Clearing Things Up: A Vertical Mucus Clearance Assay to Investigate Rheological and Biochemical Parameters Governing Mucociliary Clearance.

Mucociliary clearance (MCC) plays an essential role to protect the airways from pathogens and pollutants. Impaired MCC leads to a host of diseases and initiates a cascade of chronic infection, inflammation, and reduced lung function. Understanding the mechanisms of clearance is a critical step in preventing and ultimately treating disease. The fundamental mechanisms guiding clearance are still poorly understood. Existing models have focused on fluid rheology, but haven't reached a consensus on which parameters govern the system. In this work I build an in vitro model capable of evaluating rheological and biochemical parameters and their effect on clearance. My model integrates the air-liquid interface (ALI) bronchial epithelial cell culture model with microfluidics to create a mucus clearance assay (MCA). Growing well-ciliated cells inside of a fluidics channel allows me to use external flow to investigate cilia-ASL interactions. I use external flow to build and validate a model of cilia hydrodynamics. Then I demonstrate external flow can be used as a force probe to investigate adhesion on the epithelial surface. Next I integrate the MCA with a tilting microscope to explore the effects of gravity on mucociliary clearance. Gravity has been largely ignored in mucus clearance experiments despite vertical transport in vivo and therapies exploiting gravitational drainage. I observe fluids transporting horizontally, but failing to transport when the cilia driven flow is opposed by gravity. This establishes gravitational effects as a necessary requirement for evaluating the parameters that govern MCC. Next I tested a 4.5% 1MDa PEG solution that matched the apparent viscosity of mucus and observed that unlike mucus, the PEG solution didn't transport vertically. This experiment demonstrates that viscosity alone is not a predictor of vertical transport. Finally I suggest that the inability to transport vertically is a result of the system dehydrating and posit that mucus' ability to transport vertically is the result of biochemical adhesion with the cilia.Doctor of Philosoph

Envisioning the Library’s Role in Scholarly Communication in the Year 2025

This research probes future roles for libraries in the scholarly communication process through the use of scenarios. The researchers asked 20 ARL library directors to read and provide constructive comments on the scenarios, name the scenarios, and either select a scenario that most closely matched their vision or propose a new scenario. The directors identified six possible futures. Issues such as library as publisher, the economy, and the need for collaboration are discussed, as well as the timeframe for such futures and the desire versus the likelihood of a particular scenario happening

Book Reviews

Reviews of the following books: Joe Scott, The Woodsman-Songmaker by Edward D. Ives; Legacy of a Lifetime: The Story of Baxter State Park by John W. Hakola; General William King: Merchant, Shipbuilder, and Maine\u27s First Governor by Marion Jaques Smith; Picture History of New England Passenger Vessels by W. Bartlett Cram; Colonial Massachusetts: A History by Benjamin Labaree

CSI 2264: Characterizing Accretion-Burst Dominated Light Curves for Young Stars in NGC 2264

Based on more than four weeks of continuous high cadence photometric monitoring of several hundred members of the young cluster NGC 2264 with two space telescopes, NASA's Spitzer and the CNES CoRoT (Convection, Rotation, and planetary Transits), we provide high quality, multi-wavelength light curves for young stellar objects (YSOs) whose optical variability is dominated by short duration flux bursts, which we infer are due to enhanced mass accretion rates. These light curves show many brief -- several hour to one day -- brightenings at optical and near-infrared (IR) wavelengths with amplitudes generally in the range 5-50% of the quiescent value. Typically, a dozen or more of these bursts occur in a thirty day period. We demonstrate that stars exhibiting this type of variability have large ultraviolet (UV) excesses and dominate the portion of the u-g vs. g-r color-color diagram with the largest UV excesses. These stars also have large Halpha equivalent widths, and either centrally peaked, lumpy Halpha emission profiles or profiles with blue-shifted absorption dips associated with disk or stellar winds. Light curves of this type have been predicted for stars whose accretion is dominated by Rayleigh-Taylor instabilities at the boundary between their magnetosphere and inner circumstellar disk, or where magneto-rotational instabilities modulate the accretion rate from the inner disk. Amongst the stars with the largest UV excesses or largest Halpha equivalent widths, light curves with this type of variability greatly outnumber light curves with relatively smooth sinusoidal variations associated with long-lived hot spots. We provide quantitative statistics for the average duration and strength of the accretion bursts and for the fraction of the accretion luminosity associated with these bursts.Comment: Accepted for publication in AJ. 39 pages; 6 tables; 25 figures, many of which are highly degraded to meet size limits. Please download the regular resolution version at http://web.ipac.caltech.edu/staff/amc/staufferetal2014.pd

On the universal outcome of star-formation: Is there a link between stars and brown-dwarfs?

(abridged) The recent evidence obtained by Briceno et al. that star-formation in Taurus-Auriga (TA) may be producing significantly fewer brown dwarfs (BDs) per star than the ONC is investigated by setting up a realistic model stellar plus BD population and explicitly taking into account a high binary proportion and dynamical evolution in the TA groups and the ONC. The Briceno result is reproduced almost exactly despite an identical IMF in both systems because many BD-BD and star-BD binaries are disrupted in the ONC thus freeing BDs, while the TA groups remain unevolved dynamically. However, the resulting populations do not have the correct star-star, star-BD and expecially BD-BD binary properties, even if a variable BD IMF is allowed for. The conclusion is therefore that BDs need to be added as a separate population which has its own binary properties. Such an extra population can have various origins which are briefly discussed in this contribution but more fully in an associated paper.Comment: MNRAS, accepted, 23 pages, 14 figures, LaTeX, two references adde

Investigation into the High Voltage Shutdown of the Oxygen Generator System in the International Space Station

The Oxygen Generation System (OGS) Hydrogen Dome Assembly Orbital Replacement Unit (ORU) serial number 00001 suffered a cell stack high-voltage shutdown on July 5, 2010. The Hydrogen Dome Assembly ORU was removed and replaced with the on-board spare ORU serial number 00002 to maintain OGS operation. The Hydrogen Dome Assembly ORU was returned from ISS on STS-133/ULF-5 in March 2011 with test, teardown and evaluation (TT&E) and failure analysis to follow

Pleasure, Health and Sociability. Food Fact and Food Choice through Iberian Ham

A medida que avanzan los estudios sobre el polisémico ámbito de la alimentación humana, resulta más necesario considerar mayor número de variables para analizar con solvencia el hecho alimentario. Más allá de los estudios sobre las fases de producción y distribución, nuestra propuesta se centra en la fase del consumo y trata de identificar los elementos que explican por qué las sociedades seleccionan y prefieren unos alimentos en detrimento de otros. Actualmente, la selección alimentaria está intrínsecamente presente en el hecho alimentario de las sociedades modernas, relegando a un segundo plano los factores biológicos y fisiológicos, en relación a parámetros dominantes comparados con el placer, la salud y la sociabilidad. Mediante una combinación de técnicas cuantitativas y cualitativas, este estudio propone la relevancia de dimensiones como el placer y la salud como elementos que guían a los consumidores para elegir un determinado producto gourmet, como es el caso del jamón ibérico en España.Esta investigación es el resultado del proyecto I+D (CSO2013-42468-P) del Ministerio de Economía y Competitividad Las marcas de calidad en el mundo rural: nuevos retos para productores y consumidores

An Improved Dynamical Model for the Microquasar XTE J1550-564

We present an improved dynamical model of the X-ray binary and microquasar XTE J1550-564 based on new moderate-resolution optical spectroscopy and near-infrared photometry. By combining our new radial velocity measurements with previous measurements obtained 2001 May at the 8.2m VLT and with light curves, we find an orbital period of P=1.5420333 +/- 0.0000024 days and a radial velocity semiamplitude of K_2=363.14 +/- 5.97$ km/sec, which together imply an optical mass function of f(M)=7.65 +/- 0.38 solar masses. We find that the projected rotational velocity of the secondary star is 55 +/- 5 km/sec, which implies a very extreme mass ratio of Q=M/M_2=30. Using a model of a Roche lobe-filling star and an azimuthally symmetric accretion disk, we fit simultaneously optical light curves from 2001, near-infrared light curves from 2008 and all of the radial velocity measurements to derive system parameters. We find an inclination of 74.7 +/- 3.8 deg and component masses of M_2=0.30 +/- 0.07 solar masses and M=9.10 +/- 0.61 solar masses for the secondary star and black hole, respectively. The radius of the secondary star for the adopted model is 1.75 +/- 0.12 solar radii. Using this radius, the average K_S magnitude, and an extinction of A_K=0.507 +/- 0.050 mag, we find a distance of 4.38^{+0.58}_{-0.41} kpc, which is in good agreement with a recent distance estimate based on HI absorption lines (abstract shortened).Comment: 29 pages, 11 figures, to appear in ApJ, figures 1 and 2 are compresse

Ecological expected utility and the mythical neural code

Neural spikes are an evolutionarily ancient innovation that remains nature’s unique mechanism for rapid, long distance information transfer. It is now known that neural spikes sub serve a wide variety of functions and essentially all of the basic questions about the communication role of spikes have been answered. Current efforts focus on the neural communication of probabilities and utility values involved in decision making. Significant progress is being made, but many framing issues remain. One basic problem is that the metaphor of a neural code suggests a communication network rather than a recurrent computational system like the real brain. We propose studying the various manifestations of neural spike signaling as adaptations that optimize a utility function called ecological expected utility