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Observations of a lunar ''horizon glow' by several Surveyor spacecraft on the lunar surface in the 1960s and detections of dust particle impacts by the Apollo 17 Lunar Ejecta and Meteoroid Experiment have been explained as the result of micron-sized charged particles lifting off the surface. The surface of the Moon is exposed to the solar wind and solar UV radiation causing photoemission, so it develops a surface charge and an electric field near the surface. Dust particles injected into this plasma from the lunar regolith, whether from human and mechanical activity or from meteoroid impacts or electrostatic forces, may be stably levitated above the surface and may undergo preferential deposition onto areas of the lunar surface (or equipment) with different electrical properties. This can lead to a net transport as well as contamination of sensitive equipment. This paper reports on new experimental measurements and numerical simulations of the plasma environment above the lunar surface and the related behavior of charged dust. DOI: 10.1061/(ASCE)0893-1321(2009)22:1(2) CE Database subject headings: Moon; Dust; Spacecraft: Space exploration.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cell.2008.07.040 Byline: Tugba Guven-Ozkan (1), Yuichi Nishi (1), Scott M. Robertson (1), Rueyling Lin (1) Keywords: CELLBIO; DEVBIO; DNA Abstract: In C. elegans, four asymmetric divisions, beginning with the zygote (P0), generate transcriptionally repressed germline blastomeres (P1-P4) and somatic sisters that become transcriptionally active. The protein PIE-1 represses transcription in the later germline blastomeres but not in the earlier germline blastomeres P0 and P1. We show here that OMA-1 and OMA-2, previously shown to regulate oocyte maturation, repress transcription in P0 and P1 by binding to and sequestering in the cytoplasm TAF-4, a component critical for assembly of TFIID and the pol II preinitiation complex. OMA-1/2 binding to TAF-4 is developmentally regulated, requiring phosphorylation by the DYRK kinase MBK-2, which is activated at meiosis II after fertilization. OMA-1/2 are normally degraded after the first mitosis, but ectopic expression of wild-type OMA-1 is sufficient to repress transcription in both somatic and later germline blastomeres. We propose that phosphorylation by MBK-2 serves as a developmental switch, converting OMA-1/2 from oocyte to embryo regulators. Author Affiliation: (1) Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA Article History: Received 13 December 2007; Revised 18 April 2008; Accepted 16 July 2008 Article Note: (miscellaneous) Published: October 2, 2008

A portfolio is a well-organized document containing critical analyses and evidence related to a coach's background, context(s) of coaching, approach to coaching, coaching accomplishments, and goals for further development. Here, the authors describe different types of coaching portfolios as well as strategies for developing a coaching portfolio. In their research with youth soccer coaches and sport leaders from a wide range of physical activity settings, they found that coaching portfolios encourage coaches to dialogue with one another, practice reflection, pursue professional development goals, and use player-focused portfolios with their own teams. Among other things, they mention that there are drawbacks to developing and using coaching portfolios. (Contains 3 tables.)

Overseas field trips, when they are well planned, offer numerous benefits to young athletes. They contribute to player development, and fuel the team's energy and commitment to success. Field trips are enjoyable and exciting breaks from the regular routine of training and competing. The authors recommend strategies for positive results based on their own experience in taking a boys' soccer team (from Canada) to England. An organizational structure is provided, along with practical ideas for designing and implementing a successful experience. Among other things, the authors discusses that needs assessment, planning, and funding should be taken into consideration. (Contains 2 tables and 1 figure.)

Experimental investigations are reported on the charging of dust particles resting on conducting and insulating surfaces beneath plasma. The experiment is configured to give insight into the behavior of dust on planetary surfaces exposed to solar wind plasma. In the experiments, the surfaces are agitated so that the particles drop through a small hole into a Faraday cup that measures the charge on each dust particle. Both conducting (Ni) and insulating dusts (Si[O.sub.2], [Al.sub.2][O.sub.3] and JSC-1 lunar regolith simulant) are investigated. The conducting surface is given a bias voltage above the floating potential to create conditions in which the electron flux is dominant or a bias voltage below the floating potential for which the ion flux is dominant. The dust charges more positively in ion-flux-dominant conditions and more negatively in electron-flux-dominant conditions. The insulating dusts retain the charge for a long period of time (> 1 h) after the plasma is turned off. The charge decays more quickly if the surface is agitated, causing the dust to roll around, or if there is ultraviolet illumination. The conducting dust often has a lower level of charge than the insulating dust because the charge is conducted from the dust particle into the conducting surface. Conducting and insulating dusts on an insulating surface have approximately the same level of charge. Index Terms--Dust grain, electron flux, Faraday cup, floating potential, ion flux, plasma charging.

The mesosphere is a naturally occurring complex plasma with nanometer-sized smoke particles from the ablation of meteors that remain aloft as a consequence of their low rate of sedimentation. Methods are discussed for creating and diagnosing a relatively uniform smoky plasma in the laboratory for the purpose of investigating mesospheric physics. Metallic particles, a few nanometers in radius, are created by evaporation of metal into an inert carrier gas. The particles are transported by gas flow into a double plasma device, where they are charged by the plasma and confined by the plasma potential. Physics issues for the mesosphere that may be investigated include the origins of positively charged smoke particles and of fluctuating electric fields that have been observed by rocket-borne probes. Index Terms--Ionosphere, plasma devices, plasmas.

The study of a cylindrical Langmuir probe in low-density, collisionless, plasma, which is scanned radially through the presheath region, is employed to describe the effects of distance from the axis on the current-voltage characteristics. The results show that the plasma potential from the Langmuir probe characteristics is nearly constant, where as the plasma potential from an emissive probe exhibits a parabolic profile.

The plasma-sheath problem is solved numerically for the transition regime from collisionless to strongly collisional in both planar and cylindrical geometry. An improved frequency for ion-neutral momentum transfer collisions is introduced as a combination of the constant collision frequency and constant mean free path models. The model is correct in the limiting cases of collisionless and strongly collisional plasmas. The current density at the wall is calculated for a wide range of parameters and an analytic form J = [J.sub.0]/[(1 + [kappa]L/[lambda]).sup.1/2] is found to describe the reduction of the flux, where [J.sub.0] the ion flux for the collisionless case, L is the dimension of the plasma, [lambda] is the ion-neutral mean free path, and k is a fitting parameter. Index Terms--Particle collisions, plasma modeling, plasma sheaths.

Four types of electron density measurements are compared in the same device: cylindrical probe, disk probe, microwave cavity, and microwave hairpin. The measurements are made in hot-filament discharges in a soup-pot type of plasma device with and without multidipolar surface magnetic fields with densities up to 1 x [10.sup.9] [cm.sup.-3] and electron temperatures of 0.1-1.3 eV. The cylindrical probe and hairpin give densities that are in close agreement for all conditions. The density from the cylindrical probe, hairpin, and cavity measurements are in good agreement ([less than or equal to] 12 % difference) in plasma without magnetic containment. With magnetic containment, the different methods give greater differences in the densities ([less than or equal to]30%), perhaps as a result of the higher fraction of energetic electrons. For all conditions, the densities from the disk probe are lower than the densities from the other methods. Index Terms--Plasma devices, plasma measurements, plasma sheaths.

Electron energy balance is shown to play an important role in determining the plasma potential in low-density hot-filament discharges. The confined electrons that are lost to the walls are those with energy just above the plasma potential, thus the electron energy loss rate is the product of the electron loss rate and the height of the potential barrier. The sources of the electron energy are the energy at creation plus the energy gained from equilibration with energetic, unconfined electrons. An experiment in a soup-pot plasma device demonstrates that the plasma potential has values that satisfy the energy balance equation. The ion loss rate affects the electron loss rate through the quasi-neutrality condition, thus collisions of ions play a role in determining the plasma potential by reducing the particle loss rates. Index Terms--Plasma devices, plasma measurements, plasma sheaths.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2005.07.008 Byline: Premnath Shetty, Miao-Chia Lo, Scott M. Robertson, Rueyling Lin Keywords: Wnt; POP-1; Endoderm; C. elegans; TCF/LEF; [beta]-catenin Abstract: Canonical Wnt signaling converts the TCF/LEF transcription factor from repressor to activator by increasing nuclear levels of its coactivator, [beta]-catenin. A striking exception had been reported for Wnt-induced endoderm formation during C. elegans embryogenesis. It has long been believed that transcriptional activation of Wnt target genes in the endoderm precursor occurred due to a lowering of nuclear levels of the worm TCF/LEF protein, POP-1, effectively alleviating POP-1 repressive activity. Contrary to this model, we demonstrate here that POP-1 directly activates Wnt target genes in the endoderm precursor. Wnt converts POP-1 from a repressor to an activator, and this conversion requires that POP-1 nuclear levels be lowered in the endoderm precursor. We propose that the balance between TCF/LEF and coactivator(s), achieved by elevating coactivator levels (the canonical pathway) and/or reducing TCF/LEF levels (worm endoderm), determines Wnt signal strength. Author Affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, USA Article History: Received 29 June 2005; Revised 7 July 2005; Accepted 8 July 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2004.11.001 Byline: Joshua E. Colwell (a), Amanda A.S. Gulbis (b), Mihaly Horanyi (a), Scott Robertson (c) Abstract: We investigate the electrostatic transport of charged dust in the photoelectron layer over the dayside surface of an asteroid. Micron-sized dust particles may be levitated above the surface in the photoelectron layer. Horizontal transport within the layer can then lead to net deposition of dust into shadowed regions where the electric field due to the photoelectron layer disappears. We apply a 2D numerical model simulating charged dust dynamics in the near-surface daytime plasma environment of Asteroid 433 Eros to the formation of dust deposits in craters. We find that dust tends to collect in craters and regions of shadow. This electrostatic dust transport mechanism may contribute to the formation of smooth dust ponds observed by the NEAR-Shoemaker spacecraft at Eros. The size distribution of transported dust depends on the particle density and work function, and the work function of the surface and solar wind electron temperature and density. With reasonable values for these parameters, [mu]m-sized and smaller particles are levitated at Eros. Micrometeoroid bombardment is not a sufficient source mechanism for electrostatic transport to create the Eros dust ponds. Laboratory measurements of dust in a plasma sheath show that dust launched off the surface by direct electrostatic levitation can provide a sufficient source for transport to produce the observed Eros ponds. Author Affiliation: (a) Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309-0392, USA (b) Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA (c) Center for Integrated Plasma Studies, University of Colorado, Boulder, CO 80309-0390, USA

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2004.09.015 Byline: Scott M. Robertson, Premnath Shetty, Rueyling Lin Keywords: Microarray; C. elegans; Embryos; skn-1; Lineage specific; Zygotic Abstract: During Caenorhabditis elegans embryogenesis, a maternally supplied transcription factor, SKN-1, is required for the specification of the mesendodermal precursor, EMS, in the 4-cell stage embryo. When EMS divides, it gives rise to a mesoderm-restricted precursor, MS, and an endoderm-restricted precursor, E. To systematically identify genes that function as key regulators of MS and/or E-derived tissues, we identified, by microarray analyses, genes that are newly transcribed within a short developmental window (approximately 30 min) encompassing the generation and fate specification of the MS and E blastomeres. By comparing total cDNAs generated from individual, carefully staged embryos, we identified 275 genes up-regulated in 12-cell embryos compared to 4-cell embryos. Fifty of these 275 genes are down-regulated in 12-cell skn-1 mutant embryos and are designated skn-1-dependent zygotic (sdz) genes. The spatial and temporal expression patterns in C. elegans embryos of 10 randomly selected sdz genes were analyzed by a nuclear GFP reporter driven by the endogenous 5' regulatory sequence of each gene. GFP expression, although absent at the 4-cell stage, was detected at the 12- to 16-cell stage for all 10 genes and was restricted to EMS-derived lineages for 7 of the 10. Among the seven lineage-specific genes, three genes are expressed equally in both MS and E lineages, two are expressed exclusively or predominantly in the MS lineage, and two are expressed exclusively in the E lineage. Depletion of skn-1 by RNAi abolishes the expression of all seven reporter transgenes in vivo, confirming that these genes are indeed skn-1 dependent. These results demonstrate the successful combination of single-staged embryo cDNAs, genetic mutants, and whole transcriptome microarray analysis to identify stage- and lineage-specific transcripts in early C. elegans embryos. Author Affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA Article History: Received 22 July 2004; Revised 7 September 2004; Accepted 9 September 2004

Two types of rocket-borne probes are described for detecting charged aerosol particles in the ionosphere. The first are flat charge-collecting surfaces on the skin of the rockets that have returned data in four experimental campaigns. The collection surfaces have permanent magnets behind them that shield the probes from electrons. Some of the probes also have an electrical bias to repel light, positive ions. The current that is recorded is thus from heavier charged aerosol particles. This heavy charge carrier current is converted to a charge number density. The second type of probe, under development, is an electrostatic mass analyzer in which different ranges of mass are collected within the payload on surfaces with different bias potentials. Index Terms--Aerosols, ionosphere, plasma measurements, rockets.

Inside the plasma sheath of a negatively charged dust grain, ions lose energy in occasional collisions with neutrals. Thus, trapped ions with negative energy may be created that contribute to the electrostatic shielding of the dust's charge. A kinetic model is solved for the fraction of the trapped ions in the Debye cloud as a function of dust size. The relative number of trapped ions in the Debye cloud reaches a maximum at dust size a/[[lambda].sub.D] [approximately equal to] 0.3[([T.sub.e]/[T.sub.i]).sup.-0.6), where [[lambda].sub.D] is the Debye length and Te and Ti are the electron and ion temperatures, respectively. More than 50% of Debye shielding may be due to ions that are trapped. Index Terms--Collisional processes, Debye shielding, dust charging, dusty plasma, trapped ions.

Stem cells are important in the maintenance and repair of adult tissues. A population of cells, termed side population (SP) cells, has stem cell characteristics as they have been shown to contribute to diverse lineages. In this study, we confirm that Abcg2 is a determinant of the SP cell phenotype. Therefore, we examined Abcg2 expression during murine embryogenesis and observed robust expression in the blood islands of the E8.5 yolk sac and in developing tissues including the heart. During the latter stages of embryogenesis, Abcg2 identifies a rare cell population in the developing organs. We further establish that the adult heart contains an Abcg2 expressing SP cell population and these progenitor cells are capable of proliferation and differentiation. We define the molecular signature of cardiac SP cells and compare it to embryonic stem cells and adult cardiomyocytes using emerging technologies. We propose that the cardiac SP cell population functions as a progenitor cell population for the development, maintenance, and repair of the heart. [c] 2003 Elsevier Inc. All rights reserved. Keywords: ATP-binding cassette transporter; Abcg2; Cardiac SP cells

Background: The Onduo virtual care program for people with type 2 diabetes (T2D) includes a mobile app, remote lifestyle coaching, connected devices, and telemedicine consultations with endocrinologists for medication management and prescription of real-time continuous glucose monitoring (RT-CGM) devices. In a previously described 4-month prospective study of this program, adults with T2D and baseline glycated hemoglobin (HbA1c) ≥8.0% to ≤12.0% experienced a mean HbA1c decrease of 1.6% with no significant increase in hypoglycemia. Objective: The objective of this analysis was to evaluate medication optimization and management in the 4-month prospective T2D study. Methods: Study participants received at least 1 telemedicine consultation with an Onduo endocrinologist for diabetes medication management and used RT-CGM intermittently to guide therapy and dosing. Medication changes were analyzed. Results: Of 55 participants, 48 (87%) had a medication change consisting of a dose change, addition, or discontinuation. Of these, 15 (31%) participants had a net increase in number of diabetes medication classes from baseline. Mean time to first medication change for these participants was 36 days. The percentage of participants taking a glucagon-like peptide-1 receptor agonist increased from 25% (12/48) to 56% (n=27), while the percentages of participants taking a sulfonylurea or dipeptidyl peptidase 4 inhibitor decreased from 56% (n=27) to 33% (n=16) and 17% (n=8) to 6% (n=3), respectively. Prescriptions of other antidiabetic medication classes including insulin did not change significantly. Conclusions: The Onduo virtual care program can play an important role in providing timely access to guideline-based diabetes management medications and technologies for people with T2D. [ABSTRACT FROM AUTHOR]