A Theory of Mental Frameworks

Problem-solving skills are highly valued in modern society and are often touted as core elements of school mission statements, desirable traits for job applicants, and as some of the most complex thinking that the brain is capable of executing. While learning to problem-solve is a goal of education, and many strategies, methodologies, and activities exist to help teachers guide the development of these skills, there are few formal curriculum structures or broader frameworks that guide teachers toward the achievement of this educational objective. Problem-solving skills have been called "higher order cognitive functions" in cognitive neuroscience as they involve multiple complex networks in the brain, rely on constant rehearsal, and often take years to form. Children of all ages employ problem solving, from a newborn seeking out food to children learning in school settings, or adults tackling real-world conflicts. These skills are usually considered the end product of a good education when in fact, in order to be developed they comprise an ongoing process of learning. "Ways of thinking" have been studied by philosophers and neuroscientists alike, to pinpoint cognitive preferences for problem solving approaches that develop from exposure to distinct models, derived from and resulting in certain heuristics used by learners. This new theory paper suggests a novel understanding of the brain's approach to problem solving that structures existing problem-solving frameworks into an organized design. The authors surveyed problem-solving frameworks from business administration, design, engineering, philosophy, psychology, education, neuroscience and other learning sciences to assess their differences and similarities. This review lead to an appreciation that different problem-solving frameworks from different fields respond more or less accurately and efficiently depending on the kinds of problems being tackled, leading to our conclusion that a wider range of frameworks may help individuals approach more varied problems across fields, and that such frameworks can be organized in school curriculum. This paper proposes that explicit instruction of "mental frameworks" may help organize and formalize the instruction of thinking skills that underpin problem-solving-and by extension-that the more such models a person learns, the more tools they will have for future complex problem-solving. To begin, this paper explains the theoretical underpinnings of the mental frameworks concept, then explores some existing mental frameworks which are applicable to all age groups and subject areas. The paper concludes with a list of five limitations to this proposal and pairs them with counter-balancing benefits.

Allometry and stoichiometry of unicellular, colonial and multicellular phytoplankton.

Phytoplankton life forms, including unicells, colonies, pseudocolonies, and multicellular organisms, span a huge size range. The smallest unicells are less than 1 microm3 (e.g. cyanobacteria), while large unicellular diatoms may attain 10(9) microm3, being visible to the naked eye. Phytoplankton includes chemo-organotrophic unicells, colonies and multicellular organisms that depend on symbionts or kleptoplastids for their capacity to photosynthesize. Analyses of physical (transport within cells, diffusion boundary layers, package effect, turgor, and vertical movements) and biotic (grazing, viruses and other parasitoids) factors indicate potential ecological constraints and opportunities that differ among the life forms. There are also variations among life forms in elemental stoichiometry and in allometric relations between biovolume and specific growth. While many of these factors probably have ecological and evolutionary significance, work is needed to establish those that are most important, warranting explicit description in models. Other factors setting limitations on growth rate (selecting slow-growing species) await elucidation.

Prevalence and repair of intraoperatively diagnosed patent foramen ovale and association with perioperative outcomes and long-term survival.

CONTEXT: A recent survey suggested that cardiothoracic surgeons may alter planned procedures to repair incidentally discovered patent foramen ovale (PFO). How frequently this occurs and the impact on outcomes remain unknown. OBJECTIVE: To measure the frequency of incidentally discovered PFO closure during cardiothoracic surgery and determine its perioperative and long-term impact. DESIGN, SETTING, AND PATIENTS: We reviewed the intraoperative transesophageal echocardiograms of 13,092 patients without prior diagnosis of PFO or atrial septal defect undergoing surgery at the Cleveland Clinic, Cleveland, Ohio, from 1995 through 2006. Postoperative outcomes were prospectively collected until discharge. MAIN OUTCOME MEASURES: All-cause hospital mortality and stroke were predetermined primary outcomes; length of hospital stay, length of intensive care unit stay, and time on cardiopulmonary bypass were secondary outcomes. RESULTS: Intraoperative PFO was diagnosed in 2277 patients in the study population (17%), and risk factors for stroke were similar in patients with and without PFO. After propensity matching was performed with the comparator groups, patients with PFO demonstrated similar rates of in-hospital death (3.4% vs 2.6%, P = .11) and postoperative stroke (2.3% vs 2.3%, P = .84). Surgical closure was performed in 639 PFO patients (28%), and surgeons were more likely to close defects in patients who were younger (mean [SD] age, 61.1 [14] vs 64.4 [13] years; P < .001), were undergoing mitral or tricuspid valve surgery (51% vs 32%, P < .001), or had history of transient ischemic attack or stroke (16% vs 10%, P < .001). Patients with repaired PFO demonstrated a 2.47-times greater odds (95% confidence interval, 1.02-6.00) of having a postoperative stroke compared with those with unrepaired PFO (2.8% vs 1.2%, P = .04). Long-term analysis demonstrated that PFO repair was associated with no survival difference (P = .12). CONCLUSIONS: Incidental PFO is common in patients undergoing cardiothoracic surgery but is not associated with increased perioperative morbidity or mortality. Surgical closure appears unrelated to long-term survival and may increase postoperative stroke risk.

Comparison of procedural complications with versus without interventional cardiology fellows-in-training during contemporary percutaneous coronary intervention.

Despite increasing complexity of contemporary procedures at tertiary care hospitals, the relationship between interventional cardiology fellows-in-training (ICFITs) and complications of percutaneous coronary intervention (PCI) has not been reported. We compiled logbooks of 6 ICFITs at an academic hospital and evaluated patient and procedural characteristics of PCIs performed with and without presence of an ICFIT. The primary end point was the composite of all in-hospital PCI complications defined by the American College of Cardiology's National Cardiovascular Data Registry: (1) catheterization laboratory events such as no-reflow and dissection/perforation, (2) general clinical events such as stroke or cardiogenic shock, (3) vascular and bleeding complications, and (4) miscellaneous complications such as peak troponin or creatinine levels. Logistic regression adjusted for differences in measured confounders between patients treated with and without presence of an ICFIT. All analyses were repeated after excluding PCI for ST-elevation myocardial infarction. Of 2,605 PCI procedures at the academic hospital between July 2007 and April 2010, an ICFIT was present for 1,638 procedures (63%). Despite having worse clinical and procedural characteristics, patients in the ICFIT group experienced similar rates of the composite end point (12.9% vs 14.5% without ICFIT, p = 0.27). Longer mean fluoroscopy times and greater number of stents were noted in the ICFIT group; however, hospital length of stay was shorter and no individual adverse events were increased in the ICFIT procedures. Presence of an ICFIT remained unrelated to the composite end point after multivariable adjustment (odds ratio 0.92, 95% confidence interval 0.71 to 1.20; p = 0.53), and findings were similar after excluding PCI for ST-elevation myocardial infarction. In conclusion, in contemporary practice at a large academic medical center, PCI complication rates were not adversely affected by the presence of an ICFIT.

Comparison of bleeding complications using arterial closure device versus manual compression by propensity matching in patients undergoing percutaneous coronary intervention.

Arterial closure devices (ACDs) provide immediate hemostasis, improve comfort, and allow early ambulation after percutaneous coronary intervention (PCI). The aim of this study was to evaluate ACD utilization and post-PCI major bleeding in an unselected cohort. Patients receiving ACDs were propensity matched to those with manual compression to evaluate a primary end point of National Cardiovascular Data Registry (NCDR) major bleeding and a secondary end point of major bleeding stratified by previously developed NCDR bleeding risk categories. Bleeding events that required transfusion, prolonged hospital stays, and/or decreases in hemoglobin ≥3.0 g/dl were included. Length of stay, defined as days after PCI until discharge, was also evaluated. Secondary analysis of bleeding and complication rates between ACD types (suture vs collagen plug) was performed. Five thousand four hundred twenty-one patients underwent PCI, and 2,324 patients (43%) were included in the final propensity matching: 1,162 with ACDs and 1,162 manual compression patients. Major bleeding was reduced in ACD patients compared to those with manual compression (2.4% vs 5.2%, p <0.001), and NCDR high-risk patients receiving ACDs had the greatest reduction in major bleeds (3.1% vs 10.3%, p <0.001). Length of stay (1.9 ± 1.9 vs 2.3 ± 5.3 days, p = 0.007) and pseudoaneurysms (0.3% vs 1.1%, p = 0.028) were decreased in ACD patients. Suture-based devices revealed a lower composite event rate than collagen-plug ACDs (1.4% vs 3.4%, p = 0.048). In conclusion, ACD use is associated with reductions in NCDR major bleeding, length of stay, and pseudoaneurysms in PCI patients.

Relation of brain natriuretic peptide level to extent of left ventricular scarring in patients with chronic heart failure secondary to ischemic cardiomyopathy.

Multiple factors influence brain natriuretic peptide (BNP) release in patients with heart failure. We hypothesized that extensive myocardial scarring could result in an attenuated BNP response. A total of 115 patients with New York Heart Association class III chronic heart failure and ischemic cardiomyopathy were evaluated for ischemia, hibernation, and myocardial scarring by dipyridamole-rubidium-positron emission tomographic scanning with fluorine-18, 2-fluoro-2-deoxyyglucose. Plasma BNP levels were determined within 2 weeks of the study. Left ventricular dimension and function were evaluated by echocardiography. Patients were categorized as having <33% myocardial scar (n=67) or>or=33% myocardial scar (n=48). BNP measurements were correlated with amount of myocardial scarring. Compared with patients with less scar, those with >or=33% scar had lower BNP levels (mean 317+/-364 vs 635+/-852 pg/ml, median 212 vs 357, p=0.016). Using multiple regression analysis, presence of scarring was associated with decreased BNP response (p=0.022). Further, patients with <33% scar in whom a higher BNP level was noted had more ischemia (51% vs 27%, p=0.01) and greater myocardial hibernation (22+/-14% vs 12+/-7%, p=0.02) compared with patients with >or=33% scar. In conclusion, in patients with chronic heart failure, a decreased BNP response indicated extensive myocardial scarring.