Scattered Spectra from Inverse Compton Sources Operating at High Laser Fields and High Electron Energies

As Compton x-ray and gamma-ray sources become more prevalent, to understand their performance in a precise way, it becomes important to be able to compute the distribution of scattered photons precisely. For example, codes have been developed at Old Dominion University which were used to understand the performance of the Dresden Compton Source in detail. An ideal model would (i) include the full Compton effect frequency relations between incident and scattered photons, (ii) allow the field strength to be large enough that nonlinear effects are captured, and (iii) allow the effects of electron beam emittance to be introduced and studied. Various authors have considered various pieces of this problem, but until now, no analytical or numerical procedure is known to us that captures these three effects simultaneously. Here we present a model for spectrum calculations which simultaneously cover these aspects. The model is compared to a published full quantum mechanical calculation and found to agree for a case where both full Compton effect and nonlinear field strength are present. We use this model to investigate chirping prescriptions to mitigate ponderomotive broadening

Community-onset Staphylococcus aureus infections presenting to general practices in South-eastern Australia

Community-acquired Staphylococcus aureus infections are a public health concern, yet little is known about infections that do not present to hospital. We identified community-onset S. aureus infections via specimens submitted to a community-based pathology service. Referring doctors confirmed eligibility and described infection site, severity and treatment. Isolates were characterized on antibiotic resistance, PFGE, MLST/SCCmec, and Panton–Valentine leukocidin (PVL), representing 106 community-onset infections; 34 non-multiresistant methicillin-resistant S. aureus (nmMRSA) (resistant to <3 non-β-lactam antibiotics), 15 multiply antibiotic-resistant MRSA (mMRSA) and 57 methicillin-sensitive S. aureus (MSSA). Most (93%) were skin and soft tissue infections. PVL genes were carried by 42% of nmMRSA isolates [95% confidence interval (CI) 26–61] and 15% of MSSA (95% CI 8–28). PVL was associated with infections of the trunk, head or neck (56•4% vs. 24•3%, P = 0•005) in younger patients (23 vs. 52 years, P < 0•001), and with boils or abscesses (OR 8•67, 95% CI 2•9–26•2), suggesting underlying differences in exposure and/or pathogenesis

KH 15D: A Spectroscopic Binary

We present the results of a high-resolution spectroscopic monitoring program of the eclipsing pre-main-sequence star KH 15D that reveal it to be a single-line spectroscopic binary. We find that the best-fit Keplerian model has a period P = 48.38 days, which is nearly identical to the photometric period. Thus, we find the best explanation for the periodic dimming of KH 15D is that the binary motion carries the currently visible star alternately above and below the edge of an obscuring cloud. The data are consistent with the models involving an inclined circumstellar disk, as recently proposed by Winn et al. (2004) and Chiang & Murray-Clay (2004). We show that the mass ratio expected from models of PMS evolution, together with the mass constraints for the visible star, restrict the orbital eccentricity to 0.68 < e < 0.80 and the mass function to 0.125 < Fm < 0.5 Msun.Comment: 8 pages, 4 figures, 3 tables, accepted for publication in September AJ. Discussion of rotational velocity deferred to Hamilton, et al. (2004, in prep). Previously reported vsini value in error; Replaced Table 3 with new Figure 3; Added new Table 2 showing individual radial velocities w.r.t. each reference star; Fixed typo in Figure

Fourteen New Companions from the Keck & Lick Radial Velocity Survey Including Five Brown Dwarf Candidates

We present radial velocities for 14 stars on the California & Carnegie Planet Search target list that reveal new companions. One star, HD 167665, was fit with a definitive Keplerian orbit leading to a minimum mass for the companion of 50.3 Mjup at a separation from its host of ~5.5 AU. Incomplete or limited phase coverage for the remaining 13 stars prevents us from assigning to them unique orbital parameters. Instead, we fit their radial velocities with Keplerian orbits across a grid of fixed values for Msini and period, P, and use the resulting reduced chi-square surface to place constraints on Msini, P, and semimajor axis, a. This technique allowed us to restrict Msini below the brown dwarf -- stellar mass boundary for an additional 4 companions (HD 150554, HD 8765, HD 72780, HD 74014). If the combined 5 companions are confirmed as brown dwarfs, these results would comprise the first major catch of such objects from our survey beyond ~3 AU.Comment: 29 pages, 14 figures, accepted to Ap

A New Planet Around an M Dwarf: Revealing a Correlation Between Exoplanets and Stellar Mass

We report precise Doppler measurements of GJ317 (M3.5V) that reveal the presence of a planet with a minimum mass Msini = 1.2 Mjup in an eccentric, 692.9 day orbit. GJ317 is only the third M dwarf with a Doppler-detected Jovian planet. The residuals to a single-Keplerian fit show evidence of a possible second orbital companion. The inclusion of an additional Jupiter-mass planet (P = 2700 days, Msini = 0.83 Mjup) improves the quality of fit significantly, reducing the rms from 12.5 m/s to 6.32 m/s. A false-alarm test yields a 1.1% probability that the curvature in the residuals of the single-planet fit is due to random fluctuations, lending additional credibility to the two-planet model. However, our data only marginally constrain a two-planet fit and further monitoring is necessary to fully characterize the properties of the second planet. To study the effect of stellar mass on Jovian planet occurrence we combine our samples of M stars, Solar-mass dwarfs and intermediate-mass subgiants. We find a positive correlation between stellar mass and the occurrence rate of Jovian planets within 2.5 AU; the former A-type stars in our sample are nearly 5 times more likely than the M dwarfs to harbor a giant planet. Our analysis shows that the correlation between Jovian planet occurrence and stellar mass remains even after accounting for the effects of stellar metallicity.Comment: ApJ accepted, 27 pages, 6 figures, 3 table

Electrical-end-use data from 23 houses sampled each minute for simulating micro-generation systems

An improved understanding of the consumption patterns, end-uses, and temporal variations of electrical loads in houses is warranted because a significant fraction of a society's total electricity consumption occurs within residential buildings. In general, there is a lack of high-temporal-resolution data describing occupant electrical consumption that are available to researchers in this field. To address this, new measurements were performed and combined with data emanating from an earlier study to provide a database of annual measurements for 23 houses at a 1-min resolution that characterizes whole-house, non-HVAC, air conditioner, and furnace fan electrical draws, as well as the draw patterns of some major appliances. All houses were located in Ottawa, Canada. The non-HVAC measurements of this 23-house sample were shown to be in agreement with published estimates for the housing stock. The furnace fan was found to be the most significant end-use. These high-temporal-resolution data of electrical demands in houses can be used by researchers to increase the fidelity of building performance simulation analyses of different micro-generation technologies in residential buildings

The Prediction Properties of Inverse and Reverse Regression for the Simple Linear Calibration Problem

The calibration of measurement systems is a fundamental but under-studied problem within industrial statistics. The origins of this problem go back to basic chemical analysis based on NIST standards. In today's world these issues extend to mechanical, electrical, and materials engineering. Often, these new scenarios do not provide "gold standards" such as the standard weights provided by NIST. This paper considers the classic "forward regression followed by inverse regression" approach. In this approach the initial experiment treats the "standards" as the regressor and the observed values as the response to calibrate the instrument. The analyst then must invert the resulting regression model in order to use the instrument to make actual measurements in practice. This paper compares this classical approach to "reverse regression," which treats the standards as the response and the observed measurements as the regressor in the calibration experiment. Such an approach is intuitively appealing because it avoids the need for the inverse regression. However, it also violates some of the basic regression assumptions

An Eccentric Hot Jupiter Orbiting the Subgiant HD 185269

We report the detection of a Jupiter-mass planet in a 6.838 day orbit around the 1.28 solar mass subgiant HD 185269. The eccentricity of HD 185269b (e = 0.30) is unusually large compared to other planets within 0.1 AU of their stars. Photometric observations demonstrate that the star is constant to +/-0.0001 mag on the radial velocity period, strengthening our interpretation of a planetary companion. This planet was detected as part of our radial velocity survey of evolved stars located on the subgiant branch of the H-R diagram--also known as the Hertzsprung Gap. These stars, which have masses between 1.2 and 2.5 solar masses, play an important role in the investigation of the frequency of extrasolar planets as a function of stellar mass.Comment: 18 pages, 4 figures, 3 tables, ApJ in press (scheduled for Dec 2006, v652n2

Chemical Analysis of Five Red Giants in the Globular Cluster M10 (NGC 6254)

We have determined Al, $\alpha$, Fe-peak, and neutron capture elemental abundances for five red giant branch (RGB) stars in the Galactic globular cluster M10. Abundances were determined using equivalent width analyses of moderate resolution (R$\sim$15,000) spectra obtained with the Hydra multifiber positioner and bench spectrograph on the WIYN telescope. The data sample the upper RGB from the luminosity level near the horizontal branch to about 0.5 mag below the RGB tip. We find in agreement with previous studies that M10 is moderately metal-poor with [Fe/H]=-1.45 ($\sigma$=0.04). All stars appear enhanced in Al with =+0.33 ($\sigma$=0.19), but no stars have [Al/Fe]$\ga$+0.55. We find the $\alpha$ elements to be enhanced by +0.20 to +0.40 dex and the Fe--peak elements to have [el/Fe]$\sim$0, which are consistent with predictions from type II SN ejecta. Additionally, the cluster appears to be r-process rich with =+0.41.Comment: 16 Pages; 3 Figures; 3 Tables; Accepted for publication in PAS

Enhanced Approaches for Identifying Amadori Products: Application to Peanut Allergens

The dry roasting of peanuts is suggested to influence allergic sensitization as a result of the formation of advanced glycation end products (AGEs) on peanut proteins. Identifying AGEs is technically challenging. The AGEs of a peanut allergen were probed with nano-scale liquid chromatography−electrospray ionization−mass spectrometry (nanoLC−ESI−MS) and tandem mass spectrometry (MS/MS) analyses. Amadori product ions matched to expected peptides and yielded fragments that included a loss of three waters and HCHO. As a result of the paucity of b and y ions in the MS/MS spectrum, standard search algorithms do not perform well. Reactions with isotopically labeled sugars confirmed that the peptides contained Amadori products. An algorithm was developed on the basis of information content (Shannon entropy) and the loss of water and HCHO. Results with test data show that the algorithm finds the correct spectra with high precision, reducing the time needed to manually inspect data. Computational and technical improvements allowed for better identification of the chemical differences between modified and unmodified proteins