Reproductive success through high pollinator visitation rates despite self incompatibility in an endangered wallflower.

PREMISE OF THE STUDY: Self incompatibility (SI) in rare plants presents a unique challenge-SI protects plants from inbreeding depression, but requires a sufficient number of mates and xenogamous pollination. Does SI persist in an endangered polyploid? Is pollinator visitation sufficient to ensure reproductive success? Is there evidence of inbreeding/outbreeding depression? We characterized the mating system, primary pollinators, pollen limitation, and inbreeding/outbreeding depression in Erysimum teretifolium to guide conservation efforts. METHODS: We compared seed production following self pollination and within- and between-population crosses. Pollen tubes were visualized after self pollinations and between-population pollinations. Pollen limitation was tested in the field. Pollinator observations were quantified using digital video. Inbreeding/outbreeding depression was assessed in progeny from self and outcross pollinations at early and later developmental stages. KEY RESULTS: Self-pollination reduced seed set by 6.5× and quadrupled reproductive failure compared with outcross pollination. Pollen tubes of some self pollinations were arrested at the stigmatic surface. Seed-set data indicated strong SI, and fruit-set data suggested partial SI. Pollinator diversity and visitation rates were high, and there was no evidence of pollen limitation. Inbreeding depression (δ) was weak for early developmental stages and strong for later developmental stages, with no evidence of outbreeding depression. CONCLUSIONS: The rare hexaploid E. teretifolium is largely self incompatible and suffers from late-acting inbreeding depression. Reproductive success in natural populations was accomplished through high pollinator visitation rates consistent with a lack of pollen limitation. Future reproductive health for this species will require large population sizes with sufficient mates and a robust pollinator community.

Characteristics of hospital observation services: a society of cardiovascular patient care survey.

INTRODUCTION: Little is known about the setting in which observation services are provided, or how observation patients are managed in settings such as accredited cardiovascular patient care centers. OBJECTIVE: To describe the characteristics of observation services in accredited Cardiovascular Patient Care hospitals, or those seeking accreditation. METHODS: This is a cross-sectional survey of hospitals either accredited by the Society of Cardiovascular Patient Care, or considering accreditation in 2010. The survey was a web-based free service linked to an e-mail sent to Cardiovascular Patient Care coordinators at the respective institutions. The survey included 17 questions which focused on hospital characteristics and observation services, specifically management, settings, staffing, utilization, and performance data. RESULTS: Of the 789 accredited hospitals, 91 hospitals (11.5%) responded to the survey. Responding hospitals had a median of 250 inpatient beds (interquartile range [IQR] 277), 32.5 emergency department (ED) beds or hall spots, with an average annual ED census of 41,660 (IQR 30,149). These hospitals had an average of 8 (IQR 9) observation unit beds whose median length of stay (LOS) was 19 hours (IQR 8.1), with a discharge rate of 89.1% (IQR 15). There was an average of 1 observation bed to 3.8 ED beds. Observation units were most commonly administered by emergency medicine (48.5%), but staffed by a broad spectrum of specialties. Nonemergency medicine units had longer LOSs, which were not significant. Most common conditions were chest pain and abdominal pain. CONCLUSIONS: Accredited chest pain centers have observation units whose LOSs and discharge rates are comparable to prior studies with utilization patterns that may serve as benchmarks for similar hospitals.

Understanding and controlling nanoporosity formation for improving the stability of bimetallic fuel cell catalysts.

Nanoporosity is a frequently reported phenomenon in bimetallic particle ensembles used as electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells. It is generally considered a favorable characteristic, because it increases the catalytically active surface area. However, the effect of nanoporosity on the intrinsic activity and stability of a nanoparticle electrocatalyst has remained unclear. Here, we present a facile atmosphere-controlled acid leaching technique to control the formation of nanoporosity in Pt-Ni bimetallic nanoparticles. By statistical analysis of particle size, composition, nanoporosity, and atomic-scale core-shell fine structures before and after electrochemical stability test, we uncover that nanoporosity formation in particles larger than ca. 10 nm is intrinsically tied to a drastic dissolution of Ni and, as a result of this, a rapid drop in intrinsic catalytic activity during ORR testing, translating into severe catalyst performance degradation. In contrast, O2-free acid leaching enabled the suppression of nanoporosity resulting in more solid core-shell particle architectures with thin Pt-enriched shells; surprisingly, such particles maintained high intrinsic activity and improved catalytic durability under otherwise identical ORR tests. On the basis of these findings, we suggest that catalytic stability could further improve by controlling the particle size below ca. 10 nm to avoid nanoporosity. Our findings provide an explanation for the degradation of bimetallic particle ensembles and show an easy to implement pathway toward more durable fuel cell cathode catalysts.

Ability of triage decision rules for rapid electrocardiogram to identify patients with suspected ST-elevation myocardial infarction.

BACKGROUND: : The American College of Cardiology/American Heart Association guidelines for ST-elevation myocardial infarction state that an electrocardiogram (ECG) should be performed on patients with suspected acute coronary syndrome upon presentation to the emergency department (ED) within 10 minutes. OBJECTIVE: : To determine how previously published clinical criteria for obtaining an ECG at ED triage perform in a population of patients receiving emergency cardiac catheterization for suspected myocardial infarction. This rule was originally derived by Graff to identify clinical criteria for obtaining an ECG at triage to rapidly identify patients with acute myocardial infarction. The Graff rule was developed in a setting where lytic therapy was the primary reperfusion strategy. A modification proposed by Glickman adds several more criteria in an effort to capture additional patients. We hypothesized that the Graff rule would identify most patients for whom the cardiac catheterization laboratory (CCL) was activated and that the Glickman rule would capture the remaining patients. METHODS: : Three trained physician reviewers retrospectively applied the Graff decision rule to 430 consecutive patients from a database of emergency CCL activations by ED physicians. The Graff rule recommends that patients between the ages of 30 and 49 years received a rapid ECG if they complained of chest pain and those aged 50 years or older received a rapid ECG when they complained of chest pain, shortness of breath, palpitations, weakness, or syncope. The newly developed Glickman rule, which included nausea and vomiting in patients over the age of 80 years, was applied to the patients where the Graff rule was negative. The triage note or earliest medical contact documentation was used to determine whether the patient's complaints would have resulted in a rapid ECG by the decision rule. Each case was reviewed for acute myocardial infarction as defined by high-grade stenosis on the subsequent emergent cardiac catheterization. A single data collection Microsoft Excel spreadsheet was used, and descriptive statistics were performed in Excel and Stata. RESULTS: : Of the 430 CCL activations, 415 (97%; 95% confidence interval, 95%-99%) were identified by the Graff rule. Of the 12 patients who were not identified by the rule, only 2 more were identified by the Glickman criteria. Among patients with confirmed ST-elevation myocardial infarction (79% of CCL activations), the Graff rule was 98% sensitive (95% confidence interval, 96%-99%). CONCLUSIONS: : The Graff ECG triage rule identified almost all patients for whom the CCL was activated. Modification of the rule as proposed by Glickman added very little to the rule's sensitivity, while increasing the number of ECGs required at triage.

State of the art: emergency department observation units.

Hospitals and emergency departments face the challenges of escalating healthcare costs, mismatched resource utilization, concern over avoidable admissions, and hospital and emergency department overcrowding. One approach that has been used by hospitals to address these issues is the use of emergency department observation units. Research in this setting has increased in recent years, leading to a better understanding of the role of these units and their unique benefits. These benefits have been proven for health systems as a whole and for several acute conditions including chest pain, asthma, syncope, transient ischemic attack, atrial fibrillation, heart failure, abdominal pain, and more. Benefits include a decrease in diagnostic uncertainty, lower cost and resource utilization, improved patient satisfaction, and clinical outcomes that are comparable to admitted patients. As more hospitals begin to use observation units, there is a need for further education and research in how to optimize the use of emergency department observation units. The purpose of this article is to provide a general overview of observation units, including advancements and research in this field.