Transfer of radionuclides from soil to vegetation in selected Irish ecosystems

This thesis details the findings of a study relating the transfer of 238U, 228Ra (232Th), 226Ra, and 137Cs from soil to vegetation in an Atlantic blanket bog, upland blanket bog and semi-natural grassland situated along the north-west coast of Ireland. The results of this study provide information on the uptake of these radionuclides by the indigenous vegetation found present in these ecosystems. The ecosystems chosen are internationally recognizable ecosystems and provide a wide variety of vegetation species and contrasting soil physiochemical properties which allow the influence of these parameters on radionuclide uptake to be assessed. The levels of radionuclides in the soil and vegetation were measured using gamma spectrometry, alpha spectrometry and ICP-MS. The nutrient status of the vegetation and soil physiochemical properties were measured using atomic absorption, flame photometry and other analytical techniques. The results of the study indicate that the uptake of 238U and 228Ra (232Th) by vegetation from all three ecosystems was negligible as the levels in all vegetation was below the limits of detection for the methods used in this study. These results appear to indicate that the vegetation studied do not possess the ability to accumulate significant levels of these radionuclides however this assumption cannot be upheld in the case of the Atlantic blanket bog as the levels in the soil of this ecosystem were too low for detection. Similar results were obtained for 226Ra uptake in both the Atlantic blanket bog and grassland for all vegetation with the exception of H. lanatus from the grassland ecosystem. Radium-226 uptake in upland blanket bog was higher and was detectable in the majority of vegetation indigenous to this ecosystem. Transfer factor values ranged from 0.07 to 2.35 and the TF values for E. tetralix were significantly higher than all other vegetation studied. This species of heather demonstrated the ability to accumulate 226Ra to a greater extent than all other vegetation. The uptake of 226Ra by upland blanket bog vegetation appears to be significantly influenced by a range of soil physiochemical properties. The nutrient status of the vegetation, in particular the calcium content in the vegetation appears to have a negative impact on the uptake of this radionuclide. Potassium-40 was detectable in all vegetation present in the three ecosystems and the levels in the grassland soil were significantly higher than the levels in both bogland soils. Transfer factor values for Atlantic blanket bog vegetation ranged from 0.9 to 13 .8 and were significantly higher in E. vaginatum in comparison to C. vulgaris. Potassium-40 TF values for upland blanket bog vegetation on average ranged from 1.4 for C. vulgaris (stems) to 5.2 for E. vaginatum and were statistically similar for all species of vegetation. Transfer factor values for grassland vegetation ranged from 0.7 to 3.8 and were also statistically similar for all species of vegetation indicating that the transfer of 40K to vegetation within the upland bog and grassland ecosystem is not dependent on plant species. Comparisons of 40K TF values for all three ecosystems indicate that the uptake in E. vaginatum from the Atlantic blanket bog was statistically higher than all other vegetation studied. This appears to indicate that E. vaginatum has the ability to accumulate 40K, however, this species of vegetation was also present in the upland blanket and did not demonstrate the same behaviour. The uptake of 40K by vegetation from all three ecosystems was significantly affected by a range of soil physiochemical properties and in some cases the results were contradictory in nature possibly indicating that the affect of these parameters on 40K uptake is species dependent. The most obvious trend in the data was the influence of soil CEC and magnesium levels in vegetation on 40K TF values. A positive correlation was apparent between the CEC of the soil and 40K uptake in vegetation from both the Atlantic blanket bog and grassland ecosystem. A similar trend was apparent between magnesium levels in vegetation and 40K TF values for the upland blanket bog and grassland vegetation. Caesium-13 7 levels were found to be significantly higher in the two bogland soils in comparison to the grassland soil and levels of 137Cs decreased with increasing soil depth. Transfer factor values for Atlantic blanket bog vegetation ranged from 1.9 to 9.6 and TF values were significantly higher in the leaves o f C. vulgaris in comparison to all other vegetation from this ecosystem. Caesium-13 7 TF values for the upland blanket bog vegetation on average ranged from 0.29 for E. tetralix to 1.6 for C. vulgaris. Uptake by the leaves of C. vulgaris was significantly higher than all other vegetation present thereby supporting the trend found within the Atlantic blanket bog vegetation. These results appear to indicate that the leaves of C. vulgaris have the ability to accumulate significant quantities of 137Cs and also that the uptake of 137Cs by this vegetation is dependent on plant compartment as the stems of this vegetation contained significantly lower levels than the leaves in both ecosystems. The uptake of 137Cs by grassland vegetation was very low and was only detectable in a fraction of the vegetation sampled. Caesium-137 TF values for grassland vegetation were in general lower than 0.02. The impact of soil physiochemical properties and nutrient status of vegetation on 137Cs uptake by vegetation appears to be complex and in some cases contradictory. The most apparent trend in the data was the positive influence of vegetation nutrients on 137Cs uptake in particular the magnesium levels present in the vegetation and to a lesser extent the calcium levels present. The results in general indicate that the uptake of 226Ra, 40K and 137Cs by the chosen vegetation is varied and complex and is significantly dependent on the species of vegetation, soil radionuclide concentration, soil physiochemical properties and the nutrient status of the vegetation.

Comparative genome analysis of Pseudomonas knackmussii B13, the first bacterium known to degrade chloroaromatic compounds.

Pseudomonas knackmussii B13 was the first strain to be isolated in 1974 that could degrade chlorinated aromatic hydrocarbons. This discovery was the prologue for subsequent characterization of numerous bacterial metabolic pathways, for genetic and biochemical studies, and which spurred ideas for pollutant bioremediation. In this study, we determined the complete genome sequence of B13 using next generation sequencing technologies and optical mapping. Genome annotation indicated that B13 has a variety of metabolic pathways for degrading monoaromatic hydrocarbons including chlorobenzoate, aminophenol, anthranilate and hydroxyquinol, but not polyaromatic compounds. Comparative genome analysis revealed that B13 is closest to Pseudomonas denitrificans and Pseudomonas aeruginosa. The B13 genome contains at least eight genomic islands [prophages and integrative conjugative elements (ICEs)], which were absent in closely related pseudomonads. We confirm that two ICEs are identical copies of the 103 kb self-transmissible element ICEclc that carries the genes for chlorocatechol metabolism. Comparison of ICEclc showed that it is composed of a variable and a 'core' region, which is very conserved among proteobacterial genomes, suggesting a widely distributed family of so far uncharacterized ICE. Resequencing of two spontaneous B13 mutants revealed a number of single nucleotide substitutions, as well as excision of a large 220 kb region and a prophage that drastically change the host metabolic capacity and survivability.

Comparative genome analysis of Pseudomonas knackmussii B13, the first bacterium known to degrade chloroaromatic compounds.

Pseudomonas knackmussii B13 was the first strain to be isolated in 1974 that could degrade chlorinated aromatic hydrocarbons. This discovery was the prologue for subsequent characterization of numerous bacterial metabolic pathways, for genetic and biochemical studies, and which spurred ideas for pollutant bioremediation. In this study, we determined the complete genome sequence of B13 using next generation sequencing technologies and optical mapping. Genome annotation indicated that B13 has a variety of metabolic pathways for degrading monoaromatic hydrocarbons including chlorobenzoate, aminophenol, anthranilate and hydroxyquinol, but not polyaromatic compounds. Comparative genome analysis revealed that B13 is closest to Pseudomonas denitrificans and Pseudomonas aeruginosa. The B13 genome contains at least eight genomic islands [prophages and integrative conjugative elements (ICEs)], which were absent in closely related pseudomonads. We confirm that two ICEs are identical copies of the 103 kb self-transmissible element ICEclc that carries the genes for chlorocatechol metabolism. Comparison of ICEclc showed that it is composed of a variable and a 'core' region, which is very conserved among proteobacterial genomes, suggesting a widely distributed family of so far uncharacterized ICE. Resequencing of two spontaneous B13 mutants revealed a number of single nucleotide substitutions, as well as excision of a large 220 kb region and a prophage that drastically change the host metabolic capacity and survivability.

CMS physics technical design report, volume II: Physics performance

CMS is a general purpose experiment, designed to study the physics of pp collisions at 14 TeV at the Large Hadron Collider ( LHC). It currently involves more than 2000 physicists from more than 150 institutes and 37 countries. The LHC will provide extraordinary opportunities for particle physics based on its unprecedented collision energy and luminosity when it begins operation in 2007. The principal aim of this report is to present the strategy of CMS to explore the rich physics programme offered by the LHC. This volume demonstrates the physics capability of the CMS experiment. The prime goals of CMS are to explore physics at the TeV scale and to study the mechanism of electroweak symmetry breaking - through the discovery of the Higgs particle or otherwise. To carry out this task, CMS must be prepared to search for new particles, such as the Higgs boson or supersymmetric partners of the Standard Model particles, from the start- up of the LHC since new physics at the TeV scale may manifest itself with modest data samples of the order of a few fb(-1) or less. The analysis tools that have been developed are applied to study in great detail and with all the methodology of performing an analysis on CMS data specific benchmark processes upon which to gauge the performance of CMS. These processes cover several Higgs boson decay channels, the production and decay of new particles such as Z' and supersymmetric particles, B-s production and processes in heavy ion collisions. The simulation of these benchmark processes includes subtle effects such as possible detector miscalibration and misalignment. Besides these benchmark processes, the physics reach of CMS is studied for a large number of signatures arising in the Standard Model and also in theories beyond the Standard Model for integrated luminosities ranging from 1 fb(-1) to 30 fb(-1). The Standard Model processes include QCD, B-physics, diffraction, detailed studies of the top quark properties, and electroweak physics topics such as the W and Z(0) boson properties. The production and decay of the Higgs particle is studied for many observable decays, and the precision with which the Higgs boson properties can be derived is determined. About ten different supersymmetry benchmark points are analysed using full simulation. The CMS discovery reach is evaluated in the SUSY parameter space covering a large variety of decay signatures. Furthermore, the discovery reach for a plethora of alternative models for new physics is explored, notably extra dimensions, new vector boson high mass states, little Higgs models, technicolour and others. Methods to discriminate between models have been investigated. This report is organized as follows. Chapter 1, the Introduction, describes the context of this document. Chapters 2-6 describe examples of full analyses, with photons, electrons, muons, jets, missing E-T, B-mesons and tau's, and for quarkonia in heavy ion collisions. Chapters 7-15 describe the physics reach for Standard Model processes, Higgs discovery and searches for new physics beyond the Standard Model.

Inclusive J/psi production in pp collisions at root s=2.76 TeV

The ALICE Collaboration has measured inclusive J/psi production in pp collisions at a center-of-mass energy root s = 2.76 TeV at the LHC. The results presented in this Letter refer to the rapidity ranges vertical bar y vertical bar < 0.9 and 2.5 < y <4 and have been obtained by measuring the electron and muon pair decay channels, respectively. The integrated luminosities for the two channels are L-int(e) = 1.1 nb(-1) and L-int(mu) = 19.9 nb(-1), and the corresponding signal statistics are N-J/psi(e+e-) = 59 +/- 14 and N-J/psi(mu+mu-) = 1364 +/- 53. We present d sigma(J/psi)/dy for the two rapidity regions under study and, for the forward-y range, d(2)sigma(J/psi)/dydp(t) in the transverse momentum domain 0 < p(t) < 8 GeV/c. The results are compared with previously published results at root s = 7 TeV and with theoretical calculations. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved.

J/psi Polarization in pp Collisions at root s=7 TeV

The ALICE Collaboration has studied J/psi production in pp collisions at root s = 7 TeV at the LHC through its muon pair decay. The polar and azimuthal angle distributions of the decay muons were measured, and results on the J/psi polarization parameters lambda(theta) and lambda(phi) were obtained. The study was performed in the kinematic region 2: 5 < y < 4, 2 < p(t) < 8 GeV/c, in the helicity and Collins-Soper reference frames. In both frames, the polarization parameters are compatible with zero, within uncertainties.

Measurement of electrons from semileptonic heavy-flavor hadron decays in pp collisions at root s=7 TeV

The differential production cross section of electrons from semileptonic heavy-flavor hadron decays has been measured at midrapidity (\y\ < 0.5) in proton-proton collisions at root s = 7 TeV with ALICE at the LHC. Electrons were measured in the transverse momentum range 0.5 < p(t) < 8 GeV/c. Predictions from a fixed-order perturbative QCD calculation with next-to-leading-log resummation agree with the data within the theoretical and experimental uncertainties. DOI: 10.1103/PhysRevD.86.112007

(KsKs0)-K-0 correlations in pp collisions at root s=7 TeV from the LHC ALICE experiment

Identical neutral kaon pair correlations are measured in root s = 7 TeV pp collisions in the ALICE experiment. One-dimensional (KsKs0)-K-0 correlation functions in terms of the invariant momentum difference of kaon pairs are formed in two multiplicity and two transverse momentum ranges. The femtoscopic parameters for the radius and correlation strength of the kaon source are extracted. The fit includes quantum statistics and final-state interactions of the a(0)/f(0) resonance. (KsKs0)-K-0 correlations show an increase in radius for increasing multiplicity and a slight decrease in radius for increasing transverse mass, mT, as seen in pi pi correlations in pp collisions and in heavy-ion collisions. Transverse mass scaling is observed between the (KsKs0)-K-0 and pi pi radii. Also, the first observation is made of the decay of the f(2)'(1525) meson into the (KsKs0)-K-0 channel in pp collisions. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved.

Production of Muons from Heavy Flavor Decays at Forward Rapidity in pp and Pb-Pb Collisions at root s(NN)=2.76 TeV

The ALICE Collaboration has measured the inclusive production of muons from heavy-flavor decays at forward rapidity, 2.5 < y < 4, in pp and Pb-Pb collisions at root s(NN) = 2.76 TeV. The p(t)-differential inclusive cross section of muons from heavy-flavor decays in pp collisions is compared to perturbative QCD calculations. The nuclear modification factor is studied as a function of p(t) and collision centrality. A weak suppression is measured in peripheral collisions. In the most central collisions, a suppression of a factor of about 3-4 is observed in 6 < p(t) < 10 GeV/c. The suppression shows no significant p(t) dependence.

Production of K*(892)(0) and phi(1020) in pp collisions at root s=7 TeV

The production of K*(892)(0) and phi(1020) in pp collisions at root s = 7 TeV was measured by the ALICE experiment at the LHC. The yields and the transverse momentum spectra d(2)N/dydp(T) at midrapidity vertical bar y vertical bar < 0.5 in the range 0 < p(T) < 6 GeV/c for K*(892)(0) and 0.4 < p(T) < 6 GeV/c for phi(1020) are reported and compared to model predictions. Using the yield of pions, kaons, and Omega baryons measured previously by ALICE at root s = 7 TeV, the ratios K*/K-, phi/K*, phi/ K-, phi/pi(-), and (Omega + <(Omega)over bar>)/phi are presented. The values of the K*/K-, phi/K* and phi/K- ratios are similar to those found at lower centre-of-mass energies. In contrast, the phi/pi(-) ratio, which has been observed to increase with energy, seems to saturate above 200 GeV. The (Omega + (Omega) over bar)/phi ratio in the p(T) range 1-5 GeV/ c is found to be in good agreement with the prediction of the HIJING/B (B) over bar v2.0model with a strong colour field.