Ammonia Emissions from USA Broiler Chicken Barns Managed with New Bedding, Built-up Litter, or Acid-Treated Litter

Poultry producers in the United States have attempted to maintain barn aerial ammonia (NH3) levels below 25 ppm to improve air quality, and more recently to decrease aerial emissions to the atmosphere. Our objective was to investigate the influence of litter management strategies on NH3 emissions from commercial broiler barns employing new bedding, acid-treated built-up litter (sodium bisulphate), or untreated built-up litter (normal practice). Nearly 400 barn-days of NH3 emissions data were collected from 12 broiler barns on four farms monitored in 48-hour episodes over one year. On each study farm, the barns were paired for repetition of conditions. Emission was calculated as the product of gas concentration of the exhaust air and barn ventilation rate. Use of new bedding for every flock led to consistently lower NH3 emission (averaging 0.35 g NH3/(bird d)) at day 21 of the 42-day flock grow-outs, followed by flocks raised on the annual cleanout with new bedding (0.52 g NH3/(bird d)). Built-up litter without any treatment had the highest emission (0.73 g NH3/(bird d)), followed by the built-up litter with acid treatment (0.63 g NH3/(bird d)). One study site was managed with two barns using litter treatment and two identical barns with untreated, built-up litter for a side-by-side comparison of results under field conditions. Ammonia emissions from treated built-up litter barns were similar to those from untreated built-up litter barns, however, the temporal pattern of emissions provided evidence that ammonia held in the acid-treated litter at the beginning of the flock was released during the latter period of the flock cycle

Conserving Montana’s Birds And Their Habitats Through Partnerships

The Montana Bird Conservation Partnership is a consortium of representatives from state, tribal, and federal agencies, non-governmental organizations, and individuals who are dedicated to conserving birds and their habitats in Montana. Our goals are to work collaboratively to keep common birds common and to conserve, protect and restore sensitive species and habitats. We work to recognize the social and economic value of birds to the people of Montana. We also use the best available science to identify conservation opportunities. Over 300 species of birds regularly breed, winter, or migrate through Montana. Of these, 82 are considered to have sensitive or at-risk populations. Montana’s birds are threatened by habitat loss stemming from changing land use practices and energy and subdivision development. Global climate change may exacerbate these threats. We will present current Montana Bird Conservation Partnership projects, our action plan, focal species initiatives, and examples of successful conservation-in-action projects. Find out how you and/ or your organization can get involved at the local or state level. Learn more about the most exciting and forward-thinking bird partnership in the region

Physiological identification of afferent fibers and postsynaptic sensory neurons in the spinal cord of the intact, awake cat

A method was developed to record from spinal cord cells in the awake, intact, partially restrained cat. Units were classified as afferent fibers or postsynaptic cells based on their ability to follow 100-Hz peripheral stimulation, the duration and configuration of the action potential waveform, and the number of spikes evoked by a single electrical pulse. These criteria are supported by independent observations of the location of the recording site, size of the receptive field, and adequate stimulus. Of 84 cutaneously activated units, 29 were classified as afferent fibers, 28 as postsynaptic cells, and 27 were not classified. No cutaneously activated unit was spontaneously active. In contract, all 28 units (7 postsynaptic and 21 not classified) responding to joint position or movement were spontaneously active (5 to 40 Hz). No unit responded to both cutaneous and proprioceptive inputs. Evidence for convergence of cutaneous input from different types of receptors was limited to five postsynaptic neurons that responded to hair movement and to stimuli applied to the skin; two of these cells responded differentially to noxious pinch. Two of 24 postsynaptic cutaneous units ceased responding to electrical cutaneous stimuli when the cat was eating. The responses of 29 primary afferent fibers were not altered by the behavior of the cat. These results suggest that, in the awake cat (i) criteria based on neuronal responsiveness and action potential waveform can be used to distinguish adequately between afferent fibers and postsynaptic cells; and (ii) there is a tonic inhibitory control, greater than in the anesthetized or spinally transected cat, that varies with behavioral state and is directed primarily at spinal neurons receiving cutaneous input.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27419/1/0000457.pd

Breaking the Curve with CANDELS: A Bayesian Approach to Reveal the Non-Universality of the Dust-Attenuation Law at High Redshift

Dust attenuation affects nearly all observational aspects of galaxy evolution, yet very little is known about the form of the dust-attenuation law in the distant Universe. Here, we model the spectral energy distributions (SEDs) of galaxies at z = 1.5--3 from CANDELS with rest-frame UV to near-IR imaging under different assumptions about the dust law, and compare the amount of inferred attenuated light with the observed infrared (IR) luminosities. Some individual galaxies show strong Bayesian evidence in preference of one dust law over another, and this preference agrees with their observed location on the plane of infrared excess (IRX, $L_{\text{TIR}}/L_{\text{UV}}$) and UV slope ($\beta$). We generalize the shape of the dust law with an empirical model, $A_{\lambda,\delta}=E(B-V)\ k_\lambda\ (\lambda/\lambda_V)^\delta$ where $k_\lambda$ is the dust law of Calzetti et al. (2000), and show that there exists a correlation between the color excess ${E(B-V)}$ and tilt $\delta$ with ${\delta=(0.62\pm0.05)\log(E(B-V))}$+ ${(0.26~\pm~0.02)}$. Galaxies with high color excess have a shallower, starburst-like law, and those with low color excess have a steeper, SMC-like law. Surprisingly, the galaxies in our sample show no correlation between the shape of the dust law and stellar mass, star-formation rate, or $\beta$. The change in the dust law with color excess is consistent with a model where attenuation is caused by by scattering, a mixed star-dust geometry, and/or trends with stellar population age, metallicity, and dust grain size. This rest-frame UV-to-near-IR method shows potential to constrain the dust law at even higher ($z>3$) redshifts.Comment: 20 pages, 18 figures, resubmitted to Ap