iSTFTNet2: Faster and More Lightweight iSTFT-Based Neural Vocoder Using 1D-2D CNN

The inverse short-time Fourier transform network (iSTFTNet) has garnered attention owing to its fast, lightweight, and high-fidelity speech synthesis. It obtains these characteristics using a fast and lightweight 1D CNN as the backbone and replacing some neural processes with iSTFT. Owing to the difficulty of a 1D CNN to model high-dimensional spectrograms, the frequency dimension is reduced via temporal upsampling. However, this strategy compromises the potential to enhance the speed. Therefore, we propose iSTFTNet2, an improved variant of iSTFTNet with a 1D-2D CNN that employs 1D and 2D CNNs to model temporal and spectrogram structures, respectively. We designed a 2D CNN that performs frequency upsampling after conversion in a few-frequency space. This design facilitates the modeling of high-dimensional spectrograms without compromising the speed. The results demonstrated that iSTFTNet2 made iSTFTNet faster and more lightweight with comparable speech quality. Audio samples are available at https://www.kecl.ntt.co.jp/people/kaneko.takuhiro/projects/istftnet2/.Comment: Accepted to Interspeech 2023. Project page: https://www.kecl.ntt.co.jp/people/kaneko.takuhiro/projects/istftnet2

Electrical Storm in Idiopathic Ventricular Fibrillation Is Associated With Early Repolarization

ObjectivesThis study sought to characterize patients with idiopathic ventricular fibrillation (IVF) who develop electrical storms.BackgroundSome IVF patients develop ventricular fibrillation (VF) storms, but the characteristics of these patients are poorly known.MethodsNinety-one IVF patients (86% male) were selected after the exclusion of structural heart diseases, primary electrical diseases, and coronary spasm. Electrocardiogram features were compared between the patients with and without electrical storms. A VF storm was defined as VF occurring ≥3 times in 24 h and J waves >0.1 mV above the isoelectric line in contiguous leads.ResultsFourteen (15.4%) patients had VF storms occurring out-of-hospital at night or in the early morning. J waves were more closely associated with VF storms compared to patients without VF storms: 92.9% versus 36.4% (p < 0.0001). VF storms were controlled by intravenous isoproterenol, which attenuated the J-wave amplitude. After the subsidence of VF storms, the J waves decreased to the nondiagnostic level during the entire follow-up period. Implantable cardioverter-defibrillator therapy was administered to all patients during follow-up. Quinidine therapy was limited, but the patients on disopyramide (n = 3), bepridil (n = 1), or isoprenaline (n = 1) were free from VF recurrence, while VF recurred in 5 of the 9 patients who were not given antiarrhythmic drugs.ConclusionsThe VF storms in the IVF patients were highly associated with J waves that showed augmentation prior to the VF onset. Isoproterenol was effective in controlling VF and attenuated the J waves, which diminished to below the diagnostic level during follow-up. VF recurred in patients followed up without antiarrhythmic agents

Lovastatin insensitive 1, a novel pentatricopeptide repeat protein, is a potential regulatory factor of isoprenoid biosynthesis in Arabidopsis

Higher plants have two metabolic pathways for isoprenoid biosynthesis: the cytosolic mevalonate (MVA) pathway and the plastidal non-mevalonate (MEP) pathway. Despite the compartmentalization of these two pathways, metabolic flow occurs between them. However, little is known about the mechanisms that regulate the two pathways and the metabolic cross-talk. To identify such regulatory mechanisms, we isolated and characterized the Arabidopsis T-DNA insertion mutant lovastatin insensitive 1 (loi1), which is resistant to lovastatin and clomazone, inhibitors of the MVA and MEP pathways, respectively. The accumulation of the major products of these pathways, i.e. sterols and chlorophyll, was less affected by lovastatin and clomazone, respectively, in loi1 than in the wild type. Furthermore, the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity analysis showed higher activity of HMGR in loi1-1 treated with lovastatin than that in the WT. We consider that the lovastatin-resistant phenotype of loi1-1 was derived from this post-transcriptional up-regulation of HMGR. The LOI1 gene encodes a novel pentatricopeptide repeat (PPR) protein. PPR proteins are thought to regulate the expression of genes encoded in organelle genomes by post-transcriptional regulation in mitochondria or plastids. Our results demonstrate that LOI1 is predicted to localize in mitochondria and has the ability to bind single-stranded nucleic acids. Our investigation revealed that the post-transcriptional regulation of mitochondrial RNA may be involved in isoprenoid biosynthesis in both the MVA and MEP pathways.Peer reviewe

Study on Behavior of Ductile Iron Pipelines with Earthquake Resistant Joint Buried across a Fault

The Tenth International Symposium on Mitigation of Geo-disasters in Asia Matsue Symposium Place: Shimane Civil Center, Matsue Date: 8 October 2012This study is focusing on behavior of ductile iron pipelines with the earthquake resistant joint buried across a fault being used widely for water pipelines in Japan. It is necessary to design a pipeline carefully in case of crossing a fault, because the partially large displacement occurs on the pipelines when a fault moves by an earthquake. However, there are few studies on behavior of ductile iron pipelines. We analyzed the behavior of pipelines near a fault by large displacement analysis method, and we confirmed that the earthquake resistant joint nearest to a fault began to move when a fault began to move, then the joints next in line began to move when the joints movement reached their capacity. In this study, we investigated the behavior of ductile iron pipeline installed into a sand container which moved like a fault for verification of pipeline behavior analysis. As a result, we confirmed that pipeline showed the behavior like the analysis result and we verified the validity

A method for the frequency control in time-resolved two-dimensional gigahertz surface acoustic wave imaging

We describe an extension of the time-resolved two-dimensional gigahertz surface acoustic wave imaging based on the optical pump-probe technique with periodic light source at a fixed repetition frequency. Usually such imaging measurement may generate and detect acoustic waves with their frequencies only at or near the integer multiples of the repetition frequency. Here we propose a method which utilizes the amplitude modulation of the excitation pulse train to modify the generation frequency free from the mentioned limitation, and allows for the first time the discrimination of the resulted upper- and lower-side-band frequency components in the detection. The validity of the method is demonstrated in a simple measurement on an isotropic glass plate covered by a metal thin film to extract the dispersion curves of the surface acoustic waves

Relationship between the Frequency of Microsaccade and Attentional State

It has been shown that the attentional state affects the properties of microsaccade. In this study, we investigated the relationship between the time courses of attentional state and of microsaccade frequency. In one experimental trial, one-digit random number (0–9) was sequentially presented within a preindicated area of the display and one of the numbers (test stimulus) was appeared in a different color. Participants were required to respond the numbers of the test stimulus. We manipulated the size and location of the area within which the stimuli were presented. In the trial, the attentional states before and after the test presentation should be relatively high and low, respectively. Microsaccades, defined as the saccades less than 1 degree of amplitude, were identified using an eye tracker with sampling frequency of 2000 Hz and the change of the frequency was analyzed offline. The result showed that the frequency of microsaccade decreased immediately after the test presentation and then increased relative to that before the test presentation. The size and location of attentional state did not affect the frequency of microsaccade systematically in the present experiments. These results suggest that the frequency of microsaccade could be an indicator of the strength of attention

Study on Behavior of Ductile Iron Pipelines with Earthquake-Resistant Joints Buried across a Fault

This study is focusing on behavior of ductile iron pipelines with earthquake-resistant joints buried across a fault used widely for water pipelines in Japan. It is necessary to design a pipeline carefully in case of crossing a fault, because the partially large displacement occurs on the pipelines when a fault moves by an earthquake. Although there is some research on behavior of steel pipelines which cross a fault, there are few studies of ductile iron pipelines. In this study, we investigated the behavior of pipeline buried across a fault by simulation analysis and verification experiment. As a result, we clarified that the earthquake resistant joint nearest to a fault began to move when a fault began to move, and then the joints in line began to move when the expansion, contraction and deflection angle in the joint nearest to a fault reached its capacity. In addition, we confirmed that we could evaluate the safety of pipeline against the fault movement by deflection angle in each joint. As a result, using colors with large bending performance rather than straight pipe sockets of shortening the pipe length was effective to increase the safety of pipeline near a fault