871 research outputs found
Catálogo de los micromamíferos (Rodentia, Eulipotyphla, Chiroptera) del Cuaternario Superior Ibérico del Museu de Geologia de Barcelona, Spain
The present catalogue represents an attempt to list Middle–Upper Pleistocene and Holocene micromammal material deposited in the Museu de Geologia de Barcelona, coming from 12 Iberian Peninsula localities (ten from Catalonia, one from Castilla y León and one from Andalucia). It permits to observe changes in species geographical distribution as Iberomys cabrerae, Microtus oeconomus, Hystrix cristata or Citellus sp. with regard to their present location. By this way, we can observe the existence during the Middle–Upper Pleistocene of some today extinct species such as Pliomys lenki or Allocricetus bursae.
Key words: Middle-Upper Pleistocene, Holocene, Micromammals, Palaeobiogeography, Museo de Geologia de Barcelona, Spain.En este trabajo se presenta una lista del material de micromamíferos del Pleistoceno Medio-Superior y Holoceno depositado en el Museo de Geología de Barcelona, perteneciente a 12 yacimientos de la Península Ibérica (diez de Cataluña, uno de Castilla y León y uno de Andalucía). Este listado nos permite observar cambios en la distribución de especies como Iberomys cabrerae, Microtus oeconomus, Hystrix cristata o Citellus sp. respecto a su actual situación geográfica. Así mismo, nos permite vislumbrar la existencia durante el Pleistoceno Medio–Superior de algunas especies actualmente extintas, como Pliomys lenki y Allocricetus bursae.
Palabras clave: Pleistoceno Medio-Superior, Holoceno, Micromamíferos, Paleobiogeografía, Museu de Geologia de Barcelona, España
Loss of Melanopsin-Expressing Ganglion Cell Subtypes and Dendritic Degeneration in the Aging Human Retina
In mammals, melanopsin-expressing retinal ganglion cells (mRGCs) are, among other things, involved in several non-image-forming visual functions, including light entrainment of circadian rhythms. Considering the profound impact of aging on visual function and ophthalmic diseases, here we evaluate changes in mRGCs throughout the life span in humans. In 24 post-mortem retinas from anonymous human donors aged 10–81 years, we assessed the distribution, number and morphology of mRGCs by immunostaining vertical retinal sections and whole-mount retinas with antibodies against melanopsin. Human retinas showed melanopsin immunoreactivity in the cell body, axon and dendrites of a subset of ganglion cells at all ages tested. Nearly half of the mRGCs (51%) were located within the ganglion cell layer (GCL), and stratified in the outer (M1, 12%) or inner (M2, 16%) margin of the inner plexiform layer (IPL) or in both plexuses (M3, 23%). M1 and M2 cells conformed fairly irregular mosaics, while M3 cell distribution was slightly more regular. The rest of the mRGCs were more regularly arranged in the inner nuclear layer (INL) and stratified in the outer margin of the IPL (M1d, 49%). The quantity of each cell type decrease after age 70, when the total number of mRGCs was 31% lower than in donors aged 30–50 years. Moreover, in retinas with an age greater than 50 years, mRGCs evidenced a decrease in the dendritic area that was both progressive and age-dependent, as well as fewer branch points and terminal neurite tips per cell and a smaller Sholl area. After 70 years of age, the distribution profile of the mRGCs was closer to a random pattern than was observed in younger retinas. We conclude that advanced age is associated with a loss in density and dendritic arborization of the mRGCs in human retinas, possibly accounting for the more frequent occurrence of circadian rhythm disorders in elderly persons.This research was supported by grants from the Spanish Ministry of Economy and Competitiveness (MINECO-FEDER BFU2015-67139-R), Instituto de Salud Carlos III (RETICS-FEDER RD16/0008/0016) and Generalitat Valenciana (PROMETEO/2016/158)
Electric field control of exchange bias in multiferroic epitaxial heterostructures
The magnetic exchange bias between epitaxial thin films of the multiferroic
(antiferromagnetic and ferroelectric) hexagonal YMnO3 oxide and a soft
ferromagnetic (FM) layer is used to couple the magnetic response of the
ferromagnetic layer to the magnetic state of the antiferromagnetic one. We will
show that biasing the ferroelectric YMnO3 layer by an appropriate electric
field allows modifying and controlling the magnetic exchange bias and
subsequently the magnetotransport properties of the FM layer. This finding may
contribute to pave the way towards a new generation of electric-field
controlled spintronics devices.Comment: 15 pages, 5 figures, submitte
Electric field effects on magnetotransport properties of multiferroic Py/YMnO3/Pt heterostructures
We report on the exchange bias between antiferromagnetic and ferroelectric
hexagonal YMnO3 epitaxial thin films sandwiched between a metallic electrode
(Pt) and a soft ferromagnetic layer (Py). Anisotropic magnetoresistance
measurements are performed to monitor the presence of an exchange bias field.
When the heteroestructure is biased by an electric field, it turns out that the
exchange bias field is suppressed. We discuss the dependence of the observed
effect on the amplitude and polarity of the electric field. Particular
attention is devoted to the role of current leakage across the ferroelectric
layer.Comment: Accepted for publication in Philosophical Magazine Letters (Special
issue on multiferroics
Strain-driven non-collinear magnetic ordering in orthorhombic epitaxial YMnO3 thin films
We show that using epitaxial strain and chemical pressure in orthorhombic
YMnO3 and Co-substituted (YMn0.95Co0.05O3) thin films, a ferromagnetic response
can be gradually introduced and tuned. These results, together with the
measured anisotropy of the magnetic response, indicate that the unexpected
observation of ferromagnetism in orthorhombic o-RMnO3 (R= Y, Ho, Tb, etc) films
originates from strain-driven breaking of the fully compensated magnetic
ordering by pushing magnetic moments away from the antiferromagnetic [010]
axis. We show that the resulting canting angle and the subsequent ferromagnetic
response, gradually increase (up to ~ 1.2\degree) by compression of the unit
cell. We will discuss the relevance of these findings, in connection to the
magnetoelectric response of orthorhombic manganites.Comment: Text + Figs Accepted in J. Appl. Phy
Use of Nanomaterials in the Stabilization of Expansive Soils into a Road Real-Scale Application
Stabilization is a traditional strategy used to improve soils with the main objective of
ensuring that this base is compliant with the technical specifications required for the subsequent
development of different infrastructures. This study proposes the use of commercial nanomaterials,
based on a solution of silicates, to improve the technical characteristics and bearing capacity of the
expansive soil. A physical–chemical property study was carried out on the additive nanomaterial.
Subsequently, different mixtures of expansive soil, selected soil and artificial gravel with quicklime
and commercial nanomaterials were developed to evaluate the improvement obtained by the use of
nanomaterials in the technical characteristics of the soil. Compressive strength and the Californian
Bearing Ratio index were considerably increased. A full-scale study was carried out in which the
nanomaterial product was applied to two different sections of stabilized road compared to a control
section. The results obtained showed that the use of nanomaterial led to the possibility of reducing the
control section by 30 cm, thus achieving less use of quicklime and a mechanical means for preparing
the road section. The use of commercial nanomaterial improved the behavior of the stabilized
sub-base layer. Through life cycle assessment, this study has shown that the use of nanomaterials
reduces the environmental impact associated with soil stabilization.FEDER/Ministerio de Ciencia, Innovacion y Universidades-Agencia Estatal de Investigacion/Ecaryse
RCT-2017-6202-
Tracing the retina to analyze the integrity and phagocytic capacity of the retinal pigment epithelium
We have developed a new technique to study the integrity, morphology and functionality of the retinal neurons and the retinal pigment epithelium (RPE). Young and old control albino (Sprague-Dawley) and pigmented (Piebald Virol Glaxo) rats, and dystrophic albino (P23H-1) and pigmented (Royal College of Surgeons) rats received a single intravitreal injection of 3% Fluorogold (FG) and their retinas were analyzed from 5 minutes to 30 days later. Retinas were imaged in vivo with SD-OCT and ex vivo in flat-mounts and in cross-sections. Fifteen minutes and 24 hours after intravitreal administration of FG retinal neurons and the RPE, but no glial cells, were labeled with FG-filled vesicles. The tracer reached the RPE 15 minutes after FG administration, and this labeling remained up to 30 days. Tracing for 15 minutes or 24 hours did not cause oxidative stress. Intraretinal tracing delineated the pathological retinal remodelling occurring in the dystrophic strains. The RPE of the P23H-1 strain was highly altered in aged animals, while the RPE of the RCS strain, which is unable to phagocytose, did not accumulate the tracer even at young ages when the retinal neural circuit is still preserved. In both dystrophic strains, the RPE cells were pleomorphic and polymegathic
Empirical Installation of Linear Algebra Shared-Memory Subroutines for Auto-Tuning
The final publication is available at Springer via http://dx.doi.org/10.1007/s10766-013-0249-6The introduction of auto-tuning techniques in linear algebra shared-memory routines is analyzed. Information obtained in the installation of the routines is used at running time to take some decisions to reduce the total execution time. The study is carried out with routines at different levels (matrix multiplication, LU and Cholesky factorizations and linear systems symmetric or general routines) and with calls to routines in the LAPACK and PLASMA libraries with multithread implementations. Medium NUMA and large cc-NUMA systems are used in the experiments. This variety of routines, libraries and systems allows us to obtain general conclusions about the methodology to use for linear algebra shared-memory routines auto-tuning. Satisfactory execution times are obtained with the proposed methodology.Partially supported by Fundacion Seneca, Consejeria de Educacion de la Region de Murcia, 08763/PI/08, PROMETEO/2009/013 from Generalitat Valenciana, the Spanish Ministry of Education and Science through TIN2012-38341-C04-03, and the High-Performance Computing Network on Parallel Heterogeneus Architectures (CAPAP-H). The authors gratefully acknowledge the computer resources and assistance provided by the Supercomputing Centre of the Scientific Park Foundation of Murcia and by the Centre de Supercomputacio de Catalunya.Cámara, J.; Cuenca, J.; Giménez, D.; García, LP.; Vidal Maciá, AM. (2014). Empirical Installation of Linear Algebra Shared-Memory Subroutines for Auto-Tuning. 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Recensiones [Revista de Historia Económica Año XII Primavera-Verano 1994 n. 2 pp. 437-472]
Editada en la Universidad Carlos IIIRobert C. Allen. Enclosure and the Yeoman. The Agricultural Development of the SouthMidlands 1410-1850 (Por Gaspar Feliú).-- Ruggiero Romano. Conjonctures opposées. La «crise» du XVII siècle: en Europe et en Amérique ibérique (Por Gaspar Feliú).-- Simposio de Historia de las Mentalidades. Instituto Nacional de Antropología e Historia, México. Familia y poder en Nueva España (Por Juan Carlos Sola Corbacho).-- Leandro Prados de la Escosura y Samuel Amaral (Eds.). La independencia americana: consecuencias económicas (Por Javier Cuenca).-- M.ª Cruz Romeo Mateo. Entre el orden y la revolución. La formación de la burguesía liberal en la crisis de la monarquía absoluta (1814-1833) (Por Ricardo Robledo).-- José G. Cayuela Fernández. Bahía de ultramar. España y Cuba en el siglo XIX. El control de las relaciones coloniales (Por Candelaria Sáiz Pastor).-- José Manuel Pose Antelo. La economía y la sociedad compostelanas a finales del siglo XIX (Por Carlos Larrinaga Rodríguez).-- Frank Broeze. Mr Brooks and the Australian Trade. Imperial Business in the Nineteenth Century (Por Jesús M.ª Valdaliso).-- Robert H. Bremner. Desde lo más bajo. El descubrimiento de la pobreza en Estados Unidos / James T. Patterson. La lucha contra la pobreza en los Estados Unidos de América, 1900-1985 (Por Nuria Puig).-- Justo Navarro Clari. Curso de Historia Económica (Por Antonio Santamaría)Publicad
Association of objectively measured physical activity with body components in European adolescents
Background: Physical activity (PA) is suggested to contribute to fat loss not only through increasing energy expenditure “per se” but also increasing muscle mass; therefore, it would be interesting to better understand the specific associations of PA with the different body’s components such as fat mass and muscle mass. The aim of the present study was to examine the association between objectively measured PA and indices of fat mass and muscle components independently of each other giving, at the same time, gender-specific information in a wide cohort of European adolescents.
Methods: A cross-sectional study in a school setting was conducted in 2200 (1016 males) adolescents (14.7 ±1.2 years). Weight, height, skinfold thickness, bioimpedance and PA (accelerometry) were measured. Indices of fat mass (body mass index, % fat mass, sum of skinfolds) and muscular component (assessed as fat-free mass) were calculated. Multiple regression analyses were performed adjusting for several confounders including fat-free mass and fat mass when possible.
Results: Vigorous PA was positively associated with height (p?<?0.05) in males, whilst, vigorous PA, moderate-vigorous PA and average PA were negatively associated with all the indices of fat mass (all p?<?0.01) in both genders, except for average PA in relation with body mass index in females. Regarding muscular components, vigorous PA showed positive associations with fat-free mass and muscle mass (all p?<?0.05) in both genders. Average PA was positively associated with fat-free mass (both p?<?0.05) in males and females.
Conclusion: The present study suggests that PA, especially vigorous PA, is negatively associated with indices of fat mass and positively associated with markers of muscle mass, after adjusting for several confounders (including indices of fat mass and muscle mass when possible). Future studies should focus not only on the classical relationship between PA and fat mass, but also on PA and muscular components, analyzing the independent role of both with the different PA intensities
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