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Considerable evidence suggests that genetic factors combine with environmental influences to impact on the development of aggressive behavior. A genetic variant that has repeatedly been reported to render individuals more sensitive to the presence of adverse experiences, including stress exposure during fetal life, is the seven-repeat allele of the dopamine D4 receptor (DRD4) gene.
The present investigation concentrated on the interplay of prenatal maternal stress and DRD4 genotype in predicting self-reported aggression in young adults. As disruption of the hypothalamic-pituitary-adrenal system has been discussed as a pathophysiological pathway to aggression, cortisol stress reactivity was additionally examined.
As part of an epidemiological cohort study, prenatal maternal stress was assessed by maternal interview 3 months after childbirth. Between the ages of 19 and 23 years, 298 offspring (140 males, 158 females) completed the Young Adult Self-Report to measure aggressive behavior and were genotyped for the DRD4 gene. At 19 years, 219 participants additionally underwent the Trier Social Stress Test to determine cortisol reactivity.
Extending earlier findings with respect to childhood antisocial behavior, the results revealed that, under conditions of higher prenatal maternal stress, carriers of the DRD4 seven-repeat allele displayed more aggression in adulthood (p = 0.032). Moreover, the same conditions which seemed to promote aggression were found to predict attenuated cortisol secretion (p = 0.028).
This is the first study to indicate a long-term impact of prenatal stress exposure on the cortisol stress response depending on DRD4 genotype.
We present a data set of images of the gravitationally lensed quasar Q2237+0305, that was obtained at the Apache Point Observatory (APO) between June 1995 and January 1998. Although the images were taken under variable, often poor seeing conditions and with coarse pixel sampling, photometry is possible for the two brighter quasar images A and B with the help of exact quasar image positions from HST observations. We obtain a light curve with 73 data points for each of the images A and B. There is evidence for a long (ga 100 day) brightness peak in image A in 1996 with an amplitude of about 0.4 to 0.5 mag (relative to 1995), which indicates that microlensing has been taking place in the lensing galaxy. Image B does not vary much over the course of the observation period. The long, smooth variation of the light curve is similar to the results from the OGLE monitoring of the system (Wozniak et al. cite{Wozniak00}). Based on observations obtained with the Apache Point Observatory 3.5-meter telescope, which is owned and operated by the Astrophysical Research Consortium.
To address one of the central questions of plate tectonics-How do large transform systems work and what are their typical features?-seismic investigations across the Dead Sea Transform (DST), the boundary between the African and Arabian plates in the Middle East, were conducted for the first time. A major component of these investigations was a combined reflection/ refraction survey across the territories of Palestine, Israel and Jordan. The main results of this study are: (1) The seismic basement is offset by 3-5 km under the DST, (2) The DST cuts through the entire crust, broadening in the lower crust, (3) Strong lower crustal reflectors are imaged only on one side of the DST, (4) The seismic velocity sections show a steady increase in the depth of the crust-mantle transition (Moho) from 26 km at the Mediterranean to 39 km under the Jordan highlands, with only a small but visible, asymmetric topography of the Moho under the DST. These observations can be linked to the left-lateral movement of 105 km of the two plates in the last 17 Myr, accompanied by strong deformation within a narrow zone cutting through the entire crust. Comparing the DST and the San Andreas Fault (SAF) system, a strong asymmetry in subhorizontal lower crustal reflectors and a deep reaching deformation zone both occur around the DST and the SAF. The fact that such lower crustal reflectors and deep deformation zones are observed in such different transform systems suggests that these structures are possibly fundamental features of large transform plate boundaries
In silicate glasses and melts, water acts according to two main processes. First, it can be dissolved in high temperature/high pressure melts. Second, it constitutes a weathering agent on the glass surface. A number of in-situ x- ray absorption fine structure (XAFS) studies for Fe, Ni, Zr, Th and U show that the more charged cations (Zr, Nb, Mo, Ta, Sn, Th and U) are little affected by the presence of dissolved water in the melt. In contrast, divalent iron and nickel are highly sensitive to the presence of water, which enhance nucleation processes, for example, of phyllosilicates at the angstrom-scale. Such information provides additional constraints on the role of water deep in the Earth, particularly in magmatology. By contrast, the weathering of glass surfaces by water can be studied from a durability perspective. Experimental weathering experiments Of nuclear waste glasses performed in the laboratory show a variety of surface enrichments (carbon, chlorine, alkalis, iron) after exposure to atmospheric fluids and moisture. Mn-, and Fe-surface enrichments of analogous glasses of the XIVth century are related to the formation of Mn and Fe oxy/ hydroxides on the surface. The impact on the glass darkening is considered in terms of urban pollution and mass tourism
There is ample evidence that the early initiation of alcohol use is a risk factor for the development of later alcohol-related problems. The purpose of the current study was to examine whether this association can be explained by indicators of a common underlying susceptibility or whether age at drinking onset may be considered as an independent predictor of later drinking behavior, suggesting a potential causal relationship. Participants were drawn from a prospective cohort study of the long-term outcomes of early risk factors followed up from birth onwards. Structured interviews were administered to 304 participants to assess age at first drink and current drinking behavior. Data on risk factors, including early family adversity, parental alcohol use, childhood psychopathology and stressful life events, were repeatedly collected during childhood using standardized parent interviews. In addition, information on genotype was considered. Results confirmed previous work demonstrating that hazardous alcohol consumption is related to early-adolescent drinking onset. A younger age of first drink was significantly predicted by 5-HTTLPR genotype and the degree of preceding externalizing symptoms, and both factors were related to increased consumption or harmful alcohol use at age 19. However, even after controlling for these potential explanatory factors, earlier age at drinking onset remained a strong predictor of heavy alcohol consumption in young adulthood. The present longitudinal study adds to the current literature indicating that the early onset - adult hazardous drinking association cannot solely be attributed to shared genetic and psychopathologic risk factors as examined in this study.
Background: Clock genes govern circadian rhythms and shape the effect of alcohol use on the physiological system. Exposure to severe negative life events is related to both heavy drinking and disturbed circadian rhythmicity. The aim of this study was 1) to extend previous findings suggesting an association of a haplotype tagging single nucleotide polymorphism of PER2 gene with drinking patterns, and 2) to examine a possible role for an interaction of this gene with life stress in hazardous drinking.
Methods: Data were collected as part of an epidemiological cohort study on the outcome of early risk factors followed since birth. At age 19 years, 268 young adults (126 males, 142 females) were genotyped for PER2 rs56013859 and were administered a 45-day alcohol timeline follow-back interview and the Alcohol Use Disorders Identification Test (AUDIT). Life stress was assessed as the number of severe negative life events during the past four years reported in a questionnaire and validated by interview.
Results: Individuals with the minor G allele of rs56013859 were found to be less engaged in alcohol use, drinking at only 72% of the days compared to homozygotes for the major A allele. Moreover, among regular drinkers, a gene x environment interaction emerged (p = .020). While no effects of genotype appeared under conditions of low stress, carriers of the G allele exhibited less hazardous drinking than those homozygous for the A allele when exposed to high stress.
Conclusions: These findings may suggest a role of the circadian rhythm gene PER2 in both the drinking patterns of young adults and in moderating the impact of severe life stress on hazardous drinking in experienced alcohol users. However, in light of the likely burden of multiple tests, the nature of the measures used and the nominal evidence of interaction, replication is needed before drawing firm conclusions.
Galaxies are surrounded by large reservoirs of gas, mostly hydrogen, that are fed by inflows from the intergalactic medium and by outflows from galactic winds. Absorption-line measurements along the lines of sight to bright and rare background quasars indicate that this circumgalactic medium extends far beyond the starlight seen in galaxies, but very little is known about its spatial distribution. The Lyman-alpha transition of atomic hydrogen at a wavelength of 121.6 nanometres is an important tracer of warm (about 104 kelvin) gas in and around galaxies, especially at cosmological redshifts greater than about 1.6 at which the spectral line becomes observable from the ground. Tracing cosmic hydrogen through its Lyman-a emission has been a long-standing goal of observational astrophysics(1-3), but the extremely low surface brightness of the spatially extended emission is a formidable obstacle. A new window into circumgalactic environments was recently opened by the discovery of ubiquitous extended Lyman-alpha emission from hydrogen around high-redshift galaxies(4,5). Such measurements were previously limited to especially favourable systems(6-8) or to the use of massive statistical averaging(9,10) because of the faintness of this emission. Here we report observations of low-surface-brightness Lyman-alpha emission surrounding faint galaxies at redshifts between 3 and 6. We find that the projected sky coverage approaches 100 per cent. The corresponding rate of incidence (the mean number of Lyman-alpha emitters penetrated by any arbitrary line of sight) is well above unity and similar to the incidence rate of high-column-density absorbers frequently detected in the spectra of distant quasars(11-14). This similarity suggests that most circumgalactic atomic hydrogen at these redshifts has now been detected in emission.