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Herrmann, Felix J., Deli Wang, and Dirk J. (Eric) Verschuur. "Adaptive curvelet-domain primary-multiple separation." GEOPHYSICS 73, no. 3 (2008): A17—A21. http://dx.doi.org/10.1190/1.2904986.
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In many exploration areas, successful separation of primaries and multiples greatly determines the quality of seismic imaging. Despite major advances made by surface-related multiple elimination (SRME), amplitude errors in the predicted multiples remain a problem. When these errors vary for each type of multiple in different ways (as a function of offset, time, and dip), they pose a serious challenge for conventional least-squares matching and for the recently introduced separation by curvelet-domain thresholding. We propose a data-adaptive method that corrects amplitude errors, which vary smoothly as a function of location, scale (frequency band), and angle. With this method, the amplitudes can be corrected by an elementwise curvelet-domain scaling of the predicted multiples. We show that this scaling leads to successful estimation of primaries, despite amplitude, sign, timing, and phase errors in the predicted multiples. Our results on synthetic and real data show distinct improvements over conventional least-squares matching in terms of better suppression of multiple energy and high-frequency clutter and better recovery of estimated primaries.
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Wu, Xiang, and Barry Hung. "High-fidelity Adaptive Curvelet Domain Primary-Multiple Separation." ASEG Extended Abstracts 2013, no. 1 (2013): 1–4. http://dx.doi.org/10.1071/aseg2013ab094.
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Wu, Xiang, and Barry Hung. "Adaptive primary-multiple separation using 3D curvelet transform." ASEG Extended Abstracts 2015, no. 1 (2015): 1–4. http://dx.doi.org/10.1071/aseg2015ab157.
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Herrmann, Felix J., Urs Böniger, and Dirk Jacob (Eric) Verschuur. "Non-linear primary-multiple separation with directional curvelet frames." Geophysical Journal International 170, no. 2 (2007): 781–99. http://dx.doi.org/10.1111/j.1365-246x.2007.03360.x.
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Subarsyah, Subarsyah, and Tumpal Benhard Nainggolan. "ATENUASI WATER-BOTTOM MULTIPLE DENGAN METODE TRANSFORMASI PARABOLIC RADON." JURNAL GEOLOGI KELAUTAN 12, no. 3 (2016): 145. http://dx.doi.org/10.32693/jgk.12.3.2014.254.
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Interferensi water-bottom multipel terhadap reflektor primer menimbulkan efek bersifat destruktif yang menyebabkan penampang seismik menjadi tidak tepat akibat kehadiran reflektor semu. Teknik demultiple perlu diaplikasikan untuk mengatenuasi multipel. Transformasi parabolic radon merupakan teknik atenuasi multipel dengan metode pemisahan dalam domain radon. Multipel sering teridentifikasi pada penampang seismik. Untuk memperbaiki penampang seismik akan dilakukan dengan metode transformasi parabolic radon. Penerapan metode ini mengakibatkan reflektor multipel melemah dan tereduksi setelah dilakukan muting dalam domain radon terhadap zona multipel. Beberapa reflektor primer juga ikut melemah akibat pemisahan dalam domain radon yang kurang optimal, pemisahan akan optimal membutuhkan distribusi offset yang lebar.
 
 Kata kunci: Parabolic radon, multipel, atenuasi
 
 
 Water-bottom mutiple interference often destructively interfere with primary reflection that led to incorrect seismic section due to presence apparent reflector. Demultiple techniques need to be applied to attenuate the multiple. Parabolic Radon transform is demultiple attenuation technique that separate multiple and primary in radon domain. Water-bottom mutiple ussualy appear and easly identified on seismic data, parabolic radon transform applied to improve the seismic section. Application of this method to data showing multiple reflectors weakened and reduced after muting multiple zones in the radon domain. Some of the primary reflector also weakened due to bad separation in radon domain, optimal separation will require a wide distribution of offsets.
 
 Keywords: Parabolic radon, multiple, attenuation
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Schoenberger, Michael, and Louis M. Houston. "Stationarity transformation of multiples to improve the performance of predictive deconvolution." GEOPHYSICS 63, no. 2 (1998): 723–37. http://dx.doi.org/10.1190/1.1444372.
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Predictive deconvolution is a very effective multiple attenuator for zero‐offset data and for nonzero offset data acquired in water depths less than 100 m. However, predictive deconvolution’s efficacy degrades rapidly with offset, a degradation that correlates highly with nonstationarity of the primary‐to‐multiple traveltime separation. For model data, predictive deconvolution’s performance degrades by a factor of two when the multiple period changes by only 5 ms (20% of the seismic wavelet’s dominant period) within the deconvolution gate. For two‐thirds of the model‐data offsets, the change in primary‐multiple separation on each trace exceeds 40% of the dominant period, and deconvolution is completely ineffective at removing multiples. We develop a stationarity transform, which is a moveout operation or a time‐variable time shift that can be applied separately to each trace. The stationarity transform stabilizes the traveltime separation between primary and first‐order multiple, based upon the assumptions of hyperbolic moveout, layer‐cake geology, and Dix multiple velocities. After applying the stationarity transform to a model data set consisting of primaries and first‐order multiples only, predictive deconvolution suppresses multiples at the theoretical suppression limit for all offsets. Furthermore, predictive deconvolution is equally effective for low‐frequency and high‐frequency wavelets. When the data set is made more realistic by including higher‐order multiples, predictive deconvolution’s ability to suppress multiple reflections degrades only slightly with offset. Stationarity transformation also improves predictive deconvolution’s multiple suppression on a real data set. Because the real data set is from a region where the water depth is shallower than 100 m, predictive deconvolution suppresses multiples effectively on the near‐ and middle‐offset traces, even without stationarity transformation. However, on the farthest offsets, stationarity transformation improves the efficacy of predictive deconvolution significantly.
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Liu, Kuang-Hung, and William H. Dragoset. "Blind-source separation of seismic signals based on information maximization." GEOPHYSICS 78, no. 4 (2013): V119—V130. http://dx.doi.org/10.1190/geo2012-0136.1.
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Prediction methods for seismic multiples are never ideal in practice and an adaptive subtraction process is needed to account for mismatches between the predicted and the actual multiples. We are interested in the problem of separating primary and multiple seismic signals based on their statistical properties. We link recent advances in the blind-source separation problem to the multiple removal problem, and present a novel adaptive subtraction method based on an information maximization principle. Compared with previous methods, our proposed method uses higher-order statistics of the data and incorporates the filtering nature of the adaptive subtraction problem into our algorithm formulation. We use simulations to show that our proposed adaptive subtraction method outperforms the popular least-squares adaptive subtraction and the independent component analysis methods quantitatively, as measured by the mean-squared error, and qualitatively, as evaluated by the visual quality of the image reconstruction.
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Burton, Andrew, and Larry Lines. "VSP detection of interbed multiples using inside‐outside corridor stacking." GEOPHYSICS 62, no. 5 (1997): 1628–35. http://dx.doi.org/10.1190/1.1444265.
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One of the most difficult problems in the exploration of Devonian reefs is the separation of primaries and short period interbed multiples. This is especially true in cases where weak primary reflections from porous reefal carbonates can be easily masked by interbed multiples generated from stronger shale/carbonate reflections above the reef. This problem of primary‐multiple separation is difficult since there are small normal moveout differences between the primary and short‐period multiple reflections, thus stacking might not be as effective at suppressing multiples as one would hope. Also, predictive deconvolution may be ineffective if it is difficult to design an accurate prediction distance for the deconvolution filter. The ineffectiveness of stacking and deconvolution in some cases has caused us to look for other alternatives. A recent paper by Lines (1996) advocates the use of shaping deconvolution and inversion methods that use well log information. Since reliable well log data are not always available, we examine a vertical seismic profiling (VSP) corridor stacking method for multiple identification proposed in Hardage (1983, 154–155) which obviates some of the conventional problems and which does not require well log data. A variation of this concept was applied to long‐period multiple attenuation by Hampson and Mewhort (1983).
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Donno, Daniela. "Improving multiple removal using least-squares dip filters and independent component analysis." GEOPHYSICS 76, no. 5 (2011): V91—V104. http://dx.doi.org/10.1190/geo2010-0332.1.
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The suppression of multiple events is a crucial task in seismic data processing, and the adaptive subtraction of the predicted multiples is recognized as one of the main challenges for the success of the surface-related multiple elimination technique. The traditional least-squares matching approach can affect the primary events because the estimated multiples tend to adapt to the primaries under the minimum energy condition. We investigate two filtering techniques for improving the multiple removal results. In the first proposed method, we combine the advantages of the least-squares and pattern dip-based subtraction methods. Doing so, we exploit the separation of primaries and multiples in the dip domain, and then we apply the least-squares adaptive subtraction in each dip band before recomposing the data to obtain the final subtraction result. As a result of the dip decomposition, the primary-multiple interferences are reduced, allowing for a more reliable least-squares filtering. In the second method, we propose to replace the multiple subtraction step by a separation step using independent component analysis (ICA) methods. We employ the ICA method after least-squares adaptive filtering. Because of the non-Gaussian distributions of the involved signals, primaries and multiples can be separated by computing the optimal rotation between these two signals. We apply the ICA method in local 2D time-space windows to better compensate the space and time variant character of the data. Two-dimensional synthetic and field data examples demonstrate that the multiple subtraction results of both methods are indeed improved with respect to the classical least-squares method.
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Muijs, Remco, Johan O. Robertsson, and Klaus Holliger. "Prestack depth migration of primary and surface-related multiple reflections: Part I — Imaging." GEOPHYSICS 72, no. 2 (2007): S59—S69. http://dx.doi.org/10.1190/1.2422796.
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Surface-related multiples (i.e., all seismic waves reflected at the free surface at least once) often severely contaminate seismic recordings. Because conventional imaging techniques require input data that consist of primary reflections only, significant processing effort is commonly dedicated to attenuating multiples prior to migration. On the other hand, surface-related multiples provide additional illumination of the subsurface and, therefore, should not be considered as noise. We present a prestack depth-migration method that allows primary and multiple reflections to be imaged simultaneously. Depth imaging using primary and multiple reflections (DIPMR) involves decomposing the datainto upgoing and downgoing wave constituents, followed by downward extrapolation. Artifacts generated by interference of upgoing and downgoing events not associated with the same subsurface reflection points (crosstalk) are attenuated by using a 2D deconvolution imaging condition. In contrast to existing methods, DIPMR does not require a priori information about the source signature or directivity, because the illuminating source wavefield is extracted directly from the data themselves via the up/down separation. Moreover, there is no need for elimination nor identification of multiples prior to migration. By including surface-related multiples in the imaging procedure, the effective source wavefield is stronger, the spatial aperture is wider, and a higher vertical resolution is enabled through the application of a deconvolution-based imaging condition.
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Song, Sha, Jiachun You, Qing Cao, Bin Chen, and Xiaomeng Cao. "Depth Migration Based on Two-Way Wave Equation to Image OBS Multiples: A Case Study in the South Shetland Margin (Antarctica)." Geofluids 2020 (November 9, 2020): 1–9. http://dx.doi.org/10.1155/2020/8843048.
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With the development of marine seismic exploration, the ocean bottom seismometer (OBS) as a new seismic acquisition technology has been widely concerned. Although multiple waves are frequently viewed as noises, they may carry a wealth of subsurface information and produce a broader illumination than primary waves. To perform multiple wave imaging, we propose to utilize a two-way wave equation depth wavefield extrapolation method which is rarely used in this field. A simple dipping model is imaged by using primary and multiple waves, which proves the superiority of multiple waves in imaging over the primary waves and lays a foundation for practical application. Moreover, the comparison of multiple imaging results by reverse time migration and those by our proposed method demonstrates that our proposed method requires less storage space. In this study, we apply this migration method to actual OBS data collected in the South Shetland margin (Antarctica), where gas hydrates have been well documented. Firstly, the wavefield separation method is adopted to process the OBS data, so as to produce reliable primary and multiples waves; secondly, the ray-tracing method is used to derive the velocity field; and finally, the depth wavefield extrapolation method based on the two-way wave equation is applied to image primary and multiple waves. Migration results show that multiple waves provide a broader illumination and a clearer sediment structure than primary waves, especially for the highly shallow reflections.
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Wang, Deli, Rayan Saab, Özgür Yilmaz, and Felix J. Herrmann. "Bayesian wavefield separation by transform-domain sparsity promotion." GEOPHYSICS 73, no. 5 (2008): A33—A38. http://dx.doi.org/10.1190/1.2952571.
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Successful removal of coherent-noise sources greatly determines seismic imaging quality. Major advances have been made in this direction, e.g., surface-related multiple elimination (SRME) and interferometric ground-roll removal. Still, moderate phase, timing, amplitude errors, and clutter in predicted signal components can be detrimental. Adopting a Bayesian approach, along with assuming approximate curvelet-domain independence of the to-be-separated signal components, we construct an iterative algorithm that takes predictions produced by, for example, SRME as input and separates these components in a robust manner. In addition, the proposed algorithm controls the energy mismatch between separated and predicted components. Such a control, lacking in earlier curvelet-domain formulations, improves results for primary-multiple separation on synthetic and real data.
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Liu, Yike, Xuejian Liu, Are Osen, Yu Shao, Hao Hu, and Yingcai Zheng. "Least-squares reverse time migration using controlled-order multiple reflections." GEOPHYSICS 81, no. 5 (2016): S347—S357. http://dx.doi.org/10.1190/geo2015-0479.1.
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Reverse time migration (RTM) using multiples generates inherent crosstalk artifacts due to the interference among multiples of different orders. We have developed a method to remove such crosstalk. This approach first separates the recorded seismic data into primary reflections and multiples using the surface-related multiples elimination algorithm and then isolates the multiples into different orders. We can take any specified, say the [Formula: see text]th, order of multiples data as the incident wave and the next higher order multiples data, ([Formula: see text])th order, as the corresponding primary reflection data for imaging. We have applied the least-squares migration scheme to these two successive orders of multiples. Our method is denoted as least-squares RTM using controlled-order multiples (LSRTM-CM). Our numerical tests demonstrated that LSRTM-CM can significantly improve imaging quality compared with straightforward seismic imaging using multiples without multiples separation.
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Ikelle, Luc T. "Attenuating primaries and free‐surface multiples of vertical cable (VC) data while preserving receiver ghosts of primaries." GEOPHYSICS 66, no. 3 (2001): 953–63. http://dx.doi.org/10.1190/1.1444985.
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Marine vertical cable (VC) data contain primaries, receiver ghosts, free‐surface multiples, and internal multiples just like towed‐streamer data. However, the imaging of towed‐streamer data is based on primary reflections, while the emerging imaging algorithms of VC data tend to use the receiver ghosts of primary reflections instead of the primaries themselves. I present an algorithm for attenuating primaries, free‐surface multiples, and the receiver ghosts of free‐surface multiples while preserving the receiver ghosts of primaries. My multiple attenuation algorithm of VC data is based on an inverse scattering approach known, which is a predict‐then‐subtract method. It assumes that surface seismic data are available or that they can be computed from VC data after an up/down wavefield separation at the receiver locations (streamer data add to VC data some of the wave paths needed for multiple attenuation). The combination of surface seismic data with VC data allows one to predict free‐surface multiples and receiver ghosts as well as the receiver ghosts of primary reflections. However, if the direct wave arrivals are removed from the VC data, this combination will not predict the receiver ghosts of primary reflections. I use this property to attenuate primaries, free‐surface multiples, and receiver ghosts from VC data, preserving only the receiver ghosts of primaries. This method can be used for multicomponent ocean bottom cable data (i.e., arrays of sea‐floor geophones and hydrophones) without any modification to attenuate primaries, free‐surface multiples, and the receiver ghosts of free‐surface multiples while preserving the receiver ghosts of primaries.
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Young, Matthew, Emily Howe, Teejay O’Rear, Kathleen Berridge, and Peter Moyle. "Food Web Fuel Differs Across Habitats and Seasons of a Tidal Freshwater Estuary." Estuaries and Coasts 44, no. 1 (2020): 286–301. http://dx.doi.org/10.1007/s12237-020-00762-9.
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AbstractEstuarine food webs are fueled by multiple different primary producers. However, identifying the relative importance of each producer to consumers is difficult, particularly for fishes that utilize multiple food sources due to both their mobility and their generally high trophic levels. Previous studies have documented broad spatial differences in the importance of primary producers to fishes within the Upper San Francisco Estuary, California, including separation between pelagic and littoral food webs. In this study, we evaluated the importance of primary producers to adult fishes in three closely spaced subregions that represented disparate habitat types (a tidal wetland channel, a turbid backwater channel, and a deep open-water channel), each a potential outcome of local restoration projects. Using stable isotope analysis coupled with a Bayesian mixing model, we identified significant differences in primary-producer contribution to fishes and invertebrates across habitats and seasons, especially in the relative contribution of submersed aquatic vegetation and phytoplankton. Most fishes utilized multiple primary producers and showed little segregation between pelagic and littoral food webs among habitats. Availability of primary producers differs seasonally and across multiple spatial scales, helping to buffer environmental variability and thus enhancing food web resilience. Ecosystem restoration may improve with emphasis on restoring a wide variety of primary producers to support consumers.
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Reiter, Edmund C., M. Nafi Toksöz, Timothy H. Keho, and G. M. Purdy. "Imaging with deep‐water multiples." GEOPHYSICS 56, no. 7 (1991): 1081–86. http://dx.doi.org/10.1190/1.1443119.
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Acquisition of on‐bottom hydrophone data recording of a near‐surface source provides an opportunity to treat water column multiples as useful signal. A ray‐equation based Kirchhoff depth migration is used to image primary reflections and deep‐water multiples recorded on an Ocean Bottom Hydrophone (OBH). The image of the subbottom sediments is shown to be improved by inclusion of the deep‐water multiple in the imaging process. Field data, jointly acquired by Woods Hole Oceanographic Institute and University of Texas Institute for Geophysics at Austin and consisting of an OBH (2300 m depth) recording a 10 800 cubic inch air gun array, are used to illustrate the feasibility of the technique. Images are obtained from both the primary reflections and from energy that has undergone an additional passage through the water column. Comparison of these images reveals an excellent correlation of reflectors with the predicted polarity reversal observed in the multiple’s image. Synthetic data are used to examine the difficulties in identifying the true path of the water column multiple. For flat‐layered media there are two different multiple paths — one that reflects beneath the source and one that reflects over the receiver — which have identical traveltimes. They do not, however, have the same amplitude, and it can be shown that their amplitudes differ sufficiently to allow a reliable image to be extracted from the energy that reflects over the receiver. As a final step, the image obtained from the multiple is corrected for the π phase shift from the free surface and added to the image from the primary reflection. This approach is limited to areas where water depths allow reliable separation of primary reflections from water column multiples. Application of this technique allows the utilization of coherent deep water multiples and results in both extended lateral coverage and an increased signal‐to‐noise ratio in the final image.
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Stoelzle, Michael, Tobias Schuetz, Markus Weiler, Kerstin Stahl, and Lena M. Tallaksen. "Beyond binary baseflow separation: a delayed-flow index for multiple streamflow contributions." Hydrology and Earth System Sciences 24, no. 2 (2020): 849–67. http://dx.doi.org/10.5194/hess-24-849-2020.
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Abstract. Understanding components of the total streamflow is important to assess the ecological functioning of rivers. Binary or two-component separation of streamflow into a quick and a slow (often referred to as baseflow) component are often based on arbitrary choices of separation parameters and also merge different delayed components into one baseflow component and one baseflow index (BFI). As streamflow generation during dry weather often results from drainage of multiple sources, we propose to extend the BFI by a delayed-flow index (DFI) considering the dynamics of multiple delayed contributions to streamflow. The DFI is based on characteristic delay curves (CDCs) where the identification of breakpoint (BP) estimates helps to avoid rather subjective separation parameters and allows for distinguishing four types of delayed streamflow contributions. The methodology is demonstrated using streamflow records from a set of 60 mesoscale catchments in Germany and Switzerland covering a pronounced elevation gradient of roughly 3000 m. We found that the quickflow signal often diminishes earlier than assumed by two-component BFI analyses and distinguished a variety of additional flow contributions with delays shorter than 60 d. For streamflow contributions with delays longer than 60 d, we show that the method can be used to assess catchments' water sustainability during dry spells. Colwell's predictability (PT), a measure of streamflow periodicity and sustainability, was applied to attribute the identified delay patterns to dynamic catchment storage. The smallest dynamic storages were consistently found for catchments between approx. 800 and 1800 m a.s.l. Above an elevation of 1800 m the DFI suggests that seasonal snowpack provides the primary contribution, whereas below 800 m groundwater resources are most likely the major streamflow contributions. Our analysis also indicates that dynamic storage in high alpine catchments might be large and is overall not smaller than in lowland catchments. We conclude that the DFI can be used to assess the range of sources forming catchments' storages and to judge the long-term sustainability of streamflow.
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Fisk, John D., Susan A. Morehouse, Murray G. Brown, Chris Skedgel, and T. Jock Murray. "Hospital-based Psychiatric Service Utilization and Morbidity in Multiple Sclerosis." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 25, no. 3 (1998): 230–35. http://dx.doi.org/10.1017/s0317167100034065.
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ABSTRACT:Background:Despite the common association of psychiatric morbidity and multiple sclerosis (MS), population-based prevalence estimates of these disorders are limited. Such estimates are of particular importance to those conducting trials of interventions for the treatment of MS. This study examined the prevalence of bipolar disorder, depression, and attempted suicide among hospital service utilizers in Nova Scotia and compared these measures for the MS and non-MS population.Methods:Data regarding diagnosis and utilization were extracted from two linked databases which included all hospital separation records for Nova Scotia over a 3 year period (1992/93-1994/95).Results:The prevalence of bipolar disorder in hospitalized MS patients was 1.97% and depression was 4.27%. These rates were significantly higher than the 0.92% and 2.04%, respectively, for the non-MS hospital utilizers. These diagnoses also accounted for more than half of the primary diagnostic codes for psychiatric service separations by MS patients. The proportion of total hospital utilization which was accounted for by psychiatric services did not differ between MS and non-MS utilizers. While suicide attempts were rare, the estimated frequency of suicide attempts in the total MS population was more than three times that of the general population.Conclusions:Bipolar disorder and depression were twice as prevalent in hospitalized MS patients as in the general population of hospital utilizers while the estimated frequency of suicide attempts was at least three times greater. These results illustrate that psychiatric morbidity and service utilization are important considerations in the care of MS patients.
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Gleeson, C., D. A. Hay, C. J. Johnston, and T. M. Theobald. "“Twins in School” — An Australia-wide Program." Acta geneticae medicae et gemellologiae: twin research 39, no. 2 (1990): 231–44. http://dx.doi.org/10.1017/s0001566000005468.
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AbstractThe multiple birth family is more likely to have a dispute with the education system than with any other service. So many potential areas of conflict exist over the abilities and behaviour of multiples and over such issues as separation or keeping back one twin. One reason for disputes is the lack of good data to adequately reflect the different perspectives of parents and teachers and the differing needs of families: the same solution does not apply to all. To provide the first large-scale data base and building upon an initial survey of 85% of all primary school teachers in South Australia, the LaTrobe Twin Study and AMBA worked with Education Departments to set-up in each state Education Research Teams (ERTs) of parents of multiples who were also teachers. The ERTs were crucial in three phases. 1) Developing and circulating questionnaires and publicising the nationwide survey. 784 families and 1264 teachers of their children completed these questionnaires, many reporting that simply having to address the issues raised in the questionnaire was a valuable learning experience. 2) Exploring the data base. Issues arising included the very different bases on which parents and teachers judged separation desirable, with teachers emphasising the unsubstantiated claim that separation is essential to individual development. Separation became more common over the first three years of schooling but 20-25% of twins separated one year were back together the next. 3) Running regional meetings of parents, teachers and administrators to discuss the results and to pool experiences and plan policies at the local level. A need clearly exists to improve the level of consultation between families and school personnel and to ensure the widespread availability of information which identifies key issues in making decisions for that multiple birth family.
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Davydenko, Mikhail, and D. J. Verschuur. "Including and using internal multiples in closed-loop imaging — Field data examples." GEOPHYSICS 83, no. 4 (2018): R297—R305. http://dx.doi.org/10.1190/geo2017-0533.1.
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Nowadays, it is more widely accepted that multiple reflections should not be considered as noise, but as signal that can provide additional illumination of the subsurface. However, one of the challenges in seismic imaging is including all multiples in the migration process for field data in a reliable manner. Although including surface multiples in imaging has been demonstrated already on field data in recent years, the proper imaging of internal multiples is less established. We have determined successful field data applications on imaging that takes all internal multiples into account. This is done via so-called full-wavefield migration (FWM), an inversion-based method in which, given the migration velocity model, the angle-dependent reflectivity is iteratively estimated by minimizing the misfit between the modeled and the measured data. Its forward model is based on a multidimensional version of the so-called Bremmer series, which allows modeling of transmission effects and any type of multiple scattering in the subsurface and, thereby, is able to minimize the data misfit correctly. An application of FWM on deepwater field data from the Norwegian North Sea validates its capabilities to explain and image internal multiples. Furthermore, it is demonstrated on the same field data that the FWM framework can also be used for data interpolation and primary/multiple separation.
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Churchland, Mark M., Nicholas J. Priebe, and Stephen G. Lisberger. "Comparison of the Spatial Limits on Direction Selectivity in Visual Areas MT and V1." Journal of Neurophysiology 93, no. 3 (2005): 1235–45. http://dx.doi.org/10.1152/jn.00767.2004.
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We recorded responses to apparent motion from directionally selective neurons in primary visual cortex (V1) of anesthetized monkeys and middle temporal area (MT) of awake monkeys. Apparent motion consisted of multiple stationary stimulus flashes presented in sequence, characterized by their temporal separation (Δ t) and spatial separation (Δ x). Stimuli were 8° square patterns of 100% correlated random dots that moved at apparent speeds of 16 or 32°/s. For both V1 and MT, the difference between the response to the preferred and null directions declined with increasing flash separation. For each neuron, we estimated the maximum flash separation for which directionally selective responses were observed. For the range of speeds we used, Δ x provided a better description of the limitation on directional responses than did Δ t. When comparing MT and V1 neurons of similar preferred speed, there was no difference in the maximum Δ x between our samples from the two areas. In both V1 and MT, the great majority of neurons had maximal values of Δ x in the 0.25–1° range. Mean values were almost identical between the two areas. For most neurons, larger flash separations led to both weaker responses to the preferred direction and increased responses to the opposite direction. The former mechanism was slightly more dominant in MT and the latter slightly more dominant in V1. We conclude that V1 and MT neurons lose direction selectivity for similar values of Δ x, supporting the hypothesis that basic direction selectivity in MT is inherited from V1, at least over the range of stimulus speeds represented by both areas.
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Herrmann, Felix J., Deli Wang, Gilles Hennenfent, and Peyman P. Moghaddam. "Curvelet-based seismic data processing: A multiscale and nonlinear approach." GEOPHYSICS 73, no. 1 (2008): A1—A5. http://dx.doi.org/10.1190/1.2799517.
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Mitigating missing data, multiples, and erroneous migration amplitudes are key factors that determine image quality. Curvelets, little “plane waves,” complete with oscillations in one direction and smoothness in the other directions, sparsify a property we leverage explicitly with sparsity promotion. With this principle, we recover seismic data with high fidelity from a small subset (20%) of randomly selected traces. Similarly, sparsity leads to a natural decorrelation and hence to a robust curvelet-domain primary-multiple separation for North Sea data. Finally, sparsity helps to recover migration amplitudes from noisy data. With these examples, we show that exploiting the curvelet's ability to sparsify wavefrontlike features is powerful, and our results are a clear indication of the broad applicability of this transform to exploration seismology.
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Kuffmeier, M., H. Calcutt, and L. E. Kristensen. "The bridge: a transient phenomenon of forming stellar multiples." Astronomy & Astrophysics 628 (August 2019): A112. http://dx.doi.org/10.1051/0004-6361/201935504.
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Context. Observations with modern instruments such as Herschel reveal that stars form clustered inside filamentary arms of ~1 pc length embedded in giant molecular clouds (GMCs). On smaller scales of ~1000 au, observations of IRAS 16293–2422, for example, show signs of filamentary “bridge” structures connecting young protostars to their birth environment. Aims. We aim to find the origin of bridges associated with deeply embedded protostars by characterizing their connection to the filamentary structure present on GMC scales and to the formation of protostellar multiples. Methods. Using the magnetohydrodynamical code RAMSES, we carried out zoom-in simulations of low-mass star formation starting from GMC scales. We analyzed the morphology and dynamics involved in the formation process of a triple system. Results. Colliding flows of gas in the filamentary arms induce the formation of two protostellar companions at distances of ~1000 au from the primary. After their birth, the stellar companions quickly approach, at Δt ~ 10 kyr, and orbit the primary on eccentric orbits with separations of ~100 au. The colliding flows induce transient structures lasting for up to a few 10 kyr that connect two forming protostellar objects that are kinematically quiescent along the line-of-sight. Conclusions. Colliding flows compress gas and trigger the formation of stellar companions via turbulent fragmentation. Our results suggest that protostellar companions initially form with a wide separation of ~1000 au. Smaller separations of a ≲ 100 au are a consequence of subsequent migration and capturing. Associated with the formation phase of the companion, the turbulent environment induces the formation of arc- and bridge-like structures. These bridges can become kinematically quiescent when the velocity components of the colliding flows eliminate each other. However, the gas in bridges still contributes to stellar accretion later. Our results demonstrate that bridge-like structures are a transient phenomenon of stellar multiple formation.
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Shoaa Kazemi, Mehrangiz, Seyyedeh Narjes Omrani, Zahra Mirzaei, and Narges Khatoon Sabuti. "Relationship Between Parenting Myths and Marital Satisfaction in Parents of Primary Schoolers." Journal of Social Sciences Research, SPI 1 (November 15, 2019): 291–96. http://dx.doi.org/10.32861/jssr.spi1.291.296.
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Purpose: Parents’ myths about parenting are among factors affecting couples’ marital satisfaction. The present study aimed to investigate the association of parenting myths with marital satisfaction. Method: Parents of primary school students (3rd–5th grade) in Tehran, Iran, (n = 150) were recruited for the study via convenience sampling. Research tools included Seidi’s Parenting Myths Scale (2016) With 50 questions (α = .94) and ENRICH marital satisfaction scale(1998) with 47 questions . Multiple regression was used for data analysis. Results: significant association was found between parenting myths and marital satisfaction. In the best model, parent-child identity (β = -0.37), excessively calm parenting (β = 0.35), overemphasis on educational achievement (β = 0.28), separation of work and personal life (β = 0.22), and efficacy (β = 0.21) were best predictors of marital satisfaction. Conclusion: parenting myths affect marital satisfaction in different cultural contexts, which illustrates the role of culture and belief in each region on the satisfaction of families in that region.
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Choudhuri, P. Ghosh, and D. D. Knight. "Effects of compressibility, pitch rate, and Reynolds number on unsteady incipient leading-edge boundary layer separation over a pitching airfoil." Journal of Fluid Mechanics 308 (February 10, 1996): 195–217. http://dx.doi.org/10.1017/s0022112096001450.
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The effects of compressibility, pitch rate and Reynolds number on the initial stages of two-dimensional unsteady separation of laminar subsonic flow over a pitching NACA-0012 airfoil have been studied numerically. The approach involves the simulation of the flow by solving the two-dimensional unsteady compressible laminar Navier-Stokes equations employing the implicit approximate-factorization algorithm of Beam & Warming and a boundary-fitted C-grid. The algorithm has been extensively validated through comparison with analytical and previous numerical results. The computations display several important trends for the ‘birth’ of the primary recirculating region which is a principal precursor to leading-edge separation. Increasing the non-dimensional pitch rate from 0.05 to 0.2 at a fixed Reynolds number and Mach number delays the formation of the primary recirculating region. The primary recirculating region also forms closer to the leading edge. Increasing the Mach number from 0.2 to 0.5 at a fixed Reynolds number and pitch rate causes a delay in the formation of the primary recirculating region and also leads to its formation farther from the airfoil top surface. The length scale associated with the recirculating regions increases as well. Increasing the Reynolds number from 104 to 105 at a fixed Mach number and pitch rate hastens the appearance of the primary recirculating region. A shock appears on the top surface at a Reynolds number of 105 along with the simultaneous formation of multiple recirculating regions near the leading edge.
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Shiraz, Parveen, Olivia Francis, Ineavely Delgado, et al. "TSLP-Induced Alterations of Multiple Signaling Pathways in Primary CRLF2 B-ALL Xenografts." Blood 124, no. 21 (2014): 3783. http://dx.doi.org/10.1182/blood.v124.21.3783.3783.
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Abstract B-cell acute lymphoblastic leukemia (B-ALL) with genetic defects leading to overexpression of CRLF2 (CRLF2 B-ALL) is associated with a high relapse rate and poor prognosis. CRLF2 B-ALL comprises approximately half of the high risk B-ALL characterized by a gene expression profile that is similar to that of Philadelphia chromosome-positive ALL (Ph-like B-ALL). In pediatric patients, CRLF B-ALL occurs 5 times more frequently among children of Hispanic and Native American ethnicity and is a major contributor to health disparities in ALL. CRLF2 (cytokine related ligand factor 2) together with the IL-7 receptor alpha chain, forms a receptor complex that is activated by the cytokine, TSLP (Thymic Stromal Lymphopoietin). Activation of CRLF by TSLP leads to downstream JAK-STAT5 and mTOR pathway phosphorylation even in CRLF2 B-ALL harboring activating JAK mutations. We found that primary human marrow (BM) stromal cells express TSLP (RT-PCR and ELISA) and thus provide an in vivo source of TSLP to activate CRLF2 B-ALL cells. Our next step was to develop a xenograft model system to identify the in vivo CRLF2-mediated gene expression profile and disease mechanisms that might contribute to poor prognosis. Unlike most other cytokines, mouse TSLP is species-specific and thus does not activate the human CRLF2 receptor complex. We engineered immune-deficient NOD/SCID IL-2Rγ null (NSG) mice to express normal serum levels (~20 pg/ml) of human TSLP (hTSLP+ mice), as well as control mice that lack human TSLP (hTSLP– mice). Primary human CRLF2 B-ALL were injected into hTSLP+ and hTSLP– mice and expanded for 10 weeks in vivo. Whole genome microarray was performed on CRLF2 B-ALL cells isolated by magnetic separation from the BM of hTSLP+ and hTSLP- xenograft mice. Evaluation of microarray data by Gene Set Enrichment Analysis (GSEA) and Ingenuity Pathway Analysis showed that genes downstream of mTOR pathway activation were upregulated in hTSLP+ as compared to hTSLP- mice, confirming hTSLP activity in the hTSLP+ xenograft mice. Microarray identified 280 genes that are upregulated and 281 genes that are downregulated (> 1.7 fold; p<.05) in vivo in leukemia cells from hTSLP+ as compared to hTSLP– mice. GSEA and Ingenuity Pathway Analysis of these data show increased RAS pathway activation and altered glucose metabolism in CRLF2 B-ALL from hTSLP+ as compared to hTSLP– mice. In addition to increased mTOR pathway activation, these gene expression data implicate altered glucose metabolism and increased RAS pathway activation as potential contributors to the poor prognosis in CRLF2 B-ALL. The hTSLP+ CRLF2 B-ALL xenograft mice described here provide a novel preclinical model for studying disease mechanisms and identifying therapies to target signaling pathways activated by TSLP in CRLF2 B-ALL. Disclosures No relevant conflicts of interest to declare.
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Low, Wan Shi, and Wan Abu Bakar Wan Abas. "Benchtop Technologies for Circulating Tumor Cells Separation Based on Biophysical Properties." BioMed Research International 2015 (2015): 1–22. http://dx.doi.org/10.1155/2015/239362.
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Circulating tumor cells (CTCs) are tumor cells that have detached from primary tumor site and are transported via the circulation system. The importance of CTCs as prognostic biomarker is leveraged when multiple studies found that patient with cutoff of 5 CTCs per 7.5 mL blood has poor survival rate. Despite its clinical relevance, the isolation and characterization of CTCs can be quite challenging due to their large morphological variability and the rare presence of CTCs within the blood. Numerous methods have been employed and discussed in the literature for CTCs separation. In this paper, we will focus on label free CTCs isolation methods, in which the biophysical and biomechanical properties of cells (e.g., size, deformability, and electricity) are exploited for CTCs detection. To assess the present state of various isolation methods, key performance metrics such as capture efficiency, cell viability, and throughput will be reported. Finally, we discuss the challenges and future perspectives of CTC isolation technologies.
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Zheng, Yikang, Yibo Wang, and Xu Chang. "Least-squares data-to-data migration: An approach for migrating free-surface-related multiples." GEOPHYSICS 84, no. 2 (2019): S83—S94. http://dx.doi.org/10.1190/geo2018-0080.1.
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Free-surface-related multiples can provide extra illumination of the subsurface and thus can be usefully included in migration procedures. However, most multiple migration approaches require separation of primaries and free-surface-related multiples or at least prediction of multiples in advance, which is time consuming and prone to errors. The data-to-data migration (DDM) method migrates free-surface-related multiples by forward and backward propagating the recorded full data (containing primaries and free-surface-related multiples). For DDM, there is no need to predict or separate multiples, but the migration results suffer from the crosstalk generated by crosscorrelations of undesired seismic events, e.g., primaries and second-order free-surface-related multiples. We have developed least-squares DDM (LSDDM) for marine data to eliminate the crosstalk generated by DDM. In each iteration, the forward-propagated primaries and free-surface-related multiples are crosscorrelated with the backward-propagated primary and free-surface-related multiple residuals to form the reflectivity gradient. We use a three-layer model and the Marmousi model for numerical tests. The results validate that LSDDM can provide a migrated image with higher signal-to-noise ratio and more balanced amplitudes than DDM. The LSDDM approach might be valuable for general subsurface imaging for marine seismic data when the migration velocity is accurate, and the acquired data have sufficient recording time.
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Tirosh, Amit, Jonathan Keith Killian, David Petersen, et al. "Distinct DNA Methylation Signatures in Neuroendocrine Tumors Specific for Primary Site and Inherited Predisposition." Journal of Clinical Endocrinology & Metabolism 105, no. 10 (2020): 3285–94. http://dx.doi.org/10.1210/clinem/dgaa477.
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Abstract Purpose To compare the deoxyribonucleic acid (DNA) methylation signature of neuroendocrine tumors (NETs) by primary tumor site and inherited predisposition syndromes von Hippel–Lindau disease (VHL) and multiple endocrine neoplasia type 1 (MEN1). Methods Genome-wide DNA methylation (835 424 CpGs) of 96 NET samples. Principal components analysis (PCA) and unsupervised hierarchical clustering analyses were used to determine DNA methylome signatures. Results Hypomethylated CpGs were significantly more common in VHL-related versus sporadic and MEN1-related NETs (P &lt; .001 for both comparisons). Small-intestinal NETs (SINETs) had the most differentially methylated CpGs, either hyper- or hypomethylated, followed by duodenal NETs (DNETs) and pancreatic NETs (PNETs, P &lt; .001 for all comparisons). There was complete separation of SINETs on PCA, and 3 NETs of unknown origin clustered with the SINET samples. Sporadic, VHL-related, and MEN1-related PNETs formed distinct groups on PCA, and VHL clustered separately, showing pronounced DNA hypomethylation, while sporadic and MEN1-related NETs clustered together. MEN1-related PNETs, DNETs, and gastric NETs each had a distinct DNA methylome signature, with complete separation by PCA and unsupervised clustering. Finally, we identified 12 hypermethylated CpGs in the 1A promoter of the APC (adenomatous polyposis coli) gene, with higher methylation levels in MEN1-related NETs versus VHL-related and sporadic NETs (P &lt; .001 for both comparisons). Conclusions DNA CpG methylation profiles are unique in different primary NET types even when occurring in MEN1-related NETs. This tumor DNA methylome signature may be utilized for noninvasive molecular characterization of NETs, through DNA methylation profiling of biopsy samples or even circulating tumor DNA in the near future.
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NOCHY, DOMINIQUE, ERIC DAUGAS, DOMINIQUE DROZ, et al. "The Intrarenal Vascular Lesions Associated with Primary Antiphospholipid Syndrome." Journal of the American Society of Nephrology 10, no. 3 (1999): 507–18. http://dx.doi.org/10.1681/asn.v103507.
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Abstract. Even 10 yr after the identification of the antiphospholipid syndrome (APS), renal involvement in the course of APS is still relatively unrecognized, and is probably underestimated. The association of anticardiolipin antibodies and/or lupus anticoagulant with the development of a vaso-occlusive process involving numerous organs is now confirmed. In a multicenter study, 16 cases of “primary” APS (PAPS) were found and followed for 5 yr or more, all with renal biopsy. In all 16 cases of PAPS, there was a vascular nephropathy characterized by small vessel vaso-occlusive lesions associated with fibrous intimal hyperplasia of interlobular arteries (12 patients), recanalizing thrombi in arteries and arterioles (six patients), and focal cortical atrophy (10 patients). In combination, these led to progressive destruction of the kidney, accelerated by acute glomerular and arteriolar microangiopathy in five patients. Focal cortical atrophy is a distinctive lesion, present in 10 biopsies, and likely represents the histologic and functional renal analogue to the multiple cerebral infarcts detected on imaging studies. The clinical hallmark of this vascular nephropathy in PAPS is systemic hypertension, only variably associated with renal insufficiency, proteinuria, or hematuria. The ensemble of histologic renal lesions defined in this study should aid in the separation of the lesions found in cases of secondary APS, especially systemic lupus erythematosus, into those lesions related to APS and those related to the underlying disease.
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Roy, Chloe, Ryo Tamura, Leigh McDonald, and Hany Gabra. "Successful management of anastomotic leakage with endoscopic fibrin glue injection after primary repair of pure oesophageal atresia." BMJ Case Reports 14, no. 1 (2021): e238823. http://dx.doi.org/10.1136/bcr-2020-238823.
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Anastomotic leakage (AL) occurs in 15% of cases of primary repair of oesophageal atresia. Urgent surgery is indicated in cases of complete anastomotic separation or severe mediastinitis. Otherwise, conservative management including keeping the patient nil per os (NPO), feeding via transanastomotic tube and prolonged parenteral nutrition, has been widely accepted as it can avoid multiple surgeries in neonates and allow oesophageal continuity to be preserved. However, complications relating to prolonged feeding tube use are common downsides to this approach and the negative impact of prolonged NPO on mastication and swallowing function cannot be ignored.In this case report, a novel approach for the treatment of AL with fibrin glue is reported, following primary repair of oesophageal atresia. It was endoscopically injected into the leakage site to enhance healing and early closure. This procedure was safely performed and achieved early establishment of oral feeding.
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Papoulias, Fotis A., and Ibrahim Aydin. "Out-of-Plane Solutions and Bifurcations of Submersibles in Free Positive Buoyancy Ascent." Journal of Ship Research 38, no. 04 (1994): 259–71. http://dx.doi.org/10.5957/jsr.1994.38.4.259.
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The problem of motion stability of submersible vehicles in free positive buoyancy ascent is analyzed. Motion is allowed to occur in combined vertical and horizontal planes. Continuation and catastrophe theory techniques are employed to trace all possible steady-state solutions in six degrees of freedom, while local linearization reveals their stability properties. Vehicle geometric properties and control surface deflections are used as the primary bifurcation parameters. It is shown that multiple solutions may exist in the form of pitchfork bifurcation, solution separation, hysteresis, and teardrop branches. Regions in parameter spaces are identified where extreme sensitivity of solutions to geometric properties and hydrodynamic modeling is present.
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Zhang, Dongliang, and Gerard T. Schuster. "Least-squares reverse time migration of multiples." GEOPHYSICS 79, no. 1 (2014): S11—S21. http://dx.doi.org/10.1190/geo2013-0156.1.
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The theory of least-squares reverse time migration of multiples (RTMM) is presented. In this method, least squares migration (LSM) is used to image free-surface multiples where the recorded traces are used as the time histories of the virtual sources at the hydrophones and the surface-related multiples are the observed data. For a single source, the entire free-surface becomes an extended virtual source where the downgoing free-surface multiples more fully illuminate the subsurface compared to the primaries. Since each recorded trace is treated as the time history of a virtual source, knowledge of the source wavelet is not required and the ringy time series for each source is automatically deconvolved. If the multiples can be perfectly separated from the primaries, numerical tests on synthetic data for the Sigsbee2B and Marmousi2 models show that least-squares reverse time migration of multiples (LSRTMM) can significantly improve the image quality compared to RTMM or standard reverse time migration (RTM) of primaries. However, if there is imperfect separation and the multiples are strongly interfering with the primaries then LSRTMM images show no significant advantage over the primary migration images. In some cases, they can be of worse quality. Applying LSRTMM to Gulf of Mexico data shows higher signal-to-noise imaging of the salt bottom and top compared to standard RTM images. This is likely attributed to the fact that the target body is just below the sea bed so that the deep water multiples do not have strong interference with the primaries. Migrating a sparsely sampled version of the Marmousi2 ocean bottom seismic data shows that LSM of primaries and LSRTMM provides significantly better imaging than standard RTM. A potential liability of LSRTMM is that multiples require several round trips between the reflector and the free surface, so that high frequencies in the multiples suffer greater attenuation compared to the primary reflections. This can lead to lower resolution in the migration image compared to that computed from primaries. Another liability is that the multiple migration image is more down-dip limited than the standard primaries migration image. Finally, if the surface-related multiple elimination method is imperfect and there are strong multiples interfering with the primaries, then the resulting LSRTMM image can be significantly degraded. We conclude that LSRTMM can be a useful complement, not a replacement, for RTM of primary reflections.
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Bernacca, P. L., B. Bucciarelli, M. G. Lattanzi, et al. "Search for Wide Double Stars in the Guide Star Catalog I. All Sky Properties of the Catalog." International Astronomical Union Colloquium 135 (1992): 449–53. http://dx.doi.org/10.1017/s0252921100006941.
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AbstractThe immediate object of this effort is the first systematic investigation of the guide star catalog as a new source list for the discovery of possible new visual binary stars. In this first paper of the series we detail on the way used to establish the properties of the catalog, i.e. techniques adopted to measure its completeness as a function of angular separation, magnitude of the primary, and magnitude differences among the components. We have employed the CCDM catalog as the source list of “certified” visual double and multiple stars. The CCDM stars were first matched (rediscovered) in the Guide Star Catalog and then used to build sufficient statistics to establish the relations among the parameters above. These calibrations are essential to properly correct the two– and three–point angular correlation functions, which are our fundamental tools for establishing lists of new probable visual binary and multiple stars.
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OBABKO, A. V., and K. W. CASSEL. "Navier–Stokes solutions of unsteady separation induced by a vortex." Journal of Fluid Mechanics 465 (August 25, 2002): 99–130. http://dx.doi.org/10.1017/s0022112002008996.
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Numerical solutions of the unsteady Navier–Stokes equations are considered for the flow induced by a thick-core vortex convecting along a surface in a two-dimensional incompressible flow. The presence of the vortex induces an adverse streamwise pressure gradient along the surface that leads to the formation of a secondary recirculation region followed by a narrow eruption of near-wall fluid in solutions of the unsteady boundary-layer equations. The locally thickening boundary layer in the vicinity of the eruption provokes an interaction between the viscous boundary layer and the outer inviscid flow. Numerical solutions of the Navier–Stokes equations show that the interaction occurs on two distinct streamwise length scales depending upon which of three Reynolds-number regimes is being considered. At high Reynolds numbers, the spike leads to a small-scale interaction; at moderate Reynolds numbers, the flow experiences a large-scale interaction followed by the small-scale interaction due to the spike; at low Reynolds numbers, large-scale interaction occurs, but there is no spike or subsequent small-scale interaction. The large-scale interaction is found to play an essential role in determining the overall evolution of unsteady separation in the moderate-Reynolds-number regime; it accelerates the spike formation process and leads to formation of secondary recirculation regions, splitting of the primary recirculation region into multiple corotating eddies and ejections of near-wall vorticity. These eddies later merge prior to being lifted away from the surface and causing detachment of the thick-core vortex.
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Mouri, Mitsuo, and Chiaki Niwa. "Pilot Plant Studies on Filtration of Raw Sewage Using Floating Filter Media and Multiple Filter Column Inlets." Water Science and Technology 28, no. 7 (1993): 143–51. http://dx.doi.org/10.2166/wst.1993.0155.
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The characteristics and performance of solid-liquid separation of raw sewage using floating media and multiple inlets were studied using pilot-scale equipment. Particles over 7 µm, representing approximately 80% of SS and 50% of BOD in raw sewage were efficiently removed. Smaller particles and soluble components, comprising a large part of total BOD, were difficult to remove by filtration. The maximum SS removal ratio (SSRR) and SS quantity removed per unit filter surface (SSR) was achieved using a medium size of 5.5 mm and a filtration rate of 150 µm/d. Inlet switching to a lower position significantly extended the filter run lengths and increased the total SS removed by filtration. Using 5.5 mm filter particles and a 150 m/d filtration rate, 80-89% of SS was removed, 38-42 kg of SS was removed per unit filter sectional area, and filter runs were 55-65 hours. The backwash-filtrate ratio was around 2%. The space requirement of this system will be significantly smaller than the ordinary primary treatment system judging from the trial design of a prototype plant.
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Zhu, Difeng, Li Ping, Yawen Hong, Jiale Shen, Qinjie Weng, and Qiaojun He. "Simultaneous Quantification and Pharmacokinetic Study of Five Homologs of Dalbavancin in Rat Plasma Using UHPLC-MS/MS." Molecules 25, no. 18 (2020): 4100. http://dx.doi.org/10.3390/molecules25184100.
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Dalbavancin is a novel semisynthetic glycopeptide antibiotic that comprises multiple homologs and isomers of similar polarities. However, pharmacokinetic studies have only analyzed the primary components of dalbavancin, namely B0 and B1. In this study, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to simultaneously determinate and investigate the five homologous components of dalbavancin, namely, A0, A1, B0, B1, and B2, in rat plasma. In this method, methanol was used to precipitate plasma, and a triple-bonded alkyl chromatographic column was used for molecule separation, using 0.1% formic acid-acetonitrile as the mobile phase for gradient elution. Targeted homologs were analyzed by a triple quadrupole mass spectrometer using positive electrospray ionization in multiple reaction monitoring mode. The linearity range was 50–2500 ng/mL with a high correlation coefficient (r2 > 0.998). This method was successfully applied in the pharmacokinetic analysis of dalbavancin hydrochloride to investigate dalbavancin components in rats.
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Stump, Brian W., and Robert E. Reinke. "Experimental confirmation of superposition from small-scale explosions." Bulletin of the Seismological Society of America 78, no. 3 (1988): 1059–73. http://dx.doi.org/10.1785/bssa0780031059.
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Abstract An in situ experimental program in alluvium is implemented and analyzed to test linear superposition. After separating stochastic and deterministic propagation path effects, direct superposition is experimentally validated at 20 m for two 5-lb charges spaced as close as 2 m in alluvium. The charges are separated by the scaled range of 147 m/kt1/3 and observed at the scaled range of 1470 m/kt1/3. Finite-spatial source effects are observed and simulated in the plane passing through two charges separated by 2 to 10 m. The deterministic single-burst waveforms are used to model the multiple-burst data. The effects observed and simulated include direct superposition below the corner frequency, shift to lower corner frequency with increasing charge separation, and spectral scalloping. For charges closely spaced (up to 4 m, observed at 20 and 24 m), the primary effect on the waveform is replicated by a constant delay time between two identical waveforms. For charges spaced by 10 m (observed at 20 and 30 m), the effects of propagation path differences must be included. These effects result in smoothed spectra.
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dal Ponte, M., B. Santiago, A. Carnero Rosell, et al. "Increasing the census of ultracool dwarfs in wide binary and multiple systems using Dark Energy Survey DR1 and Gaia DR2 data." Monthly Notices of the Royal Astronomical Society 499, no. 4 (2020): 5302–17. http://dx.doi.org/10.1093/mnras/staa3118.
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ABSTRACT We present the discovery of 255 binary and 6 multiple system candidates with wide (&gt; 5 arcsec) separation composed by ultracool dwarfs (UCDs) companions to stars, plus nine double ultracool dwarf systems. These systems were selected based on common distance criteria. About 90 per cent of the total sample has proper motions available and 73 per cent of the systems also satisfy a common proper motion criterion. The sample of ultracool candidates was taken from the Dark Energy Survey (DES) and the candidate stellar primaries are from Gaia DR2 and DES data. We compute chance alignment probabilities in order to assess the physical nature of each pair. We find that 174 candidate pairs with Gaia DR2 primaries and 81 pairs with a DES star as a primary have chance alignment probabilities $\lt 5{{\ \rm per\ cent}}$. Only nine candidate systems composed of two UCDs were identified. The sample of candidate multiple systems is made up of five triple systems and one quadruple system. The majority of the UCDs found in binaries and multiples are of early L type and the typical wide binary fraction over the L spectral types is $2\!-\!4{{\ \rm per\ cent}}$. Our sample of candidate wide binaries with UCDs as secondaries constitutes a substantial increase over the known number of such systems, which are very useful to constrain the formation and evolution of UCDs.
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Vasconcelos, Ivan, Roel Snieder, and Brian Hornby. "Imaging internal multiples from subsalt VSP data — Examples of target-oriented interferometry." GEOPHYSICS 73, no. 4 (2008): S157—S168. http://dx.doi.org/10.1190/1.2944168.
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Seismic interferometry has become a technology of growing interest for imaging borehole seismic data. We demonstrate that interferometry of internal multiples can be used to image targets above a borehole receiver array. By internal multiples, we refer to all types of waves that scatter multiple times inside the model. These include, for instance, interbed, intrasalt, and water-bottom multiples as well as conversions among them. We use an interferometry technique that is based on representation theorems for perturbed media and targets the reconstruction of specific primary reflections from multiply reflected waves. In this interferometry approach, we rely on shot-domain wavenumber separation to select the directions of waves arriving at a given receiver. Using a numerical walkaway (WAW) VSP experiment recorded by a subsalt borehole receiver array in the Sigsbee salt model, we use the interference of internal multiples to image the salt structure from below. In this numerical example, the interferometric image that uses internal multiples reconstructs the bottom- and top-of-salt reflectors above the receiver array as well as the subsalt sediment structure between the array and the salt. Because of the limited source summation in this interferometry example, the interferometric images show artifact reflectors within the salt body. We apply this method to a field walkaway VSP from the Gulf of Mexico. With the field data, we demonstrate that the choice of shot-domain wavenumbers in the target-oriented interferometry procedure controls the wavenumbers in the output pseudoshot gathers. Target-oriented interferometric imaging from the 20-receiver array recovers the top-of-salt reflector that is consistent with surface seismic images. We present our results with both correlation-based and deconvolution-based interferometry.
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KAO, CHEN-HUNG, and MIAO-HUI ZENG. "An investigation of the power for separating closely linked QTL in experimental populations." Genetics Research 92, no. 4 (2010): 283–94. http://dx.doi.org/10.1017/s0016672310000273.
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SummaryHu & Xu (2008) developed a statistical method for computing the statistical power for detecting a quantitative trait locus (QTL) located in a marker interval. Their method is based on the regression interval mapping method and allows experimenters to effectively investigate the power for detecting a QTL in a population. This paper continues to work on the power analysis of separating multiple-linked QTLs. We propose simple formulae to calculate the power of separating closely linked QTLs located in marker intervals. The proposed formulae are simple functions of information numbers, variance inflation factors and genetic parameters of a statistical model in a population. Both regression and maximum likelihood interval mappings suitable for detecting QTL in the marker intervals are considered. In addition, the issue of separating linked QTLs in the progeny populations from an F2 subject to further self and/or random mating is also touched upon. One of the primary keys to our approach is to derive the genotypic distributions of three and four loci for evaluating the correlation structures between pairwise unobservable QTLs in the model across populations. The proposed formulae allow us to predict the power of separation when several factors, such as sample sizes, sizes and directions of QTL effects, distances between QTLs, interval sizes and relative QTL positions in the intervals, are considered together at a time in different experimental populations. Numerical justifications and Monte Carlo simulations were provided for confirmation and illustration.
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WHEELER, SARITA RAENGPRADUB, PRECIAUS HEARD, CHRISTOPHE DUFOUR, et al. "Detection of Non-O157 Shiga Toxin–Producing Escherichia coli in 375 Grams of Beef Trim Enrichments across Multiple Commercial PCR Detection Platforms." Journal of Food Protection 78, no. 1 (2015): 196–202. http://dx.doi.org/10.4315/0362-028x.jfp-14-263.
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Although serotype O157:H7 remains the pathogenic Shiga toxin–producing Escherichia coli (STEC) of primary concern worldwide, some focus in the United States has shifted to six particular non-O157 STEC serogroups (O26, O45, O103, O111, O121, and O145). Some of these serogroups have also emerged as concerns elsewhere around the world, including Europe. The objective of this work was to compare commercial detection methods with the U.S. Department of Agriculture (USDA) reference method for detection of non-O157 STEC in 375 g of beef trim using a limit of detection study design. Overall, the commercial platforms performed well, showing similar levels of sensitivity for detection of presumptive positives for O45, O26, O103, and O121 (PCR screen results only). For O111, one method that utilizes an integrated immunomagnetic separation and PCR approach was more sensitive than a PCR-only screen approach. Additionally, one commercial method showed more presumptive and confirmed positives overall. Use of an immunomagnetic separation tool, such as antibody-coated beads, aided considerably with the confirmation procedures and is an important step when confirming suspect samples. A secondary goal of this study was to evaluate isolation and International Organization for Standardization confirmation protocols used in Europe compared with strategies provided by the USDA Microbiology Laboratory Guidebook (MLG). Generally, results from the USDA confirmation plates (modified Rainbow agar) were better than the European Union confirmation plates (MacConkey agar with or without rhamnose). In summary, detection of non-O157 STEC in 375 g of beef trim can be performed by any of the three methods on the market evaluated in the study.
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Calimeri, Teresa, Edmondo Battista, Francesco Conforti, et al. "SCID-Synth-Hu: a Novel Multiple Myeloma Model for In Vivo Expansion of Primary Cells." Blood 116, no. 21 (2010): 452. http://dx.doi.org/10.1182/blood.v116.21.452.452.
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Abstract Abstract 452 The critical role of the human bone marrow microenvironment (HuBMM) in the pathogenesis of Multiple Myeloma (MM) has recently allowed the design of novel therapeutical approaches targeting not only MM cells but also their specific HuBMM. However, the lack of adequate mouse models, capable to recapitulate a HuBMM, has restrained large scale in vivo screening of investigational drugs. In fact, only the SCID-hu model, in which human MM cells are grown in human fetal bone chips previously implanted in SCID mice, addresses this specific requirement. However the poor availability of human fetal bone chips, the allogeneic nature of the fetal BM milieu versus MM cells and the heterogeneity of implanted human bone chips are important restrains of this system. Here we report the development of a novel in vivo model of human MM (SCID-synth-hu), which is based on the implant of a three-dimensional (3-D) poly-ε-caprolactone polymeric scaffold (PCLS) into SCID mice as recipient to allow growth of MM cells in a reconstituted HuBMM. This biosynthetic scaffold has been designed to resemble the micro-architecture of a normal human adult bone and was characterized by 3-D interconnected large and small pores suitable for engraftment of bone marrow-derived cells. Human bone marrow stromal cells (BMSCs) were collected from BM aspirates from MM patients and firstly used for coating 3D internal surface of PCLSs. We performed in vitro dynamic seeding of BMSCs into PCLSs using a suspension of 106 cells in 500 μl of growth medium. Before implantation, PCLSs were incubated in complete medium at 37°C, in 5% CO2 for 24 hours, in order to allow cell adhesion on 3D surfaces. Then, PCLSs were implanted subcutaneously into SCID mice. CD138+ immune-selected primary MM cells, obtained by MM patient with a different disease status, were directly injected into PCLSs, which have been previously coated with allogeneic BMSCs 2–3 weeks after the in vivo implant. By this experimental approach, we achieved engraftment of primary MM cells in PCLSs within a non autologous bone marrow milieu. In a subsequent series of experiments, bone marrow mononuclear cells (BMMCs), obtained by Ficoll gradient separation and containing primary unselected CD138+ and their autologous BMSCs, were directly seeded in vitro into PCLSs which were implanted in SCID mice after 24 hours of incubation. At different time points, H&E and CD138 or κ/λ staining demonstrated engraftment and filling of 3-D spaces by primary MM cells within the autologous bone marrow milieu in PCLSs retrieved from SCID-synth-hu mice. Neo-synthesized extracellular matrix and angiogenesis were also shown by H&E and immune histochemical staining in retrieved PCLSs. Angiogenesis mostly occurred within areas of MM infiltration, suggesting its role in our system. In vivo MM growth was monitored by ELISA measuring of human monotypic immunoglobulins (Igs) in mouse sera 4 to 10 weeks after cell injection. To demonstrate the usefulness of our SCID-synth-hu model as an experimental platform for in vivo testing of investigational drugs, mice bearing human MM implants were treated intraperitoneally with bortezomib plus dexamethasone (Bort+Dex). As expected, SCID-synth-hu mice treated with Bort+Dex exhibited a significant decrease of monotypic light chains in mice sera and induction of apoptosis of MM cells in retrieved PCLSs, as compared to untreated control mice. Our experimental findings demonstrate that the SCID-synth-hu is the first experimental system which allows the in vivo expansion of human primary MM cells within their autologous adult HuBMM. The unlimited availability and the low cost of PCLSs, as well as the potential for dissecting the biological events within the HuBMM, represent a clear improvement over the available preclinical in vivo models of MM. We conclude that the SCID-synth-hu is a unique tool for large scale in vivo preclinical screening of novel agents targeting MM in its autologous HuBMM, and a novel resource for translational research in the experimental treatment of this still incurable disease. Disclosures: No relevant conflicts of interest to declare.
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Bolognesi, Maddalena Maria, Marco Manzoni, Carla Rossana Scalia, et al. "Multiplex Staining by Sequential Immunostaining and Antibody Removal on Routine Tissue Sections." Journal of Histochemistry & Cytochemistry 65, no. 8 (2017): 431–44. http://dx.doi.org/10.1369/0022155417719419.
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Multiplexing, labeling for multiple immunostains in the very same cell or tissue section in situ, has raised considerable interest. The methods proposed include the use of labeled primary antibodies, spectral separation of fluorochromes, bleaching of the fluorophores or chromogens, blocking of previous antibody layers, all in various combinations. The major obstacles to the diffusion of this technique are high costs in custom antibodies and instruments, low throughput, and scarcity of specialized skills or facilities. We have validated a method based on common primary and secondary antibodies and diffusely available fluorescent image scanners. It entails rounds of four-color indirect immunofluorescence, image acquisition, and removal (stripping) of the antibodies, before another stain is applied. The images are digitally registered and the autofluorescence is subtracted. Removal of antibodies is accomplished by disulfide cleavage and a detergent or by a chaotropic salt treatment, this latter followed by antigen refolding. More than 30 different antibody stains can be applied to one single section from routinely fixed and embedded tissue. This method requires a modest investment in hardware and materials and uses freeware image analysis software. Multiplexing on routine tissue sections is a high throughput tool for in situ characterization of neoplastic, reactive, inflammatory, and normal cells.
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Manara, C. F., M. Tazzari, F. Long, et al. "Observational constraints on dust disk sizes in tidally truncated protoplanetary disks in multiple systems in the Taurus region." Astronomy & Astrophysics 628 (August 2019): A95. http://dx.doi.org/10.1051/0004-6361/201935964.
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The impact of stellar multiplicity on the evolution of planet-forming disks is still the subject of debate. Here we present and analyze disk structures around ten multiple stellar systems that were included in an unbiased, high spatial resolution survey performed with ALMA of 32 protoplanetary disks in the Taurus star-forming region. At the unprecedented spatial resolution of ~0.12′′ we detect and spatially resolve the disks around all primary stars, and those around eight secondary and one tertiary star. The dust radii of disks around multiple stellar systems are smaller than those around single stars in the same stellar mass range and in the same region. The disks in multiple stellar systems also show a steeper decay of the millimeter continuum emission at the outer radius than disks around single stars, suggestive of the impact of tidal truncation on the shape of the disks in multiple systems. However, the observed ratio between the dust disk radii and the observed separation of the stars in the multiple systems is consistent with analytic predictions of the effect of tidal truncation only if the eccentricities of the binaries are rather high (typically >0.5) or if the observed dust radii are a factor of two smaller than the gas radii, as is typical for isolated systems. Similar high-resolution studies targeting the gaseous emission from disks in multiple stellar systems are required to resolve this question.
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Franz, A. P., L. Rateke, T. Hartmann, et al. "Separation anxiety disorder in adult patients with obsessive-compulsive disorder: Prevalence and clinical correlates." European Psychiatry 30, no. 1 (2015): 145–51. http://dx.doi.org/10.1016/j.eurpsy.2014.04.007.
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AbstractObjective:Individuals with obsessive-compulsive disorder (OCD) and separation anxiety disorder (SAD) tend to present higher morbidity than do those with OCD alone. However, the relationship between OCD and SAD has yet to be fully explored.Method:This was a cross-sectional study using multiple logistic regression to identify differences between OCD patients with SAD (OCD + SAD, n = 260) and without SAD (OCD, n = 695), in terms of clinical and socio-demographic variables. Data were extracted from those collected between 2005 and 2009 via the Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders project.Results:SAD was currently present in only 42 (4.4%) of the patients, although 260 (27.2%) had a lifetime diagnosis of the disorder. In comparison with the OCD group patients, patients with SAD + OCD showed higher chance to present sensory phenomena, to undergo psychotherapy, and to have more psychiatric comorbidities, mainly bulimia.Conclusion:In patients with primary OCD, comorbid SAD might be related to greater personal dysfunction and a poorer response to treatment, since sensory phenomena may be a confounding aspect on diagnosis and therapeutics. Patients with OCD + SAD might be more prone to developing specific psychiatric comorbidities, especially bulimia. Our results suggest that SAD symptom assessment should be included in the management and prognostic evaluation of OCD, although the psychobiological role that such symptoms play in OCD merits further investigation.
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Victor, Mark A., and Stanley R. Crouch. "Absorbance-Corrected Synchronous Fluorescence with a Fiber-Optic-Based Fluorometer." Applied Spectroscopy 49, no. 7 (1995): 1041–47. http://dx.doi.org/10.1366/0003702953964778.
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Synchronous fluorescence spectroscopy is frequently used to resolve multiple components in mixtures without separation. However, uncompensated inner-filter effects can lead to unexpected and/or large quantitative errors. An instrument and a method that correct for primary and secondary inner-filter effects in synchronous fluorescence spectroscopy have been designed and characterized. A bifurcated fiber-optic-based diode array fluorometer that simultaneously measures front-surface fluorescence and absorbance was constructed. A transfer function that mathematically describes the coupling efficiency between the excitation and emission legs of the fiber optics is defined and characterized. Once characterized, such a fluorometer is capable of calculating what the fluorescence measurement would be in the absence of inner-filter effects. Several experimental procedures for determining the instrument's transfer function are compared and discussed. Applications of the various procedures to experimental fluorescence inner-filter corrections to problematic samples are demonstrated.
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Ma, Ying, Jie-Qiong Cao, Yan Yin, et al. "Rare case of uterine neoplasm: cervical sarcoma with endometrial carcinoma." Journal of International Medical Research 48, no. 3 (2019): 030006051987679. http://dx.doi.org/10.1177/0300060519876792.
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Multiple primary malignant tumors (MPMTs) refer to two or more primary malignant neoplasms that simultaneously or successively occur in one or more organs in the same individual. Cervical sarcoma concomitant with endometrial carcinoma is rare. A 46-year-old woman was admitted because of increased menstrual volume for 4 years and irregular vaginal bleeding with discharge for 6 months. The diagnosis of endometrial carcinoma at stage II was made on the basis of results of ultrasound, pelvic magnetic resonance imaging, and hysteroscopic curettage. Extensive total abdominal hysterectomy + bilateral adnexectomy + bilateral ovarian arteriovenous high ligation + pelvic adhesion separation + pelvic lymphadenectomy +abdominal aortic lymphadenectomy via the abdomen were performed. Postoperative diagnosis of cervical sarcomas with endometrial carcinoma in stage IIIC1 was made according to the results of pathology and immunohistochemistry. Six cycles of cisplatin-epirubicin-isocyclophosphamide treatment were provided after the operation. Most clinical manifestations of cervical sarcomas are abnormal vaginal bleeding. Use of preoperative imaging and hysteroscopy is difficult for diagnosing cervical sarcomas, and postoperative pathological examinations and immunohistochemical diagnosis are mainly used instead. The possibility of MPMTs should be considered for endometrial carcinoma, especially if the cervical lesion is larger than that of the uterine cavity.
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Tu, Yuan-Kai, Jui-Sheng Lai, Bo-Jein Kuo, Ruo-Han Jian, and Tsing-Fen Ho. "Determining the effective compounds of Salvia miltiorrhiza through chromatographic fingerprinting coupled with chemometrics." Advancement in Medicinal Plant Research 9, no. 3 (2021): 48–58. http://dx.doi.org/10.30918/ampr.93.21.014.
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Herbs are rich in the active ingredients of drugs for preventing or treating various disorders. However, conventional bioactivity-guided separation is time and labor-intensive and neglects the additive effect of multiple components. These problems hinder the development of new medicines from natural products. This study established a chemometric analysis method that integrates processes based on the spectrum-effect relationship for the rapid identification of the primary active components of a plant. The high-performance liquid chromatography (HPLC) fingerprints of 171 Salvia miltiorrhiza extracts (SMEs) with varied constituent profiles were analyzed. Chemometric analysis was performed to establish an HPLC fingerprint–bioactivity relationship to explore the components of SMEs that contribute to the antioxidant activity and cytotoxicity effect, respectively. The results indicated that the developed strategy can be used to identify components largely contributing to particular bioactivities and re-evaluate the efficacy of previously neglected components. The present study identified not only the primary active components of S. miltiorrhiza but also the optimal ratios of constituents, validating the method for use in the future investigation and development of herbal medicines. Keywords: Chemometric, herb, antioxidant, cytotoxicity, fingerprint, Salvia miltiorrhiza.
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Lloyd, Helen, Ben Fosh, Ben Whalley, Richard Byng, and James Close. "Validation of the person-centred coordinated care experience questionnaire (P3CEQ)." International Journal for Quality in Health Care 31, no. 7 (2018): 506–12. http://dx.doi.org/10.1093/intqhc/mzy212.
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Abstract Background Measuring patient experiences of healthcare is increasingly emphasized as a mechanism to measure, benchmark and drive quality improvement, clinical effectiveness and patient safety at both national and local NHS level. Person-centred coordinated care (P3C) is the conjunction of two constructs; person-centred care and care coordination. It is a complex intervention requiring support for changes to organizational structure and the behaviour of professionals and patients. P3C can be defined as: ‘care and support that is guided by and organized effectively around the needs and preferences of individuals’. Despite the vast array of PRMS available, remarkably few tools have been designed that efficiently probe the core domains of P3C. This paper presents the psychometric properties of a newly developed PREM to evaluate P3C from a patient perspective. Methods A customized EMIS search was conducted at 72 GP practices across the South West (Somerset, Devon and Cornwall) to identify 100 patients with 1 or more LTCs, and are frequent users of primary healthcare services. Partial Credit Rasch Modelling was conducted to identify dimensionality and internal consistency. Ecological validity and sensitivity to change were assessed as part of intervention designed to improve P3C in adults with multiple long-term conditions; comparisons were drawn between the P3CEQ and qualitative data. Results Response rate for the P3CEQ was 32.82%. A two-factor model was identified. Rasch analysis confirmed unidimensionality of each factor (using infit MSQ values between 0.5 and 1.5). High internal consistency was established for both factors; For the Person-centred scale Cronbach’s Alpha = 0.829, Person separation = 0.756 and for the coordination scale Cronbach’s alpha = 0.783, person separation = 0.672. Conclusions The P3CEQ is a valid and reliable measure of P3C. The P3C is considered to have strong face, construct and ecological validity, with demonstrable sensitivity to change in a primary healthcare intervention.