5,139 research outputs found
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WSN based intelligent cold chain management
This paper presents a cold chain monitoring system which is implemented by using ubiquitous computing technologies, Radio Frequency Identification (RFID) & Wireless Sensor Network (WSN). In this paper, we discuss how cold supply chain works and how we can monitor and control cold supply chain by using wireless tracking and sensing technologies. We propose a prototype design which will provide a well controlled and transparent cold chain system, which could help the users to manage their productsâ environmental data in real time during the life cycle. Moreover, we highlight how the availability of product trace data in combination with historical condition-monitoring data can facilitate decision-making processes enhancing supply chainâs performance. Finally we discuss the integration works of these two technologies together in the cold supply chain management system. Hardware and software platform of WSN used in this system are also described in this paper
Evaluation of Decentralized Event-Triggered Control Strategies for Cyber-Physical Systems
Energy constraint long-range wireless sensor/ actuator based solutions are theoretically the perfect choice to support the next generation of city-scale cyber-physical systems. Traditional systems adopt periodic control which increases network congestion and actuations while burdens the energy consumption. Recent control theory studies overcome these problems by introducing aperiodic strategies, such as event trigger control. In spite of the potential savings, these strategies assume actuator continuous listening while ignoring the sensing energy costs. In this paper, we fill this gap, by enabling sensing and actuator listening duty-cycling and proposing two innovative MAC protocols for three decentralized event trigger contro l approaches. A laboratory experimental testbed, which emulates a smart water network, was modelled and extended to evaluate the impact of system parameters and the performance of each approach. Experimental results reveal the predominance of the decentralized event-triggered control against the classic periodic control either in terms of communication or actuation by promising significant system lifetime extension
Hybrid simulations of positively and negatively charged pickup ions and cyclotron wave generation at Europa
In the vicinity of Europa, Galileo observed bursty AlfvĂ©n-cyclotron wave power at thegyrofrequencies of a number of species including K+,O+2,Na+, and Cl+, indicating the localized pickupof these species. Additional evidence for the presence of chlorine was the occurrence of both left-hand(LH) and right-hand (RH) polarized transverse wave power near the Cl+gyrofrequency, thought to bedue to the pickup of both Cl+and the easily formed chlorine anion, Clâ. To test this hypothesis, we useone-dimensional hybrid (kinetic ion, massless fluid electron) simulations for both positive and negativepickup ions and self-consistently reproduce the growth of both LH and RH AlfvĂ©n-cyclotron waves inagreement with linear theory. We show how the simultaneous generation of LH and RH waves can result innongyrotropic ion distributions and increased wave amplitudes, and how even trace quantities of negativepickup ions are able to generate an observable RH signal. Through comparing simulated and observed waveamplitudes, we are able to place the first constraints on the densities of Chlorine pickup ions in localizedregions at Europa
Association of Over-The-Counter Pharmaceutical Sales with Influenza-Like-Illnesses to Patient Volume in an Urgent Care Setting
We studied the association between OTC pharmaceutical sales and volume of patients with influenza-like-illnesses (ILI) at an urgent care center over one year. OTC pharmaceutical sales explain 36% of the variance in the patient volume, and each standard deviation increase is associated with 4.7 more patient visits to the urgent care center (p<0.0001). Cross-correlation function analysis demonstrated that OTC pharmaceutical sales are significantly associated with patient volume during non-flu season (p<0.0001), but only the sales of cough and cold (p<0.0001) and thermometer (p<0.0001) categories were significant during flu season with a lag of two and one days, respectively. Our study is the first study to demonstrate and measure the relationship between OTC pharmaceutical sales and urgent care center patient volume, and presents strong evidence that OTC sales predict urgent care center patient volume year round. © 2013 Liu et al
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Strategic orientation, strategic renewal, and the international performance of born global firms
Copyright © Crown / The Author(s) 2023. The international business environment is both dynamic and turbulent. Accordingly, a new ventureâs strategic orientation (SO) and ability to undertake strategic renewal (SR) are of great importance to its survival, growth and international performance. Building on the dynamic capability perspective, we explore how SR capability mediates the relationship between SO and the performance of mature born global firms (BGFs). In particular, we examine the direct and indirect interplay between the SO of BGFs and their performance outcomes. We use a sample of 195 export-oriented BGFs, derived from the Bangladeshi apparel industry. We use a hierarchical regression analysis technique to test the direct effects. The mediation effect is examined using three statistical tests â Baron and Kenneyâs (1986) causal steps approach, the Sobel test, and the Hayes indirect effect with bootstrapping method â to ensure the validity and reliability of our findings. The results reveal a positive association between SO and the performance of BGFs, and that this relationship is mediated by the firmsâ SR capability. We contribute to a greater understanding of the drivers of mature BGFsâ international performance by demonstrating a direct link between their SO and SR capability, which in turn affects their performance outcomes
An inhibitory pull-push circuit in frontal cortex.
Push-pull is a canonical computation of excitatory cortical circuits. By contrast, we identify a pull-push inhibitory circuit in frontal cortex that originates in vasoactive intestinal polypeptide (VIP)-expressing interneurons. During arousal, VIP cells rapidly and directly inhibit pyramidal neurons; VIP cells also indirectly excite these pyramidal neurons via parallel disinhibition. Thus, arousal exerts a feedback pull-push influence on excitatory neurons-an inversion of the canonical push-pull of feedforward input
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Finite element analysis and calculation method of residual flexural capacity of post-fire RC beams
Fire tests and subsequent bending tests of fourreinforced concrete (RC) beamswere performed. Based on these tests, the post-fire performance of RCbeams was further studied using finite element simulation through reasonable selection of suitable thermal and thermodynamic parameters of steel and concrete materials. A thermodynamic model of RC beams with three sides under fire was built using finite element analysis(FEA)software ABAQUS. The FEA model was validated with the results of fire tests. Different factors were taken into account for further parametric studies in fire using the proposed FE model.The results show that the main factors affecting the fire resistance of the beamsare the thickness of the concretecover, reinforcement ratio of longitudinal steel,the fire exposure timeandthe fire exposure sides. Based on the strength reduction formula at high temperature of steel and concrete, animproved section method was proposed to develop a calculation formula to calculate the flexural capacity of RC beams after fire. The theoretical calculation method proposed in this paper shows good agreement with FEA results, which can be used to calculate the flexuralcapacity of RC beams after fire
HGF Mediates the Anti-inflammatory Effects of PRP on Injured Tendons
Platelet-rich plasma (PRP) containing hepatocyte growth factor (HGF) and other growth factors are widely used in orthopaedic/sports medicine to repair injured tendons. While PRP treatment is reported to decrease pain in patients with tendon injury, the mechanism of this effect is not clear. Tendon pain is often associated with tendon inflammation, and HGF is known to protect tissues from inflammatory damages. Therefore, we hypothesized that HGF in PRP causes the anti-inflammatory effects. To test this hypothesis, we performed in vitro experiments on rabbit tendon cells and in vivo experiments on a mouse Achilles tendon injury model. We found that addition of PRP or HGF decreased gene expression of COX-1, COX-2, and mPGES-1, induced by the treatment of tendon cells in vitro with IL-1ÎČ. Further, the treatment of tendon cell cultures with HGF antibodies reduced the suppressive effects of PRP or HGF on IL-1ÎČ-induced COX-1, COX-2, and mPGES-1 gene expressions. Treatment with PRP or HGF almost completely blocked the cellular production of PGE2 and the expression of COX proteins. Finally, injection of PRP or HGF into wounded mouse Achilles tendons in vivo decreased PGE2 production in the tendinous tissues. Injection of platelet-poor plasma (PPP) however, did not reduce PGE2 levels in the wounded tendons, but the injection of HGF antibody inhibited the effects of PRP and HGF. Further, injection of PRP or HGF also decreased COX-1 and COX-2 proteins. These results indicate that PRP exerts anti-inflammatory effects on injured tendons through HGF. This study provides basic scientific evidence to support the use of PRP to treat injured tendons because PRP can reduce inflammation and thereby reduce the associated pain caused by high levels of PGE2. © 2013 Zhang et al
Recent changes of water discharge and sediment load in the Yellow River basin, China
The Yellow River basin contributes approximately 6% of the sediment load from all river systems globally, and the annual runoff directly supports 12% of the Chinese population. As a result, describing and understanding recent variations of water discharge and sediment load under global change scenarios are of considerable importance. The present study considers the annual hydrologic series of the water discharge and sediment load of the Yellow River basin obtained from 15 gauging stations (10 mainstream, 5 tributaries). The Mann-Kendall test method was adopted to detect both gradual and abrupt change of hydrological series since the 1950s. With the exception of the area draining to the Upper Tangnaihai station, results indicate that both water discharge and sediment load have decreased significantly (p<0.05). The declining trend is greater with distance downstream, and drainage area has a significant positive effect on the rate of decline. It is suggested that the abrupt change of the water discharge from the late 1980s to the early 1990s arose from human extraction, and that the abrupt change in sediment load was linked to disturbance from reservoir construction.Geography, PhysicalGeosciences, MultidisciplinarySCI(E)43ARTICLE4541-5613
Microbial fuel cells: a green and alternative source for bioenergy production
Microbial fuel cell (MFC) represents one of the green technologies for the production of bioenergy. MFCs using microalgae produce bioenergy by converting solar energy into electrical energy as a function of metabolic and anabolic pathways of the cells. In the MFCs with bacteria, bioenergy is generated as a result of the organic substrate oxidation. MFCs have received high attention from researchers in the last years due to the simplicity of the process, the absence in toxic by-products, and low requirements for the algae growth. Many studies have been conducted on MFC and investigated the factors affecting the MFC performance. In the current chapter, the performance of MFC in producing bioenergy as well as the factors which inïŹuence the efïŹcacy of MFCs is discussed. It appears that the main factors affecting MFCâs performance include bacterial and algae species, pH, temperature, salinity, substrate, mechanism of electron transfer in an anodic chamber, electrodes materials, surface area, and electron acceptor in a cathodic chamber. These factors are becoming more inïŹuential and might lead to overproduction of bioenergy when they are optimized using response surface methodology (RSM)
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