The anthropogenic CO
accumulating in the ocean is lowering seawater carbonate ion concentration and may reduce calcification rates of marine calcareous organisms. Several proxies based on test ...weights of planktic foraminifera have been used to evaluate the impact of ocean acidification on these organisms. Unfortunately, because of the absence of a method to evaluate the bulk density of a test, the impact of seawater carbonate chemistry on test calcification is still not fully understood. In this study, we measured bulk densities of living Globigerina bulloides (planktic foraminifera) tests with an X-ray micro-computed tomography (XMCT) scanner and compared them with ambient seawater characteristics. Results demonstrated that test bulk densities were controlled by ambient seawater carbonate ion concentrations and that changes of test bulk densities were accompanied by changes in micron to submicron scale porosity of internal ultrastructure. These results suggest that alteration of the bulk density of foraminiferal tests due to acidification of ambient seawater can be directly observed by XMCT scanning. A useful metric of calcification intensity would therefore be physical measurements of test densities with XMCT.
Trends in genetic correlations between longevity, milk yield, and somatic cell score (SCS) during lactation in cows are difficult to trace. In this study, changes in the genetic correlations between ...milk yield, SCS, and cumulative pseudo-survival rate (PSR) during lactation were examined, and the effect of milk yield and SCS information on the reliability of estimated breeding value (EBV) of PSR were determined. Test day milk yield, SCS, and PSR records were obtained for Holstein cows in Japan from 2004 to 2013. A random subset of the data was used for the analysis (825 herds, 205,383 cows). This data set was randomly divided into 5 subsets (162–168 herds, 83,389–95,854 cows), and genetic parameters were estimated in each subset independently. Data were analyzed using multiple-trait random regression animal models including either the residual effect for the whole lactation period (H0), the residual effects for 5 lactation stages (H5), or both of these residual effects (HD). Milk yield heritability increased until 310 to 351 d in milk (DIM) and SCS heritability increased until 330 to 344 DIM. Heritability estimates for PSR increased with DIM from 0.00 to 0.05. The genetic correlation between milk yield and SCS increased negatively to under −0.60 at 455 DIM. The genetic correlation between milk yield and PSR increased until 342 to 355 DIM (0.53–0.57). The genetic correlation between the SCS and PSR was −0.82 to −0.83 at around 180 DIM, and decreased to −0.65 to −0.71 at 455 DIM. The reliability of EBV of PSR for sires with 30 or more recorded daughters was 0.17 to 0.45 when the effects of correlated traits were ignored. The maximum reliability of EBV was observed at 257 (H0) or 322 (HD) DIM. When the correlations of PSR with milk yield and SCS were considered, the reliabilities of PSR estimates increased to 0.31–0.76. The genetic parameter estimates of H5 were the same as those for HD. The rank correlation coefficients of the EBV of PSR between H0 and H5 or HD were greater than 0.9. Additionally, the reliabilities of EBV of PSR of H0 were similar to those for H5 and HD. Therefore, the genetic parameter estimates in H0 were not substantially different from those in H5 and HD. When milk yield and SCS, which were genetically correlated with PSR, were used, the reliability of PSR increased. Estimates of the genetic correlations between PSR and milk yield and between PSR and SCS are useful for management and breeding decisions to extend the herd life of cows.
Time-to-digital converters (TDCs) are used in various fields, including high-energy physics. One advantage of implementing TDCs in field-programmable gate arrays (FPGAs) is the flexibility on the ...modification of the logics, which is useful to cope with the changes in the experimental conditions. Recent FPGAs make it possible to implement TDCs with a time resolution less than 10 ps. On the other hand, various drift chambers require a time resolution of O(0.1) ns, and a simple and easy-to-implement TDC is useful for a robust operation. Herein an eight-channel TDC with a variable bin size down to 0.28 ns is implemented in a Xilinx Kintex-7 FPGA and tested. The TDC is based on a multisampling scheme with quad phase clocks synchronised with an external reference clock. Calibration of the bin size is unnecessary if a stable reference clock is available, which is common in high-energy physics experiments. Depending on the channel, the standard deviation of the differential nonlinearity for a 0.28 ns bin size is 0.13–0.31. The performance has a negligible dependence on the temperature. The power consumption and the potential to extend the number of channels are also discussed.
Though seawater movement is among the important factors that maintain healthy conditions on coral reefs, little is known about the effects of seawater turbulence on the growth of coral primary ...polyps. We cultured aposymbiotic primary polyps of
Acropora digitifera
with and without seawater turbulence and investigated how seawater turbulence affected the physical characteristics of the polyp skeleton. Results showed that seawater turbulence increased the amount of skeletal carbonate and directly influenced calcification of coral hosts. Three-dimensional morphological measurements by X-ray micro-computed tomography revealed that seawater turbulence increased the thickness of the skeletal branches of polyps. Greater thickness of the skeletal branches and increased horizontal growth may significantly enhance survival of primary coral polyps during early life stages before the establishment of algal symbioses.
Longevity is a crucial economic trait in the dairy farming industry. In this study, our objective was to develop a random regression model for genetic evaluation of survival. For the analysis, we ...used test-day records obtained for the first 5 lactations of 380,252 cows from 1,296 herds in Japan between 2001 and 2010; this data set was randomly divided into 7 subsets. The cumulative pseudo-survival rate (PSR) was determined according to whether a cow was alive (1) or absent (0) in her herd on the test day within each lactation group. Each lactation number was treated as an independent trait in a random regression multiple-trait model (MTM) or as a repeated measure in a random regression single-trait repeatability model (STRM). A proportional hazard model (PHM) was also developed as a piecewise-hazards model. The average (± standard deviation) heritability estimates of the PSR at 365 d in milk (DIM) among the 7 data sets in the first (LG1), second (LG2), and third to fifth lactations (LG3) of the MTM were 0.042±0.007, 0.070±0.012, and 0.084±0.007, respectively. The heritability estimate of the STRM was 0.038±0.004. The genetic correlations of PSR between distinct DIM within or between lactation groups were high when the interval between DIM was short. These results indicated that whereas the genetic factors contributing to the PSR between closely associated DIM would be similar even for different lactation numbers, the genetic factors contributing to PSR would differ between distinct lactation periods. The average (± standard deviation) effective heritability estimate based on the relative risk of the PHM among the 7 data sets was 0.068±0.009. The estimated breeding values (EBV) in LG1, LG2, LG3, the STRM, and the PHM were unbiased estimates of the genetic trend. The absolute values of the Spearman’s rank correlation coefficients between the EBV of the relative risk of the PHM and the EBV of PSR at 365 DIM for LG1, LG2, LG3, and the STRM were 0.75, 0.87, 0.91, and 0.93, respectively. These results indicated that the EBV of PSR could predict the genetic contribution to survival. The EBV based on the PSR of the STRM was highly correlated with that of the MTM (0.83–0.96). Furthermore, the calculation load of the STRM was lighter than that of the MTM because the rank of the matrix of the STRM was smaller than that of the MTM. These results indicated that the STRM is an appropriate model for estimating survivability by using random regression models.
Onnagawa shale samples are deformed through the brittle‐ductile transition by increasing the confining pressure. Brittle deformation is characterized by longitudinal splitting of the sample at 3% ...axial strain. A distributed conjugate fracture network characterizes the macroscopic deformation in the ductile field with strain hardening. The onset of transition from brittle to ductile deformation is between 4% and 5% axial strain with a single shear plane defined failure. Deformed samples are scanned in a commercially available X‐ray CT machine to investigate the sensitivity of the fracture network to the choice of threshold voxel value. The primary voxel values of the deformed rock are reversed, and their density distribution is approximated by a normal distribution to extract the voxel value density distribution that fabricated the fracture network (residual). Successive thresholding of the residual histogram shows that the generated fracture network is highly sensitive to the choice of threshold. Post peak thresholding of the residual histogram generates voxel volumes of fractures alone and consecutive thresholding shows that the obtained volume segments of the fractures can interpret possible nucleation, growth, and coalescence within the damaged zone. Results further show similarity to previous 4D tomographic strain localization investigations and damage size distributions by acoustic emission studies. Therefore, despite the postmortem nature of the investigation, the new technique opens possibilities to investigate the possible evolution of fracture properties under elevated confining pressures and in the absence of high energy synchrotron facilities.
Plain Language Summary
With the advancement in technology, the methods of observing rock deformation have developed over the years from the very basic laboratory acoustic emission (AE) tests to more advanced 4D tomographic tests that require synchrotron facilities. However, not everyone has the ability to access these synchrotron facilities. Therefore, in this study we examine the possibility of visualizing fracture formation from a postmortem analysis. To this end, we first deform the rocks under several confining pressures in a conventional triaxial deformation apparatus and scan the deformed samples in a commercial X‐ray CT scanner. Then, we extract the fractures from the whole rock using certain statistical methods. Thusly obtained fracture network is then segmented by thresholding the gray scale. Finally, by this thresholding technique we show that the fracture formation within the damaged zone can be visualized for rocks with preexisting cracks. The obtained results have shown much similarity to previous AE and 4D tomographic test results. Therefore, through this method one can obtain information on rock deformation under the absence of synchrotron facilities or at the instances where rock deformation is difficult to be performed in synchrotron facilities under very high confining pressures.
Key Points
Fracture network extracted by a residual analysis has been calibrated by pycnometer and thickness gauge volume estimations
Segments of the fracture network are visualized by post peak thresholding of the residual histogram
Fracture network is sensitive to the choice of threshold and provide insights to compute possible fracture evolution within the damaged zone
A high-intensity pulsed muon beam is becoming available at the at the Japan Proton Accelerator Research Complex (J-PARC). Many experiments to study fundamental physics using this high-intensity muon ...beam are proposed. An experiment to measure the muon magnetic moment anomaly (g−2) and the muon electric dipole moment (EDM) is one of these experiments and it requires a tracking detector for positrons from muon decay. Fine segmentation is required in a detector to tolerate the high rate of positrons. The time resolution is required to be much better than the muon anomalous spin precession period while a buffer depth of a front-end electronics needs to be much longer than the accelerated muon lifetime. Requirements of this detector also meet requirements of a measurement of the muonium hyperfine structure interval at the J-PARC and another experiment to measure the proton charge radius at Tohoku University. We have developed a single-sided silicon strip sensor with a 190 μm pitch, a front-end electronics with a sampling rate of 200 MHz and a buffer memory depth of 8192, and a data acquisition system based on DAQ-Middleware for the J-PARC muon g−2/EDM experiment. We have fabricated detector modules consisting of this sensor and the front-end electronics. Performance of fabricated detector modules was evaluated at a laboratory and a beam test using the positron beam at Tohoku University. The detector is confirmed to satisfy all requirements of the experiments except for the time walk, which will be solved by the next version of a front-end electronics.
The genetic correlations between milk production traits (daily milk yield, 305-day milk yield, and lactation persistency as the difference between milk yields at days 240 and 60) and daily somatic ...cell score (SCS) within and across first and second lactations in Holstein cows were estimated by using a multiple trait test day (TD) animal model. The data set consisted of 200,095 TD milk and SCS records from 21,238 cows in their first lactations and 143,051 records from 15,281 cows in their second. Data were analyzed by using a two-trait, two-lactation random regression animal model. Genetic correlations between daily SCS and milk production traits were estimated from additive genetic variance component estimates of random regression coefficients. Genetic correlations between daily milk yield in first lactation and daily SCS in both lactations were positive and peaked in early lactation stage. In contrast, the genetic correlations between persistency and daily SCS in both lactations were negative, except in very early lactation stage. These correlations suggested that focusing selection on increasing milk yield early in the first lactation would likely increase SCS, whereas selecting for increased persistency would decrease SCS during both lactations. The genetic correlations between 305-day milk yield and persistency were positive within and across the first and second lactations. These results suggested that selection for lactation persistency could help to increase lactation yield overall in the first and second lactations without increasing SCS.
The invariant mass spectra of e+e- pairs produced in 12 GeV proton-induced nuclear reactions are measured at the KEK Proton Synchrotron. On the low-mass side of the meson peak, a significant ...enhancement over the known hadronic sources has been observed. The mass spectra, including the excess, are well reproduced by a model that takes into account the density dependence of the vector meson mass modification, as theoretically predicted.
Invariant mass spectra of e(+) e(-) pairs have been measured in 12 GeV p + A reactions to detect possible in-medium modification of vector mesons. Copper and carbon targets are used to study the ...nuclear-size dependence of e(+) e(-) invariant mass distributions. A significant excess on the low-mass side of the phi meson peak is observed in the low betagamma(= beta/square root(1-beta(2))) region of phi mesons (betagamma < 1.25) with copper targets. However, in the high betagamma region (betagamma > 1.25), spectral shapes of phi mesons are well described by the Breit-Wigner shape when experimental effects are considered. Thus, in addition to our earlier publications on rho/omega modification, this study has experimentally verified vector meson mass modification at normal nuclear density.
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