Effect of rotation of cowpea (Vigna unguiculata) with fonio (Digitaria exilis) and millet (Pennisetum glaucum) on Macrophomina phaseolina densities and cowpea yield

Macrophomina phaseolina, the causal agent of charcoal rot, causes great damage to cowpea in the Sahel. One of the few options to manage the disease is by cropping nonhosts that may reduce the soil inoculum below a damage threshold level. To test this, fonio (Digitaria exilis) and millet (Pennisetum glaucum) were cropped continuously for 3 years in plots with a natural infestation of 24-53 microsclerotia g(-1) soil at the onset of the experiment. Next, a susceptible cowpea variety was grown to quantify disease incidence and severity on these soils. Fonio and millet both reduced microsclerotial densities in soils from the first year onwards. Reductions under fonio (81% after the 2(nd) year; 86% after the 3(rd) year) were significantly stronger than under millet (56 and 66% for the 2(nd) and 3(rd) year respectively). Fonio was not infected by M. phaseolina, while the root systems of millet had low densities of microsclerotia. Cowpea yielded significantly more hay and pods after 3 years of fonio than of millet. Cowpea yields and disease incidence (dead plants) could be explained well by pre-planting microsclerotial densities. We conclude that rotation of cowpea with a gramineous crop may lead to a relatively fast decline of inoculum density. In the case of a high inoculum density, fonio can be grown for three years to reduce M. phaseolina densities in soi

Informants in Organizational Marketing Research

Organizational research frequently involves seeking judgmental data from multiple informants within organizations. Researchers are often faced with determining how many informants to survey, who those informants should be and (if more than one) how best to aggregate responses when disagreement exists between those responses. Using both recall and forecasting data from a laboratory study involving the MARKSTRAT simulation, we show that when there are multiple respondents who disagree, responses aggregated using confidence-based or competence-based weights outperform those with data-based weights, which in turn provide significant gains in estimation accuracy over simply averaging respondent reports. We then illustrate how these results can be used to determine the best number of respondents for a market research task as well as to provide an effective screening mechanism when seeking a single, best informant.screening;marketing research;aggregation;organizational research;survey research

The Impact of Channel Function Performance on Buyer-Seller Relationships in Marketing Channels

Distributors, across sectors and countries, are faced by the threat of disintermediation. In many industries, horizontal consolidation and advances in information technology have made it easier for manufacturers to bypass distributors and do business directly with consumers. Distributors have responded to this threat or other destructive acts in a number of different ways that can be represented through Hirschman's (1970) Exit-Voice-Loyalty framework. One additional response that distributors frequently adopt is developing countervailing power through dependence-balancing actions. These actions are designed to strengthen bonds with customers and often manifest themselves in the provision of improved channel services to customers. Does this strategy work? We seek to address this in our paper. Specifically, we examine the nature and magnitude of the direct and interactive effects of (a) the performance of marketing functions and services by a distributor and (b) the dependence structure of its relationship with its customers on different dimensions of relationship quality - satisfaction, trust, commitment and conflict. Of particular interest to us is the effect of functional performance on relationship quality in situations characterized by high relative dependence of the distributor on the customer - this closely approximates the situation that many distributors, faced by the threat of disintermediation, find themselves in. Hypotheses from our model are tested using data collected from the paint industry in the Netherlands and Belgium.buyer-seller relationships;channel management;channel services;relationship marketing;empirical

Institutional Forecasting: The Performance of Thin Virtual Stock Markets

We study the performance of Virtual Stock Markets (VSMs) in an institutional forecasting environment. We compare VSMs to the Combined Judgmental Forecast (CJF) and the Key Informant (KI) approach. We find that VSMs can be effectively applied in an environment with a small number of knowledgeable informants, i.e., in thin markets. Our results show that none of the three approaches differ in forecasting accuracy in a low knowledge-heterogeneity environment. However, where there is high knowledge-heterogeneity, the VSM approach outperforms the CJF approach, which in turn outperforms the KI approach. Hence, our results provide useful insight into when each of the three approaches might be most effectively applied.Forecasting;Electronic Markets;Information Markets;Virtual Stock Markets

Particle Acceleration on Megaparsec Scales in a Merging Galaxy Cluster

Galaxy clusters form through a sequence of mergers of smaller galaxy clusters and groups. Models of diffusive shock acceleration (DSA) suggest that in shocks that occur during cluster mergers, particles are accelerated to relativistic energies, similar to supernova remnants. Together with magnetic fields these particles emit synchrotron radiation and may form so-called radio relics. Here we report the detection of a radio relic for which we find highly aligned magnetic fields, a strong spectral index gradient, and a narrow relic width, giving a measure of the magnetic field in an unexplored site of the universe. Our observations prove that DSA also operates on scales much larger than in supernova remnants and that shocks in galaxy clusters are capable of producing extremely energetic cosmic rays.Comment: Published in Science Express on 23 September 2010, 6 figures, Supporting Online Material included. This is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science, volume 330, 15 October 201

Diffuse radio emission in the merging cluster MACS J0717.5+3745: the discovery of the most powerful radio halo

Hierarchical models of structure formation predict that galaxy clusters grow via mergers of smaller clusters and galaxy groups, as well as through continuous accretion of gas. MACS J0717.5+3745 is an X-ray luminous and complex merging cluster, located at a redshift of 0.55. Here we present Giant Metrewave Radio Telescope (GMRT) radio observations at 610 MHz of this cluster. The main aim of the observations is to search for diffuse radio emission within the galaxy cluster MACS J0717.5+3745 related to the ongoing merger. These GMRT observations are complemented by Very Large Array (VLA) archival observations at 1.4, 4.9 and 8.5 GHz. We have discovered a radio halo in the cluster MACS J0717.5+3745 with a size of about 1.2 Mpc. The radio power P_1.4 GHz is 5 x 10^25 W/Hz, which makes it the most powerful radio halo known till date. A 700 kpc radio structure, which we classify as a radio relic, is located in between the merging substructures of the system. The location of this relic roughly coincides with regions of the intra-cluster medium (ICM) that have a significant enhancement in temperature as shown by Chandra. The major axis of the relic is also roughly perpendicular to the merger axis. This shows that the relic might be the result of a merger-related shock wave, where particles are accelerated via the diffuse shock acceleration (DSA) mechanism. Alternatively, the relic might trace an accretion shock of a large-scale galaxy filament to the south-west. The global spectral index of radio emission within the cluster is found to be -1.24 +/-0.05 between 4.9 GHz and 610 MHz. We derive a value of 5.8 microGauss for the equipartition magnetic field strength at the location of the radio halo. [abridged].Comment: 8 pages, 9 figures, accepted for publication in A&A on August 3, 200

Control of Alternaria alternata, Causal Agent of Dead (Dormant) Flower Bud Disease of Pear

Dead (dormant) flower buds of pear are an important phenomenon in pear production in the Netherlands. Vigourous or unbalanced tree growth and Pseudomonas syringae pv. syringae (P.s.s.) are mentioned as likely causes of dead flower buds. Pseudomonas syringae pv. syringae was occasionally isolated from diseased flower buds. However, Alternaria alternata was nearly always isolated from diseased buds and also often in symptomless flower buds. By identifying the causal agent of dead flower buds disease, an effective control strategy can be developed. In field trials it was proven that fungicide treatments can reduce disease incidences significantly

Child sexual abuse material networks on the darkweb: a multi-method approach

Because of the development of the internet and the associated digital opportunities, the crimes of possession and distribution of child sexual abuse material (CSAM) have gone through tremendous changes and developments over the last decennia. Nowadays, many CSAM offenders access and distribute CSAM through the Darkweb, the hidden and encrypted part of the internet. This book offers a description of the criminal process and the organization of CSAM fora on the Darkweb. Moreover, it describes how ‘keyplayers’ on such fora can be identified, and distinguishes various profiles and behavioral patterns of offenders active on Darkweb CSAM fora. Finally, the book describes how trust on the online fora is established. The studies described in this book provide an important, evidence-based contribution to the current knowledge on online CSAM offending. Extensively discussing practical implications for law enforcement and other professional organizations, this book is of relevance to academics as well as practitioners.Criminal Justice: Legitimacy, accountability, and effectivit