bluuebunny/crossref_metadata_2025 huggingface dataset:
Probabilistic assessment of “dangerous” climate change and emissions pathways
Authors: Schneider Stephen H. , Mastrandrea Michael D.
Published: September 2005

Climate policy decisions driving future greenhouse gas mitigation efforts will strongly influence the success of compliance with Article 2 of the United Nations Framework Convention on Climate Change, the prevention of “dangerous anthropogenic interference (DAI) with the climate system.” However, success will be measured in very different ways by different stakeholders, suggesting a spectrum of possible definitions for DAI. The likelihood of avoiding a given threshold for DAI depends in part on uncertainty in the climate system, notably, the range of uncertainty in climate sensitivity. We combine a set of probabilistic global average temperature metrics for DAI with probability distributions of future climate change produced from a combination of several published climate sensitivity distributions and a range of proposed concentration stabilization profiles differing in both stabilization level and approach trajectory, including overshoot profiles. These analyses present a “likelihood framework” to differentiate future emissions pathways with regard to their potential for preventing DAI. Our analysis of overshoot profiles in comparison with non-overshoot profiles demonstrates that overshoot of a given stabilization target can significantly increase the likelihood of exceeding “dangerous” climate impact thresholds, even though equilibrium warming in our model is identical for non-overshoot concentration stabilization profiles having the same target.
Blue light-regulated molecular switch of Ser/Thr kinase in phototropin
Authors: Matsuoka Daisuke , Tokutomi Satoru
Published: September 2005

Phototropin is a blue light photoreceptor for tropic responses, relocation of chloroplasts, and stomata opening in plants. Phototropin has two chromophoric domains named light-oxygen-voltage-sensing (LOV) 1 and 2 in the N-terminal half, and a serine/threonine (Ser/Thr) protein kinase motif in the C-terminal half. Concerning the kinase activity of phototropin, only autophosphorylation has been detected so far. However, we found that phototropin can phosphorylate a protein other than phototropin itself. Bacterially expressed
Arabidopsis
phototropin 2 kinase domain (KD) with GST-tag showed a constitutive kinase activity on casein, a common
in vitro
substrate of Ser/Thr protein kinase. By using this
in vitro
assay system, the roles of each LOV domain were studied. Addition of LOV2 to KD (GST-L2-KD) inhibits the kinase activity that is canceled by light. This light activation of kinase disappeared on introduction of a mutation blocking photochemical reaction in the LOV2 domain. Accordingly, LOV2 domain acts as a major light-regulated molecular switch of casein phosphorylation. Interestingly, isolated LOV2 from the KD still binds to the KD in a light-dependent manner and functions in similar ways, indicating the role of LOV2 domain as an inhibitor of the kinase activity in the substrate phosphorylation. LOV1, in contrast, contributes little to the photoactivation in GST-L1-L2-KD; however, it acts as an attenuator of the light activation of the kinase by LOV2.
Bicoid cooperative DNA binding is critical for embryonic patterning in
Drosophila
Authors: Lebrecht Danielle , Foehr Marisa , Smith Eric , Lopes Francisco J. P. , Vanario-Alonso Carlos E. , Reinitz John , Burz David S. , Hanes Steven D.
Published: September 2005

Cooperative interactions by DNA-binding proteins have been implicated in cell-fate decisions in a variety of organisms. To date, however, there are few examples in which the importance of such interactions has been explicitly tested
in vivo
. Here, we tested the importance of cooperative DNA binding by the Bicoid protein in establishing a pattern along the anterior–posterior axis of the early
Drosophila
embryo. We found that
bicoid
mutants specifically defective in cooperative DNA binding fail to direct proper development of the head and thorax, leading to embryonic lethality. The mutants did not faithfully stimulate transcription of downstream target genes such as
hunchback
(
hb
),
giant
, and
Krüppel
. Quantitative analysis of gene expression
in vivo
indicated that
bcd
cooperativity mutants were unable to accurately direct the extent to which
hb
is expressed along the anterior–posterior axis and displayed a reduced ability to generate sharp on/off transitions for
hb
gene expression. These failures in precise transcriptional control demonstrate the importance of cooperative DNA binding for embryonic patterning
in vivo
.
Nonpharmacological amelioration of age-related learning deficits: The impact of hippocampal θ-triggered training
Authors: Asaka Yukiko , Mauldin Kristin N. , Griffin Amy L. , Seager Matthew A. , Shurell Elizabeth , Berry Stephen D.
Published: September 2005

Age-related learning deficits are often attributed to deterioration of hippocampal function. Conversely, a well studied index of hippocampal activity, the θ rhythm, is known to enhance hippocampal plasticity and accelerate learning rate in young subjects, suggesting that manipulations of θ activity might be used as a means to counteract impairments related to the aging process. Here, young and older rabbits were given eyeblink conditioning trials either when exhibiting hippocampal θ (θ+) or regardless of hippocampal activity (yoked control). Although, as expected, older-yoked control animals showed a learning deficit, the older θ+ group learned as fast as young controls, demonstrating that aging deficits, at least in eyeblink classical conditioning, can be overcome by giving trials during episodes of hippocampal θ activity. The use of several learning criteria showed that the benefits of hippocampal θ occur in multiple phases of learning that may depend on different cognitive or motor processes. Whereas there was a benefit of θ-triggered training in both age groups during the early phase of acquisition, the enhancement persisted in older animals, peaking during later performance. These findings have implications for theories of age-related memory deficits and may contribute to the development of beneficial treatments.
Sustainable Urban Livelihoods and Marketplace Social Capital: Crisis and Strategy in Petty Trade
Authors: Lyons Michal , Snoxell Simon
Published: September 2005

Urban growth has been accompanied by the development of bimodal labour markets and increasing inequalities in both North and South. In Southern cities, many of the poor have turned to the informal sector, in particular to street trade. This has resulted in a multiplicity of urban conflicts and has led to pressure on urban managers to undertake formalisation, for which an increasingly developmental approach has been advocated. Nevertheless, for traders, the formalisation of street trade has very uneven outcomes. The starting-point for this article is the premise that not enough is known about the social fabric upon which trading careers depend. Adopting sustainable livelihoods as a conceptual framework and drawing on social capital theory, four questions are addressed. How do trading careers survive over time? Are there differences in the survival strategies for which social capital is employed among traders operating in different political, cultural and socioeconomic contexts? In the new processes of urbanisation, are the old relationships on which social capital is based, simply lost in the new, or are traditional networks and structures adapted? Finally, what policy conclusions should be drawn to inform urban management practices as they relate to trade formalisation? The primary findings are that marketplace social capital is increasingly important to traders' economic capital. However, inherited ties, although they diminish in importance, continue to be valuable and often serve as the basis for the development of contingent ties. Implications are discussed for urban management and planning practice, for planning theory and for social capital theory.
What Drives Infrastructure Spending in Cities of Developing Countries?
Authors: Arimah Ben C.
Published: September 2005

There exists a dearth of empirical studies on what determines infrastructure spending in cities of developing countries. This in part can be attributed to the absence of quality data and the tendency for researchers to gloss over variations in infrastructure expenditure in or across developing world cities in the general belief that investment in infrastructure is generally low. Using the United Nations Human Settlements Programme's global urban indicators database, this paper examines variations in infrastructure spending across cities in developing countries with a view to identifying the factors that explain these differences. The empirical analysis identifies substantial intercity variations in infrastructure spending both across and within the regions of Africa, Asia, the Middle East, Latin America and the Caribbean, and the economies in transition. Further analysis suggests that intercity variations in infrastructure spending are accounted for by differences in the macroeconomic environment, urban growth rate, quality of governance and financial capacity of municipal governments.
A Transitional Institution for the Emerging Land Market in Urban China
Authors: Zhu Jieming
Published: September 2005

Chinese economic reforms since 1978 have been a continuous process of fundamental institutional change. The new institution of ambiguous property rights over state-owned urban land evolves from the socialist people's landownership. This institutional change is driven by the changing economic system and by two new organisations-the local developmental state and danwei-enterprises. The new institution facilitates the formation of an emerging land market. This land market, structured by ambiguous property rights, has accounted for the dynamic urban physical growth in many of China's coastal cities in the 1980s and 1990s. Nevertheless, massive rent dissipation induced by the new institution does not provide market certainty, nor does it offer incentives for optimal development. The cost incurred by the institution is gradually overtaking its benefit. The ambiguous property rights are deemed to be a transitional institution during the development of land markets in urban China.
In Search of the City in Spatial Strategies: Past Legacies, Future Imaginings
Authors: Vigar Geoff , Graham Stephen , Healey Patsy
Published: September 2005

This paper addresses the ways in which urban regions are represented in contemporary urban policies. In doing so, it critically examines how urban trends are reflected in diverse notions of 'cityness' in contemporary policy discourses about spatiality and territoriality. Through a detailed case study of the use and construction of the word 'city' in a range of urban governance contexts in Newcastle upon Tyne, this paper analyses the political work done by diverse representations and invocations of 'cityness' in contemporary urban governance. Such representations matter because the way in which contemporary cities are conceptualised influences policy formulations and policy outcomes. In addition, considerable emphasis is being placed in contemporary urban policy on 'joining-up', 'integrating' and co-ordinating governance efforts. How conceptions of the city are mobilised to do such integrating work provides insight into the challenge such ambitions present. The evidence from the case study suggests that the capacity of local actors to think about the processes of change in metropolitan regions, and to define the ways in which they can respond, is often limited, as they struggle to define what their 'city' actually might be these days. This tends to be to the detriment of collective attempts to maximise conditions for citizens and for investment.
Cities and National Economic Growth: A Reappraisal
Authors: Polèse Mario
Published: September 2005

The idea that cities are sources of economic growth, generally associated with Jane Jacobs, has gained ground in the scholarly literature in recent years. This essay proposes a review of the arguments for and against the Jacobs hypothesis. Much of the debate centres on the existence of dynamic agglomeration economies. It is difficult, it is argued to rigorously test the relationship between agglomeration and economic growth. Part of the problem stems from the difficulty of distinguishing factors that allow cities to capture a greater share of national economic growth from those that allow cities to add to national economic growth. It is argued that the socioeconomic processes that explain economic growth operate primarily at the national/societal level and not at the city level.
Head Office Location: Agglomeration, Clusters or Flow Nodes?
Authors: Jakobsen Stig-Erik , Onsager Knut
Published: September 2005

How can we understand head office location in a knowledge-intensive urban economy? This is the basic question addressed in this paper. Even if proximity is important in understanding location, a study must also emphasise the multiplicity of connections that surpass the cluster or city level, which are critical for the operation of the head office. The study offers new insights into the categorisation of head office location and illustrates the importance of a multilevel perspective by analysing head offices as nodes within a system of internal, regional and external flows of knowledge and information. This theoretical approach is inspired by the work of Amin and Thrift. The paper's theory-informed discussion is based on empirical data from a survey of the largest companies in Norway and on intensive case studies from a selection of these firms.
Growth in Commuting Distances in French Polycentric Metropolitan Areas: Paris, Lyon and Marseille
Authors: Aguilera Anne
Published: September 2005

It has frequently been suggested in the literature that a polycentric distribution of employment and people shortens commuting distances because people locate within or close to their employment sub-centre (the co-location hypothesis). Having studied the three biggest French metropolitan areas over the past decade it has been established that co-location affects only a minority of inhabitants, of whom there are fewer in 1999 than there were nine years earlier. Indeed, the majority of people living in a sub-centre work outside their sub-centre of residence. This situation was even more marked in 1999 than it was in 1990. In addition to this, the majority of jobs located in sub-centres are held by non-residents who are generally living further and further from their place of work.
The Intention to Move and Residential Location Choice Behaviour
Authors: Kim Jae Hong , Pagliara Francesca , Preston John
Published: September 2005

This paper aims to quantify the extent to which transport and other factors impact on residential decisions using Oxfordshire, UK, as a case study. It investigates the impacts of the current dwelling, household characteristics and alternative properties on the probability of moving. It also highlights the trade-off between access, space and other attributes in residential location choice. Particular emphasis is placed on assessing the impact of transport and location-embedded amenities. A nested logit model is applied to estimate the indirect random utility functions of the intention to move and residential location choice based on stated preference data. The estimation results of the intentions to move model illustrate the impact of housing and household characteristics on the probability of moving. The estimation results of the residential location choice model quantify the trade-offs between transport, amenities and other factors.
Assessing the Geography of Vandalism: Evidence from a Swedish City
Authors: Ceccato Vania , Haining Robert
Published: September 2005

This paper investigates the occurrence of vandalism at the small-area level for the Swedish city of Malmo using data from the Skane Police Authority's database. Demographic, socioeconomic and land use characteristics measured at the small-area level are used as predictors of vandalism with particular interest in the role of collective resources. Standardised vandalism ratios were calculated and mapped using a geographical information system (GIS). Spatial regression models were used to test hypotheses relating to the variation in vandalism rates. Findings show that spatial variation in vandalism is significantly related to social disorganisation risk factors as well as land use factors, but that the physical presence of local leisure associations (a 'collective resource') produces higher vandalism rates.
Criticisms of educational research: key topics and levels of analysis
Authors: Oancea Alis
Published: September 2005

The article is an exploration of the meanings and worthiness of criticism as a significant phenomenon in the evolution of educational research during the 1990s. While drawing on an overview of the vast amount of documents expressing criticisms of educational research in the UK, western and eastern continental Europe and the USA, it summarises the findings of a study based on the analysis of some of the most influential texts that criticised educational research in the UK during the mid‐1990s: Hargreaves (1996), Tooley and Darby (1998), Hillage et al. (1998). An understanding of the targets, sources, solutions and actors that are characteristic of the recent criticisms of educational research is proposed, together with an exploration of the rhetorical devices employed in expressing criticism and of some of the philosophical themes that underpin the recent debates.
Explanation and quantification in educational research: the arguments of critical and scientific realism
Authors: Nash Roy
Published: September 2005

The influence of Bhaskar's critical realism has become increasingly evident in the debate on the nature of educational research. This philosophy, dedicated to the overthrow of positivist doctrines, in particular those of empiricism, nominalism, and causation as constant conjunction, is the foundation of contemporary proposals for new perspectives and possibilities in educational research. There are, however, aspects of critical realism, as it is presented, that may repay further reflection. This article suggests that the rejection of statistical modelling by critical realism is not supported by scientific realism. The argument is illustrated by substantive analyses of the relationship between poverty and educational attainment (reading) using the PISA (Programme for International Student Assessment) 2000 UK data set. It is concluded that an approach to the construction of explanatory narratives based on scientific realism is more likely to effect a principled integration of the theory and practice of qualitative and quantitative research.
Making a difference: an exploration of leadership roles within sixth form colleges in maintaining ethos within a context of change
Authors: Briggs Ann R. J.
Published: September 2005

In 2001–02, the Nuffield Foundation funded research into the impact of government policy upon the management of sixth form colleges since 1992. National and regional questionnaire surveys were carried out among senior managers at sixth form colleges, further education colleges and schools. Case studies were undertaken at five sixth form colleges in the North‐West and South‐East of England, and in the East Midlands. This article reports on the findings in relation to the following factors: the prevailing ethos of sixth form colleges, the changing context within which that ethos is maintained, and the role of leaders at all levels of the colleges in maintaining it.
Are secondary schools spending enough on books?
Authors: Hurd Steve , Mangan Jean , Adnett Nick
Published: September 2005

Evidence is provided to illustrate that the current level of spending on books by English secondary schools is low with regard to maintaining existing book stocks and that parental expenditure is not making up the shortfall. An analysis of the inspection regime suggests a tendency to emphasise information and communications technology (ICT) to the relative neglect of books. The authors also provide an empirical study at school level of the respective contribution of books, ICT and other inputs to both student performance and overall success in inspections. Its findings raise important questions about not only the efficiency of resource allocation but also the role and mutual consistency of the examination and inspection systems.
Generalized Cellular Hypertrophy is Induced by a Dual-Acting PPAR Agonist in Rat Urinary Bladder Urothelium In Vivo
Authors: Oleksiewicz Martin B. , Thorup Inger , Nielsen Henriette S. , Andersen Hanne V. , Hegelund Anne Charlotte , Iversen Lars , Guldberg Torben S. , Brinck Peter R. , Sjogren Ingrid , Thinggaard Ulla K. , Jørgensen Lis , Jensen Marianne B.
Published: September 2005

Some developmental dual-acting PPARα/γ agonists, such as ragaglitazar, have shown carcinogenic effects in the rodent urinary bladder urothelium after months-years of dosing. We examined early (precancerous) changes in the bladder urothelium of rats orally dosed with ragaglitazar, using a newly developed flow cytometric method. Following 3 weeks of oral ragaglitazar dosing, increases in physical size occurred in a generalized fashion in rat bladder urothelial cells, determined by flow cytometry. Protein/DNA measurements confirmed increased protein content of urothelial cells in the bladder, and hypertrophy was observed in the kidney pelvis urothelium by histopathology. In animals exhibiting urothelial hypertrophy, no cell cycle changes were detected in parallel samples of bladder urothelium. Interestingly, urothelial cells from normal rats were found to constitute a unique type of noncycling population, with high G2/M fractions. In summary, our findings showed that in the urothelium of ragaglitazar-treated animals, hypertrophy (increased size and protein content per cell) was an early change, that affected the whole bladder urothelial cell population. The urothelial hypertrophy was primary, i.e., occurred in the absence of similarly pronounced changes in cell cycle distributions. To our knowledge, this is the first report of a direct hypertrophic effect of a PPAR agonist. Urothelial hypertrophy might be a relevant early biological endpoint in mechanistic studies regarding the bladder-carcinogenic effect of PPAR agonists.
Restructuring the Automotive Industry in the English West Midlands
Authors: Donnelly Tom , Barnes Sally , Morris David
Published: September 2005

This paper investigates the changes taking places in the automotive industry in the English West Midlands. For over a century this region has been the heartland of car production in the UK, but over recent decades the volume side of the trade has been in serious decline, leading to increasing dependence on the luxury side of the industry. The implications are that the supply side of the industry will be forced to move into new technologies if the auto cluster is to prosper in future. Finally, the paper looks at the attempts made by bodies such as Advantage West Midlands and the industry itself to effect change.
Delivering Quality Accommodation for Small Businesses in London despite Market Difficulties
Authors: Large Martin , Rushton Chris
Published: September 2005

Public policy on the subject of small business support generally concentrates on tackling market failures in delivering finance, innovation, technical development, skills and entrepreneurship. However, in growing city regions such as London, the difficulty in obtaining good quality fit-for-purpose accommodation can be an important factor inhibiting the growth of otherwise successful business. The rate of business formation is very high in London, but paradoxically, the very vibrancy of the economy creates a real estate market that can be hostile to the needs of small businesses, particularly those which achieve rapid growth. This article will consider the factors that cause this situation and will then outline some practical examples of how they can be overcome by smart public sector intervention.
A Mini-Review of fMRI Studies of Human Medial Temporal Lobe Activity Associated with Recognition Memory
Authors: Henson Richard
Published: September 2005

This review considers event-related functional magnetic resonance imaging (fMRI) studies of human recognition memory that have or have not reported activations within the medial temporal lobes (MTL). For comparisons both between items at study (encoding) and between items at test (recognition), MTL activations are characterized as left/right, anterior/posterior, and hippocampus/surrounding cortex, and as a function of the stimulus material and relevance of item/source information. Though no clear pattern emerges, there are trends suggesting differences between item and source information, and verbal and spatial information, and a role for encoding processes during recognition tests. Important future directions are considered.
Contrasting Hippocampal and Perirhinalcortex Function using Immediate Early Gene Imaging
Authors: Aggleton John P. , Brown Malcolm W.
Published: September 2005

The perirhinal cortex and hippocampus have close anatomical links, and it might, therefore, be predicted that they have close, interlinked roles in memory. Lesion studies have, however, often failed to support this prediction, providing dissociations and double dissociations between the two regions on tests of object recognition and spatial memory. In a series of rat studies we have compared these two regions using the expression of the immediate early gene c- fosas a marker of neuronal activity. This gene imaging approach makes it possible to assess the relative involve-ment of different brain regions and avoids many of the limitations of the lesion approach. A very consistent pattern of results was found as the various hippocampal subfields but not the peri-rhinal cortex show increased c- fosactivity following tests of spatial learning. In contrast, the perirhinal cortex but none of the hippocampal subfields show increased c- fosactivity when presented with novel rather than familiar visual objects. When novel scenes are created by the spatial rearrangement of familiar objects it is the hippocampus and not the perirhinal cortex that shows c- foschanges. This double dissociation for gene expression accords with that found from lesion studies and highlights the different contributions of the perirhinal cortex and hippocampus to memory.
The Role of the Perirhinal Cortex and Hippocampus in Learning, Memory, and Perception
Authors: Buckley Mark J.
Published: September 2005

One traditional and long-held view of medial temporal lobe (MTL) function is that it contains a system of structures that are exclusively involved in memory, and that the extent of memory loss following MTL damage is simply related to the amount of MTL damage sustained. Indeed, human patients with extensive MTL damage are typically profoundly amnesic whereas patients with less extensive brain lesions centred upon the hippocampus typically exhibit only moderately severe anterograde amnesia. Accordingly, the latter observations have elevated the hippocampus to a particularly prominent position within the purported MTL memory system. This article reviews recent lesion studies in macaque monkeys in which the behavioural effects of more highly circumscribed lesions (than those observed to occur in human patients with MTL lesions) to different subregions of the MTL have been examined. These studies have reported new findings that contradict this concept of a MTL memory system. First, the MTL is not exclusively involved in mnemonic processes; some MTL structures, most notably the perirhinal cortex, also contribute to perception. Second, there are some forms of memory, including recognition memory, that are not always affected by selective hippocampal lesions. Third, the data support the idea that regional functional specializations exist within the MTL. For example, the macaque perirhinal cortex appears to be specialized for processing object identity whereas the hippocampus may be specialized for processing spatial and temporal relationships.
Monkey Perirhinal Cortex is Critical for Visual Memory, but not for Visual Perception: Reexamination of the Behavioural Evidence from Monkeys
Authors: Hampton Robert R.
Published: September 2005

Overdependence on discrimination learning paradigms to assess the function of perirhinal cortex has complicated understanding of the cognitive role of this structure. Impairments in discrimination learning can result from at least two distinct causes: (a) failure to accurately apprehend and represent the relevant stimuli, or (b) failure to form and remember associations between stimulus representations and reward. Thus, the results of discrimination learning experiments do not readily differentiate deficits in perception from deficits in learning and memory. Here I describe studies that do dissociate learning and memory from perception and show that perirhinal cortex damage impairs learning and/or memory, but not perception. Reanalysis and reconsideration of other published data call into further question the hypothesis that the monkey perirhinal cortex plays a critical role in visual perception.
The Roles of Perirhinal Cortex, Postrhinal Cortex, and the Fornix in Memory for Objects, Contexts, and Events in the Rat
Authors: Eacott M. J. , Gaffan E. A.
Published: September 2005

Investigation of the anatomical substructure of the medial temporal lobe has revealed a number of highly interconnected areas, which has led some to propose that the region operates as a unitary memory system. However, here we outline the results of a number of studies from our laboratories, which investigate the contributions of the rat's perirhinal cortex and postrhinal cortex to memory, concentrating particularly on their respective roles in memory for objects. By contrasting patterns of impairment and spared abilities on a number of related tasks, we suggest that perirhinal cortex and postrhinal cortex make distinctive contributions to learning and memory: for example, that postrhinal cortex is important in learning about within-scene position and context. We also provide evidence that despite the strong connectivity between these cortical regions and the hippocampus, the hippocampus, as evidenced by lesions of the fornix, has a distinct function of its own—combining information about objects, positions, and contexts.
The Perceptual-Mnemonic/Feature Conjunction Model of Perirhinal Cortex Function
Authors: Bussey Timothy J. , Saksida Lisa M. , Murray Elisabeth A.
Published: September 2005

The perirhinal cortex was once thought to be “silent cortex”, virtually ignored by researchers interested in the neurobiology of learning and memory. Following studies of brain damage associated with cases of amnesia, perirhinal cortex is now widely regarded as part of a “medial temporal lobe (MTL) memory system”. This system is thought to be more or less functionally homogeneous, having a special role in declarative memory, and making little or no contribution to other functions such as perception. In the present article, we summarize an alternative view. First, we propose that components of the putative MTL system such as the hippocampus and perirhinal cortex have distinct and dissociable functions. Second, we provide evidence that the perirhinal cortex has a role in visual discrimination. In addition, we propose a specific role for perirhinal cortex in visual discrimination: the contribution of complex conjunctive representations to the solution of visual discrimination problems with a high degree of “feature ambiguity”. These proposals constitute a new view of perirhinal cortex function, one that does not assume strict modularity of function in the occipito-temporal visual stream, but replaces this idea with the notion of a hierarchical representational continuum.
Reduction of absorbed dose in storage phosphor urography by significant lowering of tube voltage and adjustment of image display parameters
Authors: Wiltz H. J. , Petersen U. , Axelsson B.
Published: September 2005

Purpose: To investigate whether image quality in storage phosphor urography can be maintained when the X‐ray tube voltage is significantly lowered to give a lower patient dose.

Material and Methods: Initial phantom studies were used to establish exposure settings at 53 kV that gave signal‐to‐noise ratios for contrast media structures equivalent to those obtained at the reference kilovoltage of 69 kV. Dose area product and image quality, assessed by image quality criteria and visual grading, were then recorded for 44 patients drawn at random to be examined by either the standard or modified technique.

Results: Absorbed dose could be reduced by more than 30% without any significant change in image quality in manually controlled exposures and by 13% in exposures controlled by AEC.

Conclusion: It might be possible to lower the tube voltage in digital examinations involving contrast media as a means of lowering patient dose. The image display parameters need to be adjusted to maintain image quality.
Diffusion‐weighted and conventional magnetic resonance imaging in cerebral cryptococcoma
Authors: Ho T.‐L. , Lee H.‐J. , Lee K.‐W. , Chen W.‐L.
Published: September 2005

A case of cryptococcoma involving the right cerebral hemisphere is reported. The diffusion‐weighted image shows hypointensity in the central cavity of the cryptococcoma, while apparent diffusion coefficient maps show hyperintensity. The imaging features of an intracerebral cryptococcoma mimic that of a central necrotic brain tumor, rather than a pyogenic brain abscess.
Staging N0 oral cancer: lymphoscintigraphy and conventional imaging
Authors: Thomsen J. B. , Sørensen J. A. , Grupe P. , Karstoft J. , Krogdahl A.
Published: September 2005

Purpose: To compare sentinel lymph node biopsy, magnetic resonance imaging (MRI), Doppler ultrasonography, and palpation as staging tools in patients with T1/T2 N0 cancer of the oral cavity.

Material and Methods: Forty consecutive patients were enrolled (17 F and 23 M, aged 32–90 years), 24 T1 and 16 T2 cN0 squamous cell carcinoma of the oral cavity. Palpation was carried out by two observers prior to inclusion. MRI, gray-scale and Doppler ultrasonography were performed. Lymphoscintigraphies were done after peritumoral injections of 99mTc labelled rheniumsulphide nanocolloid, followed by sentinel lymph node biopsy guided by a gamma probe and Patent Blue. Palpation, Doppler ultrasonography, MRI, and sentinel lymph node biopsy were compared to a combination of histopathology and follow-up. Diagnostic testing was performed using the x2 test.

Results: Histopathological examination revealed metastatic spread to the neck in 14 of 40 patients. One patient had bilateral neck disease. Sentinel lymph node biopsy and ultrasonography were performed in 80 neck sides of 40 patients and MRI in 70 neck sides (5 patients were claustrophobic). SN revealed suspicious lymph nodes in 12 necks, ultrasonography in 23 necks, and MRI in 9 necks. The positive predictive value of sentinel lymph node biopsy was 100%, ultrasonography 57%, and MRI 56%. The respective negative predictive values were 96%, 96%, and 85%. The sensitivity of sentinel lymph node biopsy 80% was comparable to ultrasonography 87%, but the sensitivity of MRI 36% was low. The specificities were 100%, 85%, and 93%, respectively. By combined sentinel lymph node biopsy and ultrasonography the overall sensitivity could have been 100%.

Conclusion: Sentinel lymph node biopsy improved staging of patients with small N0 oral cancers. Combined sentinel lymph node biopsy and Doppler ultrasonography may further improve staging. MRI and simple palpation results were poor.
Multiple hemangiomas involving the vertebral column
Authors: Sainani N. I. , Pungavkar S. A. , Patkar D. P. , Lawande M. A. , Naik M.
Published: September 2005

Hemangiomas are benign, slow-growing skeletal and soft tissue tumors that commonly involve the bony spine. When found in the spine, they are usually asymptomatic, but can sometimes be associated with local pain and/or neurological deficits. We report the case of a middle-aged Indian male with multiple hemangiomas involving almost all the vertebrae contiguously from C2 to S1 vertebral levels. These were discovered incidentally when a magnetic resonance scan was performed for backache. To the best of our knowledge, such extensive involvement of the spine has not been reported previously.
Standardized volume-rendering of contrast-enhanced renal magnetic resonance angiography
Authors: Smedby Ö. , Öberg R. , Åsberg B. , Stenström H. , Eriksson P.
Published: September 2005

Purpose: To propose a technique for standardizing volume-rendering technique (VRT) protocols and to compare this with maximum intensity projection (MIP) in regard to image quality and diagnostic confidence in stenosis diagnosis with magnetic resonance angiography (MRA).

Material and Methods: Twenty patients were examined with MRA under suspicion of renal artery stenosis. Using the histogram function in the volume-rendering software, the 95th and 99th percentiles of the 3D data set were identified and used to define the VRT transfer function. Two radiologists assessed the stenosis pathology and image quality from rotational sequences of MIP and VRT images.

Results: Good overall agreement (mean κ = 0.72) was found between MIP and VRT diagnoses. The agreement between MIP and VRT was considerably better than that between observers (mean κ = 0.43). One of the observers judged VRT images as having higher image quality than MIP images.

Conclusion: Presenting renal MRA images with VRT gave results in good agreement with MIP. With VRT protocols defined from the histogram of the image, the lack of an absolute gray scale in MRI need not be a major problem.
Extensive cerebrospinal fluid enhancement following gadolinium chelate administration: possible pathogenesis
Authors: Hsu H.-L. , Chen C.-J.
Published: September 2005

Diffuse cerebrospinal fluid (CSF) enhancement following gadolinium administration is a rarely recognized phenomenon, and its mechanism is not fully understood. We report two cases of diffuse CSF enhancement following gadolinium administration and review the literature. We conclude that the contributing factors of this phenomenon include blood-CSF barrier disruption, increased dosage, impair renal clearance, delayed imaging after contrast administration, and use of different pulse sequences.
Cerebral fat embolism: diffusion-weighted magnetic resonance imaging findings
Authors: Ryu C. W. , Lee D. H. , Kim T. K. , Kim S. J. , Kim H. S. , Lee J. H. , Choi C. G. , Suh D. C.
Published: September 2005

Purpose: To demonstrate the diffusion-weighted (DWI) magnetic resonance imaging (MRI) findings, and the follow-up MRI findings, of cerebral fat embolism in the acute stage.

Material and Methods: The initial DWI and clinical findings of six patients with cerebral fat embolism were retrospectively evaluated. The finding of DWI with a b-value of 1000 s/mm2(b = 1000) was compared with that of DWI with a b-value of 0 s/mm2(b = 0). In three patients who underwent follow-up MRI, the interval change of the lesion on T2-weighted images was investigated.

Results: The characteristic DWI finding of cerebral fat embolism in the acute stage was multiple, hyperintense, dot-like lesions disseminated in the brain. These lesions were distributed dominantly in the bilateral border-zone areas. Some lesions had an ancillary location including the cortex, deep white matter, basal ganglia, and cerebellum. The lesions were more intense and numerous in DWI (b = 1000) than in DWI (b = 0). The findings on the follow-up T2-weighted images were multiple confluent hyperintense lesions in the white matter with progression since the initial MRI.

Conclusion: DWI could be a sensitive tool for detecting cerebral fat embolism in the acute phase. It is recommended that DWI be included in the initial evaluation of cerebral fat embolism with MRI.
Computed-tomography-guided punctures using a new guidance device
Authors: Magnusson A. , Radecka E. , Lönnemark M. , Raland H.
Published: September 2005

Purpose: To evaluate a new adjunctive guidance device, a puncture guide, constructed to simplify computed tomography (CT)-guided punctures and to make the procedure more accurate and safe.

Material and Methods: 17 patients referred for CT-guided punctures were included in the study. There were 10 thoracic and 7 abdominal or pelvic lesions with a mean maximum diameter of 29±18 mm. All punctures were performed using a laser guide combined with the new device. The needle guide created a streak artefact in the image, indicating the needle path.

Results: The puncture was successful at the first attempt in 15 of the 17 patients. The artefact was visible in all patients, and in the majority there was a distinct artefact reaching from the entry point to the lesion. The deviation between the angle of the streak artefact and the final angle of the needle was 1.1°.

Conclusion: The benefits of the puncture guide were the artefact pointing at the target, the needle support, and accuracy when performing CT-guided punctures.
Magnetic resonance imaging including magnetic resonance cholangiopancreatography for tumor localization and therapy planning in malignant hilar obstructions
Authors: Hänninen E. L. , Pech M. , Jonas S. , Ricke J. , Thelen A. , Langrehr J. , Hintze R. , Röttgen R. , Denecke T. , Winter L. , Neuhaus P. , Felix R.
Published: September 2005

Purpose: To assess image quality and overall accuracy of magnetic resonance imaging (MRI), including two magnetic cholangiopancreatography (MRCP) techniques, for the diagnostics and preoperative work-up of malignant hilar obstructions.

Material and Methods: Thirty-one patients with malignant hilar obstructions (hilar cholangiocarcinoma, n = 30; hepatocellular carcinoma, n = 1) received MRCP by two techniques (single-shot thick-slab and multisection thin-slice MRCP) and unenhanced and contrast material-enhanced MRI. MR assessment included the evaluation of image quality and visualization of bile ducts (5-point scale), and the classification of tumor status. MR results were subsequently correlated with the results from surgery and pathology.

Results: The maximum intensity projections of multisection thin-slice MRCP had significantly more artifacts compared to MRCP in the single-shot thick-slab technique, and overall image quality of single-shot thick-slab MRCP was rated significantly superior compared to multisection thin-slice MRCP (4.4±0.7 and 4.1±0.9, respectively). Moreover, ductal visualization of different parts of the biliary system was rated superior with single-shot thick-slab MRCP. In contrast, the original data from multisection thin slice MRCP facilitated visualization of periductal lesions and adjacent structures. Overall MR accuracy for the assessment of tumor status, periductal infiltration, and lymph node metastases was 90%, 87%, and 66%, respectively.

Conclusion: For evaluation of malignant hilar obstructions, MRCP by the single-shot thick-slab technique had superior image quality and fewer artifacts; in contrast, besides sole biliary visualization, multisection MRCP depicted complementary adjacent parenchymal and periductal structures. We therefore recommend MRI, with a combination of both MRCP techniques, for the diagnostic work-up and therapy planning of malignant hilar obstructions.
Where did all the land go? Enclosure & social struggle in Kivu (D.R.Congo)
Authors: Van Acker Frank
Published: September 2005

Kivu's traditional patrimonial system revolved around the distribution of access rights to communally held land in return for rents that were redistributed through the system. The social capital embedded in this institutional framework was a public good. The introduction of a ‘modern’ land law in 1973 destroyed the social cohesion of that patrimonial system; it sanctioned efforts to capitalise and appropriate the full value of these rents. At the time of the law's introduction, market mechanisms for factor markets including land, were not developed, so they had to be simulated. The core of this simulation consisted of exchanging social capital, built up in networks that involved political power-holders and state administrators, for assets. The social capital embedded in these networks was a ‘club good’ rather than a public good; both are non-rival in nature, but with a club good, unlike public goods, exclusion is workable. Its effect was therefore marginalisation and dispossession of those not belonging to the ‘club’, and the erosion of the existing social capital tied up in the traditional institutional framework by breaking the patterns of reciprocity and assurance featured in it. This evolution has contributed to a change of social structure and a crisis of legitimacy that increased social tensions and the potential for conflict. The customary leadership was able to cling to their positions by mobilising their clientele on an ethnic platform, conveniently using the issue of nationality: ‘foreigners’, especially the Banyarwanda and Banyamulenge, were accused of having unrightfully appropriated customary land and of having subverted the customary order.
Economic Sociology: The Recursive Economic System of J. S. Mill
Authors: Witztum Amos
Published: September 2005

In a recent paper, R. Ekelund and D. Walker (1996) argue that, “[i]ncentives, utilitarian principles, and the diffusion of property rights are the key to understanding Mill on the statics and dynamics of ‘equity and justice’”(p. 576). Their paper, which deals with John Stuart Mill's views on taxation, reads very much like a modern defense of popular capitalism. From the static point of view, it is imperative not to interfere with the internal relationship between economic variables and thus, distort incentives (proportional income tax). From the dynamic point of view, “inheritance taxes [are] the essential mechanism of an evolutionary change towards anefficiently functioning capitalism” (p. 578, italics added).