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Oman
Selected AbstractsTRACING BACK THE ORIGIN OF THE INDO-PACIFIC MOLLUSC FAUNA: BASAL TRIDACNINAE FROM THE OLIGOCENE AND MIOCENE OF THE SULTANATE OF OMANPALAEONTOLOGY, Issue 1 2008MATHIAS HARZHAUSER Abstract:, Two new tridacnine species are described from the Chattian and Aquitanian of the Arabian Peninsula. For these, the new names Omanidacna eos gen. et sp. nov. and Tridacna evae sp. nov. are erected. Omanidacna is interpreted as an Oligocene ancestor of Hippopus, being the oldest record of this tridacnine lineage. The Aquitanian Tridacna evae is the first occurrence of the genus Tridacna. These Arabian taxa imply that the modern tridacnine lineages are rooted in the Palaeogene and early Neogene of the East African-Arabian Province, although their Eocene ancestors, such as Byssocardium, are Western Tethyan taxa. During the Neogene they successfully settled the Indo-Polynesian Province and became typical elements of the entire Indo-West Pacific Region. The tridacnines are thus an example of a successive transformation and gradual eastward dispersal of an originally Tethyan element contributing to late Neogene diversity in the Indo-West Pacific. [source] A Pride of Museums in the Desert: Saudi Arabia and the "Gift of Friendship" ExhibitionCURATOR THE MUSEUM JOURNAL, Issue 1 2005John Coppola ABSTRACT The task of developing and presenting an exhibition at the King Abdul Aziz Historical Center in Riyadh, Saudi Arabia illustrates the challenges of museum work in a global environment filled with widely differing social, cultural, political, and professional norms. The exhibition, The Gift of Friendship, was largely drawn from the collections of the Franklin D. Roosevelt Library, in New York State. Saudi Arabia and its neighboring countries view museums as a source of national pride and public engagement, and frequently draw on Western expertise in building them. There are implications for exhibition development and interpretation in a society undergoing rapid modernization, but also one noted for an aversion to social science research. A postscript looks at museum trends in Oman, after 9/11 and the Iraq war. [source] Increasing prevalence of diabetes mellitus in OmanDIABETIC MEDICINE, Issue 11 2002J. A. Al-Lawati Abstract Aims To determine the prevalence of diabetes mellitus and impairedfasting glucose by age, gender, and by region and compare resultswith the 1991 survey; and estimate previously undiagnosed diabetesmellitus in the Omani population. Methods Cross-sectional survey containing a probability random sample of5838 Omani adults aged , 20 years. Diabetesand impaired fasting glucose (IFG) were assessed by fasting venous plasmaglucose using 1999 World Health Organization's diagnosticcriteria (normoglycaemia < 6.1 mmol/l, IFG , 6.1 but < 7 mmol/l,and diabetes , 7 mmol/l). The 1991 surveywas reanalysed using the same diagnostic criteria, and results werecompared. Results In 2000, the age-adjusted prevalence of diabetes among Omanis aged30,64 years reached 16.1% (95% confidenceinterval (CI) 14.7,17.4) compared with 12.2% (95% CI11.0,13.4) in 1991. IFG was found among 7.1% (95% CI6.2,8.1) of males and 5.1% (95% CI 4.4,6.0)of females. Generally, diabetes was more common in urban then ruralregions. Only one-third of diabetic subjects knew that they haddiabetes. Nearly half of the study population had a body mass index > 25 kg/m2. Conclusions The prevalence of diabetes is high in Oman and has increasedover the past decade. The high rate of abnormal fasting glucosetogether with high rates of overweight and obesity in the population makeit likely that diabetes will continue to be a major health problem inOman. Primary prevention programmes are urgently needed to counteract majorrisk factors that promote the development of diabetes. Diabet. Med. 19, 954,957 (2002) [source] Late Quaternary vadose carbonate diagenesis in coastal and desert dune and beach sands: is there a palaeoclimatic signal?EARTH SURFACE PROCESSES AND LANDFORMS, Issue 12 2004Sue McLaren Abstract A study of the variation in cement amounts in aeolianite and sandy beach calcarenites that range in age from Holocene to Last Interglacial is used to assess whether a palaeoclimatic control on vadose diagenesis can be identi,ed. Examples are taken from modern-day arid to subhumid settings and represent a geographical distribution ranging from Libya and Oman, to the Mediterranean, the Caribbean and Mexico. The results indicate that a palaeoclimatic signal can be identi,ed in some deposits. However, in other sediments there is substantial variability in mean cement abundance within deposits as well as between these sand bodies. Moreover, many of the better cemented sediments are located in areas where there is accelerated diagenesis, such as in the sea spray zone, close to the groundwater table or near to a palaeosurface, rather than in climatically wet regions. The inference is that palaeoclimatic interpretations are substantially complicated by other factors that affect diagenetic processes and change. Therefore caution is needed when studying the role of climate in vadose diagenesis in the light of the effects of other intrinsic and extrinsic controls. This paper does not aim to provide a de,nitive comparison of sites from different climatic zones. The approach taken here is: (a) to see if there is an overall palaeoclimatic signal in the samples studied; (b) to use examples to illustrate how explanations/controls other than those relating to climate can account for the variabilities observed; and (c) if there is a climatic effect, to see if it is the main over-riding control on vadose diagenesis. The conclusions drawn from this research highlight that it is possible to misinterpret evidence if the study is approached with preconceived notions of simplistic relationships between diagenesis and climate. Copyright © 2004 John Wiley & Sons, Ltd. [source] Profile of the climate change in the Kingdom of BahrainENVIRONMETRICS, Issue 8 2003W. E. Alnaser Abstract Long-term meteorological data from the Kingdom of Bahrain (1902 to 2001), along with other data from the Sultanate of Oman and the Kingdom of Saudi Arabia, were used to study the profile and the characteristics of the climate changes in the Kingdom of Bahrain. This article illustrates the possible effects of several factors, such as greenhouse gases (GHG), sunspot number, cosmic ray flux, planet conjunctions, the Earth's magnetic field, as well as volcanic eruption, on the profile of the climate change. In general, we found that the temperature variations, to a certain extent, are associated with the cyclic variations in sunspot number (the 11-year cycle), which in turn affect the pattern of the cosmic ray flux due to the distortion of the interplanetary magnetic field. The latter is believed to influence cloud formation. In addition, the discrepancy in the climate change pattern in Bahrain was also attributed to the combined effect of the high local level of CO2 emissions as well as that of other cooling gases in the region. Copyright © 2003 John Wiley & Sons, Ltd. [source] Composition and antimicrobial activity of the essential oil of Pluchea arabica from OmanFLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2006Fakhr Eldin O. Suliman Abstract Fresh twigs of Pluchea arabica (Boiss) Qaiser & Lack (Compositae) were steam-distilled and the essential oil obtained was analysed by GC,MS. Forty-four components were identified, accounting for 93.2% of the total components detected. The major constituents were , -cadinol (26.8%), 9-(1-methylethylidene)-bicyclo[6.1.0]nonane (10.8%), caryophyllene oxide (10.0%), methyleugenol (9.2%) and , -caryophyllene (6.9%). The essential oil of P. arabica was active against Staphylococcus aureus (ATCC 29213), Candida albicans (ATCC 10231) and Bacillus subtilis when tested against seven organisms. The oil was found to be less fragrant than Ocimum forskaoli oil in an odour test. Copyright © 2006 John Wiley & Sons, Ltd. [source] Evidence for an abrupt climatic change at 8700 14C yr B.P. in rockshelters and caves of Gebel Qara (Dhofar-Oman): Palaeoenvironmental implicationsGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 6 2005Mauro Cremaschi Geoarchaeological research on the sedimentary fill of rockshelters and caves in the Gebel Qara (Dhofar, Southern Oman) has revealed the onset of heavy rains at 8700 yr B.P. These rains, produced by strengthening of the Southwest monsoon, abruptly altered the dry environment dominant in the area since the Pleistocene-Holocene transition. Comparison of cave fills from the southern and northern fringes of the Gebel Qara indicates that the monsoon effects were limited to the southern and central part of the mountain range, directly facing the sea, and did not penetrate into the Nejd Desert. © 2005 Wiley Periodicals, Inc. [source] Desert environments: landscapes and stratigraphyGEOLOGY TODAY, Issue 5 2009Peter G. Fookes It is common to think of hot deserts, i.e. hot arid or dry lands, as areas of little rain situated in the middle parts of the world, that are simply ,just there'. However, most of the world's deserts have a long geological history, sometimes of 50 million years or more and ways have been developing for some time now, particularly from geomorphological studies, of not only erecting the law of superposition of strata for the desert but also ,absolute' dating. The authors have often worked commercially in deserts world-wide but their recent experiences in the Oman have brought home to them the excellent work that has been going on in the last two or three decades in evaluating the geological history of deserts. The Oman experience is described in a feature in the next issue. [source] Pan-glacial,a third state in the climate systemGEOLOGY TODAY, Issue 3 2009Paul F. Hoffman Radiative energy-balance models reveal that Earth could exist in any one of three discrete climate states,,non-glacial' (no continental ice-sheets), ,glacial-interglacial' (high-latitude ice-sheets) or ,pan-glacial' (ice-sheets at all latitudes),yet only the first two were represented in Phanerozoic time. There is mounting evidence that pan-glacial states existed at least twice in the Cryogenian (roughly 750,635 Ma), the penultimate period of the Neoproterozoic. Consensus is lacking on whether the world ocean was fully glaciated (,snowball' model) or largely unglaciated (,slushball' model). The first appearances of multicellular animal fossils (diapause eggs and embryos in China, and sponge-specific biomarkers in Oman), being closely associated with the last pan-glacial state, revive speculation that environmental forces had a hand in the origin of metazoa. [source] Low-frequency passive seismic experiments in Abu Dhabi, United Arab Emirates: implications for hydrocarbon detectionGEOPHYSICAL PROSPECTING, Issue 5 2010Mohammed Y. Ali ABSTRACT Low-frequency passive seismic experiments utilizing arrays of 3-component broadband seismometers were conducted over two sites in the emirate of Abu Dhabi in the United Arab Emirates. The experiments were conducted in the vicinity of a producing oilfield and around a dry exploration well to better understand the characteristics and origins of microtremor signals (1,6 Hz), which had been reported as occurring exclusively above several hydrocarbon reservoirs in the region. The results of the experiments revealed that a strong correlation exists between the recorded ambient noise and observed meteorological and anthropogenic noises. In the frequency range of 0.15,0.4 Hz, the dominant feature is a double-frequency microseism peak generated by the non-linear interactions of storm induced surface waves in the Arabian Sea. We observed that the double-frequency microseism displays a high variability in spectral amplitude, with the strongest amplitude occurring when Cyclone Gonu was battering the eastern coast of Oman; this noise was present at both sites and so is not a hydrocarbon indicator. Moreover, this study found that very strong microtremor signals in the frequency range of 2,3 Hz were present in all of the locations surveyed, both within and outside of the reservoir boundary and surrounding the dry exploration well. This microtremor signal has no clear correlation with the microseism signals but significant variations in the characteristics of the signals were observed between daytime and nighttime recording periods that clearly correlate with human activity. High-resolution frequency-wavenumber (f - k) spectral analyses were performed on the recorded data to determine apparent velocities and azimuths of the wavefronts for the microseism and microtremor events. The f - k analyses confirmed that the double-frequency microseism originates from wave activity in the Arabian Sea, while the microtremor events have an azimuth pointing towards the nearest motorways, indicating that they are probably being excited by traffic noise. Results drawn from particle motion studies confirm these observations. The vertical-to-horizontal spectral ratios of the data acquired in both experiments show peaks around 2.5,3 Hz with no dependence on the presence or absence of subsurface hydrocarbons. Therefore, this method should not be used as a direct hydrocarbon indicator in these environments. Furthermore, the analyses provide no direct evidence to indicate that earthquakes are capable of stimulating the hydrocarbon reservoir in a way that could modify the spectral amplitude of the microtremor signal. [source] Distance separated simultaneous sweeping, for fast, clean, vibroseis acquisitionGEOPHYSICAL PROSPECTING, Issue 1 2010Jack Bouska ABSTRACT Distance separated simultaneous sweeping DS3 is a new vibroseis technique that produces independent records, uncontaminated by simultaneous source interference, for a range of offsets and depths that span all target zones of interest. Use of DS3 on a recent seismic survey in Oman, resulted in a peak acquisition rate of 1024 records per hour. This survey employed 15 vibrators, with a distance separation of 12 km between simultaneous active sources, recorded by 8000 active channels across 22 live lines in an 18.5 km × 11 km receiver patch. Broad distribution of simultaneous sources, across an adequately sized recording patch, effectively partitions the sensors so that each trace records only one of the simultaneous sources. With proper source separation, on a scale similar to twice the maximum usable source receiver offset, wavefield overlap occurs below the zone of interest. This yields records that are indistinguishable from non-simultaneous source data, within temporal and spatial limits. This DS3 technique may be implemented using a wide variety of acquisition geometries, optimally with spatially large recording patches that enable appropriate source separation distances. DS3 improves acquisition efficiency without data quality degradation, eliminating the requirement for special data processing or noise attenuation. [source] The 3D shear experiment over the Natih field in Oman: the effect of fracture-filling fluids on shear propagationGEOPHYSICAL PROSPECTING, Issue 2 2001C.M. Van Der Kolk This is the final paper in a series on the 3D multicomponent seismic experiment in Oman. In this experiment a 3D data set was acquired using three-component geophones and with three source orientations. The data set will subsequently be referred to as the Natih 9C3D data set. We present, for the first time, evidence demonstrating that shear waves are sensitive to fluid type in fractured media. Two observations are examined from the Natih 9C3D data where regions of gas are characterized by slow shear-wave velocities. One is that the shear-wave splitting map of the Natih reservoir exhibits much larger splitting values over the gas cap on the reservoir. This increase in splitting results from a decrease in the slow shear-wave velocity which senses both the fractures and the fracture-filling fluid. Using a new effective-medium model, it was possible to generate a splitting map for the reservoir that is corrected for this fluid effect. Secondly, an anomaly was encountered on the shear-wave data directly above the reservoir. The thick Fiqa shale overburden exhibits a low shear-wave velocity anomaly that is accompanied by higher shear reflectivity and lower frequency content. No such effects are evident in the conventional P-wave data. This feature is interpreted as a gas chimney above the reservoir, a conclusion supported by both effective-medium modelling and the geology. With this new effective-medium model, we show that introduction of gas into vertically fractured rock appears to decrease the velocity of shear waves (S2), polarized perpendicular to the fracture orientation, whilst leaving the vertical compressional-wave velocity largely unaffected. This conclusion has direct implications for seismic methods in exploration, appraisal and development of fractured reservoirs and suggests that here we should be utilizing S-wave data, as well as the conventional P-wave data, as a direct hydrocarbon indicator. [source] Eolian Transport of Geogenic Hexavalent Chromium to Ground WaterGROUND WATER, Issue 1 2010Warren W. Wood A conceptual model of eolian transport is proposed to address the widely distributed, high concentrations of hexavalent chromium (Cr+6) observed in ground water in the Emirate of Abu Dhabi, United Arab Emirates. Concentrations (30 to more than 1000 ,g/L Cr+6) extend over thousands of square kilometers of ground water systems. It is hypothesized that the Cr is derived from weathering of chromium-rich pyroxenes and olivines present in ophiolite sequence of the adjacent Oman (Hajar) Mountains. Cr+3 in the minerals is oxidized to Cr+6 by reduction of manganese and is subsequently sorbed on iron and manganese oxide coatings of particles. When the surfaces of these particles are abraded in this arid environment, they release fine, micrometer-sized, coated particles that are easily transported over large distances by wind and subsequently deposited on the surface. During ground water recharge events, the readily soluble Cr+6 is mobilized by rain water and transported by advective flow into the underlying aquifer. Chromium analyses of ground water, rain, dust, and surface (soil) deposits are consistent with this model, as are electron probe analyses of clasts derived from the eroding Oman ophiolite sequence. Ground water recharge flux is proposed to exercise some control over Cr+6 concentration in the aquifer. [source] On the technical feasibility of gas turbine inlet air cooling utilizing thermal energy storageINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 5 2006Y. H. Zurigat Abstract The potential of using thermal energy storage (TES) in the form of ice or chilled water to cool gas turbine inlet air is evaluated for a remote oil field location in the Sultanate of Oman using local hourly typical meteorological year weather data. It is found that under the conditions investigated seasonal TES in chilled water storage tanks or ice bins for the location considered is prohibitively expensive and thus not recommended. Application of partial TES option shows that the cool storage does not result in any noticeable reduction in the chiller size. Hence, TES whether seasonal, partial, or full storage is not a viable option for the considered location, especially in the absence of time-of-use utility rate structure. Copyright © 2005 John Wiley & Sons, Ltd. [source] A step-by-step application of Sandia method in developing typical meteorological years for different locations in OmanINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 8 2005Naseem M. Sawaqed Abstract This paper reports on the development of typical meteorological years (TMYs) for seven different locations in Oman based on measured meteorological data. Depending on the availability of data the TMYs developed using Sandia method used data covering 7,17 years. The method as implemented here in a step-by-step procedure with illustrations is made simple. The procedure described herein is computerized and can handle any number of data sets in an easy-to-use manner. This should facilitate the development of TMYs for any location where enough data is available. Sensitivity analysis of different weights assigned to different weather parameters shows that Sandia method is highly affected by solar flux even if its weight is reduced by half while the weights of other parameters such as temperature, wind, and relative humidity have less impact on the selection of TMY. Copyright © 2005 John Wiley & Sons, Ltd. [source] Human resource development in the Sultanate of OmanINTERNATIONAL JOURNAL OF TRAINING AND DEVELOPMENT, Issue 3 2002Pawan S. Budhwar This study explores the scenario of human resource development (HRD) in the Sultanate of Oman. The investigation was conducted with the help of a questionnaire survey in stateowned enterprises (SOEs). The research findings highlight an increased emphasis on HRD initiatives at a national level in Omani firms. There is a significant degree of awareness among the top managers regarding the benefits of a strategic approach to HRD. Despite all this, the implementation of HRD programmes has not been particularly successful. This is because the state has not been able to develop the skills and competencies of the Omani workforce to the levels required under the sixth national five,year plan. The article makes a number of recommendations in this regard. It also highlights key research areas for further examination. [source] Leaf Decomposition in a Mountain Stream in the Sultanate of OmanINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 1 2009Maha Al-Riyami Abstract Decomposition of Juglans regia leaves was studied in fine and coarse mesh bags in a permanent mountain stream in Oman. A rapid initial mass loss, attributed to leaching, was followed by a more gradual decline. Daily exponential decay rates (k) calculated over 32 days were 0.011 (fine mesh litter bags) and 0.014 (coarse mesh litter bags). The difference between bag types was not significant, suggesting limited impact of leaf-shredding invertebrates. Ergosterol levels on leaves from fine mesh bags peaked at 0.3 mg g,1 AFDM after 16 days of stream exposure. During the experimental period, which followed the annual leaf fall, the concentration of aquatic hyphomycete conidia in the stream varied between 82 and 1362 l,1. Based on the morphology of conidia found in the water column or released from leaves, we identified 14 species of aquatic hyphomycetes. Tetracladium apiense was the most common taxon (62.2% of conidia in water column during the field experiment). Three other Tetracladium species contributed another 8%. Plating out leaf particles yielded common epiphytic taxa such as Alternaria sp., Aureobasidium pullulans and Phoma sp. The measured metrics of leaf decay in this desert stream fall within the range of values observed in temperate and tropical streams, with clear evidence for an early leaching phase, and no evidence of a strong impact of leaf shredders. The community of aquatic hyphomycetes appears impoverished. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Phylogeography of the introduced species Rattus rattus in the western Indian Ocean, with special emphasis on the colonization history of MadagascarJOURNAL OF BIOGEOGRAPHY, Issue 3 2010Charlotte Tollenaere Abstract Aim, To describe the phylogeographic patterns of the black rat, Rattus rattus, from islands in the western Indian Ocean where the species has been introduced (Madagascar and the neighbouring islands of Réunion, Mayotte and Grande Comore), in comparison with the postulated source area (India). Location, Western Indian Ocean: India, Arabian Peninsula, East Africa and the islands of Madagascar, Réunion, Grande Comore and Mayotte. Methods, Mitochondrial DNA (cytochrome b, tRNA and D-loop, 1762 bp) was sequenced for 71 individuals from 11 countries in the western Indian Ocean. A partial D-loop (419 bp) was also sequenced for eight populations from Madagascar (97 individuals), which were analysed in addition to six previously published populations from southern Madagascar. Results, Haplotypes from India and the Arabian Peninsula occupied a basal position in the phylogenetic tree, whereas those from islands were distributed in different monophyletic clusters: Madagascar grouped with Mayotte, while Réunion and Grand Comore were present in two other separate groups. The only exception was one individual from Madagascar (out of 190) carrying a haplotype that clustered with those from Réunion and South Africa. ,Isolation with migration' simulations favoured a model with no recurrent migration between Oman and Madagascar. Mismatch distribution analyses dated the expansion of Malagasy populations on a time-scale compatible with human colonization history. Higher haplotype diversity and older expansion times were found on the east coast of Madagascar compared with the central highlands. Main conclusions, Phylogeographic patterns supported the hypothesis of human-mediated colonization of R. rattus from source populations in either the native area (India) or anciently colonized regions (the Arabian Peninsula) to islands of the western Indian Ocean. Despite their proximity, each island has a distinct colonization history. Independent colonization events may have occurred simultaneously in Madagascar and Grande Comore, whereas Mayotte would have been colonized from Madagascar. Réunion was colonized independently, presumably from Europe. Malagasy populations may have originated from a single successful colonization event, followed by rapid expansion, first in coastal zones and then in the central highlands. The congruence of the observed phylogeographic pattern with human colonization events and pathways supports the potential relevance of the black rat in tracing human history. [source] The tripartite biogeographical index: a new tool for quantifying spatio-temporal differences in distribution patternsJOURNAL OF BIOGEOGRAPHY, Issue 4 2006Tom Schils Abstract Aims, First, to develop an index that quantifies biogeographical patterns based on the basic descriptors of presence/absence distribution patterns (F, frequency; C, connectivity; G, grouping). Second, to test the proposed biogeographical index on a data set of macrophyte communities in the Arabian Sea using distribution data of macro-algae and seagrasses throughout the Indian Ocean. Location, Arabian Sea (regional macrophyte community data) and the larger Indian Ocean (oceanic distribution data). Methods, The proposed index is derived from the Tulloss tripartite similarity index. The tripartite biogeographical index (TBI = ,F × C × G) is calculated for a specific taxon and incorporates several fundamental parameters of presence/absence data in grid cell (block) patterns. TBI accounts for the relative abundance of a taxon, the average grouping of its occurrences, the average of minimal absence intervals between taxon presences and the largest coherent cluster of taxon occurrences, and also incorporates dispersal aspects. The macrophytes from the case study are among the best documented marine organisms in the Indian Ocean. The regional distribution data from the Arabian Sea result from exhaustive species lists from Masirah Island (Oman) and the Socotra Archipelago (Yemen). Results, TBI values fit a linear scale corresponding to the proportional presence and the distributional spread of taxa within a given geographical area. The three functions that constitute TBI can be evaluated separately or in association with TBI, to give detailed information on the important factors that characterize the biogeographical distribution of a taxon (or larger entities consisting of multiple taxa such as communities). The case study on Arabian macrophytes clarifies the use and explanatory power of the index. Main conclusions, The biogeographical descriptors can be combined into an index which accurately quantifies taxon occurrences and distribution types on a single linear scale from rare/scattered to abundant/grouped. Together with its three functions, the index allows for a non-arbitrary selection of taxa and taxon groupings based on their distribution pattern. The analysis of TBI values for the Arabian macrophyte communities confirms previous biogeographical findings and enables more detailed statistical analyses of the distribution data. [source] A REVIEW OF EOCENE NUMMULITE ACCUMULATIONS: STRUCTURE, FORMATION AND RESERVOIR POTENTIALJOURNAL OF PETROLEUM GEOLOGY, Issue 1 2001A. Racey Eocene nummulite accumulations, also referred to as nummullte "banks", form Important hydrocarbon reservoirs in Tunisia and Libya and may constitute exploration targets in other parts of North Africa, the Mediterranean and the Middle East. Porosities commonly average 10,20% and permeabilities 10,50md. Foraminifera of the genus Nummulites may comprise up to 98% of the bioclasts in these carbonate reservoirs, although only one or two species may be present. The absence of associated fauna is generally taken to indicate an oligotrophic depositional environment. In this paper, the palaeoecology of the genus Nummulites is discussed together with depositional models for two nummulitic carbonate reservoirs , the Middle Eocene Seeb Limestone of Oman and the Early Eocene El Garia/Jdeir Formation of Tunisia and Libya. The El Garia and Seeb Limestone Formations were deposited in ramp settings, and comprise a series of amalgamated sheets or low-relief banks. In the Hasdrubal field offshore Tunisia, where the El Garia Formation constitutes the reservoir rock, most of the nummulites have been redeposited from shallow into deeper waters whilst in the Bourri field (offshore Libya) they occur as an in situ "bank". Nummulite accumulations often show evidence that both physical reworking (scouring, winnowing and imbrication) and biological processes (reproduction strategies and bioturbation) have influenced their formation. A general model is outlined for discriminating between physically and ecologically produced biofabrics, and the implications for reservoir quality are discussed. [source] TEMPERATURE THRESHOLD AS A BIOGEOGRAPHIC BARRIER IN NORTHERN INDIAN OCEAN MACROALGAE,JOURNAL OF PHYCOLOGY, Issue 4 2006Tom Schils The most eastern point of the Arabian Peninsula, Ras Al Hadd, marks the boundary between the Arabian Sea and the Gulf of Oman. This geographic landmark coincides with an abrupt floristic turnover, probably one of the sharpest biotic transitions known in marine biogeography. The floras of different Arabian localities across this floristic break were compared using macrophyte distribution data throughout the Indian Ocean and seasonal sea-surface temperature (SST) data. The localities from the Arabian Gulf and Gulf of Oman differ significantly from those of the Arabian Sea based on their species richness, species composition, average distribution range per species, general temperature affinity of the composing species, and seasonal temperature data of the coastal waters. Pooling the temperature data into two groups (SST3avg, average SST of the three warmest seasons; SSTmin, minimum of the seasonal SSTs) revealed a temperature limit at 28°C using both the temperature affinity data of the floras and the seasonal temperatures recorded for the specific Arabian localities, which significantly separates the Arabian Sea from localities of both Gulfs. Finally, SST data of the Indian Ocean were analyzed using this upper temperature threshold of macrophytes at 28°C and the lower temperature limit of corals at 25°C, revealing general macrophyte diversity patterns. [source] Dynamic social system in Nubian ibex: can a second mating season develop in response to arid climate?JOURNAL OF ZOOLOGY, Issue 3 2008A. Massolo Abstract We studied a population of Nubian ibex Capra ibex nubiana in the eastern extreme of its range, the hyper-arid central desert of the Sultanate of Oman. Long-term data were collected from January 1983 to December 1997 by direct observation, as well as VHF telemetry on 12 animals (eight from 1987 to 1990; four from 1994 to 1996). We recorded 884 sightings: 40.4% of single animals and 59.6% of groups. Although no significant monthly variation of group size (Jarman's Typical Group Size) was found, there were distinct peaks in March (4.0 ind. group,1) and September (5.1 ind. group,1). Groups of males and females formed especially in March and November, and female,kid groups in February and July,August. Our data may suggest two mating periods: the first one in autumn (similar to the rut of ibex in temperate mountain areas), with kids born in spring/early summer, after winter,spring rainfall, and the second one in spring, with kids born in late summer/autumn, before winter,spring rainfalls. We suggest that the second rutting period may have evolved as a micro-evolutionary process, with the local population adapting to hyper-arid environment constraints. The spring mating season may favour only females in prime conditions, who can afford a pregnancy in the local severe summers and will deliver kids when plant greening begins, in the autumn, whereas the autumn (original) mating season may be afforded by any female, but kids will be born in an unfavourable period, before the summer drought. [source] Complex behavioural pattern as an aid to identify the producer of Zoophycos from the Middle Permian of OmanLETHAIA, Issue 2 2009DIRK KNAUST The trace fossil Zoophycos is abundant in transgressive, shallow marine carbonates in the Middle Permian (Wordian) Khuff Formation of the Huqf-Haushi Uplift of Interior Oman. It often occurs as part of a complex (compound) trace fossil that comprises two integrated elements: (i) irregular galleries with straight to gently curved tunnels and interconnected shafts, and (ii) simple planar to complex spreiten structures with a marginal tube (Zoophycos). The galleries are characterized by irregularly winding, dichotomous branching, large variation in shape and size and circular to elliptical vertical cross-sections. Zoophycos consists of spreiten with a marginal tube, either originating as a simple lobe from the convex segment of a curved tunnel, or forming more complex, subcircular, spreiten systems parallel to bedding. The spreiten were formed by simple strip mining, where the animal defecated without producing faecal pellets. U-shaped marginal tubes indicate that the burrows were well aerated. The complex trace fossil points to combined dwelling and deposit-feeding behaviour, with irregular galleries in the firm substrate and Zoophycos spreiten in the softground below it. It can be assumed that the animal used the open tunnel system mainly for dwelling (domichnion) and possibly suspension feeding, but occasionally changed to deposit feeding while creating the spreiten (fodinichnion). The integration of the irregular galleries (tunnels and interconnected shafts) with the marginal tubes of Zoophycos suggests the same producer for this compound trace fossil. Many modern polychaetes produce very similar galleries within firm and soft substrates, and polychaetes are therefore interpreted as the most likely producers. Similarities between Permian and Triassic Zoophycos suggest comparable trace making behaviour before and after the end-Permian mass extinction. [source] Palaeoecological significance of a new Griesbachian (Early Triassic) gastropod assemblage from OmanLETHAIA, Issue 1 2005JAMES WHEELEY A new Early Triassic (Griesbachian) gastropod fauna from the Al Jil Formation of Oman is described. Early Triassic faunas from elsewhere (e.g. the Italian Dolomites and the western USA) are typically of low diversity and high dominance, usually attributed to environmental stress in the immediate aftermath of the end-Permian mass extinction event. The new Oman fauna has, by contrast, relatively high diversity, low dominance and a more even spread of individuals between taxa. It is the most diverse Griesbachian fauna known to date. This is attributed to the favourable (i.e. well-oxygenated) conditions under which the fauna lived. This uncharacteristic Griesbachian gastropod fauna demonstrates that, in the absence of oceanic anoxia, biotic recovery after the end-Permian extinction event may occur surprisingly quickly (within one conodont zone). The fauna is also partially silicified, which has increased its preservation potential relative to other Griesbachian gastropod assemblages. However, only one reappearing Lazarus genus is present in the Oman fauna. This suggests that there was some other control on the abundance of Lazarus genera at this time, other than the absence of silicified faunas as previously suggested. [source] Genetic structure of Euclea schimperi (Ebenaceae) populations in monsoonal fog oases of the southern Arabian PeninsulaNORDIC JOURNAL OF BOTANY, Issue 3-4 2007Jörg Meister Euclea schimperi, a widespread Afromontane shrub or tree, occurs in the Arabian Peninsula in fragmented, semi-evergreen or evergreen woodland refugia in wet escarpment localities of the western and southern mountain chains. In the southern coastal mountains, the (semi-) evergreen woodland with E. schimperi is close to its ecological limit and consequently today very rare, with the exception of the monsoonal fog oases of east Yemen and south Oman in the central south coast of the Arabian Peninsula. Due to the steep precipitation gradient from the centre to the western edge in this monsoon affected area, E. schimperi is found in two different habitat types: in continuous woodland belts in the Hawf and Dhofar mountains, and in isolated, scattered woodland patches in the Fartak Mountains. Ten populations (138 individuals) from across the southern Arabian distribution area of the species were analysed using chloroplast microsatellites and AFLP fingerprinting to a) reconstruct the phylogeographical pattern of E. schimperi on the southern Arabian Peninsula and b) to evaluate the consequences of population fragmentation on the genetic diversity harboured in isolated patches vs cohering stands. Phylogeographical reconstructions show that the distribution area of E. schimperi in the southern Arabian Peninsula is characterised by a geographical split that separates the southwestern populations (representated by material from Jabal Eraf and Jabal Uthmar), from the southcentral populations, which themselves are split from each other into a western (Ras Fartak) and an eastern refugium (Hawf/Dhofar). The analysis of the within-population genetic diversity in E. schimperi populations resulted in a slightly, but not significantly higher genetic variation in small and isolated woodland patches (HS=0.302) compared to larger, cohering stands (HS=0.291). [source] A new species of Kleinia (Asteraceae) from SomaliaNORDIC JOURNAL OF BOTANY, Issue 4 2004Mats Thulin The new species Kleinia caespitosa, from crevices in limestone rocks at 1850,1900 m in northern Somalia, is described and illustrated. It is compared to the widespread and sympatric K. grantii, as well as to K. saginata in Oman. [source] GUODUNITES, A LOW-PALAEOLATITUDE AND TRANS-PANTHALASSIC SMITHIAN (EARLY TRIASSIC) AMMONOID GENUSPALAEONTOLOGY, Issue 2 2009ARNAUD BRAYARD Abstract:, Based on new, bed-rock controlled material from Oman and Utah, USA, the Early Triassic genus Guodunites, which was recently erected on the basis of scarce specimens from northwestern Guangxi, South China, is now shown to be a representative of Proptychitidae. This solves the question of the previously unknown phylogenetic affinity of this genus. The genus is restricted to the late middle Smithian, and to date, its biogeographical distribution comprises Oman, South China and Utah, thus indicating an essentially low palaeolatitudinal distribution during the Early Triassic. Its palaeobiogeographical distribution further strengthens the existence of significant equatorial faunal exchanges between both sides of the Panthalassa at that time. It also suggests that, in addition to the potential stepping stones represented by Panthalassic terranes, vigorous equatorial oceanic currents must have contributed largely to the dispersal of ammonoids during such time intervals. [source] Cytokine profile of sickle cell disease in OmanAMERICAN JOURNAL OF HEMATOLOGY, Issue 4 2004Anil Pathare Abstract The aim of our study was to assess the cytokine profile of sickle cell disease (SCD) patients in steady state and in vaso-occlusive crisis (VOC). VOC has a complex nature, involving interactions between sickle red blood cells (RBC), the endothelium, and leucocytes. Endothelial damage due to recurrent adhesion of sickle RBCs may disrupt endothelial function, leading to altered cytokine release. It is therefore pertinent to study the cytokine profile of SCD patients in steady state and in crisis prior to exploring its contribution to vaso-occlusive manifestations, since it is believed that an altered balance of proinflammatory and anti-inflammatory cytokines plays an important role in painful crisis. Cytokines including IL-1,, IL-2, IL-4, IL-6, IL-8, TNF-,, and IFN-, were measured by commercially available ELISA kits in SCD patients (n = 60); in steady state (n = 26) and in painful crisis (n = 34) and compared with nonanemic age- and sex-matched normal Omani controls (n = 20). SCD patients in crisis showed elevated levels of TNF-, (P < 0.092) and IL-6 (P < 0.024) when compared with steady state. It was also observed that SCD patients in steady state showed a significant elevation in IL-1, (P < 0.04), IL-6 (P < 0.0001), and IFN-, (P < 0.02) as compared to normal subjects. It is thus evident that both type I and type II cytokines are significantly altered in SCD patients. In steady state, type II proinflammatory cytokines are elevated, whereas in crisis, an additional augmentation of type I cytokines occurs, with persistent elevation of type II cytokines, emphasizing the role of perturbed endothelium and activated monocytes in the pathophysiology of vaso-occlusion in sickle cell crisis. Am. J. Hematol. 77:323,328, 2004 © 2004 Wiley-Liss, Inc. [source] Discoveries of Neolithic prehistoric sites at Pleistocene carbonate rock shelters on the east coast of the UAEARABIAN ARCHAEOLOGY AND EPIGRAPHY, Issue 2 2006Cajus G. Diedrich Dr.Article first published online: 8 DEC 200 Three newly discovered prehistoric sites on the east coast of the United Emirates (UAE) are described. All are located on surfaces of Pleistocene carbonates or rock shelters that are generally rare along the eastern coast of the Gulf of Oman. Aqqah 1 (Le Meridien al Aqqah Beach Resort), the most important and best preserved of these sites, is a partially collapsed rock shelter with an exposed section, lithic finds and marine molluscs. Deriving an exact date from the material present is difficult because of a lack of comparanda. A bifacial fletched arrowhead made of yellow jasper and the lithic debris of five different raw materials as well as an undecorated ceramic fragment might suggest a date in the Late Neolithic or Early Bronze Age. The presence of many marine bivalves and snails with operculae, which differ from recent coastal species, indicates the collection and consumption of living molluscs by the prehistoric population of Aqqah. Nearby burials may be related to the rock shelters. [source] Trepanations from Oman: A case of diffusion?ARABIAN ARCHAEOLOGY AND EPIGRAPHY, Issue 2 2006Judith Littleton Trepanations have been described from various locations around the world leading to a suggestion that this is a cultural practice that has widely diffused from one or two centres (1). In the UAE the earliest trepanations date to the Neolithic, significantly earlier than trepanations in surrounding areas. The discovery of at least two crania in Oman, dating apparently to the early third millennium and resembling in technique and placement trepanations from north India may be evidence of the diffusion of a therapeutic practice from the Gulf to the subcontinent. However, the lack of any trepanation among the numerous contemporary skeletons from Bahrain suggests that any diffusion has distinct limits and that, as anthropological work from the South Pacific (2) indicates, practices like trepanation are often heavily embedded in broader, culturally located explanatory models. 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