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Data Challenge 1 (DC1) is the first synthetic data set produced by the Rubin Observatory Legacy Survey of Space and Time (LSST) Dark Energy Science Collaboration (DESC). DC1 is designed to develop and validate data reduction and analysis and to study the impact of systematic effects that will affect the LSST data set. DC1 is comprised of r-band observations of 40 deg2 to 10 yr LSST depth. We present each stage of the simulation and analysis process: (a) generation, by synthesizing sources from cosmological N-body simulations in individual sensor-visit images with different observing conditions; (b) reduction using a development version of the LSST Science Pipelines; and (c) matching to the input cosmological catalogue for validation and testing. We verify that testable LSST requirements pass within the fidelity of DC1. We establish a selection procedure that produces a sufficiently clean extragalactic sample for clustering analyses and we discuss residual sample contamination, including contributions from inefficiency in star-galaxy separation and imperfect deblending. We compute the galaxy power spectrum on the simulated field and conclude that: (i) survey properties have an impact of 50 per cent of the statistical uncertainty for the scales and models used in DC1; (ii) a selection to eliminate artefacts in the catalogues is necessary to avoid biases in the measured clustering; and (iii) the presence of bright objects has a significant impact (2-6) in the estimated power spectra at small scales (> 1200), highlighting the impact of blending in studies at small angular scales in LSST.

In the title compound, [Zn(C6H3FNO2)2(H2O)4]·2H2O, the ZnII atom is octahedrally coordinated in a ZnO4N2 environment by two 3-fluoropyridine-4-carboxylate (3-fpy4-cbx) ligands and four water molecules. The [Zn(3-fpy4-cbx)2(H2O)4] molecules form a three-dimensional network through strong O—H...O and weak O—H...F hydrogen bonds between 3-fpy4-cbx and water molecules. The crystal used for data collection was a twin, with the twin law corresponding to a 180° rotation about the real-space [001] axis. The major twin fraction refined to 0.795 (1).

In the title compound, {[Zn(SO4)(C8H6N4)]·H2O}n, the ZnII atom is in a distorted octahedral environment. The ZnII atoms are bridged by both 2,2′-bipyrimidine and sulfate ligands, thus forming a three-dimensional polymeric metal–organic solid that contains uncoordinated water molecules in the interstitial space. O—H...O hydrogen bonding consolidates the crystal structure.

In the centrosymmetric title complex, [Ni(C7H3FNO3S)2(H2O)4], the NiII atom exhibits a slightly distorted trans-NiN2O4 octahedral coordination. The nitrogen donors are provided by two 5-fluorosaccharinate ligands and the oxygen donors are provided by four water molecules. The crystal structure features O—H...O and bifurcated O—H...(F,O) hydrogen bonds, the latter involving the F atom of the 5-fluorosaccharinate ligand.

In general terms the changes at SBA-1 appear to reflect a broadening of the resource base, with fish and shellfish making up a greater share of the protein captured in the later period. This is in general agreement with the patterns predicted by regional theories dealing with environmental change and population growth in the Santa Barbara Channel region (Glassow 1980a: 14). Archaeological data (Glassow, Wilcoxon, and Erlandson n.d.) suggest that populations in the channel region were increasing during the periods in question. Such an increase in the number of people utilizing the region's resources would be likely to produce an intensification in the use of the marine environment as a result of the limitations on the terrestrial resources in the narrow coastal zone. The data from SBA-1 appear to show the effects of such intensification.

Since the 1970s, smoking has declined somewhat among adolescent males, but not among adolescent females. Many adolescents continue to smoke despite exposure to prevention programs and knowledge of its adverse [...], Part of the Hutchinson Smoking Prevention Project, this study provides information on reasons reported by adolescents for their smoking behavior. A total of 1,615 10th grade students in 20 rural and suburban school districts in Washington state were asked why they currently smoke and why they first smoked. For beginning smoking, curiosity, social norms, and social pressure were the most frequently given reasons for smoking. For current smoking, pleasure and addiction were mentioned most often. A number of gender differences occurred with 10th grade students beginning and current smoking. More females than males reported social norms and social pressure as reasons for beginning to smoke, whereas for currently smoking, pleasure was given as a reason more frequently by females than males. When developing interventions, smoking prevention programs need to consider students' current and past smoking behavior, and the reasons they give for smoking. (J Sch Health. 1992;62(5):185-190)