3,306 research outputs found

    Automatic identification of gait events using an instrumented sock

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    Background: textile-based transducers are an emerging technology in which piezo-resistive properties of materials are used to measure an applied strain. By incorporating these sensors into a sock, this technology offers the potential to detect critical events during the stance phase of the gait cycle. This could prove useful in several applications, such as functional electrical stimulation (FES) systems to assist gait. Methods: we investigated the output of a knitted resistive strain sensor during walking and sought to determine the degree of similarity between the sensor output and the ankle angle in the sagittal plane. In addition, we investigated whether it would be possible to predict three key gait events, heel strike, heel lift and toe off, with a relatively straight-forward algorithm. This worked by predicting gait events to occur at fixed time offsets from specific peaks in the sensor signal. Results: our results showed that, for all subjects, the sensor output exhibited the same general characteristics as the ankle joint angle. However, there were large between-subjects differences in the degree of similarity between the two curves. Despite this variability, it was possible to accurately predict gait events using a simple algorithm. This algorithm displayed high levels of trial-to-trial repeatability. Conclusions: this study demonstrates the potential of using textile-based transducers in future devices that provide active gait assistance

    Evidence for Allelopathic Activity of Mikania micrantha H.B.K. on Three Weed Species

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    Laboratory, greenhouse and field studies were conducted to determine the allelopathic potential of Mikania micrantha H.B.K. on the germination and growth of three weed species, A.systasia gangetica (L.) T. Anders., Chrysopogon aciculatus (Ritz.) Trin and Paspalum conjugatum Berg. Germination and fresh weight of all three weeds decreased progressively when exposed to increasing concentrations of aqueous leaf or root extract of Mikania. The phytotoxic effect of root extract on the radicle elongation of the test species was greater than that of leaf extract. The dry weight and rate of emergence of the bioassay species used were affected when Mikania debris (leaf or root) were placed on soil surfaces or incorporated into the soil. P. conjugatum emergence was strongly affected when Mikania (root orleaf) was incorporated into the soil. Soil collectedfrom the field where Mikania had been growing had no effecton the final germination of the three weed species. However, dry weights of A. gangetica and P. conjugatum were significantly reduced when grown in the Mikanilt-infested so

    Estimasi Daya Dukung Lingkungan Pesisir untuk Pengembangan Areal Tambak Berdasarkan Laju Biodegradasi Limbah Tambak di Perairan Pesisir Kabupaten Serang

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    Penelitian ini bertujuan untuk mengestimasi daya dukung lingkungan pesisir Kabupaten Serang untuk pengembangan budidaya tambak berdasarkan laju biodegradasi limbah organik tambak di perairan pesisir. Laju biodegradasi OSS adalah 10.78 ppm/hari untuk perlakuan T0 (kontrol), 14.24 ppm/hari untuk perlakuan T1 (TSS 100 ppm, OSS 58.08 ppm), 12.75 ppm/hari untuk perlakuan T2 (TSS 200 ppm, OSS 145.72 ppm),11.34 ppm/hari untuk perlakuan T3 (TSS 300 ppm, OSS 234.22 ppm), 9.38 ppm/hari untuk perlakuan T4(TSS 400 ppm, OSS 321.86 ppm), dan 8.40 ppm/hari untuk perlakuan T5 (TSS 500 ppm, OSS 410.35 ppm). Dengan musim tanam udang 2 kali dan laju biodegradasi OSS 14.76 ppm/hari, daya dukung maksimum lingkungan pesisir Kabupaten Serang untuk budidaya tambak udang adalah 1 090.55 ha untuk tambak intensif,2 220.82 ha untuk tambak semi intensif, dan 12 595.07 ha untuk tambak tradisional plus. Kombinasi optimum luas tambak yang sesuai dengan potensi lahan tambak adalah 149.16 ha (13.6%)tambak intensif, 975.61 ha (42.6%) tambak semi intensif, dan 5 875.23 ha (43.8%) tambak tradisional plus

    Potency of Vibrio Isolates for Biocontrol of Vibriosis in Tiger Shrimp (Penaeus Monodon) Larvae

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    This study was carried out to obtain Vibrio isolates able to function as biocontrol of vibriosis in shrimp hatchery. Thirty one Vibrio isolates were isolated from tiger shrimp larvae and hatchery environments, i.e. Labuan, Pangandaran, and Lampung, Indonesia. Pathogenic V. harveyi MR5339 was obtained from Maros, South-Sulawesi and was made as a rifampicin resistant mutant (RFR) to screen for those 31 Vibrio isolates in in vitro assays and to allow us to monitor their presence in shrimp larvae and larval rearing water. Almost all Vibrio isolates could inhibit the growth of pathogenic V. harveyi MR5339 RFR. SKT-b isolate from Skeletonema was the most effective to inhibit the growth of V. harveyi MR5339 Rf* and significantly reduced larval mortality in pathogen challenge assays. These prospective biocontrol bacteria, at concentration of 10" CFU/ml, did not show pathogenicity to shrimp larvae. SKT-b was Gram negative, short rod-shape, exhibited yellow colonies on TCBS and swarming on SWC-agar media, motile, utilized glucose and sucrose but not lactose: produced extra-cellular protease and amylase, but did not produce chitmase. Partial sequencing of 16S-rRNA gene SKT-b showed SKT-b similarity to Vibrio alginofyticus

    Spontaneous Interlayer Charge Transfer near the Magnetic Quantum Limit

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    Experiments reveal that a confined electron system with two equally-populated layers at zero magnetic field can spontaneously break this symmetry through an interlayer charge transfer near the magnetic quantum limit. New fractional quantum Hall states at unusual total filling factors such as \nu = 11/15 (= 1/3 + 2/5) stabilize as signatures that the system deforms itself, at substantial electrostatic energy cost, in order to gain crucial correlation energy by "locking in" separate incompressible liquid phases at unequal fillings in the two layers (e.g., layered 1/3 and 2/5 states in the case of \nu = 11/15).Comment: 4 pages, 4 figures (1 color) included in text. Related papers at http://www.ee.princeton.edu/~hari/papers.htm

    Observation of Quantized Hall Drag in a Strongly Correlated Bilayer Electron System

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    The frictional drag between parallel two-dimensional electron systems has been measured in a regime of strong interlayer correlations. When the bilayer system enters the excitonic quantized Hall state at total Landau level filling factor \nu_T=1 the longitudinal component of the drag vanishes but a strong Hall component develops. The Hall drag resistance is observed to be accurately quantized at h/e^2.Comment: 4 pages, 3 figures. Version accepted for publication in Physical Review Letters. Improved discussion of experimental and theoretical issues, added references, correction to figure
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