Analytical Approach to the One-Dimensional Disordered Exclusion Process with Open Boundaries and Random Sequential Dynamics

A one dimensional disordered particle hopping rate asymmetric exclusion process (ASEP) with open boundaries and a random sequential dynamics is studied analytically. Combining the exact results of the steady states in the pure case with a perturbative mean field-like approach the broken particle-hole symmetry is highlighted and the phase diagram is studied in the parameter space $(\alpha,\beta)$, where $\alpha$ and $\beta$ represent respectively the injection rate and the extraction rate of particles. The model displays, as in the pure case, high-density, low-density and maximum-current phases. All critical lines are determined analytically showing that the high-density low-density first order phase transition occurs at $\alpha \neq \beta$. We show that the maximum-current phase extends its stability region as the disorder is increased and the usual $1/\sqrt{\ell}$-decay of the density profile in this phase is universal. Assuming that some exact results for the disordered model on a ring hold for a system with open boundaries, we derive some analytical results for platoon phase transition within the low-density phase and we give an analytical expression of its corresponding critical injection rate $\alpha^*$. As it was observed numerically$^{(19)}$, we show that the quenched disorder induces a cusp in the current-density relation at maximum flow in a certain region of parameter space and determine the analytical expression of its slope. The results of numerical simulations we develop agree with the analytical ones.Comment: 23 pages, 7 figures. to appear in J. Stat. Phy

Oral drug dosing following bariatric surgery: general concepts and specific dosing advice

Bariatric or weight-loss surgery is a popular option for weight reduction. Depending on the surgical procedure, gastric changes like decreased transit time and volume and increased pH, decreased absorption surface in the small intestine, decreased exposure to bile acids and enterohepatic circulation, and decreased gastrointestinal transit time may be expected. In the years after bariatric surgery, patients will also substantially lose weight. As a result of these changes, the absorption, distribution, metabolism and/or elimination of drugs may be altered. The purpose of this article is to report the general influence of bariatric surgery on oral drug absorption, and to provide guidance for dosing of commonly used drugs in this special population. Upon oral drug administration, the time to maximum concentration is often earlier and this concentration may be higher with less consistent effects on trough concentrations and exposure. Additionally, prescription of liquid formulations to bariatric patients is supported by some reports, even though the high sugar load of these suspensions may be of concern. Studies on extended-release medications result in an unaltered exposure for a substantial number of drugs. Also, studies evaluating the influence of timing after surgery show dynamic absorption profiles. Although for this group specific advice can be proposed for many drugs, we conclude that there is insufficient evidence for general advice for oral drug therapy after bariatric surgery, implying that a risk assessment on a case-by-case basis is required for each drug.Pharmacolog

The updating of clinical practice guidelines: insights from an international survey

BACKGROUND: Clinical practice guidelines (CPGs) have become increasingly popular, and the methodology to develop guidelines has evolved enormously. However, little attention has been given to the updating process, in contrast to the appraisal of the available literature. We conducted an international survey to identify current practices in CPG updating and explored the need to standardize and improve the methods. METHODS: We developed a questionnaire (28 items) based on a review of the existing literature about guideline updating and expert comments. We carried out the survey between March and July 2009, and it was sent by email to 106 institutions: 69 members of the Guidelines International Network who declared that they developed CPGs; 30 institutions included in the U.S. National Guideline Clearinghouse database that published more than 20 CPGs; and 7 institutions selected by an expert committee. RESULTS: Forty-four institutions answered the questionnaire (42% response rate). In the final analysis, 39 completed questionnaires were included. Thirty-six institutions (92%) reported that they update their guidelines. Thirty-one institutions (86%) have a formal procedure for updating their guidelines, and 19 (53%) have a formal procedure for deciding when a guideline becomes out of date. Institutions describe the process as moderately rigorous (36%) or acknowledge that it could certainly be more rigorous (36%). Twenty-two institutions (61%) alert guideline users on their website when a guideline is older than three to five years or when there is a risk of being outdated. Twenty-five institutions (64%) support the concept of "living guidelines," which are continuously monitored and updated. Eighteen institutions (46%) have plans to design a protocol to improve their guideline-updating process, and 21 (54%) are willing to share resources with other organizations. CONCLUSIONS: Our study is the first to describe the process of updating CPGs among prominent guideline institutions across the world, providing a comprehensive picture of guideline updating. There is an urgent need to develop rigorous international standards for this process and to minimize duplication of effort internationally

Microstructure and Porosity of Laser Welds in Cast Ti-6Al-4V with Addition of Boron

Addition of small amounts of boron to cast Ti-6Al-4V alloy has shown to render a finer microstructure and improved mechanical properties. For such an improved alloy to be widely applicable for large aerospace structural components, successful welding of such castings is essential. In the present work, the microstructure and porosity of laser welds in a standard grade cast Ti-6Al-4V alloy as well as two modified alloy versions with different boron concentrations have been investigated. Prior-β grain reconstruction revealed the prior-β grain structure in the weld zones. In fusion zones of the welds, boron was found to refine the grain size significantly and rendered narrow elongated grains. TiB particles in the prior-β grain boundaries in the cast base material restricted grain growth in the heat-affected zone. The TiB particles that existed in the as cast alloys decreased in size in the fusion zones of welds. The hardness in the weld zones was higher than in the base material and boron did not have a significant effect on hardness of the weld zones. The fusion zones were smaller in the boron-modified alloys as compared with Ti-6Al-4V without boron. Computed tomography X-ray investigations of the laser welds showed that pores in the FZ of the boron modified alloys were confined to the lower part of the welds, suggesting that boron addition influences melt pool flow

[What factors are important for the successful implementation of guidelines?]

Contains fulltext : 69208.pdf (publisher's version ) (Open Access)BACKGROUND: The influence of a guideline on clinical practice depends on the extent to which the recommendations in the guideline are acted upon (degree of adherence). AIM: To assess the degree of adherence to recommendations in evidence-based guidelines and to discuss factors that influence adherence. METHOD: Review of the literature. results In several studies the average degree of adherence to recommendations in guidelines was no higher than 60 to 70%, but the percentage differed markedly, depending on the particular guidelines and the individual professionals involved. The degree of adherence was influenced by a large number of factors; these were connected with the guideline itself, the efforts made by the professional organisations, the organisation of care and institutional management, the individual professional, and the patient. The implementation of a guideline actually begins before and during the formulation of the guideline. Mistakes made in the preparatory phase can have a negative effect on adherence and often it may no longer be possible to correct these mistakes at a later stage. CONCLUSION: If the implementation is to be successful, numerous strategies have to be adopted along the way; for instance, the target-group has to be made aware of the guideline and be encouraged to accept it. Guideline development is not an aim in itself, but should be seen as part of a quality circle in which implementation and evaluation also play an important role

The Netherlands: regulated competition behind the dykes?

Contains fulltext : 81355.pdf (publisher's version ) (Open Access

Clinical guidelines to improve patient care.

Contains fulltext : 48763.pdf (publisher's version ) (Open Access)The aim of clinical guidelines is to improve quality of care by translating new research findings into practice. There is evidence that the following characteristics contribute to their use: inclusion of specific recommendations, sufficient supporting evidence, a clear structure and an attractive lay out. In the process of formulating recommendations, implicit norms of the target users should be taken into account. Guidelines should be developed within a structured and coordinated programme by a credible central organisation. To promote their implementation, guidelines could be used as a template for local protocols, clinical pathways and interprofessional agreements

Quality of clinical practice guidelines

Contains fulltext : 146898.pdf (Publisher’s version ) (Open Access)246 p

Sensitivities: Attention Guiding Dispositions Shaping the Media- and Art Experience

This thesis begins with the observation that there are similarities between audience responses that were recorded after the initial introduction of the moving image and those recorded after the introduction of 3-D cinema. Taking Avatar (2009) as a leading example, this thesis argues that the introduction of 3-D cinema is an instance where medium-sensitivity can be observed. That is, audiences are drawn to Avatar because they want to experience 3-D technology and not because the development of the narrative is highly interesting. Using findings from early cinema studies, cognitive film studies, film aesthetics and philosophy, this thesis will explain what sensitivities are, how they appear and disappear, and what their influence on the reception of cinema is.