Buyer-supplier relationships influence on traceability implementation in the vegetable industry

The increasing importance of food safety has made traceability a crucial issue in the agri-business industry. In this article, we have analysed the factors that shape the buyer-supplier relationships, and how they influence the traceability of raw materials. In order to do so, first, we have made a literature review to develop an analytical framework. Next, we have carried out four case studies on vegetable firms with the purpose of uncovering the variables that characterise buyer-supplier relationships, and its influence on traceability in this sector. Finally, we have compared the observed links with the conceptual framework derived from the literature in order to build and improved model

Lagging behind versus advancing too fast? identifying gaps research in supply chain

The objective of our work is to analyze the evolution and actual trends of research in Supply Chain Management (SCM). We pretend to show how the different topics have been methodologically studied, and to determine how the advent of the so-called 'New Economy' has influenced SCM research. To get this objective, we carry out a literature review of twelve refereed journals in the Operations Management (OM) area for the period 1995-2001. Statistical tools are used to analyze the obtained information

Performance Measurement Systems, Competitive Priorities, and Advanced Manufacturing Technologies: Some Evidence from the Aeronautical Sector

Purpose – When acquiring advanced manufacturing technologies (AMT), the greatest caution should be taken regarding the performance measurement system to be used: the decision regarding new investments should not be conditioned by the excessive use of financial indicators to the detriment of the strategic objectives that motivated the investments. It is intended to analyze the aeronautical sector, for which the purchase of AMT is qualifying criteria, with two intentions: first, to identify the performance measurement systems that are used, and second, to test their correspondence with the objectives that motivated the investments. Design/methodology/approach – A survey of the 20 plants in the population was conducted via a postal questionnaire plus a structured interview. The unit of analysis has been maintained through the triangulation of data sources. Findings – The findings suggest that both financial and non-financial indicators are used, with the latter gaining predominance over the former on some occasions, even though there is no clear correspondence between strategy and the measurement of performance. In the light of the findings, the question of what inspires a company’s performance measurement system is still open, especially in those cases where there is no explicit strategy. With regard to practical implications, what seems to be indispensable is an improvement in the determination of the critical variables that should be used to measure performance. Research limitations/implications – Being valuable for academics and practitioners, this contribution relies, rather, on the possibility of a logical extrapolation to circumstances where the findings might apply, and researchers can judge whether the particular findings would be valid. Originality/value – Provides new evidence on the adaptation of the make-up and combination of the type of performance measures currently used by plants in the aeronautical industry, one of the sectors in which technological innovation is of the utmost importance.Publicad

Entry and Exit in a Liberalised Market

We analyse the entry and exit activity in the UK airline markets in the post-liberalisation period and study the differential traits between traditional and low cost carriers. Alongside with the characteristics traditionally highlighted as determinants of entry (e.g., airport presence and network economies), we find that the existence of charter or seasonal operators, product differentiation opportunities and the level of quality provided by the incumbents are also relevant in explaining entry and/or exit. Despite the liberalisation policies, the contestability of important large markets still seems to be limited.

Coupled electric and magnetic dipole formulation for planar arrays of dipolar particles: metasurfaces with various electric and/or magnetic meta-atoms per unit cell

The optical properties of infinite planar array of scattering particles, metasurfaces and metagratings, are attracting special attention lately for their rich phenomenology, including both plasmonic and high-refractive-index dielectric meta-atoms with a variety of electric and magnetic resonant responses. Herein we derive a coupled electric and magnetic dipole (CEMD) analytical formulation to describe the reflection and transmission of such periodic arrays, including specular and diffractive orders, valid in the spectral regimes where only dipolar multipoles are needed. Electric and/or magnetic dipoles with all three orientations arising in turn from a single or various meta-atoms per unit cell are considered. The 2D lattice Green function is rewritten in terms of a 1D (chain) version that fully converges and can be easily calculated. Modes emerging as poles of such lattice Green function can be extracted. This formulation can be applied to investigate a wealth of plasmonic, all-dielectric, and hybrid metasurfaces/metagratings of interest throughout the electromagnetic spectrum.Comment: 8 pages, 4 figure

Adopting and Implementing AMT: New Data on Key Factors from the Aeronautical Industry.

The objective of this paper is to take a greater in-depth look at which factors might be considered to be key to the performance of investments made in advanced manufacturing technologies (AMT), given their supposed positive effects, and on the influence that the time these factors are taken into account during the adoption and implementation process can have on that relationship. It provides a specially devised empirical analysis in the aeronautical sector in the south of Spain. A survey of the 20 plants in the population was conducted via a postal questionnaire between July 1999 and April 2001, with a structured interview being held at a later date. The testing of hypotheses was performed by applying the t-test to independent samples. The results show that the only factor that has a clear and positive effect on performance is the training of personnel. It can also be seen that a lack of strategic planning contributes to dampening the effects of investments. These results may be of some help to management staff and public administrators in charge of promoting the process of technological innovation, by indicating actions that need to be taken in order to successfully adopt and implement AMT.

Degenerate optical memory effect in dielectric films with randomly rough surfaces

9 págs.; 6 figs.By means of perturbation theory we calculate the angular intensity correlations of linearly polarized electromagnetic waves scattered from a thin dielectric film deposited on a planar perfectly conducting substrate. The illuminated surface is a one-dimensional, randomly rough surface with a power spectrum given either by a Gaussian, or by a rectangle defined to enhance the coupling into guided waves. The dielectric film supports, at least, two guided waves in the absence of the roughness that have distinct wave numbers at the frequency ω of the incident wave. We analyze the angular dependence of the optical memory effect: In addition to its two well known peaks, we demonstrate that, due to degeneracy of the excitation of guided waves, there appear two pairs of peaks symmetrically located about the former absolute maxima at positions related to the difference between the guided wave numbers. This degenerate memory effect is shown to be a multiple scattering effect. ©1997 American Physical SocietyThis work was supported by the Consejo Superior de Investigaciones Científicas and the Dirección General de Investigación Científica y Técnica through Grant No. PB93- 0973-C02-02.Peer Reviewe

Coupling, resonance transmission, and tunneling of surface-plasmon polaritons through metallic gratings of finite length

11 págs.; 10 figs.The Green's-theorem integral equation formulation is employed to study numerically the coupling into surface plasmon polaritons by illuminating a finite metal grating with a Gaussian beam from the vacuum half-space above the metal surface. A flat surface impedance boundary condition is used to simplify the scattering integral equations. The grating coupler period is chosen so that the first diffracted order excites a surface plasmon polariton and the zeroth diffracted order is the only radiating order. In particular, the surface magnetic field and the angular distribution of scattered intensity are calculated. These functions provide in turn the total intensity of the radiation scattered into the vacuum and the total power flow carried by the surface plasmon polariton, from which the energy balance is monitored. In this way, the zeroth order and coupling efficiencies are studied as functions of the angle of incidence θ0 and the grating coupler height sc, with the aim of analyzing the influence of the length of the illuminated coupler. Our results show that, when the illuminated coupler length is decreased, the photon-surface plasmon polariton coupling resonance broadens as a function of both θ0 and sc, and that larger values of sc. are required to optimize this coupling resonance. In addition, the coupling geometry is exploited to obtain the reflection and transmission coefficients, and the intensity of the scattered volume waves, of a surface plasmon polariton thus excited that impinges on another finite metal grating, called a grating scatterer. Two frequencies of the incoming surface plasmon polariton are considered that lie very close to the lower band edge of the gap in the surface plasmon polariton dispersion relation for the infinite grating scatterer. If the frequency is in the band, a strongly oscillating, resonant behavior of the transmission coefficient as a function of the grating length is obtained. For a frequency in the gap, transmission is negligible unless the grating is short enough that the surface plasmon polariton can tunnel through it. ©1996 American Physical SocietyFinancial support from the Spanish Consejo Superior de Investigaciones Científicas and the Dirección General de Investigación Científica y Técnica (Grant No. PB93- 0973-C02) is acknowledged. This work was supported in part by Army Research Office Grant No. DAAL 03-92-G- 0239.Peer Reviewe

Localized surface-plasmon polaritons in disordered nanostructured metal surfaces: Shape versus Anderson-localized resonances

4 págs.; 5 figs. ; PACS number~s!: 73.20.Mf, 42.25.2p, 68.37.Uv, 78.68.1mThe electromagnetic wave scattering from disordered nanostructured metal surfaces supporting surface-plasmon polaritons (SPP) is studied by means of fully retarded scattering formulations. We investigate the two physical mechanisms which may underlie the excitation of localized SPP: Anderson localization and shape resonances. The former mechanism is discarded since plane-wave excited, localized SPP are observed in the absence of proper Anderson localization of SPP. In contrast, a detailed analysis of the near field for various ensembles of surface realizations permits us to identify SPP shape resonances typically occurring at sub-100-nm grooves or ridges, the latter being significantly stronger. ©2003 American Physical SocietyThis work was supported in part by the Spanish DGIMCyT (Grants Nos. BFM2000-0806 and BFM2001-2265), and by NSF Grant No. INT-0084423.Peer Reviewe

High prevalence of double Plasmodium falciparum dhfr mutations at codons 108 and 59 in the Sistan-Baluchistan province, Iran

info:eu-repo/semantics/publishedVersio