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We hypothesize that phytoplankton have the sequential nutrient uptake strategy to maintain nutrient stoichiometry and high primary productivity in the water column. According to this hypothesis, phytoplankton take up the most limiting nutrient first until depletion, continue to draw down non-limiting nutrients and then take up the most limiting nutrient rapidly when it is available. These processes would result in the variation of ambient nutrient ratios in the water column around the Redfield ratio. We used high-resolution continuous vertical profiles of nutrients, nutrient ratios and on-board ship incubation experiments to test this hypothesis in the Strait of Georgia. At the surface in summer, ambient NO3− was depleted with excess PO43− and SiO4− remaining, and as a result, both N : P and N : Si ratios were low. The two ratios increased to about 10 : 1 and 0. 45 : 1, respectively, at 20 m. Time series of vertical profiles showed that the leftover PO43− continued to be removed, resulting in additional phosphorus storage by phytoplankton. The N : P ratios at the nutricline in vertical profiles responded differently to mixing events. Field incubation of seawater samples also demonstrated the sequential uptake of NO3− (the most limiting nutrient) and then PO43− and SiO4− (the non-limiting nutrients). This sequential uptake strategy allows phytoplankton to acquire additional cellular phosphorus and silicon when they are available and wait for nitrogen to become available through frequent mixing of NO3− (or pulsed regenerated NH4). Thus, phytoplankton are able to maintain high productivity and balance nutrient stoichiometry by taking advantage of vigorous mixing regimes with the capacity of the stoichiometric plasticity. To our knowledge, this is the first study to show the in situ dynamics of continuous vertical profiles of N : P and N : Si ratios, which can provide insight into the in situ dynamics of nutrient stoichiometry in the water column and the inference of the transient status of phytoplankton nutrient stoichiometry in the coastal ocean.

Background : The prevalence of chronic rhinitis is increasing rapidly; its pathogenesis is to be further understood; immune inflammation is one of the possible causative factors. Antigen specific CD8+ T cells play a critical role in the induction of chronic inflammation. Aims : This study aimed to investigate the role of antigen specific CD8+ T cells in the pathogenesis of chronic atypical allergic rhinitis. Material and Methods : Nasal mucosal epithelial surface scratching samples were obtained from patients with chronic obstruction atypical allergic rhinitis. Exosomes were purified from the scratching samples and examined by immune gold electron microscopy. The effect of exosomes on modulating dendritic cell's properties, the effect of exosome-pulsed dendritic cells on naive T cell differentiation and the antigen specific CD8+ T cell activation were observed by cell culture models. Results : Exosomes purified from patients with chronic atypical allergic rhinitis carried microbial products, Staphylococcal enterotoxin B (SEB), and airborne antigen, Derp1. Dendritic cells pulsed by SEB/Derp1-carrying exosomes showed high levels of CD80, CD86 and the major histocompatibility class I (MHCI). Exosome-pulsed dendritic cells could induce the naive CD3+ T cells to differentiate into CD8+ T cells. Upon the exposure to a specific antigen, the CD8+ T cells released granzyme B and perforin; more than 30% antigen specific CD8+ T cells proliferated. Conclusions : Antigen specific CD8+ T cells play an important role in the pathogenesis of chronic obstruction atypical allergic rhinitis.

This paper concerns reinforcement learning~(RL) of the document ranking models for information retrieval~(IR). One branch of the RL approaches to ranking formalize the process of ranking with Markov decision process~(MDP) and determine the model parameters with policy gradient. Though preliminary success has been shown, these approaches are still far from achieving their full potentials. Existing policy gradient methods directly utilize the absolute performance scores (returns) of the sampled document lists in its gradient estimations, which may cause two limitations: 1) fail to reflect the relative goodness of documents within the same query, which usually is close to the nature of IR ranking; 2) generate high variance gradient estimations, resulting in slow learning speed and low ranking accuracy. To deal with the issues, we propose a novel policy gradient algorithm in which the gradients are determined using pairwise comparisons of two document lists sampled within the same query. The algorithm, referred to as Pairwise Policy Gradient (PPG), repeatedly samples pairs of document lists, estimates the gradients with pairwise comparisons, and finally updates the model parameters. Theoretical analysis shows that PPG makes an unbiased and low variance gradient estimations. Experimental results have demonstrated performance gains over the state-of-the-art baselines in search result diversification and text retrieval.

Abstract In this work, the beneficial effect of carbocation scavenger additives on hardwood pretreatment was revealed by significantly improved biomass saccharification: cellulose hydrolysis yield was increased by over 15% after steam pretreatment of poplar, while that was enhanced by more than 48% after dilute acid pretreatment. Besides, the relative contributions of lignin towards enzyme binding and physical barrier effect for proposed mechanisms were quantified. Results indicated that the addition of carbocation scavenger, 2-naphthol-7-sulfonate, resulted in acid groups incorporation of 62.36 mmol/kg to lignin, which mitigated enzyme non-productive binding. Moreover, enlarged biomass porosity and reduced surface lignin coverage were detected through BET and XPS analysis, respectively, which mostly related to the diminished physical barrier effect of lignin. As a result, the lignin inhibitions were significantly suppressed through the addition of carbocation scavenger, giving rise to significantly improved enzymatic hydrolysis of hardwood.

Abstract Mo improved Ni/Al2O3 catalysts were prepared and characterized, which demonstrated good catalytic performance for thioetherification process of FCC gasoline. The physico-chemical properties of the Ni/Al2O3 catalysts with different amounts of Mo were characterized by physical techniques and were correlated with their catalytic performance. Experimental results showed that bimetal (Mo and Ni) based catalysts displayed superior catalytic performance than mono-metal (Ni) based catalysts. Addition of Mo to Ni catalysts could inhibit the formation of NiAl2O4 crystallites and facilitate the formation of active precursor NiMoO4, contributing to the formation of more active sites during the presulfidation process. The micro-morphology of active species was restructured and the needle-stacks of Ni-Mo-S were observed on the Mo improved catalysts. These structures and properties had important influence on the thioetherification. By optimizing the Mo/Ni atomic ratio, the catalysts with a Mo/Ni atomic ratio of 0.3 had suitable micro-morphologies and properties, exhibiting the best catalytic performance and selectivity for thioetherification.

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3–19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8–144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries. http://purl.org/eprint/status/PeerReviewed published version Article

Four diboron BN-heterocycles bearing two BN units have been synthesized via double lithiation/borylation with the aim to examine their thermal and photoelimination properties. In two of the BN-heterocycles, (BN)2-1 and (BN)2-4, the BN units share the central linker unit, while the other two BN-heterocycles (BN)2-2 and (BN)2-3 are isomers with a benzene ring in the middle of the backbone separating the two chelate units. Only compound (BN)2-3 can thermally and photochemically undergo complete double elimination producing green fluorescent (BN)2-3a due to the highly crowded boron centers. (BN)2-2 can partially convert (∼56%) to (BN)2-2a under 350 nm UV irradiation. (BN)2-1 and (BN)2-4 are either inactive or unstable toward photolysis. The molecular structures and electronic properties of these (BN)2-heterocycles have been investigated experimentally as well as computationally using TD-DFT to further elucidate the origin of differences in optical and electronic properties.

Common variants in 94 loci have been associated with breast cancer including 15 loci with genome-wide significant associations (P<5 × 10−8) with oestrogen receptor (ER)-negative breast cancer and BRCA1-associated breast cancer risk. In this study, to identify new ER-negative susceptibility loci, we performed a meta-analysis of 11 genome-wide association studies (GWAS) consisting of 4,939 ER-negative cases and 14,352 controls, combined with 7,333 ER-negative cases and 42,468 controls and 15,252 BRCA1 mutation carriers genotyped on the iCOGS array. We identify four previously unidentified loci including two loci at 13q22 near KLF5, a 2p23.2 locus near WDR43 and a 2q33 locus near PPIL3 that display genome-wide significant associations with ER-negative breast cancer. In addition, 19 known breast cancer risk loci have genome-wide significant associations and 40 had moderate associations (P<0.05) with ER-negative disease. Using functional and eQTL studies we implicate TRMT61B and WDR43 at 2p23.2 and PPIL3 at 2q33 in ER-negative breast cancer aetiology. All ER-negative loci combined account for ∼11% of familial relative risk for ER-negative disease and may contribute to improved ER-negative and BRCA1 breast cancer risk prediction. B.C.A.C. was funded through a European Community Seventh Framework Programme under grant agreement no 223175 (HEALTH-F2-2009-223175; COGS); Cancer Research UK (C1287/A10118, C1287/A10710, C12292/A11174, C1281/A12014, C5047/A8384, C5047/A15007, C5047/A10692); the National Institutes of Health Specialized Program of Research Excellence (SPORE) in Breast Cancer (CA116201), R01 grants (CA128978, CA176785, CA192393), and Post-Cancer GWAS initiative (1U19 CA148537, 1U19 CA148065 and 1U19 CA148112 - the GAME-ON initiative); the Canadian Institutes of Health Research (CIHR) for the CIHR Team in Familial Risks of Breast Cancer, the Breast Cancer Res. Foundation, and the Ovarian Cancer Research Fund. CIMBA genotyping was supported by National Institutes of Health grant (CA128978); the Department of Defence (W81XWH-10-1-0341); and the Breast Cancer Res. Foundation. CIMBA data management and data analysis were supported by Cancer Research UK grants C12292/A11174 and C1287/A10118. This study made use of data generated by the Wellcome Trust Case Control consortium. Functional studies were supported by the Florida Breast Cancer Foundation. A full description of funding and acknowledgments is provided in Supplementary Note 1.

Abstract Significantly higher efficiencies for 129I measurement by Accelerator Mass Spectrometry (AMS) would be possible if 129I3+ ions could be counted at terminal voltages as low as 1 MV. However, at M/Q = 3, the molecular interference was anticipated to be severe; this has prevented the use of charge 3+ from being adequately considered. Instead, charge 5+ has been used at higher terminal voltages because of the minimal interference. During a recent performance assessment with charge state 3+, a background of 129I/127I ≈ 10−14 was readily obtained and few 86Sr2+ and 43Ca1+ ions were encountered. This surprising result is possibly due to the very low binding energy and consequent poor stability of anions such as CaSr− and Ca 3 - . Some triply charged molecular ions were found in the energy spectrum at lower stripping gas pressure but their interference with the detection of 129I3+ was readily suppressed with the Ar gas stripper operated at normal thickness. It now appears that as long as the prepared AMS samples are of good chemical purity, the molecular fragments can be expected to remain quite low in intensity and readily resolved by the final detector. As a result, charge state 3+ can be used for 129I measurements at lower terminal voltages with higher overall efficiency.

Abstract Air classifier mill (ACM) is widely used in powder coating and mineral comminution process. One of the problems typically presenting in ACM is over-grinding, which leads to high energy consumption and broad particle size distribution (PSD). To decrease the excessive amount of fine particles in the products, 6 configurations of grinding pins with ditches in the impact surface were used in the experiments. The width and depth of ditches varied from 1.35 mm and 1 mm to 4.75 mm and 3 mm, respectively, while the interior angles in the ditches are the same. The particle size and PSD show that the ditches on the grinding pins have significant effect on the D10 values and the particle size span. The deepest and widest ditches (P4) result in largest D10 and smallest span in this study. The D10s of products ground by P4 increase by 24.1% for fine powder (D50 = 25 μm) and 16.0% for coarse powder (D50 = 33 μm), while the span decreases by 6.9% (D50 = 25 μm) and 6.4% (D50 = 33 μm) compared to regular cylindrical pins (PC), respectively. Meanwhile, it is found that the P4 configuration improves the energy utilization efficiency by 7.6% (D50 = 25 μm) and 3.4% (D50 = 33 μm), compared to that of the original PC pins.