Membrane stabilization and desiccation tolerance during seed corn (Zea mays L.) drying

A preconditioning process (treatment at 35°C prior to high-temperature drying) that precludes high-temperature (\u3e45°C) drying injury without major moisture loss was used to study the nature of the desiccation damage in high-moisture seed corn (Zea mays L.). Seed germination was correlated with leachate conductivity (r = -0.79) and sugar leakage (r = -0.80) after different times of preconditioning indicating the involvement of membrane function in the damage. The roles of soluble sugar, membrane phospholipid composition and thermal properties, ABA content, and protein synthesis in the induction of high-temperature desiccation tolerance and membrane stabilization were studied;The percentage composition of sucrose and a larger oligosaccharide, raffinose, increased significantly during preconditioning. The high correlations between the ratio of raffinose to sucrose and warm germination, conductivity, and sugar leakage (r = 0.829, -0.801, and -0.707 for A632, and 0.887, -0.782 and -0.787 for B73, respectively) indicate the added effect of raffinose on the induced protection. These results suggest that soluble sugar compositional relationship rather than absolute content may play an important role in protecting maturing seed from high-temperature drying damage;Among membrane lipids, phosphatidylcholine (PC) accumulated, resulting in an increase in the PC/phosphatidylethanolamine (PE) ratio from 3.6 to 8 within 48 h of preconditioning. The increase in PC/PE ratio coincided with a decrease in both phase transition temperature and enthalpy of transition, which indicate more stable membranes. An increase in fatty acid saturation may result in membranes which more easily cope with high-temperature desiccation;The ABA levels and appearance of desiccation induced proteins indicate that preconditioning and the newly induced proteins may be related to the transfer from desiccation intolerance to desiccation tolerance during post-harvest drying. The relationship of ABA and protein accumulation with high-temperature desiccation tolerance and membrane stabilization will be discussed

The Sloan Digital Sky Survey Reverberation Mapping Project: Improving Lag Detection with an Extended Multiyear Baseline

We investigate the effects of extended multiyear light curves (9 yr photometry and 5 yr spectroscopy) on the detection of time lags between the continuum variability and broad-line response of quasars at z ≳ 1.5, and compare with the results using 4 yr photometry+spectroscopy presented in a companion paper. We demonstrate the benefits of the extended light curves in three cases: (1) lags that are too long to be detected by the shorter-duration data but can be detected with the extended data; (2) lags that are recovered by the extended light curves but are missed in the shorter-duration data due to insufficient light-curve quality; and (3) lags for different broad-line species in the same object. These examples demonstrate the importance of long-term monitoring for reverberation mapping to detect lags for luminous quasars at high redshift, and the expected performance of the final data set from the Sloan Digital Sky Survey Reverberation Mapping project that will have 11 yr photometric and 7 yr spectroscopic baselines

Spintronics with a Weyl point in superconducting nanostructures

We investigate transport in a superconducting nanostructure housing a Weyl point in the spectrum of Andreev bound states. A minimum magnet state is realized in the vicinity of the point. One or more normal-metal leads are tunnel-coupled to the nanostructure. We have shown that this minimum magnetic setup is suitable for realization of all common goals of spintronics: detection of a magnetic state, conversion of electric currents into spin currents, potentially reaching the absolute limit of one spin per charge transferred, detection of spin accumulation in the leads. The peculiarity and possible advantage of the setup is the ability to switch between magnetic and non-magnetic states by tiny changes of the control parameters: superconducting phase differences. We employ this property to demonstrate the feasibility of less common spintronic effects: spin on demand and alternative spin current.Comment: 9 pages, 6 figure

CWITools: A Python3 Data Analysis Pipeline for the Cosmic Web Imager Instruments

The Palomar Cosmic Web Imager (PCWI) and Keck Cosmic Web Imager (KCWI) are integral-field spectrographs on the Hale 5m telescope at Palomar Observatory and the Keck-2 10m telescope at W. M. Keck Observatory, respectively. In recent years, these instruments have been increasingly used to conduct survey work; in particular focused on the circumgalactic and intergalactic media at high redshift. Extracting faint signals from three-dimensional IFU data is a complex task which can become prohibitively difficult for large samples without the proper tools. We present CWITools, a package written in Python3 for the analysis of PCWI and KCWI data. CWITools is designed to provide a pipeline between the output of the standard instrument data reduction pipelines and scientific products such as surface brightness maps, spectra, velocity maps, as well as a wide array of associated models and measurements. While the package is designed specifically for PCWI and KCWI data, the package is open source and can be adapted to accommodate any three-dimensional integral field spectroscopy data. Here, we describe this pipeline, the methodology behind individual steps and provide example applications

The Sloan Digital Sky Survey Reverberation Mapping Project: Initial C IV Lag Results from Four Years of Data

We present reverberation-mapping (RM) lags and black hole mass measurements using the C iv λ1549 broad emission line from a sample of 348 quasars monitored as a part of the Sloan Digital Sky Survey RM Project. Our data span four years of spectroscopic and photometric monitoring for a total baseline of 1300 days, allowing us to measure lags up to ~750 days in the observed frame (this corresponds to a rest-frame lag of ~300 days in a quasar at z = 1.5 and ~190 days at z = 3). We report significant time delays between the continuum and the C iv λ1549 emission line in 48 quasars, with an estimated false-positive detection rate of 10%. Our analysis of marginal lag measurements indicates that there are on the order of ~100 additional lags that should be recoverable by adding more years of data from the program. We use our measurements to calculate black hole masses and fit an updated C iv radius–luminosity relationship. Our results significantly increase the sample of quasars with C iv RM results, with the quasars spanning two orders of magnitude in luminosity toward the high-luminosity end of the C iv radius–luminosity relation. In addition, these quasars are located at some of the highest redshifts (z ≈ 1.4–2.8) of quasars with black hole masses measured with RM. This work constitutes the first large sample of C iv RM measurements in more than a dozen quasars, demonstrating the utility of multiobject RM campaigns

The Sloan Digital Sky Survey Reverberation Mapping Project: Hα and Hβ Reverberation Measurements from First-year Spectroscopy and Photometry

We present reverberation mapping results from the first year of combined spectroscopic and photometric observations of the Sloan Digital Sky Survey Reverberation Mapping Project. We successfully recover reverberation time delays between the g+i band emission and the broad Hβemission line for a total of 44 quasars, and for the broad Hα emission line in 18 quasars. Time delays are computed using the JAVELIN and CREAM software and the traditional interpolated cross-correlation function (ICCF): using well-defined criteria, we report measurements of 32 Hβ and 13 Hα lags with JAVELIN, 42 Hβ and 17 Hα lags with CREAM, and 16 Hβ and eight Hα lags with the ICCF. Lag values are generally consistent among the three methods, though we typically measure smaller uncertainties with JAVELIN and CREAM than with the ICCF, given the more physically motivated light curve interpolation and more robust statistical modeling of the former two methods. The median redshift of our Hβ-detected sample of quasars is 0.53, significantly higher than that of the previous reverberation mapping sample. We find that in most objects, the time delay of the Hαemission is consistent with or slightly longer than that of Hβ. We measure black hole masses using our measured time delays and line widths for these quasars. These black hole mass measurements are mostly consistent with expectations based on the local M_(BH) - σ* relationship, and are also consistent with single-epoch black hole mass measurements. This work increases the current sample size of reverberation-mapped active galaxies by about two-thirds and represents the first large sample of reverberation mapping observations beyond the local universe (z < 0.3)