Computable de Finetti measures

We prove a computable version of de Finetti's theorem on exchangeable sequences of real random variables. As a consequence, exchangeable stochastic processes expressed in probabilistic functional programming languages can be automatically rewritten as procedures that do not modify non-local state. Along the way, we prove that a distribution on the unit interval is computable if and only if its moments are uniformly computable.Comment: 32 pages. Final journal version; expanded somewhat, with minor corrections. To appear in Annals of Pure and Applied Logic. Extended abstract appeared in Proceedings of CiE '09, LNCS 5635, pp. 218-23

Frequent k- ras -2 mutations and p16INK4Amethylation in hepatocellular carcinomas in workers exposed to vinyl chloride

Vinyl chloride (VC) is a know animal and human carcinogen associated with liver angiosarcomas (LAS) and hepatocellular carcinomas (HCC). In VC-associated LAS mutations of the K- ras -2 gene have been reported; however, no data about the prevalence of such mutations in VC associated HCCs are available. Recent data indicate K- ras -2 mutations induce P16 methylation accompanied by inactivation of the p16 gene. The presence of K- ras -2 mutations was analysed in tissue from 18 patients with VC associated HCCs. As a control group, 20 patients with hepatocellular carcinoma due to hepatitis B (n = 7), hepatitis C (n = 5) and alcoholic liver cirrhosis (n = 8) was used. The specific mutations were determined by direct sequencing of codon 12 and 13 of the K- ras -2 gene in carcinomatous and adjacent non-neoplastic liver tissue after microdissection. The status of p16 was evaluated by methylation-specific PCR (MSP), microsatellite analysis, DNA sequencing and immunohistochemical staining. All patients had a documented chronic quantitated exposure to VC (average 8883 ppmy, average duration: 245 months). K- ras -2 mutations were found in 6 of 18 (33%) examined VC-associated HCCs and in 3 cases of adjacent non-neoplastic liver tissue. There were 3 G → A point mutations in the tumour tissue. All 3 mutations found in non-neoplastic liver from VC-exposed patients were also G → A point mutations (codon 12- and codon 13-aspartate mutations). Hypermethylation of the 5′ CpG island of the p16 gene was found in 13 of 18 examined carcinomas (72%). Of 6 cancers with K- ras -2 mutations, 5 specimens also showed methylated p16. Within the control group, K- ras -2 mutation were found in 3 of 20 (15%) examined HCC. p16 methylation occurred in 11 out of 20 (55%) patients. K- ras -2 mutations and p16 methylation are frequent events in VC associated HCCs. We observed a K- ras -2 mutation pattern characteristic of chloroethylene oxide, a carcinogenic metabolite of VC. Our results strongly suggest that K- ras -2 mutations play an important role in the pathogenesis of VC-associated HCC. © 2001 Cancer Research Campaignhttp://www.bjcancer.co

Entwicklung und Darstellung von Strategieoptionen zur Behandlung von Saatgut im ökologischen Landbau

Zur Erzeugung gesunden Saatgutes steht im Öko-Landbau neben präventiven Maßnahmen eine Reihe verschiedener Saatgutbehandlungsverfahren zur Verfügung (physikalische Methoden, Pflanzenextrakte, Naturstoffe und Mikroorganismenpräparate), die jedoch für die zahlreichen, wichtigen Wirt/Pathogen-Kombinationen nicht hinreichend untersucht waren. Inhalt und Ziel dieses Verbundvorhabens war es, Erfolg versprechende, aber hinsichtlich Handhabbarkeit und Wirksamkeit bislang nicht ausreichend untersuchte Varianten zu überprüfen sowie Schwellenwerte zu ermitteln, die eine Saatgutbehandlung indizieren. Um eine schnelle Übertragbarkeit wirksamer Verfahren in die Praxis zu ermöglichen, wurden neben den physikalischen Verfahren überwiegend gelistete Pflanzenstärkungsmittel untersucht. Im ersten Untersuchungsschritt wurden Klimakammer- und Gewächshausversuche angelegt. Ansätze, die sich unter diesen Modellbedingungen für die Praxistestung als geeignet erwiesen, wurden in Feldversuchen (Projekt 03OE127/2) überprüft. Für wichtige Wirt/Pathogen-Kombinationen konnten unter Modellbedingungen Behandlungsvarianten mit guten Wirkungen ausgewählt werden, die keine bis geringe negative Auswirkungen auf die Keimfähigkeit hatten. Bei Sommergerste mit Netzflecken oder Streifenkrankheit sowie bei Haferflugbrand konnten nach Behandlung mit Heißwasser, LEBERMOOSER, Ethanol, Milsana flüssig, Serenade und/oder Cedomon gute bis sehr gute Wirkungen erreicht werden. An Winterweizen mit Fusarium spp., Stagonospora nodorum bzw. Schneeschimmel sowie Winterroggen mit Schneeschimmel wurde eine Wirkung vor allem durch FZB 53, Warm- oder Heißwasserbehandlung und LEBERMOOSER erreicht. Von den besonders schwer zu bekämpfenden Krankheiten wurden Anthraknose an Lupine und Ascochyta pisi an Erbse mit Feuchtheißluft reduziert, jedoch war die Wirkung nicht ausreichend

Computability of the Radon-Nikodym derivative

We study the computational content of the Radon-Nokodym theorem from measure theory in the framework of the representation approach to computable analysis. We define computable measurable spaces and canonical representations of the measures and the integrable functions on such spaces. For functions f,g on represented sets, f is W-reducible to g if f can be computed by applying the function g at most once. Let RN be the Radon-Nikodym operator on the space under consideration and let EC be the non-computable operator mapping every enumeration of a set of natural numbers to its characteristic function. We prove that for every computable measurable space, RN is W-reducible to EC, and we construct a computable measurable space for which EC is W-reducible to RN

Quantitative Coding and Complexity Theory of Compact Metric Spaces

Specifying a computational problem requires fixing encodings for input and output: encoding graphs as adjacency matrices, characters as integers, integers as bit strings, and vice versa. For such discrete data, the actual encoding is usually straightforward and/or complexity-theoretically inessential (up to polynomial time, say); but concerning continuous data, already real numbers naturally suggest various encodings with very different computational properties. With respect to qualitative computability, Kreitz and Weihrauch (1985) had identified ADMISSIBILITY as crucial property for 'reasonable' encodings over the Cantor space of infinite binary sequences, so-called representations [doi:10.1007/11780342_48]: For (precisely) these does the sometimes so-called MAIN THEOREM apply, characterizing continuity of functions in terms of continuous realizers. We rephrase qualitative admissibility as continuity of both the representation and its multivalued inverse, adopting from [doi:10.4115/jla.2013.5.7] a notion of sequential continuity for multifunctions. This suggests its quantitative refinement as criterion for representations suitable for complexity investigations. Higher-type complexity is captured by replacing Cantor's as ground space with Baire or any other (compact) ULTRAmetric space: a quantitative counterpart to equilogical spaces in computability [doi:10.1016/j.tcs.2003.11.012]

A CDCL-style calculus for solving non-linear constraints

In this paper we propose a novel approach for checking satisfiability of non-linear constraints over the reals, called ksmt. The procedure is based on conflict resolution in CDCL style calculus, using a composition of symbolical and numerical methods. To deal with the non-linear components in case of conflicts we use numerically constructed restricted linearisations. This approach covers a large number of computable non-linear real functions such as polynomials, rational or trigonometrical functions and beyond. A prototypical implementation has been evaluated on several non-linear SMT-LIB examples and the results have been compared with state-of-the-art SMT solvers.Comment: 17 pages, 3 figures; accepted at FroCoS 2019; software available at <http://informatik.uni-trier.de/~brausse/ksmt/

Radiofrequency applicator concepts for simultaneous MR imaging and hyperthermia treatment of glioblastoma multiforme: a 298 MHz(7.0 Tesla) thermal magnetic resonancesimulation study

Glioblastoma multiforme is the most frequent and most aggressive malignant brain tumor with de facto no long term curation by the use of current multimodal therapeutic approaches. The efficacy of brachytherapy and enhancing interstitial hyperthermia has been demonstrated. RF heating at ultrahigh fields (B0=7.0T, f=298MHz) has the potential of delivering sufficiently large thermal dosage for hyperthermia of relatively large tumor areas. This work focuses on electromagnetic field (EMF) simulations and provides realistic applicator designs tailored for simultaneous RF heating and MRI. Our simulations took advantage of target volumes derived from patient data, and our preliminary results suggest that RF power can be focused to both a small tumor area and a large clinical target volume

Mechanism of Preconditioning by Isoflurane in Rabbits: A Direct Role for Reactive Oxygen Species

LARGE quantities of reactive oxygen species (ROS) released during reperfusion after coronary artery occlusion damage proteins responsible for intracellular homeostasis, produce tissue injury, depress contractile function, and increase myocardial infarct size. In contrast, small quantities of ROS may exert beneficial effects during ischemia and reperfusion when released before a prolonged ischemic event. ROS derived from mitochondria during a brief ischemic episode produce preconditioning. Free radical scavengers administered during ischemic preconditioning (IPC) markedly attenuate the protective effect of the preconditioning stimulus on infarct size. These data suggest that IPC is mediated in part by small quantities of ROS released during preconditioning. Volatile anesthetics protect myocardium against infarction through a signal transduction pathway that includes adenosine type 1 receptors, protein kinase C, inhibitory guanine regulatory proteins, and mitochondrial and sarcolemmal adenosine triphosphate-regulated potassium (KATP) channels. A recent investigation by Müllenheim et al . provides compelling evidence that ROS also mediate myocardial protection produced by volatile anesthetics. We sought to confirm and extend these important results by examining the hypothesis that ROS scavengers inhibit isoflurane-induced protection against irreversible ischemic injury. We further tested the hypothesis that isoflurane directly generates ROS in rabbit ventricular myocardium in vivo using a confocal microscopic technique combined with the superoxide anion-specific fluorescent probe dihydroethidium

Physiological concentrations of bile acids down-regulate agonist induced secretion in colonic epithelial cells

In patients with bile acid malabsorption, high concentrations of bile acids enter the colon and stimulate Cl− and fluid secretion, thereby causing diarrhoea. However, deoxycholic acid (DCA), the predominant colonic bile acid, is normally present at lower concentrations where its role in regulating transport is unclear. Thus, the current study set out to investigate the effects of physiologically relevant DCA concentrations on colonic epithelial secretory function. Cl− secretion was measured as changes in short-circuit current across voltage-clamped T84 cell monolayers. At high concentrations (0.5–1 mM), DCA acutely stimulated Cl− secretion but this effect was associated with cell injury, as evidenced by decreased transepithelial resistance (TER) and increased lactate dehydrogenase (LDH) release. In contrast, chronic (24 hrs) exposure to lower DCA concentrations (10–200 μM) inhibited responses to Ca2+ and cAMP-dependent secretagogues without altering TER, LDH release, or secretagogue-induced increases in intracellular second messengers. Other bile acids – taurodeoxycholic acid, chenodeoxycholic acid and cholic acid – had similar antisecretory effects. DCA (50 μM) rapidly stimulated phosphorylation of the epidermal growth factor receptor (EGFr) and both ERK and p38 MAPKs (mitogen-activated protein kinases). The EGFr inhibitor, AG1478, and the protein synthesis inhibitor, cycloheximide, reversed the antisecretory effects of DCA, while the MAPK inhibitors, PD98059 and SB203580, did not. In summary, our studies suggest that, in contrast to its acute prosecretory effects at pathophysiological concentrations, lower, physiologically relevant, levels of DCA chronically down-regulate colonic epithelial secretory function. On the basis of these data, we propose a novel role for bile acids as physiological regulators of colonic secretory capacity