Effects of Photoperiod, Water temperature, and Exogenous Hormones on Spawning and Plasma gonadal Steroid in Starry Flounder, Platichthys stellatus

The sexual maturation and spawning of teleosts are regulated by the external environment and the endocrine system. When the environmental conditions are artificially adjusted at a fish farm, the maturity and spawning of fish can be controlled. In this study, sexual maturation and spawning of the starry flounder, Platichthys stellatus, were artificially induced by adjusting the water temperature and photoperiod at a fish farm to accelerate the species’ natural spawning period. One experimental group acted as a control and was exposed to a natural photoperiod and natural water temperature (NPNT). In contrast, another experimental group was exposed to an adjusted environment consisting of a regulated photoperiod and temperature (RPRT). Daylight time was reduced by 10 minutes every 3 days from 13 hours to a duration of 8 hours. The water temperature was first reduced by 1oC every day, starting at 22oC and ending at 8oC, and then raised to 10oC until the spawning period. Both experimental groups were treated with gonadotropin-releasing hormone analog (GnRHa) pellets to induce ovulation. The results show that when the water temperature and photoperiod were artificially controlled, ovulation could be induced 97 days earlier than the natural spawning. Plasma testosterone levels of RPRT and NPNT tended to increase and then decrease 1–2 months before spawning, and plasma levels of 17α,20β-dihydroxy-4-pregnen-3-one increased 1–2 months before spawning. The concentration of estradiol-17β (E2) in plasma was not associated with spawning

Putative spin liquid in the triangle-based iridate Ba3_3IrTi2_2O9_9

We report on thermodynamic, magnetization, and muon spin relaxation measurements of the strong spin-orbit coupled iridate Ba$_3$IrTi$_2$O$_9$, which constitutes a new frustration motif made up a mixture of edge- and corner-sharing triangles. In spite of strong antiferromagnetic exchange interaction of the order of 100~K, we find no hint for long-range magnetic order down to 23 mK. The magnetic specific heat data unveil the $T$-linear and -squared dependences at low temperatures below 1~K. At the respective temperatures, the zero-field muon spin relaxation features a persistent spin dynamics, indicative of unconventional low-energy excitations. A comparison to the $4d$ isostructural compound Ba$_3$RuTi$_2$O$_9$ suggests that a concerted interplay of compass-like magnetic interactions and frustrated geometry promotes a dynamically fluctuating state in a triangle-based iridate.Comment: Physical Review B accepte

High frequency plant regeneration from mature seedderived callus of Italian ryegrass (Lolium multiflorum) cultivars

In the present study, we have developed a high-frequency plant regeneration system for Italian ryegrass via callus culture using mature seeds as explants. Optimal embryogenic callus induction was found to occur in MS medium containing 5 mg l-1 2,4-D, 0.5 mg l-1 BA, 500 mg l-1 L-proline, 1 g l-1 casein hydrolysate, 30 g l-1 sucrose, 7 mg l-1 AgNO3, 2 mg l-1 CuSO4 and solidified with 3 g l-1 Gelrite. The highest regeneration rate was obtained in MS medium containing 1 mg l-1 2,4-D, 5 mg l-1 BA, 500 mg l-1 L-proline, 1 g l-1 casein hydrolysate, 1 mg l-1 thiamine-HCl, 30 g l-1 sucrose, 7 mg l-1 AgNO3, 2 mg l-1 CuSO4 and solidified with 3 g l-1 Gelrite. By using the most effective treatment determined for each parameter, the highest rates of embryogenic callus formation (48.9%) and regeneration (47.6%) were obtained with the Hwasan 101 cultivar. The overall plant regeneration rates of the examined cultivars ranged from 7.5 to 23.2%. Thus, optimization of regeneration frequency using mature seeds as explant material may offer a simple and efficient protocol for Italian ryegrass that may improve molecular breeding of this species

Improved Correction of Atmospheric Pressure Data Obtained by Smartphones through Machine Learning

A correction method using machine learning aims to improve the conventional linear regression (LR) based method for correction of atmospheric pressure data obtained by smartphones. The method proposed in this study conducts clustering and regression analysis with time domain classification. Data obtained in Gyeonggi-do, one of the most populous provinces in South Korea surrounding Seoul with the size of 10,000 km2, from July 2014 through December 2014, using smartphones were classified with respect to time of day (daytime or nighttime) as well as day of the week (weekday or weekend) and the user’s mobility, prior to the expectation-maximization (EM) clustering. Subsequently, the results were analyzed for comparison by applying machine learning methods such as multilayer perceptron (MLP) and support vector regression (SVR). The results showed a mean absolute error (MAE) 26% lower on average when regression analysis was performed through EM clustering compared to that obtained without EM clustering. For machine learning methods, the MAE for SVR was around 31% lower for LR and about 19% lower for MLP. It is concluded that pressure data from smartphones are as good as the ones from national automatic weather station (AWS) network

Atomic-scale combination of germanium-zinc nanofibers for structural and electrochemical evolution

Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of similar to 50% at 20 C compared to that at 0.2 C-rate) and cycle retention (73% at 3.0 C-rate) with a retaining capacity of 546 mAh g(-1) even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system

Enhanced greenhouse gas emission from exposed sediments along a hydroelectric reservoir during an extreme drought event

An active debate has been underway on the magnitude and duration of carbon (C) emissions from hydroelectric reservoirs, yet little attention has been paid to stochastic C emissions from reservoir sediments during extreme climatic events. A rare opportunity for field measurements of CO2 efflux from a hydroelectric reservoir in Korea during an extreme drought event was used to examine how prolonged droughts can affect microbial organic matter processing and the release of CO2, CH4 and N2O from exposed sediments. Chamber measurements of CO2 efflux along an exposed sediment transect, combined with high-frequency continuous sensor measurements of the partial pressure of CO2 (pCO(2)) in the reservoir surface water, exhibited extraordinary pulses of CO2 from exposed sediments and the turbulent inflowing water in contrast to a small CO2 sink in the main water body of the reservoir and a low efflux of CO2 from the flooded sediment. Significant increases in the production of CO2, CH4 and N2O observed in a laboratory incubation of sediments, together with enhanced activities of phenol oxidase and three hydrolases, indicate a temporary activation of microbial organic matter processing in the drying sediment. The results suggest that drought-triggered pulses of greenhouse gas emission from exposed sediments can offset the C accumulation in reservoir sediments over time scales of years to decades, reversing the trend of declining C emissions from aging reservoirsope

Belle II Technical Design Report

The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector.Comment: Edited by: Z. Dole\v{z}al and S. Un