Enhancement of Foliar Penetration and Herbicide Activity by Oils

To learn more about oils and how they affect post-emergence spray applications of herbicides, two major problem areas were investigated. The first dealt with specific physical and chemical properties of oils as they are associated with phytotoxicity and enhancement of herbicidal activity, while the second dealt with foliar penetration as a possible mechanism of enhancement. Simple correlation and multiple regression analyses were conducted for specific properties of mineral oils applied to green foxtail (Setaria verdis (L.) Beauv.) and grain sorghum (Sorghwn bicolor (L.) Moench. \u27Northrup King 133\u27) as 5% oil in water emulsions with and without 2.24 kg/ha of atrazine (2-chloro-4-(ethylamino)-6- (isopropylamino)-s-triazine). Simple correlations identified individual oil properties important in explaining dry weight variabilities, but these single properties generally accounted for only a small portion of the total dry weight variability. Analyzing several oil properties by multiple regression analyses accounted for 99% of the variability due both to phytotoxicity and herbicide enhancement. Each of several combinations of eight different oil properties accounted for most of the dry weight variability because the properties were not mutually exclusive. Those properties most highly associated with atrazine enhancement included distillation temperatures, pour point, viscosity, viscosity index, refractive index, and flash point. Phytotoxicity of oil alone was associated with increased aromatic contents and decreased unsulfonated residue values. These findings were slightly altered when natural (crop) oils were included with the mineral oils due to inherent differences in the properties of the two types of oils. Several oils used as 5% oil/water emulsions significantly increased the herbicidal activity of atrazine on foxtail and sorghum when compared to atrazine in water alone or with 0.1% surfactant. Penetration of 14C from atrazine and dicamba (3,6-dichloro-o-anisic acid) through astomatous leaf surfaces of Tradescantia (Tradescantia fluminesis Vell.) was increased by use of oil-water emulsion as compared to 0.1% surfactant solution. Most of the radioactivity was found below the treated leaves of Tradescantia plants 1 day after treatment but accumulation in the plant parts above treated leaves increased by the 6th day. 14C-labeled mineral oil likewise was found to penetrate and translocate in the Tradescantia plants. Uptake of 14C from the oil increased from 20 to 57% in the first 6 days after treatment. Little additional uptake was noted at 15 days. Measurements of CO2 uptake by sorghum revealed that photosynthesis was completely inhibited 1.5 hours after treatment with atrazine in oil-water emulsion. Maximum penetration of 14C-labeled herbicides through isolated astomatous cuticles of Prunus armeniaca L. (apricot) leaves occurred (a) at warm rather than cold temperatures, (b) when chloroform extraction was used to remove wax prior to treatment, (c) from the air side of the cuticle to the mesophyll side rather than in the reverse direction, and (d) when oil emulsions were used as the carrier in short treatment periods compared with 0.1% surfactant. Penetration of 14C from dicamba was more rapid than absorption of 14C from atrazine. Autoradiographic studies using isolated astomatous apricot cuticles showed that cuticle areas over veins were preferred sites of entry for 14C from oils in both pure and emulsified forms and for 14C from dicamba regardless of carrier type. No preferred sites of penetration were found in cuticle areas directly above an individual cell whether the underlying cell was in a vein or non-vein area of the leaf

Weed Control in Lawns and Other Turf

Guide to weed control in lawns and other turf discusses methods of weed control, time of application, calibration of sprayers, dry spreaders, control of common weeds, and cleaning the sprayer

Topology of non-linear structure in the 2dF Galaxy Redshift Survey

We study the evolution of non-linear structure as a function of scale in samples from the 2dF Galaxy Redshift Survey, constituting over 221 000 galaxies at a median redshift of z=0.11. The two flux-limited galaxy samples, located near the southern galactic pole and the galactic equator, are smoothed with Gaussian filters of width ranging from 5 to 8 Mpc/h to produce a continuous galaxy density field. The topological genus statistic is used to measure the relative abundance of overdense clusters to void regions at each scale; these results are compared to the predictions of analytic theory, in the form of the genus statistic for i) the linear regime case of a Gaussian random field; and ii) a first-order perturbative expansion of the weakly non-linear evolved field. The measurements demonstrate a statistically significant detection of an asymmetry in the genus statistic between regions corresponding to low- and high-density volumes of the universe. We attribute the asymmetry to the non-linear effects of gravitational evolution and biased galaxy formation, and demonstrate that these effects evolve as a function of scale. We find that neither analytic prescription satisfactorily reproduces the measurements, though the weakly non-linear theory yields substantially better results in some cases, and we discuss the potential explanations for this result.Comment: 13 pages, matching proof to be published in MNRAS; new version adds reference and corrects figure

Exploiting anthracene photodimerization within peptides : light induced sequence-selective DNA binding

Here we detail the first example of anthracene photodimerisation in peptides, and use it to trigger a selective biomolecular recognition event.</p

Clipping the Cosmos: The Bias and Bispectrum of Large Scale Structure

A large fraction of the information collected by cosmological surveys is simply discarded to avoid lengthscales which are difficult to model theoretically. We introduce a new technique which enables the extraction of useful information from the bispectrum of galaxies well beyond the conventional limits of perturbation theory. Our results strongly suggest that this method increases the range of scales where the relation between the bispectrum and power spectrum in tree-level perturbation theory may be applied, from k_max ~ 0.1 h/Mpc to ~ 0.7 h/Mpc. This leads to correspondingly large improvements in the determination of galaxy bias. Since the clipped matter power spectrum closely follows the linear power spectrum, there is the potential to use this technique to probe the growth rate of linear perturbations and confront theories of modified gravity with observation.Comment: 5 pages, 2 figures. To appear in Physical Review Letter

Building Strong for Tomorrow: Recommendations for the Organizational Design of the NOAA Climate Service

The U.S. Congress asked an expert panel of the National Academy of Public Administration to assist NOAA with a study and analysis of organizational options for a Climate Service within NOAA. Further, NOAA formally asked the Panel to provide an independent assessment of how NOAA should organize its climate capabilities and make recommendations for a Climate Service line office structure that would integrate NOAA's climate science and research with service delivery.Main FindingsThe Panel strongly supports the creation of a Climate Service to be established as a line office within NOAA.The Panel concluded that a NOAA Climate Service, properly configured and implemented, would be uniquely qualified to serve the public and private sectors as a lead federal agency for climate research and services, and to provide an ongoing accessible, authoritative clearinghouse for all federal science and services related to climate.The report also includes the Panel's observations and recommendations regarding the larger federal climate enterprise, key elements of support needed by the NOAA Climate Service and the importance to the new organization of a clear strategic plan and a comprehensive implementation plan. Additionally, the Panel offered observations about institutional change management in the federal sector, identified several management recommendations for implementation and addressed operational priorities and budget challenges

The XMM-Newton Wide field survey in the COSMOS field: redshift evolution of AGN bias and subdominant role of mergers in triggering moderate luminosity AGN at redshift up to 2.2

We present a study of the redshift evolution of the projected correlation function of 593 X-ray selected AGN with I_AB<23 and spectroscopic redshifts z<4, extracted from the 0.5-2 keV X-ray mosaic of the 2.13 deg^2 XMM-COSMOS survey. We introduce a method to estimate the average bias of the AGN sample and the mass of AGN hosting halos, solving the sample variance using the halo model and taking into account the growth of the structure over time. We find evidence of a redshift evolution of the bias factor for the total population of XMM-COSMOS AGN from b(z=0.92)=2.30 +/- 0.11 to b(z=1.94)=4.37 +/- 0.27 with an average mass of the hosting DM halos logM [h^-1 M_sun] ~ 13.12 +/- 0.12 that remains constant at all z < 2. Splitting our sample into broad optical lines AGN (BL), AGN without broad optical lines (NL) and X-ray unobscured and obscured AGN, we observe an increase of the bias with redshift in the range z=0.7-2.25 and z=0.6-1.5 which corresponds to a constant halo mass logM [h^-1 M_sun] ~ 13.28 +/- 0.07 and logM [h^-1 M_sun] ~ 13.00 +/- 0.06 for BL /X-ray unobscured AGN and NL/X-ray obscured AGN, respectively. The theoretical models which assume a quasar phase triggered by major mergers can not reproduce the high bias factors and DM halo masses found for X-ray selected BL AGN with L_BOL ~ 2e45 erg s^-1. Our work extends up to z ~ 2.2 the z <= 1 statement that, for moderate luminosity X-ray selected BL AGN, the contribution from major mergers is outnumbered by other processes, possibly secular such as tidal disruptions or disk instabilities.Comment: 16 emulateapj pages, 18 figures and 3 tables. Accepted for the publication in The Astrophysical Journa