RESUMO
The spatial characteristics of element flow and its spillover are important topics in economics, sociology, and geography, and significant to the promotion of the coordinated development of urban agglomerations. To study element flow in the Lanxi urban agglomeration and its effect to economic development, the spatial network characteristics and economic spillover effect were studied using the methods of spatial network analysis, the spatial Durbin model, and spatial effect decomposition. The results showed that (1) the scale of element flow in the Lanxi urban agglomeration is in an unbalanced distribution state, the scale of element flow in Lanzhou and Xining is higher than that in surrounding cities, and the connection between surrounding cities is also higher than that between other cities; (2) the network structure of element flow in the Lanxi urban agglomeration is relatively intensive, with Lanzhou and Xining as the center of element concentration, which indicates an obvious 'center periphery' structure, and gradually spreads from the core area to the surrounding areas; and (3) the element concentration level of the Lanxi urban agglomeration has a significant positive spillover effect, which plays a significant role in driving the development of surrounding cities. Other factors, such as the social consumption level, have significant direct effects, whereas the industrial structure and residents' income have significant direct and spillover effects, and are the main factors that affect the coordinated development of the regional economy.
Assuntos
Cidades , China , Humanos , Desenvolvimento Econômico , Urbanização , Análise EspacialRESUMO
Plant leaf morphological and photosynthetic physiological characteristics are key functional traits in the adaptability of plants to heterogeneous environments. Analysis of the correlation between leaf morphological traits and photosynthetic physiological characteristics of salt marsh plants is helpful to deepen our understanding of how salt marsh plants adjust their leaf structure and function to adapt to their environment. However, there have been few studies on the relationship between leaf morphology and photosynthetic physiological characteristics of plants in inland salt marshes under a habitat gradient. A Phragmites australis community was divided into three plots based on differences in the wetland habitat conditions: a remote water area (plot I, 400-550 m from the water margin), a middle water area (plot II, 200-350 m from the water margin) and a near water area (plot III, 0-150 m from the water margin). The relationship between leaf morphological traits and photosynthetic physiological parameters of P. australis in heterogeneous habitats was studied. The results showed that as the habitat conditions changed from plot I to plot III, the soil characteristics, above-ground characteristics of the community and the photosynthetically active radiation changed significantly (P < 0.05). Besides, there was a highly significant positive correlation (P < 0.01) between leaf dry weight (LDW) and net photosynthetic rate (P n), the effective quantum yield of PSII photochemistry (Y(II), actual photochemical efficiency of PSII) and photochemical quenching (QP); and between leaf area and P n, Y(II) and QP in the three habitats. Moreover, in plot I, P. australis tended to have small and thick leaves with a low LDW and specific leaf area. In plot III, leaves were large and thin to adapt to the change in habitat conditions. This study provides a scientific theoretical basis for understanding the ecological adaptation strategies of plants in the harsh environment of an inland salt marsh and the conservation and management of wetland plants.
RESUMO
@#Abstract: To analyze the clinical, therapeutic and laboratory characteristics of disseminated cryptococcosis caused by Cryptococcus neoformans invading the blood stream in patient with liver cirrhosis and splenectomy. A 30-year-old male underwent splenectomy plus pericardial devascularization due to "splenomegaly and hypersplenism" in March in 2016. The patient had intermittent fever after operation for many times, and successively accompanied with back pain, left lower limb abscess and right hip pain. The highest body temperature was 39 ℃. CT and MRI revealed the lung lesion and multiple bone destruction. During that period, the effect of antibiotics was not good. On April 19th, 2017, Gram's stain, India ink stain, API 32C, Vitek 2 Compact, ribosomal ITS and IGS sequence analysis were performed to identify the strain isolated from the pus and blood stream. The serum of the patient was detected for cryptococcal antigen. Antifungal susceptibility test was used to determine drug sensitivity and minimum inhibitory concentration (MIC). The Cryptococcus neoformans isolated from fresh pus specimen showed a prominent, thick capsule after India ink stain. The colonies isolated from pus and blood stream were identified Cryptococcus neoformans using API 32C, Vitek 2 Compact, and sequence analysis of rDNA ITS and IGS. Cryptococcal capsule antigen was positive. The minimal inhibitory concentrations of 5-Flucytosine, amphotericin B, fluconazole, itriconazole, voriconazole against the isolate were <4 μg/mL, <0.5 μg/mL, 4 μg/mL, ≤0.25 μg/mL, 0.125 μg/mL respectively. The patient was initially treated with intravenous amphotericin B and flucytosine. After anti-Cryptococcus treatment for two months, the patient clinically improved, and the lesions were reduced on a follow-up CT scan. The patient made a full functional recovery after treatment for six months. Cryptococcosis has hidden onset, atypical clinical symptoms and lack of specificity. Blood stream is the main channel for Cryptococcus to spread and involve many organs of the whole body, including skin, bone and so on. Therefore, early use of blood culture to monitor blood flow dissemination, actively removing the primary focus and cutting off the infection route in time and carrying out effective anti-Cryptococcus treatment are conducive to the patient's early recovery.
RESUMO
Soil aggregation is closely related to the soil organic carbon sequestration, both of which plays an important role in the stability of the soil carbon pool. However, the results of the impact of yak grazing intensity on the soil carbon process in alpine meadows have been unclear. With the marsh meadow as the research object in the Gahai wetland of the east Qinghai-Tibet Plateau, we analyzed the influence of different grazing intensities on the allocation of mass, stability and aggregate-associated organic carbon content of aggregates in the surface soil (0-20cm) of pasture by the Le Bissonnais method. The results showed that the mass of aggregates in the particle size class of > 0.2-mm was the highest among the pastures with different grazing intensities. Compared with the no grazing grassland, light grazing promoted the formation of macro aggregates in the particle size class of > 1-mm and improved the stability of soil aggregates. The degree of soil agglomerations and stability of aggregates decreased, and the macro aggregates gradually transformed into micro aggregates (< 0.05-mm class) in moderately and heavily grazed pastures. The > 2-mm and < 0.05-mm classes of particle size had a strong fixation effect on organic carbon. Light grazing promoted the accumulation of organic carbon in this particle size aggregate, and moderate and heavy grazing accelerated the decomposition of organic carbon. There was no significant difference in organic carbon in other particle size aggregates among different grasslands (P > 0.05). This result shows that light grazing, which is a reasonable yak grazing intensity in the study area, is conducive to the formation of a good soil structure in the area and improves the soil carbon sequestration capacity.
