The factors controlling the distribution of carbonate content in Kuwait Bay sediments

The present study has been undertaken to determine the nature and the factors controlling the distribution of carbonate content in Kuwait Bay sediments. The carbonate content that may be deposited with Kuwait Bay sediments is attributed to the interplay of the deposits fallout from the dust storms over Kuwaiti territory, the deposits carried in suspension by the currents from Shatt Al-Arab area and to the skeletal parts of microorganisms that may be originated in the sediments. The carbonate content increases in the coarse sediments rather than in the fine sediments. The mineral components of the carbonate present are in the form of calcite, aragonite and some dolomite. Therefore, the texture of the sediments, the rate of deposition in addition to the biological interference may exert a considerable control over carbonate distribution.     

The physics of precipitation in cumulus clouds

Summary Over the past several years, the University of Chicago has conducted a program of research into the physics and chemistry of cumulus cloud precipitation. From these measurements it has been possible to isolate the sublimation-coalescence mechanism (Bergeron process) from the condensation-coalescence mechanism and to estimate the relative role of each process in the formation of rain n cumulus clouds. It is found that size of cloud capable of raining is a strong function of geography, that the environment of the cloud is very important in determining the probability of rain and that liquid water content is one of the most important within-cloud parameters.An essential part of the research concerned cloud treatment. Definite, positive treatment effects were demonstrated for rain initiation through coalescence using water spray. No effects were detectable from dry ice seeding of subcooled clouds, although any such effects may have been obscured by sample size (27 cloud pairs).Text of paper presented before Physical Society and Royal Meteorological Society Joint Conference on Cloud Physics, London, England, Jan. 4–5, 1956. The research reported in this paper has been sponsored by the Geophysics Research. Directorate of the Air Force Cambridge Research Center, Air Research and Development Command under Contract Nos. AF 19 (604)-618 and AF 19 (604)-1388.     

Mean Profiles of Moisture Fluxes in Snow-Filled Boundary Layers

Profiles of moisture fluxes have been examined for convective boundary layers containing clouds and snow, using data derived from aircraft measurements taken on four dates during the 1983/1984 University of Chicago lake-effect snow project. Flux profiles were derived from vertical stacks of aircraft cross-wind flight legs taken at various heights over Lake Michigan near the downwind shore. It was found that, if ice processes are taken into account, profiles of potential temperature and water content were very similar to those presented in past studies of convective boundary layers strongly heated from below. Profiles of total water content and equivalent potential temperature adjusted for ice were nearly invariant with height, except very near the top of the boundary layer, suggesting that internal boundary-layer mixing processes were rapid relative to the rates at which heat and vapour were transported into the boundary layer through entrainment and surface fluxes. Ice was found to play a significant, measurable role in boundary-layer moisture fluxes. It was estimated that 40 to 57% of the upward vapour flux was returned to the surface in the form of snow, converting about 45 to 64% of the surface latent heat flux into sensible heat in the snow-producing process. Assuming advective fluxes are relatively small (thought to be appropriate after the first few tens of km over the lake as suggested by past studies), the boundary layer was found to warm at a rate faster than could be explained by surface heat fluxes and latent heat releases alone, the remainder of the heating presumably coming from radiational processes and entrainment. Discussions of moisture phase change processes throughout the boundary layer and estimates of errors of these flux measurements are presented.     

A crustal suture and lineament in North Africa

A possible suture between an old craton in West Africa and the Arabian—Nubian shield is marked by a persistent zone of Phanerozoic weakness. This zone extends between the Nile and Niger deltas and passes through the Qattara embayment, along the Bahariya fault, through the Kufra basin, between the Tibesti and Jabal al Uwaynat massifs, through the Bahr el Ghazal and Lake Chad areas, and along the Benoue trough.     

First international payment for marine ecosystem services: The case of the Banc d’Arguin National Park,Mauritania

This article investigates whether the European Union-Mauritania fisheries agreement, which allocates part of the Europe's financial contribution to the conservation of marine ecosystems located within the Banc d’Arguin National Park, can be regarded as a payment for ecosystem service. A framework for qualification as such payment scheme was established based on an extensive literature review. The criteria identified for the qualification as a payment to ecosystem service pertain to: (1) the definition of the ecosystem service(s) involved; (2) the mechanism involved by the payment; and (3) the nature of the transaction. Interviews with local beneficiaries and subsequent data analysis led to the conclusion that this mechanism could be regarded as a payment to ecosystem service and so, through the European Union-Mauritania Fisheries agreement, the European Union were investing to protect local fish resources that could be exploited by its fishing fleet. This agreement, involving the first International Payment to Ecosystem Service of this kind, marks an important step towards better consideration of marine conservation in international public policy and foreign fishing policy in particular. However, this payment is small when compared to revenues generated through the exploitation of developing countries’ fishing grounds by fishing countries. Nevertheless it opens the door for more detailed applications of payment to ecosystem service schemes to other ecosystems contexts, and can provide a useful alternative source of financing of marine biodiversity conservation.     

GIS and multi-criteria analysis to select potential sites of agro-industrial complex

The selection of the potential sites to the creation of an agro-industrial complex requires a large amount of spatial information. Geographical information systems are capable of managing this information, providing the ability to integrate multiple layers of information and deriving new ones. This study incorporates environmental, social, economic, geological and infrastructural data. A multi-criteria analysis is performed to select the potential sites to the creation of an agro-industrial complex in the city of Sfax (the southern coast of Tunisia). The comparison by pair method adopted in this paper, based on a linear combination pondered after having assigned to every factor of decision a coefficient of level-headedness, creates many scenarios among which we selected the sustainable development one. This scenario assigned the highest weight to the economical, environmental and social factors (0.3 for each factor), which shows the presence of nine suitable sectors for the creation of an agro-industrial complex. The ELECTRE method enabled us to make a site ordering for the identification of the most three appropriate sites.     

Lithospheric extension and the opening of the Red Sea: sediment-basalt relationships in Yemen*

This paper analyses new field and radiometric age data on the timing of extension, sedimentation and magmatism related to the opening of the Red Sea. The first evidence of widespread extension is found in synsedimentary fissures in the fluviatile to shallow marine Tawilah Formation of Cretaceous to early Tertiary age. The first indication of magmatism is the eruption of alkaline basalts (43.5–21.2 Ma) on to marine and non-marine sandstones of lower to middle Tertiary age. The lack of an angular unconformity at the sediment-basalt contact, over a period of 25 Myr, corroborates a diachronous relationship between the Tawilah sandstones and the Yemen Volcanics. These data also indicate that the onset of volcanism in Yemen was in the Eocene, as is the case in Ethiopia and Saudi Arabia. A passive rifting model is supported by early extension and sedimentation followed by syn- and post-tectonic magmatism.     

On the iron interpretation of the 6.4 keV emission line from SGR 1900+14

A 6.4 keV emission line was discovered in an unusual burst from the soft gamma repeater SGR 1900+14 with the Rossi X-ray Timing Explorer (RXTE). The line was detected in part of a complex multipeak precursor that preceded the unusual burst of 1998 August 29, i.e. two days after the giant flare of August 27 from the source. The origin of the line was not firmly identified and two possible interpretations were equally plausible including (a) Kα fluorescence from a small iron rich material that was ejected to the magnetosphere during the August 27 flare, and (b) proton or α-particle cyclotron resonance. If the iron scenario was correct, we expect to find evidence for the line during the intervening interval between the flare and the August 29 burst, i.e. on August 28. Here we present the results of the August 28 burst observation, taken with RXTE. We detect a total of seven bursts whose individual and joint spectra do not show evidence for spectral lines. We also investigated a sample of nine bursts before and after the August 29 burst (from 1998 June to December) that do not reveal evidence for a spectral line near 6.4 keV or elsewhere. These results disfavor the iron scenario and make the proton/α-particle cyclotron resonance interpretation more plausible. The appearance of the emission line in part of a complex burst and its absence from the studied sample indicate that the line is likely due to a transient phenomenon that may depend on the burst morphology, energetics and the properties of the emission region.      

Does salinity change determine zooplankton variability in the saline Qarun Lake(Egypt)?

Zooplankton and 14 abiotic variables were studied during August 2011 at 10 stations in Lake Qarun,Egypt.Stations with the lowest salinity and highest nutrient concentrations and turbidity were close to the discharge of waters from the El-Bats and El-Wadi drainage systems.A total of 15 holozooplankton species were identified.The salinity in Lake Qarun increased and fluctuated since 1901:12 g/L in 1901;8.5 g/L in 1905;12.0 g/L in 1922;30.0 g/L in 1985;38.7 g/L in 1994;35.3 g/L in 2006,and 33.4 g/L in 2011.The mean concentration of nutrients(nitrate,nitrite and orthophosphate) gradually increased from 35,0.16 and 0.38 ? g/L,respectively,in 1953–1955 to 113,16.4,and 30.26 ? g/L in 2011.From 1999–2003 some decrease of species diversity occurred.Average total zooplankton density was 30 000 ind./m 3 in 1974–1977;356 125 ind./m 3 in 1989;534 000 ind./m 3 in 1994–1995;from 965 000 to 1 452 000 ind./m 3 in 2006,and 595 000 ind./m 3 in 2011.A range of long-term summer salinity variability during the last decades was very similar to a range of salinity spatial variability in summer 2011.There is no significant correlation between zooplankton abundance and salinity in spatial and long-term changes.We conclude that salinity fluctuations since at least 1955 did not directly drive the changes of composition and abundance of zooplankton in the lake.A marine community had formed in the lake,and it continues to change.One of the main drivers of this change is a regular introduction and a pressure of alien species on the existent community.Eutrophication also plays an important role.The introduction of Mnemiopsis leidyi,first reported in 2014,may lead to a start of a new stage of the biotic changes in Lake Qarun,when eutrophication and the population dynamics of this ctenophore will be main drivers of the ecosystem change.     

The meteoritic origin of Tutankhamun's iron dagger blade

Scholars have long discussed the introduction and spread of iron metallurgy in different civilizations. The sporadic use of iron has been reported in the Eastern Mediterranean area from the late Neolithic period to the Bronze Age. Despite the rare existence of smelted iron, it is generally assumed that early iron objects were produced from meteoritic iron. Nevertheless, the methods of working the metal, its use, and diffusion are contentious issues compromised by lack of detailed analysis. Since its discovery in 1925, the meteoritic origin of the iron dagger blade from the sarcophagus of the ancient Egyptian King Tutankhamun (14th C. BCE) has been the subject of debate and previous analyses yielded controversial results. We show that the composition of the blade (Fe plus 10.8 wt% Ni and 0.58 wt% Co), accurately determined through portable x‐ray fluorescence spectrometry, strongly supports its meteoritic origin. In agreement with recent results of metallographic analysis of ancient iron artifacts from Gerzeh, our study confirms that ancient Egyptians attributed great value to meteoritic iron for the production of precious objects. Moreover, the high manufacturing quality of Tutankhamun's dagger blade, in comparison with other simple‐shaped meteoritic iron artifacts, suggests a significant mastery of ironworking in Tutankhamun's time.