scholarly journals Erosive features caused by a Magellanic penguin (Spheniscus magellanicus) colony on Martillo Island, Beagle Channel, Argentina

2020 ◽  
Vol 46 (2) ◽  
pp. 477-496
Author(s):  
D.R.A. Quiroga ◽  
A. Coronato ◽  
G. Scioscia ◽  
A. Raya-Rey ◽  
A. Schiavini ◽  
...  
Keyword(s):  
Austral Summer ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Magellanic Penguin ◽  
Forest Patches ◽  
Spheniscus Magellanicus ◽  
Beagle Channel ◽  
Soils And Sediments ◽  
Degradation Analysis ◽  
Penguin Colony

An active Magellanic penguin (Spheniscus magellanicus) colony has been established on Martillo Island, Beagle Channel (54°54´26” S; 67°22´58” W) since 1976. It is located in remnants of eroded drumlins placed in both ending and joined by gravel terraces of glaciofluvial and marine origin. Forest patches occupy the eastern side of the island while most of the island is covered by bushes, tussocks and grasses. This paper presents penguins as bio-erosion agents on glacial and marine landforms. An analysis of multiple criteria surveyed in the field was performed, using Quantum GIS® 3.2.1 with remote sensing images and a digital model terrain of 12 m resolution. The morphometric data and multicriterial evaluation were collected during 2016-2017 austral summer. Soils and sediments of each landform (drumlin, glaciofluvial terrace, raised beach and beach) were sampled for particle size analysis, to determine if there is any relationship between the morphometric parameters of the cave and the sediments. Four bio-erosion classes were defined based on the erosion features observed in the field. “Moderate” was the prevailing erosion class recorded, in the E-NE part of the island. Bio-erosion features are mainly developed on the N facing slope of the east of the island, where a natural gully drains rainfall water, and over the glaciofluvial and marine terrace surfaces. Erosive features such as caves and bridges are mainly developed in silty drumlins. Pedestals are developed on bare soils and tussocks. Trails and cracks were also described as bio-erosion. No erosive features were recorded in the W part of the island. The bio-erosion map is one of the inputs for environmental degradation analysis and population dynamic research which is being done in the Magellanic penguin colony on Martillo Island, Beagle Channel.

Size characteristics of soils and sediments with special reference to clay fractions

Soil Research ◽  
1979 ◽  
Vol 17 (3) ◽  
pp. 383 ◽  
Author(s):  
PH Walker ◽  
J Hutka
Keyword(s):  
Particle Size ◽  
Size Fraction ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Size Fractions ◽  
Soils And Sediments ◽  
Eastern Australia ◽  
Fine Clay ◽  
Lake Floor ◽  
Log Normal

Soils and sediments from south-eastern Australia were examined to determine whether texture B horizons had distinctive and unique particle-size characteristics. Most texture B horizons had higher contents of fine clay (<0.2 �m) than coarse clay (0.2-2 �m), whereas coarse clay was the dominant clay-size fraction in A and C horizons. Sequences of soils in alluvium showed a systematic increase in particle-size differentiation with increasing stratigraphic age and corresponding increases in the proportion of fine clay in their B horizons. Pedologically unmodified, clay-rich sediments generally had lower contents of fine clay and higher contents of silt than B horizons. However, sediments of a lake floor and samples of argillans had clay-size fractions similar to B horizons. The distribution of fine clay in soils, determined here by centrifugal sedimentation, was poorly related to illuviated clay determined microscopically. Detailed particle-size data showed that texture B horizons were more enriched than adjacent horizons by a fraction with upper size limits between 0.25 and 0.5 �m. The greater the profile texture contrast, the more pronounced this enrichment became. The enriched clay-size fractions of these B horizons had the particle-size characteristics of log normal distributions. Within the clay-size range of texture B horizons, the fraction < 0.5 �m was the most directly related to surface area measurements made on dry soil samples. Sediments of a lake floor and samples of argillans had similar clay-size characteristics to soil B horizons. It was concluded that particle-size differentiation in these soils was related mainly to pedogenetic processes within the profile. However, the particle-size characteristics of texture B horizons are not unique. Criteria other than those based on particle-size analysis are therefore required to determine the relative importance of translocation and weathering.

Intra- and interannual variation in the diet of the Magellanic penguin (Spheniscus magellanicus) at Martillo Island, Beagle Channel

Polar Biology ◽  
2014 ◽  
Vol 37 (10) ◽  
pp. 1421-1433 ◽  
Author(s):  
Gabriela Scioscia ◽  
Andrea Raya Rey ◽  
Ricardo A. Saenz Samaniego ◽  
Olga Florentín ◽  
Adrián Schiavini
Keyword(s):  
Interannual Variation ◽  
Magellanic Penguin ◽  
Spheniscus Magellanicus ◽  
Beagle Channel

Particularities of overdetermined linear systems arising in particle size analysis

1992 ◽  
Vol 2 (8) ◽  
pp. 1547-1555
Author(s):  
D. M. Calistru ◽  
R. Mondescu ◽  
I. Baltog
Keyword(s):  
Particle Size ◽  
Linear Systems ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Overdetermined Linear Systems

Acyclovir Loaded Solid Lipid Nanoparticle Based Cream: A Novel Drug Delivery System

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
EL- Assal I. A. ◽  
Retnowati .
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Antiviral Agent ◽  
Study Drug ◽  
Particle Size Analysis ◽  
Stability Study ◽  
Size Analysis ◽  
Solid Lipid ◽  
Dermal Delivery

Objective of the present investigation was enthused by the possibility to develop solid lipid nanoparticles (SLNs) of hydrophilic drug acyclovir. Also study vitro and vivo drug delivery. Methods: Drug loaded SLNs (ACV-SLNs) were prepared by high pressure homogenization of aqueous surfactant solutions containing the drug-loaded lipids in the melted or in the solid state with formula optimization study (Different lipid concentration, drug loaded, homogenization / stirring speed and compritol 888ATO: drug ratio). ACV - SLN incorporated in cream base. The pH was evaluated and rheological study. Drug release was evaluated and compared with simple cream- drug, ACV – SLN with compritol 888ATO and marketed cream. The potential of SLN as the carrier for dermal delivery was studied. Results: Particle size analysis of SLNs prove small, smooth, spherical shape particle ranged from 150 to 200 nm for unloaded and from 330 to 444 nm for ACV loaded particles. The EE% for optimal formula is 72% with suitable pH for skin application. Rheological behavior is shear thinning and thixotropic. Release study proved controlled drug release for SLNs especially in formula containing compritol88 ATO. Stability study emphasized an insignificant change in SLNs properties over 6 month. In-vivo study showed significantly higher accumulation of ACV in stratum corneum, dermal layer, and receptor compartment compared with blank skin. Conclusion: AVC-loaded SLNs might be beneficial in controlling drug release, stable and improving dermal delivery of antiviral agent(s).

APSAS; an Automated Particle Size Analysis System

Circular ◽  
1985 ◽  
Author(s):  
Lawrence J. Poppe ◽  
A.H. Eliason ◽  
J.J. Fredericks
Keyword(s):  
Particle Size ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Analysis System

Preparation of reference materials for particle-size analysis of silts and clays

1979 ◽  
Author(s):  
Bruce M. Delaney ◽  
L.J. Schroder
Keyword(s):  
Particle Size ◽  
Reference Materials ◽  
Particle Size Analysis ◽  
Size Analysis
Sign in / Sign up

Export Citation Format

Share Document