The clustering coefficient of a scale-free random graph

We consider a random graph process in which, at each time step, a new vertex is added with m out-neighbours, chosen with probabilities proportional to their degree plus a strictly positive constant. We show that the expectation of the clustering coefficient of the graph process is asymptotically proportional to (log n)/n. Bollobas and Riordan have previously shown that when the constant is zero, the same expectation is asymptotically proportional to ((log n)^2)/n

Minimizing the oriented diameter of a planar graph

We consider the problem of minimizing the diameter of an orientation of a planar graph. A result of Chvátal and Thomassen shows that for general graphs, it is NP-complete to decide whether a graph can be oriented so that its diameter is at most two. In contrast to this, for each constant l, we describe an algorithm that decides if a planar graph G has an orientation with diameter at most l and runs in time O(c|V|), where c depends on l

Sexual function after suburethral sling removal for dyspareunia

Introduction: Impact on sexual function has received little attention in the medical literature for a long time. Because of the site of insertion of permanent tension free vaginal tape (TVT) the G spot might be affected or the tape might interfere with arousal and sensory stimulation. Recent studies have reported varying degrees of sexual impairment after TVT insertion ranging from 0% to 15% including dyspareunia. Aim: The aim of this study was to evaluate sexual function before and after suburethral sling removal due to postoperative female de novo dyspareunia. As a secondary outcome, general patients' satisfaction with their overall continence situation was assessed. Patients and methods: Between December 2005 and December 2007, we included 18 female patients who complained of de novo dyspareunia after suburethral sling insertion for urinary stress incontinence. All patients filled in an FSFI questionnaire prior to sling removal and at 3 months postoperatively. Additionally, all women were asked to estimate their general satisfaction regarding their continence situation using a Visual Analogue Scale (VAS) from 0 to 10, with 0 being the least satisfying situation and 10 being the most satisfying situation. All patients underwent gynaecological examination including ICS-pelvic organ prolapse staging (ICS-POP score). Results: Of the 18 slings, ten were transobturator tapes (6 × TVT-O, 2 × Monarch, 2 × unknown) and eight were retropubic tapes (7 × TVT, 1 × SPARC). Desire, arousal, lubrication, satisfaction, and pain improved statistically significant. Orgasm scores were low with median scoring of 1.5 scores before and 1.0 scores after sling removal, and they did not change significantly after sling removal. The satisfaction rate deteriorated from a median of 7 (95% confidence interval [CI] 6.3-7.7) to a median of 4 (95% CI 3.7-5.1; p=0.99) but not statistically significant. Conclusions: Sexual function in patients with de novo dyspareuina is likely to improve after sling removal but not in all domains. Bladder function may deteriorat

Some applications of graph theory

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.For the abstract of this thesis, please see the attached PDF.This work was funded by a Marie Curie Early Stage Training Fellowship (NET-ACE-programme) under grant number MEST-CT-2004-6724

Clustering and the hyperbolic geometry of complex networks

Clustering is a fundamental property of complex networks and it is the mathematical expression of a ubiquitous phenomenon that arises in various types of self-organized networks such as biological networks, computer networks or social networks. In this paper, we consider what is called the global clustering coefficient of random graphs on the hyperbolic plane. This model of random graphs was proposed recently by Krioukov et al. as a mathematical model of complex networks, under the fundamental assumption that hyperbolic geometry underlies the structure of these networks. We give a rigorous analysis of clustering and characterize the global clustering coefficient in terms of the parameters of the model. We show how the global clustering coefficient can be tuned by these parameters and we give an explicit formula for this function.Comment: 51 pages, 1 figur

Synergistische Effekte von Celecoxib und Zoledronsäre beim humanen Ovarialkarzinom in vitro

In der vorliegenden Arbeit wurde die synergistischen Effekte von Celecoxib und Zoledronsäure auf die humanen Ovarialkarzinomzelllinien BG1 und SKOV-3 mittels Proliferationassays, Flowcytometry und Western blot untersucht

Neoadjuvant bevacizumab and anthracycline-taxane-based chemotherapy in 678 triple-negative primary breast cancers; results from the geparquinto study (GBG 44)†

Background We evaluated the pathological complete response (pCR) rate after neoadjuvant epirubicin, (E) cyclophosphamide (C) and docetaxel containing chemotherapy with and without the addition of bevacizumab in patients with triple-negative breast cancer (TNBC). Patients and methods Patients with untreated cT1c-4d TNBC represented a stratified subset of the 1948 participants of the HER2-negative part of the GeparQuinto trial. Patients were randomized to receive four cycles EC (90/600 mg/m2; q3w) followed by four cycles docetaxel (100 mg/m2; q3w) each with or without bevacizumab (15 mg/kg; q3w) added to chemotherapy. Results TNBC patients were randomized to chemotherapy without (n = 340) or with bevacizumab (n = 323). pCR (ypT0 ypN0, primary end point) rates were 27.9% without and 39.3% with bevacizumab (P = 0.003). According to other pCR definitions, the addition of bevacizumab increased the pCR rate from 30.9% to 41.8% (ypT0 ypN0/+; P = 0.004), 36.2% to 46.4% (ypT0/is ypN0/+; P = 0.009) and 32.9% to 43.3% (ypT0/is ypN0; P = 0.007). Bevacizumab treatment [OR 1.73, 95% confidence interval (CI) 1.23-2.42; P = 0.002], lower tumor stage (OR 2.38, 95% CI 1.24-4.54; P = 0.009) and grade 3 tumors (OR 1.68, 95% CI 1.14-2.48; P = 0.009) were confirmed as independent predictors of higher pCR in multivariate logistic regression analysis. Conclusions The addition of bevacizumab to chemotherapy in TNBC significantly increases pCR rate

The economic impact of wolves on the moose harvest in Sweden

In Sweden hunters and wolves both have an interest in hunting moose. This thesis is therefore a contribution to the current carnivore-game conflict resulting from this interest. The use of a production function approach is applied in order to value the impact of wolves on hunting values. An open access model is developed which derives a regression equation setting hunters’ harvest of moose per km2 as the dependent variable. Data on wolves, the moose harvest, hunting licenses and different Swedish game series is included in the analysis. Estimating empirically for the study period from 2002 to 2011, we identify the marginal product of wolves, the marginal cost in terms of loss in hunting revenues. We also compare the level of hunting effort with and without wolves in the system. This is done in the short term and for a steady-state equilibrium in the long term. The latter assumes a constant moose population and thus an effort adjustment by hunters. Our findings suggest a significant negative impact of the wolf on the moose harvest. When looking at both national data and different county groupings, there appear to be differences in marginal impacts as well as costs. Wolves in the counties with high wolf densities have lower marginal impacts than in counties with fewer wolves. This is reasonable, as wolf packs kill similar amounts of moose per year irrespective of their size. The marginal productivity of hunting effort did not vary much within and between groupings, whether there were wolves present or not. Under the current debate, this study adds in terms of shedding light on the change in hunters’ harvest revenues by wolves. However, the results do not consider social costs and thus conclusions for the wolf policy in Sweden have to be made with caution. Actions already attempt to address the conflict, yet it remains to be seen whether they are effective

Application of the Micro Pixel Photon Counter to calorimetry and PET

Technological solutions are being investigated, in both fields of calorimetry and positron emission tomography, to increase the granularity of the detectors and achieve a better imaging resolution. The Geiger-mode avalanche photodiode looks a promising photo-detector for these compact designs. Up to now, the main limit of its application was the detection of the scintillation light, mostly ranging in the blue region: the traditional Geiger-mode avalanche photodiode is green sensitive. Hamamatsu has recently released a photo-detector of the same family, the Micro Pixel Photon Counter (MPPC), with a high photo-detection efficiency in the 420nm spectral region, opening a new scenario for the scintillator-based systems. The direct readout performances of a MPPC directly coupled to a plastic organic scintillator and to an inorganic scintillator (LSO) are systematically studied. Possible applications in highly granular calorimeters and positron emission tomography detectors are discussed