamics of nematodes. Nevertheless, most assay procedures have numerous inherent limitations (1,13). The efficiency of given methods may be dependent on soil type, moisture, and other environmental and biological factors (1,13). Certain extraction methods (e.g., Baermann funnel) depend on nematode motility. In a...
Robustness is an important requirement for almost all kinds of products. In this article we show how evolutionary algorithms can be applied for robust design based on the approach of Taguchi. As an example we consider the design of multilayer optical coatings most frequently used for optical lters.
BACKGROUND A variety of different approaches to measuring contraceptive use have been used or proposed, either to assess current use or adherence over time, using subjective or objective measures. This paper reports an overview of approaches to measuring adherence to the oral contraceptive, intra-uterine device, sub-dermal implant, and injectable and describes how we assessed contraception use ...
in reality, most structures involved in geotechnical engineering are three dimensional in nature, and although in many, plane strain or axisymmetric approximations are reasonable, there are some, for which 3-d treatment is required. the quantity of data, and the size of the various vectors and matrices involved in such analysis, increase dramatically. this has sever implications for computer r...
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