31,887 research outputs found
The First 30 Years of Shiga Toxin–Producing Escherichia coli in Cattle Production: Preharvest Intervention Strategies
No full textShiga toxin–producing Escherichia coli (STEC) are the fourth leading cause of bacterialderived
foodborne illness in the United States (CDC, 2016). Cattle are recognized as a natural
reservoir for STEC, including E. coli O157:H7 (Karmali et al., 2010), and historically, most
STEC-induced foodborne illnesses are associated with handling/consuming contaminated or
undercooked beef products (White et al., 2016). In 1994, the Food Safety Inspection Service
(FSIS) declared E. coli O157:H7 an adulterant in raw ground beef, and in 2011, additional
STEC serogroups were declared adulterants (FSIS, 2011). Initial postharvest control measures
implemented by the cattle industry to combat STEC were successful; however, to further reduce
the incidence of human illness and ensure a safe and wholesome food supply, research into
preharvest pathogen reduction and intervention strategies has been pursued (Oliver et al., 2008;
Sargeant et al., 2007). Implementation of pathogen-reduction strategies in live cattle has the
potential to reduce human illnesses (Rotariu et al., 2012; Smith et al., 2012) by (1) reducing the
number of pathogens entering processing plant on/in an animal; (2) reducing horizontal pathogen
transfer from infected animals; (3) lowering the pathogenic bacterial burden in the environment
and wastewater streams; and (4) reducing the risk to those in direct contact with animals.
The current preharvest intervention strategies to reduce the incidence of human STEC illnesses
acquired from beef products have been reviewed (Callaway et al., 2013a,b) but will be briefly
highlighted and updated herein. A sound management program (described in our previous
chapter) in conjunction with preharvest intervention strategies will provide a farm-to-fork
approach to reduce the incidence of STEC throughout a cattle operation
Ordering of organic molecules on templated surfaces
No full textThis thesis describes the controlled growth of molecular nanostructures using modified metallic and semiconductor surfaces. The Ag/Si(lll)-(root3 x root3),the Sn/Cu(100) surface alloy system and the Bi/Si(100) nanolines and (2xn) surfaces were all investigated as suitable substrates for the controlled growth of pentacene, (C22H14) or trimesic acid, (C6H3(COOH)3) organic molecules. The following techniques were used in this study; Scanning Tunnelling Microscopy (STM), Low Energy Electron Diffraction (LEED), Normal Incident X-Ray Standing Waves (NIXSW) and Temperature Programmed Desorption (TPD).
The room temperature growth and ordering of trimesic acid on the AgfSi(ll1)-(root3 x root3) surface was investigated. An oblique unit cell was determined and a model proposed for the highly ordered close-packed domains.
The discovery of a new submonolayer phase on Sn/Cu(100) and the re-examined known phase are discussed. New models for these reconstructions are proposed. Adsorption of trimesic acid at room temperature on the clean substrate the lowest Sn coverage phase were studied. Two new Sn coverage dependent structures were discovered and bonding schemes in upright and flat orientations are discussed.
BifSi(100)-(2xn) surface was exploited as a template for the ordered growth of pentacene, which exhibited orientation specific adsorption. The Bi/Si(100)-(2xn) single domain surface created on vicinal silicon was used to test the suitable of Daresbury 4.2 beamline for NIXSW Imaging experiments and the quality of the results are discussed
Portrait of William M. Chase
No full textPostal que reproduce una pintura del año 1902 de John Singer Sargent. Representa a William Merritt Chase, profesor de arte y admirador del trabajo de Sargent. Lo representa como pintor, con los útiles propios como el pincel o la paleta. Aparece vestido con traje de chaqueta con gafas, como si se tratase de un caballero. https://www.metmuseum.org/art/collection/search/12471Al pie de la postal aparece el siguiente texto: The Metropolitan Museum of Ar
Combination of Advanced Optical Modelling with Electrical Simulation for Performance Evaluation of Practical 4-terminal Perovskite/c-Si Tandem Modules
No full textAbstractThe perovskite solar cell is considered a promising candidate as the top cell for high-efficiency tandem devices with crystalline silicon (c-Si) bottom cells, contributing to the cost reduction of photovoltaic energy. In this contribution, a simulation method, involving optical and electrical modelling, is established to calculate the performance of 4-terminal (4T) perovskite/c-Si tandem devices on a mini-module level. Optical and electrical characterization of perovskite and c-Si solar cells are carried out to verify the simulation parameters. With our method, the influence of transparent conductive oxide (TCO) layer thickness of perovskite top cells on the performance of tandem mini-modules is investigated in case of both tin-doped indium oxide (ITO) and hydrogen-doped indium oxide (IO:H). The investigation shows that optimization of TCO layer thickness and replacement of conventional ITO with highly transparent IO:H can lead to an absolute efficiency increase of about 1%. Finally, a practical assessment of the efficiency potential for the 4T perovskite/c-Si tandem mini-module is carried out, indicating that with a relatively simple 4T tandem module structure the efficiency of a single-junction c-Si mini-module (19.3%) can be improved by absolute 4.5%
Parasitic copepods from Egyptian Red Sea fishes: Bomolochidae Claus, 1875
No full text© The Author(s) 2015
Open Access - This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The attached file is the published version of the article.NHM Repositor
High-efficiency black IBC c-Si solar cells with poly-Si as carrier-selective passivating contacts
No full textIn this work, we present the application of poly-Si carrier-selective passivating contacts (CSPCs) as both polarities in interdigitated back-contacted (IBC) solar cell architectures. We compared two approaches to form a gap between the back-surface field (BSF) and emitter fingers. It is proved that the gaps prepared by both approaches are efficient in preventing carriers’ recombination. To minimize the reflection losses, we developed a novel modulated surface texturing (MST) structure as anti-reflection coating (ARC). It is obtained by superposing a nano-textured SiO2 layer on the conventional micro-textured pyramids, which are passivated with a-Si:H / SiNx:H layers. This approach decouples the light harvesting from the Si surface passivation, which potentially results in the highest possible optical and electrical performances of the solar cells. The reflectance (R) of the MST-ARC is very close to that of the high-aspect ratio nano-structured silicon (black-Silicon), achieving R < 1% between 450 and 1000 nm. The J0 of MST-ARC passivated Si surface (6.3 fA/cm2) is the same as that of standard a-Si:H/SiNx:H layers passivated pyramidally-textured Si surface. By applying this novel MST-ARC in our IBC solar cell, the highest JSC observed in a device is 42.2 mA/cm2 with a VOC as high as 701 mV. A spectral response enhancement in case of the MST-ARC cell is observed over the whole wavelength range with respect to the cell with standard SiNx:H ARC. The highest efficiency achieved in this work is 23.0%, with the potential to reach 24.0% in short term by using more conductive metal fingers.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Photovoltaic Materials and DevicesElectrical Sustainable Energ
Strategie d'impresa: l'imperativo della responsabilità sociale
No full textIl capitolo si focalizza sulle relazioni tra Operations Management e Sostenibilità. Propone un framework per verificare la compatibilità tra sostenibilità economia, ambientale e sociale e le diverse fasi del ciclo di vita di un prodotto: dalla progettazione al riuso nell'ottica dell'economia circolare
Morphological character evolution of Amorphophallus (Araceae) based on a combined phylogenetic analysis of trnL, rbcL, and LEAFY second intron sequences
No full textSequences of three different genes in 69 taxa of Amorphophallus were combined to reconstruct the molecular phylogeny of this species-rich Aroid genus. The data set was analyzed by three different methods, Maximum Parsimony, Maximum Likelihood and Bayesian analysis, producing slightly different tree topologies. Three major clades identified in all analyses reflect the biogeographical distribution of Amorphophallus. Some clades were supported by morphological characters such as sessile/nonsessile stigma, pollen opening mechanism, shape of the main segments of the lamina, growth cycle, and berry colour. When optimised, a nonsessile stigma may have evolved from a sessile one with several reversals. Pollen opening by connective rupturing evolved from pollen opening by pores. Unequally shaped segments of the lamina evolved from equally shaped segments. Simultaneously existing leaf and inflorescences evolved from alternating leaves and inflorescences. Blue, purple, green, and yellow berries evolved from red/orange/white ones
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