Programmable spectral shaping to improve the measurement precision of frequency comb mode-resolved spectral interferometric ranging

Comb-mode resolved spectral domain interferometry (CORE-SDI), which is capable of measuring length of kilometers or more with precision on the order of nanometers, is considered to be a promising technology for next-generation length standards, replacing laser displacement interferometers. In this study, we aim to improve the measurement precision of CORE-SDI using programmable spectral shaping. We report the generation of effectively broad and symmetric light sources through the programmable spectral shaping. The light source used here was generated by the spectrally-broadened electro-optic comb with a repetition rate of 17.5 GHz. Through the programmable spectral shaping, the optical spectrum was flattened within 1 dB, resulting in a square-shaped optical spectrum. As a result, the 3-dB spectral width was extended from 1.15 THz to 6.7 THz. We performed a comparison between the measurement results of various spectrum shapes. We confirmed an improvement in the measurement precision from 69 nm to 6 nm, which was also corroborated by numerical simulations. We believe that this study on enhancing the measurement precision of CORE-SDI through the proposed spectral shaping will make a significant contribution to reducing the measurement uncertainty of future CORE-SDI systems, thereby advancing the development of next-generation length standards.Comment: 22 pages, 10 figure

PREVENTING SUBSTANCE ABUSE AMONG ADOLESCENTS: EVALUATION OF AN INTEGRATED MODEL COMBINING LIFE SKILLS TRANING AND PARENT TRANING

This study examines the effectiveness of an integrated model combining Life Skills Training (LST) for students and Love and Logic Training (LLT) for parents. 310 middle school students and 49 parents were participated in the study. A paired sample t-test was computed to compare pre and post-test scores for each participant. An independent sample t-test was used to determine if statistical differences exist between the treatment and control groups. Alcohol use and resistance to alcohol use among both treatment and control groups were significantly changed after the intervention in a positive way. No significant change in substance use was found in both groups. When it comes to comparison between treatment and control groups, a significant difference was found only in resistance to alcohol use, meaning participants in treatment group showed significantly higher level of resistance to alcohol use than control group after the intervention. Implications of these results for practice and training were discussed

A NUMERICAL STUDY ON THE OPEN WATER PERFORMANCE OF A PROPELLER WITH SINUSOIDAL PITCH MOTION

When a ship operates in waves, the ship moves with 6 degrees-of-freedom, and a propeller at the stern of the ship cannot avoid moving due to the ship motion. Therefore, it is important to analyse the propulsion performance while considering the ship motion in waves for efficient ship operation. The pitch motion of the ship has a dominant effect on the variation of the propeller performance and results in sinusoidal pitch motion of the propeller. In this study, a numerical analysis was done using a KP458 model propeller with a diameter of 10 cm, which was designed for the KLVCC2 body plan. The propeller performance was calculated using computational fluid dynamics (CFD) at several constant tilt angles. Numerical simulations were then conducted with sinusoidal pitch motion in several conditions of varying pitch angle. The variations of the thrust and torque of the propeller in sinusoidal pitch motion were compared with the results obtained in constant tilt angles

PPM1A Controls Diabetic Gene Programming through Directly Dephosphorylating PPAR?? at Ser273

Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a master regulator of adipose tissue biology. In obesity, phosphorylation of PPAR gamma at Ser273 (pSer273) by cyclin-dependent kinase 5 (CDK5)/extracellular signal-regulated kinase (ERK) orchestrates diabetic gene reprogramming via dysregulation of specific gene expression. Although many recent studies have focused on the development of non-classical agonist drugs that inhibit the phosphorylation of PPAR gamma at Ser273, the molecular mechanism of PPAR gamma dephosphorylation at Ser273 is not well characterized. Here, we report that protein phosphatase Mg2+/Mn2+-dependent 1A (PPM1A) is a novel PPAR gamma phosphatase that directly dephosphorylates Ser273 and restores diabetic gene expression which is dysregulated by pSer273. The expression of PPM1A significantly decreases in two models of insulin resistance: diet-induced obese (DIO) mice and db/db mice, in which it negatively correlates with pSer273. Transcriptomic analysis using microarray and genotype-tissue expression (GTEx) data in humans shows positive correlations between PPM1A and most of the genes that are dysregulated by pSer273. These findings suggest that PPM1A dephosphorylates PPAR gamma at Ser273 and represents a potential target for the treatment of obesity-linked metabolic disorders

Two distinct red giant branch populations in the globular cluster NGC 2419 as tracers of a merger event in the Milky Way

Recent spectroscopic observations of the outer halo globular cluster (GC) NGC 2419 show that it is unique among GCs, in terms of chemical abundance patterns, and some suggest that it was originated in the nucleus of a dwarf galaxy. Here we show, from the Subaru narrow-band photometry employing a calcium filter, that the red giant-branch (RGB) of this GC is split into two distinct subpopulations. Comparison with spectroscopy has confirmed that the redder RGB stars in the $hk$[=(Ca$-b)-(b-y)$] index are enhanced in [Ca/H] by $\sim$0.2 dex compared to the bluer RGB stars. Our population model further indicates that the calcium-rich second generation stars are also enhanced in helium abundance by a large amount ($\Delta$Y = 0.19). Our photometry, together with the results for other massive GCs (e.g., $\omega$ Cen, M22, and NGC 1851), suggests that the discrete distribution of RGB stars in the $hk$ index might be a universal characteristic of this growing group of peculiar GCs. The planned narrow-band calcium photometry for the Local Group dwarf galaxies would help to establish an empirical connection between these GCs and the primordial building blocks in the hierarchical merging paradigm of galaxy formation.Comment: 4 pages, 4 figures, 1 table, accepted for the publication in ApJ