An exactly solvable record model for rainfall

Daily precipitation time series are composed of null entries corresponding to dry days and nonzero entries that describe the rainfall amounts on wet days. Assuming that wet days follow a Bernoulli process with success probability $p$, we show that the presence of dry days induces negative correlations between record-breaking precipitation events. The resulting non-monotonic behavior of the Fano factor of the record counting process is recovered in empirical data. We derive the full probability distribution $P(R,n)$ of the number of records $R_n$ up to time $n$, and show that for large $n$, its large deviation form coincides with that of a Poisson distribution with parameter $\ln(p\,n)$. We also study in detail the joint limit $p \to 0$, $n \to \infty$, which yields a random record model in continuous time $t = pn$.Comment: 11 pages, 2 figures + 13 pages and 2 figures of supplemental materia

The words for 'star' in Indo-European and Semitic

This article brings together two fields: (1) the traditional study of the lexicon of Proto-Indo-European (including the material culture and belief system of the prehistoric speakers of Proto-Indo-European) and (2) the traditional study of the lexicon of Proto-Semitic (also including the material culture and belief system of the prehistoric speakers of Proto-Semitic). In particular, this paper deals with the words for 'star' in Indo-European and Semitic. The main proposals concerning their possible origin are evaluated, and the most probable proposal is highlighted. In both cases, the underlying meaning for the words for 'star' turns out to be something like 'the burning, glowing, shining thing or object'

L’absence maternelle, matrice de Cendrillon de Joël Pommerat

S’engager dans une réflexion sur l’œuvre de Joël Pommerat pose une première difficulté. L’artiste ne cesse en effet de mettre en évidence son goût pour la complexité, l’incertain, le trouble – pour reprendre le titre de l’ouvrage de Joëlle Gayot. Nous amorçons ici une entreprise paradoxale lors de laquelle nous chercherons à mettre en lumière certains aspects d’un spectacle, sans pour autant nous laisser aveugler par une trop grande clarté. Ce n’est pas un hasard si la compagnie de l’artiste..

Development of a statistical daily precipitation model and its application to precipitation records

In recent years, numerous record-breaking precipitation events have caused several deaths and high economic losses. However, current precipitation models do not adequately capture exceptionally high precipitation events. To address this problem, a new statistical daily precipitation model including several new aspects was developed. The model distinguishes between stratiform and convective precipitation, whereby the disaggregation of these two types of precipitation is based on SYNOP reports of 300 German weather stations. By combining a Weibull distribution with power law, a new probability distribution was derived and later implemented in the amount process. This four-parameter distribution improves the modelling of extreme precipitation amounts enormously and still delivers good results for small amounts. To take account of variability, a confined random walk was additionally implemented in the occurrence process of the model. The model was developed in a manner that allows universal use. By incorporating the elevation of a station and the time of the year as input parameters, the model was made applicable at any time and for any location in Germany. In a second step the model was applied to investigate daily precipitation records. For that, linear changes were implemented into the model. As result, a previously found decrease of records in the summer season can be explained by changes in the stratiform precipitation distribution. However, the decrease of precipitation records in the summer season is too low to rule out random processes as cause of this decrease. In contrast, the increase in the mean number of precipitation records in winter season cannot be reproduced with the developed model. A possible explanation for that is the neglect of spatial correlations in the amount process. An appropriate method for taking spatial correlations into account, could be a Copula approach

On the clustering of winter storm loss events over Germany

During the last decades, several windstorm series hit Europe leading to large aggregated losses. Such storm series are examples of serial clustering of extreme cyclones, presenting a considerable risk for the insurance industry. Clustering of events and return periods of storm series for Germany are quantified based on potential losses using empirical models. Two reanalysis data sets and observations from German weather stations are considered for 30 winters. Histograms of events exceeding selected return levels (1-, 2- and 5-year) are derived. Return periods of historical storm series are estimated based on the Poisson and the negative binomial distributions. Over 4000 years of general circulation model (GCM) simulations forced with current climate conditions are analysed to provide a better assessment of historical return periods. Estimations differ between distributions, for example 40 to 65 years for the 1990 series. For such less frequent series, estimates obtained with the Poisson distribution clearly deviate from empirical data. The negative binomial distribution provides better estimates, even though a sensitivity to return level and data set is identified. The consideration of GCM data permits a strong reduction of uncertainties. The present results support the importance of considering explicitly clustering of losses for an adequate risk assessment for economical applications

The Trusted Server: A secure computational environment for privacy compliant evaluations on plain personal data

A growing framework of legal and ethical requirements limit scientific and commercial evaluation of personal data. Typically, pseudonymization, encryption, or methods of distributed computing try to protect individual privacy. However, computational infrastructures still depend on human system administrators. This introduces severe security risks and has strong impact on privacy: system administrators have unlimited access to the computers that they manage including encryption keys and pseudonymization-tables. Distributed computing and data obfuscation technologies reduce but do not eliminate the risk of privacy leakage by administrators. They produce higher implementation effort and possible data quality degradation. This paper proposes the Trusted Server as an alternative approach that provides a sealed and inaccessible computational environment in a cryptographically strict sense. During operation or by direct physical access to storage media, data stored and processed inside the Trusted Server can by no means be read, manipulated or leaked, other than by brute-force. Thus, secure and privacy-compliant data processing or evaluation of plain person-related data becomes possible even from multiple sources, which want their data kept mutually secret

Intestinal S100/Calgranulin Expression in Cats with Chronic Inflammatory Enteropathy and Intestinal Lymphoma.

Diagnosing chronic inflammatory enteropathies (CIE) in cats and differentiation from intestinal lymphoma (IL) using currently available diagnostics is challenging. Intestinally expressed S100/calgranulins, measured in fecal samples, appear to be useful non-invasive biomarkers for canine CIE but have not been evaluated in cats. We hypothesized S100/calgranulins to play a role in the pathogenesis of feline chronic enteropathies (FCE) and to correlate with clinical and/or histologic disease severity. This retrospective case-control study included patient data and gastrointestinal (GI) tissues from 16 cats with CIE, 8 cats with IL, and 16 controls with no clinical signs of GI disease. GI tissue biopsies were immunohistochemically stained using polyclonal α-S100A8/A9 and α-S100A12 antibodies. S100A8/A9+ and S100A12+ cells were detected in all GI segments, with few significant differences between CIE, IL, and controls and no difference between diseased groups. Segmental inflammatory lesions were moderately to strongly correlated with increased S100/calgranulin-positive cell counts. Clinical disease severity correlated with S100A12+ cell counts in cats with IL (ρ = 0.69, p = 0.042) and more severe diarrhea with colonic lamina propria S100A12+ cells with CIE (ρ = 0.78, p = 0.021) and duodenal S100A8/A9+ cells with IL (ρ = 0.71, p = 0.032). These findings suggest a role of the S100/calgranulins in the pathogenesis of the spectrum of FCE, including CIE and IL