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Leu, Ching-Ho, i Fei-Fei Kao. "Modified balanced circular systematic sampling". Statistics & Probability Letters 76, nr 4 (luty 2006): 373–83. http://dx.doi.org/10.1016/j.spl.2005.08.005.
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Riaz, Saba, Giancarlo Diana i Javid Shabbir. "Modified classes of estimators in circular systematic sampling". Hacettepe Journal of Mathematics and Statistics 45, nr 84 (27.08.2015): 1. http://dx.doi.org/10.15672/hjms.20158412762.
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Khan, Zaheen, i Javid Shabbir. "Modified Systematic Sampling in The Presence of Linear Trend". Hacettepe Journal of Mathematics and Statistics 44, nr 16 (11.10.2014): 1. http://dx.doi.org/10.15672/hjms.2014167467.
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Azeem, Muhammad. "A modified version of diagonal systematic sampling in the presence of linear trend". PLOS ONE 17, nr 3 (31.03.2022): e0265179. http://dx.doi.org/10.1371/journal.pone.0265179.
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Systematic sampling is one of the simplest and popular methods for selecting a random sample from a finite population. The diagonal systematic sampling scheme is a type of systematic sampling design which has gained the attention of researchers during the last two decades. In this paper, a modification to the conventional diagonal systematic sampling design is proposed for use in situations where population units follow a linear trend. It is found that the proposed strategy reduces the variance of the diagonal systematic sampling thus resulting in an efficient sampling design. The mathematical conditions under which the suggested modified diagonal systematic sampling design is more precise than some of the available sampling designs are derived. With the help of a numerical illustration using milk yield data, it is shown that the proposed sampling scheme is more efficient than some of the available sampling schemes.
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Naidoo, L. R., D. North, T. Zewotir i R. Arnab. "Remainder modified systematic sampling in the presence of linear trend". Communications in Statistics - Theory and Methods 47, nr 10 (8.02.2018): 2469–81. http://dx.doi.org/10.1080/03610926.2017.1295076.
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Javaid, Amjad, Muhammad Noor-ul-Amin i Muhammad Hanif. "Modified Ratio Estimator in Systematic Random Sampling Under Non-response". Proceedings of the National Academy of Sciences, India Section A: Physical Sciences 89, nr 4 (31.07.2018): 817–25. http://dx.doi.org/10.1007/s40010-018-0509-3.
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Singh, Housila P., Rajesh Tailor i Narendra Kumar Jatwa. "Modified Ratio and Product Estimators for Population Mean in Systematic Sampling". Journal of Modern Applied Statistical Methods 10, nr 2 (1.11.2011): 424–35. http://dx.doi.org/10.22237/jmasm/1320120180.
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Naidoo, L. R., D. North, T. Zewotir i R. Arnab. "Multiple-start balanced modified systematic sampling in the presence of linear trend". Communications in Statistics - Theory and Methods 45, nr 14 (25.05.2016): 4307–24. http://dx.doi.org/10.1080/03610926.2015.1091080.
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Kim, Hyuk-Joo, i Byoung-Chul Choi. "Efficient Estimation of Population Mean Using Centered Modified Systematic Sampling and Interpolation". Communications for Statistical Applications and Methods 9, nr 1 (1.04.2002): 175–85. http://dx.doi.org/10.5351/ckss.2002.9.1.175.
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Hoogduin, Lucas A., Thomas W. Hall i Jeffrey J. Tsay. "Modified Sieve Sampling: A Method for Single- and Multi-Stage Probability- Proportional-to-Size Sampling". AUDITING: A Journal of Practice & Theory 29, nr 1 (1.05.2010): 125–48. http://dx.doi.org/10.2308/aud.2010.29.1.125.
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SUMMARY: Widely used probability-proportional-to-size (PPS) selection methods are not well adapted to circumstances requiring sample augmentation. Limitations include: (1) an inability to augment selections while maintaining PPS properties, (2) a failure to recognize changes in census stratum membership which result from sample augmentation, and (3) imprecise control over line item sample size. This paper presents a new method of PPS selection, a modified version of sieve sampling which overcomes these limitations. Simulations indicate the new method effectively maintains sampling stratum PPS properties in single- and multi-stage samples, appropriately recognizes changes in census stratum membership which result from sample augmentation, and provides precise control over line item sample sizes. In single-stage applications the method provides reliable control of sampling risk over varied tainting levels and error bunching patterns. Tightness and efficiency measures are comparable to randomized systematic sampling and superior to sieve sampling.
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Bhaskara Rama Sarma, B., V. Vasantha Kumar i S. V. N. L. Lalitha. "Modified estimator for population mean in systematic sampling using known coefficient of variation". Journal of Physics: Conference Series 1000 (kwiecień 2018): 012135. http://dx.doi.org/10.1088/1742-6596/1000/1/012135.
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Mier, Kathryn L., i Susan J. Picquelle. "Estimating abundance of spatially aggregated populations: comparing adaptive sampling with other survey designs". Canadian Journal of Fisheries and Aquatic Sciences 65, nr 2 (1.02.2008): 176–97. http://dx.doi.org/10.1139/f07-138.
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The main goal in estimating population abundance is to maximize its accuracy and precision. This is difficult when the survey area is large and resources are limited. We implemented a feasible adaptive sampling survey applied to an aggregated population in a marine environment and compared its performance with five classical survey designs. Specifically, larval walleye pollock (Theragra chalcogramma) in the Gulf of Alaska was used as an example of a widespread aggregated population. The six sampling designs included (i) adaptive cluster, (ii) simple random, (iii) systematic, (iv) systematic cluster, (v) stratified systematic, and (vi) unequal probability. Of the five different adaptive estimators used for the adaptive cluster design, the modified Hansen–Hurwitz performed best overall. Of the six survey designs, the stratified systematic survey provided the best overall estimator, given there was accurate prior information on which to base the strata. If no prior information was available, a systematic survey was best. A systematic survey using a single random starting point with a simple random estimator performed as well as and sometimes better than a systematic cluster survey with two starting points (clusters). The adaptive cluster survey showed no advantages when compared with these two designs and furthermore presented substantial logistical challenges.
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Zhang, Mengchuang, Shasha Xia, Xiaochuan Li, Qin Yao, Yang Xu i Zhiping Yin. "Systematic Reliability-Based Multidisciplinary Optimization by Parallel Adaptive Importance Candidate Region". Aerospace 9, nr 5 (26.04.2022): 240. http://dx.doi.org/10.3390/aerospace9050240.
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Reliability-based design optimization (RBDO) has become a prevalent design for aeronautical and aerospace engineering. The main problem is that it is impractical in complex cases with multi-failure regions, especially in multi-objective optimization. The active learning method can obtain an adaptive size of samples to get a relatively acceptable accuracy. The problem of RBDO using the traditional active learning Kriging (ALK) method is that the design space is generally still and only one training point is selected, which is not reasonable based on the concept of importance sampling and parallel calculation. As a consequence, the accuracy improvement is limited. In this paper, we investigate the method of obtaining an optimal size of design and reliability to assess space in parallel, simultaneously. A strategy of parallel adaptive candidate (PAIC) region with ALK is proposed and a sequential optimization and reliability assessment (SORA) method is modified to efficiently improve the accuracy. Importance sampling is used as a demonstration for the modified SORA with more accuracy. The method is then verified using mathematical cases and a scooping system of an amphibious aircraft.
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Zhang, Mengchuang, Shasha Xia, Xiaochuan Li, Qin Yao, Yang Xu i Zhiping Yin. "Systematic Reliability-Based Multidisciplinary Optimization by Parallel Adaptive Importance Candidate Region". Aerospace 9, nr 5 (26.04.2022): 240. http://dx.doi.org/10.3390/aerospace9050240.
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Reliability-based design optimization (RBDO) has become a prevalent design for aeronautical and aerospace engineering. The main problem is that it is impractical in complex cases with multi-failure regions, especially in multi-objective optimization. The active learning method can obtain an adaptive size of samples to get a relatively acceptable accuracy. The problem of RBDO using the traditional active learning Kriging (ALK) method is that the design space is generally still and only one training point is selected, which is not reasonable based on the concept of importance sampling and parallel calculation. As a consequence, the accuracy improvement is limited. In this paper, we investigate the method of obtaining an optimal size of design and reliability to assess space in parallel, simultaneously. A strategy of parallel adaptive candidate (PAIC) region with ALK is proposed and a sequential optimization and reliability assessment (SORA) method is modified to efficiently improve the accuracy. Importance sampling is used as a demonstration for the modified SORA with more accuracy. The method is then verified using mathematical cases and a scooping system of an amphibious aircraft.
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Zhang, Mengchuang, Shasha Xia, Xiaochuan Li, Qin Yao, Yang Xu i Zhiping Yin. "Systematic Reliability-Based Multidisciplinary Optimization by Parallel Adaptive Importance Candidate Region". Aerospace 9, nr 5 (26.04.2022): 240. http://dx.doi.org/10.3390/aerospace9050240.
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Reliability-based design optimization (RBDO) has become a prevalent design for aeronautical and aerospace engineering. The main problem is that it is impractical in complex cases with multi-failure regions, especially in multi-objective optimization. The active learning method can obtain an adaptive size of samples to get a relatively acceptable accuracy. The problem of RBDO using the traditional active learning Kriging (ALK) method is that the design space is generally still and only one training point is selected, which is not reasonable based on the concept of importance sampling and parallel calculation. As a consequence, the accuracy improvement is limited. In this paper, we investigate the method of obtaining an optimal size of design and reliability to assess space in parallel, simultaneously. A strategy of parallel adaptive candidate (PAIC) region with ALK is proposed and a sequential optimization and reliability assessment (SORA) method is modified to efficiently improve the accuracy. Importance sampling is used as a demonstration for the modified SORA with more accuracy. The method is then verified using mathematical cases and a scooping system of an amphibious aircraft.
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Paviot, Romain, Sylvain de la Torre, Arnaud de Mattia, Cheng Zhao, Julian Bautista, Etienne Burtin, Kyle Dawson i in. "Angular systematics-free cosmological analysis of galaxy clustering in configuration space". Monthly Notices of the Royal Astronomical Society 512, nr 1 (15.03.2022): 1341–56. http://dx.doi.org/10.1093/mnras/stac560.
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ABSTRACT Galaxy redshift surveys are subject to incompleteness and inhomogeneous sampling due to the various constraints inherent to spectroscopic observations. This can introduce systematic errors on the summary statistics of interest, which need to be mitigated in cosmological analysis to achieve high accuracy. Standard practices involve applying weighting schemes based on completeness estimates across the survey footprint, possibly supplemented with additional weighting schemes accounting for density-dependent effects. In this work, we concentrate on pure angular systematics and describe an alternative approach consisting in analysing the galaxy two-point correlation function where angular modes are nulled. By construction, this procedure removes all possible known and unknown sources of angular observational systematics, but also part of the cosmological signal. We use a modified Landy–Szalay estimator for the two-point correlation function that relies on an additional random catalogue where angular positions are randomly drawn from the galaxy catalogue, and provide an analytical model to describe this modified statistic. We test the model by performing an analysis of the full anisotropic clustering in mock catalogues of luminous red and emission-line galaxies at 0.43 < z < 1.1. We find that the model fully accounts for the modified correlation function in redshift space, without introducing new nuisance parameters. The derived cosmological parameters from the analysis of baryon acoustic oscillations and redshift-space distortions display slightly larger statistical uncertainties, mostly for the growth rate of structure parameter fσ8 that exhibits a $50{{\ \rm per\ cent}}$ statistical error increase, but free from angular systematic error.
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Xie, Shuilian, i Ulisses M. Braga-Neto. "On the Bias of Precision Estimation Under Separate Sampling". Cancer Informatics 18 (styczeń 2019): 117693511986082. http://dx.doi.org/10.1177/1176935119860822.
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Observational case-control studies for biomarker discovery in cancer studies often collect data that are sampled separately from the case and control populations. We present an analysis of the bias in the estimation of the precision of classifiers designed on separately sampled data. The analysis consists of both theoretical and numerical results, which show that classifier precision estimates can display strong bias under separating sampling, with the bias magnitude depending on the difference between the true case prevalence in the population and the sample prevalence in the data. We show that this bias is systematic in the sense that it cannot be reduced by increasing sample size. If information about the true case prevalence is available from public health records, then a modified precision estimator that uses the known prevalence displays smaller bias, which can in fact be reduced to zero as sample size increases under regularity conditions on the classification algorithm. The accuracy of the theoretical analysis and the performance of the precision estimators under separate sampling are confirmed by numerical experiments using synthetic and real data from published observational case-control studies. The results with real data confirmed that under separately sampled data, the usual estimator produces larger, ie, more optimistic, precision estimates than the estimator using the true prevalence value.
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Ji, Chao, James D. Englehardt i Cynthia Juyne Beegle-Krause. "Design of Real—Time Sampling Strategies for Submerged Oil Based on Probabilistic Model Predictions". Journal of Marine Science and Engineering 8, nr 12 (3.12.2020): 984. http://dx.doi.org/10.3390/jmse8120984.
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Locating and tracking submerged oil in the mid depths of the ocean is challenging during an oil spill response, due to the deep, wide-spread and long-lasting distributions of submerged oil. Due to the limited area that a ship or AUV can visit, efficient sampling methods are needed to reveal the real distributions of submerged oil. In this paper, several sampling plans are developed for collecting submerged oil samples using different sampling methods combined with forecasts by a submerged oil model, SOSim (Subsurface Oil Simulator). SOSim is a Bayesian probabilistic model that uses real time field oil concentration data as input to locate and forecast the movement of submerged oil. Sampling plans comprise two phases: the first phase for initial field data collection prior to SOSim assessments, and the second phase based on the SOSim assessments. Several environmental sampling techniques including the systematic random, modified station plans as well zig-zag patterns are evaluated for the first phase. The data using the first phase sampling plan are then input to SOSim to produce submerged oil distributions in time. The second phase sampling methods (systematic random combined with the kriging-based sampling method and naive zig-zag sampling method) are applied to design the sampling plans within the submerged oil area predicted by SOSim. The sampled data obtained using the second phase sampling methods are input to SOSim to update the model’s assessments. The performance of the sampling methods is evaluated by comparing SOSim predictions using the sampled data from the proposed sampling methods with simulated submerged oil distributions during the Deepwater Horizon spill by the OSCAR (oil spill contingency and response) oil spill model. The proposed sampling methods, coupled with the use of the SOSim model, are shown to provide an efficient approach to guide oil spill response efforts.
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Rombouts, P., i L. Weyten. "Systematic Design of Double-Sampling<tex>$SigmaDelta$</tex>A/D Converters With a Modified Noise Transfer Function". IEEE Transactions on Circuits and Systems II: Express Briefs 51, nr 12 (grudzień 2004): 675–79. http://dx.doi.org/10.1109/tcsii.2004.838440.
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Italianer, Merel F., Eva F. G. Naninck, Jorine A. Roelants, Gijsbertus T. J. van der Horst, Irwin K. M. Reiss, Johannes B. van Goudoever, Koen F. M. Joosten, Inês Chaves i Marijn J. Vermeulen. "Circadian Variation in Human Milk Composition, a Systematic Review". Nutrients 12, nr 8 (4.08.2020): 2328. http://dx.doi.org/10.3390/nu12082328.
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Background: Breastfeeding is considered the most optimal mode of feeding for neonates and mothers. Human milk changes over the course of lactation in order to perfectly suit the infant’s nutritional and immunological needs. Its composition also varies throughout the day. Circadian fluctuations in some bioactive components are suggested to transfer chronobiological information from mother to child to assist the development of the biological clock. This review aims to give a complete overview of studies examining human milk components found to exhibit circadian variation in their concentration. Methods: We included studies assessing the concentration of a specific human milk component more than once in 24 h. Study characteristics, including gestational age, lactational stage, sampling strategy, analytical method, and outcome were extracted. Methodological quality was graded using a modified Newcastle-Ottawa Scale (NOS). Results: A total of 83 reports assessing the circadian variation in the concentration of 71 human milk components were included. Heterogeneity among studies was high. The methodological quality varied widely. Significant circadian variation is found in tryptophan, fats, triacylglycerol, cholesterol, iron, melatonin, cortisol, and cortisone. This may play a role in the child’s growth and development in terms of the biological clock.
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Collins, Samuel A., Kerry Gove, Woolf Walker i Jane S. A. Lucas. "Nasal nitric oxide screening for primary ciliary dyskinesia: systematic review and meta-analysis". European Respiratory Journal 44, nr 6 (16.10.2014): 1589–99. http://dx.doi.org/10.1183/09031936.00088614.
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Nasal nitric oxide (nNO) concentrations are low in patients with primary ciliary dyskinesia (PCD) providing a noninvasive screening test.We conducted a systematic review of the literature to examine the utility of nNO in screening for PCD, in particular 1) different respiratory manoeuvres during sampling (velum closure, tidal breathing, etc.), 2) accuracy in screening young/uncooperative children, 3) stationary versus portable analysers, and 4) nNO in “atypical” PCD.96 papers were assessed according to modified PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria and 22 were included in this review.Meta-analysis of 11 studies comparing nNO during a velum closure breath hold gave a mean±sd nNO of 19.4±18.6 nL·min-1 in PCD (n = 478) and 265.0±118.9 nL·min-1 in healthy controls (n = 338). Weighted mean difference for PCD versus healthy controls was 231.1 nL·min-1 (95% CI 193.3–268.9; n = 338) and 114.1 nL·min-1 (95% CI 101.5–126.8; n = 415) for PCD versus cystic fibrosis. Five studies of nNO measurement during tidal breathing demonstrated that this is an acceptable manoeuvre in young children where velum closure is not possible, but the discriminatory value was reduced. Four small studies of portable NO analysers suggest these are reliable tools for screening for PCD. However, nNO must be interpreted alongside clinical suspicion. Future studies should focus on standardising sampling techniques and reporting.
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Fortin, Mathieu. "Updating plots to improve the precision of small-area estimates: the example of the Lorraine region, France". Canadian Journal of Forest Research 50, nr 7 (lipiec 2020): 648–58. http://dx.doi.org/10.1139/cjfr-2019-0405.
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The sampling intensity of a national forest inventory is usually low. Forest dynamics models can be used to update plots from past inventory campaigns to enhance the precision of the estimate on smaller areas. By doing this, however, the inference relies not only on the sampling design, but also on the model. In this study, the contribution of model predictions to the variance of enhanced small-area estimates was assessed through a case study. The French national forest inventory provided different annual campaigns for a particular region and department of France. Three past campaigns were updated using a forest dynamics model, and estimates of the standing volumes were obtained through two methods: a modified multiple imputation and the Bayesian method. The update greatly increased the precision of the estimate, and the gain was similar between the two methods. The sampling-related variance represented the largest share of the total variance in all cases. This study suggests that plot updating provides more precise estimates as long as (i) the forest dynamics model exhibits no systematic lack of fit and was fitted to a large data set and (ii) the sampling-related variance clearly outweighs the model-related variance.
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Gorbunov, M. E., K. B. Lauritsen, H. H. Benzon, G. B. Larsen, S. Syndergaard i M. B. Sørensen. "Processing of GRAS/METOP radio occultation data recorded in closed-loop and raw-sampling modes". Atmospheric Measurement Techniques Discussions 4, nr 1 (15.02.2011): 1061–77. http://dx.doi.org/10.5194/amtd-4-1061-2011.
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Abstract. Instrument GRAS (Global Navigation Satellite System Receiver for Atmospheric Sounding) on-board of the Metop-A satellite was activated on 27 October 2006. Currently, Metop-A is a fully operational satellite with GRAS providing from 650–700 measurements per day. We describe our processing of GRAS data based on our OCC software, which was modified to become capable of reading and processing GRAS data. We perform a statistical comparison of bending angles and refractivities derived from GRAS data with those derived from ECMWF analyses. We show that GRAS data have error characteristics close to those of COSMIC data. In the height range 10–30 km, the systematic refractivity difference GRAS-ECMWF is of the order of 0.1–0.2%, and the standard deviation is 0.3–0.6%. In the lower troposphere GRAS refractivity and bending angle indicate a negative bias, which reaches its maximum value in the tropics. In particular, the retrieved refractivity is biased by up to 2.5%. The negative bias pattern is similar to that found in the statistical validation of COSMIC data. This makes it probable that the bias should not be attributed to the instrument design or hardware.
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Gorbunov, M. E., K. B. Lauritsen, H. H. Benzon, G. B. Larsen, S. Syndergaard i M. B. Sørensen. "Processing of GRAS/METOP radio occultation data recorded in closed-loop and raw-sampling modes". Atmospheric Measurement Techniques 4, nr 6 (9.06.2011): 1021–26. http://dx.doi.org/10.5194/amt-4-1021-2011.
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Abstract. Instrument GRAS (Global Navigation Satellite System Receiver for Atmospheric Sounding) on-board of the Metop-A satellite was activated on 27 October 2006. Currently, Metop-A is a fully operational satellite with GRAS providing from 650–700 occultations per day. We describe our processing of GRAS data based on the modification of our OCC software, which was modified to become capable of reading and processing GRAS data. We perform a statistical comparison of bending angles and refractivities derived from GRAS data with those derived from ECMWF analyses. We conclude that GRAS data have error characteristics close to those of COSMIC data. In the height range 10–30 km, the systematic refractivity difference GRAS–ECMWF is of the order of 0.1–0.2 %, and the standard deviation is 0.3–0.6 %. In the lower troposphere GRAS refractivity and bending angle indicate a negative bias, which reaches its maximum value in the tropics. In particular the retrieved refractivity is biased by up to 2.5 %. The negative bias pattern is similar to that found in the statistical validation of COSMIC data. This makes it probable that the bias should not be attributed to the instrument design or hardware.
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IANNILLI, VALENTINA, RAFFAELLA BERERA i VEZIO COTTARELLI. "Description of the first marine interstitial ingolfiellid from Philippines, Ingolfiella alba sp. nov., with some remarks on the systematic of the genus (Amphipoda: Ingolfiellidae)". Zootaxa 1675, nr 1 (9.01.2008): 49. http://dx.doi.org/10.11646/zootaxa.1675.1.3.
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The description of a new Ingolfiella of littoral interstitial water, the first finding among Ingolfiellidea for Philippines is presented. Male and female specimens are investigate and the new species seems close to the species group before included into the marine interstitial Tethydiella group. The new taxon shares a high number of features with I. xarifae Ruffo, 1966, described from Maldive Islands. The new species is characterized for the peculiar oosteogites morphology and for the presence in both sexes of spines and setae variously modified. Finally some data on species ecology and sampling sites are given.
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Álvarez-Guevara, Marisser H., Luvianca G. Gil-Moreno, Julio A. Gómez-Rodríguez i Jorge A. Huete-Pérez. "Overview of genetically modified crops and their relevance for Nicaragua". Encuentro, nr 93 (10.12.2012): 63–77. http://dx.doi.org/10.5377/encuentro.v0i93.911.
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The first transgenic plants were created in Europe about three decades ago. In Nicaragua, however, there is not commercial cultivation of transgenic crops allowed yet, and the only history of transgenic grain imports occurred in 2005, when the introduction of 15 events of GM maize was first authorized. The Law on Prevention of Risks from Living Modified Organisms by Means of Molecular Biotechnology was published in 2010, and more recently, in September 2012, the Law on Conservation and Sustainable Use of Biodiversity came into force. In line with the resulting requirements from these laws, the Ministry of Agriculture and Forestry (MAGFOR) currently works in coordination with the Molecular Biology Center at the University of Central America to ensure that grains imported in the country correspond to events legally authorized. This article begins by presenting an overview of transgenic crops (GMO), their history and their implications for the economy and human health. Next, we describe the current status of GMO in Nicaragua. We conclude that MAGFOR has been successful in fulfilling the law in regards to sampling of imports related to the introduction of GMO grains. It is recommended, however, that for better monitoring of compliance with these laws, it will be necessary to establish a systematic monitoring plan nationwide, aimed at the appropriate screening and detection of transgenic material both in crop seeds as well as in imported grains.
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Matović, Bratislav, Dejan Stojanović, Stefan Stjepanović, Marko Gutalj i Boban Miletić. "A comparison of the accuracy of different types of samples for spatial structure indices determination in beech forests in Serbia". Topola, nr 207 (2021): 21–34. http://dx.doi.org/10.5937/topola2101021m.
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In this paper we compared the accuracy of different samples (minus the sample with the NN1 edge correction and buffer zone, plus sample and modified cluster sample) to determine indices of spatial structure in beech forests in Serbia, which can be used in regular forest inventory. The research was conducted in 11 forest stands of different structure at the territory of Central Serbia. Field data used for the assessment of spatial structure indices were collected across the examined stands on the sample plots of different sizes, using systematic grid, with the square layout of sample plots (100x100 meters). The study was conducted on 242 sample plots. For accuracy comparison of different sample types, five indices were used: Uniform angle index, Mean directional index, Species mingling index, DBH differentiation and DBH dominance indices. One-way ANOVA showed that at the stand level there were no statistically significant differences between mean values of indices obtained by different sample types. However, Simple linear correlations confirmed for most indices that if the spatial structure is to be determined with accuracy at the level of sample plots (in this case, a circular fixed radius plot of 5 acres) it is necessary to use a plus sample during data collection. For species mingling and DBH differentiation indices, Simple linear correlations show that both minus sampling with edge correction buffer zone and modified cluster sampling with somewhat less accuracy can be used to a certain extent. Minus sampling with NN1 edge correction is not practical for use on sample plots of this size in beech forests in Serbia.
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Heneghan, Carl J., Elizabeth A. Spencer, Jon Brassey, Annette Plüddemann, Igho J. Onakpoya, David H. Evans, John M. Conly i Tom Jefferson. "SARS-CoV-2 and the role of airborne transmission: a systematic review". F1000Research 10 (24.03.2021): 232. http://dx.doi.org/10.12688/f1000research.52091.1.
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Background: Airborne transmission is the spread of an infectious agent caused by the dissemination of droplet nuclei (aerosols) that remain infectious when suspended in the air. We carried out a systematic review to identify, appraise and summarise the evidence from studies of the role of airborne transmission of SARS-CoV-2. Methods: We searched LitCovid, MedRxiv, Google Scholar and the WHO Covid-19 database from 1 February to 20 December 2020 and included studies on airborne transmission. Data were dual extracted and we assessed quality using a modified QUADAS 2 risk of bias tool. Results: We included 67 primary studies and 22 reviews on airborne SARS-CoV-2. Of the 67 primary studies, 53 (79%) reported data on RT-PCR air samples, 12 report cycle threshold values and 18 copies per sample volume. All primary studies were observational and of low quality. The research often lacked standard methods, standard sampling sizes and reporting items. We found 36 descriptions of different air samplers deployed. Of the 42 studies conducted in-hospital that reported binary RT-PCR tests, 24 (57%) reported positive results for SARs-CoV-2 (142 positives out of 1,403 samples: average 10.1%, range 0% to 100%). There was no pattern between the type of hospital setting (ICU versus non-ICU) and RT-PCR positivity. Seventeen studies reported potential air transmission in the outdoors or in the community. Seven performed RT-PCR sampling, of which two studies report weak positive RNA samples for 2 or more genes (5 of 125 samples positive: average 4.0%). Ten studies attempted viral culture with no serial passage for viral culture. Conclusion: SARS-CoV-2 RNA is detected intermittently in the air in various settings. Standardized guidelines for conducting and reporting research on airborne transmission are needed. The lack of recoverable viral culture samples of SARS-CoV-2 prevents firm conclusions over airborne transmission.
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Kuan, Jew Win, Anselm Ting Su, Chooi Fun Leong, Motomi Osato i Goro Sashida. "Systematic Review of Normal Subjects Harbouring BCR-ABL1 Fusion Gene". Acta Haematologica 143, nr 2 (9.08.2019): 96–111. http://dx.doi.org/10.1159/000501146.
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The treatment of chronic myeloid leukaemia (CML) requires quantitative polymerase chain reaction (qPCR) to monitor BCR-ABL1 in International Scale (IS). Some normal subjects were found to harbour BCR-ABL1. We performed a systematic review on normal subjects harbouring BCR-ABL1. A literature search was done on July 16, 2017 using EBSCOhost Research Databases interface and Western Pacific Region Index Medicus. Two authors selected the studies, extracted the data, and evaluated the quality of studies using the modified Appraisal Tool for Cross-Sectional Studies independently. The outcomes were prevalence, level of BCR-ABL1IS, proportion, and time of progression to CML. The initial search returned 4,770 studies. Eleven studies, all having used convenient sampling, were included, with total of 1,360 subjects. Ten studies used qualitative PCR and one used qPCR (not IS). The mean prevalence of M-BCR was 5.9, 15.5, and 15.9% in cord blood/newborns/infants (CB/NB/I) (n = 170), children (n = 90), and adults (n = 454), respectively, while m-BCR was 15, 26.9, and 23.1% in CB/NB/I (n = 786), children (n = 67), and adults (n = 208), respectively. No study reported the proportion and time of progression to CML. Nine studies were graded as moderate quality, one study as poor quality, and one study as unacceptable. The result of the studies could neither be inferred to the general normal population nor compared. Follow-up data were scarce.
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Heneghan, Carl J., Elizabeth A. Spencer, Jon Brassey, Annette Plüddemann, Igho J. Onakpoya, David H. Evans, John M. Conly i Tom Jefferson. "SARS-CoV-2 and the role of airborne transmission: a systematic review". F1000Research 10 (6.09.2021): 232. http://dx.doi.org/10.12688/f1000research.52091.2.
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Background: Airborne transmission is the spread of an infectious agent caused by the dissemination of droplet nuclei (aerosols) that remain infectious when suspended in the air. We carried out a systematic review to identify, appraise and summarise the evidence from studies of the role of airborne transmission of SARS-CoV-2. Methods: We searched LitCovid, MedRxiv, Google Scholar and the WHO Covid-19 database from 1 February to 20 December 2020 and included studies on airborne transmission. Data were dual extracted and we assessed quality using a modified QUADAS 2 risk of bias tool. Results: We included 67 primary studies and 22 reviews on airborne SARS-CoV-2. Of the 67 primary studies, 53 (79%) reported data on RT-PCR from air samples, 12 (18%) report cycle threshold values and 18 (127%) copies per sample volume. All primary studies were observational and of low quality. The research often lacked standard methods, standard sampling sizes and reporting items. We found 36 descriptions of different air samplers deployed. Of the 42 studies conducted in-hospital that reported binary RT-PCR tests, 24 (57%) reported positive results for SARs-CoV-2 (142 positives out of 1,403 samples: average 10.1%, range 0% to 100%). There was no pattern between the type of hospital setting (ICU versus non-ICU) and RT-PCR positivity. Seventeen studies reported potential air transmission in the outdoors or in the community, of which seven performed RT-PCR sampling, and two studies reported weak positive RNA samples for 2 or more genes (5 of 125 samples positive: average 4.0%). Ten studies attempted viral culture with no serial passage. Conclusion: SARS-CoV-2 RNA is detected intermittently in the air in various settings. Standardized guidelines for conducting and reporting research on airborne transmission are needed. The lack of recoverable viral culture samples of SARS-CoV-2 prevents firm conclusions from being drawn about airborne transmission.
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Giri, Dhirendra Kumar. "Effectiveness between two tooth brushing methods on removing dental plaque". Journal of Nobel Medical College 7, nr 1 (22.08.2018): 26–29. http://dx.doi.org/10.3126/jonmc.v7i1.20843.
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Background: Biofilm usually is a group of micro-organisms in which bacterial cells adhere to each other. It may form on a living or non-living surfaces within a self-produced matrix of glycocalx. Recently, plaque has been identified as a biofilm, and its structure, microbiology and patho-physiology have been described. The effectiveness between modified bass technique and normal brushing technique has been compared in this study. Material & Methods: Sixty auxiliary workers working in Nobel Medical College and Teaching Hospital were selected using systematic random sampling technique. Plaque accumulation was assessed on the index teeth using Silness and Loe plaque index. Both normal tooth brushing practices and modified Bass technique were asked to perform using a standard tooth brush and fluoridated dentifrices without label was used for all the subjects after the morning breakfast. The difference of the PI scores recorded in different examinations was assessed using ANCOVA test. Results: The mean PI score was found similar for normal brushing and modified bass technique at the base line examination (P<0.05). The modified Bass technique was more effective in removing plaque than normal tooth brushing (P<0.05) Conclusion: Tooth brushing is the most common, easy and effective method of plaque control. At the same time tooth brushing with correct technique reduces plaque effectively and maintains the integrity of tooth and surrounding periodontium. Modified Bass technique plays a vital role in prevention of plaque control, dental caries and periodontal disease. Journal of Nobel Medical College Volume 7, Number 1, Issue 12, January-June 2018, Page: 26-29
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Baldwin, D. G., i W. J. Emery. "A systematized approach to AVHRR image navigation". Annals of Glaciology 17 (1993): 414–20. http://dx.doi.org/10.3189/s0260305500013185.
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Accurate co-location and geo-registration of AVHRR (Advanced Very High Resolution Radiometer) is necessary for most applications involving these data. To obtain the necessary accuracy, most of the current systems available for AVHRR image rectification require corrections to errors arising from several different sources. This paper presents a software package which is able to correct registration errors from all sources using effective roll, pitch, and yaw values determined from ground control point offsets. These effective values are used to establish a baseline registration against which other models are compared. Spacecraft and sampling geometry are revisited in order to systemize and better define the procedure of AVHRR geo-registration. This systematic approach has resulted in a modular software package which has a registration accuracy of 1 satellite pixel, and is easily modified and improved.
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Sharan, A. M., i C. Dhanaraj. "A Task Streamlining Approach for Parallel Processing of the Inverse Dynamic Equations With Friction". Journal of Dynamic Systems, Measurement, and Control 115, nr 3 (1.09.1993): 434–40. http://dx.doi.org/10.1115/1.2899120.
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Real-time computation of the inverse dynamics of the robotic manipulators is required for ensuring robust control. This paper presents a modified Newton-Euler algorithm which makes use of symbolic programming for improved computational efficiency. Also, friction is incorporated in the dynamic model for more accurate prediction of the torques. The algorithm is parallelized using a “Task Streamlining Approach,”—a systematic mapping scheme using layered task graphs to create the list schedule and a simplified bin-packing heuristic algorithm to schedule the computations on a multiprocessor. The resulting computational load is only 12n + 9 flops (n = number of links in the manipulator), indicating a promise for application to precision robot control employing a high sampling rate. The optimal scheduling of tasks is carried out by minimizing the number of layers where tasks are performed sequentially.
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Baldwin, D. G., i W. J. Emery. "A systematized approach to AVHRR image navigation". Annals of Glaciology 17 (1993): 414–20. http://dx.doi.org/10.1017/s0260305500013185.
Pełny tekst źródłaStreszczenie:
Accurate co-location and geo-registration of AVHRR (Advanced Very High Resolution Radiometer) is necessary for most applications involving these data. To obtain the necessary accuracy, most of the current systems available for AVHRR image rectification require corrections to errors arising from several different sources. This paper presents a software package which is able to correct registration errors from all sources using effective roll, pitch, and yaw values determined from ground control point offsets. These effective values are used to establish a baseline registration against which other models are compared. Spacecraft and sampling geometry are revisited in order to systemize and better define the procedure of AVHRR geo-registration. This systematic approach has resulted in a modular software package which has a registration accuracy of 1 satellite pixel, and is easily modified and improved.
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Bagheri, Nikrooz, Hojjat Ahmadi, Seyed Kazem Alavipanah i Mahmoud Omid. "Multispectral remote sensing for site-specific nitrogen fertilizer management". Pesquisa Agropecuária Brasileira 48, nr 10 (październik 2013): 1394–401. http://dx.doi.org/10.1590/s0100-204x2013001000011.
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The objective of this work was to evaluate the use of multispectral remote sensing for site-specific nitrogen fertilizer management. Satellite imagery from the advanced spaceborne thermal emission and reflection radiometer (Aster) was acquired in a 23 ha corn-planted area in Iran. For the collection of field samples, a total of 53 pixels were selected by systematic randomized sampling. The total nitrogen content in corn leaf tissues in these pixels was evaluated. To predict corn canopy nitrogen content, different vegetation indices, such as normalized difference vegetation index (NDVI), soil-adjusted vegetation index (Savi), optimized soil-adjusted vegetation index (Osavi), modified chlorophyll absorption ratio index 2 (MCARI2), and modified triangle vegetation index 2 (MTVI2), were investigated. The supervised classification technique using the spectral angle mapper classifier (SAM) was performed to generate a nitrogen fertilization map. The MTVI2 presented the highest correlation (R²=0.87) and is a good predictor of corn canopy nitrogen content in the V13 stage, at 60 days after cultivating. Aster imagery can be used to predict nitrogen status in corn canopy. Classification results indicate three levels of required nitrogen per pixel: low (0-2.5 kg), medium (2.5-3 kg), and high (3-3.3 kg).
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Minkkinen, P. "Monitoring the lot mean and uncertainty estimates by piecewise local modelling". TOS Forum 2022, nr 11 (27.05.2022): 55. http://dx.doi.org/10.1255/tosf.135.
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Variography is an excellent tool for monitoring the long-range trend of continuous processes. Pierre Gy has presented a method that can be used for estimating the measurement variance of a lot mean as function of sampling frequency for different sampling modes: random, stratified, and systematic sample selections. The method involves the estimation of the intercept (also called the nugget effect) of the variogram at the time point zero, and numerical integration of the variogram. The method can also be used for optimising sampling plans. At the time when variography was developed on-line analysers were not available. Samples were extracted from the process streams and analysed in laboratories. It was important to optimise the sampling plans to control the analytical costs and the reliability of the plans in estimating the estimation error. For a reliable variogram more than thirty to forty samples had to be analysed. Consequently, the results could not be used on-line. Currently process analysers are widely used to monitor continuous processes. Like in variographic estimation of the lot mean this method is based on the theory of stratified sampling. If the lot is divided into N1 strata of equal sizes (or sublots) of which n1 are sampled the variance of the lot mean aL is [EQN] Here s21 is the variance between strata mean values and s22 the within-strata variance, N2 is the size of strata as the potential number of samples and n2 the number of samples taken from the stratum. The great advance of stratified sampling is that only the within-strata variance propagates into the lot average if samples are taken from every stratum. With current process analysers measurements can be taken at short time intervals and that is used in the current method to estimate the process average and its variance continuously. Within a short range (or stratum in this case) a continuous process can be locally modelled with a line. With systematic sampling after a minimum of three measurements a line can be fitted to this range and the mean and variance of the range mean calculated. That is the first stratum. When the process progresses, the calculations are repeated for the new strata and values. It is important that the quality of the final lot can be monitored on-line, especially if lots of certain sizes and demanding quality specifications are produced. The method is tested with different kinds of simulated and real data sets. This method can be easily modified also for 2D and 3D sampling targets.
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Cevallos, Holger, Gabriel Intriago i Douglas Plaza. "Ensemble kalman filter and particle filter-based state estimation on electrical power systems". Journal of Physics: Conference Series 2090, nr 1 (1.11.2021): 012016. http://dx.doi.org/10.1088/1742-6596/2090/1/012016.
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Abstract In this article, a referential study of the sequential importance sampling particle filter with a systematic resampling and the ensemble Kalman filter is provided to estimate the dynamic states of several synchronous machines connected to a modified 14-bus test case, when a balanced three-phase fault is applied at a bus bar near one of the generators. Both are supported by Monte Carlo simulations with practical noise and model uncertainty considerations. Such simulations were carried out in MATLAB by the Power System Toolbox, whereas the evaluation of the Particle Filter and the Ensemble Kalman Filter by script files developed inside the toolbox. The results obtained show that the particle filter has higher accuracy and more robustness to measurement and model noise than the ensemble Kalman filter, which helps support the feasibility of the method for dynamic state estimation applications.
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Singh-Franco, Devada, David R. Mastropietro, Miriam Metzner, Michael D. Dressler, Amneh Fares, Melinda Johnson, Daisy De La Rosa i William R. Wolowich. "Impact of pharmacy-supported interventions on proportion of patients receiving non-indicated acid suppressive therapy upon discharge: A systematic review and meta-analysis". PLOS ONE 15, nr 12 (3.12.2020): e0243134. http://dx.doi.org/10.1371/journal.pone.0243134.
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Objective Conduct a systematic review and meta-analysis to estimate the impact of pharmacy-supported interventions on the proportion of patients discharged from the hospital on inappropriate acid suppressive therapy (AST). Methods To identify studies, the following databases were systematically searched on October 14th, 2018 and repeated on September 12th, 2019: Ovid MEDLINE(R) and In-Process & Other Non-Indexed Citations and Daily, Embase.com, CINAHL, Web of Science, Cochrane CENTRAL (EBSCO), and ClinicalTrials.gov. Eligible studies consisted of adults, intervention and historical/usual care groups, description of active pharmacy-supported intervention, and proportion of patients discharged on inappropriate AST. Qualitative assessments and quantitative analyses were performed. Modified funnel plot analysis assessed heterogeneity. Preferred reporting items of systematic reviews and meta-analyses (PRISMA) methodology was used to evaluate studies in this review. Results Seventeen publications resulting in 16 studies were included in the review. Using random effects model, meta-analysis showed a significant reduction in the odds of being discharged on inappropriate AST from the hospital in the pharmacist-supported intervention arm versus comparator (Odds Ratio 0.33 [95%CI 0.20 to 0.53]), with significant heterogeneity (I2 = 86%). Eleven studies favored pharmacy-supported interventions, four were inconclusive and one favored usual care. Using modified funnel plot analysis, our final evaluation was distilled to 11 studies and revealed a similar outcome (OR 0.36 [95%CI 0.27 to 0.48]), but with less heterogeneity (I2 = 36%). Conclusion This systematic review and meta-analysis showed that pharmacy-supported interventions were associated with a significantly reduced probability of patients discharged on inappropriate AST. However, heterogeneity was high and may affect interpretation of results. Using funnel plot optimization method, three positive and two negative studies were objectively removed from analyses, resulting in a similar effect size, but with less heterogeneity. To improve study quality, future researchers should consider utilizing a pre-post, multi-arm, prospective design with sampling randomization, training of data extractors (preferably two extractors), re-evaluating a small dataset to check for agreement and providing a comprehensive methodology in subsequent publications.
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Radhika, A. G., Sutapa B. Neogi, Preetha GS, Sumant Swain, Jaswinder Kaur i Jagdish Kaur. "Smokeless tobacco use and reproductive outcomes among women: a systematic review". F1000Research 10 (3.05.2022): 1171. http://dx.doi.org/10.12688/f1000research.73944.2.
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Background: Both smoked and smokeless tobacco use have deleterious effects on most major organ systems including the reproductive system. We conducted a systematic review on smokeless tobacco (SLT) use and reproductive outcomes among women. Methods: We searched Pubmed, ProQuest, Cochrane, Wiley and Emerald databases for studies involving smokeless tobacco use in women with any or a combination of three conditions: infertility, menstrual disorders and pelvic inflammatory disease (PID). Eligibility criteria included English language publications from 1st January 1990 - 31st October 2020. CADIMA software used for filtering the studies and modified SIGN checklist for the quality assessment. The findings are reported as per the PRISMA guidelines. The AXIS and ROBIN E tool were used for assessment of risk of bias. Results: In total, three studies addressed our research question. Two studies addressed infertility (prospective cohort: n=501, cross sectional: n=192) of which, the cross-sectional study compared the mean cotinine levels between those with infertility, menstrual disorders and PID. This study also explored the association between SLT and PID. PID was the most common gynecological complaint. Women with PID had significantly higher urinary cotinine levels = 24.95±12.259) ng/ ml (p=0.0144). Mean urinary cotinine in women with menstrual complaints was 19.32±10.29 ng/ml. The other study used population-based sampling of 501 couples who attempted pregnancy (enrolled in the LIFE Study). Results showed that 9% and 2% (n=28) of men used snuff and chewed tobacco respectively. and few of the women used smokeless tobacco. Time to pregnancy was shorter among smokeless tobacco users relative to smokers. Conclusions: Available studies exploring associations between SLT and reproductive outcomes are inconclusive due to limitations in the study methodologies. More studies with robust study designs are required from low- and middle-income countries with high prevalence of SLT use.
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Radhika, A. G., Sutapa B. Neogi, Preetha GS, Sumant Swain, Jaswinder Kaur i Jagdish Kaur. "Smokeless tobacco use and reproductive outcomes among women: a systematic review". F1000Research 10 (18.11.2021): 1171. http://dx.doi.org/10.12688/f1000research.73944.1.
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Background: Both smoked and smokeless tobacco use have deleterious effects on most major organ systems including the reproductive system. We conducted a systematic review on smokeless tobacco (SLT) use and reproductive outcomes among women. Methods: We searched Pubmed, ProQuest, Cochrane, Wiley and Emerald databases for studies involving smokeless tobacco use in women with any or a combination of three conditions: infertility, menstrual disorders and pelvic inflammatory disease (PID). Eligibility criteria included English language publications from 1st January 1990 - 31st October 2020. CADIMA software used for filtering the studies and modified SIGN checklist for the quality assessment. The findings are reported as per the PRISMA guidelines. The AXIS and ROBIN E tool were used for assessment of risk of bias. Results: In total, three studies addressed our research question. Two studies addressed infertility (prospective cohort: n=501, cross sectional: n=192) of which, the cross-sectional study compared the mean cotinine levels between those with infertility, menstrual disorders and PID. This study also explored the association between SLT and PID. PID was the most common gynecological complaint. Women with PID had significantly higher urinary cotinine levels = 24.95±12.259) ng/ ml (p=0.0144). Mean urinary cotinine in women with menstrual complaints was 19.32±10.29 ng/ml. The other study used population-based sampling of 501 couples who attempted pregnancy (enrolled in the LIFE Study). Results showed that only 2% (n=28) of men and none of the women used smokeless tobacco. Compared with never users of tobacco, smoking by females was individually associated with longer time-to-pregnancy; smoking among males remained significant when modeling partners together. Conclusions: Available studies exploring associations between SLT and reproductive outcomes are inconclusive due to limitations in the study methodologies. More studies with robust study designs are required from low- and middle-income countries with high prevalence of SLT use.
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Siahaan, Sarma, Yohanes Bobbie yanter i Siti Latifah. "PENILAIAN DAYA TARIK OBJEK WISATA ALAM AIR TERJUN GURUNG SEPANGIN DI DESA TEKUDAK KECAMATAN KALIS KABUPATEN KAPUAS HULU". Jurnal Belantara 6, nr 2 (14.08.2023): 293–306. http://dx.doi.org/10.29303/jbl.v6i2.920.
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Assessment of the attractiveness of natural attractions is a systematic and balanced process or activity to gather information about everything unique, of high attractive value for tourists who come to a tourist destination area. This research is expected to be included in the local government as a consideration in the framework of the management and development of natural attractions. The purpose of the research is to get the value of the attraction of natural attractions of Gurung Sepangin Waterfall. The research was conducted for approximately 3 weeks effectively in the field. The method used is a survey method with interview techniques and assisted by questionnaires as data collection instruments, sampling is carried out accidental sampling based on criteria that have been determined by researchers. The number of respondents was 30 people. Data processing uses guidelines for analysis of object operations and natural attractions (ADO-OTDWA) directorate general of PHKA in 2003 which has been modified according to the scores that have been determined for each criterion. The results of research on the assessment of natural attraction objects of Gurung Sepangin Waterfall have an area attraction value of 954.18 or entered into the classification category (B) means that it is quite potential to be developed into a natural tourist destination.
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TAN, AH-HWEE, i HUI-SHIN VIVIEN SOON. "CONCEPT HIERARCHY MEMORY MODEL: A NEURAL ARCHITECTURE FOR CONCEPTUAL KNOWLEDGE REPRESENTATION, LEARNING, AND COMMONSENSE REASONING". International Journal of Neural Systems 07, nr 03 (lipiec 1996): 305–19. http://dx.doi.org/10.1142/s0129065796000270.
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This article introduces a neural network based cognitive architecture termed Concept Hierarchy Memory Model (CHMM) for conceptual knowledge representation and commonsense reasoning. CHMM is composed of two subnetworks: a Concept Formation Network (CFN), that acquires concepts based on their sensory representations; and a Concept Hierarchy Network (CHN), that encodes hierarchical relationships between concepts. Based on Adaptive Resonance Associative Map (ARAM), a supervised Adaptive Resonance Theory (ART) model, CHMM provides a systematic treatment for concept formation and organization of a concept hierarchy. Specifically, a concept can be learned by sampling activities across multiple sensory fields. By chunking relations between concepts as cognitive codes, a concept hierarchy can be learned/modified through experience. Also, fuzzy relations between concepts can now be represented in terms of the weights on the links connecting them. Using a unified inferencing mechanism based on code firing, CHMM performs an important class of commonsense reasoning, including concept recognition and property inheritance.
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Heneghan, Carl J., Elizabeth A. Spencer, Jon Brassey, Annette Plüddemann, Igho J. Onakpoya, Jason L. Oke, David H. Evans, John M. Conly i Tom Jefferson. "SARS-CoV-2 and the role of airborne transmission: a systematic review". F1000Research 10 (19.10.2022): 232. http://dx.doi.org/10.12688/f1000research.52091.3.
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Background: Airborne transmission is the spread of an infectious agent caused by the dissemination of droplet nuclei (aerosols) that remain infectious when suspended in the air. We carried out a systematic review to identify, appraise and summarise the evidence from studies of the role of airborne transmission of SARS-CoV-2. Methods: We searched LitCovid, MedRxiv, Google Scholar and the WHO Covid-19 database from 1 February 2020 to 30 May 2022 and included studies on airborne transmission. Data were dual extracted, and we assessed quality using a modified QUADAS 2 risk of bias tool. Results: We included 128 primary studies and 29 reviews on airborne SARS-CoV-2. Of the 128 primary studies, 105 (82%) reported data on RT-PCR from air samples, 28 (22%) report cycle threshold values and 36 (28%) copies per sample volume. All primary studies were observational. The research often lacked standard methods, standard sampling sizes and reporting items. We found 69 descriptions of different air samplers deployed. Of the 80 in-hospital studies that reported binary RT-PCR tests, 362/3079 air samples from 75 studies conducted in hospital ward environments were positive (median 8%, IQR=0 to 23%); 23 studies reported 74/703 RT-PCR positive air samples in the ICU setting (median 17%, IQR=0% to 38%) Thirty-eight studies reported potential air transmission in the outdoors or in the community. Twenty-six studies attempted viral culture, none of which definitively demonstrated that replication-competent SARS-CoV-2 could be recovered in the air. Conclusion: SARS-CoV-2 RNA is detectable intermittently in the air in various settings. Standardized guidelines for conducting and reporting research on airborne transmission are needed. The lack of recoverable viral culture of SARS-CoV-2 from air samples prevents firm conclusions about the definitive role of airborne transmission in SARS-CoV-2.
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Shittu, Abdulhakim Adeoye, Athanasios Kolios i Ali Mehmanparast. "A Systematic Review of Structural Reliability Methods for Deformation and Fatigue Analysis of Offshore Jacket Structures". Metals 11, nr 1 (28.12.2020): 50. http://dx.doi.org/10.3390/met11010050.
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This paper presents the state of the art in Structural Reliability Analysis (SRA) methods with a view of identifying key applications of each method and its proposed variations, qualifying characteristics, advantages, and limitations. Due to the increasing complexity and scale of modern offshore jacket structures, it becomes increasingly necessary to propose an accurate and efficient approach for the assessment of uncertainties in their material properties, geometric dimensions, and operating environments. SRA, as a form of uncertainty analysis, has been demonstrated to be a useful tool in the design of structures because it can directly quantify how uncertainty about input parameters can affect structural performance. Herein, attention was focused specifically on the probabilistic fracture mechanics approach because this accounts accurately for fatigue reliability mostly encountered as being dominant in the design of such structures. The well-established analytical/approximate methods such as the First- and Second-Order Reliability Methods (FORM/SORM) are widely used as they offer a good balance between accuracy and efficiency for realistic problems. They are, however, inaccurate in cases of highly non-linear systems. As a result, they have been modified using methods such as conjugate search direction approach, saddle point approximation, subset simulation, evidence theory, etc. in order to improve accuracy. Initially, direct simulations methods such as the Monte Carlo Simulation Method (MCS) with its various variance reduction techniques such as the Importance Sampling (IS), Latin Hypercube Sampling (LHS), etc. are ideal for structures having non-linear limit states but perform poorly for problems that calculate very low probabilities of failure. Overall, each method has its own merits and limitation, with FORM/SORM being the most commonly used, but recently, simulation methods have increasingly been used due to continuous advances in computation powers. Other relevant methods include the Response Surface Methods (RSM) and the Surrogate Models/Meta-models (SM/MM), which are advanced approximation methods and are ideal for structures with implicit limit state functions and high-reliability indices. Combinations of advanced approximation methods and reliability analysis methods are also found in literature as they can be suitable for complex, highly non-linear problems.
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Gulev, Sergey K., i Konstantin Belyaev. "Probability Distribution Characteristics for Surface Air–Sea Turbulent Heat Fluxes over the Global Ocean". Journal of Climate 25, nr 1 (1.01.2012): 184–206. http://dx.doi.org/10.1175/2011jcli4211.1.
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Abstract To analyze the probability density distributions of surface turbulent heat fluxes, the authors apply the two-parametric modified Fisher–Tippett (MFT) distribution to the sensible and latent turbulent heat fluxes recomputed from 6-hourly NCEP–NCAR reanalysis state variables for the period from 1948 to 2008. They derived the mean climatology and seasonal cycle of the location and scale parameters of the MFT distribution. Analysis of the parameters of probability distributions identified the areas where similar surface turbulent fluxes are determined by the very different shape of probability density functions. Estimated extreme turbulent heat fluxes amount to 1500–2000 W m−2 (for the 99th percentile) and can exceed 2000 W m−2 for higher percentiles in the subpolar latitudes and western boundary current regions. Analysis of linear trends and interannual variability in the mean and extreme fluxes shows that the strongest trends in extreme fluxes (more than 15 W m−2 decade−1) in the western boundary current regions are associated with the changes in the shape of distribution. In many regions changes in extreme fluxes may be different from those for the mean fluxes at interannual and decadal time scales. The correlation between interannual variability of the mean and extreme fluxes is relatively low in the tropics, the Southern Ocean, and the Kuroshio Extension region. Analysis of probability distributions in turbulent fluxes has also been used in assessing the impact of sampling errors in the Voluntary Observing Ship (VOS)-based surface flux climatologies, allowed for the estimation of the impact of sampling in extreme fluxes. Although sampling does not have a visible systematic effect on mean fluxes, sampling uncertainties result in the underestimation of extreme flux values exceeding 100 W m−2 in poorly sampled regions.
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Antido, Jhon Wilson A., i Fresthel Monica M. Climacosa. "Enhanced Isolation of Streptomyces from Different Soil Habitats in Calamba City, Laguna, Philippines using a Modified Integrated Approach". International Journal of Microbiology 2022 (26.10.2022): 1–7. http://dx.doi.org/10.1155/2022/2598963.
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Streptomyces species are considered to be the most prolific sources of various bioactive secondary metabolites that are important for antibiotic production. Here, we describe a modified integrated approach to isolate Streptomyces species from diverse soil habitats, such as dumpsite, garden, forest, grassland, and riverside in Calamba City, Laguna, Philippines. A total of 25 soil samples were collected from a depth of 0–20 cm using systematic random soil sampling. All soil samples were air-dried, crushed, pretreated with calcium carbonate, and incubated on a rotary shaker. Isolation of Streptomyces in soil samples was then performed using the standard serial dilution plate technique on starch casein agar supplemented with nystatin (50 μg/ml) and ampicillin (5 μg/ml). Identification of the Streptomyces isolates was done using a polyphasic method that includes morphological and biochemical characterization. A total of 103 morphologically and biochemically distinct Streptomyces were isolated from diverse soil habitats. The number of Streptomyces isolates varied in each collection site, with the highest number collected from dumpsite soil and the least from forest soil. Most of the hydrogen sulfide producers were noted to be isolated from dumpsite samples. Moreover, more Streptomyces were isolated in soil habitats at higher altitudes with a slightly acidic to alkaline pH and a temperature ranging from 29 to 33°C. Employing the modified integrated approach, we have isolated up to 10 times more Streptomyces compared to early studies. These Streptomyces isolates can be valuable for future drug discovery and development research.
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Wang, Wenting, Wenzhao Zhou, Sheng Wang, Jinyu Huang, Yanna Le, Shijiao Nie, Weijue Wang i Qing Guo. "Accuracy of breath test for diabetes mellitus diagnosis: a systematic review and meta-analysis". BMJ Open Diabetes Research & Care 9, nr 1 (maj 2021): e002174. http://dx.doi.org/10.1136/bmjdrc-2021-002174.
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The review aimed to investigate the accuracy of breath tests in the diagnosis of diabetes mellitus, identify exhaled volatile organic compounds with the most evidence as potential biomarkers, and summarize prospects and challenges in diabetic breath tests. Databases including Medline, PubMed, EMBASE, Cochrane Library and Science Citation Index Expanded were searched. Human studies describing diabetic breath analysis with more than 10 subjects as controls and patients were included. Population demographics, breath test conditions, biomarkers, analytical techniques and diagnostic accuracy were extracted. Quality assessment was performed with the Standards for Reporting Diagnostic Accuracy and a modified QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2). Forty-four research with 2699 patients with diabetes were included for qualitative data analysis and 14 eligible studies were used for meta-analysis. Pooled analysis of type 2 diabetes breath test exhibited sensitivity of 91.8% (95% CI 83.6% to 96.1%), specificity of 92.1% (95% CI 88.4% to 94.7%) and area under the curve (AUC) of 0.96 (95% CI 0.94 to 0.97). Isotopic carbon dioxide (CO2) showed the best diagnostic accuracy with pooled sensitivity of 0.949 (95% CI 0.870 to 0.981), specificity of 0.946 (95% CI 0.891 to 0.975) and AUC of 0.98 (95% CI 0.97 to 0.99). As the most widely reported biomarker, acetone showed moderate diagnostic accuracy with pooled sensitivity of 0.638 (95% CI 0.511 to 0.748), specificity of 0.801 (95% CI 0.691 to 0.878) and AUC of 0.79 (95% CI 0.75 to 0.82). Our results indicate that breath test is a promising approach with acceptable diagnostic accuracy for diabetes mellitus and isotopic CO2 is the optimal breath biomarker. Even so, further validation and standardization in subject control, breath sampling and analysis are still required.
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Rubenstein, Emma, Carla Maldini, Solange Gonzalez-Chiappe, Sylvie Chevret i Alfred Mahr. "Sensitivity of temporal artery biopsy in the diagnosis of giant cell arteritis: a systematic literature review and meta-analysis". Rheumatology 59, nr 5 (14.09.2019): 1011–20. http://dx.doi.org/10.1093/rheumatology/kez385.
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Abstract Objectives Temporal artery biopsy (TAB) is a reference test for the diagnosis of GCA but reveals inflammatory changes only in a subset of patients. The lack of knowledge of TAB sensitivity hampers comparisons with non-invasive techniques such as temporal artery ultrasonography. We performed a systematic literature review and meta-analysis to estimate the sensitivity of TAB in GCA and to identify factors that may influence the estimate. Methods A systematic literature review involved searching electronic databases and cross-references. Eligibility criteria included publications reporting at least 30 GCA cases fulfilling the original or modified 1990 ACR classification criteria. The pooled proportion of TAB-positive GCA cases was calculated by using aggregated-data meta-analysis with a random-effects model and assessment of heterogeneity with the I2 statistic. Subgroup analyses and meta-regression were used to examine the effect of patient and study characteristics on TAB positivity. Results Among 3820 publications screened, 32 studies (3092 patients) published during 1993–2017 were analysed. The pooled proportion of TAB-positive GCA cases was 77.3% (95% CI: 71.8, 81.9%), with high between-study heterogeneity (I2 = 90%). The proportion of TAB-positive cases was slightly higher in publications before than in 2012 and after (P = 0.001). Conclusion The estimated sensitivity of 77% provides indirect evidence that TAB is not less sensitive than temporal artery imaging. The unexplained high between-study heterogeneity could result from differences in TAB sampling, processing or interpretation. The decrease in TAB-positive GCA cases over time could reflect an increasing propensity for clinicians to accept a GCA diagnosis without proof by TAB.
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Hagen, Briana N. M., Charlotte B. Winder, Jared Wootten, Carrie K. McMullen i Andria Jones-Bitton. "A Systematic Review and Meta-Analysis of Depression among Farming Populations Worldwide". International Journal of Environmental Research and Public Health 17, nr 24 (15.12.2020): 9376. http://dx.doi.org/10.3390/ijerph17249376.
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A systematic review and meta-analysis were conducted to determine the overall prevalence of depression among farming populations globally, and explore any heterogeneity present. Eligible studies were primary research articles published in English, which involved the collection of data for the purpose of determining the prevalence of depression among a farming population. Four relevant databases were searched in January 2019. Potential for bias was assessed using a modified Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. From 7662 records, 72 articles were deemed relevant and had data extracted. Of these, 45 utilized the Center for Epidemiologic Studies—Depression Revised scale (CES-D/DR) to quantify depression, 42 of which were conducted in the United States (U.S.). As a result, meta-analyses were restricted to this geographic location. Substantial heterogeneity was seen in the initial whole-group analysis (I2 = 97%), and while sub-group exploration suggested a significantly higher prevalence of depression among migrant farm workers (26%, 95% CI = 21–31%) than in studies examining a non-migrant farming population (12%, 95% CI = 8–17%), substantial heterogeneity remained (I2 = 96%), indicating that the majority of between study variation was due to factors other than sampling error. Additionally, the majority of studies (81%) in migrant farm worker populations were published since 2010, while only 21% of studies in non-migrant farming populations were published in this timeframe. It is possible with recent efforts to de-stigmatize mental illness, participants in more recent studies may be more likely to self-report depressive symptoms. Hence, while it appears that migrant farmworker populations may have an elevated prevalence of depression, it is also apparent that little research in the U.S. has been done to evaluate depression among non-migrant farming populations in recent years. Perhaps a reporting bias may account for some of the difference between the two populations. A research gap also appears to exist in estimating the prevalence of depression among farming populations outside of the US. Assessment for bias at the study level revealed challenges in reporting of key study design elements, as well as potential for selection bias in the majority of studies.
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Mwani, Livanze, Epari Ejakait i Paul Akumu Ogenga. "Comparative Analysis of Equity in Teachers’ Grade Promotions". Jumuga Journal of Education, Oral Studies, and Human Sciences (JJEOSHS) 6, nr 1 (10.08.2023): 1–9. http://dx.doi.org/10.35544/jjeoshs.v6i1.41.
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Equity in teachers’ grade promotions was targeted through an inevitable paradigm shift in policy from the “scheme of service” approach to a “Career Progression Guideline” approach for trade unions in Kenya. However, the use of both approaches at post-primary level, in the implementation of the 2017-2021 Collective Bargaining Agreement of unions, espoused differences based on years of service of the teachers. The objective of this comparative study was to determine whether the differences were significant. It was guided by the Socialist economics of education theory and a conceptual framework modified from Walton and McKersie’s behavioural theory for labor negotiations. A comparative research design with a sample of 1,452 respondents drawn from a study population of 5,506 gave a response rate of 100 % of questionnaires. Systematic random sampling selected teachers in each union based on the chronological order of their TSC numbers; while purposive sampling selected school principals was utilized to ensure equal representation from all categories as TSC directors and union secretaries were selected through saturated sampling procedure. The study enhanced content validity while internal consistency reliability of instruments established a Cronbach alpha co-efficient of 0.877. In data analysis, pairwise correlation established plausible interactions between years of service, union membership and promotions while logistic regression analysis revealed that KUPPET union was the one reducing the odds of promotion by up to 23.46% by controlling for teacher-level and school-level characteristics. Gini permutation test results (p≥0.05) established lack of statistically significant difference in equity between the two unions; hence, grade promotion was found to be marginally equitable in KUPPET as compared to KNUT union with gini coefficients of 0.0567 and 0.0698 respectively for the period 2017-2021. Consequently, the research article recommends the harmonization of the two approaches into one and the demarcation policy of membership of teachers in post-primary to one union only.