426 research outputs found

    Gas Displacement and Aggregate Stability of Soils

    Get PDF
    When surface soils are dry, O? and N? are adsorbed on the external mineral surfaces. In the process of wetting the soil, water molecules displace the adsorbed O? and N? molecules to the gas phase where they can be measured, as was done in this study. These gases, released from the adsorbed phase, join entrapped air in the gaseous phase as the primary factor disintegrating aggregates when soils are wet quickly. Adsorption of N? and O? occurs on surface soils during hot dry afternoons as the water molecules leave the surface. During cool nights, relative humidities commonly rise above 50%, allowing more strongly adsorbed H?O molecules to displace adsorbed O? and N?. Release of this adsorbed N? and O? causes aggregates wetted by immersion during hot afternoons to be less stable than aggregates of the same soil wetted in the morning

    Registration of GEMS-0001 Maize Germplasm Resistant to Leaf Blade, Leaf Sheath, and Collar Feeding by European Corn Borer

    Get PDF
    This article is from Crop Science 41 (2001): 1651–1652, doi:10.2135/cropsci2001.4151651x.</p

    Atlantic salmon return rate increases with smolt length

    Get PDF
    Recent declines in Atlantic salmon Salmo salar populations are generally attributed to factors in their marine life-phase. However, it is postulated that factors affecting their freshwater life-phase might impact their marine survival, such as the influence of body size. While larger smolts are widely hypothesized to have higher marine survival rates, empirical support remains scant, in part due to inadequate data and ambiguous statistical analyses. Here, we test the influence of smolt body size on marine return rates, a proxy for marine survival, using a 12-year dataset of 3688 smolts tagged with passive integrated transponders in the River Frome, Southern England. State-space models describe the probability of smolts surviving their marine phase to return as 1 sea-winter (1SW) or multi-sea-winter adults as a function of their length, while accounting for imperfect detection and missing data. Models predicted that larger smolts had higher return rates; the most parsimonious model included the effect of length on 1SW return rate. This prediction is concerning, as freshwater juvenile salmon are decreasing in size on the River Frome, and elsewhere. Thus, to maximize adult returns, restoration efforts should focus on freshwater life-stages, and maximize both the number and the size of emigrating smolts

    New early Eocene tapiromorph perissodactyls from the Ghazij Formation of Pakistan, with implications for mammalian biochronology in Asia

    Get PDF
    Early Eocene mammals from Indo-Pakistan have only recently come under study. Here we describe the first tapiromorph perissodactyls from the subcontinent. Gandheralophus minor n. gen. and n. sp. and G. robustus n. sp. are two species of Isectolophidae differing in size and in reduction of the anterior dentition. Gandheralophus is probably derived from a primitive isectolophid such as Orientolophus hengdongensis from the earliest Eocene of China, and may be part of a South Asian lineage that also contains Karagalax from the middle Eocene of Pakistan. Two specimens are referred to a new, unnamed species of Lophialetidae. Finally, a highly diagnostic M3 and a molar fragment are described as the new eomoropid chalicothere Litolophus ghazijensis sp. nov. The perissodactyls described here, in contrast to most other mammalian groups published from the early Eocene of Indo-Pakistan, are most closely related to forms known from East and Central Asia. Tapiromorpha are diverse and biochronologically important in the Eocene there and our results allow the first biochronological correlation between early Eocene mammal faunas in Indo-Pakistan and the rest of Asia. We suggest that the upper Ghazij Formation of Pakistan is best correlated with the middle or late part of the Bumbanian Asian Land-Mammal Age, while the Kuldana and Subathu Formations of Pakistan and India are best correlated with the Arshantan Asian Land-Mammal Age

    Novae Ejecta as Colliding Shells

    Full text link
    Following on our initial absorption-line analysis of fifteen novae spectra we present additional evidence for the existence of two distinct components of novae ejecta having different origins. As argued in Paper I one component is the rapidly expanding gas ejected from the outer layers of the white dwarf by the outburst. The second component is pre-existing outer, more slowly expanding circumbinary gas that represents ejecta from the secondary star or accretion disk. We present measurements of the emission-line widths that show them to be significantly narrower than the broad P Cygni profiles that immediately precede them. The emission profiles of novae in the nebular phase are distinctly rectangular, i.e., strongly suggestive of emission from a relatively thin, roughly spherical shell. We thus interpret novae spectral evolution in terms of the collision between the two components of ejecta, which converts the early absorption spectrum to an emission-line spectrum within weeks of the outburst. The narrow emission widths require the outer circumbinary gas to be much more massive than the white dwarf ejecta, thereby slowing the latter's expansion upon collision. The presence of a large reservoir of circumbinary gas at the time of outburst is suggestive that novae outbursts may sometime be triggered by collapse of gas onto the white dwarf, as occurs for dwarf novae, rather than steady mass transfer through the inner Lagrangian point.Comment: 12 pages, 3 figures; Revised manuscript; Accepted for publication in Astrophysics & Space Scienc

    Trends in hospitalizations and survival of acute decompensated heart failure in four US communities (2005–2014) ARIC study community surveillance

    Get PDF
    BACKGROUND: Community trends of acute decompensated heart failure (ADHF) in diverse populations may differ by race and sex. METHODS: The ARIC study (Atherosclerosis Risk in Communities) sampled heart failure-related hospitalizations (≥55 years of age) in 4 US communities from 2005 to 2014 using International Classification of Diseases, Ninth Revision, Clinical Modification codes. ADHF hospitalizations were validated by standardized physician review and computer algorithm, yielding 40173 events after accounting for sampling design (unweighted n=8746). RESULTS: Of the ADHF hospitalizations, 50% had reduced ejection fraction, and 39% had preserved EF (HFpEF). HF with reduced ejection fraction was more common in black men and white men, whereas HFpEF was most common in white women. Average age-adjusted rates of ADHF were highest in blacks (38.1 per 1000 black men, 30.5 per 1000 black women), with rates differing by HF type and sex. ADHF rates increased over the 10 years (average annual percentage change: black women +4.3%, black men +3.7%, white women +1.9%, white men +2.6%), mostly reflecting more acute HFpEF. Age-adjusted 28-day and 1-year case fatality proportions were ≈10% and 30%, respectively, similar across race-sex groups and HF types. Only blacks showed decreased 1-year mortality over time (average annual percentage change: black women –5.4%, black men –4.6%), with rates differing by HF type (average annual percentage change: black women HFpEF –7.1%, black men HF with reduced ejection fraction –4.7%). CONCLUSIONS: Between 2005 and 2014, trends in ADHF hospitalizations increased in 4 US communities, primarily driven by acute HFpEF. Survival at 1 year was poor regardless of EF but improved over time for black women and black men

    Temporal trends in prevalence and prognostic implications of comorbidities among patients with acute decompensated heart failure: The ARIC study community surveillance

    Get PDF
    Background: Patients with heart failure (HF) have multiple coexisting comorbidities. The temporal trends in the burden of comorbidities and associated risk of mortality among patients with HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF) are not well established. Methods: HF-related hospitalizations were sampled by stratified design from 4 US areas in 2005 to 2014 by the community surveillance component of the ARIC study (Atherosclerosis Risk in Communities). Acute decompensated HF was classified by standardized physician review and a previously validated algorithm. An ejection fraction <50% was considered HFrEF. A total of 15 comorbidities were abstracted from the medical record. Mortality outcomes were ascertained for up to 1-year postadmission by linking hospital records with death files. Results: A total of 5460 hospitalizations (24 937 weighted hospitalizations) classified as acute decompensated HF had available ejection fraction data (53% female, 68% white, 53% HFrEF, 47% HFpEF). The average number of comorbidities was higher for patients with HFpEF versus HFrEF, both for women (5.53 versus 4.94; P<0.0001) and men (5.20 versus 4.82; P<0.0001). There was a significant temporal increase in the overall burden of comorbidities, both for patients with HFpEF (women: 5.17 in 2005-2009 to 5.87 in 2010-2013; men: 4.94 in 2005-2009 and 5.45 in 2010-2013) and HFrEF (women: 4.78 in 2005-2009 to 5.14 in 2010-2013; men: 4.62 in 2005-2009 and 5.06 in 2010-2013; P-trend<0.0001 for all). Higher comorbidity burden was significantly associated with higher adjusted risk of 1-year mortality, with a stronger association noted for HFpEF (hazard ratio [HR] per 1 higher comorbidity, 1.19 [95% CI, 1.14-1.25] versus HFrEF (HR, 1.10 [95% CI, 1.05-1.14]; P for interaction by HF type=0.02). The associated mortality risk per 1 higher comorbidity also increased significantly over time for patients with HFpEF and HFrEF, as well (P for interaction with time=0.002 and 0.02, respectively) Conclusions: The burden of comorbidities among hospitalized patients with acute decompensated HFpEF and HFrEF has increased over time, as has its associated mortality risk. Higher burden of comorbidities is associated with higher risk of mortality, with a stronger association noted among patients with HFpEF versus HFrEF

    Racial Differences and Temporal Obesity Trends in Heart Failure with Preserved Ejection Fraction

    Get PDF
    BACKGROUND/OBJECTIVES: Obesity increases with age, is disproportionately prevalent in black populations, and is associated with heart failure with preserved ejection fraction (HFpEF). An “obesity paradox,” or improved survival with obesity, has been reported in patients with HFpEF. The aim of this study was to examine whether racial differences exist in the temporal trends and outcomes associated with obesity among older patients with HFpEF. DESIGN: Community surveillance of acute decompensated heart failure (ADHF) hospitalizations, sampled by stratified design from 2005 to 2014. SETTING: Atherosclerosis Risk in Communities Study (NC, MS, MD, MN). PARTICIPANTS: A total of 10,147 weighted hospitalizations for ADHF (64% female, 74% white, mean age 77 years), with ejection fraction ≥50%. MEASUREMENTS: ADHF classified by physician review, HFpEF defined by ejection fraction ≥50%. Body mass index (BMI) calculated from weight at hospital discharge. Obesity defined by BMI ≥30 kg/m2, class III obesity by BMI ≥40 kg/m2. RESULTS: When aggregated across 2005–2014, the mean BMI was higher for black compared to white patients (34 vs 30 kg/m2; P <.0001), as was prevalence of obesity (56% vs 43%; P <.0001) and class III obesity (24% vs 13%; P <.0001). Over time, the annual mean BMI and prevalence of class III obesity remained stable for black patients, but steadily increased for white patients, with annual rates statistically differing by race (P-interaction =.04 and P =.03, respectively). For both races, a U-shaped adjusted mortality risk was observed across BMI categories, with the highest risk among patients with a BMI ≥40 kg/m2. CONCLUSION: Black patients were disproportionately burdened by obesity in this decade-long community surveillance of older hospitalized patients with HFpEF. However, temporal increases in mean BMI and class III obesity prevalence among white patients narrowed the racial difference in recent years. For both races, the worst survival was observed with class III obesity. Effective strategies are needed to manage obesity in patients with HFpEF

    Implementation of a transitional care model for stroke: Perspectives from frontline clinicians, administrators, and COMPASS-TC implementation staff

    Get PDF
    Background and Objectives: Stroke is a chronic, complex condition that disproportionally affects older adults. Health systems are evaluating innovative transitional care (TC) models to improve outcomes in these patients. The Comprehensive Post-Acute Stroke Services (COMPASS) Study, a large cluster-randomized pragmatic trial, tested a TC model for patients with stroke or transient ischemic attack discharged home from the hospital. The implementation of COMPASS-TC in complex real-world settings was evaluated to identify successes and challenges with integration into the clinical workflow. Research Design and Methods: We conducted a concurrent process evaluation of COMPASS-TC implementation during the first year of the trial. Qualitative data were collected from 4 sources across 19 intervention hospitals. We analyzed transcripts from 43 conference calls with hospital clinicians, individual and group interviews with leaders and clinicians from 9 hospitals, and 2 interviews with the COMPASS-TC Director of Implementation using iterative thematic analysis. Themes were compared to the domains of the RE-AIM framework. Results: Organizational, individual, and community factors related to Reach, Adoption, and Implementation were identified. Organizational readiness was an additional key factor to successful implementation, in that hospitals that were not "organizationally ready" had more difficulty addressing implementation challenges. Discussion and Implications: Multifaceted TC models are challenging to implement. Facilitators of implementation were organizational commitment and capacity, prioritizing implementation of innovative delivery models to provide comprehensive care, being able to address challenges quickly, implementing systems for tracking patients throughout the intervention, providing clinicians with autonomy and support to address challenges, and adequately resourcing the intervention. Clinical Trial Registration: NCT02588664

    Absolute Proper Motions to B~22.5: IV. Faint, Low Velocity White Dwarfs and the White Dwarf Population Density Law

    Get PDF
    The reduced proper motion diagram (RPMD) for a complete sample of faint stars with high accuracy proper motions in the North Galactic Pole field SA57 is investigated. Eight stars with very large reduced proper motions are identified as faint white dwarf candidates. We discriminate these white dwarf candidates from the several times more numerous QSOs based on proper motion and variability. We discuss the implausibility that these stars could be any kind of survey contaminant. If {\it bona fide} white dwarfs, the eight candidates found here represent a portion of the white dwarf population hitherto uninvestigated by previous surveys by virtue of the faint magnitudes and low proper motions. The newly discovered stars suggest a disk white dwarf scaleheight larger than the values of 250-350 pc typically assumed in assessments of the local white dwarf density. Both a <V/V_{max}> and a more complex maximum likelihood analysis of the spatial distribution of our likely thin disk white dwarfs yield scaleheights of 400-600 pc while at the same time give a reasonable match to the local white dwarf volume density found in other surveys. Our results could have interesting implications for white dwarfs as potential MACHO objects. We can place some direct constraints (albeit weak ones) on the contribution of halo white dwarfs to the dark matter of the Galaxy. Moreover, the elevated scale height that we measure for the thin disk could alter the interpretation of microlensing results to the extent of making white dwarfs untenable as the dominant MACHO contributor. (Abridged)Comment: 38 pages, 5 figures, to appear in April Ap
    corecore