We monitored the chemical and isotopic compositions of wet depositions, at the Pyramid International Laboratory (5050 ma.s.l.), and surrounding surface waters, in the Khumbu basin, to understand precipitation chemistry and to obtain insights regarding ecosystem responses to atmospheric inputs. The major cations in the precipitation were NH4(+) and Ca(2+), whereas the main anion was HCO3(-), whi...

A 56-year time series of human plague cases (Yersinia pestis) in the western United States was used to explore the effects of climatic patterns on plague levels. We found that the Pacific Decadal Oscillation (PDO), together with previous plague levels and above-normal temperatures, explained much of the plague variability. We propose that the PDO's impact on plague is conveyed via its effect on...

Here, I describe the geographical distribution of the savanna types in Namibia and identify the factors controlling the occurrence of each savanna type in relation to the amount of annual precipitation and the various physiographical regions, including the mopane ( Colophospermum mopane) area. The different types of savanna can be distinguished on the basis of the leaf habits of the dominant ve...

Acemannan from Aloe barbadensis was obtained with four processes: 1) size exclusion chromatography (SEC) using Sepharose CL-4B matrix followed by ethanolic precipitation; 2) SEC, ultrafiltration using hollow-fiber cartridges (30 kDa or 0.1 μm) and ethanolic precipitation; 3) SEC, precipitation with cetyltrimethylammonium bromide (CTAB) and ethanolic precipitation; and 4) direct precipitation wi...

BACKGROUND In geochemically perturbed systems where porewater and mineral assemblages are unequilibrated the processes of mineral precipitation and dissolution may change important transport properties such as porosity and pore diffusion coefficients. These reactions might alter the sealing capabilities of the rock by complete pore-scale precipitation (cementation) of the system or by opening n...

Vegetation phenology in temperate grasslands is highly sensitive to climate change. However, it is still unclear how the timing of vegetation phenology events (especially for autumn phenology) is altered in response to climate change across different grassland types. In this study, we investigated variations of the growing season start (SOS) and end (EOS), derived from Moderate Resolution Imagi...

Analyses of sediment cores from Marcella Lake, a small, hydrologically closed lake in the semi-arid southwest Yukon, provides effective moisture information for the last 4500 years at century-scale resolution. Water chemistry and oxygen isotope analyses from lakes and precipitation in the region indicate that Marcella Lake is currently enriched in O by summer evaporation. Past lake water values...

This thesis had three different objectives: i) to discover different methods for kraft lignin purification that could be used alongside acid precipitation, ii) test the most suitable treatment on laboratory scale and evaluate the potentiality of this method as a kraft lignin purification method, and iii) to compare the feasibility of lignin purification alongside the acid precipitation compared...

Drought is a complex phenomenon which can be characterised mainly by its severity, duration and areal extent. Among these three dimensions, drought severity is the key factor which can be used for drought analysis. Drought indices are typically used to assess drought severity in a meaningful way. DrinC (Drought Indices Calculator) is a software package which was developed for providing a simple...