Design verification test matrix development for the STME thrust chamber assembly

This report presents the results of the test matrix development for design verification at the component level for the National Launch System (NLS) space transportation main engine (STME) thrust chamber assembly (TCA) components including the following: injector, combustion chamber, and nozzle. A systematic approach was used in the development of the minimum recommended TCA matrix resulting in a minimum number of hardware units and a minimum number of hot fire tests

Paretian Intergenerational Discounting

This paper argues that discounting costs and benefits of projects for the opportunity costs of capital Pareto dominates decision criteria that do not discount. It considers and rejects several objections to the Pareto dominance argument, including the problem of making compensating transfers for the costs and benefits of projects and whether taking opportunity costs into account is different than discounting. It also argues that discounting future costs and benefits of projects does not undervalue future generations

A Retrospective Time Series Analysis Of Oyster, Crassostrea Virginica, Recruitment (1946-1993)

Temporal patterns of eastern oyster, Crassostrea virginica (Gmelin 1791), spatfall in the Virginia tributary rivers to the Chesapeake Bay showed a decline in all rivers from 1946 through the early 1970s, with a subsequent leveling off. The decline was most severe in the James and less so moving north to the York and Rappahannock Rivers; it was least severe in the Potomac River. Yearling patterns generally mirrored the spat. Cluster analyses grouped the bars naturally by up- and downriver spatfall patterns. They also clustered this way when between-river comparisons were made. Spatfall showed a significant cross-correlation with yearlings a year later in all Virginia rivers, which suggests that the \u27\u27yearling\u27\u27 designation was accurate and that spat counts may be used to predict yearling abundance. The relation of spat to later seed was significant for the James River at 2 and 3 y, but none was found between spat and market oyster. James River seed demonstrated a slightly significant relation to market oyster 4 y later. Regression analyses between spat counts and spring and summer water temperatures and river discharge produced little explanation of spat variation. There was, however, a significant relation between spat count and the Palmer Drought Index. The drought index is a combination of rainfall, soil type, and evapotranspiration. When the period of the greatest change in the drought index was correlated with spatfall, there was found to be a significant 2- to 4-y lag. We suggest that this reflects a response by the ecosystem to changing environmental conditions

Bullying Victimization and Perpetration: Some Answers and More Questions

The U.S. government has defined bullying victimization as “any unwanted aggressive behavior(s) by another youth or group of youths who are not siblings or current dating partners that involves an observed or perceived power imbalance and is repeated multiple times or is highly likely to be repeated”.1 Conceptualizations of bullying and the use of the term vary by audience and context. For instance, for some, bullying behaviors might include acts of aggression or violence, whereas for others bullying might center on name-calling, exclusionary social practices or even spreading rumors and vicious lies.

Community Violence Exposure and Sexual Behaviors in a Nationally Representative Sample of Young Adults: The Effects of Race/Ethnicity and Gender

This study examined whether exposure to community violence was related to sexual risk behaviors in a nationally representative sample of young adults and if there were gender or racial/ethnic differences in these relationships. The analytic sample for this study was drawn from the National Longitudinal Study of Adolescent Health and was composed of 7,726 unmarried, heterosexual African American, Caucasian, and Hispanic/Latino young adults aged 18 to 27 years old. Approximately 12% of participants reported some community violence exposures, with men and African Americans reporting the highest rates of such exposures. Regression analyses controlling for age, gender, parental education, and family structure indicated that exposures to community violence were associated with earlier sexual debut history, a higher number of sexual partners within the previous 12 months, and a higher number of total sexual partners. Additionally, violence exposures had stronger effects for males and weaker effects for African Americans. Primary and secondary sexual risk prevention initiatives would need to consider how patterns of sexual risk behaviors may be related to exposure to community violence and how such relationships may differ based on gender and race/ethnicity. Future research should also seek to illuminate pathways connecting these 2 major public health concerns

Interim outcomes of mechanical thrombectomy for deep vein thrombosis from the all-comer CLOUT registry

OBJECTIVES: The multicenter, prospective, single arm CLOUT registry assesses the safety and effectiveness of the ClotTriever System (Inari Medical, Irvine, CA) for the treatment of acute and nonacute lower extremity deep vein thrombosis (DVT) in all-comer patients. Reported here are the outcomes of the first 250 patients. METHODS: All-comer patients with lower extremity DVT were enrolled, including those with bilateral DVT, those with previously failed DVT treatment, and regardless of symptom duration. The primary effectiveness end point is complete or near-complete (≥75%) thrombus removal determined by independent core laboratory-adjudicated Marder scores. Safety outcomes include serious adverse events through 30 days and clinical outcomes include post-thrombotic syndrome severity, symptoms, pain, and quality of life through 6 months. RESULTS: The median age was 62 years and 40% of patients had contraindications to thrombolytics. A range of thrombus chronicity (33% acute, 35% subacute, 32% chronic) was observed. No patients received thrombolytics and 99.6% were treated in a single session. The median thrombectomy time was 28 minutes. The primary effectiveness end point was achieved in 86% of limbs. Through 30 days, one device-related serious adverse event occurred. At 6 months, 24% of patients had post-thrombotic syndrome. Significant and sustained improvements were observed in all clinical outcomes, including the Revised Venous Clinical Severity Score, the numeric pain rating scale, and the EuroQol Group 5-Dimension Self-Report Questionnaire. CONCLUSIONS: The 6-month outcomes from the all-comer CLOUT registry with a range of thrombus chronicities demonstrate favorable effectiveness, safety, and sustained clinical improvements