scholarly journals Comparison of the Floristic Composition and Diversity of Two Wetlands in Ethiopian

2021 ◽  
Author(s):  
Admasu Moges ◽  
Abyot Dibaba
Keyword(s):  
Aquatic Plants ◽  
Competitive Exclusion ◽  
Floristic Composition ◽  
Alpha Diversity ◽  
Diversity Indices ◽  
Ex Situ ◽  
Annual Plants ◽  
Strategic Plans ◽  
Total Species

Abstract The main purpose of this study was to determine and compare the floristic composition and diversity indices of Washa and Borale Wetlands, located in Central Ethiopian. As revealed in the result, 74 species belonging to 26 families, and 57 genera were identified. Asteraceae and Poaceae were the most dominant families contributing 24.56% and 14.04% to the total genera, and 20.27% and 16.22% to the total species identified, respectively. Of the total, about 92% plant species were herbs, whereas 1% was climber, the least one. The alpha diversity of the Washa and Borale wetlands were 51 and 64, respectively. The average richness of the Washa and Borale wetlands were 12.3 ±0.91, and 15.35 ± 0.89, respectively. Likewise, the Shannon diversity (H’) and evenness (E) of Washa and Borale sites were 2.24 and 0.87, and 2.67 and 0.97 respectively. Accordingly, based on their average values, the diversity, evenness and richness indices were higher in Borale than Washa sites, and showed significance difference between the two wetlands (P < 0.05). Likewise, in both sites, especially in Borale, the majority of the species were native, annual and upland, implying the suitability of the wetlands to these native, but to annual and upland invaders due to the ecological and hydrological modifications of the wetlands, and competitive exclusion of the native aquatic plants by upland annual plants. Generally, many of the wetlands’ species were annual and upland invaders. Hence, in-situ and ex-situ strategic plans are required for restoring the wetlands via giving priority.

scholarly journals Preliminary taxonomic survey of aquatic plants of Feni district, Bangladesh

2020 ◽  
Vol 27 (1) ◽  
pp. 103-111
Author(s):  
Mohammad Zashim Uddin ◽  
Joton Chandra Pal
Keyword(s):  
Plant Species ◽  
Aquatic Plants ◽  
Aquatic Plant ◽  
Ex Situ Conservation ◽  
Ex Situ ◽  
Plant Taxon ◽  
Oenanthe Javanica ◽  
Ecological Habitats ◽  
Good Number

Preliminary taxonomic survey of aquatic plants of Feni district was conducted between July 2016 and June 2017. Traditional taxonomic techniques and random meander methods were applied to record and collect aquatic plant species. A total of 56 aquatic plant species under 29 families were recorded from Feni district. Ecological habitats of aquatic plant species showed variations. Among them, 30% species prefer to grow near the edge of water, 20% as rooted submerged, 18% as rooted emergent, 16% as free floating, 12% as rooted floating and 4% surface creeper in the aquatic habitat. The uses of aquatic plants were showed that 27% species were used as fodder, 14% as medicinal, 11% as vegetable, 11% as edible fruits, 5% as duck weeds, 2% as artifacts and 30% as others purposes in the study area. Abundance of aquatic plant species in the habitat was showed variations. Among them 9% was found very abundant, 30% found common and 61% found rare in the study area. Based on the field observations and discussion with local people we were able to identify a good number of threats to aquatic plants and also pointed out some conservation measures for them. It was seemed that the species Achyranthes aquatica (thuash), Oenanthe javanica (painnaadani), and Chumannianthus dichotomus (patipata) were found to be limited in distribution outside Feni. These rare species need to be given priority for in situ and ex situ conservation. Bangladesh J. Plant Taxon. 27(1): 103-111, 2020 (June)

scholarly journals Analysis of Structure and Diversity of the Kilengwe Forest in the Morogoro Region, Tanzania

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
David Sylvester Kacholi
Keyword(s):  
Species Abundance ◽  
Basal Area ◽  
Alpha Diversity ◽  
Wiener Index ◽  
Forest Degradation ◽  
Diversity Indices ◽  
Importance Value ◽  
Species Area ◽  
Total Species ◽  
Fisher’S Alpha

This study investigates the structure, species composition, and diversity of a section of the Kilengwe Forest in Tanzania. In order to accomplish the proposed objectives, 18 plots of 20 m × 20 m were randomly established in the forest and the number of tree species in each plot was identified and counted. The most important families and species were determined using importance value indices at the respective taxonomic levels. Diversity was measured using the Shannon-Wiener and Fisher alpha diversity indices. A total of 276 stems/ha representing 93 species/ha within 26 families were documented from 0.72 ha. Fabaceae and Julbernadia globiflora were the dominant family and species, respectively. Seventy-eight percent of the total species were rare. The average basal area of the forest was 7.1 m2/ha. The Shannon-Wiener index (4.02) and Fisher’s alpha diversity (35.5) indicated high species diversity within the forest. The species-area and species-abundance curves revealed an escalating trend implying that more sampling efforts could result in a higher number of species existing in the forest. The size class distribution displayed a reverse J-shaped pattern; however, the larger size classes DBH >50 cm were not represented. The study suggests the necessity for anthropogenic disturbance control as this is the major source of forest degradation in the studied area.

scholarly journals Structure and floristic composition associated with an endangered species Beta patula Aiton (Amaranthaceae) in the Islands of Madeira Archipelago

2021 ◽  
Vol 9 ◽  
Author(s):  
Humberto Nóbrega ◽  
Gregório Freitas ◽  
M. A. Zavattieri ◽  
Carla Ragonezi ◽  
Miguel Pinheiro de Carvalho
Keyword(s):  
Endangered Species ◽  
Plant Genetic Resources ◽  
Floristic Composition ◽  
Crop Wild Relatives ◽  
Ex Situ ◽  
Crop Species ◽  
Life Project ◽  
Madeira Archipelago ◽  
Management Protocol

Twenty-two native Crop Wild Relatives (CWR) occur in specific dry environments of Madeira Archipelago, like Desembarcadouro islet in Ponta de São Lourenço and Chão islet in Desertas Islands. Nine of them share the same gene pool with crop species included in Annex I of the International Treaty on Plant Genetic Resources for Food and Agriculture. Amongst them, Beta patula Aiton, an IUCN Critically Endangered species, has been studied in detail for in situ and ex situ conservation. The present paper summarises the information recorded during the Beta patula population assessment. Valuable information on plant communities associated with this species was obtained. The data provides information of a vegetation census spanning 7 years, from 2014 to 2020, in two uninhabited islets where Beta patula occurs, Desembarcadouro and Chão islets. The collected dataset consists of 1,786 vegetation descriptions, where 31 species were recorded. All generated data have been published and will be used towards the implementation of conservation actions and to establish a middle term management protocol for Beta patula and other CWR in situ conservation in the framework of a genetic reserve. This work is part of a EU LIFE Project, LIFE RECOVER NATURA and was conducted by members of the ISOPlexis Center, University of Madeira.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

The use of transmission and analytical electron microscopy in studying reactions and phase transformations in thin film

1993 ◽  
Vol 51 ◽  
pp. 842-843
Author(s):  
K. Barmak
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transformations ◽  
Analytical Electron Microscopy ◽  
Ex Situ ◽  
Multilayer Thin Films ◽  
Absolute Concentration ◽  
Analytical Electron ◽  
Deposition Step

Generally, processing of thin films involves several annealing steps in addition to the deposition step. During the annealing steps, diffusion, transformations and reactions take place. In this paper, examples of the use of TEM and AEM for ex situ and in situ studies of reactions and phase transformations in thin films will be presented.The ex situ studies were carried out on Nb/Al multilayer thin films annealed to different stages of reaction. Figure 1 shows a multilayer with dNb = 383 and dAl = 117 nm annealed at 750°C for 4 hours. As can be seen in the micrograph, there are four phases, Nb/Nb3-xAl/Nb2-xAl/NbAl3, present in the film at this stage of the reaction. The composition of each of the four regions marked 1-4 was obtained by EDX analysis. The absolute concentration in each region could not be determined due to the lack of thickness and geometry parameters that were required to make the necessary absorption and fluorescence corrections.

Transmission Electron Microscopy of Epitaxial silicides grown by ultra high vacuum deposition

1989 ◽  
Vol 47 ◽  
pp. 462-463
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Transmission Electron

The silicides CoSi2 and NiSi2 are both metallic with the fee flourite structure and lattice constants which are close to silicon (1.2% and 0.6% smaller at room temperature respectively) Consequently epitaxial cobalt and nickel disilicide can be grown on silicon. If these layers are formed by ultra high vacuum (UHV) deposition (also known as molecular beam epitaxy or MBE) their thickness can be controlled to within a few monolayers. Such ultrathin metal/silicon systems have many potential applications: for example electronic devices based on ballistic transport. They also provide a model system to study the properties of heterointerfaces. In this work we will discuss results obtained using in situ and ex situ transmission electron microscopy (TEM).In situ TEM is suited to the study of MBE growth for several reasons. It offers high spatial resolution and the ability to penetrate many monolayers of material. This is in contrast to the techniques which are usually employed for in situ measurements in MBE, for example low energy electron diffraction (LEED) and reflection high energy electron diffraction (RHEED), which are both sensitive to only a few monolayers at the surface.

Atomic Layer Deposition of LiF and Lithium Ion Conducting (AlF3)(LiF)x Alloys Using Trimethylaluminum, Lithium Hexamethyldisilazide and Hydrogen Fluoride

2017 ◽  
Author(s):  
Younghee Lee ◽  
Daniela M. Piper ◽  
Andrew S. Cavanagh ◽  
Matthias J. Young ◽  
Se-Hee Lee ◽  
...  
Keyword(s):  
Lithium Ion ◽  
Atomic Layer ◽  
Mass Gain ◽  
Alloy Film ◽  
Ex Situ ◽  
X Ray ◽  
Layer Deposition ◽  
Ion Conducting ◽  
Good Agreement

<div>Atomic layer deposition (ALD) of LiF and lithium ion conducting (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloys was developed using trimethylaluminum, lithium hexamethyldisilazide (LiHMDS) and hydrogen fluoride derived from HF-pyridine solution. ALD of LiF was studied using in situ quartz crystal microbalance (QCM) and in situ quadrupole mass spectrometer (QMS) at reaction temperatures between 125°C and 250°C. A mass gain per cycle of 12 ng/(cm<sup>2</sup> cycle) was obtained from QCM measurements at 150°C and decreased at higher temperatures. QMS detected FSi(CH<sub>3</sub>)<sub>3</sub> as a reaction byproduct instead of HMDS at 150°C. LiF ALD showed self-limiting behavior. Ex situ measurements using X-ray reflectivity (XRR) and spectroscopic ellipsometry (SE) showed a growth rate of 0.5-0.6 Å/cycle, in good agreement with the in situ QCM measurements.</div><div>ALD of lithium ion conducting (AlF3)(LiF)x alloys was also demonstrated using in situ QCM and in situ QMS at reaction temperatures at 150°C A mass gain per sequence of 22 ng/(cm<sup>2</sup> cycle) was obtained from QCM measurements at 150°C. Ex situ measurements using XRR and SE showed a linear growth rate of 0.9 Å/sequence, in good agreement with the in situ QCM measurements. Stoichiometry between AlF<sub>3</sub> and LiF by QCM experiment was calculated to 1:2.8. XPS showed LiF film consist of lithium and fluorine. XPS also showed (AlF<sub>3</sub>)(LiF)x alloy consists of aluminum, lithium and fluorine. Carbon, oxygen, and nitrogen impurities were both below the detection limit of XPS. Grazing incidence X-ray diffraction (GIXRD) observed that LiF and (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film have crystalline structures. Inductively coupled plasma mass spectrometry (ICP-MS) and ionic chromatography revealed atomic ratio of Li:F=1:1.1 and Al:Li:F=1:2.7: 5.4 for (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film. These atomic ratios were consistent with the calculation from QCM experiments. Finally, lithium ion conductivity (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film was measured as σ = 7.5 × 10<sup>-6</sup> S/cm.</div>

A New Method of Wafer Level Plan View TEM Sample Preparation by DualBeam

2008 ◽  
Author(s):  
Hyoung H. Kang ◽  
Michael A. Gribelyuk ◽  
Oliver D. Patterson ◽  
Steven B. Herschbein ◽  
Corey Senowitz
Keyword(s):  
Sample Preparation ◽  
Ex Situ ◽  
Wafer Level ◽  
Cross Sectional ◽  
Plan View ◽  
Manufacturing Line ◽  
Transmission Electron ◽  
Thin Lamella ◽  
Preparation Techniques

Abstract Cross-sectional style transmission electron microscopy (TEM) sample preparation techniques by DualBeam (SEM/FIB) systems are widely used in both laboratory and manufacturing lines with either in-situ or ex-situ lift out methods. By contrast, however, the plan view TEM sample has only been prepared in the laboratory environment, and only after breaking the wafer. This paper introduces a novel methodology for in-line, plan view TEM sample preparation at the 300mm wafer level that does not require breaking the wafer. It also presents the benefit of the technique on electrically short defects. The methodology of thin lamella TEM sample preparation for plan view work in two different tool configurations is also presented. The detailed procedure of thin lamella sample preparation is also described. In-line, full wafer plan view (S)TEM provides a quick turn around solution for defect analysis in the manufacturing line.

PROPUESTA DE CONSERVACIÓN DE TRES ESPECIES MEXICANAS DE PICEA EN PELIGRO DE EXTINCIÓN

2015 ◽  
Vol 38 (3) ◽  
pp. 235 ◽  
Author(s):  
Eduardo Mendoza-Maya ◽  
Judith Espino-Espino ◽  
Carmen Z. Quiñones-Pérez ◽  
Celestino Flores-López ◽  
Christian Wehenkel ◽  
...  
Keyword(s):  
Ex Situ

Picea mexicana Martínez, P. chihuahuana Martínez y P. martinezii Patterson son especies endémicas de México en peligro de extinción. Se presenta una síntesis de su situación actual y una propuesta de manejo para su conservación in situ y ex situ, con base en la diversidad y estructura genética de las poblaciones y la ubicación de las áreas en donde se predice existirá el hábitat climático que les es propicio en el futuro (años 2030, 2060 y 2090; al promediar los modelos Canadiense, Hadley y Geofísica de Fluidos con escenarios de emisiones A y B). Para la conservación in situ se plantea la protección, el incremento de la diversidad genética y la expansión de las tres únicas poblaciones de P. mexicana, las cuatro únicas de P. martinezii y ocho poblaciones designadas prioritarias de las 40 poblaciones de P. chihuahuana, mediante la plantación de individuos originados de otras poblaciones hasta alcanzar un tamaño mínimo de población genéticamente viable (entre 1035 a 3836 individuos). Para la conservación ex situ se propone el establecimiento de poblaciones en sitios fuera del rango de distribución natural de las especies, en donde se ha proyectado que ocurrirá el clima que les es propicio, con al menos 3606 individuos de P. mexicana en el volcán Cofre de Perote, Veracruz; 2431 individuos de P. chihuahuana en el municipio de Guanaceví, Durango; y 3092 individuos de P. martinezii en la región de Tlatlauquitepec, Puebla, con plantas originadas de una mezcla de semillas colectadas de árboles al azar de poblaciones específicas.

scholarly journals Hot Workability of 300M Steel Investigated by In Situ and Ex Situ Compression Tests

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 880 ◽  
Author(s):  
Rongchuang Chen ◽  
Haifeng Xiao ◽  
Min Wang ◽  
Jianjun Li
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Hot Working ◽  
Ex Situ ◽  
Lower Strain Rate ◽  
Hot Workability ◽  
Compression Tests ◽  
300M Steel ◽  
Lower Strain

In this work, hot compression experiments of 300M steel were performed at 900–1150 °C and 0.01–10 s−1. The relation of flow stress and microstructure evolution was analyzed. The intriguing finding was that at a lower strain rate (0.01 s−1), the flow stress curves were single-peaked, while at a higher strain rate (10 s−1), no peak occurred. Metallographic observation results revealed the phenomenon was because dynamic recrystallization was more complete at a lower strain rate. In situ compression tests were carried out to compare with the results by ex situ compression tests. Hot working maps representing the influences of strains, strain rates, and temperatures were established. It was found that the power dissipation coefficient was not only related to the recrystallized grain size but was also related to the volume fraction of recrystallized grains. The optimal hot working parameters were suggested. This work provides comprehensive understanding of the hot workability of 300M steel in thermal compression.

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