title: Comparison of the telegraph and hyperdiffusion approximations in cosmic-ray transport

authors: Litvinenko, Yuri E.

abstract: The telegraph equation and its generalizations have been repeatedly considered in the models of diffusive cosmic-ray transport. Yet the telegraph model has well-known limitations, and analytical arguments suggest that a hyperdiffusion model should serve as a more accurate alternative to the telegraph model, especially on the timescale of a few scattering times. We present a detailed side-by-side comparison of an evolving particle density profile, predicted by the telegraph and hyperdiffusion models in the context of a simple but physically meaningful initial-value problem, compare the predictions with the solution based on the Fokker–Planck equation, and discuss the applicability of the telegraph and hyperdiffusion approximations to the description of strongly anisotropic particle distributions.

text: Comparison of the telegraph and hyperdiffusion approximations in cosmic-ray transport The telegraph equation and its generalizations have been repeatedly considered in the models of diffusive cosmic-ray transport. Yet the telegraph model has well-known limitations, and analytical arguments suggest that a hyperdiffusion model should serve as a more accurate alternative to the telegraph model, especially on the timescale of a few scattering times. We present a detailed side-by-side comparison of an evolving particle density profile, predicted by the telegraph and hyperdiffusion models in the context of a simple but physically meaningful initial-value problem, compare the predictions with the solution based on the Fokker–Planck equation, and discuss the applicability of the telegraph and hyperdiffusion approximations to the description of strongly anisotropic particle distributions.

year: 2016

title: Policies, programs, and practices: Exploring the complex dynamics of assessment education in teacher education across four countries

authors: DeLuca, Christopher

subjects: assessment literacy

abstract: There has been a global trend toward increased accountability and assessment in schools over the past several decades. Across policy and professional standards, teachers have been repeatedly called to integrate assessment throughout their practice to identify, monitor, support, evaluate, and report on student learning. This professional capacity to integrate and utilize assessment to effectively facilitate student learning has long been characterized as teachers' “assessment literacy,” or more recently “assessment competency,” and “assessment capability”. Concerningly, research indicates that teachers generally maintain low levels of assessment knowledge and skills, with beginning teachers particularly underprepared for assessment in schools. This persistent finding is unsurprising as researchers argue that assessment has historically been a neglected area of study in teacher education programs. However, with the rise of accountability mandates, assessment is beginning to occupy a more prominent and necessary role in pre-service preparatory programs. However, analyzing and situating assessment education in relation to broader conceptions of assessment literacy remains necessary in order to effectively promote the assessment capability of beginning teachers. Likewise, understanding how assessment education and assessment literacy are shaped by the complex dynamics and larger teacher education frameworks and how they contribute to teachers' developing professional identities is essential in constructing a more comprehensive view of teacher preparation within and for accountability-driven systems of education. This paper analyzes teacher education policies, programs, and practices aimed at supporting initial teacher learning in assessment across four country contexts: Australia, Canada, England, and New Zealand. Bernstein's (1999) codes of classification and framing provide an analytic discourse for examining the vertical and horizontal messages about assessment that shape teacher capability in this key area of professional practice. In drawing on policy and teacher education documents and qualitative data (i.e., interview and teacher reflections) from across each country context, the paper concludes with five consistent and interconnected findings about the complex landscape for teacher preparation in assessment.

text: Policies, programs, and practices: Exploring the complex dynamics of assessment education in teacher education across four countries There has been a global trend toward increased accountability and assessment in schools over the past several decades. Across policy and professional standards, teachers have been repeatedly called to integrate assessment throughout their practice to identify, monitor, support, evaluate, and report on student learning. This professional capacity to integrate and utilize assessment to effectively facilitate student learning has long been characterized as teachers' “assessment literacy,” or more recently “assessment competency,” and “assessment capability”. Concerningly, research indicates that teachers generally maintain low levels of assessment knowledge and skills, with beginning teachers particularly underprepared for assessment in schools. This persistent finding is unsurprising as researchers argue that assessment has historically been a neglected area of study in teacher education programs. However, with the rise of accountability mandates, assessment is beginning to occupy a more prominent and necessary role in pre-service preparatory programs. However, analyzing and situating assessment education in relation to broader conceptions of assessment literacy remains necessary in order to effectively promote the assessment capability of beginning teachers. Likewise, understanding how assessment education and assessment literacy are shaped by the complex dynamics and larger teacher education frameworks and how they contribute to teachers' developing professional identities is essential in constructing a more comprehensive view of teacher preparation within and for accountability-driven systems of education. This paper analyzes teacher education policies, programs, and practices aimed at supporting initial teacher learning in assessment across four country contexts: Australia, Canada, England, and New Zealand. Bernstein's (1999) codes of classification and framing provide an analytic discourse for examining the vertical and horizontal messages about assessment that shape teacher capability in this key area of professional practice. In drawing on policy and teacher education documents and qualitative data (i.e., interview and teacher reflections) from across each country context, the paper concludes with five consistent and interconnected findings about the complex landscape for teacher preparation in assessment.

year: 2019

title: The source, composition and typology of ‘Limestone’ Adzes from Eastern North Island, New Zealand

authors: Nelson, Campbell S.

subjects: adzes

abstract: Collections of stone adzes (toki) from the eastern North Island of New Zealand include a number of typologically early (Archaic) forms made from what has been previously described as ‘siliceous or silicified limestone’. Seventy five finished adzes and preforms of this material were recorded in the present study. Their geographic distribution is primarily restricted to southern Hawkes Bay – Wairarapa, and they apparently originated from a single manufacturing centre at Owahanga, on the northern Wairarapa coast. Chemical and mineralogical analyses (by X-ray fluorescence, portable XRF, vacuum gasometry and X-ray diffraction) of two artefacts from Owahanga show they contain about 20–30 per cent CaCO3 (as calcite), while samples of the presumed local source rock have a slightly higher carbonate content but comparable silica (quartz) and Rb concentrations. The rock type used in the manufacture of adzes was therefore not a true limestone but calcareous mudstone, compositionally distinct from siliceous limestones in southern Wairarapa and probably derived from the Whangai Formation. Possible reasons for the use of this stone material are discussed.

text: The source, composition and typology of ‘Limestone’ Adzes from Eastern North Island, New Zealand Collections of stone adzes (toki) from the eastern North Island of New Zealand include a number of typologically early (Archaic) forms made from what has been previously described as ‘siliceous or silicified limestone’. Seventy five finished adzes and preforms of this material were recorded in the present study. Their geographic distribution is primarily restricted to southern Hawkes Bay – Wairarapa, and they apparently originated from a single manufacturing centre at Owahanga, on the northern Wairarapa coast. Chemical and mineralogical analyses (by X-ray fluorescence, portable XRF, vacuum gasometry and X-ray diffraction) of two artefacts from Owahanga show they contain about 20–30 per cent CaCO3 (as calcite), while samples of the presumed local source rock have a slightly higher carbonate content but comparable silica (quartz) and Rb concentrations. The rock type used in the manufacture of adzes was therefore not a true limestone but calcareous mudstone, compositionally distinct from siliceous limestones in southern Wairarapa and probably derived from the Whangai Formation. Possible reasons for the use of this stone material are discussed.

year: 2016