title: Volatility and skewness spillover between stock index and stock index futures markets during the crash period: New evidence from China

authors: Hou, Yang (Greg)

subjects: Volatility Spillover

abstract: This paper examines volatility and skewness spillover between the Chinese stock index and index futures markets during a market crash in 2015. The volatility spillover from futures to spot is significant and stronger than the other way around. Moreover, the transmission of downside risk is bilateral with the futures market taking the lead. It is revealed that measures announced during the market crash to curb the speculative futures trading enhance the spillover of both volatility and skewness from futures to spot markets. This finding sheds light on validity of such measures to restore market efficiency during a stock market crash.

text: Volatility and skewness spillover between stock index and stock index futures markets during the crash period: New evidence from China This paper examines volatility and skewness spillover between the Chinese stock index and index futures markets during a market crash in 2015. The volatility spillover from futures to spot is significant and stronger than the other way around. Moreover, the transmission of downside risk is bilateral with the futures market taking the lead. It is revealed that measures announced during the market crash to curb the speculative futures trading enhance the spillover of both volatility and skewness from futures to spot markets. This finding sheds light on validity of such measures to restore market efficiency during a stock market crash.

year: 2018

title: Processing of Hemp Fibre Using Enzyme/Fungal Treatment for Composites

authors: Li, Yan

subjects: Fibre

abstract: Hemp fibres compete very well with glass fibres in terms of their specific strength and stiffness and so can replace glass fibres as reinforcement in composites. Combining them with thermoplastics results in potentially cheap recyclable composite materials. The adhesion between the hemp fibre and thermoplastics such as polypropylene is a major factor in the mechanical properties of the composite. Interfacial bonding can be improved by modifications to the fibres, the matrix or both the fibres and the matrix. The aim of this thesis was to investigate low cost and efficient fibre treatment methods with low environmental impact such as bag retting and white rot fungi, and chelator/enzyme treatments which could be applied to hemp fibre in order to create better bonding fibre for potentially recyclable composite materials. 
	
Bag retting was carried out by keeping fresh green hemp fibres in a sealed plastic bag for 1 to 2 weeks to allow natural retting to occur under sealed conditions. For white rot fungi treatments, the dried non-retted hemp fibres were gamma irradiated, and then inoculated with white rot fungi for 2 weeks. Chelator/enzyme treatment was achieved by immersing the fresh green non-retted hemp fibres in solutions consisting of either EDTMP.Na5 (ethylene diamine tetra (methylene phosphonic acid pentasodium salt) or pectinase (P2401) and laccase (53739) for 6 hours.

Several characterization techniques, namely wet chemical analysis, Fourier-transform infrared (FT-IR), scanning electron microscopy (SEM), fibre density testing, X-ray diffraction (XRD), differential thermal analysis (DTA) and thermogravimetric analysis (TGA), zeta potential and single fibre tensile testing were used to assess the effect of treatment on hemp fibres. Wet chemical analysis and FT-IR, were used to measure the chemical compounds present in untreated and treated hemp fibres and showed all treatments removed non-cellulosic compounds from hemp fibre. The separation of untreated and treated fibres was investigated by visual inspection. An examination of surface morphology of hemp fibres carried out using SEM revealed that all treated fibres had cleaner hemp surfaces than untreated ones. The fibre density testing showed that the treated fibre had higher density than untreated fibre. XRD was carried out to assess modification of the crystallinity of fibres and the results showed hemp fibre crystallinity index increased in all treated fibres. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) were used to obtain the activation energies and relative thermal stability of fibres, and indicated that all treatments improved fibre thermal stability. Zeta potential indicated that all treated fibres were more hydrophilic than untreated fibre. Single fibre tensile testing was used to obtain the tensile strength of untreated and treated fibres and it was found that the tensile strength of all treated fibres was reduced.

Short fibre composites were produced by extrusion and injection moulding. Fibres, polypropylene (PP) and a maleated polypropylene (MAPP) coupling agent were compounded using a twin-screw extruder, and then injection moulded into composite tensile test specimens. It was found that all fibre treatments increased the tensile strength of composites. White rot fungi Schizophyllum commune (S.com) treated fibre gave the highest tensile strength of 45 MPa, an increase of 28% compared to composites using untreated fibre. Both the single fibre pull-out test and the Bowyer and Bader model were used to determine the interfacial shear strength (IFSS) of untreated fibre and S.com treated fibre composites. The results obtained from both methods showed that IFSS of the treated fibre composites was higher than that for untreated fibre composites. This supports that the hemp fibre interfacial bonding with PP was improved by white rot fungi treatment. The Bowyer and Bader model was also used to calculate the tensile strength of untreated and S.com treated short fibre composites and results closely match the experimentally values.

text: Processing of Hemp Fibre Using Enzyme/Fungal Treatment for Composites Hemp fibres compete very well with glass fibres in terms of their specific strength and stiffness and so can replace glass fibres as reinforcement in composites. Combining them with thermoplastics results in potentially cheap recyclable composite materials. The adhesion between the hemp fibre and thermoplastics such as polypropylene is a major factor in the mechanical properties of the composite. Interfacial bonding can be improved by modifications to the fibres, the matrix or both the fibres and the matrix. The aim of this thesis was to investigate low cost and efficient fibre treatment methods with low environmental impact such as bag retting and white rot fungi, and chelator/enzyme treatments which could be applied to hemp fibre in order to create better bonding fibre for potentially recyclable composite materials. 
	
Bag retting was carried out by keeping fresh green hemp fibres in a sealed plastic bag for 1 to 2 weeks to allow natural retting to occur under sealed conditions. For white rot fungi treatments, the dried non-retted hemp fibres were gamma irradiated, and then inoculated with white rot fungi for 2 weeks. Chelator/enzyme treatment was achieved by immersing the fresh green non-retted hemp fibres in solutions consisting of either EDTMP.Na5 (ethylene diamine tetra (methylene phosphonic acid pentasodium salt) or pectinase (P2401) and laccase (53739) for 6 hours.

Several characterization techniques, namely wet chemical analysis, Fourier-transform infrared (FT-IR), scanning electron microscopy (SEM), fibre density testing, X-ray diffraction (XRD), differential thermal analysis (DTA) and thermogravimetric analysis (TGA), zeta potential and single fibre tensile testing were used to assess the effect of treatment on hemp fibres. Wet chemical analysis and FT-IR, were used to measure the chemical compounds present in untreated and treated hemp fibres and showed all treatments removed non-cellulosic compounds from hemp fibre. The separation of untreated and treated fibres was investigated by visual inspection. An examination of surface morphology of hemp fibres carried out using SEM revealed that all treated fibres had cleaner hemp surfaces than untreated ones. The fibre density testing showed that the treated fibre had higher density than untreated fibre. XRD was carried out to assess modification of the crystallinity of fibres and the results showed hemp fibre crystallinity index increased in all treated fibres. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) were used to obtain the activation energies and relative thermal stability of fibres, and indicated that all treatments improved fibre thermal stability. Zeta potential indicated that all treated fibres were more hydrophilic than untreated fibre. Single fibre tensile testing was used to obtain the tensile strength of untreated and treated fibres and it was found that the tensile strength of all treated fibres was reduced.

Short fibre composites were produced by extrusion and injection moulding. Fibres, polypropylene (PP) and a maleated polypropylene (MAPP) coupling agent were compounded using a twin-screw extruder, and then injection moulded into composite tensile test specimens. It was found that all fibre treatments increased the tensile strength of composites. White rot fungi Schizophyllum commune (S.com) treated fibre gave the highest tensile strength of 45 MPa, an increase of 28% compared to composites using untreated fibre. Both the single fibre pull-out test and the Bowyer and Bader model were used to determine the interfacial shear strength (IFSS) of untreated fibre and S.com treated fibre composites. The results obtained from both methods showed that IFSS of the treated fibre composites was higher than that for untreated fibre composites. This supports that the hemp fibre interfacial bonding with PP was improved by white rot fungi treatment. The Bowyer and Bader model was also used to calculate the tensile strength of untreated and S.com treated short fibre composites and results closely match the experimentally values.

year: 2009

title: Caregiver Health Related Quality of Life and Burden When Caring for Children with Traumatic Brain Injury

authors: Rose, Wallis

subjects: Caregiver Burden

abstract: Often family members take on the responsibility of caregiver when another family member sustains a traumatic brain injury (TBI). The caregiving role is a stressful task which may impact negatively upon caregivers’ psychological and physical health. Variables which may contribute to caregiver burden include: caregiver age, educational attainment, income, gender, ethnicity, marital status, supports, time post-injury, and child clinical variables: TBI severity, behavioural functioning and adaptive functioning. The literature varies in its reporting of which areas of health are most affected, and the degree to which sociodemographic and child variables impact upon negative health related quality of life (HRQoL) and burden. To address this the current study explored health outcomes for TBI caregivers using a battery of measures (Medical Study Short Form-36, Hospital Anxiety and Depression Scale, DSM-IV Depression Diagnostic Scale, BAKAS Caregiving Outcomes Scale); questionnaires were also used to collect sociodemographic information and information relating to supports and services used in the rehabilitation of the TBI child. The Behavioural Assessment System for Children was used to collect behavioural and adaptability information from the caregivers about the child. Assessments were carried out at baseline, 1-month, 6-months and 12-months post TBI from a sample of 94 TBI caregivers and at baseline from a sample of 43 Control caregivers.

TBI caregivers experienced poorer overall health and higher levels of depression and were less likely to report positive life changes compared to Control caregivers. Older age and higher income predicted positive life changes. In addition to this higher income predicted better physical and overall health. Ethnicity was found to predict depression with the Māori/‘other ethnicity’ group suffering higher levels of depression. Children’s dysfunctional behaviour was found to predict poorer caregiver health outcomes across several domains; these include physical health, overall health, and depression; while the child’s adaptive functioning was not found to be a predictive factor in any caregiver health domains. New Zealand European and Māori TBI caregivers experienced similar health outcomes and received similar levels of support. However, Māori experienced more positive life changes than New Zealand Europeans. Caregivers’ physical and psychological well-being was found to improve over time, these changes were the greatest between the 1-month and 12-month period.
As a high percentage of children’s TBI’s occur in the home and at school, education aimed at schools and parents to inform of the effects of TBI upon children and families will bring an awareness which may encourage families to seek medical help. In doing so will offer the opportunity to receive or seek support in the initial period post TBI in the hope of reducing the burden for caregivers and producing better health outcomes. Bringing these families into contact with medical services may also help in identifying caregivers at higher risk of poorer health outcomes. Findings of more positive life changes for Māori may suggest cultural ideology is a protective factor in caregiver burden, further investigation may be necessary to understand these cultural differences and how they impact upon the caregiving role.

text: Caregiver Health Related Quality of Life and Burden When Caring for Children with Traumatic Brain Injury Often family members take on the responsibility of caregiver when another family member sustains a traumatic brain injury (TBI). The caregiving role is a stressful task which may impact negatively upon caregivers’ psychological and physical health. Variables which may contribute to caregiver burden include: caregiver age, educational attainment, income, gender, ethnicity, marital status, supports, time post-injury, and child clinical variables: TBI severity, behavioural functioning and adaptive functioning. The literature varies in its reporting of which areas of health are most affected, and the degree to which sociodemographic and child variables impact upon negative health related quality of life (HRQoL) and burden. To address this the current study explored health outcomes for TBI caregivers using a battery of measures (Medical Study Short Form-36, Hospital Anxiety and Depression Scale, DSM-IV Depression Diagnostic Scale, BAKAS Caregiving Outcomes Scale); questionnaires were also used to collect sociodemographic information and information relating to supports and services used in the rehabilitation of the TBI child. The Behavioural Assessment System for Children was used to collect behavioural and adaptability information from the caregivers about the child. Assessments were carried out at baseline, 1-month, 6-months and 12-months post TBI from a sample of 94 TBI caregivers and at baseline from a sample of 43 Control caregivers.

TBI caregivers experienced poorer overall health and higher levels of depression and were less likely to report positive life changes compared to Control caregivers. Older age and higher income predicted positive life changes. In addition to this higher income predicted better physical and overall health. Ethnicity was found to predict depression with the Māori/‘other ethnicity’ group suffering higher levels of depression. Children’s dysfunctional behaviour was found to predict poorer caregiver health outcomes across several domains; these include physical health, overall health, and depression; while the child’s adaptive functioning was not found to be a predictive factor in any caregiver health domains. New Zealand European and Māori TBI caregivers experienced similar health outcomes and received similar levels of support. However, Māori experienced more positive life changes than New Zealand Europeans. Caregivers’ physical and psychological well-being was found to improve over time, these changes were the greatest between the 1-month and 12-month period.
As a high percentage of children’s TBI’s occur in the home and at school, education aimed at schools and parents to inform of the effects of TBI upon children and families will bring an awareness which may encourage families to seek medical help. In doing so will offer the opportunity to receive or seek support in the initial period post TBI in the hope of reducing the burden for caregivers and producing better health outcomes. Bringing these families into contact with medical services may also help in identifying caregivers at higher risk of poorer health outcomes. Findings of more positive life changes for Māori may suggest cultural ideology is a protective factor in caregiver burden, further investigation may be necessary to understand these cultural differences and how they impact upon the caregiving role.

year: 2012