present day Research Papers - Academia.edu (original) (raw)

Zeekoevlei is the largest freshwater lake in South Africa and has a century-long history of anthropogenic impact that caused hyper-eutrophic conditions. We used biomarkers (alkanes and pigments), stable isotopes (d13C and d15N), rates... more

Zeekoevlei is the largest freshwater lake in
South Africa and has a century-long history of
anthropogenic impact that caused hyper-eutrophic
conditions. We used biomarkers (alkanes and pigments),
stable isotopes (d13C and d15N), rates of
primary palaeoproduction and total inorganic carbon
(TIC) accumulation rates in the lake sediments to
investigate changes in plankton and macrophyte
communities in response to anthropogenic activities
in this shallow lake. Specific alkanes and pigment
(chlorophyll a, b,b-carotene, echinenone, fucoxanthin
and zeaxanthin) concentrations in lake waters indicated
the present-day hyper-eutrophic condition and
seasonal fluctuations of cyanobacteria, zooplankton
and diatom populations. Eutrophic conditions were
initiated in the lake with the start of recreational
activities and construction of a sewage treatment plant
in the early 1920s. The lake transformed from a
eutrophic to a hyper-eutrophic waterbody following
damming, pondweed eradication and accelerated
catchment-derived nutrient input. The change in lake
trophic state was recorded by a sharp decline in the
terrestrial to aquatic ratio (TAR) of specific n-alkanes,
low carbon preference index (CPI) and increased d13C
values in the sediment core. In addition, the aquatic
macrophyte n-alkane proxy (Paq) values (1) indicated
a slow takeover by floating macrophytes after
the eradication of submerged pondweeds in 1951.
Elevated n-alkane, total alkane and pigment
(chlorophyll a, b,b-carotene, zeaxanthin and
zeaxanthin to b,b-carotene ratio) concentrations, low
d15N values and low TIC accumulation rates in the
upper middle section of the core indicated the
beginning of intense cyanobacterial blooms after the
dredging in 1983. Although the cyanobacterial population
has decreased in recent years, hyper-eutrophic
conditions are reflected by low CPI<0.04 and TAR<1
values at the top of the sediment core.

... From the Sankranta of Sawan (July–August) to that of Bhadon (August–September), weeding is carried out. ... resistance in general Kullakar, Kappa samba, Kala samba, Neelam samba, Perungar, Adt 1 (Tamil Nadu), Ptb 9, Ptb 7, Ptb 10, Ptb... more

... From the Sankranta of Sawan (July–August) to that of Bhadon (August–September), weeding is carried out. ... resistance in general Kullakar, Kappa samba, Kala samba, Neelam samba, Perungar, Adt 1 (Tamil Nadu), Ptb 9, Ptb 7, Ptb 10, Ptb 20, Asha (Kerala), Bhutmuri, Bhogjira ...

The extent and the spatial patterns of landscape transformation we observe today are the result of the historic human settlement process, often dating back hundreds or thousands of years. Analyzing and reconstructing those historical... more

The extent and the spatial patterns of landscape transformation we observe today are the result of the historic human settlement process, often dating back hundreds or thousands of years. Analyzing and reconstructing those historical patterns helps to advance the understanding of the dynamics and persistence of present-day ecosystems. This article explores this reconstruction by identifying and analyzing historic drivers of landscape change for seven periods between 1500 and 2000, and presents historical land use maps ...

Willems-Braun social objects (Frankenberg and Mani 1993). &amp;amp;amp;amp;#x27;Postcoloniality,&amp;amp;amp;amp;#x27; after all, appears quite different when applied to different social groups within now-independent white settler... more

Willems-Braun social objects (Frankenberg and Mani 1993). &amp;amp;amp;amp;#x27;Postcoloniality,&amp;amp;amp;amp;#x27; after all, appears quite different when applied to different social groups within now-independent white settler colonies like the US, to the mestizaje of Latin America or to indigenous peoples in Canada or ...

P of which 62,046km P2 P are land and 2,543km P2 P inland-water. The length of the State boundary is 1,900km, of which 1,400km is on land, including 343km with Estonia in the north, 282km with the Russian Federation in the east, 167km... more

P of which 62,046km P2 P are land and 2,543km P2 P inland-water. The length of the State boundary is 1,900km, of which 1,400km is on land, including 343km with Estonia in the north, 282km with the Russian Federation in the east, 167km with Belarus in the southeast and 567km with Lithuania in the south. The length of the coastline is 494km. Latvia is located on the NW edge of the East European Plain that is characterized by slight variations in elevation. Relief of Latvia is characterized by low hypsography (0-312m above sea level - a.s.l.). About 44% of Latvia is at or below 80m a.s.l., 76% up to 120m and 24% above 120m a.s.l. Only 1.6% of the territory is located above 200m a.s.l. The average elevation is 87m a.s.l. The highest point is Gaizinkalns (312 a.s.l). The present day topography was mainly formed as a result of the Pleistocene glaciation, particularly the last Baltic (Weichselian) event. Despite the low hypsography, some parts of the uplands have remarkable relief.

In this paper we give a pedagogical review of the recent observational results in cosmology from the study of type Ia supernovae and anisotropies in the cosmic microwave background. By providing consistent constrainst on the cosmological... more

In this paper we give a pedagogical review of the recent observational results in cosmology from the study of type Ia supernovae and anisotropies in the cosmic microwave background. By providing consistent constrainst on the cosmological parameters, these results paint a concrete picture of our present-day universe. We present this new picture and show how it can be used to answer some of the basic questions that cosmologists have been asking for several decades. This paper is most appropriate for students of general relativity and/or relativistic cosmology.