P\'olya number of continuous-time quantum walks

We propose a definition for the P\'olya number of continuous-time quantum walks to characterize their recurrence properties. The definition involves a series of measurements on the system, each carried out on a different member from an ensemble in order to minimize the disturbance caused by it. We examine various graphs, including the ring, the line, higher dimensional integer lattices and a number of other graphs and calculate their P\'olya number. For the timing of the measurements a Poisson process as well as regular timing are discussed. We find that the speed of decay for the probability at the origin is the key for recurrence.Comment: 8 pages, no figures. Accepted for publication in Physical Review

A Survey and Evaluation of Edge Detection Operators: Application to Text Recognition

Edge detection, especially in image processing occupies a special position. How to accurately extract the edge information of object in images has been the hot research. One of the main objectives of image analysis is to extract the dominating information. Segmentation of image is defined as being major step in image processing that extracts and describes the presence of significant object in a scene, often in the form of region or edges. This paper describes several edge detection operators like Sobel, Prewitt, Canny, Roberts, Zero threshold and emergence of combination of different spatial edge detection method, and its matlab simulation studies and comparative analysis

Short-course chemotherapy in neuro-tuberculosis - Brief review of clinical trials undertaken at the Tuberculosis Research Centre, Madras

Tuberculosis of the nervous system can present as tuberculous meningitis, tuberculoma of brain, Potts paraplegia, tuberculosis of spine and rarely as arachnoiditis and vasculitis. Tuberculosis is conventionally treated for 12 to 18 months to ensure adequate cure, stabilise quiescence and prevent relapses. With the introduction of rifampicin and pyrazinamide it became feasible to shorten the duration of chemotherapy to 6 to 9 months. Many controlled clinical trials conducted all over the world have confirmed the success of this approach in pulmonary tuberculosis by evolving 100% effective SCC regimens 1-5. In a few studies especially tuberculous lymphadenitis, tuberculous abdomen and pericarditis SCC has also been used and found to be as effective as conventional regimens6,7. However, only recently has SCC been tried for neurotuberculosis. This presentation briefly highlights some of the chemotherapy trials conducted at the Tuberculosis Research Centre in some areas of CNS tuberculosis8-10. What is SCC? SCC refers to chemotherapeutic regimens containing powerful bactericidal drugs like INH, Rifampicin and Pyrazinamide, by the use of which the duration of treatment of TB is reduced from the conventional 12 to 18 months to 6 to 9 months

Tuberculosis control strategies: Challenges to health management research

The rapid expansion of RNTCP implementation in this vast and diverse county with quality maintenance demands proactive involvement of policy makers, programme managers, researchers and health functionaries. Mid-term goal for the programme have to be defined. Problems in achieving these objectives have to be identified and a research agenda needs to be formulated to answer the constrains identified. Research, by being linked to the constrains and objectives, will always be relevant to TB control programme and the findings would influence policy and practice. Operational research should become an integral component of the programme management

Combining ability analysis and gene action of grain quality traits in rice (Oryza sativa L.) using line × tester analysis

In rice, twelve lines were crossed with five testers in a line × tester mating design and the resultant 60 hybrids along with their parents were evaluated for their combining ability effects for 15 grain quality traits. The results revealed that the ratio of GCA: SCA variances computed for all the fifteen grain quality traits showed the predominance of non-additive gene action. Among the lines, ADT (R) 47 showed significant desirable gca effects at 1% probability level (p = 0.01) for 11 grain quality traits viz., hulling percentage, milling percentage, head rice recovery percentage, kernel breadth, kernel breadth after cooking, breadth wise expansion ratio, gelatinization temperature, amylose content, gel consistency, water uptake and volume expansion ratio. Among the testers, Pusa 1460 showed significant desirable gca effects at 1% probability level (p = 0.01) for 10 grain quality traits viz., kernel length, kernel breadth, kernel length/breadth ratio, kernel length after cooking, kernel breadth after cooking, linear elongation ratio, gelatinization temperature, amylose content, water uptake and volume expansion ratio and hence they were adjudged as the best combiners for the improvement of the respective traits. Among the hybrids, the hybrids CO 47/Imp., Samba Mahsuri, ADT (R) 47/IRBB 21 and ADT (R) 46/IRBB 21 were identified as best hybrids for exploitation of grain quality traits since they revealed significant sca effects at 1% probability level (p = 0.01) for eight, eight and five grain quality traits, respectively

Rifampicin-induced renal toxicity during retreatment of patients with pulmonary tuberculosis

Rifampicin is a crucial component of treatment regimens for tuberculosis and has been in use since the early 1970’s. It is usually considered safe. Rarely life-threatening complications like acute renal failure or acute thrombocytopaenia may manifest during treatment with rifampicin. In our experience at the Tuberculosis Research Centre of treating more than 8000 pulmonary and extrapulmonary tuberculosis patients with rifampicin-containing regimens over the last 30 years, we are reporting 3 cases of probably rifampicininduced acute renal failure. Despite extreme therapeutic safety of this drug the clinician must be aware of this rare complication, which if detected early is completely reversible

A retrospective study of 'non-compliant' patients in controlled clinical trials of short course chemotherapy

In a total of 2,332 pulmonary short-course chemotherapy studies conducted during 1975-1985, there were 60 ‘noncompliant’ patients who had received less than 75% of the prescribed treatment. A retrospective study was undertaken to find out the reasons for default in these patients since the Tuberculosis Research Centre has very stringent criteria of selection of patients for their, studies, an adequate system. of motivation of the patients and well organised infrastructure for retrieval of the defaulters. Unwillingness for treatment was stated as the reason for default by 20 patients and adverse reactions to the drugs by 16 patients. Other major reasons given were pressure of work (14 patients), frequent outstation visits (13) and migration (12)

Chorionic gonadotropin and uterine dialogue in the primate

Implantation is a complex spatio-temporal interaction between the growing embryo and the mother, where both players need to be highly synchronized to be able to establish an effective communication to ensure a successful pregnancy. Using our in vivo baboon model we have shown that Chorionic Gonadotropin (CG), as the major trophoblast derived signal, not only rescues the corpus luteum but also modulates the uterine environment in preparation for implantation. This response is characterized by an alteration in both the morphological and biochemical activity in the three major cell types: luminal and glandular epithelium and stromal fibroblasts. Furthermore, CG and factors from the ovary have a synergistic effect on the receptive endometrium. Novel local effects of CG which influence the immune system to permit the survival of the fetal allograft and prevent endometrial cell death are also discussed in this review. An alternate extracellular signal-regulated kinase (ERK) activation pathway observed in epithelial endometrial cells and the possibility of differential expression of the CG/LH-R isoforms during gestation, open many questions regarding the mechanism of action of CG and its signal transduction pathway within the primate endometrium

New bounds on the classical and quantum communication complexity of some graph properties

We study the communication complexity of a number of graph properties where the edges of the graph $G$ are distributed between Alice and Bob (i.e., each receives some of the edges as input). Our main results are: * An Omega(n) lower bound on the quantum communication complexity of deciding whether an n-vertex graph G is connected, nearly matching the trivial classical upper bound of O(n log n) bits of communication. * A deterministic upper bound of O(n^{3/2}log n) bits for deciding if a bipartite graph contains a perfect matching, and a quantum lower bound of Omega(n) for this problem. * A Theta(n^2) bound for the randomized communication complexity of deciding if a graph has an Eulerian tour, and a Theta(n^{3/2}) bound for the quantum communication complexity of this problem. The first two quantum lower bounds are obtained by exhibiting a reduction from the n-bit Inner Product problem to these graph problems, which solves an open question of Babai, Frankl and Simon. The third quantum lower bound comes from recent results about the quantum communication complexity of composed functions. We also obtain essentially tight bounds for the quantum communication complexity of a few other problems, such as deciding if G is triangle-free, or if G is bipartite, as well as computing the determinant of a distributed matrix.Comment: 12 pages LaTe