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Optimal nonlinear excitation of decadal variability of the North Atlantic thermohaline circulation

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Chinese Journal of Oceanology and Limnology 2013年第6期31卷 1356-1362页

作者：祖子清穆穆 Henk A.dijkstra LASG Institute of Atmospheric PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Ocean Circulation and Wave Institute of OceanologyChinese Academy of Sciences Institute for Marine and Atmospheric Research Utrecht Department of Physics and AstronomyUtrecht University

Nonlinear development of salinity perturbations in the Atlantic thermohaline circulation(THC) is investigated with a three-dimensional ocean circulation model,using the conditional nonlinear optimal perturbation *** results show two types of optimal initial perturbations of sea surface salinity,one associated with freshwater and the other with *** types of perturbations excite decadal variability of the *** the same amplitude of initial perturbation,the decadal variation induced by the freshwater perturbation is much stronger than that by the salinity perturbation,suggesting that the THC is more sensitive to freshwater than salinity *** the amplitude of initial perturbation increases,the decadal variations become stronger for both *** salinity perturbations,recovery time of the THC to return to steady state gradually saturates with increasing amplitude,whereas this recovery time increases remarkably for freshwater perturbations.A nonlinear(advective) feedback between density and velocity anomalies is proposed to explain these characteristics of decadal variability *** results are consistent with previous ones from simple box models,and highlight the importance of nonlinear feedback in decadal THC variability.

关键词： thermohaline circulation decadal variability conditional nonlinear optimal perturbation nonlinear advective feedback

Theoretical Proof and Empirical Confirmation of a Continuous Labeling Method Using Naturally ^13C-Depleted Carbon Dioxide

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Journal of Integrative Plant Biology 2007年第3期49卷 401-407页

作者： Weixin Cheng Feike A. dijkstra Environmental Studies University of California Santa Cruz CA 95064 USA

Continuous Isotope labeling and tracing is often needed to study the transformation, movement, and allocation of carbon in plant-soil systems. However, existing labeling methods have numerous limitations. The present study Introduces a new continuous labeling method using naturally ^13C-depleted CO2. We theoretically proved that a stable level of ^13C-CO2 abundance in a labeling chamber can be maintained by controlling the rate of CO2-free air Injection and the rate of ambient airflow with coupling of automatic control of CO2 concentration using a CO2 analyzer. The theoretical results were tested and confirmed in a 54 day experiment in a plant growth chamber. This new continuous labeling method avoids the use of radioactive ^14C or expensive ^13C-enrlched CO2 required by existing methods and therefore eliminates issues of radiation safety or unaffordable isotope cost, as well as creating new opportunities for short- or long-term labeling experiments under a controlled environment.

关键词： carbon flux CO2 isotope rhizosphere tracers

Application of the Conditional Nonlinear Optimal Perturbation Method to the Predictability Study of the Kuroshio Large Meander

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Advances in Atmospheric Sciences 2012年第1期29卷 118-134页

作者： WANG Qiang MU Mu Henk A.dijkstra State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atomspheric PhysicsChinese Academy of SciencesBeijing 100029 Graduate University of the Chinese Academy of Sciences Beijing 100049 Key Laboratory of Ocean Circulation and Wave Institute of OceanologyChinese Academy of SciencesQingdao 266071 Institute for Marine and Atmospheric Research Utrecht Department of Physics and AstronomyUtrecht University3584 CC Utrechtthe Netherlands

A reduced-gravity barotropic shallow-water model was used to simulate the Kuroshio path variations. The results show that the model was able to capture the essential features of these path variations. We used one simulation of the model as the reference state and investigated the effects of errors in model parameters on the prediction of the transition to the Kuroshio large meander （KLM） state using the conditional nonlinear optimal parameter perturbation （CNOP-P） method. Because of their relatively large uncertainties, three model parameters were considered： the interracial friction coefficient, the wind-stress amplitude, and the lateral friction coefficient. We determined the CNOP-Ps optimized for each of these three parameters independently, and we optimized all three parameters simultaneously using the Spectral Projected Gradient 2 （SPG2） algorithm. Similarly, the impacts caused by errors in initial conditions were examined using the conditional nonlinear optimal initial perturbation （CNOP-I） method. Both the CNOP-I and CNOP-Ps can result in significant prediction errors of the KLM over a lead time of 240 days. But the prediction error caused by CNOP-I is greater than that caused by CNOP-P. The results of this study indicate not only that initial condition errors have greater effects on the prediction of the KLM than errors in model parameters but also that the latter cannot be ignored. Hence, to enhance the forecast skill of the KLM in this model, the initial conditions should first be improved, the model parameters should use the best possible estimates.

关键词： conditional nonlinear optimal perturbation Kuroshio large meander predictability model parameters

Impact of post-ruminally infused macronutrients on bovine mammary gland expression of genes involved in fatty acid synthesis, energy metabolism, and protein synthesis measured in RNA isolated from milk fat

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Journal of Animal Science and Biotechnology 2020年第4期11卷 1220-1231页

作者： Kelly Nichols AndréBannink Jurgen van Baal Jan dijkstra Animal Nutrition Group Wageningen University and ResearchPO Box 3386700AHWageningenthe Netherlands Wageningen Livestock Research Wageningen University and ResearchPO Box 3386700AHWageningenthe Netherlands

Background: Characterising the regulation of milk component synthesis in response to macronutrient supply is critical for understanding the implications of nutritional interventions on milk production. Gene expression in mammary gland secretory cells was measured using RNA isolated from milk fat globules from 6 Holstein-Friesian cows receiving 5-d abomasal infusions of saline, essential amino acids(AA), or glucose(GG) or palm olein(LG)without(LAA) or with(HAA) essential AA, according to a 6 × 6 Latin square design. RNA was isolated from milk fat samples collected on d 5 of infusion and subjected to real-time quantitative PCR. We hypothesised that m RNA expression of genes involved in de novo milk fatty acid(FA) synthesis would be differently affected by GG and LG,and that expression of genes regulating transfer of tricarboxylic acid cycle intermediates would increase at the HAA level. We also hypothesised that the HAA level would affect genes regulating endoplasmic reticulum(ER)homeostasis but would not affect genes related to the mechanistic target of rapamycin complex 1(m TORC1) or the integrated stress response(ISR) ***: Infusion of GG did not affect de novo milk FA yield but decreased expression of FA synthase(FASN).Infusion of LG decreased de novo FA yield and tended to decrease expression of acetyl-Co A carboxylase 1(ACC1).The HAA level increased both de novo FA yield and expression of ACC1, and tended to decrease expression of mitochondrial phosphoenolpyruvate carboxykinase(PCK2). m RNA expression of m TORC1 signaling participants was not affected by GG, LG, or AA level. Expression of the ε subunit of the ISR constituent eukaryotic translation initiation factor 2 B(EIF2 B5) tended to increase at the HAA level, but only in the presence of LG. X-box binding protein 1(XBP1) m RNA was activated in response to LG and the HAA ***: Results show that expression of genes involved in de novo FA synthesis responded to glucogenic,lipogenic, and

关键词： Cytoplasmic crescent Endoplasmic reticulum biogenesis Mammary cell Milk fat globule Milk synthesis Tricarboxylic acid cycle

How does male-male competition generate negative frequency-dependent selection and disruptive selection during speciation？

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Current Zoology 2018年第1期64卷 89-99页

作者： Peter D. dijkstra Shana E. BORDER Department of Biology Central Michigan University Mount Pleasant MI 48859 USA

Natural selection has been shown to drive population differentiation and speciation. The role of sexual selection in this process is controversial; however, most of the work has centered on mate choice while the role of male-male competition in speciation is relatively understudied. Here, we outline how male-male competition can be a source of diversifying selection on male competitive phenotypes, and how this can contribute to the evolution of reproductive isolation. We highlight how negative frequency-dependent selection （advantage of rare phenotype arising from stronger male-male competition between similar male phenotypes compared with dissimilar male pheno- types） and disruptive selection （advantage of extreme phenotypes） drives the evolution of diversity in competitive traits such as weapon size, nuptial coloration, or aggressiveness. We underscore that male-male competition interacts with other life-history functions and that variable male com- petitive phenotypes may represent alternative adaptive options. In addition to competition for mates, aggressive interference competition for ecological resources can exert selection on compet- itor signals. We call for a better integration of male-male competition with ecological interference competition since both can influence the process of speciation via comparable but distinct mecha- nisms. Altogether, we present a more comprehensive framework for studying the role of male-male competition in speciation, and emphasize the need for better integration of insights gained from other fields studying the evolutionary, behavioral, and physiological consequences of agonistic interactions.

关键词： disruptive selection life-history trade-offs male-male competition negative frequency-dependent selection speciation

Three-Dimensional Structure of Optimal Nonlinear Excitation for Decadal Variability of the Thermohaline Circulation

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Atmospheric and Oceanic Science Letters 2013年第6期6卷 410-416页

作者： ZU Zi-Qing MU Mu Henk A.dijkstra State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Ocean Circulation and Wave Institute of Oceanology Chinese Academy of Sciences Institute for Marine and Atmospheric Research Utrecht Department of Physics and Astronomy Utrecht University

The decadal variability of the North Atlantic thermohaline circulation(THC) is investigated within a three-dimensional ocean circulation model using the conditional nonlinear optimal perturbation method. The results show that the optimal initial perturbations of temperature and salinity exciting the strongest decadal THC variations have similar structures: the perturbations are mainly in the northwestern basin at a depth ranging from 1500 to 3000 m. These temperature and salinity perturbations act as the optimal precursors for future modifications of the THC, highlighting the importance of observations in the northwestern basin to monitor the variations of temperature and salinity at depth. The decadal THC variation in the nonlinear model initialized by the optimal salinity perturbations is much stronger than that caused by the optimal temperature perturbations, indicating that salinity variations might play a relatively important role in exciting the decadal THC variability. Moreover, the decadal THC variations in the tangent linear and nonlinear models show remarkably different characteristics, suggesting the importance of nonlinear processes in the decadal variability of the THC.

关键词： thermohaline circulation decadal variability conditional nonlinear optimal perturbation optimal precursor nonlinear processes

Resolution of phylogenetic relationships of the major subfamilies of the Delphacidae （Homoptera： Fulgoroidea） using the mitochondrial ribosomal DNA

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Insect Science 2006年第3期13卷 167-177页

作者： EDDY dijkstra MICHEL A. SLOTMAN RORY J. POST Biosystematics Group Wageningen University the Netherlands The Natural History Museum London UK

Delphacid relationships from the genus level to the subfamily have been completely resolved （among those taxa examined） using sequence data from the 3＇ end of the 12S gene. Monophyly of the non-asiracine subfamilies was strongly supported and the asiracine Ugyops was placed in the most basal position of the tree. Support levels for monophyly of the Delphacini increased after weighting transversions more heavily than transitions and after removing the cixiid outgroup from the dataset. Among the Delphacini, Conomelus and Megamelus were more closely related to each other than either was to Chloriona. These results are in agreement with the tree based on morphological characters. However, in contrast to morphological data our results strongly supported a sister group relationship between the Stenocraninae and the Kelisiinae. Although the 12S gene fragment gave some information about the species relationships within Chloriona, neither this fragment nor the 5＇ end of the 16S gene appear to be very useful for this level. Molecular evolutionary patterns provided evidence that there has been a shift in base composition from T to A during the early evolution of the non-Asiracinae. The non-Asiracinae also had comparatively fast substitution rates and these two observations are possibly correlated. In the ‘ modem＇ delphacid Chloriona, the AT content was comparatively low in regions free of constraints but this was not the case for ‘ non-modem＇ delphacids. The tRNA for valine has been translocated elsewhere, probably before the Delphacidae and Cixiidae diverged from each other.

关键词： classification Delphacidae evolution Fulgoroidea Homoptera rnitochondrial DNA phylogeny ribosomal DNA

MRCKα is a novel regulator of prolactin-induced lactogenesis in bovine mammary epithelial cells

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Animal Nutrition 2022年第3期10卷 319-328页

作者： Fang Wang Jürgen van Baal Lu Ma Xuejun Gao Jan dijkstra Dengpan Bu State Key Laboratory of Animal Nutrition Institute of Animal ScienceChinese Academy of Agricultural SciencesBeijing100193China Animal Nutrition Group Wageningen University and ResearchWageningen6708WDthe Netherlands College of Animal Science Yangtze UniversityJingzhou434020China Joint Laboratory on Integrated Crop-Tree-Livestock Systems of the Chinese Academy of Agricultural Sciences(CAAS) Ethiopian Institute of Agricultural Research(EIAR)and World Agroforestry Center(ICRAF)Beijing100193China

Myotonic dystrophy-related Cdc42-binding kinase alpha(MRCKα)is an integral component of signaling pathways controlling vital cellular processes,including cytoskeletal reorganization,cell proliferation and cell *** this study,we investigated the physiological role of MRCKα in milk protein and fat production in dairy cows,which requires a dynamic and strict organization of the cytoskeletal network in bovine mammary epithelial cells(BMEC).Within a selection of 9 Holstein cows,we found that both mRNA and protein expression of MRCKα in the mammary gland were upregulated during lactation and correlated positively(r>0.89)with the mRNA and protein levels of *** positive correlations(r>0.79)were found in a primary culture of BMEC stimulated with prolactin for 24 *** these cells,silencing of MRCKα decreased basal b-casein,sterol-regulatory element binding protein(SREBP)-1 and cyclin D1 protein level,phosphorylation of mTOR,triglyceride secretion,cell number and viabilitydwhile overexpression of MRCKα displayed the reversed ***,silencing of MRCKα completely prevented the stimulatory action of prolactin on the same *** data demonstrate that MRCKα is a critical mediator of prolactin-induced lactogenesis via stimulation of the mTOR/SREBP1/cyclin D1 signaling pathway.

关键词： Myotonic dystrophy-related Cdc42-binding kinase alpha Bovine mammary gland Prolactin Mechanistic target of rapamycin Sterol regulatory element-binding protein-1 Cyclin D1

Synergistic Effects of Biochar and NPK Fertilizer on Soybean Yield in an Alkaline Soil

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Pedosphere 2015年第5期25卷 713-719页

作者： Fatima Z.METE Shamim MIA Feike A.dijkstra Md.ABUYUSUF A.S.M.Iqbal HOSSAIN Department of Agronomy Patuakhali Science and Technology University Department of Environmental Science The University of Sydney

Biochar effects on legume growth and biological nitrogen fixation have been studied extensively, mostly in acidic soils with laboratory produced biochar. In the present study, a pot experiment in a full factorial experimental design was performed to examine soybean yield and nodulation of three genotypes grown with or without biochar and NPK fertilizers in an alkaline soil. We observed synergistic effects of biochar and NPK fertilizer applications on biomass and seed yields for all three soybean genotypes. Total biomass production and seed yield increased on average by 67% and 54%, respectively, with biochar and by 201% and 182% with NPK fertilizer application compared to the control. When applications of biochar and NPK fertilizer were combined, the increases were 391% and367%, respectively. However, the biomass production in the control was very low(692 kg ha-1) due to a high soil p H(8.80). The nodulation increased with biochar and NPK fertilizer applications, and was largest with the combined application. A correlation was found between leaf chlorophyll content(single photon avalanche diode value) and nodule number. We suggested that the synergistic increase in yield was due to a decrease in soil p H caused by biochar and NPK fertilizer applications thereby increasing P availability in this alkaline soil.

关键词： biological nitrogen fixation biomass production P availability seed yield soil pH