Periventricular lucency evaluated by second-derivative finger plethysmography

The method of the geopotential parameters determination with the use of the gradiometry data is considered. The second derivative of the gravitational potential in the correction equation on the rectangular coordinates x, y, z is used as a measured variable. For the calculated value of the measured quantity required for the formation of a free member of the correction equation, the the Cunningham polynomials were used. We give algorithms for computing the second derivatives of the Cunningham polynomials on rectangular coordinates x, y, z, which allow to calculate the second derivatives of the geopotential at the rectangular coordinates x, y, z.Then we convert derivatives obtained from the Cartesian coordinate system in the coordinate system of the gradiometer, which allow to calculate the free term of the correction equation. Afterwards the correction equation coefficients are calculated by differentiating the formula for calculating the second derivative of the gravitational potential on the rectangular coordinates x, y, z. The result is a coefficient matrix of the correction equations and corrections vector of the free members of equations for each component of the tensor of the geopotential. As the number of conditional equations is much more than the number of the specified parameters, we go to the drawing up of the system of normal equations, from which solutions we determine the required corrections to the harmonic coefficients.

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A nonlinear second derivative method with a variable step-size based on continued fractions for singular initial value problems

Cogent Mathematics ◽

10.1080/23311835.2017.1335498 ◽

2017 ◽

Vol 4 (1) ◽

pp. 1335498 ◽

Cited By ~ 1

Author(s):

S.N. Jator ◽

N. Coleman ◽

Nikos Katzourakis

Keyword(s):

Continued Fractions ◽

Initial Value Problems ◽

Variable Step Size ◽

Second Derivative ◽

Initial Value ◽

Step Size ◽

Derivative Method ◽

Variable Step ◽

Second Derivative Method

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Simultaneous determination of polymetallic ions by ratio second derivative ultraviolet spectrophotometry

Optik ◽

10.1016/j.ijleo.2021.167315 ◽

2021 ◽

pp. 167315

Author(s):

Fengbo Zhou ◽

Shaojie Wang ◽

Hongqiu Zhu ◽

Changgeng Li

Keyword(s):

Simultaneous Determination ◽

Second Derivative ◽

Ultraviolet Spectrophotometry

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Orbital Stability of Solitary Waves to Double Dispersion Equations with Combined Power-Type Nonlinearity

Mathematics ◽

10.3390/math9121398 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1398

Author(s):

Natalia Kolkovska ◽

Milena Dimova ◽

Nikolai Kutev

Keyword(s):

Solitary Waves ◽

Orbital Stability ◽

Second Derivative ◽

Cubic Nonlinearity ◽

Abstract Theory ◽

Power Type ◽

Analytical Formulas ◽

Stability Of Solitary Waves ◽

The Stability ◽

Double Dispersion

We consider the orbital stability of solitary waves to the double dispersion equation utt−uxx+h1uxxxx−h2uttxx+f(u)xx=0,h1>0,h2>0 with combined power-type nonlinearity f(u)=a|u|pu+b|u|2pu,p>0,a∈R,b∈R,b≠0. The stability of solitary waves with velocity c, c2<1 is proved by means of the Grillakis, Shatah, and Strauss abstract theory and the convexity of the function d(c), related to some conservation laws. We derive explicit analytical formulas for the function d(c) and its second derivative for quadratic-cubic nonlinearity f(u)=au2+bu3 and parameters b>0, c2∈0,min1,h1h2. As a consequence, the orbital stability of solitary waves is analyzed depending on the parameters of the problem. Well-known results are generalized in the case of a single cubic nonlinearity f(u)=bu3.

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Research on Optimal Algorithm for Time-domain Synthesis of Shock Response Spectrum Based on Continuous Second Derivative

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/632/3/032039 ◽

2021 ◽

Vol 632 ◽

pp. 032039

Author(s):

Wei Song ◽

Ru Wang ◽

Pengting Lin ◽

Mi Liu ◽

Jianchao Wu ◽

...

Keyword(s):

Time Domain ◽

Optimal Algorithm ◽

Response Spectrum ◽

Second Derivative ◽

Shock Response ◽

Shock Response Spectrum

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Comparison of the finger plethysmography derived stroke volumes by Nexfin CO Trek and suprasternal aortic Doppler derived stroke volume measurements in adults with myalgic encephalomyelitis/chronic fatigue syndrome and in healthy controls

Technology and Health Care ◽

10.3233/thc-202669 ◽

2021 ◽

pp. 1-14

Author(s):

C. (Linda) M.C. van Campen ◽

Freek W.A. Verheugt ◽

Peter C. Rowe ◽

Frans C. Visser

Keyword(s):

Chronic Fatigue Syndrome ◽

Stroke Volume ◽

Chronic Fatigue ◽

Calibration Procedure ◽

Myalgic Encephalomyelitis ◽

Tilt Test ◽

Healthy Controls ◽

Tilt Testing ◽

Fatigue Syndrome ◽

Finger Plethysmography

BACKGROUND: Finger plethysmography derived stroke volumes are frequently measured during tilt table testing. There are two algorithms to determine stroke volumes: Modelflow and NexfinCO Trek. Most tilt studies used Modelflow, while there are differences between the two algorithms. OBJECTIVE: To compare stroke volume indices by Nexfin CO Trek (SVINexfinCOTrek) with suprasternal Doppler derived SVI (SVIDoppler) in healthy controls (HC) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients during tilt testing. These patients may have a large SVI decrease during the tilt enabling a large range of SVI to be studied. METHODS: One hundred and fifty-four patients and 39 HC with a normal tilt test were included. Supine and end-tilt SVIDoppler and SVINexfinCOTrek were compared using the Bland-Altman analysis. Also, the effect of calibrating supine SVINexfinCOTrek to SVIDoppler was studied RESULTS: Supine and end-tilt SVINexfinCOTrek were significantly higher than SVIDoppler: both P< 0.005. Bias, limits of agreement, and percent error (PE) were high with PE’s between 37 and 43%. The calibration procedure resulted in an acceptable variance with a PE of 29%. CONCLUSIONS: SVINexfinCOTrek overestimates stroke volumes compared to SVIDoppler, leading to high PE’s. Calibration reduced variance to an acceptable level, allowing SVINexfinCOTrek to be used for assessment of SVI changes during tilt testing

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Second derivative synchronous fluorescence determination of avanafil in the presence of its acid-induced degradation product aided by powerful Lean Six Sigma tools augmented with D-optimal design

RSC Advances ◽

10.1039/d0ra08216c ◽

2021 ◽

Vol 11 (7) ◽

pp. 3834-3842

Author(s):

Khalid A. M. Attia ◽

Ahmad A. Mohamad ◽

Mohamed S. Emara ◽

Ahmed M. Abdel-Raoof ◽

Mohamed A. Hasan ◽

...

Keyword(s):

Optimal Design ◽

Quantitative Determination ◽

Degradation Product ◽

Six Sigma ◽

Lean Six Sigma ◽

Synchronous Fluorescence ◽

Second Derivative ◽

Fluorescence Determination ◽

Spectrofluorimetric Method

In this work, the quantitative determination of an erectile dysfunctional drug avanafil in the presence of its acid-induced degradation product was achieved via the application of a pre-optimized novel spectrofluorimetric method.

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Carboxyhemoglobin determination by second-derivative spectroscopy.

Clinical Chemistry ◽

10.1093/clinchem/31.2.279 ◽

1985 ◽

Vol 31 (2) ◽

pp. 279-281 ◽

Cited By ~ 17

Author(s):

J Parks ◽

H G Worth

Keyword(s):

Spectrum Analysis ◽

Spectral Shift ◽

Zero Order ◽

Reduced Form ◽

Second Derivative ◽

Derivative Spectrum ◽

Derivative Spectroscopy ◽

Set Up ◽

Second Derivative Spectroscopy

Abstract In this procedure hemoglobin is converted to its reduced form and the magnitude of the zero-order spectral shift of the reduced hemoglobin peak at 430 nm to the carboxyhemoglobin peak at 418 nm is determined by second-derivative spectrum analysis. The method is simple, straightforward to set up, and rapid. A result may be obtained within 15 min of receiving the sample. It is sufficiently sensitive to differentiate carboxyhemoglobin concentration in the blood of smokers and nonsmokers.

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