Competitiveness of winter wheat stands against weeds: Effects of cultivar choice, row width and drilling direction

The need for competitive crop stands can be regarded as a basic requirement for weed control, potentially reducing the need for direct control measures. One way the crop may suppress weed growth is by the restriction of light through crop shading. As part of the EU-project ²Strategies of weed control in Organic Farming² (WECOF) trials with winter wheat were carried out to evaluate the potential of wheat shading ability as a weed control measure. Factors included were cultivar, row width and drilling direction. Results of the first experimental year are presented

Harmonic oscillator model for current- and field-driven magnetic vortices

In experiments the distinction between spin-torque and Oersted-field driven magnetization dynamics is still an open problem. Here, the gyroscopic motion of current- and field-driven magnetic vortices in small thin-film elements is investigated by analytical calculations and by numerical simulations. It is found that for small harmonic excitations the vortex core performs an elliptical rotation around its equilibrium position. The global phase of the rotation and the ratio between the semi-axes are determined by the frequency and the amplitude of the Oersted field and the spin torque

Muscarinic receptor-mediated intracellular Ca2+ mobilization in embryonic chick heart cells

AbstractActivation of muscarinic receptors of heart cells elevates the intracellular Ca2+ concentration. The increase is considered to be due to influx of extracellular Ca2+. We show that intracellular Ca2+ mobilization is involved. Cell suspensions prepared from hearts of 6-day-old chick embryos were loaded with the fluorescent Ca2+ chelator chlortetracycline. Muscarinic stimulation induces a dose-dependent fluorescence decrease (ED50=2.6 × 10−6 M) indicating intracellular Ca2+ mobilization

Konkurrenzkraft verschiedener Weizensorten unter dem Einfluss von Reihenabstand und Drillrichtung.

A competitive crop stand is a basis requirement for indirect weed control, potentially reducing the need for direct control measures. Efficient light interception by crop canopies can suppress weed growth by shading. As part of the EU-project ″Strategies of weed control in Organic Farming″ (WECOF) weed suppression by crop shading ability were evaluated in winter wheat. Three wheat cultivars with different leaf inclination and height (Greif, Astron, Pegassos) were grown at three row widths (12 cm, 17 cm and 24 cm) and two drilling directions (East-West, North-South) using a three-factorial design. Two field trials in 2000/01 and 2001/02, respectively, were conducted in Hennef, North-Rhine-Westphalia, Germany. No direct weed control measures were undertaken. Weed growth was influenced by both, cultivars´ morphology and row width, but remained unaffected by drilling direction. A tall and planophile cultivar (Pegassos) as well as narrow row width increased light interception of wheat stands, thus reducing weed ground cover and weed biomass. Leaf inclination and plant height became more important at wider row widths. The tallest planophile cultivar was able to suppress weeds at 24 cm row width as effectively as at 12 cm row width. Competitiveness of the shorter erectophile cultivar Greif decreased significantly with increasing row width. Furthermore cultivars´ ability for early covering enhanced competitiveness. The effectiveness of crop shading ability depends on weed species´ susceptibility to shading. Early-season growing and high statured weed species cannot be suppressed by crop shading effectively. Despite these limitations crop shading ability is regarded as an important element of weed control strategies in organic farming

Internet of Things-Specific Challenges for Enterprise Architectures: A Cross-Case Comparison of Explorative Projects from the smartPORT Initiative

By implementing new technologies, enterprise architectures and their respective models are subject to change. Current changes of the enterprise architecture are often driven by the IT megatrends. In this paper, we analyze six explorative projects from a logistics company that implemented Internet of Things (IoT) technology. Our analysis focusses on a cross-case comparison of the project specific enterprise architecture (EA) models based on an integrated model. The models and its meta-model were developed in an action design research based project. The results show that in-depth insights into IoT projects and a unified way of modelling support the process of analyzing the current architecture and deriving recommendations for the to-be architecture. Furthermore, we identify and discuss five IoT-specific EA challenges for future integration and roll-out projects and provide preliminary suggestions for overcoming them

Oxygen-minimum zone sediments in the northeastern Arabian Sea Sea off Pakistan: a habitat for the bacterium Thioploca

Filamentous sulfur-oxidizing bacteria and geochemical parameters of sediments at the Makran accretionary wedge in the northeastern Arabian Sea off Pakistan were studied. The upper continental slope between 350 and 850 m water depth, which is in the center of the oxygen-minimum zone, is characterized by numerous sites of small-scale seeps of methane- and sulfide-charged porewater. White bacterial mats with diameters <1 m were discovered at the surface of these sites using a photo-TV sled. Seep sediments, as well as non-seep sediments, in the vicinity were characterized by the occurrence of the bacterium Thioploca in near-surface layers between 0 and 13 cm depth. Thioploca bundles were up to 20 mm in length and contained up to 20 filaments of varying diameters, between 3 and 75 µm. Up to 169 ind. cm-2 were counted. Maximum numbers occurred in the top 9 cm of sediment, which contained very low concentrations of soluble sulfide (<0.2 µM) and high amounts of elemental sulfur (up to 10 µmol cm-3). Moderate sulfate reduction activity (between 20 and 190 nmol cm-3 d-1) was detected in the top 10 cm of these sediments, resulting in a gradual downcore decrease of sulfate concentrations. CO2 fixation rates had distinct maxima at the sediment surface and declined to background values below 5 cm depth. The nutritional implications of the distinct morphology of Thioploca and of the geochemical setting are discussed and compared to other sites containing Thioploca communities

Mass customization of teaching and learning in organizations

In search of methods that improve the efficiency of teaching and training in organizations, several authors point out that mass customization (MC) is a principle that covers individual needs of knowledge and skills and, at the same time, limits the development costs of customized training to those of mass training. MC is proven and established in the economic sector, and shows high potential for continuing education, too. The paper explores this potential and proposes a multidisciplinary, pragmatic approach to teaching and training in organizations. The first section of the paper formulates four design principles of MC deduced from an examination of economics literature. The second section presents amit™, a frame for mass customized training, designed according to the principles presented in the first section. The evaluation results encourage the further development and use of mass customized training in continuing education, and offer suggestions for future research

Masked suffix priming and morpheme positional constraints

Although masked stem priming (e.g., dealer\u2013DEAL) is one of the most established effects in visual word identification (e.g., Grainger et al., 1991), it is less clear whether primes and targets sharing a suffix (e.g., kindness\u2013WILDNESS) also yield facilitation (Giraudo & Grainger, 2003; Du\uf1abeitia et al., 2008). In a new take on this issue, we show that prime nonwords facilitate lexical decisions to target words ending with the same suffix (sheeter\uac\u2013TEACHER) compared to a condition where the critical suffix was substituted by another one (sheetal\u2013TEACHER) or by an unrelated non\u2013morphological ending (sheetub\u2013 TEACHER). We also show that this effect is genuinely morphological, as no priming emerged in non\u2013complex items with the same orthographic characteristics (sportel\u2013BROTHEL vs. sportic\u2013BROTHEL vs. sportur\u2013BROTHEL). In a further experiment, we took advantage of these results to assess whether suffixes are recognized in a position\u2013specific fashion. Masked suffix priming did not emerge when the relative order of stems and suffixes was reversed in the prime nonwords\u2014ersheet did not yield any time saving in the identification of teacher as compared to either alsheet or obsheet. We take these results to show that \u2013er was not identified as a morpheme in ersheet, thus indicating that suffix identification is position specific. This conclusion is in line with data on interference effects in nonword rejection (Crepaldi, Rastle, & Davis, 2010), and strongly constrains theoretical proposals on how complex words are identified. In particular, because these findings were reported in a masked priming paradigm, they suggest that positional constraints operate early, most likely at a pre\u2013lexical level of morpho\u2013orthographic analysi

Cholinergic receptor pathways involved in apoptosis, cell proliferation and neuronal differentiation

Acetylcholine (ACh) has been shown to modulate neuronal differentiation during early development. Both muscarinic and nicotinic acetylcholine receptors (AChRs) regulate a wide variety of physiological responses, including apoptosis, cellular proliferation and neuronal differentiation. However, the intracellular mechanisms underlying these effects of AChR signaling are not fully understood. It is known that activation of AChRs increase cellular proliferation and neurogenesis and that regulation of intracellular calcium through AChRs may underlie the many functions of ACh. Intriguingly, activation of diverse signaling molecules such as Ras-mitogen-activated protein kinase, phosphatidylinositol 3-kinase-Akt, protein kinase C and c-Src is modulated by AChRs. Here we discuss the roles of ACh in neuronal differentiation, cell proliferation and apoptosis. We also discuss the pathways involved in these processes, as well as the effects of novel endogenous AChRs agonists and strategies to enhance neuronal-differentiation of stem and neural progenitor cells. Further understanding of the intracellular mechanisms underlying AChR signaling may provide insights for novel therapeutic strategies, as abnormal AChR activity is present in many diseases