158 research outputs found
Conceptual Design of the Modular Detector and Readout System for the CMB-S4 survey experiment
We present the conceptual design of the modular detector and readout system
for the Cosmic Microwave Background Stage 4 (CMB-S4) ground-based survey
experiment. CMB-S4 will map the cosmic microwave background (CMB) and the
millimeter-wave sky to unprecedented sensitivity, using 500,000 superconducting
detectors observing from Chile and Antarctica to map over 60 percent of the
sky. The fundamental building block of the detector and readout system is a
detector module package operated at 100 mK, which is connected to a readout and
amplification chain that carries signals out to room temperature. It uses
arrays of feedhorn-coupled orthomode transducers (OMT) that collect optical
power from the sky onto dc-voltage-biased transition-edge sensor (TES)
bolometers. The resulting current signal in the TESs is then amplified by a
two-stage cryogenic Superconducting Quantum Interference Device (SQUID) system
with a time-division multiplexer to reduce wire count, and matching
room-temperature electronics to condition and transmit signals to the data
acquisition system. Sensitivity and systematics requirements are being
developed for the detector and readout system over a wide range of observing
bands (20 to 300 GHz) and optical powers to accomplish CMB-S4's science goals.
While the design incorporates the successes of previous generations of CMB
instruments, CMB-S4 requires an order of magnitude more detectors than any
prior experiment. This requires fabrication of complex superconducting circuits
on over 10 square meters of silicon, as well as significant amounts of
precision wiring, assembly and cryogenic testing.Comment: 25 pages, 15 figures, presented at and published in the proceedings
of SPIE Astronomical Telescopes and Instrumentation 202
Evasion of anti-growth signaling: a key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds
The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and KrĂŒppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally-occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally-occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting
Greenhouse gas emission associated with sugar production in southern Brazil
<p>Abstract</p> <p>Background</p> <p>Since sugarcane areas have increased rapidly in Brazil, the contribution of the sugarcane production, and, especially, of the sugarcane harvest system to the greenhouse gas emissions of the country is an issue of national concern. Here we analyze some data characterizing various activities of two sugarcane mills during the harvest period of 2006-2007 and quantify the carbon footprint of sugar production.</p> <p>Results</p> <p>According to our calculations, 241 kg of carbon dioxide equivalent were released to the atmosphere per a ton of sugar produced (2406 kg of carbon dioxide equivalent per a hectare of the cropped area, and 26.5 kg of carbon dioxide equivalent per a ton of sugarcane processed). The major part of the total emission (44%) resulted from residues burning; about 20% resulted from the use of synthetic fertilizers, and about 18% from fossil fuel combustion.</p> <p>Conclusions</p> <p>The results of this study suggest that the most important reduction in greenhouse gas emissions from sugarcane areas could be achieved by switching to a green harvest system, that is, to harvesting without burning.</p
Mechanisms of Formation and Destruction of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Heterogeneous Systems
CMB-S4: Forecasting Constraints on Primordial Gravitational Waves
CMB-S4---the next-generation ground-based cosmic microwave background (CMB)
experiment---is set to significantly advance the sensitivity of CMB
measurements and enhance our understanding of the origin and evolution of the
Universe, from the highest energies at the dawn of time through the growth of
structure to the present day. Among the science cases pursued with CMB-S4, the
quest for detecting primordial gravitational waves is a central driver of the
experimental design. This work details the development of a forecasting
framework that includes a power-spectrum-based semi-analytic projection tool,
targeted explicitly towards optimizing constraints on the tensor-to-scalar
ratio, , in the presence of Galactic foregrounds and gravitational lensing
of the CMB. This framework is unique in its direct use of information from the
achieved performance of current Stage 2--3 CMB experiments to robustly forecast
the science reach of upcoming CMB-polarization endeavors. The methodology
allows for rapid iteration over experimental configurations and offers a
flexible way to optimize the design of future experiments given a desired
scientific goal. To form a closed-loop process, we couple this semi-analytic
tool with map-based validation studies, which allow for the injection of
additional complexity and verification of our forecasts with several
independent analysis methods. We document multiple rounds of forecasts for
CMB-S4 using this process and the resulting establishment of the current
reference design of the primordial gravitational-wave component of the Stage-4
experiment, optimized to achieve our science goals of detecting primordial
gravitational waves for at greater than , or, in the
absence of a detection, of reaching an upper limit of at CL.Comment: 24 pages, 8 figures, 9 tables, submitted to ApJ. arXiv admin note:
text overlap with arXiv:1907.0447
The posthuman way of war
Recent interventions from a âposthumanistâ or ânew materialistâ perspective have highlighted the embedded character of human systems within a âpanarchyâ of human and non-human systems. This article brings attention to a very particular element of materiality, one with a profound significance for issues of security â relations between human and non-human animals in instances of conflict. It is an indication of the deeply human-centred character of both international relations and security studies that almost none of the central texts mention the very significant roles that non-human animals have in the conduct of war. We argue that the character of war would have been radically different but for the forced participation by an enormous range of non-human animals. Even though, with the improvements in transportation over the last century, non-human animals are less evident in the context of the movement of people and equipment, they still play a significant number of roles in the contemporary war-machines of wealthy countries. Drawing on literature from critical animal studies, sociology and memoirs, this article discusses the enormous variety of roles that non-human animals have played in the conduct of war, and examines the character of humanânon-human animal relations in times of war
Impact of different drying parameters on color, ÎČ-carotene, antioxidant activity and minerals of apricot (Prunus armeniacaL.)
CMB-S4: Forecasting Constraints on Primordial Gravitational Waves
Abstract: CMB-S4âthe next-generation ground-based cosmic microwave background (CMB) experimentâis set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the universe. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semianalytic projection tool, targeted explicitly toward optimizing constraints on the tensor-to-scalar ratio, r, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2â3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments, given a desired scientific goal. To form a closed-loop process, we couple this semianalytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for r > 0.003 at greater than 5Ï, or in the absence of a detection, of reaching an upper limit of r < 0.001 at 95% CL
Pollutant formation and emissions from cement kiln stack using a solid recovered fuel from municipal solid waste
The thermal decomposition of a Solid Recovered Fuel (SRF) has been studied by two techniques. First, laboratory-scale experiments were performed in a horizontal furnace in which different atmospheres are studied to analyze the dioxins and furans (PCDD/Fs) evolved from the decomposition of the material. Sulfur presence is revealed to be important in PCDD/Fs formation. In the second technique, the emission of various pollutants (PAHs, PCDD/Fs, metals, acid gases âŠ) were determined in a cement kiln fed on different proportions of SRF material, and where a maximum feed rate of 15000 kg SRF/h was achieved. In the laboratory furnace the dioxin toxicity revealed a maximum when the amount of oxygen in the atmosphere increased until approximately stoichiometric conditions. In the cement kiln, all emitted pollutants are under the legal limits. No correlation between SRF input and metal emission was observed.Support for this work was provided by CEMEX ESPANA, S.A., a company owned by the CEMEX group (http://www.cemex.com). Authors acknowledge the financial support for this work provided by PROMETEO/2009/043/FEDER and ACOMP2010/075 of Generalitat Valenciana (Spain) and CTQ2008-05520 (Spanish MCI)
Potential role of chlorination pathways in PCDD/F formation in a municipal waste incinerator
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