Search results for "Modeling"
showing 10 items of 4489 documents
Limited effects of size-selective harvesting and harvesting-induced life-history changes on the temporal variability of biomass dynamics in complex f…
2023
Harvesting has been implicated in destabilizing the abundances of exploited populations. Because selective harvesting often targets large individuals, some studies have proposed that exploited populations often experience demographic shifts toward younger, smaller individuals and become more sensitive to environmental fluctuations. The theory of consumer–resource dynamics has been applied to address the impacts of harvesting in simple modular food webs, but harvested populations are embedded in a complex food web in nature. In addition, exploited populations have been shown to undergo trait evolution or phenotypic changes toward early maturation at smaller sizes. Using an empirically derive…
Fracture Shape and Orientation Contributions to P-Wave Velocity and Anisotropy of Alpine Fault Mylonites
2021
P-wave anisotropy is significant in the mylonitic Alpine Fault shear zone. Mineral- and texture-induced anisotropy are dominant in these rocks but further complicated by the presence of fractures. Electron back-scattered diffraction and synchrotron X-ray microtomography (micro-CT) data are acquired on exhumed schist, protomylonite, mylonite and ultramylonite samples to quantify mineral phases, crystal preferred orientations, microfractures and porosity. The samples are composed of quartz, plagioclase, mica and accessory garnet, and contain 3-5% porosity. Based on the micro-CT data, the representative pore shape has an aspect ratio of 5:2:1. Two numerical models are compared to calculate the…
Improved calculations of beta decay backgrounds to new physics in liquid xenon detectors
2020
We present high-precision theoretical predictions for the electron energy spectra for the ground-state to ground-state $\beta$ decays of $^{214}$Pb, $^{212}$Pb, and $^{85}$Kr most relevant to the background of liquid xenon dark matter detectors. The effects of nuclear structure on the spectral shapes are taken into account using large-scale shell model calculations. Final spectra also include atomic screening and exchange effects. The impact of nuclear structure effects on the $^{214}$Pb and $^{212}$Pb spectra below $\approx100$ keV, pertinent for several searches for new physics, are found to be comparatively larger than those from the atomic effects alone. We find that the full calculatio…
Optimal control in models with conductive‐radiative heat transfer
2003
In this paper an optimal control problem for the elliptic boundary value problem with nonlocal boundary conditions is considered. It is shown that the weak solutions of the boundary value problem depend smoothly on the control parameter and that the cost functional of the optimal control problem is Frechet differentiable with respect to the control parameter. Optimalus valdymas modeliuose su laidžiu-radioaktyviu šilumos pernešimu Santrauka Darbe nagrinejamas nelokalaus kraštinio uždavinio optimalaus valdymo uždavinys. Parodyta, kad silpnasis kraštinio uždavinio sprendinys tolydžiai priklauso nuo valdomojo parametro, taigi, optimalaus valdymo tikslo funkcija yra diferencijuojama Freše prasme…
Removal of bis(2-ethylhexyl) phthalate at a sewage treatment plant
2003
Bis(2-ethylhexyl) phthalate (DEHP) concentrations were measured at different stages in a full-scale sewage treatment plant (STP) and mass balances were calculated. The DEHP load to treatment process coming from the sewer system and the internal load comprising returned supernatants and filtrate from sludge treatment and excess secondary sludge were at the same level. The DEHP removal efficiency from the water phase at the STP was on average 94% of sewage DEHP, the main removal process being sorption to primary and secondary sludges. On average 29% of DEHP was calculated to be removed in the biological nitrifying-denitrifying activated sludge process, which was much less than expected from l…
Nuclear receptor NR5A2 and bone: gene expression and association with bone mineral density
2011
El pdf del artículo es el manuscrito de autor (PMCID: PMC3682472).-- et al.
Analysis of Social Media Impact on Opportunity Recognition. A Social Networks and Entrepreneurial Alertness Mixed Approach
2020
This paper investigates the effects of social media on entrepreneurial opportunity recognition. Combining the internal and external approaches of opportunity recognition, the study analyzes how social media influences the entrepreneurs in discovering new entrepreneurial opportunities. Structural equation modeling was used in this study, using the variance-based partial least squares (PLS)&ndash
Molecular docking and oxidation kinetics of 3-phenyl coumarin derivatives by human CYP2A13
2021
CYP2A13 enzyme is expressed in human extrahepatic tissues, while CYP2A6 is a hepatic enzyme. Reactions catalysed by CYP2A13 activate tobacco-specific nitrosamines and some other toxic xenobiotics in lungs.To compare oxidation characteristics and substrate-enzyme active site interactions in CYP2A13 vs CYP2A6, we evaluated CYP2A13 mediated oxidation characteristics of 23 coumarin derivatives and modelled their interactions at the enzyme active site.CYP2A13 did not oxidise six coumarin derivatives to corresponding fluorescent 7-hydroxycoumarins. The Km-values of the other coumarins varied 0.85���97 ��M, Vmax-values of the oxidation reaction varied 0.25���60 min���1, and intrinsic clearance var…
Candida antarctica Lipase A-Based Enantiorecognition of a Highly Strained 4-Dibenzocyclooctynol (DIBO) Used for PET Imaging
2020
The enantiomers of aromatic 4-dibenzocyclooctynol (DIBO), used for radiolabeling and subsequent conjugation of biomolecules to form radioligands for positron emission tomography (PET), were separated by kinetic resolution using lipase A from Candida antarctica (CAL-A). In optimized conditions, (R)-DIBO [(R)-1, ee 95%] and its acetylated (S)-ester [(S)-2, ee 96%] were isolated. In silico docking results explained the ability of CAL-A to differentiate the enantiomers of DIBO and to accommodate various acyl donors. Anhydrous MgCl2 was used for binding water from the reaction medium and, thus, for obtaining higher conversion by preventing hydrolysis of the product (S)-2 into the starting materi…
Propiedades psicométricas de la versión española de la Escala Temporal de Satisfacción con la Vida (Temporal Satisfaction With Life Scale, TSLS): Un …
2015
Para la operacionalización del bienestar se han desarrollado un gran número de medidas, destacando la Escala de Satisfacción con la Vida (SWLS). Para paliar algunos de sus problemas, se desarrolló la Escala Temporal de Satisfacción con la Vida (TSLS). El objetivo de este estudio es la presentación y primera validación de la TSLS en su versión española, en una muestra de personas mayores que acuden a programas universitarios. La muestra estaba formada por 737 personas mayores. Además de la TSLS, se empleó un indicador de satisfacción general con la vida y la SF-8. Los análisis incluyeron estudio de la validez factorial, estimaciones de la fiabilidad y de validez externa. Los resultados del a…