2,241 research outputs found

    Permeability evolution across carbonate hosted normal fault zones

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    Acknowledgements: The authors would like to thank Total E&P and BG Group for project funding and support, and the Industry Technology Facilitator for facilitating the collaborative development (grant number 3322PSD). The authors would also like to express their gratitude to the Aberdeen Formation Evaluation Society and the College of Physical Sciences at the University of Aberdeen for partial financial support. Raymi Castilla (Total E&P), Fabrizio Agosta and Cathy Hollis are also thanked for their constructive comments and suggestions to improve the standard of this manuscript as are John Still and Colin Taylor (University of Aberdeen) for technical assistance in the laboratory. Piero Gianolla is thanked for his editorial handling of the manuscript.Peer reviewedPostprin

    Sustained intraatrial reentrant tachycardia: Clinical, electrocardiographic and electrophysiologic characteristics and long-term follow-up

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    Although intraatrial reentry has been traditionally listed as a mechanism for supraventricular tachycardia, few reports describing the clinical features of this arrhythmia exist. Nineteen patients with a clinical history of sustained supraventricular tachycardia were diagnosed as having intraatrial reentrant tachycardia. Seventeen (89%) patients of the 19 had underlying structural heart disease and 17 had echocardiographic evidence of atrial enlargement; the mean left ventricular ejection fraction was 51 Ā± 16%. A history of concomitant atrial fibrillation or flutter was present in 13 patients (68%). The mean atrial cycle length during tachycardia was 326 Ā± 57 ms (range 260 to 460). Fourteen patients had 1:1 atrioventricular (AV) conduction during tachycardia, of whom 50% had an RP7RR' ratio >0.5.Intravenous adenosine (dose range 37.5 to 150 Āµg/kg) and verapamil (dose range 5 to 10 mg) had no effect on atrial tachycardia cycle length in 13 of 14 and 9 of 9 patients, respectively, despite induction of second degree AV block. Type la antiarrhythmic drugs achieved longterm suppression of intraatrial reentrant tachycardia in only 6 patients, whereas amiodarone (326 Ā± 145 mg/day) was successful in 11 patients during a 32 Ā± 20 month follow-up period. The remaining two patients and one patient who later developed amiodarone toxicity either progressed to (n = 1) or had (n = 2) catheter-induced high grade AV block and were treated with long-term ventricular pacing.It is concluded that intraatrial reentrant tachycardia is often associated with structural heart disease, particularly of types that cause atrial abnormalities, but left ventricular dysfunction is not a requisite finding. Other arrhythmias are frequently observed in these patients. This arrhythmia responds poorly to type la antiarrhythmic drugs, but is effectively treated with amiodarone. Catheter ablation of the AV junction offers a therapeutic option for patients who are refractory to medical therapy

    Indirect effects on fitness between individuals that have never met via an extended phenotype

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    Interactions between organisms are ubiquitous and have important consequences for phenotypes and fitness. Individuals can even influence those they never meet, if they have extended phenotypes that alter the environments others experience. North American red squirrels (Tamiasciurus hudsonicus) guard food hoards, an extended phenotype that typically outlives the individual and is usually subsequently acquired by nonā€relatives. Hoarding by previous owners can, therefore, influence subsequent owners. We found that red squirrels breed earlier and had higher lifetime fitness if the previous hoard owner was a male. This was driven by hoarding behaviour, as males and midā€aged squirrels had the largest hoards, and these effects persisted across owners, such that if the previous owner was male or died in midā€age, subsequent occupants had larger hoards. Individuals can, therefore, influence each otherā€™s resourceā€dependent traits and fitness without ever meeting, such that the past can influence contemporary population dynamics through extended phenotypes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148423/1/ele13230.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148423/2/ele13230_am.pd

    Navigating inferior vena cava filters in invasive cardiology procedures: A systematic review

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    BACKGROUND: Transfemoral venous access (TFV) is the cornerstone of minimally invasive cardiac procedures. Although the presence of inferior vena cava filters (IVCFs) was considered a relative contraindication to TFV procedures, small experiences have suggested safety. We conducted a systematic review of the available literature on cardiac procedural success of TFV with IVCF in-situ. METHODS: Two independent reviewers searched PubMed, EMBASE, SCOPUS, and Google Scholar from inception to October 2020 for studies that reported outcomes in patients with IVCFs undergoing TFV for invasive cardiac procedures. We investigated a primary outcome of acute procedural success and reviewed the pooled data for patient demographics, procedural complications, types of IVCF, IVCF dwell time, and procedural specifics. RESULTS: Of the 120 studies initially screened, 8 studies were used in the final analysis with a total of 100 patients who underwent 110 procedures. The most common IVCF was the Greenfield Filter (36%), 60% of patients were males and the mean age was 67.8 years. The overall pooled incidence of acute procedural success was 95.45% (95% confidence interval 89.54. - 98.1) with no heterogeneity (I2 = 0%, p = 1) and there were no reported filter related complications. CONCLUSION: This systematic review is the largest study of its kind to demonstrate the safety and feasibility of TFV access in a variety of cardiac procedures in the presence of IVCF

    Use of a regional wall motion score to enhance risk stratification of patients receiving an implantable cardioverter-defibrillator

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    AbstractObjectives. We postulated that preoperative assessment of both regional wall motion and left ventricular ejection fraction would serve as an accurate prognostic indicator of long-term cardiac mortality and functional outcome in patients treated with an implantable cardioverter-defibrillator.Background. Long-term cardiac mortality has remained high in patients receiving an implantable cardioverter-defibrillator. The ability to risk stratify patients before defibrillator implantation is becoming increasingly important from a medical and economic standpoint.Methods. The hypothesis was retrospectively tested in 74 patients who had received an implantable cardioverterdefibrillator. Left ventricular ejection fraction and regional wall motion score, derived from centerline chord motion analysis, were calculated for each patient from the preoperative right anterior oblique contrast ventriculogram. Wall motion score was the only significant independent predictor of long-term cardiac mortality and functional status by multivariate analysis because of its enhanced prognostic capability in patients with an ejection fraction in the critical range of 30% to 40%.Results. Patients with an ejection fraction >40% had a 3-year cardiac mortality rate of 0% compared with 25% for those with an ejection fraction of 30% to 40% and 48% for those with an ejection fraction <30% (p < 0.05). Similarly, 75% of patients with an ejection fraction >40% were in New York Heart Association functional class I or II during long-term follow-up compared with 59% of those with an ejection fraction 30% to 40% and 29% of those with an ejection fraction <30%. Among patients with an ejection fraction of 30% to 40%, those with a wall motion score >16% had a 3-year cardiac mortality rate of 0% compared with 71% of those with a wall motion score ā‰¤ 16% (p = 0.002). In addition, 86% of patients with a wall motion score >16% were in functional class I or II during long-term follow-up compared with 13% of those with a wall motion score ā‰¤16% (p = 0.001).Conclusions. Long-term cardiac mortality and functional outcome in patients receiving an implantable cardioverterdefibrillator can be predicted if the left ventricular ejection fraction and regional wall motion score are measured preoperatively

    Global health learning outcomes in pharmacy students completing international advanced pharmacy practice experiences

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    Ā© 2020, American Association of Colleges of Pharmacy. All rights reserved. Objective. To examine the global health learning outcomes of Doctor of Pharmacy (PharmD) students from three US schools who participated in international advanced pharmacy practice experiences (APPEs). Methods. A mixed-methods, prospective study was used to assess fourth-year PharmD students at three US pharmacy schools who participated in an international APPE during the 2017-2018 academic year and a matched cohort (control group) of PharmD students who did not participate in an international APPE. To evaluate studentsā€™ self-perceived growth in the Consortium of Universities for Global Health (CUGH) competencies, all students completed a 13-item retrospective pre-post instrument using a five-point Likert scale. The students who had completed an international APPE were invited to participate in a focus group (N522). Paired and independent t tests and multiple linear regression were used to analyze data. Qualitative open-ended questions and focus group data were mapped to knowledge, skills, and attitudes themes. Results. The students who completed an international APPE (N581) showed significantly more growth in CUGH competencies than students who did not (mean improvement in total score of 10.3 [7.0] vs 2.4 [6.0]). International APPE participation was the only significant predictor of growth in CUGH competencies. The international APPE students reported improvements in cultural awareness and appreciation, communication skills, problem-solving skills, adaptability, self-awareness, personal and professional outlook, and global health perspective. Conclusion. Pharmacy studentsā€™ participation in international APPEs led to significant improvement in all CUGH competencies. The CUGH competency framework appears to be a suitable instrument to assess pharmacy studentsā€™ global health learning outcomes

    Upper Kellwasser carbon isotope excursion pre-dates the Fā€“F boundary in the Upper Devonian Lennard shelf carbonate system, Canning Basin, Western Australia

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    Here we report four high-resolution carbon isotope records in addition to trace element data for the Frasnianā€“Famennian (Fā€“F) boundary interval in the Lennard Shelf carbonate system of the Canning Basin, Western Australia. This region lacks the characteristic black shale horizons associated with the global Late Devonian Kellwasser extinction events, yet still exhibits a trend in carbon isotope character similar to what has been reported from elsewhere in the world (two positive Ī“13C excursions with ~3ā€“4ā€° amplitudes). Enrichments in select trace element ratios suggest that both excursions are related to periods of oxygen deprivation and perhaps increased biological productivity. Given the continuous and stratigraphically expanded nature of Lennard Shelf sections, together with high-density sampling constrained by both conodont biostratigraphy and magnetostratigraphy, we observe that the Upper Kellwasser isotope excursion (maximum Ī“13C values) and associated trace element enrichments occur distinctly lower than the Fā€“F boundary level. These results have implications for the paleoenvironmental conditions leading up to the Late Devonian Mass Extinction in terms of ocean chemistry and circulation patterns. This data set allows for a rare, detailed look at the temporal relationship between the Kellwasser events and the Fā€“F boundary and constrains the pattern of carbon isotope perturbations at the intra-zonal scale

    Global health learning outcomes by country location and duration for international experiences

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    Ā© 2020 American Association of Colleges of Pharmacy. Objective. To determine the impact of country income classification and experience duration on learning outcomes for student pharmacists participating in international advanced pharmacy practice experiences (APPEs). Methods. A mixed-methods, longitudinal study evaluated 81 fourth-year student pharmacists participating in an international APPE through one of three US universities. A pre-post survey was administered to evaluate studentsā€™ self-perceived growth across 13 competencies established by the Consortium of Universities for Global Health (CUGH). The survey included four additional open-ended questions. Student pharmacists were also invited to participate in a focus group. Paired and independent t tests and multiple linear regression were conducted. Qualitative survey and focus group data underwent a two-cycle, open-coding process using conventional content analysis. Results. Students who completed their APPE in a low-to middle-income country had greater growth in all CUGH competency statements compared to those who completed their APPE in a high-income country. Completing the APPE in a low-to middle-income country and prior travel for non-vacation purposes were significant predictors of student growth. Students who went to a low-to middle-income country demonstrated increased cultural sensitivity, more patient-centered care, and skill development, while students who went to a high-income country displayed increased knowledge regarding differ-ences in health care system components, pharmacy practice, pharmacy education, and an appreciation for alternative patient care approaches. Conclusion. Learning outcomes differed between students who completed an APPE in a high-income rather than a low-to middle-income country, with both types of locations providing valuable educational opportunities and professional and personal development

    Using elemental chemostratigraphy on Mid-Late Frasnian platform-top successions from the Lennard Shelf outcrops, Canning Basin, Western Australia.

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    High-resolution chronostratigraphic correlation using elemental chemostratigraphy in platform carbonates is typically difficult to achieve. Here, elemental chemostratigraphy is used to correlate between two platform-top, carbonate-dominated field sections from the narrow Lennard Shelf that existed on the NE margin of the Canning Basin, Western Australia, during the midā€“late Frasnian. The correlation, constrained by magnetic polarity reversals and physical ground truthing, is based on recognition of distinctive cyclical ā€˜ā€˜stacking patternsā€™ā€™ defined by changes in concentrations of the trace element zirconium (Zr). Zr concentrations are controlled by the amount of the heavy mineral zircon in the sediments, which is derived from a terrigenous source and is diagenetically very stable. The stacking patterns in the lower part of the study sections display gradually upward-increasing values of Zr to a maximum, followed by an almost immediate fall to a minimum. In the upper part of the study interval, the cycles are more symmetrical, with both gradually increasing and decreasing portions. The point at which the change in Zr stacking pattern occurs in the two sections is synchronous and occurs in association with a supersequence maximum flooding surface. The correlation based on maximum and minimum Zr values throughout the two sections is demonstrated to be chronostratigraphic by comparison with correlations based upon paleomagnetism and physical ground truthing. When element ratios commonly used as provenance and paleoclimate proxies are plotted, the variations between closely spaced samples are greater than any systematic variations throughout the study intervals. Therefore, no isochemical chemozones can be defined, implying that during deposition of the study intervals, there were no long-lived changes in sediment provenance or paleoclimate that the elemental chemistry can detect. The work presented here shows that the standard approach of defining isochemical chemozones for chemostratigraphic correlation is not always appropriate. However, an approach using cyclical changes in elemental variables for chemostratigraphic correlation between two closely spaced sections is chronostratigraphically valid. The greater challenge is in application of the same approach to more widely spaced sections, potentially in different facies of a carbonate setting
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