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Seed reserves play vital roles in seed germination and seedling growth and their variation may be related to various environment factors, plant traits and phylogenetic history. Here, the evolutionary correlation associated with seed mass and altitude and carbon (C), nitrogen (N) and phosphorus (P) allocation of seeds among 253 alpine herbaceous plants was tested. In this study, phylogeny had strong limitations on nutrient allocation of seeds across species, and species from younger phylogenetic groups tended to have higher N and P contents, which might be considered as the evolutionary selection of seed plants. Higher seed N and P content would help seedlings to gain more survival chance and stronger competitive capacity, and their progeny would be more likely to be preserved. When phylogeny was considered, altitude only had a significant positive effect on P content, but the negative effects on seed mass were all expressed. The independent effects of altitude and seed mass suggest that the nutrient allocation of seeds might be affected by both environment and plant traits. In addition, altitude and seed mass displayed partial overlapping effects on nutrient allocation of seeds. The negative effects of seed mass were affected slightly by altitude, whereas altitude only had a significant positive effect on P content when seed mass was controlled. Above all, seed P content showed obvious and general correlations with seed mass, altitude and age of clade, which indicated that higher seed P content might be an adaptive selection of species associated with growth and survival of progeny.
Health system reform is considered a tough issue worldwide. Great efforts have been made toward health system building and strengthening. However, it is still unclear which health system is appropriate for different countries. This study aimed to systematically compare the characteristics of the establishment periods between eighty-eight counties of National Health Service (NHS) and Social Health Insurance (SHI).
Forty-eight NHS countries and forty SHI countries with data availability were selected. The establishment years of current health systems and other eighteen indicators in economics, society, population and health during establishment periods were collected. Comparison between NHS and SHI was conducted by descriptive analysis of every indicator.
Most NHS countries were established during the cold war, while SHI had been set up since the cold war ended. The median of gross domestic product (GDP) per capita, urbanization rate and aging rate of SHI were USD 1535 in current dollars, 58.2 percent and 9.8 percent, respectively; compared with USD 1387, 41.2 percent and 4.7 percent, respectively of NHS. NHS countries had a smaller total population, lower mortality rate and elderly dependency ratio, while the birth rate and children's dependency ratio were higher. SHI countries showed a higher life expectancy and lower mortality rate in infants and children. NHS countries spent less in total health expenditure and a lower proportion of GDP. The median health expenditure per capita of SHI and NHS were USD 188 and USD 131 in current dollars, respectively. There was little difference among maternal mortality rates, and public and private health expenditure proportions.
NHS and SHI countries had different characteristics during the health system establishment periods. NHS was established earlier than SHI overall, so that SHI revealed higher levels in economic and social development. Health outcomes of NHS countries were slightly lower than SHI ones, while health expenditure was more in SHI countries. Specific social, economic, demographic and health conditions should be considered when countries are building their own health systems.
In this paper, we focus on studying the high energy emission of GRB 160625B. The lightcurve of prompt emission is composed of three episodes: short-soft precursor, hard main burst, and possible long extended emission. The spectra of first and third episode can be fitted by a multi-color blackbody and cutoff power-law model, respectively. However, the spectrum of second episode was contributed by both multi-color blackbody and cutoff power-law. One can estimate the Lorenz factor of jet of first two episodes by invoking photosphere model as Γ0 ~ 175 and 1694, respectively. It suggests that the ejecta of this case evolved from photosphere dominated initially to internal shock later. On the other hand, the optical emission is very bright during the second episode, which is likely a prompt optical emission. Finally, a more shallower normal decay segment appeared, which is consistent with standard external shock model.
The Lorentz factor (Γ) is an important parameter related to the relativistic jet physics. We study the evolution patterns of Γ within gamma-ray burst (GRB) and active galactic nuclear jets for individual GRB 090168, GRB 140508A, and 3C 454.3. By estimating the Γ values for well-separated pulses in GRBs 090618 and 140508A with an empirical relation derived from typical GRBs, we find that the Γ evolution pattern in the two GRBs are different. The increasing-to-coasting evolution pattern of Γ in GRB 090618 likely indicates that the GRB fireball is still being accelerated in the prompt phase. The clear decrease evolution pattern of Γ in GRB 140508A suggests the deceleration of the fireball components. By deriving the Γ value through fitting their spectral energy distribution in different flares of 3C 454.3, a pattern of Γ-tracking-γ-ray flux is clearly found, likely indicating that the observed gamma-ray flares are being due to the Doppler boosting effect to the jet emission.
High energy photon radiations of gamma-ray bursts (GRBs) and active galactic nuclei (AGNs) are dominated by their jet radiations. It was suggested that relativistic jets powered by different mass-scale black holes may share the same physical laws. A tight relation among the peak luminosity, the peak photon energy in the νfν spectrum, and the initial Lorentz factor is found for GRBs. With samples of GeV-TeV BL Lacs, FSRQs, and NLS1 galaxies, we show that these sources do not follow this relation. This may be attributed to the jet geometry and continuous/episodic jet as well as radiation physics for different kinds of sources.
Two transmission curved crystal spectrometers are designed to measure the hard x-ray emission in the laser fusion experiment of Compton radiography of implosion target on ShenGuang-III laser facility in China. Cylindrically curved
-quartz (10–11) crystals with curvature radii of 150 and 300 mm are used to cover spectral ranges of 10–56 and 17–100 keV, respectively. The distance between the crystal and the x-ray source can be changed over a broad distance from 200 to 1500 mm. The optical design, including the integral reflectivity of the curved crystal, the sensitivity, and the spectral resolution of the spectrometers, is discussed. We also provide mechanic design details and experimental results using a Mo anode x-ray source. High-quality spectra were obtained. We confirmed that the spectral resolution can be improved by increasing the working distance, which is the distance between the recording medium and the Rowland circle.
Microstructural and property evolution of 1050 commercial pure aluminum subjected to high-strain-rate deformation (1.2–2.3 × 103 s−1) by split Hopkinson pressure bar (SHPB) and subsequent annealing treatment were investigated. The as-deformed and their annealed samples at 373–523 K were characterized by transmission electron microscopy (TEM) and microhardness tests. TEM observations reveal that the as-deformed sample is mainly composed of a lamellar structure, whose transverse/longitudinal average subgrain/cell sizes are 293 and 694 nm, respectively. The initial coarse grains are refined significantly. The initial lamellar grain structures are subdivided into pancake-shaped subgrains due to a gradual transition by triple junction motion at 473 K, and then a dramatic microstructural coarsening is observed at 523 K. It is suggested that annealing behavior of this dynamic loading structure is better considered as a continuous process of grain coarsening or continuous recovery.
To investigate the effect of dl-3n-butylphthalide (NBP) on the protection of cerebral tissue and possible mechanism on ischaemia-reperfusion injury, and to find out whether NBP therapy can extend the reperfusion window in an experimental stroke model in rats.
Seventy-two Sprague-Dawley rats were randomly divided into sham operation, ischaemia-reperfusion and ischaemia-reperfusion with NBP groups. Focal cerebral ischaemia was induced using the modified intraluminal thread method and maintained for 2, 3 or 4 h. The ischaemia-reperfusion group received reperfusion immediately after ischaemia-reperfusion. The NBP group received intraperitoneal injection of NBP immediately after ischaemia, followed by reperfusion. The sham operation group received only injection of physiological saline. The cerebral infarction volume and neurological deficit were analysed, and vascular endothelial growth factor (VEGF) expression in brain tissues was visualised by immunohistochemistry.
NBP treatment caused a significant decrease in both infarction volume and neurological deficit compared with the ischaemia-reperfusion group at corresponding time points in each (p < 0.05). In the NBP group, the infarction volume and neurological deficit did not change with different ischaemia times. The expression of VEGF was significantly decreased in the ischaemia-reperfusion group compared with the sham group (p < 0.01), while this change was partly prevented in the NBP group (p < 0.01). The expression of VEGF in brain tissue in both the NBP and ischaemia-reperfusion groups gradually decreased when the ischaemic period was prolonged.
NBP treatment has a protective effect against cerebral ischaemia; this possible mechanism maybe related to the VEGF expression and may extend the reperfusion window for subsequent salvage of cerebral ischaemia by reperfusion.
Motivated by various applications in queuing theory, this article is
devoted to the monotonicity and convexity of some functions associated
with discrete-time or continuous-time denumerable Markov chains. For the
discrete-time case, conditions for the monotonicity and convexity of the
functions are obtained by using the properties of stochastic dominance and
monotone matrix. For the continuous-time case, by using the uniformization
technique, similar results are obtained. As an application, the results
are applied to analyze the monotonicity and convexity of functions
associated with the queue length of some queuing systems.
Eu(DBM)3phen-doped poly(methyl methacryate) (PMMA) with different doping concentration were prepared. The highest doping concentration sample (10000 ppm) was examined by near-field scanning optical microscopy (NSOM) with a resolution of 50 nm; and the result showed that there were no aggregates larger than 50 nm in the doped polymer. This result was further confirmed by optical properties of the doping material. Concentration quenching was not detected by metastable-state lifetime measurements, indicating that no aggregates existed. According to the fluorescence spectra analysis, the relative intensity ratio (R) of 5D0→7F2 to 5D0→7F1 transition was not shown to be significantly changed with the increasing of Eu3+ content. The analysis reflected that the local structure and asymmetry in the vicinity of europium ions were not changed, and that the Eu3+ ions in PMMA were homogeneously dispersed.
Eu(DBM)3Phen-doped poly(methyl methacrylate) (PMMA) with different doping concentrations was prepared. Judd–Ofelt parameters Ω2 and Ω4 and the fluorescence intensity ratio R were computed from the fluorescence emission spectra and were analyzed. The radiative properties, such as transition probabilities, emission cross section (46.47 × 10−22 cm2), fluorescence branching ratios (90.34%), and radiative lifetime (1.704 ms), reveal that Eu(DBM)3 Phen-doped PMMA has potential use as a laser material.
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