155 research outputs found
Impact of Hybrid Energy Storage System Topology on Performance: Exploration for Hydropower Hybrids
We investigate the technical performance of six HESS topologies integrated with run-of-river (ROR) hydropower to provide frequency support. We choose ROR hydropower because there are 23 GW of installed ROR hydropower in the U.S. and integrating these plants with energy storage could boost their contribution to grid services. We focus on HESSs composed of batteries and ultra-capacitors because batteries are cost effective for storing energy but degrade more quickly as a function of cycling. In contrast, ultra-capacitors can be cycled millions of times and are cost effective for quick injections of power. We find that active HESS topologies demonstrate the best overall improvement to grid frequency during a contingency while adhering to the power ramping limits of the HESS devices. Future work will investigate other services to identify if one HESS topology performs best for all services of interest or, more likely, different HESS topologies are best suited for specific services
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30-Arcsecond monthly climate surfaces with global land coverage
Monthly total precipitation and mean temperature climate surfaces, gridded to 30-arcseconds (≈1 km at the
equator) and available for all global land areas, are presented. These datasets are generated with a Delta downscaling
method, using the 30-arcsecond WorldClim climatologies to scale monthly anomaly grids. For monthly mean temperature,
the anomalies are constructed from both the Climate Research Unit (CRU) and Willmott & Matsuura (W&M) 0.5 degree
time-series datasets, whereas for monthly precipitation Global Precipitation Climatology Centre (GPCC) data are also used.
The 0.5 degree anomalies are then interpolated to the 30-arcsecond resolution. Use of piecewise cubic Hermite interpolating
polynomials (PCHIP) to interpolate the anomaly grids results in more physically representative Delta downscaled surfaces,
compared to bilinear and cubic spline interpolation. The Delta downscaled products are compared to Global Historical
Climatology Network (GHCN) station records for six test regions distributed globally. In this analysis, the Delta grids
produced using the W&M time-series dataset perform better than grids produced using GPCC or CRU. Using Oregon,
USA as a test region, the Delta downscaled datasets are compared to the Parameter-elevation Regressions on Independent
Slopes Model (PRISM) datasets. For monthly precipitation, PRISM performs better than each of the three Delta downscaled
datasets, but for mean temperature both Delta downscaled datasets outperform PRISM. Through computing the Pearson
product–moment correlation coefficient between GHCN station delineated errors in the WorldClim climatologies and the
Delta downscaled W&M data, it is shown that performance of the Delta grids corresponds strongly to performance of the
reference climatologies. Therefore, future improvement of the 30-arcsecond Delta grids described in this article is strongly
tied to advances in the high-resolution climatological data for all global land surfaces. The Delta downscaled datasets
discussed herein are open-source and freely distributed at http://www.globalclimatedata.org.This is the publisher’s final pdf. The article is copyrighted by the Royal Meteorological Society and published by John Wiley & Sons Ltd. It can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291097-0088.Keywords: high resolution, precipitation, monthly time-series, mean temperature, downscaling, global climate dat
Dopamine Beta Hydroxylase Genotype Identifies Individuals Less Susceptible to Bias in Computer-Assisted Decision Making
Computerized aiding systems can assist human decision makers in complex tasks but can impair performance when they provide incorrect advice that humans erroneously follow, a phenomenon known as “automation bias.” The extent to which people exhibit automation bias varies significantly and may reflect inter-individual variation in the capacity of working memory and the efficiency of executive function, both of which are highly heritable and under dopaminergic and noradrenergic control in prefrontal cortex. The dopamine beta hydroxylase (DBH) gene is thought to regulate the differential availability of dopamine and norepinephrine in prefrontal cortex. We therefore examined decision-making performance under imperfect computer aiding in 100 participants performing a simulated command and control task. Based on two single nucleotide polymorphism (SNPs) of the DBH gene, −1041 C/T (rs1611115) and 444 G/A (rs1108580), participants were divided into groups of low and high DBH enzyme activity, where low enzyme activity is associated with greater dopamine relative to norepinephrine levels in cortex. Compared to those in the high DBH enzyme activity group, individuals in the low DBH enzyme activity group were more accurate and speedier in their decisions when incorrect advice was given and verified automation recommendations more frequently. These results indicate that a gene that regulates relative prefrontal cortex dopamine availability, DBH, can identify those individuals who are less susceptible to bias in using computerized decision-aiding systems
A distinct role for B1b lymphocytes in T cell-independent immunity
Pathogenesis of infectious disease is not only determined by the virulence of the microbe but also by the immune status of the host. Vaccination is the most effective means to control infectious diseases. A hallmark of the adaptive immune system is the generation of B cell memory, which provides a long-lasting protective antibody response that is central to the concept of vaccination. Recent studies revealed a distinct function for B1b lymphocytes, a minor subset of mature B cells that closely resembles that of memory B cells in a number of aspects. In contrast to the development of conventional B cell memory, which requires the formation of germinal centers and T cells, the development of B1b cell-mediated long-lasting antibody responses occurs independent of T cell help. T cell-independent (TI) antigens are important virulence factors expressed by a number of bacterial pathogens, including those associated with biological threats. TI antigens cannot be processed and presented to T cells and therefore are known to possess restricted T cell-dependent (TD) immunogenicity. Nevertheless, specific recognition of TI antigens by B1b cells and the highly protective antibody responses mounted by them clearly indicate a crucial role for this subset of B cells. Understanding the mechanisms of long-term immunity conferred by B1b cells may lead to improved vaccine efficacy for a variety of TI antigens
A New DREADD Facilitates the Multiplexed Chemogenetic Interrogation of Behavior
DREADDs are chemogenetic tools widely used to remotely control cellular signaling, neuronal activity and behavior. Here we used a structure-based approach to develop a new Gi coupled DREADD using the kappa-opioid receptor as template (KORD) that is activated by the pharmacologically inert ligand salvinorin B (SALB). Activation of virally-expressed KORD in several neuronal contexts robustly attenuated neuronal activity and modified behaviors. Additionally, co-expression of the KORD and the Gq coupled M3-DREADD within the same neuronal population facilitated the sequential and bi-directional remote control of behavior. The availability of DREADDs activated by different ligands provides enhanced opportunities for investigating diverse physiological systems using multiplexed chemogenetic actuators
The James Webb Space Telescope Mission: Optical Telescope Element Design, Development, and Performance
The James Webb Space Telescope (JWST) is a large, infrared space telescope
that has recently started its science program which will enable breakthroughs
in astrophysics and planetary science. Notably, JWST will provide the very
first observations of the earliest luminous objects in the Universe and start a
new era of exoplanet atmospheric characterization. This transformative science
is enabled by a 6.6 m telescope that is passively cooled with a 5-layer
sunshield. The primary mirror is comprised of 18 controllable, low areal
density hexagonal segments, that were aligned and phased relative to each other
in orbit using innovative image-based wavefront sensing and control algorithms.
This revolutionary telescope took more than two decades to develop with a
widely distributed team across engineering disciplines. We present an overview
of the telescope requirements, architecture, development, superb on-orbit
performance, and lessons learned. JWST successfully demonstrates a segmented
aperture space telescope and establishes a path to building even larger space
telescopes.Comment: accepted by PASP for JWST Overview Special Issue; 34 pages, 25
figure
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
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