bluuebunny/crossref_metadata_2025 huggingface dataset:
Kappa Opioid Receptor (KOR) and GAD67 Immunoreactivity Are Found in off and neutral Cells in the Rostral Ventromedial Medulla
Authors: Winkler Clayton W. , Hermes Sam M. , Chavkin Charles I. , Drake Carrie T. , Morrison Shaun F. , Aicher Sue A.
Published: September 2006

This study combines functional and anatomical characterization of neurons in the rostral ventromedial medulla (RVM) to show distinct neurochemical phenotypes between functional classes of neurons. The RVM contains three functional classes of neurons: off cells show a pause in spontaneous activity prior to a nociceptive withdrawal reflex; on cell activity increases prior to a nociceptive reflex; and neutral cell activity does not change significantly during the nociceptive reflex. We determined if serotonin, glutamate decarboxylase (GAD67), or the kappa opioid receptor (KOR) were differentially located within these cell types as predicted by previous studies. In this study, RVM neurons were recorded extracellularly, functionally characterized, and juxtacellularly labeled with biotinamide. Fixed sections were processed for detection of biotinamide and immunfluorescence either for serotonin or for KOR and GAD67. In the first study, serotonin was found exclusively in a subset of neutral cells (33%). These data substantiate previous findings that serotonin is found in some neutral cells whose role in nociception remains unclear. In the second study, we found KOR immunoreactivity in most off (86%) and neutral (80%) cells but rarely in on (13%) cells. We also found GAD67 immunoreactivity in most off (93%) and neutral cells (80%) but less frequently in on cells (63%). Most KOR-immunoreactive cells (16 of 17) also contained GAD67 immunoreactivity regardless of cell classification. These findings support the hypothesis that KOR agonists directly inhibit off and neutral cell activity. The majority of the off and neutral cells are GABAergic, and some on cells are also GABAergic.
Context-Dependent Modulation of Interlimb Cutaneous Reflexes in Arm Muscles as a Function of Stability Threat During Walking
Authors: Haridas Carlos , Zehr E. Paul , Misiaszek John E.
Published: September 2006

Cutaneous reflexes evoked in the muscles of the arms with electrical stimulation of nerves of the foot (“interlimb reflexes”) are observed during walking. These reflexes have been suggested to coordinate the actions of the legs and arms when walking is disturbed. Recently, we showed that cutaneous reflexes evoked in the leg muscles after stimulation at the foot are modulated according to the level of postural threat during walking. We hypothesized that the amplitude of interlimb cutaneous reflexes would similarly be modulated when subjects walk in unstable environments. Subjects walked on a treadmill under four walking conditions: 1) normal; 2) normal with unpredictable anterior–posterior (AP) perturbations; 3) arms crossed; and 4) arms crossed with unpredictable AP perturbations. Interlimb reflexes evoked from electrical stimulation of the right superficial peroneal or sural nerves were recorded bilaterally, at four points of the step cycle. These reflexes were compared between conditions in which the arms were moving in a similar manner: 1) normal versus AP walking and 2) arms crossed versus arms crossed with AP perturbations. Differences in reflex amplitudes between arms-crossed conditions were observed in most upper limb muscles when subjects were perturbed while walking compared with undisturbed walking. This effect was less apparent when the arms were swinging freely. The results indicate that the strength of interlimb connections is influenced by the level of postural threat (i.e., the context of the behavior), thereby suggesting that these reflexes serve a functional link between the legs and arms during locomotion.
Temporal Dynamics of Figure-Ground Segregation in Human Vision
Authors: Neri Peter , Levi Dennis M.
Published: September 2006

The segregation of figure from ground is arguably one of the most fundamental operations in human vision. Neural signals reflecting this operation appear in cortex as early as 50 ms and as late as 300 ms after presentation of a visual stimulus, but it is not known when these signals are used by the brain to construct the percepts of figure and ground. We used psychophysical reverse correlation to identify the temporal window for figure-ground signals in human perception and found it to lie within the range of 100–160 ms. Figure enhancement within this narrow temporal window was transient rather than sustained as may be expected from measurements in single neurons. These psychophysical results prompt and guide further electrophysiological studies.
Upper and lower bounds for a reactive‐diffuse system with Arrhenius kinetics
Authors: Al-Refai Mohammed , Katatbeh Qutaibeh
Published: September 2006

Comparison arguments are used to study a problem in combustion
theory consisting of a nonlinear parabolic equation together with
initial and boundary conditions. Upper and lower bounds for the
problem are constructed. The lower solutions are used to determine
whether the solution of the problem is increasing in time for
certain initial condition. Numerical results are presented for the
slab, infinite cylinder, and unit sphere. The bounds are compared
with the existing ones in the literature for the slab geometry.
A generalized thermoelastic diffusion problem for an infinitelylong solid cylinder
Authors: Aouadi Moncef
Published: September 2006

The theory of generalized thermoelastic diffusion, based on the
theory of Lord and Shulman, is used to study the
thermoelastic‐diffusion interactions in an infinitely long solid
cylinder subjected to a thermal shock on its surface which is in
contact with a permeating substance. By means of the Laplace
transform and numerical Laplace inversion the problem is solved.
Numerical results predict finite speeds of propagation for
thermoelastic and diffusive waves and the presence of a tensile
stress region close to the cylinder surface. The problem of
generalized thermoelasticity has been reduced as a special case of
our problem.
On a singular integral equation with log kernel and itsapplication
Authors: Banerjea Sudeshna , Sarkar Chiranjib
Published: September 2006

We used function theoretic method to solve a singular integral
equation with logarithmic kernel in two disjoint finite intervals
where the unknown function satisfying the integral equation may be
bounded or unbounded at the nonzero finite endpoints of the
interval concerned. An appropriate solution of this integral
equation is then applied to solve the problem of scattering of
time harmonic surface water waves by a fully submerged thin
vertical barrier with a single gap.
Neighborhoods of certain classes of analytic functions withnegative coefficients
Authors: Aouf M. K.
Published: September 2006

By making use of the familiar concept of neighborhoods of analytic
functions, the author proves several inclusion relations
associated with the (n, δ)‐neighborhoods of various
subclasses defined by Salagean operator. Special cases of
some of these inclusion relations are shown to yield known
results.
Finite symmetric trilinear integral transform of distributions. Part II
Authors: Waghmare G. L. , More S. V.
Published: September 2006

The finite symmetric trilinear integral transform is extended to distributions by using quite different technique than Zemanian (1968) and Dube (1976) and an inversion formula is established using Parseval′s identity. The operational calculus generated is applied to find the temperature inside an equilateral prism of semi‐infinite length.
Perturbed three‐step approximation process with errors for ageneralized implicit nonlinear quasivariational inclusions
Authors: Ahmad M. K. , Salahuddin
Published: September 2006

We initiate and develop some new perturbed three‐step
approximation process with errors for solving generalized
implicit nonlinear quasivariational inclusions. Also, the
convergence and stability of the iterative sequences with errors
generated by the algorithms are presented.
Riesz potential operators and inverses via fractional centredderivatives
Authors: Ortigueira Manuel Duarte
Published: September 2006

Fractional centred differences and derivatives definitions are
proposed, generalizing to real orders the existing ones valid for
even and odd positive integer orders. For each one, suitable
integral formulations are obtained. The computations of the
involved integrals lead to new generalizations of the Cauchy
integral derivative. To compute this integral, a special
two‐straight‐line path was used. With this the referred integrals
lead to the well‐known Riesz potential operators and their
inverses that emerge as true fractional centred derivatives, but
that can be computed through summations similar to the well‐known
Grünwald‐Letnikov derivatives.
On hyper BCC‐algebras
Authors: Borzooei R. A. , Dudek W. A. , Koohestani N.
Published: September 2006

We study hyper BCC‐algebras which are a common generalization of BCC‐algebras and hyper BCK‐algebras. In particular, we investigate different types of hyper BCC‐ideals and describe the relationship among them. Next, we calculate all nonisomorphic 22 hyper BCC‐algebras of order 3 of which only three are not hyper BCK‐algebras.
On empirical Bayes estimation of multivariate regressioncoefficient
Authors: Karunamuni R. J. , Wei L.
Published: September 2006

We investigate the empirical Bayes estimation problem of
multivariate regression coefficients under squared error loss
function. In particular, we consider the regression model
Y = Xβ + ε, where Y is an m‐vector of observations, X is a known m × k matrix, β is an unknown k‐vector, and ε is an m‐vector of unobservable random variables. The problem is squared error loss
estimation of β based on some “previous” data
Y1, …, Yn as well as the “current” data vector Y when β is distributed according to some unknown distribution
G, where Yi satisfies Yi = Xβi + εi, i = 1, …, n. We construct a new empirical Bayes estimator of
β when εi ~ N(0, σ2Im), i = 1, …, n. The performance of the proposed empirical Bayes
estimator is measured using the mean squared error. The rates of
convergence of the mean squared error are obtained.
On the set of distances between two sets over finite fields
Authors: Shparlinski Igor E.
Published: September 2006

We use bounds of exponential sums to derive new lower bounds on the number of distinct distances between all pairs of points (x, y) ∈ ×ℬ for two given sets , where is a finite field of q elements and n ≥ 1 is an integer.
The dynamical U(n) quantum group
Authors: Koelink Erik , Van Norden Yvette
Published: September 2006

We study the dynamical analogue of the matrix algebra M(n), constructed from a dynamical R‐matrix given by Etingof and
Varchenko. A left and a right corepresentation of this algebra,
which can be seen as analogues of the exterior algebra
representation, are defined and this defines dynamical quantum
minor determinants as the matrix elements of these
corepresentations. These elements are studied in more detail,
especially the action of the comultiplication and Laplace
expansions. Using the Laplace expansions we can prove that the
dynamical quantum determinant is almost central, and adjoining an
inverse the antipode can be defined. This results in the dynamical
GL(n) quantum group associated to the dynamical R‐matrix. We
study a ∗‐structure leading to the dynamical U(n) quantum
group, and we obtain results for the canonical pairing arising
from the R‐matrix.
An extension and a refinement of van der Corput′s inequality
Authors: Cao Jian , Niu Da-Wei , Qi Feng
Published: September 2006

van der Corput′s inequality is extended and refined by using
Euler‐Maclaurin formula and other analytic techniques.
Equivalence class in the set of fuzzy numbers and itsapplication in decision‐making problems
Authors: Panda Geetanjali , Panigrahi Motilal , Nanda Sudarsan
Published: September 2006

An equivalence relation is defined in the set of fuzzy numbers. In
a particular equivalence class, arithmetic operations of fuzzy
numbers are introduced. A fuzzy matrix with respect to a
particular class and its associated crisp matrices are also
introduced. The concept of equivalence class is applied in fuzzy
decision‐making problems and justified through a numerical
example.
On weighted inequalities for certain fractional integral operators
Authors: Raina R. K.
Published: September 2006

This paper considers the modified fractional integral operators
involving the Gauss hypergeometric function and obtains
weighted inequalities for these operators. Multidimensional
fractional integral operators involving the H‐function are also
introduced.
Angle distortion theorems for starlike and spirallike functions with respect to a boundary point
Authors: Elin Mark , Shoikhet David
Published: September 2006

We exhibit angle bounds for starlike and spirallike functions with respect to a boundary point. As an application, we obtain a covering theorem for functions convex in one direction.
Timelike trajectories with fixed energy under a potential in static spacetimes
Authors: Germinario Anna
Published: September 2006

By variational methods, we study the motions of a relativistic particle under the action of an external scalar potential. We consider standard static spacetimes whose metric coefficients grow at most quadratically at infinity. Fixing suitable values for the energy, we obtain timelike trajectories.
On weak‐open compact images of metric spaces
Authors: Yin Zhiyun
Published: September 2006

We give some characterizations of weak‐open compact images of metric spaces.
Quantum curve in q‐oscillator model
Authors: Sergeev S.
Published: September 2006

A lattice model of interacting q‐oscillators, proposed by V. Bazhanov and S. Sergeev in 2005 is the
quantum‐mechanical integrable model in 2 + 1 dimensional space‐time. Its layer‐to‐layer transfer matrix is a polynomial of
two spectral parameters, it may be regarded in terms of
quantum groups both as a sum of sl(N) transfer matrices of a
chain of length M and as a sum of sl(M) transfer matrices of
a chain of length N for reducible representations. The aim of
this paper is to derive the Bethe ansatz equations for the
q‐oscillator model entirely in the framework of 2 + 1 integrability providing the evident rank‐size duality.
The truncated exponential polynomials, the associated Hermiteforms and applications
Authors: Dattoli G. , Migliorati M.
Published: September 2006

We discuss the properties of the truncated exponential polynomials and
develop the theory of new form of Hermite polynomials, which can be
constructed using the truncated exponential as a generating function. We
derive their explicit forms and comment on their usefulness in applications,
with particular reference to the theory of flattened beams, used in optics.
Trends in Snowfall versus Rainfall in the Western United States
Authors: Knowles Noah , Dettinger Michael D. , Cayan Daniel R.
Published: September 2006

The water resources of the western United States depend heavily on snowpack to store part of the wintertime precipitation into the drier summer months. A well-documented shift toward earlier runoff in recent decades has been attributed to 1) more precipitation falling as rain instead of snow and 2) earlier snowmelt. The present study addresses the former, documenting a regional trend toward smaller ratios of winter-total snowfall water equivalent (SFE) to winter-total precipitation (P) during the period 1949–2004.

The trends toward reduced SFE are a response to warming across the region, with the most significant reductions occurring where winter wet-day minimum temperatures, averaged over the study period, were warmer than −5°C. Most SFE reductions were associated with winter wet-day temperature increases between 0° and +3°C over the study period. Warmings larger than this occurred mainly at sites where the mean temperatures were cool enough that the precipitation form was less susceptible to warming trends.

The trends toward reduced SFE/P ratios were most pronounced in March regionwide and in January near the West Coast, corresponding to widespread warming in these months. While mean temperatures in March were sufficiently high to allow the warming trend to produce SFE/P declines across the study region, mean January temperatures were cooler, with the result that January SFE/P impacts were restricted to the lower elevations near the West Coast.

Extending the analysis back to 1920 shows that although the trends presented here may be partially attributable to interdecadal climate variability associated with the Pacific decadal oscillation, they also appear to result from still longer-term climate shifts.
ENSO Modulation of the Interannual and Intraseasonal Variability of the East Asian Monsoon—A Model Study
Authors: Lau Ngar-Cheung , Nath Mary Jo
Published: September 2006

The impacts of ENSO on the evolution of the East Asian monsoon have been studied using output from a general circulation model experiment. Observed monthly variations of the sea surface temperature (SST) field have been prescribed in the tropical eastern and central Pacific, whereas the atmosphere has been coupled to an oceanic mixed layer model beyond this forcing region. During the boreal summer of typical El Niño events, a low-level cyclonic anomaly is simulated over the North Pacific in response to enhanced condensational heating over the equatorial central Pacific. Advective processes associated with the cyclone anomaly lead to temperature tendencies that set the stage for the abrupt establishment of a strong Philippine Sea anticyclone (PSAC) anomaly in the autumn. The synoptic development during the onset of the PSAC anomaly is similar to that accompanying cold-air surges over East Asia.

The air–sea interactions accompanying the intraseasonal variations (ISV) in the model atmosphere exhibit a strong seasonal dependence. During the summer, the climatological monsoon trough over the subtropical western Pacific facilitates positive feedbacks between the atmospheric and oceanic fluctuations. Conversely, the prevalent northeasterly monsoon over this region in the winter leads to negative feedbacks. The onset of the PSAC anomaly is seen to be coincident with a prominent episode of the leading ISV mode. The ENSO events could influence the amplitude of the ISV by modulating the large-scale flow environment in which the ISV are embedded. Amplification of the summer monsoon trough over the western Pacific during El Niño enhances air–sea feedbacks on intraseasonal time scales, thereby raising the amplitudes of the ISV. A weakening of the northeasterly monsoon in El Niño winters suppresses the frequency and strength of the cold-air surges associated with the leading ISV mode in that season.

Many aspects of the model simulation of the relationships between ENSO and the East Asian monsoon are in agreement with observational findings.
On the Connection between Dense Water Formation, Overturning, and Poleward Heat Transport in a Convective Basin*
Authors: Straneo Fiammetta
Published: September 2006

An isopycnal, two-layer, idealized model for a convective basin is proposed, consisting of a convecting, interior region and a surrounding boundary current (buoyancy and wind-driven). Parameterized eddy fluxes govern the exchange between the two. To balance the interior buoyancy loss, the boundary current becomes denser as it flows around the basin. Geostrophy imposes that this densification be accompanied by sinking in the boundary current and hence by an overturning circulation. The poleward heat transport, associated with convection in the basin, can thus be viewed as a result of both an overturning and a horizontal circulation. When adapted to the Labrador Sea, the model is able to reproduce the bulk features of the mean state, the seasonal cycle, and even the shutdown of convection from 1969 to 1972. According to the model, only 40% of the poleward heat (buoyancy) transport of the Labrador Sea is associated with the overturning circulation. An exact solution is presented for the linearized equations when changes in the boundary current are small. Numerical solutions are calculated for variations in the amount of convection and for changes in the remotely forced circulation around the basin. These results highlight how the overturning circulation is not simply related to the amount of dense water formed. A speeding up of the circulation around the basin due to wind forcing, for example, will decrease the intensity of the overturning circulation while the dense water formation remains unvaried. In general, it is shown that the fraction of poleward buoyancy (or heat) transport carried by the overturning circulation is not an intrinsic property of the basin but can vary as a result of a number of factors.
Estimates and Implications of Surface Eddy Diffusivity in the Southern Ocean Derived from Tracer Transport
Authors: Marshall John , Shuckburgh Emily , Jones Helen , Hill Chris
Published: September 2006

Near-surface “effective diffusivities” associated with geostrophic eddies in the Southern Ocean are estimated by numerically monitoring the lengthening of idealized tracer contours as they are strained by surface geostrophic flow observed by satellite altimetry. The resulting surface diffusivities show considerable spatial variability and are large (2000 m2 s−1) on the equatorward flank of the Antarctic Circumpolar Current and are small (500 m2 s−1) at the jet axis. Regions of high and low effective diffusivity are shown to be collocated with regions of, respectively, weak and strong isentropic potential vorticity gradients. The maps of diffusivity are used, along with climatological estimates of surface wind stress and air–sea buoyancy flux, to estimate surface meridional residual flows and the relative importance of Eulerian and eddy-induced circulation in the streamwise-averaged dynamics of the Antarctic Circumpolar Current.
Forms of government and spending on common municipal functions: a longitudinal approach
Authors: Jung Changhoon
Published: September 2006

This study analyses whether reformed cities (council-manager form) spend less than unreformed cities (mayor-council and commission forms) by examining per capita spending on common municipal functions of a panel of 504 American cities with populations over 50,000 during 1980-2000. Unlike most previous studies, the study employs a fixed effects model of the pooled cross-sectional time-series research design to better capture changing effects of municipal structure on spending level. Findings in the study indicate that per capita spending on common municipal functions in reformed cities is not statistically different from unreformed cities. However, when the two narrowest common municipal functions (police and fire) are examined, spending in council-manager cities is significantly less than in the non-council-manager cities for the police function, but not significant for the fire function. The findings suggest further detailed studies should be conducted considering population size, functional scope (responsibilities), forms of municipal government (e.g. newly emerging hybrid structure cities), region, metro status, and other variables for a better understanding of the effects of municipal structure on the level of spending. Furthermore, a more elaborated conceptual approach should be developed to better capture the factors affecting municipal spending level.
The difficult match between a territorial policy instrument and the industry-centred tradition of French agricultural policies: the Land Management Contract (LMC)
Authors: Léger François , Vollet Dominique , Urbano Ghislaine
Published: September 2006

Between 1999 and 2002, the Land Management Contract (LMC) programme was the principal mechanism implemented by France in response to the demands of the European Rural Development Regulation. It was presented as a territorial policy instrument, at the service of sustainable development that set out to encourage the multifunctionality of agriculture. However, the mid-term evaluation of the programme revealed that its conditions of implementation did not make it possible to fully achieve these ambitions. While it may have helped to make the principle of the contractualization of subsidies more generally accepted and legitimized the notion of the environment as a criterion in the definition of agricultural policies, more often than not, the definition frameworks of these contracts were restricted to the agricultural sphere alone and their target public to the relatively limited fringe group of farmers who were already familiar with the workings of the departmental institutions in charge of agricultural development. This paper sets out to not only describe some of the limitations of this programme but also its positive repercussions. Both are important factors if we want to approach national and European agricultural policy in terms of territorialization and with due consideration for rural development issues. The LMC was the main instrument of the Agriculture Framework Law of 1999 that embodied a ‘new approach to the management of public action’ via a policy that ‘takes into account the economic, environmental and social functions of agriculture and participates in land management with a view to sustainable development’, as stipulated by the first article of the Agriculture Framework Law of 9 July 1999.
Trajectories of institutional design in policy networks: European interventions in the Dutch fishery network as an example
Authors: van Buuren Arwin , Klijn Erik-Hans
Published: September 2006

This article focuses on the strategies and processes of institutional design. It starts by recognizing that politicians often try to change institutional structures of networks and therefore more theoretical and empirical attention for these strategies is needed. First, the article provides a brief theoretical framework for understanding institutional changes and identifying institutional design strategies. Then it illustrates the framework by in-depth empirical research of the institutional changes in the Dutch fishery network as a result of the interventions of the European Union. The article first elaborates the strategic interventions of the EU and then traces the changes of rules as constructed and reconstructed by the actors in the network. The article ends by assessing the influence of the EU interventions and also by presenting some reflections on the concept of institutional design.
Public management training economic analysis: a real options approach
Authors: Pennisi Giuseppe
Published: September 2006

This article explores the application of cost-benefit analysis extended to real options (ECBA) to the area of management training and more specifically of public management training. Although methodological, the presentation is in non-mathematical form and in a language generally accessible to managers and administrators. After an introductory section on the main features of ECBA, it deals with its relevance to management training as well as with the most relevant ‘call’ and ‘put’ options normally faced in the design of public management training. It reviews the potential of ECBA in a selected number of recent training analyses and charts a research agenda which could parallel or complement that being implemented by various agencies, e.g. by the Italian Advanced School of Public Administration (Scuola Superiore della Pubblica Amministrazione, SSPA), a number of Dutch universities, the World Bank—in infrastructure and other sectors.
Flesh-hooks, technological complexity and the Atlantic Bronze Age feasting complex
Authors: Needham Stuart , Bowman Sheridan
Published: September 2006

Thirty-six Atlantic flesh-hooks are documented, classified and discussed after critical evaluation of previously identified examples and the addition of new ones. A chronological progression is shown from the more simple classes to the more complex from 1300 to 800 cal BC, but even the latter examples begin as early as c.1100 cal BC. Although highly distinctive, the Atlantic series derives ultimately from similar hooked instruments to the east and newly recognized Sicilian examples introduce an alternative path of dissemination from the more usually accepted intermediary route of the Urnfield culture. The rarity of flesh-hooks is striking and understanding of their social role needs to take into account not only their marked individuality in terms of technological construction or iconographic features, but also their relationship to other contemporary prestige feasting gear. The distributions of flesh-hooks and rotary spits are mutually exclusive over most of Atlantic Europe; thus, not only did they function differently at a practical level, but also at an ideological one. On the other hand, flesh-hooks and cauldrons have very similar distributions but they have a paucity of direct associations. Rather than implying a limited functional relationship, this is interpreted as resulting from their different symbolic meanings and thus different depositional practices. The zoomorphic imagery encountered on Atlantic spits and occasionally on flesh-hooks is found to be unique to each instrument and thus seen to contrast with that of the Urnfield world, suggesting the signalling of tribal or clan identity rather than an over-arching symbolism.
Transformational Classroom Leadership
Authors: Pounder James S.
Published: September 2006

The literature on teacher leadership suggests that the notion has developed over time and some have argued that this development comprises three stages or ‘waves’ that progressively delink the idea from the formal organizational hierarchy. The third wave emphasizes that teacher leadership is a process rather than a positional concept and notes that teacher leaders tend to possess many of the characteristics of transformational leaders. The literature also suggests that third wave teacher leaders are excellent classroom performers. This article explores the relationship between the teacher leadership and transformational leadership concepts and argues that a fourth wave of teacher leadership could include transformational classroom leadership as one of the defining qualities of a teacher leader and could embrace both school and university contexts.
Workable Compromise or Pointless Exercise?
Authors: McNamara Gerry , O’Hara Joe
Published: September 2006

Evaluating schools has become a contentious issue in many countries. There seems to be a broad and growing consensus that some form of evaluation can on the one hand play a significant role in school improvement efforts, and on the other is also required to provide a reasonable level of public accountability appropriate in democratic societies. What is less clear is how the balance between these goals can be best achieved. In the context of this wider international debate, the article describes the manner in which the approach to the evaluation of the work of schools is evolving in the Irish setting. In so doing, it is hoped to contribute to some key elements of the debate, particularly the interplay between external evaluation and internal self-evaluation and the relationship between evaluation and evidence.
Observations of the experiences of people with dementia on general hospital wards
Authors: Norman Rachel
Published: September 2006

This paper is based on research that aimed to explore how people with dementia are cared for in general hospital wards in the United Kingdom (UK). The paper details findings from one phase of data collection, ward based observations. The observations elucidated the ways in which persons with dementia express and portray their ‘selves’, the interpretations made by nurses about the patients with dementia they cared for and the constructions of roles and care environments. The findings demonstrate how a variety of influences affect the way a person with dementia experiences a hospital admission. Nurses' positive or negative interpretations of a person with dementia can lead to the ‘constraint’ or ‘realisation’ of a person's portrayal of self. In an ageing global society, improving the care of older people is a priority. The findings illuminate the central importance of promoting two-way relationships in which the actions of people with dementia are recognised as portraying individuality and identity. The study highlights a need for practice development to enhance nursing care for medical and surgical patients with a coincidental diagnosis of dementia.
Living renal donation
Authors: Crombie Alison K.
Published: September 2006

‘Saving life’ has become a dominant rhetoric of twentieth-century science-based medicine. One key process through which this is most visible is that associated with the rapidly increasing technologies of transplantation. From the very beginning of transplantation techniques, the possible advantages of ‘live donation’ have been espoused. Such donation has been considered to have a number of advantages. These have related to function — being a better match, for example, and also in many cases to availability. In a further development of this approach, familial living donation in relation to kidney failure has sometimes been seen as ‘the answer’ to organ shortages.

This paper describes the use of ethnography in a busy teaching hospital amongst renal clinicians. The methodology has enabled the author to capture the social and cultural context of living donation. The paper highlights how individual medical-value orientations juxtapose rational, technological ways of knowing with interpretative, intuitive and experiential knowledge.
Ethnographic evidence
Authors: Savage Jan
Published: September 2006

The move towards evidence-based healthcare across the industrialised world has raised questions about the nature of evidence, and how good evidence is determined. In response to a hierarchy of evidence in which findings from qualitative research are deemed to be the lowest form, qualitative researchers have underscored the different agendas of qualitative and quantitative research, and the potential for qualitative inquiry to explore complex problems, including the experiential components of healthcare. This paper, which provides a context for the other papers on ethnography in this journal issue, looks at ethnography in the context of this debate. It first offers an overview of what is meant by ethnography, its different forms of practice, and how it relates to qualitative research more broadly. It then looks at how ethnography has been applied in organisational and healthcare settings, before considering the nature of evidence that qualitative inquiry, and particularly ethnographic inquiry, can provide. It argues that, within the qualitative paradigm, ethnography is particularly valuable because of the attention it gives to context and its synthesis of findings from different methods. Moreover, ethnography offers a holistic way of exploring the relationship between the different kinds of evidence that underpin clinical practice.
Using participant observation to immerse oneself in the field
Authors: Allan Helen T.
Published: September 2006

In this paper I draw on the findings of an ethnographic study of fertility nursing in a British fertility unit to explore the relevance and importance of ethnography for illuminating the role of emotions in nursing practice. One of the main findings to emerge from the original study was that infertility was an emotional experience for both staff and patients, and that the organisation of the unit ensured that the potentially disruptive emotions of staff and patients were controlled and remained private. These findings have been reported elsewhere (Allan, 2001, 2002). Drawing on these findings, I discuss the role of ethnography in illuminating the role of emotions in the clinic in two ways. First, I will discuss the nature of the data in ethnography and the relationship between participant observation and interviews. Second, I will discuss the experience of researcher reflexivity and ethnographic authority in ethnography.
X-ray microtomographic observation of intergranular stress corrosion cracking in sensitised austenitic stainless steel
Authors: Babout L. , Marrow T. J. , Engelberg D. , Withers P. J.
Published: September 2006

Intergranular stress corrosion cracking in a sensitised type 302 stainless steel wire has been observed in situ using high resolution X-ray microtomography. Tomography enables the development and failure of crack bridging ligaments to be studied in detail in three dimensions. Direct comparison of these features has been made with scanning electron microscopy fractography. The crack bridges failed in a ductile manner, with a morphology that is consistent with non-sensitised low energy grain boundaries.
Three-dimensional visualisation of fatigue cracks in metals using high resolution synchrotron X-ray micro-tomography
Authors: Buffiere J. Y. , Ferrie E. , Proudhon H. , Ludwig W.
Published: September 2006

The present paper reviews recent developments in high resolution synchrotron X-ray micro-tomography for the study of fatigue cracks in metals. The possibilities and limitations of the tomography technique are described. A fatigue machine used for in situ cycling of samples is presented and three-dimensional images of the growth of fatigue cracks initiated in various Al alloys on natural or artificial defects are shown. Examples of quantitative use of such 3D images are given.
MicroCT (microtomography) quantification of microstructure related to macroscopic behaviour: Part 1 – Fatigue crack closure measured in situ in AA 2090 compact tension samples
Authors: Ignatiev K. I. , Davis G. R. , Elliott J. C. , Stock S. R.
Published: September 2006

Microcomputed tomography (microCT) quantified crack opening in situ in a small compact tension specimen (AA 2090 T8E41) as a function of 3D position and of applied load. The same specimen was observed twice at two crack lengths. Some crack face areas were dominated by large asperities, while others were relatively flat. Large openings followed the sides of large asperities, with small openings elsewhere. The crack path and pattern of openings are discussed in terms of the variation in mesotexture. Before and after the crack extension, the pattern of open (and closed) voxels did not appear to change, suggesting that contact at a point near the crack tip will continue at the same portion of the fatigue cycle after the tip has receded. Testing parameters and macroscopic closure measurements link the present microCT measurements to studies in the literature.
MicroCT (microtomography) quantification of microstructure related to macroscopic behaviour: Part 2 – Damage in SiC–Al monofilament composites tested in monotonic tension and fatigue
Authors: Breunig T. M. , Kinney J. H. , Stock S. R.
Published: September 2006

The present paper reports results of monotonic tensile and of fatigue testing of an aligned monofilament composite SiC–Al. Macroscopic measures of damage (changes in unloading compliance and in unrecovered strain) correlate with noninvasive X-ray microCT (microtomography) quantification of microstructure (alteration of fibre separation, fibre misorientation relative to the load axis and amount of fibre fracture). Monotonic loading beyond yield (188 MPa) alters fibre arrangement and reduces fibre misorientation. Fracture of fibre carbon cores begins at 828 MPa and increases rapidly with rising stress concomitant with marked unloading modulus decreases and permanent strain increases. Fatigue at 621 MPa produces gradually increasing modulus and unrecovered strain with no evidence of fibre damage. At low cycles, the modulus, permanent strain and fraction of fractured C cores increase while fibre misorientation decreases; above 16 cycles, modulus decreases with gradual increases in the other quantities. Fracture in SiC could only be observed after the specimen broke.
Visualising complex morphology of fatigue cracks in voxel based 3D datasets
Authors: Müller B. , Pfrunder F. , Chiocca L. , Ruse N. Dorin , Beckmann F.
Published: September 2006

Fatigue cracks are usually characterised by surface sensitive techniques after specimen failure. High resolution micro computed tomography (μCT) based on synchrotron radiation allows the non-destructive visualisation of crack morphology and evaluation of fatigue crack formation/propagation before specimen failure. The visualisation of the complex fracture morphology with characteristic features out of the acquired set of slices is, however, challenging. To obtain a reasonable estimate, two approaches are generally used: the determination of mass centre points in the hollow space and the minimum intensity search in parallel projections. The more sophisticated approach using the elastically deformable contour model, the physical analogy of a rubber band, termed snakes, gives rise to crack morphologies with much less artefacts. The approach was used in the present study for the characterisation of fatigue cracks in poly(methylmethacrylate) (PMMA) and a dental ceramic. The search for the appropriate snake parameters works much better for homogeneous materials, here PMMA, than for inhomogeneous materials, here a dental ceramic. For the ceramic, the regions where the snakes approach provided reasonable results were restricted. Combining μCT with sophisticated computer vision techniques enables the unique characterisation of cracks at the micrometre scale.
X-ray microtomographic characterisation of pore evolution during homogenisation and rolling of Al–6Mg
Authors: Youssef Y. M. , Chaijaruwanich A. , Hamilton R. W. , Nagaumi H. , Dashwood R. J. , Lee P. D.
Published: September 2006

The effect of homogenisation heat treatment and subsequent hot rolling on the evolution of porosity in a direct chill cast Al–6Mg (wt-%) alloy was studied. Porosity was quantified using conventional 2D optical metallography and X-ray microtomography (XMT) which allowed 3D imaging. Metallographic observations show an increase in maximum pore length during heat treatment and at the centre line during rolling. These observations together with the high temperatures might suggest a classical interpore Ostwald ripening mechanism is operative. However, XMT revealed that the pores have a highly tortuous shape, which when sectioned metallographically is not apparent and can lead to misinterpretation. X-ray microtomography observations proved that these tortuous 3D shapes spheroidised during homogenisation owing to localised coarsening of high curvatures within the complex, branching structure of each pore, termed intrapore coarsening. Accelerated centreline intrapore coarsening was observed during the initial rolling passes when relatively low reduction ratios were used. Finite element modelling was used to demonstrate that under the geometric rolling conditions employed the central region of the billet experienced a tensile rather than a compressive hydrostatic stress. This combined with deformation enhanced diffusion is proposed as the reason for the accelerated intrapore spheroidisation. X-ray microtomography was critical to revealing the true 3D pore shape and the mechanisms of pore coarsening, which could have been misinterpreted if only 2D metallography was used.
Plane strain compression of high silicon steel
Authors: Calvillo P. R. , Ros-Yanez T. , Ruiz D. , Colás R. , Houbaert Y.
Published: September 2006

A series of plane strain compression tests were conducted at room temperature on a high silicon steel to study the behaviour of this material owing to the similarity of this test with rolling. The tests were performed in a specially designed machine able to control the strain rate profile and the amount of deformation. The material was cast and hot rolled to a thickness of 4 mm from which the experimental samples were machined. Plane strain compression tests were carried out at three constant rates of strain (0·01, 0·1 and 1 s−1) up to four levels of equivalent strain (0·15, 0·30, 0·45 and 0·60). 57Fe Mössbauer spectroscopy analyses indicate that the degree of order of the material decreases with the amount of deformation until a strain of 0·45 is achieved; a further increase in strain augments the order of the material. It is found that the strain rate sensitivity close to yielding is negative, but converts to positive once a stain of ∼0·04 is surpassed. Microstructural analyses of deformed samples show that deformation is by twinning and shear. Electron backscattered diffraction analyses indicate that twinning occurs only at an early stage of deformation within grains with {111} planes parallel to the plane of deformation. Deformation twinning takes place in all grains at later stages of deformation.
Ion nitrided AISI H13 tool steel Part I – Microstructural aspects
Authors: Cruz M. R. , Nachez L. , Gomez B. J. , Nosei L. , Feugeas J. N. , Staia M. H.
Published: September 2006

In the present paper, five different operating conditions of a plasma nitriding process on annealed AISI H13 were investigated. A systematic variation of processing parameters such as gas mixture, time of processing and current density has been carried out in order to study their effect on microstructure. X-ray diffraction, microhardness testing and scanning electron microscopy techniques coupled with semiquantitative energy dispersive X-ray analysis were used to characterise the nitrided samples. The results revealed that the current density during plasma processing has a considerable influence on both the compound layer formation and depth of the diffusion zone. Also, it has been shown that the geometrical configuration of the workload may affect the uniformity of the diffusion zone, giving rise to the presence of heterogeneous nitrogen distribution zones along it.
On microstructure, hardness and wear behaviour of flame sprayed Co base alloy coating deposited on mild steel
Authors: Yadav A. K. , Arora N. , Dwivedi D. K.
Published: September 2006

In the present paper, the influence of preheat and post-spray heat treatment temperature on microstructure and adhesive wear behaviour of flame sprayed Co base hard facing alloy (EWAC 1006 EE) coatings on mild steel has been reported. Coatings were deposited by oxyacetylene thermal spraying torch. Thermal spraying of substrate was carried out at two preheat temperatures, i.e. 300 and 350°C. The post-spray heat treatment of the coatings was carried out at three different temperatures: 650, 750 and 850°C, for 2 h. Wear resistance of coatings was evaluated using ring on block wear system at 40 N normal load and 1 m s−1 sliding speed of ring. Hardness of coating, base metal and interface was tested using Vickers hardness testing machine. Optical studies of the microstructure of the substrate, interface and coating were carried out to investigate the influence of preheat and post-spray heat treatment temperatures. It has been found that an increase in post-spray heat treatment temperature enhances the hardness and wear resistance of the coating.