Making milpa, making life in La Mera Selva: a testimony of how Tzeltal peasants perform maize cultivation practices in the Lacandon Jungle, Mexico

This PhD thesis is a testimony of how Tzeltal peasants make milpa in the Lacandon Jungle, Chiapas, Mexico. It describes how they alternate maize cultivation practices with other activities in their lives through different juggling performances. These performances show how these indigenous peasants consider maize cultivation practices not only as agronomic activities but also as political, social and cultural actions. Therefore slash-and-mulch becomes a variant of land preparation and a response to a landownership conflict. Sowing becomes a negotiation with the environmental, technological and social circumstances of living in this tropical rainy forest. Weeding and bending are control practices and postponing/delegating them become peasant strategies to cope with the lack of basic services. Finally, harvesting is cutting the cobs from plants and strengthening the reasons and meanings to continue cultivating maize. These performances show how in the making of the milpa, Tzeltal peasants are making their lives. </p

KINETIC PROFILE AND INCIDENCE OF INJURIES AMONG HIGH PERFORMANCE TRAMPOLINE GYMNASTS

The purpose of this study was: a) Determine the differences among injured and noninjured trampolinists with regard to kinetic data collected; b) Determine if there were any associations between the type of injuries sustained and the kinetic data collected. A one year retrospective analysis of kinetic test results and medical records of a group of high performance trampolinists was performed. Fifteen participants between the ages of 10–20 participated in the study (9 males and 6 females). 40% of participants sustained an injury for which they sought medical advice. The incidence of injury per 1000hours of trampoline use was 2.3. Injured trampoline gymnasts had significantly lower range of motion of the left ankle and total work values for the left dorsiflexors. Coaches, gymnasts and parents should be educated about the potential risks and take measures in preventing injuries

Defining and identifying crop landraces

Awareness of the need for biodiversity conservation is now universally accepted, but most often recent conservation activities have focused on wild species. Crop species and the diversity between and within them has significant socioeconomic as well as heritage value. The bulk of genetic diversity in domesticated species is located in traditional varieties maintained by traditional farming systems. These traditional varieties, commonly referred to as landraces, are severely threatened by genetic extinction primarily due to their replacement by modern genetically uniform varieties. The conservation of landrace diversity has been hindered in part by the lack of an accepted definition to define the entity universally recognized as landraces. Without a definition it would be impossible to prepare an inventory and without an inventory changes in landrace constituency could not be recognized over time. Therefore, based on a literature review, workshop discussion and interviews with key informants, common characteristics of landraces were identified, such as: historical origin, high genetic diversity, local genetic adaptation, recognizable identity, lack of formal genetic improvement, and whether associated with traditional farming systems. However, although these characteristics are commonly present they are not always all present for any individual landrace; several crop-specific exceptions were noted relating to crop propagation method (sexual or asexual), breeding system (self-fertilized or cross-fertilized species), length of formal crop improvement, seed management (selection or random propagation) and use. This paper discusses the characteristics that generally constitute a landrace, reviews the exceptions to these characteristics and provides a working definition of a landrace. The working definition proposed is as follows: `a landrace is a dynamic population(s) of a cultivated plant that has historical origin, distinct identity and lacks formal crop improvement, as well as often being genetically diverse, locally adapted and associated with traditional farming systems

Diversities In Motion: Multifunctionality of Maize Production in Different Family Farming Systems in South and Central Mexico

Background: Maize agricultural policy in Mexico has focused on a monofunctional vision of maize as a basic commercial product, through a bimodal vision of production systems (commercial and subsistence). However, the evidence suggests that the challenge of thinking about the multifunctionality of this crop must be faced due to the complexity of its relationship within different strata of society, to more adequately reflect the diversity of systems based on maize, as well as their flexibility to respond to new challenges and opportunities, and to have better public policy designs. Objective: This work seeks to delve into the importance of the multifunctionality of maize within the context of different types of production units in Central and Southern Mexico, which represent families that make use of different production systems based on maize. This diversity is not a simple cultural curiosity, but rather reflects the complex use of maize cultivation as an economic and cultural mechanism that provides stability to Mexican families who depend on maize as their main crop. Methodology: To describe the multifunctionality of maize in Mexico, we adopted a qualitative approach through in-depth interviews with 51 maize producers from different types of production unit (PU) in the states of Oaxaca, Chiapas, Mexico, and Puebla. A study of production units (PU) typologies carried out with information from 16 states of the country was taken as a basis, where five types of PU were characterized according to their available resources, maize management, and their social characteristics. Results: It was found that: (1) there is a clearly distinguishable PU gradient (where, in addition to the existence of commercial and subsistence units, three others were identified, with direct implications for the design of public policy) that use maize with several purposes; (2) multifunctionality is associated with the diversity of uses and genetic materials that PUs have, and; (3) the variety of functions of maize changes according to the importance of maize in each type of unit and trough time. Implications: This work is positioned in favor of an expanded vision of the maize sector in Mexico instead of a dichotomous vision, where maize systems behave as a fluid continuum where the context of the PU’s affects their relationship with maize, and the way in which they use this crop to face social, climatic, and economic changes, as well as their preferences as consumers, traditions, and cultural identities. Conclusions: This complexity calls to thinking about a pluridiverse maize policy that understands the social complexity of this crop through the multifunctional support it offers to different types of UP’s based on maize systems, and how these differences require more sophisticated institutional approaches. Key words: multifunctionality of agriculture; maize; farm typologies; diversification of agricultural activities; diversity of maize-based systems

Measurement of Bottom versus Charm as a Function of Transverse Momentum with Electron-Hadron Correlations in p+p Collisions at sqrt(s)=200 GeV

The momentum distribution of electrons from semi-leptonic decays of charm and bottom for mid-rapidity |y|<0.35 in p+p collisions at sqrt(s)=200 GeV is measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) over the transverse momentum range 2 < p_T < 7 GeV/c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D/D^bar --> e^{+/-} K^{-/+} X (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV/c in p_T. A fixed-order-plus-next-to-leading-log (FONLL) perturbative quantum chromodynamics (pQCD) calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is \sigma_{b\b^bar}= 3.2 ^{+1.2}_{-1.1}(stat) ^{+1.4}_{-1.3}(syst) micro b.Comment: 432 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Measurement of the cross section of high transverse momentum Z→bb̄ production in proton–proton collisions at √s = 8 TeV with the ATLAS detector

This Letter reports the observation of a high transverse momentum Z→bb̄ signal in proton–proton collisions at √s=8 TeV and the measurement of its production cross section. The data analysed were collected in 2012 with the ATLAS detector at the LHC and correspond to an integrated luminosity of 19.5 fb−¹. The Z→bb̄ decay is reconstructed from a pair of b -tagged jets, clustered with the anti-ktkt jet algorithm with R=0.4R=0.4, that have low angular separation and form a dijet with pT>200 GeVpT>200 GeV. The signal yield is extracted from a fit to the dijet invariant mass distribution, with the dominant, multi-jet background mass shape estimated by employing a fully data-driven technique that reduces the dependence of the analysis on simulation. The fiducial cross section is determined to be σZ→bb¯fid=2.02±0.20 (stat.) ±0.25 (syst.)±0.06 (lumi.) pb=2.02±0.33 pb, in good agreement with next-to-leading-order theoretical predictions

Operation and performance of the ATLAS semiconductor tracker

The semiconductor tracker is a silicon microstrip detector forming part of the inner tracking system of the ATLAS experiment at the LHC. The operation and performance of the semiconductor tracker during the first years of LHC running are described. More than 99% of the detector modules were operational during this period, with an average intrinsic hit efficiency of (99.74±0.04)%. The evolution of the noise occupancy is discussed, and measurements of the Lorentz angle, δ-ray production and energy loss presented. The alignment of the detector is found to be stable at the few-micron level over long periods of time. Radiation damage measurements, which include the evolution of detector leakage currents, are found to be consistent with predictions and are used in the verification of radiation background simulations

Measurement of the correlation between flow harmonics of different order in lead-lead collisions at √sNN = 2.76 TeV with the ATLAS detector

Correlations between the elliptic or triangular flow coefficients vm (m=2 or 3) and other flow harmonics vn (n=2 to 5) are measured using √sNN=2.76 TeV Pb+Pb collision data collected in 2010 by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 7 μb−1. The vm−vn correlations are measured in midrapidity as a function of centrality, and, for events within the same centrality interval, as a function of event ellipticity or triangularity defined in a forward rapidity region. For events within the same centrality interval, v3 is found to be anticorrelated with v2 and this anticorrelation is consistent with similar anticorrelations between the corresponding eccentricities, ε2 and ε3. However, it is observed that v4 increases strongly with v2, and v5 increases strongly with both v2 and v3. The trend and strength of the vm−vn correlations for n=4 and 5 are found to disagree with εm−εn correlations predicted by initial-geometry models. Instead, these correlations are found to be consistent with the combined effects of a linear contribution to vn and a nonlinear term that is a function of v22 or of v2v3, as predicted by hydrodynamic models. A simple two-component fit is used to separate these two contributions. The extracted linear and nonlinear contributions to v4 and v5 are found to be consistent with previously measured event-plane correlations