Double Paddle Oscillators for the Mechanical Spectroscopy of Ion-Solid Interactions

We demonstrated using a double paddle oscillator to measure subsurface defect formation at room temperatures caused by ion implantation. This sensor has a low amount of noise based because of its high quality factors in certain modes. The double paddle oscillator was bombarded with Ar ions under ultra-high vacuum conditions while it was oscillating. The resultant resonant frequency changes were discussed as a method to determine defect formation inside the bulk substrate

The Rapidly Flaring Afterglow of the Very Bright and Energetic GRB 070125

We report on multi-wavelength observations, ranging from the X-ray to radio wave bands, of the IPN-localized gamma-ray burst GRB 070125. Spectroscopic observations reveal the presence of absorption lines due to O I, Si II, and C IV, implying a likely redshift of z = 1.547. The well-sampled light curves, in particular from 0.5 to 4 days after the burst, suggest a jet break at 3.7 days, corresponding to a jet opening angle of ~7.0 degrees, and implying an intrinsic GRB energy in the 1 - 10,000 keV band of around E = (6.3 - 6.9)x 10^(51) erg (based on the fluences measured by the gamma-ray detectors of the IPN network). GRB 070125 is among the brightest afterglows observed to date. The spectral energy distribution implies a host extinction of Av < 0.9 mag. Two rebrightening episodes are observed, one with excellent time coverage, showing an increase in flux of 56% in ~8000 seconds. The evolution of the afterglow light curve is achromatic at all times. Late-time observations of the afterglow do not show evidence for emission from an underlying host galaxy or supernova. Any host galaxy would be subluminous, consistent with current GRB host-galaxy samples. Evidence for strong Mg II absorption features is not found, which is perhaps surprising in view of the relatively high redshift of this burst and the high likelihood for such features along GRB-selected lines of sight.Comment: 50 pages, 9 figures, 5 tables Accepted to the Astrophysical Journa

MOST detects corotating bright spots on the mid-O type giant {\xi} Persei

We have used the MOST (Microvariability and Oscillations of STars) microsatellite to obtain four weeks of contiguous high-precision broadband visual photometry of the O7.5III(n)((f)) star {\xi} Persei in November 2011. This star is well known from previous work to show prominent DACs (Discrete Absorption Components) on time-scales of about 2 d from UV spectroscopy and NRP (Non Radial Pulsation) with one (l = 3) p-mode oscillation with a period of 3.5 h from optical spectroscopy. Our MOST-orbit (101.4 min) binned photometry fails to reveal any periodic light variations above the 0.1 mmag 3-sigma noise level for periods of hours, while several prominent Fourier peaks emerge at the 1 mmag level in the two-day period range. These longer-period variations are unlikely due to pulsations, including gravity modes. From our simulations based upon a simple spot model, we deduce that we are seeing the photometric modulation of several co-rotating bright spots on the stellar surface. In our model, the starting times (random) and lifetimes (up to several rotations) vary from one spot to another yet all spots rotate at the same period of 4.18 d, the best-estimated rotation period of the star. This is the first convincing reported case of co-rotating bright spots on an O star, with important implications for drivers of the DACs (resulting from CIRs - Corotating Interaction Regions) with possible bright-spot generation via a breakout at the surface of a global magnetic field generated by a subsurface convection zone.Comment: 9 pages, 4 figures, 2 tables, MNRAS in pres

A Meta-Regression Analysis to Evaluate the Effects of Narasin on Grow-Finish Pig Performance

A meta-regression analysis was conducted to evaluate the effects of added narasin in growing-finishing pig diets to predict the influence on average daily gain (ADG), feed efficiency (G:F), and carcass yield. A database was developed containing 21 technical reports, abstracts, and refereed papers from 2012 to 2021 representing 35 observations for growth performance data in studies ranging from 35 to 116 days in length (overall data). In addition, within these 35 observations, individual period data were evaluated (143 observations) using weekly, bi-weekly, or monthly performance intervals (period data). Regression model equations were developed, and predictor variables were assessed with a stepwise manual forward selection procedure. Important variables in predicting the response to added narasin included ADG, average daily feed intake (ADFI), and G:F of the control pigs, feeding duration (shorter or longer than 65 days) and body weight (greater than or less than 230 lb). Using median values from the database for predictor variables, the meta-analysis indicated narasin would be expected to improve ADG between 1.06 to 1.65%, G:F between 0.71 to 1.71%, and carcass yield by 0.31% when fed for longer than 65 days

Exome-wide Rare Variant Analysis Identifies TUBA4A Mutations Associated with Familial ALS

Exome sequencing is an effective strategy for identifying human disease genes. However, this methodology is difficult in late-onset diseases where limited availability of DNA from informative family members prohibits comprehensive segregation analysis. To overcome this limitation, we performed an exome-wide rare variant burden analysis of 363 index cases with familial ALS (FALS). The results revealed an excess of patient variants within TUBA4A, the gene encoding the Tubulin, Alpha 4A protein. Analysis of a further 272 FALS cases and 5,510 internal controls confirmed the overrepresentation as statistically significant and replicable. Functional analyses revealed that TUBA4A mutants destabilize the microtubule network, diminishing its repolymerization capability. These results further emphasize the role of cytoskeletal defects in ALS and demonstrate the power of gene-based rare variant analyses in situations where causal genes cannot be identified through traditional segregation analysis

Functional Characterization of a Novel Xylanase from a Corn Strain of Erwinia chrysanthemi

A β-1,4-xylan hydrolase (xylanase A) produced by Erwinia chrysanthemi D1 isolated from corn was analyzed with respect to its secondary structure and enzymatic function. The pH and temperature optima for the enzyme were found to be pH 6.0 and 35°C, with a secondary structure under those conditions that consists of approximately 10 to 15% α-helices. The enzyme was still active at temperatures higher than 40°C and at pHs of up to 9.0. The loss of enzymatic activity at temperatures above 45°C was accompanied by significant loss of secondary structure. The enzyme was most active on xylan substrates with low ratios of xylose to 4-O-methyl-d-glucuronic acid and appears to require two 4-O-methyl-d-glucuronic acid residues for substrate recognition and/or cleavage of a β-1,4-xylosidic bond. The enzyme hydrolyzed sweetgum xylan, generating products with a 4-O-methyl-glucuronic acid-substituted xylose residue one position from the nonreducing terminus of the oligoxyloside product. No internal cleavages of the xylan backbone between substituted xylose residues were observed, giving the enzyme a unique mode of action in the hydrolysis compared to all other xylanases that have been described. Given the size of the oligoxyloside products generated by the enzyme during depolymerization of xylan substrates, the function of the enzyme may be to render substrate available for other depolymerizing enzymes instead of producing oligoxylosides for cellular metabolism and may serve to produce elicitors during the initiation of the infectious process