1,591 research outputs found
Seed germination of three dominant Artemisia species in loess hilly region: alternating temperature, osmotic potential, and light effects
Non-Peer ReviewedIn this study, we evaluated the effects of alternating temperature, osmotic potential and light in the achene germination of three dominant Artemisia species (A. scoparia, A. gmelinii Web. and A. giraldii Pamp.) on arable old land after being abandoned in loess hilly region of Northern Shaanxi, in order to provide information about germination requirements which could be use for conservation studies. Results showed that A. scoparia had wider alternating temperature extremes than two other species and A. giraldii Pamp. and A. gmelinii Web. had lower optimum alternating temperature (25 oC/20 oC) than A. scoparia (30 oC/25 oC). Osmotic potential affected germination of all species significantly, but A. scoparia had better germination results than others in every treatment. In light treatments, although A. giraldii Pamp. and A. gmelinii Web. had lower germination proportion in white light, they had bigger germination proportion in darkness than A. scoparia
Investigating properties of heavy and superheavy atomic systems with configurations
We have investigated energies and spectroscopic properties such as lifetimes,
factors, and hyperfine structure constants of the neutral atoms P through
Mc belonging to Group-15, singly ionized atoms S through Lv of Group-16
and doubly ionized atoms Cl through Ts of Group-17 of the
periodic table. These elements have configurations with , which
are highly open-shell and expected to exhibit strong electron correlation
effects. We have used four-component Dirac-Coulomb Hamiltonian along with Gaunt
term and a relativistic effective core potential through the relativistic
multi-reference configuration interaction method to perform the calculations
with sufficient accuracy and compare the results with the available literature
data. These comparisons suggest that our predicted values, for which
experimental data are not available, are reliable enough to be useful for
future applications.Comment: 19 pages,12 table
Scaling Behavior of Quasi-One-Dimensional Vortex Avalanches in Superconducting Films
Scaling behaviour of dynamically driven vortex avalanches in superconducting
YBaCuO films deposited on tilted crystalline
substrates has been observed using quantitative magneto-optical imaging. Two
films with different tilt angles are characterized by the probability
distributions of avalanche size in terms of the number of moving vortices. It
is found in both samples that these distributions follow power-laws over up to
three decades, and have exponents ranging between 1.0 and 1.4. The
distributions also show clear finite-size scaling, when the system size is
defined by the depth of the flux penetration front -- a signature of
self-organized criticality. A scaling relation between the avalanche size
exponent and the fractal dimension, previously derived theoretically from
conservation of the number of magnetic vortices in the stationary state and
shown in numerical simulations, is here shown to be satisfied also
experimentally.Comment: 7 pages, 5 figure
Arctic troposphere warming Driven by external radiative forcing and modulated by the Pacific and Atlantic
During the past decades, the Arctic has experienced significant tropospheric warming, with varying decadal warming rates. However, the relative contributions from potential drivers and modulators of the warming are yet to be further quantified. Here, we utilize a unique set of multi-model large-ensemble atmospheric simulations to isolate the respective contributions from the combined external radiative forcing (ERF-AL), interdecadal Pacific variability (IPV), Atlantic multidecadal variability (AMV), and Arctic sea-ice concentration changes (ASIC) to the warming during 1979â2013. In this study, the ERF-AL impacts are the ERF impacts directly on the atmosphere and land surface, excluding the indirect effects through SST and SIC feedback. The ERF-AL is the primary driver of the AprilâSeptember tropospheric warming during 1979â2013, and its warming effects vary at decadal time scales. The IPV and AMV intensify the warming during their transitioning periods to positive phases and dampen the warming during their transitioning periods to negative phases. The IPV impacts are prominent in winter and spring and are stronger than AMV impacts on 1979â2013 temperature trends. The warming impacts of ASIC are generally restricted to below 700 hPa and are strongest in autumn and winter. The combined effects of these factors reproduce the observed accelerated and step-down Arctic warming in different decades, but the intensities of the reproduced decadal variations are generally weaker than in the observed. © 2022. The Authors
A Fuzzy-Interval Dynamic Optimization Model for Regional Water Resources Allocation under Uncertainty
In this study, a fuzzy-interval dynamic programming (FIDP) model is proposed for regional water management under uncertainty by combining fuzzy-interval linear programming (FILP) and dynamic programming (DP). This model can not only tackle uncertainties presented as intervals, but also consider the dynamic characteristics in the allocation process for water resources. Meanwhile, the overall satisfaction from users is considered in the objective function to solve the conflict caused by uneven distribution of resources. The FIDP model is then applied to the case study in terms of water resources allocation under uncertainty and dynamics for the City of Handan in Hebei Province, China. The obtained solutions can provide detailed allocation schemes and water shortage rates at different stages. The calculated comprehensive benefits of economy, water usersâ satisfaction and pollutant discharge (i.e., COD) are [2264.72, 2989.33] Ă 108 yuan, [87.50, 96.50] % and [1.23, 1.65] Ă 108 kg respectively with a plausibility degree (i.e., λ±opt) ranging within [0.985, 0.993]. Moreover, the benefit from FIDP model under consideration of dynamic features is more specific and accurate than that of FILP model, whilst the water shortage rate from FIDP is [5.10, 9.10] % lower than that of FILP model.This research was supported by Nation Natural Science Foundation of China (61873084), and Natural Science Foundation of Hebei, in China (D2019402235)
Adaptive polarization-difference transient imaging for depth estimation in scattering media
Introducing polarization into transient imaging improves depth estimation in participating media, by discriminating reflective from scattered light transport and calculating depth from the former component only. Previous works have leveraged this approach under the assumption of uniform polarization properties. However, the orientation and intensity of polarization inside scattering media is nonuniform, both in the spatial and temporal domains. As a result of this simplifying assumption, the accuracy of the estimated depth worsens significantly as the optical thickness of the medium increases. In this Letter, we introduce a novel adaptive polarization-difference method for transient imaging, taking into account the nonuniform nature of polarization in scattering media. Our results demonstrate a superior performance for impulse-based transient imaging over previous unpolarized or uniform approaches
Dietary Vitamin A Impacts Refractory Telogen.
Hair follicles cycle through periods of growth (anagen), regression (catagen), rest (telogen), and release (exogen). Telogen is further divided into refractory and competent telogen based on expression of bone morphogenetic protein 4 (BMP4) and wingless-related MMTV integration site 7A (WNT7A). During refractory telogen hair follicle stem cells (HFSC) are inhibited. Retinoic acid synthesis proteins localized to the hair follicle and this localization pattern changed throughout the hair cycle. In addition, excess retinyl esters arrested hair follicles in telogen. The purpose of this study was to further define these hair cycle changes. BMP4 and WNT7A expression was also used to distinguish refractory from competent telogen in C57BL/6J mice fed different levels of retinyl esters from two previous studies. These two studies produced opposite results; and differed in the amount of retinyl esters the dams consumed and the age of the mice when the different diet began. There were a greater percentage of hair follicles in refractory telogen both when mice were bred on an unpurified diet containing copious levels of retinyl esters (study 1) and consumed excess levels of retinyl esters starting at 12 weeks of age, as well as when mice were bred on a purified diet containing adequate levels of retinyl esters (study 2) and remained on this diet at 6 weeks of age. WNT7A expression was consistent with these results. Next, the localization of vitamin A metabolism proteins in the two stages of telogen was examined. Keratin 6 (KRT6) and cellular retinoic acid binding protein 2 (CRABP2) localized almost exclusively to refractory telogen hair follicles in study 1. However, KRT6 and CRABP2 localized to both competent and refractory telogen hair follicles in mice fed adequate and high levels of retinyl esters in study 2. In mice bred and fed an unpurified diet retinol dehydrogenase SDR16C5, retinal dehydrogenase 2 (ALDH1A2), and cytochrome p450 26B1 (CYP26B1), enzymes and proteins involved in RA metabolism, localized to BMP4 positive refractory telogen hair follicles. This suggests that vitamin A may contribute to the inhibition of HFSC during refractory telogen in a dose dependent manner
Analysis of Bilateral Trade Flow and Machine Learning Algorithms for GDP Forecasting
The terms imports and exports describe goods and services traded between countries. Countries import goods they cannot produce domestically or can obtain at a lower cost from another country. According to the World Trade Organization (WTO) reports, the U.S. is the worldâs largest importer based on capital investment, followed by the E.U., China, Germany, and Japan. For exports, China leads the world with an official trade amount of $1.904 trillion in 2013. E.U. ranks second, followed by U.S., Germany, and Japan. Trade in goods and services is defined as a change in ownership of material resources and services between economies. Trade indicators include the sale of goods and services as well as barter transactions or goods exchanged and are measured in million USD, the percentage of GDP for net trade, and the annual export and import growth. This study analyzes imports and exports of all countries for the 1960-2017 period and evaluates the correlations in trade statistics to predict future imports and exports. Since the GDP for any country depends mainly on trade, this study examines trade data and compares various machine learning algorithms to forecast a countryâs GDP
- âŠ