2,379 research outputs found
2D-shear wave elastography : number of acquisitions can be reduced according to clinical setting
No full textAbstract: BACKGROUND The factors affecting intra-operator variability of two-dimensional shear wave elastography (2D-SWE) have not been clearly established. We evaluated 2D-SWE variability according to the number of measurements, clinical and laboratory features, and liver stiffness measurements (LSM). METHODS At least three LSM were performed in 452 patients who underwent LSM by 2D-SWE (supersonic shear imaging) out of an initial database of 1650 patients. The mean value of the three LSM was our best measurement method. Bland-Altman plots were used to evaluate intra-operator variability when considering only one, or the first two measurements. Variability was assessed by taking the absolute value of the difference between the first LSM and the mean of the three LSM. Logistic regression was used to assess the factors associated with the highest tertile of variability. RESULTS The limit of agreement was narrower with the mean of the first and second measurements than with each measurement taken separately (-\u20092.83 to 2.99\ua0kPa vs. -\u20095.86 to 6.21\ua0kPa and -\u20095.77 to 5.73\ua0kPa for the first and second measurement, respectively). A BMI\u2009 65\u200925\ua0kg/m2 and a first LSM by 2D-SWE\u2009 65\u20097.1\ua0kPa increased the odds of higher variability by 3.4 and 3.9, respectively. Adding a second LSM didn't change the variability in patients with BMI\u2009<\u200925 and a first LSM by 2D-SWE\u2009<\u20097.1\ua0kPa. CONCLUSIONS Intra-operator variability of LSM by 2D-SWE increases with both a high BMI and high LSM value. In patients with BMI\u2009<\u200925\ua0kg/m2 and a first LSM\u2009<\u20097.1\ua0kPa we recommend performing only one LSM
The churn among firms
No full textCapitalism ; Competition ; Consumers ; Consumption (Economics) ; Corporations ; Cost and standard of living ; Business enterprises ; Productivity
ORGANISATIONAL DEVELOPMENT OF LOCAL CIVIL SOCIETY ORGANISATIONS IN LAND SETOR; HARD SYSTEM APPROACH ( Than Myint Swe, 2019)
No full textCivil Society Organisations(CSOs) are playing a crucial role from community level to national level not only basic need of human being but also policy reform. The objectives of this study are to identify current status and activities of Civil Society Organisations in land sector and analyse their Organizational Development in term of Hard System such as Strategy, Structure and System. This study uses Mckinsey 7S model. According to the findings, the current status or activities of CSOs in land sector being worked and supported in community level, state and regional level and national level promoting and supporting on land law and land right awareness, conflict resolution, dialogue, workshop and advocacy related land policies and laws in Myanmar. It is also found that most of the CSOs in land sector have positive situations in Hard System except funding model component. This study suggests CSOs in land sector to promote the coordination and networking one another. They also should improve the appropriate funding model and maintain the current positive situations in Hard System
Assimilation of point SWE data into a distributed snow cover model comparing two contrasting methods
No full textIn alpine and high-latitude regions, water resource decision making often requires large-scale estimates of snow amounts and melt rates. Such estimates are available through distributed snow models which in some situations can be improved by assimilation of remote sensing observations. However, in regions with frequent cloud cover, complex topography, or large snow amounts satellite observations may feature information of limited quality. In this study, we examine whether assimilation of snow water equivalent (SWE) data from ground observations can improve model simulations in a region largely lacking reliable remote sensing observations. We combine the model output with the point data using three-dimensional sequential data assimilation methods, the ensemble Kalman filter, and statistical interpolation. The filter performance was assessed by comparing the simulation results against observed SWE and snow-covered fraction. We find that a method which assimilates fluxes (snowfall and melt rates computed from SWE) showed higher model performance than a control simulation not utilizing the filter algorithms. However, an alternative approach for updating the model results using the SWE data directly did not show a significantly higher performance than the control simulation. The results show that three-dimensional data assimilation methods can be useful for transferring information from point snow observations to the distributed snow model.Key PointsEvaluating methods for assimilating snow observations into distributed modelsAssimilation can improve model skill also at locations without observationsAssimilation of fluxes appears more successful than assimilation of states</ul
Consistency in the AMSR-E snow products: groundwork for a coupled snowfall and SWE algorithm
No full text2019 Fall.Includes bibliographical references.Snow is an important wintertime property because it is a source of freshwater, regulates land-atmosphere exchanges, and increases the surface albedo of snow-covered regions. Unfortunately, in-situ observations of both snowfall and snow water equivalent (SWE) are globally sparse and point measurements are not representative of the surrounding area, especially in mountainous regions. The total amount of land covered by snow, which is climatologically important, is fairly straightforward to measure using satellite remote sensing. The total SWE is hydrologically more useful, but significantly more difficult to measure. Accurately measuring snowfall and SWE is an important first step toward a better understanding of the impacts snow has for hydrological and climatological purposes. Satellite passive microwave retrievals of snow offer potential due to consistent overpasses and the capability to make measurements during the day, night, and cloudy conditions. However, passive microwave snow retrievals are less mature than precipitation retrievals and have been an ongoing area of research. Exacerbating the problem, communities that remotely sense snowfall and SWE from passive microwave sensors have historically operated independently while the accuracy of the products has suffered because of the physical and radiometric dependency between the two. In this study, we assessed the relationship between the Northern Hemisphere snowfall and SWE products from the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E). This assessment provides insight into regimes that can be used as a starting point for future improvements using coupled snowfall and SWE algorithm. SnowModel, a physically-based snow evolution modeling system driven by the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis, was employed to consistently compare snowfall and SWE by accounting for snow evolution. SnowModel has the ability to assimilate observed SWE values to scale the amount of snow that must have fallen to match the observed SWE. Assimilation was performed using AMSR-E, Canadian Meteorological Centre (CMC) Snow Analysis, and Snow Data Assimilation System (SNODAS) SWE to infer the required snowfall for each dataset. Observed AMSR-E snowfall and SWE were then compared to the MERRA-2 snowfall and SnowModel-produced SWE as well as SNODAS and CMC inferred snowfall and observed SWE. Results from the study showed significantly different snowfall and SWE bias patterns observed by AMSR-E. Specifically, snowfall was underestimated nearly globally and SWE had pronounced regions of over and underestimation. Snowfall and SWE biases were found to differ as a function of surface temperature, snow class, and elevation
An acoustical investigation of the concert harp
No full textThis thesis is a report of acoustical research on the concert harp.
The harp has an established place in the symphony orchestra and is
reacquiring its role as a solo chamber instrument that it had before the
development of the modern piano.
As far as can be determined, this is the first doctoral thesis on
the concert harp and serves as an introduction to the science of the
instrument, The experimental methods employed- holographic
interferonietry, input admittance measurements, Chiadni glitter pattern
methods, sound pressure level measurements- have all been successfully
used with work on other musical instruments. Theoretical calculations
are used to underpin the experimental results for several of the
subjects reported. The experimental results are also compared with the
results of similar tests on different musical instruments. Analyses of
the violin, guitar and piano are particularly used in discussions.
This work is specifically on the "Orchestra" concert harp,
manufactured and sold by the Salvi Harp organisation, though reference
Is made in Chapter 3 to the "Electra" concert harp, which is also a
Salvi harp. The "Orchestra" harp has a similar design to many other
concert harps built by different luthiers around the world.
This thesis is structured as follows. The first chapter is a review
of historical and contemporary research an stringed musical instruments.
The next chapter is a detailed description of the Salvi "Orchestra"
harps the dimensions of all the inportant features are given, the
tensions and materials of the strings are reported and there is also a
short description on the playing of the instrument.
The next five chapters form the kernal of the research report and
deal with the vibrations of the constituent part of the "Orchestra" and
finally the completed, strung harp itself. In Chapter 3, the vibrations
of the free soundboard are reported in some detail. Analysis is made at
a number of stages of the construction of the soundboard itself. The
position of the neutral axis on the soundboard is also given. There is
also reference to the soundboard of the Salvi "Electra" harp.
Chapter 4 deals with the air resonances in the enclosed air volume
of the "Orchestra" soundbox. Both a Helmholtzian air mode and higher
order air modes are discussed. Theoretical models are used for both
forms of air modes, Chapter 5 is a report of the vibrational modes of
the "Orchestra" soundbox using both Chladni glitter patterns and
holographic interferonietry. The results of Chapter 5 are confirmed and
expanded by the work in Chapter 6, where input admittance measurements
are made on the soundbox.Chapter 7 investigates the vibrational modes of
the soundbox, both in the isolated state and as part of a completed,
strung harp.
This is followed by a chapter on the directivity of the "Orchestra"
harp in which the principal areas of radiation from the harp are
reported. The next chapter deals with attempts to relate objective
measurements with subjective opinions of six concert harps. The last chapter summarises the principal results of the various
analyses reported in this thesis. Suggestions for further research on
the harp are made. There are also suggestions for the improvement of the
Salvi "Orchestra" harp.
There are three appendices at the end of this work. The first deals
with the testing of spruce samples intended for the soundboards of the
harps. The effect of the veneer is also discussed. The second appendix
deals with the production and physical properties of gut harp strings.
The third appendix describes the changes to the resonant modes of an
isolated soundbox produced by changing the shape of the straining and
cover bars of the soundboard
A common currency for the Americas?
No full textDollarization ; Banks and banking, Central - Latin America ; Gross domestic product ; Banks and banking, Central - Mexico
Dataset for the journal paper titled "Low-temperature polycrystalline silicon waveguides for low loss transmission in the near-to-mid-infrared region"
No full textThis dataset supports the publication: Amar N. Ghosh, Stuart J. MacFarquhar, Ozan Aktas, Than S. Saini, Swe Z. Oo, Harold M. H. Chong, and Anna C. Peacoc (2022)
Low-temperature polycrystalline silicon waveguides for low loss transmission in the near-to-mid-infrared region. Optics Express. The excel file contains all experimental data used for generating Fig.3 and Fig.6.</span
2D-SWE of the Metacarpophalangeal Joint Capsule in Horses
No full text(1) Two-dimensional shear wave elastography (2D-SWE) employs an ultrasound impulse to produce transversely oriented shear waves, which travel through the surrounding tissue according to the stiffness of the tissue itself. The study aimed to assess the reliability of 2D-SWE for evaluating the elastosonographic appearance of the distal attachment of the fetlock joint capsule (DJC) in sound horses and in horses with osteoarthritis (OA) (2). According to a thorough evaluation of metacarpophalangeal joint (MCPJ), adult horses were divided in a sound Group (H) and in OA Group (P). Thereafter, a 2D-SWE of MCPJs was performed. Shear wave velocity (m/sec) and Young’s modulus (kPa) were calculated independently by two operators at each selected ROI. Statistical analysis was performed with R software. (3) Results: 2D-SWE had good–excellent inter-CC and intra-CC in both groups. Differences in m/s and kPa between Groups H and P were found in transverse scans with lower values in Group P. No correlation with age or DJC thickness was found. (4) Conclusions: 2D-SWE was repeatable and reproducible. In Group H, DJC was statistically stiffer than in Group P only in transverse scan. The technique showed poor sensitivity and specificity in differentiating fetlocks affected by OA
Takayasu arteritinde karotis intima media elastikiyetinin SWE ile değerlendirilmesi
No full textThis study aimed to evaluate carotid morphology with Ultrasound (US) and arterial stiffness with Shear Wave Elastography (SWE) in TA patients and to compare results with disease activity. We searched the clinical archive and found 41 Takayasu Arteritis (TA) patients with carotid involvement had carotid US and SWE screening. Patients (n=22) with confounding factors that could affect the carotid wall were excluded. Nineteen cases that meet the inclusion criteria and 19 healthy control cases age-sex matched were compared. We evaluated right and left common carotid artery intima-media thickness (IMT) with B-Mode US and wall stiffness with SWE. We also investigated a relationship between disease activation and arterial stiffness. Carotid artery IMT was significantly higher in TA than in the control group (p<0.001). Median stiffness values for the carotid wall in TA were 28.3 kPa and 36.3 kPa on the right and left and in the control group 26.1 kPa and 28.1 kPa, respectively. The left CCA stiffness was significantly higher in the TA than in the control group (p=0.03), whereas the difference in right CCA elasticity did not reach statistical significance. A left CCA cut-off value of 52 kPa reached the highest accuracy with a specificity of 100% and a sensitivity of 36.8% in TA. No significant relationship was found between disease activation and elasticity value. SWE alone is not diagnostic but can be a useful adjunctive modality to gray-scale ultrasound in assessing carotid artery involvement with TA.Bu çalışmanın amacı Takayasu Arteriti (TA) hastalarında Ultrasonografi (US) ile karotis morfolojisini ve Shear Wave Elastografi (SWE) ile arteriyel sertliği değerlendirmek ve sonuçları hastalık aktivitesi ile karşılaştırmaktır. Klinik arşiv taranmış ve karotis tutulumu olan, karotis US ve SWE görüntülemesi yapılmış 41 TA hastası bulundu. Karotis duvarını etkileyebilecek kafa karıştırıcı faktörleri olan hastalar (n:22) çalışma dışı bırakıldı. Dahil edilme kriterlerini karşılayan 19 hasta ve yaş ve cinsiyet açısından benzer 19 sağlıklı kontrol olgusu karşılaştırıldı. B-Mode US ile sağ ve sol ana karotis arter intima-media kalınlığı (IMT) ve SWE ile duvar sertliği değerlendirildi. Ayrıca hastalık aktivasyonu ile arteriyel sertlik arasındaki ilişki de araştırıldı. Karotis arter İMK, TA'da kontrol grubuna kıyasla anlamlı derecede yüksek bulundu (p<0,001). Karotis duvarı için medyan sertlik değerleri TA'da sağ ve solda sırasıyla 28,3 kPa ve 36,3 kPa, kontrol grubunda ise 26,1 kPa ve 28,1 kPa idi. Sol CCA sertliği TA'da kontrol grubuna kıyasla anlamlı derecede yüksekken (p=0,03), sağ CCA sertliğinde anlamlı farklılık saptanmadı. TA'da 52 kPa'lık sol CCA cut-off değeri %100 özgüllük ve %36,8 duyarlılık ile en yüksek doğruluğa ulaşmıştır. Hastalık aktivasyonu ile elastikiyet değeri arasında anlamlı bir ilişki bulunmadı. SWE tek başına tanısal değildir, ancak karotis tutulumunu değerlendirmede B-Mode US'ye ek olarak yararlı bir yöntem olabilir
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