Habitat use of Amazonian birds varies by age and foraging guild along a disturbance gradient.

Patterns of habitat use directly influence a species' fitness, yet for many species an individual's age can influence patterns of habitat use. However, in tropical rainforests, which host the greatest terrestrial species diversity, little is known about how age classes of different species use different adjacent habitats of varying quality. We use long-term mist net data from the Amazon rainforest to assess patterns of habitat use among adult, adolescent (teenage) and young understory birds in forest fragments, primary and secondary forest at the Biological Dynamics of Forest Fragments Project in Brazil. Insectivore adults were most common in primary forest, adolescents were equally likely in primary and secondary forest, and all ages were the least common in forest fragments. In contrast to insectivores, frugivores and omnivores showed no differences among all three habitat types. Our results illustrate potential ideal despotic distributions among breeding populations of some guilds of understory birds where adult insectivores may competitively exclude adolescent individuals from primary forest. Secondary forest recovery appears to hold promise as a breeding habitat for frugivore and omnivore species but only as a pre-breeding habitat for insectivores, but as the forest ages, the demographic structure of bird populations should match that of primary forest.

Factors associated with discharge against medical advice among acute stroke patients: Analysis of the Nationwide Emergency Department Sample.

BACKGROUND: Patients discharged against medical advice have been shown to have worse outcomes across a host of different conditions. However, risk factors related to an increased odds of discharge against medical advice remain understudied in patients who suffer from acute cerebral infarction. METHODS: We retrospectively examined the 2019 National Emergency Department Sample Database for stroke patients. Multivariable logistic regression was used to estimate associations between patient- and hospital-level factors and the outcome of discharge against medical advice. RESULTS: Of the 603,623 encounters for acute ischemic stroke, 8858 (1.5%) were discharged against medical advice. Predictors of discharge against medical advice were lower income quartile and having either Medicaid insurance (odds ratio [OR] 1.32, 95% confidence interval [CI] 1.10-1.58) or being uninsured (OR 1.28, 95% CI 1.03-1.58). Vascular comorbidities associated with discharge against medical advice included prior tobacco use (OR 1.60, 95%CI 1.45-1.78) and coronary artery disease (OR 1.19, 95% CI 1.04-1.35). Treatment with thrombectomy (OR 0.33, 95% CI 0.13-0.78) or systemic thrombolysis (OR 0.39, 95% CI 0.23-0.66) was inversely associated with discharge against medical advice. A high modified Charlson Comorbidity Index (3+ vs. 0, OR 0.49, 95% CI 0.42-0.56) was also associated with a lower odds of discharge against medical advice. Presenting to a Northeastern hospital had the highest rate of discharge against medical advice, when compared to other regions (p<0.05). CONCLUSIONS: Certain patient-level, socioeconomic, and regional factors were associated with discharge against medical advice following acute stroke. These patient and systems-level factors warrant heightened attention in order to optimize acute care and secondary prevention strategies.

Predictors of inpatient admission likelihood and prolonged length of stay among cerebrovascular disease patients: A nationwide emergency department sample analysis.

PURPOSE: To examine the hospital- and patient-related factors associated with increased likelihood of inpatient admission and extended hospitalization. METHODS: We applied multivariate logistic regression to a subset of ED hospital and patient characteristics linearly extrapolated from the 2019 National Emergency Department Sample database (n=626,508). Patient characteristics with 10 or fewer ED visits after national extrapolation were not reported in the current study to maintain patient confidentiality, in accordance with the HCUP Data Use Agreement. All selected ED visits represented a primary diagnosis of CVD (ICD-10 codes 160-168). All reported hospital and patient characteristics were subject to adjustment for covariates. P-values < 0.05 were considered statistically significant. MAIN FINDINGS: Medicare beneficiaries report higher inpatient admission rates than uninsured OR 0.81 (0.73-0.91) and privately insured OR 0.86 (0.79-0.94) individuals. Black and Native-American patients were 37% and 55% more likely to be hospitalized long (>75th percentile) (OR 1.37 [1.25-1.50], OR 1.55 [1.14-2.10]). Northeast emergency departments reported an increased odds of admission compared to the Midwest OR (0.40-0.62), South OR 0.79 (0.63-0.98) and West OR 0.52 (0.39-0.69). Patients with multiple comorbidities (mCCI = 3+) were 226% more likely to have a longer stay OR 3.26 (3.09-3.45) than patients presenting with zero or few comorbidities. Level I, II, and III trauma centers report distinctly high odds of inpatient admission (OR 3.54 [2.84-4.42], OR 2.68 [2.14-3.35], OR 1.51 [1.25-1.84]). PRINCIPAL CONCLUSIONS: Likelihoods of inpatient admission and long hospital stays were observably stratified through multiple, independently acting hospital and patient characteristics. Significant associations were stratified by race/ethnicity, location, and clinical presentation, among others. Attention to the factors reported here may serve well to mitigate emergency department crowding and its sobering impact on United States healthcare systems and patients.

Outcomes following thrombectomy for acute large vessel occlusion beyond 24 hours or with unknown time of onset.

BACKGROUND: Endovascular thrombectomy (EVT) is recommended in medically eligible patients with large vessel occlusions (LVO) within 24 hours of symptom onset. While there is evidence that EVT ≥24h after last known well (LKW) is associated with favorable outcomes in patients who meet DAWN/DEFUSE-3 criteria, it is unknown if more liberal criteria can be applied. METHODS: A single center, prospective observational cohort of consecutive adult stroke patients was queried for symptomatic occlusions of the internal carotid (ICA) or proximal middle cerebral (M1) arteries (October 2019-January 2022), with a National Institutes of Health Stroke Scale (NIHSS) ≥6, pre-stroke modified Rankin Scale (mRS) 0-2, and Alberta Stroke Program Early Computed Tomography Scale score 3-10. These inclusion criteria were extrapolated from recently published data indicating a benefit with EVT with more liberal patient selection. Patients who underwent EVT ≥24h after LKW were compared against those treated medically. The primary outcome was a good functional outcome (90-day mRS 0-2), which was evaluated using multivariable logistic regression. RESULTS: Of the 27 included patients, the median age was 65y (IQR 49-76) with a median NIHSS of 15 (IQR 8-26), and 17 (63.0%) underwent EVT (median LKW-to-puncture 35.5h (IQR 26.9-65.8h). The primary outcome was no different with EVT in unadjusted regression (OR 1.17, 95%CI 0.17-8.09), and there remained no association across all multivariable models tested. Age, pre-stroke disability, and M1 occlusions were non-significantly associated with the primary outcome (p>0.05). There was a non-significant trend indicating a favorable shift in 90-day mRS with EVT (proportional OR 2.04, 95%CI 0.44-9.48). CONCLUSIONS: Using more liberal inclusion criteria for EVT in the ultra-extended window, there was no statistically significant difference in the rate of good functional outcome with EVT. Larger studies are called upon to evaluate outcomes when more liberal criteria are used to assess thrombectomy eligibility.

Differential thrombectomy utilization across hospital classifications in the United States.

OBJECTIVES: To determine hospital-level factors associated with thrombectomy uptake. MATERIALS AND METHODS: The Nationwide Emergency Department Sample was retrospectively queried to determine the total number of thrombectomies performed based on different hospital characteristics. Joint point analysis was used to determine which years were associated with significant increases in the number of high-volume thrombectomy centers (ostensibly defined as >50 thrombectomies/year), thrombectomy-capable centers (>15 thrombectomies/year), and total number of thrombectomies performed. Multivariable logistic regression was used to determine hospital factors associated with having an increased odds of performing thrombectomies, and of being classified as a high-volume thrombectomy or a thrombectomy-capable center. RESULTS: Between 2007-2020 there was a stepwise increase in the number of thrombectomy-capable and high-volume thrombectomy centers in the United States. In 2020, there were a total of 15,705 thrombectomies performed, with 89 high-volume thrombectomy centers, and 359 thrombectomy-capable centers. The number of thrombectomy-capable centers significantly increased after 2011. After 2013 and 2016 there was a significant change in the growth rate of high-volume thrombectomy centers. There was also a significant increase in the total number of thrombectomies performed after 2016. Hospital characteristics that were associated with an increased likelihood of being classified as thrombectomy-capable or high-volume included trauma level 1 and 2 hospitals. CONCLUSIONS: Between 2007 and 2020, there was a marked growth in thrombectomy utilization for acute ischemic stroke. This growth outpaced new diagnoses of ischemic stroke, and was driven largely by certain hospital types, with the greatest rises following seminal publications of positive randomized thrombectomy trials.

Subcortical infarcts in patients with nonstenotic cervical atherosclerotic disease.

BACKGROUND: Prior studies have elucidated a relationship between nonstenotic plaque in patients with cryptogenic embolic infarcts with a largely cortical topology, however, it is unclear if nonstenotic cervical internal carotid artery (ICA) plaque is relevant in subcortical cryptogenic infarct patterns. METHODS: A nested cohort of consecutive patients with anterior, unilateral, and subcortical infarcts without an identifiable embolic source were identified from a prospective stroke registry (September 2019 - June 2021). Patients with extracranial stenosis >50% or cardiac sources of embolism were excluded. Patients with computed tomography angiography were included and comparisons were made according to the infarct pattern being lacunar versus non-lacunar. Prevalence estimates for cervical internal carotid artery (ICA) plaque presence were estimated with 95% confidence intervals (CI), and differences in plaque thickness and features were compared between sides. RESULTS: Of the 1684 who were screened, 141 met inclusion criteria (n=80 due to small vessel disease, n=61 cryptogenic). The median age was 66y (interquartile range, IQR 58-73) and the National Institutes of Health Stroke Scale score was 3 (IQR 1-5). There was a higher probability of finding excess plaque ipsilateral to the stroke (41.1%, 95% CI 33.3-49.3%) than finding excess contralateral plaque (29.1%, 95% CI 22.2-37.1%; p=0.03), but this was driven by patients with non-lacunar infarcts (excess ipsilateral vs. contralateral plaque frequency of 49.2% vs. 14.8%, p<0.001) rather than lacunar infarcts (35.0% vs. 40.0%, p=0.51). CONCLUSIONS: The probability of finding ipsilateral, nonstenotic carotid plaque in patients with subcortical cryptogenic strokes exceeds the probability of contralateral plaque and is driven by larger subcortical infarcts, classically defined as being cryptogenic. Approximately 1 in 3 unilateral anterior subcortical infarcts may be due to nonstenotic ICA plaque.

AVONET: morphological, ecological and geographical data for all birds.

Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species-level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity.

Long-term changes in avian biomass and functional diversity within disturbed and undisturbed Amazonian rainforest.

Recent long-term studies in protected areas have revealed the loss of biodiversity, yet the ramifications for ecosystem health and resilience remain unknown. Here, we investigate how the loss of understory birds, in the lowest stratum of the forest, affects avian biomass and functional diversity in the Amazon rainforest. Across approximately 30 years in the Biological Dynamics of Forest Fragments Project, we used a historical baseline of avian communities to contrast the avian communities in today's primary forest with those in modern disturbed habitat. We found that in primary rainforest, the reduced abundance of insectivorous species led to reduced functional diversity, but no reduction of biomass, indicating that species with similar functional traits are less likely to coexist in modern primary forests. Because today's forests contain fewer functionally redundant species-those with similar traits-we argue that avian communities in modern primary Amazonian rainforests are less resilient, which may ultimately disrupt the ecosystem in dynamic and unforeseen ways.

Clinical and radiographic phenotypes of patients with multifocal subcortical versus cortical cerebral infarcts.

BACKGROUND AND PURPOSE: Infarct topology is a key determinant in classification of a stroke as potentially embolic, with cortical and multifocal lesions being presumed embolic. Whether isolated subcortical multifocal infarcts are likely embolic has not been well studied. METHODS: A prospective, single-center cohort study of consecutive patients with acute multifocal strokes confirmed on diffusion-weighting imaging (DWI) was queried, and patients compared according to the presence of isolated subcortical infarct topology versus cortical ± subcortical topology. Descriptive statistics and multivariable logistic regression were used to determine independent predictors of cryptogenic, subcortical infarcts. RESULTS: Of 1739 patients screened, 743 had complete diagnostic testing with DWI evidence of acute infarction, 183 (24.6%) of whom had a multifocal stroke pattern. Isolated subcortical involvement was disproportionate among patients with ESUS (64.9%) when compared to patients with cardioembolic (24.3%) or large vessel disease (10.8%, p<0.01). Following multivariable adjustment, independent predictors of isolated subcortical multifocal infarction were milder strokes (OR 0.94, 95%CI 0.89-0.98) and higher grade Fazekas score (OR 2.32, 95%CI 1.02-5.29), while cardioembolism (OR 0.30, 95%CI 0.08-1.13) and large vessel disease (OR 0.27, 95%CI 0.08-0.91) remained inversely associated (as compared to ESUS). CONCLUSIONS: These data suggest that multifocal subcortical infarctions are less likely to have an associated proximal embolic source than multifocal infarctions with cortical involvement. The strong association with chronic microvascular disease suggests this topology is more consistent with acute-on-chronic microvascular injury rather than an occult embolic source.

Embolic infarct topology differs between atrial fibrillation subtypes and embolic stroke of undetermined source.

BACKGROUND: The lack of superiority of anticoagulation over antiplatelet therapy in embolic stroke of undetermined source (ESUS) may be in part due to the misclassification of radiographic ESUS patterns as cardioembolic. In this imaging analysis, we sought to differentiate clinical and radiographic patterns of ESUS patients from patterns in patients with a highly probable cardioembolic source. MATERIALS & METHODS: A prospective registry of consecutive adults with acute infarction on diffusion-weighted magnetic resonance imaging was queried. Patients with infarctions due to small vessel disease, large vessel disease, and other causes were excluded. Multivariable logistic regression was used to identify independent predictors of two potentially embolic patterns: (1) multifocal and (2) cortical lesions, comparing patients with ESUS against those with atrial fibrillation (AF). RESULTS: Among 1243 screened patients, 343 (27.6%) experienced strokes due to ESUS or AF. Prior to the index stroke, patients with AF as compared to ESUS were older (median 75 vs. 65, p<0.01) and had more heart failure (25.9% vs. 8.4%, p<0.01). The odds of multifocal infarction were the same between patients with ESUS and both AF subtypes (p>0.05), however, cortical involvement was more associated with both AF versus ESUS (77.7% vs. 65.7%, P=0.02). A higher Fazekas grade of white matter disease was inversely associated with cortical infarction among included patients (aOR 0.77, 95% CI 0.62-0.96). CONCLUSION: Cortical infarctions were twice as common among patients with AF versus ESUS. Subcortical infarct topography was strongly associated with chronic microvascular ischemic changes and therefore may not represent embolic phenomena. Larger-scale investigations are warranted to discern whether large or multifocal subcortical infarcts ought to be excluded from the ESUS designation.

Unique Clinicopathologic Subclassifiers of Cryptogenic Cerebral Emboli.

INTRODUCTION: Ipsilateral nonstenotic (<50%) internal carotid artery (ICA) plaque, cardiac atriopathy, and patent foramen ovale (PFO) may account for a substantial proportion of embolic stroke of undetermined source (ESUS). METHODS: Consecutive stroke patients at our center (2019-2021) with unilateral, anterior circulation ESUS were categorized into the following mutually exclusive etiologies: (1) nonstenotic ipsilateral ICA plaque (NSP, ≥3mm in maximal axial diameter), (2) sex-adjusted mod-to-severe left atrial enlargement (LAE), (3) PFO, and (4) "occult ESUS" (patients who failed to meet criteria for these 3 groups). Descriptive statistics and multivariable logistic regression were used to model group characteristics. RESULTS: Of 132 included patients, the median age was 65 (IQR 56-73), 74 (56%) of whom were White, and 54 (41%) were female. Twenty-one patients (16%) had NSP proximal to the infarct territory, 17 (13%) had LAE, 9 (7%) had a PFO, and 85 (64%) had no other mechanism. Patients with LAE were older (p=0.004), and had more frequent intracranial occlusions of the internal carotid and proximal middle cerebral artery (p=0.048), while tobacco use was most commonly found among patients with NSP (75%) when compared to other ESUS groups (p=0.02). Five of 9 patients with LAE who underwent outpatient telemetry had paroxysmal atrial fibrillation (56%), while zero patients with PFO or NSP had paroxysmal atrial fibrillation (p=0.005). Older age (adjusted OR [aOR] 1.05, 95%CI 1.03-1.07), coronary artery disease (aOR 3.22, 95%CI 1.61-6.44) and hypertension (aOR 2.16, 95%CI 1.14-4.06) were independently associated with LAE, while only tobacco use was associated with NSP when compared to other ESUS subclassifiers (OR 3.18, 95%CI 1.08-0.42). Age and tobacco use were both inversely associated with PFO (aOR 0.93, 95%CI 0.88-0.98, and aOR 0.10, 95%CI 0.02-0.90, respectively). CONCLUSIONS: Certain clinical and radiographic features may be useful in predicting the proximal source of occult cerebral emboli, and can be used for cost-effective outpatient diagnostic testing.

Long-term change in the avifauna of undisturbed Amazonian rainforest: ground-foraging birds disappear and the baseline shifts.

How are rainforest birds faring in the Anthropocene? We use bird captures spanning > 35 years from 55 sites within a vast area of intact Amazonian rainforest to reveal reduced abundance of terrestrial and near-ground insectivores in the absence of deforestation, edge effects or other direct anthropogenic landscape change. Because undisturbed forest includes far fewer terrestrial and near-ground insectivores than it did historically, today's fragments and second growth are more impoverished than shown by comparisons with modern 'control' sites. Any goals for bird community recovery in Amazonian second growth should recognise that a modern bird community will inevitably differ from a baseline from > 35 years ago. Abundance patterns driven by landscape change may be the most conspicuous manifestation of human activity, but biodiversity declines in undisturbed forest represent hidden losses, possibly driven by climate change, that may be pervasive in intact Amazonian forests and other systems considered to be undisturbed.

Prenatal use of medications for gastroesophageal reflux disease and early childhood fracture risk.

BACKGROUND: Gastroesophageal reflux disease is a common condition in pregnancy and is often managed with medications. Specific medications have been linked to osteoporosis and fragility fracture in older adults. This study assessed whether maternal use of antireflux medications is associated with early childhood fracture. METHODS: TRICARE beneficiaries during pregnancy were retrospectively identified using the Military Health System Data Repository and pharmacy data. Mother and infant data were linked; children with continuous enrollment for the first 5 years of life were included. Differences in the children's fracture risk were analyzed through multivariate analysis, adjusting for region, rank, and military branch of service. RESULTS: A total of 378 150 patients comprised the final cohort with 3.3% (n = 12 479) prescribed antireflux medications during pregnancy. A significant decrease in fracture rate was found among children of women who were prescribed antireflux medications during pregnancy compared with those who were not (0.8% vs 1.2%, RR = 0.70, 95% CI 0.58-0.85). There was no difference in fracture risk between histamine type 2 receptor antagonists and proton pump inhibitors. A significantly increased fracture incidence was seen in pregnancies with multiple gestations (RR = 1.38, 95% CI 1.04-1.85). There was no identified difference in fracture risk for women with gestational diabetes, preeclampsia, preterm or low birthweight, chronic hypertension, induction, or breech presentation when compared to women without these conditions. CONCLUSIONS: We found no increase in early childhood fracture risk with maternal antireflux medication use. This suggests that prenatal exposure to antireflux medications does not affect fetal bones to a clinically significant extent.

Early Pediatric Fractures in a Universally Insured Population within the United States.

BACKGROUND: Musculoskeletal injury, including fracture, is one of the most common causes of morbidity in pediatric patients. The purpose of this epidemiologic study is to determine the prevalence and risk factors for fracture in a large cohort of pediatric patients under the age of 5. RESULTS: Of the 233,869 patients included in the study, 13,698 fractures were identified in 10,889 patients. The highest annual incidence was in the 4 year old age group with a rate of 24.2 fractures per 1000 children. The annual incidence within all age groups was 11.7 fractures per 1000 children. The two most common fractures were forearm and humerus fractures. Fracture incidence was increased in male children, patients who live outside the US, and in Caucasian patients. An increase in rate of fracture was also identified in children of officers when compared with children of enlisted service members. There were 35 abuse related fractures in our cohort, with 19 of them occurring in children less than 1 year old. Only three children in our cohort had Osteogenesis Imperfecta. CONCLUSION: Fractures are common injuries in young children with an incidence over the first 5 years of life of 5.86%. Multiple risk factors were also identified including age, race, geographic location and socioeconomic status. The results of this study are an important contribution to epidemiologic and public health literature and serve to characterize the incidence of and risk factors for sustaining an early childhood fracture.

Proximal Femur Hounsfield Units on CT Colonoscopy Correlate With Dual-energy X-ray Absorptiometry.

BACKGROUND: Quantifying bone mineral density (BMD) on CT using commercial software demonstrates good-to-excellent correlations with dual-energy x-ray absorptiometry (DEXA) results. However, previous techniques to measure Hounsfield units (HUs) within the proximal femur demonstrate less successful correlation with DEXA results. An effective method of measuring HUs of the proximal femur from CT colonoscopy might allow for opportunistic osteoporosis screening. QUESTIONS/PURPOSES: (1) Do proximal femur HU measurements from CT colonoscopy correlate with proximal femur DEXA results? (2) How effective is our single HU measurement technique in estimating the likelihood of overall low BMD? (3) Does the relationship between our comprehensive HU measurement and DEXA results change based on age, sex, or time between studies? METHODS: This retrospective study investigated the measurement of HU of the femur obtained on CT colonoscopy studies compared with DEXA results. Between 2010 and 2017, five centers performed 9085 CT colonoscopy studies; of those, 277 (3%) also had available DEXA results and were included in this study, whereas 8809 (97%) were excluded for inadequate CT imaging, lack of DEXA screening, or lack of proximal femur DEXA results. The median number of days between CT colonoscopy and DEXA scan was 595 days; no patient was excluded based on time between scans because bone remodeling is a long-term process and this allowed subgroup analysis based on time between scans. Two reviewers performed HU measurements at four points within the proximal femur on the CT colonoscopy imaging and intraclass correlation coefficients were used to evaluate interrater reliability. We used Pearson correlation coefficients to compare the comprehensive (average of eight measurements) and a single HU measurement with each DEXA result-proximal femur BMD, proximal femur T-score, femoral neck BMD, and femoral neck T-score-to identify the best measurement technique within this study. Based on their lowest DEXA T-score, we stratified patients to a diagnosis of osteoporosis, osteopenia, or normal BMD. We then calculated the area under the receiver operator characteristic curves (AUCs) to evaluate the classification ability of a single HU value to identify possible threshold(s) for detecting low BMD. For each subgroup analysis, we calculated Pearson correlation coefficients between DEXA and HUs and evaluated each subgroup's contribution to the overall predictive model using an interaction test in a linear regression model. RESULTS: The Pearson correlation coefficient between both the comprehensive and single HU measurements was highest compared with the proximal femur T-score at 0.75 (95% confidence interval [CI], 0.69-0.80) and 0.74 (95% CI, 0.68-0.79), respectively. Interobserver reliability, measured with intraclass correlation coefficients, for the comprehensive and single HU measurements was 0.97 (95% CI, 0.72-0.99) and 0.96 (95% CI, 0.89-0.98), respectively. Based on DEXA results, 20 patients were osteoporotic, 167 had osteopenia, and 90 patients had normal BMD. The mean comprehensive HU for patients with osteoporosis was 70 ± 30 HUs; for patients with osteopenia, it was 110 ± 36 HUs; and for patients with normal BMD, it was 158 ± 43 HUs (p < 0.001). The AUC of the single HU model was 0.82 (95% CI, 0.77-0.87). A threshold of 214 HUs is 100% sensitive and 59 HUs is 100% specific to identify low BMD; a threshold of 113 HUs provided 73% sensitivity and 76% specificity. When stratified by decade age groups, each decade age group demonstrated a positive correlation between the comprehensive HU and proximal femur T-score, ranging between 0.71 and 0.83 (95% CI, 0.59-0.91). Further subgroup analysis similarly demonstrated a positive correlation between the comprehensive HU and proximal femur T-score when stratified by > 6 months or < 6 months between CT and DEXA (0.75; 95% CI, 0.62-0.84) as well as when stratified by sex (0.70-0.76; 95% CI, 0.48-0.81). The linear regression model demonstrated that the overall positive correlation coefficient between HUs and the proximal femur T-score is not influenced by any subgroup. CONCLUSIONS: Our measurement technique provides a reproducible measurement of HUs within the proximal femur HUs on CT colonoscopy. Hounsfield units of the proximal femur based on this technique can predict low BMD. These CT scans are frequently performed before initial DEXA scans are done and therefore may lead to earlier recognition of low BMD. Future research is needed to validate these results in larger studies and to determine if these results can anticipate future fracture risk. LEVEL OF EVIDENCE: Level III, diagnostic study.

Glenoid neck Hounsfield units on computed tomography can accurately identify patients with low bone mineral density.

BACKGROUND: Osteoporosis is a costly and morbid disease with the first presentation often with a fragility fracture. The purpose of this study was to assess whether Hounsfield unit (HU) measurements on shoulder computed tomography could identify patients at risk of osteoporosis and aid in its diagnosis. METHODS: We identified patients who had both a computed tomography scan of the glenoid and a dual-energy x-ray absorptiometry scan. Dual-energy x-ray absorptiometry results and HU measurements of the patients' glenoid were recorded. Differences in HU measurements between patients with normal and abnormal central bone mineral density (BMD) were assessed. Correlations were calculated, and receiver operating characteristics were examined. RESULTS: A total of 51 glenoids met the criteria. The mean glenoid HU measurement was 140.6 (95% confidence interval [CI], 120.1-161.1) in the osteoporotic group, 168.1 (95% CI, 152.7-183.5) in the osteopenic group, and 233.2 (95% CI, 210.1-256.4) in the normal BMD group (P < .001). There was a significant correlation between mean glenoid HU measurement and patients' t scores in the femoral neck (r = 0.581), total hip (r = 0.524), and lumbar spine (r = 0.345). The area under the receiver operating characteristic curve was 0.918. With 197 HUs used as the cutoff for diagnosis of abnormal BMD, the positive predictive value was 96.6%. With 257.1 HUs used as the cutoff, the negative predictive value was 100%. CONCLUSION: A patient with an HU measurement below 197 has a 97% chance of having low BMD, and a patient with a measurement over 257 likely has normal BMD. In patients with measurements between these values, a definitive diagnosis should be aggressively pursued. Opportunistic screening for a modifiable disease that has significant morbidity and mortality rates at no additional cost, radiation, or time is of great value.

Bottom-up processes influence the demography and life-cycle phenology of Hawaiian bird communities.

Changes in climate can indirectly regulate populations at higher trophic levels by influencing the availability of food resources in the lower reaches of the food web. As such, species that rely on fruit and nectar food resources may be particularly sensitive to these bottom-up perturbations due to the strength of their trophic linkages with climatically-influenced plants. To measure the influence of climatically-mediated, bottom-up processes, we used climate, bird capture, bird count, and plant phenology data from the Big Island of Hawaii to construct a series of structural equation and abundance models. Our results suggest that fruit and nectar-eating birds arrange life cycle events around climatically-influenced food resources, while some of these same food resources also influence seasonal patterns of abundance. This trend was particularly strong for two native nectarivores, 'I'iwi and 'Apapane, where we found that the dissimilar timing of molting and breeding activity was associated with peak abundance of the two most common flowers at our study site which, in turn, were each driven by dissimilar climatic cues. Given the rapidly changing Hawaiian climate, we suggest that determining behavioral plasticity, or evolutionary capacity of birds to mitigate changes in climatically-influenced food resources, should be recognized as a future research priority.

Changes in the apparent survival of a tropical bird in response to the El Niño Southern Oscillation in mature and young forest in Costa Rica.

The effects of habitat alteration and climatic instability have resulted in the loss of bird populations throughout the globe. Tropical birds in particular may be sensitive to climate and habitat change because of their niche specialization, often sedentary nature, and unique life-cycle phenologies. Despite the potential influence of habitat and climatic interactions on tropical birds, we lack comparisons of avian demographics from variably aged forests subject to different climatic phenomena. Here, we measured relationships between forest type and climatic perturbations on White-collared Manakin (Manacus candei), a frugivorous tropical bird, by using 12 years of capture data in young and mature forests in northeastern Costa Rica. We used Cormack-Jolly-Seber models and an analysis of deviance to contrast the influence of the El Niño Southern Oscillation (ENSO) on manakin survival. We found that ENSO had little effect on manakin survival in mature forests. Conversely, in young forests, ENSO explained 79% of the variation where dry El Niño events negatively influenced manikin survival. We believe mature forest mitigated negative effects of dry El Niño periods and can serve as refugia for some species by buffering birds from climatic instability. Our results represent the first published documentation that ENSO influences the survival of a resident Neotropic landbird.

Analysis of Orthopaedic Research Produced During the Wars in Iraq and Afghanistan.

BACKGROUND: Military orthopaedic surgeons have published a substantial amount of original research based on our care of combat-wounded service members and related studies during the wars in Iraq and Afghanistan. However, to our knowledge, the influence of this body of work has not been evaluated bibliometrically, and doing so is important to determine the modern impact of combat casualty research in the wider medical community. QUESTIONS/PURPOSES: We sought to identify the 20 most commonly cited works from military surgeons published during the Iraq and Afghanistan conflicts and analyze them to answer the following questions: (1) What were the subject areas of these 20 articles and what was the 2013 Impact Factor of each journal that published them? (2) How many citations did they receive and what were the characteristics of the journals that cited them? (3) Do the citation analysis results obtained from Google Scholar mirror the results obtained from Thompson-Reuters' Web of Science? METHODS: We searched the Web of Science Citation Index Expanded for relevant original research performed by US military orthopaedic surgeons related to Operation Iraqi Freedom and Operation Enduring Freedom between 2001 and 2014. Articles citing these studies were reviewed using both Web of Science and Google Scholar data. The 20 most cited articles meeting inclusion criteria were identified and analyzed by content domain, frequency of citation, and sources in which they were cited. RESULTS: Nine of these studies examined the epidemiology and outcome of combat injury. Six studies dealt with wound management, wound dehiscence, and formation of heterotopic ossification. Five studies examined infectious complications of combat trauma. The median number of citations garnered by these 20 articles was 41 (range, 28-264) in Web of Science. Other research citing these studies has appeared in 279 different journals, covering 26 different medical and surgical subspecialties, from authors in 31 different countries. Google Scholar contained 97% of the Web of Science citations, but also had 31 duplicate entries and 29 citations with defective links. CONCLUSIONS: Modern combat casualty research by military orthopaedic surgeons is widely cited by researchers in a diverse range of subspecialties and geographic locales. This suggests that the military continues to be a source of innovation that is broadly applicable to civilian medical and surgical practice and should encourage expansion of military-civilian collaboration to maximize the utility of the knowledge gained in the treatment of war trauma. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Decay of interspecific avian flock networks along a disturbance gradient in Amazonia.

Our understanding of how anthropogenic habitat change shapes species interactions is in its infancy. This is in large part because analytical approaches such as network theory have only recently been applied to characterize complex community dynamics. Network models are a powerful tool for quantifying how ecological interactions are affected by habitat modification because they provide metrics that quantify community structure and function. Here, we examine how large-scale habitat alteration has affected ecological interactions among mixed-species flocking birds in Amazonian rainforest. These flocks provide a model system for investigating how habitat heterogeneity influences non-trophic interactions and the subsequent social structure of forest-dependent mixed-species bird flocks. We analyse 21 flock interaction networks throughout a mosaic of primary forest, fragments of varying sizes and secondary forest (SF) at the Biological Dynamics of Forest Fragments Project in central Amazonian Brazil. Habitat type had a strong effect on network structure at the levels of both species and flock. Frequency of associations among species, as summarized by weighted degree, declined with increasing levels of forest fragmentation and SF. At the flock level, clustering coefficients and overall attendance positively correlated with mean vegetation height, indicating a strong effect of habitat structure on flock cohesion and stability. Prior research has shown that trophic interactions are often resilient to large-scale changes in habitat structure because species are ecologically redundant. By contrast, our results suggest that behavioural interactions and the structure of non-trophic networks are highly sensitive to environmental change. Thus, a more nuanced, system-by-system approach may be needed when thinking about the resiliency of ecological networks.