Nutrient co‐limitation in the subtropical Northwest Pacific

Nutrients limiting phytoplankton growth in the ocean are a critical control on ocean productivity and can underpin predicted responses to climate change. The extensive western subtropical North Pacific is assumed to be under strong nitrogen limitation, but this is not well supported by experimental evidence. Here, we report the results of 14 factorial nitrogen–phosphorus–iron addition experiments through the Philippine Sea, which demonstrate a gradient from nitrogen limitation in the north to nitrogen–iron co-limitation in the south. While nitrogen limited sites responded weakly to nutrient supply, co-limited sites bloomed with up to ~60-fold increases in chlorophyll a biomass that was dominated by initially undetectable diatoms. The transition in limiting nutrients and phytoplankton growth capacity was driven by a gradient in deep water nutrient supply, which was undetectable in surface concentration fields. We hypothesize that this large-scale phytoplankton response gradient is both climate sensitive and potentially important for regulating the distribution of predatory fish

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Carbon emission quantification and reduction in pavement use phase: A review

The carbon emissions arising from road pavement infrastructures have emerged as critical issue in recent years. The life cycle of a pavement can be divided into five phases, namely raw materials and production, construction, use, maintenance and end of life. While the use phase generates the highest carbon emissions throughout the pavement's life cycle, it is usually neglected in most pavement life cycle assessment (LCA) studies due to its complexity and uncertainty. Therefore, this review selected 126 relevant references, focuses on quantification methods, influential factors and reduction technologies of carbon emissions in pavement use phase. Among the carbon accounting approached, the LCA approach, remains the most widely used for evaluating the environmental impact of pavements. Second, the primary influential factors on the use phase' carbon emission include pavement-vehicle interaction primarily affected by pavement roughness, pavement albedo and climate change. Most influential factors above indirectly cause changes in carbon emissions by influencing the pavement performance and subsequent vehicle emissions. Finally, the review surveys carbon emission reduction technologies during pavement use phase, focusing mainly on reducing pavement rolling resistance and constructing cool pavements. Reflective pavements and permeable pavements are the most widely used cool pavement technologies. Overall, the aspects involved in this paper hold significant promise for quantifying and reducing carbon emissions in the pavement use phase

The effect of periodic resistance training on obese patients with type 2 diabetic nephropathy

Abstract Resistance training is an exercise against resistance designed to train the endurance and strength of muscle. To observe the effect of intervention of periodic resistance training on obese patients with type 2 diabetic nephropathy. A total of 60 obese patients with type 2 diabetic nephropathy were randomized into resistance training group and aerobic exercise group (30 patients each group) for observing the changes of blood glucose, body weight, blood lipid, insulin resistance, serum creatinine (Scr), urinary microalbumin, urinary albumin excretion rate (UAER) calculated by urinary creatinine, and glomerular filtration rate (GFR) after 12 weeks of intervention, and relevant significance as well. The number of patients with hypoglycemia during the intervention was also recorded. After 12 weeks of intervention, the weight, Body mass index (BMI), Waist, Triglyceride (TG), Cholesterol (TC), Low-density lipoprotein cholesterol (LDL), Fasting glucose (FBG), Fasting insulin (FINS), Glycosylated hemoglobin (HbA1c) and urine Albumin–Creatinine Ratio (uACR) were decreased and GFR was increased in both groups (P  0.05). Periodic resistance training can not only control the weight, blood sugar and blood lipid of obese patients with type 2 diabetic nephropathy, but also improve the urinary albumin excretion rate and glomerular filtration rate of early obese patients with type 2 diabetic nephropathy, and delay the progression of diabetic nephropathy. It is an effective non-drug intervention

Single-parameter mechanical design of a 3D-printed octet truss topological scaffold to match natural cancellous bones

Designing a suitable scaffold matching the mechanical properties of natural bones to optimize the bone regeneration is required in bone tissue engineering. The present work developed a single-parameter design method for the octet truss topological scaffold to achieve the accurate prediction and flexible adjustment of its Young's modulus and strength. A theoretical model that formulated the normalized Young's modulus and normalized yield strength of the octet truss scaffold by the single parameter (d/Ø) was proposed and further validated by uniaxial compression tests and FEA simulations. On the basis of the proposed model, the Young's modulus and yield strength of the octet truss scaffold made of different polymers with different d/Ø were mapped, and the ranges of suitable d/Ø that match the different natural cancellous bones were suggested. The results showed that the design method could accurately predict the porosity, specific area, normalized Young's modulus and normalized yield strength, and adjust the mechanical properties of the scaffold in a wide range. The present work can be used for the design of scaffolds and the selection of constituent materials to obtain a suitable scaffold with desired mechanical properties, and has application prospects in the fields of bone tissue engineering and regenerative medicine.</p

Study on Salt Dissolution Law of High Salinity Reservoir and Its Influence on Fracturing

For the high-salt reservoir of the Fengcheng Formation in the Mahu area, the production decreases rapidly due to the conductivity decrease after fracturing. The analysis shows that this has a great relationship with the special salt dissolution characteristics of the High salinity reservoir. In order to study the problem of salt dissolution pattern, the effect of different temperatures, the salt concentration of fracturing fluid, the viscosity of fracturing fluid, and injection rate on the rate of salt dissolution was evaluated by using the dynamic experimental evaluation method of salt dissolution. Through the grey correlation analysis of salt rock dissolution rate, it can be found that the degree of influence is from large to small which the influence of temperature is greater than fracturing fluid velocity, followed by fracturing fluid viscosity and, finally, fracturing fluid salt concentration. The results of compressive strength tests on salt-bearing rocks after dissolution show that the compressive strength is greatly reduced after salt dissolution by more than 60%. At the same time, the test results of proppant-free conductivity showed that the conductivity increased first and then decreased sharply after salt dissolution. This shows that in the early stage of salt dissolution, the flow channel will increase through dissolution. The rock strength decreases greatly with the increase of salt dissolution. As a result, collapse leads to a sharp reduction in the facture conductivity. Therefore, it is necessary to choose saturated brine fracturing fluid. In the proppant conductivity experiments, by optimizing the use of saturated brine fracturing fluid with 30/50 mesh or 20/40 mesh ceramic proppant with a sand concentration of 5 Kg/m2, a high facture conductivity can be achieved under high closure pressure conditions. Based on the above study, directions and countermeasures for improving high saline reservoirs are proposed, which point the way to improve the fracturing conductivity

Study on Salt Dissolution Law of High Salinity Reservoir and Its Influence on Fracturing

For the high-salt reservoir of the Fengcheng Formation in the Mahu area, the production decreases rapidly due to the conductivity decrease after fracturing. The analysis shows that this has a great relationship with the special salt dissolution characteristics of the High salinity reservoir. In order to study the problem of salt dissolution pattern, the effect of different temperatures, the salt concentration of fracturing fluid, the viscosity of fracturing fluid, and injection rate on the rate of salt dissolution was evaluated by using the dynamic experimental evaluation method of salt dissolution. Through the grey correlation analysis of salt rock dissolution rate, it can be found that the degree of influence is from large to small which the influence of temperature is greater than fracturing fluid velocity, followed by fracturing fluid viscosity and, finally, fracturing fluid salt concentration. The results of compressive strength tests on salt-bearing rocks after dissolution show that the compressive strength is greatly reduced after salt dissolution by more than 60%. At the same time, the test results of proppant-free conductivity showed that the conductivity increased first and then decreased sharply after salt dissolution. This shows that in the early stage of salt dissolution, the flow channel will increase through dissolution. The rock strength decreases greatly with the increase of salt dissolution. As a result, collapse leads to a sharp reduction in the facture conductivity. Therefore, it is necessary to choose saturated brine fracturing fluid. In the proppant conductivity experiments, by optimizing the use of saturated brine fracturing fluid with 30/50 mesh or 20/40 mesh ceramic proppant with a sand concentration of 5 Kg/m2, a high facture conductivity can be achieved under high closure pressure conditions. Based on the above study, directions and countermeasures for improving high saline reservoirs are proposed, which point the way to improve the fracturing conductivity