scholarly journals Comparison of CPU and GPU Bayesian Estimates of Fibre Orientations from Diffusion MRI

2019 ◽  
Author(s):  
Danny H.C. Kim ◽  
Lynne J. Williams ◽  
Moises Hernandez-Fernandez ◽  
Bruce H. Bjornson
Keyword(s):  
Diffusion Mri ◽  
Average Output ◽  
Whole Brain ◽  
Diffusion Parameters ◽  
Kolmogorov Smirnov ◽  
Multiple Trials ◽  
Gpu Algorithms ◽  
The Difference ◽  
Correct Estimation ◽  
Fibre Fraction

AbstractBackgroundThe correct estimation of fibre orientations is a crucial step for reconstructing human brain tracts. A popular and extensively used tool for this estimation is Bayesian Estimation of Diffusion Parameters Obtained using Sampling Techniques (bedpostx), which is able to estimate several fibre orientations per voxel (i.e. crossing fibres) using Markov Chain Monte Carlo (MCMC). However, for fitting a model in a whole diffusion MRI dataset, MCMC can take up to a day to complete on a standard CPU. Recently, this algorithm has been ported to run on GPUs, which can accelerate the process, completing the analysis in minutes or hours. However, few studies have looked at whether the results from the CPU and GPU algorithms differ. In this study, we compared CPU and GPU bedpostx outputs by running multiple trials of both algorithms on the same whole brain diffusion data and compared each distribution of output using Kolmogorov-Smirnov tests.ResultsWe show that distributions of fibre fraction parameters and principal diffusion direction angles from bedpostx and bedpostx_gpu display few statistically significant differences in shape and are localized sparsely throughout the whole brain. Average output differences are small in magnitude compared to underlying uncertainty.ConclusionsDespite small amount of differences in samples created between CPU and GPU bedpostx algorithms, results are comparable given the difference in operation order and library usage between CPU and GPU bedpostx.

Model for Epitaxial growth of Cobalt on CU(100)

1989 ◽  
Vol 160 ◽  
Author(s):  
Dimitri D. Vvedensky ◽  
Shaun Clarke
Keyword(s):  
Epitaxial Growth ◽  
Growth Kinetics ◽  
Solid Model ◽  
Free Energies ◽  
Diffusion Parameters ◽  
The Difference ◽  
Kinetics Of

AbstractThe epitaxial growth kinetics of Co on Cu(100) are investigated with a kinetic solid-on-solid model. Two effects are found to dominate the growth of this system reflecting the difference in surface free energies betweenthe two materials: the difference of diffusion parameters, and the inability of Co to wet Cu(100) at lower temperatures.

scholarly journals White-matter free-water diffusion MRI in schizophrenia: a systematic review and meta-analysis

2022 ◽  
Author(s):  
Inês Carreira Figueiredo ◽  
Faith Borgan ◽  
Ofer Pasternak ◽  
Federico E. Turkheimer ◽  
Oliver D. Howes
Keyword(s):  
White Matter ◽  
Healthy Volunteers ◽  
Diffusion Mri ◽  
Clinical Symptoms ◽  
Free Water ◽  
Brain Regions ◽  
Water Levels ◽  
First Episode ◽  
Whole Brain ◽  
Illness Duration

AbstractWhite-matter abnormalities, including increases in extracellular free-water, are implicated in the pathophysiology of schizophrenia. Recent advances in diffusion magnetic resonance imaging (MRI) enable free-water levels to be indexed. However, the brain levels in patients with schizophrenia have not yet been systematically investigated. We aimed to meta-analyse white-matter free-water levels in patients with schizophrenia compared to healthy volunteers. We performed a literature search in EMBASE, MEDLINE, and PsycINFO databases. Diffusion MRI studies reporting free-water in patients with schizophrenia compared to healthy controls were included. We investigated the effect of demographic variables, illness duration, chlorpromazine equivalents of antipsychotic medication, type of scanner, and clinical symptoms severity on free-water measures. Ten studies, including five of first episode of psychosis have investigated free-water levels in schizophrenia, with significantly higher levels reported in whole-brain and specific brain regions (including corona radiata, internal capsule, superior and inferior longitudinal fasciculus, cingulum bundle, and corpus callosum). Six studies, including a total of 614 participants met the inclusion criteria for quantitative analysis. Whole-brain free-water levels were significantly higher in patients relative to healthy volunteers (Hedge’s g = 0.38, 95% confidence interval (CI) 0.07–0.69, p = 0.02). Sex moderated this effect, such that smaller effects were seen in samples with more females (z = −2.54, p < 0.05), but antipsychotic dose, illness duration and symptom severity did not. Patients with schizophrenia have increased free-water compared to healthy volunteers. Future studies are necessary to determine the pathological sources of increased free-water, and its relationship with illness duration and severity.

PENGARUH KOMBINASI EKSTRAK JERUK BRASTAGI DAN WORTEL PER ORAL SEBELUM AKTIVITAS FISIK TERHADAP PENURUNAN KADAR MDA PLASMA MENCIT SETELAH AKTIVITAS FISIK

2017 ◽  
Vol 1 (1) ◽  
pp. 41
Author(s):  
Nurvidya Rachma Dewi ◽  
Ambrosius Purba ◽  
Beltasar Tarigan
Keyword(s):  
Physical Activity ◽  
Free Radicals ◽  
Cellular Level ◽  
Not Given ◽  
Time Intervals ◽  
Kolmogorov Smirnov ◽  
Group A ◽  
The Difference ◽  
Group B ◽  
Per Oral

Aerobic metabolism in the cellular level generates free radicals. Under normal condition,theres balance between free radicals and endogenous antioxidants. Excessive amount of freeradicals impair DNA, protein, fat, etc. The level of free radicals can be known by measuringplasma malondialdehyde level. Combination of Brastagis oranges and carrots juice asexogenous antioxidants supplementation expected to decrease free radicals level . The aim of thisstudy is to investigate the difference of plasma MDA level during several time intervals on micewhich is given and not given combination of Brastagis oranges and carrots juice before physicalactivity using mices treadmill for 20 minutes. The research method used in this study is anexperimental laboratory study. The objects of this study are 40 mice (mus musculus), whitecolored, male, weighting 25-30 grams, which is randomly chosen. The objects are divided into 2groups, Group A : 20 mice (given combination of Brastagis oranges and carrots juice beforephysical activity using mices treadmill) and group B : 20 mice (not given combination ofBrastagis oranges and carrots juice before physical activity using mices treadmill). Group Aare divided into 5 subgroups: A1 (measurement of plasma MDA level at 0 minute after treadmill),A2 (measurement of plasma MDA level at 15 minutes after treadmill), and A3 (measurement ofplasma MDA level at 30 minutes after treadmill), A4 (measurement of plasma MDA level at 60minutes after treadmill), and A5 (measurement of plasma MDA level at 240 minutes aftertreadmill). The same procedures are employed for the group B. Plasma MDA level measuredafter doing physical activity using mice treadmill. The homogenity of the result then was testedusing Levenes test and the normality of the result was tested using Kolmogorov-smirnov test (p>0.05). Further, the data was analyzed using independent t-test (p?0.05), one-way ANOVA(p?0.05) then Duncans test were used. The results reveal significant lowering plasma MDAconcentration in mice receiving combination of Brastagis oranges and carrots juice beforephysical activity, which is measured during several time intervals : 0,15,30,60, and 240 minutesafter physical activity than in mice not receiving combination of Brastagis oranges and carrotsjuice before physical activity. The MDA level differences between groups which is given and notgiven combination of Brastagis orange and carrots juice before physical activity measuredduring several intervals are 11,44% (0,8920 vs 1,0071) measured 0 minute after physical activity,15,47% (0,7902 vs 0,9348) measured 15 minutes after physical activity, 14,42% (0,7473 vs0,8732) measured 30 minutes after physical activity, 11,35% (0,6696 vs 0,7554) measured 60minutes after physical activity, and 13,60% (0,5786 vs 0,6696) measured 240 minutes afterphysical activity.The conclusion of the study suggested that combination of Brastagis orange andcarrots juice supplementation has lowering effect toward plasma MDA level measured duringseveral time intervals.

Abstract WP45: Comparison of Automated Whole Brain CT Perfusion Analysis with Perfusion-Diffusion MRI in Ischemic Stroke

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Bruce C Campbell ◽  
Søren Christensen ◽  
Nawaf Yassi ◽  
Gagan Sharma ◽  
Andrew Bivard ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Diffusion Mri ◽  
Ct Perfusion ◽  
Diffusion Imaging ◽  
Residue Function ◽  
Accurate Estimate ◽  
Mr Perfusion ◽  
Infarct Core ◽  
Whole Brain ◽  
Brain Ct

Background and purpose: CT perfusion (CTP) provides rapid and accessible imaging of ischemic stroke pathophysiology. Studies with limited brain coverage CTP have suggested that relative cerebral blood flow (relCBF) is the optimal CTP parameter to define irreversible infarction. We analyzed patients with whole brain CT perfusion and contemporaneous MR perfusion-diffusion imaging to confirm the optimal CTP parameter for infarct core and compare mismatch classification between MR and CT. Methods: Acute ischemic stroke patients <6hr after onset had whole brain CTP (320slice) closely followed by perfusion-diffusion MRI. Maps of CBF, CBV and time-to-peak of the deconvolved tissue residue function (Tmax) were generated by RAPID automated perfusion analysis software (Stanford University) using delay insensitive deconvolution. The optimal CTP map to identify infarct core was selected by maximizing the average Dice co-efficient across the same threshold range for all patients using co-registered diffusion lesion (manually outlined to its maximal visual extent) as reference region. Mismatch classification agreement between CT and MRI was then assessed using 2 definitions: mismatch ratio a) >1.2 or b) >1.8, absolute mismatch a) >10mL or b) >15mL, infarct core<70mL. Results: In 28 patients imaged <6hr from stroke onset (median age 69, median onset to CT 180min, median CT to MR 69min), relCBF provided the most accurate estimate for infarct core, significantly better than absolute or relative CBV (both p<0.001). Using relCBF to generate acute CTP infarct core volumes, the median magnitude of volume difference versus diffusion MR was 6.9mL, interquartile range 1.6-27.4mL. CTP mismatch between relCBF core and Tmax>6sec perfusion lesion was assessed in 25 patients (3/28 had no MR perfusion). CTP and MR perfusion-diffusion mismatch classification agreed in 23/25 (92%) patients (kappa 0.84) using either definition. Conclusions: This study using whole brain CTP confirms the greater accuracy of CBF over CBV for estimation of the infarct core. The >90% agreement in mismatch classification between CTP and MRI supports the concept that both modalities can identify similar patient populations for clinical trials of reperfusion therapies.

scholarly journals Indicadores de desempenho registrados em função do tempo no basquetebol brasileiro

2018 ◽  
Vol 20 (2) ◽  
pp. 172-181
Author(s):  
Yura Yuka Sato dos Santos ◽  
Lucas Antônio Monezi ◽  
Milton Shoiti Misuta ◽  
Luciano Allegretti Mercadante
Keyword(s):  
Performance Analysis ◽  
Normal Distribution ◽  
Professional Basketball ◽  
Technical Indicators ◽  
Point Field ◽  
Emerging Issues ◽  
Kolmogorov Smirnov ◽  
The Difference ◽  
The Moment ◽  
Smirnov Test

Basketball performance analysis using technical indicators dissociated from the moment they occurred in the game seems to no longer respond to emerging issues of the game as it does not identify the periods when a team’s offensive efficiency has increased or decreased. The aim was to characterize and compare the technical indicators in the positive and negative periods and in the whole game of winning and losing teams in men’s professional basketball. Fourteen games of professional men’s teams of the “Novo Basquete Brasil” Championship in the regular 2011/2012 season were filmed and analyzed. The Kolmogorov-Smirnov test was used to verify data normality. The independent T test was used for variables with normal distribution and the Mann-Whitney test for variables that did not present normal distribution, in order to compare teams’ performance. Analysis in the whole game showed that winning teams had significantly higher averages in successful 3-point field goals but in the positive periods, they showed higher averages for successful free throws, successful layups, defensive rebounds and defensive fouls, and in negative periods, losing teams made more defensive and offensive fouls. The teams’ performance in the whole game may not elucidate the determinant indicators for building the difference in the scoreboard. It is suggested that coaches should identify the periods of best and worst teams’ performance in the game and the indicators involved, preparing teams to overcome the negative periods and obtain more positive periods in the game. 

scholarly journals Dynamical Age Determination of Open Clusters

1980 ◽  
Vol 85 ◽  
pp. 221-222
Author(s):  
M. Buchholz ◽  
Th. Schmidt-Kaler
Keyword(s):  
Age Determination ◽  
Dynamical Theory ◽  
Distribution Functions ◽  
Open Clusters ◽  
Kolmogorov Smirnov ◽  
The Difference ◽  
Absolute Age ◽  
Image Position ◽  
Smirnov Test

The radial mass distribution (obtained by counting stars in strips) of the real cluster is compared successively to the distribution functions of a simulated cluster of 100 stars, each of which corresponds to a certain dynamical age, Tdyn, The value of Tdyn, belonging to the function most similar to the observed one is taken to be the dynamical age of the cluster. The radius is given in units of R1/2 (sphere containing half of the total mass); this unit is nearly time-independent. The difference between the distribution functions is measured by the maximum Δmax of the Kolmogorov-Smirnov test which is free from assumptions on the form of the distributions. The minimum in the plot Δmax vs Tdyn, indicates the age of the cluster. It is then converted into an absolute age, Tabs (in years), by The error due to the dynamical theory (limited number of distribution functions, etc.) is estimated at 12%, the error due to the uncertainty of diameter and mass of the cluster is about 30%. Unreliable results were obtained in case of strongly inhomogeneous reddening of the cluster. As an example, the plot of the test values for NGC 457 is given in Figure 1.

scholarly journals Effect of dust deposition on the performance of photovoltaic modules in Taxila, Pakistan

2017 ◽  
Vol 21 (2) ◽  
pp. 915-923 ◽  
Author(s):  
Hafiz Ali ◽  
Muhammad Zafar ◽  
Muhammad Bashir ◽  
Muhammad Nasir ◽  
Muzaffar Ali ◽  
...  
Keyword(s):  
Output Power ◽  
Photovoltaic Module ◽  
Strong Impact ◽  
Dust Deposition ◽  
Average Output ◽  
Photovoltaic Modules ◽  
Time Period ◽  
Different Types ◽  
The Difference ◽  
Module Efficiency

The air borne dust deposited on the surface of photovoltaic module influence the transmittance of solar radiations from the photovoltaic modules glazing surface. This experimental work aimed to investigate the effect of dust deposited on the surface of two different types of photovoltaic modules (monocrystalline silicon and polycrystalline silicon). Two modules of each type were used and one module from each pair was left exposed to natural atmosphere for three months of winter in Taxila, Pakistan. Systematic series of measurements were conducted for the time period of three months corresponding to the different dust densities. The difference between the output parameters of clean and dirty modules provided the information of percentage loss at different dust densities. The dust density deposited on the modules surface was 0.9867 mg/cm2 at the end of the study. The results showed that dust deposition has strong impact on the performance of photovoltaic modules. The monocrystalline and polycrystalline modules showed about 20% and 16% decrease of average output power, respectively, compared to the clean modules of same type. It was found that the reduction of module efficiency (?clean ? ?dirtv) in case of monocrystalline and polycrystalline module was 3.55% and 3.01%, respectively. Moreover the loss of output power and module efficiency in monocrystalline module was more compared to the polycrystalline module.

scholarly journals Age and Sex Related Changes in Weight of the Whole brain: a Postmortem Study

2014 ◽  
Vol 13 (4) ◽  
pp. 396-400
Author(s):  
Kanij Fatema ◽  
Shamim Ara ◽  
Mushfika Rahman ◽  
Halima Afroz
Keyword(s):  
Medical Science ◽  
Age Groups ◽  
Cross Sectional ◽  
Whole Brain ◽  
Male And Female ◽  
Adult Age ◽  
Group A ◽  
The Difference ◽  
Group D ◽  
The Brain

Objective: Brain weight varies with age and gender. It decreases with age and also in many diseases. This cross-sectional analytical type of study was carried out to establish normal standard in different age groups in weight of the brain and to see the difference between sexes of adult Bangladeshi people. Materials and Methods: A total of 70 postmortem human brains of adult age groups ranging from 22-58 years in male and 22-48 years in female were collected from the unclaimed dead bodies during postmortem at the autopsy laboratory in the Department of Forensic Medicine, Dhaka Medical College, Dhaka, from January 2010 to December 2010. The samples were divided into four different age groups i.e. Group A (20-29 years), Group B (30-39 years), Group C (40-49 years) and Group D (50-59 years). The weight of the whole brain was measured and significant differences in weight of the whole brain between different age groups and between male and female were determined.Results: In male highest value of weight was 1326.67±41.53 gm in group A and lowest one was 1281.6±40.21 gm in group D. These values of female were 1235.56±48.51 gm in group A and 1197.14±38.61 gm in group C. Significant differences were found in mean weight of the whole brain in male and female in group A (p=0.001), B (p=0.001) and C (p=0.001). The difference of mean weight in different age groups was not statistically significant. Conclusion: The weight of the brain is higher in male than in female and it decreases with age. DOI: http://dx.doi.org/10.3329/bjms.v13i4.20554 Bangladesh Journal of Medical Science Vol.13(4) 2014 p.396-400

scholarly journals Empirical Modeling of Layered Integrated Water Vapor Using Surface Mixing Ratio in Nigeria

2009 ◽  
Vol 48 (2) ◽  
pp. 369-380 ◽  
Author(s):  
B. Adeyemi
Keyword(s):  
Water Vapor ◽  
Empirical Modeling ◽  
Specific Humidity ◽  
Mixing Ratio ◽  
Coastal Station ◽  
Northern Regions ◽  
Surface Mixing ◽  
Kolmogorov Smirnov ◽  
The Difference ◽  
Upper Level

Abstract Using the available upper-air data for three stations in Nigeria (Lagos, a coastal station; Minna, an inland station; and Kano, a sub-Sahelian station), an intensive examination has been carried out on the linkage between surface mixing ratio rs and layered integrated water vapor W (g cm−2) over Nigeria. The goal was to identify the seasonal distribution of the parameter and to develop models that can best be used to estimate W from surface mixing ratio. To achieve these objectives, integrated water vapor at the low level (WL), midlevel (Wm), and upper level (Wu) and total column integrated water WT have been calculated using daily values of upper-air data spanning over a decade from the above three radiosonde stations. A relationship of the form W = αrs + β (where α and β are constants) has been established between W and rs using the analysis-of-variance (ANOVA) technique. Tests carried out on the models, using daily soundings made in 1990 for Lagos, 1983 for Minna, and 1991 for Kano, respectively, gave encouraging results as established by the use of Kolmogorov–Smirnov tests. Owing to the difference in the climatological patterns of precipitation among the different regions in Nigeria (i.e., southern, midland, and northern regions) as represented by the three stations, no single relationship was found to be suitable for the entire country of Nigeria. Earlier models, generally of the form W = αqb (where α and b are constants and q is specific humidity), were found to be less adequate over the stations.

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