TB85: A New Potato Scab Problem in Maine

The scientific literature is filled with conflicting reports on the development of the common scab disease of potatoes and its causal organism. One unresolved question is soil reaction, once thought to be the answer in controlling this disease. Scientific studies an d practical experience over a long period had shown that acid soils having a pH of approximately 5.3 or below usually did not support common scab development, though sporadic and unexplained reports of disease occurrence in these soils were observed. In the late 1950s, however, such reports became more frequent in Maine and before the mid-1960s, losses relate d to scabb y potatoes growing in acid soils were common. Throughout this period overall crop losses from the disease were minimal even though individual growers sometimes lost a large par t of their crop. During the dry 1970 growing season, however, a disease survey estimated that up to 5% of the Maine crop was scabby. Studies of this new form of scab and observations on its development within the state are reported herein.https://digitalcommons.library.umaine.edu/aes_techbulletin/1114/thumbnail.jp

A catalogue of faint local radio AGN and the properties of their host galaxies

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We present a catalogue of 2210 local ( z < 0.1) galaxies that contain faint active galactic nuclei (AGN). We select these objects by identifying galaxies that exhibit a significant excess in their radio luminosities, compared to what is expected from the observed levels of star formation activity in these systems. This is achieved by comparing the optical (spectroscopic) star formation rate (SFR) to the 1.4 GHz luminosity measured from the Faint Images of the Radio Sky at Twenty centimeters survey. The majority of the AGN identified in this study are fainter than those in previous work, such as in the Best and Heckman (2012) catalogue. We show that these faint AGN make a non-negligible contribution to the radio luminosity function at low luminosities (below 1022.5 W Hz−1), and host ∼13 per cent of the local radio luminosity budget. Their host galaxies are predominantly high stellar-mass systems (with a median stellar mass of 1011 M⊙), are found across a range of environments (but typically in denser environments than star-forming galaxies) and have early-type morphologies. This study demonstrates a general technique to identify AGN in galaxy populations where reliable optical SFRs can be extracted using spectro-photometry and where radio data are also available so that a radio excess can be measured. Our results also demonstrate that it is unsafe to infer SFRs from radio emission alone, even if bright AGN have been excluded from a sample, since there is a significant population of faint radio AGN that may contaminate the radio-derived SFRs.Peer reviewedFinal Published versio

Controlled Radical Polymerization of Vinyl Acetate Mediated by a Bis(imino)pyridine Vanadium Complex

Source type: Prin

Mechanism Of N(5)-ethyl-flavinium Cation Formation Upon Electrochemical Oxidation Of N(5)-ethyl-4a-hydroxyflavin Pseudobase

We investigated the oxidation behavior of 5-ethyl-4a-hydroxy-3-methy1-4a,5-dihydrolumitlavin (pseudobase Et-FlH) in acetonitrile with the aim of determining if the two-electron oxidized Et-FlOH(2+) undergoes a release of hydroxyl cation and the production of 5-ethyl-3methyllumiflavinium cation (Et-Fl(+)). The focus of this work is to investigate the possibility of using Et-FlOH as a catalyst for water oxidation. The cyclic voltammetry demonstrates that Et-FlOH exhibits two one-electron oxidation potentials at +0.95 and +1.4 V versus normal hydrogen electrode (NHE), with the second oxidation potential being irreversible. The production of Et-FY\u27 is observed in the cyclic voltammetry of Et-FlOH and has been previously assigned to the release of OH(+) from the two-electron oxidized Et-FlOH(2+). The results of our study show that this is not the case: (i) we performed bulk electrolysis of the electrolyte solution at +2 V and then added Et-FlOH to the electrolyzed solution. We found that Et-Fr is produced from this solution, even though Et-FlOH itself was not oxidized; (ii) reactions of Et-FlOH with chemical oxidants (eerie ammonium nitrate, nitrosyl tetrafluoroborate, and tetrabutylammonium persulfate) demonstrate. that Et-Fl(+) production occurs only in the presence of strong Lewis acids, such as Ce(4+) and NO(+) ions. On the basis of these results, we propose that the production of Et-Fl+ in the electrochemistry of Et-FlOH(-1) occurs because of the shift in the Et-FlOH/Et-Fl+ acid base equilibrium in the presence of protons released during anodic oxidation. We identified two sources of protons: (i) oxidation of traces of water present in the acetonitrile releases oxygen and protons and (ii) two-electron oxidized Et-FlOH(2+) releases protons located on the N(5)-alkyl chain. The release of protons from Et-FlOH(2+) was confirmed by cyclic voltammetry of Et-FlOH in the presence of pyridine as a base. The first oxidation peak of Et-FlOH at +0.95 V is reversible in the absence of pyridine. The addition of pyridine leads to the shift of the oxidation potential to a less positive value, which is consistent with a proton-coupled electron transfer (PCET). Furthermore, the anodic current increases, and the cathodic peak becomes irreversible, giving rise to two additional reduction peaks at -0.2 and -1 V. The same reduction peaks were observed in the high scan rate cyclic voltammogram of Et-FlOH in the absence of pyridine, implying that the release of protons indeed occurs from Et-FlOH(2+). To determine which functional group of Et-FlOH(center dot+) is the source of protons, we performed DFT calculations at the B3LYP/6-311++G level of theory for a reaction of Et-FlOH(center dot+). with pyridine and identified two proton sources: (i) the \u3eN-CH(2)(-) group of the N(5) alkyl chain and (ii) the OH group in the 4a-position of the radical cation. Because the appearance of new reduction peaks at 0.2 and 1.0 V occurs in the model compound that lacks OH protons (Et-FlOMe), we conclude that the proton removal occurs predominantly from the \u3eN-CH(2)- moiety

Electronic Properties Of N(5)-ethyl Flavinium Ion

We investigated the electronic properties of N(5)-ethyl flavinium perchlorate (Et-Fl(+)) and compared them to those of its parent compound, 3-methyllumiflavin (Fl). Absorption and fluorescence spectra of Fl and Et-Fl(+) exhibit similar spectral features, but the absorption energy of Et-Fl(+) is substantially lower than that of Fl. We calculated the absorption signatures of Fl and Et-Fl(+) using time-dependent density functional theory (TD-DFT) methods and found that the main absorption bands of Fl and Et-Fl(+) are (pi,pi*) transitions for the S(1) and S(3) excited states. Furthermore, calculations predict that the S(2) state has (n,pi*) character. Using cyclic voltammetry and a simplistic consideration of the orbital energies, we compared the HOMO/LUMO energies of Fl and Et-Fl(+). We found that both HOMO and LUMO orbitals of Et-Fl(+) are stabilized relative to those in Fl, although the stabilization of the LUMO level was more pronounced. Visible and mid-IR pump-probe experiments demonstrate that Et-Fl(+) exhibits a shorter excited-state lifetime (590 ps) relative to that of Fl (several nanoseconds), possibly due to faster thermal deactivation in Et-Fl(+), as dictated by the energy gap law. Furthermore, we observed a fast (23-30 ps) S(2) -\u3e S(0) internal conversion in transient absorption spectra of both Fl and Et-Fl(+) in experiments that utilized pump excitations with higher energy

Newly detected ozone-depleting substances in the atmosphere

Ozone-depleting substances emitted through human activitiescause large-scale damage to the stratospheric ozone layer, and influence global climate. Consequently, the production of many of these substances has been phased out; prominent examples are the chlorofluorocarbons (CFCs), and their intermediate replacements, the hydrochlorofluorocarbons (HCFCs). So far, seven types of CFC and six types of HCFC have been shown to contribute to stratospheric ozone destruction 1,2. Here, we report the detection and quantification of a further three CFCs and one HCFC. We analysed the composition of unpolluted air samples collected in Tasmania between 1978 and 2012, and extracted from deep firn snow in Greenland in 2008, using gas chromatography with mass spectrometric detection. Using the firn data, we show that all four compounds started to emerge in the atmosphere in the 1960s. Two of the compounds continue to accumulate in the atmosphere. We estimate that, before 2012, emissions of all four compounds combined amounted to more than 74,000 tonnes. This is small compared with peak emissions of other CFCs in the 1980s of more than one million tonnes each year 2. However, the reported emissions are clearly contrary to the intentions behind the Montreal Protocol, and raise questions about the sources of these gases

Identifying and Prioritizing Greater Sage-Grouse Nesting and Brood-Rearing Habitat for Conservation in Human-Modified Landscapes

BACKGROUND: Balancing animal conservation and human use of the landscape is an ongoing scientific and practical challenge throughout the world. We investigated reproductive success in female greater sage-grouse (Centrocercus urophasianus) relative to seasonal patterns of resource selection, with the larger goal of developing a spatially-explicit framework for managing human activity and sage-grouse conservation at the landscape level. METHODOLOGY/PRINCIPAL FINDINGS: We integrated field-observation, Global Positioning Systems telemetry, and statistical modeling to quantify the spatial pattern of occurrence and risk during nesting and brood-rearing. We linked occurrence and risk models to provide spatially-explicit indices of habitat-performance relationships. As part of the analysis, we offer novel biological information on resource selection during egg-laying, incubation, and night. The spatial pattern of occurrence during all reproductive phases was driven largely by selection or avoidance of terrain features and vegetation, with little variation explained by anthropogenic features. Specifically, sage-grouse consistently avoided rough terrain, selected for moderate shrub cover at the patch level (within 90 m(2)), and selected for mesic habitat in mid and late brood-rearing phases. In contrast, risk of nest and brood failure was structured by proximity to anthropogenic features including natural gas wells and human-created mesic areas, as well as vegetation features such as shrub cover. CONCLUSIONS/SIGNIFICANCE: Risk in this and perhaps other human-modified landscapes is a top-down (i.e., human-mediated) process that would most effectively be minimized by developing a better understanding of specific mechanisms (e.g., predator subsidization) driving observed patterns, and using habitat-performance indices such as those developed herein for spatially-explicit guidance of conservation intervention. Working under the hypothesis that industrial activity structures risk by enhancing predator abundance or effectiveness, we offer specific recommendations for maintaining high-performance habitat and reducing low-performance habitat, particularly relative to the nesting phase, by managing key high-risk anthropogenic features such as industrial infrastructure and water developments

Software for the frontiers of quantum chemistry:An overview of developments in the Q-Chem 5 package

This article summarizes technical advances contained in the fifth major release of the Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library of exchange–correlation functionals, along with a suite of correlated many-body methods, continues to be a hallmark of the Q-Chem software. The many-body methods include novel variants of both coupled-cluster and configuration-interaction approaches along with methods based on the algebraic diagrammatic construction and variational reduced density-matrix methods. Methods highlighted in Q-Chem 5 include a suite of tools for modeling core-level spectroscopy, methods for describing metastable resonances, methods for computing vibronic spectra, the nuclear–electronic orbital method, and several different energy decomposition analysis techniques. High-performance capabilities including multithreaded parallelism and support for calculations on graphics processing units are described. Q-Chem boasts a community of well over 100 active academic developers, and the continuing evolution of the software is supported by an “open teamware” model and an increasingly modular design

Upgrade of Biomass-Derived Levulinic Acid via Ru/C-Catalyzed Hydrogenation to γ‑Valerolactone in Aqueous−Organic−Ionic Liquids Multiphase Systems

A liquid triphase system made by an aqueous phase, an organic phase, and an ionic liquid was designed and applied to the catalytic hydrogenation/dehydration of biomass-derived levulinic acid to γ-valerolactone. This paper demonstrates that, by operating at 100−150 °C and 35 atm of H2, both in the presence of Ru/C or of a homogeneous Ru precursor, the use of the triphase system designed to match the investigated reaction allows the following: (1) to obtain up to quantitative conversions and 100% selectivity toward the desired product; (2) to recover the product by simple phase separation; and (3) to preserve the catalyst activity for in situ recycles without loss of metal. Globally the investigated reaction proves the concept that a cradle-to-grave approach to the design of a catalytic reaction system can improve the global sustainability of a chemical transformation by improving efficiency, product isolation, and catalyst recycle