Home About us Contact
|
Home About us Contact | ||
|
|
||
Detection Efficiency (detection + efficiency)
Selected AbstractsDetection efficiency of multiplexed Passive Integrated Transponder antennas is influenced by environmental conditions and fish swimming behaviourECOLOGY OF FRESHWATER FISH, Issue 4 2009J. C. Aymes Abstract,,, The efficiency of a Passive Integrated Transponder (PIT)-tag detection system was tested during a 23-day experiment using a permanent digital video to record the passage of fish through multiplexed antennas. Coupling video to the PIT system allowed the detection of error sources and the correction of erroneous data. The efficiency of the detection system and its variation were investigated according to fish swimming speed, direction of movement and individual fish behaviour. Influence of time and environmental conditions on detection results were also checked. The PIT tag system was 96.7% efficient in detecting fish. Upstream movements were better detected (99.8%) than downstream movements (93.7%). Moreover, results showed that efficiency rate was not stable over the experiment; it was reduced on stormy days. Several sources of errors were identified such as sub-optimal orientation of the PIT tag relative to the antenna plane, the influence of fish swimming speed, individual fish behaviour and influence of environmental conditions. [source] MapQuant: Open-source software for large-scale protein quantificationPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 6 2006Kyriacos C. Leptos Abstract Whole-cell protein quantification using MS has proven to be a challenging task. Detection efficiency varies significantly from peptide to peptide, molecular identities are not evident a,priori, and peptides are dispersed unevenly throughout the multidimensional data space. To overcome these challenges we developed an open-source software package, MapQuant, to quantify comprehensively organic species detected in large MS datasets. MapQuant treats an LC/MS experiment as an image and utilizes standard image processing techniques to perform noise filtering, watershed segmentation, peak finding, peak fitting, peak clustering, charge-state determination and carbon-content estimation. MapQuant reports abundance values that respond linearly with the amount of sample analyzed on both low- and high-resolution instruments (over a 1000-fold dynamic range). Background noise added to a sample, either as a medium-complexity peptide mixture or as a high-complexity trypsinized proteome, exerts negligible effects on the abundance values reported by MapQuant and with coefficients of variance comparable to other methods. Finally, MapQuant's ability to define accurate mass and retention time features of isotopic clusters on a high-resolution mass spectrometer can increase protein sequence coverage by assigning sequence identities to observed isotopic clusters without corresponding MS/MS data. [source] Snorkelling as a method for assessing spawning stock of Atlantic salmon, Salmo salarFISHERIES MANAGEMENT & ECOLOGY, Issue 3 2007P. ORELL Abstract, Reliability of underwater snorkel counts of adult Atlantic salmon, Salmo salar L., was analysed in the tributaries of the River Teno, close to the spawning period. In small (width 5,20 m) rivers, the replicated total counts of salmon were reasonably precise (CV = 5.4,8.5%), while in the medium-sized river (width 20,40 m) the precision of the counting method was considerably lower (CV = 15.3%). Low precision in a medium sized river was also observed in an experiment using marked live fish where the observation efficiency varied between 36.4% and 70.0%. In a small river, the detection efficiency of artificial fish silhouettes (test salmon) was almost perfect in pools (98%), but decreased in rapids (84%). Separate counts of males, females, grilse and large salmon were usually more variable than total counts, indicating that divers were more capable of locating a fish than properly identifying its sex and sea-age. The behaviour of adult salmon was favourable to conduct snorkel counts, as fish normally stayed still, or after hesitating, moved upstream (>95%of the cases) when encountering a diver. The high observation efficiency (>90%) and precision, favourable behaviour of salmon and congruence between snorkel counts and catch statistics in small rivers suggest that reliable data on Atlantic salmon spawning stock can be collected by snorkeling provided that the environmental conditions are suitable and the divers are experienced. [source] Adaptive joint beamforming and B-MMSE detection for CDMA signal reception under multipath interferenceINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 7 2004Hsiao-Hwa Chen Abstract The combination of antenna array beamforming with multiuser detection can effectively improve the detection efficiency of a wireless system under multipath interference, especially in a fast-fading channel. This paper studies the performance of an adaptive beamformer incorporated with a block-wise minimum mean square error(B-MMSE) detector, which works on a unique signal frame characterized by training sequence preamble and data blocks segmented by zero-bits. Both beam-former weights updating and B-MMSE detection are carried out by either least mean square (LMS) or recursive least square (RLS) algorithm. The comparison of the two adaptive algorithms applied to both beamformer and B-MMSE detector will be made in terms of convergence behaviour and estimation mean square error. Various multipath patterns are considered to test the receiver's responding rapidity to changing multipath interference. The performance of the adaptive B-MMSE detector is also compared with that of non-adaptive version (i.e. through direct matrix inversion). The final performance in error probability simulation reveals that the RLS/B-MMSE scheme outperforms non-adaptive B-MMSE by 1,5 dB, depending on the multipath channel delay profiles of concern. The obtained results also suggest that adaptive beamformer should use RLS algorithm for its fast and robust convergence property; while the B-MMSE filter can choose either LMS or RLS algorithm depending on antenna array size, multipath severity and implementation complexity. Copyright © 2004 John Wiley & Sons, Ltd. [source] An improved method to extract RNA from soil with efficient removal of humic acidsJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2009Y. Wang Abstract Aims:, To remove humic substances from RNA extracted from soil for the study of bacterial gene expression in soil. Methods and Results:, A soil RNA extraction method was improved by optimization of lysis conditions and further purification by a spin column, to efficiently remove humic substances that may hinder enzymatic reactions of extracted RNA. Fluorescence spectrophotometry demonstrated that the improved method removed both humic and fulvic acids efficiently. Using the improved method, the signal of gene expression detected by real-time reverse transcription,polymerase chain reaction (RT-PCR) increased 10-fold compared with that using the previous method. Using the method, we extracted RNA from a sterilized field soil, which was inoculated with Pseudomonas putida KT2440 transformed with a chloroaromatic degrading plasmid, in the presence or absence of 3-chlorobenzoate (3CB). Real-time RT-PCR performed using the extracted RNA as a template confirmed the induction of chloroaromatic degrading genes in 3CB-amended soil. Conclusions:, The modified soil RNA extraction method succeeded in removing the co-extracted humic substances from soil RNA efficiently and improving the detection efficiency of the bacterial gene expression in soil. Significance and Impact of the Study:, This improved method is a useful tool for the extraction of RNA to detect gene expression in soil. [source] Evanescent fields,Direct measurement, modeling, and applicationMICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2007S.T. Huntington Abstract The evanescent field surrounding an exposed planar waveguide in silica is accurately measured using scanning near field optical microscopy (SNOM) and compared to models of the field distribution. Distortions in the field due to edge effects and the proximity of the mode to the surface are all detected. The characterized field is use to quantitatively explore the difference in collection efficiency between contact mode SNOM and intermittent contact mode SNOM. A strong correlation between tip oscillation amplitude and detection efficiency is determined. Microsc. Res. Tech., 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||