In order to elucidate the role of antioxidant responses in salinity tolerance in rice genotypes under salt stress, experiments were conducted using four rice varieties, including salt-sensitive BRRI dhan 28 and three ...In order to elucidate the role of antioxidant responses in salinity tolerance in rice genotypes under salt stress, experiments were conducted using four rice varieties, including salt-sensitive BRRI dhan 28 and three salt-tolerant varieties BRRI dhan 47, BINA dhan 8 and BINA dhan 10. Thirty-day-old rice seedlings were transplanted into pots. At the active tillering stage(35 d after transplanting), plants were exposed to different salinity levels(0, 20, 40 and 60 mmol/L NaCl). Salt stress caused a significant reduction in growth for all the rice genotypes. Growth reduction was higher in the salt-sensitive genotype than in the salt-tolerant ones, and BINA dhan 10 showed higher salt tolerance in all measured physiological parameters. The reduction in shoot and root biomass was found to be minimal in BINA dhan 10. Chlorophyll content significantly decreased under salt stress except for BINA dhan 10. Proline content significantly increased in salt-tolerant rice genotypes with increased salt concentration, and the highest proline content was obtained from BINA dhan 10 under salt stress. Catalase and ascorbate peroxidase activities significantly decreased in salt-sensitive genotype whereas significantly increased in salt-tolerant ones with increasing salt concentration. However, salt stress significantly decreased guaiacol peroxidase activity in all the rice genotypes irrespective of salt tolerance. K^+/Na^+ ratio also significantly decreased in shoots and roots of all the rice genotypes. The salt-tolerant genotype BINA dhan 10 maintained higher levels of chlorophyll and proline contents as well as catalase and ascorbate peroxidase activities under salt stress, thus, this might be the underlying mechanism for salt tolerance.展开更多
The Internet of Medical Things(IoMT)offers an infrastructure made of smart medical equipment and software applications for healthcare services.Through the internet,the IoMT is capable of providing remote medical diagn...The Internet of Medical Things(IoMT)offers an infrastructure made of smart medical equipment and software applications for healthcare services.Through the internet,the IoMT is capable of providing remote medical diagnosis and timely health services.The patients can use their smart devices to create,store and share their electronic health records(EHR)with a variety of medical personnel including medical doctors and nurses.However,unless the underlying commination within IoMT is secured,malicious users can intercept,modify and even delete the sensitive EHR data of patients.Patients also lose full control of their EHR since most healthcare services within IoMT are constructed under a centralized platform outsourced in the cloud.Therefore,it is appealing to design a decentralized,auditable and secure EHR system that guarantees absolute access control for the patients while ensuring privacy and security.Using the features of blockchain including decentralization,auditability and immutability,we propose a secure EHR framework which is mainly maintained by the medical centers.In this framework,the patients’EHR data are encrypted and stored in the servers of medical institutions while the corresponding hash values are kept on the blockchain.We make use of security primitives to offer authentication,integrity and confidentiality of EHR data while access control and immutability is guaranteed by the blockchain technology.The security analysis and performance evaluation of the proposed framework confirms its efficiency.展开更多
The rapid development of personal health records(PHR)systems enables an individual to collect,create,store and share his PHR to authorized entities.Health care systems within the smart city environment require a patie...The rapid development of personal health records(PHR)systems enables an individual to collect,create,store and share his PHR to authorized entities.Health care systems within the smart city environment require a patient to share his PRH data with a multitude of institutions’repositories located in the cloud.The cloud computing paradigm cannot meet such a massive transformative healthcare systems due to drawbacks including network latency,scalability and bandwidth.Fog computing relieves the load of conventional cloud computing by availing intermediate fog nodes between the end users and the remote servers.Assuming a massive demand of PHR data within a ubiquitous smart city,we propose a secure and fog assisted framework for PHR systems to address security,access control and privacy concerns.Built under a fog-based architecture,the proposed framework makes use of efficient key exchange protocol coupled with ciphertext attribute based encryption(CP-ABE)to guarantee confidentiality and fine-grained access control within the system respectively.We also make use of digital signature combined with CP-ABE to ensure the system authentication and users privacy.We provide the analysis of the proposed framework in terms of security and performance.展开更多
This paper examines the effect of Korea's fair disclosure regulation on the timeliness and informativeness of earnings announcements. The present regulation for Korean listed firms requires that if a company's...This paper examines the effect of Korea's fair disclosure regulation on the timeliness and informativeness of earnings announcements. The present regulation for Korean listed firms requires that if a company's sales revenue, operating income(or loss) and net income(or loss) have changed by over 30%compared to the prior year, the firm must disclose this information through a preliminary financial report(PFR) even before the company is audited by external auditors. To analyze the effects of this policy, we first investigate the timeliness of preliminary financial report disclosures. We examine the extent to which Korean listed companies actually comply with the requirement for prompt notification of information concerning material changes in financial performance. Second, we investigate the informativeness of preliminary financial reports by analyzing differential stock market reactions to different timings of preliminary financial report disclosures. Our empirical results reveal that more than half of our sample firms release their preliminary financialreports after external audits are completed, thereby potentially invalidating the effectiveness of the regulation. In addition, we find that preliminary financial reports have information value only if they are disclosed prior to annual audit report dates. This finding supports the notion that timeliness increases the informativeness of preliminary financial report disclosure by curbing insiders' ability to potentially profit from their information advantage.展开更多
基金supported by a grant from the Ministry of Education, Government of Bangladesh
文摘In order to elucidate the role of antioxidant responses in salinity tolerance in rice genotypes under salt stress, experiments were conducted using four rice varieties, including salt-sensitive BRRI dhan 28 and three salt-tolerant varieties BRRI dhan 47, BINA dhan 8 and BINA dhan 10. Thirty-day-old rice seedlings were transplanted into pots. At the active tillering stage(35 d after transplanting), plants were exposed to different salinity levels(0, 20, 40 and 60 mmol/L NaCl). Salt stress caused a significant reduction in growth for all the rice genotypes. Growth reduction was higher in the salt-sensitive genotype than in the salt-tolerant ones, and BINA dhan 10 showed higher salt tolerance in all measured physiological parameters. The reduction in shoot and root biomass was found to be minimal in BINA dhan 10. Chlorophyll content significantly decreased under salt stress except for BINA dhan 10. Proline content significantly increased in salt-tolerant rice genotypes with increased salt concentration, and the highest proline content was obtained from BINA dhan 10 under salt stress. Catalase and ascorbate peroxidase activities significantly decreased in salt-sensitive genotype whereas significantly increased in salt-tolerant ones with increasing salt concentration. However, salt stress significantly decreased guaiacol peroxidase activity in all the rice genotypes irrespective of salt tolerance. K^+/Na^+ ratio also significantly decreased in shoots and roots of all the rice genotypes. The salt-tolerant genotype BINA dhan 10 maintained higher levels of chlorophyll and proline contents as well as catalase and ascorbate peroxidase activities under salt stress, thus, this might be the underlying mechanism for salt tolerance.
文摘The Internet of Medical Things(IoMT)offers an infrastructure made of smart medical equipment and software applications for healthcare services.Through the internet,the IoMT is capable of providing remote medical diagnosis and timely health services.The patients can use their smart devices to create,store and share their electronic health records(EHR)with a variety of medical personnel including medical doctors and nurses.However,unless the underlying commination within IoMT is secured,malicious users can intercept,modify and even delete the sensitive EHR data of patients.Patients also lose full control of their EHR since most healthcare services within IoMT are constructed under a centralized platform outsourced in the cloud.Therefore,it is appealing to design a decentralized,auditable and secure EHR system that guarantees absolute access control for the patients while ensuring privacy and security.Using the features of blockchain including decentralization,auditability and immutability,we propose a secure EHR framework which is mainly maintained by the medical centers.In this framework,the patients’EHR data are encrypted and stored in the servers of medical institutions while the corresponding hash values are kept on the blockchain.We make use of security primitives to offer authentication,integrity and confidentiality of EHR data while access control and immutability is guaranteed by the blockchain technology.The security analysis and performance evaluation of the proposed framework confirms its efficiency.
基金the Deanship of Scientific Research at King Saud University for funding this work through Vice Deanship of Scientific Research Chairs:Chair of Pervasive and Mobile Computing.
文摘The rapid development of personal health records(PHR)systems enables an individual to collect,create,store and share his PHR to authorized entities.Health care systems within the smart city environment require a patient to share his PRH data with a multitude of institutions’repositories located in the cloud.The cloud computing paradigm cannot meet such a massive transformative healthcare systems due to drawbacks including network latency,scalability and bandwidth.Fog computing relieves the load of conventional cloud computing by availing intermediate fog nodes between the end users and the remote servers.Assuming a massive demand of PHR data within a ubiquitous smart city,we propose a secure and fog assisted framework for PHR systems to address security,access control and privacy concerns.Built under a fog-based architecture,the proposed framework makes use of efficient key exchange protocol coupled with ciphertext attribute based encryption(CP-ABE)to guarantee confidentiality and fine-grained access control within the system respectively.We also make use of digital signature combined with CP-ABE to ensure the system authentication and users privacy.We provide the analysis of the proposed framework in terms of security and performance.
文摘This paper examines the effect of Korea's fair disclosure regulation on the timeliness and informativeness of earnings announcements. The present regulation for Korean listed firms requires that if a company's sales revenue, operating income(or loss) and net income(or loss) have changed by over 30%compared to the prior year, the firm must disclose this information through a preliminary financial report(PFR) even before the company is audited by external auditors. To analyze the effects of this policy, we first investigate the timeliness of preliminary financial report disclosures. We examine the extent to which Korean listed companies actually comply with the requirement for prompt notification of information concerning material changes in financial performance. Second, we investigate the informativeness of preliminary financial reports by analyzing differential stock market reactions to different timings of preliminary financial report disclosures. Our empirical results reveal that more than half of our sample firms release their preliminary financialreports after external audits are completed, thereby potentially invalidating the effectiveness of the regulation. In addition, we find that preliminary financial reports have information value only if they are disclosed prior to annual audit report dates. This finding supports the notion that timeliness increases the informativeness of preliminary financial report disclosure by curbing insiders' ability to potentially profit from their information advantage.
