100,329 research outputs found
Probing and extracting the structure of vibrating SF6 molecules with inner-shell photoelectrons
Full text linkCitation: Nguyen, N. T., Lucchese, R. R., Lin, C. D., & Le, A. T. (2016). Probing and extracting the structure of vibrating SF6 molecules with inner-shell photoelectrons. Physical Review A, 93(6), 9. doi:10.1103/PhysRevA.93.063419We propose a scheme for probing the structure of vibrating molecules with photoelectrons generated from ultrashort soft-x-ray pulses. As an example we analyze below-100-eV photoelectrons liberated from the S(2p) orbital of vibrating SF6 molecules to image very small structural changes of molecular vibration. In particular, photoionization cross sections and photoelectron angular distributions (PAD) at nonequilibrium geometries can be retrieved accurately with photoelectrons near the shape resonance at 13 eV. This is achieved with a pump-probe scheme, in which the symmetric stretch mode is first Raman excited predominantly by a relatively short laser pulse and then later probed at different time delays by a few-femtosecond soft-x-ray pulse with photon energy near 200 eV
Threatened fishes of the world: Tanichthys albonubes Lin 1932 (Cyprinidae)
No full textThe white cloud mountain minnow Tanichthys albonubes Lin is an endemic species to southern China and the genus has two species, Tanichthys albonubes Lin and Tanichthys micagemmae Freyhof et Herder. The distribution range of T. albonubes Lin and T. micagemmae is very narrow and only found in the mountain brooks of Baiyunshan Mountain (White Cloud Mountain), Huaxian Country and the vicinity of Guangzhou in Guangdong Province and Halong, Quang Ninh Province, Vietnam respectively. The wild populations of this fish had already been on the verge of extinction when Shu-Yan Lin first discovered it in 1932 at the Baiyunshan Mountain. It was believed to be extinct in the wild because there were no reports of this fish in the wild since 1980. In September 2003, a small and isolated population of the fish was discovered in a mountain puddle in the north vicinity of Guangzhou. Additional studies are needed to determine the survival and propagation of the released fish. The protection of their natural habitat should be implemented.The white cloud mountain minnow Tanichthys albonubes Lin is an endemic species to southern China and the genus has two species, Tanichthys albonubes Lin and Tanichthys micagemmae Freyhof et Herder. The distribution range of T. albonubes Lin and T. micagemmae is very narrow and only found in the mountain brooks of Baiyunshan Mountain (White Cloud Mountain), Huaxian Country and the vicinity of Guangzhou in Guangdong Province and Halong, Quang Ninh Province, Vietnam respectively. The wild populations of this fish had already been on the verge of extinction when Shu-Yan Lin first discovered it in 1932 at the Baiyunshan Mountain. It was believed to be extinct in the wild because there were no reports of this fish in the wild since 1980. In September 2003, a small and isolated population of the fish was discovered in a mountain puddle in the north vicinity of Guangzhou. Additional studies are needed to determine the survival and propagation of the released fish. The protection of their natural habitat should be implemented
One dimensional lattice gases with rapidly decreasing interactions
No full textWe consider the pressure and the correlation functions of a one dimensional lattice gas in which the mutual interaction decreases as r exp-n t, (r, t>0), when the interparticle distance nrarrinfin. We prove that such a system cannot show phase transitions of order kgE1 in the sense that the pressure and the correlation functions are infinitely differentiable with respect to any relevant parameter (such as the temperature or the chemical potential)
Vascular endothelial growth factor restores delayed tumor progression in tumors depleted of macrophages
Full text linkGenetic depletion of macrophages in Polyoma Middle T oncoprotein (PyMT)-induced mammary tumors in mice delayed the angiogenic switch and the progression to malignancy. To determine whether vascular endothelial growth factor A (VEGF-A) produced by tumor-associated macrophages regulated the onset of the angiogenic switch, a genetic approach was used to restore expression of VEGF-A into tumors at the benign stages. This stimulated formation of a high-density vessel network and in macrophage-depleted mice, was followed by accelerated tumor progression. The expression of VEGF-A led to a massive infiltration into the tumor of leukocytes that were mostly macrophages. This study suggests that macrophage-produced VEGF regulates malignant progression through stimulating tumor angiogenesis, leukocytic infiltration and tumor cell invasion
LIN-1 sumoylation is required for ventral toroid contraction.
No full text(A) Wild-type and K10A, K169A mutant LIN-1::GFP expression in L3 larvae at the Pn.px stage after VPC-specific degradation of AID::SMO-1 from the L2 stage onward. The 1° and 2° VPC descendants are underlined in white. The left panels show the corresponding DIC images overlaid with the LIN-1::GFP signal in green. (B) Quantification of LIN-1::GFP expression levels in 1° and 2° VPC descendants at the Pn.px stage in LIN-1::GFP wild-type and K10A, K169A double mutants under the indicated conditions. See S3 Fig for the corresponding measurements at the Pn.pxx stage. (C) Toroid morphogenesis defects in LIN-1 K10A and K169A single and double mutants at the L4 stage. Left panels show lateral views of z-projections. vulA and vulB1 toroids are outlined by the white rectangle in the top left panel and shown in top (xz) views in the right panels. (D) Quantification of vulA contraction, calculated as the ratio of the vulA and vulB1 toroid diameter. The box plots show the median values with the 25th and 75th percentiles and the whiskers indicate the maximum and minimum values. Where indicated, untreated controls are labelled with–IAA (blue) and animals treated with 1 mM auxin with +IAA (red). In each graph, the numbers of animals scored are indicated by the numbers in brackets. Statistical significance in (B) and (D) was calculated with unpaired two-tailed t-tests. p-values are indicated as * p ≤ 0.05; ** p ≤ 0.01; *** p ≤ 0.001. The scale bars are 10 μm.</p
1993-1994 T. R. Pearson
No full textT. R. Pearson, a.k.a. Rick Gavin, was born in Winston-Salem, North Carolina. He was a student at North Carolina State University, where he gained a B.A. and M.A. in English. He was the first recipient of the John and Renée Grisham Writer in Residence Fellowship. He is the acclaimed author of fourteen novels, including A Short History of a Small Place and Warwolf, and a dozen screenplays. Top of the Rock is his fifth nonfiction book. He lives in Virginia and Brooklyn, New York. (Photo credit: Marian Young)https://egrove.olemiss.edu/grisham_res/1026/thumbnail.jp
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
Full text linkBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
SPATIAL CHOW-LIN METHODS: BAYESIAN AND ML FORECAST COMPARISONS
Full text linkCompleting data that are collected in disaggregated and heterogeneous spatial units is a quite frequent problem in spatial analyses of regional data. Chow and Lin (1971) (CL) were the rst to develop a uni ed framework for the three problems (interpolation, extrapolation and distribution) of predicting disaggregated times series by so-called indicator series. This paper develops a spatial CL procedure for disaggregating cross-sectional spatial data and compares the Maximum Likelihood and Bayesian spatial CL forecasts with the naive pro rata error distribution. We outline the error covariance structure in a spatial context, derive the BLUE for the ML estimator and the Bayesian estimation procedure by MCMC. Finally we
apply the procedure to European regional GDP data and discuss the disaggregation assumptions. For the evaluation of the spatial Chow-Lin procedure we assume that only NUTS 1 GDP is known and predict it at NUTS 2 by using employment and spatial information available at NUTS 2. The spatial neighborhood is de ned by the inverse travel time by car in minutes. Finally, we present the forecast accuracy criteria comparing the predicted values with the actual observations.
Letter from J. R. Eakin to Carl Hayden
No full textLetter from J. R. Eakin to Carl T. Hayden concerning access to Rowe Well and the canyon
Letter from J. R. Eakin to Stephen Mather
No full textLetter from J. R. Eakin to Stephen T. Mather about expenses and reconstruction of the Kaibab Trail
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