Tree Species Effects on Soil Properties in Experimental Plantations in Tropical Moist Forest

We resampled one of the earliest replicated experimental sites used to investigate the impacts of native tropical tree species on soil properties, to examine longer term effects to 1-m depth. The monodominant stands, established in abandoned pasture in 1988 at La Selva Biological Station, Costa Rica, contained six species, including one exotic, Pinus patula ssp. tecunumanii (Eguiluz & J.P. Perry) Styles, and five native species: Pentaclethra macroloba (Willd.) Ktze (N2-fixing); Hyeronima alchorneoides Allemao; Virola koschnyi Warb.; Vochysia ferruginea Mart.; and Vochysia guatemalensis J.D. Smith. Soil organic carbon (SOC) differed significantly among species in the surface (0–15-cm) layer, ranging from 44.5 to 55.1 g kg1, compared with 46.6 and 50.3 g kg1 in abandoned pasture and mature forest, respectively. The change in surface SOC over 15 yr ranged from 0.03 to 0.66 Mg C ha1 yr1. The species differed in the quantity and chemical composition of their detrital production. Soil organic C was significantly correlated with fine-root growth, but not with aboveground detrital inputs. Soil organic C increased with potential C mineralization on a grams of C basis, indicating that species influenced both the quality and quantity of SOC. Contrary to expectations, SOC declined with increasing fine-root lignin concentrations, indicating that ligninderived C did not dominate refractory SOC pools. We hypothesize that differences among species in the capacity to increase SOC stocks involved fine-root traits that promoted soil microbial turnover and, thus, greater production of recalcitrant, microbial-derived C fractions

Beam Measurement Systems for the CERN Antiproton Decelerator (AD)

The new, low-energy antiproton physics facility at CERN has been successfully commissioned and has been delivering decelerated antiprotons at 100 MeV/c since July 2000. The AD consists of one ring where the 3.5 GeV/c antiprotons produced from a production target are injected, rf manipulated, stochastically cooled, decelerated (with further stages involving additional stochastic and electron cooling and rf manipulation) and extracted at 100 MeV/c. While proton test beams of sufficient intensity could be used for certain procedures in AD commissioning, this was not possible for setting-up and routine operation. Hence, special diagnostics systems had to be developed to obtain the beam and accelerator characteristics using the weak antiproton beams of a few 10E7 particles at all momenta from 3.5 GeV/c down to 100 MeV/c. These include systems for position measurement, intensity, beam size measurements using transverse aperture limiters and scintillators and Schottky-based tools. This paper gives an overall view of these systems and their usage

Design and Performance of a Pilot Scale High-Gradient Magnetic Filter Using a Mandhala Magnet and Its Application for Soy-Whey Protein Purification

The scalability of economic high-gradient magnetic separation (HGMS) technology is essential in order to demonstrate the feasibility of the concept. One of the means is the application of a permanent magnet with a hollow cylindrical volume made from identical magnetic blocks (e.g., Mandhala), another is the development of a High-Gradient Magnetic Filter (HGMF) with a new backwashing concept. The Mandhala (Magnetic Arrangement for Novel Discrete Halbach Layout) magnet produces a dipolar transversal magnetic field in the center of the bore and its usable volume is easily adaptable to the separation device\u27s extensions. The chapter presents the pilot scale design of the Mandhala magnet and the HGMF as well as experimental performance tests using a water-magnetic beads model system. Subsequently, experiments using soy-whey as a real feedstock demonstrate the purification of the protein Bowman-Birk inhibitor (BBI), an agent against cancer and multiples sclerosis

Conversion of the PS complex as LHC proton pre-injector

CERNs Large Hadron Collider (LHC) [1][2] will be supplied with protons from the injector chain Linac2-PS Booster (PSB)-PS-SPS (Fig. 1). The required transverse beam brilliance (intensity/emittance) is almost twice that of current PS beams and the LHC bunch spacing of 25 ns must be impressed on the beam before its transfer to the SPS. The scheme involves new RF harmonics in the PSB and the PS, an increase of the PSB energy, and two-batch filling of the PS. After a successful test of the main ingredients, a project for converting the PS complex was launched in 1994. Major additions are (i) h=1 RF systems in the PSB, (ii) upgrading of the PSB main magnet supply from 1 to 1.4 GeV operation, (iii) new magnets, septa, power supplies, kicker pulsers for the PSB-PS beam transfer, (iv) 40 and 80 MHz systems in the PS, (v) beam profile measurement devices with improved resolution. A significant part of the effort is being provided by TRIUMF under the Canada-CERN co-operation agreement on the LHC

The effects of CO2, climate and land-use on terrestrial carbon balance, 1920-1992: An analysis with four process-based ecosystem models

The concurrent effects of increasing atmospheric CO2 concentration, climate variability, and cropland establishment and abandonment on terrestrial carbon storage between 1920 and 1992 were assessed using a standard simulation protocol with four process-based terrestrial biosphere models. Over the long-term(1920–1992), the simulations yielded a time history of terrestrial uptake that is consistent (within the uncertainty) with a long-term analysis based on ice core and atmospheric CO2 data. Up to 1958, three of four analyses indicated a net release of carbon from terrestrial ecosystems to the atmosphere caused by cropland establishment. After 1958, all analyses indicate a net uptake of carbon by terrestrial ecosystems, primarily because of the physiological effects of rapidly rising atmospheric CO2. During the 1980s the simulations indicate that terrestrial ecosystems stored between 0.3 and 1.5 Pg C yr−1, which is within the uncertainty of analysis based on CO2 and O2 budgets. Three of the four models indicated (in accordance with O2 evidence) that the tropics were approximately neutral while a net sink existed in ecosystems north of the tropics. Although all of the models agree that the long-term effect of climate on carbon storage has been small relative to the effects of increasing atmospheric CO2 and land use, the models disagree as to whether climate variability and change in the twentieth century has promoted carbon storage or release. Simulated interannual variability from 1958 generally reproduced the El Niño/Southern Oscillation (ENSO)-scale variability in the atmospheric CO2 increase, but there were substantial differences in the magnitude of interannual variability simulated by the models. The analysis of the ability of the models to simulate the changing amplitude of the seasonal cycle of atmospheric CO2 suggested that the observed trend may be a consequence of CO2 effects, climate variability, land use changes, or a combination of these effects. The next steps for improving the process-based simulation of historical terrestrial carbon include (1) the transfer of insight gained from stand-level process studies to improve the sensitivity of simulated carbon storage responses to changes in CO2 and climate, (2) improvements in the data sets used to drive the models so that they incorporate the timing, extent, and types of major disturbances, (3) the enhancement of the models so that they consider major crop types and management schemes, (4) development of data sets that identify the spatial extent of major crop types and management schemes through time, and (5) the consideration of the effects of anthropogenic nitrogen deposition. The evaluation of the performance of the models in the context of a more complete consideration of the factors influencing historical terrestrial carbon dynamics is important for reducing uncertainties in representing the role of terrestrial ecosystems in future projections of the Earth system

ELENA, a preliminary cost and feasibility study

To produce dense pbar beams at very low energies (100-200 keV), a small decelerator ring could be built and installed between the existing AD ring and the experimental area. Phase-space blowup during deceleration would be compensated by electron cooling in order to obtain final emittances comparable to the 5MeV beam presently delivered by the AD. This report describes preliminary machine parameters and layout of ELENA and also gives an approximate estimate of cost and manpower needs