Star clusters are key age-dateable tracers of the chemical history of the Milky Way. Star clusters can provide significant constraints on galaxy chemical evolution models. The large discrepancies between different small studies limit the accuracy of these constraints, so a large uniform study is needed. To create a large uniform sample, we observed stars in 63 clusters with the same telescope. We then determined the chemical makeup of these stars using a machine learning tool called The Cannon. Using this sample, we examine the change in chemical abundance over the radius of our galaxy.

Nano- and microcrystalline ZnO is a low-cost material, employed in many applications due to its optoelectronic, structural and chemical properties as well as a great variety of synthesis methods. Among these applications, antibacterial action of ZnO is a budding field of interdisciplinary research. Despite numerous studies of this antibacterial action, the physical and chemical mechanisms behind it are still largely not understood. In particular, the influence of the crystal surface morphology and surface-surface interactions between the bacteria and ZnO are largely unknown. Hexagonal (wurtzite) ZnO crystals terminate with three different types of crystallographic surfaces: charged polar hexagonal (Zn or O), electrically neutral nonpolar rectangular and partially polar pyramidal slanted. In our studies we employ a hydrothermal growth procedure to synthesize nanocrystals and microcrystals of ZnO with tunable morphology to investigate the influence of surface types on interactions with bacteria as well as surface charge dynamics. To quantify the antibacterial action we employ minimum inhibitory concentration (MIC) assays of staphylococcus aureus with hydrothermally-grown ZnO microcrystals. Scanning electron microscopy (SEM) is used to characterize the morphology of the as-grown ZnO specimens as well as the organization of these particles after their interactions with bacteria. To characterize electronic structure and dominant charge transport mechanisms at ZnO surfaces we performed photovoltage (SPV) experiments. Our results confirm that antibacterial action is a result of ZnO surface interactions with extracellular material, whereas internalization of ZnO particles (happening in the case of nanoscale ZnO) is not necessary for inhibition. We also report that the electronic transitions at the surface of the ZnO particles are consistent the theoretically predicted electronic structure of ZnO, with the spectral signatures of surface states which could be the source of the antimicrobial action.

Reportedly, hydrophobic surfaces of polysulfone (PSu) thin films become hydrophilic following exposure to UV radiation and it can affect PSu novel applications in microfluidics and biophysics. Fundamental mechanisms behind this effect remain unknown. To elucidate them, in our work we study surface charge transport employing surface photovoltage (SPV) on thin PSu polysulfone films spin-cast on silicon substrates. Since exposure of PSu even to an ambient UV light could affect the surface properties we ran SPV spectroscopy as well as SPV transient experiments on both as-received samples fabricated in darkness and UV-irradiated films of varying and controllable thicknesses. We report on the comparison of the SPV response in the as-deposited and UV-irradiated polysulfone samples.

Modern astronomical catalogs consist of up to billions of stars and measure various properties of these objects. There have been recent data releases from two of these surveys, GAIA which measures positions and distances, and APOGEE which measures radial velocities and stellar physical properties. By combining these datasets we have the full 6D phase space information for each star and can compute orbital characteristics and kinematics properties. APOGEE targeted specific stellar populations in our Milky Way and determined some of their physical properties. By cross matching with GAIA, we are able to fully describe the orbits of these populations and look for potential new members that have the same physical and kinematic properties but are not located in the immediate vicinity. We will present kinematic properties of the full cross matched dataset as well as information on the targeted stellar populations of the Milky Way.

Metal nanoparticles on a substrate have gained significant attention in recent years as novel systems for new generations of catalysts. Among other metals, iron attracts constant attention due to its low cost. Iron possess either the body-centered cubic (bcc) or the face-centered cubic (fcc) structure. Up to 917 °C, iron exists in its α-form (α-Fe) with the thermodynamically bcc lattice. At 917 °C, α-Fe transforms into the fcc lattice, and this allotrope is termed as γ-iron (γ-Fe) (austenite) with diamagnetic properties. According to the iron-carbon phase diagram, γ-Fe can incorporate up to 2.03% carbon. Lowering the temperature below 917 °C, carbon atoms diffuse out of the structure, and γ-Fe turns back to α-Fe. Up to now, γ-Fe could not be stabilized without such impurities as Mn, Cr, Ni at room temperature. We have obtained of iron nanoparticles with the face-centered cubic structure with diameters of up to 200 nm without impurities on the substrate of graphene oxide by thermal annealing in an inert gas. In our work we show that phases formation of iron depends on the temperature of annealing. At the annealing temperature from 300 ºC through 600 ºC only iron oxides are formed. We established the unexpected formation of the γ-phase already at 700°C by X-Ray diffraction and Mössbauer spectroscopy. These methods clearly identify the stability of the γ-phase at room temperature. The rather low transition temperature of α-Fe to γ-Fe already starting at 700 °C suggests that the mechanism for the transformation is different from that observed for bulk iron. The maximum γ-iron nanoparticles content on the substrate of graphene oxide was fixed at an annealing temperature of 950 °C.

Past research suggests that conditions of scarcity increase the intensity of female same-sex competition. As such, cues to resource scarcity (vs. abundance) might lead women to perceive greater competitive tendencies in their same- (vs. opposite-) sex peers. This prediction was examined across three studies. Across all studies, the opposite pattern of results emerged. Study 1 demonstrated that women perceived higher levels of competitive interactions to occur amongst female (as compared to male and mixed-sex) target groups in environments where resources were abundant. In Study 2, women who perceived resources to be widely available evaluated same-sex others as more competitive than opposite-sex others. Finally, Study 3 provided evidence that women who are led to believe that resources are abundant reported expecting more competitive behavior from their same- (vs. opposite-) sex peers. These results suggest that resource abundance might foster greater competition among women, which has implications for women’s workplace and interpersonal relationships.

Previous research in our lab has found that extrapolating from known to unknown attributes about a group can cause individuals to adopt more extreme attitudes (i.e., become self-radicalized) toward the group. This has been found to be particularly true when people extrapolate from known to unknown attributes about people who agree and disagree with them about a social issue. The current experiment aimed to extend our understanding of these processes by determining whether extrapolating about people who agree and disagree with the extrapolator about a social issue would also report greater self-radicalization toward the social issue in general. Our results revealed that participants who initially opposed kneeling during the national anthem reported more negative attitudes toward kneeling during the national anthem after extrapolating than did participants in the control condition. Conversely, participants who initially favored kneeling during the anthem reported more positive post-manipulation attitudes after extrapolating than did participants in the control condition. These results extend the understanding by which attitudes can become more extreme in the absence of new information.

Few studies have directly evaluated the assumption that equivalence-based instruction (EBI) establishes stimulus classes with greater efficiency than complete instruction (CI) of all possible stimulus relations within each class. The present study was identical to a previous study that failed to support this assumption, except that in the present study, mastery assessment was designed to favor the EBI condition over the CI condition. Forty-eight undergraduate students were assigned to one of four groups that received instruction on arbitrary stimulus relations. The EBI-CI group received EBI in Phase 1 and CI in Phase 2, and vice versa for the CI-EBI group. The EBI-EBI and CI-CI group received EBI and CI in both phases, respectively. In Phase 1, EBI-first groups received training on AB and BC relations and CI-first groups received training with all possible relations. After achieving mastery criterion, the ABC test included all possible trial types. In Phase 2, all groups received training to (a) add a fourth stimulus (D), and (b) add a fifth stimulus (E) to the class, using either EBI or CI. EBI took significantly fewer trials to complete than CI in both phases, but EBI in Phase 1 did not facilitate EBI in Phase 2. The results suggest the EBI arrangement used in this study may be more efficient than CI only because it permits faster learning assessment.

Hypoplastic Left Heart Syndrome
Alexis Damm, PA-S2
A.T. Still University: Arizona School of Health Sciences

Background: Hypoplastic left heart syndrome is a congenital heart disease that involves malformation of the left side of the heart. This etiology requires intervention after birth, and it effects 1 in 4,344 babies born in the United States (CDC, n.d.).

Clinical Case: A 4 year old male diagnosed with hypoplastic left heart syndrome prior to birth. This case study will focus on the history, diagnosis and treatment of a complication of hypoplastic left heart syndrome. The unique factors that influence this patient’s course of treatment will be highlighted in order for the disease to be better understood.

Conclusion: This clinical scenario showcases the importance of understanding birth defects, associated complications, and highlights the positive outcomes of proper pediatric care.

Reference: Center for Disease Control and Prevention. (n.d.). Congenital Heart Defects - Facts about Hypoplastic Left Heart Syndrome | CDC. Retrieved from https://www.cdc.gov/ncbddd/heartdefects/hlhs.html

Recently, terrestrial shoreline spiders have been proposed as biosentinels of bioaccumulative aquatic contaminants such as mercury (Hg). Terrestrial shoreline spiders become contaminated with Hg when they feed on Hg-contaminated emergent aquatic insects. Although the effect of body size on contaminant bioaccumulation in other biosentinels, such as fish, has been thoroughly examined, there has been much less research on the effect of body size on concentrations of Hg in shoreline spiders. In this study, we determined the effect of body size on Hg concentrations in six taxa of shoreline spiders belonging to four families (orb-weavers, [Araneidae], long-jawed orb-weavers, [Tetragnathidae: Tetragnatha spp.], jumping spiders [Salticidae] and wolf spiders [Lycosidae: Pardosa spp., Rabidosa spp. and Schizocosa spp.]. We collected 683 spiders during the day using sweep nets or by hand at night on May 14, June 5, 11, 20 and July 6, 2018 from 14 human-made ponds at the Lyndon B. Johnson National Grasslands, Texas, USA. Average total Hg (THg) concentrations (mean ± SE) ranged from 63 ± 4.0 ng/g to 246 ± 20.1 in Araneidae and Schizocosa spp., respectively, and were significantly different between spider taxa. We measured tibia + patella length on the first leg as a proxy for body size and found that spider THg concentration increased significantly with spider body size for Araneidae, Tetragnatha spp., Salticidae and Pardosa spp. The percent of variation in THg concentration explained by spider body size ranged from 16% to 40% for Pardosa spp. and Salticidae, respectively. This study indicates that Hg accumulation in shoreline spiders differ between spider taxa and within taxa by spider size. We recommend that future studies of Hg in shoreline spiders include assessment of spider size.