Inequities and misaligned expectations in PhD students' search for a research group

Joining a research group is one of the most important events on a graduate student's path to earning a PhD, but the ways students go about searching for a group remain largely unstudied. It is therefore crucial to investigate whether departments are equitably supporting students as they look for an advisor, especially as students today enter graduate school with more diverse backgrounds than ever before. To better understand the phenomenon of finding a research group, we use a comparative case study approach to contrast important aspects of two physics PhD students' experiences. Semi-structured interviews with the students chronicled their interactions with departments, faculty, and the graduate student community, and described the resources they found most and least helpful. Our results reveal significant disparities in students' perceptions of how to find an advisor, as well as inequities in resources that negatively influenced one student's search. We also uncover substantial variation regarding when in their academic careers the students began searching for a graduate advisor, indicating the importance of providing students with consistent advising throughout their undergraduate and graduate experiences.Comment: 5 pages, PERC conference proceedin

VARIANCE AS A FACTOR EFFECT IN INTERDISCIPLINARY STUDIES OF AGRICULTURAL SYSTEMS

Studies of interrelationships among factors typically focus on factor effects related to the mean response. In some instances, response variances, as well as, or even rather than, response means, may be affected by the factors under consideration. In this paper, generalizations of Levene\u27s test and the Jackknife test to two-factor experimental designs are studied via simulation studies to assess their ability to identify differences in the variance as an interaction effect or as a factor main effect. These tests are then applied to a particular example where relationships between chile plants and two prominent pests of chile plants -nematodes and yellow nutsedge -- are under study. This example illustrates the utility of these tests in studying relationships among factors in agricultural systems

Geometric control of myogenic cell fate.

This work combines expertise in stem cell biology and bioengineering to define the system for geometric control of proliferation and differentiation of myogenic progenitor cells. We have created an artificial niche of myogenic progenitor cells, namely, modified extracellular matrix (ECM) substrates with spatially embedded growth or differentiation factors (GF, DF) that predictably direct muscle cell fate in a geometric pattern. Embedded GF and DF signal progenitor cells from specifically defined areas on the ECM successfully competed against culture media for myogenic cell fate determination at a clearly defined boundary. Differentiation of myoblasts into myotubes is induced in growth-promoting medium, myotube formation is delayed in differentiation-promoting medium, and myogenic cells, at different stages of proliferation and differentiation, can be induced to coexist adjacently in identical culture media. This method can be used to identify molecular interactions between cells in different stages of myogenic differentiation, which are likely to be important determinants of tissue repair. The designed ECM niches can be further developed into a vehicle for transplantation of myogenic progenitor cells maintaining their regenerative potential. Additionally, this work may also serve as a general model to engineer synthetic cellular niches to harness the regenerative potential of organ stem cells

Unlocking biomarker discovery: Large scale application of aptamer proteomic technology for early detection of lung cancer

Lung cancer is the leading cause of cancer deaths, because ~84% of cases are diagnosed at an advanced stage. Worldwide in 2008, ~1.5 million people were diagnosed and ~1.3 million died – a survival rate unchanged since 1960. However, patients diagnosed at an early stage and have surgery experience an 86% overall 5-year survival. New diagnostics are therefore needed to identify lung cancer at this stage. Here we present the first large scale clinical use of aptamers to discover blood protein biomarkers in disease with our breakthrough proteomic technology. This multi-center case-control study was conducted in archived samples from 1,326 subjects from four independent studies of non-small cell lung cancer (NSCLC) in long-term tobacco-exposed populations. We measured >800 proteins in 15uL of serum, identified 44 candidate biomarkers, and developed a 12-protein panel that distinguished NSCLC from controls with 91% sensitivity and 84% specificity in a training set and 89% sensitivity and 83% specificity in a blinded, independent verification set. Performance was similar for early and late stage NSCLC. This is a significant advance in proteomics in an area of high clinical need

Biomechanical Evaluation of Recurrent Dissociation of Modular Humeral Prostheses

The purpose of the study was to evaluate the force and torque required to dissociate a humeral head from the unimplanted modular total shoulder replacement system from different manufacturers and to determine if load and torque to dissociation are reduced in the presence of bodily fluids. Impingement, taper contamination, lack of compressive forces, and interference of taper fixation by the proximal humerus have all been reported as possible causes for dissociation. Experimental values determined in this research were compared with literature estimates of dissociation force of the humeral head under various conditions to gain more understanding of the causes of recurrent dissociations of the humeral head. This study examined biomechanical properties under dry and wet conditions under clinically practiced methods. Mean load to dissociation (1513 N ± 508 N) was found to be greater than that exerted by the activities of daily living (578 N) for all implants studied. The mean torque to dissociation was (49.77 N·m ± 19.07 N·m). Analysis of R2 correlation coefficients and p-values (α = 0.05) did not show any significant correlation between dry/bovine, dry/wet, or wet/bovine for load, displacement, or torsional stiffness in the majority of tests performed. Wetting the taper with water or bovine serum did not reduce the dissociation force to a statistically significant degree. Torque and lack of compressive forces at the rotator cuff may be the cause of dissociation at values less than those of activities of daily living. Torque data are provided by this study, but further research is needed to fully appreciate the role of torque in recurrent dissociations

Statistics of Wave Functions in Disordered Systems with Applications to Coulomb Blockade Peak Spacing

Despite considerable work on the energy-level and wavefunction statistics of disordered quantum systems, numerical studies of those statistics relevant for electron-electron interactions in mesoscopic systems have been lacking. We plug this gap by using a tight-binding model to study a wide variety of statistics for the two-dimensional, disordered quantum system in the diffusive regime. Our results are in good agreement with random matrix theory (or its extensions) for simple statistics such as the probability distribution of energy levels or spatial correlation of a wavefunction. However, we see substantial disagreement in several statistics which involve both integrating over space and different energy levels, indicating that disordered systems are more complex than previously thought. These are exactly the quantities relevant to electron-electron interaction effects in quantum dots; in fact, we apply these results to the Coulomb blockade, where we find altered spacings between conductance peaks and wider spin distributions than traditionally expected.Comment: Accepted for publication in Phys Rev

Prospectus, December 11, 1975

LETTERS TO THE EDITOR; IOC: Greetings to campus; Final Exam Schedule; To the Students of Parkland College…; PC News in brief: Christmas Concerts, Chili Supper; Far Out Planet; Anti-football views expressed at meeting; Distaff Side; Skylines; P/C College Theatre plays well recieved; Acupuncture Expert needles P.C. students; Toys for Tots; Vinyl Love; Two compete at Bradley debate; For Santa Claus: Little Jimmy\u27s list; Country Bouquet: Chicano Country; Exotic Dishes tasted by language classes; Rape - $150; Good News; Diana Hill, Scholarship Recipient; The Kaleidoscope; Forum; Reading skills improvement program offered at Parkland; Ike\u27s reply; Mitchell Interview; Prospectus Photo Contest; Christmas Greetings; Classified; Fast Freddy\u27s football forecast; Cobra\u27s Corner; Cobras downed 82-81 in OT; Sports Views; Davidson returns against home team; Henrichs Cut to six in 2nd loss; Lanky Warriors edge Cobrashttps://spark.parkland.edu/prospectus_1975/1000/thumbnail.jp

Changes in Kelp and Other Seaweeds Following Elwha Dam Removal

Kelps are ecologically important seaweeds that dominated the nearshore vegetation community prior to dam removal on the Elwha River. Dam removal is expected to trigger a shift from kelps to vegetation types that are characteristic of soft-sediment communities through restoring natural sediment supply. This study is investigating how nearshore vegetation responds to restoration of the natural sediment regime, both initially when large amounts of sediment entrained in the reservoirs are released and over longer time periods. We assessed vegetation at multiple spatial scales using three approaches. First, we measured floating kelp canopy area using aerial photography. Second, we assessed the abundance of understory kelp and seagrasses with towed videography along 50 km of shoreline. Third, scuba divers recorded density of kelp species and other seaweeds along 10 km of shoreline bracketing the river mouth. Results show profound changes in vegetation and a strong gradient in magnitude of impact related to distance from the river mouth. Floating kelp canopy area decreased 74% in the Elwha Drift Cell in the first year following project initiation (year 1), with lower magnitude losses throughout the Strait of Juan de Fuca. Area of prostrate kelps decreased by 45% (400 ha) and of stipitate kelps by 30% (130 ha) in the Elwha Drift Cell in year 1. Mean kelp density near the river mouth decreased 77% in year 1 and 95% in year 2. While all 10 kelp species declined, annuals were more impacted than perennials. In contrast to the general decline, juveniles of several kelp species appeared in late August of year 2, a substantial delay compared to typical spring timing of juvenile growth. What caused the large kelp losses and apparent delay of juvenile growth? Likely candidates include light reduction from the river plume and scour, burial or settlement inhibition from deposition. These candidates will be explored using physical data from the multidisciplinary research effort