996 resultados para Great Artesian Basin
Resumo:
Following an unprecedented boom, since 2008 Ireland has experienced a severe economic crisis. Considerable debate persists as to where the heaviest burden of the recession has fallen. Conventional measures of income poverty and inequality have a limited capacity to answer this question. Our analysis, which focuses on economic stress and the mediating role of material deprivation, provides no evidence for individualization or class polarization. Instead we find that while economic stress level are highly stratified in income class and social class terms in both boom and bust periods, the changing impact of class is contingent on life course stage. The affluent income class remained largely insulated from the experience of economic stress. However, it saw its relative advantage overthe income poor class decline at the earlier stage of the life-course. At the other end of the hierarchy, the income poor experienced a relative improvement in their situation in the early life course phases. The precarious income class experienced some improvement in its situation at the earlier life course stages while the outcomes for the middle classes remain unchanged. In the mid-life course stages the precarious and lower middle classes experienced disproportionate increase in their stress levels while at the later life-cycle stage it is the combined middle classes that lost out. Additional effects over time relating to social class are restricted to the deteriorating situation of the petit bourgeoisie at the middle stage of the life-course. The pattern is clearly a good deal more complex that suggested by conventional notions of ‘middle class squeeze’ and points to the distinctive challenges relating to welfare and taxation policy faced by governments in the Great Recession.
Resumo:
Lower Cretaceous meandering and braided fluvial sandstones of the Nubian Formation form some of the most important subsurface reservoir rocks in the Sirt Basin, north-central Libya. Mineralogical, petrographical and geochemical analyses of sandstone samples from well BB6-59, Sarir oilfield, indicate that the meandering fluvial sandstones are fine- to very fine-grained subarkosic arenites (av. Q91F5L4), and that braided fluvial sandstones are medium- to very coarse-grained quartz arenites (av. Q96F3L1). The reservoir qualities of these sandstones were modified during both eodiagenesis (ca. <70oC; <2 km) and mesodiagenesis (ca. >70oC; >2km). Reservoir quality evolution was controlled primarily by the dissolution and kaolinitization of feldspars, micas and mud intraclasts during eodiagenesis, and by the amount and thicknessof grain-coating clays, chemical compaction and quartz overgrowths during mesodiagenesis. However, dissolution and kaolinitization of feldspars, micas and mud intraclasts resulted in the creation of intercrystalline micro- and mouldic macro-porosity and permeability during eodiagenesis, which were more widespread in braided fluvial than in meandering fluvial sandstones. This was because of the greater depositional porosity and permeability in the braided fluvial sandstones which enhanced percolation of meteoric waters. The development of only limited quartz overgrowths in the braided fluvial sandstones, in which quartz grains are coated by thick illite layers, retained high porosity and permeability (12-23 % and 30- 600 mD). By contrast, meandering fluvial sandstones underwent porosity loss as a result of quartz overgrowth development on quartz grains which lack or have thin and incomplete grain-coating illite (2-15 % and 0-0.1mD). Further loss of porosity in the meandering fluvial sandstones occurred as a result of chemical compaction (pressuredissolution) induced by the occurrence of micas along grains contacts. Otherdiagenetic alterations, such as the growth of pyrite, siderite, dolomite/ankerite and albitization, had little impact on reservoir quality. The albitization of feldspars may have had minor positive influence on reservoir quality throughthe creation of intercrystalline micro-porosity between albite crystals.The results of this study show that diagenetic modifications of the braided and meandering fluvial sandstones in the Nubian Formation, and resulting changes in reservoir quality, are closely linked to depositional porosity and permeability. They are also linked to the thickness of grain-coating infiltrated clays, and to variations in detrital composition, particularly the amounts of mud intraclasts, feldspars and mica grains as well as climatic conditions.
Resumo:
In this paper we make use of the first and second waves of the 2008 and 1998 cohorts of the Growing Up in Ireland study, to develop a multidimensional and dynamic approach to understanding the impact on families and children in Ireland of the Great Recession. Economic vulnerability is operationalised as involving a distinctive risk profile in relation to relative income, household joblessness and economic stress. We find that the recession was associated with a significant increase in levels of economic vulnerability and changing risk profiles involving a more prominent role for economic stress for both the 2008 and 1998 cohorts. The factors affecting vulnerability outcomes were broadly similar for both cohorts. Persistent economic vulnerability was significantly associated with lone parenthood, particularly for those with more than one child, lower levels of Primary Care Giver (PCG) education and to a lesser extent younger age of PCG at child’s birth, number of children and a parent leaving or dying. Similar factors were associated with transient vulnerability in the first wave but the magnitude of the effects was significantly weaker particularly in relation to lone parenthood and level of education of the PCG. For entry into vulnerability the impact of these factors was again substantially weaker than for persistent and transient vulnerability indicating a significantly greater degree of socio-economic heterogeneity among the group that became vulnerable during the recession. The findings raise policy and political problems that go beyond those associated with catering for groups that have tended to be characterized by high dependence on social welfare.
Resumo:
Recent research in Europe, Africa, and Southeast Asia suggests that we can no longer assume a direct and exclusive link between anatomically modern humans and behavioral modernity (the 'human revolution'), and assume that the presence of either one implies the presence of the other: discussions of the emergence of cultural complexity have to proceed with greater scrutiny of the evidence on a site-by-site basis to establish secure associations between the archaeology present there and the hominins who created it. This paper presents one such case study: Niah Cave in Sarawak on the island of Borneo, famous for the discovery in 1958 in the West Mouth of the Great Cave of a modern human skull, the 'Deep Skull,' controversially associated with radiocarbon dates of ca. 40,000 years before the present. A new chronostratigraphy has been developed through a re-investigation of the lithostratigraphy left by the earlier excavations, AMS-dating using three different comparative pre-treatments including ABOX of charcoal, and U-series using the Diffusion-Absorption model applied to fragments of bones from the Deep Skull itself. Stratigraphic reasons for earlier uncertainties about the antiquity of the skull are examined, and it is shown not to be an `intrusive' artifact. It was probably excavated from fluvial-pond-desiccation deposits that accumulated episodically in a shallow basin immediately behind the cave entrance lip, in a climate that ranged from times of comparative aridity with complete desiccation, to episodes of greater surface wetness, changes attributed to regional climatic fluctuations. Vegetation outside the cave varied significantly over time, including wet lowland forest, montane forest, savannah, and grassland. The new dates and the lithostratigraphy relate the Deep Skull to evidence of episodes of human activity that range in date from ca. 46,000 to ca. 34,000 years ago. Initial investigations of sediment scorching, pollen, palynomorphs, phytoliths, plant macrofossils, and starch grains recovered from existing exposures, and of vertebrates from the current and the earlier excavations, suggest that human foraging during these times was marked by habitat-tailored hunting technologies, the collection and processing of toxic plants for consumption, and, perhaps, the use of fire at some forest-edges. The Niah evidence demonstrates the sophisticated nature of the subsistence behavior developed by modern humans to exploit the tropical environments that they encountered in Southeast Asia, including rainforest. (c) 2006 Elsevier Ltd. All rights reserved.
Resumo:
1. The prediction and mapping of climate in areas between climate stations is of increasing importance in ecology.
2. Four categories of model, simple interpolation, thin plate splines, multiple linear regression and mixed spline-regression, were tested for their ability to predict the spatial distribution of temperature on the British mainland. The models were tested by external cross-verification.
3. The British distribution of mean daily temperature was predicted with the greatest accuracy by using a mixed model: a thin plate spline fitted to the surface of the country, after correction of the data by a selection from 16 independent topographical variables (such as altitude, distance from the sea, slope and topographic roughness), chosen by multiple regression from a digital terrain model (DTM) of the country.
4. The next most accurate method was a pure multiple regression model using the DTM. Both regression and thin plate spline models based on a few variables (latitude, longitude and altitude) only were comparatively unsatisfactory, but some rather simple methods of surface interpolation (such as bilinear interpolation after correction to sea level) gave moderately satisfactory results. Differences between the methods seemed to be dependent largely on their ability to model the effect of the sea on land temperatures.
5. Prediction of temperature by the best methods was greater than 95% accurate in all months of the year, as shown by the correlation between the predicted and actual values. The predicted temperatures were calculated at real altitudes, not subject to sea-level correction.
6. A minimum of just over 30 temperature recording stations would generate a satisfactory surface, provided the stations were well spaced.
7. Maps of mean daily temperature, using the best overall methods are provided; further important variables, such as continentality and length of growing season, were also mapped. Many of these are believed to be the first detailed representations at real altitude.
8. The interpolated monthly temperature surfaces are available on disk.
Resumo:
Extensive drilling of the Great Barrier Reef (GBR) in the 70s and 80s illuminated the main factors controlling reef growth during the Holocene. However, questions remain about: (1) the precise nature and timing of reef "turnon" or initiation, (2) whether consistent spatio-temporal patterns occur in the bio-sedimentologic response of the reef to Holocene sea-level rise then stability, and (3) how these factors are expressed in the context of the different evolutionary states (juvenile-mature-senile reefs). Combining 21 new C14-AMS and 146 existing recalibrated radiocarbon and U/Th ages, we investigated the detailed spatial and temporal variations in sedimentary facies and coralgal assemblages in fifteen cores across four reefs (Wreck, Fairfax, One Tree and Fitzroy) from the Southern GBR. Our newly defined facies and assemblages record distinct chronostratigraphic patterns in the cores, displaying both lateral zonation across the different reefs and shallowing upwards sequences, characterised by a transition from deep (Porites/faviids) to shallow (Acropora/Isopora) coral types. The revised reef accretion curves show a significant lag period, ranging from 0.7-2 ka, between flooding of the antecedent Pleistocene substrate and Holocene reef turn-on. This lag period and dominance of more environmentally tolerant early colonizers (e.g., domal Porites and faviids), suggests initial conditions that were unfavourable for coral growth. We contend that higher input of fine siliciclastic material from regional terrigenous sources, exposure to hydrodynamic forces and colonisation in deeper waters are the main factors influencing initially reduced growth and development. All four reefs record a time lag and we argue that the size and shape of the antecedent platform is most important in determining the duration between flooding and recolonisation of the Holocene reef. Finally, our study of Capricorn Bunker Group Holocene reefs suggests that the size and shape of the antecedent substrate has a greater impact on reef evolution and final evolutionary state (mature vs. senile), than substrate depth alone.
Resumo:
Biogeochemical relationships and the level of arsenic (As) contamination of groundwater and surface sediments in the Haor Basin of Bangladesh were assessed to see if surface sediments gave any indication of underlying As cycling. The Haor areas under study have been found to be affected with high As (up to 331 μg/L) in groundwater, with contamination of both shallow and deep aquifers. Highly significant relationships of As with Dissolved Organic Carbon (DOC) in groundwater and Total Carbon (TC) and Organic Carbon (OC) in sediments are indicative of reductive dissolution of iron (Fe) and/or manganese (Mn) oxides/oxyhydroxides coupled with biodegradation of organic matter as the dominant processes to release As in groundwater. This study also reveals that As geochemistry in the surface sediments has limited influence on As geochemistry in the groundwater of the Haor Basins. © 2012 Taylor & Francis Group.
Resumo:
Diploid (2n = 2x = 20) and triploid (2n = 3x = 30) Fasciola hepatica have been reported in the UK, and in Asia diploid, triploid and mixoploid (2x/3x) Fasciola spp. exist but there is little information to indicate how common triploidy is, particularly in UK fluke. Here the ploidy of 565 adult F. hepatica from 66 naturally infected British sheep and 150 adult F. hepatica from 35 naturally infected British cattle was determined. All 715 of these parasites were diploid, based on observation of 10 bivalent chromosomes and sperm (n = 335) or, since triploids are aspermic, sperm alone (n = 380). This constitutes the first extensive analysis of the ploidy of F. hepatica field isolates from Great Britain and shows that most F. hepatica isolated from cattle and sheep are diploid and have the capacity to sexually reproduce. These data suggest that triploidy, and by extension parthenogenesis, is rare or non-existent in wild British F. hepatica populations. Given that F. hepatica is the only species of Fasciola present in Britain our results indicate that the parasite is predominantly diploid in areas where F. hepatica exists in isolation and suggests that triploidy may only originate in natural populations where co-infection of F. hepatica and its sister species Fasciola gigantica commonly occurs.