2,368 research outputs found
Letter from Yosh and Irene [Kuromiya] to Michi Weglyn
No full textA letter from Yosh and Irene [Kuromiya] asking Michi Weglyn for materials to create "a pictorial history of the life of Michi Nishiura Weglyn photos and documents" for the tribute to Michi Weglyn on February 21, 1998.These materials are from box 73 and 74 of the Frank Chin Papers. The Frank Chin Papers contain personal and professional correspondence between Frank Chin and Michi Weglyn relating to particular projects on which either author was working as well as files related to the Day of Remembrance Tribute to Michi Weglyn
Probing the solar corona with Doppler and range measurements of the spacecraft BepiColombo
No full textThe Mercury Orbiter Radio-science Experiment (MORE), onboard the ESA-JAXA mission BepiColombo, is dedicated to the study of Mercury’s interior structure and rotational state, and to fundamental physics tests. The MORE radiotracking system relies on a multi-frequency radio link: the onboard Deep Space Transponder receives an uplink in X-band and retransmits it back coherently in X- and Ka-band, the Ka-band transponder allows to establish a two-way link in Ka- band.
During the cruise phase, BepiColombo experienced four superior solar conjunctions. These periods, spanning for 15 days centered about the minimum impact parameter of the radio path between the spacecraft and the Earth, are exploited for tests of relativistic delay and Doppler shift. Thanks to the multi-frequency link the signal due to the solar corona plasma can be isolated through precise calibrations, exploiting the dispersive nature of the plasma1,2. This allows MORE to remove the plasma noise from the Doppler and range data in order to perform the fundamental physics test, but also to characterize the inner solar corona.
In this work we focus on the analysis of the data from the first (10th-24th March 2021) and second (29th January - 12th February 2022) solar conjunction experiments to characterize the properties of the solar wind.
For each radiotracking pass the power spectral density of Doppler measurements is compared with the expected power spectral index of a Kolmogorov turbulence (f-2/3)3.
Solar corona plasma data are also used to localize the plasma structures of the solar corona along the line of sight by means of cross-correlations between uplink and downlink time series of the plasma content obtained from Doppler data. This allows us to analyze in more detail large solar phenomena, such as coronal mass ejections.
Exploiting the collected open-loop recordings at high frequency (4 kHz), the solar wind velocity can be estimated assuming a theoretical model for the intensity spectrum4. The intensity timeseries are used to fit theoretical spectrum parameters (amplitude, velocity, axial ratio, inner scale of turbulence and power law index), characterizing the solar wind in the vicinity of the Sun.
Finally, the range data set allows us to retrieve the total electron content along the radio path. This absolute measurement is used to adjust models of the solar wind density beyond four solar radii
The Mindful Christian with Irene Kraegel
No full textOur guest for this episode is Irene Kraegel, the author of The Mindful Christian. We examine how Christian life is enhanced by mindfulness
Context-dependent regulation of embryonic stem cell differentiation by mGlu4 metabotropic glutamate receptors
No full textThe mGlu5 receptor is the only metabotropic glutamate receptor subtype expressed by mouse embryonic stem (ES) cells grown under non-differentiating conditions [Cappuccio, L, Spinanti, P. Porcellini, A., Desiderati, F., De Vita, T., Storto, M., Capobianco, L., Battaglia, G., Nicoletti, F., Melchiorri, D., 2005. Endogenous activation of mGlu5 metabotropic glutamate receptors supports self-renewal of cultured mouse embryonic stem cells. Neuropharmacology 1, 196-205]. We now report that ES cells differentiating into embryoid bodies (EBs) progressively lose mGlu5 receptors and begin to express mGlu4 receptors at both mRNA and proteinc level. A 4-day treatment of EBs with the mGlu4 receptor agonist, L-2-amino-4-phosphonobutanoate (L-AP4), increased mRNA levels of the mesoderm marker, brachyury and the endoderm marker, H19, and decreased the expression of the transcript for the primitive ectoderm marker, fibroblast-growth factor-5 (FGF-5). These effects were prevented by the mGlu4 receptor antagonists, alpha-methylserine-O-phosphate (MSOP). Plating of EBs for 4 days in vitro in ITSFn medium induced cell differentiation towards a neural lineage, as reflected by the expression of the intermediate filament protein, nestin, and the homeobox protein, Dlx-2. Pharmacological activation of mGlu4 receptors during cell incubation in ITSFn medium increased the expression of both neural markers. Similar results were obtained when neural differentiation was induced by exposure of EBs to retinoic acid. These data suggest that differentiation of cultured ES cells is associated with chances in the expression pattern of mGlu receptors and that activation of mGlu4 receptors affects cell differentiation in a context-dependent manner. (c) 2006 Elsevier Ltd. All rights reserved
Comparison of plasma calibration techniques to enhance radiometric observables performance: BepiColombo MORE test case
No full textRadio science experiments on board a spacecraft aim at investigating different fields of physics, including the study of gravity field and geodesy of a planetary body, test of general relativity and atmospheric studies. In this work we focus on improving the quality of radiometric observables by analyzing different techniques to calibrate the dispersive noise.
The primary source of the dispersive medium for interplanetary missions is the solar corona plasma, with the Earth ionosphere contributing to a lesser extent. In order to isolate the dispersive contribution, a multifrequency radio system is generally adopted. In the state-of-the-art calibration scheme (Bertotti, et al., 1993) three 2-way links are established. The system of equations of the calibration scheme is composed of three equations function of three observables and three unknowns, namely the non-dispersive observable and the uplink and downlink plasma contribution. This study is performed with the BepiColombo Mercury Orbiter Radio science Experiment (MORE) data collected during superior solar conjunction experiments. The MORE radio-tracking system simultaneously supports coherent radio links in X/X, X/Ka, and Ka/Ka bands.
Not all spacecraft are equipped with a complete radio link due to the required hardware complexity; hence, this work aims at characterizing the performances of alternative calibration schemes. The incomplete dual link calibration consists of only two observables with three unknowns; thus, it is not possible to determine both the uplink and downlink plasma contribution. However, a linear combination of the observables can be used to compensate for one of the two plasma contribution (uplink or downlink). This calibration schemes can be applied to the different link pairs, i.e., X/X + Ka/Ka, X/Ka + Ka/Ka, and X/X + X/Ka.
Moreover, the single link Differenced Range Versus Integrated Doppler (DRVID) technique is implemented (MacDoran, 1970) and the results are compared with the ones obtained from triple and dual link configurations.
The accuracy of the various calibration techniques is evaluated for both Doppler and range data by comparing the residuals’ standard deviation, root mean square, mean value, and Allan deviation or Power Spectral Density
Capitolo Genetica, Metodi di Produzione e Ripopolamento: Problemi genetici nella produzione in allevamento di fagiani di qualità (Phasianus colchicus L.)
No full text
Loewenfeld Table 9-3: Work on the Relations Between Iris Structure and Pupillary Movements
No full textTable 9-3, \u27Work on the relation between iris structure and pupillary movements,\u27 in "The Pupil" by Irene E. Loewenfeld. Includes Year, Author, and Species used in experimentation.Loewenfeld, Irene (1993) \u27Table 9-3: Work on the relations between iris structure and pupillary movements.\u27 The Pupil: Anatomy, Physiology, and Clinical Applications. Vol I. pp 418. Wayne State University Press. Detroit: Mich
Irene School District No. 3405
No full textPhotograph - A view of Irene School building, Alberta. ATS 7-65-12-W
Irene Smalls
No full textIrene Smalls leading a music program for her book at the Main Library.
Irene Smalls (1950- ) is an award-winning children's author. Her book "Irene Jennie and the Christmas Masquerade" describes an old holiday custom celebrated along the Cape Fear. Slaves in Wilmington, NC and plantations would dress up in costumes around Christmas and New Year's to parade from house to house. Scholars believe this tradition came with the slaves from their West African roots. The "Jonkonnu" celebration continues in Bermuda, but died out in Wilmington after the Civil War. The tradition was picked up by white youngsters who dressed up for "Koonering" in Wilmington until around World War I
- …
