1. Large variation in tree root architecture and morphology has been reported for temperate forest communities. However, it is not clear whether this variation represents adaptation of species to ...specific soil properties, alternative resource acquisition strategies among co-occurring species, or canalized traits without a strong impact on the success of individuals in different environments. Here, our goal was to test these alternative hypotheses and quantify how community-aggregated and intraspecific root trait variations are explained by biotic versus abiotic mechanisms in a temperate deciduous forest. 2. We conducted our study in an Acer-Fagus-dominated forest in north-east Ohio, USA. Using molecular barcoding techniques, we identified 738 root systems belonging to 14 tree species. We measured seven functional root traits related to root architecture and morphology at the species and community-aggregated levels. 3. Although we found significant relationships between soil resource gradients and root trait distributions, intrinsic differences between coexisting species were more important than soil factors in explaining the distribution of root traits in the community. Additionally, root trait variation at the species level was also influenced by the presence of other species within cores. 4. Community-aggregated variation was more influenced by the combination of species present than soil properties in each sample, suggesting that biotic interactions play an important role in controlling community root trait distribution. 5. Synthesis. We propose that root trait differentiation between coexisting species is the result of inherent differences between species and plasticity-mediated responses to neighbours. Hence, the large variation in root traits reported in temperate forest seems to reflect alternative evolutionary pathways that allow individuals to exploit distinct niches in relatively close proximity.
Residency program prestige is an important variable medical students consider when creating their rank list. Doximity Residency Navigator is a ranking system that previous reports have shown ...significantly influences medical student application decisions. Doximity's use of peer nomination as a central component of its methodology for determining program rank has drawn criticism for its lack of objectivity. Doximity has not published information regarding how peer nomination and more objective measures are statistically weighted in reputation calculation.
This study assesses whether a strong negative correlation exists between residency program size and Doximity ranking.
A cross-sectional study of Doximity residency rankings from the 2018-2019 academic year was conducted. Data extracted from Doximity included program rank, size, and age. Data were additionally collected from the Blue Ridge Institute for Medical Research, National Institutes of Health, funding in 2018 and the
Best Medical Schools 2019-2020. A multivariable linear regression model was used that included Doximity ranking as the outcome variable and residency program size as the predictor variable with adjustment for the aforementioned variables.
Sixteen of the 28 specialties on Doximity were included in the analysis, representing 3388 unique residency programs. After adjustment for covariates, residency program size was a significant predictor of Doximity ranking (β = -1.84; 95% CI -2.01 to -1.66,
< .001).
These findings support the critique that the Doximity reputation ranking system may favor larger residency programs. More transparency for Doximity reputation ranking algorithm is warranted.
Assembly of fungal communities remains poorly understood in part because of the daunting range of spatial scales that may be involved in this process. Here, we use individual leaves as a natural ...sampling unit, comprising spatially distinct habitat and/or resource patches with unique histories and suites of resources. Spatial patterns in fungal beta diversity were tested for consistency with the metacommunity paradigms of species sorting and neutral dynamics. Thirty senesced leaves were collected from the forest floor (O horizon) in replicate upland forest, riparian forest and vernal pool habitats. We quantified spatial distance between leaves, and fungal community composition was assayed by terminal restriction fragment length polymorphism. Significant distance‐decay relationships were detected at all but one upland site. This is the first study where changes in fungal community composition were quantified across discrete adjacent habitat patches, providing evidence that fungal distance decay is operational at a scale of centimetres. Although leaves of differing lignin contents were sampled from each site, leaf type was not consistently important in explaining variation in fungal community composition. However, depth of a leaf within the forest floor significantly influenced community composition at five of six sites. Environmental heterogeneity associated with depth could include moisture gradients, relative influence of soil or spore colonization, and impact of forest floor biotic community (i.e. collembola and earthworms). Because the influence of spatial distance and depth on fungal community composition could not be disentangled, both species‐sorting and neutral processes may be embedded within the distance‐decay relationships that we found.
Summary
This study utilized individual senesced sugar maple and beech leaves as natural sampling units within which to quantify saprotrophic fungal diversity. Quantifying communities in individual ...leaves allowed us to determine if fungi display a classic taxa–area relationship (species richness increasing with area). We found a significant taxa–area relationship for sugar maple leaves, but not beech leaves, consistent with Wright's species‐energy theory. This suggests that energy availability as affected plant biochemistry is a key factor regulating the scaling relationships of fungal diversity. We also compared taxa rank abundance distributions to models associated with niche or neutral theories of community assembly, and tested the influence of leaf type as an environmental niche factor controlling fungal community composition. Among rank abundance distribution models, the zero‐sum model derived from neutral theory showed the best fit to our data. Leaf type explained only 5% of the variability in community composition. Habitat (vernal pool, upland or riparian forest floor) and site of collection explained > 40%, but could be attributed to either niche or neutral processes. Hence, although niche dynamics may regulate fungal communities at the habitat scale, our evidence points towards neutral assembly of saprotrophic fungi on individual leaves, with energy availability constraining the taxa–area relationship.
There has been a significant shift from the use of animals in biomedical training exercises toward simulation-based education methods. The transition has been driven by technological advances, ...empirical evidence of improved student outcomes, cost-effectiveness, and a growing concern for the welfare of animals. These factors have spurred policy changes worldwide in how medical and science curricula are delivered. We detail how some of these policy changes evolved and comment on the future direction of simulation-based education and its implications for healthcare providers, instructors, and the general public.
The aim of the study was to evaluate for an association between the number of voluntary mannequin simulation sessions completed during the school year with scores on a year-end diagnostic reasoning ...assessment among second-year medical students.
This is retrospective analysis of participation in 0 to 8 extracurricular mannequin simulation sessions on diagnostic reasoning assessed among 129 second-year medical students in an end-of-year evaluation. For the final skills assessment, 2 physicians measured students' ability to reason through a standardized case encounter using the Diagnostic Justification (DXJ) instrument (4 categories each scored 0-3 by raters reviewing students' postencounter written summaries). Rater scores were averaged for a total DXJ score (0-12). To provide additional baseline comparison, zero participation students were divided into 2 groups based on intent to participate: those who signed up for extracurricular sessions but never attended versus those who never expressed interest. Scores across the attendance groups were compared with an analysis of variance and trend analysis.
The class DXJ mean equaled 7.56, with a standard deviation of 2.78 and range of 0 to 12. Post hoc analysis after a significant analysis of variance (F = 4.91, df = 8, 128, P < 0.001) showed those participating in 1 or more extracurricular sessions had significantly higher DXJ scores than those not participating. Students doing 7 extracurricular sessions had significantly higher DXJ scores than those doing 0 and 2 (P < 0.05). Zero attendance groups were not different. A significant linear trend (R = 0.48, F = 38.0, df = 1, 127, P < 0.001) was found with 9 groups. A significant quadratic effect, like a dose-response pattern, was found (F = 18.1, df = 2, 125, P < 0.001) in an analysis including both zero attendance groups, a low (1-4 extracurricular sessions) group and a high (5-8) group.
Higher year-end diagnostic reasoning scores were associated with increased voluntary participation in extracurricular mannequin-based simulation exercises in an approximate dose-response pattern.
The aim of this study is to determine if COPD patients undergoing lung resection with perioperative β-blocker use are more likely to suffer postoperative COPD exacerbations than those that did not ...receive perioperative β-blockers. Methods. A historical cohort study of COPD patients, undergoing lung resection surgery at Memorial Sloan-Kettering Cancer Center between 2002 and 2006. Primary outcomes were the rate of postoperative COPD exacerbations, defined as any initiation or increase of glucocorticoids for documented bronchospasm. Results. 520 patients with COPD were identified who underwent lung resection. Of these, 205 (39%) received perioperative β-blockers and 315 (61%) did not. COPD was mild among 361 patients (69% of all patients), moderate in 117 patients (23%), and severe in 42 patients (8%). COPD exacerbations occurred among 11 (5.4%) patients who received perioperative β-blockers and among 20 (6.3%) patients who did not. Secondary outcomes, which included respiratory failure, 30-day mortality, and the presence or absence of any cardiovascular complication, ICU transfer, cardiovascular complication, or readmission within 30 days, did not differ in prevalence between the two groups. Conclusions. This study implies that perioperative β-blockers use among COPD patients undergoing lung resection surgery does not impact the rate of exacerbations.
Pulmonary complications occur in half of allogeneic bone marrow transplantation (BMT) patients. The incidence of these complications has been reduced by prophylaxis against Pneumocystis carinii ...pneumonia, preemptive therapy in patients at high risk for cytomegalovirus (CMV) reactivation, and, more recently, screening for serum CMV antigen. Since fiberoptic bronchoscopy (FOB) has historically been the primary diagnostic test to evaluate BMT patients with pulmonary disease, a review was performed to determine the impact, if any, that current prophylaxis and screening policies may have had on FOB utility.
The records of 174 adult patients undergoing BMT between January 1997 and December 1999 were reviewed to determine the diagnostic yield of FOB and the frequency by which FOB altered management.
Sixty-one patients underwent 76 bronchoscopies. FOB was diagnostic in 32 patients (42.1% of cases) and directly changed management in 24 patients (31.6% of cases). Half of these changes included the withdrawal of an antimicrobial agent. The most common findings were infection (32 cases) and diffuse alveolar hemorrhage (6 cases). CMV was the most prevalent infection identified, but FOB resulted in the addition of antiviral therapy to only two patients. P carinii pneumonia was not diagnosed in any patient studied.
These data suggest a changing spectrum of pulmonary disease in BMT patients. FOB has limited impact on the diagnoses of CMV disease or P carinii pneumonia with current prophylaxis and screening strategies. It may be useful in identifying other infectious etiologies and in eliminating unnecessary antimicrobials.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Objective
The objective of this study was to determine the public's likelihood of being willing to use an emergency department (ED) for urgent/emergent illness during the coronavirus disease 2019 ...(COVID‐19) pandemic.
Methods
An institutional review board–approved, cross‐sectional survey of a non‐probability sample from Amazon Mechanical Turk was administered May 24–25, 2020. Change in self‐reported willingness to use an ED before and during the pandemic (primary outcome) was assessed via McNemar's test; COVID‐19 knowledge and perceptions were secondary outcomes.
Results
There were 855 survey participants (466 54.5% male; 699 81.8% White; median age 39). Proportion reporting likelihood to use the ED pre‐pandemic (71% 604/855) decreased significantly during the pandemic (49% 417/855; P < 0.001); those unlikely to visit the ED increased significantly during the pandemic (41% 347/855 vs 22% 417/855, P < 0.001). Participants were unlikely to use the ED during the pandemic if they were unlikely to use it pre‐pandemic (adjusted odds ratio, 4.55; 95% confidence interval, 3.09–6.7) or correctly answered more COVID‐19 knowledge questions (adjusted odds ratio, 1.37; 95% confidence interval, 1.17–1.60). Furthermore, 23.4% (n = 200) of respondents believed the pandemic was not a serious threat to society. Respondents with higher COVID‐19 knowledge scores were more likely to view the pandemic as serious (odds ratio, 1.57; 95% confidence interval, 1.36–1.82).
Conclusions
This survey study investigated the public's willingness to use the ED during the COVID‐19 pandemic. Only 49% of survey respondents were willing to visit the ED during a pandemic if they felt ill compared with 71% before the pandemic.
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