845 research outputs found
The pion-kaon scattering amplitude constrained with forward dispersion relations up to 1.6 GeV
In this work we provide simple and precise parameterizations of the existing
scattering data from threshold up to 1.6 GeV, which are constrained to
satisfy forward dispersion relations as well as three additional threshold sum
rules. We also provide phenomenological values of the threshold parameters and
of the resonance poles that appear in elastic scattering.Comment: References and comments added. Some errata corrected. Results
unchanged. Version accepted for publication in Phys. Rev.
Strange resonance poles from scattering below 1.8 GeV
In this work we present a determination of the mass, width and coupling of
the resonances that appear in kaon-pion scattering below 1.8 GeV. These are:
the much debated scalar -meson, nowdays known as , the
scalar , the and vectors, the spin-two
as well as the spin-three . The parameters will be
determined from the pole associated to each resonance by means of an analytic
continuation of the scattering amplitudes obtained in a recent and
precise data analysis constrained with dispersion relations, which were not
well satisfied in previous analyses. This analytic continuation will be
performed by means of Pad\'e approximants, thus avoiding a particular model for
the pole parameterization. We also pay particular attention to the evaluation
of uncertainties.Comment: 13 pages, 12 figures. Accepted version to appear in Eur. Phys. J. C.
Clarifications and references added, minor typos correcte
scattering up to 1.47 GeV with hyperbolic dispersion relations
In this work we provide a dispersive analysis of scattering. For this purpose we present a set of partial-wave
hyperbolic dispersion relations using a family of hyperbolas that maximizes the
applicability range of the hyperbolic dispersive representation, which we have
extended up to 1.47 GeV. We then use these equations first to test simple fits
to different and often conflicting data sets, also showing that some of these
data and some popular parameterizations of these waves fail to satisfy the
dispersive analysis. Our main result is obtained after imposing these new
relations as constraints on the data fits. We thus provide simple and precise
parameterizations for the S, P and D waves that describe the experimental data
from threshold up to 2 GeV, while being consistent with crossing
symmetric partial-wave dispersion relations up to their maximum applicability
range of 1.47 GeV. For the -wave we have found that two solutions describing
two conflicting data sets are possible. The dispersion relations also provide a
representation for , and waves in the pseudo-physical region.Comment: 27 pages, 19 figures. Errata corrected and references added. Version
to appear in Eur. Phys. J.
Prosperity prospects in contested forest areas: evidence from community forestry development in Guatemala and Nicaragua
Tropentag, September 18-21, 2016, Vienna, Austria
“Solidarity in a competing world —
fair use of resources”
Prosperity Prospects in Contested Forest Areas: Evidence from
Community Forestry Development in Guatemala and Nicaragua
Dietmar Stoian
1
, Aldo Rodas
2
, Jessenia Arguello
3
1
Bioversity International, Healthy Diets from Sustainable Food Systems Initiative, France
2
Ministry of Agriculture and Livestock, Guatemala, Natural Resources and Agrotourism,
3
Independent Consultant,
Abstract
Community forestry is carried out under diverse institutional, environmental, and socio-economic
conditions. Local communities may have
de jure
rights to forest resources, but
de facto
protection
is often weak. This study focuses on 25-year community concessions in the Maya Biosphere Reserve
(MBR) in Guatemala and indigenous territories in the North Caribbean Coast Autonomous Region
(RACCN), Nicaragua. In both cases, communities are struggling to enforce their rights as powerful
external groups seek to expand cattle ranching, cash crops, tourism, and oil exploration. We found
evidence that community forestry can generate significant socio-economic benefits that, along with
contributions to forest conservation, substantiate the communities’ claim for strengthened and
extended community forest stewardship. We selected six community forest enterprises (CFEs) along
a business development gradient and assessed their context, economic viability, and livelihood
benefits among randomly selected CFE members (n=180). Adopting an asset lens, we determined
human, social, natural, physical and financial capital endowments at household and enterprise
levels. Enterprise assets varied widely, both within and across countries. CFEs were well endowed
with natural capital (7,000–54,000 ha of broadleaf forests) but highly dependent on precious woods,
such as mahogany (
Swietenia macropylla
) or andiroba (
Carapa guianensis
). Human capital was
sufficiently developed for managing forests, but less so for processing wood and doing business.
Social capital has been built in Guatemala through internal organisation, bringing CFEs under
the umbrella of a regional association, and developing relationships with buyers. In Nicaragua,
however, building of social capital has been insufficient for inducing a self-sustaining process of CFE
development. Physical capital for logging and wood processing was moderate but, in Guatemala,
conditions facilitate significant value adding. CFEs there were profitable, while those in the RACCN
struggled to break even. Household assets varied widely but, in the MBR, we found evidence that
forest-based income can lift people out of poverty. Our analyses reveal that critical success factors
for community forestry to reduce poverty, conserve forests and enhance equity are: secure long-term
forest usufruct rights or ownership, efficient business organisation, credible advocacy, a conducive
service environment, and differentiated opportunities for women, men and youth
Mineralogical Characterization and Ceramic Aplication of Muds From Washing of Natural Detritic Deposits
Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasFALSEpu
- …