Resonance Raman spectra of wurtzite and zincblende CdSe nanocrystals

Resonance Raman spectra and absolute differential Raman cross-sections have been measured for CdSe nanocrystals in both the wurtzite and zincblende crystal forms at four excitation wavelengths from 457.9 to 514.5 nm. The frequency and bandshape of the longitudinal optical (LO) phonon fundamental is essentially identical for both crystal forms at each excitation wavelength. The LO phonon overtone to fundamental intensity ratio appears to be slightly higher for the wurtzite form, which may suggest slightly stronger exciton-phonon coupling from the Fröhlich mechanism in the wurtzite form. The LO fundamental Raman cross-sections are very similar for both crystal forms at each excitation wavelength. © 2012 Elsevier B.V. All rights reserved

Late Time Barium Cloud Striations and Their Possible Relationship to Equatorial Spread F

An active experiment has been conducted in space that allows a test for the theory of nonlinear development of striations in large barium clouds. The results are in excellent agreement with a computer simulation of the ExB instability reported by Scannapiecoe t al. (1976). The power law irregularity spectrum predicted by the theory and verified by the experiment is shown here to be due to wave steepeninga nd not_top lasmat urbulence.T he barium cloud resultsa re remarkably similar to bottomside equatorial spread F. A possible role of the E x B instability in bottomside equatorial spread F is discussed as a supplement to the Rayleigh-Taylor instability during the postsunset rise of the F layer and during anomalousp lasma uplifts which occur during geomagneticallya ctive period

Supermassive Black-hole Demographics & Environments With Pulsar Timing Arrays

Precision timing of large arrays (>50) of millisecond pulsars will detect the nanohertz gravitational-wave emission from supermassive binary black holes within the next ~3-7 years. We review the scientific opportunities of these detections, the requirements for success, and the synergies with electromagnetic instruments operating in the 2020s.Comment: Submitted to the Astro2020 Decadal Survey. One of 5 core white-papers authored by members of the NANOGrav Collaboration. 9 pages, 2 figure

"Bag of tricks" for EFNEP youth program

"November, 1972

Crit II Electric, Magnetic, and Density Measurements Within an Ionizing Neutral Stream

Measurements from rocket borne sensors inside a high velocity neutral barium beam show a factor of six increasei n plasmad ensityi n a movingi onizingf ront. This region-wacso -locatedw ith intensef luctuatinge lectric fields( $E • 300m V/m) at frequenciewse llu ndert he lower hybrid frequency for a barium plasina. Large quasi-DC electric and magnetic field fluctuations were also detected with a large componento f the current and the electricf ield. parallelt o Bo. An Alfv6n wavew ith a finite electricf ield componentp arallel to the geomagneticfi eld was observed to propagatea longB o, wherei t wasd etectedb y ami nstrumented sub-payload

5G NR Positioning Enhancements in 3GPP Release-18

New radio (NR) positioning in the Third Generation Partnership Project (3GPP) Release 18 (Rel-18) enables 5G-advanced networks to achieve ultra-high accuracy positioning without dependence on global navigation satellite systems (GNSS) with key enablers such as the carrier phase positioning technique, standardized for the first time in a cellular communications standard and setting a new baseline for future generations. In addition, Rel-18 NR supports positioning functionalities for reduced capability (RedCap) user equipment and bandwidth aggregation for positioning measurements. Moreover, the low power solutions are designed for low power high accuracy positioning use cases. Lastly, sidelink-based positioning is introduced in Rel-18. This article constitutes a comprehensive treatment of the Rel-18 NR positioning enhancements crucial for the development of next-generation networks

Simultaneous Rocket-Borne Beacon and In Situ Measurements of Equatorial Spread F - Intermediate Wavelength Results

A high-performancero cketc arryinga four-frequencyp, hase-coherenbt eacona nd full complemento f in situ diagnostici nstrumentationw as launchedi nto active equatorial spreadF on July 17, 1979. In this paper we report the resultso f spectrallya nalyzingt he beaconp hase-scintillationa nd Langmuir probe data. By using simultaneousb ackscatterd ata from the Altair radar we were able to establisht hat the scintillation develops in high-density regions adjacent to the prominent plume structures and associated depletionsIn. theseh igh-densitrye gionsth e in situs pectras howa pronouncecdh angein the powerl aw slopen ear a spatialw avelengtho f 500 m. Larger scales tructuresa dmit a systematicallyv arying power law index that is generally less than 2, in good agreement with a large body of Wideband satellite data and recently analyzed Atmospheric Explorer E data. Smaller-scale structures admit a spectral index muchl argert han2 . A singleo, verallp owerl aw neark - 2 wasf oundo nlyi n low-densitrye gionsth at did not contributes ignificantlyt o the scintillation.T he resultsp resentedh ere and in a companionp aper suggestt hat refinementsin the current theorieso f equatorials preadF near and above the F region peak are needed

X Chromosome Sites Autonomously Recruit the Dosage Compensation Complex in Drosophila Males

It has been proposed that dosage compensation in Drosophila males occurs by binding of two core proteins, MSL-1 and MSL-2, to a set of 35–40 X chromosome “entry sites” that serve to nucleate mature complexes, termed compensasomes, which then spread to neighboring sequences to double expression of most X-linked genes. Here we show that any piece of the X chromosome with which compensasomes are associated in wild-type displays a normal pattern of compensasome binding when inserted into an autosome, independently of the presence of an entry site. Furthermore, in chromosomal rearrangements in which a piece of X chromosome is inserted into an autosome, or a piece of autosome is translocated to the X chromosome, we do not observe spreading of compensasomes to regions of autosomes that have been juxtaposed to X chromosomal material. Taken together these results suggest that spreading is not involved in dosage compensation and that nothing distinguishes an entry site from the other X chromosome sites occupied by compensasomes beyond their relative affinities for compensasomes. We propose a new model in which the distribution of compensasomes along the X chromosome is achieved according to the hierarchical affinities of individual binding sites

Molecular analysis of endocrine disruption in hornyhead turbot at wastewater outfalls in southern california using a second generation multi-species microarray.

Sentinel fish hornyhead turbot (Pleuronichthysverticalis) captured near wastewater outfalls are used for monitoring exposure to industrial and agricultural chemicals of ~ 20 million people living in coastal Southern California. Although analyses of hormones in blood and organ morphology and histology are useful for assessing contaminant exposure, there is a need for quantitative and sensitive molecular measurements, since contaminants of emerging concern are known to produce subtle effects. We developed a second generation multi-species microarray with expanded content and sensitivity to investigate endocrine disruption in turbot captured near wastewater outfalls in San Diego, Orange County and Los Angeles California. Analysis of expression of genes involved in hormone [e.g., estrogen, androgen, thyroid] responses and xenobiotic metabolism in turbot livers was correlated with a series of phenotypic end points. Molecular analyses of turbot livers uncovered altered expression of vitellogenin and zona pellucida protein, indicating exposure to one or more estrogenic chemicals, as well as, alterations in cytochrome P450 (CYP) 1A, CYP3A and glutathione S-transferase-α indicating induction of the detoxification response. Molecular responses indicative of exposure to endocrine disruptors were observed in field-caught hornyhead turbot captured in Southern California demonstrating the utility of molecular methods for monitoring environmental chemicals in wastewater outfalls. Moreover, this approach can be adapted to monitor other sites for contaminants of emerging concern in other fish species for which there are few available gene sequences

Experimental and mathematical study of the influence of growth factors and the kinetics of adult human articular chondrocytes

This study aimed at determining how kinetic parameters of adult human articular chondrocytes (AHAC) growth are modulated by the growth factor combination {\underline {T}}GF$\beta$1, {\underline {F}}GF-2, and {\underline {P}}DGF BB (TFP), recently shown to stimulate AHAC proliferation. AHAC, isolated from cartilage biopsies of three individuals, were cultured in medium without (CTR) or with TFP. For growth curves, AHAC were seeded at 1000 cells/cm$^{2}$ and cultured for 12 days, with cell numbers measured fluorimetrically in the same wells every 12 hours. For microcolony tests, AHAC were seeded at 2.5 cells/cm$^{2}$ and cultured for 6 days, with cell numbers determined for each microcolony by phase contrast microscopy every 8 hours. A mathematical model combining delay and logistic equations was developed to capture the growth kinetic parameters and to enable the description of the complete growth process of the cell culture. As compared to CTR medium, the presence of TFP increased the number of cells/well starting from the fifth day of culture, and a 4-fold larger cell number was reached at confluency. For single microcolonies, TFP reduced the time for the first cell division by 26.6\%, the time for subsequent cell divisions (generation time) by 16.8\%, and the percentage of quiescent cells by 42.5\%. The mathematical model fitted well the experimental data of the growth kinetic. Finally, using both microcolony tests and the mathematical model, we determined that prolonged cell expansion induces an enrichment of AHAC with shorter first division time, but not of those with shorter generation time