Weekly patterns of aerosol in the United States

Data from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network of aerosol samplers and NOAA monitoring sites are examined for weekly cycles. At remote and rural sites, fine particle elemental carbon, crustal elements, and coarse particle mass had pronounced (up to 20%) weekly cycles with minima on Sunday or Monday. Fine particle organic carbon and mass had smaller amplitude cycles, also with Sunday or Monday minima. There was no statistically significant weekly cycle in fine particle sulfate despite a 5 to 15% weekly cycle in power plant SO<sub>2</sub> emissions. Although results for nitrate may be more susceptible to sampling artifacts, nitrate also showed a pronounced weekly cycle with an amplitude similar to elemental carbon. The only species found with a weekend maximum was Pb, probably from general aviation on weekends. Aerosol optical properties at NOAA monitoring sites were consistent with the IMPROVE chemical data, with significant weekly cycles in aerosol light absorption but not light scattering. These results support a large role of diesel emissions in elemental carbon aerosol over the entire United States and suggest that a large fraction of the airborne soil dust is anthropogenic. They also suggest that studies of weekly cycles in temperature, cloudiness, precipitation, or other meteorological variables should look for causes more in light-absorbing particles and possible ice nucleation by dust rather than sulfate or total aerosol. There are also implications for personal exposure and epidemiological studies of aerosol health effects

Arkansas Cotton Variety and Strain Tests 1998

The primary aim of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties in the major cotton growing areas in Arkansas. This information helps seed dealers establish marketing strategies and assists producers in choosing varieties to plant. In this way the annual test facilitates the inclusion of new, improved genetic material into Arkansas cotton production. The 1998 test had 58 entries (including 19 transgenic genotypes and 21 first-year entries), which were evaluated at six sites in eastern Arkansas. The presence of four transgenic and five first-year entries among the top 10 yielding entries suggests that improvement is being accomplished in varietal development. This report also includes the Mississippi County Variety Test (an on-farm evaluation of selected varieties) and the Commercial Strain Test (a two-location evaluation of advanced breeding lines

Effects of disorder in location and size of fence barriers on molecular motion in cell membranes

The effect of disorder in the energetic heights and in the physical locations of fence barriers encountered by transmembrane molecules such as proteins and lipids in their motion in cell membranes is studied theoretically. The investigation takes as its starting point a recent analysis of a periodic system with constant distances between barriers and constant values of barrier heights, and employs effective medium theory to treat the disorder. The calculations make possible, in principle, the extraction of confinement parameters such as mean compartment sizes and mean intercompartmental transition rates from experimentally reported published observations. The analysis should be helpful both as an unusual application of effective medium theory and as an investigation of observed molecular movements in cell membranes.Comment: 9 pages, 5 figure

Laser-induced fluorescence of phosphors for remote cryogenic thermometry

Remote cryogenic temperature measurements can be made by inducing fluorescence in phosphors with temperature-dependent emissions and measuring the emission lifetimes. The thermographic phosphor technique can be used for making precision, noncontact, cryogenic-temperature measurements in electrically hostile environments, such as high dc electric or magnetic fields. The National Aeronautics and Space Administration is interested in using these thermographic phosphors for mapping hot spots on cryogenic tank walls. Europium-doped lanthanum oxysulfide (La2O2S:Eu) and magnesium fluorogermanate doped with manganese (Mg4FGeO6:Mn) are suitable for low-temperature surface thermometry. Several emission lines, excited by a 337-nm ultraviolet laser, provide fluorescence lifetimes having logarithmic dependence with temperature from 4 to above 125 K. A calibration curve for both La2O2S:Eu and Mg4FGeO6:Mn is presented, as well as emission spectra taken at room temperature and 11 K

SCIENCECRAFT

The technological capabilities are now at hand to design an integrated system that combine science instruments, spacecraft and propulsion elements into a single system. The authors have called this a Sciencecraft since it is intended to provide automatic scientific observations of planetary and astrophysical objects. Integration of function allows lower mass and cost and supports a short development cycle. A specific science mission is described in this paper, a flyby of Neptune, Triton and an object in the Kuiper belt. The SCIENCECRAFT system is described. It has electric propulsion and is capable of measuring the surface constituents and morphology of the objects visited and characterizing their atmospheres both in emission and absorption (against the sun). Miniature fields and particles experiments are incorporated that will provide interplanetary information together with details of the magnetic and electric attributes of each object. The SCIENCECRAFT is Delta launched and has a flight time to the Kuiper belt of 7 years. The design is such that the craft functions in a largely autonomous mode to provide low cost mission operations

The effect of branched carbon nanotubes as reinforcing nano-filler in polymer nanocomposites

This work discusses the mechanical and dissipative properties of nanocomposite materials made of a high-performance thermoplastic polymer (polybutylene terephthalate, PBT) integrated with branched carbon nanotubes (bCNTs) as nanofiller. The storage and loss moduli as well as the loss factor/damping ratio of the nanocomposites are experimentally characterized for increasing bCNT weight fractions (wt% bCNT) upon variations of the input cyclic strain amplitude and of the input frequency, respectively. The trends obtained for the nanocomposites mechanical properties indicate improvements both in storage and loss modulus by increasing the bCNT weight fraction from 0.5% to 2%. The striking differences between the damping capacities exhibited by CNT/polymer and bCNT/polymer nanocomposites are discussed to shed light onto the different underlined mechanics of the nanocomposites. Due to the stick–slip relative sliding motion of the polymer chains with respect to the straight CNTs, CNT/PBT nanocomposites are known to exhibit a peak in the damping vs. strain amplitude curves, past which, the damping capacity shows a monotonically increasing trend due to the conjectured sliding of the polymer crystals. On the other hand, we show for the first time that bCNT/PBT nanocomposites do not exhibit a peak in the damping capacity but rather a plateau after an initial drop at low strains. This behavior is attributed to the much reduced mobility of the branched CNTs and the lack of formation of crystalline structures around the bCNTs

Natural Splice Variant of MHC Class I Cytoplasmic Tail Enhances Dendritic Cell-Induced CD8+ T-Cell Responses and Boosts Anti-Tumor Immunity

Dendritic cell (DC)-mediated presentation of MHC class I (MHC-I)/peptide complexes is a crucial first step in the priming of CTL responses, and the cytoplasmic tail of MHC-I plays an important role in modulating this process. Several species express a splice variant of the MHC-I tail that deletes exon 7-encoding amino acids (Δ7), including a conserved serine phosphorylation site. Previously, it has been shown that Δ7 MHC-I molecules demonstrate extended DC surface half-lives, and that mice expressing Δ7-Kb generate significantly augmented CTL responses to viral challenge. Herein, we show that Δ7-Db-expressing DCs stimulated significantly more proliferation and much higher cytokine secretion by melanoma antigen-specific (Pmel-1) T cells. Moreover, in combination with adoptive Pmel-1 T-cell transfer, Δ7-Db DCs were superior to WT-Db DCs at stimulating anti-tumor responses against established B16 melanoma tumors, significantly extending mouse survival. Human DCs engineered to express Δ7-HLA-A*0201 showed similarly enhanced CTL stimulatory capacity. Further studies demonstrated impaired lateral membrane movement and clustering of human Δ7-MHC-I/peptide complexes, resulting in significantly increased bioavailability of MHC-I/peptide complexes for specific CD8+ T cells. Collectively, these data suggest that targeting exon 7-encoded MHC-I cytoplasmic determinants in DC vaccines has the potential to increase CD8+ T-cell stimulatory capacity and substantially improve their clinical efficacy

The origin of mid-infrared emission in massive young stellar objects: multi-baseline VLTI observations of W33A

The circumstellar structure on 100 AU scales of the massive young stellar object W33A is probed using the VLTI and the MIDI instrument. N-band visibilities on 4 baselines are presented which are inconsistent with a spherically symmetric geometry. The visibility spectra and SED are simultaneously compared to 2D axi-symmetric dust radiative transfer models with a geometry including a rotationally flattened envelope and outflow cavities. We assume an O7.5 ZAMS star as the central source, consistent with the observed bolometric luminosity. The observations are also compared to models with and without (dusty and gaseous) accretion disks. A satisfactory model is constructed which reproduces the visibility spectra for each (u,v) point. It fits the silicate absorption, the mid-IR slope, the far-infrared peak, and the (sub)mm of the SED. It produces a 350 micron morphology consistent with observations. The 10 micron emission on 100 AU scales is dominated by the irradiated walls of the cavity sculpted by the outflow. The visibilities rule out the presence of dust disks with total (gas and dust) masses more than 0.01 Msun. However, optically thick accretion disks, interior to the dust sublimation radius, are allowed to accrete at rates equalling the envelope's mass infall rate (up to 10^(-3) Msun/yr) without substantially affecting the visibilities due to the extinction by the extremely massive envelope of W33A.Comment: Accepted for publication in A&

Impact of Added Copper and Chlortetracycline on Growth Performance of Nursery Pigs

A total of 320 nursery pigs (DNA 200 × 400 barrows; initially 16.3 lb BW) were used in a 28-d trial to determine the effect of copper (Cu) and chlortetracycline (CTC), fed alone or in combination, on growth performance of weanling pigs. Pigs were weaned at approximately 21 d of age and fed a common pelleted starter diet (non-medicated) for 7 d after weaning. Pigs were allotted to dietary treatments based on BW and location in a randomized complete block design. Dietary treatments were arranged as a 2 × 2 factorial with main effects of added Cu (0 vs. 200 ppm Cu from copper sulfate) and CTC (0 vs. 440 ppm CTC). Experimental diets were corn-soybean meal-based and were fed in one phase for 28 d in meal form. There were 5 pigs per pen and 8 replications per treatment with each replication consisting of a pair of adjoining pens. The results showed no evidence for an interactive effect of Cu and CTC for any of the performance and economic variables (P \u3e 0.05). From d 0 to 14, added Cu increased (P \u3c 0.05) ADG and ADFI and added CTC improved (P \u3c 0.05) ADG, ADFI, and F/G. From d 14 to 28, the addition of CTC to the diet improved (P \u3c 0.05) ADG and ADFI, but there was no evidence for a Cu effect. For the overall experimental period (d 0 to 28), pigs fed diets with CTC had improved (P \u3c 0.05) ADG, ADFI, and F/G, but there was no evidence for a Cu effect. The inclusion of either Cu or CTC increased (P \u3c 0.05) BW on d 14 and 28. Regarding the economics, added dietary Cu increased (P \u3c 0.05) feed cost per pig and value of gain per pig, but not income over feed cost (IOFC). The addition of CTC to the diet increased (P \u3c 0.05) feed cost per pig, value of gain per pig, and IOFC. In conclusion, the findings of the present study characterize a beneficial effect of feeding Cu for 14 d on growth performance of young pigs (16 to 25 lb) and a positive effect of including CTC in nursery diets. The lack of interactive effects between Cu and CTC suggests that the responses of Cu and CTC on growth performance of nursery pigs are as efficacious when fed alone or in combination

Astroparticle Physics with a Customized Low-Background Broad Energy Germanium Detector

The MAJORANA Collaboration is building the MAJORANA DEMONSTRATOR, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The MAJORANA DEMONSTRATOR will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/c^2 mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the MAJORANA Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.Comment: Submitted to NIMA Proceedings, SORMA XII. 9 pages, 4 figure