Vertical motions in the equatorial middle atmosphere

A single station vertical velocity equation which considers ageostrophic and diabatic effects derived from the first law of thermodynamics and a generalized thermal wind relation is presented. An analysis and verification procedure which accounts for measurement and calculation errors as well as time and space continuity arguments and theoretical predictions are described. Vertical velocities are calculated at every kilometer between 25 and 60 km and for approximately every three hours for the above diurnal period at Kourou (French Guiana), Fort Sherman (Panama Canal Zone), Ascension Island, Antigua (British West Indies) and Natal (Brazil). The results, plotted as time series cross sections, suggest vertical motions ranging in magnitude from 1 or 2 cm/sec at 30 km to as much as 15 cm/sec at 60 km. Many of the general features of the results agree well with atmospheric tidal predictions but many particular features suggest that both smaller time scale gravity waves (periods less than 6 hours) and synoptic type waves (periods greater than 1 day) may be interacting significantly with the tidal fields. The results suggest that vertical motions can be calculated for the equatorial middle atmosphere and must be considered a significant part of the motion for time scales from 8 to 24 hours

Borrowed alleles and convergence in serpentine adaptation

ACKNOWLEDGMENTS. We thank members of the L.Y. and K.B. laboratories for helpful discussions. This work was supported through the European Research Council Grant StG CA629F04E (to L.Y.); a Harvard University Milton Fund Award (to K.B.); Ruth L. Kirschstein National Research Service Award 1 F32 GM096699 from the NIH (to L.Y.); National Science Foundation Grant IOS-1146465 (to K.B.); NIH National Institute of General Medical Sciences Grant 2R01GM078536 (to D.E.S.); and Biotechnology and Biological Sciences Research Council Grant BB/L000113/1 (to D.E.S.)Peer reviewedPublisher PD

Toward Practical Non-Contact Optical Strain Sensing Using Single-Walled Carbon Nanotubes

Progress is reported in an emerging non-contact strain sensing technology based on optical properties of single-walled carbon nanotubes (SWCNTs). In this strain-sensing smart skin (“S4”) method, nanotubes are dilutely embedded in a thin polymer film applied to a substrate of interest. Subsequent strain in the substrate is transferred to the nanotubes, causing systematic spectral shifts in their characteristic short-wave infrared fluorescence peaks. A small diode laser excites a spot on the coated surface, and the resulting emission is captured and spectrally analyzed to deduce local strain. To advance performance of the method, we prepare S4 films with structurally selected SWCNTs. These give less congested emission spectra that can be analyzed precisely. However, quenching interactions with the polymer host reduce SWCNT emission intensity by an order of magnitude. The instrumentation that captures SWCNT fluorescence has been made lighter and smaller for hand-held use or mounting onto a positioning mechanism that makes efficient automated strain scans of laboratory test specimens. Statistical analysis of large S4 data sets exposes uncertainties in measurements at single positions plus spatial variations in deduced baseline strain levels. Future refinements to S4 film formulation and processing should provide improved strain sensing performance suitable for industrial application

Excitonic Effects and Optical Spectra of Single-Walled Carbon Nanotubes

Many-electron effects often dramatically modify the properties of reduced dimensional systems. We report calculations, based on an many-electron Green's function approach, of electron-hole interaction effects on the optical spectra of small-diameter single-walled carbon nanotubes. Excitonic effects qualitatively alter the optical spectra of both semiconducting and metallic tubes. Excitons are bound by ~ 1 eV in the semiconducting (8,0) tube and by ~ 100 meV in the metallic (3,3) tube. These large many-electron effects explain the discrepancies between previous theories and experiments.Comment: 6 pages, 3 figures, 2 table

Effects of pro-inflamatory cytokines on polarized rat parotid Par-C10 monolayers [abstract]

Abstract only availableSjögren's syndrome (SS), an autoimmune disorder, is distinguished by inflammation and salivary gland cell death, leading to xerostomia (dry mouth). The G protein-coupled P2Y2 receptor (P2Y2R) is up-regulated in response to damage or stress in salivary epithelium. Pro-inflammatory cytokines associated with SS can be produced by infiltrating lymphocytes or salivary epithelium. Correlations have been found between lymphocytic infiltration and increased production of pro-inflammatory cytokines such as interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-Éø (TNFα) and interferon-γ (IFNγ) and decreased function of exocrine glands in SS. Recent data has shown that P2Y2R activation enhances the activity of metalloproteases that release TNFα. OBJECTIVES: To study the effects of cytokines on polarized salivary epithelium. METHODS: Polarized rat parotid (Par-C10) monolayers were used to perform these studies. Cytokines released by UTP-induced P2Y2R activation were identified by ELISA. To evaluate the role of cytokines associated with SS on epithelial integrity, epithelial resistance was determined and correlated with the expression and distribution of tight junction (TJ) proteins by immunofluorescence and Western analysis, respectively. RESULTS: Activation of P2Y2Rs in Par-C10 monolayers induced the release of TNFα. The cytokines TNFα and IFNγ, but not IL-6 or IL1β, decreased the resistance of Par-C10 cells. However, the expression/distribution of the TJ protein ZO-1 was unaffected. CONCLUSIONS: The data support a hypothesis that P2Y2R expression and activation in salivary gland cells contribute to epithelial dysfunction in SS by generating pro-inflammatory cytokines that regulate ion transport and epithelial integrity in salivary glands. Future studies will determine the role of cytokines on the expression and distribution of other TJ molecules including occludin, claudins and junctional adhesion molecules. These studies may lead to better therapeutic strategies for minimizing autoimmune-associated dysfunction of salivary gland that contributes to xerostomia in SS patient.Life Sciences Undergraduate Research Opportunity Progra

Victoria Plaza Revisited: Lessons for the Evaluation of Housing for the Elderly

This monograph is based upon a workshop sponsored by the Institute on Aging and Environment at the 1994 EDRA Conference. San Antonio is the home of the first public housing facility specifically designed for older persons and the authors took the opportunity to reflect on the substantive and methodological issues that can be learned from Victoria Plaza. Frances Carp, who conducted the original longitudinal study, presents reflections on the early fray into Post Occupancy Evaluation and the lessons applicable today. Min Kantrowitz and Gerald Weisman present their comments and conclusions.https://dc.uwm.edu/caupr_mono/1020/thumbnail.jp