Vegetation Dynamics of Campos Under Grazing/Fire Regimes in Southern Brazil

Natural grassland vegetation in Southern Brazil, known as campos, has most likely evolved under a disturbance regime that included fire and grazing (Pillar et al., 1997). Nowadays, the composition of the vegetation of campos is grazing- and fire-dependent (Boldrini et al., 1997). Its importance can be evaluated by the fact that it represents 37 % of the state’s area and provides 77 % of the slaughtered cattle at Rio Grande do Sul (Barcellos et al., 2002). The objective of this experiment was to evaluate the vegetation dynamics of campos under grazing/fire regimes in order to explore the resilience of the vegetation under the regimes studied

Next-to-leading order QCD calculations with parton showers II: soft singularities

Programs that calculate observables in quantum chromodynamics at next-to-leading order typically generate events that consist of partons rather than hadrons -- and just a few partons at that. These programs would be much more useful if the few partons were turned into parton showers, which could be given to one of the Monte Carlo event generators to produce hadron showers. In a previous paper, we have seen how to generate parton showers related to the final state collinear singularities of the perturbative calculation for the example of e+ + e- --> 3 jets. This paper discusses the treatment of the soft singularities.Comment: 26 pages with 5 figures. This version is close to the version to be publishe

HERA Physics Beyond the Standard Model

The prospects of physics beyond the standard model in deep inelastic scattering are reviewed, emphasizing some scenarios which attained attention after the observation of an excess of events with large momentum transfer at HERA.Comment: 8 pages, LaTeX, uses iop style files and axodraw.sty, Talk presented at the 3rd UK Phenomenology Workshop on HERA Physics, September 1998, Durha

Coherent Parton Showers with Local Recoils

We outline a new formalism for dipole-type parton showers which maintain exact energy-momentum conservation at each step of the evolution. Particular emphasis is put on the coherence properties, the level at which recoil effects do enter and the role of transverse momentum generation from initial state radiation. The formulated algorithm is shown to correctly incorporate coherence for soft gluon radiation. Furthermore, it is well suited for easing matching to next-to-leading order calculations.Comment: 24 pages, 3 figure

Recria de novilhas de corte em pastagens naturais – metaanálise da produção animal

Irearing beef heifers in Rio Grande do Sul has been performed, mostly, in natural grasslands. This category has considerable nutrition requirements when mating at 24 monthswas proposed. This could need adjustment of grazing intensity to provide gains required for this category. The aim of this work was to characterize and to analyze possible relations not apparent, through of meta-analysis, with livestock data from nine experiments performed with heifers between seven and 26 months of age. Analyzed variables were carrying capacity(CC), average daily gain (ADG) and live weight gain per area (GPV). Data were transformed vectorially by standardizing by the range and submitted to multivariate analyzes of cluster and ordination using Euclidean distance as a measure of similarity. Cluster analyzes showed five groups of sampling units (p=0.02). ADG was the variable with highest correlation (R=0.98) with axis I, which explained most of data variation (64.27%). CC was the variable most correlated (R=0.98) with axis II, which explained 32.24% of results. The GPV was in the intermediate position it being 74.15% and 57.26% related to the axes I and II, respectively. From analyzed variables, ADG was the variable that explained most of data’s variability.A recria de novilhas de corte no Rio Grande do Sul (RS) tem sido realizada, majoritariamente, em pastagens naturais. Esta categoria possui consideráveis necessidades nutricionais quando se objetiva acasalar aos 24 meses, portanto, requerendo ajustes da intensidade de pastejo que proporcionem os ganhos requeridos. O objetivo deste trabalho  foi caracterizar e analisar possíveis relações não aparentes em estudos individuais, por meio de um estudo meta-analítico, em dados de produção animal oriundos de nove experimentos realizados de 2000 a 2012, com recria de fêmeas em pastagens naturais no RS. A base de dados foi composta por 208 observações, as quais avaliaram 679 novilhas de corte, entre sete e 26 meses de idade. As variáveis analisadas foram carga animal (CA), ganho médio diário (GMD) e ganho de peso vivo por área (GPV). Os dados foram transformados vetorialmente pela amplitude e submetidos às análises multivariadas de agrupamento e ordenação utilizando a distância Euclidiana como medida de semelhança (software MULTIV). A análise de agrupamento formou cinco grupos de unidades amostrais (p=0,02). O GMD foi a variável de maior correlação (r=0,98) com o eixo I, o qual explicou a maior variação dos resultados (64,27%). A CA foi a variável de maior correlação (R=0,98) com o eixo II, o qual explicou 32,24% dos resultados. O GPV (0,581 kg/ha/dia) esteve em uma posição intermediária estando 74,15% e 57,26% relacionado aos eixos I e II, respectivamente. Para as variáveis analisadas, GMD foi a variável que explicou a maior variabilidade dos resultados

Hadronic final states in deep-inelastic scattering with Sherpa

We extend the multi-purpose Monte-Carlo event generator Sherpa to include processes in deeply inelastic lepton-nucleon scattering. Hadronic final states in this kinematical setting are characterised by the presence of multiple kinematical scales, which were up to now accounted for only by specific resummations in individual kinematical regions. Using an extension of the recently introduced method for merging truncated parton showers with higher-order tree-level matrix elements, it is possible to obtain predictions which are reliable in all kinematical limits. Different hadronic final states, defined by jets or individual hadrons, in deep-inelastic scattering are analysed and the corresponding results are compared to HERA data. The various sources of theoretical uncertainties of the approach are discussed and quantified. The extension to deeply inelastic processes provides the opportunity to validate the merging of matrix elements and parton showers in multi-scale kinematics inaccessible in other collider environments. It also allows to use HERA data on hadronic final states in the tuning of hadronisation models.Comment: 32 pages, 22 figure

PYTHIA 6.4 Physics and Manual

The PYTHIA program can be used to generate high-energy-physics `events', i.e. sets of outgoing particles produced in the interactions between two incoming particles. The objective is to provide as accurate as possible a representation of event properties in a wide range of reactions, within and beyond the Standard Model, with emphasis on those where strong interactions play a role, directly or indirectly, and therefore multihadronic final states are produced. The physics is then not understood well enough to give an exact description; instead the program has to be based on a combination of analytical results and various QCD-based models. This physics input is summarized here, for areas such as hard subprocesses, initial- and final-state parton showers, underlying events and beam remnants, fragmentation and decays, and much more. Furthermore, extensive information is provided on all program elements: subroutines and functions, switches and parameters, and particle and process data. This should allow the user to tailor the generation task to the topics of interest.Comment: 576 pages, no figures, uses JHEP3.cls. The code and further information may be found on the PYTHIA web page: http://www.thep.lu.se/~torbjorn/Pythia.html Changes in version 2: Mistakenly deleted section heading for "Physics Processes" reinserted, affecting section numbering. Minor updates to take into account referee comments and new colour reconnection option