![]() ![]() They move both on a solid matrix like soil or agar in a sinusoidal locomotory pattern called “crawling” and in liquid in a different pattern called “swimming”. elegans are free-living soil-dwelling nematodes that navigate in three dimensions. As the cuvette size decreased, so did the oscillation frequency, indicating a change in locomotion when physical constraints are introduced.Ĭ. We find the swimming frequency of unconstrained worms within larger cuvettes to be 2.37 Hz with a variance of 0.02 Hz. Swimming frequencies of nematodes in a droplet of ionic solution on a microscope slide was confirmed to be 2.00 Hz with a variance of 0.05 Hz for the video analysis method and 0.03 Hz for the real time data acquisition using a photodiode this result agrees with previously published estimates using microscope-based analytical techniques. We collected data from diffraction patterns using two methods: video analysis and real time data acquisition using a fast photodiode. We compared these frequencies with those obtained for nematodes swimming within a small droplet of water on a microscope slide, a strategy used by microscope-based locomotion analysis systems. We measured oscillation frequencies for freely swimming nematodes in cuvettes of different sizes to provide different physical constraints on their swimming. This approach consists of tracking the temporal periodicity of diffraction patterns generated by directing laser light onto nematodes in a cuvette. elegans without dependence on microscope-based equipment. We report on a novel analytical approach that provides real-time analysis of freely swimming C. Most studies of microorganismal behavior, in contrast, have been conducted using microscope-based approaches, which limit the movement and behavior to a narrow, nearly two-dimensional focal field. These organisms live and behave in a complex three-dimensional environment. Soil and aquatic multicellular microorganisms play a critical role in the nutrient-cycling and organismal ecology of soil and aquatic ecosystems. elegans Fourier Transform Fourier Analysis Mechanosensation doi: 10.1046/j.1Physics and Astronomy Department, Vassar College, Poughkeepsie, USAĢDepartment of Biology, Vassar College, Poughkeepsie, USAģDepartment of Physics and Pre-Engineering, Delaware State University, Dover, USAĮmail: revised Jaccepted July 8, 2012 Comparison of laser grain size analysis with pipette and sieve analysis: A solution for the underestimation of the clay fraction. Is the laser diffraction method reliable for soil particle size distribution analysis? Soil Sci. Yang Y, Wang L, Wendroth O, Liu B, Cheng C, et al. Critical evaluation of the use of laser diffraction for particle-size distribution analysis. doi: 10.1111/j.Įshel G, Levy GJ, Mingelgrin U, Singer MJ. Revisiting the particle-size distribution of soils: Comparison of different methods and sample pre-treatments. Particle fractionation and particle-size analysis. It was concluded that in typical agricultural soils with < 5% OC and < 60% clay content, both techniques could be used for cheap, fast and reliable estimates of soil texture.ĭay PR, et al. Unlike granulometric measurements of texture such as the LDA, MIRS analysis is not subject to the limitations imposed by the shape and density of particles. In soils with OC removed, the MIRS prediction of clay content improved, indicating interference between over-lapping spectral regions for organic and mineral constituents. The LDA over-estimated clay by ~ 60% (calibration set R 2 = 0.36), indicating that the widely used clay threshold of 5% OC the LDA under-estimated (R 2 = < 0.1) and MIRS over-estimated (R 2 = 0.34) clay content. The MIRS over-estimated clay at low clay content and under-estimated at high clay content (calibration set R 2 = 0.83). The MIRS predictions of clay content were much better than the LDA measurements, but both techniques gave good measurements of sand content. It has used soils with a broad range of organic carbon (OC) contents to investigate whether, as in other techniques, clay-OC aggregation affects the estimation of clay with MIRS. To our knowledge this comparison between LDA and MIRS has not been made previously. Spectroscopic methods for the determination of soil texture are faster and cheaper than the standard methods, but how do the results compare? To address this question, laser diffraction analysis (LDA) and mid-infrared spectroscopy (MIRS) analysis have been compared to conventional sieve-pipette measurements of texture in diverse European and Kenyan soils. ![]()
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