Iterative Processes Related to Riordan Arrays: The Reciprocation and the Inversion of Power Series

We point out how Banach Fixed Point Theorem, and the Picard successive approximation methods induced by it, allows us to treat some mathematical methods in Combinatorics. In particular we get, by this way, a proof and an iterative algorithm for the Lagrange Inversion Formula.Comment: 17 pages. We extend the results in the previuous version proving finally the Lagrange Inversion Formula via Banach Fixed Point Theore

Overdiagnosis and overtreatment of breast cancer: Overdiagnosis in randomised controlled trials of breast cancer screening

Data from randomised controlled trials of mammographic screening can be used to determine the extent of any overdiagnosis, as soon as either a time equivalent to the lead-time has elapsed after the final screen, or the control arm has been offered screening. This paper reviews those randomised trials for which breast cancer incidence data are available. In recent trials in which the control group has not been offered screening, an excess incidence of breast cancer remains after many years of follow-up. In those trials in which the control arm has been offered screening, although there is a possible shift from invasive to in situ disease, there is no evidence of overdiagnosis as a result of incident screens

Least-action perihelion precession

The precession of Mercury's perihelion is reinspected by the principle of least action. The anomalous advancement of the apside line that is customarily accounted by the theory of general relativity, is ascribed to the gravitational effect due to the entire Universe. When the least action is written in the Sun's frame of reference, the residual rotation is seen to stem from inertia due to all bodies in the Universe. Since mass corresponds to a bound form of energy, gravity, as any other force, can be described as an energy density difference between a system of bodies and its surrounding energy densities that are dispersed throughout the Universe. According to the principle of least action the Universe is expanding by combustion of mass to radiation in the quest of equilibrating the bound forms of energy with "zero-density surroundings" in least time. Keywords: cosmological principle; energy density; energy dispersal; evolution; gravity; the principle of least actionComment: 7 pages, 3 figure

Colon cancer risk and different HRT formulations: a case-control study

<p>Abstract</p> <p>Background</p> <p>Most studies have found no increased risk of colon cancer associated with hormone replacement therapy (HRT), or even a decreased risk. But information about the effects of different HRT preparations is lacking.</p> <p>Methods</p> <p>A case-control study was performed within Germany in collaboration with regional cancer registries and tumor centers. Up to 5 controls were matched to each case of colon cancer. Conditional logistic regression analysis was applied to estimate crude and adjusted odds ratios (OR) and 95% confidence intervals (95% CI). Stratified analyses were performed to get an impression of the risk associated with different estrogens and progestins.</p> <p>Results</p> <p>A total of 354 cases of colon cancer were compared with 1422 matched controls. The adjusted overall risk estimate for colon cancer (ColC) associated with ever-use of HRT was 0.97 (0.71 – 1.32). No clinically relevant trends for ColC risk were observed with increasing duration of HRT use, or increasing time since first or last HRT use in aggregate.</p> <p>Whereas the overall risk estimates were stable, the numbers in many of the sub-analyses of HRT preparation groups (estrogens and progestins) were too small for conclusions. Nevertheless, if the ColC risk estimates are taken at face value, most seemed to be reduced compared with never-use of HRT, but did not vary much across HRT formulation subgroups. In particular, no substantial difference in ColC risk was observed between HRT-containing conjugated equine estrogens (CEE) or medroxyprogesterone acetate (MPA) and other formulations more common in Europe.</p> <p>Conclusion</p> <p>Ever-use of HRT was not associated with an increased risk of colon cancer. In contrary, most risk estimates pointed non-significantly toward a lower ColC risk in HRT ever user. They did not vary markedly among different HRT formulations (estrogens, progestins). However, the small numbers and the overlapping nature of the subgroups suggest cautious interpretation.</p

Use of groundwater lifetime expectancy for the performance assessment of a deep geologic waste repository: 1. Theory, illustrations, and implications

Long-term solutions for the disposal of toxic wastes usually involve isolation of the wastes in a deep subsurface geologic environment. In the case of spent nuclear fuel, if radionuclide leakage occurs from the engineered barrier, the geological medium represents the ultimate barrier that is relied upon to ensure safety. Consequently, an evaluation of radionuclide travel times from a repository to the biosphere is critically important in a performance assessment analysis. In this study, we develop a travel time framework based on the concept of groundwater lifetime expectancy as a safety indicator. Lifetime expectancy characterizes the time that radionuclides will spend in the subsurface after their release from the repository and prior to discharging into the biosphere. The probability density function of lifetime expectancy is computed throughout the host rock by solving the backward-in-time solute transport adjoint equation subject to a properly posed set of boundary conditions. It can then be used to define optimal repository locations. The risk associated with selected sites can be evaluated by simulating an appropriate contaminant release history. The utility of the method is illustrated by means of analytical and numerical examples, which focus on the effect of fracture networks on the uncertainty of evaluated lifetime expectancy.Comment: 11 pages, 8 figures; Water Resources Research, Vol. 44, 200

The Clinical Research Office of the Endourological Society Percutaneous Nephrolithotomy Global Study: Nephrolithotomy in 189 Patients with Solitary Kidneys

Abstract Background and Purpose: The study compared characteristics and outcomes in patients with solitary and bilateral kidneys who were treated with percutaneous nephrolithotomy (PCNL) in the Clinical Research Office of the Endourological Society (CROES) PCNL Global Study. Patients and Methods: Data from consecutively treated patients from 96 centers worldwide were collated after a 1-year period. The following variables in patients undergoing PCNL with solitary or bilateral kidneys were compared: Prevalence, patient characteristics, intraoperative differences and outcomes, including bleeding and transfusion rates, renal function, and stone-free rates. Results: Data from 5803 patients were collated; 189 (3.3%) with solitary and 5556 (96.7%) with bilateral kidneys. Patient characteristics were well matched generally with the exception of cardiovascular disease and American Society of Anesthesiologists (ASA) risk scores, which were significantly greater in patients with solitary than with bilateral kidneys (P<0.0001 and P=0.004, respectively). Patients with solitary kidneys had also undergone significantly more procedures to remove calculi before this survey than bilateral patients (P= 00.049 ?<0.0001). Levels of renal impairment were significantly greater (P<0.0001) and stone-free rates were significantly lower (P=0.001) post-PCNL in solitary than bilateral kidney patients. Although bleeding rates were the same in both groups, transfusion rates were significantly greater in solitary kidney patients (P=0.014). Conclusions: Patients with a solitary kidney had a higher cardiovascular risk and ASA score. Outcomes related to morbidity and stone-free rate were less favorable for solitary kidneys.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98444/1/end%2E2011%2E0169.pd

Microvascular changes in renal allografts associated with FK506 (Tacrolimus) therapy

FK506 (Tacrolimus) recently has been shown to be an effective immunosuppressant after renal transplantation. It is associated with less hypertension, hypercholesterolemia and steroid use compared with cyclosporine. We report 10 patients on FK506 who showed fibrin thrombi within the glomerular capillaries and/or arterioles at renal allograft biopsy. These biopsies were generally performed to assess increasing serum creatinine levels; laboratory evidence of hemolytic uremic syndrome was present in one instance. Plasma or whole blood FK506 levels were elevated in eight of 10 cases. Reduction of immunosuppression led to clinical improvement or biopsy- proven resolution of thrombi in all cases. These observations suggest that FK506 may occasionally produce microvascular changes in the renal allograft. The estimated incidence of this occurrence (1%) is comparable with that reported with cyclosporine (3%)

Predictors of long-term function in older community-dwelling people who have presented to an emergency department after a fall: A cohort study

Aim: To identify factors predictive of function 12 months after a fall and emergency department (ED) presentation. Methods: This was a prospective cohort study with 608 older people who had a fall. After presentation and discharge from the ED, a baseline assessment was initially undertaken and then repeated after 12 months. The Human Activity Profile Adjusted Activity Score (HAP-AAS) at the 12-month follow-up assessment was the functional outcome measure. Results: Over the follow-up period, 37.3% (95% CI 33.4, 41.2) of participants declined in their HAP-AAS score. Increased age, pre-index fall functional impairment, poorer mobility/balance, and sustaining falls and severe injuries over the 12-month follow-up period were some of the factors predictive of a lower HAP-AAS score. Conclusion: This study highlights the importance of preventing falls in the 12 months after discharge from an ED. Some of the factors identified as being predictive of lower function are the same as those previously found to be predictive of falls