902 research outputs found
Anthropometric Dimensions and Bone Quality in International Male Beach Handball Players: Junior vs. Senior Comparison
Background: Beach handball is a recent team sport characterized by defensive and offensive actions on a sand surface. Scientific evidence has shown that body composition is fundamental in sports performance. The main objective of this study was to know the body composition, anthropometric characteristics, and bone mineral density of elite beach handball players. Furthermore, another purpose was to analyze the differences between categories (junior and senior) and playing position. Methods: A descriptive, cross-sectional study of 36 male players (18 juniors and 18 seniors) of the Spanish National Beach Handball Team was conducted. Full profile anthropometry and calcaneal ultrasound measurements were used. Results: Significant differences between categories (p < 0.05) were found in: height, body mass, arm span, BMI, muscle mass, fat mass, bone mass, skinfolds, and body perimeters. The somatotype changes depending on the playing position. Bone mineral density of the players was adequate. No significant differences were found by playing position. Conclusions: Senior players had a better body composition due to the presence of less fat mass than junior players. This study provides reference values of elite junior and senior beach handball players and by playing positions. This data is useful for the identification of talents and players who should be trained to improve their body composition
Effects of salinity and B excess on the growth, photosynthesis, water relation and mineral composition of laurustinus grown in greenhouse
Trabajo presentado en el XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Greenhouse 2010 and Soilless Cultivation, celebrado en Lisboa, Portugal, del 22 al 27 de agosto de 2010A greenhouse study was conducted to determine the interactive effects of NaCl
salinity and boron on the growth, plant water status, gas exchange, chlorophyll
fluorescence and concentrations of sodium (Na), chloride (Cl) and boron (B) in
laurustinus (Viburnum tinus L.). Potted plants were grown in a factorial
combination of salinity (2 and 6 dS m-1) and boron (1 and 6 mg L-1). Plant dry
weight (DW) decreased with salinity and B excess, particularly as a result of the
former. The salinity × B interaction on the plant DW was not significant (additive
effects). Salinity increased Na and Cl concentrations in leaf (20 and 35 mg g-1 DW,
respectively) resulting in foliar injury. The application of 6 mg L-1 of B (B toxicity or
B excess) produced injury symptoms in old leaves (leaf tip and edge burn). Salinity
and B toxicity led to leaves dropping, especially the former. B toxicity led to higher B
concentrations in insured leaves (1385 mg kg-1 DW) and salinity reduced it to 425 (B
x NaCl antagonistic effect). Boron excess did no alter Na and Cl concentrations in
leaf. Salinity decreased stomatal conductance (gs) as a regulatory mechanism against
osmotic stress, which resulted in a dropping photosynthesis (Pn). Leaf water
parameters were only affected by salinity, which enhanced a process of osmotic
adjustment and improving the plant water status. Salt-stressed plants showed an
adaptive response to salinity, which decreased gs, Pn and quantum yield of
photosystem II (éPSII), and dissipated the excess radiant energy as heat (increased
non-photochemical quenching [NPQ]). The combination of salinity and B excess
maintained éPSII and decreased the effectiveness of stomatal regulation, NPQ and
Pn. This caused the lowest plant DW and suggests disorders in electron transport
(photorespiration). Our findings suggest that: (1) laurustinus is a B excess sensitive
species, (2) salinity reduced the accumulation of B in leaves of the B excess stressed
plants but was not enough to prevent injuries in PSII, and (3) B excess or/and
salinity provide plants of poor commercial quality.This research was supported by CICYT projects (CICYT AGL2008-05258-CO2-
1-AGR and CICYT AGL2008-05258-CO2-2-AGR), SENECA project (08669/PI/08) and
by the Consejería de Agricultura y Agua de la Región de Murcia, program (UPCTCEBAS-
IMIDA 2008).Peer Reviewe
Impact of EV penetration in the interconnected urban environment of a smart city
The smart city seeks a highly interconnected, monitored and globally optimized environment to profit from the synergies among systems such as energy, transports or waste management. From an energy perspective, transport systems and facilities are among the bigger energy consumers inside cities. However, despite the research available on such systems, few works focus on their interactions and potential synergies to increase their efficiencies. This paper address this problem by assessing the benefits of the interconnection and joint management of different energy systems in a smart city context. This is done using a linear programming problem, modelling a district with residential loads, distributed energy resources (DER) and electric vehicles (EV), which are also connected to an electrical metro substation. This connection allows to store the metro regenerative braking energy into EVs' batteries to be used later for other trains or for the EVs themselves. The objective of the linear programming model is to find the optimal planning and operation of all the considered systems, achieving minimum energy costs. Therefore, the main contributions of this paper are the assessment of synergies of the interconnection of these systems and the detailed analysis of the impact of different EV penetration levels. Results show important economic benefits for the overall system (up to 30%) when the investments and its operation are globally optimized, especially reducing the metro energy costs. Also, analysing the energy transfers between metro-EV, it is evident that the metro takes advantages of the cheaper energy coming from the district (through the EVs), showing the existence of "opportunistic" synergies. Lastly, EV saturation points (where extra EVs represent more load but do not provide additional useful storage to the system) can be relatively small (200–300 EVs) when the energy transfer to the metro electrical substation is restricted, but it is also reduced by the presence of DER systems
Storage and demand response contribution to firm capacity: Analysis of the Spanish electricity system
Provision of firm capacity will become a challenge in power systems dominated by renewable generation. This paper analyzes the competitiveness and role of battery storage, six types of pumped-hydro storage, open cycle gas turbine (OCGT), and demand response (DR) technologies in providing the firm capacity required to guarantee the security of supply in a real-size power system such as the Spanish one in horizon 2030. The paper contributes with detailed and realistic modeling of the DR capabilities. Demand is disaggregated by sector and activities and projected towards 2030, applying a growth rate by activity. The load flexibility constraints are considered to ensure the validity of the results. A generation operation planning and expansion model, SPLODER, is conveniently upgraded to properly represent the different storage alternatives addressed in the paper. The results highlight the importance of considering demand response for evaluating long-term firm capacity requirements, showing a non-negligible impact on the investment decisions on the amount of firm capacity required in the system and the optimal shares of wind and solar PV renewable generation. Results also show the dominance of cost-competitiveness of pumped hydro and OCGTs over batteries. Additionally, capacity payments are required to support firm capacity providers’ investments. © 2022This research has been carried out thanks to the Iberdrola Chair on Energy and Innovation and the funding of the RETOS COLABORACIÓN program of the Spanish Ministry of Science and Innovation and the Spanish State Research Agency (project “Platform of innovative models to accelerate the energy decarbonization of the economy (MODESC)”, with reference number RTC2019-007315-3 ). This research is also supported by the Spanish Ministry of Economy and Competitiveness MINECO through BC3 María de Maeztu excellence accreditation MDM-2017-0714
Potential of MMP-9 based nanoparticles at optimizing the cow dry period: pulling apart the effects of MMP-9 and nanoparticles
The cow dry period is a non-milking interval where the mammary gland involutes and regenerates
to guarantee an optimal milk production in the subsequent lactation. Important bottlenecks such
as the high risk of intramammary infections complicate the process. Antibiotics have been routinely
used as a preventive treatment but the concerns about potential antibiotic resistance open a new
scenario in which alternative strategies have to be developed. Matrix metalloproteinase-9 (MMP-9) is
an enzyme able to degrade the extracellular matrix, triggering the involution and immune function of
cow mammary gland. We have studied the infusion into the mammary gland of MMP-9 inclusion bodies
as protein-based nanoparticles, demonstrating that 1.2 mg of MMP-9 enhanced the involution and
immune function of the cow mammary gland. However, the comparison of the efects triggered by the
administration of an active and an inactive form of MMP-9 led to conclude that the response observed
in the bovine mammary gland was mainly due to the protein format but not to the biological activity of
the MMP-9 embedded in the inclusion body. This study provides relevant information on the future use
of protein inclusion bodies in cow mammary gland and the role of MMP-9 at dry-of.info:eu-repo/semantics/publishedVersio
First survey of Wolf-Rayet star populations over the full extension of nearby galaxies observed with CALIFA
The search of extragalactic regions with conspicuous presence of Wolf-Rayet
(WR) stars outside the Local Group is challenging task due to the difficulties
in detecting their faint spectral features. In this exploratory work, we
develop a methodology to perform an automated search of WR signatures through a
pixel-by-pixel analysis of integral field spectroscopy (IFS) data belonging to
the Calar Alto Legacy Integral Field Area survey, CALIFA. This technique
allowed us to build the first catalogue of Wolf-Rayet rich regions with
spatially-resolved information, allowing to study the properties of these
complexes in a 2D context. The detection technique is based on the
identification of the blue WR bump (around He II 4686 {\AA}, mainly associated
to nitrogen-rich WR stars, WN) and the red WR bump (around C IV 5808 {\AA} and
associated to carbon-rich WR stars, WC) using a pixel-by-pixel analysis. We
identified 44 WR-rich regions with blue bumps distributed in 25 galaxies of a
total of 558. The red WR bump was identified only in 5 of those regions. We
found that the majority of the galaxies hosting WR populations in our sample
are involved in some kind of interaction process. Half of the host galaxies
share some properties with gamma-ray burst (GRB) hosts where WR stars, as
potential candidates to being the progenitors of GRBs, are found. We also
compared the WR properties derived from the CALIFA data with stellar population
synthesis models, and confirm that simple star models are generally not able to
reproduce the observations. We conclude that other effects, such as the binary
star channel (which could extend the WR phase up to 10 Myr), fast rotation or
other physical processes that causes the loss of observed Lyman continuum
photons, are very likely affecting the derived WR properties, and hence should
be considered when modelling the evolution of massive stars.Comment: 33 pages, accepted for publication in A&
The O3N2 and N2 abundance indicators revisited: improved calibrations based on CALIFA and Te-based literature data
The use of IFS is since recently allowing to measure the emission line fluxes
of an increasingly large number of star-forming galaxies both locally and at
high redshift. The main goal of this study is to review the most widely used
empirical oxygen calibrations, O3N2 and N2, by using new direct abundance
measurements. We pay special attention to the expected uncertainty of these
calibrations as a function of the index value or abundance derived and the
presence of possible systematic offsets. This is possible thanks to the
analysis of the most ambitious compilation of Te-based HII regions to date.
This new dataset compiles the Te-based abundances of 603 HII regions extracted
from the literature but also includes new measurements from the CALIFA survey.
Besides providing new and improved empirical calibrations for the gas
abundance, we also present here a comparison between our revisited calibrations
with a total of 3423 additional CALIFA HII complexes with abundances derived
using the ONS calibration by Pilyugin et al. (2010). The combined analysis of
Te-based and ONS abundances allows us to derive their most accurate calibration
to date for both the O3N2 and N2 single-ratio indicators, in terms of all
statistical significance, quality and coverage of the space of parameters. In
particular, we infer that these indicators show shallower abundance
dependencies and statistically-significant offsets compared to those of Pettini
and Pagel (2004), Nagao et al. (2006) and P\'erez-Montero and Contini (2009).
The O3N2 and N2 indicators can be empirically applied to derive oxygen
abundances calibrations from either direct abundance determinations with random
errors of 0.18 and 0.16, respectively, or from indirect ones (but based on a
large amount of data) reaching an average precision of 0.08 and 0.09 dex
(random) and 0.02 and 0.08 dex (systematic; compared to the direct
estimations),respectively.Comment: 12 pages, 5 figures, accepted for publication in A&
Insights onto the magnetic coupling at hexaferrite-based hard/soft bilayer systems
IBERTRIVA 2019 X Iberian Conference on Tribology – IBERTRIB, XI Iberian Vacuum Conference - RIVA, Seville, Spain,June 26-28Magnets are used in a variety of applications, such as generators, magnetic recording media,
components in RF and microwave devices. However, many of these magnets contain s rare
earths, critical elements whose extraction is environmentally harmful and that present price
volatility risks. Their replacement by cheaper and more environmentally friendly materials is
therefore sought.
In our case, we have focused on magnetically hard strontium hexaferrite (SrFe 12O19, SFO) as
the base for alternative permanent magnets (Figure 1a). The atomic arrangement of this ferrite
results in a high magnetocrystalline anisotropy and a coercive field, however, its magnetization
is moderate (1). It is well known that the coupling between a magnetically hard and soft material
improved magnetization while avoiding a high cost in coercitivity loss (2). However, results have
been disappointing so far as structural and geometrical limitations make it extremely challenging
to fabricate. In this work, we aim at further understanding the magnetic coupling at hard -soft
interfaces involving ferrites, for which we have deposited soft iron and cobalt metals on top of
SrFe12O19 thin films with controlled easy-axis of magnetization.
SFO thin films have been obtained by RF magnetron sputtering at 260W followed by a
subsequent annealing in air of 850ºC. Their structure and composition was characterized by
Raman spectroscospy (Figure 1b), Mössbauer spectroscopy, X-ray photoemission
spectroscopy and low-energy electron microscopy (LEEM). We have grown the magnetically
soft layer by molecular-beam epitaxy and we have analyzed the resulting bilayer system
through photoemission electron microscopy, LEEM and vibrating-sample magnetometry.
References
[1] R.C. Pullar, Hexagonal ferrites: a review of the synthesis, properties and applications of hexaferrite ceramics, Progress in Materials Science 57 (2012), pp 1191¿1334.
[2] Eric E. Fullerton, J. S. Jiang, M. Grimsditch, C. H. Sowers, and S. D. Bader, Exchange-spring behavior in epitaxial hard/soft magnetic bilayers, Phys. Rev. B 58 (1998) 1219
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