Generalization of the convex-hull-and-line traveling salesman problem

Two instances of the traveling salesman problem, on the same node set (1,2 n} but with different cost matrices C and C, are equivalent iff there exist {a, hi: -1, n} such that for any 1 _i, j _n, j, C(i, j) C(i,j) q-a -t-bj [7]. One ofthe well-solved special cases of the traveling salesman problem (TSP) is the convex-hull-and-line TSP. We extend the solution scheme for this class of TSP given in [9] to a more general class which is closed with respect to the above equivalence relation. The cost matrix in our general class is a certain composition of Kalmanson matrices. This gives a new, non-trivial solvable case of TSP

Some Necessary Conditions and a General Sufficiency Condition for the Validity of A Gilmore-Gomory Type Patching Scheme for the Traveling

One of the most celebrated polynomially solvable cases of the TSP is the Gilmore-Gomory TSP. The patching scheme for the problem developed by Gilmore and Gomory has several interesting features. Its generalization, called the GG-scheme, has been studied by several researchers and polynomially testable sufficiency conditions for its validity have been given, leading to polynomial schemes for large subclasses of the TSP. A good characterization of the subclass of the TSP for which the GG-scheme produces an optimal solution, is an outstanding open problem of both theoretical and practical significance. We give some necessary conditions and a new, polynomially testable sufficiency condition for the validity of the GG-scheme that properly includes all previously known such conditions. Key words: Traveling salesman problem, Gilmore-Gomory TSP, Patching Scheme, Polynomially solvable case

The cost of treating stroke in urban and rural Tanzania: a 6-month pilot study

Background: Economic evaluations have significant roles in informing funding decisions. They provide the means to choose which programme of care to fund among the many competing for resources. Unlike in higher-income countries, published studies on economic evaluations of stroke in Sub-Saharan Africa are rare.Objective: To pilot a method for estimating the cost of treating stroke in rural and urban Tanzania that will assist with future economic evaluations of stroke.Methods: The pilot study was conducted as part of the Tanzania Stroke Incidence Study. Incident cases were reported by resident community informants. Cost data were summarised from project documents and data on out-ofpocket payments were collected by interviewing patients/carers. Productivity losses relating to post-stroke occupations were also estimated in monetary terms using standard monthly salary estimates by job category and gender.Results: Sixteen incident cases (11 rural and 5 urban) were identified and followed-up for six monthsin 2005/2006. The overall mean cost per case was TZS 256,338 (USD 220) and included diagnostic tests (blood, ECG, echocardiogram, chest X-ray, CT scans), hospitalisation cost (registration, inpatient stay and drugs), transport cost to designated hospitals, physiotherapy and out-of-pocket payments to other points of care. Costs were more than four-fold higher in the urban district than in the rural district. Mean productivity loss per patient was TZS 247,930 (USD 213) and was more than double in the urban district than in the rural district.Conclusion: This is the first published research investigating the cost of treating stroke in Tanzania. A bigger sample, long-term follow up and modeling are required for better estimates of stroke economic burden.Keywords: Cost analysis, Stroke, Tanzania, Sub-Saharan Africa, Populations Rural/Urba

2-Commodity Integer Network Synthesis Problem

We consider the following 2-commodity, integer network synthesis problem: Given two n×n, non-negative, symmetric, integer-valued matrices R = (rij) and S = (sij) of minimum flow requirements of 2 different commodities, construct an undirected network G = [N, E, c] on node set N = {1, 2, . . . , n} with integer edge capacities {c(e) : e ∈ E}, such that: (i) for any two pairs (i, j) and (k, l), i ≠ j, k ≠ l, of nodes in N, we can simultaneously send rij units of flow of commodity 1 from i to j and skl units of flow of commodity 2 from k to l in G; and (ii) z = Σ {c(e) : e ∈ E} is minimum. We present strongly polynomial, combinatorial algorithms for certain special cases of the problem; and for the general problem, we present a strongly polynomial, combinatorial algorithm that produces a feasible solution with objective function value no more than (the optimal objective function value +3)

Optimization of sliding specific wear and Frictional force behaviour of Modified ZA-27 alloy using Taguchi Method

Dry sliding wear behavior of Modified ZA-27 alloy was prepared by gravity die casting. The specific wear rate and frictional force of Modified ZA-27 alloy was studied by performing wear test using a pin-on-disc wear tester. Experiments were conducted according to plan of experiments generated using taguchi method. A L25 orthogonal array was used for analysis of data. ANOVA is used to study the influence of process parameters such as Normal load and sliding speed on specific wear rate and frictional force. Regression analyses are employed to find the optimal process parameter levels and to analyze the effect of these parameters on Modified ZA-27 alloy. The result reveals that Normal load and sliding speed were the more sensitive parameters. DOI: 10.17762/ijritcc2321-8169.15053

Analysis of Wear Behaviour of a Heat Treated Modified ZA-27 Alloy by Taguchi Technique

The aim of this paper is to examine the dry sliding wear beahviour of as-received and heat treated Modified ZA-27 alloy. The alloys were prepared by conventional melting and casting route technique. The as-received samples were annealed at 3700C for 5 hours, followed by water quenching and also furnace cooling. The experiments were conducted according to plan of experiments generated through taguchi technique. A L25 Orthogonal array was selected for analysis of the data along with the analysis of variance (ANOVA) were employed to investigate the influence of process parameters on the wear behaviour of as-received and heat treated Modified ZA-27 alloy. Regression models were used to investigate the influence of process parameter on wear rate. The result reveals that Normal Pressure is the more sensitive parameter

Symptomatic Hypocalcemia in Primary Hyperaldosteronism: A Case Report

The metabolic alterations caused by hyperaldosteronism are being increasingly recognized and have generated considerable interest among the medical fraternity. Hyperaldosteronism is suspected to have a pivotal role in the patho-physiology of congestive cardiac failure where it has been studied extensively. But its effects on calcium metabolism, parathyroid metabolism and renal handling of calcium are less well described. Recent experimental models have shed light into the roles played by previously unknown mechanisms in causing these metabolic alterations. We hereby report a case of primary hyperaldosteronism due to adrenal adenoma (Conn's syndrome) who presented with a myriad of clinical features including symptomatic hypocalcemia, significant weight loss along with uncontrolled hypertension for a prolonged period before eventually detected to have primary hyperaldosteronism. Surgical removal of the causative tumor resulted in prompt disappearance of all the symptoms and signs and regain of lost weight

Proteomics: in pursuit of effective traumatic brain injury therapeutics

Effective traumatic brain injury (TBI) therapeutics remain stubbornly elusive. Efforts in the field have been challenged by the heterogeneity of clinical TBI, with greater complexity among underlying molecular phenotypes than initially conceived. Future research must confront the multitude of factors comprising this heterogeneity, representing a big data challenge befitting the coming informatics age. Proteomics is poised to serve a central role in prescriptive therapeutic development, as it offers an efficient endpoint within which to assess post-TBI biochemistry. We examine rationale for multifactor TBI proteomic studies and the particular importance of temporal profiling in defining biochemical sequences and guiding therapeutic development. Lastly, we offer perspective on repurposing biofluid proteomics to develop theragnostic assays with which to prescribe, monitor and assess pharmaceutics for improved translation and outcome for TBI patients