What the Phub?

“Nobody talks to each other anymore.” When my grandfather said this as we sped down the highway, I wondered what to make of it. Is he simply being a negative elderly man, or is there some truth to the statement? Considering that I had been trying to tune out his questions with my headphones the whole drive, I guess I deserved some type of scolding. As his questions were repeated, my mother pointed out to my grandfather that I could not hear him, to which he shook his head and said, “Nobody talks to each other anymore.” Finally, I put aside my sour mood and took off my headphones, answering his questions about college life and my general wellbeing. [excerpt

Effects of turbulence in the atmosphere of Venus on Pioneer Venus radio, phase 2

Two problems related to the effects of turbulence in the atmosphere of Venus on the Pioneer entry probe radio link were studied. In the first problem, the cross correlation between the log amplitude and phase fluctuations of the Pioneer Venus communications link is examined. Data show that for fluctuation frequencies above approximately 1 Hz there is little or no correlation. For frequencies below this region the correlation is weak and the square root of the coherence has a peak value close to 0.65. The second problem consists of interferring turbulence characteristics of the Venus atmosphere from the Mariner 5 phase fluctuations. Data show that with the data processing techniques developed and currently available, the phase error due to oscillator drift, assumed trajectory delay, and spline curve fit exceed the turbulence induced fluctuations. Results show that it is not possible to interfere with the turbulence characteristics from Mariner 5 phase fluctuations

Metal-rich T-dwarfs in the Hyades cluster

We present the results of a search for brown dwarfs (BDs) and very low mass (VLM) stars in the 625 Myr-old, metal-rich ([Fe/H]=0.14) Hyades cluster. We performed a deep (I=23, z=22.5) photometric survey over 16 deg$^2$ around the cluster center. We report the discovery of the first 2 BDs in the Hyades cluster, with a spectral type T1 and T2, respectively. Their optical and near-IR photometry, as well as their proper motion, are consistent with them being cluster members. According to models, their mass is about 50 Jupiter masses at an age of 625 Myr. We also report the discovery of 3 new very low mass stellar members and confirm the membership of 15 others

A deep, wide-field search for substellar members in NGC 2264

We report the first results of our ongoing campaign to discover the first brown dwarfs (BD) in NGC 2264, a young (3 Myr), populous star forming region for which our optical studies have revealed a very high density of potential candidates - 236 in $<$ 1 deg$^2$ - from the substellar limit down to at least $\sim$ 20 M$_{\rm Jup}$ for zero reddening. Candidate BD were first selected using wide field ($I,z$) band imaging with CFH12K, by reference to current theoretical isochrones. Subsequently, 79 (33%) of the $I,z$ sample were found to have near-infrared 2MASS photometry ($JHK_s$ $\pm$ 0.3 mag. or better), yielding dereddened magnitudes and allowing further investigation by comparison with the location of NextGen and DUSTY isochrones in colour-colour and colour-magnitude diagrams involving various combinations of $I$,$J$,$H$ and $K_s$. We discuss the status and potential substellarity of a number of relatively unreddened (A$_{\rm v}$ $<$ 5) likely low-mass members in our sample, but in spite of the depth of our observations in $I,z$, we are as yet unable to unambiguously identify substellar candidates using only 2MASS data. Nevertheless, there are excellent arguments for considering two faint (observed $I$ $\sim$ 18.4 and 21.2) objects as cluster candidates with masses respectively at or rather below the hydrogen burning limit. More current candidates could be proven to be cluster members with masses around 0.1 M$_{\odot}$ {\it via} gravity-sensitive spectroscopy, and deeper near-infrared imaging will surely reveal a hitherto unknown population of young brown dwarfs in this region, accessible to the next generation of deep near-infrared surveys.Comment: 10 pages, 12 figures, accepted by A&

Estimates of heterosis and inbreeding depression for crosses of lowa maize populations

Relative success of maize (Zea mays L.) breeding programs depends on the proper choice of parental germplasm and the recognition and the use of heterotic groups. Our objective was to identify maize populations with exotic germplasm that would be potentially useful germplasm sources in temperate area maize breeding programs. A factorial mating design was used to produce 35 crosses between seven Iowa Stiff Stalk Synthetic and five non-Iowa Stiff Stalk Synthetic populations. The 12 parental populations and their 35 population crosses also were selfed to produce F2 generation. The two sets of genetic materials were evaluated at five Iowa locations for two years. Estimates of general combining ability (GCA) for each parental population and specific combining ability (SCA), heterosis (H) and inbreeding depression (ID) for each population cross were determined for grain yield. The population cross, BS10(FR)C14 by BS29(R)C3, had the greatest significant estimate of SCA (0.55* t ha-1), the greatest grain yield at the F1 (8.30 t ha-1) and F2 (6.71 t ha-1) generations, the lowest estimate of ID (1.59 t ha-1), but the estimate of H (1.90 t ha-1) was similar to the average estimate of H (1.74 t ha-1) for all crosses. BS10(FR)C14 is a selected strain within the Iowa Stiff Stalk Synthetic heterotic group, whereas BS29(R)C3 is an adapted strain of Suwan-1 a tropical cultivar that originated in Thailand. BSSS(R)C14 (0.63* t ha-1) and BS13(S)C9 (0.54* t ha-1), both selected strains of Iowa Stiff Stalk Synthetic, had the greatest estimates of GCA of all parental populations; BS10(FR)C14 had a significantly positive GCA estimate (0.25* t ha-1), which was similar in magnitude to the GCA estimates for BS11(FR)C14, BS29(R)C3, and BSCB1(R)C14 of the non-Iowa Stiff Stalk Synthetic heterotic group. The data provide information on the relative performance of the populations assigned to the respective heterotic groups of the U.S. Corn Belt, and that BS29(R)C3 includes germplasm that could enhance the genetic variation of the non-Iowa Stiff Stalk Synthetic heterotic group

Precise determination of the lattice spacing in full lattice QCD

We compare three different methods to determine the lattice spacing in lattice QCD and give results from calculations on the MILC ensembles of configurations that include the effect of $u$, $d$ and $s$ sea quarks. It is useful, for ensemble to ensemble comparison, to express the results as giving a physical value for $r_1$, a parameter from the heavy quark potential. Combining the three methods gives a value for $r_1$ in the continuum limit of 0.3133(23)(3) fm. Using the MILC values for $r_0/r_1$, this corresponds to a value for the $r_0$ parameter of 0.4661(38) fm. We also discuss how to use the $\eta_s$ for determining the lattice spacing and tuning the $s$-quark mass accurately, by giving values for $m_{\eta_s}$ (0.6858(40) GeV) and $f_{\eta_s}$ (0.1815(10) GeV).Comment: 15 page

Greenhouse Gas Reduction Opportunities for Local Governments: A Quantification and Prioritization Framework

Local governments have steadily increased their initiative to address global climate change, and many present their proposed strategies through climate action plans (CAPs). This study conducts a literature review on current local approaches to greenhouse gas (GHG) reduction strategies by assessing CAPs in California and presents common strategies in the transportation sector along with useful tools. One identified limitation of many CAPs is the omission of quantitative economic cost and emissions data for decision-making on the basis of cost-effectiveness. Therefore, this study proposes a framework for comparing strategies based on their life cycle emissions mitigation potential and costs. The results data can be presented in a marginal abatement cost curve (MACC) to allow for side-by-side comparison of considered strategies. Researchers partnered with Yolo and Unincorporated Los Angeles Counties to analyze 7 strategies in the transportation and energy sectors (five and two, respectively). A MACC was subsequently developed for each county. Applying the life cycle approach revealed strategies that had net cost savings over their life cycle, indicating there are opportunities for reducing emissions and costs. The MACC also revealed that some emissions reduction strategies in fact increased emissions on a life cycle basis. Applying the MACC framework to two case study jurisdictions illustrated both the feasibility and challenges of including quantitative analysis in their decision-making process. An additional barrier to using the MACC framework in the context of CAPs, is the mismatch between a life cycle and annual accounting basis for GHG emissions. Future work could explore more efficient data collection, alternative scopes of emissions for reporting, and environmental justice concerns.View the NCST Project Webpag

Calculation of three-dimensional compressible laminar and turbulent boundary flows. Three-dimensional compressible boundary layers of reacting gases over realistic configurations

A three-dimensional boundary-layer code was developed for particular application to realistic hypersonic aircraft. It is very general and can be applied to a wide variety of boundary-layer flows. Laminar, transitional, and fully turbulent flows of compressible, reacting gases are efficiently calculated by use of the code. A body-oriented orthogonal coordinate system is used for the calculation and the user has complete freedom in specifying the coordinate system within the restrictions that one coordinate must be normal to the surface and the three coordinates must be mutually orthogonal