The active layer,acting as an intermediary of water and heat exchange between permafrost and atmosphere,greatly influences biogeochemical cycles in permafrost areas and is notably sensitive to climate fluctuations.Uti...The active layer,acting as an intermediary of water and heat exchange between permafrost and atmosphere,greatly influences biogeochemical cycles in permafrost areas and is notably sensitive to climate fluctuations.Utilizing the Chinese Meteorological Forcing Dataset to drive the Community Land Model,version 5.0,this study simulates the spatial and temporal characteristics of active layer thickness(ALT)on the Tibetan Plateau(TP)from 1980 to 2020.Results show that the ALT,primarily observed in the central and western parts of the TP where there are insufficient station observations,exhibits significant interdecadal changes after 2000.The average thickness on the TP decreases from 2.54 m during 1980–1999 to 2.28 m during 2000–2020.This change is mainly observed in the western permafrost region,displaying a sharp regional inconsistency compared to the eastern region.A persistent increasing trend of ALT is found in the eastern permafrost region,rather than an interdecadal change.The aforementioned changes in ALT are closely tied to the variations in the surrounding atmospheric environment,particularly air temperature.Additionally,the area of the active layer on the TP displays a profound interdecadal change around 2000,arising from the permafrost thawing and forming.It consistently decreases before 2000 but barely changes after 2000.The regional variation in the permafrost active layer over the TP revealed in this study indicates a complex response of the contemporary climate under global warming.展开更多
In nature, Apostichopus japonicus exhibits a behavioral characteristic of emerging at night and sheltering during the day. Hence, it was commonly believed that longer and darker light conditions are better for a popul...In nature, Apostichopus japonicus exhibits a behavioral characteristic of emerging at night and sheltering during the day. Hence, it was commonly believed that longer and darker light conditions are better for a population of A. japonicus. In aquaculture situations therefore, animals have commonly been cultured without lighting, especially during juvenile-hatching culture. However, how the length of darkness each day affects .4.japonicus and what the mechanism is of behavioral response of A. japonicus to different photoperiods remain unclear, and are specifically addressed in this study. We applied nine photoperiod treatments （light：dark （LD） cycles at 0：24, 3：21, 6：18, 9：15, 12：12, 15：9, 18：6, 21：3, and 24：0 under 500Ix） to 60 individuals （29.73±0.23 g） per treatment （with 3 replicates）. The enviroramental conditions were set as： water temperature = 16.9±0.3℃, dissolved oxygen〉6.0 rag/L, ammonia〈0.3 mg/L, pH=7.8-8.2, and salinity=30-32. Under experimental conditions of continuous darkness as well as continuous light, cyclic nocturnal activity patterns of A. japonicus （viz. the animals emerged and fed at night and sheltered during the day） were observed. However, they spent more and less time, respectively, moving and feeding under continuous darkness and continuous light, than those under a natural light cycle. Under photoperiods with 6-12 h of light, the animals showed one sheltering behavior transition and two emerging behavior transitions. These behavior transitions appeared to be governed by some internal physiological factors and induced by daily light variation. The behavior of the animals was significantly affected by different photoperiods, and the distribution rate （DR） of the animals emerging at ＂daytime＂ increased with lengthening ＂light time＂ （except for the LD 3：21 cycle）. We also found that there was no significant difference in mean DR per day under LD cycles of 6：18, 9：15, 15：9, and 12：12. Mean DRs per day were significantly lower for these photoperiods, than for those under LD cycles of 0：24 and 3：21, and significantly higher than for those under LD cycles of 18：6, 21：3 and 24：0. These results imply that 6-15 h light per day were the similar photoperiods to natural sunlight. From the viewpoint of activity and feeding behaviors, these might be the optimal photoperiods for rearing A. japonicus.展开更多
AIM:To examine the clinicopathologic features of elderly patients with gastric carcinoma and to investigate the relationship between prognosis and age.METHODS: We reviewed the hospital records of 2 014patients with ga...AIM:To examine the clinicopathologic features of elderly patients with gastric carcinoma and to investigate the relationship between prognosis and age.METHODS: We reviewed the hospital records of 2 014patients with gastric carcinoma retrospectively to compare the clinicopathologic findings in elderly (age ＞70 years) and young (age ＜36 years) patients during the period from 1986 to 2000 in a tertiary referral center in Gwangju, Korea. Overall survival was the main outcome measure.RESULTS: Of the 2 014 patients, 194 (9.6%) were in the elderly group and 137 (6.8%) were in the young group.The elderly and young patients had similar distributions with respect to depth of invasion, nodal involvement, hepatic metastasis, peritoneal dissemination, tumor stage at the initial diagnosis, and type of surgery. Synchronous multiple carcinomas were found in 14/194 (7.2%) of the elderly group and 4/137 (2.9%) of the young group (P＜0.05). Using the Borrmann classification, type Ⅳ was more frequent in the young patients than in the elderly patients (P＜0.05).Significantly more elderly patients had a well or moderately differentiated histology, and more young patients had a poorly differentiated histology and signet ring cell carcinoma (P＜0.001). The 5-year survival rates of elderly and young patients did not differ statistically (52.8% vs 46.5%,P = 0.5290). Multivariate analysis showed that the histologic type, nodal involvement and operative curability were significant prognostic factors, and age itself was not an independent prognostic factor of survival for elderly gastric carcinoma patients.CONCLUSION: Elderly patients with gastric carcinoma do not have a worse prognosis than young patients. The important prognostic factor is whether the patients undergo a curative resection.展开更多
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program[grant number 2019QZKK0102]the Youth Innovation Promotion Association CAS[grant number 2021073]the special fund of the Yunnan University“double firstclass”construction.
文摘The active layer,acting as an intermediary of water and heat exchange between permafrost and atmosphere,greatly influences biogeochemical cycles in permafrost areas and is notably sensitive to climate fluctuations.Utilizing the Chinese Meteorological Forcing Dataset to drive the Community Land Model,version 5.0,this study simulates the spatial and temporal characteristics of active layer thickness(ALT)on the Tibetan Plateau(TP)from 1980 to 2020.Results show that the ALT,primarily observed in the central and western parts of the TP where there are insufficient station observations,exhibits significant interdecadal changes after 2000.The average thickness on the TP decreases from 2.54 m during 1980–1999 to 2.28 m during 2000–2020.This change is mainly observed in the western permafrost region,displaying a sharp regional inconsistency compared to the eastern region.A persistent increasing trend of ALT is found in the eastern permafrost region,rather than an interdecadal change.The aforementioned changes in ALT are closely tied to the variations in the surrounding atmospheric environment,particularly air temperature.Additionally,the area of the active layer on the TP displays a profound interdecadal change around 2000,arising from the permafrost thawing and forming.It consistently decreases before 2000 but barely changes after 2000.The regional variation in the permafrost active layer over the TP revealed in this study indicates a complex response of the contemporary climate under global warming.
基金Supported by the National Natural Science Foundation of China (Nos. 30871931, 30771661)the National Key Technology Research and Development Program of China (Nos. 2006BAD09A01)the National Special Research Fund for Non-Profit Sector (No. 200905020)
文摘In nature, Apostichopus japonicus exhibits a behavioral characteristic of emerging at night and sheltering during the day. Hence, it was commonly believed that longer and darker light conditions are better for a population of A. japonicus. In aquaculture situations therefore, animals have commonly been cultured without lighting, especially during juvenile-hatching culture. However, how the length of darkness each day affects .4.japonicus and what the mechanism is of behavioral response of A. japonicus to different photoperiods remain unclear, and are specifically addressed in this study. We applied nine photoperiod treatments （light：dark （LD） cycles at 0：24, 3：21, 6：18, 9：15, 12：12, 15：9, 18：6, 21：3, and 24：0 under 500Ix） to 60 individuals （29.73±0.23 g） per treatment （with 3 replicates）. The enviroramental conditions were set as： water temperature = 16.9±0.3℃, dissolved oxygen〉6.0 rag/L, ammonia〈0.3 mg/L, pH=7.8-8.2, and salinity=30-32. Under experimental conditions of continuous darkness as well as continuous light, cyclic nocturnal activity patterns of A. japonicus （viz. the animals emerged and fed at night and sheltered during the day） were observed. However, they spent more and less time, respectively, moving and feeding under continuous darkness and continuous light, than those under a natural light cycle. Under photoperiods with 6-12 h of light, the animals showed one sheltering behavior transition and two emerging behavior transitions. These behavior transitions appeared to be governed by some internal physiological factors and induced by daily light variation. The behavior of the animals was significantly affected by different photoperiods, and the distribution rate （DR） of the animals emerging at ＂daytime＂ increased with lengthening ＂light time＂ （except for the LD 3：21 cycle）. We also found that there was no significant difference in mean DR per day under LD cycles of 6：18, 9：15, 15：9, and 12：12. Mean DRs per day were significantly lower for these photoperiods, than for those under LD cycles of 0：24 and 3：21, and significantly higher than for those under LD cycles of 18：6, 21：3 and 24：0. These results imply that 6-15 h light per day were the similar photoperiods to natural sunlight. From the viewpoint of activity and feeding behaviors, these might be the optimal photoperiods for rearing A. japonicus.
文摘AIM:To examine the clinicopathologic features of elderly patients with gastric carcinoma and to investigate the relationship between prognosis and age.METHODS: We reviewed the hospital records of 2 014patients with gastric carcinoma retrospectively to compare the clinicopathologic findings in elderly (age ＞70 years) and young (age ＜36 years) patients during the period from 1986 to 2000 in a tertiary referral center in Gwangju, Korea. Overall survival was the main outcome measure.RESULTS: Of the 2 014 patients, 194 (9.6%) were in the elderly group and 137 (6.8%) were in the young group.The elderly and young patients had similar distributions with respect to depth of invasion, nodal involvement, hepatic metastasis, peritoneal dissemination, tumor stage at the initial diagnosis, and type of surgery. Synchronous multiple carcinomas were found in 14/194 (7.2%) of the elderly group and 4/137 (2.9%) of the young group (P＜0.05). Using the Borrmann classification, type Ⅳ was more frequent in the young patients than in the elderly patients (P＜0.05).Significantly more elderly patients had a well or moderately differentiated histology, and more young patients had a poorly differentiated histology and signet ring cell carcinoma (P＜0.001). The 5-year survival rates of elderly and young patients did not differ statistically (52.8% vs 46.5%,P = 0.5290). Multivariate analysis showed that the histologic type, nodal involvement and operative curability were significant prognostic factors, and age itself was not an independent prognostic factor of survival for elderly gastric carcinoma patients.CONCLUSION: Elderly patients with gastric carcinoma do not have a worse prognosis than young patients. The important prognostic factor is whether the patients undergo a curative resection.
