Differential response of barrier island dune grasses to species interactions and burial

Barrier islands are at the forefront of storms and sea-level rise. High disturbance regimes and sediment mobility make these systems sensitive and dynamic. Island foredunes are protective structures against storm-induced overwash that are integrally tied to dune grasses via biogeomorphic feedbacks. Shifts in dune grass dominance could influence dune morphology and susceptibility to overwash, altering island stability. In a glasshouse study, two dune grasses, Ammophila breviligulata and Uniola paniculata, were planted together and subjected to a 20 cm burial to quantify morphological and physiological responses. Burial had positive effects on both plants as indicated by increased electron transport rate and total biomass. Ammophila breviligulata performance declined when planted with U. paniculata. Uniola paniculata was not affected when planted with A. breviligulata but did have higher water use efficiency and nitrogen use efficiency. Planted in mixture, differential reallocation of biomass occurred between species potentially altering resource acquisition further. As U. paniculata migrates into A. breviligulata dominated habitat and A. breviligulata performance diminishes, biotic interactions between these and other species may affect dune formation and community structure. Our study emphasizes the importance of studying biotic interactions alongside naturally occurring abiotic drivers

Functional traits of expanding, thicket-forming shrubs: contrasting strategies between exotic and native species

Woody expansion has been documented for decades in many different systems globally, often yielding vast changes in ecosystem functioning. While causes and consequences of woody expansion have been well documented, few studies have addressed plant functional traits that promote dramatic and rapid expansion in range. Our objectives were to investigate plant functional traits that contribute to the colonization, rapid expansion, and thicket formation of an invasive, N-fixing shrub, Elaeagnus umbellata Thunb. (Elaeagnaceae), and a native, N-fixing shrub Morella cerifera (L.) Small (Myricaceae) and compare to native, sympatric, non-expanding shrub species. Quantified functional traits included morphological (e.g., specific leaf area, leaf area) and physiological characteristics (e.g., electron transport rate, hydraulic conductivity) and were linked to two primary resources: light and water, which directly influence plant growth. Elaeagnus umbellata and M. cerifera rely on different strategies to maximize carbon gain, yet resulting physiological efficiency is similar. Elaeagnus umbellata invests a substantial amount of energy into growth during a short amount of time (i.e., deciduous growing season), using an acquisitive trait strategy to outcompete co-occurring woody species, while M. cerifera is productive year-round and uses a combination of conservative and acquisitive traits to outcompete co-occurring woody species. The majority of quantified functional traits of E. umbellata and several of M. cerifera are indicative of efficient light capture, utilization, and internal water movement. These factors contribute to rapid range expansion and thicket formation by promoting enhanced productivity while simultaneously inhibiting colonization and expansion of co-occurring species. Suites of functional traits are important for expansive success and thicket formation, yet differences in functional traits represent alternative strategies for colonization, rapid expansion, and thicketization

Interaction of Seed Dispersal and Environmental Filtering Affects Woody Encroachment Patterns in Coastal Grassland

Encroachment of woody plants into grasslands has occurred worldwide and includes coastal ecosystems. This conversion process is mediated by seed dispersal patterns, environmental filtering, and biotic interactions. As spatiotemporally heterogeneous, harsh environments, barrier islands present a unique set of challenges for dispersal and establishment. Environmental conditions act as filters on dispersed seeds, thereby influencing encroachment and distribution patterns. Seldom have patterns of propagule dispersal been considered in the context of woody encroachment. We quantified dispersal and post‐dispersal processes of an encroaching woody population of Morella cerifera relative to directional rate of encroachment and observed distribution patterns on an Atlantic coastal barrier island with strong environmental filtering. We analyzed historic foredune elevation as a proxy for reduced interior environmental stress. The dispersal kernel was leptokurtic, a common characteristic of expanding populations, but rate of encroachment has slowed since 2005. Expansion pattern was related to foredune elevation, which limits encroachment below a threshold elevation. This difference between dispersal kernel behavior and encroachment rate is due to limited availability of suitable habitat for Morella and temporal variability in chlorides during the time of germination. Our results demonstrate that processes mediating seeds and seedling success must be accounted for to better understand establishment patterns of encroaching woody plants

Non-invasive Diagnosis of Fatty Liver and Degree of Fatty Liver in Dairy Cows by Digital Analyses of Hepatic Ultrasonograms

The data demonstrate that digital analyses of liver ultrasonograms could diagnose fatty liver and degree of fatty liver (healthy liver, moderate fatty liver, and severe fatty liver with their ranges of 0–8, 8–12, \u3e12% lipids of liver wet weight) with an accuracy of over 90%. Total lipid concentrations could be predicted for liver samples \u3c8% of liver wet weight within 2% of wet weight. Therefore, ultrasound imaging is a reliable, non-invasive technique for determining liver lipid content and for diagnosing fatty liver in early lactation dairy cows to prevent loss of income for dairy farmers

Use of Glucagon to Prevent and Treat Fatty Liver in Transition Dairy Cows

Because of the relationship of fatty liver to increase health problems and decreased productive and reproductive performance, scientists can improve the profitability of dairy farmers by developing nutritional and management technologies for preventing and treating fatty liver. Our research group has demonstrated that glucagon shows much promise for use in preventing and treating fatty liver in transition cows. Moreover, we have data to indicate that ultrasound technology can be used to estimate the incidence of fatty liver within a dairy herd. The development of a slow-release form of glucagon would seem necessary before adoption of our proposed glucagon technology is adopted by the dairy industry

Spectroscopic Survey of G and K Dwarfs in the Hipparcos Catalog. I. Comparison between the Hipparcos and Photometric Parallaxes

The tension between the Hipparcos parallax of the Pleiades and other independent distance estimates continues even after the new reduction of the Hipparcos astrometric data and the development of a new geometric distance measurement for the cluster. A short Pleiades distance from the Hipparcos parallax predicts a number of stars in the solar neighborhood that are sub-luminous at a given photospheric abundance. We test this hypothesis using the spectroscopic abundances for a subset of stars in the Hipparcos catalog, which occupy the same region as the Pleiades in the color–magnitude diagram. We derive stellar parameters for 170 nearby G- and K-type field dwarfs in the Hipparcos catalog based on high-resolution spectra obtained using KPNO 4 m echelle spectrograph. Our analysis shows that, when the Hipparcos parallaxes are adopted, most of our sample stars follow empirical color–magnitude relations. A small fraction of stars are too faint compared to main-sequence fitting relations by ΔM_V ≳ 0.3 mag, but the differences are marginal at a 2σ level, partly due to relatively large parallax errors. On the other hand, we find that the photometric distances of stars showing signatures of youth as determined from lithium absorption line strengths and R_(HK)^' chromospheric activity indices are consistent with the Hipparcos parallaxes. Our result is contradictory to a suggestion that the Pleiades distance from main-sequence fitting is significantly altered by stellar activity and/or the young age of its stars, and provides an additional supporting evidence for the long-distance scale of the Pleiades

PENGARUH METODE EKSPERIMEN DAN METODE DEMONSTRASI TERHADAP PRESTASI BELAJAR FISIKA POKOK BAHASAN LISTRIK DINAMIS

Penelitian ini secara deskriptif bertujuan untuk mengetahui kecendrungan prestasi belajar fisika pokok bahasan listrik dinamis yang diajar menggunakan metode Eksperimen, metode demonstrasi dan metode pembelajaran Konvebsional. Secara komparatif untuk mengetahui perbedaan prestasi belajar fisika pokok bahasan listrik dinamis antara yang diajar menggunakan metode Eksperimen, metode Demonstrasi dan metode Konvensional. Jenis penelitian ini adalah Quasi Eksperimen. Populasi dalam penelitian adalah seluruh siswa kelas X yang terdiri dari 7 kelas sejumlah 217 siswa. Sampel diambil dengan teknik random sampling. Kemampuan awal diperoleh dari nilai pre-test. Data prestasi hasil belajar dikumpulkan dengan tes pilihan ganda. Teknik analisis data dengan menggunakan uji Anava satu jalur, setelah dilakukan uji persyaratan yang meliputi uji normalitas sebaran dan uji homogenitas varian. Hasil penelitian menunjukkan bahwa ada perbedaan yang sangat signifikan prestasi belajar fisika antara yang diajar menggunakan metode Eksperimen, metode Demonstrasi dan yang diajar menggunakan metode Konvebsional

Climate Quality Broadband and Narrowband Solar Reflected Radiance Calibration Between Sensors in Orbit

vAs the potential impacts of global climate change become more clear [1], the need to determine the accuracy of climate prediction over decade-to-century time scales has become an urgent and critical challenge. The most critical tests of climate model predictions will occur using observations of decadal changes in climate forcing, response, and feedback variables. Many of these key climate variables are observed by remotely sensing the global distribution of reflected solar spectral and broadband radiance. These "reflected solar" variables include aerosols, clouds, radiative fluxes, snow, ice, vegetation, ocean color, and land cover. Achieving sufficient satellite instrument accuracy, stability, and overlap to rigorously observe decadal change signals has proven very difficult in most cases and has not yet been achieved in others [2]. One of the earliest efforts to make climate quality observations was for Earth Radiation Budget: Nimbus 6/7 in the late 1970s, ERBE in the 1980s/90s, and CERES in 2000s are examples of the most complete global records. The recent CERES data products have carried out the most extensive intercomparisons because if the need to merge data from up to 11 instruments (CERES, MODIS, geostationary imagers) on 7 spacecraft (Terra, Aqua, and 5 geostationary) for any given month. In order to achieve climate calibration for cloud feedbacks, the radiative effect of clear-sky, all-sky, and cloud radiative effect must all be made with very high stability and accuracy. For shortwave solar reflected flux, even the 1% CERES broadband absolute accuracy (1-sigma confidence bound) is not sufficient to allow gaps in the radiation record for decadal climate change. Typical absolute accuracy for the best narrowband sensors like SeaWiFS, MISR, and MODIS range from 2 to 4% (1-sigma). IPCC greenhouse gas radiative forcing is approx. 0.6 W/sq m per decade or 0.6% of the global mean shortwave reflected flux, so that a 50% cloud feedback would change the global reflected flux by approx. 0.3 W/sq m or 0.3% per decade in broadband SW calibration change. Recent results comparing CERES reflected flux changes with MODIS, MISR, and SeaWiFS narrowband changes concluded that only SeaWiFS and CERES were approaching sufficient stability in calibration for decadal climate change [3]. Results using deep convective clouds in the optically thick limit as a stability target may prove very effective for improving past data sets like ISCCP. Results for intercalibration of geostationary imagers to CERES using an entire month of regional nearly coincident data demonstrates new approaches to constraining the calibration of current geostationary imagers. The new Decadal Survey Mission CLARREO is examining future approaches to a "NIST-in-Orbit" approach of very high absolute accuracy reference radiometers that cover the full solar and infrared spectrum at high spectral resolution but at low spatial resolution. Sampling studies have shown that a precessing CLARREO mission could calibrate other geo and leo reflected solar radiation and thermal infrared sensors

Biventricular adaptation to volume overload in mice with aortic regurgitation

<p>Abstract</p> <p>Background</p> <p>Aortic valve regurgitation is usually caused by impaired coaptation of the aortic valve cusps during diastole. Hypercholesterolemia produces aortic valve lipid deposition, fibrosis, and calcification in both mice and humans, which could impair coaptation of cusps. However, a link between hypercholesterolemia and aortic regurgitation has not been established in either species. The purpose of this study was to ascertain the prevalence of aortic regurgitation in hypercholesterolemic mice and to determine its impact on the left and right ventricles.</p> <p>Methods and Results</p> <p>Eighty <it>Ldlr</it>^-/-/<it>Apob</it>^100/100/<it>Mttp</it>^fl/fl/Mx1Cre^+/+("Reversa") hypercholesterolemic mice and 40 control mice were screened for aortic regurgitation (AR) with magnetic resonance imaging at age 7.5 months. The prevalence of AR was 40% in Reversa mice, with moderate or severe regurgitation (AR⁺) in 19% of mice. In control mice, AR prevalence was 13% (p = 0.004 <it>vs</it>. Reversa), and was invariably trace or mild in severity. In-depth evaluation of cardiac response to volume overload was performed in 12 AR-positive and 12 AR-negative Reversa mice. Regurgitant fraction was 0.34 ± 0.04 in AR-positive <it>vs</it>. 0.02 ± 0.01 in AR-negative (mean ± SE; p < 0.001). AR-positive mice had significantly increased left ventricular end-diastolic volume and mass and reduced ejection fraction in both ventricles. When left ventricular ejection fraction fell below 0.60 in AR-positive (<it>n </it>= 7) mice, remodeling occurred and right ventricular systolic function progressively worsened.</p> <p>Conclusion</p> <p>Hypercholesterolemia causes aortic valve regurgitation with moderate prevalence in mice. When present, aortic valve regurgitation causes volume overload and pathological remodeling of both ventricles.</p