Studying the Behavioral Role of the KCNN2 Gene in Zebrafish Embryos

Introduction: Mutations in the KCNN2 gene have been linked to phenotypes of movement disorders and autism. The goal of this experiment was to use the CIUSPR-Cas9 system to create a deletion within the KCNN2 gene and to observe the effect on the expression of movement in zebra fish embryos. Methods: Linearized Cas9 DNA and guide DNA underwent in vitm transcription (IVT) reactions to produce RNA to be injected into zebrafish embryos at the one cell stage. KCNN guide RNAs were produced for the KCNN2 and KCNN3 genes (to prevent KCNN3 protein function from compensating for loss ofKCNN2\u27s protein function), and the SLC45A2 gene, which was used as a positive control to indicate success of reagent preparation and Cas9 function. Genorypic and phenotypic analyses were performed 2 days post-fertilization (dpf). Results: No notable difference was seen with genotypic analysis, but KCNN-injected embryos moved less in unprovoked and provoked phenotypic movement tests than wild type (WT) embryos. Discussion: Microdeletions may have been the cause of the observed phenotypic difference between KCNN-injected and WT embryos, however, statistical analysis showed that the observed differences in quantity of movement were not statistically significant. Conclusion: The data collected in this experiment is not sufficient to conclude whether or not microdeletions in the KCNN2 gene were produced or may have co11tributed to a difference in the expression of movement in zebrafish embryos. Future research should be conducted targeting different guide sequences and using more sophisticated genotypic and phenotypic analyses

Ground control system for the midcourse space experiment UTC clock

One goal of the Midcourse Space Experiment (MSX) spacecraft Operations Planning Center is to maintain the onboard satellite UTC clock (UTC(MSX)) to within 1 millisecond of UTC(APL) (the program requirement is 10 msec). The UTC(MSX) clock employs as its time base an APL built 5 MHz quartz oscillator, which is expected to have frequency instabilities (aging rate + drift rate + frequency offset) that will cause the clock to drift approximately two to ten milliseconds per day. The UTC(MSX) clock can be advanced or retarded by the APL MSX satellite ground control center by integer multiples of 1 millisecond. The MSX Operations Planning Center is developing software which records the drift of UTC(MSX) relative to UTC(APL) and which schedules the time of day and magnitude of UTC(MSX) clock updates up to 48 hours in advance. Because of the manner in which MSX spacecraft activities are scheduled, MSX clock updates are planned 24 to 48 hours in advance, and stored in the satellite's computer controller for later execution. Data will be collected on the drift of UTC(MSX) relative to UTC(APL) over a three to five day period. Approximately six times per day, the time offset between UTC(MSX) and UTC(APL) will be measured by APL with a resolution of less than 100 microseconds. From this data a second order analytical model of the clock's drift will be derived. This model will be used to extrapolate the offset of the MSX clock in time from the present to 48 hours in the future. MSX clock updates will be placed on the spacecraft's daily schedule whenever the predicted clock offset exceeds 0.5 milliseconds. The paper includes a discussion of how the empirical model of the MSX clock is derived from satellite telemetry data, as well as the algorithm used to schedule MSX clock updates based on the model

Somalia, the New Barbary? Piracy and Islam in the Horn of Africa,

Within the sea services, allusion to the Barbary pirates and the “shores of Trip- oli” continues to resonate. Readers of Martin Murphy’s detailed and thought- ful book Somalia may come away wish- ing that a solution to the situation our mariners and fleet forces now face in those inhospitable waters were as straightforward as storming the beaches

Measurements of acoustic scattering from zooplankton and oceanic microstructure using a broadband echosounder

© 2009 The Authors. This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License. The definitive version was published in ICES Journal of Marine Science: Journal du Conseil 67 (2010): 379-394, doi:10.1093/icesjms/fsp242.In principle, measurements of high-frequency acoustic scattering from oceanic microstructure and zooplankton across a broad range of frequencies can reduce the ambiguities typically associated with the interpretation of acoustic scattering at a single frequency or a limited number of discrete narrowband frequencies. With this motivation, a high-frequency broadband scattering system has been developed for investigating zooplankton and microstructure, involving custom modifications of a commercially available system, with almost complete acoustic coverage spanning the frequency range 150–600 kHz. This frequency range spans the Rayleigh-to-geometric scattering transition for some zooplankton, as well as the diffusive roll-off in the spectrum for scattering from turbulent temperature microstructure. The system has been used to measure scattering from zooplankton and microstructure in regions of non-linear internal waves. The broadband capabilities of the system provide a continuous frequency response of the scattering over a wide frequency band, and improved range resolution and signal-to-noise ratios through pulse-compression signal-processing techniques. System specifications and calibration procedures are outlined and the system performance is assessed. The results point to the utility of high-frequency broadband scattering techniques in the detection, classification, and under certain circumstances, quantification of zooplankton and microstructure.The work was supported by the US Office of Naval Research (Grant # N000140210359)