Centralised Versus Market-Based Control Under Environment Uncertainty: Case of the Mobile Task Allocation Problem (MTAP)

This paper aims at comparing the centralised versus the market-based approach. This is done in the context of the mobile task allocation problem (MTAP) from the perspective of environmental uncertainty. MTAP is defined as an optimization problem for planning the assignment of service tasks to mobile workers. Environmental uncertainty is introduced through the injection of stochastic tasks and dynamic travel delays. A multi-agent simulator is employed to experiment the behaviour of each approach in reaction to different uncertainty levels. Preliminary results suggest a tentative conceptual model to evaluate the suitability of each approach to address MTAP in function of uncertainty. It is suggested that uncertainty’s effect on achieved performance is moderated by the timeliness of decision making, workers’ degree of local knowledge, and problem’s complexity and size

Long-term follow-up of patients undergoing resection of tnm stage i colorectal cancer: an analysis of tumour and host determinants of outcome

Background Screening for colorectal cancer improves cancer-specific survival (CSS) through the detection of early-stage disease; however, its impact on overall survival (OS) is unclear. The present study examined tumour and host determinants of outcome in TNM Stage I disease. Methods All patients with pathologically confirmed TNM Stage I disease across 4 hospitals in the North of Glasgow between 2000 and 2008 were included. The preoperative modified Glasgow Prognostic Score (mGPS) was used as a marker of the host systemic inflammatory response (SIR). Results There were 191 patients identified, 105 (55 %) were males, 91 (48 %) were over the age of 75 years and 7 (4 %) patients underwent an emergency operation. In those with a preoperative CRP result (n = 150), 35 (24 %) patients had evidence of an elevated mGPS. Median follow-up of survivors was 116 months (minimum 72 months) during which 88 (46 %) patients died; 7 (8 %) had postoperative deaths, 15 (17 %) had cancer-related deaths and 66 (75 %) had non-cancer-related deaths. 5-year CSS was 95 % and OS was 76 %. On univariate analysis, advancing age (p < 0.001), emergency presentation (p = 0.008), and an elevated mGPS (p = 0.012) were associated with reduced OS. On multivariate analysis, only age (HR = 3.611, 95 % CI 2.049–6.365, p < 0.001) and the presence of an elevated mGPS (HR = 2.173, 95 % CI 1.204–3.921, p = 0.010) retained significance. Conclusions In patients undergoing resection for TNM Stage I colorectal cancer, an elevated mGPS was an objective independent marker of poorer OS. These patients may benefit from a targeted intervention

New Window on Optical Brain Imaging; Medical Development, Simulations and Applications

In this chapter we hope to give a technological review of near-infrared light and systems, discuss optode design considerations including background on the fiber design as it relates to this field and finally touch on current trends and applications. For the latter, we will focus on diffusion theory and simulation of photon propagation using a head model. We will follow this with concluding remarks

Factors associated with the efficacy of polyp detection during routine flexible sigmoidoscopy

Objective: Flexible sigmoidoscopy reduces the incidence of colonic cancer through the detection and removal of premalignant adenomas. However, the efficacy of the procedure is variable. The aim of the present study was to examine factors associated with the efficacy of detecting polyps during flexible sigmoidoscopy. Design and patients: Retrospective observational cohort study of all individuals undergoing routine flexible sigmoidoscopy in NHS Greater Glasgow and Clyde from January 2013 to January 2016. Results: A total of 7713 patients were included. Median age was 52 years and 50% were male. Polyps were detected in 1172 (13%) patients. On multivariate analysis, increasing age (OR 1.020 (1.016–1.023) p<0.001), male sex (OR 1.23 (1.10–1.38) p<0.001) and the use of any bowel preparation (OR 3.55 (1.47–8.57) p<0.001) were associated with increasing numbers of polyps being detected. There was no significant difference in the number of polyps found in patients who had received an oral laxative preparation compared with an enema (OR 3.81 (1.57–9.22) vs 3.45 (1.43–8.34)), or in those who received sedation versus those who had not (OR 1.00 vs 1.04 (0.91–1.17) p=0.591). Furthermore, the highest number of polyps was found when the sigmoidoscope was inserted to the descending colon (OR 1.30 (1.04–1.63)). Conclusions: Increasing age, male sex and the utilisation of any bowel preparation were associated with an increased polyp detection rate. However, the use of sedation or oral laxative preparation appears to confer no additional benefit. In addition, the results indicate that insertion to the descending colon optimises the efficacy of flexible sigmoidoscopy polyp detection

Speed optimization and bunkering in liner shipping in the presence of uncertain service times and time windows at ports

© 2016 The Authors. Recent studies in maritime shipping have concentrated on environmental and economic impacts of ships. In this regard, fuel is considered as one of the important factors for such impacts. In particular, the sailing speed of the vessels affects the fuel consumption directly. In this study, we consider a speed optimization problem in liner shipping, which is characterized by stochastic port times and time windows. The objective is to minimize the total fuel consumption while maintaining the schedule reliability. We develop a dynamic programming model by discretizing the port arrival times to provide approximate solutions. A deterministic model is presented to provide a lower bound on the optimal expected cost of the dynamic model. We also work on the effect of bunker prices on the liner service schedule. We propose a dynamic programming model for bunkering problem. Our numerical study using real data from a European liner shipping company indicates that the speed policy obtained by proposed dynamic model performs signi cantly better than the ones obtained by benchmark methods. Moreover, our results show that making speed decisions considering the uncertainty of port times will noticeably decrease fuel consumption cost.This research is supported in part by EU FP7 project MINI-CHIP (Minimising Carbon Footprint in Maritime Shipping) under grant number PIAP-GA-2013-611693

Physiological impacts of early defoliation on the cold hardiness of grapevine (Vitis vinifera L.) 'Sultana'

Low winter temperatures are one of the limiting factors of grape production worldwide. This study was undertaken to inquire about the effects of postharvest early defoliation on the cold hardiness of grapevine. The grapevines samples, cv. Sultana, were defoliated at two stages (10 and 25 days after harvest), and then they were compared with natural leaf fall. Cane samples were collected in December 2017 and February 2018, and analyzed in terms of water content, soluble carbohydrate, and proline concentrations in both bud and cane tissues. The samples were then subjected to freezing treatments i. e. -8, -12, -15, -18, -21, and -24 °C for evaluating the levels of cold hardiness. Based on these results, early defoliation reduced proline and soluble carbohydrate concentrations but increased the water content compared to the control. Leaf removal also decreased abscisic acid concentration in the bud samples. Investigation of cold hardiness by electrolyte leakage and tetrazolium staining examinations showed that the defoliation decreased cold hardiness. Results demonstrated that leaf removal between the growing season and the beginning of the acclimation stage decreased the metabolite concentration in buds and canes and resulted to a reduction of cold hardiness

Chaotic Inflation with Time-Variable Space Dimensions

Assuming the space dimension is not constant but decreases during the expansion of the Universe, we study chaotic inflation with the potential $m^2\phi^2/2$. Our investigations are based on a model Universe with variable space dimensions. We write down field equations in the slow-roll approximation, and define slow-roll parameters by assuming the number of space dimensions decreases continuously as the Universe expands. The dynamical character of the space dimension shifts the initial and final value of the inflaton field to larger values. We obtain an upper limit for the space dimension at the Planck length. This result is in agreement with previous works for the effective time variation of the Newtonian gravitational constant in a model Universe with variable space dimensions.Comment: 19 pages, To be published in Int.J.Mod.Phys.D. Minor changes to match accepted versio