BIOSYNTHESIS OF NEOASPERGILLIC AND NEOHYDROXYASPERGILLIC ACIDS.

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Seasonal and decadal groundwater changes in African sedimentary aquifers estimated using GRACE products and LSMs

Increased groundwater abstraction is important to the economic development of Africa and to achieving many of the Sustainable Development Goals. However, there is little information on long-term or seasonal groundwater trends due to a lack of in situ monitoring. Here we used GRACE data from three products CSR, JPL-MCN and GRGS to examine Terrestrial Water Storage (TWS) changes in 12 African sedimentary aquifers, to examine relationships between TWS and rainfall from TRMM, and estimate Groundwater Storage (GWS) changes using four LSMs CLM2.0, VIC, MOSAIC and NOAH. We find that there are no substantial continuous longterm decreasing trends in groundwater storage from 2002 to 2016in any of the African basins, however, consistent rising groundwater trends amounting to ~1 km3/year and 1.5 km3/year are identified in the Iullemmeden and Senegal basins, respectively and longer term variations in ΔTWS in several basins associated with rainfall patterns. Discrete seasonal ΔTWS responses of ±1‒5 cm/year are indicated by GRACE for each of the basins, with the exception of the Congo, North Kalahari and Senegal basins which display larger seasonal ΔTWS equivalent to approx. ±11‒20 cm/year. The different seasonal responses in ΔTWS provide useful information about groundwater, including the identification of 5 to 9 month accumulation periods of rainfall in many semi-arid and arid basins as well as differences in ΔTWS responses between Sahelian and southern African aquifers to similar rainfall, likely reflecting differences in landcover. Seasonal ΔGWS estimated by combining GRACE ΔTWS with LSM outputs compare inconsistently to available in situ measurements of groundwater recharge from different basins, highlighting the need to further develop the representation of recharge process in LSMs and the need for more in situ observations from piezometry

Quasiparticle Interactions in Fractional Quantum Hall Systems: Justification of Different Hierarchy Schemes

The pseudopotentials describing the interactions of quasiparticles in fractional quantum Hall (FQH) states are studied. Rules for the identification of incompressible quantum fluid ground states are found, based upon the form of the pseudopotentials. States belonging to the Jain sequence nu=n/(1+2pn), where n and p are integers, appear to be the only incompressible states in the thermodynamic limit, although other FQH hierarchy states occur for finite size systems. This explains the success of the composite Fermion picture.Comment: RevTeX, 10 pages, 7 EPS figures, submitted fo Phys.Rev.

Skyrmion Excitations in Quantum Hall Systems

Using finite size calculations on the surface of a sphere we study the topological (skyrmion) excitation in quantum Hall system with spin degree of freedom at filling factors around $\nu=1$. In the absence of Zeeman energy, we find, in systems with one quasi-particle or one quasi-hole, the lowest energy band consists of states with $L=S$, where $L$ and $S$ are the total orbital and spin angular momentum. These different spin states are almost degenerate in the thermodynamic limit and their symmetry-breaking ground state is the state with one skyrmion of infinite size. In the presence of Zeeman energy, the skyrmion size is determined by the interplay of the Zeeman energy and electron-electron interaction and the skyrmion shrinks to a spin texture of finite size. We have calculated the energy gap of the system at infinite wave vector limit as a function of the Zeeman energy and find there are kinks in the energy gap associated with the shrinking of the size of the skyrmion. breaking ground state is the state with one skyrmion of infinite size. In the presence of Zeeman energy, the skyrmion size is determined by the interplay of the Zeeman energy and electron-electronComment: 4 pages, 5 postscript figures available upon reques

The role of superficial geology in controlling groundwater recharge in the weathered crystalline basement of semi-arid Tanzania

Study region Little Kinyasungwe River Catchment, central semi-arid Tanzania. Study focus The structure and hydraulic properties of superficial geology can play a crucial role in controlling groundwater recharge in drylands. However, the pathways by which groundwater recharge occurs and their sensitivity to environmental change remain poorly resolved. Geophysical surveys using Electrical Resistivity Tomography (ERT) were conducted in the study region and used to delineate shallow subsurface stratigraphy in conjunction with borehole logs. Based on these results, a series of local-scale conceptual hydrogeological models was produced and collated to generate a 3D conceptual model of groundwater recharge to the wellfield. New hydrological insights for the region We propose that configurations of superficial geology control groundwater recharge in dryland settings as follows: 1) superficial sand deposits act as collectors and stores that slowly feed recharge into zones of active faulting; 2) these fault zones provide permeable pathways enabling greater recharge to occur; 3) ‘windows’ within layers of smectitic clay that underlie ephemeral streams may provide pathways for focused recharge via transmission losses; and 4) overbank flooding during high intensity precipitation events increases the probability of activating such permeable pathways. These conceptual models provide a physical basis to improve numerical models of groundwater recharge in drylands, and a conceptual framework to evaluate strategies (e.g., Managed Aquifer Recharge) to artificially enhance the availability of groundwater resources in these regions

Characteristics of high-intensity groundwater abstractions from weathered crystalline bedrock aquifers in East Africa

Weathered crystalline bedrock aquifers sustain water supplies across the tropics, including East Africa. Although well yields are commonly <1 L s−1, more intensive abstraction occurs and provides vital urban and agricultural water supplies. The hydrogeological conditions that sustain such high abstraction from crystalline bedrock aquifers remain, however, poorly characterised. Five sites of intensive groundwater abstraction (multiple boreholes yielding several L s−1 or more) were investigated in Uganda and Tanzania. Analysis of aquifer properties data indicates that the sites have transmissivities of 10–1,000 m2 day−1, which is higher than generally observed in deeply weathered crystalline bedrock aquifers. At four of the five sites, weathered bedrock (saprolite) is overlain by younger superficial sediments, which provide additional storage and raise the water table within the underlying aquifer. Residence-time indicators suggest that: (1) abstracted water derives, in part, from modern recharge (within the last 10–60 years); and (2) intensive abstraction is sustained by recharge occurring over several decades. This range of encountered residence times indicates a degree of resilience to contemporary climate variability (e.g. short-term droughts), although the long-term sustainability of intensive abstractions remains uncertain. Evidence from one site in Tanzania (Makutapora) highlights the value of multi-decadal groundwater-level records in establishing the long-term viability of intensive groundwater abstraction, and demonstrates the influence of intra-decadal climate variability in determining the magnitude and frequency of recharge

Еволюція рослинного світу в природному і культигенному середовищі

У ході засідань Міжнародної наукової конференції “Еволюція рослинного світу в природному і культигенному середовищі”, присвяченої 200-річчю від Дня народження Чарльза Дарвіна, обговорено актуальні питання еволюційної теорії, ботаніки, фізіології рослин, інтродукції, генетики й селекції, екології, збереження і примноження глобального та локального біорізноманіття, лісових культур і фітомеліорації та інших біологічних наук.В ходе заседаний Международной научной конференции “Эволюция растительного мира в естественной и культигенной среде”, посвященной 200-летию со дня рождения Чарльза Дарвина, обсуждены актуальные вопросы эволюционной теории, ботаники, физиологии растений, интродукции, генетики и селекции, экологии, сохранения и приумножения глобального и локального биоразнообразия, лесных культур и фитомелиорации и других биологических наук.During meetings of the International scientific conference “Evolution of the natural and cultivated plants” to devoted a 200-year from the day of birth of Charles Darwin topical problems of the evolutional theory are discussed, including botany, physiology of plants, introduction of plants, genetics and breeding of plants, ecology, preventing the loss of global and loca biodiversity, arboriculture, forest-growing and other biological sciences

Groundwater in the Indo-Gangetic basin: evolution of groundwater typologies

The Indo-Gangetic Basin comprises one of the world’s most important aquifers. The basin is home to approximately 1 billion people and encompasses northern and eastern India, much of Bangladesh, parts of southern Nepal and the most populous areas of Pakistan. Despite the presence of large rivers, much of the basin’s population are dependent on groundwater for drinking water, and the groundwater resource is highly exploited through an estimated 20 million boreholes to support a globally important agricultural industry. The security of supply from this aquifer is threatened by environmental change and increased abstraction. In order to help understand the aquifer and characterise its resilience to change we have developed a groundwater typology map for the basin