Cost effectiveness of photodynamic therapy with verteporfin for age related macular degeneration: the UK case

AIM: To estimate the potential cost effectiveness of photodynamic therapy (PDT) with verteporfin in the UK setting. METHODS: Using data from a variety of sources a Markov model was built to produce estimates of the cost effectiveness (incremental cost per quality adjusted life year (QALY) and incremental cost per vision year gained) of PDT for two cohorts of patients (one with starting visual acuity (VA) of 20/40 and one at 20/100) with predominantly classic choroidal neovascular disease over a 2 year and 5 year time horizon. A government perspective and a treatment cost only perspective were considered. Probabilistic and one way sensitivity analyses were undertaken. RESULTS: From the government perspective, over the 2 year period, the expected incremental cost effectiveness ratios range from £286 000 (starting VA 20/100) to £76 000 (starting VA 20/40) per QALY gained and from £14 000 (20/100) to £34 000 (20/40) per vision year gained. A 5 year perspective yields incremental ratios less than £5000 for vision years gained and from £9000 (20/40) to £30 000 (20/100) for QALYs gained. Without societal or NHS cost offsets included, the 2 year incremental cost per vision year gained ranges from £20 000 (20/100) to £40 000 (20/40), and the 2 year incremental cost per QALY gained ranges from £412 000 (20/100) to £90 000 (20/40). The 5 year time frame shows expected costs of £7000 (20/40) to £10 000 (20/100) per vision year gained and from £38 000 (20/40) to £69 000 (20/100) per QALY gained. CONCLUSION: This evaluation suggests that early treatment (that is, treating eyes at less severe stages of disease) with PDT leads to increased efficiency. When considering only the cost of therapy, treating people at lower levels of visual acuity would probably not be considered cost effective. However, a broad perspective that incorporates other NHS treatment costs and social care costs suggests that over a long period of time, PDT may yield reasonable value for money

James bundles

We study cubical sets without degeneracies, which we call {square}-sets. These sets arise naturally in a number of settings and they have a beautiful intrinsic geometry; in particular a {square}-set C has an infinite family of associated {square}-sets Ji(C), for i = 1, 2, ..., which we call James complexes. There are mock bundle projections pi: |Ji(C)| -> |C| (which we call James bundles) defining classes in unstable cohomotopy which generalise the classical James–Hopf invariants of {Omega}(S2). The algebra of these classes mimics the algebra of the cohomotopy of {Omega}(S2) and the reduction to cohomology defines a sequence of natural characteristic classes for a {square}-set. An associated map to BO leads to a generalised cohomology theory with geometric interpretation similar to that for Mahowald orientation

Unsolved Problems in Virtual Knot Theory and Combinatorial Knot Theory

This paper is a concise introduction to virtual knot theory, coupled with a list of research problems in this field.Comment: 65 pages, 24 figures. arXiv admin note: text overlap with arXiv:math/040542

Clinical negligence in the UK: Throwing the baby out with the bath water

As the total cost of clinical negligence claims has grown in the UK in recent years, calls for reform have resurfaced. The government now plans a White Paper on the subject next year. This paper assesses some of the economic arguments surrounding such reform. It suggests that the principle of negligence performs a useful economic function, that there is some uncertainty surrounding the precise costs of the UK's clinical negligence, and that costs of alternative systems may sometimes be larger than they first appear

Profit Maximization In The National Football League

This paper investigates if NFL teams maximize profits with respect to ticket price.  We modify Ferguson et al’s (1991) NHL paper as it pertains to the NFL.  A profit function incorporating variable revenue and cost factors such as gate receipts and player expenses is employed.  A systems model is used as the estimation procedure to identify the determinants of ticket prices for NFL franchises.  The model implies a Kuhn-Tucker based cross equation parameter restriction that result from attendance capacity constraints.  Results from the regression are then used in conjunction with other data to numerically test the first order necessary profit maximization conditions.  The results indicate that over 80% of NFL teams set ticket prices in a manner consistent with gate receipt and profit maximization

Doodles on surfaces

Doodles were introduced in but were restricted to embedded circles in the 2-sphere. Khovanov, extended the idea to immersed circles in the 2-sphere. In this paper we further extend the range of doodles to any closed oriented surfaces. Uniqueness of minimal representatives is proved, and various example of doodles are given with their minimal representatives. We also introduce the notion of virtual doodles, and show that there is a natural one-to-one correspondence between doodles on surfaces and virtual doodles on the plane

Community Structure in Time-Dependent, Multiscale, and Multiplex Networks

Network science is an interdisciplinary endeavor, with methods and applications drawn from across the natural, social, and information sciences. A prominent problem in network science is the algorithmic detection of tightly-connected groups of nodes known as communities. We developed a generalized framework of network quality functions that allowed us to study the community structure of arbitrary multislice networks, which are combinations of individual networks coupled through links that connect each node in one network slice to itself in other slices. This framework allows one to study community structure in a very general setting encompassing networks that evolve over time, have multiple types of links (multiplexity), and have multiple scales.Comment: 31 pages, 3 figures, 1 table. Includes main text and supporting material. This is the accepted version of the manuscript (the definitive version appeared in Science), with typographical corrections included her

X-Ray Microanalysis of Hollow Heart Potatoes

Electron microprobe and X-ray fluorescence techniques were used to study elemental gradients associated with the physiological disorder hollow heart i n potato tubers. Gradients were found along the length and across the width of mature tubers. These were not rela ted to the disorder, however . Tubers with advanced symptoms of the disorder had elemental levels and gradients similar to those in healthy, control tubers. The results suggest that if the disorder is initially caused by an elemental deficiency, as has sometimes been proposed , the deficiency is temporary and no longer exists in mature tubers with advanced hollow heart. Radial gradients were associated rnd inly with two contrasting tissues . the centra 1 pith and the surrounding perimedullary zone. Tissue differences are critical in microprobe studies involving small samples Microprobe studies of developing tubers containing incipient stages of hollow heart. employing strip samples restricted to the central pith where the disorder originates and taken so as to traverse the small lesions, showed a dramatic increase in Mg in lesion areas. It is suggested that a nutrient imbalance may trigger the onset of the cell necrosis that characterizes the initiation of hollow heart in potato . A localized Mg toxicity or Ca deficiency due to high Mg:Ca ratio is implicated