353 research outputs found

    Simulation study on giant panda population dynamics model with due consideration for deforestation

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    AbstractDeforestation has destroyed the home of giant panda and poses a direct threat to their survival. Based on the idea of habitat protection of the trinity of “forest-bamboo-giant panda”, a “forest-bamboo-giant panda” nonlinear dynamics model is established with due consideration for pulse deforestation. Computer numerical simulation is used to study the periodic solutions of this dynamics model and chaos strange attractor, and the ecological significance of the dynamic results. A threshold value in deforestation is thus obtained. That is, when the pulse intensity of deforestation is beyond a given threshold, the giant panda population will be almost extinct even though some forest still remains. When the pulse intensity of deforestation is within a given threshold, an ecological balance among “Forest-bamboo-giant panda” will kept for them to continue to exist

    Mapping QTLs for mineral accumulation and shoot dry biomass under different Zn nutritional conditions in Chinese cabbage ( Brassica rapa L. ssp. pekinensis )

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    Abstract Chinese cabbage (Brassica rapa L. ssp. pekinensis) is one of the most important vegetables in China. Genetic dissection of leaf mineral accumulation and tolerance to Zn stress is important for the improvement of the nutritional quality of Chinese cabbage by breeding. A mapping population with 183 doubled haploid (DH) lines was used to study the genetics of mineral accumulation and the growth response to Zn. The genetic map was constructed based on 203 AFLPs, 58 SSRs, 22 SRAPs and four ESTPs. The concentration of 11 minerals was determined in leaves for 142 DH lines grown in an open field. In addition shoot dry biomass (SDB) under normal, deficient and excessive Zn nutritional conditions were investigated in hydroponics experiments. Ten QTLs, each explaining 11.1Âż17.1% of the Na, Mg, P, Al, Fe, Mn, Zn and Sr concentration variance, were identified by multiple-QTL model (MQM) mapping. One common QTL was found affecting SDB under normal, deficient and excessive Zn nutritional conditions. An additional QTL was detected for SDB under Zn excess stress only. These results offer insights into the genetic basis of leaf mineral accumulation and plant growth under Zn stress conditions in Chinese cabbag

    The dissipative dynamics of the field of two-photon Jaynes-Cummings model with Stark shift in dispersive approximation

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    We present the dissipative dynamics of the field of two-photon Jaynes-Cummings model (JCM) with Stark shift in dispersive approximation and investigate the influence of dissipation on entanglement. We show the coherence properties of the field can be affected by the dissipative cavity when nonlinear two-photon process is involved.Comment: 8 pages,3 figure

    Characteristics of the grain-filling process and starch accumulation of high-yield common buckwheat ‘cv. Fengtian 1’ and tartary buckwheat ‘cv. Jingqiao 2’

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    High-yield common buckwheat ‘cv. Fengtian 1’ (FT1) and tartary buckwheat ‘cv. Jingqiao 2’ (JQ2) were selected to investigate the characteristics of the grain-filling process and starch accumulation of high-yield buckwheat. FT1 had an average yield that was 43.0% higher than that of the control ‘cv. Tongliaobendixiaoli’ (TLBDXL) in two growing seasons, while JQ2 had an average yield that was 27.3% higher than that of the control ‘cv. Chuanqiao 2’ (CQ2). The Richards equation was utilized to evaluate the grain-filling process of buckwheat. Both FT1 and JQ2 showed higher values of initial growth power and final grain weight and longer linear increase phase, compared with respective control. These values suggest that the higher initial increasing rate and the longer active growth period during grain filling play important roles to increase buckwheat yield. Similar patterns of starch, amylose and amylopectin accumulation were detected in common buckwheat, leading to similar concentration of each constituent at maturity in FT1 and TLBDXL. Tartary buckwheat showed an increasing accumulation pattern of amylose in developing seeds, which differed from that of starch and amylopectin. This pattern led to a significant difference of the concentrations of amylose and amylopectin at maturity between JQ2 and CQ2, the mechanisms of which remained unclear. Nevertheless, both FT1 and JQ2 showed increased starch, amylose, and amylopectin accumulation during the physiological maturity of grains. The results suggest that prolonging the active grain-filling period to increase carbohydrate partitioning from source to seed sink can be an effective strategy to improve buckwheat yield

    Contribution of biomimetic collagen-ligand interaction to intrafibrillar mineralization

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    Contemporary models of intrafibrillar mineralization mechanisms are established using collagen fibrils as templates without considering the contribution from collagen-bound apatite nucleation inhibitors. However, collagen matrices destined for mineralization in vertebrates contain bound matrix proteins for intrafibrillar mineralization. Negatively charged, high\u2013molecular weight polycarboxylic acid is cross-linked to reconstituted collagen to create a model for examining the contribution of collagen-ligand interaction to intrafibrillar mineralization. Cryogenic electron microscopy and molecular dynamics simulation show that, after cross-linking to collagen, the bound polyelectrolyte caches prenucleation cluster singlets into chain-like aggregates along the fibrillar surface to increase the pool of mineralization precursors available for intrafibrillar mineralization. Higher-quality mineralized scaffolds with better biomechanical properties are achieved compared with mineralization of unmodified scaffolds in polyelectrolyte-stabilized mineralization solution. Collagen-ligand interaction provides insights on the genesis of heterogeneously mineralized tissues and the potential causes of ectopic calcification in nonmineralized body tissues

    Rms-flux relation of Cyg X-1 with RXTE: dipping and nondipping cases

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    The rms (root mean square) variability is the parameter for understanding the emission temporal properties of X-ray binaries (XRBs) and active galactic nuclei (AGN). The rms-flux relation with Rossi X-ray Timing Explorer (RXTE) data for the dips and nondip of black hole Cyg X-1 has been investigated in this paper. Our results show that there exist the linear rms-flux relations in the frequency range 0.1-10 Hz for the dipping light curve. Moreover, this linear relation still remains during the nondip regime, but with the steeper slope than that of the dipping case in the low energy band. For the high energy band, the slopes of the dipping and nondipping cases are hardly constant within errors. The explanations of the results have been made by means of the ``Propagating Perturbation'' model of Lyubarskii (1997).Comment: 15 pages, 12 figures, Accepted for publication in Astrophysics & Space Scienc

    Microspore Abortion and Abnormal Tapetal Degeneration in BNS Thermo-sensitive Male Sterile Wheat Lines

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    Studies of the pollen abortion mechanism in thermo-sensitive male sterile lines may provide a strong foundation for breeding hybrid wheat and establishing a theoretical basis for marker-assisted selection. To investigate the cause of pollen abortion in Bainong thermo – sensitive male sterile (BNS) lines, we analyzed the properties of pollen grains, changes in the tapetum and microspores in different anther developmental stages, and the distribution and deposition of nutrient substances in microspores. We found that tapetum degraded in the early uninucleate stage in sterile BNS (S-BNS), which was earlier than that of fertile BNS (F-BNS) tapetum. Large amounts of insoluble polysaccharides, lipids, and proteins were deposited until the trinucleate pollen stage in the nutritive cells in F-BNS. At the binucleate stage, the vacuoles disappeared and pollen inclusion increased gradually. At the trinucleate stage, these nutrients would help pollen grains mature and participate in fertilization normally. Therefore, early degradation of the tapetum, which inhibits normal microspore development, and the limited content of nutrient substances in pollen may be the main factors responsible for male sterility in BNS lines

    State sampling dependence of the Hopfield network inference

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    The fully connected Hopfield network is inferred based on observed magnetizations and pairwise correlations. We present the system in the glassy phase with low temperature and high memory load. We find that the inference error is very sensitive to the form of state sampling. When a single state is sampled to compute magnetizations and correlations, the inference error is almost indistinguishable irrespective of the sampled state. However, the error can be greatly reduced if the data is collected with state transitions. Our result holds for different disorder samples and accounts for the previously observed large fluctuations of inference error at low temperatures.Comment: 4 pages, 1 figure, further discussions added and relevant references adde

    Efficacy and safety of upadacitinib for active ankylosing spondylitis refractory to biological therapy: a double-blind, randomised, placebo-controlled phase 3 trial

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    Objectives: To evaluate the efficacy and safety of upadacitinib, a Janus kinase inhibitor, in patients with active ankylosing spondylitis (AS) with an inadequate response (IR) to biological disease-modifying antirheumatic drugs (bDMARDs). Methods: Adults with active AS who met modified New York criteria and had an IR to one or two bDMARDs (tumour necrosis factor or interleukin-17 inhibitors) were randomised 1:1 to oral upadacitinib 15 mg once daily or placebo. The primary endpoint was Assessment of SpondyloArthritis international Society 40 (ASAS40) response at week 14. Sequentially tested secondary endpoints included Ankylosing Spondylitis Disease Activity score, Spondyloarthritis Research Consortium of Canada MRI spine inflammation score, total back pain, nocturnal back pain, Bath Ankylosing Spondylitis Functional Index, Bath Ankylosing Spondylitis Metrology Index and Maastricht Ankylosing Spondylitis Enthesitis Score. Results are reported from the 14-week double-blind treatment period. Results: A total of 420 patients with active AS were randomised (upadacitinib 15 mg, n=211; placebo, n=209). Significantly more patients achieved the primary endpoint of ASAS40 at week 14 with upadacitinib vs placebo (45% vs 18%; p<0.0001). Statistically significant improvements were observed with upadacitinib vs placebo for all multiplicity-controlled secondary endpoints (p<0.0001). Adverse events were reported for 41% of upadacitinib-treated and 37% of placebo-treated patients through week 14. No events of malignancy, major adverse cardiovascular events, venous thromboembolism or deaths were reported with upadacitinib. Conclusion: Upadacitinib 15 mg was significantly more effective than placebo over 14 weeks of treatment in bDMARD-IR patients with active AS. No new safety risks were identified with upadacitinib.</p

    Safety and efficacy of upadacitinib in patients with active ankylosing spondylitis and an inadequate response to nonsteroidal antiinflammatory drug therapy: one-year results of a double-blind, placebo-controlled study and open-label extension

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    Objective To report the efficacy and safety of upadacitinib through 1 year in patients with ankylosing spondylitis (AS). Methods In the SELECT-AXIS 1 study, adults with active AS and an inadequate response to nonsteroidal antiinflammatory drugs were randomized to receive upadacitinib 15 mg once daily or placebo. At week 14, patients who had been randomized to receive placebo were switched to upadacitinib, and all patients continued in the open-label extension and received upadacitinib up to week 104; interim data up to week 64 are reported herein. Results Of 187 patients, 178 completed week 14 on study drug and entered the open-label extension. Similar proportions of patients in either group (continuous upadacitinib or placebo-to-upadacitinib) achieved Assessment of SpondyloArthritis international Society 40% response (ASAS40) or Ankylosing Spondylitis Disease Activity Score (ASDAS) showing low disease activity at week 64: >= 70% of patients achieved these end points based on nonresponder imputation (NRI) and >= 81% based on as-observed analyses. Furthermore, >= 34% (NRI) and >= 39% (as-observed analysis) achieved ASDAS showing inactive disease or ASAS showing partial remission at week 64. Mean changes from baseline (week 0) to week 64 in pain, function, and inflammation showed consistent improvement or sustained maintenance through the study. Among 182 patients receiving upadacitinib (237.6 patient-years), 618 adverse events (260.1 per 100 patient-years) were reported. No serious infections, major adverse cardiovascular events, venous thromboembolic events, gastrointestinal perforation, or deaths were reported. Conclusion Upadacitinib 15 mg once daily showed sustained and consistent efficacy over 1 year. Patients who switched from placebo to upadacitinib at week 14 showed similar efficacy versus those who received continuous upadacitinib.Pathophysiology and treatment of rheumatic disease
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