Suicidal ideation and its recurrence in boys and men from early adolescence to early adulthood: An event history analysis.

Occurrence and recurrences of suicidal ideation (SI) were modeled among boys/men assessed annually from ages 12 to 29 years. Multiple-spell discrete-time event-history analyses permitted (a) determination of whether risk for SI escalates with prior experiences of SI (spell effects), while (b) accounting for changes in risk with time (period effects) and (c) controlling for vulnerability factors. Self-reported SI (presence/absence in past week), depressive symptoms, alcohol/substance use, antisocial behavior, and official arrest records were collected annually from 205 boys recruited on the basis of community risk for delinquency. Parents' self-reported psychopathology and SES were collected in childhood. Period effects supported decreasing risk for SI over time. Spell and time-varying 1-year lagged substance use and depressive symptoms independently predicted increased risk for SI. Models involving SI with intent were explored. Consistent with interpersonal psychological theory, risk for young men's SI increases with past experience of SI, even with key propensities controlled. However, risk also decays over time. Targeting conditions that confer risk for SI is essential. Preventing and delaying SI occurrence and recurrence may represent independent mechanisms by which prevention efforts operate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

DETERMINATION OF IRON OXIDE AND TITANIA IN CLAY REFRACTORIES1

Customary method of determining iron oxide and titania from ignited R₂O₂ precipitate requires considerable time. Direct titration of fusions with sodium carbonate is impossible because of gelatinous silica. Direct titration of fusions with potassium bisulphate is accurate with clays low in silica and unfired clays. By treating with hydrofluoric and sulphuric acid, and dissolving with dilute hydrochloric and precipitating the R₂O₂ by ammonium hydroxide and then fusing with potassium bisulphate the iron and titanium oxide can with accuracy be titrated. A detail method of procedure is given.     

Space shuttle meteoroid and orbital debris impact damage

Post-flight surveys of meteoroid and orbital debris (M&OD) impacts on the Space Shuttle Orbiter are conducted to identify damage caused by hypervelocity impacts from M&OD and to identify the source (i.e., whether meteoroid or orbital debris) of the projectiles responsible [1,2] This report provides data on Orbiter M&OD impacts for a five-year period and describes in detail the 39 most significant impacts. For the period 6/92 through 12/99 there were 49 Shuttle Transportation System (STS) missions (STS-50 through STS-103) of which 38 had post-flight inspections to identify M&OD impacts. Approximately 10% of the vehicle is surveyed in the M/OD inspections. The data for the 39 most significant impacts based on size found during the inspections are summarized in Table 1. This work contains estimates of impactor size which were determined using appropriate impact damage penetration equations that were derived by hypervelocity impact (HVI) test and analysis on relevant Orbiter materials. Although predictions for numbers of impacts are produced for each STS mission, we do not compare those predictions to the actual damage reported here as further efforts must be made to analyze the as-flown attitude timeline and adjust the predicted damage accordingly.