Wheat Domestication Accelerated Evolution and Triggered Positive Selection in the β-Xylosidase Enzyme of Mycosphaerella graminicola

Plant cell wall degrading enzymes (PCWDEs) of plant pathogens are receiving increasing interest for their potential to trigger plant defense reactions. In an antagonistic co-evolutionary arms race between host and pathogen, PCWDEs could be under strong selection. Here, we tested the hypothesis that PCWDEs in the fungal wheat pathogen Mycosphaerella graminicola have been positively selected by analyzing ratios of non-synonymous and synonymous nucleotide changes in the genes encoding these enzymes. Analyses of five PCWDEs demonstrated that one (β-xylosidase) has been under strong positive selection and experienced an accelerated rate of evolution. In contrast, PCWDEs in the closest relatives of M. graminicola collected from wild grasses did not show evidence for selection or deviation from a molecular clock. Since the genealogical divergence of M. graminicola from these latter species coincided with the onset of agriculture, we hypothesize that the recent domestication of the host plant and/or agricultural practices triggered positive selection in β-xylosidase and that this enzyme played a key role in the emergence of a host-specialized pathogen

Phylogeography and Demographic History of Babina pleuraden (Anura, Ranidae) in Southwestern China

Factors that determine genetic structure of species in southwestern China remain largely unknown. In this study, sequences of two mitochondrial genes (COI and cyt b) were determined to investigate the phylogeography and demography of Babina pleuraden, a pond frog endemic to southwestern China. A total of 262 individuals from 22 populations across the entire range of the species were collected. Our results indicate that B. pleuraden comprises five well-supported mitochondrial lineages roughly corresponding to five geographical areas. The phylogeographic structure of B. pleuraden has been shaped primarily by the unique regional responses of the Yunnan Plateau to the rapid uplift of the Qinghai-Tibetan Plateau occurred c. 2.5 Mya (B phrase of Qingzang Movement) and climatic oscillation during middle Pleistocene (c. 0.64–0.36 Mya), rather than by the paleo-drainage systems. The present wide distribution of the species has resulted from recent population expansion (c. 0.053–0.025 Mya) from multiple refugia prior to the Last Glacial Maximum, corresponding to the scenario of “refugia within refugia”

Measurement of the Depth of Maximum of Extensive Air Showers above 10^(18) eV

We describe the measurement of the depth of maximum, X_(max), of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 10^(18) eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106_(-21)^(+35)) g/cm^2/decade below 10^(18:24±0.05) eV, and (24±3) g/cm^ 2=decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed

FastIC: A Highly Configurable ASIC for Fast Timing Applications

This work presents the 8-channel FastIC ASIC developed in CMOS 65 nm technology suitable for the readout of positive and negative polarity sensors with intrinsic amplification in High Energy Physics experiments, Positron Emission Tomography and other Time-of-Flight systems. The front-end can be configured to readout each input channel individually or perform analog summation of up to 4 single-ended channels before discrimination in view of extending precise timing to large and segmented areas. The outputs encode the Time-Of-Arrival information and linear Energy measurement in the 5 μA − 25 mA input range with a measured linearity error below 3%, and a power consumption of 12 mW/Ch with default settings. Measurements of Single Photon Time Resolution (SPTR) with a red-light laser source and a Hamamatsu SiPM S13360-3050CS have shown ~140 ps FWHM. Coincidence Time Resolution (CTR) measurements with LSO:Ce:Ca 0.2% measuring 2 × 2 × 5 mm 3 coupled to the same sensor resulted in ~ 104 ps FWHM. The FastIC is compared with the HRFlexToT ASIC under the same conditions, obtaining an SPTR and CTR improvement of 12.8% and 11.4%, respectively