Application of the zero-range potential model to positron annihilation on molecules

In this paper we use a zero-range potential (ZRP) method to model positron interaction with molecules. This allows us to investigate the e?ect of molecular vibrations on positron–molecule annihilation using the van der Waals dimer Kr2 as an example. We also use the ZRP to explore positron binding to polyatomics and examine the dependence of the binding energy on the size of the molecule for alkanes. We ?nd that a second bound state appears for a molecule with ten carbons, similar to recent experimental evidence for such a state emerging in alkanes with twelve carbons.

Comparison of positron-impact vibrational excitation cross sections with the Born-dipole model

The development of cold trap-based positron beams and new scattering techniques has recently enabled the ?rst measurements of state-resolved positron-impact vibrational excitation cross sections. These measurements revealed a number of features worth further consideration, such as relatively sharp increases near threshold. This paper describes a comparison of the magnitudes and shapes of these cross sections with the predictions of the Born-dipole model. Agreement of the magnitudes of the cross sections varies widely, ranging from reasonable to excellent agreement for CO2 and CF4 to poor agreement for CO and CH4. In contrast, the energy dependence of these cross sections in all these cases is close to that predicted by the Born model.

Interfacial shear strength and tensile properties of injection-molded, short- and long-glass fiber-reinforced polyamide 6,6 composites

Injection-molded short- and long-glass fiber/polyamide 6,6 composites were subjected to tensile tests. To measure the effectiveness of the fibers in reinforcing the composites, a computational approach was employed to compute the fiber– matrix ISS, orientation factor, reinforcement efficiency, tensile-, and fiber length-related properties. Although the LFCs showed great improvement in fiber characteristics compared to the SFCs, enhancement in tensile properties was small, which is believed to be due to the larger fiber diameter. Kelly–Tyson model provides good approximation for the computation of ISS and tensile-related properties.

Current and possible future methods of assessing the activities of photocatalyst films

The continuing interest in semiconductor photochemistry, SPC, and the emergence of commercial products that utilise films of photocatalyst materials, has created an urgent need to agree a set of methods for assessing photocatalytic activity and international committees are now meeting to address this issue. This article provides a brief overview of two of the most popular current methods employed by researchers for assessing SPC activity. and one which has been published just recently and might gain popularity in the future, given its ease of use. These tests are: the stearic acid (SA) test, the methylene blue (MB) test and the resazurin (Rz) ink test, respectively. The basic photochemical and chemical processes that underpin each of these tests are described, along with typical results for laboratory made sol-gel titania films and a commercial form of self-cleaning glass, Activ (TM). The pros and cons of their future use as possible standard assessment techniques are considered. (C) 2007 Elsevier B.V. All rights reserved.

Bystander responses induced by low LET radiation

Radiation-induced bystander responses are observed when cells respond to their neighbours being irradiated. Considerable evidence is now available regarding the importance of these responses in cell and tissue models. Most studies have utilized two approaches where either a media-transferable factor has been assessed or cells have been exposed to low fluences of charged particles, where only a few percent are exposed. The development of microbeams has allowed nontargeted responses such as bystander effects to be more carefully analysed. As well as charged particle microbeams, X-ray microprobes have been developed, and several groups are also developing electron microbeams. Using the Gray Cancer Institute soft X-ray microprobe, it has been possible to follow the response of individual cells to targeted low doses of carbon-characteristic soft X-rays. Studies in human fibroblasts have shown evidence of a significant radiation quality-dependent bystander effect, measured as chromosomal damage in the form of micronuclei which is radiation quality dependent. Other studies show that even under conditions when only a single cell is targeted with soft X-rays, significant bystander-mediated cell killing is observed. The observation of bystander responses with low LET radiation suggests that these may be important in understanding radiation risk from background levels of radiation, where cells observe only single electron track traversals. Also, the indirect evidence for these responses in vivo indicates that they may have a role to play in current radiotherapy approaches and future novel strategies involving modulating nontargeted responses.

From bit level systolic arrays to HDTV processor chips

The initial part of this paper reviews the early challenges (c 1980) in achieving real-time silicon implementations of DSP computations. In particular, it discusses research on application specific architectures, including bit level systolic circuits that led to important advances in achieving the DSP performance levels then required. These were many orders of magnitude greater than those achievable using programmable (including early DSP) processors, and were demonstrated through the design of commercial digital correlator and digital filter chips. As is discussed, an important challenge was the application of these concepts to recursive computations as occur, for example, in Infinite Impulse Response (IIR) filters. An important breakthrough was to show how fine grained pipelining can be used if arithmetic is performed most significant bit (msb) first. This can be achieved using redundant number systems, including carry-save arithmetic. This research and its practical benefits were again demonstrated through a number of novel IIR filter chip designs which at the time, exhibited performance much greater than previous solutions. The architectural insights gained coupled with the regular nature of many DSP and video processing computations also provided the foundation for new methods for the rapid design and synthesis of complex DSP System-on-Chip (SoC), Intellectual Property (IP) cores. This included the creation of a wide portfolio of commercial SoC video compression cores (MPEG2, MPEG4, H.264) for very high performance applications ranging from cell phones to High Definition TV (HDTV). The work provided the foundation for systematic methodologies, tools and design flows including high-level design optimizations based on "algorithmic engineering" and also led to the creation of the Abhainn tool environment for the design of complex heterogeneous DSP platforms comprising processors and multiple FPGAs. The paper concludes with a discussion of the problems faced by designers in developing complex DSP systems using current SoC technology. © 2007 Springer Science+Business Media, LLC.

“Boundary-setting as a core activity in complex public systems”

Title: Boundary-setting as a core activity in complex public systems
Authors: Joanne Murphy & Mary Lee Rhodes

The definition of the boundary of a system is at the core of any systems approach (Midgley 2000; 2003). By defining boundaries we enable – and delimit – the range of outcomes sought and the actions and resources that can be brought to bear. In complex adaptive systems (CAS) analysis, the conceptualisaion and definition of boundaries is particularly challenging as they are constantly undergoing redefinition through agent action, interaction and entry/exit. (Rhodes et al 2011). The concept of ‘boundaries’ appears regularly in a wide range of literature around public management, administration, geopolitics, regeneration and organisational development. Discussions around boundaries focus on many things from concrete physical manifestations and barriers, to virtual interfaces between one organisational unit and another, or even entirely theoretical demarcations between different schools of thought (Kaboolian, 1998, Levi-Faur, 2004, Agranoff & McGuire, 2004).

However, managing ‘beyond’ such boundaries is a routinely recurring aspiration that transcends sectors and local concerns. Unsurprisingly then, there is an increasing understanding of the need to acknowledge and manage such boundaries (whether they be physical, social or organisational) within public management as a discipline (Currie et al 2007, Fitzsimmons and White, 1997, Murtagh, 2002). This paper explores the impact of boundaries on public management strategic decision-making in the sectors of urban regeneration and healthcare. In particular, it focuses on demarcations to physical space, communal identity and within professional relationships in these sectors.

The first section describes the research that gave rise to the paper and the cases examined. Next we briefly define what we mean by boundaries. We explore issues that have emerged from our analysis of urban regeneration and health care singularly, before looking at how the concept of boundaries is a recurrent concern across the sectors. The main contribution of the paper is an exploration of how a CAS lens can bring a new insight into the concept of boundaries and decision-making in the two sets of case studies. This discussion will concentrate on initial conditions, bifurcation and adaptation as key CAS factors in relation to boundaries. We conclude with a brief discussion on the benefits of a CAS lens to an analysis of boundaries in public management decision-making.
References:

Agranoff, R. and McGuire, M. (2003) Collaborative Public Management: Strategies for Local Government. Washington, DC: Georgetown Univ. Press.

Currie, G., Lockett, A. (2007) “A critique of transformational leadership: moral, professional & contingent dimensions of leadership within public services organizations”. Human Relations 60: 341-370.

Fitzsimmons and White, (1997) "Crossing boundaries: communication between professional groups", Journal of Management in Medicine, Vol. 11 Iss: 2, pp.96 – 101

Kaboolian, L. (1998) “The New Public Management: Challenging the Boundaries of the Management vs. Administration Debate” Public Administration Review Vol. 58, No. 3 pp.189-193

Levi-Faur D. and Vigoda-Gadot Eran (eds) (2004) International Public Policy and Management: Policy Learning Beyond Regional, Cultural and Political Boundaries, Marcel Dekker,
Midgley, G. (ed) (2003) Systems Thinking. London: Sage Publications

Midgley, G. (2000) Systemic Intervention: Philosophy, Methodology and Practice. New York, NY: Kluwer.

Murtagh, B. (2002). The Politics of Territory: Policy and Segregation in Northern Ireland. Basingstoke, Palgrave.

Rhodes, ML, Joanne Murphy, Jenny Muir, John Murray (2011) Public Management & Complexity Theory: Richer Decision Making in Irish Public Services, UK: Routledge

A tubular direct methanol fuel cell with Ti mesh anode

A novel tubular cell structure for a direct methanol fuel cell (DMFC) is proposed based on a tubular Ti mesh and a Ti mesh anode. A dip coating method has been developed to fabricate the cell. The characterization of the tubular MEA has been analyzed by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), half cell and single cell testing. The tubular DMFC single cell comprises: a Ti mesh, a cathode diffusion layer and catalyst layer, a Nafion recast membrane and a PtRuO/Ti anode. Half cell tests show that the optimum catalyst loading, Ru/(Ru + Pt) atomic ratio and the Nafion loading of a PtRuO/Ti mesh anode are: 4 mg cm, 38% and 0.6 mg cm, respectively. Single cell tests show that the Nafion loading of the recast Nafion membrane and the concentration of the methanol in the electrolyte have a major influence on cell performance. © 2006 Elsevier B.V. All rights reserved.

Promoting multicultural education in the primary classroom:Broadband videoconferencing facilities and digital video

The aim of this study was to explore the impact of interaction (through gathering local field data and engaging in remote reciprocal presentations) on aspects of multicultural awareness. Sixty-six 11-12-year-old Scottish primary school pupils collected data in the field from their local community through questionnaires, interviews, direct observation, digital images and video. From this they distilled a multimedia presentation, delivered by videoconference to a partner school in the USA, who reciprocated. There was some evidence of pre-post project gains in the complexity of the children's perceptions of their community environment, the ethnicity of their community, their own ethnicity, and news images. The children's use of language to define ethnicity also became more complex and their attitudes toward ethnic minorities became more inclusive. The implications for practice, policy and future research were explored. © 2004 Elsevier Ltd. All rights reserved.

Impact of prosthodontic rehabilitation on the chewing efficiency of partially dentate older patients

Objectives: This study compared two tooth replacement strategies for partially dentate older patients namely; removable partial dentures (RPDs) and functionally orientated treatment based on the shortened dental arch (SDA) concept. Patients were compared in terms of chewing efficiency after prosthodontic rehabilitation. Methods: Chewing efficiency was assessed electronically by a two-colour gum-mixing test. Specimens were assembled from two different colours of chewing gums with a size of 30 x 18 x 3 mm. After participants chewed for 20 cycles, the gum was retrieved, flattened to a 1-mm-thick wafer, and digitized with a flatbed image scanner. The pixels of unmixed colour in the specimen were counted by means of Adobe Photoshop 2.0R software (Adobe Systems, San Jose, CA, USA), and the ratio to the pixels of the entire frame was computed. This ratio is called the Unmixed Fraction (UF). The more efficiently the specimen is chewed, the less unmixed colour remains, and the smaller the gum becomes. Consequently, a low unmixed fraction corresponds to good chewing efficiency. Results: 32 patients completed the chewing efficiency test (17 RPDs and 15 SDA). The mean UF recorded for the SDA group was not significantly different to that recorded for the RPD group (p>0.05, unpaired t-test). Conclusion: These results indicate that prosthodontic rehabilitation according to the principles of the SDA is equivalent to RPDs in terms of restoration of chewing ability for partially dentate older patients.

Economic evaluation and its place in dentistry

Objective: This review intends to examine current research surrounding economic assessment in the delivery of dental care. Economic evaluation is an acknowledged method of analysing dental care systems by means of efficiency, effectiveness, efficacy and availability. Though this is a widely used method in medicine, it is underappreciated in dentistry. As the delivery of health care changes there has been recent demand by the public, the profession, and those funding dental treatment to investigate current practices regarding programs themselves and resource allocation.
Methods: A meta-analysis was conducted regarding health economics. The initial search was carried out using Pubmed, Google Scholar, Science Direct, and The Cochrane Library with search terms “health AND economics AND dentistry”. A secondary search was conducted with the terms “heath care AND dentistry AND”. The third part of the entry was changed to address the aims and included the following terms: “cost benefit analysis”, “efficiency criteria”, “supply & demand”, “cost-effectiveness”, “cost minimisation”, “cost utility”, “resource allocation”, “QALY”, and “delivery and economics”. Limits were applied to all searches to only include papers published in English within the last eight years.
Results: Preliminary results demonstrated a limited number of economic evaluations conducted in dentistry. Those that were carried out were mainly confined to the United Kingdom. Furthermore analysis was mainly restricted to restorative dentistry, followed by orthodontics, and maxillofacial surgery, thereby demonstrating a need for investigation in all fields of dentistry.
Conclusion: Health economics has been overlooked in the past regarding delivery of dental care and resource allocation. Economic appraisal is a crucial part of generating an effective and efficient dental care system. It is becoming increasingly evident that there is a need for economic evaluation in all dental fields.

Nutritional Status of older patients attending Cork University Dental School and Hospital

Objectives: This study aimed to gather data on the nutritional status of older patients attending Cork University Dental School and Hospital for treatment in the Restorative Department. Information was also collected about the medical status of the patients including the prevalence of self-reported xerostomia.
Methods: Data was collected by a self-completion questionnaire followed by a brief clinical examination. Nutritional Status was measured using the short version of the Mini Nutritional Assessment (MNA) which recorded patients’ Body Mass Index (BMI). The MNA consists of 6 parameters (including questions relating to patients’ history and anthropometric data) with a maximum total of 14 points. Scores of 12-14 indicate “normal nutritional status” whilst those between 8 and 11 indicate a patient “at risk of malnutrition”. Scores lower than 8 are an indication a patient who is “malnourished”. All patients attending Cork University Dental School and Hospital aged 65 years and older were invited to participate in the study.

Results: A total of 22 subjects participated in this study. Twelve patients were partially dentate with 10 edentulous. The results from the MNA indicate that 11 patients were of “normal nutritional status” with 11 patients identified as being “at risk of malnutrition”. None of the subjects were “malnourished”. Edentate patients generally recorded lower MNA scores than partially dentate patients. In total, 9 patients reported experiencing xerostomia with 8 indicating that they needed to sip liquids to aid swallowing but only 3 had difficulty swallowing food.

Conclusion: This small study indicates that a number of the older patients attending Cork University Dental School and Hospital for dental care may be “at risk of malnutrition”. These findings suggest that nutritional advice and dental care should both be included in an overall package of care for older patients.

Proportioning variability in the dispensation of hand-mixed dental cements

Objectives: The purpose of this investigation was to determine for dispensed multiples (1 through 4) of powder (P) and liquid (L) in hand-mixed dental cement whether: (1) the mean (P/L) ratio (m/m) and (2) the maximum difference in (P/L) ratio is dependent on the number of multiples dispensed. The Null hypotheses were: (a) mean (P/L) ratio is independent of the number of multiples dispensed and (b) maximum difference in (P/L) ratio is independent of the number of multiples dispensed.
Methods: The materials investigated are listed in the Table. The masses of dispensed aliquots of powder and liquid were measured by a single operator (n=10, for multiples 1 through 4) on a 4-place analytical balance. All measurements were made independently and all possible (P/L) ratios calculated for each sample. The effect of multiple dispensations on (P/L) ratios and maximum (P/L) differences was by one-way ANOVA and linear regression, respectively, with the Tukey post-hoc correction for multiple comparisons.MULTIPLE DISPENSEDDISPENSED MU(x1)(x2)(x3)(x4)Zinc phosphateHeraeus12.271(0.691)a13.051(1.269)b13.215(0.824)b13.118(1.149)bFuji IXGC4.209(0.373)a4.085(0.275)b4.095(0.226)b4.095(0.217)bIRMDentsply7.933(0.767)a7.430(0.451)b7.977(0.729)a8.186(0.929)aKetac-Cem3M Espe9.6206(0.613)a9.714(0.523)a9.298(0.314)b9.321(0.292)bMean (SD) powder/liquid ratio (m/m). Superscript letters represent significances (α = 0.05) within each material
Results: Mean (SD) (P/L) ratios are presented in the Table. Null hypothesis (a) is rejected: either (x1) or (x2) dispensation yields a different (P/L) ratio to (x3) or (x4) (p < 0.05). Null hypothesis (b) is rejected: a negative correlation is observed in max (P/L) ratio difference with dispensed multiple for Ketac Cem (p = 0.029).
Conclusion: For hand-mixed dental cements: (1) more consistent (P/L) ratios may be observed with multiple dispensations of powder & liquid; (2) maximum differences in (P/L) ratio may be negatively correlated with dispensation multiple in some materials.