Food safety as a field in supply chain management studies: a systematic literature review.

The increasing number of food contamination events has called the attention of both practitioners and scholars to food safety problems and their consequences. Many of these events are related to the supply chain because food production is now a global process of commoditized goods, made by large corporations that purchase inputs from producers in many countries. Given the linkage between supply chain and food safety issues, we investigated how studies in the supply chain management area have examined food safety issues, exploring some of their important characteristics. To do so, we conducted a systematic literature review of 46 papers, published in 23 journals, indexed in the Web of Science database. As a result, we pointed out some main characteristics of these papers, including journal attributes, authorship data, citation network, methodological characteristics, and theoretical approaches. Results serve as a reference to scholars and allow us to discuss some potential opportunities for future research in the field of food safety in the supply chain management area. Keywords: supply chain management, food safety, systematic literature review. JEL code: M11, L66, L23, Q56, M1

PEEP-ZEEP technique: cardiorespiratory repercussions in mechanically ventilated patients submitted to a coronary artery bypass graft surgery

<p>Abstract</p> <p>Background</p> <p>The PEEP-ZEEP technique is previously described as a lung inflation through a positive pressure enhancement at the end of expiration (PEEP), followed by rapid lung deflation with an abrupt reduction in the PEEP to 0 cmH₂O (ZEEP), associated to a manual bilateral thoracic compression.</p> <p>Aim</p> <p>To analyze PEEP-ZEEP technique's repercussions on the cardio-respiratory system in immediate postoperative artery graft bypass patients.</p> <p>Methods</p> <p>15 patients submitted to a coronary artery bypass graft surgery (CABG) were enrolled prospectively, before, 10 minutes and 30 minutes after the technique. Patients were curarized, intubated, and mechanically ventilated. To perform PEEP-ZEEP technique, saline solution was instilled into their orotracheal tube than the patient was reconnected to the ventilator. Afterwards, the PEEP was increased to 15 cmH₂O throughout 5 ventilatory cycles and than the PEEP was rapidly reduced to 0 cmH₂O along with manual bilateral thoracic compression. At the end of the procedure, tracheal suction was accomplished.</p> <p>Results</p> <p>The inspiratory peak and plateau pressures increased during the procedure (p < 0.001) compared with other pressures during the assessment periods; however, they were within lung safe limits. The expiratory flow before the procedure were 33 ± 7.87 L/min, increasing significantly during the procedure to 60 ± 6.54 L/min (p < 0.001), diminishing to 35 ± 8.17 L/min at 10 minutes and to 36 ± 8.48 L/min at 30 minutes. Hemodynamic and oxygenation variables were not altered.</p> <p>Conclusion</p> <p>The PEEP-ZEEP technique seems to be safe, without alterations on hemodynamic variables, produces elevated expiratory flow and seems to be an alternative technique for the removal of bronchial secretions in patients submitted to a CABG.</p

Influence of spin fluctuations on the superconducting transition temperature and resistivity in the t-J model at large N

Spin fluctuations enter the calculation of the superconducting transition temperature T$_c$ only in the next-to-leading order (i.e., in O(1/N$^2$) of the 1/N expansion of the t-J model. We have calculated these terms and show that they have only little influence on the value of T$_c$ obtained in the leading order O(1/N) in the optimal and overdoped region, i.e., for dopings larger than the instability towards a flux phase. This result disagrees with recent spin-fluctuation mediated pairing theories. The discrepancies can be traced back to the fact that in our case the coupling between electrons and spins is determined by the t-J model and not adjusted and that the spin susceptibility is rather broad and structureless and not strongly peaked at low energies as in spin-fluctuation models. Relating T$_c$ and transport we show that the effective interactions in the particle-particle and particle-hole channels are not simply related within the 1/N expansion by different Fermi surface averages of the same interactin as in the case of phonons or spin fluctuations. As a result, we find that large values for T$_c$ and rather small scattering rates in the normal state as found in the experiments can easily be reconciled with each other. We also show that correlation effects heavily suppress transport relaxation rates relative to quasiparticle relaxation rates in the case of phonons but not in the case of spin fluctuations.Comment: 16 pages, 10 figures, will appear in Phys. Rev.

Curr?culo tem?tico fundamentado em Freire - CTS: engajamento de professores de f?sica em forma??o inicial

This work resulted from reflection about physics teachers? experience in initial training, with the thematic approach based on Freire-STS (Paulo Freire?s Science ? Technology ? Society). We seek to answer the question: How teachers in initial training place themselves front of the possibility of performing curricular referrals guided by the thematic approach during his/ hers traineeship and/or in the course of their professional practice? We use the Discursive Textual Analysis to analyze questionnaires answered by those teachers at the end of the work. We identified three categories articulated to the curriculum as a result: (i) from the disciplinary fragmentation to the interdisciplinarity, (ii) issues of students? reality as a starting point, and (iii) thematic approach: curricular reconfiguration or new methodology? At the end, we signaled potentialities and challenges of thematic curriculum. Keywords: Thematic Curriculum, Freire-STS, Physics Teachers in Initial TrainingEste trabalho resultou da reflex?o sobre viv?ncia de professores(as) de f?sica, em forma??o inicial, com a abordagem tem?tica fundamentada em Freire-CTS. Buscamos responder ? pergunta: como professores(as) em forma??o inicial posicionamse frente ? possibilidade de realizar encaminhamentos curriculares pautados pela abordagem tem?tica durante seu est?gio curricular e/ou no decorrer da sua atua??o profissional? Utilizamos a An?lise Textual Discursiva para analisar question?rios respondidos por esses professores(as) ao final do trabalho. Como resultados, identificamos tr?s categorias articuladas ao curr?culo: (i) da fragmenta??o disciplinar ? interdisciplinaridade, (ii) temas da realidade dos estudantes como ponto de partida e (iii) abordagem tem?tica: reconfigura??o curricular ou nova metodologia? Ao final, sinalizamos desafios e potencialidades de curr?culos tem?ticos. Palavras-Chave: Curr?culo Tem?tico. Freire-CTS. Professores de f?sica em forma??o inicial

Modelo experimental de lesão pulmonar aguda para estudo de manobras de recrutamento alveolar

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τ\tauSPECT: A spin-flip loaded magnetic ultracold neutron trap for a determination of the neutron lifetime

The confinement of ultracold neutrons (UCNs) in a three dimensional magnetic field gradient trap allows for a measurement of the free neutron lifetime with superior control over spurious loss channels and can provide a large kinetic energy acceptance to enhance statistical sensitivity. In this paper, we present the first successful implementation of a pulsed spin-flip based loading scheme for a three-dimensional magnetic UCN trap. The measurements with the $\tau$SPECT experiment were performed at the pulsed UCN source of the research reactor TRIGA Mainz. We report on detailed investigations of major systematic effects influencing the neutron storage time, statistically limited by the size of the recorded data set. The extracted neutron storage time constant of $\tau = 859(16)\mathrm{s}$ is compatible with, but not to be interpreted as, a measurement of the free neutron lifetime.Comment: 15 pages, 19 figure