355 research outputs found
Useful Life of Prescribed Fires in a Southern Mediterranean Basin: An Application to Pinus pinaster Stands in the Sierra Morena Range
Prescribed fire is a globally relevant fuel treatment for surface fuel management and wildfire hazard reduction. However, Mediterranean ecosystems are adapted to low and moderate fires; hence, the useful life of prescribed fires is limited. Useful life is defined as the effective rotation length of prescribed fires to mitigate fire spread based on critical surface intensity for crown combustion. In this sense, the useful life of a prescribed fire focuses on surface fuel dynamics and its potential fire behavior. In Pinus pinaster stands, the useful life can be established between 0 and 4 years. Canopy base height, time elapsed from the burning, postfire precipitation, and fine fuel moisture content during the burning were identified as the most important variables in postburn fuel dynamics. Other stand characteristics and postfire precipitation can improve the fine fuel and live fuel dynamics models. Our findings support prescribed fires as an effective fuel treatment in the medium term for forest fire prevention, according to stand characteristics and burning implementation conditions. In this sense, forest managers can use the proposed decision tree to identify the useful life of each prescribed fire based on fine fuel moisture content during burning implementation
Sistema de gestión de programas de educación ambiental, una aplicación para el desarrollo comunitario
El Sistema para la Gestión de Programas de Educación Ambiental (SGPA), trata de una aplicación WEB que permite gestionar diversos programas de Educación Ambiental con el objeto de fomentar la prevención y cuidado del Medio Ambiente, a los estudiantes del Instituto Tecnológico de Acapulco que realizaran el Servicio Social como requisito para cubrir su programa curricular; y posteriormente con los alumnos de Nivel Medio Superior pertenecientes al mismo sistema tecnológico.
Con esta aplicación se pretende que los alumnos que cumplan el requisito para realizar su servicio social, se registren en esta herramienta y propongan algún programa o actividad relacionada con acciones que fomenten a la sociedad el cuidado del Medio Ambiente.
Los alumnos registrados con alguno de los programas de educación ambiental, serán evaluados por los responsables de la Oficina de Servicio Social y Sistema de Gestión Ambiental quienes validaran a través de la aplicación, el cumplimiento de los requisitos para la aceptación; facilitando también los trámites, gestión y seguimiento de los procedimientos administrativos que se realizan en la institución. Con estos programas de capacitación, los alumnos adquieren una formación integral, promueven la cultura a través de la educación ambiental y por ende el desarrollo sustentable de las comunidades en la región. Con la gestión de los programas de educación ambiental a través de la aplicación SGPA, se contribuirá con el mejoramiento de calidad de vida de las personas generando impactos de desarrollo sustentable positivos para la región
Employee Innovation Using Ideation Contests. Seven-step process to align strategic challenges with the innovation process
This is an Accepted Manuscript version of the following article, accepted for publication in Research-Technology Management. Research-Technology Management 63.5 (2020): 20 – 28. It is deposited under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any wayResearchers and practitioners have shown great interest in crowdsourcing for problem solving. Although scholars have developed several conceptual frameworks that outline the fundamentals of crowdsourcing, few studies provide a detailed process to successfully implement it. Our results from a multiple case study comprising four major Spanish organizations that have implemented ideation contests—Madrid City Hall, Sabadell Bank, Endesa, and Repsol Group—show how internal ideation contests can foster a culture of innovation in which employees can feel accomplished and receive recognition by presenting new ideas and innovative possibilities. We present a seven-step process that describes the key analytical and decision-making components required to lead the design and rollout of internal ideation contests for which the goals are to align strategic challenges with the innovation proces
Competencia digital, digitalización de la formación y MOOC para maestros/as de Geografía de Educación Primaria
La Sociedad de la Información y la Comunicación (SIC), junto a las actuales demandas de la formación universitaria, interconectada y globalizada, está modificando las estrategias y modelos de enseñanza y aprendizaje. El presente estudio evalúa las potencialidades educativas y pedagógicas, así como las dificultades y retos actuales de las estrategias de aprendizaje abierto MOOC (Massive Open Online Course). Para ello, se ha analizado el Curso 0: Didáctica de la Geografía a través de Google Earth, orientado a la formación inicial del profesorado de Educación Primaria, que se implementará en los Departamentos de Didáctica General y Específicas de las Universidades de Alicante y Burgos
Characterization of motivation and type of physical-sport practice in adults through COMPASS profiles
Physical Activity and Sport Practice (PASP) have grown in popularity in last years given its positive effects
at physiological, social, cognitive and emotional level. Several researches have studied the main motivations
involved in PASP using the Self-Determination Theory, highlighting the importance of intrinsic and extrinsic
reasons. This descriptive and cross sectional study aims to establish the main motivations involved in
physical activity and to identify its association with the sport profiles proposed by COMPASS project (2000).
The research was conducted with a sample of 1002 adults (a 53% is female and a 47% is male) from Sevilla
( = 45.35 years old; SD = 17.96), using the C-PAFYD questionnaire with a reliability of α = .84. The results
show that profile 1 (competitive and intensive) comprises intrinsic and extrinsic motivations such as
hedonism, desire of competition and to achieve a sport career, while profile 2 is oriented towards least self-determined motivations as health improving. In addition, these participants do physical activity alone or with
co-workers. The profiles 3 and 4 (regular and non-organized physical activity) are related to motivations of
social and ludic type. In fact, this sport practice is mainly done with friends and peers in public places. Finally,
profiles 5 and 6, which are associated with an irregular and occasional PASP, manifested extrinsic
motivations such as disease preventio
An ab initio analytical potential energy surface for the O(3P) + CS(X1Σ+) → CO(X1Σ+) + S(3P) reaction useful for kinetic and dynamical studies
The N(4Su) + NO(X 2Π) → N 2(X 1Σg+) + O( 3Pg) reaction plays an important role in the upper atmosphere chemistry and as a calibration system for discharge flow systems. Surprisingly, very little theoretical and experimental work has been devoted to the characterization of the dynamical features of this system. In this work a Sorbie-Murrell expression for the lowest 3A″ potential energy surface (PES) connecting reactants in their ground electronic states based upon the fitting of an accurate ab initio CI grid of points has been derived. The PES fitted shows no barrier to reaction with respect to the reactants asymptote in accordance with experimental findings and becomes highly repulsive as the NNO angle is varied away from the saddle point geometry. The results of preliminary quasiclassical trajectory calculations on this surface reproduce very well the experimental energy disposal in products, even though the vibrational distribution derived from trajectories seems to be a bit cooler than the experimental data. Moreover, thermal rate constants derived from trajectories are in excellent accordance with experimental value
An analytical representation of the ground potential energy surface (2A') of the H + Cl2 → HCl + Cl and Cl + HCl → HCl + Cl reactions, based on ab initio calculations
In this work we have studied at an ab initio level the lowest 2A′ potential energy surface (PES) of the HCl2 system. This PES is involved in the H(2S)+Cl2(X 1Σ+g)→HCl(X 1Σ+)+Cl(2P) and Cl(2P)+HCl(X 1Σ+)→HCl(X 1Σ+)+Cl(2P) gas phase elementary chemical reactions. The former reaction is an important chemical laser while the second one is the most frequently used prototype of heavy-light-heavy reaction. A large number of points on the 2A′ PES have been calculated at the PUMP2/6-311G(3d2 f,3p2d) ab initio level. The ab initio calculations show the existence of two angular transition states with negligible or very small barriers to collinearity. This and other properties of the PES are in agreement with previous studies. An analytical expression based on a many-body expansion has been used to obtain a satisfactory fit of the 740 ab initio points calculated, with a root-mean-square deviation within the range of the estimated ab initio method error margin. This analytical representation of the 2A′ PES has been used to evaluate the variational transition state theory thermal rate constants of the above-mentioned reactions, including also the Cl+DCl reaction, and quite good agreement has been obtained when comparing with experimental results. The analytical PES obtained in this work is suitable for use in studies on the kinetics and dynamics of the HCl2 system
Problemes orals en un grup de nens amb leucèmia limfoblàstica aguda
La leucèmia limfoblàstica aguda (LLA) és principalment una malaltia infantil, les manifestacions bucals de la qual són molt importants per la seva alta incidència i també perquè poden constituir la primera localització ostensible de la malaltia. S'ha dut a terme un estudi sobre un grup d'onze pacients del Servei d'Hematooncologia de l'Hospital Universitari Materno-Infantil Vall d'Hebron de Barcelona, afectats per LLA, realitzant un examen oral en el qual es presta atenció especial a les lesions relacionades amb la LLA o amb el tractament que rebien els pacients. L'edat deis pacients oscil·la entre els 2 i els 14 anys i l'estat de la malaltia va des de LLA recentment diagnosticades i en tractament de quimioteràpia d'inducció fins a pacients no hospitalitzats en els quals ja s'havia suprimit el tractament. Fer notar la inexistència de casos amb simptomatologia oral molt florida degut a les extenses cures que reben els pacients al Servei d'Hematooncologia i a l'excel·lent programa preventiu establert per a ells, que inclou la profilaxi antifúngica i de mucositis. Es destaquen d'entre els signes la pal·lidesa oral, úlceres i lesions hemàtiques tipus equimosi i petèquies
Lanthanide tetrazolate complexes combining single-molecule magnet and luminescence properties: the effect of the replacement of tetrazolate n3 by β-diketonate ligands on the anisotropy energy barrier
Three new sets of mononuclear LnIII complexes of general formulas [LnL3]⋅CH3OH [LnIII=Yb (1), Er (2), Dy (3), Gd (4), and Eu (5)], [LnL2(tmh)(CH3OH)]⋅n H2O⋅m CH3OH [LnIII=Yb (1 b), Er (2 b), Dy (3 b), Gd (4 b)], and [LnL2(tta)(CH3OH)]⋅CH3OH [LnIII=Yb (1 c), Er (2 c), Dy (3 c), Gd (4 c)] were prepared by the reaction of Ln(CF3SO3)⋅n H2O salts with the tridentate ligand 2-(tetrazol-5-yl)-1,10-phenanthroline (HL) and, for the last two sets, additionally with the β-diketonate ligands 2,2,6,6-tetramethylheptanoate (tmh) and 2-thenoyltrifluoroacetonate (tta), respectively. In the [LnL3]⋅CH3OH complexes the LnIII ions are coordinated to three phenanthroline tetrazolate ligands with an LnN9 coordination sphere. Dynamic ac magnetic measurements on 1–3 reveal that these complexes only exhibit single-molecule magnet (SMM) behavior when an external dc magnetic field is applied, with Ueff values of 11.7 K (1), 16.0 K (2), and 20.2 K (3). When the tridentate phenanthroline tetrazolate ligand is replaced by one molecule of methanol and the β-diketonate ligand tmh (1 b–3 b) or tta (1 c–3 c), a significant increase in Ueff occurs and, in the case of the DyIII complexes 3 b and 3 c, out-of-phase χ′′ signals below 15 and 10 K, respectively, are observed in zero dc magnetic field. CASSCF+RASSI ab initio calculations performed on the DyIII complexes support the experimental results. Thus, for 3 the ground Kramers’ doublet is far from being axial and the first excited state is found to be very close in energy to the ground state, so the relaxation barrier in this case is almost negligible. Conversely, for 3 b and 3 c, the ground Kramers’ doublet is axial with a small quantum tunneling of the magnetization, and the energy difference between the ground and first Kramers’ doublets is much higher, which allows these compounds to behave as SMMs at zero field. Moreover, these calculations support the larger Ueff observed for 3 b compared to 3 c. Additionally, the solid-state photophysical properties of 1, 2, 4, and 5 show that the phenanthroline tetrazolate ligand can act as an effective antenna to sensitize the characteristic YbIII, ErIII, and EuIII emissions through an energy-transfer process
Frontispiece: Lanthanide tetrazolate complexes combining single-molecule magnet and luminescence properties: The effect of the replacement of tetrazolate N3 by β-Diketonate Ligands on the anisotropy energy barrier
Three new sets of mononuclear LnIII complexes of general formulas [LnL3]·CH3OH
(LnIII = Yb (1), Er (2), Dy (3), Gd (4) and Eu (5)), [LnL2(tmh)(CH3OH)]·n H2O·m
CH3OH (LnIII = Yb (1b), Er (2b), Dy (3b), Gd (4b)) and [LnL2(tta)(CH3OH)]·CH3OH
(LnIII = Yb (1c), Er (2c), Dy (3c), Gd (4c) have been prepared from the reaction of
Ln(CF3SO3)·nH2O salts with the tridentate ligand 2-(tetrazolate-5-yl)-1,10-
phenanthroline (HL). For the two latter sets, additionally with the respective β-
diketonate ligands 2,2,6,6-tetramethylheptanoate (tmh) or 2-thenoyltrifluoroacetonate
(tta). In the [LnL3]·CH3OH complexes the LnIII ions are coordinated to three
phenanthroline-tetrazolate ligands showing a LnN9 coordination sphere. Dynamic ac
magnetic measurements for 1 – 3 reveal that these complexes only exhibit single
molecule magnet (SMM) behaviour when an external dc magnetic field is applied, with
Ueff values of 11.7 K (1), 16.0 K (2) and 20.2 K (3). When the tridentate phenanthrolinetetrazolate
ligand is replaced by one molecule of methanol and the β-diketonate ligand tmh (1b – 3b) or tta (1c – 3c), a significant increase in Ueff occurs and, in the case of the
DyIII derivates 3b and 3c, out-of-phase χ’’ signals below 15 K and 10 K, respectively,
are observed under zero-dc magnetic field. CASSCF+RASSI ab initio calculations
performed on the DyIII derivates support the experimental results. Thus, for 3 the ground
Kramers’ doublet is far from being axial and the first excited state is found to be very close in energy to the ground state so the relaxation barrier in this case is almost
negligible. Conversely, for 3b and 3c, the ground Kramers’ doublet is axial with a small
quantum tunneling of the magnetization (QTM) and the energy difference between the
ground and first Kramers’ doublets is much higher, which allows these compounds to
behave as SMMs at zero-field. Moreover, these calculations support the larger Ueff
observed for 3b compared to 3c. Additionally, the solid-state photophysical properties
of 1, 2, 4 and 5 show that the phenanthroline tetrazolate ligand can act as an effective
antenna to sensitize the characteristic YbIII, ErIII and EuIII emissions through an energy
transfer process
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