RESUMEN
The vegetation ecosystem in the southern hilly region of China (SHRC) plays a crucial role in the country's carbon reservoir. Clarifying the dynamics of net primary productivity (NPP) in this area and its response to climate factors in the context of climate change is important for national forest ecology, management, and carbon neutrality efforts. This study, based on remote sensing and meteorological data spanning the period 2001 to 2021, aims to unveil the spatiotemporal patterns of vegetation productivity and climate factors in the southern hilly region, explore interannual variation characteristics of vegetation productivity with altitude, and investigate the response characteristics of NPP to various climate factors. The results indicate that from 2001 to 2021, the annual average NPP in the southern hilly region had a significant increasing trend of 2.13 ± 0.78 g m-2 a-1. The trend of NPP varies significantly with altitude. Despite a general substantial upward trend in vegetation NPP, regions at lower elevations exhibit a faster rate of increase, suggesting a diminishing difference in the NPP of different elevation ranges. The overall rise in average temperature has positive implications for the southern hilly region, while the impact of precipitation on vegetation NPP demonstrates noticeable spatial heterogeneity. Regions in which vegetation NPP is significantly negatively correlated with precipitation are mainly concentrated in the southern areas of Guangdong, Fujian, and Jiangxi provinces. In contrast, other regions further away from the southeastern coast tend to exhibit a positive correlation. Over the past two decades, there has been an asymmetry in the diurnal temperature variation in the SHRC, with the nighttime warming rate being 1.8 times that of the daytime warming rate. The positive impact of daytime warming on NPP of vegetation is more pronounced than the impact of nighttime temperature changes. Understanding the spatiotemporal patterns of NPP in the SHRC and the characteristics of its response to climate factors contributes to enhancing our ability to protect and manage vegetation resources amidst the challenges of global climate change.
RESUMEN
Ultrafast fiber lasers combining high peak power and excellent beam quality in the 1-µm wavelength range have been explored to applications in industry, medicine and fundamental science. Here, we report generation of a high-energy sub 300 fs polarization maintaining fiber chirped pulse amplification (CPA) system by using a Yb-doped large mode area tapered polarization maintaining (PM) optical fiber with the core/cladding diameters of 35/250 µm at the thin end and 56/400 µm at the thick end. The taper fiber design features a confined core for selective gain amplification and multi-layer cladding for enhanced suppression of higher order modes. In this regime, we have demonstrated 266 fs pulse amplification with peak power of up to 132 MW at a repetition rate of 2 MHz and high beam quality with measured M2 value of 1.1â¼1.3. To the best of our knowledge, it is the highest peak power reported in such tapered Yb-doped fiber (T-YDF) amplifier in the femtosecond regime. This work indicates the great potential of the T-YDF to realize further power scaling, high laser efficiency, and excellent beam quality in high-power femtosecond fiber lasers.
RESUMEN
BACKGROUND: Pancreatic cancer ranks as the fourth leading cause of cancer-related mortality in the USA. And gemcitabine has been the standard of care for advanced pancreatic cancer. However, a combined use of gemcitabine plus cisplatin (GemCis) has shown promising efficacies in pancreatic cancer patients. Here, system review and meta-analysis were performed to compare the efficacy and safety of GemCis versus gemcitabine (Gem) alone in the treatment of pancreatic cancer. METHODS: The databases of MEDLINE (PubMed), EMBASE, and Cochrane Library were systematically searched for retrieving the relevant publications prior to 31 September 2014. The primary end point was overall survival (OS) and secondary end points included 6-month survival, 1 year survival, overall response rate (ORR), clinical benefit rate (CBR), time to progression/progression-free survival (TTP/PFS), and toxicities. RESULTS: A total of nine randomized controlled trials involving 1354 patients were included for systematic evaluations. Overall, as compared with Gem alone, GemCis significantly improved the 6-month survival rate (relative risk (RR) = 1.303, 95% confidence interval (CI) 1.090-1.558, P = 0.004), ORR (RR = 1.482, 95% CI 1.148-1.913, P = 0.003), PFS/TTP (hazard ratio (HR) = 0.87; 95% CI 0.78-0.93, P = 0.022), and the overall toxicities (RR = 2.164, 95% CI 1.837-2.549, P = 0.000). However, no significance difference existed in overall survival (HR = 0.90, 95% CI 0.80-1.42, P = 1.02), 1-year survival rate (RR = 0.956, 95% CI 0.770-1.187, P = 0.684), and CBR (RR = 0.854, 95% CI 0.681-1.072, P = 0.175). As for grade III/IV toxicity, seven kinds of toxicities were higher in the GemCis group. However, no significant inter-group statistical differences existed in the incidence of leukopenia, thrombocytopenia, or diarrhea. CONCLUSIONS: Despite a higher incidence of three-fourths toxicity, GemCis offers better outcomes of ORR, PFS/TTP, and 6-month survival, which indicates GemCis may be a promising therapy for pancreatic cancer.
