k-t BLAST and SENSE accelerated time-resolved three-dimensional phase contrast MRI in an intracranial aneurysm

Objective

The objective of this study was to investigate the performance of k-t BLAST (Broad-use Linear Acquisition Speed-up Technique) accelerated time-resolved 3D PC-MRI compared to SENSE (SENSitivity Encoding) acceleration in an in vitro and in vivo intracranial aneurysm.

Materials and methods

Non-accelerated, SENSE and k-t BLAST accelerated time-resolved 3D PC-MRI measurements were performed in vivo and in vitro. We analysed the consequences of various temporal resolutions in vitro.

Results

Both in vitro and in vivo measurements showed that the main effect of k-t BLAST was underestimation of velocity during systole. In the phantom, temporal blurring decreased with increasing temporal resolution. Quantification of the differences between the non-accelerated and accelerated measurements confirmed that in systole SENSE performed better than k-t BLAST in terms of mean velocity magnitude. In both in vitro and in vivo measurements, k-t BLAST had higher SNR compared to SENSE. Qualitative comparison between measurements showed good similarity.

Conclusion

Comparison with SENSE revealed temporal blurring effects in k-t BLAST accelerated measurements.     

Evidence-based management: using serial firm trials to improve diabetes care quality

BACKGROUND: The design of delivery systems that can truly conduct continuous quality improvement (CQI) as a routine part of clinical care provision remains a vexing problem. The effectiveness of the "computerized firm system" approach to chronic disease CQI was examined, with diabetes as the focus of a 5-year case study. METHODS: A large family medical center had been divided into two parallel group practices for reasons of efficiency. These frontline structures (also known as primary care "firms") were supported to serially adapt and evaluate selected CQI interventions by first introducing process changes on one firm but not the other and comparing the groups. Because all the required longitudinal data were contained in a computerized repository, it was possible to conduct these controlled "firm trials" in a matter of months at low cost. RESULTS: During a 3-year period, implementation of point-of-service reminders and a pharmacist out-reach program increased recommended glycohemoglobin (HbA1c) testing by 50% (p = 0.02) and reduced the number of diabetic patients inadequately controlled by 43% (p < 0.01). Following this outcome improvement, patients exhibited a 16% reduction in ambulatory visit rates (p = 0.04). The observed outcome improvement, however, was reversed during the subsequent 2 years, when staffing austerities forced by unrelated declines in clinic revenue caused the withdrawal of trial interventions. CONCLUSIONS: The processes and outcomes of diabetes care were improved, demonstrating that CQI and controlled trials are not mutually exclusive in moving toward the practice of evidence-based management. Health care systems can, by conducting serial firm trials, become learning organizations. CQI programs of all kinds will likely never flourish, however, until quality improvement and reimbursement mechanisms have become better aligned.     

A Methodology for Architecture Exploration of Heterogeneous Signal Processing Systems

We present a methodology for the exploration of signal processing architectures at the system level. The methodology, named SPADE, provides a means to quickly build models of architectures at an abstract level, to easily map applications, modeled as Kahn Process Networks, onto these architecture models, and to analyze the performance of the resulting system by simulation. The methodology distinguishes between applications and architectures, and uses a trace-driven simulation technique for co-simulation of application models and architecture models. As a consequence, architecture models need not be functionally complete to be used for performance analysis while data dependent behavior is still handled correctly. We have used the methodology for the exploration of architectures and mappings of an MPEG-2 video decoder application.     

Rumination and overgeneral memory in depression: Effects of self-focus and analytic thinking.

Previous research has shown that, compared with a rumination induction, a brief distraction procedure reduces overgeneral autobiographical memory in depression. The authors investigated whether this effect depends on reductions in analytic thinking or reductions in self-focus. Focus of attention (high vs. low self-focus) and thinking style (high vs. low analytical thinking) were independently manipulated in depressed patients in a 2 X 2 design. Autobiographical recall was measured pre- and postmanipulation. Thinking style significantly affected overgeneral memory, whereas focus of attention significantly affected despondent mood. Reducing analytical self-focus reduced overgeneral memory, suggesting that high levels of naturally occurring ruminative analytic thinking may be important in the maintenance of overgeneral memory. Overgeneral memory in depression may be associated with chronic ruminative attempts to make sense of current or past difficulties. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Professional Program Criteria for Civil Engineering Curriculums

The Accreditation Board for Engineering and Technology (ABET) has adopted a revised set of accreditation criteria that is designed to ensure that graduates of accredited programs are prepared to enter the practice of engineering. The proposal also specifies that engineering programs must demonstrate that their graduates have an understanding of professional practice issues in addition to proficiency in specific subject areas that are tabulated in the civil engineering program criteria. The findings of this study indicate that engineering undergraduate and graduate students as well as practitioners perceive that four subject areas are of great importance for civil engineers. They include structural engineering, hydraulics∕hydrology∕water resources, engineering design, and mathematics through calculus and differential equations. In contrast, one area, chemistry, received lower ratings. The data suggest that the majority of subjects included in the civil engineering program criteria are considered by students and practitioners to have generally the same level of importance and should be included in the curriculum at an above average level. In particular, 81% of the subject areas included in the ABET civil engineering program criteria are rated by both students and practitioners with a composite score ≥3.1. This may be interpreted as strong support for the Engineering Criteria 2000 program requirements.     

Citation delay in interdisciplinary knowledge exchange

As part of a larger project to investigate knowledge flows between fields of science, westudied the differences in speed of knowledge transfer within and across disciplines. The agedistribution of references in three selections of articles was analysed, including almost 800.000references in journal publications of the United Kingdom in 1992, 700.000 references inpublications of Germany in 1992, and more than 11 million references in the world total ofpublications in 1998.The rate of citing documented knowledge from other disciplines appears to differ sharplyamong disciplines. For most of the disciplines the same ratio's are found in the three data sets.Exceptions show interesting differences in the interdisciplinary nature of a field in a country. Wefind a general tendency of a citation delay in case of knowledge transfer between different fieldsof science: citations to work of the own discipline show less of a time lag than citations to work ina foreign discipline. Between disciplines typical differences in the speed of incorporatingknowledge from other disciplines are observed, which appear to be relatively independent of timeand place: for each discipline the same pattern is found in the three data sets. The disciplinespecific characteristics found in the speed of interdisciplinary knowledge transfer may be point ofdeparture for further investigations. Results may contribute to explanations of differences incitation rates of interdisciplinary research.     

Isomers of dechlorane plus in Lake Winnipeg and Lake Ontario food webs

The extent of bioaccumulation of the syn- and anti-isomers of Dechlorane Plus (DP) is assessed in archived food web samples from Lake Winnipeg and Lake Ontario. Concentrations of the isomers were determined using purified analytical solutions of individual isomers as opposed to the technical mixture. The syn-isomer was consistently detected in all samples from both lakes; the anti-isomer was detected in all Lake Ontario samples, but only 45% of the samples from Lake Winnipeg. The pattern of bioaccumulation was different for the isomers in Lake Winnipeg. The anti-isomer was dominant in higher trophic level (TL) organisms like walleye [arithmetic mean +/- 1 x standard error: 730 +/- 120 pg/g, lipid weight (1w)] and goldeye (760 +/- 170 pg/g, Iw) while the syn-isomer dominated the lower TL organisms like zooplankton (550 +/- 40 pg/g, Iw) and mussels (430 +/- 140 pg/g, Iw). In Lake Ontario, the extent of bioaccumulation of the isomers and concentrations was greatest in the lower TL benthic organism, Diporeia (syn, 1307 +/- 554; and anti, 3108 +/- 898 pg/g Iw) and also high in zooplankton (syn, 719; and anti, 1332 pg/g Iw). This suggests that the isomers are bioavailable in sediment and that, despite their molecular size, diffusion from the water column into zooplankton can occur. Differences in the mean fractional abundance of the anti-isomer (mean fanti = mean concentration of the anti-isomer divided by sum of mean syn- and anti-concentrations) were pronounced in sediments between lakes (Lake Winnipeg mean fanti = 0.610, Lake Ontario mean fanti = 0.860) and the extent of enrichment (anti-) and depletion (syn-) of the isomers were more marked in Lake Winnipeg biota. There were also differences in the biomagnification potentials, as measured bythe trophic magnification factor (TMF), between the isomers in the Lake Winnipeg food web; no statistically significant TMFs for either isomer were found for the     

Concreteness training reduces dysphoria: Proof-of-principle for repeated cognitive bias modification in depression.

A tendency toward abstract and overgeneral processing is a cognitive bias hypothesized to causally contribute to symptoms of depression. This hypothesis predicts that training dysphoric individuals to become more concrete and specific in their thinking would reduce depressive symptoms. To test this prediction, 60 participants with dysphoria were randomly allocated either to (a) concreteness training; (b) bogus concreteness training, matched with concreteness training for treatment rationale, experimenter contact, and treatment duration but without active engagement in concrete thinking; (c) a waiting-list, no training control. Concreteness training resulted in significantly greater decreases in depressive symptoms and significantly greater increases in concrete thinking than the waiting-list and the bogus training control, and significantly greater decreases in rumination than the waiting-list control. These findings suggest that concreteness training has potential as a guided self-help intervention for mild-to-moderate depressive symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)