Mean Return Research Articles

QOL-25. DIGITAL PHENOTYPING OF PERIOPERATIVE MOBILITY METRICS IN PATIENTS UNDERGOING SURGICAL RESECTION OF SKULL BASE TUMORS

Abstract Current methods to assess quality of life and recovery after surgery for skull base tumors are limited and often biased by subjective patient-reported assessments, while objective, in-situ assessments are lacking. Smartphone-based digital phenotyping has been increasingly studied across pathologies, utilizing built-in technologies to measure behavioral patterns pertaining to sleep, physical mobility, social interactions, and cognitive functioning, among others. Here, we report our initial experience with smartphone-based digital phenotyping in patients who underwent resection of skull base lesions. Patients seen at our multi-disciplinary skull base center were enrolled under an institutional board-approved protocol and installed the Beiwe application, which passively collected GPS data 20 days pre- and up to 140 days post-surgery. Variables measured included time spent at home, number of separate significant places visited outside home, daily walking time, and daily number of steps taken. 26 patients were enrolled, comprised of 14 pituitary adenomas, 8 meningiomas, and 4 vestibular schwannomas. All patients demonstrated increased time spent at home, fewer number of significant locations visited, decreased walking time, and decreased total steps in the immediate post-operative period. For pituitaries, mean return to baseline for these variables was 25.7, 24.3, 80.2, and 88.9 days, respectively. For meningiomas, return to baseline was 56.5, 214.4, 45.0, and 45.6 days, respectively. For vestibular schwannomas, return to baseline was 219, 39.9, 35.1, and 36.4 days, respectively. This study demonstrates initial efficacy of digital phenotyping for a cohort of patients undergoing surgical resection of skull base lesions, based on passively collected smartphone GPS data during the peri-operative period. This is part of a larger, ongoing study enrolling surgical patients as well as non-operative controls for comparison. Such peri-operative mobility metrics may potentially be refined to predict postoperative outcomes following surgery such as improvement of neurological symptoms, postoperative CSF leak, infection, dysnatremia, and hospital length of stay.

Tailings storage facilities in China: historical failure incidents, existing status, and database-driven quantitative risk assessment

Tailings storage facility (TSF) failures in China have historically resulted in downstream consequences, including fatalities, economic harm, and environmental contamination. However, the nation-wide documentation on existing TSFs is incomplete, and the magnitude-frequency statistics of the failures are poorly quantified. These gaps have impeded ongoing efforts of risk assessment and mitigation. This study collates and analyzes new databases on historical TSF failures and existing TSFs in China. We report 143 TSF failures in China over the period 1957-2023, which exceeds the number (∼20) reported in previous studies. Magnitude-frequency statistics indicate that the mean return period for TSF failures in China with at least 10 fatalities is ∼5 years, while for those with released volumes >1 million m3 is ∼16 years. Our review confirms that there are at least 14,217 existing TSFs in China; therefore, the cumulative failure rate of TSFs in China is estimated to be ∼1%. We supply a database of 1,853 TSFs that lists the statistics such as storage volume and dam height. Using these datasets along with downstream demographic statistics, we undertake a regional risk assessment for Jilin Province, which identifies 11 TSFs with intolerable risks. Among these, the most critical TSF poses a potential loss of 175 lives. Our findings provide the most comprehensive picture of TSFs in China to date. We anticipate that this study will advance tailings disclosure practices in China and support screening-level risk assessments by provincial regulators to help prioritize community engagement and risk mitigation efforts.

Multivariate Regression Analysis of the Impact of Open Market Share Repurchase Activity on the Malaysian Market

This research thesis revolves around the need to understand the relationship between share repurchases and the share price behavior of companies listed on Bursa Malaysia on a more recent basis given the economic stability in Malaysia and throughout the world from 2017 to 2021. It started in the West and reached maturity in the 1980s in the United States, but it only began in Malaysia in the 1990s. The studies of share repurchase are still considered an infant in Malaysia as in other countries throughout the world, companies pursue share repurchases for several reasons mainly to signal undervaluation, reward shareholders, defend against the takeover, utilize financial resources efficiently, and many more motives that are interesting for researchers to look at. Unlike other studies that look at announcement dates, since an announcement does not mean the companies will implement the transactions, this research is important since it looks at and analyzes the actual effective repurchase day done by established firms which is are most crucial aspect in analyzing the consequences and the results are that it shows positive abnormal mean returns for most of the companies. Event study methodology was used since this is the best empirical research method and as empirical evidence to analyze abnormal returns from all the other studies. The days observed are 120 days before and after the announcement. Returns for the estimation window, event window (repurchase day), and post-event window were analyzed to see the effects of price movement on repurchase activities at Bursa Malaysia (BSKL).

First Hitting Times on a Quantum Computer: Tracking vs. Local Monitoring, Topological Effects, and Dark States.

We investigate a quantum walk on a ring represented by a directed triangle graph with complex edge weights and monitored at a constant rate until the quantum walker is detected. To this end, the first hitting time statistics are recorded using unitary dynamics interspersed stroboscopically by measurements, which are implemented on IBM quantum computers with a midcircuit readout option. Unlike classical hitting times, the statistical aspect of the problem depends on the way we construct the measured path, an effect that we quantify experimentally. First, we experimentally verify the theoretical prediction that the mean return time to a target state is quantized, with abrupt discontinuities found for specific sampling times and other control parameters, which has a well-known topological interpretation. Second, depending on the initial state, system parameters, and measurement protocol, the detection probability can be less than one or even zero, which is related to dark-state physics. Both return-time quantization and the appearance of the dark states are related to degeneracies in the eigenvalues of the unitary time evolution operator. We conclude that, for the IBM quantum computer under study, the first hitting times of monitored quantum walks are resilient to noise. However, a finite number of measurements leads to broadening effects, which modify the topological quantization and chiral effects of the asymptotic theory with an infinite number of measurements.

Comparative Performance Evaluation of Real Estate Investment Trusts Shares and Money Deposit Bank Shares in Nigeria (2013 – 2022)

This study presented a need to evaluate the investment performance of Real Estate Investment Trust shares and Money Deposit bank shares in Nigeria using dividend yields between 2013 to 2022. The aim of the study was to determine the mean annual dividend yields of both investment media and subsequently compare the relative performance so as to enable investors to make informed decisions about their choice of investment. The objectives of the study were to ascertain the dividend yield of both investment platforms over the last ten years, from 2013 to 2022 and to determine whether or not REIT shares outperformed Money Deposit Bank shares in dividend yield between 2013 to 2022.The methodology of data sample technique used was the purposive sampling technique, quantitative method of data collection was used to gather, assemble and collate data from the annual reports of selected of Real Estate Investment Trust and Money Deposit bank companies as well as through special publications of the Nigerian Stock Exchange (NSE) and Central Bank of Nigeria (CBN). Descriptive statistical techniques (Mean, standard deviation) were employed in analysing the data. The study found out that the performance of REITs shares showed a mean return of 5.275% over the ten years, this was compared to that of the performance of Money Deposit bank shares at 8.632% over the same ten years, showing under-performance. The study also found out that investments in Money Deposit Bank shares are much riskier than investment in REITs between 2013 to 2022. The study recommended that investment appraisal should be carried out before a decision is made towards embarking on such investment. It was also suggested that stakeholders in REIT should create an enabling environment for REIT to thrive in Nigeria.

Risk and Return Analysis of Stocks of Nepalese Commercial Banks

This research article analyzes the impact of risk and return of Nepalese commercial bank stocks on portfolio returns to assist investors in making informed investment decisions. It aims to examine the effects of individual bank stock returns, risks, market return, and market risk (beta) on overall portfolio performance. The study utilizes a quantitative approach, employing descriptive statistics, comparative (trend) analysis, correlation analysis, and hypothesis testing. Secondary data was collected from 18 commercial banks in Nepal, including post-merger banks, covering the fiscal years from 2015/16 to 2021/22. Statistical tools such as SPSS and EViews were used for analysis. The findings indicate that investors seeking higher returns might consider Prabhu Bank, which offers high mean returns but also comes with higher volatility. In contrast, risk-averse investors may prefer banks like NMB and Nabil, which provide lower mean returns but more stable performance. Notably, this research contributes to the understanding of the risk-return relationship in the context of 18 Nepalese commercial banks post-merger, providing new insights for investors. This study highlights the importance of analyzing individual bank stocks and their associated risks for portfolio construction. By understanding the dynamics of risk and return, investors can optimize their investment strategies and enhance portfolio performance. Overall, this research fills a gap in existing literature by focusing on the Nepalese commercial banking sector and its implications for investor decision-making. The insights gained from this study can guide investors in navigating the complexities of the stock market, ultimately leading to more informed and strategic investment choices. Future research could expand on this work by exploring additional factors influencing stock performance and investor behavior in the Nepalese context.

A Holocene fire history from Terra Nova National Park, Newfoundland, Canada: vegetation and climate change both influenced the fire regime

Fire is the largest natural disturbance factor in the boreal forest and plays a critical role in the composition, structure, and succession of stands and landscapes. The island of Newfoundland, located in eastern Canada, is subjected to a greater maritime influence, which may result in longer fire return intervals. The limited data on the fire regime does not account for interactions between fire, vegetation, and climate throughout the Holocene. We used sediment cores from Arnold’s Pond, Terra Nova National Park, which covered the last ~11,800 cal. yr BP, to investigate these interactions. We recognize 4 pollen zones and macroscopic charcoal analysis detected 45 local fire events. The 250-year mean fire return interval associated with the current vegetation is longer than a previous estimate for the park, but significantly shorter than other estimates for the island. Our mean fire return interval is within the range of fire estimates from Québec with similar vegetation. Our results suggest that the fire regime was primarily influenced by vegetation and climate. The transition to an open forest from a shrub tundra resulted in increased fire activity and fire frequency, which were likely driven by additional fuel on the landscape, but could have also been influenced by unknown climatic factors. We identified several examples of changes in the fire frequencies and/or charcoal accumulation that coincided with regional climate shifts, but we also identified a non-synchronous change. The non-synchronous shift to drier conditions resulted in a ~500-year time lag between peak Pinus strobus abundance and maximum fire frequency. Synchronous shifts in fire activity and/or fire frequency coincided with the 8200 event, Medieval Climate Anomaly and Little Ice Age. We also noted a decrease in fire frequency between 2600–1500 cal. yr BP that coincided with similar changes in the fire frequency from ~3000–1000 cal. yr BP in Québec. Our study highlights the complex interactions influencing the fire regime in our study area during the Holocene.

Projected gradient descent method for cardinality-constrained portfolio optimization

Cardinality-constrained portfolio optimization aims at determining the investment weights on given assets using the historical data. This problem typically requires three constraints, namely, capital budget, long–only, and sparsity. The sparsity restraint allows investment managers to select a small number of stocks from the given assets. Most existing approaches exploit the penalty technique to handle the sparsity constraint. Therefore, they require tweaking the associated regularization parameter to obtain the desired cardinality level, which is time-consuming. This paper formulates the sparse portfolio design as a cardinality-constrained nonconvex optimization problem, where the sparsity constraint is modeled as a bounded ℓ0-norm. The projected gradient descent (PGD) method is then utilized to deal with the resultant problem. Different from existing algorithms, the suggested approach, called ℓ0-PGD, can explicitly control the cardinality level. In addition, its convergence is established. Specifically, the ℓ0-PGD guarantees that the objective function value converges, and the variable sequences converges to a local minimum. To remedy the weaknesses of gradient descent, the momentum technique is exploited to enhance the performance of the ℓ0-PGD, yielding ℓ0-PMGD. Numerical results on four real-world datasets, viz. NASDAQ 100, S&P 500, Russell 1000, and Russell 2000 exhibit the superiority of the ℓ0-PGD and ℓ0-PMGD over existing algorithms in terms of mean return and Sharpe ratio.

Parsing the Performance of Stock Market Indices Amidst COVID-19 and Russia-Ukraine War: A Comparative Study of DSEX, Nifty-50, and KSE-100

The primary objective of this investigation is to assess the performance of the benchmark indices in the stock markets of Bangladesh, India, and Pakistan, denoted by DSEX (Dhaka Stock Exchange Broad Index), Nifty-50 (National Stock Exchange Fifty), and KSE-100 (Karachi Stock Exchange 100 Index), respectively. Data is meticulously gathered across distinct periods, namely the pre-COVID, the COVID-19, and the concurrent COVID-19 era along with the Russia-Ukraine War period, and amid the consequent global ongoing financial crises. The study encompasses information spanning from July 2, 2013 to May 9, 2023, employing descriptive statistics, where both mean returns and risk-adjusted returns were calculated consecutively. The evaluation of diversification among the indices during the specified periods is conducted through descriptive statistics and Ordinary Least Squares (OLS) estimation. The findings of this study indicate that all the indices exhibited negative mean returns during the COVID-19 phase. Furthermore, both mean returns and risk-adjusted returns of the indices witnessed substantial increments amid the inflationary environment concurrent with the COVID-19 and Russia-Ukraine War periods. OLS estimation results suggest an absence of a discernible diversification relationship among the indices. In summary, our results underscore the dynamic nature of index prices across diverse temporal and global crisis scenarios. These implications offer valuable insights for investors and stockholders, enabling them to discern hedging opportunities and identify diversifiable indices within the global stock markets across disparate periods and crises.

Risk-Based Asset Allocation in Factor Investing: Exploring the Inverse Factor Volatility Strategy

This study evaluates the effectiveness of the Inverse Factor Volatility strategy within the context of factor investing, comparing its performance to the conventional Risk Parity strategy. Using quantitative techniques, including portfolio construction and performance metrics analysis, this research employs data from five individual equities spanning the years 2000 to 2022. The methodology involves constructing portfolios based on Inverse Factor Volatility and Risk Parity principles and analyzing performance metrics, including mean returns, risk-adjusted returns, and drawdowns. The findings indicate that, compared to Risk Parity, Inverse Factor Volatility offers superior drawdowns, risk-adjusted returns, and mean returns. These results suggest that Inverse Factor Volatility may be a more effective strategy for portfolio management and could represent an advancement over traditional factor investing methods. The conclusions of this study hold significant implications for portfolio managers seeking to optimize their investment strategies.

ESG integration strategy with a multivariate normal distribution

Purpose: The paper aims to present a new framework for ESG integration strategies in portfolio optimization problems. The optimization in the new structure focuses on the portfolio level, and the procedure is not focused on utility functions or on preliminary weights applied to the asset level. It applies the resampling technique, and all the portfolios are optimal portfolios in the mean-variance space. It uses a filtering process where only optimal portfolios with lower ESG risks are considered. Therefore, this technique works only with optimized portfolios, avoids concentration bias, and considers estimation errors in the expected returns and in the covariance matrix. Design/methodology/approach: The sample mean returns and covariance matrices generated by a multivariate normal distribution are applied in mean-variance optimization to generate several portfolios in the efficient frontiers. An ESG filtering process is used to select portfolios with lower ESG risks from a sample of 42 companies listed on the Brazilian stock exchange with returns from the period of 2018/01/01 to 2024/04/22.Findings: Integration strategy costs may be lower than the best-in-class strategy costs and may be similar to the costs of a negative screening strategy. Social implications: The paper presents a framework that considers social, environmental, and governance factors in the portfolio optimization process.Originality: The main contribution of this paper is to present a new framework that combines resampling of returns’ mean and covariance based on a multivariate normal distribution with an ESG portfolio filtering process.

Metacarpal Stress Fractures in Athletes: A Systematic Review.

Stress fractures in general are common injuries; however, there is limited literature on metacarpal stress fractures in athletes. Our objective is to contribute the first systematic review of metacarpal stress fractures in athletes, with a particular focus on epidemiology, presentation, and outcomes. A systematic review regarding metacarpal stress fractures in athletes was performed via PubMed, EMBASE, MedLine, Cochrane, and Web of Science. Inclusion criteria consisted of case reports and case series of metacarpal stress fractures in athletes. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. A total of 11 studies (29 cases) were included. The mean patient age was 17 years, with 12 men and 15 women. The most common sports were tennis and badminton. The most common presentation was pain in the dorsal aspect of the hand related to activity. All patients underwent successful nonoperative management, with mean return to play of 9 weeks. Metacarpal stress fractures can present with significant pain and impact performance in athletes who perform sports involving repetitive movements of the hand and wrist. Nonoperative treatment, consisting of abstinence from sport until the patient was pain free combined with gradual return to play, was successful for all patients. The addition of proper technique and training load can result in satisfactory return to play. For patients who present with hand pain related to exercise, particularly a young racquet sport player, metacarpal stress fractures are a "can't miss" diagnosis associated with significant functional impairment.

Very Noisy Option Prices and Inference Regarding the Volatility Risk Premium

ABSTRACTThe stylized fact that volatility is not priced in individual equity options does not withstand scrutiny. First, we show that the average return of heavily traded deep out‐of‐the‐money call options on stocks is −116 basis points per day. Second, Fama‐MacBeth estimates of the volatility risk premium in stock options are similar to those in S&P 500 Index call options. Third, the mean return of heavily traded delta‐hedged at‐the‐money calls (puts) is −23 (−30) basis points. Fourth, the variance risk premium in stock options is negative. Our analysis highlights the importance of microstructure biases and robustness in empirical work with options.

Non-operative management of metacarpal II-IV fractures: A retrospective study from a tertiary hand unit

Metacarpal fractures produce significant hand disability, and non-operative management of these fractures can produce satisfactory functional outcomes with few complications. However, most studies assessing non-operative outcomes of metacarpal fractures revolves around metacarpals I and V, which possess different anatomy. Therefore, further investigation into outcomes after non-operative treatment of metacarpals II-IV is required to inform management decisions and allow modification of the rehabilitation protocols to specific fracture patterns. All records for 76 non-operative patients presenting with fractures of metacarpals II-IV to our tertiary centre in the year 2019 were retrospectively reviewed. Patients were treated with thermoplastic splinting or fibreglass casting with a rehabilitative exercise programme. Range of motion (ROM) of the Metacarpophalangeal (MCPJ), Proximal Interphalangeal (PIPJ), and Distal Interphalangeal joints (DIPJ), return to work time, and complications were assessed at 12 weeks post-treatment. Mean return to work time was 5.4 weeks, and patients did not report any serious adverse events; the main complication reported was tenderness on palpation (20%). The MCPJ exhibited the poorest ROM (9° flexion reduction relative to the healthy hand). Metacarpal II fractures were associated with significantly worse MCPJ flexion than metacarpal III (p=0.022) and metacarpal IV (p=0.049) fractures. Fractures of the metacarpal base were associated with superior MCPJ flexion (p=0.004) but longer return to work time (p=0.042) than head fractures. Spiral fractures were associated with shorter return to work time (p=0.043) and superior ROM results (p=0.041). In conclusion, outcomes of the non-operative treatment of metacarpal II-IV fractures are highly dependent on the location and pattern of the fracture, and this should be considered during clinical decision making.

Laparoscopic versus Open Appendectomy in Appendicitis Cases (Retrospective Comparative Study)

Abstract Background Appendectomy is one of the most commonly performed surgeries worldwide. It is commonly done by conventional open method but with progress of laparoscopic surgical procedures, laparoscopic appendectomy is also practiced nowadays. Ever since its initial description by Semm in 1983, laparoscopic appendectomy has struggled to prove its superiority over the open technique. The concept of minimal surgical trauma, resulting in significantly shorter hospital stay, less postoperative pain, faster return to daily activities has made laparoscopic surgery for acute appendicitis very attractive Objective To compare the intraoperative and post operative outcomes of laparoscopic versus open appendectomies for Appendicitis cases. Patients and Methods This study was done from April 2022 to September 2022 on 60 patients with clinical diagnosis of acute appendicitis admitted in surgical wards of Aldemerdash hospital. The patients were selected by random sampling technique. All the patients were followed every day in post operative period till they were discharged and then later followed for a period of 4 weeks in and out patients department. Results In the study, 8 patients in open group (26.7%) and 4 patients in laparoscopic group (13.3%) have post op fever. In the study, 8 patients in open group (26.7%) and 1 patients in laparoscopic group(3.3%) have post op wound infection. The difference was significant (p < 0.01) In the study, The mean hospital stay score was 1.77 ±0.728 days in the laparoscopic group and 7.73 ±1.363 days in the open group. The difference was significant (p < 0.0001). In the study, the mean score return to work was 9.6 days in laparoscopic and 17.67 days in the open group. The parameter difference was significant p < 0.0001 In the laparoscopic group, 26 (86.7%) patients were satisfied with cosmetic benefit, 4 (13.3%) patients were equivocally satisfied, 0 patients were unsatisfied. Conclusion We conclude that laparoscopic appendectomy is better than open appendectomy in respect to post operative pain, post operative complications, duration of the hospital stay, return to the work, cosmetic benefit. Duration of time of surgery is higher in laparoscopic compared to open appendectomy.

Laparoscopic versus Open Appendectomy in Appendicitis Cases (Retrospective Comparative Study)

Abstract Background Appendectomy is one of the most commonly performed surgeries worldwide. It is commonly done by conventional open method but with progress of laparoscopic surgical procedures, laparoscopic appendectomy is also practiced nowadays. Ever since its initial description by Semm in 1983, laparoscopic appendectomy has struggled to prove its superiority over the open technique. The concept of minimal surgical trauma, resulting in significantly shorter hospital stay, less postoperative pain, faster return to daily activities has made laparoscopic surgery for acute appendicitis very attractive. Objective To compare the intraoperative and post operative outcomes of laparoscopic versus open appendectomies for Appendicitis cases. Patients and Methods This study was done from April 2022 to September 2022 on 60 patients with clinical diagnosis of acute appendicitis admitted in surgical wards of Aldemerdash hospital. The patients were selected by random sampling technique. All the patients were followed every day in post operative period till they were discharged and then later followed for a period of 4 weeks in and out patients department. Results In the study, 8 patients in open group (26.7%) and 4 patients in laparoscopic group (13.3%) have post op fever. In the study, 8 patients in open group (26.7%) and 1 patients in laparoscopic group(3.3%) have post op wound infection. The difference was significant (p < 0.01) In the study, The mean hospital stay score was 1.77 ± 0.728 days in the laparoscopic group and 7.73 ±1.363 days in the open group. The difference was significant (p < 0.0001). In the study, the mean score return to work was 9.6 days in laparoscopic and 17.67 days in the open group. The parameter difference was significant p < 0.0001 In the laparoscopic group, 26 (86.7%) patients were satisfied with cosmetic benefit, 4 (13.3%) patients were equivocally satisfied, 0 patients were unsatisfied. Conclusion We conclude that laparoscopic appendectomy is better than open appendectomy in respect to post operative pain, post operative complications, duration of the hospital stay, return to the work, cosmetic benefit. Duration of time of surgery is higher in laparoscopic compared to open appendectomy.

Stock price overreaction: evidence from bull and bear markets

PurposeIn this paper, we provide new evidence to strengthen the stock market overreaction hypothesis by examining a new context that has not been explored before. Our research is inspired by the widely held belief that investor sentiment experiences abrupt changes from optimism to pessimism as the market switches between bull and bear states.Design/methodology/approachIf the stock market overreaction hypothesis is correct, it implies that investors are inclined to become excessively optimistic during bull markets and overly pessimistic during bear markets, resulting in overreaction and subsequent market correction. Consequently, the study first develops two testable hypotheses that can be used to uncover the presence of stock market overreaction with subsequent correction. These hypotheses are then tested using long-term data from the US market.FindingsThe study's findings support the hypothesis while also revealing a significant asymmetry in investor overreaction between bull and bear markets. Specifically, our results indicate that investors tend to overreact towards the end of a bear market, and the subsequent bull market starts with a prompt and robust correction. Conversely, investors appear to overreact only towards the end of a prolonged bull market. The correction during a bear market is not confined to its initial phase but extends across its entire duration.Research limitations/implicationsOur study has some limitations related to its focus on investigating stock market overreaction in the US market and analyzing the pattern of mean returns during bull and bear market states. Expanding our study to different global markets would be necessary to understand whether the same stock market overreaction effect exists universally. Furthermore, exploring the relationship between volatility and overreaction during different market phases would be an exciting direction for future research, as it could provide a more complete picture of market dynamics.Practical implicationsOur study confirms the presence of the stock market overreaction effect, which contradicts the efficient market hypothesis. We have observed specific price patterns during bull and bear markets that investors can potentially exploit. However, successfully capitalizing on these patterns depends on accurately predicting the turning points between bull and bear market states.Social implicationsThe results of our study have significant implications for market regulators. Stock market overreactions resulting in market corrections can severely disrupt the market, leading to significant financial losses for investors and undermining investor confidence in the overall market. Further, the existence of overreactions suggests that the stock market may not always be efficient, raising regulatory concerns. Policymakers and regulators may need to implement policies and regulations to mitigate the effects of overreactions and subsequent market corrections.Originality/valueThis paper aims to provide additional support for the stock market overreaction hypothesis using a new setting in which this hypothesis has not been previously investigated.

A Re-examination of Housing Investment Performance in Nigeria

Arising from the lack of a holistic performance analysis of housing investment in Nigeria, this paper re-examines the return-risk performance of residential property assets by focusing on the tier 1 property markets of Lagos, Abuja, and Port Harcourt. Data on the rental and capital values of residential property assets, comprising bungalows, blocks of flats, and detached houses, from 1999 to 2022 were obtained from estate surveying and valuation firms in the three locations. Mean return and standard deviation were employed to analyse return and risk profiles. Variations in return and risk profiles were further examined using a four-year sub-period analysis. The return-risk ratio was also employed to measure the attractiveness of the investment. The downside risk measure of the Sortino ratio was utilised to determine the risk-adjusted performance of the residential property assets. The results revealed that, on mean return and return-risk tradeoff bases, bungalow investments had superior performance compared with other property types across the geographic areas. When aggregated, residential property assets in Port Harcourt experienced superior return-risk performance relative to other locations. On sub-period analysis, the study established variations in the performance of the residential property assets across time periods and locations. On the risk-adjusted performance measure, it was found that bungalows in Lagos had the highest risk-adjusted performance. Detached house investments across the three locations were also found to exhibit low downside risk-adjusted performance. The study concluded that investors could gain high and attractive returns when making bungalow housing investment decisions with a huge potential for downside risk-proof returns. Moreover, investors could further expand this potential by concentrating more housing investment activities in Port Harcourt, as returns in this location are insulated from downside risk. However, investors should be cautious when investing in detached house assets across the three locations, as returns from this asset might be susceptible to downside risk.

COMPARISION OF LICHTESTEIN OPEN TENSION-FREE VERSUS LAPROSCOPIC TOTALLY EXTRAPERTIONEAL TECHNIQUE FOR INGUINAL HERNIA REPAIR

Objectives: The study aimed to assess and compare Litchtenstein’s open tension-free and laparoscopic totally extraperitoneal (TEP) mesh repair. Methods: This hospital-based comparative type of observational study was conducted on 50 cases for each of two groups at upgraded Department of General Surgery, SMS Hospital, Jaipur, between January 2014 and January 2016. All the cases of elective inguinal hernia coming to SMS outpatient department in a single surgical unit operated by a single surgeon in the given period which meet the inclusion and exclusion criteria. Thus, collected data were entered in Microsoft Excel sheet and analysis was done by Epi info software of CDC. Results: Total 100 patients were included in this study; 50 each in the two groups, the laparoscopic TEP group and open Lichtenstein group. Mean age in the laparoscopic group was 39.54 years and the open Lichtenstein group was 42.78 years. The mean pain score out of 10 at 24 h was 2.96 (±0.638) and 3.60 (±0.969) in TEP and Lichtenstein groups, respectively. The mean return to work for open group was 17.00 and TEP group was 11.34 days. There is no any recurrence and readmission in both groups. Conclusion: Laparoscopic TEP repair may be done in all uncomplicated inguinal hernia by an experienced surgeon for those desiring less pain, better cosmotic results, less post-operative complications, less hospital stay, and early return to work.

The analysis of diversification properties of stablecoins through the Shannon entropy measure

The common goal for investors is to minimise the risk and maximise the returns on their investments. This is often achieved through diversification, where investors spread their investments across various assets. This study aims to use the MAD-entropy model to minimise the absolute deviation, maximise the mean return, and maximise the Shannon entropy of the portfolio. The MAD model is used because it is a linear programming model, allowing it to resolve large-scale problems and nonnormally distributed data. Entropy is added to the MAD model because it can better diversify the weight of assets in the portfolios. The analysed portfolios consist of cryptocurrencies, stablecoins, and selected world indices such as the SP500 and FTSE obtained from Yahoo Finance. The models found that stablecoins pegged to the US dollar, followed by stablecoins pegged to gold, are better diversifiers for traditional cryptocurrencies and stocks. These results are probably due to their low volatility compared to the other assets. Findings from this study may assist investors since the MAD-Entropy model outperforms the MAD model by providing more significant portfolio mean returns with minimal risk. Therefore, crypto investors can design a well-diversified portfolio using MAD entropy to reduce unsystematic risk. Further research integrating mad entropy with machine learning techniques may improve accuracy and risk management.