1,000 research outputs found

    Before the Seminoles: Football at Florida State College, 1902-1904

    Get PDF
    When Coach W. W. Hughes looked out at his football team in the autumn of 1902, he was under no pressure to improve on the previous year’s season. Recently hired to teach Latin at Florida State College (FSC), Professor Hughes had played football at Vanderbilt University and, when he arrived in Tallahassee, had volunteered to coach FSC’s fledgling team. Practicing on the newly graded gridiron west of campus (a renovated cow pasture), the FSC Eleven prepared for their first game against a city team from nearby Bainbridge, Georgia. Hughes, pleased with the team’s progress, anticipated success

    Fruit cell culture as a model system to study cell wall changes during strawberry fruit ripening

    Get PDF
    Strawberry (Fragaria x ananassa, Duch.) fruit is characterized by its fast ripening and soft texture at the ripen stage, resulting in a short postharvest shelf life and high economic losses. It is generally believed that the disassembly of cell walls, the dissolution of the middle lamella and the reduction of cell turgor are the main factors determining the softening of fleshy fruits. In strawberry, several studies indicate that the solubilisation and depolymerisation of pectins, as well as the depolymerisation of xyloglucans, are the main processes occurring during ripening. Functional analyses of genes encoding pectinases such as polygalacturonase and pectate lyase also point out to the pectin fraction as a key factor involved in textural changes. All these studies have been performed with whole fruits, a complex organ containing different tissues that differ in their cell wall composition and undergo ripening at different rates. Cell cultures derived from fruits have been proposed as model systems for the study of several processes occurring during fruit ripening, such as the production of anthocyanin and its regulation by plant hormones. The main objective of this research was to obtain and characterize strawberry cell cultures to evaluate their potential use as a model for the study of the cell wall disassembly process associate with fruit ripening. Cell cultures were obtained from cortical tissue of strawberry fruits, cv. Chandler, at the stages of unripe-green, white and mature-red. Additionally, a cell culture line derived from strawberry leaves was obtained. All cultures were maintained in solid medium supplemented with 2.5 mg.l-1 2,4-D and incubated in the dark. Cell walls from the different callus lines were extracted and fractionated to obtain CDTA and sodium carbonate soluble pectin fractions, which represent polyuronides located in the middle lamella or the primary cell wall, respectively. The amounts of homogalacturonan in both fractions were estimated by ELISA using LM19 and LM20 antibodies, specific against demethylated and methyl-esterified homogalacturonan, respectively. In the CDTA fraction, the cell line from ripe fruit showed a significant lower amount of demethylated pectins than the rest of lines. By contrast, the content of methylated pectins was similar in green- and red-fruit lines, and lower than in white-fruit and leaf lines. In the sodium carbonate pectin fraction, the line from red fruit also showed the lowest amount of pectins. These preliminary results indicate that cell cultures obtained from fruits at different developmental stages differ in their cell wall composition and these differences resemble to some extent the changes that occur during strawberry softening. Experiments are in progress to further characterize cell wall extracts with monoclonal antibodies against other cell wall epitopes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Rhamnogalacturonase lyase gene downregulation in strawberry and its potential on mechanical fruit properties

    Get PDF
    Strawberry softening is one of the main factors that reduces fruit quality and leads to economically important losses. Textural changes during fruit ripening are mainly due to the dissolution of middle lamellae, a reduction in cell-to-cell adhesion and the weakening of parenchyma cell walls as a result of the action of cell wall modifying enzymes. Functional studies of genes encoding pectinase enzymes (polygalacturonase, pectate lyase and -galactosidase) support a key role of pectin disassembly in strawberry softening. Evidence that RG-I may play an important role in strawberry texture has been obtained from the transient silencing of a RG-lyase gene. Pectins are major components of fruit cell walls and highly dynamic polysaccharides, but due to their heterogeneity the precise relation between the structures and functions is incomplete. In this work, stable transgenic strawberry lines with a rhamnogalacturonate lyase gene (FaRGLyase1) down-regulated have been analyzed. Several transgenic lines showing more than 95% silencing of FaRGLyase1 displayed fruit firmness values higher than control. Cell walls from these lines were extracted and analyzed by ELISA and Epitope Detection Chromatography (EDC). This last technique is based on the detection of specific cell wall oligosaccharide epitopes and provides information on sub-populations of pectins containing homogalacturonan and RG-I domains, but also reveals potential links with other cell wall polysaccharides such as xyloglucan. The results obtained indicate that the silencing of FaRGLyase1 reduces degradation of RG-I backbones, but also homogalacturonan, in cell walls, especially in pectin fractions covalently bound to the cell wall. These changes contribute to the increased firmness of transgenic fruits.This research was supported by FEDER EU Funds and the Ministerio de Economía y Competitividad of Spain (grant reference AGL2014-55784-C2), a Marie Curie IEF within the 7th European Community Framework Programme (reference: PIEF-2013-625270) for SP and a FPI fellowship (BES-2015-073616) to support PR-V. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Modeling SIGINT

    Get PDF
    NPS NRP Executive SummaryOPNAV and NAVAIR seek to more accurately assess both the engineering-level capability of a set of airborne SIGINT sensors against a representative set of threat emissions, and the impact of those airborne SIGINT sensors on effects chains. Intent is to assess current and future performance, better informing investment and design trade space decisions. The research objectives are threefold: survey existing SIGINT Modeling capabilities within the DOD, design and implement engineering level SIGINT modeling capabilities as required, and finally, match/aggregate those engineering level results to mission level models such as the Naval Simulation System (NSS) and the Advanced Framework for Simulation, Integration, and Modeling (AFSIM). The research approach will be straight forward. All researchers will collaborate on surveying the existing SIGINT modeling domain. Then the research team will create two sub teams. The first will investigate possible SIGINT Engineering modeling solutions. The second team will investigate the requirements for feeding SIGINT engineering details into the mission models. Deliverables are intended to be a completed survey of SIGINT Modeling, with an analysis of possible capability gaps, design and or production of engineering level SIGINT Models, and instructions for how to aggregate SIGINT engineering models into mission level models.N9 - Warfare SystemsThis research is supported by funding from the Naval Postgraduate School, Naval Research Program (PE 0605853N/2098). https://nps.edu/nrpChief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.

    Modeling SIGINT

    Get PDF
    NPS NRP Project PosterOPNAV and NAVAIR seek to more accurately assess both the engineering-level capability of a set of airborne SIGINT sensors against a representative set of threat emissions, and the impact of those airborne SIGINT sensors on effects chains. Intent is to assess current and future performance, better informing investment and design trade space decisions. The research objectives are threefold: survey existing SIGINT Modeling capabilities within the DOD, design and implement engineering level SIGINT modeling capabilities as required, and finally, match/aggregate those engineering level results to mission level models such as the Naval Simulation System (NSS) and the Advanced Framework for Simulation, Integration, and Modeling (AFSIM). The research approach will be straight forward. All researchers will collaborate on surveying the existing SIGINT modeling domain. Then the research team will create two sub teams. The first will investigate possible SIGINT Engineering modeling solutions. The second team will investigate the requirements for feeding SIGINT engineering details into the mission models. Deliverables are intended to be a completed survey of SIGINT Modeling, with an analysis of possible capability gaps, design and or production of engineering level SIGINT Models, and instructions for how to aggregate SIGINT engineering models into mission level models.N9 - Warfare SystemsThis research is supported by funding from the Naval Postgraduate School, Naval Research Program (PE 0605853N/2098). https://nps.edu/nrpChief of Naval Operations (CNO)Approved for public release. Distribution is unlimited.

    Specific heat of MgB_2 after irradiation

    Full text link
    We studied the effect of disorder on the superconducting properties of polycrystalline MgB_2 by specific-heat measurements. In the pristine state, these measurements give a bulk confirmation of the presence of two superconducting gaps with 2 Delta 0 / k_B T_c = 1.3 and 3.9 with nearly equal weights. The scattering introduced by irradiation suppresses T_c and tends to average the two gaps although less than predicted by theory. We also found that by a suitable irradiation process by fast neutrons, a substantial bulk increase of dH_{c2}/dT at T_c can be obtained without sacrificing more than a few degrees in T_c. The upper critical field of the sample after irradiation exceeds 28 T at T goes to 0 K.Comment: 11 pages text, 6 figures, accepted by Journal of Physics: Condensed Matte

    Trapping of a random walk by diffusing traps

    Full text link
    We present a systematic analytical approach to the trapping of a random walk by a finite density rho of diffusing traps in arbitrary dimension d. We confirm the phenomenologically predicted e^{-c_d rho t^{d/2}} time decay of the survival probability, and compute the dimension dependent constant c_d to leading order within an eps=2-d expansion.Comment: 16 pages, to appear in J. Phys.
    • …
    corecore