QuickHeapsort: Modifications and improved analysis

We present a new analysis for QuickHeapsort splitting it into the analysis of the partition-phases and the analysis of the heap-phases. This enables us to consider samples of non-constant size for the pivot selection and leads to better theoretical bounds for the algorithm. Furthermore we introduce some modifications of QuickHeapsort, both in-place and using n extra bits. We show that on every input the expected number of comparisons is n lg n - 0.03n + o(n) (in-place) respectively n lg n -0.997 n+ o (n). Both estimates improve the previously known best results. (It is conjectured in Wegener93 that the in-place algorithm Bottom-Up-Heapsort uses at most n lg n + 0.4 n on average and for Weak-Heapsort which uses n extra-bits the average number of comparisons is at most n lg n -0.42n in EdelkampS02.) Moreover, our non-in-place variant can even compete with index based Heapsort variants (e.g. Rank-Heapsort in WangW07) and Relaxed-Weak-Heapsort (n lg n -0.9 n+ o (n) comparisons in the worst case) for which no O(n)-bound on the number of extra bits is known

Effect of ion hydration on the first-order transition in the sequential wetting of hexane on brine

In recent experiments, a sequence of changes in the wetting state (`wetting transitions') has been observed upon increasing the temperature in systems consisting of pentane on pure water and of hexane on brine. This sequence of two transitions is brought about by an interplay of short-range and long-range interactions between substrate and adsorbate. In this work, we argue that the short-range interaction (contact energy) between hexane and pure water remains unchanged due to the formation of a depletion layer (a thin `layer' of pure water which is completely devoid of ions) at the surface of the electrolyte and that the presence of the salt manifests itself only in a modification of the long-range interaction between substrate and adsorbate. In a five-layer calculation considering brine, water, the first layer of adsorbed hexane molecules, liquid hexane, and vapor, we determine the new long-range interaction of brine with the adsorbate {\em across} the water `layer'. According to the recent theory of the excess surface tension of an electrolyte by Levin and Flores-Mena, this water `layer' is of constant, i.e.\ salt-concentration independent, thickness $\delta$, with $\delta$ being the hydrodynamic radius of the ions in water. Our results are in good agreement with the experimental ones.Comment: 27 pages, 2 tables, 4 figure

Perfusion of the interventricular septum during ventilation with positive end-expiratory pressure (PEEP)

Objective: To determine whether regional hypoperfusion of the interventricular septum occurs during ventilation with positive end-expiratory pressure. Design: Animal study. Animals: Anesthetized, closed chest dogs (n = 8). Interventions: Induction of experimental adult respiratory distress syndrome (ARDS) and then ventilation with 10,15, and 20 cm H2O of positive end-expiratory pressure. Measurements and Main Results: Cardiac output and regional interventricular septum blood flow 'were assessed at control, at induction of experimental ARDS, and at each level of positive end-expiratory pressure. Ventilation with 20 cm H2O of positive end-expiratory pressure decreased cardiac output (-32% vs. control, p <.05), and did not change absolute, but increased relative (to cardiac output) interventricular septum blood flow. During experimental ARDS and ventilation at 20 cm H2O end-expiratory pressure, there was a redistribution of flow toward the right ventricular free wall (+93%, p < .001) and the right ventricular part of the interventricular septum (+68%, p < .01), while flow to the left ventricular interventricular septum and to the left ventricular free wall remained unchanged. Locally hypoperfused interventricular septum areas or findings indicative of interventricular septum ischemia were not observed during positive end-expiratory pressure. Conclusions: The decrease in cardiac output during positive end-expiratory pressure is not caused by impaired interventricular septum blood supply. The preferential perfusion of the right ventricular interventricular septum indicates increased local right ventricular interventricular septum oxygen-demand and suggests that during positive end-expiratory pressure, this part of the interventricular septum functionally dissociates from the left ventricular interventricular septum and the left ventricular free wall to support the stressed right ventricle

CIS: A Web-Based Course Information System

This report surveys the design and implementation of CIS, a web-based Course Information System. CIS has been developed for the Computer Science I/II courses held between 2000 and 2003 by Prof. Dr. R. Loos, which were attended by 300 to 450 students. It maintains and presents each student's submissions and grades and holds related information such as worksheet texts, submission deadlines and the assignment of students to teaching assistents. In short, it covers most of the administrative data that comes up in regular university courses. CIS is designed to be used by first-year students conveniently. It aims at modelling real-world procedures, so that the system behaviour can be explained in well-known analogies. It is minimalistic, in the sense that it only takes on the routine work, while leaving the teacher free in any questions of structuring the contents of the course. Our problem statement and analysis focuses to two aspects: The requirements on the central data base and the interfaces for three groups of users: Students, teaching assistants, and teachers/adminis-trators. The actual implementation is straightforward, and we only mention particular decisions taken herein. CIS has been in use at the Wilhelm-Schickard Institut for three years, in courses organized both by the authors and others. The experiences indicate that the system can be considered reliable and mature. As the effort of setting up CIS is small, it has become feasible to employ it for several advanced courses with fewer than 20 students

Acute kidney injury after ingestion of rhubarb: secondary oxalate nephropathy in a patient with type 1 diabetes

Background: Oxalosis is a metabolic disorder characterized by deposition of oxalate crystals in various organs including the kidney. Whereas primary forms result from genetic defects in oxalate metabolism, secondary forms of oxalosis can result from excessive intestinal oxalate absorption or increased endogenous production, e.g. after intoxication with ethylene glycol. Case presentation: Here, we describe a case of acute crystal-induced renal failure associated with excessive ingestion of rhubarb in a type 1 diabetic with previously normal excretory renal function. Renal biopsy revealed mild mesangial sclerosis, but prominent tubular deposition of oxalate crystals in the kidney. Oxalate serum levels were increased. Conclusion: Acute secondary oxalate nephropathy due to excessive dietary intake of oxalate may lead to acute renal failure in patients with preexisting renal disease like mild diabetic nephropathy. Attention should be payed to special food behaviors when reasons for acute renal failure are explored

Anti-Inflammatory Characteristics of Local Anesthetics: Inhibition of TNF-α Secretion of Lipopolysaccharide-Stimulated Leucocytes in Human Blood Samples

Background. Local anesthetics (LAs) have potent anti-inflammatory properties. Inflammatory down-regulation is crucial in diseases with overactive immune reactions, such as acute respiratory distress syndrome (ARDS) and chronic inflammation. We investigated the influence of four LAs, procaine, lidocaine, mepivacaine, and bupivacaine, on the reduction of tumor necrosis factor-alpha (TNF-α) secretion in lipopolysaccharide (LPS)-activated human leucocytes. Methods. Blood samples of 28 individuals were stimulated with LPS. The reduction of TNF-α production by each of the four LAs added (0.5 mg/mL) was measured and correlated with biometric variables. A response was defined as reduction to <85% of initial levels. Results. All four LAs down-regulated the TNF-α secretion in 44–61%: Bupivacaine (44.4%), lidocaine (61.5%), mepivacaine (44.4%), and procaine (50% of the individuals, “responders”). The TNF-α secretion was reduced to 67.4, 68.0, 63.6, and 67.1% of the initial values in responders. The effects in both patients and healthy persons were the same. Interindividual responses to LAs were not correlated with the duration or type of complaints, basal TNF-α serum level, sex, BMI, or age of responders. Conclusions. Four clinically relevant LAs (amid-LA and ester-LA) attenuate the inflammatory response provoked by LPS. They are potential candidates for drug repositioning in treating overactive immune reactions and chronic inflammation

Relationship between running performance and weather in elite marathoners competing in the New York City Marathon

It is well known that weather and pacing have an influence on elite marathon performance. However, there is limited knowledge about the effect of weather on running speed in elite marathoners. The aim of the present cross-sectional study was to investigate potential associations between running speed and weather variables in elite runners competing in the ‘New York City Marathon’ between 1999 and 2019. Data from all official female and male finishers with name, sex, age, calendar year, split times at 5 km, 10 km, 15 km, 20 km, 25 km, 30 km, 35 km, 40 km and finish and hourly values for temperature (°Celsius), barometric pressure (hPa), humidity (%) and sunshine duration (min) between 09:00 a.m. and 04:00 p.m. were obtained from official websites. A total of 560,731 marathon runners' records were available for analysis (342,799 men and 217,932 women). Pearson and Spearman correlation analyses were performed between the average running speed and the weather variables (temperature, pressure, humidity and sunshine). Ordinary Least Squares (OLS) regressions were also performed. The runner´s records were classified into four performance groups (all runners, top 100, top 10 and top 3) for comparison. Differences in running speed between the four performance groups were statistically significant (p < 0.05) for both men and women. Pearson (linear) correlation indicated a weak and positive association with humidity in the top 10 (r = 0.16) and top 3 (r = 0.13) performance groups that the running speed of the elite runners was positively correlated with humidity. Regarding sunshine duration, there was a weak and positive correlation with the running speed of the elite groups (r = 0.16 in the top 10 and r = 0.2 in the top 3). Spearman correlation (non-linear) identified a weak but negative correlation coefficient with temperature in all runners’ groups. Also, non-linear positive correlation coefficients with humidity and sunshine can be observed in the Spearman matrixes. A Multivariate Ordinary Least Squares (OLS) regression analysis showed no predictive power of weather factors. For elite runners competing in the ‘New York City Marathon’ between 1999 and 2019, the main findings were that elite runners became faster with increasing humidity and sunshine duration while overall runners became slower with increasing temperature, increasing humidity and sunshine duration. Weather factors affected running speed and results but did not provide a significant predictive influence on performance