An Engineering Learning Community To Promote Retention And Graduation Of At-Risk Engineering Students

Retention and graduation rates for engineering disciplines are significantly lower than desired, and research literature offers many possible causes. Engineering learning communities provide the opportunity to study relationships among specific causes and to develop and evaluate activities designed to lessen their impact. This paper details an engineering learning community created to combat three common threats to academic success of engineering students: financial difficulties, math deficiencies, and the lack of a supportive engineering culture. The project tracks participants in the learning community from first year through graduation to assess the effectiveness of its activities in improving retention and graduation rates. Scholarships were made available to address the financial difficulties; tutors, mentors, study groups, and a “freshman-to-sophomore bridge” summer program were provided to address math deficiencies; cohort engineering courses, active learning techniques, required group meetings, required group study sessions, dedicated study space, and dedicated faculty advisors were used to promote a sense of community. Quantitative retention and graduation rates for the cohort are compared to other engineering groups at the same institution. Qualitative results collected via student surveys and interviews, and lessons learned by project administrators are also presented. Retention and graduation rates of the cohort are better than those of comparable groups at the same institution. Graduation rates based upon freshman math placement are also higher than comparable groups.

Mechanism of Magainin 2a Induced Permeabilization of Phospholipid Vesicles

The magainins, peptide antibiotics secreted by the frog Xenopus laevis, have previously been shown to permeabilize phospholipid vesicles. To elucidate the mechanism of permeabilization, we have conducted detailed kinetic studies of magainin 2 amide (mgn2a)hduced release of 6-carboxyfluorescein from vesicles of phosphatidylserine. The results show that dye release occurs in (at least) two stages-an initial rapid phase, with t1/2 ≈ 3 s, followed by a much slower phase that approaches zero leakage rate before all the dye is released. Light-scattering studies showed that mgn2a does not cause gross changes in vesicle structure. The peptide was found to rapidly equilibrate between vesicles; this was demonstrated by determining a binding isotherm for the peptidelipid interaction, and by showing that addition of unloaded vesicles rapidly quenches peptide-induced leakage from loaded vesicles. Transient dye release in the presence of an equilibrating peptide can be explained in two ways: (1) the peptide exists only transiently in an active form; (2) the vesicles are only transiently leaky. Preincubation of mgn2a at assay concentrations in buffer alone or with unloaded vesicles did not inactivate the peptide. Therefore, rapid leakage is probably due to transient destabilization of the vesicle upon addition of mgn2a

Mechanism of Magainin 2a Induced Permeabilization of Phospholipid Vesicles

The magainins, peptide antibiotics secreted by the frog Xenopus laevis, have previously been shown to permeabilize phospholipid vesicles. To elucidate the mechanism of permeabilization, we have conducted detailed kinetic studies of magainin 2 amide (mgn2a)hduced release of 6-carboxyfluorescein from vesicles of phosphatidylserine. The results show that dye release occurs in (at least) two stages-an initial rapid phase, with t1/2 ≈ 3 s, followed by a much slower phase that approaches zero leakage rate before all the dye is released. Light-scattering studies showed that mgn2a does not cause gross changes in vesicle structure. The peptide was found to rapidly equilibrate between vesicles; this was demonstrated by determining a binding isotherm for the peptidelipid interaction, and by showing that addition of unloaded vesicles rapidly quenches peptide-induced leakage from loaded vesicles. Transient dye release in the presence of an equilibrating peptide can be explained in two ways: (1) the peptide exists only transiently in an active form; (2) the vesicles are only transiently leaky. Preincubation of mgn2a at assay concentrations in buffer alone or with unloaded vesicles did not inactivate the peptide. Therefore, rapid leakage is probably due to transient destabilization of the vesicle upon addition of mgn2a

Raman Spectroscopy of Synthetic Antimicrobial Frog Peptides Magainin 2a and PGLa

Magainin and PGLa are 23- and 21-residue peptides isolated from the skin of the African clawed frog Xenopus lueuis. They protect the frog from infection and exhibit a broad-spectrum antimicrobial activity in vitro. The mechanism of this activity involves the interaction of magainin with microbial membranes. We have measured the secondary structure and membrane-perturbing ability of these peptides to obtain information about this mechanism. Our results show that mgn2a forms a helix with an average length of less than 20 Å upon binding to liposomes. At high concentrations (50 mg/mL) mgn2a spontaneously solubilizes phosphatidylcholine liposomes at temperatures above the gel-liquid-crystalline phase transition. Mgn2a appears to bind to the surface of liposomes made of negatively charged lipids without spontaneously penetrating the bilayer. Finally, mgn2a and PGLa interact together with liposomes in a synergistic way that enhances the helix content of one or both of the peptides and allows the peptides to more easily penetrate the bilayer. PGLa mixed with a small nonperturbing amount of magainin 2 amide is 25-43 times as potent as PGLa alone at inducing the release of carboxyfluorescein from liposomes. The results suggest that the mechanism of antimicrobial activity does not involve a channel formed by transmembrane helical peptides

Leaders Assess the Current State of the Academic IS Discipline

Telephone interviews were conducted with 17 leaders in the IS academic field. The leaders shared their views on the current status of the IS field in terms of the strengths, weaknesses, opportunities, and threats facing the discipline. The insights of the leaders are organized into 10 categories, including the core identity of IS, the legitimacy of the IS field, competitors to what we teach and research, research rigor versus relevance, the pervasiveness of information technology, the impacts of changing technology, the quantity and quality of journals, the demand for IS services, and ICIS and AIS. In many areas the leaders agree on the issues. Most of the differences of opinion are research related, such as the core identity of the field for research purposes, how to best achieve relevance in our research, and the number of journals in our field

Remotely Accessible Testbed for Software Defined Radio Development

Previous development testbeds have assumed that the developer was physically present in front of the hardware being used. No provision for remote operation of basic functions (power on/off or reset) was made, because the developer/operator was sitting in front of the hardware, and could just push the button manually. In this innovation, a completely remotely accessible testbed has been created, with all diagnostic equipment and tools set up for remote access, and using standardized interfaces so that failed equipment can be quickly replaced. In this testbed, over 95% of the operating hours were used for testing without the developer being physically present. The testbed includes a pair of personal computers, one running Linux and one running Windows. A variety of peripherals is connected via Ethernet and USB (universal serial bus) interfaces. A private internal Ethernet is used to connect to test instruments and other devices, so that the sole connection to the outside world is via the two PCs. An important design consideration was that all of the instruments and interfaces used stable, long-lived industry standards, such as Ethernet, USB, and GPIB (general purpose interface bus). There are no plug-in cards for the two PCs, so there are no problems with finding replacement computers with matching interfaces, device drivers, and installation. The only thing unique to the two PCs is the locally developed software, which is not specific to computer or operating system version. If a device (including one of the computers) were to fail or become unavailable (e.g., a test instrument needed to be recalibrated), replacing it is a straightforward process with a standard, off-the-shelf device

S-Band POSIX Device Drivers for RTEMS

This is a set of POSIX device driver level abstractions in the RTEMS RTOS (Real-Time Executive for Multiprocessor Systems real-time operating system) to SBand radio hardware devices that have been instantiated in an FPGA (field-programmable gate array). These include A/D (analog-to-digital) sample capture, D/A (digital-to-analog) sample playback, PLL (phase-locked-loop) tuning, and PWM (pulse-width-modulation)-controlled gain. This software interfaces to Sband radio hardware in an attached Xilinx Virtex-2 FPGA. It uses plug-and-play device discovery to map memory to device IDs. Instead of interacting with hardware devices directly, using direct-memory mapped access at the application level, this driver provides an application programming interface (API) offering that easily uses standard POSIX function calls. This simplifies application programming, enables portability, and offers an additional level of protection to the hardware. There are three separate device drivers included in this package: sband_device (ADC capture and DAC playback), pll_device (RF front end PLL tuning), and pwm_device (RF front end AGC control)

XO-5b: A Transiting Jupiter-sized Planet With A Four Day Period

The star XO-5 (GSC 02959-00729, V=12.1, G8V) hosts a Jupiter-sized, Rp=1.15+/-0.12 Rjup, transiting extrasolar planet, XO-5b, with an orbital period of P=4.187732+/-0.00002 days. The planet mass (Mp=1.15+/-0.08 Mjup) and surface gravity (gp=22+/-5 m/s^2) are significantly larger than expected by empirical Mp-P and Mp-P-[Fe/H] relationships. However, the deviation from the Mp-P relationship for XO-5b is not large enough to suggest a distinct type of planet as is suggested for GJ 436b, HAT-P-2b, and XO-3b. By coincidence XO-5 overlies the extreme H I plume that emanates from the interacting galaxy pair NGC 2444/NGC 2445 (Arp 143).Comment: 10 pages, 9 Figures, Submitted to Ap