The Molecular Line Opacity of MgH in Cool Stellar Atmospheres

A new, complete, theoretical rotational and vibrational line list for the A-X electronic transition in MgH is presented. The list includes transition energies and oscillator strengths for all possible allowed transitions and was computed using the best available theoretical potential energies and dipole transition moment function with the former adjusted to account for experimental data. The A-X line list, as well as new line lists for the B'-X and the X-X (pure rovibrational) transitions, were included in comprehensive stellar atmosphere models for M, L, and T dwarfs and solar-type stars. The resulting spectra, when compared to models lacking MgH, show that MgH provides significant opacity in the visible between 4400 and 5600 Angstrom. Further, comparison of the spectra obtained with the current line list to spectra obtained using the line list constructed by Kurucz (1993) show that the Kurucz list significantly overestimates the opacity due to MgH particularly for the bands near 5150 and 4800 Angstrom with the discrepancy increasing with decreasing effective temperature.Comment: 10 pages, 4 figures, 3 table

A Contribution to the study of the Fauna of Ukwere Island, victoria Nyanza (Col., Curculionidae; Apioninae)

Volume: XVII

Testing And Verification For The Open Source Release Of The Horizon Simulation Framework

Modeling and simulation tools are exceptionally useful for designing aerospace systems because they allow engineers to test and iterate designs before committing the massive resources required for system realization. The Horizon Simulation Framework (HSF) is a time-driven modeling and simulation tool which attempts to optimize how a modeled system could perform a mission profile. After 15 years of development, the HSF team aims to achieve a wider user and developer base by releasing the software open source. To ensure a successful release, the software required extensive testing, and the main scheduling algorithm required protections against new code breaking old functionality. The goal of the work presented in this thesis is to satisfy these requirements and officially release the software open source. The software was tested with \u3e 80% coverage and a continuous integration pipeline which runs build and unit/integration tests on every new commit was set up. Finally, supporting documentation and user resources were created and organized to promote community adoption of the software, making Horizon ready for an open source release

An Arab Physician on Insanity

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The Molecular Continuum Opacity of MgH in Cool Stellar Atmospheres

The opacity due to photodissociation of 24MgH is investigated in the atmospheres of cool stars. The lowest two electronic transitions A 2Pi -- X 2Sigma+ and B' 2Sigma+ -- X 2 Sigma+ are considered where the cross sections for the latter were published previously (Weck, Stancil, & Kirby 2002) while the former are presented in this work. Model atmospheres calculated with the PHOENIX code are used to investigate the effect of the photodissociation opacity on spectra of cool stars. The A -- X photodissociation cross sections are obtained using a combination of ab initio and experimentally derived potential curves and dipole transition moments. Partial cross sections have been evaluated over the accessible wavelength range 1770-4560 Angstrom for all rotational transitions from the vibrational levels v''=0-11. Assuming a Boltzmann distribution of the rovibrational levels of the X 2Sigma+ state, LTE photodissociation cross sections are presented for temperatures between 1000 and 5000 K. Shape resonances, arising from rotational predissociation of quasi-bound levels of the A 2Pi state near threshold, characterize the LTE photodissociation cross sections. A sum rule is proposed as a check on the accuracy of the photodissociation calculations.Comment: 9 pages, 8 figure

Appetite for self-destruction: suicidal biting as a nest defense strategy in Trigona stingless bees

Self-sacrificial behavior represents an extreme and relatively uncommon form of altruism in worker insects. It can occur, however, when inclusive fitness benefits are high, such as when defending the nest. We studied nest defense behaviors in stingless bees, which live in eusocial colonies subject to predation. We introduced a target flag to nest entrances to elicit defensive responses and quantified four measures of defensivity in 12 stingless bee species in São Paulo State, Brazil. These included three Trigona species, which are locally known for their aggression. Species varied significantly in their attack probability (cross species range = 0–1, P < 0.001), attack latency (7.0–23.5 s, P = 0.002), biting duration of individual bees (3.5–508.7 s, P < 0.001), and number of attackers (1.0–10.8, P < 0.001). A “suicide” bioassay on the six most aggressive species determined the proportion of workers willing to suffer fatal damage rather than disengage from an intruder. All six species had at least some suicidal individuals (7–83 %, P < 0.001), reaching 83 % in Trigona hyalinata. Biting pain was positively correlated with an index of overall aggression (P = 0.002). Microscopic examination revealed that all three Trigona species had five sharp teeth per mandible, a possible defensive adaptation and cause of increased pain. Suicidal defense via biting is a new example of self-sacrificial altruism and has both parallels and differences with other self-sacrificial worker insects, such as the honey bee. Our results indicate that suicidal biting may be a widespread defense strategy in stingless bees, but it is not universal

NOC Liverpool report for the Wirewalker underwater profiler deployment for the RidgeMix research programme

This report provides a review of a ‘wirewalker’ underwater profiler that was used for high resolution water quality and turbulence measurements as part of a mid-Atlantic ocean based scientific survey. The profiler utilised wave energy and buoyancy to generate automated, cyclic underwater vertical measurements. A drifting supporting surface buoy and mooring configuration was used that moved horizontally in response to underwater currents, surface wind and waves, while generating repeated sub-surface vertical scientific measurements. The profiler instrumentation payload included a high-resolution chlorophyll-a fluorimeter, a fast sampling, precision conductivity, temperature and depth sensor (CTD) and a fragile, high resolution oceanic microstructure and turbulence sensor. A bespoke guard was used to help protect the fragile microstructure and turbulence sensors from damage. The mooring surface buoy instrumentation included telemetered GPS at nominally 30 minute intervals, a backup telemetered position indication, a VHF radio beacon based position locator and a solar powered night time light. The experiment was designed to resolve time-variability of upper-ocean mixing and chlorophyll-a fluorescence over the Mid-Atlantic underwater Ridge, an internal wave generation hotspot. Typically more than three wave driven descents to 200 metres and subsequent buoyancy driven ascents to close to the sea surface were achieved per hour during a 22 day deployment, whilst continuously sampling. This represents the first time the UK National Oceanography Centre (NOC) have used this type of underwater profiling system for high resolution oceanic microstructure and turbulence measurements to support a scientific campaign. Information to support a series of developing operational best practices for the use of this delicate and precision sensing arrangement with a wirewalker underwater profiler is provided. Recommendations relating to the future development of this versatile measurement system are also discussed

Range-separated density-functional theory with random phase approximation: detailed formalism and illustrative applications

Using Green-function many-body theory, we present the details of a formally exact adiabatic-connection fluctuation-dissipation density-functional theory based on range separation, which was sketched in Toulouse, Gerber, Jansen, Savin and Angyan, Phys. Rev. Lett. 102, 096404 (2009). Range-separated density-functional theory approaches combining short-range density functional approximations with long-range random phase approximations (RPA) are then obtained as well-identified approximations on the long-range Green-function self-energy. Range-separated RPA-type schemes with or without long-range Hartree-Fock exchange response kernel are assessed on rare-gas and alkaline-earth dimers, and compared to range-separated second-order perturbation theory and range-separated coupled-cluster theory.Comment: 15 pages, 3 figures, 2 table

Shining new light on mammalian diving physiology using wearable near-infrared spectroscopy

Investigation of marine mammal dive-by-dive blood distribution and oxygenation has been limited by a lack of non-invasive technology for use in freely diving animals. Here, we developed a non-invasive near-infrared spectroscopy (NIRS) device to measure relative changes in blood volume and haemoglobin oxygenation continuously in the blubber and brain of voluntarily diving harbour seals. Our results show that seals routinely exhibit preparatory peripheral vasoconstriction accompanied by increased cerebral blood volume approximately 15 s before submersion. These anticipatory adjustments confirm that blood redistribution in seals is under some degree of cognitive control that precedes the mammalian dive response. Seals also routinely increase cerebral oxygenation at a consistent time during each dive, despite a lack of access to ambient air. We suggest that this frequent and reproducible reoxygenation pattern, without access to ambient air, is underpinned by previously unrecognised changes in cerebral drainage. The ability to track blood volume and oxygenation in different tissues using NIRS will facilitate a more accurate understanding of physiological plasticity in diving animals in an increasingly disturbed and exploited environment