Performance of the First ANTARES Detector Line

In this paper we report on the data recorded with the first Antares detector line. The line was deployed on the 14th of February 2006 and was connected to the readout two weeks later. Environmental data for one and a half years of running are shown. Measurements of atmospheric muons from data taken from selected runs during the first six months of operation are presented. Performance figures in terms of time residuals and angular resolution are given. Finally the angular distribution of atmospheric muons is presented and from this the depth profile of the muon intensity is derived.Comment: 14 pages, 9 figure

Time calibration of the ANTARES neutrino telescope

The ANTARES deep-sea neutrino telescope comprises a three-dimensional array of photomultipliers to detect the Cherenkov light induced by upgoing relativistic charged particles originating from neutrino interactions in the vicinity of the detector. The large scattering length of light in the deep sea facilitates an angular resolution of a few tenths of a degree for neutrino energies exceeding 10 TeV. In order to achieve this optimal performance, the time calibration procedures should ensure a relative time calibration between the photomultipliers at the level of similar to 1 ns. The methods developed to attain this level of precision are described

The positioning system of the ANTARES Neutrino Telescope

The ANTARES neutrino telescope, located 40km off the coast of Toulon in the Mediterranean Sea at a mooring depth of about 2475m, consists of twelve detection lines equipped typically with 25 storeys. Every storey carries three optical modules that detect Cherenkov light induced by charged secondary particles (typically muons) coming from neutrino interactions. As these lines are flexible structures fixed to the sea bed and held taut by a buoy, sea currents cause the lines to move and the storeys to rotate. The knowledge of the position of the optical modules with a precision better than 10cm is essential for a good reconstruction of particle tracks. In this paper the ANTARES positioning system is described. It consists of an acoustic positioning system, for distance triangulation, and a compass-tiltmeter system, for the measurement of the orientation and inclination of the storeys. Necessary corrections are discussed and the results of the detector alignment procedure are described

Performance of the front-end electronics of the ANTARES neutrino telescope

ANTARES is a high-energy neutrino telescope installed in the Mediterranean Sea at a depth of 2475 m. It consists of a three-dimensional array of optical modules, each containing a large photomultiplier tube. A total of 2700 front-end ASICs named Analogue Ring Samplers (ARS) process the phototube signals, measure their arrival time, amplitude and shape as well as perform monitoring and calibration tasks. The ARS chip processes the analogue signals from the optical modules and converts information into digital data. All the information is transmitted to shore through further multiplexing electronics and an optical link. This paper describes the performance of the ARS chip; results from the functionality and characterization tests in the laboratory are summarized and the long-term performance in the apparatus is illustrated.Comment: 20 pages, 22 figures, published in Nuclear Instruments and Methods

Limits on the production of scalar leptoquarks from Z (0) decays at LEP

A search has been made for pairs and for single production of scalar leptoquarks of the first and second generations using a data sample of 392000 Z0 decays from the DELPHI detector at LEP 1. No signal was found and limits on the leptoquark mass, production cross section and branching ratio were set. A mass limit at 95% confidence level of 45.5 GeV/c2 was obtained for leptoquark pair production. The search for the production of a single leptoquark probed the mass region above this limit and its results exclude first and second generation leptoquarks D0 with masses below 65 GeV/c2 and 73 GeV/c2 respectively, at 95% confidence level, assuming that the D0lq Yukawa coupling alpha(lambda) is equal to the electromagnetic one. An upper limit is also given on the coupling alpha(lambda) as a function of the leptoquark mass m(D0)

How standards compete: Comparative impact of coffee certification schemes in Northern Nicaragua

Item does not contain fulltextPurpose - Smallholder farmers are increasingly subject to different types of standards that offer specific conditions for their market incorporation. The proliferation of private and voluntary (civic) standards raises questions regarding their impact on farmers' welfare and their role in upgrading of value chains. Design/methodology/approach - Based on extensive fieldwork and careful matching of 315 farmers in Northern Nicaragua that produce coffee under Fair Trade, Rainforest Alliance and Café Practices labels or deliver to independent traders we compare the effects on income, production and investments. Moreover, the implications of different contract conditions for risk behaviour, organizational force, loyalty and gender attitudes are assessed Findings - We find that Fair Trade provides better prices compared to independent producers, but private labels outcompete Fair Trade in terms of yield and quality performance. While Fair Trade can be helpful to support initial market incorporation, private labels offer more suitable incentives for quality upgrading. Research limitations/implications - Civic standards exhibit major effects on local institutions and farmers behaviour, while B2B standards are more effective for improving production and management practices. Dynamic improvement standards may bridge the gap between both. Practical implications - Fair Trade standards are useful to provide initial market access to smallholders, but private standards offer better prospects for subsequent quality upgrading. Originality/value - This is the first large-scale comparative impact assessment of coffee standards that delivers un-biased empirical results.12 p

Determinants of market outlet choice for mango producers in Costa Rica

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Measuring the impact of fair trade on development

Item does not contain fulltextThis study of the impact of fair trade relies on new field data from coffee and banana co-operatives in Peru and Costa Rica, including a detailed assessment of its welfare effects by comparing FT farmers with non-FT farmers as a benchmark. Attention is focused on three major effects: (a) direct tangible impact of FT arrangements on the income, welfare, and livelihoods of rural households; (b) indirect effects of fair trade for improving credit access, capital stocks, investments, and attitudes to risk; and (c) institutional implications of fair trade for farmers' organisations and externalities for local and regional employment, bargaining, and trading conditions. Although direct effects in terms of net income remain fairly modest, important benefits are found to include capitalising farmers and strengthening their organisations

Managing quality heterogeneity in the mango supply chain: evidence from Costa Rica

Quality is a key aspect for evaluating the performance of commodity chains. Quality performance depends on both subjective consumer perceptions as well as intrinsic attributes of the product. Supply chain procedures and management activities influence the quality level and may reduce or increase the heterogeneity in product quality. In additional to technological measures, timely access to information on market and management options can be helpful to reduce human-related variability. In this article we present an explorative framework for disentangling the interactions between different managerial activities that have an effect on quality variability in mangoes. We use data dispersion statistics to understand the impact of technological and socio-economic factors on heterogeneity in quality performance at different stages of the supply chain. Based on a field survey amongst 51 different agents involved in the mango chain from Costa Rica, information regarding production technologies, agroecological conditions, management intensity, quality control, contracting practices and marketing operations is collected. We also tested randomly 10 mangoes from each agent to analyze the variability in quality attributes, focusing on the ratio between Brix and pH. We find that quality heterogeneity is influenced both by technological variability and by socio-economic diversity. In the mango supply chain from Costa Rica, management differences amongst agents vary depending on the upstream and downstream relationships. Agents related to international traders tend to maintain lowest variability in their management practices in order to be able to respond better to consumer demands. Effective linkages with downstream agents are thus critical to guarantee appropriate incentives for managing quality in upstream segments

Bargaining power and revenue distribution in the Costa Rican mango chain: a gaming simulation approach with local producers

Item does not contain fulltextBy the time a European consumer eats a Costa Rican mango, the product has been traded in several transactions between producers, traders, retailers and consumers. This paper investigates the position of Costa Rican smallholders in the mango supply chain in terms of bargaining power and revenue distribution. It examines data derived using a specially developed research tool: the Mango Chain Game (MCG), a gaming simulation that mimics the negotiation conditions in the Costa Rican mango supply chain. The MCG defines roles for all agents in the chain and records transaction attributes. Five sessions with the MCG were played with different groups of mango producers, resulting in a data set of 82 transactions and 43 bargaining power positions. Bargaining power was assessed at a 10-point Likert scale. Revenue distribution was measured in terms of value added. The results show that self-perceived bargaining power was dependent on negotiation skills, wealth and good partnership of the negotiators, but independent of market imperfections. Revenue distribution was related to the bargaining power of the trading partner, risk perception and the duration of the contract. Conclusions include that using a gaming simulation as data source can help identify less tangible issues in supply chain research, which is a new field of application for gaming simulations. Agency cooperation, skills and being able to bear risks play a role for improving the efficiency of the mango supply chain in Costa Rica as seen from a producers' perspective. The gaming results indicate that initiatives for improving the bargaining power of producers are more promising if they focus on improving skills and relations in trade rather than on solving market imperfections