324 research outputs found

    Observations of Xyleborus affinis Eichhoff (Coleoptera:Curculionidae:Scolytinae) in Central Michigan

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    Xyleborus affinis Eichhoff colonized wind thrown timber in the moist floodplain habitats of Central Michigan. Single adult females constructed a complex gallery system consisting of phloem–sapwood interface tunnels and sapwood tunnels. An average of 24 progeny adults and a sex ratio of 14 females to 1 male were found in mature galleries after the first of September

    Blueprint for the Dissemination of Evidence-Based Practices in Health Care

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    Proposes strategies for better dissemination of best practices through quality improvement campaigns, including campaigns aligned with adopting organizations' goals, practical implementation tools and guides, and networks to foster learning opportunities

    Cellular mechanisms of myocardial infarct expansion.

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    Infarct expansion is acute regional dilatation and thinning of the infarct zone. There are several possibilities for the mechanism of this alteration in cardiac shape: thinning could be caused by 1) cell rupture, 2) a reduction in the intercellular space, or 3) stretching of myocytes or 4) slippage of groups of myocytes so that less cells are distributed across the wall. To determine the relative contributions of these cellular mechanisms of wall thinning and dilatation, detailed study of transverse histological sections of rat hearts with infarct expansion was performed 1, 2, and 3 days after coronary ligation. The number of cells across the wall was determined in six regions within, adjacent to, and remote from the infarct. Cell counting was performed so that the total number of cells across the wall and the number of cells per unit length (cell density) across the wall were determined. The transmural cell count and the cell density were correlated with the wall thickness in each region. Myocyte cross-sectional areas and sarcomere lengths were also measured. The results from the infarct expansion hearts were compared with those of sham-operated control hearts that had been similarly analyzed. To ensure that mechanisms identified in the rat were applicable to human infarct expansion, five hearts from patients who died within 3 days of infarction and two hearts from patients without coronary disease wer

    Contemporary evidence: baseline data from the D2B Alliance

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    © 2008 Bradley et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

    Perceived Stress After Acute Myocardial Infarction: A Comparison Between Young and Middle-Aged Women Versus Men

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    Objective: The aim of the study was to examine how psychological stress changes over time in young and middle-aged patients after experiencing an acute myocardial infarction (AMI) and whether these changes differ between men and women. Methods: We analyzed data obtained from 2358 women and 1151 men aged 18 to 55 years hospitalized for AMI. Psychological stress was measured using the 14-item Perceived Stress Scale (PSS-14) at initial hospitalization and at 1 month and 12 months after AMI. We used linear mixed-effects models to examine changes in PSS-14 scores over time and sex differences in these changes, while adjusting for patient characteristics and accounting for correlation among repeated observations within patients. Results: Overall, patients' perceived stress decreased over time, especially during the first month after AMI. Women had higher levels of perceived stress than men throughout the 12-month period (difference in PSS-14 score = 3.63, 95% confidence interval = 3.08 to 4.18, p < .001), but they did not differ in how stress changed over time. Adjustment for patient characteristics did not alter the overall pattern of sex difference in changes of perceived stress over time other than attenuating the magnitude of sex difference in PSS-14 score (difference between women and men = 1.74, 95% confidence interval = 1.32 to 2.16, p < .001). The magnitude of sex differences in perceived stress was similar in patients with versus without post-AMI angina, even though patients with angina experienced less improvement in PSS-14 score than those without angina. Conclusions: In young and middle-aged patients with AMI, women reported higher levels of perceived stress than men throughout the first 12 months of recovery. However, women and men had a similar pattern in how perceived stress changed over time

    Acute Reperfusion Therapy in ST-elevation Myocardial Infarction from 1994-2003

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    Background—Appropriate utilization of acute reperfusion therapy is not a national performance measure for ST-elevation myocardial infarction at this time, and the extent of its contemporary use among ideal patients is unknown. Methods—From the National Registry of Myocardial Infarction, we identified 238,291 patients enrolled from June 1994 to May 2003 who were ideally suited for acute reperfusion therapy with fibrinolytic therapy or primary percutaneous coronary intervention. We determined rates of not receiving therapy across 3 time periods (June 1994–May 1997, June 1997–May 2000, June 2000– May 2003) and evaluated factors associated with underutilization. Results—The proportion of ideal patients not receiving acute reperfusion therapy decreased by one-half throughout the past decade (time period 1: 20.6%; time period 2: 11.4%; time period 3: 11.6%; P\u3c0.001). Utilization remained significantly lower in key subgroups in the most recent time period: those without chest pain (OR, 0.29; 95% CI, 0.27–0.32); those presenting 6 to 12 hours after symptom onset (OR, 0.57; 95% CI, 0.52–0.61); those 75 years or older (OR, 0.63 compared with patients \u3c55 years old; 95% CI, 0.58–0.68); women (OR, 0.88; 95% CI, 0.84–0.93); and non-whites (OR, 0.90; 95% CI, 0.83–0.97). Conclusions—Utilization of acute reperfusion therapy in ideal patients has improved over the last decade, but more than 10% remain untreated. Measuring and improving its use in this cohort represents an important opportunity to improve care

    Episodic Occurrence of Field‐Aligned Energetic Ions on the Dayside

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    The tens of kiloelectron volt ions observed in the ring current region at L ~ 3–7 generally have pancake pitch angle distributions, that is, peaked at 90°. However, in this study, by using the Van Allen Probe observations on the dayside, unexpectedly, we have found that about 5% time, protons with energies of ~30 to 50 keV show two distinct populations, having an additional field‐aligned population overlapping with the original pancake population. The newly appearing field‐aligned populations have higher occurrence rates at ~12–16 magnetic local time during geomagnetically active times. In particular, we have studied eight such events in detail and found that the source regions are located around 12 to 18 magnetic local time which coincides with our statistical result. Based on the ionospheric and geosynchronous observations, it is suggested that these energetic ions with field‐aligned pitch angle distributions probably are accelerated near postnoon in association with ionospheric disturbances that are triggered by tail injections.Plain Language SummaryProtons of different sources have different pitch angle distributions (PADs). For example, warm plasma cloak protons, which come directly from the ionosphere, have field‐aligned PADs, while ring current protons that generally originate from tail plasma sheet have pancake‐shaped PADs. In this study, unexpectedly, we have found that about 5% of the time on the dayside, protons of ring current energies show two distinct populations according to their PADs: higher fluxes of field‐aligned populations overlapping with the original pancake populations. The newly appeared field‐aligned populations have higher occurrence rates at ~12–16 magnetic local time during geomagnetically active times. In order to find the mechanism that generates these field‐aligned energetic proton populations, we have studied eight such events in detail by using the low‐altitude DMSP, POES satellites, and the NOAA‐LANL satellite at the geosynchronous orbit. The results imply that these energetic ions with field‐aligned PADs probably are accelerated by ionospheric disturbances that are triggered by tail injections. These results provide evidence of another possibly important source of the ring current ions.Key PointsWe have found that about 5% of the time on the dayside, protons with energies of ~30 to 50 keV have strong field‐aligned PADsThe field‐aligned PADs have higher occurrence rates at ~12‐16 MLT during geomagnetically active timesThese energetic field‐aligned ions possibly are accelerated by ionospheric disturbances triggered by tail injectionsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153687/1/grl60102_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153687/2/grl60102.pd

    Near-Earth injection of MeV electrons associated with intense dipolarization electric fields: Van Allen Probes observations.

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    Substorms generally inject tens to hundreds of keV electrons, but intense substorm electric fields have been shown to inject MeV electrons as well. An intriguing question is whether such MeVelectron injections can populate the outer radiation belt. Here we present observations of a substorm injection of MeV electrons into the inner magnetosphere. In the premidnight sector at L ∌ 5.5, Van Allen Probes (Radiation Belt Storm Probes)-A observed a large dipolarization electric field (50 mV/m) over ∌40 s and a dispersionless injection of electrons up to ∌3 MeV. Pitch angle observations indicated betatron acceleration of MeV electrons at the dipolarization front. Corresponding signals of MeV electron injection were observed at LANL-GEO, THEMIS-D, and GOES at geosynchronous altitude. Through a series of dipolarizations, the injections increased the MeV electron phase space density by 1 order of magnitude in less than 3 h in the outer radiation belt (L &gt; 4.8). Our observations provide evidence that deep injections can supply significant MeV electrons
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