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1.
Proc Natl Acad Sci U S A ; 118(33)2021 08 17.
Artículo en Inglés | MEDLINE | ID: mdl-34373324

RESUMEN

High-latitude and high-altitude regions contain vast stores of permafrost carbon. Climate warming may result in the release of CO2 from both the thawing of permafrost and accelerated autotrophic respiration, but it may also increase the fixation of CO2 by plants, which could relieve or even offset the CO2 losses. The Tibetan Plateau contains the largest area of alpine permafrost on Earth. However, the current status of the net CO2 balance and feedbacks to warming remain unclear, given that the region has recently experienced an atmospheric warming rate of over 0.3 °C decade-1 We examined 32 eddy covariance sites and found an unexpected net CO2 sink during 2002 to 2020 (26 of the sites yielded a net CO2 sink) that was four times the amount previously estimated. The CO2 sink peaked at an altitude of roughly 4,000 m, with the sink at lower and higher altitudes limited by a low carbon use efficiency and a cold, dry climate, respectively. The fixation of CO2 in summer is more dependent on temperature than the loss of CO2 than it is in the winter months, especially at higher altitudes. Consistently, 16 manipulative experiments and 18 model simulations showed that the fixation of CO2 by plants will outpace the loss of CO2 under a wetting-warming climate until the 2090s (178 to 318 Tg C y-1). We therefore suggest that there is a plant-dominated negative feedback to climate warming on the Tibetan Plateau.


Asunto(s)
Altitud , Dióxido de Carbono/metabolismo , Simulación por Computador , Modelos Biológicos , Hielos Perennes , Plantas/metabolismo , Ciclo del Carbono , Cambio Climático , Ecosistema , Estaciones del Año , Tibet
2.
Open Med (Wars) ; 19(1): 20240969, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38799250

RESUMEN

Intercellular adhesion molecule-1 (ICAM-1) is related to the occurrence and development of a variety of tumors. However, the role of ICAM-1 in the regulation of growth, metastasis, and clinical prognosis of the specific molecular subtypes of breast cancer, triple-negative breast cancer (TNBC), remains to be elucidated. This study explored the role of ICAM-1 in breast cancer and its triple-negative subtypes by systematic bioinformatics methods. The results showed that the expression of ICAM-1 in breast cancer tissues was significantly higher than that in normal tissues, especially in TNBC subtypes. In breast cancer, ICAM-1 mainly activates pathways related to apoptosis and epithelial-mesenchymal transition, while its overexpression in TNBC is associated with inflammatory response, apoptosis, and other processes. TNBC patients displaying higher ICAM-1 expression demonstrate enhanced responses to immunotherapy. High ICAM-1 expression is sensitive to drugs targeting tumor cell proliferation, apoptosis, and angiogenesis. In conclusion, breast cancer is characterized by significantly high expression of ICAM-1, with TNBC subtypes expressing ICAM-1 at much higher levels than other subtypes. The diagnosis, prognosis, development, distant metastases, and immunotherapy of TNBC are correlated with high expression of ICAM-1. This research provides available data for the further study of the diagnosis and treatment of TNBC.

3.
Spectrochim Acta A Mol Biomol Spectrosc ; 281: 121628, 2022 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-35863185

RESUMEN

In this paper, a high-resolution absorption spectrometer based on a continuous wave (CW) distributed feedback (DFB) diode laser near 2682.8 nm spectral region is developed, which is suitable for high sensitive detection of trace CO2 and H2O simultaneously. Spectral parameters (line strengths, air- and self-broadening coefficients) for CO2 absorption line at 3727.08279 cm-1 and H2O absorption line at 3727.73765 cm-1 are experimentally investigated, and a good agreement was obtained by comparing with the HITRAN database. H2O induced CO2 broadening coefficient is especially measured to upgrade the spectral signal processing algorithm model for field application. Finally, the developed diode laser absorption spectrometer was continuously deployed at AECORSQ Observatory onMt. Qomolangma, China, for approximate two days, which demonstrated the high sensitivity and stability of the sensor system for continuously atmospheric CO2 and H2O background observation.

4.
Sci Total Environ ; 823: 153545, 2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35104526

RESUMEN

An influence of precipitation on the glacier changes over the Qinghai-Tibet Plateau (QTP) is investigated in this paper. The results show that the glacial loss rates of glaciers in the QTP are significantly correlated with the interannual changes of precipitation and low cloud cover. The water vapor, importing with the warm and wet airflows from the Asian Monsoon regions, significantly influence the precipitation in the southern and northern glacier areas of the QTP in the summer monsoon season. The three-dimensional changes of water vapor transport can lead to the difference of water balance between different glacier areas. Under global warming, the northwest QTP is in the ascending branch of the vertical water driven thermally by the tropical Indian Ocean. The warm water vapor from the tropical ocean climbs to the QTP, forming a significant supply effect of precipitation in the northwestern glacier area, which makes the glacier retreat at a relatively slow rate. Meanwhile, the southern and southeastern QTP regions are in the descending branch of vapor transport with the declining trend in the lower troposphere, which lead to the shortage water supply aggravating the glacier loss in the southern and southeastern QTP.


Asunto(s)
Monitoreo del Ambiente , Cubierta de Hielo , Vapor , Calentamiento Global , Océano Índico , Estaciones del Año , Tibet , Clima Tropical
5.
Sci Adv ; 6(26): eaay8558, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32637590

RESUMEN

Lake evaporation can influence basin-wide hydrological cycles and is an important factor in loss of water resources in endorheic lakes of the Tibetan Plateau. Because of the scarcity of data, published lake evaporation values are inconsistent, and their spatial distribution has never been reported. Presenting a plausible hypothesis of energy balance during the ice-free seasons, we explored the multiyear (2003-2016) average ice phenology and evaporation amounts of 75 large dimictic lakes by using a combination of meteorological and satellite data. Evaporation amounts show large variability in spatial distribution, with a pattern of higher values in the south. Lakes with higher elevation, smaller area, and higher latitude are generally associated with a shorter ice-free season and lower evaporation. The total evaporated water amounts have values of approximately 29.4 ± 1.2 km3 year-1 for the 75 studied lakes and 51.7 ± 2.1 km3 year-1 for all plateau lakes included.

6.
PLoS One ; 14(12): e0226373, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31841539

RESUMEN

In this study, the initial soil moisture in an atmospheric model was varied by assimilating AMSR-E (The Advanced Microwave Scanning Radiometer for EOS) products, and the results were compared with the default model scenario and in-situ data based on long-term CAMP/Tibet (Coordinated Enhanced Observing Period (CEOP) Asia-Australia Monsoon Project (CAMP) Tibet) observations. The differences between the obtained results (i.e., the new simulation, default model configuration and in-situ data) showed an apparent inconsistency in the model-simulated land surface heat fluxes. The results showed that the soil moisture was sensitive to the specific model simulation. To evaluate and verify the model stability, a long-term modeling study with AMSR-E soil moisture data assimilation was performed. Based on test simulations, AMSR-E data were assimilated into an atmospheric model for July and August 2007. The results showed that the land surface fluxes agreed well with both the in-situ data and the results of the default model configuration. Assimilating the AMSR-E SM products was important for determining the land surface heat fluxes in the WRF model. All the assimilation work substantially improved the modeling of land surface heat fluxes. Land surface heat fluxes are related to atmospheric interactions. Therefore, land surface heat fluxes are very important land surface parameters during these processes. Therefore, the simulation can be used to retrieve land surface heat fluxes from an atmospheric model. It is important to study the surface heating sources that are related to both the water and energy cycles over the Tibetan Plateau.


Asunto(s)
Monitoreo del Ambiente , Modelos Teóricos , Suelo/química , Agua/análisis , Atmósfera/análisis , Monitoreo del Ambiente/métodos , Mapeo Geográfico , Calor , Humanos , Humedad , Tibet , Factores de Tiempo
7.
Sci Rep ; 7: 44574, 2017 03 13.
Artículo en Inglés | MEDLINE | ID: mdl-28287648

RESUMEN

The Tibetan Plateau is an important water source in Asia. As the "Third Pole" of the Earth, the Tibetan Plateau has significant dynamic and thermal effects on East Asian climate patterns, the Asian monsoon process and atmospheric circulation in the Northern Hemisphere. However, little systematic knowledge is available regarding the changing climate system of the Tibetan Plateau and the mechanisms underlying its impact on East Asia. This study was based on "water-cryosphere-atmosphere-biology" multi-sphere interactions, primarily considering global climate change in relation to the Tibetan Plateau -East Asia climate system and its mechanisms. This study also analyzed the Tibetan Plateau to clarify global climate change by considering multi-sphere energy and water processes. Additionally, the impacts of climate change in East Asia and the associated impact mechanisms were revealed, and changes in water cycle processes and water conversion mechanisms were studied. The changes in surface thermal anomalies, vegetation, local circulation and the atmospheric heat source on the Tibetan Plateau were studied, specifically, their effects on the East Asian monsoon and energy balance mechanisms. Additionally, the relationships between heating mechanisms and monsoon changes were explored.

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