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Longitudinal studies reporting the association between cannabis use and developing depression provide mixed results. The objective of this study was to establish the extent to which different patterns of use of cannabis are associated with the development of depression using meta-analysis of longitudinal studies.
Peer-reviewed publications reporting the risk of developing depression in cannabis users were located using searches of EMBASE, Medline, PsychINFO and ISI Web of Science. Only longitudinal studies that controlled for depression at baseline were included. Data on several study characteristics, including measures of cannabis use, measures of depression and control variables, were extracted. Odds ratios (ORs) were extracted by age and length of follow-up.
After screening for 4764 articles, 57 articles were selected for full-text review, of which 14 were included in the quantitative analysis (total number of subjects = 76058). The OR for cannabis users developing depression compared with controls was 1.17 [95% confidence interval (CI) 1.05–1.30]. The OR for heavy cannabis users developing depression was 1.62 (95% CI 1.21–2.16), compared with non-users or light users. Meta-regression revealed no significant differences in effect based on age of subjects and marginal difference in effect based on length of follow-up in the individual studies. There was large heterogeneity in the number and type of control variables in the different studies.
Cannabis use, and particularly heavy cannabis use, may be associated with an increased risk for developing depressive disorders. There is need for further longitudinal exploration of the association between cannabis use and developing depression, particularly taking into account cumulative exposure to cannabis and potentially significant confounding factors.
We measure genetic variation in lifespan and fecundity at two food levels in 34 core lines of the Drosophila Genetic Reference Panel collection. Lines were significantly different from each other in lifespan and fecundity at both restricted and full food. There was a strong food-by-line interaction for the slope of age-specific mortality, fecundity and proportion of fertilized eggs, indicating the presence of genetic variation for the strength of the dietary restriction effect, likely to represent standing genetic variation in a natural population from which the lines used have originated. No trade-off between fecundity and lifespan manifested in life-history variation among inbred lines. Our data partially corroborate the recent proposition that availability of nutrient-free water eliminates the apparent dietary restriction at least in some conditions. Although flies on full food with water added had lifespan slightly higher than those without a water source, it was still significantly lower than that in flies on restricted food, with no indication of interaction. We fully corroborate the recently discovered effect of addition of essential amino acids to the medium: addition of 1·5 mM methionine to restricted food significantly increased fecundity without a measurable decrease in lifespan; addition of each of 10 essential amino acids increased fecundity and decreased females lifespan to the levels observed on full food, again with no evidence of line-by-food interactions. We propose a mechanistic hypothesis explaining the observed data, based on the assumption that food consumption by flies is adjusted according to flies’ saturation in water and methionine.
Mumps outbreaks in recent years have given rise to questions about the effectiveness of the mumps vaccine. This study examined the epidemiological data from a recent mumps outbreak in Israel and from outbreaks in other countries with high vaccination coverage, and considered whether long-established vaccination policies designed to protect against mumps are in need of revision. Of over 5000 case patients in the Israeli outbreak, half of whom were in the Jerusalem health district, nearly 40% were aged ⩾15 years and, of those whose vaccination status was known, 78% had been fully vaccinated for their age – features similar to those in recent mumps outbreaks in Europe and North America. The epidemiological and laboratory evidence suggests that many previously vaccinated adolescents and young adults are now susceptible to mumps because their vaccine-based immunity has waned. Booster vaccination programmes for those at high risk of infection during mumps outbreaks – particularly those in congregate living environments – merit priority consideration.
In order to extend the possibilities of doping of nitrides with activators of different valent and coordination states the complex A2B4C5 nitrides were investigated. The crystallochemical computer simulation of the new phosphor materials based on Mn, Ti and Eu-doped nitrides A2B4C5 has been made. Methods of synthesis of CaSiN2, and MgSiN2 have been developed, and X-ray diffraction analysis of these materials has been carried out. ESR and cathodoluminescent properties of MgSiN2, and CaSiN2 doped with manganese and europium have been studied.
The Commission home page <iau-c35.stsci.edu> is maintained by Claus Leitherer and contains general information on the Commission structure and activities, including links to stellar structure resources that were made available by the owners. The resources contain evolutionary tracks and isochrones from various groups, nuclear reaction, EOS, and opacity data as well as links to main astronomical journals. As a routine activity, the Organizing Committee has commented on and ranked proposals for several IAU sponsored meetings. Our Commission acted as one of the coordinating bodies of a Symposium held at the IAU XXVI General Assembly in Prague, August 2006, (IAU Symposium No. 239 Convection in Astrophysics, and participated in the organization of the following Joint Discussions: JD05 Calibrating the Top of the Stellar Mass-Luminosity Relation, JD06 Neutron Stars and Black Holes in Star Clusters, JD08 Solar and Stellar Activity Cycles, JD11 Pre-Solar Grains as Astrophysical Tools; JD14 Modelling Dense Stellar Systems; and JD17 Highlights of Recent Progress in the Seismology of the Sun and Sun-like Stars.
Using a longitudinal twin study of Moscow children, we have studied the development of psychometric intelligence during the transition from preschool (age 6) to school (age 7). Children were tested using the Wechsler Intelligence Scale for Children (WISC). Simplex models were applied to explore the relationship of different sources of phenotypic variance. The following sources of variation were considered: genetic effects, common or shared family environment and unique environment. At age 6, genetic influences were much greater than those of shared environment but the magnitude of genetic influences decreased and the magnitude of shared environment influences increased substantially by age 7.
A new representation for the characteristic function of the multivariate strictly geo-stable distribution is presented. The representation is appealing from a parametric viewpoint: its parameters have an intuitive probabilistic interpretation; and it is particularly useful for estimating the parameters of the geo-stable distribution.
A mathematical model based on queuing theory is used to study the dynamics of environmental influence on twin pairs. The model takes into consideration genetic factors and effects of non-shared environment. Histograms are exploited as base analysed characteristics, with the method of minimum chi-square yielding estimated characteristics. The proposed technique was applied to analysis of longitudinal data for MZ and DZ twins. It was shown that the same environment impact may yield different contributions to final variances of the IQ parameters under investigation. Magnitudes of these contributions depend on the genetic factor represented by distributions of an analysed parameter at the point of birth. Twin Research (2000) 3, 92–98.
In this paper we study some topics of interest to specialists in computer tomography. These are the following. (a) The Radon transform and its applications to computer tomography. (b) Problems of computer tomography with partially known data. Estimates of stability will be given for different types of distance in the space of probability distributions. We consider the problem with partially known tomographic data as a stability problem for appropriately chosen distances. This approach allows us to give a solution of the so-called computer tomography paradox. (c) The relation of quantum mechanics to computer tomography. An intriguing method for ‘measuring' wavefunctions by tomographic methods (CAT scans) opens a new approach to various problems in quantum mechanics. Using the method outlined for the solution of the computer tomography paradox, we derive inequalities that estimate the amount of information on the wavefunctions resulting from real CAT scans, i.e. CAT scans based on the finite number of measured marginals (projections) of the Wigner distributions. In conclusion, we propose a new version of the mathematical justification of CAT scans.