title: The activity of family 11 xylanases at alkaline pH

authors: Gibbs, M.D.

subjects: xylanases

abstract: Xylanases have several industrial uses, particularly in baking, modification of animal feed and in pulp bleaching in the paper industry. Process conditions in kraft pulp bleaching generally favour an enzyme that is active at high pH values. The activities of several glycosyl hydrolase family 11 xylanases reported to be active under alkaline conditions were determined under optimal conditions and found to have optima in the pH 5–6 range. Only one enzyme tested, BadX, was shown to have an alkaline pH optimum. Significant activity at pH values higher than 8 appears often to be the result of excess enzyme added to the reaction mixtures so that substrate is limiting. The different nature of laboratory and industrial substrates needs to be taken into consideration in designing assay conditions. In some cases, significant differences were observed in pH profiles generated using a small-molecule substrate when compared to those generated using xylan. We conclude that small-molecule substrates are not a suitable proxy for determining the pH profiles of family 11 xylanases.

text: The activity of family 11 xylanases at alkaline pH Xylanases have several industrial uses, particularly in baking, modification of animal feed and in pulp bleaching in the paper industry. Process conditions in kraft pulp bleaching generally favour an enzyme that is active at high pH values. The activities of several glycosyl hydrolase family 11 xylanases reported to be active under alkaline conditions were determined under optimal conditions and found to have optima in the pH 5–6 range. Only one enzyme tested, BadX, was shown to have an alkaline pH optimum. Significant activity at pH values higher than 8 appears often to be the result of excess enzyme added to the reaction mixtures so that substrate is limiting. The different nature of laboratory and industrial substrates needs to be taken into consideration in designing assay conditions. In some cases, significant differences were observed in pH profiles generated using a small-molecule substrate when compared to those generated using xylan. We conclude that small-molecule substrates are not a suitable proxy for determining the pH profiles of family 11 xylanases.

year: 2010

title: The parallel diffusion coefficient and adiabatic focusing of cosmic-ray particles

authors: Litvinenko, Yuri E.

subjects: cosmic rays

abstract: In this paper, the problem of focused particle transport is revisited. A description in terms of a system of stochastic differential equations, completely equivalent to the Fokker-Planck equation, is suggested. The coefficient for spatial diffusion parallel to the mean magnetic field is calculated. The case of isotropic pitch angle scattering and weak focusing is analyzed in detail. The disagreement between a recent analysis by Shalchi and other treatments of the same problem is discussed.

text: The parallel diffusion coefficient and adiabatic focusing of cosmic-ray particles In this paper, the problem of focused particle transport is revisited. A description in terms of a system of stochastic differential equations, completely equivalent to the Fokker-Planck equation, is suggested. The coefficient for spatial diffusion parallel to the mean magnetic field is calculated. The case of isotropic pitch angle scattering and weak focusing is analyzed in detail. The disagreement between a recent analysis by Shalchi and other treatments of the same problem is discussed.

year: 2012

title: The spatial equity and sustainability of general practitioner services: A mixed methods analysis of the Waikato DHB region

authors: Whitehead, Jesse

subjects: spatial equity

abstract: The New Zealand Primary Health Care Strategy states that quality primary health care is the first level of contact with the health system and should be universally accessible. Effective primary health care is an essential component of health systems, and is associated with more equitable distributions of health outcomes. However, not all New Zealanders have ready access to primary health care. For instance, adult residents of the Waikato region, and in particular Māori, have higher levels of unmet need for primay care than others. Improving the spatial equity of health services is a key step in achieving health equity. Health systems should contribute to achieving health equity and maintaining sustainable and equitable services into the future. 

This thesis research examines the spatial equity and sustainability of general practitioner (GP) services in the Waikato DHB region, using a mixed-methods approach to identify not only where inequities exist, but why they occur. A conceptual framework establishes a foundation for examining spatial equity and sustainability in New Zealand. Next, a systematic literature review identifies common definitions and measures of spatial equity. Primary Health Organisation (PHO) enrolment data is used to examine patterns of patient enrolment at GP services, and a range of health needs indicators were assessed for their suitability in the New Zealand primary care context. These findings inform the development of a Geographic Information Systems (GIS) model of spatial accessibility that is tailored to the Waikato District Health Board (DHB) context. The GIS model is then used, in combination with in-depth qualitative interviews, to examine the spatial equity and sustainability of GP services in the Waikato DHB region. 

Key findings include that spatial equity is commonly defined as a ‘need-based distribution of resources’, which can be quantified using a range of statistical and geospatial measures and techniques. PHO enrolment analysis revealed that most patients do not enrol with their closest service, and that the size of the ‘catchment area’ served by GP clinics varies with rurality. Analysis of indicators of health need suggest that ‘Ambulatory Sensitive Hospitalisations’ are a robust indicator; however, area-level socioeconomic deprivation is also strongly associated with other indicators of need and data is more widely available to researchers. Mixed-methods analysis suggests that GP services are not distributed equitably within the Waikato DHB region and that key barriers to access include the affordability, appropriateness, and availability of services. New Zealand’s history of colonisation and discrimination are identified as fundamental drivers of health inequity. Furthermore, population growth and ageing suggest that current levels of access to GP services are unlikely to be maintained in the future, while participants identify key economic, professional, organisation, and social dimensions that influence service sustainability in New Zealand.

text: The spatial equity and sustainability of general practitioner services: A mixed methods analysis of the Waikato DHB region The New Zealand Primary Health Care Strategy states that quality primary health care is the first level of contact with the health system and should be universally accessible. Effective primary health care is an essential component of health systems, and is associated with more equitable distributions of health outcomes. However, not all New Zealanders have ready access to primary health care. For instance, adult residents of the Waikato region, and in particular Māori, have higher levels of unmet need for primay care than others. Improving the spatial equity of health services is a key step in achieving health equity. Health systems should contribute to achieving health equity and maintaining sustainable and equitable services into the future. 

This thesis research examines the spatial equity and sustainability of general practitioner (GP) services in the Waikato DHB region, using a mixed-methods approach to identify not only where inequities exist, but why they occur. A conceptual framework establishes a foundation for examining spatial equity and sustainability in New Zealand. Next, a systematic literature review identifies common definitions and measures of spatial equity. Primary Health Organisation (PHO) enrolment data is used to examine patterns of patient enrolment at GP services, and a range of health needs indicators were assessed for their suitability in the New Zealand primary care context. These findings inform the development of a Geographic Information Systems (GIS) model of spatial accessibility that is tailored to the Waikato District Health Board (DHB) context. The GIS model is then used, in combination with in-depth qualitative interviews, to examine the spatial equity and sustainability of GP services in the Waikato DHB region. 

Key findings include that spatial equity is commonly defined as a ‘need-based distribution of resources’, which can be quantified using a range of statistical and geospatial measures and techniques. PHO enrolment analysis revealed that most patients do not enrol with their closest service, and that the size of the ‘catchment area’ served by GP clinics varies with rurality. Analysis of indicators of health need suggest that ‘Ambulatory Sensitive Hospitalisations’ are a robust indicator; however, area-level socioeconomic deprivation is also strongly associated with other indicators of need and data is more widely available to researchers. Mixed-methods analysis suggests that GP services are not distributed equitably within the Waikato DHB region and that key barriers to access include the affordability, appropriateness, and availability of services. New Zealand’s history of colonisation and discrimination are identified as fundamental drivers of health inequity. Furthermore, population growth and ageing suggest that current levels of access to GP services are unlikely to be maintained in the future, while participants identify key economic, professional, organisation, and social dimensions that influence service sustainability in New Zealand.

year: 2020