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31.
An updated analysis of the ocean surface wind direction signal in passive microwave brightness temperatures 总被引:2,自引:0,他引:2
We analyze the wind direction signal for vertically (v) and horizontally (h) polarized microwave radiation at 37 GHz, 19 GHz, and 11 GHz; and an Earth incidence angle of 53/spl deg/. We use brightness temperatures from SSM/I and TMI and wind vectors from buoys and the QUIKSCAT scatterometer. The wind vectors are space and time collocated with the radiometer measurements. Water vapor, cloud water and sea surface temperature are obtained from independent measurements and are uncorrelated with the wind direction. We find a wind direction signal that is noticeably smaller at low and moderate wind speeds than a previous analysis had indicated. We attribute the discrepancy to errors in the atmospheric parameters that were present in the data set of the earlier study. We show that the polarization combination 2v-h is almost insensitive to atmospheric changes and agrees with the earlier results. The strength of our new signals agrees well with JPL aircraft radiometer measurements. It is significantly smaller than the prediction of the two-scale sea surface emission model for low and intermediate wind speeds. 相似文献
32.
Kersten Alan W.; Meissner Christian A.; Lechuga Julia; Schwartz Bennett L.; Albrechtsen Justin S.; Iglesias Adam 《Canadian Metallurgical Quarterly》2010,139(4):638
Three experiments provide evidence that the conceptualization of moving objects and events is influenced by one's native language, consistent with linguistic relativity theory. Monolingual English speakers and bilingual Spanish/English speakers tested in an English-speaking context performed better than monolingual Spanish speakers and bilingual Spanish/English speakers tested in a Spanish-speaking context at sorting novel, animated objects and events into categories on the basis of manner of motion, an attribute that is prominently marked in English but not in Spanish. In contrast, English and Spanish speakers performed similarly at classifying on the basis of path, an attribute that is prominently marked in both languages. Similar results were obtained regardless of whether categories were labeled by novel words or numbered, suggesting that an English-speaking tendency to focus on manner of motion is a general phenomenon and not limited to word learning. Effects of age of acquisition of English were also observed on the performance of bilinguals, with early bilinguals performing similarly in the 2 language contexts and later bilinguals showing greater contextual variation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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By using a simplified model of small open liquid-like clusters with surface effects, in the gas phase, it is shown how the statistical thermodynamics of small systems can be extended to include metastable supersaturated gaseous states not too far from the gas-liquid equilibrium transition point. To accomplish this, one has to distinguish between mathematical divergence and physical convergence of the open-system partition function. 相似文献
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Tumor cells that express a fusion gene comprised of Escherichia coli cytosine deaminase (CD) and herpes simplex virus type 1 thymidine kinase (TK) sequences exhibit activation of and subsequent killing by the normally innocuous prodrugs 5-fluorocytosine and ganciclovir (Rogulski et al., Hum. Gene Ther., 8: 73-85, 1997). To target localized expression of this therapeutic gene, we have constructed a recombinant adenovirus containing the CD-TK fusion gene under the control of a human inducible heat shock protein 70 promotional sequence. Strong expression of the fusion gene product was induced by heating at 41 degrees C for 1 h. Expression levels obtained were dependent on the multiplicity of infection used and the incubation time after heat shock. Heat-induced expression of the CD-TK protein significantly reduced the survival of PC-3 cells in the presence of both 5-fluorocytosine and ganciclovir. These studies represent a novel form of gene therapy for the transduction and regulation of a double suicide gene in tumor cells and may provide a unique application for hyperthermia in cancer therapy. 相似文献
37.
EL Palacios-Prü L Miranda-Contreras RV Mendoza-Brice?o JR Lozano-Hernández 《Canadian Metallurgical Quarterly》1998,18(2):267-284
1. Information obtained during the last decade has demonstrated that hypothalamic neurons release a wide variety of neuroactive substances, such as neurotransmitters, mostly monoamines and amino acids, and neuromodulators such as the peptides vasopressin (AVP) and oxytocin (OXT) and hypophysial releasing hormones. 2. Synapse formation between hypothalamic neurons was followed at different times within a given nucleus and among different nuclei during development of the mouse hypothalamus. 3. The amounts of various neurotransmitters and hormones were determined at various stages of development. 4. A correlation is presented of the biochemical and ultrastructural features and their functional implications during maturation. 相似文献
38.
Egbert Meissner Jerzy Myszkowski Jan Szymanowski Rakan Barhoum 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1993,57(1):49-55
Nonionic surfactants having polydisperse polyoxyethylene chains and highly fluorinated hydrophobes were synthesized via a complex reaction route and their adsorption at water/air interfaces studied. They exhibit high surface activity and decrease both effectively and efficiently the surface tension of their aqueous solutions. The effect of the length of the polyoxyethylene chain upon surfactant surface activity is relatively low. Lower values of surface tension, below 30 mN m?1, are obtained for surfactants having a low degree of ethoxylation. Surfactants having two terminal highly fluorinated hydrophobes are less surface active than analogues with one terminal hydrophobe. 相似文献
39.
RV West 《Canadian Metallurgical Quarterly》1998,26(2):63-71
The value of routine follow-up programs for patients with early stage breast cancer remains an area of controversy. In recent years, the cost-effectiveness of routine investigations has been questioned, and 2 prospective randomized clinical trials have shown no survival advantage to more intensive diagnostic follow-up approaches. Under the auspices of the Ottawa Regional Cancer Centre, a national survey of the practice patterns of Canadian surgical, radiation and medical oncologists was undertaken to measure current Canadian standards of care and to determine average costs of 5-year follow-up for patients completing primary treatment for stage I and II breast cancer. Standardized questionnaires were sent out to 130 surgeons, 59 radiation oncologists and 89 medical oncologists. The overall response rate was 44%. Based on the frequency of follow-up visits and investigations recommended by respondents, an average cost per patient for a 5-year follow-up plan was derived for each subspecialist group: $791, $911 and $904 for surgeons, radiation oncologists and medical oncologists respectively. Use of a less interventionist follow-up program was estimated to result in a cost saving of $300 per patient over 5 years. The results indicate that, for the most part, Canadian oncologists have been influenced by the available literature concerning follow-up practices and are ordering fewer routine tests. Further cost savings to the Canadian health care system could be achieved with the adoption of even less interventionist follow-up programs. 相似文献
40.
D Perrotti S Bonatti R Trotta R Martinez T Skorski P Salomoni E Grassilli RV Lozzo DR Cooper B Calabretta 《Canadian Metallurgical Quarterly》1998,17(15):4442-4455
The leukemogenic potential of BCR/ABL oncoproteins depends on their tyrosine kinase activity and involves the activation of several downstream effectors, some of which are essential for cell transformation. Using electrophoretic mobility shift assays and Southwestern blot analyses with a double-stranded oligonucleotide containing a zinc finger consensus sequence, we identified a 68 kDa DNA-binding protein specifically induced by BCR/ABL. The peptide sequence of the affinity-purified protein was identical to that of the RNA-binding protein FUS (also called TLS). Binding activity of FUS required a functional BCR/ABL tyrosine kinase necessary to induce PKCbetaII-dependent FUS phosphorylation. Moreover, suppression of PKCbetaII activity in BCR/ABL-expressing cells by treatment with the PKCbetaII inhibitor CGP53353, or by expression of a dominant-negative PKCbetaII, markedly impaired the ability of FUS to bind DNA. Suppression of FUS expression in myeloid precursor 32Dcl3 cells transfected with a FUS antisense construct was associated with upregulation of the granulocyte-colony stimulating factor receptor (G-CSFR) and downregulation of interleukin-3 receptor (IL-3R) beta-chain expression, and accelerated G-CSF-stimulated differentiation. Downregulation of FUS expression in BCR/ABL-expressing 32Dcl3 cells was associated with suppression of growth factor-independent colony formation, restoration of G-CSF-induced granulocytic differentiation and reduced tumorigenic potential in vivo. Together, these results suggest that FUS might function as a regulator of BCR/ABL leukemogenesis, promoting growth factor independence and preventing differentiation via modulation of cytokine receptor expression. 相似文献