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Li L (2023) Untangling microbial community assembly in rainforest and grassland soils under increasing precipitation persistence. 179 p
Abstract: Climate change is causing alterations in precipitation patterns, leading to adverse ecological consequences in many ecosystems. Recently, an increasingly persistent weather pattern has emerged, characterized by lengthening the duration of alternating dry and wet periods, which is more complex than exclusively drought or increasing precipitation. It is currently unclear how soil microbial communities respond to these new regimes in relation to their interactions with plants, especially in precipitation-sensitive ecosystems, such as tropical rainforests and grasslands. In this thesis, we explored responses of soil bacterial and fungal communities to increasing weather persistence in rainforests and grasslands, using high throughput sequencing technology. We firstly investigated the resistance and resilience of microbial communities to prolonged drought in a mature seasonal tropical rainforest which experiences unusually intensive dry seasons in the current century. Through excluding rainfall during and after the dry season, a simulated prolongation of the dry season by five months was compared to the control. Our results indicate that as rain exclusion progressed, the microbial communities increasingly diverged from the control, indicating a moderate resistance to prolonged drought. However, when the drought ceased, the composition and co-occurrence patterns of soil microbial communities immediately recovered to that in the control, implying a high resilience. To further investigate the ecological roles of soil microbial communities in response to increasing weather persistence, we set up grassland mesocosm experiments. In these experiments, precipitation frequency was adjusted along a series, ranging from 1 to 60 consecutive days alternating of dry and wet periods, while keeping the total precipitation constant. Our results show that microbial community assembly tended to be more stochastic processes at intermediate persistence of dry and wet alternations while more deterministic processes dominated at low and high persistence within 120 days regime exposure. Moreover, more persistent precipitation reduced the fungal diversity and network connectivity but barely impacted that of bacterial communities. The prior experiences of persistent weather events for one year caused legacy effects. The soil microbial legacy induced by soil microbial communities subjected to prior persistent weather events was more enduring in subsequent fungal communities than bacterial communities, likely due to slower growth of fungi compared to bacteria. However, a minor effect of soil microbial legacy was observed on plant performance. In addition, we kept the grassland mesocosm experiment for two growing seasons. The effects of precipitation persistence on soil microbial communities increased in the second year. The dissimilarities of microbial communities between the first and second year were less with more persistent precipitation, potentially resulting in more vulnerable microbial communities, due to some taxa disappearing and a reduction in functional redundancy under more persistent weather. To conclude, our findings provide a comprehensive theoretical understanding of soil microbial communities in response to the current and future climate change, drawing from both natural and experimental systems. It helps in predicting and managing the impacts of future climate change on ecosystems mediated by microbial communities. Additionally, the findings of microbe-mediated legacy effects on grassland ecosystems can provide practical guidance for their application in agriculture, specifically for using an inoculum to mitigate the impacts of climate change.
Keywords: Doctoral thesis; Integrated Molecular Plant Physiology Research (IMPRES); Plant and Ecosystems (PLECO) – Ecology in a time of change
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Montiel FN (2024) Voltage against illicit drug trafficking : capabilities of electrochemical fingerprinting to detect illicit drugs. 256 p
Keywords: Doctoral thesis; Pharmacology. Therapy; Engineering sciences. Technology; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
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“Classical atomic bilayers”. Peeters FM, Partoens B, Schweigert VA, Schweigert IV Plenum Press, New York, page 523 (1998).
Keywords: H1 Book chapter; Condensed Matter Theory (CMT)
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Blumenau AT, Frauenheim T, Ö,berg S, Willems B, Van Tendeloo G (2004) Dislocation structures in diamond: density-functional based modelling and high resolution electron microscopy. Trans Tech Publications, s.l
Keywords: MA1 Book as author; Electron microscopy for materials research (EMAT)
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“Investigation of Ag, Ag2S and Ag(Br,I) small particles by HREM and AEM”. Oleshko V, Schryvers D, Gijbels R, Jacob W s.l., page 293 (1998).
Keywords: H3 Book chapter; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Large bipolarons and high-Tc materials”. Devreese JT, Verbist G, Peeters FM Cambridge University Press, Cambridge, page 385 (1995).
Keywords: H3 Book chapter; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems
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“MgB2 : superconductivity and pressure effects”. Ivanov VA, Betouras JJ, Peeters FM, , 35 (2003)
Abstract: We present a Ginzburg-Landau theory for a two-band superconductor with emphasis on MgB2. We propose experiments which lead to identification of the possible scenarios: whether both sigma- and pi-bands superconduct or sigma-alone. According to the second scenario a microscopic theory of superconducting MgB2 is proposed based on the strongly interacting or-electrons and non-correlated pi-electrons of boron ions. The kinematic and Coulomb interactions of sigma-electrons provide the superconducting state with an anisotropic gap of s(*)-wave symmetry. The critical temperature T-c has a non-monotonic dependence on the distance r between the centers of gravity of sigma- and pi-bands. The position of MgB2 on a bell-shaped curve T-c (r) is identified in the overdoped region. The derived superconducting density of electronic states is in agreement with available experimental and theoretical data. It is argued that the effects of pressure are crucial to identify the microscopic origin of superconductivity in MgB2. Possibilities for increase of T, are discussed.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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Goorden L, Van Tendeloo G, Lenaerts S, Deblonde M, et al. (2009) Nanotechnologie: gewikt en gewogen. NanoSoc
Keywords: Minutes and reports; Engineering sciences. Technology; Engineering Management (ENM); Sustainable Energy, Air and Water Technology (DuEL); Electron microscopy for materials research (EMAT)
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Goorden L, Van Tendeloo G, Lenaerts S, Deblonde M, van Oudheusden M, et al. (2009) Nanotechnologie op de agenda. NanoSoc
Keywords: Minutes and reports; Engineering sciences. Technology; Engineering Management (ENM); Society and Environment; Sustainable Energy, Air and Water Technology (DuEL); Electron microscopy for materials research (EMAT)
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“Semiconductor”. Peeters FM McGraw-Hill, New York, page 350 (1997).
Keywords: H3 Book chapter; Condensed Matter Theory (CMT)
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“Superconducting nanowires: quantum-confinement effect on the critical magnetic field and supercurrent”. Croitoru MD, Shanenko AA, Peeters FM, , 327 (2010). http://doi.org/10.1142/9789814289153_0025
Abstract: We study the effect, of electron confinement on the superconducting-to-normal phase transition driven by a magnetic field and/or on the current-carrying state of the superconducting condensate in nanowires. Our investigation is based on a self-consistent. numerical solution of the Bogoliubov-de Gennes equations. We show that, in a parallel magnetic field and/or in the presence of supercurrent the transition from superconducting to normal phase occurs as a cascade of discontinuous jumps in the superconducting order parameter for diameters D < 10 divided by 15 nm at T = 0. The critical magnetic held exhibits quantum-size oscillations with pronounced resonant enhancements.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
DOI: 10.1142/9789814289153_0025
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“Terahertz absorption window in bilayer graphene”. Dong HM, Qin H, Zhang J, Peeters FM, Xu W Ieee, New York, N.Y., page 247 (2009).
Abstract: We present a detailed theoretical study of terahertz (THz) optical absorption in bilayer graphene. Considering an air/graphene/dielectric-wafer system, we find that there is an absorption window in the range 3 similar to 30 THz. Such an absorption window is induced by different transition energies required for inter- and intra-band optical absorption in the presence of the Pauli blockade effect. As a result, the position and width of this THz absorption window depend sensitively on temperature and carrier density of the system. These results are pertinent to the applications of recently developed graphene systems as novel optoelectronic devices such as THz photo-detectors.
Keywords: H1 Book chapter; Condensed Matter Theory (CMT)
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“Tuning the superconducting properties of nanomaterials”. Croitoru MD, Shanenko AA, Peeters FM Springer, Dordrecht, page 1 (2009).
Abstract: Electron continement and its effect on the superconducting-to-normal phase transition driven by a magentic field and/or a current is studied in nanowires. Our investigation is based on a self-consistent numerical solution of the Bogoliubov-de Gennes equations. We find that in a parallel magneitc field and/or in the presence of a supercurrent the transition from the superconducting to the normal phase occurs as a cascade of discontinuous jumps in the superconducting order parameter for diameters D < 10 divided by 15 nm at T = 0. The critical magentic field exhibits quantum-size oscillations with pronounced resonant enhancements as a function of the wire radius.
Keywords: H1 Book chapter; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
DOI: 10.1007/978-90-481-3120-4_1
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“Glow discharge optical spectroscopy and mass spectrometry”. Bogaerts A John Wiley & Sons, Chichester, page 1 (2016).
Abstract: Atomic Spectroscopy Optical (atomic absorption spectroscopy, AAS; atomic emission spectroscopy, AES; atomic fluorescence spectroscopy, AFS; and optogalvanic spectroscopy) and mass spectrometric (magnetic sector, quadrupole mass analyzer, QMA; quadrupole ion trap, QIT; Fourier transform ion cyclotron resonance, FTICR; and time-of-flight, TOF) instrumentation are well suited for coupling to the glow discharge (GD). The GD is a relatively simple device. A potential gradient (500–1500 V) is applied between an anode and a cathode. In most cases, the sample is also the cathode. A noble gas (mostly Ar) is introduced into the discharge region before power initiation. When a potential is applied, electrons are accelerated toward the anode. As these electrons accelerate, they collide with gas atoms. A fraction of these collisions are of sufficient energy to remove an electron from a support gas atom, forming an ion. These ions are, in turn, accelerated toward the cathode. These ions impinge on the surface of the cathode, sputtering sample atoms from the surface. Sputtered atoms that do not redeposit on the surface diffuse into the excitation/ionization regions of the plasma where they can undergo excitation and/or ionization via a number of collisional processes, and the photons or ions created in this way can be detected with optical emission spectroscopy or mass spectrometry. GD sources offer a number of distinct advantages that make them well suited for specific types of analyses. These sources afford direct analysis of solid samples, thus minimizing the sample preparation required for analysis. The nature of the plasma also provides mutually exclusive atomization and excitation processes that help to minimize the matrix effects that plague so many other elemental techniques. In recent years, there is also increasing interest for using GD sources for liquid and gas analyses. In this article, first, the principles of operation of the GD plasma are reviewed, with an emphasis on how those principles relate to optical spectroscopy and mass spectrometry. Basic applications of the GD techniques are considered next. These include bulk analysis, surface analysis, and the analysis of solution and gaseous samples. The requirements necessary to obtain optical information are addressed following the analytical applications. This article focuses on the instrumentation needed to make optical measurements using the GD as an atomization/excitation source. Finally, mass spectrometric instrumentation and interfaces are addressed as they pertain to the use of a GD plasma as an ion source. GD sources provide analytically useful gas-phase species from solid samples. These sources can be interfaced with a variety of spectroscopic and spectrometric instruments for both quantitative and qualitative analyses.
Keywords: H1 Book chapter; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Berry phase engineering at oxide interfaces”. Groenendijk DJ, Autieri C, van Thiel TC, Brzezicki W, Hortensius JR, Afanasiev D, Gauquelin N, Barone P, van den Bos KHW, van Aert S, Verbeeck J, Filippetti A, Picozzi S, Cuoco M, Caviglia AD, 2, 023404 (2020). http://doi.org/10.1103/PhysRevResearch.2.023404
Abstract: Three-dimensional strontium ruthenate (SrRuO3) is an itinerant ferromagnet that features Weyl points acting as sources of emergent magnetic fields, anomalous Hall conductivity, and unconventional spin dynamics. Integrating SrRuO3 in oxide heterostructures is potentially a novel route to engineer emergent electrodynamics, but its electronic band topology in the two-dimensional limit remains unknown. Here we show that ultrathin SrRuO3 exhibits spin-polarized topologically nontrivial bands at the Fermi energy. Their band anticrossings show an enhanced Berry curvature and act as competing sources of emergent magnetic fields. We control their balance by designing heterostructures with symmetric (SrTiO3/SrRuO3/SrTiO3 and SrIrO3/SrRuO3/SrIrO3) and asymmetric interfaces (SrTiO3/SrRuO3/SrIrO3). Symmetric structures exhibit an interface-tunable single-channel anomalous Hall effect, while ultrathin SrRuO3 embedded in asymmetric structures shows humplike features consistent with multiple Hall contributions. The band topology of two-dimensional SrRuO3 proposed here naturally accounts for these observations and harmonizes a large body of experimental results.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 58
DOI: 10.1103/PhysRevResearch.2.023404
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“A temperature study of mixed AgBr-AgBrI tabular crystals”. Goessens C, Schryvers D, van Landuyt J, Geuens I, Gijbels R, Jacob W, de Keyzer R Hawaii, page 70 (1995).
Keywords: H1 Book chapter; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Times cited: 3
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“The influence of the secondary electron emission coefficient and effect of the gas heating on the calculated electrical characteristics of a grimm type glow discharge cell”. Derzsi A, Donko Z, Bogaerts A, Hoffmann V, , 285 (2008)
Abstract: Electron emission properties of cathode surfaces affect considerably the electrical characteristics of glow discharges. Using a heavy-particle hybrid model ill 2 dimensions, we investigate the influence of the secondary electron emission coefficient gamma oil the calculated discharge characteristics for both 'clean' and 'dirty' cathode surface conditions, and assuming a constant gamma parameter as well. The effect of the gas heating and the role of the heavy particles reflected from the cathode on this process is also studied.
Keywords: P1 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Modeling of a dielectric barrier discharge used as a flowing chemical reactor”. Petrovic D, Martens T, van Dijk J, Brok WJM, Bogaerts A, , 262 (2008)
Keywords: P1 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Sputtering of Si(001) and SiC(001) by grazing ion bombardment”. Elmonov AA, Yusupov MS, Dzhurakhalov AA, Bogaerts A, , 209 (2008)
Abstract: The peculiarities of sputtering processes at 0.5-5 keV Ne grazing ion bombardment of Si(001) and SiC(001) surfaces and their possible application for the surface modification have been studied by computer simulation. Sputtering yields in the primary knock-on recoil atoms regime versus the initial energy of incident ions (E(0) = 0.5-5 keV) and angle of incidence (psi = 0-30 degrees) counted from a target surface have been calculated. Comparative studies of layer-by-layer sputtering for Si(001) and SiC(001) surfaces versus the initial energy of incident ions as well as an effective sputtering and sputtering threshold are discussed.
Keywords: P1 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“On the phase-like nature of the 7m structure in ni-al”. Schryvers D, Tanner LE, , 849 (1994)
Keywords: P1 Proceeding; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Times cited: 1
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