scholarly journals Diversité Floristique Et Structurale De Deux Forêts Communautaires Sous Exploitation Au Cameroun: Cas De Kompia Et Nkolenyeng

2018 ◽  
Vol 14 (24) ◽  
pp. 245
Author(s):  
Kengne Olivier Clovis ◽  
Zapfack Louis ◽  
Garcia Claude ◽  
Noiha Noumi Valery ◽  
Nkongmeneck Bernard-Aloys
Keyword(s):  
Local Development ◽  
Diversity Index ◽  
Anthropogenic Activities ◽  
Large Diameter ◽  
Small Diameter ◽  
Basal Area ◽  
Canopy Height ◽  
Plant Biodiversity ◽  
Plant Structure ◽  
Community Forests

The attribution of community forests to local populations has emerged as a new participative management system of plant biodiversity in Cameroon. Further to the intensification of anthropogenic activities in these forests, the logging impact on this biodiversity remains poorly known. This study was conducted in two different community forests located in the Kompia and Nkolenyeng villages, respectively. It aims to provide information on the state of the flora and plant structure of the community forests subjected to logging activities. Floristic inventories were carried out in nine biotope types using the variable-area sampling method. A total of 2772 individuals with dbh ≥ 10 cm were recorded in the community forests. In the whole biotopes, the species richness ranges from 19 to 98 species, the Shannon diversity index from 3.63 to 5.99 and the Pielou evenness from 0.65 to 0.93. The density of trees ranges from 73 ± 27 to 661 ± 119 stems ha-1 , the basal area from 15.68 ± 13.14 to 70.05 ± 28.76 m² ha-1 , the mean diameter of 18.85 ± 4.80 to 57.39 ± 20.70 cm and the canopy height from 12.26 ± 1.22 to 25.18 ± 1.02 m, on the average between biotopes. The two community forests showed decrease in tree density, a proliferation of the pioneer species, increase of small-diameter light-demanding species, a scarcity of large-diameter trees, and lowering of canopy height. These changes could compromise the sustainable management of these forests and their ability to ensure long-term local development. The large number of useful species identified in the two community forests is a reason to reinforce the preservation and management measures of the plant biodiversity of these forest areas.

scholarly journals A Simple Conservation Tool to Aid Restoration of Amphibians following High-Severity Wildfires: Use of PVC Pipes by Green Tree Frogs (Hyla cinerea) in Central Texas, USA

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 649
Author(s):  
Thanchira Suriyamongkol ◽  
Kaitlyn Forks ◽  
Andrea Villamizar-Gomez ◽  
Hsiao-Hsuan Wang ◽  
William E. Grant ◽  
...  
Keyword(s):  
Anthropogenic Activities ◽  
Large Diameter ◽  
Small Diameter ◽  
Iucn Red List ◽  
Tree Frog ◽  
Hyla Cinerea ◽  
High Severity ◽  
Central Texas ◽  
Tree Frogs ◽  
Pipe Size

Amphibians are the most threatened vertebrate class based on the IUCN Red List. Their decline has been linked to anthropogenic activities, with wildfires being among the most conspicuous agents of habitat alterations affecting native amphibians. In 2011, the most destructive wildfire in Texas history occurred in the Lost Pines ecoregion of central Texas, USA, burning 39% of the 34,400 ha forest and drastically decreasing available habitats for many native wildlife species, including the green tree frog (Hyla cinerea). We investigated use of PVC pipes as artificial refuges for green tree frogs in different habitats within this post-fire pine forest. We monitored green tree frog use of small (diameter 38.1-mm, 1.5 inch) and large (diameter 50.8-mm, 2 inch) pipes located adjacent to, and 5 m from, ponds in burned and unburned areas over a 5-month period. We caught 227 frogs, 101 (24 adults and 77 juveniles) in burned and 126 (61 adults, 63 juveniles, and 2 unknown) in unburned areas. A relationship between pipe use by adults and/or juveniles and pipe location in burned versus unburned areas was found, but pipe use by adults and/or juveniles and pipe size were independent. Pipe use by adults and/or juveniles and pipe size were also independent. Juveniles were more frequently observed in pipes located adjacent to ponds. Our results confirmed that PVC pipes merit consideration as a simple, inexpensive, conservation tool to aid in restoration of green tree frog populations after high-severity wildfires. Such artificial refuges may be particularly important for survival of juveniles in severely altered post-fire habitats.

scholarly journals Ecological Structure of a Tropical Urban Forest in Bang Kachao Peninsula, Bangkok

2017 ◽  
Author(s):  
Montathip Sommeechai ◽  
Chongrak Wachrinrat ◽  
Dell Bernard ◽  
Nipon Thangtam ◽  
Jamroon Srichaichana
Keyword(s):  
Satellite Images ◽  
Urban Forest ◽  
Forest Type ◽  
Diversity Index ◽  
Basal Area ◽  
Home Garden ◽  
Mangrove Forests ◽  
Plant Structure ◽  
Rapid Urbanization ◽  
Ecological Structure

Rapid urbanization has changed the structure and function of natural ecosystems, especially the floodplain ecosystems in SE Asia. This paper describes the ecological structure of vegetation stands and the usefulness of satellite images to characterize a disturbed tropical urban forest located in the lower floodplain of the Chao Phraya River, Thailand. Nine representative plots were established in Bang Kachao peninsula in 4 tropical urban forest types: rehabilitation forest, home-garden agroforestry, mangrove and park. The correlation between NDVI and LAI obtained from satellite images and plant structure from field surveys were analyzed. The NDVI had the highest relationship with stand factors for the number of families, number of species, Shannon-Weiner’s diversity index and total basal area. The LAI had the highest correlation with total basal area, number of canopy layers, stand density and canopy density. Linear regression predicted the correlation between NDVI and LAI with stand factors as show above. The trend in NDVI and LAI reflected the urban forest type, being high in rehabilitation and mangrove forests, moderate in home-gardens and low in parks. Future urban planning of the Bang Kachao peninsula should focus on rehabilitation to increase the biodiversity and complexity of the urban forest.

scholarly journals The Effects of Landscape Change on Plant Diversity and Structure in the Bale Mountains National Park, Southeastern Ethiopia

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Annissa Muhammed ◽  
Eyasu Elias
Keyword(s):  
Species Richness ◽  
Landscape Change ◽  
National Park ◽  
Diversity Index ◽  
Anthropogenic Activities ◽  
Sustainable Use ◽  
Basal Area ◽  
Floristic Composition ◽  
Woody Species ◽  
Economic Benefits

Bale Mountains National Park is one of the protected areas in Ethiopia that holds the largest area of Afroalpine habitat in Africa and the second largest stand of moist tropical forest. Nevertheless, human settlements, overgrazing, and recurrent fire are the main problems in the park. This study aimed to determine the effects of human-induced landscape change in floristic composition and structure in the park. The vegetation data were collected systematically from 96 sample plots laid along 24 line transects in the edge and interior habitats of the six land cover types. Vegetation composition and landscape structural analysis were made using R software version 3.5.2 and FRAGSTATS version 4.2.1, respectively. Patch number was strong and positively affected species richness (r = −0.90, p < 0.05 ), diversity (r = −0.96, p < 0.01 ), and basal area (r = −0.96, p < 0.001 ), whereas mean patch size was strong and negatively influenced species richness (r = 0.95, p < 0.05 ), diversity (r = 0.87, p < 0.05 ), and basal area (r = 0.82, p < 0.05 ). The overall species richness, Shannon diversity index, and Margalef index were significantly higher in the edge habitat; however, the mean basal area of woody species was significantly higher in the interior habitat at p < 0.05 . This study uncovered that the park is floristically rich and diverse, and it provides a variety of ecological and economic benefits to the surrounding community and to the nation at large. However, these benefits are gradually declining due to the high level of anthropogenic activities in the park. Thus, integrated environmental management strategy that blends with sustainable use of natural resources should be implemented to minimize the threats.

Floristic Variation of Tree Communities and Their Association with Soil Properties in Pulau Jerejak, Penang, Peninsular Malaysia

2020 ◽  
Vol 14 (1) ◽  
pp. 34
Author(s):  
Faezah Pardi
Keyword(s):  
Tree Species ◽  
Diversity Index ◽  
Basal Area ◽  
Peninsular Malaysia ◽  
Importance Value ◽  
Conservation Action ◽  
Endangered Tree ◽  
Endangered Tree Species ◽  
Tree Communities ◽  
Floristic Variation

This study was conducted at Pulau Jerejak, Penang to determine the floristic variation of its tree communities. A 0.5-hectare study plot was established and divided into 11 subplots. A total of 587 trees with diameter at breast height (DBH) of 5 cm and above were measured, identified and recorded. The tree communities comprised of 84 species, 63 genera and 32 families. The Myrtaceae was the most speciose family with 10 recorded species while Syzgium glaucum (Myrtaceae) was the most frequent species. The Myrtaceae recorded the highest density of 306 individuals while Syzgium glaucum (Myrtaceae) had the highest species density of 182 individuals. Total tree basal area (BA) was 21.47 m2/ha and family with the highest BA was Myrtaceae with 5.81 m2/ha while at species level, Syzgium glaucum (Myrtaceae) was the species with the highest total BA in the plot with value of 4.95 m2/ha. The Shannon˗Weiner Diversity Index of tree communities showed a value of 3.60 (H'max = 4.43) and Evenness Index of 0.81 which indicates high uniformity of tree species. The Margalef Richness Index (R') revealed that the tree species richness was 13.02. Myrtaceae had the highest Importance Value of 20.4%. The Canonical Correspondence Analysis (CCA) showed that Diospyros buxifolia (Ebenaceae) and Pouteria malaccensis (Sapotaceae) were strongly correlated to low pH. Dysoxylum cauliflorum (Meliaceae) and Eriobotrya bengalensis (Rosaceae) were correlated to phosphorus (P) and calcium ion (Ca2+), respectively. Therefore, the trees species composition at Pulau Jerejak showed that the biodiversity is high and conservation action should be implemented to protect endangered tree species. Keywords: Floristic variation; Tree communities; Trees composition; Pulau Jerejak; Species diversity

Differences in the brain stem terminations of large- and small-diameter vestibular primary afferents

1995 ◽  
Vol 74 (3) ◽  
pp. 1362-1366 ◽  
Author(s):  
J. A. Huwe ◽  
E. H. Peterson
Keyword(s):  
Brain Stem ◽  
Large Diameter ◽  
Small Diameter ◽  
Movement Control ◽  
Three Dimensions ◽  
Significant Shift ◽  
Axon Diameter ◽  
Vestibular Complex ◽  
The Brain ◽  
Adjacent Brain

1. We visualized the central axons of 32 vestibular afferents from the posterior canal by extracellular application of horseradish peroxidase, reconstructed them in three dimensions, and quantified their morphology. Here we compare the descending limbs of central axons that differ in parent axon diameter. 2. The brain stem distribution of descending limb terminals (collaterals and associated varicosities) varies systematically with parent axon diameter. Large-diameter afferents concentrate their terminals in rostral regions of the medial/descending nuclei. As axon diameter decreases, there is a significant shift of terminal concentration toward the caudal vestibular complex and adjacent brain stem. 3. Rostral and caudal regions of the medial/descending nuclei have different labyrinthine, cerebellar, intrinsic, commissural, and spinal connections; they are believed to play different roles in head movement control. Our data help clarify the functions of large- and small-diameter afferents by showing that they contribute differentially to rostral and caudal vestibular complex.

scholarly journals Elastic Modulus and Elasticity Ratio of Malignant Breast Lesions with Shear Wave Ultrasound Elastography: Variations with Different Region of Interest and Lesion Size

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1015
Author(s):  
Antonio Bulum ◽  
Gordana Ivanac ◽  
Eugen Divjak ◽  
Iva Biondić Špoljar ◽  
Martina Džoić Dominković ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Shear Wave ◽  
Large Diameter ◽  
Small Diameter ◽  
Shear Wave Elastography ◽  
Lesion Size ◽  
Ultrasound Elastography ◽  
Breast Lesions ◽  
Malignant Breast ◽  
The Impact

Shear wave elastography (SWE) is a type of ultrasound elastography with which the elastic properties of breast tissues can be quantitatively assessed. The purpose of this study was to determine the impact of different regions of interest (ROI) and lesion size on the performance of SWE in differentiating malignant breast lesions. The study included 150 female patients with histopathologically confirmed malignant breast lesions. Minimal (Emin), mean (Emean), maximal (Emax) elastic modulus and elasticity ratio (e-ratio) values were measured using a circular ROI size of 2, 4 and 6 mm diameters and the lesions were divided into large (diameter ≥ 15 mm) and small (diameter < 15 mm). Highest Emin, Emean and e-ratio values and lowest variability were observed when using the 2 mm ROI. Emax values did not differ between different ROI sizes. Larger lesions had significantly higher Emean and Emax values, but there was no difference in e-ratio values between lesions of different sizes. In conclusion, when measuring the Emin, Emean and e-ratio of malignant breast lesions using SWE the smallest possible ROI size should be used regardless of lesion size. ROI size has no impact on Emax values while lesion size has no impact on e-ratio values.

Analysis Influence of Pile Embedded Depth and Diameter on Pile Tip Resistance

2013 ◽  
Vol 353-356 ◽  
pp. 459-462
Author(s):  
Ying Jie Zheng ◽  
Bin Fang ◽  
Lian Xiang Li
Keyword(s):  
Large Diameter ◽  
Small Diameter ◽  
Stiffness Ratio ◽  
Initial Stiffness ◽  
Tip Resistance

Pile tip absolute settlement curves and relative settlement curves of several working cases were analyzed. It is found that load-settlement curve characteristic related to the selection standard. The tip resistance initial stiffness of each case was analyzed. Results show that the small diameter pile has higher initial stiffness than large diameter pile, embedded depth has little influence on initial stiffness ratio, but increment of initial stiffness is linear with embedded depth growth.

STRUCTURAL AND FLORISTIC CHARACTERIZATION OF THE OULED BECHIH FOREST (ALGERIA)

2021 ◽  
Author(s):  
Touafchia Boutheyna ◽  
Kadi Zahia ◽  
Redjaimia Lilia ◽  
Rached-Kanouni Malika
Keyword(s):  
Diversity Index ◽  
Basal Area ◽  
Woody Species ◽  
Quercus Suber ◽  
Average Density ◽  
Quercus Canariensis ◽  
Rational Management ◽  
Sustainable Conservation ◽  
Total Structure

The objective of this study is the rational management of forest ecosystems for sustainable conservation of floristic biodiversity. Two types of analysis are carried out: structural analysis and analysis of the main species. A total of 22 families were identified, divided among 32 species. The dominant woody species are Quercus suber and Quercus canariensis. Fagaceae is the most represented family. The average values of species richness and Shannon diversity index are 4 ± 1.8 and 0.9 ± 0.30 species/plot respectively. The average density of woody species in the Oueld Bechih forest was 158 ± 28 tree/ha with an average basal area of 32.67 ± 0.74m²/ha. The height structure shows that trees in height classes is ≥ 6 has very high density, evidence of almost no natural regeneration. The total structure indicates that larger trees are more abundant. In effect, this work provides a database for the forest, but it represents only one facet to be considered in protecting and restoring it.

New method of poultry selection

2021 ◽  
pp. 61-66
Author(s):  
E. Rehleckaya ◽  
A. Dymkov ◽  
L. Lazarets ◽  
A. Maltsev
Keyword(s):  
Egg Production ◽  
Initial Period ◽  
Large Diameter ◽  
Small Diameter ◽  
Live Weight ◽  
Individual Variability ◽  
Egg Laying ◽  
New Method ◽  
Egg Diameter ◽  
Correlation Rate

Purpose: Install the influence of the «small diameter of the egg» on the living mass and the reproductive qualities of chickens of meat crosses and the quail of meat breeds.Materials and methods. The selection was carried out along egg production and mass of eggs and additionally on the average small diameter of 5 eggs by value of ≥0.5σ from the average for the herd, while the evaluation on the basis of the «small diameter of the egg» was carried out in chickens aged 238 days of life, quails — 70 days of life. Calculated the average for each female and the average for the herd. For further reproduction, chickens carrying eggs with a small egg diameter ≥0.5σ from the average for the herd. Studies were held in SibNIP on quail and on the courses.Results. In the initial period of the egg laying, the individual variability of the small diameter of the egg — more than 10% (in the future, the figure decreased). The close correlation rate of the small egg diameter in the first half of the egg laying with such at the end of the bird's operation period was revealed. It has been established that the large diameter of the egg has a positive reliable connection with a lively mass, but negative with egg production. The reliable correlation rate of the small diameter of the egg with a live weight at a 42-day age, as well as with the derivation of eggs. The inheritance coefficients of the small diameter of the egg are comparable to the inheritance coefficients of the mass of eggs and significantly exceed those for a large diameter of the egg. The selection according to the small diameter of the eggs by ≥0.5σ from the average for the herd led to the fact that the chickens of the experimental groups reliably exceeded the live weight in the SB level of 1.57%, in the line G8 — by 1.35%. The superiority of a lively mass of quail of experienced groups was more pronounced than that of the chickens: the Pharaoh breed — by 4.15%, the Texas white breed is 4.22%. In relation to the derivation of eggs, a similar trend was traced. The derivation of eggs in quails of experienced groups was more than 4.59–4.98%; Country, respectively, 4.57–5.22%. Egg production of females of comparable groups of both chickens and quail was almost on the same level, and the difference was unreliable.Conclusion. It was established that a new method of breeding the poultry of the meat direction of productivity allows without decreasing egg production to increase the living mass of chickens of meat crosses by 1.5%, rewinds of meat breeds — by 4%, the derivation of eggs, respectively, by 4–5%. The method is intended for early prediction of females productivity during breeding selection.

Copolymer-Nanoparticles Mixture in a Cylindrical Pore

NANO ◽  
2017 ◽  
Vol 12 (04) ◽  
pp. 1750045
Author(s):  
Jun-Xing Pan ◽  
Yu-Qi Guo ◽  
Yu-Fang Han ◽  
Min-Na Sun ◽  
Jin-Jun Zhang
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
Polymer Nanocomposites ◽  
Diblock Copolymer ◽  
Large Diameter ◽  
Small Diameter ◽  
Confinement Effect ◽  
Cylindrical Pore ◽  
Disorder Phase Transition ◽  
Novel Structures

Computer simulation is carried out for investigating the effect of nanoparticles on diblock copolymer morphology under cylindrical confinement. The phase diagrams of polymer nanocomposites with nanoparticle-block wetting strength and concentration of nanoparticles are obtained in different nanopores. In small diameter nanopore, there is almost no influence of nanoparticles on the diblock copolymer morphology because of the stronger confinement effect; in middle diameter nanopore, the system can self-assemble into various novel structures due to the interaction between confinement effect and nanoparticles effect; in large diameter nanopore, due to the stronger effect of nanoparticles, a disorder-order-disorder phase transition occurs with the wetting strength and concentration of nanoparticles increasing. This result can be useful in designing new nanocomposites with advanced electrical conductivity and/or mechanical strength.

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