Energy localization in the Phi(4) oscillator chain

We study energy localization in a finite one-dimensional Phi(4) oscillator chain with initial energy in a single oscillator of the chain. We numerically calculate the effective number of degrees of freedom sharing the energy on the lattice as a function of time. We find that for energies smaller than a critical value, energy equipartition among the oscillators is reached in a relatively short time. on the other hand, above the critical energy, a decreasing number of particles sharing the energy is observed. We give an estimate of the effective number of degrees of freedom as a function of the energy. Our results suggest that localization is due to the appearance, above threshold, of a breather-like structure. Analytic arguments are given, based on the averaging theory and the analysis of a discrete nonlinear Schrodinger equation approximating the dynamics, to support and explain the numerical results.

Chromophore relaxation in a side-chain methacrylate copolymer functionalized with 4-[N-ethyl-N-(2-hydroxyethyl)]amino-2 '-chloro-4 '-nitroazobenzene

A side-chain methacrylate copolymer functionalized with the nonlinear optical chromophore 4-[N-ethyl-N-(2-hydroxyethyl)]amino-2'-chloro-4'-nitroazobenzene, disperse red-13, was prepared and characterized. The chromophore relaxation was investigated measuring the decay of the electrooptic coefficient r(13) and the complex dielectric constant at different temperatures. Results obtained below and above T-g were analyzed using the Kohlrausch-Williams-Watts(KWW) equation, through the study of the temperature dependence of the KWW parameters. Above T-g the relaxation time experimental data were fitted to the Williams-Landel-Ferry (WLF) equation and its parameters determined. Chromophore relaxation leading to the decrease of electrooptic properties was found associated with a primary alpha relaxation. The obtained WLF equation parameters were introduced into the Adam-Gibbs-Tool-Narayanaswamy-Moynihan equation, and the overall relaxation time temperature dependence was successfully obtained in terms of the fictive temperature, accounting for the sample thermal treatment and allowing optimized thermal treatment to be found. The copolymer KWW stretching parameter at the glass transition temperature lies close to the limit value for short-range interactions, i.e., 0.6, suggesting that the chromophore group is participating in primary a relaxation.

Economic design of (X)over-bar charts with variable parameters: the Markov chain approach

This paper presents an economic design of (X) over bar control charts with variable sample sizes, variable sampling intervals, and variable control limits. The sample size n, the sampling interval h, and the control limit coefficient k vary between minimum and maximum values, tightening or relaxing the control. The control is relaxed when an (X) over bar value falls close to the target and is tightened when an (X) over bar value falls far from the target. A cost model is constructed that involves the cost of false alarms, the cost of finding and eliminating the assignable cause, the cost associated with production in an out-of-control state, and the cost of sampling and testing. The assumption of an exponential distribution to describe the length of time the process remains in control allows the application of the Markov chain approach for developing the cost function. A comprehensive study is performed to examine the economic advantages of varying the (X) over bar chart parameters.

Measuring supply chain management practices

Purpose: This paper aims to perform an empirical investigation about the constructs and indicators of the supply chain management practices framework. Design/methodology/approach: The measuring framework proposed is based on a survey that was carried out on 107 Brazilian companies. Statistical techniques were employed to verify, validate, and test the reliability of the constructs and their indicators. To validate this framework principal component analysis and structural equation modeling techniques were used. Findings: In general, previous studies suggest six constructs for measuring the supply chain management practices framework. However, in this study a framework was achieved with four constructs of supply chain management practices, namely, supply chain (SC) integration for production planning and control (PPC) support, information sharing about products and targeting strategies, strategic relationship with customer and supplier, and support customer order. This framework has adequate levels of validity and reliability. Research limitations/implications: The main limitation of this study was that only a small sample of companies in a single sector and country were surveyed, and therefore there needs to be further research considering the special conditions in other countries. Originality/value: This study investigated statistically set indicators to discuss the topic supply chain management practices. The framework obtained has good quality of validity and reliability indicators. Thus, an alternative framework has been added to measure supply chain management practices, which is currently a popular topic in the supply chain mainstream literature. Both defined constructs and the validated indicators can be used in other studies on supply chain management. © Emerald Group Publishing Limited.

Synthesis, crystal structure and magnetic properties of the helical oxalate-bridged copper(II) chain {[(CH3)(4)N](2)[Cu(C2O4)(2)] center dot H2O}(n)

The preparation, crystal structure and magnetic properties of a new oxalate-containing copper(II) chain of formula {[(CH3)(4)N](2)]Cu(C2O4)(2)] center dot H2O}(n) (1) [(CH3)(4)N+ = tetramethylammonium cation] are reported. The structure of 1 consists of anionic oxalate-bridged copper(II) chains, tetramethylammoniun cations and crystallization water molecules. Each copper(II) ion in 1 is surrounded by three oxalate ligands, one being bidentate and the other two exhibiting bis-bidenate coordination modes. Although all the tris-chelated copper(H) units from a given chain exhibit the same helicity, adjacent chains have opposite helicities and then an achiral structure results. Variable-temperature magnetic susceptibility measurements of 1 show the occurrence of a weak ferromagnetic interaction through the oxalate bridge [J = +1.14(1)cm(-1), the Hamiltonian being defined as H = -J Sigma nm S-i . S-j]. This value is analyzed and discussed in the light of available magnetostructural data for oxalate-bridged copper(H) complexes with the same out-of-plane exchange pathway. (C) 2012 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Effect of alkyl chain length of alcohols on nematic uniaxial-to-biaxial phase transitions in a potassium laurate/alcohol/K2SO4/water lyotropic mixture

Lyotropic liquid crystalline quaternary mixtures of potassium laurate (KL), potassium sulphate (K2SO4)/alcohol (n-OH)/water, with the alcohols having different numbers of carbon atoms in the alkyl chain (n), from 1-octanol to 1-hexadecanol, were investigated by optical techniques (optical microscopy and laser conoscopy). The biaxial nematic phase domain is present in a window of values of n = n(KL) +/- 2, where n(KL) = 11 is the number of carbon atoms in the alkyl chain of KL. The biaxial phase domain became smaller and the uniaxial-to-biaxial phase transition temperatures shifted to relatively higher temperatures upon going from 1-nonanol to 1-tridecanol. Moreover, compared with other lyotropic mixtures these new mixtures present high birefringence values, which we expect to be related to the micellar shape anisotropy. Our results are interpreted assuming that alcohol molecules tend to segregate in the micelles in a way that depends on the relative value of n with respect to nKL. The larger the value of n, the more alcohol molecules tend to be located in the curved parts of the micelle, favoring the uniaxial nematic calamitic phase with respect to the biaxial and uniaxial discotic nematic phases.

An assessment of the business value of traceability practices in the italian fishery processing industry

Traceability is often perceived by food industry executives as an additional cost of doing business, one to be avoided if possible. However, a traceability system can in fact comply the regulatory requirements, increase food safety and recall performance, improving marketing performances and, as well as, improving supply chain management. Thus, traceability affects business performances of firms in terms of costs and benefits determined by traceability practices. Costs and benefits affect factors such as, firms’ characteristics, level of traceability and ,lastly, costs and benefits perceived prior to traceability implementation. This thesis was undertaken to understand how these factors are linked to affect the outcome of costs and benefits. Analysis of the results of a plant level survey of the Italian ichthyic processing industry revealed that processors generally adopt various level of traceability while government support appears to increase the level of traceability and the expectations and actual costs and benefits. None of the firms’ characteristics, with the exception of government support, influences costs and level of traceability. Only size of firms and level of QMS certifications are linked with benefits while precision of traceability increases benefits without affecting costs. Finally, traceability practices appear due to the request from “external“ stakeholders such as government, authority and customers rather than “internal” factors (e.g. improving the firm management) while the traceability system does not provide any added value from the market in terms of price premium or market share increase.

Export Supply Chain Organization and Food Safety and Quality Standards: a case study of the Moroccan Fruit and Vegetable Sector

Agri-food supply chains extend beyond national boundaries, partially facilitated by a policy environment that encourages more liberal international trade. Rising concentration within the downstream sector has driven a shift towards “buyer-driven” global value chains (GVCs) extending internationally with global sourcing and the emergence of multinational key economic players that compete with increase emphasis on product quality attributes. Agri-food systems are thus increasingly governed by a range of inter-related public and private standards, both of which are becoming a priori mandatory, especially in supply chains for high-value and quality-differentiated agri-food products and tend to strongly affect upstream agricultural practices, firms’ internal organization and strategic behaviour and to shape the food chain organization. Notably, increasing attention has been given to the impact of SPS measures on agri-food trade and notably on developing countries’ export performance. Food and agricultural trade is the vital link in the mutual dependency of the global trade system and developing countries. Hence, developing countries derive a substantial portion of their income from food and agricultural trade. In Morocco, fruit and vegetable (especially fresh) are the primary agricultural export. Because of the labor intensity, this sector (especially citrus and tomato) is particularly important in terms of income and employment generation, especially for the female laborers hired in the farms and packing houses. Hence, the emergence of agricultural and agrifood product safety issues and the subsequent tightening of market requirements have challenged mutual gains due to the lack of technical and financial capacities of most developing countries.

All'origine dello squilibrio di potere negoziale della parte agricola nella food supply chain: il caso della suinicoltura in Emilia-Romagna

Il settore suinicolo ricopre un ruolo rilevante nel contesto nazionale, con ricadute economiche e sociali di primaria importanza in varie regioni. Tuttavia da alcuni anni il settore si trova in crisi a causa dell’instabilità dei mercati internazionali, dello scarso coordinamento tra gli attori della filiera, della progressiva riduzione della redditività dei prodotti trasformati a Denominazione di Origine, della mancata valorizzazione dei tagli di carne fresca, nonché della difficoltà di aggredire i mercati esteri. Altre criticità riguardano la distribuzione del valore lungo la filiera e la scarsa efficacia delle politiche di coordinamento finora adottate. L'obiettivo della ricerca è quello di identificare gli elementi che possono garantire maggiore equilibrio di potere negoziale tra allevatori suinicoli e macellatori rispetto alla situazione attuale: verificati gli elementi critici che caratterizzano la relazione commerciale tra allevatori e macellatori, si avanzano alcune proposte operative utili al superamento delle fratture tra la componente agricola e quella dei macelli in Emilia Romagna. La struttura della tesi è la seguente: (capitolo 1) si descrive il quadro economico del settore suinicolo a livello internazionale e nazionale. Successivamente (capitolo 2) si passano in rassegna le teorie economiche utili a comprendere le ragioni alla base del malfunzionamento dei rapporti tra gli attori della filiera agroalimentare, mentre nel terzo capitolo è richiamato il quadro normativo comunitario, nazionale e regionale all’interno del quale tali relazioni si configurano. Nel quarto capitolo si elabora un modello interpretativo al fine di spiegare le fratture che oggi contraddistinguono le relazioni in essere tra gli attori della filiera: il “modello delle fratture”. Alla luce di questa concettualizzazione è stata svolta un’indagine diretta svolta presso gli operatori aderenti all’Organizzazione Interprofessionale del Gran Suino Italiano, i cui risultati hanno consentito di valutare l’efficacia del modello interpretativo e di fornire indicazioni migliorative della strategia di governance delle relazioni tra allevatori e macellatori.

Predictive value of the MGMT promoter methylation status in metastatic melanoma patients receiving first-line temozolomide plus bevacizumab in the trial SAKK 50/07

The O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation status is a predictive parameter for the response of malignant gliomas to alkylating agents such as temozolomide. First clinical trials with temozolomide plus bevacizumab therapy in metastatic melanoma patients are ongoing, although the predictive value of the MGMT promoter methylation status in this setting remains unclear. We assessed MGMT promoter methylation in formalin-fixed, primary tumor tissue of metastatic melanoma patients treated with first-line temozolomide and bevacizumab from the trial SAKK 50/07 by methylation-specific polymerase chain reaction. In addition, the MGMT expression levels were also analyzed by MGMT immunohistochemistry. Eleven of 42 primary melanomas (26%) revealed a methylated MGMT promoter. Promoter methylation was significantly associated with response rates CR + PR versus SD + PD according to RECIST (response evaluation criteria in solid tumors) (p<0.05) with a trend to prolonged median progression-free survival (8.1 versus 3.4 months, p>0.05). Immunohistochemically different protein expression patterns with heterogeneous and homogeneous nuclear MGMT expression were identified. Negative MGMT expression levels were associated with overall disease stabilization CR+PR+SD versus PD (p=0.05). There was only a poor correlation between MGMT methylation and lack of MGMT expression. A significant proportion of melanomas have a methylated MGMT promoter. The MGMT promoter methylation status may be a promising predictive marker for temozolomide therapy in metastatic melanoma patients. Larger sample sizes may help to validate significant differences in survival type endpoints.

Fixed-Width Output Analysis for Markov Chain Monte Carlo

Markov chain Monte Carlo is a method of producing a correlated sample in order to estimate features of a complicated target distribution via simple ergodic averages. A fundamental question in MCMC applications is when should the sampling stop? That is, when are the ergodic averages good estimates of the desired quantities? We consider a method that stops the MCMC sampling the first time the width of a confidence interval based on the ergodic averages is less than a user-specified value. Hence calculating Monte Carlo standard errors is a critical step in assessing the output of the simulation. In particular, we consider the regenerative simulation and batch means methods of estimating the variance of the asymptotic normal distribution. We describe sufficient conditions for the strong consistency and asymptotic normality of both methods and investigate their finite sample properties in a variety of examples.

Origin and prognostic value of circulating KRAS mutations in lung cancer patients

Because of the current controversy on the origin and clinical value of circulating KRAS codon 12 mutations in lung cancer, we screened 180 patients using a combined restriction fragment-length polymorphism and polymerase chain reaction (RFLP-PCR) assay. We detected KRAS mutations in 9% plasma samples and 0% matched lymphocytes. Plasma KRAS mutations correlated significantly with poor prognosis. We validated the positive results in a second laboratory by DNA sequencing and found matching codon 12 sequences in blood and tumor in 78% evaluable cases. These results support the notion that circulating KRAS mutations originate from tumors and are prognostically relevant in lung cancer.

A single-centre cohort of patients with systemic light chain AL-amyloidosis treated with conventional chemotherapy or with high-dose chemotherapy and autologous stem cell transplantation.

BACKGROUND High-dose chemotherapy (HDCT) with autologous stem cell transplantation (ASCT) has been reported to confer better prognosis in systemic light chain AL-amyloidosis as compared with conventional chemotherapy. However, only limited data are available so far on treatment and outcome of AL-amyloidosis patients in Switzerland. METHODS Within a single-centre cohort of patients with biopsy confirmed AL-amyloidosis diagnosed between January 1995 and December 2012, we aimed to investigate treatment effects in patients treated with conventional chemotherapy versus HDCT with ASCT. RESULTS We identified 50 patients with AL-amyloidosis treated with conventional chemotherapy and 13 patients who received HDCT with ASCT. Clinical characteristics differed between the groups for the age of the patients (59 years for patients with ASCT/HDCT vs 69 years; p= 0.0006) and the troponin-T value (0.015 μg/l vs 0.08 μg/l; p = 0.0279). Patients with ASCT showed a trend towards better overall survival, with median survival not yet reached compared with 53 months in patients on conventional chemotherapy (p = 0.0651). CONCLUSION Our results suggest that light chain AL-amyloidosis patients considered fit to undergo HDCT and ASCT may have a better outcome than patients treated exclusively with conventional chemotherapy regimens; however, the better performance status of patients receiving HDCT may have added to this treatment effect.

Sources and proxy potential of long chain alkyl diols in lacustrine environments

Long chain 1,13- and 1,15-alkyl diols form the base of a number of recently proposed proxies used for climate reconstruction. However, the sources of these lipids and environmental controls on their distribution are still poorly constrained. We have analyzed the long chain alkyl diol (LCD) composition of cultures of ten eustigmatophyte species, with three species from different families grown at various temperatures, to identify the effect of species composition and growth temperature on the LCD distribution. The results were compared with the LCD distribution of sixty-two lake surface sediments, and with previously reported LCD distributions from marine environments. The different families within the Eustigmatophyceae show distinct LCD patterns, with the freshwater family Eustigmataceae most closely resembling LCD distributions in both marine and lake environments. Unlike the other two eustigmatophyte families analyzed (Monodopsidaceae and Goniochloridaceae), C28 and C30 1,13-alkyl diols and C30 and C32 1,15-alkyl diols are all relatively abundant in the family Eustigmataceae, while the mono-unsaturated C32 1,15-alkyl diol was below detection limit. In contrast to the marine environment, LCD distributions in lakes did not show a clear relationship with temperature. The Long chain Diol Index (LDI), a proxy previously proposed for sea surface temperature reconstruction, showed a relatively weak correlation (R2 = 0.33) with mean annual air temperature used as an approximation for annual mean surface temperature of the lakes. A much-improved correlation (R2 = 0.74, p-value<0.001) was observed applying a multiple linear regression analysis between LCD distributions and lake temperatures reconstructed using branched tetraether lipid distributions. The obtained regression model provides good estimates of temperatures for cultures of the family Eustigmataceae, suggesting that algae belonging to this family have an important role as a source for LCDs in lacustrine environments, or, alternatively, that the main sources of LCDs are similarly affected by temperature as the Eustigmataceae. The results suggest that LCDs may have the potential to be applicable as a palaeotemperature proxy for lacustrine environments, although further calibration work is still required.

The Effect of Product Classifications on the Formulation of Export Unit Value Indices: A Comparison of Export Unit Value Indices based on SITC and HS

With the globalization of economic activity, the relative weight of foreign trade in national economic activities has increased, and the question of how to measure trends in the value and quantity of international trade has become an important issue for policy-makers and economists. This paper compares the chain-linked indices formulated by Masato Kuroko, based on HS this fiscal year for individual industry categories and countries with chain-linked indices based on SITC-R1 codes, in order to study how changes in the quality composition of the same products, which cannot be considered using unit value indices based on SITC-R1 codes, can be considered using unit value indices based on the more detailed HS product classifications.