Time-frequency co-movement between COVID-19, crude oil prices, and atmospheric CO2 emissions: Fresh global insights from partial and multiple coherence approach.

This paper endeavors to analyze and provide fresh global insights from the asymmetric nexus between the recent outbreak of COVID-19, crude oil prices, and atmospheric CO2 emissions. The analysis employs a unique Morlet's wavelet method. More precisely, this paper implements comprehensive wavelet coherence analysis tools, including continuous wavelet coherence, partial wavelet coherence, and multiple wavelet coherence to the daily dataset spanning from December 31, 2019 to May 31, 2020. From the frequency perspective, this paper finds significant wavelet coherence and vigorous lead and lag connections. This analysis ascertains significant movement in variables over frequency and time domain. These results demonstrate strong but varying connotations between studied variables. The results also indicate that COVID-19 impacts crude oil prices and the most contributor to the reduction in CO2 emissions during the pandemic period. This study offers practical and policy implications and endorsements for individuals, environmental experts, and investors.

Impact of technological innovation and renewable energy on ecological footprint in G20 countries: The moderating role of institutional quality.

The connection between ecological footprint and economic complexity has significant implications for environmental sustainability regarding the policy. Additionally, institutional quality is crucial in ensuring environmental sustainability and moderating the link between economic complexity and ecological footprint. The task of achieving sustainable environmental development and preventing further degradation of the environment poses a formidable challenge to policymakers. This study delves into the significance of technology innovation and renewable energy in creating a more sustainable environment. Recognizing the need for a more critical review, this research establishes the dynamic linkage between ecological footprint, renewable energy consumption, and technological innovation, especially in conjunction with a moderating component, particularly institutional quality, in G20 countries from 1990 to 2021. We employ advanced panel approaches to address panel data analysis concerns, such as cross-sectional dependence, slope heterogeneity, unit root, cointegration test and CS-ARDL. The long-term estimator indicates that renewable energy and technological innovation negatively but significantly impact the ecological footprint. Whilst economic growth, FDI, and urbanization have shown a positive and significant impact on ecological footprint; institutional quality negatively moderates the relationship between ecological footprint, renewable energy, and technological innovation in the G20 countries. Further evidence from the Dumitrescu-Hurlin Granger causality test shows that efforts to expand access to renewable energy, technological advancements, and economic growth will significantly affect environmental impacts. Based on our results, it is imperative to introduce more favorable legislation and encourage technological advancements in the field of renewable energy if we want to achieve our sustainable development objectives.

Effect of cementing technique on aseptic stem loosening in cemented primary total hip arthroplasty: a systematic review and meta-analysis.

Aseptic stem loosening after total hip arthroplasty surgery is the commonest complication, whether stem is cemented or uncemented. The aseptic cemented stem loosening has been a challenging problem over the years and a leading cause for revision since the inception of total hip arthroplasty. The objective of systematic review and meta-analysis was to determine the impact of cementing technique on aseptic stem loosening in total hip arthroplasty. Methods: Cochrane, CINAHL, Embase, Google scholar, Medline, PubMed were searched in 13 December 2020. Two independent investigators extracted the data and a third investigator's involvement was reached on consensus. A total of 37 studies of revision rate due to aseptic loosening were reviewed by using fixed/random effects size and were grouped by cementing technique and studies' characteristics. The data were analyzed through Meta-Essentials and RStudio. Results: In revision total hip arthroplasty, retained femoral components revisions rate due to aseptic loosening were recorded in 37 studies involving 6167 cases. Aseptic loosening rate collectively was 5.8% (CI 95%, 0.03-0.08) and mean follow-up of study was 12.5 years. The average follow-up period, mean age at index revision surgery and percentage of aseptic loosening were insignificantly associated with revision rate (P≥0.05), in meta-regression univariant analyses. Conclusion: This investigative analysis showed that there is a minimal difference between results of cementing techniques of total hip arthroplasty in femoral components in long-term follow-ups, and usually have a low risk of failure.

Effect of body mass index on duration of total knee replacement surgery: A prospective cross sectional study.

Introduction: Obesity and increased BMI has raised concerns throughout the globe. As obesity is often associated with many serious medical conditions. Obesity, older age and gender are major contributing factors for knee replacement surgeries. We aimed to compare the mean duration of surgery in obese and non-obese patients undergoing total knee replacement. Methods: A Cross-sectional study is conducted at the orthopedic department at Shifa international hospital, Islamabad during June 2021-Dec 2021. Study is conducted to assess the effect of BMI on duration of total knee arthroplasty. Sample size was calculated to be 105 with 95% confidence limit. Data will be analyzed using SPSS version 22. Quantitative variables like age, BMI and duration of surgery were presented as mean and standard deviation. Qualitative variables like gender, laterality (unilateral/bilateral), and ASA were presented as frequency and percentage. Results: There were more females undergoing the procedure than males. The predominant age group was found to be 56-65 years. On BMI classification scale, a far greater number of individuals were found to be obese constituting more than ⅗ of the study population and almost ⅕ of the patients were overweight. The Association of BMI Classification & Duration of Surgery has a significant p value of 0.00. Conclusion: A linear and direct relation was observed between body mass index and duration of surgery. There may be other contributing factors and will need more data and research.

Testing the heterogeneous effect of air transport intensity on CO2 emissions in G20 countries: An advanced empirical analysis.

This study investigates the heterogeneous impact of air transport intensity, air passenger transport, and air freight transport on air transport carbon emissions in G20 countries for the period of 1990-2016. The paper employs a robust and advanced fixed-effect panel quantile regression model that considers unobserved discrete and distributional heterogeneity. Our empirical results show that the impact of the independent variables on air transport carbon emissions is quite heterogeneous across various quantiles. More specifically, the effect of air transport intensity, air passenger transport, and air freight transport on carbon emissions is positive and becomes more assertive with the increasing trend at upper quantiles and is quite heterogeneous across all quantiles. Economic growth, urbanization, and tourism are significant contributing factors in enhancing air transport CO2 emissions, while crude oil price significantly reduces CO2 emissions. The Dumitrescu and Hurlin causality test estimates indicate that a bidirectional relationship extends from air transport intensity, air passenger transport, and air freight transport to air transport CO2 emissions. The findings underline the need for cleaner, renewable, and environmentally sustainable energy sources for air transport operations.

The nexus between road transport intensity and road-related CO2 emissions in G20 countries: an advanced panel estimation.

This study determines the dynamic linkages between road transport intensity, road transport passenger and road transport freight, and road carbon emissions in G20 countries in the presence of economic growth, urbanization, crude oil price, and trade openness for the period of 1990 to 2016, under the multivariate framework. This study employs the residual-based Kao and Westerlund cointegration technique to find long-run cointegration, and continuously updated bias-corrected (CUP-BC) and continuously updated fully modified (CUP-FM) methods to check the long-run elasticities between the variables. The long-run estimators' findings suggest a positive and significant impact of road transport intensity, road passenger transport, road freight transport on road transport CO2 emissions. Economic growth and urbanization are significant contributing factors in road transport CO2 emissions, while trade openness and crude oil price significantly reduce road transport CO2 emissions. The Dumitrescu and Hurlin causality test results disclose unidirectional causality from road transport intensity and road transport freight to the road transport CO2 emissions. However, the causality between road passenger transport and road transport CO2 emissions is bidirectional. Finally, comprehensive policy options like subsidizing environmental-friendly technologies, developing green transport infrastructure, and enacting decarbonizing regulations are suggested to address the G20 countries' environmental challenges.

Non-linear spatial linkage between COVID-19 pandemic and mobility in ten countries: A lesson for future wave.

BACKGROUND: Restrictive measures enacted in response to the COVID-19 pandemic have resulted in dramatic and substantial variations in people's travel habits and behaviors worldwide. This paper empirically examines the asymmetric inter-linkages between transportation mobility and COVID-19. METHODS: Using daily data from 1st March 2020 to 15th July 2020, this study draws the dynamic and causal relationships between transportation mobility and COVID-19 in ten selected countries (i.e., USA, Brazil, Mexico, UK, Spain, Italy, France, Germany, Canada, and Belgium). To systematically analyze how the quantiles of COVID-19 (transportation mobility) affect the quantiles of transportation mobility (COVID-19), a complete set of non-linear modeling including the quantile-on-quantile (QQ) regression and quantile Granger causality in mean is applied. RESULTS: Our preliminary findings strictly reject the preposition of data normality and highlight that the observed relationship is highly correlated and quantile-dependent. The empirical results demonstrate the heterogeneous dependence between COVID-19 and transportation mobility across quantiles. The findings acclaim the presence of a significant positive association between COVID-19 and transportation mobility in the USA, UK, Spain, Italy, Canada, France, Germany and Belgium, predominantly at upper quantiles, but results are contrasting in the case of Brazil and Mexico. In addition, either lower or upper quantiles of both variables indicate a declining negative effect of transportation mobility on COVID-19. Furthermore, the outcomes of quantile Granger causality in mean conclude a bidirectional causal link between COVID-19 and transportation mobility for almost all sample countries. Unlike them, France has found unidirectional causality that extends from COVID-19 to transportation mobility. CONCLUSIONS: We may conclude that COVID-19 leads to a reduction in transportation mobility. On the other hand, the empirical results quantify that excessive transportation mobility levels stimulate pandemic cases, and social distancing is one of the primary measures to encounter infection transmission. Imperative country-specific policy implications pertaining to public health, potential virus spread, transportation, and the environment may be drawn from these findings.

Alvarado scoring system in prediction of acute appendicitis.

OBJECTIVE: To evaluate the diagnostic accuracy of Alvarado score for the prediction of acute appendicitis. STUDY DESIGN: Analytical study. PLACE AND DURATION OF STUDY: This study was carried out in the Department of Surgery, Pakistan Institute of Medical Sciences (PIMS), Islamabad, during the period from January 15, 2009 to July 15, 2010. METHODOLOGY: The study included all adult patients of either gender who presented with clinical findings suggestive of acute appendicitis, who were assigned Alvarado score of < 4 pre-operatively and subsequently underwent emergency appendicectomy with histological examination of the resected specimens. Based on the Alvarado score, the patients were stratified into two groups. i.e. Group I (with a score of > 7) and Group II (with a score of 5-7). Alvarado score was compared with the histopathology. The data was subjected to statistical analysis to measure the objective. RESULTS: The overall sensitivity, specificity, positive predictive value and negative predictive value of Alvarado score for acute appendicitis were 66%, 81%, 96%, 29% respectively. The sensitivity was higher though not significant, for males with a score over 7 than females with similar scores (97% vs. 92%). However, for scores less than 7, sensitivity among males was significantly higher than females with similar scores (79% vs. 61%; p < 0.05). CONCLUSION: The presence of a high Alvarado score in adult males is highly predictive of acute appendicitis, however, in women of child bearing age other causes of similar clinical presentation lead to a low diagnostic accuracy of the score.