Florida State University

About: Florida State University is a education organization based out in Tallahassee, Florida, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 25117 authors who have published 65361 publications receiving 2527087 citations. The organization is also known as: FSU & Florida State.

Coordinated Control of Distributed Energy Storage System With Tap Changer Transformers for Voltage Rise Mitigation Under High Photovoltaic Penetration

Abstract: This paper proposes a coordinated control of distributed energy storage system (ESS) with traditional voltage regulators including the on-load tap changer transformers (OLTC) and step voltage regulators (SVR) to solve the voltage rise problem caused by the high photovoltaic (PV) penetration in the low-voltage distribution network. The main objective of this coordinated control is to relieve the tap changer transformer operation stress, shave the distribution network peak load and decrease the transmission and distribution resistive power losses under high solar power penetration. The proposed control method limits the energy storage depth of discharge in order to meet a more than ten-year cycle life. A benchmark distribution network model was developed in the Real Time Digital Simulator (RTDS) and the simulation results from the studied cases verified the proposed coordinated control strategy. The experimental implementation of proposed control algorithms were developed based on a power hardware-in-the-loop (PHIL) test bed with a 22 kWh ESS, a smart meter, Labview controller, and RTDS. The experimental results were consistent with those obtained from simulation study.

Protein-only transmission of three yeast prion strains

Abstract: Key questions regarding the molecular nature of prions are how different prion strains can be propagated by the same protein and whether they are only protein1,2,3. Here we demonstrate the protein-only nature of prion strains in a yeast model, the [PSI] genetic element that enhances the read-through of nonsense mutations in the yeast Saccharomyces cerevisiae4,5. Infectious fibrous aggregates containing a Sup35 prion-determining amino-terminal fragment labelled with green fluorescent protein were purified from yeast harbouring distinctive prion strains. Using the infectious aggregates as ‘seeds’, elongated fibres were generated in vitro from the bacterially expressed labelled prion protein. De novo generation of strain-specific [PSI] infectivity was demonstrated by introducing sheared fibres into uninfected yeast hosts. The cross-sectional morphology of the elongated fibres generated in vitro was indistinguishable from that of the short yeast seeds, as visualized by electron microscopy. Electron diffraction of the long fibres showed the 4.7 A spacing characteristic of the cross-beta structure of amyloids. The fact that the amyloid fibres nucleated in vitro propagate the strain-specific infectivity of the yeast seeds implies that the heritable information of distinct prion strains must be encoded by different, self-propagating cross-beta folding patterns of the same prion protein.

Global patterns of kelp forest change over the past half-century

Abstract: Kelp forests (Order Laminariales) form key biogenic habitats in coastal regions of temperate and Arctic seas worldwide, providing ecosystem services valued in the range of billions of dollars annually. Although local evidence suggests that kelp forests are increasingly threatened by a variety of stressors, no comprehensive global analysis of change in kelp abundances currently exists. Here, we build and analyze a global database of kelp time series spanning the past half-century to assess regional and global trends in kelp abundances. We detected a high degree of geographic variation in trends, with regional variability in the direction and magnitude of change far exceeding a small global average decline (instantaneous rate of change = −0.018 y−1). Our analysis identified declines in 38% of ecoregions for which there are data (−0.015 to −0.18 y−1), increases in 27% of ecoregions (0.015 to 0.11 y−1), and no detectable change in 35% of ecoregions. These spatially variable trajectories reflected regional differences in the drivers of change, uncertainty in some regions owing to poor spatial and temporal data coverage, and the dynamic nature of kelp populations. We conclude that although global drivers could be affecting kelp forests at multiple scales, local stressors and regional variation in the effects of these drivers dominate kelp dynamics, in contrast to many other marine and terrestrial foundation species.