Quantum state tomography for Kerr parametric oscillators

Kerr parametric oscillators (KPOs) implemented in the circuit QED architecture can operate as qubits. Their applications to quantum annealing and universal quantum computation have been studied intensely. For these applications, the readout of the state of KPOs is of practical importance. We develop a scheme of state tomography for KPOs with reflection measurement. Although it is known that the reflection coefficient depends on the state of the KPO, it is unclear whether tomography of a qubit encoded into a KPO can be performed in a practical way mitigating decoherence during the measurement, and how accurate it is. We show that the reflection coefficient has a one-to-one correspondence with a diagonal element of the density matrix of the qubit when a probe frequency is properly chosen and an additional single-photon-drive is introduced. Thus, our scheme offers a novel way to readout the qubit along an axis of the Bloch sphere, and therefore the reflection measurement and single-qubit gates can constitute state tomography

Willingness to Buy and/or Pay Disparity: Evidence from Fully Autonomous Vehicles

We seek to understand whether environmental concerns, fears of potential accidents, and merits regarding fully autonomous vehicles (FAVs) are motivators of willingness to buy (WTB) and willingness to pay (WTP) of FAVs. To do so, a large-scale survey on FAVs of more than 180,000 respondents was collected in Japan, and structural equation modeling (SEM) validated our findings. Interestingly, this study implicates a form of WTB-WTP disparity: those interested in natural environment conservation would purchase FAVs because they show high interest in overall social problems, and new technologies such as FAVs can resolve such problems, according to previous works. However, our result implies that they would not show high WTP because adopting FAVs does not `directly' contribute to natural environment conservation. Additionally, our results indicate that those who appreciate potential merits would have higher WTB and WTP, while those who fear FAV technology would not purchase FAVs and would have lower WTP. The results bear crucial policy implications for planners by showing the complexity between the factors of FAV WTB and WTP

Insuring Well-being: Psychological Adaptation to Disasters

We examine the impact of life and health insurance spending on subjective well-being. Taking advantage of insurance spending and subjective well-being data on more than 700,000 individuals in Japan, we examine whether insurance spending can buffer declines in subjective well-being due to exposure to mass disaster. We find that insurance spending can buffer drops in subjective well-being by approximately 3-6% among those who experienced the mass disaster of the great East Japan earthquake. Subjective health increases the most, followed by life satisfaction and happiness. On the other hand, insurance spending decreases the subjective well-being of those who did not experience the earthquake by approximately 3-7%. We conclude by monetizing the subjective well-being loss and calculating the extent to which insurance spending can compensate for it. The monetary value of subjective well-being buffered through insurance spending is approximately 33,128 USD for happiness, 33,287 USD for life satisfaction, and 19,597 USD for subjective health for a person in one year. Therefore, we confirm that life/health insurance serves as an ideal option for disaster adaptation. Our findings indicate the importance of considering subjective well-being, which is often neglected when assessing disaster losses

Evaluation of Fatigue Properties under Four-point Bending and Fatigue Crack Propagation in Austenitic Stainless Steel with a Bimodal Harmonic Structure

Austenitic stainless steel (JIS-SUS304L) with a bimodal harmonic structure, which is defined as a coarse-grained structure surrounded by a network of fine grains, was fabricated using powder metallurgy to improve both the strength and ductility. Four-point bending fatigue tests and K-decreasing tests were conducted in air at room temperature under a stress ratio R of 0.1 to investigate fatigue crack propagation in SUS304L. The fatigue limit of this harmonic-structured material was higher than that of the material with a homogeneous coarse-grained structure. This is attributable to the formation of fine grains by mechanical milling and to the suppression of pore formation. In contrast, the threshold stress intensity range, DKth, for the harmonic-structured material was lower than that for the homogeneous coarse-grained material, while the crack growth rates, da/dN, were higher at comparable DK. These results can be attributed to a reduction in the effective threshold stress intensity range, DKeff,th, due to the presence of fine grains in the harmonic structure

Evaluation of fatigue properties under four-point bending and fatigue crack propagation in austenitic stainless steel with a bimodal harmonic structure

Austenitic stainless steel (JIS-SUS304L) with a bimodal harmonic structure, which is defined as a coarse-grained structure surrounded by a network of fine grains, was fabricated using powder metallurgy to improve both the strength and ductility. Four-point bending fatigue tests and K-decreasing tests were conducted in air at room temperature under a stress ratio R of 0.1 to investigate fatigue crack propagation in SUS304L. The fatigue limit of this harmonic-structured material is higher than that of the material with a homogeneous coarse-grained structure. This is attributable to the formation of fine grains by mechanical milling and to the suppression of pore formation. In contrast, the threshold stress intensity range, ?Kth, for the harmonic-structured material is lower than that for the homogeneous coarse-grained material, while the crack growth rates, da/dN, are higher at comparable ?K. These results can be attributed to a reduction in the effective threshold stress intensity range, ?Keff,th, due to the presence of fine grains in the harmonic structure

Taste buds are not derived from neural crest in mouse, chicken, and zebrafish

Our lineage tracing studies using multiple Cre mouse lines showed a concurrent labeling of abundant taste bud cells and the underlying connective tissue with a neural crest (NC) origin, warranting a further examination on the issue of whether there is an NC derivation of taste bud cells. In this study, we mapped NC cell lineages in three different models, Sox10-iCreER(T2)/tdT mouse, GFP(+) neural fold transplantation to GFP(−) chickens, and Sox10-Cre/GFP-RFP zebrafish model. We found that in mice, Sox10-iCreER(T2) specifically labels NC cell lineages with a single dose of tamoxifen at E7.5 and that the labeled cells were widely distributed in the connective tissue of the tongue. No labeled cells were found in taste buds or the surrounding epithelium in the postnatal mice. In the GFP(+)/GFP(−) chicken chimera model, GFP(+) cells migrated extensively to the cranial region of chicken embryos ipsilateral to the surgery side but were absent in taste buds in the base of oral cavity and palate. In zebrafish, Sox10-Cre/GFP-RFP faithfully labeled known NC-derived tissues but did not label taste buds in lower jaw or the barbel. Our data, together with previous findings in axolotl, indicate that taste buds are not derived from NC cells in rodents, birds, amphibians or teleost fish

Taste buds are not derived from neural crest in mouse, chicken, and zebrafish

Our lineage tracing studies using multiple Cre mouse lines showed a concurrent labeling of abundant taste bud cells and the underlying connective tissue with a neural crest (NC) origin, warranting a further examination on the issue of whether there is an NC derivation of taste bud cells. In this study, we mapped NC cell lineages in three different models, Sox10-iCreERT2/tdT mouse, GFP+ neural fold transplantation to GFP− chickens, and Sox10-Cre/GFP-RFP zebrafish model. We found that in mice, Sox10-iCreERT2 specifically labels NC cell lineages with a single dose of tamoxifen at E7.5 and that the labeled cells were widely distributed in the connective tissue of the tongue. No labeled cells were found in taste buds or the surrounding epithelium in the postnatal mice. In the GFP+/GFP− chicken chimera model, GFP+ cells migrated extensively to the cranial region of chicken embryos ipsilateral to the surgery side but were absent in taste buds in the base of oral cavity and palate. In zebrafish, Sox10-Cre/GFP-RFP faithfully labeled known NC-derived tissues but did not label taste buds in lower jaw or the barbel. Our data, together with previous findings in axolotl, indicate that taste buds are not derived from NC cells in rodents, birds, amphibians or teleost fish.</p

Towards HCP-Style macaque connectomes: 24-Channel 3T multi-array coil, MRI sequences and preprocessing

© 2020 The Author(s) Macaque monkeys are an important animal model where invasive investigations can lead to a better understanding of the cortical organization of primates including humans. However, the tools and methods for noninvasive image acquisition (e.g. MRI RF coils and pulse sequence protocols) and image data preprocessing have lagged behind those developed for humans. To resolve the structural and functional characteristics of the smaller macaque brain, high spatial, temporal, and angular resolutions combined with high signal-to-noise ratio are required to ensure good image quality. To address these challenges, we developed a macaque 24-channel receive coil for 3-T MRI with parallel imaging capabilities. This coil enables adaptation of the Human Connectome Project (HCP) image acquisition protocols to the in-vivo macaque brain. In addition, we adapted HCP preprocessing methods to the macaque brain, including spatial minimal preprocessing of structural, functional MRI (fMRI), and diffusion MRI (dMRI). The coil provides the necessary high signal-to-noise ratio and high efficiency in data acquisition, allowing four- and five-fold accelerations for dMRI and fMRI. Automated FreeSurfer segmentation of cortex, reconstruction of cortical surface, removal of artefacts and nuisance signals in fMRI, and distortion correction of dMRI all performed well, and the overall quality of basic neurobiological measures was comparable with those for the HCP. Analyses of functional connectivity in fMRI revealed high sensitivity as compared with those from publicly shared datasets. Tractography-based connectivity estimates correlated with tracer connectivity similarly to that achieved using ex-vivo dMRI. The resulting HCP-style in vivo macaque MRI data show considerable promise for analyzing cortical architecture and functional and structural connectivity using advanced methods that have previously only been available in studies of the human brain