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Fog plays a vital role in maintaining ecosystems in montane cloud forests. In these forests, a large amount of water on the surface of leaves and canopy (hereafter canopy water) evaporates during the morning. This biophysical process plays a critical factor in regulating afternoon fog formation. Recent studies have found that alterations in precipitation, temperature, humidity, and CO2 concentrations associated with future climate changes may affect terrestrial hydroclimatology, but the responses in cloud forests remain unclear. Utilizing numerical experiments with the Community Land Model, we explored changes in surface evaporative fluxes in Chi-Lan Mountain cloud forests in northeastern Taiwan under the RCP8.5 scenario with changes in the aforementioned various atmospheric variables. The results showed that increased rainfall intensity in climate change runs decreased the accumulation of canopy water, while larger water vapor concentrations led to more nighttime condensation on leaves. Elevated CO2 concentrations did not greatly impact canopy water amounts, but photosynthesis was enhanced, while transpiration was reduced and contributed to decreased latent heat fluxes, implying the importance of forest plant physiology in modulating land evaporative fluxes. Evapotranspiration decreased in Chi-Lan due to multiple combined factors, in contrast to the expected intensification in the global water cycle under global warming. The study, however, is restricted to an offline land surface model without land–atmosphere interactions and the interactions with adjacent grids, which deserves further analyses for the water cycle changes in the montane cloud forest regions.

雲霧森林是經常性受到雲霧籠罩所影響的森林生態系。雲霧對於當地有調節水分與能量的作用，是維持該生態系平衡的重要因子。過去研究指出，大量樹冠水在早晨受太陽加熱蒸發，造成潛熱通量的峰值提前而有利於當地雲霧生成。但在氣候變遷下，降水、溫度、濕度及二氧化碳濃度的改變可能影響樹冠水的累積，進而改變地表通量和雲霧生成。本研究利用NCAR地表過程模式，搭配棲蘭雲霧森林及蓮華池森林的大氣觀測資料，以及TCCIP模式的未來氣候推估資料，討論氣候變遷影響雲霧森林樹冠水及地表通量的機制。結果顯示未來增強的降水強度將不利於樹冠水累積，但大氣增溫造成的水氣量增加卻有助於夜間露水凝結，使氣候變遷下平均的樹冠水量增加。二氧化碳濃度的增加對樹冠水量沒有明顯影響，但會提升光合作用效率並造成氣孔縮小而使蒸散量降低。 暖化下增加的樹冠水，提升了雲霧森林在早晨的潛熱通量，但全天平均的潛熱通量則因降水截留的減少而下降，然而其中氣溫提升所造成的潛熱通量增加仍扮演緩解降水強度變強對雲霧森林衝擊的角色。植被透過蒸散作用調節其表面溫度，是暖化下有利夜間露水凝結的重要因素，而在二氧化碳提升下所增加的光合作用速率亦能調節當地二氧化碳濃度的變化，顯示雲霧森林中植被在氣候變遷下的重要性。 雲霧森林中的地表通量在氣候變遷下的改變也會同時透過陸地與大氣間的交互作用而影響到當地的大氣穩定度與邊界層發展等，因此未來將利用大氣與陸地耦合模式並考慮雲霧與山谷風環流在雲霧森林中的關係，進一步討論未來氣候變遷下雲霧森林內的水與能量循環的變化。 Cloud-fog forest is known as a forest ecosystem governed by frequent fog immersion. Fog plays a vital role in maintaining the ecosystem’s equilibrium in montane cloud forests, where a large amount of canopy water evaporates in the morning, being a critical factor for fog formation. Recent studies found that precipitation, temperature, humidity changes, and elevated CO2 concentration under climate change may affect the canopy water amount and surface fluxes in cloud forests, but the mechanisms remain unclear. We explore the changes in surface flux characteristics in the Chi-Lan montane cloud forest under climate change by using the NCAR Community Land Model, in-situ observation from Chi-Lan cloud forest and Lien-Hua-Chih forest, and future climate scenarios from TCCIP modelling outputs. Results show that the future intensified rainfall is unfavorable for canopy water accumulation, while more water vapor under future warming leads to more nighttime condensation on leaves. Elevated CO2 concentration does not greatly impact canopy water amount, but the photosynthesis efficiency is enhanced and the transpiration is suppressed under higher CO2 concentration. The combining results show overall increased canopy water under various climate changes. It promotes strong canopy evaporation when sun rises, but the total daytime evaporation still decreases due to the decreased intercepted rainfall. The response of canopy water and surface fluxes under rising temperature mitigates the impact of higher precipitation intensity on cloud forests. The regulating factor of vegetation temperature plays a critical role in the increasing canopy water under a warming climate. The increased photosynthesis under elevated CO2 weakens the local change of CO2 concentration, implying the importance of vegetation in forests under climate change. The atmosphere can interact with the land surface through the adjusted surface fluxes under climate change. Therefore, future work may require coupled land and atmosphere model simulations and considering changes of fog and local circulations in the future scenario to explore the impact of climate change on cloud forests. &nbsp

BACKGROUND: Since COVID-19 outbreak, hydroxychloroquine (HCQ) has been tested for effective therapies and the relevant researches have shown controversial results. METHODS: Systematic review and meta-analysis were conducted after a thorough search of relevant studies from databases. Trials that have evaluated HCQ for COVID-19 treatment were recruited for statistical analysis with fixed- and random-effect models. RESULTS: Nine trials involving 4,112 patients were included in present meta-analysis. It was seen that hydroxychloroquine-azithromycin (HCQ-AZI) combination regimen increased the mortality rate in COVID-19 (OR 2.34, 95% CI 1.63-3.36) patients, however, it also showed benefits associated with the viral clearance in patients (OR 27.18, 95% CI 1.29-574.32). HCQ-alone when used as a therapy in COVID-19 did not reveal significant changes in mortality rate, clinical progression, viral clearance and cardiac QT prolongation. Subsequent subgroup analysis showed that HCQ treatment could decrease mortality rate and progression to severe illness in severely-infected COVID-19 patients (OR 0.27, 95% CI 0.13-0.58). A lower risk of mortality rate was also noted in the stratified group of >14 days follow-up period (OR 0.27, 95% CI 0.13-0.58) compared to ≦14 days follow-up period group that conversely showed an increased mortality rate (OR 2.09, 95% CI 1.41-3.10). CONCLUSION: Our results indicated that HCQ-AZI combination treatment increased mortality rate in COVID-19, but it also showed benefits associated with viral clearance in patients. HCQ-alone used for treatment has revealed benefits in decreasing the mortality rate among severely-infected COVID-19 group and showed potential to be used for COVID-19 treatment in long-term follow-up period group. Accordingly, more rigorous, large-scale and long follow-up period studies in patients with COVID-19 are needed.

Since COVID-19 outbreak, hydroxychloroquine (HCQ) has been tested for effective therapies, and the relevant researches have shown controversial results.Systematic review and meta-analysis were conducted after a thorough search of relevant studies from databases. Trials that have evaluated HCQ for COVID-19 treatment were recruited for statistical analysis with fixed- and random-effect models.Nine trials involving 4112 patients were included in present meta-analysis. It was seen that HCQ-azithromycin (HCQ-AZI) combination regimen increased the mortality rate in COVID-19 (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.63-3.36) patients; however, it also showed benefits associated with the viral clearance in patients (OR, 27.18; 95% CI, 1.29-574.32). HCQ-alone when used as a therapy in COVID-19 did not reveal significant changes in mortality rate, clinical progression, viral clearance, and cardiac QT prolongation. Subsequent subgroup analysis showed that HCQ treatment could decrease mortality rate and progression to severe illness in severely infected COVID-19 patients (OR, 0.27; 95% CI, 0.13-0.58). A lower risk of mortality rate was also noted in the stratified group of14 days follow-up period (OR, 0.27; 95% CI, 0.13-0.58) compared to ≤14 days follow-up period group that conversely showed an increased mortality rate (OR, 2.09; 95% CI, 1.41-3.10).Our results indicated that HCQ-AZI combination treatment increased mortality rate in patients with COVID-19, but it also showed benefits associated with viral clearance in patients. HCQ-alone used for treatment has revealed benefits in decreasing the mortality rate among severely infected COVID-19 group and showed potential to be used for COVID-19 treatment in long-term follow-up period group. Accordingly, more rigorous, large-scale, and long follow-up period studies in patients with COVID-19 are needed.

BackgroundsSince COVID-19 outbreak, various agents have been tested but no proven effective therapies have been identified. This has led to a lot of controversies among associated researches. Hence, in order to address the issue of using hydroxychloroquine in treating COVID-19 patients, we conducted a systematic review and meta-analysis.MethodsA thorough search was carried out to find relevant studies in MEDLINE, medRxiv, PubMed, Cochrane Database, China Academic Journals Full-text Database and Web of Science. Two investigators independently reviewed 274 abstracts and 23 articles. The trials which evaluated hydroxychloroquine for treatment of COVID-19 were included for this systematic review. Two investigators assessed quality of the studies and data extraction was done by one reviewer and cross checked by the other.ResultsFive trials involving 677 patients were included while conducting the meta-analysis. Compared with the control group, hydroxychloroquine with or without azithromycin showed benefits in positive-to-negative conversion of SARS-CoV-2 (odds ratio [OR], 1.95 [95% CI,0.19 to 19.73] and a reduction in progression rate (OR, 0.89 [95% CI, 0.58 to 1.37]), but without demonstrating any statistical significance. This systematic review has also suggested a possible synergistic effect of the combination therapy which included hydroxychloroquine and azithromycin. However, the use of hydroxychloroquine alone was associated with increased mortality in COVID-19 patients.ConclusionThe use of hydroxychloroquine with or without azithromycin for treatment of COVID-19 patients, seems to be effective. The combination of hydroxychloroquine and azithromycin has shown synergic effects. However, mortality rate was increased when the treatment was conducted with hydroxychloroquine.