Rock magnetism and its application to palaeosols: A pilot study in a loess-palaeosol sequence of the Chacopam-Dean region

Rock maenetism techniques were applied to the study of the palaeosols and loess in the Chaco-Pampean plain region, Buenos Aires, Argentina; in addition, several types of non magnetic analysis were carried out: chemical analysis of ferrous and ferric, titanium and magnesium ions and x-Ray difraction. The magnetic susceptibilities of the Argentine palaeosol and loess exhibit different trends to those observed in the well known Chinese examples with which they are compared. In the Chacopampean succession the susceptibility of the loess is higher than that of the palaeosol. This can be explained by differences in the parental material imparting different magnetic properties. © 1998 Asociaciön Geolögica Argentina.Fil:Vasquez, C.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Walther, A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Orgeira, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Construcción de un magnetómetro elemental

Palabras clave: campo magnético terrestre; magnetómetro elemental.Construction of an elemental magnetometerKeywords: Earth Magnetic Field; cheap magnetometer

Investigating a process model for leader affective presence, interpersonal emotion regulation, and interpersonal behaviour in teams

Leader affective presence is the tendency of leaders to elicit feelings that are consistent among other individuals, and has been supported as a relevant personality trait for understanding teamwork. Drawing on a model that integrates personality and emotion regulation, this study aimed to expand research on affective presence by proposing team members’ perceptions of leader interpersonal emotion regulation as a process that explains how leader affective presence is related to team member behaviour. In the model, teamness—the perception that interdependence and reflexivity are required in the team—is presented as a boundary condition to the effects of affective presence via emotion regulation. Results of a study conducted with 99 teams showed that team member ratings of leader positive affective presence were linked to their perceptions that leaders had used affect-improving emotion regulation which in turn was associated with greater team citizenship behaviour. Contrariwise, team member ratings of leader negative affective presence were associated with perceived use of affect-worsening emotion regulation by leaders which in turn was associated with lower levels of team citizenship, but only when teams were low in teamness. These findings contribute to understanding how leaders’ individual differences are related to teamwork through affective processes

Does job crafting affect employee outcomes via job characteristics? A meta‐analytic test of a key job crafting mechanism

Job crafting refers to the self-initiated work behaviours employees use to change their job characteristics. According to job design theory, these crafting-induced changes in job characteristics should impact employee outcomes. Job characteristics can therefore be proposed as a key mechanism through which job crafting affects employee outcomes and we present cross-sectional meta-analytic structural equation modelling of this key mechanism (K = 58 independent samples, N = 20,347 employees). Results show significant indirect effects between task resource crafting and employee outcomes (well-being and positive job attitudes) via task resources, and significant indirect effects between social job crafting and employee outcomes (well-being and positive job attitudes) via social resources. Results also indicated that challenge and hindrance demand crafting increase job strain via increases in job demand. Overall, our findings indicate that job characteristics are an important job crafting mechanism, that employees may have difficulty in crafting job demands in ways that produce beneficial outcomes, and that future research needs to consider simultaneously the range of mechanisms through which job crafting affects outcomes

An international network to monitor the structure, composition and dynamics of Amazonian forests (RAINFOR)

The Amazon basin is likely to be increasingly affected by environmental changes: higher temperatures, changes in precipitation, CO2 fertilization and habitat fragmentation. To examine the important ecological and biogeochemical consequences of these changes, we are developing an international network, RAINFOR, which aims to monitor forest biomass and dynamics across Amazonia in a co-ordinated fashion in order to understand their relationship to soil and climate. The network will focus on sample plots established by independent researchers, some providing data extending back several decades. We will also conduct rapid transect studies of poorly monitored regions. Field expeditions analysed local soil and plant properties in the first phase (2001–2002). Initial results suggest that the network has the potential to reveal much information on the continental-scale relations between forest and environment. The network will also serve as a forum for discussion between researchers, with the aim of standardising sampling techniques and methodologies that will enable Amazonian forests to be monitored in a coherent manner in the coming decades

Discussing Quantum Aspects of Higher-Derivative 3D-Gravity in the First-Order Formalism

In this paper, we reassess the issue of deriving the propagators and identifying the spectrum of excitations associated to the vielbein and spin connection of (1+2)-D gravity in the presence of dynamical torsion, while working in the first-order formulation. A number of peculiarities is pointed out whenever the Chern-Simons term is taken into account along with a combination of bilinear terms in the torsion tensor. We present a procedure to derive the full set of propagators, based on an algebra of enlarged spin-type operators, and we discuss under which conditions the poles of the tree-level 2-point functions correspond to physical excitations that do not conflict with causality and unitarity

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

Regional and large-scale patterns in Amazon forest structure and function are mediated by variations in soil physical and chemical properties

Forest structure and dynamics have been noted to vary across the Amazon Basin in an east-west gradient in a pattern which coincides with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. To test this hypothesis and assess the importance of edaphic properties in affect forest structure and dynamics, soil and plant samples were collected in a total of 59 different forest plots across the Amazon Basin. Samples were analysed for exchangeable cations, C, N, pH with various Pfractions also determined. Physical properties were also examined and an index of soil physical quality developed. Overall, forest structure and dynamics were found to be strongly and quantitatively related to edaphic conditions. Tree turnover rates emerged to be mostly influenced by soil physical properties whereas forest growth rates were mainly related to a measure of available soil phosphorus, although also dependent on rainfall amount and distribution. On the other hand, large scale variations in forest biomass could not be explained by any of the edaphic properties measured, nor by variation in climate. A new hypothesis of self-maintaining forest dynamic feedback mechanisms initiated by edaphic conditions is proposed. It is further suggested that this is a major factor determining forest disturbance levels, species composition and forest productivity on a Basin wide scale