57 research outputs found
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Estimating the Effects of Selected Sanitary and Phytosanitary Measures and Technical Barriers to Trade on US-EU Agricultural Trade
This study investigates the effects of non-tariff measures (NTM)-specifically, sanitary and phytosanitary measures and technical barriers to trade-on agricultural trade between the United States and the European Union (EU). Along with tariff reduction, the removal of NTMs has emerged as a key focus of negotiations in the U.S.-EU Transatlantic Trade and Investment Partnership
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Testing a Prototype Ion Probe for Europa's Plasma Interaction: Colorado Europa Langmuir Probe
The Colorado Europa Langmuir Probe (CELP) is a plasma instrument de- signed to characterize Europa’s plasma interaction to derive external magnetic fields. In order to accomplish the proposed science goal, CELP must be able to measure ion density, temperature, and flow direction. To do this, a design simi- lar to a cylindrical Faraday Cup is utilized, using three selection grids and four collecting surfaces. Necessary capabilities of the instrument include angular reconstruction in the yaw axis (theta) with respect to an ion beam, and in the roll axis (phi), both with picoamp current resolution. This study involved test- ing a prototype Ion Langmuir Probe using an ion beam in the lab. Data analysis shows angular resolutions of ±10° in theta and ±5° in phi [1] at ion tempera- tures of 400 eV and 900 eV, with currents on the order of 0.01 nA and 100 nA. The instrument must also show current resolution as low as the minimum ex- pected ionospheric currents at Europa of 10 pA/cm2 [2]. Using our experimental setup, current resolution at values as low as 0.1 pA/cm2 was observed. Along with achieving angular and current resolution goals, plots were produced that successfully match experimental data with analytical and simulation models, and the specified goals were achieved
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Agriculture in the Transatlantic Trade and Investment Partnership: Tariffs, Tariff-Rate Quotas, and Non-Tariff Measures
This study assesses the potential effects of the U.S.-EU Transatlantic Trade and Investment Partnership on agriculture under three broad scenarios: complete removal of tariffs and tariff-rate quotas; elimination of non-tariff measures along with tariffs and tariff-rate quotas; and a lowering of the willingness of consumers to purchase imported goods previously limited by non-tariff measures
Modeling Early Stage Bone Regeneration With Biomimetic Electrospun Fibrinogen Nanofibers and Adipose-Derived Mesenchymal Stem Cells
The key events of the earliest stages of bone regeneration have been described in vivo although not yet modeled in an in vitro environment, where mechanistic cell-matrix-growth factor interactions can be more effectively studied. Here, we explore an early-stage bone regeneration model where the ability of electrospun fibrinogen (Fg) nanofibers to regulate osteoblastogenesis between distinct mesenchymal stem cells populations is assessed. Electrospun scaffolds of Fg, polydioxanone (PDO), and a Fg:PDO blend were seeded with adipose-derived mesenchymal stem cells (ASCs) and grown for 7-21 days in osteogenic differentiation media or control growth media. Scaffolds were analyzed weekly for histologic and molecular evidence of osteoblastogenesis. In response to osteogenic differentiation media, ASCs seeded on the Fg scaffolds exhibit elevated expression of multiple genes associated with osteoblastogenesis. Histologic stains and scanning electron microscopy demonstrate widespread mineralization within the scaffolds, as well as de novo type I collagen synthesis. Our data demonstrates that electrospun Fg nanofibers support ASC osteogenic differentiation, yet the scaffold itself does not appear to be osteoinductive. Together, ASCs and Fg recapitulate early stages of bone regeneration ex vivo and presents a prospective autologous therapeutic approach for bone repair
Development of the Low Frequency Telescope Focal Plane Detector Modules for LiteBIRD
LiteBIRD is a JAXA-led strategic large-class satellite mission designed to
measure the polarization of the cosmic microwave background and Galactic
foregrounds from 34 to 448 GHz across the entire sky from L2 in the late 2020s.
The scientific payload includes three telescopes which are called the low-,
mid-, and high-frequency telescopes each with their own receiver that covers a
portion of the mission's frequency range. The low frequency telescope will map
synchrotron radiation from the Galactic foreground and the cosmic microwave
background. We discuss the design, fabrication, and characterization of the
low-frequency focal plane modules for low-frequency telescope, which has a
total bandwidth ranging from 34 to 161 GHz. There will be a total of 4
different pixel types with 8 overlapping bands to cover the full frequency
range. These modules are housed in a single low-frequency focal plane unit
which provides thermal isolation, mechanical support, and radiative baffling
for the detectors. The module design implements multi-chroic lenslet-coupled
sinuous antenna arrays coupled to transition edge sensor bolometers read out
with frequency-domain mulitplexing. While this technology has strong heritage
in ground-based cosmic microwave background experiments, the broad frequency
coverage, low optical loading conditions, and the high cosmic ray background of
the space environment require further development of this technology to be
suitable for LiteBIRD. In these proceedings, we discuss the optical and
bolometeric characterization of a triplexing prototype pixel with bands
centered on 78, 100, and 140 GHz.Comment: SPIE Astronomical Telescope + Instrumentation (AS22
Agriculture in the Trans-Pacific Partnership
The Trans-Pacific Partnership is a trade and investment agreement under negotiation by 12 countries in the Pacific Rim. This report assesses this partnership's potential impacts on the region's agriculture in 2025
Making maps of cosmic microwave background polarization for B-mode studies: The POLARBEAR example
Analysis of cosmic microwave background (CMB) datasets typically requires some filtering of the raw time-ordered data. For instance, in the context of ground-based observations, filtering is frequently used to minimize the impact of low frequency noise, atmospheric contributions and/or scan synchronous signals on the resulting maps. In this work we have explicitly constructed a general filtering operator, which can unambiguously remove any set of unwanted modes in the data, and then amend the map-making procedure in order to incorporate and correct for it. We show that such an approach is mathematically equivalent to the solution of a problem in which the sky signal and unwanted modes are estimated simultaneously and the latter are marginalized over. We investigated the conditions under which this amended map-making procedure can render an unbiased estimate of the sky signal in realistic circumstances. We then discuss the potential implications of these observations on the choice of map-making and power spectrum estimation approaches in the context of B-mode polarization studies. Specifically, we have studied the effects of time-domain filtering on the noise correlation structure in the map domain, as well as impact it may haveon the performance of the popular pseudo-spectrum estimators. We conclude that although maps produced by the proposed estimators arguably provide the most faithful representation of the sky possible given the data, they may not straightforwardly lead to the best constraints on the power spectra of the underlying sky signal and special care may need to be taken to ensure this is the case. By contrast, simplified map-makers which do not explicitly correct for time-domain filtering, but leave it to subsequent steps in the data analysis, may perform equally well and be easier and faster to implement. We focused on polarization-sensitive measurements targeting the B-mode component of the CMB signal and apply the proposed methods to realistic simulations based on characteristics of an actual CMB polarization experiment, POLARBEAR. Our analysis and conclusions are however more generally applicable. \ua9 ESO, 2017
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Advancements in Microwave Optics for Measuring Polarization Anisotropies in the Cosmic Microwave Background
The temperature and polarization anisotropies in the Cosmic Microwave Background (CMB) are direct probes into the physics of the early universe. Increasingly sensitive experiments aim to determine the tensor-to-scalar ratio r through measurement of an impossibly faint B-mode polarized signal shrouded by galactic foregrounds. A direct measurement of primordial B-mode polarization will be a measurement of the energy scale of inflation, unlocking an essential piece of the cosmological puzzle. Next-generation CMB experiments employ a large number of highly sensitive detectors in an attempt to find r and further constrain the cosmological parameters. Such a measurement requires not just high sensitivity to the CMB polarized signal, but large experimental bandwidth to characterize the polarized galactic dust and synchrotron radiation foreground signals. For experiments using lenslet-coupled planar antenna detector array designs, reflection off the surface of the lenslet must be minimized over a given bandwidth to maximize the measured CMB signal. To this end, antireflection (AR) coatings for lenslets were developed for 30/40 GHz Simons Observatory low-frequency detectors, along with next-generation prototype coatings for 90/150 and 220/270 GHz arrays. The JAXA-led space-based mission LiteBIRD will utilize lenslet-coupled sinuous antenna arrays and TES bolometers for frequencies ranging from 40-195 GHz, necessitating broadband lenslet AR coatings that are robust to launch vibrations and differential thermal contraction. To meet these requirements, a metamaterial AR surface has been proposed. A metamaterial coating designed for the LiteBIRD LF-3 band has been laser etched onto a flat surface, achieving 98% in-band transmission. A six-axis positioning system is used to etch the metamaterial pattern onto a sphere, and a completed prototype LF-3 lenslet is expected to be etched in late 2023. Details of the metamaterial design and the etch process are discussed. Cosmic rays at the Lagrange point L2 pose a threat to LiteBIRD’s sensitivity, as they produce a white noise component that cannot be fully deconstructed in analysis. To mitigate this cosmic ray white noise component, on-chip mitigations have been developed for the purpose of minimizing thermal diffusion from the silicon detector wafer to the TES bolometer detectors. Lastly, the mechanical design and fabrication of a continuously rotating warm half-wave plate for the POLARBEAR-2a experiment, used to minimize noise in large-angular-scale measurements from atmospheric fluctuations, are discussed
Reducing Transatlantic Barriers on U.S.-EU Agri-food Trade: What Are the Possible Gains?
In recent years, the EU and the U.S. have engaged in discussions to lower trade and investment barriers and strengthen transatlantic integration. For food and agricultural trade, non-tariff measures (NTMs) such as sanitary and phytosanitary measures (SPS) stand out as significant barriers. This study combines sector-level econometric modeling with an agriculture-focused computable generable equilibrium (CGE) model to simulate various transatlantic liberalization scenarios on U.S.-EU agri-food trade. The simulations quantify the effect from tariff removal and addressing NTMs. The magnitude of the gains depend upon the level of tariff liberalization, the depth of integration, and possible consumer demand changes
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