A coal burst occurred on 15 April, 2014 at the Austar Coal Mine, located west of Newcastle, NSW,Australia. The burst resulted in fatal injuries to two men working as part of the mining crew at the development face. At...A coal burst occurred on 15 April, 2014 at the Austar Coal Mine, located west of Newcastle, NSW,Australia. The burst resulted in fatal injuries to two men working as part of the mining crew at the development face. At the time, a continuous miner was being used to mine a longwall development gate road through heavily structured coal, at a depth of approximately 550 m. A number of pre-cursor bumps had occurred on previous shifts, emanating from the coal ribs of the roadway, in proximity to the coal face.This paper reviews the geological, geotechnical and mining conditions and circumstances leading up to the coal burst event; and presents and discusses the available evidence and possible interpretations relating to the geomechanical behaviour mechanisms that may have been critical factors in this incident. The paper also discusses some key technical and operational considerations of ground support systems and mining practices and strategies needed for operating in such conditions in the future.展开更多
The aim of this study is to investigate the effect of auditor type and eamings reporting lag on the cost of debt for the Tunisian setting. Our sample consists of 32 Tunisian companies for the period of 2003-2012. Audi...The aim of this study is to investigate the effect of auditor type and eamings reporting lag on the cost of debt for the Tunisian setting. Our sample consists of 32 Tunisian companies for the period of 2003-2012. Audit quality is measured by auditor size （Big 4 versus non-Big 4） and timely disclosure is proxied by earnings reporting lag. Results show that auditor type is negatively associated with the cost of debt. By contrast, the association between earnings announcement lag and the cost of debt is positive and significant. When testing for the moderating effects of industry and listing status, we document that these associations are more pronounced for industrial companies and listed firms. Finally, the period of investigation slightly moderates the examined associations, since financial institutions become more sensitive to the tardy communication of information and less concerned with auditor type following some economic and political troubles in Tunisia between 2010 and 2012. Our findings have policy implications for managers in the Tunisian setting and other developing economies similar to Tunisia given the crucial role played by debt as an important source of external finance for companies.展开更多
Tumor suppressor p53 is the most frequently mutated gene in human tumors. Meanwhile, under stress conditions, p53 also acts as a transcription factor, regulating the expression of a series of target genes to maintain ...Tumor suppressor p53 is the most frequently mutated gene in human tumors. Meanwhile, under stress conditions, p53 also acts as a transcription factor, regulating the expression of a series of target genes to maintain the integrity of genome. The target genes of p53 can be classified into genes regulating cell cycle arrest, genes involved in apoptosis, and genes inhibiting angiogenesis, p53 protein contains a transactivation domain, a sequence-specific DNA binding domain, a tetramerization domain, a non-specific DNA binding domain that recognizes damaged DNA, and a later identified proline-rich domain. Under stress, p53 proteins accumulate and are activated through two mechanisms. One, involving ataxia telangiectasia-mutated protein （ATM）, is that the interaction between p53 and its down-regulation factor murine double minute 2 （MDM2） decreases, leading to p53 phosphorylation on Serl 5, as determined by the post-translational mechanism; the other holds that p53 increases and is activated through the binding of ribosomal protein L26 （RPL26） or nucleolin to p53 mRNA 5＇ untranslated region （UTR）, regulating p53 translation. Under hypoxia, p53 decreases transactivation and increases transrepression. The mutations outside the DNA binding domain of p53 also contribute to tumor progress, so further studies on p53 should also be focused on this direction. The subter- ranean blind mole rat Spalax in Israel is a good model for hypoxia-adaptation. The p53 of Spalax mutated in residue 172 and residue 207 from arginine to lysine, conferring it the ability to survive hypoxic conditions. This model indicates that p53 acts as a master gene of diversity formation during evolution.展开更多
文摘A coal burst occurred on 15 April, 2014 at the Austar Coal Mine, located west of Newcastle, NSW,Australia. The burst resulted in fatal injuries to two men working as part of the mining crew at the development face. At the time, a continuous miner was being used to mine a longwall development gate road through heavily structured coal, at a depth of approximately 550 m. A number of pre-cursor bumps had occurred on previous shifts, emanating from the coal ribs of the roadway, in proximity to the coal face.This paper reviews the geological, geotechnical and mining conditions and circumstances leading up to the coal burst event; and presents and discusses the available evidence and possible interpretations relating to the geomechanical behaviour mechanisms that may have been critical factors in this incident. The paper also discusses some key technical and operational considerations of ground support systems and mining practices and strategies needed for operating in such conditions in the future.
文摘The aim of this study is to investigate the effect of auditor type and eamings reporting lag on the cost of debt for the Tunisian setting. Our sample consists of 32 Tunisian companies for the period of 2003-2012. Audit quality is measured by auditor size （Big 4 versus non-Big 4） and timely disclosure is proxied by earnings reporting lag. Results show that auditor type is negatively associated with the cost of debt. By contrast, the association between earnings announcement lag and the cost of debt is positive and significant. When testing for the moderating effects of industry and listing status, we document that these associations are more pronounced for industrial companies and listed firms. Finally, the period of investigation slightly moderates the examined associations, since financial institutions become more sensitive to the tardy communication of information and less concerned with auditor type following some economic and political troubles in Tunisia between 2010 and 2012. Our findings have policy implications for managers in the Tunisian setting and other developing economies similar to Tunisia given the crucial role played by debt as an important source of external finance for companies.
基金supported by the National Natural Science Foundation of China (Nos.30393130 and 30870300)the National Basic Research Program (973) of China (No.2006CB504100)
文摘Tumor suppressor p53 is the most frequently mutated gene in human tumors. Meanwhile, under stress conditions, p53 also acts as a transcription factor, regulating the expression of a series of target genes to maintain the integrity of genome. The target genes of p53 can be classified into genes regulating cell cycle arrest, genes involved in apoptosis, and genes inhibiting angiogenesis, p53 protein contains a transactivation domain, a sequence-specific DNA binding domain, a tetramerization domain, a non-specific DNA binding domain that recognizes damaged DNA, and a later identified proline-rich domain. Under stress, p53 proteins accumulate and are activated through two mechanisms. One, involving ataxia telangiectasia-mutated protein （ATM）, is that the interaction between p53 and its down-regulation factor murine double minute 2 （MDM2） decreases, leading to p53 phosphorylation on Serl 5, as determined by the post-translational mechanism; the other holds that p53 increases and is activated through the binding of ribosomal protein L26 （RPL26） or nucleolin to p53 mRNA 5＇ untranslated region （UTR）, regulating p53 translation. Under hypoxia, p53 decreases transactivation and increases transrepression. The mutations outside the DNA binding domain of p53 also contribute to tumor progress, so further studies on p53 should also be focused on this direction. The subter- ranean blind mole rat Spalax in Israel is a good model for hypoxia-adaptation. The p53 of Spalax mutated in residue 172 and residue 207 from arginine to lysine, conferring it the ability to survive hypoxic conditions. This model indicates that p53 acts as a master gene of diversity formation during evolution.
