98 research outputs found

    Silage Making and Silage Additives

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    Silage formation should be considered a self-preservation of a feedstuff by fermentation of some of its nutrients by enzymes present in and/or organisms already present on the feedstuff. The resulting product has been defined as a feedstuff resulting from anaerobic fermentation of moist forage or other feedstuff and by preservation with the formation of acids. Even under ideal conditions of silage formation, nutrient losses will occur during the fermentation process. The discussion which follows will include suggestions and criteria for making high quality silage with minimum loss of nutrients

    ANALYSIS OF A TWO LACTATION TARGET ANIMAL SAFETY STUDY OF SOMIDOBOVE SUSTAINED RELEASE INJECTION IN MULTIPAROUS DAIRY COWS

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    An overview is given of the primary basis for the scientific inference that somidobove sustained release injection is safe for multiparous dairy cows. The process of analysis and interpretation of the voluminous data collected from a target animal safety study which started with 28 cows and lasted two lactations is described. This was a repeated measures study with most of 60 variables being measured or summarized every 28 days resulting in approximately 1500 measurements per cow. The statistical analysis was designed to screen the variables for biological change caused by treatment and consisted of a univariate analysis of variance for repeated measures data both within a lactation and across two lactations. Graphs of least squares means with error bounds and p-value plots of ANOVA p-values helped communicate statistical findings. A cross disciplinary approach interpreted analyses and arrived at inferences

    A Bright Spatially-Coherent Compact X-ray Synchrotron Source

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    Each successive generation of x-ray machines has opened up new frontiers in science, such as the first radiographs and the determination of the structure of DNA. State-of-the-art x-ray sources can now produce coherent high brightness keV x-rays and promise a new revolution in imaging complex systems on nanometre and femtosecond scales. Despite the demand, only a few dedicated synchrotron facilities exist worldwide, partially due the size and cost of conventional (accelerator) technology. Here we demonstrate the use of a recently developed compact laser-plasma accelerator to produce a well-collimated, spatially-coherent, intrinsically ultrafast source of hard x-rays. This method reduces the size of the synchrotron source from the tens of metres to centimetre scale, accelerating and wiggling a high electron charge simultaneously. This leads to a narrow-energy spread electron beam and x-ray source that is >1000 times brighter than previously reported plasma wiggler and thus has the potential to facilitate a myriad of uses across the whole spectrum of light-source applications.Comment: 5 pages, 4 figure

    Heavy ion acceleration in the radiation pressure acceleration and breakout afterburner regimes

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    We present a theoretical study of heavy ion acceleration from ultrathin (20 nm) gold foil irradiated by high-intensity sub-picosecond lasers. Using two-dimensional particle-in-cell simulations, three laser systems are modeled that cover the range between femtosecond and picosecond pulses. By varying the laser pulse duration we observe a transition from radiation pressure acceleration (RPA) to the relativistic induced transparency (RIT) regime for heavy ions akin to light ions. The underlying physics of beam formation and acceleration is similar for light and heavy ions, however, nuances of the acceleration process make the heavy ions more challenging. A more detailed study involving variation of peak laser intensity I-0 and pulse duration tau(FWHM) revealed that the transition point from RPA to RIT regime depends on the peak laser intensity on target and occurs for pulse duration tau(RPA -> RIT)(FWHM) [fs] congruent to 210/root I-0 [W cm (2)]/10(21) The most abundant gold ion and charge-to-mass ratio are Au51+ and q/M approximate to 1/4, respectively, half that of light ions. For ultrathin foils, on the order of one skin depth, we established a linear scaling of the maximum energy per nucleon (E/M)(max) with (q/M)(max), which is more favorable than the quadratic one found previously. The numerical simulations predict heavy ion beams with very attractive properties for applications: high directionality (10(11) ions sr(-1)) and energy (>20 MeV/nucleon) from laser systems delivering >20 J of energy on target

    Generation of heavy ion beams using femtosecond laser pulses in the target normal sheath acceleration and radiation pressure acceleration regimes

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    Theoretical study of heavy ion acceleration from sub-micron gold foils irradiated by a short pulse laser is presented. Using two dimensional particle-in-cell simulations, the time history of the laser pulse is examined in order to get insight into the laser energy deposition and ion acceleration process. For laser pulses with intensity 3 x 10(21) W/cm(2), duration 32 fs, focal spot size 5 mu m, and energy 27 J, the calculated reflection, transmission, and coupling coefficients from a 20 nm foil are 80%, 5%, and 15%, respectively. The conversion efficiency into gold ions is 8%. Two highly collimated counter-propagating ion beams have been identified. The forward accelerated gold ions have average and maximum charge-to-mass ratio of 0.25 and 0.3, respectively, maximum normalized energy 25MeV/nucleon, and flux 2 x 10(11) ions/sr. An analytical model was used to determine a range of foil thicknesses suitable for acceleration of gold ions in the radiation pressure acceleration regime and the onset of the target normal sheath acceleration regime. The numerical simulations and analytical model point to at least four technical challenges hindering the heavy ion acceleration: low charge-to-mass ratio, limited number of ions amenable to acceleration, delayed acceleration, and high reflectivity of the plasma. Finally, a regime suitable for heavy ion acceleration has been identified in an alternative approach by analyzing the energy absorption and distribution among participating species and scaling of conversion efficiency, maximum energy, and flux with laser intensity. Published by AIP Publishing

    Association of CpG island methylator phenotype and EREG/AREG methylation and expression in colorectal cancer

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    BACKGROUND: High EREG and AREG expression, and left-sided primary tumours are associated with superior efficacy of anti-epidermal growth factor receptor (EGFR) therapy in metastatic colorectal cancer (CRC), but a unifying explanation of these findings is lacking. METHODS: RNA-seq, gene expression arrays, and DNA methylation profiling were completed on 179 CRC tumours. Results were validated using independent The Cancer Genome Atlas data sets. An independent cohort of 198 KRAS wild-type metastatic CRC tumours was tested for CpG island methylator phenotype (CIMP) status, and progression-free survival (PFS) with the first anti-EGFR regimen was retrospectively determined. RESULTS: EREG and AREG expression was highly inversely correlated with methylation and was inversely associated with right-sided primary tumour, BRAF mutation, and CIMP-high status. Treatment of CRC cell lines with hypomethylating agents decreased methylation and increased expression of EREG. Inferior PFS with anti-EGFR therapy was associated with CIMP-high status, BRAF mutation, NRAS mutation, and right-sided primary tumour on univariate analysis. Among known BRAF/NRAS wild-type tumours, inferior PFS remained associated with CIMP-high status (median PFS 5.6 vs 9.0 mo, P=0.023). CONCLUSIONS: EREG and AREG are strongly regulated by methylation, and their expression is associated with CIMP status and primary tumour site, which may explain the association of primary tumour site and EREG/AREG expression with anti-EGFR therapy efficacy

    Synchrotron x-ray radiation from laser wakefield accelerated electron beams in a plasma channel

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    Synchrotron x-ray radiation from laser wakefield accelerated electron beams was characterized at the HERCULES facility of the University of Michigan. A mono-energetic electron beam with energy up to 400 MeV was observed in the interaction of an ultra-short laser pulse with a super-sonic gas jet target. The experiments were performed at a peak intensity of 5×1019 W/cm2 by using an adaptive optic. The accelerated electron beam undergoes a so called "betatron" oscillation in an ion channel, where plasma electrons have been expelled by the laser ponderomotive force, and, therefore, emits synchrotron radiation. We observe broad synchrotron x-ray radiation extending up to 30 keV. We find that this radiation is emitted in a beam with a divergence angle as small as 12×4 mrad2 and can have a source size smaller than 3 microns and a peak brightness of 1022 photons/mm2/mrad2/second/0.1% bandwidth, which is comparable to currently existing 3rd generation conventional light sources. This opens up the possibility of using laser-produced "betatron" sources for many applications that currently require conventional synchrotron sources.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85402/1/jpconf10_244_042026.pd

    Proton stopping measurements at low velocity in warm dense carbon

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    : Ion stopping in warm dense matter is a process of fundamental importance for the understanding of the properties of dense plasmas, the realization and the interpretation of experiments involving ion-beam-heated warm dense matter samples, and for inertial confinement fusion research. The theoretical description of the ion stopping power in warm dense matter is difficult notably due to electron coupling and degeneracy, and measurements are still largely missing. In particular, the low-velocity stopping range, that features the largest modelling uncertainties, remains virtually unexplored. Here, we report proton energy-loss measurements in warm dense plasma at unprecedented low projectile velocities. Our energy-loss data, combined with a precise target characterization based on plasma-emission measurements using two independent spectroscopy diagnostics, demonstrate a significant deviation of the stopping power from classical models in this regime. In particular, we show that our results are in closest agreement with recent first-principles simulations based on time-dependent density functional theory
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