Elsevier - Publisher Connector
Not a member yet
1978752 research outputs found
Sort by
A negotiation-based algorithm to coordinate supplier development in decentralized supply chains
No full textAbstractIn this paper, we study supplier development in a decentralized supply chain with a single manufacturer and a single supplier. Because supplier development usually requires relationship-specific investments, the allocation of investment costs is a critical issue faced by participating firms. Referencing the relational view, we first investigate the effects of relationship-specific investments on the efficiency and effectiveness of supplier development. Next, we formulate and solve a continuous time optimal control model characterizing the decision to invest in supplier development and show that the supplier’s incentive to participate in supplier development critically depends on the manufacturer’s share of investment costs. The findings of our numerical analysis indicate that although the subsidy can lead to significant improvement in supply chain performance, subsidizing a constant share of investment costs is not always economically reasonable from the manufacturer’s point of view. Thus, we provide a negotiation-based algorithm that assists the manufacturing firm in gradually increasing the share of investment costs to ensure an efficient level of subsidy, resulting in both perfect supply chain coordination and a win–win situation
QALYs as a measure of value in cancer
No full textAbstractQuality adjusted life years (QALYs) offer a measure of value which is advantageous for health technology appraisal (HTA). As a composite measure, combining length of life and preference-based self-reported health related quality of life (HRQoL), the application of QALYs, and the assessment of value, in oncology and cancer care can be challenging. With respect to assessing the effectiveness of an intervention at reducing mortality, clinical trials in oncology predominantly focus on progression free survival, whereas overall survival is required for the estimation of QALYs. This is further complicated by crossover trial designs which have become common in oncology. Evaluating change in HRQoL often uses generic patient reported outcome measures. There is some evidence to suggest that these generic measures are not sensitive, and perhaps the estimated QALY gain does not accurately reflect the experience of a cancer patient. There have been suggestions that we broaden the definition of value to go beyond QALYs; further research is required to consider the feasibility of this, particularly in the context of informed decision making, when faced with constrained budgets
Efeitos de dexmedetomidina perineural no nervo ciático em ratos
No full textResumoO presente estudo foi desenvolvido para testar a hipótese de que dexmedetomidina em dose alta aumentaria a duração da antinocicepção a um estímulo térmico em modelo de rato de bloqueio do nervo ciático sem causar danos ao nervo. Os ratos foram anestesiados com isoflurano. Após os registros da eletromiografia (EMG), os nervos ciáticos direitos foram explorados e injeções perineurais foram administradas: Grupo D (n=7) recebeu 40μg/kg−1 de dexmedetomidina, Grupo II (n=6) recebeu 0,2mL de solução salina, Grupo III (n=2) recebeu apenas exploração cirúrgica do nervo ciático direito. O tempo de latência de retirada da pata (LRP) a um estímulo térmico para ambas as patas e uma avaliação da função motora foram avaliados a cada 30 minutos após o bloqueio do nervo até o retorno à fase basal. O potencial de ação muscular composto (PAMC) dos nervos ciático direito e esquerdo foi registrado 10 vezes para cada nervo, mais uma vez, após as injeções perineurais no 14° dia. Após os registros da EMG, o nervo ciático direito e parte do esquerdo foram excisados com um comprimento de no mínimo 15mm para exame histopatológico. A comparação das proporções da amplitude do PAMC direito/esquerdo antes e 14 dias após o procedimento mostrou uma diferença estatisticamente significativa (p=0,000). Não houve diferenças em inflamação perineural entre os grupos D, S e E aos 14 dias.AbstractThe present study was designed to test the hypothesis that high dose dexmedetomidine would increase the duration of antinociception to a thermal stimulus in a rat model of sciatic nerve blockade without causing nerve damage. The rats were anesthetized with isoflurane. After electromyography (EMG) recordings, right sciatic nerves were explored and perineural injections were delivered: Group D (n=7), 40μgμgkg−1 dexmedetomidine administration, Group II (n=6), (0.2mL) saline administration, Group III (n=2), only surgically exploration of the right sciatic nevre. Time to paw withdrawal latency (PAW) to a thermal stimulus for both paws and an assessment of motor function were measured every 30min after the nerve block until a return to baseline. The compound muscle action potential (CMAP) of right and left sciatic nerves were recorded 10 times per each nerve once more after perineural injections at 14 day. After EMG recordings, right and the part of left sciatic nerve were excised at a length of at minimum 15mm for histopathological examination. Comparison of right/left CMAP amplitude ratios before and 14 days after the procedure showed a statistically significant difference (p=0.000). There were no differences in perineural inflammation between the Group D, Group S, and Group E at 14 days
Liquid–solid mass transfer to a rotating mesh electrode in a rotor–stator spinning disc configuration
No full textAbstractHere we present the mass transfer coefficient for liquid–solid mass transfer to a rotating mesh electrode and a smooth flat disc electrode in a rotor–stator spinning disc reactor. The mass transfer coefficients are measured with the limiting current density technique. Additionally, the torque is measured and the energy dissipation rate in the system is calculated. The volumetric mass transfer coefficient of the mesh electrode increases a factor 5 compared to that of the flat disc electrode at virtually equal energy dissipation rates. Due to the characteristics of the mesh, the mesh electrode offers 2.77 times higher electrode area than the flat disc. The mass transfer coefficients measured for the rotating mesh electrode are a factor 1.74 higher compared to the flat disc. Average Sherwood numbers are reported and a correlation is presented that predicts mass transfer rates of rotating meshes in rotor–stator spinning disc reactor configurations
Pseudolymphoma of the liver: Report of a case and review of the literature
No full textSummaryWe report a case of pseudolymphoma of the liver in a 49-year-old woman without an underlying disease except for liver hemangioma. A 20-mm nodule was incidentally found in segment 2 of the liver by abdominal ultrasonography during a regular follow-up of the hepatic hemangioma. After a series of radiological examinations, a left lateral sectionectomy was performed because malignant hepatic tumor could not be excluded. The patient was discharged uneventfully 7 days after the operation. The pathology examination revealed a pseudolymphoma. No recurrence of the tumor was found 5½ years after the operation. To the best of our knowledge, only 46 cases of pseudolymphoma of the liver have been reported to date. A review of the literature showed that pseudolymphomas occur predominantly in females (89.4%), usually occur as a single tumor (80.4%), are no more than 20 mm in size (90.6%), and are frequently associated with either autoimmune disease or chronic liver disease. Because an accurate diagnosis is difficult to establish, vigilant follow-up is indicated, and surgical intervention is the choice of treatment once the suspiciousness of malignancy has been raised
Limits to tDCS effects in language: Failures to modulate word production in healthy participants with frontal or temporal tDCS
No full textAbstractTranscranial direct current stimulation (tDCS) is a method of non-invasive brain stimulation widely used to modulate cognitive functions. Recent studies, however, suggests that effects are unreliable, small and often non-significant at least when stimulation is applied in a single session to healthy individuals. We examined the effects of frontal and temporal lobe anodal tDCS on naming and reading tasks and considered possible interactions with linguistic activation and selection mechanisms as well as possible interactions with item difficulty and participant individual variability. Across four separate experiments (N, Exp 1A = 18; 1B = 20; 1C = 18; 2 = 17), we failed to find any difference between real and sham stimulation. Moreover, we found no evidence of significant effects limited to particular conditions (i.e., those requiring suppression of semantic interference), to a subset of participants or to longer RTs. Our findings sound a cautionary note on using tDCS as a means to modulate cognitive performance. Consistent effects of tDCS may be difficult to demonstrate in healthy participants in reading and naming tasks, and be limited to cases of pathological neurophysiology and/or to the use of learning paradigms
Donnan dialysis as membrane process for nitrate removal from drinking water: Membrane structure effect
No full textAbstractNitrates are extremely soluble in water and are considered as the renown pollutants of natural water and water table. Removing them through AMX, AM3, and RPA anion exchange membranes has been studied under donnan dialysis conditions as a function of concentration, pH and the nature of the feed phase. It was observed that the AMX membrane gives the highest nitrate transport efficiency and that the optimal concentration in the selected zone was in 6.2g/L (0.1M) with 37.9%. It was also observed that the best pH for the concentration of 0.62g/L is pH 10 with yield of 23%. Results are evaluated by the yield calculated with nitrates concentration detected by molecular absorption spectrometry in 212nm
Resistance to genetic insect control: Modelling the effects of space
No full textAbstractGenetic insect control, such as self-limiting RIDL22RIDL® is a registered trademark of Oxitec Limited, UK. (Release of Insects Carrying a Dominant Lethal) technology, is a development of the sterile insect technique which is proposed to suppress wild populations of a number of major agricultural and public health insect pests. This is achieved by mass rearing and releasing male insects that are homozygous for a repressible dominant lethal genetic construct, which causes death in progeny when inherited. The released genetically engineered (‘GE’) insects compete for mates with wild individuals, resulting in population suppression. A previous study modelled the evolution of a hypothetical resistance to the lethal construct using a frequency-dependent population genetic and population dynamic approach. This found that proliferation of resistance is possible but can be diluted by the introgression of susceptible alleles from the released homozygous-susceptible GE males. We develop this approach within a spatial context by modelling the spread of a lethal construct and resistance trait, and the effect on population control, in a two deme metapopulation, with GE release in one deme. Results show that spatial effects can drive an increased or decreased evolution of resistance in both the target and non-target demes, depending on the effectiveness and associated costs of the resistant trait, and on the rate of dispersal. A recurrent theme is the potential for the non-target deme to act as a source of resistant or susceptible alleles for the target deme through dispersal. This can in turn have a major impact on the effectiveness of insect population control
Pomeron pole plus grey disk model: Real parts, inelastic cross sections and LHC data
No full textAbstractI propose a two component analytic formula F(s,t)=F(1)(s,t)+F(2)(s,t) for (ab→ab)+(ab¯→ab¯) scattering at energies ≥100 GeV, where s,t denote squares of c.m. energy and momentum transfer. It saturates the Froissart–Martin bound and obeys Auberson–Kinoshita–Martin (AKM) [1,2] scaling. I choose ImF(1)(s,0)+ImF(2)(s,0) as given by Particle Data Group (PDG) fits [3,4] to total cross sections, corresponding to simple and triple poles in angular momentum plane. The PDG formula is extended to non-zero momentum transfers using partial waves of ImF(1) and ImF(2) motivated by Pomeron pole and ‘grey disk’ amplitudes and constrained by inelastic unitarity. ReF(s,t) is deduced from real analyticity: I prove that ReF(s,t)/ImF(s,0)→(π/lns)d/dτ(τImF(s,t)/ImF(s,0)) for s→∞ with τ=t(lns)2 fixed, and apply it to F(2). Using also the forward slope fit by Schegelsky–Ryskin [5], the model gives real parts, differential cross sections for (−t)<.3 GeV2, and inelastic cross sections in good agreement with data at 546 GeV, 1.8 TeV, 7 TeV and 8 TeV. It predicts for inelastic cross sections for pp or p¯p, σinel=72.7±1.0 mb at 7 TeV and 74.2±1.0 mb at 8 TeV in agreement with pp Totem [7–10] experimental values 73.1±1.3 mb and 74.7±1.7 mb respectively, and with Atlas [12–15] values 71.3±0.9 mb and 71.7±0.7 mb respectively. The predictions σinel=48.1±0.7 mb at 546 GeV and 58.5±0.8 mb at 1800 GeV also agree with p¯p experimental results of Abe et al. [47] 48.4±.98 mb at 546 GeV and 60.3±2.4 mb at 1800 GeV. The model yields for s>0.5 TeV, with PDG2013 [4] total cross sections, and Schegelsky–Ryskin slopes [5] as input, σinel(s)=22.6+.034lns+.158(lns)2 mb, and σinel/σtot→0.56, s→∞, where s is in GeV2 units. Continuation to positive t indicates an ‘effective’ t-channel singularity at ∼(1.5 GeV)2, and suggests that usual Froissart–Martin bounds are quantitatively weak as they only assume absence of singularities upto 4mπ2
Dendritic evolution during coarsening of Mg-Zn alloys via 4D synchrotron tomography
No full textAbstractThe scale of solidification microstructures directly impacts micro-segregation, grain size, and other factors which control strength. Using in situ high speed synchrotron X-ray tomography we have directly quantified the evolution of dendritic microstructure length scales during the coarsening of Mg-Zn hcp alloys in three spatial dimensions plus time (4D). The influence of two key parameters, solute composition and cooling rate, was investigated. Key responses, including specific surface area, dendrite mean and Gauss curvatures, were quantified as a function of time and compared to existing analytic models. The 3D observations suggest that the coarsening of these hcp dendrites is dominated by both the re-melting of small branches and the coalescence of the neighbouring branches. The results show that solute concentration has a great impact on the resulting microstructural morphologies, leading to both dendritic and seaweed-type grains. It was found that the specific solid/liquid surface and its evolution can be reasonably scaled to time with a relationship of ∼ t−1/3. This term is path independent for the Mg-25 wt%Zn; that is, the initial cooling rate during solidification does not greatly influence the coarsening rate. However, path independence was not observed for the Mg-38 wt%Zn samples because of the seaweed microstructure. This led to large differences in the specific surface area (Ss) and its evolution both between the two alloy compositions and within the Mg-38 wt%Zn for the different cooling rates. These findings allow for microstructure models to be informed and validated to improve predictions of solidification microstructural length scales and hence strength