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1
Zhao, Jiayi, Yongliang Wang, Guisheng Liao, Xiaoning Liu, Kun Li, Chunyu Yu, Yang Zhai, Hang Xing, and Xuepan Zhang. "Intelligent Detection and Segmentation of Space-Borne SAR Radio Frequency Interference." Remote Sensing 15, no. 23 (November 22, 2023): 5462. http://dx.doi.org/10.3390/rs15235462.
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Space-borne synthetic aperture radar (SAR), as an all-weather observation sensor, is an important means in modern information electronic warfare. Since SAR is a broadband active radar system, radio frequency interference (RFI) in the same frequency band will affect the normal observation of the SAR system. Untangling the above problem, this research explores a quick and accurate method for detecting and segmenting RFI-contaminated images. The purpose of the current method is to quickly detect the existence of RFI and to locate it in massive SAR data. Based on deep learning, the method shown in this paper realizes the existence of RFI by determining the presence or absence of interference in the image domain and then performs pixel-level image segmentation on Sentinel-1 RFI-affected quick-look images to locate RFI. Considering the need to quickly detect RFI in massive SAR data, an improved network based on MobileNet is proposed, which replaces some inverted residual blocks in the network with ghost blocks, reducing the number of network parameters and the inference time to 6.1 ms per image. Further, this paper also proposes an improved network called the Smart Interference Segmentation Network (SISNet), which is based on U2Net and replaces the convolution of the VGG blocks in U2Net with a residual convolution and introduces attention mechanisms and a modified RFB module to improve the segmentation mIoU to 87.46% on average. Experiment results and statistical analysis based on the MID dataset and PAIS dataset show that the proposed methods can achieve quicker detection than other CNNs while ensuring a certain accuracy and can significantly improve segmentation performance under the same conditions compared to the original U2Net and other semantic segmentation networks.
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Zhang, Hengrui, Lin Min, Jing Lu, Jike Chang, Zhengwei Guo, and Ning Li. "An Improved RFI Mitigation Approach for SAR Based on Low-Rank Sparse Decomposition: From the Perspective of Useful Signal Protection." Remote Sensing 14, no. 14 (July 7, 2022): 3278. http://dx.doi.org/10.3390/rs14143278.
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As an open system, synthetic aperture radar (SAR) inevitably receives radio frequency interference (RFI) generated by electromagnetic equipment in the same band. The existence of RFI seriously affects SAR signal processing and image interpretation. In recent years, many algorithms and models related to RFI mitigation have been proposed. However, most of that focus on effectively mitigating the RFI is insufficient to protect the useful signals. This article proposes a mitigation method of RFI with a signal-protected capability. (1) The kurtosis coefficient is used to detect RFI pulse-by-pulse, and the echoes containing RFI are stored in matrix form. (2) The preliminary extraction of RFI is complete by low-rank sparse decomposition of the echo matrix containing RFI. (3) For the secondary separation of RFI, the accurate position of RFI in the preliminary extraction results is located by the fuzzy C-means clustering; then, we separate the RFI and the remaining useful signals again and reconstruct the useful signals to complete the mitigation work. The proposed method can further protect useful signals while effectively removing interference through the secondary separation of RFI. Experimental results based on simulated and measured data verify the performance and potential of the proposed method.
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Prudhomme, Christel, Simon Parry, Jamie Hannaford, Douglas B. Clark, Stefan Hagemann, and Frank Voss. "How Well Do Large-Scale Models Reproduce Regional Hydrological Extremes in Europe?" Journal of Hydrometeorology 12, no. 6 (December 1, 2011): 1181–204. http://dx.doi.org/10.1175/2011jhm1387.1.
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Abstract This paper presents a new methodology for assessing the ability of gridded hydrological models to reproduce large-scale hydrological high and low flow events (as a proxy for hydrological extremes) as described by catalogues of historical droughts [using the regional deficiency index (RDI)] and high flows [regional flood index (RFI)] previously derived from river flow measurements across Europe. Using the same methods, total runoff simulated by three global hydrological models from the Water Model Intercomparison Project (WaterMIP) [Joint U.K. Land Environment Simulator (JULES), Water Global Assessment and Prognosis (WaterGAP), and Max Planck Institute Hydrological Model (MPI-HM)] run with the same meteorological input (watch forcing data) at the same spatial 0.5° grid was used to calculate simulated RDI and RFI for the period 1963–2001 in the same European regions, directly comparable with the observed catalogues. Observed and simulated RDI and RFI time series were compared using three performance measures: the relative mean error, the ratio between the standard deviation of simulated over observed series, and the Spearman correlation coefficient. Results show that all models can broadly reproduce the spatiotemporal evolution of hydrological extremes in Europe to varying degrees. JULES tends to produce prolonged, highly spatially coherent events for both high and low flows, with events developing more slowly and reaching and sustaining greater spatial coherence than observed—this could be due to runoff being dominated by slow-responding subsurface flow. In contrast, MPI-HM shows very high variability in the simulated RDI and RFI time series and a more rapid onset of extreme events than observed, in particular for regions with significant water storage capacity—this could be due to possible underrepresentation of infiltration and groundwater storage, with soil saturation reached too quickly. WaterGAP shares some of the issues of variability with MPI-HM—also attributed to insufficient soil storage capacity and surplus effective precipitation being generated as surface runoff—and some strong spatial coherence of simulated events with JULES, but neither of these are dominant. Of the three global models considered here, WaterGAP is arguably best suited to reproduce most regional characteristics of large-scale high and low flow events in Europe. Some systematic weaknesses emerge in all models, in particular for high flows, which could be a product of poor spatial resolution of the input climate data (e.g., where extreme precipitation is driven by local convective storms) or topography. Overall, this study has demonstrated that RDI and RFI are powerful tools that can be used to assess how well large-scale hydrological models reproduce large-scale hydrological extremes—an exercise rarely undertaken in model intercomparisons.
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Zhang, Chuan-Peng, Jin-Long Xu, Jie Wang, Yingjie Jing, Ziming Liu, Ming Zhu, and Peng Jiang. "Radio Frequency Interference Mitigation and Statistics in the Spectral Observations of FAST." Research in Astronomy and Astrophysics 22, no. 2 (February 1, 2022): 025015. http://dx.doi.org/10.1088/1674-4527/ac3f2d.
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Abstract In radio astronomy, radio frequency interference (RFI) becomes more and more serious for radio observational facilities. The RFI always influences the search and study of the interesting astronomical objects. Mitigating the RFI becomes an essential procedure in any survey data processing. The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is an extremely sensitive radio telescope. It is necessary to find out an effective and precise RFI mitigation method for FAST data processing. In this work, we introduce a method to mitigate the RFI in FAST spectral observation and make a statistic for the RFI using ∼300 h FAST data. The details are as follows. First, according to the characteristics of FAST spectra, we propose to use the Asymmetrically Reweighted Penalized Least Squares algorithm for baseline fitting. Our test results show that it has a good performance. Second, we flag the RFI with four strategies, which are to flag extremely strong RFI, flag long-lasting RFI, flag polarized RFI, and flag beam-combined RFI, respectively. The test results show that all the RFI above a preset threshold could be flagged. Third, we make a statistic for the probabilities of polarized XX and YY RFI in FAST observations. The statistical results could tell us which frequencies are relatively quiescent. With such statistical data, we are able to avoid using such frequencies in our spectral observations. Finally, based on the ∼300 h FAST data, we obtained an RFI table, which is the most complete database currently for FAST.
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Xie, Yunyi, Chao Miao, Yi Lu, Huizeng Sun, and Jianxin Liu. "Nitrogen metabolism and mammary gland amino acid utilization in lactating dairy cows with different residual feed intake." Animal Bioscience 34, no. 10 (October 1, 2021): 1600–1606. http://dx.doi.org/10.5713/ab.20.0821.
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Objective: This study was conducted to enhance our understanding of nitrogen (N) metabolism and mammary amino acid (AA) utilization in lactating cows with divergent phenotypes of residual feed intake (RFI).Methods: Fifty-three multiparous mid-lactation Holstein dairy cows were selected for RFI measurements over a 50-d experimental period. The 26 cows with the most extreme RFI values were classified into the high RFI (n = 13) and low RFI (n = 13) groups, respectively, for analysis of N metabolism and AA utilization.Results: Compared with the high RFI cows, the low RFI animals had lower dry matter intake (p<0.01) with no difference observed in milk yield between the two groups (p> 0.10). However, higher ratios of milk yield to dry matter intake (p<0.01) were found in the low RFI cows than in the high RFI cows. The low RFI cows had significant greater ratios of milk protein to metabolizable protein (p = 0.02) and milk protein to crude protein intake than the high RFI cows (p = 0.01). The arterial concentration and mammary uptake of essential AA (p<0.10), branched-chain AA (p<0.10), and total AA (p<0.10) tended to be lower in the low RFI cows. Additionally, the low RFI cows tended to have a lower ratio of AA uptake to milk output for essential AA (p = 0.08), branched-chain AA (p = 0.07) and total AA (p = 0.09) than the high RFI cows.Conclusion: In summary, both utilization of metabolizable protein for milk protein and mammary AA utilization are more efficient in cows with lower RFI than in the high RFI cows. Our results provide new insight into the protein metabolic processes (related to N and AA) involved in feed efficiency.
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Ding, Yi, Weiwei Fan, Zijing Zhang, Feng Zhou, and Bingbing Lu. "Radio Frequency Interference Mitigation for Synthetic Aperture Radar Based on the Time-Frequency Constraint Joint Low-Rank and Sparsity Properties." Remote Sensing 14, no. 3 (February 7, 2022): 775. http://dx.doi.org/10.3390/rs14030775.
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Synthetic aperture radar (SAR) is susceptible to radio frequency interference (RFI), which becomes especially commonplace in the increasingly complex electromagnetic environments. RFI severely detracts from SAR imaging quality, which hinders image interpretation. Therefore, some RFI mitigation algorithms have been introduced based on the partial features of RFI, but the RFI reconstruction models in these algorithms are rough and can be improved further. This paper proposes two algorithms for accurately modeling the structural properties of RFI and target echo signal (TES). Firstly, an RFI mitigation algorithm joining the low-rank characteristic and dual-sparsity property (LRDS) is proposed. In this algorithm, RFI is treated as a low-rank and sparse matrix, and the sparse matrix assumption is made for TES in the time–frequency (TF) domain. Compared with the traditional low-rank and sparse models, it can achieve better RFI mitigation performance with less signal loss and accelerated algorithm convergence. Secondly, the other RFI mitigation algorithm, named as TFC-LRS, is proposed to further reduce the signal loss. The TF constraint concept, in lieu of the special sparsity, is introduced in this algorithm to describe the structural distribution of RFI because of its aggregation characteristic in the TF spectrogram. Finally, the effectiveness, superiority, and robustness of the proposed algorithms are verified by RFI mitigation experiments on the simulated and measured SAR datasets.
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Cohen-Zinder, Miri, Aviv Asher, Ehud Lipkin, Roi Feingersch, Rotem Agmon, David Karasik, Arieh Brosh, and Ariel Shabtay. "FABP4is a leading candidate gene associated with residual feed intake in growing Holstein calves." Physiological Genomics 48, no. 5 (May 2016): 367–76. http://dx.doi.org/10.1152/physiolgenomics.00121.2015.
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Ecological and economic concerns drive the need to improve feed utilization by domestic animals. Residual feed intake (RFI) is one of the most acceptable measures for feed efficiency (FE). However, phenotyping RFI-related traits is complex and expensive and requires special equipment. Advances in marker technology allow the development of various DNA-based selection tools. To assimilate these technologies for the benefit of RFI-based selection, reliable phenotypic measures are prerequisite. In the current study, we identified single nucleotide polymorphisms (SNPs) associated with RFI phenotypic consistency across different ages and diets (named RFI 1–3), using DNA samples of high or low RFI ranked Holstein calves. Using targeted sequencing of chromosomal regions associated with FE- and RFI-related traits, we identified 48 top SNPs significantly associated with at least one of three defined RFIs. Eleven of these SNPs were harbored by the fatty acid binding protein 4 ( FABP4). While 10 significant SNPs found in FABP4 were common for RFI 1 and RFI 3, one SNP (FABP4_5; A<G substitution), in the promoter region of the gene, was significantly associated with all three RFIs. As the three RFI classes reflect changing diets and ages with concomitant RFI phenotypic consistency, the above polymorphisms and in particular FABP4_5, might be considered possible markers for RFI-based selection for FE in the Holstein breed, following a larger-scale validation.
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Oliveira, L. F., A. C. Ruggieri, R. H. Branco, O. L. Cota, R. C. Canesin, H. J. U. Costa, and M. E. Z. Mercadante. "Feed efficiency and enteric methane production of Nellore cattle in the feedlot and on pasture." Animal Production Science 58, no. 5 (2018): 886. http://dx.doi.org/10.1071/an16303.
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The objective of the present study was to assess the relationship between residual feed intake (RFI) evaluated in a feedlot-performance test and on pasture, and to determine the effect of feedlot RFI classification on enteric methane (CH4) production in the feedlot and on pasture. Seventy-three animals (25 with a low RFI, 24 with a medium RFI and 24 with a high RFI) classified in a feedlot performance test were subjected to performance testing on Brachiaria brizantha cv. Marandu pasture. Enteric CH4 was measured in a sample of these animals (n = 47, with high and low RFI) by the sulfur hexafluoride tracer-gas technique after the feedlot-performance test and during the performance test on pasture. In the feedlot-performance test, dry-matter intake (DMI) of low-RFI animals was 9.4% and 19.7% lower (P < 0.05) than that of medium- and high-RFI animals respectively. However, there was no difference in DMI and, consequently, in RFI on pasture among animals classified as low, medium and high RFI. Accordingly, there is evidence of re-ranking of animals for RFI performance tested in the feedlot after weaning and, subsequently, on pasture. During the period of enteric CH4 measurement in the feedlot and on pasture, the DMI, neutral detergent-fibre intake and gross-energy intake of low-RFI animals were lower than those of high-RFI animals, and low-RFI animals exhibited greater DM and neutral detergent fibre digestibility only in the feedlot. Enteric CH4 production did not differ between low- and high-RFI animals either in the feedlot (101 and 107 g CH4/day) or on pasture (101 and 95.9 g CH4/day). A significant difference in CH4 yield (CH4/kg DMI) was observed on pasture between animals with low and high RFI (17.6 and 13.7 g CH4/kg DMI respectively). The results did not support the hypothesis that an increase in feed efficiency, evaluated in growing animals in feedlot-performance tests, decreases enteric CH4 production (g/day) proportionally to the lower DMI.
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Holló, Gabriella, Henrietta Nagy-Kiszlinger, János Tossenberger, Márton Török, and Balázs Húth. "Individual Feed Efficiency Monitoring of Charolaise Candidate Young Bulls in Relation to Feeding Behavior and Self-Performance Test Results." Animals 12, no. 1 (December 24, 2021): 35. http://dx.doi.org/10.3390/ani12010035.
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This study evaluated the effect of differences in residual feed intake (RFI) of Charolaise candidate young bulls on feeding behavior and self-performance test results. Bulls were classified into high and low RFI (H-RFI, L-RFI) groups. Bulls were fed in a HOKOFARM system to measure individual animal intake and behavior. L-RFI bulls had significantly lower feed intakes (p = 0.002) and higher gain to feed ratio (p = 0.001), lower intake per day/kg DM (dry matter) (p = 0.002) and lower intake g/body weight/day (p < 0.001). L-RFI animals had lower visits number per day (p = 0.02), but spent longer time per visit (p = 0.02), and tended to have higher intake g/visit (p = 0.06) on feeders. The correlation between RFI and DMI (dry matter intake)/bodyweight/day as well as intake per day/kg were large and positive. Back-loin length and rump length, and moreover muzzle width and frame, showed negative correlations with RFI value. However, bulls with better RFI values associated with lower legs score. Results reveal that RFI was shown beneficial correlations with economically relevant self-performance traits. Further investigations are needed to seek additional indicator traits that are predictive for RFI.
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Wu, Xiaolong, Chong Feng, Qiyuan Li, and Jianping Zhu. "Keyword Pool Generation for Web Text Collecting: A Framework Integrating Sample and Semantic Information." Mathematics 12, no. 3 (January 26, 2024): 405. http://dx.doi.org/10.3390/math12030405.
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Keyword pools are used as search queries to collect web texts, largely determining the size and coverage of the samples and provide a data base for subsequent text mining. However, how to generate a refined keyword pool with high similarity and some expandability is a challenge. Currently, keyword pools for search queries aimed at collecting web texts either lack an objective generation method and evaluation system, or have a low utilization rate of sample semantic information. Therefore, this paper proposed a keyword generation framework that integrates sample and semantic information to construct a complete and objective keyword pool generation and evaluation system. The framework includes a data phase and a modeling phase, and its core is in the modeling phase, where both feature ranking and model performance are considered. A regression model about a topic vector and word vectors is constructed for the first time based on word embedding, and keyword pools are generated from the perspective of model performance. In addition, two keyword generation methods, Recursive Feature Introduction (RFI) and Recursive Feature Introduction and Elimination (RFIE), are also proposed in this paper. Different feature ranking algorithms, keyword generation methods and regression models are compared in the experiments. The results show that: (1) When using RFI to generate keywords, the regression model using ranked features has better prediction performance than the baseline model, and the number of generated keywords is refiner, and the prediction performance of the regression model using tree-based ranked features is significantly better than that of the one using SHAP-based ranked features. (2) The prediction performance of the regression model using RFI with tree-based ranked features is significantly better than that using Recursive Feature Elimination (RFE) with tree-based one. (3) All four regression models using RFI/RFE with SHAP- based/tree-based ranked features have significantly higher average similarity scores and cumulative advantages than the baseline model (the model using RFI with unranked features). (4) Light Gradient Boosting Machine (LGBM) using RFI with SHAP-based ranked features has significantly better prediction performance, higher average similarity scores, and cumulative advantages. In conclusion, our framework can generate a keyword pool that is more similar to the topic, and more refined and expandable, which provides certain research ideas for expanding the research sample size while ensuring the coverage of topics in web text collecting.
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Taiwo, Godstime A., Modoluwamu Idowu, Andres a. Pech-Cervantes, Zaira M. Estrada-Reyes, and Ibukun M. Ogunade. "PSVII-20 Hepatic Mrna Expression of Nutrient and Mitochondrial Energy Metabolism Genes in Beef Steers Selected for low or High Residual Feed Intake." Journal of Animal Science 100, Supplement_3 (September 21, 2022): 384. http://dx.doi.org/10.1093/jas/skac247.702.
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Abstract We evaluated the mRNA expression of genes involved in hepatic fatty acid, amino acid, and mitochondrial energy metabolism in crossbred beef steers with divergent low and high residual feed intake (RFI). Low-RFI beef steers (n = 8; RFI = - 1.93 kg/d) and high-RFI beef steers (n = 8; RFI = + 2.01kg/d) were selected from a group of 56 growing crossbred beef steers (average BW = 261 ± 18.5 kg) after a 49-d performance testing period. At the end of the 49-d period, liver biopsies were collected from the low-RFI and high-RFI beef steers for RNA extraction and cDNA synthesis. The mRNA expression of 84 genes each related to fatty acid metabolism, amino acid metabolism, and mitochondrial energy metabolism were analyzed using pathway-focused PCR-based arrays. The mRNA expression of genes with absolute fold change (FC) ≥ 2.0 having false discovery rate-adjusted P-values (FDR) ≤ 0.05 were considered to be differentially expressed. Eight genes (CRAT, SLC27A5, SLC27A2, ACSBG2, ACADL, ACADSB, ACAA1, and ACAA2) involved fatty acid transport and β-oxidation were upregulated in low-RFI, compared with high-RFI steers. Hepatic mRNA expression of a gene encoding for aminoadipate aminotransferase, an enzyme related to lysine degradation, was downregulated (FC = -5.45, P = 0.01) in low-RFI steers, whereas those of methionine adenosyltransferase I and aspartate aminotransferase 2, which both link amino acid and lipid metabolism, were upregulated. Two mitochondrial energy metabolism genes (UQCRC1 and ATP5G1) involved in ATP synthesis via oxidative phosphorylation were upregulated in low-RFI beef steers, compared with high-RFI beef steers. The results of this study demonstrated that low-RFI beef steers exhibit upregulation of molecular mechanisms related to fatty acid transport, fatty acid β-oxidation, and mitochondrial ATP synthesis, which suggest that low-RFI beef steers have enhanced metabolic capacity to maximize capture of energy and nutrients from feeds consumed.
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Taiwo, Godstime A., Modoluwamu Idowu, Mata Padrino Domingo Jose, James Denvir, and Ibukun M. Ogunade. "PSIX-16 Urine Metabolome and Whole Blood Transcriptome of Beef Steers with low or High Residual Feed Intake." Journal of Animal Science 100, Supplement_3 (September 21, 2022): 372. http://dx.doi.org/10.1093/jas/skac247.680.
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Abstract We analyzed the metabolome of urine samples to identify urinary metabolic biomarkers and whole blood transcriptome-based gene set enrichment to identify key pathways associated with divergent selection for low or high RFI in beef cattle. Low-RFI beef steers (n = 8; RFI = - 1.93 kg/d) and high-RFI beef steers (n = 8; RFI = + 2.01kg/d) were selected from a group of 56 growing crossbred beef steers after a 49-d performance testing period. At the end of the 49-d period, weekly urine and blood samples were collected three times from the low- and high-RFI steers. Metabolome analysis of the urine samples was conducted using a liquid chromatography–mass spectrometer and biomarker analysis of the metabolome data was performed to identify candidate biomarkers (FDR ≤ 0.05; AUC ≥ 0.85) associated with RFI. Whole-blood RNA sequencing was performed on an Illumina sequencer and gene set enrichment analysis (GSEA) was used to analyze differentially expressed (FDR ≤ 0.05) pathways. A total number of 557 metabolites were detected and identified. Biomarker analysis of the metabolome data identified N-acetyl-L-tyrosine, O-methyl-L-threonine, uridine, and threoninyl-hydroxyproline as candidate biomarkers (FDR ≤ 0.05; AUC > 0.85) of RFI. Results of GSEA revealed pathways associated with protein metabolism, cellular responses to external stimuli, and stress were differentially inhibited in high-RFI compared with low-RFI beef cattle, while pathways associated with binding and uptake of ligands by scavenger receptors and erythrocytes release/take up oxygen were differentially enriched (FDR < 0.05) in high-RFI beef steers. Taken together, our results revealed that urine is a potential source of metabolite biomarkers associated with RFI and beef steers divergently selected for low or high RFI have differential expressions of genes related to protein metabolism and stress responsiveness. high RFI revealed differential expressions of genes related to protein metabolism and stress responsiveness.
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Wang, Xinxin, Xiang Wang, Lin Wang, Jianchao Fan, and Enbo Wei. "Constrained Iterative Adaptive Algorithm for the Detection and Localization of RFI Sources Based on the SMAP L-Band Microwave Radiometer." Remote Sensing 16, no. 10 (May 18, 2024): 1791. http://dx.doi.org/10.3390/rs16101791.
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The Soil Moisture Active Passive (SMAP) satellite carries an L-band microwave radiometer. This sensor can be used to observe global soil moisture (SM) and sea surface salinity (SSS) within the protected L-band spectrum (1400–1427 MHz). Owing to the complex effects of radio frequency interference (RFI), the SM and SSS data are missing or have low accuracy. In this paper, a constrained iterative adaptive algorithm for the detection, identification, and localization of RFI sources is designed, named MICA-BEID. The algorithm synthesizes antenna temperatures for the third and fourth Stokes parameters before RFI filtering, creating a new polarization parameter called WSPDA, designed to approximate the level of RFI interference on the L-band microwave radiometer. The algorithm then utilizes the WSPDA intensity and distribution density of RFI detection samples to enhance the identification and classification of RFI sources across various intensity levels. By utilizing statistical methods such as the probability density function (PDF) and the cumulative distribution function (CDF), the algorithm dynamically adjusts adaptive parameters, including the RFI detection threshold and the maximum effective radius of RFI sources. Through the application of multiple iterative clustering methods, the algorithm can adaptively detect and identify RFI sources at various satellite orbits and intensity levels. Through extensive comparative analysis with other localization results and known RFI sources, the MICA-BEID algorithm can achieve optimal localization accuracy of approximately 1.2 km. The localization of RFI sources provides important guidance for identifying and turning off illegal RFI sources. Moreover, the localization and long-time-series characteristic analysis of RFI sources that cannot be turned off is of significant value for simulating the spatial distribution characteristics of localized RFI source intensity in local areas.
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Lines, D. S., W. S. Pitchford, C. D. K. Bottema, R. M. Herd, and V. H. Oddy. "Selection for residual feed intake affects appetite and body composition rather than energetic efficiency." Animal Production Science 58, no. 1 (2018): 175. http://dx.doi.org/10.1071/an13321.
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Residual feed intake (RFI) is the difference between an animal’s actual feed intake and that which would be expected based on production. This experiment was to test the hypothesis that part of the variation in RFI may be due to differences in energetic efficiency through changes in heat production, these being in part due to differences in protein metabolism. Following three generations of divergent selection for RFI, eight High and eight Low-RFI heifers were fed at both 105% and 180% of predicted maintenance feed requirements. Between-RFI line and feeding-level differences were assessed for energy intake, protein metabolism, heat production, body composition, energy and nitrogen balance and digestibility. The RFI lines did not differ in protein metabolism or heat production. The High-RFI heifers deposited 51% and 56% more subcutaneous fat at the P8 rump and 12/13th rib sites, respectively, with no difference in eye muscle area gain or average daily weight gain. The greater fat deposition of High-RFI heifers was due to a larger ad libitum feed consumption compared with the Low-RFI heifers. Energy and nitrogen balance did not differ between the RFI lines. The energy transactions indicated no difference in the efficiency of energy use on 105% maintenance, although when fed 180% of maintenance the differences in feed intake suggest variation in appetite as the mechanism contributing to RFI. All of the extra energy consumed by High-RFI heifers above maintenance and deposition of protein was associated with additional energy retained as fat. This study suggests that selection for RFI may not lead to improved efficiency of energy use.
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Taiwo, Godstime, Modoluwamu Idowu, Taylor Sidney, Emily Treon, Deborah Ologunagba, Yarahy Leal, Samanthia Johnson, et al. "1H-NMR-Based Plasma Metabolomic Profiling of Crossbred Beef Cattle with Divergent RFI Phenotype." Ruminants 4, no. 2 (April 8, 2024): 182–91. http://dx.doi.org/10.3390/ruminants4020012.
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This study focused on exploring the metabolomic profiles of crossbred beef cattle with varying levels of residual feed intake (RFI), a measure of feed efficiency in beef cattle. Sixty-seven crossbred growing beef steers (BW = 277 ± 29.7 kg) were subjected to a high-forage total mixed ration for 64 days to determine their RFI phenotypes. At the end of the 64d feeding trial, beef steers were divided into two groups based on their RFI values: low (or negative)-RFI beef steers (n = 28; RFI = −1.08 ± 0.88 kg/d) and high (or positive)-RFI beef steers (n = 39; RFI = 1.21 ± 0.92 kg/d). Blood samples were collected, and plasma samples were analyzed using Nuclear Magnetic Resonance spectroscopy, resulting in the identification of 50 metabolites. The study found a distinct metabolomic signature associated with RFI status. Eight metabolites, including amino acids (tyrosine, glycine, valine, leucine, and methionine) and other compounds (dimethyl sulfone, 3-hydroxy isovaleric acid, citric acid, creatine, and L-carnitine), showed differential abundance between low- and high-RFI groups. Specifically, tyrosine, glycine, and dimethyl sulfone exhibited significant specificity and sensitivity, which produced a discriminatory model with an area under the receiver operating characteristic (ROC) curve of 0.7, making them potential markers for RFI. A logistic regression model incorporating these biomarkers effectively distinguished between high- and low-RFI steers, with a threshold cutoff point of 0.48, highlighting a distinctive metabolite profile associated with efficient nutrient utilization in low-RFI cattle. The logistic regression model, incorporating these biomarkers, holds promise for accurately categorizing RFI values, providing insights into the metabolic basis of feed efficiency in beef cattle.
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REIS, Simone Frotas dos, Daiane Aparecida FAUSTO, Sergio Raposo de MEDEIROS, Pedro Veiga Rodrigues PAULINO, Sebastião de Campos VALADARES FILHO, and Roberto Augusto de Almeida TORRES JÚNIOR. "Feed efficiency and meat quality of crossbred beef heifers classified according to residual feed intake." Revista Brasileira de Saúde e Produção Animal 16, no. 3 (September 2015): 632–42. http://dx.doi.org/10.1590/s1519-99402015000300014.
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AbstractThis study aimed to evaluate feed efficiency and meat quality of 31 three-crossbred beef heifers during 84 days in a feedlot system. A 60:40 concentrate and sorghum silage ration on DM basis (ME = 2.73Mcal/kg of DM, CP = 11.90% DM) was fed ad libitum. Based on residual feed intake (RFI) calculations, the heifers were ranked in three groups of feed efficiency: High RFI (average mean = 0.776; n = 9), medium RFI (average mean = -0.010; n = 11), and low RFI (average mean = - 0.624; n = 11). High RFI heifers consumed 4.56% more DM per day than low RFI heifers (P <0.05). The ADG did not differ (P> 0.05) among RFI groups (1.40kg/day). No differences (P>0.05) were detected for digestibility of the nutrients: DM (64.00%), CP (60.01%), crude fat (72.90%), NDF (54.80%) and non-fibrous carbohydrate (NFC) (78.91%). There were no differences between low and high RFI groups for slaughter weight (475.00 vs. 479.55kg), hot carcass weight (259.09 vs. 261.44kg), Longissimus dorsi (LD) area (69.02 vs. 68.11 cm2), back-fat thickness (5.74 vs. 6.26 cm), shear force (5.45 vs. 5.19kg), sensorial traits of LD muscle, LD color (intensities L=40.47 a*=24.74 and b*=16.13) or commercial cuts yield. Low RFI heifers presented similar meat quality and carcass traits as high RFI heifers, however low RFI heifers consumed less DM (kg/d).
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Adcock, Zoe, Keara O’Reilly, Gordon E. Carstens, Luis O. Tedeschi, William E. Pinchak, and Ryon S. Walker. "PSV-30 Effects of divergent residual feed intake on performance, feed efficiency, feeding behavior and gaseous exchange in replacement beef heifers." Journal of Animal Science 102, Supplement_3 (September 1, 2024): 739. http://dx.doi.org/10.1093/jas/skae234.833.
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Abstract The objective of this study was to examine the differences in performance, feed efficiency, feeding behavior and gaseous exchange (methane, carbon dioxide and oxygen) in replacement beef heifers with divergent phenotypes for residual feed intake (RFI). Crossbred beef replacement heifers [n = 63; initial body weight (BW) = 277 ± 21 kg] were blocked by BW and assigned to 1 of 2 pens each equipped with electronic feed bunks (GrowSafe Systems) and GreenFeed gaseous-exchange measurement systems (GEM; C-Lock). Heifers were fed a corn-silage based ration twice daily. Individual dry matter intake (DMI), feeding behavior, and gas flux data were collected for 70 d and BW measured weekly. Carcass ultrasound data were collected at the beginning and end of the study. Residual feed intake was calculated as the residual from the regression of DMI on ADG and mid-test BW0.75 and heifers assigned to low-, medium-, and high-RFI classes (± 0.5 SD from the mean RFI). A mixed model with RFI class as fixed effect and pen as a random effect was used for data analysis. There were no differences due to RFI class in BW and ADG. However, low-RFI heifers consumed 16% less (P < 0.001) DMI and had more favorable gain to feed (G:F) then high-RFI heifers. High-RFI heifers had a greater (P < 0.05) backfat gain during the 70-d study, with backfat gain accounting for an additional 4.2% of the variation in DMI. Low-RFI heifers exhibited more favorable feeding behavior, with 10.4% fewer (P = 0.057) bunk visit events and spent numerically less time at the feed bunk (103 vs 122 min/d) compared with high-RFI heifers. Methane emissions (g/d) did not differ between heifers with divergent RFI (P = 0.138; 129 vs 140 g/d in low- and high RFI heifers respectively), however, methane yield (g/kg DMI) was 9% greater (P < 0.05) in low- compared with high-RFI heifers. Additionally, low-RFI heifers produced 7.9% less (P < 0.05) carbon dioxide (g/d) and consumed 6.9% less (P < 0.05) oxygen than high RFI heifers. Further research is warranted to investigate the biological mechanisms influencing RFI and the effects of selection for RFI as a strategy to mitigate reduce greenhouse gas emissions from cattle production systems.
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Deal, Derod, and Preshanth Jagannathan. "Segmenting RFI Using Meta’s Segment Anything Model." Research Notes of the AAS 8, no. 10 (October 14, 2024): 257. http://dx.doi.org/10.3847/2515-5172/ad84fa.
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Abstract Radio Frequency Interference (RFI), radio signals from electronics, permeates through astronomical observations using radio telescopes. The interference results in lower sensitivity and higher noise when present. Existing methods, such as TFCrop and RFlag, flag RFI to prevent the contamination of observations. However, these approaches are partially automatic and require manual input to flag RFI. We explore artificial intelligence methods using Meta’s Segment Anything Model (SAM) and its parameter space in segmenting RFI. We have developed an open-source pipeline called SamRFI, which segments and flags RFI from measurement sets. We trained SAM’s masking weights from Hugging Face to fine-tune the model using Very Large Array data and synthetic waterfall plots injected with RFI. We define a metric, calcquality, to measure the performance of our models based on sensitivity and overflagging. Retrained SAM models identify RFI structure and allow for further exploration in RFI segmentation.
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Basnet, Pawan, Sharon A. Clay, and Emmanuel Byamukama. "Reproduction of Soybean Cyst Nematode Populations on Field Pennycress, Henbit, and Purple Deadnettle Weed Hosts." Agronomy 12, no. 9 (August 26, 2022): 2027. http://dx.doi.org/10.3390/agronomy12092027.
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Several weeds serve as alternative soybean cyst nematode (SCN) hosts. Still, the relative reproductive capacity of SCN HG types (Heterodera glycines type) on weed hosts relative to soybean is not well understood. This study examined the reproduction of three South Dakota endemic SCN populations—PSCN-1 (HG 0), PSCN-2 (HG 2.5.7), and PSCN-3 (HG 7)—on purple deadnettle, field pennycress, and henbit. The Relative Female Index (RFI) was calculated to compare SCN reproduction relative to the susceptible soybean check. Weed hosts, HG types, and their interactions influenced SCN reproduction. Henbit (RFI = 51.8) and purple deadnettle (RFI = 47.6) roots had a similar high RFI, whereas field pennycress (RFI = 23.04) had a lower RFI. Similarly, SCN populations PSCN-1 and PSCN-3 had a similar RFI of 36.9 and 37.2, respectively, while the population PSCN-2 had a higher RFI of 44.9 across weed hosts. A significant interaction between PSCN-1 and purple deadnettle was observed where the RFI was the highest (RFI = 53.3). These results indicate that these weed hosts support endemic SCN populations, and the HG type influenced reproductive success, further complicating SCN management. Hence, SCN presents a significant challenge in the new prospect of incorporating field pennycress host as an oilseed cover crop in the Midwest’s corn–soybean production system.
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Acetoze, G., K. L. Weber, J. J. Ramsey, and H. A. Rossow. "Relationship between Liver Mitochondrial Respiration and Proton Leak in Low and High RFI Steers from Two Lineages of RFI Angus Bulls." International Scholarly Research Notices 2015 (April 23, 2015): 1–5. http://dx.doi.org/10.1155/2015/194014.
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The objective of this research is to evaluate liver mitochondrial oxygen consumption and proton leak kinetics in progeny from two lineages of Angus bulls with high and low residual feed intake (RFI). Two Angus bulls were selected based on results from a genetic test for RFI and were used as sires. Eight offspring at 10-11 months of age from each sire were housed in individual pens for 70–105 days following a diet adaptation period of 14 days. Progeny of the low RFI sire had 0.57 kg/d (P=0.05) lower average RFI than progeny of the high RFI sire. There was no difference in dry matter intake between low and high RFI steers, but low RFI steers gained more body weight (P=0.02) and tended to have higher average daily gains (P=0.07). State 3 and State 4 respiration, RCR, and proton leak did not differ between high and low RFI steers (P=0.96, P=0.81, P=0.93, and P=0.88, resp.). Therefore, the increase in bodyweight gain which distinguished the low RFI steers from the high RFI steers may be associated with other metabolic mechanisms that are not associated with liver mitochondrial respiration and proton leak kinetics.
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Wu, Ying, Bo Qian, Yansong Bao, Meixin Li, George P. Petropoulos, Xulin Liu, and Lin Li. "Detection and Analysis of C-Band Radio Frequency Interference in AMSR2 Data over Land." Remote Sensing 11, no. 10 (May 23, 2019): 1228. http://dx.doi.org/10.3390/rs11101228.
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A simplified generalized radio frequency interference (RFI) detection method and principal component analysis (PCA) method are utilized to detect and attribute the sources of C-band RFI in AMSR2 L1 brightness temperature data over land during 1–16 July 2017. The results show that the consistency between the two methods provides confidence that RFI may be reliably detected using either of the methods, and the only difference is that the scope of the RFI-contaminated area identified by the former algorithm is larger in some areas than that using the latter method. Strong RFI signals at 6.925 GHz are mainly distributed in the United States, Japan, India, Brazil, and some parts of Europe; meanwhile, RFI signals at 7.3 GHz are mainly distributed in Latin America, Asia, Southern Europe, and Africa. However, no obvious 7.3 GHz RFI appears in the United States or India, indicating that the 7.3 GHz channels mitigate the effects of the C-band RFI in these regions. The RFI signals whose position does not vary with the Earth azimuth of the observations generally come from stable, continuous sources of active ground-based microwave radiation, while the RFI signals which are observed only in some directions on a kind of scanning orbit (ascending/descending) mostly arise from reflected geostationary satellite signals.
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Johnson, Chinju, Carolyn Fitzsimmons, Marcos Colazo, Changxi Li, John Kastelic, and Jacob Thundathil. "Impacts of residual feed intake and pre-natal diet on reproductive potential of bulls." Animal Production Science 59, no. 10 (2019): 1827. http://dx.doi.org/10.1071/an18301.
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Our objective was to determine effects of genetic potential for residual feed intake (RFI) and pre-natal diet on post-natal growth and reproductive development of bulls. Twenty-five bull calves with a divergent potential for RFI were produced by mating purebred Angus heifers (60) categorised as high or low RFI and inseminated with semen from high or low RFI bulls. From 30 to 150 days of gestation, half the heifers (balanced for RFI across treatments) in each RFI category were fed to gain 0.7 or 0.5 kg/day (~100% and 75% of recommended feed intake; designated normal- and low-diet, respectively). Birthweights of bull calves (n = 25) did not differ significantly among treatment groups (P ≥ 0.1). However, there was a tendency (P < 0.1) for a maternal diet*time interaction for bull weights, with bulls from low pre-natal diet fed heifers growing faster between 10 and 16 months of age than bulls from normal pre-natal diet fed heifers. Furthermore, high-RFI bulls had a larger scrotal circumference (P < 0.01) and attained puberty (P < 0.05) earlier than low-RFI bulls. Other testes measures, including paired testes volume, epididymal sperm reserves, daily sperm production and total sperm production, were not significantly different among treatment groups (P ≥ 0.1). High RFI bulls tended (P < 0.1) to have better average sperm motility than low RFI bulls. However, sperm morphology, viability and chromatin damage were not different (P ≥ 0.1). In summary, young beef bulls with low RFI had smaller testis, delayed onset of puberty (~1.7 months) and tended to exhibit lower progressive motility compared with high RFI bulls. Pre-natal diet had no direct influence on male reproductive development, nor did it interact with RFI of bulls.
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Yang, Zhicheng, Ce Yu, Jian Xiao, and Bo Zhang. "Deep residual detection of radio frequency interference for FAST." Monthly Notices of the Royal Astronomical Society 492, no. 1 (January 11, 2020): 1421–31. http://dx.doi.org/10.1093/mnras/stz3521.
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ABSTRACT Radio frequency interference (RFI) detection and excision are key steps in the data-processing pipeline of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Because of its high sensitivity and large data rate, FAST requires more accurate and efficient RFI flagging methods than its counterparts. In the last decades, approaches based upon artificial intelligence (AI), such as codes using convolutional neural networks (CNNs), have been proposed to identify RFI more reliably and efficiently. However, RFI flagging of FAST data with such methods has often proved to be erroneous, with further manual inspections required. In addition, network construction as well as preparation of training data sets for effective RFI flagging has imposed significant additional workloads. Therefore, rapid deployment and adjustment of AI approaches for different observations is impractical to implement with existing algorithms. To overcome such problems, we propose a model called RFI-Net. With the input of raw data without any processing, RFI-Net can detect RFI automatically, producing corresponding masks without any alteration of the original data. Experiments with RFI-Net using simulated astronomical data show that our model has outperformed existing methods in terms of both precision and recall. Besides, compared with other models, our method can obtain the same relative accuracy with fewer training data, thus reducing the effort and time required to prepare the training data set. Further, the training process of RFI-Net can be accelerated, with overfittings being minimized, compared with other CNN codes. The performance of RFI-Net has also been evaluated with observing data obtained by FAST and the Bleien Observatory. Our results demonstrate the ability of RFI-Net to accurately identify RFI with fine-grained, high-precision masks that required no further modification.
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BABAN, BHONG N., CHANDER DATT, PH SURAJ SHARMA, KULDEEP DUDI, and VIJAY K. SHARMA. "Residual feed intake and related biochemical parameters in male Sahiwal calves." Indian Journal of Animal Sciences 90, no. 10 (April 5, 2021): 1423–29. http://dx.doi.org/10.56093/ijans.v90i10.111420.
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This study was conducted to evaluate the differences in efficiency of feed utilisation in Sahiwal calves with low and high residual feed intake (RFI) by comparing feed intake, nutrient digestibility, growth traits and blood biochemical parameters. Eighteen growing male Sahiwal calves (aged 12 months, average body weight 120.04 kg) were selected and fed individually total mixed ration as per their requirements for a period of 60 days. Fifty per cent of maize grains in concentrate mixture containing 33% maize grains were replaced by fresh potatoes (DM basis). Based on linear regression models involving dry matter intake (DMI), average daily gain (ADG) and mid test metabolic body size, calves were assigned into low and high RFI groups. Residual feed intake (RFI) values were calculated for individual calves and the calves were divided into low (–0.20) and high (+0.18) RFI groups. Low RFI animals consumed less dry matter than the expected or predicted one indicating their more efficiency of feed utilization. The intakes of DM and CP were 4.95 and 6.47% lower in low RFI animals compared to high RFI animals while average daily gain was higher in low RFI group. The digestibility of DM, OM, CP, EE, total carbohydrates, NDF and ADF were similar in low and high RFI groups, however, nitrogen retention was higher in low RFI group. Values of alanine amino transferase (25.85 vs. 35.72 IU/L), aspartate amino transferase (80.33 vs. 100.57 IU/L), total protein (7.34 and 8.24 mg/dL), blood urea nitrogen (15.45 and 22.22 mg/dL) and creatinine (1.27 and 1.78 mg/dL) were higher for high RFI as compared to low RFI group. The concentration of growth hormone, insulin and IGF-1 were similar in both the groups. From present study, it could be concluded that low RFI animals were more efficient in feed conversion.
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Idowu, Modoluwamu, Godstime A. Taiwo, Taylor S. Sidney, Emily Treon, Deborah Ologunagba, Yara Leal, Francisca Eichie, Lanre Morenikeji, Andres A. Pech-Cervantes, and Ibukun M. Ogunade. "PSV-10 Effects of Rumen-Bypass Protein Supplement on Growth Performance, Hepatic Mitochondrial Function and Immune Gene Expression of Beef Steers with Divergent Residual Feed Intake Phenotype." Journal of Animal Science 101, Supplement_3 (November 6, 2023): 400–401. http://dx.doi.org/10.1093/jas/skad281.476.
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Abstract We examined the effects of rumen-bypass protein supplement on growth performance, hepatic mitochondrial Electron Transport Chain (ETC) activities, and mRNA expression of innate and adaptive immune genes of beef steers with divergent residual feed intake (RFI) phenotype. Thirty-nine crossbred beef steers (average BW = 492 ± 36 kg) were used in a generalized randomized block design with a 2 × 2 factorial arrangement of treatments for a 42-d experimental period. The factors evaluated were 1) RFI classification [low-RFI (-2.12kg/d) vs. high-RFI (2.02kg/d)], and 2) feed additive: rumen-bypass protein supplement (RCP; 227 g· steer-1· day-1) vs. Control diet (CON; 0 g/d), resulting in four treatments: Low-RFI-CON (n = 10), low-RFI-RCP (n = 9), high-RFI-CON (n = 10), and high-RFI-RCP (n = 10). The rumen-bypass protein supplement (84% CP) is a blend of hydrolyzed feather meal, porcine blood meal, and DL-methionine hydroxy analogue. The beef steers were stratified by BW and randomly assigned to treatments and housed in four pens equipped with two GrowSafe feed bunks each to measure individual DMI. Body weight was measured every 7 days. Liver tissue was sampled on d 42 from all animals using a liver biopsy needle for mRNA expression analysis of 84 immune genes and analysis of mitochondrial ETC activities of complexes I – V. No effects of supplemental feed additive or RFI × feed additive interactions were observed (P > 0.05) for ADG and DMI. Compared with high-RFI, low-RFI beef steers tended to have less DMI (13.6 vs 12.9 kg/d; P = 0.09) but ADG was similar for the two RFI groups. Feed additive × RFI interactions were observed (P ≤ 0.05) for mitochondrial activities of Complexes IV, V, and mRNA expressions of some immune genes. Supplemental RCP increased Complex IV (39.2 nmol/min/mg) activity and reduced that of Complex V (94.1 nmol· min-1· mg-1) in high-RFI beef steers whereas the activity of Complex IV (13.1 nmol· min-1· mg-1) was reduced and that of Complex V (120 nmol· min-1· mg-1) was increased in low-RFI beef steers. Supplemental RCP increased (P < 0.05) the mRNA expression of TLR2 [fold change (FC) = 1.17 vs 0.98], TLR3 (FC = 1.49 vs 0.97), NFKB1 (FC = 1.02 vs 0.90), and IL23A (FC = 1.35 vs 1.07) in high-RFI beef steers but the expression of these genes were not altered in low-RFI beef steers. In conclusion, RCP supplementation did not affect the growth performance and the observed effects on hepatic immune gene expression and activities of mitochondrial ETC complexes are dependent on the RFI phenotype of the beef steers. Further research should explore the mechanism responsible for the interactions between RCP supplementation and RFI status.
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Silvestre, Antonio M., Ana Carolina J. Pinto, Werner F. Schleifer, Lidiane S. Miranda, Leandro A. F. Silva, Daniel M. Casali, Katia L. R. Souza, et al. "Relationships of the Microbial Communities with Rumen Epithelium Development of Nellore Cattle Finished in Feedlot Differing in Phenotypic Residual Feed Intake." Animals 12, no. 7 (March 24, 2022): 820. http://dx.doi.org/10.3390/ani12070820.
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The objective of this study was to examine the relationships among ruminal microbial community, rumen morphometrics, feeding behavior, feedlot performance, and carcass characteristics of Nellore cattle, classified by residual feed intake (RFI). Twenty-seven Nellore yearling bulls with an initial body weight (BW) of 423.84 ± 21.81 kg were fed in feedlot for 107 d in individual pens to determine the RFI phenotype. Bulls were categorized as high RFI (>0.5 SD above the mean, n = 8), medium RFI (±0.5 SD from the mean, n = 9), and low RFI (<0.5 SD below the mean, n = 10). At harvest, whole rumen content samples were collected from each bull to evaluate ruminal microbial community, including bacteria and protozoa. The carcass characteristics were determined by ultrasonography at the beginning and at the end of the experimental period, and behavior data were collected on d 88. As a result of ranking Nellore bulls by RFI, cattle from low-RFI group presented lesser daily dry matter intake (DMI), either in kilograms (p < 0.01) or as percentage of BW (p < 0.01) than high-RFI yearling bulls, resulting in improved gain:feed (G:F). However, variables, such as average daily gain (ADG), final BW, hot carcass weight (HCW) and other carcass characteristics did not differ (p > 0.05) across RFI groups. The eating rate of either dry matter (DM )(p = 0.04) or neutral detergent fiber (NDF) (p < 0.01) was slower in medium-RFI yearling bulls. For ruminal morphometrics an RFI effect was observed only on keratinized layer thickness, in which a thinner layer (p = 0.04) was observed in low-RFI Nellore yearling bulls. Likewise, Nellore yearling bulls classified by the RFI did not differ in terms of Shannon’s diversity (p = 0.57) and Chao richness (p = 0.98). Our results suggest that the differences in feed efficiency of Nellore bulls differing in phenotypic RFI should be attributed to metabolic variables other than ruminal microorganisms and epithelium, and deserves further investigation.
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Wang, Yu-Chen, Zhen-Zhao Tao, Zhi-Song Zhang, Cheqiu Lyu, Tingting Zhang, Tong-Jie Zhang, and Dan Werthimer. "A Search for Extraterrestrial Technosignatures in Archival FAST Survey Data Using a New Procedure." Astronomical Journal 166, no. 4 (September 6, 2023): 146. http://dx.doi.org/10.3847/1538-3881/acf12a.
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Abstract The search for extraterrestrial intelligence (SETI) commensal surveys aim to scan the sky to find possible technosignatures from an extraterrestrial intelligence (ETI). The mitigation of radio frequency interference (RFI) is an important step, especially for the most sensitive Five-hundred-meter Aperture Spherical radio Telescope (FAST), which can detect more weak RFI. In this paper, we propose several new techniques for RFI mitigation and use our procedure to search for ETI signals from the archival data of FAST’s first SETI commensal survey. We detect the persistent narrowband RFI by setting a threshold of the signals’ sky separation and detect the drifting RFI (and potentially other types of RFI) using the Hough transform. We also use the clustering algorithms to remove more RFI and select candidates. The results of our procedure are compared to the earlier work on the same FAST data. We find that our methods, though relatively simpler in computation, remove more RFI (99.9912% compared to 99.9063% in the earlier work) but preserve the simulated ETI signals, except for those (5.1%) severely affected by the RFI. We also report more interesting candidate signals, about a dozen of which are new candidates that were not previously reported. In addition, we find that the proposed Hough transform method, with suitable parameters, also has the potential to remove the broadband RFI. We conclude that our methods can effectively remove the vast majority of the RFI while preserving and finding the candidate signals that we are interested in.
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Yu, Junfei, Jingwen Li, Bing Sun, Yuming Jiang, and Liying Xu. "Multiple RFI Sources Location Method Combining Two-Dimensional ESPRIT DOA Estimation and Particle Swarm Optimization for Spaceborne SAR." Remote Sensing 13, no. 6 (March 22, 2021): 1207. http://dx.doi.org/10.3390/rs13061207.
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Synthetic aperture radar (SAR) systems are susceptible to radio frequency interference (RFI). The existence of RFI will cause serious degradation of SAR image quality and a huge risk of target misjudgment, which makes the research on RFI suppression methods receive widespread attention. Since the location of the RFI source is one of the most vital information for achieving RFI spatial filtering, this paper presents a novel location method of multiple independent RFI sources based on direction-of-arrival (DOA) estimation and the non-convex optimization algorithm. It deploys an L-shaped multi-channel array on the SAR system to receive echo signals, and utilizes the two-dimensional estimating signal parameter via rotational invariance techniques (2D-ESPRIT) algorithm to estimate the positional relationship between the RFI source and the SAR system, ultimately combines the DOA estimation results of multiple azimuth time to calculate the geographic location of RFI sources through the particle swarm optimization (PSO) algorithm. Results on simulation experiments prove the effectiveness of the proposed method.
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Dyson, T., H. C. Chiang, E. Egan, N. Ghazi, T. Ménard, R. A. Monsalve, T. Moso, J. Peterson, J. L. Sievers, and S. Tartakovsky. "Radio-Frequency Interference at the McGill Arctic Research Station." Journal of Astronomical Instrumentation 10, no. 02 (May 12, 2021): 2150007. http://dx.doi.org/10.1142/s2251171721500070.
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The frequencies of interest for redshifted 21[Formula: see text]cm observations are heavily affected by terrestrial radio-frequency interference (RFI). We identify the McGill Arctic Research Station (MARS) as a new RFI-quiet site and report its RFI occupancy using 122[Formula: see text]h of data taken with a prototype antenna station developed for the Array of Long-Baseline Antennas for Taking Radio Observations from the Sub-Antarctic. Using an RFI flagging process tailored to the MARS data, we find an overall RFI occupancy of 1.8% averaged over 20–125[Formula: see text]MHz. In particular, the FM broadcast band (88–108[Formula: see text]MHz) is found to have an RFI occupancy of at most 1.6%. The data were taken during the Arctic summer, when degraded ionospheric conditions and an active research base contributed to increased RFI. The results quoted here therefore represent the maximum-level RFI environment at MARS.
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Wu, Ying, Meixin Li, Yansong Bao, and George P. Petropoulos. "Cross-Validation of Radio-Frequency-Interference Signature in Satellite Microwave Radiometer Observations over the Ocean." Remote Sensing 12, no. 20 (October 19, 2020): 3433. http://dx.doi.org/10.3390/rs12203433.
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Radio-frequency-interference (RFI) signals have gradually become a more serious problem in active and passive microwave remote sensing. However, currently, there is no reliable RFI source distribution data to evaluate the accuracy of existing RFI identification methods. In this study, a simplified generalized RFI detection method (GRDM) is proposed to detect RFI applied to the ocean surface. Two RFI detection methods, the GRDM and the double-principal component analysis (DPCA) method, are used for cross-validation to obtain RFI recognition thresholds of DPCA in the Advanced Microwave Scanning Radiometer 2 (AMSR2) ocean data. In addition, in the present work the source and distribution characteristics of RFI over the ocean surface are also analyzed. The results show that the proposed scheme can effectively identify RFI signals from AMSR2 data, and only 7.3, 10.65, and 18.7 GHz channels are contaminated by RFI over the ocean surface. There are strong 7.3 GHz interference signals over the waters of East Asia (with the value of ΔTBH mostly between 5 and 30 K and ΔTBv mostly between 5 and 40 K), Europe (with the value of ΔTBH mostly between 5 and 40 K and ΔTBv mostly between 5 and 30 K), and North America (with the value of ΔTBH mostly between 5 and 50 K and ΔTBv mostly between 5 and 30 K). The RFI signals in 10.65 GHz data are mainly distributed over the Mediterranean and other European waters (with the value of ΔTBH mostly between 5 and 35 K and ΔTBv mostly between 5 and 20 K). The RFI signals at 18.7 GHz are mainly present over the offshore marine areas of North America (with the value of ΔTBH mostly between 5 and 50 K and ΔTBv mostly between 5 and 40 K), with the strongest RFI distributed near the Great Lakes of America, and the RFI magnitudes over the east and west coasts are stronger than over the south coast. Satellite-borne microwave observations over the ocean suffer from interference mainly from stationary communication/television satellites. Due to the reflection of the sea surface, the range and intensity of RFI are strongly dependent on the relative geometric positions of stationary satellites and space-borne passive instruments. Therefore, RFI coverage area changes every day over the ocean in one 16-day period, which is very different from that over the land.
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Wang, Zijian, Wenbo Yu, Jiamu Li, Zhongjun Yu, Yao Zhao, and Yunhua Luo. "Radio Frequency Interference Mitigation in Synthetic Aperture Radar Data Based on Instantaneous Spectrum Forward Consecutive Mean Excision." Remote Sensing 16, no. 1 (December 29, 2023): 150. http://dx.doi.org/10.3390/rs16010150.
Full textAbstract:
Radio frequency interference (RFI) poses major threats to synthetic aperture radar (SAR) systems. Due to the suppression of useful target signals via high-power RFI, the SAR imaging quality is severely degraded. Nevertheless, existing studies on RFI mitigation mainly focus on narrowband filtering, while wideband RFI mitigation methods are relatively lacking and perform non-robustly. In this paper, an RFI mitigation scheme is proposed based on instantaneous spectrum forward consecutive mean excision (FCME), which is suitable for both narrowband and wideband RFI mitigation. The SAR echo signal is first transformed into a time–frequency (TF) domain through a short-time Fourier transform (STFT). On this basis, the instantaneous spectra polluted via RFI are detected via a kurtosis-based statistical test and then filtered via FCME to achieve RFI mitigation. Finally, connected component analysis is applied as a safety measure so as to avoid the unnecessary loss of useful target signal. The combination of FCME and connected component analysis enables the proposed method to thoroughly filter out RFI while retaining more useful target signals compared with other competing methods. The experimental results on real SAR raw data validate the effectiveness of the proposed method.
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Bezerra, Bruna Suellen Borges Resende, Mariana Mundim Alves Gomes, Danilo Rodrigues Boaventura, Aline Maria Soares Ferreira, Egleu Diomedes Marinho Mendes, and Carina Ubirajara De Faria. "Phenotypic association between residual feed intake and carcass traits of young nelore bulls." Bioscience Journal 37 (December 29, 2021): e37081. http://dx.doi.org/10.14393/bj-v37n0a2021-48077.
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The purpose of this study was to estimate the phenotypic associations between residual food intake (RFI) and carcass traits, evaluated by ultrasonography, of young Nellore bulls. Information about 53 young Nelore bulls, pure origin (PO), participants in the Individual Performance Test of Nelore Bulls, carried out at the Capim Branco experimental farm of the Federal University of Uberlândia (UFU) were used for this purpose. It was evaluated the characteristics of residual feed intake (RFI), rib eye area (REA), marbling (MAR) and fat thickness (FT). In order to estimate the Spearman and Pearson correlation coefficients, the SAS program was used. Regarding the influence of the RFI classes (low RFI, medium RFI and high RFI) on carcass traits, an out analysis of variance was carried out using the least squares method. It was verified that there was no phenotypic association between RFI and the characteristics of REA and MAR, but the relation between FT and the phenotypic association revealed a medium magnitude. However, when evaluating the RFI classes, it was observed that there were no significant differences of the RFI classes with the carcass traits (REA, FT and MAR). It is recommended that new studies are carried out to verify if the selection for RFI does not result in damages to the finishing of carcass in Nelore cattle.
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Wang, Lei, Tao Wang, Qian Peng, Wei Li, Yin Zhou, and Qiang Hao. "SFGPR RFI Suppression Using Wavelet Packet Selective Algorithm." Advanced Materials Research 433-440 (January 2012): 4409–14. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.4409.
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This paper presents a wavelet packet selective algorithm to suppress the radio frequency interference (RFI) in the step-frequency ground-penetrating radar (SFGPR). Based on the property and the form of RFI in the frequency domain of radar echo, the methods of RFI suppression are studied, and the new algorithm is proposed. Using the new algorithm to suppress the RFI in experimental GPR data, the result of the experimentation shows that the algorithm can effectively suppress the RFI in SFGPR. Finally, the performance of the algorithm is analyzed and evaluated. Compared with the median filter algorithm, the ability of the new algorithm to suppress the RFI is significantly improved.
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Yun, Youngsun, Changdon Kee, Jason Rife, Ming Luo, Sam Pullen, and Per Enge. "Detecting RFI Through Integrity Monitoring at a DGPS Reference Station." Journal of Navigation 59, no. 3 (August 23, 2006): 403–22. http://dx.doi.org/10.1017/s0373463306003882.
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Because GPS is a radio navigation system which has a very low power level, it is vulnerable to RFI. Excessive RFI could cause receiver performance degradation, such as degradation of position accuracy, loss of lock and increased acquisition time. After GPS modernization plans introduce dual-frequency civil signals to mitigate ionospheric errors, RFI will remain as one of the dominant threats for differential GPS navigation systems. Examples of safety-critical civil aviation and military missions threatened by RFI include the Local Area Augmentation System (LAAS) and the Joint Precision Approach and Landing System (JPALS). This paper focuses on RFI mitigation through integrity monitoring for a DGPS system like LAAS or JPALS. The mitigation strategy consists of two parts. First, the paper develops a new RFI detection method, using a raw divergence statistic. Second, the paper investigates strategies for maintaining integrity in the case that RFI is detected.To validate the utility of the divergence-based RFI monitor, this paper takes an experimental approach. The experiments assess the performance of the divergence metric and compare it to existing alternatives for RFI detection, such as metrics for Automatic Gain Control (AGC) and carrier-to-noise ratio (C/N0). Generating a monitoring threshold for these statistics proves challenging, because the threshold depends both on the type of RFI threat (e.g. continuous wave, narrow band, wideband, pulsed) and on environmental conditions, such as temperature. As experiments illustrate, the divergence statistic resolves these limitations, as divergence directly estimates ranging source error, independent of the type of RFI threat or the environmental conditions.
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Deshpande, Avinash A., and B. M. Lewis. "Iridium Satellite Signals: A Case Study in Interference Characterization and Mitigation for Radio Astronomy Observations." Journal of Astronomical Instrumentation 08, no. 01 (March 2019): 1940009. http://dx.doi.org/10.1142/s2251171719400099.
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Several post-detection approaches to the mitigation of radio-frequency interference (RFI) are compared by applying them to the strong RFI from the Iridium satellites. These provide estimates for the desired signal in the presence of RFI, by exploiting distinguishing characteristics of the RFI, such as its polarization, statistics, and periodicity. Our data are dynamic spectra with full Stokes parameters and 1[Formula: see text]ms time resolution. Moreover, since most man-made RFI is strongly polarized, we use the data to compare its unpolarized component with its Stokes I. This approach on its own reduces the RFI intensity by many tens of dBs. A comprehensive approach that also recognizes non-Gaussian statistics, and the time and frequency structure inherent in the RFI, permits exceedingly effective post-detection excision provided full Stokes intensity data are available.
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Silvestre, Antonio M., Ana Carolina J. Pinto, Lidiane S. Miranda, Leandro Aparecido F. Silva, Daniel M. Casali, Katia Lirian R. Souza, Werner F. Schleifer, Jessica G. Cardin, Vanessa Gomes L. Gasparini, and Danilo D. Millen. "PSIX-3 Feedlot performance and rumen morphometrics of Nellore cattle differing in phenotypic residual feed intake." Journal of Animal Science 98, Supplement_4 (November 3, 2020): 421–22. http://dx.doi.org/10.1093/jas/skaa278.734.
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Abstract This study, conducted at São Paulo State University feedlot, Dracena campus, Brazil, had the objective to evaluate the effect of ranking Nellore bulls according to residual feed intake (RFI) on feedlot performance and rumen morphometric variables. Twenty-seven 18-mo-old Nellore bulls (425.5 ± 20.1 kg) were randomly allocated in 27 pens (one animal per pen) and fed for 107 days. The multiple step-up diets program consisted of ad libitum feeding of diets with the concentrate level increasing from 70% to 86% concentrate. At harvest, rumen epithelium samples were collected from cranial for rumen morphometric measurements. The RFI was calculated by the difference between the predicted DMI values [DMI = (0.0544*BW0.75) + (2.9659*ADG)] and observed DMI. Then, Nellore bulls were distributed into RFI groups: High (0.5 SD above the mean; n = 8), Medium (±0.5 SD of the mean; n=9) and Low (0.5 SD below the mean; n = 10). Low-RFI Nellore bulls improved (P = 0.04) G:F when compared to High- and Medium-RFI animals (0.142 vs. 0.125 and 0.130; respectively); however, no significant RFI grouping effect was observed for ADG (P = 0.54), final BW (P = 0.54), HCW (P = 0.27), dressing percentage (P = 0.24), final LM area (P = 0.87), final 12th rib fat (P = 0.82), final P8 fat thickness (P = 0.67) and final marbling (P = 0.82). Regarding rumen morphometrics, High-RFI Nellore bulls had larger (P = 0.09) rumen absorptive surface area than Low- and Medium-RFI animals (43.31 vs. 32.95 and 31.27; respectively), which was associated to the greater (P = 0.01) DMI presented by High-RFI animals (10.2 vs. 9.1 and 9.0 for Medium- and Low-RFI Nellore bulls; respectively). Nevertheless, no significant RFI grouping effect was observed for number of papillae (P = 0.28) or mean papillae area (P = 0.61). Thus, Low-RFI Nellore bulls improved feed efficiency without promoting any positive effects on carcass traits and rumen morphometrics.
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Chen, Y., P. F. Arthur, I. M. Barchia, K. Quinn, P. F. Parnell, and R. M. Herd. "Using gene expression information obtained by quantitative real-time PCR to evaluate Angus bulls divergently selected for feed efficiency." Animal Production Science 52, no. 11 (2012): 1058. http://dx.doi.org/10.1071/an12098.
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Residual feed intake (RFI) is a measure of feed efficiency in beef cattle. Young Angus bulls from lines of cattle divergently selected for RFI were used in a gene expression profiling study of the liver. Quantitative real-time PCR (qPCR) assay was used to quantify the differentially expressed genes and the information was used to examine the relationships between the genes and RFI and to classify the bulls into their respective RFI group. Gene expression of 21 genes in liver biopsies from 22 low RFI and 22 high RFI bulls were measured by qPCR. Gene expressions of 14 of the 21 genes were significantly correlated with RFI. The expression of the genes was used in a principal component analysis from which five components were extracted. The five principal components explained 70% of the variation in the dependency structure. The first component was highly correlated (correlation coefficient of 0.69) with RFI. The genes of the glutathione S-transferase Mu family (GSTM1, GSTM2, GSTM4), protocadherin 19 (PCDH19), ATP-binding cassette transporter C4 (ABCC4) and superoxide dismutase 3 (SOD3) are in the xenobiotic pathway and were the key factors in the first principal component. This highlights the important relationship between this pathway and variation in RFI. The second and third principal components were also correlated with RFI, with correlation coefficients of –0.28 and –0.20, respectively. Two of the four important genes of the second principal component work coordinately in the signalling pathways that inhibit the insulin-stimulated insulin receptor and regulate energy metabolism. This is consistent with the observation that a positive genetic correlation exists between RFI and fatness. The important genes in the third principal component are related to the extracellular matrix activity, with low RFI bulls showing high extracellular matrix activity.
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Richardson, E. C., R. M. Herd, V. H. Oddy, J. M. Thompson, J. A. Archer, and P. F. Arthur. "Body composition and implications for heat production of Angus steer progeny of parents selected for and against residual feed intake." Australian Journal of Experimental Agriculture 41, no. 7 (2001): 1065. http://dx.doi.org/10.1071/ea00095.
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Yearling Angus steer progeny of parents selected for low residual feed intake (RFI; high efficiency) or high RFI (low efficiency) were evaluated for feed intake, growth and differences in body composition. RFI is the difference between actual feed intake and expected feed intake based on an animal’s size and growth over a test period. Individual intakes of a high grain content ration and growth rates were recorded for 140 days and then the steers were slaughtered for measurement of body composition. All internal organs and non-carcass fat depots were removed, weighed and ground for chemical analysis. Carcasses were kept overnight in the chiller and the left half of every carcass physically dissected into retail cuts, and then into total fat, lean and bone. Carcass fat and lean were then combined and ground for chemical analysis. Steers from low RFI parents ate less (P<0.05) than the steers from high RFI parents, for similar rates of growth. Improvement in RFI was accompanied by small changes in body composition towards greater lean and less fat in the progeny of low RFI parents. Correlations of sire estimated breeding values for RFI with end of test whole body chemical protein, chemical fat and a principal component that condensed information on fat and lean body composition at the end of the test, were statistically significant. These confirmed there was a genetic association between body composition and RFI, with fatness being associated with higher RFI (i.e. lower efficiency). However, the correlations were small and suggested that less than 5% of the variation in sire RFI was explained by variation in body composition of their steer progeny. There was no evidence that a difference in the chemical composition of gain over the test explained the greater intake of metabolisable energy (ME) by the high RFI steers. The results suggest that the difference in ME intake following a single generation of divergent selection for RFI was due to metabolic processes rather than to changes in body composition.
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Herd, R. M., P. F. Arthur, C. D. K. Bottema, A. R. Egarr, G. H. Geesink, D. S. Lines, S. Piper, J. P. Siddell, J. M. Thompson, and W. S. Pitchford. "Genetic divergence in residual feed intake affects growth, feed efficiency, carcass and meat quality characteristics of Angus steers in a large commercial feedlot." Animal Production Science 58, no. 1 (2018): 164. http://dx.doi.org/10.1071/an13065.
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Growth, feed intake, feed efficiency, and carcass and meat quality characteristics of 136 Angus steers differing in genetic merit for post-weaning residual feed intake (RFIp) were measured over 251 days in a large commercial feedlot. The steers were evaluated in two groups, low (Low-RFI) and high (High-RFI) genetic RFIp, measured by estimated breeding values for RFIp (RFIp-EBV). The difference in RFIp-EBV between the Low- and High-RFI groups was 1.05 kg/day (–0.44 vs 0.61 kg/day; P < 0.05). The Low- and High-RFI steers were similar (P > 0.05) in age (445 vs 444 days) and weight (435 vs 429 kg) at induction, and at the end of the feeding period (705 vs 691 kg). Average daily gain (ADG) over 251 days had a small negative association with variation in RFIp-EBV (P < 0.05), reflecting a 3.6% greater ADG accompanying a difference of 1 kg/day in RFIp-EBV. Pen feed intake and feed conversion by the Low-RFI group were 10.4 kg/day and 9.3 kg/kg, and for the High-RFI group were 11.1 kg/day and 10.4 kg/kg, but without availability of individual animal feed-intake data it was not possible to test for significant differences. Carcass weight and dressing-percentage was similar for the Low- and High-RFI steers. High-RFI steers had a significantly (P < 0.05) greater depth of subcutaneous rib fat at induction and finished with 5 mm more (P < 0.05) fat at the 10/11th ribs on the carcass than the Low-RFI steers. Cross-sectional area of the eye-muscle and three measures of intramuscular or marbling fat did not differ (P > 0.05) between the Low- and High-RFI steers. Shear force was higher (P < 0.05) in meat samples aged for 1 day from the Low-RFI steers, but there was no difference (P > 0.05) from the High-RFI steers after 7 days of ageing. Compression values for meat samples aged for 1 day did not differ between the RFI groups but were higher in meat samples aged for 7 days from the Low-RFI steers. For these Angus steers, genetic superiority in RFI was associated phenotypically with superior weight gain, decreased rib fat depth, slightly less tender meat, and no compromise in marbling fat or other carcass and meat quality traits.
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Uranga, Ekhi, Álvaro Llorente, Judit González, Antonio de la Fuente, Roger Oliva, Yan Soldo, and Flávio Jorge. "SMOS ESA RFI Monitoring and Information Tool: Lessons Learned." Remote Sensing 14, no. 21 (October 27, 2022): 5387. http://dx.doi.org/10.3390/rs14215387.
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The issue of Radio Frequency Interference (RFI) is a widespread problem in most microwave Earth observation missions, and passive instruments are particularly sensitive to RFI. This is the case for SMOS, Soil Moisture and Ocean Salinity, a satellite of the European Space Agency, which operates in the 1400–1427 MHz band, where all emissions are prohibited. Notwithstanding this regulatory framework, SMOS has been affected by RFI all around the world since the beginning of operations in 2010. In the first years of operations, manual detection processes and reporting of RFI to National Regulatory Authorities were in place in order to mitigate the detected sources. After 12 years, a tool called ERMIT (ESA RFI Monitoring and Information Tool) has been developed at ESAC (European Space Astronomy Center). This tool helps the SMOS RFI team in its spectrum monitoring tasks (e.g., RFI monitoring, logging, and reporting) thus allowing it to counteract RFI pollution more efficiently, providing external users with detailed and user-friendly information on the L-band RFI observed by SMOS. The ERMIT tool is now publicly available. This document aims at describing the needs that lead to the development of ERMIT and at presenting the information made available by it.
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Johnson, Chinju, Carolyn Fitzsimmons, Igor Kovalchuk, John Kastelic, and Jacob Thundathil. "Testis-specific changes in gene expression of post-pubertal beef bulls divergent for residual feed intake and exposure to different pre-natal diets." Animal Production Science 60, no. 12 (2020): 1491. http://dx.doi.org/10.1071/an19524.
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Context Selection for residual feed intake (RFI) and its impact on male reproductive development has had mixed reviews in the past. Our previous studies demonstrated earlier puberty, larger testes and greater percentage of progressively motile sperm in high-RFI bulls. However, the molecular mechanisms within testes of bulls with varying RFI remain unclear. Aims To determine the effect of RFI and pre-natal diet on the expression patterns of testicular genes and use this information to explain differences observed across RFI. Methods The study included 25 purebred-Angus bulls with a genetic background of either high or low RFI and fed either normal or low pre-natal nutrition from 30 to 150 days post conception. After slaughter (17 months), testicular tissue was recovered, and RNA was extracted and sequenced. Key results Of 19218 expressed genes, 17 were differentially expressed for RFI (including PLCD1, INPP4B), with no differences being observed for pre-natal diet or diet × RFI interaction (false discovery rate) < 0.1%). KEGG pathway analysis indicated that differentially expressed genes were associated with inositol phosphate metabolism, and phosphatidylinositol signalling. On the basis of a candidate gene-expression study, IGF1R was upregulated in high-RFI bulls (P < 0.1). Conclusions Increased expression of IGF1R and lowered PLCD1 and INPP4B expression could activate PI3K–Akt signalling responsible for cell growth, proliferation and steroid metabolism in high-RFI bulls. Implications Selecting bulls for feed efficiency might affect molecular networks associated with reproduction and fertility.
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Jorge-Smeding, Ezequiel, Sergio Polakof, Muriel Bonnet, Stephanie Durand, Delphine Centeno, Mélanie Pétéra, Sébastien Taussat, and Gonzalo Cantalapiedra-Hijar. "Untargeted metabolomics confirms the association between plasma branched chain amino acids and residual feed intake in beef heifers." PLOS ONE 17, no. 11 (November 29, 2022): e0277458. http://dx.doi.org/10.1371/journal.pone.0277458.
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This study explored plasma biomarkers and metabolic pathways underlying feed efficiency measured as residual feed intake (RFI) in Charolais heifers. A total of 48 RFI extreme individuals (High-RFI, n = 24; Low-RFI, n = 24) were selected from a population of 142 heifers for classical plasma metabolite and hormone quantification and plasma metabolomic profiling through untargeted LC-MS. Most efficient heifers (Low-RFI) had greater (P = 0.03) plasma concentrations of IGF-1 and tended to have (P = 0.06) a lower back fat depth compared to least efficient heifers. However, no changes were noted (P ≥ 0.10) for plasma concentrations of glucose, insulin, non-esterified fatty acids, β-hydroxybutyrate and urea. The plasma metabolomic dataset comprised 3,457 ions with none significantly differing between RFI classes after false discovery rate correction (FDR > 0.10). Among the 101 ions having a raw P < 0.05 for the RFI effect, 13 were putatively annotated by using internal databases and 6 compounds were further confirmed with standards. Metabolic pathway analysis from these 6 confirmed compounds revealed that the branched chain amino acid metabolism was significantly (FDR < 0.05) impacted by the RFI classes. Our results confirmed for the first time in beef heifers previous findings obtained in male beef cattle and pointing to changes in branched-chain amino acids metabolism along with that of body composition as biological mechanisms related to RFI. Further studies are warranted to ascertain whether there is a cause-and-effect relationship between these mechanisms and RFI.
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EBAID, ELSADIG IDRIS EISSA, CHANDER DATT, VIJAY KUMAR SHARMA, KULDEEP DUDI, and SURINDER SINGH LATHWAL. "Variability in residual feed intake, nutrient utilisation and blood parametersin Murrah buffalo calves fed on total mixed ration." Indian Journal of Animal Sciences 94, no. 1 (January 9, 2024): 55–59. http://dx.doi.org/10.56093/ijans.v94.i1.131939.
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The present study was conducted on 18 female Murrah buffalo calves divided into two treatment groups to determine the residual feed intake, nutrient digestibility and blood metabolite parameters when fed with ration containing wheat (Triticum aestivum) straw, berseem (Trifolium alexandrinum) fodder as roughages and concentrate mixture to meet their requirements. Regular recording of body weight and feed intake was done during 90-day trial period. Residual feed intake (RFI) values were determined for individual animals based on which they were divided into low and high RFI groups. DM intake was lower in low RFI animals than high RFI animals. The blood glucose level and growth hormone level in low and high RFI group was comparable in both groups. Low RFI group had greater concentration of creatinine (1.62 vs. 1.21 mg/dL) as well as IGF-1 (136.70 vs. 120.38 ng/mL) whereas, concentration of total plasma protein level (6.80 vs 7.43 g/dL), albumin (3.46 vs 3.71 g/dl), aspartate aminotransferase (102.20 vs. 122.60 IU/L) and cortisol (3.48 vs. 5.32 ng/mL) were lesser in low RFI group with respect to high RFI group, indicating a positive correlation of RFI with total plasma protein, albumin, aspartate aminotransferase and cortisol and a negative correlation with plasma creatinine and IGF-1 levels in female Murrah buffalo calves. It was concluded that low RFI group of female Murrah buffalo calves showed better performance when fed with total mixed ration.
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Idowu, Modoluwamu, Godstime Taiwo, Taylor Sidney, Emily Treon, Yarahy Leal, Deborah Ologunagba, Francisca Eichie, Andres Pech-Cervantes, and Ibukun M. Ogunade. "Effects of rumen-bypass protein supplement on growth performance, hepatic mitochondrial protein complexes, and hepatic immune gene expression of beef steers with divergent residual feed intake." PLOS ONE 19, no. 7 (July 3, 2024): e0293718. http://dx.doi.org/10.1371/journal.pone.0293718.
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We investigated the impact of a rumen-bypass protein (RBP) supplement on growth performance, plasma and urinary N (UN) concentration, hepatic mitochondrial protein complexes, and hepatic mRNA expression of immune genes of beef steers with negative or positive residual feed intake (RFI) phenotype. Forty crossbred beef steers with an average body weight (BW) of 492 ± 36 kg were subjected to a generalized randomized block design over a 42-day experimental period. This study followed a 2 × 2 factorial arrangement of treatments. The factors evaluated were: 1) RFI classification (low-RFI (-2.12 kg/d) vs. high-RFI (2.02 kg/d), and 2) rumen-bypass protein supplement: RBP supplement (RBP; 227 g/steer/d) vs. control diet (CON; 0 g/d), resulting in four distinct treatments: LRFI-CON (n = 10), LRFI-RBP (n = 10), HRFI-CON (n = 10), and HRFI-RBP (n = 10). The RBP supplement (84% crude protein) is a mixture of hydrolyzed feather meal, porcine blood meal, and DL-methionine hydroxy analogue. The beef steers were stratified by BW, randomly assigned to treatments, and housed in four pens (1 treatment/pen) equipped with two GrowSafe feed bunks each to measure individual dry mater intake (DMI). Body weight was measured every 7 d. Liver tissue samples were collected on d 42 from all the beef steers. These samples were used for mRNA expression analysis of 16 immune-related genes and for evaluating the mitochondrial protein complexes I ‐ V. No significant effects due to RBP supplementation or RFI × RBP interactions (P > 0.05) were observed for average daily gain (ADG) and DMI. However, compared to high-RFI steers, low-RFI steers showed a trend towards reduced DMI (12.9 vs. 13.6 kg/d; P = 0.07) but ADG was similar for the two RFI groups. Regardless of RFI status, supplemental RBP increased blood urea nitrogen (BUN) (P = 0.01), with a lower BUN concentration in low-RFI steers compared to high-RFI ones. A tendency for interaction (P = 0.07) between RFI and RBP was detected for the UN concentrations; feeding the dietary RBP increased the UN concentration in high-RFI beef steers (209 vs. 124 mM), whereas the concentration was lower than that of the CON group for low-RFI beef steers (86 vs. 131 mM). Interactions of RBP and RFI were observed (P ≤ 0.05) for mitochondrial activities of complexes IV, V, and mRNA expressions of some immune genes such as TLR2, TLR3, and IL23A. In conclusion, while RBP supplementation did not alter growth performance, its observed effects on hepatic immune gene expression, mitochondrial protein complexes, BUN, and UN depended on the beef steers’ RFI phenotype. Therefore, the RFI status of beef steers should be considered in future studies evaluating the effects of dietary protein supplements.
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Londono-Mendez, Maria Camila, Sergio David Lasso-Ramirez, Vanesa Ramirez-Sepulveda, Carolyn J. Fitzsimmons, Graham Plastow, Edward bork, John A. Basarab, and Gleise Medeiros da Silva. "506 Residual feed intake and thermotolerance in grazing lactating first-calf beef heifers: Effects on metabolism, performance, rumen temperature, and activity behavior." Journal of Animal Science 102, Supplement_3 (September 1, 2024): 143–44. http://dx.doi.org/10.1093/jas/skae234.171.
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Abstract Beef cattle have been selected for feed efficiency to reduce feeding costs and environmental impact, but there is a knowledge gap regarding residual feed intake (RFI) and thermotolerance in grazing beef females. Therefore, this study evaluated blood parameters, rumen temperature (RT), activity behavior, and performance of grazing lactating first-calf beef heifers with divergent RFI during summer. Crossbred beef heifers [n = 35; 432 ± 8.40 kg of body weight (BW) and 26 ± 1 mo of age] previously tested and classified for RFI as more (n = 17; LOW-RFI = -0.8 ± 0.214) or less efficient (n = 18; HIGH-RFI = 1.5 ± 0.220) were used in a completely randomized design, grazing continuously a single pasture during summer (June to August). An accelerometer-based sensor recorded lying, standing, and step counts, while RT was automatically recorded using a rumen bolus throughout the 64-d experimental period. Body weight and blood samples were collected on d 0, 13, 28, and 64, while body fat deposition was assessed via ultrasonography on 0, 13, 28, and 50 d. Plasma was analyzed for concentrations of blood urea nitrogen (BUN), non-esterified fatty acids (NEFA), free triiodothyronine (fT3), heat shock protein 70 (HSP70), and whole blood used to perform a complete blood cell count. Environmental conditions were assessed by calculating the Climate Comprehensive Index (CCI) using temperature, wind speed, solar radiation, and humidity from a weather station within 1 km of the pasture. The resulting CCI index categorized environmental stress from non-existent to imposing extreme danger risk. An RFI × day interaction was observed for NEFA (P = 0.08), with LOW-RFI showing greater concentrations vs. HIGH-RFI on a period classified as not imposing environmental stress. An effect of day (P < 0.01) was detected for BUN, fT3, and HSP70. An RFI × hour (P = 0.02) interaction was detected for RT, where RT was greater from 1400 h to 0600 h in HIGH-RFI. White blood cell counts (P = 0.04) and mean corpuscular volumes were greater (P = 0.05), while plateletcrit was less (P = 0.01) in LOW-RFI. An RFI × day interaction was found for monocytes and monocytes% (P = 0.04), with greater concentrations 24-h after severe stress in HIGH-RFI. The HIGH-RFI tended to have greater RIB fat at d 50 (P = 0.06) despite no differences in gain or BW between groups (P ≥ 0.26). An interaction between RFI × hour (P < 0.01) showed that HIGH-RFI had a greater number of steps and standing time and less lying time during the hottest hours of the day. In summary, this study revealed that RFI influenced physiological and behavioral reactions to environmental stress, favoring the more feed-efficient first-calf beef heifers.
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Aibinu, Ajibade A., Simon Carter, Valerie Francis, and Paulo Vaz-Serra. "Request for information frequency and their turnaround time in construction projects." Built Environment Project and Asset Management 10, no. 1 (August 26, 2019): 1–15. http://dx.doi.org/10.1108/bepam-10-2018-0130.
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Purpose The purpose of this paper is to study the nature of request for information (RFIs) on construction projects by using data analytics to understand the frequency of RFIs, when they occur on projects, and the relationship between project characteristics and frequency of RFIs and between project characteristics and RFI turnaround time. Design/methodology/approach A data-analytic approach using RStudio and Minitab software on 168 construction project cases in Australia and New Zealand involving 1,032,949 correspondences and 53,042 RFI event records made available by Aconex, one of the world largest cloud-based project management platform. Findings Large and complex projects tend to have significantly larger number of RFI events per day and longer RFI turnaround when compared with smaller and less complex projects. Projects with fewer users per organisation recorded a higher RFI turnaround time when compared with projects with more users per organisation – users mean persons involved in managing the project using the online platform (an index of project complexity). RFIs occur early on less complex projects and occur later on more complex projects. Research limitations/implications Benchmarks of RFI incidences and turnaround time have been developed for various project characteristics and, practitioners can use them to monitor the RFI performance of projects. Organisations need to pay greater attention to staffing levels needed to handle RFIs to reduce RFI turnaround time. Originality/value A data-analytic study of RFI yielded insights for managing RFIs. The findings of previous studies on RFIs are difficult to generalise because they are based on single project case study. The influence of project characteristics on RFI frequency and RFI turnaround time is not yet known.
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Petto, Jefferson, Alice Miranda De Oliveira, Marvyn de Santana Do Sacramento, Pedro Elias Santos Souza, Douglas Gibran Lobo do Espírito Santo Cerqueira, Pedro Henrique Santana Moreira, and Wasly Santana Silva. "A resistência do fluxo inspiratório modifica a intensidade de uma sessão de pilates?" Revista Pesquisa em Fisioterapia 13 (December 8, 2023): e5124. http://dx.doi.org/10.17267/2238-2704rpf.2023.e5124.
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INTRODUÇÃO: As evidências sobre a melhora da capacidade funcional utilizando o Método Pilates não são contundentes. Uma possibilidade de melhorar o efeito de uma sessão de Pilates sobre a capacidade cardiorrespiratória de seus praticantes é utilizar a resistência de fluxo inspiratório (RFI) de forma concomitante. Esse efeito pode ser visualizado através da determinação do limiar glicêmico (LG), técnica utilizada como marcador de intensidade do exercício. OBJETIVO: Testar a hipótese de que a utilização de RFI em uma sessão de pilates antecipa o LG. MÉTODOS: Estudo crossover de corte transversal. Foram avaliados 26 indivíduos de ambos os sexos, sendo 10 do sexo masculino, sadios e com idade entre 20 e 40 anos. Os voluntários foram randomizados para dois protocolos: Protocolo RFI – 11 movimentos do Método Pilates com RFI utilizando 20% da pressão inspiratória máxima; e Protocolo sem RFI (SRFI) – 11 movimentos do Método Pilates sem RFI. Os dois protocolos foram realizados no mesmo dia, sendo um pela manhã e outro à tarde, conforme randomização feita por sorteio aleatório simples. No repouso e ao final de cada movimento coletas de sangue capilar foram realizadas para dosagem da glicemia e construção da curva glicêmica. O LG foi determinado no menor ponto da curva. RESULTADOS: O LG foi antecipado no protocolo que utilizou RFI, ou seja, no protocolo com RFI o LG foi visualizado no sexto exercício, enquanto no protocolo SRFI o LG foi visualizado no nono exercício (p<0,05). CONCLUSÃO: A RFI antecipou o LG, o que sugere que a RFI aumenta a intensidade de uma sessão de pilates. Isso aventa a hipótese de que a RFI pode proporcionar a médio e longo prazo benefícios adicionais aos praticantes do Método Pilates.
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Huntley, Clayton C., William J. Weiss, Anna Gazumyan, Aron Buklan, Boris Feld, William Hu, Thomas R. Jones, et al. "RFI-641, a Potent Respiratory Syncytial Virus Inhibitor." Antimicrobial Agents and Chemotherapy 46, no. 3 (March 2002): 841–47. http://dx.doi.org/10.1128/aac.46.3.841-847.2002.
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ABSTRACT Human respiratory syncytial virus (RSV), a paramyxovirus, is a major cause of acute upper and lower respiratory tract infections in infants, young children, and adults. RFI-641 is a novel anti-RSV agent with potent in vitro and in vivo activity. RFI-641 is active against both RSV type A and B strains. The viral specificity and the large therapeutic window of RFI-641 (>100-fold) indicate that the antiviral activity of the compound is not due to adverse effects on normal cells. The potent in vitro activity of RFI-641 can be translated to efficacy in vivo: RFI-641 is efficacious when administered prophylactically by the intranasal route in mice, cotton rats, and African green monkeys. RFI-641 is also efficacious when administered therapeutically (24 h postinfection) in the monkey model. Mechanism of action studies indicate that RFI-641 blocks viral F protein-mediated fusion and cell syncytium formation.
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Parsons, Cory T., Julia M. Dafoe, Samuel A. Wyffels, Timothy DelCurto, and Darrin L. Boss. "The Influence of Residual Feed Intake and Cow Age on Beef Cattle Performance, Supplement Intake, Resource Use, and Grazing Behavior on Winter Mixed-Grass Rangelands." Animals 11, no. 6 (May 23, 2021): 1518. http://dx.doi.org/10.3390/ani11061518.
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The objectives of this study were to evaluate the influence of RFI and cow age on the supplement intake and grazing behavior of beef cattle. Average daily supplement intake (kg/cow/d) displayed an RFI × cow age interaction (p < 0.01), with a linear increase in average daily supplement intake with increasing RFI of 3-year-old cows (p < 0.01). Average daily supplement intake (g ∙ kg BW−1 ∙ d−1) displayed an RFI × cow age interaction (p < 0.01), with a quadratic effect on supplement intake of 3-year-old cows (p = 0.01). Cow age displayed a quadratic effect on variation of supplement intake (p < 0.01), where 1-year-old cows had a greater CV of supplement intake than all other cow ages (p < 0.01). Distance traveled displayed a cow age × RFI interaction (p = 0.02), where high-RFI 5-year-old cows traveled further per day than low 5-year-old RFI cows. The probability of grazing site selection was influenced by cow age (p ≤ 0.03). In summary, heifer post-weaning RFI had minimal effects on beef cattle performance, grazing behavior, or resource utilization; however, cow age impacted both grazing behavior and resource use.
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Xu, Wei, Weida Xing, Chonghua Fang, Pingping Huang, Weixian Tan, and Zhiqi Gao. "RFI Suppression for SAR Systems Based on Removed Spectrum Iterative Adaptive Approach." Remote Sensing 12, no. 21 (October 27, 2020): 3520. http://dx.doi.org/10.3390/rs12213520.
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A synthetic aperture radar (SAR) system can be seriously contaminated by radio frequency systems because of working in the same microwave frequency bands, which would degrade the SAR image quality and affect the accuracy of image interpretation. In this paper, a novel radio frequency interference (RFI) suppression approach including RFI identification, band-stop filtering and a removed spectrum iterative adaptive approach (RSIAA) is proposed. First, the smoothing process is added before RFI signal detection to improve the RFI detection capacity. Afterwards, the band-stop filtering with a broaden factor is proposed to mitigate the residual RFI, and it ensures the accuracy of the following removed spectrum recovery by the RSIAA. Finally, the removed spectrum components are estimated from available adjacent spectrum data by the RSIAA in turn to obtain the desired range spectra. Compared with the conventional range frequency filtering method for RFI suppression, the capacity of the weak RFI signal detection is improved, and the increased sidelobes due to the discontinuous spectra are well suppressed. Simulation experiments on both simulated SAR raw data, Gaofen-3 and Sentinel-1 SAR raw data validate the proposed RFI suppression approach.