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Challenging Aspect (challenging + aspect)
Selected AbstractsParallel computation of a highly nonlinear Boussinesq equation model through domain decompositionINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 1 2005Khairil Irfan Sitanggang Abstract Implementations of the Boussinesq wave model to calculate free surface wave evolution in large basins are, in general, computationally very expensive, requiring huge amounts of CPU time and memory. For large scale problems, it is either not affordable or practical to run on a single PC. To facilitate such extensive computations, a parallel Boussinesq wave model is developed using the domain decomposition technique in conjunction with the message passing interface (MPI). The published and well-tested numerical scheme used by the serial model, a high-order finite difference method, is identical to that employed in the parallel model. Parallelization of the tridiagonal matrix systems included in the serial scheme is the most challenging aspect of the work, and is accomplished using a parallel matrix solver combined with an efficient data transfer scheme. Numerical tests on a distributed-memory super-computer show that the performance of the current parallel model in simulating wave evolution is very satisfactory. A linear speedup is gained as the number of processors increases. These tests showed that the CPU time efficiency of the model is about 75,90%. Copyright © 2005 John Wiley & Sons, Ltd. [source] Delivery of endostatin in experimental cancer therapyINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 6 2002Dag R. Sorensen Summary. Endostatin, the 20 kDa C-terminal fragment of collagen XVIII, has been shown to be an effective inhibitor of tumour angiogenesis and growth in different experimental systems and is currently in Phase II/III clinical trials. One challenging aspect of anti-angiogenic treatment is the mode of delivery of the active compound. In this paper we review some of the basic knowledge of endostatin and look specifically into the different possible ways in which endostatin may be administered. [source] Relay communications for Mars explorationINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 2 2007Charles D. Edwards Telecommunication is an essential and challenging aspect of planetary exploration. For Mars landers, the constraints of mass, volume, power and energy typically limit their communications capabilities on the long-distance link back to Earth. By deploying relay spacecraft in Martian orbit, these landers can achieve much greater data return and can obtain contact opportunities at times when Earth is not in view. Currently, both NASA and European Space Agency (ESA) have pursued this strategy, deploying relay payloads on their Mars science orbiters. This relay infrastructure has significantly benefited the science return from the 2003 Mars Exploration Rovers and is poised to support the Phoenix Lander and Mars Science Laboratory missions later this decade. Longer-term plans call for continued growth in relay capability, greatly increasing data return from the Martian surface to enable exciting new Mars exploration concepts and advance our understanding of our planetary neighbour. Copyright © 2007 John Wiley & Sons, Ltd. [source] The challenges for nurses communicating with and gaining valid consent from adults with intellectual disabilities within the accident and emergency care serviceJOURNAL OF CLINICAL NURSING, Issue 9 2007Margaret Sowney MSc Aim., This paper reports the challenges experienced by nurses within accident and emergency departments in communicating with and gaining valid consent from adults with intellectual disabilities. Background., Consent is both a legal requirement and an ethical principle required to be obtained by health-care professionals, prior to the start of any examination, treatment and/or care. Central to the process of seeking consent is effective communication. However, evidence shows that people with intellectual disabilities are not viewed by professionals within acute general hospitals as a vital source of information, neither are they often communicated with directly, nor involved in discussions or decisions about their health care and are frequently not directly asked for their consent. Method., A purposive sample of nurses working within the accident and emergency departments of five general hospitals was recruited to participate in this qualitative study. Data were collected from five focus groups. Findings., Effective communication was identified as the most challenging aspect in caring for adults with intellectual disabilities within this environment, having an impact on the assessment of needs, informing patients of their health status and seeking valid consent. Conclusions., Fundamental to the provision of quality care are the concepts communication, choice and control. However, these issues are perceived to be more challenging in the provision of health care to people with intellectual disabilities. Communication and consent, therefore, require further consideration within the educational and clinical areas to strengthen nurses' competence in caring for people with intellectual disabilities, with an emphasis and understanding that choice and control are key principles for all people, being central aspects to the provision of an inclusive service for people with intellectual disabilities. Relevance to clinical practice., All nurses need to have a greater awareness of learning disability, how to increase opportunities for effective communication and be very familiar with the issue and guidelines relating to consent, to ensure that people with learning disabilities have choice, control and are more active in decision making regarding their health. [source] Phosphodiesterase 5 (PDE 5) inhibitors for the treatment of male erectile disorder: Attaining selectivity versus PDE6MEDICINAL RESEARCH REVIEWS, Issue 3 2006Dmitri Pissarnitski Abstract The role of phosphodiesterase type 5 (PDE5) in the mechanism of male erection has been well understood, and several drugs inhibiting this enzyme are being used for the treatment of erectile dysfunction (ED). Discovery of inhibitors with improved selectivity versus other PDE isozymes could lead to drugs with improved safety profile. Achievement of selectivity versus PDE6, co-inhibition of which results in disturbances of color perception, remains the most challenging aspect of current drug discovery programs. The present review describes several case studies, where significant (>100 fold) selectivity versus PDE6 has been attained via investigation of structure,activity relationships (SAR). Special attention is given to the chemical routes leading to novel chemotypes and allowing efficient exploration of their SAR's. Strategies for attaining inhibitor selectivity discussed below may be applicable for other drug discovery programs. © 2005 Wiley Periodicals, Inc. Med Res Rev [source] Neural mechanisms of cutaneous nociceptive pain. (Department of Neurology, University of Würzburg, Germany) Clin J Pain 2000;16:S131,S138.PAIN PRACTICE, Issue 2 2001Martin Koltzenburg: Acute mechanical, thermal, and chemically induced pains in the skin are signaled by a set of specific nociceptive afferents, which encode the magnitude of the perceived pain by their discharge intensity. After tissue injury or inflammation, a number of changes in their properties of the primary afferent occur parallel to profound changes in the central nervous system. Primary hyperalgesia (within the area of tissue injury) is best explained by changes of the properties of primary nociceptive afferents, whereas secondary hyperalgesia (increased pain sensitivity outside the area of tissue injury) critically requires functional changes in the central nervous system. Collectively, these changes are the basis for many forms of hyperalgesia that can present clinically as incident pain. Knowledge of the various types of hyperalgesia and their underlying mechanisms is required for better treatment of this challenging aspect of chronic pain. [source] Promoting evidence-based psychosocial care for cancer patients,PSYCHO-ONCOLOGY, Issue 1 2009Paul B. Jacobsen Abstract With numerous studies demonstrating that psychosocial care reduces distress and improves quality of life, practitioners have an obligation to treat cancer patients in a manner consistent with this evidence. Although the rationale is straightforward, major challenges exist in achieving the goal of translating research into clinical practice. One challenge has been the nature of the evidence, with many studies of psychosocial interventions characterized by poor methodological quality, absence of eligibility criteria specifying heightened distress, and minimal consideration of dissemination potential. A second challenge has been to make practitioners aware of relevant evidence. Targeted efforts at dissemination, such as the issuance of clinical practice guidelines and evidence-based recommendations and the distribution of intervention materials via the Internet, appear to be more effective than passive efforts in providing practitioners with useful information. Perhaps the most challenging aspect has been to persuade practitioners to change how they practice. One approach currently under development would allow practitioners and health-care organizations to perform self-evaluations of the quality of their psychosocial care based on review of medical records. Feedback showing quality of care to be less than optimal is likely to motivate change, especially if the quality indicators assessed are considered to be important and reliable and point to specific actions that can be taken. The use of evidence to promote changes in clinical practice represents one of the major ways in which the field of psycho-oncology can fully realize its potential to positively affect the lives of people with cancer. Copyright © 2008 John Wiley & Sons, Ltd. [source] Pointing control design for a high precision flight telescope using quantitative feedback theoryINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 10 2001Anthony E. Bentley Abstract A pointing control system is developed and tested for a flying gimbaled telescope. The two-axis pointing system is capable of sub-microradian pointing stability and high accuracy in the presence of large host vehicle jitter. The telescope also has high agility , it is capable of a 50° retarget (in both axes simultaneously) in less than 2 s. To achieve the design specifications, high-accuracy, high-resolution, two-speed resolvers were used, resulting in gimbal-angle measurements stable to 1.5 µrad. In addition, on-axis inertial angle displacement sensors were mounted on the telescope to provide host-vehicle jitter cancellation. The inertial angle sensors are accurate to about 100 nrad, but do not measure low-frequency displacements below 2 Hz. The gimbal command signal includes host-vehicle attitude information, which is band-limited. This provides jitter data below 20 Hz, but includes a variable latency between 15 and 25 ms. One of the most challenging aspects of this design was to combine the inertial-angle-sensor data with the less perfect information in the command signal to achieve maximum jitter reduction. The optimum blending of these two signals, along with the feedback compensation were designed using Quantitative Feedback Theory. Copyright © 2001 John Wiley & Sons, Ltd. [source] Designing for Disassembly (DfD)ARCHITECTURAL DESIGN, Issue 6 2009Elma Durmisevic Abstract The redundancy of existing buildings that leads to demolition and the unnecessary disposal of structures and their parts is one of the most challenging aspects of the current construction industry. This large-scale problem of obsolescence leads to the squandering of existing materials and resources on a massive scale. Here Elma Durmisevic and Ken Yeang advocate a means by which disassembly can be designed into buildings from the outset. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||