2,137 research outputs found
The formation of planetary disks and winds: an ultraviolet view
Planetary systems are angular momentum reservoirs generated during star
formation. This accretion process produces very powerful engines able to drive
the optical jets and the molecular outflows. A fraction of the engine energy is
released into heating thus the temperature of the engine ranges from the 3000K
of the inner disk material to the 10MK in the areas where magnetic reconnection
occurs. There are important unsolved problems concerning the nature of the
engine, its evolution and the impact of the engine in the chemical evolution of
the inner disk. Of special relevance is the understanding of the shear layer
between the stellar photosphere and the disk; this layer controls a significant
fraction of the magnetic field building up and the subsequent dissipative
processes ougth to be studied in the UV.
This contribution focus on describing the connections between 1 Myr old suns
and the Sun and the requirements for new UV instrumentation to address their
evolution during this period. Two types of observations are shown to be needed:
monitoring programmes and high resolution imaging down to, at least,
milliarsecond scales.Comment: Accepted for publication in Astrophysics and Space Science 9 figure
Interaction of the chromium–iron black pigment with porcelanised stoneware
A study has been undertaken on the interaction between the (Fe,Cr)2O3 black pigment and an industrial porcelanised stoneware composition at its firing temperature. The results indicate that the glassy phase that forms during firing preferentially extracts Fe2O3 from the pigment and probably contributes some Al2O3 to it, enriching the pigment composition in Cr2O3, without changing pigment crystal structure. The pigment alteration process mainly affects porcelanised stoneware microstructure and, to a lesser extent, color
Modeling Surface Energy Fluxes over a Dehesa (Oak Savanna) Ecosystem Using a Thermal Based Two-Source Energy Balance Model (TSEB) I
Savannas are among the most variable, complex and extensive biomes on Earth, supporting
livestock and rural livelihoods. These water-limited ecosystems are highly sensitive to changes in
both climatic conditions, and land-use/management practices. The integration of Earth Observation
(EO) data into process-based land models enables monitoring ecosystems status, improving its
management and conservation. In this paper, the use of the Two-Source Energy Balance (TSEB)
model for estimating surface energy fluxes is evaluated over a Mediterranean oak savanna (dehesa).
A detailed analysis of TSEB formulation is conducted, evaluating how the vegetation architecture
(multiple layers) affects the roughness parameters and wind profile, as well as the reliability of EO
data to estimate the ecosystem parameters. The results suggest that the assumption of a constant
oak leaf area index is acceptable for the purposes of the study and the use of spectral information
to derive vegetation indices is sufficiently accurate, although green fraction index may not reflect
phenological conditions during the dry period. Although the hypothesis for a separate wind speed
extinction coefficient for each layer is partially addressed, the results show that taking a single oak
coefficient is more precise than using bulk system coefficient. The accuracy of energy flux estimations,
with an adjusted Priestley–Taylor coefficient (0.9) reflecting the conservative water-use tendencies
of this semiarid vegetation and a roughness length formulation which integrates tree structure and
the low fractional cover, is considered adequate for monitoring the ecosystem water use (RMSD
~40W m-2)
Evidence for stellar driven outflows from the Classical T Tauri star RY Tau
RY Tau is a rapidly rotating Classical T Tauri star observed close to
edge-on. The combination of new HST/STIS observations obtained in 2001 with
HST/GHRS Archive data from 1993 has allowed us to get, for the first time,
information on the thermal structure and the velocity law of the wind. The
repeated observations of the Si III] and C III] lines show a lack of changes
with time in the blue side of the profile(dominated by the wind contribution).
Very high temperature plasma (log Te = 4.8) is detected at densities of 9.5<log
ne(cm3)< 10.2 associated with the wind. The emitting volumes are about
(0.35Ro)^3 suggesting a stellar origin. The wind kinematics derived from the
profiles (Si III], C III] and [O II]) does not satisfy the theoretical
predictions of MHD centrifugally driven disk winds. The profiles' asymmetry,
large velocity dispersions and small variability as well as the small emitting
volumes are best explained if the wind is produced by the contribution of
several outflows from atmospheric open field structures as those observed in
the Sun.Comment: 11pages, 3 figure
MicroRNA as crucial regulators of gene expression in estradiol-treated human endothelial cells.
Background/Aims: Estrogen signalling plays an important role in vascular biology as it modulates vasoactive and metabolic pathways in endothelial cells. Growing evidence has also established microRNA (miRNA) as key regulators of endothelial function. Nonetheless, the role of estrogen regulation on miRNA profile in endothelial cells is poorly understood. In this study, we aimed to determine how estrogen modulates miRNA profile in human endothelial cells and to explore the role of the different estrogen receptors (ERα, ERβ and GPER) in the regulation of miRNA expression by estrogen. Methods: We used miRNA microarrays to determine global miRNA expression in human umbilical vein endothelial cells (HUVEC) exposed to a physiological concentration of estradiol (E2; 1 nmol/L) for 24 hours. miRNA-gene interactions were computationally predicted using Ingenuity Pathway Analysis and changes in miRNA levels were validated by qRT-PCR. Role of ER in the E2-induced miRNA was additionally confirmed by using specific ER agonists and antagonists. Results: miRNA array revealed that expression of 114 miRNA were significantly modified after E2 exposition. Further biological pathway analysis revealed cell death and survival, lipid metabolism, reproductive system function, as the top functions regulated by E2. We validated changes in the most significantly increased (miR-30b-5p, miR-487a-5p, miR-4710, miR-501-3p) and decreased (miR-378h and miR-1244) miRNA and the role of ER in these E2-induced miRNA was determined. Results showed that both classical, ERα and ERβ, and membrane-bound ER, GPER, differentially regulated specific miRNA. In silico analysis of validated miRNA promoters identified specific ER binding sites. Conclusion: Our findings identify differentially expressed miRNA pathways linked to E2 in human endothelial cells through ER, and provide new insights by which estrogen can modulate endothelial function
Estudio de cerámicas de la Edad del Bronce en yacimientos arqueológicos de la provincia de Guadalajara
En este trabajo se presenta el resultado del estudio de fragmentos cerámicos del período Eneolítico,\ud
aplicando diferentes métodos analíticos (difracción de rayos X, análisis térmico, estudio petrográfico, etc.).\ud
Las muestras cerámicas pertenecen a una serie de refugios de dicho período (2800-2200 años a. de c.,\ud
situados en la provincia de Guadalajara, refugios de Peña Corva, Cueva Harzal, y Enebrales), recogidos\ud
y estudiados por Valiente Malla y otros autores.\ud
El interés de este estudio arqueométrico es el de establecer a través de la composición y característica\ud
de los fragmentos cerámicos, el origen, temperatura y atmósfera de cocción y posible parecido entre\ud
ellas, que establezcan conexiones entre los refugios.This paper presents the results of research on paste composition and firing of ancient ceramics\ud
by applications of different analytical methods (XRD, petrographie microscope, ATG,...).\ud
The samples of ceramics come from the shelters of Peña Corva in Santamera, Cueva Harzal\ud
in Olmedillas and Enebrales in Tamajón (Guadalajara, Spain)... collected by Valiente Malla, J.\ud
and other authors; and are according with the system stablished or the Eneolithic Period,\ud
2800-2200 years a.C. old, just as Delibes G.\ud
Though the archaeoceramic analysis we intend to konw: ceramics composition, process of\ud
firing and temperature, firing atmosphere, local origin, conections between the samples, and burial state activity the mineralogical change on it
Role of the interfacial water structure on electrocatalysis: Oxygen reduction on Pt(1 1 1) in methanesulfonic acid
Most of electrocatalytic reactions occur in an aqueous environment. Understanding the influence of water structure on reaction dynamics is fundamental in electrocatalysis. In this work, the role of liquid water structure on the oxygen reduction at Pt(1 1 1) electrode is analyzed in methanesulfonic (MTSA) and perchloric acids. This is because these different anions can exert a different influence on liquid water structure. Results reveal a lower ORR electrode activity in MTSA than in HClO4 solutions and they are discussed in light of anion's influence on water structural ordering. From them, the existence of an outer-sphere, rate determining, step in the ORR mechanism is suggested.This work has been carried out under MINECO project CTQ2013-44083-P (Spain). APSR acknowledges the scholarship “Estudiantes sobresalientes de posgrado” at the UNAL and COLCIENCIAS National Doctoral Scholarship (567). MFS acknowledges the support of UNAL (Research Project 19030)
Cómo minimizar los cambios radiológicos laterales en la osteotomía valguizante de adición medial de rodilla
Objetivo:
estudiar la relación entre posición del injerto en Osteotomía Valguizante de Adición
(OVA) en rodilla, los cambios radiológicos experimentados por la rótula y la pendiente tibial y su correlación
clínica.
Material y métodos:
estudio retrospectivo de 10 pacientes operados de OVA. Medimos el cambio experimentado tras la osteotomía en Índice de Catón y la pendiente tibial y su relación con la ubicación del injerto.
Valoración clínica mediante test de Lisholm y WOMAC.
Resultados:
edad media de 49.5 años, seguimiento medio de 32,2 meses. Se observa un cambio estadísticamente significativo de 1,45º en la pendiente tibial y de 0,15
unidades (Índice Catón) en la altura de la patela, pero sin correlación con la clínica. La ubicación del injerto en el
cuadrante posterior se halló en el 80% de los casos.
Conclusión
: la osteotomía valguizante de adición medial tiene
buenos resultados clínicos. Los cambios en la pendiente tibial y en la patela son menores cuanto más posterior es
la ubicación del injerto.Objectives:
we investigated changes in patellar height and tibial inclination angle after open-wedge high tibial osteotomy, the effect of these changes on patient satisfaction and the correlation with the graft
position.
Methods:
retrospective study of 10 knees who underwent open-wedge proximal tibial osteotomy with
allograft and medial plate for medial compartment. Were measured pre- and postoperatively tibial inclination angle, and patellar height (Caton Index), and we study the correlation of these changes with the location of the graft.
Clinical evaluations were made using the Lysholm and WOMAC score.
Results:
the mean age was 49.5 years, the
mean follow up was 32,2 months. The mean increase in the tibial inclination angle was 1,45 ° (p<0.05) and the
mean of decrease in patellar height was 0.15 Units Caton Index (p<0.05). There weren’t correlation between radiological changes and patients satisfaction. The graft localization was posterior in 80% of patients.
Conclusion:
the open-wedge tibial osteotomy has good results and high clinical satisfaction. Changes in the tibial slope and
the patellar height are lower if the graft position is posterior
Brief Results of a Trawl Experimental Survey at NW Atlantic
An experimental survey was carried out in NAFO Regulatory Area (Div. 6EFGH and 4XWVs) and adjacent
international Southern waters during last Quarter of year 2004, with one polyvalent Spanish trawler, using "Gloria"
pelagic gear and bottom gear, with the aim to obtain data on distribution and biology on pelagic and demersal
species in non-habitual grounds for the Spanish fleet. A scientific observer was on board to collect the information
on fishing activity (effort, depth, etc.) and biological data (length distributions, length-weight relationships, etc.). A
total of 119 hauls were carried out. Samplings were conducted in a wide geographical and bathymetrical range.
During the survey, Alfonsino (Beryx splendens) was the main caught species
Occupational therapy and professional identity: narratives of professionals through life history. study protocol
[Abstract] Project title: Occupational therapy and professional identity: narratives of professionals through life history. Study Protocol. Design: Qualitative research, using a socio-critical paradigm and biographical-narrative method where participants were selected through theoretical sampling and snowball sampling strategy. Data collection techniques were life stories, constructed through biograms, self-reports and biographical interviews. Abductive reasoning was used along with structural analysis techniques, narrative analysis, and ATLAS. ti software. Objective: To describe and analyze the occupational construct of the professional identity of occupational therapists in Spain. Specific Objectives: (1) Analyze life events, transitions, and turning points that contribute to the outlining of the life journey of professional identity. (2) Explore the management of professional tasks. (3) Analyze the nature of the knowledge required to carry out the role. (4) Examine in detail the strategies applied to the personal engagement of occupational therapists. Study Population and Total Number of Participants: The study population consisted of professionals who are currently working as occupational therapists in Spain. The number of participants was established when data saturation was reached, with a total of nine informants
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