Probing the ISM Near Star Forming Regions with GRB Afterglow Spectroscopy: Gas, Metals, and Dust

We study the chemical abundances of the interstellar medium surrounding high z gamma-ray bursts (GRBs) through analysis of the damped Lya systems (DLAs) identified in afterglow spectra. These GRB-DLAs are characterized by large HI column densities N(HI) and metallicities [M/H] spanning 1/100 to nearly solar, with median [M/H]>-1. The majority of GRB-DLAs have [M/H] values exceeding the cosmic mean metallicity of atomic gas at z>2, i.e. if anything, the GRB-DLAs are biased to larger metallicity. We also observe (i) large [Zn/Fe] values (>+0.6) and sub-solar Ti/Fe ratios which imply substantial differential depletion, (ii) large a/Fe ratios suggesting nucleosynthetic enrichment by massive stars, and (iii) low C^0/C^+ ratios (<10^{-4}). Quantitatively, the observed depletion levels and C^0/C^+ ratios of the gas are not characteristic of cold, dense HI clouds in the Galactic ISM. We argue that the GRB-DLAs represent the ISM near the GRB but not gas directly local to the GRB (e.g. its molecular cloud or circumstellar material). We compare these observations with DLAs intervening background quasars (QSO-DLAs). The GRB-DLAs exhibit larger N(HI) values, higher a/Fe and Zn/Fe ratios, and have higher metallicity than the QSO-DLAs. We argue that the differences primarily result from galactocentric radius-dependent differences in the ISM: GRB-DLAs preferentially probe denser, more depleted, higher metallicity gaslocated in the inner few kpc whereas QSO-DLAs are more likely to intersect the less dense, less enriched, outer regions of the galaxy. Finally, we investigate whether dust obscuration may exclude GRB-DLA sightlines from QSO-DLA samples; we find that the majority of GRB-DLAs would be recovered which implies little observational bias against large N(HI) systems.Comment: 16 pages, 9 figures. Submitted to Ap

The Formation and Application of Polymeric Micro- and Nanoparticles

Nano- and microparticles are used in the pharmaceutical industry for sustained release drug delivery systems. For example, polymeric particles are currently used as an FDA-approved drug delivery system for leuprolide acetate to treat prostate cancer1. Our drug of interest is CPDI-02 (formerly known as EP67)—a C5a-derived decapeptide agonist of the C5a Receptor (CD88) that activates mononuclear phagocytes to produce an immune response while potentially minimizing neutrophil-mediated toxicity2. Currently in the Vetro Lab, CPDI-02 is being tested on pigs and mice to treat methicillin-resistant Staphylococcus aureus (MRSA) infections and as the adjuvant for a vaccine for cytomegalovirus (CMV). This investigation explored formulation parameters that impact particle size and loading of CPDI-02 in a traditional oil-in-water (O/W) emulsion. We also explored adapting the formulation using microfluidic chips to generate nano- and microparticles and improve run-to-run consistency in particle size.https://digitalcommons.unmc.edu/surp2022/1004/thumbnail.jp

Symptoms of Paranoia Experienced by Students of Pakistani Heritage in England: The Role of Explicit and Implicit Identities and Perceived Discrimination

ABSTRACT: Individuals belonging to ethnic minority groups are less likely to experience symptoms of psychosis, such as paranoia, if they live in areas with high proportions of people from the same ethnic background. This effect may be due to processes associated with group belonging (social identification). We examined whether the relationship between perceived discrimination and paranoia was moderated by explicit and implicit Pakistani/English identification among students of Pakistani heritage (N = 119). Participants completed measures of explicit and implicit Pakistani and English identity, a measure of perceived discrimination, and a measure of paranoia. Perceived discrimination was the strongest predictor of paranoia (0.31). Implicit identities moderated the relationship between perceived discrimination and paranoia (-0.17). The findings suggest that higher levels of implicit Pakistani identity were most protective against high levels of paranoia (0.26, with low implicit English identity; 0.78, with medium English identity; 1.46, with high English identity). Overall, a complex relationship between identity and paranoia was apparent

Gestational and Chronic Low-Dose PFOA Exposures and Mammary Gland Growth and Differentiation in Three Generations of CD-1 Mice

Background: Prenatal exposure to perfluorooctanoic acid (PFOA), a ubiquitous industrial surfactant, has been reported to delay mammary gland development in female mouse offspring (F1) and the treated lactating dam (P0) after gestational treatments at 3 and 5 mg PFOA/kg/day

The Current Energetics of Earth's Interior: A Gravitational Energy Perspective

The Earth's mantle convects to lose heat (Holmes, 1931); doing so drives plate tectonics (Turcotte and Oxburgh, 1967). Significant gravitational energy is created by the cooling of oceanic lithosphere atop hotter, less dense mantle. When slabs subduct, this gravitational energy is mostly (~86% for whole mantle flow in a PREM-like mantle) transformed into heat by viscous dissipation. Using this perspective, we reassess the energetics of Earth's mantle. We also reconsider the terrestrial abundances of heat producing elements U, Th, and K, and argue they are lower than previously considered and that consequently the heat produced by radioactive decay within the mantle is comparable to the present-day potential gravitational energy release by subducting slabs—both are roughly ~10–12 TW. We reassess possible core heat flow into the base of the mantle, and determine that the core may be still losing a significant amount of heat from its original formation, potentially more than the radioactive heat generation within the mantle. These factors are all likely to be important for Earth's current energetics, and argue that strong plume-driven upwelling is likely to exist within the convecting mantle

Cyclin D2-knock-out mice with attenuated dentate gyrus neurogenesis have robust deficits in long-term memory formation.

Neurobehavioral studies have produced contradictory findings concerning the function of neurogenesis in the adult dentate gyrus. Previous studies have proved inconsistent across several behavioral endpoints thought to be dependent on dentate neurogenesis, including memory acquisition, short-term and long-term retention of memory, pattern separation, and reversal learning. We hypothesized that the main function of dentate neurogenesis is long-term memory formation because we assumed that a newly formed and integrated neuron would have a long-term impact on the local neural network. We used a cyclin D2-knock-out (cyclin D2-/-) mouse model of endogenously deficient dentate neurogenesis to test this hypothesis. We found that cyclin D2-/- mice had robust and sustained loss of long-term memory in two separate behavioral tasks, Morris water maze (MWM) and touchscreen intermediate pattern separation. Moreover, after adjusting for differences in brain volumes determined by magnetic resonance (MR) imaging, reduced dentate neurogenesis moderately correlated with deficits in memory retention after 24 hours. Importantly, cyclin D2-/- mice did not show deficits in learning acquisition in a touchscreen paradigm of intermediate pattern separation or MWM platform location, indicating intact short-term memory. Further evaluation of cyclin D2-/- mice is necessary to confirm that deficits are specifically linked to dentate gyrus neurogenesis since cyclin D2-/- mice also have a reduced size of the olfactory bulb, hippocampus, cerebellum and cortex besides reduced dentate gyrus neurogenesis

Natural hazards in Australia : storms, wind and hail

Current and potential future storm-related wind and hail hazard in Australia is reviewed. Confidence in the current incidence of wind hazard depends upon the type of storm producing the hazard. Current hail hazard is poorly quantified in most regions of Australia. Future projections of wind hazard indicate decreases in wind hazard in northern Australia, increases along the east coast and decreases in the south, although such projections are considerably uncertain and are more uncertain for small-scale storms than for larger storms. A number of research gaps are identified and recommendations made