11,678 research outputs found
Sustainable Planning of Land Use Changes in farming areas under ecological protection
Land use has been changing in the last decades because of agricultural intensification and land abandonment which implies deterioration in the optimum habitat structure and quality. Habitat degradation and loss, resulting from changes in land use remain significant drivers of biodiversity loss. These trends are widely recognised and have forced national and international agencies to identify protected sites for natural areas with high biodiversity value. Special Protection Areas (SPAs) are natural zones particularly relevant for nature conservation. Regional planning is bound to play an increasing role in nature conservation policies because much biodiversity is located in farming areas outside natural parks. Agriculture in the Mediterranean Basin has always been highly dependent on rainfed crops, cereal, vine and olive. Vine growing plays an important role not only from the economic point of view, but also environmentally as a permanent plant cover in terms of preventing erosion, managing land and water resources in a sustainable way, defending against desertification an settling population in rural areas. A Geographic Information System (GIS) was used to implement a decision tool system to analyse the feasibility of new proposals to upgrade traditional vineyards in Castilla-La Mancha, Spain. The study focuses on the sustainability of current farming practices in Special Protection Areas for Steppe Land Birds. This paper presents a model to quantify the resulting habitat fragmentation basing on infrastructure facilities, leading to mapping areas where to apply restriction measures to prevent physical destruction of the habita
An empirical calibration of nebular abundances based on the sulphur emission lines
We present an empirical calibration of nebular abundances based on the strong
emission lines of [SII] and [SIII] in the red part of the spectrum through the
definition of a sulphur abundance parameter S23. This calibration presents two
important advantages against the commonly used one based on the optical oxygen
lines: it remains single-valued up to abundances close to solar and is rather
independent of the degree of ionization of the nebula.Comment: 10 pages, 8 figures. Accepted for publication in MNRA
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The Temporal Efficiency of SO2 Emissions Trading
The Temporal Efficiency of SO2 Emissions Tradin
Measuring the black hole spin direction in 3D Cartesian numerical relativity simulations
We show that the so-called flat-space rotational Killing vector method for
measuring the Cartesian components of a black hole spin can be derived from the
surface integral of Weinberg's pseudotensor over the apparent horizon surface
when using Gaussian normal coordinates in the integration. Moreover, the
integration of the pseudotensor in this gauge yields the Komar angular momentum
integral in a foliation adapted to the axisymmetry of the spacetime. As a
result, the method does not explicitly depend on the evolved lapse and
shift on the respective timeslice, as they are fixed to Gaussian
normal coordinates, while leaving the coordinate labels of the spatial metric
and the extrinsic curvature unchanged. Such gauge fixing
endows the method with coordinate invariance, which is not present in integral
expressions using Weinberg's pseudotensor, as they normally rely on the
explicit use of Cartesian coordinates
FCNC in the minimal 3-3-1 model revisited
We show that in the minimal 3-3-1 model the flavor changing neutral currents
(FCNCs) do not impose necessarily strong constraints on the mass of the
of the model if we also consider the neutral scalar contributions to
such processes, like the neutral mesons mass difference and rare semileptonic
decays. We first obtain numerical values for all the mixing matrices of the
model i.e., the unitary matrices that rotate the left- and right-handed quarks
in each charge sector which give the correct mass of all the quarks and the CKM
mixing matrix. Then, we find that there is a range of parameters in which the
neutral scalar contributions to these processes may interfere with those of the
, implying this vector boson may be lighter than it has been thought.Comment: Extended version including the effect of a pseudoscalar. 37 pags. and
12 figures. New references added. Version matches the published versio
Trumpet Slices in Kerr Spacetimes
We introduce a new time-independent family of analytical coordinate systems
for the Kerr spacetime representing rotating black holes. We also propose a
(2+1)+1 formalism for the characterization of trumpet geometries. Applying this
formalism to our new family of coordinate systems we identify, for the first
time, analytical and stationary trumpet slices for general rotating black
holes, even for charged black holes in the presence of a cosmological constant.
We present results for metric functions in this slicing and analyze the
geometry of the rotating trumpet surface.Comment: 5 pages, 2 figures; version published in PR
Calorons on the lattice - a new perspective
We discuss the manifestation of instanton and monopole solutions on a
periodic lattice at finite temperature and their relation to the infinite
volume analytic caloron solutions with asymptotic non-trivial Polyakov loops.
As a tool we use improved cooling and twisted boundary conditions. Typically we
find 2Q lumps for topological charge Q. These lumps are BPS monopoles.Comment: Latex. 16 pages, 9 figure
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