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Birds’Diversity in Kalfou Forest Reserve and Its Peripheral Zone, Far North, Cameroon

Open Journal of Animal Sciences 2024年第2期14卷 137-155页

作者： Ghislain Noé Kougoum Piebeng Simon A. Tamungang Daksala Wansang Jean Tonleu Laurentine Soufo Muhammad Bilal Awa II taku Alexis Teguia Department of Biological Sciences Faculty of Science University of Maroua Maroua Cameroon Department of Animal Biology Faculty of Science University of Dschang Dschang Cameroon Department of Forestry and Wildlife Technology College of Technology University of Bamenda Bamenda Cameroon Department of Environmental Sciences Higher Polytechnical Training School University of Maroua Maroua Cameroon Department of Biology Virtual University of Pakistan Rawalpindi Campus Punjab Pakistan Department of Animal Production Faculty of Agronomy and Agricultural Science University of Dschang Dschang Cameroon

The Far North Region of Cameroon is home to a great diversity of bird species, which unfortunately remains very little explored. This work was initiated to establish an inventory of birds and the factors affecting their diversity and distribution for sustainable management in the Kalfou Forest Reserve (KFR) and its periphery. Two methods were used for sampling, linear strip transects from which direct counts and indirect observations were made and the mist netting to complement the first. In total, 2525 birds were observed, including 149 species, belonging to 20 orders and 55 families. Accipitridae had the greatest number of species (11). The species richness was greater in the KFR (117 species) compared to the periphery (95 species). The specific richness was higher in wooded savannah compared to other habitats. Shannon index was significantly higher in the KFR (3.99) compared to that obtained in the periphery (3.80). The value of the Simpson index was higher on the outskirts of the KFR than on the periphery. The indices of species diversity were greater in the wooded savannah compared to other vegetation types. The seasons had no influence on bird diversity. Among the human activities encountered, the pressure indices were more important for grazing (7.3 contacts/km). Human activities have resulted in a significant decrease in specific richness. Six endangered species were encountered, four belonging to the Accipitridae family. The greater bird diversity in the reserve compared to the periphery shows that protected areas are a long-term solution for biodiversity conservation.

关键词： Bird Diversity Habitats Bird Species Human Activities Conservation Kalfou

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Heterogeneous tunable Ⅲ-Ⅴ-on-silicon-nitride mode-locked laser emitting wide optical spectra

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Photonics Research 2024年第3期12卷 I0021-I0027页

作者： MAXIMILIEN BILLET STIJN CUYVERS STIJN POELMAN ARTUR HERMANS SANDEEP SEEMA SASEENDRA TASUKU NAKAMURA SHINYA OKAMOTO YASUHISA INADA KAZUYA HISADA taku HIRASAWA JOAN RAMIREZ DELPHINE NÉEL NICOLAS VAISSIÈRE JEAN DECOBERT PHILIPPE SOUSSAN XAVIER ROTTENBERG GUNTHER ROELKENS JONØ.KJELLMAN BART KUYKEN Photonics Research Group Department of Information TechnologyGhent University-imec9052 GhentBelgium imec 3001 LeuvenBelgium Technology Division Panasonic Holdings CorporationMoriguchi-CityOsakaJapan Ⅲ-Ⅴ Lab F91767 PalaiseauFrance

We demonstrate a Ⅲ-Ⅴ-on-silicon-nitride mode-locked laser through the heterogeneous integration of a semiconductor optical amplifier on a passive silicon-nitride cavity using the technique of micro-transfer printing. In the initial phase of our study, we focus on optimizing the lasing wavelength to be centered at 1550 nm. This optimization is achieved by conducting experiments with 27 mode-locked lasers, each incorporating optical amplifiers featuring distinct multiple-quantum-well photoluminescence values. Subsequently we present a comprehensive study investigating the behavior of the mode-locking regime when the electrical driving parameters are varied. Specifically, we explore the impact of the gain voltage and saturable absorber current on the locking stability of a tunable mode-locked laser. By manipulating these parameters, we demonstrate the precise control of the optical spectrum across a wide range of wavelengths spanning from 1530 to 1580 nm. Furthermore, we implement an optimization approach based on a Monte Carlo analysis aimed at enhancing the mode overlap within the gain region. This adjustment enables the achievement of a laser emitting a 23-nm-wide spectrum while maintaining a defined 10 dB bandwidth for a pulse repetition rate of 3 GHz.

关键词： tunable amplifier mode

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2,2′-Biazulene diimide-based conjugate polymers for highperformance field-effect transistors

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Science China Chemistry 2018年第8期61卷 973-974页

作者： taku Shoji Shunji Ito Graduate School of Science and Technology Shinshu University Graduate School of Science and Technology Hirosaki University

Azulene,which is one of the non-alternating 10π-electron aromatic compounds,has attracted the interest of many research groups due to the application to material sciences utilizing the unique optoelectronic properties.

关键词： Th THF Biazulene diimide-based conjugate polymers for highperformance field-effect transistors PTB

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Phase transition in Pd_(40)Ni_(10)Cu_(30)P_(20) bulk metallic glass under HP & HT

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Science China(Physics,Mechanics & Astronomy) 2005年第6期48卷 716-722页

作者： Utsumi Wataru Okada taku Synchrotron Radiation Research Center Japan Atomic Energy Research Institute 1-1-1 Kout Mikasuki Sayo Hyogo 679-5148 Japan

The phase transitions in Pd40Ni10Cu30P20 bulk metallic glass (BMG) have been studied under high pressure and high temperature (HP & HT) by X-ray diffraction measurements with synchrotron radiation source. We found that the BMG underwent a phase transitions of amorphous-crystalline-amorphous at 10 GPa upon heating. The parallel experiments were carried out at 7 GPa, while we did not observe the amorphous-crystalline-amorphous transitions by increasing temperature. Quenching the melted BMG at 7 GPa, it was found that the phase crystallized from the melt differed from the primary phase crystallized from the starting amorphous solid upon heating, suggesting there existed a distinct mechanism in two cases.

关键词： phase transition, Pd40Ni10Cu30P20, high pressure and high temperature.

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Ab Initio Two-Phase Molecular Dynamics on the Melting Curve of SiO_2

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Journal of Earth Science 2010年第5期21卷 801-810页

作者： Yusuke Usui taku Tsuchiya Geodynamics Research Center Ehime University

Ab initio two-phase molecular dynamics simulations were performed on silica at pressures of 20-160 GPa and temperatures of 2 500-6 000 K to examine its solid-liquid phase boundary. Results indicate a melting temperature （Tin） of 5 900 K at 135 GPa. This is 1 100 K higher than the temperature considered for the core-mantle boundary （CMB） of about 3 800 K. The calculated melting temperature is fairly consistent with classical MD （molecular dynamics） simulations. For liquid silica, the O-O coordination number is found to be 12 along the Tm and is almost unchanged with increasing pressure. The self-diffusion coefficients of O and Si atoms are determined to be 1.3×10^-9-3.3×10^-9 m2/s, and the viscosity is 0.02-0.03 Pa＇s along the Tin. We find that these transport properties depend less on pressure in the wide range up of more than 135 GPa. The eutectic temperatures in the MgO-SiO2 systems were evaluated and found to be 700 K higher than the CMB temperature, though they would decrease considerably in more realistic mantle compositions.

关键词： Ab Initio Two-Phase Molecular Dynamics on the Melting Curve of SiO2 SiO CMB MgO than

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Base flow separation for soil erosion simulation in a granitic forested headwater catchment using a process-based model, GeoWEPP

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International Journal of Sediment Research 2023年第4期38卷 494-502页

作者： takuhei Yamasaki Shoichiro Hamamoto taku Nishimura The Graduate School of Agricultural and Life Sciences The University of Tokyo

Distributed erosion models, which simulate the physical processes of water flow and soil erosion, are effective for predicting soil erosion in forested catchments. Although subsurface flow through multiple pathways is dominant for runoff generation in forested headwater catchments, the process-based erosion model, Geo-spatial interface for Water Erosion Prediction Project(Geo WEPP), does not have an adequate subsurface component for the simulation of hillslope water flow. In the current study, the quick flow related to soil erosion during rainfall events is separated from the total hydrograph using base flow separation for Geo WEPP to use direct runoff to predict sediment discharge from a granitic-forested catchment in Japan. Water runoff and sediment discharge also are simulated using the conventional method that reproduces the total hydrograph, and the accuracy of the calculation and estimated erodibility parameters are evaluated. The proposed procedure reproduced the quick-flow runoff during rainfall and the cumulative sediment discharge from the catchment. Simultaneously, the proposed procedure overestimates water runoff during extreme weather events, such as typhoons. The estimated erodibility parameters for the hillslope soil were comparable to those of the surface soil in Japan using both the proposed procedure and the conventional one. Conversely, the channel erodibility obtained from the proposed procedure matched the observed sediment characteristics in the granitic forested catchment. The proposed procedure is a promising method to predict sediment discharge from forested catchments based on the geological features of the catchment.

关键词： Soil erosion Base flow separation GeoWEPP Headwater catchment Forest

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Expanding-contracting Earth

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Geoscience Frontiers 2013年第3期4卷 341-347页

作者： taku Tsuchiya Kenji Kawai Shigenori Maruyama Geodynamic Research Center Ehime UniversityMatsuyamaEhime 790-8577Japan Department of Earth and Planetary Sciences Tokyo Institute of TechnologyMeguroTokyo 152-8551Japan Department of Earth Science University of CaliforniaSanta Barbara 93106CAUSA

The Earth was born from a giant impact at 4.56 Ga. It is generally thought that the Earth subsequently cooled, and hence shrunk, over geologic time. However, if the Earth＇s convection was double-layered, there must have been a peak of expansion during uni-directional cooling. We computed the expansion- contraction effect using first principles mineral physics data. The result shows a radius about 120 km larger than that of the present Earth immediately after the consolidation of the magma-ocean on the surface, and subsequent shrinkage of about 110 km in radius within about 10 m.y., followed by gradual expansion of 11 km in radius due to radiogenic heating in the lower mantle in spite of cooling in the upper mantle in the Archean. This was due to double-layered convection in the Archean with final collapse of overturn with contraction of about g km in radius, presumably by the end of the Archean. Since then, the Earth has gradually cooled down to reduce its radius by around 12 km. Geologic evidence supports the late Archean mantle overturn ca. 2.6 Ga, such as the global distribution of super-liqnidus flood basalts on nearly all cratonic fragments （〉35 examples）. If our inference is correct, the surface environment of the Earth must have undergone extensive volcanism and emergence of local landmasses, because of the thin ocean cover （3-5 km thickness）. Global unconformity appeared in cratonic fragments with stromatolite back to 2.9 Ga with a peak at 2.6 Ga. The global magmatism brought extensive crustal melting to yield explosive felsic volcanism to transport volcanic ash into the stratosphere during the catastrophic mantle overturn. This event seems to be recorded by sulfur mass-independent fractionation （SMIF） at 2.6 Ga. During the mantle overturn, a number of mantle plumes penetrated into the upper mantle and caused local upward doming of by ca. 2-3 km which raised local landmasses above sea-level. The consequent increase of atmospheric oxygen enabled life evolutio

关键词： Mantle overturn Expanding Earth Global unconformity Nutrients Eukaryotes

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Woody plant cell walls:Fundamentals and utilization

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Molecular Plant 2024年第1期17卷 112-140页

作者： Wei Li Ying-Chung Jimmy Lin Ying-Lan Chen Chenguang Zhou Shuang Li Nette De Ridder Dyoni M.Oliveira Lanjun Zhange Baocai Zhang Jack P.Wang Changzheng Xu Xiaokang Fu Keming Luo Ai-Min Wu taku Demura Meng-Zhu Lu Yihua Zhou Laigeng Li Toshiaki Umezawa Wout Boerjan Vincent L.Chiang State Key Laboratory of Tree Genetics and Breeding Northeast Forestry UniversityHarbin 150040China Department of Life Science National Taiwan UniversityTaipeiTaiwanChina Department of Biotechnology and Bioindustry Sciences College of Bioscience and BiotechnologyNational Cheng Kung UniversityTainanTaiwanChina Department of Plant Biotechnology and Bioinformatics Ghent UniversityTechnologiepark 719052 GhentBelgium VIB Center for Plant Systems Biology Technologiepark 719052 GhentBelgium State Key Laboratory of Plant Genomics Insttute of Genetics and Developmental Biology Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Forest Biotechnology Group Department of Forestry and Environmental ResourcesNorth Carolina State UniversityRaleighNC 27695USA Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation Integrative Science Center of Germplasm CreationSchool of Life SciencesSouthwest UniversityChongqing 400715China Guangdong Key Laboratory for Innovative Developmentand Utilization of Forest Plant Germplasm College of Forestry and Landscape ArchitecturesSouth China Agricultural UniversityGuangzhou510642China Center for Digital Green-innovation Nara Institute of Science and TechnologykomaNara 630-0192Japan State Key Laboratory of Subtropical Siviculture College of Forestry and BiotechnologyZhejang A&F UniversityHangzhou 311300China CAS Center for Excellence in Molecular Plant Sciences Chinese Academy of Sciences300 Fenglin RoadShanghai 200032China Laboratoryof MetabolicScienceofForest Plants and Microorganisms Rsearch Institute for Sustainable HumanosphereKyoto UniversityUjiKyoto 611-0011 Japan

Cell walls in plants,particularly forest trees,are the major carbon sink of the terrestrial *** and biosynthetic features of plant cell walls were revealed early on,focusing mostly on herbaceous model *** developments in genomics,transcriptomics,epigenomics,transgenesis,and associated analytical techniques are enabling novel insights into formation of woody cell ***,we review multilevel regulation of cell wall biosynthesis in forest tree *** highlight current approaches to engineering cell walls as potential feedstock for materials and energy and survey reported field tests of such engineered transgenic *** outline opportunities and challenges in future research to better understand cell type biogenesis for more efficient wood cell wall modification and utilization for biomaterials or for enhanced carbon capture and storage.

关键词： regulation of cell wall formation biosynthesis of cell wall components lignin cellulose hemicellulose cell wall utilization

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The second continent:Existence of granitic continental materials around the bottom of the mantle transition zone

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Geoscience Frontiers 2013年第1期4卷 1-6页

作者： Kenji Kawai Shinji Yamamoto taku Tsuchiya Shigenori Maruyama Department of Earth Science University of CaliforniaSanta BarbaraCA 93106USA Department of Earth and Planetary Sciences Tokyo Institute of TechnologyOokayama 2-12-1MeguroTokyo 152-8551Japan Department of Earth and Planetary Sciences Tokyo Institute of TechnologyOokayama 2-12-1MeguroTokyo 152-8551.Japan Department of Earth Science and Astronomy Graduate School of Arts and SciencesThe University of TokyoKomaba 3-8-1MeguroTokyo 153-8902Japan Geodynamics Research Center Ehime University.Bunkyo-cho 2-5MatsuyamaEhime 790-8577Japan

It has been thought that granitic crust, having been formed on the surface, must have survived through the Earth＇s evolution because of its buoyancy. At subduction zones continental crust is predominantly created by arc magmatism and is returned to the mantle via sediment subduction, subduction erosion, and continental subduction. Granitic rocks, the major constituent of the continental crust, are lighter than the mantle at depths shallower than 270 km, but we show here, based on first principles calcu- lations, that beneath 270 km they have negative buoyancy compared to the surrounding material in the upper mantle and transition zone, and thus can be subducted in the depth range of 270-660 km. This suggests that there can be two reservoirs of granitic material in the Earth, one on the surface and the other at the base of the mantle transition zone （MTZ）. The accumulated volume of subducted granitic material at the base of the MTZ might amount to about six times the present volume of the continental crust. Our calculations also show that the seismic velocities of granitic material in the depth range from 270 to 660 km are faster than those of the surrounding mantle. This could explain the anomalous seismic-wave velocities observed around 660 km depth. The observed seismic scatterers and reported splitting of the 660 km discontinuity could be due to jadeite dissociation, chemical discontinuities between granitic material and the surrounding mantle, or a combination thereof.

关键词： Continental growthGraniteFirst principlesMantle transition zoneTectonicsGeodynamics

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Microstructure and mechanical properties of ZrO_2(Y_2O_3)-Al_2O_3 nanocomposites prepared by spark plasma sintering

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Particuology 2012年第3期10卷 345-351页

作者： Shufeng Li Hiroshi Izui Michiharu Okano Weihua Zhang taku Watanabe College of Science and Technology Nihon University7-24-1NarashinodaiFunabashiChiba 274-8501Japan College of Science and Technology Nihon University1-8-14KandasurugadaiChiyoda.Tokyo 101-8308Japan College of Materials Science and Technology Xi'an University of Technology5 SouthJinhua RoadXi'anShaanxi 710048China

Zirconia （yttria）-alumina ceramic nanocomposites were fabricated from different powders by spark plasma sintering （SPS）. One powder was a commercially available nanocomposite powder TZP-3Y2OA, consisting of 3 mol% yttria-stabilized zirconia （3-YSZ） reinforced with 20wt% alumina, and the other, used as a comparison, was a conventional mechanically mixed powder 3YSZ-2OA, a blend made of 3 mol% yttria-stabilized zirconia powder ZrO2 （3Y） and 20 wt% ,x-alumina powder. The effect of the sintering temperature on the densification, the sintering behavior, the mechanical properties and the microstructure of the composites was investigated. The results showed that the density increased with increasing sintering temperature, and thus, the mechanical properties were strengthened because of the increased densification. The nanocomposite powder TZP-3Y20A was easily sintered, and good mechanical properties were achieved as compared with the powder from the conventional mechanically mixed method, the maximum flexural strength and fracture toughness of which were 967 MPa and 5.27 MPa m 1/2, respectively.

关键词： Zirconia-aluminaNanocompositeSpark plasma sintering (SPS)Mechanical propertiesMicrohardnessFracture toughnessDensification

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