1,540 research outputs found
Excited states of beryllium atom from explicitly correlated wave functions
A study of the first excited states of beryllium atom starting from
explicitly correlated wave functions is carried out. Several properties are
obtained and discussed focusing on the analysis of the Hund's rules in terms of
the single--particle and electron pair intracule and extracule densities. A
systematic study of the differences on the electronic distributions of the
singlet and triplet states is carried out. The trial wave function used to
describe the different bound states consists of a generalized Jastrow-type
correlation factor times a configuration interaction model wave function. This
model wave function has been fixed by using a generalization of the optimized
effective potential method to deal with multiconfiguration wave functions. The
optimization of the wave function and the calculation of the different
quantities is carried out by means of the Variational Monte Carlo method.Comment: 28 pages, 6 figure
Assessment of global sensitivity analysis methods for project scheduling
Product development requires scheduling that considers the interdependence between activities. The definition of the interdependencies and duration of activities, communication times and the level of overlap between activities is needed for project scheduling. However, these parameters have epistemic uncertainties that can affect project scheduling. In this work, different global sensitivity analysis techniques were applied to identify the parameters that had the greatest effect on project scheduling. It was concluded that standardized regression coefficients as well as the Morris and Sobol Jansen methods were the most appropriate. It was also found that global sensitivity analysis can help to focus resources
based on the definitions and control the uncertainty of key activities. Furthermore, it was concluded that control of the uncertainty of key activities reduces the uncertainty and duration of projects.Galvez, ED.; Capuz-Rizo, SF. (2016). Assessment of global sensitivity analysis methods for project scheduling. Computers and Industrial Engineering. 93:110-120. doi:10.1016/j.cie.2015.12.010S1101209
Leadership in Public Health: Provider Perspectives
The role of public health leaders in shaping decision- and policymaking remains a critical task that encompasses many qualities. The current report attempts to capture the perspectives about this task from those working in the community in Hawai‘i. Methods: This is a qualitative descriptive study design. Participants (n=115; 84.3% female; mean age=42.3 [SD = 12.3] years) generated lists of qualities they identified as critical for leadership and developed definitions of a public health leader. Data were coded thematically. Rating differences were subsequently discussed and converged to 100% interrater reliability in thematic ratings. Results: The most often cited theme in the leadership qualities highlighted a more general skill set, including organizational ability, being reliable, and being consistent (N=29, 25.44%). The most cited theme amongst the definitions was the ability to work with others and bring a team together (N=37, 31.09%). Of note are several differences from the literature, including having a community orientation, impact, integrity, and being a strategic thinker. Conclusion: The awareness of these perspectives and ability to integrate this information into one’s personal leadership style may help shape those individuals hoping to lead the field in the future
Securing the Post-Covid Pharma Supply Chain: An Empirical Investigation
The pandemic outbreak of Covid-19 has shown the fragilities and vulnerabilities of the Pharma Supply Chain (PSC), leading academics and practitioners to rethink PSCs’ flexibility, agility, responsiveness, and resilience. This paper investigates how to secure the Post-Covid PSC by (i) classifying the challenges born of or aggravated by the pandemic; (ii) understanding how solutions enabled by Industry 4.0 technologies can be integrated into a framework to address and solve the above challenges. A theoretical framework was developed from a literature review to achieve these objectives, which was then confirmed and enriched by a multiple case study investigation
Primeval very low-mass stars and brown dwarfs - VI. Population properties of metal-poor degenerate brown dwarfs
© 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.We presented 15 new T dwarfs that were selected from UKIRT Infrared Deep Sky Survey, Visible and Infrared Survey Telescope for Astronomy, and Wide-field Infrared Survey Explorer surveys, and confirmed with optical to near infrared spectra obtained with the Very Large Telescope and the Gran Telescopio Canarias. One of these new T dwarfs is mildly metal-poor with slightly suppressed -band flux. We presented a new X-shooter spectrum of a known benchmark sdT5.5 subdwarf, HIP 73786B. To better understand observational properties of brown dwarfs, we discussed transition zones (mass ranges) with low-rate hydrogen, lithium, and deuterium burning in brown dwarf population. The hydrogen burning transition zone is also the substellar transition zone that separates very low-mass stars, transitional, and degenerate brown dwarfs. Transitional brown dwarfs have been discussed in previous works of the Primeval series. Degenerate brown dwarfs without hydrogen fusion are the majority of brown dwarfs. Metal-poor degenerate brown dwarfs of the Galactic thick disc and halo have become T5+ subdwarfs. We selected 41 T5+ subdwarfs from the literature by their suppressed -band flux. We studied the spectral-type - colour correlations, spectral-type - absolute magnitude correlations, colour-colour plots, and HR diagrams of T5+ subdwarfs, in comparison to these of L-T dwarfs and L subdwarfs. We discussed the T5+ subdwarf discovery capability of deep sky surveys in the 2020s.Peer reviewe
Biomarkers of Aryl-hydrocarbon Receptor Activity in Gulf Killifish (Fundulus grandis) From Northern Gulf of Mexico Marshes Following the Deepwater Horizon Oil Spill
© 2017, Springer Science+Business Media New York. Following the Deepwater Horizon oil spill, shorelines throughout the Barataria Basin of the northern Gulf of Mexico in Louisiana were heavily oiled for months with Macondo-252 oil, potentially impacting estuarine species. The Gulf killifish (Fundulus grandis) has been identified as a sentinel species for the study of site-specific effects of crude oil contamination on biological function. In November and December 2010, 4–5 months after the Macondo well was plugged and new oil was no longer spilling into the Gulf waters, Gulf killifish were collected across the Barataria Basin from 14 sites with varying degrees of oiling. Fish collected from oiled sites exhibited biological indications of exposure to oil, including increase in cytochrome P4501A (CYP1A) mRNA transcript and protein abundances in liver tissues. Immunohistochemistry revealed increases in gill, head kidney, and intestinal CYP1A protein at heavily oiled sites. Intestinal CYP1A protein was a sensitive indicator of exposure, indicating that intestinal tissue plays a key role in biotransformation of AHR ligands and that ingestion is a probable route of exposure, warranting additional consideration in future studies
Localization and characterization of phenamil-sensitive Na\u3csup\u3e+\u3c/sup\u3e influx in isolated rainbow trout gill epithelial cells
Percoll density-gradient separation, combined with peanut lectin agglutinin (PNA) binding and magnetic bead separation, was used to separate dispersed fish gill cells into sub-populations. Functional characterization of each of the sub-populations was performed to determine which displayed acid-activated phenamil- and bafilomycin-sensitive Na+ uptake. Analysis of the mechanism(s) of 22Na+ influx was performed in control and acid-activated (addition of 10 mmoll-1 proprionic acid) cells using a variety of Na+ transport inhibitors (ouabain, phenamil, HOE-694 and bumetanide) and a V-type ATPase inhibitor (bafilomycin). We found that cells migrating to a 1.03-1.05 g ml-1 Percoll interface [pavement cells (PVCs)] possessed the lowest rates of Na+ uptake and that influx was unchanged during either bafilomycin (10 nmoll-1) treatment or internal acidification with addition of proprionic acid (10 mmoll-1). Mitochondria-rich (MR) cells that migrated to the 1.05-1.09 g ml-1 interface of the Percoll gradient demonstrated acidification-activated bafilomycin and phenamil-sensitive Na+ influx. Further separation of the MR fraction into PNA+ and PNA- fractions using magnetic separation demonstrated that only the PNA- cells (α-MR cells) demonstrated phenamiland bafilomycin-sensitive acid-activated 22Na+ uptake. We confirm the coupling of a V-type H+-ATPase with phenamil-sensitive Na+ uptake activity and conclude that high-density α-MR cells function in branchial Na+ uptake in freshwater fish
Spin-induced angular momentum switching
When light is transmitted through optically inhomogeneous and anisotropic
media the spatial distribution of light can be modified according to its input
polarization state. A complete analysis of this process, based on the paraxial
approximation, is presented, and we show how it can be exploited to produce a
spin-controlled-change in the orbital angular momentum of light beams
propagating in patterned space-variant-optical-axis phase plates. We also
unveil a new effect. The development of a strong modulation in the angular
momentum change upon variation of the optical path through the phase plates.Comment: The original paper of the published version in Opt. Let
Functional genomics of physiological plasticity and local adaptation in killifish
Evolutionary solutions to the physiological challenges of life in highly variable habitats can span the continuum from evolution of a cosmopolitan plastic phenotype to the evolution of locally adapted phenotypes. Killifish (Fundulus sp.) have evolved both highly plastic and locally adapted phenotypes within different selective contexts, providing a comparative system in which to explore the genomic underpinnings of physiological plasticity and adaptive variation. Importantly, extensive variation exists among populations and species for tolerance to a variety of stressors, and we exploit this variation in comparative studies to yield insights into the genomic basis of evolved phenotypic variation. Notably, species of Fundulus occupy the continuum of osmotic habitats from freshwater to marine and populations within Fundulus heteroclitus span far greater variation in pollution tolerance than across all species of fish. Here, we explore how transcriptome regulation underpins extreme physiological plasticity on osmotic shock and how genomic and transcriptomic variation is associated with locally evolved pollution tolerance. We show that F. heteroclitus quickly acclimate to extreme osmotic shock by mounting a dramatic rapid transcriptomic response including an early crisis control phase followed by a tissue remodeling phase involving many regulatory pathways. We also show that convergent evolution of locally adapted pollution tolerance involves complex patterns of gene expression and genome sequence variation, which is confounded with body-weight dependence for some genes. Similarly, exploiting the natural phenotypic variation associated with other established and emerging model organisms is likely to greatly accelerate the pace of discovery of the genomic basis of phenotypic variation. The American Genetic Association. 2010. All rights reserved. For permissions, please email: [email protected] © The American Genetic Association. 2010. All rights reserved. For permissions, please email: [email protected]
- …