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41.
Recent studies of children''s tool innovation have revealed that there is variation in children''s success in middle-childhood. In two individual differences studies, we sought to identify personal characteristics that might predict success on an innovation task. In Study 1, we found that although measures of divergent thinking were related to each other they did not predict innovation success. In Study 2, we measured executive functioning including: inhibition, working memory, attentional flexibility and ill-structured problem-solving. None of these measures predicted innovation, but, innovation was predicted by children''s performance on a receptive vocabulary scale that may function as a proxy for general intelligence. We did not find evidence that children''s innovation was predicted by specific personal characteristics.  相似文献   
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Allogromiid foraminifera and gromiids constitute an important but poorly known component of the meiobenthos in high-latitude marine settings. Here, we present a first report on the diversity of these protists, together with an account of co-occurring invertebrate taxa, in a sample of sea floor sediment from a water depth of 923 m under the Ross Ice Shelf. Light microscopy of sieved sediment yielded 14 allogromiid foraminifera and three Gromia spp. morphotypes. We also obtained 36 partial small subunit rDNA sequences of allogromiids, including 19 sequences of individual isolates and 17 sequences from environmental DNA samples. Phylogenetic analyses of the obtained sequences identified 18 phylotypes, of which seven were closely related to previously sequenced allogromiids, while 11 represented new lineages. Our results demonstrate that a rich meiofaunal assemblage is present under the Ross Ice Shelf, 12 km from the open ocean. Molecular phylogenetic analyses of these allogromiid foraminifera point to the endemic character of the Ross Ice Shelf assemblage; however, more extensive sampling of the molecular diversity of this group of foraminifera in the Antarctic deep sea is necessary to confirm this conclusion.  相似文献   
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Pulmonary vascular compliance and viscoelasticity   总被引:1,自引:0,他引:1  
When dog lung lobes were perfused at constant arterial inflow rate, occlusion of the venous outflow (VO) produced a rapid jump in venous pressure (Pv) followed by a slower rise in both arterial pressure (Pa) and Pv. During the slow rise Pa(t) and Pv(t) tended to converge and become concave upward as the volume of blood in the lungs increased. We compared the dynamic vascular volume vs. pressure curves obtained after VO with the static volume vs. pressure curves obtained by dye dilution. The slope of the static curve (the static compliance, Cst) was always larger than the slope of the dynamic curve (the dynamic compliance, Cdyn). In addition, the Cdyn decreased with increasing blood flow rate. When venous occlusion (VO) was followed after a short time interval by arterial occlusion (AO) such that the lobe was isovolumic, both Pa and Pv fell with time to a level that was below either pressure at the instant of AO. In an attempt to explain these observations a compartmental model was constructed in which the hemodynamic resistance and vascular compliance were volume dependent and the vessel walls were viscoelastic. These features of the model could account for the convergence and upward concavity of the Pa and Pv curves after VO and the pressure relaxation in the isovolumic state after AO, respectively. According to the model analysis, the difference between Cst and Cdyn and the flow dependence of Cdyn are due to wall viscosity and volume dependence of compliance, respectively. Model analysis also suggested ways of evaluating changes in the viscoelasticity of the lobar vascular bed. Hypoxic vasoconstriction that increased total vascular resistance also decreased Cst and Cdyn and appeared to increase the vessel wall viscosity.  相似文献   
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Calcareous nannofossil diversity, and rates of speciation and extinction are calculated for five million year intervals from their first appearance in the Late Triassic through to the Present Day. Important evolutionary events are as follows: first appearance in the Late Triassic, Triassic‐Jurassic boundary extinctions, Tithonian radiation (and the first occurrence of nannofossil carbonates), Late Cretaceous diversity maximum, Cretaceous‐Tertiary boundary extinctions, Palaeocene radiation, mid Eocene to Oligocene diversity decline, and early Miocene diversity rise. These events are related to possible causal factors of which climate appears to be the most fundamental. Other factors may include biogeographical isolation, sea level change, and the configuration of Mesozoic oceans.  相似文献   
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Molecular mechanisms that provide for cGMP activation of cGMP-dependent protein kinase (PKG) are unknown. PKGs are dimeric; each monomer contains a regulatory (R) and catalytic (C) domain. In this study, isolated recombinant R domains of PKGIalpha-(Delta349-670) and PKGIbeta-(Delta364-685) containing the dimerization and autoinhibitory subdomains and two allosteric cGMP-binding sites were expressed in Sf9 cells. Both R domains were dimers with elongated conformations (Stokes radii of 44 and 51 A, respectively, and frictional coefficients of 1.6 and 1.8, respectively). Exchange dissociation kinetics and K(D) values for cGMP were similar for each holoenzyme and its isolated R domain, indicating that under these conditions the C domain does not appreciably alter cGMP-binding functions of the R domain. As determined by gel filtration chromatography, cGMP binding caused elongation of the PKGIalpha-isolated R domain and contraction of the PKGIbeta-isolated R domain. Cyclic GMP-bound forms of the isoforms have similar physical dimensions that may reflect a common conformation of active isoforms. Elongation of the PKGIbeta holoenzyme associated with cGMP binding and PKG activation cannot be explained solely by conformational change in its R domain, but elongation of the PKGIalpha R domain may partially account for the elongation of wild type PKGIalpha associated with cGMP binding. The cGMP-induced conformational changes in the respective R domains are likely to be critical for kinase activation.  相似文献   
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The essence of learning is change; learning is the process by which learners customize new information to make it personally meaningful and relevant. Training is the process of helping students make those changes. Research indicates that adults learn differently than children or adolescents and that adults consistently use the following six learning strategies: prior experiences; conversations; metacognition; reflection; authentic experiences; and images, pictures, or other types of visuals. Each of these learning strategies can be combined with the other strategies and often build upon each other. A recent study on how health care professionals learn indicated that the learning strategy they used most often was reflection, which supports learning before, during, and after training. Numerous examples are provided in this article describing how to integrate each of the six adult learning strategies into laboratory animal science training. While lectures and other types of direct instruction are appropriate, they are inadequate and ineffective unless they are integrated with and support adult learning strategies. Both the US Department of Agriculture regulations and the Public Health Service Policy mandate that research institutions must ensure that all personnel involved in animal care, treatment, or use are qualified to perform their duties. Applying adult learning strategies to training for the laboratory animal science community will enhance learning and improve both the science and the humane care of the animals, which is a goal our community must continuously strive to achieve.  相似文献   
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Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an autosomal dominant disorder characterized by smooth-muscle tumors of the skin and uterus and/or renal cancer. Although the identification of germline mutations in the fumarate hydratase (FH) gene in European families supports it as the susceptibility gene for HLRCC, its role in families in North America has not been studied. We screened for germline mutations in FH in 35 families with cutaneous leiomyomas. Sequence analysis revealed mutations in FH in 31 families (89%). Twenty different mutations in FH were identified, of which 18 were novel. Of these 20 mutations, 2 were insertions, 5 were small deletions that caused frameshifts leading to premature truncation of the protein, and 13 were missense mutations. Eleven unrelated families shared a common mutation: R190H. Eighty-one individuals (47 women and 34 men) had cutaneous leiomyomas. Ninety-eight percent (46/47) of women with cutaneous leiomyomas also had uterine leiomyomas. Eighty-nine percent (41/46) of women with cutaneous and uterine leiomyomas had a total hysterectomy, 44% at age < or =30 years. We identified 13 individuals in 5 families with unilateral and solitary renal tumors. Seven individuals from four families had papillary type II renal cell carcinoma, and another individual from one of these families had collecting duct carcinoma of the kidney. The present study shows that mutations in FH are associated with HLRCC in North America. HLRCC is associated with clinically significant uterine fibroids and aggressive renal tumors. The present study also expands the histologic spectrum of renal tumors and FH mutations associated with HLRCC.  相似文献   
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