High-level programming of stencil computations on multi-GPU systems using the SkelCL library

The implementation of stencil computations on modern, massively parallel systems with GPUs and other accelerators currently relies on manually-tuned coding using low-level approaches like OpenCL and CUDA. This makes development of stencil applications a complex, time-consuming, and error-prone task. We describe how stencil computations can be programmed in our SkelCL approach that combines high-level programming abstractions with competitive performance on multi-GPU systems. SkelCL extends the OpenCL standard by three high-level features: 1) pre-implemented parallel patterns (a.k.a. skeletons); 2) container data types for vectors and matrices; 3) automatic data (re)distribution mechanism. We introduce two new SkelCL skeletons which specifically target stencil computations – MapOverlap and Stencil – and we describe their use for particular application examples, discuss their efficient parallel implementation, and report experimental results on systems with multiple GPUs. Our evaluation of three real-world applications shows that stencil code written with SkelCL is considerably shorter and offers competitive performance to hand-tuned OpenCL code

Introducing Parallelism to the Ranges TS

The current interface provided by the C++17 parallel algorithms poses some limitations with respect to parallel data access and heterogeneous systems, such as personal computers and server nodes with GPUs, smartphones, and embedded System on a Chip chipsets. In this paper, we present a summary of why we believe the Ranges TS solves these problems, and also improves both programmability and performance on heterogeneous platforms. The complete paper has been submitted to WG21 for consideration, and here we present a summary of the changes proposed alongside new performance results. To the best of our knowledge, this is the first paper presented to WG21 that unifies the Ranges TS with the parallel algorithms introduced in C++17. Although there are various points of intersection, we will focus on the composability of functions, and the benefit that this brings to accelerator devices via kernel fusion

Preparativne modifikacije askomicina. V. Dobivanje novih derivata pomoću zamjene cikloheksilvinilidenske podjedinice

Starting from the easily accessible 24-O-tert-butyldimethylsilyl-22(R)-dihydro-28-oxoascomycin, methodologies that allow replacement of the cyclohexylvinylidene moiety of ascomycin by various other substituents are described. In addition, a so far unknown reactivity of the masked tricarbonyl moiety of ascomycin towards a stabilized Wittig reagent is reported.Opisani su postupci koji počinju s lako pristupačnim 25-O-tert-butildimetilsilil-22(R)-dihidro-28-oksoaskomicinom i omogućuju zamjenu askomicinske cikloheksilvinilidenske podjedinice različitim substituentima

Enhanced thrombin generation in patients with cirrhosis-induced coagulopathy

BACKGROUND: Prothrombin time (PT) and the international normalized ratio (INR) are still routinely measured in patients with liver cirrhosis to 'assess' their bleeding risk despite the lack of correlation with the two. Thrombin generation (TG) assays are global assays of coagulation that are showing promise in assessing bleeding and thrombosis risks. AIM: To study the relationship between the INR and TG profiles in cirrhosis-induced coagulopathy. METHODS: Seventy-three patients with cirrhosis were studied. All TG parameters were compared with those from a normal control group. Contact activation was prevented using corn trypsin inhibitor. TG was also assayed in the presence of Protac(®). The endogenous thrombin potential (ETP) ratio was derived by dividing the ETP with Protac® by the ETP without Protac®. RESULTS: The INR (mean 1.7) did not correlate with the ETP and the velocity of TG (P > 0.05). There was no difference between the lag time and ETP of the two groups (P > 0.05). The velocity of TG was increased in cirrhosis (67.95 ± 34.8 vs. 45.05 ± 25.9 nM min⁻¹ ; P = 0.016) especially in patients with INRs between 1.21 and 2.0. Both the ETP with Protac(®) and the ETP ratio were increased in cirrhosis (mean 1074 ± 461.4 vs. 818 ± 357.9 nM min, P = 0.004 and 0.80 ± 0.21 vs. 0.44 ± 0.15, P ≤ 0.0001, respectively). CONCLUSION: Despite a raised INR, TG parameters are consistent with a hypercoagulable profile in cirrhosis-related coagulopathy. This confirms that the PT or INR should not be used to assess bleeding risk in these patients, and other parameters, such as TG, need to be explored as clinical markers of coagulopathy

Advances in the management of male infertility

Male infertility can be treated by surgical procedures (e.g., varicocelectomy) or by administration of drugs if causal factors (e.g., seminal tract infections) are detected. In more severe cases, methods of assisted fertilization often have to be applied, but even these have only a limited success rate. Recent studies have demonstrated that disturbances of sperm DNA integrity (determined by the acridine orange test) can explain certain cases of fertilization failure and failure to achieve pregnancy following in vitro fertilisation with intracytoplasmic sperm injection. The evaluation of DNA integrity should be considered when diagnosing male infertility as it has been shown to be an independent factor and can be used as a supplement to standard semen analysis. Analysis of DNA integrity may, therefore, provide further information about altered male fertility and lead to administration of more appropriate therapy

Evaluation of reference values of standard semen parameters in fertile Egyptian men

The reference values of human semen, published in the WHO’s latest edition in 2010, were lower than those previously reported. The objective of this study was to evaluate reference values of standard semen parameters in fertile Egyptian men. This cross-sectional study included 240 fertile men. Men were considered fertile when their wives had recent spontaneous pregnancies with time to pregnancy (TTP) ≤12 months. The mean age of fertile men was 33.8 ± 0.5 years (range 20–55 years). The 5th percentiles (95% confidence interval) of macroscopic semen parameters were 1.5 ml for volume and 7.2 for pH. The 5th percentiles of microscopic parameters were 15 million/ ml for sperm concentration, 30 million per ejaculate for total sperm count, 50% for total motility, 40% for progressive motility, 62% for vitality, 4% for normal sperm forms and 0.1 million/ml for seminal leucocyte counts. In conclusion, fertile Egyptian men had higher reference values of sperm total motility, progressive motility and vitality, and lower reference values for total sperm counts as compared to those determined by the latest edition of the WHO laboratory manual in 2010. Other semen parameters were identical to those defined by the WHO 2010 manual

ISLA / IFLA course design: Principles and practical proposals for beginners' courses

This paper is a revised version of the one that appeared with many formal defects in the original publication.00-Abstract: Everybody involved in teaching modern languages will have observed that even adults can still have access to some kind of intuitive knowledge (Coppieters, R. 1987) when exposed naturally to a new language, and this is independent of the language taught and the age of the students (Kim, et al, 1997). Looking for a theoretical explanation for these observational facts we came across an idea formulated by N. Chomsky (1965)1, who had claimed, in one of his few pronouncements on the relevance of his theories for language teaching, that the human mind must (automatically) possess ‘intuitive heuristics’, which, he argued, should be part of ‘teaching program(s) …. in such a way as to give free play to those creative principles that humans bring to the process of language learning’. In this paper we will try to show how this author’s ideas on competence (1965) and performance (1965, 1975, 1981) might serve as a general framework for foreign language teaching (A. Howatt, 1974, W. Littlewood, 1984 and Larsen-Freeman & Long, 1991) as they offer a quite plausible vision for explaining how different mental capacities cooperate when people use language for communication. Starting with a brief description of Chomsky’s competence model we will then analyse input, Chomsky’s central concept for language acquisition. This will be done under the perspective of the processes that can be supposed for comprehension and in terms of Relevance Theory (RT) (Sperber & Wilson, 1986). RT will then be reinterpreted, as Javier Garcia (2007) proposes, in the light of Michael Long's here-and-now principle (1983). In the last part, we will offer first a brief summary of the practical measures for classroom interaction developed during our long-term study, carried out between 2005 and 2015, measures that pretend to assure a natural like language processing in the classroom, and the paper concludes with a first brief summary of observational data on the results obtained so far. The principal conclusions proposed are twofold: With respect to theory, this paper claims that adults still seem to have a limited access to children’s Language Acquisition Device: the Adult-LAD. And, in practical terms: foreign language teaching should not begin with grammar teaching, but with immersion centred on communication

"Wissen was gerade gewünscht wird"

Die entscheidene Rolle der Motivation in Hinblick auf menschliches Verhalten und Handeln wurde von Forschern unterschiedlicher Disziplinen bestätigt. Großer Forschungsaufwand wurde betrieben, um die Motive für verschiedene Formen des Urlaubsverhaltens und die damit verbundenen Entscheidungsfindungsprozesse zu erkunden. Ein im Bezug auf Motivation sehr wichtiger Bereich rückte jedoch bislang nicht ins Blickfeld der Forscher. Um das Verhalten von Touristen verstehen und vorhersagen zu können ist es grundlegend zu wissen, welche Faktoren für die Änderung der Motivationslage im zeitlichen Verlauf verantwortlich sind. Dabei liegt der Fokus nicht auf der Veränderung über lange Sicht, sondern auf kurzfristigen, spontanen Veränderungen innerhalb weniger Stunden. Die hier vorgestellte Studie kann als erster Schritt in diese Richtung betrachtet werden. Ihr Ziel war es, die Motivationsdynamik von Städtetouristen in europäischen Metropolen zu erforschen. Die Studie (N=199) wurde unter Verwendung eines Onlinefragebogens durchgeführt. Es wurde angenommen, dass soziodemografische und tripografische Faktoren die Motivationsdynamik beeinflussen. Zudem wurde postuliert, dass Zusammenhänge zwischen den, im zeitlichen Verlauf, nacheinander gewählten Aktivitäten bestünden. Im Rahmen eines imaginären Städtetripps wurden die TeilnehmerInnen gebeten, ihre Urlaubsaktivitäten zu wählen. Die Ergebnisse zeigten einen signifikanten Zusammenhang zwischen bevorzugt gewählten Aktivitäten und bestimmten, eingrenzbaren Zeitabschnitten. Das Alter und der Lebenswandel einer Person erwiesen sich zusammen mit den Motiven für einen spezifischen Urlaub als wichtige Einflussfaktoren bezüglich Motivationsdynamik. Der Einfluss soziodemografischer und tripografischer Variablen wie beispielsweise Zusammensetzung der Reisegruppe oder Einkommen einer Person konnte nicht bestätigt werden. Dies wird auf die imaginäre Natur der untersuchten Reise zurückgeführt. Die Untersuchung der Motivationsdynamik in einem realen Setting mit ähnlichen, möglichst standardisierten Rahmenbedingungen wird als wichtige Aufgabe zukünftiger Forschungsarbeiten erachtet. Um der Komplexität des Themas möglichst gerecht zu werden wird ein multimethodisches Herangehen und ein weniger breiter Fokus vorgeschlagen. Zusammenfassend lässt sich sagen, dass die Ergebnisse gut mit vorangegangenen Forschungsergebnissen übereinstimmen. Sie fügen der vorhandenen Literatur bedeutsame Erkenntnisse hinzu und zeigen viele wichtige Ansatzpunkte und Gefahrenquellen auf, die in zukünftigen Forschungsarbeiten aufgegriffen und berücksichtig werden sollten.The importance of the construct of motivation, in the context of human behaviour and action, has been widely recognized among the researches of multiple disciplines. A lot of research has been conducted to investigate the motives associated with different forms of tourist behaviour and the decision-making-process. Still there is one very important issue, when it comes to understandig tourist behaviour, that hasn´t attracted the interest of researchers yet. To understand and forecast behaviour it is essential to know which factors are responsible for the shifts in the motivation over time, in the short view. This study represents a first step into this direction. The aim of the study was to explore the shifts in motivation of tourists in an urban european context. The present study (N=199) was conducted via an online-questionaire. It was assumed that sociodemografic and tripografic factors play an important role in the shifts of motivation. Further a relationship between the activities choosen over time was hypothesized. In an imaginary citytrip to an european metropolis, the participators were asked to select holiday activities. The results reveal significant relationships between the selection of preferred activities and specific time periodes, that could be narrowed down. Age and the way of life of a person and the motives, underlying a specific holiday, proved to be important factors when it comes to understanding changes in motivation. The important role of sociodemografic and tripografic factors like composition of the travelgroup oder income could not be replicated. The reason for this deviation from findings of past research is seen in the imaginary nature of the journey analysed. To investigate the shifts of motivation in a similar, but in vivo setting with standardized frame is seen as an important and seminal toehold for future research. To capture the complexity of the topic a multi-method approach and a narrower focus is proposed. Taken together the findings support past research, add important information and guide to important applications for future research