[1] The statistical spatial-temporal features of the intense snowfall event (ISE) in China are investigated over the period of 1962-2000. The results indicate that eastern China, northern Xinjiang, the eastern Tibetan plateau, and northeastern China are four key regions for the ISE, with more frequency and strong variability. Annual cycle analysis shows the ISE exhibits a unimodal distribution with maximum frequency at winter months for eastern China, a bimodal distribution with maximum frequency at early winter and spring months for northern Xinjiang and northeastern China, and a bimodal distribution with maximum frequency at autumn and spring months for the eastern Tibetan plateau. Linear trend analysis indicates that in the last 39 years, the ISE exhibits a decreasing trend for eastern China and an increasing trend for northern Xinjiang and the eastern Tibetan plateau. The linear trend of the ISE is weak over northeastern China. Based on the simulations of the most recent and comprehensive climate models in the 20th century run, the performance of the current climate models in simulating the Chinese ISE is investigated. The results indicate that, of the 20 models, there are four models that can reasonably reproduce the spatial-temporal features of the Chinese ISE. Based on these four models' simulation for the 21st century under A1B and A2 scenarios, the future variability of the Chinese ISE is projected. It is found that global warming will cause the ISE frequency over southern China to decrease, while the ISE over northern China will initially increase and then decrease.

[1] Temporal and spatial variations of high and low contents of Ti basalts in the Permian Emeishan large igneous province (ELIP) of southwest China and Vietnam are crucial for modeling of continental basalt formation and the nature of mantle-lithosphere interaction. A combined geochemical and magnetostratigraphic study was carried out at Yanyuan in the inner zone of the ELIP. Geochemical results indicate that the basalts are low-Ti (LT) basalts (Ti/Y ∼ 484.2-511.4) in the Luomapu section and high-Ti (HT) basalts (Ti/Y ∼ 558.2-658.9) in the Gongmushan section. Systematic paleomagnetic sampling and stepwise thermal demagnetization demonstrate that the higher temperature component shows two distinct characteristic remanent magnetizations with northeasterly upward and SWW downward directions. These results indicate a simple magnetostratigraphic normal and reversed polarity pattern from the lower and upper parts of the section, respectively. By comparing with available magnetostratigraphic and paleomagnetic data carried out in the ELIP, these results imply that the eruption of the Emeishan basalts can be divided into early (normal polarity subchron) and late (reversal subchron) stages. The early stage included LT basalts in the inner zone and most of the HT basalts in the intermediate and outer zones, and the late stage contained a part of LT and HT basalts in the upper parts of the sections in the inner zone and a few in the intermediate zone of the ELIP. Correlating with available Middle-Late Permian magnetostratigraphy and the Permian magnetic time scale, the new magnetic polarity sequence result suggests that the ELIP formed over a very short time interval (<1 Myr).

No abstract

ObjectiveThe purpose of this study was to analyze the clinical features and prognostic factors of surgical outcome of foot drop caused by lumbar degenerative disease and put forward the clinical stage.MethodsWe retrospectively reviewed 135 patients with foot drop due to lumbar degenerative disease. The clinical features and mechanism were analyzed. Age, sex, duration of palsy, preoperative muscle strength of tibialis anterior (TA), sensation defect of affected lower limb, affected foot, diagnosis and compressed nerve roots were recorded and compared with surgical outcome.ResultsFoot drop was observed in 8.1% of all inpatients of lumbar degenerative disease. L5 nerve root compression was observed in 126 of all 135 patients (93.3%). Single, double and triple roots compression was observed respectively in 43, 83, and 9 patients (31.9%, 61.5%, and 6.6%). But there was no significant relationship between preoperative muscle strength of TA and the number of compressed roots. The muscle strength of TA was improved in 113 (83.7%) patients after surgery, but it reached to >=4 in only 21 (15.6%) patients. Improvement of the muscle strength of TA was almost stable at the 6-month follow-up. At the last follow-up, the muscle strength of TA was 1, 2, 3, 4, 5 respectively in 28, 24, 62, 13, 8 patients. Multivariate logistic regression showed duration of palsy (p=0.0360, OR=2.543), preoperative muscle strength of TA (p=0.0064, OR=5.528) and age (p=0.0309, OR=3.208) were factors that influenced recovery following an operation.ConclusionsL5 nerve root was most frequently affected. The muscle strength of TA improved in most patients after surgery, but few patients can get a good recovery from foot drop. Patients of shorter duration of palsy, better preoperative muscle strength of TA and younger age showed a better surgical outcome.

No abstract

No abstract

As an ecologically sensitive region, the humid‐to‐arid climate transition zone in the eastern and central north China (ECNC) has experienced varied vegetation change in recent decades, but the exact impacts of climate change and human activities remain uncertain. Based on the Normalized Difference Vegetation Index (NDVI), we established the trend of vegetation change in the past three decades (1982–2013) in the ECNC, and examined the impact of climate and nonclimate factors on vegetation growth within the different eco‐regions. For the study period, the climate in ECNC became significantly warmer and slightly drier, and the overall NDVI increased significantly, but with great spatial variations. Our results suggest that temperature increase has promoted vegetation growth in places that are colder and/or wetter, and with higher vegetation coverage. Precipitation increase has promoted vegetation growth in drier places with sparse vegetation and inhibited growth in wet places with high vegetation coverage. As different eco‐regions typically have different vegetation coverage and occupy different climate zones, their response to climate change also varies. For the study period, increasing temperature and decreasing precipitation promoted vegetation growth in the forest of northern ECNC. Increasing temperature and precipitation led to NDVI increase in the grassland in the south, whereas grassland in the north and west showed no significant change despite temperature increase and precipitation decrease. Cropland responded mostly positively to temperature increase, although correlations between NDVI and climate factors were generally weaker. Using multiple regression models, we found that 60% of the NDVI increase was attributed to climate factors whereas the remaining 40% was likely caused by human activities. Although farming practices and crop rotations might have caused significant decrease in NDVI in small areas, human impact largely led to significant NDVI increase in the grass‐crop transition zones, most likely due to ecological restoration programs.

No abstract