A dynamic simulation of a lean and agile manufacturing system

The integration of just-in-time and lean principles in agile manufacturing plays an important role in enhancing the operational performance of manufacturing systems. In this paper, we address this issue by (i) building a set of performance criteria for a typical manufacturing system, (ii) developing a system dynamics model for the system, and (iii) performing experimental “what-if” simulation analyses. Using a system dynamics simulation methodology, the impact of the application of lean and just-in-time policies on a traditional inventory-focused manufacturing system is investigated. System dynamics modelling is used to capture the dynamic causal linkages between different components of the manufacturing system. Different scenarios are generated in order to investigate the dynamics of the system under assumed demand scenarios. The results of the simulation study reveal that manufacturing systems can benefit from the introduction of lean and just-in-time principles, depending on the extent to which the necessary structural changes are implemented. The paper concludes by providing useful managerial insights for effective implementation of lean and agile manufacturing concepts

Non-coding RNAs and HIV: viral manipulation of host dark matter to shape the cellular environment

On October 28th 1943 Winston Churchill said “we shape our buildings, and afterward our buildings shape us” (Humes, 1994). Churchill was pondering how and when to rebuild the British House of Commons, which had been destroyed by enemy bombs on May 10th 1941. The old House had been small and insufficient to hold all its members, but was restored to its original form in 1950 in order to recapture the “convenience and dignity” that the building had shaped into its parliamentary members. The circular loop whereby buildings or dwellings are shaped and go on to shape those that reside in them is also true of pathogens and their hosts. As obligate parasites, pathogens need to alter their cellular host environments to ensure survival. Typically pathogens modify cellular transcription profiles and in doing so, the pathogen in turn is affected, thereby closing the loop. As key orchestrators of gene expression, non-coding RNAs provide a vast and extremely precise set of tools for pathogens to target in order to shape the cellular environment. This review will focus on host non-coding RNAs that are manipulated by the infamous intracellular pathogen, the human immunodeficiency virus (HIV). We will briefly describe both short and long host non-coding RNAs and discuss how HIV gains control of these factors to ensure widespread dissemination throughout the host as well as the establishment of lifelong, chronic infection

System dynamics simulation for strategic green supply chain management

The design of appropriate green supply chains in the manufacturing sector is a crucial task. The present paper seeks to (i) identify suitable performance measures for green supply chains and to (ii) develop a dynamic simulation model to assist supply chain decision-makers in developing appropriate policies and strategies in green supply chain management. Based on the principles of the system dynamics methodology, causal linkages between internal and external factors affecting the development of green strategies are investigated. Green concepts are used to develop crucial environmental and eco-efficiency performance measures in regards to strategic green supply management. Results from what-if analysis indicate that proper implementation of green strategies produces significant improvements for environmental, economic/financial and operational performance. Further numerical experiments demonstrate that the model can provide sound managerial insights

Super-Beacons: open-source probes with spontaneous tuneable blinking compatible with live-cell super-resolution microscopy

Localization based super-resolution microscopy relies on the detection of individual molecules cycling between fluorescent and non-fluorescent states. These transitions are commonly regulated by high-intensity illumination, imposing constrains to imaging hardware and producing sample photodamage. Here, we propose single-molecule self-quenching as a mechanism to generate spontaneous photoswitching independent of illumination. To demonstrate this principle, we developed a new class of DNA-based open-source Super-Resolution probes named Super-Beacons, with photoswitching kinetics that can be tuned structurally, thermally and chemically. The potential of these probes for live-cell friendly Super-Resolution Microscopy without high-illumination or toxic imaging buffers is revealed by imaging Interferon Inducible Transmembrane proteins (IFITMs) at sub-100nm resolutions

Association of activities related to pesticide exposure on headache severity and neurodevelopment of school-children in the rural agricultural farmlands of the Western Cape of South Africa

OBJECTIVE: Children and adolescents living in agricultural areas are likely to be exposed to mixtures of pesticides during their daily activities, which may impair their neurodevelopment. We investigated various such activities in relation to headache severity and neurodevelopment of school-children living in rural agricultural areas in the Western Cape of South Africa. METHOD: We used baseline date from 1001 school-children of the Child Health Agricultural Pesticide Cohort Study in South Africa (CapSA) aged 9-16 from seven schools and three agriculture areas in the Western Cape. Questionnaires were administrated to assess activities related to pesticide exposure and health symptoms addressing four types of activities: 1) child farm activities related to pesticide handling, 2) eating crops directly from the field, 3) contact with surface water around the field, and 4) seen and smelt pesticide spraying activities. Neurocognitive performance across three domains of attention, memory and processing speed were assessed by means of an iPad-based cognitive assessment tool, Cambridge Automated NeuroPsychological Battery (CANTAB). Headache severity was enquired using a standard Headache Impact Test (HIT-6) tool. Cross-sectional regression analysis was performed. RESULTS: About 50% of the cohort report to have ever been engaged in activities related to pesticide exposure including farm activities, eating crops directly from the field and leisure activities. Headache severity score was consistently increased in relation to pesticide-related farm activities (score increase of 1.99; 95% CI: 0.86, 3.12), eating crops (1.52; 0.41, 2.67) and leisure activities of playing, swimming or bathing in nearby water (1.25; 0.18, 2.33). For neurocognitive outcomes, an overall negative trend with pesticide exposure-related activities was observed. Among others, involvement in pesticide-related farm activities was associated with a lower multi-tasking accuracy score (-2.74; -5.19, -0.29), while lower strategy in spatial working memory (-0.29; -0.56; -0.03) and lower paired associated learning (-0.88; -1.60, -0.17) was observed for those who pick crops off the field compared to those who do not pick crops off the field. Eating fruits directly from the vineyard or orchard was associated with a lower motor screening speed (-0.06; -0.11, -0.01) and lower rapid visual processing accuracy score (-0.02; -0.03, 0.00). CONCLUSIONS: Children who indicate activities related to pesticide exposure may be at higher risk for developing headaches and lower cognitive performance in the domains of attention, memory and processing speed. However, self-reported data and cross-sectional design are a limitation. Future research in CapSA will consider pesticide exposure estimations via urinary biomarkers and longitudinal assessment of cognitive functions

Telemetric data logger and monitor for mining vehicles

Telemetry is the technology that allows data measurement at a distance. It uses data loggers which record data over time or in relation to location, either with built-in instruments or through instruments and sensors. The system discussed in the paper is based on a Peripheral Interface Controller (PIC18F4550), a series of sensors, a Radio Frequency (RF) link and a Graphical User Interface (GUI) developed using Visual Basic (VB). The system was designed to monitor mining vehicles by measuring engine temperature, transmission temperature, hydraulic oil temperature and hydraulic pressure in pumps and hoist cylinders. The data measured by the sensors in the mining vehicles (the plant) is transmitted to the Supervisory Control And Data Acquisition System (SCADA) through the RF link. The RF link uses a transmission frequency of 433.95 Mega Hertz (MHz) to enable flawless communication between the plant and the SCADA. The developed prototype was simulated using small pressurized containers and heating systems and the results were displayed on the GUI. The whole system development process was a multi-discipline project and it showed that RF communications are very reliable in data transmission