Conceptual Hierarchies Arise from the Dynamics of Learning and Processing: Insights from a Flat Attractor Network

The structure of people’s conceptual knowledge of concrete nouns has traditionally been viewed as hierarchical (Collins & Quillian, 1969). Specifically, superordinate concepts (vegetable) are assumed to reside at a higher level than basic-level concepts (carrot). A feature-based attractor network with a single layer of semantic features developed representations of basic-level and superordinate concepts. No hierarchical structure was built into the network. In Experiment and Simulation 1 the graded structure of categories (typicality ratings) are accounted for by the flat attractor-network. Experiment and Simulation 2 show that, as with basic-level concepts, the model predicts feature verification latencies for superordinate concepts (vegetable ). In Experiment and Simulation 3, counterintuitive findings regarding the temporal dynamics of similarity in semantic priming are explained by the model. By treating both types of concepts the same in terms of representation and learning, the model provides new insights to the similarities and differences between them

Characteristic Mechanisms and Outcome of Cardiopulmonary Arrest in Congestive Heart Failure Patients

Recent studies suggest the mechanism of sudden death in congestive heart failure (CHF) patients is less frequently VT/VF than previously believed. In order to further understand the characteristics and mechanisms of death in CHF patients, we evaluated 146 patients who underwent cardiopulmonary resuscitation during hospitalization for congestive heart failure, ischemic heart disease, and noncardiac causes. Clinical characteristics and outcomes are described below:CHF/CardiacnonCHF/CardiacnoncardiacN302690Age63 (49.71)67 (60.72)63 (29.71)Sex (% male)375860Initial Rhythm N(%)VT/VF7 (25)11 (44)24 (27)Asystole6 (21.4)6 (24)33 (37.5)Bradycardia5 (17.9)2 (8)6 (6.8)EMD6 (21.4)1 (4)13 (148)Other4 (14.3)5 (20)12 (136)ROSC21 (70)13 (50)51 (56.7)Survival to D/C1 (3.3)4 (15.4)2 (2.2)Patients with nonCHF/Cardiac disease had a higher ROSC than patients with CHF and noncardiac diseases (p=0.016). In summary, patients with CHF often experience cardiopulmonary arrest with bradycardic or EMD arrests. Although patients with CHF are resuscitated with a high degree of success their in-hospital survival was low. Furthermore, the high rate of bradycardic and EMD arrests may explain the low in-hospital survival rates

Sampling Bias Overestimates Climate Change Impacts on Forest Growth in the Southwestern United States

Climate−tree growth relationships recorded in annual growth rings have recently been the basis for projecting climate change impacts on forests. However, most trees and sample sites represented in the International Tree-Ring Data Bank (ITRDB) were chosen to maximize climate signal and are characterized by marginal growing conditions not representative of the larger forest ecosystem. We evaluate the magnitude of this potential bias using a spatially unbiased tree-ring network collected by the USFS Forest Inventory and Analysis (FIA) program. We show that U.S. Southwest ITRDB samples overestimate regional forest climate sensitivity by 41–59%, because ITRDB trees were sampled at warmer and drier locations, both at the macro- and micro-site scale, and are systematically older compared to the FIA collection. Although there are uncertainties associated with our statistical approach, projection based on representative FIA samples suggests 29% less of a climate change-induced growth decrease compared to projection based on climate-sensitive ITRDB samples

Heart Rate or Beta-Blocker Dose? Association With Outcomes in Ambulatory Heart Failure Patients With Systolic Dysfunction Results From the HF-ACTION Trial

AbstractObjectivesThis study aimed to compare whether reduced heart rate (HR) or higher beta-blocker (BB) dose affected outcomes to a greater extent in the HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) trial population.BackgroundRecent data have shown that HR is an important modifiable factor in reducing mortality in heart failure (HF) patients. It has also been shown that titration of doses of BBs improves outcomes of morbidity and mortality in chronic HF patients with reduced ejection fraction. We aimed to compare whether reduced HR or higher BB dose affected outcomes to a greater extent in the HF-ACTION trial population.MethodsHF-ACTION was a randomized, multicenter trial enrolling 2,331 ambulatory HF patients with systolic dysfunction (New York Heart Association functional class II to IV, left ventricular ejection fraction <0.35) randomized to exercise training versus usual care, with median follow-up of 2.5 years. BB dose at baseline was standardized by use of carvedilol equivalents. BB dose and HR were analyzed by discrete groups (higher/lower dose; higher/lower HR). The relationship of BB dose, HR, and the primary endpoint of all-cause mortality or all-cause hospitalization and other cardiovascular secondary endpoints were determined before and after adjustment for variables found to be significantly associated with outcome in the HF-ACTION cohort.ResultsThere was a significant inverse relationship between either BB dose (higher was better) or HR (lower was better) and all-cause death or hospitalization in unadjusted analysis; however, only BB dose was significant for improved mortality outcomes. After adjustment for other predictors of outcome, only BB dose remained significant for improving all-cause death or hospitalization. BB dose, but not HR, was associated with improved outcomes of other cardiovascular endpoints in unadjusted analysis but did not remain significant when adjusted for other predictors of outcome in this cohort.ConclusionsThere were more associated improvements in outcomes with higher BB dose than with reduced HR in this well-treated HF cohort with systolic dysfunction, which suggests that titration of BB doses may confer a greater benefit than reduction of HR in such patients. (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training [HF-ACTION]; NCT00047437

Geospatial framework to assess fireline effectiveness for large wildfires in the western USA, A

Includes bibliographical references (pages 16-19).Quantifying fireline effectiveness (FLE) is essential to evaluate the efficiency of large wildfire management strategies to foster institutional learning and improvement in fire management organizations. FLE performance metrics for incident-level evaluation have been developed and applied to a small set of wildfires, but there is a need to understand how widely they vary across incidents to progress towards targets or standards for performance evaluation. Recent efforts to archive spatially explicit fireline records from large wildfires facilitate the application of these metrics to a broad sample of wildfires in different environments. We evaluated fireline outcomes (burned over, held, not engaged) and analyzed incident-scale FLE for 33 large wildfires in the western USA from the 2017 and 2018 fire seasons. FLE performance metrics varied widely across wildfires and often aligned with factors that influence suppression strategy. We propose a performance evaluation framework based on both the held to engaged fireline ratio and the total fireline to perimeter ratio. These two metrics capture whether fireline was placed in locations with high probability of engaging with the wildfire and holding and the relative level of investment in containment compared to wildfire growth. We also identify future research directions to improve understanding of decision quality in a risk-based framework

A combined clinical and biomarker approach to predict diuretic response in acute heart failure

Background: Poor diuretic response in acute heart failure is related to poor clinical outcome. The underlying mechanisms and pathophysiology behind diuretic resistance are incompletely understood. We evaluated a combined approach using clinical characteristics and biomarkers to predict diuretic response in acute heart failure (AHF). Methods and results: We investigated explanatory and predictive models for diuretic response—weight loss at day 4 per 40 mg of furosemide—in 974 patients with AHF included in the PROTECT trial. Biomarkers, addressing multiple pathophysiological pathways, were determined at baseline and after 24 h. An explanatory baseline biomarker model of a poor diuretic response included low potassium, chloride, hemoglobin, myeloperoxidase, and high blood urea nitrogen, albumin, triglycerides, ST2 and neutrophil gelatinase-associated lipocalin (r2 = 0.086). Diuretic response after 24 h (early diuretic response) was a strong predictor of diuretic response (β = 0.467, P &lt; 0.001; r2 = 0.523). Addition of diuretic response after 24 h to biomarkers and clinical characteristics significantly improved the predictive model (r2 = 0.586, P &lt; 0.001). Conclusions: Biomarkers indicate that diuretic unresponsiveness is associated with an atherosclerotic profile with abnormal renal function and electrolytes. However, predicting diuretic response is difficult and biomarkers have limited additive value. Patients at risk of poor diuretic response can be identified by measuring early diuretic response after 24 h

Serum potassium levels and outcome in acute heart failure (data from the PROTECT and COACH trials)

Serum potassium is routinely measured at admission for acute heart failure (AHF), but information on association with clinical variables and prognosis is limited. Potassium measurements at admission were available in 1,867 patients with AHF in the original cohort of 2,033 patients included in the Patients Hospitalized with acute heart failure and Volume Overload to Assess Treatment Effect on Congestion and Renal FuncTion trial. Patients were grouped according to low potassium (&lt;3.5 mEq/l), normal potassium (3.5 to 5.0 mEq/l), and high potassium (&gt;5.0 mEq/l) levels. Results were verified in a validation cohort of 1,023 patients. Mean age of patients was 71 – 11 years, and 66% were men. Low potassium was present in 115 patients (6%), normal potassium in 1,576 (84%), and high potassium in 176 (9%). Potassium levels increased during hospitalization (0.18 – 0.69 mEq/l). Patients with high potassium more often used angiotensin-converting enzyme inhibitors and mineralocorticoid receptor antagonists before admission, had impaired baseline renal function and a better diuretic response (p [ 0.005), independent of mineralocorticoid receptor antagonist usage. During 180-day follow-up, a total of 330 patients (18%) died. Potassium levels at admission showed a univariate linear association with mortality (hazard ratio [log] 2.36, 95% confidence interval 1.07 to 5.23; p [ 0.034) but not after multivariate adjustment. Changes of potassium levels during hospitalization or potassium levels at discharge were not associated with outcome after multivariate analysis. Results in the validation cohort were similar to the index cohort. In conclusion, high potassium levels at admission are associated with an impaired renal function but a better diuretic response. Changes in potassium levels are common, and overall levels increase during hospitalization. In conclusion, potassium levels at admission or its change during hospitalization are not associated with mortality after multivariate adjustment

Prognostic significance of creatinine increases during an acute heart failure admission in patients with and without residual congestion

Background: The importance of a serum creatinine increase, traditionally considered worsening renal function (WRF), during admission for acute heart failure has been recently debated, with data suggesting an interaction between congestion and creatinine changes. Methods and Results: In post hoc analyses, we analyzed the association of WRF with length of hospital stay, 30-day death or cardiovascular/renal readmission and 90-day mortality in the PROTECT study (Placebo-Controlled Randomized Study of the Selective A1 Adenosine Receptor Antagonist Rolofylline for Patients Hospitalized With Acute Decompensated Heart Failure and Volume Overload to Assess Treatment Effect on Congestion and Renal Function). Daily creatinine changes from baseline were categorized as WRF (an increase of 0.3 mg/dL or more) or not. Daily congestion scores were computed by summing scores for orthopnea, edema, and jugular venous pressure. Of the 2033 total patients randomized, 1537 patients had both available at study day 14. Length of hospital stay was longer and 30-day cardiovascular/renal readmission or death more common in patients with WRF. However, these were driven by significant associations in patients with concomitant congestion at the time of assessment of renal function. The mean difference in length of hospital stay because of WRF was 3.51 (95% confidence interval, 1.29–5.73) more days (P=0.0019), and the hazard ratio for WRF on 30-day death or heart failure hospitalization was 1.49 (95% confidence interval, 1.06–2.09) times higher (P=0.0205), in significantly congested than nonsignificantly congested patients. A similar trend was observed with 90-day mortality although not statistically significant. Conclusions: In patients admitted for acute heart failure, WRF defined as a creatinine increase of ≥0.3 mg/dL was associated with longer length of hospital stay, and worse 30- and 90-day outcomes. However, effects were largely driven by patients who had residual congestion at the time of renal function assessment