Iowa Cooperative Fertilizer Retail Outlets: Farmers' Attitudes and Perceptions

Based on a sample of Iowa farmers, attributes of fertilizer retail dealers are evaluated. Honest management, making deliveries on time, relative size, willingness to negotiate price, and marketing grain are the most important attributes affecting a farmer's decision to patronize an independent or cooperative dealer. Cooperative outlets are generally in a strong competitive position. The study also shows much salient information can be generated by using such statistical methods as segmentation analysis, factor analysis, and the choice model approach.Fertilizer, supply cooperative, farmers' perception, dealer attributes, segmentation analysis, factor analysis, choice model, logit, Agribusiness,

Modification of the anisotropy and strength differential effect of extruded AZ31 by extrusion-shear

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in AIP Conference Proceedings 1960, 030008 (2018) and may be found at https://doi.org/10.1063/1.5034851.The extrusion of magnesium alloys results in a pronounced fiber texture in which the basal planes are mostly oriented parallel and the c-axes are oriented perpendicular to the extrusion direction. Due to this texture the Strength Differential Effect (SDE), which describes the strength difference between tensile and compression yield strength, and the elastic anisotropy in the sheet plane are obtained during extrusion. The objective of the investigation was to decrease the SDE and anisotropy through specifically influencing the microstructure and texture. To accomplish this objective, the forming processes extrusion (EX) and equal channel angular pressing (ECAP) were combined and integrated into one extrusion die. This combination is called extrusion-shear (ES). With an ES-die, billets of the magnesium alloy AZ31B were formed into a sheet with the thickness of 4 mm and the width of 70 mm. The angles of the used ECAP-applications in the ES-dies were set to 90° and 135°. The results show that the extrusion-shear process is able to decrease the anisotropy and SDE through transformation of the texture compared to conventional extrusion process. Also grain refinement could be observed. However, the outcomes seem to be very sensitive to the process parameters. Only by using the ES-die with an angle of 135° the desired effect could be accomplished

Application of Friction Shear Test for Constitutive Modeling Evaluation of Magnesium Alloy AZ31B at high Temperature

The experimental determination of the flow stress and its mathematical formulation are essential for the numerical simulation of metal forming processes. The hot compression test is widely used to analyze the flow stress evolution as function of temperature, strain and strain rate. The compression test is limited to a relative low strain (ε≤1) which is acceptable when the stress is minor influenced at higher strains. In the case of magnesium alloys the flow stress is strongly influenced by the strain even at high strain (ε>1). In this work the thermo-mechanical behavior of the magnesium alloy AZ31B was investigated to improve the constitutive modeling up to high strains. Experimental stress-strain curves obtained from hot compression tests at different temperatures (450 °C-550 °C) and strain rates (0.01 1/s – 10 1/s) were applied to construct conventional material models such as those proposed by Garofalo (Zener-Hollomon) and Hensel-Spittel. In addition, shear tests under sticking friction conditions were carried out at high temperature (400 °C-500 °C) and different shear speeds (0.1 mm/s - 10 mm/s). During this test, the thin contact subsurface of cylindrical specimens experiences a high plastic shear deformation, while the axial force and stroke are simultaneously measured. Furthermore, a new constitutive modeling approach was proposed, which combine the Zener-Hollomon model and the experimental result of the friction shear test to estimate the flow stress at low and high strain respectively. Numerical simulations of the friction shear test applying the conventional models as well as the new constitutive formulation are presented in this study

Identification and characterisation of Chlamydia psittaci Inc proteins and mechanistic elucidation of doxycycline-induced persistence of Chlamydia trachomatis

The obligate intracellular pathogens Chlamydia trachomatis and C. psittaci can infect humans, while C. psittaci also infect birds. During the intracellular infection, the bacteria replicate and develop inside of a membrane component, called inclusion. Chlamydia secrete proteins into the inclusion membrane, so called inclusion membrane proteins (Inc proteins). Inc proteins modify the inclusion and interact with host cell proteins. Dependent on species and even serovar, they cause different diseases with consequential damage if treatment fails. Patients infected with C. trachomatis serovar D are treated with the translation inhibitor doxycycline. Doxycycline induces a state in C. trachomatis serovar D, called persistence, which enables to persist the treatment and continue infection afterwards. This work identifies and characterises C. psittaci Inc proteins, and elucidates the mechanism of doxycycline-induced persistence of C. trachomatis serovar D. C. psittaci, as a zoonotic pathogen of birds and humans, was investigated according to host cellular interaction to decipher interspecies similarities and basics to understand the pathogens' capability to adapt to different hosts. A new method was established to study the interactions between Inc proteins and the host cell: split-Inc proteins. The split-Inc proteins are based on the enhanced green fluorescent protein eGFP, which replaces the membrane domain of Inc proteins. The integration of the N- and C-terminal cytosolic domains of an Inc protein enables mimicry of native interactions. The eGFP portion of split-Inc proteins allows the co-immunoprecipitation of protein interaction complexes and subsequent identification of single interaction partners by mass spectrometry. In silico analyses identified 11 putative Inc proteins of C. psittaci, of which 8 were further characterised. The transcriptional quantification of their gene expression enabled categorisation according to the phase of chlamydial development during the infection. Using split-Inc proteins, human interaction partners were identified for the Inc proteins CP0355, CP0856, CP0857, CP0558 and CP0598. These human interaction partners are associated with host cell expression, cytokinesis, cytoskeletal rearrangements, fatty acid metabolism and amino acid supply. The Inc proteins CP0534, CP0535 and CP0181 were suggested to participate in inclusion stability and organisation of Inc proteins in so-called microdomains in the inclusion. Investigation of doxycycline-induced persistence of C. trachomatis serovar D showed translational activity despite doxycycline treatment. It was assumed that trans-translation enables the active translation. The trans-translation, known from Escherichia coli, is a mechanism that dissociated a stalled translation complex. Transcriptional quantification showed that C. trachomatis serovar D transcribes components of the trans-translation mechanism, indicating that trans-translation supports the persistence. Subsequently, differences in the chlamydial proteome and inclusion-recruited host cell proteins were analysed during doxycycline treatment. The isolation of intact inclusions allowed to perform so-called label-free proteomics. The resulting proteins were identified by mass spectrometry and showed significant abundant IncD and Ras-related GTPase Rab12. Follow-up investigations demonstrated that the Inc protein IncD recruits the ceramide transport protein CERT during the persistence, underscoring a role in inclusion stability by enriched ceramides. The knockdown of Rab12 displayed an enhanced recovery of C. trachomatis serovar D after doxycycline treatment and a reduced progeny formation during the acute infection. Rab12 is involved in autophagy and iron homeostasis. This let suggest that Rab12-recruitment in acute infection supports chlamydial iron uptake and impedes autophagy of the inclusion during persistence. Using the results of the proteomes, Furthermore, differences in chlamydial protein regulation was analysed to determine changes in metabolic pathways using the proteome data. During persistence, enzymes of the tricarboxylic acid cycle were slightly increased as well as ABC transporter. Enzymes according to peptidoglycan synthesis and translation were reduced, while MreB, part of the divisome and cell division, was abundant in persistence. Based on the results and available publications, chlamydial persistence was elucidated. Therefore, chlamydial persistence is the consequence of stalled cell division. Any stimulus can induce persistence, if time of infection, treatment timing and stimulus concentration allow a basal chlamydial activity. In addition, the survival of C. trachomatis serovar D during the persistence depends on the stability of bacterial membrane and inclusion. In sum, new C. psittaci Inc proteins were identified and characterised. The determination of human host cell interaction partners provides new starting points to investigate C. psittaci. The newly established split-Inc protein method enables the mimicry of native interactions and serves a better opportunity to investigate interactions with Inc proteins, supporting future investigations. Finally, the doxycycline-induced persistence of C. trachomatis serovar D was elucidated and further factors were identified that help understanding the chlamydial development. The determination of translational activity during the doxycycline-induced persistence opens new starting points for interesting follow-up investigations.Die obligat intrazellulären Pathogene Chlamydia trachomatis und C. psittaci können Menschen infizieren, wohingegen C. psittaci auch Vögel infiziert. Während der intrazellulären Infektion replizieren und entwickeln sich die Bakterien in einer Einschlussmembran, die sogenannte Inklusion. Chlamydia sekretieren Proteine in die Inklusionsmembran, sogenannte Inklusionsmembranproteine, kurz Inc Proteine. Mit Hilfe dieser Proteine modifizieren Sie die Inklusionsmembran und interagieren mit Wirtszellproteinen. Je nach Spezies und Serovar können sie bestimmte Krankheiten verursachen und zu Folgeschäden führen, sollte die Behandlung fehlschlagen. Patienten, die mit C. trachomatis serovar D infiziert sind, werden mit dem Translationsinhibitor Doxycyclin behandelt. Doxycyclin induziert bei C. trachomatis serovar D einen Zustand, genannt Persistenz, der es ihnen ermöglicht, die Behandlung zu überstehen und anschließend die Infektion fortzufahren. Diese Arbeit identifiziert und charakterisiert C. psittaci Inc Proteine, und klärt den Mechanismus der Doxycyclin-induzierten Persistenz von C. trachomatis serovar D auf. C. psittaci, als zoonotischer Erreger von Vögeln und Menschen, wurde auf Wirtszellinteraktionen untersucht, um Spezies-übergreifende Ähnlichkeiten zu entschlüsseln und um die Grundlage der Fähigkeit, sich an verschiedene Wirte anzupassen, besser zu verstehen. Zur Untersuchung der Interaktionen zwischen Inc Proteinen und der Wirtszelle wurde eine neue Methode etabliert: Split-Inc Proteine. Die Split-Inc Proteine bauen auf das grün fluoreszierende Protein eGFP, welches die Membrandomäne der Inc Proteine ersetzt. Die Integration der N- und C-terminalen cytosolischen Domänen des Inc Proteins ermöglicht es, native Interaktionen zu imitieren. Mit Hilfe des eGFPs der Split-Inc Proteine können Proteininteraktionskomplexe co-immunopräzipitiert und einzelne Interaktionspartner in der Massenspektrometrie identifiziert werden. In silico-Untersuchungen identifizierten 11 mögliche Inc Proteine in C. psittaci, wovon 8 weiter charakterisiert wurden. Die transkriptionelle Quantifizierung ihrer Genexpression ermöglichte die Zuordnung zu bestimmten Phasen der chlamydialen Entwicklung während der Infektion. Unter Verwendung der Split-Inc Proteine wurden für die Inc Proteine CP0355, CP0856, CP0857, CP0558 und CP0598 humane Interaktionspartner identifiziert, die mit der Wirtszellexpression, Cytokinese, Organisation des Cytoskeletts der Wirtszelle, Fettsäuremetabolismus und Aminosäureversorgung zusammenhängen. Für die Inc Proteine CP0534, CP0535 und CP0181 wurde eine Beteiligung an der Stabilität der Inklusion und Organisation von Inc Proteinen in sogenannten Mikrodomänen in der Inklusion vorhergesagt. Die Untersuchung der Doxycyclin-induzierten Persistenz von C. trachomatis serovar D ergab, dass das Pathogen trotz Behandlung mit Doxycyclin translational aktiv ist. Es wurde vermutet, dass die aktive Translation durch die Trans-translation ermöglicht wird. Die Trans-translation, bekannt aus Escherichia coli, ist ein Mechanismus, der die Dissoziation eines ins Stocken geratenen Translationskomlpex bewirkt. Transkriptionelle Quantifizierung ergab, dass C. trachomatis serovar D Komponenten des Mechanismus transkribiert, weshalb angenommen wird, dass die Trans-translation zur Persistenz beiträgt. Anschließend wurden Änderungen des chlamydialen Proteoms und der Inklusionsrekrutierten Wirtszellproteine während der Doxycyclin-Behandlung untersucht. Sogenannte markierungsfreie Proteomics wurden durch die Isolierung intakter Inklusionen ermöglicht. Die resultierenden Proteine wurden per Massenspektrometrie identifiziert und ergaben signifikante Anreicherung vom Inc Protein IncD und der Ras-related GTPase Rab12. Folgeuntersuchungen ergaben, dass IncD das Ceramid-Transportprotein CERT während der Persistenz zur Inklusion rekrutiert, was eine Bedeutung der Inklusionsstabilität durch angereicherte Ceramide hervorhebt. Der Knock-down von Rab12 ergab eine verbesserte Erholung von C. trachomatis serovar D nach der Doxycyclin-Behandlung, reduzierte allerdings die Nachkommenbildung während der akuten Infektion. Rab12 ist an der Autophagie und der Eisenhomöostase beteiligt. Dies ließ vermuten, dass die Rab12-Rekrutierung in der akuten Infektion die chlamydiale Eisenaufnahme unterstützt und während der Persistenz die Autophagie der Inklusion verhindert. Weiterhin wurde mit Hilfe der Proteome die chlamydiale Proteinregulation analysiert, um Veränderungen bestimmter Stoffwechselwege zu ermitteln. Während der Persistenz sind Enzyme des Citratzyklus leicht erhöht, sowie einige ABC-Transporter. Enzyme der Peptidoglykansynthese und Translation waren reduziert, während MreB, Teil des Divisoms und der Zellteilung, in der Persistenz erhöht vorkam. Anhand der Ergebnisse und vorhandener Publikationen konnte die chlamydiale Persistenz aufgeklärt werden. Somit ist chlamydiale Persistenz die Folge von angehaltener Zellteilung. Jeder Stimulus kann zur Persistenz führen, wenn der Zeitpunkt der Infektion und Behandlungsbeginn, und die Konzentration des Stimulus eine basale chlamydiale Aktivität ermöglichen. Zudem ist das Überleben von C. trachomatis serovar D während der Persistenz von der Stabilität der bakteriellen Membran und Inklusion abhängig. Zusammenfassend konnten neue C. psittaci Inc Proteine identifiziert und charakterisiert werden. Die Ermittlung der humanen Wirtszellinteraktionspartner liefert neue und weitere Ansatzpunkte zur Untersuchung von C. psittaci. Die neu-etablierte Split-Inc Protein Methode ermöglicht die Imitation nativer Interaktionen und bietet somit eine verbesserte Möglichkeit zur Untersuchung von Interaktionen von Inc Proteinen, die bei zukünftigen Fragestellungen Anwendung finden kann. Zudem wurde die Doxycyclin-induzierte Persistenz von C. trachomatis serovar D aufgeklärt und weitere Faktoren identifiziert, die zur chlamydialen Entwicklung beitragen. Die Ermittlung aktiver Translation während der Doxycyclin-induzierten Persistenz bietet Ansätze für interessante Folgeuntersuchungen

Light control of orbital domains: case of the prototypical manganite La0.5Sr1.5MnO4

Control of electronic and structural ordering in correlated materials on the ultrafast timescale with light is a new and emerging approach to disentangle the complex interplay of the charge, spin, orbital and structural degree of freedom. In this paper we present an overview of how orbital order and orbital domains can be controlled by near IR and THz radiation in the layered manganite La0.5Sr1.5MnO4. We show how near-IR pumping can efficiently and rapidly melt orbital ordering. However, the nanoscale domain structure recovers unchanged demonstrating the importance of structural defects for the orbital domain formation. On the contrary, we show that pulsed THz fields can be used to effectively orientate the domains. In this case the alignment depends on the in-plane electric field polarisation and is induced by an energy penalty that arises from THz field induced hopping of the localised charges.Peer ReviewedPostprint (author's final draft

Superradiant Undulator Radiation for Selective THz Control Experiments at XFELs

The generation of frequency-tunable, narrow-bandwidth and carrier-envelope-phase stable THz pulses with fields in the MV/cm regime that can be appropriately timed to the femtosecond X-ray pulses from free-electron-lasers is of highest scientific interest. It will enable to follow the electronic and structural dynamics stimulated by (non)linear selective excitations of matter on few femtosecond time and {\AA}ngstrom length scales. In this article, a scheme based on superradiant undulator radiation generated just after the XFEL is proposed. The concept utilizes cutting edge superconducting undulator technology and provides THz pulses in a frequency range between 3 and 30 THz with exceptional THz pulse energies. Relevant aspects for realization and operation are discussed point by point on the example of the European XFEL

The role of processing-by-attribute noncompensatory choice models

AbstractResearch work on modeling consumer multiple choice problems using logit, regression, and probit is gaining more attention. However, in their work, Russ (1971), Tversky (1972), Newell and Simon (1972), Tversky and Sattath (1979), and Gensch and Svestka (1979; 1984) indicate that for many problems, choice behavior appears to be context dependent and hierarchical. With this specific issue in mind, this paper discusses a mathematical model which estimates threshold tolerances, eliminates nonchosen alternatives, provides choice probabilities and finally offers diagnostic information regarding the key attributes that are responsible for making a final decision. The use of other individual specific models such as: lexicographic, conjunctive, etc., have been briefly explicated

The agrin gene codes for a family of basal lamina proteins that differ in function and distribution

We isolated two cDNAs that encode isoforms of agrin, the basal lamina protein that mediates the motor neuron-induced aggregation of acetylcholine receptors on muscle fibers at the neuromuscular junction. Both proteins are the result of alternative splicing of the product of the agrin gene, but, unlike agrin, they are inactive in standard acetylcholine receptor aggregation assays. They lack one (agrin-related protein 1) or two (agrin-related protein 2) regions in agrin that are required for its activity. Expression studies provide evidence that both proteins are present in the nervous system and muscle and that, in muscle, myofibers and Schwann cells synthesize the agrin-related proteins while the axon terminals of motor neurons are the sole source of agrin

Influence of the impaction angle on the triboelectric charging of aerosol nanoparticles

A low pressure impactor is used to measure triboelectric charging behavior of metallic nanoparticles. Ag nanoparticles, produced by spark discharge, were impacted onto Pt sputtered targets. The influence of the impaction angle and impaction velocity on the triboelectric charging was investigated. While for perpendicular impaction the charge transfer behavior of previous work was confirmed, the oblique impaction revealed new phenomena. Additional charge transfer was observable, which increases with obliqueness. The possibility of mass transfer between particle and target due to the high-energy collisions was also investigated. SEM characterization and Auger spectroscopy indicate mass transfer from the particle to the target surface