Second-degree Polynomial Research Articles

Optimization of the organic compounds synthesis

The paper presents the optimization of the geraniol transformation process based on the RSM method (response surface methodology). RSM is a fusion of statistical and mathematical modeling methods and explores the relationships between several explanatory variables and one or more response variables. The interaction among process variables can be determined by statistical techniques. It can be utilized in multi-criteria optimization. The influence of the most important process parameters, such as temperature, catalyst concentration and reaction time, is shown. The response functions characterizing the process were: conversion of geraniol, selectivity of thunbergol and selectivity of 6,11-dimethyl-2,6,10-dodecatrien-1-ol. For individual process parameters, their influence on all initial parameters in the form of second-degree polynomials was determined and such as process conditions were determined to achieve their maximum.

Regularized ridge regression models to estimate static elastic moduli from wireline measurements: case study from Southern Iraq

Elastic moduli such as Young’s modulus (E), Poisson’s ratio (v), and bulk modulus (K) are vital to creating geomechanical models for wellbore stability, hydraulic fracturing, sand production, etc. Due to the difficulty of obtaining core samples and performing rock testing, alternatively, wireline measurements can be used to estimate dynamic moduli. However, dynamic moduli are significantly different from elastic moduli due to many factors. In this paper, correlations for three zones (Nahr Umr shale, Zubair shale, and Zubair sandstone) located in southern Iraq were created to estimate static E, K, and ν from dynamic data. Core plugs from the aforementioned three zones alongside wireline measurements for the same sections were acquired. Single-stage triaxial (SST) tests with CT scans were executed for the core plugs. The data were separated into two parts; training (70%), and testing (30%) to ensure the models can be generalized to new data. Regularized ridge regression models were created to estimate static E, K, and ν from dynamic data (wireline measurements). The shrinkage parameter (α) was selected for each model based on an iterative process, where the goal is to ensure having the smallest error. The results showed that all models had testing R2 ranging between 0.92 and 0.997 and consistent with the training results. All models of E, K, and ν were linear besides ν for the Zubair sandstone and shale which were second-degree polynomial. Furthermore, root means squared error (RMSE) and mean absolute error (MAE) were utilized to assess the error of the models. Both RMSE and MAE were consistently low in training and testing without a large discrepancy. Thus, with the regularization of ridge regression and consistent low error during the training and testing, it can be concluded that the proposed models can be generalized to new data and no overfitting can be observed. The proposed models for Nahr Umr shale, Zubair shale, and Zubair sandstone can be utilized to estimate E, K, and ν based on readily available dynamic data which can contribute to creating robust geomechanical models for hydraulic fracturing, sand production, wellbore stability, etc.

Conics in Place

A method is presented for creating a problem, solving it, and confirming that the solution is correct. The problem is to analyze a second-degree polynomial equation in two variables, in order to identify and draw the defined conic section, with its axes, without changing coordinates. One creates the problemby choosing conjugate diameters that are not axes.

Enantioselective UHPLC Screening Combined with In Silico Modeling for Streamlined Development of Ultrafast Enantiopurity Assays.

Enantioselective chromatography has been the preferred technique for the determination of enantiomeric excess across academia and industry. Although sequential multicolumn enantioselective supercritical fluid chromatography screenings are widespread, access to automated ultra-high-performance liquid chromatography (UHPLC) platforms using state-of-the-art small particle size chiral stationary phases (CSPs) is an underdeveloped area. Herein, we introduce a multicolumn UHPLC screening workflow capable of combining 14 columns (packed with sub-2 μm fully porous and sub-3 μm superficially porous particles) with nine mobile phase eluent choices. This automated setup operates under a vast selection of reversed-phase liquid chromatography, hydrophilic interaction liquid chromatography, polar-organic mode, and polar-ionic mode conditions with minimal manual intervention and high success rate. Examples of highly efficient enantioseparations are illustrated from the integration of chiral screening conditions and computer-assisted modeling. Furthermore, we describe the nuances of in silico method development for chiral separations via second-degree polynomial regression fit using LC simulator (ACD/Labs) software. The retention models were found to be very accurate for chiral resolution of single and multicomponent mixtures of enantiomeric species across different types of CSPs, with differences between experimental and simulated retention times of less than 0.5%. Finally, we illustrate how this approach lays the foundation for a streamlined development of ultrafast enantioseparations applied to high-throughput enantiopurity analysis and its use in the second dimension of two-dimensional liquid chromatography experiments.

Estimation of lactation curves of Gyr cattle and some associated production parameters in the Colombian low tropic

Background: The Gyr breed is widely used in Colombian low tropic dairy production systems. During the last 10 years, the Asociación Colombiana de Criadores de Ganado Cebú† - ASOCEBU, has been leading a dairy milk control program which led to the creation of a dataset that permits to carry out the first analysis of milk yield in Gyr cattle in the country using records from several herds. Objectives: To study milk production dynamics of Gyr cattle in the Colombian low tropic through the estimation of lactation curves and four derived production parameters: total milk yield between 5 and 305 days (TMY305), peak milk yield (PMY), days at peak (DP) and persistency (P). Methods: 13,798 daily milk yield records from 1,510 cows performing in 103 herds were used; the total number of lactations was 2,480. Four models were considered: Wood, Wiltmink, Papajcsik & Bordero, and a second-degree polynomial. Mean square error, mean absolute error, mean square error of prediction, Akaike and Bayesian information criteria were used to select the model better describing each lactation using the majority rule, that is, the model selected by most criteria was the chosen one. The shape of each fitted lactation curve was checked using basic results from calculus which permitted the classification of the estimated curves into two groups: typical and atypical; only typical functions were used to compute the four aforementioned production parameters. Results: The second-order polynomial was the model most frequently selected, while the Papajcsik & Bordero model had the lowest frequency. Average TMY305, PMY, DP and P were 3,489.86 kg, 17.28 kg, 57.17 days, and 0.83, respectively, with coefficients of variation: 0.27, 0.21, 0.41, and 0.16. Conclusions: This study permitted to identify individuals with outstanding phenotypic performance. To the best of our knowledge, this is the first study of this kind involving thousands of lactations from Gyr cows performing in several regions of Colombian low tropic.

Optimization of Panax notoginseng root extract hydrolysis by Cordyceps militaris derived glycosidase and bioactivities of hydrolysis products

Ginsenosides are saponins found in plants of panax genus. Despite having a wide range of health benefits, they cannot optimally reach their target tissues and organs due to their low intestinal absorption. However, reduction of their sugar moieties can produce more absorbable and bioactive compounds. Even though they are known as a good source of glycosidase, edible and medicinal mushrooms are less investigated for their capability to hydrolyse ginsenosides. An enzyme from Cordyceps militaris was used to convert ginsenosides from Panax notoginseng roots. Response surface methodology was used to study the effect of temperature (30 – 60 °C), pH (6 – 7), time (30–80 h) and enzyme concentration (0.5 – 1%), on minor ginsenoside production and optimum conditions for maximum ginsenoside hydrolysis. Regression analysis was used to develop a second-degree polynomial model for the production of minor ginsenosides. Statistical significance of the model was evidenced by coefficient of determination (R2 = 95.15%) and (P value = 0.000). Minor ginsenosides production was affected by enzyme concentration, temperature and time respectively in order of magnitude. The effect of pH was found insignificant. Maximal minor ginsenosides were found at 0.86% enzyme concentration, 42.88 °C, 62.63 h and pH 6.62. A significant difference between hydrolysates from different treatments was observed for DPPH scavenging activity and antimicrobial activity. Hydrolysates have shown a strong cytotoxic activity against (SK-LU-1) and (MCF-7) cell lines. The model developed for Panax notoginseng hydrolysis by C. militaris derived glycosidase can potentially be used for producing minor ginsenosides with improved bioactivities for use in the production of food and medicines.

The effect of different dietary protein levels on growth performance and nutrient utilization of snarpsnout sea bream ( Diplodus puntazzo )

This study evaluated the effects of different dietary protein levels on growth performance and nutrient utilization of snarpsnout sea bream (Diplodus puntazzo) juveniles. Five isoenergetic diets were formulated to contain a dietary protein level at 30% (P30), 35% (P35), 40% (P40), 45% (P45) and 50% (P50). Each diet was randomly assigned to triplicate groups of fish (IBW 2.80 g) and fed to apparent satiation for 100 days. The dietary protein to energy ratio significantly affected the feed intake with the lower ratios leading to a higher feed consumption. The growth performance of D. puntazzo was gradually increased as the dietary protein level increased up to 40% and then gradually reduced as the dietary protein increased further to 45% and 50%. The feed efficiency got improved as dietary protein levels increased up to 45% but slightly decreased at 50% protein level. A second-degree polynomial regression analysis estimated that a dietary protein level at 41.4% and 43.8% delivered the maximum weight gain and the higher feed efficiency, respectively. The increased dietary carbohydrate and lipid levels in fish fed a low protein diet (P30) resulted in a significant deterioration of feed conversion and growth rates showing also reduced nutrient retentions and causing severe mortalities.

A geometric morphometric approach to investigate primate proximal phalanx diaphysis shape.

Current approaches to quantify phalangeal curvature assume that the long axis of the bone's diaphysis approximates the shape of a portion of a circle (included angle method) or a parabola (second-degree polynomial method). Here we developed, tested, and employed an alternative geometric morphometrics-based approach to quantify diaphysis shape of proximal phalanges in humans, apes and monkeys with diverse locomotor behaviors. 100 landmarks of the central longitudinal axis were extracted from 3D surface models and analyzed using 2DGM methods, including Generalized Procrustes Analyses. Principal components analyses were performed and PC1 scores (>80% of variation) represented the dorsopalmar shape of the bone's central longitudinal axis and separated taxa consistently and in accord with known locomotor behavioral profiles. The most suspensory taxa, including orangutans, hylobatids and spider monkeys, had significantly lower PC1 scores reflecting the greatest amounts of phalangeal curvature. In contrast, bipedal humans and the quadrupedal cercopithecoid monkeys sampled (baboons, proboscis monkeys) exhibited significantly higher PC1 scores reflecting flatter phalanges. African ape (gorillas, chimpanzees and bonobos) phalanges fell between these two extremes and were not significantly different from each other. PC1 scores were significantly correlated with both included angle and the a coefficient of a second-degree polynomial calculated from the same landmark dataset, but had a significantly higher correlation with included angles. Our alternative approach for quantifying diaphysis shape of proximal phalanges to investigate dorsopalmar curvature is replicable and does not assume a priori either a circle or parabola model of shape, making it an attractive alternative compared with existing methodologies.

Оцінка молекулярної мішені адемолу методом хемоінформатики

Актуальність. Глутаматна ексайтотоксичність та внутрішньочерепна гіпертензія являють собою потенційні мішені щодо можливих розробок патогенетичної терапії уражень мозку, зокрема тих, що асоційовані з високими значеннями внутрішньочерепного тиску. Мета. Методами хемоінформатики обґрунтувати внутрішньовенне застосування адемолу, виявити здатність адемолу блокувати β-адренорецептори, а також за критеріями лікоподібності та біодоступності оцінити можливість його проходження через гематоенцефалічний бар’єр (ГЕБ). Матеріали та методи. Всі обчислення молекулярних дескрипторів були зроблені за допомогою програмного комплексу SIB Swiss Institute of Bioinformatics, розрахункової платформи та Molinspiration Cheminformatics v2016.09, доступних on-line. Результати. Молекулярна маса адемолу не перевищує 500, середній показник ліпофільності розрахований за допомогою програмного комплексу [5], знаходиться для наведених сполук у прийнятному діапазоні. Для адемолу величина LogP дорівнює 2,736, що вище, ніж у ремантадину (2,456), однак нижче, ніж у пропранололу (2,967). Визначено загальну площу полярних поверхонь молекул (TPSA), що розраховується на основі методики, опублікованої Ertl et al. [6] у вигляді внесків суми площин атомів О та N та інших, у складі функціональних груп полярних фрагментів. Для предикації проникнення адемолу через ГЕБ використали розраховані in silico дескриптори — усереднену ліпофільність, що виявилася близькою до описаного раніше коефіцієнту ліпофільності у суміші октанолу та фосфатного буфера [9], та TPSA. Кореляція афінітету (LogKi, nM) з полярністю для відомих β-адреноблокаторів та адемолу описується як параболічна поліноміальна функція другого порядку. Висновки. Побудовано модель кореляції афінітету від ліпофільності для ряду β-адреноблокаторів та передбачено афінність адемолу, що наближається до високоафінних неселективних β-адреноблокаторів.

Novel Approach for Design of Merging and Diverging Length at Toll Plazas: A Case Study

Traffic operations at toll plazas are influenced by the merging and diverging behavior of vehicles near the toll plaza in the flare area. Proper guidelines for the design of merging and diverging sections at toll plazas under mixed traffic conditions are not specified by the Indian Highway Capacity Manual, the Indian Road Congress, or the American Association of State Highway and Transportation Officials. Thus, the present study attempts to develop design criteria for diverging and merging lengths. The field data were collected using the performance-box instrument at Ghoti toll plaza located at National Highway No. 60 in India, operating under mixed traffic conditions. The concept of discretization of speed profile is proposed and applied to segregate sections of the zone of influence into ten equal parts each of 50 m length. The statistical test shows that speed has a significant difference between the sections and also in between the different classes of vehicle. Results of the speed-distance plot show that the second-degree polynomial function is the best fit for zone of deceleration and power function for the zone of acceleration. The study revealed that, for 50 km/h approach speed, the minimum diverging and merging distances should be 125.67–308.98 m and 47.93–294.23 m, respectively. The proposed guidelines for merging and diverging length are useful for the design of the flare area and to improve operational efficiency and level of service at toll plazas operating under mixed traffic conditions.

Optimizing treatment goals for long-term health outcomes among patients with type 2 diabetes mellitus

IntroductionConsiderable confusions on treatment target have resulted from recent changes in guidelines. Evidence in medical guidelines came from clinical trials with highly selected patients, whereas treatment goals may differ in...

Numerical Analysis of Additional Stresses in Railway Track Elements Due to Subgrade Settlement Using FEM Simulation

The prediction of additional stresses in ballasted track due to subgrade deformation is the main objective of the present paper. In this context, a 2D finite element model of ballasted railway track was built using the ANSYS Workbench program. Based on this model, an investigation of stresses and deformation values of track elements was conducted in three cases with different contact types. It was found that the case introducing the status of a new track, which has frictional contacts between sleepers and ballast with bonded contacts between other elements, has lower stresses in most of the track elements. Moreover, this case was applied for studying the effect of the settlement on track elements. It was found that stresses increased with increasing the settlement value. The average percentages of increased stresses are 4.18%, 5.85%, and 7.21% in railhead, tie plate, and sleeper, respectively, due to a 1 mm increase in the settlement. Finally, a second-degree polynomial equation was derived to predict the additional stresses in each element due to track settlement. It is expected that this study would help to decrease the maintenance costs and extend the service life of the track elements by predicting the additional stresses in them.

PH and H2S Dual-Responsive Magnetic Metal-Organic Frameworks for Controlling the Release of 5-Fluorouracil.

Along with the increasing cancer incidence, developing suitable drug delivery systems (DDSs) is becoming urgent to control drug release and further enhance therapeutic efficiency. Herein, a Fe-Zn bimetallic MOF-derived ferromagnetic nanomaterial was synthesized by a one-step method. The successful preparation of ferromagnetic Fe-ZIF-8 was verified by scanning electron microscopy, powder X-ray diffraction, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy, and physical property measurement system characterizations. Furthermore, the release behaviors of 5-FU from the ferromagnetic carrier were investigated in a simulative cancer microenvironment of PBS buffer solution (PBS = phosphate-buffered saline, pH = 5.8) and NaHS solution. The vehicle in PBS solution of pH = 5.8 and NaHS solution of 500 μM can rapidly release 5-FU with the cumulative release percentages of 68 and 36%, respectively, within two hundred minutes. The release mechanism in the weak acid environment can be mainly attributed to the decomposition of the Fe-ZIF-8. However, the strong interaction between Zn and Fe atoms in Fe-ZIF-8 and the S atom in H2S plays an important role in the release process in the simulated H2S cancer microenvironment. The investigation of release kinetic models indicates that the 5-FU release in the PBS solutions and NaHS solution of 500 μM can be accurately fitted by a second-degree polynomial model and first-order model, respectively. In addition, the decomposition products, zinc, iron, and 2-MeIM, are endogenous and show low toxicity values [LD50 (Zn) = 0.35 g·kg-1, LD50 (Fe) = 30 g·kg-1, and LD50 (2-MeIM) = 1.4 g·kg-1]. Therefore, the low-toxicity, pH and H2S dual-stimuli-responsive, and ferromagnetic nature make the obtained Fe-ZIF-8 an ideal candidate in the field of bioactive molecule delivery.

Culture salinity modulates Nrf2 antioxidant signaling pathway and immune response of juvenile Genetically Improved Farmed Tilapia (GIFT) (Oreochromis niloticus) under different dietary protein levels

This study aimed to evaluate that dietary protein levels and culture salinity levels affect the health status of juvenile genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Graded protein levels of six diets were prepared, ranging from 18.20% to 49.49% (dry basis), and were used in cultured GIFT at two salinity levels (0‰ and 8‰) for 8 weeks. The results suggested that appropriate protein levels reduced pro-inflammatory gene expressions in the intestine including interleukin 1β (IL-1β), interleukin 8 (IL-8) and tumour necrosis factor-α (TNF-α) mRNA levels at two salinity levels (P < 0.05). 8‰ salinity significantly decreased the expression levels of IL-1β, TNF-α and nuclear factor-kappa B (NF-κB) (P < 0.05). The anti-inflammatory factor interleukin 10 (IL-10) was significantly increased by 36.42% protein level (P < 0.05). Regarding antioxidant capacity, appropriate protein levels and 8‰ salinity significantly improved the antioxidant capacity of fish by regulating the activities of intestinal total superoxide dismutase (T-SOD), glutathione peroxidase (GPx), and the levels of glutathione (GSH) and malondialdehyde (MDA). Furthermore, appropriate protein levels and 8‰ salinity also significantly enhanced the antioxidant gene expressions associated with the Nrf2/keap1 signaling pathway by regulating the expression levels of heme oxygenase-1 (HO-1), GPx, catalase (CAT) and superoxide dismutase (SOD). According to GPx activities and the mRNA levels of IL-10, the optimum dietary protein levels for GIFT juveniles were 31.12%–32.18% (0‰) and 34.25–35.38% (8‰) based on second-degree polynomial regression analysis. The present study found that appropriate protein levels and 8‰ culture salinity are critical in maintaining the health of GIFT juveniles by improving antioxidant and immune capacity.

Solution of the System of Two Coupled First-Order ODEs with Second-Degree Polynomial Right-Hand Sides

The explicit solution x n t , $x_{n}\left (t\right ) ,$ n = 1,2, of the initial-values problem is exhibited of a subclass of the autonomous system of 2 coupled first-order ODEs with second-degree polynomial right-hand sides, hence featuring 12 a priori arbitrary (time-independent) coefficients: x ̇ n = c n 1 x 1 2 + c n 2 x 1 x 2 + c n 3 x 2 2 + c n 4 x 1 + c n 5 x 2 + c n 6 , n = 1 , 2 . $$ \dot{x}_{n}=c_{n1}\left( x_{1}\right)^{2}+c_{n2}x_{1}x_{2}+c_{n3}\left( x_{2}\right)^{2}+c_{n4}x_{1}+c_{n5}x_{2}+c_{n6}~,~~~n=1,2~. $$ The solution is explicitly provided if the 12 coefficients cnj (n = 1,2; j = 1,2,3,4,5,6) are expressed by explicitly provided formulas in terms of 10 a priori arbitrary parameters; the inverse problem to express these 10 parameters in terms of the 12 coefficients cnj is also explicitly solved, but it is found to imply—as it were, a posteriori—that the 12 coefficients cnj must then satisfy 4 algebraic constraints, which are explicitly exhibited. Special subcases are also identified the general solutions of which are completely periodic with a period independent of the initial data (“isochrony”), or are characterized by additional restrictions on the coefficients cnj which identify particularly interesting models.

Two-dimensional spatial distribution modeling of sprinkler irrigation

Irrigation can provide significant agronomic and financial returns on agricultural activity. The maximization of the benefits obtained from irrigation depends, among other factors, on the water use efficiency, which is intrinsically related to application uniformity. For the sprinkler method, the irrigation uniformity assessment is based on results of labor-intensive field tests in which the two-dimensional water distribution pattern is measured in a grid of catch cans. The aim of this study was to evaluate a simplified methodology for determining the irrigation uniformity using water depth distribution data of a single sprinkler head in operation, positioned at the intersection of two diagonal alignments containing regularly spaced catch cans. Three methods to simulate the spatial water distribution on the alignments were evaluated: linear interpolation (LI), cubic spline (SC) and second-degree polynomial regression (PR). Each of these methods were associated with a procedure to calculate the two-dimensional spatial water distribution. The adequacy of the LI and SC modeling methods was verified by using the Wilcoxon-Mann-Whitney test (p-value < 0.05) applied to the data of the field tests. Mean values of the coefficient of efficiency equals to 0.771 and 0.785 were obtained for the LI and SC methods, respectively. The PR method underperformed the others.

SELECTION AND JUSTIFICATION OF THE MATHEMATICAL 6 FACTORS EXPERIMENT PLAN IN THE STUDY OF ICE STARTING QUALITIES

The practical significance of the application of multivariate regression analysis in engineering practice as a necessary step towards improving and optimizing complex systems and processes is presented. The goal and investigation tasks have been actualized to optimize the start-up process of a high-speed subcompact diesel engine. Preparation of the plural factors experiment features of diesel start-up process based on regression analysis and the theory of mathematical design of experiment are presented. Qualitative optimizing parameters of the diesel engine cold start are determined: instantaneous acceleration of the crankshaft dn / dτ at the time of crankshaft cranking by an external energy source close to the time spent on starting the engine with optimal parameters of the starting system and starting energy consumed during the crankshaft cranking by an external energy source. Six main factors influence on certain parameters of the diesel engine start quality have been investigated. The regression equation for assessing the quality of the start-up process is substantiated. The form of regression equation is a full quadratic polynomial for the reproduction of the investigated functions, based on the previous study of some used in the study individual factors influence. The analysis of proposals for rational plan selection of a six-factor experiment to find the coefficients of the second-degree regression polynomial is carried out. The substantiation of the decision regarding the choice of the plan is given. Selection was based on the requirements of the investigation test bench and the conditions for study organizing. Main impact had the predecessors experience of similar investigation and the statistical criteria for different plans of experiment comparison used in mathematical theory of design of experiments. The points of the plan have been defined on a multidimensional cube due to the need to vary on three levels with a uniform step of all 6 factors that were identified as influential. Under the conditions of the available laboratory test bench, the current values of the factors of equivalent cold start temperature, crankshaft-cranking speed and maximum temperature of the glow plugs have a variance of the installation at different points of the plan, and the nature of the factors on energy consumption is unknown in advance. As a rational experimental design for organizing the current study, the Box-Wilson orthogonal central compositional plan was chosen, built by adding plan points on the axes of the factorial space to the full-factorial plan of the lowest order, while maintaining the requirement of orthogonality and symmetry of the plan.

Internal Variability Role on Estimating Sea Level Acceleration in Fremantle Tide Gauge Station

Low frequency internal signals bring challenges to signify the role of anthropogenic factors in sea level rise and to attain a certain accuracy in trend and acceleration estimations. Due to both spatially and temporally poor coverage of the relevant data sets, identification of internal variability patterns is not straightforward. In this study, the identification and the role of low frequency internal variability (decadal and multidecadal) in sea level change of Fremantle tide gauge station is analyzed using two climate indices, Pacific Decadal Oscillation (PDO) and Tripole Interdecadal Pacific Oscillation (TPI). It is shown that the multidecadal sea level variability is anticorrelated with corresponding components of climate indices in the Pacific Ocean, with correlation coefficients of −0.9 and −0.76 for TPI and PDO, respectively. The correlations are comparatively low on decadal time scale, −0.5 for both indices. This shows that internal variability on decadal and multidecadal scales affects the sea level variation in Fremantle unequally and thus, separate terms are required in trajectory models. To estimate trend and acceleration in Fremantle, three trajectory models are tested. The first model is a simple second-degree polynomial comprising trend and acceleration terms. Low passed PDO, representing decadal and interdecadal variabilities in Pacific Ocean, added to the first model to form the second model. For the third model, decomposed signals of decadal and multidecadal variability of TPI are added to the first model. In overall, TPI represents the low frequency internal variability slightly better than PDO for sea level variation in Fremantle. Although the estimated trends do not change significantly, the estimated accelerations varies for the three models. The accelerations estimated from the first and second models are statistically insignificant, 0.006 ± 0.012 mm yr−2 and 0.01 ± 0.01 mm yr−2, respectively, while this figure for the third model is 0.018 ± 0.011 mm yr−2. The outcome exemplifies the importance of modelling low frequency internal variability in acceleration estimations for sea level rise in regional scale.

Directionally dependent Lambertian-equivalent reflectivity (DLER) of the Earth's surface measured by the GOME-2 satellite instruments

Abstract. In this paper we introduce the new concept of directionally dependent Lambertian-equivalent reflectivity (DLER) of the Earth's surface retrieved from satellite observations. This surface DLER describes Lambertian (isotropic) surface reflection which is extended with a dependence on the satellite viewing geometry. We apply this concept to data of the GOME-2 satellite instruments to create a global database of the reflectivity of the Earth's surface, providing surface DLER for 26 wavelength bands between 328 and 772 nm as a function of the satellite viewing angle via a second-degree polynomial parameterisation. The resolution of the database grid is 0.25∘ by 0.25∘, but the real, intrinsic spatial resolution varies over the grid from 1.0∘ by 1.0∘ to 0.5∘ by 0.5∘ down to 0.25∘ by 0.25∘ by applying dynamic gridding techniques. The database is based on more than 10 years (2007–2018) of GOME-2 data from the MetOp-A and MetOp-B satellites. The relation between DLER and bi-directional reflectance distribution function (BRDF) surface reflectance is studied using radiative transfer simulations. For the shorter wavelengths (λ&lt;500 nm), there are significant differences between the two. For instance, at 463 nm the difference can go up to 6 % at 30∘ solar zenith angle. The study also shows that, although DLER and BRDF surface reflectances have different properties, they are comparable for the longer wavelengths (λ&gt;500 nm). Based on this outcome, the GOME-2 surface DLER is compared with MODIS surface BRDF data from MODIS band 1 (centred around 645 nm) using both case studies and global comparisons. The conclusion of this validation is that the GOME-2 DLER compares well to MODIS BRDF data and that it does so much better than the non-directional LER database. The DLER approach for describing surface reflectivity is therefore an important improvement over the standard isotropic (non-directional) LER approaches used in the past. The GOME-2 surface DLER database can be used for the retrieval of atmospheric properties from GOME-2 and from previous satellite instruments like GOME and SCIAMACHY. It will also be used to support retrievals from the future Sentinel-5 UVNS (ultraviolet, visible, near-infrared, and short-wave infrared) satellite instrument.

Computational Modeling of Ultrasound C-Scan Imaging Using Transmitted Signal Peak Density

Ultrasound measurement is a relatively inexpensive and commonly used imaging tool in the health sector. The through-transmission process of ultrasound measurement has been extensively evaluated for detecting abnormalities in tissue pathology. Compared to standard imaging parameters such as amplitude and time of flight, quantitative ultrasound parameters in the frequency domain can provide additional details regarding tissue microstructures. In this study, pressure magnitude or amplitude variation in the frequency spectrum of the received signal was evaluated as a potential imaging technique using the spectral peak density parameter. Computational C-scan imaging analysis was developed through a finite element model. The magnitude variation in the received signal showed different patterns while interacting with and without inclusions. Images were reconstructed based on peak density values that varied with the presence of solid structure. The computational results were verified with the experimental C-scan imaging results from the literature. It was found that magnitude variation can be an effective parameter for C-scan imaging of thin structures. The feasibility of the study was further extended to identify the structure’s relative position along with the sample depth during C-scan imaging. While moving the structure in the direction of the sample depth, the pressure magnitude variation strongly followed a second-degree polynomial trend.