1,618 research outputs found
The effect of carbon and nutrient loading during nursery culture on the growth of black spruce seedlings: a six-year field study
Abstract We tested the effects of exponential nutrient loading and springtime carbon loading during nursery culture on the field performance of black spruce (Picea mariana (Mill.) B.S.P.). Seedlings were grown from seed with a conventional, fixed dose fertilizer (10 mg N seedling Ă1 ) or an exponential nutrient loading regime (75 mg N seedling Ă1 ). The following spring, seedlings were exposed for two weeks to either ambient (370 ppm) or elevated levels of CO 2 (800 ppm) and then planted in the field; seedling growth was followed for the next six years. Exponential nutrient loading increased seedling height, stem diameter and leader growth, with the largest increases in height and leader length occurring in the first three years after outplanting. Carbon loading increased seedling height and leader length, but only in seedlings that had been exponentially nutrient loaded. A combination of carbon and nutrient loading increased shoot height 26%, stem diameter 37% and leader length 40% over trees that received neither treatment. These results demonstrate that the growth enhancement seen under exponential nutrient loading is maintained under field conditions for at least six years. Carbon loading just before outplanting was a useful supplement to nutrient loading, but was ineffective in the absence of nutrient loading
Components of Antineutrino Emission in Nuclear Reactor
New scattering experiments aimed for sensitive searches of
the magnetic moment and projects to explore small mixing angle
oscillations at reactors call for a better understanding of the reactor
antineutrino spectrum. Here we consider six components, which contribute to the
total spectrum generated in nuclear reactor. They are: beta
decay of the fission fragments of U, Pu, U and
Pu, decay of beta-emitters produced as a result of neutron capture in
U and also due to neutron capture in accumulated fission fragments
which perturbs the spectrum. For antineutrino energies less than 3.5 MeV we
tabulate evolution of spectra corresponding to each of the four
fissile isotopes vs fuel irradiation time and their decay after the irradiation
is stopped and also estimate relevant uncertainties. Small corrections to the
ILL spectra are considered.Comment: LaTex 8 pages, 2 ps figure
Long-term evolution and coupling of the boundary layers in the Stratus Deck Regions of the eastern Pacific (STRATUS)
A surface mooring was deployed in the eastern tropical Pacific west of northern Chile from the R/V Melville as part of the Eastern Pacific Investigation of Climate (EPIC). EPIC is a CLIVAR study with the goal of investigating links between sea surface temperature variability in the eastern tropical Pacific and climate over the American continents. Important to that goal is an understanding of the role of clouds in the eastern Pacific in modulating atmosphere-ocean coupling. The mooring was deployed near 20°S 85°W, at a location near the western edge of the stratocumulus cloud deck found west of Peru and Chile. This deployment started a three-year occupation of that site by a WHOI surface mooring in order to collect accurate time series of surface forcing and upper ocean variability. The surface mooring was deployed by the Upper Ocean Processes Group of the Woods Hole Oceanographic Institution (WHOI). In collaboration with investigators from the University of Concepcion, Concepcion, Chile, an XBT section was made on the way out to the mooring from Arica, Chile, and an XBT and CTD section was made on the way into Arica.
The buoy was equipped with meteorological instrumentation, including two Improved METeorological (IMET) systems. The mooring also carried Vector Measuring Current Meters, single-temperature recorders, and conductivity and temperature recorders located in the upper meters of the mooring line. In addition to the instrumentation noted above, a variety of other instruments, including an acoustic current meter, an acoustic doppler current profiler, a bio-optical instrument package, and an acoustic rain guage, were deployed.
This report describes, in a general manner, the work that took place and the data collected during the Cook 2 cruise aboard the R/V Melville. The surface mooring deployed during this cruise will be recovered and re-deployed after approximately 12 months and again after 24 months, with a final recovery planned for 36 months after the first setting. Details of the mooring design and preliminary data from the XBT and CTD sections are included.Funding was provided by the National Oceanic and Atmospheric Administration
under grant number NA96GP0429
Current Trends on MA Translation Courses in the UK: Changing Assessment Practices on Core Translation Modules
Assessment underpins all forms of translator training and is an essential element of any teaching and learning process. By looking at university assessment practices, we can gain an insight into current understandings about the nature of translation practice and what issues are foregrounded in translator education. This paper presents the findings of the second stage of our research into assessment practices on core translation modules of MA Translation courses offered in the UK, and follows on from a preliminary case study conducted at the University of Westminster in 2015 and 2016 with MA Translation tutors and students (n=16; n=53). The research presented in this paper was carried out via documentary research into all universities offering MA Translation courses (n=27) and via a survey which asked a representative of each UK university to fill out a questionnaire. The questionnaire was completed by 55% of universities (n=15). The areas explored include universities' learning outcomes, assessment instruments and criteria. In the light of the data gathered, our study aims to discover if and to what extent current assessment practices on the core translation modules reflect the competence-based understandings of the translation process and have adopted new forms of assessment
Variants in PCSK7, PNPLA3 and TM6SF2 are risk factors for the development of cirrhosis in hereditary haemochromatosis
BACKGROUND: Cirrhosis develops in <10% of individuals homozygous for the C282Y variant in the homeostatic iron regulator (HFE) gene. Carriage of PCSK7:rs236918 is associated with an increased risk of cirrhosis in this population. AIM: To determine if genetic variants significantly associated with the risk of alcohol- and NAFLD-related cirrhosis also modulate the cirrhosis risk in C282Y homozygotes. METHODS: Variants in PCSK7, PNPLA3, TM6SF2, MBOAT7 and HSD17B13 were genotyped in 1319 C282Y homozygotes, from six European countries, of whom 171 (13.0%) had cirrhosis. Genotypic and allelic associations with the risk for developing cirrhosis were assessed, adjusting for age and sex. Fixed effects meta-analyses of the adjusted summary data for each country were performed. Post hoc association testing was undertaken in the 131 (76.6%) cases and 299 (26.0%) controls with available liver histology. RESULTS: Significant associations were observed between PCSK7:rs236918 (ORÂ =Â 1.52 [95% CI 1.06-2.19]; PÂ =Â 0.022; I2 Â =Â 0%); PNPLA3:rs738409 (ORÂ =Â 1.60 [95% CI 1.22-2.11]; PÂ =Â 7.37Â ĂÂ 10-4 ; I2 Â =Â 45.5%) and TM6SF2:rs58542926 (ORÂ =Â 1.94 [95% CI 1.28-2.95]; PÂ =Â 1.86Â ĂÂ 10-3 ; I2 Â =Â 0%) and the cirrhosis risk in C282Y homozygotes. These findings remained significant in the subpopulation with available liver histology. The population-attributable fractions were 5.6% for PCSK7:rs236918, 13.8% for PNPLA3:rs738409, 6.5% for TM6SF2:rs58542926 and 24.0% for carriage of all three variants combined. CONCLUSIONS: The risk of cirrhosis associated with carriage of PCSK7:rs236918 was confirmed in this much larger population of C282Y homozygotes. In addition, PNPLA3:rs738409 and TM6SF2:rs58542926 were established as significant additional risk factors. More detailed genetic testing of C282Y homozygotes would allow risk stratification and help guide future management
Trophic niche overlap between native freshwater mussels (Order: Unionida) and the invasive Corbicula fluminea
Freshwater mussels (Order Unionida) are highly threatened. Interspecific competition for food sources with invasive alien species is considered to be one of the factors responsible for their decline because successful invaders are expected to have wider trophic niches and more flexible feeding strategies than their native counterparts. In this study, carbon (ÎŽ13C: 13C/12C) and nitrogen (ÎŽ15N: 15N/14N) stable isotopes were used to investigate the trophic niche overlap between the native freshwater mussel species, Anodonta anatina, Potomida littoralis, and Unio delphinus, and the invasive bivalve Corbicula fluminea living in sympatry in the Tua basin (south-west Europe). The species presenting the widest trophic niches were C. fluminea and A. anatina, which indicate that they have broader diets than U. delphinus and P. littoralis. Nonetheless, all the species assimilated microphytobenthos, sediment organic matter, and detritus derived from vascular plants, although with interspecific variability in the assimilated proportions of each source. The trophic niche of the invasive species overlapped with the trophic niche of all the native species, with the extent varying between sites and according to the species. From the three native species analysed, Potomida littoralis may be at a higher risk for competition for food with C. fluminea in the Tua basin, if food sources become limited, because this native mussel presented the narrowest trophic niche across sites and the highest probability of overlapping with the trophic niche of C. fluminea. Given the global widespread distribution of C. fluminea, the implementation of management measures devoted to the control or even eradication of this invasive alien species should be a conservation priority given its potential for competition with highly threatened native freshwater mussels.V.M. and P.C. were supported by doctoral grants SFRH/BD/108298/2015 and SFRH/BD/131814/2017, respectively, from
the Portuguese Foundation for Science and TechnologyâFCT through
POPH/FSE funds. FCT also supported M.L.L. under contract
(2020.03608.CEECIND). This study was conducted within the project
FRESHCO â Multiple implications of invasive species on Freshwater
Mussel coextinction processes, supported by FCT and COMPETE
funds (contract: PTDC/AGRFOR/1627/2014). This study was also
supported by national funds through FCT â Foundation for Science
and Technology within the scope of UIDB/04423/2020 and
UIDP/04423/2020. We thank Jacinto Cunha for providing Figure 1.info:eu-repo/semantics/publishedVersio
The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe
Saturn's largest moon, Titan, remains an enigma, explored only by remote sensing from Earth, and by the Voyager and Cassini spacecraft. The most puzzling aspects include the origin of the molecular nitrogen and methane in its atmosphere, and the mechanism(s) by which methane is maintained in the face of rapid destruction by photolysis. The Huygens probe, launched from the Cassini spacecraft, has made the first direct observations of the satellite's surface and lower atmosphere. Here we report direct atmospheric measurements from the Gas Chromatograph Mass Spectrometer (GCMS), including altitude profiles of the constituents, isotopic ratios and trace species ( including organic compounds). The primary constituents were confirmed to be nitrogen and methane. Noble gases other than argon were not detected. The argon includes primordial Ar-36, and the radiogenic isotope Ar-40, providing an important constraint on the outgassing history of Titan. Trace organic species, including cyanogen and ethane, were found in surface measurements.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62703/1/nature04122.pd
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