bluuebunny/crossref_metadata_2025_split huggingface dataset:
The inter‐relationship between magnification, field of view and contrast reserve: the effect on reading performance
Authors: Mohammed Zainora , Dickinson Christine M. 
Published: December 2007

SummaryFor the reading task, contrast reserve is defined as the ratio of the letter contrast of the printed letters, to the reader's contrast threshold. Acuity reserve is the ratio of the print size used for the reading task, to the reader's visual acuity. The effects of low contrast reserve on reading performance were investigated at various magnifications, ranging from 3 × to 7.5 ×, with the field of view systematically controlled. Eye movements were recorded whilst normally sighted subjects read using the magnifiers. It was shown that with adequate contrast reserve, increasing the field of view improved the reading rate because of the resulting increase in forward saccade length. Conversely, reducing the contrast reserve slowed the reading rate by decreasing the length of forward saccades and increasing the mean fixation duration, suggesting that the perceptual span is reduced at low contrast reserve. This study also shows that when the contrast reserve is low, providing magnification higher than that required for letter recognition (that is, increasing the acuity reserve) will not improve the reading performance. Furthermore, even when the contrast reserve was high, reading rates were lower for the magnifications of 5 × and higher, because increases in saccade length do not match those of the retinal image size at these magnifications.
Why Some Adult Canadians Do Not Have Blood Pressure Measured
Authors: Amankwah Ernest , Campbell Norman R. C. , Maxwell Colleen , Onysko Jay , Quan Hude 
Published: December 2007

Regular blood pressure (BP) measurements are required to identify people with hypertension and to optimally manage their cardiovascular risk. Analyses of data from the 2000–2001 Canadian Community Health Survey showed that most adult Canadians have had a BP assessment in the previous 2 years and few have never had one. Large numbers of persons without BP recordings were observed, however, among persons who were younger, were male, who did not have either a regular doctor or physician contact in the previous year, who were recent immigrants or visible minorities (nonwhite and non‐Aboriginal), and who spoke neither French nor English. Common reasons reported for not having a BP assessment included believing it was not necessary and simply not getting around to it. Education programs targeting those at risk as well as more convenient BP screening may improve awareness and testing. (J Clin Hypertens. 2007;9:944–951)
COOL SHALLOW ORIGIN OF PETROLEUM—MICROBIAL GENESIS AND SUBSEQUENT DEGRADATION
Authors: Yi‐gang Zhang 
Published: December 2007

The thermodynamic equilibria of petroleum hydrocarbons and the geographic and depth distributions of oil occurrences suggest that petroleum is formed at shallow depths and low temperatures. The currently prevailing theory of origin from kerogen is inconsistent with known data, especially in relation to the non‐marine oils of China.As an alternative, a hypothesis of origin by microbial diagenesis is proposed. Microbial activities are ubiquitous at depths of less than 2,800 m. Sedimentary organic matter is first transformed into microbial lipids which migrate, accumulate and are finally converted into petroleum at 50‐8Od̀C. The energy enrichment process is performed first by microbial activities and then by heat. This process is irreversible in strictly anaerobic conditions because anaerobes cannot utilize hydrocarbons.The dependence of the efficiency of primary migration upon the pore geometry of source rocks and upon the dimensions of microbial remains deserves emphasis.The diagenesis of carbonate sediments is characterised by the “openness” of the systems, and by the facility with which local dissolution and reprecipitation occur. If the deposition of a carbonate sediment is sufficiently rapid, and is followed by a quickly‐consolidated cover so as to prevent the supply of molecular oxygen for microbes, much pore space and hence pore water may be retained within the sediment, so that it becomes a possible source bed. The carbon and oxygen isotope compositions of carbonate minerals can be used as indicators to define both carbonate and clastic source beds.Volcanic hydrogen gas ascending into a sedimentary basin may increase the petroleum potential of the basin by supporting the growth of anaerobes which produce source material.
MOZAMBIQUE: A NEW GEOLOGICAL FRAMEWORK FOR HYDROCARBONS EXPLORATION
Authors: Coster P. W. , Lawrence S. R. , Fortes G. 
Published: December 2007

Modern exploration for hydrocarbons began in Mozambique in 1981. The newly‐acquired data augment those gathered in the territory prior to plitical independence in 1975, and provide a basis for an updated appraisal of the country's hydrocarbon potential. This is concentrated in the marginal Mozambique and Rovuma Basins, whose development was initiated during the break‐up of Gondwana. a “fit” for Madagascar against coastal Tanzania and Somailia is accepted as representing the region's early plate‐tectonic configuration.Both basins display a polyphase history. Initial Karroo rifting was followed by tow distinct phases of continental separation, one beginning in the mid‐jurassic and the other in the mid‐Cretaceous. They were differentiated by orthogonal exes of regional stress. Margins which had developed in a passive margin extensional regime in the early phase were subjected to shearing stresses in the late phase, and vice versa. Renewed attempts at break‐up in the Late Cretaceous and Early Tertiary, which led to the development of the East African Rift System, have left a structural overprint.This basic three‐phase model allows an understanding of basin development and a rationalisation of structural and stratigraphic evolution. The “break‐up” unconformity is dated at approximately 165 MM ybp † with subsidence thereafter related to distinct phases of plate divergence‐ “proto‐ocenic”, and “constrained” and “free” dreft. Marginal marine Middle and Upper Jurassic and marine lower Cretaceous sediments are overlain by a progradational Upper cretaceous and tertiary section.An understanding of structural and stratigraphic development has been combined with the critical aspects of petroleum geology to predict hydrocarbon plays in the two coastal basins. Known hydrocarbon occurrences, such as the gas discovery at Pande, and the gas and condensate discovery at Temane, are fitted into this scheme, and fairways identified for future exploration. These include, inter alia, Cretaceous submarine fan and chenier sand developments in the Mozambique Basin, and structural and statigraphic Jurassic plays in the Rovuma.
RELATIVE MOTIONS IN GEOLOGY: SOME PHILOSOPHICAL DIFFERENCES
Authors: Pratsch J.‐C. 
Published: December 2007

The motion of geological bodies is always relative. Regardless of the dimensions of a sample, our interpretation and understanding of the geological processes involved will, therefore, always depend on an external reference frame, and on the degree of subjectivity involved in our interpretation. Rarely, therefore, will geological interpretations be “correct”, and at least tow alternative answers will in most cases be available. Such alternative answers are, however, often avoided.In practical petroleum geology, these limitations to geological science appear to occur only in large‐scale interpretations, such as basin formaiton, tectonic driving forces and orogenesis. In regional and global geology, the reference framework is of primary importance, and will influence the underlying and resultant geological philosophy
THE AKAM OILFIELD, NIGER DELTA: GEOCHEMICAL STUDIES OF TERTIARY SHALES
Authors: Odigi M.I. 
Published: December 2007

Major, trace and rare‐earth elements show significant variations in concentration with depth. Akam Shales are characterised by relatively high contents of alumina, volaties and iron, and low contents of magnesia, lime, soda and potash. The major‐element chemistry is significantly different from that of the Akiri‐1 onshore oilwell, Niger Delta.Based on selected major‐and trace‐element concentrations, the Akam Shales have been discriminated into marine and non‐marine groups, and are found to be associated with calcareous sediments. This observation correlates with the Type II source rock, which is oil‐and gas‐proven in the Niger Delta.Elemental abundances could be explained on the basis of the terrigenous and authigenic constituents of the samples. Changes in elemental abundances and ratios were observed at a depth of about, 1,733 m; this could be correlated with a change in the source area, a facies change, or a change in depositional setting.
AN ISOLATED CARBONATE BANK IN THE ZECHSTEIN MAIN DOLOMITE BASIN, WESTERN POLAND
Authors: Peryt T. M. , Dyjaczynski K. 
Published: December 2007

Isolated carbonate banks in starved basins are very attractive targets for hydrocarbon prospecting. In the Zechstein (Late Permian) Main Dolomite (Ca2) Basin of Western Poland, six such banks or isolated platforms have been penetrated by wells, and gas and/or oil has been found in all of them. The largest is the Chartów Platform. which lies a few tens of kilometres from the edge of the carbonate shelf and shows well‐defined facies zonation, Three shallowing‐upward cycles may be distinguished in the bank‐edge sands, while the central (lagoonal) region and lower slope show a single deepening‐upward sequence. Local rapid subsidence, usually balanced by the rate of deposition, is inferred for the edge of the Chartów Platform: this subsidence was not balanced in other zones. The driving force for increased local subsidence may have been related to subtle block movements, and the break‐up of the P21 (Werra) evaporite platform. The rate of increased subsidence fluctuated: pulses of relatively rapid subsidence disturb the sequence, which was controlled by sea‐level fluctuations. Differential subsidence and sea‐level changes are common during the evolution of evaporite basins, and isolated platforms similar to the Chartów structure may be common in other evaporite basins, where isolated banks are located between the central and marginal areas.
PRE‐CREATACEOUS COALIFICATION IN SOUTHERN ISRAEL: CONTRIBUTION TO TIME‐TEMPERATURE COALIFICATION MODELLING
Authors: Feinstein S. , Kisch H. J. , Shagam R. 
Published: December 2007

The possibility that coal rank can remain “frozen” or static over a long period of time has important implications for time‐temperature coalification modelling. In the study area in southern Israel, the relationship between the 0.5‐0.8% Ro vitrinite iso‐reflectance contours and the strata (concordant in the Permian‐Jurassic sequence, discordant to the disconformably overlying Cretaceous) indicates that coalification within the Permo‐Trissic succession predated the development of the basal‐Cretaceous unconformity. The fact that coalification has remained static since at least Late Jurassic time, i.e. for more than 140 million yrs. suggests that the given coal rank was stable under the temperatures that subsequently prevailed. Examples of preserved pre‐deformation coalification are widespread elsewhere.Preservation of coal rank, static over long intervals due either to prolonged heating at constant temperature or too cooling, requires the existence of a state of coalification‐temperature pseudo‐equilibrium. Among the major implications is that the minimum temperature at which a certain coal rank cab be attined is the pseudo‐equilibrium temperature for this rank. Coalification would not proceed beyond this rank, regardless of the duration of heating, unless the temperature exceeded its pseudo‐equilibrium level. Hence, since coalification reactions are irreversible, a measured coal rank is actually a “minimum thermometer” for the maximum temperature experienced by the rock. This further implies that time‐temperature coalification modelling should be designed to allow for a discontinous process and for the slowing‐down of coalification rate with time.
THERMAL MATURITY DEVELOPMENT AND SOURCE‐ROCK OCCURRENCE IN THE RED SEA AND GULF OF ADEN
Authors: Barnard P. C. , Thompson S. , Bastow M. A. , Ducreux C. , Mathurin G. 
Published: December 2007

Detailed geochemical and geothermal studies have been carried out in the Red Sea and Gulf of Aden in order to understand the regional distribution of source rocks through time, and the effects of changing heat flow through time.These studies have shown the presence of generally thin developments of fair to very good quality source rocks. Most of the identified source rocks occur in syn‐rift sediments throughout the Red Sea area, but pre‐rift source‐rock occurrences have been identified in Yemen (Gulf of Aden). Somalia, and to a lesser extent in Egypt. Isolated occurrences of post‐rift source rocks have also been identified. The data can be interpreted in the regional context of the sedimentary facies of the region in order to predict possible geographic distribution of source rocks.Maturity gradients determined using vitrinite reflectivity and spore coloration range from low (often in post‐rift sections) to high (often in syn‐ and pre‐rift sections). The maturity gradients in many of the sections analysed show intersecting bi‐linear trends, suggesting very high palaeogeothermal gradients in sediments close to the rifting centres. In such areas, the oil and gas “windows” are relatively shallow and thin. In areas where crustal thickening has reduced heat flux. hydrocarbon generation may have occurred in the past, but has since ceased.The models derived during this project for source‐rock distribution and heat‐flow variations are consistent with the tectonic evolution of the basin, and show that there is good potential in parts of the study area for oil generation, accumulation and preservation in pre‐rift, syn‐rift as well as in post‐rift sediments.
PALAEOZOIC STRUCTURES AND OIL EXPLORATION PROSPECTS IN THE EASTERN TARIM BASIN, NW CHINA
Authors: Keming Yang , Guoyou Xu , Ping Jiang 
Published: December 2007

The Tabei Uplift in the northern Tarim Basin, the Tadong Depression in the eastern Tarim Basin, and the Tarim Central Uplift were formed as a result of mantle diapirism. Four stages in the geological development of this area can be recognized: an initial “embryonic” stage in the late Proterozoic; a “formational” stage in the Sinian; a “developmental” stage in the Early to mid‐Palaeozoic; and a “completion” stage in the late Palaeozoic. With long‐term Palaeozoic subsidence and well‐developed marine source rocks, the Tadong area is thought to be a promising source region for hydrocarbons. The Tabei and Central Uplifts, located respectively north and south of the Tadong Depression, are ancient, well‐preserved structures in which hydrocarbons may have accumulated, and could therefore constitute prospective areas for the location of “giant” oil‐ and gasfields in Palaeozoic sequences. Palaeozoic oil prospects have been confirmed in the Tabei area by the highly‐productive Sachan 2 well. It is expected that intensified exploration will result in the location of both oil‐ and gasfields in the Central Uplift.
A NEW SCHEME FOR THE FORMATION AND CLASSIFICATION OF BITUMENS
Authors: Klubov B. A. 
Published: December 2007

This paper discusses models of bitumen formation. Most liquid bitumens are formed during the middle stages of catagenesis (between approx. Ro equivalents of 0.4 and 1.15, respectively).“Progressive”naphthide formation is a process whereby organic matter and its derivatives gradually pass through a number of stages of alteration — three stages are generally recognized. By contrast, “regressive”naphthide formation is a “superimposed” process, involving microbial alteration and biochemical oxidation.In addition to the above two general processes, three other, less important schemes of naphthide formation are recognised:“Pyrodestructive bitumogenesis”results in the formation of “naphthoids”; these are bitumens generated close to an intruded heat source, which causes thermal destruction of organic matter.“Dynamic‐hydrothermal bitumogenesis”results in the generation of a complex group of bitumens, known as “naphthido‐naphthoids”, which are formed under conditions of dynamic metamorphism and hydrothermal activity accompanied by metasomatism. Thirdly, the process of “phase‐migrational” bitumogenesis results in the formation of two groups of bitumens: “asphaltenites” and “beta‐asphaltenites”.This paper summarizes the Author's views on bitumen formation, based on new geological and geochemical data.
ORIGIN OF THE MID‐YPRESIAN JIRANI DOLOMITE — A MAJOR RESERVOIR ROCK IN THE NW LIBYA OFFSHORE
Authors: Mriheel I.Y. , Anketell J.M. 
Published: December 2007

The Jirani Dolomite was formed during a major relative fall in sea‐level in middle Ypresian (early Eocene) times, in shallow, hypersaline lagoons on a restricted shallow platform, where supretidal and intertidal and semi‐arid to arid conditions prdominated. Localisation of the shallow logoonal facies to the region of the Jifarah Trough suggests that restriction was caused by downwarp relative to mild uplift of the Jifarah Platform to the north.Two main facies are recognised: and anhydritic dolomite facies, composed of dolomite and dolomitic limestone with anhydrite nodules; and a non‐anhydritic dolomite faices, composed of dolomite and dolomitic limestone only. Lithologic and petrographic evidence leads to the conclusion that anhydrite was also present in the non‐anhydritic dolomite facies initially, but was removed by dissolution processes. Petrographic studies show that dolomitisation proceeded in three stages. Stage I involved penecontemporaneous/early8 diagenetic dolomitisation of the precurosr limestones with gypsum/anhydrite under hypersaline seepage reflux conditions. Stage II dolomitisation, mainly confined to the non‐anhydritic dolomite facies, was probably formed in the mixing zone between meteoric and sea water, probably at shallow depths of burial. Stage III dolomitisation occured at depth in the late stage of basin evolution, causing some infilling of mouldic and vuggy porosity by coarsely crystalline, saddle dolomite. Evidence of mixing zone dolomitisation indicates that the Jirani Dolomite was exosed subaerially. Studies of the Metlaoui Group show that this event can be related to a major relative fall in sea level in early Lutetian times following deposition of the Jdeir Formation. Exposure of the deposits to flushing by meteoric waters explains the dissolution of the anhydrite from the non‐anhydritic dolomite faices, and the accentuation of the well‐development porosity in this facies, which make it one of the most important reservoir rocks in the offshore region.
NATURAL GAS IN NEW ZEALAND
Authors: van der Lingen G. J. 
Published: December 2007

ALTHOUGH THE FIRST (small) commercial hydrocarbon discovery in New Zealand was made in 1866, it was not until 1959 that modern exploration resulted in the onshore discovery of the gas‐condensate Kapuni field in the Taranaki Basin, followed in 1969 by the discovery of the giant offshore Maui gas‐condensate field. The last two decades have seen the development of these two fields, augmented by several smaller gas‐ and oilfields. An extensive gas pipeline system has been put into place in the North Island. The South Island gas needs are served by tankers and bottles.Of the many New Zealand sedimentary basins, the Taranaki Basin is the only productive one so far. As gas reserves are expected to run out by about 2006, New Zealand is faced with the challenge to find sufficient new deposits to replace the dwindling reserves. As newly‐discovered fields can take six to ten years to bring on‐stream, time is of the essence. Exploration is continuing at present, both on‐ and offshore, but statistically, based on past successes, may be of insufficient magnitude to meet the deadline. To prevent the disruption of supplies, and the closure of gas‐based industries, New Zealand needs a lot of luck in the next few years.
THE DISTRIBUTION OF OIL‐AND GASFIELDS IN RELATION TO SATELLITE IMAGE INTERPRETATION: AN EXAMPLE FROM THE POLISH EAST CARPATHIANS AND THE ADJACENT FOREDEEP
Authors: Karnkowski P. H. , Ozimkowski W. 
Published: December 2007

The Polish East Carpathians consist of a series of nappes which have been thrust northwards onto the Miocene sedimentary fill of the Carpathian Foredeep, a foreland basin located between the Meta‐Carpathian Swell to the north and the Carpathian orogen to the south. A total of 151 oil‐ and gasfields are present in the Polish Carpathians and the adjacent foredeep.In the Carpathians, all the oilfields are related to structural traps such as anticlinal folds which are frequently cut by faults, thrusts and décollement planes. In the Carpathian Foredeep, oil and gas accumulations are located both within the Neogene interval and in the pre‐Neogene basement. The most productive fields occur on the northern and southern margins of the Carpathian Foredeep; these locations received sandy detritus from the developing orogen to the south, and from the Meta‐Carpathian ridge to the north.In this paper, we compare the distribution of oil‐ and gasfields in the Polish Carpathians and the foreland basin to that of structural lineaments identified on Landsat imagery. Within the Carpathians, the lineaments are connected with fold axes, nappes, thrust slices and faults. In the Carpathian foredeep, by contrast, the lineaments must also be associated with faults, but no faults are indicated on surface geological maps. The simplest way to distinguish the faults is to interpret their presence in the pre‐Tertiary basement, and to project them into the Miocene cover.A satellite image of the study area was analysed independently by 40 different researchers, and the resulting interpretations were collated. With reference to this summary interpretation, we have attempted to analyse the spatial relationship between major lineaments and the distribution of oil‐ and gasfields in the study area.