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To assess the efficacy of a transmission‐type parallel plane reference chamber (T‐REF) for small‐field percentage depth dose (PDD) measurements using two high‐resolution detectors. The study utilizes microSilicon and microDiamond detectors for small‐field measurements, both with and without a T‐REF reference chamber. TrueBeam linear accelerator provides various photon energies (6X, 6XFFF, 10X, 10XFFF) for depth dose measurements. A sun‐nuclear 3D water tank is used to measure the PDD up to a depth of 15 cm. Analysis of the data includes a 1D gamma passing rate calculated using an in‐house MATLAB program. The study compares the PDD measurements obtained with and without the T‐REF. The T‐REF exhibits negligible beam perturbations across different field sizes and energies. The overall maximum mean PDD differences are 0.31 ± 0.16% for microSilicon and 0.33 ± 0.17% for microdiamond. The overall mean 1D gamma passing rate is 99.6 ± 0.2%. This study demonstrates that the T‐REF is a reliable and effective reference detector for small‐field radiation dosimetry. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to examine the impact of bankruptcy reform in the year 2016 on the relation between leverage and firm performance for Indian firms, separately for business group and standalone firms. Design/methodology/approach: Fixed effects panel regression is used to understand the role of bankruptcy reform on firm-level data to examine the relationship between leverage and firm performance after controlling for size, growth, age, liquidity and promoter shareholding. The authors also apply the generalized method of moments (GMM) to control for the endogeneity concerns. Findings: The authors show that the introduction of the insolvency and bankruptcy code (IBC) positively moderates the relation between leverage and firm performance such that the extent of negative relation between leverage and firm performance is less in the post-IBC period. The positive impact of IBC on the relation between leverage and firm performance holds only for firms not affiliated to business groups and for firms with higher debt in their capital structure. Practical implications: The study's findings will help the regulators appreciate the effectiveness of bankruptcy reforms resulting from IBC implementation in terms of sound bankruptcy process and leading to safeguard the interests of minority shareholders. Originality/value: The authors provide the only study to examine the role of bankruptcy law in moderating the relation between leverage and firm performance across a sample of business group and standalone firms. [ABSTRACT FROM AUTHOR]

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Residents begin their training as an extension of surgeons' hands and end with the assurance they have safe hands. The results of this project will identify needs in the technical skills training of future cardiac surgery residents. We sought to report the capabilities of residents to identify femoral landmarks and the native anterior cruciate ligament (ACL) footprint before and after a structured formal teaching session performed in fall 2018 as a reflection of overall surgical skills training for orthopedic surgery residents in Canada. Among the 188 survey respondents were 77 students, 56 surgeons, 24 residents, 17 nurses and 14 anesthesiologists. Further evaluation of groups that were more positively affected by their UGME anatomy training, such as general surgery and orthopedic surgery residents, may elicit strategies to enhance medical students' interest in surgery. [Extracted from the article]

Purpose: The purpose of this study was to evaluate the dosimetric impact of multileaf collimator (MLC) positional errors on dynamic intensity-modulated radiotherapy (IMRT) treatments through planning simulation. Secondly the sensitivity of IMRT MatriXX device for detecting the MLC leaf positional errors was also evaluated. Materials and methods: In this study five dynamic IMRT plans, each for brain and head–neck (HN), were retrospectively included. An in-house software was used to introduce random errors (uniform distribution between −2·0 and +2·0 mm) and systematic errors [±0·5, ±0·75, ±1·0 and ±2·0 mm (+: open MLC error and −: close MLC error)]. The error-introduced MLC files were imported into the treatment planning system and new dose distributions were calculated. Furthermore, the dose–volume histogram files of all plans were exported to in-house software for equivalent uniform dose (EUD), tumour control probability and normal tissue complication probability calculations. The error-introduced plans were also delivered on LINAC, and the planar fluences were measured by IMRT MatriXX. Further, 3%/3 mm and 2%/2 mm γ -criteria were used for analysis. Results: In planning simulation study, the impact of random errors was negligible and ΔEUD was <0·5±0·7%, for both brain and HN. The impact of systematic errors was substantial, and on average, the maximum change in EUD for systematic errors (close 2 mm) was −10·7±3·1% for brain and −15·5±2·6% for HN. Conclusions: It can be concluded that the acceptable systematic error was 0·4 mm for brain and 0·3 mm for HN. Furthermore, IMRT MatriXX device was able to detect the MLC errors ≥2 mm in HN and >3 mm errors in brain with 2%/2 mm γ -criteria. [ABSTRACT FROM AUTHOR]

Purpose: With the advent of state-of-the-art treatment technologies, the use of small fields has increased, and dosimetry in small fields is highly challenging. In this study, the potential use of Varian electronic portal imaging device (EPID) for small field measurements was explored for 6 and 15 MV photon beams. Materials and Methods: The output factors and profiles were measured for a range of jaw-collimated square field sizes starting from 0.8 cm × 0.8 cm to 10 cm × 10 cm using EPID. For evaluation purpose, reference data were acquired using Exradin A16 microionization chamber (0.007 cc) for output factors and stereotactic field diode for profile measurements in a radiation field analyzer. Results: The output factors of EPID were in agreement with the reference data for field sizes down to 2 cm × 2 cm and for 2 cm × 2 cm; the difference in output factors was +2.06% for 6 MV and +1.56% for 15 MV. For the lowest field size studied (0.8 cm × 0.8 cm), the differences were maximum; +16% for 6 MV and +23% for 15 MV photon beam. EPID profiles of both energies were closely matching with reference profiles for field sizes down to 2 cm × 2 cm; however, penumbra and measured field size of EPID profiles were slightly lower compared to its counterpart. Conclusions: EPID is a viable option for profile and output factor measurements for field sizes down to 2 cm × 2 cm in the absence of appropriate small field dosimeters. [ABSTRACT FROM AUTHOR]

The paper explores the lead-lag relationship between the variables of order imbalance and return in futures and spot markets. Order imbalance is defined as the difference between buyer and seller initiated trades. Using tick test, the trades have been classified as buyer and seller initiated. The paper finds positive correlation between the variables of order imbalance in the futures market and the returns in the spot market. This relationship is further explored using a VAR framework for daily as well as a shorter interval of 120 min. The results reveal that even after controlling for lagged futures and spot returns, the futures market imbalance has a significant effect on spot market returns. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to study the empirical relationship between order imbalance and returns in the backdrop of structural changes in the Indian market. Design/methodology/approach – The study makes use of hypothesis testing and dummy variable regression to investigate the relationship between order imbalance and returns during the period 1999-2005, which saw definitive change in the structure of the Indian markets. Findings – Order imbalance (buying or selling pressure) has significantly reduced post the structural reforms at the daily as well as intra-day intervals across trade, as well as value measures of order imbalance. After controlling for the number of transactions, order imbalance and return correlations have fallen in the post-2002 period as compared to the pre-2002 period, at daily as well as intra-day intervals. Further, after controlling for past high and low returns, order imbalance exhibits day of the week effect in the pre-2002 period while no such effect is seen in the post-2002 period. Originality/value – The work brings out order imbalance and returns relationship for the Indian market, which has different structure from that of many developed, as well as developing, markets in the backdrop of changes in its own structure. This would provide a richer literature in the area of market structure and design. [ABSTRACT FROM AUTHOR]

This study investigates the informational role of options open interests and volume in predicting the future stock prices in Indian market. Most of the time, the uninformed traders lose to informed traders because they neither have private information nor the sophisticated knowledge to process the publicly available information. The most closely watched data are also the least informative. This study is an attempt to find out if the daily published and publicly available options data are informative and can be used to forecast the future stock price at maturity. Then the retail traders and investors will be able to minimize their loss to informed traders and enhance their portfolio performance. The sample of this study is 17 highly traded Nifty 50 index stocks from different sectors having significant share in the index. Predictors based on options price and options volume have been estimated, following Bhuyan and Williams (2004), and then used in the regression model as predictor variables of price at maturity both jointly and in isolation. The period of study covers stock options contract of three months (July-September 2009). Only near month contract is considered for the study because of liquidity concern. The coefficients of predictors are found to be significant and not statistically different across the study period. Consistent with the results of the previous studies, the results show that options open interest and volume are relevant in forecasting future prices. [ABSTRACT FROM AUTHOR]