Using daily BTC-USD data from September 19,2014 to January 21,2024,this paper re-examines whether weekends differ from weekdays for Bitcoin along three margins:average returns,close-to-close volatility,and trading act...Using daily BTC-USD data from September 19,2014 to January 21,2024,this paper re-examines whether weekends differ from weekdays for Bitcoin along three margins:average returns,close-to-close volatility,and trading activity.We implement Welch mean comparisons and HAC-robust OLS with month fixed effects(bandwidths 5,7,and 14).In the full sample and across subsamples(2016–2019;2020–2023;early 2024),we find no detectable weekend–weekday gap in average returns,while volatility and trading activity are lower on weekends.The patterns are robust to using squared returns as a volatility proxy.The joint evidence is consistent with liquidity and attention mechanisms—quieter weekends rather than compensating return premia.Replication files reproduce all tables and figures.展开更多
AIM:To evaluate whether weekend or nighttime admission affects prognosis of peptic ulcer bleeding despite early endoscopy.METHODS:Retrospective data collection from four referral centers,all of which had a formal out-...AIM:To evaluate whether weekend or nighttime admission affects prognosis of peptic ulcer bleeding despite early endoscopy.METHODS:Retrospective data collection from four referral centers,all of which had a formal out-of-hours emergency endoscopy service,even at weekends.A total of 388 patients with bleeding peptic ulcers who were admitted via the emergency room between January 2007 and December 2009 were enrolled.Analyzed parameters included time from patients' arrival until endoscopy,mortality,rebleeding,need for surgery and length of hospital stay.RESULTS:The weekday and weekend admission groups comprised 326 and 62 patients,respectively.There were no significant differences in baseline characteristics between the two groups,except for younger age in the weekend group.Most patients (97%) had undergone early endoscopy,which resulted in a low mortality rate regardless of point of presentation (1.8% overall vs 1.6% on the weekend).The only outcome that was worse in the weekend group was a higher rate of rebleeding (12% vs 21%,P = 0.030).However,multivariate analysis revealed nighttime admission and a high Rockall score (≥ 6) as significant independent risk factors for rebleeding,rather than weekend admission.CONCLUSION:Early endoscopy for peptic ulcer bleeding can prevent the weekend effect,and nighttime admission was identified as a novel risk factor for rebleeding,namely the nighttime effect.展开更多
This paper aims to examine the existence of calendar anomalies including month-of-year effect, turn-of-month effect, and weekend effect in Thai stock market. The stock return is computed from SET index during 1988 to ...This paper aims to examine the existence of calendar anomalies including month-of-year effect, turn-of-month effect, and weekend effect in Thai stock market. The stock return is computed from SET index during 1988 to 2009 and the SET50 index gathered since it was created in 1995. The unit root test is performed to ensure that the stock return series have no unit root. The multiple regression techniques using dummy variables are employed to test the difference of the return during each calendar anomalies period. If the regression model suffers from conditional heteroskedasticity, the GARCH （1, 1） model will be used instead of normal ordinary least square regression. It was found that the calendar anomalies exist in Thai stock market. The return is abnormally high during December and January, which can be addressed to be the turn-of-year effect. The return during the turn-of-month period, which can be defined as the last trading day and the first four trading days of the following months, is also abnormally high. Finally, the return is also abnormally high on Fridays but abnormally low on Mondays, which is addressed as weekend effect. This may create the opportunity to make above-average profit to investors exploiting these calendar anomalies. Although these calendar anomalies may be difficult to be exploited in practice because of transaction costs and ability to replicate the stock index, the existing evidence of calendar anomalies can help investors as the clue for the timing of investment.展开更多
Aims:To determine whether day and time of admission influences the practice patterns of the admitting general surgeon and subsequent outcomes for patients diagnosed with small bowel obstruction.Methods:A retrospective...Aims:To determine whether day and time of admission influences the practice patterns of the admitting general surgeon and subsequent outcomes for patients diagnosed with small bowel obstruction.Methods:A retrospective database review was carried out,covering patients admitted with the presumed diagnosis of partial small bowel obstruction from 2004–2011.Results:A total of 404 patients met the inclusion criteria.One hundred and thirty-nine were admitted during the day,93 at night and 172 on the weekend.Overall 30.2%of the patients were managed operatively with no significant difference between the groups(P=0.89);however,of patients taken to the operating room,patients admitted during the day received operative intervention over 24 hours earlier than those admitted at a weekend,0.79 days vs 1.90 days,respectively(P=0.05).Overall mortality was low at 1.7%,with no difference noted between the groups(P=0.35).Likewise there was no difference in morbidity rates between the three groups(P=0.90).Conclusions:Despite a faster time to operative intervention in those patients admitted during the day,our study revealed that time of admission does not appear to correlate to patient outcome or mortality.展开更多
文摘Using daily BTC-USD data from September 19,2014 to January 21,2024,this paper re-examines whether weekends differ from weekdays for Bitcoin along three margins:average returns,close-to-close volatility,and trading activity.We implement Welch mean comparisons and HAC-robust OLS with month fixed effects(bandwidths 5,7,and 14).In the full sample and across subsamples(2016–2019;2020–2023;early 2024),we find no detectable weekend–weekday gap in average returns,while volatility and trading activity are lower on weekends.The patterns are robust to using squared returns as a volatility proxy.The joint evidence is consistent with liquidity and attention mechanisms—quieter weekends rather than compensating return premia.Replication files reproduce all tables and figures.
文摘AIM:To evaluate whether weekend or nighttime admission affects prognosis of peptic ulcer bleeding despite early endoscopy.METHODS:Retrospective data collection from four referral centers,all of which had a formal out-of-hours emergency endoscopy service,even at weekends.A total of 388 patients with bleeding peptic ulcers who were admitted via the emergency room between January 2007 and December 2009 were enrolled.Analyzed parameters included time from patients' arrival until endoscopy,mortality,rebleeding,need for surgery and length of hospital stay.RESULTS:The weekday and weekend admission groups comprised 326 and 62 patients,respectively.There were no significant differences in baseline characteristics between the two groups,except for younger age in the weekend group.Most patients (97%) had undergone early endoscopy,which resulted in a low mortality rate regardless of point of presentation (1.8% overall vs 1.6% on the weekend).The only outcome that was worse in the weekend group was a higher rate of rebleeding (12% vs 21%,P = 0.030).However,multivariate analysis revealed nighttime admission and a high Rockall score (≥ 6) as significant independent risk factors for rebleeding,rather than weekend admission.CONCLUSION:Early endoscopy for peptic ulcer bleeding can prevent the weekend effect,and nighttime admission was identified as a novel risk factor for rebleeding,namely the nighttime effect.
文摘This paper aims to examine the existence of calendar anomalies including month-of-year effect, turn-of-month effect, and weekend effect in Thai stock market. The stock return is computed from SET index during 1988 to 2009 and the SET50 index gathered since it was created in 1995. The unit root test is performed to ensure that the stock return series have no unit root. The multiple regression techniques using dummy variables are employed to test the difference of the return during each calendar anomalies period. If the regression model suffers from conditional heteroskedasticity, the GARCH （1, 1） model will be used instead of normal ordinary least square regression. It was found that the calendar anomalies exist in Thai stock market. The return is abnormally high during December and January, which can be addressed to be the turn-of-year effect. The return during the turn-of-month period, which can be defined as the last trading day and the first four trading days of the following months, is also abnormally high. Finally, the return is also abnormally high on Fridays but abnormally low on Mondays, which is addressed as weekend effect. This may create the opportunity to make above-average profit to investors exploiting these calendar anomalies. Although these calendar anomalies may be difficult to be exploited in practice because of transaction costs and ability to replicate the stock index, the existing evidence of calendar anomalies can help investors as the clue for the timing of investment.
文摘Aims:To determine whether day and time of admission influences the practice patterns of the admitting general surgeon and subsequent outcomes for patients diagnosed with small bowel obstruction.Methods:A retrospective database review was carried out,covering patients admitted with the presumed diagnosis of partial small bowel obstruction from 2004–2011.Results:A total of 404 patients met the inclusion criteria.One hundred and thirty-nine were admitted during the day,93 at night and 172 on the weekend.Overall 30.2%of the patients were managed operatively with no significant difference between the groups(P=0.89);however,of patients taken to the operating room,patients admitted during the day received operative intervention over 24 hours earlier than those admitted at a weekend,0.79 days vs 1.90 days,respectively(P=0.05).Overall mortality was low at 1.7%,with no difference noted between the groups(P=0.35).Likewise there was no difference in morbidity rates between the three groups(P=0.90).Conclusions:Despite a faster time to operative intervention in those patients admitted during the day,our study revealed that time of admission does not appear to correlate to patient outcome or mortality.
