Curvilinear Regression Models Research Articles

Rhythm and shift frequency of strategic renewal in Indonesian firm performance

PurposeThis study aims to explore how manufacturing firms in emerging economies can effectively adjust the rhythm and shift frequency between exploitation and exploration renewal. The authors also examine how these strategic adjustments can significantly boost firm performance, offering insights into the dynamic process of strategic renewal.Design/methodology/approachThis study analyzes annual reports of 127 Indonesian manufacturing firms from 2014 to 2019, applying both linear and curvilinear regression models to examine the hypotheses. Data on exploration and exploitation renewal were meticulously gathered using computer-aided text analysis, using targeted keywords to identify strategic renewal efforts.FindingsThe study shows that a rather irregular balance rhythm between exploitation and exploration renewal surprisingly enhances firm performance. A curvilinear relationship emerges as performance peaks when the shift frequency of renewal occurs about three times. This relationship optimizes the strategic renewal processes, emphasizing that firms need to remain agile and adaptable in today’s dynamic market environment.Originality/valueThis study leverages organizational learning to assess how the paradoxical dimensions of exploration and exploitation renewal impact firm performance. By focusing on the temporal transition of these tensions, it provides insights into optimizing the rhythm and shift frequency of renewal, transitioning from a static to a dynamic accord.

Computational analysis of diameter eccentricity based and hyper diameter eccentricity based indices for linear saturated monocarboxylic acids

Chemical graph theory deals with chemical graphs, which are used to represent chemical systems. Topological indices of molecular graphs are an important area of research in chemical graph theory. These indices are numerical values associated with compounds that aim to establish connections between chemical structures and physical attributes, chemical reactivity, and biological activity. Many graph polynomials have been proposed to compute various topological indices. Quantitative structure-property relationship (QSPR) analysis of chemical compounds involves several regression methods that rely on these topological indices. In this article, we utilize the newly introduced DƐ-polynomial to calculate the eccentricitybased indices such as the diameter eccentricity based and hyper diameter eccentricity based index values for nineteen linear saturated monocarboxylic acids. Quantitative structureproperty relationship (QSPR) analysis is also performed for the seven thermodynamic properties of monocarboxylic acids. The relationship between thermodynamic properties and topological indices is explored using linear, quadratic and cubic regression models. The best fit curvilinear regression models were determined based on the R2 and RMSE values of the models. To further investigate the statistical significance of our models, we also conducted chi-square goodness-of-fit tests to identify the best fit models.

A QSPR analysis and curvilinear regression models for various degree-based topological indices: Quinolone antibiotics

Topological indices play an essential role in defining a chemical compound numerically and are widely used in QSPR/QSAR analysis. Using this analysis, physicochemical properties of the compounds and the topological indices are studied. Quinolones are synthetic antibiotics employed for treating the diseases caused by bacteria. Across the years, Quinolones have shifted its position from minor drug to a very significant drug to treat the infections caused by bacteria and in the urinary tract. A study is carried out on various Quinolone antibiotic drugs by computing topological indices through QSPR analysis. Curvilinear regression models such as linear, quadratic and cubic regression models are determined for all topological indices. These regression models are depicted graphically by extending for fourth degree and fifth degree models for significant topological indices with its corresponding physical property showing the variation between each model. Various studies have been carried out using linear regression models while this work is extended for curvilinear regression models using a novel concept of finding minimal RMSE. RMSE is a significant measure to find potential predictive index that fits QSAR/QSPR analysis. The goal of RMSE lies in predicting a certain property of a chemical compound based on the molecular structure.

Chemical applicability and curvilinear regression models of vertex‐degree‐based topological index: Elliptic Sombor index

AbstractChemical graph theory facilitates different tools that have significant applications in drug design and development. Recently Gutman et al., introduced a novel vertex‐degree‐based topological index called elliptic Sombor index and its application through geometric approach. This article focuses on chemical applicability of elliptic Sombor index through regression models using 22 benzenoid hydrocarbons. In this process, the chemical applicability of elliptic Sombor index with various physicochemical properties of benzenoid hydrocarbons through curvilinear regression models is carried out. The data of the statistical analysis shows that elliptic Sombor index is potential predictive index for the property polarizability.

Graph theoretic approach for calculation of new Banhatti indices VIA recent algebraic polynomials with a chemical application

In this article, we design new distance-based topological indices which are computed by a recent polynomial approach. Also, we present a chemical application on the suitability of these indices with some drugs used for the treatment of COVID-19 via QSPR analysis. Curvilinear regression models are obtained and analysed for the physico-chemical properties of the COVID-19 drugs. Our models and findings could aid in the development of new drugs for the treatment of COVID-19.

Maternal co-exposure to mercury and perfluoroalkyl acid isomers and their associations with child neurodevelopment in a Canadian birth cohort

BackgroundPerfluoroalkyl acids (PFAAs) within the broader class of per- and polyfluoroalkyl substances (PFAS) are present in human serum as isomer mixtures, but epidemiological studies have yet to address isomer-specific associations with child development and behavior. ObjectivesTo examine associations between prenatal exposure to 25 PFAAs, including perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) isomers, and child neurodevelopment among 490 mother–child pairs in a prospective Canadian birth cohort, the Alberta Pregnancy Outcomes and Nutrition (APrON) study. To consider the influence of a classic neurotoxicant, total mercury (THg), based on its likelihood of co-exposure with PFAAs from common dietary sources. MethodsMaternal blood samples were collected in the second trimester and child neurodevelopment was assessed at 2 years of age using the Bayley Scales of Infant and Toddler Development, 3rd Edition (Bayley-III). Linear or curvilinear multiple regression models were used to examine associations between exposures and neurodevelopment outcomes. ResultsSelect PFAAs were associated with lower Cognitive composite scores, including perfluoroheptanoate (PFHpA) (β = −0.88, 95% confidence interval (CI): −1.7, −0.06) and perfluorododecanoate (PFDoA) (β = −2.0, 95% CI: −3.9, −0.01). Non-linear relationships revealed associations of total PFOS (β = −4.4, 95% CI: −8.3, −0.43), and linear-PFOS (β = −4.0, 95% CI: −7.5, −0.57) and 1m-PFOS (β = −1.8, 95% CI: −3.3, −0.24) isomers with lower Language composite scores. Although there was no effect modification, including THg interaction terms in PFAA models revealed negative associations between perfluorononanoate (PFNA) and Motor (β = −3.3, 95% CI: −6.2, −0.33) and Social-Emotional (β = −3.0, 95% CI: −5.6, −0.40) composite scores. DiscussionThese findings reinforce previous reports of adverse effects of maternal PFAA exposure during pregnancy on child neurodevelopment. The unique hazards posed from isomers of PFOS justify isomer-specific analysis in future studies. To control for possible confounding, mercury co-exposure may be considered in studies of PFAAs.

Exploring the Symmetry of Curvilinear Regression Models for Enhancing the Analysis of Fibrates Drug Activity through Molecular Descriptors

Quantitative structure-property relationship (QSPR) modeling is crucial in cheminformatics and computational drug discovery for predicting the activity of compounds. Topological indices are a popular molecular descriptor in QSPR modeling due to their ability to concisely capture the structural and electronic properties of molecules. Here, we investigate the use of curvilinear regression models to analyze fibrates drug activity through topological indices, which modulate lipid metabolism and improve the lipid profile. Our QSPR approach predicts the physicochemical properties of fibrates based on degrees and distances from topological indices. Our results demonstrate that topological indices can enhance the accuracy of predicting physicochemical properties and biological activities of molecules, including drugs. We also conducted density functional theory (DFT) calculations on the investigated derivatives to gain insights into their optimized geometries and electronic properties, including symmetry. The use of topological indices in QSPR modeling, which considers the symmetry of molecules, shows significant potential in improving our understanding of the structural and electronic properties of compounds.

Lamina Abrasion Caused by High-Speed Drill in Unilateral Door Cervical Laminoplasty: A Clinical Investigation.

BACKGROUND The association of laminar opening extent (LOE) with sagittal canal diameter (SCD) and the cross-sectional area (CSA) in unilateral door cervical laminoplasty (UDCL) was previously analyzed. However, the lamina abrasion has been neglected, which could lead to unreliable results. The present study aims to develop the concept of effective laminar opening extent (ELOE) with consideration of the lamina abrasion and to analyze the relationships between ELOE and SCD as well as the CSA of the spinal canal. MATERIAL AND METHODS A total of 138 patients treated by UDCL were included. Pre- and postoperative SCDs and CSAs and cervical Japanese Orthopaedic Association (JOA) scores were compared to verify the effectiveness of the surgery. Linear and curvilinear regression models were used to assess the association between postoperative SCD/CSA increases and ELOE. RESULTS All surgeries were successfully performed. A total of 602 mini-plates were used, and 12-mm mini-plates was the most often used (n=402, 66.78%), while 16-mm were used the least (n=25, 4.15%). The SCDs, CSAs, and JOA scores were increased significantly after surgery (P0.939, P0.938, P.

QSPR Study and Distance-Based New Topological Descriptors of Some Drugs Used in the COVID-19 Treatment

In chemistry and medical sciences, it is essential to study the chemical, biological, clinical, and therapeutic aspects of pharmaceuticals. To save time and money, mathematical chemistry focuses on topological indices used in quantitative structure-property relationship (QSPR) models to predict the properties of chemical structures. The COVID-19 pandemic is widely recognized as the greatest life-threatening crisis facing modern medicine. Scientists have tested various antiviral drugs available to treat COVID-19 disease, and some have found that they help get rid of this viral infection. Antiviral drugs such as Arbidol, chloroquine, hydroxychloroquine, lopinavir, remdesivir, ritonavir, thalidomide, and theaflavin are used to treat COVID-19. In this paper, reformulated leap Zagreb indices are introduced. Then, the reformulated leap Zagreb indices, leap eccentric connectivity indices, and reformulated Zagreb connectivity indices of these antiviral drugs are calculated. Curvilinear and multilinear regression models predicting the physicochemical properties of these antiviral drugs in terms of proposed indices are obtained and analyzed. The findings and models of this study will shed light on new drug discoveries for the treatment of COVID-19.

Fundamental Aspects of Skin Cancer Drugs via Degree-Based Chemical Bonding Topological Descriptors.

Due to significant advancements being made in the field of drug design, the use of topological descriptors remains the primary approach. When combined with QSPR models, descriptors illustrate a molecule's chemical properties numerically. Numbers relating to chemical composition topological indices are structures that link chemical composition to physical characteristics. This research concentrates on the analysis of curvilinear regression models and degree-based topological descriptors for thirteen skin cancer drugs. The physicochemical characteristics of the skin cancer drugs are examined while regression models are built for computed index values. An analysis is performed for several significant results based on the acquired data.

QSPR Modeling with Topological Indices of Some Potential Drugs against Cancer

In Sri Lanka as well as the rest of the globe, cancer is the top cause of mortality. One of the key medicines in treating tumors is anticancer medications and delivery dendrimers. To prevent the formation of the rapid proliferation of cancer cells, several tests were carried out. Because of this, research on dendrimers and anti-cancer medications is crucial. Topological indices (TIs) are molecular descriptors numerical values corresponding to the physical characteristics of a molecule’s chemical structure. It costs money to determine a molecule’s physical characteristics in a lab since it takes a lot of materials, medications, and time. Therefore, the relevant information about molecules may be obtained by computing TIs. This study’s goals are to compute hitherto uncalculated eccentricity-based TIs for various anticancer structures and to use curvilinear regression models to forecast the physical characteristics of particular anticancer medications. These anticancer medications were given different TIs developed in this work, allowing the researchers to understand the physical, physicochemical, and chemical characteristics related to them. In addition comparative study of the novel indices with some well-known and mostly used indices in structure–property modeling and anticancer drugs in performed.

On Topological Descriptors and Curvilinear Regression Analysis of Antiviral Drugs Used in COVID-19 Treatment

Topological indices are used to research the chemical, biological, clinical, and medicinal properties of drugs in the field of chemical and medical sciences. The COVID-19 pandemic is widely regarded as the most life-threatening problem that modern medicine has ever faced. Scientists have tested usable antiviral agents and found that they have a significant impact on recovery from viral diseases such as COVID-19. Arbidol, Chloroquine, Hydroxychloroquine, Lopinavir, Remdesivir, Ritonavir, Thalidomide, and Theaflavin are some of the antiviral agents used in the treatment of COVID-19. In this paper we propose reduced reverse degree-based topological descriptors such as reduced reverse Zagreb indices, reduced reverse forgotten index, reduced reverse atom bond connectivity index, reverse geometric arithmetic index and reduced reverse general Randić index for the antiviral drugs of COVID-19. We also analyze the Quantitative Structure-Property Relationship (QSPR) of the proposed topological indices. Curvilinear regression models are obtained and analyzed for the physico-chemical properties of the COVID-19 drugs, in terms of the proposed indices. Our models and findings could aid in the development of new drugs for the treatment of COVID-19.

Effect of light backscattering from anterior segment structures on automated flare meter measurements.

To evaluate effect of maximal anterior cortical lens density, iris scatter and anterior chamber depth on laser flare photometry. Patients diagnosed with clinical uveitis were enrolled in the study. Clinical flare gradings were recorded upon the Standardization of Uveitis Nomenclature. Aqueous flare was measured with an automated device (Kowa FM-700). Back-scattering from anterior cortical lens and anterior iris surface was calculated from Scheimpflug images. A curvilinear regression model was used to calculate estimated values for each clinical grade. These values were used to split cases in Group I (laser flare photometry lower than estimated) and Group II (laser flare photometry higher than estimated). Mean anterior chamber depth, pupil aperture, maximal anterior cortical lens density and iris scatter values were compared between two groups. A stepwise multiple regression analysis was performed to determine the effect of clinical flare gradings and ocular parameters on aqueous flare measurements. The study included 228 eyes of 114 cases. Scheimpflug images were obtained from 105 eyes. Estimated aqueous flare measurements (in photons/milliseconds) were 4.87, 8.50, 14.81, 25.83, 45.04 and 136.93 for 0, 0.5+, 1+, 1.5+, 2+ and 3+ clinical flare respectively. Group II had higher maximal anterior cortical lens density than Group I (96.6 ± 37.1 vs 77.9 ± 17.1 pixel unit, p = 0.001). The measured aqueous flare was significantly related to clinical flare, maximal anterior cortical lens density and pupil aperture (adjusted R2: 0.480, p < 0.001). The back-scattered light from anterior cortical lens could affect laser flare photometry measurements. This effect might be quantified by Scheimpflug imaging.

Research on the interactive relationship and the optimal adaptation degree between land use benefit and industrial structure evolution: A practical analysis of Jiangsu province

Realizing the coordination of land use benefit (LUB) and industrial structure evolution (ISE) is a focus of discussion around high-quality urban development. Exploring the interactive relationship between LUB and ISE through theory and empiric, and proposing the optimal adaptation degree of ISE to maximize LUB is the main goal of our analysis. Entropy method, linear weighting method, curvilinear regression model, responsivity model and multi-objective function were adopted in this research. The results showed that: (1) From 2002 to 2017, the LUB level and ISE level in Southern Jiangsu and Northern Jiangsu differed greatly, on the contrary, this feature was not obvious in Central Jiangsu. (2) The ISE had an obvious unidirectional effect on LUB; and the response index of LUB to the ISE in Southern Jiangsu, Central Jiangsu and Northern Jiangsu showed an obvious three-level difference of “high-medium-low”. (3) The optimal adaptation degree of ISE in Southern Jiangsu, Central Jiangsu and Northern Jiangsu was 0.3880, 0.3213 and 0.4336, respectively, when the LUB was maximized. Based on the study results, some suggestions were given to provide a policy decision basis for different regions in Jiangsu province to reasonably improve LUB and narrow the regional development gap.

Analyzing the social factors affecting aviation development in countries by creating a mixed curvilinear regression model

Analyzing the social factors affecting aviation development in countries by creating a mixed curvilinear regression model

Abstract P548: Poorer Objective Sleep is Associated With Greater Arterial Stiffness and Worsening Cardiac Diastolic Function

Aim: Few studies have examined the association between objective sleep metrics and arterial and echocardiographic (left ventricular systolic/diastolic function) markers of sub-clinical cardiovascular disease (CVD). The present study examined the association of wrist actigraphy-assessed sleep metrics with arterial stiffness, endothelial dysfunction, and left ventricular systolic/diastolic function. Methods: Fifteen young, healthy adults (21-39y; 60% women) with no history of CVD, and no current sleep-disordered breathing (WatchPat200, Itamar Medical) or sleep complaints wore Actiwatch Spectrum Plus actigraphs for eight nights (Philips Respironics, Bend OR) with accompanying sleep logs. Participants underwent fasting vascular testing including central augmented aortic pressure (AP), carotid-femoral pulse wave velocity (cfPWV) to assess arterial stiffness (SphymocorXCEL TM ), brachial artery flow mediated dilation (FMD) to assess endothelial function, and 2D echocardiography to assess left ventricular function (Terason uSmart 3300 TM ). Left ventricular function was assessed by ejection fraction (EF%), left atrial volume index (LAVI), deceleration time (DT), and mitral valve E/e’ ratio (MVE/e’) using standardized methods. Bivariate correlations investigating the association between mean total sleep time (TST), sleep efficiency % (SE), sleep-onset latency (SOL), and wake after sleep time (WASO) with cardiovascular indices were conducted. Curvilinear regression models examining quadratic relationships between TST and the cardiovascular indices were conducted. Results: On average, participants obtained 6 hrs 44 min of TST (SD=29.1), with 86.0% SE (SD=3.1), 10.6 min SOL (SD=8.5), and 37.0 min WASO (SD=11.6). cfPWV (range: 4.8-7.5), EF% (range: 60.0-72.0), LAVI (range: 15.0-26.7 mL/m 2 ), and MVE/e’ (range: 3.2-7.8) were all within normal ranges according to age and sex normative standards. Mean FMD was 9.2% (SD=4.62, range: 4.3-19.8). Correlations indicated that greater SOL was associated with greater cfPWV (r=.63, p=0.01), and AP (r=.57, p=0.03). Lower SE (r= -.70, p=0.003) and higher WASO (r=.71, p=0.003) were associated with higher MVE/e’. WASO was associated with higher DT (r=.57, p=0.04). Curvilinear regression models revealed a quadratic relationship between TST and cfPWV (F[2,11]=9.78, p=0.004) such that shorter and longer TST were associated with greater cfPWV. No sleep metrics were associated with FMD, EF%, or LAVI. Conclusions: Among normal sleeping, apparently healthy young adults, with no history of CVD, lower levels of objective sleep quality and both shorter and longer sleep duration were associated with greater arterial stiffness, whereas only lower levels of objective sleep quality were related to worsening left ventricular diastolic dysfunction. These data may have implications for CVD risk reduction in young, healthy adults.

QSPR Analysis with Curvilinear Regression Modeling and Topological Indices

Topological indices are the real number of a molecular structure obtained via molecular graph G. Topological indices are used for QSPR, QSAR and structural design in chemistry, nanotechnology, and pharmacology. Moreover, physicochemical properties such as the boiling point, the enthalpy of vaporization, and stability can be estimated by QSAR/QSPR models. In this study, the QSPR (Quantitative Structure-Property Relationship) models were designed using the Gutman index, the product connectivity Banhatti index, the Variance of degree index, and the Sigma index to predict the thermodynamic properties of monocarboxylic acids. The relationship analyses between the thermodynamic properties and the topological indices were done by using the curvilinear regression method. It is used with the linear, quadratic and cubic equations of the curvilinear regression model. These regression models were then compared.

Sex and race differences in J-Tend, J-Tpeak, and Tpeak-Tend intervals

To facilitate the precision of clinical electrocardiographic studies of J-to-Tpeak (JTp) and Tpeak-to-Tend (Tpe) intervals, the study investigated their differences between healthy females and males, and between subjects of African and Caucasian origin. In 523 healthy subjects (254 females; 236 subjects of African origin), repeated Holter recordings were used to measure QT, JT, JTp, and Tpe intervals preceded by both stable and variable heart rates. Subject-specific curvilinear regression models were used to obtain individual QTc, JTc, JTpc and Tpec intervals. Rate hysteresis, i.e., the speed with which the intervals adapted after heart rate changes, was also investigated. In all sex-race groups, Tpe intervals were not systematically heart rate dependent. Similar to QTc intervals, women had JTc, and JTpc intervals longer than males (difference 20–30 ms, p < 0.001). However, women had Tpec intervals (and rate uncorrected Tpe intervals) shorter by approximately 10 ms compared to males (p < 0.001). Subjects of African origin had significantly shorter QTc intervals than Caucasians (p < 0.001). Gradually diminishing race-difference was found for JTc, JTpc and Tpec intervals. JTc and JTpc were moderately increasing with age but Tpe/Tpec were not. Rate hysteresis of JTp was approximately 10% longer compared to that of JT (p < 0.001). In future clinical studies, Tpe interval should not be systematically corrected for heart rate and similar to the QT interval, the differences in JT, JTp and Tpe intervals should be corrected for sex. The differences in QT and JT, and JTp intervals should also be corrected for race.

Relationship of pelvis and torso angular jerk to hand velocity in female softball hitting

ABSTRACTThe purpose of this study was to determine the influence of pelvis and torso angular jerk on a performance indicator of hitting, specifically hand velocity. Eighteen softball athletes were analysed (20.3 ± 1.6 years; 164.9 ± 24.9 cm; 74.4 ± 14.0 kg). Participants were instructed to execute 3 maximum effort swings off a stationary tee at the middle “strike-zone” location. Angular jerk data were analysed during the acceleration phase of the swing, the time between foot contact and ball contact. Quadratic regression analyses were conducted to examine the relationship of minimal pelvis angular jerk and minimal torso angular jerk to angular hand velocity at ball contact. No significant relationship was found between pelvis angular jerk and angular hand velocity at ball contact (r = 0.192, p = 0.754). The curvilinear regression model for pelvis angular jerk produced: R2 = 0.037; F (2, 17) = 0.288; p = 0.754. Lack of significant findings suggests a relationship between jerk and angular hand velocity does not exist within female softball hitting. Future research should investigate the timing of minimal jerk through the acceleration phase as a predictor of angular hand velocity, rather than the value of jerk itself.

Heart Rate Correction of the J-to-Tpeak Interval

Drug-induced changes of the J to T peak (JTp) and J to the median of area under the T wave (JT50) were reported to differentiate QT prolonging drugs that are predominant blockers of the delayed potassium rectifier current from those with multiple ion channel effects. Studies of drug-induced JTp/JT50 interval changes might therefore facilitate cardiac safety evaluation of new pharmaceuticals. It is not known whether formulas for QT heart rate correction are applicable to JTp and JT50 intervals. QT/RR, JTp/RR, and JT50/RR profiles were studied in 523 healthy subjects aged 33.5 ± 8.4 years (254 females). In individual subjects, 1,256 ± 220 electrocardiographic measurements of QT, JTp, and JT50 intervals were available including a 5-minute history of RR intervals preceding each measurement. Curvilinear, linear and log-linear regression models were used to characterize individual QT/RR, JTp/RR, and JT50/RR profiles both without and with correction for heart rate hysteresis. JTp/RR and JT50/RR hysteresis correction needs to be included but the generic universal correction for QT/RR hysteresis is also applicable to JTp/RR and JT50/RR profiles. Once this is incorporated, median regression coefficients of the investigated population suggest linear correction formulas JTpc = JTp + 0.150(1-RR) and JT50c = JT50 + 0.117(1-RR) where RR intervals of the underlying heart rate are hysteresis-corrected, and all measurements expressed in seconds. The established correction formulas can be proposed for future clinical pharmacology studies that show drug-induced heart rate changes of up to approximately 10 beats per minute.