Aims: To investigate the gender differences in the patterns of cannabis use (CU), namely frequency, times of day, social context and methods and in their association with DSM-IV cannabis dependence. Methods: A sample of 3,904 students from German universities was recruited via an internet survey. Logistic regressions and associated areas under the ROC curve (AUC) were calculated among current cannabis users (at least once a month, n = 843). Results: CU using a water pipe was more often reported by males (50 vs. 34.6%). Usual CU ‘before going to sleep at night’ was more often reported by females (47.3 vs. 35.7%). Most CU patterns showed a similar association with DSM-IV cannabis dependence in both genders. The association of CU ‘with strangers’ was stronger in females (AUC 0.68 vs. AUC 0.56). Slightly different multiple models were found (females AUC 0.86, males AUC 0.77). Conclusions: There are considerable gender differences in the CU patterns and, thus, in the way CU functions. In the association of CU patterns with cannabis dependence, the similarities are rather great. Examining the CU patterns might make a considerable contribution to the better detection of high-risk population segments for prevention and early intervention in both genders. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Aims: To investigate the gender differences in the patterns of cannabis use (CU), namely frequency, times of day, social context and methods and in their association with DSM-IV cannabis dependence. Methods: A sample of 3,904 students from German universities was recruited via an internet survey. Logistic regressions and associated areas under the ROC curve (AUC) were calculated among current cannabis users (at least once a month, n = 843). Results: CU using a water pipe was more often reported by males (50 vs. 34.6%). Usual CU ‘before going to sleep at night’ was more often reported by females (47.3 vs. 35.7%). Most CU patterns showed a similar association with DSM-IV cannabis dependence in both genders. The association of CU ‘with strangers’ was stronger in females (AUC 0.68 vs. AUC 0.56). Slightly different multiple models were found (females AUC 0.86, males AUC 0.77). Conclusions: There are considerable gender differences in the CU patterns and, thus, in the way CU functions. In the association of CU patterns with cannabis dependence, the similarities are rather great. Examining the CU patterns might make a considerable contribution to the better detection of high-risk population segments for prevention and early intervention in both genders. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

In the Internet of Services (IoS) providers and consumers of services engage in business interactions on service marketplaces. Provisioning and consumption of services are regulated by service level agreements (SLA), which are negotiated between providers and consumers. Trading composite services requires the providers to manage the SLAs that are negotiated with the providers of atomic services and the consumers of the composition. The management of SLAs involves the negotiation and renegotiation of SLAs as well as their monitoring during service provisioning. The complexity of this task arises due to the fact that dependencies exist between the different services in a composition. Dependencies between services occur because the complex task of a composition is distributed between atomic services. Thus, the successful provisioning of the composite service depends on its atomic building blocks. At the same time, atomic services depend on other atomic services, e.g. because of data or resource requirements, or time relationships. These dependencies need to be considered for the management of composite service SLAs. This thesis aims at developing a management approach for dependencies between services in service compositions to support SLA management. Information about service dependencies is not explicitly available. Instead it is implicitly contained in the workflow description of a composite service, the negotiated SLAs of the composite service, and as application domain knowledge of experts, which makes the handling of this information more complex. Thus, the dependency management approach needs to capture this dependency information in an explicit way. The dependency information is then used to support SLA management in three ways. First of all dependency information is used during SLA negotiation the to ensure that the different SLAs enable the successful collaboration of the services to achieve the composite service goal. Secondly, during SLA renegotiation dependency information is used to determine which effects the renegotiation has on other SLAs. Finally, dependency information is used during SLA monitoring to determine the effects of detected violations on other services. Based on a literature study and two use cases from the logistics and healthcare domains different types of dependencies were analyzed and classified. The results from this analysis were used as a basis for the development of an approach to analyze and represent dependency information according to the different dependency properties. Furthermore, a lifecycle and architecture for managing dependency information was developed. In an iterative approach the different artifacts were implemented, tested based on two use cases, and refined according to the test results Finally, the prototype was evaluated with regard to detailed test cases and performance measurements were executed. The resulting dependency management approach has four main contributions. Firstly, it represents a holistic approach for managing service dependencies with regard to composite SLA management. It extends existing work by supporting the handling of dependencies between atomic services as well as atomic and composite services at design time and during service provisioning. Secondly, a semi-automatic approach to capturing dependency information is provided. It helps to achieve a higher degree of automation as compared to other approaches. Thirdly, a metamodel for representing dependency information for SLA management is shown. Dependency information is kept separately from SLA information to achieve a better separation of concerns. This facilitates the utilization of the dependency management functionality with different SLA management approaches. Fourthly, a dependency management architecture is presented. The design of the architecture ensures that the components can be integrated with different SLA management approaches. The test case based evaluation of the dependency management approach showed its feasibility and correct functioning in two different application domains. Furthermore, the performance evaluation showed that the automated dependency management tasks are executed within the range of milliseconds for both use cases. The dependency management approach is suited to support the different SLA management tasks. It supports the work of composite service providers by facilitating the SLA management of complex service compositions.

Objective: We present the prevalence and incidence rates of alcohol, nicotine, and illicit substance use, abuse, and dependence in a sample of German adolescents and young adults. Patterns of onset, cohort trends, and use of various substance classes are also analyzed. Method: A prospective longitudinal epidemiological study with a representative sample of adolescents and young adults (n = 3,021; baseline age range = 14–24 years) was conducted in Munich, Germany. Participants were assessed between 1995 and 1999 with the Munich-Composite International Diagnostic Interview. Results: Cumulative lifetime incidence (up to age 28) of any substance abuse or dependence was 43.8%, and 12-month prevalence of any substance abuse or dependence was 24.4%. The lifetime incidence of nicotine dependence was most frequent (24.8%), followed by alcohol abuse (19.3%) and alcohol dependence (9.2%); 61.7% endorsed the regular use of a substance for at least one circumscribed period during their lifetime. Age-specific incidence rates and age at onset of substance use disorders differed by age cohorts. Furthermore, nicotine dependence was significantly associated with illicit substance use disorders (HR = 2.6, 95% CI 1.7–4.0). An interactive relationship between age, age at onset of nicotine dependence, and subsequent onset of illicit substance use disorders was found. Conclusions: Since the baseline investigation in 1995, high incidence rates of substance use disorders and substance use have been observed in this young German sample. Especially younger cohorts report significantly earlier ages at onset of abuse and dependence. There also seems to be a trend towards a secondary age at onset peak of nicotine dependence after the onset of illicit drug use disorders. Further investigations are needed to study these patterns in younger samples. However, results emphasize the need for a combined prevention of illicit drugs and nicotine dependence. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Das bildgebende Prinzip des B-Flow® beruht nicht auf dem Dopplereffekt und hat dadurch Vorteile gegenüber den Dopplerverfahren bezüglich Winkelabhängigkeit, Orts- und Zeitauflösung. Das Verfahren zeichnet sich vor allem durch eine sehr wirklichkeitsgetreue überlagerungsfreie Echtzeitdarstellung von Blutfluss aus (WESKOTT 2000). Veterinärmedizinische Untersuchungen zum B-Flow® gibt es nur wenige (KIEFER et al. 2002) (KIEFER et al. 2004). Um Möglichkeiten und Grenzen dieses neuen Flussdetektionsverfahrens zu evaluieren, wurde folgende Untersuchung durchgeführt. Material und Methoden An verschiedenen Flussphantomen wird die Darstellbarkeit und Genauigkeit der Flussdarstellung vergleichend für den Farbdoppler, Powerdoppler und für B-Flow® untersucht. Der Einfluss von Untersuchungstiefe, Gefäßdurchmesser, Fluss-geschwindigkeit, Einfallswinkel der Schallwellen und Hämatokritwert auf Darstellbarkeit und Genauigkeit aller drei Verfahren wurde unter standardisierten Bedingungen analysiert. Die Flussphantome bestehen aus Plastikgefäßen, die mit Gewebeimitat aus Stärke, Gelatine und Wasser befüllt wurden und deren Innenraum mit jeweils einem Silikonschlauch des Innendurchmessers 1 mm, 2 mm beziehungsweise 5 mm in einem Winkel von 30°, 60° oder 90° durchzogen wurden. Durch die Schläuche wurde mit Hilfe einer Flusspumpe porcines Blut der Hämatokritstufen 10 %, 30 % und 60 % in vier verschiedenen Flussgeschwindigkeiten (0,4 m/s, 0,8 m/s, 1,2 m/s und 1,4 m/s) ge¬pumpt. Die Kombinationen dieser Parameter wurden jeweils in einer Tiefe von 3 cm, 5 cm und 7 cm untersucht. Die Darstellung erfolgte mit einem in seiner Position fixierten ML12 Matrixlinearschallkopf an einem Logiq 9 der Firma General Electrics. Aus den für jede Einstellungskombination erstellten Videosequenzen wurden Standbilder erstellt, im DICOM-Format gespeichert und mit einer für diesen Versuch entwickelten Software nachvermessen. Für die Beurteilung der Darstellbarkeit wurde ein Scoresystem eingeführt. Für die Beurteilung der Genauigkeit der Darstellung wurde aus der Differenz des gemessenen Lumens mit dem tatsächlichen Gefäßinnendurchmesser die absolute Abweichung in mm berechnet und bezüglich der Einflussgrößen ausgewertet. Ergebnisse Die Darstellbarkeit des B-Flow® war den Dopplerverfahren bei 5 mm Gefäßdurchmesser in 3 cm Tiefe überlegen. In Tiefen ab 5 cm ist die Aussagekraft des Verfahrens stark eingeschränkt. In 7 cm Tiefe ist B-Flow® nicht sinnvoll einsetzbar. Es konnte ein Einfluss des Einfallswinkels der Schallwellen sowohl für die Darstellbarkeit als auch für die Genauigkeit der Messung auf alle drei Verfahren festgestellt werden. Nur in 3 cm Tiefe bei einem Gefäßdurchmesser von 5 mm konnte bezüglich der Darstellbarkeit für den B-Flow® eine Winkelunabhängigkeit bestätigt werden. Der Hämatokritwert hatte bei allen drei Verfahren weder auf die Darstellbarkeit noch auf die Genauigkeit einen signifikanten Einfluss. Der Einfluss der Flussgeschwindigkeit auf die Darstellbarkeit war für alle drei Verfahren nicht signifikant. Auf die Genauigkeit konnte ein signifikanter Einfluss nachgewiesen werden. Je schneller der Fluss, desto größer werden die Werte für die absolute Abweichung. Für die Darstellung oberflächennaher Blutflüsse eignet sich B-Flow® sehr gut. Durch die weniger aufwändigen Einstellungsmodalitäten und die sehr detailgetreue Darstellung von Flussmustern ergänzt die Methode mit wesentlichen Zusatzinformationen die Dopplerverfahren.

The objectives of the community-based Early Developmental Stages of Psychopathology (EDSP) Study are described along with a detailed account of the overall design, special design features, sample characteristics and instruments used. The EDSP employed a prospective-longitudinal design to study substance use and other mental disorders in a representative population sample of 3,021 subjects aged 14–24 years (birth cohorts 1970–1981) at ‘baseline’ – the outset of the study. Two follow-up investigations were conducted after the baseline investigation covering an overall period of 3–4 years. Special design features are the linkage with a family supplement (EDSP-FS) as well as neurobiological laboratory studies of high-risk subjects.

Objectives: To determine risk factors of incident onset of use, abuse and dependence of cannabis in a community sample of adolescents and young adults. Methods: Risk factors were examined in a prospective longitudinal design across 4 years in a representative sample (N=2446) aged 14-24 at the outset of the study (EDSP). Patterns of DSM-IV defined cannabis use, abuse and dependence were assessed with the Composite International Diagnostic Interview (M-CIDI). Potential risk factors were assessed at baseline. Incident cannabis use, abuse and dependence at second follow-up (on average 42 months after baseline) were the main outcome measures in this study. Associations were analyzed with logistic and negative binomial regressions. Results: Using 11 of a total of 56 variables examined, the predictive value of the final multiple logistic regression for incident cannabis use was moderately good (area under the ROC curve=0.78). Cannabis use frequency was predicted in the final model by 18 variables, cannabis abuse by two variables in the younger subsample and nine factors in the older group, and dependence by eight variables (dependence: ROC curve area=0.97). Incident cannabis use was predicted mainly by availability of drugs, peers’ drug use, a more ‘positive’ attitude towards future drug use, and regular previous use of licit drugs, while cannabis dependence was predicted primarily by parental death before age 15, deprived socio-economic status, and baseline use of other illicit drugs. Conclusion: Different factors predict the onset or severity of cannabis use and the progression to abuse and dependence. In addition to well-documented risk factors such as peer group pressure, drug availability, and low self-esteem, findings suggest that family history (e.g. parental mental disorders, early parental death), and prior experiences with legal drugs play a significant role in the initiation of cannabis consumption and the transition to cannabis use disorders in adolescents and young adults. Findings suggest that early intervention and prevention might be improved by better targeted treatment.

Aim: To examine prospectively over a period of 4 years the profile of cannabis dependence and the risk of specific dependence criteria in a community sample of adolescents. Methods: A representative community sample of 2446 young adults aged 14–24 years at baseline was followed up over a period of 4 years. Frequency of use measures and of criteria for DSM-IV dependence were assessed by standardized diagnostic interview measures (CIDI). To explore the nature of this association, frequency of use and concomitant use of other psychoactive substances was considered. Results: 30% of the sample were cannabis users. Among all users 35% met at least one dependence criterion. Most frequently reported dependence criteria among all users were withdrawal (17%), tolerance (15%), loss of control (14%) and continued use despite a health problem (13%). Even without concomitant use of other illicit drugs, 22% of low frequency users and 81% of high frequency users met at least one dependence criterion. Symptom patterns were similar in high and low frequency users. The occurrence of a dependence syndrome or of specific dependence criteria could not be attributed to the use of other illicit drugs or to comorbid nicotine and alcohol dependence. Conclusions: Regular cannabis use in adolescence is associated with the development of a dependence syndrome. This association cannot be explained by the concomitant use of other illicit substances or by comorbid nicotine and alcohol dependence.

Die Arbeit gibt einen methodenkritischen Überblick über die in Deutschland vorliegenden Ergebnisse zur Prävalenz sowie Risikofaktoren von Substanzmißbrauch und -abhängigkeit (SMA). Es wird gezeigt, daß die vorliegenden epidemiologischen Studien unvollständig und methodisch unbefriedigend sind. Vor allem die fehlende Erfassung spezifischer diagnostischer Kriterien zur Ableitung klinisch relevanter Mißbrauchs- und Abhängigkeitsstörungen erschwert eine Interpretation der Ergebnisse der vorliegenden Repräsentativerhebungen. Diese geben zwar aussagekräftige populationsbezogene Informationen über die Häufigkeit und Verteilungsmuster von legalen und illegalen Substanzen, klinisch relevante Beurteilungsaspekte wie z.B. zu Schweregrad, Toleranz und Abstinenzproblemen sowie zu Einstieg und Verlauf der "Sucht"-Problematik fehlen jedoch vollständig. Dies trifft auch für Untersuchungen zu Risikofaktoren zu. Als ein durchgängiger Mangel wird ferner die Erfassungsmethodologie angesehen, die sich bislang fast ausschließlich auf Fragebögen oder Interviews stützt, über deren Reliabilität und Validität nur unzureichende psychometrische Daten vorliegen. / A critical review of prevalence and risk factor studies of substance abuse and dependence in Germany is presented. It is shown that currently available epidemiological data are incomplete due to the failure of instruments to allow for a detailed assessment of specific substance use disorders. The neglect of diagnostic criteria for clinically significant abuse and dependence disorders makes it especially difficult to draw conclusions about the results of representative surveys. Although the give clear population-related information about frequency and distribution patterns of legal and illegal substancees, relevant clinical data regarding aspects such as severity, tolerance, problems of abstinence, onset and course of abuse and dependence are completely lacking. This is also true of studies on risk factors. An additional problem is diagnostic assessment based almost exclusively on questionnaires and interviews whose reliability and validity have not been sufficiently established.

Objective: To determine incidence and patterns of natural course of ecstasy/stimulant/hallucinogen (ESH) use and disorders as well as cohort effects in a community sample of adolescents and young adults. Method: Cumulative incidence and patterns of ecstasy use and disorders were examined in a prospective longitudinal design (mean follow-up period=42 months) in a representative sample (N=2446) aged 14–24 years at the outset of the study. Patterns of DSM-IV defined ESH use, abuse and dependence were assessed with the Munich Composite International Diagnostic Interview (M-CIDI). Results: (1) Cumulative lifetime incidence for use of ESH at second follow-up: 9.1%, 1.0% for abuse, 0.6% for dependence; (2) men used and abused ESH more often than women; (3) the younger birth cohort (1977–81) tended to start earlier with substance (ab)use compared to the older birth cohort (1970–77); (4) use of ESH was associated with increasing rates of concomitant use of other licit and illicit drugs; (5) the majority of the lifetime ESH users without disorder had stopped to use these substances and not consumed them during the 12 months preceding the second follow-up; (6) those who had stopped to take ecstasy and related drugs at follow-up also took other illicit drugs less often than those who continued to consume ESH. Conclusions: Use of designer drugs is widespread in our sample, but the probability of developing use disorders is fairly low (1.6%). The majority of the ESH users stopped their use spontaneously in their twenties (80% of the prior users without disorder, 67% of the prior abusers), but 50% of those that once had fulfilled DSM-IV criteria of dependence continued to use these substances.