926 research outputs found
S wave velocity structure below central Mexico using high-resolution surface wave tomography
Shear wave velocity of the crust below central Mexico is estimated using surface wave dispersion measurements from regional earthquakes recorded on a dense, 500 km long linear seismic network. Vertical components of regional records from 90 well-located earthquakes were used to compute Rayleigh-wave group-velocity dispersion curves. A tomographic inversion, with high resolution in a zone close to the array, obtained for periods between 5 and 50 s reveals significant differences relative to a reference model, especially at larger periods (>30 s). A 2-D S wave velocity model is obtained from the inversion of local dispersion curves that were reconstructed from the tomographic solutions. The results show large differences, especially in the lower crust, among back-arc, volcanic arc, and fore-arc regions; they also show a well-resolved low-velocity zone just below the active part of the Trans Mexican Volcanic Belt (TMVB) suggesting the presence of a mantle wedge. Low densities in the back arc, inferred from the low shear wave velocities, can provide isostatic support for the TMVB
Beet silage: chemical composition, fermentacion parameters and use of NIRS Technology as a tool to identify ensiled beet varieties
8 páginas, 2 figuras, 4 tablas.--Comunicación presentada a la 53ª Reunión Científica de la Sociedad Española para el Estudio de los Pastos (SEEP). "Pastos y PAC 2014-2020"[EN] The use of beet root for the purpose of feeding the dairy
cattle could be constrained by the scarce knowledge
about the characteristics of this feed after it has been
ensiled. To investigate the feasibility of using the NIRS
methodology to analyze the chemical composition of
ensiled beets and to discriminate between beet varieties,
roots of four beet varieties were ensiled (Sandrina KWS
1193, Tilly KWS 2733, Gerty KWS 2734 and Páramo
3359) using laboratory silos (600 ml of capacity).
Although small differences (P<0.05) in chemical
composition were found between treatments, the range
of variation was narrow, especially for crude protein,
which reached low and quite uniform values. The pH
values were lower than 4 for all the varieties and the
fermentation was mainly acetic. Whereas NIRS spectra
of raw silages did not allow beet varieties discrimination
or chemical composition prediction, spectra from dried
and milled samples suggest that NIRS technology could
be used as a tool for both purposes. NIRS spectra of
silage juices could also be useful to establish beet variety.[ES] El empleo de raíces de remolacha en la alimentación del
vacuno de leche se ve limitado por el escaso
conocimiento acerca de las características de este
alimento una vez ensilado. Para estudiar la composición
química y los principales parámetros de fermentación de
ensilados de remolacha y explorar la posibilidad de
emplear la tecnología de espectroscopía de reflectancia
en el infrarrojo cercano (NIRS) para la estimación de los
parámetros estudiados y para discriminar distintas
variedades de remolacha, se ensilaron raíces de cuatro
variedades de remolacha (Sandrina KWS 1193, Tilly
KWS 2733, Gerty KWS 2734 y Páramo 3359)
empleando micro-silos de 600 ml de capacidad. Se
detectaron diferencias (P<0,05) entre variedades en
todos los parámetros de composición química de los
ensilados, aunque en el caso de la proteína sólo la
variedad Tilly KWS 2733 presentó un contenido
diferente (P<0,05) a los del resto de las variedades. El
pH alcanzó valores menores que 4 para todas las
variedades y la fermentación fue principalmente acética.
Los espectros NIRS de las muestras de ensilado en
fresco no permitieron ni discriminar entre las variedades
ensiladas ni predecir la composición química. Sin
embargo, los resultados con las muestras secas y molidas
sí apuntan la posibilidad de emplear la tecnología NIRS
con ambos fines. Los espectros NIRS de los jugos del
ensilado también podrían resultar útiles para establecer
la variedad de remolacha ensilada.Este trabajo se financió con el contrato
asociado a proyecto CDTI titulado: Procesado
y estudio de variedades de remolacha para
su utilización en alimentación animal (código
100102120005). Organismo financiador: INDUSTRIAS
DE NUTRICIÓN ANIMAL, S.L.Peer reviewe
Effects of climate, species interactions, and dispersal on decadal colonization and extinction rates of Iberian tree species
We studied the relative importance of climate, abundance of potentially competing species, and dispersal in explaining local colonization and extinction rates of tree species throughout mainland Spain. We used a Bayesian framework to parameterize a patch occupancy model to 23 species censused in 46,596 permanent plots in a 1 × 1 km grid across most Spanish forests. For most species, dispersal was the single best predictor of colonization, whereas climate and dispersal were equally important as predictors of extinction. Precipitation was positively correlated with the colonization rate of 12 out of 13 deciduous broad-leaved species, and negatively correlated with the extinction rate of nine of them. In contrast, precipitation equally decreased colonization and extinction of five out of eight of needle-leaved species (Juniperus and Pinus spp.). There was, however, marked variation among species in the magnitude of these effects, with some species exhibiting contrasting patterns for the colonization and the extinction process. Abundance of competing tree species (= summed plot basal area) was consistently correlated with decreased colonization of all needle-leaved species, and it increased the extinction rate of 6 out of 8 of these species. It had, nonetheless, weak facilitative effect on some broad-leaved species by promoting colonization (3 of 13 species) and decreasing extinction (7 of 13 species). With local colonization and extinction data, non-equilibrial and dynamic species distribution modelling can be improved by incorporating measures of biotic interactions and dispersal effects, along with traditional climate variables.Ministerio de Economía y CompetitividadComunidad de Madri
Effects of climate, species interactions, and dispersal on decadal colonization and extinction rates of Iberian tree species
We studied the relative importance of climate, abundance of potentially competing species, and dispersal in explaining local colonization and extinction rates of tree species throughout mainland Spain. We used a Bayesian framework to parameterize a patch occupancy model to 23 species censused in 46,596 permanent plots in a 1 × 1 km grid across most Spanish forests. For most species, dispersal was the single best predictor of colonization, whereas climate and dispersal were equally important as predictors of extinction. Precipitation was positively correlated with the colonization rate of 12 out of 13 deciduous broad-leaved species, and negatively correlated with the extinction rate of nine of them. In contrast, precipitation equally decreased colonization and extinction of five out of eight of needle-leaved species (Juniperus and Pinus spp.). There was, however, marked variation among species in the magnitude of these effects, with some species exhibiting contrasting patterns for the colonization and the extinction process. Abundance of competing tree species (= summed plot basal area) was consistently correlated with decreased colonization of all needle-leaved species, and it increased the extinction rate of 6 out of 8 of these species. It had, nonetheless, weak facilitative effect on some broad-leaved species by promoting colonization (3 of 13 species) and decreasing extinction (7 of 13 species). With local colonization and extinction data, non-equilibrial and dynamic species distribution modelling can be improved by incorporating measures of biotic interactions and dispersal effects, along with traditional climate variables.Ministerio de Economía y CompetitividadComunidad de Madri
Biosynthesis of Antitumoral and Bactericidal Sanguinarine
A simple, rapid, and reliable TLC method for the separation and determination of sanguinarine has been established. This intensively studied biologically active alkaloid has a wide range of potentially useful medicinal properties, such as antimicrobial, antiinflammatory, and antitumoral activities. Sanguinarine has also been incorporated into expectorant mixtures and has a strong bactericidal effect upon gram-positive bacteria, particularly Bacillus anthracis and staphylococci. These medicinal properties are due to the interaction of sanguinarine with DNA. A fibre-optic-based fluorescence instrument for in situ scanning was used for quantitative measurements. The sanguinarine was determined over the range 5–40 ng and a detection limit of 1.60 ng. The method was applied to the quantification of sanguinarine in tissue culture extracts of Chelidonium majus L
Pseudoaneurisma de la arteria geniculada superior lateral secundaria a artroplastia de rodilla: Aportación de un caso
El pseudoaneurisma es una complicación infrecuente en la cirugía ortopédica de rodilla. Los pocos casos descritos generalmente están en relación con cirugía artroscópica. Presentamos un caso de pseudoaneurisma de la arteria geniculada superolateral secundario a artroplastia de rodilla en un varón de 69 años. El diagnóstico se realizó mediante arteriografía. Se trató con éxito mediante hemostasia y resección química.Pseudoaneurysm is an uncommon complication in knee orthopaedic surgery. There are few cases reported an most of them are secondary to arthroscopic techniques. We report a case of pseudoaneurysm of the superolateral genicular artery after knee arthroplasty in a 69-year-old-man. The diagnosis was made with arteriographay, and treatment was a successful hemostasia and surgical resection
Evaluating the combined effects of climate and land-use change on tree species distributions
A large proportion of the world's biodiversity is reportedly threatened by habitat loss and climate change. However, there are few studies that investigate the interaction between these two threats using empirical data.Here, we investigate interactions between climate change and land use change in the future distribution of 23 dominant tree species in mainland Spain. We simulated changes up to year 2100 using a climate-dependent Stochastic Patch Occupancy Model, parameterized with colonization and extinction events recorded in 46 569 survey plots.We estimated that the distribution of 17 out of 23 tree species are expanding, and hence not at equilibrium with the climate. However, climate change will make the future occupancy of 15 species lower than expected if climate, and habitat, remained stable (baseline scenario).Climate change, when combined with 20% habitat loss, was estimated to reduce species occupancy by an average of 23% if habitat loss is spatially clumped, relative to baseline projections, and by 35% if scattered. If habitat loss occurred in areas already impacted by human activities, species occupancy would be reduced by 26%. Land-use changes leading to habitat gain (i.e. creation through e.g. reforestation), could slightly mitigate the effects of climate change; but a 20% increment in habitat would reduce climate-change-driven losses in species occupancy by only ~3%.Synthesis and applications. The distributions of the most common tree species in mainlandSpain are expanding, but climate change threatens to reduce this expansion by 18% for 15of the 23 studied species. Moreover, if the habitat of these species is simultaneously lost, theoccupancies of all of them will be reduced further, with variation depending on the spatialpattern of the lost habitats. However, we did not detect synergies between climate change andhabitat loss. The combined effect (with 20% habitat loss) was 5–13% less than what it wouldbe if the effects were additive. Importantly, reforestation could partially offset the negativeeffects of climate change, but complete mitigation would require an increase in forested landof 80%, and the prioritization of territories that are less impacted by human activities.Ministerio de Economía y CompetitividadComunidad de Madri
Fibrohistiocitoma maligno óseo tras degeneración de enfermedad de Paget Caso clínico y revisión de la literatura
El fibrohistiocitoma maligno óseo es un tumor de estirpe mesenquimal poco frecuente,
pero de alta agresividad. Se suele presentar de forma primaria, aunque a veces lo hace sobre
lesiones previas en el hueso. Puede ser difícil de diferenciar histológicamente de otros tumores,
pero es una entidad propia desde el punto de vista anatomopatológico. Presentamos un paciente
con enfermedad de Paget que desarrolló un fibrohistiocitoma maligno óseo en el fémur
sobre el hueso pagético. Fue tratado mediante desarticulación de cadera. No se usó quimioterapia
como tratamiento coadyuvante debido a su avanzada edad y situación basal. A los 18 meses se
encuentra asintomático y sin signos de recurrencia. Se hace una revisión de la literatura acerca
de este tumor.Malignant fibrous histiocytoma of bone is a rare but highly agressive mesenchimal
tumor. It usually arises as a primary tumor but sometimes it can be associated with pre-existing bone
abnormalities. Histologically it can be missdiagnosed with other tumors. We report a case of malignant
fibrous histiocytoma of bone in the femur in a patient with Paget's disease treated by hip
desarticulation. We didn't use chemotherapy because his elderly status. At 18 months follow up, the
patient is symptom-free and neither local recurrence nor metastasis have been found. A review of
the literature has been carried out
Energy loss of H+ and H2+ beams in carbon nanotubes: a joint experimental and simulation study
Carbon nanotube properties can be modified by ion irradiation; therefore it is important to know the manner in which ions deposit energy (how much and where) in the nanotubes. In this work, we have studied, experimentally and with a simulation code, the irradiation of multi-walled carbon nanotubes (MWCNT), supported on a holey amorphous carbon (a-C) substrate, with low energy (2–10 keV/u) H+ and H2+ molecular beams, impinging perpendicularly to the MWCNT axis. The energy distribution of protons traversing the nanotubes (either from the H+ beam or dissociated from the H2+ beam) was measured by the transmission technique in the forward direction. Two well-differentiated peaks appear in the experimental energy-loss distribution of the fragments dissociated from the molecular H2+ beam, in correspondence to the ones detected with the proton beam. One is the low-energy loss peak (LELP), which has a symmetric width; the other is the high-energy loss peak (HELP), which shows an asymmetric broadening towards larger energy loss than the corresponding proton energy distribution. A semi-classical simulation, accounting for the main interaction processes (both elastic and inelastic), of the proton trajectories through the nanotube and the supporting substrate has been done, in order to elucidate the origin of these structures in the energy spectra. Regarding the H+ energy spectrum, the LELP corresponds to projectiles that travel in quasi-channelling motion through the most outer walls of the nanotubes and then pass through the substrate holes, whereas the HELP results mostly from projectiles traversing only the a-C substrate, with the asymmetry broadening being due to a minor contribution of those protons that cross the a-C substrate after exiting the nanotube. The broadening of the peaks corresponding to dissociated fragments, with respect to that of the isolated protons, is the result of vicinage effects between the fragments, when travelling in quasi-channelling conditions through the outer layers of the nanotube, and Coulomb explosion just after exiting the target. The excellent agreement between the measured and the simulated energy spectra of the H+ beam validates our simulation code in order to predict the energy deposited by ion beams in carbon nanotubes.This work has been financially supported by Fondecyt 1100759, Fondecyt 1121203 and USM-DGIP 11.11.11, Anillo ACT1108, Proyecto Basal FB0821 - CONICYT, the Spanish Ministerio de Economía y Competitividad and European Regional Development Fund (Projects FIS2014-58849-P and PGC2018-096788-B-I00), and Fundación Séneca (Project No. 19907/GERM/15)
Impact assessment of agricultural inputs into a Mediterranean coastal lagoon (Mar Menor, SE)
The Mar Menor is a coastal lagoon threatened by the development of intensive agriculture in
the surrounding areas. Large amounts of pesticides from these areas are discharged into El Albujón, a
permanent watercourse flowing into the lagoon.
We have used a multi-biomarker approach to assess the biological effects arising in bivalve species
affected by agricultural pollution. Biomarkers indicative of neurotoxicity (acetylcholinesterase, AchE),
oxidative stress (catalase, CAT; glutathione reductase, GR and lipid peroxidation, LPO), phase II
biotransformation of xenobiotics (glutathione S-transferase, GST) and physiological stress (scope for
growth, SFG) were measured in clams transplanted to four sites of the lagoon (two reference sites and
two sites affected by the dispersion of the effluent of the El Albujón), for exposure periods of 7 and 22
days.
The hazards of this effluent were also examined by simultaneously measuring up to 83 contaminants
(pesticides, PCBs, PAHs and others) in samples of fresh water from the watercourse mouth and
seawater from the deployed sites, as well as the bioaccumulation of organochlorinated compounds and
PAHs in the transplanted animals.
Biomarker responses showed marked differences between reference and affected sites after 7 and 22
days. However it was only after 22 days that Principal Component Analysis (PCA) of the biomarker
responses distinguished between clams deployed in sites affected by the dispersion of the effluent of
the watercourse and those from the reference sites. The chemical analysis of water showed high
concentrations of pesticides close to El Albujón watercourse mouth, with the greatest input flux
corresponding to the organophosphate chlorpyrifos, followed by pendimethalin and naphthalene, and
at lower levels acenaphthene, terbuthylazine-desethyl and chlorpyrifos-methyl. In this regard, PCA
analysis showed that the biological effects of the mixture of pesticides in caged clams after 22 days
were reduced levels of AchE and SFG and increased levels of GR and phase II GST activity. An
Integrated Biomarker Response index was calculated from the combination of these biomarkers,
proving useful for the assessment of the impact of agricultural pollution in caged clams.Preprint3,761
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