To differentiate neutron star models by X-ray polarimetry

The nature of pulsar is still unknown because of non-perturbative effects of the fundamental strong interaction, and different models of pulsar inner structures are then suggested, either conventional neutron stars or quark stars. Additionally, a state of quark-cluster matter is conjectured for cold matter at supranuclear density, as a result pulsars could thus be quark-cluster stars. Besides understanding different manifestations, the most important issue is to find an effective way to observationally differentiate those models. X-ray polarimetry would play an important role here. In this letter, we focus on the thermal X-ray polarization of quark/quark-cluster stars. While the thermal X-ray linear polarization percentage is typically higher than ~10% in normal neutron star models, the percentage of quark/quark-cluster stars is almost zero. It could then be an effective method to identify quark/quark-cluster stars by soft X-ray polarimetry. We are therefore expecting to detect thermal X-ray polarization in the coming decades.Comment: 4 pages, 3 figures, submitte

ALDH1 Expression and Vasculogenic Mimicry Are Positively Associated with Poor Prognosis in Patients with Breast Cancer

Background/Aims: This study aimed to explore the prognostic value of aldehyde dehydrogenase 1 (ALDH1) expression and vasculogenic mimicry (VM) in patients with breast cancer. Methods: ALDH1 expression and the presence of VM were examined by immunohistochemistry and CD31/PAS double staining, respectively, using formalin-fixed paraffin-embedded tissues from 202 breast cancer patients. The mean follow-up period ranged from 15 to 115 months. The Kaplan-Meier method was used to plot survival curves. Prognostic values were assessed by multivariate analysis using the Cox regression model. Results: ALDH1 expression was strongly associated with VM (P = 0.005). ALDH1 expression was positively correlated with histological grade (P = 0.011). Both ALDH1 expression and VM were negatively related to the status of the estrogen receptor and progesterone receptor and were statistically increased in triple-negative breast cancer. Patients with ALDH1 expression or VM displayed poorer disease-free survival (DFS) and overall survival (OS) than ALDH1-negative or VM-negative patients, with the worst OS and DFS observed in ALDH1/VM-double-positive patients. ALDH1-positive and VM-positive were independent survival risk factors for DFS and OS. Conclusion: ALDH1 expression and VM are correlated with the survival rate of patients with breast cancer. ALDH1 and VM, either alone or together, are prognostic factors in patients with breast cancer

Ecosystem‐dependent responses of soil carbon storage to phosphorus enrichment

Phosphorus deposition can stimulate both plant carbon inputs and microbial carbon outputs. However, how P enrichment affects soil organic carbon (SOC) storage and the underlying mechanisms remain unclear.We conducted a meta-analysis of 642 SOC observations from 213 field P addition experiments world-wide and explored the regulations of plant inputs, microbial outputs, plant characteristics, and environmental and experimental factors on SOC responses.We found that, globally, P addition stimulated SOC by 4.0% (95% CI: 2.0-6.0%), but the stimulation only occurred in forest and cropland rather than in grassland. Across sites, the response of SOC correlated with that of plant aboveground rather than belowground biomass, suggesting that the change in plant inputs from aboveground was more important than that from belowground in regulating SOC changes due to P addition. Among multiple factors, plant N fixation status and mean annual temperature were the best predictors for SOC responses to P addition, with SOC stimulation being higher in ecosystems dominated by symbiotic nitrogen fixers and ecosystems in high-temperature regions like tropical forests.Our findings highlight the differential and ecosystem-dependent responses of SOC to P enrichment and can contribute to accurate predictions of soil carbon dynamics in a P-enriched world

Detection and Classification of Recessive Weakness in Superbuck Converter Based on WPD-PCA and Probabilistic Neural Network

This paper proposes a detection and classification method of recessive weakness in Superbuck converter through wavelet packet decomposition (WPD) and principal component analysis (PCA) combined with probabilistic neural network (PNN). The Superbuck converter presents excellent performance in many applications and is also faced with today’s demands, such as higher reliability and steadier operation. In this paper, the detection and classification issue to recessive weakness is settled. Firstly, the performance of recessive weakness both in the time and frequency domain are demonstrated to clearly show the actual deterioration of the circuit system. The WPD and Parseval’s theorem are utilized in this paper to feature the extraction of recessive weakness. The energy discrepancy of the fault signals at different wavelet decomposition levels are then chosen as the feature vectors. PCA is also employed to the dimensionality reduction of feature vectors. Then, a probabilistic neural network is applied to automatically detect and classify the recessive weakness from different components on the basis of the extracted features. Finally, the classification accuracy of the proposed classification algorithm is verified and tested with experiments, which present satisfying classification accuracy

Patterns of soil respiration and its temperature sensitivity in grassland ecosystems across China

Soil respiration (Rs), a key process in the terrestrial carbon cycle, is very sensitive to climate change. In this study, we synthesized 54 measurements of annual Rs and 171 estimates of Q10 value (the temperature sensitivity of soil respiration) in grasslands across China. We quantitatively analyzed their spatial patterns and controlling factors in five grassland types, including temperate typical steppe, temperate meadow steppe, temperate desert steppe, alpine grassland, and warm, tropical grassland. Results showed that the mean (±SE) annual Rs was 582.0±57.9 g C mg-2 yrg-1 across Chinese grasslands. Annual Rs significantly differed among grassland types, and was positively correlated with mean annual temperature, mean annual precipitation, soil temperature, soil moisture, soil organic carbon content, and aboveground biomass, but negatively correlated with soil pH (p s among grassland types. Based on the overall data across Chinese grasslands, the Q<10 values ranged from 1.03 to 8.13, with a mean (±SE) of 2.60±0.08. Moreover, the Q< 10 values varied largely within and among grassland types and soil temperature measurement depths. Among grassland types, the highest Q<10 derived by soil temperature at a depth of 5 cm occurred in alpine grasslands. In addition, the seasonal variation of soil respiration in Chinese grasslands generally cannot be explained well by soil temperature using the van't Hoff equation. Overall, our findings suggest that the combined factors of soil temperature and moisture would better predict soil respiration in arid and semi-arid regions, highlight the importance of precipitation in controlling soil respiration in grasslands, and imply that alpine grasslands in China might release more carbon dioxide to the atmosphere under climate warming.</p