234 research outputs found

    Heat transfer tests on a 0.01-scale Rockwell configuration 3 space shuttle orbiter and tank (37-OT) in the Calspan 48-inch hypersonic shock tunnel (OH12/IH21), volume 3

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    Tabulated source data are presented for wind tunnel tests conducted on scale models of the space shuttle orbiter and external tank

    Heat transfer tests on a 0.01-scale Rockwell configuration 3 space shuttle orbiter and tank (37-OT) in the Calspan 48-inch hypersonic shock tunnel (OH12/IH21), volume 1

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    Model information and data are presented from wind tunnel tests conducted on 0.01-scale models of the space shuttle orbiter and external tank. These tests were conducted in a hypersonic shock tunnel to determine heating rates on ascent and reentry configurations at various Reynolds numbers, Mach numbers, and angles of attack

    Flutter tests (IS4) of the 0.0125-scale shuttle reflection plane model 30-OTS in the Langley Research Center 26-inch transonic blowdown tunnel test no. 547

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    A series of slab wing flutter models with rigid orbiter fuselage, external tank, and SRB models of the space shuttle were tested, in a reflection plane arrangement, in the NASA Langley Research Center's 26-inch Transonic Blowdown Tunnel. Model flutter boundaries were obtained for both a wing-alone configuration and a wing-with-orbiter, tank and SRB configuration. Additional test points were taken of the wing-with-orbiter configuration, as a correlation with the wing-alone condition. A description of the wind tunnel models and test procedures utilized in the experiment are provided

    Flutter tests (OS1) of the 0.02-scale shuttle orbiter wing/elevon semi-span model 230

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    A series of simple wing/elevon flutter models of the shuttle orbiter were tested in a 26-inch transonic blowdown tunnel. Flutter points were obtained for two levels of scaled elevon actuator stiffness. A description of the wind tunnel models and the test procedures utilized in the experiment are given

    Characteristics of Child Maltreatment and Adolescent Marijuana Use: A Prospective Study

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    There has been increasing acceptance of marijuana use in the US in recent years, and rates among adolescents have risen. At the same time, marijuana use during adolescence has been linked to an array of health and social problems. Maltreated children are at risk for marijuana use, but the relationships among characteristics of maltreatment and marijuana use are unclear. In this paper we examine how the type and the extent of maltreatment are related to the level of adolescent marijuana use. Data analyses were conducted on a subsample of maltreated adolescents (n = 702) from the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN) project. Approximately half the sample had used marijuana, and maltreatment was associated with its use. Multivariate regression models showed that being male, extensive maltreatment, and peer marijuana use were associated with Heavy Use of marijuana. These findings suggest the importance of comprehensively assessing children’s maltreatment experiences and their peers’ drug use to help prevent or address possible marijuana use in these high-risk adolescents

    Analysis of US child care safety regulations.

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    BACKGROUND: With 1.9 million US children cared for in organized group child care, the safety of these children is a public health concern. In the absence of federal policy, each state has developed its own day care safety regulations. METHODS: After creating a set of 36 criteria from three sets of national guidelines, we assessed the safety regulations of 45 states. With a mailed survey of state day care regulatory personnel, we examined the processes of formulating and implementing safety policy in 47 states. RESULTS: For 24 of the 36 items, more than half the states' regulations were below the criteria or failed to mention the topic. Most notable is the inattention to playground safety, choking hazards, and firearms. CONCLUSION: The uneven quality of regulations may be a reflection of a regulatory process that is fragmented, with many different groups sharing authority and with limited involvement of injury prevention specialists

    Cellular and developmental control of O2 homeostasis by hypoxia-inducible factor 1 alpha.

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    Hypoxia is an essential developmental and physiological stimulus that plays a key role in the pathophysiology of cancer, heart attack, stroke, and other major causes of mortality. Hypoxia-inducible factor 1 (HIF-1) is the only known mammalian transcription factor expressed uniquely in response to physiologically relevant levels of hypoxia. We now report that in Hif1a-/- embryonic stem cells that did not express the O2-regulated HIF-1alpha subunit, levels of mRNAs encoding glucose transporters and glycolytic enzymes were reduced, and cellular proliferation was impaired. Vascular endothelial growth factor mRNA expression was also markedly decreased in hypoxic Hif1a-/- embryonic stem cells and cystic embryoid bodies. Complete deficiency of HIF-1alpha resulted in developmental arrest and lethality by E11 of Hif1a-/- embryos that manifested neural tube defects, cardiovascular malformations, and marked cell death within the cephalic mesenchyme. In Hif1a+/+ embryos, HIF-1alpha expression increased between E8.5 and E9.5, coincident with the onset of developmental defects and cell death in Hif1a-/- embryos. These results demonstrate that HIF-1alpha is a master regulator of cellular and developmental O2 homeostasis

    Theoretical issues of language contacts, borrowings and interference

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    The article is devoted to the theoretical problem of language contacts in modern linguistics. The problem of the relationship between language and consciousness has been comprehensively discussed: various studies of the language picture of the world are carried out by the speakers of a particular language, associative dictionaries of different languages are created, this gives rich material for studying the real perception within a particular cultur

    Genome-wide expression profiling of urinary bladder implicates desmosomal and cytoskeletal dysregulation in the bladder exstrophy-epispadias complex

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    The bladder exstrophy-epispadias complex (BEEC) represents a spectrum of urological abnormalities where part, or all, of the distal urinary tract fails to close during development, becoming exposed on the outer abdominal wall. While the etiology of BEEC remains unknown, strong evidence exists that genetic factors are implicated. To understand the pathways regulating embryonic bladder development and to identify high-probability BEEC candidate genes, we conducted a genome-wide expression profiling (GWEP) study using normal and exstrophic human urinary bladders and human and mouse embryologic bladder-precursor tissues. We identified 162 genes differentially expressed in both embryonic and postnatal human samples. Pathway analysis of these genes revealed 11 biological networks with top functions related to skeletal and muscular system development, cellular assembly and development, organ morphology, or connective tissue disorders. The two most down-regulated genes desmin (DES, fold-change, -74.7) and desmuslin (DMN, fold-change, -53.0) are involved in desmosome mediated cell-cell adhesion and cytoskeletal architecture. Intriguingly, the sixth most overexpressed gene was desmoplakin (DSP, fold-change, +48.8), the most abundant desmosomal protein. We found 30% of the candidate genes to be directly associated with desmosome structure/function or cytoskeletal assembly, pointing to desmosomal and/or cytoskeletal deregulation as an etiologic factor for BEEC. Further findings indicate that p63, PERP, SYNPO2 and the Wnt pathway may also contribute to BEEC etiology. This study provides the first expression profile of urogenital genes during bladder development and points to the high-probability candidate genes for BEEC
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