VLBI-SLR Combination Solution Using GEODYN

We would like to generate a multi-technique solution combining all of the geodetic techniques (VLBI, SLR, GPS, and DORIS) using the same software and using the same a priori models. Here we use GEODYN software and consider only the VLBI-SLR combination. Here we report initial results of our work on the combination. We first performed solutions with GEODYN using only VLBI data and found that VLBI EOP solution results produced with GEODYN agree with results using CALC/SOLVE at the 1-sigma level. We then combined the VLBI normal equations in GEODYN with weekly SLR normal equations for the period 2007-2008. Agreement of estimated Earth orientation parameters with IERS C04 were not significantly different for the VLBI-only, SLR-only, and VLBI+SLR solution

Towards the GEOSAT Follow-On Precise Orbit Determination Goals of High Accuracy and Near-Real-Time Processing

The US Navy's GEOSAT Follow-On spacecraft (GFO) primary mission objective is to map the oceans using a radar altimeter. Satellite laser ranging data, especially in combination with altimeter crossover data, offer the only means of determining high-quality precise orbits. Two tuned gravity models, PGS7727 and PGS7777b, were created at NASA GSFC for GFO that reduce the predicted radial orbit through degree 70 to 13.7 and 10.0 mm. A macromodel was developed to model the nonconservative forces and the SLR spacecraft measurement offset was adjusted to remove a mean bias. Using these improved models, satellite-ranging data, altimeter crossover data, and Doppler data are used to compute both daily medium precision orbits with a latency of less than 24 hours. Final precise orbits are also computed using these tracking data and exported with a latency of three to four weeks to NOAA for use on the GFO Geophysical Data Records (GDR s). The estimated orbit precision of the daily orbits is between 10 and 20 cm, whereas the precise orbits have a precision of 5 cm

SLR Station Recovery, Center of Frame Motion, and Time Varying Gravity

Weekly station position estimates, beginning with 1993, are derived from the ITRF2008-based SLR processing of up to four satellites: Lageos 1, Lageos2, Starlette, and Stella. Helmert parameters obtained from c omparison of weekly SLR station positions and the a-priori SLRF2008 station complement are evaluated for geocenter motion and scale. Two me thods for modeling time varying gravity are employed in the SLR satel lite POD processing, with GGM03S serving as the static gravity field. Both methods forward model atmosphere gravity derived from 6-hour ECM WF pressure data. The standard approach applies an annual 20x20 field estimated from 4 years of GRACE data, and the IERS2003 recommended linear rates for C20, C30, C40, C21, and S21. The alternate approach us es a new set of low-order/degree 4x4 coefficients estimated weekly fr om SLR & DORIS processing to 10 satellites from 1993-2012. This exper imental tvg4x4 model has been shown to improve the TOPEX, Jason-1, and Jason-2 altimeter satellite orbits,. In this paper we apply the more detailed time-variable gravity modeling to the SLR satellite POD pro cessing and subsequent reference frame analyses. For this study we will evaluate the orbit differences (periodic and secular) for the satel lites concerned, characterize the impact on the station coordinate solutions, and the impact on reference frame parameters (geocenter and s cale)

Time Variable Gravity modeling for Precise Orbits Across the TOPEX/Poseidon, Jason-l and Jason-2 Missions

Modeling of the Time Variable Gravity (TVG) is believed to constitute one of the the largest remaining source of orbit error for altimeter satellite POD. The GSFC operational TVG model consists of forward modeling the atmospheric gravity using ECMWF 6-hour pressure data, a GRACE derived 20x20 annual field to account for changes in the hydrology and ocean water mass, and linear rates for C20, C30, C40, based on 17 years of SLR data analysis (IERS 2003) using the EIGEN-GL04S1 (a GRACE+Lageos-based geopotential solution). Although the GSFC Operational model can be applied from 1987, there may be long-term variations not captured by these linear models, and more importantly the linear models may not be consistent with more recent surface mass trends due to global climate change, We have evaluated the impact of TVG in two different wavs: (1) by using the more recent EIGEN-6S gravity model developed by the GFZ/GRGS tearm, which consists of annual, semi-annual and secular changes in the coefficients to 50x50 determined over 8(?) years of GRACE+Lageos+GOCE data (2003-200?): (2) Application of 4x4 solutions developed from a multi satellite SLR+DORIS solution based on GGM03S that span the period from 1993 to 2011. We have evaluated the recently released EIGEN6s static and time-varying gravity field for Jason-2 (J2). Jason-I (J1), and TOPEX/Posiedon (TP) Precise Orbit Determination (POD) spanning 1993-2011. Although EIGEN6s shows significant improvement for J2POD spanning 2008 - 2011, it also shows significant degradation for TP POD from 1992. The GSFC 4x4 time SLR+DORIS-based series spans 1993 to mid 2011, and shows promise for POD. We evaluate the performance of the different TVG models based on analysis of tracking data residuals use of independent data such as altimeter crossovers, and through analysis of differences with internally-generated and externally generated orbits

The Grizzly, December 9, 1983

Ursinus Continues Excellence in Chemistry • Letters to the Editor • Heads\u27 Album Hits Charts • Aquabears Triumphant in Warrender\u27s Last Meet • Women\u27s Basketball Hustles to Two Victories • Mercer Wins Fencing Tourney • Thoma Leads Bears Over Haverfordhttps://digitalcommons.ursinus.edu/grizzlynews/1110/thumbnail.jp

The Impact of Temporal Geopotential Variations on GPS

Lemoine et al. (2006) and Lemoine et al. (2010) showed that applying more detailed models of time-variable gravity (TVG) improved the quality of the altimeter satellite orbits (e.g. TOPEX/Poseidon, Jason-1, Jason-2). This modeling include application of atmospheric gravity derived from 6-hrly pressure fields obtained from the ECMWF and annual gravity variations to degree & order 20x20 in spherical harmonics derived from GRACE data. This approach allowed the development of a consistent geophysical model for application to altimeter satellite orbit determination from 1993 to 2011. In addition, we have also evaluated the impact of TVG modeling on the POD of Jason-1 and Jason-2 by application of a weekly degree & order four gravity coefficient time series developed using data from ten SLR & DORIS-tracked satellites from 1993 to 2011 (Lemoine et al., 2011)

Stimulated emission and lasing in π-conjugated polymer films, microstructures and opal photonic crystals

SPIE's International Symposium on Optical Science, Engineering, and Instrumentation, 1999, Denver, CO, United StatesZ. Valy Vardeny, Sergey V. Frolov, Douglas Chinn, Maxim N. Shkunov, Werner Gellermann, Katsumi Yoshino, Akihiko Fujii, Richard V. Gregory, Ray H. Baughman, and Anvar A. Zakhidov "Stimulated emission and lasing in π-conjugated polymer films, microstructures, and opal photonic crystals", Proc. SPIE 3797, Organic Light-Emitting Materials and Devices III, (17 December 1999). DOI: https://doi.org/10.1117/12.37269

The Grizzly, March 23, 1984

Assault Attempt on Ursinus Female • Speaker Gives Business Pointers • Forced Bussing in Wismer • New Course for Comm Arts Minor • Letters to the Editor • 1984 Fraternity Pledging Ends • New Fine Arts Course Planned for Fall • In my Opinion: Pledging Should be Banned • Meistersingers Give Return Performance • UC Sponsors Science Competition • Dr. Clouser Delivers Goethe Lecture • Lift-A-Thon Raises Funds for New Equipment • Bear Blades Remain Undefeated • Housing Changes Imminent • Orchestra Presents Bach Festival • Aquabears Conclude Best Season Ever • Batsmen Victorious in Opener • Men\u27s Lacrosse Optimistic • Track Team Looking Solidhttps://digitalcommons.ursinus.edu/grizzlynews/1115/thumbnail.jp

Cancer stem cells: Mediators of tumorigenesis and metastasis in head and neck squamous cell carcinoma

BackgroundCancer stem cells (CSCs) represent a subpopulation of cells responsible for tumor growth. Their role in head and neck squamous cell carcinoma (HNSCC) tumorigenesis and metastasis remains uncertain.MethodsWound healing and an orthotopic animal model were used to study cells expressing the CSC phenotype (CD44high and aldehyde dehydrogenase [ALDH]+) and assess mobility, tumorigenesis, and metastasis. A prospective collection of 40 patient‐derived primary HNSCC specimens were analyzed for CSC‐proportion compared to clinical variables.ResultsCSCs exhibited significantly faster wound closure and greater tumorigenesis and regional metastasis in vivo than non‐CSCs. In primary patient tumors, size and advanced stage were correlated with elevated proportion of CSCs, however, not with survival.ConclusionHNSCC stem cells mediate tumorigenesis and regional metastasis in vivo. In primary patient tumors, CSC‐proportion was associated with tumor size and stage, but not with metastatic spread or survival. CSC burden alone may only represent a minor variable in understanding CSCs and metastasis. © 2014 Wiley Periodicals, Inc. Head Neck 37: 317–326, 2015Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110728/1/hed23600.pd

Global and Local Gravity Field Models of the Moon Using GRAIL Primary and Extended Mission Data

The Gravity Recovery and Interior Laboratory (GRAIL) mission was designed to map the structure of the lunar interior from crust to core and to advance the understanding of the Moon's thermal evolution by producing a high-quality, high-resolution map of the gravitational field of the Moon. The mission consisted of two spacecraft, which were launched in September 2011 on a Discovery-class NASA mission. Ka-band tracking between the two satellites was the single science instrument, augmented by tracking from Earth using the Deep Space Network (DSN)