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Studying the seed trait–stem trait–individual spatial pattern system is helpful for understanding the developmental direction of plant dynamics and populations under grazing disturbance as well as the antagonistic relationship between animals and plants, but few systematic analyses of this spatial pattern system have been carried out. Kobresia humilis is the dominant species in alpine grasslands. We studied K. humilis seed traits and their relationship with K. humilis reproductive individuals, the relationship between reproductive and vegetative stems, and the weights and spatial patterns of reproductive and nonreproductive individuals under four grazing treatments: no grazing (control), light grazing, moderate grazing and heavy grazing. We explored the relationship among seed size and seed number with reproductive stems and vegetative stems along the grazing gradient and assessed the spatial pattern changes between reproductive and nonreproductive individuals. The results showed the following: (1) Seed size increased with increasing grazing intensity, and the coefficient of variation for seed size and seed number in the heavy grazing treatment was greater than 0.6. (2) The structural equation model showed that grazing treatment had a positive effect on seed number, seed size and reproductive stem number and a negative effect on reproductive stem weight. (3) Grazing treatment did not affect the resource allocation to reproductive stems and vegetative stems per unit length of reproductive K. humilis individuals. (4) Compared with the number of reproductive individuals in the no grazing treatment, the number in the heavy grazing treatment decreased significantly, and the negative correlation between reproductive individuals and nonreproductive individuals changed from a full-scale negative correlation to a small-scale negative correlation and a large-scale positive correlation. Our study showed that grazing could activate and change the resource allocation pattern of dominant species in a grassland and have significant positive effects on reproductive stem number, reproductive stem weight, seed number and seed size. Along a grazing intensity gradient, with the increase in distance between reproductive and nonreproductive individuals, the transformation of intraspecific relationships from a negative correlation to a positive correlation is an ecological strategy conducive to population survival.

Studying the seed trait-stem trait-individual spatial pattern system is helpful for understanding the developmental direction of plant dynamics and populations under grazing disturbance as well as the antagonistic relationship between animals and plants, but few systematic analyses of this spatial pattern system have been carried out. Kobresia humilis is the dominant species in alpine grasslands. We studied K. humilis seed traits and their relationship with K. humilis reproductive individuals, the relationship between reproductive and vegetative stems, and the weights and spatial patterns of reproductive and nonreproductive individuals under four grazing treatments: no grazing (control), light grazing, moderate grazing and heavy grazing. We explored the relationship among seed size and seed number with reproductive stems and vegetative stems along the grazing gradient and assessed the spatial pattern changes between reproductive and nonreproductive individuals. The results showed the following: (1) Seed size increased with increasing grazing intensity, and the coefficient of variation for seed size and seed number in the heavy grazing treatment was greater than 0.6. (2) The structural equation model showed that grazing treatment had a positive effect on seed number, seed size and reproductive stem number and a negative effect on reproductive stem weight. (3) Grazing treatment did not affect the resource allocation to reproductive stems and vegetative stems per unit length of reproductive K. humilis individuals. (4) Compared with the number of reproductive individuals in the no grazing treatment, the number in the heavy grazing treatment decreased significantly, and the negative correlation between reproductive individuals and nonreproductive individuals changed from a full-scale negative correlation to a small-scale negative correlation and a large-scale positive correlation. Our study showed that grazing could activate and change the resource allocation pattern of dominant species in a grassland and have significant positive effects on reproductive stem number, reproductive stem weight, seed number and seed size. Along a grazing intensity gradient, with the increase in distance between reproductive and nonreproductive individuals, the transformation of intraspecific relationships from a negative correlation to a positive correlation is an ecological strategy conducive to population survival. [ABSTRACT FROM AUTHOR]

Background Response-dose ratio (RDR) and cumulative provocative dosage (PD) are useful indices reflecting airway responsiveness in asthma. Objectives To compare the diagnostic value of RDR and PD, by conducting leukotriene D.sub.4 (LTD.sub.4-BPT) and methacholine bronchial provocation test (MCh-BPT), in different asthma control levels. Methods Healthy subjects and asthmatic patients underwent LTD.sub.4-BPT and MCh-BPT, at 2-14-day interval. This entailed assessment of the distribution characteristics, correlation, and diagnostic value of PD inducing 20 % fall in forced expiratory volume in one second (PD.sub.20FEV.sub.1) and the RDR, defined as FEV.sub.1 fall (%) at the final step divided by the corresponding provocative dosage. Results Twenty uncontrolled, 22 partly controlled, 20 controlled asthmatics, and 21 healthy subjects were enrolled. Log.sub.10RDR was positively correlated with log.sub.10PD.sub.20FEV.sub.1 in both BPTs (all P < 0.05). Poorer asthma control was associated with significantly lower PD.sub.20FEV.sub.1 and higher RDR (both P < 0.05). The differences in PD.sub.20FEV.sub.1 and RDR between partly controlled and controlled asthma were unremarkable (both P > 0.05). Compared with log.sub.10PD.sub.20FEV.sub.1, the log.sub.10RDR yielded similar diagnostic values in both BPTs. A lower percentile of RDR (≤25th percentile) was associated with higher baseline FEV.sub.1 (P < 0.05) and an increased proportion of well-controlled asthmatic patients. The combination of RDR and PD.sub.20FEV.sub.1 led to an increased diagnostic value compared with either parameter alone. Conclusions RDR is a surrogate of PD.sub.20FEV.sub.1 for BPTs in asthma. This finding was not modified by different asthma control levels or the types of bronchoprovocants., Author(s): Wei-jie Guan[sup.1] , Jin-ping Zheng[sup.1] , Xu Shi[sup.1] , Yan-qing Xie[sup.1] , Cai-yu Jiang[sup.1] [sup.2] , Yi Gao[sup.1] , Zheng Zhu[sup.1] , Jia-ying An[sup.1] , Xin-xin Yu[sup.1] , Wen-ting [...]

Based on the uncommon Kramers ions CeIII, SmIII and YbIII, complexes [Ce(dppbO2)2Cl3] (1, dppbO2 = 1,2-bis(diphenylphosphino)benzene dioxide), [Sm(dppbO2)2Cl3] (2) and [Yb(dppbO2)2Cl2]Cl (3) toward single-ion magnets were obtained and fully characterized. Complexes 1 and 2 are isostructural seven-coordinate with distorted geometries between a capped trigonal prism and a capped octahedron, while 3 is six-coordinate with an octahedral geometry. Dynamic magnetic property measurements reveal their field induced slow magnetic relaxation behaviours. Fits to the temperature dependent relaxation time (τ) result in effective barriers of 38(2), 11.7(2) and 20.2(6) cm−1 for 1, 2 and 3, respectively, as well as relatively low Raman exponents (3.4(2) for 1 and 2.1(1) for 3). Ab initio calculations were then performed and they indicated that the first excited Kramers doublets (KDs) for 1, 2 and 3 lie at ca. 291, 63.5 and 137 cm−1, respectively, which are much higher than the fitting results. Combining the significant transverse magnetic moments between the ground state KDs and the first excited KDs, we thus attribute the dominant relaxation pathway of the three compounds to a Raman process, while quantum tunnelling of magnetization and direct relaxation processes may coexist. In this case, the obtained effective barriers in a high temperature region for 1 and 3 are actually the energies of the vibrational modes, which lead to second-order Raman processes with exponential temperature dependence. [ABSTRACT FROM AUTHOR]