Looking On and Overlooking: An Analysis of Oversight in Online Tutoring

As a writing center director, I am charged with overseeing my staff of undergraduate tutors, as well as making sure the center functions in accordance with its budget and mission. All of my duties–training tutors, scheduling, working with faculty, performing public relations, guiding tutors’ ongoing professional development–can be viewed as forms of oversight. I find the term “oversight” to be a very apt lens for considering the work of a writing center director because of its dual meaning: it can mean “looking over,” “supervising”–or it can suggest the opposite, as in “overlooking” or “forgetfulness, missing.”University Writing Cente

A universal solution

The phenomenon of an implicit function which solves a large set of second order partial differential equations obtainable from a variational principle is explicated by the introduction of a class of universal solutions to the equations derivable from an arbitrary Lagrangian which is homogeneous of weight one in the field derivatives. This result is extended to many fields. The imposition of Lorentz invariance makes such Lagrangians unique, and equivalent to the Companion Lagrangians introduced in [baker].Comment: arxiv version is already officia

Readout system for radiation detector

Improved electrical circuit determines the amount of light detected by a photomultiplier tube when its output signal is in the dark-current range of the tube. The low-intensity light to which the tube responds arises from a thermo-luminescent ionized dosimeter

Real-time ISEE data system

A real-time ISEE data system directed toward predicting geomagnetic substorms and storms is discussed. Such a system may allow up to 60+ minutes advance warning of magnetospheric substorms and up to 30 minute warnings of geomagnetic storms (and other disturbances) induced by high-speed streams and solar flares. The proposed system utilizes existing capabilities of several agencies (NASA, NOAA, USAF), and thereby minimizes costs. This same concept may be applicable to data from other spacecraft, and other NASA centers; thus, each individual experimenter can receive quick-look data in real time at his or her base institution

Petrography and petrology of the Hawaii Scientific Drilling Project lavas: Inferences from olivine phenocryst abundances and compositions

The Mauna Loa (ML) and Mauna Kea (MK) lavas recovered by the Hawaii Scientific Drilling Project (HSDP) include aphyric to highly olivine-phyric basalts. The average olivine phenocryst abundance in the reference suite of ML flows is 14.5 vol % (vesicle-free and weighted by the flow thickness), while the average abundances of olivine in the reference suites of the MK alkalic and tholeiitic basalts are 1.1 and 14.0 vol %, respectively. Plagioclase and augite phenocrysts are rare in the ML and MK tholeiites, but the MK alkalic basalts can have up to 4 vol % plagioclase phenocrysts. Strained olivine grains, thought to represent disaggregated dunite xenoliths from the cumulate pile within the magma chamber(s), are ubiquitous in the drill core lavas. These deformed grains can comprise up to 50 % of the modal olivine in a given rock. Olivine core compositions in the lavas span forsterite contents of 80.4–90.7 (median 88.8, ML tholeiites), 75.8–86.6 (median 85.8, MK alkalic basalts), and 76.3–90.5 (median 88.0 mol %, MK tholeiites). Olivines with core compositions in the range Fo_(89–90.5) are present in tholeiitic lavas with a wide range of whole-rock MgO contents (9–30 wt %). Strained and unstrained olivines completely overlap in composition as do the compositions of spinels (100*Cr/(Cr+Al) ∼59–72; Mg# = 100*Mg/(Mg+Fe^(2+)) ∼40–66) present as inclusions in the olivine phenocrysts. The presence of Fo_(90.5) olivine in the HSDP lavas requires magmas with ∼16 wt % MgO in the ML and MK plumbing systems. Rare dunite xenoliths are also present in the drill core lavas. While compositionally homogeneous within a given xenolith, the six xenoliths contain olivines that span a wide range of forsterite contents (78.3–89.2 mol %). Spinels in these xenoliths are chrome-rich, have Mg# between 31 and 66, and define two populations on the basis of TiO_2 contents. Whole-rock compositions for the ML and MK tholeiites define olivine control lines on MgO-oxide diagrams, and the relationship between whole-rock MgO and olivine phenocryst abundance in these lavas suggests that the lavas with >12 wt % MgO have accumulated olivine. Comparing the weighted bulk composition of all of the MK tholeiites in the drill core with a calculated parental magma suggests that, on average, the MK tholeiites entrained most of the olivine phenocrysts that crystallized from their parental liquids. Although deformed olivines in Hawaiian lavas are widely thought to represent disaggregated dunite xenoliths, none of the majoror minor-element data on the strained or unstrained olivine phenocrysts suggest that the strained olivines in the HSDP lavas are exotic. We suggest that most of the olivine phenocrysts in a given flow, whether strained or unstrained, are closely related to the evolved liquid that now forms the groundmass. This is consistent with observed correlations between isotopic systems measured on olivine separates (e.g., O, He) and isotopic systems dominated by groundmass (e.g., Nd, Pb)