Time-specific Effects Research Articles

Effect of Capital Adequacy on Operational Efficiency of Commercial Banks in Kenya

This study investigates the impact of capital adequacy on the operational efficiency of Kenyan banks, highlighting its importance for financial stability and risk management using a two-step analytical approach: first, Stochastic Frontier Analysis was used to determine operational efficiency scores for each bank; second, a panel Generalized Method of Moments (GMM) regression model assessed the relationship between these scores and capital adequacy. The study employed a panel GMM Method, accounting for individual and time-specific effects as well as endogeneity and correlation biases. The study concentrated on data from 2008 to 2022, from verified audited financial statements from the Central Bank of Kenya and the respective banks' websites. The study revealed a positive relationship between capital adequacy and operational efficiency. Specifically, increased capital adequacy was associated with a 10.32% improvement in operational efficiency. The study also found that market structure plays a significant role in this relationship. Based on these findings, policymakers should adopt comprehensive strategies focusing on stringent capital adequacy regulations to enhance bank performance and stability.

A longitudinal analysis of local innovation in Italy: How do proximity measures matter?

ABSTRACT This paper investigates the factors influencing local innovation from a longitudinal perspective while assessing geographical, economic and technological proximity. The research hypotheses concern spatial interactions, spillover effects and proximity measures that best fit innovation patterns and territorial interactions in Italy. The estimation strategy is the spatial Durbin panel model. The optimal specification to handle cross-sectional dependence in the data was derived from statistical tests evaluating (i) individual-specific effects, (ii) time-specific effects and (iii) both individual and time effects. The model was estimated using data from 107 Italian provinces over 2010–2019. The results show that both endogenous and exogenous interaction effects drive innovation processes and the underlying spillovers are global. Economic proximity explains local innovation patterns more effectively than geographical contiguity and technological proximity.

Pathological and ultrastructural changes of Bellamya bengalensis under chronic carboxylic acid exposure at environmentally relevant levels: Inferences from general unified threshold model for survival (GUTS) predictions and hepatopancreatic integrity assessment

This study aimed to understand the effects of freshwater acidification, driven by industrial runoff, agricultural activities, and atmospheric deposition, on the freshwater mollusk Bellamya bengalensis. By systematically investigating the impact of two common carboxylic acids, acetic acid (AA) and benzoic acid (BA), this research employed diverse toxicological, pathological, and ecological assessments. We explored survival predictions through the generic unified threshold model of survival (GUTS-SD), examined oxidative stress responses, and investigated hepatopancreatic alterations. In the experimental design, Bellamya bengalensis were subjected to environmentally relevant sublethal concentrations (10%, 20% LC50) of AA (39.77 and 79.54 mg/l) and BA (31.41 and 62.82 mg/l) over 28 days. Acute toxicity tests revealed increased LC50 values, indicating heightened toxicity with prolonged exposure, particularly due to the greater potency of benzoic acid compared to acetic acid. The GUTS-SD model provided accurate predictions of time-specific effects on populations, presenting long-term exposure (100 days) LC50 values for AA (263.7 mg/l) and BA (330.9 mg/l). Sequentially, the integrated biomarker response (IBR) analysis across study intervals highlighted the 28-day interval as the most sensitive, with GST emerging as the most responsive enzyme to oxidative stress induced by AA and BA. Histopathological and ultrastructural assessments of the hepatopancreas showed severe alterations, including necrosis, vacuolation and disrupted micro-villi, which were especially pronounced in higher BA exposure concentrations. These findings highlight the health and survival impacts of carboxylic acid toxicity on Bellamya bengalensis, emphasizing the need for proactive measures to mitigate acidification in aquatic ecosystems. The broader ecological implications underscore the importance of effective management and conservation strategies to address ongoing environmental challenges

A pilot study on the time-specific effects of light exposure from a light emitting diode (LED) on cardiovascular development in Danio rerio

A pilot study on the time-specific effects of light exposure from a light emitting diode (LED) on cardiovascular development in Danio rerio

Effects of logistics performance on Vietnam’s exports: a quantitative analysis using the PPML method

This study aims to analyze the effects of logistics performance on Vietnam’s exports at both the overall level and in specific aspects. We investigate the linkage between logistics performance and Vietnam’s exports based on a panel of bilateral trade from Vietnam to 158 trading partners from 2007 to 2018. Using the Poisson pseudo-maximum likelihood method, the positive and significant effects of Vietnam’s and importing countries’ logistics performance on exports are identified. Our estimates become highly consistent after controlling for both time-specific effects and time-invariant country-fixed effects and remain robust to changes in the model specification, contributing reliable empirical evidence to the literature. Considering the specific aspects of logistics performance, we find the significant roles of the ability to track and trace consignments, the quality of logistics services, the customs clearance efficiency, and the timeliness of shipments in trade. From Vietnam’s perspective, improvements in tracking and tracing ability and timeliness can enhance exports to other countries, with larger effects than those of trading partners. Based on these findings, this study provides evidence for policymakers to effectively enhance trade with other countries by developing the national logistics system alongside further logistics cooperation with trading partners and with a greater focus on tracking and tracing ability and timeliness.

EFFECT OF ESG PERFORMANCE ON CORPORATE GREEN TECHNOLOGY INNOVATION: THE MEDIATING ROLE OF FINANCIAL CONSTRAINTS AND DIGITAL TRANSFORMATION

There is little research on the intrinsic mechanisms between environmental, social, and governance (ESG) performance and green technology innovation among firms in developing countries. Utilizing a dataset comprising Chinese A-share listed companies in Shanghai and Shenzhen for 2015–2020, this study employs a two-way fixed-effects modeling approach, accounting for industry- and time-specific effects. The results demonstrate an affirmative relationship between firms’ ESG performance and green technology innovation, which is reinforced by state-owned enterprises and firms with dual CEO positions. This study offers a scholarly foundation for the broader transition toward a greener economy and society in China.

FDI and Growth: A Re-look at Evidence on Developing Economies

Using cross-country data, this article investigates the impact of foreign direct investment (FDI) on growth in developing economies during globalisation. The study adopts an approach different from existing studies by categorising countries from Asia, Africa, Latin America, and the Caribbean based on FDI growth and per capita gross domestic product (GDP) growth relationship in the two phases: 1991–2004 and 2005–2019. In a sample of 29 countries, the least-squares dummy variable (LSDV) estimation shows a significant negative between FDI and per capita GDP controlling for both country-specific and time-specific effects and various other factors including gross domestic capital formation, inflation, physical infrastructure, human capital, trade openness, financial development and governance. This study confirms the positive impact of FDI in the earlier phase, while a significant negative impact on the later phase. The observed negative relationship holds for sub-sets of the sample countries for the entire period. These results are despite the importance of human capital, infrastructure, financial development, trade openness and governance along with FDI. These developing countries thus need to formulate complementary domestic economic policies, including institutional changes, which complement foreign direct investment in promoting per capita growth. JEL: F21, F43, O11, C23

A global multicohort study to map subcortical brain development and cognition in infancy and early childhood

The human brain grows quickly during infancy and early childhood, but factors influencing brain maturation in this period remain poorly understood. To address this gap, we harmonized data from eight diverse cohorts, creating one of the largest pediatric neuroimaging datasets to date focused on birth to 6 years of age. We mapped the developmental trajectory of intracranial and subcortical volumes in ∼2,000 children and studied how sociodemographic factors and adverse birth outcomes influence brain structure and cognition. The amygdala was the first subcortical volume to mature, whereas the thalamus exhibited protracted development. Males had larger brain volumes than females, and children born preterm or with low birthweight showed catch-up growth with age. Socioeconomic factors exerted region- and time-specific effects. Regarding cognition, males scored lower than females; preterm birth affected all developmental areas tested, and socioeconomic factors affected visual reception and receptive language. Brain–cognition correlations revealed region-specific associations.

Whole brain network effects of subcallosal cingulate deep brain stimulation for treatment-resistant depression

Ongoing experimental studies of subcallosal cingulate deep brain stimulation (SCC DBS) for treatment-resistant depression (TRD) show a differential timeline of behavioral effects with rapid changes after initial stimulation, and both early and delayed changes over the course of ongoing chronic stimulation. This study examined the longitudinal resting-state regional cerebral blood flow (rCBF) changes in intrinsic connectivity networks (ICNs) with SCC DBS for TRD over 6 months and repeated the same analysis by glucose metabolite changes in a new cohort. A total of twenty-two patients with TRD, 17 [15 O]-water and 5 [18 F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) patients, received SCC DBS and were followed weekly for 7 months. PET scans were collected at 4-time points: baseline, 1-month after surgery, and 1 and 6 months of chronic stimulation. A linear mixed model was conducted to examine the differential trajectory of rCBF changes over time. Post-hoc tests were also examined to assess postoperative, early, and late ICN changes and response-specific effects. SCC DBS had significant time-specific effects in the salience network (SN) and the default mode network (DMN). The rCBF in SN and DMN was decreased after surgery, but responder and non-responders diverged thereafter, with a net increase in DMN activity in responders with chronic stimulation. Additionally, the rCBF in the DMN uniquely correlated with depression severity. The glucose metabolic changes in a second cohort show the same DMN changes. The trajectory of PET changes with SCC DBS is not linear, consistent with the chronology of therapeutic effects. These data provide novel evidence of both an acute reset and ongoing plastic effects in the DMN that may provide future biomarkers to track clinical improvement with ongoing treatment.

The Effect of Trade Agreements on Korea’s Bilateral Trade Volume: Mitigating the Impact of Economic Uncertainty in Trading Countries

Purpose - This research empirically analyzes the influence of economic policy uncertainty and free trade agreements (FTAs) on bilateral trade volumes between Korea and its trading partners. The study investigates whether fluctuations in the Economic Policy Uncertainty Index (EPUI) for both Korea and its trading partners significantly impact trade volumes and whether the implementation of FTAs mitigates these effects.
 Design/methodology - The study employs dynamic panel data analysis using the system generalized method of moments (system GMM) estimation method to achieve its research objectives. It utilizes country-month-level panel data, including the EPUI, trade volume between Korea and its trading partner countries, and other pertinent variables. The use of system GMM allows for the control of potential endogeneity issues and the incorporation of country-specific and time-specific effects.
 Findings - The analysis yields significant results regarding the impact of economic policy uncertainty on Korea's exports and imports, particularly before the implementation of FTAs. An increase in the EPUI of trading partners leads to a notable increase in Korea's exports to them. Conversely, an increase in Korea's EPUI negatively affects its imports from trading partners. However, post-FTA implemen- tation, the influence of each country's EPUI on trade volume is neutralized, with no significant difference observed.
 Originality/value - This research contributes to the existing literature by providing empirical evidence on the interaction effects between economic policy uncertainty and FTAs on bilateral trade volumes. The study's uniqueness lies in its examination of how FTAs mitigate the impact of economic uncertainty on trade relations between countries. The findings underscore the importance of trade agreements as mechanisms to address economic risks and promote international trade relations. In a world where global market uncertainties persist, these insights can aid policymakers in Korea and other countries in enhancing their trade cooperation strategies and navigating challenges posed by evolving economic landscapes.

Time-specific impact of mono-benzyl phthalate (MBzP) and perfluorooctanoic acid (PFOA) on breast density of a Chilean adolescent Cohort

IntroductionHigh mammographic density is among the strongest and most established predictors for breast cancer risk. Puberty, the period during which breasts undergo exponential mammary growth, is considered one of the critical stages of breast development for environmental exposures. Benzylbutyl phthalate (BBP) and perfluorooctanoic acid (PFOA) are pervasive endocrine disrupting chemicals that may increase hormone-sensitive cancers. Evaluating the potential impact of BBP and PFOA exposure on pubertal breast density is important to our understanding of early-life environmental influences on breast cancer etiology. ObjectiveTo prospectively assess the effect of biomarker concentrations of monobenzyl phthalate (MBzP) and PFOA at specific pubertal window of susceptibility (WOS) on adolescent breast density. MethodThis study included 376 Chilean girls from the Growth and Obesity Cohort Study with data collection at four timepoints: Tanner breast stages 1 (B1) and 4 (B4), 1- year post- menarche (1YPM) and 2-years post-menarche (2YPM). Dual-energy X-ray absorptiometry was used to assess the absolute fibroglandular volume (FGV) and percent breast density (%FGV) at 2YPM. We used concentrations of PFOA in serum and MBzP in urine as an index of exposure to PFOA and BBP, respectively. Parametric G-formula was used to estimate the time-specific effects of MBzP and PFOA on breast density. The models included body fat percentage as a time-varying confounder and age, birthweight, age at menarche, and maternal education as fixed covariates. ResultsA doubling of serum PFOA concentration at B4 resulted in a non-significant increase in absolute FGV (β:11.25, 95% confidence interval (CI): −0.28, 23.49)), while a doubling of PFOA concentration at 1YPM resulted in a decrease in % FGV (β:-4.61, 95% CI: −7.45, −1.78). We observed no associations between urine MBzP and breast density measures. ConclusionIn this cohort of Latina girls, PFOA serum concentrations corresponded to a decrease in % FGV. No effect was observed between MBzP and breast density measures across pubertal WOS.

Linear panel regressions with two-way unobserved heterogeneity

We study linear panel regression models in which the unobserved error term is an unknown smooth function of two-way unobserved fixed effects. In standard additive or interactive fixed effect models the individual specific and time specific effects are assumed to enter with a known functional form (additive or multiplicative). In this paper, we allow for this functional form to be more general and unknown. We discuss two different estimation approaches that allow consistent estimation of the regression parameters in this setting as the number of individuals and the number of time periods grow to infinity. The first approach uses the interactive fixed effect estimator in Bai (2009), which is still applicable here, as long as the number of factors in the estimation grows asymptotically. The second approach first discretizes the two-way unobserved heterogeneity (similar to what Bonhomme et al., 2021 are doing for one-way heterogeneity) and then estimates a simple linear fixed effect model with additive two-way grouped fixed effects. For both estimation methods we obtain asymptotic convergence results, perform Monte Carlo simulations, and employ the estimators in an empirical application to UK house price data.

It does not matter how hard you work: The importance of task allocation for worker productivity

Using detailed high-frequency administrative data from a large retailer with an online presence in the UK we explore the determinants of worker productivity in a warehouse decant process. We distinguish between worker characteristics, time-specific effects, and task allocation as determinants of productivity and find a dominant role of the latter. This raises concerns about the assumption of random or identical task allocation made in studies when tasks are unobserved. This is especially relevant in the presence of output-related reward systems when workers will have an incentive to influence task allocation.

Analysis of factors influencing outcome following primary total knee arthroplasty

Introduction: Osteoarthritis is a chronic and painful disease which causes pain and loss of movement in the knee that lead to difficulty in performing daily activities. In this study, we analyze various factors like age, sex, BMI, waist/hip ratio, tourniquet time, KL grade of OA knee, use of preoperative tranexamic acid, affecting the outcome post total knee arthroplasty surgery in osteoarthritic patients. Outcome till 6 month was evaluated by mean knee range of motion, Knee society score, SF12 score.Results: In our study, 12 patients (40%) had osteoarthritis knees according to K-L grade III, and 18 patients (60%) had osteoarthritis knees according to K-L grade IV. There were 18 (60.0%) females and 12 (40.0%) males in our study, showing a slight preponderance of females. Leftsided affection was slightly more than right.In our study 16 patients (around 53%) were with BMI ranging from 29 to 32 with mean BMI of 31+_2.3 and Mean Waist Hip ratio was 80.7+-6.Average duration of surgery was around 125.2+-16.26 minutes.The postoperative Knee Society Score at the end of our follow up study at 6 Month is 79.30 Conclusion: We have provided an overview of factor-related progress to the scientific community, but also present time-specific effects to be able to better understand the importance of these factors for Total Knee replacements in the clinic. We conclude tourniquet time, total time of surgery, total blood loss had insignificant effect on functional outcome of patient over a follow up period of 6 months. Excellent results can be expected in patient of younger age and with low BMI & Waist: Hip Ratio, with no comorbidity. Preoperative functional outcome was significant following early KL grade 3 OA knee patients undergoing Total Knee Replacement compared to KL grade 4 knee initially, but over the period of 6 month follow up outcome was found comparable.

Moderate-intensity continuous training has time-specific effects on the lipid metabolism of adolescents.

Moderate-intensity continuous training (MICT) is used to observe lipidomic effects in adults. However, the efects of MICT on lipid metabolism in adolescents remain unclear. Therefore, we aimed to longitudinally characterize the lipid profile in adolescents during different periods of 6-week MICT. Fifteen adolescents undertook bicycle training at 65% of maximal oxygen consumption. Plasma samples were collected at four time points (T0, T1, T2, and T3). Targeted lipidomics was assessed by ultra-performance liquid chromatography-tandem mass spectrometry to characterize the plasma lipid profiles of the participants to identify the lipids present at differing concentrations and changes in lipid species with time. MICT afected the plasma lipid profiles of the adolescents. The concentrations of diglycerides, phosphatidylinositol, lysophosphatidic acid, lysophosphatidylcholine, and lysophosphatidylethanolamine were increased at T1, decreased at T2, and increased again at T3. Fatty acids (FAs) showed an opposite trend. Ether-linked alkylphosphatidylcholine and triglycerides were significantly increased and remained high. Sphingolipid concentrations initially decreased and then remained low. Therefore, a single bout of exercise had substantial efects on lipid metabolism, but by T3, fewer lipid species were present at significantly diferent concentrations and the magnitudes of the remaining diferences were smaller than those at earlier times. Among all the changed lipids, only DG(14:1/18:1), HexCer(d18:1/22:1) and FA(22:0) showed no significant correlations with any other 51 lipids (P < 0.05). Glycerides and phospholipids showed positive correlations with each other (P < 0.05), but FAs were significantly negatively correlated with glycerides and phospholipids while positively with other FAs (P < 0.05). Pathway enrichment analysis showed that 50% of the metabolic pathways represented were related to lipid metabolism and lipid biosynthesis. MICT increases ether-linked alkylphosphatidylcholine and triglyceride concentrations. Diglyceride, phosphatidylinositol, and lysophosphatidylcholine concentrations initially rise and then decrease 6 weeks after MICT, but FA concentrations show an opposite trend. These changes might correlate with lipid metabolism or biosynthesis pathways.

The timing of heat waves has multiyear effects on milkweed and its insect community.

Extreme heat events are becoming more frequent and intense as climate variability increases, and these events inherently vary in their timing. We predicted that the timing of a heat wave would determine its consequences for insect communities owing to temporal variation in the susceptibility of host plants to heat stress. We subjected common milkweed (Asclepias syriaca) plants to in-field experimental heat waves to investigate how the timing of heat waves, both seasonally and relative to a biotic stressor (experimental herbivory), affected their ecological consequences. We found that heat waves had multiyear, timing-specific effects on plant-insect communities. Early-season heat waves led to greater and more persistent effects on plants and herbivore communities than late-season heat waves. Heat waves following experimental herbivory had reduced consequences. Our results show that extreme climate events can have complex, lasting ecological effects beyond the year of the event-and that timing is key to understanding those effects.

Assessment of factors impacting outcome of primary total hip arthroplasty

Introduction: Hip replacement is one of the most successful surgeries in the clinic for the removal of painful joints. Hip osteoarthritis and femoral head necrosis are the 2 main reasons for hip replacement. Several factors are associated with the outcomes of surgery. Nonsurgical factors include gender, age, body mass index, prosthetic material, and risk factors. Surgical factors are anesthesia, postoperative complications, and rehabilitation. Considering the increasing demand for hip arthroplasty and the rise in the number of revision operations, it is imperative to understand factor-related progress and how modifications of these factors promotes recovery following hip replacement. In this review, we first summarize recent findings regarding crucial factors that influence the outcomes of artificial hip replacement surgery. These findings not only show the time-specific effect for the treatment and recovery from hip arthroplasty in the clinic, but also provide suitable choices for different individuals for clinicians to consider. This, in turn, will help to develop the best possible postoperative program for specific patients.Material & Methods: Our’s is a Cross-sectional study which included 32 individuals both male and female above the age of 20 years. All the patients who had undergone Primary Total Hip Replacement for isolated hip pathologies at our hospital; and all are evaluated for functional outcome using Harris Hip Score Pre-operatively, at 1 month, at 3 months, at 6 months and compared.Results: In our study there was a statistically significant association between BMI, Waist: Ratio, Comorbidity, Duration of surgery & Age and the outcome, which shows that the outcome is dependent on the BMI, Waist: Ratio, Comorbidity, Duration of surgery & Age of the patients.Conclusion: With the increasing numbers of patients receiving hip replacements every year, it is important to have a knowledge of the possible factors that may influence the outcomes of surgery in individual patients. However, how the novel findings of the factors are associated with the outcomes of surgery and how the variations should be assessed in different individuals are 2 main reasons for us to summarize the literature, and it is imperative to be aware of these factors for designing personalized therapy for individuals in the clinic.

Income windfalls and overweight: evidence from lottery wins

We examine the impact of an income windfall (from a lottery win) on an individual's overweight and Body Mass Index (BMI). We use longitudinal data from the United Kingdom, where a large proportion of the population plays the lottery, and retrieve income effect estimates using time and individual specific fixed effects alongside a set of relevant controls. Although our findings suggest any income windfall may lead to a contemporaneous increase in overweight, we document evidence that a £1,000 win reduces the probability of overweight in the range by up to 3 percentual points 12 months after the lottery win. Estimates are heterogeneous across working hours and educational attainment. A £1000 lottery win reduces the risk of overweight among low educated individuals by 4.5–5 percentual points (pp)12 months after the lottery win.

Cities in a pandemic: Evidence from China.

This paper studies the impact of urban density, city government efficiency, and medical resources on COVID-19 infection and death outcomes in China. We adopt a simultaneous spatial dynamic panel data model to account for (i) the simultaneity of infection and death outcomes, (ii) the spatial pattern of the transmission, (iii) the intertemporal dynamics of the disease, and (iv) the unobserved city-specific and time-specific effects. We find that, while population density increases the level of infections, government efficiency significantly mitigates the negative impact of urban density. We also find that the availability of medical resources improves public health outcomes conditional on lagged infections. Moreover, there exists significant heterogeneity at different phases of the epidemiological cycle.

Bayesian Markov-Switching Tensor Regression for Time-Varying Networks

Modeling time series of multilayer network data is challenging due to the peculiar characteristics of real-world networks, such as sparsity and abrupt structural changes. Moreover, the impact of external factors on the network edges is highly heterogeneous due to edge- and time-specific effects. Capturing all these features results in a very high-dimensional inference problem. A novel tensor-on-tensor regression model is proposed, which integrates zero-inflated logistic regression to deal with the sparsity, and Markov-switching coefficients to account for structural changes. A tensor representation and decomposition of the regression coefficients are used to tackle the high-dimensionality and account for the heterogeneous impact of the covariate tensor across the response variables. The inference is performed following a Bayesian approach, and an efficient Gibbs sampler is developed for posterior approximation. Our methodology applied to financial and email networks detects different connectivity regimes and uncovers the role of covariates in the edge-formation process, which are relevant in risk and resource management. Code is available on GitHub. Supplementary materials for this article are available online.