360 research outputs found
Interaction potentials, spectroscopy and transport properties of C+(2PJ) and C+(4PJ) with helium
We calculate accurate interatomic potentials for the interaction of a singly-charged carbon cation with a helium atom. We employ the RCCSD(T) method, and basis sets of quadruple-zeta and quintuple-zeta quality; each point is counterpoise corrected and extrapolated to the basis set limit. We consider the two lowest C+(2P) and C+(4P) electronic states of the carbon cation, and calculate the interatomic potentials for the terms that arise from these: 2-PI and 2-SIG+, and 4-PI and 4-SIG- , respectively. We additionally calculate the interatomic potentials for the respective spin-orbit levels, and examine the effect on the spectroscopic parameters. Finally, we employ each set of potentials to calculate transport coefficients, and compare these to available data. Critical comments are made in the cases where there are discrepancies between the calculated values and measured data
Short-term post-harvest stress that affects profiles of volatile organic compounds and gene expression in rocket salad during early post-harvest senescence
Once harvested, leaves undergo a process of senescence which shares some features with developmental senescence. These include changes in gene expression, metabolites, and loss of photosynthetic capacity. Of particular interest in fresh produce are changes in nutrient content and the aroma, which is dependent on the profile of volatile organic compounds (VOCs). Leafy salads are subjected to multiple stresses during and shortly after harvest, including mechanical damage, storage or transport under different temperature regimes, and low light. These are thought to impact on later shelf life performance by altering the progress of post-harvest senescence. Short term stresses in the first 24 h after harvest were simulated in wild rocket (Diplotaxis tenuifolia). These included dark (ambient temperature), dark and wounding (ambient temperature), and storage at 4 \ub0C in darkness. The effects of stresses were monitored immediately afterwards and after one week of storage at 10 \ub0C. Expression changes in two NAC transcription factors (orthologues of ANAC059 and ANAC019), and a gene involved in isothiocyanate production (thiocyanate methyltransferase, TMT) were evident immediately after stress treatments with some expression changes persisting following storage. Vitamin C loss and microbial growth on leaves were also affected by stress treatments. VOC profiles were differentially affected by stress treatments and the storage period. Overall, short term post-harvest stresses affected multiple aspects of rocket leaf senescence during chilled storage even after a week. However, different stress combinations elicited different responses
Mechanical Mitral Valve Replacement: A Multicenter Study of Outcomes with Use of 15- to 17-mm Prostheses
Background: The aim of this study was to evaluate early and mid-term outcomes (mortality and prosthetic valve reintervention) after mitral valve replacement with 15- to 17-mm mechanical pr
Speaking of trade: Its effect on agriculture
This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu
Phenomenology of the Lense-Thirring effect in the Solar System
Recent years have seen increasing efforts to directly measure some aspects of
the general relativistic gravitomagnetic interaction in several astronomical
scenarios in the solar system. After briefly overviewing the concept of
gravitomagnetism from a theoretical point of view, we review the performed or
proposed attempts to detect the Lense-Thirring effect affecting the orbital
motions of natural and artificial bodies in the gravitational fields of the
Sun, Earth, Mars and Jupiter. In particular, we will focus on the evaluation of
the impact of several sources of systematic uncertainties of dynamical origin
to realistically elucidate the present and future perspectives in directly
measuring such an elusive relativistic effect.Comment: LaTex, 51 pages, 14 figures, 22 tables. Invited review, to appear in
Astrophysics and Space Science (ApSS). Some uncited references in the text
now correctly quoted. One reference added. A footnote adde
EXPLORE: A Prospective, Multinational, Natural History Study of Patients with Acute Hepatic Porphyria with Recurrent Attacks
BACKGROUND AND AIMS: Acute hepatic porphyria
comprises a group of rare genetic diseases caused by mutations in genes involved in heme biosynthesis. Patients can
experience acute neurovisceral attacks, debilitating chronic
symptoms, and long-term complications. There is a lack of
multinational, prospective data characterizing the disease and
current treatment practices in severely affected patients.
APPROACH AND RESULTS: EXPLORE is a prospective,
multinational, natural history study characterizing disease activity and clinical management in patients with acute hepatic
porphyria who experience recurrent attacks. Eligible patients
had a confirmed acute hepatic porphyria diagnosis and had
experienced ≥3 attacks in the prior 12 months or were receiving prophylactic treatment. A total of 112 patients were enrolled and followed for at least 6 months. In the 12 months
before the study, patients reported a median (range) of 6
(0-52) acute attacks, with 52 (46%) patients receiving hemin
prophylaxis. Chronic symptoms were reported by 73 (65%)
patients, with 52 (46%) patients experiencing these daily.
During the study, 98 (88%) patients experienced a total of
483 attacks, 77% of which required treatment at a health
care facility and/or hemin administration (median [range] annualized attack rate 2.0 [0.0-37.0]). Elevated levels of hepatic
δ-aminolevulinic acid synthase 1 messenger ribonucleic acid levels, δ-aminolevulinic acid, and porphobilinogen compared with
the upper limit of normal in healthy individuals were observed
at baseline and increased further during attacks. Patients had
impaired quality of life and increased health care utilization.
CONCLUSIONS: Patients experienced attacks often requiring treatment in a health care facility and/or with hemin, as
well as chronic symptoms that adversely influenced day-to-day
functioning. In this patient group, the high disease burden
and diminished quality of life highlight the need for novel
therapies. (Hepatology 2020;71:1546-1558)
EXPLORE: A prospective, multinational natural history study of patients with acute hepatic porphyria with recurrent attacks
BACKGROUND AND AIMS: Acute hepatic porphyria
comprises a group of rare genetic diseases caused by mutations in genes involved in heme biosynthesis. Patients can
experience acute neurovisceral attacks, debilitating chronic
symptoms, and long-term complications. There is a lack of
multinational, prospective data characterizing the disease and
current treatment practices in severely affected patients.
APPROACH AND RESULTS: EXPLORE is a prospective,
multinational, natural history study characterizing disease activity and clinical management in patients with acute hepatic
porphyria who experience recurrent attacks. Eligible patients
had a confirmed acute hepatic porphyria diagnosis and had
experienced ≥3 attacks in the prior 12 months or were receiving prophylactic treatment. A total of 112 patients were enrolled and followed for at least 6 months. In the 12 months
before the study, patients reported a median (range) of 6
(0-52) acute attacks, with 52 (46%) patients receiving hemin
prophylaxis. Chronic symptoms were reported by 73 (65%)
patients, with 52 (46%) patients experiencing these daily.
During the study, 98 (88%) patients experienced a total of
483 attacks, 77% of which required treatment at a health
care facility and/or hemin administration (median [range] annualized attack rate 2.0 [0.0-37.0]). Elevated levels of hepatic
δ-aminolevulinic acid synthase 1 messenger ribonucleic acid levels, δ-aminolevulinic acid, and porphobilinogen compared with
the upper limit of normal in healthy individuals were observed
at baseline and increased further during attacks. Patients had
impaired quality of life and increased health care utilization.
CONCLUSIONS: Patients experienced attacks often requiring treatment in a health care facility and/or with hemin, as
well as chronic symptoms that adversely influenced day-to-day
functioning. In this patient group, the high disease burden
and diminished quality of life highlight the need for novel
therapies. (Hepatology 2020;71:1546-1558)
Macrophyte abundance in Waquoit Bay : effects of land-derived nitrogen loads on seasonal and multi-year biomass patterns
Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Estuaries and Coasts 31 (2008): 532-541, doi:10.1007/s12237-008-9039-6.Anthropogenic inputs of nutrients to coastal waters have rapidly restructured coastal ecosystems. To examine the response of macrophyte communities to land-derived nitrogen loading, we measured macrophyte biomass monthly for six years in three estuaries subject to different nitrogen loads owing to different land uses on the watersheds. The set of estuaries sampled had nitrogen loads over the broad range of 12 to 601 kg N ha-1 y-1. Macrophyte biomass increased as nitrogen loads increased, but the response of individual taxa varied. Specifically, biomass of Cladophora vagabunda and Gracilaria tikvahiae increased significantly as nitrogen loads increased. The biomass of other macroalgal taxa tended to decrease with increasing load, and the relative proportion of these taxa to total macrophyte biomass also decreased. The seagrass, Zostera marina, disappeared from the higher loaded estuaries, but remained abundant in the estuary with the lowest load. Seasonal changes in macroalgal standing stock were also affected by nitrogen load, with larger fluctuations in biomass across the year and higher minimum biomass of macroalgae in the higher loaded estuaries. There were no significant changes in macrophyte biomass over the six years of this study, but there was a slight trend of increasing macroalgal biomass in the latter years. Macroalgal biomass was not related to irradiance or temperature, but Z. marina biomass was highest during the summer months when light and temperatures peak. Irradiance might, however, be a secondary limiting factor controlling macroalgal biomass in the higher loaded estuaries by restricting the depth of the macroalgal canopy. The relationship between the bloom-forming macroalgal species, C. vagabunda and G. tikvahiae, and nitrogen loads suggested a strong connection between development on watersheds and macroalgal blooms and loss of seagrasses. The influence of watershed land uses largely overwhelmed seasonal and inter-annual differences in standing stock of macrophytes in these temperate estuaries.This research was supported by the National Oceanic and Atmospheric Administration (NOAA), Cooperative Institute for Coastal and Estuarine Environmental Technologies (CICEET-UNH#99-304, NOAA NA87OR512), NOAA National Estuarine Research Reserve Graduate Research Fellowship NERRS GRF, #NA77OR0228), and an Environmental Protection Agency (EPA) STAR Fellowship for Graduate Environmental Study (U-915335-01-0) awarded to J. Hauxwell. S. Fox was supported by a NOAA NERRS GRF (#NA03NOS4200132) and an EPA STAR Graduate Research Fellowship. We also thank the Quebec-Labrador Foundation Atlantic Center for the Environment's Sounds Conservancy Program and the Boston University Ablon/Bay Committee for their awarding research funds
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