bluuebunny/crossref_metadata_2025_split huggingface dataset:
A QUASI‐STATIC STUDY OF ACCOMMODATION IN AMBLYOPIA*
Authors: Ukai Kazuhiko , Ishhii Makiko , Ishikawa Satoshi 
Published: December 2007

Abstract— A method named quasi‐static recording of accommodation is introduced. While accommodative stimulus (AS) is slowly changed over a wide range with a constant velocity (0.2 D s‐1), accommodative response (AR) is continuously measured. AS and AR, respectively, are recorded on the abscissa and the ordinate of an x ‐ y recorder to produce a “quasi‐static” response/stimulus curve.This method was applied to 28 monocular amblyopic and formerly amblyopic subjects, and the findings were compared with those from their sound eyes. The recordings and subsequent analysis show reduced accommodative amplitude and reduced accommodative accuracy in amblyopic eyes, similar to those reported in previous static measurements of accommodation. In about a half of the amblyopic eyes, the recordings reveal that the fluctuations of accommodation are greater as the target becomes closer. Increased microfluctuation associated with a loss of sensitivity to change of contrast is discussed. This phenomenon suggests that increased microfluctuation is directly associated with reduced performance. In three recovered amblyopes, the accommodative functions were considerably reduced, while the other 10 subjects showed improved functions. It is suggested that, in some cases, the abnormal accommodation is the cause of the amblyopia.
Presbyopia correction and the accommodation in reserve
Authors: Millodot Michel , Millodot Susan 
Published: December 2007

One method of determining the additional correction for presbyopia suggests leaving a percentage of the amplitude of accommodation in reserve. The rationale for this assumption seems logical because using all of the available accommodation is not sustainable without discomfort. However there is no empirical evidence indicating what percentage of the amplitude of accommodation should actually be left in reserve. Common figures adopted have been one‐half and one‐third. In this investigation the percentage of accommodation used is deduced mathematically after having determined the following:1. The ‘add’ by the direct subjective clinical method.2. Measured the amplitude of accommodation.3. Measured the reading distance in 305 presbyopes ranging from 40 to 83 years of age.The results showed a small decline in the amplitude of accommodation up to the age of 52, after which age the measurements were scattered about a steady level. This finding suggests that after the age of 52 the results are based on the depth‐of‐focus of the eye. Females had slightly greater accommodation than males of the same age. The power of the add was significantly correlated to the age of the subject. The mean percentage of accommodation used for the 305 subjects was found to be 50.7%, thus confirming the rule of leaving half of the accommodation in reserve, although there were large variations: there were differences between males and females and with age the percentage of measured accommodation used, after having determined the correct add, diminished. Similarly the percentage of accommodation also decreased for shorter reading distances.
Do long wavelength pass filters improve low vision performance?
Authors: Leat Susan J. , North Rachel V. , Bryson Heather 
Published: December 2007

It has been suggested that the wearing of band‐pass tints may improve the contrast performance in certain ocular conditions. We examined this by measuring grating visual acuity (VA) for targets of various contrasts. The benefits of Corning CPF 511, 527 and 550 lenses, and neutral density (ND) filters were examined with and without the presence of glare.Generally, patients with anterior sector conditions showed improved performance with band‐pass filters (not with ND filters). It is suggested that the filter reduces the scatter within the ocular media. People with retinitis pigmentosa or diabetic retinopathy rarely benefited. The CPF 511 most frequently improved VA followed by CPF 527 and 550 respectively. We suggest that a condition of glare is incorporated when assessing suitability with tints.
Vision screening, eye examination and risk assessment of display screen users in a large regional teaching hospital
Authors: Jackson A. J. , Barnett E. S. , Stevens A. B. , McClure M. , Patterson C. , McReynolds M. J. 
Published: December 2007

SummaryIn January 1993 the Royal Group of Hospitals Trust, which employs approximately 5000 staff, implemented the Health and Safety (Display Screen Equipment) Northern Ireland Regulations (1992). During 1994 all regular display screen equipment users were offered a vision screening test. In total 571 employees were screened using computerized vision screening software (City Visual Systems Ltd). Risk assessments were completed for 293 display screen work‐stations. One hundred and twelve full eye examinations, carried out by optometrists, were performed on those who failed vision screening and on those who specifically requested an optometric assessment. Results indicate that whereas the proportion of users experiencing visual and general symptoms differed markedly from department to department (28–82%), the median number of individuals failing the screening test was 25% (range 9–40%), Those involved in uninterrupted display screen equipment work for prolonged periods reported visual and general work‐related symptoms twice as frequently as those who spent less time working with DSE. The outcome of full eye examinations confirmed that less than 5% of display screen users required spectacles solely for display screen use. Work‐station analysis indicated that ergonomic problems were common. The authors conclude that the successful management of health risks from display screen equipment requires simultaneous attention to work‐place design, working patterns and eye care.
STRUCTURAL DEVELOPMENT IN THE NORTHERN NORTH SEA
Authors: Hay J. T. C. 
Published: December 2007

The Northern North Sea basin is a relatively narrow, grabenal or half‐grabenal, northsouth trending feature. The trapping structures are tilted fault blocks. In the southern part of the basin these are mainly westwards tilted blocks formed by down to the east throw faults trending north‐south, parallel to the basin margins. This could fit with general plate tectonic theory, but in the northern part of the area this faulting is complicated by a pronounced NE‐SW trend. This is parallel to the old Caledonian trend and it is postulated that strike‐slip faulting may have been reactivated during the Mesozoic. This strike‐slip movement on the NE‐SW fault trend gave a tendency for individual fault block rotation resulting in a variety of block tilt directions in the northern part of the basin.The overall half‐graben feature probably started forming in early Triassic, but the faulting leading to the individual fault block formation mainly started during the Middle Jurassic, continuing through the Upper Jurassic. A further period of fault movement occurred during the Upper Cretaceous, but this is not associated with any tilt.
NATURAL GAS IN THE ARCTIC ISLANDS: DISCOVERED RESERVES AND FUTURE POTENTIAL
Authors: Waylett D. C. 
Published: December 2007

The Canadian Arctic Islands are underlain by the Cambrian‐Devonian Franklinian geosyncline, which is exposed in several areas, including the Parry islands fold belt, a part of the Paleozoic Arctic fold belt; and by the Mississippian‐Tertiary Sverdrup successor basin. Since 1969, one oilfield has been found in the Parry Islands fold belt and seven gasfields have been found in the Sverdrup basin. Only the gasfields are considered here.A total of 12.0 Tcf of proved and probable marketable gas reserves has been established in Early Jurassic and Triassic sandstones of the Sverdrup basin. These are mainly in structural traps, although some stratigraphic trapping has been established. Two of the fields–Hecla and Drake Point–are giants. Most of the gas reserves are in the Early Jurassic Borden Island Formation. Prospects for the future, largely offshore, are considered to be very good.
THE GEOLOGY OF THE AREA BETWEEN WADI WARDAN AND WADI GHARANDAL, EAST CLYSMIC RIFT, SINAI, EGYPT
Authors: Thiébaud C. E. , Robson D. A. 
Published: December 2007

The area between Wadi Wardan and Wadi Gharandal lies within the rift of the Gulf of Suez, the Clysmic rift, and is part of an elongated zone of outcropping Miocene deposits which show considerable persistence in a NNW to SSE direction, but which undergo frequent and rapid facies changes from W to E. The rocks are folded into a series of asymmetrical anticlinal flexures and synclines, sometimes faulted, whose axes trend NNW to SSE. They prove to be drape structures overlying pre‐Miocene blocks which are generally tilted. Block faulting began during Oligocene times and persisted through Miocene into the post‐Miocene period. The blocks dip westwards, towards the centre of the rift, and are generally bounded by antithetic faults. The structures described in this paper are typical for the whole region of the Clysmic rift. There are no beds of Oligocene age and no igneous rocks, either of extrusive or of intrusive origin, occur in association with Miocene or later deposits.The area has proved to be important economically. Three oilfields have been discovered there–Sudr (which lies some kilometres N of Wadi Wardan) in 1946, Ras Metarma in 1948, and Asl in 1949. In each case, the reservoir rock is found near the base of the Miocene or in Eocene limestone at or near the top of a Wdipping block of pre‐Miocene strata. Marls and gypsum or anhydrite deposits invariably form the capping rock.
PETROLEUM GEOLOGY IN THE PALEOZOIC CLASTICS OF THE MIDDLE AMAZON BASIN, BRAZIL
Authors: Carozzi Albert V. 
Published: December 2007

Paleoenvironmental maps of all the stratigraphic units of the Middle Amazon Basin from Ordovician to Early Carboniferous are analysed in terms of their source‐rock and reservoir potentials. These maps were obtained by applying the following techniqes; detailed petrography of diamictites, sandstones and siltstones including measurements of index of clasticity; analysis of early and late diagenetic cementation processes; environmental interpretation of sedimentary structures; geochemistry of trace elements and lateral variations of clay mineral assemblages based on X‐ray diffraction data. Five distinct sedimentary models were recognized. Fluvio‐deltaic model consisting of fluvial, deltaic, distal deltaic and offshore subenvironments. Tidal flat model consisting of marshes, intertidal flat, shoreface and offshore subenvironments. Beach model consisting of dunes (inferred), beach, shoreforce and offshore subenvironments. Glacial model (Nhamundá time, Early Silurian), consisting of glacial (tillites), fluvial, beach, shoreface and offshore subenvironments. Glacial model (Curiri time, Late Devonian) consisting of glacial (tillites with subglacial sandstone channels and interglacial braided streams), shoreface and offshore subenvironments.From the association of these depositional models, the direction and intensity of the supply of coarse clastics was determined in a semi‐quantitative manner for each stratigraphic unit. The time andspace distribution of the detritalsupplies and of the areas of coarse clastic sedimentation indicates a continuous synsedimentary tectonic control of the depocenters by the differential subsidence of the underlying Precambrian basement in the shape of large blocks limited by a system of NW‐SE and NE‐SW lineaments. By using an index of synsedimentary tectonic activity it is possible to define three major episodes of coarse clastic sedimentation which have the best reservoir potential: Early Silurian fluvio‐glacial systems, Early Devonian progmding deltas and Late Devonian fluvio‐glacial systems. The tmps for hydrocarbons are mainly stmtigmphic but enhanced by the weak structures of the basin and result from the relationship between the coarse clastics and two intervening sequences of mature black shales.
RELATIONSHIP OF FACIES AND RESERVOIR QUALITY IN ROTLIEGENDES DESERT SANDSTONES, SOUTHERN NORTH SEA REGION
Authors: Nagtegal P. J. C. 
Published: December 2007

permian Rotliegendes desert sandstones cored in two wells in the southern North Sea were grouped as wadi, adhesion‐ripple, dune‐base and dune‐top sandstones on the basis of sedimentary structure and grains‐size characteristics. The porosities of these sandstones differ significantly. Those of wadi origin have the lowest values (φav.=5.5%) and the dune‐top sandstones have the highest (φav.=14.6%). The present study is amied at explaining these differences. The sandstones, which have been buried to a depth of approx. 4.000 m. have a complex diagenetic history marked by envirnment‐and depth‐related changes. Apart from authigenic ferric oxide, dolomite, anhydrite, K‐feldspar and quartz, they are characterised by well‐developed pressure solution and well‐crystallised authigenic illite and chlorite. The chlorite has a pore‐bridging growth habit which disturbs the porosity‐permeability relationship.On the basis of thin‐section petrographic point‐count analyses and porosity and permeability measurements, and by means of multivariate analysis, the nature and the small‐scale distribution of sorting in each of the sandstone facies types are ultimatly isolated as the main variables explaining the porosity differences. These sandstones thus display porosity differences which correlate with primary sedimentary structure. This relationship was not destroyed even at deep burial and marked diagenetic change.
UTILIZATION AND DOCUMENTATION OF VERTICAL OIL MIGRATION IN DEEP BASINS
Authors: Price Leigh C. 
Published: December 2007

Use of the model of a hot, deep, origin of oil places rigid constraints on the migration and entrapment of crude oil. Specifically, oil originating from depth migrates vertically up faults and is emplaced in traps at shallower depths. Review of petroleum‐producing basins worldwide shows oil occurrence in these basins conforms to the restraints of this hypothesis. Most of the world's oil is found in the very deepest sedimentary basins, and production over or adjacent to the deep basin is cut by, or directly updip from, faults dipping into the basin deep. Generally, the greater the fault throw, the greater the reserves.Fault‐block highs next to deep sedimentary troughs are the best target areas by the present concept. Traps along major basin‐forming faults are quite prospective.The structural style of a basin governs the distribution, types, and amounts of hydrocarbons expected, and hence the exploration strategy. Production in delta depocenters (Niger) is in structures cut by or updip from major growth faults, and structures not associated with such faults are barren. Production in block‐fault basins in on horsts next to deep sedimentary troughs (Sirte, North Sea). In basins whose sediment thickness, structure and geologic history are known to a moderate degree, the main oil occurrences can be specifically predicted by analysis of fault systems and possible hydrocarbon migration routes.Use of the concept permits the identification of significant targets, which have either been downgraded or ignored in the past, such as production in or just updip from thrust belts, stratigraphic traps over the deep basin asociated with major faulting, production over the basin deep, and regional stratigraphic trapping updip from established production along major fault zones.
COMPARISON OF POROSITY‐DEPTH RELATIONSHIPS OF SHALE AND SANDSTONE*
Authors: Magara Kinji 
Published: December 2007

The rate of shale compaction or porosity reduction decreases with increase in burial or compaction. This may be caused by decreasing shale permeability and increasing water viscosity, thus decreasing rate of fluid expulsion with increasing compiction. For a given increase in overburden pressure, the pressure or stress applied to a given grain‐to‐grain contact area decreases with burial becaused the contact area increases with compaction and concomitant grain deformation. This may also cause the reduced rate of compaction with increase in burial. The above abservations may suggest that the shale compaction is primarily controlled by physical forces of sedimentary rocks.On the contrary, the rate of sandstone porosity reduction is known to be relatively constant throughout the burial diagenetic history in many regions provided ther was no significant secondary porosity developed by leaching and fracturing. For a given increase in overburden pressure, the grain‐to‐grain contact area. Yet, rate of porosity reduction for the sandstones is realtively constant, whether they are at a shallow or deep burial depth. This suggests that, for the sandstones, the physical forces have been of secondary importance in reducing the porosity. Chemical and mineralogical agents are believed to have been more significant in sandstones. Numerous regional petrographic studies confiirm the importance of diagenetic cements.
POROSITY MODELS AND OIL EXPLORATION OF AMAPÁ CARBONATES, PALEOGENE, FOZ DO AMAZONAS BASIN, OFFSHORE NW BRAZIL
Authors: Carozzi Albert V. 
Published: December 2007

The extensive, thick Paleogene carbonate platform (Amapá Formation) of the Foz do Amazonas Basin, probably the largest coralgal‐foraminiferal platform of the geological record, developed through four depositional cycles expressing global eustatic changes of sea level. It shows five environmental belts: slope, apron, coralgal platform, large foraminifer shoal, finger coral bank and restricted lagoon, all of which associate bioaccumulated and bioclastic microfacies. At all times, a terrigenous environment consisting of fan deltas and lagoonal fine‐grained clastics existed immediately behind the carbonate platform and was connected with the open ocean by transverse troughs filled with shales and carbonate olistoliths. This combination of clastic and carbonate environments is unique in the geological record, and today only the Belize Shelf displays comparable conditions.The patterns of distribution of porous carbonates are different for each depositional cycle and the percentage of porous carbonates increases from cycle II to cycle IV. This indicates distinct and successive reservoir conditions generated during episodes of subaerial exposure of an expanding platform by large‐scale circulation systems at the end of each depositional cycle when high‐stand sea level changed to low‐stand. Porosity is mainly enlarged interparticle and moldic with a minor contribution of intercrystalline type related to dolomitization by mixing freshwater‐marine waters. It is not known to what extent the terrigenous environment contributed to the meteorically supplied groundwater system and related dolomitization, but the scale of the circulation is comparable to that presently displayed by Florida and Yucatan.The possibility of hydrocarbon flushing from such carbonate reservoirs is an important factor in the evaluation of the petroleum potential of the Amapá carbonates.
IMPACT CRATERS:IMPLICATIONS FOR BASEMENT HYDROCARBON PRODUCTION
Authors: Donofrio Richard R. 
Published: December 2007

The impact cratering process results in unique structures and extensive fracturing and brecciation of the target rock which can be conducive to hydrocarbon accumulations. Examination of Viewfield and Red Wing Creek oil pools in North America reveals that they may have been formed by meteoritic impact in Paleozoic sediments. Additional hydrocarbon traps have most likely been produced by impact but have not been recognized as such because geologists are generally not familiar with crater structures and shock‐metamorphic effects in rocks. It is proposed that petroliferous basement impact craters also exist and that despite arguments to the contrary, at least one may have already been found. Further discoveries are severely limited because of conservative exploration procedures, which characteristically avoid penetrating crystalline basement.Core analysis from several large impact sites developed in crystalline rocks reveals that while permeability factors are marginal, the reservoir potential of these craters exceeds those of many of the largest known hydrocarbon accumulations. Preservation age studies of craters in conjunction with size frequency distribution curves implies that many will have been buried before erosional eradication. As with normally‐fractured and brecciated basement areas, some will have accumulated hydrocarbons. In addition to classical source rocks flanking or overlying these potential reservoirs, recycled kerogen and the possibility of inorganic sources are also considered. A basement impact crater may afford a unique way of testing the inorganic hydrocarbon proposals.
ON THE THEORY OF GROWTH FAULTING PART II(b):GENESIS OF THE “UNIT”*
Authors: Crans W. , Mandl G. 
Published: December 2007

This paper comprises a continuation of the second section of a detailed and riegorous geomechenical analysis of the stability of overpressured, gently‐sloping sediment layers presented in the Journal of Petroleum Geology 2, 3, 1980 and 3,2, 1980. The authors continue to describe the delta model which they use to explain and permit quantitative reproduction of the main features associated with growth faulting; part II(a) considered stress equilibrium, related stress equations, types of overpressure, the representation of the stress state in Mohr space and the plastic/elastic stated of frictional materials in long, fluid‐filled layers. The present article continues with the analysis, with a numerical and analytical examination of slip lines and considerations of plastic, flow and slip.Peak‐strenght phenomena and the effect of purely‐cohesive materials on the theory conclcude the paper in our next issue, together with a discussion of the behaviour of watersaturated soils(as opposed to theoretical solid material with elastic and plastic properties), and the six major conclusions which can be drawn from the work.
LITHOFACIES DISTRIBUTION OF THE PERMIAN‐TRIASSIC ROCKS IN THE MIDDLE EAST
Authors: Sharief Farooq A. 
Published: December 2007

The lithofacies distribution of the Permian‐Triassic sequence across the Middle East region shows a great diversity of depositional sedimentary facies laterally as well as vertically. During Permian‐Middle Triassic time, a clastic‐carbonate shelf facies characterizes most of the Middle East region. This platform facies is marked by a number of depositional sedimentary facies which is related to a wide variety of environments, from non‐marine, supratidal and restricted marine shelf to open‐sea and deeper‐shelf deposition.The distribution of the Upper Triassic lithofacies is marked by sharply‐differentiated depositional patterns. Except for Iran, N Iraq, SE Turkey and central Syria, the passage from the Middle Triassic to the Upper Triassic in the region is marked either by non‐deposition or continental strata, or carbonate‐evaporite sequence. Marine, carbonate and shale deposits of open‐shelf facies continued to be formed in W Iran, N Iraq and SE Turkey. A large amount of richly fossiliferous clastic, neritic deposits accumulated in central and E parts of Iran. In contrast, a terrigenous‐flysch‐like sequence continued to accumulate in the extreme NE Iran since early Triassic time.