Multivariate p-dic L-function

We construct multivariate p-adic L-function in the p-adic number fild by using Washington method.Comment: 9 page

Microscopic Surface Structure of Liquid Alkali Metals

We report an x-ray scattering study of the microscopic structure of the surface of a liquid alkali metal. The bulk liquid structure factor of the eutectic K67Na33 alloy is characteristic of an ideal mixture, and so shares the properties of an elemental liquid alkali metal. Analysis of off-specular diffuse scattering and specular x-ray reflectivity shows that the surface roughness of the K-Na alloy follows simple capillary wave behavior with a surface structure factor indicative of surface induced layering. Comparison of thelow-angle tail of the K67Na33 surface structure factor with the one measured for liquid Ga and In previously suggests that layering is less pronounced in alkali metals. Controlled exposure of the liquid to H2 and O2 gas does not affect the surface structure, indicating that oxide and hydride are not stable at the liquid surface under these experimental conditions.Comment: 12 pages, 3 figures, published in Phys. Rev.

Reasoning deficits among illicit drug users are associated with aspects of cannabis use

Background. Deficits in deductive reasoning have been observed among ecstasy/polydrug users. The present study seeks to investigate dose-related effects of specific drugs and whether these vary with the cognitive demands of the task. Methods. One hundred and five participants (mean age 21.33, S.D. 3.14; 77 females, 28 males) attempted to generate solutions for eight one-model syllogisms and one syllogism for which there was no valid conclusion (NVC). All of the one model syllogisms generated at least one valid conclusion and six generated two valid conclusions. In these six cases one of the conclusions was classified as common and the other as non-common. Results. The number of valid common inferences was negatively associated with aspects of short term cannabis use and with measures of IQ. The outcomes observed were more than simple post intoxication effects since cannabis use in the 10 days immediately before testing was unrelated to reasoning performance. Following adjustment for multiple comparisons, the number of non-common valid inferences was not significantly associated with any of the drug use measures. Conclusions. Recent cannabis use appears to impair the processes associated with generating valid common inferences while not affecting the production of non-common inferences. It is possible, therefore, that the two types of inference may recruit different executive resources which may differ in their susceptibility to cannabis-related effects

Ecstasykonsumenten: Neurokognitive und funktionelle Problemkonstellationen und Ansätze zu spezifischen Frühinterventionen

Hintergrund: In den letzten Jahren ist zunehmend deutlich geworden, dass Konsumenten von Ecstasy sich hinsichtlich Gebrauchsmuster und -kontext wie auch Spontanverlauf, Risiken und Konsequenzen von Konsumenten anderer legaler und illegaler Substanzen unterscheiden und möglicherweise eine recht eigenständige Gruppe darstellen. Diese eigenständige Gruppe wird im angelsächsischen Raum zum Teil auch als club drug user bezeichnet. Alarmierend waren die Vermutungen aus Voruntersuchungen, dass club drug-Konsumenten auch nach dem Konsum geringer Mengen von Ecstasy bemerkenswerte und möglicherweise überdauernde neurobiologische Veränderungen mit assoziierten kognitiven Beeinträchtigungen und Störungen aufzeigen. Dies stellt an sich eine mögliche Gefährdung der Konsumenten dar, zusätzlich wiederum können kognitive Veränderungen auch Einfluss nehmen auf den Verlauf des weiteren Suchtmittelkonsums und den Erfolg von Interventionen. Ziel: In der MAYA-Studie (Munich Assessment of Young Adults) werden an einer epidemiologischen Bevölkerungsstichprobe junger Erwachsener (Stichprobe A) sowie an einer klinischen Stichprobe von Ecstasy-Konsumenten (Stichprobe B) die Art und das Ausmaß kognitiver Störungen und Defizite in Abhängigkeit von Gebrauchsmustern und anderen Einflussfaktoren untersucht. Bei der Stichprobe A handelt es sich um ein Subsample der EDSPStudie. Zusätzlich zu den bereits erhobenen Charakterisierungen werden spezifische neurokognitive Maße (vor allem Aufmerksamkeit, Gedächtnis und exekutive Funktionen) und Fragebögen (Impulsivität, BDI, STAI etc.) erhoben. Die Probanden erhalten weiterhin ein Screening mit dem neu eingeführten Instrument WHO ASSIST (Alcohol, Smoking and Substance Involvement Screening Test). Wenn indiziert, wird eine Intervention im Sinne eines Motivational Enhancement durchgeführt. Initiale Auswirkungen werden in einem Telefoninterview sechs Wochen später überprüft. Ergebnisse: Die vorläufigen Ergebnisse beruhen auf einer Teilstichprobe. Insgesamt handelte es sich eher um Konsumenten mit geringgradigem bis moderaten Konsum. Dennoch ließen sich Unterschiede zwischen den Konsumentengruppen (Ecstasy, Cannabis, Alkohol) und den Nichtkonsumenten erkennen. Die Konsumenten von Ecstasy unterschieden sich am ausgeprägtesten von den Kontrollen. Die sich bisher abzeichnenden Unterschiede bei Aufmerksamkeit, Gedächtnis und exekutiven Funktionen scheinen bei der Gedächtnis- und Merkfähigkeit am ausgeprägtesten zu sein. Bei diesen vorläufigen Ergebnissen sind die Untersuchungsgruppen noch sehr heterogen und enthalten z.B. Probanden, die ihren Ecstasykonsum bereits wieder aufgegeben haben.Introduction: In recent years it has become increasingly evident that ecstasy users represent a group distinct from users of other drugs. This is based on consumption patterns, context of use, development of use patterns and other factors. This group of users might be considered "club drug users", given the overlap, similarity of use patterns and consumptions within the class of club drugs. In recent neurobiological research, alarming results have been reported, indicating that persistent neurotoxic effects with concomitant cognitive problems may be induced by ecstasy consumption. Methods: In the Munich Assessment of Young Adults Study (MAYA) two samples of ecstasy users are investigated. Sample A is a sample of users drawn from an ongoing epidemiological longitudinal study of young adults in Munich. Sample B is an additional clinical sample. Both samples are characterized extensively and are neuropsychologically tested for attention, memory and executive functioning. A screening for harmful use is conducted with the German version of the WHO ASSIST (Alcohol, Smoking and Substance Involvement Screening Test). A Motivational Enhancement Intervention is applied when harmful use is detected. With a telephone interview the intervention's initial effect is assessed. Results: Initial results are based on a small sample. Use within the tested population is low to moderate. Still significant differences in attention, memory, and executive functioning could be detected with the current testing. Ecstasy users almost consistently showed the lowest cognitive functioning. The one difference is that ecstasy users were significantly faster in finger tapping and reaction. Note that the results are preliminary. The sample is heterogeneous, including both current and former users. Firmer results will be reported with the full sample size, allowing to further elucidate subgroups and interactions

Effects of ecstasy/polydrug use on memory for associative information

Rationale Associative learning underpins behaviours that are fundamental to the everyday functioning of the individual. Evidence pointing to learning deficits in recreational drug users merits further examination. Objectives A word pair learning task was administered to examine associative learning processes in ecstasy/polydrug users. Methods After assignment to either single or divided attention conditions, 44 ecstasy/polydrug users and 48 non-users were presented with 80 word pairs at encoding. Following this, four types of stimuli were presented at the recognition phase: the words as originally paired (old pairs), previously presented words in different pairings (conjunction pairs), old words paired with new words, and pairs of new words (not presented previously). The task was to identify which of the stimuli were intact old pairs. Results Ecstasy/ploydrug users produced significantly more false-positive responses overall compared to non-users. Increased long-term frequency of ecstasy use was positively associated with the propensity to produce false-positive responses. It was also associated with a more liberal signal detection theory decision criterion value. Measures of long term and recent cannabis use were also associated with these same word pair learning outcome measures. Conjunction word pairs, irrespective of drug use, generated the highest level of false-positive responses and significantly more false-positive responses were made in the divided attention condition compared to the single attention condition. Conclusions Overall, the results suggest that long-term ecstasy exposure may induce a deficit in associative learning and this may be in part a consequence of users adopting a more liberal decision criterion value

Pseudo-regularly varying functions and generalized renewal processes

One of the main aims of this book is to exhibit some fruitful links between renewal theory and regular variation of functions. Applications of renewal processes play a key role in actuarial and financial mathematics as well as in engineering, operations research and other fields of applied mathematics. On the other hand, regular variation of functions is a property that features prominently in many fields of mathematics. The structure of the book reflects the historical development of the authors’ research work and approach – first some applications are discussed, after which a basic theory is created, and finally further applications are provided. The authors present a generalized and unified approach to the asymptotic behavior of renewal processes, involving cases of dependent inter-arrival times. This method works for other important functionals as well, such as first and last exit times or sojourn times (also under dependencies), and it can be used to solve several other problems. For example, various applications in function analysis concerning Abelian and Tauberian theorems can be studied as well as those in studies of the asymptotic behavior of solutions of stochastic differential equations. The classes of functions that are investigated and used in a probabilistic context extend the well-known Karamata theory of regularly varying functions and thus are also of interest in the theory of functions. The book provides a rigorous treatment of the subject and may serve as an introduction to the field. It is aimed at researchers and students working in probability, the theory of stochastic processes, operations research, mathematical statistics, the theory of functions, analytic number theory and complex analysis, as well as economists with a mathematical background. Readers should have completed introductory courses in analysis and probability theory.