186 research outputs found

    Non-uniform tropical forest responses to the ‘Columbian Exchange’ in the Neotropics and Asia-Pacific

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    It has been suggested that Iberian arrival in the Americas in 1492 and subsequent dramatic depopulation led to forest regrowth that had global impacts on atmospheric CO2 concentrations and surface temperatures. Despite tropical forests representing the most important terrestrial carbon stock globally, systematic examination of historical afforestation in these habitats in the Neotropics is lacking. Additionally, there has been no assessment of similar depopulation–afforestation dynamics in other parts of the global tropics that were incorporated into the Spanish Empire. Here, we compile and semi-quantitatively analyse pollen records from the regions claimed by the Spanish in the Atlantic and Pacific to provide pan-tropical insights into European colonial impacts on forest dynamics. Our results suggest that periods of afforestation over the past millennium varied across space and time and depended on social, economic and biogeographic contexts. We argue that this reveals the unequal and divergent origins of the Anthropocene as a socio-political and biophysical process, highlighting the need for higher-resolution, targeted analyses to fully elucidate pre-colonial and colonial era human–tropical landscape interactions.Results - Neotropics. - Spanish East Indies. Discussion Methods - Neotropics data preparation. - Spanish East Indies data preparation. - Generalized additive modelling of palaeoecological data. - Analysis of afforestation signal over 2,000 years. - Reporting Summary

    Collagen fingerprinting traces the introduction of caprines to island Eastern Africa

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    The human colonization of eastern Africa's near- and offshore islands was accompanied by the translocation of several domestic, wild and commensal fauna, many of which had long-term impacts on local environments. To better understand the timing and nature of the introduction of domesticated caprines (sheep and goat) to these islands, this study applied collagen peptide fingerprinting (Zooarchaeology by Mass Spectrometry or ZooMS) to archaeological remains from eight Iron Age sites, dating between ca 300 and 1000 CE, in the Zanzibar, Mafia and Comoros archipelagos. Where previous zooarchaeological analyses had identified caprine remains at four of these sites, this study identified goat at seven sites and sheep at three, demonstrating that caprines were more widespread than previously known. The ZooMS results support an introduction of goats to island eastern Africa from at least the seventh century CE, while sheep in our sample arrived one–two centuries later. Goats may have been preferred because, as browsers, they were better adapted to the islands' environments. The results allow for a more accurate understanding of early caprine husbandry in the study region and provide a critical archaeological baseline for examining the potential long-term impacts of translocated fauna on island ecologies.1. Introduction 2. Background 2.1. Island colonization and species translocations 2.2. Tracing the introduction of caprines to insular Eastern Africa 3. Methods 3.1. Sites 3.2. Sample selection 3.3. ZooMS protocol 3.3.1. Acid-insoluble protocol 3.3.2. Acid-soluble protocol 3.3.3. Lyophilized collagen for stable isotope analysis 3.3.4. C18 clean-up and MALDI-ToF analysis 4. Results 5. Discussion 5.1. Diachronic patterns in the introduction of caprines 5.2. Island herd compositions 5.3. Wild faunal extirpations and translocations 5.4. Long-term ecological impacts of caprines on Eastern Africa’s islands 6. Conclusio

    Cognitive apprenticeship in clinical practice: can it stimulate learning in the opinion of students?

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    Learning in clinical practice can be characterised as situated learning because students learn by performing tasks and solving problems in an environment that reflects the multiple ways in which their knowledge will be put to use in their future professional practice. Collins et al. introduced cognitive apprenticeship as an instructional model for situated learning comprising six teaching methods to support learning: modelling, coaching, scaffolding, articulation, reflection and exploration. Another factor that is looked upon as conducive to learning in clinical practice is a positive learning climate. We explored students’ experiences regarding the learning climate and whether the cognitive apprenticeship model fits students’ experiences during clinical training. In focus group interviews, three groups of 6th-year medical students (N = 21) discussed vignettes representing the six teaching methods and the learning climate to explore the perceived occurrence of the teaching methods, related problems and possibilities for improvement. The students had experienced all six teaching methods during their clerkships. Modelling, coaching, and articulation were predominant, while scaffolding, reflection, and exploration were mainly experienced during longer clerkships and with one clinical teacher. The main problem was variability in usage of the methods, which was attributed to teachers’ lack of time and formal training. The students proposed several ways to improve the application of the teaching methods. The results suggest that the cognitive apprenticeship model is a useful model for teaching strategies in undergraduate clinical training and a valuable basis for evaluation, feedback, self-assessment and faculty development of clinical teachers

    Outcomes After Major Surgical Procedures in Octogenarians:A Nationwide Cohort Study

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    Introduction: Aging of the worldwide population has been observed, and postoperative outcomes could be worse in elderly patients. This nationwide study assessed trends in number of surgical resections in octogenarians regarding various major surgical procedures and associated postoperative outcomes. Methods: All patients who underwent surgery between 2014 and 2018 were included from Dutch nationwide quality registries regarding esophageal, stomach, pancreas, colorectal liver metastases, colorectal cancer, lung cancer and abdominal aortic aneurysms (AAA). For each quality registry, the number of patients who were 80 years or older (octogenarians) was calculated per year. Postoperative outcomes were length of stay (LOS), 30 day major morbidity and 30 day mortality between octogenarians and younger patients. Results: No increase in absolute number and proportion of octogenarians that underwent surgery was observed. Median LOS was higher in octogenarians who underwent surgery for colorectal cancer, colorectal liver metastases, lung cancer, pancreatic disease and esophageal cancer. 30 day major morbidity was higher in octogenarians who underwent surgery for colon cancer, esophageal cancer and elective AAA-repair. 30 day mortality was higher in octogenarians who underwent surgery for colorectal cancer, lung cancer, stomach cancer, pancreatic disease, esophageal cancer and elective AAA-repair. Median LOS decreased between 2014 and 2018 in octogenarians who underwent surgery for stomach cancer and colorectal cancer. 30 day major morbidity decreased between 2014 and 2018 in octogenarians who underwent surgery for colon cancer. No trends were observed in octogenarians regarding 30 day mortality between 2014 and 2018. Conclusion: No increase over time in absolute number and proportion of octogenarians that underwent major surgery was observed in the Netherlands. Postoperative outcomes were worse in octogenarians

    Combined student ratings and self-assessment provide useful feedback for clinical teachers

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    Many evaluation instruments have been developed to provide feedback to physicians on their clinical teaching but written feedback alone is not always effective. We explored whether feedback effectiveness improved when teachers’ self-assessment was added to written feedback based on student ratings. 37 physicians (10 residents, 27 attending physicians) from different specialties (Internal Medicine, Surgery, Obstetrics/Gynecology, Pediatrics, Neurology, Dermatology, Ophthalmology, ENT, and Psychiatry) were invited to fill out a self-assessment questionnaire on their teaching skills. Students completed an almost identical questionnaire to evaluate the same teachers based on their experiences during clerkships. After receiving written feedback incorporating their self-assessment and the student ratings, the teachers indicated their perceptions of the self-assessment exercise and the written feedback in a questionnaire (five-point Likert scale items) and next, in more detail, in semi-structured interviews with a purposive sample of 12 of the participating teachers. 25 physicians participated (67%). The results showed that self-assessment and student feedback were both perceived as useful (3.7, SD 1.0) but the latter was considered more effective. The physicians we interviewed considered the combination of self-assessment with student ratings more effective than either self-assessment or written feedback alone. Notably, discrepancies between student ratings and self-assessment were deemed a strong incentive for change. We conclude that self-assessment can be a useful tool to stimulate improvement of clinical teaching when it is combined with written feedback based on student ratings. Future research among larger groups is needed to confirm our findings and examine whether these combined tools actually lead to improved teaching

    Does electronic clinical microbiology results reporting influence medical decision making: a pre- and post-interview study of medical specialists

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    Background: Clinicians view the accuracy of test results and the turnaround time as the two most important service aspects of the clinical microbiology laboratory. Because of the time needed for the culturing of infectious agents, final hardcopy culture results will often be available too late to have a significant impact on early antimicrobial therapy decisions, vital in infectious disease management. The clinical microbiologist therefore reports to the clinician clinically relevant preliminary results at any moment during the diagnostic process, mostly by telephone. Telephone reporting is error prone, however. Electronic reporting of culture results instead of reporting on paper may shorten the turnaround time and may ensure correct communication of results. The purpose of this study was to assess the impact of the implementation of electronic reporting of final microbiology results on medical decision making. Methods. In a pre- and post-interview study using a semi-structured design we asked medical specialists in our hospital about their use and appreciation of clinical microbiology results reporting before and after the implementation of an electronic reporting system. Results: Electronic reporting was highly appreciated by all interviewed clinicians. Major advantages were reduction of hardcopy handling and the possibility to review results in relation to other patient data. Use and meaning of microbiology reports differ significantly between medical specialties. Most clinicians need preliminary results for therapy decisions quickly. Therefore, after the implementation of electronic reporting, telephone consultation between clinician and microbiologist remained the key means of communication. Conclusions: Overall, electronic reporting increased the workflow efficiency of the medical specialists, but did not have an impact on their decision-making

    Healthcare-associated prosthetic heart valve, aortic vascular graft, and disseminated Mycobacterium chimaera infections subsequent to open heart surgery

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    Aims We identified 10 patients with disseminated Mycobacterium chimaera infections subsequent to open-heart surgery at three European Hospitals. Infections originated from the heater-cooler unit of the heart-lung machine. Here we describe clinical aspects and treatment course of this novel clinical entity. Methods and results Interdisciplinary care and follow-up of all patients was documented by the study team. Patients' characteristics, clinical manifestations, microbiological findings, and therapeutic measures including surgical reinterventions were reviewed and treatment outcomes are described. The 10 patients comprise a 1-year-old child and nine adults with a median age of 61 years (range 36-76 years). The median duration from cardiac surgery to diagnosis was 21 (range 5-40) months. All patients had prosthetic material-associated infections with either prosthetic valve endocarditis, aortic graft infection, myocarditis, or infection of the prosthetic material following banding of the pulmonary artery. Extracardiac manifestations preceded cardiovascular disease in some cases. Despite targeted antimicrobial therapy, M. chimaera infection required cardiosurgical reinterventions in eight patients. Six out of 10 patients experienced breakthrough infections, of which four were fatal. Three patients are in a post-treatment monitoring period. Conclusion Healthcare-associated infections due to M. chimaera occurred in patients subsequent to cardiac surgery with extracorporeal circulation and implantation of prosthetic material. Infections became clinically apparent after a time lag of months to years. Mycobacterium chimaera infections are easily missed by routine bacterial diagnostics and outcome is poor despite long-term antimycobacterial therapy, probably because biofilm formation hinders eradication of pathogen

    Evaluation of the Antiviral Response to Zanamivir Administered Intravenously for Treatment of Critically Ill Patients With Pandemic Influenza A (H1N1) Infection

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    A retrospective nationwide study on the use of intravenous (IV) zanamivir in patients receiving intensive care who were pretreated with oseltamivir in the Netherlands was performed. In 6 of 13 patients with a sustained reduction of the viral load, the median time to start IV zanamivir was 9 days (range, 4–11 days) compared with 14 days (range, 6–21 days) in 7 patients without viral load reduction (P = .052). Viral load response did not influence mortality. We conclude that IV zanamivir as late add-on therapy has limited effectiveness. The effect of an immediate start with IV zanamivir monotherapy or in combination with other drugs need to be evaluated

    Ready or not? Expectations of faculty and medical students for clinical skills preparation for clerkships

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    Background: Preclerkship clinical-skills training has received increasing attention as a foundational preparation for clerkships. Expectations among medical students and faculty regarding the clinical skills and level of skill mastery needed for starting clerkships are unknown. Medical students, faculty teaching in the preclinical setting, and clinical clerkship faculty may have differing expectations of students entering clerkships. If students' expectations differ from faculty expectations, students may experience anxiety. Alternately, congruent expectations among students and faculty may facilitate integrated and seamless student transitions to clerkships. Aims: To assess the congruence of expectations among preclerkship faculty, clerkship faculty, and medical students for the clinical skills and appropriate level of clinical-skills preparation needed to begin clerkships. Methods: Investigators surveyed preclinical faculty, clerkship faculty, and medical students early in their basic clerkships at a North American medical school that focuses on preclerkship clinical-skills development. Survey questions assessed expectations for the appropriate level of preparation in basic and advanced clinical skills for students entering clerkships. Results: Preclinical faculty and students had higher expectations than clerkship faculty for degree of preparation in most basic skills. Students had higher expectations than both faculty groups for advanced skills preparation. Conclusions: Preclinical faculty, clerkship faculty, and medical students appear to have different expectations of clinical-skills training needed for clerkships. As American medical schools increasingly introduce clinical-skills training prior to clerkships, more attention to alignment, communication, and integration between preclinical and clerkship faculty will be important to establish common curricular agendas and increase integration of student learning. Clarification of skills expectations may also alleviate student anxiety about clerkships and enhance their learning
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