Characterizing Intermittency of 4-Hz Quasi-periodic Oscillation in XTE J1550-564 using Hilbert-Huang Transform

We present the time-frequency analysis results based on the Hilbert-Huang transform (HHT) for the evolution of a 4-Hz low-frequency quasi-periodic oscillation (LFQPO) around the black hole X-ray binary XTE J1550-564. The origin of LFQPOs is still debated. To understand the cause of the peak broadening, we utilized a recently developed time-frequency analysis, HHT, for tracking the evolution of the 4-Hz LFQPO from XTE J1550 564. By adaptively decomposing the ~4-Hz oscillatory component from the light curve and acquiring its instantaneous frequency, the Hilbert spectrum illustrates that the LFQPO is composed of a series of intermittent oscillations appearing occasionally between 3 Hz and 5 Hz. We further characterized this intermittency by computing the confidence limits of the instantaneous amplitudes of the intermittent oscillations, and constructed both the distributions of the QPO's high and low amplitude durations, which are the time intervals with and without significant ~4-Hz oscillations, respectively. The mean high amplitude duration is 1.45 s and 90% of the oscillation segments have lifetimes below 3.1 s. The mean low amplitude duration is 0.42 s and 90% of these segments are shorter than 0.73 s. In addition, these intermittent oscillations exhibit a correlation between the oscillation's rms amplitude and mean count rate. This correlation could be analogous to the linear rms-flux relation found in the 4-Hz LFQPO through Fourier analysis. We conclude that the LFQPO peak in the power spectrum is broadened owing to intermittent oscillations with varying frequencies, which could be explained by using the Lense-Thirring precession model.Comment: 27 pages, 9 figures, accepted for publication in The Astrophysical Journa

Reproductive biology of blue marlin (Makaira nigricans) in the western Pacific Ocean

The reproductive biology of blue marlin (Makaira nigricans) was assessed from 1001 fish (ranging from 121 to 275 cm in eye-to-fork length; EFL) caught by Taiwanese offshore longliners in the western Pacific Ocean from September 2000 to December 2001 and from 843 gonad samples from these fish, The overall sex ratio of the catch was approximately 1:1 dur ing the sampling period, but blue marlin are sexually dimorphic; females are larger than males. Reproductive activity (assessed by histology), a gonadosomatic index, and the distribution of oocyte diameters, indicated that spawning occurred predominantly from May to September. The estimated sizes-at-maturity (EFL50) were 179.76 ±1.01 cm (mean ±standard error) for females and 130 ±1 cm EFL for males. Blue marlin are multiple spawners and oocytes develop asynchronously. The proportion of mature females with ovaries containing postovulatory follicles (0.41) and hydrated oocytes (0.34) indicated that the blue marlin spawned once every 2–3 days on average. Batch fecundity (BF) for 26 females with the most advanced oocytes (≥1000 μm), but without postovulatory follicles, ranged from 2.11 to 13.50 million eggs (6.94 ± 0.54 million eggs). The relationships between batch fecundity (BF, in millions of eggs) and EFL and round weight (RW, kg) were BF = 3.29 × 10 –12 EFL5.31 (r2 = 0.70) and BF = 1.59 × 10–3 RW 1.73 (r2= 0.67), respectively. The parameters estimated in this study are key information for stock assessments of blue marlin in the western Pacific Ocean and will contribute to the conservation and sustainable yield o

What’s Cooking? – Cognitive Training of Executive Function in the Elderly

Executive function involves the efficient and adaptive engagement of the control processes of updating, shifting, and inhibition (Miyake, 2000) to guide behavior toward a goal. It is associated with decrements in many other cognitive functions due to aging (West, 1996; Raz, 2000) with itself particularly vulnerable to the effect of aging (Treitz et al., 2007). Cognitive training in the form of structural experience with executive coordination demands exhibited effective enhancement in the elderly (Hertzog et al., 2008). The current study was thus aimed at the development and evaluation of a training regime for executive function in the elderly. The breakfast cooking task of Craik and Bialystok (2006) was adapted into a multitasking training task in a session (pre-test vs. post-test) by group (control vs. training). In the training condition, participants constantly switched, updated, and planned in order to control the cooking of several foods and concurrently performed a table setting secondary task. Training gains were exhibited on task related measures. Transfer effect was selectively observed on the letter–number sequencing and digit symbol coding test. The cooking training produced short term increase in the efficiency of executive control processing. These effects were interpreted in terms of the process overlap between the training and the transfer tasks

Effects of Convolutional Autoencoder Bottleneck Width on StarGAN-based Singing Technique Conversion

Singing technique conversion (STC) refers to the task of converting from one voice technique to another while leaving the original singer identity, melody, and linguistic components intact. Previous STC studies, as well as singing voice conversion research in general, have utilized convolutional autoencoders (CAEs) for conversion, but how the bottleneck width of the CAE affects the synthesis quality has not been thoroughly evaluated. To this end, we constructed a GAN-based multi-domain STC system which took advantage of the WORLD vocoder representation and the CAE architecture. We varied the bottleneck width of the CAE, and evaluated the conversion results subjectively. The model was trained on a Mandarin dataset which features four singers and four singing techniques: the chest voice, the falsetto, the raspy voice, and the whistle voice. The results show that a wider bottleneck corresponds to better articulation clarity but does not necessarily lead to higher likeness to the target technique. Among the four techniques, we also found that the whistle voice is the easiest target for conversion, while the other three techniques as a source produce more convincing conversion results than the whistle.Comment: The original edition of this paper will be published in the CMMR 2023 Proceedings. This ArXiv publication is a cop

A Retrospective Cohort Study Comparing Stroke Recurrence Rate in Ischemic Stroke Patients With and Without Acupuncture Treatment.

Little was known about the effects of acupuncture on stroke recurrence. The aim of this study is to investigate whether ischemic stroke patients receiving acupuncture treatment have a decreased risk of stroke recurrence. A retrospective cohort study of 30,058 newly diagnosed cases of ischemic stroke in 2000 to 2004 was conducted based on the claims of Taiwan National Health Insurance Research Database. The use of acupuncture treatment and stroke recurrence were identified during the follow-up period from 2000 to 2009. This study compared the risk of stroke recurrence between ischemic stroke cohorts with and without acupuncture treatment by calculating adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of acupuncture associated with stroke recurrence in the Cox proportional hazard model. The stroke recurrence rate per 1000 person-years decreased from 71.4 without to 69.9 with acupuncture treatment (P < 0.001). Acupuncture treatment was associated with reduced risk of stroke recurrence (HR 0.88; 95% CI 0.84-0.91). The acupuncture effect was noted in patients with or without medical treatment for stroke prevention but its impact decreased with aging of stroke patients. Compared with stroke patients without acupuncture treatment and medication therapy, the hazard ratios of stroke recurrence for those had medication therapy only, acupuncture only, and both were 0.42 (95% CI 0.38-0.46), 0.50 (95% CI 0.43-0.57), and 0.39 (95% CI 0.35-0.43), respectively. This study raises the possibility that acupuncture might be effective in lowering stroke recurrence rate even in those on medications for stroke prevention. Results suggest the need of prospective sham-controlled and randomized trials to establish the efficacy of acupuncture in preventing stroke