Site-dependent growth responses to climate in two major tree species from tropical dry forests of southwest Ecuador

Tropical dry forests (hereafter TDFs) have been extensively logged and converted into croplands or grasslands worldwide. Tumbesian forests in southwest Ecuador are among the most diverse and endangered TDFs. They face seasonal droughts of varied severity and are also subjected to episodic very wet and cloudy conditions during El Niño events. However, we lack a local quantification of their responses to regional climate (temperature, precipitation, cloud cover) and El Niño which could change across sites. Here we use dendrochronology to quantify the radial-growth rates and the responses to climate (mean temperatures, precipitation amount, cloud cover and drought severity) of two major tree species forming annual rings (Geoffroea spinosa, Handroanthus chrysanthus) in three TDFs with different local climate conditions. The lowest (1.0 mm yr⁻¹) and the highest (2.1 mm yr⁻¹) radial-growth rates of both tree species were found in the hottest-driest and moderately hot sites, respectively. G. spinosa growth responded positively to wet, cool and cloudy conditions in the hottest-driest and moderately hot sites, but the most intense response to drought was observed in the driest site at 1–5 months long scales. H. chrysanthus growth reacted positively to high growing-season precipitation in all sites, particularly in the driest site, and to cloudy conditions in moderately hot sites. The growth of H. chrysanthus was negatively associated to the Southern Oscillation Index in the dry-hot and in the moderately hot sites. Tree species coexisting in TDFs show varied growth responses to regional weather variability, drought severity and El Niño events across sites with different local climate conditions.     

How aridity variations affect Prosopis caldenia growth in transitional forests in the semiarid Argentinean Pampas

The semiarid Pampas in central Argentina, occupied by caldén’s (Prosopis caldenia Burkart) woodlands (caldenales), had been affected by several wet and dry periods in the last century. Nowadays, the caldenales cover about 17 million hectares of central Argentina and their current state is critical due to massive deforestation rates. Caldén has an important dendrochronological potential since it produces sensitive tree rings linked to climate oscillations, fire events, competence, insect breakout, among others. The standard dendrochronological analysis can be improved with new advances in serial modeling and multivariate ordination techniques for handling problems related to the comparison of dendrochronological samples. We applied a statistical algorithm, BIOdry, which integrates conventional procedures for modeling patterns between annual diameter increments and drought. P. caldenia dendrochronological data were used accounting for multiple sources of variation from the sample design, and comparing patterns from contrasting climatic portions of the study site. The relation between diameter growth dynamics of caldén with temperature and precipitation fluctuations along the second half of the last century was analyzed. Populations at the Northern limit of its natural distribution area were selected. Monthly temperature and precipitation were evaluated in order to identify relative water surplus and deficit periods and an annual aridity index (AAI) was calculated. The objectives of the present work were: to analyze, describe and model response patterns between the P. caldenia diameter growth increment and the AAIs. A common growth response pattern and differences in tree and population level were also analysed. The algorithm BIOdry showed a good behavior, according to the considered statistical parameters (all the fixed effects were statistically significant). Several and common problems associated with the nature of the tree-ring data in modeling (pseudorreplication, autocorrelation, and nested random effects) were efficiently addressed. P. caldenia diameter growth, at tree level significantly responds to different AAI variation intensities along the studied period. A high frequency growth variability at population level was detected when trees establishment happened. These associations ended when trees become older. Low frequency growth variability at population level was significant throughout the analyzed period, presumably linked to age and management history. These results provide news insights in relation to the climate impact on growth dynamics of caldén in the Argentinean pampas and the value of new statistical tools in order to improve dendrochronological studies.     

Global effects of plant litter alterations on soil CO2 to the atmosphere

Soil respiration (Rs) is the largest terrestrial carbon (C) efflux to the atmosphere and is predicted to increase drastically through global warming. However, the responses of Rs to global warming are complicated by the fact that terrestrial plant growth and the subsequent input of plant litter to soil are also altered by ongoing climate change and human activities. Despite a number of experiments established in various ecosystems around the world, it remains a challenge to predict the magnitude and direction of changes in Rs and its temperature sensitivity (Q₁₀) due to litter alteration. We present a meta‐analysis of 100 published studies to examine the responses of Rs and Q₁₀ to manipulated aboveground and belowground litter alterations. We found that 100% aboveground litter addition (double litter) increased Rs by 26.1% (95% confident intervals, 18.4%–33.7%), whereas 100% aboveground litter removal, root removal and litter + root removal reduced Rs by 22.8% (18.5%–27.1%), 34.1% (27.2%–40.9%) and 43.4% (36.6%–50.2%) respectively. Moreover, the effects of aboveground double litter and litter removal on Rs increased with experimental duration, but not those of root removal. Aboveground litter removal marginally increased Q₁₀ by 6.2% (0.2%–12.3%) because of the higher temperature sensitivity of stable C substrate than fresh litter. Estimated from the studies that simultaneously tested the responses of Rs to aboveground litter addition and removal and assuming negligible changes in root‐derived Rs, “priming effect” on average accounted for 7.3% (0.6%–14.0%) of Rs and increased over time. Across the global variation in terrestrial ecosystems, the effects of aboveground litter removal, root removal, litter + root removal on Rs as well as the positive effect of litter removal on Q₁₀ increased with water availability. Our meta‐analysis indicates that priming effects should be considered in predicting Rs to climate change‐induced increases in litterfall. Our analysis also highlights the need to incorporate spatial climate gradient in projecting long‐term Rs responses to litter alterations.     

Improvement of both lipid and biomass productivities of Qatar Chlorocystis isolate for biodiesel production and food security

Microalgae are considered a very promising alternative for biofuel production. Several strategies were developed to modulate and improve algae metabolites production to meet the requirements for biodiesel production. Most previous research evidenced that the increase of the lipid content is accompanied by a decrease of the biomass production, which increases the cost of the downstream processing. Hence, the challenge is to find special culture conditions that increase the lipid and the biomass productivities simultaneously. In the present work, we developed a strategy for the improvement of biomass and lipid productivities in a novel local microalga isolate, Chlorocystis sp. QUCCCM14, which was not previously known as a promising strain. Indeed, culturing QUCCCM14 using f/2 medium with 10× NaH₂PO₄ (0.15 g L^?1 NaNO₃ and 5.6 mg L^?1 NaH₂PO₄) resulted in an improvement of 3.178 folds the lipid productivity reaching 56.121 mg L^?1 day^?1 and enhanced the biomass productivity reaching 141.363 mg L^?1 day^?1, simultaneously. Comparative analyses of the FAME profiles demonstrated that fed‐batch culture with phosphate or nitrate separately leads to a high production of the omega 3 fatty acids (Linolenic acid), whereas fed‐batch culture with phosphate and nitrate simultaneously increased the production of fatty acids suitable for biodiesel production.     

糖皮质激素联合吗替麦考酚酯分散片对系统性红斑狼疮患者的疗效及对免疫功能的影响

目的:研究糖皮质激素联合吗替麦考酚酯分散片治疗系统性红斑狼疮患者的临床疗效及对免疫功能的影响。方法:选取2014年9月至2015年8月本院收治的84例系统性红斑狼疮患者,根据投硬币法分为观察组和对照组,42例每组。对照组使用单纯的糖皮质激素,观察组在此基础上使用吗替麦考酚酯分散片。比较两组患者临床疗效,治疗前后免疫球蛋白A(IgA)、免疫球蛋白(IgG)、免疫球蛋白(IgM)、C反应蛋白(CRP)、血沉(ESR)的变化及不良反应的发生情况。结果:治疗后,观察组临床总有效率显著高于对照组(P0.05)。治疗前,两组患免疫球蛋白A(IgA)、免疫球蛋白(IgG)、免疫球蛋白(IgM)、C反应蛋白(CRP)、血沉(ESR)水平比较差异均无统计学意义(P0.05);治疗后,两组患者IgA、IgG、IgM、CRP、ESR水平均较治疗前显著降低(P0.05),与对照相比,观察组的IgA、IgG、IgM、CRP、ESR明显降低(P0.05)。两组组的不良反应率比较差异无统计学意义(P0.05)。结论:糖皮质激素联合吗替麦考酚酯分散片能有效改善系统性红斑狼疮患者的免疫功能,临床疗效良好,安全性高。     

Timing of precipitation in an arid environment: Effects on population performance of a large herbivore

Climate models predict that shifts in temperature and precipitation patterns are likely to occur across the globe. Changing climate will likely have strong effects on arid environments as a result of increased temperatures, increasing frequency and intensity of droughts, and less consistent pulses of rainfall. Therefore, understanding the link between patterns of precipitation, temperature, and population performance of species occupying these environments will continue to increase in importance as climatic shifts occur within these natural ecosystems. We sought to evaluate how individual, maternal, population, and environmental, particularly temperature and precipitation, level factors influence population performance of a large herbivore in an arid environment. We used mule deer (Odocoileus hemionus) as a representative species and quantified juvenile survival to test hypotheses about effects of environmental factors on population performance. Precipitation events occurring in mid‐ to late‐pregnancy (January–April) leading to spring green‐up, as indexed by normalized difference in vegetation index, had the strongest positive effect on juvenile survival and recruitment. In addition, larger neonates had an increased probability of survival. Our findings indicate that timing and amount of precipitation prior to parturition have strong influences on maternal nutritional condition, which was passed on to young. These results have important implications for understanding how animal populations may benefit from timing of precipitation during spring and prior to parturition, especially in arid environments.     

不同产地‘金圆’猕猴桃低温贮藏下的生理指标及贮藏性变化

以中华猕猴桃(Actinidia chinensis Planch.)黄肉新品种‘金圆’果实为材料,通过低温贮藏实验(1℃±0.5℃,相对湿度90%~95%),系统研究武汉和六盘水所产‘金圆’果实的生理指标及贮藏性。结果显示,两地‘金圆’果实硬度和色彩角(h值)随贮藏时间延长而逐渐下降,硬度在前20 d下降幅度大。果实可溶性固形物(SSC)含量和干物质在贮藏期间变化规律基本一致,六盘水产果实的SSC和干物质含量高于武汉。武汉产果实VC、可溶性总糖、可滴定酸含量仅在80 d时高于六盘水,其他时间均低于六盘水。两地果实的固酸比和糖酸比变化一致,六盘水产果实固酸比(SSC/TA)和糖酸比(SS/TA)在80 d时均达到峰值,而武汉产果实只有糖酸比达到峰值。随贮藏时间延长,两地果实的失重率均缓慢上升,160 d时武汉和六盘水果实的失重率分别为2.82%和2.55%;在贮藏前60 d两地果实腐烂率较低,之后上升较快,160 d时六盘水产果实腐烂率是武汉的1.77倍。本研究结果表明六盘水产‘金圆’果实的风味品质优于武汉,而武汉产果实贮藏性更好些。     

Serum circulating cell free DNA as potential diagnostic and prognostic biomarker in non small cell lung cancer

BackgroundNon-small cell lung cancer (NSCLC) is leading cause of cancer related death and the survival rate for patients with NSCLC remain poor so early diagnosis of NSCLC represents the best opportunity for cure. Cell-free DNA (cf-DNA) is extracellular nucleic acids found in cell-free plasma/serum of humans, given the recent approval of a liquid biopsy in lung cancer, the use of circulating tumor DNA as a novel non-invasive diagnostic and prognostic biomarker is promising.ObjectivesStudying whether the concentrations of circulating Cell Free DNA in serum can be used as a diagnostic and prognostic biomarker for NSCLC patients.MethodThis study was carried out on 140 subjects included 60 patients with non small cell lung cancer,40 patients with Chronic Obstructive Pulmonary Disease (COPD) and 40 healthy controls. Quantitative analysis of serum circulating cf-DNA was done b y AlU-based quantitative real time PCR. Serum level of CEA was measured by ELISA.ResultsNSCLC patients demonstrated significantly higher values of each of ALU 215, ALU 247, and DNA integrity than both COPD patients and controls. On ROC curve analysis, the total accuracy of ALU 247, ALU 115, DNA integrity (92.1%, 83.6%, 56.4%) at cutoff points (325, 565 & 0.48) respectively. On combining both DNA integrity and CEA, improved sensitivity to 93.3% was noted. For NSCLC patients, ALU 115 & ALU 247 increased significantly with more advanced stage and highest level was noticed in metastatic patients. Regarding survival there was better overall survival among patients with low DNA integrity.ConclusionSerum cf-DNA concentrations and integrity index may be valuable tool in early diagnosis of NSCLC and prediction of prognosis of those patients.     

The evolution of deepwater dissolved oxygen in the northern South China Sea since 400 ka

The dissolved oxygen (DO) content of the ocean provides potential evidence and clues for the waxing and waning of marine productivity, ocean circulation, global climate change, and the evolution of ecological communities. On the basis of the analysis of the Benthic Foraminiferal Oxygen Index (BFOI), the percentage of epifaunal benthic foraminifers, and the redox-sensitive trace elements (Mo/Al) in Core MD12-3432, we reconstruct the evolution of deep water DO content in the northern South China Sea (SCS) during the past 400 ka and discuss the mechanisms of variable DO content. The results show that the changes of BFOI, Mo/Al, and the percentage of epifaunal benthic foraminifer present a similar pattern, which may reflect the variations of the DO content in seawater since 400 ka. Both variations in BFOI and Mo/Al indicate that the DO content was high during most time of marine isotope stage (MIS) 11 to mid-MIS 6, then decreased in late-MIS 6, and remained stable in MIS 5. It increased in MIS 4 and decreased until MIS 2, and then rose again. The non-synchronous variations between bottom water DO and benthic foraminiferal δ¹⁸O indicate that the DO content is not controlled by glacial-interglacial cyclic environmental variations. Comparing the biomarker productivity index with the DO content of water, we find that the DO content is affected mainly by productivity. Bulimina, Uvigerina and Chilostomella oolina are high productivity species. The accumulation rates of Bulimina and Uvigerina are higher during 61–15 kyr interval, but the accumulation rate of C. oolina is higher during 168–130 kyr. The results infer that different intensity of primary productivity and DO during these two periods. The DO and phytoplankton total (PT) show the opposite relation, which also indicates that the DO is affected by primary productivity, and the combined action of productivity and DO decides the growth of Bulimina, Uvigerina, and C. oolina. Besides the influences of productivity, the change of DO in the ocean is also affected by oceanic circulation.