1,456 research outputs found

    Longitudinal aerodynamic characteristics of a subsonic, energy-efficient transport configuration in the National Transonic Facility

    Get PDF
    The Reynolds number, aeroelasticity, boundary layer transition, and nonadiabatic wall temperature effects, and data repeatability was determined in the National Transonic Facility (NTF) for a subsonic, energy efficient transport model. The model was tested over a Mach number range of 0.50 to 0.86 and a Reynolds number range of 1.9 million to approximately 23.0 million (based on mean geometric chord). The majority of the data was taken using cryogenic nitrogen (data at 1.9 million Reynolds number was taken in air). Force and moment, wing pressure, and wing thermocouple data are presented. The data indicate that increasing Reynolds number resulted in greater effective camber of the supercritical wing and horizontal tail, resulting in greater lift and pitching moment coefficients at nearly all angles of attack for M = 0.82. As Reynolds number was increased, untrimmed L/D increased, the angle of attack for maximum L/D decreased, drag creep was reduced significantly, and drag divergence Mach number increased slightly. Data repeatability for both modes of operation of the NTF (air and cryogenic nitrogen) was generally very good, and nonadiabatic wall effects were estimated to be small. Transition-free and transition-fixed configurations had significantly different force and moment data at M = 0.82 for low Reynolds number, and very small differences were noted at high Reynolds numbers

    The zinc finger transcription factor PLAGL2 enhances stem cell fate and activates expression of ASCL2 in intestinal epithelial cells

    Get PDF
    O encaminhamento de textos originais para submissão seguem algumas orientações básicas, levando em conta, inicialmente, que devem ser inéditos e que serão submetidos à aprovação de avaliadores especialistas nos temas tratados. Para acessar as informações acerca dos objetivos, da política editorial e das diretrizes e normas de publicação da Revista Trabalho & Educação, clique nos links SOBRE e/ou NORMAS, localizados no topo da página eletrônica da Revista. Agradecemos muitíssimo o interesse em publicar na Revista

    Direct Reaction – One Step Route to Synthesize Lanthanoid-iodide Formamidinates**

    Get PDF
    This paper describes a novel and simple method – direct reaction of lanthanoid metals with equimolar amounts of iodine and a formamidine under ultrasonication as an effective, metal-based route to lanthanoid(III) diiodide formamidinates, namely I. N,N′-Bis(2,6-diisopropylphenyl)formamidinatodiiodidolanthanoid(III) complexes [Ln(DippForm)I2(thf)3] (Ln=La, 1, Ce, 2, Tb, 3, Ho, 4, Er, 5, Tm, 6); II. N,N′-Bis(2,6-diethylphenyl)formamidinatodiiodidolanthanoid(III) complexes [Ln(EtForm)I2(thf)3] (Ln=Ce, 7, Nd, 8, Gd, 9, Tb, 10, Dy, 11, Ho, 12, Er, 13, Lu, 14). III. N,N′-bis(2,6-dimethylphenyl)formamidinatodiiodidolanthanoid(III) complexes [Ln(XylForm)I2(thf)3] (Ln=Ce, 15, Nd, 16, Gd, 17, Tm, 18, Lu 19); IV. ,N′-bis(phenyl)formamidinatodiiodidolanthanoid complexes [Ln(PhForm)I2(thf)3] (Ln=Nd, 20, Gd, 21, Er, 22). Compound [Ce(XylForm)2I(thf)2] (23) was also synthesized by the same method except the ratio of I2 to XylFormH was 1 : 4. Divalent N,N′-bis(2,6-diisopropylphenyl)formamidinato-iodido-lanthanoid(II) complexes [Eu(DippForm)I(thf)4] ⋅ thf (24), [Yb(DippForm)I(thf)3] ⋅ 2DippFormH (25), [Sm(DippForm)I(thf)4] ⋅ thf (26) have also been synthesized by direct reactions of the free metals, iodine and DippFormH. Interestingly, [Sm(DippForm)I2(thf)3] (27) was obtained by the oxidation of [Sm(DippForm)I(thf)4] ⋅ thf (26) on exposure to air. N,N′-Bis(2,6-dimethylphenyl)formamidinatoiodidosamarium(II) [Sm(XylForm)I(thf)3]n (28) was also prepared by direct reaction of Sm, iodine and XylFormH (mole ratio of I2: XylFormH=1 : 2). All products have been identified by X-ray crystallography and all the trivalent complexes [Ln(Form)nI3-n] (n=1 or 2) are stable to rearrangement

    Movement of Xylosandrus germanus (Coleoptera: Curculionidae) in Ornamental Nurseries and Surrounding Habitats

    Get PDF
    Some exotic ambrosia beetles are damaging pests in ornamental nurseries. Xylosandrus germanus (Blandford) is the most problematic ambrosia beetle in Ohio nurseries. Movement of X. germanus in nurseries has not been characterized, and knowledge is lacking on whether infestations originate from within nurseries or surrounding habitats. Flight activity of X. germanus was monitored in nurseries and adjacent wooded areas to determine the source of beetles infesting nurseries, and characterize their movement within nurseries. Ethanol-baited bottle traps were positioned within wooded areas adjacent to commercial nurseries and within nurseries at various distances from the nursery woodlot interface. Flight activity of overwintered X. germanus occurred in wooded areas adjacent to nurseries before occurrence within nurseries. There was a direct relationship between degree-days and the distance from woodlots when X. germanus were first found in traps in spring, with earlier captures closest to wooded areas and latest ones furthest away into the nursery. X. germanus appeared to move into nurseries from adjacent wooded areas, with numbers trapped within nurseries decreasing with distance away from wooded areas. Trees in the interior of nurseries would appear to be subjected to less attack pressure than trees near the nursery border. Intercepting beetles as they move into nurseries might be an effective strategy to reduce attack pressure on valuable trees

    In the beginning: Role of autonomy support on the motivation, mental health and intentions of participants entering an exercise referral scheme

    Get PDF
    Self-determination theory (Deci & Ryan, 2000, Intrinsic motivation and self-determination in human behaviour. New York: Plenum Publishing) highlights the impact autonomy supportive environments can have on exercise motivation and positive health outcomes. Yet little is known about whether differential effects occur as a function of which significant other is providing this support. Further, no research has examined the relationship between motivation and the social environment with participants’ mental health and intentions to be physically active before entering an exercise intervention. Study participants were 347 British adults who were about to start an exercise referral scheme. Regression analyses revealed that the effects of autonomy support on mental health and physical activity intentions differed as a function of who provided the support (offspring, partner or physician), with the offspring having the weakest effects. A structural model was supported, indicating that autonomy support and more autonomous regulations led to more positive mental health outcomes and stronger intentions to be physically active. Knowledge of the social environmental and personal motivation of those about to commence an exercise programme can provide important insights for professionals supporting such efforts

    An empirical assessment and comparison of species-based and habitat-based surrogates: a case study of forest vertebrates and large old trees

    Get PDF
    A holy grail of conservation is to find simple but reliable measures of environmental change to guide management. For example, particular species or particular habitat attributes are often used as proxies for the abundance or diversity of a subset of other taxa. However, the efficacy of such kinds of species-based surrogates and habitat-based surrogates is rarely assessed, nor are different kinds of surrogates compared in terms of their relative effectiveness. We use 30-year datasets on arboreal marsupials and vegetation structure to quantify the effectiveness of: (1) the abundance of a particular species of arboreal marsupial as a species-based surrogate for other arboreal marsupial taxa, (2) hollow-bearing tree abundance as a habitat-based surrogate for arboreal marsupial abundance, and (3) a combination of species- and habitat-based surrogates. We also quantify the robustness of species-based and habitat-based surrogates over time. We then use the same approach to model overall species richness of arboreal marsupials. We show that a species-based surrogate can appear to be a valid surrogate until a habitat-based surrogate is co-examined, after which the effectiveness of the former is lost. The addition of a species-based surrogate to a habitat-based surrogate made little difference in explaining arboreal marsupial abundance, but altered the co-occurrence relationship between species. Hence, there was limited value in simultaneously using a combination of kinds of surrogates. The habitat-based surrogate also generally performed significantly better and was easier and less costly to gather than the species-based surrogate. We found that over 30 years of study, the relationships which underpinned the habitat-based surrogate generally remained positive but variable over time. Our work highlights why it is important to compare the effectiveness of different broad classes of surrogates and identify situations when either species- or habitat-based surrogates are likely to be superior.This study has been funded by the Australian Research Council, Parks Victoria, the Department of Sustainability and Environment (and its predecessor departments), Melbourne Water, the Earthwatch Institute, the Thomas Foundation and Lindenmayer’s personal funds

    Dynamic clonal progression in xenografts of acute lymphoblastic leukemia with intrachromosomal amplification of chromosome 21

    Get PDF
    Intrachromosomal amplification of chromosome 21 is a heterogeneous chromosomal rearrangement occurring in 2% of childhood precursor B-cell acute lymphoblastic leukemia. There are no cell lines with iAMP21 and these abnormalities are too complex to faithfully engineer in animal models. As a resource for future functional and pre-clinical studies, we have created xenografts from intrachromosomal amplification of chromosome 21 leukemia patient blasts and characterised them by in-vivo and ex-vivo luminescent imaging, FLOW immunophenotyping, and histological and ultrastructural analysis of bone marrow and the central nervous system. Investigation of up to three generations of xenografts revealed phenotypic evolution, branching genomic architecture and, compared with other B-cell acute lymphoblastic leukemia genetic subtypes, greater clonal diversity of leukemia initiating cells. In support of intrachromosomal amplification of chromosome 21 as a primary genetic abnormality, it was always retained through generations of xenografts, although we also observed the first example of structural evolution of this rearrangement. Clonal segregation in xenografts revealed convergent evolution of different secondary genomic abnormalities implicating several known tumour suppressor genes and a region, containing the B-cell adaptor, PIK3AP1, and nuclear receptor co-repressor, LCOR, in the progression of B-ALL. Tracking of mutations in patients and derived xenografts provided evidence for co-operation between abnormalities activating the RAS pathway in B-ALL and for their aggressive clonal expansion in the xeno-environment. Bi-allelic loss of the CDKN2A/B locus was recurrently maintained or emergent in xenografts and also strongly selected as RNA sequencing demonstrated a complete absence of reads for genes associated with the deletions

    Biology, Ecology, and Management of Nonnative Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae) in Ornamental Plant Nurseries

    Get PDF
    Xylosandrus germanus (Blandford) and Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae: Scolytinae) are two of the most damaging nonnative ambrosia beetle pests in ornamental plant nurseries. Adult females tunnel into the stems and branches of host plants to create galleries with brood chambers. Hosts are infected with symbiotic Ambrosiella spp. fungi that serve as food for the larvae and adults. Plants can also become infected with secondary opportunistic pathogens, including Fusarium spp. Both X. germanus and X. crassiusculus have broad host ranges, and infestations can result in “toothpicks” of extruded chewed wood and sap flow associated with gallery entrances, canopy dieback, stem and trunk cankers, and plant death. Beetles efficiently locate and preferentially attack living, weakened plants, especially those physiologically stressed by flooding, inadequate drainage, frost injury, or winter injury and low temperature. Maintaining plant health is the foundation of a management plan. Vulnerable hosts can be partially protected with preventive pyrethroid applications in the spring before peak flight and attack, which are monitored using ethanol-based trapping tactics

    The Diversity of High- and Intermediate-Velocity Clouds: Complex C versus IV Arch

    Get PDF
    We present Far Ultraviolet Spectroscopic Explorer (FUSE) and Space Telescope Imaging Spectrograph (STIS) observations of interstellar ultraviolet absorption lines in the Galactic high-velocity cloud Complex C and the Intermediate Velocity Arch (IV Arch) in direction of the quasar PG 1259+593 (l=120,b=+58 deg). Absorption lines from CII, NI, NII, OI, AlII, SiII, PII, SII, ArI, FeII, and FeIII are used to study the atomic abundances in these two halo clouds at V_LSR=-130 km/s (Complex C) and V_LSR=-55 km/s (IV Arch). The OI/HI ratio provides the best measure of the overall metallicity in the diffuse interstellar medium, because ionization effects do not alter the ratio, and oxygen is at most only lightly depleted from the gas into dust grains. For Complex C, we find an oxygen abundance of 0.093 (+0.125, -0.047) solar, consistent with the idea that Complex C represents the infall of low metallicity gas onto the Milky Way. In contrast, the oxygen abundance in the IV Arch is 0.98 (+1.21,-0.46) solar, which indicates a Galactic origin. We report the detection of an intermediate- velocity absorption component at +60 km/s that is not seen in HI 21cm emission. The clouds along the PG 1259+593 sight line have a variety of properties, proving that multiple processes are responsible for the creation and circulation of intermediate- and high-velocity gas in the Milky Way halo.Comment: 12 pages, 3 tables, 3 figures; accepted for publication in Ap
    • …
    corecore