816 research outputs found

    Wet Corn Gluten Feed Supplementation of Calves Grazing Corn Residue

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    Incremental levels of wet corn gluten feed were fed to calves grazing corn residues. Based on statistical and economical analysis of the data collected, feeding wet corn gluten feed (5.0-6.5 lb/ head/day; DM basis) will increase stocking rate on corn residue and reduce winter costs by 11%. Given that 3.5 lb DM/day wet corn gluten feed will meet the protein and phosphorus needs of calves, and feeding above 6.0 lb/d will not increase gains, wet corn gluten feed should be fed at 3.5-6.0 lb DM/day, producing gains from 1.28- 1.88 lb/day

    Polyparameter linear free energy relationship for wood char–water sorption coefficients of organic sorbates

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    Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Environmental Toxicology and Chemistry 34 (2015): 1464-1471, doi:10.1002/etc.2951.Black carbons (BCs), including soots, chars, activated carbons, and engineered nanocarbons, have different surface properties, but we do not know to what extent these affect their sorbent properties. To evaluate this for an environmentally ubiquitous form of BC, biomass char, we probed the surface of a well-studied wood char using 14 sorbates exhibiting diverse functional groups and then fit the data with a polyparameter linear free energy relationship (ppLFER) to assess the importance of the various possible sorbate-char surface interactions. Sorption from water to water-wet char evolved with the sorbate's degree of surface saturation and depended on only a few sorbate parameters: log Kd(L/kg) = [(4.03 ± 0.14) + (-0.15 ± 0.04) log ai)] V + [(-0.28 ± 0.04) log ai)] S + (-5.20 ± 0.21) B where ai is the aqueous saturation of the sorbate i, V is McGowan’s characteristic volume, S reflects polarity, and B represents the electron-donation basicity. As generally observed for activated carbon, the sorbate’s size encouraged sorption from water to the char, while its electron donation/proton acceptance discouraged sorption from water. However, the magnitude and saturation dependence differed significantly from what has been seen for activated carbons, presumably reflecting the unique surface chemistries of these two BC materials and suggesting BC-specific sorption coefficients will yield more accurate assessments of contaminant mobility and bioavailability and evaluation of a site's response to remediation.This material is based upon work supported by the U.S. Army Corps of Engineering, Humphreys Engineer Center Support Activity under Contract No. W912HQ-10-C-0005 awarded as part of the SERDP program.2016-05-1

    A Systems Approach to Production From Weaning to Harvest

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    Although some summer and fall calving occurs, the majority of calves in the Northern States are born in the spring. Therefore, to have a consistent supply of feeders entering feedlots, a variety of stocker programs are used. About 30% of calves produced in the U. S. enter the feedlot as calf-feds. Some of these calf-feds are weaned and enter the feedlot 30 to 40 days later. It is also common for calves to be backgrounded two to six months before entering the feedlot. Many calves enter yearling programs. These cattle are nutritionally restricted to varying degrees and for various times. They make compensatory gain on grass and then make additional compensatory gain when they enter the feedlot (Klopfenstein et al., 1999). Because of the great variety of cattle production systems, cattle enter the feedlot at varying weights, ages and nutritional backgrounds. Ranchers have an opportunity to add value to their calves by backgrounding them. Ranches have forage resources. It may be possible, in some cases at least, to optimize the use of those forage resources by backgrounding calves produced on the ranch. We have conducted research on backgrounding programs over the past 15 to 20 years. We also feed 600 or more calf-feds each year. We want to share those observations and the appropriate economics with you. Compensatory Gain on Grass. In the mid 1980\u27s we conducted a two year study on compensatory gain (Lewis et al., 1990). We had three levels of winter gain on crop residues and measured summer gain. The cattle made 88% compensation. More restricted cattle in the winter made up 88% of the gain they did not make relative to the higher gaining winter calves. Five years of data were summarized from our Scottsbluff Research Center (Hayden et al., 1997). Calves were fed for two rates of winter gain. Slow gaining calves grazed cornstalks and fast gaining calves were limit-fed a high energy diet. They then grazed (summer) for two or four months. The calves that grazed season long (four months) made 57.6% compensation. Those that grazed only two months made 38.2% compensation. During the last two years of the study, British breed steers were compared to Continental cross steers. Compensation was the same (54.3 and 52.5%) suggesting that frame size does not affect degree of compensation

    Hydrologic controls on seasonal and inter-annual variability of Congo River particulate organic matter source and reservoir age

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    We present dissolved organic carbon (DOC) concentrations, particulate organic matter (POM) composition (δ13C, δ15N, ∆14C, N/C), and particulate glycerol dialkyl glycerol tetraether (GDGT) distributions from a 34-month time-series near the mouth of the Congo River. An end-member mixing model using δ13C and N/C indicates that exported POM is consistently dominated by C3 rainforest soil sources, with increasing contribution from C3 vegetation and decreasing contribution from phytoplankton at high discharge. Large C4 inputs are never observed despite covering ≈ 13% of the catchment. Low and variable ∆14C values during 2011 [annual mean = (− 148 ± 82) ‰], when discharge from left-bank tributaries located in the southern hemisphere reached record lows, likely reflect a bias toward pre-aged POM derived from the Cuvette Congolaise swamp forest. In contrast, ∆14C values were stable near − 50‰ between January and June 2013, when left-bank discharge was highest. We suggest that headwater POM is replaced and/or diluted by C3 vegetation and pre-aged soils during transit through the Cuvette Congolaise, whereas left-bank tributaries export significantly less pre-aged material. GDGT distributions provide further evidence for seasonal and inter-annual variability in soil provenance. The cyclization of branched tetraethers and the GDGT-0 to crenarchaeol ratio are positively correlated with discharge (r ≥ 0.70; p-value ≤ 4.3 × 10− 5) due to the incorporation of swamp-forest soils when discharge from right-bank tributaries located in the northern hemisphere is high. Both metrics reach record lows during 2013, supporting our interpretation of increased left-bank contribution at this time. We conclude that hydrologic variability is a major control of POM provenance in the Congo River Basin and that tropical wetlands can be a significant POM source despite their small geographic coverage

    Cyclic cycle systems of the complete multipartite graph

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    In this paper, we study the existence problem for cyclic ℓ\ell-cycle decompositions of the graph Km[n]K_m[n], the complete multipartite graph with mm parts of size nn, and give necessary and sufficient conditions for their existence in the case that 2ℓ∣(m−1)n2\ell \mid (m-1)n

    Technical note : an inverse method to relate organic carbon reactivity to isotope composition from serial oxidation

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biogeosciences 14 (2017): 5099-5114, doi:10.5194/bg-14-5099-2017.Serial oxidation coupled with stable carbon and radiocarbon analysis of sequentially evolved CO2 is a promising method to characterize the relationship between organic carbon (OC) chemical composition, source, and residence time in the environment. However, observed decay profiles depend on experimental conditions and oxidation pathway. It is therefore necessary to properly assess serial oxidation kinetics before utilizing decay profiles as a measure of OC reactivity. We present a regularized inverse method to estimate the distribution of OC activation energy (E), a proxy for bond strength, using serial oxidation. Here, we apply this method to ramped temperature pyrolysis or oxidation (RPO) analysis but note that this approach is broadly applicable to any serial oxidation technique. RPO analysis directly compares thermal reactivity to isotope composition by determining the E range for OC decaying within each temperature interval over which CO2 is collected. By analyzing a decarbonated test sample at multiple masses and oven ramp rates, we show that OC decay during RPO analysis follows a superposition of parallel first-order kinetics and that resulting E distributions are independent of experimental conditions. We therefore propose the E distribution as a novel proxy to describe OC thermal reactivity and suggest that E vs. isotope relationships can provide new insight into the compositional controls on OC source and residence time.This research was supported by the NSF Graduate Research Fellowship Program grant no. 2012126152 (Jordon D. Hemingway), NASA Astrobiology grant no. NNA13AA90A and NSF grant no. EAR-1338810 (Daniel H. Rothman), and the WHOI Independent Study Award (Valier V. Galy)

    Structure and functional motifs of GCR1, the only plant protein with a GPCR fold?

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    Whether GPCRs exist in plants is a fundamental biological question. Interest in deorphanizing new G protein coupled receptors (GPCRs), arises because of their importance in signaling. Within plants, this is controversial as genome analysis has identified 56 putative GPCRs, including GCR1 which is reportedly a remote homologue to class A, B and E GPCRs. Of these, GCR2, is not a GPCR; more recently it has been proposed that none are, not even GCR1. We have addressed this disparity between genome analysis and biological evidence through a structural bioinformatics study, involving fold recognition methods, from which only GCR1 emerges as a strong candidate. To further probe GCR1, we have developed a novel helix alignment method, which has been benchmarked against the the class A – class B - class F GPCR alignments. In addition, we have presented a mutually consistent set of alignments of GCR1 homologues to class A, class B and class F GPCRs, and shown that GCR1 is closer to class A and /or class B GPCRs than class A, class B or class F GPCRs are to each other. To further probe GCR1, we have aligned transmembrane helix 3 of GCR1 to each of the 6 GPCR classes. Variability comparisons provide additional evidence that GCR1 homologues have the GPCR fold. From the alignments and a GCR1 comparative model we have identified motifs that are common to GCR1, class A, B and E GPCRs. We discuss the possibilities that emerge from this controversial evidence that GCR1 has a GPCR fol

    Predicting Amount of Compensatory Gain

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    In North American beef production systems, the entire spectrum of restriction and compensation is found. The area of compensatory gain is complex and not well understood, but critically important to the economics of cattle feeding. Several compensatory gain studies from the University of Nebraska have been compiled. The range in compensation observed with cattle grazing season-long is 19-88 percent with a mean of 53 percent. From these grazing studies, days of restriction appear to be related to percentage compensation. In the feedlot, even relatively short restrictions trigger compensatory gain; however, feed efficiency response to compensatory gain i

    A Comparison of Synovex ONE® Alone to Synovex Choice® Followed by Synovex Plus® as Implant Strategies for Finishing Heifers

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    A commercial feedlot study utilizing 1,737 crossbred heifers (initial BW 690 lb) compared the effect of two implant strategies [Synovex ONE Feedlot (day 0) or Synovex Choice (day 0) followed by Synovex Plus (day 95)] on performance and carcass characteristics. No differences were observed in carcass weight, final body weight, or gain, but heifers implanted with Synovex ONE Feedlot had slightly greater feed conversion and greater intake than heifers implanted using Synovex Choice/Synovex Plus. Heifers implanted with Synovex Choice/Synovex Plus had lower marbling score and yield grade, higher dressing percentage, and greater loin muscle area compared to heifers implanted with Synovex ONE Feedlot. Cattle implanted with Synovex ONE Feedlot showed a tendency for better quality grading compared to heifers implanted with Synovex Choice/Synovex Plus. These data suggest that implanting heifers with Synovex ONE Feedlot gives comparable growth to heifers implanted with Synovex Choice followed by Synovex Plus, with some changes in fatness when fed equal days
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