2,518 research outputs found
Cambiando el paradigma: las narrativas del futuro guían el desarrollo de la INDC de Costa Rica
Este resumen de política presenta el proceso y los principales resultados del desarrollo de la INDC de Costa Rica a través de un proceso participativo en el que la construcción y uso de escenarios futuros fue el primer paso de un diálogo nacional para definir, probar y mejorar las medidas de mitigación para la reducción de las emisiones de gases de efecto invernadero
Shifting the paradigm: Narratives of the future guide the development of Costa Rica's INDC
This policy brief summarizes the process and main results of the development of Costa Rica´s INDC through a participatory process in which the building and use of future scenarios was the first step in a national dialogue to define, test and improve mitigation measures to lower emissions of greenhouse gases
Higher-order Mechanics: Variational Principles and other topics
After reviewing the Lagrangian-Hamiltonian unified formalism (i.e, the
Skinner-Rusk formalism) for higher-order (non-autonomous) dynamical systems, we
state a unified geometrical version of the Variational Principles which allows
us to derive the Lagrangian and Hamiltonian equations for these kinds of
systems. Then, the standard Lagrangian and Hamiltonian formulations of these
principles and the corresponding dynamical equations are recovered from this
unified framework.Comment: New version of the paper "Variational principles for higher-order
dynamical systems", which was presented in the "III Iberoamerican Meeting on
Geometry, Mechanics and Control" (Salamanca, 2012). The title is changed. A
detailed review is added. Sections containing results about variational
principles are enlarged with additional comments, diagrams and summarizing
results. Bibliography is update
Dynamic characterisation of interlaminar fracture toughness in carbon fibre epoxy composite laminates
In this work, the rate dependence of mode I interlaminar fracture toughness for two different materials systems,
IM7/8552 and IM7/M91, both unidirectional UD carbon-fibre epoxy composite laminates have been examined
over a wide range of loading rates from 0.5 mm/min up to 2000 mm/s at room temperature. Quasi-static fracture
tests were performed using a DCB (double-cantilever beam) method with a screw-driven testing machine, while
the dynamic tests were carried out using a WIF (wedge-insert fracture) specimen loaded dynamically in a hydraulic
system. For performing the tests at high displacement rates, a special setup was designed and manufactured
which allowed the insertion of the wedge within the DCB specimens at different cross-head displacement
rates. The experimental technique used a pair of strain gauges attached to the bending surface of one of the
arms of the cantilever beams and far from the initial crack tip. The peak values of the recorded strain were used
to determine the fracture toughness under dynamic conditions through use of the compliance calibration
method. A finite element model was developed to check the consistency of the measurements and validate the
data reduction method used. The results exhibited rate insensitive behaviour in the case of the IM7/8552 laminates
while IM7/M91 showed the contrary behaviour with maximum peak at 500 mm/s of displacement rate,
with a toughness increase of 95% with respect to the quasi-static conditions.The research leading to these results has received funding from the European Union as Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 722096, DYNACOMP project
Towards the periodization of the uses of Can Sadurní Cave (Begues, Catalonia) during the Middle Neolithic I. The contribution of bayesian modelling to radiocarbon dating sequences
Excavations at Can Sadurní Cave since 2012 have uncovered a complex stratigraphy for the Middle Neolithic phase (ca. 4700-4000 cal. BC). This was not in agreement with our expectations from the previous excavation of a trial trench, where only 4 layers (10, 10b,11 and 11b) were uncovered. After excavating a funerary layer with several in situ burials and further deposits containing multiple layers of burnt dung (fumier), the stratigraphy was revised and 5 episodes within layer 11 were detected. It became necessary to find a tool to refine the chronological sequence of these uses, under the premise that it is unlikely that the cave was used as a funerary area and a byre at the same time. Bayesian modelling allowed distinguishing these two phases, establishing an earlier use of the cave for animal herding purposes (ca. 4700-4450 cal. BC) and a funerary use of the cave in a more recent period (ca. 4400-4200 cal. BC)
Nonparametric analysis of casein complex genes' epistasis and their effects on phenotypic expression of milk yield and composition in Murciano-Granadina goats
Improving knowledge on the causative polymorphisms or genes regulating the expression of milk
quantitative and qualitative traits and their interconnections plays a major role in dairy goat breeding programs and genomic research. This information enables
optimization of predictive and selective tools, to obtain better-performing animals to help satisfy market
demands more efficiently. Goat milk casein proteins
(αS1, αS2, β, and κ) are encoded by 4 loci (CSN1S1,
CSN1S2, CSN2, and CSN3) clustered within 250 kb on
chromosome 6. Among the statistical methods used to
identify epistatic interactions in genome-wide qualitative association studies (GWAS), gene-based methods
have recently grown in popularity due to their better
statistical power and biological interpretability. However, most of these methods make strong assumptions
about the magnitude of the relationships between SNP
and phenotype, limiting statistical power. Thus, the
aims of this study were to quantify the epistatic relationships among 48 SNP in the casein complex on the
expression of milk yield and components (fat, protein,
dry matter, lactose, and somatic cells) in MurcianoGranadina goats, to explain the qualitative nature
of the SNP used to quantify the genotypes produced
as a result. Categorical principal component analysis
(CATPCA) was used to delimit and group the number
of SNP studied depending on their implications in the
explanation of milk yield and components variability.
Afterward, nonlinear canonical correlation analysis was
used to identify relationships among and within the
SNP groups detected by CATPCA. Our results suggest
that 79.65% of variability in the traits evaluated may
be ascribed to the epistatic relationships across and
within 7 SNP groups. Two partially overlapping groups
of epistatically interrelated SNP were detected: one
group of 21 SNP, explaining 57.56% of variability, and
another group of 20 SNP, explaining 42.43% (multiple
fit ≥ 0.1). Additionally, SNP18, 32, and 36 (CSN1S2,
CSN1S1, and CSN2 loci, respectively) were the most
significant SNP to explain intragroup epistatic variability (component loading > |0.5|). Conclusively, milk
yield and quality may not only depend on the specific
casein gene pool of individuals, but may also be relevantly conditioned by the relationships set across and
within such genes. Hence, studying epistasis in isolation may be crucial to optimize selective practices for
economically important dairy traits
Rectificación a la primera cita de Flebotomos (Diptera, Psychodidae) en la Península Ibérica
Not availableNo disponibl
Revisión de la colección Nájera de Flebotomos (Diptera, Psychodidae) depositada en el Museo Nacional de Ciencias Naturales de Madrid
Not availableNo disponibl
Discrete Nonholonomic Lagrangian Systems on Lie Groupoids
This paper studies the construction of geometric integrators for nonholonomic
systems. We derive the nonholonomic discrete Euler-Lagrange equations in a
setting which permits to deduce geometric integrators for continuous
nonholonomic systems (reduced or not). The formalism is given in terms of Lie
groupoids, specifying a discrete Lagrangian and a constraint submanifold on it.
Additionally, it is necessary to fix a vector subbundle of the Lie algebroid
associated to the Lie groupoid. We also discuss the existence of nonholonomic
evolution operators in terms of the discrete nonholonomic Legendre
transformations and in terms of adequate decompositions of the prolongation of
the Lie groupoid. The characterization of the reversibility of the evolution
operator and the discrete nonholonomic momentum equation are also considered.
Finally, we illustrate with several classical examples the wide range of
application of the theory (the discrete nonholonomic constrained particle, the
Suslov system, the Chaplygin sleigh, the Veselova system, the rolling ball on a
rotating table and the two wheeled planar mobile robot).Comment: 45 page
Near-Earth asteroids spectroscopic survey at Isaac Newton Telescope
The population of near-Earth asteroids (NEAs) shows a large variety of
objects in terms of physical and dynamical properties. They are subject to
planetary encounters and to strong solar wind and radiation effects. Their
study is also motivated by practical reasons regarding space exploration and
long-term probability of impact with the Earth. We aim to spectrally
characterize a significant sample of NEAs with sizes in the range of 0.25
- 5.5 km (categorized as large), and search for connections between their
spectral types and the orbital parameters. Optical spectra of NEAs were
obtained using the Isaac Newton Telescope (INT) equipped with the IDS
spectrograph. These observations are analyzed using taxonomic classification
and by comparison with laboratory spectra of meteorites. A total number of 76
NEAs were observed. We classified 44 of them as Q/S-complex, 16 as B/C-complex,
eight as V-types, and another eight belong to the remaining taxonomic classes.
Our sample contains 27 asteroids categorized as potentially hazardous and 31
possible targets for space missions including (459872) 2014 EK24, (436724) 2011
UW158, and (67367) 2000 LY27. The spectral data corresponding to (276049) 2002
CE26 and (385186) 1994 AW1 shows the 0.7 m feature which indicates the
presence of hydrated minerals on their surface. We report that Q-types have the
lowest perihelia (a median value and absolute deviation of AU)
and are systematically larger than the S-type asteroids observed in our sample.
We explain these observational evidences by thermal fatigue fragmentation as
the main process for the rejuvenation of NEA surfaces. In general terms, the
taxonomic distribution of our sample is similar to the previous studies and
matches the broad groups of the inner main belt asteroids. Nevertheless, we
found a wide diversity of spectra compared to the standard taxonomic types.Comment: Accepted in Astronomy & Astrophysics (A&A
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