Animal Housing—Barriers Overview

Barriers can be used to address dust and odor coming from animal housing. Barriers, or “windbreak walls” are used downwind of fans to reduce forward momentum of airflow, settle out dust particles, and push the exiting plume higher into the atmosphere.https://lib.dr.iastate.edu/extension_ag_pubs/1207/thumbnail.jp

Animal Housing—Biofilters Overview

Biofilters are used on mechanically ventilated livestock buildings to treat the ventilation air. A bed of biological material, normally wood chips, is created and the ventilation air flows through the material. Gases are absorbed by cultures of microbes that develop in the bed.This fact sheet is part of the Air Management Practices Assessment Tool (AMPAT) developed at Iowa State University and funded by the National Pork Board. Additional resources can be found on the AMPAT web page at: www.agronext.iastate.edu/ampathttps://lib.dr.iastate.edu/extension_ag_pubs/1208/thumbnail.jp

Animal Housing—Dietary Manipulation Overview

This fact sheet features diet manipulation as a management practice to address odor and emissions coming from animal housing and manure storage systems. Reducing nutrients in manure can lead to reductions in emissions. Reducing nutrients in manure is broken into two main areas, nutrient input reduction and nutrient form modification. This fact sheet describes both methods.This fact sheet is part of the Air Management Practices Assessment Tool (AMPAT) developed at Iowa State University and funded by the National Pork Board. Additional resources can be found on the AMPAT web page at: www.agronext.iastate.edu/ampathttps://lib.dr.iastate.edu/extension_ag_pubs/1210/thumbnail.jp

Animal Housing—Chimney Overview

The use of chimneys in animal housing systems can elevate odors and increase dispersion with increased wind speed and air turbulence at higher elevations.This fact sheet is part of the Air Management Practices Assessment Tool (AMPAT) developed at Iowa State University and funded by the National Pork Board. Additional resources can be found on the AMPAT web page at: www.agronext.iastate.edu/ampathttps://lib.dr.iastate.edu/extension_ag_pubs/1209/thumbnail.jp

Animal Housing—Electrostatic Precipitation Overview

Electrostatic precipitation can be used to reduce emissions, odor and dust from animal housing. Electrostatic systems work by imparting a negative charge on dust particles, causing them to stick to grounded surfaces such as gates, floors and walls.This fact sheet is part of the Air Management Practices Assessment Tool (AMPAT) developed at Iowa State University and funded by the National Pork Board. Additional resources can be found on the AMPAT web page at: www.agronext.iastate.edu/ampathttps://lib.dr.iastate.edu/extension_ag_pubs/1211/thumbnail.jp

Improvement to Air Management Practices Assessment Tool (AMPAT): Scientific Literature Database

The livestock and poultry production industry lacks a current, science-based guide for evaluation of air quality mitigation technologies. Therefore, we performed a science-based review of mitigation technologies using practical, stakeholders-oriented evaluation criteria to identify knowledge gaps/needs and focuses for future research efforts on technologies and areas with the greatest impact potential. Our objectives were to (1) present a recently completed Literature Database, and (2) identify and rank research needs and knowledge gaps based on the Literature Database. The Air Management Practices Tool (AMPAT) is web-based (available at www.agronext.iastate.edu/ampat) and provides an objective overview of mitigation practices best suited to address odor, gaseous, and particulate matter (PM) emissions at livestock operations. This tool helps livestock and poultry producers compare and explore different mitigation technologies. Simultaneously, a literature review of 267 papers was performed to evaluate mitigation technologies performance for emissions of odor, VOCs, NH3, H2S, PM, and GHGs and inform future research needs. Swine production systems were the most researched with 52% of the data entries. Housing and manure storage were the most researched sources of emissions with 41 and 43% of the data entries respectively. Biofilters were the most popular and farm tested technology for reducing emissions from animal housing. Aeration, anaerobic digestion, composting, diet manipulation and covers were the most researched technologies for reducing emission during manure storage and handling, with aeration being the most effective means of odor reduction farm scale tested. Injection or incorporation was the most farm tested and effective technology researched for land application

Flashlights: More than A Dozen High-Significance Microlensing Events of Extremely Magnified Stars in Galaxies at Redshifts z=0.7-1.5

Once only accessible in nearby galaxies, we can now study individual stars across much of the observable universe aided by galaxy-cluster gravitational lenses. When a star, compact object, or multiple such objects in the foreground galaxy-cluster lens become aligned, they can magnify a background individual star, and the timescale of a magnification peak can limit its size to tens of AU. The number and frequency of microlensing events therefore opens a window into the population of stars and compact objects, as well as high-redshift stars. To assemble the first statistical sample of stars in order to constrain the initial mass function (IMF) of massive stars at redshift z=0.7-1.5, the abundance of primordial black holes in galaxy-cluster dark matter, and the IMF of the stars making up the intracluster light, we are carrying out a 192-orbit program with the Hubble Space Telescope called "Flashlights," which is now two-thirds complete owing to scheduling challenges. We use the ultrawide F200LP and F350LP long-pass WFC3 UVIS filters and conduct two 16-orbit visits separated by one year. Having an identical roll angle during both visits, while difficult to schedule, yields extremely clean subtraction. Here we report the discovery of more than a dozen bright microlensing events, including multiple examples in the famous "Dragon Arc" discovered in the 1980s, as well as the "Spocks" and "Warhol" arcs that have hosted already known supergiants. The ultradeep observer-frame ultraviolet-through-optical imaging is sensitive to hot stars, which will complement deep James Webb Space Telescope infrared imaging. We are also acquiring Large Binocular Telescope LUCI and Keck-I MOSFIRE near-infrared spectra of the highly magnified arcs to constrain their recent star-formation histories

A shot in the Dark (Ages): a faint galaxy at z=9.76z=9.76 confirmed with JWST

The appearance of galaxies over the first billion years after the Big Bang is believed to be responsible for the last dramatic change in the state of the Universe. Ultraviolet photons from galaxies within this time period - the Epoch of Reionization - ionized intergalactic Hydrogen, rendering the Universe transparent to UV radiation and ending the so-called cosmic Dark Ages, sometime after redshift $z\sim8$. The majority of ionizing photons in the first few hundred Myrs of cosmic history are thought to derive from galaxies significantly fainter than the characteristic luminosity $L^{*}$. These faint galaxies are thought to be surrounded by sufficient neutral gas to prevent the escape of the Lyman-$\alpha$ photons that would allow confirmation with current observatories. Here we demonstrate the power of the recently commissioned James Webb Space Telescope to transform our understanding of the sources of reionization, by reporting the first spectroscopic confirmation of a very low luminosity ($\sim0.05 L^{*}$) galaxy at $z=9.76$, observed 480 Myr after the Big Bang, via the detection of the Lyman-break and redward continuum with the NIRSpec and NIRCam instruments. The galaxy JD1 is gravitationally magnified by a factor of $\mu\sim13$ by the foreground cluster A2744. The power of JWST and lensing allows us to peer deeper than ever before into the cosmic Dark Ages, revealing the compact ($\sim$150 pc) and complex morphology and physical properties of an ultrafaint galaxy ($M_{\rm UV}=-17.45$).Comment: Submitted to Nature. 34 pages, 4 main figures, 1 supplementary figure, 2 supplementary tables. Comments are welcom

Clouds, circulation and climate sensitivity

Fundamental puzzles of climate science remain unsolved because of our limited understanding of how clouds, circulation and climate interact. One example is our inability to provide robust assessments of future global and regional climate changes. However, ongoing advances in our capacity to observe, simulate and conceptualize the climate system now make it possible to fill gaps in our knowledge. We argue that progress can be accelerated by focusing research on a handful of important scientific questions that have become tractable as a result of recent advances. We propose four such questions below; they involve understanding the role of cloud feedbacks and convective organization in climate, and the factors that control the position, the strength and the variability of the tropical rain belts and the extratropical storm tracks

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements