Microbial communities in dark oligotrophic volcanic ice cave ecosystems of Mt. Erebus, Antarctica.

The Earth's crust hosts a subsurface, dark, and oligotrophic biosphere that is poorly understood in terms of the energy supporting its biomass production and impact on food webs at the Earth's surface. Dark oligotrophic volcanic ecosystems (DOVEs) are good environments for investigations of life in the absence of sunlight as they are poor in organics, rich in chemical reactants and well known for chemical exchange with Earth's surface systems. Ice caves near the summit of Mt. Erebus (Antarctica) offer DOVEs in a polar alpine environment that is starved in organics and with oxygenated hydrothermal circulation in highly reducing host rock. We surveyed the microbial communities using PCR, cloning, sequencing and analysis of the small subunit (16S) ribosomal and Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (RubisCO) genes in sediment samples from three different caves, two that are completely dark and one that receives snow-filtered sunlight seasonally. The microbial communities in all three caves are composed primarily of Bacteria and fungi; Archaea were not detected. The bacterial communities from these ice caves display low phylogenetic diversity, but with a remarkable diversity of RubisCO genes including new deeply branching Form I clades, implicating the Calvin-Benson-Bassham (CBB) cycle as a pathway of CO2 fixation. The microbial communities in one of the dark caves, Warren Cave, which has a remarkably low phylogenetic diversity, were analyzed in more detail to gain a possible perspective on the energetic basis of the microbial ecosystem in the cave. Atmospheric carbon (CO2 and CO), including from volcanic emissions, likely supplies carbon and/or some of the energy requirements of chemoautotrophic microbial communities in Warren Cave and probably other Mt. Erebus ice caves. Our work casts a first glimpse at Mt. Erebus ice caves as natural laboratories for exploring carbon, energy and nutrient sources in the subsurface biosphere and the nutritional limits on life

Letters from Olive Fremstad to Willa Cather: A View Beyond \u3ci\u3eThe Song of the Lark\u3c/i\u3e

In 1913, Willa Cather met opera-diva Olive Fremstad and the two formed a friendship that would span at least a decade. Fremstad has long been recognized as an inspiration for the character Thea Kronborg of Cather’s Song of the Lark (1915) but has not been portrayed as influential in any other aspects to Cather’s career. Letters sent by Fremstad to Cather have recently been located, and they reveal an ongoing and interdisciplinary dialogue between the two women that negotiates issues surrounding art and professionalism. I locate these letters within the broader context of Cather’s public and fictional statements about art during this period and find evidence of Fremstad’s influence, particularly in the concept of performative selves as an integral part of the artist’s identity and praxis. Furthermore, this relationship challenges the pervasive mythos of Cather as an isolated artist torn between considerations of commercialism and high art. By considering Cather’s relationship with Fremstad and its ensuing dialogue, I have found that Cather began her career as a professional novelist fully aware and capable of reconciling the supposed tension between her art, personal life, and commercial acumen. Cather wrote the opera stories collected in Youth and the Bright Medusa (1920) throughout this period and reveal her development of an ideology engaged with feminine vitality as a means for producing art. Advisor: Melissa J. Homestea

Pin Router Duplicator Base

The idea for the following project came from the Lean Manufacturing class that is offered at Central Washington University. In this class the manufacturing processes is demonstrated through the production of guitar kits. A problem with the class is that the CNC machine gets backed up causing a bottleneck in the production line. The solution to this problem was to make a pin router duplicator. A pin router duplicator is a device that allows the operator to trace a finished part with a pin while a router mimics its movements, cutting a new part. The component that is looked into for this report is the base. The base allows for movement in the x and y-axis and the ability to hold the head unit. The main requirement for this project were limiting the amount of deflection in the shafts to maintain a part tolerances of 5 thousandths and a repeatability of 2 thousandths. To achieve these requirements, linear bearings and precision shafting were to be used. However, due to cost restraints, a prototype design had to be substituted. The design ended up going to smaller diameter shafts with a rougher surface finish, and substituted bearings for plastic sliders. This changed the testing to be comparing a calculated amount of deflection, to an actual measured amount of deflection on a shaft. Through this testing, it could be seen that the device would function the way that was predicted and actually deflected a little less then expected

Ferromanganese nodules and micro-hardgrounds associated with the Cadiz Contourite Channel (NE Atlantic): Palaeoenvironmental records of fluid venting and bottom currents

Ferromanganese nodule fields and hardgrounds have recently been discovered in the Cadiz Contourite Channel in the Gulf of Cadiz (850–1000 m). This channel is part of a large contourite depositional system generated by the Mediterranean Outflow Water. Ferromanganese deposits linked to contourites are interesting tools for palaeoenviromental studies and show an increasing economic interest as potential mineral resources for base and strategic metals. We present a complete characterisation of these deposits based on submarine photographs and geophysical, petrographic, mineralogical and geochemical data. The genesis and growth of ferromanganese deposits, strongly enriched in Fe vs. Mn (av. 39% vs. 6%) in this contourite depositional system result from the combination of hydrogenetic and diagenetic processes. The interaction of the Mediterranean Outflow Water with the continental margin has led to the formation of Late Pleistocene–Holocene ferromanganese mineral deposits, in parallel to the evolution of the contourite depositional system triggered by climatic and tectonic events. The diagenetic growth was fuelled by the anaerobic oxidation of thermogenic hydrocarbons (δ13CPDB=−20 to −37‰) and organic matter within the channel floor sediments, promoting the formation of Fe–Mn carbonate nodules. High 87Sr/86Sr isotopic values (up to 0.70993±0.00025) observed in the inner parts of nodules are related to the influence of radiogenic fluids fuelled by deep-seated fluid venting across the fault systems in the diapirs below the Cadiz Contourite Channel. Erosive action of the Mediterranean Outflow Water undercurrent could have exhumed the Fe–Mn carbonate nodules, especially in the glacial periods, when the lower core of the undercurrent was more active in the study area. The growth rate determined by 230Thexcess/232Th was 113±11 mm/Ma, supporting the hypothesis that the growth of the nodules records palaeoenvironmental changes during the last 70 ka. Ca-rich layers in the nodules could point to the interaction between the Mediterranean Outflow Water and the North Atlantic Deep Water during the Heinrich events. Siderite–rhodochrosite nodules exposed to the oxidising seabottom waters were replaced by Fe–Mn oxyhydroxides. Slow hydrogenetic growth of goethite from the seawaters is observed in the outermost parts of the exhumed nodules and hardgrounds, which show imprints of the Mediterranean Outflow Water with low 87Sr/86Sr isotopic values (down to 0.70693±0.00081). We propose a new genetic and evolutionary model for ferromanganese oxide nodules derived from ferromanganese carbonate nodules formed on continental margins above the carbonate compensation depth and dominated by hydrocarbon seepage structures and strong erosive action of bottom currents. We also compare and discuss the generation of ferromanganese deposits in the Cadiz Contourite Channel with that in other locations and suggest that our model can be applied to ferromanganiferous deposits in other contouritic systems affected by fluid venting

Gender Difference in Perception of Masculine and Feminine Gender Roles among Primary Schools Children

The purpose of this study was to investigate whether there is statistically significant gender difference in perception of masculine and feminine gender roles. Data were collected from 156 randomly selected respondents from Burayu Primary and Lalisies Talent Schools Oromia regional state Ethiopia. The reliability and face validity questionnaire was checked via pilot test. The results revealed that a substantial sex difference in perception of gender roles. That means females are socialized to be more feminine than males are. However, both sexes did not differ significantly with respect to perception of masculine gender role. Implications of the results for practice and future research are discussed. Keywords: Burayu, Children, Gender role perception, Primary School

De Novo Designed Metallopeptides to Investigate Metal Ion Homeostasis, Electron Transfer, and Redox Catalysis.

Protein design is a powerful way to interrogate the basic requirements for function of metal sites by systematically incorporating elements important for function. Single-stranded three-helix bundles with either thiolate-rich sites for spectroscopic characterization and electron transfer, or histidine-rich sites for redox catalysis are described. Using a previous design, two constructs were designed to incorporate a fourth cysteine residue to investigate thiolate-rich sites involved in metal ion homeostasis and electron transfer. Rational re-design replaced a putative coordinating histidine with a cysteine. A second construct embedded a CXXC binding motif into the helical scaffold. These two constructs show different UV-visisble, 113Cd NMR, and 111mCd PAC, which indicate that they form different proportions of CdS3O and CdS4. The spectroscopy of these sites sheds light on how Cd(II) bindis to CadC and suggests a dynamic site in fast exchange with the solvent. Previous attempts at the design of a rubredoxin site have focused on reproducing the peptide fold around or using flexible loop regions to define the site in addition to canonical CXXC motifs. However, the use of CXXC motifs embedded in an α-helical scaffold produces a rubredoxin site that reproduces the Mössbauer, MCD, and EPR of rubredoxin without the use of loop regions. This successful design is the largest deviation from consensus rubredoxin and zinc finger folds reported. Electron transfer rates through a de novo designed scaffold were studied by the design and synthesis of a ruthenium trisbipyridine derivative appended to an exterior cysteine residues. A redox-active tyrosine in the 70th position is implicated as a relay amino acid from the iron center and absence of the tyrosine decreases the rate of electron transfer from the metal site. This is the first photo-generated tyrosine radical in a designed protein. A construct, which was previously reported for CO2 hydration, is substituted with copper and its spectroscopic and nitrite reductase activity are studied. This is the first demonstration of nitrite reductase activity in a single-stranded designed peptide. This thesis provides insight into designed proteins and their applications and lays the groundwork for further studies to progress towards a unified multifunctional redox protein.PHDChemical BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113513/1/agtebo_1.pd