Structural, electronic and spectroscopic effects of Ga codoping on Ce doped yttrium aluminum garnet: first principles study

Periodic-boundary-conditions density-functional theory and embedded cluster wave-function theory calculations performed on Ga-doped and Ce,Ga-codoped yttrium aluminum garnet (YAG) Y3 Al5 O12, allowed for the determination of the atomistic structures of these materials when Ga substitutes for Al in octahedral and tetrahedral sites and Ce substitutes for Y, as well as for the shifts of the local excited states of main character Ce4 f1, Ce5 d1, and Ce6 s1 induced by Ga codoping. The experimental blueshift experienced by the lowest Ce4f→5d absorption upon Ga codoping has been reproduced and it has been found to be caused by the reduction in the effective ligand splitting of the 5 d1 manifold, which is due to Ga forcing an anisotropic expansion of the surroundings of Ce. The effects of Ga on the energy centroids of the 4 f1 and 5 d1 configurations are negligible. The direct electronic effects of Ga are insignificant and all effects of Ga codoping are a consequence of the geometrical distortions it causes. This picture corresponds to a simple model under use and it contrasts with the case of La codoping, where the direct electronic effects of La and the centroid energy shift are responsible for the redshift. The reason for such a different behavior could lie in the distance between the dopant and the Ce impurity, which is shorter for Ce,La:YAG than for Ce,Ga:YAG

Fondos

Construcción de guitarras Durán Ferrer (2902009

Estudios de primeros principios en YAG (Y3Al5O12) dopado con Ce: codopaje, defectos y antisite y transiciones 4f-5d en Ce3+

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química. Fecha de lectura: 11/3/201

Atomistic and electronic structure of antisite defects in yttrium aluminum garnet: density functional study

First-principles density-functional theory calculations have been performed on the atomistic structure, electronic structure, and distribution of antisite defects (AD) in yttrium aluminum garnet (YAG) Y3 Al5 O12. The formations of one and two antisite defects per unit cell are endothermic and the formation energy per defect is lower in 2AD than in 1AD. In the most stable 1AD structure, Y and Al are as close as possible and two oxygen atoms become unbound to Al rising the energy of their (highest) valence levels and introducing a defect level in the gap 0.25 eV above the top of the perfect YAG valence band. The binding energy between the individual substitutional defects YAl and AlY to form 1AD is 0.74 eV. The most stable 2AD structure is made of two single ADs linked together with one AlO6 moiety and it has basically the same electronic structure as the most stable 1AD; it is the only 2AD structure that preserves the inversion center with respect to the unit-cell center. In this case, the binding energy between two single ADs is 0.22 eV

Antisite defects in Ce-doped YAG (Y3Al5O12): First-principles study on structures and 4f-5d transitions

This is an electronic version of an article published in Journal of Materials Chemistry. Muñoz García, A.B., Barandiarán, Z. and Luis Seijo. "Antisite defects in Ce-doped YAG (Y3Al5O12): First-principles study on structures and 4f-5d transitions". Journal of Materials Chemistry 22 (2012): 19888-1989

Structural effects and 4f-5d transition shifts induced by La-codoping in Ce-doped yttrium aluminium garnet: first principles study

This work was partly supported by a grant from Ministerio de Ciencia e Innovacion, Spain (Direccion General de Programas y Transferencia de Conocimiento MAT2008-05379/MAT). A.B.M.-G. acknowledges a contract of the program Personal Investigador en Formacio

Python software tools for GNSS interferometric reflectometry (GNSS-IR)

[EN] Global Navigation Satellite System (GNSS) interferometric reflectometry, also known as the GNSS-IR, uses data from geodetic-quality GNSS antennas to extract information about the environment surrounding the antenna. Soil moisture moni-toring is one of the most important applications of the GNSS-IR technique. This manuscript presents the main ideas and implementation decisions needed to write the Python code for software tools that transform RINEX format observation and navigation files into an appropriate format for GNSS-IR (which includes the SNR observations and the azimuth and elevation of the satellites) and to determine the reflection height and the adjusted phase and amplitude values of the interferometric wave for each individual satellite track. The main goal of the manuscript is to share the software with the scientific com-munity to introduce new users to the GNSS-IR technique.The authors want to thank the staff of the Cajamar Center of Experiences, and especially Carlos Baixauli, for their support and collaboration in the Paiporta experiment. The authors also want to thank Alfred Leick and Steve Hilla for their valuable comments and suggestions.Martín Furones, ÁE.; Luján García Muñoz, R.; Anquela Julián, AB. (2020). Python software tools for GNSS interferometric reflectometry (GNSS-IR). GPS Solutions. 24(4):1-7. https://doi.org/10.1007/s10291-020-01010-0S17244Chen Q, Won D, Akos DM, Small EE (2016) Vegetation using GPS interferometric reflectometry: experimental results with a horizontal polarized antenna. IEEE J Select Top Appl Earth Obs Rem Sens 9(10):4771–4780. https://doi.org/10.1109/JSTARS.2016.2565687Chew CC, Small EE, Larson KM, Zavorotny VU (2014) Effects of near-surface soil moisture on GPS SNR data: development and retrieval algorithm for soil moisture. IEEE T Geosci Rem Sens 52(1):537–543. https://doi.org/10.1109/TGRS.2013.2242332Chew CC, Small EE, Larson KM, Zavorotny UZ (2015) Vegetation sensing using GPS-interferometric reflectometry: theoretical effects of canopy parameters on signal-to-noise ratio data. IEEE T Geosci Rem Sens 53(5):2755–2764. https://doi.org/10.1109/TGRS.2014.2364513Chew CC, Small EE, Larson KM (2016) An algorithm for soil moisture estimation using GPS-interferometric reflectometry for bare and vegetated soil. GPS Solut 20(3):525–537. https://doi.org/10.1007/s10291-015-0462-4Gurtner W, Estey L (2015) RINEX: the receiver independent exchange format version 3.03. ftp://igs.org/pub/data/format/rinex303.pdfLarson KM, Small EE, Gutmann ED, Bilich AL, Axelrad A, Braun JJ (2008a) Using GPS multipath to measure soil moisture fluctuations: initial results. GPS Solut 12(3):173–177. https://doi.org/10.1007/s10291-007-0076-6Larson KM, Small EE, Gutmann ED, Bilich AL, Braun JJ, Zavorotny VU (2008b) Use of GPS receivers as a soil moisture network for water cycle studies. Geophys Res Lett 35:L24405. https://doi.org/10.1029/2008GL036013Larson KM, Gutmann E, Zavorotny VU, Braun J, Williams M, Nievinski FG (2009) Can we measure snow depth with GPS receivers? Geophys Res Lett 36:L17502. https://doi.org/10.1029/2009GL039430Larson KM, Braun JJ, Small EE, Zavorotny VU (2010) GPS multipath and its relation to near-surface soil moisture content. IEEE J Selec Top Appl Earth Obs Rem Sens 3(1):91–99. https://doi.org/10.1109/JSTARS.2009.2033612Larson KM, Nievinski FG (2013) GPS snow sensing: results from the EarthScope plate boundary observatory. GPS Solut 17(1):41–52. https://doi.org/10.1007/s10291-012-0259-7Leick A, Rapoport L, Tatarnikov D (2015) GPS satellite surveying, 4th edn. Wiley, Hoboken, p 840Martín A, Ibañez S, Baixauli C, Blanc S, Anquela AB (2020) Multi-constellation interferometric reflectometry with mass-market sensors as a solution for soil moisture monitoring. Hydrol Earth Syst Sci. https://doi.org/10.5194/hess-24-3573-2020Nievinski GG, Larson KM (2014) An open source GPS multipath simulator in Matlab/Octave. GPS Solut 18:473–481. https://doi.org/10.1007/s10291-014-0370-zNischan T (2016) GFZRNX—RINEX GNSS data conversion and manipulation toolbox (Version 1.05). GFZ Data Serv. https://doi.org/10.5880/GFZ.1.1.2016.002Roesler C, Larson KM (2018) Software tools for GNSS interferometric reflectometry (GNSS-IR). GPS Solut. https://doi.org/10.1007/s10291-018-0744-8Roussel N, Ramilien G, Frappart F, Darrozes J, Gay A, Biancale R, Striebig N, Hanquiez V, Bertin X, Allain A (2015) Sea level monitoring and sea estimate using a single geodetic receiver. Remote Sens Environ 171:261–277. https://doi.org/10.1016/j.rse.2015.10.011Roussel N, Frappart F, Ramillien G, Darroes J, Baup F, Lestarquit L, Ha MC (2016) Detection of soil moisture variations using GPS and GLONASS SNR data for elevation angles ranging from 2º to 70º. IEEE J Selec Top Appl Earth Obs Rem Sens 9(10):4781–4794. https://doi.org/10.1109/JSTARS.2016.2537847Sanz J, Juan JM, Hernández-Pajares M (2013) GNSS data processing. Volume I: fundamentals and algorithms. European Space Agency Communications, 223 ppSmall EE, Larson KM, Chew CC, Dong J, Ochsner TE (2016) Validation of GPS-IR soil moisture retrievals: comparison of different algorithms to remove vegetation effects. IEEE J Selec Top Appl Earth Obs Rem Sens 9(10):4759–4770. https://doi.org/10.1109/JSTARS.2015.2504527Vey S, Güntner A, Wickert J, Blume T, Ramatschi M (2016) Long-term soil moisture dynamics derived from GNSS interferometric reflectometry: a case study for Sutherland, South Africa. GPS Solut 20:641–654. https://doi.org/10.1007/s10291-015-0474-0Wan W, Larson KM, Small EE, Chew CC, Braun JJ (2015) Using geodetic GPS receivers to measure vegetation water content. GPS Solut 19:237–248. https://doi.org/10.1007/s10291-014-0383-7Zhang S, Roussel N, Boniface K, Ha MC, Frappart F, Darrozes J, Baup F, Calvet JC (2017) Use of reflected GNSS SNR data to retrieve either soil moisture or vegetation height from a wheat crop. Hydrol Earth Syst Sci 21:4767–4784. https://doi.org/10.5194/hess-21-4767-201

Estudio de la percepción que el profesorado en activo posee sobre el maltrato entre iguales

El maltrato entre escolares es un tema de actualidad con una importancia creciente debido al aumento de casos y a la gravedad de los mismos. Por esta razón es necesario estudiar el fenómeno con detenimiento desde la perspectiva de todos los implicados. Este artículo estudia la percepción y conocimiento que 95 profesores/as en activo poseen del maltrato entre iguales, del mismo modo, se analiza la relación con la experiencia docente y el ciclo educativo al que pertenecen. En la recogida de los datos se utiliza el “Cuestionario sobre el Maltrato entre Iguales en la Escuela”, traducido y adaptado de Nicolaides, Toda y Smith (2002). Los resultados muestran similitudes con otros estudios, y reflejan datos interesantes para una mejora de la formación del profesorado. En la relación con el ciclo educativo y la experiencia docente, debe destacarse que el conocimiento de los docentes suelen estar ligado a las características del maltrato en el ciclo educativo al que pertenecen, y que la escasa experiencia se relaciona con una sobreestimación del grado de incidencia del fenómeno

Understanding the role of food matrix on the digestibility of dairy products under elderly gastrointestinal conditions

[EN] This study aimed to evaluate the effect of some elderly in vitro gastrointestinal (GI) conditions on proteolysis and lipolysis extent, calcium, vitamins A and D bioaccessibility and lactose release in milk, yogurt, fresh and aged cheeses. To evaluate the impact of the some oral, gastric and intestinal disorders appearing with ageing on dairy digestion, three in-vitro elderly models were applied (E1 (oral altered conditions), E2 (oral and gastric altered conditions) and E3 (oral, gastric and intestinal altered conditions)) plus a healthy adult one as control. Proteolysis extent was significantly affected by elderly GI alterations (p < 0.05) (around 40% of reduction compared to control), being fresh and aged cheese proteolysis the most affected with an important descrease in leucine release (18 and 25%, respectively). Calcium, vitamins A and D3 bioaccesibility and lactose release seemed not to be highly compromised in these models of elderly conditions; however, the micronutrients bioaccessibility was very dependent on dairy matrix¿s structure. Finally, the amount of the lipid hydrolyzed fraction of cheeses is not influenced in the investigated models.The authors gratefully acknowledge the financial support from the Generalitat Valenciana AICO/2018/289. Ever Hernández-Olivas is recipient of a pre-doctoral grant from the Mexican Government through the CONACYT (MEX/Ref. 306682) and Janaina Sanchez-García of a master s degree scholarship funded by the Ecuadorian Government through the SENESCYT (contract CZ05-000716-2018)Hernández-Olivas, E.; Muñoz-Pina, S.; Sánchez-García, J.; Andrés Grau, AM.; Heredia Gutiérrez, AB. (2020). Understanding the role of food matrix on the digestibility of dairy products under elderly gastrointestinal conditions. Food Research International. 137:1-10. https://doi.org/10.1016/j.foodres.2020.109454S11013

Ultrasound pretreatment to enhance the enzymatic hydrolysis of Dictyota dichotoma for sugars production

There is an increasing demand for natural resources for biorefining purposes. In this regard, the efficient use of seaweed seems promising as they represent a sustainable feedstock with advantageous characteristics, given their abundant concentration of carbohydrates and low lignin levels. However, in the context of sugar platform biorefineries, to make this activity sustainable, high availability of seaweed biomass is required. In this respect, beach-cast seaweed biomass represents an attractive alternative, reducing the negative impact associated with its accumulation and decomposition on the beaches, which affects the financial income of the region. In this study, Dictyota dichotoma deposited on the coasts of Cadiz (Spain) was collected at the end of the autumn season and used as raw material for the production of simple sugars in the frame of a biorefinery approach. The potential of ultrasound pretreatment was applied to two biomass concentrations (2.1 and 4.3 % w/v), at different amplitude percentages (20, 40 and 60 %) and pretreatment times (15, 40 and 60 min) to enhance algal biomass saccharification. The best condition for reducing sugars (RS) production was: 4.3 % w/v of algal suspension and 40 min pretreatment at 40 % amplitude. This condition supposes specific energy (Es) of 6.78 MJ/kg and leads to a total sugar concentration of 163.64 ± 0.93 mg RS/g dried biomass. A slight improvement in RS production could be attained by increasing the amplitude to 60 % (165.52 ± 3.89 mg/g) but requiring 50 % higher specific energy. Experimental data were fitted to simple first-order kinetics. The hydrolysis rate constant k was a function of the biomass concentration and practically independent of the energy applied. In addition, the average value of k was 8.6 times higher than that for non-pretreated seawee