Introduction: Framing difference: racial and ethnic studies in twentyfirst-century Britain

The events in Britain since the beginning of the new millennium starkly and dramatically reflect the continued salience of racial and ethnic difference. In media, political and academic discourse, the struggles over nationhood and multiculturalism, the duties of citizenship and the right to cultural expression, similarity and difference have been played out against global and national backdrops, and across many local stages. The articles in this volume aim to explore the contours of this changing terrain, and suggest new avenues for research and theorization. They are primarily an engagement with British debates and events, but seek to place these within a broader global and diasporic context. The aim of this introductory article is to sketch the background to the events that surround the production of these articles, to outline a broad conceptual overview of the current academic debates and to explore the links between each contribution.     

Africans in the diaspora: black-white earnings differences among America's Africans

The condition of Africans in the diaspora proffers insight into not just their adaptation to their new countries, but also the nature of racial stratification at their destinations. We examine race differences in earnings between black and white Africans in America and find sizeable differences among immigrants who have relatively similar human capital profiles. Whites have annual earnings 80 per cent higher than their black counterparts, and the gap in hourly wage is almost 48 per cent. More significantly, more than half (53 per cent) of the race difference in wages remains unexplained by earnings-related attributes such as education, occupation, and hours worked. We discuss these results against the backdrop of the ongoing debate on discrimination and the significance of race for socio-economic attainment in America.     

Religion,ethnicity and politics: Hindu and Muslim Indian immigrants in the United States

This article focuses on the political struggles between Hindu and Muslim Indian immigrant groups in the United States over the definition of "Indianness". Hindu Indian American organizations define India as a Hindu society and are strong supporters of the Hindu nationalist movement in India. Muslim Indian American organizations, on the other hand, view India as a multi-religious and multicultural society. They are striving to safeguard India's secularism and towards this end, have entered into coalitional relationships with lower caste groups. Both types of organizations are working to influence American and Indian politics in line with their respective interests, leading to an exacerbation of the conflict between the two immigrant groups. This article examines the reasons for this development and its implications, both for the development of an Indian American community in the United States and for religion and politics in India.     

The relation between the assimilation of methanol and glycerol in yeasts

Fifteen yeast strains of the genera Candida, Lodderomyces, Endomycopsis, Saccharomyces, Hansenula, Pichia and Torulopsis were investigated with respect to their ability to grow on methanol, glycerol and glucose as sole carbon and energy source. Eight of them can grow on both methanol and glycerol.Methanol is assimilated via triosephosphate (dihydroxyacetone) pathway. The dihydroxyacetone kinase is a key enzyme in methanol metabolism.The assimilation of glycerol can take place in bacteria via a phosphorylative or/and oxidative pathways. In general, the phosphorylative pathway is found in eucaryotes. In the present paper it is shown that in yeasts, which can utilize methanol and glycerol, too, glycerol is assimilated via an oxidative pathway, Dihydroxyacetone is a central intermediate in the assimilation of methanol as well as glycerol. It is metabolized by means of the dihydroxyacetone kinase.The enzyme formed during growth of Candida methylica on methanol does not differ from that of Candida valida H 122 after growing on glycerol as far as the regulatory properties are concerned.     

Sedimentary facies analysis of the subsurface triassic and hydrocarbon potential in the United Arab Emirates

Summary The Triassic sediments in the subsurface of the United Arab Emirates has been divided into three formations (from bottom to top): Sudair, Jilh (Gulailah) and Minjur. The Sudair Formation consists of four lithofacies units composed mainly of limestones and minor dolomites interbedded with terrigenous shaley mudstones and anhydritic dolomitic limestones. These were deposited in shallow marine supratidal to subtidal settings. The Jilh (Gulailah) Formation has five lithofacies units dominated by anhydritic dolomitic limestone, fine terrigenoclastic sediments and bioclastic and intraclastic limestones. The formation was laid down under lagoonal to supratidal sabkha conditions with little normal marine influence. The Minjur Formation is composed of three lithofacies units characterized by argillaceous quartzitic sandstones, shales, mudstones, dolomitic and ferruginous limestones with thin coal seams. These facies represent deposition in prograding delta lobes, reflecting humid continental to marginal-marine conditions. Diagenesis plays a major role in the reservoir development in the Triassic sediments, the pores are occluded by dolomite and anhydrite. The grains are compacted, leached or cemented by marine cements. Porosity generally ranges from fair to poor with values from 6% to 9% in the carbonates and from 6% to 15% in the clastics. Interparticle and vuggy porosities are the main pore types. The porosity was controlled by diagenesis, depth of burial and lithology. No oil has been discovered so far in the Triassic sediments of the United Arab Emirates but pronounced gas shows have been reported from offshore fields. Western offshore United Arab Emirates is a promising area for potential hydrocarbon accumulations. The Triassic sediments have low to moderate source rock potential; the organic matter is mainly sapropelic kerogen, and the degree of thermal alteration ranges between mature to highly mature stages.     

Gc subtypes in the middle east: Report on an Arab Moslem population from Israel

Gc subtypes were determined by isoelectrofocusing and immunofixation on 342 blood samples from an Arab Moslem population in Israel. Observed allele frequencies were: Gc^1F 0.2120, Gc^1S 0.6023, and Gc² 0.1857. Those are similar to formerly reported frequency data for other Middle Eastern populations. A discriminant analysis, performed on data from 35 populations, resulted in a satisfactory classification of population groups related through geographic and racial origin.     

Segmented assimilation and minority cultures of mobility

Recent work on second-generation immigrants posits that racial discrimination and a restructuring economy are likely to create different paths of assimilation for recent non-white immigrants than earlier European immigrants followed, and may even decouple acculturation and economic mobility. But while these discussions have considered the minority lower class as a possible destination for assimilation, middle-class minorities have been largely ignored. This article considers how the experiences of middle-class minorities might alter our models of second-generation incorporation. We propose that the minority middle classes share a minority culture of mobility, a set of cultural elements responsive to distinctive problems that usually accompany minority middle-class status, including problems of interracial encounters in public settings and inter-class relations within the minority community. We illustrate this minority culture of mobility with a brief case study of the African-American middle class, and discuss its implications for immigrants.     

Nitrate assimilation in coexisting vascular plants in mire and swamp forest habitats in Central Sweden

Summary In order to monitor the nitrate assimilation capability of mire plants, in vivo current and maximally induced nitrate reductase activity (NRA) were investigated in 14 species of vascular plants from four different sites in a central Swedish mire. One of the sites was a swamp forest. The plants studied included species with both wide and restricted ecological ranges, and the mire sites selected covered a wide range of plant productivity. At the most productive site, current NRA differed among coexisting species. This differentiation in the use of nitrate as a source of nitrogen suggested the possibility of resource partitioning with regard to nitrogen acquisition. Maximally induced NRA, measured 3 days after an addition of nitrate, was highest at the most productive sites and differed among coexisting species. Plant species characteristic of rich fens had the highest maximally induced NRA. In all species, there was a positive correlation between the ability to assimilate peaks of available nitrate and total leaf nitrogen concentration.     

Freshwater macrofauna of stagnant waters in Yemen Arab Republic

We inventorize the freshwater macrofauna of 4 different wadis, representing the low and highlands, in Yemen Arab Republic. The fauna comprised 6 molluscan, 21 Coleopteran, 8 Hemipteran, 2 amphibian and one fish species. Of the Coleoptera, 8 species are new records to yemen Arab Republic. The genus Exitianus is recorded for the first time in Yemen Arab Republic. Diversity in the uplands and lowlands was similar, but biomass was much higher in the lowlands than in the highlands.     

The impact of lead on the assimilation efficiency of laboratory-held Diplopoda (Arthropoda) preconditioned in different environmental situations

Summary In five diplopod species from three families collected from locations with different soil metal contents, the following parameters were examined: the litter mass (and energy) ingested per day, the mass (and energy) assimilation rates, and the litter mass (and energy) assimilated per day, when the diplopods were fed (1) uncontaminated and (2) artificially lead-enriched leaf litter. These parameters were compared between species and between animals from different sites. The mass and energy assimilation efficiencies depend on (1) the size of the species and (2) the collection site of the animals. Relative mass (and in three of the species examined also energy) assimilation was highest in those animals collected from the less contaminated sites. With artificial diets, specimens from a site with soil contaminated by heavy metals showed greater assimilation of both mass and energy than originally unaffected specimens. One species (Glomeris conspersa) was able to compensate for the low assimilation rate by increased consumption, and thus guarantee a sufficient energy supply. One of the other species (Polydesmus denticulatus), however, did not show this compensation. Animals of this species from less contaminated sites showed a very low absolute energy assimilation rate and high mortality under lead treatment.     

Cloning cultures: the social injustices of sameness

Cloning is widely considered only to be a biological discourse. Few, however, have paid attention to the cultural contexts that have made cloning conceivable. The relation between the biological and cultural considerations of cloning are revealed by the anxieties conjured up by the prospects of cloning human beings. By cloning we understand the reproduction of sameness which is deeply ingrained in the organization and reproduction of culture. The ease with which cloning has been taken up in contemporary thinking has been made possible by the widespread saturation of the normative assumption of socio-cultural sameness underpinning much of mainstream modern thinking around politics, law, education, management, aesthetics, the military and processes of production. We consider the cultural considerations regarding the reproduction of sameness and the implications of cloning for issues of social injustice.     

Cystic fibrosis in Lebanon: distribution of CFTR mutations among Arab communities

Cystic fibrosis (CF) is thought to be rare among the Arab populations from the Middle East and little data have been reported so far. We have studied a sample of 20 families living in Lebanon for several generations and who have at least one child with CF. These families are mainly from the Maronite, Greek Catholic, Greek Orthodox, Shiite or Sunnite groups. We found a 50% rate of consanguineous marriage, independent of the community of origin. The distribution of CF genotypes was determined through the screening of all exons of the CFTR (cystic fibrosis transmembrane conductance regulator) gene by the technique of denaturing gradient gel electrophoresis combined with asymmetric amplification DNA sequencing. A total of ten different mutations accounting for 87.5% of 32 unrelated CF alleles was identified, including two novel putative mutations (E672del and IVS21-28G→A). Three mutations, ΔF508 (37.5%), W1282X (15.6%), and N1303K (9.4%) accounted for 62.5% of CF alleles. Interestingly, in the Maronite group, 66.7% of the ΔF508 chromosomes were found to be associated with allele 7 of the IVS8(T)tract, contrasting with the absolute linkage disequilibrium between European ΔF508 chromosomes and allele 9. During this study, two previously undescribed polymorphisms (IVS14a + 17del5 and 2691T/C) were also identified. Received: 2 January 1997 / Accepted: 16 March 1997     

Sex differences in digestive traits in sexually size-dimorphic birds: Insights from an assimilation efficiency experiment on Black-tailed Godwit

Digestive assimilation efficiency is considered a trait with important implications for animal ecology. However, practically all studies have ignored the importance of sex differences in food assimilation efficiency (AE). Here, we investigated sex differences in dietary and physiological parameters in the Black-tailed Godwit Limosa limosa limosa feeding on rice seeds, a species with sexual dimorphism in body size and body mass. Gross daily food intake, gross energy intake, gross energy output and metabolizable energy intake did not vary significantly between sexes, but godwit females showed lower faeces energy density and higher AE than males. Mass-specific AE was similar in males and females, and the difference in AE could be attributed to the females' greater body mass. We suggest that a differential AE could play a role in explaining sex differences in habitat or micro-habitat selection during the non-breeding season in bird species with sexual dimorphism in size. Finally, we addressed the question about assimilation efficiency accuracy in models that estimate prey acquisitions by declining shorebirds as the Black-tailed Godwit.     

Observations on the diagenesis of the Lower Triassic Sudair Formation,Abu Dhabi,United Arab Emirates

Summary The Lower Triassic Sudair Formation in the United Arab Emirates (U.A.E.) ranges in thickness from 178–297 m and comprises three units consisting of interbedded limestone, argillaceous limestone, dolomite and anhydrite. The Lower Unit contains variable energy shallow marine, slightly argillaceous mudstones and subordinate ooliticpeloidal packstones and grainstones with minor dolomite and anhdrite. The Middle Unit consists of argillaceous and ferroan dolomite deposited in a lagoonal to supratidal setting. The Upper Unit comprises argillaceous mudstones and dolomites at the base grading upward into argillaceous anhydrite deposited in a restricted shallow marine to sabkha setting. These units represent the transition from a carbonate/evaporite shelf with significant terrestrial input to an evaporitic platform defined by an overall shallowing-upward sequence. Diagenesis in the Sudair includes extensive leaching of grain-supported carbonates, partial to complete dolomitization, evaportie formation, clay nucleation, fracturing/pressure solution, late cementation by coarse calcite spar and saddle dolomite, and hematite formation. These processes have had the cumulative effect of reducing the secondary porosity. Dolomitization occurred in two stages: an earlier progression of rhombic-sucrosic-aphanocrystalline dolomite, and a later coarse crystalline and saddle dolomite fracture fill.     

Microbial assimilation of alkyl nitro compounds and formation of nitrite

66 representative strains of bacteria, yeasts and fungi were tested for their ability to grow in a semidefined medium containing 0.5% nitroethane as a nitrogen source. About half of them were found capable of growing in the medium. Hansenula beijerinckii, Candida utilis, and Penicillium chrysogenum were most active in assimilating nitroethane. 2-Nitropropane inhibited growth of most of the microorganisms tested in a medium containing 0.2% peptone and 0.2% glycerol. Hansenula mrakii was found to grow rapidly in the nitroethane-peptone medium after a lag phase. Nitrite was accumulated in the culture fluid after the phase of logarithmic multiplication, and increased with increase of the growth, followed by a decline after the maximum growth. The alkyl nitro compounds were oxidatively denitrified to form nitrite by the crude enzyme from Hansenula mrakii. Nitroethane was generally a poor substrate, but was the best inducer to produce the nitro compounds oxidizing enzyme. 2-Nitropropane and nitroethane were enzymatically oxidized to and acetone and acetaldehyde, respectively, which were isolated as 2,4-dinitrophenylhydrazones and identified. Nitrite formed was found to be reduced into ammonia by the intact cells and also the crude enzyme.     

Bacterial assimilation of d- and l-2-chloropropionates and occurrence of a new dehalogenase

The occurrence of a new bacterial dehalogenase acting on both the optical isomers of 2-halogenated alkanoic acids was demonstrated. When the haloalkanoic acid-utilizing bacteria were screened in a medium containing dl-2-chloropropionate as a sole carbon source, two types of bacteria were isolated: (1) a few strains utilizing both d- and l-isomers of 2-chloropropionate and (2) strains utilizing only the l-isomer. A dehalogenating enzyme was obtained from the cells of Pseudomonas sp. which is able to utilize both isomers. The crude enzyme catalyzed the dehalogenation of d- and l-2-chloropropionates to yield l- and d-isomers of lactate, respectively. The enzyme showed the same pH optimum and heat inactivation rate for the d- and l-isomers. Apparent K _m values for d- and l-2-chloropropionates were 4.5 and 1.0 mM, respectively. The enzyme acted specifically on 2-haloalkanoic acids. Activity staining of disc-gels electrophoresed witg the crude enzyme preparation showed that the dehalogenation of d- and l-2-chloropropionates, monochloroacetate, dichloroacetate, 2,2-dichloropropionate, and dl-2-chlorobutyrate is due to a single protein.Abbreviations MCA monochloroacetic acid - DCA dichloroacetic acid - TCA trichloroacetic acid - 2 MCPA 2-monochloropropionic acid - 22 DCPA 2,2-dichloropropionic acid - 3 MCPA 3-monochloropropionic acid - 2 MCBA 2-monochlorobutyric acid - 3 MCBA 3-monochlorobutyric acid - 4 MCBA 4-monochlorobutyric acid     

小麦品种间感染纹枯病的差异及普遍率与严重度的关系

通过人工接菌方法比较了６个小麦主栽品种间感染纹枯病的差异,结果表明,高感类型有阜阳８６１、温麦４号和皖麦１９,中感类型有扬麦１５８、豫麦１８和豫麦２１．各品种苗期病株率反映不出品种感病程度的差异,以灌浆后期的病情指数为标准比较品种间抗感染程度较为适宜．认为寄主生育阶段影响小麦纹枯病的ＩＳ关系．回归分析表明,按内茎和外茎发病程度分级可减少田间调查误差,且省时省工．     

Upper Triassic (Norian) hypercalcified sponges from the Musandam Peninsula (United Arab Emirates and Oman)

Supercalcified sponges, including sphinctozoans, inozoans, chaetetids, spongiomorphids, occurring in Upper Triassic (Norian-Rhaetian) shallow-marine limestones of Musandam Mountains in United Arab Emirates (UAE), are described. The following taxa were determined: sphinctozoans: Hajarispongia osmani Senowbari-Daryan and Yancey, Nevadathalamia arabica n. sp., Nevadathalamia conica n. sp., Fanthalamia milahaensis n. sp., Iranothalamia incrustans (Boiko), Cinnabaria regularis n. sp.; inozoans: Cavsonella triassica n. sp., Molengraaffia regularis Vinassa de Regny, Peronidella? sp., Circopora cf. caucasica Moiseev, Circopora? sp.; spongiomorphids: Spongiomorpha sp.; chaetetids: Lovcenipora chaetetiformis Vinassa de Regny, Lovcenipora musandamensis n. sp., Lovcenipora sp., chaetetid sponge gen. et sp. indet. The most abundant sponge in the studied material is Nevadathalamia arabica n. sp. The described sponge association of the Arabian shelf (Musandam Mountains) shows close affinity to the sponge association known from age-equivalent terranes in the Panthalassa Ocean (Sonora Mountains in Mexico; Pilot Mountains in Nevada, USA), but is remarkably different from sponge associations in carbonates bordering the Tethys. This difference goes along with the biogeography of wallowaconchid bivalves and is most likely attributed to climatic, palaeogeographic or oceanographic factors.