scholarly journals How Rapidly Do The Road Fatality Rates of 37 Countries Converge Over Time?

2019 ◽  
Vol 13 (1) ◽  
pp. 169-181
Author(s):  
Yu Sang Chang ◽  
Sung Jun Jo
Keyword(s):  
Coefficient Of Variation ◽  
Reference Group ◽  
Road Crashes ◽  
The Road ◽  
Future Goals ◽  
Convergence Method ◽  
Road Fatality ◽  
Catch Up ◽  
Γ Convergence ◽  
Over Time

Background: Road crashes kill about 1.3 million people worldwide every year and severely injure an estimated 50 million. This paper examined two associated questions of convergence as to whether countries with initially high fatality rates tend to improve faster catch-up. Also, it was examined whether dispersion of road fatality rates among countries decreased over time. Methods: Using γ convergence and σ convergence, a total of 37 countries with reliable fatality data from 1994 to 2015 were analyzed. Common measures of dispersion include the standard deviation or coefficient of variation. For σ convergence, coefficient of variation was selected. Results: Results indicate that statistically valid patterns of convergence toward both catch-up effect and reduction of dispersion exist for the total group of countries. However, a wide variation in the pattern and speed of convergence was discovered for the subgroups of countries categorized by income level and regions. Conclusion: Convergence method helps to identify the most appropriate reference group for a given country in planning future goals for improving road fatality rate and catch-up speed. The findings from this research indicate that the speed of catch-up among different subgroups of countries varied.

scholarly journals FLOW OVER TIME PROBLEM WITH INFLOW-DEPENDENT TRANSIT TIMES

2018 ◽  
Vol 23 (1) ◽  
pp. 49-56
Author(s):  
Durga Prasad Khanal ◽  
Urmila Pyakurel ◽  
Tanka Nath Dhamala
Keyword(s):  
Network Flow ◽  
Time Horizon ◽  
The Road ◽  
Transit Times ◽  
Time Problem ◽  
Fast Flow ◽  
Static Flow ◽  
Time Expanded Network ◽  
Flow Over Time ◽  
Over Time

 Network flow over time is an important area for the researcher relating to the traffic assignment problem. Transmission times of the vehicles directly depend on the number of vehicles entering the road. Flow over time with fixed transit times can be solved by using classical (static) flow algorithms in a corresponding time expanded network which is not exactly applicable for flow over time with inflow dependent transit times. In this paper we discuss the time expanded graph for inflow-dependent transit times and non-existence of earliest arrival flow on it. Flow over time with inflow-dependent transit times are turned to inflow-preserving flow by pushing the flow from slower arc to the fast flow carrying arc. We gave an example to show that time horizon of quickest flow in bow graph GB was strictly smaller than time horizon of any inflow-preserving flow over time in GB satisfying the same demand. The relaxation in the modified bow graph turns the problem into the linear programming problem.

scholarly journals The Road to Parenthood: Income and First Births in Sweden

2016 ◽  
Vol 50 ◽  
pp. 31-52 ◽  
Author(s):  
Ernesto Germán Silva
Keyword(s):  
Gender Differences ◽  
Positive Association ◽  
Income Effect ◽  
Entire Population ◽  
Men And Women ◽  
The Road ◽  
The Moment ◽  
Over Time

This paper considers the effect of income on the risk of having the first births in Sweden from 1968 to 2009. Variations by gender are given particular atention. The study follows men and women from the moment they turn 18 until they enter parenthood and it is based on register-based data covering the entire population of Sweden. Complementary log-log models show that there is a positive association between income and the risk of childbearing. The association gets stronger over time and the differences between men and women diminish. Gender differences appear when the income effect is related to the demand for work in the economy. An income above the median does not increase the risk of childbearing for women when the demand for work is relatively high.

A Note on Rainfall Variability and Trends in Nigeria: Implications for Agricultural Production*

2021 ◽  
pp. 232102222110514
Author(s):  
Kolawole Ogundari ◽  
Adebola Abimbola Ademuwagun ◽  
Ogechukwu Appah
Keyword(s):  
Food Security ◽  
Coefficient Of Variation ◽  
Agricultural Production ◽  
Hypothesis Test ◽  
Rainfall Variability ◽  
Climatic Variability ◽  
Least Square ◽  
Annual Rainfall ◽  
Average Annual Rainfall ◽  
Over Time

The climatic change crisis has led to a renewed interest in understanding the dynamic of climatic variability over time. This is because rainfall variability in response to climate change poses a severe threat to global food security and agricultural production in general. As a result of this, the study investigates the convergence of rainfall variability in Nigeria. We use historical climate data on annual rainfall collected from meteorological stations across 12 states and covering 1992–2013. This gives rise to a balanced panel data of 12 states and 20 periods, which yields 240 observations. The study used a sigma convergence hypothesis test estimated using ordinary least square, fixed-effect and feasible generalized least square models. The coefficient of variation is taken as a measure of rainfall variability in the study. The results showed a negative (declining) linear correlation between rainfall’s coefficient of variation and data year. This means that rainfall variability decreased over time. This indicates evidence of convergence of rainfall, which means states with lower average annual rainfall are catching up on states with higher average annual rainfall over time. And, from the agricultural production standpoint, this result shows that the potential threat of rainfall variability to food security is not severe. In addition, it indicates a decrease in risk and uncertainty in food crop production associated with rainfall variability. JEL Classifications: O13, O55, Q10, Q54

Serum Uric Acid Levels and Their Changes and Risk of Stroke: A 7-Year Prospective Cohort Study in Northwest China

2021 ◽  
pp. 1-10
Author(s):  
Shan Zheng ◽  
Yan Luo ◽  
Qian Miao ◽  
Zhiyuan Cheng ◽  
Yanli Liu ◽  
...  
Keyword(s):  
Uric Acid ◽  
Cohort Study ◽  
Serum Uric Acid ◽  
Prospective Cohort Study ◽  
Prospective Cohort ◽  
Reference Group ◽  
Northwest China ◽  
Stroke Incidence ◽  
Increased Risk ◽  
Over Time

<b><i>Introduction:</i></b> It is not clear whether serum uric acid (SUA) levels and their changes over time are associated with the risk of stroke. A 7-year prospective cohort study in northwest China was conducted to analyze effects of SUA and their changes on the risk of stroke. <b><i>Methods:</i></b> A total of 23,262 individuals without cardiovascular disease in the Jinchang cohort were followed up for an average of 5.26 years. The Cox proportional hazard model was used to estimate the hazard ratios (HRs) and 95% confidence interval (95% CI) of stroke incidence to SUA and relative changes in SUA. Sensitivity analysis was performed after controlling the effect of renal insufficiency. <b><i>Results:</i></b> Baseline SUA and relative changes in SUA were positively correlated with the incidence of stroke in both males and females (<i>p</i> for overall association &#x3c;0.0001). Stroke risk increased by 4.6% per 10% increase in the relative change of SUA (HR = 1.046, 95% CI, 1.007–1.086). The fully adjusted regression analysis demonstrated that only the large gain (&#x3e;30%) in SUA was associated with an increased risk of stroke by 36.5% (95% CI, 1.8–83.0%), compared with the reference group (participants within ±10% changes in SUA). The same trend was observed in people with normal baseline SUA. In the unadjusted model, the risk of stroke associated with elevated SUA was significantly higher in the hyperuricemia group than in the normal SUA group. <b><i>Conclusion:</i></b> High initial SUA concentration and an increase in SUA concentration over time would increase the risk of stroke, and this means that there is no safe increase in SUA.

Social Cars

2014 ◽  
pp. 176-200
Author(s):  
Ronald Schroeter ◽  
Alessandro Soro ◽  
Andry Rakotonirainy
Keyword(s):  
Mobile Technologies ◽  
Transport Systems ◽  
Self Awareness ◽  
Intelligent Transport Systems ◽  
Intelligent Algorithms ◽  
Intelligent Transport ◽  
Locative Media ◽  
The Road ◽  
Over Time

Intelligent Transport Systems (ITS) encompass sensing technologies, wireless communication, and intelligent algorithms, and resemble the infrastructure for ubiquitous computing in the car. This chapter borrows from social media, locative media, mobile technologies, and urban informatics research to explore three classes of ITS applications in which human behavior plays a more pivotal role. Applications for enhancing self-awareness could positively influence driver behavior, both in real-time and over time. Additionally, tools capable of supporting our social awareness while driving could change our attitude towards others and make it easier and safer to share the road. Lastly, a better urban awareness in and outside the car improves our understanding of the road infrastructure as a whole. As a case study, the authors discuss emotion recognition (emotions such as aggressiveness and anger are a major contributing factor to car crashes) and a suitable basis and first step towards further exploring the three levels of awareness, self-, social-, and urban-awareness, in the context of driving on roads.

scholarly journals Methodological and physiological variability within the ventilatory response to hypoxia in humans

2000 ◽  
Vol 88 (5) ◽  
pp. 1924-1932 ◽  
Author(s):  
Shu Zhang ◽  
Peter A. Robbins
Keyword(s):  
Coefficient Of Variation ◽  
Ventilatory Response ◽  
Systematic Variation ◽  
Hypoxic Ventilatory Response ◽  
Mean Values ◽  
Careful Choice ◽  
Physiological Variability ◽  
Coefficients Of Variation ◽  
Ventilatory Response To Hypoxia ◽  
Over Time

Measurement of the acute hypoxic ventilatory response (AHVR) requires careful choice of the hypoxic stimulus. If the stimulus is too brief, the response may be incomplete; if the stimulus is too long, hypoxic ventilatory depression may ensue. The purpose of this study was to compare three different techniques for assessing AHVR, using different hypoxic stimuli, and also to examine the between-day variability in AHVR. Ten subjects were studied, each on six different occasions, which were ≥1 wk apart. On each occasion, AHVR was assessed using three different protocols: 1) protocol SW, which uses square waves of hypoxia; 2) protocol IS, which uses incremental steps of hypoxia; and 3) protocol RB, which simulates an isocapnic rebreathing test. Mean values for hypoxic sensitivity were 1.02 ± 0.48, 1.15 ± 0.55, and 0.93 ± 0.60 (SD) l ⋅ min− 1 ⋅ %− 1for protocols SW, IS, and RB, respectively. These differed significantly ( P < 0.01). The coefficients of variation for measurement of AHVR were 20, 23, and 36% for the three protocols, respectively. These were not significantly different. There was a significant physiological variation in AHVR ( F 50,100 = 3.9, P < 0.001), with a coefficient of variation of 26%. We conclude that there was relatively little systematic variation between the three protocols but that AHVR varies physiologically over time.

From catching up to industrial leadership: towards an integrated market-technology perspective. An application of semantic patent-to-patent similarity in the wind and EV sector

2020 ◽  
Author(s):  
Daniel S Hain ◽  
Roman Jurowetzki ◽  
Primoz Konda ◽  
Lars Oehler
Keyword(s):  
Language Processing ◽  
Electric Vehicles ◽  
Technological Changes ◽  
Catching Up ◽  
Industrial Leadership ◽  
Catch Up ◽  
Processing Techniques ◽  
Changes Over Time ◽  
Empirical Case Studies ◽  
Over Time

Abstract Studies on catching up and industrial leadership have often used market-related variables to evaluate the catch-up trajectories of latecomer countries and firms. In this study, we aim to enhance our understanding of these concepts by presenting an integrated market-technology framework. Using natural language processing techniques allows us to go beyond patent numbers and analyze patent novelty and impact as well as technological changes over time. In empirical case studies on wind energy and electric vehicles in China, Japan, and South Korea, we compare and identify country and sector-specific catch-up trajectories and potential catch-up traps.

Contrast magnetic resonance imaging for measurement of cartilage glycosaminoglycan content in dogs: A pilot study

2013 ◽  
Vol 26 (02) ◽  
pp. 100-104 ◽  
Author(s):  
M. C. Stewart ◽  
L. Ciobanu ◽  
P. D. Constable ◽  
J. F. Naughton
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Coefficient Of Variation ◽  
Signal Intensity ◽  
Linear Regression Analysis ◽  
Resonance Imaging ◽  
Post Contrast ◽  
Enhanced Mri ◽  
Over Time

SummaryObjective: To assess the ability of a contrast-enhanced magnetic resonance imaging (MRI) technique to quantitatively determine glycosaminoglycan content in canine articular cartilage.Methods: Fifty-four full-thickness cartilage discs were collected from the femorotibial and scapulohumeral joints of three adult dogs immediately following euthanasia. One set of discs from each dog was analysed for glycosaminoglycan content using a colourimetric laboratory assay. The remaining position-matched set of discs from contralateral limbs underwent pre- and post-contrast gadolinium-enhanced MRI, using repeated saturation recovery pulse sequences which were used to generate calculated T1 maps of the cartilage discs. Linear regression analysis was then performed relating delayed gadolinium-enhanced MRI T1 calculated signal intensity to the cartilage glycosaminoglycan content normalized to DNA content. Repeatability of triplicate measurements was estimated by calculating the coefficient of variation.Results: Mean coefficient of variation estimates for the gadolinium-enhanced MRI T1 signal intensity values for nine sampling sites from three dogs ranged from 5.9% to 7.5%. Gadolinium-enhanced MRI T1 signal intensity was significantly correlated (p <0.05) with normalized glycosaminoglycan content in two dogs (r = 0.79, p = 0.011; r = 0.78, p = 0.048), but not in the third dog (r = 0.53, p = 0.071).Clinical significance: Gadolinium-enhanced MRI assessment of cartilage may be predictive of glycosaminoglycan content and therefore offer an in vivo assessment of changes in cartilage characteristics over time. Additional studies appear indicated to determine the reliability and clinical applicability of gadolinium-enhanced MRI in detecting changes in cartilage over time.

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