bluuebunny/crossref_metadata_2025 huggingface dataset:
A Theory of Land Prices when Land is Supplied Publicly: The Case of the Netherlands
Authors: Needham Barrie
Published: October 2006

Most attempts to explain land prices assume free competition between suppliers and demanders of land. If there are constraints on this competition (e.g. land-use planning) this is added as a modification to the theory. When, however, the supply of building land is in the hands of public agencies, which determine the volume and price of supply specified by land use and location, a different theoretical approach is needed. In this situation, certain economic principles apply which determine the maximum and minimum prices at which land will be bought for development and at which serviced building land will be supplied for development. However, both the limits of this range and the actual land prices within it will depend on political choices made by the public agencies. In the Netherlands, municipalities dominate the supply of land for development and redevelopment. Information about the way Dutch municipalities make the political choices and about the actual land prices there, suggests they make the political choices in a consistent way: they see themselves as suppliers of a public utility, namely building land. They try to supply so that there is never any scarcity, so that quality is high, so that prices no more than cover costs. The resulting prices might not be low, but they represent good value for money, because no-one reaps development gains directly. These are low because disposal prices are lower than could be realised, or development gains are absorbed in providing either a better quality of land servicing or more land for social uses.
Price Determinants of Foreclosed Urban Land
Authors: Asabere Paul K. , Huffman Forrest E.
Published: October 2006

Foreclosure proceedings are the primary cause of real-estate auction sales in the US. Given the added legal constraints and risk associated with foreclosure proceedings, it is an empirical question as to whether the resulting prices are a function of the usual underlying factors of physical characteristics, locational benefits and neighbourhood effects which motivate normal market sale pricing. Using a hedonic pricing model common in the analysis of market sale prices, we find systematically determined price behaviour which replicates market pricing
Methodological Issues in the Determination of the Quality of Life in Urban Areas
Authors: Stover Mark Edward , Leven Charles L.
Published: October 2006

This paper presents a model which illustrates the interaction between the labour and real estate markets in the determination of the value of local amenities. The primary purpose of this study is to examine the importance of functional form in measuring the quality of life (QOL) in urban areas. Using 1980 data on US urban counties, this specification provides new options for QOL estimates as an extension of previous work. This study also discusses the problems associated with summarising QOL in a one-dimensional monotonic ranking. One form of a multi-dimensional rating system is presented for comparison.
Urban Economic Development and High Technology Industry
Authors: Shachar Arie , Felsenstein Daniel
Published: October 2006

This paper examines the economic development prospects for urban areas arising from localised clusters of high technology activity. Economic development opportunities are expected to be expressed in the development of local linkage patterns: employment linkages, production and service linkages and linkages to local universities. On the basis of survey evidence of high technology firms from two urban areas in Israel, linkage patterns are found to be weakly developed locally but extensively developed nationally and internationally. This is explained as a result of the international character of Israeli high technology activity resulting in a limited effect on the development of the local urban economy. Policy implications for urban economic development point to the need for the formulation of a public policy executed and administered at the local level rather than the present system of central government targeting of urban economic development at select locations.
Producer Services and Systems of Flexible Production
Authors: Coffey William J. , Bailly Antoine S.
Published: October 2006

During the decade of the 1980s, regional science began to devote more and more attention to the influence of two phenomena upon the structure and functioning of the space-economy: (1) service activities, in general, and producer services, in particular, and (2) flexible production systems. This paper explores the extent to which these two major preoccupations of contemporary regional science can be integrated, and attempts to contribute to the understanding of the growth and location of producer services by examining the manner in which an analytical framework based upon flexible production may be applied to the latter. The exploration begins with a summary and criticism of the flexible production approach. This is followed by a discussion of the growth of producer services and of the trends towards the increasing externalisation of these activities. Next, the appropriateness of employing a flexible production framework in the case of producer services is examined. The significance of the concept of flexible production for understanding the location of producer services is then explored. Finally, the paper examines the effects upon the labour force of flexibility in the production and use of producer services.
Form Follows Function: Reformulating Urban Population Density Functions
Authors: Batty Michael , Sik Kim Kwang
Published: October 2006

In this paper, we argue that the most appropriate form for urban population density models is the inverse power function, contrary to conventional practice, which is largely based upon the negative exponential. We first show that the inverse power function has several theoretical properties which have hitherto gone unremarked in the literature. Our main argument, however, is based on the notion that a density function should describe the extent to which the space available for urban development is filled. To this end, we introduce ideas from urban allometry and fractal geometry to demonstrate that the inverse power model is the only function which embodies the fractal property of self-similarity which we consider to be a basic characteristic of urban form and density. In short, we show that the distance parameter a of the inverse power model is a measure of the extent to which space is filled, and that its value is determined by the basic relation D+α=2 where D is the fractal dimension of the city in question. We then test this model using four data sets which measure the density and morphology of the city of Seoul. Using a variety of estimation methods such as loglinear regression, dimensional approximation and entropy-maximising, we estimate dimension and density parameters for 136 variants of the function and its data sets. From these estimates, 125 are within the values hypothesised and this suggests fairly conclusively that the value of the density parameter a for the inverse power function should be within the range 0-1 and probably between 0.2 and 0.5. Many related questions are raised by this analysis which will form the subject of future research.
Urban Concentration and Agglomeration Economies: Re-examining the Relationship
Authors: Petrakos George C.
Published: October 2006

Using a sample of 49 countries and two-stage least squares estimators, the effects of urban concentration on economic growth are examined. Evidence is provided that external agglomeration economies in the largest cities have been exhausted, although the process of concentration continues to have a positive impact on output. This effect however is attributed to internal adjustments caused by concentration in factor intensity and marginal factor productivity in the production activities of urban areas. The results suggest that a meaningful policy aiming to alleviate the social costs of concentration in over-populated metropolises without reducing the overall efficiency of the economy, should follow a long-term strategy of developing smaller cities in the periphery and favouring the operation of smaller-scale, less capital-intensive enterprises in the economy.
Low-wage Workers in a High-technology Manufacturing Complex: The Southern Californian Electronics Assembly Industry
Authors: Scott Allen J.
Published: October 2006

The paper opens with a brief description of the electronics assembly industry in Southern California. A statistical profile of workers in the industry is presented. It is shown that the employment relation in this industry is characterised by much instability and mobility, though the industry also comprises a cadre of more steadily employed workers. A division of labour along gender and ethnic lines can be demonstrated to exist in the industry, with Asian males occupying more technical and responsible positions than Asian females and Hispanic males and females. Workers are shown to be strongly tied in their residential locations and job mobility patterns to fairly narrowly circumscribed local labour market areas. In sum, the paper sketches out a portrait of a secondary labour market in which job precariousness and social marginality exist side-by-side with a certain degree of internal differentiation and permanence.
The Location of Employment in High-technology Manufacturing in Great Britain
Authors: Fingleton Bernard
Published: October 2006

The location of employment in high-technology manufacturing in Great Britain in 1984 is analysed using a series of spatial regression models. These show that the distribution of employment explains a large part of the high-technology manufacturing employment distribution, indicating that the forces acting on high-technology location are similar to those acting on all industries. In addition, it is shown that the number of industrial establishments that migrated from each county in the previous decade is significantly positively associated with the location of high-technology manufacturing. This is interpreted as a signal that spatial variations in the level of positive feedback were also responsible for employment variations. In addition, the South West region has a higher level of employment than suggested by the above factors, and Yorkshire and Humberside and the Intermediate Areas have lower employment levels. There are four significant outliers from the final regression. An exploratory analysis suggests that three of these counties deviate because of sectoral effects involving a few high-technology subsectors, rather than being the result of local economic factors operating across the range of high-technology subsectors. London is a special case with less than the predicted level of high-technology employment, though the metropolis remained the country's major concentration of high-technology jobs.
The Fuzzy Industry Maturity Grid and its Application to the Singapore Property Sector
Authors: Tay Danny P. H. , Tham K.W. , David K. H. Ho
Published: October 2006

This paper introduces the fuzzy industry maturity grid as an extension of the industry maturity grid for diagnosing an economic sector or an industry, to identify fast-growing sectors and to map out growth strategies for sectors showing signs of maturity. By incorporating fuzzy set theory and aggregation models in decision-making, the conventional industry maturity grid is enhanced from a qualiative analysis to a semi-quantitative method which captures an expert's knowledge of the sector or industry, inclusive of his judgement. It does this via using a linguistic scale describing the characteristics under each of the three main dimensions of the IMG to form fuzzy sets; a hierarchical aggregation of information based on fuzzy aggregation operators; and a conceptual hypercube to determine the rank and ranking size of the perscribed strategies. The application of the fuzzy industry maturity grid is illustrated with an example on the Singapore property sector.
Population Density Gradients and Urbanisation Measurement
Authors: Alperovich Gershon , Deutsch Joeseph
Published: October 2006

The exponential density function has been used widely to describe and compare the patterning of urban population. In this article it is argued that the exponent within the function can be biassed by the misidentification of the CBD and of the centroids of census tracts. Using a least-squares method it is shown that such misspecification (of the location of the CBD) leads to an underestimation of the gradient, and shows that the magnitude of the bias is itself related to the extent of the distance error by which the CBD is misidentified.
The Economics of Planning Gain: a re-appraisal
Authors: Bowers John
Published: October 2006

This paper is a critical examination of certain aspects of the literature on the economics of planning gain. The principal question it addresses is whether the introduction of planning gain into the planning process is likely to enhance consumer welfare.
Squatting as Rent-seeking and Pressure-group Competition: A South African Case-Study
Authors: Nathan Cedric D. , Spindler Zane A.
Published: October 2006

A new squatting phenomenon in South Africa is analysed from a rent-seeking, pressure-group perspective. While such squatting may play an expanded role in privatising publicly- and even privately-held land and in redistributing wealth over the near future, in the longer term its expansion will tend to be limited by rent-protecting and counter-innovation as long as this rent-seeking competition stays within the bounds set by constitutional government.
Correlates of Commuting Patterns: A Case-study of Bangkok, Thailand
Authors: Punpuing Sureeporn
Published: October 2006

Commuting plays a causal role in the process of adjusting between residence and workplace. This paper examines the relationship between demographic, socio-economic and social environment factors and commuting patterns in Bangkok, Thailand. Based on the assumption that the commuting decision involves a two-step process—a decision to work at home or not, and a decision on commuting distance and time—the results indicated that age, sex, occupation and time spent living in current home were significantly associated with workplace location. Age and home-ownership status related to commuting time, and commuting distance related to occupation and home-ownership status. Furthermore, the analysis indicates that correlates of commuting patterns were largely explained by the set of socio-economic factors. Home-ownership status, however, had an important effect on commuting patterns.
A Theory of Urban Decline: Economy, Demography and Political Elites
Authors: Friedrichs Jiirgen
Published: October 2006

During the past decades, large cities in advanced industrialised countries have experienced different demographic and economic trajectories. Some are continuing to grow in population and jobs; many have experienced decline. To account for the process of decline and its consequences, a general model of urban decline is proposed. It specifies the relationship between employment, population, political élites and urban fiscal revenues. Constructs and propositions are drawn from economic and ecological theorems. Empirical evidence is based on literature predominantly from Germany and the US.
Berlin and the German Systems of Cities
Authors: Dangschat Jens S.
Published: October 2006

The formation of the European Single Market and unification in particular is shaking the hierarchy and system of German cities. This holds strongly for East German cities, but most for Berlin-the re-united city and the new capital of Germany. In the first part of the paper the developments of the two halves of the city between 1945 and 1989 are described under the topics of political development and planning, population, housing and economic development. The second part describes the problems of the creation of the German urban system at 1990/1991 right after unification, in the fields of planning and policy, finance, population and economy. The last part gives some sceptical spotlights on future developments in the aforementioned fields.
Segregation in Urban Space: A New Measurement Approach
Authors: Waldorf Brigitte S.
Published: October 2006

A variety of segregation measures have been proposed in the literature with the dissimilarity index and its variants being the most widely applied. While these measures provide a quick means of comparing segregation patterns across space and time, they are not linked to the processes that generate and maintain segregative patterns. This paper proposes a new method for measuring segregation. The method is based on comparative evaluations of neighbourhood characteristics as a determinant of spatial behaviour in cities. The proposed approach moves away from a purely geometric interpretation of segregation by anchoring the measurement of segregation into the actual urban setting. The method's main advantages are its responsiveness to changes in urban characteristics (e.g. spatial variations in rent increases), and changes in preference structures (e.g. a declining importance of distance as an impediment to relocation). A numerical example is used to demonstrate the behaviour of the proposed method against traditional segregation measures. The results indicate that the segregation experiences of minorities may be more severe than previously thought.
The Limitations of Planned Land Development for Low-income Housing in Third World Cities
Authors: Lowder Stella
Published: October 2006

The analysis of planning as an agency, in isolation from the politico-administrative, economic and social structures in which the process takes place, is particularly inappropriate in Third World cities with their grossly inadequate public and unevenly distributed private resources. Neither of the states examined here, embedded in an Islamic and a capitalist economy respectively, succeeded in including genuinely poor households in their schemes, even during periods of governments in command of resources and proclaiming that as their avowed intention. Despite the very different tenets of the societies examined, concern over the form of development, the mechanisms to achieve it and vested interests resulted in the exclusion of the poor.
The Local Income and Employment Impact of Lancaster University
Authors: Armstrong Harvey W.
Published: October 2006

The paper presents the results of an analysis, using Keynesian local open economy multipliers, of the impact of Lancaster University upon income and employment in the local city and surrounding hinterland area. The results of the University impact analysis are contrasted with similar analyses of Heysham 2 nuclear power station and two local manufacturing firms. The results of the impact analysis are used in a speculative manner to consider the effects of a planned expansion of student numbers at Lancaster in the 1990s.
Tinbergen-Bos Metricised Systems: Some Further Results
Authors: Kuiper F.J. , Kuiper J.H. , Paelinck J.H.P.
Published: October 2006

The paper describes a spatial economic equilibrium in which each market shows an equilibrium and the location of all producers is determined in an optimal way. Being a very general model, in order to solve it a number of hypotheses had to be introduced. We used the hypothesis of Tinbergen and Bos. The system is optimised in such a way that total transport costs are minimised. Many optimal solutions are shown for different numbers of firms per sector. It appears that the optimal location for a sector having a very limited number of firms, would be the centre of the region; if the number of firms increases, optimal locations will be found in a circle around the centre. The impact of economic variables—such as the propensity to consume-on the optimal location pattern of all firms, is also demonstrated.
Forecasting Provincial Business Indicator Variables and Forecast Evaluation
Authors: Talwar Prem P. , Chambers Edward J.
Published: October 2006

This paper evaluates a number of univariate and multivariate time-series forecasting models of selected indicator variables for three Canadian provinces: Alberta, British Columbia and Manitoba. The out of sample forecasts from these models are compared not only with themselves but with common indicators from the quarterly provincial forecast model of the Conference Board of Canada. The concepts of directional accuracy, the conditional efficiency, and the robust regression are used in evaluating the forecasts. In most cases, the strategy of combining forecasts produced superior results to those given by the Conference Board of Canada.
Urban Conservation in Singapore: A Survey of State Policies and Popular Attitudes
Authors: Kong Lily , Yeoh Brenda S. A.
Published: October 2006

This paper focuses on the intersection of state policies and popular attitudes towards urban conservation in Singapore. It first reviews changing state policies which have shaped the built environment from slum clearance in the 1950s and 1960s to the conservation of the city's historic districts in the 1980s and 1990s. It then explores the degree of convergence between the state and the public in terms of the meaning and purposes of conservation, the question of whose heritage to conserve and which strategies are appropriate. While there is general agreement on the need for conservation and the benefits it confers on the city, there are also divergences over specific issues such as the authenticity of the conserved landscape, the degree to which traditional trades and lifestyles can be retained, and the level to which public opinions are considered in state planning.
Globalisation, Regulation, Urbanisation: The Case of the Netherlands
Authors: Thrift Nigel
Published: October 2006

This paper traces some of the linkages between globalisation and social regulation via the example of the Netherlands. The paper is in four main sections. The first section considers recent debates on globalisation through an attempt to identify key economic processes. The second section considers the main objections that have been made to the globalisation thesis, and especially its lack of attention to matters of social regulation. The third section considers the way in which the Dutch economy has been able to become comparatively successful through a judicious blend of globalisation and social regulation. The final section of the paper then considers the special role of the Randstad in promoting this concordat.
Histopathology of the Lymph Nodes
Authors: Elmore Susan A.
Published: October 2006

Lymph nodes function as filters of tissues and tissue fluids and are sites of origin and production of lymphocytes for normal physiological functions. As part of this normal function, they react to both endogenous and exogenous substances with a variety of specific morphological and functional responses. Lesions can be both proliferative and nonproliferative, and can be treatment-related or not. The histological evaluation of lymph nodes is necessary in order to understand the immunotoxic effects of chemicals with the resulting data providing an important component of human risk assessment. It is the challenge of the toxicologic pathologist to interpret the pathology data within the complete clinical evaluation of the entire animal. Daily insults, ageing and toxins can alter the normal histology and primary function of lymph nodes. Therefore it is important to distinguish and differentiate lesions that occur naturally during normal development and ageing from those that are induced by xenobiotics. To achieve this goal, comparison with strain- age- and sex-matched controls is crucial.
Temporal Order of Strokes Primes letter Recognition
Authors: Parkinson Jim , Khurana Beena
Published: October 2006

Does the perception of objects that are the result of human actions reflect the underlying temporal structure of the actions that gave rise to them? We tested whether the temporal order of letter strokes influences letter recognition. In three experiments, participants were asked to identify letters that temporally unfolded as an additive sequence of letter strokes, either consistent or inconsistent with common writing action. Participants were significantly faster to identify letters from consistent temporal sequences, indicating that the initial part of the sequence contained sufficient information to prime letter recognition. We suggest that letter perception reflects the temporal structure of letter production; in other words, Simon sees as Simon does.
Management of an Outbreak ofClostridium difficile–Associated Disease Among Geriatric Patients
Authors: Cherifi S. , Delmee M. , Broeck J. Van , Beyer I. , Byl B. , Mascart G.
Published: October 2006

Objective.

To describe a nosocomial outbreak ofClostridium difficile–associated disease (CDAD).

Design.

A traditional outbreak investigation.

Setting.

Geriatric department of a tertiary care teaching hospital from March through April 2003.

Methods.

The outbreak was detected by theC. difficilesurveillance program of the infection control unit. CDAD was diagnosed by stool culture and fecal toxin A detection with a qualitative rapid immunoassay. Isolates ofC difficilewere serotyped and genotyped using pulsed-field gel electrophoresis.

Results.

The incidence of CDAD increased from 27 cases per 100,000 patient-days in the 6-month period before the outbreak to 99 cases per 100,000 patient-days during the outbreak. This outbreak involved 21 of 92 patients in 4 geriatric wards, which were located at 2 geographically distinct sites and staffed by the same medical team. The mean age of patients was 83 years (range, 71-100 years). Five (24%) of the 21 patients had community-acquired diarrhea, and secondary hospital transmission resulted in 3 clusters involving 16 patients. Serotyping and genotyping were performed on isolates in stool specimens from 19 different patients; 16 of these isolates were serotype A1, whereas 3 displayed profiles different from the outbreak strain. Management of this outbreak consisted in reinforcement of contact isolation precautions for patients with diarrhea, cohorting of infected patients in the same ward, and promotion of hand hygiene. Relapses occurred in 6 (29%) of 21 patients.

Conclusion.

Control of this rapidly developing outbreak of CDAD was obtained with early implementation of cohorting and ward closure and reinforcement of environmental disinfection, hand hygiene, and enteric isolation precautions.
Impact of Extended-Spectrum β-Lactamase–Producing Escherichia coli and Klebsiella Species on Clinical Outcomes and Hospital Costs: A Matched Cohort Study
Authors: Lee Su Young , Kotapati Srividya , Kuti Joseph L. , Nightingale Charles H. , Nicolau David P.
Published: October 2006

Objectives.

To evaluate the economic and clinical impact of infection with extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella species (ESBL-EK).

Design.

A matched-cohort analysis of the cost of illness.

Setting.

An 810-bed, urban, community hospital in Hartford, Connecticut.

Patients.

Twenty-one case patients infected with ESBL-EK at a site other than the urinary tract were matched with 21 control subjects infected with a non–ESBL-producing organism on the basis of pathogen species, age, anatomic site of infection, hospitalization in the intensive care unit (ICU) during the time of infection, date of hospitalization, and initial antibiotics received.

Results.

Mean infection-related costs per patient were significantly greater for case patients than for control patients ($41,353 vs $24,902; P = .034). Infection-related length of stay was the main driver of cost, which was prolonged for case patients, compared with control patients (21 vs 11 days; mean difference, 9.7 days [95% confidence interval {CI}, 3.2-14.6 days] P = .006). The additional cost attributed to the presence of an ESBL-EK infection was $16,450 per patient (95% CI, $965-$31,937). Case patients were more likely than control patients to have clinical failure (P = .027), and the rate of treatment success for case patients whose initial treatment involved antibiotics other than carbapenems was lower than that for their matched control patients (39% vs 83%; P = .013). Treatment was successful in patients for whom initial treatment was with a carbapenem, regardless of the ESBL status of the pathogen.

Conclusion.

The cost of non–urinary tract infections caused by ESBL-EK was 1.7 times the cost of non–urinary tract infections caused by non-ESBL producers. Prompt recognition and appropriate antimicrobial selection may minimize this ESBL-related impact on hospital costs.
Knowledge, Attitudes, and Behaviors Regarding Piperacillin-Tazobactam Prescribing Practices: Results From a Multicenter Study
Authors: Antoine Theresa L. , Curtis Amy B. , Blumberg Henry M. , DeSilva Kathryn , Fransua Mesfin , Gould Carolyn V. , King Mark , Kraman Alice A. , Pack Jan , Ribner Bruce , Seybold Ulrich , Steinberg James P. , Wells Jane B. , Sinkowitz-Cochran Ronda L. , Cardo Denise , Jernigan John A. , Gaynes Robert P.
Published: October 2006

We investigated knowledge, attitudes, and behaviors of prescribers concerning piperacillin-tazobactam use at 4 Emory University-affiliated hospitals. Discussions during focus groups indicated that the participants' perceived knowledge of clinical criteria for appropriate piperacillin-tazobactam use was inadequate. Retrospective review of medical records identified inappropriate practices. These findings have influenced ongoing interventions aimed at optimizing piperacillin-tazobactam use.
Outbreak ofSerratia marcescensColonization and Infection Traced to a Healthcare Worker With Long-Term Carriage on the Hands
Authors: Vries Jutte J. C. de , Baas Willy H. , Ploeg Kees van der , Heesink Albêrt , Degener John E. , Arends Jan P.
Published: October 2006

Objective.

To reveal the source of a nosocomial outbreak of colonization and infection with a strain ofSerratia marcescenspositive for Guiana extended-spectrumβ-lactamase 1 (GES-1) that occurred among patients in a neurosurgical intensive care unit (ICU) in a Dutch university medical center from May 2002 through March 2003.

Methods.

Samples from the environment and from the hands of healthcare workers (HCWs) were cultured. A retrospective case-control study was carried out.

Results.

Fifteen neurosurgical ICU patients who had 1 or more cultures that yielded the epidemic strain ofS. marcescensfrom May 2002 through March 2003 were defined as case patients and matched with 30 control patients. Environmental cultures did not reveal a prominent source ofS. marcescens. Cultures of specimens from the hands of 100 HCWs revealed colonization of a single HCW with the epidemic strain. Although this HCW instantly went on leave, serial cultures detected prolonged carriage of the epidemic strain on the hands of the HCW for 3 months. The skin of the HCW's hands was psoriatic. The epidemic abruptly ended after the colonized HCW went on leave. Retrospective case-control analysis showed that the patients colonized or infected withS. marcescensreceived significantly more nursing care from the colonized HCW than did control patients (P<.05). From February 2004 through October 2004, a second cluster of 3 patients was detected with the epidemic strain ofS. marcescens. In October 2004, the formerly colonized HCW appeared to have carriage of the epidemic strain on the hands again.

Conclusions.

A single HCW with the epidemic strain ofS. marcescenson the hands was considered the source of this outbreak.
Experimental Evaluation of an Automated Endoscope Reprocessor With In Situ Generation of Peracetic Acid for Disinfection of Semicritical Devices
Authors: Sattar Syed A. , Kibbee Richard J. , Tetro Jason A. , Rook Tony A.
Published: October 2006

Objective.

To evaluate the effectiveness of a high-level disinfection solution generated inside an endoscope processing system for decontaminating external and internal surfaces of experimentally contaminated heat-sensitive medical devices.

Methods.

The American Society for Testing and Materials Simulated-Use Test protocol (E1837-02), which incorporates a soil load in each inoculum, was used to evaluate the efficacy of the system when processing 4 common types of endoscopes contaminated separately with 5 types of nosocomial pathogens: Pseudomonas aeruginosa (ATCC 15442), spores of Clostridium difficile (ATCC 9689), a glutaraldehyde-resistant strain of Mycobacterium chelonae, a vancomycin-resistant strain of Enterococcus faecalis, and a methicillin-resistant strain of Staphylococcus aureus. Rinse solution samples from channels and from surfaces of the processed endoscopes were tested for any microbicidal residues.

Results.

For all organisms tested, the baseline level of contamination of the endoscopes ranged from 5 log10 to greater than 7 log10 at each external surface site and internal channel. All tests showed reductions in viability of the test organisms to undetectable levels. All rinse solution samples from external and internal sites of the endoscopes proved to be free of any residual microbicidal activity.

Conclusions.

The endoscope reprocessor, with its processor-generated high-level disinfection solution, successfully reduced the numbers of selected, clinically relevant pathogens to undetectable levels both in the channels and on the outside surfaces of the 4 representative endoscopes tested in this study.
Factors That Influence Influenza Vaccination Among Healthcare Workers in a French Geriatric Hospital
Authors: Trivalle Christophe , Okenge Edouard , Hamon Brigitte , Taillandier Jean , Falissard Bruno
Published: October 2006

In a geriatric hospital in France, only 80 (21%) of 390 healthcare workers (HCWs) were vaccinated against influenza. Predictive factors for accepting influenza vaccination were occupation as a physician (odds ratio [OR], 9.79), previous receipt of influenza vaccination (OR, 36), and desire to protect their own health (OR, 2.42) and residents' health (OR, 3.68). Predictive factors for refusing influenza vaccination were occupation as a nurse (OR, 6.41) or nursing assistant (OR, 4.04) and belief that homeopathic medication is more effective than the vaccine (OR, 5.75).
PROTERAN: animated terrain evolution for visual analysis of patterns in protein folding trajectory
Authors: Zhou Ruhong , Parida Laxmi , Kapila Kush , Mudur Sudhir
Published: October 2006

Summary: The mechanism of protein folding remains largely a mystery in molecular biology, despite the enormous effort from many groups in the past decades. Currently, the protein folding mechanism is often characterized by calculating the free energy landscape versus various reaction coordinates such as the fraction of native contacts, the radius of gyration and so on. In this paper, we present an integrated approach towards understanding the folding process via visual analysis of patterns of these reaction coordinates. The three disparate processes (1) protein folding simulation, (2) pattern elicitation and (3) visualization of patterns, work in tandem. Thus as the protein folds, the changing landscape in the pattern space can be viewed via the visualization tool, PROTERAN, a program we developed for this purpose. We first present an incremental (on-line) trie-based pattern discovery algorithm to elicit the patterns and then describe the terrain metaphor based visualization tool. Using two example small proteins, a β-hairpin and a designed protein Trp-cage, we next demonstrate that this combined pattern discovery and visualization approach extracts crucial information about protein folding intermediates and mechanism.

Contact:  ruhongz@us.ibm.com

Supplementary information:
Delay in fishery management: diminished yield, longer rebuilding, and increased probability of stock collapse1
Authors: Shertzer Kyle W. , Prager Michael H.
Published: October 2006

Shertzer, K. W., and Prager, M. H. 2007. Delay in fishery management: diminished yield, longer rebuilding, and increased probability of stock collapse. ICES Journal of Marine Science, 64: 149–159. When a stock is depleted, catch reductions are in order, but typically they are implemented only after considerable delay. Delay occurs because fishery management is political, and stricter management, which involves short-term economic loss, is unpopular. Informed of stock decline, managers often hesitate, perhaps pondering the uncertainty of scientific advice, perhaps hoping that a good year class will render action moot. However, management delay itself can have significant costs, when it exacerbates stock decline. To examine the biological consequences of delay, we simulated a spectrum of fisheries under various degrees of delay in management. Increased delay required larger catch reductions, for more years, to recover benchmark stock status (here, spawning-stock biomass at maximum sustainable yield). Management delay caused stock collapse most often under two conditions: (1) when the stock–recruitment relationship was depensatory, or (2) when catchability, unknown to the assessment, was density-dependent and fishing took juveniles. In contrast, prompt management resulted in quicker recoveries and higher cumulative yields from simulated fisheries. Benefits to stock biomass and fishery yield can be high from implementing management promptly.
Towards blueprints for network architecture, biophysical dynamics and signal transduction
Authors: Coombes Stephen , Doiron Brent , Josić Krešimir , Shea-Brown Eric
Published: October 2006

We review mathematical aspects ofbiophysical dynamics,signal transductionandnetwork architecturethat have been used to uncover functionally significant relations between the dynamics of single neurons and the networks they compose. We focus on examples that combine insights from these three areas to expand our understanding of systems neuroscience. These range from single neuron coding to models of decision making and electrosensory discrimination by networks and populations and also coincidence detection in pairs of dendrites and dynamics of large networks of excitable dendritic spines. We conclude by describing some of the challenges that lie ahead as the applied mathematics community seeks to provide the tools which will ultimately underpin systems neuroscience.
New ‘phase’ of quantum gravity
Authors: Wang Charles H.-T
Published: October 2006

The emergence of loop quantum gravity over the past two decades has stimulated a great resurgence of interest in unifying general relativity and quantum mechanics. Among a number of appealing features of this approach is the intuitive picture of quantum geometry using spin networks and powerful mathematical tools from gauge field theory. However, the present form of loop quantum gravity suffers from a quantum ambiguity, owing to the presence of a free (Barbero–Immirzi) parameter. Following the recent progress on conformal decomposition of gravitational fields, we present a new phase space for general relativity. In addition to spin-gauge symmetry, the new phase space also incorporates conformal symmetry making the description parameter free. The Barbero–Immirzi ambiguity is shown to occur only if the conformal symmetry is gauge fixed prior to quantization. By withholding its full symmetries, the new phase space offers a promising platform for the future development of loop quantum gravity. This paper aims to provide an exposition, at a reduced technical level, of the above theoretical advances and their background developments. Further details are referred to cited references.
Nonlinear dynamics as an essential tool for non-destructive characterization of soft nanostructures using tapping-mode atomic force microscopy
Authors: Dankowicz Harry
Published: October 2006

Tapping-mode atomic force microscopy provides a means for successful and non-intrusive characterization of soft physical and biological structures at the nanoscale. Its full potential can only be realized, provided that the response of the oscillating probe tip to the strongly nonlinear, near-field force interactions with the structure and the intermittency of contact can be accurately modelled, analysed, controlled and interpreted. To this end, this paper reviews some experimental observations of fundamentally nonlinear behaviour of the tip dynamics. It discusses the nonlinear phenomenology that explains their presence in the tapping-mode operation of the atomic force microscope. Particular emphasis is placed on the coexistence of different steady-state responses and their origin in transitions across regions of rapidly varying force characteristics. The heuristics of a recently developed method for treating such transitions are presented and insights into its implications are drawn from related micro- and nanoscale applications.
Emerging frontiers in the physical sciences
Authors: Thompson J. Michael T , Wang Charles H.-T
Published: October 2006

This article overviews the contributions to the special Christmas Issues of
Phil. Trans. R. Soc. A
published in Decembers 2004–2006, which together cover most of the physical sciences. It also plays the role of a
Preface
for the 2006 issue, which is devoted to the work of young scientists in mathematics and physics.
TESTING RESISTANCE OF ENAMELED SURFACES TO SCRATCHING GOUGING, AND ABRASION*
Authors: Petersen F. A.
Published: October 2006

Abstract

Seven types of cover‐coat enamels were tested for resistance to scratching, gouging, and abrasion by various methods. These methods were (a) P.E.I. abrasion test, (b) P.E.I. gouge test, (c) variations of the gouge test, (d) Taber Abraser, and (e) a scratch test. Chemical durability and reflectance were found to have little or no correlation with the resistance of the enamels to abrasion.

The bubble structure of the enamel layer seemed to have the greatest effect on abrasion and scratch resistance of the enamel layer.
Profiling of apoptosis genes allows for clinical stratification of primary nodal diffuse large B‐cell lymphomas
Authors: Muris J. J. F. , Ylstra B. , Cillessen S. A. G. M. , Ossenkoppele G. J. , Kluin‐Nelemans J. C. , Eijk P. P. , Nota B. , Tijssen M. , De Boer W. P. H. , Van De Wiel M. , Van Den Ijssel P. R. L. A. , Jansen P. , De Bruin P. C. , Van Krieken J. H. J. M. , Meijer G. A. , Meijer C. J. L. M. , Oudejans J. J.
Published: October 2006

Intrinsic resistance of lymphoma cells to apoptosis is a probable mechanism causing chemotherapy resistance and eventual fatal outcome in patients with diffuse large B cell lymphomas (DLBCL). We investigated whether microarray expression profiling of apoptosis related genes predicts clinical outcome in 46 patients with primary nodal DLBCL. Unsupervised cluster analysis using genes involved in apoptosis (n = 246) resulted in three separate DLBCL groups partly overlapping with germinal centre B‐lymphocytes versus activated B‐cells like phenotype. One group with poor clinical outcome was characterised by high expression levels of pro‐and anti‐apoptotic genes involved in the intrinsic apoptosis pathway. A second group, also with poor clinical outcome, was characterised by high levels of apoptosis inducing cytotoxic effector genes, possibly reflecting a cellular cytotoxic immune response. The third group showing a favourable outcome was characterised by low expression levels of genes characteristic for both other groups. Our results suggest that chemotherapy refractory DLBCL are characterised either by an intense cellular cytotoxic immune response or by constitutive activation of the intrinsic mediated apoptosis pathway with concomitant downstream inhibition of this apoptosis pathway. Consequently, strategies neutralising the function of apoptosis‐inhibiting proteins might be effective as alternative treatment modality in part of chemotherapy refractory DLBCL.
Co‐expression of ghrelin and its receptor in pancreatic endocrine tumours
Authors: Ekeblad Sara , Lejonklou Margareta Halin , Grimfjärd Per , Johansson Térèse , Eriksson Barbro , Grimelius Lars , Stridsberg Mats , Stålberg Peter , Skogseid Britt
Published: October 2006

Objective  Expression of ghrelin has been reported in pancreatic endocrine tumours, but data on ghrelin receptor protein expression are lacking. The aim of this study was to examine the ghrelin receptor, as well as ghrelin, in a selected series of these tumours, including multiple endocrine neoplasia 1 (MEN1) associated tumours, and to correlate data with clinical features including body mass index.

Design  Immunohistochemical detection of ghrelin and its receptor was performed on frozen tissue from 31 tumours: 9 MEN1 and 22 sporadic. Twenty tumours were analysed by quantitative PCR. Plasma ghrelin was assessed in 26 patients.

Results  Twenty‐one (68%) of 31 tumours showed immunoreactivity for ghrelin (8/9 MEN1) and 19/20 expressed ghrelin mRNA. Ghrelin receptor protein was detected in 21/30 (70%) tumours (4/8 MEN1), and mRNA was detected in all analysed tumours. Insulinomas had significantly higher levels of receptor mRNA than other tumours. Five patients had elevated plasma ghrelin (> 2 SD above the control group mean). No significant difference in mean plasma ghrelin levels was found between patients (908 ± 569 ng/l) and controls (952 ± 164 ng/l). Mean BMI was 24·3 kg/m2. There was no association between ghrelin or receptor expression and survival.

Conclusions  We report the first immunohistochemical data on expression of the ghrelin receptor in pancreatic endocrine tumours: 70% of tumours in our material. Concomitant ghrelin and receptor expression was seen in 50% of tumours, indicating an autocrine loop. Ghrelin was expressed in 68% of tumours (8/9 MEN1). Despite frequent ghrelin expression, elevated circulating ghrelin is rare in these patients.
An assessment of rubber dam usage amongst specialists in paediatric dentistry practising within the UK
Authors: SOLDANI FRANCESCA , FOLEY JENNIFER
Published: October 2006

Objective. Rubber dam is recommended by the British Society of Paediatric Dentistry (BSPD) for various restorative and endodontic procedures. To date, there has been no report of actual usage of rubber dam within the speciality of paediatric dentistry. The aim of this study was to assess the usage of rubber dam amongst paediatric dentistry specialists within the UK.

Methods. A postal questionnaire was distributed to all practitioners registered on the UK General Dental Council's 2004 specialist list in paediatric dentistry.

Results. Data were available for 162 questionnaires (a 75% response rate), and of these, 85% of respondents worked in the National Health Service (NHS), 4% were private practitioners and the remainder had a mixed NHS/private practice. Regarding the benefits of rubber dam, 65% and 52% of respondents quoted patient safety and moisture control, respectively. Perceived difficulties of dam usage were lack of patient cooperation and the non‐necessity for a particular treatment, as quoted in 64% and 36% of the completed questionnaires, respectively. The most common modes of isolation for anterior and posterior teeth were Dry Dam® (58%), and clamp and dam (80%), respectively.

Conclusion. Current BSPD guidelines recommend rubber dam usage for many restorative procedures; however, it would appear that there is wide variability in the application, as well as under‐use, of rubber dam.