272 research outputs found
Break The Spell Of Total Correlation In betaTCVAE
In the absence of artificial labels, the independent and dependent features
in the data are cluttered. How to construct the inductive biases of the model
to flexibly divide and effectively contain features with different complexity
is the main focal point of unsupervised disentangled representation learning.
This paper proposes a new iterative decomposition path of total correlation and
explains the disentangled representation ability of VAE from the perspective of
model capacity allocation. The newly developed objective function combines
latent variable dimensions into joint distribution while relieving the
independence constraints of marginal distributions in combination, leading to
latent variables with a more manipulable prior distribution. The novel model
enables VAE to adjust the parameter capacity to divide dependent and
independent data features flexibly. Experimental results on various datasets
show an interesting relevance between model capacity and the latent variable
grouping size, called the "V"-shaped best ELBO trajectory. Additionally, we
empirically demonstrate that the proposed method obtains better disentangling
performance with reasonable parameter capacity allocation
Heisenberg-limited quantum metrology using 100-photon Fock states
Quantum metrology has emerged as a promising avenue for surpassing the
limitations of classical mechanics in high-precision measurements. However, the
practical implementation of quantum metrology is hindered by the challenges of
manipulating exotic quantum states in large systems. Here, we propose and
demonstrate a hardware-efficient approach to achieve Heisenberg-limited quantum
metrology using large photon-number Fock states. We have developed a
programmable photon number filter that efficiently generates Fock states with
up to 100 photons in a high-quality superconducting microwave cavity. Using
these highly nontrivial states in displacement and phase measurements, we
demonstrate a precision scaling close to the Heisenberg limit and achieve a
maximum metrological gain of up to 14.8 dB. Our hardware-efficient quantum
metrology can be extended to mechanical and optical systems and provides a
practical solution for high metrological gain in bosonic quantum systems,
promising potential applications in radiometry and the search for new
particles.Comment: Main text: 10 pages, 4 figures; Supplement: 16 pages, 9 figures, 1
tabl
Beating the break-even point with a discrete-variable-encoded logical qubit
Quantum error correction (QEC) aims to protect logical qubits from noises by
utilizing the redundancy of a large Hilbert space, where an error, once it
occurs, can be detected and corrected in real time. In most QEC codes, a
logical qubit is encoded in some discrete variables, e.g., photon numbers. Such
encoding schemes make the codewords orthogonal, so that the encoded quantum
information can be unambiguously extracted after processing. Based on such
discrete-variable encodings, repetitive QEC demonstrations have been reported
on various platforms, but there the lifetime of the encoded logical qubit is
still shorter than that of the best available physical qubit in the entire
system, which represents a break-even point that needs to be surpassed for any
QEC code to be of practical use. Here we demonstrate a QEC procedure with a
logical qubit encoded in photon-number states of a microwave cavity,
dispersively coupled to an ancilla superconducting qubit. By applying a pulse
featuring a tailored frequency comb to the ancilla, we can repetitively extract
the error syndrome with high fidelity and perform error correction with
feedback control accordingly, thereby exceeding the break-even point by about
16% lifetime enhancement. Our work illustrates the potential of the
hardware-efficient discrete-variable QEC codes towards a reliable quantum
information processor.Comment: Main text: 8 pages, 3 figures, 1 table; Supplement: 12 pages, 8
figures, 2 table
Fabrication of hierarchical moth-eye structures with durable superhydrophobic property for ultrabroadband visual and mid-infrared applications
Multifunctional antireflective coatings have practical applications as important optical components in many fields, particularly for optical devices and imaging systems. However, a good antireflection application in the visible region is often unsatisfactory for mid-infrared devices, and the difficulty in obtaining multiple capabilities simultaneously is one of the main factors limiting their applications. In this work, hierarchical moth-eye structures with superhydrophobicity were fabricated via inductively coupled plasma reactive ion etching (ICP-RIE) using nanodisk-array masks, which were formed by three-beam laser interference lithography (LIL), for improving the ultra-broadband optical properties. The uniform antireflection efficiency, which was close to 1% reflectivity covering over the visible and mid-infrared wavelength range, was exhibited by the moth-eye structures with high-quality pillar arrays. Additionally, irregular nanostructures were tailored onto the top of the pillars to generate hierarchical moth-eye structures for simultaneously obtaining both the superhydrophobic and anticorrosive properties. The fabricated antireflective structures, with the features of self-cleaning and durability, have the advantage of being for long-term use in harsh environments
Mindfulness-Based Baduanjin Exercise for Depression and Anxiety in People with Physical or Mental Illnesses: A Systematic Review and Meta-Analysis
Objectives: we used a quantitative method to systematically synthesize the emerging literature and critically evaluate the effects of Baduanjin on depression and anxiety in people with physical or mental illnesses. Additionally, we determined if the number of total Baduanjin training sessions is associated with decreased anxiety and depression levels. Methods: both English and Chinese databases were searched for potential studies published between January 1982 and October 2017. The eligible randomized controlled trials were considered for meta-analysis. Effect size (Hedge’s g) was computed for the pooled effects while the random-effect model was set. For moderator analysis; Subgroup meta-analysis for categorical variables and meta-regression for continuous variables were performed. Results: the aggregated result has shown a significant benefit in favour of Baduanjin on anxiety (Hedge’s g = −0.99; CI −1.63 to −0.74) and depression (Hedge’s g = −1.07; CI −1.3 to −0.83). For continuous potential moderators; meta-regression indicated a significant effect for total hours in Baduanjin practice (β = −0.0053; 95% CI −0.009 to −0.0014; p = 0.008). With regard to depression; meta-regression indicated a significant effect for total sessions of Baduanjin practice (β = −0.0023; 95% CI −0.006 to −0.0004; p = 0.028). Conclusions: the encouraging findings indicate the efficacy of Baduanjin exercise in reducing depression and anxiety symptoms in people with physical or mental illnesses. However; the results should be interpreted with caution because of existing methodological limitations (e.g., high risk of bias; Baduanjin combined with other behavioral interventions; and heterogeneity of control groups)
Resveratrol Regulates Mitochondrial Biogenesis and Fission/Fusion to Attenuate Rotenone-Induced Neurotoxicity
It has been confirmed that mitochondrial impairment may underlie both sporadic and familial Parkinson’s disease (PD). Mitochondrial fission/fusion and biogenesis are key processes in regulating mitochondrial homeostasis. Therefore, we explored whether the protective effect of resveratrol in rotenone-induced neurotoxicity was associated with mitochondrial fission/fusion and biogenesis. The results showed that resveratrol could not only promote mitochondrial mass and DNA copy number but also improve mitochondrial homeostasis and neuron function in rats and PC12 cells damaged by rotenone. We also observed effects with alterations in proteins known to regulate mitochondrial fission/fusion and biogenesis in rotenone-induced neurotoxicity. Therefore, our findings suggest that resveratrol may prevent rotenone-induced neurotoxicity through regulating mitochondrial fission/fusion and biogenesis
Potential preventive markers in the intracerebral hemorrhage process are revealed by serum untargeted metabolomics in mice using hypertensive cerebral microbleeds
Hypertensive cerebral microbleeds (HCMB) may be the early stage of hypertensive intracerebral hemorrhage (HICH), which is a serious threat to health due to its high mortality and disability rates. The early clinical symptoms of HCMB may not be significant. Moreover, it is difficult to achieve early diagnosis and intervention for targeted prevention of HICH. Although hypertension (HTN) is a predisposition for HCMB, it remains unclear whether there is any difference between hypertensive patients with or without HCMB. Therefore, we carried out liquid chromatography-mass spectrometry (LC-MS) to analyze early biomarkers for HCMB in mice with hypertension and to lay the foundation for early prevention of HICH in hypertensive patients. In total, 18 C57 male mice were randomly divided into the HCMB (n = 6), HTN (n = 6), and control groups (CON, n = 6). Hematoxylin-eosin and diaminobenzidine staining were used to assess the reliability of the model. The metabolite expression level and sample category stability were tested using the displacement test of orthogonal partial least squares discriminant analysis (OPLS-DA). Significant differences in metabolites were screened out using variable importance in the projection (VIP > 1), which were determined using the OPLS-DA model and the P-value of the t-test (P < 0.05) combined with the nonparametric rank-sum test. With an area under the curve (AUC) > 0.85 and a P-value of 0.05, the receiver operating characteristic curve (ROC) was used to further screen the distinct metabolites of HCMB. Compared with the HTN and CON groups, the HCMB group had significantly higher blood pressure and lower average body weight (P < 0.05). Through untargeted LC-MS analysis, 93 distinct metabolites were identified in the HCMB (P < 0.05, VIP > 1) group. Among these potential biomarkers, six significantly decreased and eight significantly increased differential metabolites were found. Meanwhile, we found that the HCMB group had statistically distinct arginine and purine metabolism pathways (P < 0.05), and citrulline may be the most significant possible biomarker of HCMB (AUC > 0.85, P < 0.05). All of these potential biomarkers may serve as early biomarkers for HICH in hypertension
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