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Harvesting of forest products and implications for Afrotemperate bird communities in a montane forest of the Eastern cape, South Africa

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Forest Ecosystems 2019年第4期6卷 352-366页

作者： Jessica Leaver johann c.carstens Michael I.cherry Department of Botany and Zoology Stellenbosch University

Background: Harvesting of forest products is a widespread driver of disturbance in developing nations, where policies are increasingly aimed at managing natural forests for sustainable use. There is thus need for research aimed at understanding the impact of resource use on forest habitats and concomitant effects on *** forests in the Eastern cape, South Africa are harvested informally for poles and medicinal bark and occur along elevational gradients of 800–1600 m above sea level. Patterns of spatial diversity and human disturbance are expected to be affected by elevation. Furthermore, species’ responses to disturbance are expected to vary depending on their level of habitat specialisation. Understanding harvest impacts on forest biodiversity thus requires disentangling the separate effects of elevation and disturbance, and considering forest-specialist and forest-generalist species separately. This study comprises two components. First, harvest activities, resultant harvestmediated habitat heterogeneity, and avifaunal species richness, composition and beta-diversity were compared across two elevational zones in a harvested forest. Second, the role of harvest-mediated habitat heterogeneity in driving patterns of avifaunal diversity were assessed, while controlling for elevation, and considering forest-specialist and forest-generalist species ***: Harvest rates were higher, and activities more varied in the lower elevation zone, with significant impacts of harvesting on habitat features resulting in higher harvest-mediated habitat heterogeneity at lower ***-mediated increases in habitat heterogeneity positively affected forest-generalist species richness, while forest-specialist richness was negatively affected. While species composition of both groups differed across elevational zones, variation in harvest-mediated habitat heterogeneity did not fully account for this, suggesting that factors other than disturbance

关键词： Human disturbance Habitat heterogeneity Habitat modification Beta-diversity Elevation Generalist species Forest-specialist species

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On the structure in the ΛN cross section at the ∑N threshold

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chinese Physics c 2021年第9期45卷 157-166页

作者： johann Haidenbauer Uf-G.MeiBner Institute for Advanced Simulation Institut fur Kemphysik and Julich Center for Hadron PhysicsForschungszentrum JulichD-52425 JulichGermany Helmholtz-Institut fiir Strahlen-und Kemphysik and Bethe center for Theoretical Physics Universitat Bonn53115 BonnGermany Tbilisi State University 0186 TbilisiGeorgia

The complexity of threshold phenomena is exemplified on a prominent and long-known case-the structure in theΛp cross section(invariant mass spectrum)at the opening of the∑N *** mass splitting between the∑baryons together with the angular momentum coupling in the^(3)S_(1)-^(3)D_(1)partial wave imply that,in principle,up to six channels are *** hyperon-nucleon potentials that provide an excellent description of the available low-energy Λp and∑N scattering data,the shape of the resulting Λp cross section is discussed and the poles near the ∑N threshold are *** for a strangeness S=-1 dibaryon is provided,in the form of a(unstable)∑N bound state in the vicinity of the ∑N *** for level shifts and widths of ∑^(-)p atomic states are given.

关键词： hyperon-nucleon interaction dibaryon threshold effects

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Neutron-antineutron oscillations in the deuteron studied with NN and ■N interactions based on chiral effective field theory

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chinese Physics c 2020年第3期44卷 28-32页

作者： johann Haidenbauer Ulf-G.Meiβner Institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron PhysicsForschungszentrum JülichD-52425 JülichGermany Helmholtz-Institut für Strahlen-und Kernphysik and Bethe center for Theoretical Physics Universität Bonn53115 BonnGermany Tbilisi State University 0186 TbilisiGeorgia

Neutron-antineutron(n−n)oscillations in the deuteron are ***,the deuteron lifetime is calculated in terms of the free-space n−n oscillation time τn−n based on NN and NN interactions derived within chiral effective field theory(EFT).This results in(2.6±0.1)×10^22τ2^n−n s,which is close to the value obtained by Dover and collaborators more than three decades ago,but disagrees with recent EFT calculations that were performed within the perturbative scheme proposed by Kaplan,Savage,and *** reasons for the difference are discussed.

关键词： neutron-antineutron oscillations chiral effective field theory NN interaction antinucleon-nucleon interaction

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Simulated MRI Artifacts:Testing Machine Learning Failure Modes

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Biomedical Engineering Frontiers 2022年第1期3卷 437-452页

作者： Nicholas c.Wang Douglas c.Noll Ashok Srinivasan johann Gagnon-Bartsch Michelle M.Kim Arvind Rao Department of computational Medicine and Bioinformatics University of MichiganUSA Department of Biomedical Engineering University of MichiganUSA Department of Radiology University of MichiganUSA Department of Radiology Division of NeuroradiologyUniversity of MichiganUSA Rogel cancer center University of MichiganUSA Frankel cardiovascular center University of MichiganUSA Department of Statistics University of MichiganUSA Department of Radiation Oncology University of MichiganUSA

*** types of MRI artifacts,including acquisition and preprocessing errors,were simulated to test a machine learning brain tumor segmentation model for potential failure ***-world medical deployments of machine learning algorithms are less common than the number of medical research papers using machine *** of the gap between the performance of models in research and deployment comes from a lack of hard test cases in the data used to train a *** failure modes were simulated for a pretrained brain tumor segmentation model that utilizes standard MRI and used to evaluate the performance of the model under *** simulated MRI artifacts consisted of motion,susceptibility induced signal loss,aliasing,field inhomogeneity,sequence mislabeling,sequence misalignment,and skull stripping *** artifact with the largest effect was the simplest,sequence mislabeling,though motion,field inhomogeneity,and sequence misalignment also caused significant performance *** model was most susceptible to artifacts affecting the FLAIR(fluid attenuation inversion recovery)***,these simulated artifacts could be used to test other brain MRI models,but this approach could be used across medical imaging applications.

关键词： utilize stripping susceptibility

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Single photon emission and recombination dynamics in self-assembled GaN/AlN quantum dots

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Light(Science & Applications) 2022年第5期11卷 751-765页

作者： johann Stachurski Sebastian Tamariz Gordon callsen Raphaël Butté Nicolas Grandjean Institute of Physics École Polytechnique Fédérale de LausanneEPFLCH-1015 LausanneSwitzerland Present address:Universitécôte d’Azur CNRSCRHEAF-06560 ValbonneFrance Present address:Institut für Festkörperphysik Universität Bremen28359 BremenGermany

Ⅲ-nitride quantum dots(QDs)are a promising system actively studied for their ability to maintain single photon emission up to room ***,we report on the evolution of the emission properties of self-assembled GaN/AlN QDs for temperatures ranging from 5 to 300 *** carefully track the photoluminescence of a single QD and measure an optimum single photon purity of g^((2))(0)=0.05±0.02 at 5 K and 0.17±0.08 at 300 *** complement this study with temperature dependent time-resolved photoluminescence measurements(TRPL)performed on a QD ensemble to further investigate the exciton recombination dynamics of such polar zero-dimensional *** comparing our results to past reports,we emphasize the complexity of recombination processes in this *** of the more conventional mono-exponential decay typical of exciton recombination,TRPL transients display a bi-exponential feature with short-and long-lived components that persist in the low excitation *** the temperature insensitivity of the long-lived excitonic component,we first discard the interplay of dark-to-bright state refilling in the exciton recombination ***,this temperature-invariance also highlights the absence of nonradiative exciton recombinations,a likely direct consequence of the strong carrier confinement observed in GaN/AlN QDs up to 300 ***,our results support the viability of these dots as a potential single-photon source for quantum applications at room temperature.

关键词： temperature. process. quantum

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The phylogeny of francolins(Francolinus, Dendroperdix, Peliperdix and Scleroptila) and spurfowls(Pternistis) based on chick plumage(Galliformes: Phasianidae)

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Avian Research 2018年第1期9卷 1-18页

作者： johann H.van Niekerk Tshifhiwa G.Mandiwana-Neudani Department of Environmental Sciences College of Agriculture and Environmental ScienceUniversity of South Africa Department of Biodiversity University of Limpopo

Background: This paper describes the chick plumage of spurfowl(Pternistis) and francolin(Francolinus, Dendroperdix Peliperdix and Scleroptila) chicks, tests its significance for phylogenetic relationships and also explores the patterns of character evolution in the francolin and spurfowl *** regarded as monophyletic, the two evolutionar?ily distant clades are now divided into five *** considered were whether chick plumage supports the dichotomy between spurfowls and francolins and what role habitat matching ***: The study was based mainly on photographs of chick skins from the American Museum of Natural History and the Natural History Museum at *** plumage characters were selected for comparative scoring, summa?rised in a *** characters were subsequently analysed phylogenetically and their evolution was traced on the existing molecular phylogeny using a parsimony ***: Based on chick plumage the phylogeny of species groups among francolins and spurfowls, was largely unresolved possibly ascribed to a high degree of symplesiomorphy inherent among the *** possibly could have resulted in a high degree of polytomy particularly among the spurfowls and ***, the ancestral state reconstructions revealed high prevalence of symplesiomorphic states and reversals which do not help in the classification of *** the differences are described that separate some African francolins from spurfowls, other francolins(in Asia and Africa) share remarkably similar characteristics with *** dark dorsal plumage is probably advantageous for avoiding detection by predators in forests, while facial stripes optimise the breaking of body shapes in dense grass cover(as in Scleroptila spp.) and semi?striped faces are advantageous for stationary camouflage under tree and bush cover(as in Pternistis spp.).conclusions: Although symplesiomorphy is a hereditary explanation for downy c

关键词： Spurfowl Francolin Phasianidae chick plumage Phylogeny Ancestral state reconstruction Habitat

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Tumor–stromal cross-talk modulating the therapeutic response in pancreatic cancer

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Hepatobiliary & Pancreatic Diseases International 2018年第5期17卷 461-472页

作者： christopher c.M.Neumann Ellen von Horschelmann Anja Reutzel-Selke Elisabeth Seidel Igor Maximilian Sauer johann Pratschke Marcus Bahra Rosa Bianca Schmuck Department of Surgery Campus Charité Mitte Campus Virchow-KlinikumExperimental SurgeryCharité-Universitatsmedizin BerlinBerlinGermany Berlin Institute of Health Department of SurgeryCampus CharitéMitte and Campus Virchow-KlinikumAugustenburger Platz 113353 BerlinGermany

Background: Pancreatic ductal adenocarcinoma(PDAc) is a highly malignant solid tumor with a dismal prognosis. The stroma component makes up to 90% of the tumor mass and is thought to be one of the main reasons for the tumor’s high chemoresistance. cancer associated fibroblasts(cAFs) have previously been identified to be the key stromal players. This is the first time we provide detailed in vitro experiments investigating tumor–stromal interactions when exposed to three well-known chemotherapeutic agents. Methods: Monocultures, indirect and direct co-cultures of two PDAc cell lines(AsPc and Panc-1) and six primary patients derived cAFs were treated with gemcitabine, nab-paclitaxel and the γ-secretaseinhibitor(GSI) DAPT. The cell viability of each component was measured with XTT. Finally, IL-6 concentrations of the supernatants were analyzed. Results: On the contrary to PDAc cell lines, cAF monocultures hardly responded to any treatment which suggested that stroma(cAFs) itself is more resistant to standard chemo-treatments than the epithelial cancer cells. Moreover, only a weak chemotherapeutic response was observed in direct co-cultures of cancer cells with cAFs. A change in the morphology of direct co-cultures was accompanied with the chemoresistance. cAFs were observed to build cage-like structures around agglomerates of tumor cells. High levels of IL-6 were also associated with a reduced response to therapy. Indirect co-cultures make the tumor–stromal interaction more complex. conclusions: cAFs are highly chemoresistant. Direct cell–cell contact and high levels of IL-6 correlate with a high chemoresistance.

关键词： Pancreatic cancer Tumor microenvironment cancer associated fibroblasts cancer–stroma co-culture Atroma targeted therapy

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“Autoinflammatory psoriasis”-genetics and biology of pustular psoriasis

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cellular & Molecular Immunology 2021年第2期18卷 307-317页

作者： Ranjitha Uppala Lam c.Tsoi Paul W.Harms Bo Wang Allison c.Billi Emanual Maverakis J.Michelle Kahlenberg Nicole L.Ward johann E.Gudjonsson Graduate Program in Immunology University of MichiganAnn ArborMIUSA Department of Dermatology University of MichiganAnn ArborMIUSA Department of Pathology University of MichiganAnn ArborMIUSA Department of Dermatology University of CaliforniaDavisSacramentoCAUSA Division of Rheumatology Department of Internal MedicineUniversity of MichiganAnn ArborMIUSA A.Alfred Taubman Medical Research Institute Ann ArborMIUSA Departments of Nutrition and Dermatology Case Western Reserve UniversityClevelandOHUSA

Psoriasis is a chronic inflammatory skin condition that has a fairly wide range of clinical *** psoriasis,which is the most common manifestation of psoriasis,is located on one end of the spectrum,dominated by adaptive immune responses,whereas the rarer pustular psoriasis lies on the opposite end,dominated by innate and autoinflammatory immune *** recent years,genetic studies have identified six genetic variants that predispose to pustular psoriasis,and these have highlighted the role of IL-36 cytokines as central to pustular psoriasis *** this review,we discuss the presentation and clinical subtypes of pustular psoriasis,contribution of genetic predisposing variants,critical role of the IL-36 family of cytokines in disease pathophysiology,and treatment perspectives for pustular *** further outline the application of appropriate mouse models for the study of pustular psoriasis and address the outstanding questions and issues related to our understanding of the mechanisms involved in pustular psoriasis.

关键词： Pustular psoriasis Genetics IL-36 Autoinflammation clinical features Histology

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Increased chemical reactivity of single-walled carbon nanotubes on oxide substrates： In situ imaging and effect of electron and laser irradiations

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Nano Research 2016年第2期9卷 517-529页

作者： Hasan-al Mehedi johann Ravaux Khadija Yazda Thierry Michel Said Tahir Michael Odorico Renaud Podor Vincent Jourdain Laboratoire charles coulomb (L2c) UMR 5221 CNRS-Universite de Montpellier 34095 Mon tpellier France Institut de chimie Separative de Marcoule UMR 5257 CEA-CNRS-UM2-ENSCM Site de Marcoule Bat 426 BP 17171 30207 Bagnols sur Ceze cedex France

We studied the oxygen etching of individual single-walled carbon nanotubes on silicon oxide substrates using atomic force microscopy and high-temperature environmental scanning electron microscopy. Our in situ observations show that carbon nanotubes are not progressively etched from their ends, as frequently assumed, but disappear segment by segment. Atomic force microscopy, before and after oxidation, reveals that the oxidation of carbon nanotubes on substrates proceeds through a local cutting that is followed by a rapid etching of the disconnected nanotube segment. Unexpectedly, semiconducting nanotubes appear more reactive under these conditions than metallic ones. We also show that exposure to electron and laser beams locally increases the chemical reactivity of carbon nanotubes on such substrates. These results are rationalized by considering the effect of substrate-trapped charges on the nanotube density of states close to the Fermi level, which is impacted by the substrate type and the exposure to electron and laser beams.

关键词： single-walled carbon nanotubes environmental scanning electron microscopy oxidative etching substrate-trapped charges electron and laser irradiations

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Metamorphic stages in mountain belts during a Wilson cycle:A case study in the central Sanandaj-Sirjan zone(Zagros Mountains,Iran)

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Geoscience Frontiers 2022年第2期13卷 430-459页

作者： Farzaneh Shakerardakani Franz Neubauer Manfred Bernroider Fritz Finger christoph Hauzenberger johann Genser Michael Waitzinger Behzad Monfaredi Department of Geography and Geology Paris-Lodron University of SalzburgHellbrunner Str.34A-5020 SalzburgAustria State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China Department of chemistry and Physics of Materials Paris-Lodron University of SalzburgAustria Institute of Earth Sciences-NAWI Graz Geocenter University of GrazUniversitatsplatz 2Graz 8010Austria

Polymetamorphic units are important constituents of continent-continent collisional orogens,and rift metamorphic assemblages are often overprinted by subsequent metamorphism during subduction and *** study reports the metamorphic conditions and evolution of the Dorud-Azna metamorphic units in the central part of the Sanandaj-Sirjan zone(SSZ),***,new geothermobarometry results are integrated with ^(40)Ar/^(39)Ar mineral and Th-U-Pb monazite and thorite ages to provide new insight of polyphase metamorphism in the two different basement units of the SSZ,the lower Galeh-Doz orthogneiss and higher Amphibolite-Metagabbro *** the Amphibolite-Metagabbro unit,staurolite micaschist underwent a prograde P-T evolution from 640±20℃/6.2±0.8 kbar in garnet cores(M1)to 680±20℃/7.2±1.0 kbar in garnet rims(M2).Three Th-U-Pb monazite ages of 306±5 Ma,322±28 Ma and 336±39 Ma from the garnet-micaschists testify the carboniferous age of M1 *** the same unit,the metagabbro records P-T conditions of 4.0±0.8 kbar and 580±50℃ in the(magmatic)amphibole core(Late carboniferous intrusion)to 7.5±0.7 kbar and 700±20℃ in the amphibole rim indicating a prograde P-T path during subsequent burial(M1).New ^(40)Ar/^(39)Ar dating of white mica from the staurolite micaschist yielded a staircase pattern ranging from 36±12 Ma to 170±2 *** implies polymetamorphism with a minimum Late Jurassic cooling age through the Ar retention temperature of ca.425±25℃ after M2 metamorphism and a Paleogene low-grade metamorphic overprint(M3),while ^(40)Ar/^(39)Ar white mica dating of garnet micaschist yielded a plateau age of 137.84±0.65 *** therefore interpret the amphibolite-grade metamorphism M2 to have predated 170 Ma and is likely between 180 and 200 ***,it is overprinted at about 36 Ma under retrogressive low-grade M3 metamorphism(at temperatures of~350-240℃)during final shortening and *** the underlying Galeh-Doz unit,the Panafrican granitic orthogneiss i

关键词： carboniferous Polyphase metamorphism Petrochronology chemical Th-U-Pb age dating ^(40)Ar/^(39)Ar dating collisional orogen

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