scholarly journals Kepadatan populasi POPULATION DENSITY OF EARTHWORMS IN A RUBBER PLANTATION IN THE SOUTHERN SECURAI VILLAGE, BATANG REJO SUB-VILLAGE, LANGKAT DISTRICT

Jurnal Jeumpa ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 478-482
Author(s):  
Sri Rahayu
Keyword(s):  
Population Density ◽  
Lumbricus Terrestris ◽  
Rubber Plantation ◽  
Hand Sorting

Cacing tanah merupakan salah satu kelompok dari makrofauna yang memainkan peranan penting diberbagai proses fisika, kimia ataupun biologi tanah. Keberadaan cacing tanah menjadi salah satu indikator dari keseburuan suatu tanah, karena melalui aktivitas dari cacing tanah tersebut dapat memperbaiki sifat fisik maupun kimia tanah. Tujuan dari penelitian ini untuk mengetahui kepadatan populasi cacing tanah(Lumbricus terrestris) dalam dua perlakuan, yang pertama yaitu pada jenis tanah organik dan jenis tanah non organik di perkebunan karet. Pengambilan sampel cacing tanah dengan metode hand sorting, dengan jumlah plot untuk pengambilan sampel yaitu 10 plot dengan ukuran 1x1m. Dari hasil penelitian diperoleh jumlah kepadatan populasi cacing tanah(Lumbricus terrestris) 13,00 individu/m2, yang dimana kepadatan populasi pada stasiun I (tanah organik) lebih tinggi yaitu 7,8 individu/m2  dibandingkan dengan stasiun II (tanah non organik) hanya memperoleh 5,8 individu/m2.

scholarly journals The Effect of Earthworm (Lumbricus terrestrisL.) Population Density and Soil Water Content Interactions on Nitrous Oxide Emissions from Agricultural Soils

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Andrew K. Evers ◽  
Tyler A. Demers ◽  
Andrew M. Gordon ◽  
Naresh V. Thevathasan
Keyword(s):  
Population Density ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Agricultural Soils ◽  
Lumbricus Terrestris ◽  
Nitrous Oxide Emissions ◽  
Research Station ◽  
Significant Difference ◽  
The Relationship

Earthworms may have an influence on the production ofN2O, a greenhouse gas, as a result of the ideal environment contained in their gut and casts for denitrifier bacteria. The objective of this study was to determine the relationship between earthworm (Lumbricus terrestrisL.) population density, soil water content andN2Oemissions in a controlled greenhouse experiment based on population densities (90 to 270 individualsm−2) found at the Guelph Agroforestry Research Station (GARS) from 1997 to 1998. An experiment conducted at considerably higher than normal densities of earthworms revealed a significant relationship between earthworm density, soil water content andN2Oemissions, with mean emissions increasing to 43.5 gha−1day−1at 30 earthworms 0.0333 m−2at 35% soil water content. However, a second experiment, based on the density of earthworms at GARS, found no significant difference inN2Oemissions (5.49 to 6.99 gha−1day−1) aa a result of density and 31% soil water content.

Environmental factors influencing immigration behaviour of the invasive earthworm Lumbricus terrestris

2013 ◽  
Vol 91 (12) ◽  
pp. 859-865 ◽  
Author(s):  
Michael J. McTavish ◽  
Nathan Basiliko ◽  
Tara E. Sackett
Keyword(s):  
Population Density ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Video Recording ◽  
Lumbricus Terrestris ◽  
Litter Type ◽  
Dispersal Patterns ◽  
Background Population ◽  
Significant Difference ◽  
Earthworm Lumbricus

Despite the ecological threats posed to northeastern North American forests by the invasive earthworm Lumbricus terrestris L., 1758 (Oligochaeta: Lumbricidae), the dispersal behaviour of this organism is poorly understood. This study investigated how environmental conditions influence the immigration behaviour of L. terrestris. Experimental mesocosms were used to test for differences in burrow establishment depending on leaf-litter type (sugar maple (Acer saccharum Marsh.) or white pine (Pinus strobus L.)) or the background population density of conspecifics (0, 25, or 100 m−2). Choice chambers were used to test for selection between habitat conditions. Video recording was used to measure the latency between introduction and establishment. A significantly greater proportion of individuals established burrows in the presence of maple over pine litter, although this preference did not result in a significant difference in latency. For higher population density treatments, the time since establishment of the background population of conspecifics had a significant effect on earthworm habitat selection, with an increasing preference for the high-density habitat over time. Population density had a significant effect on latency, with greater latency under low-density conditions. These results suggest that L. terrestris detects differences in litter type and conspecific population density and modifies its immigration behaviour accordingly. Findings may be useful in predicting and responding to future dispersal patterns of this invader.

Alkaline Dissociation Products of Lumbricus Terrestris Hemoglobin Viewed with the STEM

1981 ◽  
Vol 39 ◽  
pp. 434-435
Author(s):  
O. H. Kapp ◽  
M. Ohtsuki ◽  
N. Robin ◽  
S. N. Vinogradov ◽  
A. V. Crewe
Keyword(s):  
Carbon Film ◽  
Lumbricus Terrestris ◽  
Uranyl Acetate ◽  
Acetate Solution ◽  
Oxygen Carriers ◽  
Complex Molecules ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
Multiple Copies ◽  
Hill Coefficients

Annelid extracellular hemoglobins are among the largest known proteins (M.W = 3.9 x 106), and together with the hemocyanins are the largest known oxygen carriers. They display oxygen affinities generally higher than those o vertebrate hemoglobins with Hill coefficients ranging from slightly higher than unity to values as high as 5-6. These complex molecules are composed of multiple copies of as many as six different polypeptides and posse: approximately 150 hemes per molecule.The samples were diluted to 100-200 μg/ml with distilled water just before application to a thin carbon film (∽15 Å thick). One percent (w/v) uranyl acetate solution was used for negative staining for 2 minutes and dried in air. The specimens were examined with the high resolution STEM. Their general appearance is that of a hexagonal bilayer (Fig. 1), each layer consisting of six spheroidal subunits. The corner to corner hexagonal dimensic is approximately 300 Å and the bilayer thickness approximately 200 Å.

Molecular Views of Ice-Embedded Lumbricus Terrestris Erythrocruorin Obtained By Invariant Classification

1990 ◽  
Vol 48 (1) ◽  
pp. 450-451
Author(s):  
Michael schatz ◽  
Joachim Jäger ◽  
Marin van Heel
Keyword(s):  
Image Interpretation ◽  
Lumbricus Terrestris ◽  
Reference Image ◽  
Large Set ◽  
Multivariate Statistical ◽  
Data Set ◽  
Low Contrast ◽  
Negative Stain ◽  
Reference Images ◽  
Statistical Resolution

Lumbricus terrestris erythrocruorin is a giant oxygen-transporting macromolecule in the blood of the common earth worm (worm "hemoglobin"). In our current study, we use specimens (kindly provided by Drs W.E. Royer and W.A. Hendrickson) embedded in vitreous ice (1) to avoid artefacts encountered with the negative stain preparation technigue used in previous studies (2-4).Although the molecular structure is well preserved in vitreous ice, the low contrast and high noise level in the micrographs represent a serious problem in image interpretation. Moreover, the molecules can exhibit many different orientations relative to the object plane of the microscope in this type of preparation. Existing techniques of analysis requiring alignment of the molecular views relative to one or more reference images often thus yield unsatisfactory results.We use a new method in which first rotation-, translation- and mirror invariant functions (5) are derived from the large set of input images, which functions are subsequently classified automatically using multivariate statistical techniques (6). The different molecular views in the data set can therewith be found unbiasedly (5). Within each class, all images are aligned relative to that member of the class which contributes least to the classes′ internal variance (6). This reference image is thus the most typical member of the class. Finally the aligned images from each class are averaged resulting in molecular views with enhanced statistical resolution.

Convergence of regional population density in Russia over 120 years

2020 ◽  
pp. 133-158
Author(s):  
K. A. Kholodilin ◽  
Y. I. Yanzhimaeva
Keyword(s):  
Population Density ◽  
Spatial Dependence ◽  
Population Distribution ◽  
Regional Level ◽  
Capital City ◽  
County Level ◽  
Spatial Effects ◽  
Russian Regions ◽  
Regional Population ◽  
Regional Population Density

A relative uniformity of population distribution on the territory of the country is of importance from socio-economic and strategic perspectives. It is especially important in the case of Russia with its densely populated West and underpopulated East. This paper considers changes in population density in Russian regions, which occurred between 1897 and 2017. It explores whether there was convergence in population density and what factors influenced it. For this purpose, it uses the data both at county and regional levels, which are brought to common borders for comparability purposes. Further, the models of unconditional and conditional β-convergence are estimated, taking into account the spatial dependence. The paper concludes that the population density equalization took place in 1897-2017 at the county level and in 1926—1970 at the regional level. In addition, the population density increase is shown to be influenced not only by spatial effects, but also by political and geographical factors such as climate, number of GULAG camps, and the distance from the capital city.

Extension of the Spatial PDI Model to Three Dimensions

1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien
Keyword(s):  
Population Density ◽  
Dimensional Space ◽  
Finite Lattice ◽  
Three Dimensional ◽  
Upper Bounds ◽  
Three Dimensions ◽  
Lower And Upper Bounds ◽  
Density Index ◽  
Three Dimensional Space

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.

Community based design approach as initial stage to promote urban composting from a Hill Station of the Philippines

2019 ◽  
Author(s):  
Marcelino Jr Lunag ◽  
Jessie C. Elauria ◽  
Juanito D. Burguillos
Keyword(s):  
Population Density ◽  
Community Involvement ◽  
The Philippines ◽  
Design Stage ◽  
High Population Density ◽  
Community Based ◽  
Hill Station ◽  
Initial Stage ◽  
Household Members ◽  
Community Based Design

This study confirms that lack of space due to high population density restricts household members and the barangay to comply with the existing law regarding composting. With these, community involvement in the design stage of compost bin as initial stage was done accordingly. The participants were voluntarily interviewed and were given questionnaires, which was endorsed and approved by barangay committee.

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