Childhood adversity is associated with poor mental and physical health outcomes across the life span. Alterations in the hypothalamic–pituitary–adrenal axis are considered a key mechanism underlying these associations, although findings have been mixed. These inconsistencies suggest that other aspects of stress processing may underlie variations in this these associations, and that differences in adversity type, sex, and age may be relevant. The current study investigated the relationship between childhood adversity, stress perception, and morning cortisol, and examined whether differences in adversity type (generalized vs. threat and deprivation), sex, and age had distinct effects on these associations. Salivary cortisol samples, daily hassle stress ratings, and retrospective measures of childhood adversity were collected from a large sample of youth at risk for serious mental illness including psychoses (n = 605, mean age = 19.3). Results indicated that childhood adversity was associated with increased stress perception, which subsequently predicted higher morning cortisol levels; however, these associations were specific to threat exposures in females. These findings highlight the role of stress perception in stress vulnerability following childhood adversity and highlight potential sex differences in the impact of threat exposures.

The role that vitamin D plays in pulmonary function remains uncertain. Epidemiological studies reported mixed findings for serum 25-hydroxyvitamin D (25(OH)D)–pulmonary function association. We conducted the largest cross-sectional meta-analysis of the 25(OH)D–pulmonary function association to date, based on nine European ancestry (EA) cohorts (n 22 838) and five African ancestry (AA) cohorts (n 4290) in the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium. Data were analysed using linear models by cohort and ancestry. Effect modification by smoking status (current/former/never) was tested. Results were combined using fixed-effects meta-analysis. Mean serum 25(OH)D was 68 (sd 29) nmol/l for EA and 49 (sd 21) nmol/l for AA. For each 1 nmol/l higher 25(OH)D, forced expiratory volume in the 1st second (FEV1) was higher by 1·1 ml in EA (95 % CI 0·9, 1·3; P<0·0001) and 1·8 ml (95 % CI 1·1, 2·5; P<0·0001) in AA (Prace difference=0·06), and forced vital capacity (FVC) was higher by 1·3 ml in EA (95 % CI 1·0, 1·6; P<0·0001) and 1·5 ml (95 % CI 0·8, 2·3; P=0·0001) in AA (Prace difference=0·56). Among EA, the 25(OH)D–FVC association was stronger in smokers: per 1 nmol/l higher 25(OH)D, FVC was higher by 1·7 ml (95 % CI 1·1, 2·3) for current smokers and 1·7 ml (95 % CI 1·2, 2·1) for former smokers, compared with 0·8 ml (95 % CI 0·4, 1·2) for never smokers. In summary, the 25(OH)D associations with FEV1 and FVC were positive in both ancestries. In EA, a stronger association was observed for smokers compared with never smokers, which supports the importance of vitamin D in vulnerable populations.

Using variational calculus, we investigate the time-dependent injection rate that minimises the growth of the Saffman–Taylor instability when a finite volume of fluid is injected in a finite time, $t_{f}$ , into a Hele-Shaw cell. We first consider a planar interface, and show that, with a constant viscosity ratio, the constant injection rate is optimal. When the viscosity of the displacing fluid, $\unicode[STIX]{x1D707}_{1}(t)$ , gradually increases over time, as may occur with a slowly gelling polymer solution, the optimal injection rate, $U^{\ast }(t)$ , involves a gradual increase in the flow rate with time. This leads to a smaller initial value of flow rate than the constant injection rate, finishing with a larger value. Such optimisation can lead to a substantial suppression of the instability as compared to the constant injection case if the characteristic gelling time is comparable to $t_{f}$ . In contrast, for either relatively slow or fast gelling, there is much less benefit in selecting the optimal injection rate, $U^{\ast }(t)$ , as compared to the constant injection rate. In the case of a constant injection rate from a point source, $Q$ , then with a constant viscosity ratio the fastest-growing perturbation on the radially spreading front involves axisymmetric modes whose wavenumber increases with time. Approximating the discrete azimuthal modes by a continuous distribution, we find the injection rate that minimises growth, $Q^{\ast }(t)$ . We find that there is a critical time for injection, $t_{f}^{\dagger }$ , such that if $t_{f}>t_{f}^{\dagger }$ then $Q^{\ast }(t)$ can be chosen so that the interface is always stable. This critical time emerges from the case with an injection rate given by $Q^{\ast }\sim t^{-1/3}$ . As the total injection time is reduced to values $t_{f}<t_{f}^{\dagger }$ , the system becomes progressively more unstable, and the optimal injection rate for an idealised continuous distribution of azimuthal modes asymptotes to a flow rate that increases linearly with time. As for the one-dimensional case, if the viscosity of the injection fluid gradually increases over time, then the optimal injection rate has a smaller initial value but gradually increases to larger values than for the analogous constant viscosity problem. If the displacing fluid features shear-thinning rheology, then the optimal injection rate involves a smaller flow rate at early times, although not as large a reduction as in the Newtonian case, and a larger flow rate at late times, although not as large an increase as in the Newtonian case.

The Einstein IPC observed the bright (5 mCrab) X-ray emitting BL Lac Object PKS 2155-304 on 1979 November 4th and 5th through 7th and on 1980 May 16th through 18th. A total of 17.4 hours were spent monitoring the source. Changes in intensity of between 10–50% are evident in the data for time scales of days and months. The source was constant to within 10% of the mean intensity on hourly time scales for all intervals of data except one. Repeated factor of 2 variations in intensity, occuring on 10–30 second time scales, were observed during the first 50 minutes of the 1979 Nov. 5th observation. These variations, however, were anticorrelated with variations seen in an adjacent background region. Concurrent MPC observations also failed to confirm the rapid changes, although they should have been readily detected. Thus, we conclude that the observed rapid variations are not intrinsic to the source, but originated in the IPC. These results can have implications for other IPC reports of short time scale variability for active galaxies and for source models based on such observations.

More than 3000 radial velocity observations across the face of the Crab Nebula are used to investigate its 3-dimensional properties. In the standard model it consists of a thick hollow shell with synchrotron emission from within. We show that the thick shell is composed of bright inner and faint outer components

The developmental course of daily functioning prior to first psychosis-onset remains poorly understood. This study explored age-related periods of change in social and role functioning. The longitudinal study included youth (aged 12–23, mean follow-up years = 1.19) at clinical high risk (CHR) for psychosis (converters [CHR-C], n = 83; nonconverters [CHR-NC], n = 275) and a healthy control group (n = 164). Mixed-model analyses were performed to determine age-related differences in social and role functioning. We limited our analyses to functioning before psychosis conversion; thus, data of CHR-C participants gathered after psychosis onset were excluded. In controls, social and role functioning improved over time. From at least age 12, functioning in CHR was poorer than in controls, and this lag persisted over time. Between ages 15 and 18, social functioning in CHR-C stagnated and diverged from that of CHR-NC, who continued to improve (p = .001). Subsequently, CHR-C lagged behind in improvement between ages 21 and 23, further distinguishing them from CHR-NC (p < .001). A similar period of stagnation was apparent for role functioning, but to a lesser extent (p = .007). The results remained consistent when we accounted for the time to conversion. Our findings suggest that CHR-C start lagging behind CHR-NC in social and role functioning in adolescence, followed by a period of further stagnation in adulthood.

There seems to be a consensus of opinion that the useful life of the commission has come to an end with the achievement of the principal aim of the historical task of the Carte du Ciel, presenting an overall picture of the Heavens as to positions of the fixed stars up to a definite limiting magnitude. The French presidents in succession with great energy, supported by the IAU, succeeded in overcoming all obstacles and in finishing the printed Astrographic Catalogue. Remaining tasks of deriving definitive plate constants, eventually deriving reliable proper motions of all stars in the programme evidently rests with individual observatories or at other commissions of the Union within their proper frame of activities.

Following a suggestion presented at the meeting of the Executive Committee in September 1969 a decision was reached to abolish the Commission 23 proper by merging it with Commission 24 (Stellar parallax and proper motion), and a working group in the latter commission would become a suitable means to continue work on data furnished by the Astrographic Catalogue.

Several of those observatories still in possession of Carte du Ciel-astrographs are going on with proper motion (p.m.) work in their zones or are preparing to do so. The application of the astrographs to the programme of attachment of stars to galaxies according to A. N. Dejč’s method is in progress.

In accordance with suggestions made by members of the Commission further consideration of the following topics is proposed:

1. (1)Improvement of the present plan for distribution of observations and computations relating to minor planets and comets, with special reference to those which depart considerably from their ephemerides.
2. (2)Designation of a central bureau to supervise any accepted plan for coordination of observations and computations. It is suggested that separate bureaus be established for Minor Planets and for Comets.
3. (3)Systematic investigations of the orbits of the recently discovered objects designated as minor planets: Reinmuth 1932 HA, and Delporte 1932 EA1( and other objects of similar interest.
4. (4)Financing of proposals (2) and (3).
5. (5)Standard equinoxes as proposed by Comrie (1950.0) and by Bower (1900.0).
6. (6)Designation of published residuals as observed residuals rather than referring to the epoch of the comparison star.
7. (7)Greater adherence to the convention “That the dates used in giving the osculation epochs of elements for comets and minor planets shall be the midnight following an integral Julian date which is exactly divisible by 40, and for ephemerides, divisible by 8 (or 4, etc.),” to facilitate intercomparison of ephemerides and elements.
8. (8)Inauguration of complete residuals of comets, similar to those of minor planets with provision for their continuation.
9. (9)Inclusion in astronomical telegrams of some information of a descriptive nature to indicate the accuracy of the measured position, in confirmation of previous action.
10. (10)Greater emphasis on accurate rather than on approximate positions, particularly in (9), or preliminary orbits.

The Report in the part dealing with the minor planets and satellites has been compiled at the Institute of Theoretical Astronomy in collaboration of S. G. Makover (minor planets) and V. A. Shor (satellites). Contributions to this report have been received from S. Arend, H. Debehogne, J. Dommanget, P. Herget, S. Herrick, G. M. Jannini, B. G. Marsden, V. V. Michkovitch, B. Milet, Z. M. Pereyra, B. Popovič, E. Rabe, E. Roemer, J. Schubart, W. Strobel, C. Torres, H. Wood. The part on comets has been prepared by E. Roemer.

The main feature of minor planet research during this triennium has been the further application of modern electronic computing machines to the practice of computing. The time has gone when the computations of orbits and ephemerides were performed with the aid of logarithmic tables or with desk calculators. Therefore it is no wonder that all computational work in the field of the motion of minor planets is nowadays concentrated in a limited number of institutions provided with powerful up-to-date computing techniques, like the following.

1. (1)Institute of Theoretical Astronomy, Leningrad has used till recently a computer BESM-2 and now has at its disposal a new more powerful computer BESM-4.
2. (2)The Observatory of Cincinnati has used till recently a powerful computer NORC. Unfortunately this machine has been nowadays dismantled, but the observatory can perform some kinds of computations with an IBM-360 computer.
3. (3)Latvian State University, Riga, has made a large amount of computations with the computer BESM-2.
4. (4)University of California, Los Angeles, makes a large amount of computations with its own computer.

Flickering is a poorly understood phenomenon associated with accretion processes, but this does not suffice to make it interesting. Why then should we bother studying this ‘noise’? Three reasons come to mind: (i) flickering is a fundamental signature of accretion, to the point of being a necessary characteristic (if it doesn’t flicker, it’s not a CV); (ii) energetically, flickering is not a small effect and can contribute up to a few tens of percent of the total luminosity of the system (hence it is often more luminous than the entire secondary star); (iii) flickering is inherently a time-dependent phenomenon and it is hoped that it can provide clues to the nature of the disc viscosity, something that time-independent theory cannot provide.

Flickering is a phenomenon associated with all known accretion powered processes. Yet despite its energetic importance and universality, our understanding of flickering remains elementary. Only recently has the flickering itself become a topic of serious investigation. This paper briefly addresses two fundamental observational questions: “Where is the flickering coming from?” and “What is the spectrum of the flickering?”.

We present 3-D LTE radiative transfer calculations [1] for H, He and Ca in accretion disks (AD) of dwarf novae in quiescence. The model disk is assumed to be in hydrostatic equilibrium vertically, and to rotate with Keplerian velocities. Calculated emission lines are fitted to phase-averaged, continuum-subtracted spectra of U Gem (Fig. 1) and T Leo (Fig. 2). Up to four parameters of the AD have been fitted: distance D, baryonic number density N, isotropic turbulence V tu and disk temperature T; the latter two are assumed to be constant throughout the disk. Geometrical parameters are from [2] and [3].

We derive the temperature and density structure of the accretion disk of the dwarf nova U Gem in quiescence from 3D radiative line and continuum transport calculations of a differentially rotating disk.

During $\text{CO}_{2}$ sequestration into a deep saline aquifer of finite vertical extent, $\text{CO}_{2}$ will tend to accumulate in structural highs such as offered by an anticline. Over times of tens to thousands of years, some of the $\text{CO}_{2}$ will dissolve into the underlying groundwater to produce a region of relatively dense, saturated water directly below the plume of  $\text{CO}_{2}$ . Continued dissolution then requires the supply of unsaturated aquifer water. In an aquifer of finite vertical extent, this may be provided by a background hydrological flow, or a laterally-spreading buoyancy-driven flow caused by the greater density of the $\text{CO}_{2}$ saturated water relative to the original aquifer water.

We investigate long time steady-state dissolution in the presence of a background hydrological flow. In steady state, the distribution of $\text{CO}_{2}$ in the groundwater upstream of the aquifer involves a balance between three competing effects: (i) the buoyancy-driven flow of $\text{CO}_{2}$ saturated water; (ii) the diffusion of $\text{CO}_{2}$ from saturated to under-saturated water; and (iii) the advection associated with the oncoming background flow. This leads to three limiting regimes. In the limit of very slow diffusion, a nearly static intrusion of dense fluid may extend a finite distance upstream, balanced by the pressure gradient associated with the oncoming background flow. In the limit of fast diffusion relative to the flow, a gradient zone may become established in which the along-aquifer diffusive flux balances the advection associated with the background flow. However, if the buoyancy-driven flow speed exceeds the background hydrological flow speed, then a third, intermediate regime may become established. In this regime, a convective recirculation develops upstream of the anticline involving the vertical diffusion of $\text{CO}_{2}$ from an upstream propagating flow of dense $\text{CO}_{2}$ saturated water into the downstream propagating flow of $\text{CO}_{2}$ unsaturated water. For each limiting case, we find analytical solutions for the distribution of $\text{CO}_{2}$ upstream of the anticline, and test our analysis with full numerical simulations. A key result is that, although there may be very different controls on the distribution and extent of $\text{CO}_{2}$ bearing water upstream of the anticline, in each case the dissolution rate is given by the product of the background volume flux and the difference in concentration between the $\text{CO}_{2}$ saturated water and the original aquifer water upstream.