Analyzing the effectiveness of receiver arrays for multicomponent seismic exploration

Geophysics ◽  
2002 ◽  
Vol 67 (6) ◽  
pp. 1853-1868 ◽  
Author(s):  
Brian H. Hoffe ◽  
Gary F. Margrave ◽  
Robert R. Stewart ◽  
Darren S. Foltinek ◽  
Henry C. Bland ◽  
...  
Keyword(s):  
Oil Field ◽  
Seismic Exploration ◽  
Common Source ◽  
Coherent Noise ◽  
Significant Deterioration ◽  
Seismic Line ◽  
Noise Rejection ◽  
Seismic Image ◽  
Receiver Arrays

This paper uses an experimental seismic line recorded with three‐component (3C) receivers to develop a case history demonstrating very little benefit from receiver arrays as compared to point receivers. Two common array designs are tested; they are detrimental to the P‐S wavefield and provide little additional benefit for P‐P data. The seismic data are a 3C 2‐D line recorded at closely spaced (2 m) point receivers over the Blackfoot oil field, Alberta. The 3C receiver arrays are constructed by summing five (one group interval) and ten (two group intervals) point receivers. The shorter array emphasizes signal preservation while the longer array places priority on noise rejection. The effectiveness of the arrays versus the single geophones is compared in both the t−x and f−k domains of common source gathers. The quality of poststack data is also compared by analyzing the f−x spectra for signal bandwidth on both the vertical receiver component (P‐P) and radial receiver component (P‐S) structure stacks produced using these two array design philosophies. The prestack analysis shows that the two arrays effectively suppress coherent noise on both the vertical and radial geophone data and perform reasonably as spatial antialias filters. The poststack analysis reveals that, for both the P‐P and P‐S data, neither of the two arrays significantly improves the quality of the final seismic image over that obtained from point receiver data. For the P‐P data there are subtle differences between the final stacked sections, while for the P‐S data there is a significant deterioration in image quality from the application of the arrays. This P‐S image deterioration is attributed to significant variation of shear‐wave statics across the array. For this specific survey area and acquisition parameters, 3C receiver arrays are unnecessary for P‐P data and are detrimental to P‐S data.

Spatial filtering of marine seismic data

Geophysics ◽  
1983 ◽  
Vol 48 (12) ◽  
pp. 1611-1630 ◽  
Author(s):  
Bjørn Ursin
Keyword(s):  
Linear Time ◽  
Three Dimensional ◽  
Seismic Exploration ◽  
Common Source ◽  
Coherent Noise ◽  
Extended Source ◽  
Reflected Waves ◽  
Receiver Array ◽  
Marine Seismic ◽  
Source Array

Extended source and receiver arrays have proved to be an effective tool for improving the data quality in marine seismic exploration. The extended arrays may be implemented in the field, or in a computer by the summation of traces with a common receiver coordinate or a common source coordinate, respectively. A tilted source or receiver array may be used to enhance reflectors with a specific dip. A tilted source array can be implemented in the field by delaying the pulses at the source subarrays, or in the computer by time‐shifting the traces before implementing the long source array. A tilted receiver array can approximately be implemented in the computer by time‐shifting the traces before implementing the long receiver array. In areas with complex geologic structure, the data can be corrected for normal moveout prior to implementing the extended arrays. The theoretical response of reflected waves from dipping reflectors for different extended array filters is given. Vertical and horizontal stacking constitute a spatial filter which is similar to an extended array filter. Vertical stacking with linear time shifts between the traces can be used to enhance reflectors with a specific dip. The theoretical response of reflected waves from dipping reflectors for different vertical and horizontal stacking filter is given. In order to discriminate against coherent noise travelling in the cross‐line direction, areal arrays must be used. The theoretical responses of three‐dimensional spatial filters are derived in the appendices. These responses are based on quadratic traveltime approximations for reflections in inhomogeneous layered media. A data example is presented which demonstrates the practical use of extended array filters, both implemented in the field and in the computer. From this example and others have come the following conclusions. In areas with strong coherent noise, a field‐implemented extended source array gives a signal‐to‐coherent noise improvement which cannot be obtained in data processing. In other areas, computer implementation of the extended arrays gives signal‐to‐coherent noise improvement as effectively as a field‐implemented extended source array. In such cases, the extended array filters should be implemented in the computer due to greater flexibility in testing on data and to the possibility of producing different stacked sections. Noise reduction is done more effectively by extended array filtering than by vertical and horizontal stacking prior to CDP stacking (weighted or unweighted full‐fold horizontal stacking).

scholarly journals Coherent Noise Attenuation Using AGORA Filter on 2D Seismic Data in East Diwaniya, South Eastern – Iraq

2019 ◽  
Vol 60 (5) ◽  
pp. 1049-1054
Author(s):  
Kamal K. Ali ◽  
Reem Kh. Ibraheem ◽  
Hassan A. Thabit
Keyword(s):  
Seismic Signal ◽  
High Ratio ◽  
Guided Wave ◽  
Quality Of Data ◽  
Coherent Noise ◽  
Seismic Line ◽  
South Eastern ◽  
Ground Roll ◽  
Good Signal

Coherent noise such as ground roll and guided wave is present in the seismic line DE21 (East Diwaniya south eastern Iraq) and it obscures seismic signal and degrades from the quality of data. To attenuate the coherent noise from the shot gather and the Stack of the seismic line, AGORA filter was applied in order to obtain the good signal as the hyperbola shape in shot gather and the reflectors will be clearly to interpret it later. It has given good results and the coherent noise was attenuated in high ratio on all the line. The spectrum analysis is confirmed the effectiveness of AGORA filter to attenuate the coherent noise. 

Mesenchymal Stem Cells in the Treatment of Cartilage Defects of the Knee: A Systematic Review of the Clinical Outcomes

2021 ◽  
pp. 036354652098681
Author(s):  
Monketh Jaibaji ◽  
Rawan Jaibaji ◽  
Andrea Volpin
Keyword(s):  
Systematic Review ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Osteochondral Lesions ◽  
Common Source ◽  
Significant Heterogeneity ◽  
Osteochondral Defects

Background: Osteochondral lesions are a common clinical problem and their management has been historically challenging. Mesenchymal stem cells have the potential to differentiate into chondrocytes and thus restore hyaline cartilage to the defect, theoretically improving clincal outcomes in these patients. They can also be harvested with minimal donor site morbidity. Purpose: To assess the clinical and functional outcomes of mesenchymal stem cell implantation to treat isolated osteochondral defects of the knee. A secondary purpose is to assess the quality of the current available evidence as well as the radiological and histological outcomes. We also reviewed the cellular preparation and operative techniques for implantation. Study Design: Systematic review. Methods: A comprehensive literature search of 4 databases was carried out: CINAHL, Embase, MEDLINE, and PubMed. We searched for clinical studies reporting the outcomes on a minimum of 5 patients with at least 12 months of follow-up. Clinical, radiological, and histological outcomes were recorded. We also recorded demographics, stem cell source, culture technique, and operative technique. Methodological quality of each study was assessed using the modified Coleman methodology score, and risk of bias for the randomized controlled studies was assessed using the Cochrane Collaboration tool. Results: Seventeen studies were found, encompassing 367 patients. The mean patient age was 35.1 years. Bone marrow was the most common source of stem cells utilized. Mesenchymal stem cell therapy consistently demonstrated good short- to medium-term outcomes in the studies reviewed with no serious adverse events being recorded. There was significant heterogeneity in cell harvesting and preparation as well as in the reporting of outcomes. Conclusion: Mesenchymal stem cells demonstrated a clinically relevant improvement in outcomes in patients with osteochondral defects of the knee. More research is needed to establish an optimal treatment protocol, long-term outcomes, and superiority over other therapies. Registration: CRD42020179391 (PROSPERO).

Do we achieve the Montgomery standard for consent in orthopaedic surgery?

2021 ◽  
pp. 1-7
Author(s):  
Xenia N Tonge ◽  
Henry Crouch-Smith ◽  
Vijay Bhalaik ◽  
William D Harrison
Keyword(s):  
Treatment Options ◽  
Information Provision ◽  
Common Source ◽  
Health Board ◽  
Improvement Project ◽  
Specific Patient ◽  
Written Information ◽  
Orthopaedic Patients ◽  
Recorded Data

Aims/Background The Montgomery v Lanarkshire Health Board (2015) case set a precedent that has driven the modernisation of consenting practice. Failure to demonstrate informed consent is a common source of litigation. This quality improvement project aimed to provide pragmatic guidance for surgeons on consent and to improve the patient experience during decision making. Methods Elective orthopaedic patients were assessed and the quality of documented consent was recorded. Data were collected over two discrete cycles, with cycle 1 used as a baseline in practice. The following criteria were reviewed: grade of consenting clinician, alternative treatment options, description of specific risks, place and timing of consent and whether the patient received written information or a copied clinic letter. Cycle 1 results were presented to clinicians; a teaching session was provided for clinicians on the standard of consent expected and implementation of a change in practice was established with a re-audit in cycle 2. Results There were 111 patients included in cycle 1, and 96 patients in cycle 2. Consent was undertaken mostly by consultants (54%). Specific patient risks were documented in 50% of patients in cycle 1 and 60% in cycle 2. Risks associated with a specific procedure were documented in 42% in cycle 1 and 76% in cycle 2, alternative options in 48% (cycle 1) and 66% (cycle 2). A total of 14% of patients in cycle 1 and 8% in cycle 2 had documented written information provision. Copied letters to patients was only seen in 12% of all cycles. Documentation from dedicated consenting clinics outperformed standard clinics. Conclusions Highlighting poor documentation habits and refining departmental education can lead to improvements in practice. The use of consenting clinics should be considered and clinicians should individually reflect on how to address their own shortcomings. Other units should strongly consider a similar audit. This article provides stepwise advice to improve consent and specifics from which to audit.

scholarly journals Quality of shallow groundwater and manure effluents in a livestock farm

2016 ◽  
Vol 29 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Sylwester Smoroń
Keyword(s):  
Water Quality ◽  
Shallow Groundwater ◽  
Vegetable Crops ◽  
Drainage Ditch ◽  
Significant Deterioration ◽  
Research Material ◽  
Drinking Purposes ◽  
Livestock Buildings ◽  
Manure Storage

Abstract The aim of the study was to assess the quality of shallow groundwater on the site pens and runoff from livestock manure heaps, in three selected farms involved in animal production and vegetable crops in the area of Plateau Proszowice. The analysis mainly included water from farm wells and effluents from manure. Additionally, water from drainage ditch running nearby farms was collected, before inflow of effluent (i.e. ditch water without manure effluent) and below inflow of effluent from heap of manure (i.e. ditch water containing manure effluent). Samples of the research material were collected from April 2012 to March 2014 at monthly intervals and analysed for the content of NO3-N, NH4-N, PO4-P, K, Na and Cl. Based on the obtained results it was found that water from the farm wells near the livestock buildings and from manure storage sites, was heavily polluted by the majority of these contaminants. The highest concentration of these pollutants, except for the NO3-N, was found in manure effluent – it exceeded a few dozen to a few hundred to any standards for water quality. There was also a significant deterioration in the quality of drainage ditch water because of the penetration of contaminants into ditch water from heaps of improperly stored manure. The water of the farm wells was characterized by excessive concentrations of NO3-N which disqualified it for drinking purposes.

scholarly journals The Mesozoic of the South Caspian oil and gas province, Southwestern Turkmenistan – prospects for gas and oil exploration

2021 ◽  
pp. 102-133
Author(s):  
V.N. Melikhov ◽  
N.A. Krylov ◽  
I.V. Shevchenko ◽  
V.L. Shuster
Keyword(s):  
Oil And Gas ◽  
High Efficiency ◽  
State Of The Art ◽  
Oil Field ◽  
Seismic Exploration ◽  
Oil Exploration ◽  
The South ◽  
Analytical Review ◽  
Drilling Operations ◽  
Low Efficiency

Regarding the South Caspian oil and gas province, it is concluded that the Pliocene productivity prevails in the western part of the province, and that the gas and oil prospects of the eastern land side in the Mesozoic are prioritized. A retrospective analytical review of geological and geophysical data and publications on the Mesozoic of Southwestern Turkmenistan was carried out, which showed the low efficiency of the performed seismic and drilling operations in the exploration and evaluation of very complex Mesozoic objects. A massive resumption of state-of-the-art seismic exploration and appraisal drilling in priority areas and facilities performed by leading Russian companies is proposed. For some areas, a new, increased estimate of the projected gas resources is given. An example of modern high-efficiency additional exploration of the East Cheleken, a small Pliocene gas and oil field, which turned this field into a large one in terms of reserves, is given.

scholarly journals Why Early Diagnosis Is Better for Alzheimer’s Patients

2009 ◽  
Vol 4 (1) ◽  
pp. 10
Author(s):  
Thierry Voisin ◽  
Sandrine Sourdet ◽  
Julien Delrieu ◽  
Bruno Vellas ◽  
◽  
...  
Keyword(s):  
Quality Of Life ◽  
General Practitioner ◽  
Cognitive Function ◽  
Early Diagnosis ◽  
Family Members ◽  
Special Role ◽  
Significant Deterioration ◽  
Common Cause ◽  
Care Givers

Alzheimer’s disease (AD) is the most common cause of dementia. AD progression leads to a significant deterioration in cognitive function, resulting in a significant impact not only on patient quality of life but also on the quality of life of family members/care-givers. Some physicians do not feel that diagnosing AD is necessary due to the absence of any cure and the stress related to diagnosis. Nevertheless, it is important to diagnose AD as early as possible. Early diagnosis of AD allows the patient to be more involved in treatment planning, since at this stage the patient’s cognitive function will be near normal. Many forms of the disease do not progress rapidly, and early diagnosis and treatment will allow a good quality of life for the patient, family members and care-givers. The general practitioner has a special role in detecting and following up patients diagnosed with AD.

scholarly journals El sector de la construcción en la provincia de León a lo largo del periodo 1990-2013 = The construction industry in the province of León during the period 1990-2013

2014 ◽  
pp. 65
Author(s):  
Pedro María Martínez Villar
Keyword(s):  
Construction Industry ◽  
Recovery Phase ◽  
Output Level ◽  
Economic Cycle ◽  
Significant Deterioration ◽  
Competitive Position ◽  
Construction Activity ◽  
High Degree ◽  
New Jobs

<p class="Formatolibre">El sector de la construcción a lo largo del periodo 1990-2013 ha protagonizado un papel fundamental en el desarrollo de la provincia de León al haber contribuido a mejorar la posición competitiva provincial, así como las condiciones de vida de los ciudadanos al haber proporcionado elementos de bienestar básicos para la sociedad.</p><p class="Formatolibre">El comportamiento sectorial de la construcción a lo largo de los años analizados, a grandes rasgos y salvando ciertas particularidades, ha replicado el ciclo económico vivido a nivel nacional. De esta forma, el sector de la construcción leonés ha participado de la etapa de recuperación de la crisis anterior de 1992-1993 durante los años 1995-1999. A partir del año 2000 y hasta el 2009 el sector vive una intensa fase expansiva, llegando a aportar el 12,62% del PIB provincial y el 14% del empleo. A partir del 2010, y con casi 18 meses de retraso respecto al inicio de la crisis a nivel nacional, el sector empezó a mostrar alarmantes signos de debilidad, experimentando una intensa y duradera depresión que ha afectado al  nivel de output de otros sectores que tienen un elevado grado de dependencia de la construcción.</p><p class="Formatolibre">A pesar de la intensa crisis sufrida por este sector desde 2007, la actividad constructora sigue siendo importante para el conjunto de la economía provincial, puesto que el 17,36% del total de las empresas leonesas tienen actividad directa con la construcción y sigue aportando cifras próximas al 10% del VAB provincial y en términos de empleo el sector sigue dando empleo a 15.200 trabajadores en la provincia de León. En este sentido, es necesario indicar que la crisis, además de haber expulsado a un notable número de trabajadores del sector,  ha causado un deterioro importante de la calidad contractual de las nuevas incorporaciones, incrementándose la temporalidad y una reducción notable de los salarios como principales características de ajuste del mercado de trabajo sectorial.</p><p class="Formatolibre">The construction industry over the period 1990-2013 has carried out a fundamental role in the development of the Province of Leon, as it has contributed to the improvement of its competitive position and living conditions of its inhabitants and has provided wellness infraestructure, basic to society.</p><p class="Formatolibre">The performance of the construction industry over the years analyzed has broadly, and saving certain peculiarities, replicated the economic cycle experienced nationwide. Thus, the construction industry of the province of Leon has participated in the recovery phase of the previous crisis of 1992-1993 during the years 1995-1999. From 2000 and until 2009 the industry faced an intense upswing, reaching 12.62% contribution to the provincial GDP and 14% of employment. It was on 2010, almost 18 months later than the beginning of the nationwide crisis, when the sector began to show worrying signs of weakness, experiencing an intense and lasting depression that has affected the production and output level of other sectors that have a high degree of dependence on construction industry.</p><p class="Formatolibre">Despite the intense crisis experienced by the sector since 2007, construction activity remains important for the entire provincial economy. Forasmuch as 17.36% of the total of Leon companies have direct activity with construction and its industry continues to provide figures close to 10% of the provincial VAB in terms of employment and the sector still employs 15,200 workers in the province. In this sense, the fact remains that the crisis not only has driven a significant number of workers out of the sector, but it has also caused a significant deterioration of the contractual quality of the new jobs, and resulting in a significant reduction in wages as major characteristics of work sector market adjustment.</p>

Subthalamic Nucleus Deep Brain Stimulation May Improve Pain in the Setting of Parkinson Disease

2020 ◽  
pp. 85-88
Author(s):  
Anjali Gera ◽  
Gian Pal
Keyword(s):  
Chronic Pain ◽  
Deep Brain Stimulation ◽  
Parkinson Disease ◽  
Subthalamic Nucleus ◽  
Brain Stimulation ◽  
Foot Deformities ◽  
Common Source ◽  
Constant Pain ◽  
Deep Brain

More than 50% of patients with Parkinson disease (PD) can have chronic pain. PD pain has been associated with reduced quality of life scores on validated measures. The most common source of PD pain is musculoskeletal in origin. This pain may manifest as rigidity, cramps, shoulder discomfort, spinal or hand and foot deformities, dystonic pain, or nonradicular back pain. Our case illustrates improvement in chronic pain following bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) surgery in a 45-year-old patient with PD. Approximately 1 year after PD onset, he developed constant pain and tremor in his left upper extremity, which gradually worsened over time. Initially, carbidopa/levodopa completely alleviated both his arm tremor and pain. Over the next several years, he developed off periods that were associated with bothersome tremor and pain, and on periods that were associated with prominent neck and left arm dyskinesia, both of which were associated with significant pain. At age 60 years, after 15 years of PD, he underwent bilateral STN DBS implantation. Following DBS, he had significant improvement in his left arm tremor, rigidity, motor fluctuations, and pain. He also had a 70% reduction in his dopaminergic medication and complete resolution of dyskinesia and neck pain.

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