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Potential Difficulties (potential + difficulty)
Selected AbstractsMeasuring the effects of indomethacin on changes in cerebral oxidative metabolism and cerebral blood flow during sensorimotor activation,MAGNETIC RESONANCE IN MEDICINE, Issue 1 2003K.S. St. Lawrence The work presented here uses combined blood oxygenation level-dependent (BOLD) and arterial spin tagging (AST) approaches to study the effect of indomethacin on cerebral blood flow (CBF) and oxygen consumption (CMRO2) increases during motor activation. While indomethacin reduced the CBF increase during activation, it did not significantly affect the CMRO2 increase during activation. The ratio of the activation-induced CBF increase in the presence and absence of indomethacin was 0.54 ± 0.08 (±SEM, n = 8, P < 0.001), while the ratio of the CMRO2 increase in the presence and absence of the drug was 1.02 ± 0.08 (±SEM, N = 8, ns). Potential difficulties in estimating CMRO2 changes from combined BOLD/AST data are discussed. Magn Reson Med 50:99,106, 2003. Published 2003 Wiley-Liss, Inc. [source] Procedural learning and dyslexiaDYSLEXIA, Issue 3 2010R. I. Nicolson Abstract Three major ,neural systems', specialized for different types of information processing, are the sensory, declarative, and procedural systems. It has been proposed (Trends Neurosci.,30(4), 135,141) that dyslexia may be attributable to impaired function in the procedural system together with intact declarative function. We provide a brief overview of the increasing evidence relating to the hypothesis, noting that the framework involves two main claims: first that ,neural systems' provides a productive level of description avoiding the underspecificity of cognitive descriptions and the overspecificity of brain structural accounts; and second that a distinctive feature of procedural learning is its extended time course, covering from minutes to months. In this article, we focus on the second claim. Three studies,speeded single word reading, long-term response learning, and overnight skill consolidation,are reviewed which together provide clear evidence of difficulties in procedural learning for individuals with dyslexia, even when the tasks are outside the literacy domain. The educational implications of the results are then discussed, and in particular the potential difficulties that impaired overnight procedural consolidation would entail. It is proposed that response to intervention could be better predicted if diagnostic tests on the different forms of learning were first undertaken. Copyright © 2010 John Wiley & Sons, Ltd. [source] Community psychiatric nurses' experience of working with people who engage in deliberate self-harmINTERNATIONAL JOURNAL OF MENTAL HEALTH NURSING, Issue 3 2008Andrew R. Thompson ABSTRACT:, This paper reports on a study that explored community psychiatric nurses' experiences of working with people who self-harm. Interpretative Phenomenological Analysis was used with eight experienced community psychiatric nurses who participated in semi-structured interviews. Established quality control procedures were utilized including audit of the analysis process and validating the results with participants. The participants described struggling to conceptualize self-harm behaviour and generally reported finding working with people who self-harm stressful particularly in terms of managing the emotional impact upon themselves and the boundaries of their professional responsibilities in relation to managing risk. The therapeutic relationship was viewed as crucial and a variety of coping methods to manage the impact of the work, which had largely developed through ,on the job', experience were described. The results highlight the potential difficulties faced by community staff and can be translated into clear recommendations for training and support. [source] Project 2000: a study of expected and experienced stressors and support reported by students and qualified nursesJOURNAL OF ADVANCED NURSING, Issue 4 2000Hilary Brown MSc BA RNT RN Project 2000: a study of expected and experienced stressors and support reported by students and qualified nurses The present study was conducted in the light of major reforms to nurse education which have taken place in the United Kingdom since 1989. The study aimed to identify initially perceived stressors and coping resources and subsequently, to compare these with actually reported stressors and available resources, during a critical period in nurses' careers. Three groups of nurses participated who were undertaking, or had recently completed, the first Project 2000 course at a university in the south of England. Participants were given an open-ended questionnaire and asked to describe potential difficulties, and the coping resources they anticipated using, in a subsequent 6-month period. Following analysis of the descriptors a structured questionnaire was developed to measure actually experienced difficulties and coping resources that were reported; this was completed by the three groups 6 months after the initial phase of the study. Both student and staff nurse groups reported fewer stressors and more resources than they had predicted. Students anticipated difficulties with competence but actually reported financial difficulties. They experienced support from mentors although this was not anticipated. Newly qualified staff nurses experienced fewer difficulties with meeting personal expectations of the role than they had anticipated. They reported more use of emotion-focused coping and less professional support than the student groups. The results are discussed in relation to training needs. [source] Implantable Cardioverter-Defibrillator Malfunction due to Mechanical Failure of the Header ConnectionJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2004R. ANDREW PICKETT III M.D. Four cases of ICD system malfunction occurring within the Medtronic Marquis family over a limited time frame are reported. These cases shared a common element of defective connections between the header post and the right ventricular pace/sense terminal pin that required intervention and reconnection. Inappropriate shocks occurred in two cases. The circumstances of these cases provide important information about the potential difficulties with these devices and highlight the deficiencies of the current system in tracking and analyzing device-related problems. [source] CAT4 (Cable Actuated Truss,4 Degrees of Freedom): A Novel 4 DOF Cable Actuated Parallel ManipulatorJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 12 2002Craig Kossowski The CAT4 (Cable Actuated Truss,4 degrees of freedom) robot is a novel, passively jointed, parallel robot utilizing six control cables for actuation. The architecture has been under development at the Queen's University Robotics Laboratory. The robot utilizes a passive jointed linkage with 18 revolute joints to constrain the end effector motion and provide the desired structural stability, restricting the end effector to 3 translational degrees of freedom (DOF) and 1 DOF for end effector pitch. This central mechanism together with winched cable actuation gives a number of important benefits for applications where the advantages of a parallel robot are required in conjunction with light weight. Six electric motor driven winches control the length of the cable actuators that extend from the top frame to points on the end effector raft and jointed linkage to create a stiff, but lightweight, actuated robot. Simulation work on the robot is presented giving the kinematics, including a computational estimate of the workspace for a specific configuration. Results of computational simulation of the motion of the manipulator and a discussion of the advantages and potential difficulties are also presented. © 2002 Wiley Periodicals, Inc. [source] Control of a high-purity ethylene glycol reactive distillation column with insights of process dynamicsAICHE JOURNAL, Issue 8 2009Kejin Huang Abstract Inventory control is often regarded as less important than product quality control in the operation of reactive and nonreactive distillation columns (i.e., often detuned considerably in control system design). For the high-purity ethylene glycol reactive distillation column, the inventory control of top condenser is, however, an exception and plays actually a crucial role in the stable and effective process operation, reminding the necessity to thoroughly investigate the intricate dynamic mechanism and its complicated implications on control system synthesis and design. In this article, the dynamics of a high-purity ethylene glycol reactive distillation column is examined, and it is found that the complicated dynamics, for example, the nonminimum phase behavior and process nonlinearity, can be suppressed considerably with the tight inventory control of the top condenser. Moreover, an extremely low controllability is detected, implying the potential difficulties in process operation and thus the need of process design modification. In terms of these insights obtained, two control schemes are devised and studied. It is demonstrated that sharp improvement could be acquired in control system performance when the tight inventory control has been implemented in the top condenser. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Autoimmune thrombocytopenia: flow cytometric determination of platelet-associated autoantibodies against platelet-specific receptorsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2005A. TOMER Summary., Immune thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by antibody-induced platelet destruction. Despite its clinical importance, the diagnosis of ITP is one of exclusion, thus, inevitably associated with potential difficulties. We here describe a feasible diagnostic method using the commonly available technique of flow cytometry. An antigen-specific assay for platelet-associated antibody was developed and tested in 62 adult patients with chronic ITP, 14 patients with thrombocytopenia of decreased production and 60 healthy controls. The method is based on flow cytometric (FCM) detection of autoantibodies reacting with specific platelet receptors immobilized on microbeads. The average fluorescence level in the ITP group calculated as a ratio to normal was 4.07 (range 0.8,31.0), in the non-ITP thrombocytopenic patients 0.9 (range 0.7,1.2), and in the healthy controls 1.0 (range 0.7,1.3). The average assay coefficient of variation was 0.218 [95% confidence interval (CI) 0.213, 0.221]. The difference between the ITP patients and both groups was highly significant (P < 0.001), using a stringent non-parametric analysis. A comparison of the FCM assay with the radioactive immunobead assay previously reported on the same cohort of patients showed significant correlation (R2 = 0.71, 95% CI 0.39, 0.53). The overall performance of the FCM assay in discriminating between ITP patients and normals was estimated by the receiver operating characteristic (ROC) plot, showing an area under the curve of 0.96 (maximal value 1.0), with standard error of 0.033. We conclude that the present FCM assay is clinically useful for routine diagnosis and follow-up of ITP. [source] Multiresistant Pseudomonas aeruginosa in a pediatric cystic fibrosis center: Natural history and implications for segregationPEDIATRIC PULMONOLOGY, Issue 4 2003G. Davies MBChB Abstract It has been suggested that cystic fibrosis (CF) patients harboring multiresistant (MR) Pseudomonas aeruginosa (PA) should be seen in separate clinics. The aim of this study was to test the feasibility of this by longitudinally studying the consistency of isolates of MRPA in individuals. We analyzed all respiratory tract cultures undertaken in 1 year from a pediatric CF clinic population (n,=,367). PA was classified as MR according to the definition of the American CF Foundation: resistance to all agents in at least two of the following groups of antibiotics: ,-lactams, aminoglycosides, and fluroquinolones. PA was cultured from 96 children during the year of study. Thirty-six were infected with at least one MR strain. Following initial identification of MRPA, MR in subsequent cultures was highly variable. Twenty-three of 36 patients had subsequent cultures in which PA was identified. However, 21 of 23 patients had at least one isolate that was not MR following detection of MRPA. The variability with time in isolation of MR strains from individuals demonstrates the potential difficulties in designing segregation policies based on antibiotic sensitivity patterns. Pediatr Pulmonol. 2003; 35:253,256. © 2003 Wiley-Liss, Inc [source] THE CHALLENGE OF ,TECHNOLOGICAL CHOICES'FOR MATERIALS SCIENCE APPROACHES IN ARCHAEOLOGY,ARCHAEOMETRY, Issue 1 2000B. SILLAR Recently several anthropological and sociological studies have interpreted technologies as cultural choices that are determined as much by local perceptions and the social context fly any material constraints or purely functional criteria. Using the example of ceramic technology we consider how materials science studies can contribute to and benefit from this understanding of technology as a social construct. Although we acknowledge some potential difficulties, it is our contention that both materials scientists and archaeologists have gained much and have much to gain by cooperating together to study ancient technologies, and that the concept of ,technological choices'can facilitate a wider consideration of the factors shaping technological developments. [source] Monitoring bird migration with a fixed-beam radar and a thermal-imaging cameraJOURNAL OF FIELD ORNITHOLOGY, Issue 3 2006Sidney A. Gauthreaux Jr ABSTRACT Previous studies using thermal imaging cameras (TI) have used target size as an indicator of target altitude when radar was not available, but this approach may lead to errors if birds that differ greatly in size are actually flying at the same altitude. To overcome this potential difficulty and obtain more accurate measures of the flight altitudes and numbers of individual migrants, we have developed a technique that combines a vertically pointed stationary radar beam and a vertically pointed thermal imaging camera (VERTRAD/TI). The TI provides accurate counts of the birds passing through a fixed, circular sampling area in the TI display, and the radar provides accurate data on their flight altitudes. We analyzed samples of VERTRAD/TI video data collected during nocturnal fall migration in 2000 and 2003 and during the arrival of spring trans-Gulf migration during the daytime in 2003. We used a video peak store (VPS) to make time exposures of target tracks in the video record of the TI and developed criteria to distinguish birds, foraging bats, and insects based on characteristics of the tracks in the VPS images and the altitude of the targets. The TI worked equally well during daytime and nighttime observations and best when skies were clear, because thermal radiance from cloud heat often obscured targets. The VERTRAD/TI system, though costly, is a valuable tool for measuring accurate bird migration traffic rates (the number of birds crossing 1609.34 m [1 statute mile] of front per hour) for different altitudinal strata above 25 m. The technique can be used to estimate the potential risk of migrating birds colliding with man-made obstacles of various heights (e.g., communication and broadcast towers and wind turbines),a subject of increasing importance to conservation biologists. SINOPSIS Estudios previos, en donde no se ha hecho uso de radar, han utilizado cámaras infrarojas de imagen termal (CIT) y el tamaño de individuos como indicador, para detereminar la altura de vuelo. Sin embargo, este método puede dar origen a errores si las aves que vuelan a una misma altura varían en tamaño. Para subsanar esta dificultad y tomar medidas más exactas de la altura de vuelo y el número de individuos en una bandada, desarrollamos una técnica que combina un radar de rayos fijos con antena parabólica (RRF) con una cámara infraroja de imagen termal (RRT/CIT). El CIT provee de un conteo preciso de las aves pasando por un área circular fija de muestreo y el radar provee el dato preciso de la altura de vuelo. Utilizando una videograbadora digital, analizamos las muestras tomadas con la combinación RRT/CIT durante la migración otoñal noctura en el 2000 y el 2003 y durante la migración primaveral diurna del 2003, a través del Golfo de México. Utilizamos la cámara de video para hacer exposiciones en lapsos de tiempo en lo tomado por el CIT y desarrollamos criterios para distinguir entre aves, murciélagos e insectos, usando la huella dejada en el video y la altura del objeto. El CIT trabajo de forma eficiente tanto de dia como de noche, pero aún mejor cuando el cielo estaba despejado (cuando esta ausente la interferencia por la irradiación de calor de parte de las nubes). El sistema RRT/CIT, aunque costoso, es una herramienta valiosa para medir con presición las rutas migratorias y el número de aves moviéndose a diferente altura. Dicho sistema es de gran utilidad para determinar el riesgo de coliciones de aves migratorias con obstáculos construidos por el hombre a diferentes alturas (ej. torres de comunicación o turbinas de viento), asuntos de gran relevancia e importancia para la conservación de aves. [source] The challenge of follow-up in narrowband ultraviolet B phototherapyBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2007B.L. Diffey Summary Background, The use of narrowband ultraviolet (UV) B phototherapy to treat psoriasis and other disorders has increased markedly since the TL-01 lamps were introduced in the 1980s. While broadband UVB phototherapy has generally been considered to be a relatively safe treatment, some concern has been raised about the potential increased skin cancer risk with narrowband UVB. Objectives, The likelihood of a patient who is free of nonmelanoma skin cancer (NMSC) at the start of phototherapy developing a malignancy after a certain follow-up period will be dependent not only on the carcinogenic potential of the treatment but also on the age-conditional probability of natural occurrence. We were interested to explore the potential difficulty of designing studies to separate these two events. Methods, Mathematical models were developed that combined age-conditional probabilities of developing NMSC due to natural causes with the risk of inducing these cancers from narrowband UVB phototherapy in order to estimate the excess number of cancers resulting from this therapeutic intervention in a cohort of patients. Results, Within-department studies will be most unlikely to demonstrate that the number of NMSCs observed in follow-up studies is significantly different from that expected in an untreated population, even for a follow-up period of 20 years. Conclusions, Determination of the carcinogenic potential associated with narrowband UVB will require large multicentre studies typically involving several thousand new patients per year and followed up for 10 years or more. [source] | ||||||||||