Growth and Fecundity of Several Weed Species in Corn and Soybean

Do weeds that emerge later in the season justify additional control costs\u27? If crop yield is not reduced or few or no seeds arc added to the soil seed hank, then no control may he needed. Eight weed species were sown in corn (Zea mays L.) and soybean I Glycine max (L.) Mcrr.l (i) before crop emergence, (ii) at crop emergence, (iii) at V-1, and (iv) at V-2 stages of crop growth in 2002 and 2003. Weed seed was sown close to the crop row and thinned to 1.3 plants m 2• Weed growth and fecundity were influenced by species, time of planting, and year. Only barnyarclgrass (Echinochloa crus-galli L.), rcclroot pigwced (Amaranthus retniflexus L.), and vclvetlcaf (Abutilon theophrasti L.) survived to produce seed. Plants from the pre-emergence seeding had the largest canopy and produced the most seeds. Harnyardgrass had maximum canopy cover in early .July in corn and late .Inly in soybean hut only produced seed in corn. Rcclroot pigweecl and vclvctleaf had maximum canopy cover in late August or midSeptember, and some plants from most seeding elates survived and produced seed in both corn and soybean. However, plants that grew from seed sown at V-1 and V-2 crnp grnwth stages did not reduce yield or biomass of adjacent crop plants, had low fecundity, and may not warrant treatment. Control may be necessary, however, to prevent yield losses if weeds arc present at high densities or to prevent establishment of uncommon species

Photocatalytic properties of tin oxide and antimony-doped tin oxide nanoparticles

For the first time it is shown that N-doped SnO2 nanoparticles photocatalyze directly the polymerization of the C=C bonds of (meth)acrylates under visible light illumination. These radical polymerizations also occur when these particles are doped with Sb and when the surfaces of these particles are grafted with methacrylate (MPS) groups. During irradiation with visible or UV light the position and/or intensity of the plasmon band absorption of these nanoparticles are always changed, suggesting that the polymerization starts by the transfer of an electron from the conduction band of the particle to the (meth)acrylate C=C bond. By using illumination wavelengths with a very narrow band width we determined the influence of the incident wavelength of light, the Sb- and N-doping, and the methacrylate (MPS) surface grafting on the quantum efficiencies for the initiating radical formation (F) and on the polymer and particle network formation. The results are explained by describing the effects of Sb-doping, N-doping, and/or methacrylate surface grafting on the band gaps, energy level distributions, and surface group reactivities of these nanoparticles. N-doped (MPS grafted) SnO2 (Sb = 0%) nanoparticles are new attractive photocatalysts under visible as well as UV illumination

Live‐cell super‐resolution imaging of actin using LifeAct‐14 with a PAINT‐based approach

We present direct‐LIVE‐PAINT, an easy‐to‐implement approach for the nanoscopic imaging of protein structures in live cells using labeled binding peptides. We demonstrate the feasibility of direct‐LIVE‐PAINT with an actin‐binding peptide fused to EGFP, the location of which can be accurately determined as it transiently binds to actin filaments. We show that direct‐LIVE‐PAINT can be used to image actin structures below the diffraction‐limit of light and have used it to observe the dynamic nature of actin in live cells. We envisage a similar approach could be applied to imaging other proteins within live mammalian cells

DNaseI Hypersensitivity and Ultraconservation Reveal Novel, Interdependent Long-Range Enhancers at the Complex Pax6 Cis-Regulatory Region

The PAX6 gene plays a crucial role in development of the eye, brain, olfactory system and endocrine pancreas. Consistent with its pleiotropic role the gene exhibits a complex developmental expression pattern which is subject to strict spatial, temporal and quantitative regulation. Control of expression depends on a large array of cis-elements residing in an extended genomic domain around the coding region of the gene. The minimal essential region required for proper regulation of this complex locus has been defined through analysis of human aniridia-associated breakpoints and YAC transgenic rescue studies of the mouse smalleye mutant. We have carried out a systematic DNase I hypersensitive site (HS) analysis across 200 kb of this critical region of mouse chromosome 2E3 to identify putative regulatory elements. Mapping the identified HSs onto a percent identity plot (PIP) shows many HSs correspond to recognisable genomic features such as evolutionarily conserved sequences, CpG islands and retrotransposon derived repeats. We then focussed on a region previously shown to contain essential long range cis-regulatory information, the Pax6 downstream regulatory region (DRR), allowing comparison of mouse HS data with previous human HS data for this region. Reporter transgenic mice for two of the HS sites, HS5 and HS6, show that they function as tissue specific regulatory elements. In addition we have characterised enhancer activity of an ultra-conserved cis-regulatory region located near Pax6, termed E60. All three cis-elements exhibit multiple spatio-temporal activities in the embryo that overlap between themselves and other elements in the locus. Using a deletion set of YAC reporter transgenic mice we demonstrate functional interdependence of the elements. Finally, we use the HS6 enhancer as a marker for the migration of precerebellar neuro-epithelium cells to the hindbrain precerebellar nuclei along the posterior and anterior extramural streams allowing visualisation of migratory defects in both pathways in Pax6(Sey/Sey) mice

Segmental bronchial provocation induces nasal inflammation in allergic rhinitis patients

Allergic rhinitis and asthma often coexist and share a genetic background. Pathophysiologic connections between the nose and lungs are still not entirely understood. This study was undertaken to compare allergic inflammation and clinical findings in the upper and lower airways after segmental bronchial provocation (SBP) in nonasthmatic allergic rhinitis patients. Eight nonasthmatic, grass pollen-sensitive patients with allergic rhinitis and eight healthy controls were included. Bronchial biopsies and blood samples were taken before (T(0)) and 24 h (T(24)) after SBP. Nasal biopsies were obtained at T(0), 1 h after SBP (T(1)), and T(24). Immunohistochemical staining was performed for eosinophils (BMK13), interleukin (IL)-5, and eotaxin. The number of eosinophils increased in the challenged and unchallenged bronchial mucosa (p < 0.05) and in the blood (p = 0.03) of atopic subjects at T(24). We detected an increase of BMK13-positive and eotaxin-positive cells in the nasal lamina propria and enhanced expression of IL-5 in the nasal epitheliu

Dielectric quantification of conductivity limitations due to nanofiller size in conductive powders and nanocomposites

Conducting submicron particles are well-suited as filler particles in non-conducting polymer matrices to obtain a conducting composite with a low percolation threshold. Going to nanometer-sized filler particles imposes a restriction to the conductivity of the composite, due to the reduction of the density of states involved in the hopping process between the particles, compared to its value within the crystallites. We show how those microscopic parameters that govern the charge-transport processes across many decades of length scales, can accurately and consistently be determined by a range of dielectric-spectroscopy techniques from a few Hz to infrared frequencies. The method, which is suited for a variety of systems with restricted geometries, is applied to densely packed 7-nm-sized tin-oxide crystalline particles with various degree of antimony doping and the quantitative results unambiguously show the role of the nanocrystal charging energy in limiting the hopping process.Comment: 6 pages, 4 figure

Dasineura rubiformis (Diptera: Cecidomyiidae), a new biological control agent for Acacia mearnsii in South Africa

Acecidomyiid midge, Dasineura rubiformis, is the most recent addition to the suite of biological control agents that have been deployed in South Africa against invasive Australian Acacia species. This insect is associated with Acacia mearnsii (black wattle), which is extremely invasive, but also an important agro-forestry species, in South Africa. It induces development of galls in the flowers of A. mearnsii, thereby preventing pod development and reducing the reproductive capacity of the plants. The useful attributes of this economically important plant species should not be affected by the introduction of D. rubiformis. The midge is established in the vicinity of Stellenbosch, where it is increasing in abundance. Studies have been initiated to (i) evaluate the performance of the midge; (ii) confirm that galling does not cause a reduction in vegetative growth of A. mearnsii; and (iii) determine the potential effectiveness of D. rubiformis as a biological control agent of A. mearnsii. All indications are that the insect has the potential to become an excellent seed-reducing biological control agent of A. mearnsii

Dielectric quantification of conductivity limitations due to nanofiller size in conductive powders and nanocomposites,” Physical Review B,

Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher&apos;s website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the &quot;Taverne&quot; license above, please follow below link for the End User Agreement: www.tue.nl/taverne Take down policy If you believe that this document breaches copyright please contact us at: [email protected] providing details and we will investigate your claim. Conducting submicron particles are well suited as filler particles in nonconducting polymer matrices to obtain a conducting composite with a low percolation threshold. Going to nanometer-sized filler particles imposes a restriction to the conductivity of the composite, due to the reduction of the density of states involved in the hopping process between the particles, compared to its value within the crystallites. We show how those microscopic parameters that govern the charge-transport processes across many decades of length scales can accurately and consistently be determined by a range of dielectric-spectroscopy techniques from a few hertz to infrared frequencies. The method, which is suited for a variety of systems with restricted geometries, is applied to densely packed 7-nm-sized tin oxide crystalline particles with various degree of antimony doping and the quantitative results unambiguously show the role of the nanocrystal charging energy in limiting the hopping process

Developments and prospects for biological control of Prosopis (Leguminosae) in South Africa

South Africa was the first country to deploy biological control (biocontrol) against invasive Prosopis populations. Developments in this regard have been ongoing, and have been reviewed, at approximately 10-year intervals, since 1991. This review spans the period 2011-2020, a timespan globally characterised by increased awareness of the impacts of invasive Prosopis populations, and recognition of the need for improved management. Concerted international collaboration has resulted in enhanced clarity on phylogenetic relationships within the Leguminosae and the phylogenetic placement of Prosopis. These advances have improved the framework for interpreting the host range of potential agents and for evaluating risk. At the outset of the biocontrol programme, in the 1980s, only agents that consumed mature seeds were considered. The intention was to reduce the invasiveness of Prosopis while simultaneously retaining it as a usable resource. The programme was subsequently expanded to investigate agents that prevent pod set or maturation of seed. More recently, potential agents that damage the vegetative growth of the plants have been included in response to recognition in South Africa, that there is no other route to successful management of Prosopis. There is a wealth of largely unexplored potential in this regard