Combining probabilistic algorithms, Constraint Programming and Lagrangian Relaxation to solve the Vehicle Routing Problem

This paper presents an original hybrid approach to solve the Capacitated Vehicle Routing Problem (CVRP). The approach combines a Probabilistic Algorithm with Constraint Programming (CP) and Lagrangian Relaxation (LR). After introducing the CVRP and reviewing the existing literature on the topic, the paper proposes an approach based on a probabilistic Variable Neighbourhood Search (VNS) algorithm. Given a CVRP instance, this algorithm uses a randomized version of the classical Clarke and Wright Savings constructive heuristic to generate a starting solution. This starting solution is then improved through a local search process which combines: (a) LR to optimise each individual route, and (b) CP to quickly verify the feasibility of new proposed solutions. The efficiency of our approach is analysed after testing some well-known CVRP benchmarks. Benefits of our hybrid approach over already existing approaches are also discussed. In particular, the potential flexibility of our methodology is highlighted.     

A new bronchoscopic technique for the diagnosis of bacterial pneumonia in HIV-positive patients

The aim of the present study was to evaluate in HIV-positive patients with bacterial pneumonia, the diagnostic value of a new endoscopic technique that uses a single catheter to perform a telescopic plugged catheter (TPC) followed by a modified protected bronchoalveolar lavage (mpBAL). Fifty-eight HIV-positive patients with respiratory infection were included in the study. Samples from TPC and mpBAL were cultured quantitatively. Standard bronchoalveolar lavage was performed to rule out opportunistic infections. According to the clinical and microbiological results, patients were classified in the study group (27 with bacterial pneumonia) or the control group (31 without bacterial pneumonia). Sensitivity of TPC was 56% [95% confidence intervals (CI) 37-75%] and its specificity was 100%; these figures were 56% (CI, 37-75%) and 94% (CI, 86-100%) for mpBAL. When both techniques were assessed together, sensitivity increased to 70% (CI, 53-87%). The use of a single catheter reduced the cost of the originally described pBAL procedure by approximately 50%. The use of a single catheter to perform a TPC followed by a mpBAL can improve the diagnostic yield in HIV-positive patients with bacterial pneumonia, and reduces its cost.     

Digestibility, apparent mineral absorption, and voluntary intake by horses fed alfalfa, tall fescue, and caucasian bluestem

Alfalfa (Medicago sativa L.), low-endophyte (< 5%) tall fescue (Festuca arundinacea Schreb.), and caucasian bluestem (Bothriochloa caucasica [Trin.] C.E. Hubbard) were fed as chopped hay to six Arabian geldings (BW 441 kg; SE 2) in intake and digestibility experiments to determine nutritional value for horses at maintenance. Each experimental design was a replicated Latin square. Alfalfa was higher in DM and CP digestibility, IVDMD, apparent absorption of Ca, K, and S, and voluntary intake than the grasses (P < .05). Caucasian bluestem was higher in Zn but was lower in CP, TNC, Mg, P, K, S, and Cu concentrations than tall fescue. Crude protein digestibility and apparent absorption of Mg, K, and S were higher (P < .05) for tall fescue than for caucasian bluestem. Geldings fed alfalfa for ad libitum intake had higher serum concentrations of vitamin A, blood urea nitrogen, P, S, and Cu than geldings fed grass hays. Serum Zn was higher (P < .05), whole blood Se tended to be higher (P < .06), and BUN was lower (P < .05) in geldings fed caucasian bluestem than in those fed tall fescue. All forages met requirements for CP, Ca, Mg, K, and Fe when fed for ad libitum intake but were deficient in Cu for horses at maintenance. Caucasian bluestem was borderline in CP and was deficient in P but was the only forage that met the Zn requirement for the horses. Based on these results, caucasian bluestem could be a useful hay for horses but may require supplementation of CP and P.     

Left ventricular diastolic function in patients with type-I diabetes mellitus (based on pulsed Doppler echocardiographic data)

Diastolic function was studied of left ventricle by pulse Doppler echocardiography in 42 patients with type I diabetes mellitus (DM) and 46 essentially healthy individuals. In DM patients diastolic function was manifested by rise in peak velocity of atrial filling, decrease in ratio of peak velocity of early filling to that of late one, increase in left ventricular end-diastolic pressure. The findings available suggest the atrial phase has an important part in the structure of diastole in DM patients because of a combined influence of tachycardia and increased rigidity of left ventricular myocardium. Values for early filling in the patients did not differ from those in controls. A conclusion is drawn to the effect that in DM patients tachycardia and hypercatecholaminemia may partly mask disturbances in relaxation.