1,043 research outputs found
Farmers on film in the fight against striga
With the widespread scaling back of agricultural extension services in Africa, those with a responsibility to deliver information to rural communities are learning to follow new channels. In West Africa, the International Crops Research Institute for the Semi Arid Tropics (ICRISAT) has built on experiences gained by the Africa Rice Center (AfricaRice) in developing a series of ten farmer-to-farmer videos. The ten films are now being widely shown to support rural learning on practical and affordable ways to control one of Africa's most serious weeds - striga..
O(\alpha^2 \ln(m_\mu/m_e)) Corrections to Electron Energy Spectrum in Muon Decay
O(\alpha^2 \ln(m_\mu/m_e)) corrections to electron energy spectrum in muon
decay are computed using perturbative fragmentation function approach. The
magnitude of these corrections is comparable to anticipated precision of the
TWIST experiment at TRIUMF where Michel parameters will be extracted from the
measurement of the electron energy spectrum in muon decay.Comment: 8 pages, LaTeX, revtex4.cls, 1 PostScript figur
La bóveda tabicada en el siglo XXI
New interactive equilibrium methods for the design and analysis of masonry structures have facilitated the construction of masonry structures with a formal language well beyond what is typically associated with compression-only architecture. These developments have also rekindled interest in tile vaulting, and led to a rediscovery of this traditional building technique.
To ensure that tile vaults with new, complex shapes can still be built economically, the construction processes involved in the realisation of these structures have adapted. For example, cheaper and simpler falsework systems have been introduced. In addition, a wide variety of materials have been experimented with to be able to build more sustainable vaulted structures with local resources.
This paper presents a review of the latest innovations in tile vaulting, based on the most representative works of the past few years with respect to shape, construction method and the use of materials.Los nuevos métodos interactivos de equilibrio para diseñar y analizar estructuras de fábrica han facilitado la construcción de este tipo de estructuras con un lenguaje formal normalmente no asociado a las estructuras a compresión. Estos avances también han reavivado el interés por la bóveda tabicada, y han dado lugar a un redescubrimiento de esta técnica constructiva tradicional.
Los procesos constructivos han sido adaptados para garantizar que las nuevas bóvedas tabicadas de formas complejas puedan continuar materializándose de una manera económica. Por ejemplo, se han introducido sistemas de cimbrado más baratos y sencillos. Asà mismo, se ha experimentado con una gran variedad de materiales que permitan construir estructuras abovedadas más sostenibles con recursos locales.
Este artÃculo presenta una revisión de las últimas innovaciones en técnica tabicada basándose en las obras más representativas de los últimos años con respecto a la forma, el método constructivo y el uso de materiales
The Ontology of Intentional Agency in Light of Neurobiological Determinism: Philosophy Meets Folk Psychology
The moot point of the Western philosophical rhetoric about free will
consists in examining whether the claim of authorship to intentional, deliberative
actions fits into or is undermined by a one-way causal framework of determinism.
Philosophers who think that reconciliation between the two is possible are known as
metaphysical compatibilists. However, there are philosophers populating the other
end of the spectrum, known as the metaphysical libertarians, who maintain that claim
to intentional agency cannot be sustained unless it is assumed that indeterministic
causal processes pervade the action-implementation apparatus employed by the agent.
The metaphysical libertarians differ among themselves on the question of whether the
indeterministic causal relation exists between the series of intentional states and
processes, both conscious and unconscious, and the action, making claim for what has
come to be known as the event-causal view, or between the agent and the action,
arguing that a sort of agent causation is at work. In this paper, I have tried to propose
that certain features of both event-causal and agent-causal libertarian views need to be
combined in order to provide a more defendable compatibilist account accommodating
deliberative actions with deterministic causation. The ‘‘agent-executed-eventcausal
libertarianism’’, the account of agency I have tried to develop here, integrates
certain plausible features of the two competing accounts of libertarianism turning
them into a consistent whole. I hope to show in the process that the integration of these
two variants of libertarianism does not challenge what some accounts of metaphysical
compatibilism propose—that there exists a broader deterministic relation between the
web of mental and extra-mental components constituting the agent’s dispositional
system—the agent’s beliefs, desires, short-term and long-term goals based on them,
the acquired social, cultural and religious beliefs, the general and immediate and
situational environment in which the agent is placed, etc. on the one hand and the
decisions she makes over her lifetime on the basis of these factors. While in the
‘‘Introduction’’ the philosophically assumed anomaly between deterministic causation
and the intentional act of deciding has been briefly surveyed, the second section is
devoted to the task of bridging the gap between compatibilism and libertarianism. The
next section of the paper turns to an analysis of folk-psychological concepts and
intuitions about the effects of neurochemical processes and prior mental events on the
freedom of making choices. How philosophical insights can be beneficially informed
by taking into consideration folk-psychological intuitions has also been discussed,
thus setting up the background for such analysis. It has been suggested in the end that
support for the proposed theory of intentional agency can be found in the folk-psychological intuitions, when they are taken in the right perspective
Bounds on the mass of the b' quark, revisited
Recent results from the DELPHI collaboration led us to review the present
bounds on the b' quark mass. We use all available experimental data for m_b' >
96 GeV to constrain the b' quark mass as a function of the
Cabibbo-Kobayashi-Maskawa elements in a sequential four generations model. We
find that there is still room for a b' with a mass larger than 96 GeV.Comment: 9 pages and 7 figures. REVTEX
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Phosphonium-based polythiophene conjugated polyelectrolytes with different surfactant counterions: thermal properties, self-assembly and photovoltaic performances
© 2020 Society of Industrial Chemistry Phosphonium-based polythiophene conjugated polyelectrolytes (CPEs) with three different counterions (dodecylsulfate, octylsulfate and perfluorooctane sulfonate) are synthesized to determine how the nature of the counterion affects the thermal properties, the self-assembly in thin films and the performance as the cathode interfacial layer in polymer solar cells (PSCs). The counterion has a significant effect on the thermal properties of the CPEs, affecting both their glass transition and crystalline behaviour. Grazing-incidence wide-angle X-ray scattering studies also indicate that changing the nature of the counterion influences the microstructural organization in thin films (face-on versus edge-on orientation). The affinity of the CPEs with the underlying photoactive layer in PSCs is highly correlated with the counterion species. Finally, in addition to an increase of the power conversion efficiency of ca 15% when using these CPEs as cathode interfacial layers in PSCs, a higher device stability is noted, compared to a reference device with a calcium interlayer. © 2020 Society of Industrial Chemistry
Vector boson pair production at the LHC
We present phenomenological results for vector boson pair production at the
LHC, obtained using the parton-level next-to-leading order program MCFM. We
include the implementation of a new process in the code, pp -> \gamma\gamma,
and important updates to existing processes. We incorporate fragmentation
contributions in order to allow for the experimental isolation of photons in
\gamma\gamma, W\gamma, and Z\gamma production and also account for gluon-gluon
initial state contributions for all relevant processes. We present results for
a variety of phenomenological scenarios, at the current operating energy of
\sqrt{s} = 7 TeV and for the ultimate machine goal, \sqrt{s} = 14 TeV. We
investigate the impact of our predictions on several important distributions
that enter into searches for new physics at the LHC.Comment: 35 pages, 14 figure
Window on Higgs Boson: Fourth Generation Decays Revisited
Direct and indirect searches of the Higgs boson suggest that 113 GeV
170 GeV is likely. With the LEP era over and the
Tevatron Run II search via arduous, we revisit a case where
or jets could arise via strong pair
production. In contrast to 10 years ago, the tight electroweak constraint on
-- (hence --) splitting reduces FCNC
, rates, making naturally competitive.
Such a "cocktail solution" is precisely the mix that could evade the CDF search
for , and the may well be lurking below the top. In
light of the Higgs program, this two-in-one strategy should be pursued.Comment: 4 pages, RevTex, 4 eps figures, One more figure, version to be
published in Phys. Rev.
Next-to-Leading Order Cross Sections for Tagged Reactions
We extend the phase space slicing method of Giele, Glover and Kosower for
performing next-to-leading order jet cross section calculations in two
important ways: we show how to include fragmentation functions and how to
include massive particles. These extensions allow the application of this
method to not just jet cross sections but also to cross sections in which a
particular final state particle, including a or -meson, is tagged.Comment: 36 pages, Latex Small corrections to text. To appear in Phys. Rev.
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